Laminate, method for manufacturing laminate, and color-changeable adhesive sheet

Abstract

To provide a laminate which is suitable for suppressing a discolored part discolored due to external stimulation from deteriorating due to external light, a production method of the laminate, and a color variable adhesive sheet for producing the laminate.SOLUTION: A laminate 1 comprises: an adherend 2; an adhesive agent layer 3; and an oxygen barrier layer 4 in the order in a thickness direction. The adhesive agent layer 3 has a discolored part 10 discolored due to external stimulation. An oxygen transmission rate of the oxygen barrier layer 4 is equal to or less than 200 cm3 / m2 day atm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate, a method for manufacturing the laminate, and a color-changeable adhesive sheet. More specifically, the present invention relates to a laminate, a method for manufacturing the laminate, and a color-changeable adhesive sheet for manufacturing the laminate. [Background technology]

[0002] Display panels such as organic EL panels have a laminated structure including a pixel panel, a cover member, etc. In the manufacturing process of such display panels, for example, a transparent adhesive sheet is used to bond the elements included in the laminated structure together.

[0003] It has also been proposed to use an adhesive sheet having colored portions pre-formed in predetermined locations on the sheet to provide design, shielding properties, anti-reflection properties, etc. as a transparent adhesive sheet to be placed on the light-emitting side (image display side) of a pixel panel in a display panel. Such an adhesive sheet is described, for example, in Patent Document 1 listed below. Patent Document 1 specifically describes an adhesive sheet having colored portions containing a carbon black pigment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-203810 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, there are cases where pressure-sensitive adhesive sheets are required to be transparent from the viewpoint of inspection and the like.

[0006] In such cases, the use of an adhesive sheet that can change color in response to an external stimulus is considered. Specifically, such an adhesive sheet changes color (becomes colored) when an external stimulus is applied.

[0007] In other words, with this adhesive sheet, the adhesive layer can be colored by irradiating it with active light rays at any time, thereby forming discolored areas in the adhesive layer that provide design, shielding, and anti-reflection properties.

[0008] On the other hand, in such a pressure-sensitive adhesive sheet, the discolored portion that has been discolored by an external stimulus may be deteriorated by external light.

[0009] The present invention provides a laminate suitable for preventing deterioration of discolored portions caused by external stimuli due to external light, a method for manufacturing the laminate, and a color-changeable adhesive sheet for manufacturing the laminate. [Means for solving the problem]

[0010] The present invention [1] is a pressure-sensitive adhesive sheet comprising an adherend, a pressure-sensitive adhesive layer, and an oxygen barrier layer in this order in the thickness direction, the pressure-sensitive adhesive layer having a discolored portion that has been discolored by an external stimulus, and the oxygen barrier layer having an oxygen permeability of 200 cm 3 / m 2 ·day·atm or less, laminated body.

[0011] The present invention [2] includes the laminate according to the above [1], wherein the adhesive layer contains an adhesive composition and a photoacid generator, and the adhesive composition contains a leuco dye.

[0012] The present invention [3] includes the laminate described in [1] or [2] above, which has an active energy ray-blocking layer on one thickness-wise surface of the oxygen barrier layer and / or on the other thickness-wise surface of the oxygen barrier layer.

[0013] The present invention [4] comprises a first step of arranging a pressure-sensitive adhesive layer on one surface in the thickness direction of an adherend, a second step of forming a discolored portion in the pressure-sensitive adhesive layer by an external stimulus, and a third step of arranging an oxygen barrier layer on one surface in the thickness direction of the pressure-sensitive adhesive layer, wherein the oxygen permeability of the oxygen barrier layer is 200 cm 3 / m2 The method for producing a laminate according to any one of the above [1] to [3] includes a method for producing a laminate according to any one of the above [1] to [3], wherein the temperature is 100°C / day·atm or less.

[0014] The present invention [5] is a pressure-sensitive adhesive layer and an oxygen barrier layer, which are sequentially provided in the thickness direction, and the pressure-sensitive adhesive layer can be discolored by an external stimulus, and the oxygen barrier layer has an oxygen permeability of 200 cm 3 / m 2 It is a variable color adhesive sheet that is less than 1000 times the humidity of the air per minute.

[0015] The present invention [6] includes the color-changeable pressure-sensitive adhesive sheet according to the above [5], wherein the oxygen barrier layer is disposed directly on one surface in the thickness direction of the pressure-sensitive adhesive layer.

[0016] The present invention [7] further includes the color-changeable adhesive sheet according to the above [5] or [6], which further comprises an active energy ray-blocking layer. [Effects of the Invention]

[0017] The laminate of the present invention has an oxygen permeability of 200 cm 3 / m 2 It has an oxygen barrier layer that is less than 1000 kJ / day atm. This prevents deterioration of discolored areas due to external light.

[0018] The method for producing the laminate of the present invention is to form a laminate having an oxygen permeability of 200 cm on one side of the pressure-sensitive adhesive layer in the thickness direction. 3 / m 2 The third step is to provide an oxygen barrier layer with an oxygen barrier strength of 1000 ppm or less per day. This makes it possible to manufacture a laminate that can suppress deterioration of discolored areas due to external light.

[0019] The color-changeable adhesive sheet of the present invention has an oxygen permeability of 200 cm 3 / m 2 This allows the manufacture of a laminate that can suppress deterioration of discolored areas due to external light. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic cross-sectional view of one embodiment of the laminate of the present invention. [Figure 2] Fig. 2 is a schematic diagram showing one embodiment (Method 1A) of the method for producing a laminate of the present invention. Fig. 2A shows the first step of preparing an adherend. Fig. 2B shows the first step of arranging a pressure-sensitive adhesive layer on one surface of the adherend in the thickness direction. Fig. 2C shows the second step of forming a discolored portion in the pressure-sensitive adhesive layer by an external stimulus. Fig. 2D shows the third step of arranging an oxygen barrier layer on one surface of the pressure-sensitive adhesive layer in the thickness direction. [Figure 3] Fig. 3 is a schematic diagram showing one embodiment (Method 1B) of the method for producing a laminate of the present invention. Fig. 3A shows the third step of preparing a pressure-sensitive adhesive layer. Fig. 3B shows the third step of arranging an oxygen barrier layer on one thickness-wise surface of the pressure-sensitive adhesive layer. Fig. 3C shows the first step of arranging a pressure-sensitive adhesive layer on one thickness-wise surface of an adherend. Fig. 3D shows the second step of forming a discolored portion in the pressure-sensitive adhesive layer by an external stimulus. [Figure 4] Fig. 4 is a schematic diagram showing one embodiment (Method 1C) of the method for producing a laminate of the present invention. Fig. 4A shows the first step of preparing an adherend. Fig. 4B shows the first step of arranging a pressure-sensitive adhesive layer on one thickness-wise surface of the adherend. Fig. 4C shows the third step of arranging an oxygen barrier layer on one thickness-wise surface of the pressure-sensitive adhesive layer. Fig. 4D shows the second step of forming a discolored portion in the pressure-sensitive adhesive layer by an external stimulus. [Figure 5] Fig. 5 is a schematic diagram showing one embodiment (Method 2A) of the method for producing a laminate of the present invention. Fig. 5A shows the second step of preparing a pressure-sensitive adhesive layer. Fig. 5B shows the second step of forming a discolored portion in the pressure-sensitive adhesive layer by an external stimulus. Fig. 5C shows the first step of arranging a pressure-sensitive adhesive layer on one surface in the thickness direction of an adherend. Fig. 5D shows the third step of arranging an oxygen barrier layer on one surface in the thickness direction of the pressure-sensitive adhesive layer. [Figure 6]Fig. 6 is a schematic diagram showing one embodiment (method 2B) of the method for producing a laminate of the present invention. Fig. 6A shows the second step of preparing a pressure-sensitive adhesive layer. Fig. 6B shows the second step of forming a discolored portion in the pressure-sensitive adhesive layer by an external stimulus. Fig. 6C shows the third step of arranging an oxygen barrier layer on one thickness-wise surface of the pressure-sensitive adhesive layer. Fig. 6D shows the first step of arranging a pressure-sensitive adhesive layer on one thickness-wise surface of an adherend. [Figure 7] Fig. 7 is a schematic diagram showing one embodiment (method 2C) of the method for producing a laminate of the present invention. Fig. 7A shows the third step of preparing a pressure-sensitive adhesive layer. Fig. 7B shows the third step of arranging an oxygen barrier layer on one thickness-wise surface of the pressure-sensitive adhesive layer. Fig. 7C shows the second step of forming a discolored portion in the pressure-sensitive adhesive layer by an external stimulus. Fig. 7D shows the first step of arranging a pressure-sensitive adhesive layer on one thickness-wise surface of an adherend. [Figure 8] Fig. 8 shows a cross-sectional view of one embodiment of a laminate including an active energy ray-blocking layer. Fig. 8A shows a cross-sectional view of a laminate including an active energy ray-blocking layer on one thickness-wise surface of an oxygen barrier layer. Fig. 8B shows a cross-sectional view of a laminate including an active energy ray-blocking layer on the other thickness-wise surface of an oxygen barrier layer. Fig. 8C shows a cross-sectional view of a laminate including active energy ray-blocking layers on one thickness-wise surface of a barrier layer and the other thickness-wise surface of an oxygen barrier layer. [Figure 9] Fig. 9 shows a cross-sectional view of an embodiment of a laminate comprising at least one selected from the group consisting of an active energy ray-blocking layer, a substrate, and an intermediate layer. Fig. 9A shows a cross-sectional view of a laminate comprising an adherend, a pressure-sensitive adhesive layer, an intermediate layer, an active energy ray-blocking layer, and an oxygen barrier layer, arranged in this order toward one side in the thickness direction. Fig. 9B shows a cross-sectional view of a laminate comprising an adherend, a pressure-sensitive adhesive layer, a substrate, an active energy ray-blocking layer, and an oxygen barrier layer, arranged in this order toward one side in the thickness direction. Fig. 9C shows a cross-sectional view of a laminate comprising an adherend, a pressure-sensitive adhesive layer, an oxygen barrier layer, an active energy ray-blocking layer, and a substrate, arranged in this order toward one side in the thickness direction. [Figure 10] FIG. 10 is a schematic cross-sectional view of one embodiment of a laminate including a surface protective layer. [Figure 11]FIG. 11 shows a cross-sectional view of one embodiment of the color-changeable adhesive sheet of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the laminate of the present invention will be described with reference to FIG.

[0022] In FIG. 1, the up-down direction of the paper is the up-down direction (thickness direction). The upper side of the paper is the top side (one side in the thickness direction). The lower side of the paper is the bottom side (the other side in the thickness direction). The left-right direction and the depth direction of the paper are surface directions that are perpendicular to the up-down direction. Specifically, they follow the directional arrows in each figure.

[0023] 1.Laminate The laminate 1 has a film shape (including a sheet shape) with a predetermined thickness. The laminate 1 extends in a plane direction perpendicular to the thickness direction. The laminate 1 has a flat upper surface and a flat lower surface.

[0024] 1, the laminate 1 includes, in this order toward one side in the thickness direction, an adherend 2, a pressure-sensitive adhesive layer 3, and an oxygen barrier layer 4. More specifically, the laminate 1 includes an adherend 2, a pressure-sensitive adhesive layer 3 disposed directly on the upper surface (one surface in the thickness direction) of the adherend 2, and an oxygen barrier layer 4 disposed directly on the upper surface (one surface in the thickness direction) of the pressure-sensitive adhesive layer 3.

[0025] The thickness of the laminate 1 is, for example, 1000 μm or less, or preferably 200 μm or less, and for example, 10 μm or more, or preferably 25 μm or more.

[0026] 2.Adherent Examples of the adherend 2 include optical devices, electronic devices, and components thereof.

[0027] 1, the adherend 2 has a flat plate shape, but there are no particular limitations on the shape of the adherend 2. Various shapes can be selected for the shape of the adherend 2 depending on the type of optical device, electronic device, and structural parts thereof.

[0028] Furthermore, in the second step of the method for producing the laminate 1 described below, when active energy rays are irradiated from the adherend 2 side, an adherend that transmits active energy rays is selected as the adherend 2.

[0029] Examples of adherends that transmit active energy rays include adherends that transmit ultraviolet rays.

[0030] Examples of adherends that transmit ultraviolet light include alkali-free glass and PET film.

[0031] The adherend that transmits ultraviolet light has a total light transmittance (JIS K 7375-2008) of, for example, 80% or more, or preferably 85% or more.

[0032] 3. Adhesive layer The pressure-sensitive adhesive layer 3 is formed from a pressure-sensitive adhesive composition, that is, the pressure-sensitive adhesive layer 3 contains a pressure-sensitive adhesive composition.

[0033] The pressure-sensitive adhesive layer 3 is a transparent (visible light transmissive) pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer 3 has a total light transmittance (JIS K 7375-2008) of, for example, 80% or more, or preferably 85% or more.

[0034] The adhesive composition includes a base polymer, a compound that develops color upon reaction with an acid, and an acid generator.

[0035] The base polymer is an adhesive component that imparts adhesiveness to the adhesive layer 3. The base polymer exhibits rubber elasticity in the room temperature range. Examples of the base polymer include acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluoropolymers. From the viewpoint of ensuring good transparency and adhesiveness in the adhesive layer 3, an acrylic polymer is preferably used as the base polymer.

[0036] The content of the base polymer in the adhesive layer 3 is, for example, 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more, from the viewpoint of properly exhibiting the functions of the base polymer in the adhesive layer 3.

[0037] An acrylic polymer is a polymer obtained by polymerizing a monomer component containing, for example, 50% by mass or more of a (meth)acrylic acid alkyl ester. "(Meth)acrylic acid" means acrylic acid and / or methacrylic acid.

[0038] Examples of (meth)acrylic acid alkyl esters include (meth)acrylic acid alkyl esters having a linear or branched alkyl group having 1 to 20 carbon atoms. Examples of such (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isopropyl (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, and isopropyl (meth)acrylate. Examples of the alkyl (meth)acrylate include 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, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. The alkyl (meth)acrylate esters may be used alone or in combination of two or more. The alkyl (meth)acrylate esters are preferably alkyl acrylates having an alkyl group having 1 to 12 carbon atoms, and more preferably methyl methacrylate, n-butyl acrylate, or 2-ethylhexyl acrylate.

[0039] The proportion of the (meth)acrylic acid alkyl ester in the monomer components is, for example, 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more, from the viewpoint of appropriately exhibiting basic properties such as adhesiveness in the adhesive layer 3. The proportion is, for example, 99% by mass or less.

[0040] The monomer component may include a copolymerizable monomer that is copolymerizable with the (meth)acrylic acid alkyl ester. Examples of the copolymerizable monomer include a monomer having a polar group (polar group-containing monomer). The polar group-containing monomer is useful for modifying the acrylic polymer, such as by introducing crosslinking points into the acrylic polymer and ensuring the cohesive strength of the acrylic polymer.

[0041] Examples of polar group-containing monomers include hydroxyl group-containing monomers, monomers having a nitrogen atom-containing ring, and carboxyl group-containing monomers. The copolymerizable monomer preferably includes at least one selected from the group consisting of hydroxyl group-containing monomers, monomers having a nitrogen atom-containing ring, and carboxyl group-containing monomers. More preferably, the copolymerizable monomer includes a carboxyl group-containing monomer.

[0042] Examples of hydroxyl group-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, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, and preferably 2-hydroxyethyl acrylate.

[0043] The proportion of the hydroxyl group-containing monomer in the monomer components is, for example, 1% by mass or more, preferably 3% by mass or more, and more preferably 5% by mass or more, from the viewpoints of introducing a crosslinked structure into the acrylic polymer and ensuring cohesive strength in the pressure-sensitive adhesive layer 3. From the viewpoints of adjusting the viscosity of the polymerization reaction solution during acrylic polymer polymerization and adjusting the polarity of the acrylic polymer (which is related to the compatibility between the acrylic polymer and various additive components in the pressure-sensitive adhesive layer 3), the proportion is, for example, 30% by mass or less, and preferably 20% by mass or less.

[0044] Examples of monomers having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, 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-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, and N-vinylisothiazole, and preferably N-vinyl-2-pyrrolidone.

[0045] The proportion of the nitrogen atom-containing ring monomer in the monomer components is, for example, 1% by mass or more, preferably 3% by mass or more, and more preferably 5% by mass or more, from the viewpoints of ensuring the cohesive strength of the pressure-sensitive adhesive layer 3 and the adhesive strength to the adherend in the pressure-sensitive adhesive layer 3. From the viewpoints of adjusting the glass transition temperature of the acrylic polymer and adjusting the polarity of the acrylic polymer (which is related to the compatibility of the acrylic polymer with various additive components in the pressure-sensitive adhesive layer 3), the proportion is, for example, 30% by mass or less, preferably 20% by mass or less.

[0046] Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. Preferred examples of the carboxyl group-containing monomer include acrylic acid.

[0047] The proportion of the carboxyl group-containing monomer in the monomer components is, for example, 1% by mass or more, preferably 3% by mass or more, from the viewpoints of introducing a crosslinked structure into the acrylic polymer, ensuring cohesive strength in the pressure-sensitive adhesive layer 3, and ensuring adhesive strength to the adherend in the pressure-sensitive adhesive layer 3. The proportion is, for example, 20% by mass or less, preferably 10% by mass or less, from the viewpoints of adjusting the glass transition temperature of the acrylic polymer and avoiding the risk of corrosion of the adherend 2 by acid.

[0048] The monomer component may contain other copolymerizable monomers, such as acid anhydride monomers, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, epoxy group-containing monomers, cyano group-containing monomers, amide group-containing monomers, monomers having a succinimide skeleton, maleimides, itaconimides, alkoxy group-containing monomers, vinyl esters, vinyl ethers, and aromatic vinyl compounds.

[0049] Acid anhydride monomers include, for example, maleic anhydride and itaconic anhydride.

[0050] Examples of sulfonic acid group-containing monomers include styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid.

[0051] An example of a phosphate group-containing monomer is 2-hydroxyethyl acryloyl phosphate.

[0052] Examples of epoxy group-containing monomers include epoxy group-containing acrylates such as glycidyl (meth)acrylate and 2-ethyl (meth)acrylate glycidyl ether, allyl glycidyl ether, and glycidyl ether (meth)acrylate.

[0053] Cyano group-containing monomers include, for example, acrylonitrile and methacrylonitrile.

[0054] Examples of amide group-containing monomers include N-vinylcarboxylic acid amides, N-hydroxyalkyl(meth)acrylamides, N-alkoxyalkyl(meth)acrylamides, N,N-dimethylaminopropyl(meth)acrylamide, and N-(meth)acryloylmorpholine.

[0055] Examples of N-vinylcarboxylic acid amides include (meth)acrylamide, N,N-dialkyl(meth)acrylamide, N-alkyl(meth)acrylamide, and N-vinylacetamide.

[0056] Examples of N,N-dialkyl(meth)acrylamides include N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N,N-di(n-butyl)(meth)acrylamide, and N,N-di(t-butyl)(meth)acrylamide.

[0057] Examples of N-alkyl(meth)acrylamides include N-ethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, and Nn-butyl(meth)acrylamide.

[0058] Examples of N-hydroxyalkyl(meth)acrylamides include N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxypropyl)(meth)acrylamide, N-(1-hydroxypropyl)(meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(2-hydroxybutyl)(meth)acrylamide, N-(3-hydroxybutyl)(meth)acrylamide, and N-(4-hydroxybutyl)(meth)acrylamide. Examples of N-alkoxyalkyl(meth)acrylamides include N-methoxymethyl(meth)acrylamide, N-methoxyethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide.

[0059] Examples of monomers having a succinimide skeleton include N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, and N-(meth)acryloyl-8-oxyhexamethylene succinimide.

[0060] Examples of maleimides include N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide.

[0061] Examples of itaconimides include N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide.

[0062] Examples of alkoxy group-containing monomers include alkoxyalkyl (meth)acrylates and alkoxyalkylene glycol (meth)acrylates. Examples of alkoxyalkyl (meth)acrylates include 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and ethoxypropyl (meth)acrylate. Examples of alkoxyalkylene glycol (meth)acrylates include methoxyethylene glycol (meth)acrylate and methoxypolypropylene glycol (meth)acrylate.

[0063] Vinyl esters include, for example, vinyl acetate and vinyl propionate.

[0064] Examples of vinyl ethers include methyl vinyl ether and ethyl vinyl ether.

[0065] Examples of aromatic vinyl compounds include styrene, α-methylstyrene, and vinyltoluene. Examples of olefins include ethylene, butadiene, isoprene, and isobutylene.

[0066] The copolymerizable monomers may be used alone or in combination of two or more kinds.

[0067] The acrylic polymer can be formed by polymerizing the above-mentioned monomer components. Examples of the polymerization method include solution polymerization, bulk polymerization, and emulsion polymerization, with solution polymerization being preferred. In solution polymerization, for example, a reaction solution is prepared by blending the monomer components and a polymerization initiator in a solvent, and then the reaction solution is heated. Then, an acrylic polymer solution containing an acrylic polymer can be obtained by undergoing a polymerization reaction of the monomer components in the reaction solution.

[0068] The polymerization initiator may be, for example, a thermal polymerization initiator. The amount of the polymerization initiator used is, for example, 0.05 parts by mass or more, or, for example, 1 part by mass or less, relative to 100 parts by mass of the monomer components.

[0069] Examples of the thermal polymerization initiator include azo-based polymerization initiators and peroxide-based polymerization initiators. Examples of the azo-based polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid) dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, and 2,2'-azobis(N,N'-dimethyleneisobutylamidine) dihydrochloride. Examples of the peroxide polymerization initiator include dibenzoyl peroxide, t-butyl permaleate, and lauroyl peroxide. Examples of the thermal polymerization initiator include preferably an azo polymerization initiator, more preferably 2,2'-azobisisobutyronitrile.

[0070] The weight-average molecular weight of the acrylic polymer is, from the viewpoint of ensuring cohesive strength in the pressure-sensitive adhesive layer 3, for example, 100,000 or more, preferably 300,000 or more, and more preferably 500,000 or more. The weight-average molecular weight is, for example, 5,000,000 or less, preferably 3,000,000 or less, more preferably 2,000,000 or less, even more preferably 1,000,000, and particularly preferably 800,000 or less. The weight-average molecular weight of the acrylic polymer is measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

[0071] The glass transition temperature (Tg) of the base polymer is, for example, 0° C. or lower, preferably −10° C. or lower, and more preferably −20° C. or lower. The glass transition temperature is, for example, −80° C. or higher.

[0072] The glass transition temperature (Tg) of a polymer can be determined by the theoretical glass transition temperature (theoretical value) calculated based on the Fox equation below. The Fox equation is a relationship between the glass transition temperature (Tg) of a polymer and the glass transition temperature (Tgi) of a homopolymer of the monomers constituting the polymer. In the Fox equation below, Tg represents the glass transition temperature (°C) of the polymer, Wi represents the weight fraction of the monomer i constituting the polymer, and Tgi represents the glass transition temperature (°C) of the homopolymer formed from the monomer i. The glass transition temperature of a homopolymer can be determined by literature values. For example, the glass transition temperatures of various homopolymers are listed in "Polymer Handbook" (4th edition, John Wiley & Sons, Inc., 1999) and "New Polymer Library 7: Introduction to Synthetic Resins for Paints" (Kiyozo Kitaoka, Polymer Publishing Association, 1995). Meanwhile, the glass transition temperature of a homopolymer of a monomer can also be determined by the method specifically described in JP 2007-51271 A. Fox formula 1 / (273+Tg)=Σ[Wi / (273+Tgi)] Examples of compounds that develop color upon reaction with an acid (color-forming compounds) include leuco dyes, triarylmethane dyes, diphenylmethane dyes, fluoran dyes, spiropyran dyes, and rhodamine dyes. The color-forming compounds may be used alone or in combination of two or more.

[0073] Examples of leuco dyes include 2'-anilino-6'-(N-ethyl-N-isopentylamino)-3'-methylspiro[phthalide-3,9'-[9H]xanthene], 3-dibutylamino-6-methyl-7-anilinofluoran, 3-dipropylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-dimethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-xylidinofluoran, and 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide.

[0074] An example of a triarylmethane dye is p,p',p"-tris-dimethylaminotriphenylmethane. An example of a diphenylmethane dye is 4,4-bis-dimethylaminophenylbenzhydrylbenzyl ether. An example of a fluoran dye is 3-diethylamino-6-methyl-7-chlorofluoran. An example of a spiropyran dye is 3-methylspirodinaphthopyran. An example of a rhodamine dye is rhodamine-B-anilinolactam.

[0075] In order to ensure good black coloring in the adhesive layer 3, the color-forming compound is preferably a leuco dye, more preferably 2'-anilino-6'-(N-ethyl-N-isopentylamino)-3'-methylspiro[phthalide-3,9'-[9H]xanthene].

[0076] The amount of the color-forming compound per 100 parts by mass of the base polymer is, for example, 0.5 parts by mass or more, preferably 1 part by mass or more, and for example, 10 parts by mass or less, preferably 7 parts by mass or less, more preferably 5 parts by mass or less.

[0077] The acid generator used is preferably a photoacid generator that generates acid when irradiated with active energy rays. In this case, the pressure-sensitive adhesive layer 3 can change color in a portion irradiated with active energy rays as an external stimulus. Specifically, in the portion of the pressure-sensitive adhesive layer 3 irradiated with active energy rays, acid is generated from the photoacid generator, and this acid causes the color-forming compound to develop a color. The portion of the pressure-sensitive adhesive layer 3 irradiated with active energy rays is colored, for example, a black color, depending on the color developed by the color-forming compound. The type of active energy ray used as the external stimulus is determined by the type of photoacid generator (specifically, the wavelength of the active energy ray at which the photoacid generator generates an acid). Examples of active energy rays include ultraviolet light, visible light, infrared light, X-rays, α-rays, β-rays, and γ-rays. From the viewpoints of the versatility of equipment used and ease of handling, ultraviolet light is preferably used as the active energy ray.

[0078] Examples of photoacid generators include onium compounds that generate acid upon irradiation with ultraviolet light. The onium compounds are provided in the form of onium salts of onium cations and anions. Examples of onium cations include iodonium and sulfonium. Examples of anions include Cl. - , Br - , I - , ZnCl3 - , HSO3 - , BF4 - , PF6 - , AsF6 - , SbF6 - , CH3SO3 - , CF3SO3 - , C4F9HSO3 - , (C6F5)4B - , and (C4H9)4B - The photoacid generator may be used alone or in combination of two or more. The photoacid generator is preferably a sulfonium compound and (C6F5)4B - Onium salts (onium compounds) consisting of sulfonium and C4F9HSO3 - Examples of suitable onium salts (onium compounds) include:

[0079] The amount of the acid generator blended per 100 parts by mass of the base polymer is, for example, 1 part by mass or more, preferably 2 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 6 parts by mass or more, and for example, 20 parts by mass or less, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less.

[0080] The amount of the acid generator to be blended relative to 100 parts by mass of the color-forming compound is, for example, 100 parts by mass or more, preferably 200 parts by mass or more, more preferably 300 parts by mass or more, and even more preferably 330 parts by mass or more, and is, for example, 1000 parts by mass or less, preferably 700 parts by mass or less, and more preferably 500 parts by mass or less.

[0081] The pressure-sensitive adhesive composition may also contain a crosslinking agent from the viewpoint of introducing a crosslinked structure into the base polymer. Examples of crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, carbodiimide crosslinking agents, and metal chelate crosslinking agents. The crosslinking agents may be used alone or in combination of two or more.

[0082] Examples of isocyanate crosslinking agents include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and polymethylene polyphenylisocyanate. Also included as isocyanate crosslinking agents are derivatives of these isocyanates. Examples of isocyanate derivatives include isocyanurate-modified products and polyol-modified products. Commercially available isocyanate crosslinking agents include, for example, Coronate L (a trimethylolpropane adduct of tolylene diisocyanate, manufactured by Tosoh), Coronate HL (a trimethylolpropane adduct of hexamethylene diisocyanate, manufactured by Tosoh), Coronate HX (an isocyanurate of hexamethylene diisocyanate, manufactured by Tosoh), and Takenate D110N (a trimethylolpropane adduct of xylylene diisocyanate, manufactured by Mitsui Chemicals).

[0083] Examples of epoxy crosslinking agents include bisphenol A, epichlorohydrin-type epoxy resins, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diamine glycidylamine, N,N,N',N'-tetraglycidyl-m-xylylenediamine, and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0084] The crosslinking agent preferably includes an isocyanate crosslinking agent and an epoxy crosslinking agent, and more preferably includes a trimethylolpropane adduct of xylylene diisocyanate and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0085] The amount of crosslinking agent blended is, for example, 0.01 parts by mass or more, and preferably 0.03 parts by mass or more, per 100 parts by mass of the base polymer, from the viewpoint of ensuring the cohesive strength of the pressure-sensitive adhesive layer 3. From the viewpoint of ensuring good tackiness in the pressure-sensitive adhesive layer 3, the amount of crosslinking agent blended is, for example, 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 1 part by mass or less, per 100 parts by mass of the base polymer.

[0086] When a crosslinked structure is introduced into the base polymer, a crosslinking catalyst may be used to effectively promote the crosslinking reaction. Examples of the crosslinking catalyst include metal-based crosslinking catalysts. Examples of the metal-based crosslinking catalyst include dibutyltin dilaurate, tetra-n-butyl titanate, tetraisopropyl titanate, nursem ferric iron, and butyltin oxide. The amount of the crosslinking catalyst used is, for example, 0.0001 parts by mass or more per 100 parts by mass of the base polymer. The amount used is, for example, 1 part by mass or less.

[0087] In addition, when an isocyanate crosslinking agent (specifically, a trimethylolpropane adduct of xylylene diisocyanate) is blended as the crosslinking agent and a metal-based crosslinking catalyst (specifically, dibutyltin dilaurate) is blended as the crosslinking catalyst, it is preferable to blend acetylacetone as a crosslinking inhibitor into the adhesive composition.

[0088] When acetylacetone is added, it coordinates with dibutyltin dilaurate. This makes it possible to suppress the progress of the crosslinking reaction before the pressure-sensitive adhesive composition is applied to a release film (first release film 11) to form a coating film. Furthermore, as will be described in detail later, by heating and drying the composition when forming the coating film, the acetylacetone can be removed and the crosslinking reaction can proceed.

[0089] The amount of acetylacetone used is, for example, 100 parts by mass or more, preferably 10,000 parts by mass or more, and for example, 50,000 parts by mass or less, relative to 100 parts by mass of the crosslinking catalyst.

[0090] The pressure-sensitive adhesive composition may also contain other components as needed, such as a polymerizable compound and its cured product, a photopolymerization initiator, a silane coupling agent, a tackifier, a plasticizer, a softener, an antioxidant, a surfactant, and an antistatic agent.

[0091] Examples of the polymerizable compound include a monomer (monofunctional monomer) having one polymerizable functional group (ethylenically unsaturated double bond) and a monomer (polyfunctional monomer) having multiple polymerizable functional groups. Examples of the monofunctional monomer include monofunctional (meth)acrylate. Examples of the polyfunctional monomer include polyfunctional (meth)acrylate.

[0092] In addition, when the pressure-sensitive adhesive composition contains a polymerizable compound, the pressure-sensitive adhesive composition preferably further contains a photopolymerization initiator.

[0093] The adhesive composition is obtained by blending a base polymer, a compound that develops color upon reaction with an acid, an acid generator, a crosslinking agent that is optionally blended, a crosslinking catalyst that is optionally blended, acetylacetone that is optionally blended, and other components that are optionally blended in the above-mentioned ratios.

[0094] The pressure-sensitive adhesive layer 3 is formed from a pressure-sensitive adhesive composition by the method described below.

[0095] The adhesive layer 3 can be changed in color by an external stimulus.

[0096] Specifically, when the pressure-sensitive adhesive composition contains a photoacid generator, when the pressure-sensitive adhesive layer 3 is irradiated with active energy rays as an external stimulus, an acid is generated from the photoacid generator, and the color-forming compound develops color by reacting with the acid, thereby causing the pressure-sensitive adhesive layer 3 to change color (the pressure-sensitive adhesive layer 3 has a reduced visible light transmittance at a wavelength of 550 nm).

[0097] The pressure-sensitive adhesive layer 3 has a discolored portion 10 that has changed color due to an external stimulus. More specifically, the pressure-sensitive adhesive layer 3 has the discolored portion 10 in at least a portion of the pressure-sensitive adhesive layer 3. Preferably, the pressure-sensitive adhesive layer 3 has the discolored portion 10 in a portion of the pressure-sensitive adhesive layer 3. The visible light transmittance of the discolored portion 10 at a wavelength of 550 nm is, for example, less than 20%.

[0098] The thickness of the pressure-sensitive adhesive layer 3 is, for example, 10 μm or more, or preferably 15 μm or more, from the viewpoint of ensuring sufficient adhesiveness to the adherend 2. From the viewpoint of handleability, the thickness of the pressure-sensitive adhesive layer 3 is, for example, 300 μm or less, preferably 100 μm or less, or more preferably 50 μm or less.

[0099] 4.Oxygen barrier layer The oxygen barrier layer 4 has an oxygen permeability equal to or lower than a predetermined value, and therefore, the oxygen barrier layer 4 can prevent oxygen from penetrating into the pressure-sensitive adhesive layer 3. As a result, as will be described in detail later, deterioration of the discolored portion 10 due to external light can be prevented.

[0100] Specifically, the oxygen permeability of the oxygen barrier layer 4 is 200 cm 3 / m 2 ·day·atm or less, preferably 150cm 3 / m 2 ·day·atm or less, preferably 50cm 3 / m 2 ·day·atm or less, more preferably 20cm 3 / m 2 The oxygen permeability is, for example, 1 cm 3 / m 2 ·day·atm or more.

[0101] When the oxygen permeability of the oxygen barrier layer 4 is equal to or lower than the upper limit, it is possible to prevent oxygen from penetrating into the pressure-sensitive adhesive layer 3. As a result, it is possible to prevent deterioration of the discolored portion 10 due to external light.

[0102] The oxygen permeability of the oxygen barrier layer 4 can be adjusted to the above range by adjusting the material of the polymer film (in other words, the type of oxygen barrier layer 4) described later and / or the thickness of the oxygen barrier layer 4 described later.

[0103] The oxygen permeability of the oxygen barrier layer 4 can be measured in accordance with JIS K7126-2 Appendix A at 23°C and a relative humidity of 55%.

[0104] The oxygen barrier layer 4 is, for example, a transparent polymer film. Examples of materials for the polymer film include polyester resin, (meth)acrylic resin (acrylic resin and / or methacrylic resin), olefin resin, polycarbonate resin, polyethersulfone resin, polyarylate resin, melamine resin, polyamide resin, polyimide resin, cellulose resin, and polystyrene resin.

[0105] Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, preferably polyethylene terephthalate (PET). Examples of (meth)acrylic resins include polymethacrylate. Examples of olefin resins include polyethylene, polypropylene, and cycloolefin polymer (COP).

[0106] As the material for the polymer film, polyester resin and (meth)acrylic resin are preferred from the viewpoint of adjusting the oxygen permeability of the oxygen barrier layer 4 to the above range.

[0107] The polymer film materials may be used alone or in combination of two or more kinds.

[0108] Furthermore, the oxygen barrier layer 4 can also be a film formed from a biomass-derived component (for example, isosorbide).

[0109] Furthermore, in the second step of the method for producing the laminate 1 described below, when active energy rays are irradiated from the oxygen barrier layer 4 side, an oxygen barrier layer that transmits active energy rays is selected as the oxygen barrier layer 4.

[0110] An example of the oxygen barrier layer that transmits active energy rays is an oxygen barrier layer that transmits ultraviolet rays.

[0111] Examples of oxygen barrier layers that transmit ultraviolet light include the transparent polymer films described above.

[0112] The oxygen barrier layer that transmits ultraviolet rays has a total light transmittance (JIS K 7375-2008) of, for example, 80% or more, or preferably 85% or more.

[0113] The oxygen barrier layer 4 has a thickness of, for example, 10 μm or more, preferably 22 μm or more, more preferably 30 μm or more, and for example, 200 μm or less, preferably 100 μm or less.

[0114] 5. Manufacturing method of laminate The method for producing the laminate comprises a first step of arranging a pressure-sensitive adhesive layer 3 on one surface in the thickness direction of an adherend 2, a second step of forming a discolored portion 10 in the pressure-sensitive adhesive layer 3 by an external stimulus, and a third step of arranging an oxygen barrier layer 4 on one surface in the thickness direction of the pressure-sensitive adhesive layer 3. Below, the method for producing the laminate 1 will be explained in order of each step.

[0115] Specifically, the first method and the second method are mentioned.

[0116] The first method is a method in which the pressure-sensitive adhesive layer 3 is disposed on one surface of the adherend 2 in the thickness direction before the discolored portion 10 is formed in the pressure-sensitive adhesive layer 3.

[0117] The second method is a method in which, after forming discolored portion 10 in pressure-sensitive adhesive layer 3, pressure-sensitive adhesive layer 3 is disposed on one surface of adherend 2 in the thickness direction.

[0118] 5-1. 1st method In the first method, before forming discolored portion 10 in adhesive layer 3, adhesive layer 3 is placed on one surface in the thickness direction of adherend 2. That is, in the first method, adhesive layer 3 is placed on one surface in the thickness direction of adherend 2, and then discolored portion 10 is formed in adhesive layer 3. Because adhesive layer 3 is transparent when placed, it can be properly inspected for the presence of foreign matter and air bubbles.

[0119] Specifically, Method 1 includes Method 1A, Method 1B, and Method 1C. Method 1A involves carrying out Step 1, Step 2, and Step 3 in this order. Method 1B involves carrying out Step 3, Step 1, and Step 2 in this order. Method 1C involves carrying out Step 1, Step 3, and Step 2 in this order.

[0120] <Method 1A> In Method 1A, the first step, the second step, and the third step are carried out in this order.

[0121] In the first step, a pressure-sensitive adhesive layer 3 is disposed on one surface of an adherend 2 in the thickness direction.

[0122] To dispose the pressure-sensitive adhesive layer 3 on one surface in the thickness direction of the adherend 2, first, the adherend 2 is prepared as shown in FIG. 2A.

[0123] Next, the pressure-sensitive adhesive layer 3 is prepared.

[0124] The pressure-sensitive adhesive layer 3 can be prepared, for example, by applying the above-mentioned pressure-sensitive adhesive composition onto a release film (first release film 11) to form a coating film, and then drying the coating film.

[0125] The release film may be, for example, a flexible plastic film. Examples of the plastic film include a polyethylene terephthalate film, a polyethylene film, a polypropylene film, and a polyester film. The thickness of the release film is, for example, 3 μm or more. The thickness is, for example, 200 μm or less. The surface of the release film is preferably subjected to a release treatment.

[0126] Examples of methods for applying the pressure-sensitive adhesive composition include roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, and die coating. The drying temperature of the coating film is, for example, 50°C or higher. The drying temperature is, for example, 200°C or lower. The drying time is, for example, 5 seconds or longer. The drying time is, for example, 20 minutes or shorter.

[0127] When the pressure-sensitive adhesive composition contains a crosslinking agent, a crosslinking reaction proceeds simultaneously with the drying or by subsequent aging. The aging conditions are appropriately set depending on the type of crosslinking agent. The aging temperature is, for example, 20°C or higher. The aging temperature is, for example, 160°C or lower. The aging time is, for example, 1 minute or longer. The aging time is, for example, 7 days or shorter.

[0128] Furthermore, when the pressure-sensitive adhesive composition contains acetylacetone (in other words, when acetylacetone is coordinated with dibutyltin dilaurate), the acetylacetone coordinated with dibutyltin dilaurate is removed during drying, thereby allowing the crosslinking reaction to proceed.

[0129] Furthermore, before or after aging, a further release film (second release film) may be laminated on the pressure-sensitive adhesive layer 3 on the first release film 11. The second release film is, for example, a flexible plastic film that has been subjected to a surface release treatment. As the second release film, the same films as those described above for the first release film 11 can be used.

[0130] In this manner, a pressure-sensitive adhesive layer 3 can be produced in which the adhesive surface is covered and protected by a release film. Each release film is peeled off from the pressure-sensitive adhesive layer 3 as necessary when the pressure-sensitive adhesive layer 3 is to be used.

[0131] 2B, this pressure-sensitive adhesive layer 3 is transferred to one surface in the thickness direction of the adherend 2. In this way, the pressure-sensitive adhesive layer 3 is disposed on one surface in the thickness direction of the adherend 2.

[0132] In the second step, as shown in FIG. 2C, a discolored portion 10 is formed in the adhesive layer 3 by an external stimulus.

[0133] Specifically, the pressure-sensitive adhesive layer 3 is irradiated with active energy rays as an external stimulus from the pressure-sensitive adhesive layer 3 side and / or the adherend 2 side through a mask pattern (not shown) for masking predetermined regions of the pressure-sensitive adhesive layer 3. This causes discoloration of the portions of the pressure-sensitive adhesive layer 3 that are not masked by the mask pattern.

[0134] In this step, an acid is generated from the photoacid generator in the area of ​​the pressure-sensitive adhesive layer 3 that has been irradiated with active energy rays, and the color-forming compound reacts with the acid to develop color, thereby forming a discolored area 10 in the pressure-sensitive adhesive layer 3.

[0135] 2D, in the third step, an oxygen barrier layer 4 is disposed on one surface in the thickness direction of the pressure-sensitive adhesive layer 3. In this way, a laminate 1 is obtained.

[0136] <Method 1B> In Method 1B, the third step, the first step and the second step are carried out in this order.

[0137] In the third step, the oxygen barrier layer 4 is disposed on one thickness-wise surface of the pressure-sensitive adhesive layer 3. To dispose the oxygen barrier layer 4 on one thickness-wise surface of the pressure-sensitive adhesive layer 3, first, as shown in Fig. 3A, the pressure-sensitive adhesive layer 3 is formed on the first release film 11 by the method described above.

[0138] 3B, the oxygen barrier layer 4 is disposed on one thickness-wise surface of the pressure-sensitive adhesive layer 3. This results in a color-changeable adhesive sheet S having the first release film 11, the pressure-sensitive adhesive layer 3, and the oxygen barrier layer 4 in this order.

[0139] 3C, in the first step, the pressure-sensitive adhesive layer 3 is placed on one surface in the thickness direction of the adherend 2. Specifically, the first release film 11 is peeled off from the pressure-sensitive adhesive layer 3, and the pressure-sensitive adhesive layer 3 is placed on one surface in the thickness direction of the adherend 2.

[0140] 3D, in the second step, active energy rays are irradiated from the oxygen barrier layer 4 side and / or the adherend 2 side in the same manner as above to form discolored portions 10 in the pressure-sensitive adhesive layer 3. In this way, a laminate 1 is obtained. <Method 1C> In Method 1C, the first step, the third step, and the second step are carried out in this order.

[0141] In the first step, the pressure-sensitive adhesive layer 3 is disposed on one surface of the adherend 2 in the thickness direction using the same method as above.

[0142] Specifically, first, an adherend 2 is prepared as shown in Fig. 4A. Next, a pressure-sensitive adhesive layer 3 is prepared on a first release film 11 using the same method as above. Next, as shown in Fig. 4B, the pressure-sensitive adhesive layer 3 is transferred to one surface in the thickness direction of the adherend 2 using the same method as above. In this way, the pressure-sensitive adhesive layer 3 is disposed on one surface in the thickness direction of the adherend 2.

[0143] In the third step, as shown in FIG. 4C, an oxygen barrier layer 4 is disposed on one surface of the pressure-sensitive adhesive layer 3 in the thickness direction.

[0144] 4D, in the second step, active energy rays are irradiated from the oxygen barrier layer 4 side and / or the adherend 2 side in the same manner as above to form discolored portions 10 in the pressure-sensitive adhesive layer 3. In this way, a laminate 1 is obtained.

[0145] 5-2.Second method In the second method, after forming discolored portion 10 in pressure-sensitive adhesive layer 3, pressure-sensitive adhesive layer 3 is placed on one thickness-wise surface of adherend 2. Therefore, in the second method, discolored portion 10 can be formed in pressure-sensitive adhesive layer 3 without applying an external stimulus to adherend 2.

[0146] Specifically, the second method includes a second method, a second method, a first method, and a third method. In the second method, the second step, the first step, and the third step are carried out in this order. In the second method, the second step, the third step, and the first step are carried out in this order. In the second method, the third step, the second step, and the first step are carried out in this order.

[0147] <Method 2A> In Method 2A, the second step, the first step and the third step are carried out in this order.

[0148] In the second step, a discolored portion 10 is formed in the adhesive layer 3 by an external stimulus.

[0149] To form discolored portion 10 in pressure-sensitive adhesive layer 3 by an external stimulus, first, as shown in Fig. 5A, pressure-sensitive adhesive layer 3 is prepared on first release film 11 by the same method as above. Next, as shown in Fig. 5B, active energy rays are irradiated from the pressure-sensitive adhesive layer 3 side and / or the first release film 11 side by the same method as above, to form discolored portion 10 in pressure-sensitive adhesive layer 3.

[0150] 5C, in the first step, the pressure-sensitive adhesive layer 3 is placed on one surface in the thickness direction of the adherend 2. Specifically, the first release film 11 is peeled off from the pressure-sensitive adhesive layer 3, and the pressure-sensitive adhesive layer 3 is placed on one surface in the thickness direction of the adherend 2.

[0151] 5D, in the third step, an oxygen barrier layer 4 is disposed on one surface in the thickness direction of the pressure-sensitive adhesive layer 3. In this way, a laminate 1 is obtained.

[0152] <Method 2B> In Method 2B, the second step, the third step and the first step are carried out in this order.

[0153] In the second step, a discolored portion 10 is formed in the adhesive layer 3 by an external stimulus.

[0154] To form discolored portion 10 in pressure-sensitive adhesive layer 3 by an external stimulus, first, as shown in Fig. 6A, pressure-sensitive adhesive layer 3 is prepared on first release film 11 by the same method as above. Next, as shown in Fig. 6B, active energy rays are irradiated from the pressure-sensitive adhesive layer 3 side and / or the first release film 11 side by the same method as above, to form discolored portion 10 in pressure-sensitive adhesive layer 3.

[0155] In the third step, as shown in FIG. 6C, an oxygen barrier layer 4 is disposed on one surface of the pressure-sensitive adhesive layer 3 in the thickness direction.

[0156] In the first step, as shown in Fig. 6D, the pressure-sensitive adhesive layer 3 is disposed on one surface in the thickness direction of the adherend 2. Specifically, the first release film 11 is peeled off from the pressure-sensitive adhesive layer 3, and the pressure-sensitive adhesive layer 3 is disposed on one surface in the thickness direction of the adherend 2. In this way, the laminate 1 is obtained.

[0157] <Method 2C> In the 2C method, the third step, the second step, and the first step are carried out in this order.

[0158] In the third step, the oxygen barrier layer 4 is disposed on one thickness-wise surface of the pressure-sensitive adhesive layer 3. To dispose the oxygen barrier layer 4 on one thickness-wise surface of the pressure-sensitive adhesive layer 3, first, as shown in Fig. 7A, the pressure-sensitive adhesive layer 3 is formed on the first release film 11 by the method described above.

[0159] 7B, the oxygen barrier layer 4 is disposed on one thickness-wise surface of the pressure-sensitive adhesive layer 3. This results in a color-changeable adhesive sheet S having the first release film 11, the pressure-sensitive adhesive layer 3, and the oxygen barrier layer 4 in this order.

[0160] In the second step, a discolored portion 10 is formed in the adhesive layer 3 by an external stimulus.

[0161] To form a discolored area 10 in the adhesive layer 3 by an external stimulus, as shown in Figure 7C, active energy rays are irradiated from the oxygen barrier layer 4 side and / or the first release film 11 side in the same manner as described above, thereby forming a discolored area 10 in the adhesive layer 3.

[0162] In the first step, as shown in Fig. 7D, the pressure-sensitive adhesive layer 3 is disposed on one surface in the thickness direction of the adherend 2. Specifically, the first release film 11 is peeled off from the pressure-sensitive adhesive layer 3, and the pressure-sensitive adhesive layer 3 is disposed on one surface in the thickness direction of the adherend 2. In this way, the laminate 1 is obtained.

[0163] 6. Effects The laminate 1 has an oxygen permeability of 200 cm 3 / m 2 The oxygen barrier layer 4 has a temperature of 100°C / day atm or less, which can prevent deterioration of the discolored portion 10 due to external light.

[0164] Specifically, when the discolored portion 10 is exposed to oxygen, deterioration of the discolored portion 10 due to external light is accelerated. On the other hand, the laminate 1 has an oxygen permeability of 200 cm 3 / m 2 The pressure-sensitive adhesive layer 3 has an oxygen barrier layer 4 with a viscosity of 100 ppm or less per day, thereby preventing oxygen from penetrating the pressure-sensitive adhesive layer 3. As a result, deterioration of the discolored portion 10 due to external light can be prevented.

[0165] The method for producing the laminate 1 is to form a film having an oxygen permeability of 200 cm on one surface of the pressure-sensitive adhesive layer 3 in the thickness direction. 3 / m 2 The method further includes a third step of disposing an oxygen barrier layer 4 having an oxygen barrier property of 1000 ppm or less. This makes it possible to manufacture a laminate 1 that can suppress deterioration of discolored portion 10 due to external light.

[0166] 7. Variations Next, modified examples of the embodiment will be described. In the following modified examples, the same components and steps as those in the above-described embodiment will be denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, the modified examples can be combined as appropriate. Furthermore, the modified examples can achieve the same effects as those in the embodiment, unless otherwise specified.

[0167] In the above description, the external stimulus is active energy rays, but the external stimulus may also be heat.

[0168] In the above explanation, the pressure-sensitive adhesive layer 3 is prepared on the upper surface of the release film 11, and then the pressure-sensitive adhesive layer 3 is transferred (placed) on the adherend 2. On the other hand, it is also possible to apply the pressure-sensitive adhesive composition directly to the adherend 2 without preparing the pressure-sensitive adhesive layer 3 on the upper surface of the release film 11, and then place the pressure-sensitive adhesive layer 3 on the adherend 2.

[0169] In the above description, the laminate 1 includes the adherend 2, the pressure-sensitive adhesive layer 3, and the oxygen barrier layer 4, arranged in this order toward one side in the thickness direction. The laminate 1 may further include an active energy ray-blocking layer 5. Specifically, the laminate 1 may further include an active energy ray-blocking layer 5 on one surface in the thickness direction of the oxygen barrier layer 4 and / or on the other surface in the thickness direction of the oxygen barrier layer 4. More specifically, as shown in FIG. 8A , the laminate 1 may further include an active energy ray-blocking layer 5 on one surface in the thickness direction of the oxygen barrier layer 4. Furthermore, as shown in FIG. 8B , the laminate 1 may further include an active energy ray-blocking layer 5 on the other surface in the thickness direction of the oxygen barrier layer 4. Furthermore, as shown in FIG. 8C , the laminate 1 may further include an active energy ray-blocking layer 5 on one surface in the thickness direction of the oxygen barrier layer 4 and on the other surface in the thickness direction of the oxygen barrier layer 4.

[0170] When the laminate 1 includes the active energy ray-blocking layer 5, further discoloration of the discolored portion 10 due to active energy rays can be suppressed.

[0171] The active energy ray blocking layer 5 may be, for example, an ultraviolet ray blocking layer.

[0172] The ultraviolet blocking layer is a layer that blocks (absorbs or reflects) ultraviolet rays. When the laminate 1 is provided with an ultraviolet blocking layer, further discoloration of the discolored portion 10 due to ultraviolet rays can be suppressed.

[0173] Specific examples of the ultraviolet blocking layer include an ultraviolet absorbing layer and an ultraviolet reflecting layer.

[0174] Examples of the ultraviolet absorbing layer include a resin film containing an ultraviolet absorbing agent and an adhesive tape containing an ultraviolet absorbing agent.

[0175] The average transmittance of the ultraviolet absorbing layer in the wavelength range of 300 nm or more and 400 nm or less is, for example, 15% or less, or preferably 10% or less.

[0176] The ultraviolet reflective layer is a layer that reflects ultraviolet light by utilizing light scattering, and examples of the ultraviolet reflective layer include multilayer optical films.

[0177] The active energy ray-blocking layer 5 is disposed on the other surface in the thickness direction of the oxygen barrier layer 4 and / or on the other surface in the thickness direction of the oxygen barrier layer 4 via, for example, a known adhesive.

[0178] Furthermore, in the above-described method for producing the laminate 1, there is no particular limitation on the timing of disposing the active energy ray-blocking layer 5. When the second step of forming discolored portion 10 in the pressure-sensitive adhesive layer 3 by ultraviolet light is carried out after disposing an ultraviolet blocking layer as the active energy ray-blocking layer 5, the discolored portion 10 is formed in the pressure-sensitive adhesive layer 3 by irradiating with ultraviolet light from the side opposite to the ultraviolet blocking layer.

[0179] The active energy ray-blocking layer 5 has a thickness of, for example, 10 μm or more, or preferably 50 μm or more, and for example, 1000 μm or less, or preferably 300 μm or less.

[0180] The laminate 1 may further include a substrate 20. The position of the substrate 20 in the laminate 1 is not particularly limited.

[0181] The substrate 20 is, for example, a flexible plastic film. Examples of materials constituting the plastic film include polyolefin, polyester, polyamide, polyimide, polyvinyl chloride, polyvinylidene chloride, cellulose, polystyrene, and polycarbonate. Examples of polyolefins include polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-vinyl alcohol copolymer. Examples of polyesters include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Examples of polyamides include polyamide 6, polyamide 6,6, and partially aromatic polyamide.

[0182] The laminate 1 may further include an intermediate layer 30. The position of the intermediate layer 30 in the laminate 1 is not particularly limited.

[0183] As the intermediate layer 30, for example, the same materials as those exemplified for the adherend 2, the oxygen barrier layer 4, and the substrate 20 can be used.

[0184] Examples of the intermediate layer 30 include an adhesive layer formed from a known adhesive, an optical film, and various functional layers.

[0185] As described above, the laminate 1 can further include at least one selected from the group consisting of the active energy ray-blocking layer 5, the substrate 20, and the intermediate layer 30.

[0186] A specific example of such a case is a laminate 1 having an adherend 2, a pressure-sensitive adhesive layer 3, an intermediate layer 30, an active energy ray-blocking layer 5, and an oxygen barrier layer 4 in that order toward one side in the thickness direction, as shown in Figure 9A.

[0187] Another specific example is a laminate 1 having an adherend 2, a pressure-sensitive adhesive layer 3, a substrate 20, an active energy ray-blocking layer 5, and an oxygen barrier layer 4 in that order toward one side in the thickness direction, as shown in Figure 9B.

[0188] Another specific example is a laminate 1 having an adherend 2, a pressure-sensitive adhesive layer 3, an oxygen barrier layer 4, an active energy ray-blocking layer 5, and a substrate 20 in that order toward one side in the thickness direction, as shown in Figure 9C.

[0189] As a specific example, as shown in FIG. 9D, there is a laminate 1 having an adherend 2, a pressure-sensitive adhesive layer 3, an intermediate layer 30, a substrate 20, an active energy ray-blocking layer 5, and an oxygen barrier layer 4 in that order toward one side in the thickness direction.

[0190] As a specific example, as shown in FIG. 9E, there is a laminate 1 having an adherend 2, a pressure-sensitive adhesive layer 3, an intermediate layer 30, an active energy ray-blocking layer 5, an oxygen barrier layer 4, and a substrate 20 arranged in this order toward one side in the thickness direction.

[0191] Furthermore, the laminate 1 may further include a surface protection layer 40 on the outermost surface (one surface in the thickness direction) of the laminate 1 from the viewpoint of surface protection.

[0192] The surface protection layer 40 may be, for example, a resin film.

[0193] An embodiment in which the laminate 1 includes the surface protective layer 40 will be described with reference to the laminate 1 shown in FIG. 9B.

[0194] 10, the surface protective layer 40 is disposed on the outermost surface (one thickness-wise surface of the oxygen barrier layer 4) of the laminate 1. That is, the laminate 1 includes, in order toward one thickness-wise side, an adherend 2, a pressure-sensitive adhesive layer 3, a substrate 20, an active energy ray-blocking layer 5, an oxygen barrier layer 4, and a surface protective layer 40.

[0195] In the above description of surface protection layer 40, the laminate 1 shown in Figure 9B was mentioned, but the same applies to other laminates (for example, the laminates shown in Figures 1, 8A to 8C, 9A, 9C and 9D).

[0196] 8. Color-changing adhesive sheet 11, the color-changeable adhesive sheet S comprises, in this order toward one side in the thickness direction, a first release film 11, an adhesive layer 3, and an oxygen barrier layer 4. More specifically, the color-changeable adhesive sheet S comprises a first release film 11, an adhesive layer 3 disposed directly on the upper surface (one surface in the thickness direction) of the first release film 11, and an oxygen barrier layer 4 disposed directly on the upper surface (one surface in the thickness direction) of the adhesive layer 3. When the oxygen barrier layer 4 is disposed directly on the upper surface (one surface in the thickness direction) of the adhesive layer 3, excellent oxygen barrier properties are achieved.

[0197] The variable color adhesive sheet S has an oxygen permeability of 200cm 3 / m 2 Therefore, the laminate 1 can be manufactured in such a way that deterioration of the discolored portion 10 due to external light can be suppressed.

[0198] The color-changeable adhesive sheet S may further include an active energy ray-blocking layer 5. Specifically, the color-changeable adhesive sheet S may include an active energy ray-blocking layer 5 on the other surface in the thickness direction of the adhesive layer 3 and / or on one surface in the thickness direction of the oxygen barrier layer 4 and / or on the other surface in the thickness direction of the oxygen barrier layer 4.

[0199] The active energy ray-blocking layer 5 is preferably an ultraviolet absorbing layer, more preferably an adhesive tape containing an ultraviolet absorbing agent. [Example]

[0200] The present invention will be described in detail below with reference to examples, but is not limited to these examples. The specific numerical values ​​of the blending amounts (contents), physical property values, parameters, etc. described below can be substituted for the upper limits (numeric values ​​defined as "not more than" or "less than") or lower limits (numeric values ​​defined as "not less than" or "exceeding") of the corresponding blending amounts (contents), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention."

[0201] <Preparation of base polymer> Manufacturing Example 1 In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, a mixture containing 95 parts by mass of n-butyl acrylate (BA), 5 parts by mass of acrylic acid (AA), 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 122 parts by mass of ethyl acetate as a solvent was stirred at 60°C for 7 hours under a nitrogen atmosphere (polymerization reaction). This resulted in a polymer solution containing an acrylic polymer. The weight-average molecular weight (Mw) of the acrylic polymer in this polymer solution was 600,000.

[0202] Manufacturing Example 2 In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, a mixture containing 63 parts by weight of 2-ethylhexyl acrylate (2EHA), 9 parts by weight of methyl methacrylate (MMA), 13 parts by weight of 2-hydroxyethyl acrylate (HEA), 15 parts by weight of N-vinyl-2-pyrrolidone (NVP), 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, and 233 parts by weight of ethyl acetate as a solvent was stirred at 60°C under a nitrogen atmosphere for 7 hours (polymerization reaction). This resulted in a polymer solution containing an acrylic polymer (polymer solution). The weight-average molecular weight (Mw) of the acrylic polymer in this polymer solution was 1.2 million.

[0203] Example 1 <Preparation of adhesive composition> The following components were uniformly mixed per 100 parts by mass of the acrylic polymer (base polymer) into the above polymer solution containing the acrylic polymer of Production Example 1 to prepare a pressure-sensitive adhesive composition. Compound that develops color upon reaction with acid: leuco dye, 2'-anilino-6'-(N-ethyl-N-isopentylamino)-3'-methylspiro[phthalide-3,9'-[9H]xanthene] (trade name: S-205, manufactured by Yamada Chemical Industry Co., Ltd.) 2 parts by mass Acid generator: Photoacid generator, sulfonium and (C6F5)4B - Onium salt of methyl methyl acrylate (product name: CPI-310B, manufactured by San-Apro Co., Ltd.) 7 parts by mass Crosslinking agent: epoxy-based crosslinking agent, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, Tetrad C (manufactured by Mitsubishi Gas Chemical Company, Inc.), 0.05 parts by mass (solid content equivalent)

[0204] <Production of adhesive layer> The adhesive composition was applied to a release film (polyester film, thickness 38 μm, Mitsubishi Plastics, Inc., MRF#38) with one release surface to form a coating film. The coating film was then dried at 132°C for 3 minutes to form a 25 μm thick adhesive layer. A 38 μm thick release film (polyester film, thickness 38 μm, Mitsubishi Plastics, Inc., MRF#38) with one polyester film release surface was then bonded to the adhesive layer. The resulting adhesive layer was then subjected to an aging treatment at 60°C for 1 day to promote a crosslinking reaction in the adhesive layer.

[0205] <Production of laminate> The above-mentioned adhesive layer 25 μm, UVA-TAC 32 μm, UVA-OCA 100 μm (ultraviolet barrier layer), and the oxygen barrier layer shown in Table 1 were arranged in this order on one surface in the thickness direction of Eagle Glass (thickness 0.55 mm, manufactured by Matsunami Glass Co., Ltd.), thereby producing a laminate.

[0206] Details of UVA-TAC and UVA-OCA are as follows: UVA-TAC: A film comprising KC2UA (TAC film, manufactured by Konica Minolta) and a hard coat layer in that order (obtained by hard coat treatment, forming a hard coat layer (thickness: 7 μm) on one side of KC2UA (thickness: 25 μm) (thickness: 32 μm) UVA-OCA: Adhesive tape with UV blocking layer and UV absorbing function, product name "CS9934U", thickness 100 μm, manufactured by Nitto Denko Corporation PET75μm: PET film, thickness 75μm, product name "G981 E75", manufactured by Mitsubishi Chemical Corporation

[0207] Example 2, Example 3, Example 4, Comparative Example 1 and Comparative Example 2 A laminate was produced in the same manner as in Example 1.

[0208] However, the type of oxygen barrier layer was changed according to Table 1.

[0209] The details of each oxygen barrier layer are as follows. PET25μm: PET film, thickness 25μm, product name "T602 E25", manufactured by Mitsubishi Chemical Corporation Acryl20μm: Acrylic film, thickness 20μm, product name "RV-20UB", manufactured by Toyo Kohan Co., Ltd. TAC28μm:TAC film, thickness 28μm, COP13μm: COP film, thickness 13μm, product name "ZF14-013", manufactured by Zeon Corporation PC70μm: PC film, thickness 70μm, product name "DURABIO" film made by Mitsubishi Chemical Corporation

[0210] Example 5 A laminate was produced in the same manner as in Example 4, except that the following component was used as the acid generator. Acid generator: Photoacid generator, sulfonium and C4F9HSO3 - Onium salt of 7 parts by mass (trade name: SP056, manufactured by ADEKA Corporation)

[0211] Example 6 A laminate was produced in the same manner as in Example 4, except that the following pressure-sensitive adhesive composition was used. <Preparation of adhesive composition> The following components were uniformly mixed per 100 parts by mass of the acrylic polymer (base polymer) into the above polymer solution containing the acrylic polymer of Production Example 2 to prepare a pressure-sensitive adhesive composition. Compound that develops color upon reaction with acid: leuco dye, 2'-anilino-6'-(N-ethyl-N-isopentylamino)-3'-methylspiro[phthalide-3,9'-[9H]xanthene] (trade name: S-205, manufactured by Yamada Chemical Industry Co., Ltd.) 2 parts by mass Acid generator: Photoacid generator (product name: CPI-310B, manufactured by San-Apro Co., Ltd.) 7 parts by mass Isocyanate crosslinking agent: (trade name "Takenate D110N", 75% ethyl acetate solution of xylylene diisocyanate trimethylolpropane adduct, manufactured by Mitsui Chemicals, Inc.) 0.25 parts by mass (solid content equivalent) Crosslinking catalyst: dibutyltin dilaurate (trade name "OL-1", 1 mass % ethyl acetate solution, manufactured by Tokyo Fine Chemical Co., Ltd.) 0.01 mass part (solid content equivalent) Crosslinking inhibitor (ligand for crosslinking catalyst): 3 parts by mass of acetylacetone

[0212] Example 7 A laminate was produced in the same manner as in Example 4, except that the following pressure-sensitive adhesive composition was used. <Preparation of adhesive composition> The following components were uniformly mixed per 100 parts by mass of the acrylic polymer (base polymer) into the above polymer solution containing the acrylic polymer of Production Example 2 to prepare a pressure-sensitive adhesive composition. Compound that develops color upon reaction with acid: leuco dye, 2'-anilino-6'-(N-ethyl-N-isopentylamino)-3'-methylspiro[phthalide-3,9'-[9H]xanthene] (trade name: S-205, manufactured by Yamada Chemical Industry Co., Ltd.) 2 parts by mass Acid generator: Photoacid generator (trade name: SP-056, manufactured by ADEKA Corporation) 7 parts by mass Isocyanate crosslinking agent: (trade name "Takenate D110N", 75% ethyl acetate solution of xylylene diisocyanate trimethylolpropane adduct, manufactured by Mitsui Chemicals, Inc.) 0.25 parts by mass (solid content equivalent) Crosslinking catalyst: dibutyltin dilaurate (trade name "OL-1", 1 mass % ethyl acetate solution, manufactured by Tokyo Fine Chemical Co., Ltd.) 0.01 mass part (solid content equivalent) Crosslinking inhibitor (ligand for crosslinking catalyst): 3 parts by mass of acetylacetone

[0213] <Evaluation> (oxygen permeability) The oxygen permeability of each oxygen barrier layer was measured at 23° C. and a relative humidity of 55% in accordance with JIS K7126-2 Appendix A. The results are shown in Table 1.

[0214] (Weather resistance test) For the laminates of each example and each comparative example, the samples were irradiated with ultraviolet light. Specifically, the adhesive sheet (adhesive layer) of the sample was irradiated with ultraviolet light from the Eagle Glass side through the glass in an environment of 23°C and relative humidity of 50% (the UV irradiation caused a reaction between the leuco dye and the photoacid generator in the adhesive layer). For this UV irradiation, a UV-LED lamp with a wavelength of 365 nm in a UV-LED irradiation device (model number "QEL-350-RU6W-CW-MY") manufactured by Quark Technology was used as the light source, and the cumulative irradiation light amount was 8000 mJ / cm. 2 (The cumulative amount of light irradiated in the wavelength range of 320 to 390 nm). In this manner, a colored laminate was produced. Next, the average transmittance, L * , a * , and , b * The values ​​were measured.

[0215] Next, the oxygen barrier layer side was irradiated for 24 hours with a super xenon lamp having an illuminance of 120 W in the wavelength range of 300 to 400 nm using a Super Xenon Weather Meter SX75 manufactured by Suga Test Instruments Co., Ltd. This gave a laminate after 24 hours of irradiation.

[0216] Next, the laminate and the average transmittance of the laminate after 24 hours of irradiation, L * , a * , and , b * The values ​​were measured.

[0217] Average transmittance, L * , a * , and , b * Specifically, each sample (laminate and laminate after 24 hours of irradiation) was placed in a transmittance measuring device (U4150 spectrophotometer, manufactured by Hitachi High-Tech Science Corporation) so that light was incident on the Eagle Glass side. Then, the average transmittance, L, at wavelengths of 400 nm to 700 nm was measured. * , a * , and , b * The values ​​of each were measured.

[0218] In detail, the average transmittance (T1) of the laminate in the wavelength range of 400 nm to 700 nm and the L * (L1 * ) and a for the laminate * (a1 * ) and b for the laminate * (b1 * ) and the average transmittance (T2) of the laminate at wavelengths of 400 nm to 700 nm after 24 hours of irradiation, and the L * (L2 * ) and a for the laminate after 24 hours of irradiation * (a2 * ) and b for the laminate after 24 hours of irradiation * (b2 * ) and were measured, respectively.

[0219] Then, the color difference (ΔE) was calculated based on the following formula (1). ΔE=((L2 * -L1 * ) 2 +(a 2 *-a 1 *) 2 +(b 2 *-b 1 *) 2 )1 / 2 (1) The results of T1, T2 and color difference (ΔE) are shown in Table 1.

[0220] [Table 1] [Explanation of symbols]

[0221] 1. Laminate 2 Adherent 3 Adhesive layer 4. Oxygen barrier layer 5. Active energy ray blocking layer 10 Discolored area 20 Base material 30 Middle Class 40 Surface protective layer S Color-changing adhesive sheet

Claims

1. The adhesive sheet comprises an adherend, a pressure-sensitive adhesive layer, and an oxygen barrier layer in this order in the thickness direction, the pressure-sensitive adhesive layer has a discolored portion that changes color in response to an external stimulus, The oxygen barrier layer has an oxygen permeability of 200 cm ３ / m ２ ・day・atm or less, the pressure-sensitive adhesive layer contains a pressure-sensitive adhesive composition, The adhesive composition comprises a leuco dye and a photoacid generator.

2. The laminate according to claim 1 , further comprising an active energy ray-blocking layer on one surface in the thickness direction of the oxygen barrier layer and / or on the other surface in the thickness direction of the oxygen barrier layer.

3. A method for producing a laminate comprising an adherend, an adhesive layer, and an oxygen barrier layer in that order in the thickness direction, the adhesive layer having a discolored portion that has changed color in response to an external stimulus, a first step of disposing the pressure-sensitive adhesive layer on one surface in the thickness direction of the adherend; a second step of forming the discolored portion in the pressure-sensitive adhesive layer by an external stimulus; and a third step of disposing the oxygen barrier layer on one surface of the pressure-sensitive adhesive layer in a thickness direction. The oxygen barrier layer has an oxygen permeability of 200 cm ３ / m ２ .times.day.atm or less.

4. a pressure-sensitive adhesive layer and an oxygen barrier layer in this order in the thickness direction, the adhesive layer is capable of changing color in response to an external stimulus; The oxygen barrier layer has an oxygen permeability of 200 cm ３ / m ２ ・day・atm or less, the pressure-sensitive adhesive layer contains a pressure-sensitive adhesive composition, The color-changeable adhesive sheet, wherein the adhesive composition contains a leuco dye and a photoacid generator.

5. The color-changeable pressure-sensitive adhesive sheet according to claim 4 , wherein the oxygen barrier layer is directly disposed on one surface of the pressure-sensitive adhesive layer in the thickness direction.

6. The color-changeable pressure-sensitive adhesive sheet according to claim 4 or 5, further comprising an active energy ray-blocking layer.

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