Active energy ray-curable adhesive composition, cured product, and laminate

Abstract

To provide an active energy ray-curable adhesive composition which gives a layer of a cured product having high strain recoverability and adhesive force and having high transparency at an initial stage and after exposure to a high-temperature and high-humidity environment.SOLUTION: The active energy ray-curable adhesive composition contains: a (meth)acrylic polyurethane (A) which is a reaction product of a polyol (a1), a polyisocyanate (a2), and a (meth)acrylic monomer (a3) having a hydroxy group or an isocyanate group; a mono(meth)acrylate (B) having no hydroxy group; a mono(meth)acrylate (C) having a hydroxy group; and a photopolymerization initiator (D). The content of the component (A) is 10-40 mass%, the content of the component (B) is 40-80 mass%, and the content of the component (C) is 5-30 mass% in terms of nonvolatile content mass when the total of the component (A), the component (B), and the component (C) is 100 mass%. The component (D) contains a photocleavage type polymerization initiator (D1) and a hydrogen abstraction type polymerization initiator (D2).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an active energy ray-curable pressure-sensitive adhesive composition, a cured product, and a laminate. [Background technology]

[0002] Adhesives are used to bond optical components together in the manufacturing process of mobile devices such as smartphones and tablets, digital home appliances such as digital cameras, audio equipment, and televisions, and communication devices such as radios and modems, for example, bonding touch sensors to front panels when manufacturing touch panels, or bonding touch sensors to image display devices, and these applications require high adhesive strength, transparency, and durability (maintaining high transparency even after storage under high temperature and humidity conditions).In addition, terminal devices have become increasingly flexible in recent years, and foldable and rollable devices have also been developed.

[0003] In the case of foldable devices, required properties include "bending resistance" that prevents peeling of the substrate or misalignment of the adhesive layer (cured layer) even when folded multiple times, and "strain recovery" that returns the device to a flat state after being bent and deformed. As such an adhesive, the present applicant has disclosed an active energy ray-curable adhesive composition containing specific amounts of polyurethane (meth)acrylate, alkyl mono(meth)acrylate, and primary hydroxyl group-containing mono(meth)acrylate. While this composition has excellent bending resistance, its strain recovery is still insufficient. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-070690 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an active energy ray-curable pressure-sensitive adhesive composition that provides a cured product layer that has high strain recovery, adhesive strength, and transparency both initially and after exposure to a high-temperature, high-humidity environment. [Means for solving the problem]

[0006] The present inventors have conducted extensive research and found that the above-mentioned problems can be solved. That is, the present invention relates to the following active energy ray-curable pressure-sensitive adhesive composition, cured product, and laminate.

[0007] 1. A (meth)acrylic polyurethane (A) which is a reaction product of a polyol (a1), a polyisocyanate (a2), and a (meth)acrylic monomer (a3) ​​having a hydroxy group or an isocyanate group; a mono(meth)acrylate (B) having no hydroxy group; a mono(meth)acrylate (C) having a hydroxy group; and a photopolymerization initiator (D), When the total of the components (A), (B), and (C) is taken as 100% by mass, the contents of the components (A), (B), and (C) are, in terms of nonvolatile mass, 10 to 40% by mass, 40 to 80% by mass, and 5 to 30% by mass, of the components (C); The active energy ray-curable pressure-sensitive adhesive composition, wherein the component (D) comprises a photocleavage polymerization initiator (D1) and a hydrogen abstraction polymerization initiator (D2).

[0008] 2. The active energy ray-curable pressure-sensitive adhesive composition according to item 1 above, wherein the ratio of the nonvolatile mass of the component (D1) to the component (D2) is (D1) / (D2)=0.1 to 10.

[0009] 3. The active energy ray-curable pressure-sensitive adhesive composition according to item 1 or 2 above, wherein the contents of the components (D1) and (D2) are each 0.1 to 2 mass% relative to 100 mass% of the total of the components (A), (B), and (C).

[0010] 4. The active energy ray-curable pressure-sensitive adhesive composition according to item 1 above, further comprising a tackifier resin (E).

[0011] 5. A cured product of the active energy ray-curable pressure-sensitive adhesive composition described in the preceding paragraph 1.

[0012] 6. A laminate having the cured product according to item 5 above on at least one surface of a substrate. [Effects of the Invention]

[0013] The active energy ray-curable pressure-sensitive adhesive composition according to the present invention (hereinafter simply referred to as "pressure-sensitive adhesive composition") provides a cured layer that has high strain recovery and adhesive strength, as well as high transparency initially and after exposure to a high-temperature, high-humidity environment. DETAILED DESCRIPTION OF THE INVENTION

[0014] The pressure-sensitive adhesive composition of the present invention contains a specific (meth)acrylic polyurethane (A) (hereinafter referred to as component (A)), a mono(meth)acrylate (B) (hereinafter referred to as component (B)) that does not have a hydroxy group, a mono(meth)acrylate (C) (hereinafter referred to as component (C)) that has a hydroxy group, and a photopolymerization initiator (D) (hereinafter referred to as component (D)). Note that (meth)acrylic means methacrylic or acrylic, and (meth)acrylate means acrylate or methacrylate.

[0015] The component (A) of the present invention is a reaction product of a polyol (a1) (hereinafter referred to as the component (a1)), a polyisocyanate (a2) (hereinafter referred to as the component (a2)), and a (meth)acrylic monomer (a3) ​​(hereinafter referred to as the component (a3)) having a hydroxy group or an isocyanate group, and is a component that enables the cured product layer to exhibit high adhesive strength and strain recovery.

[0016] The component (a1) refers to an alcohol having two or more hydroxy groups.

[0017] As the component (a1), a single-compound polyol or polymer polyol can be used, as well as a crystalline polyol or a non-crystalline polyol. Here, a crystalline polyol refers to a polyol that has a crystalline structure preferably at 20 to 60° C., more preferably at 20 to 40° C. These may be used alone or in combination of two or more.

[0018] Examples of single compound polyols include: aliphatic diols such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, 1,10-decanediol, butylethylpropanediol, and butylethylpentanediol; Alicyclic diols such as 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol; aliphatic triols such as trimethylolethane, trimethylolpropane, and glycerin; aliphatic polyols with 4 or more functional groups, such as pentaerythritol, ditrimethylolpropane, and dipentaerythritol; Dimer diols such as dimer diol and hydrogenated dimer diol; trimertriols such as trimertriol and hydrogenated trimertriol; Castor oils such as castor oil and castor oil-based modified polyols; Bisphenols such as bisphenol A and bisphenol F; sugar alcohols such as xylitol and sorbitol; Examples include derivatives of these polyols (for example, alkylene oxide adducts), etc. These may be used alone or in combination of two or more.

[0019] Examples of polymer polyols include polyether polyols, polyester polyols, poly(meth)acrylic polyols, polyolefin polyols, polycaprolactone polyols, polycarbonate polyols, etc. These may be used alone or in combination of two or more.

[0020] Among these, polymer polyols are preferred because they impart flexibility to the cured product layer and tend to exhibit high strain recovery. Specific polymer polyols are listed below.

[0021] Examples of polyether polyols include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, as well as (alkylene oxide-other alkylene oxide) copolymers containing multiple alkylene oxides as monomer components, such as ethylene oxide-propylene oxide copolymers. These may be used alone or in combination of two or more.

[0022] Commercially available polyether polyols include "ADEKA Polyether P-400," "ADEKA Polyether G-400," "ADEKA Polyether T-400," "ADEKA Polyether AM-302," "ADEKA Polyether P-1000," and "ADEKA Polyether P-2000" (all manufactured by ADEKA Corporation); "Polyethylene Glycol #1,540" (manufactured by Nacalai Tesque, Inc.); "Dipropylene Glycol" and "Polypropylene Glycol 400" (manufactured by Junsei Chemical Co., Ltd.); "PTMG650," "PTMG850," "PTMG1000," "PTMG1300," and "PTMG15 00, PTMG1800, PTMG2000, PTMG3000, PTMG3200, BioPTMG650, BioPTMG1000, BioPTMG2000, BioPTMG3000 (all manufactured by Mitsubishi Chemical Corporation), Preminol S3006, Preminol S3011, Preminol S4011, Preminol S4012, Preminol S4013, Preminol S4018, Preminol S4013F, Preminol S4318F (all manufactured by AGC Corporation), and the like.

[0023] Examples of polyester polyols include condensation polymers of polyols and polycarboxylic acids, ring-opening polymers of cyclic esters (lactones), and triple reaction products of polyols, polycarboxylic acids, and cyclic esters. These may be used alone or in combination of two or more.

[0024] Examples of polyols include those listed above as polyols as single compounds, which may be used alone or in combination of two or more.

[0025] Examples of polycarboxylic acids include: aliphatic dicarboxylic acids such as malonic acid, maleic acid, succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; Alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; Examples include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, trimellitic acid, etc. These may be used alone or in combination of two or more.

[0026] Examples of cyclic esters include propiolactone, β-methyl-δ-valerolactone, ε-caprolactone, etc. These may be used alone or in combination of two or more.

[0027] Commercially available polyester polyols include "Polylite RX-4800," "Polylite OD-X-2523," "Polylite OD-X-2547," "Polylite OD-X-2420," "Polylite OD-X-2692," and "Polylite OD-X-2108" (all manufactured by DIC Corporation); "Kuraray Polyol P-510," "Kuraray Polyol P-1010," "Kuraray Polyol P-2010," and "Kuraray Polyol F-510" (all manufactured by Kuraray Co., Ltd.).

[0028] Examples of polycarbonate polyols include reaction products of polyols and phosgene; ring-opening polymerization products of cyclic carbonates (such as alkylene carbonates); and the like. Examples of polyols include those mentioned above. Examples of alkylene carbonates include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, hexamethylene carbonate, and the like. These polyols and alkylene carbonates may be used alone or in combination of two or more.

[0029] Commercially available polycarbonate polyols include "Kuraray Polyol C-590" (manufactured by Kuraray Co., Ltd.); "Nippolan 4002," "Nippolan 4009," and "Nippolan 981" (all manufactured by Tosoh Corporation); and "Duranol T6002" and "Duranol T5652" (all manufactured by Asahi Kasei Corporation).

[0030] Examples of poly(meth)acrylic polyols include homopolymers or copolymers of acrylic monomers having one or more hydroxy groups, or copolymers of such copolymers with other monomers, which may be used alone or in combination of two or more.

[0031] Commercially available poly(meth)acrylic polyols include "ARUFON UH-2041" (manufactured by Toagosei Co., Ltd.); "Acrylic Polyol #6000" (manufactured by Taisei Fine Chemical Co., Ltd.); and "Acrylic Polyol PC #5984" (manufactured by Toei Kasei Co., Ltd.).

[0032] Examples of polyolefin polyols include polybutadiene having two or more hydroxy groups, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, chlorinated products thereof, etc. These may be used alone or in combination of two or more.

[0033] Commercially available polyolefin polyols include "NISSO-PB GI-1000," "NISSO-PB GI-2000," and "NISSO-PB GI-3000" (all manufactured by Nippon Soda Co., Ltd.).

[0034] Examples of polycaprolactone polyols include polycaprolactone diol, polycaprolactone triol, and polycaprolactone tetraol. These may be used alone or in combination of two or more. Commercially available products include "Polylite OD-X-2155" (manufactured by DIC Corporation); "Placcel 200," "Placcel 205," "Placcel 300," and "Placcel 400" (all manufactured by Daicel Corporation).

[0035] Among these polymer polyols, polyether polyols are preferred because they impart flexibility to the cured product layer and tend to exhibit high strain recovery.

[0036] The physical properties of the component (a1) include, for example, a number average molecular weight (a polystyrene equivalent value determined by gel permeation chromatography (GPC)) of preferably 700 to 30,000, more preferably 1,000 to 25,000, and even more preferably 1,500 to 20,000, in order to impart flexibility to the cured layer and facilitate the exhibiting of high strain recovery.

[0037] Examples of the component (a2) include aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; Aliphatic diisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; Examples thereof include alicyclic diisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated tolylene diisocyanate. Furthermore, as the component (a2), isocyanurates, adducts, or biurets of these may be used. These may be used alone or in combination of two or more. Among these, aliphatic diisocyanates and alicyclic diisocyanates are preferred, and hexamethylene diisocyanate and isophorone diisocyanate are more preferred.

[0038] The ratio of the (a1) component to the (a2) component is determined by the number of moles of the isocyanate group of the (a2) component (NCO (a2) ) and the number of moles of hydroxyl groups in the (a1) component (OH (a1) ) and the ratio (NCO (a2) / OH (a1) ) is preferably 1.01 to 2, more preferably 1.07 to 1.7.

[0039] The component (a3) ​​is a (meth)acrylic monomer (a3-1) having a hydroxy group (hereinafter referred to as the component (a3-1)) and a (meth)acrylic monomer (a3-2) having an isocyanate group (hereinafter referred to as the component (a3-2)). By using this component, the pressure-sensitive adhesive composition is easily cured, and the layer of the cured product is likely to exhibit high adhesive strength and strain recovery.

[0040] Examples of the component (a3-1) include: Mono(meth)acrylates having a hydroxy group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 7-hydroxyheptyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate; Di(meth)acrylates having a hydroxy group, such as trimethylolpropane di(meth)acrylate; Examples include N-(hydroxyalkyl)(meth)acrylamides such as N-(hydroxymethyl)(meth)acrylamide, N-(1-hydroxyethyl)(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, and N-(2-hydroxypropyl)(meth)acrylamide. These may be used alone or in combination of two or more.

[0041] Examples of the component (a3-2) include mono(meth)acrylates having an isocyanate group, such as 2-isocyanatoethyl(meth)acrylate and 2-(2-methacryloyloxyethyloxy)ethyl isocyanate; Examples include di(meth)acrylates having an isocyanate group such as 1,1-bis(acryloyloxymethyl)ethyl isocyanate, etc. These may be used alone or in combination of two or more.

[0042] Among these, mono(meth)acrylates having a hydroxy group, N-(hydroxyalkyl)(meth)acrylamides, and mono(meth)acrylates having an isocyanate group are preferred because they readily react with the functional groups (hydroxy groups derived from component (a1) or isocyanate groups derived from component (a2)) of the urethane prepolymer formed by the reaction of component (a1) with component (a2). 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, N-(1-hydroxyethyl)(meth)acrylamide, and 2-isocyanatoethyl (meth)acrylate are more preferred.

[0043] Component (A) is produced by various known methods. Hereinafter, component (a3) ​​will be described separately as component (A1) obtained using component (a3-1) (hereinafter referred to as component (A1)), and component (A2) obtained using component (a3-2) (hereinafter referred to as component (A2)).

[0044] The (A1) component can be obtained, for example, by reacting the (a1) component with the (a2) component to produce an isocyanate group-terminated urethane prepolymer (hereinafter referred to as the (A1') component), and then reacting the (A1') component with the (a3-1) component. The reaction conditions are typically a temperature of 70 to 85°C and a reaction time of 1 to 5 hours. The ratio of the (a1) component to the (a2) component to be used depends on the number of moles of isocyanate groups (NCO (a2) ) and the number of moles of hydroxyl groups in the (a1) component (OH (a1) ) and the ratio (NCO (a2) / OH (a1) ) is preferably 1.01 to 2. The ratio of the component (A1') to the component (a3-1) used is determined by the ratio of the number of moles of isocyanate groups (NCO (A1’) ) and the number of moles of hydroxyl groups in the latter (OH (a3-1) ) and the ratio (NCO (A1’) / OH (a3-1) ) is preferably 0.25 to 1.

[0045] Component (A2) can be prepared by reacting components (a1) and (a2) to obtain a hydroxyl-terminated urethane prepolymer (hereinafter referred to as component (A2')), and then reacting component (A2') with component (a3-2). The reaction temperature and reaction time are the same as for component (A1). The ratio of component (a1) to component (a2) used is (NCO (a2) / OH (a1) ) is preferably 0.50 to 0.99. The ratio of the component (A2') to the component (a3-2) used is determined by the ratio of the number of moles of isocyanate groups (NCO (a3-2) ) and the number of moles of hydroxyl groups in the former (OH (A2’) ) and the ratio (NCO (a3-2) / OH (A2’) ) is preferably 0.5 to 1.

[0046] The production of these components (A1) and (A2) may be carried out in the presence of an organic solvent, as described below, but is preferably carried out in the absence of a solvent to reduce environmental impact.Furthermore, the production of these components may also be carried out in the presence of component (B), as described below.

[0047] As for the physical properties of the obtained component (A), the weight-average molecular weight is preferably 30,000 to 250,000, more preferably 50,000 to 200,000, and even more preferably 80,000 to 150,000, from the viewpoints of facilitating application of the pressure-sensitive adhesive composition to the surface of the substrate and imparting flexibility to the cured layer formed, which tends to exhibit high strain recovery. The weight-average molecular weight is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

[0048] Furthermore, the average number of (meth)acryloyl groups per molecule of component (A) (hereinafter simply referred to as "average number of (meth)acryloyl groups") is preferably 1 to 4, as this provides flexibility to the cured product layer and makes it easier for high strain recovery to be exhibited. From the same perspective, the average number of (meth)acryloyl groups is preferably 1 to 3, and more preferably 1 to 2. Note that "(meth)acryloyl group" means an acryloyl group or a methacryloyl group.

[0049] The average number of (meth)acryloyl groups per molecule of component (A) refers to the average number of (meth)acryloyl groups present per molecule of component (A). For example, if 1 mole of ethylene glycol is reacted with 2 moles of diisocyanate as component (a2), and 2 moles of component (a3-1), if component (a3-1) is a mono(meth)acrylate, the average number of (meth)acryloyl groups will be 2, and if it is a tri(meth)acrylate, the average number of (meth)acryloyl groups will be 6.

[0050] The component (A) may contain two or more components with the same or different average numbers of (meth)acryloyl groups, or may be a mixture, and the average number of (meth)acryloyl groups in this case can be determined as a weighted average. For example, when 0.2 moles of component (A) with an average number of (meth)acryloyl groups of 1 and 0.8 moles of component (A) with an average number of (meth)acryloyl groups of 2 are contained, the composition is as follows: (Formula 2) [Average number of (meth)acryloyl groups per molecule of component (A)] =(1×0.2+2×0.8) / (0.2+0.8)=1.8

[0051] When the total of components (A), (B), and (C) is taken as 100% by mass, the content of component (A) is 10 to 40% by mass in terms of nonvolatile mass (the same applies hereinafter). If the content of component (A) is less than 10% by mass, the strain in the cured layer becomes difficult to recover (resulting in poor strain recovery). If the content of component (A) is more than 40% by mass, the storage modulus of the pressure-sensitive adhesive composition becomes too high, which tends to result in poor conformability and adhesion between the substrate and the pressure-sensitive adhesive composition, and also tends to result in poor transparency of the cured layer. From the same viewpoint, the content of component (A) is preferably 15 to 35% by mass, more preferably 20 to 30% by mass.

[0052] Component (B) is a mono(meth)acrylate that does not have a hydroxy group, and is a component that imparts flexibility to the layer of the cured product, making it easier for the layer to exhibit high strain recovery.

[0053] Examples of component (B) include: Methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate aliphatic mono(meth)acrylates such as n-decyl (meth)acrylate, tri-n-decyl (meth)acrylate, n-dodecyl (meth)acrylate (lauryl (meth)acrylate), n-tetradecyl (meth)acrylate (myristyl (meth)acrylate), n-hexadecyl (meth)acrylate (palmityl (meth)acrylate), n-octadecyl (meth)acrylate (stearyl (meth)acrylate), isostearyl (meth)acrylate, and carbitol (meth)acrylate; alicyclic mono(meth)acrylates such as cyclohexyl (meth)acrylate, norbornyl (meth)acrylate, isobornyl (meth)acrylate, norbornanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, and tricyclodecanedimethylol di(meth)acrylate; Examples of the aromatic mono(meth)acrylate include phenyl (meth)acrylate, benzyl acrylate, 2-phenylethyl (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, m-phenylphenoxyethyl (meth)acrylate, p-phenylphenoxyethyl (meth)acrylate, o-phenoxybenzyl (meth)acrylate, m-phenoxybenzyl (meth)acrylate, p-phenoxybenzyl (meth)acrylate, ethoxylated-o-phenylphenol (meth)acrylate, ethoxylated-m-phenylphenol (meth)acrylate, ethoxylated-p-phenylphenol (meth)acrylate, ethylene oxide-modified-o-cumylphenol (meth)acrylate, ethylene oxide-modified-m-cumylphenol (meth)acrylate, ethylene oxide-modified-p-cumylphenol (meth)acrylate, and triphenylmethyl (meth)acrylate. These may be used alone or in combination of two or more. Among them, aliphatic mono(meth)acrylates are preferred, and n-octyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, lauryl(meth)acrylate, and carbitol(meth)acrylate are more preferred, since the cured product layer has a high storage modulus and is likely to exhibit strain recovery.

[0054] When the total of components (A), (B), and (C) is taken as 100% by mass, the content of component (B) is 40 to 80% by mass. If the content of component (B) is less than 40% by mass, the storage modulus of the pressure-sensitive adhesive composition becomes too high, which tends to result in poor conformability and adhesion between the substrate and the pressure-sensitive adhesive composition, and also tends to reduce the transparency of the cured layer. If the content of component (B) exceeds 80% by mass, the adhesive strength of the cured layer tends to deteriorate. From the same viewpoint, the content of component (B) is preferably 50 to 75% by mass, more preferably 60 to 70% by mass.

[0055] Component (C) is a mono(meth)acrylate having a hydroxy group, and is a component that allows the layer of the cured product to exhibit high transparency after exposure to high temperature and high humidity.

[0056] Examples of the component (C) include aliphatic mono(meth)acrylates having one primary hydroxy group, such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 5-hydroxypentyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate, 7-hydroxyheptyl(meth)acrylate, and 8-hydroxyoctyl(meth)acrylate; aliphatic mono(meth)acrylates having one secondary hydroxy group, such as 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, 4-hydroxyhexyl(meth)acrylate, and 5-hydroxyhexyl(meth)acrylate; aliphatic mono(meth)acrylates having two hydroxy groups, such as 2,3-dihydroxypropyl (meth)acrylate, 3,4-dihydroxybutyl (meth)acrylate, glycerin mono(meth)acrylate, and 1,4-dihydroxyheptyl (meth)acrylate; alicyclic mono(meth)acrylates having one hydroxy group, such as 4-hydroxycyclohexyl(meth)acrylate and 3-hydroxy-1-adamantyl(meth)acrylate; Alicyclic mono(meth)acrylates having two hydroxy groups, such as 1,4-cyclohexanedimethanol mono(meth)acrylate and 3,5-dihydroxyadamantyl (meth)acrylate; Examples include aromatic (meth)acrylates having one hydroxy group such as 2-hydroxy-3-phenoxypropyl (meth)acrylate, which may be used alone or in combination of two or more.

[0057] Among these, (meth)acrylates having one primary hydroxy group are preferred, and 2-hydroxypropyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are more preferred, since the cured layer tends to exhibit high transparency after exposure to high temperature and high humidity.

[0058] The content of component (C) is 5 to 30% by mass when the total of components (A), (B), and (C) is taken as 100% by mass. If the content of component (C) is less than 5% by mass, the adhesive composition is likely to whiten in high-temperature, high-humidity environments. If the content of component (C) is more than 30% by mass, the storage modulus of the adhesive composition becomes too high, which tends to result in poor conformability and adhesion between the substrate and the adhesive composition, and also tends to reduce the transparency of the cured product layer. From the same perspective, the content of component (C) is preferably 10 to 25% by mass, more preferably 15 to 20% by mass.

[0059] Component (D) is a photopolymerization initiator, and in the present invention, it contains a photocleavage polymerization initiator (D1) (hereinafter referred to as component (D1)) and a hydrogen abstraction polymerization initiator (D2) (hereinafter referred to as component (D2)). The combined use of components (D1) and (D2) provides the effect of achieving both high adhesive strength and strain recovery in the cured product layer.

[0060] The component (D1) is a polymerization initiator that undergoes bond cleavage when exposed to light, generating radicals. Examples of the component (D1) include: hydroxyketones such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one), 2-hydroxy-1-[4-{4-(2-hydroxy-2-methylpropionyl)benzyl}phenyl]-2-methylpropan-1-one, and 2-isopropoxy-2-phenylacetophenone; acylphosphine oxides such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Benzil ketals such as 2,2-dimethoxy-2-phenylacetophenone (2,2-dimethoxy-1,2-diphenylethan-1-one); Oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)-2-(o-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetyloxime); Examples include amino ketones such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropiophenone, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, and 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)butan-1-one. These may be used alone or in combination of two or more.

[0061] Commercially available products of component (D1) include, for example, "Omnirad184", "Omnirad1173", "Omnirad651", "Omnirad2959", "Omnirad127", "Omnirad907", "Omnirad369", "Omnirad369E", "Omnirad379EG", "Omnirad819", "Omnirad TPO H", "Irgacure OXE01", "Irgacure OXE2", "Irgacure OXE3", and "Irgacure OXE4" (all manufactured by IGM Resins), and "LUNACURE200" (manufactured by DKSH Japan).

[0062] Among these, hydroxyketones and acylphosphine oxides are preferred because the cured layer is likely to exhibit high adhesive strength, and 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are more preferred.

[0063] The content of the (D1) component relative to the total of 100% by mass of the (A), (B), and (C) components is preferably 0.1 to 2% by mass, more preferably 0.25 to 2% by mass, and even more preferably 0.5 to 2% by mass, since the cured product layer is likely to exhibit high adhesive strength.

[0064] Component (D2) is a photopolymerization initiator that generates radicals by abstracting hydrogen atoms from nearby molecules. Examples of the component (D2) include: benzophenones such as benzophenone, 4-methylbenzophenone, benzophenone 2-carboxylate methyl (methyl 2-benzoylbenzoate), and 4,4-bis(dimethylamino)benzophenone; thioxanthones such as 2,4-diethylthioxanthone and 2-isopropylthioxanthone; Examples include oxyacetic acid esters such as oxyphenylacetic acid 2-(2-oxo-2-phenylacetoxyethoxy)ethyl ester and oxyphenylacetic acid 2-(2-hydroxyethoxy)ethyl ester; methyl benzoyl formate (methyl oxophenylacetate, 1-methoxy-2-phenyl-1,2-ethanedione, phenylglyoxylic acid methyl ester), etc. These may be used alone or in combination of two or more.

[0065] Commercially available products of component (D2) include, for example, "Omnirad BP Flakes," "Omnirad754," "Omnirad MBF," "Omnirad DETX," and "Omnirad ITX" (all manufactured by IGM Resins), "KAYACURE DETX-S," and "LUNACURE 2-ITX" (all manufactured by Nippon Kayaku Co., Ltd.), "Lunacure BP," "Lunacure 81," and "Lunacure 251" (manufactured by DKSH Japan), and the like.

[0066] Among these, benzophenones, oxyacetic acid esters, and methylbenzoyl formate are preferred because the cured product layer is likely to exhibit high strain recovery properties, 4-methylbenzophenone, oxyphenylacetic acid 2-(2-oxo-2-phenylacetoxyethoxy)ethyl ester, oxyphenylacetic acid 2-(2-hydroxyethoxy)ethyl ester, and methylbenzoyl formate are more preferred, and 4-methylbenzophenone and methylbenzoyl formate are even more preferred.

[0067] The content of the (D2) component relative to the total of 100% by mass of the (A), (B), and (C) components is preferably 0.1 to 2% by mass, more preferably 0.2 to 2% by mass, and even more preferably 0.25 to 2% by mass, since the cured product layer is likely to exhibit high strain recovery.

[0068] The ratio of the nonvolatile mass of the (D1) component to the (D2) component is preferably (D1) / (D2)=0.1 to 10, more preferably 0.125 to 8, and even more preferably 0.25 to 4, because this makes it easier for the cured product layer to achieve both high adhesive strength and strain recovery.

[0069] The pressure-sensitive adhesive composition of the present invention may also contain a photopolymerization initiator (D3) (hereinafter referred to as component (D3)) other than the components (D1) and (D2).

[0070] Examples of the (D3) component include bis(η 5 -2,4-cyclopentadien-1-yl)-bis{2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl}titanium, 4-isobutylphenyl(4-methylphenyl)iodonium hexafluorophosphate, sulfonium hexafluorophosphate, sulfonium tetrakis(pentafluorophenyl)borate, etc. These may be used alone or in combination of two or more.

[0071] Commercially available products of component (D3) include "Omnirad784", "Omnicat250", "Omnicat270", and "Irgacure290" (all manufactured by IGM Resins).

[0072] The content of the component (D3) relative to the total of the components (A), (B), and (C) (100% by mass) is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

[0073] The pressure-sensitive adhesive composition of the present invention may further contain a tackifier resin (E) (hereinafter referred to as component (E)).

[0074] Examples of component (E) include rosin resins, aliphatic petroleum resins, aromatic petroleum resins, phenolic resins, styrene resins, xylene resins, coumarone-indene resins, terpene resins, terpene phenolic resins, aromatic modified terpene resins, and hydrogenated versions of these resins. These may be used alone or in combination of two or more.

[0075] Examples of commercially available products of component (E) include "Pensel D-135," "Super Ester A-125," "Pine Crystal KE-100," "Pine Crystal KE-311," "Pine Crystal KE-604," "Alcon P-100," "Alcon M-100," "Alcon M-135," and "Alcon P-140" (manufactured by Arakawa Chemical Industries, Ltd.), "YS Polystar K125," "YS Polystar N125," "YS Polystar TH130," "YS Polystar G150," and "YS Polystar T-160" (all manufactured by Yasuhara Chemical Co., Ltd.), and "FTR0100," "FTR0120," "FTR2085," "FTR2120," "FTR2140," "FTR6100," "FTR6110," and "FTR6125" (all manufactured by Mitsui Chemicals, Inc.).

[0076] The content of the (E) component relative to the total of the (A), (B), and (C) components (100% by mass) is preferably 10% by mass or less, and more preferably 5% by mass or less, since the cured product layer is likely to exhibit high adhesive strength.

[0077] The pressure-sensitive adhesive composition of the present invention may further contain a polyfunctional monomer. Examples of polyfunctional monomers include (meth)acrylates such as hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and urethane (meth)acrylate. These may be used alone or in combination of two or more.

[0078] The content of the polyfunctional monomer relative to the total of the components (A), (B) and (C) (100% by mass) is preferably 10% by mass or less, and more preferably 5% by mass or less.

[0079] The pressure-sensitive adhesive composition of the present invention may further contain additives, such as surface conditioners, surfactants, UV absorbers, antioxidants, light stabilizers, inorganic fillers, silane coupling agents, colloidal silica, antifoaming agents, wetting agents, and rust inhibitors, which may be used alone or in combination of two or more.

[0080] The pressure-sensitive adhesive composition of the present invention can be obtained by mixing components (A), (B), (C), and (D), and optionally, component (E), the polyfunctional monomer, and additives. The mixing method and order can be freely selected. Furthermore, when component (A) is diluted with component (B), a solution of component (A) and component (B) can be mixed with components (C) and (D), and optionally, component (E), the polyfunctional monomer, and additives.

[0081] The pressure-sensitive adhesive composition of the present invention is substantially solvent-free, and when it contains an organic solvent, the content thereof is preferably less than 1% by mass, more preferably less than 0.1% by mass.

[0082] Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, ethylbenzene, n-propylbenzene, t-butylbenzene, o-xylene, m-xylene, p-xylene, tetralin, decalin, and aromatic naphtha; aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane, isooctane, and n-decane; alicyclic hydrocarbons such as cyclohexane; esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, 2-hydroxyethyl acetate, 2-butoxyethyl acetate, 3-methoxybutyl acetate, and methyl benzoate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, and methylcyclohexanone; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether; and alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, s-butanol, and t-butanol.

[0083] The cured product of the present invention is obtained by curing the pressure-sensitive adhesive composition.

[0084] The cured product of the present invention can be obtained by applying the pressure-sensitive adhesive composition to a substrate and then irradiating the substrate with active energy rays. Alternatively, the composition may be dried under heating before being irradiated with active energy rays.

[0085] Examples of the substrate include plastic and paper.

[0086] Examples of plastics include olefin resins such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, and cycloolefin; Polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene terephthalate (PBT), polybutylene adipate terephthalate (PBAT), polylactic acid, polyhydroxyalkanoic acid, and polycaprolactone; (Meth)acrylic resins such as polymethyl (meth)acrylate; vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, and poly(ethylene-vinyl acetate); styrene resins such as polystyrene, poly(styrene-acrylonitrile) (AS resin), and poly(styrene-butadiene-acrylonitrile) (ABS resin); Examples of the resin include polycarbonate, polyether ether ketone, polyamide, polyimide, epoxy resin, melamine resin, diacetyl cellulose, triacetyl cellulose, and fluororesin.

[0087] Examples of paper include bleached kraft paper, unbleached kraft paper, fine paper, medium-quality paper, lightly coated paper, coated paper, processed base paper, paperboard, white paperboard, liner, semi-glassine paper, glassine paper, parchment paper, and top-coated paper.

[0088] Other substrates that can be used include, for example, fabrics such as woven fabrics and nonwoven fabrics; foam sheets such as foamed polyurethane and foamed polychloroprene rubber; rubbers such as natural rubber and butyl rubber; metals such as aluminum and copper; glass, ITO, and the like.

[0089] Furthermore, as the substrate, these crosslinked films or laminated films may be used, and any of untreated films, films that have been subjected to light to heavy release treatment, and films that have an easy-adhesion layer or anchor layer may be used.

[0090] Examples of the coating method include an applicator, a bar coater, a Mayer bar coater, a roll coater, a die coater, a comma coater, a knife coater, a gravure coater, a reverse gravure coater, offset printing, flexographic printing, screen printing, etc. The amount of the active energy ray-curable pressure-sensitive adhesive composition to be applied is such that the film thickness of the cured product is preferably 10 to 100 μm, more preferably 20 to 60 μm.

[0091] Examples of active energy rays include light rays such as ultraviolet rays, infrared rays, and visible light rays, as well as electron beams, X-rays, α rays, β rays, γ rays, and neutron rays. In the present invention, light rays are preferred, and ultraviolet rays are more preferred.

[0092] Examples of ultraviolet light sources include xenon lamps, high-pressure mercury lamps, metal halide lamps, UV-LEDs, etc. The irradiation intensity of ultraviolet light is usually 80 to 160 mW / cm. 2 The cumulative light intensity is usually 100 to 3000 mJ / cm 2 The conveying speed is usually 5 to 50 m / min.

[0093] The laminate of the present invention has the cured product on at least one surface of a substrate. The substrate, coating method, irradiation conditions, etc. used are the same as those described above. [Example]

[0094] The present invention will be specifically described below through examples and comparative examples. However, the technical scope of the present invention is not limited thereto. In the examples, "parts" and "%" are by mass unless otherwise specified.

[0095] Manufacturing Example 1 A reactor equipped with a condenser, a stirrer, and a nitrogen inlet tube was charged with 88.4 parts of polypropylene glycol (trade name: "ADEKA Polyether P-2000", number average molecular weight: 2000, manufactured by ADEKA Corporation), 10.6 parts of isophorone diisocyanate (hereinafter referred to as "IPDI"), 0.1 parts of methoquinone (hereinafter referred to as "MQ"), and 0.1 parts of stannous octoate. The temperature was raised to 70°C and maintained for 3 hours. After that, 1.0 parts of 4-hydroxybutyl acrylate (hereinafter referred to as "4HBA") was added and maintained at 70°C for 2 hours. The NCO value was measured to confirm completion of the reaction, yielding acrylic polyurethane (A-1). The NCO value was measured in accordance with JIS K 1603-1 (the same applies below).

[0096] Manufacturing Example 2 To a reaction apparatus similar to that used in Production Example 1, 97.1 parts of polypropylene glycol (trade name: "Preminol S4318F", number average molecular weight: 18,000, manufactured by AGC Corporation) (hereinafter referred to as "S4318F"), 2.0 parts of IPDI, 0.1 parts of MQ, and 0.1 parts of stannous octoate were added, the temperature was raised to 70°C, and the mixture was maintained at that temperature for 3 hours. After that, 1.0 part of 4HBA was added, the mixture was maintained at 70°C for 2 hours, and the NCO value was measured to confirm completion of the reaction, thereby obtaining an acrylic polyurethane (A-2).

[0097] Manufacturing Example 3 A reaction apparatus similar to that used in Production Example 1 was charged with 98.5 parts of S4318F, 0.6 parts of IPDI, 0.1 parts of MQ, and 0.1 parts of stannous octoate, and the mixture was heated to 70°C and maintained at that temperature for 3 hours. Thereafter, 0.9 parts of 2-isocyanatoethyl methacrylate (trade name: Karenz MOI, manufactured by Showa Denko K.K.) was added, and the mixture was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining a methacrylic polyurethane (A-3).

[0098] Manufacturing Example 4 To a reaction apparatus similar to that used in Production Example 1, 98.0 parts of S4318F, 1.4 parts of hexamethylene diisocyanate, 0.1 parts of MQ, and 0.1 parts of stannous octoate were added, and the mixture was heated to 70°C and maintained at that temperature for 3 hours. After that, 0.6 parts of N-hydroxymethylacrylamide was added, and the mixture was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining an acrylic polyurethane (A-4).

[0099] Example 1 An active energy ray-curable pressure-sensitive adhesive composition was obtained by mixing acrylic polyurethane (A-1), 2-ethylhexyl acrylate as the component (B), 4-hydroxybutyl acrylate as the component (C), 1-hydroxycyclohexyl phenyl ketone (trade name: "Omnirad184", manufactured by IGM Resins) as the component (D1), and methyl benzoyl formate (trade name: "Omnirad MBF", manufactured by IGM Resins) as the component (D2) in the blending ratios shown in Table 1.

[0100] Examples 2 to 20, Comparative Examples 1 to 9 The same procedure as in Example 1 was carried out except that the compositions and contents were changed as shown in Table 1, to obtain active energy ray-curable pressure-sensitive adhesive compositions.

[0101] <Creating a layer of cured material> The pressure-sensitive adhesive composition of each Example and Comparative Example was applied to a 75 μm thick polyester film treated with a heavy release agent (product name: "PET75x1-J4", manufactured by Nippa Corporation) so that the film thickness after curing would be 50 μm, and the release-treated surface of a 75 μm thick polyester film treated with a light release agent (product name: "PET75x1-J0L", manufactured by Nippa Corporation) was bonded to the applied layer. Next, in the atmosphere, a high-pressure mercury lamp (80 mW / cm 2 , 1300mJ / cm 2 ) to prepare a pre-laminate (light release treated polyester film / cured product layer / heavy release treated polyester film). Note that for the pressure-sensitive adhesive composition of Example 4, the irradiation conditions were 1300 mJ / cm 2 to 2600mJ / cm 2 I changed it to. A test piece of 1 cm x 1 cm was cut from the pre-laminate, and then the light release treated polyester film and the heavy release treated polyester film were peeled off to obtain a layer of the cured product.

[0102] <Storage modulus> Twenty layers of the cured product were stacked to form a 1 mm thick pressure-sensitive adhesive sheet, and the dynamic viscoelasticity was measured under the following conditions using a commercially available measuring device (trade name: "MCR302", manufactured by Anton Paar). From the measurement results, the storage modulus G' (unit: kPa) at -20°C and 25°C was calculated.

[0103] (Measurement conditions) Deformation mode: Torsion Measurement frequency: 1Hz Distortion: 0.01~1% AUTO setting Heating rate: 3°C / min Measurement temperature: -80~100℃ Shape: Parallel plate 8.0mmφ

[0104] <Distortion recovery> Twenty layers of the cured product were stacked to form a 1 mm thick adhesive sheet, and a commercially available measuring instrument (trade name: "MCR302e", manufactured by Anton Paar) was used to apply a pressure of 20 kPa to the adhesive sheet layer at a temperature of 25°C for 10 minutes (deformation mode: torsion, shape: parallel plate 8.0 mmφ), and the maximum strain amount (unit: %) of the adhesive sheet was read. Next, the pressure was removed and the adhesive sheet was allowed to stand for 10 minutes, and the strain amount (unit: %) of the adhesive sheet was read. Each strain amount was substituted into Equation 1 to determine the strain recovery. A larger value indicates better strain recovery.

[0105] (Equation 1) Strain recovery (%) = {(BA) / A} × 100 (A: Maximum distortion after applying pressure for 10 minutes, B: Distortion after removing pressure and leaving it for 10 minutes)

[0106] <Preparation of laminate> The light release treated polyester film was peeled off from the pre-laminate obtained in the same manner as in the previous paragraph, and in its place a 50 μm thick polyester film (product name: "Cosmoshine A-4300", manufactured by Toyobo Co., Ltd.) was attached with a 2 kg roller and left for 2 hours. Next, a 2.5 cm × 8 cm test piece was cut from this, and the heavy release treated polyester film was peeled off to obtain a single-sided PSA sheet (Cosmoshine A-4300 / cured product). The mixture was attached to a glass plate with a 2 kg roller and left to stand for 24 hours under conditions of a temperature of 25°C and a humidity of 50% to produce a laminate (Cosmoshine A-4300 / cured product layer / glass).

[0107] <Adhesive strength> The adhesive strength (N / 25 mm) of the cured product was measured by peeling the glass plate from the laminate in a 180° direction at a rate of 300 mm / min using a commercially available testing machine (Tensilon universal material testing machine, manufactured by A&D Co., Ltd.). An adhesive strength of 4.0 N / 25 mm or more indicates good adhesive strength, and the larger the value, the better the adhesive strength.

[0108] <Transparency> The light release treated polyester film was peeled off from the pre-laminate and attached to a glass plate with a rubber roller to produce a laminate (heavy release treated polyester film / cured product layer / glass). Next, the heavy release treated polyester film was peeled off, and the color difference (b * ) was measured. A color difference of less than 0.30 indicates good transparency, and the smaller the value, the better the transparency. The obtained color difference value includes the value of the substrate (glass plate).

[0109] <Moisture and heat resistance> The light-release treated polyester film was peeled off from the pre-laminate, and a 50 μm-thick polyester film (trade name: "Lumirror 50T60", manufactured by Toray Industries, Inc.) was instead bonded with a rubber roller. After leaving for 2 hours, an 8 cm x 8 cm test piece was cut out, and the heavy-release treated polyester film was peeled off to obtain a single-sided PSA sheet (Lumirror 50T60 / cured product). The laminate was then bonded to a glass plate with a rubber roller and subjected to a heat press (pressure: 0.5 MPa, temperature: 40°C) for 30 minutes to produce a laminate (Lumirror 50T60 / cured product layer / glass). The initial color difference (b * Thereafter, the laminate was placed in a thermo-hygrostat at a temperature of 85°C and a humidity of 85%, and the color difference after 36 hours was measured in the same manner. The change in color from the initial value (Δb * The change range (△b * ) is less than 0.15, the moist heat resistance is good, and the smaller the value, the better. Note that all obtained color difference values ​​include the value of the substrate (Lumirror 50T60, glass plate).

[0110] [Table 1] *1: Expressed as a ratio when the total of components (A), (B), and (C) is 100% by mass. *2: Shown as a ratio to 100% by mass of the total of components (A), (B), and (C).

[0111] The symbols in Table 1 represent the following compounds: <Acrylic polyurethane> A-1: Acrylic polyurethane of Manufacturing Example 1 A-2: Acrylic polyurethane of Manufacturing Example 2 A-3: Methacrylic polyurethane of Production Example 3 A-4: Acrylic polyurethane of Manufacturing Example 4 <Mono(meth)acrylate> B-1: 2-Ethylhexyl acrylate B-2: n-octyl acrylate B-3: Lauryl acrylate B-4: Carbitol acrylate C-1: 4-hydroxybutyl acrylate C-2: 2-hydroxypropyl acrylate <Photopolymerization initiator> D1-1: 1-Hydroxycyclohexylphenyl ketone (trade name: "Omnirad184", manufactured by IGM Resins) D1-2: Trimethylbenzoyldiphenylphosphine oxide (trade name: "Omnirad TPO H", manufactured by IGM Resins) D1-3: 2-hydroxy-2-methyl-1-phenylpropan-1-one (trade name: "Omnirad1173", manufactured by IGM Resins) D2-1: Methyl benzoyl formate (trade name: "Omnirad MBF", manufactured by IGM Resins) D2-2: A mixture of 2-(2-oxo-2-phenylacetoxyethoxy)ethyl oxyphenylacetic acid and 2-(2-hydroxyethoxy)ethyl oxyphenylacetic acid (trade name: "Omnirad754", manufactured by IGM Resins) D2-3: 4-Methylbenzophenone <Tackifying resin> E-1: Terpene phenol resin (product name: "YS Polystar K125", manufactured by Yasuhara Chemical Co., Ltd.)

Claims

1. a (meth)acrylic polyurethane (A) which is a reaction product of a polyol (a1), a polyisocyanate (a2), and a (meth)acrylic monomer (a3) ​​having a hydroxy group or an isocyanate group; a mono(meth)acrylate (B) having no hydroxy group; a mono(meth)acrylate (C) having a hydroxy group; and a photopolymerization initiator (D), When the total of the components (A), (B), and (C) is taken as 100% by mass, the contents of the components (A), (B), and (C) are, in terms of nonvolatile mass, 10 to 40% by mass, 40 to 80% by mass, and 5 to 30% by mass, of the components (C); The active energy ray-curable pressure-sensitive adhesive composition, wherein the component (D) comprises a photocleavage polymerization initiator (D1) and a hydrogen abstraction polymerization initiator (D2).

2. 2. The active energy ray-curable pressure-sensitive adhesive composition according to claim 1, wherein the ratio of the nonvolatile mass of the component (D1) to the component (D2) is (D1) / (D2)=0.1 to 10.

3. 3. The active energy ray-curable pressure-sensitive adhesive composition according to claim 1, wherein the contents of the components (D1) and (D2) are each 0.1 to 2 mass% relative to 100 mass% of the total of the components (A), (B), and (C).

4. The active energy ray-curable pressure-sensitive adhesive composition according to claim 1 , further comprising a tackifier resin (E).

5. A cured product of the active energy ray-curable pressure-sensitive adhesive composition according to claim 1.

6. A laminate having the cured product according to claim 5 on at least one surface of a substrate.

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