Curable adhesive composition

Abstract

The present invention provides an adhesive composition capable of forming an adhesive layer that exhibits high adhesion to the adherend after curing. [Solution] The curable adhesive composition of the present invention comprises an adhesive polymer, a polyfunctional cyclic ether compound having two or more cyclic ether groups in one molecule, and an acid generator. The content of the polyfunctional cyclic ether compound is 10 to 100 parts by mass per 100 parts by mass of the total amount of the adhesive polymer. The adhesive polymer preferably includes an acrylic polymer. The acrylic polymer preferably contains 0.5 to 10% by mass of constituent units derived from carboxyl group-containing monomers.

Description

[Technical Field]

[0001] This invention relates to a curable adhesive composition. [Background technology]

[0002] Adhesive sheets used in image display devices and portable electronic devices such as mobile phones, smartphones, digital cameras, liquid crystal displays (LCDs), and organic EL displays require various performance characteristics, including high adhesive strength.

[0003] In recent years, organic EL panels using flexible substrates such as resin films have been put into practical use, and flexible displays that can be folded have been proposed. In flexible displays, in addition to the display panel such as the organic EL panel being foldable, the constituent components are also foldable, and these components are bonded together via an adhesive sheet. In foldable displays, bending is repeated in the same place. At the bending point, compressive stress is applied to the inside and tensile stress to the outside, causing distortion at and around the bending point, which raises concerns that creases or marks may appear at the bending point, or that the adhesive layer may peel off.

[0004] Incidentally, there is a known adhesive sheet that has a curable adhesive layer that exhibits adhesion to a substrate by bonding the adhesive layer to the substrate, allowing it to adhere tightly, and then curing it (see, for example, Patent Document 1). Such an adhesive sheet can achieve high adhesion to a substrate. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2015-54942 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, the curable adhesive layer may undergo curing shrinkage. As a result of the curing shrinkage, the contact area between the adherend and the adhesive layer may decrease, and the adhesive layer may be likely to peel off from the adherend. In particular, when the adhesive layer is used in an area that undergoes repeated bending, or when the adherend has an uneven surface shape, it tends to peel off more easily.

[0007] The present invention has been conceived under such circumstances, and an object thereof is to provide an adhesive composition capable of forming an adhesive layer having high adhesiveness to an adherend after curing.

Means for Solving the Problems

[0008] As a result of intensive studies to achieve the above object, the present inventors have found that, according to a specific adhesive composition, it is possible to form an adhesive layer having high adhesiveness to an adherend after curing. The present invention has been completed based on these findings.

[0009] That is, the present invention includes a tacky polymer, a polyfunctional cyclic ether compound having two or more cyclic ether groups in one molecule, and an acid generator, and provides a curable adhesive composition in which the content of the polyfunctional cyclic ether compound is 10 to 100 parts by mass with respect to 100 parts by mass of the total amount of the tacky polymer.

[0010] The tacky polymer preferably includes an acrylic polymer.

[0011] The acrylic polymer preferably contains 0.5 to 10% by mass of structural units derived from a carboxy group-containing monomer and / or an acid anhydride monomer.

[0012] The cyclic ether group in the polyfunctional cyclic ether compound preferably includes an epoxy group and / or an oxetanyl group.

[0013] It is preferable that the acid generator contains a photoacid generator whose cation part is aromatic sulfonium.

[0014] The curable adhesive composition is preferably used for fixing members to each other in electric and electronic devices.

[0015] The present invention also provides a curable adhesive sheet including an adhesive layer composed of the curable adhesive composition.

[0016] The present invention also provides an electric and electronic device including an adhesive sheet obtained by curing the curable adhesive sheet, wherein the adhesive sheet fixes members to each other on both adhesive surfaces.

Effects of the Invention

[0017] According to the curable adhesive composition of the present invention, an adhesive layer having high adhesiveness to an adherent can be formed after curing.

Brief Description of the Drawings

[0018] [Figure 1] It is a cross-sectional view of an adhesive sheet according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0019] [Curable Adhesive Composition] The curable adhesive composition according to an embodiment of the present invention at least includes a tacky polymer, a polyfunctional cyclic ether compound, and an acid generator.

[0020] The above curable adhesive composition is an adhesive composition in which the formed adhesive layer is curable. The above curable adhesive composition contains the above polyfunctional cyclic ether compound as a curable compound. The above polyfunctional cyclic ether compound undergoes cationic curing by the action of the above acid generator, and the adhesive layer hardens. Such cationic curing results in less curing shrinkage compared to conventional radical curing. Furthermore, the above adhesive polymer may also be a curable compound. If the above adhesive polymer is curable, a reaction between the above adhesive polymer and the above polyfunctional cyclic ether compound may proceed, and it is possible to make this reaction and the cationic curing proceed competitively, or to adjust the curing stage and curing speed.

[0021] In this specification, the property of becoming hardened in the future by curing operations such as light irradiation or heating is referred to as "curability." For example, an adhesive layer that has not undergone curing operations, or an adhesive layer that is partially hardened but still has room to harden, falls under the category of "curable adhesive layer."

[0022] The above-mentioned curable adhesive composition may be thermosetting or photocurable. Examples of photocurability include active energy ray curing. Examples of active energy rays include ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, as well as ultraviolet rays, with ultraviolet rays being particularly preferred.

[0023] (Adhesive polymer) The above-mentioned adhesive polymer is included as a base polymer constituting the above-mentioned curable adhesive composition.

[0024] The above-mentioned adhesive polymer is not particularly limited, but examples include acrylic polymers, rubber polymers, silicone polymers, polyester polymers, urethane polymers, polyamide polymers, epoxy polymers, vinyl alkyl ether polymers, and fluorine polymers. Among these, acrylic polymers are preferred due to their transparency, weather resistance, adhesive reliability, and the ease with which the adhesive layer can be functionally designed due to the wide variety of monomers available. Furthermore, the curable adhesive composition of the present invention is preferably an acrylic adhesive composition in which the formed adhesive layer contains an acrylic polymer as the base polymer. Note that only one type of adhesive polymer may be used, or two or more types may be used. In addition, the epoxy polymer used as the adhesive polymer is a polymer that does not fall under the category of a polyfunctional cyclic ether compound having two or more cyclic ether groups in one molecule.

[0025] The content of the adhesive polymer in the above-mentioned curable adhesive composition is not particularly limited, but it is preferably 30% by mass or more (for example, 30 to 90% by mass) and more preferably 40% by mass or more (for example, 40 to 90% by mass) based on the total amount of solids (100% by mass) of the curable adhesive composition.

[0026] The above-mentioned acrylic polymer is a polymer that contains an acrylic monomer (a monomer having a (meth)acryloyl group in its molecule) as a monomer component constituting the polymer. That is, the above-mentioned acrylic polymer contains constituent units derived from an acrylic monomer. Note that only one type of acrylic polymer may be used, or two or more types may be used. Furthermore, the above-mentioned acrylic polymer may contain only one type of acrylic monomer as a monomer component, or it may contain two or more types.

[0027] The above acrylic polymer is preferably a polymer composed (formed) with (meth)acrylate alkyl ester as an essential monomer component. That is, the above acrylic polymer preferably contains (meth)acrylate alkyl ester as a constituent unit. In this specification, "(meth)acrylic" means "acrylic" and / or "methacrylic" (either one or both of "acrylic" and "methacrylic"), and the same applies to other terms.

[0028] The alkyl (meth)acrylate esters mentioned above are preferably alkyl (meth)acrylate esters having linear or branched alkyl groups. Note that only one type of alkyl (meth)acrylate ester may be used, or two or more types may be used.

[0029] The alkyl (meth)acrylate ester having a linear or branched alkyl group is not particularly limited, but examples include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, and (meth) Examples of alkyl (meth)acrylates having a linear or branched alkyl group having 1 to 20 carbon atoms include isononyl acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (lauryl (meth)acrylate), tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate (stearyl (meth)acrylate), isostearyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among these, alkyl (meth)acrylates having an alkyl group having 2 to 8 carbon atoms are preferred, and more preferably n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate.

[0030] The proportion of the alkyl (meth)acrylate in 100% by mass of the total amount of all monomer components constituting the above acrylic polymer is not particularly limited, but is preferably 50% by mass or more (for example, 50 to 100% by mass), more preferably 70% by mass or more, even more preferably 85% by mass or more, and particularly preferably 90% by mass or more. The above proportion is preferably less than 100% by mass, more preferably 99.5% by mass or less, even more preferably 98% by mass or less, and particularly preferably 97% by mass or less. When the above proportion is within the above range, a good quantitative balance with copolymerizable monomers is achieved, and an adhesive layer with good adhesion can be formed.

[0031] In this specification, the term "monomer component" refers to a compound having only one polymerizable functional group and does not include compounds having two or more polymerizable functional groups, such as polyfunctional (meth)acrylates.

[0032] The above-mentioned acrylic polymer may contain copolymerizable monomers as monomer components constituting the polymer, together with the above-mentioned alkyl (meth)acrylate. That is, the above-mentioned acrylic polymer may contain copolymerizable monomers as constituent units. Only one type of copolymerizable monomer may be used, or two or more types may be used.

[0033] Preferred copolymerizable monomers are carboxyl group-containing monomers and / or acid anhydride monomers. Examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of acid anhydride monomers include maleic anhydride and itaconic anhydride.

[0034] By using the above-mentioned carboxyl group-containing monomer and / or acid anhydride monomer, the acrylic polymer can easily form a crosslinked structure with an appropriate crosslink density using a crosslinking agent such as an isocyanate crosslinking agent, resulting in excellent adhesion of the adhesive layer to the adherend such as a stainless steel plate (SUS304BA plate). Among the above-mentioned carboxyl group-containing monomer and / or acid anhydride monomer, the carboxyl group-containing monomer is preferred, and (meth)acrylic acid is more preferred.

[0035] The proportion of carboxyl group-containing monomers and / or acid anhydride monomers in 100% by mass of the total amount of monomer components constituting the above acrylic polymer is not particularly limited, but is preferably 0.2% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, and particularly preferably 2% by mass or more. The above proportion is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less. When the above proportion is within the above range, a good quantitative balance with the alkyl (meth)acrylate is achieved, and an adhesive layer with good adhesion can be formed.

[0036] The copolymerizable monomers described above may further include functional group-containing monomers for the purpose of introducing crosslinking points into the acrylic polymer or enhancing the cohesive strength of the acrylic polymer. Examples of functional group-containing monomers include hydroxyl group-containing monomers, epoxy group-containing monomers, nitrogen atom-containing monomers, keto group-containing monomers, alkoxysilyl group-containing monomers, sulfonic acid group-containing monomers, and phosphate group-containing monomers. Only one type of functional group-containing monomer may be used, or two or more types may be used.

[0037] Examples of the above-mentioned hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (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; unsaturated alcohols such as vinyl alcohol and allyl alcohol; and polypropylene glycol mono(meth)acrylate.

[0038] Examples of epoxy group-containing monomers include glycidyl group-containing monomers such as glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and allyl glycidyl ether.

[0039] Examples of nitrogen atom-containing monomers include amide group-containing monomers, amino group-containing monomers, cyano group-containing monomers, and monomers having a nitrogen atom-containing ring. Examples of amide group-containing monomers include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N-methoxymethyl(meth)acrylamide, and N-butoxymethyl(meth)acrylamide. Examples of amino group-containing monomers include aminoethyl(meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, and t-butylaminoethyl(meth)acrylate. Examples of cyano group-containing monomers include acrylonitrile and methacrylonitrile. Examples of monomers having the nitrogen atom-containing ring mentioned above include N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N-(meth)acryloylmorpholine.

[0040] Examples of the above-mentioned keto group-containing monomers include diacetone(meth)acrylamide, diacetone(meth)acrylate, vinyl methyl ketone, vinyl ethyl ketone, allyl acetacetate, and vinyl acetacetate.

[0041] Examples of the above-mentioned alkoxysilyl group-containing monomers include 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, and 3-(meth)acryloxypropylmethyldiethoxysilane.

[0042] Examples of the above-mentioned sulfonic acid group-containing monomers include styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid.

[0043] Examples of the above-mentioned phosphate group-containing monomers include 2-hydroxyethyl acryloyl phosphate.

[0044] The proportion of the functional group-containing monomer in 100% by mass of the total amount of all monomer components constituting the above acrylic polymer may be, for example, 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 5% by mass or more, or 10% by mass or more. The above proportion may also be, for example, 40% by mass or less, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 2% by mass or less, and may be substantially absent. "Substantially absent" of the functional group-containing monomer means that, except in cases where the functional group-containing monomer is inevitably mixed in, the other monomers mentioned above are not actively blended.

[0045] The copolymerizable monomers mentioned above may further include other monomers. Examples of these other monomers include vinyl ester monomers such as vinyl acetate, vinyl propionate, and vinyl laurate; aromatic vinyl compounds such as styrene, substituted styrene (e.g., α-methylstyrene), and vinyltoluene; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and isobornyl (meth)acrylate; aryl (meth)acrylates (e.g., phenyl (meth)acrylate) and aryloxyalkyl (meth)acrylates (e.g., phenoxyethyl (meth)acrylate) Examples include aromatic ring-containing (meth)acrylates such as acrylate and arylalkyl (meth)acrylate (e.g., benzyl (meth)acrylate); olefin monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; isocyanate group-containing monomers such as 2-(meth)acryloyloxyethyl isocyanate; alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; and vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether.

[0046] The proportion of the above-mentioned other monomers in 100% by mass of the total amount of all monomer components constituting the above-mentioned acrylic polymer may be, for example, 0.05% by mass or more, or 0.5% by mass or more. The above proportion may also be, for example, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 2% by mass or less, and may be substantially absent. "Substantially absent" means that the above-mentioned other monomers are not actively incorporated except in cases where the above-mentioned other monomers are inevitably mixed in.

[0047] The weight-average molecular weight (Mw) of the above acrylic polymer is 10 × 10 4 It is preferable that the number be greater than or equal to 30 × 10 4 More preferably 50 × 10 4 That's all. The above Mw is 10 x 104 Above (especially 50×10 4 above), an adhesive showing good cohesiveness can be easily obtained. Also, the above Mw is preferably 300×10 4 or less, more preferably 250×10 4 or less, still more preferably 200×10 4 or less. When the above Mw is 300×10 4 or less, it is easy to form an adhesive showing appropriate fluidity (mobility of polymer chains), so the flex resistance is more excellent. The above weight average molecular weight is measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene conversion.

[0048] The glass transition temperature (Tg) of the above acrylic polymer is preferably 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower. When the above glass transition temperature is 0°C or lower, even when repeated bending is received in a low temperature environment, it is difficult for the bent part to break or have marks, or for the adhesive sheet to peel off. The above glass transition temperature is preferably -80°C or higher, more preferably -70°C or higher, still more preferably -66°C or higher, particularly preferably -60°C or higher.

[0049] The above glass transition temperature is a value calculated based on the following formula (X) (Fox formula). 1 / Tg = W1 / Tg1 + W2 / Tg2 + ··· + Wn / Tgn (X) [In formula (X), Tg is the glass transition temperature of the polymer (unit: K), Tgi (i = 1, 2, ··· n) is the glass transition temperature (unit: K) when monomer i forms a homopolymer, and Wi (i = 1, 2, ··· n) represents the mass fraction of monomer i in all monomer components.] The above formula (X) is a calculation formula when the polymer is composed of n types of monomer components of monomer 1, monomer 2, ···, monomer n.

[0050] In this specification, "glass transition temperature (Tg) when a homopolymer is formed" (sometimes simply referred to as "Tg of the homopolymer") means "the glass transition temperature (Tg) of the monomer homopolymer," and specifically, the numerical value is given in the "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1987). For monomers not listed in the above literature, the Tg of the homopolymer refers to the value obtained by, for example, the following measurement method (see Japanese Patent Publication No. 2007-51271), except for monomers having a polyorganosiloxane skeleton. That is, 100 parts by mass of monomer, 0.2 parts by mass of 2,2'-azobisisobutyronitrile, and 200 parts by mass of ethyl acetate as a polymerization solvent are added to a reactor equipped with a thermometer, stirrer, nitrogen inlet tube, and reflux condenser, and the mixture is stirred for 1 hour while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, the temperature is raised to 63°C and the reaction is carried out for 10 hours. Next, the mixture is cooled to room temperature to obtain a homopolymer solution with a solid content of 33% by mass. Then, this homopolymer solution is cast onto a release liner and dried to prepare a test sample (sheet-like homopolymer) with a thickness of approximately 2 mm. This test sample is then punched out into a disc shape with a diameter of 7.9 mm, sandwiched between parallel plates, and the viscoelasticity is measured using a viscoelasticity tester (product name "ARES", manufactured by Rheometrics) in shear mode while applying a shear strain at a frequency of 1 Hz, in a temperature range of -70 to 150°C, and at a heating rate of 5°C / min. The peak top temperature of tanδ is taken as the Tg of the homopolymer.

[0051] The above-mentioned acrylic polymer is obtained by polymerizing a composition containing at least an acrylic monomer. While not particularly limited, these polymerization methods include solution polymerization, emulsion polymerization, bulk polymerization, thermal polymerization, and polymerization by active energy ray irradiation (active energy ray polymerization). Among these, bulk polymerization, thermal polymerization, and active energy ray polymerization are preferred in terms of transparency of the adhesive layer and cost. Furthermore, the resulting acrylic polymer may be a random copolymer, block copolymer, graft copolymer, or any other type.

[0052] Various common solvents may be used in the polymerization of monomer components. Examples of such solvents include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. One or more of these solvents may be used.

[0053] The polymerization initiators, chain transfer agents, emulsifiers, etc., used in the radical polymerization of monomer components are not particularly limited and can be selected and used as appropriate. The weight-average molecular weight of the polymer can be controlled by the amount of polymerization initiator and chain transfer agent used and the reaction conditions, and the appropriate amounts used are adjusted according to the type of agent.

[0054] Depending on the type of polymerization reaction, various polymerization initiators can be used for the polymerization of monomer components, including thermal polymerization initiators and photopolymerization initiators (photoinitiators). One type of polymerization initiator may be used, or two or more types may be used.

[0055] The above-mentioned thermal polymerization initiators are not particularly limited, but examples include azo polymerization initiators, peroxide polymerization initiators (e.g., persulfates such as dibenzoyl peroxide, tert-butyl permaleate, potassium persulfate, benzoyl peroxide, hydrogen peroxide, etc.), substituted ethane initiators such as phenyl-substituted ethane, aromatic carbonyl compounds, redox polymerization initiators, etc. Among these, the azo polymerization initiator disclosed in Japanese Patent Application Publication No. 2002-69411 is preferred. Examples of the above-mentioned azo polymerization initiators include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis(2-methylpropionic acid)dimethyl, and 4,4'-azobis-4-cyanovaleric acid. The amount of thermal polymerization initiator used can be the usual amount, for example, it can be selected from a range of 0.01 to 5 parts by mass, preferably 0.05 to 3 parts by mass, per 100 parts by mass of monomer component.

[0056] The above-mentioned photopolymerization initiators are not particularly limited, but examples include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, and thioxanthone-based photopolymerization initiators. Other examples include acylphosphine oxide-based photopolymerization initiators and titanocene-based photopolymerization initiators. Examples of the above-mentioned benzoin ether-based photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, and anisole methyl ether. Examples of the above acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone. Examples of the above α-ketol-based photopolymerization initiators include 2-methyl-2-hydroxypropiophenone and 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Examples of the above aromatic sulfonyl chloride-based photopolymerization initiators include 2-naphthalenesulfonyl chloride. Examples of the above photoactive oxime-based photopolymerization initiators include 1-phenyl-1,1-propanedione-2-(O-ethoxycarbonyl)-oxime. Examples of the above benzoin-based photopolymerization initiators include benzoin. Examples of the above benzyl-based photopolymerization initiators include benzyl. Examples of the benzophenone-based photopolymerization initiators include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, and α-hydroxycyclohexylphenyl ketone. Examples of the ketal-based photopolymerization initiators include benzyldimethyl ketal.Examples of the thioxanthone-based photopolymerization initiators include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone. Examples of the acylphosphine oxide-based photopolymerization initiators include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide. Examples of the titanocene-based photopolymerization initiators include bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)-phenyl)titanium. The amount of photopolymerization initiator used can be the usual amount, for example, it can be selected from a range of 0.01 to 5 parts by mass, preferably 0.05 to 3 parts by mass, per 100 parts by mass of monomer component.

[0057] (Polyfunctional cyclic ether compounds) The above-mentioned polyfunctional cyclic ether compound is a compound having two or more cyclic ether groups in one molecule. The above-mentioned polyfunctional cyclic ether compound polymerizes when the cyclic ether groups react with each other due to the acid generated from the acid generator. The number of cyclic ether groups in the above-mentioned polyfunctional cyclic ether compound is, for example, 2 to 20, preferably 2 to 15.

[0058] The above cyclic ether group preferably has one oxygen atom. The above cyclic ether group preferably contains an epoxy group and / or an oxetanyl group. Furthermore, the above cyclic ether groups in the above polyfunctional cyclic ether compound may be the same or different. In this specification, compounds having an epoxy group may be referred to as "epoxy compounds," and compounds having an oxetanyl group may be referred to as "oxetanyl compounds."

[0059] The above polyfunctional cyclic ether compound may be used by one or by two or more. In particular, the polyfunctional cyclic ether compound is preferably an epoxy compound or an oxetanyl compound, and preferably contains both an epoxy compound and an oxetanyl compound.

[0060] When the above polyfunctional cyclic ether compound contains both an epoxy compound and an oxetanyl compound, the mass ratio of the epoxy compound to the oxetanyl compound [epoxy compound / oxetanyl compound] is preferably 0.7 to 7, more preferably 0.8 to 6, even more preferably 1 to 5, even more preferably 1.5 to 4, and particularly preferably 2 to 3. When the above mass ratio is within the above range, the initial reaction during curing can be delayed, and the curing rate over time can be accelerated. For this reason, the above adhesive composition can be preferably used in applications where curing is required after bonding.

[0061] Examples of the epoxy compounds mentioned above include aromatic epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol AF type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, trishydroxyphenylmethane type epoxy resin, and tetraphenyloleethane type epoxy resin; alicyclic epoxy resins such as hydrogenated bisphenol A type epoxy resin; and aliphatic epoxy resins such as hydantoin type epoxy resin, trisglycidyl isocyanurate type epoxy resin, and glycidylamine type epoxy resin. Among the epoxy resins mentioned above, alicyclic epoxy resins are preferred from the viewpoint of having a low amount of halogen contamination during the manufacturing process and superior curability by cationic agents.

[0062] Examples of the oxetane compounds mentioned above include bis{[1-ethyl(3-oxetanyl)]methyl} ether, 4,4'-bis[(3-ethyl-3-oxetanyl)methoxymethyl]bicyclohexyl, 1,4-bis[(3-ethyl-3-oxetanyl)methoxymethyl]cyclohexane, 1,4-bis{[(3-ethyl-3-oxetanyl)methoxy]methyl}benzene, 3-ethyl-3-{[(3-ethyloxetan-3-yl)methoxy]methyl)}oxetane, xylylenebisoxetane, 3-ethyl-3-{[3-(triethoxysilyl)propoxy]methyl}oxetane, oxetanylsilsesquioxane, oxetanyl silicate, and phenol novolac oxetane.

[0063] The equivalent amount of the cyclic ether group in the above polyfunctional cyclic ether compound is preferably 150 to 900 g / eq, more preferably 150 to 700 g / eq.

[0064] The content of the polyfunctional cyclic ether compound in the above curable adhesive composition is 10 to 100 parts by mass, preferably 30 to 90 parts by mass, more preferably 40 to 85 parts by mass, even more preferably 50 to 80 parts by mass, and particularly preferably 60 to 75 parts by mass, based on 100 parts by mass of the total amount of the adhesive polymer. If the content is 10 parts by mass or more, the curability of the adhesive layer formed by the curable adhesive composition can be sufficiently achieved. If the content is 100 parts by mass or less, curing shrinkage during curing can be suppressed, and the adhesion to the adherend after curing is excellent.

[0065] (Acid generator) The type of acid generator described above is appropriately selected depending on the type of curing of the curable adhesive composition, and examples include thermal acid generators and photoacid generators. One type of acid generator may be used, or two or more types may be used.

[0066] A thermal acid generator is a chemical species that generates acid when heated. Examples of thermal acid generators include sulfonium salts and phosphonium salts. Such salts include salts of cations and anions. Examples of cations include benzyl(4-hydroxyphenyl)methylsulfonium, (4-acetoxyphenyl)dimethylsulfonium, (4-hydroxyphenyl)dimethylsulfonium, (2-methylbenzyl)(4-hydroxyphenyl)methylsulfonium, (4-acetoxyphenyl)(2-methylbenzyl)methylsulfonium, (1-naphthylmethyl)(4-hydroxyphenyl)methylsulfonium, and benzyl(4-acetoxyphenyl)methylsulfonium. Examples of anions include tris(pentafluoroethyl)trifluorophosphate, hexafluorophosphate, tetrakis(pentafluorophenyl)borate, hexafluoroantimonate, p-toluenesulfonate, dodecylbenzenesulfonate, trifluoromethanesulfonate, and perfluorobutanesulfonate.

[0067] Commercially available thermal acid generators include, for example, the following products: "Sun-Aid SI-45L", "Sun-Aid SI-60L", "Sun-Aid SI-80L", "Sun-Aid SI-100L", "Sun-Aid SI-110L", "Sun-Aid SI-150L", "Sun-Aid SI-45", "Sun-Aid SI-60", "Sun-Aid SI-80", "Sun-Aid SI-100", "Sun-Aid SI-110", "Sun-Aid SI-150", "Sun-Aid SI-300", "Sun-Aid SI-360", "Sun-Aid SI-B2A", "Sun-Aid SI-B3", "Sun-Aid SI-B3A", and "Sun-Aid Examples include "SI-B4", "San-Aid SI-B5" (both manufactured by Sanshin Chemical Industry Co., Ltd.), "PP-33", "CP-66", and "CP-77" (all manufactured by ADEKA Corporation).

[0068] A photoacid generator is a chemical species that generates acid upon irradiation with light. For example, a photoacid generator is excited by irradiation with light of a predetermined wavelength or wavelength range, triggering an acid generation reaction and generating acid. This acid generation reaction is, for example, a decomposition reaction of the photoacid generator. The wavelength of light that triggers the acid generation reaction varies depending on the type of photoacid generator. A photoacid generator does not substantially generate acid using the heat required to generate acid from a thermal acid generator.

[0069] Examples of the above-mentioned photoacid generators include sulfonium salts, iodonium salts, selenium salts, ammonium salts, phosphonium salts, and salts of transition metal complex ions and anions. Among these photoacid generators, sulfonium salts are preferred from the viewpoint of producing less discoloration of the adhesive sheet after curing, having excellent light absorption efficiency in the long wavelength range, and being activatable at low energy.

[0070] The above sulfonium salts are salts in which the cation part is sulfonium. Examples of the above sulfonium salts include [4-(4-biphenylylthio)phenyl]-4-biphenylylphenylsulfonium tris(pentafluoroethyl)trifluorophosphate, triphenylsulfonium salt, tri-p-tolylsulfonium salt, tri-o-tolylsulfonium salt, tris(4-methoxyphenyl)sulfonium salt, 1-naphthyldiphenylsulfonium salt, 2-naphthyldiphenylsulfonium salt, tris(4-fluorophenyl)sulfonium salt, tri-1-naphthylsulfonium salt, tri-2-naphthylsulfonium salt, tris(4-hydroxyphenyl)sulfonium salt, dif Examples of salts in which the cation portion is aromatic sulfonium include triarylsulfonium salts such as phenyl[4-(phenylthio)phenyl]sulfonium salt and 4-(p-tolylthio)phenyldi-(p-phenyl)sulfonium salt; diarylsulfonium salts such as diphenylphenacylsulfonium salt, diphenyl4-nitrophenacylsulfonium salt, diphenylbenzylsulfonium salt, and diphenylmethylsulfonium salt; and monoarylsulfonium salts such as phenylmethylbenzylsulfonium salt, 4-hydroxyphenylmethylbenzylsulfonium salt, and 4-methoxyphenylmethylbenzylsulfonium salt. In addition, examples of salts in which the cation portion is aliphatic sulfonium include trialkylsulfonium salts such as dimethylphenacylsulfonium salt, phenacyltetrahydrothiophenium salt, and dimethylbenzylsulfonium salt. Among the above sulfonium salts, it is preferable that the cation portion is aromatic sulfonium from the viewpoint of less discoloration of the adhesive sheet after curing, excellent light absorption efficiency in the long wavelength range, and low energy activation.

[0071] The iodonium salts mentioned above are salts in which the cation part is iodonium. Examples of the iodonium salts mentioned above include the product name "UV9380C" (manufactured by Momentive Performance Materials Japan LLC, bis(4-dodecylphenyl)iodonium = hexafluoroantimonate 45% alkylglycidyl ether solution), the product name "RHODORSIL PHOTOINITIATOR 2074" (manufactured by Rhodia Japan Co., Ltd., tetrakis(pentafluorophenyl)borate = [(1-methylethyl)phenyl](methylphenyl)iodonium), the product name "WPI-124" (manufactured by Wako Pure Chemical Industries, Ltd.), diphenyliodonium salt, di-p-tolyliodonium salt, bis(4-dodecylphenyl)iodonium salt, and bis(4-methoxyphenyl)iodonium salt.

[0072] The selenium salts mentioned above are salts in which the cation part is selenium. Examples of the selenium salts include triarylselenium salts such as triphenylselenium salt, tri-p-tolylselenium salt, tri-o-tolylselenium salt, tris(4-methoxyphenyl)selenium salt, and 1-naphthyldiphenylselenium salt; diarylselenium salts such as diphenylphenacylselenium salt, diphenylbenzylselenium salt, and diphenylmethylselenium salt; monoarylselenium salts such as phenylmethylbenzylselenium salt; and trialkylselenium salts such as dimethylphenacylselenium salt.

[0073] The above ammonium salts are salts in which the cation part is ammonium. Examples of the above ammonium salts include tetraalkylammonium salts such as tetramethylammonium salt, ethyltrimethylammonium salt, diethyldimethylammonium salt, triethylmethylammonium salt, tetraethylammonium salt, trimethyl-n-propylammonium salt, and trimethyl-n-butylammonium salt; pyrrolidium salts such as N,N-dimethylpyrrolidium salt and N-ethyl-N-methylpyrrolidium salt; imidazolinium salts such as N,N'-dimethylimidazolinium salt and N,N'-diethylimidazolinium salt; and N,N'-dimethyltetrahydropyrimidium salt and N,N'-diethyl Examples include tetrahydropyrimidium salts such as trahydropyrimidium salt; morpholinium salts such as N,N-dimethylmorpholinium salt and N,N-diethylmorpholinium salt; piperidinium salts such as N,N-dimethylpiperidinium salt and N,N-diethylpiperidinium salt; pyridinium salts such as N-methylpyridinium salt and N-ethylpyridinium salt; imidazolium salts such as N,N'-dimethylimidazolium salt; quinolium salts such as N-methylquinolium salt; isoquinolium salts such as N-methylisoquinolium salt; thiazonium salts such as benzylbenzothiazonium salt; and acridium salts such as benzylacridium salt.

[0074] The above-mentioned phosphonium salt is a salt in which the cation part is phosphonium. Examples of the above-mentioned phosphonium salt include tetraarylphosphonium salts such as tetraphenylphosphonium salt, tetra-p-tolylphosphonium salt, and tetrakis(2-methoxyphenyl)phosphonium salt; triarylphosphonium salts such as triphenylbenzylphosphonium salt; and tetraalkylphosphonium salts such as triethylbenzylphosphonium salt, tributylbenzylphosphonium salt, tetraethylphosphonium salt, tetrabutylphosphonium salt, and triethylphenacylphosphonium salt.

[0075] Examples of the above transition metal complex ion salts include (η 5 -cyclopentadienyl)(η 6 -toluene)Cr+ , (η 5 -cyclopentadienyl)(η 6 -Xylene)Cr + Salts of chromium complex cations such as (η 5 -cyclopentadienyl)(η 6 -Toluene)Fe + , (η 5 -cyclopentadienyl)(η 6 -xylene)Fe + Examples include salts of iron complex cations.

[0076] Examples of anions that make up the aforementioned salt include SbF 6- , PF 6- BF 4- , (CF3CF2)3PF 3- , (CF3CF2CF2)3PF 3- (C6F5)4B - (C6F5)4Ga - , sulfonate anions (trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, nonafluorobutanesulfonate anion, methanesulfonate anion, benzenesulfonate anion, p-toluenesulfonate anion, etc.), (CF3SO2)3C - (CF3SO2)2N - Examples include perhalate ions, halogenated sulfonate ions, sulfate ions, carbonate ions, aluminate ions, hexafluorobismuth ions, carboxylate ions, arylborate ions, thiocyanate ions, and nitrate ions.

[0077] Examples of commercially available photoacid generators include the product names "CPI-100, CPI-100P", "CPI-101A", "CPI-200K", "CPI-210S", "IK-1", "IK-2", "CPI-310B", "CPI-310FG", and "CPI-410S" (all manufactured by Sunapro Co., Ltd.), as well as "SP-056", "SP-066", "SP-130", "SP-140", "SP-150", "SP-170", "SP-171", and "SP-172" (manufactured by ADEKA Corporation).

[0078] The content of the acid generator in the above curable adhesive composition is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, and even more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the total amount of the adhesive polymer. When the content is 0.01 parts by mass or more, the curing of the polyfunctional cyclic ether compound proceeds efficiently. When the content is 10 parts by mass or less, curing shrinkage can be made less likely to occur.

[0079] (Crosslinking agent) The above curable adhesive composition may contain a crosslinking agent. If the adhesive polymer has functional groups that can react with the crosslinking agent, the adhesive polymer can be crosslinked and cured during curing. The crosslinking agent may be used by one type or by two or more types.

[0080] The above crosslinking agents are not particularly limited, but examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, amine-based crosslinking agents, hydrazine-based crosslinking agents, silicone-based crosslinking agents, and silane-based crosslinking agents (silane coupling agents). Among the above crosslinking agents, it is preferable to include isocyanate-based crosslinking agents.

[0081] The content of the crosslinking agent is not particularly limited, but is preferably 0.001 to 20 parts by mass, more preferably 0.01 to 15 parts by mass, even more preferably 0.15 to 10 parts by mass, even more preferably 0.1 to 8 parts by mass, even more preferably 0.2 to 6 parts by mass, even more preferably 0.5 to 4 parts by mass, and especially preferably 1 to 3 parts by mass, per 100 parts by mass of the total amount of the adhesive polymer.

[0082] The above-mentioned isocyanate-based crosslinking agents are compounds (polyfunctional isocyanate compounds) having an average of two or more isocyanate groups per molecule. Examples of the above-mentioned isocyanate-based crosslinking agents include aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates.

[0083] Examples of the above-mentioned aliphatic polyisocyanates include 1,2-ethylene diisocyanate; tetramethylene diisocyanates such as 1,2-tetramethylene diisocyanate, 1,3-tetramethylene diisocyanate, and 1,4-tetramethylene diisocyanate; hexamethylene diisocyanates such as 1,2-hexamethylene diisocyanate, 1,3-hexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, 1,5-hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, and 2,5-hexamethylene diisocyanate; and 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, and lysine diisocyanate.

[0084] Examples of the above-mentioned alicyclic polyisocyanates include isophorone diisocyanate; cyclohexyl diisocyanates such as 1,2-cyclohexyl diisocyanate, 1,3-cyclohexyl diisocyanate, and 1,4-cyclohexyl diisocyanate; cyclopentyl diisocyanates such as 1,2-cyclopentyl diisocyanate and 1,3-cyclopentyl diisocyanate; hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0085] Examples of the above aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, and 2,2'-diphenylpropane-4,4'-diisocyanate. Examples include 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropanediisocyanate, m-phenylenediisocyanate, p-phenylenediisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, xylylene-1,4-diisocyanate, and xylylene-1,3-diisocyanate.

[0086] In addition, commercially available isocyanate-based crosslinking agents include, for example, trimethylolpropane / tolylene diisocyanate adduct (product name "Coronate L", manufactured by Tosoh Corporation), trimethylolpropane / hexamethylene diisocyanate adduct (product name "Coronate HL", manufactured by Tosoh Corporation), trimethylolpropane / xylylene diisocyanate adduct (product name "Takenate D-110N", manufactured by Mitsui Chemicals, Inc.), and tolylene diisocyanate (product name "Takenate D-101E", manufactured by Mitsui Chemicals, Inc.).

[0087] When an isocyanate-based crosslinking agent is used as the crosslinking agent, the content of the isocyanate-based crosslinking agent is not particularly limited, but is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, per 100 parts by mass of the total amount of the adhesive polymer. The content is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 5 parts by mass or less.

[0088] Examples of the epoxy crosslinking agents (polyfunctional epoxy compounds) mentioned above include N,N,N',N'-tetraglycidyl-m-xylenediline, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and sorbitol polyglycidyl ether. Examples of epoxy crosslinking agents include diglycidyl ethers, glycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, polyglycerol polyglycidyl ethers, sorbitan polyglycidyl ethers, trimethylolpropane polyglycidyl ethers, diglycidyl adipate esters, diglycidyl o-phthalate esters, triglycidyl-tris(2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ethers, bisphenol-S-diglycidyl ethers, and epoxy resins having two or more epoxy groups in their molecules. In addition, commercially available epoxy crosslinking agents such as the trade name "Tetrad C" (manufactured by Mitsubishi Gas Chemical Company, Inc.) can also be used.

[0089] When an epoxy-based crosslinking agent is used as the crosslinking agent, the content of the epoxy-based crosslinking agent is not particularly limited, but is preferably more than 0 parts by mass and 1 part by mass or less per 100 parts by mass of the total amount of the adhesive polymer, more preferably 0.001 to 0.5 parts by mass, even more preferably 0.002 to 0.2 parts by mass, even more preferably 0.005 to 0.1 parts by mass, even more preferably 0.008 to 0.1 parts by mass, and particularly preferably 0.009 to 0.05 parts by mass.

[0090] As the above-mentioned peroxide-based crosslinking agent, any agent that generates radical active species upon heating to promote crosslinking of the adhesive polymer can be used as appropriate. However, considering workability and stability, it is preferable to use a peroxide with a 1-minute half-life temperature of 80 to 160°C, and more preferably a peroxide with a half-life temperature of 90 to 140°C.

[0091] Examples of the above peroxide-based crosslinking agents include di(2-ethylhexyl)peroxydicarbonate (half-life temperature at 1 minute: 90.6°C), di(4-t-butylcyclohexyl)peroxydicarbonate (half-life temperature at 1 minute: 92.1°C), di-sec-butylperoxydicarbonate (half-life temperature at 1 minute: 92.4°C), t-butylperoxyneodecanoate (half-life temperature at 1 minute: 103.5°C), t-hexylperoxypivalate (half-life temperature at 1 minute: 109.1°C), t-butylperoxypivalate (half-life temperature at 1 minute: 110.3°C), and dilauroyl peroxy Examples include peroxide (half-life temperature at 1 minute: 116.4°C), di-n-octanoyl peroxide (half-life temperature at 1 minute: 117.4°C), 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate (half-life temperature at 1 minute: 124.3°C), di(4-methylbenzoyl) peroxide (half-life temperature at 1 minute: 128.2°C), dibenzoyl peroxide (half-life temperature at 1 minute: 130.0°C), t-butyl peroxyisobutyrate (half-life temperature at 1 minute: 136.1°C), and 1,1-di(t-hexylperoxy)cyclohexane (half-life temperature at 1 minute: 149.2°C).

[0092] The half-life of the peroxide-based crosslinking agent mentioned above is an indicator of the decomposition rate of the peroxide, and refers to the time it takes for the amount of remaining peroxide to be halved. The decomposition temperature required to obtain a half-life at any given time, and the half-life time at any given temperature, are described in manufacturer catalogs, for example, in NOF Corporation's "Organic Peroxide Catalog, 9th Edition (May 2003)". The amount of remaining decomposed peroxide after reaction treatment can be measured, for example, by HPLC (High-Performance Liquid Chromatography). More specifically, for example, approximately 0.2 g of the adhesive after reaction treatment is taken, immersed in 10 ml of ethyl acetate, and extracted by shaking at 120 rpm at 25°C for 3 hours, then left to stand at room temperature for 3 days. Next, 10 ml of acetonitrile is added, shaken at 120 rpm at 25°C for 30 minutes, filtered through a membrane filter (0.45 μm), and approximately 10 μl of the resulting extract is injected into HPLC for analysis to determine the amount of peroxide after reaction treatment.

[0093] When a peroxide-based crosslinking agent is used as the crosslinking agent, the content of the crosslinking agent is not particularly limited, but is preferably 2 parts by mass or less, more preferably 0.02 to 2 parts by mass, even more preferably 0.05 to 1.5 parts by mass, even more preferably 0.05 to 1 part by mass, and particularly preferably 0.1 to 1 part by mass, per 100 parts by mass of the total amount of the adhesive polymer.

[0094] Furthermore, organic crosslinking agents or polyfunctional metal chelates may be used in combination as the crosslinking agent. Polyfunctional metal chelates are those in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. Examples of atoms in the organic compound that form covalent or coordinate bonds include oxygen atoms, and examples of organic compounds include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds.

[0095] The above-mentioned curable adhesive composition may contain a coloring agent. The coloring agent may be a pigment or a dye. Examples of coloring agents include black coloring agents, cyan coloring agents, magenta coloring agents, and yellow coloring agents. From the viewpoint of superior visibility and design, black coloring agents are preferred. The composition may contain only one coloring agent or two or more.

[0096] Examples of black colorants include carbon black, carbon nanotubes, graphite, copper oxide, manganese dioxide, azo pigments such as azomethine azoblack, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite, magnetite, chromium oxide, iron oxide, molybdenum disulfide, complex oxide black pigments, anthraquinone-based organic black dyes, and azo-based organic black dyes. Examples of carbon black include furnace black, channel black, acetylene black, thermal black, and lamp black. Examples of black colorants include CI Solvent Black 3, 7, 22, 27, 29, 34, 43, and 70; CI Direct Black 17, 19, 22, 32, 38, 51, and 71; CI Acid Black 1, 2, 24, 26, 31, 48, 52, 107, 109, 110, 119, and 154; CI Disperse Black 1, 3, 10, and 24; and CI Pigment Black 1 and 7.

[0097] Examples of cyan-based colorants include CI Solvent Blue 25, 36, 60, 70, 93, 95; CI Acid Blue 6, 45; CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 15:5, 15:6, 16, 17, 17:1, 18, 22, 25, 56, 60, 63, 65, 66; CI Bat Blue 4, 60, and CI Pigment Green 7.

[0098] Examples of magenta-based colorants include CI Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63, 81, 82, 83, 84, 100, 109, 111, 121, 122; CI Disperse Red 9; CI Solvent Violet 8, 13, 14, 21, 27; CI Disperse Examples include Violet 1; CI Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40; CI Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, 28, etc. Furthermore, as magenta-based colorants, for example, CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 42, 48:1, Same 48:2, same 48:3, same 48:4, same 49, same 49:1, same 50, same 51, same 52, same 52:2, same 53:1, same 54, same 55, same 56, same 57:1, same 58, same 60, same 60:1, same 63, same 63:1, same 63:2, same 64, same 64:1, same 67, same 68, same 81, same 83, same 87, same 88, same 89, same 90, same 92, same 101 , 104, 105, 106, 108, 112, 114, 122, 123, 139, 144, 146, 147, 149, 150, 151, 163, 166, 168, 170, 171, 172, 175, 176, 177, 178, 179, 184, 185, 187, 190 Examples include 193, 202, 206, 207, 209, 219, 222, 224, 238, and 245; CI Pigment Violet 3, 9, 19, 23, 31, 32, 33, 36, 38, 43, and 50; CI Bat Red 1, 2, 10, 13, 15, 23, 29, and 35.

[0099] Examples of yellow colorants include CI Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162; CI Pigment Orange 31, 43; CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 24, 34, 35, 37, 42, 53, 55, 65, 73, 74. Examples include 75, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 113, 114, 116, 117, 120, 128, 129, 133, 138, 139, 147, 150, 151, 153, 154, 155, 156, 167, 172, 173, 180, 185, 195; CI Bat Yellow 1, 3, 20, etc.

[0100] The above curable adhesive composition may optionally further contain additives such as solvents, crosslinking accelerators, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), anti-aging agents, antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, foil-like materials, rust inhibitors, and oligomers, to the extent that they do not impair the effects of the present invention. Each of the above additives may be used individually or in combination of two or more.

[0101] The above-mentioned curable adhesive composition may be in any form, for example, an emulsion type, a solvent type (solution type), or a hot melt type. Among these, the solvent type is preferred because it is easier to obtain an adhesive layer with excellent productivity.

[0102] The curable adhesive composition of the present invention makes it possible to form an adhesive layer that has high adhesion to the adherend after curing. Therefore, when an adhesive sheet having the above adhesive layer is bonded to an adherend and then cured, the curing shrinkage of the adhesive layer is suppressed, high adhesive strength is maintained, and it is difficult to peel off from the adherend. In particular, it is difficult to peel off even when the adhesive layer is used in an area that is subjected to repeated bending, or when the adherend has an uneven surface.

[0103] [Adhesive layer] An adhesive layer can be formed using the above-described curable adhesive composition. The adhesive layer formed using the curable adhesive composition of the present invention may be referred to as "the adhesive layer of the present invention." The adhesive layer can be produced, for example, by applying the above-described curable adhesive composition to the release surface of a release liner or a substrate to form an adhesive composition layer, and then solidifying the adhesive composition layer by desolvation by heating or the like.

[0104] For applying (coating) the above-mentioned curable adhesive composition, known coating methods may be used. For example, coaters such as gravure roll coaters, reverse roll coaters, kiss roll coaters, dip roll coaters, bar coaters, knife coaters, spray coaters, comma coaters, and direct coaters may be used.

[0105] The adhesive layer of the present invention is curable. The adhesive layer of the present invention may be thermosetting or photocurable. Examples of photocurability include active energy ray curing. Examples of active energy rays include ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron beams, and ultraviolet rays, with ultraviolet rays being particularly preferred.

[0106] The adhesive layer of the present invention is cured, and the adhesive surface is bonded to a stainless steel plate. After being left for 30 minutes in an environment of 23°C and 50%RH, the 180° peel adhesive force at a tensile speed of 300 mm / min is preferably 3.0 N / 25 mm or more, more preferably 5.0 N / 25 mm or more, and even more preferably 7.0 N / 25 mm or more. When the above peel adhesive force is 3.0 N / 25 mm or more, the adhesion to the adherend is excellent. The above peel adhesive force is, for example, 50.0 N / 25 mm or less. When the adhesive sheet equipped with the adhesive layer of the present invention is a substrate-less type adhesive sheet, it is preferable to back the adhesive surface opposite the adhesive surface on which the peel adhesive force is measured with a plastic film such as a PET film. Detailed methods are shown in the examples.

[0107] The above peel-off adhesive strength can be adjusted by appropriately selecting the type and content of adhesive polymers, the type and content of polyfunctional cyclic ether compounds, the type and content of crosslinking agents and acid generators in the curable adhesive composition.

[0108] In this specification, the adhesive surface of the adhesive layer of the present invention having the above-mentioned peel-off adhesive strength may be referred to as "adhesive surface (X)".

[0109] The shear adhesive strength measured after curing the adhesive layer of the present invention, bonding the adhesive surface (adhesive surface (X)) to a stainless steel plate, and leaving it for two days in an environment of 23°C and 50% RH, at a tensile speed of 10 mm / min and a peel angle of 0°, is preferably 1.5 MPa or higher, more preferably 1.6 MPa or higher, even more preferably 1.8 MPa or higher, and even more preferably 2.0 MPa or higher. When the above shear adhesive strength is 1.5 MPa or higher, the state in which the adhesive layer is bonded to the adherend is maintained even more effectively. The above shear adhesive strength is, for example, 10.0 MPa or lower. When the adhesive sheet equipped with the adhesive layer of the present invention is a substrate-less type adhesive sheet, it is preferable to back the adhesive surface opposite the adhesive surface on which the shear adhesive strength is measured with a thin metallic film such as stainless steel foil. Detailed methods are shown in the examples.

[0110] The above-mentioned shear adhesive strength can be adjusted by appropriately selecting the type and content of adhesive polymers, the type and content of polyfunctional cyclic ether compounds, the type and content of crosslinking agents and acid generators in the curable adhesive composition.

[0111] The thickness of the adhesive layer of the present invention is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 100 μm or less. Even when the thickness is as thin as 200 μm or less, the adhesive layer of the present invention exhibits excellent tackiness and adhesion to the adherend. The above thickness is not particularly limited, but from the viewpoint of superior tackiness and adhesion to the adherend, it is preferably 6 μm or more, more preferably 10 μm or more, even more preferably 12 μm or more, and particularly preferably 15 μm or more.

[0112] [Adhesive sheet] An adhesive sheet can be obtained using the adhesive layer of the present invention. An adhesive sheet comprising the adhesive layer of the present invention may be referred to as "the adhesive sheet of the present invention." The above adhesive sheet may be a double-sided adhesive sheet in which both sides are adhesive layer surfaces, or a single-sided adhesive sheet in which only one side is an adhesive layer surface. Among these, a double-sided adhesive sheet is preferred from the viewpoint of bonding two members together. In this specification, the term "adhesive sheet" also includes tape-like materials, i.e., "adhesive tape." In this specification, the surface of the adhesive layer may be referred to as the "adhesive surface."

[0113] The adhesive sheet of the present invention may be a so-called "substrate-less type" adhesive sheet that does not have a base material (substrate layer), or it may be an adhesive sheet that has a base material. In this specification, a "substrate-less type" adhesive sheet may be referred to as a "substrate-less adhesive sheet," and an adhesive sheet that has a base material may be referred to as a "substrate-attached adhesive sheet." Examples of the above-mentioned substrate-less adhesive sheet include a double-sided adhesive sheet consisting only of the adhesive layer of the present invention, and a double-sided adhesive sheet consisting of the adhesive layer of the present invention and other adhesive layers (adhesive layers other than the adhesive layer of the present invention). Examples of the above-mentioned substrate-attached adhesive sheet include a single-sided adhesive sheet having the adhesive layer of the present invention on one side of the base material, a double-sided adhesive sheet having the adhesive layer of the present invention on both sides of the base material, and a double-sided adhesive sheet having the adhesive layer of the present invention on one side of the base material and other adhesive layers on the other side. The above-mentioned "substrate (substrate layer)" refers to the support, and is the part that is attached to the adherend together with the adhesive layer when the adhesive sheet of the present invention is used (attached) to an adherend. The release liner that is peeled off when the adhesive sheet is used (applied) is not included in the above-mentioned substrate.

[0114] Figure 1 is a cross-sectional view showing one embodiment of the adhesive sheet of the present invention. The adhesive sheet 1 shown in Figure 1 is a substrate-less double-sided adhesive sheet consisting of a single layer of adhesive layer 2, which is the adhesive layer of the present invention, and a release liner 3 and a release liner 4 are provided on both adhesive surfaces, respectively.

[0115] The adhesive sheet of the present invention may comprise only one or more adhesive layers of the present invention. When comprising two or more adhesive layers of the present invention, the multiple adhesive layers of the present invention may be the same adhesive layer, or they may be adhesive layers with different compositions, thicknesses, physical properties, etc.

[0116] (base material) The above-mentioned substrate is an element that functions as a support in an adhesive sheet. The above-mentioned substrate may be a single layer or a laminate of the same or different types of substrates.

[0117] Examples of the above-mentioned substrates include plastic substrates (e.g., plastic films), porous materials such as paper, cloth, and nonwoven fabrics, nets, and foamed sheets. Plastic substrates (particularly plastic films) are preferred as the above-mentioned substrate. Furthermore, it is preferable that the above-mentioned substrate be a non-foamed sheet.

[0118] Examples of resins constituting the above-mentioned plastic substrate include polyolefin resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolypropylene, polybutene, polymethylpentene, ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, and ethylene-hexene copolymer; polyurethane resins; rubber resins (natural rubber, synthetic rubber, mixtures thereof, etc.): polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, and polybutylene terephthalate (PBT); polycarbonate; polyimide; polyether ether ketone; polyetherimide; polyamides such as aramid and fully aromatic polyamide; polyphenyl sulfide; fluororesin; polyvinyl chloride; polyvinylidene chloride; cellulose resin; and silicone resin. One type of the above resin may be used, or two or more types may be used.

[0119] Among the above-mentioned substrates, PET substrates are preferred from the viewpoint of being suitable for thin layering and being able to easily produce materials with high smoothness.

[0120] The above-mentioned substrate may include auxiliary layers. Examples of the above-mentioned auxiliary layers include a colored layer, a reflective layer, a primer layer, and an antistatic layer provided on the surface of the substrate.

[0121] The surface of the substrate may be subjected to surface treatments such as physical treatments like corona discharge treatment, plasma treatment, sandblasting, ozone exposure treatment, flame exposure treatment, high-voltage electric shock exposure treatment, and ionization radiation treatment; chemical treatments like chromic acid treatment; or surface treatments such as easy adhesion treatment with a coating agent (primer) in order to improve adhesion and retention with the adhesive layer. It is preferable that the surface treatment to improve adhesion is applied to the entire surface of the substrate.

[0122] The thickness of the above-mentioned substrate is not particularly limited, but is preferably 5 μm or more, and more preferably 10 μm or more. When the above-mentioned thickness is 5 μm or more, the strength is superior. The above-mentioned thickness is not particularly limited, but may be, for example, 100 μm or less, and may be 50 μm or less or 30 μm or less.

[0123] The adhesive sheet of the present invention may have a release liner attached to the surface (adhesive surface) of the adhesive layer until use. If the adhesive sheet is a double-sided adhesive sheet, each adhesive surface on both sides may be protected by two release liners, or it may be protected in a roll-like form (winding body) by a single release liner with both sides being release surfaces. The release liner is used as a protective material for the adhesive layer and is peeled off when it is attached to the object. Note that the release liner is not necessarily required.

[0124] The above-mentioned release liner can be conventional release paper or the like, and is not particularly limited, but examples include a substrate having a release treatment layer, a low-adhesion substrate made of a fluoropolymer, or a low-adhesion substrate made of a nonpolar polymer. Examples of the substrate having the release treatment layer include plastic films and paper surface-treated with release agents such as silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide. Examples of fluorine-based polymers in the low-adhesion substrate made of a fluoropolymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and chlorofluoroethylene-vinylidene fluoride copolymer. Examples of the above-mentioned nonpolar polymer include olefin resins (e.g., polyethylene, polypropylene, etc.). The release liner can be formed by known or conventional methods. The thickness of the release liner is also not particularly limited.

[0125] The adhesive sheet of the present invention is curable. Therefore, the adhesive sheet of the present invention, once bonded to an adherend, is a curable adhesive sheet. The adhesive layer and adhesive sheet of the present invention can be bonded to an adherend by bonding them together, curing the adhesive layer, and then adhering them to the adherend. Bonding to the adherend (adhesion by pressure) and curing the adhesive layer can be performed in either order. That is, curing operations such as light irradiation or heating may be performed on the adhesive layer after bonding to the adherend, or curing operations such as light irradiation or heating may be performed on the adhesive layer before bonding to the adherend, or a combination of these may be performed. For example, when two light-opaque adherends are bonded together using a double-sided adhesive sheet equipped with a photocurable adhesive layer, it becomes difficult to irradiate the adhesive layer with light after bonding. In such cases where it is difficult to perform curing operations on the adhesive layer after bonding to the adherend, the adhesive layer can be cured, and then it can be used by bonding it to the adherend shortly thereafter. Even in such cases, curing progresses gradually after bonding to the adherend, resulting in excellent adhesion to the adherend.

[0126] The curable adhesive composition, adhesive layer, and adhesive sheet of the present invention are preferably used for bonding electrical and electronic components, by being bonded to components provided in electrical and electronic equipment. The curable adhesive composition, adhesive layer, and adhesive sheet of the present invention are particularly preferably used for bonding components provided in electrical and electronic equipment to both adhesive surfaces of a double-sided adhesive sheet, that is, for fixing components together in electrical and electronic equipment. The curable adhesive composition, adhesive layer, and adhesive sheet of the present invention may be used for fixing the above components together or for temporary fixing. In one embodiment of the above electrical and electronic equipment, the curable adhesive sheet comprises a cured adhesive sheet, and the adhesive sheet fixes the components together on both adhesive surfaces.

[0127] Furthermore, "electrical and electronic equipment" refers to equipment that falls under either the category of electrical equipment or electronic equipment. Examples of such electrical and electronic equipment include image display devices such as liquid crystal displays, electroluminescent displays, and plasma displays, as well as portable electronic devices.

[0128] Examples of the above-mentioned portable electronic devices include mobile phones, smartphones, tablet computers, notebook computers, various wearable devices (for example, wristwear-type devices worn on the wrist like watches, modular-type devices attached to a part of the body with clips or straps, eyewear-type devices including glasses (monocular and binocular types, including head-mounted types), clothing-type devices attached to shirts, socks, hats, etc. as accessories, earwear-type devices attached to the ears like earphones, etc.), digital cameras, digital video cameras, audio equipment (portable music players, IC recorders, etc.), calculators (calculators, etc.), portable game consoles, electronic dictionaries, electronic organizers, e-books, in-car information systems, portable radios, portable televisions, portable printers, portable scanners, and portable modems. In this specification, "portable" means not merely being able to carry something, but having a level of portability that allows an individual (a typical adult) to carry it relatively easily. The above-mentioned adhesive sheet is used, for example, so that the adhesive layer adheres closely to the components of the above-mentioned portable electronic device.

[0129] The adhesive sheet of the present invention can also be used for bonding components (especially between components) in electrical and electronic equipment that is used in a folded manner, such as a flexible display (in particular a foldable display) (especially a foldable display). [Examples]

[0130] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples. Note that all amounts indicated refer to the amount (parts by mass) of each component described.

[0131] Example 1 (Preparation of acrylic polymers) In a reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet tube, reflux condenser, and dropping funnel, 95 parts of n-butyl acrylate (BA) and 5 parts of acrylic acid (AA) as monomer components, and 233 parts of ethyl acetate as polymerization solvent were charged, and the mixture was stirred for 2 hours while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, 0.2 parts of 2,2'-azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and solution polymerization was carried out at 60°C for 8 hours to obtain a solution of acrylic polymer A. The Mw of this acrylic polymer A is approximately 70 × 10⁻⁶ 4 That was the case.

[0132] (Preparation of adhesive composition) To the above acrylic polymer solution, 20 parts of epoxy resin (product name "Celoxide 2021P", manufactured by Daicel Corporation), 1 part of product name "CPI-310B" (manufactured by Sunapro Co., Ltd., a sulfonium salt type photoacid generator having aromatic sulfonium in the cation part) as a photoacid generator, and 3 parts of isocyanate crosslinking agent (product name "Takenate D-101E", manufactured by Mitsui Chemicals, Inc., tolylene diisocyanate) were added to 100 parts of acrylic polymer A contained in the solution, and the mixture was stirred to prepare an adhesive composition.

[0133] (Making adhesive sheets) The above adhesive composition was applied to the release surface of a 38 μm thick polyester release liner (product name "Diafoil MRF", manufactured by Mitsubishi Chemical Corporation) and dried at 100°C for 2 minutes to form a 15 μm thick adhesive layer. The release surface of a 25 μm thick polyester release liner (product name "Diafoil MRF", manufactured by Mitsubishi Chemical Corporation) was bonded to this adhesive layer. In this way, a 15 μm thick substrate-less double-sided adhesive sheet was obtained, with both sides protected by the two polyester release liners described above.

[0134] Examples 2-16, Comparative Examples 1-5 The adhesive compositions and double-sided adhesive sheets for each example were prepared in the same manner as in Example 1, except that the composition of the adhesive composition was changed as shown in Table 1 or Table 2. The amounts of each component in the table represent the solid content.

[0135] The components shown in Tables 1 and 2 are as follows: <Adhesive polymer> Acrylic polymer B: This is an acrylic polymer manufactured by the following method. In a reaction vessel equipped with a stirrer, thermometer, nitrogen gas inlet tube, reflux condenser, and dropping funnel, 95 parts of 2-ethylhexyl acrylate (2EHA) and 5 parts of acrylic acid (AA) as monomer components, and 233 parts of ethyl acetate as polymerization solvent were charged, and the mixture was stirred for 2 hours while introducing nitrogen gas. After removing oxygen from the polymerization system in this way, 0.2 parts of 2,2'-azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and solution polymerization was carried out at 60°C for 8 hours to obtain a solution of acrylic polymer B. The Mw of this acrylic polymer B is approximately 80 × 10⁻⁶ 4 That was the case. UV1700TL: Product name "UV1700TL", manufactured by Mitsubishi Chemical Corporation, urethane acrylic resin.

[0136] <Polyfunctional cyclic ether compounds> YX8000: Product name "YX8000", manufactured by Mitsubishi Chemical Corporation, hydrogenated epoxy resin OXT-221: Product name "Aron Oxetane OXT-221", manufactured by Toagosei Co., Ltd., 3-ethyl-3-{[(3-ethyloxetane-3-yl)methoxy]methyl}oxetane OXT-191: Product name "Aron Oxetane OXT-191", manufactured by Toagosei Co., Ltd., oxetanyl silicate <Acid Generator> CPI-310FG: Product name "CPI-310FG", manufactured by Sunapro Co., Ltd., a sulfonium salt type photoacid generator having aromatic sulfonium in the cation portion. <Photoradical initiator> Omnirad651: Product name "Omnirad651", manufactured by IGM RESINS. <Black pigment> A024 BLACK: Product name "A024 BLACK", manufactured by Tokushiki Co., Ltd., metal nitride. ATDN-101: Product name "ATDN-101", manufactured by Dainichi Seika Kogyo Co., Ltd., carbon black dispersion.

[0137] <Rating> The adhesive sheets obtained in the examples and comparative examples were evaluated as follows. The results are shown in the table.

[0138] (1) 180° peel-off adhesive strength Under a measurement environment of 23°C and 50% RH, the release liners on both sides were peeled off from the adhesive sheets prepared in the examples and comparative examples. A 50 μm thick polyethylene terephthalate (PET) film was attached to one adhesive surface of the adhesive sheet as a backing, and the sheet was cut to a size of 25 mm in width and 100 mm in length to prepare measurement samples. On the surface of the prepared measurement samples, a wavelength of 365 nm and an illuminance of 72 mW / cm² were applied. -2 , Total light intensity 3000 mJ / cm -2 Under these conditions, UV irradiation was performed, and the exposed surface of the measurement sample was pressed against the surface of a stainless steel plate (SUS304BA plate) by rolling a 2kg roller back and forth once in an environment of 23°C and 50%RH. After leaving it in the same environment for 30 minutes, the peel strength [N / 25mm] was measured using a universal tensile and compression testing machine in accordance with JIS Z 0237:2000, under conditions of a tensile speed of 300mm / min and a peel angle of 180 degrees.

[0139] (2) Shear bond strength The adhesive sheets prepared in the examples and comparative examples were cut to a size of 10 mm x 10 mm to prepare measurement samples. Under conditions of 23°C and 50% RH, the release liners on both sides were peeled off the measurement samples, and one adhesive side of the adhesive sheet was attached to the surface of a stainless steel plate (SUS304BA plate). A wavelength of 365 nm and an illuminance of 72 mW / cm² were used for measurement. -2 , Total light intensity 3000 mJ / cm -2Under these conditions, UV irradiation was performed, and another stainless steel plate was placed on top and pressed together by passing a 2kg roller back and forth once. After leaving it in the same environment for two days, the shear adhesive strength [MPa] was measured using a tensile testing machine under the conditions of a tensile speed of 10 mm / min and a peel angle of 0°. A universal tensile and compression testing machine (product name "TG-1kN", manufactured by Minebea Co., Ltd.) was used as the tensile testing machine.

[0140] [Table 1]

[0141] [Table 2]

[0142] As shown in Tables 1 and 2, the adhesive sheets of the examples were evaluated to have high 180° peel adhesion and shear adhesion to stainless steel plates, and high adhesion to the substrate after curing. On the other hand, when the content of the polyfunctional cyclic ether compound was high (Comparative Examples 1-3), the 180° peel adhesion and shear adhesion were low, and the adhesion to the substrate after curing was evaluated to be poor. Furthermore, when urethane acrylic resin was used instead of the polyfunctional cyclic ether compound to improve adhesion (Comparative Examples 4, 5), the 180° peel adhesion and shear adhesion were low, and the adhesion to the substrate after curing was evaluated to be poor.

[0143] The following describes variations of the invention relating to this disclosure. [Note 1] The material comprises an adhesive polymer, a polyfunctional cyclic ether compound having two or more cyclic ether groups in one molecule, and an acid generator. A curable adhesive composition in which the polyfunctional cyclic ether compound is contained in an amount of 10 to 100 parts by mass per 100 parts by mass of the total amount of the adhesive polymer. [Note 2] The adhesive polymer is the curable adhesive composition according to Note 1, comprising an acrylic polymer. [Note 3] The curable adhesive composition according to Note 2, wherein the acrylic polymer contains 0.5 to 10% by mass of constituent units derived from carboxyl group-containing monomers and / or acid anhydride monomers. [Note 4] The curable adhesive composition according to any one of Notes 1 to 3, wherein the cyclic ether group in the polyfunctional cyclic ether compound comprises an epoxy group and / or an oxetanyl group. [Note 5] The curable adhesive composition according to any one of Notes 1 to 4, wherein the acid generator comprises a photoacid generator whose cation portion is aromatic sulfonium. [Note 6] A curable adhesive composition according to any one of Notes 1 to 5, for fixing components together in electrical and electronic equipment. [Note 7] A curable adhesive sheet comprising an adhesive layer made of the curable adhesive composition described in any one of Notes 1 to 6. [Note 8] An electrical and electronic device comprising a curable adhesive sheet as described in Note 7, wherein the adhesive sheet fixes components together on both adhesive surfaces. [Explanation of symbols]

[0144] 1 Adhesive sheet 2. Adhesive layer 3,4 Peel-off liner

Claims

1. The material comprises an adhesive polymer, a polyfunctional cyclic ether compound having two or more cyclic ether groups in one molecule, and an acid generator. A curable adhesive composition in which the polyfunctional cyclic ether compound is contained in an amount of 10 to 100 parts by mass per 100 parts by mass of the total amount of the adhesive polymer.

2. The curable adhesive composition according to claim 1, wherein the adhesive polymer comprises an acrylic polymer.

3. The curable adhesive composition according to claim 2, wherein the acrylic polymer contains 0.5 to 10% by mass of constituent units derived from carboxyl group-containing monomers and / or acid anhydride monomers.

4. The curable adhesive composition according to claim 1 or 2, wherein the cyclic ether group in the polyfunctional cyclic ether compound comprises an epoxy group and / or an oxetanyl group.

5. The curable adhesive composition according to claim 1 or 2, wherein the acid generator comprises a photoacid generator whose cation portion is aromatic sulfonium.

6. A curable adhesive composition according to claim 1 or 2, for fixing components together in electrical and electronic equipment.

7. A curable adhesive sheet comprising an adhesive layer made of the curable adhesive composition according to claim 1 or 2.

8. Electrical and electronic equipment comprising a curable adhesive sheet according to claim 7, wherein the adhesive sheet fixes members together on both adhesive surfaces.

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