Photocurable adhesive composition, adhesive, member with adhesive, method for producing adhesive, cured body, member, and method for producing cured body

Abstract

The provided photocurable adhesive composition comprises a monomer component M, a photoinitiator, and a colorant. The organic solvent content in the photocurable adhesive composition is less than 1 wt%. The colorant may be a black colorant. An adhesive formed from the photocurable adhesive composition may have a total light transmittance of less than 5%, and may have a refractive index of 1.50 or greater. This photocurable adhesive composition is suitable for suppressing curing failure even while containing a colorant.

Description

Photocurable adhesive composition, adhesive, adhesive-coated component, method for manufacturing the adhesive, cured body, component, and method for manufacturing the cured body

[0001] The present invention relates to a photocurable adhesive composition, an adhesive, an adhesive-coated member, a method for producing an adhesive, a cured body, a member, and a method for producing a cured body.

[0002] Generally, adhesives exhibit a soft solid (viscoelastic) state at temperatures around room temperature and readily adhere to a substrate under pressure. Taking advantage of these properties, adhesives are widely used for various applications and purposes, such as joining, fixing, and protecting components in electronic equipment.

[0003] Examples of electronic devices include image display devices such as liquid crystal displays and electroluminescent (EL) displays. For example, sheets made of adhesive (adhesive sheets) are used as optical components in image display devices. Adhesives, typically those with light-shielding properties, are sometimes used to prevent light leakage and reflection. Colored adhesives are also sometimes used to improve the design and function of products. Patent Document 1 discloses an example of an adhesive sheet.

[0004] Adhesives can be formed from adhesive compositions. Patent Document 1 discloses a thermosetting adhesive composition containing a thermal initiator as a polymerization initiator. In addition to thermosetting adhesive compositions, photocurable adhesive compositions are also known. Photocurable adhesive compositions typically contain a photoinitiator as a polymerization initiator.

[0005] International Publication No. 2021 / 153500

[0006] According to the inventors' studies, photocurable adhesive compositions (photocurable adhesive compositions) containing colorants tend to be prone to curing defects.

[0007] The present invention aims to provide a technology suitable for suppressing curing defects in photocurable adhesive compositions containing colorants.

[0008] [1] A photocurable adhesive composition according to an embodiment of the present invention comprises a monomer component M, a photoinitiator, and a colorant, and the content of an organic solvent is less than 1% by weight. [2] In the photocurable adhesive composition described in [1] above, the colorant may be a black colorant. [3] In the photocurable adhesive composition described in [1] or [2] above, the colorant may contain a carbon compound. [4] In the photocurable adhesive composition described in any of [1] to [3] above, the content of (meth)acrylic monomer in the monomer component M may be 50% by weight or more. [5] In the photocurable adhesive composition described in any of [1] to [4] above, the monomer component M may contain monomer a having a double bond-containing ring. [6] In the photocurable adhesive composition described in [5] above, the double bond-containing ring may be an aromatic ring. [7] In the photocurable adhesive composition described in [5] or [6] above, monomer a may have two or more of the double bond-containing rings in its side chain. [8] In the photocurable adhesive composition described in [7] above, monomer a may have a side chain structure in which a first double bond-containing ring and a second double bond-containing ring, which are included in the two or more double bond-containing rings, are linked via a linking group. [9] In the photocurable adhesive composition described in any of [5] to [8] above, monomer a may be phenoxybenzyl acrylate.

[10] The photocurable adhesive composition described in any of [1] to [9] above may contain the photoinitiator having the chemical structure shown in the following formula (1) in its molecule. However, the "*" in formula (1) indicates a bond site with another atom.

[11] In the photocurable adhesive composition described in any of [1] to

[10] above, the content of the photoinitiator in the photocurable adhesive composition may be 0.01 to 10 parts by weight per 100 parts by weight of the monomer component M.

[12] The adhesive according to the embodiment of the present invention is an adhesive formed from the photocurable adhesive composition described in any of [1] to

[11] above.

[13] In the adhesive described in

[12] above, the polymerization rate of the monomer component M may be 98.0% or more.

[14] The adhesive described in

[12] or

[13] above is CIE1976(L) as defined in JIS Z8781-4:2013. * , a * , b * ) L in the color space * It may be displayed as such and have a brightness of 60.0 or less.

[15] The adhesive described in

[14] above is a in the color space * The absolute value of has a chromaticity of 10.0 or less, and the b of the color space *

[16] The adhesive described in any of

[12] to

[15] above may have a chromaticity of 10.0 or less when expressed by its absolute value.

[17] The adhesive described in any of

[12] to

[16] above may have a refractive index of 1.50 or more.

[18] The adhesive described in any of

[12] to

[17] above may have a total light transmittance of less than 5%.

[19] An adhesive-coated member according to an embodiment of the present invention comprises the adhesive and member described in any of

[12] to

[17] above.

[18] The adhesive-coated member described in

[18] above may be an adhesive-coated optical member.

[20] A method for producing an adhesive according to an embodiment of the present invention includes curing the photocurable adhesive composition described in any of [1] to

[11] above by irradiating it with light.

[21] A cured body according to an embodiment of the present invention is formed from the adhesive described in any of

[12] to

[17] above.

[22] A member according to an embodiment of the present invention comprises the cured body described in

[21] above.

[23] The member described in

[22] above may be an optical member.

[24] A method for producing a cured body according to an embodiment of the present invention includes further curing the adhesive described in any of

[12] to

[17] in a high-temperature environment.

[0009] According to embodiments of the present invention, a technology suitable for suppressing curing defects can be provided for photocurable adhesive compositions containing a coloring agent.

[0010] This is a schematic diagram illustrating an example of a method for forming an adhesive according to one embodiment of the present invention. This is a schematic diagram illustrating an example of a method for forming an adhesive according to one embodiment of the present invention. This is a schematic diagram illustrating an example of a method for forming an adhesive according to one embodiment of the present invention.

[0011] [Regarding Terminology] In this specification, where the term "weight" appears, it may be interpreted as "mass," which is the commonly used SI unit for weight. The reverse is also true.

[0012] In this specification, the expression "(meth)acrylic" means "acrylic and / or methacrylic," the expression "(meth)acrylate" means "acrylate and / or methacrylate," the expression "(meth)allyl" means "allyl and / or methallyl," and the expression "(meth)acrolein" means "acrolein and / or metacrolein."

[0013] In this specification, "100 parts by weight of monomer component M" as a standard for the content of various components in the adhesive composition means 100 parts by weight of the total amount of monomer component M that has not been partially polymerized and monomer component M that has been used to form partially polymerized products contained in the adhesive composition.

[0014] ≪≪1. Photocurable Adhesive Composition≫≫ A photocurable adhesive composition according to an embodiment of the present invention (hereinafter referred to as "adhesive composition A") comprises a monomer component M, a photoinitiator, and a colorant. The photocurable adhesive composition is a composition capable of forming an adhesive by photocuring by irradiation with light, typically ultraviolet light. The colorant contained in the adhesive composition may inhibit the photocuring of the adhesive composition by absorbing the irradiated light. In contrast, adhesive composition A contains less than 1% by weight of organic solvent. According to the inventors' studies, it is considered that limiting the content of organic solvent in adhesive composition A to less than 1% by weight contributes to suppressing curing defects. The suppression of curing defects may be based on the fact that by limiting the above content to less than 1% by weight, the concentration of monomers present around the colorant increases, thereby suppressing the deactivation of radicals by functional groups that may be present on the surface of the colorant (the reaction of monomers present around the colorant proceeds before radicals are deactivated).

[0015] The content of the organic solvent in adhesive composition A may be 0.9% by weight or less, 0.8% by weight or less, 0.7% by weight or less, 0.6% by weight or less, 0.5% by weight or less, 0.4% by weight or less, 0.3% by weight or less, 0.2% by weight or less, and even 0.1% by weight or less. Adhesive composition A may not contain any organic solvent at all. In this specification, "substantially contained" means that the content is less than 0.1% by weight, preferably 0.05% by weight or less, more preferably 0.01% by weight or less, even more preferably less than 0.01% by weight, and particularly preferably less than 0.001% by weight.

[0016] ≪1-1. Monomer Component M≫ Monomer component M contains one or more monomers. The monomers contained in monomer component M may be (meth)acrylic monomers. The content of (meth)acrylic monomers in monomer component M may be 50% by weight or more. In this case, it is possible to form a (meth)acrylic adhesive. The above content may be 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, 95% by weight or more, 97% by weight or more, 98% by weight or more, 99% by weight or more, and even 100% by weight or more.

[0017] In this specification, (meth)acrylic monomer means a monomer having at least one (meth)acryloyl group in one molecule. Preferably, the (meth)acrylic monomer is a monomer having one (meth)acryloyl group (in other words, a monofunctional (meth)acrylic monomer).

[0018] In this specification, the amount of monomer component M used as a standard for the content of each monomer in monomer component M is the sum of the amount of monomer component M that has not been partially polymerized and the amount of monomer component M that was used to form the partially polymerized product contained in the adhesive composition. Furthermore, the amount of each monomer used to calculate the above content is the sum of the amount of each monomer that has not been partially polymerized and the amount of each monomer that was used to form the partially polymerized product contained in the adhesive composition.

[0019] <1-1-a. (Meth)acrylate alkyl esters> An example of monomers that may be included in monomer component M is an alkyl (meth)acrylate having an alkyl group with 1 to 20 carbon atoms in its side chain. The number of carbon atoms in the alkyl group may be 7 or less, 6 or less, 5 or less, or even 4 or less. The alkyl group may be linear or branched. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. These are lylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate (lauryl (meth)acrylate), n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, and octadecyl (meth)acrylate. The alkyl (meth)acrylate may be at least one selected from the group consisting of 2-ethylhexyl (meth)acrylate and n-butyl (meth)acrylate.

[0020] The content of alkyl (meth)acrylate in monomer component M is, for example, 0.1% by weight or more, and may be 0.3% by weight or more, 0.5% by weight or more, 0.8% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 8% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 88% by weight or more, 90% by weight or more, 93% by weight or more, 95% by weight or more, 98% by weight or more, and even 99% by weight or more. The upper limit of the above content is, for example, 100% by weight or less, and may be 99% by weight or less, 98% by weight or less, 95% by weight or less, 93% by weight or less, 90% by weight or less, 88% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, 50% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 8% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, and even 0.1% by weight or less. The monomer component M does not have to substantially contain alkyl (meth)acrylate.

[0021] In this specification, with respect to a component whose content in adhesive composition A is specified by a range of parts by weight relative to 100 parts by weight of monomer component M, "substantially absent" means that the content is less than 0.1 parts by weight, preferably 0.05 parts by weight or less, more preferably 0.01 parts by weight or less, even more preferably less than 0.01 parts by weight, and particularly preferably less than 0.001 parts by weight.

[0022] The monomer component M may contain one or more alkyl (meth)acrylate esters. The monomer component M may contain at least one alkyl (meth)acrylate ester selected from the group consisting of the examples described above.

[0023] <1-1-b. Monomer a> Monomer component M may include monomer a having a double bond-containing ring. Including monomer a is suitable for improving the refractive index of the adhesive formed from adhesive composition A, for example. In this specification, a double bond-containing ring means a ring in which at least one of the bonds constituting the ring is a double bond. Examples of double bonds are carbon-carbon double bonds, carbon-heteroatom double bonds, and heteroatom-heteroatom double bonds. Examples of heteroatoms are nitrogen atoms, sulfur atoms, and oxygen atoms.

[0024] The number of double bonds in the double bond-containing ring is not particularly limited and may be, for example, 1 to 10, or 2 to 5. When the double bond-containing ring contains two or more double bonds, these double bonds may be conjugated or unconjugated. The double bond-containing ring is preferably an aromatic ring.

[0025] The double bond-containing ring may be a carboelectric ring. Examples of carboelectric rings include a benzene ring (which may be a benzene ring that constitutes part of a biphenyl or fluorene structure), a naphthalene ring, an indene ring, an azulene ring, an anthracene ring, and a phenanthrene ring. The double bond-containing ring may also be a heterocycle. Examples of heterocycles include a pyridine ring, a pyrimidine ring, a pyridazine ring, a pyrazine ring, a triazine ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a triazole ring, an oxazole ring, an isoxazole ring, a thiazole ring, and a thiophene ring. Examples of heteroatoms that can be included in a heterocycle as ring constituent atoms are at least one selected from the group consisting of nitrogen, sulfur, and oxygen atoms. The heteroatom may be either a nitrogen atom or a sulfur atom, or both. The double bond-containing ring may also be a fused ring. An example of monomer a is a structure in which one or more carboelectric rings and one or more heterocycles are fused, such as the dinaphthothiophene structure.

[0026] A double bond-containing ring may have one or more substituents (excluding ethylenically unsaturated groups, as described later) on its ring atoms, or it may not have substituents. Examples of substituents include alkyl groups, alkoxy groups, aryloxy groups, hydroxyl groups, halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, etc.), hydroxyalkyl groups, hydroxyalkyloxy groups, and glycidyloxy groups. However, substituents are not limited to the above examples. Substituents may contain carbon atoms, in which case the number of carbon atoms in the substituent may be, for example, 1 to 4, 1 to 3, or even 1 to 2. An example of a double bond-containing ring is one which has no substituents on its ring atoms. Another example of a double bond-containing ring is one which has one or more substituents selected from the group consisting of alkyl groups, alkoxy groups, and halogen atoms (e.g., bromine atoms) on its ring atoms.

[0027] In monomer a, the number of double-bond-containing rings in one molecule is, for example, 1, but may be 2 or more. There is no particular upper limit to the number of double-bond-containing rings, for example, 16 or less. The upper limit may be 12 or less, 8 or less, 6 or less, 5 or less, 4 or less, 3 or less, or even 2 or less.

[0028] In monomer a, the double bond-containing ring is preferably located in the side chain. In other words, monomer a may have a double bond-containing ring in its side chain. It is preferable that monomer a has at least one double bond-containing ring and at least one ethylenically unsaturated group in one molecule. As monomer a, a compound in which the number of ethylenically unsaturated groups in one molecule is one (in other words, a monofunctional monomer) is preferably used.

[0029] Examples of ethylenically unsaturated groups include (meth)acryloyl, vinyl, and (meth)allyl groups. From the viewpoint of polymerization reactivity, the (meth)acryloyl group is preferred, and from the viewpoint of flexibility and tackiness, the acryloyl group is more preferred. In other words, monomer a preferably contains a (meth)acrylic monomer having a double bond-containing ring, and more preferably contains an acrylic monomer having a double bond-containing ring. An example of a (meth)acrylic monomer having a double bond-containing ring is an aromatic ring-containing (meth)acrylate. Specific examples of aromatic ring-containing (meth)acrylates will be described later.

[0030] The double bond-containing ring and the ethylenically unsaturated group may be directly bonded or bonded via a linking group. Examples of linking groups include one or more selected from the group consisting of alkylene groups, oxyalkylene groups, poly(oxyalkylene) groups, phenyl groups, alkylphenyl groups, alkoxyphenyl groups, groups in which one or more hydrogen atoms are substituted with hydroxyl groups (e.g., hydroxyalkylene groups), oxy groups (-O-), and thiooxy groups (-S-). In one example of monomer a, the double bond-containing ring and the ethylenically unsaturated group are directly bonded. In another example of monomer a, the double bond-containing ring and the ethylenically unsaturated group are bonded via a linking group selected from the group consisting of alkylene groups, oxyalkylene groups, and poly(oxyalkylene) groups. The number of carbon atoms in the alkylene and oxyalkylene groups that may be included in the linking group is, for example, 1 to 4, and may also be 1 to 3, or even 1 to 2. The number of repeating oxyalkylene units in the poly(oxyalkylene) group that may be included in the linking group is, for example, 1 to 8, and may be 1 to 6, 1 to 4, 1 to 3, 2 to 3, or even 1 to 2, or 2, or 1.

[0031] Specific examples of monomer a are aromatic ring-containing (meth)acrylates and aromatic ring-containing vinyl compounds. The aromatic ring-containing (meth)acrylates and aromatic ring-containing vinyl compounds may be one or more of each, in combination.

[0032] Monomer a may have two or more double bond-containing rings in the side chain. Further, monomer a may have a structure in the side chain in which a first double bond-containing ring and a second double bond-containing ring contained in two or more double bond-containing rings are bonded via a linking group.

[0033] Monomer a may contain two or more aromatic rings (preferably carbocyclic rings) in one molecule. A monomer having two or more aromatic rings and at least one ethylenically unsaturated group in one molecule (a monomer containing a plurality of aromatic rings) can particularly contribute to increasing the refractive index of the adhesive.

[0034] Examples of the monomer containing a plurality of aromatic rings include a monomer having a structure in which two or more non-condensed aromatic rings are bonded via a linking group, a monomer having a structure in which two or more non-condensed aromatic rings are directly bonded, a monomer having a condensed ring, a monomer having a fluorene structure, a monomer having a dinaphthothiophene structure, and a monomer having a dibenzothiophene structure. Among them, a monomer having a structure in which two or more non-condensed aromatic rings are bonded via a linking group (for example, phenoxybenzyl (meth)acrylate described later) is preferably used.

[0035] The linking group for bonding two or more double bond-containing rings, for example, an aromatic ring, may contain atoms such as P, Ge, Te, Se, N, S, Si, etc., and these atoms may be bonded to an oxygen atom. However, the linking group may not contain the above atoms. Examples of the linking group include an oxy group (—O—), a thiooxy group (—S—), an oxyalkylene group (for example, —O—(CH2) n —; n is 1 to 3, preferably 1), a thiooxyalkylene group (for example, —S—(CH2) n —; n is 1 to 3, preferably 1), a linear alkylene group (—(CH2) n-; n is 1 to 6, preferably 1 to 3), and the alkylene group in the oxyalkylene group, the thiooxyalkylene group, and the linear alkylene group is partially halogenated or fully halogenated. The linking group may include one or more selected from the group consisting of an oxy group, a thiooxy group, an oxyalkylene group, and a linear alkylene group. Specific examples of monomers having a structure in which two or more non-condensed aromatic rings are linked via a linking group are phenoxybenzyl(meth)acrylate, thiophenoxybenzyl(meth)acrylate, and benzylbenzyl(meth)acrylate.

[0036] Examples of monomers having a structure in which two or more non-condensed aromatic rings are directly bonded include biphenyl structure-containing (meth)acrylates, triphenyl structure-containing (meth)acrylates, and vinyl group-containing biphenyls. Specific examples include o-phenylphenol (meth)acrylate, biphenyl (meth)acrylate, and biphenylmethyl (meth)acrylate.

[0037] Examples of monomers having condensed rings include naphthalene ring-containing (meth)acrylates, anthracene ring-containing (meth)acrylates, vinyl group-containing naphthalene, and vinyl group-containing anthracene. Specific examples include 1-naphthylmethyl (meth)acrylate (also known as 1-naphthalenemethyl (meth)acrylate), hydroxyethylated β-naphthol acrylate, 2-naphthoethyl (meth)acrylate, 2-naphthoxyethyl acrylate, and 2-(4-methoxy-1-naphthoxy)ethyl (meth)acrylate.

[0038] Examples of monomers having a fluorene structure are 9,9-bis(4-hydroxyphenyl)fluorene(meth)acrylate and 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene(meth)acrylate. Note that monomers having a fluorene structure are included in the concept of monomers having a structure in which two or more non-condensed aromatic rings are directly bonded, as they have a structure in which two benzene rings are directly bonded.

[0039] Examples of monomers having a dinaphthothiophene structure include (meth)acryloyl group-containing dinaphthothiophene, vinyl group-containing dinaphthothiophene, and (meth)allyl group-containing dinaphthothiophene. Specific examples include (meth)acryloyloxymethyldinaphthothiophene (for example, compounds having a structure in which a CH2CH(R1)C(O)OCH2 group is bonded to the 5th or 6th position of the dinaphthothiophene ring; R1 is a hydrogen atom or a methyl group), (meth)acryloyloxyethyldinaphthothiophene (for example, compounds having a structure in which a CH2CH(R1)C(O)OCH(CH3) group or a CH2CH(R1)C(O)OCH2CH2 group is bonded to the 5th or 6th position of the dinaphthothiophene ring; R1 is a hydrogen atom or a methyl group), vinyldinaphthothiophene (for example, compounds having a structure in which a vinyl group is bonded to the 5th or 6th position of the naphthothiophene ring), and (meth)allyloxydinaphthothiophene. Furthermore, monomers having a dinaphthothiophene structure are included in the concept of monomers having a fused ring, because they also have a naphthalene structure and a structure in which a thiophene ring and two naphthalene structures are fused together.

[0040] Examples of monomers containing a dibenzothiophene structure include (meth)acryloyl group-containing dibenzothiophene and vinyl group-containing dibenzothiophene. Note that monomers containing a dibenzothiophene structure are included in the concept of monomers containing a fused ring, as they have a structure in which a thiophene ring and two benzene rings are fused. Neither the dinaphthothiophene structure nor the dibenzothiophene structure corresponds to a structure in which two or more non-fused aromatic rings are directly bonded.

[0041] Monomer a may be a monomer having one aromatic ring (preferably a carbon ring) and at least one ethylenically unsaturated group in one molecule (a monomer containing one aromatic ring).

[0042] Examples of monomers containing a single aromatic ring include carbon aromatic ring-containing (meth)acrylates such as benzyl (meth)acrylate, methoxybenzyl (meth)acrylate, phenyl (meth)acrylate, ethoxylated phenol (meth)acrylate, phenoxypropyl (meth)acrylate, phenoxybutyl (meth)acrylate, cresyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, chlorobenzyl (meth)acrylate, etc.; 2-(4,6-dibromo-2-s-butylphenoxy)ethyl (meth)acrylate, 2-(4,6-dibromo-2-isopropylphenoxy)ethyl (meth)acrylate, 6-(4 These include bromine-substituted aromatic ring-containing (meth)acrylates such as 6-dibromo-2-s-butylphenoxy)hexyl (meth)acrylate, 6-(4,6-dibromo-2-isopropylphenoxy)hexyl (meth)acrylate, 2,6-dibromo-4-nonylphenyl acrylate, and 2,6-dibromo-4-dodecylphenyl acrylate; carbon aromatic ring-containing vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, and tert-butylstyrene; and compounds having vinyl substituents on heteroaromatic rings such as N-vinylpyridine, N-vinylpyrimidine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, and N-vinyloxazole.

[0043] Monomer a may have a structure in which an oxyethylene chain is interposed between the ethylenically unsaturated group and the double bond-containing ring in the various monomers a described above. Monomers having this structure can be understood as ethoxylated products of the original monomer. The number of repeating oxyethylene units (-CH2CH2O-) in the oxyethylene chain is, for example, 1 to 8, and may be 1 to 6, 1 to 4, 1 to 3, or even 1 to 2, or even 1. Examples of monomer a that are ethoxylated products are ethoxylated o-phenylphenol (meth)acrylate, ethoxylated nonylphenol (meth)acrylate, ethoxylated cresol (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxydiethylene glycol (meth)acrylate.

[0044] Monomer a may include high refractive index monomers. In this specification, high refractive index monomers mean monomers having refractive indices of 1.51 or higher, 1.52 or higher, 1.53 or higher, 1.54 or higher, 1.55 or higher, 1.56 or higher, 1.57 or higher, 1.58 or higher, 1.59 or higher, 1.60 or higher, 1.61 or higher, 1.62 or higher, 1.63 or higher, 1.64 or higher, 1.65 or higher, 1.66 or higher, 1.67 or higher, 1.68 or higher, and even 1.69 or higher. The upper limit of the refractive index of the high refractive index monomer is not particularly limited, and may be, for example, 3.00 or lower, but may also be 2.50 or lower, 2.00 or lower, 1.90 or lower, 1.80 or lower, and even 1.70 or lower. High refractive index monomers can be used individually or in combination of two or more.

[0045] The refractive index of a monomer can be measured using an Abbe refractometer under the conditions of a measurement wavelength of 589 nm and a measurement temperature of 25°C. An Abbe refractometer of model DR-M4 manufactured by ATAGO or an equivalent (e.g., model DR-M2) may be used. If the monomer manufacturer provides a nominal refractive index value at 25°C, that nominal value can be used as the refractive index.

[0046] Examples of high refractive index monomers include phenoxybenzyl acrylate (refractive index 1.566), 1-naphthylmethyl acrylate (refractive index 1.595), ethoxylated o-phenylphenol acrylate (refractive index 1.578 when the number of oxyethylene units repeating is 1), benzyl acrylate (refractive index 1.519), phenoxyethyl acrylate (refractive index 1.517), phenoxydiethylene glycol acrylate (refractive index 1.510), 6-acryloyloxymethyldinaphthothiophene (refractive index 1.75), 6-methacryloyloxymethyldinaphthothiophene (refractive index 1.726), 5-acryloyloxyethyldinaphthothiophene (refractive index 1.786), 6-acryloyloxyethyldinaphthothiophene (refractive index 1.722), 6-vinyldinaphthothiophene (refractive index 1.802), and 5-vinyldinaphthothiophene (refractive index 1.793). However, the high refractive index monomer is not limited to the above examples. Preferably, monomer a includes phenoxybenzyl acrylate as the high refractive index monomer.

[0047] Monomer a may be phenoxybenzyl acrylate.

[0048] The content of monomer a in monomer component M is, for example, 0.1% by weight or more, and may be 0.3% by weight or more, 0.5% by weight or more, 0.8% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 8% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 88% by weight or more, 90% by weight or more, 93% by weight or more, 95% by weight or more, 98% by weight or more, and even 99% by weight or more. The upper limit of the above content is, for example, 100% by weight or less, and may be 99% by weight or less, 98% by weight or less, 95% by weight or less, 93% by weight or less, 90% by weight or less, 88% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, 50% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 8% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, and even 0.1% by weight or less. The monomer component M does not have to substantially contain monomer a.

[0049] The monomer component M may contain one or more monomers a. The monomer component M may contain at least one monomer a selected from the group consisting of the examples described above.

[0050] <1-1-c. Other Monomers> Monomer component M may include other monomers other than those described above. An example of other monomers is a hydroxyl group-containing monomer. A hydroxyl group-containing monomer has at least one hydroxyl group and at least one ethylenically unsaturated group in one molecule. Monomer component M may contain one or more hydroxyl group-containing monomers. Monomer component M may contain at least one hydroxyl group-containing monomer selected from the group consisting of the examples below.

[0051] Examples of ethylenically unsaturated groups are the same as those described above in the explanation of monomer a. The hydroxyl group-containing monomer may also be a (meth)acrylic monomer.

[0052] Examples of hydroxyl group-containing monomers are 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl acrylate. The hydroxyl group-containing monomer is preferably 4-hydroxybutyl (meth)acrylate.

[0053] The content of hydroxyl group-containing monomers in monomer component M is, for example, 25% by weight or less, and may be 20% by weight or less, 15% by weight or less, 12% by weight or less, 10% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, and even 0.1% by weight or less. The lower limit of the content is, for example, 0.1% by weight or more, and may be 0.3% by weight or more, 0.5% by weight or more, and even 1% by weight or more. Monomer component M does not have to substantially contain hydroxyl group-containing monomers.

[0054] Another example of other monomers is an aliphatic ring-containing monomer. An aliphatic ring-containing monomer has at least one aliphatic ring and at least one ethylenically unsaturated group in one molecule. Monomer component M may contain one or more aliphatic ring-containing monomers. Monomer component M may contain at least one aliphatic ring-containing monomer selected from the group consisting of the examples below.

[0055] Examples of ethylenically unsaturated groups are the same as those described above in the explanation of monomer a. The aliphatic ring-containing monomer may also be a (meth)acrylic monomer.

[0056] Examples of aliphatic ring-containing monomers include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, cyclooctyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, and adamantyl (meth)acrylate.

[0057] The content of aliphatic ring-containing monomers in monomer component M is, for example, 25% by weight or less, and may be 20% by weight or less, 15% by weight or less, 12% by weight or less, 10% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, and even 0.1% by weight or less. The lower limit of the content is, for example, 0.1% by weight or more, and may be 0.3% by weight or more, 0.5% by weight or more, and even 1% by weight or more. Monomer component M does not have to substantially contain aliphatic ring-containing monomers.

[0058] Another example of other monomers is a carboxyl group-containing monomer. A carboxyl group-containing monomer that monomer component M may contain has at least one carboxyl group and at least one ethylenically unsaturated group in one molecule. Monomer component M may contain one or more carboxyl group-containing monomers. Monomer component M may contain at least one carboxyl group-containing monomer selected from the group consisting of the examples below.

[0059] Examples of ethylenically unsaturated groups are the same as those described above in the explanation of monomer a. The carboxyl group-containing monomer may also be a (meth)acrylic monomer.

[0060] Examples of monomers containing a carboxyl group include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

[0061] The content of carboxyl group-containing monomers in monomer component M is, for example, 10% by weight or less, and may be 7% by weight or less, 5% by weight or less, 3% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, and even 0.1% by weight or less. The lower limit of the content is, for example, 0.1% by weight or more, and may be 0.3% by weight or more, 0.5% by weight or more, and even 1% by weight or more. Monomer component M does not have to substantially contain carboxyl group-containing monomers.

[0062] Another example of other monomers is ether group-containing monomers (excluding cyclic ether group-containing monomers, as described later). The ether group-containing monomers that monomer component M may contain have at least one ether group and at least one ethylenically unsaturated group in one molecule. Monomer component M may contain one or more ether group-containing monomers. Monomer component M may contain at least one ether group-containing monomer selected from the group consisting of the examples below.

[0063] Examples of ethylenically unsaturated groups are the same as those described above in the explanation of monomer a. The ether group-containing monomer may also be a (meth)acrylic monomer.

[0064] The ether group in an ether group-containing monomer is usually contained in the portion that becomes the side chain after polymerization. The side chain may be linear or branched. The ether group-containing monomer may also contain oxyalkylene groups, and the number of oxyalkylene groups in one molecule may be, for example, 1 to 30, 1 to 12, or even 1 to 5.

[0065] Examples of oxyalkylene groups include oxymethylene, oxyethylene, and oxypropylene groups. Ether group-containing monomers preferably have an oxyethylene group. An ether group-containing monomer having an oxyethylene group can be represented, for example, by the following formula (2).

[0066] R in equation (2) 1 R is a hydrogen atom or a methyl group. 2 The hydrocarbon group is a hydrocarbon group. In a preferred example, the hydrocarbon group is an alkyl group. The alkyl group may be linear or branched. Examples of alkyl groups are the methyl group and the ethyl group. In another example, the hydrocarbon group contains a carbon ring. Examples of carbon rings are the same as those described above in the description of double bond-containing rings. An example of a hydrocarbon group containing a carbon ring is the phenyl group.

[0067] In equation (2), n is an integer from 1 to 30, preferably an integer from 1 to 12, and may also be an integer from 1 to 5.

[0068] Examples of ether group-containing monomers include 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, and methoxydipropylene glycol (meth)acrylate.

[0069] The content of ether group-containing monomers in monomer component M is, for example, 25% by weight or less, and may be 20% by weight or less, 15% by weight or less, 12% by weight or less, 10% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, and even 0.1% by weight or less. The lower limit of the content is, for example, 0.1% by weight or more, and may be 0.3% by weight or more, 0.5% by weight or more, and even 1% by weight or more. Monomer component M does not have to substantially contain ether group-containing monomers.

[0070] Another example of a monomer is a cyclic ether group-containing monomer. When used in combination with a crosslinking agent, cyclic ether group-containing monomers may be suitable for promoting the formation of the cured product described later. The cyclic ether group-containing monomer that monomer component M may contain preferably has at least one cyclic ether group and at least one ethylenically unsaturated group in one molecule. As the cyclic ether group-containing monomer, a compound having one ethylenically unsaturated group in one molecule (in other words, a monofunctional monomer) is preferably used. Monomer component M may contain one or more cyclic ether group-containing monomers. Monomer component M may contain at least one cyclic ether group-containing monomer selected from the group consisting of the following examples.

[0071] Examples of ethylenically unsaturated groups are the same as those described above in the explanation of monomer a. The cyclic ether group-containing monomer may also be a (meth)acrylic monomer.

[0072] The cyclic ether group in a cyclic ether group-containing monomer is usually contained in the portion that becomes the side chain after polymerization. The side chain may be linear or branched.

[0073] A cyclic ether group is a functional group that contains a ring having an ether bond. Examples of cyclic ether groups are epoxy groups and oxetane groups. A cyclic ether group may be at least one selected from the group consisting of epoxy groups and oxetane groups, or it may be an epoxy group.

[0074] The number of cyclic ether groups in a single molecule of a cyclic ether group-containing monomer is preferably one, but may be two or more. There is no particular upper limit to the number of cyclic ether groups; for example, it may be five or less, four or less, three or less, or even two or less. If two or more cyclic ether groups are included, the cyclic ether groups may all be of the same type, or different types of cyclic ether groups may be mixed together.

[0075] It is preferable that the cyclic ether group and the ethylenically unsaturated group are linked via a linking group. Examples of linking groups for monomer a include those described above, with alkylene groups and oxyalkylene groups being preferred. The number of carbon atoms in the linking group (specifically alkylene groups and oxyalkylene groups) is, for example, 1 or more, and may be 2 or more, 3 or more, or even 4 or more. The upper limit of the number of carbon atoms is, for example, 10 or less, and may be 8 or less, or even 5 or less.

[0076] Examples of cyclic ether group-containing monomers include epoxy group-containing (meth)acrylates and oxetane group-containing (meth)acrylates. Examples of epoxy group-containing (meth)acrylates include glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate glycidyl ether, with 4-hydroxybutyl acrylate glycidyl ether being preferred. Examples of oxetane group-containing (meth)acrylates include (3-oxetane-3-yl)methyl (meth)acrylate, (3-methyloxetane-3-yl)methyl (meth)acrylate, (3-ethyloxetane-3-yl)methyl (meth)acrylate, (3-butyloxetane-3-yl)methyl (meth)acrylate, and (3-hexyloxetane-3-yl)methyl (meth)acrylate.

[0077] The content of cyclic ether group-containing monomers in monomer component M is, for example, 1% by weight or more, and may be 5% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, and even 30% by weight or more. The upper limit of the content is, for example, 70% by weight or less, and may be 60% by weight or less, 50% by weight or less, and even 40% by weight or less. Monomer component M does not have to substantially contain cyclic ether group-containing monomers.

[0078] Another example of other monomers is nitrogen atom-containing monomers. A nitrogen atom-containing monomer means a monomer that has at least one nitrogen atom in its molecule (one molecule). Monomer component M may contain one or more nitrogen atom-containing monomers. Monomer component M may contain at least one nitrogen atom-containing monomer selected from the group consisting of the examples below.

[0079] Examples of nitrogen atom-containing monomers are N-vinylcyclic amides and (meth)acrylamides.

[0080] Examples of N-vinylcyclic amides include N-vinyl-2-pyrrolidone (NVP), N-vinyl-2-piperidone, N-vinyl-2-caprolactam, N-vinyl-3-morpholinone, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholindione, and vinylmethyloxazolidinone. Examples of (meth)acrylamides include (meth)acrylamide, N-alkyl(meth)acrylamide, and N,N-dialkyl(meth)acrylamide. (Methacrylamides also include various N-hydroxyalkyl(meth)acrylamides and N-alkoxyalkyl(meth)acrylamides.

[0081] Examples of nitrogen atom-containing monomers other than N-vinylcyclic amides and (meth)acrylamides include amino group-containing monomers such as (meth)aminoethyl acrylate, (meth)dimethylaminoethyl acrylate, (meth)dimethylaminopropyl acrylate, and (meth)t-butylaminoethyl acrylate; cyano group-containing monomers such as acrylonitrile and methacrylonitrile; (meth)acryloylmorpholine, N-vinylpiperazine, N-vinylpyrrole, N-vinylimidazole, N-vinylpyrazine, N-vinylmorpholine, N-vinylpyrazole, vinylpyridine, vinylpyrimidine, vinyloxazole, vinylisoxazole, vinylthiazole, vinylisothiazole, vinylpyridazine, (meth)acryloylpyrrolidone, (meth)acryloylpyrrolidine, (meth)acryloylpiperidine, and N-methylvinyl These include heterocyclic monomers such as rolidone; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-laurylitaconimide, and N-cyclohexylitaconimide; imide group-containing monomers, including succinimide monomers such as N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, and N-(meth)acryloyl-8-oxyoctamethylenesuccinimide; and isocyanate group-containing monomers such as 2-(meth)acryloyloxyethyl isocyanate.

[0082] The nitrogen atom-containing monomer content in monomer component M is, for example, 25% by weight or less, and may be 20% by weight or less, 15% by weight or less, 12% by weight or less, 10% by weight or less, 8% by weight or less, 7% by weight or less, 6% by weight or less, 5% by weight or less, 4% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, and even 0.1% by weight or less. The lower limit of the content is, for example, 0.1% by weight or more, and may be 0.3% by weight or more, 0.5% by weight or more, and even 1% by weight or more. Monomer component M does not have to substantially contain nitrogen atom-containing monomers.

[0083] <1-1-d. Partial Polymers> A portion of the monomer component M may be a partial polymer. In other words, adhesive composition A may contain a partial polymer of monomer component M. The partial polymer may be either a monopolymer or a copolymer. The partial polymer can contribute to the stable formation of the coating layer described later by moderately increasing the viscosity of adhesive composition A. Adhesive composition A does not have to contain a partial polymer of monomer component M.

[0084] The weight-average molecular weight of the partially polymerized material may be greater than, for example, 30,000, and may be 50,000 or more, 100,000 or more, 500,000 or more, or even 1,000,000 or more. The upper limit of the weight-average molecular weight is not particularly limited and may be, for example, 10,000,000 or less, and may be 9,000,000 or less, 8,000,000 or less, 7,000,000 or less, 6,000,000 or less, or even 5,000,000 or less. The weight-average molecular weight is determined from the value calculated by GPC (gel permeation chromatography) and converted to polystyrene equivalent.

[0085] ≪1-2. Photoinitiator≫ Adhesive composition A contains a photoinitiator, which is a type of polymerization initiator. The photoinitiator can contribute to the photopolymerization of monomer component M. The photoinitiator may be a photoradical generator that generates radicals in response to visible light and / or ultraviolet light with wavelengths shorter than 450 nm. The photoinitiator may be a photoradical generator that generates radicals in response to light in the range of 380 nm ± 30 nm, or a photoradical generator that generates radicals in response to light in the range of 380 nm ± 20 nm, 380 nm ± 10 nm, 380 nm ± 5 nm, or even 380 nm.

[0086] Examples of photoinitiators include benzoin ethers such as benzoin methyl ether, benzoin isopropyl ether, and benzyldimethyl ketal; substituted benzoin ethers such as anisole methyl ether; substituted acetophenones such as 2,2-diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone; α-hydroxyalkylphenones such as 1-hydroxycyclohexyl-phenyl ketone; substituted alpha ketols such as 2-methyl-2-hydroxypropiophenone; aromatic sulfonyl chlorides such as 2-naphthalene sulfonyl chloride; photoactive oximes such as 1-phenyl-1,1-propanedione-2-(o-ethoxycarbonyl)-oxime; and benzophenone compounds such as benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylic benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 3,3',4,4'-tetra(t-butylperoxycarbonyl)benzophenone. Thioxanthone compounds such as thioxanthone, 2-chlorthioxanthone, 2-methylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-diethylthioxanthone; 2,4,6-trichloro-s-triazine, 2-phenyl-4,6-bis(trichloromethyl)-s-triazine, 2-(p-methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-(p-tolyl)-4,6-bis(trichloromethyl)-s-triazine, Triazine compounds such as 2-piperonyl-4,6-bis(trichloromethyl)-s-triazine, 2,4-bis(trichloromethyl)-6-styryl-s-triazine, 2-(naphtho-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2-(4-methoxynaphtho-1-yl)-4,6-bis(trichloromethyl)-s-triazine, 2,4-trichloromethyl-(piperonyl)-6-triazine, and 2,4-trichloromethyl-(4'-methoxystyryl)-6-triazine;These include oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)phenyl]octane-1,2-dione 2-(O-benzoyl oxime), and O-(acetyl)-N-(1-phenyl-2-oxo-2-(4'-methoxynaphthyl)ethylidene)hydroxylamine; phosphine compounds such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; quinone compounds such as 9,10-phenanthrenequinone, camphorquinone, and ethylanthraquinone; borate compounds; carbazole compounds; imidazole compounds; and titanocene compounds. However, the photoinitiators are not limited to the above examples. Adhesive composition A may contain one or more photoinitiators.

[0087] Specific examples of photoinitiators include 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad 651, IGM Resins), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819, IGM Resins), 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)2-methylpropan-1-one (Omnirad 127, IGM Resins), and 1-hydroxycyclohexylphenyl ketone (Omnirad 184, IGM Resins).

[0088] The photoinitiator may be an oxime-based photoinitiator such as 1,2-octanedione,1-[4-(phenylthio)phenyl]-,2-(O-benzoyl oxime); (Irgacure OXE01, manufactured by BASF), ethanone,1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazo-3-yl]-,1-(O-acetyl oxime); (Irgacure OXE02, manufactured by BASF), Irgacure OXE03 (manufactured by BASF), or Irgacure OXE04 (manufactured by BASF).

[0089] The photoinitiator may be a polymer-type phosphorus-based initiator such as OmnipolTP (manufactured by IGM Resins, CAS number 1834525-17-5), or ethyl (2,4,6-trimethylbenzoyl)-phenyl phosphenate (Omnirad TPO-L, manufactured by IGM Resins).

[0090] The photoinitiator may have the chemical structure shown in formula (1) within its molecule (within one molecule). However, the "*" in formula (1) indicates a bond site with another atom. The above Omnirad819, OmnipolTP, and Omnirad TPO-L have the chemical structure shown in formula (1) within their molecules.

[0091] Adhesive composition A may contain a photoinitiator having the chemical structure shown in formula (1) within its molecule.

[0092] The photoinitiator may be suitable for suppressing the effect of oxygen-induced curing inhibition on adhesive composition A. Examples of photoinitiators particularly suitable for suppressing the effect of oxygen-induced curing inhibition are Omnirad127, Irgacure OXE01, Irgacure OXE02, Irgacure OXE03, and Irgacure OXE04. Adhesive composition A may contain a photoinitiator suitable for suppressing the effect of oxygen-induced curing inhibition.

[0093] The amount of photoinitiator in adhesive composition A is, for example, 0.01 to 10 parts by weight per 100 parts by weight of monomer component M. The lower limit of the amount may be 0.05 parts by weight or more, 0.1 parts by weight or more, 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, 0.5 parts by weight or more, 0.6 parts by weight or more, 0.7 parts by weight or more, 0.8 parts by weight or more, 0.9 parts by weight or more, 1 part by weight or more, more than 1 part by weight, 1.1 parts by weight or more, 1.2 parts by weight or more, 1.3 parts by weight or more, 1.4 parts by weight or more, and even 1.5 parts by weight or more per 100 parts by weight of monomer component M. The upper limit of the content may be 9 parts by weight or less, 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, 2.5 parts by weight or less, 2 parts by weight or less, 1.5 parts by weight or less, or even 1 part by weight or less per 100 parts by weight of monomer component M.

[0094] Adhesive composition A may contain one or more photoinitiators.

[0095] ≪1-3. Colorants≫ Adhesive composition A contains a colorant. The adhesive formed from adhesive composition A containing a colorant exhibits coloration depending on the type and amount of colorant. Depending on the type and amount of colorant, it is also possible to form an adhesive that has light-shielding properties. Adhesive composition A may contain one or more colorants.

[0096] The coloring agent may be a black coloring agent or a non-black coloring agent. Adhesive composition A may contain a black coloring agent. The use of a black coloring agent is suitable for forming an adhesive with light-shielding properties. Note that the coloring agent, especially the black coloring agent, tends to absorb light, particularly ultraviolet light, when adhesive composition A is cured.

[0097] The coloring agent may contain a metal compound, and a black coloring agent may contain a metal compound. Examples of metal compounds are metal nitride compounds, and more specifically, at least one selected from the group consisting of zirconium nitride and titanium nitride. In other words, the coloring agent may contain at least one selected from the group consisting of zirconium nitride and titanium nitride.

[0098] Another example of a metallic compound is bismuth sulfide. A black coloring agent containing bismuth sulfide is commercially available, for example, LUSHADE BLACK (trade name) manufactured by Ishihara Sangyo Co., Ltd.

[0099] The colorant may contain a dye. The dye may be a metal complex dye. A metal complex dye is a dye that contains a complex salt of a metal atom and a dye molecule. Examples of metal atoms are chromium, copper, cobalt, nickel, iron, manganese, titanium, and aluminum. Examples of dye molecules are azo dyes and methine dyes. The dye may also be a dye salt. Examples of dye salts are salts of various dyes with acids, for example, onium salts of various dyes, alkylbenzene sulfonates, and alkyl diphenyl ether disulfonates. The dye used in the dye salt may be one that is designated as black in the Color Index (C.I.).

[0100] The coloring agent may include carbon compounds such as carbon black, graphite, aniline black, perylene black, cyanine black, and activated carbon. As carbon black, any substance generally referred to as carbon black can be used without particular limitation. Examples of carbon black include furnace black, channel black, acetylene black, thermal black, lamp black, and pine soot. Surface-modified carbon black having functional groups such as carboxyl groups, amino groups, sulfonic acid groups, and silicon-containing groups (e.g., alkoxysilyl groups, alkylsilyl groups) may also be used. Surface-modified carbon black particles are also referred to as self-dispersing carbon black by those skilled in the art and are suitable for reducing the amount of dispersant used.

[0101] Examples of black colorants include carbon compounds such as carbon black, graphite, aniline black, perylene black, cyanine black, and activated carbon; metal compounds such as molybdenum disulfide, chromium complexes, zirconium nitride, and titanium nitride; and organic compound colorants such as anthraquinone-based colorants. The black colorant may also be a pigment or dye containing the above compounds. Adhesive composition A may contain carbon black. The adhesive composition may also contain at least one selected from the group consisting of zirconium nitride and titanium nitride.

[0102] The coloring agent may be in particulate form. The average particle size of the particulate coloring agent may be, for example, 10 nm or more, and may be 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 100 nm or more, or even 150 nm or more. The upper limit of the average particle size is not particularly limited and may be, for example, 3000 nm or less, or 1000 nm or less. The average particle size can be determined by the median diameter d50. If the coloring agent has a shape with a high aspect ratio, for example, in the form of flakes, the average of the major axis may be within the above range.

[0103] The coloring agent may be in non-particulate form.

[0104] Particulate black colorants are suitable for imparting light-shielding properties to adhesives. Particulate black colorants having average particle sizes of 500 nm or less, 300 nm or less, 250 nm or less, and even 200 nm or less, and in some cases 120 nm or less, 100 nm or less, 50 nm or less, 30 nm or less, 25 nm or less, 10 nm or less, 5 nm or less, 2 nm or less, and even 1 nm or less are particularly suitable for imparting light-shielding properties to adhesives.

[0105] Examples of non-black colorants may include colorants that exhibit red, blue, yellow, green, yellow-green, orange, purple, etc. Conventionally known pigments and dyes can be used as non-black colorants. Examples of pigments include inorganic pigments and organic pigments. Examples of dyes include azo dyes, anthraquinone dyes, quinophthalone dyes, styryl dyes, diphenylmethane dyes, triphenylmethane dyes, oxazine dyes, triazine dyes, xanthan gum dyes, methane dyes, azomethine dyes, acridine dyes, and diazine dyes.

[0106] The amount of colorant in adhesive composition A is, for example, 0.1 parts by weight or more per 100 parts by weight of monomer component M, and may be 0.5 parts by weight or more, 1 part by weight or more, 1.5 parts by weight or more, 2 parts by weight or more, 2.2 parts by weight or more, 2.5 parts by weight or more, 3 parts by weight or more, more than 3 parts by weight, 3.5 parts by weight or more, 4 parts by weight or more, 5 parts by weight or more, 6 parts by weight or more, 7 parts by weight or more, 9 parts by weight or more, and even 10 parts by weight or more. The upper limit of the above amount is, for example, 50 parts by weight or less per 100 parts by weight of monomer component M, and may be 40 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 17 parts by weight or less, 15 parts by weight or less, 12 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, and even 8 parts by weight or less. When a solid dispersion is used as a colorant, the content of the colorant in adhesive composition A is calculated based on the weight of the solid content.

[0107] Adhesive composition A may not substantially contain a non-black coloring agent.

[0108] ≪1-4. Other Components≫ Adhesive composition A may contain components other than those described above.

[0109] <1-4-a. Crosslinking Agent> Adhesive composition A may further contain a crosslinking agent. An example of a crosslinking agent is a polyfunctional monomer having two or more polymerizable functional groups in one molecule. The polyfunctional monomer may or may not have the ethylenically unsaturated group described above. The ethylenically unsaturated group may be a (meth)acryloyl group, in other words, the polyfunctional monomer may be a (meth)acrylic monomer. Polyfunctional monomers having an ethylenically unsaturated group tend to contribute mainly to the photopolymerization of monomer component M, in other words, to the formation of adhesive B by photocuring of adhesive composition A. Polyfunctional monomers without an ethylenically unsaturated group tend to contribute mainly to the formation of a cured product when adhesive B formed from adhesive composition A is further cured in a high-temperature environment, when the polyfunctional monomer is included in adhesive composition A together with a thermal initiator. Adhesive composition A may contain a crosslinking agent that is a polyfunctional monomer having an ethylenically unsaturated group, or it may contain a crosslinking agent that is a polyfunctional monomer not having an ethylenically unsaturated group, or it may contain both.

[0110] Examples of polyfunctional monomers having ethylenically unsaturated groups include monomers having two or more ethylenically unsaturated groups in one molecule, and monomers having one or more ethylenically unsaturated groups and one or more polymerizable functional groups such as epoxy groups, aziridine groups, oxazoline groups, hydrazine groups, and methylol groups in one molecule. Polyfunctional monomers having ethylenically unsaturated groups are preferably monomers having two or more ethylenically unsaturated groups in one molecule.

[0111] Examples of polyfunctional monomers having an ethylenically unsaturated group include (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,2-ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate. Polyfunctional acrylates such as acrylate (NDDA), 1,12-dodecanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate (ester compounds of polyhydric alcohols and (meth)acrylic acid, etc.); allyl (meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl di(meth)acrylate, and hexyl di(meth)acrylate. The polyfunctional monomer having an ethylenically unsaturated group is preferably a polyfunctional acrylate, and more preferably trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0112] The content of polyfunctional monomers having ethylenically unsaturated groups in adhesive composition A is, for example, 5 parts by weight or less per 100 parts by weight of monomer component M, and may be 4 parts by weight or less, 3 parts by weight or less, 2.5 parts by weight or less, 2 parts by weight or less, 1.5 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, 0.3 parts by weight or less, 0.2 parts by weight or less, 0.1 parts by weight or less, 0.09 parts by weight or less, 0.08 parts by weight or less, 0.07 parts by weight or less, and even 0.06 parts by weight or less. The lower limit of the above content is, for example, 0.01 parts by weight or more, and may be 0.02 parts by weight or more, 0.03 parts by weight or more, 0.04 parts by weight or more, and even 0.05 parts by weight or more. Adhesive composition A does not have to substantially contain polyfunctional monomers having ethylenically unsaturated groups.

[0113] Adhesive composition A may contain one or more polyfunctional monomers having ethylenically unsaturated groups.

[0114] The polyfunctional monomer without ethylenically unsaturated groups is preferably one that can react with polymers of monomer component M (typically (meth)acrylic polymers). More specifically, the polyfunctional monomer without ethylenically unsaturated groups may include compound C having two or more functional groups α that can react with polymers of monomer component M. The adhesive composition A may contain one or more compounds C.

[0115] The functional group α is preferably a cyclic ether group. That is, the crosslinking agent, which is a polyfunctional monomer that does not have an ethylenically unsaturated group, may contain compound C having two or more cyclic ether groups. Compound C having two or more cyclic ether groups is particularly suitable for combination with adhesive composition A containing monomer component M which contains a cyclic ether group-containing monomer. A cyclic ether group is a functional group that includes a ring having an ether bond. The cyclic ether group may be at least one selected from the group consisting of epoxy groups and oxetane groups, and may be an epoxy group.

[0116] In compound C, the number of functional groups α contained in one molecule is 2 or more, as described above, and may be 3 or more, or even 4 or more. The upper limit of the number of functional groups α is not particularly limited, and may be, for example, 10 or less, 8 or less, 6 or less, or even 5 or less.

[0117] Compound C preferably contains at least one selected from the group consisting of epoxy compounds having two or more epoxy groups and oxetane compounds having two or more oxetane groups, and is particularly preferably an epoxy compound. Examples of epoxy compounds include alicyclic epoxy compounds and aromatic epoxy compounds.

[0118] Examples of alicyclic epoxy compounds include epoxy compounds having epoxycyclohexyl groups, such as butanetetracarboxylic acid tetra(3,4-epoxycyclohexylmethyl)-modified ε-caprolactone (e.g., Epolid GT401 from Daicel Corporation) and 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (e.g., Celoxide 2021 from Daicel Corporation). Commercially available epoxy compounds having epoxycyclohexyl groups include Celoxide 2021P, Celoxide 2081, Celoxide 2083, Celoxide 2085 (all from Daicel Corporation), and Cyracure UVR-6105, Cyracure UVR-6107, Cyracure UVR-6110 (all from Dow Chemical Japan).

[0119] Examples of aromatic epoxy compounds include resorcinol diglycidyl ether and diglycidyl phthalate esters.

[0120] The epoxy compound is not limited to those described above, and may also be epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, diphenyl ether type epoxy resin, hydroquinone type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, fluorene type epoxy resin, polyfunctional epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, and aliphatic chain epoxy resin. These epoxy resins may be halogenated or hydrogenated. Examples of commercially available epoxy resins include JER828, 1001, 801N, 806, 807, 152, 604, 630, 871, YX8000, YX8034, and YX4000 from Mitsubishi Chemical Corporation; Epiclon 830, EXA835LV, HP4032D, and HP820 from DIC Corporation; the EP4100 series, EP4000 series, and EPU series from ADEKA Corporation; the EHPE series from Daicel Corporation; the YD series, YDF series, and YDCN series from Nippon Steel Chemical & Material Corporation; the Denacol series from Nagase ChemteX Corporation; and the Epolite series from Kyoeisha Chemical Co., Ltd.

[0121] Examples of oxetane compounds include 1,4-bis[(3-ethyloxetane-3-yl)methoxymethyl]benzene and bis[(3-ethyloxetane-3-yl)methyl] ether. Commercially available oxetane compounds include Aronoxetane OXT-121 and Aronoxetane OXT-221 (both manufactured by Toagosei Co., Ltd.).

[0122] The content of polyfunctional monomers without ethylenically unsaturated groups in adhesive composition A is, for example, 1 part by weight or more per 100 parts by weight of monomer component M, and may be 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, and even 30 parts by weight or more. The upper limit of the above content is not particularly limited and may be, for example, 80 parts by weight or less, 50 parts by weight or less, and even 40 parts by weight or less. Adhesive composition A may not substantially contain polyfunctional monomers without ethylenically unsaturated groups.

[0123] <1-4-b. Thermal Initiator> Adhesive composition A may further contain a thermal initiator, which is a type of polymerization initiator. However, it is possible to suppress curing defects in adhesive composition A without incorporating a thermal initiator. Adhesive composition A may substantially not contain a thermal initiator.

[0124] The thermal initiator may be at least one selected from the group consisting of azo initiators, peroxide initiators, redox initiators, thermal acid generators, and persulfate initiators, and may also be a thermal acid generator.

[0125] The thermal initiator may be one that promotes the reaction between the polymer of monomer component M and a crosslinking agent (more specifically, a polyfunctional monomer that does not have an ethylenically unsaturated group) under high-temperature conditions.

[0126] Examples of azo initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonnitrile), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], 2,2'-azobis(2-methylpropionamidine) disulfate, and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]. These are 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis(isobutyrate)dimethyl, 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(N,N'-dimethylene isobutylamidine), and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate.

[0127] Examples of peroxide-based initiators include ketone peroxide compounds, peroxyketal compounds, hydroperoxide compounds, dialkyl peroxide compounds, diacyl peroxide compounds, peroxyester compounds, and peroxydicarbonate compounds. More specific examples include diisobutyryl peroxide, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, di(4-t-butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, and t-hexyl peroxyneodecanoate. Noate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di(3,5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, disaxinate peroxide, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, t-hexyl peroxy-2-ethylhexanoate t-butyl peroxy-2-ethylhexanoate, di(3-methylbenzoyl) peroxide, benzoyl(3-methylbenzoyl) peroxide, dibenzoyl peroxide, 1,1-di(t-hexyl peroxy)cyclohexane, 1,1-di(t-butyl peroxy)cyclohexane, 2,2-di(4,4-di(t-butyl peroxy)cyclohexyl)propane, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxide Oxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butyl peroxyacetate, 2,2-di-(t-butylperoxy)butane, t-butyl peroxybenzoate, n-butyl-4,These include 4-di-(t-butylperoxy)valerate, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, p-menthane hydroperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyn-3, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide, 2,3-dimethyl-2,3-diphenylbutane, and mixtures thereof.

[0128] Examples of redox initiators are initiators that combine a peroxide and a reducing agent. Examples of combinations include persulfate and sodium bisulfite, and peroxide and sodium ascorbate.

[0129] A thermal acid generator generates acid in a high-temperature environment. From this perspective, a thermal acid generator is particularly suitable for promoting the reaction between a polymer of monomer component M and a crosslinking agent (more specifically, a polyfunctional monomer that does not have an ethylenically unsaturated group) in a high-temperature environment.

[0130] Examples of thermal acid generators include cationic or protonic acid catalysts such as sulfonium salts, ammonium salts, pyridinium salts, phosphonium salts, iodonium salts, trifluates, boron trifluoride ether complex compounds, and boron trifluoride. The thermal acid generator may also be an onium salt that generates a cationic species upon heat.

[0131] The thermal acid generator may be a sulfonium salt or a phosphonium salt, or it may be a sulfonium salt.

[0132] Examples of sulfonium ions contained in sulfonium salts 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, benzyl(4-acetoxyphenyl)methylsulfonium, (4-acetoxyphenyl)benzyl(methyl)sulfonium = tetrakis(pentafluorophenyl)borate, and (4-hydroxyphenyl)methyl(4-methylbenzyl)sulfonium = tetrakis(pentafluorophenyl)borate.

[0133] Examples of counterions contained in sulfonium salts include tris(pentafluoroethyl)trifluorophosphate, hexafluorophosphate, tetrakis(pentafluorophenyl)borate, hexafluoroantimonate, p-toluenesulfonate, dodecylbenzenesulfonate, trifluoromethanesulfonate, and perfluorobutanesulfonate. It is preferable that the sulfonium salt contains a borate ion such as tetrakis(pentafluorophenyl)borate.

[0134] Examples of commercially available thermal acid generators include San-Aid SI-45L, San-Aid SI-60L, San-Aid SI-80L, San-Aid SI-100L, San-Aid SI-150L, ​​San-Aid SI-45, San-Aid SI-60, San-Aid SI-80, San-Aid SI-100, San-Aid SI-110, San-Aid SI-150, San-Aid SI-300, San-Aid SI-360, San-Aid SI-B2A, San-Aid SI-B3, San-Aid SI-B3A, San-Aid SI-B4, San-Aid SI-B5, and San-Aid SI-B7, all manufactured by San-Shin Chemical Industry Co., Ltd., with San-Aid SI-B3, San-Aid SI-B3A, and San-Aid SI-B7 being preferred.

[0135] The thermal decomposition temperature of the thermal acid generator (the temperature required to generate acid) is, for example, 60°C or higher, but may be 70°C or higher, 80°C or higher, 90°C or higher, 100°C or higher, 110°C or higher, or even 120°C or higher. The upper limit of the thermal decomposition temperature is, for example, 200°C or lower, but may be 180°C or lower, or even 160°C or lower.

[0136] The heat acid generator may be an amine compound. Examples of amine compounds include aliphatic polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and diethylaminopropylamine; alicyclic polyamines such as mensendiamine, isophoronediamine, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5,5)undecane adduct, bis(4-amino-3-methylcyclohexyl)methane, and bis(4-aminocyclohexyl)methane; m-phenylenediamine, p-phenylenediamine, o-xylenediamine, m-xylenediamine, p-xylenediamine, 4,4-diaminodiphenylmethane, 4,4-diaminodiphenylpropane, 4,4-diaminodiphenylsulfone, 4,4-diaminodicyclohexane, bis(4-aminophenyl)phenylmethane, 1,5-diaminonaphthalene, and 1,1-bis(4-aminophenyl) Aromatic polyamines such as chlorohexane, 2,2-bis[(4-aminophenoxy)phenyl]propane, bis[4-(4-aminophenoxy)phenyl]sulfone, 1,3-bis(4-aminophenoxy)benzene, 4,4-methylene-bis(2-chloroaniline), and 4,4-diaminodiphenylsulfone; carbodihydrazides, adipic acid dihydrazides, sebacate dihydrazides, dodecanediic acid dihydrazides, and isophthalic acid dihydrazides. Examples of hydrazides include dicyandiamide, 1-o-tolyl diguanide, α-2,5-dimethylguanide, α,ω-diphenyl diguanidide, α,α-bisguanylguanidinodiphenyl ether, p-chlorophenyl diguanide, α,α-hexamethylenebis[ω-(p-chlorophenol)]diguanide, phenyl diguanide oxalate, acetylguanidine, diethylcyanoacetylguanidine, and other guanidine derivatives.

[0137] Examples of persulfate initiators are potassium persulfate and ammonium persulfate.

[0138] The thermal initiator is not limited to the examples given above.

[0139] The self-accelerating decomposition temperature (SADT) of thermal initiators, particularly peroxide-based initiators, may be 120°C or lower, 100°C or lower, 90°C or lower, 85°C or lower, 80°C or lower, 75°C or lower, 70°C or lower, 65°C or lower, 60°C or lower, 55°C or lower, 50°C or lower, 45°C or lower, 40°C or lower, 35°C or lower, 30°C or lower, 25°C or lower, 20°C or lower, 15°C or lower, 10°C or lower, or even 5°C or lower. Thermal initiators with low SADTs may allow for more effective utilization of the heat generated in the adhesive composition A by light irradiation. The lower limit of SADT is, for example, 0°C or higher. Note that SADT is well known to those skilled in the art.

[0140] The amount of thermal initiator in adhesive composition A is, for example, 0.01 to 10 parts by weight per 100 parts by weight of monomer component M, and may be 0.05 to 5 parts by weight, 0.1 to 3 parts by weight, 0.1 to 2 parts by weight, 0.1 to 1.5 parts by weight, 0.1 to 1 part by weight, 0.1 to 0.9 parts by weight, 0.1 to 0.8 parts by weight, 0.1 to 0.7 parts by weight, 0.1 to 0.6 parts by weight, 0.1 to 0.5 parts by weight, 0.1 to 0.4 parts by weight, 0.1 to 0.3 parts by weight, or even 0.1 to 0.2 parts by weight.

[0141] Adhesive composition A may contain one or more thermal initiators.

[0142] <1-4-c. Inorganic Particles> The adhesive composition A may further contain inorganic particles (more specifically, inorganic particles other than colorants). Inorganic particles are suitable for improving the refractive index of the adhesive. It is preferable that the inorganic particles are dispersed in the adhesive composition A. The adhesive composition A may contain one or more types of inorganic particles.

[0143] Inorganic particles can be selected from, for example, metal compound particles and metal particles, one or more types depending on the desired purpose, such as improving the refractive index. Metal compound particles may also be metal oxide particles. Examples of materials constituting metal oxide particles include titanium oxide, zirconium oxide, cerium oxide, aluminum oxide, zinc oxide, tin oxide, copper oxide, barium titanate, and niobium oxide. Metal oxide particles can be used individually or in combination of two or more types. Inorganic particles preferably contain zirconium oxide, and may also be zirconium oxide particles composed substantially solely of zirconium oxide. Zirconium oxide particles can particularly contribute to increasing the refractive index of the adhesive.

[0144] The materials constituting the metal compound particles may include metal hydroxides such as aluminum hydroxide, boehmite, magnesium hydroxide, calcium hydroxide, zinc hydroxide, iron hydroxide, copper hydroxide, barium hydroxide, basic magnesium carbonate, and hydrotalcite, as well as hydrated metal compounds. Examples of materials constituting the metal particles are iron, zinc, tungsten, and platinum.

[0145] The inorganic particle material may be a high-entropy alloy in which multiple types of elements are mixed.

[0146] Inorganic particles may be surface-treated. One example of surface treatment is hydrophobic treatment.

[0147] The inorganic particles may contain high refractive index materials. The refractive index of the high refractive index material may be, for example, 1.60 or higher, 1.70 or higher, 1.80 or higher, or even 2.00 or higher. The upper limit of the refractive index of the high refractive index material is not particularly limited, and may be, for example, 3.00 or lower, 2.80 or lower, 2.50 or lower, or even 2.20 or lower. The refractive index of the material contained in the inorganic particles can be determined as the refractive index measured on a single layer film of the material using a commercially available spectroscopic ellipsometer at 23°C and 549 nm. For example, the spectroscopic ellipsometer "EC-400" (manufactured by JA. Woolam) or an equivalent product can be used.

[0148] The inorganic particles may be nanoparticles having an average particle diameter of less than 1 μm. The average particle diameter of the inorganic particles may be 100 nm or less. The average particle diameter may be 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, 10 nm or less, 7 nm or less, 5 nm or less, and even 4 nm or less. The lower limit of the average particle diameter is, for example, 1 nm or more, and may be 1.5 nm or more, 2 nm or more, and even 2.5 nm or more.

[0149] The inorganic particle content in adhesive composition A is, for example, 0.1 parts by weight or more per 100 parts by weight of monomer component M, and may be 0.5 parts by weight or more, 1 part by weight or more, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, 40 parts by weight or more, 45 parts by weight or more, 50 parts by weight or more, 55 parts by weight or more, 60 parts by weight or more, 65 parts by weight or more, 70 parts by weight or more, 75 parts by weight or more, 80 parts by weight or more, 90 parts by weight or more, and even 100 parts by weight or more. The upper limit of the above content is, for example, 150 parts by weight or less per 100 parts by weight of monomer component M, and may be 140 parts by weight or less, 130 parts by weight or less, 120 parts by weight or less, 115 parts by weight or less, and even 110 parts by weight or less. Adhesive composition A does not have to contain inorganic particles substantially. In addition, inorganic particles can be incorporated into adhesive composition A in the form of a dispersion; in this case, the inorganic particle content is calculated based on the weight of the solid content.

[0150] <1-4-d. Dispersant> The adhesive composition A may further contain a dispersant. Examples of dispersants include a component for sufficiently dispersing a colorant in the adhesive composition A (hereinafter referred to as "colorant dispersant") and a component for sufficiently dispersing inorganic particles in the adhesive composition A (hereinafter referred to as "inorganic particle dispersant").

[0151] Any known dispersant can be used as the dispersant for the colorant. Adhesive composition A may not contain a dispersant for the colorant.

[0152] The dispersant for inorganic particles is preferably in contact with the surface of the inorganic particles, and more preferably coating the surface of the inorganic particles.

[0153] An example of an inorganic particle dispersant is a compound having both a hydrophilic and a hydrophobic part in a single molecule. The hydrophilic and hydrophobic parts are presumed to exhibit relatively high affinity for the inorganic particles and the monomer component M, respectively. The inorganic particle dispersant may or may not have polymerizable functional groups such as ethylenically unsaturated groups.

[0154] The hydrophilic portion preferably has hydrophilic groups. Examples of hydrophilic groups are ether groups and ester groups.

[0155] The hydrophilic portion preferably has a functional group F that exhibits adsorption or reactivity to inorganic particles. An example of a functional group F is at least one selected from the group consisting of alkaline groups and acidic groups. Specific examples of functional groups F are hydroxyl groups, carboxyl groups, nitrogen atom-containing groups, sulfur atom-containing groups, phosphorus atom-containing groups, and silicon atom-containing groups. The number of functional groups F in one molecule of the inorganic particle dispersant may be one or two or more (for example, about 2 to 5). The two or more types of functional groups F present in one molecule may be the same or different from each other.

[0156] The hydrophilic portion may have a chain-like structure, or a composite structure of a chain-like structure and a ring-like structure. Dispersants for inorganic particles may include, for example, a structure in which a functional group F and a hydrophobic portion are linked via a chain-like structure; a structure in which a functional group F is present on a side chain of a chain-like structure with one end linked to a hydrophobic portion; and a structure in which a functional group F is not present at the other end of a chain-like structure with one end linked to a hydrophobic portion (for example, the other end of the chain-like structure is open). Dispersants for inorganic particles may have two or more of the above structures.

[0157] The dispersant for inorganic particles may be an aromatic compound having an aromatic ring. Examples of aromatic rings are the same as those described above in the explanation of monomer a.

[0158] The dispersant for inorganic particles may be selected from known surfactants. Examples of surfactants include anionic surfactants (carboxylic acid type, phosphate ester type, sulfate ester type, sulfonic acid type, etc.), nonionic surfactants, cationic surfactants, and amphoteric surfactants. The surfactant that can be used as a dispersant for inorganic particles is preferably anionic surfactant.

[0159] The amount of inorganic particle dispersant blended per 100 parts by weight of inorganic particles is, for example, 0.1 parts by weight or more, and may be 0.5 parts by weight or more, 1 part by weight or more, 3 parts by weight or more, 5 parts by weight or more, or even 10 parts by weight or more. The upper limit of the blending amount is, for example, 30 parts by weight or less, and may be 20 parts by weight or less. Adhesive composition A does not need to contain substantially any inorganic particle dispersant.

[0160] <1-4-e. Silane Coupling Agents> Adhesive composition A may further contain silane coupling agents. Adhesive composition A may contain one or more silane coupling agents.

[0161] Examples of silane coupling agents include epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-γ-aminopropyltrimethoxysilane; (meth)acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatetopropyltriethoxysilane.

[0162] The content of the silane coupling agent in adhesive composition A is, for example, 5 parts by weight or less per 100 parts by weight of monomer component M, and may be 3 parts by weight or less, 1 part by weight or less, 0.8 parts by weight or less, 0.5 parts by weight or less, 0.4 parts by weight or less, 0.3 parts by weight or less, 0.2 parts by weight or less, and even 0.1 parts by weight or less. The lower limit of the above content is, for example, 0.01 parts by weight or more, and may even be 0.05 parts by weight or more. Adhesive composition A may not contain substantially any silane coupling agent.

[0163] <1-4-f. Antioxidants> Adhesive composition A may further contain antioxidants. Adhesive composition A may contain one or more antioxidants.

[0164] Examples of antioxidants include phenolic antioxidants, hindered phenolic antioxidants, amine antioxidants, and phosphite antioxidants.

[0165] Examples of phenolic antioxidants include monophenolic antioxidants, bisphenolic antioxidants, and polymeric phenolic antioxidants. Examples of monophenolic antioxidants include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, and stearin-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate. Examples of bisphenol antioxidants include 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), and 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10-tetraoxaspiro[5,5]undecane. Examples of high molecular weight phenolic antioxidants include 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)butyric acid]glycol ester, 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-S-triazine-2,4,6-(1H,3H,5H)trione, and tocopherol.

[0166] Hindered phenol antioxidants may have a structure in which a tert-butyl group is bonded to at least one carbon atom adjacent to the carbon atom on the aromatic ring to which the OH group of phenol is bonded. Examples of hindered phenol antioxidants include dibutylhydroxytoluene (BHT); and Irganox 1010, Irganox 1010FF, Irganox 1035, Irganox 1035FF, Irganox 1076, Irganox 1076FD, Irganox 1076DWJ, Irganox 1098, Irga These are the NOX 1135, Irganox 1330, Irganox 1726, Irganox 1425WL, Irganox 1520L, Irganox 245, Irganox 245FF, Irganox 259, Irganox 3114, Irganox 565, and Irganox 295 (all are brand names and manufactured by BASF).

[0167] The amine-based antioxidant is preferably a hindered amine-based antioxidant. The hindered amine-based antioxidant may have at least one hindered piperazine group in one molecule. Examples of hindered amine-based antioxidants are AdekaStab LA-63, AdekaStab LA-63P, AdekaStab LA-52, and AdekaStab LA-57 (all are trade names and manufactured by ADEKA Corporation).

[0168] Examples of phosphite antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, and phenyl diisodecyl phosphite; as well as Adeka Stab 2112, Adeka Stab 2112RG, Adeka Stab 1178, and Adeka Stab 3010 (all trade names, manufactured by ADEKA).

[0169] The antioxidant content in adhesive composition A is, for example, 5 parts by weight or less per 100 parts by weight of monomer component M, and may be 3 parts by weight or less, 1 part by weight or less, 0.8 parts by weight or less, or even 0.5 parts by weight or less. The lower limit of the above content is, for example, 0.01 parts by weight or more, and may even be 0.05 parts by weight or more. Adhesive composition A may not contain substantially any antioxidant.

[0170] <1-4-g. Curing Accelerator> Adhesive composition A may further contain a curing accelerator. Adhesive composition A may contain one or more curing accelerators.

[0171] Examples of curing accelerators are compounds that exhibit oxygen absorption. Compounds that exhibit oxygen absorption can contribute to suppressing curing inhibition by oxygen during photocuring. Another example of a curing accelerator is a compound having an isoprenyl group and a methacryloyl group within the molecule (within one molecule). Another example of a curing accelerator is a compound having a secondary thiol group. The secondary thiol group can promote polymerization by becoming a thiol radical itself by donating hydrogen to a peroxide radical, and can also contribute to suppressing oxygen inhibition. It is preferable that there are multiple secondary thiol groups in one molecule.

[0172] Specific examples of curing accelerators include diprenyl glycerin ether (DPNG), isoprenyl methacrylate (IPEMA), pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(2-(3-sulfanylbutanoyloxy)ethyl)-1,3,5-triazinan-2,4,6-trione, and trimethylolpropane-tris(3-mercaptobutyrate). DPNG exhibits oxygen absorption properties.

[0173] The content of the curing accelerator in adhesive composition A is, for example, 10 parts by weight or less per 100 parts by weight of monomer component M, and may be 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, 1.5 parts by weight or less, 1 part by weight or less, 0.8 parts by weight or less, and even 0.5 parts by weight or less. The lower limit of the above content is, for example, 0.01 parts by weight or more, and may be 0.05 parts by weight or more, 0.1 parts by weight or more, 0.3 parts by weight or more, and even 0.5 parts by weight or more. Adhesive composition A may not contain substantially any curing accelerator.

[0174] <1-4-h. Photosensitizer> Adhesive composition A may further contain a photosensitizer. Adhesive composition A may contain one or more photosensitizers.

[0175] Examples of photosensitizers include benzophenone, methyl o-benzoylbenzoate, 2-isopropylthioxanthone, and 9,10-dibutoxyanthracene.

[0176] The amount of photosensitizer in adhesive composition A is, for example, 5 parts by weight or less, and may be 3 parts by weight or less, 1 part by weight or less, 0.8 parts by weight or less, or even 0.5 parts by weight or less, based on 100 parts by weight of monomer component M. The lower limit of the above amount is, for example, 0.01 parts by weight or more, and may even be 0.05 parts by weight or more. Adhesive composition A may not contain substantially any photosensitizer.

[0177] <1-4-i. Additives> Adhesive composition A may further contain additives (excluding the components described above). Examples of additives include chain transfer agents, viscosity modifiers, tackifiers, plasticizers, softeners, anti-aging agents, fillers, surfactants, antistatic agents, leveling agents, flame retardants, and ultraviolet absorbers. Adhesive composition A may be substantially free of additives.

[0178] ≪1-5. Viscosity≫ The viscosity of adhesive composition A is preferably 5 to 300 poise at 25°C. Adhesive composition A having a viscosity within the above range is particularly suitable for forming the coating layer described later.

[0179] ≪1-6. Method for Producing Adhesive Composition A≫ Adhesive composition A can be formed, for example, by selecting components to be incorporated into the composition and mixing the selected components. It is preferable to mix the colorant in a dispersed state in the monomer. The monomer used to disperse the colorant is included in monomer component M after the colorant is mixed. The monomer used to disperse the colorant may be the same as or different from the monomer included in monomer component M before the colorant is mixed.

[0180] ≪≪2. Adhesive≫≫ The adhesive according to the embodiment of the present invention (hereinafter referred to as "adhesive B") is an adhesive formed from adhesive composition A. Adhesive B is usually formed by the curing of adhesive composition A.

[0181] ≪2-1. Characteristics, etc.≫ The curing state of adhesive B can be expressed by the polymerization rate of monomer component M in adhesive B. The polymerization rate of monomer component M is, for example, 90.0% or more, 91.0% or more, 92.0% or more, 93.0% or more, 94.0% or more, 95.0% or more, 95.2% or more, 95.4% or more, 95.5% or more, 95.6% or more, 95.8% or more, 96.0% or more, 96.2% or more, 96.4% or more, 96.5% or more, 96.7% or more, 96.9% or more, 97.0% or more, 97.2% or more, 97.4% or more, The polymerization rate may be 97.5% or higher, 97.7% or higher, 97.9% or higher, 98.0% or higher, 98.1% or higher, 98.2% or higher, 98.3% or higher, 98.4% or higher, 98.5% or higher, 98.6% or higher, 98.7% or higher, 98.8% or higher, 98.9% or higher, 99.0% or higher, 99.1% or higher, 99.2% or higher, 99.3% or higher, 99.4% or higher, 99.5% or higher, 99.6% or higher, and even 99.7% or higher. The upper limit of the polymerization rate may be, for example, less than 100%, and may be 99.9% or lower, and even 99.8% or lower.

[0182] Adhesive B is CIE1976 L as defined in Japanese Industrial Standard (JIS) Z8781-4:2013. * , a * , b * L in color space * The L of adhesive B may be displayed as follows, and may have a brightness of 60.0 or less. * It may be 55.0 or less, 50.0 or less, 45.0 or less, 40.0 or less, 35.0 or less, 30.0 or less, 25.0 or less, 20.0 or less, 15.0 or less, 10.0 or less, 9.0 or less, 8.0 or less, 7.0 or less, 6.0 or less, 5.5 or less, 5.0 or less, 4.5 or less, 4.0 or less, 3.5 or less, 3.2 or less, 3.0 or less, 2.7 or less, 2.5 or less, 2.2 or less, 2.0 or less, 1.7 or less, 1.5 or less, 1.2 or less, 1.0 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less, 0.3 or less, 0.2 or less, and even 0.1 or less. * It can be 0.0. The content of colorants, especially black colorants, is L * It is suitable for lowering the value of [this].

[0183] Adhesive B is L* , a * , b * a in color space * The absolute value of has a chromaticity of 10.0 or less, and b * The absolute value of may indicate that the chromaticity is 10.0 or less. * The absolute value of and b * The absolute values ​​of the numbers, independently of each other or both, may be less than or equal to 9.5, less than or equal to 9.0, less than or equal to 8.5, less than or equal to 8.0, less than or equal to 7.5, less than or equal to 7.0, less than or equal to 6.5, less than or equal to 6.0, less than or equal to 5.5, less than or equal to 5.0, less than or equal to 4.5, less than or equal to 4.0, less than or equal to 3.5, less than or equal to 3.0, less than or equal to 2.5, less than or equal to 2.2, less than or equal to 2.0, less than or equal to 1.8, less than or equal to 1.6, less than or equal to 1.5, less than or equal to 1.4, less than or equal to 1.3, less than or equal to 1.2, less than or equal to 1.1, less than or equal to 1.0, less than or equal to 0.9, less than or equal to 0.8, less than or equal to 0.7, less than or equal to 0.6, less than or equal to 0.5, less than or equal to 0.4, less than or equal to 0.3, less than or equal to 0.2, and even less than or equal to 0.1. * The absolute value of and b * The absolute value of L can be 0.0. * Lowering the value of a * and b * You may choose a coloring agent that lowers the absolute value of [the colorant].

[0184] Brightness L of adhesive B * and chromaticity a * , b * This can be evaluated using a commercially available colorimeter capable of measurement in accordance with JIS Z8781-4:2013. However, the adhesive B should be in the form of a sheet with a thickness of 25 μm when evaluated. Furthermore, to facilitate handling, it is preferable to evaluate it in a laminated state with a supporting film or sheet.

[0185] Adhesive B may have a total light transmittance Tt of 91% or less. Total light transmittance Tt can be 90% or less, 85% or less, 80% or less, 75% or less, 70% or less, 65% or less, 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 17% or less, 15% or less, 12% or less, 10% or less, 9% or less, 7% or less, 5% or less, less than 5%, 4.5% or less, 4% or less, 3.5% or less, 3% or less, 2 It may be 5% or less, 2% or less, 1.5% or less, 1% or less, 0.8% or less, 0.6% or less, 0.5% or less, less than 0.5%, 0.45% or less, 0.4% or less, 0.35% or less, 0.3% or less, 0.25% or less, 0.2% or less, 0.15% or less, 0.1% or less, less than 0.1%, 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less, and even 0.01% or less. The lower limit of the total light transmittance Tt is, for example, 0.0001% or more. The total light transmittance Tt of adhesive B can be evaluated using a commercially available spectroscopic measuring instrument capable of measurement in accordance with JIS R3106, such as a spectrophotometer (for example, Hitachi High-Tech Corporation's UV-Vis-Near-Infrared Spectrophotometer UH4150 or an equivalent). However, the adhesive B used for evaluation should be in the form of a sheet with a thickness of 25 μm. Furthermore, to facilitate handling, it is preferable to evaluate it in a laminated state with a support substrate sheet or film.

[0186] Adhesive B may have a haze of 5 to 100%. The lower limit of the haze may be 10% or more, 15% or more, 20% or more, 25% or more, 30% or more, 35% or more, or even 40% or more. The haze may be 45 to 90%, 50 to 80%, or even greater than 50%. In this specification, haze means the ratio of diffusely transmitted light to total transmitted light when visible light is irradiated onto the adhesive, which is the object to be measured. The haze can be calculated by the following formula. In the following formula, Th is haze (%), Td is scattered light transmittance, and Tt is total light transmittance. Th (%) = (Td / Tt) × 100

[0187] The haze of adhesive B can be evaluated using a commercially available spectroscopic measuring instrument capable of measurement in accordance with JIS K7136, such as a haze meter. However, the shape of adhesive B for evaluation should be a sheet with a thickness of 25 μm. Furthermore, to facilitate handling, it is preferable to evaluate it in a laminated state with a support substrate sheet or film.

[0188] Adhesive B may have a refractive index of 1.50 or higher. The refractive index may be 1.51 or higher, 1.52 or higher, 1.53 or higher, 1.54 or higher, 1.55 or higher, 1.56 or higher, 1.57 or higher, 1.58 or higher, 1.59 or higher, 1.60 or higher, 1.61 or higher, 1.62 or higher, 1.63 or higher, 1.64 or higher, and even 1.65 or higher. The upper limit of the refractive index is, for example, 1.70 or lower, and may be 1.69 or lower, 1.68 or lower, 1.67 or lower, 1.66 or lower, and even 1.65 or lower.

[0189] The refractive index of adhesive B can be measured at a measurement temperature of 25°C using a digital refractometer (for example, Atago RX-9000α digital refractometer or equivalent). However, the adhesive B should be in sheet form for evaluation, and the refractive index of the sheet surface should be measured. The measurement is performed using the reflection method, which utilizes total internal reflection at the interface between the adhesive and the prism.

[0190] The gel fraction of adhesive B is, for example, 50% or more, and may be 75% or more, 80% or more, 85% or more, or even 90% or more.

[0191] The gel fraction can be measured by the following method. First, a small piece is obtained by scraping off a portion of adhesive B. Next, the obtained small piece is wrapped in a stretched porous film of polytetrafluoroethylene and tied with kite string. This yields a test specimen. Next, the total weight (weight W) of the small piece of adhesive B, the stretched porous film, and the kite string is measured. a ) is measured. The total weight of the stretched porous membrane and kite string used is W. b This is defined as follows. Next, the test specimen is immersed in a container filled with toluene and left to stand at 23°C for one week. After standing, the test specimen is removed from the container and dried in a drying oven set to 130°C for two hours, and then the weight W of the test specimen is measured. c Measure the weight W based on the following formula.a , W b and W c The gel fraction of adhesive B can be determined from this. Gel fraction (weight %) = (W c -W b ) / (W a -W b ) × 100

[0192] The shear storage modulus G' of adhesive B at 25°C is 1.0 × 10⁻⁶. 5 It may be less than or equal to Pa, 9.0 × 10 4 Pa or less, 8.0×10 4 Below Pa, and even 7.0 x 10 4 It may be less than or equal to Pa. The lower limit of the shear storage modulus G' of adhesive B is, for example, 1.0 × 10 3 It may be Pa or higher, 5.0 × 10 3 Pa or more, 1.0×10 4 Pa or more, 3.0×10 4 Pa or higher, and even 5.0 x 10 4 It may be Pa or higher. The shear storage modulus G' of adhesive B at 25°C is not limited to the above range, but adhesive B having G' within the above range is particularly suitable for excellent adhesion to members and for sufficiently increasing the adhesive strength between members after they have been joined together.

[0193] The shear storage modulus G' of adhesive B at 25°C can be measured by the following method. First, a sample for measurement composed of adhesive B is prepared. The sample for measurement is disc-shaped. The sample for measurement has a base diameter of 7.9 mm and a thickness of approximately 1 mm. The sample for measurement may also be obtained by stacking multiple adhesive sheets composed of adhesive B and pressing them together, then punching out the resulting laminate into a disc shape. Next, dynamic viscoelasticity measurement is performed on the sample for measurement under the following measurement conditions. For dynamic viscoelasticity measurement, for example, a dynamic viscoelasticity measuring device (Advanced Rheometric Expansion System (ARES)) manufactured by TA Instruments can be used. From the results of the dynamic viscoelasticity measurement, the shear storage modulus of the sample for measurement at 25°C is determined, and the obtained value is considered to be the shear storage modulus G' of the adhesive. Measurement conditions: Deformation mode: Torsion Measurement frequency: 1 Hz Temperature range: -40°C to 150°C Heating rate: 5°C / min Shape: Parallel plate 7.9 mmφ

[0194] For adhesive B, the adhesive strength determined by the following tests may be 0.1 N / 20 mm or more, 0.2 N / 20 mm or more, 0.5 N / 20 mm or more, 1.0 N / 20 mm or more, 1.5 N / 20 mm or more, 2 N / 20 mm or more, 2.5 N / 20 mm or more, 3 N / 20 mm or more, 4 N / 20 mm or more, 5 N / 20 mm or more, 6 N / 20 mm or more, 7 N / 20 mm or more, 8 N / 20 mm or more, 9 N / 20 mm or more, 10 N / 20 mm or more, 15 N / 20 mm or more, 20 N / 20 mm or more, 25 N / 20 mm or more, and even 30 N / 20 mm or more. The upper limit of the adhesive strength is not limited; for example, it may be 50 N / 20 mm or less, 40 N / 20 mm or less, and even 30 N / 20 mm or less.

[0195] (Adhesion Test) A test specimen is prepared, which is a laminate of the adhesive B to be evaluated and an evaluation substrate sheet. The shape of the adhesive B is a sheet with a thickness of 25 μm. The evaluation substrate sheet is not limited as long as it does not peel off from the adhesive B during the peel test from the surface of alkali-free glass performed in this test and a peel test (180° peel test) can be performed. For example, polyethylene terephthalate (PET) sheets can be used as the evaluation substrate sheet. The bonding surface of adhesive B on the evaluation substrate sheet may be treated to improve adhesion, such as corona treatment. As long as the above conditions are met, the substrate sheet or release liner used to form the sheet-like adhesive B may be used as the evaluation substrate sheet. The test specimen is prepared so that the shape of the part of the evaluation substrate sheet to which adhesive B is bonded is a rectangle with a width of 25 mm and a length of 80 mm, and the part consisting only of the evaluation substrate sheet is a rectangle with a width of 25 mm and a length of 170 mm. The overall shape of the test specimen is a rectangle measuring 25 mm in width and 250 mm in length.

[0196] Next, the test piece is placed on top of the alkali-free glass via adhesive B, and a 2 kg hand roller is passed back and forth once to press them together. Alkali-free glass is glass that is substantially free of alkali components (alkali metal oxides), and more specifically, the weight ratio of alkali components in the glass is, for example, 1000 ppm (by weight, the same applies hereinafter) or less, and moreover, 500 ppm or less. Alkali-free glass is, for example, in the form of a plate and has a thickness of 0.5 mm or more. In order to perform the measurement more accurately, it is advisable to clean the bonding surface of adhesive B on the alkali-free glass using isopropyl alcohol or the like.

[0197] Next, the test specimen bonded to the alkali-free glass is left at room temperature (23°C ± 5°C) for 30 minutes. Then, it is placed in a pressurized degassing device (autoclave) and autoclaved for 15 minutes at a temperature of 50°C and a pressure of 0.5 MPa. After the treatment, it is left at room temperature for 12 hours. Next, a peel test is performed with a peel angle of 180° and a peel speed of 300 mm / min to peel the test specimen from the alkali-free glass. The maximum value of the force (peel strength) measured during peeling can be identified as the adhesive strength of adhesive B.

[0198] Adhesive B may possess any combination of the two or more properties described above.

[0199] The shape of adhesive B is not limited. Adhesive B may be in sheet form, or it may be in an amorphous or bulk form with a predetermined shape. Adhesive B may have any shape depending on the application.

[0200] The thickness of the sheet-like adhesive B is, for example, 2 mm or less, and may be 1.5 mm or less, 1 mm or less, 500 μm or less, 250 μm or less, 100 μm or less, 50 μm or less, 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, 5 μm or less, 4 μm or less, or even 3 μm or less. The lower limit of the thickness of the sheet-like adhesive B is, for example, 2 μm or more.

[0201] The applications of adhesive B are not limited. Examples of applications include optical and decorative purposes. Adhesive B may also be used as an adhesive-coated optical component in combination with an optical component.

[0202] Adhesive B may be used in electronic devices such as portable electronic devices. Non-limiting examples of portable electronic devices include mobile phones, smartphones, tablet computers, notebook computers, various wearable devices (e.g., wristwear type worn on the wrist like a watch, modular type attached to a part of the body with a clip or strap, eyewear type including glasses (monocular and binocular types, including head-mounted types), clothing type attached to shirts, socks, hats, etc. as an accessory, earwear type attached to the ear like an earphone, etc.), digital cameras, digital video cameras, audio equipment (portable music players, IC recorders, etc.), calculators (calculators, etc.), portable game devices, electronic dictionaries, electronic organizers, e-books, in-car information equipment, portable radios, portable televisions, portable printers, portable scanners, portable modems, etc. In this specification, "portable" means not merely being able to carry, but having a level of portability that allows an individual (a typical adult) to carry it relatively easily.

[0203] Adhesive B contains a coloring agent. The light transmittance of adhesive B may be limited by the inclusion of the coloring agent. Furthermore, depending on the composition of adhesive composition A, such as the type and content of monomers contained in monomer component M, adhesive B may have a high refractive index. Adhesive B with limited light transmittance and adhesive B with a high refractive index may be particularly suitable for use in electronic devices such as portable electronic devices. For example, some electronic devices contain light-emitting elements for purposes such as image display, and limited light transmittance (e.g., light shielding) may be required for the adhesive. Also, high refractive index materials may be used in electronic devices, and a high refractive index adhesive may be required to prevent unwanted reflections. Adhesive B, having the above characteristics, is particularly suitable for meeting such requirements.

[0204] ≪2-2. Method for Manufacturing Adhesive B≫ Adhesive B can be formed by curing the adhesive composition A described above by irradiating it with light. The method for manufacturing adhesive B according to this embodiment includes curing the adhesive composition A described above by irradiating it with light.

[0205] Figure 1 shows an example of a method for manufacturing adhesive B according to this embodiment. In the example shown in Figure 1, light 13 is irradiated onto a coating 12 of adhesive composition A placed on a substrate 11. The coating 12 hardens upon irradiation with light 13, forming adhesive 14. The formed adhesive 14 may be transferred to various members, which are the objects to which the adhesive 14 should be placed. The member that is the object can also be used as the substrate 11, in which case an adhesive-coated member can be formed by hardening. The substrate 11 and the member are not limited. The substrate 11 may be in the form of a sheet. When transferring after hardening, the surface on which the adhesive 14 is formed on the substrate 11 may be peeled off.

[0206] The base material 11 may be formed from metal, resin, glass, or a composite material thereof. Examples of metals include aluminum and stainless steel. Examples of resins include polyester such as polyethylene terephthalate and polyethylene naphthalate, acetate resin, polyethersulfone, polycarbonate, polyamide, polyimide, polyolefin, (meth)acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl alcohol, polyarylate, and polyphenylene sulfide. The component that is the object to be attached may also have at least the transfer surface or forming surface of the adhesive 14 formed from one of the materials exemplified above. However, the materials constituting the base material 11 and the object to be attached are not limited to the examples above.

[0207] For the release treatment, various release agents can be used, such as silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, fatty acid amide-based release agents, and silica powder.

[0208] An example where the base material 11 is in sheet form is shown in Figure 2. The method in Figure 2 is suitable for forming a sheet-like adhesive B. In the method in Figure 2, a coating layer 32 containing the adhesive composition A formed on the base material sheet 31 is irradiated with light 34. The coating layer 32 hardens upon irradiation with light 34 and becomes a sheet-like adhesive B (reference numeral 1). In the formed adhesive 1, the surface opposite to the side facing the base material sheet 31 is exposed to the outside. Other layers can be laminated onto the exposed surface of the adhesive 1. The other layers may be laminated directly or through further layers. The exposed adhesive 1 surface may be attached to or transferred onto a target object.

[0209] The sheet-like adhesive B may be formed by the method shown in Figure 3. In the method shown in Figure 3, a first laminate 30, which includes a base sheet 31, a coating layer 32 containing adhesive composition A, and a release liner 33 in that order, is irradiated with light 34. The coating layer 32 hardens upon irradiation with light 34 and becomes a sheet-like adhesive B (reference numeral 1). In the example shown in Figure 3, light 34 is irradiated from the side of the base sheet 31. However, light 34 may be irradiated from the side of the release liner 33, or from both the base sheet 31 and the release liner 33. When irradiated from both sides, the irradiation of light 34 from each side may be simultaneous. Furthermore, the wavelength of the light 34 irradiated from the side of the base sheet 31 and the wavelength of the light 34 irradiated from the side of the release liner 33 may be the same or different from each other.

[0210] The formed adhesive 1 is sandwiched between the base sheet 31 and the release liner 33 until the release liner 33 is peeled off, and constitutes a part of the second laminate 37. By peeling the release liner 33 off the second laminate 37, a third laminate 35 containing the base sheet 31 and the adhesive 1 is obtained. In the third laminate 35, the surface of the adhesive 1 is exposed to the outside. Other layers can be laminated onto the exposed surface of the adhesive 1. The other layers may be laminated directly or through further layers. The exposed surface of the adhesive 1 may be attached to or transferred onto a target object.

[0211] Examples of light 13 and 34 are visible light and ultraviolet light. Light 13 and 34 are preferably visible light or ultraviolet light having a wavelength shorter than 450 nm, and more preferably ultraviolet light. Light 13 and 34 may include light in the range of 380 nm ± 30 nm, and may also include light in the range of 380 nm ± 20 nm, light in the range of 380 nm ± 10 nm, light in the range of 380 nm ± 5 nm, and even light with a wavelength of 380 nm.

[0212] Lights 13 and 34 may include light with wavelengths in the same region as the absorption wavelength of the photoinitiator contained in adhesive composition A. Lights 13 and 34 may be irradiated with short-wavelength light of 300 nm or less filtered out. The light source for lights 13 and 34 (reference numeral 38 in Figure 3) is, for example, a light irradiation device equipped with an ultraviolet irradiation lamp. Examples of ultraviolet irradiation lamps include ultraviolet LEDs, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, microwave-excited mercury lamps, black light lamps, chemical lamps, germicidal lamps, low-pressure discharge mercury lamps, and excimer lasers. Two or more ultraviolet irradiation lamps may be combined. The light source for lights 13 and 34 may also be equipped with a black light.

[0213] The illuminance of the light 13 and 34 irradiated onto the coated object 12 and the coated layer 32 is, for example, 1.0 to 30 mW / cm². 2 The illuminance is 1.5 mW / cm². 2 Above, 2.0mW / cm 2 Furthermore, 2.5 mW / cm² 2 The above may also be acceptable. The upper limit of illuminance is 25 mW / cm². 2 Below, 20mW / cm 2 Below, 15mW / cm 2 Below, 10mW / cm 2 Below, 7.5mW / cm 2 Furthermore, 5 mW / cm² 2 The following is also acceptable.

[0214] The duration of irradiation with light 13,34 may be, for example, 10 seconds to 2000 seconds, and may be 60 seconds or more, 100 seconds or more, 250 seconds or more, 300 seconds or more, 400 seconds or more, or even 500 seconds or more. There is no upper limit to the duration; for example, it may be 5 hours or less, and may be 4 hours or less, 3 hours or less, 2 hours or less, 1 hour or less, 3000 seconds or less, 2500 seconds or less, 2000 seconds or less, 1500 seconds or less, 1250 seconds or less, 1100 seconds or less, or even 1000 seconds or less. Irradiation with light may be continuous or intermittent.

[0215] The integrated light intensity of the irradiated light 13 and 34 is, for example, 25 mJ / cm². 2 That is all, 100 mJ / cm 2Above, 500mJ / cm 2 Above, 1000mJ / cm 2 Above, 2000mJ / cm 2 Above, 2500mJ / cm 2 Above, 3000mJ / cm 2 Above, 4000mJ / cm 2 Furthermore, 5000 mJ / cm 2 The above is also acceptable. The upper limit of the integrated light intensity is not particularly limited, for example, 30,000 mJ / cm². 2 The following is true: 25,000 mJ / cm² 2 Below, 20000mJ / cm 2 Below, 15000mJ / cm 2 Below, 10000mJ / cm 2 Below, 5000mJ / cm 2 The following, and even 3000 mJ / cm 2 The following is also acceptable.

[0216] The light may be irradiated onto the coated object 12 and the coated layer 32 in multiple stages. The illuminance and / or integrated light quantity at each stage may be the same or different from each other. Also, the light sources at each stage may be the same or different from each other.

[0217] Light may be irradiated onto the coated object 12 or coated layer 32 having a dissolved oxygen concentration of 0.1 volume% or less, 0.05 volume% or less, or even 0.01 volume% or less. This method is particularly suitable for suppressing curing inhibition by oxygen. To reduce the dissolved oxygen concentration in the coated object 12 and coated layer 32, bubbling with an inert gas, such as nitrogen, may be performed on the adhesive composition A.

[0218] Resin sheets may be used for the base sheet 31 and the release liner 33. Examples of resins that make up the resin sheet are the same as examples of resins that can make up the base material 11. The surfaces of the base sheet 31 and the release liner 33 that come into contact with the coating layer 32 may be treated with a release agent.

[0219] At least a portion of the process for forming adhesive B may be carried out in an inert gas atmosphere, such as a nitrogen purging atmosphere. Alternatively, a portion of the process for forming adhesive B may be carried out in an atmosphere with a reduced oxygen concentration compared to air, such as an atmosphere with an oxygen concentration of 1 vol% or less, 0.5 vol% or less, 0.1 vol% or less, 0.08 vol% or less, 0.06 vol% or less, 0.05 vol% or less, 0.04 vol% or less, 0.03 vol% or less, 0.02 vol% or less, 0.01 vol% or less, or even less than 0.01 vol%. This method is particularly suitable for suppressing curing inhibition by oxygen.

[0220] At least a portion of the process for forming adhesive B may be carried out under atmospheric pressure. Alternatively, a portion of the process for forming adhesive B may be carried out in a reduced pressure atmosphere, such as a vacuum atmosphere.

[0221] In forming adhesive B, steps other than those described above may be performed.

[0222] In the manufacturing method of this embodiment, heating during the curing of adhesive composition A to form adhesive B can be omitted. For example, in the manufacturing method of this embodiment, adhesive composition A may be kept in an environment below 50°C while it is curing. However, heating may be performed, for example, the coated object 12, the coated layer 32, or adhesive B may be heated after irradiation with light 13, 34. Alternatively, for example, the coated object 12, the coated layer 32, or adhesive B may be microwave-dried after irradiation with light 12, 34.

[0223] ≪≪3. Adhesive-Coated Member≫≫ The adhesive-coated member according to this embodiment comprises an adhesive B and a member. The adhesive B is typically in contact with the member. The adhesive B may be disposed on at least a portion of the surface of the member. The adhesive B may also be contained inside the member. The type and shape of the member are not particularly limited. The member may be an optical member, in which case the adhesive-coated member according to this embodiment is an adhesive-coated optical member.

[0224] The component may be a film or a sheet. The component may be formed from resin, metal, glass, or a composite material thereof. The component may be a release liner.

[0225] Examples of the optical member include a polarizing film, a retardation film, a protective film, and an antireflection film. The optical member may be various optical members that an image display device may include.

[0226] Depending on the application, the member with an adhesive according to the present embodiment can take various forms.

[0227] ≪4. Cured body≫ <4-1. Cured body> The cured body according to the present embodiment is formed from the adhesive B. Specifically, the cured body is formed by further curing the adhesive B in a high-temperature environment. The cured body typically contains a material derived from the adhesive composition A. Further, the cured body typically contains a material derived from the adhesive B.

[0228] The tensile storage modulus E' of the cured body at 25°C is, for example, 5.0×10 6 Pa or more, and may be 1.0×10 7 Pa or more, 5.0×10 7 Pa or more, 1.0×10 8 Pa or more, and may even be 3.0×10 8 Pa or more, 5.0×10 8 Pa or more, 8.0×10 8 Pa or more, 1.0×10 9 Pa or more, 1.5×10 9 Pa or more, and further may be 2.0×10 9 Pa or more. The upper limit of the tensile storage modulus E' of the cured body is, for example, 1.0×10 11 Pa or less, and may be 1.0×10 10 Pa or less. Note that the tensile storage modulus E' of the adhesive B before curing at 25°C is typically less than 5.0×10 6 Pa.

[0229] The tensile storage modulus E' of a hardened material at 25°C can be measured by the following method. First, a measurement sample made of the hardened material is prepared. The measurement sample measures 300 mm in length, 10 mm in width, and 25 μm in thickness. Next, dynamic viscoelasticity measurement is performed on the measurement sample under the following measurement conditions. For dynamic viscoelasticity measurement, for example, an RSA-G2 manufactured by TA Instruments can be used. From the results of the dynamic viscoelasticity measurement, the tensile storage modulus of the measurement sample at 25°C is determined, and the obtained value is considered to be the tensile storage modulus E' of the hardened material. Note that the tensile storage modulus E' can be converted to the shear storage modulus G' based on the relationship E' = 3G', assuming a Poisson's ratio of 0.5. Measurement conditions: Deformation mode: Tensile Measurement frequency: 1 Hz Temperature range: 20°C to 150°C Heating rate: 5°C / min

[0230] The refractive index of the cured material is, for example, 1.40 or higher, and may also be 1.43 or higher, 1.45 or higher, 1.48 or higher, 1.50 or higher, 1.51 or higher, 1.52 or higher, 1.53 or higher, 1.54 or higher, 1.55 or higher, 1.56 or higher, 1.57 or higher, 1.58 or higher, 1.59 or higher, 1.60 or higher, 1.61 or higher, 1.62 or higher, 1.63 or higher, 1.64 or higher, and even 1.65 or higher. The upper limit of the refractive index is, for example, 1.70 or lower, and may also be 1.69 or lower, 1.68 or lower, 1.67 or lower, 1.66 or lower, and even 1.65 or lower. The refractive index of the cured material can be measured for adhesive B by the method described above.

[0231] The shape of the cured body is not limited. The cured body may be in the form of a sheet, an amorphous body, or a bulk body with a predetermined shape. The cured body may have any shape depending on the application.

[0232] <4-2. Method for Manufacturing a Cured Body> The cured body according to this embodiment can be formed by further curing the adhesive B in a high-temperature environment. The adhesive B may be heated while it is attached to the adherend. The temperature of the high-temperature environment can be appropriately set according to the composition of the adhesive B (especially the type and content of the thermal initiator), and may be, for example, 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, 100°C or higher, 110°C or higher, and even 120°C or higher. The upper limit of the temperature of the high-temperature environment may be, for example, 200°C or lower, 180°C or lower, and even 160°C or lower. The heating time for the adhesive B is, for example, 1 minute to 5 hours. The heating of the adhesive B may be carried out while a load is applied in the direction in which the adhesive B and the adherend are in contact.

[0233] Adhesive B suitable for forming a cured body may contain a thermal initiator and a crosslinking agent (more specifically, a polyfunctional monomer that does not have an ethylenically unsaturated group). When adhesive B contains a thermal acid generator as a thermal initiator, acid is generated from the thermal acid generator in a high-temperature environment, and this acid can cause a reaction between the polymer of monomer component M and the crosslinking agent to proceed. As this reaction progresses, adhesive B hardens and a cured body is formed.

[0234] If the thermal initiator contains a compound that reacts with the monomer component M polymer and the crosslinking agent in a high-temperature environment, heating the adhesive B will cause the reaction between the monomer component M polymer, the crosslinking agent, and the thermal initiator to proceed. In other words, the monomer component M polymer and the crosslinking agent react via the thermal initiator. As a result, the adhesive B hardens and a cured body is formed.

[0235] <4-3. Cured Sheet> The cured body according to this embodiment may be a sheet-shaped cured body, in other words, a cured sheet.

[0236] Cured sheets tend to be able to join components with high adhesive strength. For example, a cured sheet may have an adhesive strength of 5.0 MPa or higher, as determined by the following test. Test: Two pieces of glass are bonded together via an adhesive sheet. The adhesive sheet is cured to form a cured sheet. Under an atmosphere of 23°C and 50% RH, the two pieces of glass are pulled in a direction away from each other at a tensile speed of 10 mm / min. The adhesive strength can be determined based on the maximum stress at this time.

[0237] The adhesive strength of the cured sheet can be measured in detail by the following method. First, the adhesive sheet described above is cut to a size of 10 mm x 10 mm, and one surface of the adhesive sheet is bonded to the first glass. Next, the other surface of the adhesive sheet is bonded to the second glass. This yields a measurement sample in which the first glass and the second glass are bonded together via the adhesive sheet.

[0238] Next, the adhesive sheet is hardened by heating the sample to form a hardened sheet. The heating conditions for the sample are not particularly limited, as long as a hardened sheet is formed. For example, the sample may be heated in a 100°C dryer for 2 hours with a 1 kg weight placed on top.

[0239] Next, the sample for measurement is attached to the aluminum block using an adhesive (for example, Cemedyne High Super 30). After the adhesive has cured, the sample for measurement is placed in a commercially available tensile testing machine. Under an atmosphere of 23°C and 50% RH, the first and second glass pieces are pulled in a direction that separates them from each other at a tensile speed of 10 mm / min. The adhesive strength can be determined based on the maximum stress at this time.

[0240] The adhesive strength of the cured sheet may be 3.0 MPa or higher, 4.0 MPa or higher, 5.0 MPa or higher, 6.0 MPa or higher, 7.0 MPa or higher, 8.0 MPa or higher, 9.0 MPa or higher, 10.0 MPa or higher, or even 11.0 MPa or higher. The upper limit of the adhesive strength of the cured sheet may be, for example, 30.0 MPa or lower, but may also be 25.0 MPa or lower, 20.0 MPa or lower, or even 15.0 MPa or lower.

[0241] The thickness of the cured sheet is, for example, 100 μm or less, and may be 70 μm or less, 50 μm or less, 35 μm or less, 30 μm or less, 25 μm or less, or even 15 μm or less. The lower limit of the thickness of the cured sheet is, for example, 1 μm or more, and may be 3 μm or more, 5 μm or more, 8 μm or more, or even 12 μm or more. In some cases, the thickness of the cured sheet may be 15 μm or more, and may be 20 μm or more, 30 μm or more, 35 μm or more, or even 40 μm or more.

[0242] The method for manufacturing a cured sheet according to this embodiment can be described by referring to the explanation in section 4-2. Method for manufacturing a cured body.

[0243] ≪5. Members Equipped with a Cured Body≫ Members equipped with a cured body according to this embodiment are equipped with a cured body according to this embodiment. The cured body is typically located on the surface and / or inside the member. The type and shape of the member are not particularly limited. The member may be an optical member. Examples of optical members are as described above. Depending on the application, members equipped with a cured body according to this embodiment can take various forms.

[0244] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way to these examples.

[0245] <<Preparation of Adhesive Composition>> <Preparation of Monomer Syrup> [Monomer Syrup A1] 100 parts by weight of 2-ethylhexyl acrylate (2EHA) and 0.05 parts by weight of 1-hydroxycyclohexyl phenyl ketone (Omnirad 184, manufactured by IGM Resins) as a photoinitiator were placed in a four-necked flask. Next, monomer syrup A1 was obtained by partially polymerizing 2EHA by irradiating the liquid in the flask with ultraviolet light under a nitrogen atmosphere. Monomer syrup A1 contains partially polymerized 2EHA. The ultraviolet irradiation was carried out until the viscosity of the liquid in the flask (measurement conditions: BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30°C) was approximately 15 Pa·s.

[0246] <Preparation of Adhesive Composition> [Adhesive Composition B1] 100 parts by weight of monomer syrup A1, 0.2 parts by weight of 1,9-nonanediol diacrylate (NDDA) as a crosslinking agent, 0.5 parts by weight of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Omnirad 819, manufactured by IGM Resins) as a photoinitiator, and 20 parts by weight of a 2EHA dispersion of carbon black (solid content 15% by weight) as a coloring agent were added to obtain adhesive composition B1. No organic solvents were added to adhesive composition B1.

[0247] [Adhesive Composition B2] Adhesive composition B2 was obtained in the same manner as adhesive composition B1, except that the amount of coloring agent was changed to 30 parts by weight.

[0248] [Adhesive Composition B3] Adhesive composition B3 was obtained in the same manner as adhesive composition B1, except that the amount of coloring agent was changed to 40 parts by weight.

[0249] [Adhesive Composition B4] 100 parts by weight of monomer syrup A1 and 50 parts by weight of acryloylmorpholine (ACMO) as a monomer were mixed. Next, 0.2 parts by weight of NDDA as a crosslinking agent, 0.5 parts by weight of Omnirad 819 as a photoinitiator, and 40 parts by weight of a 2EHA dispersion of carbon black (solid content 15% by weight) as a coloring agent were added to the resulting mixture to obtain adhesive composition B4. No organic solvents were added to adhesive composition B4.

[0250] [Adhesive Composition B5] Adhesive composition B5 was obtained in the same manner as adhesive composition B1, except that 20 parts by weight of a dispersion of carbon black phenoxybenzyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Light Acrylate POB-A"; hereinafter referred to as "POB-A") (solid content 15% by weight) was used as a coloring agent.

[0251] [Adhesive Composition B6] Adhesive composition B6 was obtained in the same manner as adhesive composition B5, except that the amount of coloring agent was changed to 30 parts by weight.

[0252] [Adhesive Composition B7] Adhesive composition B7 was obtained in the same manner as adhesive composition B5, except that the amount of coloring agent was changed to 40 parts by weight.

[0253] [Adhesive Composition B8] Adhesive composition B8 was obtained in the same manner as adhesive composition B1, except that the amount of colorant was changed to 75 parts by weight and the amount of NDDA was changed to 0.3 parts by weight.

[0254] [Adhesive Composition B9] 100 parts by weight of monomer syrup A1 and 5 parts by weight of acrylic acid (AA) as a monomer were mixed. Next, 0.3 parts by weight of NDDA as a crosslinking agent, 0.5 parts by weight of Omnirad 819 as a photoinitiator, and 40 parts by weight of a 2EHA dispersion of carbon black (solid content 15% by weight) as a coloring agent were added to the resulting mixture to obtain adhesive composition B9. No organic solvents were added to adhesive composition B9.

[0255] [Adhesive Composition B10] 100 parts by weight of monomer syrup A1 and 5 parts by weight of N-vinylpyrrolidone (NVP) as a monomer were mixed. Next, 0.3 parts by weight of NDDA as a crosslinking agent, 0.5 parts by weight of Omnirad 819 as a photoinitiator, and 40 parts by weight of a 2EHA dispersion of carbon black (solid content 15% by weight) as a coloring agent were added to the resulting mixture to obtain adhesive composition B10. No organic solvents were added to adhesive composition B10.

[0256] [Adhesive Composition B11] Adhesive composition B11 was obtained in the same manner as adhesive composition B1, except that the amount of colorant was changed to 30 parts by weight, the amount of NDDA was changed to 0.3 parts by weight, and the photoinitiator was changed to 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad 651, manufactured by IGM Resins).

[0257] [Adhesive Composition B12] 80 parts by weight of monomer syrup A1 and 20 parts by weight of 2EHA as monomer were mixed. Next, 0.1 parts by weight of NDDA as a crosslinking agent, 0.5 parts by weight of Omnirad 819 as a photoinitiator, 1 part by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal initiator, and 50 parts by weight of an ethyl acetate dispersion of carbon black (solids content 22% by weight) as a coloring agent were added to the resulting mixture to obtain adhesive composition B12. The content of organic solvent in adhesive composition B12 was 25.7% by weight.

[0258] [Adhesive Composition B13] Adhesive composition B13 was obtained in the same manner as adhesive composition B12, except that AIBN was not included. The content of organic solvent in adhesive composition B13 was 25.9% by weight.

[0259] The compositions of each adhesive composition prepared are summarized in Table 1 below.

[0260]

[0261] The abbreviations in Table 1 are as follows: (Monomers) ACMO: Acrylicylmorpholine 2EHA: 2-Ethylhexyl acrylate AA: Acrylic acid NVP: N-Vinylpyrrolidone POB-A: Phenoxybenzyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Light Acrylate POB-A") (Crosslinking agent) NDDA: 1,9-Nonanediol diacrylate (Photoinitiator) Omnirad819: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (manufactured by IGM Resins, trade name "Omnirad819") Omnirad651: 2,2-Dimethoxy-1,2-Diphenylethane-1-one (manufactured by IGM Resins, trade name "Omnirad651") (Thermal initiator) AIBN: 2,2'-azobisisobutyronitrile (azo initiator)

[0262] <Preparation of Adhesive> [Preparation of Release Liner] A silicone-based release agent composition was obtained by mixing 30 parts by weight of addition-curing silicone (LTC761 containing a hexenyl group-containing polyorganosiloxane, 30% by weight toluene solution, manufactured by Toray Dow Corning), 0.9 parts by weight of release control agent (BY24-850 containing an unreactive silicone resin, manufactured by Toray Dow Corning), 2 parts by weight of curing catalyst (SRX212 containing a platinum catalyst, manufactured by Toray Dow Corning), and a toluene / hexane mixed solvent (volume ratio 1:1) as a diluent. The concentration of silicone solids in the release agent composition was 1.0% by weight. Next, the release agent composition was applied to one side of a liner substrate (Lumirror XD500P, a polyester film, 75 μm thick) using a wire bar, and heated at 130°C for 1 minute to produce a release liner with a release layer (60 nm thick) on one side.

[0263] [Preparation of Adhesive] (Example 1) Adhesive composition B1 was applied to one side of a base sheet (PET separator, manufactured by Mitsubishi Plastics, MRF38) using an applicator to form a coating layer. Next, the above-mentioned release liner was placed on the formed coating layer to obtain a first laminate. The release liner was positioned so that the release layer was in contact with the coating layer. Next, from the side of the base sheet in the first laminate, an illuminance of 2.5 mW / cm was applied. 2 and integrated light intensity of 2400 mJ / cm 2 Under these conditions, ultraviolet light was irradiated from a black light source. No ultraviolet light was irradiated from the side of the release liner. As a result, the coating layer was cured, and the adhesive of Example 1 (in the form of a sheet with a thickness of 25 μm) was obtained sandwiched between the base sheet and the release liner. The illuminance of the light was measured using an illuminance meter (U0-T36T2, manufactured by Topcon Techno House Co., Ltd.) near the surface on which the ultraviolet light was incident on the base sheet.

[0264] (Examples 2-11) Adhesives for Examples 2-11 (all in the form of sheets with a thickness of 25 μm) were obtained in the same manner as in Example 1, except that the adhesive compositions shown in Table 2A below were used instead of adhesive composition B1.

[0265] (Comparative Examples 1-2) An attempt was made to produce a sheet-like adhesive with a thickness of 25 μm in the same manner as in Example 1, except that the adhesive compositions shown in Table 2B below were used instead of the adhesive composition B1. However, for all of the adhesive compositions, curing was insufficient, and a sheet-like adhesive could not be produced.

[0266]

[0267]

[0268] <Evaluation of Adhesive> For each of the produced adhesives, the following characteristics were evaluated.

[0269] [Polymerization Rate] The polymerization rate of the monomer component in the adhesive was calculated from the change in the weight of the adhesive before and after heat drying at 130 °C for 2 hours. Specifically, the weight of the adhesive immediately after peeling from the base sheet was designated as W A (weight before drying), and the weight of the adhesive at the time when it was cooled at room temperature (23 °C) for about 20 minutes after the above heating was designated as W B (weight after drying). The polymerization rate (%) was determined by the formula: Polymerization rate (%) = W B / W A × 100. However, for the adhesives of Examples 5-7 formed from the adhesive compositions B5-B7 containing POB-A as the monomer component, taking into account the high boiling point of POB-A, it was calculated from the change in the weight of the adhesive before and after heat drying at 130 °C for 2 hours under vacuum.

[0270] [Refractive Index] The refractive index of the adhesive was evaluated as follows. The adhesive to be evaluated was pasted so as to uniformly cover the prism of a digital refractometer (manufactured by Atago Co., Ltd., digital refractometer RX-9000α). The pasting was carried out so that no exposed portion would occur on the prism and no bubbles would occur between the adhesive and the prism. Next, the refractive index of the adhesive (measured value at 25 °C, in other words, nD25) was determined by the reflection method. In order to improve the measurement accuracy, the measurement was carried out after 15 minutes had elapsed in a 25 °C environment after the adhesive was pasted. Also, seven measurements were carried out with the adhesive pasted, and the refractive index was specified as the average value of five measured values after removing the maximum value and the minimum value.

[0271] [Total Light Transmittance] The total light transmittance of the adhesive was evaluated as follows: An alkali-free glass plate (thickness 0.7-0.8 mm, total light transmittance 92%, chromaticity b) was placed on one surface of the sheet-like adhesive exposed by peeling off the base sheet and release liner. * 0.10) was bonded to the other surface with a cycloolefin (COP) film to obtain a test specimen in which the adhesive was sandwiched between alkali-free glass and cycloolefin film.

[0272] Next, the test specimens were placed in a pressurized degassing device (autoclave) and autoclaved under conditions of 50°C, 0.5 MPa pressure, and for 30 minutes. After treatment, the test specimens were left for 24 hours in an environment of 23°C and 50% relative humidity. Then, under the measurement environment of 23°C, the total light transmittance of the test specimens for light with wavelengths from 300 nm to 800 nm was measured using a UV-Vis-Near-Infrared spectrophotometer (Hitachi High-Tech, UH4150). For the measurement of total light transmittance, reference data (blank data) measured without the test specimens in the UV-Vis-Near-Infrared spectrophotometer's measurement chamber was used as a reference.

[0273] [L * a * b * ] Adhesive L * Value, a * value, b * The values ​​were evaluated as follows: Test specimens, prepared using the same autoclave treatment method as those used for the evaluation of total light transmittance, were left for 24 hours in an environment of 23°C and 50% relative humidity. The transmission spectrum of the specimens for light with wavelengths from 300 nm to 800 nm was then measured using a UV-Vis-Near-Infrared spectrophotometer (Hitachi High-Tech, UH4150). Measurements were performed at 23°C. Next, the lightness L was calculated from the obtained spectral data using a color calculation program (Hitachi High-Tech, UV Solutions). * and chromaticity a * The absolute value of (|a) * |), b * The absolute value of (| b) * The chromaticity a was calculated. * , b *For the measurement, reference data (blank data) measured without placing the test specimen in the measurement chamber of the ultraviolet-visible-near-infrared spectrophotometer was used as the basis.

[0274] [Adhesive Strength] The adhesive strength of the adhesive was evaluated using the method described above. For evaluation, an untreated PET film (Toray Industries, Ltd., Lumir S10, 25 μm thick) was used as the base sheet.

[0275] The evaluation results for the adhesive are shown in Table 3 below.

[0276]

[0277] As shown in Table 3, the adhesive compositions in the comparative examples did not cure sufficiently, but the adhesive compositions in the examples made it possible to produce sheet-like adhesives.

[0278] The photocurable adhesive composition of the present invention can be used in the same applications as conventional photocurable adhesive compositions. Examples of applications include adhesives and adhesive sheets for optical applications, optical laminates, or image display devices. However, applications are not limited to the above examples.

Claims

1. A photocurable adhesive composition comprising a monomer component M, a photoinitiator, and a colorant, wherein the content of an organic solvent is less than 1% by weight.

2. The photocurable adhesive composition according to claim 1, wherein the coloring agent is a black coloring agent.

3. The photocurable adhesive composition according to claim 1, wherein the coloring agent comprises a carbon compound.

4. The photocurable adhesive composition according to claim 1, wherein the content of (meth)acrylic monomer in the monomer component M is 50% by weight or more.

5. The photocurable adhesive composition according to claim 1, wherein the monomer component M comprises monomer a having a double bond-containing ring.

6. The photocurable adhesive composition according to claim 5, wherein the double bond-containing ring is an aromatic ring.

7. The photocurable adhesive composition according to claim 5, wherein monomer a has two or more double bond-containing rings in its side chain.

8. The photocurable adhesive composition according to claim 7, wherein monomer a has a side chain structure in which a first double bond-containing ring and a second double bond-containing ring, both contained in the two or more double bond-containing rings, are linked via a linking group.

9. The photocurable adhesive composition according to claim 5, wherein the monomer a is phenoxybenzyl acrylate.

10. The photocurable adhesive composition according to claim 1, comprising the photoinitiator having the chemical structure shown in formula (1) in its molecule. However, the "*" in formula (1) indicates a bonding site with another atom.

11. The photocurable adhesive composition according to claim 1, wherein the amount of the photoinitiator in the photocurable adhesive composition is 0.01 to 10 parts by weight per 100 parts by weight of the monomer component M.

12. An adhesive formed from the photocurable adhesive composition according to any one of claims 1 to 11.

13. The adhesive according to claim 12, wherein the polymerization rate of the monomer component M is 98.0% or more.

14. CIE1976(L) as defined in JIS Z8781-4:2013 * , a * , b * ) L in the color space * The adhesive according to claim 12, which is displayed by and has a brightness of 60.0 or less.

15. a of the aforementioned color space * The absolute value of has a chromaticity of 10.0 or less, and the b of the color space * The adhesive according to claim 14, having a chromaticity of 10.0 or less when expressed by the absolute value of .

16. The adhesive according to claim 12, having a refractive index of 1.50 or higher.

17. The adhesive according to claim 12, having a total light transmittance of less than 5%.

18. An adhesive-coated member comprising the adhesive and member described in claim 12.

19. The adhesive-coated optical component according to claim 18.

20. A method for producing an adhesive, comprising curing the photocurable adhesive composition according to any one of claims 1 to 11 by irradiating it with light.

21. A cured body formed from the adhesive described in claim 12.

22. A member comprising the cured body described in claim 21.

23. The member according to claim 22, which is an optical member.

24. A method for producing a cured body, comprising further curing the adhesive described in claim 12 in a high-temperature environment.

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