Adhesive composition, adhesive sheet, adhesive sheet with release film, laminate for image display device, image display device, and adhesive sheet for organic el display device

Abstract

Provided is an adhesive composition which can be cured by an energy ray on a longer wavelength side and which has few photodecomposition products. A pressure-sensitive adhesive composition containing a (meth) acrylic polymer (A) and a photoinitiator (B), or containing a (meth) acrylic polymer (A), a photoinitiator (B) and an ultraviolet absorber (C), the photoinitiator (B) including a photoinitiator (b1) having a structure represented by *-CO-COOR1 (wherein R1 represents a hydrogen atom or a hydrogen atom, and R2 represents a hydrogen atom or a hydrogen atom; r1 is a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted cycloalkyl group with 3 to 20 carbon atoms or a substituted or unsubstituted heterocyclic alkyl group with 2 to 20 carbon atoms. And * represents a linking bond), and the molar absorption coefficient at a wavelength of 405 nm is 30 (L / mol.cm) or more.

Description

Technical Field

[0001] The present invention relates to an adhesive composition and an adhesive sheet using the same, an adhesive sheet with a release film, a laminate for an image display device, an image display device, and an adhesive sheet for an organic EL display device.

[0002] This application claims priority based on Special Application No. 2022-192169 and Special Application No. 2022-192160 filed in Japan on November 30, 2022, and Special Application No. 2023-133424 filed in Japan on August 18, 2023, the contents of which are incorporated herein by reference. Background Art

[0003] In recent years, in order to improve the visibility of image display devices, the following operations have been performed: filling the gap between an image display panel such as a liquid crystal display (LCD), a plasma display (PDP) or an electroluminescent display (ELD) and an optical component such as a protective panel and a touch panel component arranged on the front surface side (visible side) thereof with a resin such as an adhesive or bonding agent to suppress reflection of incident light and emitted light from a displayed image at the interface of an air layer.

[0004] For example, in Patent Document 1, as a method for manufacturing a laminated body for an image display device having a structure in which components of an image display device are stacked on at least one side of a transparent double-sided adhesive sheet, the following method is disclosed: after an adhesive sheet that has been once cross-linked using ultraviolet rays is adhered to the components of the image display device, the adhesive sheet is irradiated with ultraviolet rays through the components of the image display device to cause secondary curing.

[0005] Patent Document 2 discloses a pressure-sensitive adhesive sheet containing a (meth)acrylic copolymer having an ultraviolet crosslinkable moiety as a pressure-sensitive adhesive sheet useful for display and touch panels.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 4971529

[0009] Patent Document 2: Japanese Patent No. 6062740 Summary of the invention

[0010] Problem that the invention aims to solve

[0011] Most adhesive sheets that form a crosslinked structure by ultraviolet irradiation contain a photoinitiator that generates free radicals by ultraviolet irradiation. However, in recent years, from the perspective of energy saving and component protection, there has been an increasing demand for adhesive sheets that are photocured with lower energy and high efficiency, that is, adhesive sheets that are cured using energy rays on the longer wavelength side (e.g., active energy rays with a wavelength longer than 380 nm), especially adhesive sheets that are cured using visible light.

[0012] Furthermore, in recent years, as image display devices have been required to be more power-saving, lighter, and thinner, organic EL has become more and more popular as image display panels, replacing conventional liquid crystal panels.

[0013] In image display devices such as organic EL display devices, components in the image display device may be degraded by ultraviolet light. In order to suppress the degradation caused by ultraviolet light, there is a strong demand for a pressure-sensitive adhesive sheet that cures with visible light.

[0014] In addition, in an adhesive sheet that is bonded to an adherend such as a component constituting an image display device and then irradiated with light through the component to perform secondary curing, if the intervening component has ultraviolet light absorptivity, there is a problem that the light required for curing does not reach the adhesive sheet. The adhesive sheet used in an image display device of this structure needs to be made into an adhesive sheet that is cured using visible light.

[0015] Furthermore, in image display devices such as organic EL display devices, there is an increasing demand for pressure-sensitive adhesive sheets containing ultraviolet absorbers in order to suppress degradation due to incident ultraviolet light.

[0016] Most adhesive sheets that form a crosslinked structure upon ultraviolet irradiation contain a photoinitiator that generates free radicals upon ultraviolet irradiation. However, when an ultraviolet absorber is contained in an adhesive sheet, there is a problem that the ultraviolet rays are blocked and the curing reaction cannot proceed sufficiently.

[0017] Due to these circumstances, photocurable adhesive sheets using photoinitiators that absorb in the ultraviolet region and visible light region with longer wavelengths, α-aminoacetophenone-based or acylphosphine oxide-based photoinitiators have been developed. However, these cleavage-type photoinitiators generate outgassing such as benzaldehyde as a photodecomposition product, and therefore are not preferred from an environmental perspective.

[0018] On the other hand, hydrogen abstraction type photoinitiators such as thioxanthone and anthraquinone that do not generate photodecomposition products during the reaction have absorption in the ultraviolet region and visible light region in the long wavelength region, but there is a problem of coloration, especially yellowing, caused by the photoinitiator in the cured product. Therefore, the amount added is limited, especially in applications requiring colorlessness and transparency, and sufficient curing sensitivity cannot be obtained.

[0019] An object of the present invention is to provide an adhesive composition, an adhesive sheet, a laminate for an image display device using the above-mentioned adhesive sheet, an image display device, and an adhesive sheet for an organic EL display device, which can be cured by energy rays on the longer wavelength side, such as active energy rays with a wavelength longer than 380 nm, especially active energy rays of 405 nm, and has a small amount of photodecomposition products.

[0020] Another object of the present invention is to provide an adhesive composition that has ultraviolet absorption and can be cured using active energy rays and has a small amount of photodecomposition products, an adhesive sheet, an adhesive sheet with a release film using the above-mentioned adhesive sheet, a laminate for an image display device, an image display device, and an adhesive sheet for an organic EL display device.

[0021] Solutions for solving problems

[0022] One embodiment of the present invention includes the following aspects.

[0023] [1] An adhesive composition comprising a (meth)acrylic polymer (A) and a photoinitiator (B), wherein the photoinitiator (B) comprises a photoinitiator (b1), and the photoinitiator (b1) has a glyoxylate structure represented by the following formula 1 and has a molar absorption coefficient of 30 (L / mol·cm) or more at a wavelength of 405 nm.

[0024]

[0025] (In the above formula 1, R 1 is substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 3 ~C 20 Cycloalkyl or substituted or unsubstituted C 2 ~C 20 Heterocycloalkyl. * indicates a connecting bond. )

[0026] [2] An adhesive composition comprising a (meth)acrylic polymer (A), a photoinitiator (B) and an ultraviolet absorber (C),

[0027] The photoinitiator (B) includes a photoinitiator (b1), wherein the photoinitiator (b1) has a glyoxylate structure represented by the following formula 1 and has a molar absorption coefficient of 30 (L / mol·cm) or more at a wavelength of 405 nm.

[0028]

[0029] (In the above formula 1, R 1 is substituted or unsubstituted C 1 ~C 20Alkyl, substituted or unsubstituted C 3 ~C 20 Cycloalkyl or substituted or unsubstituted C 2 ~C 20 Heterocycloalkyl. * indicates a connecting bond. )

[0030] [3] The adhesive composition according to [1] or [2], wherein the photoinitiator (b1) is a compound including a biphenyl structure to which the connecting bond * in Formula 1 is bonded.

[0031] [4] The adhesive composition according to [1] or [2], wherein the photoinitiator (b1) is a compound including a thiobiphenyl structure to which the linking bond * in Formula 1 is bonded.

[0032] [5] The adhesive composition according to any one of [1] to [4], wherein the photoinitiator (b1) is a compound having two or more radical-generating groups in the molecule.

[0033] [6] The adhesive composition according to any one of [1] to [5], further comprising a polyfunctional (meth)acrylate (D).

[0034] [7] The adhesive composition according to [6], wherein the content of the polyfunctional (meth)acrylate (D) is 0.1 parts by mass or more and 20 parts by mass or less based on 100 parts by mass of the (meth)acrylic polymer (A).

[0035] [8] The adhesive composition according to any one of [1] to [7], wherein the (meth)acrylic polymer (A) comprises: a structural unit derived from an alkyl (meth)acrylate having a linear or branched alkyl group with 3 to 30 carbon atoms; and a structural unit derived from a hydroxyl-containing monomer and / or a structural unit derived from a nitrogen-containing monomer.

[0036] [9] A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to any one of [1] to [8].

[0037]

[10] The pressure-sensitive adhesive sheet according to [9], which has a light transmittance of 10% or less at a wavelength of 380 nm.

[0038]

[11] The pressure-sensitive adhesive sheet according to [9] or

[10] , which has a light transmittance of 30% or less at a wavelength of 400 nm.

[0039]

[12] The pressure-sensitive adhesive sheet according to any one of [9] to

[11] , wherein the total light transmittance is 80% or more.

[0040]

[13] The pressure-sensitive adhesive sheet according to any one of [9] to

[10] , wherein the gel fraction (X0) is 20% or more.

[0041]

[14] The adhesive sheet according to

[13] , wherein the adhesive sheet is active energy ray-curable, and the adhesive sheet is exposed to an accumulated light intensity of 2000 to 4000 mJ / cm 2 The gel fraction (X1) when irradiated with active energy rays having a wavelength of 405 nm is 30% or more.

[0042]

[15] The pressure-sensitive adhesive sheet according to

[14] , wherein the difference (X1-X0) between the gel fraction (X1) and the gel fraction (X0) is 2% or more.

[0043]

[16] The adhesive sheet according to any one of [9] to

[15] , wherein the adhesive sheet is active energy ray-curable, and the adhesive sheet is exposed to an accumulated light intensity of 2000 to 4000 mJ / cm 2 The chromaticity (b*1) when irradiated with active energy rays having a wavelength of 405 nm is 2.5 or less, and the difference (b*1-b*0) from the chromaticity (b*0) before the active energy ray irradiation is 1.0 or less.

[0044]

[17] The pressure-sensitive adhesive sheet according to any one of [9] to

[16] , which is used for bonding optical components.

[0045]

[18] A pressure-sensitive adhesive sheet with a release film, comprising a structure in which the pressure-sensitive adhesive sheet according to any one of [9] to

[17] and a release film are laminated.

[0046]

[19] A laminate for an image display device, comprising a structure in which two optical members are laminated with the pressure-sensitive adhesive sheet according to any one of [1] to

[17] interposed therebetween.

[0047]

[20] An image display device comprising the laminate for an image display device according to

[19] .

[0048]

[21] A pressure-sensitive adhesive sheet for an organic EL display device, comprising the pressure-sensitive adhesive sheet according to any one of [9] to

[17] .

[0049]

[22] A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A) and a photoinitiator (B),

[0050] The photoinitiator (B) includes a compound represented by Formula 2 below.

[0051]

[0052] (In the above formula 2, A is O, S, NR4 Or a linear or branched alkylene group or cycloalkylene group having 1 to 6 carbon atoms.

[0053] R 1 is substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 3 ~C 20 Cycloalkyl or substituted or unsubstituted C 2 ~C 20 Heterocycloalkyl.

[0054] R 2 is a hydrogen atom, a substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 3 ~C 20 Cycloalkyl, substituted or unsubstituted C 2 ~C 20 Heterocycloalkyl, substituted or unsubstituted C 6 ~C 20 Aryl, substituted or unsubstituted C 1 ~C 20 Heteroaryl, SR 5 , OR 6 NR 7 R 8 、C(O)R 9 or C(O)OR 13 .

[0055] R 4 is selected from hydrogen atoms, C 1 ~C 18 Alkyl, C 2 ~C 18 Alkanoyl, C 6 ~C 10 Aryl and C 7 ~C 11 Aroyl radicals are groups in the group consisting of aroyl radicals.

[0056] R 5 and R 6 are each independently selected from a hydrogen atom, C 1 ~C 20 Alkyl, C 2 ~C 20 Alkanoyl, C 6 ~C 10 Aryl and C 7 ~C 11 Aroyl radicals are groups in the group consisting of aroyl radicals.

[0057] R 7 and R 8are each independently selected from a hydrogen atom, C 1 ~C 20 Alkyl, C 2 ~C 20 Alkanoyl, C 7 ~C 11 Aroyl, C 6 ~C 10 A group in the group consisting of aryl groups.

[0058] R 9 is selected from hydrogen atoms, C 1 ~C 20 Alkyl and C 6 ~C 20 A group in the group consisting of aryl groups.

[0059] R 13 With R 1 Same meaning.)

[0060]

[23] A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing a (meth)acrylic polymer (A), a photoinitiator (B) and a UV absorber (C),

[0061] The photoinitiator (B) includes a compound represented by Formula 2 below.

[0062]

[0063] (In the above formula 2, A is O, S, NR 4 Or a linear or branched alkylene group or cycloalkylene group having 1 to 6 carbon atoms.

[0064] R 1 is substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 3 ~C 20 Cycloalkyl or substituted or unsubstituted C 2 ~C 20 Heterocycloalkyl.

[0065] R 2 is a hydrogen atom, a substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 3 ~C 20 Cycloalkyl, substituted or unsubstituted C 2 ~C 20 Heterocycloalkyl, substituted or unsubstituted C 6 ~C 20 Aryl, substituted or unsubstituted C 1 ~C 20 Heteroaryl, SR5 , OR 6 NR 7 R 8 、C(O)R 9 or C(O)OR 13 .

[0066] R 4 is selected from hydrogen atoms, C 1 ~C 18 Alkyl, C 2 ~C 18 Alkanoyl, C 6 ~C 10 Aryl and C 7 ~C 11 Aroyl radicals are groups in the group consisting of aroyl radicals.

[0067] R 5 and R 6 are each independently selected from a hydrogen atom, C 1 ~C 20 Alkyl, C 2 ~C 20 Alkanoyl, C 6 ~C 10 Aryl and C 7 ~C 11 Aroyl radicals are groups in the group consisting of aroyl radicals.

[0068] R 7 and R 8 are each independently selected from a hydrogen atom, C 1 ~C 20 Alkyl, C 2 ~C 20 Alkanoyl, C 7 ~C 11 Aroyl, C 6 ~C 10 A group in the group consisting of aryl groups.

[0069] R 9 is selected from hydrogen atoms, C 1 ~C 20 Alkyl and C 6 ~C 20 A group in the group consisting of aryl groups.

[0070] R 13 With R 1 Same meaning.)

[0071] Effects of the Invention

[0072] The adhesive composition of the invention of the above-mentioned [1] can be cured by energy rays on the longer wavelength side, for example, energy rays with a wavelength longer than 380 nm, especially active energy rays of 405 nm, and has a small number of photodecomposition products. It can be suitable for adhesive sheets used in the bonding of optical components, especially adhesive sheets for organic EL display devices.

[0073] According to the invention of [2] above, there is provided an adhesive composition which has ultraviolet absorption, can be cured by active energy rays, and has a small amount of photodecomposition products.

[0074] The adhesive sheet using the invention of [2] has ultraviolet absorption and can be cured by active energy rays, and has a small amount of photodecomposition products. Therefore, it is suitable for adhesive sheets used for bonding optical members, especially adhesive sheets for organic EL display devices. DETAILED DESCRIPTION

[0075] Hereinafter, an example of an embodiment of the present invention will be described in detail, but the present invention is not limited to the embodiment described below.

[0076] In addition, in the present invention, the "film" conceptually includes a sheet, a film, and a tape.

[0077] In addition, when the term "panel" is used, such as an image display panel, a protective panel, etc., a plate body, a sheet, and a film are included.

[0078] In the present invention, when "x to y" (x and y are arbitrary numbers) is described, unless otherwise specified, it includes the meaning of "x or more and y or less" as well as "preferably greater than x" or "preferably less than y".

[0079] In addition, when it is recorded as "x or more" (x is an arbitrary number), unless otherwise specified, it includes the meaning of "preferably greater than x", and when it is recorded as "y or less" (y is an arbitrary number), unless otherwise specified, it also includes the meaning of "preferably less than y".

[0080] Furthermore, “x and / or y (x and y are arbitrary structures)” means at least one of x and y, that is, it means the following three types: only x, only y, and x and y.

[0081] In the present invention, “(meth)acrylic acid” includes acrylic acid and methacrylic acid, “(meth)acrylate” includes acrylate and methacrylate, and “(meth)acryloyl” includes acryloyl and methacryloyl.

[0082] The "(meth)acrylic polymer" means a polymer having a structural unit derived from a (meth)acrylic monomer. The (meth)acrylic polymer may also have a structural unit derived from a monomer other than the (meth)acrylic monomer (for example, styrene).

[0083] <<Adhesive composition>>

[0084] In the present invention, the PSA composition contains a (meth)acrylic polymer (A). By containing the (meth)acrylic polymer (A), the obtained PSA sheet can be soft and have good adhesive strength.

[0085] 1. First Implementation Method

[0086] The adhesive composition of the first embodiment of the present invention (hereinafter referred to as "the present adhesive composition 1") is characterized in that it contains a (meth)acrylic polymer (A) and a photoinitiator (B), wherein the photoinitiator (B) includes a photoinitiator (b1), and the photoinitiator (b1) has a glyoxylate structure and a molar absorption coefficient of light with a wavelength of 405 nm of 30 (L / mol·cm) or more. The present adhesive composition 1 does not contain a UV absorber.

[0087] The present adhesive composition can be suitably used for bonding optical members.

[0088] Hereinafter, each component contained in the present adhesive composition 1 will be described in detail.

[0089] <(Meth)acrylic acid polymer (A)>

[0090] Examples of the (meth)acrylic polymer (A) contained in the present pressure-sensitive adhesive composition 1 include, in addition to homopolymers of (meth)acrylic acid alkyl esters, copolymers obtained by polymerizing monomer components copolymerizable therewith.

[0091] Among them, the (meth)acrylic polymer preferably contains two or more copolymerization components, and at least one of the copolymerization components is an alkyl (meth)acrylate having an alkyl group with 3 to 30 carbon atoms.

[0092] More specifically, the (meth)acrylic polymer (A) may be a copolymer comprising a monomer component of a (meth)acrylic acid alkyl ester having an alkyl group with 3 to 30 carbon atoms and a monomer other than the (meth)acrylic acid alkyl ester copolymerizable therewith, wherein the monomer is any one or more selected from (a1) a carboxyl group-containing monomer, (a2) a hydroxyl group-containing monomer, (a3) ​​a nitrogen-containing monomer, (a4) an epoxy group-containing monomer, (a5) a vinyl monomer, (a6) a (meth)acrylic acid alkyl ester monomer having an alkyl group with 1 or 2 carbon atoms, (a7) an alicyclic monomer, and (a8) other copolymerizable monomers.

[0093] (1) Among the above-mentioned copolymerizable monomers (a1) to (a8), copolymerizable monomers (a1), (a2) or (a3) ​​are particularly preferred.

[0094] (2) In addition, it is particularly preferred that the copolymerizable monomer (a1) is not contained and any one of the copolymerizable monomers (a2) or (a3) ​​is contained. By containing any one of the copolymerizable monomers (a2) or (a3), it is possible to have both corrosion resistance when the adherend contains a corrosive component such as a metal, adhesion, and resistance to wet heat whitening. In addition, from the viewpoint of improving cohesion, it is particularly preferred to contain both the copolymerizable monomers (a2) and (a3).

[0095] (3) Furthermore, among the copolymerizable monomers (a3), those having a tertiary nitrogen atom are preferred from the viewpoint of having a sensitizing effect of the hydrogen abstraction reaction described below and, as a result, being able to efficiently form crosslinks.

[0096] (4) Among the above-mentioned alkyl (meth)acrylates, those containing a tertiary carbon atom in the alkyl group are preferred. By using such an alkyl (meth)acrylate, hydrogen abstraction reaction is easily caused during light irradiation, and as a result, crosslinking is easily and efficiently formed.

[0097] The alkyl (meth)acrylate is a linear or branched alkyl (meth)acrylate having an alkyl group with 3 to 30 carbon atoms, and is represented by the following formula (m1).

[0098] CH 2 =C(R 14 )-COO(R 15 )···Formula (m1)

[0099] (In formula m1, R 14 represents a hydrogen atom or a methyl group, R 15 represents a linear or branched alkyl group having 3 to 30 carbon atoms.

[0100] Examples of the alkyl (meth)acrylate represented by formula (m1) include n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, lauryl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, n-eicosyl (meth)acrylate, n-heneicosyl (meth)acrylate, behenyl (meth)acrylate, and the like. branched alkyl (meth)acrylates such as sec-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, isoeicosyl (meth)acrylate, butyl octyl (meth)acrylate, isomyristyl (meth)acrylate, isocetyl (meth)acrylate, hexyldecyl (meth)acrylate, isostearyl (meth)acrylate, octyldecyl (meth)acrylate, octyldodecyl (meth)acrylate, and isobehenyl (meth)acrylate. These can be used alone or in combination of two or more.

[0101] Among these, from the viewpoint of obtaining flexibility, linear alkyl (meth)acrylates are preferred. Furthermore, from the viewpoint of achieving a balance between adhesiveness and flexibility, alkyl (meth)acrylates having 3 to 20 carbon atoms in the alkyl group are preferred, alkyl (meth)acrylates having 5 to 18 carbon atoms are further preferred, alkyl (meth)acrylates having 6 to 16 carbon atoms are particularly preferred, and alkyl (meth)acrylates having 7 to 14 carbon atoms are particularly preferred, such as n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, and lauryl (meth)acrylate.

[0102] Among these, from the viewpoint that the hydrogen abstraction reaction described later is easily caused upon light irradiation and, as a result, a cross-linked structure can be efficiently formed, it is preferable to use a branched alkyl (meth)acrylate. Among them, a branched alkyl (meth)acrylate having 3 to 20 carbon atoms in the alkyl group is preferred, a branched alkyl (meth)acrylate having 5 to 18 carbon atoms is more preferred, a branched alkyl (meth)acrylate having 6 to 16 carbon atoms is particularly preferred, and a branched alkyl (meth)acrylate having 7 to 14 carbon atoms is particularly preferred. For example, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, and isodecyl (meth)acrylate are preferred.

[0103] The ratio of the structural unit derived from the above-mentioned alkyl (meth)acrylate to all structural units constituting the (meth)acrylic polymer (A) is preferably 5% by mass or more and 95% by mass or less, more preferably 10% by mass or more and 90% by mass or less, further preferably 15% by mass or more and 85% by mass or less, and particularly preferably 20% by mass or more and 80% by mass or less. If the ratio of the structural unit derived from the alkyl (meth)acrylate is above the aforementioned lower limit, there is a tendency for excellent flexibility, and there is a tendency for the adherend to have excellent concavoconvexity tracking when it has concavoconvexity. If it is below the aforementioned upper limit, there is a tendency for the effect of the copolymerizable monomer described later to be easily obtained and excellent adhesive force and cohesive force.

[0104] The lower limit and upper limit of the content of the structural unit derived from the alkyl (meth)acrylate may be arbitrarily combined.

[0105] Examples of the carboxyl-containing monomer (a1) include (meth) acrylic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyloxypropyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxypropyl phthalic acid, 2-(meth)acryloyloxyethyl maleic acid, 2-(meth)acryloyloxypropyl maleic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxypropyl succinic acid, crotonic acid, fumaric acid, maleic acid, and itaconic acid. These may be one or a combination of two or more.

[0106] Examples of the hydroxyl group-containing monomer (a2) include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate, caprolactone-modified hydroxy (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, diethylene glycol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, polytetramethylene glycol (meth)acrylate, and polyethylene oxide. (Meth)acrylates having an oxyalkylene structure such as polypropylene glycol (meth)acrylate, (meth)acrylates containing primary hydroxyl groups such as 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid; (meth)acrylates containing secondary hydroxyl groups such as 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-chloro-2-hydroxypropyl (meth)acrylate; (meth)acrylates containing tertiary hydroxyl groups such as 2,2-dimethyl 2-hydroxyethyl (meth)acrylate; and vinyl ethers such as 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, and 4-hydroxybutyl vinyl ether. These may be used alone or in combination of two or more.

[0107] The hydroxyl group-containing monomer (a2) can improve the adhesive strength of the adhesive sheet and suppress whitening due to moisture and heat. In addition, when the adhesive composition 1 contains a thermal crosslinking agent described later, it becomes a reaction point for crosslinking.

[0108] Among the aforementioned hydroxyl-containing monomers (a2), hydroxyl-containing monomers having a hydroxyalkyl group having 1 to 10 carbon atoms are preferred, more preferably a hydroxyalkyl group having 1 to 6 carbon atoms, and particularly preferably a hydroxyalkyl group having 2 to 4 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, 4-hydroxybutyl vinyl ether, etc., and particularly preferred are primary hydroxyl-containing (meth)acrylates, such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate.

[0109] From the viewpoint of imparting adhesive strength and resistance to whitening by moisture and heat, the content of the structural unit derived from the hydroxyl group-containing monomer (a2) in the (meth)acrylic polymer (A) is preferably 3 to 30% by mass, more preferably 5 to 25% by mass, and particularly preferably 7 to 20% by mass, based on the total structural units of the (meth)acrylic polymer (A).

[0110] As the above-mentioned nitrogen-containing monomer (a3), for example, in addition to amino-containing monomers, amide-containing monomers, and isocyanate-containing monomers, (methyl) acrylonitrile and the like can be cited. Utilizing nitrogen-containing monomers (a3), the cohesive force of the adhesive sheet can be improved and wet heat whitening can be suppressed. These can be one or a combination of two or more. In addition, nitrogen-containing monomers (a3) ​​have the effect of promoting the hydrogen abstraction reaction described later.

[0111] Examples of the amino group-containing monomers of the nitrogen-containing monomers include: (meth)acrylates containing primary amino groups such as aminomethyl (meth)acrylate and aminoethyl (meth)acrylate; (meth)acrylates containing secondary amino groups such as tert-butylaminoethyl (meth)acrylate and tert-butylaminopropyl (meth)acrylate; (meth)acrylates containing tertiary amino groups such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, diethylaminopropyl (meth)acrylate, and dimethylaminopropyl acrylamide; and monomers such as N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpiperazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinylacetamides, and N-vinylcaprolactam.

[0112] Examples of the amide group-containing monomer include (meth)acrylamide; N-alkyl(meth)acrylamide such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-n-butyl(meth)acrylamide, diacetone(meth)acrylamide, and N,N'-methylenebis(meth)acrylamide; N,N-dialkyl(meth)acrylamide such as N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-ethylmethacrylamide, and N,N-diallyl(meth)acrylamide; hydroxyalkyl(meth)acrylamide such as N-hydroxymethyl(meth)acrylamide and N-hydroxyethyl(meth)acrylamide; alkoxyalkyl(meth)acrylamide such as N-methoxymethyl(meth)acrylamide and N-(n-butoxymethyl)(meth)acrylamide; maleimide or its derivatives;

[0113] Examples of the isocyanate group-containing monomer include 2-(meth)acryloyloxyethyl isocyanate and alkylene oxide adducts thereof. The isocyanate group may be protected with a blocking agent such as methyl ethyl ketoxime, 3,5-dimethylpyrazole, 1,2,4-triazole, or diethyl malonate.

[0114] Among these, from the viewpoint of having a sensitizing effect of the hydrogen abstraction reaction described later and, as a result, being able to efficiently form a crosslinked structure, those having a tertiary nitrogen atom are preferred, and for example, (meth)acrylates containing a tertiary amino group, N,N-dialkyl (meth)acrylamide, N-vinyl pyrrolidone, acryloyl morpholine, and the like are particularly preferred.

[0115] From the viewpoint of imparting cohesive force and resistance to whitening by moisture and heat, the content of the structural unit derived from the nitrogen-containing monomer (a3) ​​in the (meth)acrylic polymer (A) is preferably 0.1 to 15% by mass, more preferably 0.5 to 13% by mass, particularly preferably 1 to 10% by mass, and particularly preferably 2 to 7% by mass, based on the total structural units of the (meth)acrylic polymer (A).

[0116] Examples of the epoxy group-containing monomer (a4) include glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate glycidyl ether. These may be used alone or in combination of two or more.

[0117] As the vinyl monomer (a5), compounds having a vinyl group in the molecule can be cited. Examples of such compounds include vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl laurate, and vinyl stearate, and aromatic vinyl monomers such as styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrenes. These can be one or a combination of two or more.

[0118] Examples of the (meth)acrylic acid alkyl ester monomer (a6) in which the alkyl group has 1 or 2 carbon atoms include methyl (meth)acrylate and ethyl (meth)acrylate, and these may be used alone or in combination of two or more.

[0119] From the viewpoint of imparting cohesive force to the pressure-sensitive adhesive sheet, the content of the structural unit derived from the copolymerizable monomer (a6) in the (meth)acrylic polymer (A) is preferably 0.1 to 15% by mass, more preferably 0.5 to 13% by mass, particularly preferably 1 to 10% by mass, and particularly preferably 2 to 7% by mass, based on the total structural units of the (meth)acrylic polymer (A).

[0120] Examples of the alicyclic monomer (a7) include cyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, and adamantyl (meth)acrylate. These may be used alone or in combination of two or more.

[0121] From the viewpoint of imparting cohesive force to the pressure-sensitive adhesive sheet, the content of the structural unit derived from the copolymerizable monomer (a7) in the (meth)acrylic polymer (A) is preferably 0.1 to 15% by mass, more preferably 0.5 to 13% by mass, particularly preferably 1 to 10% by mass, and particularly preferably 2 to 7% by mass, based on the total structural units of the (meth)acrylic polymer (A).

[0122] Examples of the other copolymerizable monomers (a8) include (meth)acrylates having an alkoxyalkylene glycol skeleton such as methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, butoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, butoxypolypropylene glycol (meth)acrylate, methoxypolytetramethylene glycol (meth)acrylate, butoxypolytetramethylene glycol (meth)acrylate, methoxypolyoxyethylenepolypropylene glycol (meth)acrylate, butoxypolyoxyethylenepolypropylene glycol (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenyldiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, phenoxypolyethylene glycol-polypropylene glycol-(meth)acrylate, nonylphenol ethylene oxide adduct (meth)acrylate, 4-Acryloyloxyethoxybenzophenone, 4-acryloyloxy-4'-methoxybenzophenone, 4-acryloyloxyethoxy-4'-methoxybenzophenone, 4-acryloyloxy-4'-bromobenzophenone, 4-acryloyloxyethoxy-4'-bromobenzophenone, 4-methacryloyloxybenzophenone, 4-methacryloyloxyethoxybenzophenone, 4-methacryloyloxy-4'-methoxybenzophenone, 4-methacryloyloxy-4'-bromobenzophenone, 4-methacryloyloxybenzophenone, 4-methacryloyloxyethoxybenzophenone, 4-methacryloyloxy-4'-methoxybenzophenone, 4-methacryloyloxy-4'-bromobenzophenone, 4-methacryloyloxyethoxy-4'-methoxybenzophenone, 4-methacryloyloxy-4'-bromobenzophenone, 4-methacryloyloxy-4'-bromobenzophenone, and mixtures thereof, (meth)acrylates having a benzophenone structure, such as tetrahydrofurfuryl (meth)acrylate, and macromonomers. These can be used individually or in combination of 2 or more types.

[0123] The content of the structural unit derived from the copolymerizable monomer (a8) in the (meth)acrylic polymer (A) is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and further preferably 5% by mass or more and 15% by mass or less, relative to all the structural units constituting the (meth)acrylic polymer (A). The lower limit and the upper limit of the above content may be arbitrarily combined.

[0124] The (meth)acrylic polymer (A) may introduce a photoactive site, such as a polymerizable carbon-carbon double bond group, into the side chain, thereby improving the crosslinking efficiency of the adhesive composition 1 and allowing the adhesive composition 1 to be crosslinked in a shorter time, thereby improving productivity.

[0125] As a method for introducing a polymerizable carbon-carbon double bond group into the side chain of the (meth)acrylic polymer (A), for example, the following method can be cited: a copolymer comprising the above-mentioned hydroxyl-containing monomer (a2) and an ethylenically unsaturated monomer containing a functional group is prepared, and then a compound having a functional group reactive with these functional groups and a polymerizable carbon-carbon double bond group is subjected to a condensation or addition reaction while maintaining the activity of the polymerizable carbon-carbon double bond group.

[0126] As the combination of these functional groups, there can be listed: epoxy (glycidyl) and carboxyl, amino and carboxyl, amino and isocyanate, epoxy (glycidyl) and amino, hydroxyl and epoxy, hydroxyl and isocyanate, etc. Among the combinations of these functional groups, from the viewpoint of easy control of the reaction, the combination of hydroxyl and isocyanate is preferred. Among them, the combination in which the copolymer has a hydroxyl group and the aforementioned compound has an isocyanate group is suitable.

[0127] Examples of the isocyanate compound having a polymerizable carbon-carbon double bond group include the above-mentioned 2-(meth)acryloyloxyethyl isocyanate and alkylene oxide adducts thereof.

[0128] From the viewpoint of improving adhesion and stress relaxation, the content of the compound having a functional group that can react with the aforementioned functional group and a polymerizable carbon-carbon double bond group is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, further preferably 1 part by mass or less, and particularly preferably 0.1 parts by mass or less, relative to 100 parts by mass of the (meth)acrylic polymer (A). It should be noted that the lower limit is usually 0 parts by mass.

[0129] From the viewpoint of obtaining the present pressure-sensitive adhesive composition 1 having high cohesive strength, the weight average molecular weight (Mw) of the (meth)acrylic polymer (A) is preferably 200,000 or more, more preferably 300,000 or more, and even more preferably 400,000 or more.

[0130] The upper limit of the weight average molecular weight (Mw) of the (meth)acrylic polymer (A) is preferably 1.5 million or less, more preferably 1.2 million or less, further preferably 1.1 million or less, and particularly preferably 1 million or less, from the viewpoint of handling properties and uniform stirring properties.

[0131] The lower limit and the upper limit of the weight average molecular weight of the (meth)acrylic polymer (A) may be arbitrarily combined.

[0132] The weight average molecular weight of the (meth)acrylic polymer (A) is a value in terms of standard polystyrene measured by gel permeation chromatography (GPC).

[0133] The method for producing the (meth)acrylic polymer (A) is not particularly limited, and a known method can be used. For example, a method can be used in which a (meth)acrylic acid alkyl ester having an alkyl group with 3 to 30 carbon atoms and a monomer mixture containing one or more selected from copolymerizable monomers (a1) to (a8) used as required are polymerized.

[0134] <Photoinitiator (B)>

[0135] The adhesive composition 1 contains, as the photoinitiator (B), a photoinitiator (b1) having a glyoxylate structure and a molar absorption coefficient of 30 (L / mol·cm) or more at a wavelength of 405 nm.

[0136] The photoinitiator is a compound that generates free radicals using active energy rays.

[0137] Photoinitiators are generally classified into two types according to their free radical generation mechanism. More specifically, they are roughly divided into cleavage-type photoinitiators that can generate free radicals by cleaving single bonds of the initiator itself and hydrogen abstraction-type photoinitiators that can generate free radicals by allowing the excited initiator to abstract hydrogen from a hydrogen donor in the system.

[0138] As a cleavage-type photoinitiator, the initiator itself becomes a free radical and performs an addition reaction on the polymerizable carbon-carbon double bond group in the system to perform a free radical addition reaction, so the (meth)acrylic polymer (A) has a polymerizable carbon-carbon double bond group, or a certain amount or more of the polymerizable carbon-carbon double bond group of the multifunctional (meth)acrylate is required to obtain sufficient active energy ray curing. When a certain amount or more of the multifunctional (meth)acrylate (D) is added, there are the following problems: due to the light irradiation during the production of the adhesive sheet, the reaction of the multifunctional (meth)acrylate (D) proceeds rapidly, so it is difficult to control the state to leave room for curing by active energy rays, or the adhesive force is reduced.

[0139] On the other hand, the hydrogen abstraction type photoinitiator abstracts hydrogen from hydrogen donors such as the (meth)acrylic polymer (A) in the system to generate free radicals in the (meth)acrylic polymer (A). Therefore, even if there is no polymerizable carbon-carbon double bond group in the system, the (meth)acrylic polymer (A) itself can be bonded by a free radical addition reaction, thereby obtaining sufficient active energy ray curing properties, and therefore it can be preferably used.

[0140] In addition, as photoinitiators having high photosensitivity to light in the long wavelength region, α-aminoacetophenone-based and acylphosphine oxide-based photoinitiators are mainly used, but these are cleavage-type photoinitiators and therefore generate outgassing such as benzaldehyde as a photodecomposition product, and improvement is strongly desired.

[0141] Furthermore, hydrogen abstraction type photoinitiators such as 9-thioxanthone and anthraquinone, which are conventionally known as photoinitiators having photosensitivity to light in the long wavelength region, do not generate photodecomposition products but have the problem of yellowing, and thus their use is limited.

[0142] Based on this situation, the present inventors conducted intensive studies and, as a result, obtained the following findings.

[0143] It is believed that glyoxylate-type hydrogen abstraction photoinitiators generally have low efficiency of hydrogen abstraction from hydrogen donors under light in the long wavelength region, and therefore do not undergo a curing reaction. However, it was found that by using a glyoxylate-type hydrogen abstraction photoinitiator having a molar absorption coefficient of 30 (L / mol·cm) or more at a wavelength of 405 nm, there were unexpectedly no disadvantages such as insufficient curing and yellowing, and curing was performed using energy rays on the long wavelength side, such as energy rays at a wavelength of 405 nm, thereby completing the present invention.

[0144] It should be noted that the glyoxylate-type photoinitiator is preferably a compound having an absorption wavelength in the range of 380 to 430 nm.

[0145] The molar absorption coefficient of the photoinitiator (b1) at 405 nm is 30 (L / mol·cm) or more, and thus the sensitivity to long-wavelength active energy rays is excellent. Therefore, by using the photoinitiator (b1), the present adhesive composition 1 that is cured by active energy rays of a longer wavelength, for example, active energy rays of 405 nm having a longer wavelength than 380 nm, can be obtained. From this viewpoint, the molar absorption coefficient is preferably 40 (L / mol·cm) or more, more preferably 50 (L / mol·cm) or more, further preferably 60 (L / mol·cm) or more, and particularly preferably 70 (L / mol·cm) or more.

[0146] It should be noted that from the viewpoint of internal (or deep) curing properties, the upper limit of the molar absorption coefficient is preferably 1.0×10 6 (L / mol·cm) or less, more preferably 5.0×10 5 (L / mol·cm) or less, more preferably 1.0×10 5 (L / mol·cm) or less, particularly preferably 5.0×10 4 (L / mol·cm) or less.

[0147] The lower limit and the upper limit of the molar absorption coefficient mentioned above can be arbitrarily combined.

[0148] The molar absorption coefficient of the photoinitiator (b1) at 405 nm is calculated according to the following formula by dissolving the photoinitiator (b1) at a predetermined concentration in chloroform or the like, measuring the absorbance at 405 nm using a UV-visible spectrophotometer.

[0149] A=εLc

[0150] (A represents absorbance, ε represents molar absorption coefficient (L / mol·cm), c represents molar concentration of photoinitiator (b1) (mol / L), and L represents optical path length (cm))

[0151] The photoinitiator (b1) has a glyoxylate structure represented by the following formula 1.

[0152]

[0153] In the above formula 1, R 1 is substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 3 ~C 20 Cycloalkyl or substituted or unsubstituted C 2 ~C 20 Heterocycloalkyl. * indicates a connecting bond.

[0154] It should be noted that “C 1 ~C 20 "Alkyl" refers to an alkyl group with 1 to 20 carbon atoms. 3 ~C 20 Cycloalkyl, C 2 ~C 20 The same applies to heterocycloalkyl and the like.

[0155] In the above formula 1, R 1 C 1 ~C 20 When alkyl, the aforementioned C 1 ~C 20 The alkyl group may be composed of one or more identical or different groups selected from O, S, N(R 3 ), C(O), C(O)O and OC(O) may be interrupted by one or more identical or different groups R 1a .

[0156] Here, the aforementioned R 1a Each independently selected from F, Cl, Br, I, CN, NO 2 , SR 5 , OR 6 NR 7 R8 、C(O)R 9 、C(O)OR 10 、C(O)NR 11 R 12 , C which may be interrupted by one or more C(O) groups 3 ~C 20 Cycloalkyl, C 6 ~C 10 A group consisting of an aryl group and a (meth)acryloyloxy group.

[0157] R 1a C 3 ~C 20 Cycloalkyl and C 6 ~C 10 The aryl group may have one or more than one identical or different radicals R 1aa .

[0158] R 1aa Each independently selected from C 1 ~C 12 Alkyl, C 2 ~C 12 Alkenyl, F, Cl, Br, I, NO 2 , SR 5 , OR 6 and NR 7 R 8 Composed of groups.

[0159] R 1aa C 1 ~C 12 The alkyl group may be selected from O, S, N(R 3) , C(O), C(O)O and OC(O) and may have a group selected from F, Cl, Br, I, NO 2 , SR 5 , OR 6 NR 7 R 8 、C(O)R 9 、C(O)OR 10 and C(O)NR 11 R 12 One or more identical or different groups in the group.

[0160] In the above formula 1, R 1 C 3 ~C 20 Cycloalkyl or C 2 ~C 20 When heterocycloalkyl, the aforementioned C 3 ~C 20Cycloalkyl or C 2 ~C 20 The heterocycloalkyl group may be interrupted by one or more C(O) groups and may have one or more identical or different groups R 1b .

[0161] Here, the aforementioned R 1b Each independently selected from C 1 ~C 12 Alkyl, C 2 ~C 12 Alkenyl, F, Cl, Br, I, CN, NO 2 , SR 5 , OR 6 and NR 7 R 8 Composed of groups.

[0162] R 1b C 1 ~C 12 The alkyl group may have a moiety selected from the group consisting of F, Cl, Br, I, NO 2 , SR 5 , OR 6 NR 7 R 8 、C(O)R 9 、C(O)OR 10 and C(O)NR 11 R 12 One or more identical or different groups in the group.

[0163] The aforementioned R 3 Selected from hydrogen atoms, C 1 ~C 18 Alkyl, C 2 ~C 18 Alkanoyl, C 6 ~C 10 Aryl and C 7 ~C 11 Aroyl group.

[0164] R 3 C 1 ~C 18 The alkyl group may be selected from O, S, N(C 1 ~C 12 alkyl), C(O), C(O)O and OC(O), and may have a radical selected from F, Cl, Br, I, C 3 ~C 10 Cycloalkyl, C 2 ~C 10 Heterocycloalkyl, C 6~C 10 One or more identical or different groups selected from the group consisting of aryl, OH and SH.

[0165] R 3 C 2 ~C 20 The alkanoyl group may be interrupted by one or more groups selected from the group consisting of O, S, CO, C(O)O and OC(O), and may have a group selected from the group consisting of F, Cl, Br, I, C 3 ~C 10 Cycloalkyl, C 2 ~C 10 Heterocycloalkyl and C 6 ~C 10 One or more identical or different groups in the group consisting of aryl groups.

[0166] R 3 C 6 ~C 10 The aryl group may have a moiety selected from the group consisting of F, Cl, Br, I, C 1 ~C 10 Alkyl, C 1 ~C 10 Alkoxy and C 2 ~C 11 One or more identical or different groups in the group consisting of acyloxy groups.

[0167] R 3 C 7 ~C 11 The aromatic acyl group may have a moiety selected from the group consisting of F, Cl, Br, I, C 1 ~C 10 Alkyl, C 1 ~C 10 Alkoxy and C 2 ~C 11 One or more identical or different groups in the group consisting of acyloxy groups.

[0168] The aforementioned R 5 and R 6 Each independently selected from a hydrogen atom, C 1 ~C 20 Alkyl, C 2 ~C 20 Alkanoyl, C 6 ~C 10 Aryl and C 7 ~C 11 Aroyl group.

[0169] R 5 and R 6 C 1 ~C20 The alkyl group may be selected from O, S, N(C 1 ~C 12 alkyl), C(O), C(O)O and OC(O), and may have a group selected from F, Cl, Br, I, C 3 ~C 10 Cycloalkyl, C 2 ~C 10 Heterocycloalkyl, C 6 ~C 10 One or more identical or different groups selected from the group consisting of aryl, OH and SH.

[0170] R 5 and R 6 C 2 ~C 20 The alkanoyl group may be interrupted by one or more groups selected from the group consisting of O, S, C(O), C(O)O and OC(O), and may have a group selected from the group consisting of F, Cl, Br, I, C 3 ~C 10 Cycloalkyl, C 2 ~C 10 Heterocycloalkyl and C 6 ~C 10 One or more identical or different groups in the group consisting of aryl groups.

[0171] R 5 and R 6 C 6 ~C 10 The aryl group may have a moiety selected from the group consisting of F, Cl, Br, I, C 1 ~C 6 Alkyl, C 1 ~C 10 Alkoxy and C 2 ~C 11 One or more identical or different groups in the group consisting of acyloxy groups.

[0172] R 5 and R 6 The C7-C11 aromatic acyl group may have a member selected from the group consisting of F, Cl, Br, I, C 1 ~C 10 Alkyl, C 1 ~C 10 Alkoxy and C 2 ~C 11 One or more identical or different groups in the group consisting of acyloxy groups.

[0173] The aforementioned R 7 and R 8Each independently selected from a hydrogen atom, C 1 ~C 20 Alkyl, C 2 ~C 20 Alkanoyl, C 7 ~C 11 Aroyl, C 6 ~C 10 A group consisting of aromatic groups.

[0174] R 7 and R 8 C 1 ~C 20 The alkyl group may be selected from O, S, N(C 1 ~C 12 alkyl), C(O), C(O)O and OC(O), and may have a group selected from F, Cl, Br, I, NO 2 , C 3 ~C 10 One or more identical or different groups selected from the group consisting of cycloalkyl, heterocycloalkyl, phenyl, OH, SH and CN.

[0175] R 7 and R 8 C 2 ~C 20 The alkanoyl group may be interrupted by one or more groups selected from the group consisting of O and S, and may have a group selected from the group consisting of F, Cl, Br, I, OH and C 1 ~C 6 One or more of the alkoxy groups may be the same or different.

[0176] R 7 and R 8 C 7 ~C 11 The aromatic acyl group may have a moiety selected from the group consisting of F, Cl, Br, I, C 1 ~C 6 Alkyl, -OH and C 1 ~C 6 One or more of the alkoxy groups may be the same or different.

[0177] R 7 and R 8 C 6 ~C 10 The aryl group may have a moiety selected from the group consisting of F, Cl, Br, I, C 1 ~C 6 Alkyl, -OH and C 1 ~C 6One or more of the alkoxy groups may be the same or different.

[0178] R 7 and R 8 Together with the nitrogen atom to which they are bonded, they can form a saturated 5-, 6- or 7-membered nitrogen heterocyclic ring, wherein the aforementioned ring may have a member selected from O, S, N (C 1 ~C 12 alkyl), C(O) and C(O)O as ring members, and the aforementioned ring may also have one or more C 1 ~C 4 alkyl.

[0179] The aforementioned R 9 Selected from hydrogen atoms, C 1 ~C 20 Alkyl and C 6 ~C 20 A group consisting of aromatic groups.

[0180] R 9 C 1 ~C 20 The alkyl group may be interrupted by one or more groups selected from the group consisting of O, S and C(O), and may have one or more identical or different R 9a .

[0181] R 9a Each independently selected from F, Cl, Br, I, C 3 ~C 10 The group consisting of cycloalkyl, heterocycloalkyl, phenyl, OH and SH.

[0182] R 9 C 6 ~C 20 The aryl group may have a moiety selected from F, Cl, Br, I, SR 5 , OR 6 NR 7 R 8 , C 1 ~C 12 Alkyl and C 2 ~C 12 One or more identical or different groups in the group consisting of acyloxy groups.

[0183] R 10 With R 6 Same meaning.

[0184] R 11 and R 12 With R 7 , R 8 Same meaning.

[0185] By having a glyoxylate structure, the photoinitiator (b1) functions as a hydrogen abstraction type photoinitiator.

[0186] From the viewpoint of not generating photodecomposition products like cleavage-type photoinitiators, hydrogen abstraction-type photoinitiators are preferred. In addition, hydrogen abstraction-type photoinitiators also cause hydrogen abstraction reaction from the (meth)acrylic polymer (A), and the (meth)acrylic polymer (A) is introduced into the cross-linked structure, so they are also preferred from the viewpoint of easily forming a cross-linked structure with many cross-linking points.

[0187] It should be noted that hydrogen abstraction photoinitiators are roughly divided into intermolecular hydrogen abstraction photoinitiators that abstract hydrogen from other molecules and intramolecular hydrogen abstraction photoinitiators that also cause hydrogen abstraction reactions within the same molecule. By having the glyoxylate structure, the photoinitiator (b1) functions as an intramolecular hydrogen abstraction photoinitiator.

[0188] From the viewpoint that not only the hydrogen donor in the system can serve as a starting point for the generation of free radicals but also the hydrogen donor itself can serve as a starting point for the generation of free radicals, an intramolecular hydrogen abstraction type photoinitiator is preferred.

[0189] From the perspective of solubility, R 1 It is preferably a linear or branched alkyl group or a cycloalkyl group, and more preferably a linear or branched alkyl group.

[0190] From the perspective of photocurability, R 1 The number of carbon atoms in the alkyl group is preferably 1 to 20, more preferably 1 to 12, further preferably 1 to 8, and particularly preferably 1 or 2.

[0191] From the perspective of photocurability, R 1 The cycloalkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms.

[0192] The photoinitiator (b1) is preferably a compound having two or more radical generating groups in the molecule (wherein at least one radical generating group is a glyoxylate structure). Here, the "radical generating group" refers to a group that generates a radical that initiates a polymerization reaction when excited by active energy rays.

[0193] The “radical generating group” is particularly preferably a group having a structure that is excited by irradiation with active energy rays and undergoes a hydrogen abstraction reaction to generate a radical.

[0194] When the photoinitiator (b1) has two or more radical-generating groups, the present adhesive composition 1 can be efficiently crosslinked.

[0195] Examples of the radical generating group other than the glyoxylate structure include a benzophenone structure, a bibenzoyl structure, a thioxanthone structure, a 3-ketocoumarin structure, an anthraquinone structure, and a camphorquinone structure.

[0196] From the viewpoint of improving the sensitivity to long-wavelength active energy rays and the molar absorption coefficient at a wavelength of 405 nm, the photoinitiator (b1) is preferably a compound having a biphenyl structure bonded to a connecting bond of a glyoxylate structure as shown in Formula 1, and particularly preferably a compound having a thiobiphenyl structure bonded to a connecting bond of a glyoxylate structure as shown in Formula 1.

[0197] Examples of the photoinitiator (b1) include compounds represented by the following formula 2.

[0198]

[0199] In the above formula 2, A is O, S, NR 4 or a linear or branched alkylene group or a cycloalkylene group having 1 to 6 carbon atoms.

[0200] Here, R 4 With R 3 Same meaning. 1 Same as the above formula 1.

[0201] R 2 is a hydrogen atom, a substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 3 ~C 20 Cycloalkyl, substituted or unsubstituted C 2 ~C 20 Heterocycloalkyl, substituted or unsubstituted C 6 ~C 20 Aryl, substituted or unsubstituted C 1 ~C 20 Heteroaryl, SR 5 , OR 6 NR 7 R 8 、C(O)R 9 C(O)OR 13 Here R 13 With R 1 Same meaning.

[0202] In the above formula 2, R 2 C 1 ~C 20 When alkyl, the aforementioned C 1 ~C 20 The alkyl group may be one or more identical or different groups selected from O, S, N (R 3), C(O), C(O)O and OC(O) groups are interrupted, and may have one or more identical or different groups R 2a .

[0203] Here, R 2a With R 1a Same meaning.

[0204] In the above formula 2, R 2 C 3 ~C 20 Cycloalkyl or C 2 ~C 20 When heterocycloalkyl, the aforementioned C 3 ~C 20 Cycloalkyl or C 2 ~C 20 The heterocycloalkyl group may be interrupted by one or more C(O) groups, and may have one or more identical or different groups R 2b Here R 2b With R 1b Same meaning.

[0205] In the above formula 2, R 2 C 6 ~C 20 Aryl or C 1 ~C 20 In the case of heteroaryl, the aforementioned C 6 ~C 20 Aryl or C 1 ~C 20 The heteroaryl group may have one or more identical or different groups R 2c .

[0206] The aforementioned R 2c Each independently selected from C 1 ~C 12 Alkyl, C 2 ~C 12 Alkenyl, F, Cl, Br, I, CN, NO 2 , SR 5 , OR 6 NR 7 R 8 、C(O)R 9 、C(O)OR 10 、C(O)NR 11 R 12 , C 6 ~C 10 Aryl, C 1 ~C 20 Heteroaryl, C 3 ~C 10 Cycloalkyl and C 2~C 10 A group consisting of heterocycloalkyl.

[0207] R 2c C 1 ~C 12 The alkyl group may have a moiety selected from F, Cl, Br, I, NO 2 , SR 5 , OR 6 NR 7 R 8 、C(O)R 9 、C(O)OR 10 and C(O)NR 11 R 12 1 or more than 1 of the same or different groups.

[0208] R 2c C 1 ~C 12 Alkyl, C 3 ~C 10 Cycloalkyl and C 2 ~C 10 The heterocycloalkyl group may be interrupted by one or more than one C(O) group.

[0209] R 2c C 6 ~C 10 Aryl, C 1 ~C 20 Heteroaryl, C 3 ~C 10 Cycloalkyl and C 2 ~C 10 The heterocycloalkyl group may have one or more identical or different groups R 1ca Here, R 1ca With the aforementioned R 1aa Same meaning.

[0210] From the viewpoint of photoreactivity, among the compounds represented by Formula 2, diphenyl sulfide derivatives in which A is a sulfur atom are preferred.

[0211] In addition, from the viewpoint of photoreactivity, among these, R 2 Preferably, it is a substituted or unsubstituted aromatic group having 6 to 20 carbon atoms or (O)OR 13 . R 13 With R 1 Same meaning.

[0212] As the photoinitiator (b1), at least one selected from the group consisting of compounds represented by the following formulae 3 to 5 is more preferred.

[0213]

[0214] Here, n is an integer of 0-5.

[0215]

[0216] Here, o is an integer of 0-3, and p is an integer of 0-4.

[0217] Among these, the photoinitiator (b1) preferably contains R in the above formulae 3 to 5. 1 and R 13 The compound is a linear or branched alkyl group having 1 to 8 carbon atoms, and n, o, and p are 0, and particularly preferably includes any one or both of the compound represented by the following formula 3-1 and the compound represented by the following formula 4-1.

[0218]

[0219] The photoinitiator (b1) can be used alone or in combination of two or more.

[0220] The content of the photoinitiator (b1) in the present adhesive composition 1 is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and further preferably 1 part by mass or more relative to 100 parts by mass of the (meth) acrylic polymer (A). In addition, the upper limit is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, further preferably 5 parts by mass or less, and particularly preferably 3 parts by mass or less. If the content of the photoinitiator (b1) is above the aforementioned lower limit, there is a tendency to prevent poor curing, and if it is below the aforementioned upper limit, there is a tendency to suppress the exudation of the photoinitiator (b1) and easily suppress the problems of embrittlement and coloring. The lower limit and upper limit of the content of the photoinitiator (b1) can be arbitrarily combined.

[0221] The adhesive composition 1 may further contain a photoinitiator (b2) other than the photoinitiator (b1) as the photoinitiator (B) as long as the effects of the present invention are not impaired. The photoinitiator (b2) may be any of a hydrogen abstraction type photoinitiator and a cleavage type photoinitiator, and they may be used alone or as a mixture of both. In addition, one or more of each may be used.

[0222] In addition, the terms in the above-mentioned photoinitiator (b1) are defined as follows.

[0223] The term "alkyl" in the photoinitiator (b1) generally refers to a saturated linear or branched hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 10 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, and n-eicosyl.

[0224] The alkyl group may be composed of one or more identical or different groups selected from O, S, N (R 3 ), C(O), C(O)O and OC(O) groups are interrupted. 3 ), C(O), C(O)O and OC(O), they are usually separated from each other by at least one methylene group. 3 As defined above. Examples of alkyl groups interrupted by one or more O atoms are: -CH 2 -O-CH 3 、-CH 2 CH 2 -O-CH 2 CH 3 、-[CH 2 CH 2 O] y -CH 3 (y is 1 to 9), -(CH 2 CH 2 O) y CH 2 CH 3 (y is 1 to 9), -CH 2 -CH(CH 3 )-O-CH 2 -CH 2 CH 3 、-CH 2 -CH 2 CH(CH 3 )-O-CH 2 -CH 2 CH 3 、-CH 2 -CH 2 CH(CH 3 )-O-CH 2 CH 3 、-CH 2 -CH 2 CH(CH 3 )-O-CH 3 and CH 2CH(CH 3 )-O-CH 2 CH 3 .

[0225] The term "cycloalkyl group" in the photoinitiator (b1) generally refers to a monocyclic or polycyclic aliphatic group having 3 to 20 carbon atoms, preferably 3 to 16 carbon atoms, and more preferably 3 to 12 carbon atoms.

[0226] Examples of the monocyclic aliphatic group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group, and a cyclopentyl group and a cyclohexyl group are particularly preferred.

[0227] Examples of the polycyclic ring include perhydroanthracenyl, perhydronaphthyl, perhydrofluorenyl, perhydrochrysenyl, perhydropicenyl, adamantyl, bicyclo[1.1.1]pentyl, bicyclo[2.2.1]heptyl, bicyclo[4.2.2]decyl, bicyclo[2.2.2]octyl, bicyclo[3.3.0]octyl, bicyclo[3.3.2]decyl, bicyclo[4.4.0]decyl, bicyclo[4.3.2]undecyl, bicyclo[4.3.3]dodecyl, bicyclo[3.3.3]undecyl, bicyclo[4.3.1]decyl, bicyclo[4.2.1]nonyl, bicyclo[3.3.1]nonyl and bicyclo[3.2.1]octyl.

[0228] The cycloalkyl group may be interrupted by one or more than one C(O) group. An example of a cycloalkyl group interrupted by one C(O) group is 3-oxobicyclo[2.2.1]heptyl.

[0229] The term "heterocycloalkyl" in the photoinitiator (b1) generally refers to a 3- to 8-membered, particularly 5-, 6-, 7- or 8-membered, monocyclic heterocyclic non-aromatic group and a bicyclic heterocyclic non-aromatic group. The aforementioned monocyclic and bicyclic non-aromatic groups may be saturated or unsaturated. In addition, the aforementioned monocyclic and bicyclic heterocyclic non-aromatic groups generally contain 1, 2, 3 or 4 heteroatoms selected from N, O and S, particularly 1 or 2 heteroatoms as ring members, in which case the S atom as a ring member may be S, SO or SO 2 The heterocycloalkyl group may be interrupted by one or more than one C(O) group, usually by one or two groups.

[0230] Examples of the saturated or unsaturated 3- to 8-membered non-aromatic heterocyclic group include an oxiranyl group, an oxetanyl group, a thietanyl group, a thietanyl-S-oxide (S-oxothietanyl group), a thietanyl-S-dioxide (S-dioxothietanyl group), a pyrrolidinyl group, a pyrazolyl group, an imidazolinyl group, a pyrrolinyl group, a pyrazolyl group, an imidazolinyl group, a tetrahydrofuranyl group, a dihydrofuranyl group, a 1,3-dioxolyl group, a dioxolyl group, a thiolanyl group, an S-oxothiolyl group, an S-dioxothiolyl group, a dihydrothiolanyl group, a dihydrothiolanyl group, a S-oxydihydrothiolanyl group, a S-dioxodihydrothiolanyl group, an oxadiazolyl group, a thiolanyl group, a thiolanyl group, a thiolanyl group, a thiolanyl group, a thiolanyl group, a thiolanyl group, a thiolanyl group, a thiolanyl group, a thiolanyl group, a thiolanyl group oxazolidinyl, isoxazolidinyl, oxazolinyl, isoxazolinyl, thiazolinyl, isothiazolinyl, thiazolidinyl, isothiazolidinyl, oxathiolanyl, piperidinyl, piperazinyl, pyranyl, dihydropyranyl, tetrahydropyranyl, 1,3- and 1,4-dioxane, thiopyranyl, S-oxothipyranyl, S-dioxothipyranyl, dihydrothiopyranyl, S-oxodihydrothiopyranyl, S-dioxodihydrothiopyranyl, tetrahydrothiopyranyl, S-oxotetrahydrothiopyranyl, S-dioxotetrahydrothiopyranyl, morpholinyl, thiomorpholinyl, S-oxothiomorpholinyl, S-dioxothiomorpholinyl, thiazinyl.

[0231] Examples of the heterocyclic ring also containing one or two carbonyl groups as ring members include pyrrolidin-2-onyl, pyrrolidin-2,5-dione, imidazolidin-2-onyl, oxazolidin-2-onyl and thiazolidin-2-onyl.

[0232] The term "aryl" in the photoinitiator (b1) refers to a monovalent monocyclic aromatic group and a polycyclic aromatic group having a ring carbon atom. As a monocyclic aromatic group, for example, a phenyl group can be cited. As a polycyclic aromatic group, for example, a bicyclic, tricyclic or tetracyclic aromatic group can be cited, such as a naphthyl, a phenanthrenyl, an anthracenyl or a pyrene group. Preferred examples of the aryl group are phenyl and naphthyl. The substituted phenyl group is substituted with 1, 2, 3, 4 or 5 substituents. The naphthyl group is usually substituted with 1, 2, 3, 4, 5, 6 or 7 substituents, preferably with 1, 2, 3 or 4 substituents. Substituted phenyl groups are, for example, pentafluorophenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-ethoxyphenyl, 3-ethoxyphenyl, 4-ethoxyphenyl, 3-nitrophenyl, 4-nitrophenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl, 3-vinylphenyl, 4-vinylphenyl, 4-trifluoromethylphenyl, and 3,5-diethoxycarbonylphenyl.

[0233] The term "heteroaryl" in the photoinitiator (b1) generally refers to an unsaturated monocyclic heterocyclic group and a polycyclic heterocyclic group that are aromatic. The heteroaryl group generally contains 1, 2, 3 or 4 heteroatoms selected from N, O and S as ring members in addition to 1 or more carbon atoms as ring members. Examples of the monocyclic heteroaromatic group include 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 1-pyrazolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isoxazolyl, 4-isoxazolyl or 5-isoxazolyl, 3-isothiazolyl, 4-isothiazolyl or 5-isothiazolyl, 1-imidazolyl, 2-imidazolyl, 4-imidazolyl, 2- or 5-[1,3,4]oxadiazolyl, 4- or 5-(1,2,3-oxadiazolyl), 3- or 4- or 5-(1,2,3-thiadiazol)yl, 3- or 5-(1,2,4-thiadiazol)yl, 1H-, 2H- or 3H-1,2,3-triazol-4-yl, 1,3,4-triazol-2-yl, 2H-triazol-3-yl, 1H-, 2- or 4H-1,2,4-triazolyl, 1H- or 2H-tetrazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 3-pyridazinyl, 4-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl and 2-pyrazinyl. Examples of the polycyclic heterocyclic group include benzofuranyl, benzothiophenyl, indolyl, indazolyl, benzimidazolyl, benzoxathiazolyl, benzoxadiazolyl, benzothiadiazolyl, benzoxazinyl, quinolyl, isoquinolyl, purinyl, 1,8-naphthyridinyl, pteridinyl, pyrido[3,2-d]pyrimidinyl, pyridoimidazolyl, carbazolyl, and acridinyl.

[0234] The term "alkanoyl" in the photoinitiator (b1) is alkyl-C(O), which generally refers to a saturated straight-chain or branched alkyl group as defined above having 3 to 20 carbon atoms, and a group formed by bonding a carbon atom of a carbonyl group at any position in the alkyl group, such as acetyl, propionyl, 2-methyl-propionyl, butyryl, valeryl, and hexanoyl.

[0235] The term "aroyl group" in the photoinitiator (b1) is aryl-C(O), which refers to a group formed by bonding to any position of the aryl group defined above through the carbon atom of the carbonyl group, for example, benzoyl and naphthoyl.

[0236] The term "heteroaroyl group" in the photoinitiator (b1) is heteroaryl-C(O), and refers to a group formed by bonding to any position of the heteroaryl group defined above through the carbon atom of the carbonyl group.

[0237] The term "alkylene" in the photoinitiator (b1) refers to an alkyl group having carbon atoms as defined above in each case, and is a group formed by replacing one hydrogen atom at any position of the alkyl group with another bonding site to form a divalent group. 1 ~C 6 The alkylene group includes a divalent branched or unbranched saturated aliphatic chain having 1 to 6 carbon atoms, for example, -CH 2 -、-CH 2 CH 2 -、-CH(CH 3 )-、-CH 2 CH 2 CH 2 -、-CH(CH 3 )CH 2 -、-C(CH 3 ) 2 -、-CH 2 CH 2 CH 2 CH 2 -、-CH 2 CH(CH 3 )CH 2 -、-CH(CH 3 )CH(CH 3 )-、-CH 2 CH 2 CH 2 CH 2 CH 2 -、-CH 2 CH 2 CH 2 CH(CH 3 )-、-CH 2 C(CH 3 ) 2 CH 2 -、-CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 -.

[0238] The term "cycloalkylene" in the photoinitiator (b1) refers to the cycloalkyl group defined above, and is a group in which a hydrogen atom at any position of the cycloalkyl group is replaced by another bonding site to form a divalent group. In the case of a polycyclic cycloalkylene group, these bonding points are located at any position in the same ring or in different rings. Examples of monocyclic rings include cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene or cycloheptylene, particularly cyclohexylene. Examples of the polycyclic ring include perhydroanthracenylene, perhydronaphthylene, perhydrofluorenylene, perhydrochrysene, perhydronaphthylene, adamantylene, bicyclo[1.1.1]pentylene, bicyclo[2.2.1]heptylene, bicyclo[4.2.2]decylene, bicyclo[2.2.2]octylene, bicyclo[3.3.2]decylene, bicyclo[4.3.2]undecylene, bicyclo[4.3.3]dodecylene, bicyclo[3.3.3]undecylene, bicyclo[4.3.1]decylene, bicyclo[4.2.1]nonylene, bicyclo[3.3.1]nonylene, and bicyclo[3.2.1]octylene.

[0239] As for the hydrogen abstraction type photoinitiator as the above-mentioned photoinitiator (b2), for example, benzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzophenone, 4-phenylbenzophenone, 3,3'-dimethyl-4-methoxybenzophenone, 2-benzoylbenzoic acid methyl ester, 4-[(4-methylphenyl)thio]benzophenone, 4-acryloxybenzophenone, 4-acryloxyethoxybenzophenone, 4-acryloxy-4'-methoxybenzophenone, 4-acryloxyethoxy-4'-methoxybenzophenone, 4-acryloxy-4'-bromobenzophenone, 4-acryloxyethoxy -4'-bromobenzophenone, 4-methacryloyloxybenzophenone, 4-methacryloyloxyethoxybenzophenone, 4-methacryloyloxy-4'-methoxybenzophenone, 4-methacryloyloxyethoxy-4'-methoxybenzophenone, 4-methacryloyloxy-4'-bromobenzophenone, 4-methacryloyloxyethoxy-4'-bromobenzophenone and the like intermolecular hydrogen abstraction type photoinitiators; methyl benzoylformate, 2-(2-oxo-2-phenyl-acetoxy-ethoxy)ethyl oxyphenylacetate, 2-(2-hydroxy-ethoxy)ethyl oxyphenylacetate and the like.

[0240] Among these, 4-acryloxybenzophenone, 4-acryloxyethoxybenzophenone, 4-acryloxy-4'-methoxybenzophenone, 4-acryloxyethoxy-4'-methoxybenzophenone, etc., which have a radical polymerizable functional group having a carbon-carbon double bond in the molecule, are preferred from the viewpoint that they are introduced into the polymerized structure after the photoreaction, thereby suppressing the bleeding of the photoinitiator and improving the cohesive force of the adhesive sheet.

[0241] In addition, an intramolecular hydrogen abstraction type photoinitiator is preferred from the viewpoint that not only the hydrogen donor in the system but also the hydrogen donor itself can become the starting point of radical generation.

[0242] Furthermore, as the photoinitiator (b2), a cleavage-type photoinitiator may be used to the extent that the photodecomposition product does not affect the quality. From the viewpoint of having high photosensitivity, a cleavage-type photoinitiator is preferred.

[0243] Examples of the cleavage-type photopolymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)benzyl]phenyl}-2-methyl-1-propanone, oligo(2-hydroxy-2-methyl-1-(4-(1-methylvinyl)phenyl)propanone), 2-benzyl-2-dimethylamino -1-(4-morpholinophenyl)-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholino)phenyl]-1-butanone, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl)ethoxyphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)2,4,4-trimethylpentylphosphine oxide, and derivatives thereof.

[0244] The content of the photoinitiator (b2) in the adhesive composition 1 is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, further preferably 3 parts by mass or less, and particularly preferably 2 parts by mass or less, based on 100 parts by mass of the (meth)acrylic polymer (A). The lower limit is usually 0 parts by mass.

[0245] <Multifunctional (meth)acrylate (D)>

[0246] From the viewpoint of promoting the crosslinking reaction, the adhesive composition 1 preferably contains a multifunctional (meth)acrylate (D). Thus, for example, the adhesive composition 1 can also quickly form a crosslinked structure under the same light irradiation amount. In addition, if a crosslinked structure is formed in an adhesive sheet using the adhesive composition 1, it is possible to prevent the paste from overflowing during storage or when rolled into a roll, and good adhesion and cohesion can be obtained.

[0247] However, when the acrylic polymer (A) can undergo hydrogen abstraction reaction due to the action of the photoinitiator (B) or the like and a sufficient crosslinking structure is formed within the acrylic polymer (A) and / or between acrylic polymers (A), it is not essential to contain the polyfunctional (meth)acrylate (D).

[0248] Examples of the polyfunctional (meth)acrylate (D) include (meth)acrylic monomers and (meth)acrylic oligomers having two or more functional groups, etc. These can be used alone or in combination of two or more.

[0249] Examples of the (meth)acrylic monomer having two or more functional groups include pentanediol di(meth)acrylate, hexanediol di(meth)acrylate, heptanediol di(meth)acrylate, octanediol di(meth)acrylate, nonanediol di(meth)acrylate, decanediol di(meth)acrylate, undecanediol di(meth)acrylate, dodecanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, glycerol di(meth)acrylate, and neopentyl glycol di(meth)acrylate. meth)acrylate, glyceryl glycidyl ether di(meth)acrylate, tricyclodecane dimethacrylate, tricyclodecane dimethanol di(meth)acrylate, bisphenol A polyethoxy di(meth)acrylate, bisphenol A polypropoxy di(meth)acrylate, bisphenol F polyethoxy di(meth)acrylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane trioxyethyl (meth)acrylate, ε-caprolactone modified tris(2-hydroxyethyl) isocyanurate tris(meth)acrylate (Meth)acrylate, pentaerythritol tri(meth)acrylate, propoxylated pentaerythritol tri(meth)acrylate, ethoxylated pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, tri(acryloyloxyethyl) hydroxypivalate di(meth)acrylate, di(meth)acrylate of ε-caprolactone adduct of hydroxypivalate, trimethylolpropane tri(meth)acrylate, trimethylolpropane polyethoxy tri(meth)acrylate, di(trimethylolpropane) tetra(meth)acrylate, and the like.

[0250] Examples of the polyfunctional (meth)acrylic oligomer include polyester (meth)acrylate oligomers, epoxy (meth)acrylate oligomers, urethane (meth)acrylate oligomers, and polyether (meth)acrylate oligomers.

[0251] Among these, from the viewpoint of imparting appropriate flexibility to a cured product, a (meth)acrylate monomer and oligomer having a diol structure are preferred.

[0252] From the viewpoint of providing shape stability of the adhesive sheet and durability when the laminate is made into an image display device, the content of the multifunctional (meth)acrylate (D) in the adhesive composition 1 is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and further preferably 1 part by mass or more relative to 100 parts by mass of the (meth)acrylic polymer (A). In addition, from the viewpoint of maintaining the flexibility of the adhesive sheet, the upper limit is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, further preferably 12 parts by mass or less, particularly preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less.

[0253] The lower limit and upper limit of the content of the polyfunctional (meth)acrylate (D) may be arbitrarily combined.

[0254] Furthermore, from the viewpoint of further increasing the crosslinking density and improving long-term reliability, a thermal crosslinking agent may be used in combination with the polyfunctional (meth)acrylate (D).

[0255] Examples of the thermal crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, aldehyde crosslinking agents, amine crosslinking agents, and metal chelate crosslinking agents. Among these, isocyanate crosslinking agents are preferably used because of their excellent reactivity with the (meth)acrylic polymer (A).

[0256] <Other ingredients>

[0257] The adhesive composition 1 may contain various additives such as silane coupling agents, plasticizers, tackifying resins, antioxidants, light stabilizers, metal deactivators, anti-aging agents, moisture absorbers, rust inhibitors, inorganic particles, etc. as "other ingredients" as needed, as long as the effects of the present invention are not impaired.

[0258] Furthermore, a reaction catalyst such as a tertiary amine compound, a quaternary ammonium compound, or a tin laurate compound may be appropriately contained as necessary.

[0259] These can be used alone or in combination of two or more.

[0260] [Silane coupling agent]

[0261] Silane coupling agents are organic silicon compounds containing one or more reactive functional groups and alkoxy groups bonded to silicon atoms in their structures. Examples of the reactive functional groups include epoxy groups, (meth)acryloyl groups, mercapto groups, hydroxyl groups, carboxyl groups, amino groups, amide groups, and isocyanate groups. Among these, epoxy groups and mercapto groups are preferred from the perspective of durability balance.

[0262] As the alkoxy group bonded to the silicon atom, from the viewpoint of durability and storage stability, an alkoxy group having 1 to 8 carbon atoms is preferred, and a methoxy group and an ethoxy group are particularly preferred. It should be noted that the silane coupling agent may have an organic substituent other than the reactive functional group and the alkoxy group bonded to the silicon atom, such as an alkyl group, a phenyl group, etc.

[0263] Examples of the silane coupling agent used in the present invention include: 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc., which are monomeric epoxy-containing silane compounds; hydrolysis and polycondensation of a part of the above silane compounds; or the above silane compounds and methyltriethoxysilane, ethyltriethoxysilane. , methyltrimethoxysilane, ethyltrimethoxysilane and other alkyl-containing silane compounds are co-condensed to form an oligomer type epoxy-containing silane coupling agent as a silane compound; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane, 3-mercaptopropylmethyldimethoxysilane and other silane compounds as monomeric mercapto-containing silane coupling agents; hydrolysis and polycondensation of a part of the aforementioned silane compounds or the aforementioned silane compounds and methyltriethoxysilane, ethyltriethoxysilane Silane coupling agents containing a mercapto group as oligomers of silane compounds, which are obtained by co-condensing silane compounds containing an alkyl group such as trimethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane; silane coupling agents containing (meth)acryloyl groups, such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane; N-2-(aminoethyl)-3-amino Amino group-containing silane coupling agents such as propylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane; vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane, etc.

[0264] These may be used alone or in combination of two or more.

[0265] Among these, epoxy group-containing silane coupling agents and mercapto group-containing silane coupling agents are preferably used from the viewpoint of excellent durability, and epoxy group-containing silane coupling agents are particularly preferred.

[0266] The content of the silane coupling agent in the adhesive composition 1 is preferably 0.005 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and particularly preferably 0.05 to 1 part by mass, relative to 100 parts by mass of the (meth)acrylic polymer (A). If the content is above the lower limit, durability tends to be improved, while if it is below the upper limit, durability tends to be improved.

[0267] [Plasticizer]

[0268] The present PSA composition 1 may contain a plasticizer in order to impart flexibility to the PSA sheet.

[0269] Examples of the plasticizer include, but are not limited to, those selected from the group consisting of polyisobutylene, polyisoprene, polybutadiene, amorphous polyolefins and copolymers thereof, silicone, polyacrylate, oligomer polyurethane, ethylene propylene copolymers, and any combination or mixture thereof.

[0270] Among these, the plasticizer is preferably polyisobutylene. Examples of the polyisobutylene plasticizer that can be used in the present specification include products commercially available under the trade name OPPANOL from BASF, particularly products selected from the OPPANOL B series.

[0271] From the viewpoint of environmental protection, the smaller the volatile organic compound value (VOC) of the plasticizer used, the better. When measured by thermogravimetric analysis, it is preferably less than 1000 ppm, more preferably less than 800 ppm, further preferably less than 600 ppm, and most preferably less than 400 ppm.

[0272] The content of the plasticizer in the present pressure-sensitive adhesive composition 1 is not particularly limited, but is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, based on 100 parts by mass of the (meth)acrylic polymer (A).

[0273] [Thickener]

[0274] The present adhesive composition 1 may contain a tackifier in order to improve the adhesive strength of the adhesive sheet.

[0275] Examples of the tackifier include terpene resins such as polyterpene (e.g., α-pinene resin, β-pinene resin, and limonene resin) and aromatic modified polyterpene resins (e.g., phenol-modified polyterpene resin), 2,3-dihydrobenzofuran-indene resin (coumaran-inden resin), petroleum resins such as C5 hydrocarbon resins, C9 hydrocarbon resins, C5 / C9 hydrocarbon resins, and dicyclopentadiene resin, and rosins such as modified rosin, hydrogenated rosin, polymerized rosin, and rosin esters.

[0276] The content of the tackifier in the pressure-sensitive adhesive composition 1 is not particularly limited, but is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, based on 100 parts by mass of the (meth)acrylic polymer (A).

[0277] [Rust inhibitor]

[0278] The adhesive composition 1 may contain a rust inhibitor in order to prevent corrosion when the adherend includes a corrosive portion such as a metal wiring.

[0279] Examples of the rust inhibitor include triazoles and benzotriazoles.

[0280] The content of the rust inhibitor in the adhesive composition 1 is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass or less, based on 100 parts by mass of the (meth)acrylic polymer (A).

[0281] The method for preparing the adhesive composition 1 is not particularly limited. For example, the adhesive composition 1 is prepared by mixing the (meth)acrylic polymer (A) and the photoinitiator (b1), and other components such as the photoinitiator (b2), the multifunctional (meth)acrylate (D), and the silane coupling agent as required in predetermined amounts.

[0282] The pressure-sensitive adhesive composition obtained in this manner can be preferably used in a pressure-sensitive adhesive sheet, particularly a pressure-sensitive adhesive sheet for bonding optical members.

[0283] The adhesive composition 1 may be in a slurry state. The slurry component at this time may include an acrylic polymer and a monomer component. In one example, such a slurry component may be formed by so-called partial polymerization, or may be prepared by adding a monomer to a polymer formed by complete polymerization or a partially polymerized polymer of the monomers constituting the (meth)acrylic polymer (A). That is, if a prescribed monomer composition is partially polymerized, a part of the monomers is polymerized to form an oligomer or a polymer and a part of the monomers remain, thereby forming a slurry component. In addition, in another example, a slurry may be prepared by adding a monomer component to a partially polymerized or completely polymerized polymer.

[0284] Therefore, the structural unit derived from the monomer constituting the (meth)acrylic polymer (A) in the present specification may refer to a monomer present in the form of an oligomer or a polymer among the components of the acrylic polymer, or a monomer contained in the syrup component before polymerization.

[0285] 2. Second Implementation Method

[0286] The adhesive composition of the second embodiment of the present invention (hereinafter referred to as "the present adhesive composition 2") is characterized in that it contains a (meth) acrylic polymer (A), a photoinitiator (B) and an ultraviolet absorber (C), wherein the photoinitiator (B) includes a photoinitiator (b1), and the photoinitiator (b1) has a glyoxylate structure and a molar absorption coefficient of light of a wavelength of 405 nm of 30 (L / mol·cm) or more. The present adhesive composition 2 is the same as the present adhesive composition 1 of the first embodiment except that it contains an ultraviolet absorber (C).

[0287] The present adhesive composition 2 can be suitably used for bonding optical members.

[0288] <Ultraviolet absorber (C)>

[0289] The present adhesive composition 2 contains an ultraviolet absorber (C). Image display components are generally susceptible to ultraviolet degradation, but by using an adhesive sheet formed from the present adhesive composition 2 containing the ultraviolet absorber (C), it is easy to prevent the image display components from being degraded by light.

[0290] In addition, since the present adhesive composition 2 contains an ultraviolet absorber (C), when it is photocured, it is preferably cured by active energy rays having a wavelength other than the absorption wavelength of the ultraviolet absorber (C).

[0291] Examples of the ultraviolet absorber (C) include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers, salicylic acid ultraviolet absorbers, and cyanoacrylate ultraviolet absorbers, etc. These ultraviolet absorbers may be used alone or in combination of two or more.

[0292] Examples of the benzophenone-based ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfonyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfonyloxybenzophenone trihydrate, 2,2'-dihydroxy-4-methoxy Benzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfonyloxybenzophenone sodium, bis(5-benzoyl-4-hydroxy-2-methoxyphenyl)methane, 2-hydroxy-4-n-dodecyloxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, etc.

[0293] Examples of the benzotriazole ultraviolet absorber include 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2-hydroxy-3,5-diisopropylphenyl)phenylbenzotriazole, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-chlorobenzotriazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol], 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, and 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole. 2-(2-hydroxy-5-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-pentylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-4-octyloxyphenyl)benzotriazole, 2,2'-methylenebis(4-isopropylphenyl-6-benzotriazolephenyl), 2,2'-p-phenylenebis(1,3-benzoxazine-4-one), 2-[2-hydroxy-3-(3,4,5,6-tetrahydrophthalimidomethyl)-5-methylphenyl]benzotriazole, etc.

[0294] Examples of the triazine-based ultraviolet absorber include 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-ethoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-propoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-butoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyl-1,3,5-triazine, and 2-(2-hydroxy-4-octyloxyphenyl)- 4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-benzyloxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3-5-triazine, 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-[1-octyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1 ,3,5-triazine, 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2,4-dimethylphenyl)-6 -[2-hydroxy-4-(3-octyloxy-2-hydroxypropoxy)-5-α-isopropylphenyl]-s-triazine, 2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-nonyloxy-2-hydroxypropoxy)-5-α-isopropylphenyl]-s-triazine, 2,4-bis(2,4-dimethylphenyl)-6-[2-hydroxy-4-(3-decyloxy-2-hydroxypropoxy)-5-α-isopropylphenyl]-s-triazine, 2-(2-hydroxy-4-acryloyloxyethoxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, etc.

[0295] Examples of the salicylic acid-based ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate.

[0296] Examples of the cyanoacrylate-based ultraviolet absorber include 2-ethylhexyl-2-cyano-3,3′-diphenylacrylate and ethyl-2-cyano-3,3′-diphenylacrylate.

[0297] Among these, from the viewpoint of effectively suppressing the light reaching the components of the image display device, benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers and triazine-based ultraviolet absorbers are preferred. In addition, from the viewpoint of excellent yellowing resistance, benzophenone-based ultraviolet absorbers and triazine-based ultraviolet absorbers are more preferred. In addition, from the viewpoint of being able to block light up to the long wavelength region, ultraviolet absorbers having absorption in a wavelength region longer than a wavelength of 400 nm are preferred.

[0298] As a commercial item of an ultraviolet absorber, "Tinosorb S" manufactured by BASF JAPAN CO., LTD., "KEMISORB111" manufactured by CHEMIPRO KASEIKAISHA, LTD., "CONFOGUARDUV002" manufactured by FUJIFILM CORPORATION, etc. are mentioned, for example.

[0299] From the viewpoint of improving light resistance reliability, the lower limit of the content of the ultraviolet absorber (C) in the present adhesive composition 2 is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, further preferably 0.5 parts by mass or more, particularly preferably 1 part by mass or more, and particularly preferably 1.5 parts by mass or more, relative to 100 parts by mass of the aforementioned (meth)acrylic polymer (A). On the other hand, from the viewpoint of suppressing bleeding and suppressing coloring, the upper limit of the content of the ultraviolet absorber (C) is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, further preferably 10 parts by mass or less, particularly preferably 8 parts by mass or less, particularly preferably 5 parts by mass or less, and most preferably 3 parts by mass or less.

[0300] The preparation method of the present adhesive composition 2 is not particularly limited. For example, the present adhesive composition is prepared by mixing the (meth)acrylic polymer (A), the photoinitiator (b1), the ultraviolet absorber (C), and other components such as the photoinitiator (b2), the multifunctional (meth)acrylate (D), and the silane coupling agent as required in predetermined amounts.

[0301] The pressure-sensitive adhesive composition obtained in this manner can be preferably used for a pressure-sensitive adhesive sheet, particularly a pressure-sensitive adhesive sheet for bonding optical members.

[0302] The present adhesive composition 2 may be in a slurry form similarly to the present adhesive composition 1.

[0303] <<Adhesive Sheet>>

[0304] The adhesive sheet of the present invention (hereinafter also referred to as "the present adhesive sheet") is an adhesive sheet having an adhesive layer formed from the present adhesive composition 1 or the present adhesive composition 2. The present adhesive sheet is particularly useful as an adhesive sheet for an organic EL display device.

[0305] The present adhesive sheet may be a single-layer sheet including only an adhesive layer formed from the present adhesive composition 1 or the present adhesive composition 2 (hereinafter also referred to as “the present adhesive layer”), or a multilayer sheet including a plurality of laminated present adhesive layers.

[0306] <Physical properties of this adhesive sheet>

[0307] The present pressure-sensitive adhesive sheet may have the following physical properties.

[0308] [Gel fraction (X0)]

[0309] The gel fraction (X0) of the present adhesive sheet is preferably 20% or more. If the gel fraction of the present adhesive sheet is above the lower limit, it is easy to fully maintain the shape. From this viewpoint, the gel fraction (X0) is more preferably 25% or more, further preferably 30% or more, and particularly preferably 35% or more.

[0310] Furthermore, from the viewpoint of obtaining flexibility, the gel fraction (X0) of the present pressure-sensitive adhesive sheet is preferably 90% or less, more preferably 80% or less, further preferably 70% or less, further preferably 60% or less, further preferably 55% or less, and particularly preferably 50% or less.

[0311] The lower limit and upper limit of the gel fraction (X0) may be arbitrarily combined.

[0312] The gel fraction (X0) is a measure of the degree of crosslinking (degree of curing), and can be measured under the measurement conditions described in the examples described below.

[0313] The adhesive sheet is preferably active energy ray-curable. Here, “active energy ray-curable adhesive sheet” means an adhesive sheet having a property of being curable by active energy rays, in other words, an adhesive sheet having room for curing by active energy rays.

[0314] The adhesive sheet may be: the adhesive composition 1 or the adhesive composition 2 is cured to a state where there is room for curing with active energy rays (hereinafter, also referred to as "primary curing"), or: the adhesive composition 1 or the adhesive composition 2 is cross-linked with a thermal cross-linking agent (primary curing) and can be cured with active energy rays. The adhesive sheet in the primary cured state can be cured by irradiating active energy rays before or after being attached to the adherend (hereinafter, also referred to as "secondary curing").

[0315] In addition, when the present pressure-sensitive adhesive sheet has active energy ray-curing properties, the "gel fraction (X0)" means the gel fraction of the pressure-sensitive adhesive sheet in a state in which the pressure-sensitive adhesive sheet has been cured once.

[0316] The primary curing of the pressure-sensitive adhesive sheet may be performed by heat or active energy rays. From the viewpoint of easily controlling the gel fraction (X0) within a predetermined range, the pressure-sensitive adhesive sheet is preferably cured by active energy ray irradiation.

[0317] The active energy ray used in the primary curing is preferably an active energy ray having a wavelength longer than 380 nm, and more preferably an active energy ray having a wavelength longer than 400 nm.

[0318] When the adhesive sheet is cured primarily by active energy rays, for example, it is preferred that the cumulative irradiation amount be 10 to 4000 mJ / cm2 at 405 nm. 2 The active energy ray irradiation is preferably 50 mJ / cm 2 Above and 3500mJ / cm 2 Below, more preferably 100 mJ / cm 2 Above and 3000mJ / cm 2 Below, particularly preferably 200 mJ / cm 2 Above and 2500mJ / cm 2 Below, more preferably 300 mJ / cm 2 Above and 2000mJ / cm 2 If the irradiation amount is within the above range, there is a tendency that a margin for curing can be left and the degree of curing can be adjusted, which is preferred.

[0319] In addition, when the active energy rays are irradiated from both sides, the above-mentioned active energy ray irradiation amount is the sum of the cumulative energy on one side and the cumulative energy on the other side.

[0320] [Gel fraction (X1)]

[0321] When the adhesive sheet has active energy ray curability, the adhesive sheet is exposed to an accumulated light intensity of 2000 to 4000 mJ / cm 2 The gel fraction (X1) after irradiation with active energy rays having a wavelength of 405 nm (after secondary curing) is preferably 30% or more, more preferably 40% or more, further preferably 50% or more, and particularly preferably 60% or more.

[0322] When the gel fraction (X1) after the secondary curing is 30% or more, the laminate for an image display device using the pressure-sensitive adhesive sheet will have excellent durability.

[0323] In addition, the difference (X1-X0) between the gel fraction (X1) after the aforementioned secondary curing and the gel fraction (X0) before active energy ray irradiation (before the secondary curing), i.e., the primary curing state, is preferably 2% or more, more preferably 10% or more, further preferably 15% or more, and particularly preferably 20% or more. By making the difference (X1-X0) greater than the above lower limit, it is possible to take into account at a higher level both the adhesion of the adhesive sheet to the component when it is attached to the component of the image display device and the durability of the laminate for the image display device after attachment.

[0324] The gel fraction (X1) can be measured by the method described in the following Examples.

[0325] [Adhesion]

[0326] The adhesive strength of the present adhesive sheet to soda-lime glass at a peeling angle of 180° and a peeling speed of 60 mm / min is preferably 3.0 N / cm or more, more preferably 4.0 N / cm or more, and even more preferably 5.0 N / cm or more.

[0327] [Adhesion after curing]

[0328] When the adhesive sheet has active energy ray curing properties, the adhesive sheet is bonded to soda lime glass and the accumulated light intensity is 2000 to 4000 mJ / cm 2 When irradiated with active energy rays having a wavelength of 405 nm in a manner, the adhesive strength (adhesive strength after curing) to soda-lime glass is preferably higher than the aforementioned adhesive strength at a peeling angle of 180° and a peeling speed of 60 mm / min.

[0329] Specifically, the adhesive strength after curing is preferably 5.0 N / cm or more, more preferably 6.0 N / cm or more, and even more preferably 7.0 N / cm or more. When the adhesive strength after curing is 5.0% or more, the laminate for an image display device using the adhesive sheet has excellent durability.

[0330] [Chroma]

[0331] The cumulative light intensity of this adhesive sheet is 2000 to 4000 mJ / cm 2 The chromaticity (b*1) when irradiated with active energy rays having a wavelength of 405 nm is preferably 2.5 or less, more preferably 2.0 or less, further preferably 1.5 or less, and particularly preferably 1.0 or less.

[0332] The difference (b*1-b*0) between the chromaticity (b*1) after the active energy ray irradiation and the chromaticity (b*0) before the active energy ray irradiation of the present pressure-sensitive adhesive sheet is preferably 1.0 or less, more preferably 0.5 or less, further preferably 0.1 or less, and particularly preferably 0 or less.

[0333] When (b*1) and (b*1-b*0) satisfy the above ranges, it is possible to obtain a PSA sheet that is suppressed from yellowing due to irradiation with active energy rays.

[0334] The chromaticity (b*1) and chromaticity (b*0) can be measured by the method described in the following Examples.

[0335] Photoinitiators that are highly sensitive to light in the long wavelength region generally have the problem of being easily colored, but acylphosphine oxide-based photoinitiators have a photobleaching effect and are therefore widely used in applications where coloration is a concern. However, this is believed to be an effect that occurs when cleavage-type photoinitiators decompose after photoreaction, and hydrogen abstraction-type photoinitiators that do not undergo photodecomposition have no photobleaching effect.

[0336] However, it was found that by using the photoinitiator (b1), surprisingly, although it is a hydrogen abstraction type photoinitiator, not only does it not turn yellow after light irradiation, but also obtains a photobleaching effect. The adhesive sheet not only does not produce photodecomposition products, but also has ultraviolet absorption, and has excellent active energy ray curing properties and coloring resistance, so it can be used for image display devices.

[0337] [Light transmittance]

[0338] The light transmittance of the adhesive sheet at a wavelength of 380 nm is preferably 10% or less. By having such optical properties, it is easy to protect the components of the image display device from degradation due to ultraviolet rays. From this point of view, the light transmittance is more preferably 7% or less, further preferably 5% or less, and particularly preferably 3% or less.

[0339] The light transmittance of the adhesive sheet at a wavelength of 400 nm is preferably 30% or less. By having such optical properties, even components of an image display device that are easily degraded by light can be fully protected from the impact of incident light. From this viewpoint, the light transmittance is more preferably 20% or less, further preferably 10% or less, and particularly preferably 5% or less.

[0340] The light transmittance can be measured by the method described in the following Examples.

[0341] [Total light transmittance, haze]

[0342] The total light transmittance of the pressure-sensitive adhesive sheet is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more.

[0343] The total light transmittance can be measured by the method described in the following examples.

[0344] The haze of the present pressure-sensitive adhesive sheet is preferably 1.0% or less, more preferably 0.8% or less, and even more preferably 0.5% or less. When the haze of the present pressure-sensitive adhesive sheet is 1.0% or less, it can be used as a pressure-sensitive adhesive sheet for image display devices requiring transparency.

[0345] The haze can be measured using a haze meter.

[0346] In order to set the haze of the present pressure-sensitive adhesive sheet to the above range, the present pressure-sensitive adhesive sheet preferably does not contain particles such as organic particles.

[0347] <Thickness>

[0348] The thickness of the present adhesive sheet is not particularly limited. If it is 10 μm or more, the handling property is good. If it is 1000 μm or less, it is helpful to thin the present adhesive sheet. From this viewpoint, the thickness of the present adhesive sheet is preferably 10 μm or more, more preferably 15 μm or more, further preferably 20 μm or more, and particularly preferably 25 μm or more. On the other hand, with respect to the upper limit, it is preferably 1000 μm or less, more preferably 500 μm or less, further preferably 400 μm or less, particularly preferably 300 μm or less, and particularly preferably 250 μm or less.

[0349] <Method for producing the present adhesive sheet>

[0350] Next, the method for producing the present pressure-sensitive adhesive sheet will be described.

[0351] However, the following description is an example of a method for producing the present pressure-sensitive adhesive sheet, and the present pressure-sensitive adhesive sheet is not limited to one produced by this production method.

[0352] The adhesive sheet can be prepared, for example, by preparing the adhesive composition 1, molding the adhesive composition 1 into a sheet, subjecting it to crosslinking, i.e., polymerization reaction to cure it, and performing appropriate processing as required. Alternatively, the adhesive composition 1 can be prepared, applied to a component constituting an image display device, and the adhesive composition 1 can be cured to form the adhesive sheet.

[0353] The same applies to the case of using the present adhesive composition 2.

[0354] When preparing the present adhesive composition 1 or the present adhesive composition 2, the aforementioned raw materials can be mixed using a propeller stirrer or a kneading machine (eg, a single-screw extruder, a twin-screw extruder, a planetary mixer, a twin-shaft mixer, a pressure kneader, etc.).

[0355] It should be noted that when mixing various raw materials, various additives such as silane coupling agents and antioxidants can be mixed (blended) with the resin in advance and then supplied to the stirrer or kneader, or all materials can be melt-mixed in advance and then supplied, or a masterbatch can be prepared in which only the additives are concentrated in the resin and then supplied.

[0356] As a method for forming the present adhesive composition 1 or the present adhesive composition 2 into a sheet, a known method can be used, such as a wet lamination method, a dry lamination method, an extrusion casting method using a T-die, an extrusion lamination method, a calendaring method, a blow molding method, an injection molding method, a liquid injection curing method, etc. Among them, when manufacturing a sheet, a wet lamination method, an extrusion casting method, and an extrusion lamination method are preferred.

[0357] The curing of the adhesive composition 1 or the adhesive composition 2 can be performed by irradiating active energy rays, and the adhesive sheet can be produced by irradiating an article, for example, a sheet, of the adhesive composition 1 with active energy rays. In addition to irradiation with active energy rays, heating can also be performed to further achieve curing.

[0358] The irradiation energy, irradiation time, irradiation method, etc. of the active energy ray are not particularly limited as long as the photopolymerization initiator can be activated to crosslink the present adhesive composition 1 or the present adhesive composition 2 .

[0359] As the active energy rays in the above-mentioned active energy ray irradiation, for example, there can be listed: far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, visible rays and other rays, X-rays, α rays, β rays, γ rays, electron beams, proton beams, neutron rays and other ionizing radiation. Among them, from the viewpoint of suppressing damage to components of the image display device and easily controlling the reaction, ultraviolet rays or visible rays are suitable. In addition, from the viewpoints of curing speed, ease of obtaining irradiation devices, price, etc., curing using ultraviolet irradiation or visible light irradiation is also advantageous. Among them, from the viewpoint of preventing curing inhibition caused by ultraviolet absorbers, it is preferred to use visible rays, such as 405nm active energy rays for curing.

[0360] Examples of light sources for active energy ray irradiation include high pressure mercury lamps, ultra-high pressure mercury lamps, low pressure mercury lamps, carbon arc lamps, metal halide lamps, xenon lamps, chemical lamps, electrodeless discharge lamps, and LEDs that emit light in the wavelength region of 150 to 450 nm.

[0361] The active energy ray irradiation dose (cumulative light dose) is preferably 10 to 6000 mJ / cm from the viewpoint of curing. 2 , more preferably 50 mJ / cm 2 ~5500mJ / cm 2, more preferably 100 mJ / cm 2 ~5000mJ / cm 2 , particularly preferably 200 mJ / cm 2 ~4000mJ / cm 2 , especially preferably 300mJ / cm 2 ~3000mJ / cm 2 .

[0362] As another embodiment of the method for producing the present adhesive sheet, the adhesive composition may be dissolved in a suitable solvent and applied using various coating methods. When the adhesive composition is in a slurry state, it may be applied without using a solvent.

[0363] When the coating method is used, the present adhesive sheet can be obtained by heat curing in addition to the curing by irradiation with active energy rays. During coating, the thickness of the present adhesive sheet can be adjusted by the coating thickness and the solid content concentration of the coating liquid.

[0364] For example, after the adhesive composition is dissolved in a solvent, it can be applied to a release film and dried, and solidified by active energy ray irradiation to form this adhesive sheet. And then, the release film can be stacked as required. In this case, it can be applied to a release film and dried, solidified by active energy ray irradiation, and a release film is stacked thereon. In addition, it can also be applied to a release film and dried, after the release film is stacked, it is solidified by active energy ray irradiation to form this adhesive sheet.

[0365] The solvent is not particularly limited as long as it can dissolve the present adhesive composition 1 or the present adhesive composition 2, and examples thereof include ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, and ethyl acetoacetate, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, aromatic solvents such as toluene and xylene, and alcohol solvents such as methanol, ethanol, and propanol. These can be used alone or in combination of two or more. Among them, ethyl acetate, acetone, methyl ethyl ketone, and toluene are preferred from the viewpoints of solubility, dryness, and price, and ethyl acetate is particularly suitable.

[0366] The amount of the solvent used is preferably 600 parts by mass or less, more preferably 500 parts by mass or less, further preferably 400 parts by mass or less, and particularly preferably 300 parts by mass or less, based on 100 parts by mass of the (meth)acrylic polymer (A), from the perspective of drying properties. On the other hand, it is preferably 1 part by mass or more, more preferably 50 parts by mass or more, further preferably 100 parts by mass or more, and particularly preferably 150 parts by mass or more.

[0367] As the coating method, for example, a conventional method such as roll coating, die coating, gravure coating, comma coating, screen printing, or bar coating can be used.

[0368] The solvent content in the dried adhesive composition is preferably 1% by mass or less, more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0% by mass.

[0369] The drying temperature is usually 40 to 150° C., more preferably 45 to 140° C., further preferably 50 to 130° C., particularly preferably 55 to 120° C. Within the above temperature range, thermal deformation of the release film can be suppressed and the solvent can be removed efficiently and relatively stably.

[0370] The drying time is usually 1 to 30 minutes, more preferably 3 to 25 minutes, and even more preferably 5 to 20 minutes. When the drying time is within the above range, the solvent can be removed efficiently and sufficiently.

[0371] Examples of drying methods include drying with a dryer, drying with a hot roller, and drying by blowing hot air to the film. Among them, a dryer is preferably used from the viewpoint of being able to dry evenly and easily. These can be used alone or in combination of two or more.

[0372] <<Adhesive sheet with release film>>

[0373] The present pressure-sensitive adhesive sheet may be provided as a pressure-sensitive adhesive sheet with a release film (pressure-sensitive adhesive sheet laminate) by laminating a release film on one or both surfaces of the pressure-sensitive adhesive sheet.

[0374] When release films are provided on both sides of the adhesive sheet, it is preferred to form a laminate structure in which a light release film with relatively low release force and a heavy release film with relatively high release force are laminated. When using an adhesive sheet with release films provided on both sides, first, peel off the release film (light release film) on one side to expose one side of the adhesive sheet, and then bond it to a component of the image display device (set as the first component), peel off the release film (heavy release film) on the other side, and bond other components of the image display device (set as the second component) to the other side of the exposed adhesive sheet.

[0375] As the release film, a known release film can be used appropriately.

[0376] As the material of the release film, for example, a film obtained by coating a release agent such as silicone resin on a film such as polyester film, polyolefin film, polycarbonate film, polystyrene film, acrylic film, cellulose triacetate film, fluororesin film, etc., and subjected to release treatment, release paper, etc. can be appropriately selected and used. From the viewpoint of excellent transparency, mechanical strength, heat resistance, flexibility, etc., polyester film, and further polyethylene terephthalate (PET) film, especially biaxially stretched PET film, is preferred. A release film having a release layer provided on such a substrate can be used, wherein the release layer is formed by curing a curable silicone-based release agent having a silicone resin as a main component.

[0377] The thickness of the release film is not particularly limited, but is preferably 10 to 250 μm, more preferably 25 to 200 μm, and even more preferably 35 to 190 μm, from the viewpoint of processability and handling properties.

[0378] <Preferred uses of the present pressure-sensitive adhesive sheet>

[0379] The adhesive sheet is suitable for laminating optical components. Specifically, it is suitable for laminating components constituting a display, especially components used in manufacturing a display, and is used as an adhesive sheet for laminating an image display panel with a protective panel, a touch panel or other image display device component disposed on its front surface side (visible side), or components constituting the aforementioned image display device component.

[0380] It should be noted that, as components of the image display device, the same components as those described below can be used.

[0381] <<Laminate for image display device>>

[0382] An image display device laminate (hereinafter sometimes referred to as "the present image display device laminate") of an example of an embodiment of the present invention is an image display device laminate having a structure in which two image display device constituent members are laminated with the present adhesive sheet sandwiched therebetween. The present image display device laminate is preferably an image display device laminate having a structure in which two image display device constituent members are laminated with the present adhesive sheet sandwiched therebetween.

[0383] Among the components of the laminate for the image display device, the pressure-sensitive adhesive sheet is as described above, and components other than the pressure-sensitive adhesive sheet are described below.

[0384] <Image display device constituent members>

[0385] As image display device constituent members constituting the laminate for the present image display device, for example, flat-panel image display device constituent members and flexible image display device constituent members can be listed. As such image display device constituent members, for example, flexible displays such as liquid crystal displays, organic electroluminescent (EL) displays, cover lenses (cover films), polarizing plates, polarizers, phase difference films, barrier films, viewing angle compensation films, brightening films, contrast enhancement films, diffusion films, semi-transmitting reflective films, electrode films, transparent conductive films, metal mesh films, touch sensor films, etc. can be listed. Any one of these or two of the two can be used in combination. For example, a combination of a flexible display and other image display device constituent members, a combination of a cover lens and other image display device constituent members can be listed.

[0386] It should be noted that the flexible image display device constituent member refers to a bendable member, a member used in an image display device having a curved surface shape, and a member that can be bent repeatedly. Particularly preferably, it is a member that can be fixed in a curved shape with a curvature radius of 25 mm or more, and in particular, it is a member that can withstand a bending action with a curvature radius of less than 25 mm, and more preferably, it is a member that can withstand a bending action with a curvature radius of less than 3 mm.

[0387] In the above-mentioned structure, as a member which comprises the structural member of an image display device, a resin sheet, glass, etc. are mentioned.

[0388] As the material of the resin sheet, for example, polyester resin, cycloolefin resin, cellulose triacetate resin, polymethyl methacrylate resin, polyurethane, epoxy resin, polyimide resin and aramid resin can be listed. These can be one resin or two or more resins. Among them, a resin sheet containing at least one resin selected from the group consisting of polyester resin, cycloolefin resin, cellulose triacetate resin, polymethyl methacrylate resin, epoxy resin, polyimide resin, aramid resin and polyurethane resin as a main component is preferred.

[0389] Here, "main component" refers to the component with the largest weight ratio among the components constituting the components of the image display device, specifically, it accounts for more than 50% by weight of the resin composition (resin sheet) forming the components of the image display device, more preferably more than 55% by weight, and particularly preferably more than 60% by weight.

[0390] <Method for producing laminate for image display device>

[0391] There is no particular limitation on the method for producing the laminate for the image display device. For example, as described above, the adhesive composition can be applied to the image display device components to form an adhesive sheet, or an adhesive sheet with a release film can be formed in advance and then bonded to the image display device components.

[0392] <<Image display device>>

[0393] An image display device of an example of an embodiment of the present invention (hereinafter, sometimes referred to as "the present image display device") is an image display device incorporating an image display device laminate, wherein the image display device laminate has a structure in which two image display device constituent members are laminated with the present adhesive sheet sandwiched therebetween. For example, the present image display device having the laminate having the structure in which two image display device constituent members are laminated with the present adhesive sheet sandwiched therebetween can be formed by laminating the image display device laminate having the structure in which two image display device constituent members are laminated with the present adhesive sheet sandwiched therebetween on other image display device constituent members.

[0394] Example

[0395] Hereinafter, an example of an embodiment of the present invention will be described in detail, but the present invention is not limited to the embodiment described below.

[0396] First, the raw materials of the adhesive compositions prepared in Examples are described in detail.

[0397] <(Meth)acrylic acid polymer (A)>

[0398] (Meth)acrylic polymer (A-1): an acrylic copolymer prepared by random copolymerization of 46.4 parts by mass of 2-ethylhexyl acrylate, 45.1 parts by mass of methyl acrylate and 8.5 parts by mass of N-vinyl-2-pyrrolidone (weight average molecular weight: about 230,000).

[0399] (Meth)acrylic polymer (A-2): an acrylic copolymer prepared by random copolymerization of 64.0 parts by mass of 2-ethylhexyl acrylate, 19.0 parts by mass of methyl acrylate and 17.0 parts by mass of hydroxyethyl acrylate (weight average molecular weight: about 460,000).

[0400] <Photoinitiator (B)>

[0401] Photoinitiator (b1-1): a photoinitiator having a glyoxylate structure represented by the following formula 3-1 (molar absorption coefficient at a wavelength of 405 nm: 3.3×10 2 L / mol·cm)

[0402]

[0403] Photoinitiator (b2-1): a mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone ("Esacure TZT" manufactured by IGM, molar absorption coefficient at a wavelength of 405 nm: 0 L / mol·cm)

[0404] Photoinitiator (b2-2): methyl benzoylformate ("Omnirad MBF" manufactured by IGM, molar absorption coefficient at a wavelength of 405 nm: 6.5 L / mol·cm)

[0405] Photoinitiator (b2-3): 2,4-diethylthioxanthone ("Omnirad DETX" manufactured by IGM, molar absorption coefficient at wavelength 405 nm: 3.3 × 10 3 L / mol·cm)

[0406] Photoinitiator (b2-4): ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate ("Omnirad TPO-L" manufactured by IGM, molar absorption coefficient at a wavelength of 405 nm: 81 L / mol·cm)

[0407] <Ultraviolet absorber (C)>

[0408] Ultraviolet light absorber (C-1): bis-ethylhexyloxyphenol methoxyphenyl triazine (Tinosorb S, manufactured by BASF Japan Co., Ltd.)

[0409] <Multifunctional (meth)acrylate (D)>

[0410] · Multifunctional (meth)acrylate (D-1): polypropylene glycol #400 diacrylate (NK ESTER APG-400, manufactured by Shin-Nakamura Chemical Co., Ltd.)

[0411] · Multifunctional (meth)acrylate (D-2): Propylene oxide-modified pentaerythritol tri(tetra)acrylate (NKESTER ATM-4PL, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0412] · Multifunctional (meth)acrylate (D-3): pentaerythritol tri(tetra)acrylate (NK ESTER ATMM3L, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0413] [Example A1]

[0414] 100 parts by mass of the (meth)acrylic polymer (A-1) and 1.5 parts by mass of the photoinitiator (B-1) were uniformly mixed to prepare an adhesive composition.

[0415] The pressure-sensitive adhesive composition was spread out in a sheet form on a 100 μm thick release film (PET film manufactured by Mitsubishi Chemical Group Corporation) subjected to silicone release treatment so as to have a thickness of 100 μm.

[0416] Next, a 75 μm thick release film (PET film manufactured by Mitsubishi Chemical Group Corporation) treated with silicone release was laminated on the sheet-like PSA composition to form a laminate, thereby obtaining a PSA sheet with a release film consisting of release film / PSA sheet / release film.

[0417] Next, a 405 nm LED light source (FireJet FJ200 405 nm) was used to irradiate both surfaces of the adhesive sheet with a release film at 1000 mJ / cm 2 The adhesive sheet was semi-cured by irradiating both surfaces with light having a peak wavelength of 405 nm through the release film. The accumulated light quantity was measured using an ultraviolet accumulated light quantity meter "UIT-250" (manufactured by Ushio Inc.) and a light receiver "UVD-C405" (manufactured by Ushio Inc.) (the same applies hereinafter).

[0418] The obtained release film-attached pressure-sensitive adhesive sheet has an active energy ray-curable pressure-sensitive adhesive sheet.

[0419] [Example A2, Comparative Examples A1 to A4]

[0420] A PSA sheet with a release film was prepared in the same manner as in Example 1 except that the PSA composition was changed to the formulation shown in Table 1.

[0421] [Physical property measurement and evaluation]

[0422] The following various measurements and evaluations were performed on the PSA sheets produced in the Examples and Comparative Examples. The evaluation results are summarized in Tables 1 and 2.

[0423] <Gel ratio>

[0424] For the adhesive sheet with release film prepared in the embodiments and comparative examples, about 0.1g of the adhesive sheet is extracted from the adhesive sheet obtained by peeling off the release film. The extracted adhesive sheet is wrapped in a SUS mesh (#150) of mass X (g) pre-made into a bag, and the bag mouth is sealed as a sample, and the mass Y (g) of the sample is measured. After the aforementioned sample is immersed in ethyl acetate and stored at 23°C in a dark place for 24 hours, the aforementioned sample is taken out and heated at 70°C for 4.5 hours to evaporate the ethyl acetate, and the mass Z (g) of the dried sample is measured. Based on the measured masses, the gel fraction (X0) after the first curing is calculated using the following formula.

[0425] Gel fraction (%) = [(Z-X) / (Y-X)] × 100

[0426] In addition, the pressure-sensitive adhesive sheets with release films prepared in the examples and comparative examples were illuminated using a 405 nm LED light source (FireJet FJ200 405 nm) at a cumulative light intensity of 3000 mJ / cm 2 The adhesive sheet was cured by irradiating light having a peak wavelength of 405 nm through the release film. The cured adhesive sheet was used to calculate the gel fraction (X1) after secondary curing in the same manner as the gel fraction (X0).

[0427] <Chroma>

[0428] The release film of the adhesive sheet with release film prepared in the examples and comparative examples was peeled off, and the exposed double-sided adhesive surface was sandwiched between two sheets of soda lime glass (thickness 0.55 mm) to prepare a bonding sample. The chromaticity (b*0) after primary curing was measured using a spectrophotometer (Suga Test Instruments Co., Ltd.) "SC-T" according to JIS K7103, using a D65 light source and a 10° field of view.

[0429] In addition, the pressure-sensitive adhesive sheets with release films prepared in the examples and comparative examples were illuminated using a 405 nm LED light source (FireJet FJ200 405 nm) at a cumulative light intensity of 3000 mJ / cm 2 The adhesive sheet was cured by irradiating light having a peak wavelength of 405 nm through the release film. The chromaticity (b*1) after secondary curing was measured using the cured adhesive sheet in the same manner as the chromaticity (b*0).

[0430] When the chromaticity (b*1) after the secondary curing was 2.5 or less, it was determined that there was no problem in practical use.

[0431] <Light transmittance>

[0432] The release film on one side of the adhesive sheet with release film prepared in the examples and comparative examples was peeled off, and the exposed adhesive surface was roll-bonded to a soda-lime glass (82mm×53mm×thickness 0.5mm). Then, the remaining release film was peeled off, and the exposed adhesive surface was roll-bonded to another soda-lime glass (82mm×53mm×thickness 0.5mm). Thereafter, an autoclave treatment (60°C, gauge pressure 0.2MPa, 20 minutes) was performed for final bonding, and a 405nm LED light source (FireJet FJ200 405nm) was used to achieve a cumulative light intensity of 3000mJ / cm 2 The adhesive sheet was cured by irradiating light having a peak wavelength of 405 nm to prepare a laminate for evaluation.

[0433] The evaluation laminate was measured for spectral transmittance (%) at wavelengths of 300 nm to 800 nm using a spectrophotometer (UV2000 manufactured by Shimadzu Corporation), and the transmittance at wavelengths of 380 nm and 400 nm was determined.

[0434] <Adhesion>

[0435] The release film on one side of the release film-attached pressure-sensitive adhesive sheet produced in Examples and Comparative Examples was peeled off, and a 100 μm thick polyethylene terephthalate film (“COSMOSHINEA 4300” manufactured by TOYOBO CO., LTD.) was bonded thereto as a liner film to prepare a laminated product.

[0436] After the laminated product was cut into pieces of 150 mm in length and 10 mm in width, the remaining release film was peeled off, and the exposed adhesive surface was brought into contact with the soda lime glass. The roller was reciprocated once to roll the adhesive sheet. The obtained laminated product was aged at 60°C for 30 minutes for final bonding, and then a 405 nm LED light source (FireJet FJ200 405 nm) was used to achieve a cumulative light intensity of 3000 mJ / cm 2 The adhesive sheet was cured by irradiating light through the liner film in a manner of , and aged at 23° C. for 15 hours to prepare a sample for adhesive strength measurement.

[0437] The adhesive strength test sample was peeled off at 23° C. and 40% RH at a peeling angle of 180° and a peeling speed of 60 mm / min to measure the peeling force (N / cm) on glass to determine the adhesive strength (P1) after secondary curing.

[0438] [Table 1]

[0439]

[0440] The adhesive sheets of Examples A1 and A2 had sufficient curability for a 405 nm LED light source, and the chromaticity (b*) was also controlled to a value within the standard, which was a suitable result.

[0441] On the other hand, the adhesive sheets of Comparative Examples A1 and A2 had poor curability with respect to a 405 nm LED light source. This is believed to be because the molar absorption coefficient of the photoinitiator used at a wavelength of 405 nm was low.

[0442] The adhesive sheet of Comparative Example A3 had poor curability with a 405 nm LED light source, and the chromaticity (b*) was not within the standard. This is believed to be because the b* increased due to light irradiation due to the characteristics of the photoinitiator.

[0443] The adhesive composition of Comparative Example A4 uses a cleavage-type photoinitiator, and therefore generates a photodecomposition product when irradiated with active energy rays.

[0444] In addition, the active energy ray curing property of the adhesive sheet of Comparative Example A4 was insufficient. This is believed to be because only a cleavage-type photoinitiator was used, and thus the photoinitiator was consumed by light irradiation during the production of the adhesive sheet, making it difficult to control the adhesive sheet to a state that allowed for curing by active energy rays, and the adhesive sheet lost its photocuring property.

[0445] [Example B1]

[0446] 100 parts by mass of the (meth)acrylic polymer (A-1), 1.5 parts by mass of the photoinitiator (b1-1), 1.4 parts by mass of the ultraviolet absorber (C-1), and 1.5 parts by mass of the polyfunctional (meth)acrylate (D-1) were uniformly mixed to prepare an adhesive composition.

[0447] The pressure-sensitive adhesive composition was spread out in a sheet form on a 100 μm thick release film (PET film manufactured by Mitsubishi Chemical Group Corporation) subjected to silicone release treatment so as to have a thickness of 100 μm.

[0448] Next, a 75 μm thick release film (PET film manufactured by Mitsubishi Chemical Group Corporation) treated with silicone release was laminated on the sheet-like PSA composition to form a laminate, thereby obtaining a PSA sheet with a release film consisting of release film / PSA sheet / release film.

[0449] Next, a 405 nm LED light source (FireJet FJ200 405 nm) was used to irradiate both surfaces of the adhesive sheet with a release film at 1000 mJ / cm 2 (Cumulative light intensity 2000mJ / cm 2 ) was applied to both surfaces through the release film to irradiate light having a peak wavelength of 405 nm to semi-cure the adhesive sheet. The accumulated light quantity was measured using an ultraviolet accumulated light quantity meter "UIT-250" (manufactured by Ushio Inc.) and a light receiver "UVD-C405" (manufactured by Ushio Inc.) (the same applies hereinafter).

[0450] The obtained release film-attached pressure-sensitive adhesive sheet has an active energy ray-curable pressure-sensitive adhesive sheet.

[0451] [Example B2]

[0452] A PSA sheet with a release film was prepared in the same manner as in Example B1 except that the PSA composition was changed to the formulation shown in Table 2.

[0453] [Example B3]

[0454] 100 parts by mass of a (meth)acrylic polymer (A-1), 1.5 parts by mass of a photoinitiator (b1-1), 1.2 parts by mass of a UV absorber (C-1), and 1.5 parts by mass of a polyfunctional (meth)acrylate (D-1) were uniformly mixed to prepare an adhesive composition.

[0455] The pressure-sensitive adhesive composition was spread out in a sheet form on a 100 μm thick release film (PET film manufactured by Mitsubishi Chemical Group Corporation) subjected to silicone release treatment so as to have a thickness of 100 μm.

[0456] Next, a 75 μm thick release film (PET film manufactured by Mitsubishi Chemical Group Corporation) treated with silicone release was laminated on the sheet-like PSA composition to form a laminate, thereby obtaining a PSA sheet with a release film consisting of release film / PSA sheet / release film.

[0457] Next, a metal halide lamp was used to illuminate one side of the adhesive sheet with a release film at a wavelength of 405 nm with a cumulative light intensity of 2000 mJ / cm 2 In this way, both surfaces are irradiated with light through the release film to semi-cure the adhesive sheet.

[0458] The obtained release film-attached pressure-sensitive adhesive sheet has an active energy ray-curable pressure-sensitive adhesive sheet.

[0459] [Examples B4 and B5]

[0460] A PSA sheet with a release film was prepared in the same manner as in Example B3 except that the formulation of the PSA composition and the light irradiation conditions were changed as shown in Table 2.

[0461] [Comparative Examples B1 to B3]

[0462] A PSA sheet with a release film was prepared in the same manner as in Example B1 except that the PSA composition was changed to the formulation shown in Table 2.

[0463] [Table 2]

[0464]

[0465] The adhesive sheets of Examples B1 to B5 had sufficient curability for a 405 nm LED light source, and the chromaticity (b*) was also controlled to a value within the standard, which was a suitable result.

[0466] On the other hand, the adhesive sheets of Comparative Examples B1 and B2 had poor curability with respect to a 405 nm LED light source. This is probably because the molar absorption coefficient of the photoinitiator used at a wavelength of 405 nm was low.

[0467] The adhesive composition of Comparative Example B3 uses a cleavage-type photoinitiator, and therefore generates a photodecomposition product when irradiated with active energy rays.

[0468] In addition, the adhesive sheet of Comparative Example B3 is compounded with 10 parts by mass of a multifunctional (meth)acrylate (D). Therefore, when the adhesive sheet is manufactured, the reaction of the multifunctional (meth)acrylate (D) proceeds rapidly due to light irradiation, and the gel fraction (X0) becomes larger. In addition, the difference in gel fraction (X1-X0) is small, and the room for curing using active energy rays is reduced.

Claims

1. An adhesive composition comprising a (meth)acrylic polymer A and a photoinitiator B, The photoinitiator B comprises a photoinitiator b1, wherein the photoinitiator b1 has a glyoxylate structure represented by the following formula 1 and has a molar absorption coefficient of 30 L / mol·cm or more at a wavelength of 405 nm. In Formula 1, R 1 is substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C3~C 20 Cycloalkyl or substituted or unsubstituted C2~C 20 Heterocycloalkyl, * represents a connecting bond.

2. An adhesive composition comprising a (meth)acrylic polymer A, a photoinitiator B and an ultraviolet absorber C, The photoinitiator B comprises a photoinitiator b1, wherein the photoinitiator b1 has a glyoxylate structure represented by the following formula 1 and has a molar absorption coefficient of 30 L / mol·cm or more at a wavelength of 405 nm. In Formula 1, R 1 is substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C3~C 20 Cycloalkyl or substituted or unsubstituted C2~C 20 Heterocycloalkyl, * represents a connecting bond.

3. The adhesive composition according to claim 1 or 2, wherein The photoinitiator b1 is a compound including a biphenyl structure bonded by a connecting bond * in Formula 1.

4. The adhesive composition according to claim 1 or 2, wherein The photoinitiator b1 is a compound including a sulfide biphenyl structure bonded by a connecting bond * in Formula 1.

5. The adhesive composition according to claim 1 or 2, wherein The photoinitiator b1 is a compound having two or more free radical generating groups in the molecule. The adhesive composition according to claim 1 or 2, further comprising a multifunctional (meth)acrylate D.

7. The adhesive composition according to claim 6, wherein The content of the polyfunctional (meth)acrylate D is 0.1 parts by mass or more and 20 parts by mass or less based on 100 parts by mass of the (meth)acrylic polymer A.

8. The adhesive composition according to claim 1 or 2, wherein The (meth)acrylic polymer A comprises: a structural unit derived from an alkyl (meth)acrylate having a linear or branched alkyl group with 3 to 30 carbon atoms; and a structural unit derived from a hydroxyl group-containing monomer and / or a structural unit derived from a nitrogen-containing monomer. 9 . A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to claim 1 . 10 . The pressure-sensitive adhesive sheet according to claim 9 , which has a light transmittance of 10% or less at a wavelength of 380 nm. 11 . The pressure-sensitive adhesive sheet according to claim 9 , which has a light transmittance of 30% or less at a wavelength of 400 nm. 12 . The adhesive sheet according to claim 9 , which has a total light transmittance of 80% or more. 13 . The pressure-sensitive adhesive sheet according to claim 9 , wherein the gel fraction X0 is 20% or more.

14. The adhesive sheet according to claim 13, wherein The adhesive sheet has active energy ray curability, and the accumulated light intensity of the adhesive sheet is 2000 to 4000 mJ / cm 2 The gel fraction X1 when irradiated with active energy rays having a wavelength of 405 nm is 30% or more.

15. The adhesive sheet according to claim 14, wherein A difference X1-X0 between the gel fraction X1 and the gel fraction X0 is 2% or more.

16. The adhesive sheet according to claim 9, wherein The adhesive sheet has active energy ray curability, and the adhesive sheet is exposed to an accumulated light amount of 2000 to 4000 mJ / cm 2 The chromaticity b*1 when irradiated with active energy rays having a wavelength of 405 nm is 2.5 or less, and the difference b*1-b*0 from the chromaticity b*0 before the active energy ray irradiation is 1.0 or less. The pressure-sensitive adhesive sheet according to claim 9 , which is used for bonding optical components. 18 . A pressure-sensitive adhesive sheet with a release film, comprising a structure in which the pressure-sensitive adhesive sheet according to claim 9 and a release film are laminated. 19 . A laminate for an image display device, comprising a structure in which two optical members are laminated with the pressure-sensitive adhesive sheet according to claim 9 interposed therebetween. 20 . An image display device comprising the laminate for an image display device according to claim 19 . 21 . An adhesive sheet for an organic EL display device, comprising the adhesive sheet according to claim 9 .

22. An adhesive sheet comprising an adhesive layer formed from an adhesive composition containing a (meth)acrylic polymer A and a photoinitiator B, The photoinitiator B comprises a compound represented by the following formula 2: In Formula 2, A is O, S, NR 4 or a linear or branched alkylene or cycloalkylene group having 1 to 6 carbon atoms, R 1 is substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C3~C 20 Cycloalkyl or substituted or unsubstituted C2~C 20 Heterocycloalkyl, R 2 is a hydrogen atom, a substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C3~C 20 Cycloalkyl, substituted or unsubstituted C2~C 20 Heterocycloalkyl, substituted or unsubstituted C6~C 20 Aryl, substituted or unsubstituted C1~C 20 Heteroaryl, SR 5 , OR 6 NR 7 R 8 、C(O)R 9 or C(O)OR 13 , R 4 is selected from hydrogen atom, C1~C 18 Alkyl, C2~C 18 Alkanoyl, C6~C 10 Aryl and C7~C 11 Aroyl radicals in the group consisting of R 5 and R 6 are independently selected from a hydrogen atom, a C1-C 20 Alkyl, C2~C 20 Alkanoyl, C6~C 10 Aryl and C7~C 11 Aroyl radicals in the group consisting of R 7 and R 8 are independently selected from a hydrogen atom, a C1-C 20 Alkyl, C2~C 20 Alkanoyl, C7~C 11 Aroyl, C6~C 10 The group consisting of aromatic groups, R 9 is selected from hydrogen atom, C1~C 20 Alkyl and C6~C 20 The group consisting of aromatic groups, R 13 With R 1 Same meaning.

23. An adhesive sheet comprising an adhesive layer formed from an adhesive composition containing a (meth)acrylic polymer A, a photoinitiator B and an ultraviolet absorber C, The photoinitiator B comprises a compound represented by the following formula 2: In Formula 2, A is O, S, NR 4 or a linear or branched alkylene or cycloalkylene group having 1 to 6 carbon atoms, R 1 is substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C3~C 20 Cycloalkyl or substituted or unsubstituted C2~C 20 Heterocycloalkyl, R 2 is a hydrogen atom, a substituted or unsubstituted C1~C 20 Alkyl, substituted or unsubstituted C3~C 20 Cycloalkyl, substituted or unsubstituted C2~C 20 Heterocycloalkyl, substituted or unsubstituted C6~C 20 Aryl, substituted or unsubstituted C1~C 20 Heteroaryl, SR 5 , OR 6 NR 7 R 8 、C(O)R 9 or C(O)OR 13 , R 4 is selected from hydrogen atom, C1~C 18 Alkyl, C2~C 18 Alkanoyl, C6~C 10 Aryl and C7~C 11 Aroyl radicals in the group consisting of R 5 and R 6 are independently selected from a hydrogen atom, a C1-C 20 Alkyl, C2~C 20 Alkanoyl, C6~C 10 Aryl and C7~C 11 Aroyl radicals in the group consisting of R 7 and R 8 are independently selected from a hydrogen atom, a C1-C 20 Alkyl, C2~C 20 Alkanoyl, C7~C 11 Aroyl, C6~C 10 The group consisting of aromatic groups, R 9 is selected from hydrogen atom, C1~C 20 Alkyl and C6~C 20 The group consisting of aromatic groups, R 13 With R 1 Same meaning.

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