Composition, adhesive, and adhesive sheet

Abstract

To provide a composition capable of forming an adhesive layer that excels in both of adhesive power and retentive power.SOLUTION: A composition contains: a polymer A containing a constitutional unit derived from a monomer M having a structure to produce activity species by light excitation; and a compound a containing two or more constitutional units derived from a monomer of the following formula and having a radical-polymerizable group at an end, where X is a hydrogen atom or a methyl group, Y is a group having a structure to produce activity species by light excitation, a C2-16 alkyl group, an alicyclic group, an aryl group, a heteroaryl group, an aralkyl group, an alkaryl group, an organosilyl group, or a (poly)organosiloxane group.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a composition that is effective for improving the adhesive strength, holding power, and other performance properties of a pressure-sensitive adhesive, and to a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet that contain the composition. [Background technology]

[0002] Pressure-sensitive adhesives using compositions containing polymers, compounds, etc. are used for various applications such as adhesive tapes, pressure-sensitive adhesives, hot melt adhesives, etc., depending on the purpose. Patent Document 1 discloses a pressure-sensitive adhesive containing such a composition, which has a specific structure in the polymer main chain, contains a block copolymer having a weight average molecular weight / number average molecular weight ratio within a specific range, and a specific diblock copolymer, in which the weight ratio of the block copolymer to the diblock copolymer is within a specific range, and has a melt viscosity of a predetermined value or less.

[0003] Furthermore, Patent Document 2 discloses an example of a pressure-sensitive adhesive composition that uses an acrylic block copolymer for the purpose of improving adhesiveness and holding power at high temperatures. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-323072 [Patent Document 2] JP 2010-106230 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the adhesive described in Patent Document 1 has excellent holding power, but does not fully express the adhesive power. Also, the adhesive described in Patent Document 2 aims to improve both adhesive power and holding power, but it is difficult to say that it has sufficiently improved both performances.

[0006] Therefore, an object of the present invention is to provide a pressure-sensitive adhesive having excellent performance in both adhesive strength and holding power, and a composition that can be used for a pressure-sensitive adhesive having excellent performance in both adhesive strength and holding power. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A composition comprising: a polymer A containing a structural unit derived from a monomer M capable of forming a new bond upon photoexcitation; and a compound a containing two or more structural units derived from a monomer m represented by formula (1) and having a radical polymerizable group at its end.

[0008] [ka] (1) (In the formula, X represents a hydrogen atom or a methyl group, and Y represents a group having a structure that generates an active species upon photoexcitation, an unsubstituted or substituted alkyl group having 2 to 16 carbon atoms, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, an unsubstituted or substituted organosilyl group, or an unsubstituted or substituted (poly)organosiloxane group. The substituents in these groups are at least one selected from the group consisting of alkyl groups, aryl groups, heteroaryl groups, non-aromatic heterocyclic groups, aralkyl groups, alkaryl groups, carboxylic acid groups, carboxylate groups, epoxy groups, hydroxy groups, alkoxy groups, primary amino groups, secondary amino groups, tertiary amino groups, isocyanato groups, sulfonic acid groups, and halogen atoms.) [2] The composition described in [1], wherein the new bond is a cross-linked structure. [3] The composition according to [2], wherein the monomer M generates an active species upon photoexcitation and forms the crosslinked structure. [4] The composition according to [3], wherein the active species is a radical. [5] The composition according to any one of [1] to [4], wherein the compound a has a glass transition temperature of −100° C. or higher and 100° C. or lower. [6] The composition according to any one of [1] to [5], wherein the monomer M has a structure of formula (2).

[0009] [ka] (2) (In the formula, R A , R B each independently represents an alkyl group, a carboxy group, or a halogen atom, n represents an integer of 0 to 5, m represents an integer of 0 to 4, and X represents a (meth)acryloyloxy group or a (meth)acryloyloxyalkyleneoxy group. [7] The composition according to any one of [1] to [6], wherein the content of the structural unit derived from the monomer M is 0.01% by mass or more and 50% by mass or less, relative to the total mass of the composition (100% by mass). [8] The composition according to any one of [1] to [7], wherein the polymer A has a glass transition temperature of 0° C. or lower. [9] The composition according to any one of [1] to [8], wherein a ratio of the compound a to the polymer A is 0.1:99.9 to 30:70.

[10] The composition according to any one of [1] to [9], wherein the compound a has a structure represented by formula (3).

[0010] [ka] (3) (In the formula, R is a group having a structure that generates an active species by photoexcitation, or a linear or branched alkyl group having 1 to 30 carbon atoms, Z is a terminal group, and R 21 represents a hydrogen atom or a methyl group, R 22represents a group having a structure that generates an active species upon photoexcitation, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, an unsubstituted or substituted organosilyl group, or an unsubstituted or substituted (poly)organosiloxane group, each of which is at least one selected from the group consisting of an alkyl group, an aryl group, a heteroaryl group, a non-aromatic heterocyclic group, an aralkyl group, an alkaryl group, a carboxylic acid group, a carboxylate group, an epoxy group, a hydroxy group, an alkoxy group, a primary amino group, a secondary amino group, a tertiary amino group, an isocyanato group, a sulfonic acid group, and a halogen atom, and n represents a natural number of 2 or more. The terminal group in Z is a hydrogen atom or a group derived from a radical polymerization initiator.)

[11] The composition according to any one of [1] to

[10] , wherein the polymer A comprises a (meth)acrylic copolymer.

[12] A pressure-sensitive adhesive obtained by irradiating the composition according to any one of [1] to

[11] with ultraviolet light.

[13] A pressure-sensitive adhesive comprising the composition according to any one of [1] to

[11] .

[14] An adhesive sheet comprising the adhesive according to

[12] or

[13] . Effect of the Invention

[0011] According to the present invention, a pressure-sensitive adhesive having excellent adhesion and holding power can be provided. Also, according to the present invention, a composition usable for a pressure-sensitive adhesive having excellent adhesion and holding power can be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The following describes in detail an embodiment of the present invention. However, the following description is an example of an embodiment of the present invention, and the present invention is not limited to the contents of the following description as long as it does not go beyond the gist of the present invention. In this specification, when the expression "~" is used, it is used as an expression including the numerical value or physical property value before and after it. Furthermore, in the present invention, when the expression "(meth)acrylic" is used, it means one or both of "acrylic" and "methacrylic". The same applies to "(meth)acrylate", "(meth)acryloyl", etc.

[0013] A composition according to one embodiment of the present invention (hereinafter also referred to as "the composition") comprises a polymer A containing two or more structural units derived from a monomer M capable of forming a new bond upon photoexcitation, and a compound a containing two or more structural units derived from a monomer m represented by formula (1) and having a radical polymerizable group at its end.

[0014] [ka] (1) (In the formula, X represents a hydrogen atom or a methyl group, and Y represents a group having a structure that generates an active species upon photoexcitation, an unsubstituted or substituted alkyl group having 2 to 16 carbon atoms, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, an unsubstituted or substituted organosilyl group, or an unsubstituted or substituted (poly)organosiloxane group. The substituents in these groups are at least one selected from the group consisting of alkyl groups, aryl groups, heteroaryl groups, non-aromatic heterocyclic groups, aralkyl groups, alkaryl groups, carboxylic acid groups, carboxylate groups, epoxy groups, hydroxy groups, alkoxy groups, primary amino groups, secondary amino groups, tertiary amino groups, isocyanato groups, sulfonic acid groups, and halogen atoms.)

[0015] In the present composition, the compound a and the polymer A, or multiple polymers A form a crosslinked structure by photoexcitation, thereby improving the cohesive strength of the composition. The crosslinked structure may be formed by photoexcitation to generate an active species (radical) in the radical polymerizable group at the end of the compound a, thereby forming a new bond between the compound a and the polymer A, or by photoexcitation to generate an active species in a structural unit derived from the monomer M, thereby forming a new bond between the compound a and the polymer A, or between multiple polymers A. In addition, photoexcitation may generate an active species in the radical polymerizable group at the end of the compound a, thereby forming a crosslinked structure between another compound a.

[0016] The radical polymerizable group is preferably a group having an ethylenically unsaturated bond. Examples of the group having an ethylenically unsaturated bond include CH2=C(COOR)-CH2-, a (meth)acryloyl group, a 2-(hydroxymethyl)acryloyl group, and a vinyl group. Here, R represents a hydrogen atom, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, or an unsubstituted or substituted heterocyclic group.

[0017] [Polymer A] Polymer A is a polymer containing a structural unit derived from monomer M that can form a new bond by photoexcitation. Monomer M has a structure that can generate active species (radicals) when irradiated with light such as ultraviolet light and form a new bond with other molecules. In other words, the structural unit derived from monomer M has the function of forming a cross-linked structure between molecules by forming a new bond with other molecules by photoexcitation. Here, cross-linking is a process in which atoms in a polymer are chemically bonded to each other to form a bridge structure within or between molecules, and a structure formed by chemical bonding through cross-linking is called a cross-linked structure.

[0018] Examples of the structure that generates active species contained in the monomer M include a benzophenone skeleton, a thioxanthone skeleton, and an anthraquinone skeleton. By using a polymer containing a structural unit derived from the monomer M having a structure that generates active species by photoexcitation in the present composition, it is possible to form a crosslinked structure by ultraviolet irradiation or the like, resulting in a composition with excellent adhesion, holding power, and substrate contamination resistance. In addition, a pressure-sensitive adhesive containing such a composition exhibits excellent adhesion, holding power, and substrate contamination resistance.

[0019] Furthermore, from the viewpoint of adhesive properties, polymer A is preferably a (meth)acrylic copolymer. The (meth)acrylic copolymer refers to a copolymer in which at least a part of the constituent units is derived from a (meth)acrylic monomer. The (meth)acrylic copolymer may further contain a constituent unit derived from a monomer other than the (meth)acrylic monomer (e.g., styrene, etc.). The (meth)acrylic monomer means a monomer having a (meth)acryloyl group, and examples thereof include the same (meth)acrylic monomers as the monomer m described below. Furthermore, the glass transition temperature (Tg) of the (meth)acrylic copolymer is preferably 0° C. or lower, more preferably −5° C. or lower, from the viewpoint of adhesion.

[0020] In addition, the (meth)acrylic copolymer preferably contains a structural unit derived from a carboxy group-containing (meth)acrylic monomer, since this improves adhesive strength. The content of the structural units derived from the carboxy group-containing (meth)acrylic monomer relative to the total mass of the (meth)acrylic copolymer is preferably 0.1 to 20 mass%, more preferably 0.3 to 15 mass%, and even more preferably 0.5 to 10 mass%. Examples of the carboxy group-containing (meth)acrylic monomer 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, and 2-(meth)acryloyloxypropyl succinic acid.

[0021] The weight average molecular weight (Mw) of polymer A measured by gel permeation chromatography (GPC) is preferably 5000 to 2000000, more preferably 10000 to 1000000, and even more preferably 30000 to 350000. When the Mw is equal to or more than the lower limit, the adhesive layer has excellent durability, and when the Mw is equal to or less than the upper limit, the adhesive layer has excellent handleability (compatibility with other components, coatability, hot melt processability, etc.).

[0022] The glass transition temperature of the polymer A is preferably 0° C. or lower, more preferably −10° C. or lower, from the viewpoint of melt viscosity. The glass transition temperature (Tg) is a value calculated by the following formula, converted from absolute temperature (K) to Celsius (°C). 1 / Tg=Σ(wi / Tgi) In the above formula, wi represents the mass fraction of monomer i constituting the polymer, and Tgi represents the glass transition temperature of a homopolymer of monomer i constituting the polymer. In the above formula, Tg and Tgi are values ​​expressed in absolute temperature (K). The glass transition temperature of the homopolymer of monomer i is the value described in Polymer Handbook [Polymer Handbook, J. Brandrup, Interscience, 1989].

[0023] The polymer A can be produced by a known method using a known polymerization initiator. As the polymerization method, for example, a known polymerization method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, an emulsion polymerization method, etc. can be applied, and the solution polymerization method is preferable.

[0024] [Monomer M] The monomer M is a monomer having a structure that generates an active species upon photoexcitation. Examples of monomers having a structure that generates active species upon photoexcitation include monomers having a benzophenone skeleton, a thioxanthone skeleton, an anthraquinone skeleton, etc., and in particular, a benzophenone derivative represented by the following formula (2) is preferred in terms of reactivity.

[0025] [ka] (2) (In the formula, R A , R B each independently represents an alkyl group, a carboxy group, or a halogen atom, n represents an integer of 0 to 5, m represents an integer of 0 to 4, and X represents a (meth)acryloyloxy group or a (meth)acryloyloxyalkyleneoxy group.

[0026] In terms of balancing the performance, the content of the monomer M-derived structural unit in the present composition is preferably 0.01% by mass or more and 50% by mass or less, more preferably 0.03% by mass or more and 40% by mass or less, even more preferably 0.05% by mass or more and 30% by mass or less, and most preferably 0.1% by mass or more and 10% by mass or less, relative to the total mass 100% of the composition. When the content of the monomer M-derived structural unit is higher than the lower limit, the holding power of the composition is improved. Also, when the content of the monomer M-derived structural unit is lower than the upper limit, the compatibility with other components is improved.

[0027] [Monomer m] Monomer m is a monomer having a structure represented by formula (1).

[0028] [ka] (1) (In the formula, X represents a hydrogen atom or a methyl group, and Y represents a group having a structure that generates an active species upon photoexcitation, an unsubstituted or substituted alkyl group having 2 to 16 carbon atoms, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, an unsubstituted or substituted organosilyl group, or an unsubstituted or substituted (poly)organosiloxane group. The substituents in these groups are at least one selected from the group consisting of alkyl groups, aryl groups, heteroaryl groups, non-aromatic heterocyclic groups, aralkyl groups, alkaryl groups, carboxylic acid groups, carboxylate groups, epoxy groups, hydroxy groups, alkoxy groups, primary amino groups, secondary amino groups, tertiary amino groups, isocyanato groups, sulfonic acid groups, and halogen atoms.)

[0029] Examples of the monomer m include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, hexadecyl (meth)acrylate, and nonaphthalene (meth)acrylate. Hydrocarbon group-containing (meth)acrylates such as isononyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, 3,5,5-trimethylcyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, terpene acrylates and derivatives thereof, hydrogenated rosin acrylates and derivatives thereof, and docosyl (meth)acrylate. p) Acrylic acid esters; hydroxyl group-containing (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and glycerol (meth)acrylate; (meth)acrylic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyloxypropyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, acryloyloxypropyl phthalate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxypropyl maleate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxypropyl succinate, crotonic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, monomethyl maleate, monoethyl maleate, monooctyl maleate, monomethyl itaconate, monoethyl itaconate, monobutyl itaconate, monooctyl itaconate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate,Carboxyl group-containing vinyl monomers such as monooctyl fumarate and monoethyl citraconic acid; acid anhydride group-containing vinyl monomers such as maleic anhydride and itaconic anhydride; unsaturated dicarboxylic acid diester monomers such as dimethyl maleate, dibutyl maleate, dimethyl fumarate, dibutyl fumarate, dibutyl itaconate, and diperfluorocyclohexyl fumarate; epoxy group-containing vinyl monomers such as glycidyl (meth)acrylate, α-ethyl glycidyl acrylate, and 3,4-epoxybutyl (meth)acrylate; dimethylaminoethyl (meth)acrylate. vinyl monomers containing an amino group such as (meth)acrylic acid ester, diethylaminoethyl (meth)acrylate, etc.; vinyl monomers containing an amide group such as (meth)acrylamide, Nt-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-isopropylacrylamide, hydroxyethyl acrylamide, N-methoxymethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, diacetone acrylamide, maleic acid amide, maleimide, etc.; styrene, α-methylstyrene, vinyl toluene, (meth)acrylamide, Vinyl monomers such as acrylonitrile, vinyl acetate, and vinyl propionate; divinylbenzene, ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate. , polyfunctional vinyl monomers such as neopentyl glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, allyl (meth)acrylate, triallyl cyanurate, diallyl maleate, polypropylene glycol diallyl ether, and N,N'-methylenebis(meth)acrylamide; acryloylmorpholine,Polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, isobutoxyethyl (meth)acrylate, t-butoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, nonylphenoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, acetoxyethyl (meth)acrylate, "Placcel (registered trademark; the same applies hereinafter) (Product name: Caprolactone addition monomer, manufactured by Daicel Chemical Industries, Ltd.), "Blenmer (registered trademark, the same applies below) PME-100" (Product name: Methoxy polyethylene glycol methacrylate (having 2 ethylene glycol chains), manufactured by NOF Corp.), "Blenmer PME-200" (Product name: Methoxy polyethylene glycol methacrylate (having 4 ethylene glycol chains), manufactured by NOF Corp.), "Blenmer PME-400" (Product name: Methoxy polyethylene glycol methacrylate (having 9 ethylene glycol chains), manufactured by NOF Corp.) (trade name), "BLEMMER 50POEP-800B" (Octoxy polyethylene glycol-polypropylene glycol-methacrylate (having 8 ethylene glycol chains and 6 propylene glycol chains), trade name, manufactured by NOF Corp.) and "BLEMMER 20ANEP-600" (Nonylphenoxy (ethylene glycol-polypropylene glycol) monoacrylate, trade name, manufactured by NOF Corp.), "BLEMMER AME-100" (NOF Corp., trade name), "BLEMMER AME-200" (NOF Corp., trade name), and "BLEMMER 20ANEP-600" (Nonylphenoxy (ethylene glycol-polypropylene glycol) monoacrylate, trade name, manufactured by NOF Corp.) "Nomer 50AOEP-800B" (trade name, manufactured by NOF Corporation); trimethylsilyl (meth)acrylate, triethylsilyl (meth)acrylate, tri-n-propylsilyl (meth)acrylate, tri-n-butylsilyl (meth)acrylate, tri-n-amylsilyl (meth)acrylate, tri-n-hexylsilyl (meth)acrylate, tri-n-octylsilyl (meth)acrylate, tri-n-dodecylsilyl (meth)acrylate, triphenylsilyl (meth)acrylate, tri-p-methylphenylsilyl (meth)acrylate,Tribenzylsilyl (meth)acrylate, triisopropylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, tri(s-butyl)silyl (meth)acrylate, tri(2-methylisopropyl)silyl (meth)acrylate, tri(t-butyl)silyl (meth)acrylate, ethyldimethylsilyl (meth)acrylate, n-butyldimethylsilyl (meth)acrylate, diisopropyl(n-butyl)silyl (meth)acrylate, n-octyldi(n-butyl)silyl (meth)acrylate, diisopropyl Stearylsilyl (meth)acrylate, dicyclohexylphenylsilyl (meth)acrylate, t-butyldiphenylsilyl (meth)acrylate, lauryldiphenylsilyl (meth)acrylate, triisopropylsilyl methyl maleate, triisopropylsilyl amyl maleate, tri(n-butyl)silyl (n-butyl) maleate, (t-butyldiphenylsilyl) (methyl) maleate, (t-butyldiphenylsilyl) (n-butyl) maleate, (triisopropylsilyl) (methyl) fumarate, (triisopropylsilyl) (amyl) fumarate, myl) fumarate, (tri(n-butylsilyl))(n-butyl) fumarate, (t-butyldiphenylsilyl)(methyl) fumarate, (t-butyldiphenylsilyl)(n-butyl) fumarate, Silaplane FM-0711 (manufactured by JNC Corporation, trade name), Silaplane (registered trademark, the same applies below) FM-0721 (manufactured by JNC Corporation, trade name), Silaplane FM-0725 (manufactured by JNC Corporation, trade name), Silaplane TM-0701 (manufactured by JNC Corporation, trade name), Silaplane TM-0701T (manufactured by JNC Corporation, trade name), X- Organosilyl group-containing monomers other than silane coupling agent-containing monomers, such as 22-174ASX (Shin-Etsu Chemical Co., Ltd., trade name), X-22-174BX (Shin-Etsu Chemical Co., Ltd., trade name), KF-2012 (Shin-Etsu Chemical Co., Ltd., trade name), X-22-2426 (Shin-Etsu Chemical Co., Ltd., trade name), and X-22-2404 (Shin-Etsu Chemical Co., Ltd., trade name); halogenated olefins such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and chlorotrifluoroethylene; 2,2,2-trifluoroethyl (meth)acrylate,2,2,3,3,3-Pentafluorophenyl (meth)acrylate, 2-(perfluorobutyl)ethyl (meth)acrylate, 3-(perfluorobutyl)-2-hydroxypropyl (meth)acrylate, 2-(perfluorohexyl)ethyl (meth)acrylate, 3-perfluorohexyl-2-hydroxypropyl (meth)acrylate, 3-(perfluoro-3-methylbutyl)-2-hydroxypropyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, 1H,1H,2H,2H-trideca Fluorine-containing monomers (excluding halogenated olefins) such as fluorooctyl (meth)acrylate, 1H-1-(trifluoromethyl)trifluoroethyl (meth)acrylate, 1H,1H,3H-hexafluorobutyl (meth)acrylate, and 1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl (meth)acrylate; and monomers having an acetal structure such as 1-butoxyethyl (meth)acrylate, 1-(2-ethylhexyloxy)ethyl (meth)acrylate, 1-(cyclohexyloxy)ethyl methacrylate, and 2-tetrahydropyranyl (meth)acrylate.

[0030] [Compound a] Compound a is a compound that has a radically polymerizable group at its terminal and is therefore capable of forming a crosslinked structure with polymer A or another compound a.

[0031] Compound a is preferably a compound having a structure represented by the following formula (3).

[0032] [ka] (3) (In the formula, R is a group having a structure that generates an active species by photoexcitation, or a linear or branched alkyl group having 1 to 30 carbon atoms, Z is a terminal group, and R 21 represents a hydrogen atom or a methyl group, R 22represents a group having a structure that generates an active species by photoexcitation, an unsubstituted or substituted alkyl group, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, an unsubstituted or substituted organosilyl group, or an unsubstituted or substituted (poly)organosiloxane group, each of which is at least one selected from the group consisting of an alkyl group, an aryl group, a heteroaryl group, a non-aromatic heterocyclic group, an aralkyl group, an alkaryl group, a carboxylic acid group, a carboxylate group, an epoxy group, a hydroxyl group, an alkoxy group, a primary amino group, a secondary amino group, a tertiary amino group, an isocyanato group, a sulfonic acid group, and a halogen atom, and n represents a natural number of 2 or more. Z is a hydrogen atom or a group derived from a radical polymerization initiator.) The terminal group Z can be the same as the terminal group of a polymer obtained by known radical polymerization. Examples of structures that generate active species upon photoexcitation include a benzophenone skeleton, a thioxanthone skeleton, and an anthraquinone skeleton.

[0033] Compound a may be prepared by polymerizing a mixture of monomers including monomer m having a radical polymerizable group by a known method, such as a method using a cobalt chain transfer agent (U.S. Patent No. 4,680,352), a method using an α-substituted unsaturated compound such as α-bromomethylstyrene as a chain transfer agent (WO 88 / 04304), a method of chemically bonding a polymerizable group (JP Patent Publication No. 60-133007), and a method using thermal decomposition (JP Patent Publication No. 11-240854). Among these, the method using a cobalt chain transfer agent is preferred in terms of the number of production steps being small and the use of a catalyst with a high chain transfer constant.

[0034] The weight average molecular weight (Mw) of compound a measured by gel permeation chromatography (GPC) is preferably from 1000 to 100000, more preferably from 1500 to 70000, even more preferably from 2000 to 50000, and most preferably from 3000 to 20000. The weight average molecular weight of compound a is preferably higher from the viewpoint of improving the retention when used as a composition containing compound a, and is preferably lower from the viewpoint of production stability.

[0035] [Adhesive] The pressure-sensitive adhesive comprises a composition containing a compound a and a polymer A. In the composition, the ratio of compound a to polymer A is preferably in the range of 0.1:99.9 to 30:70, more preferably 0.5:99.5 to 20:80, and more preferably 1:99 to 15:85, in terms of balancing the performance. When the content ratio of compound a is higher than the above lower limit, the holding power of the composition is improved. When the content ratio of compound a is lower than the above upper limit, the compatibility with other components contained in the composition is improved.

[0036] The pressure-sensitive adhesive may further contain other components, such as a solvent, a filler, a crosslinking agent, a tackifier resin, an antioxidant, a light stabilizer, a metal deactivator, an anti-aging agent, a moisture absorbent, a rust inhibitor, a hydrolysis inhibitor, and a reaction catalyst. Examples of the antioxidant include phenol-based, phosphorus-based, hydroxylamine-based, and sulfur-based antioxidants.

[0037] The adhesive may be a liquid adhesive containing a solvent, or a hot-melt type adhesive containing no solvent.

[0038] The adhesive can be used as an adhesive cured by active energy rays as necessary. As the active energy rays, ultraviolet rays are preferable from the viewpoint of versatility. Examples of the light source of ultraviolet rays include a xenon lamp, a high-pressure mercury lamp, and a metal halide lamp.

[0039] [Adhesive sheet] The pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer formed using a pressure-sensitive adhesive. The pressure-sensitive adhesive sheet may be a sheet consisting of only a pressure-sensitive adhesive layer formed into a sheet shape, or may be a sheet formed of a pressure-sensitive adhesive layer formed into a sheet shape with a release substrate laminated on one or both sides thereof.

[0040] The adhesive layer may be made of an adhesive or a cured product of the adhesive. From the viewpoint of handling of the adhesive sheet, it is preferable that the adhesive layer is made of an adhesive cured by ultraviolet light. The thickness of the adhesive layer can be appropriately set depending on the application, and is preferably 10 to 500 μm, and more preferably 20 to 100 μm. The materials to be bonded using the adhesive are not particularly limited, but can be used, for example, for bonding window films for vehicles, buildings, etc., bonding labels for labeling, bonding various panels such as liquid crystal panels, bonding transparent plate materials such as glass, etc. EXAMPLES

[0041] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. In the following, "parts" means "parts by mass." Evaluations were performed by the following methods.

[0042] <Molecular weight of compound a> Measurement was performed using a gel permeation chromatography (GPC) device (HLC-8320, manufactured by Tosoh Corporation). A 0.2% by mass solution of the compound in tetrahydrofuran (THF) was prepared, and 10 mL of the solution was injected into the device equipped with a Tosoh Corporation column (TSKgel SuperHZM-M×HZM-M×HZ2000, TSKguardcolumn SuperHZ-L), and measurement was performed under the following conditions: flow rate: 0.35 mL / min, eluent: THF (stabilizer: butylhydroxytoluene (BHT)), column temperature: 40°C. The number average molecular weight (Mn) and weight average molecular weight (Mw) were calculated in terms of polystyrene.

[0043] <Molecular weight of polymer A> Measurement was performed using a GPC device (HLC-8120, manufactured by Tosoh Corporation). A 0.3% by mass THF solution of the polymer was prepared, and 20 mL of the solution was injected into the above device equipped with a Tosoh Corporation column (TSKgel SuperHM-H x 4, TSKguardcolumn SuperH-H), and measurement was performed under the following conditions: flow rate: 0.6 mL / min, eluent: THF (stabilizer BHT), column temperature: 40°C. The number average molecular weight (Mn) and weight average molecular weight (Mw) were calculated in terms of polystyrene.

[0044] <Tgについて> The glass transition temperature (Tg) is a value calculated by the following formula, converted from absolute temperature (K) to Celsius (° C.). 1 / Tg=Σ(wi / Tgi) In the above formula, wi represents the mass fraction of monomer i constituting the polymer, and Tgi represents the glass transition temperature of a homopolymer of monomer i constituting the polymer. In the above formula, Tg and Tgi are values ​​expressed in absolute temperature (K). The glass transition temperature of the homopolymer of monomer I is calculated according to Polymer Handbook (J. Brandrup, Interscience, 1989). The value is listed in.

[0045] <Preparation of test specimen> After diluting polymer A with ethyl acetate so that the composition had a solid content of 33.3%, compound a was added and mixed, and it was visually confirmed that no compound a remained dissolved, resulting in a pressure-sensitive adhesive composition that was liquid at room temperature (23°C). The pressure-sensitive adhesive composition was applied onto a PET film having a thickness of 38 μm using an applicator, and dried at 90° C. for 1 hour to form a pressure-sensitive adhesive layer. The PET film (PET) on which the adhesive layer was formed was irradiated with ultraviolet light in the air using a high-pressure mercury lamp to harden the adhesive layer. The irradiation energy was 35 mJ / cm. 2(Actual value measured using an integrating light meter UV POWER PUCK II (S / N 13685) (manufactured by EIT, USA).) A release-treated PET film (release PET) was placed on the upper surface of the film to obtain a laminate having a release PET-adhesive layer-PET structure. The thickness of the adhesive layer was 50 μm. The cured laminate was cut into a rectangular shape having a width of 25 mm and a length of 250 mm to prepare a test piece. <Appearance of test piece> The appearance of the test piece was visually observed to confirm the presence or absence of cloudiness.

[0046] <Melt viscosity> The adhesive composition was applied with an applicator, and the adhesive layer was dried at 90°C for 1 hour, and then measured using a HAAKE MARS viscoelasticity measuring device. The viscosity (η*) value measured at 130°C and a frequency of 0.02 Hz using a cone plate with a diameter of 35 mm was taken as the melt viscosity value at 130°C. <Coatability> The coatability was evaluated based on the melt viscosity measured by the above method according to the following criteria. A: Melt viscosity is ≦100 Pa·s. B: Melt viscosity >100 Pa·s.

[0047] <Adhesive strength> The release PET was peeled off from the test piece to expose the adhesive layer, and the test piece was attached to a 30 mm x 110 mm stainless steel (SUS) plate using a 3 kg hand roller so that the bonding surface was 25 mm x 70 mm. The peel strength (N / 25 mm) against the SUS plate was measured at a peel angle of 180° and a tensile speed of 300 mm / min, and this was taken as the adhesive strength.

[0048] <Holding power> At one end of the test piece, the release PET was peeled off to expose the adhesive layer, and the test piece was horizontally attached to a 30 mm x 110 mm SUS plate using a 3 kg hand roller so that the bonding surface was 25 x 25 mm. The test piece was left for 15 minutes in a constant temperature and humidity tester at a temperature of 80°C and a humidity of 45% or 85%. Immediately after that, a SUS plate was placed so that a force was applied to the bonding surface in the shear direction, and a load of 1.2 kg was applied with the other end of the test piece facing down. The holding time was measured and recorded as the holding force.

[0049] <Production Example 1 [Dispersant 1]> In a polymerization apparatus equipped with a stirrer, a cooling tube, a thermometer, and a nitrogen gas inlet tube, 900 parts of deionized water, 60 parts of 2-sulfoethyl sodium methacrylate, 10 parts of potassium methacrylate, and 12 parts of methyl methacrylate (MMA) were placed and stirred, and the temperature was raised to 50°C while replacing the inside of the polymerization apparatus with nitrogen. Furthermore, 0.08 parts of 2,2'-azobis(2-methylpropionamidine) dihydrochloride were added as a polymerization initiator, and the temperature was raised to 60°C. After the temperature was raised, MMA was continuously dropped at a rate of 0.24 parts / min for 75 minutes using a dropping pump. The mixture was kept at 60°C for 6 hours, and then cooled to room temperature to obtain a dispersant 1 with a solid content of 10% by mass.

[0050] <Production Example 2 [Chain Transfer Agent 1]> In a synthesis apparatus equipped with a stirrer, 1.00 g of cobalt(II) acetate tetrahydrate, 1.93 g of diphenylglyoxime, and 80 mL of diethyl ether previously deoxygenated by nitrogen bubbling were added under a nitrogen atmosphere and stirred at room temperature for 30 minutes. Furthermore, 10 mL of boron trifluoride diethyl ether complex was added and stirred for 6 hours. The mixture was filtered, the solid was washed with diethyl ether, and vacuum dried for 15 hours to obtain 2.12 g of chain transfer agent 1, which is a reddish brown solid.

[0051] <Production example 3 [compound a-1]> In a polymerization apparatus equipped with a stirrer, a cooling tube, a thermometer, and a nitrogen gas inlet tube, 145 parts of deionized water, 0.1 parts of sodium sulfate, and 0.25 parts of dispersant 1 (solid content 10% by mass) were placed and stirred to obtain a uniform aqueous solution. Further, 100 parts of MMA, 0.0022 parts of chain transfer agent 1, and 0.4 parts of Perocta (registered trademark) O (1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, manufactured by NOF Corporation) as a polymerization initiator were added to obtain an aqueous suspension. The inside of the polymerization apparatus was then replaced with nitrogen, the temperature was raised to 80°C and the mixture was stirred for 3.5 hours, and in order to further increase the polymerization rate, the temperature was raised to 90°C and maintained for 1 hour. The mixture was then cooled to 40°C to obtain an aqueous suspension containing the compound. The aqueous suspension obtained was filtered through a filter, and the residue remaining on the filter was washed with deionized water, dehydrated, and dried at 40°C for 16 hours to obtain compound a-1. The molecular weight measurement results are shown in Table 1.

[0052] <Production Examples 4-5 [Compounds a-2-a-3]> Compounds a-2 to a-3 were produced in the same manner as in Production Example 3, except that the formulation was changed as shown in Table 1. The units of the formulations shown in Table 1 are parts by mass.

[0053] [Table 1]

[0054] The symbols in each table are as follows: MMA: Methyl methacrylate EHMA: 2-Ethylhexyl methacrylate SLMA: Alkyl methacrylate (Acryester SL, manufactured by Mitsubishi Chemical Corporation)

[0055] <Production Example 6 [(Meth)acrylic copolymer A-1]> A four-neck flask equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen gas inlet was charged with 40 parts of ethyl acetate and 7.7 parts of isopropyl alcohol (IPA), and the external temperature was raised to 85°C under nitrogen gas aeration. After the external temperature reached 85°C and the internal temperature stabilized, a mixture consisting of 25 parts of ethyl acetate, 89.7 parts of n-butyl acrylate (n-BA), 5 parts of acrylic acid (AA), 5 parts of compound A-1, 0.3 parts of 4-MBP, and 0.13 parts of Niper (registered trademark) BMT-K40 (manufactured by NOF Corp., trade name) was added dropwise over 4 hours. After holding for 1 hour after the end of the dropwise addition, a mixture consisting of 0.5 parts of Perocta O and 10 parts of ethyl acetate was added over 30 minutes. After that, after keeping for 2 hours, 0.5 parts of an antioxidant (manufactured by BASF, product name "Irganox (registered trademark) 1010") was added, and ethyl acetate was added so that the solid content (the ratio of the monomer charge in (monomer + solvent charge)) became 53 mass%, and then the mixture was cooled to room temperature to obtain a copolymer solution A-1 containing a (meth)acrylic copolymer A-1.

[0056] <Production Example 7 [(Meth)acrylic copolymer A-2]> A four-neck flask equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen gas inlet was charged with 40 parts of ethyl acetate, 9.7 parts of isopropyl alcohol (IPA), and 5 parts of compound A-1, and the external temperature was raised to 85°C under nitrogen gas aeration. After the external temperature reached 85°C and the internal temperature stabilized, a mixture consisting of 25 parts of ethyl acetate, 89.7 parts of n-butyl acrylate (n-BA), 5 parts of acrylic acid (AA), 0.3 parts of 4-MBP, and 0.13 parts of Niper (registered trademark) BMT-K40 (manufactured by NOF Corp., trade name) was added dropwise over 4 hours. After holding for 1 hour after the end of the dropwise addition, a mixture consisting of 0.5 parts of Perocta O and 10 parts of ethyl acetate was added over 30 minutes. After that, after keeping for 2 hours, 0.5 parts of an antioxidant (manufactured by BASF, product name "Irganox (registered trademark) 1010") was added, and ethyl acetate was added so that the solid content (the ratio of the monomer charge in (monomer + solvent charge)) became 53 mass%, and then the mixture was cooled to room temperature to obtain a copolymer solution A-2 containing a (meth)acrylic copolymer A-2.

[0057] The compositions and properties of the (meth)acrylic copolymers A-1 and A-2 obtained in Production Examples 6 and 7 are shown in Table 2.

[0058] [Table 2]

[0059] The symbols in each table are as follows: IPA: Isopropyl alcohol n-BA: n-butyl acrylate AA: Acrylic acid 4-MBP: 4-methacryloyloxybenzophenone

[0060] <Examples 1 to 6 and Comparative Examples 1 to 3> Test pieces were prepared by the above method using the polymer compositions obtained by blending the polymers and compounds as shown in Table 3, and the appearance, adhesive strength, holding strength, and resistance to substrate contamination of the test pieces were evaluated. The evaluation results are shown in Table 3.

[0061] [Table 3]

[0062] It was confirmed that the polymer compositions of Examples 1 to 6 were superior to the polymer compositions of Comparative Examples 1 to 3 in terms of appearance, adhesive strength, and holding strength. Comparative Examples 1 and 2 did not contain the compound of the present invention, and therefore the adhesive strength and holding power were insufficient. In Comparative Example 3, a compound made of a single MMA composition was blended, and therefore the compatibility with the polymer composition was insufficient, causing the product to become cloudy and resulting in poor appearance. In addition, the melt viscosity at 130°C before UV irradiation was high, and it was found that there was a problem with the coatability.

Claims

1. A composition comprising: a polymer A containing a structural unit derived from a monomer M capable of forming a new bond upon photoexcitation; and a compound a containing two or more structural units derived from a monomer m represented by formula (1) and having a radical polymerizable group at an end thereof, The monomer M has a structure of formula (2), The weight average molecular weight of the polymer A is 5,000 to 2,000,000, The weight average molecular weight of the compound a is 1,000 to 100,000; A composition in which the ratio of the compound a to the polymer A is 0.1:99.9 to 30:

70. 【Chemistry 1】 (In the formula, X represents a hydrogen atom or a methyl group, and Y represents an unsubstituted or substituted alkyl group having 2 to 16 carbon atoms, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, an unsubstituted or substituted organosilyl group, or an unsubstituted or substituted (poly)organosiloxane group. The substituents in these groups are each at least one selected from the group consisting of alkyl groups, aryl groups, heteroaryl groups, non-aromatic heterocyclic groups, aralkyl groups, alkaryl groups, carboxylic acid groups, carboxylate groups, epoxy groups, hydroxy groups, alkoxy groups, primary amino groups, secondary amino groups, tertiary amino groups, isocyanato groups, sulfonic acid groups, and halogen atoms.) 【Chemistry 2】 (In the formula, R A and R B each independently represent an alkyl group, a carboxy group, or a halogen atom, n represents an integer of 0 to 5, m represents an integer of 0 to 4, and X represents a (meth)acryloyloxy group or a (meth)acryloyloxyalkyleneoxy group.)

2. The composition of claim 1 , wherein the new bonds are cross-linked structures.

3. The composition according to claim 2 , wherein the monomer M generates an active species upon photoexcitation to form the crosslinked structure.

4. The composition according to claim 3 , wherein the active species is a radical.

5. The composition according to any one of claims 1 to 4, wherein the compound a has a glass transition temperature of -100°C or higher and 100°C or lower.

6. The composition according to any one of claims 1 to 5, wherein the content of the structural unit derived from the monomer M is 0.01% by mass or more and 50% by mass or less, relative to 100% by mass of the total mass of the composition.

7. The composition according to any one of claims 1 to 6, wherein the polymer A has a glass transition temperature of 0°C or lower.

8. The composition according to any one of claims 1 to 7, wherein the compound a has a structure represented by formula (3): 【Chemistry 3】 (In the formula, R is a group having a structure that generates an active species upon photoexcitation, or a linear or branched alkyl group having 1 to 30 carbon atoms, Z is a terminal group, and R ２１ represents a hydrogen atom or a methyl group, R ２２ represents an unsubstituted or substituted alkyl group, an unsubstituted or substituted alicyclic group, an unsubstituted or substituted aryl group, an unsubstituted or substituted heteroaryl group, an unsubstituted or substituted aralkyl group, an unsubstituted or substituted alkaryl group, an unsubstituted or substituted organosilyl group, or an unsubstituted or substituted (poly)organosiloxane group, each of which is at least one selected from the group consisting of an alkyl group, an aryl group, a heteroaryl group, a non-aromatic heterocyclic group, an aralkyl group, an alkaryl group, a carboxylic acid group, a carboxylate group, an epoxy group, a hydroxy group, an alkoxy group, a primary amino group, a secondary amino group, a tertiary amino group, an isocyanato group, a sulfonic acid group, and a halogen atom, and n represents a natural number of 2 or more. The terminal group in Z is a hydrogen atom or a group derived from a radical polymerization initiator.

9. The composition according to any one of claims 1 to 8, wherein the polymer A comprises a (meth)acrylic copolymer.

10. A pressure-sensitive adhesive obtained by irradiating the composition according to any one of claims 1 to 9 with ultraviolet light.

11. A pressure-sensitive adhesive comprising the composition according to any one of claims 1 to 9.

12. A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive according to claim 10 or 11.

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