JP5999999B2 - Adhesive, adhesive for electronic device, electronic device using the same, and adhesive composition - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive, a pressure-sensitive adhesive for electronic devices, an electronic device, and a pressure-sensitive adhesive composition. More specifically, the pressure-sensitive adhesive that exhibits low volume resistivity and excellent transparency, and a pressure-sensitive adhesive composition for obtaining the same In addition, the present invention relates to an electronic device pressure-sensitive adhesive and an electronic device.

In recent years, a touch panel type has attracted attention as a trend of image display methods, and in particular, a capacitive type touch panel has become widespread. In such a capacitive touch panel, an adhesive layer (a layer made of an adhesive) is used as an insulating layer in addition to the purpose of attaching the transparent member.
Capacitive touch panels are designed to sense when the touch panel is touched with a finger or the like, and the output signal at that position changes, and the amount of change in the signal exceeds a certain threshold. If the electrical resistance of the material between them is high, malfunction and reaction may be delayed.
However, in a capacitive touch panel using a conventional pressure-sensitive adhesive layer, a malfunction that may be caused by the pressure-sensitive adhesive layer may occur, and in particular, a signal change from the outside cannot be read with high sensitivity. In some cases, malfunctions may occur.
Moreover, not only the touch panel but also a capacitance detection type device such as a twisting ball type electronic paper may cause a malfunction as described above or a reaction speed may be slow.

  Therefore, even if it is used for bonding members in capacitive sensing devices such as capacitive touch panels and electronic paper, adhesives for electronic devices can prevent signal malfunctions and delays. Research has been conducted in search of

  For example, Patent Document 1 is formed from (meth) acrylic acid alkyl ester, (meth) acrylic acid alkoxy ester, and polar group-containing monomer having a linear or branched alkyl group having 1 to 14 carbon atoms. An adhesive sheet having an adhesive layer made of an acrylic polymer is described.

WO2007 / 147047

  However, although the technique disclosed in Patent Document 1 shows a certain low volume resistivity, it has not been sufficient to clear the demand for electrical characteristics at a higher level in recent years using such a technique. .

  In view of the above, the present invention has an object of providing a pressure-sensitive adhesive exhibiting a low volume resistivity and excellent transparency.

  However, as a result of intensive studies in view of such circumstances, the present inventor has found that an acrylic resin having a higher hydroxyl group content than conventional ones in an adhesive composition comprising an adhesive resin composed of an acrylic resin and a monofunctional monomer. Furthermore, by using a pressure-sensitive adhesive composition in which a specific ethylenically unsaturated monomer having a high polarizability is used in a relatively larger amount than a conventionally used monofunctional monomer, the resulting pressure-sensitive adhesive has a low volume. Since it shows resistivity and is excellent in transparency, it has been found that it is particularly effective as an adhesive for electronic devices, and the present invention has been completed.

That is, the gist of the present invention is that an adhesive composition [I] containing an acrylic resin (A) and an ethylenically unsaturated monomer (B) containing one ethylenically unsaturated group is an active energy ray. And / or an adhesive that is cured by heat, wherein the acrylic resin (A) is an acrylic resin obtained by polymerizing a monomer component containing 15 to 50% by weight of a hydroxyl group-containing monomer, and ethylene. The ethylenically unsaturated monomer (B) containing one ethylenically unsaturated group has an aromatic ring or an alicyclic ring substituted with two or more substituents, and the ethylenically unsaturated monomer (B content) is an acrylic resin (a) 50 to 300 parts by weight der per 100 parts by weight is, the ethylenically unsaturated monomer having two or more aromatic rings or alicyclic substituted with a substituent (B) is 2- (meta) Acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropyl hexahydrohydrogen phthalate, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl-2-hydroxyethyl-phthalate Acid, 2- (meth) acryloyloxyethyl 2-hydroxypropyl phthalate, 2- (meth) acryloyloxypropyl hydrogen phthalate, 2- (meth) acryloyloxypropyl tetrahydrohydrogen phthalate, o-phenylphenol EO modified (meth) acrylate, EO-modified cresol (meth) acrylate, EO-modified nonylphenol (meth) acrylate, tribromophenyl (meth) acrylate, EO-modified tribromophenyl (meth) acrylate, isobornyl (meth) acrylate Over preparative relates adhesives to 3,3,5-trimethylcyclohexane (meth) acrylate or 1,4-cyclohexanedimethanol mono (meth) acrylate der wherein Rukoto.
Furthermore, it is related with the adhesive for electronic devices, the electronic device using the adhesive for electronic devices, and an adhesive composition.

  The pressure-sensitive adhesive of the present invention can exhibit a low volume resistivity and is also excellent in transparency. In particular, it is an electronic device such as a capacitive touch panel, a capacitance detection type device, or a component for electronic paper. This is effective for applications such as bonding the members constituting the device.

The present invention will be described in detail below, but these show examples of desirable embodiments.
In the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate.

First, the pressure-sensitive adhesive composition [I] of the present invention will be described.
The pressure-sensitive adhesive composition [I] of the present invention comprises an acrylic resin (A) and an aromatic compound (B) containing one ethylenically unsaturated group.

  The acrylic resin (A) used in the present invention contains 15 to 50% by weight of the hydroxyl group-containing monomer (a1) as an essential component, and a (meth) acrylic acid alkyl ester monomer (a2). It can be obtained by polymerizing a monomer component containing the group-containing copolymerizable monomer (a3) and other polymerizable monomers (a4).

Examples of the hydroxyl group-containing monomer (a1) include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8- Caprolactone-modified monomers such as (meth) acrylic acid hydroxyalkyl esters having 1 to 16 (preferably 1 to 12) carbon atoms of alkyl groups such as hydroxyoctyl (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth) acrylate, diethylene glycol (meth) acrylate, polyoxyalkylene-modified monomers such as polyethylene glycol (meth) acrylate, other 2-acryloyloxyethyl - primary hydroxyl group-containing monomers such as 2-hydroxyethyl phthalate, 2 Secondary hydroxyl group-containing monomers such as hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-chloro 2-hydroxypropyl (meth) acrylate; 2,2-dimethyl 2-hydroxyethyl (meth) acrylate, etc. And a tertiary hydroxyl group-containing monomer.

  As the hydroxyl group-containing monomer (a1) used in the present invention, it is also preferable to use a monomer having a content of di (meth) acrylate as an impurity of 0.5% or less, more preferably 0.2% or less. It is preferable to use 0.1% or less, and specifically, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are preferable.

The content of the hydroxyl group-containing monomer (a1) in all monomer components is required to be 15 to 50% by weight, preferably 20 to 45% by weight, particularly preferably 30 to 40% by weight. is there.
If the content of the hydroxyl group-containing monomer (a1) is too small, the compatibility with the ethylenically unsaturated monomer (B) containing one ethylenically unsaturated group described later may be reduced, or the volume resistivity may be increased. If the amount is too large, the diester compound contained in the hydroxyl group-containing monomer is contained in a large amount, so that gelation easily occurs during the polymerization reaction.

  As such a (meth) acrylic acid alkyl ester monomer (a2), the alkyl group usually has 1 to 20, particularly 1 to 12, more preferably 1 to 8, particularly 4 to 8 carbon atoms. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-propyl (meth) acrylate , N-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (Meth) acrylate, isobornyl (meth) ac Rate, and the like. These can be used alone or in combination of two or more.

  Among these (meth) acrylic acid alkyl ester monomers (a2), n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferred in terms of polymerizability, adhesive properties, ease of handling, and availability of raw materials. N-butyl (meth) acrylate is preferably used because it is excellent in durability.

  The content of the (meth) acrylic acid alkyl ester monomer (a2) in all monomer components is preferably 50 to 85% by weight, particularly preferably 55 to 80% by weight, and more preferably 60 to 75% by weight. If the content of the (meth) acrylic acid alkyl ester monomer (a2) is too small, the adhesive strength when used as an adhesive tends to be insufficient, and if too large, the content of (a1) is relatively low. Since the content decreases, the effects of the present invention tend not to be obtained.

  Examples of the functional group-containing copolymerizable monomer (a3) (excluding (a1)) include functional groups such as oxyalkylene group-containing monomers, amide group-containing monomers, amino group-containing monomers, nitrogen-containing monomers, and glycidyl group-containing monomers. Examples thereof include a copolymerizable monomer, and one or more selected from these are used.

  Examples of the oxyalkylene group-containing monomer include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-butoxyethyl (meth) acrylate, and 2-butoxydiethylene glycol. (Meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, octoxypolyethylene glycol- Polypropylene glycol mono (meth) acrylate, Lauroxy polyethylene glycol mono (meth) acrylate, stearo Aliphatic (meth) acrylic acid esters such as xylethylene glycol mono (meth) acrylate, 2-phenoxyethyl (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, phenoxy polyethylene glycol-polypropylene glycol (meth) acrylate, Examples thereof include aromatic (meth) acrylic acid esters such as nonylphenol ethylene oxide adduct (meth) acrylate.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, N- (n-butoxyalkyl) acrylamide, N- (n-butoxyalkyl) methacrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl. (Meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, acrylamide-3-methylbutylmethylamine, dimethylaminoalkylacrylamide, dimethylaminoalkylmethacrylamide and the like.

  Examples of the amino group-containing monomer include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and quaternized products thereof.

  Examples of the nitrogen-containing monomer include acryloylmorpholine.

  Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

  The content ratio of the functional group-containing copolymerizable monomer (a3) in all monomer components is preferably 0 to 15% by weight, particularly preferably 0.1 to 10% by weight, and more preferably 0.1 to 5% by weight. When the functional group-containing copolymerizable monomer (a3) is too small, the adhesive performance tends to be lowered, and when it is too much, the storage stability tends to be lowered.

  Examples of other polymerizable monomers (a4) include acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, vinyl pyridine, vinyl pyrrolidone, itaconic acid. Examples thereof include monomers such as dialkyl esters, dialkyl esters of fumaric acid, allyl alcohol, acrylic chloride, methyl vinyl ketone, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, and dimethylallylvinylketone.

  Further, as other polymerizable monomer (a4), phenyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, ethoxylated o-phenylphenyl (meth) may be used as long as the effects of the present invention are not impaired. ) Aromatic ring-containing monomers such as acrylate, phenyldiethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, and styrene may be used.

  The content ratio of the other copolymerizable monomer (a4) in all monomer components is preferably 0 to 20% by weight, particularly preferably 0.1 to 15% by weight, and more preferably 0.1 to 10% by weight. If the content of the other copolymerizable monomer (a4) is too large, the adhesive performance tends to be lowered.

  For the purpose of increasing the molecular weight, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate A compound having two or more ethylenically unsaturated groups such as divinylbenzene can also be used in combination.

  The acrylic resin (A) is produced by polymerizing the monomer components (a1) to (a4). In such polymerization, solution radical polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc. It can carry out by the conventionally well-known method. Among these, it is preferable to prepare by solution radical polymerization since the molecular weight can be easily controlled, an emulsifier may not be used, and other components than the polymer component can be easily removed by drying. For example, in an organic solvent, a hydroxyl group-containing monomer (a1), a (meth) acrylic acid alkyl ester monomer (a2), a functional group-containing copolymerizable monomer (a3), other polymerizable monomers (a4), a polymerization initiator Are mixed or added dropwise and polymerized at reflux or at 50 to 90 ° C. for 2 to 20 hours.

  Examples of the organic solvent used for the polymerization include aromatic hydrocarbons such as toluene and xylene, esters such as methyl acetate, ethyl acetate and butyl acetate, aliphatic alcohols such as n-propyl alcohol and isopropyl alcohol, acetone, Examples include ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

  As the polymerization initiator used for such radical polymerization, azo-based polymerization initiators such as azobisisobutyronitrile and azobisdimethylvaleronitrile, which are usual radical polymerization initiators, benzoyl peroxide, lauroyl peroxide, di- Specific examples thereof include peroxide polymerization initiators such as t-butyl peroxide and cumene hydroperoxide.

  About the weight average molecular weight of acrylic resin (A), it is 200,000-3 million normally, Preferably it is 400,000-2 million, Most preferably, it is 800,000-150. When the weight average molecular weight is too small, the durability performance tends to be lowered. When the weight average molecular weight is too large, a large amount of a diluent solvent is required, which tends to be undesirable in terms of coating property and cost.

  The degree of dispersion (weight average molecular weight / number average molecular weight) of the acrylic resin (A) is preferably 20 or less, particularly preferably 10 or less, and further preferably 6 or less. When the degree of dispersion is too high, the durability performance of the pressure-sensitive adhesive layer is lowered, and there is a tendency that a crack or peeling occurs easily. The lower limit of the degree of dispersion is usually 2 from the viewpoint of production limit.

  Furthermore, the glass transition temperature of the acrylic resin (A) is preferably −100 to 0 ° C., particularly preferably −80 to −10 ° C., more preferably −70 to −20 ° C. If the glass transition temperature is too high. There is a tendency that tackiness is lowered and workability such as pasting tends to be lowered, and when it is too low, processing suitability such as paste sticking tends to be lowered.

Ｔg：共重合体のガラス転移温度（Ｋ）
Ｔga：モノマーＡのホモポリマーのガラス転移温度（Ｋ） Ｗa：モノマーＡの重量分率
Ｔgb：モノマーＢのホモポリマーのガラス転移温度（Ｋ） Ｗb：モノマーＢの重量分率
Ｔgn：モノマーＮのホモポリマーのガラス転移温度（Ｋ） Ｗn：モノマーＮの重量分率
（Ｗa＋Ｗb＋・・・＋Ｗn＝１） In addition, said weight average molecular weight is a weight average molecular weight by standard polystyrene molecular weight conversion, and it is a column in high performance liquid chromatography (The Japan Waters company "Waters 2695 (main body)" and "Waters 2414 (detector)"). : Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / piece, filler material: styrene-divinylbenzene copolymer, filler The particle diameter is measured by using three series of 10 μm), and the same method can be used for the number average molecular weight. The degree of dispersion is determined from the weight average molecular weight and the number average molecular weight. The glass transition temperature is calculated from the following Fox equation.

Tg: Glass transition temperature of copolymer (K)
Tga: Glass transition temperature of monomer A homopolymer (K) Wa: Weight fraction of monomer A Tgb: Glass transition temperature of homopolymer of monomer B (K) Wb: Weight fraction of monomer B Tgn: Homogeneity of monomer N Glass transition temperature of polymer (K) Wn: weight fraction of monomer N (Wa + Wb +... + Wn = 1)

  The ethylenically unsaturated monomer (B) containing one ethylenically unsaturated group used in the present invention (hereinafter sometimes abbreviated as “monofunctional monomer (B)”) is composed of one ethylene in the molecule. It is necessary that the compound be a compound having an aromatic unsaturated group or an alicyclic ring substituted with two or more substituents.

  Examples of the functional group containing an ethylenically unsaturated group include a (meth) acryloyl group, a crotonoyl group, a vinyl group, and an allyl group. Among them, the (meth) acryloyl group is preferably an active energy ray and / or Or it is preferable at the point which reaction tends to advance when hardening by heat.

  Examples of the aromatic ring contained in the monofunctional monomer (B) include an aromatic hydrocarbon ring {for example, a benzene ring, a polycyclic aromatic hydrocarbon ring [for example, a condensed polycyclic aromatic hydrocarbon ring (for example, naphthalene). Ring, anthracene ring, phenanthrene ring, fluorene ring, pyrene ring, fluoranthene ring, triphenylene ring, naphthacene ring, perylene ring, benzo [a] pyrene ring, benzo [e] pyrene ring, etc. condensed 2- to 6-ring aromatic carbonization Hydrogen rings, etc.), aromatic hydrocarbon rings in which a plurality of aromatic hydrocarbon rings (which may be condensed polycyclic aromatic hydrocarbon rings) are directly bonded (for example, biphenyl ring, phenylnaphthalene ring, terphenyl ring) An aromatic hydrocarbon ring in which 2 to 6 C6-10 arene rings are directly bonded, and the like], etc.], a hetero atom (particularly a nitrogen atom, An aromatic ring containing at least one heteroatom selected from an oxygen atom and a sulfur atom) (eg, pyrrole ring, pyridine ring, furan ring, thiophene ring, azole ring (eg, diazole ring, oxazole ring, thiazole ring, etc.)) , Heteroatom-containing monocyclic aromatic rings such as pyrazine ring; condensed polycyclic aromatic heterocycles [for example, thieno [2,3-b] thiophene ring, indole ring, benzo [b] furan ring, 3,4- Rings such as ethylenedioxythiophene ring, benzo [b] thiophene ring, benzopyran ring, quinoline ring, carbazole ring, phenanthridine ring, acridine ring, xanthene ring, thianthrene ring, etc. Aggregate aromatic heterocycles (eg, 2-6 aromatic heterocycles such as bipyridyl ring, bifuryl ring, and terpyridine ring are directly Etc.], etc., among these, benzene is preferred because of its availability and compatibility with the acrylic resin (A). A ring is preferred.

  Examples of the alicyclic ring contained in the monofunctional monomer (B) include cycloalkanes such as cyclopropane, cyclobutane, cyclopentane and cyclohexane, monocyclic alicyclic rings such as cyclopropene, cyclobutene, cyclopentene and cyclohexene, cycloalkene, Bicyclic alicyclic rings such as bicycloundecane, norbornene, norbornadiene, tricyclic or higher polycyclic alicyclic rings, spiro alicyclic rings, and the like.

  As the substituent contained in the monofunctional monomer (B), a known general substituent may be used, but a hydroxyl group, carboxyl group, amide group, or imide group can provide a low volume resistivity adhesive. In view of corrosivity and availability of raw materials, a hydroxyl group is more preferable.

Specific examples of the monofunctional monomer (B) include 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropyl hexahydrohydrogen phthalate, and 2- (meth) acryloyloxyethyl phthalate. Acid, 2- (meth) acryloyloxyethyl-2-hydroxyethyl-phthalic acid, 2- (meth) acryloyloxyethyl 2-hydroxypropyl phthalate, 2- (meth) acryloyloxypropyl hydrogen phthalate, 2- (meth) Phthalic acid derivatives such as acryloyloxypropyltetrahydrophthalate, biphenyl skeleton-containing (meth) acrylates such as o-phenylphenol EO-modified (meth) acrylate, cresol derivatives such as EO-modified cresol (meth) acrylate, EO-modified nonylphenol (me ) Nonylphenol derivatives such as acrylate, halogenated aromatic (meth) acrylates such as tribromophenyl (meth) acrylate, EO-modified tribromophenyl (meth) acrylate, and isobornyl group-containing (meth) acrylates such as isobornyl (meth) acrylate Examples include cyclohexane derivatives such as 3,3,5 trimethylcyclohexane (meth) acrylate and 1,4-cyclohexanedimethanol mono (meth) acrylate. Among these, hydroxyl group, carboxyl group, amide group, imide group are included. It is preferable that the monomer is contained in terms of low volume resistivity , particularly preferably a phthalic acid derivative, and more preferably 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid.

The molecular weight of the monofunctional monomer (B) is preferably 200 or more, particularly preferably 230 to 3000, and further preferably 250 to 2000.
If the molecular weight is too large, the compatibility with the acrylic resin (A) tends to be reduced, and if it is too small, it tends to volatilize easily.

The content of the monofunctional monomer (B), per 100 parts by weight of the acrylic resin (A), the Ri 50-300 parts by weight der, preferably 50 to 250 parts by weight, particularly preferably 70 to 200 parts by weight Particularly preferred is 100 to 200 parts by weight.
If the content of the monofunctional monomer (B) is too large, the compatibility with the acrylic resin (A) tends to be reduced, or the pressure-sensitive adhesive layer tends to be too hard, and if it is too small, the volume resistivity increases. Tend.

  In the present invention, the pressure-sensitive adhesive composition [I] containing the acrylic resin (A) and the monofunctional monomer (B) as essential components contains active energy rays and / or heat (active energy ray irradiation and / or It is cured by heating to obtain a pressure-sensitive adhesive.

When performing the curing with the active energy ray and / or heat, the pressure-sensitive adhesive composition [I] further contains an ethylenically unsaturated monomer (C) (hereinafter referred to as “ It may be abbreviated as “polyfunctional monomer (C)”) in that the cohesive force of the entire pressure-sensitive adhesive layer can be adjusted, and the polymerization initiator (D) is preferably contained during irradiation with active energy rays. And / or it is preferable at the point which can stabilize reaction at the time of a heating.
In such curing, the monofunctional monomer (B) and the polyfunctional monomer (C) are polymerized (polymerized) by active energy rays and / or heat and cured.

  In the present invention, as a method of curing the pressure-sensitive adhesive composition [I], in addition to the component (A) and the component (B) (the component (C) or the component (D) as required) Further, there may be mentioned a method in which a crosslinking agent (E) described later is contained, and the pressure-sensitive adhesive composition [I] is cured with active energy rays and / or heat and cured with a crosslinking agent. In addition, when using a crosslinking agent (E), it is preferable that acrylic resin (A) has a functional group, and hardening (crosslinking) is performed by this functional group and a crosslinking agent reacting.

  In the present invention, the above-described curing by active energy rays and / or heat (irradiation of active energy rays and / or heating) is preferable in that it can be cured by irradiation of active energy rays such as ultraviolet rays for a very short time. However, it is also preferable to use curing (crosslinking) with a cross-linking agent in combination, and the cross-linking density of the pressure-sensitive adhesive is increased, the cohesive force is increased, and a further superior durability can be obtained.

  When the acrylic resin (A) is an unsaturated group-containing acrylic resin, the monofunctional monomer (B) (and polyfunctional monomer (C)) is polymerized by active energy rays and / or heat. Not only, but also curing accompanying polymerization of the unsaturated group-containing acrylic resin (A) and the monofunctional monomer (B) (and the polyfunctional monomer (C)) will occur.

  Examples of the polyfunctional monomer (C) include an ethylenically unsaturated monomer containing two or more ethylenically unsaturated groups in one molecule, such as a bifunctional monomer, a trifunctional or higher monomer, and urethane (meta ) Acrylate compounds, epoxy (meth) acrylate compounds, and polyester (meth) acrylate compounds can be used. Among these, it is preferable to use an ethylenically unsaturated monomer and a urethane (meth) acrylate-based compound from the viewpoint of excellent curing rate and ultimate physical properties.

  The bifunctional monomer may be any monomer containing two ethylenically unsaturated groups. For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene Glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene Oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, 1,6-hexanediol di (meth) acrylate 1,6-hexanediol ethylene oxide modified di (meth) acrylate, glycerin di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di ( (Meth) acrylate, diglycidyl phthalate di (meth) acrylate, hydroxypivalic acid-modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide-modified diacrylate, 2- (meth) acryloyloxyethyl acid phosphate diester It is done.

  The tri- or higher functional monomer may be any monomer containing three or more ethylenically unsaturated groups. For example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) ) Acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tri (meth) acryloyloxyethoxytrimethylolpropane, Glycerin polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate, ethylene oxide modified dipentaerythritol (Meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tetra (meth) acrylate, succinic acid modified pentaerythritol tri (meth) acrylate Etc.

  The urethane (meth) acrylate compound is a (meth) acrylate compound having a urethane bond in the molecule, a (meth) acrylic compound containing a hydroxyl group and a polyvalent isocyanate compound (if necessary, a polyol What is necessary is just to use what is obtained by making it react by a well-known general method, and what is necessary is just to use the thing of 300-4000 normally as the weight average molecular weight.

  The content of the polyfunctional monomer (C) is desirably 0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight, more preferably 100 parts by weight of the acrylic resin (A). 5 to 20 parts by weight. If the content of the polyfunctional monomer (C) is too large, tack tends to be lowered and workability such as bonding tends to be lowered, and if too small, the crosslinking density tends to be lowered and durability tends to be lowered.

  In the present invention, the monofunctional monomer (B) and the polyfunctional monomer can be used in that the crosslinking density is appropriate, the tackiness can be appropriately adjusted, and the durability can be balanced. The content ratio (mol%) of the monofunctional monomer (B) with respect to the total amount of the monomer (C) is preferably larger than 50 mol%, particularly preferably larger than 50 mol% and smaller than 100 mol%, more preferably 55 to 99 mol%. Particularly preferred is 60 to 98 mol%.

  If the content ratio of the monofunctional monomer (B) to the total amount of the monofunctional monomer (B) and the polyfunctional monomer (C) is too small, the content of the polyfunctional monomer (C) with respect to the monofunctional monomer (B) Therefore, the crosslink density tends to be too high and the tackiness tends to be lacking. In addition, when the content rate of the monofunctional monomer (B) with respect to the total amount of a monofunctional monomer (B) and a polyfunctional monomer (C) is too large, the polyfunctional monomer (C) with respect to a monofunctional monomer (B) Since the content decreases, the crosslinking density does not increase so much and the durability tends to be inferior.

  As the polymerization initiator (D), for example, various polymerization initiators such as a photopolymerization initiator (d1) and a thermal polymerization initiator (d2) can be used. It is preferable to use d1) in that it can be cured by irradiation with active energy rays such as ultraviolet rays for a very short time.

  Moreover, when using the said photoinitiator (d1), adhesive composition [I] is hardened by active energy ray irradiation, and when using a thermal polymerization initiator (d2), adhesive composition [ I] is cured, but it is also preferable to use both together if necessary.

  Examples of the photopolymerization initiator (d1) include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4- Acetophenones such as morpholinophenyl) butanone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl Ben such as ether Ins; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium Benzophenones such as chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy -3 Thioxanthones such as 4-dimethyl-9H-thioxanthone-9-one mesochloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl- And acyl phosphine oxides such as pentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; In addition, as for these photoinitiators (d1), only 1 type may be used independently and 2 or more types may be used together.

  These auxiliary agents include triethanolamine, triisopropanolamine, 4,4′-dimethylaminobenzophenone (Michler ketone), 4,4′-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, 4-dimethylaminobenzoic acid. Ethyl, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone Etc. can be used in combination.

  Among these, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone, 2-hydroxy-2-methyl-1- It is preferable to use phenylpropan-1-one.

  Examples of the thermal polymerization initiator (d2) include methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, acetyl acetate peroxide, 1,1-bis (t-hexyl peroxide). ) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1, 1-bis (t-butylperoxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy) -cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 1,1- Bis (t-butylperoxy) butane, 2,2-bis (4 -Di-t-butylperoxycyclohexyl) propane, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroper Oxide, t-butyl hydroperoxide, α, α′-bis (t-butylperoxy) diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-Butyl cumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne-3, isobutyryl peroxide, 3,5,5-trimethylhexa Noyl peroxide, octanoyl per Oxide, lauroyl peroxide, stearoyl peroxide, succinic acid peroxide, m-toluoyl benzoyl peroxide, benzoyl peroxide, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butyl) (Cyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethoxyhexyl peroxydicarbonate, di-3-methoxybutyl peroxydicarbonate, di-s-butyl peroxydicarbonate, Di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α'-bis (neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-te Lamethylbutyl peroxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxy Pivalate, t-butylperoxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylper) Oxy) hexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t- Hexyl peroxyisopropyl monocarbonate, t-butyl peroxyisobutyrate t-butyl peroxymalate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxylaurate, t-butyl peroxyisopropyl monocarbonate, t-butyl peroxy-2 -Ethylhexyl monocarbonate, t-butyl peroxyacetate, t-butyl peroxy-m-toluylbenzoate, t-butyl peroxybenzoate, bis (t-butylperoxy) isophthalate, 2,5-dimethyl-2,5 -Bis (m-toluylperoxy) hexane, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyallyl monocarbonate, t-butyltrimethylsilylper Oxide, 3,3 ', 4,4'-tetra Organic peroxide initiators such as (t-butylperoxycarbonyl) benzophenone and 2,3-dimethyl-2,3-diphenylbutane; 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 1- [(1-cyano-1-methylethyl) azo] formamide, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′- Azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis (2-methyl- N-phenylpropionamidine) dihydrochloride, 2,2'-azobis [N- (4-chlorophenyl) -2-methylpropionamidine] Hydride chloride, 2,2'-azobis [N- (4-hydrophenyl) -2-methylpropionamidine] dihydrochloride, 2,2'-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydrochloride 2,2'-azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride, 2,2'-azobis [N- (2-hydroxyethyl) -2-methylpropionamidine] dihydrochloride, 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) Lopan] dihydrochloride, 2,2'-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (5-hydroxy-3 , 4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane] dihydrochloride 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] ] Propionamide], 2,2'-azobis [2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide], 2,2'-azobis [2-me Til-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-methylpropionamide), 2,2'-azobis (2,4,4-trimethylpentane), 2,2'- Azobis (2-methylpropane), dimethyl-2,2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis [2- (hydroxymethyl ) Propionitrile] and the like; and the like. In addition, only 1 type may be used independently for these thermal polymerization initiators, and 2 or more types may be used together.

  About content of the said polymerization initiator (D), 0.01-10 weight part with respect to 100 weight part of said acrylic resin (A), Especially 0.1-7 weight part, Furthermore, 0.3 It is preferably ~ 3 parts by weight. If the content of the polymerization initiator (D) is too small, the curability tends to be poor and the physical properties tend to become unstable, and if it is too much, no further effect can be obtained. Moreover, it is preferable that a polymerization initiator (D) is 0.01-100 weight part with respect to a total of 100 weight part of a monofunctional monomer (B) and a polyfunctional monomer (C), More preferably, it is 0.00. 1 to 20 parts by weight, particularly preferably 1 to 12 parts by weight.

  Examples of the crosslinking agent (E) 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, an isocyanate-based crosslinking agent is preferably used from the viewpoint of improving the adhesion to the substrate and the reactivity with the base polymer.

  Examples of the isocyanate crosslinking agent include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and hexamethylene. Diisocyanate, diphenylmethane-4,4-diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, tetramethylxylylene diisocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, and polyisocyanate compounds thereof And adducts of a polyol compound such as trimethylolpropane, and burettes and isocyanurates of these polyisocyanate compounds.

  Examples of the epoxy crosslinking agent include bisphenol A / epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, and 1,6-hexanediol diglycidyl ether. , Trimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl erythritol, diglycerol polyglycidyl ether and the like.

  Examples of the aziridine-based crosslinking agent include tetramethylolmethane-tri-β-aziridinylpropionate, trimethylolpropane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4. '-Bis (1-aziridinecarboxamide), N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide) and the like can be mentioned.

  Examples of the melamine-based crosslinking agent include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexaptoxymethyl melamine, hexapentyloxymethyl melamine, hexahexyloxymethyl melamine, and melamine resin. .

  Examples of the aldehyde-based crosslinking agent include glyoxal, malondialdehyde, succindialdehyde, maleindialdehyde, glutardialdehyde, formaldehyde, acetaldehyde, benzaldehyde and the like.

  Examples of the amine-based crosslinking agent include hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetraamine, diethylenetriamine, triethyltetraamine, isophoronediamine, amino resin, polyamide, and the like.

  Examples of the metal chelate-based crosslinking agent include acetylacetone and acetoacetyl ester coordination compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, panadium, chromium, and zirconium. Can be mentioned.

  Moreover, these crosslinking agents (E) may be used independently and may use 2 or more types together.

  Usually, the content of the crosslinking agent (E) is preferably 0.01 to 10 parts by weight, more preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the acrylic resin (A). Particularly preferred is 0.1 to 2 parts by weight. If the amount of the crosslinking agent (E) is too small, there is a tendency that the cohesive force is insufficient and sufficient durability cannot be obtained. If the amount is too large, the flexibility and the adhesive strength are lowered, the durability is lowered, and peeling occurs. Since it is easy to occur, the use as an optical member, especially an optical member for electronic devices tends to be difficult.

Further, the pressure-sensitive adhesive composition [I] further includes a silane coupling agent, an antistatic agent, other acrylic pressure-sensitive adhesives, other pressure-sensitive adhesives, urethane resin, rosin, and rosin within a range not impairing the effects of the present invention. Esters, hydrogenated rosin esters, phenol resins, aromatic modified terpene resins, aliphatic petroleum resins, alicyclic petroleum resins, styrene resins, xylene resins, tackifiers, colorants, fillers, anti-aging Conventionally known additives such as an agent, an ultraviolet absorber, a functional dye, and the like, and a compound that causes coloration or discoloration upon irradiation with ultraviolet rays or radiation can be blended.
In addition to the above additives, a small amount of impurities contained in the raw materials for producing the constituent components of the pressure-sensitive adhesive composition [I] may be contained.

  Examples of the silane coupling agent include an epoxy group-containing silane coupling agent, a (meth) acryloyl group-containing silane coupling agent, a mercapto group-containing silane coupling agent, a hydroxyl group-containing silane coupling agent, and a carboxyl group-containing silane coupling. Agents, amino group-containing silane coupling agents, amide group-containing silane coupling agents, isocyanate group-containing silane coupling agents, and the like. These may be used alone or in combination of two or more. Among these, an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent are preferable in terms of improving adhesion to glass.

  Examples of the antistatic agent include cationic antistatic agents of quaternary ammonium salts such as imidazolium salts and tetraalkylammonium sulfonates, aliphatic sulfonates, higher alcohol sulfates, and higher alcohol alkylene oxide additions. Anion-type antistatic agents such as sulfuric acid ester salts, higher alcohol phosphate salts, higher alcohol alcohol alkylene oxide adduct phosphate salts, potassium bis (fluorosulfonyl) imide, lithium bis (trifluorosulfonyl) imide and lithium chloride And alkali metal salts such as alkaline earth metal salts, higher alcohol alkylene oxide adducts, and polyalkylene glycol fatty acid esters.

  Thus, in the present invention, a pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition [I] containing the acrylic resin (A) and the monofunctional monomer (B) as essential components is obtained.

  The pressure-sensitive adhesive of the present invention is preferably used as a pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive layer composed of the above pressure-sensitive adhesive composition [I] and a substrate.

  Next, a method for producing a pressure-sensitive adhesive sheet by applying and drying the pressure-sensitive adhesive composition [I] on a substrate and curing it by irradiation with active energy rays and / or heating will be described.

Examples of the substrate include polyester resins such as polyethylene naphthalate, polyethylene terephthalate, boribylene terephthalate, and polyethylene terephthalate / isophthalate copolymer; polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; polyvinyl fluoride, Polyfluorinated ethylene resins such as polyvinylidene fluoride and polyfluorinated ethylene; polyamides such as nylon 6 and nylon 6,6; polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl Alcohol copolymers, vinyl polymers such as polyvinyl alcohol and vinylon; cellulose resins such as cellulose triacetate and cellophane; polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate Acrylic resin such as polybutyl acrylate; polystyrene; polycarbonate; polyarylate; synthetic resin sheet such as polyimide, aluminum, copper, iron metal foil, paper such as fine paper, glassine paper, glass fiber, natural fiber, synthetic fiber And woven fabrics and non-woven fabrics, and those obtained by evaporating a metal such as ITO. These base materials can be used as a single layer body or a multilayer body in which two or more kinds are laminated.
In addition, when there is a possibility of deterioration due to solvent, etc., heat at the time of drying, irradiation of active energy rays, etc., first apply silicone etc. to a separator with releasability. It is preferable to bond to the base material.
Moreover, what is necessary is just to apply | coat to a separator and to bond with a separator, when making it a base material-less double-sided adhesive sheet. A preferred separator is a polyester-based resin, and particularly preferred is a polyethylene terephthalate treated with silicone.

  In applying the pressure-sensitive adhesive composition [I], the pressure-sensitive adhesive composition [I] is preferably diluted with a solvent, and the dilution concentration is preferably 5 to 90% by weight as a residual heating concentration. Particularly preferred is 10 to 60% by weight, and further 20 to 50% by weight. The solvent is not particularly limited as long as it can dissolve the pressure-sensitive adhesive composition [I]. Examples thereof include ester solvents such as methyl acetate, ethyl acetate, methyl acetoacetate, and ethyl acetoacetate, acetone Further, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, aromatic solvents such as toluene and xylene, and alcohol solvents such as methanol, ethanol and propyl alcohol can be used. Among these, ethyl acetate and methyl ethyl ketone are preferably used from the viewpoints of solubility, drying property, price, and the like.

  The pressure-sensitive adhesive composition [I] is applied by a conventional method such as roll coating, die coating, gravure coating, comma coating, or screen printing.

Further, the thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (film thickness after drying) is usually preferably 3 to 500 μm, particularly preferably 5 to 300 μm, and more preferably 10 to 250 μm. .

  For the above drying conditions, the drying temperature is usually 50 ° C to 250 ° C, preferably 60 ° C to 150 ° C, more preferably 65 ° C to 120 ° C, particularly preferably 70 ° C to 95 ° C, and the drying time is Usually 10 seconds to 10 minutes.

  Regarding the above curing conditions, when the pressure-sensitive adhesive composition [I] is cured by irradiation with active energy rays, as active energy rays, rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, X rays, γ rays, etc. In addition to electromagnetic waves, electron beams, proton beams, neutron beams, and the like can be used, but curing by ultraviolet irradiation is advantageous from the viewpoint of curing speed, availability of an irradiation device, price, and the like. In addition, when performing electron beam irradiation, it can harden | cure even without using the above-mentioned photoinitiator (d1).

As the light source for the ultraviolet irradiation, a high pressure mercury lamp, an electrodeless lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, or the like is used. In the case of the high-pressure mercury lamp, for example, it is performed under conditions of 5 to 3000 mJ / cm ² , preferably 10 to 1000 mJ / cm ² . Moreover, in the case of the said electrodeless lamp, it is performed on the conditions of 2-1500 mJ / cm < ² >, for example, Preferably 5-500 mJ / cm < ² >. The irradiation time varies depending on the type of the light source, the distance between the light source and the coating surface, the coating thickness, and other conditions, but it may be usually from several seconds to several tens of seconds, and in some cases, a fraction of a second.
On the other hand, in the case of the electron beam irradiation, for example, an electron beam having an energy in the range of 50 to 1000 Kev is used, and the irradiation amount is preferably 2 to 50 Mrad.

  Moreover, when using a thermal polymerization initiator (d2) at the time of hardening, a polymerization reaction is started and advanced by heating. The treatment temperature and treatment time at the time of curing by heating vary depending on the type of the thermal polymerization initiator (d2) to be used, and are usually calculated from the half-life of the initiator, but the treatment temperature is usually The temperature is preferably 70 ° C to 170 ° C, and the treatment time is usually preferably 0.2 to 20 minutes, and particularly preferably 0.5 to 10 minutes.

  In addition, when using a crosslinking agent (E), it is preferable to perform an aging process after manufacturing an adhesive sheet using the said method. Such aging treatment is performed to balance the physical properties of the adhesive. As aging conditions, the temperature is usually from room temperature to 70 ° C., and the time is usually from 1 day to 30 days. It may be performed under the conditions of 1 day to 20 days at ° C, preferably 3 to 10 days at 23 ° C, 1 to 7 days at 40 ° C.

  Moreover, in this invention, the optical member with an adhesive layer can also be obtained by carrying out lamination formation of the adhesive layer which consists of the said adhesive on an optical member (especially optical member for electronic devices).

Such optical members include transparent electrode films such as ITO conductive films such as ITO electrode films and polythiophenes, polarizing plates, retardation plates, elliptical polarizing plates, optical compensation films, brightness enhancement films, electromagnetic wave shielding films, and near-infrared absorbing films. And AR (anti-reflection) film. Among these, when it is a transparent electrode film, the effect of the present invention can be remarkably exhibited, and it is preferable in terms of low electric resistance and good sensitivity, and particularly preferably an ITO (indium tin oxide) electrode film.
Here, in the case where the pressure-sensitive adhesive composition containing the acrylic resin (A) and the monofunctional monomer (B) as essential components does not contain an acidic group, corrosion is particularly difficult to occur.

  The above-mentioned “does not contain an acidic group” specifically means that the acid value in the state where (A) and (B) are combined is preferably 10 mgKOH / g or less, particularly preferably 1 mgKOH / g. g or less, more preferably 0.1 mgKOH / g or less.

  In the optical member with the pressure-sensitive adhesive layer, it is preferable to further provide a release sheet on the surface opposite to the optical member surface of the pressure-sensitive adhesive layer. An adhesive layer and an adherend will be bonded. As such a release sheet, a silicon-based release sheet is preferably used.

  Regarding the method of curing / crosslinking the pressure-sensitive adhesive composition [I] when preparing the optical member with the pressure-sensitive adhesive layer to which the release sheet is bonded, [1] the pressure-sensitive adhesive composition [I] on the optical member ], The release sheet is pasted, and the treatment is performed by at least one of active energy ray irradiation and heating, [2] the pressure-sensitive adhesive composition [I] is applied on the release sheet, After drying, the optical member is bonded, and the treatment is performed by at least one of active energy ray irradiation and heating. [3] The adhesive composition [I] is applied and dried on the optical member, and the active energy ray is further applied. A method of pasting a release sheet after performing treatment by at least one of irradiation and heating, [4] coating and drying the adhesive composition [I] on the release sheet, and further irradiating with active energy rays and heating Less After also performs processing according to one, it can be to produce a method of bonding an optical member, a. Among these, the case of performing only the active energy ray irradiation by the method [2] is preferable from the viewpoint of not damaging the substrate, workability and stable production.

  About the drying conditions in the said drying process, drying temperature is 50 to 250 degreeC normally, Preferably it is 60 to 150 degreeC, More preferably, it is 65 to 120 degreeC, Most preferably, it is 70 to 95 degreeC. The time is usually 10 seconds to 10 minutes, but drying at a low temperature for a long time can volatilize and remove the organic solvent, and it can remain in the adhesive layer without volatilizing the monofunctional monomer. This is preferable. In consideration of economy and production efficiency, it is preferable that the drying time is short.

  In addition, when using a crosslinking agent (E) for adhesive composition [I], it is preferable to give an aging process after manufacturing the optical member with an adhesive layer using the said method. Such aging treatment is performed to balance the physical properties of the adhesive. As aging conditions, the temperature is usually from room temperature to 70 ° C., and the time is usually from 1 day to 30 days. It may be performed under the conditions of 1 day to 20 days at ° C, preferably 3 to 10 days at 23 ° C, 1 to 7 days at 40 ° C.

  The pressure-sensitive adhesive composition [I] is applied by a conventional method such as roll coating, die coating, gravure coating, comma coating, or screen printing.

  Up to here, after manufacturing the optical member with the pressure-sensitive adhesive layer once the release sheet is bonded, the pressure-sensitive adhesive that bonds the pressure-sensitive adhesive layer and the adherend (other optical members) after peeling off the release sheet. In the present invention, it is also preferable to produce a double-sided pressure-sensitive adhesive sheet using the above-mentioned pressure-sensitive adhesive composition [I], and a method of bonding optical members together using such a double-sided pressure-sensitive adhesive sheet. May be used.

  As such a double-sided pressure-sensitive adhesive sheet, a double-sided pressure-sensitive adhesive sheet having a known general configuration may be applied using the above acrylic pressure-sensitive adhesive, but in particular, it is excellent in transparency and has a high adhesive force with respect to the thickness to constitute. A double-sided pressure-sensitive adhesive sheet is preferred. Such a substrate-less double-sided pressure-sensitive adhesive sheet is formed by forming a pressure-sensitive adhesive layer made of the above acrylic pressure-sensitive adhesive on a release sheet, and then sticking another release sheet to the side of the pressure-sensitive adhesive layer that does not have a release sheet. It can be obtained by combining. As for the method of use, after peeling off one release sheet and bonding it to the adherend, the other release sheet may be peeled off and bonded to the adherend.

  About the gel fraction of the said adhesive sheet, the adhesive layer of an optical member with an adhesive layer, and the adhesive layer of a double-sided adhesive sheet, it is preferable that it is 30 to 98% from the point of durable performance and adhesive force, Especially. It is preferably 40 to 95%, particularly preferably 60 to 90%. If the gel fraction is too low, durability tends to be insufficient due to insufficient cohesive force. On the other hand, if the gel fraction is too high, the adhesive force tends to decrease due to an increase in cohesive force.

  In addition, in adjusting the gel fraction of an adhesive sheet, the adhesive for optical members, and a double-sided adhesive sheet to the said range, it is achieved by adjusting the kind and quantity of a crosslinking agent, etc., for example.

  The gel fraction is a measure of the degree of crosslinking (curing degree), and is calculated, for example, by the following method. That is, a pressure-sensitive adhesive sheet (not provided with a separator) in which a pressure-sensitive adhesive layer is formed on a polymer sheet (for example, polyethylene terephthalate film or the like) as a base material is wrapped with a 200-mesh SUS wire mesh, and 23 in toluene. The weight percentage of the insoluble pressure-sensitive adhesive component immersed in the wire mesh at 24 ° C. for 24 hours is defined as the gel fraction. However, the weight of the substrate is subtracted.

The thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet, the optical member with the pressure-sensitive adhesive layer, and the double-sided pressure-sensitive adhesive sheet is usually preferably 5 to 3000 μm, particularly preferably 50 to 1000 μm, and more preferably 100 to 500 μm. Preferably there is.
If the thickness of the pressure-sensitive adhesive layer is too thin, the impact absorbability tends to decrease, and if it is too thick, the thickness of the entire optical member tends to increase too much.

In applications where it is necessary to obtain a thick adhesive layer, it is preferable to apply with a film thickness of 100 μm or more, particularly preferably 110 μm or more, more preferably 140 μm or more, and an adhesive obtained after drying. The film thickness of the agent layer is preferably 50 μm or more, particularly preferably 80 μm or more, and further preferably 100 μm or more.
As the upper limit of the film thickness, the film thickness at the time of coating is usually 3000 μm, and the film thickness after drying is usually 2000 μm.
In particular, when used for applications such as shock absorption and air gap filling, the thickness of the pressure-sensitive adhesive layer after drying is preferably 100 μm or more, particularly preferably 120 μm or more. Is usually 2000 μm.

  The adhesive strength of the pressure-sensitive adhesive layer of the present invention is appropriately determined according to the material of the adherend, and is adhered to, for example, a PET sheet on which a glass substrate, a polycarbonate plate, a polymethyl methacrylate plate, or an ITO layer is deposited. In some cases, the adhesive strength is preferably 3 N / 25 mm to 500 N / 25 mm, and more preferably 5 N / 25 mm to 100 N / 25 mm.

  The adhesive strength is calculated as follows. A PET with an adhesive layer in which an adhesive layer with a thickness of 25 μm is formed on a polyethylene terephthalate (PET) sheet with a thickness of 38 μm is cut into a width of 25 mm, the release sheet is peeled off, and the adhesive layer side is covered with the above-mentioned coated layer. The above adhesive sheet of 25 mm × 100 mm was applied to the body by pressurizing and reciprocating 2 kg rubber rollers in an atmosphere of 23 ° C. and 50% relative humidity, and left in the same atmosphere for 30 minutes, and then peeled at a room temperature of 300 mm / min. 180 degree peel strength (N / 25mm) was measured.

  Examples of the electronic device in the present invention include a capacitive touch panel, a capacitance detection type device, a component for electronic paper, and the adhesive of the present invention exhibits a high dielectric constant and a low volume resistivity. In addition, since it is excellent in transparency, it is particularly preferably used for the purpose of bonding members constituting the electronic device.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the examples, “parts” and “%” mean weight basis.

First, various acrylic resins were prepared as follows. In addition, regarding the measurement of the weight average molecular weight of acrylic resin, dispersion degree, and glass transition temperature, it measured according to the above-mentioned method.
In addition, regarding the measurement of a viscosity, it measured according to the 4.5.3 rotational viscometer method of JISK5400 (1990).

[Preparation of acrylic resin (A)]
[Acrylic resin (A-1)]
In a four-necked round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 70 parts of butyl acrylate (a1), 30 parts of 2-hydroxyethyl acrylate (a2) and 100 parts of ethyl acetate were added. After charging and heating under reflux, 0.25 parts of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, reacted at ethyl acetate reflux temperature for 3.5 hours, diluted with ethyl acetate, and then an acrylic resin ( A-1) Solution (weight average molecular weight (Mw) 800,000, dispersity (Mw / Mn) 4.3, glass transition temperature -45 ° C., solid content 35.7%, viscosity 5500 mPa · s (25 ° C.)) Obtained.

[Acrylic resin (A'-1)]
In a 4-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, 94.8 parts of butyl acrylate (a1), 0.2 part of 2-hydroxyethyl acrylate (a2), acrylic Acid 5.0, 100 parts of ethyl acetate and 50 parts of acetone were added, and after heating to reflux, 0.15 part of azobisisobutyronitrile (AIBN) was added as a polymerization initiator and reacted at the solvent reflux temperature for 3.5 hours. Then, it diluted with ethyl acetate, acrylic resin (A'-1) solution (weight average molecular weight (Mw) 1,500,000, dispersity (Mw / Mn) 3.5, glass transition temperature -55 degreeC, solid content 22 0.5% and a viscosity of 8,000 mPa · s (25 ° C.)).

[Monofunctional monomer (B)]
The following were prepared as the monofunctional monomer (B-1).
2-acryloyloxyethyl-2-hydroxyethylphthalic acid (manufactured by Kyoeisha Chemical Co., Ltd., trade name “HOA-MPE)

[Polyfunctional monomer (C)]
The following were prepared as the polyfunctional monomer (C-1).
・ Trimethylolpropane triacrylate (Kyoeisha Chemical Co., Ltd., trade name “TMP-A”)

[Polymerization initiator (D)]
The following were prepared as the photopolymerization initiator (D-1).
A mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone in a mass ratio of 1: 1 (Ciba Specialty Chemicals, “Irgacure 500”)

[Crosslinking agent (E)]
The following were prepared as a crosslinking agent (E-1).
・ 55% ethyl acetate solution of trimethylolpropane tolylene diisocyanate adduct (manufactured by Nippon Polyurethane Co., Ltd., “Coronate L-55E”)

[Examples 1 and 2, Reference Example 1 , Comparative Examples 1 to 4]
Each of the blended components prepared and prepared as described above was blended in the blending ratios shown in Table 1 below to prepare a pressure-sensitive adhesive composition to be a pressure-sensitive adhesive forming material, and this was diluted with ethyl acetate with a viscosity of 2,000 mPa · It diluted to s (25 degreeC), and produced the adhesive composition solution.

Then, the pressure-sensitive adhesive composition solution obtained above is applied to a polyethylene light release sheet so that the thickness after drying is 25 μm, and dried at 90 ° C. for 3 minutes to form a pressure-sensitive adhesive composition layer. The pressure-sensitive adhesive composition layer thus obtained was transferred onto polyethylene-based heavy release (thickness 38 μm).
Next, in Examples 1 to 3 and Comparative Examples 1 to 3, ultraviolet irradiation was performed with an electrodeless lamp [H bulb of LH6UV lamp] manufactured by Fusion Corporation at a peak illuminance of 600 mW / cm ² and an integrated exposure amount of 240 mJ / cm ^2. (120 mJ / cm2 × 2 passes), 23 ° C. × 50% R.D. H. Aged for 10 days under the above conditions to obtain a pressure-sensitive adhesive layer with a double-sided separator.
Further, in Comparative Example 4, UV irradiation was not performed and 23 ° C. × 50% R.D. H. Aged for 10 days under the above conditions to obtain a pressure-sensitive adhesive layer with a double-sided separator

  Using the pressure-sensitive adhesive layer with a double-sided separator thus obtained, volume resistivity and transparency of the pressure-sensitive adhesive layer were measured and evaluated according to the following methods.

[Volume resistivity]
The pressure-sensitive adhesive layer with a double-sided separator was allowed to stand in an atmosphere of 23 ° C. × 50% RH for 24 hours, then cut to 5 cm × 5 cm, and a volume resistivity measuring device (manufactured by Mitsubishi Chemical Analytech Co., Ltd., “Hiresta-UP” MCP-HT450 ") was used to peel one lightly peeled PET and stick an adhesive to a metal plate attached to the apparatus, and then peel the other post-heavy peeled PET and stick it to an electrode, and measure the volume resistivity.
(Evaluation criteria)
◎… Less than 1.0E + 10 ○… 1.0E + 10 or more and less than 5.0E + 10 Δ… 5.0E + 10 or more and less than 1.0E + 11 ×… 1.0E + 11 or more

[transparency]
The separator of the pressure-sensitive adhesive layer with double-sided separator was peeled off on both sides, and the transparency of the obtained pressure-sensitive adhesive layer was visually evaluated. The evaluation criteria are as follows.
(Evaluation criteria)
○… transparent ×… cloudy

It turns out that the adhesive layer which consists of an adhesive of Examples 1-3 has a low volume resistivity and is excellent also in transparency.
On the other hand, the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive described in Comparative Examples 1 to 3 has some low volume resistivity, but the pressure-sensitive adhesive layer becomes cloudy because the compatibility between the acrylic resin and the monomer component is poor. It is inferior in transparency.
Moreover, although the adhesive layer which consists of an adhesive of the comparative example 4 is excellent in transparency, it has a high volume resistivity and is hard to use as an adhesive for electronic devices.

The pressure-sensitive adhesive of the present invention can exhibit a low volume resistivity, and is also excellent in transparency. Therefore, a member constituting a capacitive touch panel, a capacitance detection type device, and a component for electronic paper. This is useful for applications such as bonding.

Claims (8)

The pressure-sensitive adhesive composition [I] containing the acrylic resin (A) and the ethylenically unsaturated monomer (B) containing one ethylenically unsaturated group is cured by active energy rays and / or heat. A pressure sensitive adhesive,
The acrylic resin (A) is an acrylic resin obtained by polymerizing a monomer component containing 15 to 50% by weight of a hydroxyl group-containing monomer,
The ethylenically unsaturated monomer (B) containing one ethylenically unsaturated group has an aromatic ring or an alicyclic ring substituted with two or more substituents, and the ethylenically unsaturated monomer ( the content of B) is Ri 50-300 parts by der per 100 parts by weight of the acrylic resin (a), the
The ethylenically unsaturated monomer (B) having an aromatic ring or an alicyclic ring substituted with two or more substituents is 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropyl Hexahydrohydrogen phthalate, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethyl-2-hydroxyethyl-phthalic acid, 2- (meth) acryloyloxyethyl 2-hydroxypropyl phthalate, 2 -(Meth) acryloyloxypropyl hydrogen phthalate, 2- (meth) acryloyloxypropyl tetrahydrohydrogen phthalate, o-phenylphenol EO modified (meth) acrylate, EO modified cresol (meth) acrylate, EO modified nonylphenol (meth) acrylate, tribromophenol Sulfonyl (meth) acrylate, EO-modified tribromophenyl (meth) acrylate, isobornyl (meth) acrylate, Ru 3,3,5-trimethylcyclohexane (meth) acrylate or 1,4-cyclohexanedimethanol mono (meth) acrylate der, A pressure-sensitive adhesive.   The pressure-sensitive adhesive according to claim 1, wherein the ethylenically unsaturated monomer (B) has a molecular weight of 200 or more.   The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the pressure-sensitive adhesive composition [I] contains an ethylenically unsaturated monomer (C) containing two or more ethylenically unsaturated groups.   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive composition [I] contains a polymerization initiator (D).   The pressure-sensitive adhesive composition [I] contains a crosslinking agent (E) and is crosslinked by a crosslinking agent.   A pressure-sensitive adhesive for electronic devices, comprising the pressure-sensitive adhesive according to claim 1.   An electronic device comprising the pressure-sensitive adhesive for electronic devices according to claim 6. A pressure-sensitive adhesive composition containing an acrylic resin (A) and an ethylenically unsaturated monomer (B) containing one ethylenically unsaturated group, wherein the acrylic resin (A) contains 15 hydroxyl group-containing monomers. An acrylic resin obtained by polymerizing a monomer component containing ˜50% by weight, wherein the ethylenically unsaturated monomer (B) containing one ethylenically unsaturated group is substituted with two or more substituents. and are those having an aromatic ring or alicyclic, and Ri content 50-300 parts by weight der of acrylic resin (a) ethylenically unsaturated monomer to 100 parts by weight (B), 2 or more substituent The ethylenically unsaturated monomer (B) having an aromatic ring or an alicyclic ring substituted with a group is 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydride Hydrogen phthalate, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethyl-2-hydroxyethyl-phthalic acid, 2- (meth) acryloyloxyethyl 2-hydroxypropyl phthalate, 2- ( (Meth) acryloyloxypropyl hydrogen phthalate, 2- (meth) acryloyloxypropyltetrahydrophthalate, o-phenylphenol EO modified (meth) acrylate, EO modified cresol (meth) acrylate, EO modified nonylphenol (meth) acrylate, tribromophenyl (Meth) acrylate, EO-modified tribromophenyl (meth) acrylate, isoboronyl (meth) acrylate, 3,3,5 trimethylcyclohexane (meth) acrylate, or 1,4-cyclohexane dimethyl Ethanol mono (meth) PSA composition, wherein the acrylate der Rukoto.