TWI689567B - Composition for photoreactive transparent adhesive sheet, photoreactive transparent adhesive sheet, touch panel, and image display device - Google Patents

Abstract

The present invention relates to a composition for a photoreactive transparent adhesive sheet which includes a (meth)acrylic resin (A) and a multifunctional (meth)acrylate oligomer (B) in which the weight-average molecular weight is 700 to 10000 and the double bond equivalent between carbon and carbon is 300g/mol or less, wherein the acid number is 0mgKOH/g to 5mgKOH/g.

Description

Composition for photo-reactive transparent adhesive sheet, photo-reactive transparent adhesive sheet, touch panel, image display device

The present invention relates to a composition for a photoreactive transparent adhesive sheet, a photoreactive transparent adhesive sheet obtained from the composition for a photoreactive transparent adhesive sheet, a photoreactive transparent adhesive sheet for fixing a transparent resin board, A fixed photoreactive transparent adhesive sheet of a transparent conductive film, a touch panel with a photoreactive transparent adhesive sheet, and an image display device.

In recent years, in the fields of mobile phone terminals, game consoles, car navigation systems, etc., image display devices such as liquid crystal displays or input devices used in combination with the aforementioned image display devices such as touch panels have been common. These image display devices or input devices use transparent adhesive sheets for bonding to optical parts.

As the touch panel using the transparent adhesive sheet, there can be exemplified: a resistive film type touch panel that detects the pressure at the time of input, and the electrostatic capacitance of the input part is detected by the static electricity from the human body at the time of input Touch panel. The electrostatic capacitive touch panel is fixed in such a way that the conductive layer of a transparent conductive film such as indium tin oxide (ITO) is in contact with the surface of the adhesive layer of the transparent adhesive sheet. Therefore, when the adhesive layer is in contact with the conductive layer of the transparent conductive film, the oxidation reaction of the metal due to the acid component contained in the adhesive may cause a problem of lowering the conductive function. Therefore, the adhesive sheet for fixing the transparent conductive film is required to have high metal corrosion resistance.

In addition, since mobile terminals, game consoles, car navigation systems, etc. are lightweight in terms of portability or handling during operation, or safety in case of breakage, acrylic plates or polycarbonates are often used. A transparent resin board such as a board replaces the glass board as a protective transparent board in front of the touch panel. However, when the transparent resin plates are placed at a high temperature, gas is released from the inside, and the gas causes foaming at the interface between the transparent resin plate and the adhesive sheet. As a result, there is a problem that the visibility is reduced.

Conventionally, as a method for improving the foaming resistance at high temperatures, for example, it is known to homopolymerize a homopolymer into a monomer exhibiting a high glass transition temperature (Tg) or a monomer containing a functional group such as a carboxyl group. Wait to improve the Tg of the adhesive.

For example, it is known that a polymer consisting of a polymer containing a carboxyl group-containing monomer as a constituent and an oligomer containing a monomer containing an amine group as a constituent at room temperature and high temperature for plastic adhesion and foam resistance An adhesive composition having excellent properties (see, for example, Patent Document 1). However, this adhesive composition is an adhesive composition containing a carboxyl group-containing polymer, and since it contains an acid component, it has a problem that it cannot be used for lamination of a transparent conductive film.

In addition, in order to satisfy the foaming resistance at high temperatures even if it does not contain acrylic acid and other carboxyl group-containing monomer components, an adhesive composition containing an acrylic polymer of a specific structure and a photoreactive monomer is known (See, for example, Patent Document 2). However, the adhesive sheet formed from the adhesive composition has high adhesive strength at high temperature after photoreaction and excellent foaming resistance, but low adhesive force before photoreaction, so the initial adhesion Is low and has a problem of poor workability.

The current status quo is still unavailable: "An excellent adhesive composition that has excellent foaming resistance at high temperatures and has both high corrosion resistance and adhesion at a high level." In other words, a transparent adhesive sheet excellent in foaming resistance at high temperature and high humidity and excellent in corrosion resistance is strongly desired.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 10-310754

[Patent Document 2] Japanese Unexamined Patent Publication No. 2014-156552

The present invention is made in view of the above circumstances, and the object of the present invention is to provide a transparent resin board that does not corrode the conductive layer even if it is directly bonded to the conductive layer of the transparent conductive film, and is further used in acrylic boards, polycarbonate boards, etc. When fixed, the adhesion at the initial bonding time is good, and the foaming resistance at high temperature and high humidity is excellent. The composition of the light-reactive transparent adhesive sheet Objects, light-reactive transparent adhesive sheets, touch panels and image display devices provided with light-reactive transparent adhesive sheets.

Based on the aforementioned problems of the transparent adhesive sheet for touch panels, the inventors have repeatedly reviewed the results and found that they contain (meth)acrylic resin, a polyfunctional with a specific molecular weight and a carbon-carbon double bond equivalent ( The light-reactive transparent adhesive sheet obtained from the composition of the light-reactive transparent adhesive sheet of meth)acrylate oligomer, its transparency, adhesiveness, metal corrosion resistance of the transparent conductive film, and the time of fixing the transparent resin plate The foaming resistance is excellent, and the present invention has been completed.

[1]. A composition for a photoreactive transparent adhesive sheet, characterized by comprising (A) (meth)acrylic resin, and (B) a weight average molecular weight of 700 to 10000 and a carbon-carbon double bond equivalent of 300 g/ The polyfunctional (meth)acrylate oligomer below mol has an acid value of 0mgKOH/g~5mgKOH/g.

[2]. The composition for a light-reactive transparent adhesive sheet as described in [1] above, wherein the content of the (A) (meth)acrylic resin is 70% by mass to 95% by mass, and the (B) is polyfunctional The content of (meth)acrylate oligomer is 5% by mass to 30% by mass, relative to that of (A) (meth)acrylic resin and (B) multifunctional (meth)acrylate oligomer The total amount is 100 parts by mass, including 0.2 to 5 parts by mass of (C) photopolymerization initiator.

[3]. The composition for a light-reactive transparent adhesive sheet according to [1] or [2] above, wherein the (B) multifunctional (meth)acrylate oligomer is a polymer Ester acrylate oligomer.

[4]. The composition for a light-reactive transparent adhesive sheet according to any one of the above [1] to [3], wherein the (A) (meth)acrylic resin contains 5 mol% to 10 mol% of The structural unit of (meth)acrylic monomer of hydroxyl group.

[5]. A photo-reactive transparent adhesive sheet characterized by the composition for a photo-reactive transparent adhesive sheet according to any one of the above [1] to [4].

[6]. A photo-reactive transparent adhesive sheet for fixing a transparent resin plate, characterized by the photo-reactive transparent adhesive sheet of [5] above.

[7]. A photo-reactive transparent adhesive sheet for fixing a transparent conductive film, which is characterized by the photo-reactive transparent adhesive sheet of the aforementioned [5].

[8]. A touch panel characterized by having the hardened product of the photo-reactive transparent adhesive sheet of any one of the above [5] to [7].

[9]. An image display device characterized by being provided with a cured product of the photoreactive transparent adhesive sheet of any one of the above [5] to [7].

According to the present invention, the composition for a photoreactive transparent adhesive sheet contains a (meth)acrylic resin, a polyfunctional (meth)acrylate oligomer having a specific molecular weight and a carbon-carbon double bond equivalent, and can provide transparency , Adhesiveness, and foaming resistance of the transparent resin board during fixing are excellent light reactivity Transparent adhesive sheet. Furthermore, by setting the acid value of the composition for a photoreactive transparent adhesive sheet to a specified amount or less, the corrosion of the conductive layer of the transparent conductive film due to the acid component can be suppressed. Therefore, the light-reactive transparent adhesive sheet of the present invention has good recognizability, so it can be suitably used in touch panels or image display devices.

[Best form for carrying out the invention]

An embodiment of the composition for a light-reactive transparent adhesive sheet of the present invention, a light-reactive transparent adhesive sheet, a touch panel, and an image display device will be described.

The present embodiment is specifically described in order to better understand the gist of the present invention, and the present invention is not limited unless otherwise specified.

Moreover, in this specification, the so-called "(meth)acrylic acid" means acrylic acid or methacrylic acid; the so-called "(meth)acrylate" means acrylate or methacrylate; the so-called "(meth)acrylic acid""Acryloyl" means "acryloyl (CH ₂ =CH-CO-) or methacryloyl (CH ₂ =C(CH ₃ )-CO-).

[Composition for Photoreactive Transparent Adhesive Sheet]

The composition for a photoreactive transparent adhesive sheet of the present invention comprises (A) (meth)acrylic resin, and (B) a weight average molecular weight of 700 to 10000 and a carbon-carbon double bond equivalent of 300 g/mol or less Multifunctional (meth)acrylate oligomer, acid value is 0mgKOH/g~5mgKOH/g.

"(A) (meth)acrylic resin"

The (A) (meth)acrylic resin is not particularly limited as long as it is a resin obtained by polymerizing a monomer having a (meth)acryloyl group at 50 mol% or more as a main component.

The (meth)acrylic monomer (monomer having a (meth)acryloyl group) that can be used for the synthesis of (A) (meth)acrylic resin is not particularly limited, but it preferably contains no carboxyl group (chemical formula: -COOH). When a (meth)acrylic monomer containing a carboxyl group is used, the structural unit derived from the (meth)acrylic monomer containing a carboxyl group in (A) (meth)acrylic resin is preferably 0.5 mol% or less, and is more preferable 0.1mol% or less.

Examples of (meth)acrylic monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, (meth) N-butyl acrylate, third butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, iso (meth) acrylate Octyl ester, lauryl (meth)acrylate, isodecyl (meth)acrylate, stearyl (meth)acrylate, tridecyl (meth)acrylate, isostearyl (meth)acrylate, etc. Alkyl (meth)acrylate, cyclohexyl (meth)acrylate, norbornyl (meth)acrylate, isobornyl (meth)acrylate, norbornene (meth)acrylate, (meth)acrylic acid Dicyclopentenyl ester, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, tricyclodecane dimethylol Cyclic alkyl (meth)acrylate such as dimethacrylate, methoxyethyl (meth)acrylate, (meth)acrylic acid Ethoxyethyl, butoxyethyl (meth)acrylate, 2-methoxyethoxyethyl (meth)acrylate, 2-ethoxyethoxyethyl (meth)acrylate, etc. Alkoxyalkyl (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate Alkoxy (poly) alkanediol (meth)acrylates such as esters, fluorinated alkyl (meth)acrylates such as octafluoropentyl (meth)acrylate, N,N-di (meth)acrylate Dialkylaminoalkyl (meth)acrylate such as methylaminoethyl, N,N-diethylaminoethyl (meth)acrylate, (meth)acrylamide, diacetone (Meth) Acrylic amine and other amide group-containing (meth) acrylate, glycidyl (meth) acrylate and other epoxy group-containing (meth) acrylate, polysiloxane modified (meth) Acrylate, polyethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate , Multifunctional (meth)acrylates such as tripropylene glycol di(meth)acrylates. These (meth)acrylic monomers may be used alone or in combination of two or more.

(A) The (meth)acrylic resin preferably contains 5 to 10 mol% of structural units derived from hydroxyl-containing (meth)acrylate monomers, and more preferably contains 6 to 9 mol%.

(A) The (meth)acrylic resin contains 5 mol% to 10 mol% of structural units derived from hydroxyl-containing (meth)acrylate monomers, which can suppress the whitening of the photoreactive transparent adhesive sheet in a hot and humid environment .

The hydroxyl group-containing (meth)acrylate monomer is preferably one that does not have a carboxyl group, and for example, an alkyl group having 2 to 7 carbon atoms (methyl) Hydroxyalkyl acrylate, etc. Examples of such specific examples include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and (meth)acrylic acid 1. 3-Butanediol ester, 1,4-butanediol (meth)acrylate, 1,6-hexanediol (meth)acrylate, 3-methylpentanediol (meth)acrylate, etc. These can be used alone or in combination of two or more.

In addition, as long as the polymerizability is not impaired, other polymerizable monomers may be used as the copolymerization component in the (A) (meth)acrylic resin. Examples of such a polymerizable monomer include acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, and vinylidene Vinyl chloride, alkyl vinyl ether, vinyl toluene, N-vinyl pyridine, N-vinyl pyrrolidone, dialkyl itaconate, dialkyl fumarate, allyl alcohol, propylene amide Chlorine, methyl vinyl ketone, N-acrylamide methyl trimethyl ammonium chloride, allyl trimethyl ammonium chloride, dimethyl allyl vinyl ketone, etc.

(A) The molecular weight of the (meth)acrylic resin is not particularly limited, and it is preferably 100,000 to 2 million in terms of weight average molecular weight, and more preferably 200,000 to 1 million.

As long as the (A) (meth)acrylic resin has a weight average molecular weight of 200,000 to 2 million, the cohesion of the resulting photoreactive transparent adhesive sheet will be sufficient.

Here, the so-called "weight average molecular weight" is measured using colloidal permeation chromatography (Showa Denko Corporation Shodex (registered trademark) GPC-101) at room temperature under the following conditions, converted to polystyrene The calculated value.

Column: Shodex (registered trademark) LF-804, manufactured by Showa Denko

Column temperature: 40℃

Sample: 0.2 mass% tetrahydrofuran solution of (meth)acrylic resin

Flow rate: 1ml/min

Dissolution solution: tetrahydrofuran

Detector: RI detector

The glass transition point (Tg) of (A) (meth)acrylic resin is not particularly limited, but it is preferably -80°C to 0°C, and more preferably -70°C to -5°C.

As long as the glass transition point (Tg) of (A) (meth)acrylic resin is within the range of -80°C to 0°C, the resulting light-reactive transparent adhesive sheet has sufficient adhesive force.

Still, the glass transition point (Tg) of (A) (meth)acrylic resin can be appropriately adjusted by changing the type of monomer component or the blending ratio used during polymerization.

Here, the "glass transition temperature (Tg) of the photoreactive transparent adhesive sheet" can be obtained by the following method. That is, a 10 mg sample was taken from the photoreactive transparent adhesive sheet, and a differential scanning calorimeter (DSC) was used to perform a differential scanning until the temperature was changed from -80°C to 200°C at a heating rate of 10°C/min. For calorie measurement, the endothermic start temperature due to glass transition is set to the glass transition point (Tg). Still, if two glass transition points (Tg) are observed, the average value of the two glass transition points (Tg) is set to (A) the glass transition point (Tg) of (meth)acrylic resin.

(A) The polymerization method of (meth)acrylic resin is not particularly limited For the preparation, known methods such as solution polymerization, emulsification polymerization, bulk polymerization, suspension polymerization, and alternating copolymerization can be used. Among these, solution polymerization is particularly suitable in terms of transparency and water resistance of the obtained polymer.

In addition, the copolymer obtained may be a random copolymer, a block copolymer, or the like.

(A) The polymerization initiator used in the polymerization of (meth)acrylic resin is not particularly limited, and can be appropriately selected and used from known materials. Examples of the polymerization initiator include 2,2′-azobis(isobutyronitrile), 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2 ,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1 -Carbonitrile), 2,2'-azobis(2,4,4-trimethylpentane), dimethyl-2,2'-azobis(2-methylpropionate), etc. Azo polymerization initiator, or benzoyl peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, dicumyl peroxide, 1 Peroxide polymerization of 1,1-bis(third butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis(third butylperoxy)cyclododecane, etc. Oil-soluble polymerization initiator such as initiator. These polymerization initiators may be used alone or in combination of two or more.

The use amount of the polymerization initiator is not particularly limited. For example, it is preferably 0.01 to 5 parts by mass, more preferably 0.015 to 4 parts by mass, and more preferably 0.02 parts by mass relative to 100 parts by mass of the monomer. 3 parts by mass.

By controlling the amount of initiator that decomposes per unit time, the molecular weight of (meth)acrylic resin can be controlled. For example, if you want to make the molecular weight small, at least choose: increase the amount of initiator used, or use a lower decomposition temperature Any one of the initiators can be implemented. If the molecular weight is to be high, at least one of: reducing the amount of the initiator used or using an initiator with a high decomposition temperature may be used.

The polymerization temperature of the (meth)acrylic resin is not particularly limited, and considering the ease of control in manufacturing, it is preferably 30°C to 110°C, and more preferably 50°C to 100°C.

In addition, the polymerization time is preferably 2 hours to 12 hours in consideration of easy control in manufacturing.

Still, various general solvents can be used for solution polymerization. Examples of such solvents include esters such as ethyl acetate, n-propyl acetate, and n-butyl acetate, aromatic hydrocarbons such as toluene and xylene, and aliphatic hydrocarbons such as n-hexane and n-heptane. Organic solvents such as alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, and ketones such as methyl ethyl ketone and methyl isobutyl ketone. These solvents may be used alone or in combination of two or more.

Moreover, in the composition for photoreactive transparent adhesive sheets of the present invention, the content of (A) (meth)acrylic resin is preferably 70% by mass to 95% by mass, and more preferably 75% by mass to 90% by mass .

As long as the content of (A) (meth)acrylic resin is within the above range, the resulting photoreactive transparent adhesive sheet will have a sufficiently large adhesive force before photoreaction.

"(B) Multifunctional (meth)acrylate oligomer"

(B) The multifunctional (meth)acrylate oligomer has the following effects: The resulting photoreactive transparent adhesive sheet is used to fix the transparent resin plate to When an object such as a glass substrate or a resin film is applied, foaming from the transparent resin plate is suppressed. More specifically, the (B) multifunctional (meth)acrylate oligomer system adheres the photoreactive transparent adhesive sheet to the transparent resin plate, and then irradiates the active energy ray to make the photoreactive transparent adhesive sheet The multifunctional (meth)acrylate oligomer produces a light reaction, which enhances the adhesion between the transparent resin plate and the adhesive sheet, thereby suppressing foaming.

(B) The polyfunctional (meth)acrylate oligomer system has a weight average molecular weight of 700 to 10000 and a carbon-carbon double bond equivalent of 300 g/mol or less. (B) The polyfunctional (meth)acrylate oligomer preferably has a weight average molecular weight of 800 to 5000 and a carbon-carbon double bond equivalent of 80 g/mol to 250 g/mol; and further preferably: the weight average molecular weight is 900-2500 and the carbon-carbon double bond equivalent is 90g/mol~220g/mol; more preferably: the weight average molecular weight is 1000~2000 and the carbon-carbon double bond equivalent is 100g/mol~200g/mol.

The "multifunctional" in this specification means that the oligomer has a plurality of ethylenic carbon-carbon double bonds; the so-called "carbon-carbon double bond equivalent" means that it will have carbon-carbon double bonds. The value obtained by dividing the mass per 1 mol of the compound by the number of carbon-carbon double bonds in the compound.

(B) If the weight average molecular weight of the multifunctional (meth)acrylate oligomer is less than 700, the resulting photo-reactive transparent adhesive sheet will have less adhesive force before photo-reaction, and the resulting photo-reactive transparent The foam resistance of the adhesive sheet after light reaction will be insufficient. On the other hand, if the weight-average molecular weight of the (B) multifunctional (meth)acrylate oligomer exceeds 10,000, the compatibility with the (A) (meth)acrylic resin will deteriorate, and the resulting photoreactivity will be transparent The transparency of the adhesive sheet will be insufficient.

Also, when the carbon-carbon double bond equivalent of (B) multifunctional (meth)acrylate oligomer is outside the above range, the resulting light-reactive transparent adhesive sheet will have insufficient foaming resistance after light reaction .

Examples of (B) polyfunctional (meth)acrylate oligomers include polyester acrylate oligomers, urethane acrylate oligomers, and epoxy acrylate oligomers. Among these, in terms of the adhesive force of the obtained photoreactive transparent adhesive sheet, a polyester acrylate oligomer is preferred.

Specific commercial products of polyester acrylate oligomers include, for example, V # 1000 (trade name), V # 1020 (trade name) manufactured by Osaka Organic Industries Co., Ltd., CN2300 (trade name) manufactured by Sartomer, and CN2301. (Brand name), CN2302 (brand name), CN2303 (brand name), CN2304 (brand name), EBECRYL (registered trademark) 450, EBECRYL (registered trademark) 810, EBECRYL (registered trademark) 846, manufactured by Daicel-Allnex Corporation, EBECRYL (registered trademark) 1830, EBECRYL (registered trademark) 1870, etc.

Specific commercially available products of urethane acrylate oligomers include, for example, EBECRYL (registered trademark) 220, EBECRYL (registered trademark) 1290, EBECRYL (registered trademark) 8254, KRM8200 (products) manufactured by Daicel-Allnex Corporation. Name), KRM8452 (trade name), etc.

Specific commercial products of epoxy acrylate oligomers include, for example, EBECRYL (registered trademark) 860 manufactured by Daicel-Allnex Corporation.

These (B) multifunctional (meth)acrylate oligomers may be used alone or in combination of two or more.

Further, in the composition for a photoreactive transparent adhesive sheet of the present invention, the content of (B) polyfunctional (meth)acrylate oligomer is preferably 5% by mass to 30% by mass, and more preferably 10% by mass %~20% by mass.

As long as the content of the (B) multifunctional (meth)acrylate oligomer is within the above range, the resulting photoreactive transparent adhesive sheet can fully exhibit foam resistance after photoreaction (photocuring).

The composition for a photoreactive transparent adhesive sheet of the present invention containing (A) (meth)acrylic resin and (B) multifunctional (meth)acrylate oligomer, its acid value is 0 mgKOH/g~5 mgKOH/g , Preferably 0mgKOH/g~1mgKOH/g, more preferably 0mgKOH/g~0.3mgKOH/g, more preferably 0mgKOH/g~0.1mgKOH/g.

When the acid value of the photoreactive transparent adhesive sheet composition exceeds 5 mgKOH/g, it will be difficult to suppress corrosion of the conductive layer of the transparent conductive film. In addition, the acid value of the composition for photoreactive transparent adhesive sheets of the present invention is a value measured in accordance with JIS K0070. The acid value of the composition for photoreactive transparent adhesive sheets of the present invention can be measured as follows, for example.

Use a precision scale to weigh about 2g of the fine-scale sample in a 100ml Erlenmeyer flask, add 10ml of a mixed solvent of ethanol/diethyl ether = 1/1 (mass ratio) and dissolve it. Further add 1 to 3 drops of phenolphthalein ethanol solution as an indicator to the container, and stir thoroughly until the sample becomes uniform. It was titrated with 0.1N potassium hydroxide-ethanol solution, and the light red color of the indicator lasted for 30 seconds, which was regarded as the end point of neutralization. From this result, the value obtained using the following formula (1) was set as the acid value of the composition for a photoreactive transparent adhesive sheet.

Acid value (mgKOH/g)=[B×f×5.611]/S (1)

(In the formula, B is the usage amount (ml) of the 0.1N potassium hydroxide-ethanol solution, f is the factor of the 0.1N potassium hydroxide-ethanol solution, and S is the sample amount (g)).

"(C) Photopolymerization Initiator"

The composition for a photoreactive transparent adhesive sheet of the present invention is made into a photoreactive transparent adhesive sheet, and (B) a polyfunctional (meth)acrylate oligo in the photoreactive transparent adhesive sheet with active energy rays The polymer produces a photoreaction and preferably further contains (C) a photopolymerization initiator.

The (C) photopolymerization initiator is not particularly limited, and known ones can be used. Examples of the (C) photopolymerization initiator include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, benzoyl dimethyl ketal, 4 -(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2-morpholino (4-thiomethyl) Phenyl)propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-[4- (1-methylvinyl) phenyl] acetophenones such as acetone oligomers; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin Benzoins such as isobutyl isobutyl ether; benzophenone, methyl o-benzoyl benzoate, 4-phenyl benzophenone, 4-benzoyl-4'-methyl-diphenyl Thioether, 3,3',4,4'-tetrakis(tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzophenone-N, N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl] benzyl ammonium bromide, (4-benzylbenzyl) trimethyl Benzophenones such as ammonium chloride; 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone , 1-chloro-4-propoxythioxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-one meso Thioxanthones such as chloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-tris Acyl phosphine oxides such as methyl-pentyl phosphine oxide, bis(2,4,6-trimethylbenzyl amide)-diphenyl phosphine oxide, etc. Among these (C) photopolymerization initiators, in terms of transparency, bis(2,4,6-trimethylbenzoyl)-diphenylphosphine oxide and 1-hydroxyl are preferably used At least one of cyclohexyl phenyl ketones.

These (C) photopolymerization initiators may be used alone or in combination of two or more.

In addition, in the composition for a photoreactive transparent adhesive sheet of the present invention, the content of (C) photopolymerization initiator is relative to (A) (meth)acrylic resin and (A) in terms of photoreactivity. B) The total amount of polyfunctional (meth)acrylate oligomers 100 parts by mass is preferably 0.2 parts by mass to 5 parts by mass, more preferably 0.5 parts by mass to 3 parts by mass, more preferably 0.8 parts by mass to 2 Quality parts.

As long as the content of the (C) photopolymerization initiator is 0.2 parts by mass or more, the photocurability of the obtained photoreactive transparent adhesive sheet will be sufficient. On the other hand, as long as the content of the (C) photopolymerization initiator is 5 parts by mass or less, the resulting photoreactive transparent adhesive sheet can exhibit sufficient heat-resistant yellow modification.

If (A) (meth)acrylic resin has functional groups such as hydroxyl group or carboxyl group, the cohesion of the resulting photoreactive transparent adhesive sheet is improved For the purpose of power, the composition for a photoreactive transparent adhesive sheet of the present invention may also contain a crosslinking agent having a plurality of functional groups that can react with the (A) (meth)acrylic resin. Examples of the crosslinking agent include polyfunctional melamine compounds, polyfunctional epoxy compounds, and polyfunctional isocyanate compounds.

Examples of the multifunctional melamine compound include methylated trimethylol melamine, butylated hexamethylol melamine, and the like.

Examples of the multifunctional epoxy compound include diglycidyl aniline, N,N,N',N'-tetraglycidyl-1,3-phenylenedi(methylamine) 4,4'-methylene Bis(N,N-diglycidylaniline), N,N'-(cyclohexane-1,3-diylbismethylene)bis(diglycidylamine), glycerol diglycidyl ether, etc. .

Examples of the multifunctional isocyanate compound include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 2-methyl-1,5-pentane diisocyanate, 3 -Methyl-1,5-pentane diisocyanate, isophorone diisocyanate, cyclohexyl diisocyanate, toluene diisocyanate (TDI), hydrogenated toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate , The reaction product of trimethylolpropane and toluene diisocyanate, the reaction product of trimethylolpropane and hexamethylene diisocyanate, polyether polyisocyanate, polyester polyisocyanate, hydrogenated xylene diisocyanate, hydrogenated tetraisocyanate Methylxylene diisocyanate, etc.

When the (A) (meth)acrylic resin has a hydroxyl group, among these crosslinking agents, a polyfunctional isocyanate compound is preferable in terms of reactivity (curing rate).

The amount of crosslinking agent used is not particularly limited, but for example, relative to (A) 100 parts by mass of (meth)acrylic resin, preferably 0.1 parts by mass to 10 parts by mass, more preferably 0.2 parts by mass to 9 parts by mass, more preferably 0.5 parts by mass to 8 parts by mass.

As long as the amount of the crosslinking agent used is at least 0.1 parts by mass, the cohesive force of the resulting photoreactive transparent adhesive sheet will be sufficient. On the other hand, as long as the amount of the crosslinking agent used is 10 parts by mass or less, the resulting photoreactive transparent adhesive sheet will not become too hard.

In the composition for a photo-reactive transparent adhesive sheet of the present invention, in order to increase the adhesive force of the resulting photo-reactive transparent adhesive sheet as needed, it can be within a range that does not reduce the transparency of the photo-reactive transparent adhesive sheet Add adhesion to the resin.

Examples of the adhesion-imparting resin include rosin-based resins such as rosin or esters of rosin; terpene-based resins such as diterpene polymers or α-pinene-phenol copolymers; aliphatic (C5 series) or aromatic ( Petroleum resins such as C9); other styrene resins, phenol resins, xylene resins, etc. Among these, from the viewpoint of light resistance, hydrogenated rosin with a small number of unsaturated double bonds or esterified products of uneven rosin, or aliphatic or aromatic petroleum resins, etc. are preferred.

In the composition for a photoreactive transparent adhesive sheet of the present invention, the addition amount of the adhesion-imparting resin is preferably 1% by mass to 10% by mass.

In addition, the composition for a light-reactive transparent adhesive sheet of the present invention may contain well-known additives as long as it does not impair transparency.

As additives, plasticizers, surface lubricants, leveling agents, Softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, benzotriazoles and other light stabilizers, phosphate esters and other flame retardants, surfactants, antistatic agents , Dyes, etc.

The composition for a photoreactive transparent adhesive sheet of the present invention may contain an organic solvent for the purpose of adjusting the viscosity during coating.

Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, n-propanol, and isopropanol.

These organic solvents may be used alone or in combination of two or more.

The composition for a photoreactive transparent adhesive sheet according to the present invention can provide transparency by including a (meth)acrylic resin, a multifunctional (meth)acrylate oligomer having a specific molecular weight and a carbon-carbon double bond equivalent Properties, adhesiveness, and foaming resistance during the fixing of transparent resin plates are excellent light-reactive transparent adhesive sheets. In addition, according to the composition for a photoreactive transparent adhesive sheet of the present invention, by setting the acid value to a specified amount or less, the corrosion of the conductive layer of the transparent conductive film due to the acid component can be suppressed.

[Photoreactive transparent adhesive sheet]

The photoreactive transparent adhesive sheet of the present invention is made of the above-mentioned composition for photoreactive transparent adhesive sheet.

That is, the photoreactive transparent adhesive sheet of the present invention is obtained by thinning the composition for the photoreactive transparent adhesive sheet. The "photoreactive transparent adhesive sheet" in this manual means that the The composition for the photoreactive transparent adhesive sheet in the state before the photoreaction (photocuring) is thinned.

The light-reactive transparent adhesive sheet of the present invention can be used for bonding optical members (for bonding optical members) or for manufacturing optical products. The photoreactive transparent adhesive sheet of the present invention is interposed between the first object and the second object, and the two are bonded together to perform light irradiation to harden the photoreactive adhesive sheet, thereby making it possible The first object and the second object are fixed.

In addition, the light-reactive transparent adhesive sheet of the present invention may be a substrate having a substrate, or may be a two-sided adhesive sheet formed only of an adhesive layer without a substrate.

The optical member is not particularly limited as long as it has optical characteristics, and examples thereof include members constituting image display devices, touch panels, and the like, and members used in such devices.

As a member having optical characteristics, specific examples include polarizing plates, retardation plates, optical compensation films, brightness enhancement films, light guide plates, reflective films, anti-reflection films, transparent conductive films, pattern films, decorative films, surface protective films , 珜鏡, lens, color filter, transparent substrate, or even laminated components.

The photoreactive transparent adhesive sheet of the present invention can be obtained by dissolving the above composition for a photoreactive transparent adhesive sheet in a solvent, applying the obtained solution to a release film, and applying the solution after coating Heat and dry, and react with the hydroxyl group of (A) (meth)acrylic resin and the isocyanate group of the cross-linking agent as necessary United.

The thickness of the photoreactive transparent adhesive sheet is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, and still more preferably 15 μm to 100 μm.

As long as the thickness of the photoreactive transparent adhesive sheet is 5 μm or more, the photoreactive transparent adhesive sheet can be easily attached. On the other hand, as long as the film thickness of the photoreactive transparent adhesive sheet is 200 μm or less, the photoreaction can be sufficiently performed to the deep part.

In addition, when forming the photoreactive transparent adhesive sheet of the present invention, a well-known coating method can be used as a method of coating (coating) the composition for a photoreactive transparent adhesive sheet. Examples of known coating methods include gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, blade coater, and spray coating. Cloth applicators, comma coaters, direct coaters, etc. are conventional methods of using applicators.

[Photoreactive transparent adhesive sheet for fixing transparent resin board]

The photoreactive transparent adhesive sheet of the present invention can be suitably used for fixing a transparent resin board. The photoreactive transparent adhesive sheet of the present invention can be used for (meth)acrylic resin, polycarbonate resin, polyethylene terephthalate resin board, etc. used in protective panels of image display devices, touch panels, etc. It can be fixed and can suppress foaming under high temperature and high humidity.

As a specific example of the use of the photoreactive transparent adhesive sheet of the present invention, the following may be mentioned: the composition of the photoreactive transparent adhesive sheet of the present invention is formed into a sheet shape on a release film, cut into an appropriate shape and pasted Combined with the object, irradiate the active energy rays in this state to react the (B) multifunctional (meth)acrylate oligomer in the composition for the photoreactive transparent adhesive sheet, thereby making the photoreactive The transparent adhesive sheet firmly adheres to the object. Examples of active energy rays include ultraviolet light, visible light, and infrared light, and ultraviolet light is particularly preferable in terms of reactivity. As a method of irradiating active energy rays, for example, a metal halide lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, a black light lamp, an LED lamp, etc. are used as light sources, which can irradiate light with an exposure amount of 50mJ/cm ² ~10000mJ/cm ² by light irradiation Make the photoreactive transparent adhesive sheet into a hardened product. Since the cured product of the photoreactive transparent adhesive sheet of the present invention is firmly adhered to the object, foaming at high temperature and high humidity can be suppressed. Therefore, the laminate in which the cured product of the photoreactive transparent adhesive sheet of the present invention and the transparent resin plate are closely adhered can be suitably used as a touch panel.

[Photoreactive transparent adhesive sheet for fixing transparent conductive film]

The light-reactive transparent adhesive sheet of the present invention can be suitably connected to the conductive layer of the transparent conductive film, and is not prone to corrosion of the conductive layer. Therefore, the laminate formed by adhering the photoreactive transparent adhesive sheet of the present invention and the conductive layer of the transparent conductive film can be suitably used as a touch panel.

The transparent conductive film to which the photoreactive transparent adhesive sheet of the present invention is applied is not particularly limited as long as it has a conductive layer on at least one surface layer, and it can be exemplified by vapor deposition or coating of a conductive substance on the surface layer of a transparent substrate Set transparent conductive film.

In the conductive layer of the transparent conductive film, the conductive substance after evaporation or coating is not Particular limitation is exemplified by silver, indium tin oxide, indium oxide, tin oxide, zinc oxide, cadmium oxide, gallium oxide, titanium oxide, and the like. In terms of excellent transparency and conductivity, such medium silver and indium tin oxide are preferred.

The transparent conductive film is not particularly limited as a base material deposited or coated with a conductive substance, and examples thereof include glass and resin films.

Since the photo-reactive transparent adhesive sheet of the present invention is made of the above-mentioned composition for a photo-reactive transparent adhesive sheet, the transparency, adhesiveness, and foam resistance at the time of fixing a transparent resin plate are excellent. In addition, according to the photoreactive transparent adhesive sheet of the present invention, since the acid value is equal to or less than the specified amount, corrosion of the conductive layer of the transparent conductive film due to the acid component can be suppressed. Furthermore, since the hardened system of the photoreactive transparent adhesive sheet of the present invention has good visibility, it can be suitably used for bonding components constituting a touch panel or an image display device.

[Touch Panel]

The touch panel of the present invention is provided with the above-mentioned light-reactive transparent adhesive sheet. The touch panel of the present invention is provided with a light-reactive transparent adhesive sheet, which is used to bond members constituting the touch panel.

[Image display device]

The image display device of the present invention includes the photoreactive transparent adhesive sheet. The image display device of the present invention is provided with a light-reactive transparent adhesive sheet, which is for bonding the members constituting the image display device. As the image display device, there can be exemplified a liquid crystal display device, organic EL (electroluminescence) Optical element) display device, PDP (plasma display panel), electronic paper, etc.

[Example]

Hereinafter, the present invention will be described more specifically by examples and comparative examples, but the present invention is not limited to the following examples.

[Synthesis of (meth)acrylic resin (A-1) to (A-3)]

A reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirring device was fed with 150 g of n-propyl acetate, 97.7 g (0.53 mol) of 2-ethylhexyl acrylate, and 38.0 g (0.38 mol) of methyl methacrylate , Isobornyl acrylate 16.7g (0.08mol), 2-hydroxyethyl methacrylate 1.3g (0.01mol), 2,2'-azobis (isobutyronitrile) 0.15g, 95°C in a nitrogen stream Polymerization treatment was carried out for 8 hours to obtain a (meth)acrylic copolymer (A-1) having a weight average molecular weight of 200,000.

The measurement of the weight average molecular weight of the (meth)acrylic copolymer (A-1) is carried out by the method described above.

Furthermore, except that the composition ratio of the monomer containing (meth)acryloyl group described in Table 1 was changed, it was operated in the same manner as the synthesis method of (meth)acrylic copolymer (A-1) to obtain (meth)acrylic acid Copolymer (A-2), (meth)acrylic copolymer (A-3). These are random copolymers, which can be confirmed by ¹ H-NMR spectrum: "The structural unit of the resulting (meth)acrylic copolymer is slightly higher than the feed ratio of the (meth)acrylate monomer used. the same".

In addition, the same operation as the (meth)acrylic copolymer (A-1) was also performed for the (meth)acrylic copolymer (A-2) and the (meth)acrylic copolymer (A-3) Determination of weight average molecular weight. The results are shown in Table 1.

[Examples 1 to 7 and Comparative Examples 1 to 4]

Prepare the (A) (meth)acrylic resin, (B) multifunctional (meth)acrylate oligomer, crosslinking agent, (C) photopolymerization initiator as shown in Table 2 The solid content concentration of ethyl acetate was adjusted to 40% by mass, and the resulting solution was mixed at room temperature using a disperser, thereby obtaining a composition for a photoreactive transparent adhesive sheet.

[1] Production of photoreactive transparent adhesive sheet (adhesive sheet)

Peeling treatment (polysilicon) of the separator film subjected to peeling treatment (polysilicon coating) on one side of polyethylene terephthalate (PET) film with a thickness of 50 μm On the surface of oxygen coating, the composition for the photoreactive transparent adhesive sheet was cast-coated (coating layer thickness 125 μm) so that the thickness after drying became 50 μm, at 80° C. for 5 minutes and at 110° C. for 10 minutes Heat and dry to form an adhesive layer. Furthermore, the peeling treatment (polysilicon coating) surface side of the separator film subjected to the peeling treatment (polysilicon coating) on one side of the 38 μm thick PET film was covered on the adhesive layer side. Then, aging was carried out at 40° C. for 72 hours to produce a 300 mm×200 mm photoreactive transparent adhesive sheet (adhesive sheet) having a substrate-free type and a separator on both sides.

The following evaluation was performed about the obtained photoreactive transparent adhesive sheet.

[2] acid value

The acid value of each composition for photoreactive transparent adhesive sheets was measured by the method described above. The results are shown in Table 2.

[3] Resistance value of indium tin oxide film

After cutting the adhesive sheet to a size of 50 mm×50 mm, the peeled PET film (separation film) with a thickness of 50 μm was peeled off. The transparent adhesive sheet from which the peeled PET film (partition film) was peeled off was attached to the center of the ITO film of the 100 mm×100 mm ITO film-deposited PET film to form a laminate.

Using a resistivity meter Loresta (registered trademark) GP (manufactured by Mitsubishi Chemical Corporation), the resistance R1 between the two ends of the pair of transparent adhesive sheets to which the transparent adhesive sheet is attached is measured at the center of the ITO film.

The results are shown in Table 2.

Next, the laminate was placed in an environment of 60°C and 90% RH for 500 hours, and then placed in an environment of 23°C and 50% RH for 1 hour, and the resistance R2 was measured in the same manner as the resistance R1. Furthermore, the resistance increase rate [%] of the ITO film was calculated by the following formula (2).

Resistance increase rate [%]=(R2-R1)/R1×100 (2)

When the rate of increase of the resistance is smaller, it means that the corrosion of the conductive film is suppressed. Still, the case where the increase rate of the resistance of the ITO film is less than 5% is judged as "○", and the case where the increase rate of the resistance of the ITO film is more than 5% and less than 10% is judged as "△", and the ITO film The case where the increase rate of the resistance is 10% or more is judged as “×”. The results are shown in Table 2.

[4] Adhesive force of adhesive sheet

Cut the adhesive sheet obtained in the above [1] into a size of 25mm×200mm, peel off the peeled PET film (separation film) with a thickness of 38μm on one side of the adhesive sheet, and reattach the thickness of 50μm on one side for corona treatment The PET film, the adhesive surface (measurement surface) is attached to the test board, with a 2kg rubber roller (width: about 50mm) back and forth once and placed in an environment of 23 ℃, 50% humidity for 24 hours to obtain a test piece. As the test board, a glass plate was used.

For the test piece, according to JIS Z0237, the adhesive force before the irradiation of the active energy ray and the adhesive force after the irradiation of the active energy ray were pulled by the peeling speed of 300 mm/min and the adhesion force (N/25 mm) to the glass plate in the direction of 180° The test is carried out. In addition, as an active energy ray, a metal halogen lamp (100 mW/cm ² ) is used, and ultraviolet rays are irradiated with a cumulative light amount of 1000 mJ/cm ² . The results are shown in Table 2.

[5] Total light transmittance

Cut the adhesive sheet obtained in the above [1] into a size of 30 mm × 30 mm, peel off the peeled PET film (separator film) with a thickness of 38 μm on one side of the peeled PET film existing on both sides of the adhesive sheet, so as to stick to the glass plate And use it as a sample for measurement. For the sample for measurement, the total light transmittance (%) was measured using a haze meter (HR-100 type) manufactured by Murakami Color Technology Research Institute. The results are shown in Table 2.

[6] Foam peeling resistance

A 100mm×100mm optical PET film (COSMOSHINE (registered trademark) A4100, manufactured by Toyobo Co., Ltd.) is easily bonded to a polycarbonate plate (IUPILON (registered trademark) sheet MR-58 with a thickness of 1 mm, Mitsubishi Gas Chemical Co., Ltd. Manufacture) After laminating with the photoreactive transparent adhesive sheet obtained in [2] above, defoaming treatment is carried out in an autoclave (trade name: TAC-200, manufactured by SAKURA Seiki Co., Ltd.) at 40°C and 0.5 MPa for 10 minutes. Furthermore, a metal halogen lamp (100 mW/cm ² ) was used to irradiate ultraviolet rays with a cumulative light amount of 1000 mJ/cm ² , and this was used as a sample for measurement. Let it stand for 72 hours under the conditions of 85°C and 85% humidity to visually evaluate the appearance defects of foaming or peeling at the interface of the adhesive layer.

The evaluation of the resistance to foaming peeling was performed according to the following criteria. The results are shown in Table 2.

○: No foam

△: Foam with diameter less than 1mm

×: Foam with a diameter of 1mm or more

From the results in Table 2, it can be confirmed that the photo-reactive transparent adhesive sheets of Examples 1 to 7 are multifunctional (meth)acrylic resins, having a molecular weight in the specified range, and a carbon-carbon double bond equivalent multifunctional (a Base) acrylate oligomer, so transparency, adhesiveness, and foam resistance at the time of fixing of transparent resin plate are excellent.

In addition, since the photoreactive transparent adhesive sheets of Examples 1 to 5 set the content of (meth)acrylic resin to 80% by mass to 90% by mass, compared to setting the content of (meth)acrylic resin 96% by mass of the photo-reactive transparent adhesive sheet of Example 6 shows that the foam peeling resistance of Examples 1 to 5 is more excellent. In addition, the light-reactive transparent adhesive sheets of Examples 1 to 5 set the content of (meth)acrylic resin to 80% by mass to 90% by mass, as compared to setting the content of (meth)acrylic resin For the photo-reactive transparent adhesive sheet of Example 7 of 65% by mass, it can be seen that the adhesion of the Examples 1 to 5 before and after ultraviolet irradiation is higher.

In addition, the photo-reactive transparent adhesive sheets of Examples 1 to 5 set the content of the multifunctional (meth)acrylate oligomer to 10% by mass to 20% by mass, compared to the multifunctional (meth) ) The photoreactive transparent adhesive sheet of Example 6 in which the content of the acrylate oligomer is set to 4% by mass shows that the foam peeling resistance of Examples 1 to 5 is more excellent. In addition, the photo-reactive transparent adhesive sheets of Examples 1 to 5 set the content of the multifunctional (meth)acrylate oligomer to 10% by mass to 20% by mass, compared to the multifunctional (meth) ) The photoreactive transparent adhesive sheet of Example 7 with the content of acrylate oligomer set to 35% by mass and In other words, it can be seen that the adhesion of the examples 1 to 5 before and after ultraviolet irradiation is higher.

On the other hand, in the photoreactive transparent adhesive sheet of Comparative Example 1, since the molecular weight of the multifunctional (meth)acrylate oligomer is smaller than the specified range, it can be confirmed that the foaming resistance is poor.

Moreover, in the photoreactive transparent adhesive sheet of Comparative Example 2, since the molecular weight of the multifunctional (meth)acrylate oligomer is larger than the specified range, it can be confirmed that the foaming resistance is poor and the total light transmittance is low .

In addition, in the photoreactive transparent adhesive sheet of Comparative Example 3, since the carbon-carbon double bond equivalent of the multifunctional (meth)acrylate oligomer is larger than the specified range, it can be confirmed that the foaming resistance is poor.

In addition, in the photoreactive transparent adhesive sheet of Comparative Example 4, since the acid value is larger than the specified range, it can be confirmed that the rate of increase in the resistance value is high, and corrosion of the conductive film is not suppressed.

[Industry availability]

The composition for a photoreactive transparent adhesive sheet of the present invention is a multifunctional (meth)acrylate oligomer containing a (meth)acrylic resin and having a specific molecular weight and a carbon-carbon double bond equivalent, so this composition is used The light-reactive transparent adhesive sheet produced is excellent in transparency, adhesion, metal corrosion prevention of transparent conductive film, and foaming resistance during the fixing of transparent resin board, and can be widely used in the construction of touch panels or The components of the image display device are bonded together.

Claims (9)

A composition for a photoreactive transparent adhesive sheet, which is characterized by comprising (A) (meth)acrylic resin, and (B) a weight average molecular weight of 700 to 10,000 and a carbon-carbon double bond equivalent of 300 g/mol or less Functional (meth)acrylate oligomer, acid value is 0mgKOH/g~5mgKOH/g. The composition for a photoreactive transparent adhesive sheet according to claim 1, wherein the content of the (A) (meth)acrylic resin is 70% by mass to 95% by mass, and the (B) multifunctional (meth)acrylic acid The content of the ester oligomer is 5% by mass to 30% by mass, relative to 100 parts by mass of the total amount of the (A) (meth)acrylic resin and the (B) multifunctional (meth)acrylate oligomer , Containing 0.2 parts by mass to 5 parts by mass of (C) photopolymerization initiator. The composition for a light-reactive transparent adhesive sheet according to claim 1 or 2, wherein the (B) multifunctional (meth)acrylate oligomer is a polyester acrylate oligomer. The composition for a light-reactive transparent adhesive sheet according to claim 1 or 2, wherein the (A) (meth)acrylic resin contains 5 mol% to 10 mol% of a structure derived from a hydroxyl-containing (meth)acrylic monomer unit. A photo-reactive transparent adhesive sheet characterized by the composition for a photo-reactive transparent adhesive sheet of any one of claims 1 to 4. A photo-reactive transparent adhesive sheet for fixing a transparent resin board, the characteristic of which is formed by the photo-reactive transparent adhesive sheet of claim 5. A photo-reactive transparent adhesive sheet for fixing a transparent conductive film, which is characterized by the photo-reactive transparent adhesive sheet of claim 5. A touch panel characterized by having the hardened product of the light-reactive transparent adhesive sheet of any one of claims 5 to 7. An image display device characterized by having the cured product of the photoreactive transparent adhesive sheet of any one of claims 5 to 7.