TWI616502B - Adhesive composition, adhesive sheet and laminate - Google Patents

Abstract

The adhesive composition of the present invention contains at least one of (A) a monofunctional (meth) acrylic monomer and a prepolymer obtained by polymerizing the monofunctional (meth) acrylic monomer, and (B) Di (meth) acrylates having a specific bisphenol A structure, and (C) polyfunctional (meth) acrylates other than (B); and in (A), (B), and ( The total mass of C) includes 72.5 to 97% by mass of the above (A), 3 to 25% by mass of the above (B), and 0 to 2.5% by mass of the (C). The adhesive composition can provide an adhesive sheet and a laminated body that exhibit good adhesion to transparent plastics, have excellent transparency even under high temperature and high humidity, and have no bubble generation and peeling durability.

Description

Adhesive composition, adhesive sheet and laminate

The invention relates to an acrylic adhesive composition and its application. More specifically, the present invention relates to an acrylic adhesive composition suitable for bonding to a transparent plastic member, an adhesive sheet and a laminated body using the adhesive composition.

In recent years, an input device in which a touch panel is combined with a display device such as a liquid crystal display has been widely used in various fields. In the manufacture of a touch panel, an adhesive sheet is used for bonding a glass substrate or a plastic substrate with a transparent conductive film. The adhesive sheet used for these applications requires excellent reliability such as transparency, or properties that do not cause foaming or peeling under high temperature and high humidity environments. In particular, the amount of outgassing from plastic components such as plastic substrates or plastic films is more than that of glass substrates. Therefore, foaming or peeling is likely to occur at the close interface between the adhesive sheet and the plastic member, and the industry requires improvement.

Patent Document 1 proposes an acrylic adhesive composition which is excellent in adhesion between a transparent conductive film and a glass substrate, etc., even under a high temperature and high humidity environment, and is not between the adhesive layer and the glass substrate. A metal chelate compound is prepared for the purpose of generating foam or peeling.

Patent Document 2 proposes an acrylic adhesive sheet which exhibits good adhesion to transparent optical plastics such as polycarbonate and optical members such as glass, and suppresses whitening and generation of bubbles in a high-temperature and high-humidity environment. And the purpose of peeling Polymer, low molecular weight polymer, styrenic polymer, etc. as components.

Patent Document 3 proposes an adhesive composition containing 100 parts by mass of a methacrylic copolymer (A), 0.01 to 10 parts by mass of a di (meth) acrylate (B) having a bisphenol structure, and having 1 to 30 parts by mass of a polyfunctional acrylic compound (C) having 3 to 10 (meth) acrylfluorenyl groups, 0.1 to 10 parts by mass of a hydrogen abstraction type photopolymerization initiator, and an isocyanate having 2 or more isocyanate groups in the molecule 0.01 to 10 parts by mass of a crosslinking agent and 0.01 to 3 parts by mass of a silane compound having an organic functional group that reacts with a carboxyl group; and the compounding amount of the di (meth) acrylate (B) and the polyfunctional acrylic compound (C The total amount of the blending amount is 3 to 40 parts by mass, and the blending amount of the polyfunctional acrylic compound (C) is more than the blending amount of the di (meth) acrylate (B).

Patent Document 4 proposes a low-polarity surface adhesive, which is a polymer containing 97% by mass or more of a monomer component containing no active hydrogen (meth) acrylic acid alkyl ester using active energy rays ( A) The composition of the active energy ray-curable compound (B) and the photopolymerization initiator (C) is cured. Moreover, in Example 2, there is described an adhesive which is based on 100 parts by mass of a homopolymer of 2-ethylhexyl acrylate as a monomer component, and contains ethylene oxide-modified bisphenol A diacrylate 2 Part by mass and 0.6 part by mass of a photopolymerization initiator (see Example 2).

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2012-136660

[Patent Document 2] Japanese Patent Laid-Open No. 2011-246613

[Patent Document 3] International Publication No. 2010/092988

[Patent Document 4] Japanese Patent Laid-Open No. 2010-100760

However, the present inventors et al. Described the adhesive combinations described in Patent Documents 1 to 4. Various performance evaluations were performed on the materials, and the results showed that the transparency of the adhesive sheet was poor.

The adhesive composition disclosed in Patent Documents 1 and 2 is a so-called two-component solution obtained by dissolving a (meth) acrylate polymer in an organic solvent and preparing a cross-linking agent immediately before molding. A solvent-based adhesive composition. That is, the adhesive composition is a type in which the solvent is volatilized by heating and the post-crosslinking agent causes a crosslinking reaction to crosslink the (meth) acrylate polymer, thereby exhibiting the properties of the adhesive. Adhesive. The solvent-based adhesive requires a step of formulating a post-crosslinking agent immediately before being applied to the release film, and requires a production time of a curing time of generally 3 days to about 1 week for the cross-linking reaction.

Furthermore, it is clear from research by the present inventors that in Patent Document 3, the adhesive composition is yellowed under high temperature and high humidity.

In addition, it is clear from research by the present inventors that in Patent Document 4, durability under high temperature and high humidity is poor.

An object of the present invention is to provide an adhesive composition capable of forming an adhesive layer that does not cause whitening or yellowing even in a high-temperature and high-humidity environment and has excellent transparency; it is difficult to generate between the adhesive layer and transparent plastic. An adhesive sheet and a laminate which are foamed or peeled and have excellent durability and excellent productivity.

That is, the present invention has the following aspects.

[1] An adhesive composition comprising (A) a monofunctional (meth) acrylic monomer and a prepolymer obtained by polymerizing a monofunctional (meth) acrylic monomer At least one of (B) a di (meth) acrylate having a bisphenol A structure represented by the following general formula (1), and (C) a polyfunctional (meth) acrylate other than the above (B) ; And the total mass of (A), (B), and (C) above includes 72.5 to 97% by mass of (A), 3 to 25% by mass of (B), and 0 to 2.5 of (C) quality%;

(In the general formula (1), R ^a represents a hydrogen atom or a methyl group, R ^b represents an alkylene group having 2 to 4 carbon atoms; m and n each independently represent an integer of 1 to 15; m + n is 2 to 30; Integer).

[2] The adhesive composition according to [1], which contains a polymerization initiator (D) in an amount of 0.05 to 3.5% by mass based on the total mass of the (A), (B), and (C).

[3] The adhesive composition according to [1] or [2], which does not contain an isocyanate group-containing compound having two or more isocyanate groups in the molecule.

[4] An adhesive sheet having an adhesive layer containing a cured product of the adhesive composition according to any one of [1] to [3].

[5] An adhesive sheet with a release sheet, characterized in that a release sheet is provided on one surface or both surface areas of the adhesive layer of the adhesive sheet according to [4].

[6] A laminated body characterized in that the adhesive layer of the adhesive sheet according to [4] is adhered to a transparent plastic.

[7] The laminated body according to [6], wherein the transparent plastic is polycarbonate.

The adhesive composition and the adhesive sheet of the present invention have high resistance to moist heat whitening and moisture heat yellowing, and excellent transparency. In addition, since the adhesiveness is good, foaming or peeling does not occur, and durability is excellent. Furthermore, since the cross-linking reaction proceeds by radical polymerization, no aging time is required, and productivity is high.

1‧‧‧ double-sided adhesive sheet with release sheet

2‧‧‧ laminated body

11‧‧‧ Adhesive layer

12a, 12b ‧‧‧ peeling sheet

21‧‧‧Transparent plastic

22‧‧‧Optical Components

FIG. 1 is a cross section showing an embodiment of an adhesive sheet with a release sheet of the present invention Illustration.

Fig. 2 is a cross-sectional view showing an embodiment of the laminated body of the present invention.

The present invention will be specifically described below. In addition, in this specification, a numerical range indicated by "~" means a range including numerical values described before and after "~" as a lower limit value and an upper limit value. In the present specification, the "monofunctional (meth) acrylic monomer" means a polymerizable functional group having an unsaturated double bond such as a (meth) acrylfluorenyl group or a vinyl group in the molecule. monomer. The "(meth) acrylate" means one or both of an acrylate and a methacrylate. The "multifunctional (meth) acrylate" refers to a (meth) acrylate having two or more (meth) acrylfluorenyl groups in a molecule. The "(meth) acrylfluorenyl group" means any one or both of an acrylfluorenyl group and a methacrylfluorenyl group.

The adhesive composition of the present invention is characterized in that it contains at least one of (A) a monofunctional (meth) acrylic monomer and a prepolymer obtained by polymerizing the monofunctional (meth) acrylic monomer. (B) a di (meth) acrylate having a bisphenol A structure represented by the following general formula (1), and (C) a polyfunctional (meth) acrylate other than the above (B); and The total masses of (A), (B), and (C) above include 72.5 to 97% by mass of (A), 3 to 25% by mass of (B), and 0 to 2.5% by mass of (C). .

(In the general formula (1), R ^a represents a hydrogen atom or a methyl group, and R ^b represents an alkylene group having 2 to 4 carbon atoms. M and n each independently represent an integer of 1 to 15 and m + n is 2 to 30 Integer).

Hereinafter, the constituent components of the adhesive composition of the present invention will be described in detail.

(A) a monofunctional (meth) acrylic monomer and a prepolymer obtained by polymerizing a monofunctional (meth) acrylic monomer (hereinafter, both are collectively referred to as "(A) component". (The prepolymer obtained by polymerizing a monofunctional (meth) acrylic monomer is also referred to as "prepolymer (X)")

In the present invention, as the component (A), a monofunctional (meth) acrylic monomer and a prepolymer (X) can be used individually. It is also possible to use a mixture of the two.

(Monofunctional (meth) acrylic monomer)

In the present invention, as the monofunctional (meth) acrylic monomer, an alkyl (meth) acrylate (A1), a polar-containing monofunctional (meth) acrylic monomer (A2), and the like can be used.

(A1. Alkyl (meth) acrylate)

The alkyl (meth) acrylate (A1) is a monofunctional (meth) acrylate having an alkyl group. The alkyl group may be linear or branched. The carbon number of the alkyl group is preferably from 1 to 14, more preferably from 2 to 12, and even more preferably from 4 to 10.

Specific examples of the alkyl (meth) acrylate (A1) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and n- (meth) acrylate Butyl ester, second butyl (meth) acrylate, third butyl (meth) acrylate, isobutyl (meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate ( Isopentyl (meth) acrylate), hexyl (meth) acrylate, heptyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , N-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, and the like. These can be used alone or in combination.

(A2. Monofunctional (meth) acrylic monomer containing polar group)

In the present invention, as the monofunctional (meth) acrylic monomer, a monofunctional (meth) acrylic monomer containing a carboxyl group, a monofunctional (meth) acrylic monomer containing a hydroxyl group, and a fluorene-containing monomer may also be used. Monofunctional (meth) acrylic monomer based on amine. These can be used alone or Two or more types can be used together. Furthermore, a polar-group-containing monofunctional (meth) acrylic monomer (A2) and an alkyl (meth) acrylate (A1) may be used in combination. When the (meth) acrylic acid alkyl ester (A1) and the polar group-containing monofunctional (meth) acrylic monomer (A2) are used together, the polar group-containing monofunctional (meth) acrylic monomer ( The content of A2) is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, and even more preferably 0 to 5% by mass in the total amount of monofunctional (meth) acrylate. By setting it as such content, it can provide excellent adhesive property without affecting transparency.

Examples of the carboxyl group-containing monofunctional (meth) acrylic monomer include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, and carboxypentyl (meth) acrylate. These can be used alone or in combination. use. Among these, acrylic acid and methacrylic acid are preferred from the viewpoint of adhesion, and acrylic acid is particularly preferred.

Examples of the hydroxyl-containing monofunctional (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate. Ester, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, (meth) 12-hydroxylauryl acrylate and other hydroxyalkyl (meth) acrylates; hydroxyethyl (meth) acrylamide, (4-hydroxymethylcyclohexyl) methyl acrylate, N-hydroxymethyl (methyl) Acrylamide, N-hydroxy (meth) acrylamide, and the like can be used alone or in combination. Among these, hydroxyalkyl (meth) acrylate is preferable from a viewpoint of adhesiveness.

Examples of the monofunctional (meth) acrylic monomer containing amidino group include N, N-dimethylaminoethyl acrylate, N, N-dimethylacrylamido, N, N-diethyl Acrylamide, N-acrylamide Porphyrin, etc.

(X. prepolymer)

In the present invention, the (A) component may be polymerized in advance as a monofunctional (meth) acrylic monomer and used as a prepolymer. Prepolymers can be used in (meth) acrylic acid alkyl ester (A1), or (meth) acrylic acid alkyl ester (A1) and polar functional monofunctional (meth) acrylic acid A photopolymerization initiator (D ') is added to the mixture of the monomers (A2), and it is obtained by light irradiation. In this case, a chain transfer agent may be added as needed. As a polymerization initiator (D ') for prepolymerizing a monofunctional (meth) acrylic monomer, the same as the following polymerization initiator (D) can be used. The amount of the polymerization initiator (D ') used for prepolymerization of the monofunctional (meth) acrylic monomer is preferably 0.001 to 1 mass relative to 100 parts by mass of the monofunctional (meth) acrylic monomer. Parts, more preferably 0.005 to 0.5 parts by mass. If it is within the above range, a prepolymer having a desired viscosity can be obtained.

In the adhesive composition of the present invention, the component (A) is the total mass of the component (A), the following di (meth) acrylate (B), and the following polyfunctional (meth) acrylate (C) The content is 72.5 to 97% by mass, and preferably 78 to 96% by mass. When content of (A) component exists in the said range, it will become an adhesive sheet which is soft and has favorable adhesive characteristics and adhesive durability.

(B. Di (meth) acrylate)

In the present invention, as the di (meth) acrylate, a di (meth) acrylate having a bisphenol A structure represented by the following general formula (1) (hereinafter referred to as "di (meth) acrylic acid") is used. Esters (B) "). By heating or irradiating active energy rays such as ultraviolet rays to the adhesive composition of the present invention, cross-linking caused by radical polymerization occurs between the component (A) and the di (meth) acrylate (B). The result is a three-dimensional polymer structure.

In the general formula (1), R ^a represents a hydrogen atom or a methyl group, and R ^b represents an alkylene group having 2 to 4 carbon atoms. m and n each independently represent an integer of 1-15, and m + n is an integer of 2-30. It is preferably m: n = 1: 1: 1.

Since the bisphenol structure of the di (meth) acrylate (B) represented by the general formula (1) is similar to the structure of polycarbonate, the adhesion is improved especially when the adherend is polycarbonate.

Specific examples of the di (meth) acrylate (B) include, for example, ethylene oxide-modified bisphenol A dimethacrylate (the following formula (1-1)) and propylene oxide-modified bis Phenol A diacrylate (the following formula (1-2)) and the like. These can be used alone or in combination.

In formula (1-1), m and n each independently represent an integer of 1 to 15, and m + n = 30.

In formula (1-2), m and n each independently represent an integer of 1 to 5, and m + n = 10.

In the adhesive composition of the present invention, the di (meth) acrylate (B) is added to the component (A), the di (meth) acrylate (B), and the following multifunctional (meth) acrylate (C ) Contains 3 to 25% by mass, and more preferably 4 to 20% by mass. If it is at least the above lower limit value, it is difficult to cause the interface between the adhesive and the adherend to swell or peel due to obtaining a moderate cohesive force, and it is difficult to cause whitening in a high-temperature and high-humidity environment. Therefore, transparency is easily obtained. When content is below the said upper limit, an adhesive composition will be soft and adhesiveness will also be favorable.

(C. Multifunctional (meth) acrylate)

The adhesive composition of the present invention may further contain a polyfunctional (meth) acrylate (C) other than the di (meth) acrylate (B).

Examples of the polyfunctional (meth) acrylate (C) include dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, bis (trimethylolpropane) tetraacrylate, and trimethylol Propane acrylate, dipentaerythritol triacrylate, and the like.

In the adhesive composition of the present invention, the polyfunctional (meth) acrylate (C) is added to the component (A), the di (meth) acrylate (B), and the polyfunctional (meth) acrylate (C). ) Contains 0 to 2.5% by mass, more preferably 0 to 2% by mass. In the polyfunctional (meth) acrylate (C), the content of the compound having three or more acrylate groups is in the component (A), the di (meth) acrylate (B), and the polyfunctional (formaldehyde). In the total mass of the acrylate) (C), 0 to 2% by mass is preferred, and 0 to 1% by mass is more preferred. By setting the content to be equal to or less than the above upper limit value, an adhesive composition capable of forming an adhesive sheet having excellent transparency can be obtained. Moreover, since the content of the polyfunctional (meth) acrylate (C) is lower than the content of the di (meth) acrylate (B), an adhesive sheet having excellent durability and transparency can be formed.

(D. Polymerization initiator)

As the polymerization initiator (D), at least one selected from the group consisting of a photopolymerization initiator (D1) and a thermal polymerization initiator (D2) can be used. The blending amount of the polymerization initiator (D) is preferably 0.1 relative to the total mass of the component (A), the di (meth) acrylate (B), and the polyfunctional (meth) acrylate (C). ~ 3.5 mass%, particularly preferably 0.1 to 3.0 mass%. When the blending amount is equal to or more than the above-mentioned lower limit value, the polymerization rate is increased, and the adhesion holding force is easily increased. If it is below the said upper limit, molecular weight and gel fraction are high, adhesive durability is improved, and yellowing is hard to occur, and transparency is easily improved.

As the photopolymerization initiator (D1), at least one selected from the group consisting of a cleavage type photopolymerization initiator and a hydrogen abstraction type photopolymerization initiator can be used. Examples of the cracking-type photopolymerization initiator include: Benzoin such as benzoin, benzoin isobutyl ether; dimethyl benzophenone ketal, 2,2-dimethoxyphenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl Acetophenones such as phenyl-1-phenylpropane-1-one; bis (2,4,6-trimethylbenzylidene) phenylphosphine oxide, 2,4,6-trimethylbenzidine Fluorenyl phosphine oxides such as diphenylphosphine oxide and the like.

Examples of the hydrogen abstraction-type photopolymerization initiator include benzophenone, methylbenzophenone, trimethylbenzophenone, o-benzophenanthranilic acid, methyl o-benzophenanthrene benzoate, 4-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4-fluorobenzophenone, 4,4'-difluorobenzophenone, tetrakis (third butylcarbonyl peroxide) Benzophenones such as benzophenone, [4- (methylphenylthio) phenyl] phenylmethanone; 9-oxysulfur , 2,4-diethyl 9-oxysulfur , 2-chloro9-oxysulfur 9-oxysulfur Class, etc.

The photopolymerization initiator (D1) may be used alone or in combination of two or more kinds.

As the thermal polymerization initiator (D2), at least one selected from the group consisting of an organic peroxide-based polymerization initiator and an azo-based polymerization initiator can be used.

Examples of the organic peroxide-based polymerization initiator include tert-hexyl peroxyneododecanoate, tert-butyl peroxydodecanoate, tert-butyl peroxyheptanoate, peroxy Lauryl oxide, bis (4-third-butylcyclohexyl) dicarbonate, 2-ethylhexanoic acid 1,1,3,3-tetramethylbutyl peroxide, 2-hexanoic acid Trihexyl ester, 2-butylhexanoic acid tert-butyl ester, and the like.

Examples of the azo-based polymerization initiator include 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2, 4-dimethylvaleronitrile), 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (isobutyronitrile) Butyric acid) dimethyl ester, 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride Salt, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate, 2,2'-azobis [2- (2-imidazoline-2) -Yl) propane], 2,2'-azobis (2-fluorenylpropane) dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropane脒] n hydrate.

The thermal polymerization initiator (D2) may be used alone or in combination of two or more kinds. When mixing From the viewpoint of storage stability, the 10-hour half-life temperature of the thermal polymerization initiator is preferably 40 ° C or higher. From the viewpoint of reactivity, the half-life temperature for one minute of the thermal polymerization initiator is preferably 100 ° C to 130 ° C. Examples of such thermal polymerization initiators include tertiary hexyl peroxydodecanoate, tertiary butyl peroxydodecanoate, tertiary butyl peroxyheptanoate, 2, 2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2-methylbutyronitrile), 2 , 2'-azobis (isobutyric acid) dimethyl ester, 4,4'-azobis (4-cyanovaleric acid).

(additive)

In the adhesive composition of the present invention, for example, a light stabilizer such as an adhesion-imparting agent, a silane coupling agent, an ultraviolet absorber, a hindered amine compound, an antioxidant, an anti-metal corrosion agent, Anti-rust agent, anti-static agent and other additives.

Examples of the adhesion-imparting agent include rosin-based resins, terpene-based resins, terpene-phenol-based resins, lavender-indene-based resins, styrene-based resins, xylene-based resins, phenol-based resins, and petroleum resins. .

Examples of the silane coupling agent include vinyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, p-styryltrimethoxysilane, and 3-methacrylic acid. Oxypropyltrimethoxysilane, 3-propenyloxypropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-mercapto Propylmethyldimethoxysilane and the like.

Examples of the ultraviolet absorber include benzotriazole-based compounds and benzophenone-based compounds.

Examples of the antioxidant include a phenol-based antioxidant, an amine-based antioxidant, a lactone-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant. These antioxidants may be used individually by 1 type, and may use 2 or more types together.

As an anti-metal corrosion agent, in terms of the compatibility or effect of the adhesive, It is preferably a benzotriazole-based resin.

The acrylic adhesive composition of the present invention is preferably free of a non-radical reactive crosslinking agent. The non-radical reactive cross-linking agent referred to here is a well-known cross-linking agent usually used in a so-called two-component solvent-based adhesive composition, such as an epoxy compound or an isocyanate compound. Examples of the isocyanate compound include an isocyanate group-containing compound having two or more isocyanate groups in the molecule. Because it does not contain a non-radical reactive cross-linking agent, it does not require a curing time for the cross-linking reaction in the production of the adhesive sheet, and has high productivity. In addition, the occurrence of yellowing and the like can be more effectively suppressed.

In addition, the adhesive composition of the present invention may also be an adhesive composition for transparent plastic bonding and containing a carbon number of 4 to 14 as a constituent component of the (meth) acrylate polymer. Alkyl (meth) acrylate, 3 to 20% by weight based on monomer units, di (meth) acrylate represented by the following formula (1), and polymerization initiator, and does not contain trifunctional The above polyfunctional (meth) acrylates. A (meth) acrylate having an alkyl group having 4 to 14 carbons corresponds to the above-mentioned (A) component, and a di (meth) acrylate corresponds to the above-mentioned di (meth) acrylate (B).

In the formula (1), R ^a represents hydrogen or a methyl group, and R ^b represents an alkyl group having 2 to 4 carbon atoms. m and n each represent an integer, and the total of m and n is 2 to 30.

The adhesive composition of the present invention can be irradiated with at least one of active energy rays and heat to form an adhesive hardened material. The gel fraction after hardening is preferably 65% or more, and more preferably 70% or more. If the gel fraction is above the lower limit, it will be difficult to achieve a high gel fraction. Foaming, bulging, peeling, etc. occur at high temperature and humidity, and it is easy to improve durability. The gel fraction is determined from the weight change before and after solvent extraction.

<Adhesive sheet>

The adhesive sheet of the present invention has an adhesive layer containing a cured product of the above-mentioned adhesive composition. The adhesive sheet of the present invention may be a single-sided adhesive sheet or a double-sided adhesive sheet.

Examples of the single-sided adhesive sheet include a multilayer sheet in which an adhesive layer is laminated on a support such as a film. The peeling sheet can also be laminated on the adhesive layer of the multilayer sheet. Alternatively, another layer may be provided between the support and the adhesive layer.

As the double-sided adhesive sheet, a single-layer sheet including an adhesive layer; a multilayer sheet having a plurality of adhesive layers laminated; a multilayer sheet having an adhesive layer and an adhesive layer other than the adhesive layer laminated A multilayer sheet having an adhesive layer on two areas of the support; a multilayer sheet having an adhesive layer on a single area of the support; and a multilayer sheet having an adhesive layer other than the adhesive layer on the other area; Such as a single-layer sheet or a multi-layer sheet, a single-layer sheet or a multi-layer sheet with a release sheet and a multi-layer sheet.

<Adhesive sheet with release sheet>

The adhesive sheet with a release sheet of the present invention has a structure in which a release sheet is formed on one surface or both surfaces of the adhesive layer of the adhesive sheet. The structure of the double-sided adhesive sheet with a peeling sheet of this invention is demonstrated. Fig. 1 shows a double-sided adhesive sheet with a release sheet. As shown in FIG. 1, the double-sided adhesive sheet 1 with a release sheet includes an adhesive layer 11 and release sheets 12 a and 12 b. The above-mentioned double-sided adhesive sheet 1 with a release sheet is on both sides of a release sheet with a release sheet 12 layered on at least one side, preferably two areas, of the release sheet 12 in a manner that does not expose the adhesive layer 11 before use. The state of the adhesive sheet.

(Peeling Sheet)

The release sheets 12a and 12b are sheets having releasability on at least one side, and examples thereof include a release laminate having a substrate for a release sheet and a release agent layer provided on one side of the substrate for the release sheet. Sheet, or polyolefin such as polyethylene film or polypropylene film as low-polarity substrate membrane.

As a base material for a release sheet of a release laminated sheet, paper or a polymer film is used. As the release agent constituting the release agent layer, for example, a general-purpose addition-type or condensation-type silicone release agent or a compound containing a long-chain alkyl group can be used. It is particularly preferable to use a highly reactive addition-molded silicone release agent.

Specific examples of the polysiloxane-based release agent include BY24-4527 and SD-7220 manufactured by Dow Corning Toray Silicone, and KS-3600, KS-774, and X62-2600 manufactured by Shin-Etsu Chemical Industry Co., Ltd. In addition, it is preferable that the polysiloxane-based release agent contains polysilicon, which is an organic silicon compound having SiO ₂ units and (CH ₃ ) ₃ SiO _1/2 units or CH ₂ = CH (CH ₃ ) SiO _1/2 units. Oxygen resin. Specific examples of the silicone resin include BY24-843, SD-7292, SHR-1404, etc. manufactured by Dow Corning Toray Silicone, or KS-3800, X92-183, etc. manufactured by Shin-Etsu Chemical Industry Co., Ltd.

(Manufacturing method of double-sided adhesive sheet with release sheet)

As a method for manufacturing an adhesive sheet, an adhesive composition is coated on the release sheet 12b and the release sheet 12a is overlapped, and thereafter the adhesive composition is hardened by radical polymerization using heat or active energy ray irradiation. ， Forming an adhesive layer 11. Thus, a double-sided adhesive sheet 10 with a release sheet can be obtained.

The adhesive layer 11 obtained by hardening the adhesive composition of the present invention need not be cured. Therefore, the double-sided adhesive sheet 1 with a release sheet of the present invention can be manufactured with good productivity.

The application of the adhesive composition of the present invention can be performed using a known coating device. Examples of the coating device include a blade coater, an air knife coater, a roll coater, a rod coater, a gravure coater, a microgravure coater, a rod-type blade coater, Die lip coater, die coater, curtain coater, etc.

The thickness of the adhesive layer 11 is preferably adjusted according to the object to be bonded or the required buffering force, etc., preferably 0.01 to 1 mm, and more preferably 0.02 to 0.3 mm.

Examples of the active energy rays include ultraviolet rays, electron beams, visible rays, X-rays, and ion beams, and they can be appropriately selected according to the polymerization initiator (D) contained in the adhesive layer 11. Among them, in terms of versatility, ultraviolet rays or electron beams are preferable, and ultraviolet rays of 250 to 400 nm are more preferable.

Regarding the ultraviolet irradiation conditions, when measuring with an ultraviolet illuminance meter having a spectral sensitivity around 365 nm, it is preferable that the radiation illuminance is 0.1 mW / cm ² or more and the light amount is 500 mJ / cm ² or more. If it is more than the said lower limit, a gel fraction is high and the required adhesion durability is obtained.

As a light source, an ultraviolet fluorescent lamp such as a chemical lamp or a black light lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, an ultra-high-pressure mercury lamp, a mercury xenon lamp, a metal halide lamp, an LED (Light Emitting Diode) lamp, and a carbon arc can be used Lamps, xenon arc lamps, etc. As the electron beam, for example, a Cockcroft Walt type, a Van de Graaff type, a resonant transformer type, an insulated core transformer type, a linear type, and a high frequency and high voltage type can be used. Electron beams emitted by various electron beam accelerators such as high-frequency and high-frequency types.

In the case of heating, a normal heating mechanism can be used. Examples include hot air dryers, electric heaters, and IR (Infrared Ray) heaters. The heating temperature is preferably 80 to 150 ° C. and the heating time is 5 to 20 minutes.

<Layered body>

An embodiment of the laminated body of the present invention will be described. The laminated body of the present invention has a structure in which the above-mentioned adhesive sheet is adhered to a transparent plastic. For example, the laminated body 2 of the present embodiment is obtained by laminating a transparent plastic 21 and an optical member 22 with an adhesive layer 11 of a double-sided adhesive sheet 1 (see FIG. 2).

The transparent plastic 21 is an acrylic resin, a polycarbonate resin, a cyclic olefin resin, a multilayer resin in which an acrylic resin is laminated on the surface of the polycarbonate resin, a polyethylene terephthalate resin, a polystyrene resin, and MMA. (Methyl methacrylate, methyl methacrylate) -styrene copolymer resin (MS (methylmethacrylate-styrene) resin), etc. Plate-like substrate or film. Among them, the transparent plastic 21 is preferably made of polycarbonate resin.

Examples of the optical member 22 include a transparent conductive film, a polarizing plate, and a wavelength plate.

[Example]

Next, the present invention will be described in more detail by examples, but the present invention is not limited to these examples. In addition, the production, various test methods, and evaluation methods of the bonding test piece used in the Example and the comparative example are as follows.

<Manufacture of Prepolymer (X)> (Production Example X1)

100 parts by mass of 2-ethylhexyl acrylate (2EHA, 2 Ethyl Hexyl Acrylate) as an alkyl (meth) acrylate (A1) was added to a reaction vessel equipped with a nitrogen introduction tube and a stirring device as a prepolymer. 0.02 parts by mass of 2-hydroxy-2-methyl-1-phenyl-propane-1-one (D1) as a photopolymerization initiator (D ') for production. After replacing the air in the container with nitrogen, it was irradiated with ultraviolet rays with an output peak at 365 nm while stirring, and the viscosity was 1,000 mPa. Prepolymer X1 of sec.

(Manufacture example X2)

85 parts of 2-ethylhexyl acrylate (2EHA) was used as the alkyl (meth) acrylate (A1), and acrylic acid was used as the monofunctional (meth) acrylic monomer (A2) containing polar groups. A prepolymer X2 was produced in the same manner as in Production Example 1 except for 5 parts by mass and 10 parts by mass of 4-hydroxybutyl acrylate.

(Production Example X3)

As the (meth) acrylic acid alkyl ester (A1), 80 parts by mass of 2-ethylhexyl acrylate (2EHA) was used, and as the polar group-containing monofunctional (meth) acrylic monomer (A2), A prepolymer X3 was produced in the same manner as in Production Example 1 except for 20 parts by mass of 4-hydroxybutyl acrylate.

(Production Example X4)

95 mass parts of n-butyl acrylate was used as the (meth) acrylic acid alkyl ester (A1), and n-butyl methacrylate was used as the monofunctional (meth) acrylic monomer (A2) containing a polar group. Except for 5 parts by mass, a prepolymer X4 was produced in the same manner as in Production Example 1.

The viscosity of the obtained prepolymers X1 to X4 was measured with a rotary viscometer at 25 ° C, and the obtained results are shown in Table 1.

[Example 1]

90 parts by mass of the prepolymer (X1), 5 parts by mass of 2-ethylhexyl acrylate (2EHA) as alkyl (meth) acrylate (A1), and 2 parts of di (meth) acrylate (B) 5 parts by mass of ethylene oxide-modified bisphenol A dimethacrylate (EO (2) DMA) and 0.5 parts by mass of 1-hydroxy-cyclohexyl-phenyl-one as a polymerization initiator (D) were mixed To prepare an adhesive composition. The obtained adhesive composition was sandwiched between two peeled polyester films (MRV # 50 manufactured by Mitsubishi Resins Co., Ltd. and Teijin Dupont Films Co., Ltd.) so that the thickness of the cured adhesive sheet became 200 μm. The manufactured A50 # 50) was irradiated with ultraviolet rays from one side so that the cumulative light amount at 365 nm became 500 mJ / cm ² through a polyester film through a peeling treatment through a black light lamp to produce an adhesive sheet. The accumulated light amount is measured using a UV-integrated light amount meter UIT-150-A manufactured by USHIO Electric Co., Ltd. using a sensor UVD-C365.

[Example 2]

97 parts by mass of the prepolymer (X2) was prepared as a composition, and ethylene oxide-modified bisphenol A dimethacrylate (EO (30) DMA) 3 was used as the di (meth) acrylate (B). Except for mass parts, an adhesive composition was prepared in the same manner as in Example 1 to prepare an adhesive sheet.

[Example 3]

95 parts by mass of the prepolymer (X3) was prepared as a composition, and ethylene oxide-modified bisphenol A dimethacrylate (EO (30) DMA) as a di (meth) acrylate (B) 5 Except for mass parts, an adhesive composition was prepared in the same manner as in Example 1 to prepare an adhesive sheet.

[Example 4]

95 parts by mass of the prepolymer (X4) was prepared as a composition, and ethylene oxide-modified bisphenol A dimethacrylate (EO (30) DMA) as a di (meth) acrylate (B) was 5 Except for mass parts, an adhesive composition was prepared in the same manner as in Example 1 to prepare an adhesive sheet.

[Example 5]

90 mass parts of 2-ethylhexyl acrylate (2EHA) as alkyl (meth) acrylate (A1) and 5 mass of acrylic acid as monofunctional (meth) acrylic monomer (A2) containing polar group Parts, 5 parts by mass of ethylene oxide-modified bisphenol A dimethacrylate (EO (30) DMA) as di (meth) acrylate (B), and 1--1 as polymerization initiator (D) 3 parts by mass of hydroxy-cyclohexyl-phenyl-one were mixed to prepare an adhesive composition. In the same manner as in Example 1, an adhesive sheet was prepared from the obtained adhesive composition.

[Example 6]

The alkyl (meth) acrylate (A1) is 2-ethylhexyl acrylate (2EHA) 95 A pressure-sensitive adhesive composition was prepared in the same manner as in Example 5 except that the polar functional group-containing monofunctional (meth) acrylic monomer (A2) was not contained in parts by mass, and an adhesive sheet was produced.

[Example 7]

As the (meth) acrylic acid alkyl ester (A1), 80 parts by mass of n-butyl acrylate (BA) was used, and as the polar group-containing monofunctional (meth) acrylic monomer (A2), acrylic acid 4 was used. 5 parts by mass of hydroxybutyl ester (4HBA), and 15 parts by mass of ethylene oxide modified bisphenol A dimethacrylate (EO (30) DMA) was used as the di (meth) acrylate (B). Except for the above, an adhesive composition was prepared in the same manner as in Example 5 to produce an adhesive sheet.

[Example 8]

As the (meth) acrylic acid alkyl ester (A1), 80 parts by mass of n-butyl acrylate (BA) was used, and as the di (meth) acrylate (B), ethylene oxide-modified bisphenol A di Except for 20 parts by mass of methacrylate (EO (2) DMA) and containing no polar-containing monofunctional (meth) acrylic monomer (A2), an adhesive was prepared in the same manner as in Example 5. Agent composition to make an adhesive sheet.

[Example 9]

93 parts by mass of 2-ethylhexyl acrylate (2EHA) as alkyl (meth) acrylate (A1) and ethylene oxide-modified bisphenol A di (meth) acrylate (B) 7 parts by mass of methacrylate (EO (30) DMA) and 1 part by mass of third hexylperoxyneododecanoate as a polymerization initiator (D) were prepared to prepare an adhesive composition. The obtained adhesive composition was sandwiched between two peeled polyester films so that the thickness of the hardened adhesive sheet became 200 μm, and heated at 100 ° C. for 10 minutes with a hot air dryer to produce an adhesive. Sheet.

[Example 10]

As the alkyl (meth) acrylate (A1), 95 parts by mass of n-butyl acrylate (BA) was used, and as the di (meth) acrylate (B), ethylene oxide-modified bisphenol A di Except for 5 parts by mass of methacrylate (EO (2) DMA), it was prepared in the same manner as in Example 9. Adhesive composition to produce an adhesive sheet.

[Example 11]

The formulation composition was 90 parts by mass of the prepolymer (X2), 3 parts by mass of acrylic acid (AA) as the polar functional group-containing monofunctional (meth) acrylic monomer (A2), and di (meth) acrylic acid. Except for 7 parts by mass of ethylene oxide-modified bisphenol A dimethacrylate (EO (2) DMA) of the ester (B), an adhesive composition was prepared in the same manner as in Example 1 to prepare an adhesive. Sheet.

[Example 12]

As the (meth) acrylic acid alkyl ester (A1), 70 parts by mass of 2-ethylhexyl acrylate (2EHA) and 21 parts by mass of n-butyl acrylate (BA) were used as the monofunctional (methyl) group containing a polar group. ) The acrylic monomer (A2) is 3 parts by mass of acrylic acid (AA), 2 parts by mass of 4-hydroxybutyl acrylate (4HBA), and the di (meth) acrylate (B) is used as ethylene oxide. 3 parts by mass of modified bisphenol A dimethacrylate (EO (30) DMA), and 1 part by mass of dipentaerythritol hexaacrylate as the polyfunctional (meth) acrylate (C) is used. An adhesive composition was prepared in the same manner as in Example 5 to produce an adhesive sheet.

[Example 13]

The formulation composition was 89 parts by mass of the prepolymer (X1), 4 parts by mass of acrylic acid (AA) as the polar functional group-containing monofunctional (meth) acrylic monomer (A2), and 4-hydroxybutyl acrylate ( 4HBA) 1 part by mass, 5 parts by mass of ethylene oxide modified bisphenol A dimethacrylate (EO (30) DMA) as di (meth) acrylate (B) An adhesive composition was prepared in the same manner as in Example 1 except for 1 part by mass of phenol A dimethacrylate (EO (2) DMA), and an adhesive sheet was produced.

[Example 14]

A sample was prepared in the same manner as in Example 4 except that the addition amount of the polymerization initiator (D) was 4 parts by mass, and a test and evaluation were performed.

[Comparative Example 1]

Instead of using EO (2) DMA as the di (meth) acrylate (B), 5 parts by mass of dipentaerythritol hexaacrylate as the polyfunctional (meth) acrylate (C) was used. Samples were made in the same manner as in Example 1 and tested and evaluated.

[Comparative Example 2]

Instead of using EO (30) DMA as a di (meth) acrylate, and using 5 parts by mass of dipentaerythritol hexaacrylate as a polyfunctional (meth) acrylate (C), the same procedure as in Example 5 was used. Samples were made in the same manner and tested and evaluated.

[Comparative Example 3]

A sample was prepared in the same manner as in Example 6 except that the amount of EO (30) DMA added was 2 parts by mass, and the test and evaluation were performed.

[Comparative Example 4]

A sample was produced in the same manner as in Example 8 except that the amount of EO (2) DMA added was set to 30 parts by mass, and tested and evaluated.

[Comparative Example 5]

As the alkyl (meth) acrylate (A1), 90 parts by mass of 2-ethylhexyl acrylate (2EHA) was used, and as the di (meth) acrylate (B), ethylene oxide-modified double 5 parts by mass of phenol A dimethacrylate (EO (30) DMA), and 5 parts by mass of dipentaerythritol hexaacrylate were used as the polyfunctional (meth) acrylate (C). 5 In the same manner, an adhesive composition was prepared, an adhesive sheet was produced, and tested and evaluated.

[Comparative Example 6]

The formulation composition was 74 parts by mass of the prepolymer (X1), 4 parts by mass of acrylic acid (AA) as the monofunctional (meth) acrylic monomer (A2) containing a polar group, and 4-hydroxybutyl acrylate ( 4HBA) 1 part by mass as ethylene oxide-modified bisphenol A dimethacrylate (EO (2) DMA) as di (meth) acrylate (B) and 1 part by mass as polyfunctional (meth) 20 parts by mass of dipentaerythritol hexaacrylate of acrylate (C), other than An adhesive composition was prepared in the same manner as in Example 1, an adhesive sheet was produced, and tests and evaluations were performed.

[Comparative Example 7]

The formulation composition was 82 parts by mass of the prepolymer (X4) and 5 parts by mass of 4-hydroxybutyl acrylate (4HBA) as the monofunctional (meth) acrylic monomer (A2) containing a polar group. 10 parts by mass of ethylene oxide-modified bisphenol A dimethacrylate (EO (2) DMA) of (meth) acrylate (B) as a polyfunctional (meth) acrylate (C) PEG ( Polyethylene glycol (polyethylene glycol) 600 diacrylate 3 parts by mass, except that an adhesive composition was prepared in the same manner as in Example 1, an adhesive sheet was produced, and tested and evaluated.

[Comparative Example 8]

As the (meth) acrylic acid alkyl ester (A1), 50 parts by mass of 2-ethylhexyl acrylate (2EHA) and 40 parts by mass of n-butyl acrylate (BA) were used as monofunctional (methyl) groups containing a polar group. ) The acrylic monomer (A2) is 5 parts by mass of acrylic acid (AA), and the di (meth) acrylate (B) is ethylene oxide-modified bisphenol F diacrylate (EO (2) Except for 5 parts by mass of the FDA, an adhesive composition was prepared in the same manner as in Example 5 to produce an adhesive sheet.

The formulation composition of the adhesive composition of an Example and a comparative example is shown in Table 2.

Various evaluations were performed using the adhesive sheets obtained in Examples and Comparative Examples.

<Production of laminated body, various test methods and evaluation methods> (Production of laminated body)

One side of each of the adhesive sheets obtained in the examples and comparative examples was laminated on a multilayer sheet having an acrylic resin and a hard coating layer on the surface layer of a polycarbonate sheet having a width of 55 mm, a length of 80 mm, and a thickness of 2 mm. (Iupilon Sheet MR58, manufactured by Mitsubishi Gas Chemical Co., Ltd.). The conductive side of a transparent conductive film (manufactured by Tetolight TCF Oike Industry Co., Ltd.) was laminated on the other side of the adhesive sheet, and the protruding portion was cut according to the size of the polycarbonate sheet. The autoclave treatment was performed at 40 ° C. and 0.5 MPa for 30 minutes to obtain a bonded test piece.

(Initial transparency, adhesion)

After the initial transparency of the bonded test piece was visually observed, the initial adhesion was measured.

After cutting each adhesive sheet with a release sheet to a width of 25 mm and a length of 50 mm, the peeled polyester film was peeled off, and then pressed onto the polycarbonate surface of Iupilon MR58 with a 2 kgf load roller, and left at room temperature for 30 minute. Thereafter, using a tensile tester (model: Autograph AGS-J, manufactured by Shimadzu Corporation), in accordance with JIS-Z 0237, the peeling force at 180-degree peeling at a tensile speed of 300 mm / min was measured, and This peeling force was set as an initial adhesive force (N / 25 mm).

(Damp and heat resistance evaluation)

The above-mentioned bonded test pieces were stored in a hot and humid environment (85 ° C / relative humidity 85%) for 24 hours, and each bonded test piece after storage was visually observed. The "foaming, bulging, peeling", "transparency", and "color change" were evaluated according to the following criteria.

"Foaming, bulging, peeling"

◎: No foaming, bulging or peeling at all

￮: Almost no foaming, bulging, or peeling.

×: Foaming, bulging, and peeling can be visually confirmed.

"Transparency"

：: There is no change at all compared to the state before the test, and it is transparent.

￮: There is almost no change from the state before the test, and it is almost transparent.

×: Whiter than the state before the test.

"Color changes"

：: No change from the state before the test, and colorless.

￮: There is almost no change from the state before the test, and it is almost colorless.

×: Compared with the state before the test, the color was yellow.

(Gel fraction)

Approximately 0.5 g of the adhesive sheet produced between the polyester films subjected to the peeling treatment was weighed to obtain a weight W1 (g). This was collected in a sample bottle, about 50 g of ethyl acetate was added, and it was left to stand at 40 ° C for 24 hours. The contents of this sample bottle were filtered with a 150-mesh stainless steel wire mesh (weight W2 (g)), and the total weight W3 (g) after drying the wire mesh and the residue at 100 ° C for 1 hour Perform the measurement. The gel fraction was calculated from the measured values by the following formula 1.

The evaluation results are shown in Table 3.

The initial transparency is transparent in any of the bonding test pieces of Examples 1 to 14 and Comparative Examples 1 to 8. However, after the humidity and heat resistance test, all the examples had no change in transparency and color. On the other hand, Comparative Examples 1 to 3, 5, and 8 were whitened, and Comparative Example 5 was colored yellow.

Further, all of Examples 1 to 17 had no foaming, bulging, and peeling after the moist heat whitening resistance test, and had durability. On the other hand, Comparative Examples 1 to 7 all had foaming, bulging, and peeling after the moisturizing heat resistance test. The durability is deteriorated.

Since the adhesive composition of the present invention contains a di (meth) acrylate (B) having a bisphenol A structure, it is difficult to cause whitening and improve transparency.

The reason is presumed to be as follows. It is thought that the reason for the poor transparency of the adhesive is that the three-dimensional polymer structure becomes non-uniform, forming a space where water molecules invade. It is believed that the adhesive composition of the present invention has a bis electron A structure in which π electrons pull each other (π electron interaction), the polymer structure formed becomes uniform, and the space for water molecules to invade is limited (narrowed), Therefore, it becomes difficult for water molecules to invade, and it is difficult to produce moist heat whitening.

[Industrial availability]

Since the adhesive composition, the adhesive sheet, and the laminate of the present invention are excellent in moisture and heat whitening resistance, moisture and heat yellowing resistance, and durability, they can be used for bonding transparent plastics, such as the manufacture of touch panel modules.

1‧‧‧ double-sided adhesive sheet with release sheet

11‧‧‧ Adhesive layer

12a‧‧‧ peeling sheet

12b‧‧‧ peeling sheet

Claims (7)

An adhesive composition comprising at least one of (A) a monofunctional (meth) acrylic monomer and a prepolymer obtained by polymerizing a monofunctional (meth) acrylic monomer. (B) a di (meth) acrylate having a bisphenol A structure represented by the following general formula (1), and (C) a polyfunctional (meth) acrylate other than the above (B); and The total mass of (A), (B), and (C) above includes 72.5 to 97% by mass of (A), 3 to 25% by mass of (B), and 0 to 2.5% by mass of (C); (In the general formula (1), R ^a represents a hydrogen atom or a methyl group, R ^b represents an alkylene group having 2 to 4 carbon atoms; m and n each independently represent an integer of 1 to 15; m + n is 2 to 30; Integer). For example, the adhesive composition of claim 1 contains a polymerization initiator (D) in an amount of 0.05 to 3.5% by mass based on the total mass of the above (A), (B), and (C). For example, the adhesive composition of claim 1 or 2 does not contain an isocyanate group-containing compound having two or more isocyanate groups in the molecule. An adhesive sheet having an adhesive layer comprising a hardened body of the adhesive composition according to any one of claims 1 to 3. An adhesive sheet with a release sheet is characterized in that a release sheet is provided on one surface of the adhesive layer of the adhesive sheet as in claim 4 or on both surface areas. A laminated body characterized in that an adhesive layer of an adhesive sheet as claimed in claim 4 is adhered to a transparent plastic. The laminated body according to claim 6, wherein the transparent plastic is polycarbonate.