JP2000265145A - Photocuring type adhesive composition and method of bonding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocuring type adhesive composition which has excellent surface tackiness and excellent initial adhesive force at ordinary temperature before cured and is quickly cured to produce the cured product having excellent adhesive strength, water resistance, heat resistance and the like without requiring a thermal curing process when irradiated with light. SOLUTION: This photocuring type adhesive composition comprises an acrylic polymer, a photocation-polymerizable compound, and a photocation- polymerization initiator. Therein, the photocation-polymerizable compound contains >=20 wt.% of at least one epoxy resin selected from the group consisting of naphthalene type epoxy resins, biphenyl type epoxy resins, and fluorene type epoxy resins. The method for bonding bonding members to each other comprises coating one or both of the bonding members with the photocuring type adhesive composition and then irradiating the coated photocuring type adhesive composition with light to cure the coated adhesive composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a photocurable adhesive composition and a bonding method using the same.

[0002]

2. Description of the Related Art Generally, an adhesive is in a liquid state, and is applied to a joining member (adherend) with a brush or a roller, and then joined, and then solidified by drying of a solvent or a reaction for increasing the molecular weight of a main component. Thereby, the bonding members are bonded to each other, and excellent bonding performance such as excellent bonding strength is exhibited. However, it is necessary to fix the joining member by some method until the initial adhesive strength is developed, because the work of applying to the joining member is complicated, or the drying of the solvent and the reaction of increasing the molecular weight of the main component require a certain amount of time. There are restrictions in terms of handling workability.

[0003] On the other hand, generally, an adhesive is supplied as an adhesive sheet or an adhesive tape in a state of being coated and dried on a film-like support in advance. The dried adhesive is a semi-solid viscoelastic material with excellent surface tackiness (tack) and initial adhesive strength, and can be pressure-bonded to bonding members with weak pressure. Excellent. However, on the other hand, there is a disadvantage that it is not possible to obtain a bonding strength as strong as an adhesive.

[0004] In recent years, in order to make use of the advantages of these adhesives and pressure-sensitive adhesives, and to make up for their drawbacks, they have excellent handling operability and simplicity like a pressure-sensitive adhesive at the time of bonding, and have some properties after bonding. So-called post-curing adhesives capable of exhibiting excellent adhesive performance like adhesives by rapidly solidifying by a method have been studied.

[0005] As an example of the pressure-sensitive adhesive tape using the post-curing adhesive, for example, JP-A-63-193980 discloses a monofunctional (meth) acrylic monomer represented by a specific general formula. A compound having at least two or more (meth) acryloyl groups in one molecule, 0.01 to 10 parts by weight, and a heat-resistant epoxy resin 50 to 50 parts by weight
A composition containing 80 parts by weight and 0.2 to 20 parts by weight of the imidazole compound (100 parts by weight of the above four components) is provided on a substrate, and the composition is irradiated with ultraviolet rays or radiation to give the composition. A thermosetting adhesive tape characterized by being semi-cured "is disclosed. This is a concept that a (meth) acrylic polymer is used to develop surface tackiness (tack) and initial tackiness, and after bonding, heat-resistant epoxy resin is cured by heat curing to develop strong adhesive strength. .

However, in the case of the photocurable composition as disclosed in the above disclosure, in order to cure the heat-resistant epoxy resin,
Since it requires heat curing at about 150 ° C., it is difficult to apply to heat-sensitive adherends such as, for example, vinyl chloride resin and urethane resin, and there are restrictions on storage stability at room temperature, There are problems such as the necessity of storing at low temperature in order to obtain good storage stability.

As another example of the post-curing adhesive, for example, Japanese Patent Application Laid-Open No. 5-506465 discloses "(meta)
It is characterized by comprising at least one or more radical photopolymerization components such as acrylate monomers, at least one or more cationic photopolymerization components such as epoxy monomers, and at least one or more organometallic complex salt initiators. Pressure sensitive adhesives "are disclosed. This is to form a (meth) acrylate polymer having surface tackiness (tack) and initial tackiness by photoradical polymerization of a radical photopolymerization component such as a (meth) acrylate monomer by light irradiation. Along with the cationic photopolymerization of a cationic photopolymerization component such as an epoxy monomer,
The idea is to develop strong adhesive strength.

However, in the case of the pressure-sensitive adhesive disclosed in the above disclosure, since a (meth) acrylate-based monomer or an epoxy monomer is used, adverse effects on the environment due to volatile components and low viscosity and excessive fluidity are caused. There are problems such as insufficient shape retention and easy contamination of the periphery.

Further, as another example of the post-curing adhesive, for example, in JP-A-9-279103, "a high molecular weight polymer such as an acrylic polymer, a resin having an epoxy group, and a cationic photopolymerization initiator" Curable adhesive sheet comprising an agent "is disclosed. This is because a sticky polymer such as an acrylic polymer develops surface tackiness (tack) at room temperature and initial tackiness at room temperature, and is irradiated with light to cause a resin having an epoxy group to undergo photocationic polymerization to produce a strong polymer. The idea is to develop adhesive strength.

However, in the case of the curable adhesive sheet disclosed in the above disclosure, since an acrylic polymer is used, when a metal such as SUS is bonded, for example, water-resistant or warm water-resistant (hereinafter simply referred to as “water-resistant”). ) Is inferior.

As described above, a post-curing adhesive which combines excellent handling workability and simplicity such as an adhesive with strong adhesive strength such as an adhesive, and is also excellent in water resistance and heat resistance. At present, the agent has not been put to practical use.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention has excellent surface tackiness (tack), initial tackiness and good storage stability at room temperature before curing. In addition, by irradiating light before or after joining of the joining member, it is quickly cured without the need for heat curing, and after curing, is a photo-curing type which exhibits excellent adhesive strength, water resistance, heat resistance and the like. An object of the present invention is to provide a pressure-sensitive adhesive composition and a method for bonding a bonding member using the pressure-sensitive adhesive composition.

[0013]

The photocurable adhesive composition according to the invention described in claim 1 (hereinafter referred to as "first invention") comprises an acrylic polymer, a cationic photopolymerizable composition, A photocurable adhesive composition containing a photocationic polymerization initiator, wherein the photocationically polymerizable compound is selected from the group consisting of a naphthalene type epoxy resin, a biphenyl type epoxy resin and a fluorene type epoxy resin. It is a cationic photopolymerizable compound containing at least one type of epoxy resin in an amount of 20% by weight or more.

The photocurable adhesive composition according to the invention of claim 2 (hereinafter referred to as "second invention") comprises an acrylic polymer, a cationic photopolymerizable compound, a cationic photopolymerization initiator and a resin. A photocurable adhesive composition containing a cyclic epoxy resin, wherein the total amount of the acrylic polymer, the photocationic polymerizable compound and the photocationic polymerization initiator is 100 parts by weight, Epoxy resin 1
It is characterized by containing 10 parts by weight.

The photocurable adhesive composition according to the invention of claim 3 (hereinafter referred to as "third invention") is a photocurable adhesive composition according to the first or second invention. In the above, the acrylic polymer has an alkyl group having 2 to 2 carbon atoms.
It is a copolymer of 20 acrylic monomers and an epoxy group-containing acrylic monomer having at least one epoxy group in the molecule.

The photocurable adhesive composition according to the invention of claim 4 (hereinafter referred to as "the fourth invention") is a photocurable adhesive composition according to the first invention or the second invention. In the above, the acrylic polymer is combined with the acrylic monomer in the first
It is a copolymer obtained by subjecting a photo-curable adhesive composition according to the invention or the second invention to a photo-radical polymerization of a composition excluding an acrylic polymer from the photo-curable adhesive composition.

The photocurable adhesive composition according to the invention of claim 5 (hereinafter referred to as the "fifth invention") comprises the photocurable adhesive composition according to the first to fourth inventions. The reaction rate of epoxy groups in the cured product irradiated with light is 40 to 80 mol%.

Further, the invention according to claim 6 (hereinafter referred to as “6
Inventive "), the joining method of the joining member is the first method.
The photocurable adhesive composition according to any one of the inventions to the fifth invention is applied to one or both of the joining members, and the adhesive composition is irradiated with light before or after joining the joining members. Then, a step of photo-cationically polymerizing the above-mentioned adhesive composition and curing the same is included.

The photocurable pressure-sensitive adhesive composition according to the first to fifth inventions (hereinafter referred to as "the present invention") has excellent surface properties at room temperature with the obtained photocurable pressure-sensitive adhesive composition. In order to impart tackiness (tack) and initial tackiness, an acrylic polymer is contained as an essential component.

Excellent surface tackiness at normal temperature (tack)
In order to obtain high initial adhesive strength, it is necessary that the balance between the wettability and the cohesive force with respect to the joining member (the adherend) is appropriate. In the present invention, the balance between the wettability and the cohesive force is required. An acrylic polymer is used in order to make the composition suitable.

The acrylic polymer contained as an essential component in the photocurable adhesive composition according to the first and second inventions is not particularly limited. For example, an alkyl (meth) acrylate monomer , A copolymer of two or more alkyl (meth) acrylate monomers, a copolymer of an alkyl (meth) acrylate monomer and an acid component or a polymerizable monomer copolymerizable with the alkyl (meth) acrylate monomer And the like, and are preferably used. In addition, (meth) acrylate here means acrylate or methacrylate.

The above acrylic polymers may be used alone or in combination of two or more.

Although not particularly limited, the acrylic polymer has a glass transition temperature (Tg) of 20 ° C.
The following are preferred. If the glass transition temperature of the acrylic polymer exceeds 20 ° C., the resulting photocurable pressure-sensitive adhesive composition may have insufficient surface tackiness (tack) and initial tackiness.

The alkyl (meth) acrylate monomer is not particularly limited, but, for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, n-octyl (meth) acrylate, iso-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Various alkyl (meth) acrylate monomers such as iso-nonyl (meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, and eicosyl (meth) acrylate are listed. Species or more are preferably used, and among them, an alkyl (meth) acrylate monomer having an alkyl group having 2 to 20 carbon atoms is more preferably used.

The acid component and the polymerizable monomer copolymerizable with the alkyl (meth) acrylate monomer are not particularly limited.
Acid components such as acrylic acid and maleic anhydride, acrylonitrile, urethane acrylate, styrene, vinyl acetate, glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, ε- (poly) caprolactone acrylate, tetrahydrofuranyl acrylate, N Polymerizable monomers such as -vinylpyrrolidone, N-vinylcaprolactone, and N-vinylpiperidine; and one or more of these are suitably used.

When the acrylic polymer is a copolymer of an alkyl (meth) acrylate monomer and the above-mentioned acid component or polymerizable monomer copolymerizable with the alkyl (meth) acrylate monomer, there is no particular limitation. However, it is preferable that the unit of the alkyl (meth) acrylate monomer in the copolymer be 20% by weight or more. When the unit of the alkyl (meth) acrylate monomer is less than 20% by weight, the resulting photocurable pressure-sensitive adhesive composition has insufficient surface tackiness (tack), initial tackiness, or physical properties of a cured product. Sometimes.

The polymerization method for obtaining the acrylic polymer is not particularly limited, and may be any polymerization method such as a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, and a photopolymerization method. Is also good.

The photocurable pressure-sensitive adhesive composition according to the present invention has excellent photocationic polymerizability imparted to the resulting photocurable pressure-sensitive adhesive composition, and is subjected to photocationic polymerization by irradiation with light. In order to make the cured product exhibit excellent adhesive strength, water resistance, heat resistance, and the like, a cationic photopolymerizable compound is contained as an essential component.

The photocationically polymerizable compound is not particularly limited as long as it has at least one photocationically polymerizable functional group in the molecule, and is not particularly limited. Various compounds having a photocationically polymerizable functional group such as a hydroxyl group, a vinyl ether group, an episulfide group, an ethyleneimine group, an epoxy group, and the like can be mentioned, and are preferably used. The molecular weight of the cationic photopolymerizable compound used in the present invention is not particularly limited, and may be any of a monomer, an oligomer, and a polymer.

The above cationic photopolymerizable compound may be used alone or in combination of two or more.

Among the various cationic photopolymerizable compounds, an epoxy group-containing compound having at least one epoxy group in the molecule is more preferably used.

The epoxy group is excellent in photocationic polymerizability (ring-opening polymerizability) and high in reactivity, so that the curing time can be short, and the joining process can be shortened. In addition, cured products obtained by photocationic polymerization have high cohesive strength and elasticity,
Since it exhibits various properties such as excellent adhesive strength, water resistance, heat resistance, etc., even in a process exposed to high heat such as soldering in a manufacturing process of a printed circuit board or a flexible printed board, for example, peeling and rubbing etc. Adhesion abnormality can be effectively prevented.

The epoxy group-containing compound is not particularly limited. For example, bisphenol A
Epoxy resins such as bisphenol-type epoxy resins such as epoxy resin and bisphenol F-type epoxy resin, phenol novolak-type epoxy resin, cresol novolak-type epoxy resin, glycidyl ether-type epoxy resin, and glycidylamine-type epoxy resin. And it is preferably used.

Examples of the epoxy group-containing compounds include, for example, trade names “Epicoat 1001” and “Epicoat 10”.
Bisphenol A type epoxy oligomers such as "02" (both manufactured by Yuka Shell Epoxy Co., Ltd.) may be used. Further, epoxy monomers such as glycidylated polyester, glycidylated polyurethane, glycidylated acrylic, etc. An oligomer addition polymer may be used.

The above epoxy group-containing compounds may be used alone or in combination of two or more.

The cationic photopolymerizable compound used in the present invention may be modified with another resin, if necessary, as long as the achievement of the object of the present invention is not hindered.
For example, those having a reactive functional group other than photocationically polymerizable such as a radical polymerizable unsaturated bond may be introduced.

The cationic photopolymerizable compound used in the present invention may have an adhesive force or a flexibility by modifying it by blending or adding other resin components, if necessary, as long as the object of the present invention is not hindered. The modified body may have improved properties, flexibility and the like, and such a modified body is not particularly limited. For example, CTBN (carboxyl group-containing butadiene-acrylonitrile rubber) modified epoxy resin An epoxy resin to which various rubbers such as acrylic rubber, NBR, SBR, butyl rubber and isoprene rubber are added; an epoxy resin to which various resins such as acrylic, urethane, urea, polyester and styrene are added; a chelate-modified epoxy resin; Examples thereof include polyol-modified epoxy resins, and one or more of these are suitably used.

The functional group equivalent of the photocationically polymerizable compound in the photocurable pressure-sensitive adhesive composition according to the present invention is not particularly limited, but is 150 to 5000 g-r.
It is preferably esin / mol. When the functional group equivalent is less than 150 g-resin / mol, the reactivity of the photocurable adhesive composition becomes too high, and the working time until the joining member (adherend) is joined after light irradiation. May be restricted, and conversely, the functional group equivalent is 5000 g
If it exceeds -resin / mol, the reaction rate of the photocurable adhesive composition becomes slow, and it may take a long time to cure. However, the functional group equivalent may be appropriately set depending on the required reaction rate and physical properties of the cured product,
There is no need to make a clear decision.

The mixing ratio of the acrylic polymer and the cationic photopolymerizable compound in the photocurable adhesive composition according to the present invention is not particularly limited. It is preferable that the blending amount of the acrylic polymer in the total amount of 100 parts by weight of the cationic polymerizable compound is 40 to 90 parts by weight. Total amount of acrylic polymer and cationic photopolymerizable compound 1
The amount of the acrylic polymer in 00 parts by weight is 4
If the amount is less than 0 parts by weight, the resulting photocurable pressure-sensitive adhesive composition may have insufficient surface tackiness (tack) and initial tackiness at room temperature, and conversely, an acrylic polymer and a cationic photopolymerization. When the blending amount of the acrylic polymer in the total amount of 100 parts by weight of the hydrophilic compound exceeds 90 parts by weight, the elasticity of the cured product of the obtained photocurable adhesive composition becomes low, and the adhesive strength and water resistance are reduced. , Heat resistance and the like may be insufficient.

In the photocurable adhesive composition according to the first invention, the photocationically polymerizable compound is at least one selected from the group consisting of a naphthalene type epoxy resin, a biphenyl type epoxy resin and a fluorene type epoxy resin. It is necessary to use a cationic photopolymerizable compound containing at least 20% by weight of a kind of epoxy resin.

The above three types of epoxy resins are all epoxy resins having excellent water resistance and heat resistance, and the photocurable adhesive obtained by using a cationic photopolymerizable compound containing these epoxy resins is obtained. The cured product of the agent composition by light irradiation exhibits more excellent water resistance and heat resistance.

If the content of the epoxy resin in the photocationically polymerizable compound is less than 20% by weight, the water resistance and heat resistance of the obtained photocurable adhesive composition will not be sufficiently improved.

The naphthalene type epoxy resin is an epoxy resin represented by the following general formula (1), and specific examples thereof are not particularly limited. For example, a trade name of “Epiclon HP-4032” , "Epiclon HP-
4032D "(above, manufactured by Dainippon Ink and Chemicals, Inc.), trade name" NC-7000 "(produced by Nippon Kayaku Co., Ltd.), trade name" E
SN-185 "and" ESN-365 "(all manufactured by Toto Kasei Co., Ltd.) and the like are preferably used.

Embedded image (In the formula, R ¹ and R ² represent an alkyl chain having an epoxy group, and the formula (1) includes structural isomers)

The above naphthalene type epoxy resins may be used alone or in combination of two or more.

The biphenyl type epoxy resin is an epoxy resin represented by the following general formula (2), and specific examples thereof are not particularly limited.
The trade name “YX4000” (manufactured by Yuka Shell Epoxy) and the like are mentioned, and are preferably used.

Embedded image (In the formula, R ¹ and R ² each represent an alkyl chain having an epoxy group, and R ³ , R ⁴ , R ⁵ and R ^{6 each} represent H or an alkyl chain. Formula (2) includes structural isomers )

The biphenyl type epoxy resin may be used alone or in combination of two or more.

Further, the fluorene type epoxy resin is
It is an epoxy resin represented by the following general formula (3), and specific examples thereof are not particularly limited. For example, a product name “EPON HPT-1079” (SHEL
L company) and the like, and are preferably used.

Embedded image (Wherein, R ¹ and R ² each represent an alkyl group having an epoxy group, and formula (3) includes structural isomers)

The above fluorene type epoxy resins may be used alone or in combination of two or more.

The photocurable adhesive composition according to the present invention is activated by irradiating light, generates a photocationic polymerization initiator, and has a relatively low energy to produce the photocationically polymerizable compound. In order to initiate photocationic polymerization of an epoxy group-containing acrylic polymer described below and an alicyclic epoxy resin described below, a photocationic polymerization initiator is contained as an essential component.

The cationic photopolymerization initiator may be of an ionic photoacid generating type or a nonionic photoacid generating type.

The ionic photoacid generating type cationic photopolymerization initiator is not particularly limited, and examples thereof include onium salts such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts. And organometallic complexes such as iron-allene complex, titanocene complex, and arylsilanol-aluminum complex. One or more of these are preferably used.

Specific examples of the cationic photopolymerization initiator of the ionic photoacid generating type are not particularly limited. For example, a trade name of "ADEKA OPTOMER SP15"
0 "," ADEKA OPTOMER SP170 "(manufactured by Asahi Denka Kogyo), trade name" UVE-1014 "(manufactured by General Electronics), trade name" CD-1012 "(manufactured by Sartomer), and the like. One or two of these
More than one species is preferably used.

The nonionic photoacid generating type cationic photopolymerization initiator is not particularly limited, and examples thereof include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, sulfonic acid derivative and phenol sulfone. Acid esters, diazonaphthoquinone, N-hydroxyimidosulfonate and the like are mentioned, and one or more of these are suitably used.

The above cationic photopolymerization initiator may be used alone or in combination of two or more. or,
When two or more cationic photopolymerization initiators are used in combination, multistage curing may be performed using two or more different cationic photopolymerization initiators having different effective active wavelengths.

The amount of the cationic photopolymerization initiator in the photocurable adhesive composition according to the present invention is not particularly limited, but may be, for example, one selected from the group consisting of the cationic photopolymerizable compound and the acrylic polymer. The amount is preferably such that the amount of generated cations is 0.0001 mol% or more based on 1 mol of a functional group such as an epoxy group. When the amount of the cationic photopolymerization initiator is such that the amount of cations generated per 1 mol of the functional group is less than 0.0001 mol, the photocationic polymerization reaction does not sufficiently proceed, and the curing rate is reduced. Sometimes.

In the present invention, as the photopolymerization initiator,
One or more other photopolymerization initiators such as a photoradical polymerization initiator and a photoanion polymerization initiator may be used in combination with the above-mentioned photocationic polymerization initiator which is an essential component. In this case, the wavelength of light for activating the photo-radical polymerization initiator or the photo-anionic polymerization initiator does not necessarily need to be equal to the wavelength of light for activating the photo-cationic polymerization initiator.

In the present invention, light is irradiated to activate the above-mentioned cationic photopolymerization initiator.

The light is not particularly limited, but includes, for example, microwaves, infrared rays, visible light, ultraviolet rays, X-rays, γ-rays, etc., and is preferably used. Ultraviolet light which is simple and easy to obtain and can obtain relatively high energy is more preferably used, and ultraviolet light having a wavelength of 200 to 400 nm is particularly preferably used.

The ultraviolet light is not particularly limited, but can be irradiated using an appropriate light source such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, and a xenon lamp.

In the photo-curable adhesive composition according to the second invention, the alicyclic epoxy resin is added to 100 parts by weight of the above-mentioned acrylic polymer, photo-cationic polymerizable compound and photo-cationic polymerization initiator in total. It is necessary to contain 1 to 10 parts by weight.

The alicyclic epoxy resin is an epoxy resin having excellent water resistance and heat resistance, and is obtained by adding an alicyclic epoxy resin to the photocurable adhesive composition. The cured product of the adhesive composition by light irradiation exhibits more excellent water resistance and heat resistance.

When the content of the alicyclic epoxy resin is less than 10 parts by weight based on 100 parts by weight of the total amount of the acrylic polymer, the cationic photopolymerizable compound and the cationic photopolymerization initiator, the water resistance and heat resistance are insufficient. If the content of the alicyclic epoxy resin exceeds 10 parts by weight based on 100 parts by weight of the total of the acrylic polymer, the cationic photopolymerizable compound and the cationic photopolymerization initiator, the curing at the time of light irradiation is not improved. The speed is too high, and the surface tackiness (tack) and initial tackiness are poor.

The alicyclic epoxy resin is an epoxy resin of a type in which a double bond of a cyclohexene ring is oxidized with peracetic acid to be epoxidized, and specific examples thereof are not particularly limited. For example, the product name "Epox
Alicyclic diepoxy acetal such as "y1234" (manufactured by UCC), trade name "Epoxy249"
Alicyclic diepoxy adipate such as (UCC), trade name "Epoxy221" (UCC)
And an epoxy resin such as vinylcyclohexene dioxide such as "Epoxy206" (manufactured by UCC).

The alicyclic epoxy resins may be used alone or in combination of two or more.

The photocurable adhesive composition according to the third invention is the photocurable adhesive composition according to the first or second invention, wherein the acrylic polymer has an alkyl group having 2 to 2 carbon atoms. It is necessary to use a copolymer of 20 acrylic monomers and an epoxy group-containing acrylic monomer having at least one epoxy group in the molecule.

In the above copolymer, since an epoxy group is introduced into the acrylic polymer, not only the photocationically polymerizable compound but also the acrylic polymer itself has photocationic polymerizability. A cured product of the curable pressure-sensitive adhesive composition obtained by light irradiation exhibits more excellent water resistance and heat resistance.

The acrylic monomer having an alkyl group having 2 to 20 carbon atoms is not particularly limited.
For example, ethyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, n
-Octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, iso-nonyl (meth) acrylate, dodecyl (meth) acrylate, tetradecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, eicosyl (meth) ) Acrylate and the like, and one or more of these are suitably used.

When the alkyl group of the acrylic monomer has 2 carbon atoms, the resulting photocurable adhesive composition has insufficient surface tackiness (tack) and initial tackiness. The alkyl group of the monomer has 20 carbon atoms.
If it exceeds, the cured product of the obtained photocurable pressure-sensitive adhesive composition will have poor cohesive strength, resulting in insufficient adhesive strength and heat resistance.

The epoxy group-containing acrylic monomer having at least one epoxy group in the molecule includes:
Although not particularly limited, for example, glycidyl (meth) acrylate, trade name “Cyclomer M10
(Meth) acrylates having an alicyclic epoxy group, such as "Cyclomer" series (all manufactured by Daicel Chemical Industries, Ltd.) such as "0, M101, A200", and a carboxyl group of (meth) acrylic acid and a bifunctional or more functional group. Monomers obtained by reacting an epoxy group of an epoxy compound with monomers, monomers obtained by reacting a hydroxyl group or a carboxyl group of an acrylic monomer having a hydroxyl group or a carboxyl group in a side chain with an epoxy group of a bifunctional or more epoxy compound, etc. And one or more of these are preferably used.

The method of copolymerizing the acrylic monomer having an alkyl group having 2 to 20 carbon atoms with the epoxy group-containing acrylic monomer is not particularly limited, and may be a solution polymerization method, an emulsion polymerization method, or a suspension polymerization method. , Bulk polymerization, photopolymerization and the like.

The photocurable pressure-sensitive adhesive composition according to the fourth invention is the photocurable pressure-sensitive adhesive composition according to the first or second invention, wherein an acrylic polymer is used as the acrylic polymer, Wherein the acrylic polymer is excluded from the photocurable adhesive composition according to the above, that is, at least one epoxy resin selected from the group consisting of the naphthalene type epoxy resin, the biphenyl type epoxy resin and the fluorene type epoxy resin Or a composition comprising a photo-cationic polymerizable compound and a photo-cationic polymerization initiator containing 20% by weight or more, or a composition in which an acrylic polymer is excluded from the photo-curable adhesive composition according to the second invention, that is, A copolymer obtained by subjecting a composition comprising a photocationically polymerizable compound, a photocationic polymerization initiator and an alicyclic epoxy resin to photoradical polymerization. Body it is necessary to use.

Since the above copolymer has an epoxy group introduced into the acrylic polymer, not only the above-mentioned cationic photopolymerizable compound but also the acrylic polymer itself has photocationic polymerizability. A cured product of the curable pressure-sensitive adhesive composition obtained by light irradiation exhibits more excellent water resistance and heat resistance.

The method for the photoradical polymerization is not particularly limited. For example, a photoradical polymerizable composition comprising an acrylic monomer, the above-mentioned composition to be copolymerized with the acrylic monomer, and a photoradical polymerization initiator is prepared. After doing
In order to prevent radical polymerization reaction inhibition by oxygen in the air or dissolved oxygen in the photo-radical polymerizable composition, the photo-radical polymerizable composition is coated with, for example, a polyethylene terephthalate (PET) film or a Teflon film, and the like. Obtaining a desired photo-radical copolymerized acrylic polymer by a method of irradiating light through a film or a method of irradiating the photo-radical polymerizable composition with light under an inert gas atmosphere such as nitrogen gas. Can be done.

The photo-radical polymerization initiator is activated by light having a wavelength longer than the photosensitive wavelength of the photo-cationic polymerization initiator. Even if a conventionally known photo-radical polymerization initiator is used alone, Good, or two or more kinds may be used in combination.

The wavelength of light irradiated for photoradical polymerization is preferably light substantially free from light having a wavelength shorter than 360 nm, and the method for obtaining such light is not particularly limited. Although it is not something, for example, using a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light, a microwave-excited mercury lamp, a metal halide lamp, etc. And a method using a fluorescent lamp having substantially the maximum emission wavelength in the 420 nm region, which does not substantially contain light having a wavelength of, for example, is preferably employed.

The photo-curable adhesive composition according to the fifth invention is the same as the photo-curable adhesive composition according to the first to fourth inventions described above, except that Is required to be 40 to 80 mol%.

The reaction rate of the epoxy group in the cured product is 40 to 8
By setting it to 0 mol%, the cohesive force and elastic modulus of the cured product become appropriate, and excellent balance of tensile adhesive strength, peel adhesive strength, elasticity, impact resistance and the like are exhibited.

The reaction rate of the epoxy group in the cured product is 40
If it is less than mol%, the cohesive force of the cured product will not be sufficiently exhibited, and the tensile adhesive strength, water resistance, heat resistance, etc. will be insufficient, and conversely, the reaction rate of the epoxy group in the cured product will be 80 mol%. If it exceeds, the elastic modulus of the cured product becomes too high, and the stress relaxation property at the time of peeling becomes poor, so that peel adhesive strength, elasticity, impact resistance and the like become insufficient.

The reaction rate of the epoxy group in the cured product is obtained by the following equation. Conv (mol%) = {(Z ₀ −Z ₁ ) / Z ₀ } × 10
0 Here, Conv (mol%): reaction rate of epoxy group Z ₀ (mol / g): content of epoxy group in the photocurable adhesive composition before irradiation with light Z ₁ (mol / g) ): Content of epoxy group in photocurable adhesive composition after light irradiation

The epoxy group content in the photocurable pressure-sensitive adhesive composition can be determined by the hydrochloric acid-dioxane method by the following method.

To a fixed amount of the photocurable adhesive composition, a mixed solution of hydrogen chloride dioxane solution / ethanol = 1/1 (weight ratio) was added, and the mixture was stirred at room temperature for 5 hours. The back titration of hydrogen chloride with potassium hydroxide is performed, and it is determined by the following equation. Z (mol / g) = (S ₁ −S ₂ ) × C × f / (W _S ×
1000) Here, Z (mol / g): Epoxy group content S ₁ (ml): Titration of potassium hydroxide in ethanol solution required for blank test S ₂ (ml): Potassium hydroxide required for main test C (mol / l): Concentration of potassium hydroxide in ethanol solution used for titration f: Factor of potassium hydroxide in ethanol solution used for titration _WS (g): Amount of titrated sample However, when an acid group such as a carboxyl group is present in the titration sample, the content of the acid group is determined in advance, and the value is calculated as Z
The value subtracted from the above was defined as the epoxy group content.

The photocurable pressure-sensitive adhesive composition according to the present invention contains essential components such as an acrylic polymer, a photocationic polymerizable compound and a photocationic polymerization initiator (first invention), or an acrylic polymer, In addition to the cationically polymerizable compound, the cationic photopolymerization initiator, and the alicyclic epoxy resin (second invention), the surface tackiness (tack) and the initial tackiness at room temperature, if necessary, as long as the object of the present invention is not hindered. One of various additives such as a tackifying resin for further improving the force, a filler, a bulking agent, a thixotropic agent, a softener, a plasticizer, a stabilizer, an antioxidant, a flame retardant, a colorant, and an organic solvent. Species or two or more species may be contained.

The tackifying resin is not particularly restricted but includes, for example, rosin resin, modified rosin resin, terpene resin, terpene phenol resin, aromatic modified terpene resin, C5 or C9 petroleum. Resins, cumarone indene resins and the like, and one or more of these are suitably used.

The method for producing the photocurable pressure-sensitive adhesive composition according to the present invention is not particularly limited, and a mixer such as a homodisper, a homomixer, a universal mixer, a planetarium mixer, a kneader, and a three-roller is used. Acrylic polymer, photocationic polymerizable compound and photocationic polymerization initiator (first invention), or acrylic polymer, photocationic polymerizable compound, photocationic polymerization initiator which are essential components at room temperature or under heating And a predetermined amount of the alicyclic epoxy resin (second invention) and one or two or more of the above-mentioned various additives to be contained as required are uniformly mixed to obtain a desired photocurable epoxy resin. An adhesive composition can be obtained. In addition, it is preferable that the said manufacture is performed in the state which interrupted light.

The photocurable adhesive composition of the present invention thus obtained is applied as it is to one or both surfaces of a joining member (substrate), and light is applied before or after joining of the joining member. Irradiation, photo-cation polymerization, and curing may be performed. However, in order to obtain better handling workability and simplicity, a photo-curable adhesive sheet (hereinafter simply referred to as “adhesive sheet”) that has been processed into a pressure-sensitive adhesive sheet in advance. Adhesive sheet "). The adhesive sheet is usually preferably a double-sided adhesive sheet, but may be a single-sided adhesive sheet in some cases.

The method of processing the above-mentioned adhesive sheet is not particularly limited. For example, various methods such as a roll coating method, a gravure coating method and an extrusion coating method may be applied to a release-treated sheet-like support. After applying the photocurable adhesive composition by a coating method, and after a drying step and a cooling step as necessary, the surface of the applied photocurable adhesive composition is, for example, a polyethylene sheet. A desired adhesive sheet can be obtained by protecting with a release sheet as described above and winding it up. In the above-mentioned processing, when the photocurable adhesive composition is solid or semi-solid, or has a high viscosity even in a liquid state and is difficult to apply, for example, it is diluted with an organic solvent or heated and melted. By doing so, the viscosity may be reduced.

The support and the release sheet are not particularly limited. For example, polyethylene terephthalate, polyethylene naphthalate, polyethylene,
Polypropylene, polycarbonate, nylon, polyarylate, polysulfone, polyethersulfone, polyetheretherketone, polyphenylenesulfide, polystyrene, polyacrylic, polyvinylacetate, triacetylcellulose, diacetylcellulose, cellophane and the like are preferably used. The support and release sheet are not particularly limited, but preferably have a thickness of 1 μm or more, more preferably 10 μm or more.
μm or more. If the thickness of the support or the release sheet is less than 1 μm, the strength may be low, and the support or the release sheet may be torn during use.

The pressure-sensitive adhesive sheet thus obtained is not particularly limited, but has a thickness of 1 to 200.
0 μm, more preferably 10 to 1 μm.
000 μm. If the thickness of the adhesive sheet itself is less than 1 μm, the adhesiveness of the adhesive sheet may be affected by unevenness of the surface of the joining member (substrate), and conversely, the adhesive sheet itself may be affected. When the thickness exceeds 2000 μm,
The cure time may be excessively long.

The pressure-sensitive adhesive sheet is not particularly limited, but preferably has a surface tackiness (tack) at room temperature of 5 or more in ball tack.
More preferably, it is 10 or more. When the surface tackiness (tack) is less than 5 in ball tack, workability and convenience at the time of joining the joining members may be reduced.

Next, in the joining method of the joining member according to the sixth invention, the photocurable adhesive composition according to any one of the first to fifth inventions described above is applied to one or both of the joining members. Before or after the joining of the joining member, a step of irradiating the adhesive composition with light to cause cationic cationic polymerization of the adhesive composition and to cure the adhesive composition is provided. Here, the application of the photocurable adhesive composition refers to not only the case where the photocurable adhesive composition is applied as it is, but also the photocurable adhesive sheet. And the case of application in the form of

In the above-mentioned joining method, the time of irradiating the light-curable pressure-sensitive adhesive composition with light is determined by the time when the light-curable pressure-sensitive adhesive composition is applied to the joining member coated with the light-curable pressure-sensitive adhesive composition. It may be either before or after joining with the joining member to which the composition has not been applied or to which the composition has been applied.

For example, when at least one of the joining members (adherend) is light-transmissive, a photocurable adhesive composition or a photocurable adhesive sheet is applied to at least one of the joining members. After pasting, it is joined to the other joining member and irradiated with light from the light-transmissive joining member surface to photo-cationically polymerize the photo-curable adhesive composition or the photo-curable adhesive sheet. , Should be cured. In the case of this method, it is preferable to irradiate light as soon as possible after the joining members are joined in order to shorten the time of the entire joining process.

When both the joining members are not light-transmitting, the photocurable adhesive composition or the photocurable adhesive sheet is applied or affixed to at least one of the joining members. After irradiating the adhesive composition surface or the adhesive sheet surface with light, it is joined to the other joining member, and the photocurable adhesive composition or the photocurable adhesive sheet is subjected to photocation polymerization, Just let it cure. In the case of this method, in order to smoothly join the one joining member and the other joining member, the joint between the two joining members is made as quickly as possible after light irradiation, preferably within 10 minutes. It is preferred to do so.

In any of the above methods, the curing of the photo-curable adhesive or the photo-curable adhesive sheet by the photocationic polymerization reaction proceeds at room temperature in a short time, and the cured product has excellent adhesive strength and It exhibits water resistance, heat resistance, etc.

As described above, the light for irradiating the light is not particularly limited.
Microwaves, infrared rays, visible light, ultraviolet rays, X-rays, γ-rays and the like can be mentioned and are preferably used. Among them, ultraviolet rays which are easy to handle and simple and can obtain relatively high energy are more preferable. Ultraviolet rays having a wavelength of 200 to 400 nm are particularly preferably used.

As described above, the ultraviolet light is not particularly limited, but can be irradiated using an appropriate light source such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, and a xenon lamp.

Further, in order to further accelerate the curing reaction of the photocurable adhesive composition or the photocurable adhesive sheet and to further shorten the curing time, the above-mentioned light irradiation, heating and humidification, etc. May be used in combination.

[0098]

The photocurable pressure-sensitive adhesive composition according to the present invention is excellent in surface tackiness (tack) and initial tackiness at room temperature since it contains an acrylic polymer. Further, since it contains a photocationically polymerizable compound, it is rapidly cured by a photocationic polymerization reaction when irradiated with light, and exhibits excellent adhesive strength, water resistance, heat resistance and the like after curing. Therefore, with excellent handling workability and simplicity such as adhesive,
It has both excellent adhesive strength such as an adhesive, water resistance, heat resistance and the like.

The method for joining a joining member according to the sixth aspect of the present invention uses the above-mentioned photocurable adhesive composition or the photocurable adhesive composition which has been processed beforehand. Since the irradiation is performed by irradiating the sheet with light, a joined body having excellent adhesive strength, water resistance, heat resistance and the like can be easily obtained in a short time with good workability.

[0100]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by weight”.

(Example 1)

(1) Preparation of photocurable adhesive composition 70 parts of butyl acrylate resin (weight average molecular weight 900,000) as an acrylic polymer and crosslinked NBR fine particle dispersed epoxy resin (trade name) as a photocationic polymerizable compound 5 parts of "EPR21" (manufactured by Asahi Denka Kogyo KK) and a naphthalene type epoxy resin (trade name "Epiclon HP-4032")
D ", manufactured by Dainippon Ink and Chemicals, Inc.) 25 parts, a trade name of" ADEKA OPTOMER SP17 "as a cationic photopolymerization initiator
0 "(manufactured by Asahi Denka Kogyo Co., Ltd.) and 100 parts of methyl ethyl ketone (MEK) as an organic solvent in an atmosphere of 23 ° C. in a homodisper-type stirring mixer (trade name“ Homodisper L-type ”; Stirring speed 30
The mixture was uniformly stirred and mixed at 00 rpm to prepare a photocurable adhesive composition.

(2) Preparation of Photocurable Adhesive Sheet A 50 μm-thick polyethylene terephthalate (PET) film subjected to a release treatment was used as a support, and the PET film was released using a roll coater. The photocurable adhesive composition obtained above was coated on the surface with a coating thickness (d
ry) was applied to be 50 μm and dried to obtain a photocurable pressure-sensitive adhesive sheet. Next, on the surface of the adhesive composition of the obtained photocurable pressure-sensitive adhesive sheet, a release-treated surface of a polyethylene-laminated high-quality paper having been subjected to silicone release treatment as a protective film was laminated, and the photocurable An adhesive sheet was prepared.

(3) Preparation of bonded body While peeling off the protective film, a photocurable adhesive sheet was applied to a 50 μm thick stainless steel (SUS) foil.
Thermal lamination was performed at 0 ° C. At this time, the lamination pressure (linear pressure) was 3 kg / cm, and the lamination speed was 2 m / min. Next, the release PET film is peeled off, and the adhesive composition surface of the photocurable adhesive sheet is irradiated with ultraviolet rays having a wavelength of 365 nm using an ultrahigh pressure mercury lamp so that the irradiation intensity becomes ² J / cm ^2. Immediately after that, a 50 μm-thick SUS foil was heat-laminated at 100 ° C. on the surface of the adhesive composition to produce a joined body. In addition, the reaction rate of the epoxy group in the photocurable adhesive composition after irradiation with light was determined by the above method, and was 63 mol%.

(4) Evaluation The performance (initial adhesive strength, normal adhesive strength, water-resistant adhesive strength) of the joined body obtained above and the performance (storage stability) of the photocurable adhesive sheet were evaluated by the following methods. did. The results were as shown in Table 1.

Initial adhesive strength: 23 ° C.-50% R
After leaving for 30 minutes in an atmosphere of H, the sheet was cut to a width of 10 mm, and the peeling speed was 50 m using a Tensilon type tensile tester.
A 180-degree angle peel test was performed at m / min, and the initial adhesive strength (g /
10 mm).

Normal bonding strength: Bonded body at 23 ° C.-50%
After being left for 24 hours in an atmosphere of RH, it was cut into a width of 10 mm, and a 180-degree angle peeling test was performed under the same conditions as in the above to measure the normal adhesive strength (g / 10 mm).

Water-resistant adhesive strength: The joined body was heated at 23 ° C.-50%
After leaving for 24 hours in an atmosphere of RH, it was cut to a width of 10 mm and immersed in warm water of 40 ° C. for 100 hours. Then
After being taken out of the warm water and left for 24 hours in an atmosphere of 23 ° C. and 50% RH, 180
Degree angle peel test was performed, and the water-resistant adhesive strength A (g / 10 mm)
Was measured. In the same manner as above, 100
Take out the bonded body immersed in the hot water for
After drying for 1 hour under the same conditions as in the above, a 180-degree angle peel test was performed, and the water-resistant adhesive strength B (g / 10 mm) was measured.

Storage stability The photocurable pressure-sensitive adhesive sheet was left for (a) one month in a dark place at 40 ° C. for one month and (b) six months in a dark place at 23 ° C. Evaluation was performed to confirm whether or not there was a change in performance after storage with respect to the initial performance.

Example 2 In the preparation of the photocurable adhesive composition, as the epoxy resin to be contained in the photocationically polymerizable compound, instead of 25 parts of a naphthalene type epoxy resin “Epiclon HP-4032D”, Photocurable adhesive composition and photocurable adhesive in the same manner as in Example 1 except that 25 parts of a biphenyl type epoxy resin (trade name “YX4000”, manufactured by Yuka Shell Epoxy Co., Ltd.) was used. A sheet and a joined body were obtained. In addition, the reaction rate of the epoxy group in the photocurable adhesive composition after irradiation with light was determined by the above method, and was 64 mol%.

Example 3 In the preparation of the photocurable adhesive composition, as the epoxy resin to be contained in the photocationically polymerizable compound, instead of 25 parts of a naphthalene type epoxy resin “Epiclon HP-4032D”, Fluorene type epoxy resin (trade name “EPON HPT-107”
9 "(manufactured by SHELL) except that 25 parts were used to obtain a photocurable adhesive composition, a photocurable adhesive sheet, and a joined body. In addition, the reaction rate of the epoxy group in the photocurable adhesive composition after light irradiation was determined by the above method, and was 60 mol%.

(Examples 4, 5, and 6) In the preparation of the photocurable adhesive composition, butyl acrylate / glycidyl acrylate = 95/5 (weight) was used instead of 70 parts of butyl acrylate resin as the acrylic polymer. Photocurable pressure-sensitive adhesive composition and photocurable pressure-sensitive adhesive in the same manner as in Examples 1, 2, and 3, respectively, except that 70 parts of a copolymer resin (weight average molecular weight: 900,000) was used. A sheet and a joined body were obtained. In addition, when the reaction rate of the epoxy group in the photocurable adhesive composition after light irradiation was determined by the above method, Example 4 was 70 mol%, Example 5 was 65 mol%,
Example 6 was 65 mol%.

(Comparative Example 1) In the preparation of a photocurable adhesive composition, a crosslinked NBR fine particle-dispersed epoxy resin was used without adding a naphthalene type epoxy resin “Epiclon HP-4032D” as a photocationically polymerizable compound. A photocurable adhesive composition, a photocurable adhesive sheet, and a joined body were obtained in the same manner as in Example 1 except that 30 parts of “EPR21” was used. The reaction rate of the epoxy group in the photocurable adhesive composition after irradiation with light was determined by the above method to be 83 mol%.

Comparative Example 2 In the preparation of a photocurable adhesive composition, a crosslinked NBR fine particle-dispersed epoxy resin was used without containing a naphthalene type epoxy resin “Epiclon HP-4032D” as a photocationically polymerizable compound. A photocurable adhesive composition, a photocurable adhesive sheet and a bonded body were obtained in the same manner as in Example 4 except that 30 parts of “EPR21” was used. In addition, the reaction rate of the epoxy group in the photocurable adhesive composition after irradiation with light was determined by the above method to be 80 mol%.

The performances (initial adhesive strength, normal adhesive strength, and water-resistant adhesive strength) of the seven types of joined bodies obtained in Examples 2 to 6 and Comparative Examples 1 and 2, and the seven types of photocurable adhesives The performance (storage stability) of the landing sheet was evaluated in the same manner as in Example 1. The results were as shown in Table 1.

[0116]

[Table 1]

As is clear from Table 1, the bonding of Examples 1 to 6 produced using the photocurable pressure-sensitive adhesive composition and the photocurable pressure-sensitive adhesive sheet of Examples 1 to 6 according to the present invention. The body is
It was excellent in all of initial adhesive strength, normal adhesive strength and water resistant adhesive strength, and exhibited extremely excellent balance performance. The photocurable pressure-sensitive adhesive sheets of Examples 1 to 6 were left for (a) one month in a dark place at 40 ° C., and (b) six months in a dark place at 23 ° C. In each case, there was no change in performance as compared with the initial performance, and the storage stability was excellent.

On the other hand, in the preparation of the photocurable pressure-sensitive adhesive composition, a photocationically polymerizable compound containing no naphthalene type epoxy resin, biphenyl type epoxy resin or fluorene type epoxy resin was used. The bonded bodies of Comparative Examples 1 and 2 produced using the photocurable adhesive composition and the photocurable adhesive sheet of Examples 1 and 2,
In each case, the normal adhesive strength and the water-resistant adhesive strength B were considerably low, and the water-resistant adhesive strength A was extremely low. this is,
When the epoxy resin is not contained in the photocationically polymerizable compound, it indicates that it is difficult to obtain a cured product exhibiting sufficient performance by only photocationic polymerization.

Example 7 In the preparation of a photocurable adhesive composition, 70 parts of a butyl acrylate resin (weight average molecular weight: 900,000) was used as an acrylic polymer, and a bisphenol A type epoxy resin was used as a photocationically polymerizable compound. (Trade name “Epicoat 828”, manufactured by Yuka Shell Epoxy Co., Ltd.) 25 parts and a flexible epoxy resin (trade name “BEO6
0E, 5 parts by Nippon Rika Co., Ltd .; 3 parts of alicyclic diepoxycarboxylate (trade name "Epoxy221", manufactured by UCC) as an alicyclic epoxy resin; trade name "ADEKAOPTO" as a cationic photopolymerization initiator Mer SP1
70 "(manufactured by Asahi Denka Kogyo Co., Ltd.) and ME as an organic solvent
K100 parts were uniformly stirred and mixed at a stirring speed of 3000 rpm using a homodisper type stirring mixer (trade name: “Homodisper L type”, manufactured by Tokushu Kika Kogyo Co., Ltd.) in an atmosphere of 23 ° C., and photocured. A type adhesive composition was prepared.

Example 8 In the preparation of the photocurable adhesive composition, 25 parts of bisphenol A type epoxy resin “Epicoat 828” and 5 parts of flexible epoxy resin “BEO60E” were used as the cationic photopolymerizable compound. Instead of crosslinked NBR fine particle dispersed epoxy resin (trade name "EP
R21 "(manufactured by Asahi Denka Kogyo KK) was used in the same manner as in Example 7 except that 30 parts of a photocurable adhesive composition was obtained.

Example 9 In the preparation of a photo-curable adhesive composition, a butyl acrylate / glycidyl acrylate = 95/5 (weight ratio) was used instead of 70 parts of a butyl acrylate resin as an acrylic polymer. A photocurable adhesive composition was obtained in the same manner as in Example 8, except that 70 parts of a polymer resin (weight average molecular weight: 900,000) was used.

(Comparative Examples 3, 4, and 5) In the preparation of the photocurable adhesive composition, an alicyclic epoxy resin "Epoxy"
221 "was not contained, and a photocurable adhesive composition was obtained in the same manner as in Examples 7, 8, and 9, respectively.

Using the six types of photocurable adhesive compositions obtained in Examples 7 to 9 and Comparative Examples 3 to 5, Example 1 was used.
In the same manner as in the case of 6, six types of photocurable adhesive sheets and joined bodies were obtained.

The performance (initial adhesive strength, normal-state adhesive strength, and water-resistant adhesive strength) of the six kinds of joined bodies obtained in Examples 7 to 9 and Comparative Examples 3 to 5 and the six kinds of light-curable adhesives The performance (storage stability) of the landing sheet was evaluated in the same manner as in Example 1. The results were as shown in Table 2.

[0125]

[Table 2]

As is apparent from Table 2, the bonding of Examples 7 to 9 produced using the photocurable adhesive compositions of Examples 7 to 9 and the photocurable adhesive sheets of the present invention. The body is
It was excellent in all of initial adhesive strength, normal adhesive strength and water resistant adhesive strength, and exhibited excellent balance performance. The photocurable pressure-sensitive adhesive sheets of Examples 7 to 9 were also left after (a) one month in a dark place at 40 ° C. for one month, and (b) six months in a dark place at 23 ° C. In each case, there was no change in performance as compared with the initial performance, and the storage stability was excellent.

On the other hand, in the preparation of the photocurable pressure-sensitive adhesive composition, the photocurable pressure-sensitive adhesive compositions and the photocurable pressure-sensitive adhesive compositions of Comparative Examples 3 to 5 which did not contain an alicyclic epoxy resin were used. The joined bodies of Comparative Examples 3 to 5 produced using the adhesive sheet are as follows:
In each case, the normal adhesive strength and the water-resistant adhesive strength B were slightly lower, and the water-resistant adhesive strength A was significantly lower. this is,
This indicates that when the photocurable adhesive composition does not contain an alicyclic epoxy resin, it is difficult to obtain a cured product exhibiting sufficient performance only by photocationic polymerization.

[0128]

As described above, the photocurable adhesive composition according to the present invention has excellent surface tackiness (tack), initial tackiness and good storage stability at room temperature before curing. And, after curing by light irradiation, it exhibits excellent adhesive strength, water resistance, heat resistance, etc., so it has excellent handling workability and simplicity like adhesives and excellent adhesive properties like adhesives. It is also suitably used for applications used under severe conditions such as adhesion between a glass epoxy substrate and a polyimide film.

Further, according to the bonding method of the present invention, a bonded body having excellent adhesive properties can be easily obtained with a short curing time with good workability.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J040 DB041 DE021 DF011 DF041 DF051 DF061 DF081 DG021 DH021 EC021 EC061 EC071 EC081 EC121 EC211 EC251 EC262 EC351 EH031 FA291 GA05 GA07 GA10 GA11 GA12 GA13 GA17 HDB13 HC14 HD14 LA02 LA05 LA06 LA07 LA08 MA10 NA20

Claims (6)

[Claims] 1. A photocurable adhesive composition comprising an acrylic polymer, a cationic photopolymerizable compound and a cationic photopolymerization initiator, wherein the cationic photopolymerizable compound is a naphthalene type epoxy resin. 20% by weight of at least one epoxy resin selected from the group consisting of biphenyl type epoxy resin and fluorene type epoxy resin
A photocurable pressure-sensitive adhesive composition characterized by being a cationic photopolymerizable compound contained above. 2. A photo-curable adhesive composition comprising an acrylic polymer, a cationic photopolymerizable compound, a cationic photopolymerization initiator and an alicyclic epoxy resin, wherein the acrylic polymer, the photopolymer A photocurable adhesive composition comprising 1 to 10 parts by weight of an alicyclic epoxy resin based on 100 parts by weight of a total of a cationically polymerizable compound and a cationic photopolymerization initiator. 3. The acrylic polymer is a copolymer of an acrylic monomer having an alkyl group having 2 to 20 carbon atoms and an epoxy group-containing acrylic monomer having at least one epoxy group in a molecule. The photocurable adhesive composition according to claim 1 or 2, wherein 4. An acrylic polymer obtained by photoradical polymerization of an acrylic monomer and a composition obtained by removing the acrylic polymer from the photocurable adhesive composition according to claim 1 or 2. The photocurable adhesive composition according to claim 1, wherein the composition is an obtained copolymer. 5. The photocurable adhesive according to claim 1, wherein the reaction rate of the epoxy group in the cured product cured by irradiation with light is 40 to 80 mol%. Adhesive composition. 6. The photocurable pressure-sensitive adhesive composition according to claim 1, applied to one or both of the joining members, and before or after joining the joining members. A method for joining a joining member, comprising a step of irradiating the adhesive composition with light to cause the above-mentioned adhesive composition to undergo cationic cationic polymerization and cure.