JP2022096750A - Adhesive composition, adhesive including the same, adhesive sheet, and laminate - Google Patents

Abstract

To provide an adhesive composition that can give an adhesive that has proper stickiness before curing; shows excellent adhesiveness after bonding members and heat-curing; and barely shows a decrease in adhesive force in a hygrothermal environment.SOLUTION: An adhesive composition contains an acrylic resin (A), an epoxy compound (B) that is liquid at 25°C, with an epoxy equivalent of 200 g/mol or more (excluding (A) and (C)), a silane coupling agent (C) and a curing agent for epoxy compounds (D). The content of the epoxy compound (B) is 5-100 pts.wt. relative to 100 pts.wt. of the acrylic resin.SELECTED DRAWING: None

Description

The present invention relates to a viscous adhesive composition, and more particularly to a viscous adhesive which has adhesiveness under normal conditions, is adhered to an adherend, and then is cured by heating to firmly adhere. The present invention relates to a pressure-sensitive adhesive layer, a pressure-sensitive adhesive sheet, and a laminated body, which have a small decrease in adhesive strength even when exposed to a high-temperature and high-humidity environment for a long time after curing.

Conventionally, liquid adhesives using epoxy compounds have been used for bonding metals and plastics. Recently, as a viscous adhesive that has both adhesive and adhesive properties, it has adhesiveness under normal conditions, and after being attached to an adherend, it is cured by heating and firmly adheres. A heat-curable pressure-sensitive adhesive composition using an acrylic resin, an epoxy resin, and an epoxy curing agent has also been proposed (see, for example, Patent Documents 1 and 2).
Further, for the purpose of suppressing deterioration of adhesion in a moist heat environment, a pressure-sensitive adhesive using a silane coupling agent for an acrylic resin has been proposed (for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 200-100806 Japanese Unexamined Patent Publication No. 2020-839898 Japanese Unexamined Patent Publication No. 2012-171991

However, in the disclosed techniques of Patent Documents 1 and 2, although the shear strength after curing is excellent, the performance (moisture heat resistance) of suppressing the decrease in the adhesive strength in a moist heat environment is inferior.
Further, even if the silane coupling agent of Patent Document 3 is simply combined with the adhesive adhesive described in Patent Documents 1 and 2, it is still not possible to suppress the change in the adhesive force before and after exposure to a moist heat environment.

Therefore, in the present invention, under such a background, it has an appropriate adhesiveness before curing, has excellent adhesive strength after the members are bonded and heat-cured, and further suppresses a decrease in adhesive strength in a moist heat environment. It is an object of the present invention to provide a viscous adhesive composition capable of obtaining a viscous adhesive having excellent performance.

However, as a result of diligent research in view of such circumstances, the present inventors have been able to add a specific amount of a liquid epoxy-based compound to the acrylic-based resin, so that even an adhesive at room temperature before curing is excellent. It has been found that it has adhesive performance and can improve the adhesion to the adherend (normal temperature transferability).
Furthermore, by using an epoxy-based compound having a relatively large epoxy equivalent, the flexibility after curing is improved, the polarity of the adhesive is prevented from becoming too high, and the effect of using a silane coupling agent is improved. Since it was possible to draw out to the maximum extent, it was found that an adhesive having excellent moisture and heat resistance could be obtained, and the present invention was completed.

That is, the gist of the present invention is an acrylic resin (A), an epoxy compound (B) liquid at 25 ° C. having an epoxy equivalent of 200 g / mol or more (excluding (A) and (C)), and a silane coupling. A viscous adhesive composition containing an agent (C) and a curing agent (D) for an epoxy-based compound, wherein the content ratio of the epoxy-based compound (B) is 5 to 100 parts by weight with respect to 100 parts by weight of the acrylic resin. It is a viscous adhesive composition characterized by being a part.

The adhesive composition of the present invention can bond members at normal temperature and pressure before curing, has excellent room temperature transferability, adhesive strength after curing, and adhesive strength after exposure to a moist heat environment. , It is possible to obtain a viscous adhesive having excellent moisture and heat resistance.

Therefore, the adhesive layer of the present invention is used for various purposes such as building materials, in-vehicle parts, electronic parts, heat dissipation sheets, FPC manufacturing, semiconductor manufacturing processes, member encapsulation, and aviation parts. It can be suitably used for adhesive bonding applications such as sports equipment.

Hereinafter, the present invention will be described in detail.
In the present invention, "(meth) acrylic" means acrylic or methacrylic, "(meth) acryloyl" means acryloyl or methacrylic acid, and "(meth) acrylate" means acrylate or methacrylate. ..
The "acrylic resin" is a resin obtained by polymerizing a polymerization component containing at least one (meth) acrylate-based monomer.

In the present invention, the adhesive is an adhesive material that has adhesiveness (tack) at room temperature before curing and is cured by a trigger such as heat to increase the adhesive strength.

In the present invention, "curing" means curing of an epoxy-based compound by heating, and "cross-linking" described later means cross-linking of an acrylic resin, particularly cross-linking by reaction with a cross-linking agent.

The adhesive composition of the present invention comprises an acrylic resin (A), an epoxy-based compound (B) liquid at 25 ° C. having an epoxy equivalent of 200 g / mol or more, a silane coupling agent (C), and an epoxy-based compound. It contains a curing agent (D).
Hereinafter, the constituent components in this order will be described.

<Acrylic resin (A)>
The acrylic resin (A) is a resin obtained by polymerizing a polymerization component containing at least one (meth) acrylic monomer, and for example, the (meth) acrylic monomer is used as a main component, and in some cases, another Examples thereof include an acrylic resin obtained by polymerizing a polymerization component containing various polymerizable monomers.

The term "main component" of the (meth) acrylic monomer means that the (meth) acrylic monomer is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight, based on the entire polymerization component. It means that it contains the above.

Examples of the (meth) acrylic monomer include (meth) acrylic acid or a derivative thereof, (meth) acrylamide or a derivative thereof, and the like.

Examples of the derivative of the (meth) acrylic acid include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and 2-methyl-2-nitropropyl (meth). Acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3- Pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl Examples thereof include alkyl group-containing (meth) acrylates such as -2-propylpentyl (meth) acrylate and n-octadecyl (meth) acrylate.

Further, as another example of the above-mentioned (meth) acrylic acid derivative, for example, cycloalkyl (meth) acrylate such as cyclohexyl (meth) acrylate and cyclopentyl (meth) acrylate; aralkyl (meth) acrylate such as benzyl (meth) acrylate. Biphenyloxy structure-containing (meth) acrylates such as biphenyloxyethyl (meth) acrylates; 2-isobornyl (meth) acrylates, 2-norbornylmethyl (meth) acrylates, 5-norbornen-2-yl-methyl (meth) Acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, dicyclopentenyl (meth) acrylicate, dicyclopentenyloxyethyl (meth) acrylicate, dicyclopentanyl (meth) acrylicate, etc. Polycyclic (meth) acrylate; 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, methoxydiethylene glycol (meth) ) Acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, ethylcarbitol (meth) acrylate, phenoxyethyl (meth) acrylate, alkylphenoxypolyethylene glycol (meth) acrylate and other alkoxy groups or phenoxy groups ( Meta) acrylate; and the like.

Furthermore, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxy Hydroxyalkyl (meth) acrylates such as hexyl (meth) acrylates, 8-hydroxyoctyl (meth) acrylates, 10-hydroxydecyl (meth) acrylates, 12-hydroxylauryl (meth) acrylates, [4- (hydroxymethyl) cyclohexyl] Hydroxyl-containing (meth) acrylates such as methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate; glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, etc. Epoxy group-containing (meth) acrylate; 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl ( Halogen-containing (meth) acrylates such as meth) acrylates, octafluoropentyl (meth) acrylates, heptadecafluorodecyl (meth) acrylates, and 3-chloro-2-hydroxypropyl (meth) acrylates; dimethylaminoethyl (meth) acrylates and the like. Alkylaminoalkyl (meth) acrylates; 3-oxetanylmethyl (meth) acrylates, 3-methyl-oxetanylmethyl (meth) acrylates, 3-ethyl-oxetanylmethyl (meth) acrylates, 3-butyl-oxetanylmethyl (meth) acrylates. , 3-Hexyl-oxetane group-containing (meth) acrylates such as oxetanylmethyl (meth) acrylates; and the like.

Examples of the (meth) acrylamide derivative include N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N-isopropyl. N-alkyl group-containing (meth) acrylamide derivatives such as butyl (meth) acrylamide and N-hexyl (meth) acrylamide; N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylol-N-propane N-hydroxyalkyl group-containing (meth) acrylamide derivatives such as (meth) acrylamide; N-aminoalkyl group-containing (meth) acrylamide derivatives such as aminomethyl (meth) acrylamide and aminoethyl (meth) acrylamide; N-methoxymethyl ( N-alkoxy group-containing (meth) acrylamide derivatives such as meta) acrylamide and N-ethoxymethyl (meth) acrylamide; N-mercaptoalkyl group-containing (meth) acrylamide such as mercaptomethyl (meth) acrylamide and mercaptoethyl (meth) acrylamide. Derivatives: N-acrylamide morpholine, N-acryloylpiperidin, N-methacryloylpiperidin, N-acrylloylpyrrolidine and other heterocyclic-containing (meth) acrylamide derivatives: and the like.

These (meth) acrylic monomers may be used alone or in combination of two or more. Among these (meth) acrylic monomers, an alkyl group-containing (meth) acrylate is preferably used. The number of carbon atoms of the alkyl group in the alkyl group-containing (meth) acrylate is usually 1 to 20, preferably 1 to 12, and more preferably 1 to 8. It is preferable that the alkyl group has a small number of carbon atoms because it has excellent compatibility with the epoxy compound (B) described later. The alkyl group-containing (meth) acrylate is usually contained in an amount of 40% by weight or more, preferably 50% by weight or more, and more preferably 60% by weight or more based on the total polymerization component of the acrylic resin (A). The upper limit is usually 100% by weight.

Further, among these (meth) acrylic monomers, the monomer having an acryloyl group is preferably contained in an amount of 25% by weight or more, and 35% by weight or more, based on the total polymerization component of the acrylic resin (A). Is more preferable. The upper limit of the content of the monomer having an acryloyl group with respect to the entire polymerization component of the acrylic resin (A) is 100% by weight. By increasing the content ratio of the monomer having an acryloyl group, the transferability after forming the adhesive layer is excellent without impairing the adhesiveness before curing, and the handleability is improved.

As the monomer having such an acryloyl group, acrylic acid or a derivative thereof, acrylamide or a derivative thereof can be selected and used from the various (meth) acrylic monomers described above.

When an acrylic acid derivative is used as the monomer having an acryloyl group, for example, the glass transition temperature is high and the molecular weight of the acrylic resin (A) can be easily increased. Therefore, the glass transition temperature when the homopolymer is prepared is 0 ° C. The above acrylic acid derivatives are preferable. In particular, methyl acrylate is preferable in terms of polymerizability.

Further, considering the reactivity with the cross-linking agent (E) for an acrylic resin described later, an acrylate containing a hydroxyl group is suitable, for example, a hydroxyalkyl acrylate such as 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate. Is preferable. Further, it is also preferable to use acrylic acid for the same reason that the acrylate containing the hydroxyl group is suitable.

When an acrylamide derivative is used as the monomer having an acryloyl group, for example, dialkylacrylamide or N-acryloylmorpholine is suitable because the glass transition temperature is high and the compatibility with the epoxy compound (B) is excellent. .. In particular, by using an acrylamide derivative having a glass transition temperature of 0 ° C. or higher when the homopolymer is prepared, the glass transition temperature of the obtained acrylic resin (A) can be maintained high and the adhesion to the adherend can be improved. It is preferable in that it can be enhanced.

The polymerization component constituting the acrylic resin (A) may contain a polymerizable monomer other than the (meth) acrylic monomer (hereinafter referred to as “other polymerizable monomer”).
Examples of the other polymerizable monomer include unsaturated carboxylic acids such as crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide-N-glycolic acid, and silicic acid; Carboxylic acid vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl stearate, vinyl benzoate; monomers containing aromatic rings such as styrene and α-methylstyrene; acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, alkyl Examples thereof include vinyl ether, vinyl toluene, vinyl pyridine, vinylpyrrolidone, itaconic acid dialkyl ester, fumaric acid dialkyl ester, allyl alcohol, acrylic chloride, methyl vinyl ketone, allyltrimethylammonium chloride, dimethylallylvinyl ketone and the like. These may be used alone or in combination of two or more.

The polymerization component constituting the acrylic resin (A) preferably contains a functional group-containing monomer. As the functional group-containing monomer, it is preferable to contain at least one functional group-containing monomer selected from a hydroxyl group-containing monomer and a carboxy group-containing monomer. Of these, a functional group-containing monomer containing a (meth) acryloyl group is preferable. Among these, 2-hydroshikiethyl (meth) acrylate and (meth) acrylic acid are particularly preferable.

The content of the functional group-containing monomer is preferably 0.1 to 30% by weight, more preferably 1 to 25% by weight, based on the entire polymerization component constituting the acrylic resin (A). It is more preferably 3 to 20% by weight. If the amount of the functional group-containing monomer is too small, the cohesive force when the adhesive layer is formed tends to decrease, and the tackiness and reworkability tend to decrease. On the contrary, if the amount is too large, the storage stability of the adhesive layer tends to decrease and the pot life tends to be shortened.

The carboxyl group is preferably 0 to 3% by weight, preferably 0.01 to 2% by weight, and preferably 0.05 to 1% by weight.
If it is too large, the storage stability of the adhesive tends to decrease, and if it is too small, the adhesive strength after curing tends to decrease.

As a polymerization method of the acrylic resin (A), conventionally known methods such as solution radical polymerization, suspension polymerization, bulk polymerization and emulsion polymerization can be used. For example, a method of mixing or dropping a polymerization component and a polymerization initiator which are appropriately selected in an organic solvent and polymerizing under predetermined polymerization conditions can be mentioned. Among them, solution radical polymerization and massive polymerization are preferable and stable. Solution radical polymerization is particularly preferable in that an acrylic resin can be obtained.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane; esters such as ethyl acetate and butyl acetate; n-propyl alcohol and isopropyl alcohol. Such as aliphatic alcohols; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone; and the like. These organic solvents may be used alone or in combination of two or more.

Among these organic solvents, esters such as ethyl acetate and butyl acetate are used from the viewpoints of ease of polymerization reaction, effect of chain transfer, ease of drying when coating the adhesive composition, and safety. Kind: Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone are preferable.

Examples of the polymerization initiator used for such solution radical polymerization include 2,2'-azobisisobutyronitrile and 2,2'-azobis-2-methylbutyronitrile, which are ordinary radical polymerization initiators. , 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (methylpropionic acid) and other azo-based initiators; benzoyl peroxide, lauroyl peroxide, di-t-butyl peroxide, cumene. Organic radicals such as hydroperoxide; and the like; can be appropriately selected and used according to the monomer to be used. These polymerization initiators may be used alone or in combination of two or more.

In this way, the acrylic resin (A) used in the present invention can be obtained.

The weight average molecular weight (Mw) of the acrylic resin (A) is preferably 100,000 or more, more preferably 100,000 to 1,500,000, more preferably 150,000 to 1,000,000, and particularly preferably 200,000 to 80,000. It is 10,000. If the weight average molecular weight is too small, the toughness and cohesive force of the obtained adhesive layer tend to decrease, and the adhesive performance and reworkability before curing tend to decrease. Further, if the weight average molecular weight is too large, the viscosity tends to be too high and the scaling tends to increase during polymerization, and the compatibility with the epoxy compound (B) and the handleability tend to decrease.

The dispersity [weight average molecular weight (Mw) / number average molecular weight (Mn)] of the acrylic resin (A) is preferably 10 or less, more preferably 7 or less. If the degree of dispersion is too high, the cohesive force tends to decrease. The lower limit of the degree of dispersion is usually 1.

The weight average molecular weight of the acrylic resin (A) is the weight average molecular weight converted to the standard polystyrene molecular weight, and is a high-speed liquid chromatograph (manufactured by Nippon Waters Co., Ltd., "Waters 2695 (main body)" and "Waters 2414 (detector)"). Column: Chromatography GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical number of stages: 10000 stages / piece, filler material: styrene-divinylbenzene copolymer, filling The agent particle size (10 μm) can be measured by connecting three in series, and the number average molecular weight can also be measured by the same method. The degree of dispersion can be obtained from the measured values of the weight average molecular weight and the number average molecular weight.

The glass transition temperature (Tg) of the acrylic resin (A) is preferably −50 ° C. or higher, more preferably −30 ° C. to 150 ° C., still more preferably 0 to 100 ° C., and particularly preferably 10 to 80 ° C. Is. If the glass transition temperature is too low, the adhesive strength after curing tends to decrease, and if it is too high, the tack before curing tends to decrease.

Ｔｇ：重合体のガラス転移温度（Ｋ）
Ｔga：モノマーＡのホモポリマーのガラス転移温度（Ｋ） Ｗａ：モノマーＡの重量分率
Ｔgb：モノマーＢのホモポリマーのガラス転移温度（Ｋ） Ｗｂ：モノマーＢの重量分率
Ｔgn：モノマーＮのホモポリマーのガラス転移温度（Ｋ） Ｗｎ：モノマーＮの重量分率
（Ｗａ＋Ｗｂ＋・・・＋Ｗｎ＝１） The glass transition temperature is calculated from the following Fox formula.

Tg: Polymer glass transition temperature (K)
Tga: Monomer A homopolymer glass transition temperature (K) Wa: Monomer A weight fraction Tgb: Monomer B homopolymer glass transition temperature (K) Wb: Monomer B weight fraction Tgn: Monomer N homo Polymer glass transition temperature (K) Wn: Weight fraction of monomer N (Wa + Wb + ... + Wn = 1)

That is, it is a value calculated by applying the glass transition temperature and the weight fraction when homopolymers of the respective monomers constituting the acrylic resin are applied to the Fox formula.
The glass transition temperature when the monomer constituting the acrylic resin is homopolymer is usually measured by a differential scanning calorimeter (DSC), and is based on JIS K7121-1987 and JIS K6240. It can be measured by the method.

The refractive index of the acrylic resin (A) is usually 1.440 to 1.600. It is preferable to reduce the difference in the refractive index from the members to be laminated because the light loss at the interface of the members is small.

The refractive index is a value obtained by measuring the thinned acrylic resin (A) with a NaD line at 23 ° C. using a refractive index measuring device (“Abbe Refractometer 1T” manufactured by Atago Co., Ltd.).

<Epoxy compound (B) liquid at 25 ° C with an epoxy equivalent of 200 g / mol or more>
The epoxy compound (B) used in the present invention is a compound having one or more epoxy groups in the molecule. However, the acrylic resin (A) and the silane coupling agent (C) are excluded.
The epoxy compound (B) used in the present invention needs to have an epoxy equivalent of 200 g / mol or more and be liquid at 25 ° C.
In the present invention, the liquid refers to a state in which there is fluidity at 25 ° C.

The epoxy equivalent is 200 g / mol or more, preferably 210 to 10000 g / mol, particularly preferably 250 to 5000 g / mol, further preferably 300 to 2000 g / mol, and particularly preferably 400 to 1000 g / mol. It is mol. If the epoxy equivalent is too low, the adhesiveness tends to decrease when exposed to a high temperature and high humidity environment for a long time after curing, and if the epoxy equivalent is too high, the adhesive strength after curing tends to decrease.

In the present invention, the weight average molecular weight of the epoxy compound (B) is preferably 300 to 5000, more preferably 350 to 4000, and particularly preferably 400 to 2000. If the molecular weight is too small, it volatilizes during heat curing and tends to generate bubbles and the reworkability tends to decrease. If it is too large, the viscosity tends to increase and the tackiness when the adhesive layer is formed decreases. Tend to do.

Further, the epoxy compound (B) has one or more epoxy groups in one molecule, and the number of epoxy groups is preferably 2 or more, more preferably 2 to 6. If the number of epoxy groups is too large, the heat resistance to moisture tends to decrease.

Specific examples of the epoxy compound (B) include: EXA-4850-150, EXA-4850-1000, TSR-960 manufactured by DIC; JER YX-7700, JER YX-7400, JER871 manufactured by Mitsubishi Chemical Corporation. JER890, YX8034, YX7105; manufactured by ADEKA Corporation: EP-4100TX, EP-5100-75X, EP-4000, EP-7001, EPU-6, EPR-2000, ED-502 and the like.

In the present invention, the content of the epoxy-based compound (B) needs to be 5 to 100 parts by weight, more preferably 7.5 to 80 parts by weight, based on 100 parts by weight of the acrylic resin (A). It is by weight, particularly preferably 10 to 60 parts by weight, and even more preferably 10 to 50 parts by weight. If the content of the epoxy compound (B) with respect to the acrylic resin (A) is too small, the tackiness and adhesive strength of the adhesive layer before curing tend to decrease, and if it is too large, the adhesive layer of the adhesive layer tends to have a reduced content. Storage stability tends to decrease. Further, even if the content is too high or too low, the adhesiveness tends to decrease when exposed to a high temperature and high humidity environment for a long time after curing.

In the present invention, a known epoxy compound (B') generally used for adhesive applications other than the epoxy compound (B) which is liquid at 25 ° C. and has an epoxy equivalent of 200 g / mol or more can be used in combination. ..

In the present invention, the content ratio of the epoxy compound (B') other than the epoxy compound (B) is preferably 50 parts by weight or less, particularly 25 parts by weight, based on 100 parts by weight of the epoxy compound (B) in terms of moisture and heat resistance. It is preferably parts by weight or less, and more preferably 10 parts by weight or less.

Examples of the epoxy compound (B') include a monofunctional epoxy compound having one epoxy group in the molecule and a polyfunctional epoxy compound having two or more epoxy groups. These compounds may be used alone or in combination of two or more.

Examples of the monofunctional epoxy-based compound include alkyl glycidyl ether, alkoxy glycidyl ether, phenol glycidyl ether, EO (ethylene oxide) modified phenol glycidyl ether, and allyl glycidyl ether.

Among the above polyfunctional epoxy compounds, bifunctional epoxy compounds having two epoxy groups include, for example, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, and diethylene glycol di. Glycyzyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, diglycidyl terephthalate, diglycidyl-o-phthalate, diglycidyl resorcinol ether, bisphenol A type diglycidyl compound and its hydrogenated product, bisphenol F type diglycidyl compound and its Examples thereof include hydrogenated products, biphenyl-type diglycidyl compounds and derivatives thereof.

Examples of the polyfunctional epoxy compound having three or more epoxy groups include trifunctional epoxy compounds such as glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate and derivatives thereof, and pentaerythritol triglycidyl ether; Tetrafunctional epoxy compounds such as pentaerythritol tetraglycidyl ether, diglycerol tetraglycidyl ether, ditrimethylol propanetetraglycidyl ether; polyglycerol pentaglycidyl ether, pentaeristol pentaglycidyl ether, dipentaeristol pentaglycidyl ether and the like. Epoxy compounds; sorbitol hexaglycidyl ethers: hexafunctional epoxy compounds such as dipentaeristol hexaglycidyl ethers; polyglycidyl ethers, phenol novolac type epoxy compounds, cresol novolac type epoxy compounds; and the like.

<Silane coupling agent (C)>
The silane coupling agent used in the present invention is a general term for silane compounds having an alkoxysilyl group and other functional groups.
Examples of other functional groups include an amino group, an epoxy group, a mercapto group, an acid anhydride group, a carboxyl group, a hydroxyl group, a vinyl group, a (meth) acryloyl group, an isocyanate group and the like. Among these, an epoxy group and a mercapto group are preferable because they have a high interaction with an acrylic resin, and a mercapto group is more preferable because they have a high adhesion to a metal.

The silane coupling agent (C) may be a monomer type or an oligomer type in which a part of the silane coupling agent (C) is hydrolyzed and condensed. Among these, an oligomer type and a silane coupling agent having a molecular weight of 500 or more are preferable because they have less volatilization during drying and thermosetting, and are less likely to generate bubbles in the adhesive layer and have good moisture and heat resistance.

The content of the silane coupling agent (C) used in the present invention is preferably 0.01 to 3 parts by weight, particularly 0.05 to 2, 0.1 to 100 parts by weight with respect to 100 parts by weight of the acrylic resin (A). 1.5 parts by weight is preferable. If it is too small, the moisture and heat resistance tends to decrease, and if it is too large, the adhesive strength immediately after curing tends to decrease.

<Curing agent for epoxy compounds (D)>
The curing agent (D) for an epoxy-based compound used in the present invention is a compound used as a curing agent for the epoxy-based compound (B) and having a functional group capable of reacting with an epoxy group.
Examples of the curing agent (D) for an epoxy-based compound include amines, polyamides, imidazoles, polyvinylcaptan curing agents, acid anhydrides, and the like. These may be used alone or in combination of two or more. Among the above-mentioned curing agents for epoxy compounds (D), dicyandiamide and organic acid hydrazide, which are amine compounds, are preferable in terms of excellent storage stability and curability when used as a viscous adhesive, and organic acids are preferable. Among the hydrazides, adipic acid dihydrazide and sebacic acid dihydrazide are particularly preferable because they have an excellent curing rate.

Examples of the curing agent (D) for epoxy-based compounds include liquid and solid ones, and among them, in terms of storage stability when used as a viscous adhesive and in terms of pot life of the viscous adhesive composition. It is preferably a solid, and more preferably a powder in that the coating film becomes smooth and the adhesive area with the member increases when the coating film is cured, and the adhesive strength after curing is increased. Further, it is preferable that the powder is contained in the pressure-sensitive adhesive in a dispersed state. When a powder is used as the curing agent (D) for an epoxy-based compound, the particle size of the powder should be 1.2 times or less of the film thickness at the time of forming the adhesive layer. It is preferable to set it to 1, and it is more preferable that it is 1 times or less.

The content ratio of the curing agent (D) for an epoxy-based compound may be 1 to 100 parts by weight with respect to a total of 100 parts by weight of the epoxy-based compound (B) and (B') used as needed. Above all, it is more preferably 3 to 80 parts by weight, and particularly preferably 5 to 50 parts by weight.
Alternatively, the functional group amount (mol) of the epoxy compound curing agent (D) is 0.5 to 2 times the total epoxy group amount (mol) of the epoxy compound compounds (B) and (B'). Is preferable, and 0.6 times to 1.5 times is particularly preferable, and further 0.8 times to 1.2 times is preferable.
If the content ratio of the curing agent (D) for an epoxy-based compound to the epoxy-based compound (B) is too smaller than the above range, the curing speed tends to be slow or the curing temperature tends to be high. If it is too much, the strength of the coating film after curing tends to decrease, and the storage stability when used as an adhesive tends to decrease.

<Crosslinking agent for acrylic resin (E)>
The adhesive composition of the present invention contains the above-mentioned acrylic resin (A), epoxy-based compound (B), silane coupling agent (C), and curing agent (D) for epoxy-based compounds. However, it is preferable to further contain a cross-linking agent (E) for an acrylic resin (hereinafter, may be abbreviated as a cross-linking agent (E)) that cross-links the acrylic resin (A). By containing the cross-linking agent (E), the adhesive composition can be cross-linked, which is preferable in that the cohesive force of the adhesive is enhanced and the reworkability is improved. The acrylic resin (A) is also crosslinked by the epoxy compound (B), but the crosslinking agent (E) in the present invention is an epoxy compound (B) in that the acrylic resin is crosslinked before thermosetting. ) Is not included.

As the cross-linking agent (E) for acrylic resin, a known cross-linking agent can be used. Among them, an isocyanate-based cross-linking agent is preferable.
These cross-linking agents (E) may be used alone or in combination of two or more.

Examples of the isocyanate-based cross-linking agent include tolylene diisocyanate compounds such as 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate; 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, and tetra. Xylylene diisocyanate compounds such as methyl xylylene diisocyanate; aromatic isocyanate compounds such as 1,5-naphthalenedi isocyanate and triphenylmethane triisocyanate; hexamethylene diisocyanate, pentamethylene diisocyanate, isophorone diisocyanate, and these isocyanate-based compounds. Examples thereof include an adduct form with a polyol compound such as trimethylolpropane, a buretto form and an isocyanurate form of these polyisocyanate compounds.

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

Examples of the melamine-based cross-linking agent include hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, hexapentyloxymethyl melamine, hexahexyl oxymethyl melamine, and melamine resin.

Examples of the aldehyde-based cross-linking agent include glioxal, malondialdehyde, succindialdehyde, maleindialdehyde, glutardaldehyde, formaldehyde, acetaldehyde, and benzaldehyde.

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

The content of the cross-linking agent (E) used in the present invention is preferably 0 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, particularly, with respect to 100 parts by weight of the acrylic resin (A). It is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight. If the content of the cross-linking agent (E) is too large, the tack when forming the adhesive layer tends to decrease, and if it is too small, the adhesive layer is thermally decomposed when exposed to a high temperature. Deterioration is likely to occur.

<Arbitrary ingredient>
In the present invention, in addition to the above components, as optional components, for example, conductive agents such as carbon and metal; inorganic fillers such as metal particles and glass particles; urethane resin, rosin, rosin ester, hydrogenated rosin ester, and phenol. Adhesive-imparting agents such as resins, aliphatic petroleum resins, alicyclic petroleum resins, styrene resins; fillers; antioxidants; UV absorbers; ionic compounds, peroxides, esterification catalysts, etc. Various additives such as an agent; a cross-linking retarder such as acetylacetone; and the like can also be contained. These may be used alone or in combination of two or more.

In addition to the above optional components, the adhesive composition of the present invention contains impurities and the like contained in the raw materials for producing the constituent components of the adhesive composition to the extent that the effects of the present invention are not impaired. You may be doing it.

The adhesive composition of the present invention comprises an acrylic resin (A), an epoxy compound (B), a silane coupling agent (C), a curing agent for epoxy compounds (D), and, if necessary, acrylic. It can be obtained by mixing a cross-linking agent (E) for a system resin and other arbitrary components.
The method for mixing these components is not particularly limited, and various methods such as a method of mixing each component in a batch, a method of mixing an arbitrary component, and then a method of mixing the remaining components in a batch or sequentially. Can be adopted.

<Adhesive composition>
The adhesive composition of the present invention comprises the above acrylic resin (A), epoxy compound (B) and silane coupling agent (C), curing agent for epoxy compound (D), and if necessary, a cross-linking agent. It can be obtained by mixing (E) and other components.

The method for mixing these components is not particularly limited, and various methods such as a method of mixing each component in a batch, a method of mixing an arbitrary component, and then a method of mixing the remaining components in a batch or sequentially. Can be adopted.

[Adhesive, adhesive sheet, and laminate]
The adhesive composition of the present invention can be made into an adhesive by drying when a solvent is contained. Further, by laminating and forming the adhesive layer containing the adhesive on a substrate such as a plastic film, it is possible to obtain an adhesive sheet having a laminated structure of the substrate / adhesive layer. can. Further, by laminating this adhesive layer on the adherend, it is possible to obtain a laminated body having a laminated structure of the adherend / adhesive layer. In the following, the base material and the adherend are collectively referred to as "members".

The adhesive sheet includes a substrate-less double-sided adhesive in which a separator (release sheet) is laminated on both sides of the adhesive layer in addition to the adhesive sheet in which the adhesive layer is laminated on the substrate. There is an adhesive sheet, and a double-sided adhesive sheet is preferable in terms of ease of handling.

As a method for producing the adhesive sheet, for example, the adhesive composition can be applied on a base material and dried. When the cross-linking agent (E) is used, a separator is attached to the adhesive layer after drying, and aging is performed at room temperature (in a state where the epoxy compound is not heated) and in a heated state where the epoxy compound is not cured. A method of performing an aging process by at least one of the above can be mentioned. The adhesive composition is applied to the separator, dried, and then bonded to the separator with another separator having a different peeling force, and an aging treatment is performed to achieve double-sided adhesive adhesion without a base material. Sheets can be manufactured.

The above-mentioned aging treatment is performed in order to chemically crosslink the acrylic resin (A) and the crosslinking agent (E) when the crosslinking agent (E) is used to develop an appropriate cohesive force in the adhesive. It is a treatment, and as aging conditions, for example, the temperature is usually room temperature (20 ± 10 ° C.) to 40 ° C., the time is usually 1 to 30 days, and specifically, for example, 1 to 20 at 23 ° C. Conditions such as 1 to 7 days at 40 ° C. for one day can be mentioned.
When the cross-linking agent (E) is not used, the aging treatment is not always necessary.

When applying the adhesive composition, it is preferable to dilute the adhesive composition with a solvent and apply the adhesive composition, and the solid content concentration is preferably 5 to 65% by weight, more preferably 20. It is ~ 55% by weight.
The solvent is not particularly limited as long as it dissolves or disperses the adhesive composition. For example, ester solvents such as methyl acetate, ethyl acetate, methyl acetoacetate, ethyl acetoacetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; aromatic solvents such as toluene and xylene; methanol, ethanol and propyl alcohol. Etc. Alcohol-based solvent; etc. can be used. Among these, ethyl acetate is preferably used in terms of solubility, drying property, price and the like.

The viscosity of the diluted adhesive composition is preferably 500 to 30,000 mPa · s / 25 ° C, more preferably 1000 to 10000 mPa · s / 25 ° C. If the viscosity is too low, when a component having a heavy specific gravity is used, the component tends to settle, and the concentration of the component in the adhesive composition tends to be non-uniform.

Examples of the coating method of the adhesive composition include roll coating, die coating, gravure coating, comma coating, screen printing and the like.

The thickness of the adhesive layer in the adhesive sheet is preferably 5 to 250 μm, more preferably 25 to 200 μm, and even more preferably 50 to 175 μm. If the adhesive layer is too thin, the thickness accuracy tends to decrease or the adhesive strength tends to be low. If the adhesive layer is too thick, the adhesive sheet is rolled. The adhesive layer tends to stick out from the edges and contaminate the roll.

The gel fraction of the adhesive layer is preferably 0% to 99% or less, more preferably 20% or more to 95% or less, and further, from the viewpoint of adhesion to the member, reworkability, and adhesiveness before curing. It is preferably 30% or more and 80% or less. If the gel content of the adhesive layer is too high, sufficient adhesion between the adhesive layer and the interface of the member cannot be obtained when the adhesive sheet is attached to the member, and the adhesive strength after curing is increased. Tends to decline. The lower limit of the gel fraction is usually 0% by weight.

The gel fraction is a measure of the degree of cross-linking (curing degree), and is calculated by, for example, the following method. First, the adhesive is collected by picking from the adhesive sheet in which the adhesive layer is laminated on the surface of the base material, and the adhesive is wrapped in a 200 mesh SUS wire mesh and heated to 23 ° C. Immerse in prepared ethyl acetate for 24 hours. The weights of the adhesive layer before and after the immersion in ethyl acetate are measured, and the difference between the two weights is taken as the weight of the insoluble adhesive component remaining in the wire mesh. The weight percentage of the insoluble adhesive component remaining in the wire mesh with respect to the weight of the adhesive layer before the immersion in ethyl acetate is defined as the gel fraction.

In the present invention, since the adhesive has a function of being cured by heating at a predetermined temperature, the adhesive force of the adhesive layer in the adhesive sheet is increased, and the adhesive sheet becomes an adherend. Stick.
The heating temperature for curing the adhesive is preferably 100 to 250 ° C, more preferably 120 to 200 ° C, and even more preferably 130 to 185 ° C. If the temperature is too low, the curing time tends to be long and the workability tends to decrease, and if the temperature is too high, the epoxy compound (B) tends to volatilize or ignite. The heating time is preferably 5 to 240 minutes, more preferably 30 to 180 minutes, and even more preferably 45 to 120 minutes. If the time is too short, the curing tends to be insufficient and the adhesive strength tends to decrease, and if it is too long, the workability tends to decrease and the members to be bonded tend to deteriorate due to heat.

The adhesive sheet having the adhesive layer laminated on the surface of the separator can be easily adhered by simply peeling off the separator and adhering the adhesive layer to the target adherend surface. Since the adhesive layer can be transferred, the work efficiency is very good.

Further, a laminated body obtained by laminating other members via the adhesive layer, that is, a laminated body having a laminated structure of an adherend / adhesive layer / other members, is an adhesive. Since the layer has high adhesiveness before curing and exhibits high adhesive strength after curing, it is difficult for other members to easily shift or peel off from the adherend. Therefore, by using the adhesive adhesive of the present invention, a laminate having high adhesive reliability and excellent appearance can be obtained.

The adhesive composition of the present invention can be bonded to a member from a separator at room temperature before curing (transferability), has excellent coating film appearance and reworkability, and is resistant to adherends after curing. It is possible to form a viscous adhesive having excellent adhesiveness and also excellent moisture and heat resistance.
Therefore, the adhesive composition of the present invention is used for various adhesive applications such as building materials, in-vehicle parts, electronic parts, semiconductor manufacturing processes, member encapsulation, aviation parts, and sports equipment. It can be suitably used for various adhesive applications such as.

In the present invention, it is particularly useful for applications of flexible printed wiring boards (FPCs), for example, for bonding FPCs and reinforcing plates, and for bonding FPCs and reinforcing plates, sticking to an adherend. It is not necessary to use heat sticking (heat lami) for sticking, it can be stuck to the adherend at room temperature, it has good reworkability, and it has excellent adhesion reliability after heat curing, which is very good. It is useful.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the example, "part" and "%" mean the weight standard.
In addition, the weight average molecular weight, dispersity, glass transition temperature, and other physical properties of the acrylic resin in the following examples were measured according to the above-mentioned methods.
First, the following ingredients were prepared prior to the examples.

<Acrylic resin (A)>
[Preparation of acrylic resin (A-1)]
80 parts of ethyl acetate, 6 parts of methyl ethyl ketone, and 0 azobisisobutyronitrile (AIBN) as a polymerization initiator in a 4-necked round bottom flask equipped with a reflux cooler, a stirrer, a nitrogen gas inlet and a thermometer. .036 parts charged and heated to reach the boiling point, then 40 parts of methyl acrylate (MA), 10 parts of methyl methacrylate (MMA), 44.9 parts of n-butyl methacrylate, 2-hydroxyethyl acrylate (2HEA). A mixed solution of 5 parts, 0.1 part of acrylic acid (AAc), 4 parts of ethyl acetate and 0.036 part of the polymerization initiator (AIBN) was added dropwise over 2 hours while maintaining the boiling state. Then, while continuing the reaction, 0.05 part of the polymerization initiator (AIBN) was added twice, the reaction was carried out for 7 hours, and then the mixture was diluted to obtain an acrylic resin (A-1) solution (solid content concentration 42. 2%, viscosity 5200 mPa · s / 25 ° C., acrylic resin (A-1): weight average molecular weight (Mw 246,000, dispersity (Mw / Mn) 2.4, glass transition temperature (Tg) 19.7 ° C. ) Was obtained.

[Preparation of acrylic resin (A-2)]
88.8 parts of ethyl acetate, 1.3 parts of methyl ethyl ketone, and azobisisobutyronitrile (azobisisobutyronitrile) as a polymerization initiator in a 4-necked round bottom flask equipped with a reflux cooler, a stirrer, a nitrogen gas inlet and a thermometer. After 0.025 parts of AIBN) is charged and heated to reach the boiling point, 76.8 parts of n-butyl acrylate (BA), 20 parts of methyl methacrylate (MA), and 2-hydroxyethyl acrylate (2HEA) 3 A mixed solution of 0.2 parts of acrylic acid (AAc), 5 parts of ethyl acetate, and 0.038 parts of the polymerization initiator (AIBN) was added dropwise over 2 hours while maintaining the boiling state. Then, while continuing the reaction, 0.038 part of the polymerization initiator (AIBN) and 0.038 part of azobisdimethylvaleronitrile (ADVN) were sequentially added, reacted for 7 hours, diluted, and acrylic resin. (A-2) Solution (solid content concentration 39.6%, viscosity 7000 mPa · s / 25 ° C., acrylic resin (A-2): weight average molecular weight (Mw 700,000, dispersion 4.7 (Mw / Mn)) , Glass transition temperature (Tg) −44 ° C.) was obtained.

<Epoxy compound (B)>
The following epoxy compounds (B) were prepared.
(B-1): jER YX7400 (manufactured by Mitsubishi Chemical Corporation) Viscosity 200 mPa · s at 25 ° C., epoxy equivalent 440 g / mol
(B'-1): Denacol EX-321 (manufactured by Nagase ChemteX Corporation), viscosity at 25 ° C., 140 mPa · s, epoxy equivalent 140 g / mol

<Silane coupling agent (C)>
The following were prepared as the silane coupling agent (C).
(C-1): E-freeJ189 (Mercapto-based silane coupling agent, manufactured by Momentive)
(C-2): X-41-1810 (mercapto-based silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd.)
(C-3): KR-516 (epoxy silane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd.)

<Curing agent for epoxy compounds (D)>
The following were prepared as the curing agent (D) for the epoxy compound.
(D-1): Adipic acid dihydrazide (ADH-S: manufactured by Otsuka Chemical Co., Ltd.)

<Crosslinking agent for acrylic resin (E)>
The following materials were prepared as the cross-linking agent (E) for the acrylic resin.
(E-1): Coronate L55E (manufactured by Tosoh Corporation: trimethylolpropane and tolylene diisocyanate adduct)

<Examples 1 to 4, Comparative Examples 1 to 5>
The above components were blended according to Table 1 below, and the solid content concentration was adjusted to the range of 30 to 60% using ethyl acetate to obtain a viscous adhesive composition.

From the obtained adhesive composition, an adhesive sheet was prepared according to the procedure shown below. Then, the evaluation was performed using this adhesive sheet.
The evaluation methods and evaluation criteria for each item are as follows. In addition, these results are also shown in Table 1 below.

<Making an adhesive sheet>
The adhesive composition was applied to a heavy-release silicon separator (manufactured by Mitsui Chemicals Tohcello Co., Ltd., "SPPET03 38BU") having a thickness of 38 μm using a comma coater so that the thickness after drying was 50 μm. It was dried for 3 minutes to form a viscous adhesive layer. A lightly peelable silicon separator (manufactured by Mitsui Chemicals Tohcello Co., Ltd., "SPPET01 38BU") having a thickness of 38 μm was attached to the surface of the adhesive layer, and then aged at 40 ° C. for 3 days to prepare an adhesive sheet (adhesive sheet). Light peeling silicon separator / adhesive layer / heavy peeling silicon separator laminate).

[Room temperature transferability]
The light peeling silicon separator of the adhesive sheet produced above is peeled off, and the adhesive layer side is bonded to a polyimide film (Kapton 200H: manufactured by Toray DuPont) at room temperature, and the adhesive sheet with a film substrate is attached. Got It was visually confirmed whether or not the adhesive layer was transferred to the polyimide film when the heavy-release silicon separator was peeled off from the obtained adhesive sheet with a film substrate, and evaluated according to the following criteria.
(Evaluation criteria)
○ ・ ・ ・ Transferred × ・ ・ ・ Not transferred

[Adhesive strength and reworkability before thermosetting]
The light peeling silicon separator of the adhesive sheet produced above is peeled off, and the adhesive layer side is bonded to a polyimide film (Kapton 200H: manufactured by Toray DuPont) at room temperature, and the adhesive sheet with a film substrate is attached. Got The heavy-release silicon separator is peeled off from the obtained adhesive sheet with a film substrate, and the adhesive layer side is attached to a SUS304-BA plate by reciprocating a 1 kg roller twice at room temperature, and after 30 minutes, the film base is attached. The adhesive strength (unit: N / 25 mm) of the adhesive sheet with a material was measured using AUTO Graph AG-X Plus (manufactured by Shimadzu Corporation) under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 °. At that time, it was confirmed whether the adhesive adhesive remained on the surface of the SUS304-BA plate (reworkability).

[Initial adhesive strength after thermosetting]
The light peeling silicon separator of the adhesive sheet produced above is peeled off, and the adhesive layer side is bonded to a polyimide film (Kapton 200H: manufactured by Toray DuPont) at room temperature, and the adhesive sheet with a film substrate is attached. Got After cutting out the obtained adhesive sheet with a film substrate to a width of 25 mm, the heavy-release silicon separator is peeled off, and the adhesive layer side is attached to a SUS304-BA plate by reciprocating a 1 kg roller twice at room temperature. After being attached, it was heat-cured at 160 ° C. for 1 hour. After that, the temperature was adjusted in a 23 ° C. × 50% RH environment, and the mixture was peeled off using AUTO Graph AG-X Plus (manufactured by Shimadzu Corporation) under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 °, and after heat curing. The initial adhesive strength was measured.

[Adhesive strength after wet heat test]
The test piece (SUS304-BA / adhesive layer / polyimide film) obtained in the same manner as the initial adhesive strength after heat curing was allowed to stand in an 85 ° C. × 85% RH environment for 500 hours, and then the initial adhesive strength was obtained. The adhesive strength after the wet heat test was measured by the same test method, and the maintenance rate of the adhesive strength was calculated.

(Evaluation criteria)
Maintenance rate: Initial adhesive strength / adhesive strength after wet heat test x 100
◎ ・ ・ 80% or more 〇 ・ ・ 50% or more × ・ ・ Less than 50%

From the above results, in Examples 1 to 5 using the adhesive composition containing the epoxy compound (B) and the silane coupling agent (C), the decrease in adhesive strength was small before and after the moist heat test, and the durability was high. You can see that it is excellent in sex.
On the other hand, Comparative Examples 1 and 2 using the pressure-sensitive adhesive composition containing the epoxy compound (B) but not the silane coupling agent (C) are inferior in moist heat resistance and epoxy. In Comparative Examples 3 and 4 using the adhesive composition containing no system compound (B), the moisture resistance is low regardless of the presence or absence of the silane coupling agent, and a specific epoxy compound and the silane coupling agent should be used in combination. It is possible to obtain a viscous adhesive having excellent moisture and heat resistance.

The adhesive composition of the present invention has a tack before curing and has an appropriate adhesive strength, and after curing, it can form an adhesive having high adhesive strength and excellent moisture and heat resistance. Therefore, the adhesive composition of the present invention is used for various adhesive applications such as building materials, in-vehicle parts, electronic parts, semiconductor manufacturing processes, member encapsulation, aviation parts, and sports goods. It can be suitably used for various adhesive bonding applications such as, and is particularly useful for bonding an FPC and a reinforcing plate.

Claims (10)

Acrylic resin (A), epoxy equivalent of 200 g / mol or more, liquid epoxy compound (B) at 25 ° C. (excluding (A) and (C)), silane coupling agent (C), and It is a viscous adhesive composition containing a curing agent (D) for an epoxy-based compound, and is characterized in that the content ratio of the epoxy-based compound (B) is 5 to 100 parts by weight with respect to 100 parts by weight of the acrylic resin. Epoxy composition. The adhesive composition according to claim 1, wherein the acrylic resin (A) has a weight average molecular weight of 100,000 or more. The adhesive composition according to claim 1 or 2, wherein the epoxy compound (B) contains an epoxy-based compound having at least two or more epoxy groups. The viscosity according to any one of claims 1 to 3, wherein the content of the silane coupling agent (C) is 0.01 to 3 parts by weight with respect to 100 parts by weight of the acrylic resin. Adhesive composition. The adhesive composition according to any one of claims 1 to 4, wherein the curing agent (D) for an epoxy compound is a powder curing agent. The adhesive composition according to any one of claims 1 to 5, further comprising a cross-linking agent (E) for an acrylic resin. A viscous adhesive according to any one of claims 1 to 6, wherein the cohesive adhesive composition is crosslinked. The adhesive adhesive according to claim 7, wherein the adhesive is cured by heating at 100 to 250 ° C. A pressure-sensitive adhesive sheet comprising the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive according to claim 7. A laminated body, wherein the adhesive layer made of the adhesive according to claim 7 or 8 and another member are laminated.