KR20150005459A - Adhesive composition and adhesive sheet - Google Patents

Abstract

The present invention provides an adhesive composition and an adhesive sheet having visibility and adhesiveness. In order to achieve the purpose, the adhesive composition according to the present invention includes an acrylic polymer, a phenol resin, an epoxy resin, and a colorant; and contains 10 parts by weight or less of the colorant with regard to 100 parts by weight of the acrylic polymer.

Description

[0001] ADHESIVE COMPOSITION AND ADHESIVE SHEET [0002]

The present invention relates to an adhesive composition used for an adhesive and the like, and an adhesive sheet using the composition.

BACKGROUND OF THE INVENTION Flexible printed circuit boards (sometimes referred to as " FPC ") are widely used in electronic devices. In such an FPC, (1) a process of producing an FPC by laminating a conductive metal foil such as a copper foil or an aluminum foil on a heat resistant substrate such as a polyimide substrate or a polyamide substrate, or (2) An adhesive is used for bonding to a reinforcing plate such as a plate or a polyimide plate.

As an adhesive used for bonding the FPC, an elastomer / epoxy resin adhesive has been widely used. Further, as an adhesive for electronic equipment, an adhesive composed of an elastomer / phenol resin / crosslinking agent for phenol resin is known (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2010-65078

The adhesive may contain a coloring agent for the purpose of improving the visibility depending on the application. However, when a colorant is contained, the adhesive strength may decrease. Accordingly, an object of the present invention is to provide an adhesive composition and an adhesive sheet both of which have visibility and adhesive strength.

The adhesive composition according to the present invention contains an acrylic polymer, a phenol resin, an epoxy resin and a colorant, and contains 10 parts by weight or less of a colorant to 100 parts by weight of the acrylic polymer.

The adhesive composition according to the present invention preferably contains 5 to 20 parts by weight of the phenol resin (preferably a resol-type phenol resin) per 100 parts by weight of the acrylic polymer.

In the adhesive composition according to the present invention, it is preferable that the epoxy resin is contained in an amount of 5 to 20 parts by weight based on 100 parts by weight of the acrylic polymer.

In the adhesive composition according to the present invention, it is preferable that the coloring agent is a dye or a pigment.

The adhesive sheet according to the present invention is formed by any one of the above adhesive compositions. The adhesive sheet typically has an adhesive layer formed by using any one of the adhesive compositions.

The adhesive composition according to the present invention can provide an adhesive composition and an adhesive sheet both having good visibility and adhesive strength.

Hereinafter, the present invention will be described in detail.

The adhesive composition according to the present invention contains an acrylic polymer, a phenol resin, an epoxy resin, and a colorant.

In the present specification, " A to B " denoting a range means A to B, inclusive. The various physical properties exemplified in this specification refer to values measured by the methods described in the following examples, unless otherwise specified.

The term " main component " in the present specification means a component having the highest content ratio based on the weight of the composition, and usually means 50 to 100% by weight. In the present specification, the term " adhesive sheet " is a concept including a tape configuration, that is, an " adhesive tape ".

<Acrylic Polymer>

The acrylic polymer may be a polymer constituted (or formed) by using an acrylic monomer as an essential monomer component, and is not particularly limited. The acrylic polymer preferably contains (meth) acrylic acid C _{2 -14} alkyl ester (a) and cyano group-containing monomer (b) as a monomer component. In addition to the above (a) and (b), it is particularly preferable that the carboxyl group-containing monomer (c) is further used. (Meth) acrylic acid C _{2 -14} alkyl ester (a) in an amount of 50 to 85% by weight, the cyano group-containing monomer (b) in an amount of 10 to 45% by weight, and the carboxyl group-containing monomer (c) in a total amount of 0.1 To 7% by weight of the monomer component. As the monomer component, a monomer component other than the above may be used.

The (meth) acrylic acid C _{2 -14} alkyl ester (a) is not particularly limited as long as it is a (meth) acrylic acid alkyl ester having a straight-chain or branched alkyl group having 2 to 14 carbon atoms. (Meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s- (meth) acrylate, isopentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (Meth) acrylate, isodecyl (meth) acrylate, isodecyl (meth) acrylate, decyl (meth) acrylate, isodecyl ) And tetradecyl acrylate. Among them, (meth) acrylic acid alkyl ester having an alkyl group having 4 to 12 carbon atoms is suitable, and n-butyl acrylate can be suitably used. The (meth) acrylic acid C _{2 -14} alkyl ester (a) may be used singly or in combination of two or more.

The (meth) acrylic acid C _{2 -14} alkyl ester (a) is preferably used as a main component of the monomer component constituting the acrylic polymer. The proportion of the (meth) acrylic acid C _{2 -14} alkyl ester (a) is preferably 50 to 85% by weight, more preferably 60 to 75% by weight, based on the whole amount of the monomer components.

The cyano group-containing monomer (b) is not particularly limited as long as it is a monomer having a cyano group. For example, acrylonitrile, methacrylonitrile and the like can be mentioned, and acrylonitrile can be suitably used. The cyano group-containing monomer (b) may be used singly or in combination of two or more.

In the acrylic polymer, it is preferable to use the cyano group-containing monomer (b) in order to improve the heat resistance and the adhesiveness (flexibility). Therefore, the proportion of the cyano group-containing monomer (b) is preferably 10 to 45% by weight, more preferably 20 to 35% by weight, based on the whole amount of the monomer component. When the proportion of the cyano group-containing monomer (b) is within the above range, heat resistance and flexibility are more excellent.

The carboxyl group-containing monomer (c) is not particularly limited as long as it is a monomer having a carboxyl group. Examples thereof include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid and the like. In addition, acid anhydrides of these carboxyl group-containing monomers (for example, monomers containing an acid anhydride group such as maleic anhydride and itaconic anhydride) can also be used as the carboxyl group-containing monomer (c). As the carboxyl group-containing monomer (c), it is preferable to use acrylic acid, methacrylic acid or itaconic acid. The carboxyl group-containing monomer (c) may be used singly or in combination of two or more.

In the acrylic polymer, it is preferable to use the carboxyl group-containing monomer (c) in order to improve heat resistance and adhesiveness. Therefore, the proportion of the carboxyl group-containing monomer (c) is preferably from 0.1 to 7% by weight, more preferably from 0.5 to 6% by weight, based on the whole amount of the monomer component. When the proportion of the carboxyl group-containing monomer (c) is within the above range, flexibility is more excellent.

As the monomer component constituting the acrylic polymer, other monomer components (copolymerizable monomers) are used in addition to the (meth) acrylic acid C _{2 -14} alkyl ester (a), the cyano group-containing monomer (b) and the carboxyl group- good.

Such copolymerizable monomers include, for example, (meth) acrylates such as methyl (meth) acrylate; (Meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) (meth) acrylate, eicosyl acrylate, C _{15 - 20} alkyl esters; (Meth) acrylic acid cycloalkyl ester [(cyclohexyl (meth) acrylate], and non-aromatic ring-containing (meth) acrylic acid esters such as isobornyl (meth) acrylate; (Meth) acrylic acid aryl esters such as phenyl (meth) acrylate], (meth) acrylate aryloxyalkyl esters such as phenoxy ethyl acrylate and the like; (meth) acrylic acid arylalkyl esters such as [ Of aromatic ring containing (meth) acrylic acid esters; Epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate and methylglycidyl (meth) acrylate; Vinyl ester monomers such as vinyl acetate and vinyl propionate; Styrene-based monomers such as styrene and? -Methylstyrene; Hydroxyl group-containing monomers such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate; (Meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; (Meth) acrylic acid aminoalkyl monomers such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate and t-butylaminoethyl (meth) acrylate; Substituted amide monomers such as N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide and N-hydroxy (meth) Amide-based monomers such as amide-based monomers; Olefinic monomers such as ethylene, propylene, isoprene and butadiene; Vinyl ether-based monomers such as methyl vinyl ether; And the like.

Further, it is also possible to use, as the copolymerizable monomers, hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol Acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, (Meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, and divinylbenzene may be used.

The acrylic polymer can be produced by a publicly known polymerization method (for example, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, or a polymerization method by ultraviolet irradiation).

The polymerization initiator, chain transfer agent, emulsifier and the like which are used in polymerization of the acrylic polymer are not particularly limited and can be appropriately selected from publicly known and commonly used ones.

More specifically, examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'- Azobis (cyclohexane-1-carbonitrile), 2, 2'-azobis (2-methylbutyronitrile) Azobis (2,4,4-trimethylpentane), dimethyl-2,2'-azobis (2-methylpropionate), 2,2'-azobis {2- [1- Hydroxyethyl) -2-imidazolin-2-yl] propane} dihydrochloride; Benzoyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dicumyl peroxide, 1,1-bis (t- Peroxide-based polymerization initiators such as trimethylcyclohexane and 1,1-bis (t-butylperoxy) cyclododecane; And the like. The polymerization initiator may be used alone or in combination of two or more. The amount of the polymerization initiator to be used can be appropriately selected from the range of usual use amount.

Examples of the chain transfer agent include 2-mercaptoethanol, lauryl mercaptan, glycidylmercaptan, mercaptoacetic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, Styrene dimer and the like.

Examples of the emulsifier include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkylether sulfate, ammonium polyoxyethylene alkylphenylether sulfate, and sodium polyoxyethylene alkylphenylether sulfate; Nonionic emulsifiers such as polyoxyethylene alkyl ethers and polyoxyethylene alkyl phenyl ethers; And the like.

In solution polymerization various general solvents can be used. Examples of such a solvent include esters such as ethyl acetate and n-butyl acetate; Aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; Alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; Ketones such as methyl ethyl ketone and methyl isobutyl ketone; And the like. The solvent may be used singly or in combination of two or more.

The weight average molecular weight of the acrylic polymer is not particularly limited, but may be suitably selected from the range of, for example, 200,000 to 1,600,000 (preferably 300,000 to 1,400,000). The weight average molecular weight of the acrylic polymer can be controlled by the monomer concentration, the monomer dropping rate, etc. in addition to the kind of the polymerization initiator and the chain transfer agent, the amount of the polymerization initiator used, the temperature and time during polymerization. The weight average molecular weight of the acrylic polymer can be measured by, for example, a gel permeation chromatograph (GPC). The measurement conditions at that time are not particularly limited and can be appropriately selected from known measurement conditions.

<Phenolic resin>

The phenol resin is not particularly limited and may be appropriately selected from a resol-type phenol resin, a novolak-type phenol resin, various modified phenol resins (for example, an alkyl-modified phenol resin and the like) Among them, a resol-type phenol resin is preferable. The phenol resins may be used singly or in combination of two or more.

As the phenol resin, a commercially available phenol resin can be used. As the resol type phenol resin, for example, trade name "SUMILITE RESIN PR-51283" (manufactured by Sumitomo Bakelite Co., Ltd.) may be used. As the novolak type phenol resin, for example, trade name "Tamanor (758)" (manufactured by Arakawa Chemical Industries, Ltd.) may be used.

The phenolic resin is used for imparting thermosetting property and heat resistance. The blending ratio of the phenol resin is preferably 3 to 20 parts by weight (for example, 5 to 20 parts by weight) based on 100 parts by weight of the acrylic polymer. The mixing ratio of the phenol resin is more preferably 4 to 18 parts by weight, and still more preferably 6 to 15 parts by weight.

When the proportion of the phenol resin is within the above range, the thermosetting property and the heat resistance (strength of the adhesive layer) are more excellent.

&Lt; Epoxy resin &

As the epoxy resin, a resin generally used in the adhesive field can be used. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, glycidylamine type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, Naphthalene type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring containing epoxy resin, halogenated epoxy resin and the like can be used. Among them, bisphenol A type epoxy resin and glycidylamine type epoxy resin are suitably used. These may be used singly or in combination of two or more.

The blending amount of the epoxy resin is preferably 20 parts by weight or less, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the acrylic polymer. By setting the content to 20 parts by weight or less, it is possible to suppress the generation of bubbles and the deterioration of the adhesiveness when press curing.

<Colorant>

The colorant is not particularly limited, but conventionally known pigments or dyes can be used. Examples of the pigment include pigments such as zinc carbonate, zinc oxide, zinc sulfide, talc, kaolin, calcium carbonate, titanium oxide, silica, lithium fluoride, calcium fluoride, barium sulfate, alumina, zirconia, iron oxide, iron hydroxide, Inorganic pigments such as chromium oxide, chrome oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, chromium oxide, aluminum oxide, bronze powder, calcium phosphate, and phthalocyanine, azo, , Organic pigments such as perylene / perinone type, indigo / thioindigo type, isoindolinone type, azomethine type, dioxo type, quinacridone type, aniline black type, triphenylmethane type and carbon black type .

Examples of the dye include azo dyes, anthraquinone, quinonaphthalone, styryl, diphenylmethane, triphenylmethane, oxazine, triazine, xanthan, methane, azomethine, acridine, .

From the viewpoint of visibility, it is preferable to use a pigment or dye having a large color difference from an adherend. For example, when the adherend is a polyimide film, since the polyimide film is generally semitransparent yellow, a pigment or dye of a dark color such as black, blue, or green may be used.

The blending amount of the colorant is suitably 10 parts by weight or less, preferably 9 parts by weight or less, based on 100 parts by weight of the acrylic polymer. The lower limit of the blending amount of the coloring agent can be set so as to obtain desired visibility. Usually, the blending amount of the colorant relative to 100 parts by weight of the acrylic polymer is suitably 0.01 part by weight or more, preferably 0.03 parts by weight or more (for example, 0.05 part by weight or more).

A more preferable blending amount may vary depending on the type of the colorant. For example, in the case of using a pigment as a coloring agent, from the viewpoint of visibility, the blending amount relative to 100 parts by weight of the acrylic polymer is preferably 1 part by weight or more, more preferably 3 parts by weight or more. When a dye is used as the colorant, the blending amount relative to 100 parts by weight of the acrylic polymer may be 3 parts by weight or less, preferably 1 part by weight or less, and 0.8 parts by weight or less, 0.5 parts by weight or less).

It is preferable to select and adjust the colorant so that the volume resistivity of the adhesive layer or the adhesive sheet including the colorant is 1 x 10 &lt; ¹¹ &gt; (OMEGA .cm) or more. In particular, when colored with black, carbon black is generally used as a black pigment, but depending on the kind of carbon black, electrical resistance may be lowered. Therefore, it is preferable to select and adjust the pigment so that the volume resistivity of the adhesive layer or the adhesive sheet including the pigment is at least 1 x 10 &lt; ¹¹ &gt; (OMEGA .cm) or more.

&Lt; Adhesive composition >

In addition to the acrylic polymer, the phenolic resin, the epoxy resin and the colorant, the adhesive composition may contain additives such as antioxidants, fillers, ultraviolet absorbers, antioxidants, crosslinking agents, tackifiers, plasticizers, softeners, surfactants, antistatic agents, . The above adhesive composition can be produced by mixing these components.

The adhesive composition or the adhesive layer formed by the adhesive composition, the storage elastic modulus at 250 ℃ after curing at 150 ℃, for 3 hours, is preferred, more preferably not less than 1.0 × 10 ⁵ ㎩ is 1.0 × 10 ⁶ Pa or more. When the storage elastic modulus at 250 캜 is within the above range, the heat resistance is more excellent.

The storage elastic modulus was measured using a film visor of a device named "ARES" (manufactured by Rheometrics Co., Ltd.) using a film jig at a heating rate of 5 ° C / min, a frequency of 1 Hz and a distortion of 0.1% It can be measured by conditions.

&Lt; Adhesive sheet &

The adhesive sheet according to the present invention is a sheet having an adhesive layer formed by the above adhesive composition. The constitution of the adhesive sheet is not particularly limited as long as it has the above-mentioned adhesive layer. For example, the substrate may be a substrate-mounting adhesive sheet having a base material or an inorganic material adhesive sheet having no base material.

In the case where the adhesive sheet is a substrate-mounting adhesive sheet, it is sufficient that an adhesive layer of the adhesive composition is formed on at least one surface of the substrate, and an adhesive layer other than the adhesive layer, for example, a known adhesive Layer or an adhesive layer may be formed. Alternatively, an adhesive layer made of the above adhesive composition may be formed on both sides of the substrate.

The adhesive sheet may be formed in the form of a sheet, a tape, or the like. For example, it may be formed in a roll-wound form, or a plurality of sheets of adhesive sheets may be laminated.

Further, the adhesive sheet disclosed herein may have another layer (for example, an intermediate layer, a subbing layer or the like) within a range not to impair the effect of the present invention.

The above-mentioned adhesive sheet can be produced by a conventional method of producing an adhesive tape or sheet. For example, when the adhesive sheet is an inorganic adhesive sheet, the adhesive composition solution may be coated on the release surface of the release liner so that the thickness after drying becomes a predetermined thickness and dried.

(For example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray roll coater, etc.) can be used for application of the adhesive composition solution.

In the preferred embodiment of the adhesive sheet, the curing reaction does not substantially proceed at room temperature. Such an adhesive sheet is preferable because it can be stored at room temperature for a long period of time and can be cured by heating and can be firmly adhered to an adherend.

In a preferred embodiment of the above-mentioned adhesive sheet, the adhesive sheet exhibits adhesiveness at room temperature and can be easily adhered to an adherend. Such an adhesive sheet is preferable from the standpoints of temporary fixability and positioning. Specifically, as the adhesive force at the time of adhesion, the adhesive sheet was pressed and bonded to the polyimide at a rate of 100 kg / min after peeling the adhesive sheet for 15 minutes, Is preferably 0.5 to 8 N / 20 mm.

The flexible printed circuit board (FPC) often undergoes a high-temperature reflow process until it is embedded in the final product. For this reason, it is required that the adhesive sheet used for the FPC does not cause lifting or expansion after the reflow process. In addition, from the viewpoint of reliability, it is required that there is no lifting or expansion (good heat resistance after wet heat) even in a heat resistance test after wet heat treatment under more stringent conditions. The adhesive sheet according to the present invention can exhibit a balanced performance as a thermosetting adhesive, and further exhibits excellent heat resistance (especially heat resistance after wet heat) after thermal curing.

The adhesive sheet can be stored at room temperature for a long period of time, and can be adhered with good adhesive properties while having excellent heat resistance. Therefore, the adhesive sheet of the present invention can be suitably used for applications which require long-term shelf-life at room temperature, are robust by heating, and are required to be adhered with excellent heat resistance. Specifically, the adhesive sheet can be suitably used at the time of bonding in a flexible printed circuit board (FPC).

Adhesion of the FPC means adhesion at the time of manufacturing the FPC or adhesion at the time of bonding the FPC to the reinforcing plate as described above. The adhesive layer may be formed on the FPC by bonding the adhesive sheet to the FPC at the time of adhering. Accordingly, what is disclosed in this specification includes an FPC having an adhesive layer formed by any one of the adhesive compositions disclosed herein.

(Adhesive layer)

The adhesive layer is formed by the adhesive composition as described above. It is preferable that the adhesive layer is a thermosetting adhesive layer having a stable storage property at room temperature, a hardening reaction caused by heating, an increase in adhesive strength, and an adhesive property capable of bonding with excellent heat resistance.

The thickness of the adhesive layer is preferably 5 to 100 占 퐉, more preferably 10 to 50 占 퐉, and still more preferably 20 to 40 占 퐉, from the viewpoints of adhesiveness and workability. The adhesive layer may have a single layer, that is, a single layer, or a multi-layer, that is, a layer including two or more layers. The multi-layered adhesive layer may constitute a laminate.

The adhesive layer may be protected by a release liner. The release liner is not particularly limited and may be appropriately selected from known release liner.

(materials)

When the adhesive sheet has a base material, the base material is not particularly limited, and for example, a paper base material such as paper; Fiber-based materials such as cloth, nonwoven fabric, and net; Metal base materials such as metal foil and metal plate; (PPS), polyphenylene sulfide (PPS), and the like, for example, an olefin resin, a polyester resin, a polyvinyl chloride resin, a vinyl acetate resin, an amide resin, a polyimide resin, Plastic-based substrates such as films and sheets; Rubber base materials such as rubber sheets; A foam such as a foam sheet; A laminate of these layers; May be used. Examples of the laminate include a laminate of a plastic base material and another base material, and a laminate of plastic films (or sheets).

The thickness of the substrate is not particularly limited and is preferably 10 to 500 mu m, more preferably 12 to 200 mu m, and still more preferably 15 to 100 mu m. Further, the base material may have a single layer form or a multi-layer form. In addition, the substrate may be subjected to various treatments such as back surface treatment, antistatic treatment, priming treatment and the like, if necessary.

[Example]

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to the following examples and comparative examples at all. In the following description, &quot; part &quot; and &quot;% &quot; are based on weight unless otherwise specified.

&Lt; Example 1 >

Azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane} dihydrochloride was added to a reactor equipped with a stirrer, a thermometer, (Trade name: VA-060, manufactured by Wako Pure Chemical Industries, Ltd.) (initiator) and 100 g of ion-exchanged water were charged and stirred for 1 hour while introducing nitrogen gas. 72 parts by weight of butyl acrylate, 27 parts by weight of acrylonitrile, 1 part by weight of acrylic acid, 0.04 part by weight of dodecane thiol (chain transfer agent) and sodium polyoxyethylene lauryl ether sulfate (emulsifying agent) (Emulsion of monomer raw material) was gradually added dropwise over 3 hours to proceed an emulsion polymerization reaction. After completion of dropwise addition of the monomer raw material emulsion, the mixture was kept at the same temperature for 3 hours and aged. The aqueous dispersion (emulsion) of the acrylic polymer thus polymerized was dried to obtain an acrylic polymer.

A methanol solution in which 7.5 parts by weight of a phenol resin was dissolved and an ethyl acetate solution in which 7.5 parts by weight of an epoxy resin and 5 parts by weight of a black pigment were dissolved were mixed and stirred in an ethyl acetate solution containing 100 parts by weight of the acrylic polymer dissolved therein to obtain a thermosetting adhesive composition Solution. As the phenol resin, a trade name "SUMILITE RESIN PR-51283" (Sumitomo Bakelite Co., Ltd., a coal acid type resol-type phenol resin having a liquid state at 50 ° C) was used. As the epoxy resin, a trade name "JER1001" (bisphenol A type epoxy resin having an epoxy equivalent of 450 to 500 at a softening point of 64 ° C, manufactured by Japan Epoxy Resins Co., Ltd.) was used. As the black pigment, trade name &quot; AT DN102 Black &quot;, manufactured by Dainichi Seiko Co., Ltd., was used.

The thermosetting adhesive composition solution was coated on the release layer surface of the release liner so that the thickness after drying was 35 占 퐉 and dried at 100 占 폚 for 3 minutes to obtain a thermosetting adhesive sheet.

&Lt; Examples 2 to 14 and Comparative Examples 1 to 5 >

Each of the thermosetting adhesive sheets was produced in the same manner as in Example 1 except that the components and the amounts of the additives shown in Table 1 were changed.

<Evaluation method>

The following evaluations were performed on the adhesive sheets obtained in the respective Examples and Comparative Examples.

(1) visibility

Layer structure of polyimide film 25 占 퐉 / adhesive layer 25 占 퐉 / Cu wiring layer 35 占 퐉 / adhesive layer 15 占 퐉 / polyimide film 25 占 퐉 / adhesive layer 15 占 퐉 / Cu wiring layer 35 占 퐉 / adhesive layer 25 占 퐉 / polyimide film 25 占 퐉 (Size: 5 cm x 8 cm, thickness: 0.2 mm, width of Cu wiring layer: 150 mu m, gap between Cu wiring: 100 mu m) made of a flexible printed circuit board Lt; RTI ID = 0.0 &gt; 130 C. &lt; / RTI &gt; The case where the FPC was turned over and the presence or absence of tape bonding was clearly confirmed at a distance of 1 m from the other side of the FPC via the transmitting portion (gap between the Cu wiring layers) was evaluated as &amp; cir &amp; The case was evaluated as x.

(2) Adhesion

The adhesive force (N / cm) at 23 占 폚 of the cured adhesive layer in the adhesive sheets obtained in the examples and comparative examples was evaluated by the following method.

The flexible printed circuit board (FPC; size: 5 cm x 8 cm, thickness: 0.2 mm) and the adhesive sheet were laminated at 130 DEG C and then cut into 1 cm width Polyimide). &Lt; / RTI &gt; This was attached to a SUS304BA plate (size: 5 cm x 5 cm), laminated at 130 DEG C, and then heat-pressed at 160 DEG C and 1 MPa for 90 seconds. The sample was cured at 150 占 폚 for 3 hours to prepare a test sample.

(Tensile speed: 50 mm / min, 23 ° C) (N / mm 2) was obtained by pulling the FPC side by using the apparatus "TCM-1kNB" (manufactured by Minebea Co., Ltd.) Cm) was measured.

After the cure, the test piece was subjected to a reflow process under the conditions described in paragraph 0081 of Japanese Patent Application Laid-Open No. 2010-65078, and then subjected to a 90 ° peel adhesion force (tensile rate: 50 mm / Min, 23 占 폚) (N / cm) were measured.

Further, after the reflow process, the test piece was immersed in ion-exchanged water at 50 ° C for 1 hour, and then the test piece was lifted from the ion-exchange water, and the water droplet on the surface of the test piece was wiped off with an oil mop. (Tensile rate: 50 mm / min, 23 deg. C) (N / cm) was measured by the same method as that described above.

(3) Heat resistance

The adhesive sheet and the adhesive sheet were laminated at 130 占 폚 and then cut into a width of 1 cm (the adhesive sheet was made of CCL (polyvinylidene fluoride) Laminated to the entire surface of the polyimide surface). This was attached to a polyimide plate (PI (size: 5 cm x 5 cm, thickness: 0.13 mm), laminated at 130 deg. C, and then heated and pressed at 160 deg. The sample was cured at 150 DEG C for 3 hours to prepare a test sample.

The test piece was allowed to stand under the conditions of humidification (temperature: 60 占 폚, humidity: 90% RH) for 24 hours and then subjected to a reflow process under the conditions of peak temperature: The conditions described in paragraph 0081 of Japanese Patent Application Laid-Open No. 2010-65078), and in each step, the state of foaming and peeling of the adhesive layer in the adhesive sheet was visually observed.

Quot ;, &quot;? &Quot;, and &quot;? &Quot;, respectively, indicating that the adhesive layer was not peeled off or peeled off, &quot; .

(4) Gel fraction

The adhesive sheets obtained in Examples and Comparative Examples were each peeled off from the release liner in a size of 5 cm x 5 cm and a porous tetrafluoroethylene sheet (trade name: "NTF1122", manufactured by Nitto Denko Corporation Ltd.), bundled with a burning chamber, and the weight at that time is measured, and the weight is defined as the weight before immersion. Also, the weight before immersion is the total weight of the adhesive layer, the tetrafluoroethylene sheet, and the smoke chamber. Further, the total weight of the tetrafluoroethylene sheet and the combustion chamber is also measured, and the weight of the tetrafluoroethylene sheet is taken as the weight of the bag.

As the adhesive sheet, an adhesive sheet before curing and an adhesive sheet after curing were used.

Subsequently, the adhesive sheet was placed in a 50 ml container filled with methyl ethyl ketone and surrounded by a tetrafluoroethylene sheet (hereinafter referred to as a &quot; sample &quot;). ). Thereafter, a sample (after treatment with methyl ethyl ketone) was taken out from the vessel, transferred to an aluminum cup, and dried at 130 캜 for 2 hours in a drier to remove methyl ethyl ketone. Then, the weight was measured, Weight.

Then, the gel fraction is calculated from the following equation.

Gel fraction (% by weight) = (A-B) / (C-B) x 100 (1)

(In the formula (1), A is the weight after immersion, B is the weight of the bag, and C is the weight before immersion)

The abbreviations in the tables have the following meanings.

Colorant 1: Black pigment (trade name &quot; AT DN102 Black &quot;, manufactured by Dainichiseika Chemical Co., Ltd.)

Colorant 2: White pigment (trade name &quot; NPE-1006 &quot;, manufactured by Dainichiseika Chemical &amp;

Colorant 3: White pigment (trade name &quot; R-2228 &quot;, manufactured by Dainichiseika Chemical &amp;

Colorant 4: Blue dye (trade name &quot; ORIPACS GN-28 &quot;, manufactured by Orient Kagaku Co., Ltd.)

Colorant 5: Green dye (trade name: OPLAS GREEN 533, manufactured by Orient Kagaku Kogyo Co., Ltd.)

Colorant 6: Green dye (trade name &quot; OIL GREEN 502 &quot;, manufactured by Orient Kagaku Kogyo Co., Ltd.)

The present invention is not limited to the above-described embodiments, but may be modified in various ways within the scope of the claims, and is also encompassed in the technical scope of the present invention in embodiments obtained by suitably combining the technical means disclosed in the other embodiments .

Claims (10)

An acrylic resin composition comprising an acrylic polymer, a phenol resin, an epoxy resin, and a colorant,
Wherein the coloring agent is contained in an amount of 10 parts by weight or less based on 100 parts by weight of the acrylic polymer. The adhesive composition according to claim 1, wherein the phenolic resin is contained in an amount of 5 to 20 parts by weight based on 100 parts by weight of the acrylic polymer. The adhesive composition according to claim 1 or 2, wherein the phenol resin comprises a resol-type phenol resin, and the resol-type phenol resin is contained in an amount of 5 to 20 parts by weight based on 100 parts by weight of the acrylic polymer. 4. The adhesive composition according to any one of claims 1 to 3, wherein the epoxy resin is contained in an amount of 5 to 20 parts by weight based on 100 parts by weight of the acrylic polymer. The adhesive composition according to any one of claims 1 to 4, wherein the colorant is a dye or a pigment. 6. The adhesive composition according to any one of claims 1 to 5, wherein the coloring agent is a black, blue or green pigment or dye. The acrylic polymer according to any one of claims 1 to 6, wherein the acrylic polymer comprises 50 to 85% by weight of a (meth) acrylic acid C _{2 -14} alkyl ester (a), 10 to 45 By weight, and a monomer component containing a carboxyl group-containing monomer (c) in a proportion of 0.1 to 7% by weight. An adhesive sheet formed by the adhesive composition according to any one of claims 1 to 7. 9. The adhesive composition according to claim 8, comprising an adhesive layer formed by the adhesive composition according to any one of claims 1 to 7,
Wherein the adhesive layer is a thermosetting adhesive layer. A flexible circuit board having an adhesive layer formed by the adhesive composition according to any one of claims 1 to 7.