TW201326349A - Thermosetting adhesive sheet and laminate - Google Patents

Abstract

The purpose of the present invention is to provide a thermosetting adhesive sheet which exhibits excellent adhesiveness and excellent heat resistance after exposure to humidity and heat even in cases where the curing time is short, while having excellent thermal conductivity. A thermosetting adhesive sheet of the present invention has a thermosetting adhesive layer that is formed from a thermosetting adhesive composition, and is characterized in that: the thermosetting adhesive composition contains an acrylic polymer (X) as a main component; the thermosetting adhesive composition also contains an etherified phenolic resin (Y); and the thermosetting adhesive layer has a thickness of 1-20 mum.

Description

Thermoset type sheet and laminate

This invention relates to a thermoset backsheet having a thermoset adhesive layer. More specifically, the present invention relates to a thermosetting back sheet which can be preferably used in a flexible printed circuit board or the like. Further, the present invention relates to a laminate having the thermosetting adhesive sheet and a flexible printed circuit board.

A flexible printed circuit board (there is a case called "FPC") is widely used in electronic equipment. In the 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 in the process of adhering the FPC to a reinforcing plate such as an aluminum plate, a stainless steel plate, or a polyimide plate.

As a binder used in the case of such an FPC, a thermosetting adhesive containing a thermosetting resin such as a phenol resin or an epoxy resin is known. These thermosetting adhesives, for example, the thermosetting resin contained in the adhesive are cured by heating at 150 ° C or higher, thereby exerting an adhesive force.

When the layered body produced by using the above-mentioned thermosetting type adhesive and then the body (FPC or the like) is treated in a high temperature step such as a reflow step, there are the following cases: moisture contained in the adhesive or the adherend Evaporation, thereby causing foaming (bulging) or floating peeling of the adhesive. In many cases, these phenomena are caused by insufficient curing of the adhesive, and in order to sufficiently cure them, there is a problem that it is necessary to increase the curing temperature and increase the curing time. Therefore, to solve In the above-mentioned problem, as a thermosetting adhesive sheet having a thermosetting adhesive layer excellent in curability, a thermosetting adhesive sheet having the following thermosetting adhesive layer, which is a thermosetting adhesive layer, is known. It is formed of a thermosetting adhesive composition containing an acrylic polymer as a main component and further containing an etherified phenol resin (see Patent Document 1).

Prior technical literature Patent literature

Patent Document 1: International Publication No. 2011/004710

However, in recent years, from the viewpoint of productivity improvement, it is required to further shorten the curing time. Therefore, it is required to exhibit excellent adhesion and heat resistance after damp heat even when the curing time is shortened (even when it is treated in a high temperature step after storage under high temperature and high humidity conditions, it is difficult to produce an adhesive agent). The subsequent sheet of the layer is characterized by foaming or lifting and peeling.

In addition, in recent years, with the miniaturization and thinning of an electronic device using FPC, the degree of integration of electronic components in an electronic device tends to increase, and FPC has a large amount of heat. In order to dissipate the heat accumulated in the FPC, thermal conductivity is required for the adhesive (following the sheet) used in the subsequent FPC.

Therefore, an object of the present invention is to provide a thermosetting back sheet which exhibits excellent adhesion and heat resistance after moist heat even when the curing time is short, and which is excellent in heat dissipation property, that is, thermal conductivity.

Therefore, in order to solve the above problems, the inventors conducted intensive studies and found that by providing a special shape formed by a specific thermosetting adhesive composition A thermosetting adhesive layer having a constant thickness can obtain a thermosetting adhesive sheet which exhibits excellent adhesion, heat resistance after moist heat, and excellent thermal conductivity even when the curing time is short. this invention.

That is, the present invention provides a thermosetting adhesive sheet comprising a thermosetting adhesive layer formed of a thermosetting adhesive composition, and the above thermosetting adhesive composition contains an acrylic polymer (X) as a main component, and contains an etherified phenol resin (Y), and the thickness of the above-mentioned thermosetting type adhesive layer is 1 to 20 μm.

The thermosetting adhesive sheet of the present invention is preferably cured at 150 ° C for 60 minutes, and the total heat resistance of the above-mentioned thermosetting adhesive layer is 2.0 (cm ^{2 ·} K) / W or less.

The acrylic polymer (X) is preferably an acrylic polymer composed of an alkyl (meth)acrylate (a) having a linear or branched alkyl group having 1 to 14 carbon atoms as an essential monomer component. Things.

The acrylic polymer (X) is preferably an acrylic polymer comprising a cyano group-containing monomer (b) and a carboxyl group-containing monomer (c) as essential monomer components.

The content of the etherified phenol resin (Y) is preferably from 1 to 40 parts by weight based on 100 parts by weight of the acrylic polymer (X).

The thermoset adhesive sheet of the present invention preferably comprises only a thermosetting adhesive layer without a substrate.

The thermosetting back sheet of the present invention is preferably a thermosetting back sheet for a flexible printed circuit board.

Moreover, the present invention provides a laminated body that is attached to a flexible printed circuit base. The board has the above-mentioned thermosetting type of sheet.

Further, the present invention provides a thermosetting thermosetting back sheet which is obtained by subjecting the above-mentioned thermosetting sheet to thermosetting.

Further, the present invention provides a laminate comprising the above-described thermoset thermosetting back sheet on a flexible printed circuit board.

The thermosetting back sheet of the present invention has the above-described constitutional characteristics, and thus exhibits excellent adhesion, heat resistance after moist heat, and excellent thermal conductivity even when the curing time is short. In particular, the thermosetting thermosetting sheet obtained by thermosetting the thermosetting sheet of the present invention can exhibit excellent adhesion and heat resistance after damp heat even when the curing time is short. And excellent in thermal conductivity.

Hereinafter, embodiments of the present invention will be described in detail.

The thermosetting adhesive sheet of the present invention has at least a thermosetting adhesive layer which is composed of an acrylic polymer (X) as a main component and a thermosetting resin containing an etherified phenol resin (Y). A type of adhesive composition is formed. In the present specification, the above-mentioned "thermosetting adhesive composition containing an acrylic polymer (X) as a main component and containing an etherified phenol resin (Y)" is referred to as "the thermosetting type of the present invention". The case of the subsequent composition. Further, the above-mentioned "thermosetting type adhesive layer formed of a thermosetting adhesive composition containing an emulsified phenol resin (Y) containing an acrylic polymer (X) as a main component" (that is, the heat of the present invention) The thermosetting adhesive layer formed of the solid adhesive composition is referred to as "the thermosetting adhesive layer of the present invention".

In the present specification, the phrase "containing the acrylic polymer (X) as a main component" means the acrylic polymer (X) in all the nonvolatile components (100% by weight) of the thermosetting adhesive composition of the present invention. The content is 50% by weight or more.

In addition, "thermoset type follower" is also included in "thermoset type sheet". That is, the thermosetting adhesive sheet of the present invention may be a thermosetting adhesive tape having a belt-like form.

[The thermosetting adhesive composition of the present invention]

The thermosetting adhesive composition of the present invention contains an acrylic polymer (X) and an etherified phenol resin (Y) as essential components. The thermosetting adhesive composition of the present invention may contain a solvent (solvent and/or dispersion medium) in addition to the acrylic polymer (X) and the etherified phenol resin (Y), and may contain an additive. Each of the above components (acrylic polymer (X), etherified phenol resin (Y), solvent or additive) may be used alone or in combination of two or more.

(acrylic polymer (X))

The acrylic polymer (X) is not particularly limited, and it is preferably an alkyl (meth)acrylate (a) having a linear or branched alkyl group having 1 to 14 carbon atoms as an essential monomer component. An acrylic polymer that is formed (or formed). In the present specification, the above-mentioned "alkyl (meth)acrylate (a) having a linear or branched alkyl group having 1 to 14 carbon atoms is referred to as "(meth)acrylic acid C _{1 ). -14} alkyl ester (a)" or simply "alkyl (meth)acrylate (a)". Further, the term "(meth)acrylic acid" means "acrylic acid" and/or "methacrylic acid" (one or both of "acrylic acid" and "methacrylic acid"), and the same applies hereinafter.

The acrylic polymer (X) is more preferably an essential monomer of a C _1-14 alkyl (meth)acrylate (a), a cyano group-containing monomer (b), and a carboxyl group-containing monomer (c). An acrylic polymer composed of components. In particular, it is preferred that the content of the C _1-14 alkyl (meth)acrylate (a) in the total amount of the monomer components (100% by weight) constituting the acrylic polymer (X) is 50 to 75% by weight. The content of the cyano group-containing monomer (b) is 20 to 49.5% by weight, and the content of the carboxyl group-containing monomer (c) is 0.5 to 10% by weight. Further, as the monomer component constituting the acrylic polymer (X), the above-mentioned (meth)acrylic acid C _1-14 alkyl ester (a), the cyano group-containing monomer (b), and the carboxyl group-containing one may be used. A monomer component (other monomer component) other than the monomer (c).

The acrylic polymer (X) is preferably an acrylic polymer (acrylic elastomer) which exhibits rubber elasticity (elastic property).

The C _1-14 alkyl (meth)acrylate (a) is not particularly limited, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate. , (isopropyl) (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, second butyl (meth)acrylate, tert-butyl (meth)acrylate, (A) Ethyl pentyl acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , isooctyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, (meth)acrylic acid A monoalkyl ester, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, and the like. Among them, an alkyl (meth)acrylate (C _4-12 alkyl (meth)acrylate) having a linear or branched alkyl group having 4 to 12 carbon atoms is preferred, and n-butyl acrylate is preferred. ester. The above C _1-14 alkyl (meth)acrylate (a) may be used singly or in combination of two or more.

The (meth)acrylic acid C _1-14 alkyl ester (a) constituting the monomer component of the acrylic polymer (X) with respect to the total amount of the monomer component (100% by weight) constituting the acrylic polymer (X) The content (content ratio) is 50% by weight or more, preferably 50 to 75% by weight, more preferably 55 to 75% by weight, still more preferably 60 to 72% by weight.

When the content is 50% by weight or more, the acrylic polymer (X) becomes a relatively hard polymer, and the strength (block strength) of the thermosetting adhesive layer of the present invention can be improved, and the heat resistance after moist heat can be improved.

The cyano group-containing monomer (b) is a monomer having a cyano group, and is not particularly limited, and examples thereof include acrylonitrile and methacrylonitrile. Among them, acrylonitrile is preferred. The above cyano group-containing monomer (b) may be used singly or in combination of two or more.

By using the cyano group-containing monomer (b), the strength (block strength) of the thermosetting adhesive layer of the present invention can be improved, and the heat resistance after moist heat is improved, which is preferable. Further, it is preferable to prevent the thermosetting adhesive layer of the present invention from becoming brittle.

The content of the cyano group-containing monomer (b) constituting the monomer component of the acrylic polymer (X) is preferably the content of the monomer component (100% by weight) constituting the acrylic polymer (X). 20 to 49.5% by weight, more preferably 24 to 40% by weight, still more preferably 26 to 35% by weight.

When the content is 20% by weight or more, the heat-resistant heat-sensitive sheet of the present invention is further improved in heat resistance after moist heat, which is preferable. On the other hand, if When the content exceeds 49.5% by weight, the flexibility of the thermosetting adhesive layer may be lowered.

The carboxyl group-containing monomer (c) is a monomer having a carboxyl group, and is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Wait. Further, an acid anhydride of the carboxyl group-containing monomer (for example, an acid anhydride group-containing monomer such as maleic anhydride or itaconic anhydride) is also included in the carboxyl group-containing monomer. Among them, acrylic acid, methacrylic acid, and itaconic acid are preferred, and acrylic acid is preferred. The above carboxyl group-containing monomer (c) may be used singly or in combination of two or more. It is preferred to use the carboxyl group-containing monomer (c) to improve the heat resistance and adhesion of the heat-curable pressure-sensitive adhesive sheet of the present invention after moist heat.

The content of the carboxyl group-containing monomer (c) in the monomer component constituting the acrylic polymer (X) is preferably 0.5 with respect to the total amount of the monomer component (100% by weight) constituting the acrylic polymer (X). It is preferably 10% by weight, more preferably 1% by weight to 8% by weight, still more preferably 2% by weight to 6% by weight.

When the content is 0.5% by weight or more, the heat-resistant heat-sensitive sheet of the present invention is preferred because it has improved heat resistance and adhesion after moist heat. On the other hand, when the content exceeds 10% by weight, the flexibility of the thermosetting adhesive layer may be lowered.

The monomer component constituting the acrylic polymer (X) includes the above-mentioned (meth)acrylic acid C _1-14 alkyl ester (a), the above cyano group-containing monomer (b), and the above carboxyl group-containing monomer. In addition to (c), other monomer components (copolymerizable monomers) may also be used. The above other monomer components (copolymerizable monomers) may be used singly or in combination of two or more. Examples of the other monomer component (copolymerizable monomer) include pentadecyl (meth)acrylate, cetyl (meth)acrylate, and heptadecyl (meth)acrylate. , octadecyl (meth) acrylate, hexadecyl (meth) acrylate, eicosyl (meth) acrylate, etc. having a linear or branched alkyl group having a carbon number of 15-20 Alkyl (meth)acrylate (C _15-20 alkyl (meth)acrylate); cycloalkyl (meth)acrylate [cyclohexyl (meth)acrylate, etc.] or (meth)acrylic acid (meth) acrylate containing a non-aromatic ring such as borneol ester; aryl (meth) acrylate [phenyl (meth) acrylate], aryloxyalkyl (meth) acrylate [(A) (meth)acrylic acid ester such as phenoxyethyl acrylate or the like, arylalkyl (meth) acrylate [benzyl methacrylate], etc.; (meth) acrylate; An epoxy group-containing acrylic monomer such as glycidyl ester or (meth)acrylic acid methyl glycidyl ester; a vinyl ester monomer such as vinyl acetate or vinyl propionate; styrene or α-methylstyrene; Styrene monomer; a hydroxyl group-containing monomer such as hydroxyethyl methacrylate, hydroxypropyl (meth)acrylate or hydroxybutyl (meth)acrylate; methoxyethyl (meth)acrylate or ethoxylated (meth)acrylate Alkoxyalkyl (meth) acrylate monomer such as ethyl ester; aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, (methyl) Aminoalkyl (meth) acrylate monomer such as tributylaminoethyl acrylate; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (N-substituted) guanamine monomer such as (meth) acrylamide or N-hydroxy (meth) acrylamide; olefin monomer such as ethylene, propylene, isobutylene or butadiene; methyl vinyl ether A vinyl ether monomer or the like.

Further, as the other monomer component (copolymerizable monomer), hexanediol di(meth)acrylate, butanediol di(meth)acrylate, or (poly) may be used. Ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, glycerol di(methyl) A polyfunctional monomer such as acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, or divinylbenzene.

In other words, the acrylic polymer (X) preferably contains at least a structural unit derived from a C _1-14 alkyl (meth)acrylate (a), a structural unit derived from a cyano group-containing monomer (b), And an acrylic polymer derived from a structural unit of the carboxyl group-containing monomer (c). Each of the structural units may be one type or two or more types. The content of the structural unit derived from the C _1-14 alkyl (meth)acrylate (a) in the acrylic polymer (X) (100% by weight) is preferably 50% by weight or more, more preferably 50 to 75. The weight % is further preferably 55 to 75% by weight, most preferably 60 to 72% by weight. The content of the structural unit derived from the cyano group-containing monomer (b) is preferably from 20 to 49.5% by weight, more preferably from 24 to 40% by weight, still more preferably from 26 to 35% by weight. The content of the structural unit derived from the carboxyl group-containing monomer (c) is preferably from 0.5 to 10% by weight, more preferably from 1 to 8% by weight, still more preferably from 2 to 6% by weight.

The above acrylic polymer (X) may be used singly or in combination of two or more. In order to make the acrylic polymer (X) have both adhesiveness and heat resistance, at least two kinds of acrylic polymers (X) may be used in combination, and at least the acrylic polymer (X1) and the acrylic polymer may be used ( X2) used in combination.

Examples of the acrylic polymer (X1) include an alkyl (meth)acrylate (a1) having a linear or branched alkyl group having 1 to 3 carbon atoms (the presence of "(methyl) is present). In the case of a C _1-3 alkyl acrylate (a1)", an acrylic polymer which is formed (or formed) as an essential monomer component, or a C _1-3 alkyl (meth)acrylate (a1), The cyano group-containing monomer (b1) and the carboxyl group-containing monomer (c1) are acrylic monomers composed of essential monomer components. Each of the structural units may be one type or two or more types. Further, as the monomer component constituting the acrylic polymer (X1), the above-mentioned (meth)acrylic acid C _1-3 alkyl ester (a1), the cyano group-containing monomer (b1), and the carboxyl group-containing one may be used. A monomer component (other monomer component) other than the monomer (c1).

The above-mentioned C _1-3 alkyl (meth)acrylate (a1) can be, for example, a linear or branched carbon having a carbon number of 1 to 3 in the above C _1-14 alkyl (meth)acrylate (a). Alkyl alkyl (meth)acrylate. As the cyano group-containing monomer (b1), for example, a cyano group-containing monomer selected from the above cyano group-containing monomer (b) can be used. As the carboxyl group-containing monomer (c1), a carboxyl group-containing monomer selected from the above carboxyl group-containing monomer (c) can be used.

In the total amount (100% by weight) of the monomer components constituting the acrylic polymer (X1), the content of the C _1-3 alkyl (meth)acrylate (a1) is preferably 50% by weight or more, more preferably 50 to 75% by weight, more preferably 55 to 75% by weight, most preferably 60 to 72% by weight. The content of the cyano group-containing monomer (b1) is preferably from 20 to 49.5% by weight, more preferably from 24 to 40% by weight, still more preferably from 26 to 35% by weight. The content of the carboxyl group-containing monomer (c1) is preferably from 0.5 to 10% by weight, more preferably from 1 to 8% by weight, still more preferably from 2 to 6% by weight.

The acrylic polymer (X2) may, for example, be an alkyl (meth)acrylate (a2) having a linear or branched alkyl group having 4 to 14 carbon atoms (the presence of "(methyl) ) In the case of a C _4-14 alkyl acrylate (a2)", an acrylic polymer which is formed (or formed) as an essential monomer component, or a C _4-14 alkyl (meth)acrylate (a2) The cyano group-containing monomer (b2) and the carboxyl group-containing monomer (c2) are an acrylic polymer composed of an essential monomer component. Each of the structural units may be one type or two or more types. Further, as the monomer component constituting the acrylic polymer (X2), the above-mentioned (meth)acrylic acid C _4-14 alkyl ester (a2), cyano group-containing monomer (b2), and carboxyl group-containing may be used. A monomer component (other monomer component) other than the monomer (c2).

The above C _4-14 alkyl (meth)acrylate (a2) may, for example, be a linear or branched carbon having a carbon number of 4 to 14 in the above C _1-14 alkyl (meth)acrylate (a). Alkyl alkyl (meth)acrylate. As the cyano group-containing monomer (b2), for example, a cyano group-containing monomer selected from the above cyano group-containing monomer (b) can be used. As the carboxyl group-containing monomer (c2), a carboxyl group-containing monomer selected from the above carboxyl group-containing monomer (c) can be used.

In the total amount (100% by weight) of the monomer components constituting the acrylic polymer (X2), the content of the C _4-14 alkyl (meth)acrylate (a2) is preferably 50% by weight or more, more preferably 50 to 75% by weight, more preferably 55 to 75% by weight, most preferably 60 to 72% by weight. The content of the cyano group-containing monomer (b2) is preferably from 20 to 49.5% by weight, more preferably from 24 to 40% by weight, still more preferably from 26 to 35% by weight. The content of the carboxyl group-containing monomer (c2) is preferably from 0.5 to 10% by weight, more preferably from 1 to 8% by weight, still more preferably from 2 to 6% by weight.

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

Further, the polymerization initiator, the emulsifier, the chain transfer agent, and the like which are used as needed in the polymerization of the acrylic polymer (X) are not particularly limited, and are known from the above. Or choose appropriate use among the idiots. More specifically, examples of the polymerization initiator include 2,2'-azobisisobutyronitrile and 2,2'-azobis(4-methoxy-2,4-dimethyl Valeronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis ( Cyclohexane-1-carbonitrile), 2,2'-azobis(2,4,4-trimethylpentane), dimethyl-2,2'-azobis(2-methylpropane) An azo polymerization initiator such as an acid ester) or 2,2'-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane} dihydrochloride; Benzoyl peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, dicumyl peroxide, 1,1-double (peroxidized third A peroxide-based polymerization initiator such as -3,3,5-trimethylcyclohexane or 1,1-bis(t-butylperoxy)cyclododecane. The above polymerization initiators may be used singly or in combination of two or more. The amount of the polymerization initiator to be used is not particularly limited, and can be appropriately selected from the range of the usual usage amount.

Examples of the chain transfer agent include 1-dodecyl mercaptan, third lauryl mercaptan, second lauryl mercaptan, 2-mercaptoethanol, glycidyl mercaptan, mercaptoacetic acid, and thioglycolic acid 2-B. Hexyl hexyl ester, 2,3-dimercapto-1-propanol, α-methylstyrene dimer, and the like. Examples of the emulsifier include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, ammonium polyoxyethylene alkylphenyl ether sulfate, and polyoxyethylene. An anionic emulsifier such as an alkylphenyl ether sulfate; a nonionic emulsifier such as a polyoxyethylene alkyl ether or a polyoxyethylene alkylphenyl ether. The above chain transfer agent and the above emulsifier may be used alone or in combination of two or more.

Further, in the solution polymerization, various usual solvents can be used. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; An aromatic hydrocarbon such as benzene or benzene; an aliphatic hydrocarbon such as n-hexane or n-heptane; an alicyclic hydrocarbon such as cyclohexane or methylcyclohexane; or a ketone such as methyl ethyl ketone or methyl isobutyl ketone. Organic solvents such as a class. The above solvents may be used singly or in combination of two or more.

The weight average molecular weight (Mw) of the acrylic polymer (X) is not particularly limited, and the viewpoint of improving the coatability of the thermosetting adhesive composition of the present invention to improve productivity is enhanced or the thermosetting of the present invention is enhanced. The viewpoint of the strength of the adhesive layer and the heat resistance after moist heat is preferably from 500,000 to 4,000,000, more preferably from 600,000 to 3.5 million, and still more preferably from 800,000 to 3.2 million.

The weight average molecular weight of the acrylic polymer (X) can be controlled by the kind of the polymerization initiator or the chain transfer agent or the amount thereof to be used, the temperature or time during polymerization, the monomer concentration, the monomer droplet acceleration, and the like.

The above weight average molecular weight can be measured by gel permeation chromatography (GPC, Gel Permeation Chromatography). More specifically, for example, it can be measured and determined by the following <GPC measurement method>.

<Measurement method of GPC>

(Preparation of measurement sample)

The acrylic polymer to be measured was dissolved in a solution to prepare a 0.1% THF (Tetrahydrofuran) solution of the acrylic polymer, and the solution was allowed to stand for 1 day, and then filtered through a 0.45 μm membrane filter to obtain the obtained polymer. The filtrate was used as a measurement sample, and GPC measurement was performed under the following measurement conditions.

(measurement conditions)

GPC device: HLC-8320GPC (manufactured by Tosoh Corporation)

Pipe column: TSKgel GMH-H(S) (manufactured by Tosoh Corporation)

Column size: 7.8 mm I.D.×300 mm

Column temperature: 40 ° C

Lysate: THF

Flow rate: 0.5 mL/min

Inlet pressure: 4.6 MPa

Injection volume: 100 μl

Detector: differential refractometer

Standard sample: polystyrene

Data processing device: GPC-8020 (manufactured by Tosoh Corporation)

In the thermosetting adhesive composition of the present invention, the content (content ratio, blending ratio) of the acrylic polymer (X) is not particularly limited, and the heat resistance and the adhesive force after moist heat are relatively The non-volatile component (100% by weight) of the thermosetting adhesive composition of the present invention is 50% by weight or more, preferably 70 to 99% by weight, more preferably 80 to 95% by weight, still more preferably 85 to 8% by weight. 95% by weight.

When the acrylic polymer (X) contains, for example, an acrylic polymer (X1) and an acrylic polymer (X2), all nonvolatile components (100% by weight) of the thermosetting adhesive composition of the present invention The total amount (total content) of the content of the acrylic polymer (X1) and the content of the acrylic polymer (X2) is 50% by weight or more, preferably 70 to 99% by weight, more preferably 80 to 95% by weight. %, further preferably from 85 to 95% by weight.

In addition, the content (content ratio, blending ratio) of the acrylic polymer (X2) with respect to the acrylic polymer (X1) is not particularly limited, and both In terms of properties and heat resistance, it is preferably 1 to 100 parts by weight, more preferably 2 to 45 parts by weight, still more preferably 4 to 25 parts by weight, per 100 parts by weight of the acrylic polymer (X1). The optimum is 5 to 20 parts by weight. By setting the content of the acrylic polymer (X2) to 1 part by weight or more, the adhesion of the thermosetting sheet of the present invention is improved, and the heat resistance after moist heat is also improved, which is preferable. Moreover, by setting it to 100 parts by weight or less, the strength of the thermosetting adhesive layer of the present invention is improved, and the heat-resistant adhesive sheet of the present invention is improved in heat resistance after moist heat, which is preferable.

(etherified phenol resin (Y))

The etherified phenol resin (Y) is a phenol resin in which a part of the hydroxymethyl group (hydroxymethyl group in the phenol resin) is etherified. That is, a phenol resin having at least an etherified methylol group and an etherified methylol group. The etherified phenol resin (Y) is used to impart thermosetting properties. When the etherified phenol resin (Y) is excellent in reactivity at the time of heat curing, when the etherified phenol resin (Y) is used, the adhesion of the thermosetting adhesive layer of the present invention and the heat resistance after moist heat can be improved. The heat-set type of the invention is followed by thinning of the sheet.

Further, the etherified phenol resin (Y) is preferably an alkyl etherified phenol resin which is a phenol resin obtained by alkylating one of the methylol groups of the phenol resin. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a second butyl group, a tert-butyl group, a pentyl group, an isopentyl group, a hexyl group, and a glycol group. Base, octyl, 2-ethylhexyl, isooctyl, decyl, isodecyl, decyl, isodecyl, undecyl, dodecyl, tridecyl, tetradecyl, ten Pentaalkyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl and the like having an alkyl group of 1 to 20 carbon atoms. Among them, preferably A Base, ethyl, n-butyl, and further preferably n-butyl.

In the etherified phenol resin (Y), the phenol resin to be a skeleton is not particularly limited. Examples of the etherified phenol resin (Y) include an etherified novolak type phenol resin, an etherified resol type phenol resin, and an etherified cresol resin. Among them, an etherified cresol resin is preferred, and a butyl etherified cresol resin (a cresol resin in which one part of the methylol group is butyl etherified) is more preferred. The above etherified phenol resin (Y) may be used singly or in combination of two or more.

The ratio of the etherified methylol group in the above etherified phenol resin (Y), for example, relative to the total of the etherified methylol group and the unetherified methylol group (100 mol%), The proportion of the etherified methylol group is preferably 50 mol% or more (50 mol% or more and less than 100 mol%), more preferably 70 mol% or more. When the ratio of the etherified methylol group is less than 50 mol%, the reaction at the normal temperature of the etherified phenol resin may be promoted or the reactivity at the time of heat curing may be lowered.

As the etherified phenol resin (Y), a commercially available etherified phenol resin can be used, and for example, a product name "Sumilite Resin PR-55317" (manufactured by Sumitomo Bakelite Co., Ltd., butyl etherified cresol resin) can be used. The ratio of the etherified methylol group: 90 mol%), the trade name "CKS-3898" (manufactured by Showa Denko Co., Ltd., butyl etherified cresol resin), and the like.

In the thermosetting adhesive composition of the present invention, the content (content ratio, blending ratio) of the etherified phenol resin (Y) is preferably from 1 to 40 parts by weight based on 100 parts by weight of the acrylic polymer (X). More preferably, it is 5-20 parts by weight, and further preferably 10-15 parts by weight. By setting the content of the above etherified phenol resin (Y) It is preferred that the thermosetting adhesive layer of the present invention has a thermosetting property of 1 part by weight or more. Further, by setting it to 40 parts by weight or less, it is preferred that the adhesive does not bleed out when pressurized at a high temperature.

(solvent, additive)

The thermosetting adhesive composition of the present invention preferably contains a solvent. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; alcohols such as methanol, ethanol, butanol, propanol, and isopropanol; aromatic hydrocarbons such as toluene and benzene; and n-hexane. An aliphatic hydrocarbon such as heptane; an alicyclic hydrocarbon such as cyclohexane or methylcyclohexane; or an organic solvent such as a ketone such as methyl ethyl ketone or methyl isobutyl ketone. The above solvents may be used singly or in combination of two or more. Further, the meaning of the dispersion medium is also included in the above solvent.

In addition to the acrylic polymer (X) and the etherified phenol resin (Y), the thermosetting adhesive composition of the present invention may contain an anti-aging agent and a filler as needed within the scope of the characteristics of the present invention. A known additive such as a filler (filler), a colorant (pigment or dye, etc.), an ultraviolet absorber, an antioxidant, a crosslinking agent, an adhesion-imparting agent, a plasticizer, a softener, a surfactant, an antistatic agent, and the like. The above additives may be used singly or in combination of two or more.

The filler (filler) is not particularly limited, and a conventionally known organic filler or inorganic filler can be used. Among them, from the viewpoint of enhancing the strength of the thermosetting adhesive layer of the present invention and further improving the heat resistance after heat and humidity of the thermosetting adhesive sheet of the present invention, a cerium oxide filler or a copper filler is preferred. The above fillers may be used singly or in combination of two or more.

The shape of the above-mentioned ceria filler or the above-mentioned copper filler is not particularly limited, and examples thereof include a spherical shape, a filament shape, a scaly shape, a dendritic shape, and irregularity. Then shape and so on. Among them, in view of uniformly dispersing in the thermosetting adhesive layer of the present invention, the shape of the above-mentioned ceria filler or the above-mentioned copper filler is preferably spherical.

The average particle diameter of the above-mentioned ceria filler or the above-mentioned copper filler is not particularly limited, but is preferably 0.005 to 10 μm, more preferably 0.05 to 5 μm. By setting the above average particle diameter to 0.00 w μm or more, the wettability and adhesion of the thermosetting adhesive layer of the present invention are improved, which is preferable. Moreover, by setting the average particle diameter to 10 μm or less, the strength of the thermosetting adhesive layer of the present invention is improved, and the heat-resistant adhesive sheet of the present invention is improved in heat resistance after moist heat, which is preferable. Further, the average particle diameter of the filler can be determined, for example, by a photometric particle size distribution meter (device name "LA-910", manufactured by Horiba Seisakusho Co., Ltd.).

The above-mentioned cerium oxide filler or the above copper filler may also be subjected to surface treatment.

The thermosetting adhesive composition of the present invention preferably contains at least one of the above-described ceria filler and the above copper filler. That is, the thermosetting adhesive composition of the present invention may contain either a cerium oxide filler or a copper filler, or may contain only one of a cerium oxide filler and a copper filler.

In the thermosetting adhesive composition of the present invention, the total amount (the total content, the total content ratio, and the total blending ratio) of the content of the cerium oxide filler and the content of the copper filler is not particularly limited, and is polymerized with respect to acrylic acid. The object (X) is 100 parts by weight, preferably 1 to 150 parts by weight, more preferably 5 to 140 parts by weight, still more preferably 10 to 120 parts by weight. By setting the above content to 1 part by weight or more, the strength of the thermosetting adhesive layer of the present invention is improved, and the heat-resistant adhesive sheet of the present invention has improved heat resistance after moist heat. Again, by When the content is 150 parts by weight or less, the thermosetting adhesive layer of the present invention can be prevented from becoming brittle and the strength thereof can be lowered. Further, in the case where the thermosetting adhesive composition of the present invention contains either a cerium oxide filler or a copper filler, the content of the cerium oxide filler or the copper filler contained therein.

The thermosetting adhesive composition of the present invention preferably contains, for example, a C _1-14 alkyl (meth)acrylate (a), a cyano group-containing monomer (b), and a carboxyl group-containing monomer (c). The acrylic polymer (X) which is an essential monomer component is contained as a main component, and the etherified phenol resin (Y) is contained.

The thermosetting adhesive composition of the present invention can be produced, for example, by mixing an acrylic polymer (X), an etherified phenol resin (Y), and various additives as needed. Further, the acrylic polymer (X) or the etherified phenol resin (Y) may be in a state of being dissolved in a solvent to form a solution, or may be dispersed in a dispersion medium to form a dispersion. To prepare the thermosetting adhesive composition of the present invention.

[The thermosetting adhesive layer of the present invention]

The thermosetting adhesive layer of the present invention is a thermosetting adhesive layer formed from the thermosetting adhesive composition of the present invention. The thermosetting adhesive layer of the present invention may have any one of a single layer and a plurality of layers.

The thickness of the thermosetting adhesive layer of the present invention is 1 to 20 μm, preferably 5 to 20 μm, preferably 8 to 18 μm, more preferably 10 to 15 μm. It is preferable that the thickness is 1 μm or more and the force is increased. On the other hand, by the above thickness of 20 μm or less, even after the curing time is short, the heat-dissipating layer of the cured thermosetting adhesive layer is heat-dissipating, adhesive, and after damp heat Excellent heat resistance.

The thermosetting adhesive layer of the present invention is not particularly limited, and it is preferably a total thermal resistance (total thermal resistance measured by a stable heat flow method) of 2.0 (cm ² ) after curing at 150 ° C for 60 minutes. K)/W or less is more preferably 0.01 to 1.8 (cm ² .K)/W, further preferably 0.1 to 1.6 (cm ² .K)/W, and particularly preferably 0.3 to 1.5 (cm ² .K)/ W. That is, it is preferred that the total heat resistance after curing at 150 ° C for 60 minutes is 2.0 (cm ² .K) / W or less, more preferably 0.01 to 1.8 (cm ² .K) / W, and further preferably. It is 0.1 to 1.6 (cm ² .K)/W, and particularly preferably 0.3 to 1.5 (cm ² .K)/W. By the above-described total thermal resistance is 2.0 (cm ² .K) / W or less, after heat-curing the curable adhesive layer becomes heat radiation (thermal conductivity) are excellent, so the use of heat-curing of the present invention will next sheet In the case where the two are attached to the body, heat can be efficiently moved from one of the adherends to the other of the adherends. Specifically, for example, when the FPC and the reinforcing plate are brought together via the heat-set adhesive sheet of the present invention, the heat accumulated in the FPC can be efficiently transferred to the reinforcing plate via the heat-set adhesive sheet of the present invention. Cooling.

Furthermore, the term "total thermal resistance" refers to the total of the thermal resistance of the cured thermosetting adhesive layer itself and the contact thermal resistance. Further, the term "contact thermal resistance" means that air is interposed between the surface of the adhesive layer and the adherend due to the surface roughness of the thermosetting adhesive layer after curing, etc., whereby the adhesive layer is followed by The thermal resistance generated between the bodies. Further, the total thermal resistance can be measured by the method described in "(3) Total thermal resistance" (Evaluation) below.

The thermosetting adhesive layer of the present invention is not particularly limited, and from the viewpoint of heat dissipation, it is preferably a total thermal resistance after curing at 150 ° C for 20 minutes (total heat measured by a stable heat flow method) The resistance is 0.1 to 1.6 (cm ² .K)/W, more preferably 0.2 to 1.5 (cm ² .K)/W, and still more preferably 0.3 to 1.5 (cm ² .K)/W.

The gel fraction of the thermosetting adhesive layer (before curing) of the present invention is not particularly limited, and from the viewpoint of the flexibility of the thermosetting adhesive layer of the present invention, it is preferably less than 70% by weight. %) (for example, 0% or more and less than 70%), more preferably less than 60%, and even more preferably less than 50%. The above gel fraction can be determined in the form of a methyl ethyl ketone insoluble component, specifically, an insoluble component which can be immersed in methyl ethyl ketone at room temperature (23 ° C) for 7 days with respect to impregnation. The weight fraction (unit: weight %) of the former sample was determined. Since the gel fraction is less than 70%, the flexibility of the thermosetting adhesive layer of the present invention is improved and the force is increased, which is preferable.

Specifically, the gel fraction (the ratio of the methyl ethyl ketone insoluble component) can be measured and calculated, for example, by the following method for measuring the gel fraction.

<Method for measuring gel fraction>

From the thermosetting back sheet of the present invention, about 0.1 g of the thermosetting adhesive layer of the present invention was collected to prepare a thermosetting adhesive layer for gel fraction measurement. After the thermosetting adhesive layer for measuring the gel fraction was coated in a porous tetrafluoroethylene sheet (trade name "NTF1122", manufactured by Nitto Denko Corporation) having a pore diameter of 0.2 μm, The kite was bundled, and the weight at this time was measured, and the weight was set as the weight before immersion. Further, the pre-impregnation weight is a total weight of the thermosetting adhesive layer, the tetrafluoroethylene sheet, and the kite string. Further, the total weight of the tetrafluoroethylene sheet and the kite line was measured in advance, and the weight was set as the weight of the bag.

Next, the above-mentioned thermosetting type adhesive layer is wrapped with a sheet of tetrafluoroethylene and bundled with a kite string (referred to as "sample") to be fed to methyl ethyl group. The ketone-filled 50 mL container was allowed to stand at room temperature (23 ° C) for 1 week (7 days). Thereafter, the sample was taken out from the container (after treatment with methyl ethyl ketone), transferred to an aluminum cup, and dried in a dryer at 130 ° C for 2 hours to remove methyl ethyl ketone, and then the weight was measured. This weight was set as the weight after immersion.

Then, the gel fraction was calculated according to the following formula.

Gel fraction (% by weight) = (A-B) / (C-B) × 100 (In the above formula, A is the weight after immersion, B is the weight of the bag, and C is the weight before immersion).

The gel fraction of the thermosetting adhesive layer of the present invention after heat curing at 150 ° C for 1 hour is not particularly limited, but is preferably 90% by weight or more, more preferably 92% or more. It is preferably 96% or more. The upper limit of the gel fraction of the thermosetting adhesive layer of the present invention after heat curing at 150 ° C for 1 hour is not particularly limited and is, for example, 100%. When the gel fraction is 90% or more, the thermosetting treatment of the thermosetting adhesive layer of the present invention can be quickly and sufficiently performed, and the adhesion after thermosetting and the heat resistance after moist heat are more excellent. good. When the gel fraction is less than 90%, the thermosetting reaction is insufficient in the thermosetting treatment at 150 ° C for 1 hour, and the heat resistance after heat-sealing or insufficient heat resistance after moist heat is present. A situation in which the cost becomes high is sufficiently followed by a higher curing temperature or a longer curing time.

Further, specifically, the gel fraction of the thermosetting adhesive layer after heat curing at 150 ° C for 1 hour can be calculated, for example, by the following method: from the heat-set adhesive sheet of the present invention A thermosetting adhesive layer (cured thermosetting adhesive layer) was collected in a thermosetting adhesive sheet which was heated at 150 ° C for 1 hour and subjected to thermosetting treatment, and was referred to as "gel fraction". For measurement The thermosetting adhesive layer was measured in the same manner as the above <Method for Measuring Gel Fraction>.

[The thermosetting adhesive sheet of the present invention]

The thermoset adhesive sheet of the present invention has at least one layer of the thermosetting adhesive layer of the present invention (a thermosetting adhesive layer formed from the thermosetting adhesive composition of the present invention). In addition to the thermosetting adhesive layer of the present invention, the thermosetting adhesive sheet of the present invention may have a substrate, a thermosetting adhesive layer other than the thermosetting adhesive layer of the present invention, and the like. Further, other layers (for example, an intermediate layer, an undercoat layer, etc.) may be provided within the range in which the effects of the present invention are not impaired. The layers other than the thermosetting adhesive layer of the present invention may be provided in only one layer, or may be provided in two or more layers.

The thermosetting adhesive sheet of the present invention may be a single-sided adhesive sheet in which only one side of the sheet is the surface of the adhesive layer (the surface of the adhesive layer), that is, the surface of the thermosetting adhesive layer of the present invention. The both sides of the sheet are double-sided sheets of the surface of the adhesive layer (adhesive surface). The thermosetting adhesive sheet of the present invention is not particularly limited, and is preferably a double-sided back sheet, more preferably a double sheet, from the viewpoint of bonding the articles (attached bodies) to each other. The face is a double-sided backing sheet of the surface of the thermosetting adhesive layer.

The thermosetting adhesive sheet of the present invention may be a thermosetting adhesive sheet having a substrate (a thermosetting adhesive sheet with a substrate attached thereto) or a thermosetting adhesive sheet having no substrate ( Substrate-free thermoset type sheet). Examples of the thermosetting adhesive sheet of the present invention include (1) a thermosetting adhesive sheet comprising only the thermosetting adhesive layer of the present invention and having no substrate (substrate-free thermosetting type) Next, the sheet), (2) on at least one side of the substrate (double-sided side or single-sided side) Side) A thermosetting back sheet having a thermosetting adhesive layer of the present invention (a thermosetting back sheet to which a substrate is attached) or the like. The heat-resistant adhesive sheet of the present invention is preferably a substrate-free thermosetting adhesive sheet, wherein the above-mentioned (1) is preferable in terms of ease of manufacture and heat dissipation (thermal conductivity). A non-substrate thermoset type backsheet comprising only the thermosetting adhesive layer of the present invention and having no substrate. Further, the above-mentioned "substrate" does not contain a release liner (separator) which is peeled off when a heat-set type sheet is used.

Furthermore, in the case where the thermosetting adhesive sheet of the present invention is a thermosetting adhesive sheet to which a substrate is attached, the thermosetting adhesive layer of the present invention may be provided on at least one side of the substrate. . It is also possible to provide a thermosetting adhesive layer other than the thermosetting adhesive layer of the present invention, or a thermosetting type, on the side opposite to the side of the substrate on which the thermosetting adhesive layer of the present invention is provided. A known adhesive layer other than the agent layer [for example, an adhesive layer (pressure-sensitive adhesive layer) or the like].

The substrate is not particularly limited, and examples thereof include a paper base material such as paper; a fiber base material such as a cloth, a nonwoven fabric, or a mesh; a metal base material such as a metal foil or a metal plate; and various resins (polyolefin). Resin, polyester resin, polyvinyl chloride resin, vinyl acetate resin, polyamido resin, polyimide resin, polyether ether ketone (PEEK), polyphenylene sulfide (PPS), etc.) a rubber-based substrate such as a film or a sheet; a rubber-based substrate such as a rubber sheet; a foamed system substrate such as a foamed sheet; or a laminate of the above-mentioned laminates (especially a laminate of a plastic substrate and other substrates) Or a suitable sheet such as a plastic film (or sheet) laminated to each other.

The thickness of the substrate is not particularly limited, but is preferably from 10 to 150 μm, more preferably from 10 to 100 μm, from the viewpoint of workability, and further preferably 10~50 μm. Further, the substrate may have a single layer form or a plurality of layers. Further, various treatments such as back treatment, antistatic treatment, and primer treatment may be applied to the substrate as needed.

The thermosetting back sheet of the present invention may be in the form of being wound into a roll or laminating a sheet. That is, the thermosetting back sheet of the present invention may have a form such as a sheet shape or a belt shape. Further, in the case where the thermosetting adhesive sheet of the present invention has a form of being wound into a roll, for example, the thermosetting adhesive layer may be a release treatment by a release liner or a back side formed on the substrate. In the state of layer protection, it is wound into a roll shape.

The surface of the adhesive layer (e.g., the thermosetting adhesive layer of the present invention) in the thermosetting adhesive sheet of the present invention may also be protected by a release liner (separator). The release liner is not particularly limited, and can be appropriately selected from known release liners. As the release liner, for example, a release liner having a surface treated with a ketone on a substrate (pad substrate) such as a paper or a plastic film, or a substrate such as a paper or a plastic film (pad substrate) is preferable. A release liner in which the surface is laminated with a polyolefin resin. The polyolefin resin is not particularly limited, and is preferably a polyethylene resin.

The thickness of the thermosetting back sheet of the present invention is not particularly limited, but is preferably 190 μm or less (4 to 190 μm), more preferably 140 μm or less (4 to 140 μm), still more preferably 90 μm or less. When the thickness is 190 μm or less, the total heat resistance of the thermosetting sheet of the present invention is low, and the heat dissipation property is excellent.

The thermosetting back sheet of the present invention can be produced in accordance with a known or conventional method of producing a sheet. For example, in the case where the thermosetting adhesive sheet of the present invention is a substrateless thermosetting adhesive sheet, the present method can be used to form the present invention. The thermosetting adhesive sheet of the present invention is produced by applying the thermosetting adhesive layer of the present invention: the thermosetting adhesive composition of the present invention is applied to the release surface of the release liner in such a manner that the thickness after drying becomes a predetermined thickness. Top and let it dry.

In the case where the thermosetting adhesive sheet of the present invention is a thermosetting adhesive sheet to which a substrate is attached, the thermosetting adhesive sheet of the present invention can be produced by the following method: in the same manner as above After forming the thermosetting adhesive layer of the present invention on the release surface of the release liner, the thermosetting adhesive layer is transferred onto the surface of the substrate. Further, the thermosetting adhesive sheet of the present invention can be produced by forming the thermosetting adhesive layer of the present invention by the following method: the thickness of the thermosetting adhesive composition of the present invention becomes a predetermined thickness after drying. The method is applied to the surface of the substrate and allowed to dry.

Further, when applying the thermosetting adhesive composition of the present invention, a conventional coating machine (for example, a gravure roll coater, a reverse roll coater, a contact roll coater, a dip roll coater) can be used. , bar coater, knife coater, spray roll coater, etc.).

The thermosetting adhesive sheet of the present invention and the thermosetting adhesive layer of the present invention are subjected to a curing reaction (thermosetting) by heating, whereby an excellent adhesion can be exerted. By heating the thermosetting adhesive sheet of the present invention to cure (thermoset) the thermosetting adhesive layer of the present invention, an adhesive sheet having a strong adhesive force can be obtained (thermosetting thermosetting adhesive sheet) ).

The curing temperature in the thermosetting is not particularly limited, but is preferably 100 ° C or higher (for example, 100 to 200 ° C), and more preferably 140 ° C or higher (for example, 140 to 200 ° C, preferably 140 to 170 ° C). More preferably, it is 150 ° C or more (for example, 150 to 170 ° C).

The curing time in the above thermosetting is not particularly limited, but is preferably less than 60 minutes (for example, 20 minutes or more and less than 60 minutes), more preferably less than 30 minutes (for example, 20 minutes or more and less than 30 minutes). ). Even if the curing time is less than 60 minutes, the cured thermosetting adhesive layer of the present invention after curing and the cured thermosetting adhesive sheet of the present invention after curing can exhibit excellent adhesion, heat resistance after heat and heat, and heat dissipation. Further, in the laminated body having the thermosetting back sheet of the present invention on the FPC, the heat accumulated in the FPC can be efficiently dissipated. In particular, even when the curing time is as short as less than 30 minutes, excellent adhesion, heat resistance after damp heat, and heat dissipation can be exhibited. Therefore, for example, in the case of use in a manufacturing use of a product requiring excellent heat resistance and heat dissipation after wet heat such as FPC, the production efficiency is improved.

The curing conditions (heating conditions) are not particularly limited, but are preferably not more than 60 minutes at a temperature of 100 ° C or higher (for example, 100 to 200 ° C) (for example, 20 minutes or more and less than 60 minutes, preferably 20 minutes). Heating above, but not more than 30 minutes, more preferably at a temperature of 140 ° C or higher (for example, 140 to 200 ° C, preferably 140 to 170 ° C) for less than 60 minutes (for example, 20 minutes or more and less than 60 minutes, Preferably, it is heated for more than 20 minutes and less than 30 minutes, and more preferably at a temperature of 150 ° C or higher (for example, 150 to 170 ° C) for less than 60 minutes (for example, 20 minutes or more and less than 60 minutes, preferably Heating for more than 20 minutes and less than 30 minutes).

The thermosetting adhesive composition of the present invention has a high adhesion (adhesion) because it contains the acrylic polymer (X). Further, since the thermosetting adhesive composition of the present invention contains the etherified phenol resin (Y), the thermosetting adhesive composition of the present invention is easily cured by heating and has excellent thermosetting properties, and further adhesive force. And after heat and humidity, it is excellent in heat resistance.

In addition, since the thermosetting adhesive sheet of the present invention has a thickness of 1 to 20 μm due to the thermosetting adhesive layer, even after the curing time is short, the cured thermosetting adhesive layer is followed. It is excellent in heat resistance after heat and humidity, and has low total heat resistance and excellent heat dissipation (thermal conductivity).

The heat-curable adhesive sheet of the present invention can exhibit high adhesion after curing, excellent heat resistance after moist heat, and excellent heat dissipation even if the curing time is short. Therefore, the thermosetting back sheet of the present invention is firmly adhered to, and can be preferably used in the following applications and the like: it is required to be foamed or floated even after being subjected to treatment under extremely severe temperature conditions. It is excellent in heat resistance after peeling and the like, and is used for the purpose of imparting excellent thermal conductivity in order to dissipate the heat of the adherend. Specifically, the thermosetting back sheet of the present invention can be preferably used, for example, in the following in a flexible printed circuit board (FPC). That is, the thermosetting back sheet of the present invention is preferably a thermosetting back sheet for FPC. In addition, the subsequent FPC refers to, for example, the subsequent step of fabricating the FPC or attaching the FPC to the reinforcing plate.

In most cases, the FPC is passed through a high temperature reflow step prior to being incorporated into the final article, so that the thermoset type of sheet used does not require foaming or floating peeling after the reflow step. Further, in many cases, the FPC inside the electronic device has heat, and therefore heat dissipation (thermal conductivity) is required for the adhesive (the sheet) used in the subsequent FPC. In the use of such FPCs, "heat resistance after damp heat" and "heat dissipation" are highly valued from the viewpoint of reliability. In addition, the term "heat resistance after moist heat" refers to a laminate produced by using a thermosetting sheet followed by a binder under high temperature and high humidity. (For example, when the temperature is 40 to 60 ° C and the humidity is 60 to 95% RH), the heat is stored in a severe temperature condition (for example, at a temperature of 250 to 270 ° C for 1 to 3 minutes). In the solid form-fed sheet (thermosetting type adhesive layer), the characteristics of foaming or lifting and peeling are also less likely to occur.

The thermosetting adhesive sheet of the present invention can exhibit high heat resistance after heat setting and excellent heat resistance after damp heat, and can exhibit heat dissipation, so that it can be used as a highly reliable heat in FPC applications. The solid form follows the sheet. That is, by producing the FPC using the thermosetting back sheet of the present invention, an FPC having the thermosetting back sheet of the present invention can be obtained.

The method for producing the FPC having the thermosetting back sheet of the present invention by using the thermosetting back sheet of the present invention is not particularly limited, and for example, the conductive metal foil is bonded using the thermosetting back sheet of the present invention. A method of producing an FPC by laminating on a heat resistant substrate.

The heat-resistant substrate is not particularly limited, and examples thereof include a base material made of polyimide and a base material made of polyamide. The conductive metal foil is not particularly limited, and examples thereof include a copper foil and an aluminum foil.

Further, by laminating the FPC and the reinforcing sheet using the thermosetting back sheet of the present invention, a laminate having the thermosetting sheet of the present invention on the FPC can be obtained. That is, the thermosetting back sheet of the present invention can be used in a method of bonding an FPC to a reinforcing sheet via (using) the thermosetting back sheet of the present invention, and manufacturing the FPC with the thermosetting type of the present invention. Sheet laminate (FPC with reinforcing plate).

The method of producing the laminate of the thermosetting adhesive sheet of the present invention on the FPC is not particularly limited, and examples thereof include the following methods: FPC or reinforcement. The thermosetting adhesive sheet of the present invention is attached to the board, and the FPC or the reinforcing sheet is subsequently produced on the FPC via a thermosetting thermosetting sheet obtained by thermosetting the thermosetting sheet. A laminate of the thermosetting sheet of the present invention. The laminate having the thermosetting adhesive sheet of the present invention on the FPC can be bonded to the entire surface of the FPC (or reinforcing plate) using the thermosetting adhesive sheet of the present invention, and the thermosetting type of the present invention can also be used. The sheet is then applied to one of the FPC (or reinforcing sheets). Further, the laminate having the thermosetting-type back sheet of the present invention on the FPC may be provided with a film or a plate (another substrate or a light shielding plate or the like) within a range not deteriorating the effects of the present invention. Further, the FPC may be an FPC manufactured using the thermosetting adhesive sheet of the present invention, or may be a well-known or conventional FPC.

The reinforcing plate is not particularly limited, and examples thereof include an aluminum plate, a stainless steel plate (such as a stainless steel plate), and a polyimide plate. Among them, a stainless steel plate or a polyimide plate is preferred.

The laminate having the thermosetting adhesive sheet of the present invention on the FPC can be obtained by thermosetting the thermosetting adhesive sheet of the present invention to obtain a heat-set type having heat dissipation, adhesion, and heat resistance after wet heat. A laminate of sheets (having a thermoset thermoset followed by a laminate of sheets on the FPC). Further, the thermosetting condition of the thermosetting sheet in the laminate can be carried out under the same conditions as those of the above-described thermosetting sheet of the present invention.

Example

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples.

In Table 1, the acrylic polymer (X) in the examples and comparative examples is shown. The monomer composition, the content in the thermosetting adhesive composition (the amount of the formulation), the content in the thermosetting adhesive composition of the etherified phenol resin (Y) (the amount of the formulation), and the thermosetting adhesive layer thickness. In addition, in Table 1, the monomer composition of the acrylic polymer (X) is the content (weight) of each monomer in the total amount (100% by weight) of the monomer components constituting the acrylic polymer (X). %) indicates. Further, the content of the acrylic polymer (X) and the etherified phenol resin (Y) is represented by the content (parts by weight) of the nonvolatile component.

(Example 1) (Preparation of acrylic polymer (X))

In a reactor equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer, 2,2'-azobis{2-[1-(2-hydroxyethyl)-2-imidazolin-2-yl]propane was charged. } Dihydrochloride (trade name "VA-060", manufactured by Wako Pure Chemical Industries, Ltd.) (polymerization initiator) 0.279 g, 100 g of ion-exchanged water, and stirred while introducing nitrogen gas for 1 hour. This was kept at 60 ° C, and 66 parts by weight of butyl acrylate (n-butyl acrylate) (BA), 29 parts by weight of acrylonitrile (AN), and 5 parts by weight of acrylic acid (AA) were gradually added dropwise thereto over 3 hours. 0.04 parts by weight of 1-dodecanethiol (chain transfer agent) and 2 parts by weight of sodium polyoxyethylene lauryl ether sulfate (emulsifier) are added to 41 parts by weight of ion-exchanged water to be emulsified (monomer raw material) The emulsion was 400 g and subjected to emulsion polymerization. After the dropwise addition of the emulsion of the monomer raw material, the temperature was maintained at this temperature for 3 hours to carry out aging. The aqueous dispersion (emulsion) of the acrylic polymer polymerized in this manner was dried to obtain an acrylic polymer (X) (weight average molecular weight: 1,000,000).

(Preparation of thermosetting adhesive composition)

The above-mentioned acrylic polymer (X) [copolymer composed of 66% by weight of butyl acrylate (BA), 29% by weight of acrylonitrile (AN), and 5% by weight of acrylic acid (AA) as a monomer component] was dissolved. A butanol solution of 12 parts by weight (nonvolatile matter) of the trade name "CKS-3898" (manufactured by Showa Denko Co., Ltd.) as an etherified phenol resin (Y) was mixed and dissolved in an ethyl acetate solution of the weight fraction and stirred. A thermosetting adhesive composition (solution) was prepared.

That is, the thermosetting adhesive composition contains 100 parts by weight of the acrylic polymer (X) and 12 parts by weight of the etherified phenol resin (Y).

(The manufacture of thermosetting type sheets)

The thermosetting adhesive composition was applied to a release surface of a release liner so as to have a thickness of 5 μm after drying, and dried at 100 ° C for 3 minutes to form a thermosetting adhesive layer (thickness: 5 μm). A thermosetting back sheet (substrate-free thermosetting sheet comprising only a thermosetting type of adhesive layer) was obtained.

(Example 2)

A thermosetting adhesive composition and a thermosetting adhesive sheet were obtained in the same manner as in Example 1 except that the thickness of the thermosetting adhesive layer was changed to 13 μm as shown in Table 1.

(Comparative Example 1)

As shown in Table 1, a thermosetting adhesive composition and a thermosetting adhesive sheet were obtained in the same manner as in Example 1 except that the thickness of the thermosetting adhesive layer was changed to 25 μm.

(Comparative Example 2)

A thermosetting adhesive combination was obtained in the same manner as in Example 1 except that the thickness of the thermosetting adhesive layer was changed to 35 μm as shown in Table 1. And the thermosetting type followed by the sheet.

(Evaluation)

For each of the thermosetting back sheets obtained in the examples and the comparative examples, the adhesion force after curing of the thermosetting adhesive layer, heat resistance after damp heat, and total heat were measured or evaluated by the following measurement methods or evaluation methods. Resistance.

(1) Method of measuring the force

The adhesion (N/cm) at 23 ° C of the cured thermosetting adhesive layer in each of the thermosetting back sheets obtained in the examples and the comparative examples was measured by the following method.

A flexible printed circuit board (FPC, size: width 5 cm × length 8 cm, thickness 0.2 mm) and a thermosetting back sheet were laminated at 130 ° C and cut into a width of 1 cm (thermoset type sheet) It is laminated on the single side of the FPC (the surface of the material: polyimine). It was laminated to a stainless steel plate (SUS304BA plate) (SUS, size: length 5 cm × width 5 cm, thickness 0.4 mm) at 130 ° C using a laminator, and then heated at 160 ° C, 2 MPa for 90 seconds. Crimp (pressurized) and attached. Further, a sample was prepared by curing (heat curing) at 150 ° C for 20 minutes.

By using a tensile tester (product name "TCM-1kNB", manufactured by Minebea Co., Ltd.), the above sample was stretched on the FPC side, and the 90° peeling adhesion force was measured (stretching speed: 50 mm/min, 23 ° C, 50% RH, N / cm).

In addition, the measurement results are shown in the column of "adhesion force (N/cm) curing for 20 minutes SUS" in Table 1.

Moreover, in the above measurement, it was produced by curing at 150 ° C for 60 minutes. For the sample, the 90° peeling adhesion force was measured in the same manner. The measurement results are shown in the column of "adhesion force (N/cm) curing for 60 minutes SUS" in Table 1.

Further, in the above measurement, a polyimide plate (PI: size: length: 5 cm × width: 5 cm, thickness: 0.13 mm) was used instead of the stainless steel plate, and the 90° peeling adhesion force was measured in the same manner.

The measurement results are shown in the column of "adhesion force (N/cm) curing for 20 minutes PI" and "adjacent force (N/cm) curing for 60 minutes PI" in Table 1.

(2) Evaluation method of heat resistance after damp heat (immersion in solder at 260 ° C after humidification)

The heat-curing heat-resistant adhesive layer in each of the thermosetting back sheets obtained in the examples and the comparative examples was evaluated for heat resistance after moist heat.

A copper clad laminate (CCL; polyimine/copper laminate, size: width 5 cm × length 8 cm, thickness 45 μm) and thermosetting sheet were laminated at 130 ° C and cut into 1 cm The wide (thermoset type sheet is laminated on the entire surface of the polyacrylamide surface of CCL). It was laminated to a stainless steel plate (SUS304BA plate) (SUS, size: length 5 cm × width 5 cm, thickness 0.4 mm) at 130 ° C using a laminator, and then heated at 160 ° C, 2 MPa for 90 seconds. Crimp (pressurized) and attached. Further, a sample was prepared by curing (heat curing) at 150 ° C for 20 minutes.

The sample was allowed to stand under the conditions of heat and humidity (temperature: 60 ° C, humidity: 90% RH) for 24 hours, and then the surface of the stainless steel plate side of the sample was dipped in a solder bath at 260 ° C for 3 minutes. .

The state of floating and peeling and foaming of the cured thermosetting adhesive layer in the above sample was visually observed, and the heat resistance after moist heat was evaluated according to the following criteria. again The evaluation results are shown in the column of "heat-resistant heat-curing after 20 minutes of SUS" in Table 1.

In addition, the heat resistance after moist heat was evaluated in the same manner as above except that the heat curing was performed at 150 ° C for 60 minutes. In addition, the evaluation results are shown in the column of "heat-resistant curing after heat-heating for 60 minutes SUS" in Table 1.

Excellent heat resistance after moist heat (○): No peeling and foaming were observed in the thermosetting adhesive layer.

After the heat of dampness, the heat resistance was slightly deteriorated, but (Δ): floating peeling and foaming were confirmed in a part of the thermosetting adhesive layer.

Heat resistance deterioration after wet heat (×): Floating peeling and foaming were confirmed on the entire surface of the thermosetting adhesive layer.

Further, in the above evaluation, heat resistance after moist heat was evaluated in the same manner using a polyimide plate (PI, size: length 5 cm × width 5 cm, thickness 0.13 mm) instead of the stainless steel plate. The evaluation results are shown in the column of "heat-resistant post-heating curing for 20 minutes PI" and "heat-heat-hardening after curing for 60 minutes PI" in Table 1.

(3) Total thermal resistance

The total thermal resistance at 80 ° C was measured for the cured thermosetting adhesive layers in the respective thermosetting back sheets obtained in the examples and the comparative examples.

The measurement was carried out using the thermal property evaluation device shown in Fig. 1 . Fig. 1(a) is a front schematic view showing the apparatus used for measuring the total thermal resistance in the embodiment, and Fig. 1(b) is a schematic side view showing the apparatus shown in Fig. 1(a).

Specifically, it is shaped like a cube with a side of 20 mm. A pair of aluminum (A5052, thermal conductivity: 140 W/m.K) rod L is sandwiched between a thermosetting type and then a sheet S (20 mm × 20 mm), and a pair of thermosetting type sheets S are used. The rod L fits.

Then, the rod L is disposed between the heat generating body (heat generating block) H and the heat radiating body (the cooling floor plate configured to circulate the inside of the cooling water) C with the pair of rods L being turned up and down. Specifically, the heating element H is disposed on the upper rod L, and the radiator C is disposed below the lower rod L.

At this time, the pair of rods L which are bonded by the thermosetting thermosetting type sheet S are located between the pair of pressure adjusting screws T penetrating the heating element H and the radiator C. Further, a load cell R is provided between the pressure adjusting screw T and the heating element H, and the pressure at the time of tightening the pressure adjusting screw T is measured, and the above pressure is applied as a thermosetting type. The pressure of the sheet S.

Further, three probes P (having a diameter of 1 mm) of the contact type displacement meter were provided so as to penetrate the lower rod L from the heat sink C side and the thermosetting thermosetting sheet S. At this time, the upper end portion of the probe P is in contact with the lower surface of the upper rod L, so that the interval between the upper and lower rods L (the thickness of the thermosetting thermosetting type sheet S) can be measured. .

A temperature sensor D is attached to the heating element H and the upper and lower rods L (see Fig. 1(b)). Specifically, a temperature sensor D is attached to one of the heat generating bodies H, and the temperature sensor D is mounted at five places at intervals of 5 mm along the upper and lower directions of the respective rods L.

First, the pressure adjusting screw T is tightened, pressure is applied to the thermosetting thermosetting sheet S, the temperature of the heating element H is set to 80 ° C, and the cooling water of 20 ° C is circulated in the radiator C.

Then, after the temperature of the heating element H and the upper and lower rods L are stabilized, the temperature of the upper and lower rods L is measured by each temperature sensor D, and the thermosetting thermosetting is calculated based on the thermal conductivity and the temperature gradient of the upper and lower rods L. The type is followed by the heat flux of the sheet S, and the temperature of the interface between the upper and lower rods L and the thermosetting thermosetting sheet S is calculated. Then, the total thermal resistance (cm ² .K)/W at the pressure was calculated using these. Further, the total heat resistance was measured by setting the pressure applied to the thermosetting heat-curable back sheet S to 250 kPa.

Further, the measurement results are shown in the column of "Total thermal resistance (cm ² .K) / W curing for 20 minutes" in Table 1.

Further, in the above measurement, the total heat resistance was measured in the same manner using a thermosetting thermosetting back sheet which was heat-cured at 150 ° C for 60 minutes. The measurement results are shown in the column of "Total Thermal Resistance (cm ² .K) / W Curing for 60 Minutes" in Table 1.

As is clear from Table 1, the thermosetting adhesive sheet of the present invention has a high adhesion after curing and excellent adhesion even when the thermosetting time is as short as 20 minutes, and further, even under humidified heat conditions. When the solder impregnation treatment was carried out under severe temperature conditions (260 ° C), no floating peeling or foaming was observed, and the heat resistance after moist heat was high. Further, even if the curing time is short, the total heat resistance of the thermosetting adhesive layer after curing is low, and the heat dissipation property (thermal conductivity) is excellent (Examples 1 and 2).

On the other hand, a thermosetting adhesive sheet having a thermosetting adhesive layer having a thickness of 20 μm thick is subjected to solder impregnation under severe temperature conditions after being placed under humidified heat conditions in a case where the curing time is short. In the case of the treatment, floating peeling or foaming is observed in the thermosetting adhesive layer, and heat resistance is deteriorated after moist heat. Further, the thermosetting adhesive layer having a thickness of 20 μm thick has a higher total heat resistance and deteriorates heat dissipation (thermal conductivity) (Comparative Examples 1 and 2).

Industrial use possibility

The thermosetting back sheet of the present invention exhibits excellent adhesion, heat resistance after moist heat, and excellent thermal conductivity even when the curing time is short. Therefore, the thermosetting adhesive sheet of the present invention is firmly adhered to, and can be preferably used for the following use of the following flexible printed circuit board (FPC), etc., which is required to be used even under extremely severe temperature conditions. In the case of the treatment, excellent heat resistance after moist heat such as foaming or lifting and peeling is not caused, and excellent heat conductivity is required in order to dissipate the heat of the adherend.

C‧‧‧heat radiator

D‧‧‧Temperature Sensor

H‧‧‧heating body

L‧‧‧ rod

P‧‧‧ probe

R‧‧‧ load weight

S‧‧‧ Thermoset thermoset sheet

T‧‧‧Pressure adjustment screw

Fig. 1(a) is a front schematic view of the apparatus used for measuring the total thermal resistance in the embodiment, and (b) is a schematic side view of the apparatus shown in (a).

Claims (10)

A thermosetting adhesive sheet comprising a thermosetting adhesive layer formed of a thermosetting adhesive composition, and the thermosetting adhesive composition comprising an acrylic polymer (X) as a main component The component contains an etherified phenol resin (Y), and the thickness of the above-mentioned thermosetting adhesive layer is 1 to 20 μm. The heat-set adhesive sheet according to claim 1, wherein the total heat resistance of the thermosetting adhesive layer after curing at 150 ° C for 60 minutes is 2.0 (cm ² .K) / W or less. The heat-set adhesive sheet according to claim 1 or 2, wherein the acrylic polymer (X) is an alkyl (meth)acrylate having a linear or branched alkyl group having 1 to 14 carbon atoms ( a) An acrylic polymer composed of an essential monomer component. The thermosetting adhesive sheet according to claim 3, wherein the acrylic polymer (X) further comprises a cyano group-containing monomer (b) and a carboxyl group-containing monomer (c) as essential monomer components. Acrylic polymer. The thermosetting back sheet according to any one of claims 1 to 4, wherein the content of the etherified phenol resin (Y) is from 1 to 40 parts by weight based on 100 parts by weight of the acrylic polymer (X). The thermosetting back sheet according to any one of claims 1 to 5, which comprises only the above-mentioned thermosetting type adhesive layer and does not have a substrate. The thermosetting adhesive sheet according to any one of claims 1 to 6, which is a thermosetting adhesive sheet for a flexible printed circuit board. A laminate body having a request on a flexible printed circuit board The heat-set type of the item 7 is followed by the sheet. A thermosetting thermosetting back sheet obtained by thermosetting a heat-set back sheet according to any one of claims 1 to 7. A laminate comprising a thermoset thermoset sheet as claimed in claim 9 on a flexible printed circuit board.