JP7120497B1 - Adhesive composition, and adhesive sheet, laminate and printed wiring board containing same - Google Patents

Abstract

[PROBLEMS] To provide an adhesive composition excellent in heat resistance, adhesive strength, low relative permittivity and dielectric loss tangent, and excellent dielectric properties, and an adhesive sheet, laminate, and printed wiring board containing the same. Kind Code: A1 An adhesive composition comprising an acid-modified resin, a compound A and a compound B. Compound A: A compound having a terminal unsaturated hydrocarbon group and having a 5% weight loss temperature of 260°C or higher Compound B: A compound having an epoxy group and a terminal unsaturated hydrocarbon group [Selection] None

Description

The present invention relates to adhesive compositions. More particularly, it relates to an adhesive composition used for bonding a resin base material and a resin base material or a metal base material. In particular, it relates to an adhesive composition for flexible printed wiring boards (hereinafter abbreviated as FPC), and adhesive sheets, laminates and printed wiring boards containing the same.

FPC has excellent flexibility, so it can be used for multi-functionality and miniaturization of personal computers (PCs) and smartphones. . In recent years, electronic devices have become smaller, lighter, denser, and higher in output, and the demand for the performance of wiring boards (electronic circuit boards) has become more and more sophisticated. In particular, high-frequency signals are being used to increase the transmission speed in FPC. Along with this, FPCs are increasingly required to have low dielectric properties (low dielectric constant, low dielectric loss tangent) in a high frequency region. In order to achieve such low dielectric properties, measures have been taken to reduce the dielectric loss of FPC substrates and adhesives. In addition to PET), base films such as liquid crystal polymer (LCP) and syndiotactic polystyrene (SPS) having low dielectric properties have been proposed. As adhesives, the development of a combination of polyolefin and epoxy (Patent Document 1), etc., and the development of adhesives using polyphenylene ether (Patent Document 2), etc. are underway.

WO2016/047289 WO2020/196718

However, the adhesive described in Patent Document 1 has high polarity because it contains an epoxy resin and an epoxy resin curing agent, and cannot satisfy the high requirements for dielectric loss tangent in particular. In addition, it is difficult to say that the adhesive described in Patent Document 2 has excellent heat resistance as an FPC adhesive, and its dielectric properties are also insufficient.

The present invention has been made against the background of such conventional technical problems. That is, an object of the present invention is to provide an adhesive composition having excellent heat resistance, adhesive strength, low dielectric constant and dielectric loss tangent, and excellent dielectric properties, and an adhesive sheet, a laminate and a printed wiring board containing the same. It is to be.

As a result of intensive studies, the inventors of the present invention have found that the above problems can be solved by means shown below, and have completed the present invention.
That is, the present invention consists of the following configurations.

[1] An adhesive composition comprising an acid-modified resin, compound A and compound B.
Compound A: a compound having a terminal unsaturated hydrocarbon group and a 5% weight loss temperature of 260°C or higher Compound B: a compound having an epoxy group and a terminal unsaturated hydrocarbon group [2] acid-modified resin The adhesive composition of [1] above, containing at least one resin selected from acid-modified polyolefins, acid-modified polystyrene resins and acid-modified cycloolefin polymers.
[3] The adhesive composition of [1] or [2], wherein the compound A is a compound having an aromatic ring structure or an alicyclic structure as a structural unit.
[4] The adhesive composition of [1] or [2] above, wherein the compound A is a polyphenylene ether or phenolic resin having a terminal unsaturated hydrocarbon group.
[5] The adhesive composition according to [1] to [4], wherein the compound B is a compound having an isocyanuric ring.
[6] An adhesive sheet having an adhesive layer comprising the adhesive composition of [1] to [5].
[7] A laminate having an adhesive layer comprising the adhesive composition of [1] to [5].
[8] A printed wiring board comprising the laminate of [7] as a component.

The adhesive composition of the present invention is excellent in dielectric properties, adhesive strength and solder heat resistance. Therefore, it is suitable for printed wiring board adhesives, adhesive sheets, laminates and printed wiring boards in the high frequency range.

One embodiment of the present invention will be described in detail below. However, the present invention is not limited to this, and can be implemented in various modifications within the scope described above.

<Acid-modified resin>
The acid-modified resin used in the present invention is a resin modified with an acid component. By using an acid-modified resin, it has excellent adhesion to metal substrates such as copper foil, and an adhesive layer having excellent solder heat resistance can be formed by a cross-linking reaction with an epoxy group of compound B described later.

The acid-modified resin used in the present invention can be prepared, for example, by modifying a base resin with an unsaturated carboxylic acid component, or by copolymerizing an unsaturated carboxylic acid component during polymerization of the base resin. . The unsaturated carboxylic acid component is not particularly limited, and includes acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, maleic anhydride, itaconic anhydride, and fumaric anhydride.

The lower limit of the acid value of the acid-modified resin used in the present invention is preferably 10 equivalents/10 ⁶ g or more, more preferably 20 equivalents, from the viewpoint of heat resistance and adhesiveness to resin substrates and metal substrates. /10 ⁶ g or more, more preferably 30 equivalents/10 ⁶ g or more. When it is at least the above value, the compatibility with the compound B and the like is improved, the adhesive strength is improved, and the crosslink density is increased, so that the heat resistance can be improved. The upper limit is preferably 1000 equivalents/10 ⁶ g or less, more preferably 700 equivalents/10 ⁶ g or less, and even more preferably 500 equivalents/10 ⁶ g or less. When it is the above value or less, adhesiveness and low dielectric properties become better.

The number average molecular weight (Mn) of the acid-modified resin used in the present invention is preferably in the range of 10,000 to 50,000. It is more preferably in the range of 15,000 to 45,000, still more preferably in the range of 20,000 to 40,000, and particularly preferably in the range of 22,000 to 38,000. By making it more than the said lower limit, cohesive force becomes favorable and can express the outstanding adhesiveness. Further, when the content is equal to or less than the above upper limit, excellent fluidity and good operability can be obtained.

The acid-modified resin used in the present invention is preferably an acid-modified resin obtained by acid-modifying a resin mainly composed of hydrocarbons, since it has good low dielectric properties. Olefin polymers and acid-modified polyolefins are preferred. Furthermore, from the viewpoint of pot life, acid-modified polystyrene resins and acid-modified cycloolefin polymers are preferred. The acid-modified resin can be used singly or in combination of two or more.

The acid-modified resin of the present invention preferably has a dielectric constant (εc) of 2.7 or less at a frequency of 10 GHz. It is more preferably 2.6 or less, still more preferably 2.3 or less. Although the lower limit is not particularly limited, it is practically 2.0. Also, the dielectric constant (εc) in the entire frequency range of 1 GHz to 60 GHz is preferably 2.7 or less, more preferably 2.6 or less, and even more preferably 2.3 or less.

The acid-modified resin of the present invention preferably has a dielectric loss tangent (tan δ) of 0.003 or less at a frequency of 10 GHz. It is more preferably 0.0025 or less, and still more preferably 0.002 or less. Although the lower limit is not particularly limited, it is practically 0.0001 or more. Further, the dielectric loss tangent (tan δ) in the entire frequency range of 1 GHz to 60 GHz is preferably 0.003 or less, more preferably 0.0025 or less, and even more preferably 0.002 or less.

The content of the acid-modified resin in the adhesive composition of the present invention is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 40% by mass or more. Moreover, it is preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. Within the above range, the adhesiveness and heat resistance are improved, which is preferable.

<Acid-modified polyolefin>
In the present invention, acid-modified polyolefin can be preferably used as the acid-modified resin. Although the acid-modified polyolefin used in the present invention is not limited, it is preferably obtained by grafting at least one of an α,β-unsaturated carboxylic acid and its acid anhydride to a polyolefin resin. Polyolefin resin refers to homopolymerization of olefin monomers exemplified by ethylene, propylene, butene, butadiene, isoprene, etc., or copolymerization with other monomers, and hydrocarbons such as hydrides and halides of the resulting polymers. It refers to a polymer mainly composed of a skeleton. The acid-modified polyolefin is preferably obtained by grafting at least one of α,β-unsaturated carboxylic acid and its acid anhydride to at least one of polyethylene, polypropylene and propylene-α-olefin copolymer. .

The propylene-α-olefin copolymer is mainly composed of propylene and is copolymerized with an α-olefin. As the α-olefin, for example, one or several of ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate and the like can be used. Among these α-olefins, ethylene and 1-butene are preferred. The ratio of the propylene component to the α-olefin component in the propylene-α-olefin copolymer is not limited, but the propylene component is preferably 50 mol% or more, more preferably 70 mol% or more.

Examples of at least one α,β-unsaturated carboxylic acid and its acid anhydride include maleic acid, itaconic acid, citraconic acid and their acid anhydrides. Among these, acid anhydrides are preferred, and maleic anhydride is more preferred. Specifically, the acid-modified polyolefins include maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, and maleic anhydride-modified propylene-ethylene-butene copolymer. Such acid-modified polyolefins can be used singly or in combination of two or more.

The lower limit of the acid value of the acid-modified polyolefin is preferably 89 equivalents/10 ⁶ g or more, more preferably 107 equivalents/10 ⁶ g, from the viewpoint of heat resistance and adhesiveness to resin substrates and metal substrates. or more, more preferably 125 equivalents/10 ⁶ g or more. By adjusting the content to the above lower limit or more, the compatibility with the compound B is improved, and excellent adhesive strength can be exhibited. Moreover, the crosslink density is high and the solder heat resistance is improved. The upper limit is preferably 713 equivalents/10 ⁶ g or less, more preferably 534 equivalents/10 ⁶ g or less, and even more preferably 356 equivalents/10 ⁶ g or less. Adhesiveness becomes favorable by making it below the said upper limit. Moreover, the viscosity and stability of the solution are improved, and excellent pot life can be exhibited. Furthermore, manufacturing efficiency is also improved.

The acid-modified polyolefin is preferably crystalline acid-modified polyolefin. The term "crystallinity" as used in the present invention means that the temperature is raised from -100°C to 250°C at a rate of 20°C/min using a differential scanning calorimeter (DSC), and a distinct melting peak is exhibited during the heating process. Point.

The melting point (Tm) of the acid-modified polyolefin is preferably in the range of 50°C to 120°C. It is more preferably in the range of 60°C to 100°C, and most preferably in the range of 70°C to 90°C. When the content is at least the above lower limit, the cohesive force derived from the crystals is improved, and excellent adhesiveness and solder heat resistance can be exhibited. Further, when the content is equal to or less than the upper limit, excellent solution stability and fluidity are obtained, and operability at the time of adhesion is improved.

The heat of fusion (ΔH) of the acid-modified polyolefin is preferably in the range of 5 J/g to 60 J/g. More preferably in the range of 10 J/g to 50 J/g, most preferably in the range of 20 J/g to 40 J/g. When the content is at least the above lower limit, the cohesive force derived from the crystals is improved, and excellent adhesiveness and solder heat resistance can be exhibited. Further, when the content is equal to or less than the upper limit, excellent solution stability and fluidity are obtained, and operability at the time of adhesion is improved.

The method for producing the acid-modified polyolefin is not particularly limited. reaction to graft polymerize), and the like.

<Acid-modified polystyrene resin>
In the present invention, an acid-modified polystyrene resin can be preferably used as the acid-modified resin. The acid-modified polystyrene resin is not limited, but an aromatic vinyl compound alone or a copolymer mainly composed of block and/or random structure of an aromatic vinyl compound and a conjugated diene compound, and its hydrogenated product, It is preferably modified with a saturated carboxylic acid. Examples of aromatic vinyl compounds include, but are not limited to, styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, divinylbenzene, 1,1-diphenylstyrene, N,N-diethyl-p-aminoethyl. Styrene, vinyl toluene, p-tert-butyl styrene and the like can be mentioned. Examples of conjugated diene compounds include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene and the like. Specific examples of copolymers of these aromatic vinyl compounds and conjugated diene compounds include styrene-ethylene-butylene-styrene block copolymers (SEBS), styrene-ethylene-propylene-styrene block copolymers (SEPS), Styrene-ethylene-ethylene/propylene-styrene block copolymer (SEEPS) and the like are included.

<Acid-modified cycloolefin polymer>
In the present invention, it is also preferable to use an acid-modified cycloolefin polymer as the acid-modified resin. The acid-modified cycloolefin polymer is obtained by introducing a carboxy group into the cycloolefin polymer by acid modification, and the cycloolefin polymer is a homopolymer (COP) made from only one type of cycloolefin monomer, or one or more types. Any copolymer (COC) composed of cycloolefin monomers and comonomers can be used.

Examples of the cycloolefin monomer include bicyclics such as norbornene and norbornadiene, tricyclics such as dicyclopentadiene and dihydroxypentadiene, tetracyclics such as tetracyclododecene, and pentacyclics such as cyclopentadiene trimer. , Heptacyclics such as tetracyclopentadiene, or polycyclics thereof substituted with alkyl (methyl, ethyl, propyl, butyl, etc.), alkenyl (vinyl, etc.), alkylidene (ethylidene, etc.), aryl (phenyl, tolyl, naphthyl, etc.) substituted products. Among these, norbornene-based monomers selected from the group consisting of norbornene, tetracyclododecene, and alkyl-substituted products thereof are particularly preferred.

Moreover, the comonomer may be any monomer as long as it is copolymerizable with the above-mentioned cycloolefin monomer, and for example, an alkene monomer is preferable. Examples of alkene monomers include α-olefins such as ethylene, propylene, 1-butene and 1-hexene, and isobutene. Alkene monomers may be linear or branched.

It is preferable that 50% by mass or more of the monomer component constituting the acid-modified cycloolefin polymer is the cycloolefin monomer, and more preferably 60% by mass or more is the cycloolefin monomer. When the cycloolefin monomer accounts for 50% by mass or more of the total monomer components, good solder heat resistance can be obtained. The polymerization method, polymerization conditions, and the like for polymerizing the monomer components are not particularly limited, and may be appropriately set in accordance with conventional methods.

<Compound A>
Compound A in the present invention is a compound having a terminal unsaturated hydrocarbon group and a 5% weight loss temperature of 260° C. or higher. By having a terminal unsaturated hydrocarbon group, it is possible to increase crosslink density and improve solder heat resistance by reaction with compound B described later. In addition, since hydroxyl groups that deteriorate the dielectric properties are not generated after the reaction, the adhesive can have excellent dielectric properties. Having two or more terminal unsaturated hydrocarbon groups in one molecule is preferable because the crosslink density can be further increased. Here, the terminal unsaturated hydrocarbon group refers to a group having a CH ₂ =C structure such as vinyl group, vinylidene group, allyl group, acrylic group, methacrylic group, styrene group, and the like.

The 5% weight loss temperature of compound A must be 260° C. or higher. It is preferably 270° C. or higher, more preferably 280° C. or higher, and still more preferably 290° C. or higher. When the 5% weight loss temperature is equal to or higher than the above value, soldering can be performed without causing poor appearance even at a temperature exceeding the melting point of solder.

Compound A preferably has an aromatic ring structure or an alicyclic structure as a structural unit. By having an aromatic ring structure or an alicyclic structure as a structural unit, solder heat resistance can be improved, and dielectric properties are also excellent. Among them, it is preferable to have an aromatic ring structure or an alicyclic structure as the skeleton of compound A, and polyphenylene ether or phenol resin is preferable. Specific examples of polyphenylene ethers having terminal unsaturated hydrocarbon groups include SA-9000 from SABIC and OPE-2St from Mitsubishi Gas Chemical. As the phenolic resin having a terminal unsaturated hydrocarbon group, Resitop FTC-809AE manufactured by Gun Ei Chemical Industry Co., Ltd. is exemplified.

The number average molecular weight of compound A is preferably 500 or more, more preferably 1000 or more. Also, it is preferably 100,000 or less, more preferably 10,000 or less. Within the above range, the solubility in a solvent is good, and a uniform adhesive coating film can be formed.

The content of the compound A in the adhesive composition of the present invention is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and still more preferably 10 parts by mass or more with respect to 100 parts by mass of the acid-modified resin. is. Also, it is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and even more preferably 50 parts by mass or less. Within the above range, both excellent adhesiveness and soldering heat resistance can be achieved.

<Compound B>
Compound B in the present invention is a compound having an epoxy group and a terminal unsaturated hydrocarbon group. By having an epoxy group, it can be reacted with an acid-modified resin or polycarbodiimide described later, and by having a terminal unsaturated hydrocarbon group, it can be reacted with compound A, so that the crosslink density is increased between these compounds. By increasing it, excellent solder heat resistance can be achieved. Here, the terminal unsaturated hydrocarbon group refers to a group having a CH ₂ =C structure such as vinyl group, vinylidene group, allyl group, acrylic group, methacrylic group, styrene group, and the like.

Compound B preferably has a ring structure. When the compound B has a ring structure, the heat resistance can be improved and the dielectric properties are also excellent. The ring structure of compound B is preferably an aromatic ring structure or an isocyanuric ring structure from the viewpoint of heat resistance. Specific examples of such compound B include diallyl monoglycidyl isocyanurate and diglycidyl monoallyl isocyanurate. By using these, the crosslink density can be increased and the solder heat resistance can be improved.

Compound B preferably has a molecular weight of 500 or less. It is more preferably 400 or less. When the molecular weight is equal to or less than the above value, the solubility in solvents and the reactivity with compound A, acid-modified resin, and polycarbodiimide are improved, the crosslink density is increased, and solder heat resistance can be improved.

The content of compound B in the adhesive composition of the present invention is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and still more preferably 100 parts by mass of the acid-modified resin. It is 1 part by mass or more. Also, it is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less. Within the above range, both excellent adhesiveness and soldering heat resistance can be achieved. Moreover, the content of the compound B is preferably 1 equivalent or more of the terminal unsaturated hydrocarbon group with respect to the terminal unsaturated hydrocarbon group of the compound A. When the amount is 1 equivalent or more, the crosslink density can be increased and excellent solder heat resistance can be exhibited.

<Adhesive composition>
The adhesive composition of the present invention is an adhesive composition comprising an acid-modified resin, compound A and compound B. Here, compound A and compound B are the following compounds, respectively.
Compound A: a compound having a terminal unsaturated hydrocarbon group and a 5% weight loss temperature of 260°C or higher Compound B: a compound having an epoxy group and a terminal unsaturated hydrocarbon group Terminals of compound A and compound B Since the unsaturated hydrocarbon groups react with each other to cure without generating hydroxyl groups that deteriorate the dielectric properties, both excellent solder heat resistance and dielectric properties can be achieved.

The adhesive composition of the present invention preferably has a dielectric constant (εc) of 2.7 or less at a frequency of 10 GHz. It is more preferably 2.6 or less, still more preferably 2.3 or less. Although the lower limit is not particularly limited, it is practically 2.0. Also, the dielectric constant (εc) in the entire frequency range of 1 GHz to 60 GHz is preferably 2.7 or less, more preferably 2.6 or less, and even more preferably 2.3 or less.

The adhesive composition of the present invention preferably has a dielectric loss tangent (tan δ) of 0.003 or less at a frequency of 10 GHz. It is more preferably 0.0025 or less, and still more preferably 0.002 or less. Although the lower limit is not particularly limited, it is practically 0.0001 or more. Further, the dielectric loss tangent (tan δ) in the entire frequency range of 1 GHz to 60 GHz is preferably 0.003 or less, more preferably 0.0025 or less, and even more preferably 0.002 or less.

<Radical generator>
The adhesive composition of the present invention also preferably contains a radical generator. In the adhesive composition of the present invention, compound A and compound B can be reacted by heating, but the radicals generated by the radical generator cause the terminal unsaturated hydrocarbon groups of compound A and compound B to efficiently react with each other. By increasing the crosslink density, solder heat resistance and dielectric properties can be improved. Although the radical generator is not particularly limited, it is preferable to use an organic peroxide. Examples of organic peroxides include, but are not limited to, di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy- 2-ethylhexanoate, tert-butyl peroxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauroyl peroxide, 2,5-dimethyl-2,5-di(tertiarybutylperoxy)hexane and azonitriles such as azobisisobutyronitrile and azobisisopropionitrile.

The 1-minute half-life temperature of the radical generator used in the present invention is preferably 140° C. or higher. When the temperature is 140° C. or higher, the solvent of the adhesive composition varnish is volatilized to prevent the radical reaction from starting when the adhesive sheet is produced, and excellent adhesiveness can be exhibited.

The content of the radical generator in the adhesive composition of the present invention is preferably 0.1 part by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of compound A. Also, it is preferably 50 parts by mass or less, more preferably 20 parts by mass or less. By setting it within the above range, it is possible to obtain an optimum cross-linking density and achieve both adhesion and soldering heat resistance.

<Polycarbodiimide>
The adhesive composition of the invention can contain polycarbodiimide. Polycarbodiimide is not particularly limited as long as it has two or more carbodiimide bonds in the molecule. By using polycarbodiimide, the epoxy group of the acid-modified polystyrene elastomer or compound B reacts with the carbodiimide bond, and heat resistance and adhesiveness can be improved.

In the adhesive composition of the present invention, the content of polycarbodiimide is preferably 1 part by mass or more, more preferably 3 parts by mass or more, relative to 100 parts by mass of the acid-modified resin. By making it more than the said lower limit, a crosslink density can be raised and solder heat resistance becomes favorable. Also, it is preferably 20 parts by mass or less, more preferably 10 parts by mass or less. By adjusting the content to the above upper limit or less, excellent solder heat resistance and low dielectric properties can be exhibited. That is, within the above range, an adhesive composition having excellent solder heat resistance and low dielectric properties can be obtained.

<Epoxy resin>
The adhesive composition of the present invention can contain an epoxy resin different from compound B. The epoxy resin used in the present invention is not particularly limited as long as it has an epoxy group in the molecule, but preferably has two or more epoxy groups in the molecule. Specifically, but not limited to, biphenyl type epoxy resin, naphthalene type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, alicyclic epoxy resin, dicyclopentadiene type epoxy resin, at least one selected from the group consisting of tetraglycidyldiaminodiphenylmethane, triglycidyl para-aminophenol, tetraglycidylbisaminomethylcyclohexanone, N,N,N',N'-tetraglycidyl-m-xylenediamine, and epoxy-modified polybutadiene; can be used. Preferred are N,N,N',N'-tetraglycidyl-m-xylenediamine, biphenyl type epoxy resin, novolac type epoxy resin, dicyclopentadiene type epoxy resin and epoxy-modified polybutadiene. More preferred is N,N,N',N'-tetraglycidyl-m-xylenediamine, which can exhibit excellent adhesiveness.

In the adhesive composition of the present invention, the content of the epoxy resin is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, relative to 100 parts by mass of the acid-modified resin. More preferably, it is 1 part by mass or more. By making it more than the said lower limit, sufficient hardening effect can be acquired and the outstanding adhesiveness and soldering heat resistance can be expressed. Also, it is preferably 10 parts by mass or less, more preferably 5 parts by mass or less. When the content is equal to or less than the above upper limit, good pot life and low dielectric properties are obtained. That is, within the above range, it is possible to obtain an adhesive composition having excellent low dielectric properties in addition to adhesiveness, solder heat resistance and pot life.

The adhesive composition of the invention may further contain an organic solvent. The organic solvent used in the present invention is not particularly limited as long as it dissolves the acid-modified resin, compound A and compound B. Specifically, for example, aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as hexane, heptane, octane and decane; and alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane and ethylcyclohexane. Halogenated hydrocarbons such as hydrogen, trichlorethylene, dichlorethylene, chlorobenzene, chloroform, alcoholic solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, phenol, acetone, methyl isobutyl ketone, ketone solvents such as methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone and acetophenone; cellosolves such as methyl cellosolve and ethyl cellosolve; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate and butyl formate Ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso-butyl ether, triethylene glycol mono-n-butyl ether, tetraethylene glycol mono-n-butyl ether, etc. A glycol ether solvent or the like can be used, and one or more of these can be used in combination. In particular, methylcyclohexane and toluene are preferred from the standpoint of working environment and drying properties.

The organic solvent is preferably in the range of 100 to 1000 parts by mass with respect to 100 parts by mass of the acid-modified resin. By making it more than the said lower limit, liquid state and pot-life property become favorable. Moreover, setting the content to the above upper limit or less is advantageous in terms of manufacturing costs and transportation costs.

Moreover, the adhesive composition of the present invention may further contain other components as necessary. Specific examples of such components include flame retardants, tackifiers, fillers, and silane coupling agents.

<Flame retardant>
The adhesive composition of the present invention may optionally contain a flame retardant. Examples of flame retardants include bromine-based, phosphorus-based, nitrogen-based, and metal hydroxide compounds. Among them, phosphorus-based flame retardants are preferable, and known phosphorus-based flame retardants such as phosphate esters such as trimethyl phosphate, triphenyl phosphate and tricresyl phosphate, phosphates such as aluminum phosphinate, and phosphazenes can be used. . These may be used alone, or may be used in any combination of two or more. When containing a flame retardant, it is preferable to contain a flame retardant in the range of 1 to 200 parts by mass, more preferably 5 to 150 parts by mass, based on a total of 100 parts by mass of the acid-modified resin, compound A and compound B. Preferably, the range of 10 to 100 parts by weight is most preferred. By setting the content within the above range, it is possible to exhibit flame retardancy while maintaining adhesiveness, solder heat resistance, and electrical properties.

<Tackifier>
A tackifier may be added to the adhesive composition of the present invention, if necessary. Examples of tackifiers include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymer petroleum resins, styrene resins and hydrogenated petroleum resins. used in These may be used alone, or may be used in any combination of two or more. When a tackifier is contained, it is preferably contained in the range of 1 to 200 parts by mass, more preferably 5 to 150 parts by mass, with respect to the total 100 parts by mass of the acid-modified resin, compound A and compound B. A range of 10 to 100 parts by weight is most preferred. By setting the amount within the above range, the effect of the tackifier can be exhibited while maintaining adhesiveness, soldering heat resistance and electrical properties.

<Filler>
The adhesive composition of the present invention may optionally contain a filler. Examples of organic fillers include powders of heat-resistant resins such as polyimide, polyamideimide, fluororesin, and liquid crystal polyester. Examples of inorganic fillers include silica (SiO ₂ ), alumina (Al ₂ O ₃ ), titania (TiO ₂ ), tantalum oxide (Ta ₂ O ₅ ), zirconia (ZrO ₂ ), silicon nitride (Si ₃ N ₄ ), boron nitride (BN), calcium carbonate ( _CaCO3 ), calcium sulfate ( _CaSO4 ), zinc oxide (ZnO), magnesium titanate (MgO- _TiO2 ), barium sulfate ( _BaSO4 ), organic bentonite, clay , mica, aluminum hydroxide, magnesium hydroxide, etc. Among these, silica is preferable from the viewpoint of ease of dispersion and effect of improving heat resistance.

Hydrophobic silica and hydrophilic silica are generally known as silica, but here, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, etc. is used to impart moisture absorption resistance. is good. When silica is blended, the blending amount is preferably 0.05 to 30 parts by mass with respect to 100 parts by mass of the acid-modified resin, compound A and compound B in total. Further heat resistance can be expressed by making it more than the said lower limit. In addition, when the content is equal to or less than the above upper limit, poor dispersion of silica and excessive increase in solution viscosity are suppressed, and workability is improved.

<Silane coupling agent>
A silane coupling agent may be added to the adhesive composition of the present invention, if necessary. Addition of a silane coupling agent is very preferable because it improves adhesion to metals and heat resistance. Although the silane coupling agent is not particularly limited, examples thereof include those having an unsaturated group, those having an epoxy group, and those having an amino group. Among these, epoxy such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane is used from the viewpoint of heat resistance. A silane coupling agent having a group is more preferred. When the silane coupling agent is blended, the blending amount is preferably 0.5 to 20 parts by mass per 100 parts by mass of the acid-modified resin, compound A and compound B in total. Soldering heat resistance and adhesiveness can be improved by making it into the said range.

<Laminate>
The laminate of the present invention is obtained by laminating an adhesive composition on a base material (two-layer laminate of base material/adhesive layer), or further laminating a base material (base material/adhesive layer/ A three-layer laminate of substrates). Here, the adhesive layer refers to a layer of the adhesive composition after the adhesive composition of the present invention has been applied to a substrate and dried. The laminate of the present invention can be obtained by applying the adhesive composition of the present invention to various substrates, drying it, and further laminating another substrate in accordance with conventional methods.

<Base material>
In the present invention, the substrate is not particularly limited as long as the adhesive composition of the present invention can be applied and dried to form an adhesive layer. Examples include metal substrates such as plates and metal foils, papers, and the like.

Examples of resin substrates include polyester resins, polyamide resins, polyimide resins, polyamideimide resins, liquid crystal polymers, polyphenylene sulfides, syndiotactic polystyrene, polyolefin resins, fluorine resins, and the like. A film-like resin (hereinafter also referred to as a base film layer) is preferred.

Any conventionally known conductive material that can be used for circuit boards can be used as the metal substrate. Examples of materials include various metals such as SUS, copper, aluminum, iron, steel, zinc, and nickel, and their alloys, plated products, and metals treated with other metals such as zinc and chromium compounds. Metal foil is preferred, and copper foil is more preferred. Although the thickness of the metal foil is not particularly limited, it is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 10 μm or more. Also, it is preferably 50 μm or less, more preferably 30 μm or less, and still more preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit. Metal foils are usually provided in roll form. The form of the metal foil used in manufacturing the printed wiring board of the present invention is not particularly limited. When using a ribbon-shaped metal foil, the length is not particularly limited. Also, the width is not particularly limited, but it is preferably about 250 to 500 cm. The surface roughness of the substrate is not particularly limited, but is preferably 3 μm or less, more preferably 2 μm or less, and still more preferably 1.5 μm or less. Moreover, it is practically preferably 0.3 μm or more, more preferably 0.5 μm or more, and still more preferably 0.7 μm or more.

Examples of papers include woodfree paper, kraft paper, roll paper, glassine paper, and the like. Moreover, glass epoxy etc. can be illustrated as a composite material.

Based on adhesive strength and durability with the adhesive composition, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, fluororesin, A SUS steel plate, copper foil, aluminum foil, or glass epoxy is preferred.

<Adhesive sheet>
In the present invention, the adhesive sheet is obtained by laminating the laminate and the release substrate via an adhesive composition. Specific configuration modes include laminate/adhesive layer/release substrate, or release substrate/adhesive layer/laminate/adhesive layer/release substrate. By laminating the release base material, it functions as a protective layer for the base material. Moreover, by using a release base material, the release base material can be released from the adhesive sheet, and the adhesive layer can be transferred to another base material.

The adhesive sheet of the present invention can be obtained by applying the adhesive composition of the present invention to various laminates and drying in a conventional manner. In addition, when a release base material is applied to the adhesive layer after drying, it is possible to wind up the product without set-off to the base material, resulting in excellent workability and preservability due to the protection of the adhesive layer. excellent and easy to use. Further, if the adhesive layer itself is applied to a release base material and dried, and if necessary, another release base material is applied, the adhesive layer itself can be transferred to another base material.

<Release substrate>
The release substrate is not particularly limited, but for example, a coated layer of filler such as clay, polyethylene, polypropylene, etc. is applied to both sides of paper such as woodfree paper, kraft paper, roll paper, and glassine paper. and a silicone type, fluorine type or alkyd type release agent is applied on each coating layer. Other examples include various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer and propylene-α-olefin copolymer alone, and films such as polyethylene terephthalate coated with the release agent. For reasons such as the release force between the release base material and the adhesive layer, and the fact that silicone has an adverse effect on electrical properties, both sides of high-quality paper are filled with polypropylene and an alkyd-based release agent is used on top of it. Alternatively, it is preferable to use an alkyd release agent on polyethylene terephthalate.

In the present invention, the method of coating the substrate with the adhesive composition is not particularly limited, but examples thereof include a comma coater and a reverse roll coater. Alternatively, if necessary, an adhesive layer can be provided directly or by a transfer method on the rolled copper foil or polyimide film, which are the constituent materials of the printed wiring board. The thickness of the adhesive layer after drying may be changed as required, but is preferably in the range of 5 to 200 μm. Sufficient adhesive strength can be obtained by setting the thickness of the adhesive film to 5 μm or more. Further, by setting the thickness to 200 μm or less, it becomes easier to control the amount of residual solvent in the drying process, and blisters are less likely to occur during pressing in the manufacture of printed wiring boards. The drying conditions are not particularly limited, but the residual solvent rate after drying is preferably 1% by mass or less. When the amount is 1% by mass or less, foaming of the residual solvent is suppressed during pressing of the printed wiring board, and blisters are less likely to occur.

<Printed wiring board>
The printed wiring board in the present invention includes, as constituent elements, a laminate formed of a metal foil forming a conductive circuit and a resin base material, and examples thereof include flexible substrates, rigid substrates, package substrates, and the like. A printed wiring board is manufactured, for example, by a conventionally known method such as a subtractive method using a metal-clad laminate. If necessary, so-called flexible circuit boards (FPC), flat cables, tape automated bonding ( It is a general term for circuit boards for TAB).

The printed wiring board of the present invention can be of any laminate construction that can be employed as a printed wiring board. For example, it can be a printed wiring board composed of four layers: a base film layer, a metal foil layer, an adhesive layer, and a cover film layer. Further, for example, a printed wiring board can be made up of five layers: a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

Furthermore, if necessary, a configuration in which two or three or more of the above printed wiring boards are laminated can be employed.

The adhesive composition of the present invention can be suitably used for each adhesive layer of a printed wiring board. In particular, when the adhesive composition of the present invention is used as an adhesive, it has high adhesiveness not only to conventional polyimides, polyester films, and copper foils constituting printed wiring boards, but also to low-polarity resin substrates such as LCP. , solder reflow resistance can be obtained, and the adhesive layer itself has excellent low dielectric properties. Therefore, it is suitable as an adhesive composition used for coverlay films, laminates, resin-coated copper foils and bonding sheets.

In the printed wiring board of the present invention, any resin film conventionally used as a base material for printed wiring boards can be used as the base film. Examples of resins for the base film include polyester resins, polyamide resins, polyimide resins, polyamideimide resins, liquid crystal polymers, polyphenylene sulfides, syndiotactic polystyrene, polyolefin resins, fluorine resins, and the like. In particular, it has excellent adhesion even to low-polarity substrates such as liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene, and polyolefin resins.

<Cover film>
As the cover film, any insulating film conventionally known as an insulating film for printed wiring boards can be used. For example, films made from various polymers such as polyimide, polyester, polyphenylene sulfide, polyethersulfone, polyetheretherketone, aramid, polycarbonate, polyarylate, polyamideimide, liquid crystal polymer, syndiotactic polystyrene, and polyolefin resin are used. It is possible. Polyimide films or liquid crystal polymer films are more preferred.

The printed wiring board of the present invention can be manufactured using any conventionally known process except for using the materials for each layer described above.

In a preferred embodiment, a semi-finished product is produced by laminating an adhesive layer on a cover film layer (hereinafter referred to as a "cover film-side semi-finished product"). On the other hand, a semi-finished product in which a desired circuit pattern is formed by laminating a metal foil layer on a base film layer (hereinafter referred to as a "two-layer semi-finished product on the base film side"), or a semi-finished product in which an adhesive layer is laminated on a base film layer. , a semi-finished product having a desired circuit pattern formed by laminating a metal foil layer thereon (hereinafter referred to as "base film side 3-layer semi-finished product") (hereinafter referred to as "base film side 2-layer semi-finished product"). Together with the base film side three-layer semi-finished product, it is referred to as the “base film side semi-finished product”). By laminating the semi-finished product on the cover film side and the semi-finished product on the base film side thus obtained, a printed wiring board having four or five layers can be obtained.

The semi-finished product on the substrate film side includes, for example, (A) a step of applying a solution of a resin that will be the substrate film to the metal foil and initially drying the coating film, and (B) the metal foil obtained in (A) and It is obtained by a production method including a process of heat-treating and drying the laminate with the initially dried coating film (hereinafter referred to as "heat-treatment/solvent removal process").

A conventionally known method can be used to form a circuit in the metal foil layer. An additive method may be used, or a subtractive method may be used. A subtractive method is preferred.

The semi-finished product on the base film side thus obtained may be used as it is for lamination with the semi-finished product on the cover film side. may be used.

The semi-finished product on the cover film side is manufactured, for example, by applying an adhesive to the cover film. If desired, a cross-linking reaction in the applied adhesive can be performed. In a preferred embodiment, the adhesive layer is semi-cured.

The semi-finished product on the cover film side thus obtained may be used as it is for bonding to the semi-finished product on the base film side. may be used for

The base film-side semi-finished product and the cover film-side semi-finished product are each stored in the form of rolls, for example, and then laminated together to manufacture a printed wiring board. Any method can be used as the bonding method, and for example, the bonding can be performed using a press or a roll. Also, both can be bonded together while being heated by a method such as using a hot press or a hot roll device.

For example, in the case of a soft and windable reinforcing material such as a polyimide film, the reinforcing material-side semi-finished product is preferably manufactured by applying an adhesive to the reinforcing material. In addition, in the case of reinforcing plates such as metal plates such as SUS and aluminum, and glass fiber hardened plates with epoxy resin that cannot be rolled up, the adhesive applied in advance to the release base material can be transferred and applied. It is preferably manufactured. Also, if necessary, a cross-linking reaction in the applied adhesive can be carried out. In a preferred embodiment, the adhesive layer is semi-cured.

The semi-finished product on the reinforcing material side thus obtained may be used as it is for bonding to the back surface of the printed wiring board, or it may be used for bonding to the semi-finished product on the base film side after being stored after being bonded with a release film. You may

The base film-side semi-finished product, the cover film-side semi-finished product, and the reinforcing material-side semi-finished product are all the printed wiring board laminate of the present invention.

EXAMPLES The present invention will be specifically described below with reference to Examples. Incidentally, in the present examples and comparative examples, parts simply indicate parts by mass.

<Physical property evaluation method>
(acid value measurement)
The acid value (equivalent/10 ⁶ g) in the present invention was obtained by dissolving the acid-modified resin in toluene and titrating with a methanol solution of sodium methoxide using phenolphthalein as an indicator.

(Number average molecular weight (Mn))
The number average molecular weight in the present invention is determined by Shimadzu Corporation Gel Permeation Chromatography (hereinafter referred to as GPC, standard substance: polystyrene resin, mobile phase: tetrahydrofuran, column: Shodex KF-802 + KF-804L + KF-806L, column temperature: 30°C, flow rate: 1.0 ml/min, detector: RI detector).

(Measurement of melting point and heat of fusion)
The melting point and the heat of fusion in the present invention are measured using a differential scanning calorimeter (hereinafter referred to as DSC, Q-2000 manufactured by TA Instruments Japan) at a rate of 20 ° C. / min. It is a value measured from the top temperature and area of the melting peak when the temperature is raised and melted again.

(Measurement of 5% weight loss temperature)
It was measured using a differential thermal/thermogravimetric simultaneous measurement device (Shimadzu Corporation, DTG-60). A 5 mg sample placed in an aluminum pan was heated at a heating rate of 10 ° C./min in an air atmosphere, and the temperature when 5% weight was lost due to thermal decomposition was 5% weight loss temperature (unit: °C).

(Relative permittivity (ε _c ) and dielectric loss tangent (tan δ))
The dielectric constant (ε _c ) and dielectric loss tangent (tan δ) of the acid-modified resin were measured using a network analyzer (manufactured by Anritsu Corporation) by the cavity resonator perturbation method under conditions of a temperature of 23° C. and a frequency of 10 GHz.

Production examples of adhesive compositions serving as examples of the present invention and adhesive compositions serving as comparative examples are shown below.

Synthesis example of acid-modified polyolefin (c1) In a 1 L autoclave, 100 parts by mass of a propylene-butene copolymer (“Tafmer (registered trademark) XM7080” manufactured by Mitsui Chemicals, Inc.), 150 parts by mass of toluene, 19 parts by mass of maleic anhydride, di After adding 6 parts by mass of -tert-butyl peroxide and raising the temperature to 140°C, the mixture was further stirred for 3 hours. Thereafter, the obtained reaction solution was cooled and then poured into a container containing a large amount of methyl ethyl ketone to precipitate a resin. Thereafter, the liquid containing the resin was centrifuged to separate and purify the acid-modified propylene-butene copolymer graft-polymerized with maleic anhydride, the (poly)maleic anhydride and the low molecular weight substances. Then, by drying at 70° C. for 5 hours under reduced pressure, a maleic anhydride-modified propylene-butene copolymer (c1, acid value 338 equivalents/10 ⁶ g, number average molecular weight 25,000, Tm 80° C., ΔH 35 J/g ).

The following were used as the acid-modified polystyrene resin.
(c2): Tuftec M1911 (manufactured by Asahi Kasei Corporation), acid value 37 equivalents/10 ⁶ g, dielectric constant 2.3, dielectric loss tangent 0.0008
(c3): Tuftec M1913 (manufactured by Asahi Kasei Corporation), acid value 185 equivalents/10 ⁶ g, dielectric constant 2.3, dielectric loss tangent 0.0008
(c4): Tuftec M1943 (manufactured by Asahi Kasei Corporation), acid value 185 equivalents/10 ⁶ g, dielectric constant 2.3, dielectric loss tangent 0.0008

Synthesis example of acid-modified cycloolefin polymer (c5) In a 1 L autoclave, 100 parts by mass of a cycloolefin polymer (“ZEONEX (registered trademark) RS420” manufactured by Nippon Zeon Co., Ltd.), 150 parts by mass of toluene, 19 parts by mass of maleic anhydride, di- 6 parts by mass of tert-butyl peroxide was added, the temperature was raised to 140° C., and the mixture was further stirred for 3 hours. Thereafter, the obtained reaction solution was cooled and then poured into a container containing a large amount of methyl ethyl ketone to precipitate a resin. Thereafter, the liquid containing the resin was centrifuged to separate and purify the acid-modified cycloolefin polymer graft-polymerized with maleic anhydride, (poly)maleic anhydride, and low-molecular-weight substances. Then, it was dried at 70° C. under reduced pressure for 5 hours to obtain a maleic anhydride-modified cycloolefin polymer (c5, acid value 339 equivalents/10 ⁶ g, dielectric constant 2.0, dielectric loss tangent 0.0008).

As compound A, the following was used.
(a1): SA-9000 (manufactured by SABIC, polyphenylene ether having a vinyl group, number average molecular weight of 1700, 5% weight loss temperature of 439°C)
(a2): FTC809AE (manufactured by Gunei Chemical Industry Co., Ltd., phenolic resin having a vinyl group, number average molecular weight of 1400, 5% weight loss temperature of 332°C)
(a3): PEGDA (manufactured by Sigma-Aldrich, polyethylene glycol diacrylate, weight average molecular weight 700, 5% weight loss temperature 220°C)
(a4): SA-90 (manufactured by SABIC, polyphenylene ether having a hydroxyl group end (having no terminal unsaturated hydrocarbon group), number average molecular weight of 1700, 5% weight loss temperature of 430°C.)

As compound B, the following was used.
(b1): DA-MGIC (manufactured by Shikoku Kasei Co., Ltd., diallyl monoglycidyl isocyanurate)
(b2): MA-DGIC (manufactured by Shikoku Chemical Industry Co., Ltd., monoallyl diglycidyl isocyanurate)
(b3): diallyl isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd.)

Other than the above, the following were used.
Tetrad X: epoxy resin (manufactured by Mitsubishi Gas Chemical Company, glycidylamine type epoxy)
Perbutyl P: radical generator (manufactured by NOF Corporation, bis(1-t-butylperoxy-1-methylethyl)benzene, 1 minute half-life temperature 175° C.)

<Example 1>
The acid-modified polyolefin (c1) obtained in the above synthesis example was dissolved in methylcyclohexane to prepare a methylcyclohexane varnish having a solid content concentration of 20% by mass. To this methylcyclohexane varnish, compound A (a1), compound B (b1), and PERBUTYL P were blended in amounts of 20 parts, 5 parts, and 3 parts, respectively, relative to 100 parts of acid-modified polyolefin (c1). An agent composition (S1) was obtained.
The resulting adhesive composition (S1) was evaluated for dielectric constant, dielectric loss tangent, peel strength, solder heat resistance, and adhesive sheet flexibility. The results are listed in Table 1.

<Examples 2 to 9, Comparative Examples 1 to 5>
An adhesive composition was prepared in the same manner as in Example 1 except that the type and amount of the curing agent and the like were changed as shown in Tables 1 and 2, and each evaluation was performed. The results are listed in Table 1.

<Example 10>
Using an acid-modified polystyrene resin (c2) as an acid-modified resin, (a1) as a compound A, (b1) as a compound B, and 20 parts, 5 parts, and 3 parts of perbutyl P with respect to 100 parts of the acid-modified polystyrene resin (c2). and dissolved in toluene to a solid concentration of 30% by mass to obtain an adhesive composition (S10).
The resulting adhesive composition (S10) was evaluated for dielectric constant, dielectric loss tangent, peel strength, solder heat resistance and adhesive sheet flexibility. The results are listed in Table 1.

<Examples 11 to 21, Comparative Examples 6 to 9>
An adhesive composition was prepared and evaluated in the same manner as in Example 10, except that the types and blending amounts of each component of the adhesive composition were changed as shown in Tables 1 and 2. The results are listed in Tables 1 and 2.

<Evaluation of Adhesive Composition>
(Relative permittivity (ε _c ) and dielectric loss tangent (tan δ))
The adhesive composition was applied to a Teflon (registered trademark) sheet having a thickness of 100 μm so that the thickness after drying was 25 μm, and dried at 130° C. for 3 minutes. After curing by heat treatment at 180° C. for 3 hours, the Teflon (registered trademark) sheet was peeled off to obtain an adhesive resin sheet for testing. The test adhesive resin sheet thus obtained was cut into strips of 8 cm×3 mm to obtain test samples. The relative dielectric constant (ε _c ) and dielectric loss tangent (tan δ) were measured by a cavity resonator perturbation method using a network analyzer (manufactured by Anritsu Corporation) under conditions of a temperature of 23° C. and a frequency of 10 GHz.
<Evaluation Criteria for Relative Permittivity>
○: 2.4 or less ×: Exceeding 2.4 <Evaluation criteria for dielectric loss tangent>
◎: less than 0.0020 ○: 0.0020 or more and less than 0.0025 ×: 0.0025 or more

(Peel strength (adhesiveness))
The adhesive composition was applied to a 12.5 μm thick polyimide film (manufactured by Kaneka Corporation, Apical (registered trademark)) so as to have a thickness of 25 μm after drying, and dried at 130° C. for 3 minutes. The adhesive film (B stage product) thus obtained was laminated to a 18 μm thick rolled copper foil (manufactured by Nippon Steel Chemical & Materials Co., Ltd., Espanex series). Bonding was performed by pressing the rolled copper foil so that the glossy surface of the rolled copper foil was in contact with the adhesive layer, and pressing for 280 seconds under a pressure of 2 MPa at 170°C. Then, it was cured by heat treatment at 180° C. for 3 hours to obtain a sample for peel strength evaluation. The peel strength was measured under the conditions of 25° C., film pulling, tensile speed of 50 mm/min, and 90° peeling. This test shows the bond strength at room temperature.
<Evaluation Criteria>
○: 1.0 N / mm or more ×: less than 1.0 N / mm

(solder heat resistance)
A sample for evaluation was prepared by the same method as for measuring the peel strength, and a sample piece of 2.0 cm×2.0 cm was immersed in a solder bath melted at 288° C., and the presence or absence of change in appearance such as blistering was confirmed.
<Evaluation Criteria>
◎: no swelling for 60 seconds or more ○: swelling for 30 seconds or more and less than 60 seconds ×: swelling for less than 10 seconds

(Adhesive sheet flexibility)
The adhesive composition is applied to a Teflon (registered trademark) sheet having a thickness of 100 μm so that the thickness after drying becomes 25 μm, and dried at 130° C. for 3 minutes. Next, the state of the coating film was checked when the sheet was bent 180°.
<Evaluation Criteria>
○: No cracks ×: Cracks present

As is clear from Table 1, Examples 1 to 21 are excellent in pot life, dielectric properties, peel strength, solder heat resistance and adhesive sheet flexibility. On the other hand, in Comparative Examples 1 and 6, since the compound B did not have an epoxy group, the curing was insufficient and the solder heat resistance was insufficient. Comparative Examples 2 and 7 did not contain the compound B and contained an epoxy resin, so the dielectric properties as an adhesive composition were poor. In Comparative Examples 3 and 8, since Compound A did not have a terminal unsaturated hydrocarbon group, curing was insufficient and solder heat resistance was insufficient. Also, the dielectric loss tangent was high due to the influence of the terminal hydroxyl group. In Comparative Example 4, since the acid-modified resin was not included, the adhesive sheet was brittle, and the peel strength and solder heat resistance were insufficient. Moreover, since the coating film was fragile, the dielectric constant and dielectric loss tangent could not be measured. Comparative Examples 5 and 9 were inferior in solder heat resistance because the 5% weight loss temperature of compound A was low.

INDUSTRIAL APPLICABILITY The adhesive composition of the present invention is excellent in heat resistance and adhesive strength, has a low dielectric constant and a low dielectric loss tangent, and has good sheet flexibility. Therefore, it is useful as an adhesive or an adhesive sheet for printed wiring boards applied to printed boards (flexible boards, rigid boards, package boards) in a high frequency range.

Claims (8)

An adhesive composition comprising an acid-modified resin, compound A and compound B.
Compound A: A compound having a terminal unsaturated hydrocarbon group and having a 5% weight loss temperature of 260°C or higher Compound B: A compound having an epoxy group and a terminal unsaturated hydrocarbon group 2. The adhesive composition according to claim 1, wherein the acid-modified resin contains at least one resin selected from acid-modified polyolefins, acid-modified polystyrene resins and acid-modified cycloolefin polymers. 3. The adhesive composition according to claim 1, wherein said compound A is a compound having an aromatic ring structure or an alicyclic structure as a structural unit. 3. The adhesive composition according to claim 1 or 2, wherein said compound A is a polyphenylene ether or phenolic resin having a terminal unsaturated hydrocarbon group. The adhesive composition according to any one of claims 1 to 4, wherein said compound B is a compound having an isocyanuric ring. An adhesive sheet having an adhesive layer comprising the adhesive composition according to any one of claims 1 to 5. A laminate having an adhesive layer comprising the adhesive composition according to any one of claims 1 to 5. A printed wiring board comprising the laminate according to claim 7 as a component.