CN117500895A

CN117500895A - Adhesive composition, adhesive sheet, electromagnetic wave shielding material, laminate, and printed wiring board

Info

Publication number: CN117500895A
Application number: CN202280042697.1A
Authority: CN
Inventors: 园田辽; 入泽隼人; 川楠哲生
Original assignee: Dongyang Textile Mc Co ltd
Current assignee: Dongyang Textile Mc Co ltd
Priority date: 2021-07-09
Filing date: 2022-07-07
Publication date: 2024-02-02
Also published as: WO2023282318A1; JP7409568B2; JPWO2023282318A1; KR20240031943A; TW202309213A

Abstract

The present invention provides an adhesive composition which has high adhesion to not only conventional polyimide and liquid crystal polymer but also metal base materials, can obtain high solder heat resistance, and is excellent in low dielectric characteristics and laser processability. The present invention provides an adhesive composition comprising a modified polyolefin resin (a), a polyimide resin (b) and a curing agent (c), wherein the polyimide resin (b) has at least one selected from the group consisting of polyolefin polyol, dimer diol, dimer diamine and dimer acid as a constituent unit.

Description

Adhesive composition, adhesive sheet, electromagnetic wave shielding material, laminate, and printed wiring board

Technical Field

The present invention relates to an adhesive composition. More specifically, the present invention relates to an adhesive composition for bonding a resin substrate to a resin substrate or a metal substrate. In particular, the present invention relates to an adhesive composition for a flexible printed wiring board (hereinafter abbreviated as FPC), and an adhesive sheet, an electromagnetic wave shielding material, a laminate, and a printed wiring board each containing the same.

Background

Flexible printed wiring boards (FPCs) have excellent flexibility and can cope with the multifunction and miniaturization of Personal Computers (PCs), smartphones, and the like, and are therefore often used for mounting electronic circuit boards in narrow and complex interiors. In recent years, with the progress of miniaturization, weight reduction, higher density, and higher output of electronic devices, performance requirements for circuit boards (electronic circuit boards) are increasing due to these trends. In particular, with the increase in the speed of signal transmission in FPCs, the increase in the frequency of signals has been advanced. Accordingly, there is an increasing demand for low dielectric characteristics (low dielectric constant, low dielectric loss tangent) of FPCs in a high frequency region. In order to achieve such low dielectric characteristics, it has been proposed to reduce dielectric loss of a substrate or an adhesive of an FPC. As the adhesive, a combination of polyolefin and epoxy resin (patent document 1) and a combination of elastomer and epoxy resin (patent document 2) are being developed.

Prior art literature

Patent literature

Patent document 1: international publication WO2016/047289

Patent document 2: international publication No. WO2014/147903

Disclosure of Invention

Problems to be solved by the invention

However, in patent document 1, it is difficult to say that the solder used for the adhesive between the reinforcing plate and the interlayer is excellent in heat resistance. In patent document 2, the storage stability after blending, which is important at the time of use, is insufficient.

In addition, in recent years, due to miniaturization of FPCs, circuit boards have been increased in density, and in order to ensure circuit conduction, hole forming processes such as blind holes and through holes by laser processing have been performed. In order to establish a high-precision technique of laser processing, processing using UV laser light is performed, and hole forming processing is mainly performed at a wavelength of 355nm, but laser processability is not studied in the above-mentioned document.

That is, an object of the present invention is to provide an adhesive composition which has good adhesion to both various resin substrates such as polyimide and metal substrates, and is excellent in solder heat resistance, low dielectric characteristics, and laser processability.

Means for solving the problems

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

[1] An adhesive composition comprising a modified polyolefin resin (a), a polyimide resin (b) and a curing agent (c),

the polyimide resin (b) has at least one selected from the group consisting of polyolefin polyol, polyolefin polyamine, polyolefin polycarboxylic acid, dimer diol, dimer diamine, and dimer acid as a constituent unit.

[2] The adhesive composition according to the item [1], wherein the acid value of the modified polyolefin resin (a) is 5 to 30mgKOH/g.

[3] The adhesive composition according to the item [1] or [2], wherein the curing agent (c) contains at least one selected from the group consisting of epoxy resins, polyisocyanates and polycarbodiimides.

[4] The adhesive composition according to any one of the above [1] to [3], wherein 50 to 95 parts by mass of the modified polyolefin resin (a) is contained per 100 parts by mass of the total of the modified polyolefin resin (a) and the polyimide resin (b).

[5] The adhesive composition according to any one of [1] to [4], wherein the relative dielectric constant at 10GHz is less than 3.0.

[6] The adhesive composition according to any one of the above [1] to [5], wherein the content of the curing agent (c) is 0.5 to 60 parts by mass based on 100 parts by mass of the total of the modified polyolefin resin (a) and the polyimide resin (b).

[7] An adhesive sheet comprising a layer formed of the adhesive composition according to any one of [1] to [6 ].

[8] An electromagnetic wave shielding material comprising a layer formed of the adhesive composition according to any one of [1] to [6 ].

[9] A laminate comprising a layer formed of the adhesive composition according to any one of [1] to [6 ].

[10] A printed wiring board comprising the laminate according to [9] as a constituent element.

Effects of the invention

The adhesive composition of the present invention has good adhesion to both various resin substrates such as polyimide and metal substrates, and is excellent in solder heat resistance, low dielectric characteristics, and laser processability.

Detailed Description

< modified polyolefin resin (a) >)

The modified polyolefin resin (a) (hereinafter also simply referred to as component (a)) used in the present invention is not limited, but is preferably a modified polyolefin resin obtained by grafting at least one of an α, β -unsaturated carboxylic acid and an acid anhydride thereof onto a polyolefin resin. The polyolefin resin means: homopolymers of olefin monomers such as ethylene, propylene, butene, butadiene, and isoprene, copolymers with other monomers, and polymers having a hydrocarbon skeleton such as a hydride or a halide of the obtained polymer. That is, the modified polyolefin resin (a) is preferably a modified polyolefin resin obtained by grafting at least one of an α, β -unsaturated carboxylic acid and an acid anhydride thereof onto at least one of polyethylene, polypropylene and a propylene- α -olefin copolymer.

The propylene- α -olefin copolymer is a polymer obtained by copolymerizing propylene as a main component with an α -olefin. As the α -olefin, for example, one or more of ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate, and the like can be used. Among these alpha-olefins, ethylene and 1-butene are preferable. 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 of the α, β -unsaturated carboxylic acid and its anhydride include maleic acid, itaconic acid, citraconic acid and their anhydrides. Of these, anhydride is preferable, and maleic anhydride is more preferable. Specifically, the modified polyolefin resin (a) includes, for example, maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, and maleic anhydride-modified propylene-ethylene-butene copolymer, and one or a combination of two or more of these maleic anhydride-modified polyolefin resins may be used.

The lower limit of the acid value of the modified polyolefin resin (a) is preferably 5mgKOH/g or more, more preferably 6mgKOH/g or more, and still more preferably 7mgKOH/g or more, from the viewpoints of solder heat resistance and adhesion to the resin substrate and the metal substrate. By setting the lower limit value or more, the reactivity with the curing agent (c) becomes good, and excellent adhesive strength can be exhibited. In addition, the crosslink density is high, and the solder heat resistance becomes good. The upper limit is preferably 30mgKOH/g or less, more preferably 28mgKOH/g or less, and still more preferably 25mgKOH/g or less. By setting the upper limit value or less, the adhesion becomes good. In addition, the viscosity and stability of the solvent become good, and excellent pot life can be exhibited. And, the manufacturing efficiency is also improved.

The number average molecular weight (Mn) of the modified polyolefin resin (a) is preferably in the range of 10,000 ～ 50,000. More preferably 15,000 ～ 45,000, still more preferably 20,000 to 40000, and particularly preferably 22,000 ～ 38,000. When the lower limit value is not less than the above-mentioned lower limit value, the cohesive force is good, and excellent adhesion can be exhibited. Further, when the upper limit value is not more than the above-mentioned upper limit value, fluidity is excellent and operability is improved.

The modified polyolefin resin (a) is preferably crystalline. The crystallinity in the present invention means: a Differential Scanning Calorimeter (DSC) was used, and the temperature was raised from-100 ℃ to 250 ℃ at 20 ℃/min, and a clear melting peak was shown during this temperature rise.

The melting point (Tm) of the modified polyolefin resin (a) is preferably in the range of 50℃to 120 ℃. More preferably in the range of 60℃to 100℃and most preferably in the range of 70℃to 90 ℃. When the lower limit value is not less than the above, the cohesive force from the crystals is good, and excellent adhesion and solder heat resistance can be exhibited. Further, when the upper limit value is not more than the above-mentioned upper limit value, the solution stability and fluidity are excellent, and the workability in bonding is improved.

The heat of fusion (. DELTA.H) of the modified polyolefin resin (a) is preferably in the range of 5J/g to 60J/g. More preferably in the range of 10J/g to 50J/g, and most preferably in the range of 20J/g to 40J/g. When the lower limit value is not less than the above, the cohesive force from the crystals is good, and excellent adhesion and solder heat resistance can be exhibited. Further, when the upper limit value is not more than the above-mentioned upper limit value, the solution stability and fluidity are excellent, and the workability in bonding is improved.

The method for producing the modified polyolefin resin (a) is not particularly limited, and examples thereof include a radical grafting reaction (i.e., a reaction in which a radical species is generated for a polymer to be a main chain and an unsaturated carboxylic acid and an acid anhydride are graft polymerized with the radical species as a polymerization initiation point) and the like.

The radical initiator is not particularly limited, and an organic peroxide is preferably used. The organic peroxide is not particularly limited, and examples thereof include peroxides such as di-t-butyl peroxyphthalate, t-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butyl peroxybenzoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxypivalate, methyl ethyl ketone peroxide, di-t-butyl peroxide, lauroyl peroxide and the like; azonitriles such as azobisisobutyronitrile and azobisisopropionitrile.

< polyimide resin (b) >

The polyimide resin (b) (hereinafter also simply referred to as component (b)) used in the present invention can be obtained by reacting a polycarboxylic acid derivative having an acid anhydride group with a polyisocyanate compound or a polyamine compound. The polyimide resin (b) used in the present invention is a polyimide resin having at least one selected from the group consisting of polyolefin polyol, polyolefin polyamine, polyolefin polycarboxylic acid, dimer diol, dimer diamine, and dimer acid as a constituent unit. Here, the polyimide resin means a polymer having an imide bond, and also includes polyimide resins, polyurethane imide resins, polyester imide resins, polyamide imide resins, and the like.

The polyimide resin (b) used in the present invention has at least one selected from the group consisting of polyolefin polyol, polyolefin polyamine, polyolefin polycarboxylic acid, dimer diol, dimer diamine and dimer acid as a constituent unit, whereby the polyimide resin (b) can be made lower in dielectric property and, in addition, the compatibility with the modified polyolefin resin (a) can be improved. The content of the constituent unit in the polyimide resin (b) is preferably 30 mass% or more, more preferably 40 mass% or more, and still more preferably 50 mass% or more. Further, the content is preferably 95% by mass or less, more preferably 90% by mass or less, and still more preferably 85% by mass or less. By setting the lower limit value or more, sufficient low dielectric characteristics are ensured; by setting the upper limit value or less, the solder heat resistance and laser processability become good.

The lower limit of the acid value of the polyimide resin (b) used in the present invention is preferably 1mgKOH/g or more, more preferably 1.5mgKOH/g or more, and still more preferably 2mgKOH/g or more, from the viewpoints of solder heat resistance, adhesion to a resin substrate or a metal substrate, and low dielectric characteristics. When the lower limit value is not less than the above-mentioned lower limit value, the reactivity with the curing agent (c) becomes good, and excellent adhesive strength can be exhibited. In addition, the crosslink density is high, and the solder heat resistance becomes good. The upper limit is preferably 25mgKOH/g or less, more preferably 23mgKOH/g or less, and still more preferably 20mgKOH/g or less. By setting the upper limit value or less, the low dielectric characteristics are improved. In addition, the viscosity and stability of the solution become good, and excellent pot life can be exhibited. And, the manufacturing efficiency is also improved.

The lower limit of the logarithmic viscosity of the polyimide resin (b) used in the present invention is preferably 0.05dl/g or more, more preferably 0.06dl/g or more, and even more preferably 0.07dl/g or more, from the viewpoints of adhesion to a resin substrate or a metal substrate and compatibility. By setting the lower limit value or more, the adhesion becomes good. The upper limit is preferably 0.40dl/g or less, more preferably 0.38dl/g or less, and still more preferably 0.35dl/g or less. When the upper limit value is not more than the above, compatibility with the modified olefin resin is improved. In addition, the viscosity and stability of the solution become good, and excellent pot life can be exhibited. And, the manufacturing efficiency is also improved.

< polycarboxylic acid derivative having acid anhydride group >

The polycarboxylic acid derivative having an acid anhydride group constituting the polyimide resin (b) used in the present invention may be, for example, an aromatic polycarboxylic acid derivative, an aliphatic polycarboxylic acid derivative or an alicyclic polycarboxylic acid derivative. These may be used alone or in combination of two or more. Among them, aromatic polycarboxylic acid derivatives are preferable. The valence of the polycarboxylic acid derivative is not particularly limited. Preferably, 1 molecule has 1 or 2 acid anhydride groups, and the polycarboxylic acid derivative having an acid anhydride group may contain 1 or more carboxyl groups.

Examples of the aromatic polycarboxylic acid derivative include, but are not particularly limited to, alkylene glycol dianhydrotrimellitate such as trimellitic anhydride (TMA), 2-bis [4- (3, 4-dicarboxyphenoxy) phenyl ] propionic anhydride (BisDA), p-phenylene bistrimellitate dianhydride (TAHQ), 4' - (hexafluoroisopropylidene) diphthalic anhydride (6 FDA), 2-bis [4- (2, 3-dicarboxyphenoxy) phenyl ] propionic anhydride, pyromellitic dianhydride, ethylene glycol bisanhydrotrimellitate, propylene glycol bisanhydrotrimellitate, 1, 4-butanediol bisanhydrotrimellitate, hexanediol bisanhydrotrimellitate, polyethylene glycol bisanhydrotrimellitate, polypropylene glycol bisanhydrotrimellitate, and the like; 3,3' -4,4' -diphenyl ketone tetracarboxylic dianhydride, 3' -4,4' -biphenyl tetracarboxylic dianhydride, 1,2,5, 6-naphthalene tetracarboxylic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,5, 6-pyridine tetracarboxylic dianhydride, 3,4,9, 10-perylene tetracarboxylic dianhydride, 3', 4' -diphenyl sulfone tetracarboxylic dianhydride, m-terphenyl-3, 3',4,4' -tetracarboxylic dianhydride, 4' -oxydiphthalic anhydride, 1, 3-hexafluoro-2, 2-bis (2, 3-or 3, 4-dicarboxyphenyl) propane dianhydride 2, 2-bis (2, 3-or 3, 4-dicarboxyphenyl) propane dianhydride 2, 2-bis (2, 3-or 3, 4-di) carboxyphenyl) propane dianhydride.

The aliphatic polycarboxylic acid derivative or alicyclic polycarboxylic acid derivative is not particularly limited, and examples thereof include butane-1, 2,3, 4-tetracarboxylic dianhydride, pentane-1, 2,4, 5-tetracarboxylic dianhydride, cyclobutane-tetracarboxylic dianhydride, hexahydro-pyromellitic dianhydride, cyclohex-1-en-2, 3,5, 6-tetracarboxylic dianhydride, 3-ethylcyclohex-1-en-3- (1, 2), 5, 6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohexane-3- (1, 2), 5, 6-tetracarboxylic dianhydride, 1-methyl-3-ethylcyclohex-1-en-3- (1, 2), 5, 6-tetracarboxylic dianhydride, 1-ethylcyclohexane-1- (1, 2), 3, 4-tetracarboxylic dianhydride, 1-propylcyclohexane-1- (2, 3), 3, 4-tetracarboxylic dianhydride, 1, 3-dipropylcyclohexane-1- (2, 3), 3- (2, 3) -tetracarboxylic dianhydride, dicyclohexyl-3, 4,3',4' -tetracarboxylic dianhydride, bicyclo [2, 1] heptane-2, 3,5, 6-tetracarboxylic dianhydride, bicyclo [2, 2] octane-2, 3,5, 6-tetracarboxylic dianhydride, bicyclo [2, 2] oct-7-ene-2, 3,5, 6-tetracarboxylic dianhydride, hexahydrotrimellitic anhydride, and the like.

These polycarboxylic acid derivatives having an acid anhydride group may be used singly or in combination of two or more. Among them, trimellitic anhydride, 2-bis [4- (3, 4-dicarboxyphenoxy) phenyl ] propionic acid dianhydride, p-phenylene bistrimellitate dianhydride, 4' - (hexafluoroisopropylidene) diphthalic anhydride, pyromellitic anhydride, ethylene glycol bisdehydrated trimellitic anhydride, 3',4' -diphenyl ketone tetracarboxylic dianhydride, or 3,3', 4' -biphenyl tetracarboxylic dianhydride is more preferable.

The content of the polycarboxylic acid derivative having an acid anhydride group in the polyimide resin (b) is preferably 1 mass% or more, more preferably 2 mass% or more, and still more preferably 3 mass% or more. The content is preferably 30% by mass or less, more preferably 35% by mass or less, and still more preferably 30% by mass or less. When the content is within the above range, excellent adhesion, solder heat resistance, laser processability, and low dielectric characteristics can be exhibited.

< polyolefin polyol component >

The polyolefin polyol component constituting the polyimide resin (b) used in the present invention has an effect as a soft component of the polyimide resin (b). The polyolefin polyol is a polymer having a polyolefin skeleton with a plurality of hydroxyl groups. Specific examples of such polyolefin polyols include polyethylene butylene glycol (polyethylene butylene polyol), polybutadiene glycol (polybutadiene polyol), and hydrogenated polybutadiene glycol (hydrogenated polybutadiene polyol). The polyolefin polyol may be used alone or in combination of two or more. Commercially available polyethylene butenediol has a trade name "POLYTAIL" (manufactured by Mitsubishi chemical corporation). Further, as a commercial product of polybutadiene diol, there is a product of trade name "KRASOL" (manufactured by Cray Valley company) or the like. Further, as a commercial product of hydrogenated polybutadiene diol, there is a trade name "NISSO-PB" (manufactured by Nippon Caddy Co., ltd.), and the like.

< dimer diol component >

The dimer diol component constituting the polyimide resin (b) used in the present invention has a function as a softening component of the polyimide resin (b). The dimer diol is preferably the reduction reaction product derived from a polymeric fatty acid. The polymer fatty acid is also called dimer acid, and is a (dimer) obtained by polymerizing an unsaturated fatty acid having 18 carbon atoms (C18), such as oleic acid, linoleic acid, and linolenic acid, a drying oil fatty acid or a semi-drying oil fatty acid, and a lower monoalcohol ester of these fatty acids in the presence or absence of a catalyst. The dimer diol may contain a residual unsaturated bond in its molecule, a triol as an impurity, and the like.

Examples of the dimer diol component include "Pripol2033" (mixture having a double bond) manufactured by Croda Japan, and "Pripol 2030" (mixture having no double bond), and "SOVERMOL 650NS" and "SOVERMOL 908" manufactured by BASF JAPAN, which may be used alone or in combination of two or more.

< dimer acid component >

The dimer acid component is a polymeric fatty acid of the starting material of the dimer diol described above. The dimer acid may be used singly or in combination of two or more. Examples of commercial products of dimer acids include "Pripol1004", "Pripol1006", "Pripol1009", "Pripol1013", "Pripol1015", "Pripol1017", "Pripol1022", "Pripol1025" and "Pripol1040" manufactured by Croda Japan; "Empol1008", "Empol1012", "Empol1016", "Empol1026", "Empol1028", "Empol1043", "Empol1061", "Empol1062", manufactured by BASF JAPAN corporation, and the like.

< dimer diamine component >

Examples of the dimer diamine component include compounds obtained by converting the carboxyl group of the dimer acid into an amine group. Examples of the conversion method include a method of amidating a carboxylic acid, aminating the carboxylic acid by huffman rearrangement, and further distilling and purifying the carboxylic acid. Examples of commercial products of dimer diamine include "Priamine1071", "Priamine1073", "Priamine1074", "Priamine1075" manufactured by Croda Japan, and "Versamine551" manufactured by BASF JAPAN. The dimer diamine may be used singly or in combination of two or more kinds.

< polyisocyanate Compound >

The polyisocyanate compound constituting the polyimide resin (b) used in the present invention is not particularly limited, and examples thereof include an aromatic polyisocyanate compound, an aliphatic polyisocyanate compound, and a cycloaliphatic polyisocyanate compound. More preferably an aromatic diisocyanate compound. The aromatic polyisocyanate compound is not particularly limited, examples include diphenylmethane-2, 4 '-diisocyanate, 3,2' -or 3,3 '-or 4,2' -or 4,3 '-or 5,2' -or 5,3 '-or 6,2' -or 6,3 '-dimethyldiphenylmethane-2, 4' -diisocyanate, 3,2 '-or 3,3' -or 4,2 '-or 4,3' -or 5,2 '-or 5,3' -or 6,2 '-or 6,3' -diethyldiphenylmethane-2, 4 '-diisocyanate, 3,2' -or 3,3 '-or 4,2' -or 4,3 '-or 5,2' -or 5,3 '-or 6,2' -or 6,3 '-dimethoxydiphenylmethane-2, 4' -diisocyanate, diphenylmethane-4, 4 '-diisocyanate (MDI) diphenylmethane-3, 3' -diisocyanate, diphenylmethane-3, 4 '-diisocyanate, diphenyl ether-4, 4' -diisocyanate, benzophenone-4, 4 '-diisocyanate, diphenyl sulfone-4, 4' -diisocyanate, toluene-2, 4-diisocyanate (TDI), toluene-2, 6-diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, naphthalene-2, 6-diisocyanate, 4'- [2,2 bis (4-phenoxyphenyl) propane ] diisocyanate, 3' -or 2,2 '-dimethylbiphenyl-4, 4' -diisocyanate, 3,3' -or 2,2' -diethylbiphenyl-4, 4' -diisocyanate, 3' -dimethoxybiphenyl-4, 4' -diisocyanate, 3' -diethoxybiphenyl-4, 4' -diisocyanate, and the like. In view of solder heat resistance, adhesion, solubility, cost, etc., diphenylmethane-4, 4' -diisocyanate, toluene-2, 4-diisocyanate, m-xylene diisocyanate, 3' -or 2,2' -dimethylbiphenyl-4, 4' -diisocyanate are preferable, and diphenylmethane-4, 4' -diisocyanate and toluene-2, 4-diisocyanate are more preferable. Further, these may be used singly or in combination of two or more.

< polyamine Compound >

The polyamine compound constituting the polyimide resin (b) used in the present invention is not particularly limited, and examples thereof include a diamine compound and a polyamine compound. In relation to the diamine compound(s), examples thereof include 1, 4-diaminobenzene, 1, 3-diaminobenzene, 1, 2-diaminobenzene, 1, 5-diaminonaphthalene, 1, 8-diaminonaphthalene, 2, 3-diaminonaphthalene, 2, 6-diaminotoluene, 2, 4-diaminotoluene, 3, 4-diaminotoluene, 4 '-diaminodiphenylmethane, 3,4' -diaminodiphenylether, and aromatic diamines such as 4,4 '-diaminodiphenyl ether, 4' -diamino-1, 2-diphenylethane, 3 '-diaminodiphenylmethane, 3,4' -diaminodiphenylmethane, 4 '-diaminobenzophenone, 4' -diaminodiphenylsulfone, 3 '-diaminobenzophenone, and 3,3' -diaminodiphenylsulfone; aliphatic diamines such as ethylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, 1, 6-hexamethylenediamine, 1, 7-heptylenediamine, 1, 9-nonylenediamine, 1, 12-dodecylenediamine, and m-xylylenediamine; and alicyclic diamines such as isophorone diamine, norbornane diamine, 1, 2-cyclohexane diamine, 1, 3-cyclohexane diamine, 1, 4-cyclohexane diamine, 4' -diaminodicyclohexylmethane, and alicyclic diamines such as piperazine. The polyamine may be used singly or in combination of two or more.

The content of the isocyanate compound and the polyamine compound in the polyimide resin (b) is preferably 10 mass% or more, more preferably 13 mass%, and still more preferably 15 mass% or more. Further, it is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

The method for producing the polyimide resin (b) used in the present invention is not particularly limited, and a conventionally known method for producing a polyimide resin can be applied. Regarding the use ratio of the raw materials for the polymerization reaction of the polyimide resin (B), the ratio of the total (a) of the respective equivalents of the acid anhydride group, the carboxyl group and the hydroxyl group to the total (B) of the respective equivalents of the isocyanate group and the amino group is preferably (B)/(a) =0.7 to 1.3, more preferably 0.8 to 1.2. When the molecular weight of the polyimide resin (b) is not less than the lower limit, the coating film can be prevented from becoming brittle. Further, by setting the upper limit value or less, the viscosity of the polyimide resin (b) is suppressed, and the leveling property at the time of applying the adhesive solution is improved.

The polymerization reaction of the polyimide resin (b) used in the present invention is preferably carried out in the presence of one or more organic solvents, for example, in the isocyanate method, by heat condensation while removing carbon dioxide generated by the dissociation from the reaction system.

The polymerization solvent may be any solvent having low reactivity with isocyanate groups and amine groups, and is preferably a solvent containing no basic compound such as amine. Examples of such an organic solvent include toluene, xylene, ethylbenzene, nitrobenzene, cyclohexane, isophorone, diethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, dipropylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, methyl methoxypropionate, ethyl methoxypropionate, methyl ethoxypropionate, ethyl acetate, N-butyl acetate, isoamyl acetate, ethyl lactate, acetone, methyl ethyl ketone, cyclohexanone, N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, ++, chloroform, and methylene chloride. These may be used alone or in combination of two or more.

The polymerization solvent is preferably N, N-dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, γ -butyrolactone, or cyclohexanone from the viewpoint of good volatility, polymerizability, or solubility of the polymer during drying. More preferably N-methylpyrrolidone or cyclohexanone. In addition, these may also be used as diluents for the adhesive composition of the present invention.

The amount of the solvent to be used is preferably 0.8 to 5.0 times (mass ratio) the amount of the polyimide resin (b) to be produced, more preferably 1.0 to 3.0 times. When the amount is not less than the lower limit, the viscosity increase during synthesis is suppressed, and stirring is improved. In addition, by being equal to or less than the upper limit value, a decrease in reaction rate can be suppressed.

The reaction temperature is preferably 60 to 200℃and more preferably 100 to 180 ℃. By setting the reaction temperature to the above lower limit, the reaction time can be shortened. In addition, when the amount is equal to or less than the upper limit, decomposition of the monomer component can be suppressed, and gelation by the three-dimensional reaction can be suppressed. The reaction temperature is changed in multiple stages. The reaction time may be appropriately selected depending on the scale of the batch, the reaction conditions employed, and particularly the reaction concentration.

For promoting the reaction, amines such as triethylamine, lutidine, picoline, undecene, triethylenediamine (1, 4-diazabicyclo [2, 2] octane), DBU (1, 8-diazabicyclo [5,4,0] -7-undecene) and the like; the reaction is carried out in the presence of a catalyst such as an alkali metal compound, alkaline earth metal compound, e.g., lithium methoxide, sodium ethoxide, potassium butoxide, potassium fluoride, or sodium fluoride, or a metal or semi-metal compound, e.g., titanium, cobalt, tin, zinc, or aluminum. Among them, triethylamine and DBU are preferable in view of insulation.

< curing agent (c) >

The resin composition of the present invention contains a curing agent (c). By adding the curing agent (c) to the resin composition, the adhesion and solder heat resistance can be further improved. As the curing agent (c), a known curing agent can be used. Examples of the curing agent (c) include epoxy resins, polyisocyanates, polycarbodiimides, oxazoline crosslinkers, and aziridine crosslinkers. Epoxy resins, polyisocyanates, polycarbodiimides are preferred. These crosslinking agents may be used singly or in combination of two or more.

< epoxy resin >

The epoxy resin used in the present invention is not particularly limited as long as it has an epoxy group in a molecule, and an epoxy resin having 2 or more epoxy groups in a molecule is preferable. Specifically, there are no particular restrictions on the epoxy resin, and examples thereof include biphenyl type epoxy resins, naphthalene type epoxy resins, bisphenol a type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, alicyclic type epoxy resins, dicyclopentadiene type epoxy resins, tetraglycidyl diaminodiphenylmethane, triglycidyl para-aminophenol, tetraglycidyl bisaminomethyl cyclohexanone, N' -tetraglycidyl-m-xylylenediamine, and epoxy-modified polybutadiene, and these may be used singly or in combination of two or more. Preferably a biphenyl type epoxy resin, a novolac type epoxy resin, or a dicyclopentadiene type epoxy resin. More preferably a novolac type epoxy resin, a dicyclopentadiene type epoxy resin.

The epoxy equivalent of the epoxy resin is preferably 50g/eq or more, more preferably 70g/eq or more, and still more preferably 80g/eq or more. Further, the content is preferably 400g/eq or less, more preferably 350g/eq or less, and still more preferably 300g/eq or less. When the amount is within the above range, excellent solder heat resistance can be exhibited.

< polycarbodiimide >

The polycarbodiimide used in the present invention is not particularly limited as long as it has a carbodiimide group in the molecule. Preferably, the polycarbodiimide has 2 or more carbodiimide groups in the molecule.

The polycarbodiimide may be any one of an aromatic carbodiimide compound, an alicyclic carbodiimide compound and an aliphatic carbodiimide compound, and these may be used alone or in combination of two or more. Examples of the aromatic carbodiimide compound include poly-m-phenylene carbodiimide, poly-p-phenylene carbodiimide, polytoluene carbodiimide, poly (diisopropylphenylene carbodiimide), poly (methyldiisopropylphenylene carbodiimide), and poly (4, 4' -diphenylmethane carbodiimide). Examples of the alicyclic carbodiimide compound include poly-m-cyclohexylcarbodiimide, poly-p-cyclohexylcarbodiimide, poly (4, 4 '-dicyclohexylmethane carbodiimide), and poly (3, 3' -dicyclohexylmethane carbodiimide). The aliphatic carbodiimide compound may be any of linear or branched aliphatic carbodiimide compounds. The aliphatic carbodiimide compound is preferably a linear one, and specifically includes polymethylene carbodiimide, polyethylene carbodiimide, polypropylene carbodiimide, polybutylene carbodiimide, polypentamethylene carbodiimide, polyhexamethylene carbodiimide, and the like. These may be used singly or in combination of two or more. Among them, an aromatic carbodiimide compound or a cycloaliphatic carbodiimide compound is preferable.

Further, if polycarbodiimide and an epoxy resin are used in combination as a curing agent, an effect of further improving the heat resistance of the solder can be expected.

< polyisocyanate >

The polyisocyanate used in the present invention is preferably a polyfunctional isocyanate compound having 2 or more isocyanate groups in 1 molecule. In addition, compounds derived from polyfunctional isocyanate compounds may also be used.

The polyisocyanate may be any one of an aromatic isocyanate compound, a cycloaliphatic isocyanate compound, or an aliphatic isocyanate compound, and these may be used alone or in combination of two or more. Among them, an aliphatic isocyanate compound is preferable, and an aliphatic diisocyanate compound is more preferable. Examples of the aromatic isocyanate compound include 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 1, 3-xylene diisocyanate, 1, 4-naphthalene diisocyanate, 1, 5-naphthalene diisocyanate, 1, 8-naphthalene diisocyanate, 3 '-biphenyl diisocyanate, 4' -biphenyl diisocyanate, 3 '-dimethyl-4, 4' -biphenyl diisocyanate, diphenylmethane-3, 3 '-diisocyanate, diphenylmethane-4, 4' -diisocyanate, 3 '-dimethyldiphenylmethane-4, 4' -diisocyanate, and the like, and these may be used singly or in combination of two or more. Among them, 3 '-dimethyl-4, 4' -biphenyldiisocyanate is preferable. Examples of the alicyclic isocyanate compound include isophorone diisocyanate, norbornene diisocyanate, 1, 2-cyclohexane diisocyanate, 1, 3-cyclohexane diisocyanate, 1, 4-cyclohexane diisocyanate, dicyclohexylmethane-4, 4' -diisocyanate, and the like, and these may be used alone or in combination of two or more. The aliphatic isocyanate compound may be any of linear or branched aliphatic isocyanates. The aliphatic diisocyanate compound is preferably a linear one, and specifically, 1, 3-propane diisocyanate, 1, 4-tetramethylene diisocyanate, 1, 5-pentamethylene diisocyanate, 1, 6-hexamethylene diisocyanate, 1, 7-heptamethylene diisocyanate, 1, 8-octamethylene diisocyanate, 1, 9-nonamethylene diisocyanate, etc. may be used alone or in combination of two or more. Among them, 1, 6-hexamethylene diisocyanate is preferable.

The polyisocyanate may also be an isocyanurate, an adduct, a biuret, an uretdione or an allophanate of the isocyanate compound. In addition, blocked isocyanates in which the isocyanate groups are blocked can also be used as polyisocyanates. These compounds may be used alone or in combination of two or more. Among them, isocyanurate or biuret are preferable.

In the adhesive composition of the present invention, the content of the curing agent (c) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still more preferably 5 parts by mass or more, and particularly preferably 10 parts by mass or more, based on 100 parts by mass of the total of the modified polyolefin (a) and the polyimide resin (b). By setting the lower limit value or less, a sufficient curing effect can be obtained, and excellent adhesion and solder heat resistance can be exhibited. Further, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and still more preferably 40 parts by mass or less. By setting the upper limit value or less, the adhesive composition has good low dielectric characteristics. That is, when the content is within the above range, an adhesive composition having excellent low dielectric characteristics in addition to adhesion, solder heat resistance and pot life can be obtained.

< adhesive composition >

The adhesive composition of the present invention can exhibit excellent adhesion to low-polarity resin substrates such as Liquid Crystal Polymers (LCPs) and metal substrates, low dielectric characteristics, solder heat resistance and laser processability by containing 3 of the above-mentioned components (a) to (c). That is, the adhesive coating film (adhesive layer) obtained by applying the adhesive composition to a substrate and curing the adhesive composition can exhibit excellent low dielectric characteristics, solder heat resistance, and laser processability.

In the adhesive composition of the present invention, the content of the modified polyolefin resin (a) is preferably 50 parts by mass or more based on 100 parts by mass of the total of the modified polyolefin resin (a) and the polyimide resin (b). More preferably 60 parts by mass or more, and still more preferably 65 parts by mass or more. The amount is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, and still more preferably 85 parts by mass or less. By setting the content of the modified polyolefin resin (a) within the above-mentioned range, the adhesiveness, low dielectric characteristics, laser processability and compatibility are improved.

The adhesive composition of the present invention may further contain an organic solvent. The organic solvent that can be used in the present invention is not particularly limited as long as it dissolves or disperses the modified polyolefin (a), the polyimide resin (b) and the curing agent (c). Specifically, for example, aromatic hydrocarbons such as benzene, toluene, xylene, etc. can be used; aliphatic hydrocarbons such as hexane, heptane, octane, decane; alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane, ethylcyclohexane and the like; halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, chloroform, etc.; alcohol solvents such as methanol, ethanol, isopropanol, butanol, pentanol, hexanol, propylene glycol, and phenol; ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, acetophenone, and the like; cellosolves such as methyl cellosolve and ethyl cellosolve; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate; glycol ether solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol mono-isobutyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-isobutyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether may be used alone or in combination of two or more. In particular, methylcyclohexane and toluene are preferable from the viewpoint of work environment and drying property.

The organic solvent is preferably in the range of 100 to 1000 parts by mass, more preferably in the range of 200 to 900 parts by mass, and most preferably in the range of 300 to 800 parts by mass, based on 100 parts by mass of the total of the solids of the modified olefin (a), the polyimide resin (b), and the curing agent (c). By setting the lower limit value or more, the liquid state and the pot life become good. Further, setting the upper limit value or less is advantageous in terms of manufacturing cost and transportation cost.

The adhesive composition according to the invention preferably has a relative dielectric constant (. Epsilon.) at a frequency of 10GHz _c ) Is 3.0 or less. More preferably 2.6 or less, and still more preferably 2.3 or less. The lower limit is not particularly limited, but practically 2.0 or more. The relative dielectric constant (. Epsilon.) in the entire frequency range of 1GHz to 60GHz is preferably 3.0 or less, more preferably 2.6 or less, and still more preferably 2.3 or less.

The adhesive composition according to the present invention preferably has a dielectric loss tangent (tan delta) of 0.02 or less at a frequency of 10 GHz. More preferably 0.01 or less, still more preferably 0.008 or less. The lower limit is not particularly limited, but practically 0.0001. The dielectric loss tangent (tan δ) in the entire frequency range of 1GHz to 60GHz is preferably 0.02 or less, more preferably 0.01 or less, and still more preferably 0.008 or less.

In the present invention, the relative dielectric constant (. Epsilon.) _c ) And the dielectric loss tangent (tan delta) can be measured as follows. That is, the adhesive composition was applied to the release substrate so that the thickness after drying became 25. Mu.m, and dried at about 130℃for 3 minutes. Then, the mixture was cured by heat treatment at about 140℃for about 4 hours, and the cured adhesive composition layer was then formed(adhesive layer) is peeled from the release film. Relative permittivity (. Epsilon.) at a frequency of 10GHz of the adhesive composition layer after peeling _c ) The measurement was performed. Specifically, the relative dielectric constant (. Epsilon.) can be calculated from the measurement by the cavity perturbation method _c ) And dielectric loss tangent (tan delta).

The adhesive composition of the present invention may further contain other components as needed within a range that does not impair the effects of the present invention. Specific examples of such components include flame retardants, tackifiers, fillers, and silane coupling agents.

< flame retardant >

The adhesive composition of the present invention may contain a flame retardant if necessary within a range that does not impair the effects of the present invention. By containing the flame retardant, flame retardancy can be imparted to the adhesive composition. The flame retardant is not particularly limited as long as it exhibits flame retardancy, and is preferably insoluble in an organic solvent. The flame retardant is preferably a flame retardant filler, and examples thereof include inorganic flame retardant fillers and organic flame retardant fillers. Examples of the inorganic flame retardant filler include metal hydroxide compounds such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, and barium hydroxide; metal carbonates such as basic magnesium carbonate, zinc carbonate, magnesium-calcium carbonate (a mixture of magnesium carbonate and calcium carbonate), calcium carbonate, and barium carbonate; metal oxides such as magnesium oxide, molybdenum oxide, zirconium oxide, tin oxide hydrate, and antimony oxide; boric acid metal compounds such as zinc borate, zinc metaborate, barium metaborate, etc.; inorganic metal compounds such as dolomite, hydrotalcite, borax, etc.; inorganic phosphorus compounds such as red phosphorus. Examples of the organic flame retardant filler include phosphorus flame retardants such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium phosphate amide, ammonium polyphosphate, urethane phosphate, urethane polyphosphate, aluminum triethyl phosphinate, aluminum trimethyl ethyl phosphinate, aluminum triphenyl phosphinate, zinc diethyl phosphinate, zinc dimethyl ethyl phosphinate, zinc diphenyl phosphinate, titanium diethyl phosphinate, titanium tetraethyl phosphinate, titanium dimethyl ethyl phosphinate, titanium tetramethyl ethyl phosphinate, titanium diphenyl phosphinate, and titanium tetraphenyl phosphinate; nitrogen flame retardants such as triazine compounds, cyanuric acid compounds, isocyanuric acid compounds, triazole compounds, tetrazole compounds, diazo compounds, and urea, such as melamine, melam, and melamine cyanurate; and silicon-based flame retardants such as organosilicon compounds and silane compounds. The flame retardant is preferably a metal hydroxide compound or a phosphorus compound, and among these, a phosphorus compound is more preferable, and for example, a phosphorus flame retardant filler such as aluminum phosphinate can be used. The phosphorus flame retardant includes an organic solvent-insoluble type (phosphorus flame retardant filler) and an organic solvent-soluble type (phosphorus flame retardant non-filler), but the organic solvent-insoluble type (phosphorus flame retardant filler) is preferable in the present invention. The flame retardant filler may be used alone or in combination of two or more. When the flame retardant is contained, the amount of the flame retardant is preferably in the range of 1 to 200 parts by mass, more preferably in the range of 5 to 150 parts by mass, and most preferably in the range of 10 to 100 parts by mass, based on 100 parts by mass of the total of the components (a) to (c). By setting the lower limit value or more, the effect of the thickener can be exhibited. Further, by setting the upper limit value or less, the adhesiveness, solder heat resistance, low dielectric characteristics, and the like are not lowered.

< tackifier >

The adhesive composition of the present invention may contain a tackifier as required within a range that does not impair the effects of the present invention. Examples of the tackifier include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymerized petroleum resins, styrene resins, hydrogenated petroleum resins, and the like, which are used for improving the adhesive strength. These may be used alone or in any combination of two or more. When the tackifier is contained, it is contained in a range of preferably 1 to 200 parts by mass, more preferably 5 to 150 parts by mass, and most preferably 10 to 100 parts by mass, based on 100 parts by mass of the total of the components (a) to (c). By setting the lower limit value or more, the effect of the thickener can be exhibited. Further, by setting the upper limit value or less, the adhesiveness, solder heat resistance, low dielectric characteristics, and the like are not lowered.

< Filler >

The adhesive composition of the present invention may contain a filler as needed within a range that does not impair the effects of the present invention. Here, the filler is different from the flame retardant filler described in the flame retardant, and examples thereof include silica. The addition of silica is very preferable because the heat resistance of the solder is improved. Among these, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, or the like is preferable for imparting moisture absorption resistance. In the case of adding silica, the amount of the silica is preferably 0.05 to 30 parts by mass based on 100 parts by mass of the total of the components (a) to (c). By setting the lower limit value or more, the effect of improving the heat resistance of the solder can be exhibited. Further, by setting the upper limit value or less, poor dispersion of silica does not occur, the solution viscosity is good, and the workability is good. In addition, the adhesiveness is not lowered.

< silane coupling agent >

The adhesive composition of the present invention may contain a silane coupling agent as needed within a range that does not impair the effects of the present invention. The silane coupling agent is highly preferable because the adhesion to metal and the heat resistance of solder are improved. The silane coupling agent is not particularly limited, and examples thereof include a silane coupling agent having an unsaturated group, a silane coupling agent having a glycidyl group, a silane coupling agent having an amino group, and the like. Among these, from the viewpoint of solder heat resistance, a silane coupling agent having a glycidyl group such as γ -glycidoxypropyl trimethoxysilane, β - (3, 4-epoxycyclohexyl) ethyl trimethoxysilane, or β - (3, 4-epoxycyclohexyl) ethyl triethoxysilane is more preferable. When the silane coupling agent is blended, the blending amount is preferably 0.5 to 20 parts by mass based on 100 parts by mass of the total of the components (a) to (c). When the amount is 0.5 parts by mass or more, excellent solder heat resistance is obtained. On the other hand, when the amount is 20 parts by mass or less, the solder heat resistance and the adhesion are improved.

< laminate >

The laminate of the present invention is a laminate in which an adhesive composition is laminated on a substrate (a 2-layer laminate of a substrate/an adhesive layer), or a laminate in which a substrate is further laminated (a 3-layer laminate of a substrate/an adhesive layer/a substrate). Here, the adhesive layer is a layer of the adhesive composition obtained by applying the adhesive composition of the present invention to a substrate and drying the same. The adhesive composition of the present invention can be applied to various substrates according to a conventional method and dried, and further laminated with other substrates, to thereby obtain a laminate of the present invention.

< substrate >

In the present invention, the substrate is not particularly limited as long as it is a substrate that can be coated with the adhesive composition of the present invention and dried to form an adhesive layer, and examples thereof include resin substrates such as film-like resins, metal substrates such as metal plates and metal foils, papers, and the like.

Examples of the resin base material include polyester resins, polyamide resins, polyimide resins, polyamideimide resins, liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resins, and fluorine resins. Preferably, the resin is in the form of a film (hereinafter also referred to as a base film layer).

As the metal base material, any conventionally known conductive material that can be used for a circuit board can be used. As the material, various metals such as SUS, copper, aluminum, iron, steel, zinc, nickel, and the like, and alloys of the respective metals, plated products, metals treated with other metals such as zinc or chromium compounds, and the like can be exemplified. Preferably a metal foil, more preferably a copper foil. The thickness of the metal foil is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and further preferably 10 μm or more. Further, it is preferably 50 μm or less, more preferably 30 μm or less, and still more preferably 20 μm or less. When the thickness is too small, it may be difficult to obtain sufficient electrical performance of the circuit, and when the thickness is too large, processing efficiency and the like at the time of circuit fabrication may be reduced. The metal foil is usually provided in a roll-like form. The form of the metal foil used in manufacturing the printed wiring board of the present invention is not particularly limited. When a metal foil in a tape-like form is used, the length thereof is not particularly limited. The width is not particularly limited, and is preferably about 250 to 500 cm.

As the paper, woodfree (woodfree) paper, kraft paper, roll paper, cellophane, and the like can be exemplified. Further, as the composite material, glass epoxy resin or the like can be exemplified.

The base material is preferably a polyester resin, a polyamide resin, a polyimide resin, a polyamideimide resin, a liquid crystal polymer, a polyphenylene sulfide, a syndiotactic polystyrene, a polyolefin resin, a fluorine resin, a SUS steel plate, a copper foil, an aluminum foil, or a glass epoxy resin in terms of adhesion to the adhesive composition and durability.

< adhesive sheet >

In the present invention, the adhesive sheet is an adhesive sheet obtained by laminating the laminate and the release substrate via an adhesive composition. Specific embodiments include a laminate, an adhesive layer, a release substrate, an adhesive layer, a laminate, an adhesive layer, and a release substrate. The release substrate is laminated to function as a protective layer for the substrate. In addition, by using the 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 according to a conventional method and drying. In addition, when the release substrate is attached to the adhesive layer after drying, the release substrate can be wound up without back printing on the substrate, and the adhesive layer is protected, so that the release substrate is excellent in storage property and easy to use. After the release base material is coated and dried, if necessary, another release base material may be attached, and the adhesive layer itself may be transferred to another base material.

< release substrate >

The release substrate is not particularly limited, and examples thereof include substrates in which a pore-filling agent coating layer such as clay, polyethylene, polypropylene or the like is provided on both sides of paper such as a paper of a woodboard, kraft paper, roll paper, or cellophane, and an organosilicon-based, fluorine-based, or alkyd-based release agent is further coated on each of the coating layers. Further, various olefin films such as polyethylene alone, polypropylene, ethylene- α -olefin copolymer, and propylene- α -olefin copolymer, and a substrate obtained by coating the above release agent on a film such as polyethylene terephthalate can be mentioned. For reasons such as the release force between the release substrate and the adhesive layer and the adverse effect of the silicone on the low dielectric characteristics, a substrate obtained by using an alkyd-based release agent after polypropylene pore-filling treatment on both sides of the ballast paper or a substrate obtained by using an alkyd-based release agent on polyethylene terephthalate is preferable.

The method of applying the adhesive composition to the substrate according to the present invention is not particularly limited, and examples thereof include comma coaters, reverse roll coaters, and the like. Alternatively, an adhesive layer may be provided directly or by a transfer method on a rolled copper foil or polyimide film as a constituent material of a printed wiring board, if necessary. The thickness of the adhesive layer after drying may be appropriately changed as needed, but is preferably in the range of 5 to 200. Mu.m. When the thickness of the adhesive film is less than 5. Mu.m, the adhesive strength is insufficient. When the particle size is 200 μm or more, there is a problem that drying is insufficient, a large amount of residual solvent remains, and foaming occurs during pressing in the production of a printed wiring board. The drying conditions are not particularly limited, and the residual solvent ratio after drying is preferably 1 mass% or less. When the amount exceeds 1% by mass, there is a problem in that the residual solvent foams and foaming occurs during the press of the printed wiring board.

< printed wiring Board >

The term "printed wiring board" in the present invention means a product containing a laminate of a metal foil forming a conductor circuit and a resin base material as a constituent element. For example, a printed wiring board is manufactured by a conventionally known method such as a Subtractive process using a metal-clad laminate. As necessary, a so-called flexible circuit board (FPC), a flat cable, a circuit board for Tape Automated Bonding (TAB), or the like, which partially or entirely covers a conductor circuit formed of a metal foil, using a cover film, screen printing ink, or the like, is collectively referred to as a printed wiring board.

The printed wiring board of the present invention may have any laminated structure that can be used as a printed wiring board. For example, a printed wiring board may be formed of 4 layers including a base film layer, a metal foil layer, an adhesive layer, and a cover film layer. For example, a printed wiring board may be formed of 5 layers including a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

Further, if necessary, 2 or 3 or more printed wiring boards may be laminated.

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 adhesion to not only conventional polyimide, polyester film, copper foil constituting a printed wiring board but also a low-polarity resin base material such as LCP, and thus, solder heat resistance can be obtained and the adhesive layer itself has excellent low dielectric characteristics. Therefore, the adhesive composition is suitable as an adhesive composition for a coverlay film, a laminate, a resin-coated copper foil, and a bonding sheet.

In the printed wiring board of the present invention, any resin film conventionally used as a base material of a printed wiring board can be used as the base material film. Examples of the resin of the base film include polyester resins, polyamide resins, polyimide resins, polyamideimide resins, liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resins, and fluorine resins. Particularly, the adhesive composition is excellent in adhesion to low-polarity substrates such as liquid crystal polymers, polyphenylene sulfide, syndiotactic polystyrene and polyolefin resins.

< cover film >

As the cover film, any conventionally known insulating film can be used as the insulating film for a printed wiring board. For example, films made of various polymers such as polyimide, polyester, polyphenylene sulfide, polyethersulfone, polyetheretherketone, aromatic polyamide, polycarbonate, polyarylate, polyamideimide, liquid crystal polymer, syndiotactic polystyrene, and polyolefin resin can be used. More preferably a polyimide film or a liquid crystal polymer film.

The printed wiring board of the present invention can be manufactured by using any conventionally known process in addition to the materials of the above layers.

A preferred embodiment is to manufacture a semi-finished product (hereinafter referred to as "cover film side semi-finished product") in which an adhesive layer is laminated on a cover film layer. On the other hand, a semi-finished product (hereinafter referred to as "substrate film side 2 layer semi-finished product") in which a metal foil layer is laminated on a substrate film layer to form a desired circuit pattern, or a semi-finished product (hereinafter referred to as "substrate film side 3 layer semi-finished product") in which an adhesive layer is laminated on a substrate film layer to form a desired circuit pattern (hereinafter referred to as "substrate film side 2 layer semi-finished product and substrate film side 3 layer semi-finished product are collectively referred to as" substrate film side semi-finished product ") is manufactured. By bonding the thus obtained cover film-side semifinished product to a base film-side semifinished product, a 4-layer or 5-layer printed wiring board can be obtained.

The substrate film-side semifinished product can be obtained, for example, by a production method comprising the following steps (a) and (B): (A) A step of applying a resin solution to the metal foil as a base film and initially drying the coating film; and (c) a step of heat-treating/drying the laminate of the metal foil obtained in (B) and the initial dry coating film (hereinafter referred to as "heat-treating/desolvating step").

The circuitry in the metal foil layer can be formed using methods known in the art. An addition method or a subtraction method may be used. The subtractive method is preferred.

The obtained base material film-side semi-finished product may be used as it is for bonding to the cover film-side semi-finished product, or may be used for bonding to the cover film-side semi-finished product after bonding to a release film and storage.

The cover film-side semifinished product can be produced, for example, by applying an adhesive to a cover film. If necessary, a crosslinking reaction may be performed in the applied adhesive. In a preferred embodiment, the adhesive layer is semi-cured.

The obtained semi-finished product on the cover film side may be used as it is for bonding to the semi-finished product on the base film side, or may be used for bonding to the semi-finished product on the base film side after bonding to a release film and storage.

The base film-side semifinished product and the cover film-side semifinished product may be stored in a roll form, for example, and then bonded to each other to produce a printed wiring board. As a bonding method, any method can be used, and for example, bonding can be performed using a press, a roll, or the like. In addition, the two may be bonded while heating by using a method such as a heated press or a heated roller device.

When the reinforcing material-side semifinished product is a flexible and reelable reinforcing material such as a polyimide film, it is preferable to apply an adhesive to the reinforcing material. In the case of a hard, non-reelable reinforcing plate such as a metal plate of SUS, aluminum, or the like, a plate obtained by curing glass fibers with an epoxy resin, for example, it is preferable to manufacture the reinforcing plate by transfer-coating an adhesive that is applied to a release substrate in advance. In addition, if necessary, a crosslinking reaction may be performed in the applied adhesive. In a preferred embodiment, the adhesive layer is semi-cured.

The obtained reinforcing material-side semi-finished product may be used as it is for bonding to the back surface of a printed wiring board, or may be used for bonding to a base material film-side semi-finished product after bonding to a release film and storage.

The base film-side semi-finished product, the cover film-side semi-finished product, and the reinforcing material-side semi-finished product are each a laminate for a printed wiring board in the present invention.

< electromagnetic wave shielding Material >

The electromagnetic wave shielding material of the present invention is an article having an adhesive layer formed using the adhesive composition of the present invention. In a preferred embodiment of the present invention, the adhesive layer contains an electromagnetic wave shielding material containing a conductive filler. Thus, malfunction of the electronic device due to noise of electromagnetic waves, leakage of confidential information due to hearing of communication electric waves, and the like can be prevented.

As a method for producing the electromagnetic wave shielding material of the present invention, for example, a method of bonding a conductive bonding sheet having an adhesive layer containing a conductive filler to a shielding material can be applied.

Examples

The present invention will be described in further detail with reference to examples. However, the present invention is not limited to the examples. The parts abbreviated in examples and comparative examples represent parts by mass.

(physical Property evaluation method)

(acid value (modified polyolefin resin))

The acid value (mgKOH/g) in the present invention is obtained by dissolving a resin sample in toluene, and titrating phenolphthalein with a methanol solution of sodium methoxide as an indicator.

(acid value (polyimide resin))

The acid value (mgKOH/g) in the present invention is obtained by dissolving a resin sample in N-methylpyrrolidone (NMP), and titrating phenolphthalein with a methanol solution of sodium methoxide as an indicator.

(number average molecular weight (Mn))

The number average molecular weight in the present invention is a value measured by a gel permeation chromatograph (hereinafter referred to as GPC, standard substance: polystyrene resin, mobile phase: tetrahydrofuran, column: shodex KF-802+KF-804L+KF-806L, column temperature: 30 ℃, flow rate: 1.0 ml/min, detector: RI detector) manufactured by Shimadzu corporation.

(determination of melting Point and Heat of fusion)

The melting point (Tm) and the heat of fusion (Δh) in the present invention are measured based on the top temperature and the area of a melting peak at the time of melting again by heating and melting at a rate of 20 ℃/min and cooling the resin using a differential scanning calorimeter (hereinafter referred to as DSC, TA Instruments Japan system, Q-2000).

(logarithmic viscosity)

The polyimide resin (b) was dissolved in NMP so that the polymer concentration became 0.6 g/dl. The solution viscosity and the solvent viscosity of the solution were measured at 30℃using an Ubbelohde viscosity tube and calculated by the following formula.

Logarithmic viscosity (dl/g) = [ ln (V1/V2) ]/V3

V1: calculation based on the time for solvent (NMP) to pass through the capillary of the Ubbelohde viscosity tube

V2: calculation of the time for the passage of the Polymer solution through the capillary of the Ubbelohde tube

V3: polymer concentration (g/dl)

(1) Adhesive strength

The adhesive composition described later was applied to a Polyimide (PI) film (manufactured by KANEKA, apical (registered trademark)) having a thickness of 12.5 μm or an LCP film (manufactured by KURARAY corporation, vecstar (registered trademark)) having a thickness of 25 μm so that the thickness component after drying was 25 μm, and dried at 130 ℃ for 3 minutes. The adhesive film (B-stage product) thus obtained was bonded to a rolled copper foil (BHY series, JX Metal Co., ltd.) having a thickness of 18. Mu.m. Bonding means that the glossy surface of the rolled copper foil is contacted with the adhesive layer at 160℃at 40kgf/cm ² Is pressed for 30 seconds under pressure to bond. Then, the resultant was cured by heat treatment at 160℃for 1 hour to obtain a sample for peel strength evaluation. The peel strength was measured by stretching the film at 25℃and performing a 90℃peel test at a stretching speed of 50 mm/min. This test shows the adhesive strength at room temperature.

< evaluation criterion >

And (3) the following materials: 1.0N/mm or more

O: 0.8N/mm or more and less than 1.0N/mm

Delta: 0.5N/mm or more and less than 0.8N/mm

X: less than 0.5N/mm

(2) Solder heat resistance

A sample was prepared in the same manner as in (1) above, and a 2.0 cm. Times.2.0 cm piece of the sample was subjected to aging treatment at 23℃for 2 days, and was floated in a molten solder bath at 280℃for 10 seconds, to confirm whether or not there was any change in appearance such as swelling.

< rating benchmark >

And (3) the following materials: no expansion

O: with a part expanding

Delta: has more expansion

X: has the advantages of swelling and color change

(3) Low dielectric characteristics (relative dielectric constant (. Epsilon.) _c ) Dielectric loss tangent (tan delta)

The adhesive composition described later was applied to a Teflon (registered trademark) sheet having a thickness of 100 μm so that the thickness after drying and curing became 25. Mu.m, and dried at 130℃for 3 minutes. Then, the process is carried out,the cured product was subjected to heat treatment at 160℃for 1 hour to obtain an adhesive resin sheet for test. The obtained adhesive resin sheet for test was cut into short strips of 8cm×3mm to obtain a sample for test. With respect to the relative dielectric constant (. Epsilon.) _c ) And dielectric loss tangent (tan. Delta.) were measured by a cavity perturbation method using a network analyzer (manufactured by Ind. Co., ltd.) at a temperature of 23℃and a frequency of 10 GHz. The relative permittivity and dielectric loss tangent obtained were evaluated as follows.

< evaluation criterion of relative permittivity >

And (3) the following materials: 2.3 or less

O: greater than 2.3 and less than 2.6

Delta: greater than 2.6 and less than 3.0

X: greater than 3.0

< evaluation criterion of dielectric loss tangent >

And (3) the following materials: 0.008 or less

O: greater than 0.008 and less than 0.01

Delta: more than 0.01 and less than 0.02

X: greater than 0.02

(4) Absorbance at 355nm

The adhesive composition described later was applied to a Teflon (registered trademark) sheet having a thickness of 100 μm so that the thickness after drying and curing became 25. Mu.m, and dried at 130℃for 3 minutes. Then, the cured product was heat-treated at 140℃for 4 hours to obtain an adhesive resin sheet for test. Using the obtained adhesive resin sheet, absorbance at 355nm was measured by an ultraviolet-visible spectrophotometer V-650 (manufactured by Japanese Spectrophotometer Co., ltd.).

< evaluation criterion >

O: abs is 0.3 or more.

Delta: abs is 0.2 or more and less than 0.3.

X: abs is less than 0.2.

(5) Compatibility of

The adhesive composition described later was applied to a polypropylene film having a thickness of 50. Mu.m, and dried at 130℃for 3 minutes so that the thickness after drying and curing became 25. Mu.m. The appearance of the obtained adhesive resin sheet was visually confirmed.

< evaluation criterion >

O: no foreign matter and unevenness.

Delta: a small unevenness was seen.

X: has foreign matter, unevenness, or is not coated.

Production example of modified polyolefin resin (a)

Production example 1

To a 1L autoclave, 100 parts by mass of a propylene-butene copolymer (Tafmer (registered trademark) XM7080, sanjing chemical Co., ltd.), 150 parts by mass of toluene, 19 parts by mass of maleic anhydride, and 6 parts by mass of di-t-butyl peroxide were added, and the mixture was heated to 140℃with stirring, and then stirred for 3 hours. Then, the obtained reaction solution was cooled and poured into a container containing a large amount of methyl ethyl ketone to precipitate a resin. Then, the acid-modified propylene-butene copolymer obtained by graft polymerization of maleic anhydride, and (poly) maleic anhydride and a low molecular weight substance are separated and purified by centrifugal separation of a liquid containing the resin. Then, the resultant was dried under reduced pressure at 70℃for 5 hours to obtain a maleic anhydride-modified propylene-butene copolymer (a-1, acid value 19mgKOH/g, number average molecular weight 25,000, tm80 ℃, deltaH 35J/g) as a modified polyolefin resin.

Production example 2

A maleic anhydride-modified propylene-butene copolymer (a-2, acid value 14mgKOH/g, number average molecular weight 30,000, tm78 ℃ C.,. DELTA.H 25J/g) was obtained as a modified polyolefin resin in the same manner as in production example 1 except that the amount of maleic anhydride added was changed to 14 parts by mass.

Production example 3

A maleic anhydride-modified propylene-butene copolymer (a-3, acid value 11mgKOH/g, number average molecular weight 33,000, tm80 ℃, deltaH 25J/g) was obtained as a modified polyolefin resin in the same manner as in production example 1 except that the amount of maleic anhydride added was changed to 11 parts by mass.

Production example 4

A maleic anhydride-modified propylene-butene copolymer (a-4, acid value 7mgKOH/g, number average molecular weight 35,000, tm82 ℃ C.,. DELTA.H 25J/g) was obtained as a modified polyolefin resin in the same manner as in production example 1 except that the amount of maleic anhydride added was changed to 6 parts by mass.

(production example of polyimide resin (b))

Production example 5

17.3 parts by mass of trimellitic anhydride (manufactured by Polynt), 315.0 parts by mass of polybutadiene diol (manufactured by Nippon Cauda, trade name GI-1000, molecular weight 1500) and 75.9 parts by mass of 4,4' -diphenylmethane diisocyanate (MDI) (manufactured by Tosoh, trade name Milliconate MT) as isocyanate components were added to a flask, and dissolved in 611.1 parts by mass of cyclohexanone. Further, as a catalyst, 0.69 parts by mass of DBU was added. Then, the mixture was reacted under nitrogen flow at 130℃for 5 hours while stirring, and then cooled to room temperature, whereby a polyimide resin (b-1) solution having a nonvolatile content (solid content) of 40% by mass, an acid value of 4.6mgKOH/g and a logarithmic viscosity of 0.190dl/g was obtained.

Production example 6

17.3 parts by mass of trimellitic anhydride (manufactured by Polynt), 117.6 parts by mass of dimer diol (manufactured by Croda Japan, trade name Pripol2033, molecular weight 560), and 75.1 parts by mass of 4,4' -diphenylmethane diisocyanate (MDI) (manufactured by Tosoh, trade name Milliconate MT) as isocyanate components were added to a flask, and dissolved in 157.5 parts by mass of cyclohexanone and 157.5 parts by mass of N-methylpyrrolidone. Further, as a catalyst, 0.69 parts by mass of DBU was added. Then, the mixture was reacted under nitrogen flow at 130℃for 6 hours while stirring, and then cooled to room temperature, whereby a polyimide resin (b-2) solution having a nonvolatile content (solid content) of 40% by mass, an acid value of 6.7mgKOH/g and a logarithmic viscosity of 0.168dl/g was obtained.

Production example 7

210.00 parts by mass of 3,3'-4,4' -diphenyl ketone tetracarboxylic dianhydride (Evonik Japan, manufactured) and 1000.80 parts by mass of cyclohexanone as well as 201.60 parts by mass of methylcyclohexane were added, heated to 60 ℃, 341.67 parts by mass of dimer diamine (manufactured by Croda Japan, trade name Priamine1075, molecular weight 549) was then added dropwise, and then an imide reaction was carried out at 140℃for 10 hours, cooled to room temperature, thereby obtaining a polyimide resin (b-3) solution having a nonvolatile content (solid content) of 30% by mass, an acid value of 5.6mgKOH/g, and a logarithmic viscosity of 0.240 dl/g.

Production example 8

34.6 parts by mass of trimellitic anhydride (manufactured by Polynt), 235.2 parts by mass of dimer acid (manufactured by Croda Japan, trade name Pripol1009, molecular weight 566) and 145.7 parts by mass of 4,4' -diphenylmethane diisocyanate (MDI) (manufactured by Tosoh, trade name Milliconate MT) as isocyanate components were added to a flask, and dissolved in 623.1 parts by mass of N-methylpyrrolidone. Further, 1.37 parts by mass of DBU was added as a catalyst. Then, the mixture was reacted under nitrogen flow at 130℃for 5 hours while stirring, and then cooled to room temperature, whereby a polyimide resin (b-4) solution having a nonvolatile content (solid content) of 40% by mass, an acid value of 10.4mgKOH/g and a logarithmic viscosity of 0.318dl/g was obtained.

Production example 9

28.8 parts by mass of trimellitic anhydride (manufactured by Polynt), 225.0 parts by mass of polybutadiene glycol (manufactured by Nippon Cauda, trade name GI-1000), 75.1 parts by mass of 4,4' -diphenylmethane diisocyanate (MDI) (manufactured by Tosoh, trade name Milliconate MT) as an isocyanate component were added to a flask, and dissolved in 236.8 parts by mass of cyclohexanone and 236.8 parts by mass of N-methylpyrrolidone. Then, the mixture was reacted under nitrogen flow at 130℃for 5 hours while stirring, and then cooled to room temperature, whereby a polyimide resin (b-5) solution having a nonvolatile content (solid content) of 40% by mass, an acid value of 11.8mgKOH/g and a logarithmic viscosity of 0.139dl/g was obtained.

Production example 10

17.3 parts by mass of trimellitic anhydride (manufactured by Polynt), 420.0 parts by mass of polyester diol (manufactured by DIC, trade name ODX-2044, molecular weight 2000), and 72.8 parts by mass of 4,4' -diphenylmethane diisocyanate (MDI) (manufactured by Tosoh, trade name Milliconate MT) as isocyanate components were added to a flask, and dissolved in 765.2 parts by mass of cyclohexanone. Then, the mixture was reacted under nitrogen flow at 130℃for 8 hours while stirring, and then cooled to room temperature, whereby a polyimide resin (b-6) solution having a nonvolatile content (solid content) of 40% by mass, an acid value of 8.4mgKOH/g and a logarithmic viscosity of 0.250dl/g was obtained.

Production example 11

360.0 parts by mass of polybutadiene diol (trade name GI-1000, manufactured by Tosoh corporation), 8.89 parts by mass of 2, 2-bis (hydroxymethyl) butanoic acid, and 74.2 parts by mass of 4,4' -diphenylmethane diisocyanate (MDI) (trade name Milliconate MT, manufactured by Tosoh corporation) as isocyanate components were added to a flask, and dissolved in 664.8 parts by mass of cyclohexanone. Further, as a catalyst, 0.69 parts by mass of DBU was added. Then, the reaction was carried out under a nitrogen stream at 130℃for 5 hours with stirring, and then cooled to room temperature, whereby a polyurethane resin (b-7) solution having a nonvolatile content (solid content) of 40% by mass, an acid value of 5.6mgKOH/g and a logarithmic viscosity of 0.176dl/g was obtained.

The curing agent (c) used in table 1 is as follows.

(epoxy resin)

c-1: dicyclopentadiene type epoxy resin: HP-7200H (manufactured by DIC Co., ltd., epoxy equivalent 278 g/eq)

c-2: cresol novolac type epoxy resin: jER-152 (Mitsubishi chemical system, epoxy equivalent 177 g/eq)

c-3: glycidylamine type epoxy resin: jER-630 (Mitsubishi chemical system, epoxy equivalent 98 g/eq)

(polyisocyanates)

c-4: isocyanurate body of hexamethylene diisocyanate: SUMIDUR (registered trademark) N-3300 (manufactured by Bayer Co., ltd.)

(polycarbodiimide)

c-5: carbodiimide resin: v-09GB (carbodiimide equivalent 216g/eq manufactured by Niqing textile chemical Co., ltd.)

c-6: carbodiimide resin: v-03 (carbodiimide equivalent 209g/eq, manufactured by Niqing textile chemical Co., ltd.)

Example 1 ]

The modified polyolefin resin (a-1) was dissolved in an organic solvent (methylcyclohexane/toluene=80/20 (volume ratio)) to prepare a solution having a solid content concentration of 20 mass%. The curing agent (c-1) (epoxy resin, HP-7200H) was dissolved in an organic solvent (methyl ethyl ketone) to prepare a solution having a solid content concentration of 70% by mass. The solutions were blended so that the modified polyolefin resin (a-1) became 80 parts by mass, the polyimide resin (b-1) became 20 parts by mass, and the curing agent (c-1) became 10 parts by mass, to obtain an adhesive composition. The results of evaluating the adhesive strength, solder heat resistance, low dielectric characteristics, absorbance at 355nm and compatibility of the obtained adhesive composition are shown in Table 1.

< examples 2 to 23, comparative examples 1 to 5>

Examples 2 to 21 and comparative examples 1 to 5 were carried out in the same manner as in example 1 except that the blending amounts (solid parts) of the modified polyolefin resin (a), the polyimide resin (b) and the curing agent (c) were changed as shown in table 1. The results of evaluation of the adhesive strength, solder heat resistance, low dielectric characteristics, absorbance at 355nm, and compatibility are shown in table 1.

TABLE 1

As is clear from table 1, examples 1 to 23 show that the adhesive agent not only has excellent adhesion to Polyimide (PI) and LCP, but also has excellent adhesion to copper foil, solder heat resistance, and also exhibits good absorption of absorbance at 355nm as an index of laser processability. In contrast, in comparative example 1, since the polyimide resin (b) was not blended, the absorbance at 355nm was low, and the laser processability was poor. In comparative example 2, since the curing agent (c) was not blended, the solder heat resistance was poor. In comparative example 3, since the modified polyolefin resin (a) was not blended, the adhesiveness was poor. In comparative example 4, since the polyimide resin (b) does not contain polyolefin polyol, dimer acid derivative, or the like, the low dielectric characteristics and compatibility are poor. In comparative example 5, since the component (b) was a polyurethane resin containing no imide group, the absorbance at 355nm was low, and the laser processability was poor.

Industrial applicability

The adhesive composition of the present invention has high adhesion to not only conventional polyimide and liquid crystal polymer but also metal base materials such as copper foil, and can give high solder heat resistance, and further has excellent low dielectric characteristics and laser processability. The adhesive composition of the present invention can provide an adhesive sheet and a laminate obtained by bonding using the same. By virtue of the above characteristics, the composition is useful for flexible printed wiring board applications, particularly for FPC applications and electromagnetic wave shielding materials, where low dielectric characteristics (low dielectric constant, low dielectric loss tangent) are required in a high frequency region.

Claims

1. An adhesive composition comprising a modified polyolefin resin (a), a polyimide resin (b) and a curing agent (c),

2. The adhesive composition according to claim 1, wherein the acid value of the modified polyolefin resin (a) is 5 to 30mgKOH/g.

3. The adhesive composition according to claim 1 or 2, wherein the curing agent (c) comprises at least one selected from the group consisting of epoxy resin, polyisocyanate, and polycarbodiimide.

4. The adhesive composition according to claim 1 or 2, wherein the modified polyolefin resin (a) is contained in an amount of 50 to 95 parts by mass based on 100 parts by mass of the total of the modified polyolefin resin (a) and the polyimide resin (b).

5. The adhesive composition according to claim 1 or 2, wherein the relative dielectric constant at 10GHz is less than 3.0.

6. The adhesive composition according to claim 1 or 2, wherein the content of the curing agent (c) is 0.5 to 60 parts by mass based on 100 parts by mass of the total of the modified polyolefin resin (a) and the polyimide resin (b).

7. An adhesive sheet having a layer formed of the adhesive composition according to claim 1 or 2.

8. An electromagnetic wave shielding material, wherein there is a layer formed of the adhesive composition according to claim 1 or 2.

9. A laminate having a layer formed of the adhesive composition according to claim 1 or 2.

10. A printed wiring board comprising the laminate of claim 9 as a constituent element.