Polyolefin-based adhesive composition

Abstract

Provided is an adhesive composition which ensures high adhesion between a metal base and a nonpolar resin base such as a liquid crystal polymer, and has solder heat resistance and low dielectric properties, and which also has excellent pot life properties.　The adhesive composition contains: an acid-modified polyolefin (A) satisfying the following (1)-(3); and at least one selected from the group consisting of an epoxy resin (B1), an isocyanate compound (B2), and a carbodiimide compound (B3). (1) The acid value is 5-50 mgKOH / g. (2) The bonding ratio (molar ratio) between a carboxylic acid anhydride group and a dicarboxylic acid group is 100:0 to 50:50. (3) The total amount of the carboxylic acid anhydride group and the dicarboxylic acid group is 90 mol% or more when the whole acid component, which is bonded to the acid-modified polyolefin (A), is 100 mol%.

Description

Technical Field

[0001] The present invention relates to a polyolefin-based adhesive composition. More specifically, it relates to a polyolefin-based adhesive composition used for bonding a resin substrate to a resin substrate or a metal substrate. In particular, it relates to an adhesive composition for a flexible printed wiring board (hereinafter abbreviated as FPC), and a cover film, a laminate, a copper foil with resin, and a bonding sheet containing the same.

Background Art

[0002] Since a flexible printed wiring board (FPC) has excellent flexibility, it can cope with the multifunctionalization and miniaturization of personal computers (PCs), smartphones, etc., and is therefore widely used for incorporating an electronic circuit board into a narrow and complex interior. In recent years, the miniaturization, weight reduction, high density, and high output of electronic devices have advanced, and the requirements for the performance of wiring boards (electronic circuit boards) have become increasingly sophisticated due to these trends. In particular, with the speeding up of transmission signals in FPCs, the frequency of signals has been increasing. Along with this, the requirement for low dielectric characteristics (low dielectric constant, low dielectric tangent) in the high-frequency region for FPCs has been increasing. In order to achieve such low dielectric characteristics, measures have been taken to reduce the dielectric loss of the base material and adhesive of FPCs. As adhesives, combinations of acid-modified polyolefins and epoxy resins (Patent Document 1), combinations of acid-modified polyolefins and polyfunctional isocyanate compounds (Patent Document 2), thermosetting adhesive compositions containing acid-modified polyolefins, carbodiimide resins, polyfunctional epoxy resins, and fillers have been developed (Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Disclosure of the Invention

Problems to be Solved by the Invention

[0004] However, it has been found that although the polyolefin modified with maleic anhydride has carboxylic anhydride groups immediately after production, there is a problem that it absorbs moisture over time and the carboxylic anhydride ring opens. Therefore, as in Patent Documents 1 to 3, it has been found that when used without any moisture absorption countermeasures, the adhesiveness, solder heat resistance, dielectric properties (relative permittivity, dielectric loss tangent), and pot life properties are insufficient.

[0005] As a result of intensive studies to solve the above problems, the present invention includes an acid-modified polyolefin having a predetermined ratio of carboxylic anhydride groups, and further contains one or more selected from the group consisting of an epoxy resin, an isocyanate compound, and a carbodiimide compound. The adhesive composition exhibits excellent adhesiveness, solder heat resistance, and low dielectric properties (relative permittivity, dielectric loss tangent) between a resin base material and a metal base material, and further has excellent pot life properties after blending a curing agent, and thus the present invention has been completed.

[0006] That is, the object of the present invention is to provide an adhesive composition having good adhesiveness to both various resin base materials such as polyimide (PI) and liquid crystal polymer (LCP) and a metal base material, and also excellent in solder heat resistance, dielectric properties, and pot life properties.

Means for Solving the Problems

[0007] An adhesive composition containing an acid-modified polyolefin (A) satisfying the following (1) to (3), and further containing one or more selected from the group consisting of an epoxy resin (B1), an isocyanate compound (B2), and a carbodiimide compound (B3). (1) The acid value is 5 to 50 mgKOH / g (2) The bonding ratio (molar ratio) of the carboxylic anhydride group represented by the formula (a1) to the carboxylic acid group represented by the formula (a2) is formula (a1) / formula (a2)=100 / 0 to 50 / 50 (3) When the total acid components bonded to the acid-modified polyolefin (A) are 100 mol%, the total amount of the formula (a1) and the formula (a2) is 90 mol% or more.

Chemical formula

Chemical formula

[0008] The epoxy resin (B1) preferably contains a glycidylamine type epoxy resin (B11) and is further a mixture of one or more selected from the group consisting of a glycidyl ether type resin (B12) and an alicyclic epoxy resin (B13).

[0009] The isocyanate compound (B2) is preferably a polyfunctional isocyanate compound.

[0010] The carbodiimide compound (B3) is preferably a polyfunctional carbodiimide compound.

[0011] Furthermore, it preferably contains an oligophenylene ether (C) and preferably further contains an organic solvent.

[0012] The adhesive composition having a relative permittivity (ε c ) of 3.0 or less and a dielectric loss tangent (tan δ) of 0.02 or less at 1 GHz. An adhesive sheet or a laminate containing the adhesive composition. A printed wiring board including the laminate as a component. A cover film including the printed wiring board as a component.

Advantages of the Invention

[0013] The adhesive composition according to the present invention has good adhesiveness to both various resin substrates such as polyimide and metal substrates, and is excellent in solder heat resistance, low dielectric characteristics, and pot life.

Embodiments for Carrying Out the Invention

[0014] <Acid-modified polyolefin (A)> The acid-modified polyolefin (A) used in the present invention (hereinafter, also simply referred to as component (A)) satisfies the following requirements (1) to (3).

[0015] <Requirement (1)> From the viewpoints of solder heat resistance and adhesion to resin substrates and metal substrates, the acid value of the acid-modified polyolefin (A) needs to be 5 mgKOH / g or more at the lower limit. Since good compatibility with the epoxy resin (B1), isocyanate compound (B2), and carbodiimide compound (B3) can be achieved, excellent adhesive strength can be exhibited, and a high crosslinking density and good solder heat resistance can be obtained, it is preferably 6 mgKOH / g or more, more preferably 7 mgKOH / g or more, and still more preferably 8 mgKOH / g or more. Also, the upper limit needs to be 50 mgKOH / g. Since good adhesion and solder heat resistance can be achieved, and the viscosity and stability of the solution are good, excellent pot life properties can be exhibited, it is preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, and still more preferably 20 mgKOH / g or less. If within the above range, the manufacturing efficiency is also improved.

[0016] <Requirement (2)> The bonding ratio (molar ratio) of the carboxylic anhydride group represented by formula (a1) to the carboxylic acid group represented by formula (a2) needs to be formula (a1) / formula (a2) = 100 / 0 to 50 / 50. [Chemical formula] [Chemical formula] [In formula (a1) and formula (a2), * represents a bond that binds to the acid-modified polyolefin (A).]

[0017] Since the adhesiveness, solder heat resistance, and pot life are good, it is preferable that the formula (a1) is in excess of the formula (a2). It is preferable that formula (a1) / formula (a2) = less than 100 / more than 0 to more than 50 / less than 50, more preferably 99 / 1 to 55 / 45, still more preferably 97 / 3 to 60 / 40, even more preferably 95 / 5 to 65 / 35, particularly preferably 93 / 7 to 70 / 30, and most preferably 91 / 9 to 75 / 25.

[0018] The acid-modified polyolefin (A) has a carboxylic anhydride group, but gradually absorbs moisture through the processes of manufacturing, packaging, and storing the acid-modified polyolefin, and the carboxylic anhydride group undergoes ring-opening to become a carboxylic acid group. Therefore, in order to make the bonding ratio of the carboxylic anhydride group represented by formula (a1) and the carboxylic acid group represented by formula (a2) within the above range, for example, after manufacturing the acid-modified polyolefin (A), it is preferable to perform a dehydration condensation reaction again in an organic solvent such as toluene, or to perform dehydration condensation at a high temperature without a solvent.

[0019] The bonding ratio (molar ratio) of formula (a1) / formula (a2) can be measured by IR. Specifically, a calibration curve using maleic anhydride (hereinafter also referred to as maleic anhydride) as a standard substance is created, and it can be determined from the absorbance of the carbonyl (C=O) bond (around 1780 cm -1 -1) derived from the carboxylic anhydride group and the absorbance of the carbonyl (C=O) bond (around 1730 cm -1 -1) derived from the carboxylic acid group.

[0020] <Requirement (3)> When the total amount of the formulas (1) and (2) is 90 mol% or more based on 100 mol% of all acid components bonded to the acid-modified polyolefin (A). Since the adhesiveness, solder heat resistance, and pot life are good, it is preferably 92 mol% or more, more preferably 95 mol% or more, still more preferably 98 mol% or more, particularly preferably 99 mol% or more, and it may even be 100 mol%.

[0021] The acid-modified polyolefin (A) is preferably obtained by grafting at least one of maleic acid and maleic anhydride onto a polyolefin resin. The polyolefin resin refers to a polymer mainly composed of a hydrocarbon skeleton, such as a homopolymer of an olefin monomer exemplified by ethylene, propylene, butene, butadiene, isoprene, etc., or a copolymer with other monomers, and hydrides or halides of the obtained polymer. That is, the acid-modified polyolefin is preferably obtained by grafting at least one of maleic acid and maleic anhydride onto at least one of polyethylene, polypropylene, and propylene-α-olefin copolymer.

[0022] The propylene-α-olefin copolymer is obtained by copolymerizing α-olefin mainly with propylene. As the α-olefin, for example, one or several of ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate, etc. can be used. Among these α-olefins, ethylene and 1-butene are preferred, and 1-butene is more 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, and more preferably 70 mol% or more.

[0023] Examples of carboxylic acid components other than maleic acid and maleic anhydride include itaconic acid, citraconic acid and their acid anhydrides, acrylic acid, methacrylic acid, etc. Specific examples of the acid-modified polyolefin (A) include maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, maleic anhydride-modified propylene-ethylene-butene copolymer, etc. These acid-modified polyolefins can be used alone or in combination of two or more. Among them, maleic anhydride-modified propylene-butene copolymer is preferred.

[0024] The number average molecular weight (Mn) of the acid-modified polyolefin (A) is preferably in the range of 10,000 to 50,000. More preferably, it is 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 setting it to be not less than the lower limit value, the cohesive force becomes good, and excellent adhesiveness can be exhibited. Also, by setting it to be not more than the upper limit value, the fluidity is excellent and the operability becomes good.

[0025] The weight average molecular weight (Mw) of the acid-modified polyolefin (A) is preferably in the range of 40,000 to 180,000. More preferably, it is in the range of 50,000 to 160,000, still more preferably in the range of 60,000 to 150,000, particularly preferably in the range of 70,000 to 140,000, and most preferably in the range of 80,000 to 130,000. By setting it to be not less than the lower limit value, the cohesive force becomes good, and excellent adhesiveness can be exhibited. Also, by setting it to be not more than the upper limit value, the fluidity is excellent and the operability becomes good.

[0026] The acid-modified polyolefin (A) is preferably a crystalline acid-modified polyolefin. The crystallinity referred to in the present invention means that, using a differential scanning calorimeter (DSC), the temperature is raised from -100°C to 250°C at a rate of 20°C / min, and it refers to those showing a distinct melting peak during the temperature-raising process.

[0027] The melting point (Tm) of the acid-modified polyolefin (A) is preferably in the range of 50°C to 120°C. More preferably, it is in the range of 60°C to 100°C, and most preferably in the range of 70°C to 90°C. By setting it to be not less than the lower limit value, the cohesive force derived from crystals becomes good, and excellent adhesiveness and solder heat resistance can be exhibited. Also, by setting it to be not more than the upper limit value, the solution stability and fluidity are excellent, and the operability during adhesion becomes good.

[0028] The heat of fusion (ΔH) of the acid-modified polyolefin (A) is preferably in the range of 5 J / g to 60 J / g. More preferably, it is in the range of 10 J / g to 50 J / g, and still more preferably, it is in the range of 20 J / g to 40 J / g. By setting it to be equal to or higher than the lower limit value, the cohesive force derived from crystals becomes good, and excellent adhesiveness and solder heat resistance can be exhibited. Further, by setting it to be equal to or lower than the upper limit value, it is excellent in solution stability and fluidity, and the operability during adhesion becomes good.

[0029] The production method of the acid-modified polyolefin (A) is not particularly limited, and examples thereof include radical graft reaction (that is, a reaction in which radical species are generated with respect to the polymer serving as the main chain, and unsaturated carboxylic acids and acid anhydrides are graft-polymerized using the radical species as the polymerization initiation point), and the like.

[0030] The radical generator is not particularly limited, but it is preferable to use an organic peroxide. The organic peroxide is not particularly limited, and examples thereof include peroxides such as di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy pivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauroyl peroxide; and azo nitriles such as azobisisobutyronitrile and azobisisopropylnitrile.

[0031] <Epoxy resin (B1)> The epoxy resin (B1) used in the present invention (hereinafter, also simply referred to as the (B1) component) is not particularly limited as long as it has a glycidyl group in the molecule, but preferably has two or more glycidyl groups in the molecule.

[0032] The content of the epoxy resin (B1) is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A). Since a sufficient curing effect can be obtained and excellent adhesiveness and solder heat resistance can be exhibited, it is 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. Further, in addition to adhesiveness, solder heat resistance and pot life properties, since it has excellent low dielectric properties, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, still more preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less.

[0033] The epoxy equivalent of the epoxy resin (B1) is preferably 50 g / eq or more, more preferably 100 g / eq or more, and still more preferably 150 g / eq or more. Also, it is preferably 400 g / eq or less, more preferably 350 g / eq or less, and still more preferably 300 g / eq or less. By setting it within the above range, excellent solder heat resistance can be exhibited.

[0034] The epoxy resin (B1) used in the present invention preferably contains a glycidylamine type epoxy resin (B11) and is a mixture of one or more selected from the group consisting of a glycidyl ether type resin (B12) and an alicyclic epoxy resin (B13) from the viewpoints of adhesiveness and solder heat resistance. That is, it is preferably a mixture of (B11) and (B12), a mixture of (B11) and (B13), or a mixture of (B11), (B12) and (B13).

[0035] <Glycidylamine type epoxy resin (B11)> The glycidylamine type epoxy resin (B11) is not particularly limited as long as it is an amine type epoxy resin having one or more glycidyl groups in one molecule. It is preferably that the epoxy resin has 2 or more glycidyl groups in one molecule, more preferably 3 or more glycidyl groups in one molecule of the epoxy resin, and still more preferably 4 or more glycidyl groups in one molecule of the epoxy resin.

[0036] In addition, the glycidylamine type epoxy resin (B11) is preferable because the adhesiveness can be further improved by using a compound represented by the following general formula (b1).

Chemical formula

[0037] Specific examples of the glycidylamine type epoxy resin (B11) are not particularly limited, and examples thereof include glycidylamine-based resins such as tetraglycidyldiaminodiphenylmethane, triglycidyl p-aminophenol, tetraglycidyl bisaminomethylcyclohexanone, and N,N,N',N'-tetraglycidyl-m-xylenediamine. Among them, N,N,N',N'-tetraglycidyl-m-xylenediamine is preferable. These glycidylamine type epoxy resins (B11) can be used alone or in combination of two or more.

[0038] The compounding amount of the glycidylamine type epoxy resin (B11) is preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, further preferably 0.05 part by mass or more, particularly preferably 0.08 part by mass or more, and most preferably 0.1 part by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A) because the catalytic action is exhibited and the adhesiveness and solder heat resistance become good. Also, since the pot life property becomes good, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, further preferably 40 parts by mass or less, still more preferably 30 parts by mass or less, particularly preferably 20 parts by mass or less, and most preferably 15 parts by mass or less.

[0039] <Glycidyl ether type epoxy resin (B12)> The glycidyl ether type epoxy resin (B12) is not particularly limited as long as it is an epoxy resin having a glycidyl ether group in the molecule. Preferably, it is an epoxy resin having two or more glycidyl groups in one molecule of the epoxy resin, and more preferably, it is an epoxy resin having two or more glycidyl groups in one molecule of the epoxy resin and not containing a nitrogen atom.

[0040] The compounding amount of the glycidyl ether type epoxy resin (B12) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, further preferably 3 parts by mass or more, particularly preferably 4 parts by mass or more, and most preferably 5 parts by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A). Also, it is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, further preferably 16 parts by mass or less, particularly preferably 14 parts by mass or less, and most preferably 12 parts by mass or less. By setting it within the above range, excellent adhesiveness and solder heat resistance can be exhibited.

[0041] Specific examples of the glycidyl ether type epoxy resin (B12) are not particularly limited, but include phenol novolak type epoxy resin and cresol novolak type epoxy resin, which are preferable from the viewpoint of adhesiveness to a metal substrate. These glycidyl ether type epoxy resins (B12) can be used alone or in combination of two or more.

[0042] <Alicyclic epoxy resin (B13)> The alicyclic epoxy resin (B13) is not particularly limited as long as it is an epoxy resin having an alicyclic skeleton in the molecule. Preferably it is an alicyclic epoxy resin having two or more glycidyl groups in one molecule of the epoxy resin, and more preferably it is an alicyclic epoxy resin having two or more glycidyl groups in one molecule of the epoxy resin.

[0043] The blending amount of the alicyclic epoxy resin (B13) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, further preferably 3 parts by mass or more, particularly preferably 4 parts by mass or more, and most preferably 5 parts by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A). Also, it is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, further preferably 16 parts by mass or less, particularly preferably 14 parts by mass or less, and most preferably 12 parts by mass or less. By setting it within the above range, excellent adhesiveness and solder heat resistance can be exhibited.

[0044] Specific examples of the alicyclic epoxy resin (B13) are not particularly limited, and include dicyclopentadiene skeleton-containing epoxy resin, glycidyl ester of hexahydrophthalic acid, 3,4-epoxycyclohexylmethyl carboxylate, and the like. Among them, the dicyclopentadiene skeleton-containing epoxy resin is preferable. These alicyclic epoxy resins (B13) can be used alone or in combination of two or more.

[0045] By using in combination one or more selected from the group consisting of glycidylamine type epoxy resin (B11), glycidyl ether type resin (B12) and alicyclic epoxy resin (B13), excellent adhesiveness can be exhibited. That is, the glycidylamine type epoxy resin (B11) has a reaction and curing action with the acid-modified polyolefin (A), the glycidyl ether type epoxy resin (B12) and / or the alicyclic epoxy resin (B13). Further, the glycidylamine type epoxy resin (B11) has a reaction and curing catalyst action between the acid-modified polyolefin (A) and the glycidylamine type epoxy resin (B11), between glycidylamine type epoxy resins (B11), between glycidyl ether type epoxy resins (B12), between alicyclic epoxy resins (B13), and between the glycidylamine type epoxy resin (B11) and the glycidyl ether type epoxy resin (B12) and / or the alicyclic epoxy resin (B13). Therefore, excellent adhesiveness can be exhibited with non-polar resin substrates such as liquid crystal polymers and metal substrates in addition to polyimide.

[0046] When using in combination one or more selected from the group consisting of glycidylamine type epoxy resin (B11), glycidyl ether type epoxy resin (B12) and alicyclic epoxy resin (B13), the total content thereof is preferably 2 to 60 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 20 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin (A) from the viewpoints of adhesiveness, solder heat resistance and pot life.

[0047] The content of the glycidylamine type epoxy resin (B11) is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, and most preferably 3 to 10% by mass of the total epoxy resin (B1). By setting it to be not less than the lower limit value, the catalytic action is exhibited, and the adhesiveness and solder heat resistance are good. By setting it to be not more than the upper limit value, since the crosslinking reaction does not proceed excessively, the rigidity is not too high and the adhesiveness is good. Further, during the solution storage of the adhesive composition, the crosslinking reaction does not proceed too much and the pot life is also good.

[0048] As the epoxy resin (B1) used in the present invention, other epoxy resins can also be used. For example, biphenyl type epoxy resins, naphthalene type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, glycidyl ester types such as dimer acid glycidyl ester, triglycidyl isocyanurate, epoxidized polybutadiene, alicyclic or aliphatic epoxides such as epoxidized soybean oil, etc. can be mentioned, and they can be used alone or in combination of two or more.

[0049] <Isocyanate compound (B2)> The isocyanate compound (B2) used in the present invention (hereinafter, also simply referred to as the (B2) component) is preferably a polyfunctional isocyanate compound having two or more isocyanate groups in one molecule. Further, compounds derived from polyfunctional isocyanate compounds can also be used.

[0050] The content of the isocyanate compound (B2) is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A). Since a sufficient curing effect can be obtained and excellent adhesiveness and solder heat resistance can be exhibited, it is 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. Also, in addition to adhesiveness, solder heat resistance and pot life properties, since it has excellent low dielectric properties, it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, still more preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less.

[0051] The isocyanate compound (B2) can be any of an aromatic isocyanate compound, an alicyclic isocyanate compound, or an aliphatic isocyanate compound, and these can 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-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 1,8-naphthalene diisocyanate, 3,3'-biphenyl diisocyanate, 4,4'-biphenyl diisocyanate, 3,3'-dimethyl-4,4'-biphenyl diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, etc., and these can be used alone or in combination of two or more. Among them, 3,3'-dimethyl-4,4'-biphenyl diisocyanate 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, etc., and these can be used alone or in combination of two or more. The aliphatic isocyanate compound may be either a linear or branched aliphatic isocyanate. Preferably it is a linear aliphatic diisocyanate compound, specifically, 1,3-propanediisocyanate, 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., and these can be used alone or in combination of two or more. Among them, 1,6-hexamethylene diisocyanate is preferable.

[0052] The isocyanate compound (B2) may be an isocyanurate form, an adduct form, a biuret form, a uretdione form, or an allophanate form of the isocyanate compound. These compounds may be used alone or in combination of two or more. Among them, the isocyanurate form or the biuret form is preferable.

[0053] <Carbodiimide compound (B3)> The carbodiimide compound (B3) used in the present invention (hereinafter, also simply referred to as the (B3) component) is preferably a polyfunctional carbodiimide compound having two or more carbodiimide groups in one molecule. By using the carbodiimide compound (B3), the carboxylic anhydride group of the acid-modified polyolefin reacts with the carbodiimide, enhancing the interaction between the adhesive composition and the substrate, and improving the adhesiveness and soldering heat resistance.

[0054] The content of the carbodiimide compound (B3) is preferably 0.5 part by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A). Since a sufficient curing effect can be obtained and excellent adhesiveness and soldering heat resistance can be exhibited, it is 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. Further, in addition to adhesiveness, soldering heat resistance, and pot life properties, it has excellent low dielectric properties, so it is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, still more preferably 40 parts by mass or less, and particularly preferably 35 parts by mass or less.

[0055] The carbodiimide compound (B3) may be any of an aromatic carbodiimide compound, an alicyclic carbodiimide compound, or an aliphatic carbodiimide compound, and these can 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, polytolylene carbodiimide, poly(diisopropylphenylene carbodiimide), poly(methyldiisopropylphenylene carbodiimide), poly(4,4'-diphenylmethane carbodiimide), and the like. Examples of the alicyclic carbodiimide compound include poly-m-cyclohexyl carbodiimide, poly-p-cyclohexyl carbodiimide, poly(4,4'-dicyclohexylmethane carbodiimide), poly(3,3'-dicyclohexylmethane carbodiimide), and the like. The aliphatic carbodiimide compound may be either a linear or branched aliphatic carbodiimide compound. Preferably, it is a linear aliphatic carbodiimide compound, and specifically, examples include polymethylene carbodiimide, polyethylene carbodiimide, polypropylene carbodiimide, polybutylene carbodiimide, polypentamethylene carbodiimide, polyhexamethylene carbodiimide, and the like. These can be used alone or in combination of two or more. Among them, it is preferably an aromatic carbodiimide or an alicyclic carbodiimide.

[0056] <Oligophenylene ether (C)> By incorporating the oligophenylene ether (C) into the adhesive composition of the present invention, even more excellent solder heat resistance can be exhibited. The oligophenylene ether (C) (hereinafter, also simply referred to as component (C)) used in the present invention is not particularly limited, but is preferably a compound having a structural unit represented by the following general formula (c1) and / or a structural unit of general formula (c2). [Chemical formula]

[0057] In the general formula (c1), R1, R2, R3, and R4 are each independently preferably a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted aryl group, an optionally substituted aralkyl group, or an optionally substituted alkoxy group. The "alkyl group" of the optionally substituted alkyl group is, for example, a linear or branched alkyl group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. More specifically, examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, etc., and a methyl group or an ethyl group is more preferable. Examples of the "alkenyl group" of the optionally substituted alkenyl group include an ethenyl group, a 1-propenyl group, a 2-propenyl group, a 3-butenyl group, a pentenyl group, a hexenyl group, etc., and an ethenyl group or a 1-propenyl group is more preferable. Examples of the "alkynyl group" of the optionally substituted alkynyl group include an ethynyl group, a 1-propynyl group, a 2-propynyl (propargyl) group, a 3-butynyl group, a pentynyl group, a hexynyl group, etc., and an ethynyl group, a 1-propynyl group, or a 2-propynyl (propargyl) group is more preferable. Examples of the "aryl group" of the optionally substituted aryl group include a phenyl group, a naphthyl group, etc., and a phenyl group is more preferable. Examples of the "aralkyl group" of the optionally substituted aralkyl group include a benzyl group, a phenethyl group, a 2-methylbenzyl group, a 4-methylbenzyl group, an α-methylbenzyl group, a 2-vinylphenethyl group, a 4-vinylphenethyl group, etc., and a benzyl group is more preferable. The "alkoxy group" of the optionally substituted alkoxy group is, for example, a linear or branched alkoxy group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. For example, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, etc., and a methoxy group or an ethoxy group is more preferable.When the above alkyl group, aryl group, alkenyl group, alkynyl group, aralkyl group, and alkoxy group are substituted, they may have one or more substituents. Examples of such substituents include halogen atoms (e.g., fluorine atom, chlorine atom, bromine atom), alkyl groups having 1 to 6 carbon atoms (e.g., methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group), aryl groups (e.g., phenyl group, naphthyl group), alkenyl groups (e.g., ethenyl group, 1-propenyl group, 2-propenyl group), alkynyl groups (e.g., ethynyl group, 1-propynyl group, 2-propynyl group), aralkyl groups (e.g., benzyl group, phenethyl group), alkoxy groups (e.g., methoxy group, ethoxy group), and the like. Among them, it is preferable that R1 and R4 are methyl groups and R2 and R3 are hydrogen atoms.

[0058]

Chemical formula

[0059] The oligophenylene ether (C) may be partially or entirely a modified oligophenylene ether functionalized with an ethylenically unsaturated group such as a vinylbenzyl group, an epoxy group, an amino group, a hydroxy group, a mercapto group, a carboxyl group, and a silyl group, etc. Further, it is preferable that both ends have a hydroxy group, an epoxy group, or an ethylenically unsaturated group. Examples of the ethylenically unsaturated group include alkenyl groups such as an ethenyl group, an allyl group, a methacryl group, a propenyl group, a butenyl group, a hexenyl group, an octenyl group, etc., cycloalkenyl groups such as a cyclopentenyl group, a cyclohexenyl group, etc., and alkenylaryl groups such as a vinylbenzyl group, a vinylnaphthyl group, etc. Also, both ends may be the same functional group or different functional groups. From the viewpoint of highly controlling the balance of low dielectric tangent and reduction of resin residue, it is preferable that both ends are a hydroxy group or a vinylbenzyl group, and it is more preferable that both ends are a hydroxy group or a vinylbenzyl group.

[0060] As the compound having a structural unit represented by the general formula (c1), a compound of the general formula (c3) is particularly preferable. [Chemical formula] In the general formula (c3), n is preferably 3 or more, more preferably 5 or more, preferably 23 or less, more preferably 21 or less, and still more preferably 19 or less.

[0061] In addition, as the compound having the structural unit represented by the general formula (c2), the compound of the general formula (c4) is particularly preferable. [Chemical formula] In the general formula (c4), n is preferably 2 or more, more preferably 4 or more, preferably 23 or less, more preferably 20 or less, and still more preferably 18 or less.

[0062] The number average molecular weight of the oligophenylene ether (C) is preferably 3000 or less, more preferably 2700 or less, and still more preferably 2500 or less. Also, the number average molecular weight of the oligophenylene ether (C) is preferably 500 or more, more preferably 700 or more. By setting the number average molecular weight of the oligophenylene ether (C) to be not less than the lower limit value, the flexibility of the obtained adhesive layer can be improved. On the other hand, by setting the number average molecular weight of the oligophenylene ether (C) to be not more than the upper limit value, the solubility in an organic solvent can be improved.

[0063] The content of the oligophenylene ether (C) is preferably 0.05 part by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A). Since excellent solder heat resistance can be exhibited, it is more preferably 1 part by mass or more, and still more preferably 5 parts by mass or more. Also, it is preferably 200 parts by mass or less. Since excellent adhesiveness and solder heat resistance can be exhibited, it is more preferably 150 parts by mass or less, still more preferably 100 parts by mass or less, and particularly preferably 50 parts by mass or less.

[0064] <Adhesive composition> The adhesive composition of the present invention contains an acid-modified polyolefin (A) that satisfies the specific requirements, and further contains at least one selected from the group consisting of an epoxy resin (B1), an isocyanate compound (B2), and a carbodiimide compound (B3), and preferably further contains the oligophenylene ether (C). The adhesive composition of the present invention has excellent adhesiveness not only to polyimide but also to low-polarity resin substrates such as liquid crystal polymers and metal substrates, and can further exhibit solder heat resistance, pot life properties, and electrical properties (low dielectric properties). That is, when the adhesive composition is applied to a substrate, the cured adhesive coating film (adhesive layer) can exhibit excellent low dielectric constant properties.

[0065] The total amount of maleic acid and maleic anhydride contained in the adhesive composition is preferably 1% by mass or less. Since adhesiveness, solder heat resistance, and pot life properties are good, it is more preferably 0.8% by mass or less, still more preferably 0.6% by mass or less, and particularly preferably 0.4% by mass or less. Although it is preferable that the total of maleic anhydride and maleic acid is as small as possible, industrially, it may be 0.01% by mass or more, and it may be 0.1% by mass or more.

[0066] The adhesive composition according to the present invention preferably has a relative dielectric constant (ε c ) of 3.0 or less at a frequency of 1 GHz. More preferably, it is 2.6 or less, and still more preferably 2.3 or less. The lower limit is not particularly limited, but is 2.0 in practical use. Also, the relative dielectric constant (ε c ) in the entire region from 1 GHz to 60 GHz is preferably 3.0 or less, more preferably 2.6 or less, and still more preferably 2.3 or less.

[0067] The adhesive composition according to the present invention preferably has a dielectric loss tangent (tanδ) of 0.02 or less at a frequency of 1 GHz. More preferably, it is 0.01 or less, and even more preferably 0.008 or less. The lower limit is not particularly limited, but is 0.0001 in practical use. Also, it is preferable that the dielectric loss tangent (tanδ) is 0.02 or less in the entire frequency range of 1 GHz to 60 GHz, more preferably 0.01 or less, and even more preferably 0.008 or less.

[0068] In the present invention, the relative permittivity (ε c ) and the dielectric loss tangent (tanδ) can be measured as follows. That is, the adhesive composition is applied to a release substrate so that the dried thickness becomes 25 μm, and dried at about 130°C for about 3 minutes. Then, it is heat-treated at about 140°C for about 4 hours to be cured, and the cured adhesive composition layer (adhesive layer) is peeled from the release film. The relative permittivity (ε c ) and the dielectric loss tangent (tanδ) of the adhesive composition layer after peeling are measured at a frequency of 1 GHz. Specifically, the relative permittivity (ε c ) and the dielectric loss tangent (tanδ) can be calculated from the measurement by the cavity resonator perturbation method.

[0069] <Organic solvent> The adhesive composition of the present invention can further contain an organic solvent. The organic solvent used in the present invention is not particularly limited as long as it can dissolve the acid-modified polyolefin (A), epoxy resin (B1), isocyanate compound (B2), carbodiimide compound (B3), and oligophenylene ether (C). Specifically, for example, aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as hexane, heptane, octane, and decane, alicyclic hydrocarbons such as cyclohexane, cyclohexene, methylcyclohexane, and ethylcyclohexane, halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform, alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol, ketone solvents such as acetone, methyl isobutyl ketone, 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, glycol ether solvents such as 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, and tetraethylene glycol mono-n-butyl ether can be used, and one or more of these can be used in combination. Particularly, from the viewpoints of working environment and drying property, methylcyclohexane and toluene are preferred.

[0070] 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 with respect to 100 parts by mass of the acid-modified olefin (A). By setting it to be not less than the lower limit value, the liquid state and pot life property become good. Also, by setting it to be not more than the upper limit value, it is advantageous in terms of manufacturing cost and transportation cost.

[0071] From the viewpoints of the solution state and pot life property of the adhesive composition, a mixed liquid of one or more solvents (D1) selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons and halogenated hydrocarbons, and one or more solvents (D2) selected from the group consisting of alcoholic solvents, ketone solvents, ester solvents and glycol ether solvents is preferred. As the mixing ratio, it is preferably solvent (D1) / solvent (D2) = 50 to 97 / 50 to 3 (mass ratio), more preferably 55 to 95 / 45 to 5 (mass ratio), still more preferably 60 to 90 / 40 to 10 (mass ratio), and particularly preferably 70 to 80 / 30 to 20 (mass ratio). By setting it within the above range, the solution state and pot life property of the adhesive composition become good. Further, it is particularly preferable that the solvent (D1) is an aromatic hydrocarbon or an alicyclic hydrocarbon, and the solvent (D2) is a ketone solvent.

[0072] In addition, the adhesive composition of the present invention may further contain other components as necessary within a range not impairing the effects of the present invention. Specific examples of such components include flame retardants, tackifiers, fillers, and silane coupling agents.

[0073] <Flame retardant> The adhesive composition of the present invention may be blended with a flame retardant as necessary within a range not impairing the effects of the present invention. Examples of the flame retardant include bromine-based, phosphorus-based, nitrogen-based, metal hydroxide compounds, etc. Among them, phosphorus-based flame retardants are preferred, and known phosphorus-based flame retardants such as phosphate esters, for example, trimethyl phosphate, triphenyl phosphate, tricresyl phosphate, etc., phosphates, for example, aluminum phosphinate, etc., phosphazenes can be used. These may be used alone or in any combination of two or more. When containing a flame retardant, it is preferably contained 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 with respect to 100 parts by mass in total of the components (A) to (C). By setting it above the lower limit value, the flame retardancy becomes good. Further, by setting it below the upper limit value, the adhesiveness, solder heat resistance, electrical characteristics, etc. do not deteriorate.

[0074] <Adhesion promoter> In the adhesive composition of the present invention, an adhesion promoter may be blended as needed within a range that does not impair the effects of the present invention. Examples of the adhesion promoter include polyterpene resin, rosin resin, aliphatic petroleum resin, alicyclic petroleum resin, copolymer petroleum resin, styrene resin, and hydrogenated petroleum resin, etc., and they are used for the purpose of improving the adhesive strength. These may be used alone or in any combination of two or more. When containing an adhesion promoter, it is preferably contained 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 with respect to 100 parts by mass in total of the components (A) to (C). By setting it to be equal to or higher than the lower limit value, the effect of the adhesion promoter can be achieved. Also, by setting it to be equal to or lower than the upper limit value, the adhesiveness, solder heat resistance, electrical properties, etc. will not deteriorate.

[0075] <Filler> In the adhesive composition of the present invention, a filler such as silica may be blended as needed within a range that does not impair the effects of the present invention. Blending silica is very preferable because the characteristics of solder heat resistance are improved. Generally, hydrophobic silica and hydrophilic silica are known as silica, but here, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, etc. is better in terms of imparting moisture absorption resistance. When containing silica, its content is preferably in the range of 0.05 to 30 parts by mass with respect to 100 parts by mass in total of the components (A) to (C). By setting it to be equal to or higher than the lower limit value, the effect of improving solder heat resistance can be achieved. Also, by setting it to be equal to or lower than the upper limit value, poor dispersion of silica does not occur, the solution viscosity is good, and the workability is good. Also, the adhesiveness does not decrease.

[0076] <Silane coupling agent> In the adhesive composition of the present invention, a silane coupling agent may be blended as necessary within a range that does not impair the effects of the present invention. Blending a silane coupling agent is very preferable because it improves the adhesion to metals and the characteristics of solder heat resistance. The silane coupling agent is not particularly limited, and examples include those having an unsaturated group, those having a glycidyl group, and those having an amino group. Among these, from the viewpoint of solder heat resistance, silane coupling agents having a glycidyl group such as γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltriethoxysilane are more preferable. When the silane coupling agent is contained, its content is preferably in the range of 0.5 to 20 parts by mass with respect to 100 parts by mass in total of the components (A) to (C). By setting it to 0.5 part by mass or more, excellent solder heat resistance becomes good. On the other hand, by setting it to 20 parts by mass or less, solder heat resistance and adhesiveness become good.

[0077] <Laminated body> The laminated body of the present invention is one in which the adhesive composition is laminated on a base material (a two-layer laminated body of a base material / adhesive layer), or one in which another base material is further laminated (a three-layer laminated body of a base material / adhesive layer / base material). Here, the adhesive layer refers to a layer of the adhesive composition after the adhesive composition of the present invention is applied to the base material and dried. The laminated body of the present invention can be obtained by applying the adhesive composition of the present invention to various base materials according to a conventional method, drying it, and further laminating another base material.

[0078] <Base material> In the present invention, the base material is not particularly limited as long as it can form an adhesive layer by applying and drying the adhesive composition of the present invention, and examples include resin base materials such as film-shaped resins, metal base materials such as metal plates and metal foils, and papers.

[0079] Examples of the resin substrate include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluororesin. Preferably, it is a film-shaped resin (hereinafter also referred to as a substrate film layer).

[0080] As the metal substrate, any conventionally known conductive material that can be used for a circuit board can be used. Examples of the material include various metals such as SUS, copper, aluminum, iron, steel, zinc, nickel, and their respective alloys, plated products, and metals treated with other metals such as zinc and chromium compounds. Preferably, it is a metal foil, more preferably a copper foil. There is no particular limitation on the thickness of the metal foil, but preferably it is 1 μm or more, more preferably 3 μm or more, and even more preferably 10 μm or more. Also, preferably it is 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit. On the other hand, if the thickness is too thick, the processing efficiency during circuit production may decrease. The metal foil is usually provided in a roll form. The form of the metal foil used when manufacturing the printed wiring board of the present invention is not particularly limited. When using a ribbon-shaped metal foil, its length is not particularly limited. Also, its width is not particularly limited, but preferably it is about 250 to 500 cm.

[0081] Examples of the paper include high-quality paper, kraft paper, roll paper, and glassine paper. Examples of the composite material include glass epoxy.

[0082] From the adhesive strength and durability with the adhesive composition, as the substrate, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, fluororesin, SUS steel plate, copper foil, aluminum foil, or glass epoxy is preferred.

[0083] <Subsequent sheet> In the present invention, the adhesive sheet is formed by laminating the laminate and the release substrate via an adhesive composition. Specific configurations include laminate / adhesive layer / release substrate, or release substrate / adhesive layer / laminate / adhesive layer / release substrate. By laminating the release substrate, it functions as a protective layer for the substrate. Also, by using the release substrate, the release substrate can be peeled off from the adhesive sheet, and the adhesive layer can be transferred to another substrate.

[0084] The adhesive sheet of the present invention can be obtained by applying and drying the adhesive composition of the present invention to various laminates according to a conventional method. Also, after drying, when a release substrate is attached to the adhesive layer, it can be wound up without causing back transfer to the substrate, which is excellent in operability. Since the adhesive layer is protected, it is excellent in storage stability and easy to use. Also, after applying and drying on the release substrate, if another release substrate is attached as needed, it is possible to transfer the adhesive layer itself to another substrate.

[0085] <Release substrate> The release substrate is not particularly limited. For example, coating layers of blocking agents such as clay, polyethylene, and polypropylene are provided on both sides of papers such as high-quality paper, kraft paper, roll paper, and glassine paper, and silicone-based, fluorine-based, and alkyd-based release agents are further coated on each coating layer. Also, various olefin films alone such as polyethylene, polypropylene, ethylene-α-olefin copolymer, and propylene-α-olefin copolymer, and those with the above release agent coated on films such as polyethylene terephthalate are included. Due to reasons such as the release force between the release substrate and the adhesive layer and the adverse effect of silicone on electrical properties, those with polypropylene blocking treatment on both sides of high-quality paper and using an alkyd-based release agent thereon, or those using an alkyd-based release agent on polyethylene terephthalate are preferred.

[0086] In the present invention, the method of coating the adhesive composition on the substrate is not particularly limited, and examples thereof include comma coaters, reverse roll coaters, etc. Alternatively, if necessary, an adhesive layer can be provided directly or by a transfer method on a rolled copper foil or a polyimide film, which are constituent materials of a printed wiring board. The thickness of the adhesive layer after drying can be appropriately changed as necessary, but is preferably in the range of 5 to 200 μm. If the adhesive film thickness is less than 5 μm, the adhesive strength is insufficient. If it is 200 μm or more, there is a problem that drying is insufficient, the amount of residual solvent increases, and blisters are generated during the pressing of the printed wiring board. The drying conditions are not particularly limited, but the residual solvent rate after drying is preferably 1% by mass or less. If it exceeds 1% by mass, there is a problem that the residual solvent foams during the pressing of the printed wiring board and blisters are generated.

[0087] <Printed Wiring Board> The "printed wiring board" in the present invention includes, as a constituent element, a laminate formed from a metal foil forming a conductor circuit and a resin substrate. The 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 (FPCs), flat cables, circuit boards for tape automated bonding (TAB), etc., in which the conductor circuit formed by the metal foil is partially or entirely covered with a cover film, screen printing ink, etc., are collectively referred to.

[0088] The printed wiring board of the present invention can have any laminated structure that can be adopted 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. Also, for example, it can be a printed wiring board composed of five layers: a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

[0089] Furthermore, if necessary, the above-mentioned printed wiring boards can be laminated in two or three or more layers.

[0090] 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 with conventional polyimide, polyester film, and copper foil constituting the printed wiring board, but also with low-polarity resin substrates such as LCP, and can obtain solder reflow resistance, and the adhesive layer itself has excellent low dielectric characteristics. Therefore, it is suitable as an adhesive composition used for a cover film, a laminate, a copper foil with resin, and a bonding sheet.

[0091] In the printed wiring board of the present invention, as the base film, any resin film conventionally used as the base of the printed wiring board can be used. Examples of the resin of the base film include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluororesin. In particular, it has excellent adhesiveness even to low-polarity substrates such as liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, and polyolefin resin.

[0092] <Cover film> As the cover film, any insulating film conventionally known as an insulating film for a printed wiring board can be used. For example, films made of various polymers such as polyimide, polyester, polyphenylene sulfide, polyethersulfone, polyetheretherketone, aramid, polycarbonate, polyarylate, polyamideimide, liquid crystal polymer, syndiotactic polystyrene, and polyolefin resin can be used. More preferably, it is a polyimide film or a liquid crystal polymer film.

[0093] The printed wiring board of the present invention can be manufactured using any conventionally known process except using the materials of the above-described respective layers.

[0094] In a preferred embodiment, 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 is manufactured. On the other hand, a semi-finished product in which a metal foil layer is laminated on a base film layer to form a desired circuit pattern (hereinafter referred to as "base film side two-layer semi-finished product") or a semi-finished product in which an adhesive layer is laminated on a base film layer and a metal foil layer is laminated thereon to form a desired circuit pattern (hereinafter referred to as "base film side three-layer semi-finished product") is manufactured (hereinafter, the base film side two-layer semi-finished product and the base film side three-layer semi-finished product are collectively referred to as "base film side semi-finished product"). By laminating the thus obtained cover film side semi-finished product and the base film side semi-finished product, a four-layer or five-layer printed wiring board can be obtained.

[0095] The base film side semi-finished product is obtained, for example, by a manufacturing method including: (A) a step of applying a solution of a resin to be a base film to the metal foil and initially drying the coating film; and (B) a step of heat-treating and drying the laminate of the metal foil and the initially dried coating film obtained in (A) (hereinafter referred to as "heat treatment and solvent removal step").

[0096] For forming a circuit in the metal foil layer, a conventionally known method can be used. An active method may be used, or a subtractive method may be used. Preferably, it is a subtractive method.

[0097] The obtained base film side semi-finished product may be directly used for laminating with the cover film side semi-finished product, or may be used for laminating with the cover film side semi-finished product after laminating a release film for storage.

[0098] The cover film side semi-finished product is manufactured, for example, by applying an adhesive to a cover film. If necessary, a cross-linking reaction in the applied adhesive can be carried out. In a preferred embodiment, the adhesive layer is semi-cured.

[0099] The obtained cover film side semi-finished product may be directly used for laminating with the base film side semi-finished product, or may be used for laminating with the base film side semi-finished product after laminating and storing with a release film.

[0100] The base film side semi-finished product and the cover film side semi-finished product are each stored in the form of a roll, for example, and then laminated to produce a printed wiring board. As a lamination method, any method can be used. For example, they can be laminated using a press or a roll. Also, they can be laminated while heating by methods such as using a hot press or a heating roll device.

[0101] In the case of a reinforcing material side semi-finished product made of a flexible reinforcing material that can be wound, such as a polyimide film, it is preferably manufactured by applying an adhesive to the reinforcing material. Also, in the case of a reinforcing plate that cannot be wound hard, such as a metal plate of SUS, aluminum, etc., or a plate obtained by curing glass fibers with an epoxy resin, it is preferably manufactured by transfer coating an adhesive previously applied to a release base material. Also, if necessary, a cross-linking reaction can be performed on the applied adhesive. In a preferred embodiment, the adhesive layer is semi-cured.

[0102] The obtained reinforcing material side semi-finished product may be directly used for laminating with the back surface of the printed wiring board, or may be used for laminating with the base film side semi-finished product after laminating and storing with a release film.

[0103] The base film side semi-finished product, the cover film side semi-finished product, and the reinforcing material side semi-finished product are all laminates for printed wiring boards in the present invention.

[0104] <Example> Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples. In the examples and comparative examples, "parts" simply indicates parts by mass. Note that Examples 2, 3, 15, 16, 26, and 27 are reference examples.

[0105] (Physical property evaluation method)

[0106] (1) Acid value (mgKOH / g) The acid value (mgKOH / g) in the present invention was obtained by dissolving the acid-modified polyolefin in toluene and titrating it with a methanol solution of sodium methoxide using phenolphthalein as an indicator.

[0107] (2) Number average molecular weight (Mn), weight average molecular weight (Mw) The number average molecular weight in the present invention is a value measured by gel permeation chromatography manufactured by Shimadzu Corporation (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).

[0108] (3) Measurement of melting point (Tm) and heat of fusion (ΔH) The melting point and heat of fusion in the present invention were measured from the top temperature and area of the melting peak when the temperature was raised for melting, cooled to resinify, and then the temperature was raised again for melting at a rate of 20 °C / min using a differential scanning calorimeter (hereinafter referred to as DSC, manufactured by TA Instruments Japan, Q-2000).

[0109] (4) Measurement of the bonding ratio of carboxylic anhydride groups (a1) and carboxylic acid groups (a2) [Preparation of calibration curve solution] Weigh accurately 0.050 ± 0.001 g of maleic anhydride, dissolve it in chloroform, and make the volume up to 50 ml to prepare a solution A of 1.000 g / l. Dilute solution A by a factor of 2 to prepare a solution B of 0.500 g / l. Dilute solution B by a factor of 4 to prepare a solution C of 0.125 g / l. [Preparation of calibration curve] Using an infrared spectrophotometer (manufactured by Shimadzu Corporation, FT-IR8200PC), measure the absorption spectrum (Abs) in the order of blank solution (chloroform), solution C, solution B, and solution A. At 1780 cm of each spectrum -1Read the maximum absorption intensity in the vicinity, plot a calibration curve with the maleic anhydride concentration on the vertical axis and the intensity on the horizontal axis, and determine the slope (1 / a). [Preparation and Measurement of Sample Solution] Precisely weigh 0.50 ± 0.01 g of the sample (acid-modified polyolefin (A)), add 6.7 ml of chloroform and dissolve it to prepare a sample solution. Using an infrared spectrophotometer, measure the absorption spectrum (Abs) of the sample solution. At 1780 cm -1 in the vicinity (carboxylic acid anhydride group (a1)) and 1730 cm -1 Read the maximum absorption intensity in the vicinity (carboxylic acid group (a2)), and determine the content (mmol / g) per 1 g of the resin of (a1) and (a2) from the calibration curve. [Calculation] Calculation formula 1: Content of carboxylic acid anhydride group (a1) (mmol / g) = H1 × (1 / a) / C ÷ 99 × 1000 Calculation formula 2: Content of carboxylic acid group (a2) (mmol / g) = H2 × 2.08 × (1 / a) / C ÷ 117 × 1000 H1: Intensity (Abs) of the maximum absorption at 1780 cm -1 in the vicinity H2: Intensity (Abs) of the maximum absorption at 1730 cm -1 in the vicinity 2.08: Conversion coefficient for replacing the absorption of maleic acid with the absorption of maleic anhydride 1 / a: Slope of the calibration curve C: Concentration (mass%) of acid-modified polyolefin (A) in the sample solution

[0110] (5) Measurement of the total amount of (a1) and (a2) in all acid components bonded to acid-modified polyolefin (A) 400 MHz 1 H-nuclear magnetic resonance spectrometer 1 H-NMR) was used to quantitatively determine the molar ratio of the carboxylic acid anhydride group (a1), carboxylic acid group (a2), and other acids (such as acrylic acid) in acid-modified polyolefin (A). Deuterated chloroform was used as the solvent.

[0111] (6) Peel strength (adhesion) The adhesive composition described below was applied to a polyimide film with a thickness of 12.5 μm (manufactured by Kaneka Corporation, Apical (registered trademark)) or an LCP film with a thickness of 25 μm (manufactured by Kuraray Co., Ltd., Vector (registered trademark)) so that the thickness after drying would be 25 μm, and then dried at 130°C for 3 minutes. The adhesive film (B-stage product) thus obtained was laminated with a rolled copper foil with a thickness of 18 μm (manufactured by JX Metals Co., Ltd., BHY series). The lamination was carried out with the shiny surface of the rolled copper foil in contact with the adhesive layer, and pressed at 160°C under a pressure of 40 kgf / cm 2 for 30 seconds to adhere. Then, heat treatment was carried out at 140°C for 4 hours to cure, and a sample for peel strength evaluation was obtained. The peel strength was measured by performing a 90° peel test at 25°C with film pulling and a pulling speed of 50 mm / min. This test indicates the adhesive strength at room temperature. <Evaluation Criteria> ◎: 1.0 N / mm or more ○: 0.8 N / mm or more and less than 1.0 N / mm △: 0.5 N / mm or more and less than 0.8 N / mm ×: Less than 0.5 N / mm

[0112] (7) Solder Heat Resistance Samples were prepared in the same manner as above, and a 2.0 cm × 2.0 cm sample piece was subjected to an aging treatment at 23°C for 2 days, floated in a solder bath melted at 280°C for 10 seconds, and the presence or absence of appearance changes such as swelling was confirmed. <Evaluation Criteria> ◎: No swelling ○: Some swelling △: Many swellings ×: Swelling and discoloration

[0113] (8) Relative Dielectric Constant (ε c ) and Dissipation Factor (tanδ) The adhesive composition described below was applied to a Teflon (registered trademark) sheet with a thickness of 100 μm so that the thickness after drying and curing would be 25 μm, and dried at 130°C for 3 minutes. Then, it was heat-treated at 140°C for 4 hours to cure it, and after peeling off the Teflon (registered trademark) sheet, an adhesive resin sheet for testing was obtained. The obtained adhesive resin sheet for testing was cut into 8 cm × 3 mm strip-shaped samples to obtain test samples. The relative permittivity (ε c ) and the dielectric loss tangent (tanδ) were measured using a network analyzer (manufactured by Anritsu Corporation) under the conditions of a temperature of 23°C and a frequency of 1 GHz by the cavity resonator perturbation method. The obtained relative permittivity and dielectric loss tangent were evaluated as follows. <Evaluation Criteria for Relative Permittivity> ◎: 2.3 or less ○: Exceeding 2.3 and 2.6 or less △: Exceeding 2.6 and 3.0 or less ×: Exceeding 3.0 <Evaluation Criteria for Dielectric Loss Tangent> ◎: 0.008 or less ○: Exceeding 0.008 and 0.01 or less △: Exceeding 0.01 and 0.02 or less ×: Exceeding 0.02

[0114] (9) Pot life property The pot life property refers to the stability of a resin solution (varnish) prepared by blending component (A), component (B), and, if necessary, component (C), and a mixed solvent of methylcyclohexane, methyl ethyl ketone, and toluene (methylcyclohexane / methyl ethyl ketone / toluene = 72 / 8 / 20 (v / v)) so that the solid content concentration is 20% by mass, immediately after blending or after a certain period of time has elapsed since blending. When the pot life property is good, it means that the viscosity increase of the varnish is small and it can be stored for a long time. When the pot life property is poor, the viscosity of the varnish increases (thickens), and in severe cases, a gelation phenomenon occurs, making it difficult to apply to the substrate and impossible to store for a long time. The varnish prepared according to the ratios in Tables 2 to 4 was measured for the viscosity of the dispersion at 25°C using a Brookfield viscometer (rotor No. 2, rotation speed 60 rpm) to obtain the initial dispersion viscosity ηB0. Thereafter, the varnish was stored at 25°C for 7 days, and the dispersion viscosity ηB was measured at 25°C. The varnish viscosity was calculated by the following formula and evaluated as follows. Solution viscosity ratio = solution viscosity ηB / solution viscosity ηB0 <Evaluation criteria> ◎: 0.5 or more and less than 1.5 ○: 1.5 or more and less than 2.0 △: 2.0 or more and less than 3.0 ×: 3.0 or more, or viscosity measurement impossible due to gelling

[0115] (Acid-modified polyolefin (A)) Production Example 1 (Production of acid-modified polyolefins PO-1a and PO-1b) 100 parts by mass of a propylene-butene copolymer (Tafmer (registered trademark) XM7080 manufactured by Mitsui Chemicals), 20 parts by mass of maleic anhydride, and 6 parts by mass of di-tert-butyl peroxide were kneaded and reacted using a twin-screw extruder with the maximum temperature in the cylinder section set at 170°C. Thereafter, vacuum degassing was performed in the extruder to remove the remaining unreacted substances, and an anhydrous maleic acid-modified propylene-butene copolymer (PO-1a, acid value 25 mgKOH / g, number average molecular weight 25,000, weight average molecular weight 80,000, Tm 75°C, ΔH 30 J / g, bonding ratio of carboxylic acid anhydride group (a1) / carboxylic acid group (a2) = 89 / 11, total amount of (a1) and (a2) in all acid components 100 mol%) was obtained. Next, PO-1a was left standing in a desiccator at 30°C and 70% RH for 1 week to obtain P0-1b. PO-1b had a bonding ratio of carboxylic acid anhydride group (a1) / carboxylic acid group (a2) = 15 / 85.

[0116] Production Example 2 (Production of acid-modified polyolefins PO-2a and PO-2b) By the same procedure as in Production Example 1 except that the charged amount of maleic anhydride was changed to 25 parts by mass, a maleic anhydride-modified propylene-butene copolymer (PO-2a, acid value: 48 mgKOH / g, number-average molecular weight: 17,000, weight-average molecular weight: 50,000, Tm: 75 °C, ΔH: 25 J / g, bonding ratio of carboxylic anhydride group (a1) / carboxylic acid group (a2) = 88 / 12, total amount of (a1) and (a2) in all acid components: 100 mol%) was obtained. Next, PO-2a was allowed to stand in a desiccator at 30 °C and RH 70% for 1 week to obtain P0-2b. The bonding ratio of carboxylic anhydride group (a1) / carboxylic acid group (a2) of PO-2b was 13 / 87.

[0117] Production Example 3 (Production of acid-modified polyolefins PO-3a and PO-3b) By the same procedure as in Production Example 1 except that the charged amount of maleic anhydride was changed to 6 parts by mass, a maleic anhydride-modified propylene-butene copolymer (PO-3a, acid value: 7 mgKOH / g, number-average molecular weight: 35,000, weight-average molecular weight: 130,000, Tm: 82 °C, ΔH: 25 J / g, bonding ratio of carboxylic anhydride group (a1) / carboxylic acid group (a2) = 90 / 10, total amount of (a1) and (a2) in all acid components: 100 mol%) was obtained. Next, PO-3a was allowed to stand in a desiccator at 30 °C and RH 70% for 1 week to obtain P0-3b. The bonding ratio of carboxylic anhydride group (a1) / carboxylic acid group (a2) of PO-3b was 17 / 83.

[0118] Production Example 4 (Production of acid-modified polyolefins PO-4a and PO-4b) By the same procedure as in Production Example 1 except that the charged amount of maleic anhydride was changed to 30 parts by mass, a maleic anhydride-modified propylene-butene copolymer (PO-4a, acid value: 55 mgKOH / g, number-average molecular weight: 13,000, weight-average molecular weight: 40,000, Tm: 70 °C, ΔH: 25 J / g, bonding ratio of carboxylic anhydride group (a1) / carboxylic acid group (a2) = 88 / 12, total amount of (a1) and (a2) in all acid components: 100 mol%) was obtained. Next, PO-4b was allowed to stand in a desiccator at 30 °C and 70% RH for one week to obtain P0-4b. The ratio of the carboxylic anhydride group (a1) / carboxylic acid group (a2) of PO-4b was 12 / 88.

[0119] Production Example 5 (Production of acid-modified polyolefins PO-5a and PO-5b) An acid-modified propylene-butene copolymer (PO-5a, acid value 3 mg KOH / g, number average molecular weight 60,000, weight average molecular weight 200,000, Tm 80 °C, ΔH 25 J / g, ratio of carboxylic anhydride group (a1) / carboxylic acid group (a2) = 90 / 10, total amount of (a1) and (a2) in all acid components 100 mol%) was obtained in the same manner as in Production Example 1 except that the charged amount of maleic anhydride was changed to 2 parts by mass and the charged amount of di-tert-butyl peroxide was changed to 0.5 part by mass. Next, PO-5a was allowed to stand in a desiccator at 30 °C and 70% RH for one week to obtain P0-5b. The ratio of the carboxylic anhydride group (a1) / carboxylic acid group (a2) of PO-5b was 18 / 82.

[0120] Production Example 6 (Production of acid-modified polyolefin PO-6a) 100 parts by mass of a propylene-butene copolymer (“Tafmer (registered trademark) XM7080” manufactured by Mitsui Chemicals, Inc.), 20 parts by mass of maleic anhydride, 5 parts by mass of acrylic acid, and 6 parts by mass of di-tert-butyl peroxide were kneaded and reacted using a twin-screw extruder with the maximum temperature in the cylinder section set at 170 °C. Then, vacuum degassing was performed in the extruder to remove the remaining unreacted substances, and an acid-modified propylene-butene copolymer of maleic anhydride and acrylic acid (PO-6a, acid value 30 mg KOH / g, number average molecular weight 25,000, weight average molecular weight 80,000, Tm 75 °C, ΔH 30 J / g, ratio of carboxylic anhydride group (a1) / carboxylic acid group (a2) = 89 / 11, total amount of (a1) and (a2) in all acid components 70 mol%) was obtained. Next, PO-6a was allowed to stand in a desiccator at 30 °C and 70% RH for one week to obtain P0-6b. The ratio of the carboxylic anhydride group (a1) / carboxylic acid group (a2) of PO-6b was 14 / 86.

[0121] Preparation Example 1 (Cyclization Reaction of Acid-Modified Polyolefin PO-1c1) 100 parts by mass of PO-1b and 500 parts by mass of toluene were charged into a four-necked flask equipped with a Dean-Stark apparatus and a stirrer, and reacted under reflux for 5 hours. After cooling, it was poured into a container containing a large amount of methyl ethyl ketone to precipitate the resin (PO-1c1). PO-1c1 had an acid value of 25 mgKOH / g, a number average molecular weight of 25,000, a weight average molecular weight of 80,000, a Tm of 75 °C, a ΔH of 30 J / g, a bonding ratio of carboxylic anhydride group (a1) / carboxylic acid group (a2) = 100 / 0, and a total amount of (a1) and (a2) in all acid components of 100 mol%.

[0122] Preparation Examples 2 to 9 (Cyclization Reactions of Acid-Modified Polyolefins PO-1c2 to PO-6c1) The type of acid-modified polyolefin and the reflux time were changed as shown in Table 1, and Preparation Examples 2 to 9 were carried out in the same manner as Preparation Example 1. The physical properties are shown in Table 1.

[0123] Example 1 As component (A), 100 parts by mass of PO-1c1, as component (B1), 0.1 part by mass of B11-1 and 8 parts by mass of B12-1, and an organic solvent (methylcyclohexane / methyl ethyl ketone / toluene = 72 / 8 / 20 (v / v)) of 432 parts by mass (solid content concentration 20% by mass) were blended to obtain an adhesive composition. The blending amounts, adhesive strength, solder heat resistance, pot life properties, and electrical properties are shown in Table 1.

[0124] Examples 2 to 35, Comparative Examples 1 to 15 The blending amounts of components (A) to (C) were changed as shown in Tables 2 to 4, and Examples 2 to 35 and Comparative Examples 1 to 15 were carried out in the same manner as Example 1. The evaluation results of adhesive strength, solder heat resistance, electrical properties, and pot life are shown in Tables 2 to 4. The organic solvent (methylcyclohexane / methyl ethyl ketone / toluene = 72 / 8 / 20 (v / v)) was adjusted so that the solid content concentration was 20% by mass.

[0125]

Table 1

[0126]

Table 2

[0127]

Table 3

[0128]

Table 4

[0129] The epoxy resin (B1), isocyanate compound (B2), carbodiimide compound (B3), and oligophenylene ether (C) used in Tables 2 to 4 are as follows. <Epoxy resin (B1)> <Glycidylamine type epoxy resin (B11)> B11-1: N,N,N’,N’-tetraglycidyl-m-xylenediamine: TETRAD (registered trademark)-X (manufactured by Mitsubishi Gas Chemical Company, Inc.) <Glycidyl ether type epoxy resin (B12)> B12-1: Phenol novolak type epoxy resin: jER (registered trademark) 152 (manufactured by Mitsubishi Chemical Corporation) B12-2: o-Cresol novolak type epoxy resin: YDCN-700-3 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) <Alicyclic epoxy resin (B13)> B13-1: Dicyclopentadiene type epoxy resin: HP-7200H (manufactured by DIC Corporation, epoxy equivalent 278 g / eq) <Isocyanate compound (B2)> B21: Isocyanurate form of hexamethylene diisocyanate: Sumidur (registered trademark) N-3300 (manufactured by Bayer AG) B22: Biuret form of hexamethylene diisocyanate: Duranate (registered trademark) 24A-100 (manufactured by Asahi Kasei Chemicals Corporation) <Carbodiimide Compound (B3)> B31: Polyfunctional carbodiimide: Carbodilite (registered trademark) V-09 (manufactured by Nisshinbo Chemical Inc.) B32: Polyfunctional carbodiimide: Carbodilite (registered trademark) V-03 (manufactured by Nisshinbo Chemical Inc.) <Oligophenylene Ether (C)> C1: Styrene-modified oligophenylene ether: OPE-2St 2200 (a compound having the structure of general formula (4) with Mn 2000, manufactured by Mitsubishi Gas Chemical Company) C2: Oligophenylene ether: SA90 (a compound having the structure of general formula (3) with Mn 1800, manufactured by SABIC)

[0130] As is clear from Tables 2 to 4, in Examples 1 to 35, all of the adhesiveness, solder heat resistance, pot life, and dielectric properties are good. On the other hand, in Comparative Examples 1, 6, and 11, since the ratio of the carboxylic anhydride group (a1) / carboxylic acid group (a2) is low, the adhesiveness, solder heat resistance, and pot life between the liquid crystal polymer and the copper foil decreased. In Comparative Examples 2, 7, and 12, since the acid value of the acid-modified polyolefin (A) is high, the solder heat resistance and pot life decreased. In Comparative Examples 3, 8, and 13, since the acid value of the acid-modified polyolefin (A) is low, the adhesiveness and solder heat resistance between the liquid crystal polymer and the copper foil decreased. In Comparative Examples 4, 9, and 14, since the total amount of the carboxylic anhydride group (a1) and the carboxylic acid group (a2) is small, the solder heat resistance and pot life decreased. In Comparative Examples 5, 10, and 15, since none of the epoxy resin (B1), isocyanate compound (B2), and carbodiimide compound (B3) is contained, the solder heat resistance decreased.

Industrial Applicability

[0131] The adhesive composition of the present invention has excellent adhesiveness between not only polyimide but also a non-polar resin substrate such as a liquid crystal polymer and a metal substrate such as a copper foil. It further has excellent solder heat resistance and low dielectric properties, and also excellent pot life properties. The adhesive composition of the present invention can obtain an adhesive sheet and a laminate adhered using the same. Due to the above characteristics, it is useful in flexible printed wiring board applications, particularly in FPC applications where low dielectric properties (low dielectric constant, low dielectric tangent) in the high frequency region are required.

Claims

1. An adhesive composition for printed wiring boards, comprising an acid-modified polyolefin (A) satisfying the following (1) to (3), and further containing one or more selected from the group consisting of an epoxy resin (B1), an isocyanate compound (B2), and a carbodiimide compound (B3), wherein the adhesive composition for printed wiring boards is formulated to have a solid content concentration of 20% by mass using a mixed solvent consisting of methylcyclohexane, methyl ethyl ketone, and toluene (methylcyclohexane / methyl ethyl ketone / toluene = 72 / 8 / 20 (v / v)), when the solution viscosity is measured at 25 °C using a Brookfield viscometer (rotor No. 2, rotation speed 60 rpm), an adhesive composition for printed wiring boards, wherein, when the solution viscosity immediately after formulation is ηB0 and the solution viscosity after storage for 7 days is ηB, ηB / ηB0 is 0.5 or more and less than 3.

0. (1) The acid value is 5 to 50 mgKOH / g (2) The bonding ratio (molar ratio) of the carboxylic anhydride group represented by the formula (a1) to the carboxylic acid group represented by the formula (a2) is formula (a1) / formula (a2) = 100 / 0 to 91 / 9 (3) When the total acid components bonded to the acid-modified polyolefin (A) are 100 mol%, the total amount of formula (a1) and formula (a2) is 90 mol% or more 【Chemical 1】 [Chemical 2] [In formula (a1) and formula (a2), * represents a bond bonded to the acid-modified polyolefin (A).]

2. The adhesive composition for printed wiring boards according to claim 1, wherein the epoxy resin (B) contains a glycidylamine type epoxy resin (B1) and is further a mixture of one or more selected from the group consisting of a glycidyl ether type resin (B2) and an alicyclic epoxy resin (B3).

3. The adhesive composition for printed wiring boards according to claim 1, wherein the isocyanate compound (B2) is a polyfunctional isocyanate compound.

4. The adhesive composition for printed wiring boards according to claim 1, wherein the carbodiimide compound (B3) is a polyfunctional carbodiimide compound.

5. The adhesive composition for printed wiring boards according to any one of claims 1 to 4, further containing oligophenylene ether (C).

6. The adhesive composition for printed wiring boards according to any one of claims 1 to 5, further containing an organic solvent.

7. The adhesive composition for printed wiring boards according to any one of claims 1 to 6, wherein the relative permittivity (εc) at 1 GHz is 3.0 or less and the dielectric loss tangent (tanδ) is 0.02 or less.

8. A printed wiring board adhesive sheet containing the adhesive composition for printed wiring boards according to any one of claims 1 to 7.

9. A laminate for printed wiring boards containing the adhesive composition for printed wiring boards according to any one of claims 1 to 7.

10. A printed wiring board including the laminate for printed wiring boards according to claim 9 as a component.

11. A cover film including the printed wiring board according to claim 10 as a component.

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