Adhesive composition and laminate with an adhesive layer

Abstract

To provide an adhesive composition which is excellent in handleability, the adhesive composition being characterized in that the resulting cured film exhibits a sufficiently high dielectric constant, the cured film has flexibility, and is excellent in adhesion to an adherend, also to provide a laminate with an adhesive layer using the adhesive composition.SOLUTION: The adhesive composition includes a polyamide compound (A), an epoxy resin (B), and a titanate compound (C), wherein the polyamide compound (A) has an amine value of 10 mgKOH / g or less, the content of the titanate compound (C) is 60 to 610 parts by mass with respect to 100 parts by mass of the polyamide compound (A), and the cured product after curing reaction has a dielectric constant of 4.0 or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an adhesive composition and a laminate with an adhesive layer.

Background Art

[0002] Capacitive sensors are used in touch sensors, fingerprint authentication, inspection work, etc. For example, in fingerprint authentication, a semiconductor sensor element is provided on a substrate, and the difference in capacitance generated by the minute unevenness of the fingerprint and the distance from the sensor element is detected. Such capacitive sensors are generally protected by encapsulating the sensor element with a sealing material, but this sealing material causes a decrease in the sensitivity of the sensor. In order to prevent a decrease in the sensitivity of the sensor, it has been proposed to blend a high-dielectric inorganic filler into the sealing material to increase the dielectric constant of the sealing material (for example, Patent Document 1). Sealing materials for electronic components are known in various compositions, and among them, curable epoxy-based adhesives are widely used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an epoxy-based adhesive and a high-dielectric inorganic filler are combined, the resulting sealing material (cured film) can be made to exhibit a high dielectric constant and a high elastic modulus. However, as a result of investigations by the present inventors, these sealing materials are inferior in flexibility, and sufficient adhesive strength (peel strength) may not be exhibited. Furthermore, it has been found that the liquid viscosity of the adhesive before curing tends to increase, and problems with handleability are likely to occur.

[0005] The present invention aims to provide an adhesive composition that is excellent in handleability, the resulting cured film exhibits a sufficiently high dielectric constant, this cured film has flexibility, and also has excellent adhesion to an adherend. Further, the present invention aims to provide a laminate with an adhesive layer using this adhesive composition.

Means for Solving the Problems

[0006] The above problems of the present inventors are solved by the following means. [1] An adhesive composition comprising a polyamide compound (A), an epoxy resin (B), and a titanate compound (C), wherein the amine value of the polyamide compound (A) is 10 mgKOH / g or less, the content of the titanate compound (C) is 60 to 610 parts by mass with respect to 100 parts by mass of the content of the polyamide compound (A), and the dielectric constant of the cured product after the curing reaction is 4.0 or more. [2] The adhesive composition according to [1], wherein the dielectric constant of the titanate compound (C) is 100 or more. [3] The adhesive composition according to [1] or [2], wherein the titanate compound (C) is at least one of barium titanate, strontium titanate, and calcium titanate. [4] The adhesive composition according to any one of [1] to [3], containing a silane coupling agent. [5] The adhesive composition according to any one of [1] to [4], wherein the acid value of the polyamide compound (A) is 0.1 to 10 mgKOH / g. [6] The adhesive composition according to any one of [1] to [5], wherein the epoxy resin (B) has 3 or more epoxy groups in one molecule. [7] The adhesive composition according to any one of [1] to [6], wherein the epoxy resin (B) is a cresol novolak type epoxy resin. [8] The adhesive composition according to any one of [1] to [7], wherein the content of the epoxy resin (B) is 2 to 25 parts by mass with respect to 100 parts by mass of the content of the polyamide compound (A). [9] A laminate with an adhesive layer, comprising a base film and an adhesive layer composed of the adhesive composition according to any one of [1] to [8].

[0007] In the present invention, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. For example, when described as "A~B", the numerical range is "A or more and B or less".

[0008] In the present invention and in this specification, the term "adhesive layer" means a layer in a state before curing, a B-stage state (that is, a semi-cured state in which a part has started to cure and further curing proceeds by heating or the like), or a state after allowing the curing reaction to proceed to form a sufficiently crosslinked structure. Further, the terms "cured product" and "cured film" mean an object or a film in a state after allowing the adhesive composition to undergo a curing reaction to form a sufficiently crosslinked structure.

Advantages of the Invention

[0009] The adhesive composition of the present invention is excellent in handleability, the resulting cured film exhibits a sufficiently high dielectric constant, this cured film has flexibility, and also has excellent adhesion to an adherend. Further, in the laminate with an adhesive layer of the present invention, the cured film obtained by curing the adhesive layer exhibits a sufficiently high dielectric constant, this cured film has flexibility, and also has excellent adhesion to an adherend.

Embodiments for Carrying Out the Invention

[0010] Preferred embodiments of the adhesive composition of the present invention will be described below, but the present invention is not limited to the following embodiments except as defined in the present invention.

[0011] [Adhesive Composition] The adhesive composition of the present invention contains a polyamide compound (A), an epoxy resin (B), and a titanate compound (C). The amine value of the polyamide compound (A) is 1 to 10 mgKOH / g, the content of the titanate compound (C) is 60 to 610 parts by mass with respect to 100 parts by mass of the content of the polyamide compound (A), and the dielectric constant of the cured product after the curing reaction is 4.0 or more. Each component constituting the adhesive composition of the present invention will be described in order.

[0012] <Polyamide compound (A)> The adhesive composition of the present invention contains one or more polyamide compounds as the polyamide compound (A). There are no particular restrictions on the polyamide compound (A) used in the present invention, and polymers having a plurality of amide bonds in the polymer chain can be widely used. The polyamide compound (A) may have a polyether structure, a polyester structure, etc. in the polymer chain. The polyamide compound (A) can be synthesized, for example, by dehydration condensation reactions of various dicarboxylic acids and diamines, self-condensation of aminocarboxylic acids, ring-opening polymerization of intramolecular cyclic compounds of aminocarboxylic acids, and combinations of these reactions. Also, commercially available products can be widely used. As the polyamide compound (A) contained in the adhesive composition of the present invention, for example, the nylon resin described in JP-A-2010-31220 can be preferably used. When the adhesive composition contains a solvent, the polyamide compound (A) is preferably soluble in the solvent at room temperature (25°C). The polyamide compound may be a polyamide resin or a polyamide elastomer.

[0013] By containing a polyamide compound as a base resin, the adhesive composition of the present invention can effectively bring out the action of improving the dielectric constant by the blending of the titanate compound in the cured product. The reason for this is not clear, but it is considered that one of the reasons is that the titanate compound can be uniformly dispersed in a small particle size state with a high dielectric constant in the polyamide compound due to the polarity of the structure (amide bond) peculiar to the polyamide compound.

[0014] The polyamide compound (A) preferably contains a piperazine component as a diamine component. By containing the piperazine component, the adhesiveness to a flexible film such as a polyimide film can be enhanced. In the polyamide compound (A), the proportion (content) of the piperazine component in all the diamine components is preferably 20 mol% or more, and preferably 40 to 100 mol%.

[0015] The diamine components other than piperazine that can constitute the polyamide compound (A) are not particularly limited, and various diamine components can be appropriately incorporated according to the purpose. As an example, diamine components derived from ethylenediamine, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, p-diaminomethylcyclohexane, bis(p-aminocyclohexyl)methane, m-xylenediamine, isophoronediamine, etc. can be mentioned, but it is not limited thereto.

[0016] When the polyamide compound (A) contains a dicarboxylic acid component, this dicarboxylic acid component is not particularly limited and can be appropriately set according to the purpose. For example, dicarboxylic acid components derived from adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, dimer acid, isophthalic acid, terephthalic acid, sodium 5-sulfoisophthalate, etc. can be mentioned, but it is not limited thereto. From the viewpoint of solubility in a solvent, it is preferable to use all or part of dicarboxylic acids with relatively low crystallinity such as azelaic acid, undecanedioic acid, and dimer acid.

[0017] When the polyamide compound (A) contains an aminocarboxylic acid component, this aminocarboxylic acid component is not particularly limited and can be appropriately set according to the purpose. For example, aminocarboxylic acid components derived from 11-aminoundecanoic acid, 12-aminododecanoic acid, 4-aminomethylbenzoic acid, 4-aminomethylcyclohexanecarboxylic acid, etc. can be mentioned, but it is not limited thereto. Further, examples of the intramolecular cyclic compound of the above aminocarboxylic acid include β-lactam, ε-caprolactam, laurolactam, α-pyrrolidone, α-piperidone, etc., but it is not limited thereto.

[0018] In addition, a polyamide compound (A) obtained by introducing an N-alkoxymethyl group obtained by adding formalin and alcohol to a polyamide bond in a polyamide compound to form an alcohol-soluble nylon resin is also preferable as the polyamide compound (A). The introduction of the N-alkoxymethyl group contributes to a decrease in melting point, an increase in flexibility, and an improvement in solubility, and the introduction rate is determined according to the purpose.

[0019] Generally, when the amine value of the polyamide compound (A) is high and the acid value is low, the reaction between the amino group and the epoxy group of the epoxy resin (B) becomes faster, and good curability can be obtained by heat treatment for a short time. However, since the reaction proceeds even at room temperature, the reaction gradually proceeds from immediately after mixing, resulting in an increase in liquid viscosity or gelation, and problems are likely to occur in handleability. Therefore, in the present invention, the amine value of the polyamide compound (A) is controlled to be 10 mgKOH / g or less. The amine value is preferably 9 mgKOH / g or less, and more preferably 8 mgKOH / g or less. The lower limit of the amine value of the polyamide compound (A) is not particularly limited, and it is also preferably 0 mgKOH / g. Further, the acid value of the polyamide compound (A) is preferably 0.1 to 10 mgKOH / g, and more preferably 0.2 to 8 mgKOH / g. The "amine value" mentioned above means the number of milligrams of KOH equivalent to hydrochloric acid required to neutralize the amine present in 1 g of the polyamide compound (A). The "acid value" means the number of milligrams of KOH required to neutralize the acid present in 1 g of the polyamide compound (A). Details of the measurement methods for the amine value and the acid value are described in the section of [Examples] to be described later.

[0020] The adjustment of the molecular weight, amine value, etc. of the polyamide compound (A) can be carried out, for example, by adjusting the charging ratio of diamine and dicarboxylic acid, reaction time, and degree of reduced pressure when synthesizing the polyamide compound (A).

[0021] The content of the polyamide compound (A) is preferably 10 to 65% by mass, more preferably 15 to 60% by mass, and even more preferably 17 to 50% by mass in the total solid content of the adhesive composition (in the components excluding the solvent).

[0022] <Epoxy resin (B)> The adhesive composition of the present invention contains one or more kinds of epoxy resins as the epoxy resin (B). The epoxy resin (B) serves as a crosslinking agent for curing the polyamide compound (A). There is no particular limitation on the type of the epoxy resin (B), and the epoxy resins used in epoxy-based adhesives can be widely applied. Examples of the epoxy resin (B) include diglycidyl ethers of bisphenol A and their oligomers, diglycidyl esters of orthophthalic acid, diglycidyl esters of isophthalic acid, diglycidyl esters of terephthalic acid, diglycidyl esters of p-hydroxybenzoic acid, diglycidyl esters of tetrahydrophthalic acid, diglycidyl esters of succinic acid, diglycidyl esters of adipic acid, diglycidyl esters of sebacic acid, glycidyl esters such as triglycidyl ester of trimellitic acid, glycidyl ethers such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, polyglycidyl ethers of sorbitol, polyglycidyl ethers of polyglycerol, etc., but are not limited thereto. Further, novolak type epoxy resins such as phenol novolak type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin can be used, and among them, cresol novolak type epoxy resin is preferable.

[0023] From the viewpoint of enhancing the reactivity with the polyamide compound (A) and exhibiting high heat resistance, as the epoxy resin (B), it is preferable to use those having 3 or more epoxy groups in one molecule. For the epoxy resin (B), the number of epoxy groups in one molecule is preferably 3 to 10.

[0024] From the viewpoints of crosslinking point density and heat resistance, the content of the epoxy resin (B) contained in the adhesive composition of the present invention is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, still more preferably 5 to 20 parts by mass, and even more preferably 7 to 15 parts by mass with respect to 100 parts by mass of the polyamide compound (A).

[0025] The adhesive composition of the present invention is usually dissolved in a solvent and used as a solution-type adhesive. As the solvent, a solvent in which both the polyamide compound (A) and the epoxy resin (B) are dissolved is preferred. The polyamide compound (A) is generally soluble in alcohol solvents, and the epoxy resin (B) is generally dissolved in ketone solvents, ester solvents, aromatic solvents, and chlorine solvents. Therefore, the solvent is usually selected from combinations such as a mixed solvent of an alcohol solvent and a ketone solvent, a mixed solvent of an alcohol solvent and an ester solvent, and a mixed solvent of an alcohol solvent and an aromatic solvent.

[0026] Specific examples of the solvent include alcohol solvents (alcohol compounds) such as methanol, ethanol, i-propyl alcohol, n-propyl alcohol, i-butyl alcohol, n-butyl alcohol, benzyl alcohol, ethylene glycol methyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, and diacetone alcohol; ketone solvents (ketone compounds) such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, and cyclohexanone; aromatic solvents (aromatic compounds) such as toluene, xylene, ethylbenzene, and mesitylene; ester solvents (ester compounds) such as methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; and chlorine solvents (chlorine compounds) such as chloroform, carbon tetrachloride, dichloromethane, and trichloroethylene. In addition, in order to improve the solubility of the polyamide compound (A), those obtained by adding water, phenol, formic acid, acetic acid, etc. can also be used. Among these solvents, a mixed solvent in which one or more alcohol solvents and other solvents are used in combination is preferred as the solvent of the adhesive composition of the present invention. Examples of such mixed solvents include mixed solvents such as methanol / toluene mixed solvent, i-propyl alcohol / toluene mixed solvent, and i-isopropyl alcohol / dichloromethane mixed solvent. From the viewpoint of the solubility of the polyamide compound (A) and the epoxy resin (B), the proportion of the alcohol solvent in the total solvent amount of the adhesive composition of the present invention is preferably 30 to 80% by mass.

[0027] <Titanate compound (C)> The adhesive composition of the present invention contains, as the titanate compound (C), one or more kinds of titanate compounds. The titanate compound (C) is an inorganic filler contained in the form of particles in the adhesive composition of the present invention. The titanate compound is preferably a composite oxide of titanic acid and an alkaline earth metal. For example, barium titanate, strontium titanate, calcium titanate, magnesium titanate, etc. can be mentioned.

[0028] In the adhesive composition of the present invention, the content of the titanate compound (C) is 60 to 610 parts by mass, preferably 70 to 610 parts by mass, more preferably 100 to 610 parts by mass, still more preferably 150 to 600 parts by mass, and still more preferably 200 to 500 parts by mass, based on 100 parts by mass of the content of the polyamide compound (A) from the viewpoints of high dielectric constant and good adhesiveness.

[0029] The dielectric constant ε (measurement frequency: 1 MHz) of the titanate compound (C) is preferably 100 or more, more preferably 120 or more, and still more preferably 150 or more. The upper limit value of the dielectric constant ε of the titanate compound (C) is not particularly limited, but is usually practically 15000 or less. The dielectric constant ε of the titanate compound (C) can be determined by the method described in the section of [Examples] described later.

[0030] The adhesive composition according to the present invention contains a combination of a polyamide compound (A) and an epoxy resin (B), and further contains a combination of a titanate compound (C), so that an increase in the liquid viscosity of the adhesive composition is suppressed and the handleability is excellent. The adhesive layer formed using this composition exhibits a strong adhesive force to the adherend by a curing reaction, and can also achieve a higher dielectric constant. Furthermore, the flexibility of the sealing material can be ensured, and it can also be applied to flexible devices.

[0031] <Properties of the adhesive composition> The dielectric constant of the adhesive composition according to the present invention is 4.0 or more, preferably 4.5 or more, more preferably 5.0 or more, still more preferably 8.0 or more, and even more preferably 10.0 or more. The upper limit value of the dielectric constant is not particularly limited, but is usually 100.0 or less. The dielectric constant of the cured product of the adhesive composition can be determined by the method described in the section of [Examples] described later.

[0032] The peel strength of the cured product of the adhesive composition according to the present invention is preferably 10.0 N / cm or more, and more preferably 11.0 N / cm or more. The upper limit value of the peel strength is not particularly limited, but is usually 50.0 N / cm or less. The peel strength can be determined by the method described in the section of [Examples] described later.

[0033] The liquid viscosity of the adhesive composition according to the present invention is preferably 100 to 30000 mPa·s, more preferably 100 to 25000 mPa·s, still more preferably 150 to 25000 mPa·s, and even more preferably 200 to 25000 mPa·s. The liquid viscosity can be determined by the method described in the section of [Examples] described later.

[0034] The elastic modulus of the cured product of the adhesive composition according to the present invention is preferably 0.1 to 5.2 GPa, more preferably 0.8 to 4.0 GPa, still more preferably 1.2 to 3.7 GPa, also still more preferably 1.3 to 3.0 GPa, also still more preferably 1.9 to 2.0 GPa, and also still more preferably 2.4 to 2.5 GPa. The elastic modulus (tensile test) can be determined by the method described in the section of [Examples] described later.

[0035] <Other components> In addition to the polyamide compound (A), epoxy resin (B), and titanate compound (C), additives may be incorporated into the adhesive composition of the present invention for various purposes such as improving adhesion and solution properties. Examples include coupling agents, antioxidants, ultraviolet absorbers, flame retardants, fillers different from the titanate compound (C), leveling agents, defoaming agents, thickeners, dyes, and the like. Such additives can be added when dissolving the raw materials in a solvent or after dissolution.

[0036] Examples of coupling agents include silane-based coupling agents (silane coupling agents) such as vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyltriethoxysilane; titanate-based coupling agents (titanate coupling agents); aluminate-based coupling agents (aluminate coupling agents); zirconium-based coupling agents (zirconium coupling agents).

[0037] The content of the coupling agent is preferably 0.5 to 3.0 parts by mass, more preferably 1.0 to 2.0 parts by mass, based on 100 parts by mass of the content of the polyamide compound (A).

[0038] Examples of antioxidants include phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol, n-octadecyl 3-(3’,5’-di-t-butyl-4’-hydroxyphenyl)propionate, and tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane; sulfur antioxidants such as dilauryl 3,3’-thiodipropionate and dimyristyl 3,3’-dithiopropionate; and phosphorus antioxidants such as trisnonylphenyl phosphite and tris(2,4-di-t-butylphenyl) phosphite.

[0039] Examples of ultraviolet absorbers include benzotriazole ultraviolet absorbers such as 2-(2’-hydroxy-5’-methylphenyl)benzotriazole and 2-[(2’-hydroxy-3’,5’-bis(α,α-dimethylbenzyl)phenyl]benzotriazole; benzophenone ultraviolet absorbers such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy-4-n-octylbenzophenone; salicylate ultraviolet absorbers such as phenyl salicylate; cyanoacrylate ultraviolet absorbers such as ethyl 2-cyano-3,3-diphenylacrylate; oxalic anilide ultraviolet absorbers such as 2-ethoxy-2’-ethyloxalic acid bisanilide; and hindered amine ultraviolet absorbers such as bis-[2,2,6,6-tetramethyl-4-piperidinyl] sebacate and bis-[N-methyl-2,2,6,6-tetramethyl-4-piperidinyl] sebacate.

[0040] Examples of flame retardants include brominated flame retardants such as tetrabromobisphenol A, hexabromobenzene, decabromodiphenyl ether, hexabromocyclododecane, bis(pentabromophenyl)ethane, and bis(tetrabromophthalimide)ethane; aromatic phosphate ester flame retardants such as triphenyl phosphate, 2-ethylhexyl diphenyl phosphate, and cresyl diphenyl phosphate; aromatic condensed phosphate esters such as 1,3-phenylene bis(diphenyl phosphate), 1,3-phenylene bis(dixylenyl)phosphate, and bisphenol A bis(diphenyl phosphate); halogen-containing phosphate ester flame retardants such as tris(dichloropropyl)phosphate; red phosphorus-based flame retardants such as red phosphorus; inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide, and antimony trioxide; silicone-based flame retardants; and boron-based flame retardants.

[0041] Examples of fillers include calcium carbonate, titanium oxide, zinc oxide, talc, calcium carbonate, carbon black, silica, copper powder, aluminum powder, silver powder, and the like.

[0042] In the present invention, the adhesive composition containing the polyamide compound (A), epoxy resin (B), and titanate compound (C) is usually preferably dissolved in the above solvent together with any of the above additives and used as a solution-type adhesive. When used as a solution-type adhesive, the resin concentration of the adhesive composition (the total of the concentrations of the polyamide compound (A) and epoxy resin (B) (mass%)) is preferably 10 to 35 mass%, more preferably 15 to 30 mass%.

[0043] [Laminated body with an adhesive layer] The laminated body with an adhesive layer according to the present invention includes an adhesive layer made of the above adhesive composition and a base film in contact with at least one surface of the adhesive layer.

[0044] One aspect of the laminated body with an adhesive layer according to the present invention is a coverlay film. The coverlay film has an adhesive layer formed on at least one surface of the base film.

[0045] As the base film in the case where the laminate with an adhesive layer is a coverlay film, examples thereof include a polyimide film, a polyetheretherketone film, a polyphenylene sulfide film, an aramid film, a polyethylene naphthalate film, and a liquid crystal polymer film. Among these, from the viewpoints of adhesiveness and electrical properties, a polyimide film, a polyethylene naphthalate film, and a liquid crystal polymer film are preferable.

[0046] Such base films are commercially available. For polyimide films, "Kapton (registered trademark)" manufactured by Toray DuPont Co., Ltd., "ZENOMAX (registered trademark)" manufactured by Toyobo Co., Ltd., "UPILLEX (registered trademark)-S" manufactured by Ube Industries, Ltd., "Apical (registered trademark)" manufactured by Kaneka Corporation, etc. can be used. Also, for polyethylene naphthalate films, "Teonex (registered trademark)" manufactured by Teijin DuPont Films Co., Ltd., etc. can be used. Further, for liquid crystal polymer films, "Vectra (registered trademark)" manufactured by Kuraray Co., Ltd., "Biax (registered trademark)" manufactured by Primetec Co., Ltd., etc. can be used. The base film can also be used by forming a film of the corresponding resin to a desired thickness.

[0047] As a method for manufacturing a coverlay film, for example, a resin varnish containing the above adhesive composition and a solvent is applied to the surface of a base film such as a polyimide film to form a resin varnish layer, and then the solvent is removed from this resin varnish layer, whereby a coverlay film having an adhesive layer formed thereon can be manufactured. The drying temperature when removing the above solvent is preferably 40 to 250°C, and more preferably 70 to 170°C. Drying is performed by passing the laminate coated with the adhesive composition through a furnace where hot air drying, far-infrared heating, high-frequency induction heating, etc. are performed. In addition, if necessary, a release film may be laminated on the surface of the adhesive layer for storage or the like. As the release film, ordinary ones such as polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release-treated paper, polyolefin resin-coated paper, polymethylpentene (TPX) film, and fluororesin film are used.

[0048] Another aspect of the laminate with an adhesive layer is a bonding sheet. The bonding sheet is also one in which the adhesive layer is formed on the surface of the base film, but a release film is used as the base film. Further, the bonding sheet may be in a form having an adhesive layer between two release films. When using the bonding sheet, the release film is peeled off and used. As the release film, the same ones as those described above can be used.

[0049] Such release films are also commercially available, and "Lumirror (registered trademark)" manufactured by Toray Film Processing Co., Ltd., "Toyobo Ester (registered trademark) Film" manufactured by Toyobo Co., Ltd., "Afflex (registered trademark)" manufactured by Asahi Glass Co., Ltd., "Opulan (registered trademark)" manufactured by Mitsui Chemicals Toagosei Co., Ltd., etc. can be used.

[0050] As a method for manufacturing the bonding sheet, for example, there is a method of applying a resin varnish containing the adhesive composition and a solvent on the surface of the release film and drying it in the same manner as in the case of the coverlay film.

[0051] The thickness of the base film is preferably 5 to 100 μm, more preferably 5 to 50 μm, and even more preferably 5 to 30 μm in order to make the laminate with an adhesive layer thinner.

[0052] The thickness of the adhesive layer is preferably 5 to 100 μm, more preferably 10 to 70 μm, and even more preferably 10 to 50 μm. The thicknesses of the above-mentioned base film and the adhesive layer are selected according to the application. However, in order to improve the electrical properties, the base film tends to be thinner. Generally, when the thickness of the base film is thin and the thickness of the adhesive layer is thick, the laminated body with the adhesive layer is likely to warp, and the workability deteriorates. However, in the laminated body with the adhesive layer of the present invention, even when the thickness of the base film is thin and the thickness of the adhesive layer is thick, almost no warping of the laminated body occurs. In the laminated body with the adhesive layer of the present invention, the ratio (D1 / D2) of the thickness (D1) of the adhesive layer to the thickness (D2) of the base film is preferably 1 to 10, and more preferably 1 to 5 or less. Further, it is preferable that the thickness of the adhesive layer is thicker than the thickness of the base film.

[0053] As another aspect of the laminated body with the adhesive layer, a copper-clad laminate can be mentioned. A copper-clad laminate is a laminate in which a polyimide film as a base film and a copper foil are bonded together using the above-mentioned adhesive layer. That is, a copper-clad laminate is a laminate composed of a base film, an adhesive layer, and a copper foil in this order. In the copper-clad laminate, the adhesive layer and the copper foil may be formed on both sides of the base film. That is, the copper-clad laminate may be a laminate including an adhesive layer and a copper foil sequentially on one side and the other side of the base film. Since the adhesive composition of the present invention is excellent in adhesiveness to an article containing copper, the copper-clad laminate is excellent in stability as an integrated product. Note that the adhesive layer contained in the copper-clad laminate of the present invention may be composed of a cured product or an uncured product. The thickness of the adhesive layer in the copper-clad laminate is preferably 5 to 45 μm, and more preferably 10 to 35 μm.

[0054] As a method for manufacturing a copper-clad laminate, for example, a method in which the adhesive layer of the above-mentioned coverlay film and the copper foil are brought into surface contact, heat lamination is performed at 80 to 150 ° C, and the adhesive layer is further cured by post-cure can be applied. The conditions for post-cure can be, for example, 100 to 200 ° C, 30 minutes to 4 hours. Note that the copper foil is not particularly limited, and an electrolytic copper foil, a rolled copper foil, or the like can be used.

[0055] [Article with an adhesive layer] The article with an adhesive layer according to the present invention is an article provided with an adhesive layer composed of the above adhesive composition. A preferred embodiment in the present invention is an electromagnetic shielding material provided with an adhesive layer. Thereby, it is possible to prevent malfunction of electronic devices due to electromagnetic wave noise, leakage of confidential information due to interception of communication radio waves, and the like. As a method for manufacturing the electromagnetic shielding material of the present invention, for example, a method of joining a high-dielectric bonding sheet provided with an adhesive layer and a shielding material can be applied. The thickness of the adhesive layer in the electromagnetic shielding material is preferably 5 to 100 μm, more preferably 10 to 70 μm.

[0056] Another aspect of the article with an adhesive layer includes an antenna substrate, a capacitor, a capacitance type sensor, a piezoelectric film speaker, etc., provided with an adhesive layer composed of the above adhesive composition.

Examples

[0057] The present invention will be described more specifically based on examples, but the present invention is not limited thereto. In the following, "parts" and "%" are based on mass unless otherwise specified.

[0058] [Preparation of adhesive composition] <Example 1> 100 parts by mass of polyamide compound a (acid value: 7 mgKOH / g, amine value: 3 mgKOH / g), 10 parts by mass of o-cresol novolak type epoxy resin (trade name: EPICLON N-665, manufactured by DIC Corporation), epoxy silane coupling agent (trade name: SH-6040, manufactured by DuPont-Toray Specialty Materials Co., Ltd.) 1.11 parts by mass, barium titanate (trade name: BT-05, manufactured by Sakai Chemical Industry Co., Ltd., dielectric constant: 4590) 67.1 parts by mass, and 394 parts by mass of a mixed solvent of methanol / toluene = 1 / 1 (mass ratio) were added and mixed to prepare an adhesive solution (adhesive composition).

[0059] <Example 2> An adhesive solution was prepared in the same manner as in Example 1, except that the amount of barium titanate charged was changed to 151 parts by mass.

[0060] <Example 3> An adhesive solution was prepared in the same manner as in Example 1, except that the amount of barium titanate charged was changed to 259 parts by mass.

[0061] <Example 4> An adhesive solution was prepared in the same manner as in Example 1, except that the amount of barium titanate charged was changed to 404 parts by mass.

[0062] <Example 5> An adhesive solution was prepared in the same manner as in Example 1, except that the amount of barium titanate charged was changed to 606 parts by mass.

[0063] <Example 6> An adhesive solution was prepared in the same manner as in Example 1, except that polyamide compound a was changed to polyamide compound b (acid value: 1 mg KOH / g, amine value: 4.5 mg KOH / g) and the amount of barium titanate charged was changed to 404 parts by mass.

[0064] <Example 7> An adhesive solution was prepared in the same manner as in Example 1, except that polyamide compound a was changed to polyamide compound c (acid value: 1 mg KOH / g, amine value: 4.5 mg KOH / g) and the amount of barium titanate charged was changed to 404 parts by mass.

[0065] <Example 8> An adhesive solution was prepared in the same manner as in Example 1, except that 67.1 parts by mass of barium titanate was changed to 322 parts by mass of strontium titanate (trade name: ST-A, manufactured by Fuji Titanium Industry Co., Ltd., dielectric constant: 300).

[0066] <Example 9> An adhesive solution was prepared in the same manner as in Example 1, except that 67.1 parts by mass of barium titanate was changed to 276 parts by mass of calcium titanate (trade name: CT-3, manufactured by Kyoritsu Materials Co., Ltd., dielectric constant: 180).

[0067] <Example 10> An adhesive solution was prepared in the same manner as in Example 4, except that the amount of o-cresol novolac type epoxy resin charged was changed to 2 parts by mass.

[0068] <Example 11> An adhesive solution was prepared in the same manner as in Example 4, except that the amount of o-cresol novolac type epoxy resin charged was changed to 25 parts by mass.

[0069] <Comparative Example 1> 100 parts by mass of an epoxy resin (trade name: Epicoat 828, manufactured by Mitsubishi Chemical Corporation), 25 parts by mass of diethylene glycol diglycidyl ether (trade name: SR-2EGS, manufactured by Sakamoto Pharmaceutical Co., Ltd.), 48.5 parts by mass of a modified aliphatic polyamine (trade name: Fujicure FXJ-8074-D, manufactured by T&K Toka Co., Ltd.), 1.5 parts by mass of aminopropyltriethoxysilane (trade name: A-1100, manufactured by Nisshio Sangyo Co., Ltd.), and 97.2 parts by mass of barium titanate (trade name: BT-05, manufactured by Sakai Chemical Industry Co., Ltd.) were mixed to prepare an adhesive composition.

[0070] <Comparative Example 2> 100 parts by mass of an epoxy resin (trade name: Epicoat 807, manufactured by Mitsubishi Chemical Corporation), 19 parts by mass of m-phenylenediamine (trade name: Epikure Z, manufactured by Mitsubishi Chemical Corporation), 1.84 parts by mass of an epoxy silane coupling agent (trade name: KBM-402, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.79 parts by mass of a titanate coupling agent (trade name: KR-46B, manufactured by Ajinomoto Fine-Techno Co., Inc.), and 426 parts by mass of barium titanate (trade name: BT-05, manufactured by Sakai Chemical Industry Co., Ltd.) were mixed to prepare an adhesive composition.

[0071] <Comparative Example 3> 100 parts by mass of an acid-modified polyolefin resin (trade name: Auroren 500S, manufactured by Nippon Paper Industries Co., Ltd.), 0.1 part by mass of dioctyltin dilaurate (manufactured by Kishida Chemical Co., Ltd.), 10 parts by mass of hexamethylene diisocyanate (trade name: Duranate TKA-100, manufactured by Asahi Kasei Corporation), and 78.2 parts by mass of barium titanate (trade name: BT-05, manufactured by Sakai Chemical Industry Co., Ltd.) were put into 567 parts by mass of a mixed solvent of methylcyclohexane / methyl ethyl ketone = 3.7 / 1 (mass ratio) and mixed to prepare an adhesive solution (adhesive composition).

[0072] <Comparative Example 4> 100 parts by mass of an acrylic polymer (trade name: UH-2041, manufactured by Toagosei Co., Ltd.), 0.1 part by mass of dioctyltin dilaurate (manufactured by Kishida Chemical Co., Ltd.), 102 parts by mass of hexamethylene diisocyanate (trade name: Duranate AE-700-100, manufactured by Asahi Kasei Corporation), and 66.7 parts by mass of barium titanate (trade name: BT-05, manufactured by Sakai Chemical Industry Co., Ltd.) were mixed to prepare an adhesive composition.

[0073] <Comparative Example 5> An adhesive solution was prepared in the same manner as in Example 1, except that 121 parts by mass of silica (trade name: Excellica SE-1, manufactured by Tokuyama Corporation) was added instead of 67.1 parts by mass of barium titanate.

[0074] <Comparative Example 6> An adhesive solution was prepared in the same manner as in Example 1, except that 154 parts by mass of boron nitride (trade name: PCTP-2, manufactured by Saint-Gobain Corporation) was added instead of 67.1 parts by mass of barium titanate.

[0075] <Comparative Example 7> An adhesive solution was prepared in the same manner as in Example 1, except that the amount of barium titanate added was changed to 35 parts by mass.

[0076] <Comparative Example 8> An adhesive solution was prepared in the same manner as in Example 1, except that the amount of barium titanate added was changed to 908 parts by mass.

[0077] <Comparative Example 9> An adhesive solution was prepared in the same manner as in Example 1, except that barium titanate was not added.

[0078] [Evaluation Method] <Method for Measuring Amine Value of Polyamide Compound> The polyamide compound was dissolved in a mixed solution of 20 ml of 1-butanol and 20 ml of toluene, and a burette "APB-510-01B" manufactured by the same company was connected to an automatic titrator "AT-510" manufactured by Kyoto Electronics Industry Co., Ltd. as a burette. Potentiometric titration was performed using a 0.1 mol / L 2-propanolic hydrochloric acid solution as a titrant, and the number of mg of KOH equivalent to hydrochloric acid per 1 g of the polyamide compound was calculated.

[0079] <Method for Measuring Acid Value of Polyamide Compound> 1 g of the polyamide compound was dissolved in 40 ml of benzyl alcohol, and a burette "APB-510-20B" manufactured by the same company was connected to an automatic titrator "AT-510" manufactured by Kyoto Electronics Industry Co., Ltd. as a burette. Potentiometric titration was performed using a 0.01 mol / L benzyl alcoholic KOH solution as a titrant, and the number of mg of KOH per 1 g of the polyamide compound was calculated.

[0080] <Method for Measuring Dielectric Constant> (Cured Products of Adhesive Compositions Prepared in Examples 1 to 11 and Comparative Examples 5 to 9) A release polyethylene terephthalate film with a thickness of 38 μm was prepared, and the adhesive composition was roll-coated on one surface thereof. Next, the film with the coating film was left standing in an oven and dried at 90°C for 3 minutes to form a film (adhesive layer) with a thickness of 50 μm. Next, this film was left standing in an oven and heat-treated at 150°C for 30 minutes. By this heat treatment, the curing reaction (crosslinking reaction) of the film proceeds sufficiently. Thereafter, the release film was peeled off to prepare a test piece (50 × 50 mm). The dielectric constant (ε) was measured at a temperature of 23°C and a frequency of 10 GHz by the split post dielectric resonator method (SPDR method) using a network analyzer 85071E-300 (manufactured by Agilent Technologies).

[0081] (Cured products of the adhesive compositions prepared in Comparative Examples 1 and 2) A release polyethylene terephthalate film with a thickness of 38 μm was prepared, and the adhesive composition was roll-coated on one surface thereof. Next, the film with the coating film was left standing in an oven and dried at 90°C for 3 minutes to form a film (adhesive layer) with a thickness of 50 μm. Next, this film was left standing in an oven and heat-treated at 130°C for 5 minutes. By this heat treatment, the curing reaction (crosslinking reaction) of the film proceeds sufficiently. Thereafter, the release film was peeled off to prepare test pieces (50 × 50 mm). The dielectric constant (ε) was measured under the conditions of a temperature of 23°C and a frequency of 10 GHz by the split post dielectric resonator method (SPDR method) using a network analyzer 85071E-300 (manufactured by Agilent Technologies).

[0082] (Cured product of the adhesive composition prepared in Comparative Example 3) A release polyethylene terephthalate film with a thickness of 38 μm was prepared, and the adhesive composition was roll-coated on one surface thereof. Next, the film with the coating film was left standing in an oven and dried at 90°C for 3 minutes to form a film (adhesive layer) with a thickness of 50 μm. Next, this film was left standing in an oven and cured at 40°C for 1 day. By this curing, the curing reaction (crosslinking reaction) of the film proceeds sufficiently. Thereafter, the release film was peeled off to prepare test pieces (50 × 50 mm). The dielectric constant (ε) was measured under the conditions of a temperature of 23°C and a frequency of 10 GHz by the split post dielectric resonator method (SPDR method) using a network analyzer 85071E-300 (manufactured by Agilent Technologies).

[0083] (Cured product of the adhesive composition prepared in Comparative Example 4) A release polyethylene terephthalate film with a thickness of 38 μm was prepared, and an adhesive composition was roll-coated on one of its surfaces. Then, the film with the coating was left standing in an oven and dried at 90 °C for 3 minutes to form a film (adhesive layer) with a thickness of 50 μm. Next, this film was left standing in the oven and heat-treated at 80 °C for 1 hour. By this heat treatment, the curing reaction (crosslinking reaction) of the film proceeded sufficiently. Thereafter, the release film was peeled off to prepare test pieces (50 × 50 mm). The dielectric constant (ε) was measured using a network analyzer 85071E-300 (manufactured by Agilent Technologies) by the split post dielectric resonator method (SPDR method) under the conditions of a temperature of 23 °C and a frequency of 10 GHz.

[0084] (Titanate compound (C)) After polishing a barium titanate sheet made of titanate compound (C) to a thickness of 0.4 mm, it was cut into a size of 1.5 mm × 4 mm, silver electrodes were provided on both sides, and the temperature was oscillated in the range from room temperature (25 °C) to 500 °C at a frequency of 1 MHz, and the dielectric constant was measured electrically.

[0085] <Measurement method of peel strength> (Cured products of the adhesive compositions prepared in Examples 1 to 11 and Comparative Examples 5 to 9) A rolled copper foil with a thickness of 35 μm was prepared, and an adhesive composition was roll-coated on its surface. Subsequently, the film with the coating was left standing in an oven and dried at 90 °C for 3 minutes to form a film (adhesive layer) with a thickness of 50 μm, thereby obtaining a copper foil with an adhesive layer. Thereafter, a copper-clad laminate with a polyimide layer having a thickness of 57 μm was superposed so that the polyimide layer side was in surface contact with the surface of the adhesive layer of the copper foil with an adhesive layer, and laminated under the conditions of a temperature of 120 °C and a pressure of 0.5 MPa. Next, this laminate (copper-clad laminate with polyimide / adhesive layer / copper foil) was heat-pressed at a temperature of 150 °C and a pressure of 3 MPa for 30 minutes to obtain a substrate for evaluating peel adhesion strength. This evaluation substrate was cut to prepare an adhesive test piece of a predetermined size. In order to evaluate the adhesiveness, in accordance with JIS C 6481:2015, the 90° peel adhesion strength (N / cm) when peeling the rolled copper foil from the adhesive test piece was measured under the conditions of a temperature of 23 °C and a tensile speed of 50 mm / min. The width of the adhesive test piece at the time of measurement was set to 10 mm.

[0086] (Cured products of the adhesive compositions prepared in Comparative Examples 1 and 2) A rolled copper foil with a thickness of 35 μm was prepared, and an adhesive composition was roll-coated on its surface. Subsequently, the film with the coating was left standing in an oven and dried at 90 °C for 3 minutes to form a film (adhesive layer) with a thickness of 50 μm, thereby obtaining a copper foil with an adhesive layer. Thereafter, a copper-clad laminate with a polyimide layer having a thickness of 57 μm was superposed so that the polyimide layer side was in surface contact with the surface of the adhesive layer of the copper foil with an adhesive layer, and laminated under the conditions of a temperature of 120 °C and a pressure of 0.5 MPa. Next, this laminate (copper-clad laminate with polyimide / adhesive layer / copper foil) was heat-pressed at a temperature of 130 °C and a pressure of 3 MPa for 3 minutes to obtain a substrate for evaluating peel adhesion strength. This evaluation substrate was cut to prepare an adhesive test piece of a predetermined size. In order to evaluate the adhesiveness, in accordance with JIS C 6481:2015, the 90° peel adhesion strength (N / cm) when peeling the rolled copper foil from the adhesive test piece was measured under the conditions of a temperature of 23 °C and a tensile speed of 50 mm / min. The width of the adhesive test piece at the time of measurement was set to 10 mm.

[0087] (Cured product of the adhesive composition prepared in Comparative Example 3) A rolled copper foil with a thickness of 35 μm was prepared, and an adhesive composition was roll-coated on its surface. Next, the film with the coating film was left standing in an oven and dried at 90 °C for 3 minutes to form a film (adhesive layer) with a thickness of 50 μm, and a copper foil with an adhesive layer was obtained. Then, a copper-clad laminate with a polyimide layer having a thickness of 57 μm was superposed so that the polyimide layer side was in surface contact with the surface of the adhesive layer of the copper foil with the adhesive layer, and lamination was performed under the conditions of a temperature of 80 °C, a pressure of 0.4 MPa, and a speed of 0.5 m / min. Next, this film was left standing in an oven and cured at 40 °C for 1 day to obtain a substrate for evaluating peel adhesion strength. This evaluation substrate was cut to produce an adhesive test piece of a predetermined size. To evaluate the adhesiveness, in accordance with JIS C 6481:2015, the 90° peel adhesion strength (N / cm) when peeling the rolled copper foil from the adhesive test piece was measured under the conditions of a temperature of 23 °C and a tensile speed of 50 mm / min. The width of the adhesive test piece at the time of measurement was set to 10 mm.

[0088] (Cured product of the adhesive composition prepared in Comparative Example 4) A rolled copper foil with a thickness of 35 μm was prepared, and an adhesive composition was roll-coated on its surface. Next, the film with the coating film was left standing in an oven and dried at 90 °C for 3 minutes to form a film (adhesive layer) with a thickness of 50 μm, and a copper foil with an adhesive layer was obtained. Then, a copper-clad laminate with a polyimide layer having a thickness of 57 μm was superposed so that the polyimide layer side was in surface contact with the surface of the adhesive layer of the copper foil with the adhesive layer, and lamination was performed under the conditions of a temperature of 80 °C, a pressure of 0.4 MPa, and a speed of 0.5 m / min. Next, this film was left standing in an oven and heat-treated at 80 °C for 1 hour to obtain a substrate for evaluating peel adhesion strength. This evaluation substrate was cut to produce an adhesive test piece of a predetermined size. To evaluate the adhesiveness, in accordance with JIS C 6481:2015, the 90° peel adhesion strength (N / cm) when peeling the rolled copper foil from the adhesive test piece was measured under the conditions of a temperature of 23 °C and a tensile speed of 50 mm / min. The width of the adhesive test piece at the time of measurement was set to 10 mm.

[0089] <Measurement method of coatability (liquid viscosity)> The liquid viscosity of the adhesive composition was measured using a TVE-20H viscometer (salt water / plate method, manufactured by Toki Sangyo Co., Ltd.), which is an E-type viscometer (cone and plate viscometer), under the following conditions. If the liquid viscosity was 30,000 mPa·s or less, it was judged that the coating property was good. -Measurement conditions- Cone shape: Angle 3°×R9.7’, radius 20 mm Temperature: 25°C ± 0.5°C

[0090] <Measurement method of flexibility> (Tensile test) Test pieces were prepared in the same manner as the measurement of the above electrical properties (dielectric constant and dielectric loss tangent), and a tensile test was conducted at 23°C using "Autograph AG-Xplus" manufactured by Shimadzu Corporation, with a distance between jigs of 40 mm, a distance between gauge marks of 20 mm, a tensile speed of 5 mm / min. The strain was measured in real time using a camera. The strain from the origin to the yield point was divided into 10 equal parts, and the slope of the tangent line in each section was calculated by the least squares method to calculate the tensile modulus. (Bending test) For the test pieces prepared in the same manner as the above tensile test, based on the flexural resistance test (cylindrical mandrel method) conforming to JIS K5600-5-1:2018, the test pieces were wound around an iron rod with a diameter of 2 mm, and whether cracks occurred was visually observed. Those without cracks were evaluated as "○", and those with cracks were evaluated as "×".

[0091] The compositions of the adhesive compositions according to Examples 1 to 11 and Comparative Examples 1 to 9 are shown in Tables 1 and 2, and the results of the above various measurements for the adhesive compositions according to Examples 1 to 11 and Comparative Examples 1 to 9 are shown in Table 3.

[0092]

Table 1

[0093] (Note to Table 1) ·Values in the table: parts by mass ·The values in parentheses in the filler column are the volume % in the solid content

[0094] [Table 2]

[0095] (Note to Table 2) Values in the table: parts by mass The values in parentheses in the filler column are volume % in solids "Dioctyltin dilaurate" was omitted from Table 2

[0096] [Table 3]

[0097] (Note to Table 3) The "-" in Comparative Example 1 means that the adhesive composition solidified 15 minutes after coating, and the coatability (liquid viscosity) could not be measured

[0098] In Comparative Example 5 where no titanate compound was included as the filler and silica particles were compounded, the dielectric constant of the cured product could not be increased to the desired level. The same applies to Comparative Example 6 where boron nitride was compounded as the filler and Comparative Example 9 where no filler was compounded Also, even when a titanate compound is compounded as the filler, if the amount is small, the dielectric constant of the cured product still cannot be increased to the desired level (Comparative Example 7). Conversely, if the compounding amount of the titanate compound is too large, the liquid viscosity increases, resulting in poor handling properties and also poor peel strength of the cured product (Comparative Example 8) Also, even if a desired amount of titanate compound is compounded as the filler, when the base resin (matrix resin) does not contain a polyamide compound and the base resin is only an epoxy resin and reacted using a curing agent, the curing reaction proceeds too quickly, resulting in extremely poor handling properties, and the resulting cured product is hard and poor in flexibility (Comparative Examples 1 and 2) Further, when the base resin is composed of a polyolefin resin or an acrylic polymer having a reactive group without using an epoxy resin and these are reacted with a polyisocyanate to cause a curing reaction, even if a titanic acid compound is blended, the dielectric constant cannot be increased to a desired level, and the peel strength is also inferior (Comparative Examples 3 and 4). On the other hand, all of the adhesive compositions defined in the present invention are excellent in handleability, and the obtained cured product sufficiently exhibits the high dielectric characteristics of the titanic acid compound and shows a high dielectric constant. This cured product also has flexibility and excellent adhesive strength to an adherend (Examples 1 to 11).

Claims

1. A polyamide compound (A), an epoxy resin (B), and a titanate compound (C), wherein the amine value of the polyamide compound (A) is 10 mgKOH / g or less, the content of the titanate compound (C) is 60 to 610 parts by mass with respect to 100 parts by mass of the content of the polyamide compound (A), and the dielectric constant of the cured product after the curing reaction is 4.0 or more, an adhesive composition.

2. The adhesive composition according to claim 1, wherein the dielectric constant of the titanate compound (C) is 100 or more.

3. The adhesive composition according to claim 1 or 2, wherein the titanate compound (C) is at least one of barium titanate, strontium titanate, and calcium titanate.

4. The adhesive composition according to any one of claims 1 to 3, containing a silane coupling agent.

5. The adhesive composition according to any one of claims 1 to 4, wherein the acid value of the polyamide compound (A) is 0.1 to 10 mgKOH / g.

6. The adhesive composition according to any one of claims 1 to 5, wherein the epoxy resin (B) has 3 or more epoxy groups in one molecule.

7. The adhesive composition according to any one of claims 1 to 6, wherein the epoxy resin (B) is a cresol novolak type epoxy resin.

8. The adhesive composition according to any one of claims 1 to 7, wherein the content of the epoxy resin (B) is 2 to 25 parts by mass with respect to 100 parts by mass of the content of the polyamide compound (A).

9. A laminate with an adhesive layer, comprising a base film and an adhesive layer composed of the adhesive composition according to any one of claims 1 to 8.

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