Resin composition, bonding film, laminate with resin composition layer, laminate, and electromagnetic shielding film

Abstract

A resin composition comprising a polyester-polyurethane resin (A) and an epoxy resin (B), in which an isocyante component constituting the polyester-polyurethane resin (A) comprises an isocynate compound that has a hydrocarbon group having 8 to 14 carbon atoms; and a bonding film, a laminate with a resin composition layer, a laminate, or an electromagnetic wave shield film, in which the resin composition is used.

Description

[Technical Field]

[0001] The present invention relates to a polyester polyurethane resin composition as an effective component for manufacturing printed circuit boards, particularly flexible printed circuit boards and build-up multilayer printed circuit boards, which has high adhesion to polyimide films and metals, and whose cured product has heat resistance and moisture heat resistance, as well as excellent liquid stability and processability. Furthermore, the present invention relates to a bonding film obtained by attaching the resin composition to a release film, a laminate with a resin composition layer obtained by attaching the resin composition to a base film, a laminate having a layer obtained by curing the resin composition, and an electromagnetic wave shielding film which is suitable for use in shielding electromagnetic noise generated from electrical circuits when attached to flexible printed circuit boards and the like. [Background technology]

[0002] Flexible printed circuit boards (PCBs) are seeing increasing applications because they enable three-dimensional and high-density mounting even in limited spaces. In recent years, with the miniaturization and weight reduction of electronic devices, related products for flexible printed circuit boards have diversified, and demand for them has increased. These related products include flexible copper-clad laminates made by laminating copper foil onto a polyimide film, flexible printed circuit boards with electronic circuits formed on flexible copper-clad laminates, flexible printed circuit boards with reinforcement plates, and multilayer boards made by layering and joining flexible copper-clad laminates or flexible printed circuit boards. For example, when manufacturing flexible copper-clad laminates, adhesives are typically used to bond the polyimide film and copper foil.

[0003] Conventional adhesive compositions or conventional laminates are known as those described in Patent Documents 1 to 3. Patent Document 1 describes a halogen-free flame-retardant adhesive composition comprising (A) a solvent-soluble polyamide resin that is solid at 25°C, (B) a phenoxy resin, (C) an epoxy resin that does not contain halogen atoms, and (D) a phosphorus-based flame retardant having a structure represented by the following general formula (1), wherein the epoxy resin (C) is an epoxy resin having three or more epoxy groups in one molecule, the content of the phenoxy resin (B) is 100 to 450 parts by mass per 100 parts by mass of the polyamide resin (A), the content of the epoxy resin (C) is 1 to 60 parts by mass per 100 parts by mass of the total of the polyamide resin (A) and the phenoxy resin (B), and the content of the phosphorus-based flame retardant (D) is 5 to 100 parts by mass per 100 parts by mass of the total of the polyamide resin (A) and the phenoxy resin (B).

[0004] Furthermore, Patent Document 2 describes a laminate characterized in that a curable resin composition is laminated on at least one side of a polyimide film, a polyester film, or a metal foil, comprising a polyester polymer (a) having two or more carboxyl groups in its molecule, a number average molecular weight of 5,000 to 100,000, and a molecular weight per carboxyl group of 1,500 to 10,000, an epoxy resin (b) having two or more epoxy groups in its molecule, and an epoxy resin curing accelerator (c), and capable of maintaining thermoplasticity for a period of 5 months or more at 5°C; and a laminate in which the curable resin composition of the laminate is cured and laminated on a metal foil (including a metal circuit).

[0005] Furthermore, Patent Document 3 contains a carboxyl group and has an acid value (unit: equivalent / 10 6 g) is between 100 and 1000, and the number-average molecular weight is 5.0 × 10 3 The above 1.0 × 10 5The following describes an adhesive resin composition containing a polyurethane resin (a) having a glass transition temperature of -10°C to 70°C, an epoxy resin (b) containing nitrogen atoms, and an epoxy resin (c) having a dicyclopentadiene skeleton, wherein the blending ratio of resin (b) is 0.1% to 20% by mass of the total epoxy resin contained in the resin composition. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 5846290 [Patent Document 2] Japanese Patent Publication No. 2005-125724 [Patent Document 3] Japanese Patent Publication No. 2010-84005 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that the present invention aims to solve is to provide a resin composition in which the resulting cured product exhibits excellent conductivity regardless of whether it has been stored for a long period (1,000 hours) in a high-temperature, high-humidity environment (85°C, 85%RH) or subjected to a thermal cycling test (e.g., 1,000 cycles at -40°C / 125°C). Another problem that the present invention aims to solve is to provide a bonding film, a laminate with a resin composition layer, a laminate, or an electromagnetic wave shielding film using the resin composition. [Means for solving the problem]

[0008] The means for solving the aforementioned problem include the following embodiments. <1> A resin composition comprising a polyester polyurethane resin (A) and an epoxy resin (B), wherein the diisocyanate component constituting the polyester polyurethane resin (A) contains a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms. <2> The resin (C) further contains a carboxyl group or a carboxylic acid anhydride structure. <1> The resin composition described above. <3> The molecular weight per urethane bond in polyester polyurethane resin (A) is between 200 and 8,000. <1> or <2> The resin composition described above. <4> In the aforementioned resin composition, the content of polyester polyurethane resin (A) is 10% to 90% by mass, and the content of resin having a carboxyl group or carboxylic acid anhydride structure (C) is 5% to 70% by mass, relative to the total amount of polyester polyurethane resin (A), epoxy resin (B), resin having a carboxyl group or carboxylic acid anhydride structure (C), and imidazole silane compound (D) which may be included as an optional component. <1> ~ <3> A resin composition as described in any one of the following. <5> Further contains inorganic filler (E) <1> ~ <4> A resin composition as described in any one of the following. <6> Further contains organic filler (F) <1> ~ <5> A resin composition as described in any one of the following. <7> The diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms has an alicyclic structure. <1> ~ <6> A resin composition as described in any one of the following. <8> The diol component constituting the polyester polyurethane resin (A) contains a diol compound having a hydrocarbon group with 5 to 32 carbon atoms. <1> ~ <7> A resin composition as described in any one of the following. <9> The diol compound having a hydrocarbon group with 5 to 32 carbon atoms includes a diol compound having an alicyclic structure or two or more side chains. <8> The resin composition described above. <10> Polyester polyurethane resin (A) includes a polyester polyurethane resin having a polyester structure with a number average molecular weight of 8,000 to 30,000. <1> ~ <9> A resin composition as described in any one of the following. <11> The number-average molecular weight of the polyester polyurethane resin (A) is between 10,000 and 80,000. <1> ~ <10> A resin composition as described in any one of the following. <12> The resin composition according to any one of <1> to <11>, wherein the acid value of the polyester polyurethane resin (A) is 0.1 mgKOH / g to 20 mgKOH / g. <13> The resin composition according to any one of <1> to <12>, wherein the glass transition temperature of the polyester polyurethane resin (A) is 30°C to 150°C. <14> The resin composition according to any one of <1> to <13>, wherein the content of the epoxy resin (B) is 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the polyester polyurethane resin (A). <15> The resin composition according to any one of <1> to <14>, wherein the epoxy resin (B) contains a bisphenol A type epoxy resin and / or a novolak type epoxy resin. <16> The resin composition according to any one of <1> to <15>, wherein the content of the resin (C) having a carboxy group or a carboxylic anhydride structure is 1 part by mass to 100 parts by mass with respect to 100 parts by mass of the polyester polyurethane resin (A). <17> The resin composition according to any one of <1> to <16>, wherein the resin (C) having a carboxy group or a carboxylic anhydride structure contains at least one of a polyamide resin having an acid value and a resin having an acid-modified polyolefin structure. <18> The resin composition according to any one of <1> to <17>, further containing a metal filler (G). <19> The resin composition according to <18>, wherein the content of the metal filler (G) is 10 parts by mass to 350 parts by mass with respect to the total amount of 100 parts by mass of the polyester polyurethane resin (A), the epoxy resin (B), the resin (C) having a carboxy group or a carboxylic anhydride structure, and the imidazole silane compound (D) which may be contained as an optional component in the resin composition. <20> The resin composition according to <18> or <19>, wherein the metal filler (G) is a conductive filler. <21>A bonding film comprising a B-stage resin composition layer formed by partially curing the resin composition according to any one of <1> to <20> and a release film in contact with at least one surface of the resin composition layer. <22> A resin composition layer made of the resin composition according to any one of <1> to <20>, a B-stage resin composition layer obtained by partially curing the resin composition, or a cured layer obtained by curing the resin composition, and a base material film in contact with at least one surface of the resin composition layer, the B-stage resin composition layer or the cured layer. A laminate with a resin composition layer. <23> A laminate comprising a cured layer obtained by curing the resin composition according to any one of <1> to <20>. <24> A flexible copper-clad laminate comprising a copper foil, a cured layer obtained by curing the resin composition according to any one of <1> to <20>, and a base material. <25> A flexible flat cable comprising a copper wiring, a cured layer obtained by curing the resin composition according to any one of <1> to <20>, and a coating material. <26> An electromagnetic shielding film having a resin composition layer made of the resin composition according to any one of <1> to <20>, a B-stage resin composition layer obtained by partially curing the resin composition, or a cured layer obtained by curing the resin composition.

Advantages of the Invention

[0009] According to the present invention, a resin composition excellent in conductivity can be provided even after long-term storage (1,000 hours) in a high-temperature and high-humidity environment (85 ° C, 85% RH) and after a thermal cycle test (for example, -40 ° C / 125 ° C for 1,000 cycles). Further, according to the present invention, a bonding film using the resin composition, a laminate with a resin composition layer, a laminate or an electromagnetic shielding film can be provided.

Modes for Carrying Out the Invention

[0010] The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, "~" is used to mean including the numerical values described before and after it as the lower limit value and the upper limit value. In numerical ranges described stepwise within this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described stepwise. Furthermore, in numerical ranges described within this specification, the upper or lower limit of that range may be replaced with the values ​​shown in the examples. In the present invention, the amount of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified, if there are multiple substances corresponding to each component in the composition. In this invention, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. In this invention, "mass%" and "weight%" are synonymous, and "parts by mass" and "parts by weight" are synonymous. Furthermore, in the present invention, a combination of two or more preferred embodiments is a more preferred embodiment. Furthermore, in this specification, "(meth)acrylic" refers to both acrylic and methacrylic, or either of them. Furthermore, in some cases, the hydrocarbon chains are described using simplified structural formulas in which the symbols for carbon (C) and hydrogen (H) are omitted. The details of the present invention will be described in detail below.

[0011] (Resin composition) The resin composition of the present invention contains a polyester polyurethane resin (A) and an epoxy resin (B), wherein the diisocyanate component constituting the polyester polyurethane resin (A) contains a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms. The resin composition of the present invention can be suitably used as an adhesive composition, more suitably used as an adhesive composition for bonding polyimide or metal, and particularly suitably used as an adhesive composition for bonding polyimide and metal.

[0012] The inventors have found that conventional resin compositions produce cured products that do not have sufficient conductivity under high-temperature, high-humidity environments and after thermal cycling tests. As a result of diligent research by the present inventors, it has been found that a resin composition containing two types of resins, polyester polyurethane resin (A) and epoxy resin (B), is provided. The diisocyanate component constituting the polyester polyurethane resin (A) contains a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms. Although the detailed mechanism is unknown, these two types of resins act synergistically and complement each other. Furthermore, because the isocyanate component constituting the polyester polyurethane resin (A) contains a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms, the hydrophobicity and moisture resistance of the resin are improved. As a result, the cured product exhibits excellent conductivity even under high temperature and high humidity conditions. Moreover, due to the stress relaxation effect of the resin components of polyester polyurethane resin (A) and epoxy resin (B), it is possible to provide a resin composition that exhibits excellent conductivity even after a thermal cycle test.

[0013] Furthermore, the resin composition of the present invention contains two types of resins, polyester polyurethane resin (A) and epoxy resin (B), and the molecular weight per urethane bond in the polyester polyurethane resin (A) is 200 to 8,000, and the diisocyanate component constituting the polyester polyurethane resin (A) contains a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms, thereby exhibiting excellent flame retardancy, conductivity both initially and after soldering, and heat resistance.

[0014] The present invention will be described in detail below. Furthermore, in this specification, "polyester polyurethane resin (A)," etc., are also referred to as "component (A)," etc.

[0015] <Polyester polyurethane resin (A)> The resin composition of the present invention contains a polyester polyurethane resin (A), and the diisocyanate component constituting the polyester polyurethane resin (A) contains a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms. The polyester polyurethane resin (A) may be any resin having two or more ester bonds and two or more urethane bonds, but it is preferable that it is a resin having a polyester chain and two or more urethane bonds. Furthermore, the polyester polyurethane resin (A) is preferably a resin obtained by reacting at least a polyester polyol, a polyisocyanate, and a chain extender as raw materials, and more preferably a resin obtained by reacting at least a polyester polyol, a polyisocyanate, and a diol compound.

[0016] In the polyester polyurethane resin (A), the polyester portion is preferably formed from an acid component and an alcohol component. As the acid component, polycarboxylic acid compounds are preferred, and dicarboxylic acid compounds are more preferred. Sulfocarboxylic acid compounds and the like can also be used as the acid component. Furthermore, aromatic acids are particularly preferred as the acid component. As the alcohol component, polyhydric alcohol compounds are preferred, and diol compounds are more preferred. Furthermore, the polyester portion may be formed from a hydroxycarboxylic acid compound. When the total amount of all acidic components constituting the polyester portion of the polyester polyurethane resin (A) is set to 100 mol%, from the viewpoint of adhesion, heat resistance, and heat and humidity resistance, it is preferable that aromatic acids make up 30 mol% or more, more preferably 45 mol% or more, and particularly preferable 60 mol% or more of the total acidic components.

[0017] Examples of aromatic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and 5-hydroxyisophthalic acid. Other examples include aromatic dicarboxylic acids having a sulfonic acid group or sulfonic acid base, such as sulfoterephthalic acid, 5-sulfisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, 5-(4-sulfophenoxy)isophthalic acid, sulfoterephthalic acid, their metal salts, and their ammonium salts; and aromatic oxycarboxylic acids such as p-hydroxybenzoic acid, p-hydroxyphenylpropionic acid, p-hydroxyphenylacetic acid, 6-hydroxy-2-naphthoic acid, and 4,4-bis(p-hydroxyphenyl)valeric acid. Among these, from the viewpoint of adhesion, it is preferable that the acid component contains terephthalic acid and / or isophthalic acid, and particularly preferable that it contains terephthalic acid and / or isophthalic acid. Furthermore, the acid component may be a derivative of an acid compound such as an ester during resin synthesis.

[0018] Other acidic components include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid and their acid anhydrides, and aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer acid.

[0019] On the other hand, preferred polyhydric alcohol components include aliphatic diol compounds, alicyclic diol compounds, aromatic-containing diol compounds, and ether-bond-containing diol compounds. Examples of aliphatic diol compounds include ethylene glycol, 1,2-propylenediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-butyl-2-ethyl-1,3-propanediol, neopentyl glycol hydroxypivalate ester, dimethylolheptane, and 2,2,4-trimethyl-1,3-pentanediol. Examples of alicyclic diol compounds include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, tricyclodecanediol, tricyclodecanedimethylol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adducts and propylene oxide adducts of hydrogenated bisphenol A, and the like. Examples of aromatic diol compounds include glycols obtained by adding 1 to several moles of ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, such as paraxylene glycol, metaxylene glycol, orthoxylene glycol, 1,4-phenylene glycol, ethylene oxide adducts of 1,4-phenylene glycol, bisphenol A, ethylene oxide adducts of bisphenol A, and propylene oxide adducts. Examples of ether-bonded diol compounds include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol ethylene oxide adduct, and neopentyl glycol propylene oxide adduct. Among these diols, diols having side chains, such as neopentyl glycol and 2-butyl-2-ethyl-1,3-propanediol, are preferred due to their compatibility with epoxy resins, resins having carboxyl groups or carboxylic acid anhydride structures, and their solution stability. In other words, the diol component constituting the polyester polyurethane resin (A) preferably contains a diol having a side chain, from the viewpoint of compatibility with epoxy resins, resins having a carboxyl group or carboxylic acid anhydride structure, etc., and solution stability. In particular, from the viewpoint of compatibility with epoxy resins, resins having carboxyl groups or carboxylic acid anhydride structures, solution stability, and conductivity, it is more preferable that the chain extender constituting the polyester polyurethane resin (A) contains a diol having side chains. That is, from the viewpoint of compatibility with epoxy resins, resins having carboxyl groups or carboxylic acid anhydride structures, solution stability, and conductivity, it is more preferable that the polyester polyurethane resin (A) is a resin obtained by reacting at least a polyester polyol, a polyisocyanate, and a diol having side chains as its raw materials. In diols having a side chain, the side chain is preferably an alkyl group, and the number of carbon atoms in the alkyl group may be, for example, 1, 2, 3, 4, or 5. This is also true for diols having a side chain described later. Examples of diols having side chains include neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethylolpropionic acid.

[0020] From the viewpoint of conductivity in the initial stage of the cured product, after soldering, after long-term reliability testing, or after thermal cycling testing, the polyester polyurethane resin (A) is preferably composed of at least a diol component. Furthermore, the diol component constituting the polyester polyurethane resin (A) preferably contains a diol compound having a hydrocarbon group with 5 to 32 carbon atoms, more preferably contains a diol compound having a hydrocarbon group with 5 to 16 carbon atoms, and particularly preferably contains a diol compound having a hydrocarbon group with 7 to 12 carbon atoms, from the viewpoint of conductivity in the initial stage of the cured product, after soldering, after long-term reliability testing, or after thermal cycling testing. The diol compound having a hydrocarbon group with 5 to 32 carbon atoms preferably includes a alicyclic structure or a diol compound having two or more side chains, more preferably includes a diol compound having two or more side chains, and particularly preferably includes a diol compound having two side chains, from the viewpoint of conductivity in the initial stage of the cured product, after soldering, after long-term reliability testing, or after thermal cycling testing. Furthermore, the diol compound having a hydrocarbon group with 5 to 32 carbon atoms may be either a diol component constituting the polyester portion or a diol component constituting the polyurethane portion. However, from the viewpoint of conductivity in the initial stage of the cured product, after soldering, after long-term reliability testing, or after thermal cycling testing, it is preferable that it be a diol component constituting the polyurethane portion.

[0021] Furthermore, hydroxycarboxylic acid compounds having both a hydroxyl group and a carboxyl group in their molecular structure can also be used as polyester raw materials, such as 5-hydroxyisophthalic acid, p-hydroxybenzoic acid, p-hydroxyphenityl alcohol, p-hydroxyphenylpropionic acid, p-hydroxyphenylacetic acid, 6-hydroxy-2-naphthoic acid, and 4,4-bis(p-hydroxyphenyl)valeric acid.

[0022] As a component constituting the polyester portion of the polyester polyurethane resin (A), trifunctional or higher polycarboxylic acids and / or polyols may be copolymerized in an amount of approximately 0.1 mol% to 5 mol% relative to the total acid components or total polyhydric alcohol components constituting the polyester portion, for the purpose of introducing a branched skeleton as needed. In particular, when reacting with a curing agent to obtain a cured layer, introducing a branched skeleton increases the concentration of end groups (reaction sites) in the resin, resulting in a cured layer with a high crosslink density. Examples of polycarboxylic acids with three or more functions in this case include trimellitic acid, trimesic acid, ethylene glycol bis(anhydrotrimellitate), glycerol tris(anhydrotrimellitate), trimellitic anhydride, pyromellitic anhydride (PMDA), oxydiphthalic acid dianhydride (ODPA), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), 3,3',4,4'-diphenyltetracarboxylic acid dianhydride (BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride (DSDA), 4,4'-(hexafluoroisopropylidene)diphthalic acid dianhydride (6FDA), and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride (BSAA). On the other hand, examples of polyols with three or more functions include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. When using trifunctional or higher polycarboxylic acids and / or polyols, copolymerization is preferably carried out in an amount of 0.1 mol% to 5 mol%, more preferably 0.1 mol% to 3 mol%, relative to the total acid component or total polyhydric alcohol component.

[0023] In the polyester portion of the polyester polyurethane resin (A), acid addition of approximately 0.1 mol% to 10 mol% can be performed on the total acid components or total polyhydric alcohol components constituting the polyester portion, if necessary, for the purpose of introducing carboxyl groups. When monocarboxylic acids, dicarboxylic acids, or polyfunctional carboxylic acid compounds are used for acid addition, a decrease in molecular weight occurs due to transesterification, so it is preferable to use acid anhydrides. Examples of acid anhydrides that can be used include succinic anhydride, maleic anhydride, orthophthalic acid, 2,5-norbornenedicarboxylic acid anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride (PMDA), oxydiphthalic acid dianhydride (ODPA), 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA), 3,3',4,4'-diphenyltetracarboxylic acid dianhydride (BPDA), 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride (DSDA), 4,4'-(hexafluoroisopropylidene)diphthalic acid dianhydride (6FDA), and 2,2'-bis[(dicarboxyphenoxy)phenyl]propane dianhydride (BSAA). Acid addition can be carried out directly in the bulk state after polyester polycondensation, or by dissolving the polyester before addition. The reaction in the bulk state is fast, but gelation can occur if a large amount of acid is added, and since the reaction takes place at high temperatures, precautions such as blocking oxygen gas and preventing oxidation are necessary. On the other hand, acid addition in solution state is slower, but it allows for the stable introduction of a large amount of carboxyl groups.

[0024] The polyurethane portion of the polyester polyurethane resin (A) is composed of at least a diisocyanate component. Furthermore, the diisocyanate component includes a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms. Here, the methylene group in the hydrocarbon group may be replaced with an unreactive bond such as -O-, -S-, -CO-, -COO-, or -OCO-. The amount of the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms in the diisocyanate component is usually 70 mol% or more, preferably 90 mol% or more, and may be 100 mol%. Furthermore, the polyurethane portion of the polyester polyurethane resin (A) may be composed of monofunctional or trifunctional or more isocyanate components in addition to the diisocyanate component. In the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms, the number of carbon atoms in the hydrocarbon group is preferably 8 to 12, and more preferably 8 to 10, from the viewpoint of conductivity after soldering, long-term reliability testing, and thermal cycling testing of the resulting cured product. Furthermore, the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms is preferably alicyclic in structure from the viewpoint of conductivity after soldering, long-term reliability testing, and thermal cycling testing of the resulting cured product.

[0025] From the viewpoint of adhesion, the polyester polyurethane resin (A) preferably contains 5 to 50 molar equivalents of diisocyanate component per molar equivalent of polyester portion. In other words, from the viewpoint of adhesion, the polyester polyurethane resin (A) preferably contains 10 to 100 molar equivalents of urethane bonds per molar equivalent of polyester portion.

[0026] The polyisocyanate used in the production of polyester polyurethane resin (A) may be one of the following: diisocyanate, its dimer (uretdione), its trimer (isocyanurate, triol adduct, biuret), or a mixture of two or more of these. For example, diisocyanate components include diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-biphenylenediisocyanate, 1,5-naphthalene diisocyanate, 2,6-naphthalene diisocyanate, 4,4'-diisocyanate diphenyl ether, m-xylylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, methylenebis(4-cyclohexyl diisocyanate), isophorone diisocyanate, norbornane diisocyanate, norbornene diisocyanate, etc. In particular, aliphatic or alicyclic diisocyanate compounds are preferred from the viewpoint of transparency and conductivity of the resulting cured product after soldering, long-term reliability testing, and thermal cycling testing, with alicyclic diisocyanate compounds being especially preferred. Furthermore, from the viewpoint of availability and conductivity after thermal cycling testing, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, methylenebis(4-cyclohexyl diisocyanate), or norbornane diisocyanate are preferred, with 1,3-bis(isocyanatomethyl)cyclohexane being especially preferred.

[0027] In the manufacture of polyester polyurethane resin (A), chain extenders may be used as necessary. Examples of chain extenders include diol compounds already described as components of the polyester portion, and compounds having one carboxyl group and two hydroxyl groups, such as dimethylolpropionic acid and dimethylolbutanoic acid. Among these, diol compounds are preferred as chain extenders from the viewpoint of conductivity, diol compounds having side chains are more preferred, and diol compounds having branched chains are particularly preferred. From the viewpoint of conductivity, the diol compound having a side chain preferably contains at least one compound selected from the group consisting of neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethylolpropionic acid, and it is particularly preferable that it contains at least one compound selected from the group consisting of neopentyl glycol and 2-butyl-2-ethyl-1,3-propanediol, and 2,2-dimethylolpropionic acid. Polyamino compounds may be used as chain extenders, but in one embodiment, the polyester polyurethane resin (A) may be preferable if it does not contain urea bonds.

[0028] There are no particular limitations on the method for producing the polyester polyurethane resin (A), and known methods can be used. For example, the polyester polyol and polyisocyanate, and optionally the chain extender, may be charged together in the reaction vessel, or they may be charged separately. In any case, the ratio of isocyanate group / hydroxyl group functional groups to the total hydroxyl value of the polyester polyol and chain extender in the system and the total isocyanate groups of the polyisocyanate is preferably 0.9 to 1.1, more preferably 0.98 to 1.02, and particularly preferably 1. This reaction can be carried out in the presence or absence of a solvent that is inert to the isocyanate groups. Examples of solvents include ester solvents (ethyl acetate, butyl acetate, ethyl butyrate, etc.), ether solvents (dioxane, tetrahydrofuran, diethyl ether, etc.), ketone solvents (cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, etc.), aromatic hydrocarbon solvents (benzene, toluene, xylene, etc.), and mixtures thereof. However, from the viewpoint of reducing environmental impact, ethyl acetate and methyl ethyl ketone are preferred. The reaction apparatus is not limited to reaction vessels equipped with stirring devices; mixing and kneading devices such as kneaders and twin-screw extruders can also be used.

[0029] To accelerate the urethane reaction, catalysts commonly used in urethane reactions, such as tin-based catalysts (trimethyltin laurate, dimethyltin dilaurate, trimethyltin hydrooxide, dimethyltin dihydrooxide, stanus octoate, etc.), lead-based catalysts (red oleate, red-2-ethylhexoate, etc.), and amine-based catalysts (triethylamine, tributylamine, morpholine, diazabicyclooctane, diazabicycloundecene, etc.), can be used.

[0030] The glass transition temperature (Tg) of the polyester portion of the polyester polyurethane resin (A) is preferably 40°C to 150°C, more preferably 45°C to 120°C, even more preferably 50°C to 90°C, and particularly preferably 60°C to 70°C, from the viewpoint of adhesion, conductivity, and heat resistance. Furthermore, the glass transition temperature (Tg) of the polyester polyurethane resin (A) is preferably 30°C to 150°C, more preferably 40°C to 140°C, even more preferably 50°C to 90°C, and particularly preferably 60°C to 70°C, from the viewpoint of adhesion, conductivity, and heat resistance.

[0031] The number-average molecular weight (Mn) of the polyester polyurethane resin (A) is preferably 5,000 to 100,000, more preferably 10,000 to 80,000, even more preferably 20,000 to 60,000, and particularly preferably 25,000 to 50,000, from the viewpoint of conductivity and heat resistance. The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the resin in this invention can be obtained by gel permeation chromatography (GPC).

[0032] In polyester polyurethane resin (A), the molecular weight per urethane bond is preferably 200 to 8,000, more preferably 200 to 5,000, even more preferably 300 to 2,000, particularly preferably 400 to 1,500, and most preferably 700 to 1,000, from the viewpoint of conductivity and heat resistance. For example, in polyester polyurethane resin (A), if there are 40 urethane bonds per molecule and the number-average molecular weight is 32,000, then 32,000 / 40 = 800, and the molecular weight per urethane bond is 800. Similarly, if polyester polyurethane resin (A) has X urethane bonds per molecule and the number-average molecular weight is Y, then the molecular weight per urethane bond in polyester polyurethane resin (A) is Y / X. When calculating from the raw material composition, the number of moles of isocyanate groups reacted with 1 mole of polyester polyol, which is the raw material for polyester polyurethane resin (A), can also be considered as the "number of urethane bonds in polyester polyurethane resin (A)".

[0033] The acid value of the polyester polyurethane resin (A) is preferably 0 mg KOH / g to 50 mg KOH / g, more preferably 0.1 mg KOH / g to 20 mg KOH / g, even more preferably 0.1 mg KOH / g to 5 mg KOH / g, and particularly preferably 1.0 mg KOH / g to 5.0 mg KOH / g, from the viewpoint of adhesion and conductivity. Furthermore, from the viewpoint of heat resistance, the acid value of the polyester polyurethane resin (A) is preferably 20 mg KOH / g or less, and particularly preferably 5.0 mg KOH / g or less. The method for measuring the acid value of a resin in this invention involves neutralizing the sample with potassium hydroxide benzyl alcohol solution using phenolphthalein solution as an indicator and determining the acid value.

[0034] In particular, the polyester polyurethane resin (A) preferably contains a polyester polyurethane resin having a polyester structure with a number average molecular weight of 1,000 to 50,000, more preferably contains a polyester polyurethane resin having a polyester structure with a number average molecular weight of 2,000 to 40,000, even more preferably contains a polyester polyurethane resin having a polyester structure with a number average molecular weight of 3,000 to 30,000, particularly preferably contains a polyester polyurethane resin having a polyester structure with a number average molecular weight of 8,000 to 30,000, and most preferably contains a polyester polyurethane resin having a polyester structure with a number average molecular weight of 15,000 to 30,000.

[0035] The resin composition of the present invention may contain one type of polyester polyurethane resin (A) or two or more types. From the viewpoint of adhesion, conductivity, and heat resistance, the content of polyester polyurethane resin (A) is preferably 5% to 90% by mass, more preferably 10% to 80% by mass, even more preferably 20% to 75% by mass, and particularly preferably 30% to 70% by mass, based on the total solid content of the resin composition. Furthermore, from the viewpoint of adhesion, conductivity, and heat resistance, the content of polyester polyurethane resin (A) is preferably 5% to 90% by mass, more preferably 10% to 90% by mass, even more preferably 10% to 70% by mass, and particularly preferably 30% to 70% by mass, based on the total amount of polyester polyurethane resin (A), epoxy resin (B), resin having a carboxyl group or carboxylic acid anhydride structure (C), and imidazole silane compound (D) which may be included as an optional component in the resin composition.

[0036] <Epoxy resin (B)> The resin composition of the present invention contains epoxy resin (B). The epoxy resin (B) is a component that provides adhesion and heat resistance in the cured area after bonding. In this invention, the epoxy resin (B) includes not only high-molecular-weight compounds having epoxy groups, but also low-molecular-weight compounds having epoxy groups. It is preferable that the number of epoxy groups in the epoxy resin (B) is two or more. Examples of epoxy resin (B) include glycidyl esters such as diglycidyl orthophthalate, diglycidyl isophthalate, diglycidyl terephthalate, diglycidyl p-hydroxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl succinate, diglycidyl adipic acid, diglycidyl sebacate, and triglycidyl trimellitic acid; diglycidyl ether of bisphenol A and its oligomers, ethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. Examples include glycidyl ethers such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, sorbitol polyglycidyl ether, and polyglycerol polyglycidyl ether; and novolac-type epoxy resins such as phenol novolac epoxy resin, o-cresol novolac epoxy resin, and bisphenol A novolac epoxy resin. Furthermore, flame-retardant brominated bisphenol A type epoxy resin, phosphorus-containing epoxy resin, dicyclopentadiene skeleton-containing epoxy resin, naphthalene skeleton-containing epoxy resin, anthracene type epoxy resin, tert-butylcatechol type epoxy resin, biphenyl type epoxy resin, and bisphenol S type epoxy resin can also be used. In particular, epoxy resin (B) is preferably made up of bisphenol A type epoxy resin and / or novolac type epoxy resin, from the viewpoint of adhesion and heat resistance.

[0037] In the present invention, in order to exhibit high heat resistance after curing, it is preferable that the epoxy resin (B) contains a compound having three or more epoxy groups in one molecule. When such a compound is used, the crosslinking reactivity with the polyester urethane resin (A) and the resin (C) having a carboxyl group or carboxylic acid anhydride structure is increased compared to when an epoxy resin with two epoxy groups is used, and sufficient heat resistance can be obtained. From the viewpoint of heat resistance, the content of compounds having three or more epoxy groups in one molecule in epoxy resin (B) is preferably 15% by mass or more, more preferably 20% by mass or more, and particularly preferably 25% by mass or more, based on the total mass of epoxy resin (B).

[0038] The resin composition of the present invention may contain one epoxy resin (B) alone, or it may contain two or more epoxy resins. The content of epoxy resin (B) is preferably 1% to 60% by mass, more preferably 2% to 40% by mass, and particularly preferably 3% to 20% by mass, based on the total amount of polyester polyurethane resin (A), epoxy resin (B), resin having a carboxyl group or carboxylic acid anhydride structure (C) in the resin composition, and imidazole silane compound (D) which may be included as an optional component, from the viewpoint of adhesion, conductivity, and heat resistance.

[0039] <Resin having a carboxyl group or carboxylic acid anhydride structure (C)> From the viewpoint of conductivity after soldering, long-term reliability testing, and thermal cycling testing of the resulting cured product, the resin composition of the present invention preferably contains a resin (C) having a carboxyl group or a carboxylic acid anhydride structure. The resin (C) having a carboxyl group or carboxylic acid anhydride structure is preferably solid at 25°C. The resin (C) having a carboxyl group or carboxylic acid anhydride structure is not particularly limited as long as it is soluble in the organic solvents described later. Specific examples include polyamide resins, polyolefin resins, acrylic resins, and copolymers thereof. In particular, the resin (C) having a carboxyl group or carboxylic acid anhydride structure preferably contains at least one resin selected from the group consisting of polyamide resins, polyolefin resins and copolymers thereof, from the viewpoint of conductivity of the resulting cured product after soldering, after long-term reliability testing and after thermal cycling testing, more preferably contains at least one of a polyamide resin having an acid value and a resin having an acid-modified polyolefin structure, and particularly preferably contains a polyamide resin having an acid value.

[0040] Polyamide resin is a condensed resin obtained using a dibasic acid and a diamine as monomers, preferably a resin obtained using two or more dibasic acids and two or more diamines. Specific examples of the dibasic acid include adipic acid, sebacic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, dimer acid, isophthalic acid, terephthalic acid, and sodium 5-sulfoisophthalate. Specific examples of the diamine include hexamethylenediamine, heptamethylenediamine, p-diaminomethylcyclohexane, bis(p-aminocyclohexyl)methane, m-xylenediamine, piperazine, and isophoronediamine. The polyamide resin may also be a block copolymer. The inclusion of piperazine in the aforementioned diamine component is preferable for improved adhesion. The piperazine content is preferably 1.0 mol% or more, and more preferably 20 mol% or more, when the total amount of diamine components constituting the resin (C) having a carboxyl group or carboxylic acid anhydride structure is taken as 100 mol%. Polyamide resins exhibit excellent solubility in solvents, especially when they contain structural units derived from aliphatic dibasic acids and structural units derived from alicyclic diamines. Furthermore, adhesive compositions containing such polyamide resins are preferable because they show almost no increase in viscosity even after long-term storage and exhibit good adhesion to a wide range of substrates.

[0041] The polyamide resin may contain constituent units derived from aminocarboxylic acids, lactams, etc. Specifically, examples of aminocarboxylic acids include 11-aminoundecanoic acid, 12-aminododecanoic acid, 4-aminomethylbenzoic acid, and 4-aminomethylcyclohexanecarboxylic acid, while examples of lactams include ε-caprolactam, ω-laurolactam, α-pyrrolidone, and α-piperidone.

[0042] Furthermore, the polyamide resin may appropriately contain structural units derived from polyalkylene glycol for the purpose of imparting flexibility. Specific examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, block or random copolymers of ethylene oxide and propylene oxide, and block or random copolymers of ethylene oxide and tetrahydrofuran. The structural units derived from polyalkylene glycol may be included individually or in combination of two or more types.

[0043] Polyamide resins can have compositions such as nylon 6 / nylon 66 copolymer, nylon 6 / nylon 6-10 copolymer, nylon 6 / nylon 66 / nylon 6-10 copolymer, nylon 6 / nylon 66 / nylon 11 copolymer, nylon 6 / nylon 66 / nylon 12 copolymer, nylon 6 / nylon 6-10 / nylon 6-11 copolymer, nylon 6 / nylon 11 / isophoronediamine copolymer, nylon 6 / nylon 66 / nylon 6 copolymer, and nylon 6 / nylon 6-10 / nylon 12 copolymer.

[0044] Next, the modified polyamide resin is obtained by adding formaldehyde and alcohol to an unmodified polyamide resin and introducing alkoxymethyl groups to the nitrogen atoms constituting the amide bonds, thereby creating an alcohol-soluble nylon resin. Specifically, examples include modified polyamide resins in which 6-nylon, 66-nylon, etc., have been alkoxymethylated. The introduction of N-alkoxymethyl groups contributes to a lower melting point, increased flexibility, and improved solubility in solvents, and the introduction rate is appropriately set according to the purpose.

[0045] There are no particular limitations on the resin having a polyolefin structure, but examples include polyethylene, polypropylene, polybutene, and copolymers thereof. Furthermore, the resin having a polyolefin structure may be a copolymer of an olefin with another ethylenically unsaturated compound, or a block copolymer of a polyolefin with a polycondensation resin. For example, the resin having a polyolefin structure may be a styrene-based resin such as styrene-butadiene copolymer, styrene-butadiene-styrene block copolymer, styrene-ethylene / propylene-styrene block copolymer, styrene-ethylene / butylene-styrene block copolymer, styrene-isoprene / butadiene-styrene block copolymer, or styrene-isoprene-styrene block copolymer. In particular, among resins having an acid-modified polyolefin structure, it is preferable that the resin is an acid-modified polyolefin resin.

[0046] Furthermore, there are no particular limitations on the method for introducing a carboxyl group or a carboxylic acid anhydride structure into the polyamide resin and the resin having a polyolefin structure, but examples include copolymerizing an unsaturated carboxylic acid anhydride and modifying the resin with a carboxylic acid anhydride. Specifically, examples include a resin obtained by graft polymerization of an unsaturated carboxylic acid anhydride such as maleic anhydride, itaconic anhydride, acrylic acid, or methacrylic acid into a polyolefin resin such as polypropylene; a polyamide resin having an acid terminus obtained by reacting a dibasic acid in excess with a diamine; a resin obtained by reacting a carboxylic acid anhydride with a polyamide resin; and a polyamide resin using a compound having two or more carboxylic acid anhydride structures, such as pyromellitic anhydride, as the carboxylic acid component of the raw material.

[0047] The acid value of resin (C) having a carboxyl group or carboxylic acid anhydride structure is not particularly limited, as long as it has at least a carboxyl group or carboxylic acid anhydride structure, but is preferably 0.1 mg KOH / g to 200 mg KOH / g, more preferably 1 mg KOH / g to 100 mg KOH / g, even more preferably 2 mg KOH / g to 50 mg KOH / g, and particularly preferably 5 mg KOH / g to 30 mg KOH / g.

[0048] The amine value of the resin (C) having a carboxyl group or carboxylic acid anhydride structure is not particularly limited. Generally, a high amine value of the polyamide resin allows for a rapid reaction between the amino group and the epoxy group, resulting in good curability with short heating times. However, immediately after mixing the resin (C) having a carboxyl group or carboxylic acid anhydride structure with the epoxy resin (B), the reaction proceeds gradually, causing a significant increase in the viscosity of the composition or gelation. Therefore, by selecting the amine value of the resin (C) having a carboxyl group or carboxylic acid anhydride structure, both curability and stability can be achieved. The preferred range for the amine value of the resin (C) having a carboxyl group or carboxylic acid anhydride structure is 1 mg KOH / g to 6 mg KOH / g.

[0049] Furthermore, the melting point of the resin (C) having a carboxyl group or carboxylic acid anhydride structure is not particularly limited, but from the viewpoint of solubility in solvents and heat resistance of the cured product, it is preferably in the range of 50°C to 220°C, and more preferably in the range of 70°C to 180°C.

[0050] Examples of solvents for dissolving resin (C) having a carboxyl group or carboxylic acid anhydride structure include alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutyl alcohol, n-butyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diacetone alcohol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and isophorone; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and mesitylene; and esters such as methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate. These solvents may be used individually or in combination of two or more.

[0051] The resin composition of the present invention may contain one resin (C) having a carboxyl group or a carboxylic acid anhydride structure, or it may contain two or more resins. The content of the resin (C) having a carboxyl group or carboxylic acid anhydride structure is preferably 5% to 90% by mass, more preferably 5% to 70% by mass, and particularly preferably 30% to 50% by mass, based on the total amount of the polyester polyurethane resin (A), epoxy resin (B), and resin (C) having a carboxyl group or carboxylic acid anhydride structure, as well as the imidazole silane compound (D) which may be included as an optional component, from the viewpoint of adhesion, conductivity, and heat resistance. Furthermore, in the resin composition of the present invention, from the viewpoint of adhesion, conductivity, and heat resistance, it is preferable that the content of polyester polyurethane resin (A) is 10% to 90% by mass, and the content of resin having a carboxyl group or carboxylic acid anhydride structure (C) is 5% to 70% by mass, relative to the total amount of polyester polyurethane resin (A), epoxy resin (B), resin having a carboxyl group or carboxylic acid anhydride structure (C), and imidazole silane compound (D) which may be included as an optional component in the resin composition.

[0052] Furthermore, in the resin composition of the present invention, from the viewpoint of adhesion, conductivity, and heat resistance, the content of resin (C) having a carboxyl group or carboxylic acid anhydride structure is preferably 1 to 100 parts by mass, preferably 20 to 100 parts by mass, more preferably 50 to 95 parts by mass, and particularly preferably 70 to 90 parts by mass, per 100 parts by mass of polyester polyurethane resin (A). Furthermore, the content of resin (C) having a carboxyl group or carboxylic acid anhydride structure is preferably less than or equal to the content of polyester polyurethane resin (A), and more preferably less than the content of polyester polyurethane resin (A), from the viewpoint of adhesion, conductivity, and heat resistance.

[0053] The content of the polyester polyurethane resin (A) and the resin having a carboxyl group or carboxylic acid anhydride structure (C) in the resin composition is preferably 50% to 98% by mass, more preferably 70% to 97% by mass, and particularly preferably 75% to 95% by mass, based on the total amount of the polyester polyurethane resin (A), epoxy resin (B), and resin having a carboxyl group or carboxylic acid anhydride structure (C) in the resin composition, as well as the imidazole silane compound (D) which may be included as an optional component, from the viewpoint of adhesion, conductivity, and heat resistance.

[0054] <Imidazole silane compound (D)> From the viewpoints of conductivity and adhesiveness, the resin composition of the present invention preferably contains an imidazole silane compound (D). The imidazole silane compound (D) is a compound having one or more imidazole ring structures and one or more silane structures, and is presumed to act as a curing agent for the epoxy resin (B). From the viewpoints of conductivity and adhesiveness, the imidazole silane compound (D) is preferably a compound having one imidazole ring structure and one silyl group. Moreover, as the imidazole silane compound (D), from the viewpoints of conductivity and adhesiveness, a compound represented by the following formula (D) or an acid adduct thereof is preferably mentioned.

[0055]

Chemical formula

[0056] In formula (D), R 1 and R 2 each independently represent a hydrogen atom, a saturated hydrocarbon group, an unsaturated hydrocarbon group or an aryl group, and each of the above groups may have a substituent. R 3 and R 4 each independently represent a hydrogen atom or an alkyl group. At least one of R 3 is an alkyl group, and the alkyl group may have a substituent. n represents an integer of 1 to 3. R 5 represents an alkylene group or a group in which a part of the alkylene group is substituted with at least one of formulas (D2) to (D5).

[0057]

Chemical formula

[0058] In formulas (D2), (D3) and (D5), R 6 represents a hydrogen atom or a hydroxy group. R 7 represents a hydrogen atom, an alkyl group or an aryl group. R 8 and R 9Each of these independently represents a hydrogen atom, an alkyl group, or an aryl group, and each of these groups may have substituents, and the wavy lines indicate the bonding position with other structures.

[0059] The presence of an imidazole silane compound (D), particularly the compound represented by formula (D), improves adhesion to metals, especially gold-plated copper foil. This is presumed to be because the silane structure and the imidazole ring structure exhibit high affinity to both the metal surface and the resin (C) having a carboxyl group or carboxylic acid anhydride structure, and the interaction between them improves adhesion. Furthermore, since the imidazole ring structure can also react with epoxy resin (B), it is presumed that this adhesion-enhancing effect can be maintained even in the reflow process described later.

[0060] The imidazolesilane compound (D) is preferably a compound that has both an imidazole ring structure as the first functional group and an alkoxysilyl group as the second functional group in a single molecule. The imidazole ring in the imidazole ring structure may have substituents such as saturated hydrocarbon groups or unsaturated hydrocarbon groups. In equation (D), R 1 , R 2 , R 3 and R 4 When it is an alkyl group, the preferred number of carbon atoms is 1 to 3. Examples of imidazole ring structures that constitute the imidazolesilane compound (D) include imidazole ring structures, 2-alkylimidazole ring structures, 2,4-dialkylimidazole ring structures, and 4-vinylimidazole ring structures. In the imidazolesilane compound (D), it is preferable that the alkoxysilyl group and the imidazole ring structure are bonded via an alkylene group, or a group in which a portion of the alkylene group is substituted with at least one of formulas (D2) to (D5). R in equation (D) 5 The number of carbon atoms in the alkylene group is preferably 1 to 10, and more preferably 3 to 7. Imidazole silane compounds (D) can be suitably synthesized, for example, by the reaction of an imidazole compound with a 3-glycidoxyalkylsilane compound. Furthermore, the imidazole silane compound (D) may be a silanol compound produced by hydrolysis of an alkoxysilyl group, a polyorganosiloxane compound produced by a dehydration condensation reaction of a silanol compound, or a mixture thereof. Furthermore, examples of acids that can be added to the compound represented by formula (D) include acetic acid, lactic acid, salicylic acid, benzoic acid, adipic acid, phthalic acid, citric acid, tartaric acid, maleic acid, trimellitic acid, phosphoric acid, and isocyanuric acid. These can be used individually or in combination of two or more.

[0061] Furthermore, from the viewpoint of conductivity and adhesion, the imidazolesilane compound (D) is more preferably a compound represented by the following formula (D6) or formula (D7), or an acid adduct thereof.

[0062] [ka]

[0063] In equations (D6) and (D7), R 1 and R 2 Each of these independently represents a hydrogen atom, a saturated hydrocarbon group, an unsaturated hydrocarbon group, or an aryl group, and each of the said groups may have substituents, R 3 and R 4 Each of these independently represents a hydrogen atom or an alkyl group, and R 3 At least one of them is an alkyl group, and the alkyl group may have substituents, n represents an integer from 1 to 3, R 5’ represents an alkylene group, R 6 represents a hydrogen atom or a hydroxyl group.

[0064] R in equations (D6) and (D7) 5’ The number of carbon atoms in the alkylene group is preferably 1 to 10, and more preferably 3 to 7.

[0065] Specific examples of imidazolesilane compounds (D) include 1-(2-hydroxy-3-trimethoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-triethoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-tripropoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-tributoxysilylpropoxypropyl)imidazole, 1-(2-hydroxy-3-triethoxysilylpropoxypropyl)-2-methylimidazole, 1-(2-hydroxy-3-triethoxysilylpropoxypropyl)-4-methylimidazole, 1-(3-oxo-4-trimethoxysilylpropoxypropyl)imidazole, and 1-(3-trimethoxysilylpropylamino)imidazole.

[0066] Among these, the compound represented by formula (D6) or formula (D7) or its acid adduct is preferred because it has good heat resistance and good solubility in solvents, and the acid adduct of the compound represented by formula (D6) is more preferred.

[0067] The compound represented by formula (D6) can be suitably obtained by reacting an imidazole compound such as imidazole, 2-alkylimidazole, 2,4-dialkylimidazole, or 4-vinylimidazole with a 3-glycidoxypropylsilane compound such as 3-glycidoxypropyltrialkoxysilane, 3-glycidoxypropyldialkoxyalkylsilane, or 3-glycidoxypropylalkoxydialkylsilane. Of these, the reaction product of imidazole and 3-glycidoxypropyltrimethoxysilane is particularly preferred. The compound represented by formula (D7) can be suitably obtained by reacting an imidazole compound with 3-methacryloyloxypropyltrimethoxysilane or the like.

[0068] The resin composition of the present invention may contain one imidazolesilane compound (D) alone or two or more imidazolesilane compounds. From the viewpoint of conductivity and adhesion, the content of the imidazole silane compound (D) is preferably 0.05% to 20% by mass, more preferably 0.1% to 10% by mass, and particularly preferably 1% to 5% by mass, based on the total amount of the polyester polyurethane resin (A), epoxy resin (B), resin having a carboxyl group or carboxylic acid anhydride structure (C) and imidazole silane compound (D) in the resin composition.

[0069] <Inorganic filler (E)> The resin composition of the present invention preferably contains an inorganic filler (E) from the viewpoint of the elongation of the resulting cured product and the conductivity of the resulting cured product in the initial stage, after soldering, after long-term reliability testing, and after thermal cycling testing, and more preferably contains an inorganic filler (E) and an organic filler (F) described later. In this specification, inorganic filler (E) refers to fillers made of metal or an alloy thereof, i.e., inorganic fillers other than the metal filler (G) described later.

[0070] There are no particular restrictions on the inorganic filler (E), but examples include non-conductive inorganic fillers such as calcium carbonate particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, talc particles, and silica particles, as well as conductive inorganic fillers such as carbon black particles. In particular, from the viewpoint of conductivity in the initial stage, after soldering, after long-term reliability testing, and after thermal cycling testing of the resulting cured product, at least one particle selected from the group consisting of talc particles and silica particles is preferred, and talc particles are more preferred.

[0071] The average particle size of the inorganic filler (E) is not particularly limited, but from the viewpoint of conductivity, coatability, and coat thickness adjustability of the resulting cured product in the initial stage, after soldering, after long-term reliability testing, and after thermal cycling testing, it is preferably 0.001 μm to 50 μm, more preferably 0.005 μm to 30 μm, and particularly preferably 0.01 μm to 10 μm. In this specification, the average particle diameter of the filler is the D50 average particle diameter obtained by measuring the filler using a laser diffraction / scattering particle size distribution analyzer LS 13320 (manufactured by Beckman Coulter) with a Tornado Dry Powder sample module, and the average particle diameter of the particle size distribution where the cumulative value of the particles is 50% is used.

[0072] The resin composition of the present invention may contain one inorganic filler (E) alone or two or more types, but from the viewpoint of conductivity in the initial stage, after soldering, after long-term reliability testing and after thermal cycling testing of the resulting cured product, it is preferable to contain two or more types, and more preferable to contain two types. The content of the inorganic filler (E) is preferably 0.1 to 50 parts by mass, more preferably 0.5 to 20 parts by mass, and particularly preferably 1 to 10 parts by mass, based on 100 parts by mass of the total amount of the polyester polyurethane resin (A), epoxy resin (B), resin having a carboxyl group or carboxylic acid anhydride structure (C) in the resin composition, and the imidazole silane compound (D) which may be included as an optional component.

[0073] <Organic Filler (F)> The resin composition of the present invention preferably contains an organic filler (F) from the viewpoint of the elongation, conductivity, and heat and humidity resistance of the resulting cured product. The organic filler (F) is usually mainly composed of resin and is non-conductive. Examples of organic fillers (F) include (meth)acrylic resin particles, polybutadiene particles, nylon fine particles, polyolefin particles, polyester particles, polycarbonate particles, polyvinyl alcohol particles, polyvinyl ether particles, polyvinyl butyral particles, silicone rubber particles, polyurethane particles, phenolic resin particles, and polytetrafluoroethylene particles. Organic fillers were found to enhance the compatibility of polyester polyurethane resin (A), epoxy resin (B), and resin having a carboxyl group or carboxylic acid anhydride structure (C) when dissolved in these resins. Furthermore, from the viewpoint of further improving the compatibility and liquid stability of these resins, silicone particles, polybutadiene particles, (meth)acrylic resin particles, or polyurethane particles are particularly preferred.

[0074] The average particle size of the organic filler (F) is not particularly limited, but from the viewpoint of coatability and coat thickness adjustment, it is preferably 0.5 μm to 50 μm, and more preferably 1 μm to 30 μm.

[0075] The resin composition of the present invention may contain one type of organic filler (F) alone, or it may contain two or more types. The content of the organic filler (F) is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, and particularly preferably 10 to 20 parts by mass, based on 100 parts by mass of the total amount of the polyester polyurethane resin (A), epoxy resin (B), resin having a carboxyl group or carboxylic acid anhydride structure (C) in the resin composition, and an imidazole silane compound (D) which may be included as an optional component.

[0076] <Metal filler (G)> The resin composition of the present invention preferably contains a metal filler (G) from the viewpoint of conductivity and heat resistance. The metal filler (G) is usually conductive. Preferably, the metal filler (G) is made of metal particles consisting of conductive metals or alloys thereof, such as gold, platinum, silver, copper, and nickel. From the viewpoint of cost reduction, particles in which a metal or resin is used as a core and the coating layer is formed of a highly conductive material are also preferred. The core is preferably made of at least one material selected from the group consisting of nickel, silica, copper, and resin, and more preferably made of a conductive metal or alloy thereof. The coating layer is preferably made of a material with excellent conductivity, and is preferably made of a conductive metal or a conductive polymer. Examples of conductive metals include gold, platinum, silver, tin, manganese, and indium, as well as their alloys. Examples of conductive polymers include polyaniline and polyacetylene. Among these, silver is preferred from the standpoint of conductivity.

[0077] From the viewpoint of cost and conductivity, the particle consisting of the nucleus and the coating layer preferably has a coating layer in a ratio of 1 to 40 parts by mass per 100 parts by mass of the nucleus, and more preferably has a coating layer in a ratio of 5 to 30 parts by mass.

[0078] The particle consisting of the core and the coating layer is preferably a particle in which the coating layer completely covers the core. However, in reality, a part of the core may be exposed. Even in such cases, conductivity is easily maintained if 70% or more of the surface area of ​​the core is covered by the conductive material.

[0079] The shape of the metal filler (G) is not limited as long as the desired conductivity is obtained. Specifically, for example, spherical, flake-shaped, leaf-shaped, dendritic, plate-shaped, needle-shaped, rod-shaped, or grape-shaped fillers are preferred.

[0080] The average particle size of the metal filler (G) is preferably 1 μm to 100 μm, more preferably 3 μm to 50 μm, and particularly preferably 4 μm to 15 μm, from the viewpoint of conductivity and storage stability. In addition to the method described above, the average particle diameter of the metal filler (G) can also be determined from the average value of approximately 20 randomly selected particles in an electron microscope magnified image (approximately 1,000x to 10,000x). In this case, the average particle diameter is preferably 1 μm to 100 μm, and more preferably 3 μm to 50 μm. If the metal filler (G) has a long axis and a short axis (for example, rod-shaped particles), the average particle diameter is calculated using the length along the long axis.

[0081] The resin composition of the present invention may contain one metal filler (G) alone or two or more metal fillers (G). The content of the metal filler (G) is preferably 1 to 500 parts by mass, more preferably 10 to 350 parts by mass, and particularly preferably 10 to 50 parts by mass, based on 100 parts by mass of the total amount of the polyester polyurethane resin (A), epoxy resin (B), and resin (C) having a carboxyl group or carboxylic acid anhydride structure in the resin composition, from the viewpoint of conductivity, heat resistance, and storage stability.

[0082] The resin composition of the present invention may contain other additives besides the components described above. Other additives that do not affect the function of the resin composition may include other thermoplastic resins, tackifiers, flame retardants, curing agents, curing accelerators, coupling agents, heat aging inhibitors, leveling agents, defoamers, and solvents, in amounts that do not affect the function of the resin composition.

[0083] Examples of the aforementioned other thermoplastic resins include phenoxy resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, polyacetal resins, polyethylene resins, polypropylene resins, and polyvinyl resins. These thermoplastic resins may be used individually or in combination of two or more.

[0084] Examples of the tackifiers include coumarone-indene resin, terpene resin, terpene-phenol resin, rosin resin, pt-butylphenol-acetylene resin, phenol-formaldehyde resin, xylene-formaldehyde resin, petroleum hydrocarbon resin, hydrogenated hydrocarbon resin, turpentine resin, and the like. These tackifiers may be used individually or in combination of two or more.

[0085] The aforementioned flame retardant may be either an organic flame retardant or an inorganic flame retardant. Examples of organic flame retardants include phosphorus-based flame retardants such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium phosphate, ammonium polyphosphate, carbamate phosphate, carbamate polyphosphate, aluminum tris-diethylphosphinate, aluminum tris-methylethylphosphinate, aluminum tris-diphenylphosphinate, zinc bis-diethylphosphinate, zinc bis-methylethylphosphinate, zinc bis-diphenylphosphinate, titanyl bis-diethylphosphinate, titanium tetrakis-diethylphosphinate, titanyl bis-methylethylphosphinate, titanium tetrakis-methylethylphosphinate, titanyl bis-diphenylphosphinate, and titanium tetrakis-diphenylphosphinate; nitrogen-based flame retardants such as triazine compounds like melamine, melam, and melamine cyanurate, as well as cyanuric acid compounds, isocyanuric acid compounds, triazole compounds, tetrazole compounds, diazo compounds, and urea; and silicon-based flame retardants such as silicone compounds and silane compounds. Furthermore, examples of inorganic flame retardants include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, and calcium hydroxide; metal oxides such as tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, and nickel oxide; and zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc borate, and hydrated glass. These flame retardants may be used individually or in combination of two or more types.

[0086] The curing agent is a component for forming a crosslinked structure through reaction with epoxy resin (B), and examples include amine-based curing agents such as aliphatic diamines, aliphatic polyamines, cyclic aliphatic diamines and aromatic diamines; polyamidoamine-based curing agents; acid-based curing agents such as aliphatic polycarboxylic acids, alicyclic polycarboxylic acids, aromatic polycarboxylic acids and their acid anhydrides; basic active hydrogen-based curing agents such as dicyandiamide and organic acid dihydrazides; polymercaptan-based curing agents; novolac resin-based curing agents; urea resin-based curing agents; melamine resin-based curing agents, etc. These hardening agents may be used individually or in combination of two or more types.

[0087] Examples of aliphatic diamine curing agents include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, polymethylenediamine, polyetherdiamine, 2,5-dimethylhexamethylenediamine, and trimethylhexamethylenediamine.

[0088] Examples of aliphatic polyamine-based curing agents include diethylenetriamine, iminobis(hexamethylene)triamine, trihexatetramine, tetraethylenepentamine, aminoethylethanolamine, tri(methylamino)hexane, dimethylaminopropylamine, diethylaminopropylamine, and methyliminobispropylamine.

[0089] Examples of cyclic aliphatic diamine curing agents include mensendiamine, isophoronediamine, bis(4-amino-3-methyldicyclohexyl)methane, diaminodicyclohexylmethane, bis(aminomethyl)cyclohexane, N-ethylaminopiperazine, 3,9-bis(3-aminopropyl)2,4,8,10-tetraoxaspiro[5.5]undecane, and hydrogenated metaxylylenediamine.

[0090] Examples of aromatic diamine curing agents include metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiethyldiphenylmethane, and metaxylylenediamine.

[0091] Examples of aliphatic polycarboxylic acid-based curing agents and acid anhydride-based curing agents include succinic acid, adipic acid, dodecenyl succinic anhydride, polyadipic anhydride, polyazelaic anhydride, and polysebacic anhydride.

[0092] Examples of alicyclic polycarboxylic acid-based curing agents and acid anhydride-based curing agents include methyltetrahydrophthalic acid, methylhexahydrophthalic acid, methylhymic acid, hexahydrophthalic acid, tetrahydrophthalic acid, trialkyltetrahydrophthalic acid, methylcyclodicarboxylic acid, and their acid anhydrides.

[0093] Examples of aromatic polycarboxylic acid-based curing agents and acid anhydride-based curing agents include phthalic acid, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid, ethylene glycol glycol bistrimellic acid, glycerol tristrimellic acid, and their acid anhydrides.

[0094] Examples of polymer mercaptan-based curing agents include mercapto-type epoxy resins and mercaptopropionate esters.

[0095] Examples of novolac-based curing agents include phenol novolac-based curing agents and cresol novolac-based curing agents.

[0096] When the resin composition of the present invention contains the curing agent, the content of the curing agent is set such that, from the viewpoint of adhesion and heat resistance, its functional group equivalent is preferably in the range of 0.2 to 2.5 molar equivalents, more preferably in the range of 0.4 to 2.0 molar equivalents, relative to 1 molar equivalent of epoxy groups of epoxy resin (B).

[0097] The curing accelerator is an ingredient used to accelerate the reaction of epoxy resin (B), and can be a tertiary amine-based curing accelerator, a tertiary amine salt-based curing accelerator, or an imidazole-based curing accelerator. These curing accelerators may be used individually or in combination of two or more types.

[0098] Examples of tertiary amine-based curing accelerators include benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, tetramethylguanidine, triethanolamine, N,N'-dimethylpiperazine, triethylenediamine, and 1,8-diazabicyclo[5.4.0]undecene.

[0099] Examples of tertiary amine salt-based curing accelerators include formate, octylate, p-toluenesulfonate, o-phthalate, phenol salt, or phenol novolac resin salt of 1,8-diazabicyclo[5.4.0]undecene, and formate, octylate, p-toluenesulfonate, o-phthalate, phenol salt, or phenol novolac resin salt of 1,5-diazabicyclo[4.3.0]nonene.

[0100] Imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-methyl-4-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'- Examples include undecylimidazolyl-(1')-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanurate adduct, 2-phenylimidazole isocyanurate adduct, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0101] If the resin composition of the present invention contains a curing accelerator, the amount of the curing accelerator is preferably in the range of 1 to 10 parts by mass, and particularly preferably in the range of 2 to 5 parts by mass, per 100 parts by mass of epoxy resin (B), from the viewpoint of adhesion and heat resistance.

[0102] Furthermore, examples of coupling agents include silane-based 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-isocyanatetopropyltriethoxysilane, and imidazolesilane; titanate-based coupling agents; aluminate-based coupling agents; and zirconium-based coupling agents. These may be used individually or in combination of two or more.

[0103] Examples of the aforementioned heat aging inhibitors include phenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, and tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane; sulfur-based antioxidants such as dilauryl-3,3'-thiodipropionate and dimyristyl-3,3'-dithiopropionate; and phosphorus-based antioxidants such as trisnonylphenyl phosphite and tris(2,4-di-tert-butylphenyl)phosphite. These may be used individually or in combination of two or more.

[0104] The resin composition of the present invention can be prepared by mixing a polyester polyurethane resin (A), an epoxy resin (B), and, if necessary, other components. Since the resin composition of the present invention is preferably used in solution or dispersion form, it is preferable that it contains a solvent. Examples of solvents include alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutyl alcohol, n-butyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diacetone alcohol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and isophorone; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and mesitylene; esters such as methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; and aliphatic hydrocarbons such as hexane, heptane, cyclohexane, and methylcyclohexane. These solvents may be used individually or in combination of two or more. When the resin composition of the present invention is a solution or dispersion containing a solvent, coating onto the substrate and forming a resin composition layer can be performed smoothly, and a resin composition layer of the desired thickness can be easily obtained.

[0105] When the resin composition of the present invention contains a solvent, the solvent is used such that, from the viewpoint of workability including film-forming properties, the solid content concentration is preferably in the range of 3% to 80% by mass, more preferably 10% to 50% by mass.

[0106] Suitable adherends for the resin composition of the present invention are polymer materials such as polyimide resin, polyetheretherketone resin, polyphenylene sulfide resin, aramid resin, and liquid crystal polymer; and objects made of metallic materials such as copper, aluminum, and stainless steel. The shape of the adherend is not particularly limited. Furthermore, a composite product can be manufactured by bonding two members made of the same or different materials together using the resin composition of the present invention. In addition, products having an adhesive resin composition layer, such as the coverlay film and bonding sheet described below, can be manufactured.

[0107] (Laminate with resin composition layer, and laminate) The laminate with a resin composition layer of the present invention is a laminate using the resin composition of the present invention, and preferably comprises a resin composition layer made of the resin composition of the present invention, a B-stage resin composition layer obtained by partially curing the resin composition, or a cured layer obtained by curing the resin composition, and a base film in contact with at least one surface of the resin composition layer, the B-stage resin composition layer, or the cured layer. In the present invention, the resin composition layer being in a B-stage state refers to a semi-cured state in which a part of the resin composition layer has begun to harden, and further hardening of the resin composition layer progresses due to heating or the like. Furthermore, when using a resin composition containing a solvent, the resin composition layer comprising the resin composition of the present invention is preferably a layer obtained by removing at least a portion of the solvent from the resin composition of the present invention.

[0108] The laminate with a resin composition layer of the present invention and the laminate of the present invention preferably have a substrate, and more preferably have a layer made of the resin composition of the present invention on the substrate. There are no particular restrictions on the substrate material; known substrate materials can be used. Furthermore, the base material is preferably a film-like base material (base film). The base film is preferably a resin film, more preferably a polyimide film or an aramid film, and particularly preferably a polyimide film. The polyimide film or aramid film is not particularly limited as long as it has electrical insulating properties, and can be a film made solely of polyimide resin or aramid resin, a film containing the resin and additives, etc., and the side on which the resin composition layer is formed may be surface-treated. The thickness of the substrate is not particularly limited, but is preferably 3 μm to 125 μm. Furthermore, the thickness of the resin composition layer is preferably 5 μm to 50 μm, and more preferably 10 μm to 40 μm.

[0109] As a method for producing a laminate with a resin composition layer of the present invention, for example, a resin composition of the present invention containing a solvent can be applied to the surface of a base film such as a polyimide film to form a resin composition layer, and then at least a portion of the solvent can be removed from the resin composition layer to produce a laminate having a B-stage resin composition layer. The drying temperature when removing the solvent is preferably 40°C to 250°C, and more preferably 70°C to 170°C. Drying is performed by passing the laminate coated with the resin composition through a furnace that is subjected to hot air drying, far-infrared heating, and high-frequency induction heating, etc. The laminate with a resin composition layer of the present invention may optionally further have a release film on the surface of the resin composition layer for storage or other purposes. As the release film, known films such as polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release treated paper, polyolefin resin coated paper, polymethylpentene (TPX) film, and fluororesin film can be used.

[0110] The thickness of the B-stage resin composition layer is preferably 5 μm to 100 μm, more preferably 5 μm to 70 μm, even more preferably 5 μm to 50 μm, and particularly preferably 10 μm to 40 μm. The thickness of the base film and resin composition layer is selected according to the application, but the base film tends to become thinner in order to improve electrical properties. The preferred thickness of the base film is the same as the preferred thickness of the base material described above. In the laminate with a resin composition layer of the present invention, the ratio (A / B) of the thickness of the resin composition layer (A) to the thickness of the base film (B) is preferably 1 or more and 10 or less, and more preferably 1 or more and 5 or less. Furthermore, it is preferable that the thickness of the resin composition layer is greater than the thickness of the base film.

[0111] A preferred method for manufacturing the laminate of the present invention is to first coat the surface of a base film with the resin composition of the present invention containing a solvent, then dry it in the same manner as in the case of a laminate with a resin composition layer of the present invention, then bring the surface of the formed resin composition layer into surface contact with the adherend and perform lamination, for example, heat lamination at 80°C to 150°C. Next, heat-press the laminate (base film / resin composition layer / adherend) and further cure the resin composition layer by after-curing to form a cured layer. The conditions for heat bonding are not particularly limited as long as bonding is possible, but preferably they can be 150°C to 200°C and 1 MPa to 3 MPa for 1 to 60 minutes. The conditions for after-curing are not particularly limited, but preferably they can be 100°C to 200°C for 30 minutes to 4 hours. The thickness of the cured layer is preferably 5 μm to 100 μm, more preferably 5 μm to 70 μm, even more preferably 5 μm to 50 μm, and particularly preferably 10 μm to 40 μm. There are no particular restrictions on the adherend, and the aforementioned examples are included. Among these, a metal adherend is preferred, copper foil or plated copper foil is more preferred, and gold-plated copper foil is particularly preferred. Furthermore, there are no particular restrictions on the shape and size of the object to be adhered to; publicly known shapes and sizes can be used.

[0112] Furthermore, one embodiment of the laminate of the present invention is a flexible copper-clad laminate. In other words, the flexible copper-clad laminate of the present invention preferably has a cured layer obtained by curing a resin composition made of the resin composition of the present invention, and preferably has a polyimide film or aramid film, a cured layer obtained by curing the resin composition of the present invention, and copper foil laminated together. In the flexible copper-clad laminate of the invention, the cured layer and the copper foil may be formed on both sides of a polyimide film or an aramid film. Since the resin composition of the present invention has excellent adhesion to articles containing copper, the flexible copper-clad laminate of the present invention has excellent stability as an integrated product.

[0113] The structure of the polyimide film or aramid film is the same as that of the polyimide film or aramid film in the coverlay film of the present invention described above. The thickness of the hardened layer is preferably 5 μm to 50 μm, and more preferably 10 μm to 40 μm. Furthermore, the copper foil is not particularly limited, and electrolytic copper foil, rolled copper foil, etc., can be used. Furthermore, the copper foil may be plated with a known metal or alloy such as gold or silver.

[0114] One embodiment of the resin composition layer-equipped laminate of the present invention includes bonding films, electromagnetic shielding films, coverlay films, and the like, as described later.

[0115] -Bonding film- The bonding film of the present invention uses the resin composition of the present invention, and preferably comprises a B-stage resin composition layer obtained by partially curing the resin composition of the present invention, and a release film in contact with at least one surface of the resin composition layer. Furthermore, the bonding film of the present invention is also an embodiment of the laminate with a resin composition layer of the present invention, which will be described later. Furthermore, the bonding film of the present invention may also be configured to include a resin composition layer between two release films. As the release film, one of the known types described above can be used. The thickness of the release film is preferably 20 μm to 100 μm. Furthermore, the thickness of the resin composition layer is preferably 5 μm to 100 μm, and more preferably 10 μm to 60 μm.

[0116] A preferred method for manufacturing the bonding sheet of the present invention is, for example, to coat the surface of a release film with the resin composition of the present invention containing a solvent, and then dry it in the same manner as described above for the laminate with the resin composition layer of the present invention.

[0117] -Electromagnetic wave shielding film- The electromagnetic wave shielding film of the present invention uses the resin composition of the present invention, and preferably has a resin composition layer made of the resin composition of the present invention, a B-stage resin composition layer obtained by partially curing the resin composition, or a cured layer obtained by curing the resin composition. Furthermore, it is preferable that the electromagnetic wave shielding film of the present invention has the resin composition layer and the protective layer. The protective layer is not particularly limited as long as it is made of an insulating resin composition, and any known composition can be used. Furthermore, the protective layer may use the resin components used in the resin composition of the present invention. In addition, the protective layer may be formed from two or more layers with different compositions and hardnesses. Furthermore, the protective layer may contain, as needed, curing accelerators, tackifiers, antioxidants, pigments, dyes, plasticizers, UV absorbers, defoamers, leveling agents, fillers, flame retardants, viscosity modifiers, anti-blocking agents, etc.

[0118] The thickness of the resin composition layer in the electromagnetic wave shielding film of the present invention is not particularly limited, but it is preferably 3 μm to 30 μm from the viewpoint of conductivity and connectivity with the ground circuit.

[0119] Next, a specific embodiment of the method for manufacturing the electromagnetic wave shielding film of the present invention will be described. For example, one method involves coating and drying a protective layer resin composition on one side of a release film to form a protective layer, and then coating and drying the resin composition of the present invention on the protective layer to form a resin composition layer. By the manufacturing method described above, an electromagnetic wave shielding film can be obtained in a laminated state consisting of a resin composition layer, a protective layer, and a release film.

[0120] The resin composition layer and protective layer can be provided by conventionally known coating methods, such as gravure coating, kiss coating, die coating, lip coating, comma coating, blade coating, roll coating, knife coating, spray coating, bar coating, spin coating, dip coating, etc.

[0121] The electromagnetic shielding film of the present invention can be bonded to a printed circuit board, for example, by heat pressing. The resin composition layer softens upon heating and flows into the ground portion provided on the printed circuit board under pressure. This electrically connects the ground circuit and the conductive adhesive, thereby enhancing the shielding effect. [Examples]

[0122] The present invention will be described in detail below based on the following examples. However, the present invention is not limited to these examples. In the following, "parts" and "%" mean "parts by mass" and "% by mass," respectively, unless otherwise specified.

[0123] <<Ingredients Used>> 1. Polyester polyurethane resin (A) Commercially available and synthetic polyesters were used as the polyester in the manufacture of polyester polyurethane.

[0124] <Commercially available product> The commercially available products used were Aronmelt PES-360HVXM30 and Aronmelt PES-310S30, both manufactured by Toagosei Co., Ltd. PES-360HVXM30 had a number-average molecular weight of 20,000 and a glass transition temperature of 65°C. PES-310S30 also had a number-average molecular weight of 20,000 and a glass transition temperature of 8°C.

[0125] <Synthesis of polyester resin (PES-1)> In a flask equipped with a stirrer, nitrogen inlet tube, distillation tube, and thermometer, 201 parts by mass of dimethyl terephthalate, 86 parts by mass of ethylene glycol, 140 parts by mass of neopentyl glycol, 0.9 parts by mass of trimethylolpropane, and 0.22 parts by mass of zinc acetate as a catalyst were charged. The mixture was heated while introducing nitrogen, and methanol was distilled off at 150°C to 180°C. Then, 183 parts by mass of isophthalic acid, 0.6 parts by mass of trimethylolpropane, and 0.12 parts by mass of antimony trioxide were added, and water was distilled off at 180°C to 210°C. Subsequently, the reaction was continued for 6 hours at 230°C under reduced pressure of 200 Pa, while gradually reducing the pressure. The resulting polyester resin PES-1 had a number-average molecular weight of 7,000 and a glass transition temperature of 60°C. Nuclear magnetic resonance (NMR) analysis revealed that the monomer composition, in molar ratio, was terephthalic acid / isophthalic acid / ethylene glycol / neopentyl glycol = 48 / 52 / 43 / 56. 180 parts by mass of the synthesized polyester resin was taken, and 378 parts by mass of toluene and 42 parts by mass of methyl isobutyl ketone were added to prepare a polyester solution.

[0126] <Synthesis of polyester polyurethane resin a1> (1) Synthesis of polyester polyurethane resin a1 In a flask equipped with a stirrer, reflux dehydrator, and distillation tube, 600 parts by mass of PES-360HVXM30, 100 parts by mass of toluene, and 30 parts by mass of 2-butyl-2-ethyl-1,3-propanediol were charged. The temperature was raised to 120°C and 100 parts by mass of the solvent containing water was distilled off. Then the temperature was lowered to 105°C, and 0.4 parts by mass of 2,2-bis(hydroxymethyl)propionic acid was charged and dissolved. Subsequently, 42 parts by mass of Cosmonate NBDI (NBDI) manufactured by Mitsui Chemicals, Inc. were added, and after 30 minutes, 0.2 parts by mass of dibutyltin dilaurate was added. The reaction was continued until the desired molecular weight was reached, and then the solution of polyester urethane resin a1 was obtained by diluting with toluene / 2-propanol to adjust the solid content concentration to 30%. At that time, the number average molecular weight was 35,000, and the acid value was 2 mgKOH / g.

[0127] <Synthesis of polyester polyurethane resins a2-a12> Regarding the synthesis method of polyester polyurethane resin a1, the synthesis was carried out in the same manner as the synthesis method of polyester polyurethane resin a1, except that the polyester, diol, and diisocyanate shown in Table 1 were changed to the parts by mass shown in the table.

[0128] [Table 1]

[0129] The abbreviations listed in Table 1, other than those mentioned above, are explained below. Takenate 600: 1,3-bis(isocyanatomethyl)cyclohexane, manufactured by Mitsui Chemicals, Inc. HDMI: Methylenebis(4-cyclohexyl diisocyanate), manufactured by Wannate Chemical Japan Co., Ltd., product name WANNATE® HDMI HDI: Hexamethylene diisocyanate, manufactured by Tosoh Corporation, product name HDI Dimerol: A 36-carbon diol obtained by reducing dimer acid, manufactured by Croda Japan Co., Ltd., product name PRIPOL2033.

[0130] 2. Epoxy resin (B) The following commercially available products were used. (1) Epoxy resin b1 DIC Corporation's bisphenol A novolac type epoxy resin "EPICLON N-865" (product name) (2) Epoxy resin b2 Mitsubishi Chemical Corporation's bisphenol A type epoxy resin "jER 1055" (product name)

[0131] 3. Resins having a carboxyl group or carboxylic acid anhydride structure (C) (1) Synthesis of polyamide resin c1 Polyamide resin c1 was synthesized as follows. A flask equipped with a stirrer, reflux dehydrator, and distillation tube was charged with 65 parts by mass of azelaic acid, 190 parts by mass of dodecanedioic acid, 100 parts by mass of piperazine, and 120 parts by mass of distilled water. The temperature was raised to 120°C to distill off the water, and then the temperature was raised to 240°C at a rate of 20°C / hour, and the reaction was continued for 3 hours to obtain polyamide resin c1. The amine value of this resin was 4.5 mg KOH / g, and the acid value was 10.5 mg KOH / g.

[0132] (2) Synthesis of polyamide resin c2 Polyamide resin c2 was synthesized as follows. A flask equipped with a stirrer, reflux dehydrator, and distillation tube was charged with 485 parts by mass of dimer acid, 100 parts by mass of hexamethylenediamine, and 120 parts by mass of distilled water. The temperature was raised to 120°C to distill off the water, and then the temperature was raised to 240°C at a rate of 20°C / hour, and the reaction was continued for 3 hours to obtain polyamide resin c2. The amine value of this resin was 4.5 mg KOH / g, and the acid value was 10.5 mg KOH / g.

[0133] (3) Synthesis of polyolefin resin c3 100 parts by mass of a propylene-butene random copolymer consisting of 80% by mass of propylene units and 20% by mass of butene units, prepared using a metallocene catalyst as a polymerization catalyst, 1 part by mass of maleic anhydride, 0.3 parts by mass of lauryl methacrylate, and 0.4 parts by mass of di-t-butyl peroxide were mixed using a twin-screw extruder with the maximum cylinder temperature set to 170°C. Subsequently, degassing was performed under reduced pressure in the extruder to remove residual unreacted material, thereby producing polyolefin resin c1. Polyolefin resin c1 had a weight-average molecular weight of 80,000 and an acid value of 10 mgKOH / g. The graft content in polyolefin resin c1 was 1.5% by mass.

[0134] (4) Synthesis of polyolefin resin c4 (resin without carboxyl groups and carboxylic acid anhydride structures) Using a metallocene catalyst as a polymerization catalyst, 80% by mass of propylene units and 20% by mass of butene units were reacted to obtain polyolefin resin c4. Polyolefin resin c4 had a weight-average molecular weight of 100,000.

[0135] 4. Imidazole silane compounds (D) 1-(2-hydroxy-3-trimethoxysilylpropoxypropyl)imidazole

[0136] 5. Inorganic filler (E) (1) Inorganic filler e1 Talc "SG-95" manufactured by Nippon Talc Co., Ltd. (product name; average particle size 2.5 μm) (2) Inorganic filler e2 Aerosil "R972" (product name; average particle size 16nm, silica particles), obtained from Toshin Kasei Co., Ltd.

[0137] 6. Organic filler (F) (1) Organic filler f1 Urethane beads "TK-800T" manufactured by Negami Kogyo Co., Ltd. (product name; average particle size 8μm) (2) Organic filler f2 Acrylic beads “J-4P” manufactured by Negami Kogyo Co., Ltd. (product name; average particle size 2.2 μm)

[0138] 7. Metal filler (G) Copper powder "FCC-115A" manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd. (Product name; in terms of particle size distribution, particles 45 μm or smaller account for more than 90% by mass, particles between 45 μm and 63 μm account for less than 10% by mass, and particles between 63 μm and 75 μm account for less than 3% by mass.)

[0139] 8. Flame retardant Clariant's phosphinate metal salt "Exolit OP935" (product name)

[0140] 9. Curing accelerator Shikoku Chemicals Co., Ltd.'s imidazole-based curing accelerator "Curezol C11-Z" (product name)

[0141] 10. Solvent A mixed solvent consisting of toluene, methyl isobutyl ketone, and 2-propanol (mass ratio = 100:20:20)

[0142] (Examples 1-29 and Comparative Example 1) Liquid adhesive compositions were prepared by adding the above raw materials to a flask equipped with a stirring device in the proportions shown in Table 2, stirring at 60°C for 6 hours to dissolve components (A), (B), (C), imidazolesilane compound, and curing accelerator in the solvent, and dispersing inorganic fillers, organic fillers, metal fillers, and flame retardants. Subsequently, coverlay films, bonding sheets, and adhesion test pieces A and B were prepared using all of these liquid adhesive compositions, and evaluations (i) to (ix) below were performed. The evaluation results are shown in Table 2.

[0143] (1) Preparation of coverlay film A liquid adhesive composition was roll-coated onto the surface of a 25 μm thick polyimide film to a thickness of 15 μm after drying, and dried at 120°C for 2 minutes to obtain a coverlay film having an adhesive layer.

[0144] (2) Preparation of adhesive test piece A A 35 μm thick rolled copper foil manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd. was prepared. The mirror surface was then placed in contact with the adhesive layer surface of the coverlay film, and lamination was performed under the conditions of 150°C, 0.3 MPa, and 1 m / min. The resulting laminate (polyimide film / adhesive layer / copper foil) was heated and pressed at 150°C and 3 MPa for 5 minutes, and then after-cured in an oven at 160°C for 2 hours to obtain adhesive test piece A.

[0145] (3) Preparation of bonding sheets A 35 μm thick release-type PET film was prepared. A mixture of a liquid adhesive composition and copper powder "FCC-115A" manufactured by Fukuda Metal Foil & Powder Industry Co., Ltd., blended to make up 15% by mass of the total solid resin content, was roll-coated onto its surface to a thickness of 25 μm after drying, and dried at 140°C for 2 minutes to obtain a bonding sheet with an adhesive layer.

[0146] (4) Preparation of adhesive test piece B A flexible printed circuit board was prepared, consisting of a 300 μm thick nickel-plated SUS304 plate and a 25 μm thick polyimide film with a copper circuit pattern formed on its surface, and a 37.5 μm thick coverlay film with 1 mm diameter through-holes laminated on the circuit pattern. First, the nickel-plated surface of the SUS304 plate was placed in contact with the adhesive layer surface of the bonding sheet, and lamination was performed at 150°C, 0.3 MPa, and 1 m / min to obtain a laminate (SUS plate / adhesive layer / release PET film). Subsequently, the release PET film was peeled off, and the exposed adhesive layer was heated and pressed onto a flexible printed circuit board (a circuit board in which copper foil circuits are formed on a 25 μm thick polyimide, and a 37.5 μm thick coverlay film with a diameter of 1 mm through-holes is laminated on the copper foil circuits) at 150°C and 3 MPa for 5 minutes. After that, an after-curing was performed in an oven at 160°C for 2 hours to prepare adhesive test piece B (SUS plate / adhesive layer / flexible printed circuit board).

[0147] (i) Peel bond strength To evaluate adhesion, the 180° peel adhesion strength (N / mm) was measured when peeling the copper foil of each adhesive test piece A from the polyimide film, in accordance with JIS C 6481 "Test Method for Copper-Clad Laminates for Printed Wiring Boards," under conditions of a temperature of 23°C and a tensile speed of 50 mm / min. The width of the adhesive test piece during measurement was 10 mm. As a result, samples with a peel strength of 0.5 N / mm or higher were indicated as "A," samples with a peel strength of 0.35 N / mm or higher but less than 0.5 N / mm were indicated as "B," and samples with a peel strength of less than 0.35 N / mm were indicated as "C."

[0148] (ii) Peel adhesion strength after long-term moist heat test To evaluate the adhesion after storage at 85°C and 85%RH for 1,000 hours, the 180° peel adhesion strength (N / mm) was measured when peeling the copper foil of each adhesive test piece A from the polyimide film, in accordance with JIS C 6481 "Test Method for Copper-Clad Laminates for Printed Wiring Boards," under conditions of 23°C and a tensile speed of 50 mm / min. The width of the adhesive test piece during measurement was 10 mm. As a result, samples with a peel strength reduction rate of less than 15% compared to the initial value were indicated as "A," those with a reduction rate of 15% or more but less than 30% were indicated as "B," those with a reduction rate of 30% or more but less than 50% were indicated as "C," and those with a reduction rate of 50% or more were indicated as "D."

[0149] (iii) Solder heat resistance (appearance when soldering, peel adhesion strength after soldering) The tests were conducted in accordance with JIS C 6481 (1996) under the following conditions. With the polyimide film side facing up, the adhesive test piece A was floated in a 260°C solder bath for 60 seconds, and the presence or absence of appearance abnormalities such as blistering or peeling of the adhesive layer was visually evaluated. As a result, those in which no appearance abnormalities such as microvoids, blistering, or peeling were observed were indicated as "A", those in which only a few microvoids were observed were indicated as "B", and those in which appearance abnormalities such as blistering or peeling were observed were indicated as "C". Furthermore, the 180° peel adhesion strength (N / cm) of the polyimide film when peeling it from the gold-plated copper foil was measured at 23°C in accordance with JIS C 6481 for test specimens removed from the solder bath. The width of the adhesion test specimen during measurement was 10 mm, and the tensile speed was 50 mm / min. The width of the adhesion test specimen during measurement was 10 mm. As a result, specimens with a peel strength reduction rate of less than 15% compared to the initial value were indicated as "A", those with a reduction rate of 15% or more but less than 30% were indicated as "B", those with a reduction rate of 30% or more but less than 50% were indicated as "C", and those with a reduction rate of 50% or more were indicated as "D".

[0150] (iv) Flame retardant The coverlay film was heat-cured at 160°C for 2 hours, and its flame retardancy was evaluated in accordance with UL-94 as defined by Undewriters Laboratories. Products that passed the test (VTM-0 class) were marked "A," and those that failed were marked "F."

[0151] (v) Conductivity (initial, connection resistance) The connection resistance between the SUS plate and the copper foil circuit of the flexible printed circuit board in the above-mentioned adhesive test piece B (SUS plate / adhesive layer / flexible printed circuit board) was measured using a resistance meter. As a result, those with a connection resistance of less than 0.3Ω were indicated as "A", those with a connection resistance of 0.3Ω or more and less than 0.5Ω were indicated as "B", those with a connection resistance of 0.5Ω or more and 1Ω or less were indicated as "C", those with a connection resistance of 1Ω or more and 3Ω or less were indicated as "D", and those with a connection resistance exceeding 3Ω were indicated as "E".

[0152] (vi) Conductivity after soldering (conductivity after soldering, connection resistance) The above adhesive test piece B was floated in a 260°C solder bath for 60 seconds. After removing the adhesive test piece B from the solder bath, the connection resistance between the SUS plate and the copper foil circuit of the flexible printed circuit board was measured using a resistance meter. As a result, those with a connection resistance of less than 0.3Ω were designated as "A", those with a connection resistance of 0.3Ω or more and less than 0.5Ω were designated as "B", those with a connection resistance of 0.5Ω or more and 1Ω or less were designated as "C", those with a connection resistance of 1Ω or more and 3Ω or less were designated as "D", and those with a connection resistance exceeding 3Ω were designated as "E".

[0153] (vii) Conductivity after long-term reliability testing (conductivity and connection resistance after 1,000 hours of storage at 85°C and 85% RH) The above adhesive test piece B was left in a constant temperature and humidity chamber at 85°C and 85%RH for 1,000 hours. After that, the connection resistance between the SUS plate of adhesive test piece B and the copper foil circuit of the flexible printed circuit board was measured using a resistance meter. As a result, those with a connection resistance of less than 0.3Ω were designated as "A", those with a connection resistance of 0.3Ω or more and less than 0.5Ω were designated as "B", those with a connection resistance of 0.5Ω or more and 1Ω or less were designated as "C", those with a connection resistance of 1Ω or more and 3Ω or less were designated as "D", and those with a connection resistance exceeding 3Ω were designated as "E".

[0154] (viii) Conductivity (connection resistance) after thermal cycling test The above adhesive test piece B was placed in a thermal shock tester that operated at high temperature (125°C) and low temperature (-40°C). After holding it at -40°C for 30 minutes and then at 125°C for 30 minutes, a thermal cycle was performed for 1,000 cycles, with one cycle being defined as one thermal cycle. The connection resistance between the SUS plate of adhesive test piece B and the copper foil circuit of the flexible printed circuit board was then measured using a resistance meter. As a result, specimens with a connection resistance of less than 0.3Ω were designated as "A", those with a connection resistance of 0.3Ω or more and less than 0.5Ω were designated as "B", those with a connection resistance of 0.5Ω or more and 1Ω or less were designated as "C", those with a connection resistance of 1Ω or more and 3Ω or less were designated as "D", and those with a connection resistance exceeding 3Ω were designated as "E".

[0155] (ix) Storage stability of resin composition The adhesive compositions (resin compositions) of Examples 1 to 29 and Comparative Example 1, having the compositions listed in Table 1, were each placed in glass bottles, sealed, and stored at 5°C for a predetermined time. The crystallinity of the compositions was then observed. After storage for the predetermined time, any gelation or liquid separation of the adhesive composition was considered to indicate poor storage stability, and an evaluation was performed accordingly. <Evaluation Criteria> A: No gelation or liquid separation was observed for more than one week. F: Gelation or liquid separation occurred in less than one week.

[0156] [Table 2]

[0157] Note that the units of the numerical values ​​in the component column of the resin composition listed in Table 2 are parts by mass.

[0158] As is clear from the results shown in Table 2 above, the resin compositions of Examples 1 to 29 were resin compositions in which the cured products obtained were superior in conductivity compared to the resin composition of Comparative Example 1, regardless of whether the test was after long-term storage in a high-temperature, high-humidity environment or after a thermal cycling test. Furthermore, the resin compositions of Examples 1 to 29 produced cured products that exhibited excellent initial peel adhesion strength, peel adhesion strength after soldering, peel adhesion strength after long-term reliability testing, flame retardancy, initial conductivity, and conductivity after soldering.

[0159] The disclosure of Japanese Patent Application No. 2020-178234, filed on 23 October 2020, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. Polyester polyurethane resin (A), It contains epoxy resin (B), The diisocyanate component constituting the polyester polyurethane resin (A) includes a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms. The diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms has an alicyclic structure, It further contains organic filler (F), The organic filler (F) is a non-conductive resin filler, It further contains a metal filler (G), The metal filler (G) is a conductive filler, It contains a resin (C) having a carboxyl group or a carboxylic acid anhydride structure as an optional component, A resin composition in which the content of the metal filler (G) is 10 to 50 parts by mass per 100 parts by mass of the total amount of the polyester polyurethane resin (A), the epoxy resin (B), and the optional component resin (C) having a carboxyl group or carboxylic acid anhydride structure.

2. The resin composition according to claim 1, further comprising a resin (C) having a carboxyl group or a carboxylic acid anhydride structure.

3. The resin composition according to claim 1 or claim 2, wherein the molecular weight per urethane bond in the polyester polyurethane resin (A) is 200 to 8,000.

4. The resin composition according to any one of claims 1 to 3, wherein the content of polyester polyurethane resin (A) is 10% to 90% by mass and the content of resin having a carboxyl group or carboxylic acid anhydride structure (C) is 5% to 70% by mass, based on the total amount of polyester polyurethane resin (A), epoxy resin (B), resin having a carboxyl group or carboxylic acid anhydride structure (C), and imidazole silane compound (D) which may be contained as an optional component.

5. The resin composition according to any one of claims 1 to 4, further comprising an inorganic filler (E).

6. The resin composition according to any one of claims 1 to 5, wherein the diol component constituting the polyester polyurethane resin (A) comprises a diol compound having a hydrocarbon group with 5 to 32 carbon atoms.

7. The resin composition according to claim 6, wherein the diol compound having a hydrocarbon group having 5 to 32 carbon atoms comprises a diol compound having an alicyclic structure or two or more side chains.

8. The resin composition according to any one of claims 1 to 7, wherein the polyester polyurethane resin (A) comprises a polyester polyurethane resin having a polyester structure with a number average molecular weight of 8,000 to 30,000.

9. The resin composition according to any one of claims 1 to 8, wherein the number average molecular weight of the polyester polyurethane resin (A) is 10,000 to 80,000.

10. The resin composition according to any one of claims 1 to 9, wherein the acid value of the polyester polyurethane resin (A) is 0.1 mg KOH / g to 20 mg KOH / g.

11. The resin composition according to any one of claims 1 to 10, wherein the glass transition temperature of the polyester polyurethane resin (A) is 30°C to 150°C.

12. The resin composition according to any one of claims 1 to 11, wherein the content of epoxy resin (B) is 1 to 30 parts by mass per 100 parts by mass of polyester polyurethane resin (A).

13. The resin composition according to any one of claims 1 to 12, wherein the epoxy resin (B) comprises a bisphenol A type epoxy resin and / or a novolac type epoxy resin.

14. The resin composition according to any one of claims 1 to 13, wherein the content of the resin (C) having a carboxyl group or a carboxylic acid anhydride structure is 1 to 100 parts by mass per 100 parts by mass of the polyester polyurethane resin (A).

15. The resin composition according to any one of claims 1 to 14, wherein the resin (C) having a carboxyl group or a carboxylic acid anhydride structure comprises at least one of a polyamide resin having an acid value and a resin having an acid-modified polyolefin structure.

16. A bonding film comprising a B-stage resin composition layer obtained by partially curing the resin composition according to any one of claims 1 to 15, and a release film in contact with at least one surface of the resin composition layer.

17. A laminate with a resin composition layer comprising a resin composition layer made of the resin composition according to any one of claims 1 to 15, a B-stage resin composition layer obtained by partially curing the resin composition, or a cured layer obtained by curing the resin composition, and a base film in contact with at least one surface of the resin composition layer, the B-stage resin composition layer, or the cured layer.

18. A laminate comprising a cured layer obtained by curing the resin composition according to any one of claims 1 to 15.

19. A flexible copper-clad laminate comprising copper foil, a cured layer obtained by curing a resin composition according to any one of claims 1 to 15, and a substrate.

20. A flexible flat cable comprising copper wiring, a cured layer obtained by curing a resin composition according to any one of claims 1 to 15, and a covering material.

21. An electromagnetic wave shielding film having a resin composition layer made of the resin composition according to any one of claims 1 to 15, a B-stage resin composition layer obtained by partially curing the resin composition, or a cured layer obtained by curing the resin composition.

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