Thermosetting adhesive sheets and their cured products, thermosetting cover sheets with release films, copper-clad laminates, printed wiring boards, and electronic devices

Abstract

An object of the present invention is to provide a thermosetting resin composition that exhibits little resin flow during a heat press process and that can form a cured product after curing that has excellent laser processability, heat resistance, thermal cycle resistance, and impact absorption properties. [Solution] A thermosetting resin composition comprising a polyimide resin (A) which is a reaction product of a group of monomers including a dimer diamine (a-1) and a tetracarboxylic acid anhydride (a-2), at least one curing agent (B) selected from the group consisting of an epoxy compound (B-1), a maleimide compound (B-2), an isocyanate group-containing compound (B-3), a metal chelate compound (B-4) and a carbodiimide group-containing compound (B-5), and a filler (C), wherein the cured product obtained by heating the thermosetting resin composition at 180°C for 60 minutes exhibits a specific storage modulus at a predetermined temperature.

Description

[Technical Field]

[0001] The present invention relates to a thermosetting resin composition containing a polyimide resin and a cured product thereof. The thermosetting adhesive sheet and the thermosetting cover sheet with a release film formed from the thermosetting resin composition of the present invention are suitable for use in the production of copper-clad laminates and the protection of the circuit surface of printed wiring boards. [Background technology]

[0002] In recent years, with the progress of higher density and higher functionality in electronic devices, there is a demand for materials used in printed wiring boards to have better dimensional stability and excellent high frequency characteristics. For example, Patent Document 1 discloses a multilayer circuit board having an adhesive layer in a metal-clad laminate, in which the storage modulus at 50°C is 1800 MPa, the maximum storage modulus in the temperature range from 180°C to 260°C is 800 MPa or less, and the glass transition temperature (Tg) is 180°C or less, thereby providing excellent dimensional stability of the conductor and enabling reduced transmission loss even in the transmission of high-frequency signals. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-72198 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, with the miniaturization of electronic devices, communication devices, and the like, the materials used in the printed wiring boards are required to have not only dimensional stability and reduced transmission loss, but also high processability such as via formation and various high levels of reliability.

[0005] To ensure electrical continuity between inner and outer layer circuits on printed wiring boards, openings such as blind vias and through holes are often created using laser processing or drilling, and processability for forming these openings is crucial. New concepts in space saving and circuit design require materials that can be processed with smaller hole diameters. Furthermore, materials must be resistant to processing solutions used to remove the residue known as smear that results from processing.

[0006] Furthermore, in recent years, from the perspective of environmental protection, there has been an increasing demand for the use of lead-free solder instead of conventional lead-containing solder. Because lead-free solder has a higher melting point than conventional lead-containing solder, the process of mounting electronic devices on printed wiring boards is becoming hotter (for example, the solder reflow process). Therefore, materials used in printed wiring boards and other devices are also required to be heat-resistant at temperatures above 260°C.

[0007] On the other hand, with the recent global spread of electronic devices such as smartphones and tablet terminals, reliability over a wide temperature range from low to high is required. Conventional printed wiring boards have a problem of peeling between the interlayer adhesive layer and the adjacent layer when exposed to extreme temperature changes, so the interlayer adhesive layer that constitutes a printed wiring board must have high thermal cycle resistance.

[0008] Furthermore, recent electronic devices such as smartphones and tablet terminals are required to withstand physical shocks such as being dropped.

[0009] In addition, when manufacturing a multilayer printed wiring board using a thermosetting adhesive sheet or when protecting the circuit surface of a printed wiring board using a thermosetting cover sheet with a release film, Therefore, in order to increase the density of electronic devices, a material that minimizes resin flow during the heat pressing process is required.

[0010] The present invention has been made in view of the above problems, and an object of the present invention is to provide a thermosetting resin composition that has little resin flow during a heat press process and that can form a cured product after curing that has excellent laser processability, heat resistance, thermal cycle resistance, and impact absorption properties. [Means for solving the problem]

[0011] As a result of extensive research, the present inventors have found that the problems of the present invention can be solved by the following aspects, and have thus completed the present invention. That is, the thermosetting resin composition according to the present invention is a thermosetting resin composition comprising a polyimide resin (A) which is a reaction product of a group of monomers including a dimer diamine (a-1) and a tetracarboxylic acid anhydride (a-2), at least one curing agent (B) selected from the group consisting of an epoxy compound (B-1), a maleimide compound (B-2), an isocyanate group-containing compound (B-3), a metal chelate compound (B-4), and a carbodiimide group-containing compound (B-5), and a filler (C), and the cured product obtained by heating the thermosetting resin composition at 180°C for 60 minutes satisfies the following (i) to (iii): (a) Storage modulus at 30°C is 1.0 x 10 6 ~1.0×10 11 It is Pa. (b) Storage modulus at 150°C is 1.0 × 10 4 ~1.0×10 9 It is Pa. (c) Storage modulus at 280°C is 1.0 × 10 3 ~1.0×10 9 It is Pa. [Effects of the Invention]

[0012] According to the present invention, a cured product can be formed that exhibits little resin flow during hot pressing and that, after curing, has excellent laser processability, heat resistance, thermal cycle resistance, and impact absorption properties. [Brief explanation of the drawings]

[0013] [Figure 1]1 is a schematic diagram showing a cross section of a printed wiring board near a blind via formed by laser processing; DETAILED DESCRIPTION OF THE INVENTION

[0014] An example of an embodiment to which the present invention is applied will be described below. Note that the size and ratio of each component in the following figures are for convenience of explanation and are not limited thereto. Furthermore, in this specification, the expression "any number A to any number B" means that the range includes number A as the lower limit and number B as the upper limit. Furthermore, in this specification, "sheet" includes not only "sheet" as defined by JIS, but also "film." Furthermore, the numerical values ​​specified in this specification are values ​​determined by the methods disclosed in the embodiments or examples.

[0015] <Thermosetting resin composition> The thermosetting resin composition of the present invention is a thermosetting resin composition comprising a polyimide resin (A) which is a reaction product of a monomer group including a dimer diamine (a-1) and a tetracarboxylic acid anhydride (a-2), a curing agent (B) selected from the group consisting of an epoxy compound (B-1), a maleimide compound (B-2), an isocyanate group-containing compound (B-3), a metal chelate compound (B-4), and a carbodiimide group-containing compound (B-5), and a filler (C), and the cured product obtained by heating the thermosetting resin composition at 180°C for 60 minutes satisfies the following (i) to (iii). (a) Storage modulus at 30°C is 1.0 x 10 6 ~1.0×10 11 It is Pa. (b) Storage modulus at 150°C is 1.0 × 10 4 ~1.0×10 9 It is Pa. (c) Storage modulus at 280°C is 1.0 × 10 3 ~1.0×10 9 It is Pa.

[0016] <Polyimide resin (A)> The polyimide resin (A) of the present invention is a thermosetting resin obtained by reacting a dimer diamine (a-1) with a monomer group containing a tetracarboxylic acid anhydride (a-2). The polyimide resin (A) functions as a binder resin in the thermosetting adhesive composition of the present invention. The binder resin serves as the base of the thermosetting adhesive composition and functions to hold the filler (C) described below.

[0017] <Dimer diamine (a-1)> The dimer diamine (a-1) of the present invention can be a polyamine compound in which the carboxyl group of a polybasic acid compound having a cyclic structure and 5 to 10 carbon atoms, obtained by reacting with a monobasic unsaturated fatty acid having one or more double or triple bonds and 10 to 24 carbon atoms, is converted to an amino group. For example, a compound in which the carboxyl group of a polybasic acid compound containing a dimerized fatty acid (dimer acid) is converted to an amino group by the Diels-Alder reaction using natural fatty acids such as soybean oil fatty acid, tall oil fatty acid, and rapeseed oil fatty acid, and oleic acid, linoleic acid, linolenic acid, and erucic acid, which are purified from these fatty acids. The dimer diamine (a-1) can have one or two cyclic structures. If the dimer diamine has two cyclic structures, the two rings can be independent or adjacent. The dimer diamine can also have no cyclic structure, or can be a mixture of a compound with and without a cyclic structure. The use of a diamine compound derived from a dimer acid can easily introduce a dimer skeleton into a polyimide resin.

[0018] Examples of the cyclic structure include a saturated alicyclic structure, an unsaturated alicyclic structure, and an aromatic ring. The amino group (an amino group converted from a carboxyl group) can be directly bonded to the cyclic structure, but from the viewpoint of improving solubility and flexibility, it is preferable that the amino group be bonded to the cyclic structure via an aliphatic chain. The number of carbon atoms between the amino group and the cyclic structure is preferably 2 to 25. Furthermore, from the viewpoint of improving solubility and flexibility, the dimer diamine (a-1) in the present invention preferably has a chain-like alkyl group with high flexibility and hydrophobicity as a portion other than the cyclic structure. It is preferable that one cyclic structure has two or more alkyl groups. The alkyl group preferably has 2 to 25 carbon atoms.

[0019] Dimer diamine (a-1) is preferably a dimer diamine obtained by converting the carboxyl groups of a raw material fatty acid or a composition of a trimerized or higher fatty acid into amino groups. Furthermore, dimer diamines with a reduced degree of unsaturation due to hydrogenation of the dimer diamine are particularly suitable from the viewpoints of oxidation resistance (particularly coloration at high temperatures) and suppression of gelation during synthesis.

[0020] Commercially available dimer diamines (a-1) include, for example, Priamine 1071, Priamine 1073, Priamine 1074, and Priamine 1075 (all manufactured by Croda Japan Ltd.); Versamine 551 (manufactured by BASF Japan Ltd.) and the like. The dimer diamines can be used alone or in combination of two or more.

[0021] The polyamine compound used in the polymerization of the polyimide resin (A) may be the above-mentioned dimer diamine (a-1) alone, but other polyamine compounds may also be used within the scope of the present invention. The amount of the other diamine compounds is preferably 50 mol % or less, more preferably 25 mol % or less, of the total amount of the diamine compounds used in the polyimide resin (A).

[0022] <Other diamine compounds> Other diamine compounds include, for example, 1,4-diaminobenzene, 1,3-diaminobenzene, aromatic diamines such as aminobenzene, 1,2-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, 2,6-diaminotoluene, 2,4-diaminotoluene, 3,4-diaminotoluene, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diamino-1,2-diphenylethane, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, and 3,3'-diaminodiphenyl sulfone; Examples of the diamine include aliphatic diamines such as ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,9-nonanediamine, 1,12-dodecamethylenediamine, and metaxylenediamine; and alicyclic diamines such as isophoronediamine, norbornanediamine, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 4,4'-diaminodicyclohexylmethane, and piperazine. It goes without saying that the other diamine compounds are not limited to the above structures.

[0023] Other polyamine compounds may be used in the polymerization of polyimide resin (A) within the scope of the present invention. The amount of the other diamine compounds is preferably 50 mol % or less, more preferably 25 mol % or less, of the total amount of polyamine compounds used in polyimide resin (A).

[0024] As the other polyamine compound, it is particularly preferable to use a monomer containing, as a residue, a trimer, which is a triamine obtained by converting a tricarboxylic acid derived from a monobasic unsaturated fatty acid having 10 to 24 carbon atoms. By using a polyamine compound with three or more functionalities, a branched structure can be introduced into the polyimide resin, which can increase the molecular weight and improve the heat resistance of the resulting polyimide resin.

[0025] <Tetracarboxylic acid anhydride (a-2)> The tetracarboxylic acid anhydride (a-2) of the present invention may be a known monomer. Specific examples thereof include pyromellitic dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 2,2',3,3'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenylethertetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 2,2',3,3'-benzophenonetetracarboxylic acid dianhydride, 4,4'-[propane-2 ,2-diylbis(1,4-phenyleneoxy)]diphthalic dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-cyclohexene-1,2 dicarboxylic anhydride, 1,2,3,4-benzenetetracarboxylic dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, methylene-4,4'-diphthalic dianhydride, 1,1-ethylidene-4,4'-di Phthalic dianhydride, 2,2-propylidene-4,4'-diphthalic dianhydride, 1,2-ethylene-4,4'-diphthalic dianhydride, 1,3-trimethylene-4,4'-diphthalic dianhydride, 1,4-tetramethylene-4,4'-diphthalic dianhydride, 1,5-pentamethylene-4,4'-diphthalic dianhydride, 4,4'-oxydiphthalic dianhydride, p-phenylenebis(trimellitate anhydride), thio-4,4'-diphthalic dianhydride, sulfonyl-4,4'-diphthalic dianhydride carboxylic acid dianhydride, 1,3-bis(3,4-dicarboxyphenyl)benzene dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride, 1,3-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, 1,4-bis[2-(3,4-dicarboxyphenyl)-2-propyl]benzene dianhydride, bis[3-(3,4-dicarboxyphenoxy)phenyl] phenyl]methane dianhydride, bis[4-(3,4-dicarboxyphenoxy)phenyl]methane dianhydride, 2,2-bis[3-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, bis(3,4-dicarboxyphenoxy)dimethylsilane dianhydride, 1,3-bis(3,4-dicarboxyphenyl)-1,1,3,3-tetramethyldisiloxane dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, cyclobutanetetracarboxylic dianhydride (e.g., 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, etc.), cyclohexanetetracarboxylic dianhydride (e.g., 1,2,4,5-cyclohexanetetracarboxylic dianhydride, etc.), 9 ,9-bis[4-(3,1-, 3,2-, 3,3- or 3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic dianhydride, and 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 1,2,4,5-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,4,5,8-decahydronaphthalenetetracarboxylic dianhydride, 4,8-dimethyl 1,2,5,6-hexahydronaphthalenetetracarboxylic dianhydride, 2,6-dichloro-1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,7-dichloro-1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-tetrachloro-1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,8,9,10-phenanthrenetetracarboxylic dianhydride, 2,2-bis(2,3-dicarboxyphenyl)propane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, 1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, bis(3,4-dicarboxyphenyl)sulfone dianhydride, benzene-1,2,3,4-tetracarboxylic acid dianhydride, 3,4,3',4'-benzophenonetetracarboxylic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo-3-furanyl)naphtho(1,2-C)furan-1,3-dione, etc. Among these, from the viewpoint of heat resistance and impact absorption, tetracarboxylic acid anhydrides having two or less aromatic rings per molecule are more preferred. Among these, from the viewpoint of compatibility with polyamine compounds during synthesis, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 3,3',4,4'-diphenylethertetracarboxylic acid dianhydride, 4,4'-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5(tetrahydro-2,5-dioxo) Particularly preferred is (1,2-C)-3-furanyl)naphtho(1,2-C)furan-1,3-dione. The tetracarboxylic acid anhydrides can be used alone or in combination of two or more.

[0026] The polyimide resin (A) has a reactive functional group that reacts with the curing agent (B) described later. The reactive functional group of the polyimide resin (A) is not limited, but at least one of an amino group and an anhydride group is preferred. The reactive functional group is present on the side chain or terminal of the polyimide resin. A polyimide resin having an amine or an anhydride group at the molecular terminal can be easily obtained by adjusting the ratio of the amount of diamine compound and the amount of tetracarboxylic dianhydride charged. More preferred is a polyimide resin in which an excess amount of tetracarboxylic dianhydride is blended (50 mol % or more blended) and an acid anhydride group is present at the terminal. Also, a polyimide resin in which an excess amount of diamine compound is blended (50 mol % or more blended) is blended. ) to obtain a polyimide resin having a diamine compound at its terminal, and then react it with maleic anhydride to introduce an acid anhydride group at the terminal.

[0027] <Curing agent (B)> The curing agent (B) has a functional group capable of reacting with the reactive functional group of the polyimide resin (A), and preferably has a plurality of reactive functional groups. The curing agent (B) is at least one selected from the group consisting of epoxy compounds (B-1), maleimide compounds (B-2), isocyanate group-containing compounds (B-3), metal chelate compounds (B-4), and carbodiimide group-containing compounds (B-5). By using these compounds as the curing agent (B), it is possible to prevent a decrease in storage modulus at high temperatures and suppress side etching during laser processing. The curing agents can be used alone or in combination of two or more.

[0028] <Epoxy group-containing compound (B-1)> The epoxy group-containing compound (B-1) is not particularly limited as long as it has an epoxy group in the molecule, but preferably has an average of two or more epoxy groups in one molecule. Examples of the epoxy group-containing compound include epoxy resins such as glycidyl ether epoxy resins, glycidyl amine epoxy resins, glycidyl ester epoxy resins, and cyclic aliphatic (alicyclic) epoxy resins.

[0029] Examples of glycidyl ether type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD ​​type epoxy resins, cresol novolac type epoxy resins, phenol novolac type epoxy resins, α-naphthol novolac type epoxy resins, bisphenol A type novolac type epoxy resins, dicyclopentadiene type epoxy resins, tetrabromobisphenol A type epoxy resins, brominated phenol novolac type epoxy resins, tris(glycidyloxyphenyl)methane, and tetrakis(glycidyloxyphenyl)ethane.

[0030] Examples of glycidylamine type epoxy resins include tetraglycidyldiaminodiphenylmethane, triglycidyl paraaminophenol, triglycidyl meta-aminophenol, and tetraglycidyl meta-xylylenediamine.

[0031] Examples of glycidyl ester type epoxy resins include diglycidyl phthalate, diglycidyl hexahydrophthalate, and diglycidyl tetrahydrophthalate.

[0032] Examples of cyclic aliphatic (alicyclic) epoxy resins include epoxycyclohexylmethyl-epoxycyclohexanecarboxylate and bis(epoxycyclohexyl)adipate.

[0033] As the epoxy group-containing compound, one of the above compounds can be used alone, or two or more of them can be used in combination. As the epoxy group-containing compound, from the viewpoint of high adhesiveness, it is preferable to use bisphenol A type epoxy resin, cresol novolac type epoxy resin, phenol novolac type epoxy resin, tris(glycidyloxyphenyl)methane, tetrakis(glycidyloxyphenyl)ethane, or tetraglycidylmeta-xylylenediamine, and from the viewpoint of high heat resistance, those containing tri- or more functional epoxy groups are even more preferable.

[0034] <Maleimide Group-Containing Compound (B-2)> The maleimide group-containing compound (B-2) is not particularly limited as long as it is a compound having a maleimide group in the molecule, but it is preferable to use one having an average of two or more maleimide groups in one molecule.

[0035] Specific examples of the maleimide group-containing compound of the present invention include o-phenylene bismaleimide, m-phenylene bismaleimide, p-phenylene bismaleimide, 4-methyl-1,3-phenylene bismaleimide, N,N'-(toluene-2,6-diyl)bismaleimide, 4,4'-diphenylmethane bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4,4'-diphenyl ether bismaleimide, and 4,4'-diphenylsulfonyl bismaleimide. N,N'-ethylene bismaleimide, N,N'-trimethylene bismaleimide, N,N'-propylene bismaleimide, N,N'-tetramethylene bismaleimide, N,N'-pentamethylene bismaleimide, N,N'-(1,3-pentanediyl)bis(maleimide), ... do), N,N'-hexamethylenebismaleimide, N,N'-(1,7-heptanediyl)bismaleimide, N,N'-(1,8-octanediyl)bismaleimide, N,N'-(1,9-notanediyl)bismaleimide, N,N'-(1,10-decanediyl)bismaleimide, N,N'-(1,11-undecanediyl)bismaleimide, N,N'-(1,12-dodecanediyl)bismaleimide, N,N'-[(1,4-phenylene)bismethylene]bismaleimide, N,N'-[(1,2-phenylene)bismethylene]bismaleimide, N, N'-[(1,3-phenylene)bismethylene]bismaleimide, 1,6'-bismaleimide-(2,2,4-trimethyl)hexane, N,N'-[(methylimino)bis(4,1-phenylene)]bismaleimide, N,N'-(2-hydroxypropane-1,3-diylbisiminobiscarbonylbisethylene)bismaleimide, N,N'-(dithiobisethylene)bismaleimide, N,N'-[hexamethylenebis(iminocarbonylmethylene)]bismaleimide, N,N'-carbonylbis(1,4-phenylene)bismaleimide, N,N',N''-[Nitrilotris(ethylene)]trismaleimide, N,N',N''-[Nitrilotris(4,1-phenylene)]trismaleimide, N,N'-[p-phenylenebis(oxy-p-phenylene)]bismaleimide, N,N'-[methylenebis(oxy)bis(2-methyl-1,4-phenylene)]bismaleimide, N,N'-[methylenebis(oxy-p-phenylene)]bis(maleimide)N,N'-[dimethylsilylenebis[(4,1-phenylene)(1,3,4,-oxadiazole-5,2-diyl)(4,1- phenylene)]]bismaleimide, N,N'-[(1,3-phenylene)bisoxybis(3,1-phenylene)]bismaleimide, 1,1'-[3'-oxospiro[9H-xanthene-9,1'(3'H)-isobenzofuran]-3,6-diyl]bis(1H-pyrrole-2,5-dione), N,N'-(3,3'-dichlorobiphenyl-4,4'-diyl)bismaleimide, N,N'-(3,3'-dimethylbiphenyl-4,4'-diyl)bismaleimide, N,N'-(3,3'-dimethoxybiphenyl-4,4'-diyl)bismaleimide Imide, N,N'-[methylenebis(2-ethyl-4,1-phenylene)]bismaleimide, N,N'-[methylenebis(2,6-diethyl-4,1-phenylene)]bismaleimide, N,N'-[methylenebis(2-bromo-6-ethyl-4,1-phenylene)]bismaleimide, N,N'-[methylenebis(2-methyl-4,1-phenylene)]bismaleimide, N,N'-[ethylenebis(oxyethylene)]bismaleimide, N,N'-[sulfonylbis(4,1-phenylene)bis(oxy)bis(4,1-phenylene)]bismaleimide N,N'-[naphthalene-2,7-diylbis(oxy)bis(4,1-phenylene)]bismaleimide, N,N'-[p-phenylenebis(oxy-p-phenylene)]bismaleimide, N,N'-[(1,3-phenylene)bisoxybis(3,1-phenylene)]bismaleimide, N,N'-(3,6,9-trioxaundecane-1,11-diyl)bismaleimide, N,N'-[isopropylidenebis[p-phenyleneoxycarbonyl(m-phenylene)]]bismaleimide, N,N'-[isopropylidenebis[p, -phenyleneoxycarbonyl(p-phenylene)]]bismaleimide, N,N'-[isopropylidenebis[(2,6-dichlorobenzene-4,1-diyl)oxycarbonyl(p-phenylene)]]bismaleimide, N,N'-[(phenylimino)bis(4,1-phenylene)]bismaleimide, N,N'-[azobis(4,1-phenylene)]bismaleimide, N,N'-[1,3,4-oxadiazole-2,5-diylbis(4,1-phenylene)]bismaleimide, 2,6-bis[4-(maleimido-N-yl)phenoxy]benzyl N,N'-[1,3,4-oxadiazole-2,5-diylbis(3,1-phenylene)]bismaleimide, N,N'-[bis[9-oxo-9H-9-phospha(V)-10-oxaphenanthrene-9-yl]methylenebis(p-phenylene)]bismaleimide, N,N'-[hexafluoroisopropylidenebis[p-phenyleneoxycarbonyl(m-phenylene)]]bismaleimide, N,N'-[carbonylbis[(4,1-phenylene)thio(4,1-phenylene)]]bismaleimide, N,N'-carbonylbis( p-phenyleneoxy-p-phenylene)bismaleimide, N,N'-[5-tert-butyl-1,3-phenylenebis[(1,3,4-oxadiazole-5,2-diyl)(4,1-phenylene)]]bismaleimide, N,N'-[cyclohexylidenebis(4,1-phenylene)]bismaleimide, N,N'-[methylenebis(oxy)bis(2-methyl-1,4-phenylene)]bismaleimide, N,N'-[5-[2-[5-(dimethylamino)-1-naphthylsulfonylamino]ethylcarbamoyl]-1,3-phenylene]bismaleimide Examples of suitable polyfunctional maleimides include imide, N,N'-(oxybisethylene)bismaleimide, N,N'-[dithiobis(m-phenylene)]bismaleimide, N,N'-(3,6,9-trioxaundecane-1,11-diyl)bismaleimide, N,N'-(ethylenebis-p-phenylene)bismaleimide, BMI-689, BMI-1500, BMI-1700, BMI-3000, BMI-5000, and BMI-9000 manufactured by Designer Molecules, and ODA-BMI and BAF-BMI manufactured by JFE Chemical Corporation.

[0036] Further, polyfunctional maleimides obtained by reacting polyfunctional amines with maleic anhydride can be used. Examples of polyfunctional amines include isophoronediamine, dicyclohexylmethane-4,4'-diamine, and Huntsman Corporation's Jeffamine D-230, HK-511, D-400, XTJ-582, D-2000, XTJ-578, XTJ-509, XTJ-510, T-403, and T-5000, which have terminally aminated polypropylene glycol backbones; XTJ-500, XTJ-501, XTJ-502, XTJ-504, XTJ-511, XTJ-512, and XTJ-590, which have terminally aminated ethylene glycol backbones; and XTJ-542, XTJ-533, XTJ-536, XTJ-548, and XTJ-559, which have terminally aminated polytetramethylene glycol backbones.

[0037] <Isocyanate group-containing compound (B-3)> The isocyanate group-containing compound (B-3) is not particularly limited as long as it is a compound having an isocyanate group in the molecule. Specific examples of the isocyanate group-containing compound having one isocyanate group per molecule include n-butyl isocyanate, isopropyl isocyanate, phenyl isocyanate, benzyl isocyanate, (meth)acryloyloxyethyl isocyanate, 1,1-bis[(meth)acryloyloxymethyl]ethyl isocyanate, vinyl isocyanate, allyl isocyanate, (meth)acryloyl isocyanate, and isopropenyl-α,α-dimethylbenzyl isocyanate. Also, 1,6-diisocyanatohexane, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, xylylene diisocyanate, 2,4-tolylene diisocyanate, toluene diisocyanate, 2,4-toluene diisocyanate, hexamethylene diisocyanate, 4-methyl-m-phenylene diisocyanate, naphthylene diisocyanate, paraphenylene diisocyanate Compounds obtained by reacting equimolar amounts of a diisocyanate compound, such as tetramethylxylylene diisocyanate, cyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, cyclohexyl diisocyanate, tolidine diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, m-tetramethylxylylene diisocyanate, p-tetramethylxylylene diisocyanate, or dimer acid diisocyanate, with a vinyl monomer containing a hydroxyl group, a carboxyl group, or an amide group can also be used as the isocyanate compound.

[0038] Specific examples of the isocyanate group-containing compound having two isocyanate groups in one molecule include aromatic diisocyanates such as 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and 4,4',4"-triphenylmethane triisocyanate; Aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate; aromatic aliphatic diisocyanates such as ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate; Examples of the diisocyanate include alicyclic diisocyanates such as 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate (also known as isophorone diisocyanate), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,3-bis(isocyanatemethyl)cyclohexane, and 1,4-bis(isocyanatemethyl)cyclohexane.

[0039] Specific examples of the isocyanate group-containing compound having three isocyanate groups in one molecule include aromatic polyisocyanates, aliphatic polyisocyanates such as lysine triisocyanate, aromatic aliphatic polyisocyanates, and alicyclic polyisocyanates, as well as the trimethylolpropane adducts of the diisocyanates described above, biuret products obtained by reaction with water, and trimers having an isocyanurate ring.

[0040] As the isocyanate group-containing compound, blocked isocyanate group-containing compounds in which the isocyanate groups in the various isocyanate group-containing compounds exemplified above are protected with ε-caprolactam, MEK oxime, or the like can also be used. Specific examples include compounds in which the isocyanate group of the isocyanate group-containing compound is blocked with ε-caprolactam, methyl ethyl ketone (hereinafter referred to as MEK) oxime, cyclohexanone oxime, pyrazole, phenol, etc. In particular, hexamethylene diisocyanate trimer having an isocyanurate ring and blocked with MEK oxime or pyrazole is highly preferred when used in the present invention because it has excellent adhesive strength to polyimide and copper and excellent heat resistance. Furthermore, from the viewpoint of heat resistance, it is preferable that the compound has tri- or more functional isocyanate groups.

[0041] <Metal chelate compounds (B-4)> The metal chelate compound (B-4) is an organometallic compound composed of a metal and an organic substance, which reacts with the reactive functional groups of the binder resin to form crosslinks. The type of organometallic compound is not particularly limited, but examples include organoaluminum compounds, organotitanium compounds, and organozirconium compounds. The bond between the metal and the organic substance may be a metal-oxygen bond, but is not limited to a metal-carbon bond. Furthermore, the bond between the metal and the organic substance may be a chemical bond, a coordinate bond, or an ionic bond. Furthermore, a trifunctional or higher functional group is preferable from the viewpoint of heat resistance.

[0042] The organoaluminum compound is preferably an aluminum metal chelate compound. Examples of the aluminum metal chelate compound include ethyl acetoacetate aluminum diisopropylate, aluminum tris(ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bis(ethyl acetoacetate), aluminum tris(acetylacetate), aluminum monoacetylacetate bis(ethyl acetoacetate), aluminum di-n-butoxide monomethyl acetoacetate, aluminum diisobutoxide monomethyl acetoacetate, aluminum di-sec-butoxide monomethyl acetoacetate, aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum sec-butylate, and aluminum ethylate.

[0043] The organic titanium compound is preferably a titanium metal chelate compound. Examples of titanium metal chelate compounds include titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, titanium octylene glycolate, titanium ethylacetoacetate, titanium-1,3-propanedioxybis(ethylacetoacetate), polytitanium acetylacetonate, tetraisopropyl titanate, tetra-normal butyl titanate, butyl titanate dimer, tetraoctyl titanate, diamyl titanate, tetratertiary butyl titanate, tetrastearyl titanate, titanium isostearate, tri-n-butoxytitanium monostearate, di-i-propoxytitanium distearate, titanium stearate, di-i-propoxytitanium diisostearate, (2-n-butoxycarbonylbenzoyloxy)tributoxytitanium, etc. The organic zirconium compound is preferably a zirconium metal chelate compound. Examples of the zirconium metal chelate compound include zirconium tetraacetylacetonate, zirconium tributoxyacetylacetonate, zirconium monobutoxyacetylacetonate bis(ethylacetoacetate), zirconium dibutoxybis(ethylacetoacetate), zirconium tetraacetylacetonate, normal propyl zirconate, normal butyl zirconate, zirconium stearate, and zirconium octylate. Among these, organic titanium compounds and organic zirconium compounds are preferred in terms of thermosetting reactivity.

[0044] <Carbodiimide Group-Containing Compound (B-5)> The carbodiimide group-containing compound (B-5) is not particularly limited as long as it has a carbodiimide group in the molecule. Examples of the carbodiimide group-containing compound include Carbodilite V-01, V-03, V-05, V-07, and V-09 (Nisshinbo Chemical Inc.), and cyclic carbodiimide (Teijin Limited). From the viewpoint of heat resistance, compounds having an average of three or more carbodiimide groups per molecule are preferred.

[0045] The curing agent (B) used in the present invention preferably contains an aromatic ring structure. By containing a bulky aromatic ring, molecular motion of the thermosetting resin composition of the present invention can be suppressed. This has the effect of alleviating stress that occurs during thermal cycling.

[0046] The curing agent (B) used in the present invention preferably contains epoxy groups, maleimide groups, isocyanate groups, metal chelate compounds, and carbodiimide group-containing compounds in a total amount of 1 to 20 parts by mass, more preferably 1 to 15 parts, and even more preferably 3 to 10 parts, relative to the polyimide resin (A). By adding 1 to 20 parts of curing agent (B), it is possible to suppress the storage modulus of the cured product and to suppress the occurrence of cracks due to stress caused by sudden temperature changes during thermal cycling.

[0047] <Filler (C)> Next, the filler (C) used in the present invention will be described in detail. The thermosetting resin composition of the present invention contains a filler for the purpose of controlling the elastic modulus of the cured product.

[0048] The filler (C) is not particularly limited, and examples of its shape include spherical, powdery, fibrous, needle-like, and scale-like shapes. Examples of the filler (C) include fluorine fillers such as polytetrafluoroethylene powder and modified products thereof, tetrafluoroethylene-perfluoroalkyl vinyl ether powder, tetrafluoroethylene-ethylene powder, tetrafluoroethylene-hexafluoropropylene powder, tetrafluoroethylene-vinylidene fluoride powder, tetrafluoroethylene-hexafluoropropylene-perfluoroalkyl vinyl ether powder, polychlorotrifluoroethylene powder, chlorotrifluoroethylene-ethylene powder, chlorotrifluoroethylene-vinylidene fluoride powder, polyvinylidene fluoride powder, and polyvinyl fluoride powder. Other fillers include polyethylene powder, polyacrylate powder, epoxy resin powder, polyamide powder, polyimide powder, polyurethane powder, liquid crystal polymer beads, polysiloxane powder, etc., as well as polymer fillers such as multilayer core-shell fillers using silicone, acrylic, styrene butadiene rubber, butadiene rubber, etc.; (poly)phosphate compounds such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium amide phosphate, ammonium amide polyphosphate, carbamate phosphate, and carbamate polyphosphate; organic phosphate ester compounds, phosphazene compounds, phosphonic acid compounds, phosphinic acid compounds such as aluminum diethylphosphinate, aluminum methylethylphosphinate, aluminum diphenylphosphinate, aluminum ethylbutylphosphinate, aluminum methylbutylphosphinate, and aluminum polyethylenephosphinate; phosphine oxide compounds, phosphorus-based fillers such as phosphorus compounds, phosphorus compounds, phosphorus compounds; Nitrogen-based fillers such as benzoguanamine, melamine, melam, melem, melon, melamine cyanurate, cyanuric acid compounds, isocyanuric acid compounds, triazole compounds, tetrazole compounds, diazo compounds, and urea; Examples of inorganic fillers include silica, hollow silica, porous silica, mica, talc, kaolin, clay, hydrotalcite, wollastonite, xonotlite, silicon nitride, boron nitride, aluminum nitride, calcium hydrogen phosphate, calcium phosphate, glass flakes, hydrated glass, calcium titanate, sepiolite, magnesium sulfate, aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, calcium hydroxide, titanium oxide, tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, antimony oxide, nickel oxide, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc borate, and aluminum borate.

[0049] From the viewpoint of impact absorption, it is preferable to use a fluorine filler, boron nitride, a liquid crystal polymer, and silica. In the present invention, these fillers (C) can be used alone or in combination.

[0050] Average particle size D of filler (C) 50 The average particle diameter D of the filler (C) is preferably 0.1 to 25 μm. 50 When the average particle diameter D of the filler (C) is 0.1 to 25 μm, the mechanical properties of the cured product can be improved, and the impact absorption can be improved. 50 It is more preferable that the thickness is in the range of 2 to 10 μm.

[0051] The content of filler (C) is preferably 5 to 60 parts by mass per 100 parts by mass of the binder resin component. By setting the filler content to 60 parts by mass or less, the storage modulus of the cured film can be controlled to a certain level or less, thereby suppressing the occurrence of cracks, peeling, and other problems caused by stress due to sudden temperature changes during thermal cycling. Furthermore, by setting the filler content to 5 parts by mass or more, the storage modulus can be maintained high near room temperature, reducing swelling during the desmearing process after laser processing and reducing the occurrence of peeling or lifting at the interface between the copper-clad laminate and the thermosetting resin composition of the present invention. The filler content is more preferably 5 to 40 parts by mass, even more preferably 5 to 30 parts by mass, and most preferably 5 to 20 parts by mass or less.

[0052] When the thermosetting resin composition of the present invention is used to form a thermosetting adhesive sheet as described below, the filler (C) has an average particle size D 50 and the film thickness of the thermosetting adhesive sheet, the value calculated by (Equation 1) is preferably 0.8 or less, more preferably 0.1 or less, and even more preferably 0.05 or less. By setting it to 0.8 or less, the binder resin component can sufficiently cover the filler surface, allowing for good adhesion to the adherend and making peeling or lifting less likely to occur during thermal cycling. (Formula 1) Average particle size D of filler (C) 50 (μm) / Thermosetting adhesive sheet film thickness (μm)

[0053] The method for adding the filler (C) is not particularly limited, and any conventionally known method may be used, but specific examples include a method of adding the filler to a polymerization reaction liquid before or during polymerization of the binder resin, a method of kneading the filler into the binder resin using a three-roll mill, a method of preparing a dispersion containing the filler and mixing this with the binder resin, etc. Furthermore, in order to disperse the filler well and stabilize the dispersion state, a dispersant, a thickener, etc. may also be used within a range that does not affect the physical properties of the thermosetting resin composition.

[0054] <Other additives> In addition, the thermosetting resin composition of the present invention may further contain, as optional components, energy ray absorbers, dyes, pigments, antioxidants, polymerization inhibitors, antifoaming agents, leveling agents, ion scavengers, moisturizing agents, viscosity modifiers, preservatives, antibacterial agents, antistatic agents, antiblocking agents, infrared absorbers, electromagnetic wave shielding agents, and the like, within the scope of not impairing the object of the invention. From the viewpoint of improving laser processability, it is preferable to incorporate an energy ray absorber.

[0055] <Storage Modulus of Thermosetting Resin Composition> The storage modulus can be measured using a DVA (dynamic viscoelastic analysis) measuring device or the like. The storage modulus at each temperature can be determined from the viscoelastic curve of the cured product obtained using this device.

[0056] The cured product obtained by heating the thermosetting resin composition of the present invention at 180° C. for 60 minutes satisfies (i) to (iii). (a) Storage modulus at 30°C is 1.0 x 10 6 ~1.0×10 11 It is Pa. (b) Storage modulus at 150°C is 1.0 × 10 4 ~1.0×10 9 It is Pa. (c) Storage modulus at 280°C is 1.0 × 10 3 ~1.0×10 9 It is Pa.

[0057] [Storage modulus at 30℃] The cured product obtained by heating the thermosetting resin composition of the present invention at 180°C for 60 minutes has a storage modulus of 1.0 × 10 at 30°C. 6 ~1.0×10 11 Pa, 1.0 x 10 7 ~1.0×10 10 Pa is preferable, and 1.0×10 8 ~1.0×10 9 Pa is more preferred.

[0058] The storage modulus at 30°C is 1.0 x 10 11 By setting the stress to 1.0×10 Pa or less, it is possible to suppress the occurrence of cracks due to the stress caused by the sudden temperature change during the thermal cycle. 6 By setting the elastic modulus at 30°C or more, penetration of the desmear solution in the desmearing step can be suppressed, peeling or lifting at the interface between the copper-clad laminate and the thermosetting resin composition of the present invention can be suppressed, and resistance to the desmear solution can be improved. The storage modulus at 30°C can be controlled by adjusting the type and amount of filler (C) added.

[0059] [Storage modulus at 150℃] The thermosetting resin composition of the present invention was then heated at 180°C for 60 minutes to obtain a cured product having a storage modulus of 1.0 x 10 at 150°C. 4 ~1.0×10 9 Pa, 1.0 x 10 5 ~1.0×10 8 Pa is preferable, and 1.0×10 6 ~1.0×10 7 Pa is more preferred.

[0060] The storage modulus at 150°C is 1.0 x 10 9 By setting the temperature to 1.0×10 Pa or less, the occurrence of cracks due to the stress caused by the sudden temperature change during the thermal cycle can be suppressed, as in the case of 30°C. 4 By adjusting the storage modulus at 150°C to 100 Pa or more, the cohesive strength of the cured film of the thermosetting resin composition can be increased, and when the composition is used as an interlayer adhesive thermosetting resin for a multilayer printed wiring board, resin flow can be suppressed and dimensional stability can be ensured. The storage modulus at 150°C can also be controlled by adjusting the type and amount of filler (C) added.

[0061] The thermal cycle resistance is measured by repeating thermal cycles in the range of about -30°C to about 150°C, so the storage modulus at both room temperature and high temperatures is relevant. Therefore, the thermal cycle resistance is measured when the storage modulus at 30°C is 1.0 x 10 11Pa or less, and the storage modulus at 150°C is 1.0 x 10 9 By keeping the storage modulus at 30°C below 1.0 x 10 Pa, it is possible to suppress the occurrence of cracks due to stress caused by sudden temperature changes during thermal cycles. 9 Pa or less, and the storage modulus at 150°C is 1.0 x 10 7 When the tensile strength is 100 Pa or less, particularly excellent thermal cycle resistance can be exhibited.

[0062] [Storage modulus at 280℃] The cured product obtained by heating the thermosetting resin composition of the present invention at 180°C for 60 minutes has a storage modulus of 1.0 × 10 at 280°C. 3 ~1.0×10 9 Pa, 1.0 x 10 4 ~1.0×10 8 Pa is preferable, and 1.0×10 5 ~1.0×10 7 Pa is more preferred.

[0063] The storage modulus at 280°C is 1.0 x 10 9 By setting the tensile strength to 1.0×10 Pa or less, stress when high temperature heat is applied in the solder mounting process can be alleviated, crack occurrence can be suppressed, and heat resistance can be improved. 3 By setting the storage modulus at 280°C or higher, even when high heat is applied by a laser in the laser processing step for forming blind vias or through-hole vias, side etching can be suppressed without thermal sagging, improving laser processability. The storage modulus at 280°C can be adjusted by the type of curing agent (B).

[0064] <Loss tangent (tanδ) peak> The following explains how to determine the peak value of the loss tangent (tan δ). The storage modulus can be measured using a DVA (dynamic viscoelastic analysis) measuring device or the like. From the viscoelastic curve of the cured product obtained using this device, the loss tangent (tan δ) is calculated at each temperature from the storage modulus and loss modulus at each temperature, and plotted based on (Equation 2). The point at which the tan δ curve reaches its maximum is taken as the peak value. If there are multiple maximum points, the value closest to room temperature (23°C) is taken as the tan δ peak of the cured product. (Formula 2) (loss tangent; tanδ) = (loss modulus) / (storage modulus)

[0065] The cured product obtained by heating the thermosetting resin composition of the present invention at 180°C for 60 minutes preferably has a loss tangent (tanδ) peak value at 0 to 280°C of 0.3 or more, more preferably 0.5 or more, and even more preferably 0.7 or more. A loss tangent (tanδ) peak value of 0.3 or more increases impact diffusivity, allowing external impact to be dissipated. The loss tangent (tanδ) can be increased by having two or less aromatic rings in one structural unit derived from the tetracarboxylic anhydride (a-2) in the polyimide resin (A), thereby increasing the degree of freedom of molecular motion of the polyimide resin (A), and allowing flexible molecular motion in response to external impact, thereby improving impact diffusivity.

[0066] The thermosetting adhesive composition of the present invention can be applied to embodiments such as a thermosetting adhesive sheet, a thermosetting cover sheet with a release film, and a copper-clad laminate, which will be described later. When these embodiments are processed and incorporated into a printed wiring board, the thermosetting adhesive composition functions as a thermosetting composition for bonding layers of the printed wiring board.

[0067] <Thermosetting adhesive sheet> The thermosetting adhesive sheet is a sheet formed from the thermosetting resin composition of the present invention. The thermosetting adhesive sheet is used as an adhesive member for printed wiring boards and electronic devices, and has the function of adhering and holding other members. The thermosetting adhesive sheet is sandwiched between the members to be bonded to form a temporary bond, and then hardened by heating or a heat press process, thereby adhering the adherends together.

[0068] <Method for manufacturing thermosetting adhesive sheet> A thermosetting adhesive sheet can be produced, for example, by applying a coating solution containing a polyimide resin (A), a curing agent (B), a filler (C), and other optional components and a solvent to one side of a release film, removing the organic solvent or other liquid medium contained therein, drying the resulting thermosetting adhesive sheet, and laminating another release film on the surface of the resulting thermosetting adhesive sheet to obtain a thermosetting adhesive sheet with double-sided release films. Laminating both sides with release films prevents surface contamination of the thermosetting adhesive sheet. The thermosetting adhesive sheet can be isolated by peeling off the release films. The two release films can be of the same or different types. By using release films with different release properties, it is possible to vary the strength of the release force, making it easier to peel them off in order.

[0069] The coating method can be selected from known methods such as comma coating, knife coating, die coating, lip coating, roll coating, curtain coating, bar coating, gravure printing, flexographic printing, screen printing, dip coating, spray coating, and spin coating.

[0070] The thickness of the thermosetting adhesive sheet after drying is preferably 5 μm to 500 μm, more preferably 10 μm to 100 μm, in order to ensure sufficient adhesiveness and ease of handling.

[0071] <Thermosetting cover sheet with release film> A thermosetting cover sheet with a release film has a thermosetting adhesive sheet sandwiched between a release film and a cover resin layer. In other words, a thermosetting cover sheet is a thermosetting adhesive sheet with a double-sided release film, with the release film on one side replaced with a cover resin layer, and the manufacturing method is also the same.

[0072] The cover resin layer is an insulating film, and the insulating film may be made of one or more resins selected from the group consisting of, for example, polyimide, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polybutylene terephthalate, polyether ether ketone, and fluorine-based resins.

[0073] The fluorine-based resin for the insulating film is not particularly limited, and examples thereof include one or more selected from the group consisting of polytetrafluoroethylene, polytetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, difluoroethylene-trifluoroethylene copolymer, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, and polyvinylidene fluoride.

[0074] <Use of thermosetting adhesive sheets, thermosetting adhesive sheets with release films, and thermosetting cover sheets with release films> A copper-clad laminate or a printed wiring board can be obtained by using the thermosetting adhesive sheet with a release film of the present invention. A copper-clad laminate is a laminate in which a copper foil and an insulating film are laminated together via an adhesive layer which is a cured product of a thermosetting adhesive sheet obtained from the thermosetting resin composition of the present invention. Such a copper-clad laminate can be obtained, for example, by sequentially peeling off the release film from the thermosetting adhesive sheet with release film of the present invention, superimposing a copper foil and an insulating film on each side of the thermosetting adhesive sheet (this process is sometimes called temporary bonding), and then thermally curing the thermosetting adhesive sheet between the copper foil and the insulating film through a heating or heat pressing process. Alternatively, a copper-clad laminate can be obtained by applying a coating solution for forming a thermosetting adhesive sheet onto an insulating film, drying it, placing copper foil on the formed thermosetting adhesive sheet, and then subjecting the sheet to a heating or heat pressing process to thermal curing of the thermosetting adhesive sheet between the copper foil and the insulating film. Copper-clad laminates may have copper foil on both outermost layers, such as copper foil / adhesive layer / insulating film / adhesive layer / copper foil, or an inner copper foil layer may be provided. When multiple thermosetting adhesive sheets are used to laminate copper foil or insulating film, multiple temporary bonding steps may be performed, followed by heat curing of multiple thermosetting adhesive sheets at the same time.

[0075] <Printed wiring board> The copper foil in a copper-clad laminate can be processed by etching or other methods to form signal and ground circuits, resulting in a printed wiring board. The release film is peeled off from the thermosetting cover sheet with a release film, and the thermosetting adhesive sheet surface is attached to the circuit surface. This heat-curing process forms a coverlay consisting of a cured cover resin layer / adhesive sheet. This coverlay can be used to protect the signal circuit or as a substrate for further multilayering. As a method for providing a signal circuit or a ground circuit, for example, a photosensitive etching resist layer is formed on the copper foil of a copper-clad laminate, exposed to light through a mask film having a circuit pattern, and only the exposed areas are hardened. Next, the copper foil in the unexposed areas is removed by etching, and the remaining resist layer is peeled off, thereby forming a conductive circuit from the copper foil. .

[0076] The printed wiring board of the present invention can also be obtained without using a copper-clad laminate. For example, a conductor pattern can be formed by printing on a flexible, insulating plastic film such as polyester, polyimide, liquid crystal polymer, or PTFE film, and then a protective layer can be placed over the conductor pattern via the thermosetting adhesive sheet of the present invention, followed by heating and pressing to harden the thermosetting adhesive sheet, thereby obtaining a flexible printed wiring board provided with a protective layer. Alternatively, only the necessary circuits can be formed on a flexible, insulating plastic film by means of sputtering, plating, or the like, and then a flexible printed wiring board can be obtained in which a protective layer is formed via the cured product of the thermosetting adhesive sheet of the present invention.

[0077] Furthermore, a thermosetting adhesive sheet obtained by peeling off the release film from the thermosetting adhesive sheet with release film of the present invention can be sandwiched between multiple flexible printed wirings, and the thermosetting adhesive sheet can be cured by applying heat and pressure, thereby obtaining a multilayer flexible printed wiring board.

[0078] In the printed wiring board of the present invention, via openings such as blind vias and through holes may be provided to provide electrical continuity between a cured product layer obtained by curing a thermosetting resin composition or between multiple copper foils arranged on either side of a protective layer. Via openings are generally formed by laser processing using a laser beam or drilling using a drill, but laser processing is preferred from the viewpoint of improving the shape accuracy of the via openings.

[0079] The storage modulus of the cured layer obtained by curing the thermosetting resin composition at 280°C was 1.0 × 10 3 ~1.0×10 9 By setting the storage modulus at Pa, it is possible to maintain the storage modulus even when heat is applied by laser processing, and side etching can be suppressed.

[0080] Generally, after forming a via opening by laser processing or drilling, there is a desmear process to remove the remaining resin (smear). This desmear process can be a dry process using plasma or a wet process using an etching solution such as potassium permanganate. Although the dry process is suitable for desmearing small diameter vias, there are many issues such as the need for special gases and the time it takes to create a vacuum, so even now the wet process is widely used for desmearing.

[0081] The storage modulus at 30°C is 1.0 x 10 6 ~1.0×10 11 By setting the thickness to Pa, it is possible to suppress the penetration of the desmear solution in the desmearing step, and to suppress the occurrence of peeling or lifting at the interface between the copper-clad laminate and the thermosetting resin composition of the present invention.

[0082] Using the printed wiring board of the present invention, various electronic devices such as smartphones, tablet terminals, cameras, etc. can be manufactured. [Example]

[0083] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the examples, "parts" means "parts by mass" and "%" means "% by mass". In Example 10, 、18~20 Reference Example 10 is intended to conform to the scope of the claims. 、18~20 shall be read as follows.

[0084] The acid value of the resin was measured by the following method. <Acid value measurement> The acid value was measured in accordance with JIS K0070. Approximately 1 g of sample was precisely weighed and placed in a stoppered Erlenmeyer flask, and the mixture was diluted with tetrahydrofuran and ethanol (volume ratio: tetrahydrofuran / ethanol). Add 100 ml of the (2 / 1) mixture and dissolve. Add phenolphthalein test solution as an indicator, and titrate with 0.1 N alcoholic potassium hydroxide solution. The endpoint is when the indicator retains a pale pink color for 30 seconds. The acid value is calculated using the following formula (unit: mgKOH / g). Formula (3) Acid value (mgKOH / g)=(5.611×a×F) / S S: Amount of sample collected (g) a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml) F: Potency of 0.1N alcoholic potassium hydroxide solution

[0085] [Synthesis Example 1] <Synthesis of polyimide resin (P1)> Into a four-neck flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, inlet tube, and thermometer, 378.7 g of a dimer diamine (Priamine 1075) having 36 carbon atoms as a polyamine compound and 378.7 g of bisphenol A dianhydride (4,4'-[propane-2,2-diylbis(1,4-phenyleneoxy)]diphthalic dianhydride) (BISDA-1 380.0 g of 100.000) and 1100 g of cyclohexanone as a solvent were charged and stirred until homogeneous. After homogeneity was achieved, the temperature was raised to 110°C, and after 30 minutes, the temperature was raised to 140°C. Once the temperature reached 140°C, the reaction was continued at that temperature for 10 hours to allow the dehydration reaction to continue, yielding polyimide resin (A1) with a weight-average molecular weight of 54,000, an acid value of 6.4 mg KOH / g, and an amine value of 0.3 mg KOH / g.

[0086] [Synthesis Examples 2 to 6] As shown in Table 1, polyimide resins (A2) to (A6) were obtained in the same manner as in Synthesis Example 1, except that the types and amounts of dimer diamine (a-1) and tetracarboxylic acid anhydrides (a-2) were changed.

[0087] [Table 1]

[0088] [Example 1] <<Production of thermosetting resin composition (coating liquid)>> A container was charged with 100 parts of polyimide resin (A1), 5 parts of an epoxy group-containing compound (B-1-1) described below, and 20 parts of boron nitride in terms of solid content, and a mixed solvent (toluene:MEK=9:1 (weight ratio)) was added so that the nonvolatile content concentration was 40%, and the mixture was stirred with a disper for 10 minutes to obtain a thermosetting resin composition (coating liquid). According to the methods described below, the storage modulus and loss modulus of the cured product were determined, and the resin flow as a thermosetting adhesive sheet, laser processability before and after immersion in a desmear solution, heat resistance, thermal cycle resistance, and impact absorption were evaluated. The results are shown in Tables 2 to 4.

[0089] [Examples 2 to 22, Comparative Examples 1 to 5] As shown in Tables 2 to 4, thermosetting resin compositions (coating solutions) were obtained in the same manner as in Example 1, except that the types and amounts of binder resins, curing agents, and fillers were changed, and the compositions were evaluated in the same manner.

[0090] {Raw material: binder resin} Polyimide resin (A): (A1) to (A6) described in Synthesis Examples 1 to 6 (A7): Vylon 637, a polyester resin with an acid value of 5 mg KOH / g, a weight-average molecular weight of 30,000, and a Tg of 21°C (manufactured by Toyobo Co., Ltd.)

[0091] {Raw material: Hardener (B)} Epoxy group-containing compound (B-1-1): "ELM-434" (glycidylamine type epoxy resin, epoxy equivalent 100g / eq, tetrafunctional) manufactured by Sumitomo Chemical Co., Ltd. Epoxy group-containing compound (B-1-2): "YX-8800" (glycidyl ether type epoxy resin, epoxy equivalent 180g / eq, bifunctional) manufactured by Mitsubishi Chemical Corporation Maleimide group-containing compound (B-2): "MIR-3000" (biphenylaralkyl type Maleimide resin, multifunctional) manufactured by Nippon Kayaku Co., Ltd. Isocyanate group-containing compound (B-3): "TKA-100" (isocyanurate type isocyanate) Isocyanate compound, isocyanate equivalent: 180g / eq, trifunctional) manufactured by Asahi Kasei Corporation Metal chelate compound (B-4): "Orgatix ZC-150" (organic zirconia compound, tetrafunctional) manufactured by Matsumoto Fine Chemical Co., Ltd. Carbodiimide group-containing compound (B-5): "Carbodilite V-05" (carbodiimide equivalent: 262 g / eq, multifunctional) manufactured by Nisshinbo Chemical Co., Ltd. Polyamino group-containing compound: "BAPP" (bifunctional) manufactured by Seika Corporation

[0092] {Raw material: Filler (C)} Boron nitride: "SP-2" (average particle size D 50 ;4.0μm) Denka Silica: "SC2050-MB" (average particle size D 50 ;0.5μm) Alumina manufactured by Admatechs: "HT Grade" (average particle diameter D 50 = 1.2 μm, average circularity = 0.90) Tokuyama Co., Ltd. PTFE: "KT-300" (average particle size D 50 ;10.0μm) Kitamura Co., Ltd. Liquid crystal polymer: "E101-S" (average particle size D 50 17.5 μm) manufactured by Sumitomo Chemical Co., Ltd.

[0093] <<Measurement of storage modulus and loss tangent of cured product>> <Preparation of cured product for measurement> The coating solution obtained in each example and comparative example was evenly coated using a doctor blade onto a 50 μm thick heavy release film (a polyethylene terephthalate (PET) film coated with a heavy release agent) so that the thickness after drying would be 200 μm. The film was then dried at 100°C for 2 minutes and cooled to room temperature to form a thermosetting adhesive sheet with a single-sided release film. Next, the thermosetting adhesive sheet surface of the obtained thermosetting adhesive sheet with one-sided release film was superimposed on a 50 μm thick light release film (a polyethylene terephthalate (PET) film coated with a light release agent), to obtain a thermosetting adhesive sheet with double-sided release films consisting of a heavy release film / thermosetting adhesive sheet / light release film. The obtained thermosetting adhesive sheet was thermally cured at 180°C for 1 hour under 2 MPa, and the heavy release film and light release film were peeled off to obtain a 200 µm thick cured product of the thermosetting resin composition.

[0094] <Method for measuring storage modulus and loss tangent> Measurement specimens measuring 5 mm x 30 mm were cut from the obtained cured product and cooled to 0°C. Then, the specimens were heated to 300°C at a rate of 10°C / min using a dynamic viscoelasticity measuring device "DVA200" (manufactured by IT Measurement Control Co., Ltd.), and the viscoelasticity was measured at an oscillation frequency of 10 Hz. From the obtained viscoelasticity curve, the storage modulus was determined at 30°C, 150°C, and 280°C, and the loss tangent (tanδ) was calculated from the loss modulus at each temperature. These were plotted and the point at which the tanδ curve reached its maximum was calculated. If multiple maximum points existed, the value closest to room temperature (23°C) was taken as the tanδ peak of the cured product. In Tables 2 to 4, for example, "1.0 x 10 6 The storage modulus value was recorded as "1.0E+06".

[0095] (Resin Flow) [Preparation of Evaluation Sample A] <<Manufacturing of thermosetting adhesive sheets with double-sided release films>> In the same manner as in the preparation of samples for measuring storage modulus and loss modulus, the coating liquids obtained in each Example and Comparative Example were used to obtain a thermosetting adhesive sheet with double-sided release film, in which both sides of a thermosetting adhesive sheet having a thickness of 25 μm after drying were covered with a 50 μm-thick heavy release film and a 50 μm-thick light release film, respectively. The light release film was peeled off from the thermosetting adhesive sheet with double-sided release film, and the exposed thermosetting adhesive sheet surface was temporarily adhered to Kapton 100H manufactured by DuPont Co., Ltd. Then, a circular hole with a diameter of 7 mm was formed using a punching machine. Next, the heavy release film was peeled off, and the exposed thermosetting adhesive sheet surface was temporarily bonded using a vacuum laminator to the copper foil on one side of a double-sided copper-clad laminate consisting of 12 μm copper foil laminated on both sides of a 50 μm polyimide film, and then thermally cured in a heat press at 180°C for 1 hour at 2 MPa to produce evaluation sample A.

[0096] [Evaluation method] For the evaluation sample A prepared as described above, a hole with a diameter of 7 mm was observed from the Kapton 100H side using an optical microscope (Keyence VHX-7000) at approximately 20 to 300 magnifications, and the length of the resin seeping out from the edge of the circle was measured and evaluated according to the following criteria. ◎: Resin flow is 100 μm or less. Extremely good results. ◯: Resin flow is greater than 100 μm and less than 150 μm. Good results. △: Resin flow is more than 150 μm to 200 μm or less, which is within the practical range. ×: Resin flow is over 200 μm. Not practical.

[0097] (Laser processability (before desmear solution treatment)) [Preparation of Evaluation Sample B] In the same manner as in the preparation of samples for measuring storage modulus and loss modulus, the coating liquids obtained in each Example and Comparative Example were used to obtain a thermosetting adhesive sheet with double-sided release film, in which both sides of a thermosetting adhesive sheet having a thickness of 25 μm after drying were covered with a 50 μm-thick heavy release film and a 50 μm-thick light release film, respectively. The light release film was peeled off from the thermosetting adhesive sheet with double-sided release film, and the exposed thermosetting adhesive sheet surface was temporarily adhered using a vacuum laminator to the copper foil on one side of a double-sided copper-clad laminate consisting of 12 μm copper foil laminated on both sides of a 50 μm polyimide film. Next, the heavy release film was peeled off, and a 50 μm thick polyimide film was applied to the exposed thermosetting adhesive sheet surface. The polyimide film side of a single-sided copper-clad laminate consisting of an imide film and a 12 μm copper foil was similarly temporarily bonded using a vacuum laminator, and then thermally cured in a heat press at 180°C for 1 hour at 2 MPa to obtain evaluation sample B with a laminate structure of copper foil 1 / polyimide film 2 / copper foil 1 / cured thermosetting adhesive sheet 3 / polyimide film 2 / copper foil 1.

[0098] [Evaluation method] Sample B was irradiated from above with a UV-YAG laser (Model 5330, manufactured by ESI) as shown in Figure 1, and a blind via hole with a diameter of 150 μm was drilled up to the boundary between the cured thermosetting adhesive sheet and the double-sided copper-clad laminate. Next, the cross section of the blind via was observed at a magnification of approximately 20 to 500 times using a laser microscope (Keyence VK-X100), and the maximum length of side etching (horizontal etching exceeding the designed opening diameter) that occurred in the cured thermosetting adhesive sheet was measured and evaluated according to the following criteria. ◎: 5 μm or less Very good results. ◯: Greater than 5 μm and less than 7 μm. Good results. △: More than 7 μm and 10 μm or less, within the practical range. ×: Larger than 10 μm, not practical.

[0099] (Laser processability (after desmear solution treatment)) A sample with a 150 μm diameter blind via drilled to the boundary between the cured thermosetting adhesive sheet and the double-sided copper-clad laminate was immersed in Macutizer 9221-S manufactured by Japan MacDermid Co., Ltd. for 7 minutes at 60°C, Macutizer 9275 for 7 minutes at 75°C, and Macutizer 9276 for 5 minutes at 45°C, then washed with a water shower at 23°C for 5 minutes and dried in an oven at 40°C for 10 minutes. Next, the cross section of the blind via was observed with a laser microscope (Keyence VK-X100) at a magnification of approximately 20 to 500 times, and the state of peeling at the boundary between the copper foil and the cured thermosetting adhesive sheet, and between the polyimide film and the cured thermosetting adhesive sheet, was evaluated. ⊚: Peeling occurred in 3 or fewer holes out of 30, which is an extremely good result. ◯: Peeling occurred in 4 to 6 holes out of 30 holes, which is a good result. △: Peeling occurred in 7 to 10 holes out of 30 holes, which is within the practical range. ×: Peeling occurred in 11 or more holes out of 30 holes. Unusable.

[0100] (Heat resistance) [Evaluation method] Sample B for evaluation was prepared and stored for at least 24 hours in an atmosphere of 23°C and 50% relative humidity, after which a solder float test was performed in which the sample was floated in molten solder at 288°C for 3 minutes. The cross section was then observed with a laser microscope (Keyence VK-X100) at magnifications of approximately 20 to 500 times, and the state of peeling at the boundary between the copper foil and the cured thermosetting adhesive sheet, and between the polyimide film and the cured thermosetting adhesive sheet, was evaluated. Thirty samples were evaluated. ⊚: Peeling rate is 10% or less, which is an extremely good result. ○: The number of peelings is more than 10% to 20% or less, which is a good result. △: The number of peeled holes is more than 20% to 30% or less, which is within the practical range. ×: The number of peeled holes exceeds 30%. Unusable.

[0101] (Cold and hot cycle resistance) Evaluation sample B was prepared and its thermal cycle characteristics were evaluated. The treatment conditions were 15 minutes at -30°C and 15 minutes at 150°C, with one cycle consisting of 2000 cycles. After 2000 cycles, the cross section was observed with a laser microscope (Keyence VK-X100) at a magnification of approximately 20 to 500 times. 30 evaluation samples were used. ⊚: The number of peelings was less than 10%, which is an extremely good result. ◯: The number of peelings is 10 to less than 20%, which is a good result. △: The number of peeled holes is less than 20% to 30%, which is within the practical range. ×: The number of peeled holes is 30% or more, and it is not practical.

[0102] (Impact absorption test) [Preparation of evaluation sample C] In the same manner as in the preparation of samples for measuring storage modulus and loss modulus, the coating liquids obtained in each Example and Comparative Example were used to obtain a thermosetting adhesive sheet with double-sided release film, in which both sides of a thermosetting adhesive sheet having a thickness of 25 μm after drying were covered with a 50 μm-thick heavy release film and a 50 μm-thick light release film, respectively. The light release film was peeled off from the thermosetting adhesive sheet with double-sided release films, and the exposed surface of the thermosetting adhesive sheet was temporarily adhered to a 3 mm thick float glass manufactured by Test Piece Co., Ltd. using a vacuum laminator. Next, the heavy release film was peeled off, and the polyimide film side of the single-sided copper-clad laminate, which consisted of a 50 μm polyimide film and a 12 μm copper foil laminated to the exposed thermosetting adhesive sheet surface, was similarly temporarily adhered using a vacuum laminator, and then thermally cured in a heat press at 180°C for 1 hour at 2 MPa to obtain evaluation sample C with a laminate structure of float glass / cured product / polyimide film / copper foil. [Evaluation method] Next, a 300g cone was dropped freely from a height of 20cm onto the test surface of the test piece (the side with the copper clad laminate on one side) with the tip pointing downwards. The float glass side of the test piece was visually inspected for cracks or traces of the cone, and rated according to the following criteria. Ten test samples were used. ⊚: No cracks or traces, an extremely good result. ○: 1 to 2 cracks and marks in total. Good results. △: 3 to 4 cracks and marks in total, within the practical range. ×: 5 or more cracks / marks in total. Not usable.

[0103] [Table 2]

[0104] [Table 3]

[0105] [Table 4] [Industrial Applicability]

[0106] The present invention provides a thermosetting resin composition that exhibits excellent laser processability, heat resistance, thermal cycle resistance, and impact absorption, and that exhibits minimal resin flow. These compositions are suitable for the production of various printed wiring boards, electronic devices, and other devices that require high processability and reliability. [Explanation of symbols]

[0107] 1 copper foil 2 Polyimide film 3. Cured thermosetting adhesive sheet 4 Side etching

Claims

1. A thermosetting adhesive sheet formed from a thermosetting resin composition, The thermosetting resin composition comprises a polyimide resin (A) (excluding high-softening-point polyimide resins having a softening point of 140°C or higher) which is a reaction product of a monomer group including a dimer diamine (a-1) and a tetracarboxylic acid anhydride (a-2); at least one curing agent (B) selected from the group consisting of epoxy compounds (B-1), maleimide compounds (B-2), isocyanate group-containing compounds (B-3), metal chelate compounds (B-4), and carbodiimide group-containing compounds (B-5); and a filler (C) (provided that the thermosetting resin composition does not contain a high-softening-point polyimide resin having a softening point of 140°C or higher, an imidazole curing accelerator, or an active ester-type curing agent), the molecular chain terminal of the polyimide resin (A) is an acid anhydride group, The curing agent (B) is contained in an amount of 3 to 20 parts by mass relative to 100 parts by mass of the polyimide resin (A), The filler (C) is boron nitride and / or a liquid crystal polymer; the cured product obtained by heating the thermosetting resin composition at 180°C for 60 minutes satisfies (i) to (iii), A thermosetting adhesive sheet having a thickness of 10 to 500 μm. (a) Storage modulus at 30°C is 1.0 x 10 ６ ~1.0 x 10 １１ It is Pa. (b) Storage modulus at 150°C is 1.0 x 10 ４ ~1.0 x 10 ９ It is Pa. (c) Storage modulus at 280°C is 1.0 x 10 ３ ~1.0 x 10 ９ It is Pa.

2. 2. The thermosetting adhesive sheet according to claim 1, wherein the cured product has a peak loss tangent (tan δ) of 0.3 or more at 0 to 280°C.

3. 3. The thermosetting adhesive sheet according to claim 1, wherein the curing agent (B) contains three or more reactive functional groups per molecule that can react with the polyimide resin (A).

4. 4. The thermosetting adhesive sheet according to claim 1, wherein the filler (C) is contained in an amount of 5 to 60 parts by mass per 100 parts by mass of the polyimide resin (A).

5. 5. The thermosetting adhesive sheet according to claim 1, which is used as an adhesive for joining layers of a printed wiring board.

6. The thermosetting adhesive sheet according to any one of claims 1 to 5, wherein the polyimide resin (A) has an acid value of 6 to 8 mgKOH / g.

7. A thermosetting cover sheet with a release film, comprising the thermosetting adhesive sheet according to any one of claims 1 to 6 and a release film.

8. A copper-clad laminate comprising a copper foil and an insulating film laminated together via an adhesive layer that is a cured product of the thermosetting adhesive sheet according to any one of claims 1 to 6.

9. A printed wiring board comprising the thermosetting adhesive sheet according to any one of claims 1 to 6.

10. An electronic device comprising the printed wiring board according to claim 9.

11. A cured product of the thermosetting adhesive sheet according to any one of claims 1 to 6, A cured product characterized by satisfying (a) to (c). (a) Storage modulus at 30°C is 1.0 x 10 ６ ~1.0 x 10 １１ It is Pa. (b) Storage modulus at 150°C is 1.0 x 10 ４ ~1.0 x 10 ９ It is Pa. (c) Storage modulus at 280°C is 1.0 x 10 ３ ~1.0 x 10 ９ It is Pa.

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