Thermosetting resin composition, and adhesive film, prepreg, resin-coated copper foil, build-up film, laminate and printed wiring board using the same

Abstract

To provide a thermosetting resin composition capable of giving a cured product having a good balance between dielectric properties and adhesive force and particularly excellent in desmear resistance (etching liquid resistance).SOLUTION: A thermosetting resin composition comprising (A) a maleimide compound having one or more hydrocarbon groups derived from a dimer acid skeleton in one molecule, (B) an epoxy resin having two or more epoxy groups in one molecule, (C) a phenol resin having a triazine ring, and (D) a curing accelerator, wherein a ratio (Ep / Ph) of the number of epoxy groups (Ep) in the epoxy resin of the component (B) to the number of phenolic hydroxyl groups (Ph) in the phenol resin of the component (C) satisfies the following formula (1): SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermosetting resin composition, and to an adhesive film, a prepreg, a resin-coated copper foil, a build-up film, and a printed wiring board using the same. [Background technology]

[0002] In recent years, the next-generation communication system known as 5G (millimeter-wave band, 26 GHz to 80 GHz) has become popular, and development of the next-generation communication system known as 6G has also begun. To realize communication systems with higher speeds, larger capacities, and lower latency than current systems, materials for the high-frequency band between 3 and 80 GHz are required, and reducing transmission loss is essential as a noise countermeasure. Transmission loss is the sum of conductor loss and dielectric loss. Reducing conductor loss requires reducing the surface roughness of the metal foil used, especially copper foil. Dielectric loss is proportional to the square root of the dielectric constant and the dielectric loss tangent. Therefore, insulating materials with excellent dielectric properties (low dielectric constant and low dielectric loss tangent) are required. Circuit board applications, in particular, require insulating materials with such excellent dielectric properties. A material known as reactive polyphenylene ether resin (PPE) has been used in rigid circuit boards. Furthermore, materials known as liquid crystal polymers (LCPs) and modified polyimides (MPIs) have been used in flexible printed circuit boards (FPCs).

[0003] In response to this, it has been reported that maleimide compounds (special maleimide compounds) essentially having a dimer diamine skeleton are used as the main resin for substrates (Patent Documents 1 and 2). Contrary to the properties of typical maleimide resins, special maleimide compounds have properties such as a low glass transition temperature (Tg) and a high coefficient of thermal expansion (CTE). Furthermore, compared to conventional thermosetting resins, they also have excellent dielectric properties and flexibility. Furthermore, they have many advantages, such as superior adhesion to metals and other materials compared to epoxy resins, and the fact that they are thermosetting resins allows for the possibility of (high) multilayering, and they have been the subject of extensive research and development.

[0004] On the other hand, from the viewpoint of dimensional stability of the substrate, it has been reported that special maleimide compounds are used in combination with other aromatic maleimide compounds with high Tg (Patent Documents 3 to 5). However, aromatic maleimide compounds not only tend to have poor dielectric properties in the millimeter-wave region above 28 GHz, but also have problems such as being prone to moisture absorption, poor compatibility, prone to separation in the cured product, and prone to quality variation. In contrast, it has been found that a method for increasing the Tg of special maleimide compounds themselves can be achieved by using maleimide compounds in combination with diamines other than dimer diamine (Patent Document 6). Furthermore, it has become possible to obtain well-balanced compositions by combining multiple types of special maleimide compounds (Patent Documents 7 and 8). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2016 / 114287 [Patent Document 2] Japanese Patent Application Publication No. 2018-201024 [Patent Document 3] International Publication No. 2016 / 114286 [Patent Document 4] JP 2018-12764 A [Patent Document 5] JP 2018-12772 A [Patent Document 6] Japanese Patent Application Publication No. 2019-203122 [Patent Document 7] Japanese Patent Application Laid-Open No. 2023-67339 [Patent Document 8] Japanese Patent Application Publication No. 2023-67340 Summary of the Invention [Problem to be solved by the invention]

[0006] However, as we have studied these materials in more detail, we have also found other issues. For example, there are differences even among curing systems. Radical-curing systems have excellent dielectric properties but somewhat lower adhesive strength and tend to have reduced long-term reliability. On the other hand, anionic polymerization systems have high adhesive strength but somewhat inferior dielectric properties and tend to have lower storage stability than radical-curing systems. Furthermore, as mentioned above, the problem of decreased adhesive strength as the copper foil surface roughens is already known, and this is not an issue unique to compositions containing special maleimide compounds. Perhaps as a result, when removing smears during the wet desmear process after via formation, the etching solution penetrates deeper into the interface between the resin and copper foil, making the resin more likely to peel from the copper foil. A relatively simple anionic polymerization system consisting of a special maleimide compound and an epoxy resin has very high adhesive strength, but peeling during this wet desmear process presents an issue.

[0007] Therefore, an object of the present invention is to provide a composition that can give a cured product that has a good balance between dielectric properties and adhesive strength and is particularly excellent in desmear resistance (etchant resistance), as well as adhesive films, prepregs, resin-coated copper foils, and build-up films that contain the composition, laminates made using them, and printed wiring boards made from laminates. [Means for solving the problem]

[0008] As a result of extensive research to solve the above problems, the present inventors have found that the following thermosetting resin can achieve the above object, and have completed the present invention.

[0009] [1] (A) A maleimide compound having one or more hydrocarbon groups derived from a dimer acid skeleton in one molecule. (B) Epoxy resin having two or more epoxy groups in one molecule (C) a phenolic resin having a triazine ring, and (D) Curing accelerator wherein the ratio (Ep / Ph) of the number of epoxy groups (Ep) in the epoxy resin of component (B) to the number of phenolic hydroxyl groups (Ph) in the phenol resin of component (C) satisfies the following formula (1):

number

[10] A laminate having the adhesive film according to [6].

[11] A laminate having the prepreg according to [7].

[12] [8] A laminate having a resin-coated copper foil according to [8].

[13] A laminate having the build-up film according to [9].

[14] A printed wiring board comprising one or more laminates according to any one of

[10] to

[13] . [Effects of the Invention]

[0010] The thermosetting resin composition of the present invention can provide a cured product that has a good balance between dielectric properties and adhesive strength and is particularly excellent in desmear resistance (etchant resistance). Furthermore, adhesive films, prepregs, resin-coated copper foils, and build-up films containing the composition can be produced, as well as laminates made from these and printed wiring boards made by processing laminates, and these compositions are particularly useful for high-speed communication applications. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in more detail below.

[0012] (A) A maleimide compound having one or more hydrocarbon groups derived from a dimer acid skeleton in one molecule. The component (A) used in the present invention is a maleimide compound having one or more hydrocarbon groups derived from a dimer acid skeleton per molecule. Because the component (A) has a hydrocarbon group derived from a dimer acid skeleton, the cured product of a composition containing the component (A) has a low dielectric constant and dielectric loss tangent, and also exhibits excellent film properties and handleability after curing. Furthermore, because the component (A) has an imide group, the composition containing the component (A) has high insulating properties even when formed into a film (thin film). In addition to the hydrocarbon group derived from the dimer acid skeleton, the component (A) may also contain a hydrocarbon group derived from a trimer acid skeleton.

[0013] The maleimide compound of component (A) preferably contains at least one, and preferably two or more, of the maleimide compounds represented by formulas (2), (3), and (4), and at least one of the maleimide compounds represented by formulas (2), (3), and (4) is a solid at 25° C. By containing such a solid maleimide compound, the uncured resin layer has excellent film properties and reduced tackiness, thereby improving the handleability of the film, resin-coated copper foil, and prepreg.

[0014] [ka] (In formula (2), A's independently represent tetravalent organic groups having a cyclic structure; B's independently represent divalent hydrocarbon groups having 6 to 60 carbon atoms, provided that the group does not include groups having a dimer acid skeleton; D's independently represent groups selected from divalent aliphatic hydrocarbon groups and divalent aromatic hydrocarbon groups having 6 to 60 carbon atoms, at least one of which is a hydrocarbon group derived from a dimer acid skeleton; m1 represents an integer of 1 to 100; and m2 represents an integer of 1 to 200. The order of the repeating units bracketed by m1 and m2 is not limited, and the bonding pattern may be alternating, block, or random.)

[0015] [ka] (In formula (3), A's are independently tetravalent organic groups having a cyclic structure, D's are independently groups selected from divalent aliphatic hydrocarbon groups and divalent aromatic hydrocarbon groups having 6 to 60 carbon atoms, and at least one of the D's is a hydrocarbon group derived from a dimer acid skeleton. n is 1 to 100.)

[0016] [ka] (In formula (4), D represents a hydrocarbon group derived from a dimer acid skeleton.)

[0017] Furthermore, among the skeletons derived from dimer acid and trimer acid, it is preferable to use one having a high purity of dimer acid, with a ratio of dimer acid of 95% by mass or more, because this has excellent dielectric properties, tends to have a low viscosity when heated, is excellent in formability, and tends to be less affected by moisture absorption.

[0018] The dimer acid referred to here is a liquid dibasic acid primarily composed of a 36-carbon dicarboxylic acid, produced by dimerization of an 18-carbon unsaturated fatty acid derived from natural sources such as vegetable oils. Dimer acids do not have a single skeleton but rather have multiple structures, resulting in multiple isomers. Representative dimer acids are classified as linear (a), monocyclic (b), aromatic (c), and polycyclic (d). In this specification, the dimer acid skeleton refers to a group derived from a dimer diamine having a structure in which the carboxy groups of such a dimer acid are substituted with primary aminomethyl groups. In other words, the dimer acid skeleton of component (A) is preferably a group in which two carboxy groups in each of the dimer acids shown below (a) to (d) are substituted with methylene groups.

[0019] Furthermore, from the viewpoint of the heat resistance and reliability of the cured product, it is more preferable that the hydrocarbon group derived from the dimer acid skeleton in the maleimide compound of component (A) has a structure in which the carbon-carbon double bond in the hydrocarbon group derived from the dimer acid skeleton is reduced by a hydrogenation reaction.

[0020] [ka]

[0021] As described above, the dimer acid skeleton has multiple structures, and therefore, in this specification, the hydrocarbon group derived from the dimer acid skeleton is simply referred to as -C 36 H 70 It may be written as -.

[0022] Furthermore, trimer acid here is essentially a by-product generated during the synthesis of dimer acid. Trimer acid is a tribasic acid whose main component is a 54-carbon tricarboxylic acid, produced from the trimer of an 18-carbon unsaturated fatty acid derived from natural sources such as vegetable oils. Like dimer acid, trimer acid does not have a single skeleton but rather has multiple structures, resulting in the existence of multiple isomers.

[0023] First, although the maleimide compound represented by formula (2) has a high melt viscosity before curing, it has superior dielectric properties compared to typical maleimide compounds containing many aromatic groups. Furthermore, it has high adhesion to copper foil, absorbs less moisture than typical thermosetting resins such as epoxy resins, and is less affected by moisture. Furthermore, it has a higher Tg and a smaller coefficient of thermal expansion (CTE) than the maleimide compound represented by formula (3), resulting in a highly reliable composition.

[0024] In addition, in the formula (2), A independently represents a tetravalent organic group having a cyclic structure, and among these, it is preferable that A is any of the tetravalent organic groups represented by the following formulas. [ka] (The bond not bonded to a substituent in the above structural formula is bonded to the carbonyl carbon that forms the cyclic imide structure in formulas (2) and (3).)

[0025] In the formula (2), D's are independently selected from divalent aliphatic hydrocarbon groups and divalent aromatic hydrocarbon groups having 6 to 60 carbon atoms, preferably 8 to 60 carbon atoms, and more preferably 10 to 55 carbon atoms. Among these, the divalent alicyclic hydrocarbon group is preferably a branched divalent alicyclic hydrocarbon group in which one or more hydrogen atoms are substituted with an alkyl or alkenyl group having 6 to 60 carbon atoms, preferably 8 to 60 carbon atoms, and more preferably 10 to 55 carbon atoms. The branched divalent alicyclic hydrocarbon group may be either a saturated aliphatic hydrocarbon group or an unsaturated hydrocarbon group, and may have an alicyclic structure or an aromatic ring structure in the middle of the molecular chain.

[0026] Specific examples of the group selected from the divalent aliphatic hydrocarbon group and the divalent aromatic hydrocarbon group include the divalent alicyclic hydrocarbon group derived from the diamine at both ends, called dimer diamine, and one or more hydrocarbon groups in one molecule have this dimer acid skeleton-derived hydrocarbon group.

[0027] In the formula (2), B's are independently divalent hydrocarbon groups having 6 to 60 carbon atoms. In particular, B's are independently divalent aliphatic hydrocarbon groups having 6 to 60 carbon atoms or aromatic hydrocarbon groups having 6 to 60 carbon atoms. Preferably, B's are divalent aliphatic hydrocarbon groups or aromatic hydrocarbon groups having 6 to 30 carbon atoms. The divalent hydrocarbon groups may have a cyclic structure or a branched structure, but do not include groups having a dimer acid skeleton, such as those in D. The divalent aromatic hydrocarbon groups may have a bond directly to the aromatic ring, or may be connected to the aromatic ring via a linear or branched divalent aliphatic hydrocarbon group. Specific examples of B include divalent hydrocarbon groups represented by the following structural formula: [ka]

[0028] In the formula (2), m1 is 1 to 100, preferably 1 to 60, and more preferably 2 to 50. m2 is 1 to 200, preferably 1 to 100, more preferably 1 to 50, and even more preferably 1 to 40. In particular, it is preferable that m1+m2 is in the range of 2 to 40 from the viewpoints of the fluidity and moldability of the composition, the strength of the cured product, etc. On the other hand, if m1+m2 is greater than 40, the fluidity may decrease, and moldability may be poor.

[0029] The order of the repeating units bounded by m1 and m2 is not limited, and the bonding pattern may be alternating, block, or random, but among these, block bonding is preferred from the viewpoint of facilitating a high Tg.

[0030] Next, the maleimide compound represented by the formula (3) has superior dielectric properties to other common maleimide compounds containing many aromatic groups. In particular, it is not only effective in maintaining dielectric properties even at high frequencies, but also has stronger adhesion to copper foil and other resins than the compound represented by the formula (2), resulting in an excellent composition.

[0031] In the formula (3), A independently represents a tetravalent organic group having a cyclic structure, and preferred examples thereof are the same as those exemplified in the formula (2). D independently represents a group selected from divalent aliphatic hydrocarbon groups and divalent aromatic hydrocarbon groups having 6 to 60 carbon atoms, and preferred examples thereof are the same as those exemplified in the formula (2).

[0032] In the formula (3), n is 1 to 100, preferably 1 to 60, and more preferably 1 to 50. If n is too large, the solubility and flowability may decrease, and moldability may be poor.

[0033] Next, the maleimide compound represented by the above formula (4) has superior dielectric properties compared to other common maleimide compounds containing many aromatic groups. It is particularly effective in maintaining dielectric properties even at high frequencies. Furthermore, because it is a liquid at room temperature, it has the effect of improving the moldability of the resin composition of the present invention and improving handling properties, such as film properties before curing.

[0034] Therefore, when using the maleimide compound represented by formula (4), it is preferable to use it in combination with one or more of the maleimide compounds represented by formula (2) and formula (3).

[0035] The viscosity of the maleimide compound represented by formula (4) is preferably in the range of 1.0 to 5.0 Pa s as measured at 25°C and 5 rpm using a cone-and-plate rotational viscometer in accordance with JIS Z 8803:2011.

[0036] Among the maleimide compounds of component (A), the number-average molecular weight of the maleimide compounds represented by formula (2) and formula (3) is not particularly limited, but from the viewpoint of the handleability of the composition, it is preferably 1,500 to 50,000, more preferably 2,000 to 30,000. Furthermore, component (A) may contain not only the maleimide compound represented by formula (2), (3), or (4) but also other maleimide compounds having one or more hydrocarbon groups derived from a dimer acid skeleton per molecule, and these maleimide compounds may be used alone or in combination, but as described above, when a maleimide compound represented by formula (4) is used, it is preferable that at least one of formula (2) or formula (3) is included.

[0037] The number average molecular weight (Mn) referred to in the present invention refers to the number average molecular weight measured by gel permeation chromatography (GPC) under the following conditions using polystyrene as a standard substance.

[0038] [Measurement conditions] Developing solvent: tetrahydrofuran (THF) Flow rate: 0.35mL / min Detector: Refractive index detector (RI) Column: TSK Guardcolumn SuperH-L TSKgel SuperHZ4000(4.6mmI.D.×15cm×1) TSKgel SuperHZ3000(4.6mmI.D.×15cm×1) TSKgel SuperHZ2000 (4.6mmI.D.×15cm×2) (All manufactured by Tosoh Corporation) Column temperature: 40℃ Sample injection volume: 5 μL (0.2% by mass THF solution)

[0039] The component (A) may be used alone or in combination of two or more types. The content of component (A) in the composition of the present invention is preferably from 10 to 99 mass %, more preferably from 20 to 95 mass %, and particularly preferably from 30 to 90 mass %.

[0040] (B) Epoxy resin having two or more epoxy groups in one molecule The thermosetting cyclic resin composition of the present invention contains, as component (B), an epoxy resin having two or more epoxy groups per molecule. By blending the epoxy resin into the composition, it is possible to increase the adhesive strength of the resin composition of the present invention and improve other mechanical properties.

[0041] In consideration of reactivity, storage stability, etc., component (B) is preferably an epoxy resin having a glycidyl group.

[0042] Examples of component (B) include phenol novolac type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenol type epoxy resins, naphthalene type epoxy resins, anthracene type epoxy resins, naphthol type epoxy resins, xylylene type epoxy resins, biphenyl type epoxy resins, biphenyl aralkyl type epoxy resins, triphenylmethane type epoxy resins, alicyclic type epoxy resins, glycidylamine type epoxy resins, dicyclopentadiene type epoxy resins, stilbene type epoxy resins, sulfur atom-containing epoxy resins, and phosphorus atom-containing epoxy resins. From the viewpoints of compatibility and wettability with the substrate, it is preferable that component (B) be liquid at room temperature (25°C).

[0043] The amount of component (B) is preferably 0.05 to 20 parts by mass, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the thermosetting resin components consisting of components (A), (B), and (C) described below. Within this range, the curing speed during molding is appropriate, the heat resistance and moisture resistance of the resulting cured product are well balanced, and the desired low dielectric properties are also achieved.

[0044] The epoxy resin of component (B) may be used alone or in combination of two or more.

[0045] (C) Phenolic resin having a triazine ring The component (C) used in this invention is a phenolic resin having a triazine ring. This phenolic resin is generally used as a curing agent for epoxy resins. Maleimide compounds cure through a polymerization reaction called anionic polymerization, driven by active species generated by the reaction of epoxy resin with an anionic polymerization initiator (described below). This anionic polymerization produces cured products with high adhesive strength and reliability. By using a phenolic resin having a triazine ring as component (C) in this polymerization reaction, not only anionic polymerization but also polymerization driven by a Michael addition reaction is added, which primarily improves the mechanical properties of the cured product. Furthermore, the component (C) has a triazine skeleton, which improves resistance to the etching solution used in the wet desmear process.

[0046] The (C) phenolic resin having a triazine ring is preferably one represented by the following formula (5). [ka] (In formula (5), R is independently a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms, and x is 1 to 30.)

[0047] In formula (5), R is independently a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms, and may be linear or branched. However, from the viewpoint of availability of raw materials, R is preferably a hydrogen atom or a methyl group. x is 1 to 30, but from the viewpoint of compatibility, x is preferably in the range of 1 to 20.

[0048] As component (C), commercially available products can be used, such as LA-7052, LA-7054, LA-1356, and LA-3018-50P (all manufactured by DIC Corporation).

[0049] Component (C) is preferably blended in an amount of 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, based on 100 parts by mass in total of the thermosetting resin composed of components (A), (B) and (C). At this time, the ratio (Ep / Ph) of the number of epoxy groups (Ep) in the epoxy resin of component (B) to the number of phenolic hydroxyl groups (Ph) in the phenolic resin of component (C) satisfies the following formula (1).

Number

[0050] (D) Curing accelerator Component (D) is a curing accelerator for accelerating the curing reaction of the thermosetting resin of the present invention. It is added to initiate and accelerate the crosslinking reaction of the maleimide compound as component (A) and the reaction between the maleimide group in component (A) and a reactive group capable of reacting therewith. Examples of the curing accelerator include a thermal radical polymerization initiator and an anionic polymerization initiator.

[0051] The thermosetting resin composition of the present invention can contain not only the maleimide compound of component (A), but also an epoxy resin of component (B), a phenolic resin of component (C), and, as an optional component described below, other thermosetting resins having reactive groups capable of reacting with maleimide groups. Therefore, it is preferable to use an anionic polymerization catalyst such as an imidazole compound, a tertiary amine compound, or an organic phosphorus compound. Examples of the anionic polymerization catalyst include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, and 2-phenyl-4,5-dihydroxymethylimidazole. imidazole compounds such as 2-phenyl-4-methyl-5-hydroxymethylimidazole; tertiary amine compounds such as triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 1,8-diazabicyclo[5.4.0]undecene, and tris(dimethylaminomethyl)phenol; and organophosphorus compounds such as tributylphosphine, tri(p-methylphenyl)phosphine, tri(nonylphenyl)phosphine, triphenylphosphine, triphenylphosphine oxide, triphenylphosphine-triphenylborane, and tetraphenylphosphine-tetraphenylborate.

[0052] Examples of the anionic polymerization catalyst include the above-mentioned imidazole compounds, tertiary amine compounds and organic phosphorus compounds, with imidazole compounds being particularly preferred. The catalyst of component (D) may be used alone or in combination of two or more different types.

[0053] The amount of component (D) is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the thermosetting resin component consisting of components (A), (B), and (C). A content within the above range is preferred because the curing property is stable during molding of the thermosetting resin film of the present invention. Furthermore, the resulting cured product has a good balance of heat resistance and moisture resistance.

[0054] Other additives The thermosetting resin composition of the present invention may further contain various additives as required. Examples of other additives are listed below.

[0055] (E) Inorganic filler The thermosetting resin composition of the present invention may further contain (E) an inorganic filler. The inorganic filler is blended for the purposes of increasing the strength and rigidity of the cured product of the thermosetting resin composition of the present invention, or adjusting the thermal expansion coefficient and dimensional stability of the cured product. As the inorganic filler, those blended in conventional epoxy resin compositions or silicone resin compositions can be used, but silica particles such as spherical silica, fused silica, and crystalline silica, or boron nitride are preferred so as not to increase the dielectric constant of the entire composition.

[0056] The average particle size and shape of the inorganic filler are not particularly limited, but from the viewpoint of the processability of the substrate, spherical silica having an average particle size of 0.5 to 5 μm is preferably used. The average particle size is the mass average particle size D 50 (or median diameter).

[0057] Furthermore, in order to improve the properties of the inorganic filler, it is preferable that the surface of the filler is treated with a silane coupling agent having an organic group capable of reacting with a maleimide group, an epoxy group, and a phenol group, such as an epoxy group-containing alkoxysilane, an amino group-containing alkoxysilane, a (meth)acrylic group-containing alkoxysilane, or an alkenyl group-containing alkoxysilane.

[0058] As the silane coupling agent, a (meth)acrylic group- and / or amino group-containing alkoxysilane is preferably used, and specific examples thereof include 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane.

[0059] The inorganic filler may be used alone or in combination of two or more. Since it is an optional component, it may or may not be added, but when an inorganic filler is added, the amount added is preferably 30 to 500 parts by mass, and more preferably 30 to 400 parts by mass, per 100 parts by mass of the total of the thermosetting resin components consisting of components (A), (B), and (C).

[0060] Thermosetting resin having a reactive group capable of reacting with a maleimide group In the present invention, a thermosetting resin having a reactive group capable of reacting with the maleimide group of component (A), the epoxy group of component (B), and the phenolic hydroxyl group of component (C) may also be added.

[0061] Examples of thermosetting resins that can be blended include various resins other than components (A) to (C), such as melamine resins, silicone resins, cyclic imide resins including maleimide compounds other than component (A), urea resins, thermosetting polyimide resins, modified polyphenylene ether resins, thermosetting acrylic resins, etc. Furthermore, phenolic curing agents, amine curing agents, acid anhydride curing agents, and active ester curing agents other than component (C), which are used as curing agents for epoxy resins, are also included in thermosetting resins.

[0062] However, it is preferable to select the thermosetting resin to be used taking into consideration the curing system. The amount of the thermosetting resin to be added is preferably 0 to 30 mass %, and more preferably 2 to 10 mass %, of the total amount of the thermosetting resin.

[0063] others In addition to the above, the thermosetting resin composition of the present invention may contain non-functional silicone oil, reactive diluent, thermoplastic resin, thermoplastic elastomer, organic synthetic rubber, photosensitizer, light stabilizer, polymerization inhibitor, flame retardant, pigment, dye, adhesion aid, ion trapping material, etc. In this case, a silane coupling agent may be added as an adhesion aid separately from the inorganic filler treatment.

[0064] The thermosetting resin composition of the present invention can also be dissolved in an organic solvent and treated as a varnish or slurry. Forming the composition into a varnish facilitates film formation and facilitates coating and impregnation of glass cloth made of E-glass, low-dielectric glass, quartz glass, and the like. Any organic solvent can be used as long as it dissolves the thermosetting resins (A), (B), and (C) and other additives having reactive groups capable of reacting with maleimide groups. Examples of such organic solvents include anisole, tetralin, mesitylene, xylene, toluene, tetrahydrofuran (THF), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetonitrile. Among these, aromatic organic solvents such as anisole, tetralin, mesitylene, xylene, and toluene are preferred. Low-molecular-weight ketone solvents such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK) are also commonly used in preparing varnishes and slurries, but the maleimide compound (A) used in the present invention has low solubility in these ketone solvents, and their use may be undesirable. These organic solvents may be used alone or in combination of two or more.

[0065] The thermosetting resin composition of the present invention can be produced by mixing the components (A), (B), (C), and (D), as well as other additives that may be added as needed, using, for example, a planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.) or a THINKY CONDITIONING MIXER (manufactured by THINKY CORPORATION).

[0066] This thermosetting resin composition can be formed into an uncured resin sheet or film by applying the varnish to a substrate and then volatilizing the organic solvent, and then curing the uncured resin sheet or film. Examples of methods for producing the sheet and film are given below, but the present invention is not limited to these.

[0067] For example, a thermosetting resin composition (varnish) dissolved in an organic solvent is applied to a substrate, typically heated at 80°C or higher, preferably 100°C or higher, for 0.5 to 20 minutes to remove the organic solvent, followed by further heating at 130°C or higher, preferably 150°C or higher, for 0.5 to 10 hours, resulting in the formation of a flat, strong cured resin coating. The temperatures in the drying step to remove the organic solvent and the subsequent heat-curing step may each be constant, but it is preferable to increase the temperature stepwise. This allows the organic solvent to be efficiently removed from the composition and the resin curing reaction to proceed efficiently. Methods for applying the varnish include, but are not limited to, a spin coater, slit coater, spray, dip coater, bar coater, and the like.

[0068] The substrate can be a general resin substrate, such as polyolefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, and polystyrene (PS) resin, and polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polycarbonate (PC) resin. The surface of the substrate may be subjected to a release treatment. The thickness of the coating layer is not particularly limited, but the thickness after solvent removal is in the range of 1 to 200 μm, preferably 3 to 150 μm. A cover film may also be used on the coating layer. Alternatively, the components may be premixed and extruded into a sheet or film using a melt kneader, and then used as is.

[0069] The film obtained in this manner can be used as an adhesive film or build-up film. The adhesive film can be used between a core material and a coverlay film to produce a flexible printed wiring board, or between an organic substrate and a build-up film. Build-up films are used in the semi-additive process (SAP) and its improved method (M-SAP) for producing laminates and printed wiring boards. In this invention, bonding films are also called adhesive films and are used to bond organic substrates to build-up films or copper foils. Build-up films are also called interlayer insulating materials and are used as insulating layers for organic substrates and glass substrates.

[0070] Here, copper foil is used as the substrate, and an uncured or semi-cured film can be formed on the copper foil in the same manner as above to produce a resin-coated copper foil. Alternatively, as described above, a thermosetting resin can be dissolved in an organic solvent to form a varnish, which is then applied to a release-treated polyethylene terephthalate (PET) film, the solvent is dried to produce a film, and the film is then attached to the copper foil, after which the PET film is peeled off to obtain a resin-coated copper foil. The lamination conditions are not particularly limited, but lamination is preferably performed at a heating temperature of 80 to 130°C, under 0.1 to 1.0 MPa, and for 0.5 to 5 minutes.

[0071] There are no particular limitations on the roughness of the copper foil used, but from the perspective of reducing conductor loss, it is preferable to use a copper foil with a ten-point average roughness (Rz) of 1.5 μm or less on the surface of the copper foil that is in contact with the uncured or semi-cured thermosetting resin. A small Rz is sufficient to reduce conductor loss, preferably 1.3 μm or less, and more preferably 1.0 μm or less. On the other hand, materials with a small Rz tend to have a low anchoring effect and reduced adhesive strength. However, the thermosetting resin composition of the present invention has high adhesive strength and can be used with copper foils with such low roughness.

[0072] The copper foil to be used may be produced by any method, but is generally produced by electrolysis or rolling, and electrolytic copper foil produced by electrolysis is often used. The copper foil to be used may be surface-treated to improve adhesive strength, heat resistance, chemical resistance, etc.

[0073] There are no particular restrictions on the thickness of the copper foil, but foils in the range of 6 to 50 μm are commonly used. Thinner foils can be used in a form called carrier-attached copper foil. This is a method in which a carrier is attached to thin copper foil to improve handling, and the foil is thickened and the carrier is then peeled off in a subsequent process.

[0074] Alternatively, the varnished thermosetting resin composition can be impregnated into a fiber substrate such as glass cloth made from E-glass, low-dielectric glass, or quartz glass, and the organic solvent removed to create a semi-cured prepreg. Furthermore, by laminating the prepreg with copper foil, it is possible to produce multi-layered laminates and printed wiring boards.

[0075] The prepreg comprises a thermosetting resin and a fiber substrate. The thermosetting resin is the thermosetting resin composition or a semi-cured product of the resin composition. A semi-cured product is a resin composition that has been partially cured to the extent that it can be further cured. In other words, a semi-cured product is a resin composition that has been semi-cured, or in other words, a B-staged resin. On the other hand, an uncured state is sometimes referred to as an A-stage. That is, the thermosetting resin 2 may be the thermosetting resin composition in an A-stage state or the thermosetting resin composition in a B-stage state. As mentioned above, the fiber substrate can be made of E-glass, low-dielectric glass, quartz glass, S-glass, T-glass, or the like. While the type of glass used is not critical, quartz glass cloth, which has low dielectric properties, is preferred in order to take advantage of the properties of the thermosetting resin composition. The thickness of a commonly used fiber substrate is, for example, 0.01 mm or more and 0.3 mm or less.

[0076] When producing a prepreg, the thermosetting resin is preferably in the form of a varnish, as described above, for impregnation into a fiber substrate, which is the base material for forming the prepreg. Examples of methods for producing a prepreg include impregnating a fiber substrate with a thermosetting resin composition prepared in a varnish form and then drying the resulting mixture. The thermosetting resin is impregnated into the fiber substrate by immersion, coating, or the like. Impregnation can be repeated multiple times as needed. Furthermore, by repeating the impregnation process using multiple resin compositions with different compositions and concentrations, it is possible to adjust the final composition and impregnation amount to the desired level. The fiber substrate impregnated with the resin composition (resin varnish) is heated under the desired heating conditions, for example, at 80°C to 180°C for 1 minute to 20 minutes. Heating produces a prepreg containing an A-stage or B-stage thermosetting resin. The heating can volatilize the organic solvent from the varnish, thereby reducing or eliminating the organic solvent.

[0077] A laminate according to one embodiment of the present invention is a laminate comprising an insulating layer containing a cured product of the thermosetting resin composition or an insulating layer consisting of a cured product of the thermosetting resin composition, and a layer other than the insulating layer. A commonly known laminate is a metal-clad laminate. A metal-clad laminate comprises an insulating layer containing or consisting of a cured product of the thermosetting resin composition, and metal foil on both sides of the insulating layer. A single-sided metal-clad laminate may also be provided with metal foil on only one side of the insulating layer. The insulating layer may also be a cured product of the thermosetting resin composition, a cured product of the prepreg described above, or a laminate of multiple cured prepregs. A copper-clad laminate may also be prepared using resin-coated copper foil, or a metal-clad laminate may be prepared by first preparing a cured prepreg and then laminating a metal foil between the cured prepregs via a bonding film consisting of the thermosetting resin composition.

[0078] The method for producing such a laminate is not particularly limited as long as it is a common method, and examples thereof include a method in which, when prepreg is used, one or more prepreg sheets are stacked, and then a metal foil such as a copper foil is placed on either or both of the upper and lower surfaces of the prepreg sheets, and the stacked sheets are molded under heat and pressure to form an integrated laminate.

[0079] A printed wiring board according to one embodiment of the present invention comprises a cured product of the thermosetting resin composition. As described above, the insulating layer of the metal-clad laminate used in producing the printed wiring board may be produced using the prepreg described above. The printed wiring board can be produced by subjecting the metal-clad laminate to circuit formation processing such as drilling, metal plating, and metal foil etching, and multi-layer adhesive processing, using known methods.

[0080] When manufacturing a printed wiring board, the following steps may be further carried out: (1) drilling holes in the insulating layer, (2) roughening the insulating layer, and (3) forming a conductor layer. These steps (1) and (3) may be carried out according to various known methods used in manufacturing printed wiring boards.

[0081] Step (1) is a step of drilling holes in the insulating layer, thereby forming holes such as via holes and through holes in the insulating layer. Step (1) can be performed using, for example, a drill, a laser, plasma, or the like, depending on the composition of the resin composition used to form the insulating layer. The dimensions and shape of the holes depend on the design of the printed wiring board.

[0082] Step (2) is a step of roughening the insulating layer. The insulating layer is roughened while removing (desmearing) the remaining resin, called smear, generated in step (1). The roughening procedure and conditions are not particularly limited, and known procedures and conditions used for forming insulating layers of printed wiring boards can be used. For example, the insulating layer can be roughened by performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order.

[0083] The swelling liquid used in the roughening treatment is not particularly limited, but examples thereof include alkaline solutions and surfactant solutions, with alkaline solutions being preferred. These may be commercially available solutions, and examples of commercially available swelling liquids include "Swelling Dip Securigans P," "Swelling Dip Securigans SBU," and "Swelling Dip Securigant P" manufactured by Atotech Japan. The swelling treatment using the swelling liquid is not particularly limited, but can be performed by, for example, immersing the insulating layer in a swelling liquid at 30 to 90°C for 1 to 20 minutes. From the viewpoint of suppressing swelling of the resin in the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling liquid at 40 to 80°C for 5 to 15 minutes.

[0084] The oxidizing agent used in the roughening treatment is not particularly limited, but examples include alkaline permanganate aqueous solutions prepared by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. Roughening treatment using an oxidizing agent such as alkaline permanganate aqueous solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60 to 100°C for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate aqueous solution is preferably 5 to 10% by mass. These solutions can be commercially available, and examples of commercially available oxidizing agents include alkaline permanganate aqueous solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

[0085] This oxidizing agent dissolves the smear, but it also dissolves the resin layer itself, which is not smeared. As mentioned above, if the metal surface has a low roughness, when the oxidizing agent begins to dissolve the resin layer, the solution penetrates into the interface between the metal and resin layer, tending to easily peel off, so resistance to these oxidizing agents is necessary. On the other hand, if the resistance to these oxidizing agents is too high, problems occur in which desmearing is not possible, so simply having high resistance is not enough. The resin needs to have moderate oxidizing agent resistance, adhesive strength to prevent the solution from penetrating the interface, and wettability to the metal.

[0086] The neutralizing solution used in the roughening treatment is preferably an acidic aqueous solution, and a commercially available product such as "Reduction Solution Securigant P" manufactured by Atotech Japan can be cited. Treatment with a neutralizing solution can be carried out by immersing the surface that has been roughened with an oxidizing agent in a neutralizing solution at 30 to 80°C for 1 to 30 minutes. From the standpoint of workability, a preferred method is to immerse the object that has been roughened with an oxidizing agent in a neutralizing solution at 40 to 70°C for 5 to 20 minutes.

[0087] Step (3) is a step of forming a conductor layer, and the conductor layer is formed on the insulating layer. The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among these, from the viewpoints of versatility in forming the conductor layer, cost, ease of patterning, etc., a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferred, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

[0088] The conductor layer may have a single layer structure or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor layer has a multi-layer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of a nickel-chromium alloy. The thickness of the conductor layer depends on the desired design of the printed wiring board, but is generally 3 to 35 μm, preferably 5 to 30 μm. The conductor layer may also be formed by plating. [Example]

[0089] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these. Of the components (A) and (C) below, (A-1), (C-1), and (C-2) are commercially available in the form of varnish. In this example, the varnish solvent was removed in advance and then blended.

[0090] (A) Maleimide compound (A-1): A hydrocarbon group-containing bismaleimide compound derived from a dimer acid skeleton represented by the following formula (SLK-2600, manufactured by Shin-Etsu Chemical Co., Ltd., solid at 25°C) Number average molecular weight: 7,500 [ka] (A-2): A hydrocarbon group-containing bismaleimide compound derived from a dimer acid skeleton represented by the following formula (trade name: BMI-3000J, manufactured by Designer Molecules Inc., solid at 25°C) Number average molecular weight: 6,600 [ka] (A-3): A hydrocarbon group-containing bismaleimide compound derived from a dimer acid skeleton represented by the following formula (trade name: BMI-1500, manufactured by Designer Molecules Inc., syrup-like at 25°C) Number average molecular weight: 2,200 [ka] (A-4): A hydrocarbon group-containing bismaleimide compound derived from a dimer acid skeleton represented by the following formula (trade name: BMI-689, manufactured by Designer Molecules Inc., liquid at 25°C) Number average molecular weight: 950 [ka] (A-5): 4,4'-diphenylmethane bismaleimide (trade name: BMI-1000, manufactured by Daiwa Chemical Industry Co., Ltd., solid at 25°C, for comparative example) Number average molecular weight: 358.35 (A-6): Aromatic maleimide compound having a biphenylaralkyl skeleton (trade name: MIR-3000, manufactured by Nippon Kayaku Co., Ltd., solid at 25°C, for comparative example) Number average molecular weight: 670

[0091] (B) Epoxy resin (B-1): Bisphenol A liquid epoxy resin (epoxy equivalent: 189 g / eq, product name: jER-828, manufactured by Mitsubishi Chemical Corporation) (B-2): Multifunctional epoxy resin (epoxy equivalent: 166g / eq, product name: EPPN-501H, manufactured by Nippon Kayaku Co., Ltd.)

[0092] (C) Phenolic resin (C-1): a phenolic resin having a triazine ring represented by the following formula (hydroxyl group equivalent: 125 g / eq, product name: LA-7054, manufactured by DIC Corporation) [ka] (C-2): a phenolic resin having a triazine ring represented by the following formula (hydroxyl group equivalent: 151 g / eq, product name: LA-3018-50P, manufactured by DIC Corporation) [ka] (C-3): Phenol novolac resin (product name: TD-2131, manufactured by DIC Corporation, for comparative purposes) (C-4): Cresol novolac resin (product name: KA-1160, manufactured by DIC Corporation, for comparative purposes)

[0093] (D) Curing accelerator (D-1): 2-ethyl-4-methylimidazole (trade name: 2E4MZ, manufactured by Shikoku Kasei Holdings Co., Ltd.) (D-2): Triphenylphosphine (trade name: TPP, manufactured by Hokko Chemical Industry Co., Ltd.) (D-3): Dicumyl peroxide (trade name: Percumyl D, manufactured by NOF Corporation)

[0094] (E) Inorganic filler (E-1): A slurry containing spherical silica particles having an average particle size of 0.5 μm and a solid concentration of 75% by mass, dispersed in toluene (product name: 5SV-CT1, manufactured by Admattex Co., Ltd.)

[0095] Preparation of resin varnish The components shown in Tables 1 to 3, except for component (D), were placed in a 500 mL four-neck flask equipped with a Dimroth condenser and a stirrer, and stirred for 4 hours at 80° C. After cooling to room temperature, component (D) was added and stirred at room temperature for 1 hour, followed by filtration through a 100-mesh wire screen to obtain a varnish-like resin composition.

[0096] <Preparation of uncured resin film> For those resin varnishes that could be produced without any problems using the above procedure, the resin varnish was applied to a 50 μm-thick release-treated PET film (TN-010, manufactured by Toyobo STC) using a roller coater and dried at 100°C for 5 minutes to obtain an uncured resin film with a thickness of 50 μm. However, for Comparative Examples 9 to 14, the uncured resin films were very brittle and difficult to handle.

[0097] <Relative permittivity, dielectric loss tangent> The uncured resin film was fixed directly onto a flat plate together with a release-treated PET film and heated and cured at 180°C for 120 minutes to obtain a cured resin film. A network analyzer (Keysight, product name: E5063-2D5) was connected to a strip line (Keycom Corporation) to measure the relative permittivity and dielectric loss tangent of the cured resin film at a frequency of 10 GHz. The cured resin film was also placed in a constant temperature and humidity chamber at 85°C and 85% humidity for 24 hours, after which the relative permittivity and dielectric loss tangent were similarly measured at a frequency of 10 GHz.

[0098] <Peel strength> A 75mm long, 25mm wide, and 1.0mm thick SUS304 board was prepared. The uncured resin film with the PET film was placed on one surface of the board, with the resin film facing the board. Lamination was performed at 100°C, 0.3 MPa, and 60 seconds. After lamination, the PET film was peeled off, and an 18μm thick copper foil (Ra: 0.17μm, Rz: 0.6μm) was placed on the resin film facing the board. Lamination was performed at 100°C, 0.3 MPa, and 60 seconds. After lamination, the board was heated to 170°C for 30 minutes and cured to prepare adhesive test specimens. To evaluate adhesion, the peel strength (kN / m) of each adhesive test specimen was measured at 23°C and a tensile speed of 50mm / min according to JIS C6481:1996. Furthermore, the cured adhesive test specimens were immersed in a swelling solution (product name: Swelling Dip, manufactured by Atotech Japan) at 60°C for 10 minutes. Next, the test specimens were immersed in a roughening solution (product name: Concentrate Compact P, manufactured by Atotech Japan) at 80°C for 25 minutes. Finally, the test specimens were immersed in a neutralizing solution (product name: Reduction Solution Securigant P, manufactured by Atotech Japan) at 40°C for 5 minutes. After rinsing with water, the peel strength (kN / m) was measured under the same conditions as before the immersion test.

[0099] <Desmear Resistance> A double-sided copper foil glass epoxy substrate (FR-4, product name: R-1075, Panasonic Industries Co., Ltd.) measuring 100 mm in length, 25 mm in width, and 1.0 mm in thickness was prepared and pretreated by reducing the copper in a formic acid reflow oven. The uncured resin film with the PET film was placed on one surface of the substrate, with the resin film facing the substrate, and laminated at 100°C, 0.3 MPa pressure, and 60 seconds. After lamination, the PET film was peeled off and the substrate was cured by heating at 170°C for 30 minutes. Slits were made according to JIS K5600-5-6:1999 (Adhesion (Cross-Cut Method)). The cured substrate was immersed in a swelling solution (product name: Swelling Dip, Atotech Japan) at 60°C for 10 minutes. The cured substrate was then immersed in a roughening solution (product name: Concentrate Compact P, Atotech Japan) at 80°C for 60 minutes. Finally, the substrate with the cured product was immersed in a neutralizing solution (product name: Reduction Solution Securigant P, manufactured by Atotech Japan) at 40°C for 5 minutes. After rinsing with water, it was dried at 120°C for 20 minutes and visually inspected for peeling. Those that showed no peeling were marked with a circle, and those that showed peeling were marked with an ×.

[0100] [Table 1]

[0101] [Table 2]

[0102] [Table 3]

Claims

1. (A) A maleimide compound having one or more hydrocarbon groups derived from a dimer acid skeleton in one molecule (B) Epoxy resin having two or more epoxy groups in one molecule (C) a phenolic resin having a triazine ring, and (D) Curing accelerator wherein the ratio (Ep / Ph) of the number of epoxy groups in the epoxy resin of component (B) to the number of phenolic hydroxyl groups in the phenol resin of component (C) satisfies the following formula (1): [Equation 1]

2. 2. The thermosetting resin composition according to claim 1, wherein the maleimide compound of component (A) is one or more compounds selected from the group consisting of compounds represented by the following formulas (2), (3), and (4), and at least one of the compounds is solid at 25°C: 【Chemistry 1】 (In formula (2), A's are independently tetravalent organic groups having a cyclic structure; B's are independently divalent hydrocarbon groups having 6 to 60 carbon atoms, excluding groups having a dimer acid skeleton; D's are independently groups selected from divalent aliphatic hydrocarbon groups and divalent aromatic hydrocarbon groups having 6 to 60 carbon atoms, at least one of which is a hydrocarbon group derived from a dimer acid skeleton; m1 is 1 to 100; and m2 is 1 to 200. The order of the repeating units bracketed by m1 and m2 is not limited, and the bonding pattern may be alternating, block, or random.) 【Chemistry 2】 (In formula (3), A's are independently tetravalent organic groups having a cyclic structure; D's are independently groups selected from divalent aliphatic hydrocarbon groups and divalent aromatic hydrocarbon groups having 6 to 60 carbon atoms; at least one of the D's is a hydrocarbon group derived from a dimer acid skeleton; and n is 1 to 100.) 【Transformation 3】 (In formula (4), D represents a hydrocarbon group derived from a dimer acid skeleton.)

3. 3. The thermosetting resin composition according to claim 2, wherein A in formulas (2) and (3) is any one of tetravalent organic groups represented by the following structural formulas: 【Chemistry 4】 (The bond not bonded to a substituent in the above structural formula is bonded to the carbonyl carbon that forms the cyclic imide structure in formulas (2) and (3).)

4. 2. The thermosetting resin composition according to claim 1, wherein the phenolic resin (C) having a triazine ring is represented by the following formula (5): 【Transformation 5】 (In formula (5), R is independently a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms, and x is 1 to 30.)

5. 2. The thermosetting resin composition according to claim 1, wherein the curing accelerator (D) is an anionic polymerization initiator.

6. An adhesive film comprising the thermosetting resin composition of claim 1.

7. A prepreg comprising a cured product of the thermosetting resin composition according to claim 1.

8. A resin-coated copper foil comprising a cured product of the thermosetting resin composition according to claim 1.

9. A build-up film comprising the thermosetting resin composition according to claim 1.

10. A laminate comprising the adhesive film according to claim 6.

11. A laminate comprising the prepreg according to claim 7.

12. A laminate comprising the resin-coated copper foil according to claim 8.

13. A laminate comprising the build-up film according to claim 9.

14. A printed wiring board comprising one or more laminates according to any one of claims 10 to 13.

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