Thermosetting resin composition, dielectric substrate, and microstrip antenna

Abstract

To provide a thermosetting resin composition giving a cured product having a high dielectric constant, a low dielectric loss tangent and excellent color (blackness).SOLUTION: The thermosetting resin composition of the present invention includes (A) a thermosetting resin, (B) an inorganic filler containing a high-dielectric filler (B1), and (C) titanium nitride.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a thermosetting resin composition, a dielectric substrate, and a microstrip antenna. [Background technology]

[0002] In recent years, wireless communication has become faster, and there is a demand for higher performance and smaller communication devices. Furthermore, the capacity of wireless communication has increased dramatically in recent years, and the frequencies used for transmission signals have rapidly become wider and higher in frequency. As a result, the frequency bands used by communication devices are no longer compatible with the microwave bands that have been used traditionally, and are now being expanded to include the millimeter wave band. Against this background, there is a strong demand for higher performance in the antennas installed in communication devices.

[0003] Communication devices can be made even more compact by increasing the dielectric constant of the antenna material (dielectric substrate) incorporated inside the device. Furthermore, a smaller dielectric loss tangent of the dielectric substrate results in lower loss, which is advantageous for higher frequencies. Therefore, if a dielectric substrate with a high dielectric constant and a small dielectric loss tangent can be used, it will be possible to increase frequencies, shorten the circuitry, and miniaturize communication devices. Furthermore, since it is necessary to stamp a manufacturing number or the like on the dielectric substrate, which is the product, during the manufacturing process, it is required that the dielectric substrate be black.

[0004] Patent Document 1 discloses a molding resin composition used to seal electronic components in high-frequency devices, which contains an epoxy resin, a curing agent, and an inorganic filler containing predetermined amounts of calcium titanate particles, strontium titanate particles, silica particles, and alumina particles. This document lists carbon black and titanium oxide as examples of colorants, and in the examples, carbon black is used.

[0005] Patent Document 2 discloses an encapsulating resin composition containing an epoxy resin and a curing agent containing an active ester compound, and the carbon black content is 0 mass % to 0.15 mass % relative to the total encapsulating resin composition. This document also lists titanium oxide as an example of a colorant other than carbon black.

[0006] Patent Document 3 discloses titanium oxynitride that is blended into resins such as plastic moldings as a black pigment or a conductivity-imparting agent. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6870778 [Patent Document 2] Patent Publication No. 2021-113253 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-206891 Summary of the Invention [Problem to be solved by the invention]

[0008] However, as described in Patent Documents 1 and 2, when carbon black is used as a colorant, the dielectric loss tangent of the resulting cured product may deteriorate due to electrical conductivity. On the other hand, when titanium oxide is used as a colorant, the deterioration of the dielectric loss tangent is suppressed compared to carbon black, but there is still room for improvement in the color (blackness) of the cured product. Furthermore, Patent Document 3 does not disclose titanium nitride. [Means for solving the problem]

[0009] The present inventors have conducted research in light of these problems and have discovered that the use of titanium nitride as a colorant improves both the low dielectric tangent and color of the resulting cured product, thereby completing the present invention. That is, the present invention can be shown as follows.

[0010] [1] (A) a thermosetting resin; (B) an inorganic filler containing a high dielectric filler (B1); (C) titanium nitride; A thermosetting resin composition comprising: [2] The thermosetting resin composition according to [1], wherein the highly dielectric filler (B1) comprises at least one selected from calcium titanate, strontium titanate, magnesium titanate, magnesium zirconate, strontium zirconate, bismuth titanate, zirconium titanate, zinc titanate, barium zirconate, calcium titanate zirconate, lead titanate zirconate, barium magnesium niobate, and calcium zirconate. [3] The thermosetting resin composition according to [1], wherein the high dielectric filler (B1) contains calcium titanate. [4] The thermosetting resin composition according to any one of [1] to [3], further comprising titanium oxide (D). [5] The thermosetting resin composition according to [4], wherein the total amount of the titanium nitride (C) and the titanium oxide (D) is 0.1% by mass or more and 8% by mass or less, based on 100% by mass of the entire resin composition. [6] In a total of 100 mass% of titanium nitride (C) and titanium oxide (D), Titanium nitride (C) is 35% by weight or more and 75% by mass or less, and The thermosetting resin composition according to [4], comprising titanium oxide (D) in an amount of 25% by weight or more and 65% by mass or less. [7] The thermosetting resin composition according to any one of [1] to [6], wherein the titanium nitride (C) has an average particle size of 0.01 μm to 5 μm. [8] The thermosetting resin composition according to any one of [1] to [7], wherein the high dielectric filler (B1) is contained in an amount of 20% by volume or more and 95% by volume or more relative to 100% by volume of the inorganic filler (B). [9] The thermosetting resin composition according to any one of [1] to [8], further comprising a curing agent (E).

[10] The curing agent (E) comprises an active ester curing agent (E1), The thermosetting resin composition according to [9], wherein the active ester curing agent (E1) includes at least one selected from the group consisting of an active ester curing agent containing a dicyclopentadiene-type diphenol structure, an active ester curing agent containing a naphthalene structure, an active ester curing agent containing an acetylated product of phenol novolac, and an active ester curing agent containing a benzoylated product of phenol novolac.

[11] The thermosetting resin composition according to

[10] , wherein the active ester curing agent (E1) has a structure represented by the following general formula (1): [ka] In general formula (1), A is a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group, Ar′ is a substituted or unsubstituted aryl group, B is a structure represented by the following general formula (B): [ka] (In general formula (B), Ar represents a substituted or unsubstituted arylene group; Y represents a single bond, a substituted or unsubstituted linear alkylene group having 1 to 6 carbon atoms, or a substituted or unsubstituted cyclic alkylene group having 3 to 6 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group, an ether bond, a carbonyl group, a carbonyloxy group, a sulfide group, or a sulfone group; and n represents an integer of 0 to 4.) k is the average value of the repeating units and is in the range of 0.25 to 3.5.

[12] The thermosetting resin composition according to any one of [1] to

[11] , further comprising a curing catalyst (F).

[13] L of the cured product of the thermosetting resin composition * a * b * In color coordinates, Lightness L * The value of is 24 to 47, a * The value is -3.0 to 0.0, b * The thermosetting resin composition according to any one of [1] to

[12] , wherein the value of is −6.0 to −1.5.

[14] The thermosetting resin composition according to any one of [1] to

[13] , which is used as a material for forming a microstrip antenna.

[15] The thermosetting resin composition according to any one of [1] to

[13] , which is used as a material for forming a dielectric waveguide.

[16] The thermosetting resin composition according to any one of [1] to

[13] , which is used as a material for forming an electromagnetic wave absorber.

[17] A dielectric substrate comprising a cured product of the thermosetting resin composition according to any one of [1] to

[13] .

[18] A dielectric substrate according to

[17] , a radiation conductor plate provided on one surface of the dielectric substrate; a ground conductor plate provided on the other surface of the dielectric substrate; A microstrip antenna comprising:

[19] Dielectric substrate, a radiation conductor plate provided on one surface of the dielectric substrate; a ground conductor plate provided on the other surface of the dielectric substrate; a high dielectric material disposed opposite the radiation conductor plate; A microstrip antenna comprising: A microstrip antenna in which the high dielectric is composed of the dielectric substrate described in

[17] . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a thermosetting resin composition that can give a cured product having a high dielectric constant, a low dielectric loss tangent, and an excellent color (blackness). In other words, the cured product obtained from the thermosetting resin composition of the present invention has an excellent balance of a high dielectric constant, a low dielectric loss tangent, and an excellent color (blackness). [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a top perspective view showing a microstrip antenna according to an embodiment of the present invention. [Figure 2]FIG. 10 is a cross-sectional view showing another aspect of the microstrip antenna of the present embodiment. [Figure 3] 1 is a photograph showing the color (blackness) of cured products obtained from the thermosetting resin compositions of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are denoted by similar reference numerals, and their description will be omitted where appropriate. For example, "1 to 10" represents "1 or more" to "10 or less" unless otherwise specified.

[0014] The thermosetting resin composition of the present embodiment contains (A) a thermosetting resin, (B) an inorganic filler containing a high dielectric filler (B1), and (C) titanium nitride. Such a thermosetting resin composition can give a cured product having a high dielectric constant, a low dielectric loss tangent, and an excellent color (blackness). In other words, the cured product obtained from the thermosetting resin composition of the present invention has an excellent balance of a high dielectric constant, a low dielectric loss tangent, and a color.

[0015] [Thermosetting resin (A)] In this embodiment, the thermosetting resin (A) may be one or more selected from the group consisting of cyanate resins, epoxy resins, resins having two or more radically polymerizable carbon-carbon double bonds in one molecule, and maleimide resins. Among these, from the viewpoint of achieving the effects of the present invention and improving the adhesiveness of the thermally conductive paste, it is particularly preferable to include an epoxy resin (A1).

[0016] The epoxy resin (A1) can be any monomer, oligomer or polymer having two or more epoxy groups in one molecule, and there are no limitations on the molecular weight or molecular structure.

[0017] Examples of the epoxy resin (A1) include biphenyl-type epoxy resins; bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and tetramethylbisphenol F-type epoxy resins; stilbene-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolac-type epoxy resins; polyfunctional epoxy resins such as trisphenol-type epoxy resins exemplified by triphenolmethane-type epoxy resins and alkyl-modified triphenolmethane-type epoxy resins; phenol aralkyl-type epoxy resins having a phenylene skeleton, and naphthol aralkyl-type epoxy resins having a phenylene skeleton. the epoxy resins include one or more selected from the group consisting of phenol aralkyl type epoxy resins such as phenol aralkyl type epoxy resins having a biphenylene skeleton, and naphthol aralkyl type epoxy resins having a biphenylene skeleton; naphthol type epoxy resins such as dihydroxynaphthalene type epoxy resins and epoxy resins obtained by glycidyl etherifying a dihydroxynaphthalene dimer; triazine nucleus-containing epoxy resins such as triglycidyl isocyanurate and monoallyl diglycidyl isocyanurate; and bridged cyclic hydrocarbon compound-modified phenol type epoxy resins such as dicyclopentadiene-modified phenol type epoxy resins.

[0018] Of these, novolac epoxy resins, polyfunctional epoxy resins, and phenol aralkyl epoxy resins are preferably used from the viewpoint of the effects of the present invention. Also, from the same viewpoint, the epoxy resin preferably contains one or more selected from the group consisting of orthocresol novolac epoxy resins, phenol aralkyl epoxy resins having a biphenylene skeleton, and triphenylmethane epoxy resins, and more preferably contains one or more selected from the group consisting of orthocresol novolac epoxy resins and phenol aralkyl epoxy resins having a biphenylene skeleton.

[0019] From the viewpoint of the effects of the present invention, the epoxy resin (A1) may be contained in an amount of preferably 2% by mass or more and 25% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and even more preferably 5% by mass or more and 15% by mass or less, based on the entire thermosetting resin composition.

[0020] [Inorganic filler (B)] The inorganic filler (B) contains a high dielectric filler (B1). Furthermore, the inorganic filler (B) may contain an inorganic filler (B2) other than the high dielectric filler (B1).

[0021] (High dielectric filler (B1)) As the high dielectric filler (B1), known high dielectric fillers can be used as long as the effects of the present invention are achieved, and examples thereof include calcium titanate, strontium titanate, magnesium titanate, magnesium zirconate, strontium zirconate, bismuth titanate, zirconium titanate, zinc titanate, barium zirconate, calcium titanate zirconate, lead titanate zirconate, barium magnesium niobate, and calcium zirconate, and the filler can contain one or a combination of two or more selected from these.

[0022] From the viewpoint of the effects of the present invention, the high dielectric filler (B1) is preferably at least one selected from calcium titanate, strontium titanate, and magnesium titanate, more preferably contains calcium titanate or magnesium titanate, and even more preferably contains calcium titanate.

[0023] The shape of the high dielectric filler (B1) may be granular, amorphous, flake-like, etc., and high dielectric fillers of these shapes can be used in any ratio. From the viewpoints of the effects of the present invention and flowability and filling properties, the average particle size of the high dielectric filler (B1) is preferably 0.1 μm or more and 50 μm or less, more preferably 0.3 μm or more and 20 μm or less, and even more preferably 0.5 μm or more and 10 μm or less. The average particle size is the volume average particle size (e.g., D50 ) and can be measured using a laser diffraction particle size distribution analyzer.

[0024] From the viewpoint of the effects of the present invention, the high dielectric filler (B1) can be contained in an amount of preferably 20% by volume or more and 95% by volume or less, more preferably 25% by volume or more and 90% by volume or less, and even more preferably 30% by volume or more and 85% by volume or less, relative to 100% by volume of the inorganic filler (B).

[0025] The amount of the highly dielectric filler (B1) to be blended is preferably 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more, based on 100% by mass of the thermosetting resin composition, with the upper limit being 80% by mass or less. When the amount of the high dielectric filler (B1) added is within the above range, the resulting cured product has an excellent high dielectric constant and low dielectric loss tangent, and is also excellent in the production of molded articles.

[0026] (Other inorganic fillers (B2)) Examples of inorganic fillers (B2) other than the high dielectric filler (B1) include powders such as fused silica, crystalline silica, alumina, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, etc., as well as beads obtained by spheronizing these, glass fiber, etc. These inorganic fillers may be used alone or in combination of two or more.

[0027] From the viewpoint of the effects of the present invention and fluidity and packing properties, the average particle size of the inorganic filler (B2) is preferably 0.1 μm or more and 60 μm or less, more preferably 0.3 μm or more and 50 μm or less, and even more preferably 0.5 μm or more and 40 μm or less. The average particle size is the volume average particle size (e.g., D 50 ) and can be measured using a laser diffraction particle size distribution analyzer.

[0028] From the viewpoints of moldability, reduction of thermal expansion, and improvement of strength, the blending amount of the inorganic filler (B2) can be preferably in the range of 3 to 50% by mass, more preferably 5 to 40% by mass, and even more preferably 8 to 35% by mass, based on the entire thermosetting resin composition. Within the above range, excellent reduction of thermal expansion and moldability are achieved.

[0029] [Titanium nitride (C)] The titanium nitride (C) contained in the thermosetting resin composition of the present embodiment is TiN x (where X is greater than or equal to 1 and less than 2).

[0030] The average particle size of titanium nitride (C) is preferably 0.01 μm or more and 5 μm or less, more preferably 0.02 μm or more and 3 μm or less, and even more preferably 0.05 μm or more and 1 μm or less. The average particle size is determined by the volume average particle size (for example, D 50 ) and can be measured using a laser diffraction particle size distribution analyzer. When the average particle size of the titanium nitride (C) is within the above range, a cured product having excellent moldability, high dielectric constant, low dielectric loss tangent, and excellent color (blackness) can be obtained.

[0031] From the viewpoint of the effects of the present invention, the titanium nitride (C) content can be preferably in the range of 0.03 mass % or more and 7 mass % or less, more preferably 0.06 mass % or more and 6 mass % or less, and even more preferably 0.15 mass % or more and 4 mass % or less, relative to 100 mass % of the entire resin composition.

[0032] [Titanium dioxide (D)] The thermosetting resin composition of the present embodiment may further contain titanium oxide (D). Titanium oxide (D) is TiO x (wherein X is 1 or more and less than 2) In this embodiment, by using titanium nitride (C) and titanium oxide (D) in combination, a cured product having a high dielectric constant, a low dielectric loss tangent, and an even more excellent color (blackness) can be obtained.

[0033] The average particle size of titanium oxide (D) is preferably 0.1 μm or more and 8 μm or less, more preferably 0.2 μm or more and 3 μm or less, and even more preferably 0.3 μm or more and 2 μm or less. The average particle size is determined by the volume average particle size (for example, D 50 ) and can be measured using a laser diffraction particle size distribution analyzer.

[0034] From the viewpoint of the effects of the present invention, the content of titanium oxide (D) can be preferably in the range of 0.02 mass % or more and 6 mass % or less, more preferably 0.04 mass % or more and 5 mass % or less, and even more preferably 0.1 mass % or more and 3.5 mass % or less, relative to 100 mass % of the entire resin composition.

[0035] When the thermosetting resin composition of the present embodiment contains titanium oxide (D), the total amount of titanium nitride (C) and titanium oxide (D) can be set to preferably from 0.1% by mass to 8% by mass, more preferably from 0.2% by mass to 7% by mass, and even more preferably from 0.5% by mass to 5% by mass, relative to 100% by mass of the entire resin composition. This makes it possible to obtain a cured product that has a low dielectric loss tangent, a high dielectric constant, and excellent color, and has an excellent balance of these properties.

[0036] Furthermore, when the thermosetting resin composition of the present embodiment contains titanium oxide (D), the total amount of the titanium nitride (C) and the titanium oxide (D) is 100 mass %, and The titanium nitride (C) content is preferably 35% by weight or more and 75% by mass or less, more preferably 40% by mass or more and 70% by mass or less, and even more preferably 45% by mass or more and 65% by mass or less, The titanium oxide (D) is contained in an amount of preferably 25% by weight or more and 65% by mass or less, more preferably 30% by mass or more and 60% by mass or less, and even more preferably 35% by mass or more and 55% by mass or less. This makes it possible to obtain a cured product that has a low dielectric loss tangent, a high dielectric constant, and excellent color, and has an excellent balance of these properties.

[0037] In this embodiment, titanium nitride (C) and titanium oxide (D) can be used as colorants, and the thermosetting resin composition can further contain other colorants.

[0038] Examples of other colorants include known colorants such as carbon black, organic dyes, organic pigments, red lead, and red iron oxide. The content of other colorants can be appropriately selected depending on the purpose.

[0039] [Hardening agent (E)] The thermosetting resin composition of this embodiment may further contain a curing agent (E). As the curing agent (E), any known curing agent can be used as long as the effects of the present invention are achieved, but examples thereof include active ester curing agents and phenolic curing agents, and it is preferable to use an active ester curing agent (E1).

[0040] The active ester curing agent (E1) may be a compound having one or more active ester groups in one molecule. Among them, the active ester curing agent (E1) is preferably a compound having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds.

[0041] Preferred examples of the active ester curing agent (E1) include active ester curing agents containing a dicyclopentadiene-type diphenol structure, active ester curing agents containing a naphthalene structure, active ester curing agents containing an acetylated product of phenol novolac, and active ester curing agents containing a benzoylated product of phenol novolac, and at least one of these may be included. Among these, active ester curing agents containing a naphthalene structure and active ester curing agents containing a dicyclopentadiene-type diphenol structure are more preferred. The "dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene. In this embodiment, the active ester curing agent (E1) may be, for example, a resin having a structure represented by the following general formula (1).

[0042] [ka]

[0043] In general formula (1), "B" is a structure represented by general formula (B).

[0044] [ka]

[0045] In general formula (B), Ar is a substituted or unsubstituted arylene group. Examples of the substituent of the substituted arylene group include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, and an aralkyl group.

[0046] Y is a single bond, a substituted or unsubstituted linear alkylene group having 1 to 6 carbon atoms, a substituted or unsubstituted cyclic alkylene group having 3 to 6 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group, an ether bond, a carbonyl group, a carbonyloxy group, a sulfide group, or a sulfone group. Substituents for the above groups include alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, phenyl groups, and aralkyl groups.

[0047] Preferred examples of Y include a single bond, a methylene group, -CH(CH3)2-, an ether bond, an optionally substituted cycloalkylene group, and an optionally substituted 9,9-fluorenylene group. n is an integer of 0 to 4, and is preferably 0 or 1.

[0048] Specifically, B is a structure represented by the following general formula (B1) or (B2).

[0049] [ka]

[0050] In the general formula (B1) and the general formula (B2), Ar and Y have the same meanings as in the general formula (B). A is a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group; Ar' is a substituted or unsubstituted aryl group; k is the average value of the repeating units and is in the range of 0.25 to 3.5.

[0051] The thermosetting resin composition of the present embodiment contains a specific active ester curing agent, and the resulting cured product can have excellent dielectric properties and an excellent low dielectric loss tangent.

[0052] The active ester curing agent (E1) used in the thermosetting resin composition of this embodiment has an active ester group represented by formula (B). In the curing reaction between the epoxy resin and the active ester curing agent (E1), the active ester group of the active ester curing agent (E1) reacts with the epoxy group of the epoxy resin to generate a secondary hydroxyl group. This secondary hydroxyl group is blocked by the ester residue of the active ester curing agent (E1). This reduces the dielectric tangent of the cured product. In one embodiment, the structure represented by the above formula (B) is preferably at least one selected from the following formulae (B-1) to (B-6).

[0053] [ka]

[0054] In formulas (B-1) to (B-6), R 1 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group,

[0055] R 2are each independently any one of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a phenyl group, and X is any one of a linear alkylene group having 2 to 6 carbon atoms, an ether bond, a carbonyl group, a carbonyloxy group, a sulfide group, and a sulfone group, n is an integer of 0 to 4, and p is an integer of 1 to 4.

[0056] The structures represented by the above formulas (B-1) to (B-6) are all highly oriented structures. Therefore, when an active ester curing agent containing such a structure is used, the resulting cured product of the thermosetting resin composition has a low dielectric tangent and excellent adhesion to metals, and is therefore suitable for use as an antenna material.

[0057] Among them, from the viewpoint of low dielectric loss tangent, active ester curing agents having a structure represented by formula (B-2), formula (B-3) or formula (B-5) are preferred, and more preferred are active ester curing agents having a structure in which n is 0 in formula (B-2), a structure in which X is an ether bond in formula (B-3), or a structure in formula (B-5) in which two carbonyloxy groups are at the 4,4'-positions. 1 are preferably all hydrogen atoms.

[0058] In formula (1), "Ar'" is an aryl group, such as a phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 3,5-xylyl group, o-biphenyl group, m-biphenyl group, p-biphenyl group, 2-benzylphenyl group, 4-benzylphenyl group, 4-(α-cumyl)phenyl group, 1-naphthyl group, 2-naphthyl group, etc. Among these, a 1-naphthyl group or a 2-naphthyl group is preferred, as this gives a cured product with a particularly low dielectric dissipation factor.

[0059] In this embodiment, "A" in the active ester curing agent represented by formula (1) is a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group. Examples of such arylene groups include a structure obtained by a polyaddition reaction between an unsaturated aliphatic cyclic hydrocarbon compound containing two double bonds in one molecule and a phenolic compound.

[0060] Examples of the unsaturated aliphatic cyclic hydrocarbon compound containing two double bonds per molecule include dicyclopentadiene, cyclopentadiene polymers, tetrahydroindene, 4-vinylcyclohexene, 5-vinyl-2-norbornene, and limonene. These may be used alone or in combination of two or more. Among these, dicyclopentadiene is preferred because it can produce cured products with excellent heat resistance. Since dicyclopentadiene is contained in petroleum fractions, industrial dicyclopentadiene may contain cyclopentadiene polymers and other aliphatic or aromatic diene compounds as impurities. However, considering performance such as heat resistance, curability, and moldability, it is desirable to use a dicyclopentadiene product with a purity of 90% by mass or higher.

[0061] On the other hand, examples of the phenolic compound include phenol, cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorophenol, bromophenol, 1-naphthol, 2-naphthol, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, etc., and these may be used alone or in combination of two or more. Among these, phenol is preferred because it serves as an active ester curing agent with high curability and excellent dielectric properties in the cured product.

[0062] In a preferred embodiment, "A" in the active ester curing agent represented by formula (1) has a structure represented by formula (A): A thermosetting resin composition containing an active ester curing agent in which "A" in formula (1) has the following structure produces a cured product with a low dielectric tangent and excellent adhesion to insert articles.

[0063] [ka]

[0064] In formula (A), R 3 each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group, l is 0 or 1, and m is an integer of 1 or more.

[0065] Among the active ester curing agents represented by formula (1), more preferred are resins represented by the following formulas (1-1), (1-2) and (1-3), and particularly preferred is resin represented by the following formula (1-3).

[0066] [ka]

[0067] In formula (1-1), R 1 and R 3 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group; Z is a phenyl group, a naphthyl group, or a phenyl group or naphthyl group having 1 to 3 alkyl groups having 1 to 4 carbon atoms on the aromatic nucleus; l is 0 or 1; and k is the average of the repeating units and is 0.25 to 3.5.

[0068] [ka]

[0069] In formula (1-2), R 1 and R 3 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group; Z is a phenyl group, a naphthyl group, or a phenyl group or naphthyl group having 1 to 3 alkyl groups having 1 to 4 carbon atoms on the aromatic nucleus; l is 0 or 1; and k is the average of the repeating units and is 0.25 to 3.5.

[0070] [ka]

[0071] In formula (1-3), R 1 and R 3 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, or an aralkyl group; Z is a phenyl group, a naphthyl group, or a phenyl group or naphthyl group having 1 to 3 alkyl groups having 1 to 4 carbon atoms on the aromatic nucleus; l is 0 or 1; and k is the average of the repeating units and is 0.25 to 3.5.

[0072] The active ester curing agent (E1) used in the present invention can be produced by a known method in which a phenolic compound (a) having a structure in which a plurality of aryl groups each having a phenolic hydroxyl group are linked via an aliphatic cyclic hydrocarbon group, an aromatic nucleus-containing dicarboxylic acid or a halide thereof (b), and an aromatic monohydroxy compound (c) are reacted.

[0073] The reaction ratios of the phenolic compound (a), aromatic nucleus-containing dicarboxylic acid or its halide (b), and aromatic monohydroxy compound (c) can be appropriately adjusted depending on the desired molecular design. Among these, since an active ester curing agent with higher curing properties can be obtained, it is preferable to use the respective raw materials in a ratio such that the phenolic hydroxyl groups of the phenolic compound (a) are in the range of 0.25 to 0.90 moles and the hydroxyl groups of the aromatic monohydroxy compound (c) are in the range of 0.10 to 0.75 moles per mole of the total of carboxyl groups or acid halide groups of the aromatic nucleus-containing dicarboxylic acid or its halide (b), and it is more preferable to use the respective raw materials in a ratio such that the phenolic hydroxyl groups of the phenolic compound (a) are in the range of 0.50 to 0.75 moles and the hydroxyl groups of the aromatic monohydroxy compound (c) are in the range of 0.25 to 0.50 moles.

[0074] Furthermore, when the total number of functional groups of the resin is defined as the sum of the arylcarbonyloxy groups and phenolic hydroxyl groups in the resin structure, the functional group equivalent of the active ester curing agent (E1) is preferably in the range of 200 g / eq or more and 230 g / eq or less, and more preferably in the range of 210 g / eq or more and 220 g / eq or less, in order to obtain a cured product with excellent curability and low dielectric constant and dielectric dissipation factor.

[0075] In the thermosetting resin composition of this embodiment, the active ester curing agent (E1) and the epoxy resin (A1) are preferably blended in such a ratio that the epoxy groups in the epoxy resin (A1) are 0.8 to 1.2 equivalents per equivalent of the total active groups in the active ester curing agent (E1), since this provides a cured product with excellent curing properties and a low dielectric loss tangent. Here, the active groups in the active ester curing agent (E1) refer to arylcarbonyloxy groups and phenolic hydroxyl groups in the resin structure.

[0076] Furthermore, a phenol-based curing agent can also be used as the curing agent (E). Examples of phenol-based curing agents include polyhydric phenol compounds such as phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadiene phenol adduct resin, phenol aralkyl resin, naphthol aralkyl resin, trimethylolmethane resin, tetraphenylolethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, biphenyl-modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked via bismethylene groups), biphenyl-modified naphthol resin (a polyhydric naphthol compound in which phenol nuclei are linked via bismethylene groups), and aminotriazine-modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked via melamine, benzoguanamine, or the like).

[0077] The amount of the curing agent (E) to be blended is preferably 50% by mass or more and 90% by mass or less, based on 100% by mass of the epoxy resin (A1). By using the curing agent in the amount within the above range, a resin composition having excellent curability can be obtained.

[0078] The curing agent (E) is used in an amount of preferably 0.2% by mass or more and 15% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, and even more preferably 1% by mass or more and 8% by mass or less, based on the total amount of the thermosetting resin composition. By including the curing agent (B) in the above range, the resulting cured product can have better dielectric properties and an even lower dielectric loss tangent.

[0079] [Curing catalyst (F)] The thermosetting resin composition of the present embodiment may further contain a curing catalyst (F). The curing catalyst (F) may also be called a curing accelerator, etc. The curing catalyst (F) is not particularly limited as long as it accelerates the curing reaction of the thermosetting resin, and known curing catalysts can be used.

[0080] Specific examples of the curing catalyst (F) include phosphorus atom-containing compounds such as organic phosphines, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds; imidazoles (imidazole curing accelerators) such as 2-methylimidazole and 2-phenylimidazole; and nitrogen atom-containing compounds such as amidines and tertiary amines, exemplified by 1,8-diazabicyclo[5.4.0]undecene-7 and benzyldimethylamine, and quaternary salts of amidines and amines, and these may be used alone or in combination of two or more.

[0081] Among these, from the viewpoint of improving curability and obtaining a magnetic material excellent in mechanical strength such as bending strength, it is preferable to contain a phosphorus atom-containing compound, more preferably to contain a compound having latent properties such as a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, or an adduct of a phosphonium compound and a silane compound, and particularly preferably a tetra-substituted phosphonium compound, an adduct of a phosphine compound and a quinone compound, or an adduct of a phosphonium compound and a silane compound. By using a latent curing catalyst, it is possible to obtain a magnetic material that is superior in moldability and mechanical strength such as bending strength.

[0082] Examples of organic phosphines include primary phosphines such as ethylphosphine and phenylphosphine; secondary phosphines such as dimethylphosphine and diphenylphosphine; and tertiary phosphines such as trimethylphosphine, triethylphosphine, tributylphosphine and triphenylphosphine.

[0083] Examples of the tetra-substituted phosphonium compound include compounds represented by the following general formula (6).

[0084] [ka]

[0085] In general formula (6), P represents a phosphorus atom. R 4 , R 5 , R 6 and R 7 each independently represents an aromatic group or an alkyl group. A represents the anion of an aromatic organic acid having at least one functional group selected from a hydroxyl group, a carboxyl group, and a thiol group on the aromatic ring. AH represents an aromatic organic acid having at least one functional group selected from a hydroxyl group, a carboxyl group, and a thiol group on an aromatic ring. x and y are 1 to 3, z is 0 to 3, and x=y.

[0086] The compound represented by the general formula (6) can be obtained, for example, as follows. First, a tetra-substituted phosphonium halide, an aromatic organic acid, and a base are mixed uniformly in an organic solvent, generating an anion of the aromatic organic acid in the solution. Then, water is added to precipitate the compound represented by general formula (6). In the compound represented by general formula (6), the R bonded to the phosphorus atom 4 , R 5 , R 6 and R 7 is preferably a phenyl group, AH is a compound having a hydroxyl group on an aromatic ring, i.e., a phenol, and A is an anion of the phenol. Examples of the phenol include monocyclic phenols such as phenol, cresol, resorcinol, and catechol, condensed polycyclic phenols such as naphthol, dihydroxynaphthalene, and anthraquinol, bisphenols such as bisphenol A, bisphenol F, and bisphenol S, and polycyclic phenols such as phenylphenol and biphenol.

[0087] Examples of phosphobetaine compounds include compounds represented by the following general formula (7).

[0088] [ka]

[0089] In general formula (7), P represents a phosphorus atom. R 8 is an alkyl group having 1 to 3 carbon atoms, R 9 represents a hydroxyl group. f is a number between 0 and 5, and g is a number between 0 and 3.

[0090] The compound represented by the general formula (7) can be obtained, for example, as follows. First, a triaromatic-substituted phosphine, which is a tertiary phosphine, is brought into contact with a diazonium salt to substitute the diazonium group of the diazonium salt with the triaromatic-substituted phosphine.

[0091] Examples of the adduct of a phosphine compound and a quinone compound include compounds represented by the following general formula (8).

[0092] [ka]

[0093] In general formula (8), P represents a phosphorus atom. R 10 , R 11 and R 12 represents an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may be the same or different. R 13 , R 14 and R 15 represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and may be the same or different; R 14 and R 15 may be bonded to form a cyclic structure.

[0094] The phosphine compound used in the adduct of a phosphine compound and a quinone compound is preferably, for example, triphenylphosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, trinaphthylphosphine, tris(benzyl)phosphine, etc., which is unsubstituted or has a substituent such as an alkyl group or alkoxy group on the aromatic ring, and examples of the substituent such as an alkyl group or alkoxy group include those having a carbon number of 1 to 6. From the viewpoint of availability, triphenylphosphine is preferred.

[0095] The quinone compound used in the adduct of a phosphine compound and a quinone compound includes benzoquinone and anthraquinones, and among these, p-benzoquinone is preferred from the viewpoint of storage stability.

[0096] The adduct of a phosphine compound and a quinone compound can be produced by contacting and mixing the organic tertiary phosphine and the benzoquinone in a solvent that can dissolve both of them. The solvent is preferably a ketone such as acetone or methyl ethyl ketone, which has low solubility in the adduct, but is not limited thereto.

[0097] In the compound represented by general formula (8), R bonded to the phosphorus atom 10 , R 11 and R 12 is a phenyl group, and R 13 , R 14 and R 15 is a hydrogen atom, that is, a compound obtained by adding 1,4-benzoquinone and triphenylphosphine, is preferred in that it reduces the modulus of elasticity of the cured product of the encapsulating resin composition when heated.

[0098] Examples of the adduct of a phosphonium compound and a silane compound include compounds represented by the following general formula (9).

[0099] [ka]

[0100] In general formula (9), P represents a phosphorus atom, and Si represents a silicon atom.

[0101] R 16 , R 17 , R 18 and R 19 each represents an organic group having an aromatic ring or a heterocyclic ring, or an aliphatic group, and may be the same or different. R 20 is the group Y 2 and Y 3 It is an organic group that bonds to R 21 is the group Y 4 and Y 5 It is an organic group that bonds to

[0102] Y 2 and Y 3 represents a group formed by releasing a proton from a proton-donating group, and a group Y 2 and Y 3 is bonded to a silicon atom to form a chelate structure.

[0103] Y 4 and Y 5 represents a group formed by releasing a proton from a proton-donating group, and a group Y 4 and Y 5 is bonded to a silicon atom to form a chelate structure. R 20 , and R 21 may be the same or different, and Y 2 , Y 3 , Y 4 and Y 5 may be the same or different from each other. Z1 is an organic group having an aromatic ring or a heterocyclic ring, or an aliphatic group.

[0104] In general formula (9), R 16 , R 17 , R 18 and R 19Examples of the alkyl group include a phenyl group, a methylphenyl group, a methoxyphenyl group, a hydroxyphenyl group, a naphthyl group, a hydroxynaphthyl group, a benzyl group, a methyl group, an ethyl group, an n-butyl group, an n-octyl group, and a cyclohexyl group. Among these, an aromatic group having a substituent such as an alkyl group, an alkoxy group, or a hydroxyl group, such as a phenyl group, a methylphenyl group, a methoxyphenyl group, a hydroxyphenyl group, or a hydroxynaphthyl group, or an unsubstituted aromatic group is more preferred.

[0105] In general formula (9), R 20 is Y 2 and Y 3 Similarly, R 21 is the group Y 4 and Y 5 Y is an organic group that bonds to 2 and Y 3 is a group formed by releasing a proton from a proton-donating group, and a group Y 2 and Y 3 is bonded to a silicon atom to form a chelate structure. 4 and Y 5 is a group formed by releasing a proton from a proton-donating group, and a group Y 4 and Y 5 is bonded to the silicon atom to form a chelate structure. 20 and R 21 may be the same or different, and the group Y 2 , Y 3 , Y 4 and Y5 may be the same or different from each other. 2 -R 20 -Y 3 - and Y 4 -R 21 -Y 5The group represented by - is composed of a group formed by a proton donor releasing two protons, and as the proton donor, an organic acid having at least two carboxyl groups or hydroxyl groups in the molecule is preferred, and an aromatic compound having at least two carboxyl groups or hydroxyl groups on adjacent carbons constituting an aromatic ring is more preferred, and an aromatic compound having at least two hydroxyl groups on adjacent carbons constituting an aromatic ring is more preferred, and examples thereof include catechol, pyrogallol, 1,2-dihydro- Examples of the dihydroxynaphthalene include xynaphthalene, 2,3-dihydroxynaphthalene, 2,2'-biphenol, 1,1'-bi-2-naphthol, salicylic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, chloranilic acid, tannic acid, 2-hydroxybenzyl alcohol, 1,2-cyclohexanediol, 1,2-propanediol, and glycerin. Of these, catechol, 1,2-dihydroxynaphthalene, and 2,3-dihydroxynaphthalene are more preferred.

[0106] Z in general formula (9) 1 represents an organic group or an aliphatic group having an aromatic ring or a heterocyclic ring, and specific examples thereof include aliphatic hydrocarbon groups such as methyl, ethyl, propyl, butyl, hexyl, and octyl groups; aromatic hydrocarbon groups such as phenyl, benzyl, naphthyl, and biphenyl groups; glycidyloxy groups such as glycidyloxypropyl, mercaptopropyl, and aminopropyl groups; mercapto groups; alkyl groups having amino groups; and reactive substituents such as vinyl groups. Among these, methyl, ethyl, phenyl, naphthyl, and biphenyl groups are more preferred in terms of thermal stability. The method for producing the adduct of a phosphonium compound and a silane compound is, for example, as follows.

[0107] A silane compound such as phenyltrimethoxysilane and a proton donor such as 2,3-dihydroxynaphthalene are dissolved in a flask containing methanol, and then a sodium methoxide-methanol solution is added dropwise at room temperature with stirring. A previously prepared solution of a tetra-substituted phosphonium halide such as tetraphenylphosphonium bromide dissolved in methanol is then added dropwise at room temperature with stirring, resulting in the precipitation of crystals. The precipitated crystals are filtered, washed with water, and vacuum dried to obtain an adduct of the phosphonium compound and the silane compound.

[0108] When a curing catalyst is used, its content is preferably 0.1 to 3 mass %, more preferably 0.2 to 2 mass %, based on the total mass of the thermosetting resin composition. By setting the content within this range, a sufficient curing-accelerating effect can be obtained without excessively impairing other performances.

[0109] [Other ingredients] In addition to the above components, the thermosetting resin composition of the present embodiment may contain various components such as a silane coupling agent, a release agent, a dispersant, and a stress reducing agent, as needed.

[0110] <Thermosetting resin composition> The thermosetting resin composition of this embodiment can be produced by uniformly mixing the above-mentioned components.

[0111] Examples of the production method include a method in which predetermined amounts of raw materials are thoroughly mixed using a mixer or the like, then melt-kneaded using a mixing roll, kneader, extruder, etc., and then cooled and pulverized. The obtained thermosetting resin composition may be tableted, if necessary, to dimensions and mass suitable for molding conditions.

[0112] <Cured product> The cured product obtained from the thermosetting resin composition of the present embodiment has a high dielectric constant and a low dielectric loss tangent in the high frequency band, which allows for higher frequencies, thereby shortening circuits, and miniaturizing communication devices, etc., and can be suitably used as a material for forming a microstrip antenna, a material for forming a dielectric waveguide, and a material for forming an electromagnetic wave absorber, etc.

[0113] Furthermore, the cured product of the thermosetting resin composition (molding temperature 175°C, curing time 100 seconds, molding pressure 8 MPa) preferably has L * a * b * In color coordinates, lightness L * is 24 to 47, preferably 25 to 42, and a * is -3.0 to 0.0, preferably -3.0 to -1.0, and b * The value of is -6.0 to -1.5, preferably -5.0 to -2.0. L of the cured product * , a * and b * When the value is in the above range, the color (blackness) is excellent, resulting in excellent printability, and the dielectric properties can also be reduced. L * , a * and b * The value of can be controlled by a known method, for example, by selecting the type of colorant or adjusting the content.

[0114] where L * , a * and b * The value of L is based on the 1976 definition of the International Commission on Illumination (CIE). * , a * and b * can be measured using a commercially available colorimeter. The high-frequency device of this embodiment includes a cured product obtained from a thermosetting resin composition. An example of a high frequency device will be described below.

[0115] <Microstrip antenna> As shown in Figure 1, the microstrip antenna 10 comprises a dielectric substrate 12 formed by curing the above-mentioned thermosetting resin composition, a radiating conductor plate (radiating element) 14 provided on one surface of the dielectric substrate 12, and a ground conductor plate 16 provided on the other surface of the dielectric substrate 12. The radiation conductor plate may be rectangular or circular in shape, and in this embodiment, an example in which a rectangular radiation conductor plate 14 is used will be described.

[0116] The radiating conductor plate 14 includes any of a metal material, a metal alloy, a hardened metal paste, and a conductive polymer. Metal materials include copper, silver, palladium, gold, platinum, aluminum, chromium, nickel, cadmium-lead, selenium, manganese, tin, vanadium, lithium, cobalt, and titanium. Alloys include multiple metal materials. Metal pastes include powders of metal materials kneaded with an organic solvent and a binder. Binders include epoxy resins, polyester resins, polyimide resins, polyamide-imide resins, and polyetherimide resins. Conductive polymers include polythiophene-based polymers, polyacetylene-based polymers, polyaniline-based polymers, and polypyrrole-based polymers.

[0117] 1, the microstrip antenna 10 of this embodiment has a radiating conductor plate 14 with a length L and a width W, and resonates at a frequency where L is an integer multiple of 1 / 2 wavelength. When using a dielectric substrate 12 with a high dielectric constant as in this embodiment, the thickness h of the dielectric substrate 12 and the width W of the radiating conductor plate 14 are designed to be sufficiently small compared to the wavelength.

[0118] The ground conductor plate 16 is a thin plate made of a highly conductive metal such as copper, silver, gold, etc. Its thickness is sufficiently thin compared to the central operating frequency of the antenna device, and may be approximately 1 / 50 to 1 / 1000 of the wavelength of the central operating frequency.

[0119] The feeding methods for microstrip antennas include direct feeding methods such as back-coaxial feeding and coplanar feeding, and electromagnetic coupling feeding methods such as slot coupling feeding and proximity coupling feeding. The rear coaxial feed can feed power from the rear of the antenna to the radiation conductor plate 14 using a coaxial line or connector that penetrates the ground conductor plate 16 and the dielectric substrate 12. The coplanar feed can feed the radiating conductor plate 14 with a microstrip line (not shown) arranged on the same plane as the radiating conductor plate 14 .

[0120] In the slot-coupled feed, another dielectric substrate (not shown) is provided sandwiching the ground conductor plate 16, and the radiating conductor plate 14 and the microstrip line are formed on separate dielectric substrates. The radiating conductor plate 14 is excited by electromagnetically coupling the radiating conductor plate 14 and the microstrip line through a slot opened in the ground conductor plate 16.

[0121] In proximity coupling feeding, the dielectric substrate 12 has a laminated structure, and a dielectric substrate on which the radiating conductor plate 14 is formed is laminated with a dielectric substrate on which the strip conductor of the microstrip line and the ground conductor plate 16 are arranged.The strip conductor of the microstrip line is extended to the bottom of the radiating conductor plate 14, and the radiating conductor plate 14 and the microstrip line are electromagnetically coupled, thereby exciting the radiating conductor plate 14.

[0122] 2(a) and 2(b) show other embodiments of the microstrip antenna. Note that the same components as those in FIG. 1 are given the same reference numerals and their explanations will be omitted where appropriate.

[0123] 2(a), the microstrip antenna 20 includes a dielectric substrate 22, a radiating conductor plate 14 provided on one surface of the dielectric substrate 22, a ground conductor plate 16 provided on the other surface of the dielectric substrate 22, and a high-dielectric substrate (high dielectric) 24 arranged opposite the radiating conductor plate 14. The dielectric substrate 22 and the radiating conductor plate 14 can be configured to be spaced a predetermined distance apart from the high-dielectric substrate 24 via a spacer 26.

[0124] The dielectric substrate 22 is made of a substrate with a low dielectric constant, such as a Teflon substrate. The high dielectric substrate 24 is made of a dielectric substrate obtained by curing the above-mentioned resin composition. The gap between the dielectric substrate 22 and the high-dielectric substrate 24 may be empty or may be filled with a dielectric material. Also, as shown in a microstrip antenna 20' in FIG. 2(b), a structure in which a high dielectric substrate 24 is in contact with the upper surface of the radiation conductor plate 14 can be used.

[0125] <Dielectric waveguide> In this embodiment, the dielectric waveguide includes a dielectric obtained by curing the thermosetting resin composition of this embodiment and a conductor film covering the surface of the dielectric. The dielectric waveguide confines and transmits electromagnetic waves in a dielectric (dielectric medium). The conductive film can be made of a metal such as copper, or a high-temperature oxide superconductor.

[0126] <Electromagnetic wave absorber> In this embodiment, the electromagnetic wave absorber has a structure in which a support, a resistive film, a dielectric layer, and a reflective layer are laminated, and can be used as a λ / 4 type electromagnetic wave absorber with high electromagnetic wave absorption performance.

[0127] The support may be a resin substrate, etc. The support can protect the resistive film and enhance the durability of the radio wave absorber. Examples of the resistive film include indium tin oxide and molybdenum-containing resistive films. The dielectric layer is formed by curing the thermosetting resin composition of this embodiment, and has a thickness of approximately 10 μm to 2000 μm.

[0128] The reflective layer can function as a layer that reflects radio waves, and may be, for example, a metal film. Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention. [Example]

[0129] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0130] (Examples 1 to 6, Comparative Example 1) The following raw materials were mixed in the amounts shown in Table 1 using a mixer at room temperature, and then roll-kneaded at 70 to 100°C. The resulting kneaded mixture was then cooled and pulverized to obtain a granular thermosetting resin composition. The mixture was then tableted under high pressure to obtain a tablet-shaped thermosetting resin composition.

[0131] (inorganic filler) Inorganic filler 1: Fused spherical silica (average particle size 31 μm, manufactured by Denka Co., Ltd.) Inorganic filler 2: Fused spherical silica (average particle size 0.5 μm, manufactured by Admatechs Co., Ltd.) Inorganic filler 3: Fused spherical silica (average particle size 1.5 μm, manufactured by Admatechs Co., Ltd.) High dielectric constant filler 1: calcium titanate (average particle size 2.0 μm) High dielectric constant filler 2: calcium titanate (spherical, average particle size 3.8 μm)

[0132] (coupling agent) Coupling agent 1: N-phenyl-3-aminopropyltrimethoxysilane (CF4083, Toyobo, Japan) Coupling agent 2: 3-mercaptopropyltrimethoxysilane (Sila-Ace, manufactured by JNC Corporation)

[0133] (thermosetting resin) Epoxy resin 1: phenol aralkyl epoxy resin containing biphenylene skeleton (NC3000L, manufactured by Nippon Kayaku Co., Ltd.)

[0134] (hardening agent) Hardener 1: Active ester hardener prepared according to the following method: (Method for preparing active ester curing agent) A flask equipped with a thermometer, dropping funnel, condenser, fractionating column, and stirrer was charged with 203.0 g of 1,3-benzenedicarboxylic acid dichloride (molar number of acid chloride groups: 2.0 mol) and 1,338 g of toluene. The system was then vacuum-purged with nitrogen to dissolve the reactants. Next, 96.5 g (0.67 mol) of α-naphthol and 219.5 g of dicyclopentadiene phenol resin (molar number of phenolic hydroxyl groups: 1.33 mol) were charged, and the system was vacuum-purged with nitrogen to dissolve the reactants. Subsequently, while purging with nitrogen gas, the system was maintained at 60°C or below, and 400 g of 20% aqueous sodium hydroxide solution was added dropwise over 3 hours. Stirring was continued under these conditions for 1.0 hour. After the reaction was completed, the mixture was allowed to stand, allowing the liquid to separate, and the aqueous layer was removed. Water was then added to the toluene phase containing the dissolved reactants, and the mixture was stirred and mixed for approximately 15 minutes. The mixture was then allowed to stand, allowing the liquid to separate, and the aqueous layer was removed. This procedure was repeated until the pH of the aqueous layer reached 7. The water was then removed by decanting, yielding an activated ester resin in the form of a toluene solution with a nonvolatile content of 65%. The structure of the resulting activated ester resin was confirmed to be R 1 and R 3 The active ester resin had a structure in which π was a hydrogen atom, Z was a naphthyl group, and l was 0. The average value k of the repeating units of the active ester resin was calculated from the reaction equivalent ratio and was in the range of 0.5 to 1.0. The active ester resin obtained specifically had a structure represented by the following chemical formula: In the formula below, the average value k of the repeating units was 0.5 to 1.0.

[0135] [ka]

[0136] (catalyst) Catalyst 1: Tetraphenylphosphonium-4,4'-sulfonyldiphenolate Catalyst 2: Tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenylsilicate

[0137] (mold release agent) Release agent 1: Glycerin trimontanate ester (Licorb WE-4, Clariant Japan)

[0138] (coloring agent) Titanium dioxide: average particle size D 50 :0.6μm Mixture of titanium nitride and titanium oxide: 50% by mass of titanium nitride, 50% by mass of titanium oxide, average particle size D 50 :0.1μm

[0139] (Spiral Flow) Using a low-pressure transfer molding machine (KTS-15 manufactured by Kotaki Seiki Co., Ltd.), the obtained thermosetting resin composition was injected into a mold for spiral flow measurement in accordance with EMMI-1-66 under conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds, and the flow length was measured.

[0140] (Evaluation of dielectric constant and dielectric loss tangent using the cavity resonator method) First, a test piece was obtained using the resin composition. Specifically, the obtained thermosetting resin composition was applied to a Si substrate and pre-baked at 120° C. for 4 minutes to form a resin film with a coating thickness of 12 μm. This was heated in an oven at 200°C for 90 minutes in a nitrogen atmosphere and then treated with hydrofluoric acid (immersed in a 2% by mass aqueous solution of hydrofluoric acid). After removing the substrate from the hydrofluoric acid, the cured film was peeled off from the Si substrate to prepare a test specimen. The measurement equipment used was a network analyzer HP8510C, a synthesized sweeper HP83651A, and a test set HP8517B (all manufactured by Agilent Technologies). These equipment and a cylindrical cavity resonator (inner diameter φ42 mm, height 30 mm) were set up. The resonant frequency, 3 dB bandwidth, and transmitted power ratio were measured at a frequency of 1 MHz with and without a test piece inserted in the resonator. These measurement results were then analytically calculated using software to determine the dielectric properties of the permittivity (Dk) and dielectric loss tangent (Df). The measurement mode was TE. 011 Mode.

[0141] <Evaluation of color (blackness)> The obtained thermosetting resin composition was cured by compression molding under conditions of a molding temperature of 175°C, a curing time of 100 seconds, and a molding pressure of 8 MPa to obtain a rectangular cured product. L of the surface of the cured product * value, a * value and b * was measured using a Color Reader CR-13 (manufactured by Konica Minolta Sensing, Inc.) The colors of the cured products obtained from the thermosetting resin compositions of Comparative Example 1 and Examples 1 to 5 are shown in FIG.

[0142] [Table 1]

[0143] The results in Table 1 reveal that the thermosetting resin compositions of the examples according to the present invention can provide cured products with high dielectric constants, low dielectric loss tangents, and excellent color (blackness). In other words, the cured products obtained from the thermosetting resin compositions of the examples had an excellent balance of high dielectric constants, low dielectric loss tangents, and color (blackness). [Explanation of symbols]

[0144] 10 Microstrip Antenna 12 Dielectric substrate 14 Radiating conductor plate 16 Ground conductor plate 20, 20' Microstrip Antenna 22 Dielectric substrate 24 High dielectric substrate 26 spacer a Cavity

Claims

1. (A) a thermosetting resin; (B) an inorganic filler containing a high dielectric filler (B1); (C) titanium nitride; A thermosetting resin composition comprising:

2. 2. The thermosetting resin composition according to claim 1, wherein the high dielectric filler (B1) comprises at least one selected from calcium titanate, strontium titanate, magnesium titanate, magnesium zirconate, strontium zirconate, bismuth titanate, zirconium titanate, zinc titanate, barium zirconate, calcium titanate zirconate, lead titanate zirconate, barium magnesium niobate, and calcium zirconate.

3. The thermosetting resin composition according to claim 1 , wherein the high dielectric filler (B1) comprises calcium titanate.

4. The thermosetting resin composition according to claim 1 , further comprising titanium oxide (D).

5. 5. The thermosetting resin composition according to claim 4, wherein the total amount of the titanium nitride (C) and the titanium oxide (D) is 0.1% by mass or more and 8% by mass or less, relative to 100% by mass of the entire thermosetting resin composition.

6. In a total of 100 mass% of titanium nitride (C) and titanium oxide (D), Titanium nitride (C) is 35% by weight or more and 75% by mass or less, and The thermosetting resin composition according to claim 4, comprising titanium oxide (D) in an amount of 25% by weight or more and 65% by mass or less.

7. 2. The thermosetting resin composition according to claim 1, wherein the titanium nitride (C) has an average particle size of 0.01 μm to 5 μm.

8. 2. The thermosetting resin composition according to claim 1, wherein the high dielectric filler (B1) is contained in an amount of 20% by volume or more and 95% by volume or more relative to 100% by volume of the inorganic filler (B).

9. The thermosetting resin composition according to claim 1 , further comprising a curing agent (E).

10. The curing agent (E) comprises an active ester curing agent (E1), 10. The thermosetting resin composition according to claim 9, wherein the active ester curing agent (E1) comprises at least one selected from the group consisting of an active ester curing agent containing a dicyclopentadiene-type diphenol structure, an active ester curing agent containing a naphthalene structure, an active ester curing agent containing an acetylated product of phenol novolac, and an active ester curing agent containing a benzoylated product of phenol novolac.

11. The thermosetting resin composition according to claim 10, wherein the active ester curing agent (E1) has a structure represented by the following general formula (1): 【Chemistry 1】 In general formula (1), A represents a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group, and Ar′ represents a substituted or unsubstituted aryl group. B is a structure represented by the following general formula (B): 【Chemistry 2】 (In general formula (B), Ar is a substituted or unsubstituted arylene group; Y is a single bond, a substituted or unsubstituted linear alkylene group having 1 to 6 carbon atoms, or a substituted or unsubstituted cyclic alkylene group having 3 to 6 carbon atoms, a substituted or unsubstituted divalent aromatic hydrocarbon group, an ether bond, a carbonyl group, a carbonyloxy group, a sulfide group, or a sulfone group; and n is an integer of 0 to 4.) k is the average value of the repeating units and is in the range of 0.25 to 3.

5.

12. The thermosetting resin composition according to claim 1 , further comprising a curing catalyst (F).

13. L of the cured product of the thermosetting resin composition ＊ a ＊ b ＊ In color coordinates, Lightness L ＊ The value of is between 24 and 47, a ＊ The value of is −3.0 to 0.0, b ＊ The thermosetting resin composition according to claim 1, wherein the value of is −6.0 to −1.

5.

14. The thermosetting resin composition according to any one of claims 1 to 13, which is used as a material for forming a microstrip antenna.

15. The thermosetting resin composition according to any one of claims 1 to 13, which is used as a material for forming a dielectric waveguide.

16. The thermosetting resin composition according to any one of claims 1 to 13, which is used as a material for forming an electromagnetic wave absorber.

17. A dielectric substrate comprising a cured product of the thermosetting resin composition according to any one of claims 1 to 13.

18. The dielectric substrate according to claim 17; a radiation conductor plate provided on one surface of the dielectric substrate; a ground conductor plate provided on the other surface of the dielectric substrate; A microstrip antenna comprising:

19. a dielectric substrate; a radiation conductor plate provided on one surface of the dielectric substrate; a ground conductor plate provided on the other surface of the dielectric substrate; a high dielectric material disposed opposite the radiation conductor plate; A microstrip antenna comprising: A microstrip antenna, wherein the high dielectric is constituted by the dielectric substrate according to claim 17.

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