Thermosetting resin composition, dielectric substrate, and microstrip antenna

Abstract

The present invention provides a thermosetting resin composition that yields a cured product (dielectric substrate) with excellent high dielectric constant and low dielectric loss tangent, a dielectric substrate made from the resin composition, and a microstrip antenna equipped with the dielectric substrate. [Solution] The thermosetting resin composition of the present invention comprises (A) a thermosetting resin, (B) a high dielectric constant filler, and (C) a coupling agent represented by the following general formula (1), wherein the high dielectric constant filler (B) comprises at least one selected from calcium titanate, strontium titanate, barium titanate, magnesium titanate, and titanium oxide. TIFF2026111704000022.tif16153

Description

[Technical Field]

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

[0002] In recent years, wireless communication has become faster, and there is a growing demand for higher performance and smaller size in the communication equipment used. Furthermore, the capacity of wireless communication has been rapidly increasing, and the frequency bands used for transmission signals are rapidly becoming wider and higher. As a result, the frequency bands used by communication equipment can no longer be met by the conventional microwave band and are expanding to the millimeter wave band. Against this backdrop, there is a strong demand for higher performance antennas mounted on communication equipment.

[0003] Communication devices can be further miniaturized if the dielectric constant of the antenna material (dielectric substrate) incorporated inside the device is high. Furthermore, a lower dielectric loss tangent of the dielectric substrate results in lower losses, which is advantageous for higher frequencies. Therefore, using a dielectric substrate with a high dielectric constant and low dielectric loss tangent allows for higher frequencies, shorter circuits, and smaller communication devices.

[0004] Patent Document 1 discloses a molding resin composition comprising an epoxy resin, a curing agent, and an inorganic filler containing at least one selected from the group consisting of calcium titanate particles and strontium titanate particles, wherein the total content of the calcium titanate particles and the strontium titanate particles is 30% by volume or more and less than 60% by volume of the entire inorganic filler. In the examples of the said document, N-phenyl-3-aminopropyltrimethoxysilane is used as a coupling agent. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-092991 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, dielectric substrates obtained from the resin composition described in Patent Document 1 have problems with high dielectric constant and low dielectric loss tangent, and these problems were particularly pronounced in the high-frequency band. [Means for solving the problem]

[0007] The inventors of the present invention have found that the above problems can be solved by using a predetermined coupling agent that does not have a polar group at one end, and have completed the present invention. In other words, the present invention can be described as follows. [1] (A) Thermosetting resin and (B) High dielectric constant filler, (C) A coupling agent represented by the following general formula (1), Includes, A thermosetting resin composition wherein the high dielectric constant filler (B) comprises at least one selected from calcium titanate, strontium titanate, barium titanate, magnesium titanate, and titanium oxide. [ka] (In general formula (1), m is 2 or 3, R 1 R represents a methoxy group or an ethoxy group, and there are multiple R groups. 1 These may be the same or different. Q represents a hydrogen atom, a phenyl group, an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 3 to 12 carbon atoms. Multiple Qs may be the same or different. [2] The thermosetting resin composition according to [1], wherein the thermosetting resin (A) comprises an epoxy resin. [3] The thermosetting resin composition according to [1] or [2], wherein the high dielectric constant filler (B) comprises calcium titanate. [4] A thermosetting resin composition according to any one of [1] to [3], further comprising an active ester curing agent (D). [5] The thermosetting resin composition according to [4], wherein the active ester curing agent (D) comprises at least one selected from 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 phenol novolac, and an active ester curing agent containing a benzoylated phenol novolac. [6] The thermosetting resin composition according to [5], wherein the active ester curing agent (D) has a structure represented by the following general formula (2). [ka] (In general formula (2), A is a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group, and 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 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, 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. n is an integer from 0 to 4.) k is the average value of the repeating units, ranging from 0.25 to 3.5. [7] A thermosetting resin composition according to any one of [1] to [6], further comprising a curing catalyst (E). [8] A thermosetting resin composition according to any one of [1] to [7], used as a material for forming a microstrip antenna. [9] A thermosetting resin composition according to any one of [1] to [7], used as a material for forming a dielectric waveguide.

[10] A thermosetting resin composition according to any one of [1] to [7], used as a material for forming an electromagnetic wave absorber.

[11] A dielectric substrate made of a cured product of a thermosetting resin composition described in any of [1] to [7].

[12]

[11] The dielectric substrate described above, A radiating conductor plate provided on one side of the dielectric substrate, A ground conductor plate provided on the other side of the dielectric substrate, A microstrip antenna equipped with the following features.

[13] Dielectric substrate and, A radiating conductor plate provided on one side of the dielectric substrate, A ground conductor plate provided on the other side of the dielectric substrate, A high dielectric material is arranged opposite the aforementioned radiating conductor plate, A microstrip antenna comprising, A microstrip antenna in which the high dielectric material is made of the dielectric substrate described in

[11] . [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a thermosetting resin composition that yields a cured product (dielectric substrate) with excellent high dielectric constant and low dielectric loss tangent, a dielectric substrate made from the resin composition, and a microstrip antenna equipped with the dielectric substrate. In other words, the dielectric substrate obtained from the thermosetting resin composition of the present invention has an excellent balance between high dielectric constant and low dielectric loss tangent. [Brief explanation of the drawing]

[0009] [Figure 1] This is a top perspective view showing the microstrip antenna of this embodiment. [Figure 2] This is a cross-sectional view showing another embodiment of the microstrip antenna of this embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted as appropriate. Also, for example, "1 to 10" represents "1 or more" to "10 or less" unless otherwise specified.

[0011] The thermosetting resin composition of this embodiment comprises (A) a thermosetting resin, (B) a high dielectric constant filler, and (C) a coupling agent represented by the following general formula (1). The high dielectric constant filler (B) comprises at least one selected from calcium titanate, strontium titanate, barium titanate, magnesium titanate, and titanium oxide.

[0012] According to the thermosetting resin composition of the present invention, it is possible to provide a dielectric substrate with excellent high dielectric constant and low dielectric loss tangent, a dielectric substrate, and a microstrip antenna equipped with the dielectric substrate. In other words, the dielectric substrate obtained from the thermosetting resin composition of the present invention has an excellent balance between high dielectric constant and low dielectric loss tangent.

[0013] [Thermosetting resin (A)] In this embodiment, the thermosetting resin (A) can be one or more selected from cyanate resins, epoxy resins, resins having two or more radically polymerizable carbon-carbon double bonds in one molecule, and maleimide resins. Among these, epoxy resin (A1) is particularly preferred from the viewpoint of improving the effects of the present invention and the adhesion of the thermally conductive paste.

[0014] The epoxy resin (A1) can use any monomer, oligomer, or polymer having two or more epoxy groups in a single molecule, and its molecular weight and molecular structure are not limited.

[0015] Epoxy resins (A1) include, for example, biphenyl-type epoxy resins; bisphenol-type epoxy resins such as bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, and tetramethylbisphenol F-type epoxy resin; stilbene-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resin and cresol novolac-type epoxy resin; polyfunctional epoxy resins such as triphenolmethane-type epoxy resin and trisphenol-type epoxy resin, exemplified by alkyl-modified triphenolmethane-type epoxy resin; phenol aralkyl-type epoxy resins having a phenylene skeleton; naphthol aralkyl-type epoxy resins having a phenylene skeleton. The material comprises one or more types selected from the group consisting of epoxy resins, phenol aralkyl type epoxy resins having a biphenylene skeleton, naphthol aralkyl type epoxy resins having a biphenylene skeleton, etc.; naphthol type epoxy resins such as dihydroxynaphthalene type epoxy resins and epoxy resins obtained by glycidyl etherification of a dimer of dihydroxynaphthalene; 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.

[0016] From the viewpoint of the effects of the present invention, among these, novolac-type epoxy resins, polyfunctional epoxy resins, and phenol aralkyl-type epoxy resins can be preferably used. Also, from a similar viewpoint, the epoxy resin preferably contains one or more selected from the group consisting of orthocresol novolac-type epoxy resins, phenol aralkyl-type epoxy resins having a biphenylene skeleton, and triphenylmethane-type epoxy resins, and more preferably contains one or more selected from the group consisting of orthocresol novolac-type epoxy resins and phenol aralkyl-type epoxy resins having a biphenylene skeleton.

[0017] From the viewpoint of the effects of the present invention, the epoxy resin (A1) may preferably be present in an amount of 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, relative to the total thermosetting resin composition. Typically, the epoxy resin (A1) may be present in an amount of 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0018] [High dielectric constant filler (B)] In this embodiment, the high dielectric constant filler (B) can be calcium titanate, strontium titanate, barium titanate, magnesium titanate, titanium oxide, etc., and one or more selected from these can be used.

[0019] The thermosetting resin composition of this embodiment, by containing these high dielectric constant fillers (B), exhibits excellent high dielectric constant and low dielectric loss tangent, and these effects are also excellent in the high-frequency band. As the high dielectric constant filler (B), calcium titanate is more preferred from the viewpoint of the effects of the present invention, and especially from the viewpoint of low dielectric loss tangent.

[0020] The shape of the high dielectric constant filler (B) can be granular, amorphous, or flake-like, and these shapes of high dielectric constant fillers can be used in any ratio. From the viewpoint of the effects of the present invention and from the viewpoint of fluidity and packing performance, the average particle size of the high dielectric constant filler is preferably 0.1 μm to 50 μm, more preferably 0.3 μm to 20 μm, and even more preferably 0.5 μm to 10 μm.

[0021] The amount of high dielectric constant filler (B) can be preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, relative to the total thermosetting resin composition. Alternatively, it can preferably be 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. When the amount of high dielectric constant filler (B) added is within the above range, the dielectric loss tangent of the resulting cured product is lower, and the manufacturing of molded articles is also superior.

[0022] [Coupling agent (C)] The thermosetting resin composition of this embodiment contains a coupling agent (C) represented by general formula (1).

[0023] [ka]

[0024] In general formula (1), m is either 2 or 3. R 1 R represents a methoxy group or an ethoxy group, and there are multiple R groups. 1 These may be the same or different.

[0025] Q represents a hydrogen atom, a phenyl group, an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 3 to 12 carbon atoms. Multiple Qs may be the same or different.

[0026] Examples of alkyl groups having 1 to 12 carbon atoms include linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and n-nonyl group.

[0027] Examples of cycloalkyl groups having 3 to 12 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclodecyl, cycloundecyl, and cyclododecyl groups.

[0028] The thermosetting resin composition of this embodiment, by including a coupling agent (C), can produce a cured product (dielectric substrate) that exhibits excellent low dielectric loss tangent and high dielectric constant. In other words, the thermosetting resin composition of this embodiment can produce a cured product (dielectric substrate) that has an excellent balance between low dielectric loss tangent and high dielectric constant.

[0029] As a coupling agent (C), Dimethoxymethylsilane, dimethoxydimethylsilane, dimethoxydiethylsilane, dimethoxydiisobutylsilane, Diethoxymethylsilane, diethoxydimethylsilane, diethoxydiethylsilane,

[0030] Trimethoxysilane, trimethoxymethylsilane, trimethoxyethylsilane, trimethoxypropylsilane, trimethoxyhexylsilane, trimethoxydecylsilane, trimethoxyphenylsilane, dimethoxydiphenylsilane, cyclohexyltrimethoxysilane, cyclopentyltrimethoxysilane, dicyclopentyldimethoxysilane, trimethoxyhexylsilane, Triethoxysilane, triethoxymethylsilane, triethoxyethylsilane, Examples include triethoxypropylsilane, triethoxybutylsilane, triethoxyhexylsilane, triethoxyoctylsilane, and triethoxyphenylsilane, and these can be used individually or in combination of two or more. In this embodiment, trimethoxyphenylsilane, trimethoxysilane, or triethoxymethylsilane are preferred as the coupling agent (C).

[0031] From the viewpoint of compatibility between inorganic fillers such as high dielectric constant fillers and resin components, and dispersibility with respect to resin components, coupling agents have a structure in which polar groups are provided at their ends. Although the presence of polar groups improves the dielectric loss tangent, it was difficult to create a structure without polar groups from the above viewpoint. Therefore, by using a coupling agent having a structure in which polar groups are provided at only one end, and bonding the coupling agent to the surface of the high dielectric constant filler via these polar groups, it was possible to reduce the dielectric loss tangent without reducing compatibility or dispersibility, thus completing the present invention.

[0032] In this embodiment, the coupling agent (C) may be mixed with each component when preparing the thermosetting resin composition, or a surface-treated product in which the surface of the high dielectric constant filler (B) is treated with the coupling agent (C) may be used.

[0033] The amount of coupling agent (C) can be preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and even more preferably 0.10% by mass or more, relative to the total thermosetting resin composition. It can also preferably be 5.0% by mass or less, more preferably 3.0% by mass or less, and even more preferably 1.0% by mass or less. When the amount of coupling agent (C) is within the above range, the dielectric loss tangent of the resulting cured product can be further reduced, and the dielectric constant can also be improved.

[0034] [Activated ester curing agent (D)] The thermosetting resin composition of this embodiment may contain an active ester curing agent (D).

[0035] As the active ester curing agent (D), a compound having one or more active ester groups in one molecule can be used. In particular, as the active ester curing agent (D), compounds 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, are preferred.

[0036] Preferred specific examples of the active ester curing agent (D) 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 phenol novolac, or active ester curing agents containing a benzoylated 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. "Dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

[0037] In this embodiment, the active ester curing agent (D) may have a structure represented by the following general formula (2).

[0038] [ka]

[0039] In general formula (2), "B" is the structure represented by general formula (B).

[0040] [ka]

[0041] In general formula (B), Ar is a substituted or unsubstituted arylene group. Substituents for the substituted arylene group include alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, phenyl groups, aralkyl groups, etc.

[0042] 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 group include alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, phenyl groups, aralkyl groups, etc.

[0043] Preferred Y includes single bonds, methylene groups, -CH(CH3)2-, ether bonds, optionally substituted cycloalkylene groups, optionally substituted 9,9-fluorenylene groups, and the like. n is an integer between 0 and 4, preferably 0 or 1.

[0044] Specifically, B is a structure represented by the following general formula (B1) or the following general formula (B2).

[0045] [ka]

[0046] In the above general formulas (B1) and (B2), Ar and Y are equivalent to those in 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.

[0047] The thermosetting resin composition of this embodiment, by containing a specific active ester curing agent, can produce a cured product with excellent dielectric properties and superior low dielectric loss tangent.

[0048] The activated ester curing agent (D) used in the thermosetting resin composition of this embodiment has an activated ester group represented by formula (B). In the curing reaction between the epoxy resin and the activated ester curing agent, the activated ester group of the activated ester curing agent reacts with the epoxy group of the epoxy resin to produce a secondary hydroxyl group. This secondary hydroxyl group is sequestered by the ester residue of the activated ester curing agent. As a result, the dielectric loss tangent of the cured product is reduced. In one embodiment, the structure represented by formula (B) is preferably at least one selected from the following formulas (B-1) to (B-6).

[0049] [ka]

[0050] In equations (B-1) to (B-6), R 1 Each of these is 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.

[0051] R 2 Each of these is independently an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a phenyl group, and X is one of a linear alkylene group having 2 to 6 carbon atoms, an ether bond, a carbonyl group, a carbonyloxy group, a sulfide group, or a sulfone group. n is an integer between 0 and 4, and p is an integer between 1 and 4.

[0052] The structures represented by formulas (B-1) to (B-6) above are all highly oriented structures. Therefore, when an active ester curing agent containing these structures is used, the resulting thermosetting resin composition has a low dielectric loss tangent and excellent adhesion to metals, making it suitable for use as a semiconductor encapsulating material.

[0053] In particular, from the viewpoint of low dielectric loss tangent, activated ester curing agents having structures represented by formula (B-2), formula (B-3), or formula (B-5) are preferred, and more preferably activated ester curing agents having a structure in formula (B-2) where n is 0, a structure in formula (B-3) where X is an ether bond, or a structure in formula (B-5) where the two carbonyloxy groups are at the 4,4'-position. Also, R in each formula 1 Preferably, all of them are hydrogen atoms.

[0054] In formula (2), "Ar'" is an aryl group, and can be, for example, 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 because it yields a cured product with particularly low dielectric loss tangent.

[0055] In this embodiment, "A" in the active ester curing agent represented by formula (2) is a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group. Examples of such arylene groups include structures obtained by polyaddition of an unsaturated aliphatic cyclic hydrocarbon compound containing two double bonds in one molecule with a phenolic compound.

[0056] Examples of unsaturated aliphatic cyclic hydrocarbon compounds containing two double bonds in one molecule include dicyclopentadiene, cyclopentadiene polymers, tetrahydroindene, 4-vinylcyclohexene, 5-vinyl-2-norbornene, and limonene. These may be used individually or in combination of two or more. Among these, dicyclopentadiene is preferred because it yields a cured product with excellent heat resistance. Since dicyclopentadiene is found in petroleum fractions, industrial dicyclopentadiene may contain cyclopentadiene polymers or other aliphatic or aromatic diene compounds as impurities. However, considering performance such as heat resistance, curability, and moldability, it is desirable to use a product with a dicyclopentadiene purity of 90% by mass or higher.

[0057] On the other hand, examples of the phenolic compounds include phenol, cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorphenol, bromuphenol, 1-naphthol, 2-naphthol, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, etc., and each may be used alone or two or more may be used in combination. Among these, phenol is preferred because it is an active ester curing agent with high curability and excellent dielectric properties in the cured product.

[0058] In a preferred embodiment, "A" in the active ester curing agent represented by formula (2) has the structure represented by formula (A). A thermosetting resin composition containing an active ester curing agent in which "A" in formula (2) has the following structure has a cured product with a low dielectric loss tangent and excellent adhesion to inserts.

[0059] [ka]

[0060] In formula (A), R 3 is each independently either 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.

[0061] Among the active ester curing agents represented by formula (2), more preferable ones include resins represented by the following formula (1-1), formula (1-2), and formula (1-3), and particularly preferable ones include the resin represented by the following formula (1-3).

[0062]

Chemical formula

[0063] In formula (1-1), R 1 and R 3 are each independently either 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.

[0064]

Chemical formula

[0065] In formula (1-2), R 1 and R 3 are each independently either 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.

[0066] [ka]

[0067] In formula (1-3), R 1 and R 3 Each of these is 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 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, ranging from 0.25 to 3.5.

[0068] The active ester curing agent (D) used in the present invention can be produced by a known method of reacting a phenolic compound (a) having a structure in which multiple aryl groups having phenolic hydroxyl groups are bonded via an aliphatic cyclic hydrocarbon group, an aromatic kernel-containing dicarboxylic acid or its halide (b), and an aromatic monohydroxy compound (c).

[0069] The reaction ratio of the phenolic compound (a), the aromatic kernel-containing dicarboxylic acid or its halide (b), and the aromatic monohydroxy compound (c) can be appropriately adjusted according to the desired molecular design. In particular, to obtain a highly curable active ester curing agent, it is preferable to use each raw material in a ratio such that, for every 1 mole of carboxyl groups or acid halide groups of the aromatic kernel-containing dicarboxylic acid or its halide (b), 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. It is even more preferable to use each raw material 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.

[0070] Furthermore, the functional group equivalent of the active ester curing agent (D) is preferably in the range of 200 g / eq to 230 g / eq, and more preferably in the range of 210 g / eq to 220 g / eq, because when the total number of functional groups in the resin is the sum of the arylcarbonyloxy groups and phenolic hydroxyl groups in the resin structure, a cured product with excellent curability and low dielectric constant and dielectric loss tangent can be obtained.

[0071] In the thermosetting resin composition of this embodiment, the ratio of the active ester curing agent (D) to the epoxy resin (A1) is preferably such that the epoxy groups in the epoxy resin (A1) are 0.8 to 1.2 equivalents for every 1 equivalent of the active groups in the active ester curing agent (D), in order to obtain a cured product with excellent curability and low dielectric loss tangent. Here, the active groups in the active ester curing agent (D) refer to the arylcarbonyloxy groups and phenolic hydroxyl groups present in the resin structure.

[0072] In the composition of this embodiment, the active ester curing agent (D) is used in an amount of preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 2.0% by mass or more, relative to the entire thermosetting resin composition. It is also used in an amount of preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 7% by mass or less. By including the active ester curing agent (D) within the above range, the resulting cured product can have superior dielectric properties, exhibiting even better low dielectric loss tangent and higher dielectric constant.

[0073] The resin inhibitor of this embodiment, by using a combination of an active ester curing agent (D) and the above-mentioned high dielectric constant filler (B), exhibits superior high dielectric constant and low dielectric loss tangent, and these effects are also excellent in the high-frequency band.

[0074] From the viewpoint of the above effects, the active ester curing agent (D) can be included in an amount of preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and even more preferably 3 to 15 parts by mass, per 100 parts by mass of the high dielectric constant filler (B) described above.

[0075] [Curing catalyst (E)] The thermosetting resin composition of this embodiment may further contain a curing catalyst (E). The curing catalyst (E) is sometimes called a curing accelerator. The curing catalyst (E) is not particularly limited as long as it accelerates the curing reaction of the thermosetting resin (A), and any known curing catalyst can be used.

[0076] Specifically, examples include phosphorus atom-containing compounds such as organophosphines, tetrasubstituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds; imidazoles such as 2-methylimidazole and 2-phenylimidazole (imidazole-based curing accelerators); and nitrogen atom-containing compounds such as amidines and tertiary amines, and quaternary salts of amidines and amines, exemplified by 1,8-diazabicyclo[5.4.0]undecene-7 and benzyldimethylamine. Only one type may be used, or two or more types may be used.

[0077] Among these, from the viewpoint of improving curability and obtaining a magnetic material with excellent mechanical strength such as bending strength, it is preferable to include a phosphorus atom-containing compound, and more preferably to include latent compounds such as tetrasubstituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds, with tetrasubstituted phosphonium compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds being particularly preferred.

[0078] By using an activated ester curing agent (D) represented by general formula (2) in combination with a latent curing catalyst, a magnetic material with superior moldability and superior mechanical strength, such as bending strength, can be obtained.

[0079] 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. Examples of tetrasubstituted phosphonium compounds include compounds represented by the following general formula (6).

[0080] [ka]

[0081] In general formula (6), P represents the phosphorus atom. R 4 , R 5 , R 6 and R 7 Each of these independently represents an aromatic group or an alkyl group. A represents an anion of an aromatic organic acid having at least one functional group selected from a hydroxyl group, a carboxyl group, or a thiol group on its aromatic ring. AH represents an aromatic organic acid having at least one functional group selected from a hydroxyl group, a carboxyl group, or a thiol group on its aromatic ring. x and y are between 1 and 3, z is between 0 and 3, and x = y. Compounds represented by general formula (6) can be obtained, for example, as follows.

[0082] First, a tetrasubstituted phosphonium halide, an aromatic organic acid, and a base are mixed uniformly in an organic solvent to generate an aromatic organic acid anion in the solution system. Then, water is added to precipitate the compound represented by general formula (6). In the compound represented by general formula (6), R is bonded to the phosphorus atom. 4 , R 5 , R 6 and R 7Preferably, AH is a phenyl group, AH is a compound having a hydroxyl group in the aromatic ring, i.e., a phenol, and A is the anion of the phenol. Examples of the phenols 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. Examples of phosphobetaine compounds include those represented by the following general formula (7).

[0083] [ka]

[0084] In general formula (7), P represents the phosphorus atom. R 8 R is an alkyl group having 1 to 3 carbon atoms. 9 The symbol represents a hydroxyl group. f is between 0 and 5, and g is between 0 and 3. Compounds represented by general formula (7) can be obtained, for example, as follows.

[0085] First, the triaromatically substituted phosphine, which is a third phosphine, is brought into contact with a diazonium salt, and the diazonium group of the triaromatically substituted phosphine is substituted for the diazonium group of the diazonium salt. Examples of adducts between phosphine compounds and quinone compounds include compounds represented by the following general formula (8).

[0086] [ka]

[0087] In general formula (8), P represents the phosphorus atom. R 10 , R11 and R 12 This represents an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, and these groups may be the same or different.

[0088] R 13 , R 14 and R 15 R represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and they may be the same or different from each other. 14 and R 15 They may be joined together to form a ring structure.

[0089] The phosphine compounds used in the adducts of phosphine compounds and quinone compounds are preferably those with an unsubstituted or substituted aromatic ring, such as triphenylphosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, trinaphthylphosphine, and tris(benzyl)phosphine. Examples of substituents such as alkyl groups and alkoxyl groups have 1 to 6 carbon atoms. Triphenylphosphine is preferred from the viewpoint of availability.

[0090] Furthermore, examples of quinone compounds used in adducts of phosphine compounds and quinone compounds include benzoquinones and anthraquinones, with p-benzoquinone being preferred in terms of storage stability.

[0091] A method for producing adducts of phosphine compounds and quinone compounds involves contacting and mixing the organic tertiary phosphine and benzoquinone compounds in a solvent in which both can be dissolved. Suitable solvents include ketones such as acetone and methyl ethyl ketone, which have low solubility in the adduct. However, the method is not limited to these.

[0092] 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 14and R 15 Compounds in which the atom is a hydrogen atom, i.e., compounds to which 1,4-benzoquinone and triphenylphosphine are added, are preferred in that they reduce the thermal modulus of the cured product of the sealing resin composition. Examples of adducts between phosphonium compounds and silane compounds include compounds represented by the following general formula (9).

[0093] [ka]

[0094] In general formula (9), P represents a phosphorus atom, and Si represents a silicon atom.

[0095] R 16 , R 17 , R 18 and R 19 Each of these represents an organic group having an aromatic ring or a heterocycle, or an aliphatic group, and they may be the same or different from one another. R 20 is, base Y 2 and Y 3 It is an organic group that bonds with [another organic group]. R 21 is, base Y 4 and Y 5 It is an organic group that bonds with [another organic group].

[0096] Y 2 and Y 3 This represents a group formed when a proton-donating group releases a proton, and the group Y is formed within the same molecule. 2 and Y 3 It combines with silicon atoms to form a chelate structure.

[0097] Y 4 and Y 5 Y represents a group formed when a proton-donating group releases a proton, and Y is a group within the same molecule. 4 and Y 5 It combines with silicon atoms to form a chelate structure. R 20 , and R21 They may be the same or different from each other, Y 2 , Y 3 , Y 4 and Y 5 They may be identical or different from one another. Z1 is an organic group having an aromatic ring or a heterocycle, or an aliphatic group.

[0098] In general formula (9), R 16 , R 17 , R 18 and R 19 Examples of such groups include phenyl, methylphenyl, methoxyphenyl, hydroxyphenyl, naphthyl, hydroxynaphthyl, benzyl, methyl, ethyl, n-butyl, n-octyl, and cyclohexyl groups. Among these, aromatic groups having substituents such as alkyl groups, alkoxy groups, or hydroxyl groups, such as phenyl, methylphenyl, methoxyphenyl, hydroxyphenyl, and hydroxynaphthyl groups, or unsubstituted aromatic groups are more preferred.

[0099] In general formula (9), R 20 Y 2 and Y 3 It is an organic group that bonds with R. 21 is, base Y 4 and Y 5 It is an organic group that bonds with Y. 2 and Y 3 Y is a group formed when a proton-donating group releases a proton, and it is a group within the same molecule. 2 and Y 3 It combines with silicon atoms to form a chelate structure. Similarly, Y 4 and Y 5 Y is a group formed when a proton-donating group releases a proton, and it is a group within the same molecule. 4 and Y 5 The group R combines with silicon atoms to form a chelate structure. 20 and R 21 The elements may be identical or different from each other, and the base Y 2 , Y 3 , Y4 and Y5 may be the same as or different from each other. The group represented by -Y 2 -R 20 -Y 3 - and Y 4 -R 21 -Y 5 - in the general formula (9) is composed of a group formed by a proton donor releasing two protons. As the proton donor, an organic acid having at least two carboxyl groups or hydroxyl groups in the molecule is preferable, and further, an aromatic compound having at least two carboxyl groups or hydroxyl groups on adjacent carbons constituting an aromatic ring is preferable, and an aromatic compound having at least two hydroxyl groups on adjacent carbons constituting an aromatic ring is more preferable. For example, catechol, pyrogallol, 1,2-dihydroxynaphthalene, 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, glycerin, etc. can be mentioned. Among these, catechol, 1,2-dihydroxynaphthalene, and 2,3-dihydroxynaphthalene are more preferable.

[0100] Z in the general formula (9) 1 represents an organic group or an aliphatic group having an aromatic ring or a heterocyclic ring. Specific examples thereof include aliphatic hydrocarbon groups such as methyl group, ethyl group, propyl group, butyl group, hexyl group, and octyl group, aromatic hydrocarbon groups such as phenyl group, benzyl group, naphthyl group, and biphenyl group, glycidyloxypropyl group, mercaptopropyl group, alkyl groups having glycidyloxy group, mercapto group, amino group, and reactive substituents such as vinyl group, etc. Among these, methyl group, ethyl group, phenyl group, naphthyl group, and biphenyl group are more preferable from the viewpoint of thermal stability. The production method of the adduct of the phosphonium compound and the silane compound is as follows, for example.

[0101] In a flask containing methanol, a silane compound such as phenyltrimethoxysilane and a proton donor such as 2,3-dihydroxynaphthalene are added and dissolved. Then, a sodium methoxide-methanol solution is added dropwise under stirring at room temperature. A pre-prepared solution of tetraphenylphosphonium bromide or other tetra-substituted phosphonium halide dissolved in methanol is then added dropwise under stirring at room temperature, causing crystals to precipitate. The precipitated crystals are filtered, washed with water, and vacuum-dried to obtain an adduct of the phosphonium compound and the silane compound.

[0102] When a curing catalyst (E) is used, its content is preferably 0.05% to 3% by mass, and more preferably 0.10% to 1.0% by mass, relative to the entire thermosetting resin composition. By setting the value within this range, a sufficient curing acceleration effect can be obtained without excessively degrading other performance characteristics.

[0103] [Inorganic fillers] The thermosetting resin composition of this embodiment may further include inorganic fillers in addition to the high dielectric constant filler (D) to reduce hygroscopicity, reduce the coefficient of linear expansion, improve thermal conductivity, and improve strength. In other words, in this embodiment, the inorganic filler does not include the high dielectric constant filler (D).

[0104] Examples of inorganic fillers 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, fossterite, steatite, spinel, mullite, and titania, or spherical beads and glass fibers made from these. These inorganic fillers may be used individually or in combination of two or more. Among the above inorganic fillers, fused silica is preferred from the viewpoint of reducing the coefficient of thermal expansion, alumina is preferred from the viewpoint of high thermal conductivity, and a spherical shape is preferred for the filler from the viewpoint of fluidity during molding and mold wear resistance.

[0105] The amount of inorganic fillers other than high dielectric constant fillers can be more preferably 3% to 30% by mass, and even more preferably 5% to 20% by mass, relative to the entire thermosetting resin composition, from the viewpoint of moldability, reduction of thermal expansion, and improvement of strength. Within the above range, excellent reduction of thermal expansion and moldability are achieved.

[0106] [Other hardening agents] The thermosetting resin composition of this embodiment may further contain curing agents other than the active ester curing agent (D). That is, in this embodiment, the curing agent does not include the active ester curing agent (D).

[0107] Examples of curing agents include amine compounds such as diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF3-amine complex, and guanidine derivatives; amide compounds such as dicyandiamide and polyamide resins synthesized from a linolenic acid dimer and ethylenediamine; acid anhydrides such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride; phenol novolac resins, cresol novolac resins, and aromatic hydrocarbon formaldehyde resins modified with phenol resins. Examples of polyhydric phenol compounds include lipids, dicyclopentadienephenol addition resins, phenol aralkyl resins, naphthol aralkyl resins, trimethylol methane resins, tetraphenyloleethane resins, naphthol novolac resins, naphthol-phenol co-condensed novolac resins, naphthol-cresol co-condensed novolac resins, biphenyl-modified phenol resins (polyhydric phenol compounds in which the phenol nucleus is linked by a bismethylene group), biphenyl-modified naphthol resins (polyhydric naphthol compounds in which the phenol nucleus is linked by a bismethylene group), and aminotriazine-modified phenol resins (polyhydric phenol compounds in which the phenol nucleus is linked by melamine or benzoguanamine, etc.), with phenol aralkyl resins being preferred.

[0108] When using other curing agents together with the active ester curing agent (D), the amount of the other curing agent is preferably 0.5% to 20% by mass, more preferably 1.0% to 15% by mass, and even more preferably 2.0% to 10% by mass, relative to the thermosetting resin. By using the curing agent in the above range, a thermosetting resin composition with excellent curability can be obtained.

[0109] [Other ingredients] In addition to the above components, the thermosetting resin composition of this embodiment may optionally contain various components such as mold release agents, colorants, dispersants, and stress reducers.

[0110] [Thermosetting resin composition] The thermosetting resin composition of this embodiment can be produced by uniformly mixing the above-mentioned components. A possible production method involves thoroughly mixing predetermined amounts of raw materials using a mixer, then melt-kneading them using a mixing roll, kneader, extruder, etc., followed by cooling and pulverization. The resulting thermosetting resin composition may, if necessary, be formed into tablets of a size and mass suitable for molding conditions.

[0111] The thermosetting resin composition of this embodiment has the following dielectric constant and dielectric loss tangent (tanδ) in the cured product obtained by heating at 200°C for 90 minutes. The dielectric loss tangent (tanδ) at 10 GHz can be set to 0.03 or less, preferably 0.02 or less, more preferably 0.01 or less, and particularly preferably 0.008 or less, using the cavity resonator method. The dielectric constant at 10 GHz can be set to 10 or higher, preferably 15 or higher, and more preferably 20 or higher, using the cavity resonator method.

[0112] The cured product obtained from the thermosetting resin composition of this embodiment exhibits excellent high dielectric constant and low dielectric loss tangent in the high-frequency band, enabling higher frequencies, and consequently shortening of circuits and miniaturization of communication equipment. It can be suitably used as a material for forming microstrip antennas, materials for forming dielectric waveguides, and materials for forming electromagnetic wave absorbers.

[0113] <Microstrip antenna> As shown in Figure 1, the microstrip antenna 10 of this embodiment comprises a dielectric substrate 12 formed by curing the above-mentioned resin composition, a radiating conductor plate (radiating element) 14 provided on one side of the dielectric substrate 12, and a ground conductor plate 16 provided on the other side of the dielectric substrate 12. At least a portion of the radiating conductor plate 12 is embedded in the dielectric substrate 12. The shape of the radiating conductor plate can be rectangular or circular. In this embodiment, an example using a rectangular radiating conductor plate 14 will be described.

[0114] The radiating conductor plate 14 includes one of the following: a metallic material, an alloy of a metallic material, a cured product of a metallic paste, or a conductive polymer. The metallic material includes copper, silver, palladium, gold, platinum, aluminum, chromium, nickel, cadmium lead, selenium, manganese, tin, vanadium, lithium, cobalt, and titanium. The alloy includes multiple metallic materials. The metallic paste includes a mixture of metallic material powder with an organic solvent and a binder. The binder includes epoxy resin, polyester resin, polyimide resin, polyamide-imide resin, and polyetherimide resin. The conductive polymer includes polythiophene-based polymers, polyacetylene-based polymers, polyaniline-based polymers, polypyrrole-based polymers, and the like.

[0115] As shown in Figure 1, the microstrip antenna 10 of this embodiment has a radiating conductor plate 14 with length L and width W, and resonates at a frequency where L is an integer multiple of half a wavelength. When a dielectric substrate 12 with a high dielectric constant is used, 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 with respect to the wavelength.

[0116] The ground conductor plate 16 is a thin plate made of a highly conductive metal such as copper, silver, or gold. Its thickness should be sufficiently thin relative to the center operating frequency of the antenna device, and should be approximately 1 / 50th to 1 / 1000th of a wavelength of the center operating frequency.

[0117] Methods for feeding microstrip antennas include direct feeding methods such as rear-coaxial feeding and coplanar feeding, and electromagnetically coupled feeding methods such as slot-coupled feeding and proximity-coupled feeding. Rear coaxial power supply allows power to be supplied from the back of the antenna to the radiating conductor plate 14 using a coaxial line or connector that penetrates the ground conductor plate 16 and the dielectric substrate 12. Coplanar power supply allows power to be supplied to the radiating conductor plate 14 via a microstrip line (not shown) arranged on the same plane as the radiating conductor plate 14.

[0118] In slot-coupled power supply, 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 electromagnetic coupling the radiating conductor plate 14 and the microstrip line through slots made in the ground conductor plate 16.

[0119] In close-range coupled power supply, the dielectric substrate 12 has a laminated structure, with a dielectric substrate on which a radiating conductor plate 14 is formed and a dielectric substrate on which the strip conductors of the microstrip line and the ground conductor plate 16 are arranged being laminated. The strip conductors of the microstrip line are extended to the lower part 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.

[0120] Figures 2(a) and 2(b) show other configurations of microstrip antennas. Note that configurations identical to those in Figure 1 are given the same numbers, and explanations are omitted where appropriate. As shown in Figure 2(a), the microstrip antenna 20 comprises a dielectric substrate 22, a radiating conductor plate 14 provided on one side of the dielectric substrate 22, a ground conductor plate 16 provided on the other side of the dielectric substrate 22, and a high-dielectric substrate (high-dielectric) 24 positioned opposite the radiating conductor plate 14. The dielectric substrate 22, the radiating conductor plate 14, and the high-dielectric substrate 24 can be configured to be spaced a predetermined distance apart via a spacer 26.

[0121] The dielectric substrate 22 is made from a substrate with a low dielectric constant, such as a Teflon substrate. The high-dielectric substrate 24 is composed 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 an empty space, or it may be filled with a dielectric material. Furthermore, as shown in the microstrip antenna 20' in Figure 2(b), a structure can also be adopted in which a high-dielectric substrate 24 is in contact with the upper surface of the radiating conductor plate 14.

[0122] <Dielectric Waveguide> In this embodiment, the dielectric waveguide comprises a dielectric obtained by curing the resin composition of this embodiment, and a conductive film covering the surface of the dielectric. The dielectric waveguide transmits electromagnetic waves by confining them within the dielectric (dielectric medium). The conductive film can be made of a metal such as copper, or an oxide high-temperature superconductor, etc.

[0123] <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. This electromagnetic wave absorber can be used as a λ / 4 type radio wave absorber with high radio wave absorption performance.

[0124] Examples of support materials include resin substrates. The support material can protect the resistive coating and improve the durability of the radio wave absorber. Examples of resistive coatings include indium tin oxide and molybdenum-containing resistive coatings. The dielectric layer is formed by curing the resin composition of this embodiment. Its thickness is approximately 10 μm to 2000 μm. A reflective layer can function as a reflection layer for radio waves, and examples include metal films.

[0125] Although embodiments of the present invention have been described above, these are merely examples, and various other configurations can be adopted as long as they do not impair the effects of the present invention. [Examples]

[0126] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0127] (Comparative Example 1, Examples 1-3) The following raw materials were mixed at room temperature using a mixer in the proportions shown in Table 1, and then roll-kneaded at 70-100°C. Next, the resulting mixture was cooled and then pulverized to obtain a granular resin composition. Finally, tablet-shaped resin compositions were obtained by high-pressure tablet molding.

[0128] (High dielectric constant filler) • High dielectric constant filler: Calcium titanate (average particle size 7.5 μm)

[0129] (Coupling agent) • Coupling agent 1: N-phenyl-3-aminopropyltrimethoxysilane (CF4083, manufactured by Toray Dow Corning) • Coupling agent 2: Trimethoxyphenylsilane • Coupling agent 3: Trimethoxysilane • Coupling agent 4: Trimethoxymethylsilane

[0130] (thermosetting resin) • Epoxy resin: Biphenylene skeleton-containing phenol aralkyl type epoxy resin (NC3000, manufactured by Nippon Kayaku Co., Ltd.)

[0131] (catalyst) • Catalyst 1: Tetraphenylphosphonium-4,4'-sulfonyldiphenolate • Catalyst 2: Tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenylsilicate

[0132] (Hardening agent) • Hardener: Active ester hardener prepared by the following preparation method (Method for preparing activated ester curing agents) In a flask equipped with a thermometer, dropping funnel, condenser, fractionation column, and stirrer, 203.0 g of 1,3-benzenedicarboxylic acid dichloride (2.0 moles of acid chloride groups) and 1338 g of toluene were charged, and the mixture was dissolved under reduced pressure and nitrogen purging. Next, 96.5 g (0.67 moles) of α-naphthol and 219.5 g of dicyclopentadienephenol resin (1.33 moles of phenolic hydroxyl groups) were charged, and the mixture was dissolved under reduced pressure and nitrogen purging. Subsequently, while purging with nitrogen gas, the temperature in the system was controlled to below 60°C, and 400 g of 20% sodium hydroxide aqueous solution was added dropwise over 3 hours. Stirring was then continued under these conditions for 1.0 hour. After the reaction was complete, the mixture was allowed to stand and separated, and the aqueous layer was removed. Furthermore, water was added to the toluene phase containing the dissolved reactants, and the mixture was stirred for approximately 15 minutes, then allowed to stand and separated, and the aqueous layer was removed. This procedure was repeated until the pH of the aqueous layer reached 7. Then, water was removed by decanter dehydration to obtain an activated ester resin in a toluene solution with 65% non-volatile content. Upon examining the structure of the obtained activated ester resin, it was found that in the above formula (1-3), R 1 and R 3 The structure had 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 in the range of 0.5 to 1.0, calculated from the reaction equivalence ratio. The obtained active ester resin 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.

[0133] [ka]

[0134] (Release agent) • Release agent: Carnauba wax (TOWAX-132, manufactured by Toagosei Co., Ltd.)

[0135] (Coloring agent) • Mixture of titanium nitride and titanium oxide: 50% titanium nitride by mass, 50% titanium oxide by mass, average particle size D 50 : 0.1 μm

[0136] (Additives) • Silicone: Dimethylsiloxane-diglycidine ether copolymer (M69B, manufactured by Sumitomo Bakelite Co., Ltd.)

[0137] (Stress-reducing agent) • Low-stress agent: Carboxylate-terminated butadiene acrylic rubber (CTBN1008SP, manufactured by Ube Industries, Ltd.)

[0138] (Inorganic fillers) • Inorganic filler 1: Molten spherical silica 1 (average particle size 0.6 μm, manufactured by Admatex) • Inorganic filler 2: Molten spherical silica 2 (average particle size 1.6 μm, manufactured by Admatex)

[0139] (Evaluation of dielectric constant and dielectric loss tangent using the cavity resonator method) First, test specimens were obtained using a resin composition. Specifically, the resin compositions prepared in the examples and comparative examples were applied to a Si substrate, pre-baked at 120°C for 4 minutes, and a resin film with a coating thickness of 12 μm was formed. This was heated in an oven at 200°C for 90 minutes under a nitrogen atmosphere, and then treated with hydrofluoric acid (immersed in a 2% by mass hydrofluoric acid aqueous solution). After removing the substrate from the hydrofluoric acid, the cured film was peeled off the Si substrate and used as a test specimen. The measurement equipment used consisted of a network analyzer HP8510C, a synthesized sweeper HP83651A, and a test set HP8517B (all manufactured by Agilent Technologies). These devices were set up in conjunction with a cylindrical cavity resonator (inner diameter φ42 mm, height 30 mm). The resonance frequency, 3 dB bandwidth, transmission power ratio, etc. were measured at a frequency of 10 GHz with a test piece inserted into the resonator and without insertion. Then, by analytically calculating these measurement results with software, the dielectric properties of the dielectric constant (Dk) and dielectric tangent (Df) were determined. The measurement mode was TE 011 mode.

[0140] (Glass transition temperature, coefficient of linear expansion) For each of the examples and comparative examples, the glass transition temperature (Tg) and coefficient of linear expansion (CTE1, CTE2) of the cured product of the obtained resin composition were measured as follows. First, a sealing resin composition was injection-molded using a low-pressure transfer molding machine ("KTS-15" manufactured by Kotaki Seiki Co., Ltd.) at a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 120 seconds to obtain test pieces of 10 mm × 4 mm × 4 mm. Next, after post-curing the obtained test pieces at 175°C for 4 hours, measurement was performed using a thermomechanical analyzer (TMA100 manufactured by Seiko Denshi Kogyo Co., Ltd.) under the conditions of a measurement temperature range of 0°C to 320°C and a heating rate of 5°C / min. From this measurement result, the glass transition temperature (Tg), the coefficient of linear expansion (CTE1) below the glass transition temperature, and the coefficient of linear expansion (CTE2) above the glass transition temperature were calculated.

[0141] (Evaluation of mechanical strength (flexural strength / flexural modulus)) The resin compositions of the examples and comparative examples were injection-molded into a mold using a low-pressure transfer molding machine ("KTS-30" manufactured by Kotaki Seiki Co., Ltd.) under the conditions of a mold temperature of 130°C, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. As a result, molded products with a width of 10 mm, a thickness of 4 mm, and a length of 80 mm were obtained. Next, the obtained molded products were post-cured at 175°C for 4 hours. As a result, test pieces for evaluating mechanical strength were produced. Then, the flexural strength (N / mm 2 ) and flexural modulus (N / mm 2 ) at room temperature (25°C) or 260°C of the test pieces were measured in accordance with JIS K 6911 at a head speed of 5 mm / min.

[0142] (Water absorption) Using a low-pressure transfer molding machine (KTS-30, manufactured by Kotaki Seiki Co., Ltd.), a thermosetting resin composition was injected and molded under the conditions of a mold temperature of 175°C, injection pressure of 7.4 MPa, and curing time of 120 seconds to produce test specimens with a diameter of 50 mm and a thickness of 3 mm. These specimens were cured at 175°C for 4 hours. Subsequently, the obtained test specimens were treated in boiling water for 24 hours, and the change in weight before and after the humidification treatment was measured to determine the moisture absorption rate. The unit is % (mass%).

[0143] [Table 1]

[0144] As shown in Table 1, the compositions of the examples according to the present invention, which used a coupling agent without a polar group at one end, yielded cured products (dielectric substrates) that were superior in low dielectric loss tangent and high dielectric constant compared to the comparative examples compositions using a coupling agent with a polar group at one end. In other words, the dielectric substrates obtained from the thermosetting resin compositions of the examples exhibited an excellent balance between high dielectric constant and low dielectric loss tangent. It was inferred that a microstrip antenna equipped with a dielectric substrate cured from this resin composition would enable higher frequencies, and consequently, shorter circuits and miniaturized communication equipment. Furthermore, it was inferred that the desired effects could also be obtained in dielectric waveguides and electromagnetic wave absorbers equipped with a dielectric (layer) cured from this resin composition. [Explanation of symbols]

[0145] 10 Microstrip Antennas 12 Dielectric substrate 14 Radiating Conductor Plate 16 Ground conductor plate 20, 20' Microstrip Antenna 22 Dielectric substrate 24 High-dielectric substrates 26 Spacers a Cavity

Claims

1. (A) Thermosetting resin and (B) High dielectric constant filler, (C) A coupling agent represented by the following general formula (1), Includes, A thermosetting resin composition wherein the high dielectric constant filler (B) comprises at least one selected from calcium titanate, strontium titanate, barium titanate, magnesium titanate, and titanium oxide. 【Chemistry 1】 (In general formula (1), m is 2 or 3, R １ R represents a methoxy group or an ethoxy group, and there are multiple R groups. １ These may be the same or different. Q represents a hydrogen atom, a phenyl group, an alkyl group having 1 to 12 carbon atoms, or a cycloalkyl group having 3 to 12 carbon atoms. Multiple Qs may be the same or different.

2. The thermosetting resin composition according to claim 1, wherein the thermosetting resin (A) comprises an epoxy resin.

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

4. The thermosetting resin composition according to claim 1, further comprising an active ester curing agent (D).

5. The thermosetting resin composition according to claim 4, wherein the active ester curing agent (D) comprises at least one selected from 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 phenol novolac, and an active ester curing agent containing a benzoylated phenol novolac.

6. The thermosetting resin composition according to claim 5, wherein the activated ester curing agent (D) has a structure represented by the following general formula (2). 【Chemistry 2】 (In general formula (2), A is a substituted or unsubstituted arylene group linked via an aliphatic cyclic hydrocarbon group, and Ar' is a substituted or unsubstituted aryl group, B is a structure represented by the following general formula (B), 【Transformation 3】 (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, 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. n is an integer from 0 to 4.) k is the average value of the repeating units, and is in the range of 0.25 to 3.

5.

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

8. A thermosetting resin composition according to any one of claims 1 to 7, used as a material for forming a microstrip antenna.

9. A thermosetting resin composition according to any one of claims 1 to 7, used as a material for forming a dielectric waveguide.

10. A thermosetting resin composition according to any one of claims 1 to 7, used as a material for forming an electromagnetic wave absorber.

11. A dielectric substrate made of a cured product of the thermosetting resin composition according to any one of claims 1 to 7.

12. A dielectric substrate according to claim 11, A radiating conductor plate provided on one side of the dielectric substrate, A ground conductor plate provided on the other side of the dielectric substrate, A microstrip antenna equipped with the following features.

13. Dielectric substrate and A radiating conductor plate provided on one side of the dielectric substrate, A ground conductor plate provided on the other side of the dielectric substrate, A high dielectric material is arranged opposite the aforementioned radiating conductor plate, A microstrip antenna comprising, A microstrip antenna in which the high dielectric material is made of the dielectric substrate described in claim 11.

Images