JP2023179419A - Heat curable resin composition, high-frequency device, dielectric substrate, and micro strip antenna - Google Patents

Abstract

To provide a heat curable resin composition excellent in void suppression and packing properties in forming a component, shape retention nature, toughness, a high dielectric constant, and a low dielectric tangent in the component, and to provide a high-frequency device using the heat curable resin composition.SOLUTION: A heat curable resin composition contains an epoxy resin (A), a hardening agent (B), and a filler of a high permittivity constant (C). The filler of a high permittivity constant (C) contains calcium titanate particles of 50 mass% or more or strontium titanate particles of 60 mass% or more relative to 100 mass% of a solid part of the heat curable resin composition. The epoxy rein (A) contains a biphenylaralkyl type epoxy resin and/or a biphenyl type epoxy resin. The hardening agent (B) contains an active ester compound (B1) and/or a phenol-based hardening agent (B2).SELECTED DRAWING: None

Description

The present invention relates to a thermosetting resin composition, a high frequency device, a dielectric substrate, and a microstrip antenna.

In recent years, wireless communication has become faster, and there is a demand for higher performance and smaller size of the communication equipment used. Furthermore, in recent years, the capacity of wireless communication has increased rapidly, and as a result, the frequencies used for transmission signals are rapidly becoming wider and higher in frequency. For this reason, the frequency band used by communication equipment cannot be supported by the conventional microwave band alone, and is being expanded to include the millimeter wave band. Against this background, there is a strong demand for higher performance antennas installed in communication equipment.

Communication equipment can be further miniaturized if the dielectric constant of the antenna material (dielectric substrate) built into the communication equipment increases. Furthermore, when the dielectric loss tangent of the dielectric substrate becomes smaller, the loss becomes lower, 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 is possible to achieve higher frequencies, thereby shortening the circuit length and downsizing the communication equipment.

Patent Document 1 describes a high dielectric constant resin composition containing an epoxy resin and a high dielectric constant inorganic filler such as strontium titanate (Claim 1, Table 2, etc.).

Patent Document 2 describes a laminate of a dielectric substrate made of a composite material containing a fluororesin and a glass cloth, and an antenna whose surface in contact with the fluororesin has a two-dimensional roughness Ra of less than 0.2 μm. An antenna having a substrate is disclosed. This document describes the dielectric constant and dielectric loss tangent of a circuit board measured at 1 GHz.

Patent Document 3 discloses a resin composition that includes a siloxane-modified polyamideimide resin, a high dielectric constant filler, and an epoxy resin, and has a cured product having a dielectric constant of 15 or more at 25° C. and 1 MHz. Examples of this document describe an example in which barium titanate is used as the high dielectric constant filler.

Patent Document 4 discloses a resin composition containing an epoxy resin, a dielectric powder, a nonionic surfactant, and an active ester curing agent. This document states that this resin composition can be used as a high dielectric constant insulating material for electronic components used in a high frequency region and a high dielectric constant insulating material for fingerprint sensors. The example of this document describes an example in which barium titanate is used as the dielectric powder.

Patent Document 5 discloses an epoxy resin, a curing agent, and an inorganic filler containing predetermined amounts of calcium titanate particles and strontium titanate particles, the inorganic filler consisting of silica particles and alumina particles. Disclosed is a molding resin composition which further contains at least one member selected from the group consisting of:

Japanese Patent Application Publication No. 2008-106106 JP 2018-41998 Publication Japanese Patent Application Publication No. 2004-315653 JP 2020-105523 Publication Patent No. 6870778

However, the conventional techniques described in Patent Documents 1 to 4 have room for improvement in the following points.
It has been found that there is room for improvement in the resin composition described in Patent Document 1 mentioned above in terms of void suppression and filling properties during molding of a member, shape retention of the member, and toughness. This should be the first issue.
Furthermore, the dielectric substrates described in Patent Documents 2 to 5 have problems with high dielectric constants and low dielectric loss tangents, and these problems are particularly noticeable in high frequency bands. This is the second issue.

The present inventors highly filled a thermosetting resin composition with calcium titanate particles or strontium titanate particles as a high dielectric constant filler, and then employed a combination of a predetermined epoxy resin and a predetermined curing agent. The inventors have discovered that the first problem can be solved by adjusting the bending elastic modulus and rectangular pressure at 260° C. within appropriate ranges, and have completed the first invention.
That is, the first invention can be shown below.

According to the first invention,
(A) epoxy resin,
A thermosetting resin composition comprising (B) a curing agent and (C) a high dielectric constant filler,
The high dielectric constant filler (C) contains 50% by mass or more of calcium titanate particles or 60% by mass or more of strontium titanate particles based on 100% by mass of the solid content of the thermosetting resin composition,
The epoxy resin (A) contains a biphenylaralkyl epoxy resin and/or a biphenyl epoxy resin,
The curing agent (B) contains an active ester compound (B1) and/or a phenolic curing agent (B2),
The active ester compound (B1) is an active ester compound containing a dicyclopentadiene type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester containing a benzoylated product of phenol novolac. Contains at least one selected from compounds,
The phenolic curing agent (B2) contains a biphenylaralkyl phenol resin and/or a phenol novolak resin,
The bending elastic modulus at 260° C., measured according to Procedure 1 below, is 50 N/mm ² or more and 190 N/mm ² or less,
The rectangular pressure measured according to procedure 2 below is 0.2 MPa or more and 8.8 MPa or less,
A thermosetting resin composition is provided.
(Step 1)
The thermosetting resin composition was injection-molded into a mold using a low-pressure transfer molding machine under the conditions of a mold temperature of 130°C, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. A molded product with a length of 80 mm is obtained.
The obtained molded product is post-cured at 175° C. for 4 hours to prepare a test piece.
The flexural modulus (N/mm ² ) of the test piece at 260° C. is measured in accordance with JIS K 6911.
(Step 2)
Using a low-pressure transfer molding machine, the thermosetting resin composition was poured into a rectangular channel with ^a width of 13 mm, a thickness of 1 mm, and a length of 175 mm under conditions of a mold temperature of 175° C. and an injection speed of 177 mm 3 /sec. Injected. At this time, a pressure sensor embedded at a position 25 mm from the upstream end of the flow path measures the change in pressure over time, and the lowest pressure (MPa) during the flow of the thermosetting resin composition is measured, and this is Press.

Further, according to the first invention,
A high frequency device is provided that includes a cured product of the above thermosetting resin composition.

The present inventors also discovered that a thermosetting resin composition containing an epoxy resin, a curing agent, and a high dielectric constant filler contains a specific epoxy resin and an active ester curing agent as a curing agent in combination. The inventors discovered that the second problem mentioned above could be solved by doing so, and completed the second invention.
That is, the second invention can be shown below.

According to the second invention,
(A) an epoxy resin;
(B) a curing agent;
(C) a high dielectric constant filler;
A thermosetting resin composition comprising,
The epoxy resin (A) is selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, naphthalene epoxy resin, dicyclopentadiene epoxy resin, glycidylamine epoxy resin, and naphthol aralkyl epoxy resin. containing at least one species of
The curing agent (B) contains an active ester curing agent (B1) and/or a phenolic curing agent (B2),
The high dielectric constant filler (C) is calcium titanate, strontium titanate, magnesium titanate, magnesium zirconate, strontium zirconate, bismuth titanate, zirconium titanate, zinc titanate, barium zirconate, zircon titanate. Provided is a thermosetting resin composition containing at least one selected from calcium acid, lead zirconate titanate, barium magnesium niobate, and calcium zirconate.

According to the second invention,
A dielectric substrate obtained by curing the thermosetting resin composition is provided.

According to the first or second invention,
the 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 microstrip antenna is provided.

According to the first or second invention,
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 to the radiation conductor plate;
A microstrip antenna comprising:
A microstrip antenna is provided, wherein the high dielectric material is constituted by the dielectric substrate.

According to the first invention, there is provided a thermosetting resin composition that is excellent in void suppression and filling properties during molding of a member, as well as shape retention, toughness, high dielectric constant, and low dielectric loss tangent in the member, and a thermosetting resin composition using the same. We can provide high frequency devices with
Further, according to the second invention, there is provided a thermosetting resin composition capable of obtaining a dielectric substrate excellent in high dielectric constant and low dielectric loss tangent, a dielectric substrate made of the resin composition, and the dielectric substrate. A microstrip antenna can be provided.

FIG. 2 is a top perspective view showing the microstrip antenna of this embodiment. FIG. 3 is a cross-sectional view showing another aspect of the microstrip antenna of this embodiment.

Hereinafter, the first invention (claims 1 to 14 and 23 to 25 as filed) will be explained based on the first embodiment with reference to the drawings, and the second invention (claims 15 to 22 as filed) will be explained based on the first embodiment with reference to the drawings. , 23 to 25) will be explained based on the second embodiment with reference to the drawings.
Note that in all the drawings, similar components are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate. Further, for example, "1 to 10" represents "1 or more" to "10 or less" unless otherwise specified.

<First invention>
An overview of the thermosetting resin composition of the first embodiment will be explained.

The thermosetting resin composition of the present embodiment includes an epoxy resin (A), a curing agent (B), and a high dielectric constant filler (C), and the high dielectric constant filler (C) is a component of the thermosetting resin composition. Containing 50% by mass or more of calcium titanate particles or 60% by mass or more of strontium titanate particles in 100% by mass of the solid content of the product,
The epoxy resin (A) contains a biphenylaralkyl epoxy resin and/or a biphenyl epoxy resin, the curing agent (B) contains an active ester compound (B1) and/or a phenolic curing agent (B2), and the curing agent (B) contains an active ester compound (B1) and/or a phenolic curing agent (B2). At least the compound is selected from an active ester compound containing a dicyclopentadiene type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester compound containing a benzoylated product of phenol novolac. The phenolic curing agent contains a biphenylaralkyl type phenol resin and/or a phenol novolac resin.
Such a thermosetting resin composition has a flexural modulus of elasticity at 260°C of 50 N/mm ² or more and 190 N/mm ^{2 or} less, as measured according to Procedure 1 below, and measured according to Procedure 2 below. The rectangular pressure is configured to be 0.2 MPa or more and 8.8 MPa or less.

In response to the current demand for high dielectric constant and low dielectric loss tangent, it has become necessary to increase the content of a specific high dielectric constant filler.
However, depending on the type and content of the high dielectric constant filler, the moldability of the thermosetting resin composition may be reduced. In order to deal with such molding defects, the present inventors investigated the flow characteristics of thermosetting resin compositions.
According to the findings of the present inventors, the index of rectangular pressure can stably evaluate the flow characteristics of a thermosetting resin composition highly filled with a high dielectric constant filler. Therefore, by controlling the viscosity of the thermosetting resin to be equal to or less than the above upper limit, a thermosetting resin composition with excellent moldability can be realized.

Moreover, the temperature of the operating environment is currently increasing due to design factors such as higher frequencies, higher outputs of power semiconductors, and lower profile devices. In order to cope with such an increase in the temperature of the operating environment, the inventors investigated the thermal characteristics of a cured product of a thermosetting resin composition.
According to the findings of the present inventors, the index of flexural modulus at 260° C. can stably evaluate the difficulty of deforming a cured product of a thermosetting resin composition when heated.
Therefore, by setting the 260° C. flexural modulus to the above lower limit value or more, it can be expected that deterioration of dielectric properties due to thermal deterioration of the member will be suppressed.

In this embodiment, for example, by appropriately selecting the type and amount of each component contained in the thermosetting resin composition, the method for preparing the thermosetting resin composition, etc., It is possible to control the elastic modulus, 25° C. bending modulus, 260° C. bending strength, 25° C. bending strength, water absorption, thermal conductivity, die shear strength, glass transition temperature, and coefficient of linear expansion. Among these, for example, 50% by mass or more of calcium titanate particles or 60% by mass or more of strontium titanate particles are used as a high dielectric constant filler, and biphenylaralkyl-type epoxy resin and/or biphenyl-type epoxy are used as the epoxy resin. The active ester compound includes an active ester compound containing a dicyclopentadiene diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated phenol novolac, and a benzoylated phenol novolac. Using at least one selected from active ester compounds and/or a biphenylaralkyl phenol resin and/or a phenol novolac resin as a phenolic curing agent, appropriately adjusting the content of the inorganic filler, etc. However, the above rectangular pressure, 260°C flexural modulus, 25°C flexural modulus, 260°C flexural strength, 25°C flexural strength, water absorption, thermal conductivity, die shear strength, glass transition temperature, and coefficient of linear expansion can be adjusted to the desired values. It is listed as an element for creating a numerical range.

The lower limit of the bending modulus at 260° C. is 50 N/mm ² or more, preferably 60 N/mm ² or more, more preferably 70 N/mm ^{2 or} more. Thereby, the shape retention of the member can be improved.
The upper limit of the flexural modulus at 260° C. is 190 N/mm ² or less, preferably 180 N/mm ² or less, more preferably 150 N/mm ² or less. Thereby, the toughness of the member can be improved.

The lower limit of the rectangular pressure is 0.2 MPa or more, preferably 0.25 MPa or more, and more preferably 0.3 MPa or more. This makes it possible to suppress the generation of voids during molding of the member.
The upper limit of the rectangular pressure is 8.8 MPa or less, preferably 8.7 MPa or less, more preferably 8.6 MPa or less. Thereby, the filling properties during molding of the member can be improved.

The lower limit of the flexural modulus at 25° C. is, for example, 9000 N/mm ² or more, preferably 10000 N/mm ² or more, more preferably 12000 N/mm ² or more. Thereby, the shape retention of the member at room temperature can be improved.
The upper limit of the flexural modulus at 25° C. is, for example, 28,000 N/mm ² or less, preferably 27,000 N/mm ² or less, more preferably 26,000 N/mm ² or less. Thereby, the toughness of the member at room temperature can be improved.

The lower limit of the bending strength at 25° C. is, for example, 40 N/mm ² or more, preferably 45 N/mm ² or more, more preferably 50 N/mm ² or more. Thereby, the shape retention of the member at room temperature can be improved.
The upper limit of the bending strength at 25° C. is, for example, 200 N/mm ² or less, preferably 180 N/mm ² or less, more preferably 150 N/mm ² or less. Thereby, the toughness of the member at room temperature can be improved.

The lower limit of the bending strength at 260° C. is, for example, 0.1 N/mm ² or more, preferably 0.5 N/mm ² or more, more preferably 1 N/mm ² or more. Thereby, the shape retention of the member under high temperature environment can be improved.
The upper limit of the bending strength at 260° C. is, for example, 10 N/mm ² or less, preferably 7 N/mm ² or less, more preferably 5 N/mm ² or less. Thereby, the toughness of the member can be improved in a high-temperature environment.

The lower limit of the water absorption rate is not particularly limited, but may be 0.01% or more, or 0.05% or more.
The upper limit of the water absorption rate is, for example, 0.8% or less, preferably 0.7% or less, and more preferably 0.6% or less. This makes it possible to achieve low water absorption of the member.

The lower limit of the thermal conductivity is, for example, 1.0 W/mK or more, preferably 1.5 W/mK or more, and more preferably 2.0 W/mK or more. Thereby, the heat transfer characteristics of the member can be improved.
The upper limit of the thermal conductivity is not particularly limited, but may be 5.0 W/mK or less, preferably 4.0 W/mK or less.

The lower limit of the die shear strength against copper is, for example, 5 N/mm ² or more, preferably 6 N/mm ² or more, more preferably 7 N/mm ^{2 or} more. Thereby, the adhesiveness with the metal member can be improved.
The upper limit of the die shear strength for copper is not particularly limited, but may be 50 N/mm ² or less, 40 N/mm ² or less, or 30 N/mm ² or less.

The lower limit of the glass transition temperature is, for example, 90°C or higher, preferably 95°C or higher, and more preferably 100°C or higher. Thereby, the heat resistance of the member can be improved.
The upper limit of the glass transition temperature is not particularly limited, but may be 200°C or lower, or 190°C or lower.

In the cured product of the thermosetting resin composition, the coefficient of linear expansion in the range below the glass transition temperature is defined as CTE1, and the coefficient of linear expansion in the range above the glass transition temperature and below 320°C is defined as CTE2.

The lower limit of CTE1 is not particularly limited, but may be 5 ppm/°C or more, or 6 ppm/°C or more.
The upper limit of CTE1 is, for example, 30 ppm/°C or less, preferably 28 ppm/°C or less, more preferably 25 ppm or less. Thereby, dimensional changes of the member below Tg can be suppressed.

The lower limit of CTE2 is not particularly limited, but may be 10 ppm/°C or more, preferably 30 ppm/°C or more.
The upper limit of CTE2 is, for example, 100 ppm/°C or less, preferably 90 ppm/°C or less, more preferably 80 ppm/°C or less. This makes it possible to suppress dimensional changes in the member during heating.

(Measurement procedure 1 of bending elastic modulus and bending strength)
The thermosetting resin composition was injection-molded into a mold using a low-pressure transfer molding machine under the conditions of a mold temperature of 130°C, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. A molded article of 80 mm is obtained.
The obtained molded product is post-cured at 175° C. for 4 hours to prepare a test piece.
In accordance with JIS K 6911, the flexural modulus (N/mm 2 ) and flexural strength (N/mm ² ) of the test piece were measured at room temperature (25°C) and 260°C at a head speed of 5 mm/min, ^respectively . Measure.

(Measurement procedure of rectangular pressure 2)
Using a low-pressure transfer molding machine, the thermosetting resin composition was injected into a rectangular channel with ^a width of 13 mm, a thickness of 1 mm, and a length of 175 mm under conditions of a mold temperature of 175° C. and an injection speed of 177 mm 3 /sec. did. At this time, a pressure sensor embedded at a position 25 mm from the upstream end of the flow path measures the change in pressure over time, and the lowest pressure (MPa) during flow of the thermosetting resin composition is measured, and this is calculated as the rectangular pressure. .

(Measurement procedure for die shear strength against copper)
Using a low-pressure transfer molding machine, the thermosetting resin composition was molded under the conditions of a mold temperature of 175°C, an injection pressure of 10 MPa, and a curing time of 180 seconds, and one 10 mm ² test piece was placed on a copper lead frame. Form 4 pieces per level.
Subsequently, the die shear strength between the test piece and the copper lead frame is measured at room temperature using an automatic die shear measuring device. The die shear strength of four test pieces is adopted.

Each component of the thermosetting resin composition of this embodiment will be described in detail below.

.
[Thermosetting resin]
The thermosetting resin composition of this embodiment contains an epoxy resin (A) as a thermosetting resin.

As the epoxy resin (A), monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule can be used, and the molecular weight and molecular structure thereof are not limited.

The epoxy resin (A) contains at least a biphenylaralkyl epoxy resin and/or a biphenyl epoxy resin (excluding the biphenylaralkyl epoxy resin).

The epoxy resin (A) may contain a biphenylaralkyl epoxy resin and an epoxy resin other than the biphenyl epoxy resin.
Examples of the biphenylaralkyl epoxy resin include phenolaralkyl epoxy resins having a biphenylene skeleton, naphthol aralkyl epoxy resins having a biphenylene skeleton, and the like.

Other epoxy resins include, for example, 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 resin; phenol novolac type epoxy resin, cresol novolac type epoxy resin Novolac type epoxy resins such as; polyfunctional epoxy resins such as trisphenol type epoxy resins such as triphenolmethane type epoxy resins and alkyl-modified triphenolmethane type epoxy resins; phenol aralkyl type epoxy resins having a phenylene skeleton, phenylene Phenol aralkyl type epoxy resins such as naphthol aralkyl type epoxy resins having a skeleton; epoxy resins containing a biphenylene skeleton; dihydroxynaphthalene type epoxy resins, naphthol type epoxy resins such as epoxy resins obtained by glycidyl etherification of dihydroxynaphthalene dimers ; 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. These may be used alone or in combination of two or more.

The thermosetting resin composition may also contain thermosetting resins other than epoxy resin.
The other thermosetting resin may include one or more selected from cyanate resins and maleimide resins.

The content of the epoxy resin (A) is, for example, 5% by mass or more, preferably 7% by mass or more in 100% by mass of the thermosetting resin composition. Further, the content of the epoxy resin (A) is, for example, 20% by mass or less, preferably 15% by mass or less, based on 100% by mass of the thermosetting resin composition.

[High dielectric constant filler (C)]
The thermosetting resin composition contains a high dielectric constant filler (C).
The high dielectric constant filler (C) contains calcium titanate particles and/or strontium titanate particles. Thereby, the dielectric loss tangent in the high frequency band can be further reduced.

The thermosetting resin composition may contain other high dielectric constant fillers other than calcium titanate particles and strontium titanate particles.
Other high dielectric constant fillers include magnesium titanate, magnesium zirconate, strontium zirconate, bismuth titanate, zirconium titanate, zinc titanate, barium zirconate, calcium zirconate titanate, lead zirconate titanate, and niobium titanate. Examples include barium magnesium acid, calcium zirconate, and the like. One or more types selected from these can be used.

In the volume frequency particle size distribution of the high dielectric constant filler (C) measured by laser diffraction scattering method, the particle diameter at which the cumulative value is 10% is D ₁₀ , the particle diameter at which the cumulative value is 50% is D ₅₀ , and cumulative The particle diameter at which the value becomes 90% is defined as _D90 .

D ₁₀ , D ₅₀ and D ₉₀ are, for example, 0.25≦(D ₉₀ -D ₁₀ )/D ₅₀ ≦55, preferably 0.5≦(D ₉₀ -D ₁₀ )/D ₅₀ ≦50, more preferably is configured to satisfy 1.0≦(D ₉₀ −D ₁₀ )/D ₅₀ ≦40.

D ₅₀ is, for example, preferably 0.1 μm or more and 50 μm or less, more preferably 0.3 μm or more and 20 μm or less, and still more preferably 0.5 μm or more and 10 μm or less.

The shape of the high dielectric constant filler (C) is granular, amorphous, flake, etc., and high dielectric constant filler (C) having these shapes can be used in any ratio.

The lower limit of the content of calcium titanate particles is 50% by mass or more, preferably 55% by mass or more, and more preferably 60% by mass or more in 100% by mass of the thermosetting resin composition. Thereby, the dielectric loss tangent in the high frequency band can be further reduced.
The lower limit of the strontium titanate particles is 60% by mass or more, preferably 65% by mass or more, and more preferably 70% by mass or more in 100% by mass of the thermosetting resin composition. Thereby, the dielectric loss tangent in the high frequency band can be further reduced.
The upper limit of the calcium titanate particles and/or the strontium titanate particles is, for example, 90% by mass or less, preferably 85% by mass or less, more preferably 80% by mass or less in 100% by mass of the thermosetting resin composition. Thereby, the manufacturing stability of the molded product can be improved.

The thermosetting resin composition contains a curing agent (B).
The curing agent includes an active ester compound (B1) and/or a phenolic curing agent (B2). Preferably, the curing agent includes an active ester compound (B1) and a phenolic curing agent (B2).

[Active ester compound (B1)]
The active ester compound (active ester curing agent) (B1) functions as a curing agent for thermosetting resins such as epoxy resins.
The active ester compound (B1) is an active ester compound containing a dicyclopentadiene type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester compound containing a benzoylated product of phenol novolak. One or more selected from the group consisting of:
Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene type diphenol structure are more preferable. "Dicyclopentadiene type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

In this embodiment, the active ester compound (B1) can be, for example, a resin having a structure represented by the following general formula (1).

In the above general formula (1),
A is a substituted or unsubstituted arylene group connected 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),
k is the average value of repeating units and ranges from 0.25 to 3.5.

In the above general formula (B),
Ar is a substituted or unsubstituted arylene group. Examples of the substituents 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, an aralkyl group, and the like.
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, or a substituted or unsubstituted divalent aromatic hydrocarbon group, ether bond, carbonyl group, carbonyloxy group, sulfide group, or sulfone group. Examples of the substituent of the above group include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, an aralkyl group, and the like.
Preferred examples of Y include a single bond, a methylene group, -CH(CH ₃ ) ₂ -, an ether bond, an optionally substituted cycloalkylene group, and an optionally substituted 9,9-fluorenylene group.
n is an integer from 0 to 4, preferably 0 or 1.
Specifically, B is a structure represented by the following general formula (B1) or the following general formula (B2).

In the general formula (B1) and the general formula (B2), Ar and Y have the same meanings as in the general formula (B).

Since the thermosetting resin composition of this embodiment contains a specific active ester compound, the obtained cured product can have excellent dielectric properties and is excellent in low dielectric loss tangent.

The active ester compound (B1) 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 (A) and the active ester compound (B1), the active ester group of the active ester compound (B1) reacts with the epoxy group of the epoxy resin (A) to generate a secondary hydroxyl group. This secondary hydroxyl group is blocked by the ester residue of the active ester compound (B1). Therefore, the dielectric loss tangent of the cured product is reduced.

In one embodiment, the structure represented by the above formula (B) is preferably at least one selected from the following formulas (B-1) to (B-6).

In formulas (B-1) to (B-6),
R ¹ is 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,

R ² is each 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 a linear alkylene group having 2 to 6 carbon atoms, an ether a bond, a carbonyl group, a carbonyloxy group, a sulfide group, or a sulfone group,
n is an integer from 0 to 4, and p is an integer from 1 to 4.

The structures represented by the above formulas (B-1) to (B-6) are all highly oriented structures, so when an active ester compound (B1) containing them is used, the resulting thermosetting The cured product of the resin composition has a low dielectric loss tangent in a high frequency band.
Among them, from the viewpoint of low dielectric loss tangent, active ester compounds having a structure represented by formula (B-2), formula (B-3) or formula (B-5) are preferable, and furthermore, active ester compounds having a structure represented by formula (B-2), formula (B-3) or formula (B-5) are preferable. An active ester compound having a structure in which n is 0, a structure in which X in formula (B-3) is an ether bond, or a structure in which two carbonyloxy groups are at the 4,4'-position in formula (B-5) is more preferable. Further, it is preferable that all R ¹ in each formula are hydrogen atoms.

"Ar'" in formula (1) is an aryl group, for example, 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, 1-naphthyl group or 2-naphthyl group is preferable because a cured product with a particularly low dielectric loss tangent can be obtained.

In this embodiment, [A] in the active ester compound (B1) represented by formula (1) is a substituted or unsubstituted arylene group connected via an aliphatic cyclic hydrocarbon group, and such Examples of the arylene group include a structure obtained by polyaddition reaction of an unsaturated aliphatic cyclic hydrocarbon compound containing two double bonds in one molecule and a phenolic compound.

Examples of the unsaturated aliphatic cyclic hydrocarbon compound containing two double bonds in one molecule include dicyclopentadiene, cyclopentadiene polymer, tetrahydroindene, 4-vinylcyclohexene, and 5-vinyl-2-norbornene. , limonene, etc., and each of these may be used alone or two or more types may be used in combination. Among these, dicyclopentadiene is preferred because it provides a cured product 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, in consideration of performance such as heat resistance, curability, and moldability, it is desirable to use a product with dicyclopentadiene purity of 90% by mass or more.

On the other hand, the phenolic compounds include, for example, phenol, cresol, xylenol, ethylphenol, isopropylphenol, butylphenol, octylphenol, nonylphenol, vinylphenol, isopropenylphenol, allylphenol, phenylphenol, benzylphenol, chlorophenol, bromophenol, Examples include 1-naphthol, 2-naphthol, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, and 2,7-dihydroxynaphthalene, each of which can be used alone. It may be used or two or more types may be used together. Among these, phenol is preferred because it forms an active ester compound with high curability and excellent dielectric properties in a cured product.

In a preferred embodiment, [A] in the active ester compound represented by formula (1) has a structure represented by formula (A). A cured product of a thermosetting resin composition containing an active ester compound in which [A] in formula (1) has the following structure can realize a low dielectric loss tangent in a high frequency band.

In formula (A),
R ³ is 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,
l is 0 or 1, and m is an integer of 1 or more.

Among the active ester curing agents represented by formula (1), more preferable ones include resins represented by the following formulas (1-1), (1-2), and (1-3), Particularly preferred are resins represented by the following formula (1-3).

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 a 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 a repeating unit. It is the average of 0.25 to 3.5.

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 a 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 a repeating unit. It is the average of 0.25 to 3.5.

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 a 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 a repeating unit. It is the average of 0.25 to 3.5.

The active ester compound (B1) represented by the above general formula (A) is a phenolic compound (a) having a structure in which a plurality of aryl groups having a phenolic hydroxyl group are linked via an aliphatic cyclic hydrocarbon group, It can be produced by a known method of reacting an aromatic nucleus-containing dicarboxylic acid or its halide (b) with an aromatic monohydroxy compound (c).

The reaction ratio of the phenolic compound (a), the aromatic nucleus-containing dicarboxylic acid or its halide (b), and the aromatic monohydroxy compound (c) can be adjusted as appropriate depending on the desired molecular design. Among them, since an active ester compound (B1) with higher curability is obtained, the above-mentioned phenolic compound is The ratio of the phenolic hydroxyl group possessed by (a) being in the range of 0.25 to 0.90 mol, and the hydroxyl group possessed by the aromatic monohydroxy compound (c) being in the range of 0.10 to 0.75 mol. It is preferable to use each raw material in such a manner that the phenolic hydroxyl group of the phenolic compound (a) is in the range of 0.50 to 0.75 mol, and the hydroxyl group of the aromatic monohydroxy compound (c) is in the range of 0.50 to 0.75 mol. It is more preferable to use each raw material in a proportion ranging from 0.25 to 0.50 mol.

In addition, the functional group equivalent of the active ester compound (B1) is a cured product with excellent curability and a low dielectric loss tangent, when the total number of aryl carbonyloxy groups and phenolic hydroxyl groups in the resin structure is taken as the number of functional groups in the resin. Therefore, it 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 the thermosetting resin composition of the present embodiment, the content of the active ester compound (B1) and the epoxy resin (A) is such that a cured product with excellent curability and a low dielectric loss tangent can be obtained. It is preferable that the epoxy group in the epoxy resin (A) be in a proportion of 0.8 to 1.2 equivalents per total equivalent of active groups in (B1). Here, the active group in the active ester compound (B1) refers to an arylcarbonyloxy group and a phenolic hydroxyl group contained in the resin structure.

The active ester compound (B1) is preferably 0.5% by mass or more and 15% by mass or less, more preferably 2% by mass or more and 12% by mass or less, and even more preferably 2% by mass in 100% by mass of the thermosetting resin composition. It is used in an amount of 9% by mass or less.
By containing the specific active ester compound (B1) in the above range, the obtained cured product can have better dielectric properties and is further excellent in low dielectric loss tangent.

By using the active ester compound (B1) and the above-mentioned high dielectric constant filler (C) in combination, the thermosetting resin composition of this embodiment has excellent high dielectric constant and low dielectric loss tangent, and can be used in high frequency bands. is also excellent in these effects.
From the viewpoint of the above effects, the active ester compound (B1) is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 2 parts by mass or more and 20 parts by mass, based on 100 parts by mass of the above-mentioned high dielectric constant filler (C). parts, more preferably 3 parts by mass or more and 15 parts by mass or less.

[Phenol curing agent (B2)]
The phenolic curing agent (B2) functions as a curing agent for thermosetting resins such as epoxy resins (A).
The phenolic curing agent (B2) contains a biphenylaralkyl phenol resin and/or a phenol novolac resin.

The thermosetting resin composition may contain a curing agent other than the biphenylaralkyl phenolic resin and the phenol novolac resin.
Examples of the biphenylaralkyl phenol resin include phenol aralkyl resin containing a biphenylene skeleton, naphthol aralkyl resin containing a biphenylene skeleton, and the like.

The thermosetting resin composition of this embodiment can contain a curing agent other than the active ester compound (B1).
As other curing agents, phenolic resin curing agents other than biphenylaralkyl phenol resins and phenol novolac resins, amine compound curing agents, amide compound curing agents, acid anhydride curing agents, etc. are used. These may be used alone or in combination of two or more. Among these, a phenolic resin curing agent may be used.

Examples of the phenolic resin curing agent include cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadiene phenol addition type resin, phenol resin containing a biphenylene skeleton, trimethylolmethane resin, tetraphenylolethane resin, and naphthol. Novolak resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked by bismethylene groups), biphenyl-modified naphthol resin (phenol nuclei are linked by bismethylene groups), Examples include polyhydric phenol compounds such as polyhydric naphthol compounds (linked polyhydric naphthol compounds) and aminotriazine-modified phenol resins (polyhydric phenol compounds whose phenol nuclei are linked with melamine, benzoguanamine, etc.).

Examples of the amine compound curing agent include amine compounds such as diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF ₃ -amine complex, and guanidine derivatives.
Examples of the amide compound curing agent include polyamide resins synthesized from dicyandiamide, a dimer of linolenic acid, and ethylenediamine.
Examples of acid anhydride curing agents include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methyl Hexahydrophthalic anhydride is mentioned.

When using the phenolic curing agent (B2), the blending amount of the phenolic curing agent (B2) is preferably 0.5% by mass or more and 15% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, based on 100% by mass of the thermosetting resin. The amount is 1% by mass or more and 10% by mass or less. By using the curing agent in an amount within the above range, a thermosetting resin composition having excellent curability can be obtained.

[Curing catalyst]
The thermosetting resin composition may also include a curing catalyst.
A curing catalyst is sometimes called a curing accelerator. The curing catalyst is not particularly limited as long as it accelerates the curing reaction of the thermosetting resin, and any known curing catalyst can be used.

Specifically, 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; 2-methylimidazole, 2- Imidazole such as phenylimidazole (imidazole curing accelerator); 1,8-diazabicyclo[5.4.0]undecene-7, benzyldimethylamine, etc. are examples of amidine and tertiary amine; quaternary of amidine and amine; Nitrogen atom-containing compounds such as salts can be mentioned, and only one type may be used, or two or more types may be used.

Among these, from the viewpoint of improving hardenability and obtaining a magnetic material with excellent mechanical strength such as bending strength, it is preferable to include compounds containing phosphorus atoms, such as tetra-substituted phosphonium compounds, phosphobetaine compounds, phosphine compounds and quinone compounds. It is more preferable to include compounds with latent properties such as adducts between phosphonium compounds and silane compounds, tetra-substituted phosphonium compounds, adducts between phosphine compounds and quinone compounds, and adducts between phosphonium compounds and silane compounds. Adducts are particularly preferred.

By using the compound (C) represented by the general formula (1) in combination with a curing catalyst having latent properties, it is possible to obtain a magnetic material with excellent formability and mechanical strength such as bending strength. .

Examples of the organic phosphine 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.

When a curing catalyst is used, its content is preferably 0.05 to 3% by mass, more preferably 0.08 to 2% by mass based on 100% by mass of the thermosetting resin composition. By setting the value within such a numerical range, a sufficient curing accelerating effect can be obtained without excessively deteriorating other properties.

[Inorganic filler]
The thermosetting resin composition of the present embodiment may further contain an inorganic filler in addition to the high dielectric constant filler (C) in order to reduce hygroscopicity, reduce linear expansion coefficient, improve thermal conductivity, and improve strength. can.

Inorganic fillers include fused silica, crystalline silica, alumina, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, forsterite, steatite, spinel, Examples include powders such as mullite and titania, beads made of spherical powders, and glass fibers. These inorganic fillers may be used alone or in combination of two or more. Among the above inorganic fillers, silica is preferred from the viewpoint of reducing the linear expansion coefficient, alumina is preferred from the viewpoint of high thermal conductivity, and the filler shape is preferably spherical from the viewpoint of fluidity during molding and mold abrasion. preferable.

The content of the inorganic filler other than the high dielectric constant filler (C) is preferably 3% in 100% by mass of the solid content of the thermosetting resin composition from the viewpoint of moldability, reduction of thermal expansion, and improvement of strength. It can be in the range of 5% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 50% by mass or less. Within the above range, thermal expansion property reduction and moldability are excellent.
The content of silica may be, for example, 25% by mass or less, preferably 20% by mass or less, and more preferably 15% by mass or less, based on 100% by mass of the solid content of the thermosetting resin composition.
The content of the aluminum base material may be, for example, 40% by mass or less, preferably 38% by mass or less, more preferably 35% by mass or less, based on 100% by mass of the solid content of the thermosetting resin composition.

[Other ingredients]
In addition to the above components, the thermosetting resin composition of this embodiment includes various components such as a silane coupling agent, a mold release agent, an adhesion aid, a coloring agent, a dispersant, and a stress reducing agent, as necessary. can include.

[Thermosetting resin composition]
The thermosetting resin composition of this embodiment can be manufactured by uniformly mixing the above-mentioned components. Examples of the manufacturing method include a method in which raw materials having a predetermined content are sufficiently mixed using a mixer or the like, melt-kneaded using a mixing roll, kneader, extruder, etc., and then cooled and pulverized. The obtained thermosetting resin composition may be made into tablets with a size and mass suitable for molding conditions, if necessary.

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 a high frequency band, so it can be used for high frequencies and, therefore, for shortening circuits and miniaturizing high frequency devices such as communication equipment. can be achieved.

Such thermosetting resin compositions can be used to form part of a high frequency device selected from the group consisting of microstrip antennas, dielectric waveguides, and multilayer antennas.

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.

<Microstrip antenna>
As shown in FIG. 1, the microstrip antenna 10 includes a dielectric substrate 12 formed by curing the above-mentioned thermosetting resin composition, and a radiation conductor plate (radiating element) provided on one surface of the dielectric substrate 12. ) 14, and a ground conductor plate 16 provided on the other surface of the dielectric substrate 12.

The shape of the radiation conductor plate may be rectangular or circular. In this embodiment, an example using a rectangular radiation conductor plate 14 will be explained.

The radiation conductor plate 14 includes any one of a metal material, an alloy of metal materials, a cured product of 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, titanium, and the like. Alloys include multiple metallic materials. The metal paste agent includes one obtained by kneading a powder of a metal material with an organic solvent and a binder. The binder includes epoxy resin, polyester resin, polyimide resin, polyamideimide resin, and polyetherimide resin. Conductive polymers include polythiophene polymers, polyacetylene polymers, polyaniline polymers, polypyrrole polymers, and the like.

As shown in FIG. 1, the microstrip antenna 10 of this embodiment has a radiation conductor plate 14 with a length L and a width W, and resonates at a frequency where L corresponds to an integral multiple of 1/2 wavelength. . When using the dielectric substrate 12 having a high dielectric constant as in this embodiment, the thickness h of the dielectric substrate 12 and the width W of the radiation conductor plate 14 are designed to be sufficiently small with respect to the wavelength.

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

Power 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 coupled feeding and proximity coupled feeding.

In the rear coaxial power feeding, power can be fed from the back surface of the antenna to the radiation conductor plate 14 using a coaxial line or a connector that penetrates the ground conductor plate 16 and the dielectric substrate 12.
In coplanar power feeding, power can be fed to the radiation conductor plate 14 using a microstrip line (not shown) arranged on the same plane as the radiation conductor plate 14.

In the slot coupled power supply, another dielectric substrate (not shown) is provided to sandwich the ground conductor plate 16, and the radiation conductor plate 14 and the microstrip line are formed on separate dielectric substrates. The radiation conductor plate 14 is excited by electromagnetically coupling the radiation conductor plate 14 and the microstrip line through the slots formed in the ground conductor plate 16.

In the close-coupled power supply, the dielectric substrate 12 has a laminated structure, and includes a dielectric substrate on which the radiation conductor plate 14 is formed, and a dielectric substrate on which the strip conductor of the microstrip line and the ground conductor plate 16 are arranged. It is layered. The radiation conductor plate 14 is excited by extending the strip conductor of the microstrip line below the radiation conductor plate 14 and electromagnetically coupling the radiation conductor plate 14 and the microstrip line.

FIGS. 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 numbers, and description thereof will be omitted as appropriate.
As shown in FIG. 2(a), the microstrip antenna 20 includes a dielectric substrate 22, a radiation conductor plate 14 provided on one surface of the dielectric substrate 22, and a radiation conductor plate 14 provided on the other surface of the dielectric substrate 22. The radiation conductor plate 16 includes a ground conductor plate 16 , and a high dielectric substrate (high dielectric material) 24 disposed opposite to the radiation conductor plate 14 . The dielectric substrate 22, the radiation conductor plate 14, and the high dielectric substrate 24 can be configured to be separated by a predetermined distance via a spacer 26.
The dielectric substrate 22 is made of a low dielectric constant substrate such as a Teflon substrate.
The high dielectric substrate 24 is constituted by a dielectric substrate formed by curing the above-mentioned resin composition.
The gap between the dielectric substrate 22 and the high dielectric substrate 24 may be a space, or may be filled with a dielectric material.
Alternatively, as shown in a microstrip antenna 20' in FIG. 2(b), a structure may be adopted in which a high dielectric substrate 24 is brought into contact with the upper surface of the radiation conductor plate 14.

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

<Multilayer antenna>
In this embodiment, the multilayer antenna includes a dielectric sheet formed by curing the thermosetting resin composition of this embodiment.
Specifically, a multilayer antenna is a module in which a circuit including a large number of elements such as capacitors and inductors is printed and stacked on dielectric sheets.

<Second invention>
The thermosetting resin composition of the second embodiment includes an epoxy resin (A), a curing agent (B), and a high dielectric constant filler (C).
Each component will be explained below.

[Epoxy resin (A)]
Examples of the epoxy resin (A) include bisphenol A epoxy resin, bisphenol F epoxy resin, naphthalene epoxy resin, dicyclopentadiene epoxy resin, glycidylamine epoxy resin, and naphthol aralkyl epoxy resin. and includes at least one selected from these.
In this embodiment, the epoxy resin (A) is preferably a naphthol aralkyl-type epoxy resin or a dicyclopentadiene-type epoxy resin, and more preferably a naphthol aralkyl-type epoxy resin.
The epoxy resin (A) can contain a combination of other epoxy resins such as biphenylaralkyl epoxy resins.

From the viewpoint of the effects of the present invention, the epoxy resin (A) can be contained in an amount of 5% by mass or more and 20% by mass or less, preferably 10% by mass or more and 15% by mass or less, based on the entire thermosetting resin composition.

[Curing agent (B)]
In this embodiment, the curing agent (B) includes an active ester curing agent (B1) and/or a phenolic curing agent (B2).
(Active ester curing agent (B1))
As the active ester curing agent (active ester compound) (B1), a compound having one or more active ester groups in one molecule can be used. Among these, active ester curing agents (B1) contain ester groups with high reactivity in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Compounds having two or more are preferred.
In this embodiment, by including the above-mentioned specific epoxy resin (A) in combination with an active ester curing agent (B1) as a curing agent (B), a dielectric material with excellent high dielectric constant and low dielectric loss tangent is produced. A body substrate can be obtained.

As a preferable specific example of the active ester curing agent (B1), the same active ester compounds as described in the embodiment of the first invention can be used.

The active ester curing agent (B1) used in the present invention comprises a phenolic compound (a) having a structure in which a plurality of aryl groups having a phenolic hydroxyl group are linked via an aliphatic cyclic hydrocarbon group, and an aromatic nucleus-containing It can be produced by a known method of reacting a dicarboxylic acid or its halide (b) with an aromatic monohydroxy compound (c).

The reaction ratio of the phenolic compound (a), the aromatic nucleus-containing dicarboxylic acid or its halide (b), and the aromatic monohydroxy compound (c) can be adjusted as appropriate depending on the desired molecular design. Among them, since an active ester curing agent (B1) with higher curability is obtained, the above-mentioned phenol is The phenolic hydroxyl group of the compound (a) is in the range of 0.25 to 0.90 mol, and the hydroxyl group of the aromatic monohydroxy compound (c) is in the range of 0.10 to 0.75 mol. It is preferable to use each raw material in a proportion such that the phenolic hydroxyl group possessed by the phenolic compound (a) is in the range of 0.50 to 0.75 mol, and the phenolic hydroxyl group possessed by the aromatic monohydroxy compound (c) is in the range of 0.50 to 0.75 mol. It is more preferable to use each raw material in a proportion such that the group contains 0.25 to 0.50 moles.

In addition, the functional group equivalent of the active ester curing agent (B1) is defined as the number of functional groups in the resin, which is the sum of the aryl carbonyloxy groups and phenolic hydroxyl groups in the resin structure. It 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 the thermosetting resin composition of the present embodiment, the blending amount of the active ester curing agent (B1) and the epoxy resin (A) is determined so that a cured product with excellent curability and low dielectric loss tangent can be obtained. The ratio is preferably such that the amount of epoxy groups in the epoxy resin (A) is 0.8 to 1.2 equivalents per total equivalent of active groups in the ester curing agent (B1). Here, the active group in the active ester curing agent (B1) refers to an arylcarbonyloxy group and a phenolic hydroxyl group contained in the resin structure.

In the composition of the present embodiment, the active ester curing agent (B1) is preferably 0.2% by mass or more and 15% by mass or less, more preferably 0.5% by mass, based on the entire thermosetting resin composition. It is used in an amount of 1.0% by mass or more and 7% by mass or less, more preferably 1.0% by mass or more and 7% by mass or less.
By containing the specific active ester curing agent (B1) in the above range, the resulting cured product can have better dielectric properties and is further excellent in low dielectric loss tangent.

By using the active ester curing agent (B1) in combination with the high dielectric constant filler (C) described below, the resin composition of this embodiment has excellent high dielectric constant and low dielectric loss tangent, and can be used in high frequency bands. is also excellent in these effects.
From the viewpoint of the above effects, the active ester curing agent (B1) is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 2 parts by mass, based on 100 parts by mass of the high dielectric constant filler (C) described below. It can be contained in an amount of at least 20 parts by mass, more preferably at least 3 parts by mass and at most 15 parts by mass.

Incidentally, as described in JP-A No. 2020-90615, the present applicant has developed a resin composition containing an epoxy resin and a predetermined active ester curing agent in a semiconductor encapsulation application different from the present invention. We are developing. The present invention differs from the technique described in the publication in that it contains a high dielectric constant filler. In addition, since it contains a high dielectric constant filler, the action and effect of the combination of active ester curing agent and epoxy resin are different in that it has a high dielectric constant and also has excellent high dielectric constant and low dielectric loss tangent in high frequency bands. are doing.

(Phenol curing agent (B2))
Examples of the phenolic curing agent (B2) include phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin, naphthol aralkyl resin, trimethylolmethane resin, tetra Phenylolethane resin, naphthol novolak resin, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin (a polyhydric phenol compound in which phenol nuclei are linked by bismethylene groups), biphenyl-modified naphthol resin ( Examples include polyhydric phenol compounds such as polyhydric naphthol compounds (polyhydric naphthol compounds in which phenol nuclei are linked by bismethylene groups) and aminotriazine-modified phenol resins (polyhydric phenol compounds in which phenol nuclei are linked by melamine, benzoguanamine, etc.).

The blending amount of the phenolic curing agent (B2) is preferably 20% by mass or more and 70% by mass or less based on the epoxy resin (A). By using the curing agent in an amount within the above range, a resin composition having excellent curability can be obtained.

When the curing agent (B) contains an active ester curing agent (B1) and a phenolic curing agent (B2), the content ratio of the phenolic curing agent b to the active ester curing agent a (b (parts by mass)/ a (parts by mass)) is preferably 0.5 or more and 8 or less, more preferably 1 or more and 5 or less, and still more preferably 1.5 or more and 3 or less.
By containing the active ester curing agent (B1) and the phenolic curing agent (B2) in the above ratio, the resulting cured product can have better dielectric properties and is further excellent in low dielectric loss tangent.

In the composition of the present embodiment, the curing agent (B) containing the active ester curing agent (B1) and/or the phenolic curing agent (B2) is preferably 0.00% of the total thermosetting resin composition. It is used in an amount of 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 still more preferably 1.0% by mass or more and 7% by mass or less.
By containing the curing agent (B) in the above range, the obtained cured product can have better dielectric properties and is further excellent in low dielectric loss tangent.

[High dielectric constant filler (C)]
In this embodiment, the high dielectric constant filler (C) includes calcium titanate, strontium titanate, magnesium titanate, magnesium zirconate, strontium zirconate, bismuth titanate, zirconium titanate, Examples include zinc titanate, barium zirconate, calcium zirconate titanate, lead zirconate titanate, barium magnesium niobate, calcium zirconate, and at least one selected from these.
From the viewpoint of the effects of the present invention, the high dielectric constant filler (C) is preferably at least one selected from calcium titanate, strontium titanate, and magnesium titanate; Magnesium is more preferred.

The shape of the high dielectric constant filler (C) is granular, amorphous, flake, etc., and these shapes of the high dielectric constant filler (C) can be used in any ratio. The average particle diameter of the high dielectric constant filler (C) is preferably 0.1 μm or more and 50 μm or less, more preferably 0.3 μm or more and 20 μm or less, from the viewpoint of the effects of the present invention and fluidity/fillability. Preferably it is 0.5 μm or more and 10 μm or less.

The content of the high dielectric constant filler (C) is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more in 100% by mass of the thermosetting resin composition. be. The upper limit is about 80% by mass or more.
When the amount of the high dielectric constant filler (C) added is within the above range, the obtained cured product has a high dielectric constant and a low dielectric loss tangent, and is also excellent in producing molded products.

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

Specifically, 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; 2-methylimidazole, 2- Imidazole such as phenylimidazole (imidazole curing accelerator); 1,8-diazabicyclo[5.4.0]undecene-7, benzyldimethylamine, etc. are examples of amidine and tertiary amine; quaternary of amidine and amine; Nitrogen atom-containing compounds such as salts can be mentioned, and only one type may be used, or two or more types may be used.

Among these, from the viewpoint of improving hardenability and obtaining a magnetic material with excellent mechanical strength such as bending strength, it is preferable to include compounds containing phosphorus atoms, such as tetra-substituted phosphonium compounds, phosphobetaine compounds, phosphine compounds and quinone compounds. It is more preferable to include compounds with latent properties such as adducts between phosphonium compounds and silane compounds, tetra-substituted phosphonium compounds, adducts between phosphine compounds and quinone compounds, and adducts between phosphonium compounds and silane compounds. Adducts are particularly preferred.

By using a combination of an active ester curing agent represented by the general formula (1) and a curing catalyst having latent properties, it is possible to obtain a magnetic material that has better formability and mechanical strength such as bending strength. can.

Examples of the organic phosphine 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 the tetra-substituted phosphonium compound include compounds represented by the following general formula (6).

In general formula (6),
P represents a phosphorus atom.
R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent 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, and a thiol group in its 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 in an aromatic ring.
x and y are 1 to 3, z is 0 to 3, and x=y.

The compound represented by 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, and an aromatic organic acid anion is generated in the solution system. Then, by adding water, the compound represented by general formula (6) can be precipitated. In the compound represented by general formula (6), R ⁴ , R ⁵ , R ⁶ and R ⁷ bonded to the phosphorus atom are phenyl groups, and AH is a compound having a hydroxyl group in the aromatic ring, that is, a phenol. , and A is preferably an anion of the phenol. The above-mentioned phenols include monocyclic phenols such as phenol, cresol, resorcinol, and catechol; condensed polycyclic phenols such as naphthol, dihydroxynaphthalene, and anthraquinol; and bisphenols such as bisphenol A, bisphenol F, and bisphenol S; Examples include polycyclic phenols such as phenylphenol and biphenol.

Examples of the phosphobetaine compound include a compound represented by the following general formula (7).

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

The compound represented by 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, and the diazonium group of the triaromatic substituted phosphine and the diazonium salt is substituted.

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

In general formula (8),
P represents a phosphorus atom.
R ¹⁰ , R ¹¹ and R ¹² represent 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 from each other.

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 from each other, and R ¹⁴ and R ¹⁵ are bonded to form a cyclic structure. You can.

Examples of phosphine compounds used in the adduct of a phosphine compound and a quinone compound include triphenylphosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, trinaphthylphosphine, tris(benzyl)phosphine, etc. It is preferable that the substituent is substituted or has a substituent such as an alkyl group or an alkoxyl group, and examples of the substituent such as an alkyl group or an alkoxyl group include those having 1 to 6 carbon atoms. Triphenylphosphine is preferred from the viewpoint of availability.

Furthermore, examples of the quinone compound used in the adduct of a phosphine compound and a quinone compound include benzoquinone and anthraquinones, and among them, p-benzoquinone is preferred from the viewpoint of storage stability.

As a method for producing an adduct of a phosphine compound and a quinone compound, the adduct can be obtained by contacting and mixing both the organic tertiary phosphine and the benzoquinone in a solvent that can dissolve them. The solvent is preferably a ketone such as acetone or methyl ethyl ketone, which has low solubility in the adduct. However, it is not limited to this.

In the compound represented by general formula (8), R ¹⁰ , R ¹¹ and R ¹² bonded to the phosphorus atom are phenyl groups, and R ¹³ , R ¹⁴ and R ¹⁵ are hydrogen atoms, that is, 1, A compound to which 4-benzoquinone and triphenylphosphine are added is preferred in that it lowers the thermal modulus of the cured product of the sealing resin composition.

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

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

R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ each represent an organic group having an aromatic ring or a heterocycle, or an aliphatic group, and may be the same or different from each other.
R ²⁰ is an organic group bonded to groups Y ² and Y ³ .
R ²¹ is an organic group bonded to groups Y ⁴ and Y ⁵ .

Y ² and Y ³ represent a group formed by a proton-donating group releasing a proton, and the groups Y ² and Y ³ in the same molecule bond to a silicon atom to form a chelate structure.

Y ⁴ and Y ⁵ represent a group formed by a proton-donating group releasing a proton, and the groups Y ⁴ and Y ⁵ in the same molecule bond to a silicon atom to form a chelate structure.
R ²⁰ and R ²¹ may be the same or different from each other, 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 heterocycle, or an aliphatic group.

In general formula (9), R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ are, for example, phenyl group, methylphenyl group, methoxyphenyl group, hydroxyphenyl group, naphthyl group, hydroxynaphthyl group, benzyl group, methyl group. , ethyl group, n-butyl group, n-octyl group, cyclohexyl group, etc. Among these, alkyl groups such as phenyl group, methylphenyl group, methoxyphenyl group, hydroxyphenyl group, hydroxynaphthyl group, and alkoxy groups , an aromatic group having a substituent such as a hydroxyl group, or an unsubstituted aromatic group is more preferable.

In general formula (9), R ²⁰ is an organic group bonded to Y ² and Y ³ . Similarly, R ²¹ is an organic group that is bonded to groups Y ⁴ and Y ⁵ . Y ² and Y ³ are groups formed by a proton-donating group releasing protons, and the groups Y ² and Y ³ in the same molecule bond to a silicon atom to form a chelate structure. Similarly, Y ⁴ and Y ⁵ are groups formed by a proton-donating group releasing protons, and the groups Y ⁴ and Y ⁵ in the same molecule combine with a silicon atom to form a chelate structure. The groups R ²⁰ and R ²¹ may be the same or different from each other, and the groups Y ² , Y ³ , Y ⁴ and Y5 may be the same or different from each other. The groups represented by -Y ² -R ²⁰ -Y ³ - and Y ⁴ -R ²¹ -Y ⁵ - in general formula (9) are groups in which the proton donor releases two protons. As a proton donor, an organic acid having at least two carboxyl groups or hydroxyl groups in the molecule is preferable, and furthermore, an organic acid having at least two carboxyl groups or hydroxyl groups in the molecule constituting the aromatic ring is preferable. An aromatic compound having at least two hydroxyl groups is preferred, and an aromatic compound having at least two hydroxyl groups on adjacent carbons constituting an aromatic ring is more preferred, such as catechol, pyrogallol, 1,2-dihydroxynaphthalene, 2,3-dihydroxy Naphthalene, 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 Examples include alcohol, 1,2-cyclohexanediol, 1,2-propanediol, and glycerin, but among these, catechol, 1,2-dihydroxynaphthalene, and 2,3-dihydroxynaphthalene are more preferred.

^Z1 in the general formula (9) represents an organic group or aliphatic group having an aromatic ring or a heterocycle, and specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group. and aliphatic hydrocarbon groups such as octyl groups, aromatic hydrocarbon groups such as phenyl, benzyl, naphthyl, and biphenyl groups, glycidyloxy groups such as glycidyloxypropyl, mercaptopropyl, and aminopropyl groups, and mercapto Among these, methyl, ethyl, phenyl, naphthyl, and biphenyl groups are more preferable in terms of thermal stability. preferable.
A method for producing an adduct of a phosphonium compound and a silane compound is, for example, as follows.

A silane compound such as phenyltrimethoxysilane and a proton donor such as 2,3-dihydroxynaphthalene are added and dissolved in a flask containing methanol, and then a sodium methoxide-methanol solution is added dropwise while stirring at room temperature. Furthermore, when a solution prepared in advance in which a tetra-substituted phosphonium halide such as tetraphenylphosphonium bromide is dissolved in methanol is added dropwise thereto under stirring at room temperature, crystals are precipitated. When the precipitated crystals are filtered, washed with water, and dried under vacuum, an adduct of a phosphonium compound and a silane compound is obtained.

When a curing catalyst is used, its content is preferably 0.01 to 1% by mass, more preferably 0.02 to 0.8% by mass, based on the entire resin composition. By setting the value within such a numerical range, a sufficient curing accelerating effect can be obtained without excessively deteriorating other properties.

[Inorganic filler]
The thermosetting resin composition of the present embodiment may further contain an inorganic filler in addition to the high dielectric constant filler (C) in order to reduce hygroscopicity, reduce linear expansion coefficient, improve thermal conductivity, and improve strength. I can do it.

Inorganic fillers include fused silica, crystalline silica, alumina, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, silicon nitride, aluminum nitride, boron nitride, beryllia, zirconia, zircon, forsterite, steatite, spinel, Examples include powders such as mullite and titania, beads made of spherical powders, and glass fibers. These inorganic fillers may be used alone or in combination of two or more. Among the above inorganic fillers, fused silica is preferred from the viewpoint of reducing the coefficient of linear expansion, and alumina is preferred from the viewpoint of high thermal conductivity, and the shape of the filler is spherical from the viewpoint of fluidity during molding and mold abrasion resistance. is preferred.

The blending amount of the inorganic filler other than the high dielectric constant filler (C) is preferably 15% by mass based on the entire thermosetting resin composition from the viewpoint of moldability, reduction of thermal expansion, and improvement of strength. The content can be in the range of 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less. Within the above range, thermal expansion property reduction and moldability are excellent.

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

[Thermosetting resin composition]
The thermosetting resin composition of this embodiment can contain a combination of the following epoxy resin (A), the following curing agent (B), and the following high dielectric constant filler (C).
(Epoxy resin (A))
Contains at least one selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, naphthalene epoxy resin, dicyclopentadiene epoxy resin, glycidylamine epoxy resin, and naphthol aralkyl epoxy resin.
Preferably, it contains at least one selected from the group consisting of dicyclopentadiene type epoxy resins and naphthol aralkyl type epoxy resins.
More preferably, it contains at least one selected from the group consisting of naphthol aralkyl type epoxy resins.

(Curing agent (B))
Contains an active ester curing agent (B1) and/or a phenol curing agent (B2).
It preferably contains an active ester curing agent (B1).
(Active ester curing agent (B1))
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 novolak, and active ester curing agents containing a benzoylated product of phenol novolac. It contains at least one selected from the group consisting of agents.
Preferably, at least one selected from an active ester curing agent containing a naphthalene structure and an active ester curing agent containing a dicyclopentadiene type diphenol structure is included.
More preferably, it is an active ester curing agent having a structure represented by the general formula (1).

(High dielectric constant filler (C))
Calcium titanate, strontium titanate, magnesium titanate, magnesium zirconate, strontium zirconate, bismuth titanate, zirconium titanate, zinc titanate, barium zirconate, calcium zirconate titanate, lead zirconate titanate, niobate Contains at least one selected from barium magnesium acid and calcium zirconate.
Preferably, at least one selected from calcium titanate, strontium titanate, and magnesium titanate is included.
More preferably, it contains at least one selected from calcium titanate and magnesium titanate.
Note that the above-mentioned epoxy resin (A), curing agent (B) containing an active ester curing agent and/or phenol curing agent, and high dielectric constant filler (C) may be used in any combination of their respective examples. be able to.

Furthermore, the thermosetting resin composition of this embodiment,
The epoxy resin (A) can be contained in 100% by mass of the composition, preferably in an amount of 5% by mass or more and 20% by mass or less, more preferably 10% by mass or more and 15% by mass or less,
The curing agent (B) is contained in 100% by mass of the composition, 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 1.0% by mass. % or more and 7% by mass or less,
The high dielectric constant filler (C) can be contained in 100% by mass of the composition, preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more. The upper limit is 80% by mass.

In this embodiment, the above-mentioned epoxy resin (A), a curing agent (B) containing an active ester curing agent, and a high dielectric constant filler (C) are included in combination, thereby achieving a high dielectric constant and It is possible to provide a thermosetting resin composition that provides an excellent dielectric substrate with a low dielectric loss tangent.

The thermosetting resin composition of this embodiment can be manufactured by uniformly mixing the above-mentioned components. Examples of the manufacturing method include a method in which a predetermined amount of raw materials is sufficiently mixed using a mixer, etc., then melt-kneaded using a mixing roll, kneader, extruder, etc., and then cooled and pulverized. The obtained thermosetting resin composition may be made into tablets with a size and mass suitable for molding conditions, if necessary.

The thermosetting resin composition of this embodiment has a spiral flow length of 50 cm or more, preferably 55 cm or more, and more preferably 60 cm or more. Therefore, the thermosetting resin composition of this embodiment has excellent moldability.

In the spiral flow test, for example, using a low-pressure transfer molding machine (KTS-15 manufactured by Kotaki Seiki Co., Ltd.), injection is performed at a mold temperature of 175°C into a mold for spiral flow measurement according to EMMI-1-66. This can be done by injecting the resin molding material under conditions of a pressure of 6.9 MPa and a curing time of 120 seconds and measuring the flow length.

Further, the thermosetting resin composition of the present embodiment has a rectangular pressure of 0.1 MPa or more, preferably 0.15 MPa or more, and more preferably 0.20 MPa or more, as measured under the following conditions.
The rectangular pressure is a parameter of melt viscosity, and the smaller the value, the lower the melt viscosity. Since the thermosetting resin composition of this embodiment has a rectangular pressure within the above range, it has excellent mold filling properties during molding.

(conditions)
Using a low-pressure transfer molding machine, the thermosetting resin composition was injected into a rectangular channel with ^a width of 13 mm, a thickness of 1 mm, and a length of 175 mm under conditions of a mold temperature of 175° C. and an injection speed of 177 mm 3 /sec. Then, a pressure sensor buried at a position 25 mm from the upstream end of the flow path measures the change in pressure over time, calculates the minimum pressure when the thermosetting resin composition is flowing, and calculates this minimum pressure as the rectangular pressure. shall be.

The thermosetting resin composition of this embodiment has the following dielectric constant and dielectric loss tangent (tan δ) in a cured product cured by heating at 200° C. for 90 minutes.
The dielectric constant at 25 GHz measured by the cavity resonator method can be 10 or more, preferably 12 or more, more preferably 13 or more, particularly preferably 14 or more.
The dielectric loss tangent (tan δ) at 25 GHz measured by the cavity resonator method can be 0.04 or less, preferably 0.03 or less, more preferably 0.02 or less, particularly preferably 0.015 or less.

Since the cured product obtained from the thermosetting resin composition of this embodiment has excellent high dielectric constant and low dielectric loss tangent in high frequency bands, it is possible to achieve high frequencies and shorten circuits and miniaturize communication equipment, etc. It can be suitably used as a material for forming a microstrip antenna, a material for forming a dielectric waveguide, a material for forming an electromagnetic wave absorber, etc.

<Microstrip antenna>
The microstrip antenna of this embodiment has the structure shown in FIGS. 1, 2(a) and 2(b) similarly to the embodiment of the first invention, and thus the description thereof will be omitted.

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

<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. The electromagnetic wave absorber can be used as a λ/4 type radio wave absorber having high radio wave absorption performance.
Examples of the support include resin base materials. The support can protect the resistive film and improve its durability as a 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. Its thickness is about 10 μm or more and 2000 μm or less.
The reflective layer can function as a radio wave reflective layer, and includes, 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 within a range that does not impair the effects of the present invention.

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto.
An example of the first invention (claims 1 to 14 and 23 to 25 as filed) and the first embodiment is shown in Example A.
Example B shows an example of the second invention (Claims 15 to 22 and 23 to 25 as filed) and the second embodiment.

<Example A>
(Examples A1 to A19, Comparative Examples A1 to A4)
<Preparation of thermosetting resin composition>
The following raw materials were mixed in the contents shown in Table 1 using a mixer at room temperature, and then kneaded with rolls at 70 to 100°C. Next, the obtained kneaded material was cooled and then ground to obtain a powdery thermosetting resin composition. Then, a tablet-shaped thermosetting resin composition was obtained by compression molding under high pressure.

Information on the raw materials in Table 1 is shown below.

(Inorganic filler)
・Inorganic filler 1: Fused spherical silica (average particle size: 31 μm)
・Inorganic filler 2: Fused spherical silica (average particle size: 0.6 μm)
・Inorganic filler 3: Alumina (average particle size: 0.6 μm)
・Inorganic filler 4: Alumina (average particle size: 30 μm)

(High dielectric constant filler)
・High dielectric constant filler 1: Calcium titanate (average particle size: 2.0 μm)
・High dielectric constant filler 2: Calcium titanate (average particle size: 2.7 μm)
・High dielectric constant filler 3: Calcium titanate (average particle size: 1.2 μm)
・High dielectric constant filler 4: Strontium titanate (average particle size: 1.6 μm)
・High dielectric constant filler 5: Magnesium titanate (average particle size: 0.8 μm)
The particle size distribution of the inorganic filler and the high dielectric constant filler was measured using a laser diffraction scattering method.
In addition, in the volume frequency particle size distribution of the high dielectric constant filler 1 measured by laser diffraction scattering method, the particle diameter at which the cumulative value is 10% is D ₁₀ , the particle diameter at which the cumulative value is 50% is D 50 , and the cumulative value is D ₅₀ . When the particle diameter at which the value is 90% is D ₉₀ , D ₁₀ is 0.7 μm, D ₅₀ is 2.0 μm, D ₉₀ is 7.5 μm, (D ₉₀ - D ₁₀ )/D ₅₀ is 3.4. Met.

(thermosetting resin)
・Epoxy resin 1: Biphenylaralkyl epoxy resin (NC3000L, manufactured by Nippon Kayaku Co., Ltd.)
・Epoxy resin 2: Biphenyl type epoxy resin (YY-4000K, manufactured by Mitsubishi Chemical Corporation)
・Epoxy resin 3: 2,3-epoxypropyl 2-(4,4-dimethylpentan-2-yl)-5,7,7-trimethyloctanoate (Nissan Chemical Co., Ltd., FOLDI E101)
・Epoxy resin 4: Bisphenol fluorene epoxy resin (TBIS-GG, manufactured by Taoka Chemical Industry Co., Ltd.)
・Epoxy resin 5: Bisphenol fluorene epoxy resin (TBIS-RXG, manufactured by Taoka Chemical Industry Co., Ltd.)
・Epoxy resin 6: Dicyclopentadiene type epoxy resin (HP-7200L, manufactured by DIC)
・Epoxy resin 7: Branched alkyl chain epoxy resin (YL9057, Mitsubishi Chemical)
・Epoxy resin 8: Fluorene type epoxy resin (Oxol PG-100, manufactured by Osaka Gas Chemical Co., Ltd.)
・Epoxy resin 9: Naphthol aralkyl type epoxy resin (ESN-475V, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)

(Active ester compound)
・Active ester compound 1: Active ester compound prepared by the following preparation method In a flask equipped with a thermometer, dropping funnel, condenser tube, fractionator tube, and stirrer, add 279.1 g of biphenyl-4,4'-dicarboxylic acid dichloride ( The number of moles of acid chloride groups: 2.0 moles) and 1338 g of toluene were charged, and the system was replaced with nitrogen under reduced pressure to dissolve them. Next, 96.5 g (0.67 mol) of α-naphthol and 219.5 g (mol number of phenolic hydroxyl group: 1.33 mol) of dicyclopentadiene phenol resin were charged, and the system was replaced with nitrogen under reduced pressure to dissolve them. Ta. Thereafter, while performing a nitrogen gas purge, the inside of the system was controlled at 60° C. or lower, and 400 g of a 20% aqueous sodium hydroxide solution was added dropwise over a period of 3 hours. Stirring was then continued under these conditions for 1.0 hour. After the reaction was completed, the mixture was allowed to stand still for liquid separation, and the aqueous layer was removed. Furthermore, water was added to the toluene phase in which the reactants were dissolved, and the mixture was stirred and mixed for about 15 minutes, and the mixture was allowed to stand still for liquid separation to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Thereafter, water was removed by dehydration using a decanter to obtain an active ester resin in the form of a toluene solution with a nonvolatile content of 65%. When the structure of the obtained active ester resin was confirmed, it had a structure in which R ¹ and R ³ are hydrogen atoms, Z is a naphthyl group, and l is 0 in the above formula (1-1). Furthermore, the average value k of the repeating units was calculated from the reaction equivalence ratio and was in the range of 0.5 to 1.0.

・Active ester compound 2: Active ester compound prepared by the following preparation method Into a flask equipped with a thermometer, dropping funnel, cooling tube, fractionating tube, and stirrer, add 203.0 g of 1,3-benzenedicarboxylic acid dichloride (acid chloride). The number of moles of the group: 2.0 moles) and 1338 g of toluene were charged, and the system was replaced with nitrogen under reduced pressure to dissolve them. Next, 96.5 g (0.67 mol) of α-naphthol and 219.5 g (mol number of phenolic hydroxyl group: 1.33 mol) of dicyclopentadiene phenol resin were charged, and the system was replaced with nitrogen under reduced pressure to dissolve them. Ta. Thereafter, while performing a nitrogen gas purge, the inside of the system was controlled at 60° C. or lower, and 400 g of a 20% aqueous sodium hydroxide solution was added dropwise over a period of 3 hours. Stirring was then continued under these conditions for 1.0 hour. After the reaction was completed, the mixture was allowed to stand still for liquid separation, and the aqueous layer was removed. Furthermore, water was added to the toluene phase in which the reactants were dissolved, and the mixture was stirred and mixed for about 15 minutes, and the mixture was allowed to stand still for liquid separation to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Thereafter, water was removed by dehydration using a decanter to obtain an active ester resin in the form of a toluene solution with a nonvolatile content of 65%. When the structure of the obtained active ester resin was confirmed, it had a structure in which R ¹ and R ³ are hydrogen atoms, Z is a naphthyl group, and l is 0 in the above formula (1-3). The average value k of the repeating units of the active ester resin was calculated from the reaction equivalence ratio and was in the range of 0.5 to 1.0. The obtained active ester resin specifically had a structure represented by the following chemical formula. In the following formula, the average value k of the repeating units was 0.5 to 1.0.

(hardening agent)
・Phenol curing agent 1: Branched alkyl chain phenol novolak resin (ST-007-02, manufactured by Meiwa Kasei Co., Ltd.)

(curing catalyst)
・Curing catalyst 1: Tetraphenylphosphonium-4,4'-sulfonyl diphenolate

(Silane coupling agent)
- Silane coupling agent 1: Phenylaminopropyltrimethoxysilane (CF4083, manufactured by Toray Dow Corning)
・Silane coupling agent 2: 3-mercaptopropyltrimethoxysilane (Sila Ace, manufactured by JNC)

(Additive)
・Coloring agent 1: Black titanium oxide (manufactured by Ako Kasei Co., Ltd.)
・Release agent 1: Glycerin trimontanate (Recolb WE-4, manufactured by Clariant Japan)
- Low stress agent 1: Carboxyl group-terminated butadiene acrylic rubber (CTBN1008SP, manufactured by Ube Industries, Ltd.)

(Evaluation of permittivity and dielectric loss tangent by cavity resonator method)
The obtained thermosetting resin composition was applied to a Si substrate and prebaked 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 under a nitrogen atmosphere, and 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 from the Si substrate and used as a test piece.
The measurement devices used were a network analyzer HP8510C, a synthesized sweeper HP83651A, and a test set HP8517B (all manufactured by Agilent Technologies). These devices and a cylindrical cavity resonator (inner diameter 42 mm, height 30 mm) were set up.
The resonant frequency, 3 dB bandwidth, transmitted power ratio, etc. were measured at a frequency of 18 GHz with and without the test piece inserted into the resonator. Then, by analytically calculating these measurement results using software, dielectric properties such as permittivity (Dk) and dielectric loss tangent (Df) were determined. Note that the measurement mode was TE ₀₁₁ mode.

(Glass transition temperature, coefficient of linear expansion)
The glass transition temperature (Tg) and coefficient of linear expansion (CTE1, CTE2) of the cured product of the obtained thermosetting resin composition were measured as follows. First, a thermosetting 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. A test piece of 10 mm x 4 mm x 4 mm was obtained. Next, the obtained test piece was post-cured at 175°C for 4 hours, and then measured using a thermomechanical analyzer (TMA100, manufactured by Seiko Electronics Co., Ltd.) at a temperature range of 0°C to 320°C and a heating rate. The measurement was performed under the condition of 5°C/min. From this measurement result, the glass transition temperature (Tg), the coefficient of linear expansion below the glass transition temperature (CTE1), and the coefficient of linear expansion above the glass transition temperature (CTE2) were calculated.

(Bending strength, bending modulus)
The obtained thermosetting resin composition was molded using a low-pressure transfer molding machine (KTS-30 manufactured by Kotaki Seiki Co., Ltd.) under conditions of a mold temperature of 130°C, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. Injection molded into a mold. As a result, a molded product with a width of 10 mm, a thickness of 4 mm, and a length of 80 mm was obtained. Next, the obtained molded article was post-cured at 175° C. for 4 hours. In this way, a test piece for mechanical strength evaluation was prepared. Then, the bending strength (N/mm ² ) and flexural modulus (N/mm ² ) of the test piece at room temperature (25°C) or 260°C were measured at a head speed of 5 mm/min in accordance with JIS K 6911. did.

(Rectangular pressure)
Using a low-pressure transfer molding machine (manufactured by NEC Corporation, 40t manual press), a rectangular shape with a width of 13 mm, a thickness of 1 mm, and a length of 175 mm was formed at a mold temperature of 175°C and an injection speed of 177 mm ³ /sec. A thermosetting resin composition was injected into the channel. At this time, a pressure sensor embedded at a position 25 mm from the upstream end of the flow path measures the change in pressure over time, and the lowest pressure (MPa) during flow of the thermosetting resin composition is measured, and this is calculated as the rectangular pressure. And so. The rectangular pressure is a parameter of melt viscosity, and a smaller value indicates a lower melt viscosity.

(Water absorption rate)
The thermosetting resin composition was injection molded using a low pressure transfer molding machine (manufactured by Kotaki Seiki Co., Ltd., KTS-30) under the conditions of a mold temperature of 175 ° C., an injection pressure of 7.4 MPa, and a curing time of 120 seconds. A test piece with a diameter of 50 mm and a thickness of 3 mm was prepared and post-cured at 175° C. for 4 hours. Thereafter, the obtained test piece was humidified for 168 hours in an environment of 85° C. and 85% relative humidity, and the weight change before and after the humidification was measured to determine the moisture absorption rate. The unit is % (mass%).

(Thermal conductivity)
A molded article of 50φ x 50mm was measured at room temperature using a probe type thermal conductivity measuring device (manufactured by Showa Denko K.K.). The unit is W/m℃.

(Die shear strength against copper)
Using a low-pressure transfer molding machine (manufactured by Yamashiro Seiki Co., Ltd., "AV-600-50-TF"), a mold of ^10mm Four test pieces were molded per level. Subsequently, the die shear strength between the test piece and the copper lead frame was measured at room temperature using an automatic die shear measuring device (manufactured by Nordson Advanced Technologies, Model DAGE4000). The average value of the die shear strength of the four test pieces is shown in the table.

(shape retention)
The thermosetting 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. A test piece of x4mm x 4mm was obtained. Next, the obtained test piece was post-cured at 175°C for 4 hours, and then measured using a thermomechanical analyzer (TMA100, manufactured by Seiko Electronics Co., Ltd.) at a temperature range of 0°C to 320°C and a heating rate. The dimensional change rate of the test piece was measured under the condition of 5° C./min.
A test piece with a dimensional change rate of 0.6% or less was evaluated as having good shape retention (○), and a test piece with a dimensional change rate of 0.6% or less was evaluated as poor (x).

(Toughness)
The thermosetting resin composition was measured in accordance with the KIc method specified by ASTM D5045-91. A curable resin composition with a length of 50 mm, width B = 5 mm, and thickness W = 10 mm was given a notch with a depth of 3.5 mm in the thickness direction at the center of the length direction, and was cured at 175 ° C. for 4 hours. . Furthermore, a scratch with a depth of 0.1 mm in the thickness direction was made with a razor at the tip of the notch on the cured product. The total crack length a=3.6 mm. After that, a three-point bending test was performed using STB-1225S type Tensilon manufactured by Orientech Co., Ltd. at a measurement temperature of 25°C, a speed of 10 mm/min, and a distance between supports S = 40 mm, and the fracture toughness value (K1c (MPa・m ^1/2 )) was calculated.
K _IC = ((P _Q × S) / (B × W ^3/2 )) × f (a/W)
f(a/W)=(3(a/W) ^1/2 [1.99-(a/W)(1-a/W){2.15-3.9(a/W)+2.7 (a/W) ² ])/(2{881+2(a/W)}{1-(a/W)} ^3/2 )
Those with a fracture toughness value of 1.8 MPa·m ^1/2 or more were evaluated as having good toughness (◯), and those with a fracture toughness value of less than 1.8 MPa·m ^1/2 were evaluated as poor (×).

(Void suppression)
The thermosetting 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. A test piece of x4mm x 4mm was obtained. The presence or absence of voids in the cross section of the obtained test piece (molded product) was confirmed by SEM observation.
A case in which voids were confirmed in the SEM images at five locations was evaluated as ○, and a case in which voids were observed in one or more of the five locations was evaluated as ×.

(Fillability)
The mold was formed under the following conditions: mold temperature: 175°C, injection speed: 10.5 mm/s, injection pressure: 3.5 MPa, curing time: 120 seconds, tablet size: 40 mmΦ-40 g (molding pressure 8 MPa). A thermosetting resin was injected into a rectangular channel having a width of 5 mm and a slit gap (G) of 25 μm, and the filling length from the upstream tip of the channel was measured.
The filling property was evaluated as good (◯) when the filling length was 8 mm or more, and poor when the filling length was less than 8 mm.

The thermosetting resin compositions of Examples A1 to A19 are superior in high dielectric constant and low dielectric loss tangent in the high frequency band of molded members compared to Comparative Examples A1 to A4, and compared to Comparative Example 3, The shape retention of the member is excellent, and the toughness of the member is better than that of Comparative Examples A1, A2, and A4. Compared with Comparative Example A3, the generation of voids during molding of the member is suppressed. Compared to Example A4, the results showed excellent filling properties during molding of the member.
The thermosetting resin composition of each example can be suitably used to form a part of a high frequency device such as a microstrip antenna, a dielectric waveguide, and a multilayer antenna.

<Example B>
(Examples B1 to B17, Reference Example B1)
The following raw materials were mixed in the amounts shown in Table 3 using a mixer at room temperature, and then roll kneaded at 70 to 100°C. Next, the obtained kneaded product was cooled and then ground to obtain a powdery resin composition. Then, a tablet-shaped resin composition was obtained by compression molding under high pressure.

(Inorganic filler)
・Inorganic filler 1: Fused spherical silica (manufactured by Denka Corporation)

(High dielectric constant filler)
・High dielectric constant filler 1: Calcium titanate (average particle size 2.0 μm)
・High dielectric constant filler 2: Magnesium titanate, (average particle size 0.8 μm, surface treated, manufactured by Titan Kogyo Co., Ltd.)
・High dielectric constant filler 3: Strontium titanate (average particle size 1.6 μm)

(colorant)
・Coloring agent 1: Black titanium oxide (manufactured by Ako Kasei Co., Ltd.)

(coupling agent)
・Coupling agent 1: Phenylaminopropyltrimethoxysilane (CF4083, manufactured by Dow Corning Toray)
・Coupling agent 2: 3-mercaptopropyltrimethoxysilane (Sila Ace, manufactured by JNC)

(Epoxy resin)
・Epoxy resin 1: Biphenylene skeleton-containing phenol aralkyl epoxy resin (NC3000L, manufactured by Nippon Kayaku Co., Ltd.)
・Epoxy resin 2: Naphthol aralkyl type epoxy resin (ESN-475V, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
・Epoxy resin 3: Bisphenol A type epoxy resin (YL6810, manufactured by Mitsubishi Chemical Corporation)
・Epoxy resin 4: Bisphenol F type epoxy resin (jER806H, manufactured by Mitsubishi Chemical Corporation)
・Epoxy resin 5: Phenol aralkyl type epoxy resin (Milex E-XLC-4L (epoxy equivalent 238 g/eq, softening point 62°C), manufactured by Mitsui Chemicals)
・Epoxy resin 6: Naphthalene type epoxy resin (EPICLON HP-4770, manufactured by DIC)
・Epoxy resin 7: Dicyclopentadiene type epoxy resin (EPICLON HP-7200L, manufactured by DIC)
・Epoxy resin 8: Glycidylamine type epoxy resin (jER603, manufactured by Mitsubishi Chemical Corporation)

(hardening agent)
・Curing agent 1: Active ester curing agent prepared by the following preparation method (Preparation method of active ester curing agent)
In a flask equipped with a thermometer, dropping funnel, condenser tube, fractionator tube, and stirrer, add 279.1 g of biphenyl-4,4'-dicarboxylic acid dichloride (number of moles of acid chloride group: 2.0 moles) and 1338 g of toluene. were charged, and the system was replaced with nitrogen under reduced pressure to dissolve them. Next, 96.5 g (0.67 mol) of α-naphthol and 219.5 g (mol number of phenolic hydroxyl group: 1.33 mol) of dicyclopentadiene phenol resin were charged, and the system was replaced with nitrogen under reduced pressure to dissolve them. Ta. Thereafter, while performing a nitrogen gas purge, the inside of the system was controlled at 60° C. or lower, and 400 g of a 20% aqueous sodium hydroxide solution was added dropwise over a period of 3 hours. Stirring was then continued under these conditions for 1.0 hour. After the reaction was completed, the mixture was allowed to stand still for liquid separation, and the aqueous layer was removed. Furthermore, water was added to the toluene phase in which the reactants were dissolved, and the mixture was stirred and mixed for about 15 minutes, and the mixture was allowed to stand still for liquid separation to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Thereafter, water was removed by dehydration using a decanter to obtain an active ester resin in the form of a toluene solution with a nonvolatile content of 65%. When the structure of the obtained active ester resin was confirmed, it had a structure in which R ¹ and R ³ are hydrogen atoms, Z is a naphthyl group, and l is 0 in the above formula (1-1). Furthermore, the average value k of the repeating units was calculated from the reaction equivalence ratio and was in the range of 0.5 to 1.0.

・Curing agent 2: Active ester curing agent prepared by the following preparation method (Preparation method of active ester curing agent)
203.0 g of 1,3-benzenedicarboxylic acid dichloride (number of moles of acid chloride group: 2.0 moles) and 1338 g of toluene were placed in a flask equipped with a thermometer, dropping funnel, cooling tube, fractionating tube, and stirrer. After charging, the system was replaced with nitrogen under reduced pressure to dissolve. Next, 96.5 g (0.67 mol) of α-naphthol and 219.5 g (mol number of phenolic hydroxyl group: 1.33 mol) of dicyclopentadiene phenol resin were charged, and the system was replaced with nitrogen under reduced pressure to dissolve them. Ta. Thereafter, while performing a nitrogen gas purge, the inside of the system was controlled at 60° C. or lower, and 400 g of a 20% aqueous sodium hydroxide solution was added dropwise over a period of 3 hours. Stirring was then continued under these conditions for 1.0 hour. After the reaction was completed, the mixture was allowed to stand still for liquid separation, and the aqueous layer was removed. Furthermore, water was added to the toluene phase in which the reactants were dissolved, and the mixture was stirred and mixed for about 15 minutes, and the mixture was allowed to stand still for liquid separation to remove the aqueous layer. This operation was repeated until the pH of the aqueous layer reached 7. Thereafter, water was removed by dehydration using a decanter to obtain an active ester resin in the form of a toluene solution with a nonvolatile content of 65%. When the structure of the obtained active ester resin was confirmed, it had a structure in which R ¹ and R ³ are hydrogen atoms, Z is a naphthyl group, and l is 0 in the above formula (1-3). The average value k of the repeating units of the active ester resin was calculated from the reaction equivalence ratio and was in the range of 0.5 to 1.0. The obtained active ester resin specifically had a structure represented by the following chemical formula. In the following formula, the average value k of the repeating units was 0.5 to 1.0.

[Curing catalyst]
・Curing catalyst 1: Tetraphenylphosphonium-4,4'-sulfonyl diphenolate

(Additive)
・Silicone 1: Dimethylsiloxane-diglycidine ether copolymer (M69B, manufactured by Sumitomo Bakelite Co., Ltd.)

(Low stress agent)
・Low stress agent 1: Carboxyl group-terminated butadiene acrylic rubber (CTBN1008SP, manufactured by Ube Industries, Ltd.)

(Evaluation of permittivity and dielectric loss tangent by cavity resonator method)
First, a test piece was obtained using a resin composition.
Specifically, the resin compositions prepared in Examples and Comparative Examples were applied to a Si substrate and prebaked 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 under a nitrogen atmosphere, and 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 from the Si substrate and used as a test piece.
The measurement devices used were a network analyzer HP8510C, a synthesized sweeper HP83651A, and a test set HP8517B (all manufactured by Agilent Technologies). These devices and a cylindrical cavity resonator (inner diameter 42 mm, height 30 mm) were set up.
The resonant frequency, 3 dB bandwidth, transmitted power ratio, etc. were measured at a frequency of 25 GHz with and without the test piece inserted into the resonator. Then, by analytically calculating these measurement results using software, dielectric properties such as permittivity (Dk) and dielectric loss tangent (Df) were determined. Note that the measurement mode was TE ₀₁₁ mode.

(Spiral flow measurement)
Using a low-pressure transfer molding machine (KTS-15 manufactured by Kotaki Seiki Co., Ltd.), a mold for spiral flow measurement according to EMMI-1-66 was molded at a mold temperature of 175°C, an injection pressure of 6.9 MPa, and curing. The resin compositions obtained in Examples and Comparative Examples were injected for a time of 120 seconds, and the flow length was measured.

(Gel Time (GT))
The resin compositions of Examples and Comparative Examples were each melted on a hot plate heated to 175° C., and the time (unit: seconds) until hardening was measured while kneading with a spatula.

(molding shrinkage rate)
For each Example and Comparative Example, the molding shrinkage rate (after ASM) of the obtained resin composition was measured after molding (as Mold), and after the molding, it was fully cured and used as a dielectric substrate. The molding shrinkage rate (after PMC) was evaluated under heating conditions (PMC: Post Mold Cure) assumed to be produced.
First, a JIS The molding shrinkage rate (after ASM) was obtained according to K 6911.
Furthermore, the obtained test piece was heat-treated at 175° C. for 4 hours, and the molding shrinkage rate (after PMC) was measured according to JIS K 6911.

(Glass transition temperature, coefficient of linear expansion)
For each Example and Comparative Example, the glass transition temperature (Tg) and coefficient of linear expansion (CTE1, CTE2) of the obtained cured 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. A test piece of 10 mm x 4 mm x 4 mm was obtained. Next, the obtained test piece was post-cured at 175°C for 4 hours, and then measured using a thermomechanical analyzer (TMA100, manufactured by Seiko Electronics Co., Ltd.) at a temperature range of 0°C to 320°C and a heating rate. The measurement was performed under the condition of 5°C/min. From this measurement result, the glass transition temperature (Tg), the coefficient of linear expansion below the glass transition temperature (CTE1), and the coefficient of linear expansion above the glass transition temperature (CTE2) were calculated.

(Evaluation of mechanical strength (bending strength/flexural modulus))
The resin compositions of Examples and Comparative Examples were molded using a low-pressure transfer molding machine (KTS-30 manufactured by Kotaki Seiki Co., Ltd.) under conditions of a mold temperature of 130°C, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. Injection molded into a mold. As a result, a molded product with a width of 10 mm, a thickness of 4 mm, and a length of 80 mm was obtained. Next, the obtained molded article was post-cured at 175° C. for 4 hours. In this way, a test piece for mechanical strength evaluation was prepared. Then, the bending strength (N/mm ² ) and flexural modulus (N/mm ² ) of the test piece at room temperature (25°C) or 260°C were measured at a head speed of 5 mm/min in accordance with JIS K 6911. .

(Measurement of rectangular pressure)
The rectangular pressure of the resin compositions of Examples and Comparative Examples was measured as follows. First, using a low-pressure transfer molding machine (manufactured by NEC Corporation, 40t manual press), a rectangle with a width of 13 mm, a thickness of 1 mm, and a length of 175 mm was formed under the conditions of a mold temperature of 175°C and an injection speed of 177 mm ³ /sec. A resin composition was injected into the shaped channel. At this time, a pressure sensor embedded at a position 25 mm from the upstream end of the flow path measured the change in pressure over time, and the lowest pressure (MPa) during flow of the resin composition was measured, and this was defined as the rectangular pressure. The rectangular pressure is a parameter of melt viscosity, and a smaller value indicates a lower melt viscosity.

From the results in Table 3, it can be seen that according to the thermosetting resin composition of the present invention, a dielectric substrate excellent in high dielectric constant and low dielectric loss tangent, in other words, a dielectric substrate excellent in balance of these properties can be obtained. became clear.

10 Microstrip antenna 12 Dielectric substrate 14 Radiation conductor plate 16 Ground conductor plate 20, 20' Microstrip antenna 22 Dielectric substrate 24 High dielectric substrate 26 Spacer a Cavity part

Claims (25)

(A) epoxy resin,
A thermosetting resin composition comprising (B) a curing agent and (C) a high dielectric constant filler,
The high dielectric constant filler (C) contains 50% by mass or more of calcium titanate particles or 60% by mass or more of strontium titanate particles based on 100% by mass of the solid content of the thermosetting resin composition,
The epoxy resin (A) contains a biphenylaralkyl epoxy resin and/or a biphenyl epoxy resin,
The curing agent (B) contains an active ester compound (B1) and/or a phenolic curing agent (B2),
The active ester compound (B1) is an active ester compound containing a dicyclopentadiene type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester containing a benzoylated product of phenol novolac. Contains at least one selected from compounds,
The phenolic curing agent (B2) contains a biphenylaralkyl phenol resin and/or a phenol novolak resin,
The bending elastic modulus at 260° C., measured according to Procedure 1 below, is 50 N/mm ² or more and 190 N/mm ² or less,
The rectangular pressure, measured according to Procedure 2 below, is 0.2 MPa or more and 8.8 MPa or less,
Thermosetting resin composition.
(Step 1)
The thermosetting resin composition was injection-molded into a mold using a low-pressure transfer molding machine under the conditions of a mold temperature of 130°C, an injection pressure of 9.8 MPa, and a curing time of 300 seconds. A molded product with a length of 80 mm is obtained.
The obtained molded product is post-cured at 175° C. for 4 hours to prepare a test piece.
The flexural modulus (N/mm ² ) of the test piece at 260° C. is measured in accordance with JIS K 6911.
(Step 2)
Using a low-pressure transfer molding machine, the thermosetting resin composition was poured into a rectangular channel with ^a width of 13 mm, a thickness of 1 mm, and a length of 175 mm under conditions of a mold temperature of 175° C. and an injection speed of 177 mm 3 /sec. Injected. At this time, a pressure sensor embedded at a position 25 mm from the upstream end of the flow path measures the change in pressure over time, and the lowest pressure (MPa) during the flow of the thermosetting resin composition is measured, and this is Press. The thermosetting resin composition according to claim 1, wherein the curing agent (B) includes the active ester compound (B1) and the phenolic curing agent (B2). In the volume frequency particle size distribution of the high dielectric constant filler (C) measured by laser diffraction scattering method, the particle diameter at which the cumulative value is 10% is D ₁₀ , the particle diameter at which the cumulative value is 50% is D ₅₀ , and When the particle diameter at which the cumulative value is 90% is _D90 ,
The thermosetting resin composition according to claim 1 or 2, wherein D ₁₀ , D ₅₀ and D ₉₀ satisfy 0.25≦(D ₉₀ −D ₁₀ )/D ₅₀ ≦55. The thermosetting resin composition according to any one of claims 1 to 3, which contains an inorganic filler other than the high dielectric constant filler (C), and the inorganic filler contains silica and/or alumina. Claims 1 to 4, wherein the flexural modulus at 25°C, measured in accordance with JIS K 6911 using the test piece obtained in Step 1 above, is 9000 N/mm ² or more and 28000 N/mm ² or less. The thermosetting resin composition according to any one of the above. Claims 1 to 5, wherein the bending strength at 25°C, measured in accordance with JIS K 6911 using the test piece obtained in step 1 above, is 40 N/mm ² or more and 200 N/mm ² or less. Thermosetting resin composition according to any one of the items. Claims 1 to 3, wherein the bending strength at 260°C, measured in accordance with JIS K 6911 using the test piece obtained in Step 1 above, is 0.1 N/mm ² or more and 10 N/mm ² or less. 6. The thermosetting resin composition according to any one of 6. The thermosetting resin composition according to any one of claims 1 to 7, wherein the cured product of the thermosetting resin composition has a water absorption rate of 0.01% or more and 0.8% or less. The thermosetting resin composition according to any one of claims 1 to 8, wherein the cured product of the thermosetting resin composition has a thermal conductivity of 1.0 W/mK or more and 5.0 W/mK or less. . The thermosetting resin composition according to any one of claims 1 to 9, which has a die shear strength against copper of 5 N/mm ² or more and 50 N/mm ^{2 or less} , as measured by the following procedure.
(procedure)
Using a low-pressure transfer molding machine, the thermosetting resin composition was molded under the conditions of a mold temperature of 175°C, an injection pressure of 10 MPa, and a curing time of 180 seconds, and one 10 mm ² test piece was placed on a copper lead frame. Form 4 pieces per level.
Subsequently, the die shear strength between the test piece and the copper lead frame is measured at room temperature using an automatic die shear measuring device. The die shear strength of four test pieces is adopted. The thermosetting resin composition according to any one of claims 1 to 10, wherein the cured product of the thermosetting resin composition has a glass transition temperature of 90°C or more and 200°C or less. In the cured product of the thermosetting resin composition, the linear expansion coefficient CTE1 in the range below the glass transition temperature is 5 ppm or more and 30 ppm or less, and the linear expansion coefficient CTE2 in the range above the glass transition temperature and 320° C. or less is 10 ppm or more and 100 ppm or less. The thermosetting resin composition according to any one of claims 1 to 11. The thermosetting resin composition according to any one of claims 1 to 12, which is used to form a part of a high frequency device selected from the group consisting of a microstrip antenna, a dielectric waveguide, and a multilayer antenna. . A high frequency device comprising a cured product of the thermosetting resin composition according to any one of claims 1 to 13. (A) an epoxy resin;
(B) a curing agent;
(C) a high dielectric constant filler;
A thermosetting resin composition comprising,
The epoxy resin (A) is selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, naphthalene epoxy resin, dicyclopentadiene epoxy resin, glycidylamine epoxy resin, and naphthol aralkyl epoxy resin. containing at least one species of
The curing agent (B) contains an active ester curing agent (B1) and/or a phenolic curing agent (B2),
The high dielectric constant filler (C) is calcium titanate, strontium titanate, magnesium titanate, magnesium zirconate, strontium zirconate, bismuth titanate, zirconium titanate, zinc titanate, barium zirconate, zircon titanate. A thermosetting resin composition comprising at least one selected from calcium acid, lead zirconate titanate, barium magnesium niobate, and calcium zirconate. The thermosetting resin composition according to claim 15, wherein the high dielectric constant filler (C) is at least one selected from calcium titanate, strontium titanate, and magnesium titanate. The thermosetting resin composition according to claim 15 or 16, wherein the high dielectric constant filler (C) is contained in an amount of 40% by mass or more in 100% by mass of the thermosetting resin composition. The active ester curing agent (B1) includes 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 The thermosetting resin composition according to any one of claims 15 to 17, comprising at least one selected from active ester curing agents including benzoylated phenol novolacs. The thermosetting resin composition according to any one of claims 15 to 18, wherein the active ester curing agent (B1) has a structure represented by the following general formula (1).

(In general formula (1), A is a substituted or unsubstituted arylene group connected 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),

(In the general formula (B), Ar is a substituted or unsubstituted arylene group, and Y is a single bond, a substituted or unsubstituted linear alkylene group having 1 to 6 carbon atoms, or a substituted or unsubstituted is a 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 0 or 1)
k is the average value of repeating units and ranges from 0.25 to 3.5. ) The thermosetting resin composition according to any one of claims 15 to 19, which is used as a material for forming a microstrip antenna. The thermosetting resin composition according to any one of claims 15 to 19, which is used as a material for forming a dielectric waveguide. The thermosetting resin composition according to any one of claims 15 to 19, which is used as a material for forming an electromagnetic wave absorber. A dielectric substrate obtained by curing the thermosetting resin composition according to any one of claims 1 to 13 and claims 15 to 22. A dielectric substrate according to claim 23,
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;
Microstrip antenna. 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 to the radiation conductor plate;
A microstrip antenna comprising:
A microstrip antenna, wherein the high dielectric material is constituted by the dielectric substrate according to claim 23.

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