Resin compositions, cured products, prepregs, resin sheets, laminates, metal foil-clad laminates, and printed circuit boards.

Abstract

The purpose of the present invention is to provide: a resin composition that is ideal for production of an insulating layer for a printed wiring board that has a high dielectric constant, a low dielectric loss tangent, excellent thermal characteristics, excellent laser processability, and high metal foil peeling strength; and a prepreg, a resin sheet, a laminate, a metal foil–clad laminate, and a printed wiring board obtained using the resin composition.　This resin composition includes: a dielectric powder (A) that has a relative permittivity of at least 12.0 at a frequency of 10 GHz as measured in accordance with a cavity resonator perturbation method, an inorganic filler (B) that is different from the dielectric powder (A), has a melting point of no more than 1600°C, and has an absorbance of at least 0.70 at a wavelength of 9.3 μm on an infrared absorption spectrum obtained using Fourier transform infrared spectroscopy, and a thermosetting resin (C).

Description

[Technical Field]

[0001] The present invention relates to resin compositions, cured products, prepregs, resin sheets, laminates, metal foil-clad laminates, and printed circuit boards. [Background technology]

[0002] In recent years, the signal bandwidths of information and communication devices such as PHS and mobile phones, as well as the CPU clock times of computers, have reached the GHz range, and higher frequencies are progressing. The dielectric loss of an electrical signal is proportional to the product of the square root of the relative permittivity of the insulating layer forming the circuit, the dielectric loss tangent, and the frequency of the electrical signal. Therefore, the higher the frequency of the signal used, the greater the dielectric loss. Since increased dielectric loss attenuates the electrical signal and impairs the reliability of the signal, it is necessary to select a material with a low dielectric loss tangent for the insulating layer to suppress this.

[0003] On the other hand, the insulating layer of high-frequency circuits is required to have a high dielectric constant for the insulating layer, as it is necessary for the formation of delay circuits, impedance matching of the wiring board in low-impedance circuits, miniaturization of wiring patterns, and the creation of composite circuits with capacitors built into the substrate itself. For this reason, electronic components using insulating layers with high dielectric constant and low dielectric loss tangent have been proposed (for example, Patent Document 1). High dielectric constant and low dielectric loss tangent insulating layers are formed by dispersing fillers such as ceramic powder and insulatingly treated metal powder in a resin.

[0004] Furthermore, with the miniaturization and increased density of printed circuit boards, there is a growing effort to thin the laminates used in printed circuit boards. This thinning also necessitates a thinner insulating layer. In this process, holes to ensure conductivity between insulating layers are generally created using laser processing. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2000-91717 [Overview of the project] [Problems that the invention aims to solve]

[0006] Generally, increasing the relative permittivity of an insulating layer requires incorporating fillers with high relative permittivity, but this also increases the dielectric loss tangent, leading to a problem of increased transmission loss of high-frequency signals. Therefore, there is a need for materials that maintain a high relative permittivity while simultaneously having a lower dielectric loss tangent.

[0007] Furthermore, in fillers used to manufacture insulating layers with high dielectric constant and low dielectric loss tangent, voids may be generated depending on the filler material used, which can cause delamination during the manufacturing of laminates. This can lead to problems such as deterioration of thermal properties (such as moisture absorption and heat resistance) and dielectric properties (high dielectric constant and low dielectric loss tangent) in printed circuit boards and the like.

[0008] Furthermore, when a substrate with a laminated resin layer containing dielectric powder is drilled using laser processing, the holes in the substrate are gouged out. Therefore, laser processing of a substrate with a laminated resin layer containing dielectric powder results in a problem of low insulation reliability between the holes.

[0009] Furthermore, when forming a metal foil laminate for the insulating layer, sufficient metal foil peel strength (for example, copper foil peel strength) is required.

[0010] The present invention has been made to solve the above-mentioned problems, and aims to provide a resin composition suitable for use in manufacturing an insulating layer of a printed circuit board, which has a high dielectric constant and a low dielectric loss tangent, excellent thermal properties, excellent laser processability, and high metal foil peel strength, as well as a cured product, prepreg, resin sheet, laminate, metal foil-clad laminate, and printed circuit board obtained using the resin composition. [Means for solving the problem]

[0011] The inventors of the present invention diligently studied to solve the above-mentioned problems of the prior art and, as a result, discovered that a specific resin composition can solve the aforementioned problems, thus completing the present invention.

[0012] In other words, the present invention is as follows. [1] A resin composition comprising a dielectric powder (A) having a relative permittivity of 12.0 or more at a frequency of 10 GHz as measured by the cavity resonator perturbation method, an inorganic filler (B) different from the dielectric powder (A) having an absorbance of 0.70 or more at a wavelength of 9.3 μm in the infrared absorption spectrum obtained using Fourier transform infrared spectroscopy, a melting point of 1600°C or less, and a thermosetting resin (C).

[0013] [2] The resin composition according to [1], wherein the mass ratio ((A):(B)) of the dielectric powder (A) to the inorganic filler (B) is 300:10 to 300:150.

[0014] [3] The resin composition according to [1] or [2], wherein the dielectric loss tangent of the dielectric powder (A) at a frequency of 10 GHz, measured according to the cavity resonator perturbation method, is 0.015 or less.

[0015] [4] The resin composition according to any one of [1] to [3], wherein the dielectric powder (A) comprises a titanium-based inorganic filler.

[0016] [5] The resin composition according to [4], wherein the titanium-based inorganic filler comprises at least one selected from the group consisting of uncoated titanium-based inorganic fillers and coated titanium-based inorganic fillers.

[0017] [6] The resin composition according to [5], wherein the surface-uncoated titanium-based inorganic filler comprises at least one selected from the group consisting of titanium monoxide, titanium dioxide, titanium trioxide, potassium titanate, calcium titanate, strontium titanate, barium titanate, aluminum titanate, and lead titanate.

[0018] [7] The resin composition according to [5] or [6], wherein the surface-coated titanium-based inorganic filler comprises surface-coated titanium oxide.

[0019] [8] The resin composition according to [7], wherein the surface-coated titanium oxide has an organic layer and / or an inorganic oxide layer on the surface of the titanium oxide particles.

[0020] [9] The resin composition according to any one of [1] to [8], wherein the inorganic filler (B) comprises an alkaline earth metal silicate.

[0021]

[10] The resin composition according to [9], wherein the alkaline earth metal silicate comprises an alkaline earth metal silicate having the structure Mg2Si2O6.

[0022]

[11] The resin composition according to [9] or

[10] , wherein the alkaline earth metal silicate comprises calcined talc.

[0023]

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

[11] , wherein the average particle size (D50) of the dielectric powder (A) is 0.10 μm or more and 10.00 μm or less, and the average particle size (D50) of the inorganic filler (B) is 0.10 μm or more and 10.00 μm or less.

[0024]

[13] The resin composition according to any one of [1] to

[12] , wherein the content of the dielectric powder (A) is 50 parts by mass or more and 500 parts by mass or less with respect to 100 parts by mass of the total resin solids in the resin composition.

[0025]

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

[13] , wherein the amount of the inorganic filler (B) is 10 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the total resin solids in the resin composition.

[0026]

[15] The thermosetting resin (C) contains at least one selected from the group consisting of a maleimide compound, a cyanate ester compound, an epoxy compound, a phenol compound, a modified polyphenylene ether compound, an alkenyl-substituted nadimide compound, an oxetane resin, a benzoxazine compound, and a compound having a polymerizable unsaturated group, and is the resin composition according to any one of [1] to

[14] .

[0027] <00002​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​(In formula (3), Ra independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. q is an integer from 0 to 4. If q is an integer from 2 to 4, Ra may be the same or different within the same ring. Rb independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. r is an integer from 0 to 3. If r is 2 or 3, Rb may be the same or different within the same ring. n3 is the average value, representing a value from 0.95 to 10.0.)

[0034] [ka]

[0035] (In formula (4), R1 independently represents an alkyl group having 1 to 10 carbon atoms. s represents an integer from 1 to 3. R2 independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group, halogen atom, hydroxyl group, or mercapto group having 3 to 10 carbon atoms. t represents an integer from 0 to 4. R3 independently represents a group represented by the following formula (5). u represents an integer from 0 to 2. R4 represents a hydrogen atom or a group represented by the following formula (5). R5 represents a hydrogen atom or a group represented by the following formula (6). n4 represents an integer from 1 to 100.)

[0036] [ka]

[0037] (In formula (5), R6 independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. v represents an integer from 0 to 4. *1 indicates a bonding site with a carbon atom.)

[0038] [ka]

[0039] (In formula (6), R7 independently represents an alkyl group having 1 to 10 carbon atoms. w represents an integer from 1 to 3. R8 independently represents the group represented by formula (5). x represents an integer from 0 to 2. *2 indicates the bonding site with a carbon atom.)

[0040]

[17] The resin composition according to

[15] or

[16] , wherein the cyanate ester compound comprises one or more selected from the group consisting of phenol novolac type cyanate ester compounds, naphthol aralkyl type cyanate ester compounds, naphthylene ether type cyanate ester compounds, xylene resin type cyanate ester compounds, bisphenol M type cyanate ester compounds, bisphenol A type cyanate ester compounds, diallylbisphenol A type cyanate ester compounds, bisphenol E type cyanate ester compounds, bisphenol F type cyanate ester compounds, and biphenyl aralkyl type cyanate ester compounds, and prepolymers or polymers of these cyanate ester compounds.

[0041]

[18] The resin composition according to any one of

[15] to

[17] , wherein the epoxy compound comprises one or more selected from the group consisting of biphenylaralkyl epoxy resins, naphthalene epoxy resins, naphthylene ether epoxy resins, and butadiene skeleton-containing epoxy resins.

[0042]

[19] A resin composition according to any of [1] to

[18] , for use in printed circuit boards.

[0043] A cured product comprising the resin composition described in any of

[20] [1] to

[19] .

[0044]

[21] A prepreg comprising a substrate and a resin composition according to any one of [1] to

[19] impregnated or coated onto the substrate.

[0045] A resin sheet comprising the resin composition described in any of

[22] [1] to

[19] .

[0046] Laminates including the prepregs described in

[23]

[21] .

[0047] A laminated board containing the resin sheet described in

[24] and

[22] .

[0048] A metal foil-clad laminate comprising a laminate described in

[25]

[23] and a metal foil arranged on one or both sides of the laminate.

[0049] A metal foil-clad laminate comprising a laminate described in

[26]

[24] and a metal foil disposed on one or both sides of the laminate.

[0050]

[27] A printed circuit board having an insulating layer and a conductive layer disposed on one or both sides of the insulating layer, wherein the insulating layer contains a cured product of any of the resin compositions described in [1] to

[19] . [Effects of the Invention]

[0051] The present invention provides a resin composition suitable for manufacturing an insulating layer of a printed circuit board, having a high dielectric constant and low dielectric loss tangent, excellent thermal properties, excellent laser processability, and high metal foil peel strength, as well as cured products, prepregs, resin sheets, laminates, metal foil-clad laminates, and printed circuit boards obtained using the resin composition. [Brief explanation of the drawing]

[0052] [Figure 1]Figure 1 shows the infrared absorption spectrum obtained using the KBr tablet method of Fourier transform infrared spectroscopy. [Figure 2] Figure 2 shows the X-ray diffraction pattern of calcined talc. [Figure 3] Figure 3 shows the X-ray diffraction pattern of fine talc powder. [Modes for carrying out the invention]

[0053] The following describes in detail embodiments for carrying out the present invention (hereinafter referred to as "this embodiment"). This embodiment is illustrative for explaining the present invention and is not intended to limit the present invention to the following content. The present invention can be implemented by modifying it as appropriate within the scope of its gist.

[0054] In this embodiment, unless otherwise specified, "resin solids" or "resin solids in the resin composition" refers to the resin components in the resin composition excluding dielectric powder (A), inorganic filler (B), other fillers, additives (silane coupling agents, wetting and dispersing agents, curing accelerators, and other components), and solvents. "100 parts by mass of resin solids" or "100 parts by mass of total resin solids in the resin composition" means that the total amount of resin components in the resin composition excluding dielectric powder (A), inorganic filler (B), other fillers, additives (silane coupling agents, wetting and dispersing agents, curing accelerators, and other components), and solvents is 100 parts by mass.

[0055] [Resin composition] The resin composition of this embodiment comprises a dielectric powder (A) (hereinafter also simply referred to as "dielectric powder (A)") having a relative permittivity of 12.0 or more at a frequency of 10 GHz as measured by the cavity resonator perturbation method, an inorganic filler (B) (hereinafter also simply referred to as "inorganic filler (B)") which is different from dielectric powder (A) and has an absorbance of 0.70 or more at a wavelength of 9.3 μm in the infrared absorption spectrum obtained using Fourier transform infrared spectroscopy, a melting point of 1600°C or less, and a thermosetting resin (C).

[0056] By using the resin composition of this embodiment, cured products, prepregs, resin sheets, laminates, metal foil-clad laminates, and printed circuit boards can be suitably manufactured, possessing high dielectric constant and low dielectric loss tangent, excellent thermal properties such as moisture absorption and heat resistance, excellent laser processability, and high metal foil peel strength. The resin composition of this embodiment is suitably used in the manufacture of the insulating layer of printed circuit boards.

[0057] The inventors have found that by using a resin composition containing a specific dielectric powder (A), a specific inorganic filler (B), and a thermosetting resin (C) as the insulating layer of a printed circuit board, the substrate on which the insulating layer is laminated is less susceptible to gouging of the hole walls during laser drilling. Therefore, according to this embodiment, it is possible to obtain a cured product with high dielectric constant and low dielectric loss tangent, excellent thermal properties such as moisture absorption and heat resistance, and high metal foil peel strength, while also having excellent laser processability. The reason for this is not entirely clear, but the inventors deduce it as follows.

[0058] In other words, while drilling holes in printed circuit boards is typically performed using carbon dioxide (CO2) lasers, mechanical drills, ultraviolet (UV) lasers, and YAG lasers, carbon dioxide lasers are preferred because they allow for precise processing of small-diameter holes and offer superior processing speed and cost-effectiveness. However, when drilling holes using a carbon dioxide laser, if the insulating layer is formed from a resin composition containing an inorganic filler (B) with a relatively high melting point, drilling the insulating layer by the heat of the carbon dioxide laser tends to be difficult. Furthermore, if the inorganic filler (B) has low absorbance at 9.3 μm, one of the wavelengths of the carbon dioxide laser, the energy of the carbon dioxide laser light is less easily converted into heat, requiring a larger amount of energy for drilling. As a result, the amount of heat required for drilling increases, causing heat to propagate not only in the laser irradiation direction but also horizontally. Consequently, the hole walls of the substrate become more susceptible to gouging, leading to a problem of reduced insulation reliability between hole walls. Furthermore, the gouging of the hole walls in the substrate leads to problems such as reduced thermal properties of the resin layer, including moisture absorption and heat resistance, as well as reduced metal foil peel strength.

[0059] On the other hand, the resin composition of this embodiment includes a thermosetting resin (C), a specific dielectric powder (A), and a specific inorganic filler (B). The inorganic filler (B) has a relatively low melting point. Therefore, the insulating layer formed from the resin composition containing the inorganic filler (B) can be easily drilled by the heat of a carbon dioxide laser, even if it contains dielectric powder (A) and other fillers as needed. Furthermore, the inorganic filler (B) has a high absorbance at a wavelength of 9.3 μm. As a result, the energy of the carbon dioxide laser light can be efficiently converted into heat in the insulating layer, reducing the amount of energy required for drilling and thus reducing the amount of heat. As a result, heat propagation in the horizontal direction is reduced, and heat can be efficiently propagated in the direction of laser irradiation. This suppresses gouging of the hole walls of the substrate and improves the insulation reliability between hole walls.

[0060] Furthermore, since the heat from the carbon dioxide laser does not propagate excessively to the dielectric powder (A), the dielectric powder (A) is no longer at risk of being decomposed by irradiation with the carbon dioxide laser. In addition, since gouging of the hole walls of the substrate is suppressed, the dielectric powder (A) is less likely to be exposed through the gouging. As a result, the insulating layer can suitably possess the high dielectric constant and low dielectric loss tangent exhibited by the dielectric powder (A).

[0061] Furthermore, because gouging of the hole walls of the substrate is suppressed, the resin layer can have excellent thermal properties such as moisture absorption and heat resistance, as well as high metal foil peel strength.

[0062] Therefore, the present inventors estimate that, according to this embodiment, it is possible to obtain a cured product with excellent laser processability while possessing a high dielectric constant and low dielectric loss tangent, excellent thermal properties such as moisture absorption and heat resistance, and high metal foil peel strength. However, the reasons are not limited to this.

[0063] Next, each component included in the resin composition of this embodiment will be described in detail.

[0064] [Dielectric powder (A)] The resin composition of this embodiment includes dielectric powder (A) having a relative permittivity (Dk) of 12.0 or higher at a frequency of 10 GHz, as measured according to the cavity resonator perturbation method. Dielectric powder (A) may be used alone or in combination of two or more types.

[0065] The relative permittivity of dielectric powder (A) is the value measured at a frequency of 10 GHz by the cavity resonator perturbation method. The relative permittivity of dielectric powder (A) can be calculated using the Bruggeman formula (compound rule). The relative permittivity can be measured, for example, as follows: Dielectric powder (A) is packed into a PTFE (polytetrafluoroethylene) tube (inner diameter: 1.5 mm), and the relative permittivity of dielectric powder (A) at a frequency of 10 GHz is measured using a network analyzer. Similarly, the relative permittivity of the PTFE tube at a frequency of 10 GHz is measured using a network analyzer. The relative permittivity of dielectric powder (A) can be calculated from these measured values ​​using the Bruggeman formula (compound rule). The relative permittivity is measured under conditions of 23°C ± 1°C and 50% RH (relative humidity) ± 5% RH. The specific method for measuring the relative permittivity is as described in the examples.

[0066] The relative permittivity of the dielectric powder (A) is preferably 13.0 or higher, and more preferably 15.0 or higher. When the relative permittivity is 13.0 or higher, an insulating layer with a higher relative permittivity tends to be obtained. The upper limit of the relative permittivity is not particularly limited, but for example, it is 100.0 or lower. The upper limit of the relative permittivity may be 90.0 or lower, 80.0 or lower, 70.0 or lower, 60.0 or lower, 50.0 or lower, 40.0 or lower, or 30.0 or lower.

[0067] The dielectric loss tangent (Df) of the dielectric powder (A) at a frequency of 10 GHz, measured according to the cavity resonator perturbation method, is preferably 0.015 or less, more preferably 0.010 or less, and even more preferably 0.008 or less. When the dielectric loss tangent is 0.015 or less, an insulating layer with an even lower dielectric loss tangent tends to be obtained. The lower limit of the dielectric loss tangent is not particularly limited, but for example, it is 0.001 or more.

[0068] The dielectric loss tangent of dielectric powder (A) can be measured and calculated using the same method as the relative permittivity of dielectric powder (A) described above. The specific method for measuring the dielectric loss tangent is as described in the examples.

[0069] The average particle size (D50) of the dielectric powder (A) is preferably 0.10 μm to 10.00 μm, more preferably 0.15 μm to 8.00 μm, and even more preferably 0.20 μm to 7.50 μm, from the viewpoint of obtaining better dispersibility. In this specification, the average particle size (D50) refers to the value obtained when the particle size distribution of a predetermined amount of powder introduced into the dispersion medium is measured using a laser diffraction / scattering particle size distribution analyzer, and the volume integrated from the smallest particles reaches 50% of the total volume. The average particle size (D50) can be calculated by measuring the particle size distribution by the laser diffraction / scattering method, and the specific measurement method is as described in the examples.

[0070] The dielectric powder (A), in the infrared absorption spectrum obtained using the KBr tablet method of Fourier transform infrared spectroscopy, preferably has an absorbance of 0.70 or less, more preferably 0.60 or less, and even more preferably 0.50 or less at a wavelength of 9.3 μm. The lower limit of the absorbance is not particularly limited, but is 0.00 or higher. The specific method for measuring the absorbance is as described in the examples.

[0071] The melting point of dielectric powder (A) is preferably 1000°C or higher, more preferably 1000°C to 2500°C, even more preferably 1200°C to 2300°C, and even more preferably 1300°C to 2200°C. When the melting point is within the above range, it tends to yield a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards, which has a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as improved moisture absorption and heat resistance, and higher metal foil peel strength, while also having even better laser processability. The melting point of dielectric powder (A) can be measured, for example, by differential thermogravimetric analysis. The specific method for measuring the melting point is as described in the examples.

[0072] The shape of the dielectric powder (A) is not particularly limited and can be flaky, spherical, plate-like, or irregular. However, a spherical shape is preferable because it tends to disperse better with the thermosetting resin (C), have a higher dielectric constant and lower dielectric loss tangent, and yield resin compositions suitable for use in the manufacture of insulating layers for printed circuit boards, which have better thermal properties such as superior moisture absorption and heat resistance, superior laser processability, and higher metal foil peel strength.

[0073] (Titanium-based inorganic filler) The dielectric powder (A) preferably contains a titanium-based inorganic filler. The titanium-based inorganic filler preferably includes at least one selected from the group consisting of uncoated titanium-based inorganic fillers and coated titanium-based inorganic fillers. When the dielectric powder (A) contains these dielectric powders, it tends to yield a resin composition suitable for manufacturing the insulating layer of printed circuit boards, which has a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength.

[0074] (Uncoated titanium-based inorganic filler) Examples of uncoated titanium-based inorganic fillers include titanium monoxide (TiO), titanium dioxide (TiO2), titanium trioxide (Ti2O3), potassium titanate (e.g., K2Ti4O9), calcium titanate (e.g., CaTiO3), strontium titanate (e.g., SrTiO3), and barium titanate (e.g., BaTiO3). 3、 It is more preferable that the dielectric powder (A) contains at least one selected from the group consisting of (and BaTi4O9), aluminum titanate (e.g., Al2O3·TiO2), and lead titanate (e.g., PbTiO3). When the dielectric powder (A) contains these dielectric powders, it tends to yield a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards, which has an even higher dielectric constant and an even lower dielectric loss tangent, even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength.

[0075] As the surface-uncoated titanium-based inorganic filler, it is more preferable to contain at least one selected from the group consisting of calcium titanate, strontium titanate, and barium titanate, and it is even more preferable to contain strontium titanate. When the dielectric powder (A) contains these dielectric powders, it has an even higher dielectric constant and an even lower dielectric tangent, even more excellent thermal properties such as moisture absorption heat resistance, even more excellent laser processability, and even higher metal foil peel strength. Tend to obtain resin compositions and the like that are suitably used for the production of the insulating layer of a printed wiring board. Further, when the dielectric powder (A) contains strontium titanate, in addition to the above effects, it has a lower catalytic activity with respect to the thermosetting resin (C) and tends to have more excellent moldability.

[0076] As strontium titanate, known ones can be used. For example, oxides having a perovskite structure mainly represented by ABO3 can be mentioned. Strontium titanate may contain a compound having a structure represented by (SrO) X ·TiO2 (0.9 ≦ x < 1.0, 1.0 < x ≦ 1.1). In this compound, a part of Sr may be substituted with another metal element. Examples of such a metal element include at least one of La (lanthanum), Ba (barium), and Ca (calcium). Further, in this compound, a part of Ti may be substituted with another metal element. Examples of such a metal element include Zr (zirconium).

[0077] As barium titanate, known ones can be used. For example, oxides having a perovskite structure mainly represented by ABO3 can be mentioned. Barium titanate contains Ba m TiO 2+mThe compounds may include those having a structure represented by (0.995 ≤ m ≤ 1.010, 0.995 ≤ Ba / Ti (molar ratio) ≤ 1.010). Another example of barium titanate is a compound having a structure represented by BaTi4O9. In these compounds, part of the Ba may be substituted with another metal element, such as at least one of La (lanthanum), Sr (strontium), and Ca (calcium). In this compound, part of the Ti may also be substituted with another metal element, such as Zr (zirconium).

[0078] As calcium titanate, known types can be used, for example, perovskite oxides mainly represented by ABO3. Calcium titanate contains Ca m TiO 2+m The compound may contain a structure represented by (0.995 ≤ m ≤ 1.010, 0.995 ≤ Ca / Ti (molar ratio) ≤ 1.010). In this compound, some of the Ca may be substituted with another metal element, for example, at least one of La (lanthanum), Sr (strontium), and Ca (calcium). In this compound, some of the Ti may also be substituted with another metal element, for example, Zr (zirconium).

[0079] Titanium dioxide having a rutile or anatase crystal structure is preferred, and a rutile crystal structure is more preferred.

[0080] Commercially available titanium-based inorganic fillers can be used as uncoated surface fillers. Examples of commercially available titanium dioxide include STT-30A and EC-300 from Titanium Industries Co., Ltd., and AEROXIDE (registered trademark, hereinafter the same) TiO2T805 and AEROXIDE from Nippon Aerosil Co., Ltd. Examples of products include TiO2NKT90 (trade name); barium titanate such as BT-149 (trade name) manufactured by Nippon Chemical Industrial Co., Ltd., and 208108 (trade name) manufactured by ALDRICH Corporation; calcium titanate such as the CT series manufactured by Fuji Titanium Industries Co., Ltd., and spherical calcium titanate manufactured by Denka Co., Ltd. (trade name); strontium titanate such as ST-2 manufactured by Kyoritsu Material Co., Ltd., ST-03 manufactured by Sakai Chemical Industry Co., Ltd., 396141 manufactured by ALDRICH Corporation, ST, HST-1, HPST-1, and HPST-2 manufactured by Fuji Titanium Industries Co., Ltd., and SW-100, SW-50C, SW-100C, SW-200C, SW-320C, and SW-350 manufactured by Titanium Industries Co., Ltd. (trade name); and titanium trioxide such as STR-100A-LP manufactured by Sakai Chemical Industry Co., Ltd., and MT-N1 manufactured by Teika Co., Ltd. (trade name).

[0081] (Surface coating titanium-based inorganic filler) The surface-coated titanium-based inorganic filler preferably has an organic layer and / or an inorganic oxide layer on the surface of the titanium-based inorganic filler that forms the core of the surface-coated titanium-based inorganic filler. The surface-coated titanium-based inorganic filler may be used alone, or in combination of two or more types of surface-coated titanium-based inorganic fillers with different particle sizes and surface conditions.

[0082] Examples of core titanium-based inorganic fillers include the above-mentioned uncoated titanium-based inorganic fillers.

[0083] For the organic layer and inorganic oxide layer, refer to the organic layer and inorganic oxide layer described in the section on surface-coated titanium oxide below.

[0084] The average particle size (D50) of the core titanium-based inorganic filler is preferably 0.10 μm to 10.00 μm, more preferably 0.15 μm to 8.00 μm, and even more preferably 0.20 μm to 7.50 μm, from the viewpoint of dispersibility. The average particle size (D50) of the titanium-based inorganic filler is determined from the average value of the particle sizes of primary particles made up of a single particle.

[0085] <Surface-coated titanium oxide> The surface-coated titanium-based inorganic filler preferably contains surface-coated titanium oxide. Surface-coated titanium oxide preferably has an organic layer and / or an inorganic oxide layer on the surface of titanium oxide particles that form the core of the surface-coated titanium oxide (hereinafter simply referred to as "titanium oxide particles" or "core particles"). Surface-coated titanium oxide may be used alone or in combination of two or more types of surface-coated titanium oxide with different particle sizes and surface conditions.

[0086] The total amount of the organic layer and inorganic oxide layer in the surface-coated titanium oxide (coating amount) is preferably 0.1% to 10.0% by mass, more preferably 1.0% to 8.0% by mass, and even more preferably 1.0% to 4.0% by mass, relative to 100% by mass of the surface-coated titanium oxide. When the coating amount is within the above range, it tends to yield resin compositions suitable for use in the manufacture of insulating layers for printed circuit boards, which have a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength.

[0087] The titanium dioxide content in the surface-coated titanium dioxide is preferably 90.0% to 99.9% by mass, more preferably 92.0% to 99.0% by mass, and even more preferably 96.0% to 99.0% by mass, based on 100% by mass of the surface-coated titanium dioxide. When the content is within the above range, it tends to yield a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards, which has a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength.

[0088] Examples of core particles include titanium monoxide (TiO), dititanium trioxide (Ti2O3), and titanium dioxide (TiO2). Among these, titanium dioxide is preferred. Titanium dioxide having a rutile or anatase crystal structure is preferred, with a rutile crystal structure being more preferred.

[0089] The average particle size (D50) of the core particles is preferably 0.10 μm or more and 0.45 μm or less, and more preferably 0.15 μm or more and 0.25 μm or less, from the viewpoint of dispersibility. The average particle size (D50) of the core particles is determined from the average value of the particle sizes of primary particles by a single particle.

[0090] Surface-coated titanium oxide is typically obtained by coating the surface of core particles with an organic layer or an inorganic oxide layer using a surface treatment agent. Furthermore, the surface of the organic layer or inorganic oxide layer coated on the core particles may be further coated with an organic layer and / or an inorganic oxide layer using a surface treatment agent. Since resin compositions suitable for manufacturing insulating layers of printed circuit boards tend to be obtained that have a higher dielectric constant and a lower dielectric loss tangent, superior thermal properties such as moisture absorption and heat resistance, superior laser processability, and higher metal foil peel strength, it is preferable that surface-coated titanium oxide further has an organic layer on the surface of the inorganic oxide layer coated on the core particles. Coating methods include inorganic treatment and organic treatment. The surface treatment agent may be used individually or in combination of two or more types.

[0091] Examples of surface treatment agents used in inorganic treatment include oxoacids (e.g., silicic acid and aluminic acid), metal salts of oxoacids (e.g., sodium silicate and sodium aluminate), oxides, hydroxides, and hydrated oxides of metals such as aluminum, silicon, zirconium, tin, titanium, antimony, zinc, cobalt, and manganese. Surface-coated titanium oxide obtained by inorganic treatment has an inorganic oxide layer on the surface of titanium oxide particles, on the surface of the inorganic oxide layer, or on the surface of the organic layer described later.

[0092] Examples of surface treatment agents used in organic treatment include organosilicon compounds such as organosilanes, silane coupling agents, and organopolysiloxanes; organotitanium compounds such as titanium coupling agents; and organic substances such as organic acids, polyols, and alkanolamines. Surface-coated titanium oxide obtained by organic treatment has an organic layer on the surface of titanium oxide particles, on the surface of the organic layer, or on the surface of the inorganic oxide layer.

[0093] Examples of organosilanes include n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, 3-chloropropyltriethoxysilane, phenyltriethoxysilane, and trifluoropropyltrimethoxysilane, among other alkoxysilanes.

[0094] Examples of silane coupling agents include aminosilanes such as 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane; epoxysilanes such as 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; methacrylsilanes such as 3-(methacryloyloxypropyl)trimethoxysilane; vinylsilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltrichlorosilane; and mercaptosilanes such as 3-mercaptopropyltrimethoxysilane.

[0095] As the organopolysiloxane, silicone oil is preferred because it allows for the formation of a more uniform organic layer. Examples of silicone oils include alkyl silicones, alkyl hydrogen silicones, alkoxy silicones, and modified silicones. Examples of alkyl silicones include dimethyl silicone. Examples of alkyl hydrogen silicones include methyl hydrogen silicone and ethyl hydrogen silicone. Preferred alkoxysilicones include silicone compounds containing alkoxysilyl groups in which the alkoxy group is directly bonded to a silicon atom or via a divalent hydrocarbon group. Examples of such silicone compounds include linear, cyclic, network, and partially branched linear organopolysiloxanes. Among these, linear organopolysiloxanes are preferred, and organopolysiloxanes having a molecular structure in which the alkoxy group is directly bonded to the silicone main chain are more preferred. Examples of alkoxysilicones include methoxysilicones and ethoxysilicones. Examples of modified silicones include amino-modified silicones, epoxy-modified silicones, and mercapto-modified silicones.

[0096] Examples of titanium coupling agents include isopropyltriisostearoyl titanate, isopropyldimethacrylateisostearoyl titanate, and isopropyltridodecylbenzenesulfonyl titanate.

[0097] Examples of organic acids include adipic acid, terephthalic acid, lauric acid, myristic acid, palmitic acid, stearic acid, polyhydroxystearic acid, oleic acid, salicylic acid, malic acid, and maleic acid, as well as their metal salts.

[0098] Examples of polyols include trimethylolethane, trimethylolpropane, ditrimethylolpropane, trimethylolpropane ethoxylate, and pentaerythritol.

[0099] Examples of alkanolamines include monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine, triethanolamine, and trippropanolamine.

[0100] A resin composition is obtained that has good dispersibility with thermosetting resin (C), exhibits even better thermal properties such as moisture absorption and heat resistance during curing, and has superior dielectric properties (high dielectric constant and low dielectric loss tangent). Furthermore, an insulating layer with more suitable surface hardness is obtained. Therefore, as the surface-coated titanium oxide, it is preferable that the titanium oxide particles have an inorganic oxide layer on their surface, and the inorganic oxide layer is one or more selected from the group consisting of a layer containing silica, a layer containing zirconia, and a layer containing alumina, and it is more preferable that the inorganic oxide layer is one or more selected from the group consisting of a layer containing silica and a layer containing alumina. When such surface-coated titanium oxide is used, a resin composition is obtained that is better compatible with thermosetting resin (C), has a higher dielectric constant and a lower dielectric loss tangent, exhibits superior thermal properties such as moisture absorption and heat resistance, superior laser processability, and higher metal foil peel strength, making it suitable for use in the manufacture of insulating layers for printed circuit boards.

[0101] The surface-coated titanium oxide may have two or more inorganic oxide layers. When there are two or more inorganic oxide layers, it is preferable that the inorganic oxide layer located closer to the titanium oxide particles can further suppress water absorption by the titanium oxide particles, which are the core particles, and the inorganic oxide layer located further away from the titanium oxide particles can further improve adhesion to the resin component, relaxation of aggregation of the surface-coated titanium oxide in the resin composition, and dispersibility. From this perspective, when the surface-coated titanium oxide has two or more inorganic oxide layers, it is preferable that the inorganic oxide layer located closer to the core particles is one or more selected from the group consisting of a silica-containing layer and a zirconia-containing layer, and that the inorganic oxide layer located further away from the core particles is an alumina-containing layer, and more preferably that the inorganic oxide layer located closer to the core particles is a silica-containing layer and the inorganic oxide layer located further away from the core particles is an alumina-containing layer.

[0102] The inorganic oxide layer content is preferably 0.1% to 10.0% by mass, more preferably 0.3% to 7.5% by mass, even more preferably 0.4% to 5.0% by mass, even more preferably 0.5% to 4.0% by mass, and even more preferably 0.5% to 3.3% by mass, based on 100% by mass of surface-coated titanium oxide. When the content is within the above range, it tends to yield resin compositions suitable for use in manufacturing insulating layers of printed circuit boards, which have a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength.

[0103] The inorganic oxide layer has the effect of suppressing water absorption by the core particles, titanium oxide. On the other hand, silica, zirconia, and alumina, which are inorganic oxides that make up the inorganic oxide layer, are hydrated inorganic substances, and therefore have a relatively high water absorption rate among inorganic oxides, and tend to evaporate moisture easily during reflow soldering. Evaporated moisture causes void formation in the insulating layer. For these reasons, it is preferable that the surface-coated titanium oxide has an organic layer on the surface of the inorganic oxide layer. The organic layer further reduces the water absorption of the core particles, titanium oxide and the inorganic oxide layer, and can further suppress the water absorption of the resin composition. Therefore, it is possible to suppress the evaporation of moisture from the insulating layer during reflow soldering. In addition, the organic layer also has the effect of further mitigating the aggregation of surface-coated titanium oxide in the resin composition and further improving dispersibility.

[0104] As for the organic layer, it is preferable that the layer is surface-treated with an organosilicon compound, as this can further alleviate the aggregation of titanium oxide surface coatings in the resin composition, further improve dispersibility, and reduce the water absorption rate of the laminate due to superior water repellency. The organosilicon compound preferably includes one or more selected from the group consisting of silane coupling agents, organosilanes, and organopolysiloxanes. By surface treatment using these surface treatment agents, the resulting organic layer has a siloxane structure. Layers with a siloxane structure can further alleviate the aggregation of surface-coating titanium oxide in the resin composition, further improve dispersibility, and tend to reduce the water absorption rate of the laminate due to superior water repellency. Furthermore, as the organopolysiloxane, silicone oil is preferred because it can form a layer with a more uniform siloxane structure and further enhances the above-mentioned effects, and dimethyl silicone is more preferred among silicone oils. In this case, other surface treatment agents may be used as long as the organic layer has a siloxane structure.

[0105] Since aggregation of surface-coated titanium oxide in the resin composition can be further reduced and dispersibility can be further improved, the total amount of the organic layer is preferably 0.1% to 10.0% by mass, more preferably 0.5% to 7.5% by mass, even more preferably 0.6% to 6.0% by mass, even more preferably 0.7% to 5.0% by mass, and even more preferably 0.7% to 3.5% by mass, based on 100% by mass of surface-coated titanium oxide.

[0106] When the surface-coated titanium oxide has an inorganic oxide layer and an organic layer, the coating layer of the surface-coated titanium oxide may have a two-layer structure consisting of an inorganic oxide layer and an organic layer. This layer structure suppresses the catalytic activity of titanium oxide (e.g., photocatalytic activity and metal catalytic activity) and provides water-repellent effects. In this case, the inorganic oxide layer is preferably one or more selected from the group consisting of a layer containing silica, a layer containing zirconia, and a layer containing alumina, and a layer containing alumina is more preferable because it can further suppress the catalytic activity of titanium oxide while further increasing its affinity with the resin. The organic layer is preferably siloxane in structure because it has excellent heat resistance and chemical stability. By using such surface-coated titanium oxide, the water absorption of titanium oxide can be further suppressed, adhesion with resin components can be further improved, and aggregation of surface-coated titanium oxide in the resin composition can be further reduced. As a result, resin compositions that are better compatible with thermosetting resin (C), have a higher dielectric constant and a lower dielectric loss tangent, and tend to have better thermal properties such as superior moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength, are suitable for use in the manufacture of insulating layers for printed circuit boards. Commercially available titanium oxide can be used as the surface coating material. Examples of commercially available products include R-22L and R-11P (both trade names, manufactured by Sakai Chemical Industry Co., Ltd.).

[0107] When the surface-coated titanium oxide has an inorganic oxide layer and an organic layer, it is preferable that the inorganic oxide layer located closer to the core particles is a silica-containing layer, the next inorganic oxide layer is an alumina-containing layer, and the organic layer located furthest from the core particles is a siloxane-containing layer. Using such surface-coated titanium oxide tends to yield resin compositions that are better compatible with thermosetting resins (C), have a higher dielectric constant and a lower dielectric loss tangent, possess superior thermal properties such as moisture absorption and heat resistance, superior laser processability, and higher metal foil peel strength, making them suitable for use in the manufacture of insulating layers for printed circuit boards. Commercially available titanium oxide can be used as the surface coating material. An example of a commercially available product is CR-63 (product name, Ishihara Sangyo Co., Ltd.).

[0108] The mass ratio of dielectric powder (A) to inorganic filler (B) (dielectric powder (A):inorganic filler (B)) is preferably 300:10 to 300:150, more preferably 300:15 to 300:125, even more preferably 300:20 to 300:110, even more preferably 300:31 to 300:107, even more preferably 300:35 to 300:105, and even more preferably 300:40 to 300:100. When the mass ratio is within the above range, it tends to yield resin compositions suitable for use in manufacturing insulating layers of printed circuit boards, which have a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength.

[0109] The content of the dielectric powder (A) is preferably 50 to 500 parts by mass, more preferably 60 to 450 parts by mass, and still more preferably 70 to 400 parts by mass with respect to 100 parts by mass in total of the resin solids in the resin composition. When the content is within the above range, a resin composition and the like that are preferably used for manufacturing an insulating layer of a printed wiring board, having a higher dielectric constant and a lower dielectric loss tangent, more excellent thermal properties such as moisture absorption and heat resistance, more excellent laser processability, and a higher metal foil peel strength tend to be obtained. When the resin composition contains two or more kinds of dielectric powders (A), it is preferable that the total amount thereof is within the above range.

[0110] [Inorganic filler (B)] The resin composition of the present embodiment contains an inorganic filler (B) having an absorbance of 0.70 or more at a wavelength of 9.3 μm and a melting point of 1600° C. or less in an infrared absorption spectrum obtained using Fourier transform infrared spectroscopy. The inorganic filler (B) is different from the dielectric powder (A). The inorganic filler (B) may be used alone or in combination of two or more kinds.

[0111] The absorbance of the inorganic filler (B) is a value at a wavelength of 9.3 μm (wave number: 1075 cm -1 ) in an infrared absorption spectrum obtained using the KBr tablet method of Fourier transform infrared spectroscopy. The specific measurement method of the absorbance is as described in the examples.

[0112] The absorbance of the inorganic filler (B) is preferably 0.72 or more, and more preferably 0.75 or more. When the absorbance is within the above range, a resin composition and the like that are preferably used for manufacturing an insulating layer of a printed wiring board, having a higher dielectric constant and a lower dielectric loss tangent, more excellent thermal properties such as moisture absorption and heat resistance, a higher metal foil peel strength, and further excellent laser processability tend to be obtained. The upper limit of the absorbance is not particularly limited, but is, for example, 1.00 or less.

[0113] The melting point of the inorganic filler (B) can be measured, for example, by differential thermogravimetric analysis. The specific method for measuring the melting point is as described in the examples.

[0114] The melting point of the inorganic filler (B) is preferably 1580°C or lower, and more preferably 1560°C or lower. When the melting point is within the above range, it tends to yield a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards, which has a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as improved moisture absorption and heat resistance, and higher metal foil peel strength, while also having even better laser processability. The lower limit of the melting point is not particularly limited, but for example, it is 800°C or higher. The lower limit may be 1000°C or higher.

[0115] The relative permittivity (Dk) of the inorganic filler (B) at a frequency of 10 GHz, measured according to the cavity resonator perturbation method, is preferably less than 12.0, more preferably 10.0 or less, even more preferably 8.0 or less, and even more preferably 7.0 or less. The lower limit of the relative permittivity is not particularly limited, but for example, it is 0.1 or more.

[0116] The dielectric loss tangent (Df) of the inorganic filler (B) at a frequency of 10 GHz, measured according to the cavity resonator perturbation method, is preferably 0.015 or less, more preferably 0.010 or less, and even more preferably 0.008 or less. When the dielectric loss tangent is 0.015 or less, an insulating layer with an even lower dielectric loss tangent tends to be obtained. The lower limit of the dielectric loss tangent is not particularly limited, but for example, it is 0.001 or more.

[0117] The relative permittivity and dielectric loss tangent of the inorganic filler (B) can be measured and calculated using the same method as the relative permittivity of the dielectric powder (A) described above. The specific measurement methods for the relative permittivity and dielectric loss tangent are as described in the examples.

[0118] The average particle size (D50) of the inorganic filler (B) is preferably 0.10 μm or more and 10.00 μm or less, more preferably 0.30 μm or more and 8.00 μm or less, and even more preferably 1.00 μm or more and 7.00 μm or less. The average particle size (D50) of the inorganic filler (B) can be measured and calculated in the same manner as the average particle size (D50) of the dielectric powder (A) described above. The specific measurement method is as described in the examples.

[0119] The shape of the inorganic filler (B) is not particularly limited and can be flaky, spherical, plate-like, or irregular. A spherical shape is preferable because it tends to disperse better with the dielectric powder (A) and thermosetting resin (C), have a higher dielectric constant and a lower dielectric loss tangent, and yield resin compositions suitable for use in the manufacture of insulating layers for printed circuit boards, which have better thermal properties such as superior moisture absorption and heat resistance, superior laser processability, and higher metal foil peel strength.

[0120] The inorganic filler (B) preferably contains an alkaline earth metal silicate. When the inorganic filler (B) contains an alkaline earth metal silicate, it tends to yield a resin composition suitable for use in the manufacture of an insulating layer for printed circuit boards, which has a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength.

[0121] Examples of alkaline earth metal silicates include compounds containing calcium silicate, compounds containing magnesium silicate, and compounds containing barium silicate. These alkaline earth metal silicates may have different crystalline forms or be in hydrate form. Alkaline earth metal silicates may contain two or more alkaline earth metals, such as a complex of calcium and magnesium.

[0122] The alkaline earth metal silicate preferably contains a compound containing magnesium silicate, and more preferably contains calcined talc.

[0123] Alkaline earth metal silicates preferably include alkaline earth metal silicates having the structure Mg2Si2O6. Alkaline earth metal silicates having the structure Mg2Si2O6 include, for example, enstatite and clinoenstatite.

[0124] Calcined talc can usually be obtained by heat-treating raw talc, for example, at a temperature of 900°C to 1500°C for 4 to 10 hours, and then calcining it. Examples of raw talc include Mg3Si4O 10 Examples include hydrated magnesium silicate, such as compounds having the (OH)2 structure. The raw material talc can be in the form of fine powder or fine powder. When the raw material talc is in powder form, its average particle size (D50) is usually between 1.0 μm and 7.0 μm. Calcined talc is an alkaline earth metal silicate having the structure Mg2Si2O6.

[0125] Commercially available calcined talc can be used. Examples of commercially available products include BST-200L, CHT-125, ST-95, ST-100, and ST-2000 (all product names from Nippon Talc Co., Ltd.), MS310 (product name from Fuji Talc Industry Co., Ltd.), and Crown Talc® PP (product name from Matsumura Sangyo Co., Ltd.).

[0126] The content of inorganic filler (B) is preferably 10 to 200 parts by mass, more preferably 15 to 150 parts by mass, even more preferably 20 to 125 parts by mass, even more preferably 40 to 110 parts by mass, and even more preferably 30 to 100 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. When the content is within the above range, it tends to yield a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards, which has a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength. When the resin composition contains two or more types of inorganic filler (B), it is preferable that their total amount is within the above range.

[0127] [Thermosetting resin (C)] The resin composition of this embodiment includes a thermosetting resin (C). The thermosetting resin (C) is not particularly limited as long as it is a thermosetting resin or compound. The thermosetting resin (C) may be used alone or in combination of two or more types.

[0128] The thermosetting resin (C) preferably contains one or more selected from the group consisting of maleimide compounds, cyanate ester compounds, epoxy compounds, phenol compounds, modified polyphenylene ether compounds, alkenyl-substituted nadiimide compounds, oxetane resins, benzoxazine compounds, and compounds having polymerizable unsaturated groups; more preferably contains one or more selected from the group consisting of maleimide compounds, cyanate ester compounds, phenol compounds, and epoxy compounds; and even more preferably contains one or more selected from the group consisting of maleimide compounds, cyanate ester compounds, and epoxy compounds. When the thermosetting resin (C) contains the above resins or compounds, it tends to yield resin compositions that have a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength, which are suitable for use in the manufacture of insulating layers for printed circuit boards.

[0129] The content of the thermosetting resin (C) in the resin composition is preferably 5 to 90 parts by mass, more preferably 10 to 80 parts by mass, even more preferably 15 to 75 parts by mass, and even more preferably 20 to 70 parts by mass, based on 100 parts by mass of the total of the dielectric powder (A) and the inorganic filler (B). When the content of the thermosetting resin (C) is within the above range, the dielectric powder (A) and the inorganic filler (B) are better dispersed, and a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards tends to be obtained, which has a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength.

[0130] (Maleimide compounds) The resin composition of this embodiment preferably contains a maleimide compound. When the thermosetting resin (C) contains a maleimide compound, it tends to yield resin compositions that have a higher dielectric constant and a lower dielectric loss tangent, superior thermal properties such as moisture absorption and heat resistance, superior laser processability, and higher metal foil peel strength, making them suitable for use in the manufacture of insulating layers for printed circuit boards.

[0131] The maleimide compound is not particularly limited, and any known compound having one or more maleimide groups in one molecule can be used as appropriate. The number of maleimide groups in one molecule of the maleimide compound is one or more, preferably two or more. The maleimide compound may be used alone or in combination of two or more.

[0132] Preferred maleimide compounds are those having an aromatic skeleton. Examples of such maleimide compounds include N-phenylmaleimide, N-hydroxyphenylmaleimide, bis(4-maleimidophenyl)methane, 2,2-bis(4-(4-maleimidophenoxy)-phenyl)propane, bis(3,5-dimethyl-4-maleimidophenyl)methane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, bis(3,5-diethyl-4-maleimidophenyl)methane, maleimide compounds represented by the following formula (1), maleimide compounds represented by the following formula (2), maleimide compounds represented by the following formula (3), and maleimide compounds represented by the following formula (4), prepolymers of these maleimide compounds, and prepolymers of the above maleimide compounds and amine compounds.

[0133] The maleimide compound more preferably includes one or more selected from the group consisting of bis(4-maleimidophenyl)methane, 2,2-bis(4-(4-maleimidophenoxy)-phenyl)propane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, a maleimide compound represented by the following formula (1), a maleimide compound represented by the following formula (2), a maleimide compound represented by the following formula (3), and a maleimide compound represented by the following formula (4). It is even more preferable to include one or more selected from the group consisting of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, a maleimide compound represented by the following formula (2), a maleimide compound represented by the following formula (3), and a maleimide compound represented by the following formula (4). When the thermosetting resin (C) contains the above-mentioned maleimide compound, it tends to yield a resin composition that has an even higher dielectric constant and an even lower dielectric loss tangent, as well as even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength, making it suitable for use in the manufacture of insulating layers for printed circuit boards.

[0134] As the maleimide compound, it is more preferable to further contain a maleimide compound represented by the following formula (2). When the thermosetting resin (C) contains the maleimide compound represented by the formula (2), it has a particularly lower dielectric tangent along with a higher dielectric constant, and further has excellent thermal properties such as moisture absorption heat resistance, and further excellent laser processing properties and higher metal foil peel strength. Tendency to obtain a resin composition suitable for manufacturing an insulating layer of a printed wiring board.

[0135]

Chemical formula

[0136] In formula (1), R 1 each independently represents a hydrogen atom or a methyl group, and n1 is an integer of 1 to 10.

[0137]

Chemical formula

[0138] In formula (2), R 2 each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, n2 is an average value, and represents 1 < n2 ≤ 5.

[0139] Examples of the alkyl group having 1 to 5 carbon atoms include linear alkyl groups such as methyl group, ethyl group, propyl group, butyl group, and pentyl group; branched alkyl groups such as isopropyl group, isobutyl group, sec-butyl group, and tert-butyl group.

[0140]

Chemical formula

[0141] In formula (3), Ra independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. q is an integer from 0 to 4. If q is an integer from 2 to 4, Ra may be the same or different within the same ring. Rb independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. r is an integer from 0 to 3. If r is 2 or 3, Rb may be the same or different within the same ring. n3 is the average value, ranging from 0.95 to 10.0.

[0142] Examples of alkyl groups having 1 to 10 carbon atoms include, in addition to the alkyl groups having 1 to 5 carbon atoms exemplified above, n-pentyl group, isopentyl group, neopentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, isononyl group, and n-decyl group.

[0143] Examples of alkyloxy groups having 1 to 10 carbon atoms include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, and n-hexyloxy groups.

[0144] Examples of alkylthio groups having 1 to 10 carbon atoms include methylthio groups and ethylthio groups.

[0145] Examples of aryl groups having 6 to 10 carbon atoms include phenyl, cyclohexylphenyl, phenol, cyanophenyl, nitrophenyl, naphthalene, biphenyl, anthracene, naphthacene, anthrasyl, pyrenyl, perylene, pentacene, benzopyrene, chrysene, pyrene, and triphenylene.

[0146] Examples of aryloxy groups having 6 to 10 carbon atoms include the phenoxy group and the p-tolyloxy group.

[0147] Examples of arylthio groups having 6 to 10 carbon atoms include phenylthio groups and p-tolylthio groups.

[0148] Examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl groups.

[0149] Examples of halogen atoms include fluorine, chlorine, bromine, and iodine.

[0150] In formula (3), Ra is preferably independently an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms.

[0151] In formula (3), q is preferably 2 or 3, and more preferably 2. Note that any group other than Ra directly attached to the benzene ring is a hydrogen atom.

[0152] In formula (3), r is preferably 0. It is also preferable that r is an integer from 1 to 3, and Rb is independently an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Any group other than Rb directly attached to the benzene ring is a hydrogen atom.

[0153] The maleimide compound represented by formula (3) may be produced by known methods. Specific production methods include, for example, the method described in WO2020 / 217679.

[0154] [ka]

[0155] In formula (4), R1 independently represents an alkyl group having 1 to 10 carbon atoms. s represents an integer from 1 to 3. R2 independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. t represents an integer from 0 to 4. R3 independently represents a group represented by the following formula (5). u represents an integer from 0 to 2. R4 represents a hydrogen atom or a group represented by the following formula (5). R5 represents a hydrogen atom or a group represented by the following formula (6). n4 represents an integer from 1 to 100.

[0156] [ka]

[0157] In formula (5), R6 independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. v represents an integer from 0 to 4. *1 indicates a bonding site with a carbon atom.

[0158] [ka]

[0159] In formula (6), each R7 independently represents an alkyl group having 1 to 10 carbon atoms. w represents an integer from 1 to 3. Each R8 independently represents a group represented by formula (5). x represents an integer from 0 to 2. *2 indicates a bonding site with a carbon atom.

[0160] In formula (4), examples of C1-C10 alkyl groups include the C1-C10 alkyl groups exemplified above. R1 is preferably a C1-C6 alkyl group. When s is an integer of 2 or more, R1 may be the same or different from each other. R1 is preferably bonded to at least one of the 2nd, 3rd, 4th, 5th, or 6th positions of the benzene ring to which R1 is bonded. R1 is preferably a methyl group, an ethyl group, or an n-propyl group. Note that groups other than R1 and R3 directly bonded to the benzene ring are hydrogen atoms. That is, for example, in formula (4), when s is 1 and u is 1, it indicates that groups other than R1 and R3 directly bonded to the benzene ring are hydrogen atoms.

[0161] In formula (4), s is preferably 1 or 2.

[0162] In formula (4), R2 can be an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and a halogen atom, for example, the respective groups and halogen atoms exemplified above. In formula (4), R2 is preferably independently a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C6-C10 aryl group, a C3-C10 cycloalkyl group, a halogen atom, or a hydroxyl group, more preferably a C1-C10 alkyl group, and even more preferably a C1-C6 alkyl group. When t is an integer of 2 or more, R2 may be the same or different from each other. R2 is preferably a methyl group, an ethyl group, or an n-propyl group. Groups other than R2 directly attached to the benzene ring are hydrogen atoms.

[0163] In formula (4), t is preferably 0, 1, or 2.

[0164] In equation (4), R3 independently represents the group shown in equation (5).

[0165] In formula (5), R6 can be an alkyl group having 1 to 10 carbon atoms, an alkyloxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and a halogen atom, for example, the respective groups and halogen atoms exemplified above.

[0166] In formula (5), R6 is preferably independently a C1-C10 alkyl group, a C1-C10 alkyloxy group, a C6-C10 aryl group, a C3-C10 cycloalkyl group, a halogen atom, or a hydroxyl group; more preferably a C1-C10 alkyl group or a C6-C10 aryl group; and even more preferably a C1-C6 alkyl group or a C6-C10 aryl group. When v is an integer of 2 or more, R6 may be the same or different from each other. Groups other than R6 directly attached to the benzene ring are hydrogen atoms.

[0167] In equation (5), v is preferably an integer between 0 and 3.

[0168] In formula (5), *1 indicates a bonding site with a carbon atom constituting the benzene ring.

[0169] In formula (4), u is preferably 0 or 1.

[0170] In formula (4), R4 represents a hydrogen atom or a group represented by formula (5). Formula (5) is as described above.

[0171] In formula (4), R5 represents a hydrogen atom or a group represented by formula (6).

[0172] In formula (6), the alkyl group having 1 to 10 carbon atoms in R7 is the same as the alkyl group having 1 to 10 carbon atoms in R1, including in preferred embodiments. w in formula (6) is the same as s in formula (4), including in preferred embodiments.

[0173] In formula (6), R8 each independently represents a group represented by formula (5). The group represented by formula (5) is as described above. In formula (6), x is the same as u in formula (4), including its preferred embodiment.

[0174] In formula (6), *2 indicates the bonding site with the carbon atom in the -CH(CH3)- group.

[0175] In equation (4), n4 is preferably an integer between 1 and 90, and more preferably an integer between 1 and 80.

[0176] The weight-average molecular weight (Mw) of the maleimide compound represented by formula (4) is preferably 400 to 500,000, and more preferably 450 to 400,000. The number-average molecular weight (Mn) of the maleimide compound represented by formula (4) is preferably 350 to 2,000, and more preferably 400 to 1,500. The molecular weight distribution (Mw / Mn) of the maleimide compound represented by formula (4) is preferably 1.001 to 500, and more preferably 1.001 to 400. In this specification, Mw, Mn, and Mw / Mn can be determined by gel permeation chromatography (GPC) on a polystyrene standard basis.

[0177] The maleimide compound represented by formula (4) may be produced by known methods. For example, a specific production method is described in Japanese Patent Application Publication No. 2023-7239.

[0178] The maleimide compound may be a commercially available product or a product manufactured by a known method. Examples of commercially available maleimide compounds include BMI-70 (bis(3-ethyl-5-methyl-4-maleimidophenyl)methane), BMI-80 (2,2-bis(4-(4-maleimidophenoxy)-phenyl)propane), and BMI-1000P (all trade names, K.I. Chemicals Co., Ltd.); BMI-3000, BMI-4000, BMI-5100, BMI-7000, and BMI-2300 (maleimide compounds represented by the above formula (1)) (all trade names, Yamato Chemical Industries, Ltd.); MIR-3000-70MT (trade name, the above formula (2) Examples include a maleimide compound represented by formula (3) above (Nippon Kayaku Co., Ltd.); NE-X-9470S (trade name, a maleimide compound represented by formula (3) above, in formula (3), Ra has two methyl groups (q=2) at each ortho position with respect to the N-maleimide group, Rb is all hydrogen atoms (r=0), and n3 is an integer between 1 and 10, DIC Corporation), and NE-X-9480S (trade name, a maleimide compound represented by formula (3) above, DIC Corporation); and NE-X-9500 (trade name, a maleimide compound represented by formula (4) above, DIC Corporation).

[0179] The maleimide compound content is preferably 15 to 85 parts by mass, more preferably 20 to 80 parts by mass, and even more preferably 25 to 75 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. When the maleimide compound content is within the above range, it tends to yield a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards, which has an even higher dielectric constant and a lower dielectric loss tangent, even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength. When the resin composition contains two or more maleimide compounds, it is preferable that their total amount is within the above range.

[0180] (Cyanate ester compounds) The resin composition of this embodiment preferably contains a cyanate ester compound. When the thermosetting resin (C) contains a cyanate ester compound, it tends to yield resin compositions that have a higher dielectric constant and a lower dielectric loss tangent, superior thermal properties such as moisture absorption and heat resistance, superior laser processability, and higher metal foil peel strength, making them suitable for use in the manufacture of insulating layers for printed circuit boards.

[0181] Any known cyanate ester compound can be used as long as it has two or more cyanate groups (hereinafter also referred to as "cyanate ester group" or "cyanate group") directly bonded to aromatic rings in one molecule. The cyanate ester compound may be used alone or in combination of two or more.

[0182] Examples of cyanate ester compounds include phenol novolac type cyanate ester compounds, cresol novolac type cyanate ester compounds, naphthalene ring-containing novolac type cyanate ester compounds, allyl group-containing novolac type cyanate ester compounds, naphthol aralkyl type cyanate ester compounds, naphthylene ether type cyanate ester compounds, xylene resin type cyanate ester compounds, bisphenol M type cyanate ester compounds, bisphenol A type cyanate ester compounds, diallylbisphenol A type cyanate ester compounds, bisphenol E type cyanate ester compounds, and bisphenol F type cyanate ester compounds. Examples include biphenylaralkyl type cyanate ester compounds, bis(3,3-dimethyl-4-cyanatophenyl)methane, 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, 1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis(4-cyanatophenyl) ether, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)sulfone. Furthermore, these cyanate ester compounds may be prepolymers or polymers of cyanate ester compounds.

[0183] The cyanate ester compound preferably includes one or more selected from the group consisting of phenol novolac type cyanate ester compounds, naphthol aralkyl type cyanate ester compounds, naphthylene ether type cyanate ester compounds, xylene resin type cyanate ester compounds, bisphenol M type cyanate ester compounds, bisphenol A type cyanate ester compounds, diallylbisphenol A type cyanate ester compounds, bisphenol E type cyanate ester compounds, bisphenol F type cyanate ester compounds, and biphenyl aralkyl type cyanate ester compounds, as well as prepolymers or polymers of these cyanate ester compounds. It is more preferably included one or more selected from the group consisting of naphthol aralkyl type cyanate ester compounds and bisphenol A type cyanate ester compounds, and even more preferably included a naphthol aralkyl type cyanate ester compound. When the thermosetting resin (C) contains the above-mentioned cyanate ester compound, a resin composition is obtained that has an even higher dielectric constant and an even lower dielectric loss tangent, as well as even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength, which is suitable for use in the manufacture of insulating layers for printed circuit boards.

[0184] As the naphthol aralkyl type cyanate ester compound, the compound represented by the following formula (7) is more preferred. When the thermosetting resin (C) contains the compound represented by formula (7), it tends to yield a resin composition suitable for use in the manufacture of insulating layers for printed circuit boards, which has an even higher dielectric constant and an even lower dielectric loss tangent, even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength.

[0185] [ka]

[0186] In formula (7), R6 independently represents either a hydrogen atom or a methyl group, with hydrogen atoms being preferred. Also in formula (7), n5 is an integer of 1 or more, preferably an integer between 1 and 20, and more preferably an integer between 1 and 10.

[0187] As the bisphenol A type cyanate ester compound, one or more compounds selected from the group consisting of 2,2-bis(4-cyanatophenyl)propane and 2,2-bis(4-cyanatophenyl)propane prepolymers may be used. Such bisphenol A type cyanate ester compounds may be commercially available products, for example, Primaset® BADCy (trade name, Lonza Co., Ltd., 2,2-bis(4-cyanatophenyl)propane, cyanate ester group equivalent: 139 g / eq.) and CA210 (trade name, Mitsubishi Gas Chemical Co., Ltd., prepolymer of 2,2-bis(4-cyanatophenyl)propane, cyanate ester group equivalent: 139 g / eq.).

[0188] These cyanate ester compounds may be produced by known methods. Specific production methods include, for example, those described in Japanese Patent Publication No. 2017-195334 (particularly paragraphs 0052-0057).

[0189] The cyanate ester compound content is preferably 1 to 65 parts by mass, more preferably 2 to 60 parts by mass, even more preferably 3 to 55 parts by mass, even more preferably 4 to 50 parts by mass, even more preferably 5 to 45 parts by mass, and even more preferably 6 to 40 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. When the cyanate ester compound content is within the above range, it tends to yield a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards, which has an even higher dielectric constant and an even lower dielectric loss tangent, even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength. When the resin composition contains two or more cyanate ester compounds, it is preferable that their total amount is within the above range.

[0190] (Epoxy compound) The resin composition of this embodiment preferably contains an epoxy compound. When the thermosetting resin (C) contains an epoxy compound, it tends to yield resin compositions that have a higher dielectric constant and a lower dielectric loss tangent, better thermal properties such as moisture absorption and heat resistance, better laser processability, and higher metal foil peel strength, making them suitable for use in the manufacture of insulating layers for printed circuit boards.

[0191] The epoxy compound is not particularly limited; any known compound having one or more epoxy groups in one molecule can be used as appropriate. The number of epoxy groups in one molecule of the epoxy compound is one or more, preferably two or more. The epoxy compound may be used alone or in combination of two or more.

[0192] Conventionally known epoxy compounds and epoxy resins can be used as epoxy compounds. For example, biphenyl aralkyl epoxy resins, naphthalene epoxy resins, bis-naphthalene epoxy resins, polyfunctional phenol epoxy resins, naphthylene ether epoxy resins, butadiene skeleton-containing epoxy resins, phenol aralkyl epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins, xylene novolac epoxy resins, naphthalene skeleton-modified novolac epoxy resins, dicyclopentadiene novolac epoxy resins, biphenyl novolac epoxy resins, phenol aralkyl novolac epoxy resins, naphthol aralkyl novolac epoxy resins, aralkyl novolac epoxy resins, aromatic hydrocarbon formaldehyde epoxy compounds, anthraquinone epoxy compounds, anthracene epoxy compounds Examples include epoxy resins, naphthol aralkyl epoxy compounds, dicyclopentadiene epoxy resins, Zyloc epoxy compounds, bisphenol A epoxy resins, bisphenol E epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bisphenol A novolac epoxy resins, phenol epoxy compounds, biphenyl epoxy resins, aralkyl novolac epoxy resins, triazine skeleton epoxy compounds, triglycidyl isocyanurates, alicyclic epoxy resins, polyol epoxy resins, glycidylamines, glycidyl ester resins, compounds in which the double bonds of double bond-containing compounds such as butadiene are epoxidized, and compounds obtained by the reaction of hydroxyl group-containing silicone resins with epichlorohydrin.

[0193] The epoxy compound preferably contains one or more selected from the group consisting of biphenylaralkyl epoxy resins, naphthalene epoxy resins, naphthylene ether epoxy resins, and butadiene skeleton-containing epoxy resins; more preferably contains one or more selected from the group consisting of naphthalene epoxy resins and biphenylaralkyl epoxy resins; and even more preferably contains a biphenylaralkyl epoxy resin. When the thermosetting resin (C) contains the above epoxy resins, it tends to yield resin compositions that have an even higher dielectric constant and an even lower dielectric loss tangent, even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength, which are suitable for use in manufacturing insulating layers of printed circuit boards.

[0194] The biphenyl aralkyl epoxy resin is preferably a compound represented by the following formula (8). When the thermosetting resin (C) contains a compound represented by formula (8), it tends to yield a resin composition suitable for use in the manufacture of insulating layers for printed circuit boards, which has an even higher dielectric constant and an even lower dielectric loss tangent, even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength.

[0195] [ka]

[0196] In formula (8), ka represents an integer of 1 or more, preferably an integer between 1 and 20, and more preferably an integer between 1 and 10.

[0197] As the biphenyl aralkyl type epoxy resin, commercially available products may be used, or products manufactured by known methods may be used. Examples of commercially available products include NC-3000, NC-3000L, NC-3000H, and NC-3000FH (compounds represented by the above formula (8), in which ka is an integer from 1 to 10) (all trade names, Nippon Kayaku Co., Ltd.).

[0198] The naphthalene-type epoxy resin is preferably a compound represented by the following formula (9).

[0199] [ka]

[0200] In formula (9), R 3b Each of these independently represents a hydrogen atom, a C1-C5 alkyl group (e.g., a methyl group or an ethyl group), an aralkyl group, a benzyl group, a naphthyl group, a naphthyl group containing at least one glycidyloxy group, or a naphthylmethyl group containing at least one glycidyloxy group, where n is an integer of 0 or more (e.g., 0-2).

[0201] A commercially available product of the compound represented by the above formula (9) is, for example, EPICLON® EXA-4032-70M (where n=0 in the above formula (9), R 3b (where all are hydrogen atoms), EPICLON(registered trademark) HP-4710 (in the above formula (9), n=0, R 3b Examples include naphthylmethyl groups containing at least one glycidyloxy group (the above are trade names, DIC Corporation).

[0202] The naphthylene ether type epoxy resin is preferably a bifunctional epoxy compound represented by the following formula (10) or a polyfunctional epoxy compound represented by the following formula (11), or a mixture thereof.

[0203] [ka]

[0204] In formula (10), R 13 Each of these independently represents a hydrogen atom, a C1-C3 alkyl group (e.g., a methyl group or an ethyl group), or a C2-C3 alkenyl group (e.g., a vinyl group, an allyl group, or a propenyl group).

[0205] [ka]

[0206] In formula (11), R 14 Each of these independently represents a hydrogen atom, a C1-C3 alkyl group (e.g., a methyl group or an ethyl group), or a C2-C3 alkenyl group (e.g., a vinyl group, an allyl group, or a propenyl group).

[0207] The naphthylene ether type epoxy resin may be a commercially available product or a product manufactured by a known method. Examples of commercially available products include HP-6000, EXA-7300, EXA-7310, EXA-7311, EXA-7311L, EXA7311-G3, EXA7311-G4, EXA-7311G4S, and EXA-7311G5 (all trade names, DIC Corporation). Among these, HP-6000 (trade name) is preferred.

[0208] The butadiene skeleton-containing epoxy resin can be any epoxy resin having a butadiene skeleton and epoxy groups in its molecule. Examples of such resins include the butadiene skeleton-containing epoxy resins represented by the following formulas (12) to (14).

[0209] [ka]

[0210] In equation (12), X represents an integer from 1 to 100, and Y represents an integer from 0 to 100.

[0211] [ka]

[0212] In formula (13), R represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, a and b each independently represent an integer from 1 to 100, and c and d each independently represent an integer from 0 to 100. Examples of alkyl groups include methyl, ethyl, propyl, and butyl groups.

[0213] [ka]

[0214] In equation (14), e represents an integer between 24 and 35, and f represents an integer between 8 and 11.

[0215] The butadiene skeleton-containing epoxy resin may be a commercially available product or a product manufactured by a known method. Examples of commercially available products include R-15EPT and R-45EPT (compounds in formula (12) above where X=50 and Y=0) (trade names, Nagase ChemteX Corporation); Epollead® PB3600 and PB4700 (trade names, Daicel Corporation); and Nippon Oil Polybutadiene E-1000-3.5 (trade name, Nippon Petrochemical Co., Ltd.).

[0216] The epoxy compound content is preferably 1 to 50 parts by mass, more preferably 10 to 45 parts by mass, and even more preferably 20 to 40 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. When the epoxy compound content is within the above range, it tends to yield a resin composition suitable for use in manufacturing the insulating layer of printed circuit boards, which has an even higher dielectric constant and an even lower dielectric loss tangent, even better thermal properties such as moisture absorption and heat resistance, even better laser processability, and even higher metal foil peel strength. When the resin composition contains two or more epoxy compounds, it is preferable that their total amount is within the above range.

[0217] (Phenol compounds) The resin composition of this embodiment may also contain a phenolic compound. As the phenolic compound, any known compound having two or more phenolic hydroxy groups in one molecule can be appropriately used, and the type thereof is not particularly limited. The phenolic compound may be used alone or in combination of two or more kinds.

[0218] Examples of the phenolic compound include cresol novolak type phenolic resin, biphenyl aralkyl type phenolic resin represented by the following formula (15), naphthol aralkyl type phenolic resin represented by the following formula (16), aminotriazine novolak type phenolic resin, naphthalene type phenolic resin, phenol novolak resin, alkylphenol novolak resin, bisphenol A type novolak resin, dicyclopentadiene type phenolic resin, zyloc type phenolic resin, terpene-modified phenolic resin, and polyvinyl phenols.

[0219] Among these, one or more selected from the group consisting of cresol novolak type phenolic resin, biphenyl aralkyl type phenolic resin represented by formula (15), naphthol aralkyl type phenolic resin represented by formula (16), aminotriazine novolak type phenolic resin, and naphthalene type phenolic resin are preferable because excellent moldability and surface hardness can be obtained, and one or more selected from the group consisting of biphenyl aralkyl type phenolic resin represented by formula (15) and naphthol aralkyl type phenolic resin represented by formula (16) are more preferable.

[0220]

Chemical formula

[0221] In formula (15), R 4 each independently represents a hydrogen atom or a methyl group, and n4 is an integer of 1 to 10.

[0222]

Chemical formula

[0223] In formula (16), R 5 Each of these independently represents either a hydrogen atom or a methyl group, and n5 is an integer from 1 to 10.

[0224] The content of the phenol compound is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 30 parts by mass, based on 100 parts by mass of the total resin solids of the resin composition. A phenol compound content within the above range tends to result in superior adhesion, flexibility, and other properties. If the resin composition contains two or more phenol compounds, it is preferable that their total amount falls within the above range.

[0225] (Modified polyphenylene ether compound) The resin composition of this embodiment may also contain a modified polyphenylene ether compound. Modified polyphenylene ether compounds are not particularly limited, and any known compounds can be used as appropriate, as long as some or all of the terminal ends of the polyphenylene ether compound are modified. In this specification, "modified" of a modified polyphenylene ether compound means that some or all of the terminal ends of the polyphenylene ether compound are substituted with a reactive functional group. Examples of reactive functional groups include groups having a carbon-carbon unsaturated double bond and hydroxyl groups. Modified polyphenylene ether compounds may be used individually or in combination of two or more.

[0226] Examples of polyphenylene ether compounds related to modified polyphenylene ether compounds include polymers containing at least one structural unit selected from the structural unit represented by formula (17), the structural unit represented by formula (18), and the structural unit represented by formula (19).

[0227] [ka]

[0228] In formula (17), R8, R9, R 10, and R 11 Each of these independently represents an alkyl group, aryl group, halogen atom, or hydrogen atom having 6 or fewer carbon atoms.

[0229] [ka]

[0230] In formula (18), R 12 , R 13 , R 14 , R 18 , and R 19 Each independently represents an alkyl group or phenyl group having 6 or fewer carbon atoms. 15 , R 16 , and R 17 Each of these independently represents a hydrogen atom, an alkyl group having 6 or fewer carbon atoms, or a phenyl group.

[0231] [ka]

[0232] In formula (19), R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , and R 27 Each of these independently represents a hydrogen atom, an alkyl group having 6 or fewer carbon atoms, or a phenyl group. -A- represents a linear, branched, or cyclic divalent hydrocarbon group having 20 or fewer carbon atoms.

[0233] Examples of -A- in formula (19) include, but are not limited to, divalent organic groups such as methylene group, ethylidene group, 1-methylethylidene group, 1,1-propyridene group, 1,4-phenylenebis(1-methylethylidene) group, 1,3-phenylenebis(1-methylethylidene) group, cyclohexylidene group, phenylmethylene group, naphthylmethylene group, and 1-phenylethylidene group.

[0234] Examples of the modified polyphenylene ether compound include modified polyphenylene ether compounds in which part or all of the ends of the polyphenylene ether compound are modified with functional groups such as ethylenically unsaturated groups such as vinylbenzyl groups, epoxy groups, amino groups, hydroxyl groups, mercapto groups, carboxyl groups, methacryloyl groups, and silyl groups.

[0235] Examples of the modified polyphenylene ether compound having a hydroxyl group at the end include SA90 (trade name, SABIC Innovative Plastics) and the like. Examples of the modified polyphenylene ether compound having a methacryloyl group at the end include SA9000 (trade name, SABIC Innovative Plastics) and the like.

[0236] The method for producing the modified polyphenylene ether compound is not particularly limited as long as the effects of the present invention can be obtained. For example, it can be produced by the method described in Japanese Patent No. 4591665.

[0237] The modified polyphenylene ether compound more preferably includes a modified polyphenylene ether compound having an ethylenically unsaturated group at the end. Examples of the ethylenically unsaturated group include alkenyl groups such as ethenyl group, allyl group, acryloyl group, methacryloyl group, propenyl group, butenyl group, hexenyl group, and octenyl group; cycloalkenyl groups such as cyclopentenyl group and cyclohexenyl group; and alkenylaryl groups such as vinylbenzyl group and vinylnaphthyl group. Among them, the vinylbenzyl group is preferred. The ethylenically unsaturated groups at the end may be single or plural, and may be the same functional group or different functional groups.

[0238] As the modified polyphenylene ether compound having an ethylenically unsaturated group at the end, the compound represented by the following formula (20) is preferred.

[0239] [Chemical formula]

[0240] In formula (20), X represents an aromatic group, and -(YO) m - indicates a polyphenylene ether moiety. R1, R2, and R3 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, or an alkynyl group, m is an integer from 1 to 100, n is an integer from 1 to 6, and q is an integer from 1 to 4. m is preferably an integer from 1 to 50, more preferably an integer from 1 to 30. Also, n is preferably an integer from 1 to 4, more preferably 1 or 2, and ideally 1. Also, q is preferably an integer from 1 to 3, more preferably 1 or 2, and ideally 2.

[0241] The aromatic group represented by X in formula (20) can be a group obtained by removing q hydrogen atoms from one of the ring structures selected from a benzene ring structure, a biphenyl ring structure, an indenyl ring structure, and a naphthalene ring structure (for example, a phenylene group, a biphenylene group, an indenylene group, and a naphthylene group). Among these, the biphenylene group is preferred. Here, the aromatic group represented by X may include a diphenyl ether group in which an aryl group is bonded by an oxygen atom, a benzophenone group bonded by a carbonyl group, a 2,2-diphenylpropane group bonded by an alkylene group, and so on. Furthermore, the aromatic group may be substituted with common substituents such as alkyl groups (preferably alkyl groups having 1 to 6 carbon atoms, especially methyl groups), alkenyl groups, alkynyl groups, or halogen atoms. However, since the aromatic group is substituted on the polyphenylene ether moiety via an oxygen atom, the limit on the number of common substituents depends on the number of polyphenylene ether moieties.

[0242] As the YO of the polyphenylene ether portion in formula (20), the structural units represented by formula (17), formula (18), and formula (19) can be used. Among these, it is more preferable to include the structural unit represented by formula (17).

[0243] Furthermore, in the modified polyphenylene ether compound represented by formula (20), the number average molecular weight is preferably 500 to 7000. Also, in formula (20), a compound with a minimum melt viscosity of 50000 Pa·s or less can be used. In formula (20), the number average molecular weight is preferably 1000 to 7000, and the minimum melt viscosity is more preferably 50000 Pa·s or less. The number-average molecular weight is measured using gel permeation chromatography according to standard procedures. The number-average molecular weight is preferably between 1000 and 3000. The minimum melt viscosity is measured using a dynamic viscoelasticity measuring device according to a standard method. The minimum melt viscosity is more preferably 500 Pa·s or more and 50,000 Pa·s or less.

[0244] Among the modified polyphenylene ether compounds, those represented by formula (21) below are preferred.

[0245] [ka]

[0246] In formula (21), X is an aromatic group, and -(YO) m -and-(OY) m Each of the hyphens represents a polyphenylene ether moiety, and m represents an integer from 1 to 100. m is preferably an integer from 1 to 50, and more preferably an integer from 1 to 30. In equation (21), X, -(YO) m - and m are equivalent to those in equation (20). -(OY) in equation (21) m - is -(YO) in equation (20) m - This is synonymous with -

[0247] In equations (20) and (21), X is equation (22), equation (23), or equation (24), and in equations (20) and (21), -(YO) m -and-(OY) m- Preferably, the structure is one in which formula (25) or formula (26) is arranged in sequence, or in which formula (25) and formula (26) are arranged in a block or randomly.

[0248] [ka]

[0249] [ka]

[0250] In formula (23), R 28 , R 29 , R 30 , and R 31 Each of these independently represents either a hydrogen atom or a methyl group. -B- is a linear, branched, or cyclic divalent hydrocarbon group with 20 or fewer carbon atoms. For -B-, the same specific example as -A- in equation (19) can be given.

[0251] [ka]

[0252] In formula (24), -B- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or fewer carbon atoms. For -B-, the same specific example as -A- in equation (19) can be given.

[0253] [ka]

[0254] [ka]

[0255] The method for producing a modified polyphenylene ether compound having the structure represented by formula (21) is not particularly limited, and for example, it can be produced by vinyl benzyl etherification of the terminal phenolic hydroxyl group of a difunctional phenylene ether oligomer obtained by oxidative coupling of a difunctional phenol compound and a monofunctional phenol compound. Furthermore, commercially available modified polyphenylene ether compounds can be used, and for example, OPE-2St1200 and OPE-2st2200 (both trade names, Mitsubishi Gas Chemical Company, Inc.) can be suitably used.

[0256] The content of the modified polyphenylene ether compound is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 30 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. When the content of the modified polyphenylene ether compound is within the above range, the low dielectric loss tangent and reactivity tend to be further improved. If the resin composition contains two or more modified polyphenylene ether compounds, it is preferable that their total amount falls within the above range.

[0257] (Alkenyl-substituted nadiimide compounds) The resin composition of this embodiment may also contain an alkenyl-substituted nadiimide compound. The alkenyl-substituted nadiimide compound is not particularly limited as long as it is a compound having one or more alkenyl-substituted nadiimide groups in one molecule. The alkenyl-substituted nadiimide compound may be used alone or in combination of two or more.

[0258] Examples of alkenyl-substituted nadiimide compounds include the compound represented by the following formula (27).

[0259] [ka]

[0260] In formula (27), R1 independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (e.g., a methyl group or an ethyl group), and R2 represents an alkylene group, phenylene group, biphenylene group, naphthylene group, or a group represented by formula (28) or formula (29) having 1 to 6 carbon atoms.

[0261] [ka]

[0262] In formula (28), R3 represents a methylene group, an isopropylidene group, CO, O, S, or SO2.

[0263] [ka]

[0264] In formula (29), R4 independently represents either an alkylene group having 1 to 4 carbon atoms or a cycloalkylene group having 5 to 8 carbon atoms.

[0265] The alkenyl-substituted nadiimide compound represented by formula (27) may be a commercially available product or a manufactured product prepared according to known methods. Examples of commercially available products include BANI-M and BANI-X (both trade names, Maruzen Petrochemical Co., Ltd.).

[0266] The content of the alkenyl-substituted nadiimide compound is preferably 1 part by mass or more and 50 parts by mass or less, based on 100 parts by mass of the total resin solids of the resin composition.

[0267] (Oxetane resin) The resin composition of this embodiment may also contain an oxetane resin. The oxetane resin is not particularly limited, and generally known resins can be used. The oxetane resin may be used alone or in combination of two or more types.

[0268] Examples of oxetane resins include oxetane, alkyl oxetanes such as 2-methyloxetane, 2,2-dimethyloxetane, 3-methyloxetane, and 3,3-dimethyloxetane, 3-methyl-3-methoxymethyloxetane, 3,3-di(trifluoromethyl)perfluorooxetane, 2-chloromethyloxetane, 3,3-bis(chloromethyl)oxetane, biphenyl-type oxetane, OXT-101 (trade name, Toagosei Co., Ltd.), and OXT-121 (trade name, Toagosei Co., Ltd.).

[0269] The oxetane resin content is preferably 1 part by mass or more and 50 parts by mass or less, based on 100 parts by mass of the total resin solids of the resin composition.

[0270] (Benzoxazine compound) The resin composition of this embodiment may also contain a benzoxazine compound. The benzoxazine compound is not particularly limited as long as it has two or more dihydrobenzoxazine rings in one molecule; generally known compounds can be used. The benzoxazine compound may be used alone or in combination of two or more.

[0271] Examples of benzoxazine compounds include bisphenol A type benzoxazine (BA-BXZ), bisphenol F type benzoxazine (BF-BXZ), and bisphenol S type benzoxazine (BS-BXZ) (all trade names, Konishi Chemical Industry Co., Ltd.).

[0272] The content of the benzoxazine compound is preferably 1 part by mass or more and 50 parts by mass or less, based on 100 parts by mass of the total resin solids of the resin composition.

[0273] (Compounds having polymerizable unsaturated groups) The resin composition of this embodiment may contain a compound having polymerizable unsaturated groups. The polymerizable unsaturated group compound is not particularly limited, and generally known compounds can be used. The polymerizable unsaturated group compound may be used alone or in combination of two or more compounds.

[0274] Examples of polymerizable unsaturated compounds include vinyl compounds such as ethylene, propylene, styrene, divinylbenzene, and divinylbiphenyl; monohydric or polyhydric alcohol (meth)acrylates such as methyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; epoxy (meth)acrylates such as bisphenol A type epoxy (meth)acrylate and bisphenol F type epoxy (meth)acrylate; and benzocyclobutene resins.

[0275] The content of the polymerizable unsaturated compound is preferably 1 part by mass or more and 50 parts by mass or less, based on 100 parts by mass of the total resin solids of the resin composition.

[0276] [Thermoplastic elastomer] The resin composition of this embodiment may also contain a thermoplastic elastomer. The thermoplastic elastomer is not particularly limited as long as it is a thermoplastic elastomer. The thermoplastic elastomer may be used alone or in combination of two or more types.

[0277] Examples of thermoplastic elastomers include styrene-based elastomers and other thermoplastic elastomers other than styrene-based elastomers.

[0278] Examples of styrene-based elastomers include styrene-butadiene random copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, styrene-hydrogenated butadiene-styrene block copolymer, styrene-hydrogenated isoprene-styrene block copolymer, styrene-butadiene block copolymer, styrene-isoprene block copolymer, styrene-hydrogenated butadiene block copolymer, styrene-hydrogenated isoprene block copolymer, and styrene-hydrogenated (isoprene / butadiene) block copolymer.

[0279] In the polystyrene block structure, styrene (styrene unit) may have substituents. Examples of such styrenes include α-methylstyrene, 3-methylstyrene, 4-propylstyrene, and 4-cyclohexylstyrene.

[0280] The styrene content in the styrene-based elastomer is preferably 10% by mass or more, and more preferably 20% by mass or more, per 100% by mass of the styrene-based elastomer. The upper limit of the styrene content is, for example, less than 100% by mass, preferably less than 99% by mass, and more preferably 70% by mass or less. In this specification, the styrene content is a value expressed as (a) / (b) × 100 (unit: mass%), where (a)g is the mass of styrene units contained in the styrene-based elastomer and (b)g is the total mass of the styrene-based elastomer.

[0281] Commercially available styrene-based elastomers may be used. Examples of commercially available products include TR2630 and TR2003 (trade names, JSR Corporation) as styrene-butadiene-styrene block copolymers; SIS5250 (trade name, JSR Corporation) as a styrene-isoprene-styrene block copolymer; SEPTON® 2104 (Kuraray Co., Ltd.) as a styrene-hydrogenated isoprene-styrene block copolymer; and H-1043 (trade name, Asahi Kasei Corporation) as a styrene-hydrogenated butadiene-styrene block copolymer.

[0282] Examples of thermoplastic elastomers other than styrene-based elastomers include polyisoprene, polybutadiene, butyl rubber, ethylene propylene rubber, fluororubber, silicone rubber, and their hydrogenated compounds, as well as their alkyl compounds.

[0283] The content of thermoplastic elastomer is preferably 0.5 parts by mass or more and 30 parts by mass or less, more preferably 1 part by mass or more and 25 parts by mass or less, even more preferably 1 part by mass or more and 20 parts by mass or less, even more preferably 2 parts by mass or more and 15 parts by mass or less, and even more preferably 3 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total resin solids of the resin composition. If the resin composition contains two or more types of thermoplastic elastomers, it is preferable that their total amount be within the above range.

[0284] [Other fillers] The resin composition of this embodiment may further contain fillers other than the dielectric powder (A) and the inorganic filler (B) (hereinafter also simply referred to as "other fillers"). When the resin composition contains other fillers, the dispersibility between the dielectric powder (A) and inorganic filler (B) and the thermosetting resin (C) tends to be better. Furthermore, when the resin composition contains other fillers, there is a tendency to obtain a cured product with even better thermal properties such as moisture absorption and heat resistance, a high glass transition temperature, a low coefficient of thermal expansion, low water absorption, and better dielectric properties (high dielectric constant and low dielectric loss tangent). Moreover, when the resin composition contains other fillers, there is a tendency to obtain an insulating layer with better metal foil peel strength and more suitable surface hardness. The other fillers are not particularly limited as long as they are different from the dielectric powder (A) and inorganic filler (B). The other fillers may be used individually or in combination of two or more types.

[0285] The relative permittivity (Dk) of the other fillers, measured according to the cavity resonator perturbation method at a frequency of 10 GHz, is preferably less than 12.0, more preferably 10.0 or less, even more preferably 8.0 or less, and even more preferably 7.0 or less. The lower limit of the relative permittivity is not particularly limited, but for example, it is 0.1 or more.

[0286] The dielectric loss tangent (Df) of the other fillers, measured according to the cavity resonator perturbation method at a frequency of 10 GHz, is preferably 0.015 or less, more preferably 0.010 or less, and even more preferably 0.008 or less. When the dielectric loss tangent is 0.015 or less, an insulating layer with an even lower dielectric loss tangent tends to be obtained. The lower limit of the dielectric loss tangent is not particularly limited, but for example, it is 0.001 or more.

[0287] The relative permittivity and dielectric loss tangent of the other fillers can be measured and calculated using the same method as for the relative permittivity of the dielectric powder (A) described above. The specific measurement methods for the relative permittivity and dielectric loss tangent are as described in the examples.

[0288] For the other fillers, the absorbance at a wavelength of 9.3 μm in the infrared absorption spectrum obtained using the KBr tablet method of Fourier transform infrared spectroscopy is preferably less than 0.70, and more preferably 0.60 or less. The lower limit of the absorbance is not particularly limited, but is 0.00 or higher. The absorbance of the other fillers can be measured and calculated in the same manner as for the inorganic filler (B) described above.

[0289] The melting point of the other fillers is preferably above 1600°C, and more preferably above 1610°C. The upper limit of the melting point of the other fillers is, for example, 2500°C or less. The melting point of the other fillers can be measured, for example, by differential thermogravimetric analysis. The specific method for measuring the melting point is as described in the examples.

[0290] The average particle size (D50) of the other fillers is preferably 0.10 μm or more and 10.00 μm or less, and more preferably 0.30 μm or more and 5.00 μm or less. The average particle size (D50) of the other fillers can be measured and calculated in the same manner as the average particle size (D50) of the dielectric powder (A) described above.

[0291] Other fillers include, for example, silica, silicon compounds (e.g., white carbon), metal oxides (e.g., alumina, molybdenum compounds (e.g., molybdic acid, zinc molybdate such as ZnMoO4 and Zn3Mo2O9, ammonium molybdate, sodium molybdate, potassium molybdate, calcium molybdate, molybdenum disulfide, molybdenum trioxide, molybdic acid hydrate, zinc ammonium molybdate hydrate such as (NH4)Zn2Mo2O9·(H3O)), zinc oxide, magnesium oxide, and zirconium oxide), metal nitrides (e.g., boron nitride, silicon nitride, and aluminum nitride), metal sulfides (e.g., barium sulfate), metal hydroxides (e.g., aluminum hydroxide, heat-treated aluminum hydroxide (e.g., aluminum hydroxide that has been heat-treated to reduce some of its crystal water), boehmite, and magnesium hydroxide), zinc oxide Examples of fillers include inorganic fillers such as metal nanoparticles that have been insulated from metals such as gold, silver, palladium, copper, nickel, iron, cobalt, zinc, Mn-Mg-Zn, Ni-Zn, Mn-Zn, carbonyl iron, Fe-Si, Fe-Al-Si, and Fe-Ni; organic fillers such as rubber powders of styrene type, butadiene type, and acrylic type; core-shell type; silicone resin powder; silicone rubber powder; and silicone composite powder.

[0292] Among these, the other fillers preferably include one or more selected from the group consisting of silica, alumina, talc other than calcined talc such as fine talc powder or powdered talc, aluminum nitride, boron nitride, boehmite, aluminum hydroxide, zinc molybdate, silicone rubber powder, and silicone composite powder, and more preferably include one or more selected from the group consisting of silica, talc other than calcined talc such as fine talc powder or powdered talc, and zinc molybdate. As silica, it is preferable to include molten spherical silica. As alumina, it is preferable to include spherical alumina.

[0293] Other fillers may be surface-treated fillers in which an inorganic oxide is formed on at least a portion of the surface of the filler core particles. Examples of such fillers include surface-treated molybdenum compound particles (supported type) in which an inorganic oxide is formed on at least a portion of the surface of core particles made of a molybdenum compound.

[0294] The inorganic oxide only needs to be applied to at least a portion of the surface of the filler core particles. The inorganic oxide may be applied partially to the surface of the filler core particles, or it may be applied so as to cover the entire surface of the filler core particles. It is preferable that the inorganic oxide is applied uniformly so as to cover the entire surface of the filler core particles, that is, a uniform film of inorganic oxide is formed on the surface of the filler core particles.

[0295] Examples of surface-treated molybdenum compound particles (supported type) include those obtained by surface-treating molybdenum compound particles with a silane coupling agent, or those obtained by treating their surface with an inorganic oxide using methods such as the sol-gel method or liquid-phase deposition method.

[0296] As inorganic oxides, those with excellent heat resistance are preferred, and while the type is not particularly limited, metal oxides are more preferred. Examples of metal oxides include SiO2, Al2O3, TiO2, ZnO, In2O3, SnO2, NiO, CoO, V2O5, CuO, MgO, and ZrO2. These can be used individually or in appropriate combinations of two or more. Among these, one or more selected from the group consisting of silica (SiO2), titania (TiO2), alumina (Al2O3), and zirconia (ZrO2) are preferred in terms of heat resistance, insulation properties, and cost.

[0297] As surface-treated molybdenum compound particles, it is preferable that an inorganic oxide is applied to at least a part or all of the surface of the core particles made of the molybdenum compound, i.e., at least a part or all of the outer circumference of the core particles. Among such surface-treated molybdenum compound particles, it is more preferable that silica is applied as an inorganic oxide to at least a part or all of the surface of the core particles made of the molybdenum compound, i.e., at least a part or all of the outer circumference of the core particles. It is more preferable that the core particles made of the molybdenum compound are one or more selected from the group consisting of molybdic acid, zinc molybdate, and zinc ammonium molybdate hydrate.

[0298] The thickness of the inorganic oxide coating on the surface can be set appropriately according to the desired performance and is not particularly limited. Preferably, the thickness is 3 nm to 500 nm, as this allows for the formation of a uniform inorganic oxide film and provides superior adhesion to the filler core particles.

[0299] From the viewpoint of dispersibility in the resin composition, the average particle size (D50) of the surface-treated molybdenum compound particles is between 0.10 μm and 10.00 μm. The average particle size (D50) of the surface-treated molybdenum compound particles can be measured and calculated in the same way as the average particle size (D50) of the dielectric powder (A) described above.

[0300] Core particles made of molybdenum compounds can be manufactured by various known methods such as pulverization and granulation, and the manufacturing method is not particularly limited. Commercially available products may also be used.

[0301] The method for producing surface-treated molybdenum compound particles is not particularly limited. For example, various known methods such as the sol-gel method, liquid-phase deposition method, immersion coating method, spray coating method, printing method, electroless plating method, sputtering method, vapor deposition method, ion plating method, and CVD method can be appropriately employed to apply an inorganic oxide or its precursor to the surface of core particles made of a molybdenum compound, thereby obtaining surface-treated molybdenum compound particles. The method for applying the inorganic oxide or its precursor to the surface of core particles made of a molybdenum compound can be either a wet method or a dry method.

[0302] A preferred method for producing surface-treated molybdenum compound particles involves, for example, dispersing a molybdenum compound (core particles) in an alcohol solution containing a metal alkoxide such as silicon alkoxide (alkoxysilane) or aluminum alkoxide, adding a mixed solution of water, alcohol, and a catalyst dropwise while stirring, hydrolyzing the alkoxide to form a low-refractive-index coating of silicon oxide or aluminum oxide on the compound surface, then separating the resulting powder into solid and liquid components, vacuum drying, and heat treatment. Another preferred method involves, for example, dispersing a molybdenum compound (core particles) in an alcohol solution containing a metal alkoxide such as silicon alkoxide or aluminum alkoxide, mixing under high temperature and low pressure to form a coating of silicon oxide or aluminum oxide on the compound surface, then vacuum drying and pulverizing the resulting powder. These methods yield surface-treated molybdenum compound particles having a metal oxide coating of silica or alumina on the surface of the molybdenum compound.

[0303] The content of other fillers is preferably 50 parts by mass or more and 300 parts by mass or less, based on 100 parts by mass of the total resin solids in the resin composition. If the resin composition of this embodiment contains two or more types of other fillers, it is preferable that the total amount is within the above range.

[0304] [Silane coupling agent] The resin composition of this embodiment may also contain a silane coupling agent. When a resin composition contains a silane coupling agent, the dispersibility of the dielectric powder (A), the inorganic filler (B), and other fillers added as needed is improved, and the adhesive strength between each component of the resin composition and the substrate described later tends to improve. The silane coupling agent may be used alone or in combination of two or more types.

[0305] The silane coupling agent is not particularly limited, and any silane coupling agent generally used for surface treatment of inorganic materials can be used. Examples of such silane coupling agents include aminosilane compounds (e.g., 3-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, etc.), epoxysilane compounds (e.g., 3-glycidoxypropyltrimethoxysilane, etc.), acrylicsilane compounds (e.g., γ-acryloxypropyltrimethoxysilane, etc.), vinylsilane compounds (e.g., vinyltrimethoxysilane, etc.), styrylsilane compounds (e.g., p-styryltrimethoxysilane, etc.), cationicsilane compounds (e.g., N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, etc.), and phenylsilane compounds. Among these, it is preferable that the silane coupling agent be one or more selected from the group consisting of epoxysilane compounds and styrylsilane compounds. Examples of epoxysilane compounds include "KBM-403" (trade name), "KBM-303" (trade name), "KBM-402" (trade name), and "KBE-403" (trade name) from Shin-Etsu Chemical Co., Ltd. Examples of styrylsilane compounds include "KBM-1403" (trade name), etc.

[0306] The amount of silane coupling agent is not particularly limited, but may be 0.1 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the total resin solids in the resin composition.

[0307] [Wetting and dispersing agent] The resin composition of this embodiment may also contain a wetting and dispersing agent. When a resin composition contains a wetting and dispersing agent, the dispersibility of the dielectric powder (A), the inorganic filler (B), and any other fillers added as needed is improved, and the adhesive strength between each component of the resin composition and the substrate described later tends to improve. The wetting and dispersing agent may be used alone or in combination of two or more types.

[0308] As a wetting and dispersing agent, known dispersants (dispersion stabilizers) used to disperse fillers can be used. Examples of such wetting and dispersing agents include DISPER BYK®-110, 111, 118, 140, 180, 161, 2009, 2055, 2152, 2155, W969, W996, W9010, and W903 (all trade names) manufactured by BYK Chemie Japan Co., Ltd.

[0309] The content of the wetting and dispersing agent is not particularly limited, but is preferably 0.1 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total resin solids in the resin composition.

[0310] [Curing accelerator] The resin composition of this embodiment may further contain a curing accelerator. The curing accelerator may be used alone or in combination of two or more types.

[0311] Examples of curing accelerators include imidazoles such as triphenylimidazole (e.g., 2,4,5-triphenylimidazole); organic peroxides such as benzoyl peroxide, lauroyl peroxide, acetyl peroxide, parachlorobenzoyl peroxide, and di-tert-butyl-di-perphthalate; azo compounds such as azobisnitrile; N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, 2-N-ethylanilinoethanol, tri-n-butylamine, pyridine, quinoline, N-methylmorpholine, triethanolamine, triethylenediamine, and tetramethyl Examples include tertiary amines such as rubanediamine and N-methylpiperidine; phenols such as phenol, xylenol, cresol, resorcinol, and catechol; organometallic salts such as lead naphthenate, lead stearate, zinc naphthenate, zinc octoate, manganese octoate, tin oleate, dibutyltin maleate, manganese naphthenate, cobalt naphthenate, and iron acetylacetone; compounds obtained by dissolving these organometallic salts in hydroxyl group-containing compounds such as phenol and bisphenol; inorganic metal salts such as tin chloride, zinc chloride, and aluminum chloride; and organotin compounds such as dioctyl tin oxide, other alkyltins, and alkyltin oxides. Among these, triphenylimidazoles such as 2,4,5-triphenylimidazole and manganese octoate are preferred because they promote the hardening reaction and tend to further improve the glass transition temperature.

[0312] The content of the curing accelerator is not particularly limited, but may be 0.001 parts by mass or more and 2 parts by mass or 0.01 parts by mass or more and 1 part by mass per 100 parts by mass of total resin solids in the resin composition.

[0313] 〔solvent〕 The resin composition of this embodiment may further contain a solvent. The inclusion of a solvent in the resin composition tends to lower its viscosity during preparation, further improving its handling properties and impregnation into the substrate. The solvent may be used alone or in combination of two or more types.

[0314] The solvent is not particularly limited as long as it can dissolve some or all of the components in the resin composition. Examples include ketones (acetone, methyl ethyl ketone, etc.), aromatic hydrocarbons (e.g., toluene, xylene, etc.), amides (e.g., dimethylformaldehyde, etc.), propylene glycol monomethyl ether and its acetate.

[0315] [Other ingredients] The resin composition of this embodiment may contain components other than those listed above, as long as the desired properties are not impaired. Examples of other components include flame retardant compounds such as bromine compounds like 4,4'-dibromoviphenyl, nitrogen-containing compounds such as melamine and benzoguanamine, and silicon-based compounds. Examples of various additives include ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent whitening agents, photosensitizers, dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents (surface modifiers), glossing agents, and polymerization inhibitors.

[0316] The content of other components is not particularly limited, but is usually 0.01 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the total resin solids in the resin composition.

[0317] [Method for producing resin compositions] A method for producing the resin composition of this embodiment includes, for example, mixing dielectric powder (A), inorganic filler (B), thermosetting resin (C), and, if necessary, the above-mentioned components, and stirring thoroughly. In this case, known treatments such as stirring, mixing, and kneading can be performed in order to uniformly dissolve or disperse each component. Specifically, by performing a stirring and dispersion treatment using a stirring tank equipped with a stirrer having appropriate stirring capacity, the dispersibility of the dielectric powder (A), inorganic filler (B), and other fillers added as needed in the resin composition can be improved. The above stirring, mixing, and kneading treatments can be appropriately performed using, for example, a device for mixing such as a ball mill or bead mill, or a known device such as a revolving or rotating type mixing device.

[0318] Furthermore, during the preparation of the resin composition, a solvent may be used as needed to prepare a resin varnish. Resin varnishes can be obtained by known methods. For example, a resin varnish can be obtained by adding 10 to 900 parts by mass of an organic solvent to 100 parts by mass of the components of the resin composition excluding the organic solvent, and then performing the known treatments described above (stirring, mixing, kneading, etc.). The type of solvent is not particularly limited as long as it can dissolve the resin in the resin composition. Specific examples are as described above.

[0319] [Application] The resin composition of this embodiment can be suitably used, for example, as a raw material for cured products, prepregs, film-like underfill materials, resin sheets, laminates, build-up materials, non-conductive films, metal foil-clad laminates, printed circuit boards, and fiber-reinforced composite materials, or in the manufacture of semiconductor devices. The resin composition is suitably used for printed circuit boards. These will be described below.

[0320] [Cured product] The cured product of this embodiment includes the resin composition of this embodiment. The cured product is obtained by curing the resin composition. As a method of producing the cured product, for example, the resin composition can be melted or dissolved in a solvent, poured into a mold, and cured under normal conditions using heat, light, etc. In the case of thermal curing, the curing temperature is preferably in the range of 120°C to 300°C from the viewpoint of efficient curing and preventing deterioration of the obtained cured product.

[0321] [Prepreg] The prepreg of this embodiment comprises a substrate and the resin composition of this embodiment impregnated or coated onto the substrate. The prepreg is obtained, for example, by impregnating or coating the substrate with the resin composition (e.g., in an uncured state (stage A)) and then heating and drying it at 120°C to 220°C for 2 to 15 minutes to partially cure it (stage B). In this case, the amount of resin composition (including the cured product of the resin composition) adhering to the substrate, i.e., the amount of resin composition (including conductive powder (A), inorganic filler (B), and other fillers added as needed) relative to the total amount of the partially cured prepreg, is preferably in the range of 20% by mass to 99% by mass. The partially cured state (stage B) refers to a state in which each component contained in the resin composition has not actively started to react (curing), but the resin composition has been heated to the point where it is dry, i.e., non-sticky, and the solvent has been evaporated. This also includes a state in which the solvent has evaporated without curing, even without heating. In this embodiment, the minimum melt viscosity in the semi-cured state (B stage) is typically 20,000 Pa·s or less. The lower limit of the minimum melt viscosity is, for example, 10 Pa·s or more. In this embodiment, the minimum melt viscosity is measured by the following method. That is, 1 g of resin powder taken from the resin composition is used as a sample, and the minimum melt viscosity is measured using a rheometer (ARES-G2 (trade name), TA Instruments). Here, a disposable plate with a plate diameter of 25 mm is used, and the minimum melt viscosity of the resin powder is measured in the range of 40°C to 180°C under conditions of a heating rate of 2°C / min, a frequency of 10.0 rad / sec, and a strain of 0.1%.

[0322] The substrate is not particularly limited as long as it is a substrate used in various printed circuit board materials. Examples of substrate materials include glass fibers (e.g., E-glass, D-glass, L-glass, S-glass, T-glass, Q-glass, UN-glass, and NE-glass, etc.), inorganic fibers other than glass fibers (e.g., quartz, etc.), and organic fibers (e.g., polyimide, polyamide, polyester, liquid crystal polyester, and polytetrafluoroethylene, etc.). The form of the substrate is not particularly limited and includes woven fabrics, nonwoven fabrics, rovings, chopped strand mats, and surfacing mats. These substrates may be used individually or in combination of two or more. Among these substrates, woven fabrics that have undergone ultra-opening treatment and densification treatment are preferred from the viewpoint of dimensional stability, and glass woven fabrics that have been surface-treated with silane coupling agents such as epoxy silane treatment and amino silane treatment are preferred in order to obtain better processability and thermal properties such as moisture absorption and heat resistance. Glass fibers such as E-glass, L-glass, NE-glass, and Q-glass are preferred because they offer superior processability and dielectric properties.

[0323] [Resin sheet] The resin sheet of this embodiment includes the resin composition of this embodiment. The resin sheet may be a resin sheet with a support, comprising a support and a layer formed from the resin composition of this embodiment disposed on the surface of the support. The resin sheet can be used as a build-up film or a dry film solder resist. The method for manufacturing the resin sheet is not particularly limited, but for example, one method is to obtain a resin sheet by applying (coating) a solution obtained by dissolving the resin composition in a solvent onto a support and drying it.

[0324] Examples of supports include, but are not limited to, polyethylene films, polypropylene films, polycarbonate films, polyethylene terephthalate films, ethylene tetrafluoroethylene copolymer films, and release films obtained by coating the surface of these films with a release agent, organic film substrates such as polyimide films, metal foils such as copper foil and aluminum foil, and plate-like materials such as glass plates, SUS plates, and FRP.

[0325] For example, one application method (coating method) involves applying a solution of the resin composition dissolved in a solvent onto a support using a bar coater, die coater, doctor blade, baker applicator, etc. Alternatively, after drying, the support can be peeled off or etched from the support-attached resin sheet, which is formed by laminating the support and the resin composition, to obtain a single-layer sheet (resin sheet). Furthermore, a single-layer sheet (resin sheet) can also be obtained without using a support by supplying a solution of the resin composition dissolved in a solvent into a mold having a sheet-shaped cavity and drying it to form a sheet.

[0326] In the preparation of single-layer sheets or resin sheets with a support, the drying conditions for removing the solvent are not particularly limited, but from the viewpoint of facilitating the removal of the solvent from the resin composition and suppressing the progression of curing during drying, the temperature range is preferably 20°C to 200°C and the drying time is preferably 1 minute to 90 minutes. Furthermore, in single-layer sheets or resin sheets with a support, the resin composition can be used in an uncured state after the solvent has been dried, or it can be used in a semi-cured (B-stage) state as needed. In addition, the thickness of the resin layer of the single-layer sheet or resin sheet with a support can be adjusted by the concentration of the resin composition solution and the coating thickness, and is not particularly limited, but from the viewpoint of facilitating the removal of the solvent during drying, it is preferably 0.1 μm to 500 μm.

[0327] [Laminated board] The laminate of this embodiment includes one or more selected from the group consisting of prepregs and resin sheets of this embodiment. When two or more types of prepregs and resin sheets are laminated, the resin compositions used for each prepreg and resin sheet may be the same or different. Also, when both prepregs and resin sheets are used, the resin compositions used for them may be the same or different. In the laminate, one or more selected from the group consisting of prepregs and resin sheets may be in a semi-cured state (Stage B) or a fully cured state (Stage C).

[0328] [Metal foil-clad laminate] The metal foil-clad laminate of this embodiment includes the laminate of this embodiment and metal foil arranged on one or both sides of the laminate. Furthermore, the metal foil-clad laminate may include at least one prepreg of this embodiment and metal foil laminated on one or both sides of the prepreg. Furthermore, the metal foil laminate may include at least one resin sheet of this embodiment and metal foil laminated on one or both sides of the resin sheet.

[0329] In a metal foil-clad laminate, the resin compositions used for each prepreg and resin sheet may be the same or different, and when both prepregs and resin sheets are used, the resin compositions used for them may be the same or different. In a metal foil-clad laminate, one or more selected from the group consisting of prepregs and resin sheets may be in a semi-cured state or in a fully cured state.

[0330] In metal foil-clad laminates, one or more metal foils selected from the group consisting of prepregs and resin sheets are laminated, but it is preferable that the metal foils are laminated so as to be in contact with the surface of one or more of the materials selected from the group consisting of prepregs and resin sheets. "Laminated so as to be in contact with the surface of one or more of the materials selected from the group consisting of prepregs and resin sheets" means that there is no layer such as an adhesive layer between the prepreg or resin sheet and the metal foil, and the prepreg or resin sheet and the metal foil are in direct contact. As a result, the metal foil peel strength of the metal foil-clad laminate tends to increase, and the insulation reliability of the printed circuit board tends to improve.

[0331] A metal foil-clad laminate may have one or more layers of prepreg and / or resin sheets, and metal foil arranged on one or both sides of the prepreg and / or resin sheets. A method for manufacturing a metal foil-clad laminate includes, for example, a method of laminating one or more layers of prepreg and / or resin sheets, with metal foil arranged on one or both sides. A molding method may include methods commonly used when molding laminates and multilayer boards for printed circuit boards. More specifically, a multi-stage press, multi-stage vacuum press, continuous molding machine, and autoclave molding machine may be used, with a temperature of approximately 180°C to 350°C, a heating time of approximately 100 minutes to 300 minutes, and a surface pressure of 20 kgf / cm². 2 More than 100kgf / cm 2 The following are examples of lamination molding methods.

[0332] Furthermore, a multilayer board can be produced by laminating a prepreg and / or resin sheet with a separately manufactured inner layer wiring board. As a method for manufacturing a multilayer board, for example, copper foil with a thickness of approximately 1.5 μm to 70 μm is placed on both sides of one or more stacked prepreg and / or resin sheets, and the board is laminated using the molding method described above to form a copper foil-clad laminate. After that, an inner layer circuit is formed, and this circuit is subjected to a blackening treatment to form an inner layer circuit board. After that, this inner layer circuit board and prepreg and / or resin sheets are alternately placed one by one, and then copper foil is placed as the outermost layer. A multilayer board can be produced by laminating under the above conditions, preferably under vacuum. Metal foil-clad laminates can be suitably used as printed circuit boards.

[0333] <Metal foil> The metal foil is not particularly limited and includes gold foil, silver foil, copper foil, tin foil, nickel foil, and aluminum foil. Among these, copper foil is preferred. The copper foil is not particularly limited as long as it is generally used as a material for printed circuit boards, but examples include rolled copper foil and electrolytic copper foil. Among these, electrolytic copper foil is preferred from the viewpoint of copper foil peel strength and fine wiring formation. The thickness of the copper foil is not particularly limited and may be about 1.5 μm to 70 μm.

[0334] When copper foil is used as the metal foil, it is preferable that the surface roughness Rz of the copper foil is adjusted to be between 0.2 μm and 4.0 μm. When the surface roughness Rz of the copper foil is 0.2 μm or more, the surface roughness of the copper foil becomes of an appropriate size, and the copper foil peel strength tends to improve further. When the surface roughness Rz of the copper foil is 4.0 μm or less, the surface roughness of the copper foil becomes of an appropriate size, and the dielectric loss tangent of the resulting cured product tends to improve further. The surface roughness Rz is measured in accordance with JIS B0601:2013. Since the copper foil peel strength of the resulting cured product is further improved, the lower limit of the surface roughness Rz of the copper foil is more preferably 0.5 μm or more, even more preferably 0.6 μm or more, and even more preferably 0.7 μm or more. Furthermore, as the dielectric loss tangent of the resulting cured product is further improved, the upper limit of the surface roughness Rz of the copper foil is more preferably 3.5 μm or less, even more preferably 3.0 μm or less, and even more preferably 2.0 μm or less.

[0335] [Printed wiring board] The printed circuit board of this embodiment has an insulating layer and a conductive layer disposed on one or both sides of the insulating layer, wherein the insulating layer contains a cured product of the resin composition of this embodiment. Preferably, the insulating layer contains at least one of a layer formed from the resin composition (a layer containing a cured product) and a layer formed from prepreg (a layer containing a cured product). Such a printed circuit board can be manufactured according to conventional methods, and the manufacturing method is not particularly limited, but for example, it can be manufactured using the metal foil-clad laminate described above. An example of a method for manufacturing a printed circuit board is shown below.

[0336] First, the metal foil-clad laminate described above is prepared. Next, the inner layer circuit is formed by etching the surface of the metal foil-clad laminate to create an inner layer substrate. The inner layer circuit surface of this inner layer substrate is subjected to surface treatment (roughening treatment method) to increase adhesive strength as needed. Then, the required number of prepregs described above are stacked on the inner layer circuit surface, and metal foil for the outer layer circuit is further laminated on the outside, and the two layers are heated and pressed to form an integrated structure. In this way, a multilayer laminate is manufactured in which an insulating layer made of a cured product of the substrate and resin composition is formed between the inner layer circuit and the metal foil for the outer layer circuit. Next, holes for through-holes and via holes are drilled in this multilayer laminate. After that, a plated metal film is formed on the walls of these holes by metal plating treatment to allow conductivity between the inner layer circuit and the metal foil for the outer layer circuit. If necessary, the metal foil for the outer layer circuit is further etched to form the outer layer circuit, thereby manufacturing a printed circuit board. It is preferable to perform a roughening treatment including desmear treatment after drilling holes for through-holes and via holes.

[0337] The printed circuit board obtained in the above manufacturing example has an insulating layer and a conductive layer formed on the surface of the insulating layer, wherein the insulating layer contains a cured resin composition. That is, the prepreg according to this embodiment (including a base material and a cured resin composition of this embodiment impregnated or coated therein), the resin composition layer of the metal foil laminate of this embodiment (a layer containing a cured resin composition of this embodiment) are composed of an insulating layer containing a cured resin composition of this embodiment.

[0338] The resin composition of this embodiment has a high dielectric constant and low dielectric loss tangent, excellent thermal properties such as moisture absorption and heat resistance, and high metal foil peel strength, while also having excellent laser processability. Therefore, by using this resin composition, it is possible to obtain a printed circuit board having an insulating layer with high dielectric constant and low dielectric loss tangent, excellent thermal properties such as moisture absorption and heat resistance, and high metal foil peel strength, while also having higher insulation reliability.

[0339] In the above manufacturing example, one possible method for roughening the surface is to use BO-220 (product name, manufactured by McDermitt Japan Co., Ltd.).

[0340] Drilling holes for through-holes and via holes is typically performed to electrically connect inner and outer layer circuits. A through-hole is a hole that extends from a predetermined position on one surface of a laminate to the other surface of the laminate. A via hole is a hole that extends from a predetermined position on one surface of a laminate to the inner layer circuit, but does not extend to the other surface of the laminate. A predetermined position refers to an appropriate position along the circuit pattern.

[0341] Through-holes and via holes can typically be processed using carbon dioxide (CO2) lasers, mechanical drills, ultraviolet (UV) lasers, and YAG lasers. Among these, carbon dioxide lasers are preferred for drilling through-holes and via holes because they allow for precise processing of small-diameter holes and offer excellent processing speed and cost-effectiveness.

[0342] The top diameters of through-holes and via holes may be different or the same, and are not particularly limited. The top diameters of through-holes and via holes vary depending on the application, but are usually between 1.0 μm and 1000 μm. The top diameter is preferably uniform because it provides excellent mechanical strength and allows for the suitable production of high-density mounted substrates. In this specification, the top diameter refers to the outer diameter of each via hole located furthest from the laser irradiation side.

[0343] Furthermore, carbon dioxide lasers have the advantage of being able to suitably form desired through-holes and via holes by appropriately setting the laser wavelength, pulse width, total energy amount, and number of shots.

[0344] The laser wavelength of a carbon dioxide laser is typically between 9.0 μm and 11.0 μm. A laser wavelength of 9.3 μm is preferred because it prevents gouging of the perforation walls of the laminate and yields a printed circuit board with superior insulation reliability.

[0345] The pulse width of the carbon dioxide laser can be set appropriately depending on the laminate, but is usually 100 μs or less. Preferably, the pulse width is between 1.0 μs and 20 μs. When the pulse width is within the above range, a higher resolution hole shape tends to be obtained. In this specification, pulse width refers to the full width at half maximum in the curve obtained using a single pulse laser. Pulse width has a time dimension and is a temporal width that indicates how long light is emitted.

[0346] The total energy of the carbon dioxide laser per through-hole or via hole is typically between 0.1 mJ and 20 mJ, preferably between 0.5 mJ and 15 mJ. When the total energy is within this range, a finer hole shape tends to be obtained. In this specification, total energy refers to the total amount of laser energy delivered to the printed circuit board in a single laser drilling operation.

[0347] The number of CO2 laser shots per through-hole or via hole is usually between 1 and 5, and preferably between 1 and 3 from the viewpoint of economy and processing time.

[0348] Methods for drilling holes include, for example, trepanning and punching.

[0349] Trepanning is a machining method that creates holes by applying energy along the contour of a hole having a certain shape. In other words, trepanning is a method of machining by cutting the contour of a hole having a certain shape. Trepanning is preferably used when machining holes larger than the beam diameter. In trepanning, the number of shots per revolution is the number of times a single pulse laser is irradiated onto the printed circuit board during one revolution scan when machining a single hole by trepanning. In trepanning, the number of revolutions is the number of revolutions scanned along the contour of the hole when machining a single hole by trepanning.

[0350] Punching is a processing method that involves repeatedly irradiating the same location with a carbon dioxide laser. Punching is preferably used when processing deep holes. In punching, the number of shots refers to the number of times the carbon dioxide laser is irradiated onto the printed circuit board when processing a single hole by punching.

[0351] To remove resin residue remaining on the sides of the formed through-holes and via holes, it is preferable to perform a roughening treatment, including desmearing, after drilling.

[0352] Typically, the roughening process includes a swelling step, a surface roughening and smear dissolution step, and a neutralization step.

[0353] The swelling process involves swelling the surface of the insulating layer using a swelling agent. Examples of swelling agents include those that improve the wettability of the insulating layer's surface and swell the surface of the insulating layer to a degree that promotes oxidative decomposition in the subsequent surface roughening and smear dissolution processes. Examples of such swelling agents include alkaline solutions and surfactant solutions.

[0354] The surface roughening and smear dissolution process is carried out using an oxidizing agent. Examples of oxidizing agents include alkaline permanganate aqueous solutions. Potassium permanganate aqueous solution and sodium permanganate aqueous solution are preferred as such aqueous solutions. Such oxidizing agent treatment is usually called wet desmearing, but in addition to wet desmearing, other known roughening treatments such as oxygen plasma treatment, corona discharge treatment, ultraviolet (UV) laser treatment, and excimer laser treatment for dry desmearing, mechanical polishing with buffs, and sandblasting may be appropriately combined.

[0355] The neutralization step is a step in which the oxidizing agent used in the previous step is neutralized with a reducing agent. Examples of reducing agents include amine-based reducing agents. Preferred reducing agents include acidic aqueous solutions of hydroxylamine sulfate, ethylenediaminetetraacetic acid, and nitrilotriacetic acid.

[0356] It is preferable to perform metal plating after providing through-holes and / or via holes, or after roughening the inside of the through-holes and / or via holes. The metal plating process forms a plated metal film for electrically connecting each conductor layer.

[0357] As for the metal plating method, the metal plating method used in the manufacturing of ordinary multilayer printed circuit boards can be used as appropriate. The metal plating method and the type of chemical solution used for plating can be the same as those used in the manufacturing of ordinary multilayer printed circuit boards. The chemical solution used for metal plating may be a commercially available product.

[0358] Examples of such metal plating methods include treatment with a conditioner solution (degreasing solution), water washing, treatment with a pre-dip solution (soft etching solution), treatment with an electroless plating catalyst solution (activator solution), water washing, treatment with an electroless plating solution (e.g., an electroless copper plating solution), and treatment by immersion in a copper sulfate solution and application of an electric current (copper sulfate electroplating), performed in these order.

[0359] After immersion in copper sulfate solution and application of electric current, drying may be performed. Drying is usually carried out at a temperature between 130°C and 220°C for a period of 10 to 120 minutes.

[0360] [Semiconductor device] A semiconductor device can be manufactured by mounting semiconductor chips on conductive locations in the printed circuit board of this embodiment. Here, conductive locations are locations in the multilayer printed circuit board that transmit electrical signals, and these locations can be on the surface or embedded. Furthermore, the semiconductor chip is not particularly limited as long as it is an electrical circuit element made of semiconductor material.

[0361] The method of mounting semiconductor chips when manufacturing semiconductor devices is not particularly limited as long as the semiconductor chip functions effectively, but specific examples include wire bonding mounting methods, flip-chip mounting methods, bumpless build-up layer (BBUL) mounting methods, anisotropic conductive film (ACF) mounting methods, and non-conductive film (NCF) mounting methods. [Examples]

[0362] The embodiment will be described in more detail below using examples and comparative examples. This embodiment is not limited in any way by the following examples.

[0363] [Measurement method] (1) Relative permittivity (Dk) and dielectric loss tangent (Df) The relative permittivity (Dk) and dielectric loss tangent (Df) of dielectric powders (strontium titanate, spherical calcium titanate, surface-coated titanium oxide, and barium titanate) and inorganic fillers (calcined talc, molten spherical silica, spherical alumina, fine talc powder, and boehmite) were measured by the cavity resonator perturbation method as follows. First, a sample (S) for measurement was obtained by packing 200 mg of dielectric powder into a PTFE (polytetrafluoroethylene) tube (inner diameter: 1.5 mm, manufactured by Nichias Corporation). The relative permittivity (Dk) and dielectric loss tangent (Df) of this sample (S) were measured at a frequency of 10 GHz using a network analyzer (Agilent 8722ES (product name), manufactured by Agilent Technologies, Inc.). The measurements of relative permittivity (Dk) and dielectric loss tangent (Df) were performed under conditions of 23°C ± 1°C and 50% RH (relative humidity) ± 5% RH. Similarly, a PTFE (polytetrafluoroethylene) tube (inner diameter: 1.5 mm, manufactured by Nichias Corporation) was used as sample (B), and the relative permittivity (Dk) and dielectric loss tangent (Df) of sample (B) at a frequency of 10 GHz were measured as a blank. From these measurement results, the relative permittivity (Dk) and dielectric loss tangent (Df) of the dielectric powder at 10 GHz were calculated, respectively, using Bruggeman's equation (ii). Formula (ii): f a ×[(ε a -ε d ) / (ε a +2ε d )]+f b ×[(ε b -ε d ) / (ε b +2ε d )]+f c ×[(ε c -ε d ) / (ε c +2ε d )]=0 Note that in equation (ii), f a This is the volume fraction (vol%) of PTFE in the sample being measured, f b This is the volume fraction (vol%) of air in the sample being measured, f c ε is the volume fraction (vol%) of dielectric powder in the measurement sample. a ε is the complex permittivity of PTFE. b ε is the complex permittivity of air. c ε is the complex dielectric constant of the dielectric powder. d This is the complex permittivity of the sample used for measurement. Specifically, first, in sample (B), the volume fraction f of air bB 46 (vol%), volume fraction f of PTFE aB We assumed it to be 54 (vol%). The complex permittivity is expressed in terms of a real part and an imaginary part, as in "ε = ε' - iε''", and Dk is expressed as ε' and Df as ε'' / ε', so from the measurement results (Dk and Df) of sample (B), we can find the complex permittivity ε of sample (B) (containing PTFE and air). dB Next, the complex permittivity ε of air was calculated. bB Assuming the real part is 1.0 and the imaginary part is 0, then f aB ,f bB , ε dB , and ε bB By substituting this into equation (ii), we obtain the complex dielectric constant ε of PTFE. a The result was calculated. Next, in the measurement sample (S) (including PTFE, air, and dielectric powder), the volume fraction f cS (vol%) of the dielectric powder was calculated using the inner diameter and length of the PTFE tube, the mass difference before and after filling with the dielectric powder, and the specific gravity of the dielectric powder. The volume fraction f aS of PTFE was assumed to be 54 (vol%), and the volume fraction f cS calculated was used to calculate the volume fraction f bS (vol%) of air. Next, in the same manner as for sample (B), the complex dielectric constant ε dS of the sample (S) (including PTFE, air, and dielectric powder) was calculated from the measurement results (Dk and Df) of the measurement sample (S). The complex dielectric constant ε b of air was assumed to be 1.0, and ε a calculated using sample (B), f aS , f bS , f cS , and ε dS were used to calculate the complex dielectric constant ε c of the dielectric powder by equation (ii). The Dk and Df of the dielectric powder were calculated from the calculated ε c .

[0364] (2) Average particle diameter The average particle diameters (D50, μm) of the dielectric powders (strontium titanate, spherical calcium titanate, surface-coated titanium oxide, and barium titanate), and the inorganic fillers (fired talc, fused spherical silica, spherical alumina, fine powder talc, and boehmite) were calculated by measuring the particle size distribution by the laser diffraction / scattering method using a laser diffraction / scattering type particle size distribution measuring device (Microtrac (registered trademark) MT3300EXII (product name), Microtrac Bell Co., Ltd.) based on the following measurement conditions. (Measurement conditions of the laser diffraction / scattering type particle size distribution measuring device) · Strontium titanate... Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 2.41, transmittance: 85 ± 5%. · Spherical calcium titanate... Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 2.41, transmittance: 85 ± 5%. · Titanium dioxide-coated surface… Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 2.72, transmittance: 85 ± 5%. · Barium titanate… Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 2.41, transmittance: 85 ± 5%. · Calcined talc… Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 1.54, transmittance: 85 ± 5%. · Fused spherical silica… Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 1.45, transmittance: 85 ± 5%. · Spherical alumina… Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 1.77, transmittance: 85 ± 5%. · Fine powder talc… Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 1.54, transmittance: 85 ± 5%. · Boehmite… Solvent: methyl ethyl ketone, solvent refractive index: 1.33, particle refractive index: 1.65, transmittance: 85 ± 5%.

[0365] (3) Absorbance at a wavelength of 9.3 μm The absorbances of dielectric powders (strontium titanate, spherical calcium titanate, titanium dioxide-coated surface, and barium titanate), and inorganic fillers (calcined talc, fused spherical silica, spherical alumina, fine powder talc, and boehmite) at a wavelength of 9.3 μm (wave number: 1075 cm -1 ) were measured using the KBr tablet method of Fourier transform infrared spectroscopy as follows. That is, 100 mg of potassium bromide (KBr) powder was weighed for 1 mg of dielectric powder or inorganic filler, and they were ground in a mortar to obtain a mixed powder. The mixed powder was pressure-molded using a hand press and an attached tablet molding machine (Mini Hand Press MHP-1 (trade name) manufactured by Shimadzu Corporation) to obtain a film-like measurement sample. Background measurement was performed without using a sample using a Fourier transform infrared spectrophotometer (IRSpirit (registered trademark), manufactured by Shimadzu Corporation). After that, the obtained measurement sample was loaded into the spectrophotometer, and 500 cm -1 or more and 4000 cm -1The infrared absorption spectrum was obtained as shown below. Using this infrared absorption spectrum, the absorbance at a wavelength of 9.3 μm was obtained. Absorbance is the value expressed as log(I0 / I), where I0 is the incident light intensity and I is the reflected light intensity for the background measurement. Of the obtained infrared absorption spectra, 700 cm⁻¹ -1 More than 1500cm -1 Figure 1 shows the infrared absorption spectra of the dielectric powder (strontium titanate and surface-coated titanium oxide) and inorganic fillers (calcined talc (BST-200L (product name)) from Example 1, molten spherical silica, spherical alumina, fine talc powder, and boehmite) in the following cases.

[0366] (4) Melting point The melting points (°C) of dielectric powders (strontium titanate, spherical calcium titanate, surface-coated titanium oxide, and barium titanate) and inorganic fillers (calcined talc, molten spherical silica, spherical alumina, fine talc powder, and boehmite) were measured using a differential thermogravimetric analyzer as follows: Specifically, the melting points of the dielectric powders or inorganic fillers were measured by using a differential thermogravimetric analyzer (ultra-high temperature thermal analyzer THEMYS®, manufactured by SETARAM Instrumentation) under an argon stream, increasing the temperature from 1000°C to 2000°C in increments of 10°C / min.

[0367] (5) X-ray diffraction The crystalline structures of calcined talc and powdered talc in inorganic fillers were identified using X-ray diffraction (XRD) as follows: Calcined talc or powdered talc was applied to a standard glass sample plate, and X-ray diffraction patterns were obtained under the following measurement conditions. The obtained diffraction patterns were analyzed using integrated powder X-ray analysis software (PDXL2 (product name) manufactured by Rigaku Corporation). By comparing the peak positions and peak intensities of the diffraction patterns with information from a database (ICDD, International Centre for Diffraction Data), the crystalline phases were identified, thereby identifying calcined talc and powdered talc, respectively.

[0368] (Measurement conditions) X-ray diffractometer: Rigaku Corporation MiniFlex® 600 (product name), θ / 2θ scan, tube voltage: 40kV, tube current: 15mA, X-ray source: CuKα (λ=1.54056Å), slit: DS, 0.5°, solar slit: 2.5deg.

[0369] [Synthesis method] The 1-naphthol aralkyl type cyanate ester compound (SN495V-CN) was synthesized as follows. 300 g of 1-naphthol aralkyl type phenolic resin (SN495V (trade name), OH group (hydroxyl group) equivalent: 236 g / eq., Nippon Steel Chemical Co., Ltd.) (1.28 mol in terms of OH groups) and 194.6 g of triethylamine (1.92 mol) (1.5 mol per mol of hydroxyl groups) were dissolved in 1800 g of dichloromethane to prepare Solution 1. 125.9 g of cyanogen chloride (2.05 mol) (1.6 mol per mol of hydroxyl groups), 293.8 g of dichloromethane, 194.5 g of 36% hydrochloric acid (1.92 mol) (1.5 mol per mol of hydroxyl groups), and 1205.9 g of water were added to Solution 1 over 30 minutes while stirring and maintaining the liquid temperature between -2°C and -0.5°C. After adding Solution 1, the mixture was stirred at the same temperature for 30 minutes. Then, Solution 2, a solution of 65 g (0.64 mol) of triethylamine (0.5 mol per 1 mol of hydroxyl groups) dissolved in 65 g of dichloromethane, was added over 10 minutes. After adding Solution 2, the mixture was stirred at the same temperature for 30 minutes to complete the reaction. The reaction mixture was then allowed to stand to separate the organic and aqueous phases, and the resulting organic phase was washed five times with 1300 g of water. The electrical conductivity of the wastewater after the fifth wash was 5 μS / cm, confirming that the ionic compounds that could be removed by washing with water were sufficiently removed. The organic phase after washing with water was concentrated under reduced pressure, and finally concentrated to dryness at 90°C for 1 hour to obtain 331 g of the target 1-naphthol aralkyl type cyanate ester compound (SN495V-CN, cyanate ester group equivalent: 261 g / eq., where all R6 atoms in formula (7) above are hydrogen atoms and n5 is an integer from 1 to 10) (orange viscous substance). The infrared absorption spectrum of the obtained SN495V-CN was obtained at 2250 cm⁻¹. -1 Absorption of the cyanate ester group was observed, but absorption of the hydroxyl group was not.

[0370] [Example 1] As thermosetting resin (C), 25 parts by mass of 1-naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, and as thermosetting resin (C), 25 parts by mass of biphenyl aralkyl type epoxy resin (NC-3000FH (trade name), epoxy equivalent: 328 g / eq., manufactured by Nippon Kayaku Co., Ltd.), and as thermosetting resin (C), biphenyl aralkyl type maleimide compound (MIR-3 50 parts by mass of 000-70MT (product name, Nippon Kayaku Co., Ltd.) and dielectric powder (A) which is strontium titanate (SrTiO3, an oxide with a perovskite structure, average particle size (D50): 0.30 μm, relative permittivity (Dk): 21, dielectric loss tangent (Df): 0.007, absorbance at wavelength 9.3 μm: 0.00, melting point: 2000℃ or higher (reference value: 2080℃, Thermoelectrics based on strontium titanate, Ohta, materialstoday, October 2007, Vol.10 (number10), pp. 44-49 (reference name), ST-03 (product name), manufactured by Sakai Chemical Industry Co., Ltd.) 300 parts by mass, and as an inorganic filler (B), calcined talc (alkaline earth metal silicate having the structure Mg2Si2O6, average particle size (D50): 4.00 μm, relative permittivity (Dk): 5.8, dielectric loss tangent (Df): 0.003, absorbance at wavelength 9.3 μm: 0.78, melting point: 1550℃, BST-200L (product name), A resin varnish was obtained by mixing 50 parts by mass of talc (manufactured by Nippon Talc Co., Ltd.), 3 parts by mass of a wetting and dispersing agent (BYK®-W903 (trade name), manufactured by BYC Chemie Japan Co., Ltd.), 0.1 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.5 parts by mass of manganese octoate (Nikka Octix Manganese (trade name), manufactured by Nippon Chemical Industrial Co., Ltd.), and 100 parts by mass of methyl ethyl ketone. The above proportions other than the solvent are values ​​as solid content. The same applies to other examples and comparative examples.

[0371] The X-ray diffraction pattern of calcined talc (BST-200L (product name)) is shown in Figure 2. In Figure 2, the peaks (diffraction lines) at 2θ of 20, 28, 30, and 31° confirmed that calcined talc is an alkaline earth metal silicate with the structure Mg2Si2O6.

[0372] The obtained resin varnish was impregnated onto a 0.032 mm thick E glass cloth (570 S101S (product name), manufactured by Nitto Denko Corporation), and heated and dried at 130°C for 3 minutes to obtain a prepreg with a thickness of 0.060 mm. Furthermore, the obtained resin varnish was impregnated onto a 0.094 mm thick E glass cloth (1031NT S640 (product name), manufactured by Arisawa Seisakusho Co., Ltd.), and heated and dried at 130°C for 3 minutes to obtain a 0.100 mm thick prepreg. Next, a 12 μm thick electrolytic copper foil (3EC-M3-VLP (product name), manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the top and bottom surfaces of the obtained 0.100 mm thick prepreg, and a surface pressure of 30 kgf / cm² was applied. 2 Furthermore, a metal foil-clad laminate (double-sided copper-clad laminate) with a thickness of 0.124 mm was fabricated by lamination molding using a vacuum press at a temperature of 220°C for 120 minutes. The obtained prepreg with a thickness of 0.060 mm and the metal foil-clad laminate with a thickness of 0.124 mm were used to measure each physical property according to the evaluation method, and the results are shown in Table 1.

[0373] [Example 2] A resin varnish was obtained in the same manner as in Example 1, except that 100 parts by mass of calcined talc (BST-200L (product name)) was added instead of 50 parts by mass as the inorganic filler (B). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 1.

[0374] [Example 3] A resin varnish was obtained in the same manner as in Example 1, except that 30 parts by mass of calcined talc (BST-200L (product name)) was added instead of 50 parts by mass as the inorganic filler (B). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 1.

[0375] [Comparative Example 1] A resin varnish was obtained in the same manner as in Example 1, except that a resin varnish was prepared without using calcined talc (BST-200L (product name)) as the inorganic filler (B). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 1.

[0376] [Comparative Example 2] A resin varnish was obtained in the same manner as in Example 1, except that 50 parts by mass of molten spherical silica (average particle size (D50): 1.10 μm, relative permittivity (Dk): 3.3, dielectric loss tangent (Df): 0.003, absorbance at wavelength 9.3 μm: 0.89, melting point: 1650 °C, SC4053-SQ (product name), manufactured by Admatex Co., Ltd.) was added as the inorganic filler (B) instead of 50 parts by mass of calcined talc (BST-200L (product name)). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 1.

[0377] [Comparative Example 3] A resin varnish was obtained in the same manner as in Example 1, except that 50 parts by mass of spherical alumina (average particle size (D50): 3.50 μm, relative permittivity (Dk): 6.5, dielectric loss tangent (Df): 0.002, absorbance at wavelength 9.3 μm: 0.14, melting point: 2000°C or higher, AX3-15 (product name), manufactured by Micron Division, Nippon Steel Chemical & Material Co., Ltd.) was added as the inorganic filler (B) instead of 50 parts by mass of calcined talc (BST-200L (product name)). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 1.

[0378] [Comparative Example 4] A resin varnish was obtained in the same manner as in Example 1, except that 50 parts by mass of fine talc powder (average particle size (D50): 4.50 μm, relative permittivity (Dk): 5.8, dielectric loss tangent (Df): 0.003, absorbance at wavelength 9.3 μm: 0.55, melting point: 1550 °C, Microace® P4 (trade name), manufactured by Nippon Talc Co., Ltd.) was used as the inorganic filler (B) instead of 50 parts by mass of calcined talc (BST-200L (trade name)).

[0379] Figure 3 shows the X-ray diffraction pattern of fine talc powder (Microace® P4 (product name)). In Figure 3, the peaks (diffraction lines) at 2θ of 10, 19, 28, and 30° indicate that the fine talc powder is Mg3Si4O 10 It was confirmed to be an alkaline earth metal silicate with the structure (OH)2. Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 1.

[0380] [Comparative Example 5] A resin varnish was obtained in the same manner as in Example 1, except that 50 parts by mass of boehmite (average particle size (D50): 1.40 μm, relative permittivity (Dk): 5.9, dielectric loss tangent (Df): 0.003, absorbance at wavelength 9.3 μm: 0.03, melting point: 2000°C or higher, BN-100K (product name), manufactured by Kawai Lime Industry Co., Ltd.) was added as the inorganic filler (B) instead of 50 parts by mass of calcined talc (BST-200L (product name)). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 1.

[0381] [Example 4] A resin varnish was obtained in the same manner as in Example 1, except that instead of 300 parts by mass of strontium titanate (ST-03 (trade name)) as dielectric powder (A), 300 parts by mass of spherical calcium titanate (CaTiO3, an oxide with a perovskite structure, average particle size (D50): 7.00 μm, relative permittivity (Dk): 19, dielectric loss tangent (Df): 0.005, absorbance at a wavelength of 9.3 μm: 0.00, melting point: 1380 °C, spherical calcium titanate (trade name), manufactured by Denka Co., Ltd.) was used as dielectric powder (A). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 2.

[0382] [Example 5] A resin varnish was obtained in the same manner as in Example 1, except that instead of 300 parts by mass of strontium titanate (ST-03 (trade name)) as dielectric powder (A), 300 parts by mass of surface-coated titanium oxide (crystal structure: rutile type, titanium dioxide surface-treated with silica, alumina, and dimethyl silicone (total content of silica, alumina, and dimethyl silicone: 3% by mass), titanium oxide content: 97% by mass, average particle size (D50): 0.21 μm, relative permittivity (Dk): 24, dielectric loss tangent (Df): 0.010, absorbance at wavelength 9.3 μm: 0.00, melting point: 1720 °C, CR-63 (trade name), Ishihara Sangyo Co., Ltd.) was added as dielectric powder (A). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 2.

[0383] [Example 6] A resin varnish was obtained in the same manner as in Example 1, except that instead of 300 parts by mass of strontium titanate (ST-03 (trade name)) as dielectric powder (A), 300 parts by mass of barium titanate (a compound having a structure represented by BaTi4O9, average particle size (D50): 2.10 μm, relative permittivity (Dk): 19, dielectric loss tangent (Df): 0.003, absorbance at wavelength 9.3 μm: 0.00, melting point: 1380℃, BT-149 (trade name), manufactured by Nippon Chemical Industrial Co., Ltd.) was used as dielectric powder (A). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 2.

[0384] [Example 7] A resin varnish was obtained in the same manner as in Example 1, except that instead of 50 parts by mass of calcined talc (BST-200L (product name)) as inorganic filler (B), 50 parts by mass of calcined talc (alkaline earth metal silicate having the structure Mg2Si2O6, average particle size (D50): 1.40 μm, relative permittivity (Dk): 5.8, dielectric loss tangent (Df): 0.003, absorbance at wavelength 9.3 μm: 1.00, melting point: 1550℃, ST-100 (product name), manufactured by Fuji Talc Industry Co., Ltd.) was added as inorganic filler (B).

[0385] Furthermore, when calcined talc (ST-100 (trade name)) was identified using XRD, peaks (diffraction lines) at 2θ of 20, 28, 30, and 31° were observed in the X-ray diffraction pattern. From these peaks, it was confirmed that calcined talc is an alkaline earth metal silicate with the structure Mg2Si2O6.

[0386] Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 2.

[0387] [Comparative Example 6] A resin varnish was obtained in the same manner as in Example 4, except that the varnish was prepared without using calcined talc (BST-200L (product name)) as the inorganic filler (B). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 2.

[0388] [Comparative Example 7] A resin varnish was obtained in the same manner as in Example 5, except that the varnish was prepared without using calcined talc (BST-200L (product name)) as the inorganic filler (B). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 2.

[0389] [Comparative Example 8] A resin varnish was obtained in the same manner as in Example 6, except that the varnish was prepared without using calcined talc (BST-200L (trade name)) as the inorganic filler (B). Using this resin varnish, a 0.060 mm thick prepreg, a 0.100 mm thick prepreg, and a 0.124 mm thick metal foil-clad laminate were obtained in the same manner as in Example 1. The physical properties of the obtained 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate were measured according to the evaluation method, and the results are shown in Table 2.

[0390] [Evaluation Method]

[0391] (1) [Laser processability] Laser processability was evaluated as follows: Using the 0.060 mm thick prepreg and 0.124 mm thick metal foil-clad laminate obtained in the examples and comparative examples, evaluation samples were prepared as follows: One 0.060 mm thick prepreg was laminated on the top and bottom of a 0.124 mm thick metal foil-clad laminate (double-sided copper-clad laminate). Furthermore, ultra-thin copper foil with carrier foil (MicroThin® 18FL (product name), manufactured by Mitsui Mining & Smelting Co., Ltd., carrier foil thickness: 18 μm, ultra-thin copper foil thickness: 1.5 μm) was placed on the top and bottom surfaces, and a surface pressure of 30 kgf / cm² was applied. 2 A metal foil-clad laminate A (double-sided copper-clad laminate A) with a thickness of 0.283 mm was fabricated by lamination molding using a vacuum press at a temperature of 220°C for 120 minutes. After peeling the carrier foil from the obtained metal foil-clad laminate A, via holes for interlayer connection were formed in the metal foil-clad laminate to obtain metal foil-clad laminate B. The via holes were drilled using a laser processing machine for substrate hole drilling (ML605GTWIII-H (product name), carbon dioxide laser, 2 workpiece 2 beam specification, manufactured by Mitsubishi Electric Corporation) under the following conditions: via hole top diameter 80 μm, laser wavelength 9.3 μm, pulse width 15 μs, number of shots 1, and total energy amount 6.5 mJ.

[0392] Next, desmear treatment was performed on metal foil laminate B. First, a swelling solution (an aqueous solution containing the desmear swelling agent UpDess® MDS-37 (product name, manufactured by Uemura Kogyo Co., Ltd.)) was heated to 80°C, and metal foil laminate B was immersed in this aqueous solution for 5 minutes to swell it. Next, a roughening solution (an aqueous solution containing the desmear resin roughening agent MDE-40 (product name, Uemura Kogyo Co., Ltd.) and UpDess® ELC-SH (product name, Uemura Kogyo Co., Ltd.)) was heated to 80°C, and the swollen metal foil laminate B was immersed in this aqueous solution for 10 minutes to roughen the surface and dissolve the smear. Subsequently, the metal foil laminate B, after surface roughening and smear dissolution, was immersed in a neutralizing solution (an aqueous solution containing the desmear neutralizing agent UpDess® MDN-62 (product name, Uemura Kogyo Co., Ltd.)) at room temperature for 5 minutes to neutralize it and obtain laminate A for wiring boards.

[0393] Next, electroless plating was performed on laminate A for wiring boards. First, as a pretreatment for electroless plating, a cleaner conditioner (an aqueous solution containing cleaner MCD-PL (product name, Uemura Kogyo Co., Ltd.)) was heated to 40°C, and laminate A for wiring boards was immersed in this aqueous solution for 5 minutes. After that, it was washed with water to obtain laminate B for wiring boards. Next, laminate B for wiring boards was immersed in a pre-dip solution (an aqueous solution containing alkali palladium ion catalyst pre-dip, Alcup® MDP-2 (product name, Uemura Kogyo Co., Ltd.)) at room temperature for 2 minutes to obtain laminate C for wiring boards. Next, laminate C for wiring boards was immersed in an electroless plating catalyst solution (an aqueous solution containing alkali palladium ion catalyst activator, Alcup® MAT-SP (product name, Uemura Kogyo Co., Ltd.)) at room temperature for 5 minutes. After that, it was washed with water to obtain laminate D for wiring boards. Next, the laminate board D for wiring boards was immersed in an electroless copper plating solution (an aqueous solution containing Surupap® PEA-6-A (product name, Uemura Kogyo Co., Ltd.), Surupap® PEA-6-B (product name, Uemura Kogyo Co., Ltd.), Surupap® PEA-6-C (product name, Uemura Kogyo Co., Ltd.), Surupap® PEA-6-D (product name, Uemura Kogyo Co., Ltd.), and Surupap® PEA-6-E (product name, Uemura Kogyo Co., Ltd.)) at room temperature for 15 minutes to perform electroless plating and obtain laminate board E for wiring boards. Furthermore, laminate board E for wiring boards was subjected to copper sulfate electroplating using a copper sulfate solution to obtain laminate board F for wiring boards.

[0394] Subsequently, the laminated board F for wiring boards was dried at 170°C for 30 minutes to obtain a laminated board G for wiring boards in which a 20 μm thick conductive layer (copper layer) was formed on the surface of the insulating layer.

[0395] The obtained laminated board G for wiring boards was sandwiched between 5 cm thick acrylic plates to obtain laminated board H for wiring boards. Next, using a benchtop polishing machine (ECOMET6 (product name) manufactured by BUEHLER), a sample was cut out along the via holes in laminated board H for wiring boards, so that the cross-section of the via holes could be observed, to obtain an evaluation sample. The cross-section (lateral surface) of the via holes in the evaluation sample was observed using an inverted microscope (EPIPHOT200 (product name), manufactured by Nikon Solutions Corporation) and evaluated according to the following criteria. (Evaluation Criteria) A: In the cross-section of the beer hole, no gouges were observed on the hole wall surface along the fiberglass cloth, or if gouges were observed, the length of the gouges was 2 μm or less. B: In the cross-section of the beer hole, gouges occurred on the hole wall surface along the fibers of the glass cloth, and the length of these gouges was greater than 2 μm and less than or equal to 4 μm. C: In the cross-section of the via hole, gouges occurred on the hole wall surface along the fibers of the glass cloth, and the length of these gouges was greater than 4 μm and less than or equal to 6 μm. D: In the cross-section of the beer hole, gouges occurred on the hole wall surface along the fibers of the glass cloth, and the length of these gouges exceeded 6 μm.

[0396] (2) Copper foil peel strength Five prepregs with a thickness of 0.060 mm obtained in the examples and comparative examples were laminated, and 12 μm thick electrolytic copper foil (3EC-M3-VLP (product name), manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the top and bottom surfaces, with a surface pressure of 30 kgf / cm². 2 A metal foil-clad laminate (double-sided copper-clad laminate) with a thickness of 0.324 mm was fabricated by lamination molding using a vacuum press at 220°C for 120 minutes. The copper foil peel strength (copper foil adhesion, kN / m) was measured using this metal foil-clad laminate (10 mm × 100 mm × 0.324 mm) in accordance with JIS C6481.

[0397] (3) Evaluation of moisture absorption and heat resistance (thermal properties) Five prepregs with a thickness of 0.060 mm obtained in the examples and comparative examples were laminated, and 12 μm thick electrolytic copper foil (3EC-M3-VLP (product name), manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the top and bottom surfaces, with a surface pressure of 30 kgf / cm². 2 A metal foil-clad laminate (double-sided copper-clad laminate) with a thickness of 0.324 mm was fabricated by lamination molding using a vacuum press at a temperature of 220°C for 120 minutes. This metal foil-clad laminate was cut (downsized) to a size of 50 mm × 50 mm × 0.324 mm. Subsequently, the copper foil on one side was completely removed by etching, and on the other copper foil side, half of the copper foil surface was removed by etching to prepare a sample for measurement. Four samples of each type were prepared in the same manner as described above. Each sample was treated for 3 hours at 121°C and 2 atmospheres of saturated water vapor using a pressure cooker tester (PC-3 model (product name), Hirayama Seisakusho Co., Ltd.). After that, the samples were immersed (dipped) in a solder bath at 260°C for 60 seconds, and the presence or absence of abnormal changes in appearance was visually observed and evaluated according to the following criteria. (Evaluation Criteria) A: No abnormalities in appearance were observed in any of the four measurement samples. C: One or more of the four measurement samples showed an abnormal appearance.

[0398] (4) Relative permittivity (Dk) and dielectric loss tangent (Df) Five prepregs with a thickness of 0.060 mm obtained in the examples and comparative examples were laminated, and 12 μm thick electrolytic copper foil (3EC-M3-VLP (product name), manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the top and bottom surfaces, with a surface pressure of 30 kgf / cm². 2A metal foil-clad laminate (double-sided copper-clad laminate) with a thickness of 0.324 mm was fabricated by lamination molding using a vacuum press at 220°C for 120 minutes. The copper foil on both sides of this metal foil-clad laminate was completely etched to obtain an unclad plate with a thickness of 0.300 mm from which all the copper foil had been removed. This unclad plate was cut (downsized) to a size of 1 mm × 65 mm × 0.300 mm to obtain a sample for measurement. Using this sample, the relative permittivity (Dk) and dielectric loss tangent (Df) at a frequency of 10 GHz were measured using a network analyzer (Agilent® 8722ES (product name), manufactured by Agilent Technologies, Inc.). The relative permittivity (Dk) and dielectric loss tangent (Df) measurements were performed under conditions of 23°C ± 1°C and 50% RH ± 5% RH.

[0399] [Table 1]

[0400] [Table 2] [Industrial applicability]

[0401] The resin composition of the present invention has a high dielectric constant and low dielectric loss tangent upon curing, excellent thermal properties such as moisture absorption and heat resistance, excellent laser processability, and high metal foil peel strength. Therefore, the resin composition of the present invention can be suitably used, for example, as a raw material for cured products, prepregs, film-like underfill materials, resin sheets, laminates, build-up materials, non-conductive films, metal foil-clad laminates, printed circuit boards, and fiber-reinforced composite materials, or in the manufacture of semiconductor devices. The resin composition of the present invention is more suitably used in the manufacture of the insulating layer of printed circuit boards.

[0402] This application is based on Japanese Patent Application No. 2023-219669 filed on December 26, 2023, the contents of which are incorporated herein by reference.

Claims

1. A dielectric powder (A) having a relative permittivity of 12.0 or higher at a frequency of 10 GHz, measured according to the cavity resonator perturbation method, and an average particle size (D50) of 0.10 μm or more and 10.00 μm or less, In the infrared absorption spectrum obtained using Fourier transform infrared spectroscopy, the inorganic filler (B) has an absorbance of 0.70 or higher at a wavelength of 9.3 μm, a melting point of 1600°C or lower, and is different from the dielectric powder (A). Thermosetting resin (C) and Including, The dielectric powder (A) contains a titanium-based inorganic filler, The inorganic filler (B) contains an alkaline earth metal silicate having the structure Mg₂Si₂O₆, The content of the dielectric powder (A) is 50 parts by mass or more and 500 parts by mass or less, based on 100 parts by mass of the total resin solids in the resin composition. The amount of the inorganic filler (B) is 10 parts by mass or more and 200 parts by mass or less, based on 100 parts by mass of the total resin solids in the resin composition. Resin composition.

2. The resin composition according to claim 1, wherein the mass ratio ((A):(B)) of the dielectric powder (A) to the inorganic filler (B) is 300:10 to 300:

150.

3. The resin composition according to claim 1, wherein the dielectric loss tangent of the dielectric powder (A) at a frequency of 10 GHz, measured according to the cavity resonator perturbation method, is 0.015 or less.

4. The resin composition according to claim 1, wherein the titanium-based inorganic filler includes at least one selected from the group consisting of surface-uncoated titanium-based inorganic fillers and surface-coated titanium-based inorganic fillers.

5. The resin composition according to claim 4, wherein the surface-uncoated titanium-based inorganic filler comprises at least one selected from the group consisting of titanium monoxide, titanium dioxide, titanium trioxide, potassium titanate, calcium titanate, strontium titanate, barium titanate, aluminum titanate, and lead titanate.

6. The resin composition according to claim 4, wherein the surface-coated titanium-based inorganic filler includes surface-coated titanium oxide.

7. The resin composition according to claim 6, wherein the surface-coated titanium oxide has an organic layer and / or an inorganic oxide layer on the surface of the titanium oxide particles.

8. The average particle size (D50) of the inorganic filler (B) is 0.10 μm or more and 10.00 μm or less. The resin composition according to claim 1.

9. The resin composition according to claim 1, wherein the thermosetting resin (C) comprises one or more selected from the group consisting of maleimide compounds, cyanate ester compounds, epoxy compounds, phenol compounds, modified polyphenylene ether compounds, alkenyl-substituted nadiimide compounds, oxetane resins, benzoxazine compounds, and compounds having polymerizable unsaturated groups.

10. The resin composition according to claim 9, wherein the maleimide compound comprises one or more selected from the group consisting of bis(4-maleimidophenyl)methane, 2,2-bis(4-(4-maleimidophenoxy)-phenyl)propane, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, a maleimide compound represented by the following formula (1), a maleimide compound represented by the following formula (2), a maleimide compound represented by the following formula (3), and a maleimide compound represented by the following formula (4). 【Chemistry 1】 (In formula (1), R 1 Each of these independently represents either a hydrogen atom or a methyl group, and n1 is an integer from 1 to 10. 【Chemistry 2】 (In formula (2), R 2 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and n2 is an average value, where 1 < n2 ≤ 5. 【Transformation 3】 (In formula (3), Ra independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. q is an integer from 0 to 4. If q is an integer from 2 to 4, Ra may be the same or different within the same ring. Rb independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. r is an integer from 0 to 3. If r is 2 or 3, Rb may be the same or different within the same ring. n3 is the average value, ranging from 0.95 to 10.0.) 【Chemistry 4】 (In formula (4), R 1 Each of these independently represents an alkyl group having 1 to 10 carbon atoms. s represents an integer from 1 to 3. R 2 Each of these independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. t represents an integer from 0 to 4. R 3 Each of these independently represents a base represented by the following formula (5). u represents an integer from 0 to 2. 4 R represents a hydrogen atom or a group represented by the following formula (5). 5 n4 represents a hydrogen atom or a group represented by the following formula (6). (n4 represents an integer from 1 to 100.) 【Transformation 5】 (In formula (5), R 6 Each of these independently represents an alkyl group, alkyloxy group, or alkylthio group having 1 to 10 carbon atoms, an aryl group, aryloxy group, or arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. v represents an integer from 0 to 4. *1 indicates the bonding site with a carbon atom. 【Transformation 6】 (In formula (6), R 7 each independently represents an alkyl group having 1 to 10 carbon atoms. w represents an integer of 1 to 3. R 8 each independently represents a group represented by the above formula (5). x represents an integer of 0 to 2. *2 represents a bonding site with a carbon atom.).

11. The resin composition according to claim 9, wherein the cyanate ester compound comprises one or more selected from the group consisting of phenol novolac type cyanate ester compounds, naphthol aralkyl type cyanate ester compounds, naphthylene ether type cyanate ester compounds, xylene resin type cyanate ester compounds, bisphenol M type cyanate ester compounds, bisphenol A type cyanate ester compounds, diallylbisphenol A type cyanate ester compounds, bisphenol E type cyanate ester compounds, bisphenol F type cyanate ester compounds, and biphenyl aralkyl type cyanate ester compounds, as well as prepolymers or polymers of these cyanate ester compounds.

12. The resin composition according to claim 9, wherein the epoxy compound comprises one or more selected from the group consisting of biphenylaralkyl epoxy resins, naphthalene epoxy resins, naphthylene ether epoxy resins, and butadiene skeleton-containing epoxy resins.

13. The resin composition according to claim 1, for use in printed circuit boards.

14. A cured product comprising the resin composition according to any one of claims 1 to 13.

15. Substrate and A prepreg comprising a resin composition according to any one of claims 1 to 13, which is impregnated or coated onto the substrate.

16. A resin sheet comprising the resin composition according to any one of claims 1 to 13.

17. A laminate comprising the prepreg described in claim 15.

18. A laminate comprising the resin sheet described in claim 16.

19. The laminate according to claim 17, A metal foil-clad laminate comprising metal foil arranged on one or both sides of the laminate.

20. The laminate according to claim 18, A metal foil-clad laminate comprising metal foil arranged on one or both sides of the laminate.

21. Insulating layer and, The insulating layer comprises a conductive layer disposed on one or both sides thereof, A printed circuit board in which the insulating layer comprises a cured product of the resin composition described in any one of claims 1 to 13.

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