Resin composition, prepreg, resin sheet, laminate, metal-foil-clad laminate, and printed wiring board

Abstract

This resin composition comprises molybdenum-containing titanium oxide (A), a cyanic acid ester compound (B), and an epoxy compound (C), wherein the functional-group equivalent ratio (cyanato group / epoxy group) of cyanato groups of the cyanic acid ester compound (B) to epoxy groups of the epoxy compound (C) is 0.1-2.0.

Description

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

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

[0002] In recent years, the signal bandwidth of information and communication devices such as mobile phones, as well as the CPU clock time of computers, have reached the GHz range, and higher frequencies are becoming increasingly common. 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 its reliability, it is necessary to select materials with low dielectric constant and 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 various purposes, such as forming delay circuits, impedance matching of wiring boards 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). Insulating layers with high dielectric constant and low dielectric loss tangent are formed by dispersing fillers such as ceramic powder and insulatingly treated metal powder in a resin.

[0004] Furthermore, for the insulating layer, a resin composition using a cyanate ester compound in combination with an epoxy compound is used, for example, because it has excellent heat resistance and electrical properties.

[0005] Japanese Patent Publication No. 2000-91717

[0006] However, increasing the dielectric constant of the insulating layer requires incorporating fillers with a high dielectric constant, but this also increases the dielectric loss tangent, leading to a problem of increased transmission loss of high-frequency signals. Furthermore, increasing the amount of fillers with a high dielectric constant reduces the fluidity of the resin during the insulating layer manufacturing process, causing voids and delamination during the manufacturing of the laminate. This also leads to problems such as deterioration of heat resistance and dielectric properties (high dielectric constant and low dielectric loss tangent) in printed circuit boards and the like. Moreover, insulating layers obtained using epoxy compounds have the problem of insufficient metal foil peel strength (e.g., copper foil peel strength) when used in metal foil-clad laminates.

[0007] The present invention has been made to solve the above 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 low dielectric loss tangent, excellent heat resistance and high metal foil peel strength, as well as a prepreg, resin sheet, laminate, metal foil-clad laminate, and printed circuit board obtained using the resin composition.

[0008] In other words, the present invention is as follows: [1] A resin composition comprising titanium oxide (A) containing molybdenum, a cyanate ester compound (B), and an epoxy compound (C), wherein the functional group equivalent ratio (cyanato group / epoxy group) of the cyanate group of the cyanate ester compound (B) to the epoxy group of the epoxy compound (C) is 0.1 to 2.0.

[0009] [2] The resin composition according to [1], wherein the average particle size of the titanium oxide (A) is 0.1 to 100 μm.

[0010] [3] The resin composition according to [1], wherein the titanium oxide (A) containing molybdenum is molybdenum-doped titanium oxide.

[0011] [4] The resin composition according to any one of [1] to [3], wherein the content of titanium oxide (A) is 50 to 500 parts by mass per 100 parts by mass of the total resin solids in the resin composition.

[0012] [5] The resin composition according to any one of [1] to [4], wherein the cyanate ester compound (B) 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, and biphenyl aralkyl type cyanate ester compounds.

[0013] [6] The resin composition according to any one of [1] to [5], wherein the epoxy compound (C) comprises one or more selected from the group consisting of biphenylaralkyl epoxy resin, naphthalene epoxy resin, naphthylene ether epoxy resin, and butadiene skeleton-containing epoxy resin.

[0014] [7] A resin composition according to any one of [1] to [6], further comprising one or more thermosetting resins or compounds selected from the group consisting of maleimide compounds, modified polyphenylene ether compounds, phenol compounds, alkenyl-substituted nadiimide compounds, oxetane resins, benzoxazine compounds, and compounds having polymerizable unsaturated groups.

[0015] [8] The resin composition according to any one of [1] to [7], further comprising a filler different from titanium oxide (A).

[0016] [9] The resin composition according to [8], wherein the filler comprises one or more selected from the group consisting of silica, alumina, talc, aluminum nitride, boron nitride, boehmite, aluminum hydroxide, zinc molybdate, silicone rubber powder, and silicone composite powder.

[0017]

[10] The resin composition according to [8] or [9], wherein the content of the filler is 50 to 300 parts by mass with respect to 100 parts by mass of the total resin solids in the resin composition.

[0018]

[11] A resin composition according to any one of [1] to

[10] , for use in printed circuit boards.

[0019]

[12] A prepreg comprising a base material and a resin composition according to any one of [1] to

[11] impregnated or coated onto the base material.

[0020] A resin sheet comprising the resin composition described in any one of [1] to

[11] .

[0021] A laminate comprising one or more selected from the group consisting of the prepregs described in

[14] and

[12] and the resin sheets described in

[13] .

[0022] A metal foil-clad laminate comprising the laminate described in

[15] and

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

[0023]

[16] 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 one of the resin compositions described in [1] to

[11] .

[0024] The present invention provides a resin composition suitable for use in manufacturing an insulating layer of a printed circuit board, having a high dielectric constant and low dielectric loss tangent, excellent heat resistance, and high metal foil peel strength, as well as a prepreg, resin sheet, laminate, metal foil-clad laminate, and printed circuit board obtained using the resin composition.

[0025] 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.

[0026] 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 molybdenum-containing titanium oxide (A), dielectric powder, fillers, additives (silane coupling agents, wetting and dispersing agents, curing accelerators, and other components), and solvents. "100 parts by mass of total 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 molybdenum-containing titanium oxide (A), dielectric powder, fillers, additives (silane coupling agents, wetting and dispersing agents, curing accelerators, and other components), and solvents is 100 parts by mass.

[0027] [Resin Composition] The resin composition of this embodiment comprises titanium oxide containing molybdenum (hereinafter also simply referred to as "molybdenum-doped titanium oxide") (A), a cyanate ester compound (B), and an epoxy compound (C), wherein the functional group equivalent ratio (cyanato group / epoxy group) of the cyanate group of the cyanate ester compound (B) and the epoxy group of the epoxy compound (C) is 0.1 to 2.0.

[0028] In this embodiment, if the resin composition comprises molybdenum-doped titanium oxide (A), a cyanate ester compound (B), and an epoxy compound (C), and the functional group equivalent ratio (cyanato group / epoxy group) between the cyanate group of the cyanate ester compound (B) and the epoxy group of the epoxy compound (C) is 0.1 to 2.0, a cured product suitable for the insulating layer of a printed circuit board can be obtained, which has a high dielectric constant and low dielectric loss tangent, excellent heat resistance, and high metal foil peel strength. The reason for this is not clear, but the inventors deduce it as follows.

[0029] Titanium-based inorganic fillers such as titanium dioxide, strontium titanate, and barium titanate, as well as titanium dioxide with a coated surface, typically possess high dielectric constant properties. Furthermore, cured resin compositions using cyanate ester compounds in combination with epoxy compounds exhibit excellent heat resistance and electrical properties.

[0030] However, when using a resin composition containing titanium-based inorganic fillers along with cyanate ester compounds and epoxy compounds, the fluidity of the resin decreases during the process of manufacturing the insulating layer, causing voids to form. This leads to delamination during the manufacturing of laminates, resulting in a tendency for the dielectric properties (high dielectric constant and low dielectric loss tangent) of printed circuit boards and the like to deteriorate. Furthermore, although epoxy compounds have excellent curing properties, an excessive amount of epoxy compound can lead to a decrease in crosslinking density and insufficient curing, resulting in a deterioration of the mechanical properties of the resulting cured product and a decrease in heat resistance. In addition, the peel strength of the metal foil (e.g., copper foil peel strength) when forming a metal foil laminate becomes insufficient. Moreover, the presence of many epoxy groups in the cured product increases the number of polar groups, which tends to cause an increase in the overall dielectric loss tangent of the cured product.

[0031] In contrast, according to the resin composition of this embodiment, which contains molybdenum-doped titanium oxide along with a cyanate ester compound and an epoxy compound in a specific functional group equivalent ratio, the reaction between the cyanate ester compound and the epoxy compound proceeds relatively quickly, resulting in a cured product with excellent heat resistance. Furthermore, since triazine rings and oxazoline rings are formed in the cured product, the insulating layer has high metal foil peel strength. Moreover, because the amount of residual epoxy groups in the resulting cured product is reduced, an increase in dielectric loss tangent is less likely to occur. In addition, molybdenum-doped titanium oxide has a high dielectric constant even in resin compositions such as resin varnishes containing cyanate ester compounds and epoxy compounds. Therefore, it is estimated that the resin composition of this embodiment can produce a cured product and insulating layer with high dielectric constant and low dielectric loss tangent, excellent heat resistance, and high metal foil peel strength.

[0032] <Functional Group Equivalent Ratio> Next, the functional group equivalent ratio will be explained. In the resin composition of this embodiment, the functional group equivalent ratio (cyanato group / epoxy group) between the cyanate group of the cyanate ester compound (B) and the epoxy group of the epoxy compound (C) is 0.1 to 2.0. When the functional group equivalent ratio is within the above range, a high dielectric constant and a low dielectric loss tangent are obtained, and heat resistance and high metal foil peel strength can be achieved simultaneously. A functional group equivalent ratio of 0.2 to 1.8 is preferable, 0.3 to 1.6 is more preferable, 0.5 to 1.5 is even more preferable, and 0.6 to 1.4 is even more preferable, as a higher dielectric constant and a lower dielectric loss tangent result in better heat resistance and higher metal foil peel strength. Furthermore, if the functional group equivalent ratio is less than 0.1, the content of epoxy compound (C) in the resin composition increases, leading to a decrease in crosslinking density and insufficient curing, which tends to result in insufficient metal foil peel strength (e.g., copper foil peel strength) when forming a metal foil laminate. In addition, the presence of many epoxy groups remaining in the cured product increases the number of polar groups, which tends to cause an increase in the overall dielectric loss tangent of the cured product. On the other hand, if the functional group equivalent ratio exceeds 2.0, the content of cyanate ester compound (B) in the resin composition increases, which tends to result in a higher number of polar groups in the cured product. Therefore, it is presumed that the resulting cured product is more likely to absorb moisture from the atmosphere, and the absorbed moisture evaporates during reflow, causing voids to form in the insulating layer, which tends to worsen the heat resistance.

[0033] In this embodiment, the functional group equivalent ratio is the ratio of the equivalent amount of cyanate groups in the cyanate ester compound (B) contained in the resin composition to the equivalent amount of epoxy groups in the epoxy compound (C) contained in the resin composition (hereinafter also referred to as "epoxy equivalent"), and is calculated by the following formula (i). In this embodiment, it is possible to use two or more compounds in either or both of the cyanate ester compound (B) and the epoxy compound (C). In that case, the method for calculating the functional group equivalent ratio is to calculate the number of functional groups (i.e., the equivalent amount of cyanate groups and the equivalent amount of epoxy groups) for each component in the cyanate ester compound (B) and the epoxy compound (C), and then sum these values ​​to calculate the total equivalent amount of cyanate groups and the total equivalent amount of epoxy groups. The functional group equivalent ratio is the value obtained by dividing the total equivalent amount of cyanate groups by the total equivalent amount of epoxy groups. The number of functional groups is the value obtained by dividing the mass parts of the component by the functional group equivalent amount of that component. The epoxy equivalent can be measured in accordance with JIS K7236.

[0034] Formula (i): Functional group equivalent ratio = (Parts by mass of cyanate ester compound (B) in the composition / Functional group equivalent of cyanate ester compound (B)) / (Parts by mass of epoxy compound (C) in the composition / Functional group equivalent of epoxy compound (C))

[0035] Next, we will describe in detail each component contained in the resin composition.

[0036] <Titanium oxide containing molybdenum (A)> The resin composition of this embodiment contains titanium oxide containing molybdenum (molybdenum-doped titanium oxide) (A). Molybdenum-doped titanium oxide (A) is a dielectric powder. Molybdenum-doped titanium oxide (A) may be used alone or in combination of two or more types.

[0037] The shape of the molybdenum-doped titanium oxide (A) is not particularly limited and can be flaky, spherical, plate-like, or amorphous. A spherical shape is preferred because it allows for better compatibility with the cyanate ester compound (B) and epoxy compound (C), resulting in an insulating layer with superior dielectric properties (high dielectric constant and low dielectric loss tangent), superior heat resistance, and superior metal foil peel strength.

[0038] The relative permittivity of molybdenum-doped titanium oxide (A) is preferably 20 or higher, and more preferably 25 or higher. When the relative permittivity is 20 or higher, an insulating layer with a high relative permittivity tends to be obtained. In this embodiment, the relative permittivity of molybdenum-doped titanium oxide (A) is the value measured at 10 GHz by the cavity resonator method. In this embodiment, the relative permittivity of molybdenum-doped titanium oxide (A) can be calculated using the Bruggeman formula (compound rule). For specific measurement methods, please refer to the examples.

[0039] The dielectric loss tangent of molybdenum-doped titanium oxide (A) 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 a low dielectric loss tangent tends to be obtained. In this embodiment, the dielectric loss tangent of molybdenum-doped titanium oxide (A) is the value measured at 10 GHz by the cavity resonator method. In this embodiment, the dielectric loss tangent of molybdenum-doped titanium oxide (A) can be calculated using the Bruggeman formula (compound rule). For specific measurement methods, please refer to the examples.

[0040] The average particle size (D50) of molybdenum-doped titanium oxide (A) is preferably 0.10 to 5.00 μm, and more preferably 0.15 to 3.50 μm, from the viewpoint of dispersibility. In this embodiment, the average particle size (D50) is 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 integration from the smallest particles reaches 50% of the total volume. The average particle size (D50) can be calculated by measuring the particle size distribution using the laser diffraction / scattering method, and specific measurement methods can be found in the examples.

[0041] [Titanium Compounds] The titanium compounds used as raw materials for molybdenum-doped titanium oxide (A) (hereinafter sometimes referred to as precursors) are not particularly limited as long as they can be converted to titanium oxide by heat treatment. Examples of such titanium compounds include titanium chloride, titanium sulfate, metatitaniumic acid, amorphous titanium oxide, anatase-type titanium oxide, rutile-type titanium oxide, and mixed-type titanium oxide of anatase and rutile. The physical form of these precursor titanium compounds, such as shape, particle size, and specific surface area, is not particularly limited.

[0042] Since the shape after firing hardly reflects the shape of the precursor titanium compound, it can be suitably used in any form, such as spherical, amorphous, aspect-defined structures (wires, fibers, ribbons, tubes, etc.), or sheets.

[0043] Similarly, regarding particle size, since the particle size of the precursor titanium compound is hardly reflected, titanium compounds ranging from a few nanometers to several hundred micrometers can be suitably used. Furthermore, the specific surface area of ​​the precursor titanium compound is not particularly limited, and any titanium compound can be suitably used.

[0044] The precursor titanium compound may consist solely of titanium compounds, or it may contain small amounts of metal compounds. For example, aluminum compounds, silicon compounds, zinc compounds, etc., may be present. In order to efficiently form titanium oxide crystals using a molybdenum compound as a flux, the content of these metal compounds in the precursor titanium compound is preferably 20% by mass or less, and more preferably 10% by mass or less.

[0045] In addition, the precursor titanium compound may be a complex of a titanium compound and an organic compound. For example, organic / inorganic composites obtained by modifying titanium oxide with an organic silane, titanium compound composites adsorbed with a polymer, and the like can be suitably used. When using these composites, there is no particular limitation on the content of the organic compound. However, in order to efficiently produce substantially spherical particulate titanium oxide having its own shape, the content is preferably 60% by mass or less, more preferably 30% by mass or less.

[0046] [Molybdenum Compound] In the present embodiment, by sintering the titanium compound in the presence of a molybdenum compound, particulate titanium oxide containing molybdenum can be obtained. In this case, the molybdenum compound is used as a fluxing agent. The molybdenum compound may be molybdenum oxide, or may be an acid radical anion formed by bonding molybdenum metal with oxygen (MO x n- ; hereinafter, M represents a metal).

[0047] The acid radical anion (MO x n- ) is formed by bonding molybdenum metal with oxygen, and the compound containing the acid radical anion is not particularly limited as long as it is a compound that converts to molybdenum oxide at a temperature not higher than the calcination temperature. For example, molybdic acid, H3PMo 12 O 40 , H3SiMo 12 O 40 , NH4Mo7O 12 and the like can be suitably used. Among these, in consideration of cost, it is preferable to use molybdenum oxide. In this case, as the titanium oxide particles are formed, molybdenum oxide sublimates, and most of it can be removed from the reaction system.

[0048] In addition, the acid radical anion formed by bonding molybdenum metal with oxygen (MO x n-As compounds containing ), metal molybdate salts that do not decompose at the calcination temperature can also be used. For example, sodium molybdate, potassium molybdate, lithium molybdate, or mixtures of multiple metal molybdenum salts can be suitably used. In this case, it is necessary to remove the metal molybdate salt after the flux reaction. For example, sodium molybdate, potassium molybdate, and lithium molybdate, which are soluble in water, can be easily removed by washing with water.

[0049] A mixture of a molybdenum compound and a metal compound can also be used as a fluxing agent. In this case, the molybdenum compound and the metal compound are reacted by high-temperature calcination to form a metal molybdate salt. The formed metal molybdate salt is not particularly limited as long as it can form particulate titanium oxide as a fluxing agent. For example, a mixture of molybdenum oxide and lithium carbonate, a mixture of molybdenum oxide and potassium carbonate, or a mixture of molybdenum oxide and sodium carbonate can be suitably used. The molar ratio of molybdenum to metal in the mixture of the molybdenum compound and the metal compound is not particularly limited as long as the desired particulate titanium oxide can be grown, but it is necessary to remove it by washing or other means after the calcination reaction, so it is preferable not to use too much of the metal compound, and it is preferable that the amount of metal compound used is 20 mol% or less of the molybdenum compound.

[0050] The flux containing the molybdenum compound in this embodiment may consist solely of the molybdenum compound, or it may contain other inorganic compounds. For example, it may contain calcium compounds, iron compounds, silicon compounds, etc. In order to efficiently form rutile-type particulate titanium oxide using the molybdenum compound as a flux, the content of these inorganic compounds is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the oxide.

[0051] Furthermore, the flux agent containing the molybdenum compound in this embodiment may be a composite of the molybdenum compound and an organic compound. For example, an organic / inorganic composite obtained by modifying the molybdenum compound with an organosilane, or a molybdenum compound composite with adsorbed polymers, can also be suitably used. When using these composites, there are no particular restrictions on the content of the organic compound, but in order to efficiently form molybdenum-doped titanium oxide (A), the content is preferably 60% by mass or less, and more preferably 30% by mass or less.

[0052] [Castration] The manufacturing method of this embodiment is characterized by forming molybdenum-doped titanium oxide (A), which has excellent dispersibility and is approximately spherical or polyhedral in shape, by calcining a precursor titanium compound in the presence of a molybdenum compound. In this calcination, when the calcination temperature exceeds 700°C, the molybdenum compound functions as a flux and efficiently contributes to the formation of molybdenum-doped titanium oxide (A) with a rutile crystallization rate of 90% or more.

[0053] In the above calcination reaction, the amounts of titanium and molybdenum compounds used are important for obtaining titanium oxide with a high crystallinity, suppressing particle aggregation associated with crystal growth, and efficiently obtaining titanium oxide particles that are roughly spherical or polyhedral, have good dispersibility, and have an average particle diameter of 0.1 to 100 μm. In this case, the molar ratio of titanium atoms in the titanium compound to molybdenum atoms in the molybdenum compound must be in the range of 0.5 to 35.0 for every 1 molybdenum atom, preferably in the range of 1.5 to 20.

[0054] Furthermore, the state of the titanium compound, which is the precursor during firing, and the molybdenum compound, which is the flux, is not particularly limited; they just need to be in the same space where the molybdenum compound can act on the titanium compound. Specifically, even if the two are not mixed, any of the following methods may be used: simple mixing of powders, mechanical mixing using a pulverizer, mixing using a mortar and pestle, etc., and mixing may be done in a dry or wet state.

[0055] Furthermore, the firing temperature should be above the temperature at which the target molybdenum-doped titanium oxide (A) is formed, specifically, a maximum temperature in the range of 700 to 1400°C is acceptable. In particular, to efficiently form molybdenum-doped titanium oxide (A) that is roughly spherical or polyhedral and has a crystallinity of 90% or more, firing at a maximum temperature of 800 to 1200°C is more preferable, and firing in the temperature range of 800 to 1100°C is most preferable.

[0056] Regarding the firing time, it is preferable to raise the temperature to a predetermined maximum temperature within a range of 20 minutes to 10 hours, and to hold the temperature at the maximum firing temperature within a range of 5 minutes to 24 hours. To efficiently form molybdenum-doped titanium oxide (A), it is even more preferable to have a firing and holding time of about 10 minutes to 10 hours.

[0057] The firing atmosphere is not particularly limited; for example, firing can be done in an air or oxygen atmosphere, or in an inert atmosphere such as nitrogen or argon. However, from a cost perspective, an air atmosphere is more preferable.

[0058] The apparatus for firing is not particularly limited, and a so-called firing furnace can be used. Preferably, the firing furnace is made of a material that does not react with sublimated molybdenum oxide, and further, it is preferable to use a highly sealed firing furnace in order to efficiently utilize the molybdenum oxide.

[0059] [Molybdenum-doped titanium oxide (A)] The shape, size, specific surface area, etc. of the molybdenum-doped titanium oxide (A) obtained by the manufacturing method of this embodiment can be controlled by selecting the type and proportion of the precursor titanium compound and molybdenum compound used, as well as the calcination temperature and calcination time.

[0060] Molybdenum-doped titanium oxide (A) is a well-dispersible, self-formed fine particle because it uses a molybdenum compound as a flux. In terms of shape, it can be a nearly spherical polyhedron with flat surfaces, or a roughly spherical shape with smooth spherical surfaces. For example, by lowering the firing temperature or shortening the firing time, the number of flat surfaces of the fine particles can be reduced, and a roughly spherical molybdenum-doped titanium oxide (A) containing many smooth spherical surfaces can be formed. Furthermore, by selecting the flux, it is also possible to form a rod-shaped polyhedron with aspect ratios. For example, when a molybdenum compound containing a metal such as potassium is used as the flux, a rod-shaped polyhedron can be formed.

[0061] The size of molybdenum-doped titanium oxide (A) is in the range of 0.1 to 100 μm in average particle diameter, but particles in the range of 0.5 to 50 μm are particularly preferred. For example, by using molybdenum oxide as a flux at a relatively low calcination temperature, molybdenum-doped titanium oxide (A) with a particle size of 500 nm or less can be formed. By increasing the calcination temperature or by using a metal molybdate salt as a flux, the size of the resulting molybdenum-doped titanium oxide (A) can be increased.

[0062] Comparing the specific surface area of ​​the titanium compound used as a precursor with that of the resulting molybdenum-doped titanium oxide (A), the specific surface area is significantly reduced by calcination. Depending on the flux conditions, the specific surface area of ​​the resulting molybdenum-doped titanium oxide (A) ranges from 0.0001 to 50 m². 2 The range is / g, from 0.001 to 20m 2 Products in the range of / g are preferably obtained.

[0063] The molybdenum compound used as a fluxing agent can be removed during high-temperature firing by sublimation as molybdenum oxide or by washing as a metal molybdate salt. However, some molybdenum that cannot be removed by sublimation or washing is present in molybdenum-doped titanium oxide (A), but its content is 10% by mass or less. In particular, the molybdenum content can be reduced to 1% by mass or less by sufficient firing time and temperature or washing.

[0064] Molybdenum-doped titanium dioxide (A) may be discolored due to its molybdenum content. For example, it tends to turn light gray or yellow when the molybdenum compound content is high.

[0065] The molybdenum compounds in molybdenum-doped titanium oxide (A) are present on the outer surface and inside the titanium oxide particles. These compounds can be reduced by firing or washing at higher temperatures.

[0066] The fact that it is molybdenum-doped titanium oxide (A) can be identified, for example, by crystal structure analysis using X-ray diffraction (XRD) and qualitative and quantitative analysis using X-ray fluorescence (XRF).

[0067] The content of molybdenum-doped titanium oxide (A) is preferably 50 to 500 parts by mass, more preferably 60 to 450 parts by mass, more preferably 70 to 400 parts by mass, and even more preferably 100 to 300 parts by mass, based on 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C). When the content of molybdenum-doped titanium oxide (A) is within the above range, it tends to become even more compatible with the cyanate ester compound (B) and the epoxy compound (C), resulting in an insulating layer having better dielectric properties (high dielectric constant and low dielectric loss tangent), better heat resistance, and better metal foil peel strength.

[0068] The content of molybdenum-doped titanium oxide (A) is preferably 50 to 500 parts by mass, more preferably 60 to 450 parts by mass, more preferably 70 to 400 parts by mass, and even more preferably 100 to 300 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. When the content of molybdenum-doped titanium oxide (A) is within the above range, the molybdenum-doped titanium oxide (A), the cyanate ester compound (B), and the epoxy compound (C) become even more compatible, and an insulating layer with better dielectric properties (high dielectric constant and low dielectric loss tangent), better heat resistance, and better metal foil peel strength tends to be obtained.

[0069] <Dielectric Powder> The resin composition of this embodiment may further contain dielectric powders other than molybdenum-doped titanium oxide (A) and the fillers described later. When the resin composition contains dielectric powder, it is usually 300 parts by mass or less per 100 parts by mass of molybdenum-doped titanium oxide (A). One type of dielectric powder may be used alone, or two or more types may be used in combination.

[0070] The shape of the dielectric powder can be, for example, flaky, spherical, plate-like, or amorphous.

[0071] The relative permittivity of dielectric powder is usually 20 or higher.

[0072] The dielectric loss tangent of dielectric powder is typically 0.015 or less.

[0073] The average particle size (D50) of dielectric powder is typically 0.1 to 5 μm.

[0074] Examples of dielectric powders include titanium oxide (TiO) and barium titanate (e.g., BaTiO). ３、 and BaTi ４ O ９ ), calcium titanate (CaTiO ３ ), strontium titanate (SrTiO ３ ), Titanium trioxide (Ti ２ O ３ ), and titanium dioxide (TiO ２ ) are some examples.

[0075] As for strontium titanate, known types can be used, for example, mainly ABO ３ Examples include oxides with a perovskite structure shown by . Strontium titanate contains (SrO) Ｘ ・TiO ２The compound may contain a structure represented by (0.9 ≤ X < 1.0, 1.0 < X ​​≤ 1.1). In this compound, a portion of Sr may be substituted with another metal element, such as at least one of La (lanthanum), Ba (barium), and Ca (calcium). In addition, in this compound, a portion of Ti may be substituted with another metal element, such as Zr (zirconium).

[0076] Titanium dioxide having a rutile or anatase crystal structure is preferred, and a rutile crystal structure is more preferred.

[0077] Commercially available dielectric powders can be used. Examples of commercially available products include titanium dioxide such as STT-30A and EC-300 from Titanium Industries Co., Ltd., and AEROXIDE (registered trademark, hereinafter the same) TiO from Nippon Aerosil Co., Ltd. ２ T805, and AEROXIDE TiO ２ NKT90 (product name), etc.; as barium titanate, BT-149 (product name) and 208108 (product name) manufactured by Nippon Chemical Industrial Co., Ltd.; as calcium titanate, CT series manufactured by Fuji Titanium Industries Co., Ltd. and spherical calcium titanate (product name) manufactured by Denka Co., Ltd.; as strontium titanate, ST-2 manufactured by Kyoritsu Material Co., Ltd. and ST manufactured by Sakai Chemical Industry Co., Ltd. -03, 396141 manufactured by ALDRICH, ST, HST-1, HPST-1, HPST-2 manufactured by Fuji Titanium Industries Co., Ltd., SW-100, SW-50C, SW-100C, SW-200C, SW-320C, SW-350 manufactured by Titanium Industries Co., Ltd. (all are product names); as titanium trioxide, examples include STR-100A-LP manufactured by Sakai Chemical Industry Co., Ltd. and MT-N1 manufactured by Teika Co., Ltd. (both are product names).

[0078] <Cyanate ester compound (B)> The resin composition of this embodiment contains cyanate ester compound (B). By containing cyanate ester compound (B) and epoxy compound (C) in a specific functional group equivalent ratio, and by containing molybdenum-doped titanium oxide (A), a cured product suitable for the insulating layer of printed circuit boards can be obtained, which has a high dielectric constant and low dielectric loss tangent, excellent heat resistance, and high metal foil peel strength. Cyanate ester compound (B) may be used alone or in combination of two or more types.

[0079] The cyanate ester compound (B) is not particularly limited as long as it is a compound having two or more cyanate groups (also called "cyanate ester groups" or "cyanate groups") directly bonded to two or more aromatic rings in one molecule. Examples of cyanate ester compounds (B) include naphthol aralkyl type cyanate ester compounds, phenol novolac 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, and biphenyl aralkyl type cyanate ester compounds, bis(3,3-dimethyl-4-cyanatophenyl)methane, bis(4-cyanatophenyl)methane, 1,3-disyl Examples include anatobenzene, 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, bis(4-cyanatophenyl) sulfone, and 2,2-bis(4-cyanatophenyl)propane. Among these, the cyanate ester compound (B) preferably contains 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, and biphenyl aralkyl type cyanate ester compounds.

[0080] As the cyanate ester compound (B), naphthol aralkyl type cyanate ester compounds are more preferred because they are more compatible with molybdenum-doped titanium oxide (A), and a cured product with even better dielectric properties (high dielectric constant and low dielectric loss tangent, especially an even higher dielectric constant), even better heat resistance, and even better metal foil peel strength is obtained, and the compound represented by formula (1) is even more preferred.

[0081]

[0082] In formula (1), R ６ Each of these independently represents a hydrogen atom or a methyl group, n ２ n represents an integer greater than or equal to 1. ２ It is preferably an integer between 1 and 20, more preferably an integer between 1 and 10, and even more preferably an integer between 1 and 6.

[0083] These cyanate ester compounds (B) may be produced by known methods. Specific production methods include, for example, the method described in Japanese Patent Application Publication No. 2017-195334 (particularly paragraphs 0052-0057).

[0084] The content of cyanate ester compound (B) is 1 to 99 parts by mass, preferably 5 to 80 parts by mass, more preferably 10 to 70 parts by mass, and even more preferably 30 to 60 parts by mass, based on 100 parts by mass of the total of cyanate ester compound (B) and epoxy compound (C). When the content of cyanate ester compound (B) is within the above range, it tends to mix better with molybdenum-doped titanium oxide (A), resulting in an insulating layer with better dielectric properties (high dielectric constant and low dielectric loss tangent, especially a higher dielectric constant), better heat resistance, and better metal foil peel strength.

[0085] The content of cyanate ester compound (B) is preferably 1 to 99 parts by mass, more preferably 5 to 80 parts by mass, more preferably 10 to 70 parts by mass, and even more preferably 30 to 60 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. When the content of cyanate ester compound (B) is within the above range, it tends to be more compatible with molybdenum-doped titanium oxide (A), resulting in an insulating layer with better dielectric properties (high dielectric constant and low dielectric loss tangent), better heat resistance, and better metal foil peel strength.

[0086] <Epoxy Compound (C)> The resin composition of this embodiment contains epoxy compound (C). By including a cyanate ester compound (B) and epoxy compound (C) in a specific functional group equivalent ratio in the resin composition, and by including molybdenum-doped titanium oxide (A), a cured product suitable for the insulating layer of printed circuit boards can be obtained, which has excellent dielectric properties (high dielectric constant and low dielectric loss tangent), excellent heat resistance, and excellent metal foil peel strength. Any known epoxy compound or resin having one or more epoxy groups in one molecule can be used as appropriate, and the type is not particularly limited. The number of epoxy groups per molecule of epoxy compound (C) is one or more, preferably two or more. The epoxy compound may be used alone or in combination of two or more types.

[0087] As the epoxy compound (C), conventionally known epoxy compounds and epoxy resins can be used. For example, biphenyl aralkyl epoxy resins, naphthalene epoxy resins, bis-naphthalene epoxy resins, polyfunctional phenolic epoxy resins, naphthylene ether 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 resins, naphthol aralkyl Examples include hydroxyl-type epoxy compounds, dicyclopentadiene-type epoxy resins, Zyloc-type epoxy compounds, bisphenol A-type epoxy resins, bisphenol E-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, bisphenol A novolac-type epoxy resins, phenol-type epoxy compounds, biphenyl-type epoxy resins, aralkyl novolac-type epoxy resins, triazine skeleton epoxy compounds, triglycidyl isocyanurates, alicyclic epoxy resins, polyol-type epoxy resins, glycidylamines, glycidyl-type ester resins, butadiene skeleton-containing epoxy 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-containing silicone resins with epichlorohydrin.

[0088] Among these, epoxy compound (C) preferably contains one or more selected from the group consisting of biphenyl aralkyl epoxy resins, naphthalene epoxy resins, naphthylene ether epoxy resins, and butadiene skeleton-containing epoxy resins, as these epoxy compounds react with molybdenum-doped titanium oxide (A) in a more favorable manner, resulting in an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength. Furthermore, these epoxy compounds react with cyanate ester compounds (B) in a more favorable manner, resulting in an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent, especially an even higher dielectric constant), even better heat resistance, and even better metal foil peel strength. Furthermore, because they have a rigid framework and are particularly excellent in heat resistance and dielectric loss tangent, naphthol aralkyl type cyanate ester compounds are preferred as cyanate ester compounds (B) to be used in combination with these epoxy compounds, and the compound represented by formula (1) is more preferred.

[0089] The biphenylaralkyl type epoxy resin is preferably a compound represented by the following formula (2).

[0090]

[0091] In formula (2), ka represents an integer of 1 or more, preferably 1 to 20, and more preferably 1 to 10.

[0092] 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" (NC-3000FH is a compound represented by the above formula (2), in formula (2), where ka is an integer from 1 to 10) from Nippon Kayaku Co., Ltd.

[0093] The naphthalene-type epoxy resin is preferably a compound represented by the following formula (3).

[0094]

[0095] In formula (3), 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).

[0096] Examples of commercially available products of the compound represented by formula (3) above include DIC Corporation's product "EPICLON® EXA-4032-70M" (EXA-4032-70M is where n=0 in formula (3) above, and R ３ｂ (where all are hydrogen atoms), "EPICLON (registered trademark) HP-4710" (in the above formula (3), n=0, R ３ｂ Examples include naphthylmethyl groups containing at least one glycidyloxy group.

[0097] The naphthylene ether type epoxy resin is preferably a bifunctional epoxy compound represented by the following formula (4) or a polyfunctional epoxy compound represented by the following formula (5), or a mixture thereof.

[0098]

[0099] In formula (4), 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).

[0100]

[0101] In formula (5), 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).

[0102] 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 DIC Corporation's "HP-6000", "EXA-7300", "EXA-7310", "EXA-7311", "EXA-7311L", "EXA7311-G3", "EXA7311-G4", "EXA-7311G4S", and "EXA-7311G5", among which "HP-6000" is preferred.

[0103] 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 (6) to (8).

[0104]

[0105] In equation (6), X represents an integer from 1 to 100, and Y represents an integer from 0 to 100.

[0106]

[0107] In formula (7), 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.

[0108]

[0109] In equation (8), e represents an integer between 24 and 35, and f represents an integer between 8 and 11.

[0110] 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" (R-45EPT is a compound with X=50 and Y=0 in formula (6) above) from Nagase ChemteX Corporation, "Epolide® PB3600" and "PB4700" from Daicel Corporation, and "Nisseki Polybutadiene E-1000-3.5" from Nippon Petrochemical Co., Ltd.

[0111] The content of epoxy compound (C) is 1 to 99 parts by mass, preferably 20 to 95 parts by mass, more preferably 30 to 90 parts by mass, and even more preferably 40 to 70 parts by mass, based on 100 parts by mass of the total of cyanate ester compound (B) and epoxy compound (C). When the content of epoxy compound (C) is within the above range, it tends to mix better with molybdenum-doped titanium oxide (A), resulting in an insulating layer with better dielectric properties (high dielectric constant and low dielectric loss tangent), better heat resistance, and better metal foil peel strength.

[0112] The content of epoxy compound (C) is preferably 1 to 99 parts by mass, more preferably 20 to 95 parts by mass, more preferably 30 to 90 parts by mass, and even more preferably 40 to 70 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. When the content of epoxy compound (C) is within the above range, it tends to be more compatible with molybdenum-doped titanium oxide (A), resulting in an insulating layer with better dielectric properties (high dielectric constant and low dielectric loss tangent), better heat resistance, and better metal foil peel strength.

[0113] <Thermosetting Resin or Compound> The resin composition of this embodiment may further contain a thermosetting resin or compound (hereinafter also simply referred to as "thermosetting resin") different from the cyanate ester compound (B) and the epoxy compound (C), as long as it achieves the effects of the present invention. Since the molybdenum-doped titanium oxide (A), the cyanate ester compound (B), and the epoxy compound (C) are made more compatible, an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength can be obtained, examples of thermosetting resins include one or more thermosetting resins or compounds selected from the group consisting of maleimide compounds, modified polyphenylene ether compounds, phenol compounds, alkenyl-substituted nadiimide compounds, oxetane resins, benzoxazine compounds, and compounds having polymerizable unsaturated groups. The thermosetting resin may be used alone or in combination of two or more types.

[0114] As a thermosetting resin, it is preferable to include one or more selected from the group consisting of maleimide compounds, modified polyphenylene ether compounds, phenol compounds, and compounds having polymerizable unsaturated groups, in order to obtain an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength, by further improving the compatibility of molybdenum-doped titanium oxide (A), cyanate ester compounds (B), and epoxy compounds (C).

[0115] The thermosetting resin content is preferably 10 to 150 parts by mass, more preferably 20 to 120 parts by mass, and even more preferably 30 to 100 parts by mass, per 100 parts by mass of the total of the cyanate ester compound (B) and epoxy compound (C), in order to further improve the compatibility of the molybdenum-doped titanium oxide (A), the cyanate ester compound (B), and the epoxy compound (C), and to obtain an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength.

[0116] If the resin composition further contains a thermosetting resin, the lower limit of the total content of the cyanate ester compound (B) and the epoxy compound (C) may be 20 parts by mass or more, preferably 30 parts by mass or more, more preferably 40 parts by mass or more, and even more preferably 50 parts by mass or more, based on 100 parts by mass of the total resin solids in the resin composition. The upper limit of the content may be 100 parts by mass or less, preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and even more preferably 80 parts by mass or less, based on the viewpoint of easily achieving the effects of the present invention.

[0117] (Maleimide Compound) The resin composition of this embodiment may contain a maleimide compound. Any known maleimide compound having one or more maleimide groups in one molecule can be used as appropriate, and the type is not particularly limited. The number of maleimide groups per 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.

[0118] Examples of 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 formula (9), maleimide compounds represented by formula (10), maleimide compounds represented by formula (11), prepolymers of these maleimide compounds, and prepolymers of the above maleimide compounds and amine compounds.

[0119] Among these, it is preferable that the maleimide compound contains 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, maleimide compounds represented by formula (9), maleimide compounds represented by formula (10), and maleimide compounds represented by formula (11). This is because further improving the compatibility of molybdenum-doped titanium oxide (A), cyanate ester compound (B), and epoxy compound (C) results in an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength.

[0120]

[0121] In formula (9), R 1 Each of these independently represents either a hydrogen atom or a methyl group, and n1 is an integer from 1 to 10.

[0122]

[0123] In formula (10), 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 the average value, representing 1 < n2 ≤ 5.

[0124]

[0125] In formula (11), Ra independently represents a hydrogen atom, a C1-C10 alkyl group, an alkyloxy or alkylthio group, a C6-C10 aryl group, an aryloxy or arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. q is an integer from 0 to 4. When q is an integer from 2 to 4, Ra may be the same or different within the same ring. Rb independently represents a hydrogen atom, a C1-C10 alkyl group, an alkyloxy or alkylthio group, a C6-C10 aryl group, an aryloxy or arylthio group, a C3-C10 cycloalkyl group, a halogen atom, a hydroxyl group, or a mercapto group. r is an integer from 0 to 3. When r is 2 or 3, Rb may be the same or different within the same ring. n is the average number of repeating units and represents a value from 0.95 to 10.0.

[0126] In formula (11), Ra is preferably independently a hydrogen atom, a C1-C6 alkyl group, a C3-C6 cycloalkyl group, or a C6-C10 aryl group, and more preferably a C1-C3 alkyl group.

[0127] In formula (11), q is preferably 2 or 3, and more preferably 2.

[0128] In formula (11), it is preferable that all of Rb are hydrogen atoms. It is also preferable that r is an integer from 1 to 3, and Rb is independently a hydrogen atom, a C1-C6 alkyl group, a C3-C6 cycloalkyl group, or a C6-C10 aryl group.

[0129] The maleimide compound content is preferably 10 to 80 parts by mass, more preferably 15 to 70 parts by mass, and even more preferably 20 to 60 parts by mass, based on 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C). By having the maleimide compound content within the above range, the molybdenum-doped titanium oxide (A), the cyanate ester compound (B), and the epoxy compound (C) are made even more compatible, and an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength tends to be obtained.

[0130] The maleimide compound content is preferably 10 to 80 parts by mass, more preferably 15 to 70 parts by mass, and even more preferably 20 to 60 parts by mass, based on 100 parts by mass of the total resin solids in the resin composition. By having the maleimide compound content within the above range, the molybdenum-doped titanium oxide (A), the cyanate ester compound (B), and the epoxy compound (C) are made even more compatible, and an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength tends to be obtained.

[0131] 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", "BMI-80", and "BMI-1000P" from K.I. Chemicals Co., Ltd., "BMI-3000", "BMI-4000", "BMI-5100", "BMI-7000", and "BMI-2300" (maleimide compound represented by formula (9) above) from Yamato Chemical Industries, Ltd., "MIR-3000-MT" (maleimide compound represented by formula (10) above) from Nippon Kayaku Co., Ltd., and "NE-X-9470S" (maleimide compound represented by formula (11) above) from DIC Corporation.

[0132] (Modified Polyphenylene Ether Compound) The resin composition of this embodiment may also contain a modified polyphenylene ether compound. The modified polyphenylene ether compound is not particularly limited and any known compound can be used as appropriate, as long as some or all of the ends of the polyphenylene ether compound are modified. The modified polyphenylene ether compound may be used alone or in combination of two or more types.

[0133] 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 (12), the structural unit represented by formula (13), and the structural unit represented by formula (14).

[0134]

[0135] In formula (12), R8, R9, R 10 , and R 11 Each of these independently represents an alkyl group, aryl group, halogen atom, or hydrogen atom having six or fewer carbon atoms.

[0136]

[0137] In formula (13), R 12 , R 13 , R 14 , R 18 , R 19 Each of these independently represents an alkyl group or phenyl group having 6 or fewer carbon atoms. 15 , R 16 , R 17 Each of these independently represents a hydrogen atom, an alkyl group having six or fewer carbon atoms, or a phenyl group.

[0138]

[0139] In formula (14), R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27Each of these independently represents a hydrogen atom, an alkyl group having 6 or fewer carbon atoms, or a phenyl group. -A- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or fewer carbon atoms.

[0140] Examples of -A- in formula (14) 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.

[0141] As modified polyphenylene ether compounds, for example, modified polyphenylene ether compounds having functional groups such as ethylenically unsaturated groups like vinylbenzyl groups, epoxy groups, amino groups, hydroxyl groups, mercapto groups, carboxyl groups, methacrylic groups, and silyl groups at some or all of the terminal ends of the polyphenylene ether compound are preferred.

[0142] Examples of modified polyphenylene ether compounds with hydroxyl groups at the end include SA90 (trade name) manufactured by SABIC Innovative Plastics. Examples of polyphenylene ethers with methacrylic groups at the end include SA9000 (trade name) manufactured by SABIC Innovative Plastics.

[0143] The method for producing the modified polyphenylene ether compound is not particularly limited as long as it achieves the effects of the present invention. For example, it can be produced by the method described in Japanese Patent No. 4591665.

[0144] Modified polyphenylene ether compounds may include modified polyphenylene ether compounds having ethylenically unsaturated groups at their terminal ends. Examples of ethylenically unsaturated groups include alkenyl groups such as ethenyl, allyl, acrylic, methacrylic, propenyl, butenyl, hexenyl, and octenyl groups; cycloalkenyl groups such as cyclopentenyl and cyclohexenyl groups; and alkenylaryl groups such as vinylbenzyl and vinylnaphthyl groups. The terminal ethylenically unsaturated groups may be single or multiple, and may be the same functional group or different functional groups.

[0145] By further improving the compatibility of molybdenum-doped titanium oxide (A), cyanate ester compound (B), and epoxy compound (C), an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength can be obtained. Therefore, as the modified polyphenylene ether compound having ethylenically unsaturated groups at its ends, the compound represented by formula (15) is preferred.

[0146]

[0147] In formula (15), X represents an aromatic group, and -(Y-O) m The dash (-) indicates the 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. n is preferably an integer from 1 to 4, more preferably 1 or 2, and ideally 1. q is preferably an integer from 1 to 3, more preferably 1 or 2, and ideally 2.

[0148] The aromatic group represented by X in formula (15) 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). 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.

[0149] In formula (15), the polyphenylene ether portion can be the structural unit represented by formula (12), the structural unit represented by formula (13), and the structural unit represented by formula (14).

[0150] Among the modified polyphenylene ether compounds, those represented by formula (16) below are preferred.

[0151]

[0152] In formula (16), X is an aromatic group, and -(Y-O) m The hyphens indicate the polyphenylene ether portion, and m is an integer from 1 to 100. m is preferably an integer between 1 and 50, and more preferably an integer between 1 and 30. In formula (16), X, -(Y-O) m - and m are equivalent to those in equation (15).

[0153] In equations (15) and (16), X is equation (17), equation (18), or equation (19), and in equations (15) and (16), -(Y-O) m - and - (O - Y) m- may be a structure in which formula (20) or formula (21) is arranged in sequence, or a structure in which formula (20) and formula (21) are arranged in a block or randomly.

[0154]

[0155]

[0156] In formula (18), 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 having 20 or fewer carbon atoms. Specific examples of -B- are the same as the specific examples of -A- in formula (14).

[0157]

[0158] In formula (19), -B- is a linear, branched, or cyclic divalent hydrocarbon group having 20 or fewer carbon atoms. Specific examples of -B- are the same as the specific examples of -A- in formula (14).

[0159]

[0160]

[0161] The method for producing a modified polyphenylene ether compound having the structure represented by formula (16) is not particularly limited. 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. Commercially available modified polyphenylene ether compounds can also be used. For example, OPE-2St1200 and OPE-2st2200 manufactured by Mitsubishi Gas Chemical Co., Ltd. can be suitably used.

[0162] The content of the modified polyphenylene ether compound is preferably 1 to 50 parts by mass per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C).

[0163] The content of the modified polyphenylene ether compound is preferably 1 to 50 parts by mass per 100 parts by mass of the total resin solids in the resin composition.

[0164] (Phenol Compounds) The resin composition of this embodiment may contain phenol compounds. Any known phenol compound having two or more phenolic hydroxyl groups in one molecule can be used as appropriate, and the type is not particularly limited. One type of phenol compound may be used alone, or two or more types may be used in combination.

[0165] Examples of phenol compounds include cresol novolac type phenol resins, biphenyl aralkyl type phenol resins represented by formula (22), naphthol aralkyl type phenol resins represented by formula (23), aminotriazine novolac type phenol resins, naphthalene type phenol resins, phenol novolac resins, alkylphenol novolac resins, bisphenol A type novolac resins, dicyclopentadiene type phenol resins, Zyloc type phenol resins, terpene-modified phenol resins, and polyvinylphenols.

[0166] Among these, cresol novolac type phenol resin, biphenyl aralkyl type phenol resin represented by formula (22), naphthol aralkyl type phenol resin represented by formula (23), aminotriazine novolac type phenol resin, and naphthalene type phenol resin are preferred.

[0167]

[0168] In formula (22), R 4 Each of these independently represents a hydrogen atom or a methyl group, n ４ The integer is between 1 and 10.

[0169]

[0170] In formula (23), R 5 Each of these independently represents a hydrogen atom or a methyl group, n ５ The integer is between 1 and 10.

[0171] The phenol compound content is preferably 1 to 50 parts by mass per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C).

[0172] The phenol compound content is preferably 1 to 50 parts by mass per 100 parts by mass of the total resin solids of the resin composition.

[0173] (Alkenyl-substituted nadiimide compounds) The resin composition of this embodiment may also contain alkenyl-substituted nadiimide compounds. 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.

[0174] Examples of alkenyl-substituted nadiimide compounds include the compound represented by the following formula (24).

[0175]

[0176] In formula (24), R1 independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (for example, 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 (25) or formula (26) having 1 to 6 carbon atoms.

[0177]

[0178] In formula (25), R3 represents a methylene group, an isopropylidene group, CO, O, S, or SO2.

[0179]

[0180] In formula (26), R4 independently represents either an alkylene group having 1 to 4 carbon atoms or a cycloalkylene group having 5 to 8 carbon atoms.

[0181] The alkenyl-substituted nadiimide compound represented by formula (24) 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" from Maruzen Petrochemical Co., Ltd.

[0182] The content of the alkenyl-substituted nadiimide compound is preferably 1 to 50 parts by mass per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C).

[0183] The content of the alkenyl-substituted nadiimide compound is preferably 1 to 50 parts by mass per 100 parts by mass of the total resin solids in the resin composition.

[0184] (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.

[0185] 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 (Toagosei Co., Ltd., trade name), and OXT-121 (Toagosei Co., Ltd., trade name).

[0186] The oxetane resin content is preferably 1 to 50 parts by mass per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C).

[0187] The oxetane resin content is preferably 1 to 50 parts by mass per 100 parts by mass of the total resin solids in the resin composition.

[0188] (Benzoxazine Compound) The resin composition of this embodiment may contain a benzoxazine compound. The benzoxazine compound is not particularly limited as long as it has two or more dihydrobenzoxazine rings in one molecule, and generally known compounds can be used. The benzoxazine compound may be used alone or in combination of two or more.

[0189] Examples of benzoxazine compounds include bisphenol A type benzoxazine BA-BXZ (Konishi Chemical Industry Co., Ltd., trade name), bisphenol F type benzoxazine BF-BXZ (Konishi Chemical Industry Co., Ltd., trade name), and bisphenol S type benzoxazine BS-BXZ (Konishi Chemical Industry Co., Ltd., trade name).

[0190] The content of the benzoxazine compound is preferably 1 to 50 parts by mass per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C).

[0191] The content of the benzoxazine compound is preferably 1 to 50 parts by mass per 100 parts by mass of the total resin solids in the resin composition.

[0192] (Compounds having polymerizable unsaturated groups) The resin composition of this embodiment may contain compounds having polymerizable unsaturated groups. The compounds having polymerizable unsaturated groups are not particularly limited and generally known compounds can be used. The compounds having polymerizable unsaturated groups may be used individually or in combination of two or more.

[0193] 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.

[0194] The content of the polymerizable unsaturated compound is preferably 1 to 50 parts by mass per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C).

[0195] The content of the polymerizable unsaturated compound is preferably 1 to 50 parts by mass per 100 parts by mass of the total resin solids in the resin composition.

[0196] <Filler> By further improving the compatibility of molybdenum-doped titanium oxide (A), cyanate ester compound (B), and epoxy compound (C), an insulating layer with even better dielectric properties (high dielectric constant and low dielectric loss tangent), even better heat resistance, and even better metal foil peel strength can be obtained. Therefore, the resin composition of this embodiment may further contain a filler different from molybdenum-doped titanium oxide (A) and dielectric powder. The filler is not particularly limited as long as it is different from molybdenum-doped titanium oxide (A) and dielectric powder. The filler may be used alone or in combination of two or more types.

[0197] The relative permittivity of the filler other than molybdenum-doped titanium oxide (A) and dielectric powder is preferably less than 20, and more preferably 15 or less. In this embodiment, the relative permittivity of the filler can be measured and calculated in the same way as for molybdenum-doped titanium oxide (A) described above.

[0198] The average particle size (D50) of the filler is preferably 0.10 to 10.0 μm, and more preferably 0.30 to 5.0 μm. The average particle size (D50) of the filler is calculated in the same manner as the average particle size (D50) of the molybdenum-doped titanium oxide (A) described above.

[0199] Examples of fillers include silica, silicon compounds (e.g., white carbon), metal oxides (e.g., alumina), and molybdenum compounds (e.g., molybdic acid, ZnMoO). ４ and Zn ３ Mo ２ O ９Zinc molybdate, ammonium molybdate, sodium molybdate, potassium molybdate, calcium molybdate, molybdenum disulfide, molybdenum trioxide, molybdate hydrate, (NH ４ ) Zn ２ Mo ２ O ９ ・(H ３ O) Zinc ammonium molybdate hydrate, zinc oxide, magnesium oxide, and zirconium oxide, etc.), metal nitrides (e.g., boron nitride, silicon nitride, and aluminum nitride, etc.), metal sulfides (e.g., barium sulfate, etc.), 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, etc.), zinc compounds (e.g., zinc borate and zinc stannate, etc.), clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, E-glass, A-glass, NE-glass, C-glass, L-glass, D- Examples of fillers include glass, S-glass, M-glass G20, glass short fibers (including glass powders such as E-glass, T-glass, D-glass, S-glass, and Q-glass), hollow glass, spherical glass, and 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 system, Ni-Zn system, Mn-Zn system, carbonyl iron, Fe-Si system, Fe-Al-Si system, and Fe-Ni system; organic fillers such as rubber powders of the styrene type, butadiene type, and acrylic type; core-shell type rubber powder; silicone resin powder; silicone rubber powder; and silicone composite powder.

[0200] Among these, the filler preferably contains one or more selected from the group consisting of silica, alumina, talc, aluminum nitride, boron nitride, boehmite, aluminum hydroxide, zinc molybdate, silicone rubber powder, and silicone composite powder, and more preferably contains silica and / or zinc molybdate.

[0201] The filler may be a surface-treated filler in which an inorganic oxide is formed on at least a part of the surface of filler core particles. Examples of such a filler include surface-treated molybdenum compound particles (supported type) in which an inorganic oxide is formed on at least a part of the surface of core particles made of a molybdenum compound. The inorganic oxide only needs to be provided on at least a part of the surface of the filler core particles. The inorganic oxide may be partially provided on the surface of the filler core particles, or may be provided so as to cover the entire surface of the filler core particles. From the viewpoint of obtaining an insulating layer having more excellent dielectric properties (high dielectric constant and low dielectric loss tangent), more excellent heat resistance, and more excellent metal foil peel strength, it is preferable that the inorganic oxide is uniformly provided so as to cover the entire surface of the filler core particles, that is, a coating film of the inorganic oxide is uniformly formed on the surface of the filler core particles.

[0202] Examples of the surface-treated molybdenum compound particles (supported type) include those obtained by surface-treating molybdenum compound particles with a silane coupling agent, and those obtained by treating the surface with an inorganic oxide by a method such as a sol-gel method or a liquid phase deposition method.

[0203] As the inorganic oxide, those excellent in heat resistance are preferable, and although the type thereof is not particularly limited, metal oxides are more preferable. Examples of the metal oxide include SiO ２ , Al ２ O ３ , TiO ２ , ZnO, In ２ O ３ , SnO ２ , NiO, CoO, V ２ O ５ , CuO, MgO, and ZrO ２ and the like. These may be used alone or in appropriate combination of two or more thereof. Among these, from the viewpoints of heat resistance, insulating properties, cost, etc., silica (SiO ２ ), titania (TiO ２ ), alumina (Al ２ O ３ ), and zirconia (ZrO ２ ) are preferable.

[0204] 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 at least one selected from the group consisting of molybdic acid, zinc molybdate, and zinc ammonium molybdate hydrate.

[0205] The thickness of the inorganic oxide on the surface can be set appropriately according to the desired performance and is not particularly limited. However, it is preferable that the thickness be 3 to 500 nm, as this allows for the formation of a uniform inorganic oxide film, resulting in better adhesion to the filler core particles, and an insulating layer with superior dielectric properties (high dielectric constant and low dielectric loss tangent), superior heat resistance, and superior metal foil peel strength.

[0206] The average particle size (D50) of the surface-treated molybdenum compound particles is preferably 0.1 to 10 μm from the viewpoint of dispersibility in the resin composition. The average particle size (D50) of the surface-treated molybdenum compound particles is calculated in the same manner as the average particle size (D50) of the molybdenum-doped titanium oxide (A) described above.

[0207] 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.

[0208] 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.

[0209] 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 film 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 film 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 film of silica or alumina on the surface of the molybdenum compound.

[0210] The filler content is preferably 50 to 300 parts by mass per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C). The filler content is preferably 50 to 300 parts by mass per 100 parts by mass of the total resin solids in the resin composition. If two or more types of fillers are included, the total amount should be within the above range.

[0211] <Silane Coupling Agent> The resin composition of this embodiment may further contain a silane coupling agent. By containing a silane coupling agent, the dispersibility of molybdenum-doped titanium oxide (A) in the resin composition, as well as dielectric powders and fillers added as needed, is further improved, and the adhesive strength between each component in the resin composition and the substrate described later tends to be further improved. The silane coupling agent may be used alone or in combination of two or more types.

[0212] 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 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.), cationic silane compounds (e.g., N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, etc.), styrylsilane compounds, phenylsilane compounds, etc. The silane coupling agent can be used alone or in combination of two or more. Among these, epoxysilane compounds and styrylsilane compounds are preferred as the silane coupling agent. 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.

[0213] The content of the silane coupling agent is not particularly limited, but may be 0.1 to 5.0 parts by mass per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C). The content of the silane coupling agent is not particularly limited, but may be 0.1 to 5.0 parts by mass per 100 parts by mass of the total resin solids in the resin composition.

[0214] <Wetting and Dispersing Agent> The resin composition of this embodiment may further contain a wetting and dispersing agent. By containing a wetting and dispersing agent, the resin composition tends to have improved dispersibility of molybdenum-doped titanium oxide (A), and the dielectric powder and fillers that are optionally added. The wetting and dispersing agent may be used alone or in combination of two or more types.

[0215] Any known dispersant (dispersion stabilizer) used to disperse fillers may be used as a wetting and dispersing agent. Examples include DISPER BYK®-110, 111, 118, 180, 161, 2009, 2152, 2155, W996, W9010, and W903 (all trade names) manufactured by BIC Chemie Japan Co., Ltd.

[0216] The content of the wetting and dispersing agent is not particularly limited, but it is preferably 0.5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C). The content of the wetting and dispersing agent is not particularly limited, but it is preferably 0.5 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the total of the resin solids in the resin composition.

[0217] <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.

[0218] 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 tetramethylbutamine. Examples include tertiary amines such as diamine 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.

[0219] The content of the curing accelerator is not particularly limited, but it is preferably 0.001 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the total of the cyanate ester compound (B) and the epoxy compound (C). The content of the curing accelerator is not particularly limited, but it is preferably 0.001 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the total of the resin solids in the resin composition.

[0220] <Solvent> The resin composition of this embodiment may further contain a solvent. By including a solvent, the viscosity of the resin composition during preparation tends to decrease, further improving handling properties and further improving impregnation into the substrate. One type of solvent may be used alone, or two or more types may be used in combination.

[0221] 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.

[0222] <Other Components> The resin composition of this embodiment may contain components other than those listed above, as long as the desired properties are not impaired. For example, flame retardant compounds include bromine compounds such as 4,4'-dibromoviphenyl, phosphate esters, melamine phosphate, nitrogen-containing compounds such as melamine and benzoguanamine, and silicon-based compounds. Various additives include ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent whitening agents, photosensitizers, dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents (surface modifiers), glossing agents, polymerization inhibitors, and the like.

[0223] 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 of cyanate ester compound (B) and epoxy compound (C). 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 of resin solids in the resin composition.

[0224] [Method for Manufacturing the Resin Composition] The method for manufacturing the resin composition of this embodiment is not particularly limited, but for example, one method involves mixing molybdenum-doped titanium oxide (A), a cyanate ester compound (B), an epoxy compound (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 an appropriate stirring capacity, the dispersibility of molybdenum-doped titanium oxide (A) in the resin composition, as well as the dielectric powder and filler added as necessary, 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 a bead mill, or a known device such as an orbital or rotational type mixing device.

[0225] Furthermore, when preparing the resin composition, a solvent may be used as needed to prepare it as a resin varnish. 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. Resin varnish can usually be obtained by adding 10 to 900 parts by mass of solvent to 100 parts by mass of the components of the resin composition excluding the solvent, and then performing the known treatments described above (stirring, mixing, kneading, etc.).

[0226] [Applications] The resin composition of this embodiment can be suitably used 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, fiber-reinforced composite materials, or in the manufacture of semiconductor devices. These will be described below.

[0227] [Cured product] The cured product is obtained by curing the resin composition of this embodiment. As a method of producing the cured product, for example, the resin composition of this embodiment can be melted or dissolved in a solvent, poured into a mold, and cured under normal conditions using heat or light. In the case of thermal curing, the curing temperature is preferably in the range of 120 to 300°C from the viewpoint of efficient curing and prevention of deterioration of the resulting cured product.

[0228] [Prepreg] The prepreg of this embodiment comprises a substrate and the resin composition of this embodiment impregnated or coated onto the substrate. The prepreg of this embodiment can be obtained, for example, by impregnating or coating the substrate with the resin composition of this embodiment (for example, in an uncured state (A stage)), and then partially curing it by drying it at 100 to 220°C for about 2 to 15 minutes, preferably at 120 to 220°C for about 2 to 15 minutes. 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 molybdenum-doped titanium oxide (A), and dielectric powder and fillers as needed) relative to the total amount of prepreg after partial curing, is preferably in the range of 20 to 99% by mass.

[0229] 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, NE-glass, and spherical glass), inorganic fibers other than glass fibers (e.g., quartz), and organic fibers (e.g., polyimide, polyamide, polyester, liquid crystal polyester, and polytetrafluoroethylene). 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 surface-treated with silane coupling agents such as epoxy silane treatment and amino silane treatment are preferred because they provide an insulating layer with superior dielectric properties (high dielectric constant and low dielectric loss tangent), superior heat resistance, and superior metal foil peel strength. Glass fibers such as E-glass, L-glass, NE-glass, and Q-glass are preferred due to their excellent dielectric properties.

[0230] [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, which includes 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, a method of obtaining a resin sheet can be obtained by applying (coating) a solution obtained by dissolving the resin composition of this embodiment in a solvent to a support and drying it.

[0231] 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, conductive foils such as copper foil and aluminum foil, and plate-like materials such as glass plates, SUS plates, and FRP.

[0232] As for the coating method, for example, a solution obtained by dissolving the resin composition of this embodiment in a solvent is applied to 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 in which the support and the resin composition are laminated to form 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 obtained by dissolving the resin composition of this embodiment in a solvent into a mold having a sheet-shaped cavity and drying it to form a sheet.

[0233] In the production of the single-layer sheet or resin sheet with support according to this embodiment, 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, a temperature of 20 to 200°C for 1 to 90 minutes is preferred. Furthermore, in the single-layer sheet or resin sheet with 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. Moreover, the thickness of the resin layer in the single-layer sheet or resin sheet with support according to this embodiment can be adjusted by the concentration of the solution of the resin composition of this embodiment and the coating thickness, and is not particularly limited, but from the viewpoint of facilitating the removal of the solvent during drying, 0.1 to 500 μm is preferred.

[0234] [Laminate] 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 of this embodiment, 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). The semi-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 a dry state, i.e., to the extent that it is not 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 of the semi-cured state (Stage B) is usually 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 (TA Instruments ARES-G2 (product name)). 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%.

[0235] [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. The metal foil-clad laminate may also include at least one prepreg of this embodiment and metal foil laminated on one or both sides of the prepreg. Furthermore, the metal foil-clad laminate may include at least one resin sheet of this embodiment and metal foil laminated on one or both sides of the resin sheet.

[0236] In the metal foil-clad laminate of this embodiment, the resin compositions used in each prepreg and resin sheet may be the same or different, and when both prepregs and resin sheets are used, the resin compositions used in them may be the same or different. In the metal foil-clad laminate of this embodiment, 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.

[0237] In the metal foil-clad laminate of this embodiment, one or more metal foils selected from the group consisting of the prepreg and the resin sheet of this embodiment 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 prepreg and the resin sheet of this embodiment. "Laminated so as to be in contact with the surface of one or more of the prepreg and the resin sheet of this embodiment" 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 be increased, and the insulation reliability of the printed circuit board tends to be improved.

[0238] The metal foil-clad laminate of this embodiment may have one or more stacked prepreg and / or resin sheets according to this embodiment, and metal foil arranged on one or both sides of the prepreg and / or resin sheets. A method for manufacturing the metal foil-clad laminate of this embodiment is, for example, a method of stacking one or more prepreg and / or resin sheets according to this embodiment and arranging metal foil on one or both sides thereof to form a laminate. The molding method is a method that is normally used when molding laminates and multilayer boards for printed circuit boards, and more specifically, a multi-stage press, multi-stage vacuum press, continuous molding machine, autoclave molding machine, etc., with a temperature of about 180 to 350°C, a heating time of about 100 to 300 minutes, and a surface pressure of 20 to 100 kgf / cm². 2 One method is lamination molding to a certain extent.

[0239] Furthermore, a multilayer board can be produced by laminating the prepreg and / or resin sheet of this embodiment with a separately manufactured wiring board for the inner layer. As a method for manufacturing the multilayer board, for example, copper foil with a thickness of about 35 μm is placed on both sides of one or more stacked prepreg and / or resin sheets of this embodiment, and the layers are laminated using the molding method described above to form a copper foil-clad laminate. Then, an inner layer circuit is formed, and this circuit is subjected to a blackening treatment to form an inner layer circuit board. After this, the inner layer circuit board and the prepreg and / or resin sheet of this embodiment are alternately placed one by one, and copper foil is placed as the outermost layer. A multilayer board can be produced by laminating the layers under the above conditions, preferably under vacuum. The metal foil-clad laminate of this embodiment can be suitably used as a printed wiring board.

[0240] (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 to 70 μm.

[0241] [Printed Wiring Board] The printed wiring 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 of this embodiment (a layer containing a cured product) and a layer formed from a prepreg (a layer containing a cured product). Such a printed wiring 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 wiring board is shown below.

[0242] First, the metal foil-clad laminate described above is prepared. Next, the surface of the metal foil-clad laminate is etched to form the inner layer circuit, thereby creating an inner layer substrate. The inner layer circuit surface of this inner layer substrate is then treated to increase adhesive strength as needed, and the required number of prepregs described above are stacked on the inner layer circuit surface. Then, metal foil for the outer layer circuit is laminated on the outside of that, and the substrate is heated and pressed to form an integral structure. In this way, a multilayer laminate is manufactured in which an insulating layer made of the substrate and a cured resin composition of this embodiment is formed between the inner layer circuit and the copper foil for the outer layer circuit. Next, holes for through-holes and via holes are drilled in this multilayer laminate, and a plated metal film is formed on the walls of these holes to allow conductivity between the inner layer circuit and the metal foil for the outer layer circuit. Then, the metal foil for the outer layer circuit is etched to form the outer layer circuit, thereby manufacturing a printed circuit board.

[0243] 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 product of the resin composition according to this embodiment. That is, the prepreg according to this embodiment (including a base material and a cured product of the resin composition of this embodiment impregnated or coated therein), the layer of the resin composition of the metal foil laminate of this embodiment (a layer containing a cured product of the resin composition of this embodiment) are composed of an insulating layer containing a cured product of the resin composition of this embodiment.

[0244] [Semiconductor Device] A semiconductor device can be manufactured by mounting semiconductor chips on conductive locations on the printed circuit board of this embodiment. Here, conductive locations are locations on the multilayer printed circuit board that transmit electrical signals, and these locations may 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.

[0245] A method for mounting a semiconductor chip in manufacturing a semiconductor device is not particularly limited as long as the semiconductor chip functions effectively. Specific examples thereof include a wire bonding mounting method, a flip-chip mounting method, a bump-less build-up layer (BBUL) mounting method, a mounting method using an anisotropic conductive film (ACF), and a mounting method using a non-conductive film (NCF).

[0246] Hereinafter, the present embodiment will be described more specifically with reference to Examples and Comparative Examples. The present embodiment is not limited in any way by the following examples.

[0247] [Method for measuring relative dielectric constant (Dk) and dielectric loss tangent (Df)] Using rutile-type titanium oxide containing molybdenum (molybdenum-doped titanium oxide), surface-coated titanium oxide, strontium titanate, or barium titanate as dielectric powder, the relative dielectric constant (Dk) and dielectric loss tangent (Df) of each were measured by the cavity resonator method in the following manner. First, a PTFE (polytetrafluoroethylene) tube (inner diameter: 1.5 mm, manufactured by NICHIAS Corporation) was filled with 200 mg of the dielectric powder to obtain a measurement sample (S). For this measurement sample (S), the relative dielectric constant (Dk) and dielectric loss tangent (Df) at 10 GHz were measured using a network analyzer (Agilent 8722ES (trade name), manufactured by Agilent Technologies, Inc.). The measurements of relative dielectric constant (Dk) and dielectric loss tangent (Df) were performed in an environment with a temperature of 23°C±1°C and a humidity of 50% RH (relative humidity)±5% RH.

[0248] Similarly, the PTFE (polytetrafluoroethylene) tube (inner diameter: 1.5 mm, manufactured by NICHIAS Corporation) itself was used as a sample (B), which served as a blank, and the relative dielectric constant (Dk) and dielectric loss tangent (Df) at 10 GHz of this sample (B) were measured. From these measurement results, the relative dielectric constant (Dk) and dielectric loss tangent (Df) of the dielectric powder at 10 GHz were respectively calculated using the following Bruggeman's formula (ii). Formula (ii): f ａ ×[(ε ａ −ε ｄ ) / (ε ａ +2ε ｄ )]+fｂ × [(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 f is the volume fraction (vol%) of air in the sample being measured. 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.

[0249] 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.

[0250] Next, in the measurement sample (S) (containing PTFE, air, and dielectric powder), the volume fraction f of the dielectric powder was measured. ｃＳ The volume fraction (vol%) was calculated using the inner diameter and length of the PTFE tube, the mass difference before and after dielectric powder filling, and the specific gravity of the dielectric powder. ａＳ Assuming it is 54 (vol%), the calculated volume fraction fｃＳ Using this, the volume fraction f of air ｂＳ (vol%) was calculated. Then, in the same manner as with sample (B), the complex dielectric constant ε of sample (S) (containing PTFE, air, and dielectric powder) was calculated from the measurement results (Dk and Df) of the measurement sample (S). ｄＳ The complex permittivity of air, ε, was calculated. ｂ Assuming ε = 1.0, the ε calculated using sample (B) ａ and, f ａＳ , f ｂＳ , f ｃＳ , and ε ｄＳ Using equation (ii), the complex dielectric constant ε of the dielectric powder is obtained. ｃ The calculated ε was obtained. ｃ From this, the Dk and Df of the dielectric powder were calculated.

[0251] [Method for measuring average particle size] Molybdenum-doped titanium oxide, surface-coated titanium oxide, strontium titanate, or barium titanate were used as dielectric powders, and the average particle size (D50) of each dielectric powder was measured as follows. Specifically, the average particle size (D50) was calculated by measuring the particle size distribution using the laser diffraction / scattering method based on the following measurement conditions, using a laser diffraction / scattering particle size distribution analyzer (Microtrac MT3300EXII (product name) manufactured by Microtrac Bell Co., Ltd.).

[0252] (Measurement conditions for laser diffraction / scattering particle size distribution analyzer) ・Molybdenum-doped titanium oxide: Solvent: methyl ethyl ketone, Solvent refractive index: 1.33, Particle refractive index: 2.72, Transmittance: 85±5%. ・Surface-coated titanium oxide: Solvent: methyl ethyl ketone, Solvent refractive index: 1.33, Particle refractive index: 2.72, Transmittance: 85±5%. ・Strontium titanate: Solvent: methyl ethyl ketone, Solvent refractive index: 1.33, Particle refractive index: 2.41, Transmittance: 85±5%. ・Barium titanate: Solvent: methyl ethyl ketone, Solvent refractive index: 1.33, Particle refractive index: 2.41, Transmittance: 85±5%.

[0253] [Compositional analysis of molybdenum-doped titanium oxide by X-ray fluorescence] Approximately 100 mg of the sample was placed on filter paper, covered with a polypropene film, and the composition of molybdenum-doped titanium oxide was analyzed using X-ray fluorescence (ZSX100e / Rigaku Denki Kogyo Co., Ltd.).

[0254] [Synthesis Example 1] Synthesis of naphthol aralkyl type cyanate ester compound (SN495V-CN) 300 g of naphthol aralkyl type phenol resin (SN495V (trade name), OH group (hydroxyl group) equivalent: 236 g / eq., manufactured by 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 1 mol of hydroxyl group) were dissolved in 1800 g of dichloromethane to make Solution 1. Solution 1 was added over 30 minutes while stirring, maintaining the liquid temperature at -2 to -0.5°C, by adding 125.9 g (2.05 mol) of cyanogen chloride (1.6 mol per mol of hydroxyl groups), 293.8 g of dichloromethane, 194.5 g (1.92 mol) of 36% hydrochloric acid (1.5 mol per mol of hydroxyl groups), and 1205.9 g of water. After adding Solution 1, the mixture was stirred at the same temperature for 30 minutes, and then Solution 2, a solution of 65 g (0.64 mol) of triethylamine (0.5 mol per 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 phase from the aqueous phase, and the resulting organic phase was washed five times with 1300 g of water. The electrical conductivity of the wastewater after the fifth rinse 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 was concentrated under reduced pressure and finally concentrated to dryness at 90°C for 1 hour to obtain 331 g of the target naphthol aralkyl type cyanate ester compound (SN495V-CN, equivalent weight of cyanate group: 261 g / eq., where all R6 atoms in formula (1) above are hydrogen atoms and n2 is an integer from 1 to 10) (orange viscous substance). The infrared absorption spectrum of the obtained SN495V-CN was 2250 cm⁻¹. -1 Absorption of the cyanate group was observed, but absorption of the hydroxyl group was not.

[0255] [Preparation Example 1] Synthesis of Molybdenum-Doped Titanium Oxide 0.4 g of anatase-type titanium oxide (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.1 g of molybdenum trioxide (manufactured by Wako Pure Chemical Industries, Ltd.) were mixed in a mortar to obtain a mixture of anatase-type titanium oxide and molybdenum oxide of 0.5 g. The obtained mixture was placed in a crucible and fired at 1100°C for 3 hours in a ceramic electric furnace (AMF-2P type ceramic electric furnace ARF-100K type firing furnace equipment, manufactured by Asahi Rika Seisakusho Co., Ltd.). After cooling, the crucible was removed and 0.28 g of light gray powder was obtained. Quantitative analysis of the obtained powder using X-ray fluorescence confirmed that the obtained particles contained 98.4% titanium oxide and 0.9% molybdenum. From these results, it was confirmed that the obtained powder was molybdenum-doped titanium oxide.

[0256] [Example 1] 53 parts by mass of the naphthol aralkyl type cyanate ester compound obtained in Synthesis Example 1 (SN495V-CN, equivalent amount of cyanate group: 261 g / eq.), naphthalene type epoxy resin (EPICLON®) A resin varnish was obtained by mixing 47 parts by mass of EXA-4032-70M (trade name), epoxy equivalent: 150 g / eq., manufactured by DIC Corporation, 250 parts by mass of molybdenum-doped titanium oxide obtained in Preparation Example 1 (average particle size (D50): 1.10 μm, relative permittivity (Dk): 35, dielectric loss tangent (Df): 0.001), 2 parts by mass of silane coupling agent (KBM-1403 (trade name), manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by mass of wetting and dispersing agent (BYK®-W903 (trade name), manufactured by BIC Chemie Japan Co., Ltd.), 0.1 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.01 parts by mass of manganese octoate (Nikka Octix Manganese (trade name), manufactured by Nippon Chemical Industrial Co., Ltd.), and 120 parts by mass of methyl ethyl ketone. The functional group equivalent ratio of cyanate ester compound (B) to epoxy compound (C) in the resin varnish was 0.6.

[0257] [Example 2] A resin varnish was obtained in the same manner as in Example 1, except that 47 parts by mass of biphenyl aralkyl type epoxy resin (NC-3000FH (trade name), epoxy equivalent: 328 g / eq., manufactured by Nippon Kayaku Co., Ltd.) was used instead of 47 parts by mass of naphthalene type epoxy resin (EPICLON® EXA-4032-70M (trade name), manufactured by DIC Corporation). The functional group equivalent ratio of cyanate ester compound (B) to epoxy compound (C) in the resin varnish was 1.4.

[0258] [Example 3] A resin varnish was obtained in the same manner as in Example 1, except that 20 parts by mass were used instead of 53 parts by mass of the naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, and 80 parts by mass of biphenyl aralkyl type epoxy resin (NC-3000FH (trade name), manufactured by Nippon Kayaku Co., Ltd.) were used instead of 47 parts by mass of naphthalene type epoxy resin (EPICLON® EXA-4032-70M (trade name), manufactured by DIC Corporation). The functional group equivalent ratio of the cyanate ester compound (B) to the epoxy compound (C) in the resin varnish was 0.3.

[0259] [Example 4] 53 parts by mass of naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, naphthalene type epoxy resin (EPICLON®) 5 parts by mass of EXA-4032-70M (trade name), epoxy equivalent: 150 g / eq., manufactured by DIC Corporation; 42 parts by mass of biphenyl aralkyl type epoxy resin (NC-3000FH (trade name), epoxy equivalent: 328 g / eq., manufactured by Nippon Kayaku Co., Ltd.); 250 parts by mass of molybdenum-doped titanium oxide obtained in Preparation Example 1; 2 parts by mass of silane coupling agent (KBM-1403 (trade name), manufactured by Shin-Etsu Chemical Co., Ltd.); 2 parts by mass of wetting and dispersing agent (BYK®-W903 (trade name), manufactured by BIC Chemie Japan Co., Ltd.); 0.1 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.); 0.01 parts by mass of manganese octoate (Nikka Octix Manganese (trade name), manufactured by Nippon Chemical Industrial Co., Ltd.); and 120 parts by mass of methyl ethyl ketone were mixed to obtain a resin varnish. Furthermore, the functional group equivalent ratio of the cyanate ester compound (B) to the epoxy compound (C) in the resin varnish was 1.3.

[0260] [Example 5] A resin varnish was obtained in the same manner as in Example 1, except that 47 parts by mass of naphthylene ether type epoxy resin (NC-6000 (trade name), epoxy equivalent: 250 g / eq., manufactured by DIC Corporation) was used instead of 47 parts by mass of naphthalene type epoxy resin (EPICLON® EXA-4032-70M (trade name), manufactured by DIC Corporation). The functional group equivalent ratio of cyanate ester compound (B) to epoxy compound (C) in the resin varnish was 1.1.

[0261] [Example 6] 53 parts by mass of naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, naphthalene type epoxy resin (EPICLON®) 44 parts by mass of EXA-4032-70M (trade name), epoxy equivalent: 150 g / eq., manufactured by DIC Corporation, 3 parts by mass of butadiene skeleton-containing epoxy resin (R-45EPT (trade name), epoxy equivalent: 1570 g / eq., manufactured by Nagase ChemteX Corporation), 250 parts by mass of molybdenum-doped titanium oxide obtained in Preparation Example 1, 2 parts by mass of silane coupling agent (KBM-1403 (trade name), manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by mass of wetting and dispersing agent (BYK®-W903 (trade name), manufactured by BIC Chemie Japan Co., Ltd.), 0.1 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.01 parts by mass of manganese octoate (Nikka Octix Manganese (trade name), manufactured by Nippon Chemical Industrial Co., Ltd.), and 120 parts by mass of methyl ethyl ketone were mixed to obtain a resin varnish. The functional group equivalent ratio of the cyanate ester compound (B) to the epoxy compound (C) in the resin varnish was 0.7.

[0262] [Example 7] A resin varnish was obtained in the same manner as in Example 1, except that 12 parts by mass of a bisphenol A type cyanate compound (Primaset® BADCy (trade name), equivalent of cyanate group: 139 g / eq., manufactured by Lonza) was used instead of 53 parts by mass of the naphthol aralkyl type cyanate ester compound (SN495V-CN, equivalent of cyanate group: 261 g / eq.) obtained in Synthesis Example 1, and 88 parts by mass of a biphenyl aralkyl type epoxy resin (NC-3000FH (trade name), manufactured by Nippon Kayaku Co., Ltd.) was used instead of 47 parts by mass of a naphthalene type epoxy resin (EPICLON® EXA-4032-70M (trade name), epoxy equivalent: 150 g / eq., manufactured by DIC Corporation). The functional group equivalent ratio of the cyanate ester compound (B) to the epoxy compound (C) in the resin varnish was 0.3.

[0263] [Example 8] A resin varnish was obtained in the same manner as in Example 2, except that 150 parts by mass were used instead of 250 parts by mass of molybdenum-doped titanium oxide obtained in Preparation Example 1. The functional group equivalent ratio of cyanate ester compound (B) to epoxy compound (C) in the resin varnish was 1.4.

[0264] [Comparative Example 1] 91 parts by mass of naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, naphthalene type epoxy resin (EPICLON®) A resin varnish was obtained by mixing 9 parts by mass of EXA-4032-70M (trade name), epoxy equivalent: 150 g / eq., manufactured by DIC Corporation, 250 parts by mass of molybdenum-doped titanium oxide obtained in Preparation Example 1, 2 parts by mass of silane coupling agent (KBM-1403 (trade name), manufactured by Shin-Etsu Chemical Co., Ltd.), 2 parts by mass of wetting and dispersing agent (BYK®-W903 (trade name), manufactured by BIC Chemie Japan Co., Ltd.), 0.1 parts by mass of 2,4,5-triphenylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.01 parts by mass of manganese octoate (Nikka Octix Manganese (trade name), manufactured by Nippon Chemical Industrial Co., Ltd.), and 120 parts by mass of methyl ethyl ketone. The functional group equivalent ratio of cyanate ester compound (B) to epoxy compound (C) in the resin varnish was 5.8.

[0265] [Comparative Example 2] A resin varnish was obtained in the same manner as in Example 1, except that 9 parts by mass were used instead of 91 parts by mass of the naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, and 91 parts by mass were used instead of 9 parts by mass of naphthalene type epoxy resin (EPICLON® EXA-4032-70M (trade name), manufactured by DIC Corporation). The functional group equivalent ratio of the cyanate ester compound (B) to the epoxy compound (C) in the resin varnish was 0.057.

[0266] [Comparative Example 3] A resin varnish was obtained in the same manner as in Example 1, except that 74 parts by mass were used instead of 91 parts by mass of the naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, and 26 parts by mass of biphenyl aralkyl type epoxy resin (NC-3000FH (trade name), manufactured by Nippon Kayaku Co., Ltd.) were used instead of 9 parts by mass of naphthalene type epoxy resin (EPICLON® EXA-4032-70M (trade name), manufactured by DIC Corporation). The functional group equivalent ratio of the cyanate ester compound (B) to the epoxy compound (C) in the resin varnish was 3.6.

[0267] [Comparative Example 4] A resin varnish was obtained in the same manner as in Example 1, except that 80 parts by mass were used instead of 91 parts by mass of the naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, and 20 parts by mass of biphenyl aralkyl type epoxy resin (NC-3000FH (trade name), manufactured by Nippon Kayaku Co., Ltd.) were used instead of 9 parts by mass of naphthalene type epoxy resin (EPICLON® EXA-4032-70M (trade name), manufactured by DIC Corporation). The functional group equivalent ratio of the cyanate ester compound (B) to the epoxy compound (C) in the resin varnish was 5.0.

[0268] [Comparative Example 5] A resin varnish was obtained in the same manner as in Example 1, except that 5 parts by mass were used instead of 91 parts by mass of the naphthol aralkyl type cyanate ester compound (SN495V-CN) obtained in Synthesis Example 1, and 95 parts by mass of biphenyl aralkyl type epoxy resin (NC-3000FH (trade name), manufactured by Nippon Kayaku Co., Ltd.) were used instead of 9 parts by mass of naphthalene type epoxy resin (EPICLON® EXA-4032-70M (trade name), manufactured by DIC Corporation). The functional group equivalent ratio of the cyanate ester compound (B) to the epoxy compound (C) in the resin varnish was 0.066.

[0269] [Comparative Example 6] A resin varnish was obtained in the same manner as in Example 2, except that 250 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, CR-63 (trade name), Ishihara Sangyo Co., Ltd.) was used instead of 250 parts by mass of molybdenum-doped titanium oxide obtained in Preparation Example 1. The functional group equivalent ratio of cyanate ester compound (B) to epoxy compound (C) in the resin varnish was 1.4.

[0270] [Comparative Example 7] Instead of 250 parts by mass of molybdenum-doped titanium oxide obtained in Preparation Example 1, strontium titanate (SrTiO) ３ A resin varnish was obtained in the same manner as in Example 2, except that 300 parts by mass of a perovskite oxide (ST-2, trade name, manufactured by Kyoritsu Material Co., Ltd.) was used, with the exception of using a perovskite oxide with an average particle size (D50): 0.3 μm, relative permittivity (Dk): 21, dielectric loss tangent (Df): 0.007. In order to make the volume fraction of dielectric powder in the resin varnish the same as in Example 1, which used molybdenum-doped titanium oxide obtained in Preparation Example 1, the amount of strontium titanate used was 300 parts by mass. The functional group equivalent ratio of cyanate ester compound (B) to epoxy compound (C) in the resin varnish was 1.4.

[0271] [Comparative Example 8] Instead of 250 parts by mass of molybdenum-doped titanium oxide obtained in Preparation Example 1, barium titanate (BaTi) ４ O ９ A resin varnish was obtained in the same manner as in Example 2, except that 265 parts by mass of a compound having the structure represented by (BT-149, trade name, manufactured by Nippon Chemical Industrial Co., Ltd.) was used, with an average particle size (D50): 2.10 μm, relative permittivity (Dk): 19, dielectric loss tangent (Df): 0.003. In order to make the volume fraction of dielectric powder in the resin varnish the same as in Example 1, which used molybdenum-doped titanium oxide obtained in Preparation Example 1, the amount of barium titanate used was 265 parts by mass. The functional group equivalent ratio of the cyanate ester compound (B) and the epoxy compound (C) in the resin varnish was 1.4.

[0272] [Prepregs and Metal Foil-Clad Laminates] Prepregs and metal foil-clad laminates were prepared using the resin varnishes obtained in Examples 1 to 8 and Comparative Examples 1 to 8, respectively. Specifically, the resin varnish was impregnated onto 0.094 mm thick E glass cloth (1031NT S640 (trade name), manufactured by Arisawa Seisakusho Co., Ltd.), and heated and dried at 130°C for 3 minutes to obtain a 0.1 mm thick prepreg. Next, four of the obtained prepregs were stacked, and 12 μm thick electrolytic copper foil (3EC-M3-VLP (trade 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 0.4 mm thick metal foil-clad laminate (double-sided copper-clad laminate) was fabricated by lamination molding using a vacuum press at 220°C for 120 minutes. The physical properties of the obtained prepreg and metal foil-clad laminate were measured according to the following evaluation method, and the measurement results are shown in Tables 1 and 2.

[0273] [Evaluation Method] (1) Two prepregs obtained in the copper foil peel strength examples and comparative examples were laminated, and electrolytic copper foil with a thickness of 12 μm (3EC-M3-VLP (product name), manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the upper and lower surfaces, with a surface pressure of 30 kgf / cm². ２ A 0.2 mm thick metal foil-clad laminate (double-sided copper-clad laminate) was fabricated by lamination molding using a vacuum press at 220°C for 120 minutes. Using this metal foil-clad laminate (10 mm × 100 mm × 0.2 mm), the copper foil peel strength (copper foil adhesion, kgf / cm) was measured in accordance with JIS C6481.

[0274] (2) Relative permittivity (Dk) and dielectric loss tangent (Df) The copper foil on both sides of the metal foil-clad laminates obtained in the examples and comparative examples was completely etched to obtain an unclad plate with a thickness of 0.1 mm from which all the copper foil on both sides had been removed. This unclad plate was cut (downsized) to a size of 1 mm × 65 mm to obtain a sample for measurement. Using this sample for measurement, the relative permittivity (Dk) and dielectric loss tangent (Df) at 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) were measured under conditions of a temperature of 23°C ± 1°C and a humidity of 50% RH (relative humidity) ± 5% RH.

[0275] (3) Heat resistance of copper-coated solder (heat resistance) Two prepregs obtained in the examples and comparative examples were laminated, and electrolytic copper foil with a thickness of 12 μm (3EC-M3-VLP (product name), manufactured by Mitsui Mining & Smelting Co., Ltd.) was placed on the upper and lower surfaces, with a surface pressure of 30 kgf / cm ２ A 0.2 mm thick metal foil-clad laminate (double-sided copper-clad laminate) was fabricated by lamination molding using a vacuum press at 220°C for 120 minutes. This metal foil-clad laminate was cut (downsized) to a size of 50 mm x 50 mm to obtain measurement samples. Three measurement samples were prepared in the same manner. Each measurement sample was floated in a 260°C solder bath for 30 minutes so that only one side of the sample was in contact with the solder. After 30 minutes, the samples were removed from the solder bath, and the presence or absence of changes in the appearance of the side in contact with the solder was visually observed. Based on the results of observing each of the three samples, a "○" was evaluated if there were no appearance abnormalities in any of the samples, and a "×" was evaluated if there was an appearance abnormality in one or more samples. In the sample, for example, if blistering was observed at the interface between the metal foil and the insulating layer, it was judged to be an appearance abnormality.

[0276]

[0277]

[0278] [Resin Sheet] A resin sheet was prepared by applying the resin varnish obtained in Example 1 to a polyethylene terephthalate film as a support and heating and drying it at 130°C for 5 minutes. The obtained resin sheet was visually confirmed to have a good appearance.

[0279] This application is based on Japanese Patent Application No. 2025-053706 filed on March 27, 2025, the contents of which are incorporated herein by reference.

[0280] The resin composition of this embodiment can be suitably used 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, fiber-reinforced composite materials, or in the manufacture of semiconductor devices.

Claims

It contains titanium oxide (A) containing molybdenum, a cyanate ester compound (B), and an epoxy compound (C), The functional group equivalent ratio (cyanato group / epoxy group) between the cyanate group of the cyanate ester compound (B) and the epoxy group of the epoxy compound (C) is 0.1 to 2.

0. Resin composition. 　 The resin composition according to claim 1, wherein the average particle size of the titanium oxide (A) is 0.1 to 100 μm. 　 The resin composition according to claim 1, wherein the titanium oxide (A) containing molybdenum is molybdenum-doped titanium oxide. 　 The resin composition according to claim 1, wherein the content of titanium oxide (A) is 50 to 500 parts by mass per 100 parts by mass of the total resin solids in the resin composition. 　 The resin composition according to claim 1, wherein the cyanate ester compound (B) 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, and biphenyl aralkyl type cyanate ester compounds. 　 The resin composition according to claim 1, wherein the epoxy compound (C) 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. 　 The resin composition according to claim 1, further comprising one or more thermosetting resins or compounds selected from the group consisting of maleimide compounds, modified polyphenylene ether compounds, phenol compounds, alkenyl-substituted nadiimide compounds, oxetane resins, benzoxazine compounds, and compounds having polymerizable unsaturated groups. 　 The resin composition according to claim 1, further comprising a filler different from titanium oxide (A). 　 The resin composition according to claim 8, wherein the filler comprises one or more selected from the group consisting of silica, alumina, talc, aluminum nitride, boron nitride, boehmite, aluminum hydroxide, zinc molybdate, silicone rubber powder, and silicone composite powder. 　 The resin composition according to claim 8, wherein the content of the filler is 50 to 300 parts by mass with respect to 100 parts by mass of the total resin solids in the resin composition. 　 The resin composition according to claim 1, for use in printed circuit boards. 　 Substrate and A prepreg comprising a resin composition according to any one of claims 1 to 11, which is impregnated or coated onto the substrate. 　 A resin sheet comprising the resin composition according to any one of claims 1 to 11. 　 A laminate comprising the prepreg described in claim 12. 　 A laminate comprising the resin sheet described in claim 13. 　 The laminate according to claim 14, A metal foil-clad laminate, comprising a metal foil arranged on one or both sides of the laminate. 　 The laminate according to claim 15, A metal foil-clad laminate, comprising a metal foil arranged on one or both sides of the laminate. 　 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 according to any one of claims 1 to 11.

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