Resin composition, prepreg, resin-equipped film, resin-equipped metal foil, metal-clad laminate, and wiring board

Abstract

An aspect of the present invention relates to a resin composition which comprises a radical polymerizable compound (A) and a boron nitride filler (B), wherein: the radical polymerizable compound (A) contains an N-phenylmaleimide compound (A-1) that does not contain an alkyl group having 2 or more carbon atoms; the boron nitride filler (B) includes a scale-like boron nitride filler (B-1); and in a cured product of the resin compound, a change rate (ΔDf) defined by the following formula (1) is not more than 50%. (In formula (1), Df1 is the relative permittivity of the cured product at 10 GHz before heat treatment, and Df2 is the relative permittivity of the cured product at 10 GHz after heat treatment at 188°C for 500 hours.)

Description

Resin composition, prepreg, resin-coated film, resin-coated metal foil, metal-clad laminate, and wiring board

[0001] The present invention relates to a resin composition, a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board.

[0002] As the amount of information processed in various electronic devices increases, packaging technologies such as higher integration of semiconductor devices, higher density wiring, and multi-layering are advancing. Furthermore, wiring boards used in various electronic devices are required to have characteristics suited to their specific applications. For example, millimeter-wave radar boards for automotive applications require wiring boards that are compatible with high frequencies. Furthermore, there is a need to reduce loss during signal transmission, which is particularly important for wiring boards that are compatible with high frequencies. To meet these requirements, the substrate material that constitutes the insulating layer of the wiring board must have a low dielectric constant and dielectric loss tangent.

[0003] As such a substrate material, for example, a PPE-containing resin composition containing PPE (polyphenylene ether), a crosslinkable curable compound, a phosphaphenanthrene derivative, and silica has been reported (Patent Document 1).

[0004] On the other hand, electronic materials used in PA (power amplifier) ​​substrates for base stations and the like are required to have not only low dielectric constants and dielectric loss tangents but also high thermal conductivity. In this regard, the inorganic filler (silica) contained in the resin composition of Patent Document 1 may not be able to provide sufficient thermal conductivity.

[0005] As a technique for improving thermal conductivity, a resin composition containing boron nitride, which is known as an inorganic filler with high thermal conductivity, a bismaleimide compound, and a curing agent for the same has been reported (Patent Document 2).

[0006] Recently, there has been a demand for substrate materials that combine low dielectric properties with high thermal conductivity, and there is also a growing need for materials that can maintain low dielectric properties even in harsher environments (high temperatures). In this regard, the technology described in Patent Document 2 aims to achieve both heat resistance and high thermal conductivity, but has not been verified to maintain low dielectric properties at high temperatures.

[0007] JP 2015-67700 A JP 2023-24739 A

[0008] The present invention has been made in view of the above circumstances, and aims to provide a resin composition that can give a cured product having low dielectric properties and high thermal conductivity, and that is resistant to deterioration of the low dielectric properties even at high temperatures. Another aim of the present invention is to provide a prepreg, a resin-coated film, a resin-coated metal foil, a metal-clad laminate, and a wiring board that can be obtained using the resin composition.

[0009] As a result of extensive investigations, the present inventors have found that the above object can be achieved by the following constitution, and have achieved the present invention through further investigations.

[0010] That is, a resin composition according to one embodiment of the present invention is a resin composition comprising a radically polymerizable compound (A) and a boron nitride filler (B), wherein the radically polymerizable compound (A) comprises an N-phenylmaleimide compound (A-1) that does not contain an alkyl group having two or more carbon atoms, and the boron nitride filler (B) comprises a scaly boron nitride filler (B-1), and wherein a cured product of the resin composition has a rate of change in dielectric loss tangent (ΔDf) defined by the following formula (1) of 50% or less:

[0011]

[0012] (In formula (1), Df １ is the dielectric loss tangent of the cured product before heat treatment at 10 GHz, and Df ２ is the dielectric loss tangent at 10 GHz of the cured product after heat treatment at 188°C for 500 hours.

[0013] Fig. 1 is a schematic cross-sectional view showing an example of a prepreg according to an embodiment of the present invention. Fig. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate according to an embodiment of the present invention. Fig. 3 is a schematic cross-sectional view showing an example of a wiring board according to an embodiment of the present invention. Fig. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil according to an embodiment of the present invention. Fig. 5 is a schematic cross-sectional view showing an example of a resin-coated film according to an embodiment of the present invention.

[0014] Hereinafter, embodiments of the present invention will be specifically described, but the present invention is not limited to these.

[0015] [Resin Composition] A resin composition according to an embodiment of the present invention contains a radically polymerizable compound (A) and a boron nitride filler (B). The radically polymerizable compound (A) contains an N-phenylmaleimide compound (A-1) that does not contain an alkyl group having two or more carbon atoms. The boron nitride filler (B) contains a scaly boron nitride filler (B-1). Furthermore, the resin composition according to this embodiment, in a cured product thereof, has a rate of change in dielectric loss tangent (ΔDf) defined by the following formula (1) of 50% or less.

[0016]

[0017] However, in the above formula (1), Df １ is the dielectric loss tangent of the cured product before heat treatment, and Df ２ is the dielectric loss tangent of the cured product after heat treatment at 188° C. for 500 hours. In this embodiment, the term "dielectric loss tangent" refers to the dielectric loss tangent at a frequency of 10 GHz.

[0018] The above-described configuration makes it possible to obtain a cured product having low dielectric properties (particularly "dielectric loss tangent (Df)") and high thermal conductivity, and further to provide a resin composition in which the low dielectric properties are resistant to deterioration even at elevated induction temperatures.

[0019] That is, the resin composition of the present embodiment has the advantage that the cured product thereof can have both high thermal conductivity and low dielectric properties, and further, the low dielectric properties are not easily deteriorated even at high temperatures, and therefore is extremely useful industrially.

[0020] The resin composition of the present embodiment preferably has a dielectric loss tangent (Df) of 0.0045 or less in a cured product before the heat treatment (at 188°C for 500 hours). The cured product preferably has a thermal conductivity of 0.7 W / m K or more.

[0021] First, each component of the resin composition of the present embodiment will be described.

[0022] (Radical Polymerizable Compound (A)) The radical polymerizable compound (A) of the present embodiment is a compound having radical polymerizability, and contains at least an N-phenylmaleimide compound (A-1) that does not contain an alkyl group having two or more carbon atoms.

[0023] N-Phenylmaleimide Compound (A-1) The N-phenylmaleimide compound (A-1) of this embodiment is a compound having an N-phenylmaleimide group in the molecule and not containing an alkyl group having two or more carbon atoms in the molecule. Two or more N-phenylmaleimide groups may be contained in the molecule.

[0024] Such a maleimide compound (A-1) has high chemical thermal stability, and therefore, by including the maleimide compound (A-1), the resin composition of the present embodiment has excellent heat resistance in the cured product thereof. Heat resistance here means that the low dielectric properties are not easily deteriorated by high temperatures.

[0025] Specific examples of the maleimide compound (A-1) used in this embodiment include 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, and 4-methyl-1,3-phenylene bismaleimide. The maleimide compound (A-1) used in this embodiment may be a commercially available product, and it is preferable to use, for example, MIR-3000-70MT, MIR-5000-50T, or the like manufactured by Nippon Kayaku Co., Ltd.

[0026] Radically Polymerizable Compound (A-2) The radically polymerizable compound (A) of the present embodiment may contain a radically polymerizable compound (A-2) other than the maleimide compound (A-1) described above. Specific examples of the radically polymerizable compound (A-2) include a radically polymerizable compound different from the maleimide compound (A-1), such as a polyphenylene ether compound having a carbon-carbon unsaturated double bond in the molecule, a hydrocarbon compound having a carbon-carbon unsaturated double bond in the molecule, a maleimide compound other than the above, and an allyl compound.

[0027] The molecular weight of the radical polymerizable compound (A-2) is preferably a weight-average molecular weight of about 100 to 3000. The weight-average molecular weight may be measured by a general molecular weight measurement method, and specific examples thereof include values ​​measured using gel permeation chromatography (GPC).

[0028] The radical polymerizable compound (A-2) will be specifically described below.

[0029] Polyphenylene ether compounds Examples of polyphenylene ether compounds having a carbon-carbon unsaturated double bond in the molecule include polyphenylene ether compounds having a group represented by the following formula (1) or formula (2). It is believed that the inclusion of such a modified polyphenylene ether compound results in a resin composition that can give a cured product with low dielectric properties and high heat resistance.

[0030]

[0031] In formula (1), s represents an integer of 0 to 10. Z represents an arylene group. １ ~R ３ are independent of each other. That is, R １ ~R ３ may be the same group or different groups. １ ~R ３ represents a hydrogen atom or an alkyl group.

[0032] In addition, in formula (1), when s is 0, this indicates that Z is directly bonded to the end of the polyphenylene ether.

[0033] The arylene group represented by Z is not particularly limited. Examples of the arylene group include monocyclic aromatic groups such as a phenylene group, and polycyclic aromatic groups in which the aromatic ring is not monocyclic but is a polycyclic aromatic ring such as a naphthalene ring. The arylene group also includes derivatives in which a hydrogen atom bonded to the aromatic ring is substituted with a functional group such as an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. The alkyl group is not particularly limited, and is preferably an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0034]

[0035] In formula (2), R ４ represents a hydrogen atom or an alkyl group. The alkyl group is not particularly limited, and is preferably, for example, an alkyl group having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0036] Preferred specific examples of the substituent represented by formula (1) include, for example, a substituent containing a vinylbenzyl group. Examples of the substituent containing a vinylbenzyl group include, for example, a substituent represented by formula (3) below. Furthermore, examples of the substituent represented by formula (2) include an acrylate group and a methacrylate group.

[0037]

[0038] More specific examples of the substituent include vinylbenzyl groups (ethenylbenzyl groups) such as p-ethenylbenzyl and m-ethenylbenzyl groups, vinylphenyl groups, acrylate groups, and methacrylate groups.

[0039] In the resin composition of the present embodiment, it is more preferable that the polyphenylene ether compound has a group represented by the above formula (2), because this has the advantage of improving the reactivity with the crosslinking agent and making it easier to obtain a cured resin product with high heat resistance.

[0040] The polyphenylene ether compound has a polyphenylene ether chain in the molecule, and preferably has, for example, a repeating unit represented by the following formula (4) in the molecule.

[0041]

[0042] In formula (4), t represents 1 to 50. ５ ~R ８ are independent of each other. That is, R ５ ~R ８ may be the same group or different groups. ５ ~R ８ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0043] R ５ ~R ８ Specific examples of the functional groups mentioned in the above include the following:

[0044] The alkyl group is not particularly limited, but is preferably an alkyl group having 1 to 18 carbon atoms, and more preferably an alkyl group having 1 to 10 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, a hexyl group, and a decyl group.

[0045] The alkenyl group is not particularly limited, but is preferably an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkenyl group having 2 to 10 carbon atoms. Specific examples include a vinyl group, an allyl group, and a 3-butenyl group.

[0046] The alkynyl group is not particularly limited, but is preferably an alkynyl group having 2 to 18 carbon atoms, and more preferably an alkynyl group having 2 to 10 carbon atoms. Specific examples include an ethynyl group and a prop-2-yn-1-yl group (propargyl group).

[0047] The alkylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkyl group, but for example, an alkylcarbonyl group having 2 to 18 carbon atoms is preferred, and an alkylcarbonyl group having 2 to 10 carbon atoms is more preferred. Specific examples include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a pivaloyl group, a hexanoyl group, an octanoyl group, and a cyclohexylcarbonyl group.

[0048] The alkenylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkenyl group, but for example, an alkenylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkenylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include an acryloyl group, a methacryloyl group, and a crotonoyl group.

[0049] The alkynylcarbonyl group is not particularly limited as long as it is a carbonyl group substituted with an alkynyl group, but for example, an alkynylcarbonyl group having 3 to 18 carbon atoms is preferred, and an alkynylcarbonyl group having 3 to 10 carbon atoms is more preferred. Specific examples include a propioloyl group.

[0050] The average number of the substituents (number of terminal functional groups) at the molecular terminals per molecule of the polyphenylene ether compound is not particularly limited. Specifically, it is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.5 to 3. If the number of terminal functional groups is too small, it tends to be difficult to obtain a cured product with sufficient heat resistance. On the other hand, if the number of terminal functional groups is too large, the reactivity becomes too high, which may cause problems such as reduced shelf life and reduced fluidity of the resin composition. In other words, when such a polyphenylene ether compound is used, insufficient fluidity may cause molding defects such as the generation of voids during multilayer molding, making it difficult to obtain a highly reliable printed wiring board.

[0051] The number of terminal functional groups of a polyphenylene ether compound may be, for example, a numerical value representing the average number of the substituents per molecule of all modified polyphenylene ether compounds present in 1 mole of the polyphenylene ether compound. The number of terminal functional groups can be measured, for example, by measuring the number of hydroxyl groups remaining in the obtained modified polyphenylene ether compound and calculating the difference from the number of hydroxyl groups in the polyphenylene ether before modification. This difference from the number of hydroxyl groups in the polyphenylene ether before modification is the number of terminal functional groups. The number of hydroxyl groups remaining in the modified polyphenylene ether compound can be measured by adding a quaternary ammonium salt (tetraethylammonium hydroxide) that associates with hydroxyl groups to a solution of the modified polyphenylene ether compound and measuring the UV absorbance of the resulting mixed solution.

[0052] Examples of the polyphenylene ether compound of the present embodiment include a modified polyphenylene ether compound represented by the following formula (5) and a modified polyphenylene ether compound represented by the following formula (6). As the polyphenylene ether compound of the present embodiment, these modified polyphenylene ether compounds may be used alone, or these two types of modified polyphenylene ether compounds may be used in combination.

[0053]

[0054]

[0055] In formula (5) and formula (6), R ９ ~R １６ and R １７ ~R ２４ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group. １ and X ２ each independently represents a substituent having a carbon-carbon unsaturated double bond. A and B represent repeating units represented by the following formulas (7) and (8), respectively. In addition, in formula (6), Y represents a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms.

[0056]

[0057]

[0058] In formula (7) and formula (8), m and n each represent an integer of 0 to 20. ２５ ~R ２８ and R ２９ ~R ３２ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group.

[0059] The modified polyphenylene ether compound represented by the formula (5) and the modified polyphenylene ether compound represented by the formula (6) are not particularly limited as long as they satisfy the above-mentioned constitution. Specifically, in the formulas (5) and (6), R ９ ~R １６ and R １７ ~R ２４ As described above, each of R is independent. ９ ~R １６ and R １７ ~R ２４ may be the same group or different groups.９ ~R １６ and R １７ ~R ２４ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0060] In formula (7) and formula (8), m and n each preferably represent a value of 0 to 20, as described above. Furthermore, m and n preferably represent a numerical value such that the sum of m and n is 1 to 30. Therefore, it is more preferable that m represents a value of 0 to 20, n represents a value of 0 to 20, and the sum of m and n represents a value of 1 to 30. R ２５ ~R ２８ and R ２９ ~R ３２ are independent of each other. That is, R ２５ ~R ２８ and R ２９ ~R ３２ may be the same group or different groups. ２５ ~R ２８ and R ２９ ~R ３２ represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, a formyl group, an alkylcarbonyl group, an alkenylcarbonyl group, or an alkynylcarbonyl group, among which a hydrogen atom and an alkyl group are preferred.

[0061] R ９ ~R ３２ is R in the above formula (4). ５ ~R ８ is the same as

[0062] In the formula (6), as described above, Y is a linear, branched, or cyclic hydrocarbon having 20 or less carbon atoms. Examples of Y include a group represented by the following formula (9).

[0063]

[0064] In the formula (9), R ３３ and R ３４are each independently a hydrogen atom or an alkyl group. Examples of the alkyl group include a methyl group. Examples of the group represented by formula (9) include a methylene group, a methylmethylene group, and a dimethylmethylene group, and among these, a dimethylmethylene group is preferred.

[0065] In the formula (5) and the formula (6), X １ and X ２ are each independently a substituent having a carbon-carbon unsaturated double bond. １ and X ２ There are no particular limitations on the substituent X as long as it is a substituent having a carbon-carbon unsaturated double bond. １ and X ２ Examples of the substituents include the substituents represented by the formula (1) and the substituents represented by the formula (2). In the modified polyphenylene ether compound represented by the formula (5) and the modified polyphenylene ether compound represented by the formula (6), X １ and X ２ may be the same substituent or different substituents.

[0066] More specific examples of the modified polyphenylene ether compound represented by the formula (5) include modified polyphenylene ether compounds represented by the following formula (10).

[0067]

[0068] More specific examples of the modified polyphenylene ether compound represented by formula (6) include a modified polyphenylene ether compound represented by formula (11) below and a modified polyphenylene ether compound represented by formula (12) below.

[0069]

[0070]

[0071] In the above formulas (10) and (11), m and n are the same as m and n in the above formulas (7) and (8).１ ~R ３ , p and Z are R in the above formula (1), respectively. １ ~R ３ , s and Z. In the formula (11) and the formula (12), Y is the same as Y in the formula (9). In the formula (12), R ４ is R in the above formula (2). ４ is the same as

[0072] It is believed that by using the modified polyphenylene ether compound as described above, it is possible to improve high Tg and adhesion while maintaining low dielectric properties such as low dielectric constant and excellent heat resistance.

[0073] The modified polyphenylene ether compounds may be used singly or in combination of two or more.

[0074] The polyphenylene ether compound used in the resin composition of this embodiment can be synthesized by a known method, or a commercially available product can be used. Examples of commercially available products include "OPE-2st 1200" and "OPE-2st 2200" manufactured by Mitsubishi Gas Chemical Company, Inc., and "SA9000" manufactured by SABIC Innovative Plastics.

[0075] Hydrocarbon-based compound having a carbon-carbon unsaturated double bond in the molecule The hydrocarbon-based resin that can be used in this embodiment is not particularly limited as long as it is a hydrocarbon-based resin having an unsaturated double bond, and preferred examples thereof include hydrocarbon-based resins such as polyfunctional vinyl aromatic polymers, cyclic polyolefin resins, and vinyl aromatic compound-conjugated diene compound copolymers.

[0076] The polyfunctional vinyl aromatic polymer is preferably a polymer containing at least a polyfunctional vinyl aromatic compound and / or a derivative thereof polymerized therein, and is not particularly limited as long as it is a polymer containing a structure derived from a polyfunctional vinyl aromatic compound and / or a derivative thereof, and may be a polymer containing one or more polyfunctional vinyl aromatic compounds and / or a structure derived from a derivative thereof.

[0077] In addition to the structural units of the polyfunctional vinyl aromatic compound and / or its derivative, the copolymer may further contain one or more structural units derived from a reactive monomer. The reactive monomer is not particularly limited, but may be, for example, a polyfunctional vinyl aromatic copolymer having a structural unit derived from a monovinyl aromatic compound such as styrene.

[0078] More specifically, examples of the polyfunctional vinyl compound include a polyfunctional vinyl compound having two or more vinyl groups in the molecule, such as divinylbenzene, divinylnaphthalene, divinylbiphenyl, and polybutadiene.

[0079] Maleimide Compounds Other than Maleimide Compound (A-1) As the maleimide compound other than the maleimide compound (A-1), any compound having a maleimide group can be used without particular limitation. Specific examples of the maleimide compound include monofunctional maleimide compounds having one maleimide group in the molecule, polyfunctional maleimide compounds having two or more maleimide groups in the molecule, and modified maleimide compounds. Examples of the modified maleimide compound include modified maleimide compounds in which a portion of the molecule is modified with an amine compound, modified maleimide compounds in which a portion of the molecule is modified with a silicone compound, and modified maleimide compounds in which a portion of the molecule is modified with an amine compound and a silicone compound.

[0080] In addition to the above, the resin composition of the present embodiment may contain, as the radical polymerizable compound (A-2), an allyl compound, a vinyl compound, a methacrylate compound, an acrylate compound, an acenaphthylene compound, or the like.

[0081] The content of the radical polymerizable compound (A) in the resin composition of this embodiment is preferably about 50 to 100 mass % and more preferably about 60 to 80 mass % based on the total resin components in the resin composition (organic resin components in the resin composition). This is believed to more reliably achieve low dielectric properties in the cured product.

[0082] The content of the N-phenylmaleimide compound (A-1) is preferably 35% by mass or more based on the total amount of the radical polymerizable compound (A). This more reliably provides a resin composition that yields a cured product that has excellent heat resistance and is resistant to deterioration of low dielectric properties at high temperatures. The content of the N-phenylmaleimide compound (A-1) is more preferably 40% by mass or more. There is no particular upper limit to the content, and it may be 100% by mass based on the total amount of the radical polymerizable compound (A).

[0083] (Other: Thermosetting Resin) The resin composition of the present embodiment may further contain a thermosetting resin for improving the curing reaction of the radically polymerizable compound (A) containing the maleimide compound (A-1).

[0084] Examples of thermosetting resins that can be used in this embodiment include epoxy compounds, polyphenylene ether compounds, cyanate ester compounds, phenol compounds, benzoxazine compounds, active ester compounds, etc. Among these, the resin composition of this embodiment preferably contains a benzoxazine compound (C) from the viewpoints of curability and moldability.

[0085] As the benzoxazine compound (C), it is preferable to use a benzoxazine compound having an allyl group. As the benzoxazine compound (C), commercially available products such as P-d, Fa, and ALP-d manufactured by Shikoku Chemical Industries, Ltd. may be used.

[0086] When the resin composition of this embodiment contains a benzoxazine compound (C), the content thereof is preferably 50 mass% or less relative to the total amount of the radical polymerizable compound (A) and the benzoxazine compound (C). This is believed to more reliably achieve the effects described above. Furthermore, the ratio of the radical polymerizable compound (A):benzoxazine compound (C) in the resin composition is preferably about 95:5 to 50:50 by mass.

[0087] (Inorganic Filler) The resin composition according to this embodiment contains a boron nitride filler (B) as an inorganic filler. The boron nitride filler (B) contains a scaly boron filler (B-1). By including such a boron nitride filler (B), the resin composition according to this embodiment has high thermal conductivity in its cured form.

[0088] Scaly boron filler (B-1) The scaly boron filler (B-1) is not particularly limited as long as it is a non-aggregated scaly boron filler. The type of boron nitride filler is not particularly limited, and examples include hexagonal normal pressure phase (h-BN) and cubic high pressure phase (c-BN), which are commonly used as inorganic fillers.

[0089] In this specification, the term "aggregation of boron filler" does not mean a state in which particles are gathered together due to interactions between particles, but rather a state in which boron nitride particles as primary particles are aggregated using an organic binder to form secondary particles. In other words, the non-aggregated scaly boron filler (B-1) refers to scaly boron nitride that does not contain an organic binder and does not form secondary particles.

[0090] In this embodiment, the particle size (D50) of the scaly boron filler (B-1) at 50% cumulative total in the particle size distribution is preferably 2.0 to 20.0 μm. Furthermore, the particle size (D90) at 90% cumulative total in the particle size distribution is preferably 5.0 to 50.0 μm. It is believed that the use of a scaly boron filler (B-1) having such a D50 and / or D90 can provide a resin composition with even better moldability. The boron nitride filler disclosed in Patent Document 2, as mentioned above, does not address its particle size. While the larger the particle size of the boron nitride filler, the higher the thermal conductivity, the more difficult it is to limit the thickness of the substrate. Depending on the particle size of the filler, concerns may arise regarding moldability, insulation, drilling processability, and the like, which may limit the applications of the substrate material. In contrast, by using the scaly boron filler (B-1) having the particle size described above, there are advantages in that it is excellent in formability and the range of applicable substrate thicknesses is widened (it can also be used for thin plates).

[0091] The particle size (D50) is more preferably in the range of 5 to 15 μm, and the particle size (D90) is more preferably in the range of 10 to 30 μm.

[0092] In this specification, the particle size distribution is a value measured by particle size distribution measurement using a laser diffraction / scattering method, and can be measured using, for example, a laser diffraction / scattering particle size distribution measuring device "LA-960V2" (manufactured by HORIBA, Ltd.) used in the examples described later.

[0093] The content of the scaly boron filler (B-1) is preferably 70 to 250 parts by mass, and more preferably 100 to 200 parts by mass, relative to 100 parts by mass of the total amount of the boron nitride filler (B). That is, the boron nitride filler (B) of this embodiment may be composed solely of the scaly boron filler (B-1), or may contain other boron nitride fillers. Examples of boron nitride fillers other than the scaly boron filler (B-1) include agglomerated boron nitride fillers.

[0094] Agglomerated boron nitride fillers contain boron nitride particles as primary particles, and the primary particles are aggregated to form secondary particles using an organic binder. There are no particular limitations on the method for obtaining agglomerated boron nitride fillers, but they can be obtained, for example, by granulating boron nitride primary particles into spherical particles using an organic binder component, followed by firing at high temperature, pulverizing, and classifying.

[0095] In a preferred embodiment, from the viewpoint of fluidity, the resin composition of the present embodiment preferably does not contain an aggregated boron nitride filler, i.e., the entire amount of the boron nitride filler (B) is preferably the scaly boron filler (B-1).

[0096] In the resin composition of this embodiment, the total content of the boron nitride filler (B) is preferably 70 parts by mass or more and 250 parts by mass or less per 100 parts by mass of the radically polymerizable compound (A). This is believed to enable both high thermal conductivity and excellent moldability to be achieved. A more preferred range for the content is 100 parts by mass or more and 200 parts by mass or less.

[0097] Silica Filler (D) The resin composition of this embodiment preferably further contains a silica filler (D) as an inorganic filler other than the boron nitride filler (B). The inclusion of the silica filler (D) has the advantage of increasing the amount of inorganic filler filled and reducing the coefficient of thermal expansion (CTE).

[0098] The silica filler (D) used in this embodiment is not particularly limited as long as it can be used as an inorganic filler. The silica in this embodiment may be surface-treated or may not be surface-treated. Examples of the surface treatment include treatment with a silane coupling agent.

[0099] Examples of the silane coupling agent include silane coupling agents having at least one functional group selected from the group consisting of a vinyl group, a styryl group, a methacryloyl group, an acryloyl group, and a phenylamino group. That is, the silane coupling agent includes compounds having at least one reactive functional group selected from a vinyl group, a styryl group, a methacryloyl group, an acryloyl group, and a phenylamino group, and further having a hydrolyzable group such as a methoxy group or an ethoxy group.

[0100] Examples of the silane coupling agent include those having a vinyl group, such as vinyltriethoxysilane and vinyltrimethoxysilane. Examples of the silane coupling agent include those having a styryl group, such as p-styryltrimethoxysilane and p-styryltriethoxysilane. Examples of the silane coupling agent include those having a methacryloyl group, such as 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropylethyldiethoxysilane. Examples of the silane coupling agent include those having an acryloyl group, such as 3-acryloxypropyltrimethoxysilane and 3-acryloxypropyltriethoxysilane. Examples of the silane coupling agent include those having a phenylamino group, such as N-phenyl-3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltriethoxysilane.

[0101] It is preferable that the particle size (D50) at 50% cumulative total in the particle size distribution of the silica filler (D) is 0.5 to 10.0 μm, and the particle size (D90) at 90% cumulative total in the particle size distribution is 50.0 μm or less. This is believed to more reliably achieve the above-mentioned effects obtained by the silica filler (D). The particle size (D50) is more preferably in the range of 1 to 6 μm, and the particle size (D90) is more preferably in the range of 5 to 45 μm.

[0102] The specific surface area of ​​the silica filler (D) is 0.5 to 15 m ２ / g, and 0.5 to 10 m ２ It is more preferable that the solubility is about 1 / g.

[0103] The content of the silica filler (D) is preferably 50 parts by mass or more and 150 parts by mass or less, and more preferably 75 parts by mass or more and 125 parts by mass or less, per 100 parts by mass of the resin component including the radical polymerizable compound (A).

[0104] The resin composition of this embodiment may further contain an inorganic filler other than the boron nitride filler (B) and the silica filler (D). The inorganic filler other than boron nitride and silica is not particularly limited as long as it can be used as an inorganic filler contained in the resin composition. Specific examples include metal oxides such as alumina, titanium oxide, magnesium oxide, and mica, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, talc, aluminum borate, barium sulfate, aluminum nitride, silicon nitride, magnesium carbonate such as anhydrous magnesium carbonate, and calcium carbonate. Among these, anhydrous magnesium carbonate, alumina, and silicon nitride are preferred.

[0105] The inorganic fillers other than boron nitride and silica may also be surface-treated or untreated. Examples of the surface treatment include treatment with a silane coupling agent.

[0106] The total content of the inorganic filler in the resin composition of this embodiment is preferably 50 to 400 parts by mass, and more preferably 80 to 250 parts by mass, per 100 parts by mass of the solid content of the resin composition of this embodiment. Here, the solid content of the resin composition means the solid content of the resin remaining after removing volatile components such as the solvent from the resin composition.

[0107] (Reaction initiator) The resin composition of the present embodiment may further contain a reaction initiator. The radical polymerization (curing) reaction of the resin composition can proceed even without a reaction initiator. However, depending on the process conditions, it may be difficult to raise the temperature high enough for curing to proceed, so a reaction initiator may be added.

[0108] The reaction initiator is not particularly limited as long as it can accelerate the curing reaction of the resin composition. Specific examples include metal oxides, azo compounds, and peroxides, and preferably includes at least one of peroxides and azo compounds.

[0109] Specific examples of metal oxides include metal carboxylates.

[0110] Examples of organic peroxides include α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, benzoyl peroxide, 3,3',5,5'-tetramethyl-1,4-diphenoquinone, chloranil, 2,4,6-tri-t-butylphenoxyl, t-butylperoxyisopropyl monocarbonate, and azobisisobutyronitrile.

[0111] Specific examples of the azo compound include 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), and 2,2'-azobis(2-methylbutyronitrile).

[0112] Among these, preferred reaction initiators are 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(N-butyl-2-methylpropionamide), etc. These reaction initiators have little effect on dielectric properties. In addition, because the reaction initiation temperature is relatively high, promotion of the curing reaction can be suppressed when curing is not necessary, such as during prepreg drying, which has the advantage of suppressing deterioration in the shelf life of the resin composition.

[0113] The above-mentioned reaction initiators may be used alone or in combination of two or more kinds.

[0114] When the resin composition of the present embodiment contains the reaction initiator, the content thereof is not particularly limited, but is, for example, preferably 0.1 to 5.0 parts by mass, more preferably 0.5 to 3.0 parts by mass, and even more preferably 0.5 to 2.0 parts by mass, relative to 100 parts by mass of the radical polymerizable compound (A).

[0115] (Other Components) The resin composition according to the present embodiment may contain other components (other components) than the above-described components, as needed, within the scope of not impairing the effects of the present invention. Examples of other components contained in the resin composition according to the present embodiment may further include additives such as silane coupling agents, flame retardants, antifoaming agents, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, dyes, pigments, dispersants, and lubricants.

[0116] (Production Method) The method for producing the resin composition is not particularly limited, and examples thereof include a method in which the radical polymerizable compound (A) and, if necessary, other resin components are mixed, and then an inorganic filler is added, etc. Specifically, in the case of obtaining a varnish-like composition containing an organic solvent, the method described in the description of the prepreg below, etc., can be used.

[0117] By using the resin composition according to this embodiment, a prepreg, a metal-clad laminate, a wiring board, a resin-coated metal foil, and a resin-coated film can be obtained as follows.

[0118] 1 is a schematic cross-sectional view showing an example of a prepreg 1 according to an embodiment of the present invention. In the following description, the respective reference numerals represent: 1 prepreg, 2 resin composition or semi-cured resin composition, 3 fibrous base material, 11 metal-clad laminate, 12 insulating layer, 13 metal foil, 14 wiring, 21 wiring board, 31 resin-coated metal foil, 32, 42 resin layer, 41 resin-coated film, and 43 support film.

[0119] 1, the prepreg 1 according to this embodiment comprises the resin composition or a semi-cured product of the resin composition 2, and a fibrous base material 3. This prepreg 1 comprises the resin composition or a semi-cured product of the resin composition 2, and the fibrous base material 3 present in the resin composition or the semi-cured product of the resin composition 2.

[0120] In this embodiment, the semi-cured product refers to a resin composition that has been partially cured to the extent that it can be further cured. That is, the semi-cured product refers to a resin composition that has been semi-cured (B-staged). For example, when a resin composition is heated, the viscosity initially gradually decreases, then curing begins, and then curing begins again, and the viscosity gradually increases. In such a case, the semi-cured state may refer to a state between when the viscosity begins to increase and when the composition is completely cured.

[0121] Furthermore, the prepreg obtained using the resin composition according to this embodiment may comprise a semi-cured product of the resin composition as described above, or may comprise the uncured resin composition itself. That is, it may be a prepreg comprising a semi-cured product of the resin composition (the resin composition in B stage) and a fibrous base material, or a prepreg comprising the resin composition before curing (the resin composition in A stage) and a fibrous base material. The resin composition or the semi-cured product of the resin composition may be obtained by drying or heat-drying the resin composition.

[0122] When producing a prepreg, the resin composition 2 is often prepared in a varnish form and used to impregnate the fibrous base material 3, which is the base material for forming the prepreg. That is, the resin composition 2 is usually often a resin varnish prepared in a varnish form. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows.

[0123] First, each component of the resin composition that is soluble in an organic solvent is added to the organic solvent and dissolved. Heating may be performed as necessary. Subsequently, components that are insoluble in the organic solvent (e.g., inorganic fillers) are added as needed, and the mixture is dispersed using a disperser or the like until a predetermined dispersion state is achieved, thereby preparing a varnish-like resin composition. The organic solvent used here is not particularly limited as long as it dissolves the radical polymerizable compound and the like and does not inhibit the curing reaction. Specific examples include toluene and methyl ethyl ketone (MEK).

[0124] The method for producing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when producing the prepreg, the resin composition used in the present embodiment is often prepared in the form of a varnish as described above and used as a resin varnish.

[0125] Specific examples of the fibrous substrate include glass cloth, aramid cloth, polyester cloth, glass nonwoven fabric, aramid nonwoven fabric, polyester nonwoven fabric, pulp paper, and linter paper. The use of glass cloth provides a laminate with excellent mechanical strength, and flattened glass cloth is particularly preferred. A specific example of the flattening process is a method in which glass cloth is continuously pressed with a press roll at an appropriate pressure to compress the yarns flat. The thickness of commonly used fibrous substrates is, for example, 0.01 mm or more and 0.3 mm or less.

[0126] The method for producing the prepreg is not particularly limited as long as it can produce the prepreg. Specifically, when producing the prepreg, the resin composition according to the present embodiment is often prepared in the form of a varnish as described above and used as a resin varnish.

[0127] The prepreg 1 can be produced, for example, by impregnating a fibrous substrate 3 with a resin composition 2, for example, a resin composition 2 prepared in a varnish form, followed by drying. The resin composition 2 is impregnated into the fibrous substrate 3 by immersion, coating, or the like. Impregnation can be repeated multiple times as necessary. In this case, by repeating the impregnation using multiple resin compositions with different compositions and concentrations, it is possible to adjust the final composition and impregnation amount to the desired one.

[0128] The fibrous substrate 3 impregnated with the resin composition (resin varnish) 2 is heated under desired conditions, for example, at 80°C to 180°C for 1 minute to 10 minutes. This heating produces a prepreg 1 in an uncured (A-stage) or semi-cured (B-stage) state. The heating also volatilizes the organic solvent from the resin varnish, reducing or eliminating the organic solvent.

[0129] [Metal-clad laminate] FIG. 2 is a schematic cross-sectional view showing an example of a metal-clad laminate 11 according to an embodiment of the present invention.

[0130] As shown in FIG. 2, the metal-clad laminate 11 is composed of an insulating layer 12 containing a cured product of the prepreg 1 shown in FIG. 1 and a metal foil 13 laminated together with the insulating layer 12. That is, the metal-clad laminate 11 has an insulating layer 12 containing a cured product of a resin composition and a metal foil 13 provided on the insulating layer 12. The insulating layer 12 may be composed of a cured product of the resin composition or a cured product of the prepreg. The thickness of the metal foil 13 varies depending on the performance required of the final wiring board and is not particularly limited. The thickness of the metal foil 13 can be appropriately set depending on the desired purpose, and is preferably, for example, 0.2 to 70 μm. Examples of the metal foil 13 include copper foil and aluminum foil. When the metal foil is thin, it may be a carrier-attached copper foil equipped with a release layer and a carrier to improve handling.

[0131] The method for producing the metal-clad laminate 11 is not particularly limited as long as it can produce the metal-clad laminate 11. Specifically, a method for producing the metal-clad laminate 11 using a prepreg 1 can be used. Examples of such a method include stacking one or more prepregs 1, placing a metal foil 13 such as copper foil on both sides or one side of the prepreg 1, and then heat-pressing and molding the metal foil 13 and the prepreg 1 to form an integrated laminate, thereby producing a double-sided or single-sided metal foil-clad laminate 11. That is, the metal-clad laminate 11 can be obtained by laminating the metal foil 13 on the prepreg 1 and then heat-pressing and molding the laminate. The heat-pressing conditions can be appropriately set depending on the thickness of the metal-clad laminate 11 to be produced, the type of composition of the prepreg 1, and other factors. For example, the temperature can be 170 to 230°C, the pressure can be 3 to 5 MPa, and the time can be 60 to 150 minutes. The metal-clad laminate can also be produced without using a prepreg. For example, a method may be used in which a varnish-like resin composition is applied onto a metal foil to form a layer containing the resin composition on the metal foil, and then the layer is heated and pressed.

[0132] [Wiring Board] FIG. 3 is a schematic cross-sectional view showing an example of a wiring board 21 according to an embodiment of the present invention.

[0133] 3, wiring board 21 according to this embodiment is composed of insulating layer 12, which is formed by curing prepreg 1 shown in FIG. 1, and wiring 14, which is laminated together with insulating layer 12 and formed by partially removing metal foil 13. That is, wiring board 21 has insulating layer 12 containing a cured product of a resin composition, and wiring 14 provided on insulating layer 12. Insulating layer 12 may be made of a cured product of the resin composition, or may be made of a cured product of the prepreg.

[0134] The method for manufacturing the wiring board 21 is not particularly limited as long as the wiring board 21 can be manufactured. Specific examples include a method of manufacturing the wiring board 21 using the prepreg 1. Examples of this method include a method of manufacturing the wiring board 21 in which wiring is provided as a circuit on the surface of the insulating layer 12 by etching the metal foil 13 on the surface of the metal-clad laminate 11 manufactured as described above. That is, the wiring board 21 is obtained by forming a circuit by partially removing the metal foil 13 on the surface of the metal-clad laminate 11. In addition to the above methods, examples of the method for forming a circuit include circuit formation by a semi-additive process (SAP) or a modified semi-additive process (MSAP).

[0135] [Resin-Coated Metal Foil] FIG. 4 is a schematic cross-sectional view showing an example of a resin-coated metal foil 31 according to this embodiment.

[0136] As shown in Fig. 4, the resin-coated metal foil 31 according to this embodiment comprises a resin layer 32 containing the resin composition or a semi-cured product of the resin composition, and a metal foil 13. The resin-coated metal foil 31 has the metal foil 13 on the surface of the resin layer 32. That is, the resin-coated metal foil 31 comprises the resin layer 32 and the metal foil 13 laminated together with the resin layer 32. The resin-coated metal foil 31 may also comprise another layer between the resin layer 32 and the metal foil 13.

[0137] The resin layer 32 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated metal foil 31 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in B-stage) and a metal foil, or a resin layer containing the resin composition before curing (the resin composition in A-stage) and a metal foil. The resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0138] The metal foil may be any metal foil used in metal-clad laminates, including, for example, copper foil and aluminum foil.

[0139] The resin-coated metal foil 31 and the resin-coated film 41 may be provided with a cover film or the like, as necessary. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include polyolefin film, polyester film, polymethylpentene film, and films formed by providing a release agent layer on these films.

[0140] The method for producing the resin-coated metal foil 31 is not particularly limited as long as it can produce the resin-coated metal foil 31. Examples of methods for producing the resin-coated metal foil 31 include a method of applying the varnish-like resin composition (resin varnish) to the metal foil 13 and heating it. The varnish-like resin composition is applied to the metal foil 13 using, for example, a bar coater. The applied resin composition is heated, for example, at 80°C or higher and 180°C or lower for 1 minute or longer and 10 minutes or shorter. The heated resin composition is formed on the metal foil 13 as an uncured resin layer 32. Note that the heating volatilizes the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0141] [Resin-Coated Film] FIG. 5 is a schematic cross-sectional view showing an example of a resin-coated film 41 according to this embodiment.

[0142] 5 , the resin-included film 41 according to this embodiment includes a resin layer 42 containing the resin composition or a semi-cured product of the resin composition, and a support film 43. The resin-included film 41 includes the resin layer 42 and the support film 43 laminated together with the resin layer 42. The resin-included film 41 may include another layer between the resin layer 42 and the support film 43.

[0143] The resin layer 42 may contain a semi-cured product of the resin composition as described above, or may contain the uncured resin composition. That is, the resin-coated film 41 may comprise a resin layer containing a semi-cured product of the resin composition (the resin composition in B-stage) and a support film, or a resin-coated film comprising a resin layer containing the resin composition before curing (the resin composition in A-stage) and a support film. The resin layer may contain the resin composition or a semi-cured product of the resin composition, and may or may not contain a fibrous substrate. The resin composition or the semi-cured product of the resin composition may be the resin composition that has been dried or heat-dried. The fibrous substrate may be the same as the fibrous substrate of a prepreg.

[0144] Any support film used for a resin-coated film can be used as the support film 43. Examples of the support film include electrically insulating films such as polyester film, polyethylene terephthalate (PET) film, polyimide film, polyparabanic acid film, polyether ether ketone film, polyphenylene sulfide film, polyamide film, polycarbonate film, and polyarylate film.

[0145] The resin-coated film 41 may be provided with a cover film or the like as necessary. By providing a cover film, it is possible to prevent the inclusion of foreign matter, etc. The cover film is not particularly limited, but examples thereof include a polyolefin film, a polyester film, and a polymethylpentene film.

[0146] The support film and cover film may be subjected to surface treatment such as matte treatment, corona treatment, release treatment, and roughening treatment, if necessary.

[0147] The method for producing the resin-coated film 41 is not particularly limited as long as it can produce the resin-coated film 41. Examples of methods for producing the resin-coated film 41 include a method in which the varnish-like resin composition (resin varnish) is applied to a support film 43 and heated. The varnish-like resin composition is applied to the support film 43 using, for example, a bar coater. The applied resin composition is heated, for example, at 80°C or higher and 180°C or lower for 1 minute or longer and 10 minutes or shorter. The heated resin composition is formed on the support film 43 as an uncured resin layer 42. The heating can volatilize the organic solvent from the resin varnish, thereby reducing or removing the organic solvent.

[0148] The prepreg, resin-coated film, and resin-coated metal foil obtained using the resin composition of this embodiment have excellent low dielectric properties and high thermal conductivity when cured, and the low dielectric properties are resistant to deterioration even at high temperatures, making them extremely useful for industrial applications. Metal-clad laminates and wiring boards having an insulating layer containing a cured product of the resin composition of this embodiment also have similar advantages.

[0149] This specification discloses various aspects of the technology as described above, but the main technologies among them are summarized below.

[0150] A resin composition according to a first aspect of the present invention is a resin composition comprising a radically polymerizable compound (A) and a boron nitride filler (B), wherein the radically polymerizable compound (A) comprises an N-phenylmaleimide compound (A-1) that does not contain an alkyl group having two or more carbon atoms, and the boron nitride filler (B) comprises a scaly boron nitride filler (B-1), and wherein a cured product of the resin composition exhibits a rate of change in dielectric loss tangent (ΔDf) defined by the following formula (1) of 50% or less:

[0151]

[0152] (In formula (1), Df １ is the dielectric loss tangent at 10 GHz of the cured product before heat treatment, and Df ２ is the dielectric loss tangent at 10 GHz of the cured product after heat treatment at 188°C for 500 hours.

[0153] A resin composition related to a second aspect of the present invention is the resin composition of the first aspect, wherein the content of the N-phenylmaleimide compound (A-1) is 35 mass% or more based on the total amount of the radical polymerizable compound (A).

[0154] A resin composition according to a third aspect of the present invention is the resin composition of the first or second aspect, wherein the particle size distribution of the scaly boron nitride filler (B-1) has a particle size (D50) at an integrated value of 50% of the particle size distribution of 2.0 to 20.0 μm.

[0155] A resin composition according to a fourth aspect of the present invention is the resin composition according to any one of the first to third aspects, wherein the particle size distribution of the flaky boron nitride filler (B-1) has a particle size (D90) at 90% cumulative total of 5.0 to 50.0 μm.

[0156] A resin composition according to a fifth aspect of the present invention is the resin composition of any one of the first to fourth aspects, wherein the content of the boron nitride filler (B) is 70 parts by mass or more and 250 parts by mass or less per 100 parts by mass of the radical polymerizable compound (A).

[0157] A resin composition according to a sixth aspect of the present invention is the resin composition of any one of the first to fifth aspects, further comprising a benzoxazine compound (C).

[0158] A resin composition according to a seventh aspect of the present invention is the resin composition of the sixth aspect, wherein the content of the benzoxazine compound (C) is 50 mass% or less relative to the total amount of the radical polymerizable compound (A) and the benzoxazine compound (C).

[0159] The resin composition according to an eighth aspect of the present invention is the resin composition according to any one of the first to seventh aspects, further comprising a silica filler (D), the content of which is 50 parts by mass or more and 150 parts by mass or less relative to 100 parts by mass of the radical polymerizable compound (A).

[0160] A resin composition according to a ninth aspect of the present invention is the resin composition of the eighth aspect, wherein the particle size distribution of the silica filler (D) has a particle size (D50) at 50% cumulative total of 0.5 to 10.0 μm and a particle size (D90) at 90% cumulative total of 50.0 μm or less.

[0161] A resin composition according to a tenth aspect of the present invention is the resin composition of any one of the first to ninth aspects, further comprising a radical polymerizable compound (A-2) different from the maleimide compound (A-1).

[0162] The resin composition according to an eleventh aspect of the present invention is the resin composition according to any one of the first to tenth aspects, wherein the dielectric loss tangent (Df １ ) is 0.0045 or less.

[0163] A prepreg according to a twelfth aspect of the present invention comprises the resin composition of any one of the first to eleventh aspects or a semi-cured product of the resin composition, and a fibrous base material.

[0164] A resin-coated film according to a thirteenth aspect of the present invention comprises a resin layer containing the resin composition of any one of the first to eleventh aspects or a semi-cured product of the resin composition, and a support film.

[0165] A resin-coated metal foil according to a fourteenth aspect of the present invention comprises a resin layer containing the resin composition of any one of the first to eleventh aspects or a semi-cured product of the resin composition, and a metal foil.

[0166] A metal-clad laminate according to a fifteenth aspect of the present invention has an insulating layer containing a cured product of the resin composition according to any one of the first to eleventh aspects or a cured product of the prepreg according to the twelfth aspect, and a metal foil.

[0167] A wiring board according to a sixteenth aspect of the present invention has an insulating layer containing a cured product of the resin composition of any one of the first to eleventh aspects or a cured product of the prepreg of the twelfth aspect, and wiring.

[0168] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0169] First, in this example, each component used in preparing the resin composition will be described.

[0170] <Radical Polymerizable Compound (A)> (Maleimide Compound (A-1)) N-Phenylmaleimide compound 1: bismaleimide resin (MIR-5000-60T, manufactured by Nippon Kayaku Co., Ltd., molecular weight approximately 600) N-Phenylmaleimide compound 2: bismaleimide resin (MIR-3000-70MT, manufactured by Nippon Kayaku Co., Ltd., molecular weight approximately 800) (Maleimide compounds other than (A-1)) Maleimide compound 3: bismaleimide resin (BMI-5100, manufactured by Daiwa Kasei Co., Ltd., molecular weight approximately 450) Maleimide compound 4: bismaleimide resin (BMI-TMH, manufactured by Daiwa Kasei Co., Ltd., molecular weight approximately 300) (Radical Polymerizable Compound (A-2)) PPE1: Polyphenylene ether compound having a methacryloyl group at the end (SA9000 manufactured by SABIC Innovative Plastics, weight average molecular weight Mw 2000, number of terminal functional groups 2) PPE2: Polyphenylene ether compound having a vinylbenzyl group (ethenylbenzyl group) at the end (OPE-2st 1200, Mn 1200 manufactured by Mitsubishi Gas Chemical Company, Inc.)

[0171] <Other thermosetting resins, etc.> Benzoxazine compound (C): (ALP-d manufactured by Shikoku Chemical Industry Co., Ltd.) TAIC: triallyl isocyanurate (TAIC manufactured by Nippon Chemical Industry Co., Ltd.) <Reaction initiator> Organic peroxide: PBP (1,3-bis(butylperoxyisopropyl)benzene; Perbutyl P manufactured by NOF Corporation)

[0172] <Inorganic filler> (Boron nitride filler (B)) Flake boron nitride filler (B-1): Flake boron nitride 1: "SGP" manufactured by Denka Company Limited. Flake boron nitride 2: "HGP" manufactured by Denka Company Limited. Flake boron nitride 3: "XGP" manufactured by Denka Company Limited. (Silica filler (D)) Silica: "FB-7SDC" manufactured by Denka Company Limited.

[0173] [Examples 1 to 10 and Comparative Examples 1 to 7] (Preparation Method) First, each component other than the inorganic filler was added to an organic solvent in the composition (parts by mass, solids content) shown in Tables 1 and 2 and mixed. The mixture was stirred for 60 minutes. Thereafter, the filler (parts by mass) was added to the resulting liquid, and the amount of organic solvent added was adjusted so that the solids concentration of the resin composition after dispersion was 65 parts by mass. After that, the mixture was stirred for 60 minutes to disperse the filler, thereby obtaining a varnish-like resin composition (varnish). Note that toluene or MEK was used as the organic solvent.

[0174] Next, an evaluation substrate (cured prepreg) was obtained as follows.

[0175] A prepreg was produced by impregnating a fibrous substrate (glass cloth: #1078 type, L glass, manufactured by Asahi Kasei Corporation) with the obtained varnish and then heating and drying for 3 minutes at 120°C. Four sheets of each obtained prepreg were then stacked, and copper foil (FV-WS copper foil, thickness: 35 μm, manufactured by Furukawa Electric Co., Ltd.) was laminated on both sides. The laminate was heated to a temperature of 200°C at a heating rate of 4°C / min, and heated and pressed at 200°C for 120 minutes under a pressure of 3 MPa to produce a copper-clad laminate with a thickness of approximately 500 μm.

[0176] Test Example 1 In the measurement of thermal conductivity described below, cured prepregs having three different thicknesses were used as samples, and in the evaluation tests of dielectric properties (dielectric constant) and moldability, a copper-clad laminate having four prepregs from which the copper foil had been removed (cured prepreg) was used.

[0177] Each of the evaluation samples prepared as described above was evaluated by the following methods.

[0178] [Dielectric Properties (Dielectric Constant and Dielectric Loss Tangent)] The dielectric constant (Dk) and dielectric loss tangent (Df) of the evaluation substrate (cured prepreg) at 10 GHz were measured by a cavity resonator perturbation method. Specifically, the dielectric loss tangent of the evaluation substrate at 10 GHz was measured using a network analyzer (N5230A manufactured by Keysight Technologies, Inc.). The pass criteria in this example were Dk<4.0 and Df≦0.0045. The measured Df was used as the Df when calculating the rate of change described below.１ It was decided.

[0179] [Thermal Conductivity] The thermal conductivity of the obtained evaluation substrate (cured prepreg) was measured by a method conforming to ASTM D5470. Specifically, the thermal conductivity of the obtained evaluation substrate was measured using a thermal property evaluation device (T3Ster DynTIM Tester manufactured by Mentor Graphics). The pass criterion for thermal conductivity in this example was set to 0.7 W / m K or more.

[0180] [Change in Dielectric Loss Tangent (ΔDf)] The obtained evaluation substrate (cured prepreg) was subjected to heat treatment at 188°C for 500 hours using a dryer. The dielectric loss tangent of the cured product after the heat treatment was measured in the same manner as above, and the resulting value was recorded as Df. ２ The above Df １ and Df ２ Using the values ​​of (a) and (b), the rate of change in dielectric tangent (ΔDf) was calculated by the following formula (1).

[0181]

[0182] In this test, a change rate of 25% or less was judged as "good," a change rate of 50% or less was judged as "pass," and a change rate of more than 50% was judged as "fail."

[0183] [Particle Size Distribution of Inorganic Filler] The particle size distribution of the inorganic filler in each example and comparative example was determined by measurement using a laser diffraction / scattering particle size distribution analyzer LA-960V2 (manufactured by Horiba, Ltd.). The specifications of the device are as follows: Measurement principle: Mie scattering theory Measurement method: Flow measurement Measurement range: 0.01 μm to 5000 μm Light source: LD (650 nm), approximately 5 mW, LED (405 mm), approximately 3 mW Detector: 1 ring-shaped 64-segment silicon photodiode, 5 4-channel array detectors, 3 silicon photodetectors Refractive index: 2.250-0.005i The specifications of the measurement unit (circulation system) are as follows: Dispersion: Ultrasonic probe Circulation: Centrifugal pump Agitation: Rotating blade Flow cell material: Synthetic quartz The particle size distribution measurement conditions are as follows:

[0184] Each measurement sample was placed in a flow cell via a sample bath using toluene as a dispersion solvent, and laser diffraction / scattering particle size distribution measurement was performed in a stirred state.

[0185] The particle size distribution was analyzed and calculated using the analysis software LA-960 for Windows attached to the LA-960V2, and the D50 and D90 of each were determined.

[0186] [Specific Surface Area of ​​Inorganic Filler] The specific surface area of ​​each inorganic filler was measured by the BET method using a fully automatic gas adsorption measuring device "autosorb-iQ" (manufactured by Anton Paar Japan Co., Ltd.).

[0187] The results of the above evaluations are shown in Tables 1 and 2.

[0188]

[0189]

[0190] (Discussion) As can be seen from Table 1, in all of the examples in which the resin composition of the present invention was used, it was confirmed that a cured product having low dielectric properties (dielectric constant and dielectric dissipation factor) and high thermal conductivity could be obtained, and that a resin composition whose low dielectric properties (low dielectric dissipation factor) are resistant to deterioration even at high temperatures could be provided.

[0191] On the other hand, as shown in Table 2, in Comparative Examples 1 to 6, which did not contain the N-phenylmaleimide compound (A-1) or contained only a small amount thereof, the rate of change in the dielectric loss tangent due to heat treatment was high, and it was confirmed that low dielectric properties could not be maintained at high temperatures. Furthermore, in Comparative Example 7, which did not contain the boron nitride filler (B), sufficient thermal conductivity could not be obtained.

[0192] (Test Example 2) [Moldability] The copper-clad laminates (evaluation substrates of Examples 1 to 10) having a thickness of approximately 500 μm produced as described above were inspected for appearance and cross section, and the presence or absence of voids or smears was confirmed using a scanning electron microscope (S-3000N, manufactured by Hitachi High-Tech Fielding Corporation). Those without voids or smears were judged to be acceptable, and those with voids or smears were judged to be unacceptable.

[0193] Furthermore, a copper clad laminate was prepared in the same manner as above, except that the thickness was adjusted to about 400 μm by adjusting the viscosity of the obtained varnish, and the laminate was evaluated in the same manner as above. The absence of voids and smears was regarded as a pass criterion, and the presence of voids and smears was regarded as a fail.

[0194] Then, as a comprehensive judgment, those that had no voids or smears under both conditions (plate thickness 500 μm and plate thickness 400 μm) were rated as "pass", and those that had voids or smears under either condition were rated as "fail".

[0195] The results are shown in Table 3.

[0196]

[0197] (Discussion) From the results in Table 3, it was confirmed that excellent moldability was achieved when the particle sizes (D50 and D90) of the scaly boron nitride filler (B-1) were within the specified ranges. It is considered that the poor moldability was due to the use of a scaly boron nitride filler (B-1) with a relatively large particle size in Example 10.

[0198] This application is based on Japanese Patent Application No. 2023-203237, filed on November 30, 2023, the contents of which are incorporated herein by reference.

[0199] In order to express the present invention, the present invention has been properly and sufficiently described above through embodiments with reference to specific examples, drawings, etc., but it should be recognized that those skilled in the art can easily make changes and / or improvements to the above-described embodiments. Therefore, unless changes or improvements made by those skilled in the art deviate from the scope of the claims set forth in the claims, such changes or improvements are construed as being encompassed within the scope of the claims.

[0200] The present invention has wide industrial applicability in technical fields related to electronic materials, electronic devices, optical devices, and the like.

Claims

1. A resin composition comprising a radically polymerizable compound (A) and a boron nitride filler (B), wherein the radically polymerizable compound (A) comprises an N-phenylmaleimide compound (A-1) that does not contain an alkyl group having two or more carbon atoms, and the boron nitride filler (B) comprises a flaky boron nitride filler (B-1), and in a cured product of the resin compound, the rate of change in dielectric tangent (ΔDf) defined by the following formula (1) is 50% or less. (In formula (1), Df １ is the dielectric tangent at 10 GHz of the cured product before heat treatment, and Df ２ is the dielectric tangent at 10 GHz of the cured product after heat treatment at 188°C for 500 hours.

2. The resin composition according to claim 1, wherein the content of the N-phenylmaleimide compound (A-1) is 35 mass% or more based on the total amount of the radical polymerizable compound (A).

3. The resin composition according to claim 1, wherein the particle size distribution of the scaly boron nitride filler (B-1) is such that the particle size (D50) at an integrated value of 50% is 2.0 to 20.0 μm.

4. The resin composition according to claim 1, wherein the particle size distribution of the scaly boron nitride filler (B-1) has a particle size (D90) at 90% cumulative particle size of 5.0 to 50.0 μm.

5. A resin composition according to claim 1, wherein the content of the boron nitride filler (B) is 70 parts by mass or more and 250 parts by mass or less per 100 parts by mass of the radical polymerizable compound (A).

6. The resin composition according to claim 1, further comprising a benzoxazine compound (C).

7. The resin composition according to claim 6, wherein the content of the benzoxazine compound (C) is 50 mass% or less based on the total amount of the radical polymerizable compound (A) and the benzoxazine compound (C).

8. A resin composition according to claim 1, further comprising a silica filler (D) in an amount of 50 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the radical polymerizable compound (A).

9. The resin composition according to claim 8, wherein the particle size distribution of the silica filler (D) has a particle size (D50) at 50% cumulative value (D50) of 0.5 to 10.0 μm and a particle size (D90) at 90% cumulative value (D90) of 50.0 μm or less.

10. The resin composition according to claim 1, further comprising a radical polymerizable compound (A-2) different from the maleimide compound (A-1).

11. The dielectric tangent (Df １ 2. The resin composition according to claim 1, wherein the value of (a) is 0.0045 or less.

12. A prepreg comprising the resin composition according to any one of claims 1 to 11 or a semi-cured product of said resin composition and a fibrous base material.

13. A resin-coated film comprising a resin layer containing the resin composition according to any one of claims 1 to 11 or a semi-cured product of said resin composition, and a support film.

14. A resin-coated metal foil comprising a resin layer containing the resin composition according to any one of claims 1 to 11 or a semi-cured product of said resin composition, and a metal foil.

15. A metal-clad laminate comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 11, and a metal foil.

16. A wiring board comprising an insulating layer containing a cured product of the resin composition according to any one of claims 1 to 11, and wiring.

17. A metal-clad laminate comprising an insulating layer containing the cured product of the prepreg according to claim 12 and a metal foil.

18. A wiring board comprising an insulating layer containing the cured product of the prepreg according to claim 12 and wiring.

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