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

Abstract

The present disclosure provides a resin composition with excellent formability and containing an inorganic filler. The resin composition contains a thermosetting resin (A) and an inorganic filler (B). The inorganic filler (B) includes a first filler (B1) and a second filler (B2) of nanometer size, and the particle size of the second filler (B2) is less than the first filler (B1). The first filler (B1) includes anhydrous magnesium carbonate filler (b1) and an alumina filler (b2). Relative to the total solid content in the resin composition, the ratio of the first filler (B1) is 50 volume % to 90 volume %, and the ratio of the second filler (B2) is 0.1 volume % to 2.0 volume %.

Description

Technical Field

[0001] The present disclosure generally relates to a resin composition, a resin film, a metal foil sheet with a resin, a prepreg, a metal-clad laminate, and a printed wiring board. More specifically, the present disclosure relates to a resin composition containing a thermosetting resin, a resin film formed from the resin composition, a metal foil sheet with a resin formed from the resin composition, a prepreg formed from the resin composition, a metal-clad laminate formed from the resin composition, and a printed wiring board formed from the resin composition. Background Art

[0002] Patent document 1 discloses a thermally conductive resin composition. The thermally conductive resin composition includes two or more inorganic fillers (including at least a first inorganic filler and a second inorganic filler), and the total content thereof is equal to or greater than 60 mass % and equal to or less than 95 mass %. The Mohs hardness of the first inorganic filler is greater than 4, and the Mohs hardness of the second inorganic filler is less than 3. In addition, the ratio of the first inorganic filler to the second inorganic filler is equal to or greater than 1:1 and equal to or less than 1:0.01.

[0003] Reference List

[0004] Patent Literature

[0005] Patent Document 1: JP 2012-087250A Summary of the invention

[0006] The problem overcome by the present disclosure is to provide a resin composition having excellent moldability, a resin film formed from the resin composition, a metal foil sheet with resin formed from the resin composition, a prepreg formed from the resin composition, a metal-clad laminate formed from the resin composition, and a printed wiring board formed from the resin composition.

[0007] The resin composition according to one aspect of the present disclosure contains a thermosetting resin (A) and an inorganic filler (B). The inorganic filler (B) includes: a first filler (B1); and a nano-sized second filler (B2) whose particle size is smaller than the first filler (B1). The first filler (B1) includes an anhydrous magnesium carbonate filler (b1) and an aluminum oxide filler (b2). The proportion of the first filler (B1) relative to the total solids in the resin composition is equal to or greater than 50% by volume and equal to or less than 90% by volume. The proportion of the second filler (B2) relative to the total solids in the resin composition is equal to or greater than 0.1% by volume and equal to or less than 2.0% by volume.

[0008] A resin film according to another aspect of the present disclosure contains the above-mentioned resin composition, a dried product of the resin composition, or a semi-cured product of the resin composition.

[0009] A metal foil sheet with resin according to still another aspect of the present disclosure includes: a resin layer containing the above-mentioned resin composition, a dried product of the resin composition, or a semi-cured product of the resin composition; and a metal foil sheet laminated on the resin layer.

[0010] A prepreg according to still another aspect of the present disclosure includes: a base material; and the above-mentioned resin composition, a dried product of the resin composition, or a semi-cured product of the resin composition, any of which is impregnated into the base material.

[0011] A metal-clad laminate according to still another aspect of the present disclosure includes: an insulating layer including an insulating layer of a cured product of the above-mentioned resin composition; and a metal foil sheet laminated on the insulating layer.

[0012] A printed wiring board according to still another aspect of the present disclosure includes: an insulating layer containing a cured product of the above-mentioned resin composition; and a conductor layer laminated on the insulating layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic cross-sectional view of a resin film according to an exemplary embodiment of the present disclosure;

[0014] Figure 2 is a schematic cross-sectional view of a metal foil sheet with resin according to an exemplary embodiment of the present disclosure;

[0015] Figure 3 is a schematic cross-sectional view of a prepreg according to an exemplary embodiment of the present disclosure;

[0016] Figure 4 is a schematic cross-sectional view of a metal-clad laminate according to an exemplary embodiment of the present disclosure;

[0017] Figure 5 A is a schematic cross-sectional view of a printed wiring board according to an exemplary embodiment of the present disclosure; and

[0018] Figure 5 B is a schematic cross-sectional view of a multilayer printed wiring board according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] In the resin composition for forming resin film, metal foil sheet with resin, prepreg, metal-clad laminate and printed wiring board, inorganic filler is used to improve performance such as thermal conductivity and heat resistance. However, inorganic filler tends to cause moldability to decrease. Especially in the case where the resin composition containing inorganic filler is molded to form an insulating layer and the conductor line is embedded in the insulating layer, the resin composition preferably shows good fluidity during its molding process, so that the gap of the conductor line is fully filled by the insulating layer. On the other hand, in order to prevent the resin composition from excessively flowing out during the molding process, it is preferred that the resin composition does not have excessive fluidity. In order to provide appropriate fluidity to such a resin composition, for example, the content of the inorganic filler can be adjusted. However, it is difficult to simply give the resin composition appropriate fluidity by taking such measures alone.

[0020] Therefore, the present inventors conducted intensive research and development to provide a resin composition having excellent moldability and containing an inorganic filler, thereby arriving at the concept of the present disclosure.

[0021] Next, an exemplary embodiment of the present disclosure will be described.

[0022] The resin composition according to an exemplary embodiment contains a thermosetting resin (A) and an inorganic filler (B). The inorganic filler (B) includes: a first filler (B1); and a nano-sized second filler (B2), whose particle size is smaller than the first filler (B1). The first filler (B1) includes an anhydrous magnesium carbonate filler (b1) and an aluminum oxide filler (b2). The ratio of the first filler (B1) to the total solids in the resin composition is equal to or greater than 50 volume % and equal to or less than 90 volume %. The ratio of the second filler (B2) to the total solids in the resin composition is equal to or greater than 0.1 volume % and equal to or less than 2.0 volume %. As used herein, "solids" refers to components in the resin composition except its volatile components such as solvents (i.e., components that will not remain in the cured product).

[0023] A resin film can be formed from the resin composition. A metal foil sheet with a resin can also be formed from the resin composition. A prepreg can also be formed from the resin composition. Each of the resin film, the metal foil sheet with a resin, and the prepreg can also form a metal-clad laminate and a printed wiring board.

[0024] According to the present embodiment, the alumina filler (b2) has a particularly high heat resistance, thereby enabling the cured product of the resin composition to have high heat resistance. In addition, the anhydrous magnesium carbonate filler (b1) has no crystal water and therefore has good heat resistance and is less likely to inhibit the heat resistance of the cured product. In addition, compared with the alumina filler (b2), the anhydrous magnesium carbonate filler (b1) has a lower hardness. Therefore, when the cured product of the resin composition is processed with a drill, the anhydrous magnesium carbonate filler (b1) makes the drill less prone to wear. This makes it easier to impart high heat resistance and drilling processability to the cured product of the resin composition.

[0025] In addition, the second filler (B2) enables the resin combination to show moderate fluidity during the molding process. This makes it easier to fully fill the gap of the conductor line with the insulating layer, particularly when the resin combination is molded to form the insulating layer and the conductor line is embedded in the insulating layer. In addition, this also reduces the excessive flow of the resin combination during the molding process, and can for example reduce the resin combination from the insulating layer to flow out, thereby reducing the possibility of the insulating layer being molded in an unexpected shape.

[0026] Therefore, the present embodiment provides a resin composition having excellent moldability and containing an inorganic filler.

[0027] The present embodiment will be described in more detail.

[0028] First, the respective components of the resin composition will be described.

[0029] The thermosetting resin (A) contains, for example, at least one of a monomer or a prepolymer. The prepolymer may contain an oligomer. The type of polymerization reaction of the thermosetting resin (A) is not limited to any specific type. Specific examples of polymerization reactions include chain polymerization and step-growth polymerization. A typical example of chain polymerization is free radical polymerization. A typical example of step-growth polymerization is addition polymerization.

[0030] The thermosetting resin (A) includes at least one selected from the group consisting of, for example, epoxy resin (a), phenoxy resin, polyimide resin, polyester resin, triazine resin, maleimide resin, polyphenylene ether resin and polyphenylene ether resin having a functional group including a CC unsaturated bond in one molecule, and derivatives of these resins.

[0031] The thermosetting resin (A) preferably comprises at least one of an epoxy resin (a) or a phenoxy resin. The epoxy resin (a) preferably comprises a resin having two or more epoxy rings (oxirane rings) in one molecule. The epoxy resin (a) may be liquid or solid, either of which is suitable.

[0032] The epoxy resin (a) includes at least one selected from the group consisting of: bisphenol epoxy resin; novolac epoxy resin; aryl alkylene epoxy resin; naphthalene skeleton-modified epoxy resin; trifunctional epoxy resin; phenoxy resin; triphenylmethane epoxy resin; anthracene epoxy resin; dicyclopentadiene epoxy resin; norbornene epoxy resin; fluorene epoxy resin; a flame retardant epoxy resin obtained by halogenating any one of the above epoxy resins; an epoxy resin modified with a phosphorus compound; a preliminary reaction product between an epoxy resin and a polyphenylene ether resin; and a preliminary reaction product between an epoxy resin and an acid anhydride; and derivatives of these resins.

[0033] The bisphenol epoxy resin includes at least one selected from the group consisting of: bisphenol A epoxy resin; bisphenol F epoxy resin; and bisphenol S epoxy resin; and derivatives of these resins.

[0034] The novolac epoxy resin includes at least one selected from the group consisting of: a phenol novolac epoxy resin; and a cresol novolac epoxy resin; and derivatives of these resins.

[0035] The aryl alkylene epoxy resin includes at least one selected from the group consisting of: biphenyl epoxy resin; xylylene epoxy resin; phenol aralkyl epoxy resin; biphenyl aralkyl epoxy resin; biphenyl novolac epoxy resin; biphenyl dimethylene epoxy resin; trisphenol methane novolac epoxy resin; and tetramethyl biphenyl epoxy resin; and derivatives of these resins.

[0036] The naphthalene skeleton-modified epoxy resin includes at least one selected from the group consisting of: naphthalene epoxy resin; naphthalene skeleton-modified cresol novolac epoxy resin; naphthalene diol aralkyl epoxy resin; naphthol aralkyl epoxy resin; methoxynaphthalene-modified cresol novolac epoxy resin; and methoxynaphthalene dimethylene epoxy resin; and derivatives of these resins.

[0037] The phenoxy resin is a resin obtained by polymerizing a bisphenol A epoxy resin in a normal chain (or straight chain) form.

[0038] The thermosetting resin (A) preferably includes a liquid resin (eg, an epoxy resin that is in a liquid state at room temperature).

[0039] If the thermosetting resin (A) contains epoxy resin (a), the epoxy resin (a) preferably includes an epoxy resin (a1) having a softening point equal to or lower than 75°C. The ratio of epoxy resin (a1) relative to epoxy resin (a) is preferably equal to or greater than 30% by mass. This enables the sheet to have good flexibility when a sheet-like member (sheet) such as a resin film or a prepreg is formed from the resin composition, and makes it less likely to break even when the sheet is bent. The ratio of epoxy resin (a1) is preferably equal to or greater than 30% by mass, and more preferably equal to or greater than 50% by mass. The ratio of epoxy resin (a1) can even be 100% by mass. In addition, the softening point of epoxy resin (a1) is more preferably equal to or lower than 70°C, and even more preferably equal to or lower than 65°C. The softening point can be measured using a softening point measuring device by a ring and ball method according to JIS K7231 (General Rules for Test Methods of Epoxy Resins and Curing Agents).

[0040] If the thermosetting resin (A) contains at least one of epoxy resin (a) or phenoxy resin, the resin composition preferably also contains a curing agent. The curing agent contains at least one selected from the group consisting of: dicyandiamide; phenolic resin; anhydride; and cyanate ester. Among them, the curing agent preferably contains dicyandiamide. This increases the possibility that the resin film 1 has good flexibility. The phenolic resin may include a phosphorus-containing phenolic resin. This can improve the flame retardancy of the resin composition.

[0041] The resin composition may also contain a catalyst. The catalyst may promote the reaction between the thermosetting resin (A) and the curing agent. The catalyst may include at least one selected from the group consisting of: an organic acid metal salt (such as a metal soap), a tertiary amine, and imidazoles. The organic acid metal salt may include at least one selected from the group consisting of: metal salts of organic acids such as octanoic acid, stearic acid, acetylacetonate, cyclohexane acid, salicylic acid, and octanoic acid, such as Zn salts, Cu salts, and Fe salts. An example of a metal salt of an organic acid may be zinc octanoate (zinc bis(2-ethylhexanoate)). The tertiary amine may include at least one selected from the group consisting of: triethylamine, triethanolamine, and other amines. Imidazoles may include at least one selected from the group consisting of: 2-ethyl-4-methylimidazole, 4-methylimidazole, and other imidazoles.

[0042] As described above, the resin composition contains an inorganic filler (B). The inorganic filler (B) includes: a first filler (B1); and a nano-sized second filler (B2) whose particle size is smaller than that of the first filler (B1). Note that the particle size of the first filler (B1) is a median diameter obtained by a laser diffraction scattering method, while the particle size of the second filler (B2) is a value calculated based on the BET specific surface area of ​​the second filler (B2).

[0043] As described above, the first filler (B1) is equal to or greater than 50% by volume and equal to or less than 90% by volume relative to the total solids, and the second filler (B2) is equal to or greater than 0.1% by volume and equal to or less than 2.0% by volume relative to the total solids. Therefore, the resin composition tends to have good moldability. That is, the ratio of the first filler (B1) is set to more than 50% by volume to improve the thermal conductivity and heat resistance of the resin composition. The ratio of the first filler (B1) is set to less than 90% by volume to reduce the possibility of the insulating layer being molded in an unexpected shape. In addition, the ratio of the second filler (B2) is set to more than 0.1% by volume to give the resin composition moderate fluidity. The ratio of the second filler (B2) is set to less than 2.0% by volume to reduce the possibility of the insulating layer being molded in an unexpected shape.

[0044] The proportion of the first filler (B1) is more preferably equal to or greater than 60% by volume, and even more preferably equal to or greater than 65% by volume. In addition, the proportion of the first filler (B1) is more preferably equal to or less than 87% by volume, and even more preferably equal to or less than 85% by volume. The proportion of the second filler (B2) is more preferably equal to or greater than 0.2% by volume, and even more preferably equal to or greater than 0.3% by volume. In addition, the proportion of the second filler (B2) is more preferably equal to or less than 1.7% by volume, and even more preferably equal to or less than 1.5% by volume.

[0045] In addition, the ratio of the second filler (B2) relative to the solid content other than the inorganic filler (B) is preferably equal to or greater than 1.0 volume % and equal to or less than 8.0 volume %. This makes it even easier to fill the gap of the conductor line with an insulating layer, and further reduces the possibility of the resin composition flowing out from the insulating layer. That is, setting the ratio of the second filler (B2) to more than 1.0 volume % can give the resin composition moderate fluidity, and setting the ratio of the second filler (B2) to less than 8.0 volume % can reduce the possibility of the insulating layer being molded in an unexpected shape. The ratio of the second filler (B2) is more preferably equal to or greater than 1.1 volume %, and even more preferably equal to or greater than 1.2 volume %. The ratio of the second filler (B2) is more preferably equal to or less than 7.0 volume %, and even more preferably equal to or less than 5.0 volume %.

[0046] The first filler (B1) includes, for example, anhydrous magnesium carbonate filler (b1) and aluminum oxide filler (b2). In this case, the anhydrous magnesium carbonate filler (b1) has no crystal water and therefore has high heat resistance. Compared with the anhydrous magnesium carbonate filler (b1), the aluminum oxide filler (b2) has even higher heat resistance. Therefore, if the first filler (B1) includes anhydrous magnesium carbonate filler (b1) and aluminum oxide filler (b2), heat resistance can be imparted to the resin composition.

[0047] Anhydrous magnesium carbonate filler (b1) particles can have, for example, a polyhedral shape, and preferably have a circular shape. Anhydrous magnesium carbonate has no crystal water, and therefore has a thermal stability superior to that of dihydrate, trihydrate or pentahydrate compounds of anhydrous magnesium carbonate. Therefore, if the first filler (B1) includes anhydrous magnesium carbonate filler (b1), the heat resistance of the resin combination can be more easily improved. In order to further improve the heat resistance of the resin combination, the first filler (B1) is preferably free of hydrates of magnesium carbonate, or the hydrates of magnesium carbonate contained in the first filler (B1) are preferably very small amounts of impurities that are inevitably contained.

[0048] Since the anhydrous magnesium carbonate filler (b1) is an inorganic substance, it has a high thermal conductivity. Therefore, the anhydrous magnesium carbonate filler (b1) can improve the thermal conductivity of the resin composition.

[0049] The anhydrous magnesium carbonate filler (b1) is a crystal having a low Mohs hardness, which reduces the wear of the drill when the insulating layer formed of the resin composition is processed with a drill. That is, the anhydrous magnesium carbonate filler (b1) makes it easier to improve the drilling processability of the insulating layer.

[0050] The median diameter (obtained by laser diffraction scattering method) of the anhydrous magnesium carbonate filler (b1) is suitably equal to or greater than 8 μm and equal to or less than 30 μm. Setting the median diameter to more than 8 μm reduces the contact area between the anhydrous magnesium carbonate filler (b1) and the thermosetting resin (A), thereby reducing the possibility of causing the thermal conductivity of the cured product of the resin composition to decrease. Setting the median diameter to less than 30 μm can reduce the possibility of causing the electrical insulation of the cured product of the resin composition to decrease. The median diameter of the anhydrous magnesium carbonate filler (b1) is more preferably equal to or greater than 8 μm and equal to or less than 25 μm, and even more preferably equal to or greater than 8 μm and equal to or less than 20 μm.

[0051] The alumina filler (b2) has higher thermal conductivity and higher heat resistance than the anhydrous magnesium carbonate filler (b1), thereby improving the thermal conductivity and heat resistance of the cured product of the resin composition.

[0052] The shape of the particles forming the alumina filler (b2) is preferably a circular shape. As used herein, "circular shape" refers to a shape without a significantly protruding part. The circular shape includes, for example, a spherical shape and an ellipsoidal shape, but does not include a plate shape, a polyhedral shape, a cuboid shape, a rod shape, a needle shape or a scale shape. Making the particles forming the alumina filler (b2) circular is easier to improve the fluidity of the resin composition during the molding process, thereby making it easier to improve the moldability of the resin composition.

[0053] The alumina filler (b2) has a high Mohs hardness and therefore preferably has a median diameter as small as possible. Specifically, the median diameter of the alumina filler (b2) is preferably equal to or greater than 0.1 μm and equal to or less than 5 μm. This can reduce the wear of the drill when the cured product of the resin composition is processed with a drill. The median diameter of the alumina filler (b2) is more preferably equal to or greater than 0.1 μm and equal to or less than 4.0 μm, and even more preferably equal to or greater than 0.1 μm and equal to or less than 3.0 μm.

[0054] The ratio of anhydrous magnesium carbonate filler (b1) relative to inorganic filler (B) is preferably equal to or greater than 25 volume % and equal to or less than 75 volume %. If the ratio of anhydrous magnesium carbonate filler (b1) is less than 35 volume %, the ratio of alumina filler (b2) is relatively increased. Alumina filler (b2) has high hardness. Therefore, as the ratio of alumina filler (b2) increases, drilling processability tends to be more easily reduced. If the ratio of anhydrous magnesium carbonate filler (b1) is greater than 65 volume %, the ratio of alumina filler (b2) is relatively reduced. In the case where anhydrous magnesium carbonate filler (b1) (particles) has a non-circular shape (such as a polyhedral shape), as the content of anhydrous magnesium carbonate filler (b1) increases, even if alumina filler (b2) (particles) has a circular shape, the moldability of the resin composition is more easily reduced. The ratio of anhydrous magnesium carbonate filler (b1) is more preferably equal to or greater than 30 volume % and equal to or less than 70 volume %, and even more preferably equal to or greater than 35 volume % and equal to or less than 65 volume %.

[0055] In addition, the proportion of the alumina filler (b2) relative to the inorganic filler (B) is preferably equal to or greater than 25 volume % and equal to or less than 75 volume %, more preferably equal to or greater than 30 volume % and equal to or less than 70 volume %, and even more preferably equal to or greater than 35 volume % and equal to or less than 65 volume %.

[0056] The median diameter of the anhydrous magnesium carbonate filler (b1) is preferably greater than the median diameter of the alumina filler (b2). This makes it easier to densely fill the resin composition and its cured product with the first filler (B1). This will form the particles of the anhydrous magnesium carbonate filler (b1) and the alumina filler (b2) close to each other, so that it is easier to form a heat conduction path, and thus improve the thermal conductivity of the resin composition and its cured product. Among them, it is particularly recommended that the median diameter of the anhydrous magnesium carbonate filler (b1) is equal to or greater than 8μm and equal to or less than 30μm, and the median diameter of the alumina filler (b2) is less than 5μm. This will further improve their thermal conductivity.

[0057] Optionally, the first filler (B1) may contain additional components except anhydrous magnesium carbonate filler (b1) and alumina filler (b2). For example, the first filler (B1) may also include an inorganic filler (b3) loaded with a molybdenum compound thereon. Each particle of the inorganic filler (b3) may have a core of, for example, an inorganic substance and a molybdenum compound loaded on the core. For example, in each particle of the inorganic filler (b3), the surface of the core may be partially or completely covered by a molybdenum compound.

[0058] The inorganic material contained in the inorganic filler (b3) is not limited to any specific inorganic material. The inorganic material includes at least one selected from the group consisting of carbonate, metal oxide, silicate, metal hydroxide and other compounds. Examples of carbonates include calcium carbonate. Examples of metal oxides include zinc oxide. Examples of silicates include talc. Examples of metal hydroxides include magnesium hydroxide.

[0059] The molybdenum compound is not limited to any specific molybdenum compound. The molybdenum compound contains at least one selected from the group consisting of zinc molybdate; calcium molybdate; magnesium molybdate; molybdenum trioxide; aluminum molybdate; barium molybdate; sodium molybdate; potassium molybdate; phosphomolybdic acid; ammonium phosphomolybdate; sodium phosphomolybdic acid; silicomolybdic acid; molybdenum boride; molybdenum disilicide; molybdenum nitride; and molybdenum carbide. Among them, from the viewpoint of chemical stability, moisture resistance and insulation, the molybdenum compound preferably contains at least one selected from the group consisting of zinc molybdate, calcium molybdate and magnesium molybdate.

[0060] If the first filler (B1) includes an inorganic filler (b3), the drilling processability of the cured product of the resin composition can be more easily improved because the molybdenum compound is supported on the inorganic core in the inorganic filler (b3). Among them, if the core in the inorganic filler (b3) is talc, it is even easier to improve the drilling processability.

[0061] If the first filler (B1) further comprises an inorganic filler (b3), the ratio of the inorganic filler (b3) relative to the inorganic filler (B) is preferably 10% by volume or less. The heat resistance of the inorganic filler (b3) may be lower than the heat resistance of the anhydrous magnesium carbonate filler (b1) or the heat resistance of the alumina filler (b2). Therefore, setting the ratio of the inorganic filler (b3) to 10% by volume or less enables the heat resistance of the resin composition to be suppressed from decreasing.

[0062] The first filler (B1) is preferably surface treated with a coupling agent. This improves the adhesion between the thermosetting resin (A) and the first filler (B1). The surface treatment method can be a wet treatment or a dry treatment, whichever is suitable. At least one of the anhydrous magnesium carbonate filler (b1) or the aluminum oxide filler (b2) is preferably surface treated with a coupling agent.

[0063] Any coupling agent can be used without limitation, as long as the coupling agent includes a reactive group chemically bonded to an inorganic material and a reactive group chemically bonded to an organic material in one molecule. Specific examples of the reactive group chemically bonded to an inorganic material include an ethoxy group and a methoxy group. Specific examples of the reactive group chemically bonded to an organic material include an epoxy group, an amino group, an isocyanate group, a hydroxyl group, a phenolic hydroxyl group, and an anhydride group.

[0064] The coupling agent includes a silane coupling agent. The silane coupling agent may include, for example, epoxy silane, amino silane, isocyanate silane and anhydride silane. Specific examples of epoxy silane include 3-glycidyloxypropyl trimethoxy silane and 3-glycidyloxypropyl triethoxy silane. Specific examples of amino silane include 3-aminopropyl triethoxy silane. Specific examples of isocyanate silane include 3-isocyanate propyl triethoxy silane.

[0065] On the other hand, as described above, the particle size of the second filler (B2) is nanometer-sized and smaller than the particle size of the first filler (B1). This is why the second filler (B2) has a larger specific surface area compared to the first filler (B1), thereby enabling the resin composition to have moderate fluidity. The particle size of the second filler (B2) is preferably less than 100 nm, and more preferably equal to or less than 50 nm. This enables even a smaller amount of the second filler (B2) to impart moderate fluidity to the resin composition. In addition, the specific surface area (measured by the BET method) of the second filler (B2) is preferably equal to or greater than 100 m 2 / g and equal to or less than 400m 2 / g. The specific surface area is set to 100m 2 / g or more can give the resin composition appropriate fluidity. The specific surface area is set to 400m 2 / g or less can reduce the possibility of the insulating layer being formed into an unexpected shape. The specific surface area is more preferably equal to or greater than 130m 2 / g and equal to or less than 350m 2 / g, and even more preferably equal to or greater than 150m 2 / g and equal to or less than 300m 2 / g.

[0066] The material of the second filler (B2) is not limited to any specific material. The second filler (B2) preferably comprises at least one of silicon dioxide or aluminum oxide. The silicon dioxide comprises at least one of dry silicon dioxide such as fumed silicon dioxide or wet silicon dioxide prepared by a wet process such as a solvent-gel process. The aluminum oxide comprises dry aluminum oxide such as fumed aluminum oxide.

[0067] The second filler (B2) is preferably subjected to a hydrophobic treatment. In particular, the second filler (B2) is preferably treated with at least one surface treatment agent selected from the group consisting of: alkylsilane, silicone oil, epoxysilane, aminosilane, isocyanate silane and anhydride silane. This enables the second filler (B2) with a small particle size to be fully dispersed in the resin composition, and is therefore less likely to inhibit the fluidity of the resin composition.

[0068] The resin composition may also contain additives other than the above components. The additive includes at least one selected from the group consisting of the following: a flame retardant, a coupling agent, and a dispersant. The flame retardant may be an organic flame retardant or an inorganic flame retardant, either of which is suitable. The organic flame retardant includes at least one selected from the group consisting of the following: a halogen compound, a phosphorus compound, and other compounds. The phosphorus compound includes at least one selected from the group consisting of the following: a phosphate flame retardant; a phosphazene flame retardant; a bisdiphenylphosphine oxide flame retardant; and a hypophosphite flame retardant. The phosphate flame retardant includes, for example, a condensed phosphate ester of di(xylyl) phosphate. The phosphazene flame retardant includes, for example, phenoxyphosphazene. The bisdiphenylphosphine oxide flame retardant includes, for example, dimethylbenzene bisdiphenylphosphine oxide. The hypophosphite flame retardant includes, for example, a hypophosphite metal salt of a dialkyl aluminum hypophosphite. The inorganic flame retardant includes, for example, a metal hydroxide.

[0069] Any coupling agent can be used without limitation, as long as the coupling agent includes a reactive group chemically bonded to an inorganic material and a reactive group chemically bonded to an organic material in one molecule. Specific examples of reactive groups chemically bonded to inorganic materials include ethoxy and methoxy groups. Specific examples of reactive groups chemically bonded to organic materials include epoxy, amino, isocyanate, hydroxyl, phenolic hydroxyl and anhydride groups. Coupling agents include silane coupling agents. Silane coupling agents may include, for example, epoxy silanes, amino silanes, isocyanate silanes and anhydride silanes. Specific examples of epoxy silanes include 3-glycidyloxypropyl trimethoxy silane and 3-glycidyloxypropyl triethoxy silane. Specific examples of amino silanes include 3-aminopropyl triethoxy silane. Specific examples of isocyanate silanes include 3-isocyanate propyl triethoxy silane. Further adding a coupling agent to the resin composition improves the adhesion between the organic material and the inorganic material.

[0070] The dispersant is a surfactant, and is not limited to any specific dispersant. Further adding the dispersant to the resin composition enables the first filler (B1) and the second filler (B2) to be more uniformly dispersed.

[0071] For example, the resin composition can be prepared by mixing the above components together. If the thermosetting resin (A) is in a solid state at room temperature, a solvent is suitably further added to the resin composition. Any solvent can be used without restriction, as long as the solvent can at least dissolve the thermosetting resin (A). For example, methyl ethyl ketone can be used as a solvent. However, if the thermosetting resin (A) is in a liquid state at room temperature, it is not necessary to further add any solvent to the resin composition.

[0072] The resin film 1 according to the present embodiment comprises a resin composition, a dried product of the resin composition or a semi-cured product of the resin composition. The resin film 1 can be formed by applying the resin composition to a support film and then heating the resin composition. The resin film 1 is used in the case of peeling off its support film. The support film can be, for example, a polyethylene terephthalate (PET) film.

[0073] For example, the insulating layer 40 of the metal-clad laminate 4 and the insulating layer 50 of the printed wiring board 5 can be formed by curing the resin film 1 .

[0074] For example, the thickness of the resin film 1 may be, but is not necessarily, equal to or greater than 50 μm and equal to or less than 200 μm.

[0075] The metal foil sheet 2 with resin according to the present embodiment includes a resin layer 20 and a metal foil sheet 21 laminated on the resin layer 20. The resin layer 20 contains a resin composition, a dried product of the resin composition, or a semi-cured product of the resin composition.

[0076] The metal foil sheet 2 with resin can be manufactured by applying the resin composition onto the metal foil sheet 21 and then heating the resin composition to form the resin layer 20 .

[0077] For example, the insulating layer 40 of the metal-clad laminate 4 and the insulating layer 50 of the printed wiring board 5 can be formed by curing the resin layer 20 of the metal foil sheet 2 with resin.

[0078] The prepreg 3 according to the present embodiment includes: a base material; and a resin composition, a dried product of the resin composition, or a semi-cured product of the resin composition, any of which is impregnated into the base material.

[0079] The prepreg 3 can be formed by, for example, impregnating a base material 31 with a resin composition and then heating the resin composition. The base material 31 can be, for example, a glass cloth sheet.

[0080] For example, the insulating layer 40 of the metal-clad laminate 4 and the insulating layer 50 of the printed wiring board 5 may be formed by curing the prepreg 3 .

[0081] like Figure 4 As shown, the metal-clad laminate 4 according to the present embodiment includes an insulating layer 40 and a metal foil sheet 41. The insulating layer 40 includes a cured product of a resin composition. The metal foil sheet 41 is bonded to the insulating layer 40.

[0082] The metal foil sheet 41 may be, for example, a copper foil sheet. The thickness of the metal foil sheet 41 is not limited to any specific value, but is preferably equal to or greater than 12 μm and equal to or less than 420 μm, and more preferably equal to or greater than 18 μm and equal to or less than 210 μm. The ten-point average roughness Rzjis of the metal foil sheet 41 is not limited to any specific value, but is preferably 3 μm or more, and more preferably 5 μm or more. Setting the ten-point average roughness Rzjis of the metal foil sheet 41 to 3 μm or more more significantly improves the adhesion between the insulating layer 40 and the metal foil sheet 41.

[0083] For example, the metal-clad laminate 4 can be formed, for example, by stacking at least one metal foil sheet 41 on any one surface or both surfaces of a single prepreg 3 or a multilayer laminate of more than two prepregs 3, and hot pressing the multilayer laminate. Before the metal foil sheet 41 is stacked on the prepreg 3, the surface of the metal foil sheet 41 (at least the surface to be stacked on the prepreg 3) is treated with a coupling agent. Surface treatment of the metal foil sheet 41 with a coupling agent in this way enables the coupling agent to couple the organic material in the prepreg 3 with the metal foil sheet 41, thereby further improving the adhesion between the insulating layer 40 and the metal foil sheet 41. Any of the above-mentioned exemplary coupling agents can be used as a coupling agent. The conditions for hot pressing are not limited to any specific conditions. Figure 4 A metal-clad laminate 4 is shown in which two substrates 31 are embedded in an insulating layer 40. In this embodiment, the resin composition has moderate fluidity. This reduces the possibility of the resin composition, the dried product of the resin composition, or the semi-cured product of the resin composition flowing out from the prepreg formed by the resin composition when the multilayer laminate is hot-pressed. This reduces the possibility of causing molding failure.

[0084] like Figure 5 As shown in Figures 5A and 5B, the printed wiring board 5 according to the present embodiment includes an insulating layer 50 and a conductor layer 51. The insulating layer 50 contains a cured product of a resin composition. The conductor layer 51 is combined with the insulating layer 50. As used herein, the conductor layer 51 refers to a layer having conductivity, such as a signal layer, a power layer, and a ground layer. Each conductor layer 51 can be a conductor line or a metal foil sheet without a pattern. Note that the printed wiring board 5 is a concept covering a multilayer printed wiring board having three or more conductor layers 51. Specifically, Figure 5 B shows a multilayer printed wiring board 5 including three conductor layers 51 .

[0085] The printed wiring board 5 may be formed, for example, by applying a subtractive method to the metal-clad laminate 4 as a material. Optionally, the printed wiring boards 5 may be stacked on each other by a buildup method.

[0086] Specifically, Figure 5 The printed wiring board 5 shown in A can be manufactured by forming a conductor line as a conductor layer 51 from the metal foil sheet 41 of the metal-clad laminate 4 by a subtractive method, for example. Optionally, a hole passing through the metal-clad laminate 4 can be opened by processing the metal-clad laminate 4 with a drill, and a through-hole metal can be formed by plating the inner surface of the hole while forming the conductor line. That is, a printed wiring board 5 having such a through-hole metal can be formed. According to the present embodiment, this makes the drill less prone to wear.

[0087] Alternatively, the printed wiring board 5 can also be manufactured in the following manner. First, the core material 6 is formed by forming a conductor line as the conductor layer 51 from the metal foil sheet 41 of the metal-clad laminate 4 by, for example, a subtractive method. Figure 5The printed wiring board 5 shown in A is used as the core material 6. Next, the core material 6 and the metal foil sheet 2 with resin are stacked on each other so that the resin layer 20 of the metal foil sheet 2 with resin is superimposed on a conductor line of the core material 6. In this state, the core material 6 and the metal foil sheet 2 with resin are hot pressed. In this embodiment, the resin composition has moderate fluidity. This reduces the possibility that the resin composition, the dried product of the resin composition, or the semi-cured product of the resin composition flows out of the resin layer 20 formed by the resin composition at this time. In addition, this is conducive to the resin layer 20 flowing into the gap of the conductor line. The insulating layer 22 is formed by curing this resin layer 20. At this time, the gap of the conductor line is easily filled with the insulating layer 22. Subsequently, the conductor line as the conductor layer 51 can be formed by, for example, a subtractive method from the metal foil sheet 21 derived from the metal foil sheet 2 with resin. In this way, a structure such as Figure 5 B shows a multilayer printed wiring board 5. This multilayer printed wiring board 5 includes an insulating layer 40 derived from a core material 6 and another insulating layer 22 formed of a resin layer 20 of a metal foil sheet 2 with a resin, as an insulating layer 50. Optionally, a printed wiring board 5 with an even greater number of layers can also be manufactured by using this multilayer printed wiring board 5 as a core material and using a metal foil sheet 2 with a resin in the same manner as described above. A hole through this printed wiring board 5 can be opened by processing the printed wiring board 5 with a drill, and a through-hole metal can be formed by plating the inner surface of the hole. According to the present embodiment, this makes the drill less susceptible to wear.

[0088] Still alternatively, the printed wiring board 5 can also be manufactured in the following manner. The core material 6, the resin film 1 and the metal foil sheet are stacked on each other so that the resin film 1 is stacked on the conductor line of the core material 6, and the metal foil sheet is stacked on the resin film 1. In this state, the core material 6, the resin film 1 and the metal foil sheet are hot pressed. In the present embodiment, the resin composition has moderate fluidity. This reduces the possibility that the resin composition, the dried product of the resin composition or the semi-cured product of the resin composition flows out from the resin film 1 formed by the resin composition at this time. In addition, this is conducive to the resin film 1 flowing into the gap of the conductor line. The insulating layer is formed by curing this resin film 1. At this time, the gap of the conductor line is easy to be fully filled with the insulating layer. Subsequently, the conductor line can be formed by the metal foil sheet by, for example, a subtractive method. In this way, a multilayer printed wiring board 5 can be formed. Optionally, a printed wiring board 5 with an even larger number of layers can also be manufactured by using this multilayer printed wiring board 5 as a core material and using a metal foil sheet with resin in the same manner as described above. A hole can be opened through the printed wiring board 5 by processing the printed wiring board 5 with a drill, and a through-hole metal can be formed by plating the inner surface of the hole. According to the present embodiment, this makes the drill less susceptible to wear.

[0089] In the foregoing description, the core material 6 is formed by the metal-clad laminate 4 including the insulating layer 40 formed from the resin composition according to the present embodiment, and then the printed wiring board 5 is formed from the core material 6. However, the core material 6 is not necessarily formed as described above. That is, the insulating layer 40 of the core material 6 is not necessarily formed from the resin composition according to the present embodiment.

[0090] Example

[0091] Next, specific examples of the present embodiment will be provided. Note that these are merely examples of the present embodiment and should not be construed as limiting.

[0092] 1. Materials

[0093] Provide the following materials:

[0094] Epoxy resin 1: naphthalene liquid epoxy resin; product number HP-4032D, manufactured by DIC Corporation; specific gravity 1.20; liquid at room temperature;

[0095] Epoxy resin 2: naphthalene epoxy resin; product number HP-4710, manufactured by DIC Corporation; specific gravity of 1.20, and softening point of 95° C.;

[0096] Epoxy resin 3: bisphenol A epoxy resin; product name EPICLON 850-S, manufactured by DIC Corporation; specific gravity 1.15; liquid at room temperature;

[0097] Epoxy resin 4: trifunctional epoxy resin; product number VG-3101, manufactured by Printec Inc.; specific gravity of 1.18, and softening point of 61° C.;

[0098] Phenoxy resin: Product No. YP-50, manufactured by Nippon Steel Chemical & Materials Co., Ltd.;

[0099] Polyphenylene ether resin: Product number SA-90, manufactured by SABIC Japan llc;

[0100] Phenolic resin 1: phosphorus-containing phenolic resin; product number XZ92741, manufactured by Dow Chemical Company;

[0101] Phenolic resin 2: product number MEH-7600-4H, manufactured by Meiwa Plastic Industries, Ltd.;

[0102] Curing agent: dicyandiamide;

[0103] Catalyst: 2-ethyl-4-methylimidazole;

[0104] Flame retardant: phosphate ester; product number PX-200, manufactured by Daihachi Chemical Industry Co., Ltd.; specific gravity: 1.26;

[0105] Coupling agent: silane coupling agent; product number KBE-403, manufactured by Shin-Etsu Chemical Co., Ltd.; specific gravity 1.00;

[0106] Dispersant: Wetting dispersant; product number BYK-W903, manufactured by BYK Japan KK; specific gravity 1.00;

[0107] Leveling agent: Product No. F-556, manufactured by DIC Corporation; specific gravity 1.00;

[0108] Anhydrous magnesium carbonate filler: synthetic magnesite; product number MS-PS, manufactured by Konoshima Chemical Co., Ltd.; median diameter of 12 μm, and specific gravity of 3.04;

[0109] Alumina filler: spherical alumina; product number AO-502, manufactured by Admatechs; median diameter 0.25 μm, and specific gravity 3.96;

[0110] Calcium carbonate having calcium molybdate supported thereon; product number KG-501, manufactured by Huber Inc.; median diameter 4.5 μm, and specific gravity 3.00;

[0111] Dry silica 1: fumed silica; product name AEROSIL R972, manufactured by Evonik Japan Co., Ltd.; BET specific surface area of ​​110 m 2 / g, and the specific gravity is 2.20;

[0112] Dry silica 2: fumed silica; product name AEROSIL R974, manufactured by Evonik Japan Co., Ltd.; BET specific surface area of ​​170 m 2 / g, and the specific gravity is 2.20;

[0113] Dry silica 3: fumed silica; product name AEROSIL R976S, manufactured by Evonik Japan Co., Ltd.; BET specific surface area of ​​240 m 2 / g, and the specific gravity is 2.20;

[0114] Dry silica 4: fumed silica; product name AEROSIL RX200R, manufactured by Evonik Japan Co., Ltd.; BET specific surface area: 140 m 2 / g, and the specific gravity is 2.20;

[0115] Dry silica 5: fumed silica; product name AEROSIL RX300, manufactured by Evonik Japan Co., Ltd.; BET specific surface area: 210 m 2 / g, and the specific gravity is 2.20;

[0116] Dry silica 6: fumed silica; product name AEROSIL R805, manufactured by Evonik Japan Co., Ltd.; BET specific surface area of ​​150 m 2 / g, and the specific gravity is 2.20;

[0117] Dry alumina: pyrogenic alumina; product name AEROXIDE Alu C805, manufactured by Evonik Japan Co., Ltd.; BET specific surface area of ​​90 m 2 / g, and the specific gravity is 3.96;

[0118] Wet silica 1: methyl ethyl ketone dispersed silica sol; product number MEK-EC-2130Y, manufactured by Nissan Chemical Corporation; BET specific surface area of ​​230 m 2 / g, and a specific gravity of 2.20; and

[0119] Wet silica 2: methyl ethyl ketone dispersed silica sol; product number MEK-EC-2430Z, manufactured by Nissan Chemical Corporation; BET specific surface area of ​​230 m 2 / g, and the specific gravity is 2.20.

[0120] Each of dry silica, dry alumina, and wet silica is surface treated with at least one surface treatment agent selected from the group consisting of the following: alkylsilane, silicone oil, and epoxysilane. As a surface treatment method, in the case of dry fillers (i.e., in the case of dry silica and dry alumina), a method of hydrophobizing the filler using an organic halogen silane in a fluidized bed or a method of hydrophobizing an organopolysiloxane using an alkaline catalyst. In the case of wet silica, a method of hydrophobizing silica in the following manner is performed: a mixture containing a silanizing agent, a hydrophobic organic solvent, an alcohol, and water is added to a hydrophilic colloidal silica, and in the case of removing the alkali or neutralizing the alkali with an acid of an equal amount or more, the mixture is ripened at a temperature of 0°C to 100°C together with silica.

[0121] 2. Preparation of the composition

[0122] After the above materials were mixed together to obtain any one of the compositions shown in Tables 1 to 3, methyl ethyl ketone and dimethylformamide were added to the mixture so that the solid concentration was equal to or greater than 80% by mass and equal to or less than 95% by mass. Then, the mixture was stirred with a planetary mixer. In this way, a composition was prepared.

[0123] 3. Preparation of resin film

[0124] A resin film having a thickness of 100 μm was prepared by coating the composition on a polyethylene terephthalate film and then semi-curing the resin composition by heating the composition at about 150° C. for 3 to 5 minutes.

[0125] 4. Evaluation test

[0126] (1) Film properties

[0127] The appearance of the resin film was examined in the case where the resin film was wound around a SUS rod having a diameter of 10 mm and in the case where the resin film was wound around a SUS rod having a diameter of 100 mm.

[0128] If cracks were not recognized on any of the resin films wound on the rods, the resin film was rated as "A". If cracks were recognized only on the resin film wound on the SUS rod having a diameter of 10 mm, the resin film was rated as "B". If cracks were recognized on all of the resin films wound on the rods, the resin film was rated as "C".

[0129] (2) Resin fluidity

[0130] The resin film was cut into a size of 100 mm×100 mm in plan view to prepare a test sample. Two of these samples were laminated to each other, and the weight thereof was measured.

[0131] A pair of demoulding polyethylene terephthalate films are arranged so that their demoulding surfaces face each other, and the laminate of two samples is placed between the pair of demoulding polyethylene terephthalate films. In this state, the laminate of the sample is hot pressed together with the polyethylene terephthalate film under conditions (condition 1) including 130°C, 5 minutes and 0.5MPa, thereby forming a cured product by the laminate of the sample. The cured product is punched out with a die head to form a treated sample with a diameter of 80mmΦ in a plan view, and its weight is measured. Based on the weight M0 of the sample and the weight M of the treated sample, the fluidity of the resin is calculated by the following formula:

[0132] Resin fluidity (%) = (M0-2M) / M0×100

[0133] The resin fluidity was also calculated in the same manner in the case where hot pressing was performed under conditions including 130° C., 5 minutes, and 2.0 MPa (Condition 2).

[0134] If the resin fluidity is equal to or less than 30% under condition 1 and greater than 45% under condition 2, the sample is rated as "A". If the resin fluidity is greater than 30% under condition 1 and greater than 45% under condition 2, the sample is rated as "B". If the resin fluidity is equal to or less than 30% under condition 1 and equal to or less than 45% under condition 2, the sample is rated as "C".

[0135] (3) Filling

[0136] A double-sided copper-clad laminate (product number R-1566, manufactured by Panasonic Corporation; copper foil thickness of 35 μm) was provided. The copper foil of this double-sided copper-clad laminate was etched to form a grid of conductor lines, thereby obtaining a printed wiring board for testing. A resin film was laminated on each of the two conductor lines of the printed wiring board and heated to 200° C., 2.94 MPa (=30 kgf / cm 2 The multilayer laminate was formed by hot pressing under the conditions of 20% to 60 minutes. In each of the three cases where the residual copper ratio of the conductor line was 20%, 50% and 80%, respectively, the test was carried out in the same manner.

[0137] The insulating layer formed of the resin film of the multilayer laminate was inspected with the naked eye to see whether the insulating layer had any pores inside. If no pores were identified in the insulating layer, the multilayer laminate was rated "A". If any pores were identified therein, the multilayer laminate was rated "B".

[0138] (4) Thermal conductivity

[0139] Eight resin films each having a thickness of 100 μm were stacked one on top of the other, and the stack of these resin films was sandwiched between the roughened surfaces of two copper foil sheets (each having a thickness of 35 μm). The multilayer stack thus obtained was heated at 195° C. and 2.94 MPa (=30 kgf / cm 2 ) for 60 minutes, thereby manufacturing a copper clad laminate (CCL) whose total insulating layer thickness is 800 μm.

[0140] The copper foil sheet was etched away from the copper-clad laminate to obtain a resin board. The thermal diffusivity α of the resin board was estimated by the laser flash method, its specific heat Cp was estimated by the DSC method, and its specific gravity ρ was estimated by collecting gas above water. Based on these results, the thermal conductivity λ was calculated by the following formula:

[0141] λ(W / m·K)=α(m 2 / s)×Cp(J / kg·K)×p(kg / m 3 )

[0142] The results of these tests are summarized in Tables 1-4 below:

[0143] [Table 1]

[0144]

[0145] [Table 2]

[0146]

[0147] [Table 3]

[0148]

[0149] [Table 4]

[0150]

[0151] Reference numerals list

[0152] 1. Resin film

[0153] 2Metal foil sheet with resin

[0154] 20 resin layers

[0155] 21 Metal foil sheet

[0156] 3 Prepreg

[0157] 31 Base material

[0158] 4 Metal-clad laminate

[0159] 40 insulation layer

[0160] 41 Metal foil sheet

[0161] 5. Printed Circuit Board

[0162] 50 insulation layer

[0163] 51 conductor layer

Claims

1. A resin composition comprising a thermosetting resin (A) and an inorganic filler (B), The inorganic filler (B) comprises: a first filler (B1); and a nano-sized second filler (B2) having a smaller particle size than the first filler (B1), The first filler (B1) includes an anhydrous magnesium carbonate filler (b1), an alumina filler (b2) and an inorganic filler (b3) on which a molybdenum compound is loaded, The ratio of the first filler (B1) to the total solid content in the resin composition is equal to or greater than 50 volume % and equal to or less than 90 volume %, The ratio of the second filler (B2) to the total solid content in the resin composition is equal to or greater than 0.1 volume % and equal to or less than 2.0 volume %, The ratio of the alumina filler (b2) to the inorganic filler (B) is equal to or greater than 25 volume % and equal to or less than 75 volume %.

2. The resin composition according to claim 1, wherein The ratio of the second filler (B2) to the solid content excluding the inorganic filler (B) is equal to or greater than 1.0 volume % and equal to or less than 8.0 volume %.

3. The resin composition according to claim 1 or 2, wherein The ratio of the anhydrous magnesium carbonate filler (b1) to the inorganic filler (B) is equal to or greater than 25 volume % and equal to or less than 75 volume %.

4. The resin composition according to claim 1 or 2, wherein The anhydrous magnesium carbonate filler (b1) has a median diameter of 8 μm or more and 30 μm or less when measured by a laser diffraction scattering method, and The alumina filler (b2) has a median diameter of 0.1 μm or more and 5 μm or less when measured by a laser diffraction scattering method.

5. The resin composition according to claim 1 or 2, wherein The specific surface area of ​​the second filler (B2) is equal to or greater than 100 m 2 / g and equal to or less than 400m 2 / g.

6. The resin composition according to claim 1 or 2, wherein The second filler (B2) is treated with at least one surface treatment agent selected from the group consisting of alkylsilane, silicone oil, epoxysilane, aminosilane, isocyanatesilane and anhydridesilane.

7. The resin composition according to claim 1 or 2, wherein The thermosetting resin (A) contains an epoxy resin (a), and The epoxy resin (a) includes an epoxy resin (a1) having a softening point of 75° C. or less, and a ratio of the epoxy resin (a1) relative to the epoxy resin (a) is equal to or greater than 30% by mass. 8 . A resin film comprising the resin composition according to claim 1 , a dried product of the resin composition, or a semi-cured product of the resin composition.

9. A metal foil sheet with resin, comprising: A resin layer, the resin layer comprising the resin composition according to any one of claims 1 to 7, a dried product of the resin composition, or a semi-cured product of the resin composition; and A metal foil sheet is laminated on the resin layer.

10. A prepreg, comprising: substrate; and The resin composition according to any one of claims 1 to 7, a dried product of the resin composition, or a semi-cured product of the resin composition, any of which is impregnated into the substrate.

11. A metal-clad laminate, comprising: An insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 7; and A metal foil sheet is laminated on the insulating layer.

12. A printed circuit board, comprising: An insulating layer comprising a cured product of the resin composition according to any one of claims 1 to 7; and A conductor layer is stacked on the insulating layer.

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