Resin composition, varnish, film, laminate and metal-clad laminate

Abstract

To provide a resin composition and a varnish which are capable of giving a film, a laminate and a metal-clad laminate improved in performance balance of low dielectric characteristics, low thermal expansion and thermal conductivity, and to provide a film, a laminate and a metal-clad laminate improved in performance balance of low dielectric characteristics, low thermal expansion and thermal conductivity.SOLUTION: The resin composition contains a thermosetting cyclic olefinic copolymer (A) having a crosslinkable group, a radical polymerization initiator (B), an antioxidant (C), and an inorganic filler (D). The inorganic filler (D) contains a plate-like inorganic filler (D1) having an average aspect ratio of 2 or more and 170 or less. The content of the inorganic filler (D1) is 30 pts.mass or more and 300 pts.mass or less based on 100 pts.mass of the thermosetting cyclic olefinic copolymer (A).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition, a varnish, a film, a laminate, and a metal clad laminate. [Background technology]

[0002] Metal clad laminates used as intermediate substrates for high frequency printed wiring boards and the like are composed of a laminated structure in which a metal foil is laminated to the surface of a composite plate of resin and glass cloth. The resin used in the metal clad laminate is required to have basic properties such as insulation and low thermal expansion. An example of a technology for such a metal clad laminate is described in Patent Document 1.

[0003] Patent Document 1 describes a resin composition that contains a polyphenylene ether compound, a curing agent capable of reacting with the polyphenylene ether compound, and an inorganic filler including a boron nitride filler, with the aim of providing a resin composition that can give a cured product having low dielectric properties, high thermal conductivity, and excellent peel strength, and in which the particle size distribution of the inorganic filler, as measured by a laser diffraction particle size distribution measurement method, has at least two peaks in a particle size distribution range of 0.8 to 30.0 μm, with at least one peak in a particle size range of 0.8 to 5.0 μm and at least one peak in a particle size range of 5.0 to 30.0 μm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 014584 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it has become clear that there is room for improvement in the resin used in the metal clad laminate with respect to the balance of performance between low dielectric properties, low thermal expansion properties, and thermal conductivity. In view of the above circumstances, the present invention provides a resin composition and varnish that can provide a film, laminate, and metal-clad laminate having an improved performance balance of low dielectric properties, low thermal expansion, and thermal conductivity, as well as a film, laminate, and metal-clad laminate having an improved performance balance of low dielectric properties, low thermal expansion, and thermal conductivity. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems, and have found that by using a thermosetting cyclic olefin copolymer having a crosslinkable group in a resin composition, and by using an inorganic filler having an average aspect ratio within a predetermined range and by controlling the content of the inorganic filler within a predetermined range, the performance balance of low dielectric properties, low thermal expansion properties, and thermal conductivity of the resulting film, laminate, and metal-clad laminate can be improved, and the present invention has been completed. According to the present invention, there are provided a resin composition, a varnish, a film, a laminate, and a metal clad laminate as shown below.

[0007] [1] A resin composition comprising a thermosetting cyclic olefin copolymer (A) having a crosslinkable group, a radical polymerization initiator (B), an antioxidant (C), and an inorganic filler (D), The inorganic filler (D) contains a plate-like inorganic filler (D1) having an average aspect ratio of 2 or more and 170 or less, A resin composition, wherein the content of the inorganic filler (D1) is 30 parts by mass or more and 300 parts by mass or less based on 100 parts by mass of the thermosetting cyclic olefin copolymer (A). [2] The inorganic filler (D1) has a volume resistivity of 1.0×10 8 The resin composition according to [1], having a resistivity of Ω·cm or more. [3] The volume-based average particle size D of the inorganic filler (D1) measured by a laser diffraction particle size distribution measurement method 50 The resin composition according to [1] or [2], wherein the particle size is 0.1 μm or more and 30.0 μm or less. [4] The resin composition according to any one of [1] to [3], wherein the inorganic filler (D1) comprises at least one selected from the group consisting of boron nitride, talc, mica, clay, glass flake, calcium carbonate, alumina, wollastonite, sericite, hydrotalcite, montmorillonite, and insulating graphite. [5] The resin composition according to any one of [1] to [3], wherein the inorganic filler (D1) contains boron nitride. [6] The resin composition according to any one of [1] to [5], wherein the inorganic filler (D1) is surface-treated with a silane coupling agent. [7] The resin composition according to [6], wherein the silane coupling agent includes a silane coupling agent having a vinyl group. [8] The resin composition according to any one of [1] to [7], wherein a total content of the thermosetting cyclic olefin copolymer (A), the radical polymerization initiator (B), the antioxidant (C) and the inorganic filler (D) is 50 mass% or more and 100 mass% or less, when a total amount of solid contents of the resin composition is 100 mass%. [9] The thermosetting cyclic olefin copolymer (A) contains one or more repeating units (a) derived from olefins represented by the following formula (I), one or more repeating units (b) derived from cyclic non-conjugated dienes represented by the following formula (III), and one or more repeating units (c) derived from cyclic olefins represented by the following formula (V). The resin composition according to any of [1] to [8]. [ka] In the formula (I), R 300 represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms. [ka] In the formula (III), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, and R 61 ~R76 And R a1 and R b1 may be the same or different, and each is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 104 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, t is a positive integer of 0 to 10, and R 75 and R 76 may be bonded to each other to form a monocyclic or polycyclic ring. [ka] In the above formula (V), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, R 61 ~R 78 And R a1 and R b1 may be the same or different, and each is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 75 ~R 78 may be bonded to each other to form a monocyclic or polycyclic ring.

[10] The resin composition according to any one of [1] to [9], wherein, when the total number of moles of repeating units in the thermosetting cyclic olefin copolymer (A) is taken as 100 mol %, the content of the olefin-derived repeating units (a) is 10 mol % or more and 80 mol % or less, the content of the cyclic non-conjugated diene-derived repeating units (b) is 1 mol % or more and 40 mol % or less, and the content of the cyclic olefin-derived repeating units (c) is 4 mol % or more and 60 mol % or less.

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

[10] and a solvent.

[12] A film comprising a cured product obtained by curing the resin composition according to any one of [1] to

[10] .

[13] A laminate comprising the film of

[12] .

[14] A metal clad laminate comprising a metal foil on at least one surface of the laminate according to

[13] . Effect of the Invention

[0008] According to the resin composition of the present invention, it is possible to obtain a film, a laminate, and a metal-clad laminate having an improved balance of performance such as low dielectric properties, low thermal expansion, and thermal conductivity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the present invention will be described based on the embodiment. In this embodiment, "A to B" indicating a numerical range means A or more and B or less unless otherwise specified. In addition, when a numerical range is described in stages, the upper and lower limits of each numerical range can be arbitrarily combined. Furthermore, the description of "A and / or B" is a concept that includes the case of A, the case of B, and both the cases of A and B.

[0010] [Resin composition] The resin composition of the present embodiment comprises a thermosetting cyclic olefin copolymer (A) having a crosslinkable group, a radical polymerization initiator (B), an antioxidant (C), and an inorganic filler (D), wherein the inorganic filler (D) comprises a plate-like inorganic filler (D1) having an average aspect ratio of 2 or more and 170 or less, and the content of the inorganic filler (D1) is 30 parts by mass or more and 300 parts by mass or less per 100 parts by mass of the thermosetting cyclic olefin copolymer (A).

[0011] Resins used in metal-clad laminates need to have basic properties of insulation and low thermal expansion, as well as low dielectric properties, thermal conductivity, tracking properties, flame retardancy, etc., depending on the intended use. For example, resins have low thermal conductivity, but adding additives can increase their thermal conductivity, making them suitable for use in power amplifier boards. In this case, a more advanced balance of performance is required in terms of low thermal expansion and low dielectric properties.

[0012] According to the resin composition of the present embodiment, it is possible to obtain a film, a laminate, and a metal-clad laminate that have an improved balance of performance such as low dielectric properties, low thermal expansion, and thermal conductivity. The reasons for this are thought to be as follows. It is considered that the contact area between the plate-like surface of the inorganic filler (D1) and the thermosetting cyclic olefin copolymer (A) is increased by making the average aspect ratio of the inorganic filler (D1) equal to or greater than a predetermined value, and the thermal expansion of the thermosetting cyclic olefin copolymer (A) can be suppressed. This is presumably because the plate-like surface of the inorganic filler (D1) has fewer polar groups than the end surface, and therefore has affinity with the thermosetting cyclic olefin copolymer (A) having low polarity. In addition, since the average aspect ratio of the inorganic filler (D1) is within a predetermined range, it is possible to achieve both dispersibility and coatability of the inorganic filler in the varnish, which is believed to result in improved thermal conductivity. In addition, the plate-like surface of the inorganic filler (D1) is chemically inactive to the thermosetting cyclic olefin copolymer (A), and therefore is unlikely to inhibit crosslinking of the thermosetting cyclic olefin copolymer (A). This is believed to result in a homogeneous thermosetting film with improved thermal conductivity. In addition, by setting the content of the plate-like inorganic filler (D1) to a predetermined value or more, when a film is formed, the inorganic filler (D1) can be oriented in the in-plane direction of the film, and as a result, it is considered that it is possible to achieve both low dielectric properties in the film thickness direction and low thermal expansion properties in the in-plane direction. In addition, by making the content of the plate-like inorganic filler (D1) equal to or greater than a predetermined value, the inorganic filler (D1) is filled throughout the resin composition, and paths through which heat can pass are formed between the inorganic fillers, which is thought to improve thermal conductivity.

[0013] <Thermosetting cyclic olefin copolymer (A)> The resin composition of the present embodiment contains a thermosetting cyclic olefin copolymer (A) having a crosslinkable group (hereinafter, also simply referred to as "copolymer"). The thermosetting cyclic olefin copolymer (A) can be used without any particular limitation as long as it is a copolymer that has thermosetting properties and contains repeating units derived from a cyclic olefin. In addition, the thermosetting cyclic olefin copolymer (A) has a crosslinkable group from the viewpoint of improving the heat resistance of the cured product obtained by forming a crosslinked structure. Examples of the crosslinkable group include crosslinkable functional groups such as vinyl group, vinylidene group, vinylene group, vinyl group substituted with an alkyl group, phenyl group, or alkylphenyl group, vinylidene group substituted with an alkyl group, phenyl group, or alkylphenyl group, vinylene group substituted with an alkyl group, phenyl group, or alkylphenyl group, maleimide group, thiol group, thienyl group, silyl group, epoxy group, oxazoline group, (meth)acrylic group, and carboxyl group, and preferably vinyl group. By having the crosslinkable group in the thermosetting cyclic olefin copolymer (A), a crosslinked structure can be formed between the inorganic filler (D1) surface-treated with a silane coupling agent described later, and the heat resistance can be further improved. The thermosetting cyclic olefin copolymer (A) will be described in detail below, but the thermosetting cyclic olefin copolymer (A) used in the present embodiment is not limited to the following embodiment.

[0014] From the viewpoint of further improving the balance of the dielectric properties and heat resistance of the resulting cured product, the thermosetting cyclic olefin copolymer (A) preferably contains (a) one or more olefin-derived repeating units represented by the following formula (I), (b) one or more cyclic non-conjugated diene-derived repeating units represented by the following formula (III), and (c) one or more cyclic olefin-derived repeating units represented by the following formula (V).

[0015] [ka]

[0016] In the above formula (I), R 300 represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms.

[0017] [ka]

[0018] In the above formula (III), u is 0 or 1, v is 0 or a positive integer, preferably an integer of 0 to 2, more preferably 0 or 1, w is 0 or 1, R 61 ~R 76 And R a1 and R b1 may be the same or different, and each is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 104 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, t is a positive integer of 0 to 10, and R 75 and R 76 may be bonded to each other to form a monocyclic or polycyclic ring.

[0019] [ka]

[0020] In the above formula (V), u is 0 or 1, v is 0 or a positive integer, preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, w is 0 or 1, R 61 ~R 78 And R a1 and R b1 may be the same or different, and each is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 75 ~R 78 may be bonded to each other to form a monocyclic or polycyclic ring.

[0021] In the thermosetting cyclic olefin copolymer (A), when the total mole number of repeating units in the thermosetting cyclic olefin copolymer (A) is taken as 100 mol %, the content of each repeating unit can be as follows. The content of the olefin-derived repeating unit (a) is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, even more preferably 30 mol% or more, even more preferably 35 mol% or more, even more preferably 40 mol% or more, and is preferably 80 mol% or less, more preferably 75 mol% or less, even more preferably 72 mol% or less, even more preferably 68 mol% or less, even more preferably 65 mol% or less, even more preferably 60 mol% or less. In addition, the content of the repeating unit (b) derived from a cyclic non-conjugated diene is preferably 1 mol% or more, more preferably 3 mol% or more, even more preferably 5 mol% or more, even more preferably 8 mol% or more, and preferably 40 mol% or less, more preferably 37 mol% or less, even more preferably 33 mol% or less, even more preferably 30 mol% or less, even more preferably 20 mol% or less, even more preferably 15 mol% or less. Furthermore, the content of the repeating unit (c) derived from a cyclic olefin is preferably 4 mol% or more, more preferably 6 mol% or more, even more preferably 8 mol% or more, even more preferably 10 mol% or more, even more preferably 20 mol% or more, even more preferably 25 mol% or more, even more preferably 30 mol% or more, and is preferably 60 mol% or less, more preferably 50 mol% or less, even more preferably 40 mol% or less. When the content of each repeating unit in the thermosetting cyclic olefin copolymer (A) is within the above range, the performance balance of dielectric properties and heat resistance can be improved when the film is made. Furthermore, the performance balance of mechanical properties, transparency and gas barrier properties of the film can be improved. In other words, a film with excellent balance of these physical properties can be obtained.

[0022] The olefin monomer, which is one of the copolymerization raw materials for the thermosetting cyclic olefin copolymer (A), is a monomer that provides the skeleton represented by the above formula (I) upon addition copolymerization, and is an olefin represented by the following formula (Ia).

[0023] [ka]

[0024] In the above formula (Ia), R 300 represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms. Examples of the olefin represented by formula (Ia) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Among these, at least one selected from the group consisting of ethylene and propylene is preferred, and ethylene is more preferred, from the viewpoint of further improving the performance balance of heat resistance, mechanical properties, dielectric properties, transparency, and gas barrier properties when made into a film. Two or more kinds of olefin monomers represented by the above formula (Ia) may be used. In addition, the olefin may contain at least one kind of biomass-derived monomer (biomass-derived ethylene, biomass-derived propylene, etc.).

[0025] The cyclic non-conjugated diene monomer, which is one of the copolymerization raw materials of the thermosetting cyclic olefin copolymer (A), undergoes addition copolymerization to form the repeating unit represented by the above formula (III). For example, a cyclic non-conjugated diene represented by the following formula (IIIa) corresponding to the above formula (III) is used. The cyclic non-conjugated diene may contain a constituent unit derived from a biomass-derived monomer (cyclic non-conjugated diene).

[0026] [ka]

[0027] In the above formula (IIIa), u is 0 or 1, v is 0 or a positive integer, preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, w is 0 or 1, R 61 ~R 76 And R a1 and R b1 may be the same or different, and each is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 104 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, t is a positive integer of 0 to 10, and R 75 and R 76 may be bonded to each other to form a monocyclic or polycyclic ring.

[0028] The cyclic non-conjugated diene represented by the above formula (IIIa) is not particularly limited, but examples thereof include cyclic non-conjugated dienes represented by the following chemical formulas. Among these, the cyclic non-conjugated dienes represented by the above formula (IIIa) include 5-vinyl-2-norbornene and 8-vinyl-9-methyltetracyclo[4.4.0.1 2,5 .1 7,10 ]-3-dodecene is preferred, and 5-vinyl-2-norbornene is more preferred.

[0029] [ka]

[0030] [ka]

[0031] The cyclic non-conjugated diene represented by the above formula (IIIa) can also be represented by, for example, the following formula (IIIb).

[0032] [ka]

[0033] In the above formula (IIIb), n is an integer of 0 to 10, R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R2 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

[0034] The thermosetting cyclic olefin copolymer (A) is characterized in that it contains a repeating unit derived from a cyclic non-conjugated diene represented by the above formula (III) and thus has a double bond in the side chain portion, i.e., in the portion other than the main chain of the copolymer.

[0035] The cyclic olefin monomer, which is one of the copolymerization raw materials for the thermosetting cyclic olefin copolymer (A), undergoes addition copolymerization to form the repeating unit represented by the above formula (V). For example, the cyclic olefin monomer represented by the following formula (Va) corresponding to the above formula (V) is used.

[0036] [ka]

[0037] In the above formula (Va), u is 0 or 1, v is 0 or a positive integer, preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, w is 0 or 1, R 61 ~R 78 And R a1 and R b1 may be the same or different, and each is a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R 75 ~R 78 may be bonded to each other to form a monocyclic or polycyclic ring.

[0038] Specific examples of the cyclic olefin represented by the above formula (Va) include the compounds described in WO 2006 / 118261. Cyclic olefins represented by the above formula (Va) include bicyclo[2.2.1]-2-heptene (also called "norbornene") and tetracyclo[4.4.0.1 2,5 .1 7,10 ]-3-dodecene (also called "tetracyclododecene") is preferred, and bicyclo[2.2.1]-2-heptene is more preferred. These cyclic olefins have the advantage that the elastic modulus of the copolymer and the cured product is easily maintained because they have a rigid ring structure, and that crosslinking is easily controlled because they do not contain a heterogeneous double bond structure. The cyclic olefin represented by the above formula (Va) may contain a structural unit derived from a biomass-derived monomer (cyclic olefin).

[0039] By using the olefin monomer represented by the above formula (Ia) and the cyclic olefin monomer represented by the above formula (Va) as the copolymerization components, the solubility of the thermosetting cyclic olefin copolymer (A) in a solvent is further improved, resulting in good moldability and improved product yield.

[0040] The thermosetting cyclic olefin copolymer (A) may further contain, in addition to (a) one or more olefin-derived repeating units represented by the above formula (I), (b) one or more cyclic olefin-derived repeating units represented by the above formula (III), and (c) one or more cyclic olefin-derived repeating units represented by the above formula (V), at least one repeating unit selected from the group consisting of repeating units derived from cyclic olefins other than the cyclic non-conjugated diene represented by the above formula (III) and the cyclic olefin represented by the formula (V), and repeating units derived from linear polyenes. In this case, as the copolymerization raw materials for the thermosetting cyclic olefin copolymer (A), in addition to the olefin monomer represented by formula (Ia), the cyclic non-conjugated diene monomer represented by formula (IIIa), and the cyclic olefin monomer represented by formula (Va), a cyclic olefin monomer other than the cyclic non-conjugated diene monomer represented by formula (IIIa) and the cyclic olefin monomer represented by formula (Va), and / or a chain polyene monomer can be used. Examples of such cyclic olefin monomers and linear polyene monomers include cyclic olefins represented by the following formula (VIa), cyclic olefins represented by the following formula (VIIa), linear polyenes represented by the following formula (VIIIa), etc. Two or more different types of these cyclic olefins and linear polyenes may be used.

[0041] [ka]

[0042] In the above formula (VIa), x and d are 0 or an integer of 1 or more, preferably an integer of 0 or more and 2 or less, more preferably 0 or 1, y and z are 0, 1, or 2, and R 81 ~R 99 may be the same or different, and each is a hydrogen atom, a halogen atom, an aliphatic hydrocarbon group which is an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or an alkoxy group; R 89 and R 90 and the carbon atom to which R is bonded. 93 or the carbon atom to which R 91 may be bonded directly or via an alkylene group having 1 to 3 carbon atoms, and when y=z=0, R 95 and R 92 or R 95 and R 99 may be bonded to each other to form a monocyclic or polycyclic aromatic ring.

[0043] [ka]

[0044] In the above formula (VIIa), R 100 and R 101 may be the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and f is 1≦f≦18.

[0045] [ka]

[0046] In the above formula (VIIIa), R 201 From R 206 may be the same or different and are each a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and P is a linear or branched hydrocarbon group having 1 to 20 carbon atoms which may contain a double bond and / or a triple bond.

[0047] Specific examples of the cyclic olefin represented by the above formula (VIa) and formula (VIIa) that can be used include the compounds described in paragraphs 0037 to 0063 of WO 2006 / 118261.

[0048] Examples of the linear polyene represented by the formula (VIIIa) include 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5-dimethyl-1,4-hexadiene, 7-methyl-1,6-octadiene, DMDT, 1,3-butadiene, 1,5-hexadiene, etc. Cyclizable polyenes cyclized from polyenes such as 1,3-butadiene and 1,5-hexadiene may also be used.

[0049] When the thermosetting cyclic olefin copolymer (A) contains a repeating unit derived from a chain polyene represented by the above formula (VIIIa), or a repeating unit derived from a cyclic non-conjugated diene represented by the above formula (III) and a cyclic olefin other than the cyclic olefin represented by the above formula (V) [e.g., the above formula (VIa) and formula (VIIa)], the content of the repeating units is, for example, 0.1 mol % or more and 100 mol % or less, preferably 0.1 mol % or more and 50 mol % or less, based on the total molar number of repeating units derived from one or more olefins represented by the above formula (I), repeating units derived from one or more cyclic non-conjugated dienes represented by the above formula (III), and repeating units derived from one or more cyclic olefins represented by the above formula (V).

[0050] By using the olefin monomer represented by the above-mentioned formula (I), the cyclic olefin represented by the formula (VIa) or (VIIa), and the linear polyene represented by the formula (VIIIa) as the copolymerization components, the effect according to the present embodiment can be obtained, and the solubility of the thermosetting cyclic olefin copolymer (A) in a solvent is further improved, so that the moldability is good and the product yield is improved. Among these, the cyclic olefin represented by the formula (VIa) or (VIIa) is preferred. These cyclic olefins have a rigid ring structure, so that the elastic modulus of the thermosetting cyclic olefin copolymer (A) and the film is easily maintained, and they have the advantage of being easy to control crosslinking because they do not contain a heterogeneous double bond structure.

[0051] The number average molecular weight (Mn) of the thermosetting cyclic olefin copolymer (A) measured by gel permeation chromatography in terms of polystyrene is preferably 1,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, and even more preferably 6,000 or more, from the viewpoint of further improving the balance of performance among the dielectric properties, heat resistance, and mechanical properties, and is preferably 100,000 or less, more preferably 80,000 or less, even more preferably 60,000 or less, even more preferably 40,000 or less, even more preferably 30,000 or less, and even more preferably 10,000 or less, from the viewpoint of further improving moldability such as impregnation into a fiber base material and wiring embedding ability when producing a printed wiring board. The number average molecular weight (Mn) of the thermosetting cyclic olefin copolymer (A) can be controlled by the polymerization conditions such as the polymerization catalyst, co-catalyst, amount of H2 added, and polymerization temperature.

[0052] The comonomer content and glass transition temperature (Tg) of the thermosetting cyclic olefin copolymer (A) can be controlled by the monomer charging ratio according to the intended use. The Tg of the thermosetting cyclic olefin copolymer (A) is, for example, 300°C or less, preferably 280°C or less, more preferably 260°C or less, even more preferably 240°C or less, even more preferably 220°C or less, even more preferably 200°C or less, even more preferably 170°C or less, and even more preferably 150°C or less. When the Tg is equal to or less than the upper limit, the melt moldability of the thermosetting cyclic olefin copolymer (A) and its solubility in a solvent when it is made into a varnish are improved.

[0053] The intrinsic viscosity [η] of the thermosetting cyclic olefin copolymer (A) measured in decalin at 135°C is, for example, 0.10 dl / g or more, preferably 0.15 dl / g or more, and, for example, 15 dl / g or less, preferably 5 dl / g or less, more preferably 3 dl / g or less. When the intrinsic viscosity [η] is equal to or less than the upper limit, moldability can be further improved. When the intrinsic viscosity [η] is equal to or more than the lower limit, heat resistance and mechanical properties of the cured product can be further improved. The intrinsic viscosity [η] of the thermosetting cyclic olefin copolymer (A) can be controlled by the polymerization conditions such as the polymerization catalyst, co-catalyst, amount of H2 added, and polymerization temperature.

[0054] The content of the thermosetting cyclic olefin copolymer (A) in the resin composition of this embodiment, when the entire resin composition is taken as 100 mass%, is, from the viewpoint of further improving the performance balance of heat resistance, mechanical properties and low dielectric properties of the cured product, preferably 10 mass% or more, more preferably 12 mass% or more, even more preferably 14 mass% or more, even more preferably 15 mass% or more, even more preferably 20 mass% or more, even more preferably 25 mass% or more, even more preferably 30 mass% or more, and is preferably 80 mass% or less, more preferably 70 mass% or less, even more preferably 60 mass% or less, even more preferably 55 mass% or less, and even more preferably 50 mass% or less.

[0055] <Production method of thermosetting cyclic olefin copolymer (A)> The thermosetting cyclic olefin copolymer (A) according to this embodiment can be produced, for example, according to the method for producing a cyclic olefin copolymer described in paragraphs 0075 to 0219 of WO 2012 / 046443. Details are omitted here.

[0056] <Radical polymerization initiator (B)> The resin composition of the present embodiment contains a radical polymerization initiator (B). Crosslinking with the radical polymerization initiator (B) can be performed by the same method as that used for polyolefins, etc. That is, a radical polymerization initiator such as dicumyl peroxide is mixed with the thermosetting cyclic olefin copolymer (A), and the mixture is heated to crosslink the copolymer.

[0057] As the radical polymerization initiator (B), known thermal radical polymerization initiators, photoradical polymerization initiators, and combinations thereof can be used. When using a thermal radical polymerization initiator among these radical polymerization initiators, the 10-hour half-life temperature is, for example, 80°C or higher, preferably 120°C or higher, from the viewpoint of storage stability. Examples of such thermal radical polymerization initiators include dialkyl peroxides such as dicumyl peroxide, t-butylcumyl peroxide, 2,5-bis(t-butylperoxy)2,5-dimethylhexane, 2,5-bis(t-butylperoxy)2,5-dimethylhexyne-3, di-t-butyl peroxide, isopropylcumyl-t-butyl peroxide, and bis(α-t-butylperoxyisopropyl)benzene; 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclododecane, n-butyl-4,4-bis(t-butylperoxy)valerate, and ethyl-3,3-bis(t-butylperoxy). peroxyketals such as bis(t-butylperoxy)isophthalate, t-butylperoxybenzoate, t-butylperoxyacetate, etc.; hydroperoxides such as t-butyl hydroperoxide, t-hexyl hydroperoxide, cumin hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, etc.; bibenzyl compounds such as 2,3-dimethyl-2,3-diphenylbutane, etc.; 3,3,5,7,7-pentamethyl-1,2,4-trioxepane, etc.

[0058] Among the radical polymerization initiators (B), examples of the photoradical polymerization initiator include benzoin alkyl ether, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzophenone, methylbenzoyl formate, isopropyl thioxanthone, and mixtures of two or more of these. In addition, a sensitizer can be used together with these photoradical polymerization initiators. Examples of the sensitizer include carbonyl compounds such as anthraquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, benzanthrone, p,p'-tetramethyldiaminobenzophenone, and chloranil; nitro compounds such as nitrobenzene, p-dinitrobenzene, and 2-nitrofluorene; aromatic hydrocarbons such as anthracene and chrysene; sulfur compounds such as diphenyl disulfide; and nitrogen compounds such as nitroaniline, 2-chloro-4-nitroaniline, 5-nitro-2-aminotoluene, and tetracyanoethylene.

[0059] The content of the radical polymerization initiator (B) in the resin composition of this embodiment is, from the viewpoint of further improving the performance balance of low dielectric properties and heat resistance of the obtained cured product, preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, even more preferably 1.5 parts by mass or more, even more preferably 1.8 parts by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 3.0 parts by mass or more, even more preferably 4.0 parts by mass or more, and is preferably 8.0 parts by mass or less, more preferably 7.5 parts by mass or less, even more preferably 7.0 parts by mass or less, even more preferably 6.5 parts by mass or less, even more preferably 6.0 parts by mass or less, even more preferably 5.0 parts by mass or less, and even more preferably 4.5 parts by mass or less, per 100 parts by mass of the thermosetting cyclic olefin copolymer (A).

[0060] The resin composition according to the present embodiment may further include a crosslinking aid. There is no limitation on the crosslinking aid, but examples thereof include oximes such as p-quinone dioxime and p,p'-dibenzoyl quinone dioxime; acrylates or methacrylates such as ethylene dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, cyclohexyl methacrylate, acrylic acid / zinc oxide mixture, and allyl methacrylate; vinyl monomers such as divinylbenzene, vinyl toluene, and vinyl pyridine; allyl compounds such as hexamethylene diallyl nadiimide, diaryl itaconate, diallyl phthalate, diallyl isophthalate, diallyl monoglycidyl isocyanurate, triallyl cyanurate, and triallyl isocyanurate; and maleimide compounds such as N,N'-m-phenylene bismaleimide and N,N'-(4,4'-methylene diphenylene) dimaleimide. These crosslinking aids may be used alone or in combination.

[0061] <Antioxidants (C)> The resin composition of the present embodiment contains an antioxidant (C). The antioxidant (C) is not limited, and a known antioxidant can be used, such as a phenol-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, or a thioether-based antioxidant.

[0062] Examples of the phenol-based antioxidant include acrylate-based phenol compounds described in JP-A-63-179953 and JP-A-1-168643, such as 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate and 2,4-di-t-amyl-6-(1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl)phenyl acrylate; 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, octadecyl-3-phenylpropanol, and the like. -(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2,2'-methylene-bis(4-methyl-6-t-butylphenol), 4,4'-butylidene-bis(6-t-butyl-m-cresol), 4,4'-thiobis(3-methyl-6-t-butylphenol), bis(3-cyclohexyl-2-hydroxy-5-methylphenyl)methane, 3,9-bis(2-(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy)-1,1-dimethylethyl)-2,4,8,10-tetrahydrofuran Alkyl-substituted phenols such as xaspiro[5.5]undecane, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, triethylene glycol bis(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate), and tocopherol triazine group-containing phenol compounds such as 6-(4-hydroxy-3,5-di-t-butylanilino)-2,4-bisoctylthio-1,3,5-triazine, 6-(4-hydroxy-3,5-dimethylanilino)-2,4-bisoctylthio-1,3,5-triazine, 6-(4-hydroxy-3-methyl-5-t-butylanilino)-2,4-bisoctylthio-1,3,5-triazine, and 2-octylthio-4,6-bis-(3,5-di-t-butyl-4-oxyanilino)-1,3,5-triazine.Among these, acrylate-based phenol compounds and alkyl-substituted phenol compounds are preferred, and alkyl-substituted phenol compounds are more preferred.

[0063] Examples of phosphorus-based antioxidants include triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl)phosphite, tris(dinonylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, tris(2-t-butyl-4-methylphenyl)phosphite, tris(cyclohexylphenyl)phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)phosphite, monophosphite compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene; 4,4'-butylidene-bis(3-methyl-6-t-butylphenanthren) nyl-di-tridecyl phosphite), 4,4'-isopropylidene-bis(phenyl-di-alkyl (C12-C15) phosphite), 4,4'-isopropylidene-bis(diphenyl monoalkyl (C12-C15) phosphite), 1,1,3-tris(2-methyl-4-di-tridecyl phosphite-5-t-butylphenyl)butane, tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphite, cyclic neo Examples of the diphosphite compounds include pentanetetraylbis(isodecyl phosphite), cyclic neopentanetetraylbis(nonylphenyl phosphite), cyclic neopentanetetraylbis(2,4-di-t-butylphenyl phosphite), cyclic neopentanetetraylbis(2,4-dimethylphenyl phosphite), and cyclic neopentanetetraylbis(2,6-di-t-butylphenyl phosphite). Among these, monophosphite compounds are preferred, and tris(nonylphenyl)phosphite, tris(dinonylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, and the like are more preferred.

[0064] Examples of sulfur-based antioxidants include dilauryl 3,3-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3-thiodipropionate, laurylstearyl 3,3-thiodipropionate, pentaerythritol-tetrakis-(β-lauryl-thio-propionate), 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, and the like.

[0065] Examples of thioether antioxidants include tetrakis{methylene-3-(laurylthio)propionate}methane, bis[methyl-4-{3-n-alkyl(C12 or C14)thiopropioniodyl}-5-t-butylphenyl]sulfide, and ditridecyl-3,3'-thiodipropionate.

[0066] The content of the antioxidant (C) in the resin composition of this embodiment is, from the viewpoint of further improving the performance balance of low dielectric properties and heat resistance of the obtained cured product, preferably 0.1 part by mass or less, more preferably 0.08 part by mass or less, even more preferably 0.07 part by mass or less, and is preferably 0.01 part by mass or more, more preferably 0.03 part by mass or more, and even more preferably 0.05 part by mass or more, per 100 parts by mass of the thermosetting cyclic olefin copolymer (A).

[0067] <Inorganic filler (D)> The resin composition of the present embodiment contains an inorganic filler (D), and the inorganic filler (D) contains a plate-like inorganic filler (D1). The term "plate-like" refers to a thin plate or flake shape, and the dimension in the long axis direction within the plate-like shape is longer than the thickness of the inorganic filler. The plate-like inorganic filler can improve the balance of performances of mechanical strength, dimensional stability, and orientation. The average aspect ratio of the inorganic filler (D1) is 2 or more, preferably 5 or more, more preferably 10 or more, even more preferably 30 or more, and even more preferably 40 or more. The average aspect ratio of the inorganic filler (D) is 170 or less, preferably 150 or less, more preferably 140 or less, even more preferably 130 or less, even more preferably 120 or less, even more preferably 110 or less, even more preferably 100 or less, even more preferably 80 or less, even more preferably 60 or less, and even more preferably 50 or less. Here, the average aspect ratio is the average particle size D measured by the laser diffraction scattering method described later. 50 The thickness t and average particle diameter D per average disk-shaped particle, assuming that the particles of the inorganic filler (D1) are disk-shaped, are expressed by the following formulas (1) and (2) using the true density ρ measured by the pycnometer method in accordance with JIS R1620:1995 and the specific surface area S measured by the BET specific surface area method in accordance with JIS Z8830:2013. 50 Ratio of (D 50 / t). Equation (1): Particle thickness t = 2 × D 50 / (S×ρ×D 50 -4) Equation (2): Average aspect ratio = 0.5 × S × ρ × D 50 -2 By making the average aspect ratio of the inorganic filler (D1) equal to or less than the upper limit, the bulk of the inorganic filler can be appropriately reduced, and the moldability of the resin composition of the present embodiment can be improved. Also, by making the average aspect ratio of the inorganic filler (D1) equal to or more than the lower limit, the particles have a shape (not spherical) with a major axis diameter relative to a minor axis diameter, which facilitates particle orientation and improves low dielectric properties.

[0068] The inorganic filler (D1) is an insulating inorganic filler, and preferably contains at least one selected from the group consisting of boron nitride, talc, mica, clay, glass flake, calcium carbonate, alumina, wollastonite, sericite, hydrotalcite, montmorillonite, and insulating graphite, and more preferably contains boron nitride. Since the plate-like surface of boron nitride is chemically inactive to the thermosetting cyclic olefin copolymer (A), it is unlikely to inhibit the crosslinking of the thermosetting cyclic olefin copolymer (A). Therefore, the obtained thermosetting film is homogeneous and has improved thermal conductivity.

[0069] Boron nitride is a compound consisting of nitrogen and boron, and an example is hexagonal boron nitride (h-BN) in the normal pressure phase. In hexagonal boron nitride, nitrogen and boron are alternately arranged at each vertex of a regular hexagon to form a continuous plane, and the planes are stacked so that the vertices of regular hexagons located at the same position in upper and lower layers alternate between nitrogen and boron.

[0070] The inorganic filler (D1) of this embodiment is preferably surface-treated with a silane coupling agent. The silane coupling agent may include one or more types selected from known silane coupling agents such as various silane-based compounds such as epoxysilane, mercaptosilane, aminosilane such as phenylaminosilane, alkylsilane, ureidosilane, vinylsilane, methacrylsilane, etc. Among them, vinylsilane having a vinyl group is preferred. The vinyl silane preferably includes one or more compounds selected from the group consisting of 7-octenyltrimethoxysilane, 6-heptenyltriethoxysilane, 6-heptenyltrimethoxysilane, 5-hexenyltriethoxysilane, 5-hexenyltrimethoxysilane, 4-pentenyltriethoxysilane, 4-pentenyltrimethoxysilane, 3-butenyltriethoxysilane, 3-butenyltrimethoxysilane, 2-propenyltriethoxysilane, 2-propenyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane having a long-chain alkyl group, a branched alkyl group or a branched alkoxy group having up to 16 carbon atoms, vinyltrimethoxysilane, p-styryltrimethoxysilane and p-styryltriethoxysilane, and more preferably includes 7-octenyltrimethoxysilane. Since the surface, especially the end faces, of the plate-like inorganic filler (D1) contains a small amount of polar groups, the surface can be treated with a non-polar agent such as a silane coupling agent to further improve the thermal conductivity while maintaining low dielectric properties. In addition, by making the surface non-polar with a silane coupling agent, the plate-like surface of the inorganic filler (D1) can be further prevented from inhibiting the crosslinking of the thermosetting cyclic olefin copolymer (A). In particular, surface treatment with vinylsilane enables direct chemical bonding between the inorganic filler (D1) and the thermosetting cyclic olefin copolymer (A), thereby further improving thermal conductivity in the thickness direction, and further improving heat resistance and peel strength.

[0071] The method of surface-treating the inorganic filler (D1) with a silane coupling agent is not limited, and a known method can be used. As a method of surface-treating the inorganic filler (D1) with a silane coupling agent by a wet method using a solvent, for example, the inorganic filler (D1) is dispersed in a solvent such as toluene, and heated and stirred at 80°C for 10 minutes. Next, a diluted solution in which the silane coupling agent is dissolved in a solvent such as toluene is dropped into the dispersion, and the dispersion is heated and stirred at 80°C for about 3 hours. After that, it is cooled to room temperature and washed with toluene and acetone to obtain an inorganic filler surface-treated with a silane coupling agent. When the inorganic filler (D1) is surface-treated with a silane coupling agent by a wet method using a solvent, the amount of the silane coupling agent added is, from the viewpoint of carrying out the reaction sufficiently, preferably 50 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, and preferably 150 parts by mass or less, more preferably 120 parts by mass or less, even more preferably 110 parts by mass or less, per 100 parts by mass of the inorganic filler (D1).

[0072] Average particle size D of inorganic filler (D1) 50is preferably 0.1 μm or more, more preferably 0.3 μm or more, even more preferably 0.5 μm or more, even more preferably 0.8 μm or more, even more preferably 1.0 μm or more, even more preferably 3.0 μm or more, even more preferably 5.0 μm or more, and is preferably 30.0 μm or less, more preferably 20.0 μm or less, even more preferably 15.0 μm or less, even more preferably 10.0 μm or less, even more preferably 9.0 μm or less, even more preferably 8.0 μm or less, even more preferably 7.0 μm or less. Here, the average particle size D of the inorganic filler (D1) 50 represents the particle size at which the cumulative frequency is 50% on a volume-based cumulative frequency distribution curve measured by a laser diffraction particle size distribution measurement method in accordance with JIS Z8825:2013. Average particle size D of inorganic filler (D1) 50 By making the average particle diameter D of the inorganic filler (D1) equal to or less than the upper limit, the balance of the performances of low thermal expansion and thermal conductivity can be further improved. 50 When the average particle diameter D of the inorganic filler (D1) is equal to or larger than the lower limit, the resin composition can be more uniformly dispersed in a solvent when the resin composition is made into a varnish. 50 If the content is below the lower limit, the inorganic filler (D1) is treated as a nanomaterial, which imposes large restrictions on equipment at the production site.

[0073] The volume resistivity of the inorganic filler (D1) at 23° C. is preferably 1.0×10 8 Ω cm or more, preferably 1.0×10 10 Ω cm or more, more preferably 1.0×10 12 Ω cm or more, more preferably 1.0×10 13 Ω·cm or more. There is no upper limit to the volume resistivity of the inorganic filler (D1) at 23° C., but it is not particularly limited. 18 It may be less than Ω cm, and may be 1.0×10 17 It may be less than Ω cm, and may be 1.0×10 16 It may be Ω·cm or less.

[0074] The content of the inorganic filler (D1) in the resin composition of this embodiment is 30 parts by mass or more, preferably 40 parts by mass or more, more preferably 60 parts by mass or more, even more preferably 80 parts by mass or more, and even more preferably 90 parts by mass or more, based on 100 parts by mass of the thermosetting cyclic olefin copolymer (A). The content of the inorganic filler (D1) in the resin composition of this embodiment is 300 parts by mass or less, preferably 280 parts by mass or less, more preferably 250 parts by mass or less, even more preferably 230 parts by mass or less, and even more preferably 210 parts by mass or less, based on 100 parts by mass of the thermosetting cyclic olefin copolymer (A). By making the content of the inorganic filler (D1) equal to or less than the upper limit, the balance of the performance between low thermal expansion and thermal conductivity can be improved. Also, by making the content of the inorganic filler (D1) equal to or more than the lower limit, the moldability of the resin composition can be improved, and the appearance of the film when made into a film can be improved. The content of the inorganic filler (D1) in the resin composition of the present embodiment can be determined by a known analytical method, for example, by thermogravimetric analysis (TGA). For example, using a thermogravimetric analyzer (TGA), the mass fraction of the residue after holding a 5 mg sample in air at 900° C. for 1 hour can be determined as the content of the inorganic filler (D1).

[0075] As the inorganic filler (D), an inorganic filler other than the inorganic filler (D1) can be used. Examples of inorganic fillers other than the inorganic filler (D1) include silica, alumina, diatomaceous earth, titanium oxide, magnesium oxide, aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, asbestos, calcium silicate, montmorillonite, bentonite, graphite, aluminum powder, molybdenum sulfide, boron fiber, silicon carbide fiber, polyethylene fiber, polypropylene fiber, polyester fiber, and polyamide fiber. The content of inorganic fillers other than the inorganic filler (D1) in the resin composition of this embodiment is preferably 200 parts by mass or less, more preferably 180 parts by mass or less, even more preferably 150 parts by mass or less, even more preferably 130 parts by mass or less, and even more preferably 110 parts by mass or less, per 100 parts by mass of the thermosetting cyclic olefin copolymer (A), from the viewpoint of further improving the performance balance of low thermal expansion, thermal conductivity, and film formability. There is no lower limit for the content of the inorganic filler other than the inorganic filler (D1) in the resin composition of this embodiment, but for example, it may be 0 parts by mass or more, 30 parts by mass or more, 50 parts by mass or more, 80 parts by mass or more, or 100 parts by mass or more, relative to 100 parts by mass of the thermosetting cyclic olefin copolymer (A).

[0076] In the resin composition of this embodiment, the total content of the thermosetting cyclic olefin copolymer (A), the radical polymerization initiator (B), the antioxidant (C) and the inorganic filler (D) is, when the total amount of solids in the resin composition (the total amount of components remaining as solids when cured) is taken as 100 mass%, from the viewpoint of further improving the performance balance of low dielectric properties, low thermal expansion properties and thermal conductivity, preferably 50 mass% or more, more preferably 60 mass% or more, even more preferably 80 mass% or more, even more preferably 90 mass% or more, and preferably 100 mass% or less.

[0077] <Other ingredients> The resin composition of the present embodiment may contain other components as long as the effects of the present invention are not impaired. Examples of other components include at least one additive selected from the group consisting of heat stabilizers, weather stabilizers, radiation resistance agents, plasticizers, lubricants, release agents, nucleating agents, friction and wear improvers, flame retardants, foaming agents, antistatic agents, colorants, antifogging agents, antiblocking agents, impact resistance agents, surface wetting improvers, fillers, hydrochloric acid absorbents, and metal deactivators, as well as resins other than the thermosetting cyclic olefin copolymer (A), such as epoxy resins, polystyrene resins, and polyphenylene ether (PPE) resins.

[0078] <Method for preparing resin composition> The resin composition of this embodiment can be prepared by mixing the thermosetting cyclic olefin copolymer (A), the radical polymerization initiator (B), the antioxidant (C), and the inorganic filler (D), and other components as necessary. As a mixing method, a melt blending method using an extruder or the like, or a solution blending method in which the components are dissolved and dispersed in a suitable solvent, for example, a saturated hydrocarbon such as heptane, hexane, decane, or cyclohexane; or an aromatic hydrocarbon such as toluene, benzene, or xylene, can be used.

[0079] Hereinafter, the physical properties of the cured product of the resin composition of this embodiment will be described.

[0080] In order to further improve the balance of low dielectric properties and heat resistance, the dielectric loss tangent Df of the cured product of the resin composition of this embodiment is preferably 0.0010 or less, more preferably 0.0009 or less, and even more preferably 0.0008 or less at a frequency of 10 GHz. There is no lower limit for the dielectric tangent Df, but it may be, for example, 0.0001 or more, 0.0003 or more, or 0.0005 or more. The dielectric loss tangent Df of the cured product of the resin composition of this embodiment is the dielectric loss tangent Df at 10 GHz, which is measured by cutting a test piece of 50 mm in length, 50 mm in width, and approximately 50 μm in thickness from the cured product of the resin composition and measuring the test piece by a cylindrical cavity resonator method under conditions of 23±2°C and 50±5% RH.

[0081] From the viewpoint of further reducing thermal expandability, the linear expansion coefficient of the cured product of the resin composition of this embodiment is preferably 45 ppm / K or less, more preferably 40 ppm / K or less, even more preferably 35 ppm / K or less, even more preferably 30 ppm / K or less, even more preferably 25 ppm / K or less, and even more preferably 20 ppm / K or less. There is no lower limit for the linear expansion coefficient of the cured product of the resin composition of the present embodiment, but it may be, for example, 1 ppm / K or more, 5 ppm / K or more, 10 ppm / K or more, or 15 ppm / K or more. The linear expansion coefficient is measured as follows. The cured product of the resin composition of this embodiment is cut into a test piece having a length of 20 mm, a width of 4 mm, and a thickness of about 50 μm, and is measured using a thermomechanical analyzer under the conditions of a measurement temperature range of 5 to 300° C., a heating rate of 5° C. / min, a test load of 5 kgf, in a nitrogen atmosphere, and in a film stretching mode, to calculate the linear expansion coefficient at 25 to 90° C. The unit of the linear expansion coefficient is ppm / K.

[0082] From the viewpoint of further improving thermal conductivity in the in-plane direction, the thermal conductivity in the cured product of the resin composition of this embodiment is preferably 1.0 W / (m·K) or more, more preferably 1.5 W / (m·K) or more, even more preferably 2.0 W / (m·K) or more, and even more preferably 2.5 W / (m·K) or more. There is no upper limit to the thermal conductivity in the in-plane direction in the cured product of the resin composition, but it may be, for example, 15.0 W / (m·K) or less, 10.0 W / (m·K) or less, 5.0 W / (m·K) or less, or 4.0 W / (m·K) or less.

[0083] From the viewpoint of further improving thermal conductivity in the thickness direction, the cured product of the resin composition of this embodiment has a thermal conductivity in the thickness direction of preferably 0.20 W / (m·K) or more, more preferably 0.30 W / (m·K) or more, even more preferably 0.40 W / (m·K) or more, even more preferably 0.50 W / (m·K) or more, and even more preferably 0.60 W / (m·K) or more. There is no upper limit to the thermal conductivity in the thickness direction of the cured product of the resin composition, but it may be, for example, 8.0 W / (m·K) or less, 5.0 W / (m·K) or less, 2.0 W / (m·K) or less, or 1.0 W / (m·K) or less.

[0084] The thermal conductivity in the in-plane direction and the thickness direction of the cured product of the resin composition of the present embodiment is measured as follows. A test piece measuring 30 mm in length, 5 mm in width, and approximately 50 μm in thickness is cut out from the cured resin composition. The thermal diffusivity, specific heat capacity, and density of the test piece obtained at 23° C. are then measured, and the thermal conductivity in the in-plane direction and thickness direction is calculated using the following formula (3). Equation (3): Thermal conductivity (κ) = thermal diffusivity (α) × specific heat capacity (Cp) × density (ρ) The thermal diffusivity in the in-plane direction of the cured resin composition is measured by an optical alternating current method, the thermal diffusivity in the thickness direction of the cured resin composition is measured by a temperature wave thermal analysis method, and the specific heat is measured by a differential scanning calorimetry method.

[0085] The cured product of the resin composition of the present embodiment used in measuring the various physical properties described above is prepared under the following conditions. The resin composition of this embodiment is dispersed in toluene in an amount of 400 parts by mass per 100 parts by mass of the thermosetting cyclic olefin copolymer (A) to prepare a varnish. The obtained varnish is applied to a release-treated PET film using an automatic coater at room temperature, applicator gap: 200 μm, and a speed of 10 mm / sec. Then, the film is dried at 150° C. for 4 minutes under a nitrogen atmosphere to form a film. Then, two films are stacked, and the film is pressurized to 3.5 MPa by a vacuum press under conditions of a vacuum degree of 1.2 kPa or less, and the temperature is increased at a constant rate from 25° C. and maintained at 180° C. for 120 minutes to obtain a cured product with a thickness of about 50 μm.

[0086] [varnish] The resin composition of the present embodiment can be made into a varnish by mixing with a solvent. The solvent for preparing the varnish is not limited as long as it does not impair the solubility or affinity of the thermosetting cyclic olefin copolymer (A), the radical polymerization initiator (B), the antioxidant (C) and the inorganic filler (D). As the solvent, preferred are saturated hydrocarbons such as heptane, hexane, octane, and decane; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, and decahydronaphthalene; aromatic hydrocarbons such as toluene, benzene, xylene, mesitylene, and pseudocumene; alcohols such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, and acetophenone; cellosolves such as methyl cellosolve and ethyl cellosolve; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate; and halogenated hydrocarbons such as trichloroethylene, dichloroethylene, and chlorobenzene. From the viewpoint of further improving the solubility of the resin composition and ease of availability, heptane, decane, cyclohexane, methylcyclohexane, decahydronaphthalene, toluene, benzene, xylene, mesitylene, and pseudocumene are more preferably used. These solvents may be used alone or in combination of two or more in any ratio. From the viewpoint of further improving the handling and coatability of the varnish, the amount of solvent added to the resin composition is preferably 100 parts by mass or more, more preferably 120 parts by mass or more, and preferably 400 parts by mass or less, more preferably 300 parts by mass or less, and even more preferably 250 parts by mass or less, relative to 100 parts by mass of the entire resin composition. In addition, the total content of the thermosetting cyclic olefin copolymer (A), the radical polymerization initiator (B), the antioxidant (C) and the inorganic filler (D) in the varnish is preferably 15 mass% or more, more preferably 30 mass% or more, even more preferably 50 mass% or more, still more preferably 70 mass% or more, and is preferably less than 100 mass%. In the resin composition of this embodiment, the average particle diameter D 50 Since the amount of the resin composition is equal to or less than the upper limit of the predetermined range, the dispersibility of the resin composition in a solvent can be improved.

[0087] In this embodiment, the method for preparing the varnish may be carried out by any method, for example, including a step of mixing the resin composition and the solvent. The mixing of each component is not limited in order, and can be carried out in any manner, such as all at once or in portions. There is also no limitation on the apparatus for preparing the varnish, and any apparatus capable of stirring and mixing, such as a batch type or a continuous type, may be used. The temperature at which the varnish is prepared can be selected arbitrarily from room temperature to the boiling point of the solvent. The varnish may be prepared by using the reaction solution obtained when the thermosetting cyclic olefin copolymer (A) is obtained as it is as a solvent.

[0088] [Cured product] The cured product can be obtained by crosslinking the thermosetting cyclic olefin copolymer (A) in the resin composition of the present embodiment. The crosslinking can be performed by a crosslinking step in which the resin composition is crosslinked at 150° C. or higher under a vacuum of 20 kPa or lower. The crosslinking temperature in the crosslinking step is preferably 150°C or higher, more preferably 160°C or higher, and even more preferably 170°C or higher, from the viewpoint of further improving the heat resistance of the obtained cured product, and is preferably 250°C or lower, more preferably 230°C or lower, even more preferably 220°C or lower, and even more preferably 200°C or lower, from the viewpoint of suppressing thermal decomposition of the thermosetting cyclic olefin copolymer (A) and the cured product. In order to further improve the balance of the dielectric properties and heat resistance of the resulting cured product, the crosslinking step is carried out under a vacuum of 20 kPa or less, preferably 10 kPa or less, more preferably 5 kPa or less, and even more preferably 2 kPa or less.

[0089] The crosslinking step can be carried out with the resin composition according to the present embodiment in a molten state, or with the resin composition dissolved or dispersed in a solvent in a solution state. The crosslinking step can also be carried out by volatilizing the solvent from the solution state in which the resin composition is dissolved in a solvent, forming the resin composition into any shape such as a film or coating, and then further proceeding with the crosslinking reaction. When the reaction is carried out in a molten state, the mixture of raw materials is melt-kneaded and reacted using a kneading device such as a mixing roll, a Banbury mixer, an extruder, a kneader, a continuous mixer, etc. In addition, the crosslinking reaction can be further carried out after molding by any method. When the reaction is carried out in a solution state, the same solvents as those used in the above solution blending method can be used as the solvent.

[0090] [film] The cured product obtained by curing the resin composition according to this embodiment can be formed into a film and used for various applications. As a method for curing the resin composition according to this embodiment to form a cured product and then forming it into a film, various known methods can be applied. For example, a method can be mentioned in which the above-mentioned varnish is applied to a supporting substrate such as a thermoplastic resin film, dried, and then the resin composition is crosslinked by heat treatment or the like to obtain a cured product, and a film made of the resin composition according to this embodiment is formed. As the thermoplastic resin film, a PET film, a polyimide resin film, or the like can be used. The method for applying the varnish to the supporting substrate is not particularly limited, but examples thereof include application using a spin coater, application using a spray coater, and application using a bar coater. Another example of a method is to melt-molde the resin composition according to this embodiment to obtain a film, and then crosslink the resin composition by a heat treatment or the like to form a cured product, thereby forming a film made of the resin composition according to this embodiment.

[0091] [Laminate] The film according to the present embodiment can be laminated on a substrate and used as a laminate for various applications. For example, it can be used as an organic insulating film that requires low dielectric properties, or as a curable adhesive sheet for a device having an adhesive layer. Various known methods can be applied as a method for forming the laminate according to the present embodiment. For example, a laminate can be produced by laminating the film produced by the above-mentioned method onto a substrate, and, if necessary, heat curing the laminate by a press or the like. Alternatively, a laminate can be produced by laminating an electrical insulating layer containing the above-mentioned cured product onto a conductor layer.

[0092] [Multi-layer molded body or multi-layer laminated film] The cured product obtained by curing the resin composition according to this embodiment may be formed on the surface layer of various multi-layer molded articles or multi-layer laminate films. Examples of various multilayer molded bodies or multilayer laminated films include a multilayer molded body for an optical lens in which a film according to the present embodiment is formed on the surface of a resin optical lens, and a multilayer gas barrier film in which a film according to the present embodiment is formed on the surface of a resin film such as a PET film or a PE film to impart gas barrier properties.

[0093] [Prepreg] The prepreg is formed by combining the resin composition according to this embodiment with a sheet-like fiber base material. The method for producing the prepreg is not particularly limited, and various known methods can be applied. For example, there is a method including a step of impregnating a sheet-like fiber substrate with the above-mentioned varnish to obtain an impregnated body, and a step of heating the obtained impregnated body to dry the solvent contained in the varnish. The impregnation of the sheet-like fiber substrate with the varnish can be carried out, for example, by applying a predetermined amount of varnish to the sheet-like fiber substrate by a known method such as spray coating, dip coating, roll coating, curtain coating, die coating, or slit coating, and if necessary, placing a protective film on top of it and pressing from above with a roller or the like. The process of heating the impregnated body and drying the solvent contained in the varnish is not particularly limited, but examples of the process include a batch method in which the impregnated body is dried in air or nitrogen using a blower dryer, or a continuous method in which the body is dried by passing through a heating furnace. After the varnish is impregnated into the sheet-like fiber substrate, the resulting impregnated body is heated to a predetermined temperature, whereby the solvent contained in the varnish evaporates, and a prepreg is obtained.

[0094] The fibers constituting the sheet-like fiber substrate can be inorganic or organic fibers, and are not particularly limited. For example, organic fibers such as PET (polyethylene terephthalate) fibers, polystyrene fibers, aramid fibers, ultra-high molecular weight polyethylene fibers, polyamide (nylon) fibers, and liquid crystal polyester fibers; inorganic fibers such as glass fibers, carbon fibers, alumina fibers, tungsten fibers, molybdenum fibers, titanium fibers, steel fibers, boron fibers, silicon carbide fibers, and silica fibers; and the like can be mentioned. Among these, at least one type selected from the group consisting of organic fibers and glass fibers is preferred, and at least one type selected from the group consisting of aramid fibers, liquid crystal polyester fibers, and glass fibers is more preferred. Examples of glass fibers include E glass, NE glass, S glass, D glass, H glass, and T glass. The impregnation of the sheet-like fiber substrate with the varnish is carried out, for example, by immersion and coating. The impregnation may be repeated multiple times as necessary. These sheet-like fiber substrates can be used alone or in combination of two or more, and the amount used is appropriately selected as desired, but is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, and for example, 90% by mass or less, preferably 80% by mass or less, more preferably 70% by mass or less in the prepreg or laminate. If it is within this range, the dielectric properties and mechanical strength of the obtained laminate are highly balanced, which is preferable.

[0095] The thickness of the prepreg is appropriately selected depending on the purpose of use, but is, for example, 0.001 mm or more, preferably 0.005 mm or more, more preferably 0.01 mm or more, and is, for example, 10 mm or less, preferably 1 mm or less, more preferably 0.5 mm or less. If it is within this range, the shapeability during lamination and the properties such as the mechanical strength and toughness of the laminate obtained by curing can be fully exhibited, which is preferable.

[0096] [Metal-clad laminate] The laminate according to the present embodiment may be made into a metal-clad laminate by laminating a metal foil on at least one surface of the laminate according to the present embodiment and heat-curing the metal foil by a lamination press or the like. The metal foil may be attached to both surfaces of the laminate. Examples of the metal foil include copper foil, aluminum foil, nickel foil, gold foil, silver foil, stainless steel foil, etc. From the viewpoints of economy, processability, thermal conductivity, and electrical conductivity, electrolytic copper foil is preferred. As a method for producing the metal clad laminate according to this embodiment, various known methods can be applied. For example, a metal clad laminate can be produced by laminating a metal foil on the laminate according to this embodiment and, if necessary, heat curing the laminate by pressing or the like.

[0097] The metal clad laminate of this embodiment uses a cured product obtained by curing the resin composition of this embodiment, and therefore has an excellent balance of performance characteristics such as low dielectric properties, low thermal expansion, and thermal conductivity, which is suitable for printed wiring boards. Therefore, the metal clad laminate according to this embodiment can be suitably used as an insulating layer material for printed wiring boards.

[0098] [Printed wiring board] The cured product obtained by curing the resin composition according to this embodiment has an excellent balance of performance such as low dielectric properties, low thermal expansion, and thermal conductivity, and therefore can be suitably used for printed wiring boards. The method for producing a printed wiring board can be generally known and is not particularly limited. For example, the film or laminate produced by the above-mentioned method is heated and cured by a lamination press or the like to form an electrical insulating layer. Next, a conductor layer is laminated on the obtained electrical insulating layer by a known method to produce a laminate. Thereafter, the conductor layer in the laminate is subjected to circuit processing or the like to obtain a printed wiring board.

[0099] Examples of metals that can be used for the conductor layer include copper, aluminum, nickel, gold, silver, stainless steel, etc. Examples of methods for forming the conductor layer include a method in which the above metals are made into foil or the like and heat-sealed onto the electrical insulating layer, a method in which the above metals are made into foil or the like and attached onto the electrical insulating layer using an adhesive, and a method in which a conductor layer made of the above metals is formed on the electrical insulating layer by a method such as sputtering, vapor deposition, plating, etc. The printed wiring board may be either a single-sided board or a double-sided board.

[0100] Such a printed wiring board can be used as an electronic device by mounting electronic components such as semiconductor elements, etc. Electronic devices can be manufactured based on publicly known information. Examples of such electronic devices include ICT infrastructure equipment such as servers, routers, supercomputers, mainframes, and workstations; antennas such as GPS antennas, antennas for wireless base stations, millimeter-wave antennas, and RFID antennas; communication devices such as mobile phones, smartphones, PHS, PDAs, and tablet terminals; digital devices such as personal computers, televisions, digital cameras, digital video cameras, POS terminals, wearable terminals, and digital media players; on-vehicle electronic devices such as electronic control system devices, on-vehicle communication devices, car navigation devices, millimeter-wave radars, and on-vehicle camera modules; semiconductor testing equipment, high-frequency measuring equipment, and the like.

[0101] [Uses of the cured product] The cured product obtained by curing the resin composition according to this embodiment has a good balance of low dielectric properties, low thermal expansion, and thermal conductivity, and can therefore be used in applications such as optical fibers, optical waveguides, optical disk substrates, optical filters, lenses, optical adhesives, optical filters for PDPs, coating materials for organic EL, base film substrates for solar cells in the aerospace field, coating materials for solar cells and thermal control systems, semiconductor elements, light-emitting diodes, electronic elements such as various memories, hybrid ICs, MCMs, printed wiring boards, prepregs and laminates used to form insulating layers for printed wiring boards, overcoat materials or interlayer insulating materials for display components, substrates for liquid crystal displays and solar cells, medical instruments, automotive components, resin modifiers, transparent substrates for displays, gas barrier coating materials, electric wire coating materials, automotive components, aerospace components, semiconductor process materials, electric wire coating materials, lithium ion battery components, fuel cell components, capacitor films, flexible display components, anchor coating materials, transparent adhesives, and hard coating materials. In particular, the cured product obtained by curing the resin composition according to this embodiment has an improved performance balance of low dielectric properties, low thermal expansion properties, and thermal conductivity, and also has a good balance of performance such as insulating properties and mechanical properties, and therefore can be suitably used for circuit boards, and more suitably used for high frequency applications such as high frequency circuit boards.

[0102] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can also be adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications and improvements that do not impair the effects of the present invention are included in the present invention. EXAMPLES

[0103] Hereinafter, the present embodiment will be described in detail with reference to examples, etc. However, the present embodiment is not limited to the description of these examples.

[0104] (raw materials) Thermosetting cyclic olefin copolymer 1: Synthesis example 1 described below Radical polymerization initiator 1: Dicumyl peroxide, product name: Percumyl D, manufactured by NOF Corporation Antioxidant 1: Phenol-based antioxidant (pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate), product name: Irganox1010, manufactured by BASF) Inorganic filler 1: amorphous silica, product name: ADMAFINE SC2300-SVJ, manufactured by Admatechs, average particle size D 50 : 0.5 μm, average aspect ratio: 1, volume resistivity: 1.0 × 10 14 Exceeds Ω cm Inorganic filler 2: Boron nitride, product name: Denka Boron Nitride GP, manufactured by Denka Co., Ltd., average particle size D 50 : 6μm, average aspect ratio: 46, volume resistivity: 1.0×10 14 Exceeds Ω cm Inorganic filler 3: Modified boron nitride (Synthesis Example 2 described later), average particle size D 50 : 6μm, average aspect ratio: 46, volume resistivity: 1.0×10 14 Exceeds Ω cm Silane coupling agent 1: 7-octenyltrimethoxysilane, product name: KBM-1083, manufactured by Shin-Etsu Chemical Co., Ltd.

[0105] The following raw materials were used for the synthesis of thermosetting cyclic olefin copolymer 1.

[0106] Transition metal compounds (1): It was synthesized according to the method described in Synthesis Example 1 of JP-A-2004-331965.

[0107] [ka]

[0108] Modified methylaluminoxane (MMAO, Tosoh Finechem) Toluene (Fujifilm Wako Pure Chemical Industries: Wako special grade) Bicyclo[2.2.1]-2-heptene (hereinafter referred to as NB) (manufactured by Tokyo Chemical Industry Co., Ltd.) 5-vinyl-2-norbornene (hereinafter referred to as VNB) (Tokyo Chemical Industry Co., Ltd.) Acetone (Fujifilm Wako Pure Chemical Industries: Wako Special Grade) Methanol (Fujifilm Wako Pure Chemical Industries, Ltd.: Wako special grade)

[0109] [Average particle size of inorganic filler D 50 and calculation of average aspect ratio] Average particle size of inorganic filler D 50 was measured by a laser diffraction particle size distribution measurement method in accordance with JIS Z8825:2013. 50 represents the particle size at which the cumulative frequency is 50% in the volume-based cumulative frequency distribution curve. Next, the true density ρ was measured by the pycnometer method in accordance with JIS R1620:1995, and the specific surface area S was measured by the BET specific surface area method in accordance with JIS Z8830:2013. The obtained average particle size D 50 Using the true density ρ and specific surface area S, the thickness t of an average disk-shaped particle was calculated by the following formula (1) assuming that the inorganic filler particles are disk-shaped. Then, the thickness t and the average particle diameter D 50 Ratio of (D 50 The average aspect ratio was calculated from the following formula (2) expressed in terms of aspect ratio (μm / t): Equation (1): Particle thickness t = 2 × D 50 / (S×ρ×D 50 -4) Equation (2): Average aspect ratio = 0.5 × S × ρ × D 50 -2

[0110] [Measurement of the content of each repeating unit in thermosetting cyclic olefin copolymer 1] The contents of repeating units (a), (b) and (c) in the thermosetting cyclic olefin copolymer 1 were measured using a nuclear magnetic resonance apparatus "EXcalibur270" manufactured by JEOL Ltd. under the following conditions. Number of times: 16 to 64 Measurement temperature: room temperature The above measurements were obtained 1 From the H-NMR spectrum, the contents of repeating units (a), (b) and (c) were calculated based on the intensities of the peaks derived from hydrogen directly bonded to the double bond carbon and the peaks derived from other hydrogen.

[0111] [Number average molecular weight (Mn)] The number average molecular weight (Mn) of the polymer dissolved in o-dichlorobenzene was measured by gel permeation chromatography (GPC) under the following conditions, calibrating the molecular weight with monodisperse polystyrene standards (manufactured by Tosoh Corporation). Measurement equipment: Tosoh gel permeation chromatograph HLC-8321 GPC / HT type Data processing software: Waters Empower3 Detector: Tosoh Bryce type double path, dual flow type RI detector (built into the device) Column: Tosoh TSKgel GMH6-HT, TSKgel GMH6-HTL Column temperature: 140℃ Sample concentration: 0.1% (w / v) Injection volume: 400μL Sampling interval: 0.5 seconds Flow rate: 1.0ml / min

[0112] [Synthesis Example 1: Thermosetting Cyclic Olefin Copolymer 1] In a SUS autoclave with a capacity of 1 L that had been thoroughly substituted with nitrogen, 447 mL of toluene, 14.7 mL of VNB, 38.8 mL of a 6.75 M toluene solution of NB, 1.35 mmol of a hexane solution of MMAO in terms of aluminum atoms, and 1488 mL of hydrogen were charged, and then ethylene was introduced into the system until the total pressure reached 0.78 MPa (gauge pressure). Polymerization was initiated by adding 4 μmol of transition metal compound (1) dissolved in toluene. After reacting for 40 minutes at 35°C, 4 μmol of transition metal compound (1) was added, and the process of adding 4 μmol of transition metal compound (1) every 30 minutes was repeated twice, and polymerization was continued for a total of 130 minutes. The polymerization was then stopped by adding a small amount of methanol. After the polymerization was completed, ion-exchanged water was added to the obtained polymer solution and stirred for 1 hour, and then the organic layer was filtered with filter paper. The organic layer was poured into acetone to precipitate the polymer, which was stirred and filtered with filter paper. The obtained polymer was dried under reduced pressure at 80°C for 10 hours to obtain an ethylene / NB / VNB copolymer, which is a thermosetting cyclic olefin copolymer 1. 1 The content of repeating units of the NB-derived structure in the thermosetting cyclic olefin copolymer 1 determined by H-NMR was 34 mol%, the content of repeating units of the VNB-derived structure was 10 mol%, and the number average molecular weight (Mn) calculated by GPC measurement was 7,000.

[0113] [Synthesis Example 2: Inorganic Filler 3 (Modified Boron Nitride)] 10.0 g of inorganic filler 2 powder was dispersed in 70 ml of toluene in a two-neck flask and heated and stirred at 80°C for 10 minutes. A diluted solution of 10 g of silane coupling agent 1 dissolved in 10 ml of toluene was dropped into the dispersion over 10 minutes using a dropping funnel. The dispersion was heated and stirred at 80°C for 3 hours, and then cooled to room temperature with water. The dispersion was filtered by suction, and the filtrate was washed three times with toluene and then three times with acetone to obtain modified boron nitride. The obtained modified boron nitride was dried under reduced pressure at 80°C for 1 hour.

[0114] [Example 1] (Preparation of Varnish) The thermosetting cyclic olefin copolymer 1 obtained in Synthesis Example 1 and other materials were weighed according to the composition in Table 1. The weighed sample was stirred in toluene until it was sufficiently dissolved to obtain a varnish. The unit of the blending ratio of each raw material in Table 1 is parts by mass.

[0115] (Preparation of thermosetting film) The obtained varnish was applied to a release-treated PET film at a speed of 10 mm / sec under the condition of an applicator gap of 200 μm using an automatic film coater (Tester Sangyo Co., Ltd., PI-1210), and then dried at 150° C. for 4 minutes under a nitrogen stream (30 L / min) using a blower dryer (Espec Corp., STPH-102M), and the PET film was peeled off. Two of the obtained films were stacked, and pressurized to 3.5 MPa with a vacuum degree of 1.2 kPa or less using a vacuum press, and the temperature was raised at a constant rate from room temperature (25° C.), and held at 180° C. for 120 minutes to obtain a thermosetting film. The film thickness was adjusted to about 50 μm.

[0116] [Examples 2 to 3 and Comparative Examples 1 to 4] A varnish and a thermoset film were prepared in the same manner as in Example 1, except that the resin composition was formulated according to the formulation in Table 1.

[0117] The dielectric loss tangent Df, coefficient of linear expansion CTE, and thermal conductivity of the obtained thermoset film were evaluated according to the following methods. The results are shown in Table 1.

[0118] [Dielectric loss tangent Df] The thermosetting film of each example was cut into a test piece having a length of 50 mm, a width of 50 mm, and a thickness of about 50 μm. The dielectric loss tangent Df of the obtained test piece was then measured at 23±2°C, 50±5% RH, and 10 GHz by a cylindrical cavity resonator method using a cylindrical cavity resonator (YHP's Synthesized Sweeper 8340B and YHP's Network Analyzer 8510B). A dielectric tangent Df of 0.0010 or less was deemed to be acceptable.

[0119] [Coefficient of linear expansion CTE] For the thermoset film of each example, the coefficient of linear expansion CTE was measured as follows. The thermosetting film was cut into a test piece having a length of 20 mm, a width of 4 mm, and a thickness of about 50 μm. The obtained test piece was then measured using a thermomechanical analyzer (Hitachi High-Tech Corporation, TMA7100C) under the following conditions: a measurement temperature range of 5 to 300°C, a heating rate of 5°C / min, a test load of 5 kgf, in a nitrogen atmosphere, and in film stretching mode. From the measurement results, the linear expansion coefficient CTE at 25 to 90°C was calculated. The linear expansion coefficient CTE is expressed in ppm / K. A linear expansion coefficient of 50 ppm / K or less was considered acceptable.

[0120] [Thermal conductivity (in-plane and thickness directions)] A test piece measuring 30 mm in length, 5 mm in width, and approximately 50 μm in thickness was cut out from the thermosetting film of each example. The thermal diffusivity of the obtained test piece at 23°C was then measured. In addition, 10 test pieces measuring 6 mm in diameter, 50 μm in thickness were stacked together to measure the specific heat capacity. Furthermore, the density was measured using a test piece measuring 50 mm in length, 50 mm in width, and approximately 50 μm in thickness, and the thermal conductivity in the in-plane direction and the thickness direction was calculated using the following formula (3). Equation (3): Thermal conductivity (κ) = thermal diffusivity (α) × specific heat capacity (Cp) × density (ρ) The thermal diffusivity in the in-plane direction of the thermosetting film was measured by an optical alternating current method, the thermal diffusivity in the thickness direction of the thermosetting film was measured by a temperature wave thermal analysis method, and the specific heat was measured by a differential scanning calorimetry method. The thermal conductivity in the in-plane direction was 1.0 W / (m K) or more, and the thermal conductivity in the thickness direction was 0.20 W / (m K) or more.

[0121] [Table 1]

Claims

1. A resin composition comprising a thermosetting cyclic olefin copolymer (A) having a crosslinkable group, a radical polymerization initiator (B), an antioxidant (C), and an inorganic filler (D), The inorganic filler (D) comprises a plate-like inorganic filler (D1) having an average aspect ratio of 2 or more and 170 or less, The resin composition, wherein the content of the inorganic filler (D1) is 30 parts by mass or more and 300 parts by mass or less per 100 parts by mass of the thermosetting cyclic olefin copolymer (A).

2. The inorganic filler (D1) has a volume resistivity of 1.0 × 10 at 23°C. ８ The resin composition according to claim 1, having a modulus of elasticity of Ω·cm or more.

3. The volume-based average particle diameter D of the inorganic filler (D1) measured by a laser diffraction particle size distribution measurement method ５０ The resin composition according to claim 1 or 2, wherein the particle size is 0.1 μm or more and 30.0 μm or less.

4. 3. The resin composition according to claim 1, wherein the inorganic filler (D1) comprises at least one selected from the group consisting of boron nitride, talc, mica, clay, glass flake, calcium carbonate, alumina, wollastonite, sericite, hydrotalcite, montmorillonite, and insulating graphite.

5. The resin composition according to claim 1 or 2, wherein the inorganic filler (D1) contains boron nitride.

6. The resin composition according to claim 1 or 2, wherein the inorganic filler (D1) is surface-treated with a silane coupling agent.

7. The resin composition according to claim 6 , wherein the silane coupling agent comprises a silane coupling agent having a vinyl group.

8. 3. The resin composition according to claim 1, wherein a total content of the thermosetting cyclic olefin copolymer (A), the radical polymerization initiator (B), the antioxidant (C), and the inorganic filler (D) is 50% by mass or more and 100% by mass or less, when a total amount of solids in the resin composition is 100% by mass.

9. 3. The resin composition according to claim 1, wherein the thermosetting cyclic olefin copolymer (A) comprises one or more olefin-derived repeating units (a) represented by the following formula (I), one or more cyclic non-conjugated diene-derived repeating units (b) represented by the following formula (III), and one or more cyclic olefin-derived repeating units (c) represented by the following formula (V): 【Chemistry 1】 In the formula (I), R ３００ represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms. 【Chemistry 2】 In the formula (III), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, and R ６１ ~R ７６ and R ａ１ and R ｂ１ may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R １０４ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, t is a positive integer of 0 to 10, and R ７５ and R ７６ may be bonded to each other to form a monocyclic or polycyclic ring. 【Transformation 3】 In the above formula (V), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, and R ６１ ~R ７８ and R ａ１ and R ｂ１ may be the same or different and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a halogenated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms; R ７５ ~R ７８ may be bonded to each other to form a monocyclic or polycyclic ring.

10. 3. The resin composition according to claim 1, wherein, when the total number of moles of repeating units in the thermosetting cyclic olefin copolymer (A) is taken as 100 mol%, the content of the olefin-derived repeating unit (a) is 10 mol% or more and 80 mol% or less, the content of the cyclic non-conjugated diene-derived repeating unit (b) is 1 mol% or more and 40 mol% or less, and the content of the cyclic olefin-derived repeating unit (c) is 4 mol% or more and 60 mol% or less.

11. A varnish comprising the resin composition of claim 1 or 2 and a solvent.

12. A film comprising a cured product obtained by curing the resin composition according to claim 1 or 2.

13. A laminate comprising the film of claim 12.

14. A metal clad laminate comprising a metal foil on at least one surface of the laminate of claim 13.

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