WO2025187203A1 - Resin composition, varnish, prepreg, film, laminate, metal-clad laminate, printed wiring board, and electronic device - Google Patents

Abstract

Disclosed is a resin composition which contains a thermosetting cyclic olefin (co)polymer (m) that has a crosslinkable group (α), and a radical initiator (A), wherein the radical initiator (A) contains a compound represented by general formula (1). (In general formula (1), R₁ to R₁₀ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1-20 carbon atoms, a cycloalkyl group having 3-20 carbon atoms, an aromatic hydrocarbon group having 6-20 carbon atoms, or a halogenated alkyl group having 1-20 carbon atoms, R₁₁ to R₁₄ are each independently an alkyl group having 1-20 carbon atoms, a cycloalkyl group having 3-20 carbon atoms, an aromatic hydrocarbon group having 6-20 carbon atoms, or a halogenated alkyl group having 1-20 carbon atoms, and at least one of R₁₁ to R₁₄ is independently an alkyl group having 2-20 carbon atoms, a cycloalkyl group having 3-20 carbon atoms, an aromatic hydrocarbon group having 6-20 carbon atoms, or a halogenated alkyl group having 1-20 carbon atoms.)

Description

Resin composition, varnish, prepreg, film, laminate, metal clad laminate, printed wiring board and electronic device

The present invention relates to resin compositions, varnishes, prepregs, films, laminates, metal-clad laminates, printed wiring boards, and electronic devices.

In recent years, in addition to an increase in wireless communication devices that use high-frequency bands, faster communication speeds have inevitably led to increased use of higher frequency bands. Accordingly, in order to minimize transmission loss at high frequencies, materials that make up printed wiring boards are also required to have a low dielectric dissipation factor.

Patent Document 1 describes a cyclic olefin copolymer having a crosslinkable group from which a crosslinked product having excellent stability over time of dielectric properties and heat resistance, as well as excellent transparency, mechanical properties, dielectric properties, and gas barrier properties can be obtained, and further describes a crosslinked product having excellent properties, the copolymer comprising (A) one or more olefin-derived repeating units represented by a specific chemical formula (I), (B) a cyclic non-conjugated diene-derived repeating unit represented by a specific chemical formula (III), and (C) one or more cyclic olefin-derived repeating units represented by a specific chemical formula (V), wherein the repeating units (B) derived from a cyclic non-conjugated diene account for 19 mol % to 36 mol % when the total number of moles of the repeating units is taken as 100 mol %.
Patent Document 1 describes that the invention described in Patent Document 1 aims to provide a cyclic olefin copolymer having a crosslinkable group, which can give a crosslinked product that is excellent in stability over time of dielectric properties and heat resistance, and is also excellent in transparency, mechanical properties, dielectric properties, and gas barrier properties, and further provides a crosslinked product that is excellent in the above properties.

Patent Document 2 also describes a resin composition that can be used as a circuit board material to obtain an interlayer insulating film (also referred to as an interlayer insulating layer in the circuit board) for a circuit board intended for a highly integrated arithmetic device, and a crosslinked body that is excellent in dielectric properties, heat resistance, and mechanical properties in a high frequency range, and is suitable for circuit boards and the like, and that provides a cyclic olefin copolymer resin composition containing a cyclic olefin copolymer (M) and a maleimide compound (L), wherein the cyclic olefin copolymer (M) contains a cyclic olefin copolymer (m) that contains one or more olefin-derived repeating units represented by a specific chemical formula (I), one or more cyclic non-conjugated diene-derived repeating units represented by a specific chemical formula (III), and one or more cyclic olefin-derived repeating units represented by a specific chemical formula (V), and the maleimide compound (L) has a solubility parameter (SP value) determined by the Fedors method of 19 J ^1/2 /cm ^3/2 or more, and 26 J ^1/2 /cm 3/2 or more. and a maleimide compound (l) which is a bismaleimide compound having at least two maleimide groups in the ^molecule , wherein the content of the maleimide compound (L) is 1 part by mass or more and 50 parts by mass or less when the total amount of the cyclic olefin copolymer (M) and the maleimide compound (L) is 100 parts by mass.
Patent Document 2 states that the invention described in Patent Document 2 provides a resin composition that can be used as a circuit board material to obtain an interlayer insulating film (also called an interlayer insulating layer in a circuit board) for a circuit board intended for a highly integrated arithmetic device, and a crosslinked body that has excellent dielectric properties, heat resistance, and mechanical properties in the high frequency range, suitable for circuit boards, etc.

International Publication No. 2012/046443 International Publication No. 2020/110958

The present invention provides a resin composition that can produce a cured product with an improved balance of low dielectric properties and heat resistance in the high-frequency range at a crosslinking temperature of 200°C or less.

The present invention is as follows.
1. A resin composition comprising a thermosetting cyclic olefin (co)polymer (m) having a crosslinkable group (α) and a radical initiator (A),
The resin composition, wherein the radical initiator (A) contains a compound represented by the following general formula (1):
[In general formula (1), R ₁ to R ₁₀ are each independently a hydrogen atom, a halogen atom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms; R ₁₁ to R ₁₄ are each independently an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms; and at least one of R ₁₁ to R ₁₄ is each independently an alkyl group having from 2 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms]
2. The resin composition according to 1., wherein in the general formula (1), R ₁ to R ₁₀ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms.
3. The resin composition according to 2., wherein in the general formula (1), R ₁ to R ₁₀ are hydrogen atoms.
4. The resin composition according to any one of 1. to 3., wherein in general formula (1), R ₁₁ to R ₁₄ each independently represent an alkyl group having 2 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or a halogenated alkyl group having 1 to 20 carbon atoms.
5. The resin composition according to 4., wherein in the general formula (1), R ₁₁ to R ₁₄ each independently represent an alkyl group having 2 to 20 carbon atoms.
6. The resin composition according to 5., wherein in the general formula (1), R ₁₁ to R ₁₄ are ethyl groups.
7. The resin composition according to any one of 1. to 6., wherein the content of the radical initiator (A) in the resin composition is 0.02 parts by mass or more and 20.0 parts by mass or less per 100 parts by mass of the thermosetting cyclic olefin (co)polymer (m).
8. The thermosetting cyclic olefin (co)polymer (m) is
(A) one or more olefin-derived repeating units represented by the following general formula (I),
(B) one or more repeating units derived from a cyclic non-conjugated diene represented by the following general formula (III),
(C) one or more repeating units derived from cyclic olefins represented by the following general formula (V):
[In the above general formula (I), R ³⁰⁰ represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms.]
[In the above general formula (III), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, R ⁶¹ to R ⁷⁶ , R ^a1 and R ^b1 may be the same or different and represent 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 monocycle or polycycle.]
[In the above general formula (V), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, R ⁶¹ to R ⁷⁸ , R ^a1 and R ^b1 may be the same or different and represent 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, and R ⁷⁵ to R ⁷⁸ may be bonded to each other to form a monocycle or polycycle.]
9. When the total number of moles of repeating units in the thermosetting cyclic olefin (co)polymer (m) is taken as 100 mol%,
the content of the olefin-derived repeating unit (A) is 10 mol% or more and 90 mol% or less;
8. The resin composition according to 8., wherein the content of the repeating unit (B) derived from the cyclic non-conjugated diene is 1 mol % or more and 40 mol % or less, and the content of the repeating unit (C) derived from the cyclic olefin is 1 mol % or more and 50 mol % or less.
10. The resin composition according to 8. or 9., wherein the cyclic non-conjugated diene constituting the repeating unit (B) derived from the cyclic non-conjugated diene includes 5-vinyl-2-norbornene.
11. The ^resin composition according to any one of 8. to 10., wherein the cyclic olefin constituting the cyclic olefin-derived repeating unit (C) includes at least one selected from the group consisting of tetracyclo[ ^{4.4.0.12,5.17,10} ]-3-dodecene and bicyclo[2.2.1]-2-heptene.
12. The resin composition according to any one of 1. to 11., further comprising an antioxidant (B).
13. The resin composition according to any one of 1. to 12., wherein a cured product obtained by heating the resin composition at 200°C has a dielectric loss tangent at 10 GHz of less than 0.0020.
14. The resin composition according to any one of 1. to 13., wherein ΔTg represented by the following formula (10) is 30° C. or higher:
ΔTg=Tg ₁ - Tg ₀ (10)
(In formula (10), Tg ₀ is the glass transition temperature of the thermosetting cyclic olefin (co)polymer (m), and Tg ₁ is the glass transition temperature of the cured product obtained by heating the resin composition at 200°C.)
15. A varnish comprising the resin composition according to any one of 1. to 14. and a solvent.
16. A prepreg obtained by impregnating a fiber substrate with the resin composition according to any one of 1. to 14. or the varnish according to 15.
17. A film comprising a cured product of the resin composition according to any one of 1. to 14.
18. A laminate comprising the prepreg according to 16. or the film according to 17.
19. A metal clad laminate comprising the laminate according to 18. above and a metal foil on at least one surface thereof.
20. A printed wiring board manufactured using the prepreg according to 16. or the metal clad laminate according to 19.
21. An electronic device comprising the film according to 17. or the printed wiring board according to 20.
22. The electronic device of claim 21, wherein the electronic device includes a high-speed communication-enabled module.

The present invention provides a resin composition that can produce a cured product with an improved balance of low dielectric properties and heat resistance in the high-frequency range at a crosslinking temperature of 200°C or less.

Hereinafter, the present invention will be described based on the embodiments. In the present embodiments, "A to B" indicating a range of values means A or more and B or less unless otherwise specified.
In addition, in this specification, the term "cyclic olefin (co)polymer" means at least one polymer selected from the group consisting of a homopolymer of a cyclic olefin and a copolymer of a cyclic olefin and a monomer component other than the cyclic olefin.
Each monomer constituting the thermosetting cyclic olefin (co)polymer (m) according to the present invention may be a monomer obtained from a fossil raw material, a monomer obtained from an animal or plant raw material, or a monomer derived from biomass.
In addition, in this embodiment, —CH═CH ₂ in the (meth)acrylic group is not included in the vinyl group.

1. Resin Composition The resin composition of this embodiment will be described below.

The resin composition of this embodiment is a resin composition containing a thermosetting cyclic olefin (co)polymer (m) having a crosslinkable group (α) and a radical initiator (A), where the radical initiator (A) contains a compound represented by the following general formula (1):

In general formula (1), R ₁ to R ₁₀ are each independently a hydrogen atom, a halogen atom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms; R ₁₁ to R ₁₄ are each independently an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms; and at least one of R ₁₁ to R ₁₄ is each independently an alkyl group having from 2 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms.

According to the inventors' investigations, creating the cured product described in Patent Document 1 requires crosslinking at temperatures above 200°C, and there was room for improvement at crosslinking temperatures below 200°C. After extensive investigations, the inventors discovered that by using a resin composition that combines a specific radical initiator with a thermosetting cyclic olefin (co)polymer, it is possible to obtain a cured product with an improved balance of low dielectric properties and heat resistance in the high frequency range, even at crosslinking temperatures below 200°C, and thus completed the present invention.

The components contained in the resin composition of this embodiment are described below.

[Radical initiator (A)]
The radical initiator (A) contained in the resin composition of the present embodiment will be described below.

In general formula (1), from the viewpoint of being able to obtain a cured product having an even better balance between low dielectric properties and heat resistance in the high-frequency range at a crosslinking temperature of 200°C or less, _R1 to _R10 are preferably each independently a hydrogen atom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, or an aromatic hydrocarbon group having from 6 to 20 carbon atoms, and more preferably a hydrogen atom.

In general formula (1), from the viewpoint of being able to obtain a cured product having an even better balance between low dielectric properties and heat resistance in the high frequency range at a crosslinking temperature of 200°C or less, R ₁₁ to _R 14 are preferably each independently an alkyl group having from 2 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms, more preferably each independently an alkyl group having from 2 to 20 carbon atoms, and even more preferably an ethyl group.
An example of the radical initiator (A) is DEDPH (2,3-diethyl-2,3-diphenylhexane, manufactured by Fluorochem, in which R ₁ to R ₁₀ are hydrogen atoms and R ₁₁ to R ₁₄ are ethyl groups in general formula (1)).

The content of the radical initiator (A) in the resin composition is preferably 0.02 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, even more preferably 0.5 parts by mass or more, even more preferably 1.0 parts by mass or more, even more preferably 1.5 parts by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 2.1 parts by mass or more, even more preferably 2.5 parts by mass or more, even more preferably 3.0 parts by mass or more, even more preferably 3.5 parts by mass or more, even more preferably 4.0 parts by mass or more, and even more preferably 4.2 parts by mass or more, relative to 100 parts by mass of the thermosetting cyclic olefin (co)polymer (m), from the viewpoint of obtaining a cured product with an even better balance of low dielectric properties and heat resistance in the high-frequency range at a crosslinking temperature of 200°C or less; and from the viewpoint of further improving the dielectric properties of the cured product, it is preferably 20.0 parts by mass or less, more preferably 10.0 parts by mass or less, even more preferably 5.0 parts by mass or less, and from the viewpoint of being able to obtain a cured product with an even better balance of low dielectric properties and heat resistance in the high-frequency range at a crosslinking temperature of 200°C or less, the amount is preferably 0.02 to 20.0 parts by mass, more preferably 0.05 to 20.0 parts by mass, even more preferably 0.1 to 20.0 parts by mass, even more preferably 0.5 to 20.0 parts by mass, even more preferably 1.0 to 10.0 parts by mass, even more preferably 1.5 to 10.0 parts by mass, even more preferably 2.0 to 10.0 parts by mass, even more preferably 2.1 to 10.0 parts by mass, even more preferably 2.5 to 5.0 parts by mass, even more preferably 3.0 to 5.0 parts by mass, even more preferably 3.5 to 5.0 parts by mass, even more preferably 4.0 to 5.0 parts by mass, and even more preferably 4.2 to 5.0 parts by mass.

[Thermosetting Cyclic Olefin (Co)polymer (m) Having Crosslinking Group (α)]
The resin composition of the present embodiment contains a thermosetting cyclic olefin (co)polymer (m) having a crosslinkable group (α) (hereinafter also simply referred to as “cyclic olefin (co)polymer (m)”).
The cyclic olefin (co)polymer (m) can be used without any particular limitation as long as it is a thermosetting cyclic olefin (co)polymer containing a repeating unit derived from a cyclic olefin, and may be, for example, a ring-opening polymer of a cyclic olefin or an addition polymer of a monomer such as an α-olefin and a cyclic olefin.
In addition, the cyclic olefin (co)polymer (m) has a crosslinkable group (α), which is a functional group that can be used in a crosslinking reaction, from the viewpoint of improving the heat resistance of the cured product obtained by forming a crosslinked structure. Examples of the crosslinkable group (α) include crosslinkable functional groups such as a vinyl group; a vinylidene group; a vinylene group; a vinyl group substituted with an alkyl group, a phenyl group, or an alkylphenyl group; a vinylidene group substituted with an alkyl group, a phenyl group, or an alkylphenyl group; a vinylene group substituted with an alkyl group, a phenyl group, or an alkylphenyl group; a maleimide group; a thiol group; a thienyl group; a silyl group; an epoxy group; an oxazoline group; a (meth)acrylic group; and a carboxyl group, and preferably a vinyl group. By having the crosslinkable group (α), the cyclic olefin (co)polymer (m) can form a crosslinked structure with the crosslinking aid (A) described below, and can further improve low thermal expansion. The cyclic olefin (co)polymer (m) may have one or more crosslinkable groups (α) in one molecule, and when the cyclic olefin (co)polymer (m) has multiple crosslinkable groups (α) in one molecule, they may have one type or two or more types.

The content of the thermosetting cyclic olefin (co)polymer (m) in the resin composition of this embodiment is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, even more preferably 95 parts by mass or more, and for example, 99 parts by mass or less, per 100 parts by mass of the resin composition of this embodiment, from the viewpoint of being able to obtain a cured product with an even better balance of low dielectric properties and heat resistance in the high-frequency range at a crosslinking temperature of 200°C or less.

The cyclic olefin (co)polymer (m) of this embodiment preferably contains (A) repeating units derived from one or more olefins represented by the following general formula (I), (B) repeating units derived from one or more cyclic non-conjugated dienes represented by the following general formula (III), and (C) repeating units derived from one or more cyclic olefins represented by the following general formula (V):

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

In the above general 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 to R ⁷⁶ as well as R ^a1 and R ^b1 may be the same or different from one another and are each 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 monocycle or polycycle.

In the above general formula (V), 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 to R ⁷⁸ as well as R ^a1 and R ^b1 may be the same or different and are each 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, and R ⁷⁵ to R ⁷⁸ may be bonded to each other to form a monocycle or polycycle.

When the cyclic olefin (co)polymer (m) is a (co)polymer (m) containing the repeating units (A) to (C), when the total number of moles of repeating units in the thermosetting cyclic olefin (co)polymer (m) is taken as 100 mol%, the content of the olefin-derived repeating unit (A) is preferably 10 mol% or more and 90 mol% or less, more preferably 20 mol% or more and 85 mol% or less, even more preferably 30 mol% or more and 80 mol% or less, even more preferably 40 mol% or more and 70 mol% or less, even more preferably 50 mol% or more and 70 mol% or less, and even more preferably 55 mol% or more and 65 mol% or less, and the content of the cyclic non-conjugated diene-derived repeating unit (B) is preferably 1 mol% or more and 40 mol% or less, more preferably The content of the repeating unit (C) derived from a cyclic olefin is preferably 1 mol% or more and 50 mol% or less, more preferably 3 mol% or more and 40 mol% or less, more preferably 10 mol% or more and 35 mol% or less, even more preferably 7 mol% or more and 30 mol% or less, even more preferably 15 mol% or more and 30 mol% or less, and even more preferably 20 mol% or more and 30 mol% or less, and the content of the repeating unit (C) derived from a cyclic olefin is preferably 1 mol% or more and 50 mol% or less, more preferably 3 mol% or more and 40 mol% or less, even more preferably 10 mol% or more and 35 mol% or less, even more preferably 10 mol% or more and 30 mol% or less, even more preferably 10 mol% or more and 25 mol% or less, even more preferably 10 mol% or more and 20 mol% or less, and even more preferably 10 mol% or more and 15 mol% or less.
When the content of each repeating unit in the cyclic olefin (co)polymer (m) is within the above range, the cured product obtained from the resin composition can have improved dielectric properties and heat resistance, and can have an improved balance of mechanical properties, dielectric properties, transparency, and gas barrier properties.

The olefin monomer that can be one of the copolymerization raw materials for the cyclic olefin (co)polymer (m) is a monomer that undergoes addition copolymerization to give the skeleton represented by formula (I) above, and can be an olefin represented by the following general formula (Ia):

In the above general 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 general 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. From the viewpoint of obtaining a cured product having better heat resistance, mechanical properties, dielectric properties, transparency, and gas barrier properties, among these, one or two types selected from the group consisting of ethylene and propylene are preferred, and ethylene is more preferred. Two or more types of olefin monomers represented by the above formula (Ia) may be used.

A cyclic non-conjugated diene monomer, which may be one of the copolymerization raw materials for the cyclic olefin (co)polymer (m), can be addition copolymerized to form a structural unit represented by the above formula (III). Specifically, a cyclic non-conjugated diene represented by the following general formula (IIIa), which corresponds to the above general formula (III), can be used.

In the above general formula (IIIa), 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 to R ⁷⁶ as well as R ^a1 and R ^b1 may be the same or different from one another and are each 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 monocycle or polycycle.

The cyclic non-conjugated diene represented by the general formula (IIIa) is not limited to, but examples thereof include cyclic non-conjugated dienes represented by the following chemical formula: Of these, the cyclic non-conjugated diene represented by the general formula (IIIa), i.e., the cyclic non-conjugated diene constituting the repeating unit (B) derived from a cyclic non-conjugated diene, preferably contains at least one selected from the group consisting of 5-vinyl-2-norbornene and 8-vinyl-9-methyltetracyclo[ ^{4.4.0.12,5.17,10} ]-3- ^dodecene , more preferably contains 5-vinyl-2-norbornene.

The cyclic non-conjugated diene represented by the above general formula (IIIa) can also be specifically represented by the following general formula (IIIb):

In general formula (IIIb), n is an integer of 0 to 10, R ₁ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ₂ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

When the cyclic olefin (co)polymer (m) of this embodiment contains a structural unit derived from a cyclic non-conjugated diene represented by general formula (III), it has a double bond in the side chain portion, i.e., in a portion other than the main chain of the copolymer. The functional group containing the double bond can be one of the crosslinkable groups (α) described above.

A cyclic olefin monomer, which can be one of the copolymerization raw materials for the cyclic olefin (co)polymer (m), can be addition copolymerized to form a structural unit represented by the above formula (V). Specifically, a cyclic olefin monomer represented by the following general formula (Va), which corresponds to the above general formula (V), can be used.

In the above general formula (Va), 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 to R ⁷⁸ as well as R ^a1 and R ^b1 may be the same or different and are each 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, and R ⁷⁵ to R ⁷⁸ may be bonded to each other to form a monocycle or polycycle.

Specific examples of the cyclic olefin represented by the general formula (Va) include the compounds described in WO 2006/118261.
The cyclic olefin represented by the general formula (Va), i.e., the cyclic olefin constituting the cyclic olefin-derived repeating unit (C), preferably includes at least one selected from the group consisting of bicyclo[2.2.1]-2-heptene (also called norbornene) and tetracyclo[ ^{4.4.0.12,5.17,10} ]-3- ^dodecene (also called tetracyclododecene). These cyclic olefins have a rigid ring structure, which makes it easy to maintain the elastic modulus of the cured product made from the cyclic olefin (co)polymer (m) and the resin composition, and also has the advantage of being easy to control crosslinking because they do not include a heterogeneous double bond structure.

By using the olefin monomer represented by the aforementioned general formula (Ia) and the cyclic olefin represented by the general formula (Va) as copolymerization components, the solubility of the cyclic olefin (co)polymer (m) in solvents is further improved, resulting in better moldability and improved product yield.

The cyclic olefin (co)polymer (m) may be composed of (A) repeating units derived from one or more olefins represented by general formula (I), (B) repeating units derived from a cyclic non-conjugated diene represented by general formula (III), and (C) repeating units derived from one or more cyclic olefins represented by general formula (V), as well as repeating units derived from a cyclic olefin other than the cyclic non-conjugated diene represented by general formula (III) and the cyclic olefin represented by general formula (V), and/or a chain polyene.
In this case, as copolymerization raw materials for the cyclic olefin (co)polymer (m), in addition to the olefin monomer represented by the general formula (Ia), the cyclic non-conjugated diene monomer represented by the general formula (IIIa), and the cyclic olefin monomer represented by the general formula (Va), a cyclic olefin monomer other than the cyclic non-conjugated diene monomer represented by the general formula (IIIa) and the cyclic olefin monomer represented by the general formula (Va), and/or a chain polyene monomer can be used.
As such a cyclic olefin monomer and a chain polyene monomer, a cyclic olefin represented by the following general formula (VIa) or (VIIa) or a chain polyene represented by the following general formula (VIIIa) can be used. Two or more different types of these cyclic olefins and chain polyenes may be used.

In general 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; R ⁸¹ to R ⁹⁹ may be the same or different and represent 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 or an alkoxy group having 6 to 20 carbon atoms; the carbon atom to which R ⁸⁹ and R ⁹⁰ are bonded may be bonded to the carbon atom to which R ⁹³ is bonded or the carbon atom to which R ⁹¹ is bonded 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.

In general 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 in the range of 1≦f≦18.

In general formula (VIIIa), R ²⁰¹ to R ²⁰⁶ may be the same or different and each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and P represents a linear or branched hydrocarbon group having 1 to 20 carbon atoms, which may contain a double bond and/or a triple bond.

Specific examples of cyclic olefins represented by general formula (VIa) and general formula (VIIa) include the compounds described in paragraphs 0037 to 0063 of WO 2006/118261.

Specific examples of linear polyenes represented by general 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, and 1,5-hexadiene. Cyclizable polyenes cyclized from polyenes such as 1,3-butadiene and 1,5-hexadiene may also be used.

When the cyclic olefin (co)polymer (m) contains a structural unit derived from a chain polyene represented by the above general formula (VIIIa), or a structural unit derived from a cyclic non-conjugated diene represented by the general formula (III) and a cyclic olefin other than the cyclic olefin represented by the general formula (V) [for example, general formula (VIa) or general formula (VIIa)], the content of such structural units is preferably 0.1 to 100 mol %, more preferably 0.1 to 50 mol %, based on the total number of moles of repeating units derived from one or more olefins represented by the above general formula (I), repeating units derived from one or more cyclic non-conjugated dienes represented by the above general formula (III), and repeating units derived from one or more cyclic olefins represented by the above general formula (V).

By using the olefin monomer represented by the aforementioned general formula (I), the cyclic olefin represented by the general formula (VIa) or (VIIa), and the linear polyene represented by the general formula (VIIIa) as copolymerization components, the solubility of the cyclic olefin (co)polymer (m) in solvents is further improved, resulting in better moldability and improved product yield. Of these, the cyclic olefin represented by the general formula (VIa) or (VIIa) is preferred. These cyclic olefins have a rigid ring structure, which makes it easier to maintain the elastic modulus of the cured product made from the cyclic olefin (co)polymer (m) and resin composition, and they also have the advantage of not containing heterogeneous double bond structures, making it easier to control crosslinking.

The comonomer content and glass transition temperature (Tg) of the cyclic olefin (co)polymer (m) can be controlled by adjusting the monomer charging ratio depending on the intended use. The Tg of the cyclic olefin (co)polymer (m) is, for example, 300°C or less, preferably 250°C or less, more preferably 200°C or less, even more preferably 170°C or less, even more preferably 150°C or less, even more preferably 120°C or less, and even more preferably 110°C or less. When the Tg is equal to or less than the upper limit, the melt moldability of the cyclic olefin (co)polymer (m) and its solubility in solvents when made into a varnish are improved.
The lower limit of the Tg of the cyclic olefin (co)polymer (m) is not particularly limited, but is, for example, 50°C or higher, or may be 70°C or higher, or may be 90°C or higher.

The number average molecular weight (Mn) of the cyclic olefin (co)polymer (m) measured by gel permeation chromatography in terms of polystyrene is preferably 5,000 or more, more preferably 10,000 or more, even more preferably 15,000 or more, and even more preferably 20,000 or more, from the viewpoint of further improving the performance balance of dielectric properties, low thermal expansion, and mechanical properties; and 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, it 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 25,000 or less.
The number average molecular weight (Mn) of the cyclic olefin (co)polymer (m) can be controlled by the polymerization conditions such as the polymerization catalyst, co-catalyst, amount of _H2 added, and polymerization temperature.

The cyclic olefin (co)polymer (m) of 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.

[Crosslinking aid]
The resin composition of the present embodiment preferably further contains a crosslinking aid.

The crosslinking aid contained in the resin composition of this embodiment preferably includes a crosslinking compound (a) having three or more crosslinking groups (β). The crosslinking groups (β) preferably include at least one functional group selected from the group consisting of a vinyl group and an allyl group.

The crosslinkable compound (a) preferably has three or more crosslinkable groups (β) in order to further improve the balance of low dielectric constant, crosslinkability, and heat resistance in the high frequency range. The number of crosslinkable groups (β) is not particularly limited, but may be, for example, 10 or less, 8 or less, 6 or less, or 4 or less.

Furthermore, from the viewpoint of further improving the performance balance of low dielectric constant, crosslinkability, and heat resistance in the high frequency range, the crosslinkable compound (a) preferably further has a heterocyclic structure, more preferably has a nitrogen-containing heterocyclic ring, and even more preferably has one or more ring structures selected from the group consisting of an isocyanuric ring structure and a glycoluril ring structure.

The crosslinking aid contained in the resin composition of this embodiment includes one or more compounds selected from the group consisting of glycoluril-based crosslinking compounds, bisisocyanurate-based crosslinking compounds, and isocyanurate-based crosslinking compounds, from the viewpoint of further improving the performance balance of low dielectric properties, crosslinkability, and heat resistance in the high-frequency range.

The glycoluril-based crosslinkable compound of this embodiment preferably includes a compound represented by the following formula (1). The bisisocyanurate-based crosslinkable compound and isocyanurate-based crosslinkable compound of this embodiment preferably include a compound represented by the following formula (2-a).

In formula (1), at least three of R ¹ to R ⁴ are organic groups containing a vinyl group and having 1 to 10 carbon atoms or organic groups containing an allyl group and having 1 to 10 carbon atoms, preferably at least three of R ¹ to R ⁴ are organic groups containing a vinyl group and having 1 to 5 carbon atoms or organic groups containing an allyl group and having 1 to 5 carbon atoms, more preferably at least three of R ¹ to R ⁴ are vinyl groups or allyl groups, even more preferably all of R ¹ to R ⁴ are vinyl groups or allyl groups, and even more preferably all of R ¹ to R ⁴ are allyl groups. Furthermore, R ¹ to R ⁴ may be, for example, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group.
Each X is independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group, and is preferably a hydrogen atom.

In formula (2-a), X ¹ to X ³ are each independently a hydrogen atom, an alkyl group having from 1 to 10 carbon atoms, a vinyl group, an allyl group, or an organic group represented by formula (2-b), and in formulas (2-a) and (2-b), at least three of X ¹ to X ⁵ are organic groups having from 1 to 10 carbon atoms and containing a vinyl group, or organic groups having from 1 to 10 carbon atoms and containing an allyl group, preferably at least three of X ¹ to X ⁵ are organic groups having from 1 to 5 carbon atoms and containing a vinyl group, or organic groups having from 1 to 5 carbon atoms and containing an allyl group, more preferably at least three of X ¹ to X ⁵ are vinyl groups or allyl groups, even more preferably four of X ¹ to X ⁵ are vinyl groups or allyl groups, and even more preferably four of X ¹ to X ⁵ are allyl groups.
In addition, in formula (2-a), when none of X ¹ to X ³ contains an organic group represented by formula (2-b), all of X ¹ to X ³ are organic groups containing a vinyl group and having 1 to 10 carbon atoms or organic groups containing an allyl group and having 1 to 10 carbon atoms, preferably all of X ¹ to X ³ are organic groups containing a vinyl group and having 1 to 5 carbon atoms or organic groups containing an allyl group and having 1 to 5 carbon atoms, more preferably all of X ¹ to X ³ are vinyl groups or allyl groups, and even more preferably all of X ¹ to X ³ are allyl groups.
In addition, in formula (2-a), when one of X ¹ to X ³ is an organic group represented by formula (2-b), at least three of X ¹ to X ⁵ are organic groups containing a vinyl group and having 1 to 10 carbon atoms or organic groups containing an allyl group and having 1 to 10 carbon atoms, preferably at least three of X ¹ to X ⁵ are organic groups containing a vinyl group and having 1 to 5 carbon atoms or organic groups containing an allyl group and having 1 to 5 carbon atoms, more preferably at least three of X ¹ to X ⁵ are vinyl groups or allyl groups, even more preferably four of X ¹ to X ⁵ are vinyl groups or allyl groups, and even more preferably four of X ¹ to X ⁵ are allyl groups.
In formula (2-b), Y is, for example, a carbonyl group or a chain-like divalent group containing a hydrocarbon group having 2 or more carbon atoms (preferably 2 or more and 18 or less). The chain-like divalent group containing a hydrocarbon group having 2 or more carbon atoms (preferably 2 or more and 18 or less) may have an ether group in the main chain, or may have a hydroxy group in the side chain. Examples of the chain-like divalent group containing a hydrocarbon group having 2 or more carbon atoms (preferably 2 or more and 18 or less) are divalent groups represented by any of the following formulae (3-a) to (3-c):

In formula (3-a), m represents an integer of 2 or more, preferably an integer of 2 to 18. In formula (3-c), n represents an integer of 0 or 1 or more, preferably 0 or 1.

Examples of glycoluril-based crosslinking compounds include 1,3,4,6-tetraallyl glycoluril (e.g., TA-G manufactured by Shikoku Chemical Industries, Ltd.), 1,3,4,6-tetraallyl-3a-methyl glycoluril, 1,3,4,6-tetraallyl-3a,6a-dimethyl glycoluril, and 1,3,4,6-tetraallyl-3a,6a-diphenyl glycoluril. Examples of bisisocyanurate-based crosslinking compounds include bis(diallyl isocyanurate) compounds (e.g., DD-1 manufactured by Shikoku Chemical Industries, Ltd.). Examples of isocyanurate-based crosslinking compounds include triallyl isocyanurate (e.g., TAIC manufactured by Mitsubishi Chemical Corporation).

When the resin composition of this embodiment contains a crosslinking aid, the content of the crosslinking aid in the resin composition of this embodiment is 6 parts by mass or more, preferably 7 parts by mass or more, more preferably 8 parts by mass or more, and even more preferably 9 parts by mass or more, per 100 parts by mass of the thermosetting cyclic olefin (co)polymer (m), from the viewpoint of further improving the performance balance of low dielectric constant, crosslinkability, and heat resistance in the high frequency range. The upper limit of the content of the crosslinking aid in the resin composition of this embodiment is not particularly limited, but is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 30 parts by mass or less, and may be, for example, 20 parts by mass or less, 15 parts by mass or less, or 13 parts by mass or less.

The crosslinking aid contained in the resin composition of this embodiment may further contain a crosslinking aid other than the crosslinkable compound (a). Examples of crosslinking aids include, but are not limited to, oximes such as p-quinone dioxime and p,p'-dibenzoylquinone dioxime; (meth)acrylates such as ethylene di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, cyclohexyl (meth)acrylate, acrylic acid/zinc oxide mixtures, and allyl (meth)acrylate; vinyl monomers such as divinylbenzene, vinyltoluene, and vinylpyridine; allyl compounds such as hexamethylenediallylnadimide, diaryl itaconate, diallyl phthalate, diallyl isophthalate, and diallyl monoglycidyl isocyanurate; and maleimide compounds such as N,N'-m-phenylene bismaleimide and N,N'-(4,4'-methylenediphenylene)dimaleimide. These crosslinking aids may be used alone or in combination.

The content of crosslinkable compound (a) in the crosslinking aid contained in the resin composition of this embodiment is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, even more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, even more preferably 95 parts by mass or more, even more preferably 98 parts by mass or more, even more preferably 100 parts by mass or more, and preferably 100 parts by mass or less, per 100 parts by mass of the crosslinking aid contained in the resin composition of this embodiment.

[Other radical initiators]
The resin composition of the present embodiment may contain a radical initiator other than the radical initiator (A) (hereinafter referred to as other radical initiator).

Other radical initiators that can be used in combination include known thermal radical initiators and photoradical initiators. When using a thermal radical initiator among these radical initiators, from the viewpoint of storage stability, it is recommended that the 10-hour half-life temperature be, for example, 80°C or higher, preferably 120°C or higher. Examples of such 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, ethyl-3,3-bis(t-butylperoxy)butyrate, 3,3,6,6,9,9-hexamethyl-1,2, Examples include peroxyketals such as 4,5-tetraoxycyclononane; peroxyesters such as bis(t-butylperoxy)isophthalate, t-butylperoxybenzoate, and t-butylperoxyacetate; hydroperoxides such as t-butyl hydroperoxide, t-hexyl hydroperoxide, cumin hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, and p-menthane hydroperoxide; bibenzyl compounds such as hexaphenylethane, 1-t-butyl-3-[2-(4-t-butylphenyl)-1,1,2-trimethylpropyl]benzene, and 2,3-dimethyl-2,3-diphenylbutane; and 3,3,5,7,7-pentamethyl-1,2,4-trioxepane.

Among other radical initiators, examples of photoradical initiators include benzoin alkyl ether, benzil 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. Sensitizers can also be used with these photoradical initiators. Examples of sensitizers 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.

The other radical initiators preferably include thermal radical initiators, and even more preferably bibenzyl compounds. This further improves storage stability and can further improve dielectric properties, heat resistance, and mechanical properties.

When the resin composition of this embodiment contains another radical initiator, the content of the other radical initiator in the resin composition of this embodiment is, from the viewpoint of further improving the performance balance between the heat resistance and mechanical properties of the cured product, preferably 0.02 parts by mass or more, more preferably 0.05 parts by mass or more, even more preferably 0.1 parts by mass or more, even more preferably 0.5 parts by mass or more, even more preferably 1.0 parts by mass or more, even more preferably 1.5 parts by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 2.5 parts by mass or more, even more preferably 3.0 parts by mass or more, and even more preferably 3.5 parts by mass or more, per 100 parts by mass of the thermosetting cyclic olefin (co)polymer (m), and from the viewpoint of further improving the dielectric properties of the cured product, is preferably 20.0 parts by mass or less, more preferably 10.0 parts by mass or less, and even more preferably 5.0 parts by mass or less.

[Antioxidant (B)]
The resin composition of the present embodiment preferably further contains an antioxidant (B).

The antioxidant (B) preferably contains one or more antioxidants selected from the group consisting of phenolic antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and thioether-based antioxidants, and more preferably contains a phenolic antioxidant. This can further improve the storage stability of the resin composition during storage and after it has been formed into a film.

Phenol-based antioxidants include, for example, acrylate-based phenolic 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-(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-tetraoxaspiro[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, tetra Alkyl-substituted phenolic compounds such as kis(methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenylpropionate)methane [i.e., pentaerythrimethyl-tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenylpropionate)], pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, triethylene glycol bis(3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate), and tocophenol; 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, 2-octylthio-4,6-bis-(3,5-di-t-butyl-4-oxyanilino)-1,3,5-triazine, and other triazine group-containing phenolic compounds. Among these, at least one selected from the group consisting of acrylate-based phenolic compounds and alkyl-substituted phenolic compounds is preferred, with alkyl-substituted phenolic compounds being more preferred.

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 octyl phosphite, 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-butylphenyl-di-tridecyl) bis(diphenyl monoalkyl (C12 to C15) phosphite), 4,4'-isopropylidene-bis(diphenyl monoalkyl (C12 to 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 neopentane tetrayl bis(isodecyl phosphite), cyclic neopentane tetrayl bis(nonylphenyl phosphite), cyclic neopentane tetrayl bis(2,4-di-t-butylphenyl phosphite), cyclic neopentane tetrayl bis(2,4-dimethylphenyl phosphite), cyclic neopentane tetrayl bis(2,6-di-t-butylphenyl phosphite), and the like. Among these, monophosphite compounds are preferred, and at least one selected from the group consisting of tris(nonylphenyl)phosphite, tris(dinonylphenyl)phosphite, tris(2,4-di-t-butylphenyl)phosphite, etc. is more preferred.

Examples of sulfur-based antioxidants include at least one selected from the group consisting of dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, laurylstearyl 3,3-thiodipropionate, pentaerythritol-tetrakis-(β-lauryl-thio-propionate), and 3,9-bis(2-dodecylthioethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane.
Examples of the thioether antioxidant include at least one selected from the group consisting of 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.

When the resin composition of the present embodiment contains an antioxidant (B), the content of the antioxidant (B) in the resin composition of the present embodiment is, from the viewpoint of further improving storage stability, preferably 0.001% by mass or more, more preferably 0.005% by mass or more, even more preferably 0.01% by mass or more, and still more preferably 0.02% by mass or more, and is preferably 1.0% by mass or less, more preferably 0.50% by mass or less, even more preferably 0.30% by mass or less, even more preferably 0.20% by mass or less, and still more preferably 0.10% by mass or less, based on the entire resin composition excluding the solvent.
Furthermore, when the resin composition of the present embodiment contains the antioxidant (B), the content of the antioxidant (B) in the resin composition of the present embodiment is, from the viewpoint of further improving storage stability, preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and may be, for example, 1.0 part by mass or less, 0.5 part by mass or less, or 0.1 part by mass or less, relative to 100 parts by mass of the thermosetting cyclic olefin (co)polymer (m).

[Additives]
The resin composition of the present embodiment may further contain various additives depending on the intended purpose. The amount of the additives added is appropriately selected depending on the intended use within a range that does not impair the object of the present invention.
The additives may be one or more additives selected from the group consisting of heat stabilizers, weather stabilizers, radiation resistant 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 wettability improvers, fillers, hydrochloric acid absorbers, and metal deactivators.
For example, the heat stabilizers, light stabilizers, ultraviolet absorbers, radiation resistant 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 absorbers, metal deactivators, etc. described in paragraphs 0085 to 0120 of WO 2017/150218 can be used.

The resin composition of this embodiment can be prepared by mixing the thermosetting cyclic olefin (co)polymer (m) and the radical initiator (A), and, if necessary, other components. Mixing methods that can be used include melt blending using an extruder or the like, or solution blending, in which the components are dissolved or dispersed in an appropriate solvent, such as a saturated hydrocarbon such as heptane, hexane, decane, or cyclohexane; or an aromatic hydrocarbon such as toluene, benzene, or xylene.

The dielectric tangent at 10 GHz of the cured product obtained by heating the resin composition of this embodiment at 200°C is preferably less than 0.0020, more preferably less than 0.0018, even more preferably less than 0.0016, even more preferably less than 0.0014, even more preferably less than 0.0013, and even more preferably less than 0.0012, from the viewpoint of further improving the performance balance of low dielectric properties, crosslinkability, and heat resistance in the high frequency range, and may be, for example, 0.0001 or more, 0.0003 or more, or 0.0005 or more.

The dielectric loss tangent at 10 GHz of the cured product obtained by heating the resin composition of the present embodiment at 200° C. can be obtained by the following <Method 1>.
<Method 1>
First, the resin composition of the present embodiment is applied to a release-treated PET film at a speed of 10 mm/sec, and then dried for 4 minutes at 150°C in a nitrogen gas flow in a blower dryer to obtain a laminated film of the PET film and the resin composition of the present embodiment.
Two sheets of the obtained laminated film are stacked so that the resin compositions are in contact with each other, and the press pressure is increased to 3.5 MPa under a vacuum controlled to 20 kPa or less using a vacuum press. The temperature is increased from room temperature (25°C) at a constant rate, and the film is maintained at 180°C for 60 minutes. Thereafter, the film is peeled off from the PET film to obtain a pre-cured laminated film.
The obtained pre-cured laminated film is sandwiched between polyimide films, and a pressure of 3.5 MPa is applied using a vacuum press under a vacuum controlled to 20 kPa or less. The temperature is raised from room temperature (25°C) at a constant rate, and the film is held at 200°C for 120 minutes. Thereafter, the film is peeled off from the polyimide films to obtain a cured laminated film.
The dielectric loss tangent Df at 10 GHz of the resulting cured laminated film is measured by a cylindrical cavity resonator method.

In the resin composition of this embodiment, ΔTg represented by the following formula (10) is preferably 30° C. or higher, more preferably 35° C. or higher, even more preferably 38° C. or higher, even more preferably 40° C. or higher, and still more preferably 43° C. or higher, from the viewpoint of further improving the performance balance of low dielectric property, crosslinkability, and heat resistance in the high frequency region. The upper limit of ΔTg is not particularly limited, but is, for example, 80° C. or lower, or may be 70° C. or lower, or may be 60° C. or lower.
ΔTg=Tg ₁ - Tg ₀ (10)
In formula (10), Tg ₀ is the glass transition temperature of the thermosetting cyclic olefin (co)polymer (m) of this embodiment, and Tg ₁ is the glass transition temperature of the cured product obtained by heating the resin composition of this embodiment at 200°C.

Tg ₀ can be determined by the following <Method 2>.
<Method 2>
First, the thermosetting cyclic olefin (co)polymer (m) of this embodiment is subjected to DSC measurement under an N ₂ (nitrogen) atmosphere under the following temperature conditions to obtain an endothermic curve. Then, the temperature of the endothermic peak of the obtained endothermic curve is designated as Tg ₀ .
<Temperature conditions>
The temperature is raised from 25°C to 200°C at a rate of 10°C/min, and then held for 5 minutes. The temperature is then lowered to -20°C at a rate of 10°C/min, and then held for 5 minutes. The temperature is then raised to 200°C at a rate of 10°C/min.

Tg ₁ can be determined by the following <Method 3>.
<Method 3>
The solid viscoelastic temperature dispersion of the cured laminate film obtained by the above <Method 1> is measured under the following conditions, and the peak temperature of the loss tangent (tan δ) is defined as Tg1. The glass transition temperature of the cured product obtained by heating the resin composition of the present embodiment at 200°C is defined as _Tg1 .
Deformation mode: Tensile Temperature range: 25℃ to 300℃
Temperature increase rate: 3°C/min Frequency: 1Hz
Set distortion: 0.1%
Environment: Nitrogen atmosphere

The glass transition temperature _Tg1 of the cured product obtained by heating the resin composition of this embodiment at 200°C is preferably 130°C or higher, more preferably 135°C or higher, and even more preferably 138°C or higher, from the viewpoint of further improving the performance balance of low dielectric constant, crosslinkability, and heat resistance in the high frequency range. The upper limit of _Tg1 is not particularly limited, and may be, for example, 200°C or lower, 180°C or lower, 170°C or lower, or 160°C or lower.

2. Varnish The varnish of this embodiment will now be described.

The varnish of this embodiment contains the resin composition of this embodiment and 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 (co)polymer (m) and the crosslinking aid.Preferred solvents include 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; 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 coating properties 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 500 parts by mass or less, more preferably 450 parts by mass or less, and even more preferably 400 parts by mass or less, when the total amount of the resin composition is 100 parts by mass.
The total content of the thermosetting cyclic olefin (co)polymer (m) and the crosslinking aid in the varnish is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and is preferably less than 100% by mass, and more preferably 50% by mass or less.

In this embodiment, the method for preparing the varnish may be carried out by any method, for example, including a step of mixing a resin composition and a solvent. The order in which the components are mixed is not limited, and the components may be mixed in any manner, such as all at once or in portions. The apparatus for preparing the varnish is also not limited, 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 (co)polymer (m) is obtained as it is as a solvent.

3. Cured Product The cured product of this embodiment will now be described.

The cured product of this embodiment can be obtained by crosslinking the thermosetting cyclic olefin (co)polymer (m) in the resin composition of this embodiment. The crosslinking can be carried out, for example, by a crosslinking step in which the resin composition is crosslinked under a vacuum of 20 kPa or less, at a temperature of 150°C or higher, and at a pressure of 0.2 MPa or higher.
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 resulting cured product, and is preferably 280°C or lower, more preferably 260°C or lower, even more preferably 250°C or lower, and even more preferably 240°C or lower, from the viewpoint of suppressing thermal decomposition of the thermosetting cyclic olefin (co)polymer (m) and the cured product.
The pressing pressure in the crosslinking step is 0.2 MPa or more, preferably 1 MPa or more, more preferably 2 MPa or more, and even more preferably 3 MPa or more, from the viewpoint of ensuring the uniformity of the resulting cured product.
In order to maintain the dielectric properties 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.

The crosslinking step can be carried out with the resin composition of the present embodiment in a molten state, or with the resin composition in a solution state where it is dissolved or dispersed in a solvent. Alternatively, the crosslinking step can be carried out by volatilizing the solvent from a solution state where the resin composition is dissolved in a solvent, forming the resin composition into any shape such as a film or coating, and then further promoting 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. Alternatively, 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.

4. Prepreg The prepreg of this embodiment will now be described.

The prepreg of this embodiment is formed by impregnating a fiber substrate with the resin composition of this embodiment or the varnish of this embodiment.

The prepreg of this embodiment is preferably formed by combining the resin composition of 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 it 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 thereof include a batch method of drying in air or nitrogen using a blower dryer, or a continuous method of drying 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.

The fibers constituting the sheet-like fiber substrate can be inorganic or organic fibers, and are not particularly limited. Examples include 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; and 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. 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, of the prepreg or laminate. If it is in this range, the dielectric properties and mechanical strength of the resulting laminate are well balanced, which is preferable.

The thickness of the prepreg is selected appropriately depending on the intended 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. Within this range, the shapeability during lamination and the mechanical strength and toughness of the laminate obtained upon curing are fully exhibited, making it ideal.

5. Film The film of this embodiment will now be described.

The film of this embodiment contains a cured product of the resin composition of this embodiment.

The resin composition of the present embodiment can be cured to form a cured product into a film for use in various applications. In the present embodiment, the term "film" is a general term for planar molded products, and is a concept that also includes sheets, membranes, tapes, and the like.
Various known methods can be used to cure the resin composition of this embodiment to form a cured product and then mold it into a film. For example, a method can be used in which the varnish described above is applied to a support substrate such as a thermoplastic resin film, dried, and then heat-treated to crosslink the resin composition to obtain a cured product, thereby forming a film made of the resin composition of this embodiment. Examples of thermoplastic resin films that can be used include PET films and polyimide resin films. The method for applying the varnish to the support substrate is not particularly limited, and examples include application using a spin coater, application using a spray coater, and application using a bar coater.
Another example is a method in which the resin composition of this embodiment is melt-molded to obtain a film, and then the resin composition is crosslinked by heat treatment or the like to form a cured product, thereby forming a film made of the resin composition of this embodiment.

6. Laminate The laminate of this embodiment will now be described.

The laminate of this embodiment includes the prepreg of this embodiment or the film of this embodiment.

The film or prepreg of this embodiment can be laminated on a substrate to form a laminate that can be used for various purposes, such as an organic insulating film that requires low dielectric properties or a curable adhesive sheet for a device having an adhesive layer.
Various known methods can be applied to form the laminate of this 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 film 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.

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

7. Metal Clad Laminate Hereinafter, the metal clad laminate of this embodiment will be described.

The metal clad laminate of this embodiment includes metal foil on at least one side of the laminate of this embodiment.

The laminate of the present embodiment may be formed into a metal clad laminate by laminating a metal foil on at least one surface of the laminate of the present embodiment and heat-curing the laminate by a lamination press or the like. Alternatively, the metal foil may be attached to both surfaces of the laminate.
Examples of metal foils 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 of 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 of this embodiment and, if necessary, heat-curing it by pressing or the like.

The metal clad laminate of this embodiment uses a cured product obtained by curing the resin composition of this embodiment, and therefore has an improved balance of low dielectric properties and heat resistance in the high frequency range, which is suitable for printed wiring boards.
Therefore, the metal clad laminate of this embodiment can be suitably used as an insulating layer material for printed wiring boards.

8. Printed Wiring Board The printed wiring board of this embodiment will now be described.

The printed wiring board of this embodiment is manufactured using the prepreg of this embodiment or the metal clad laminate of this embodiment.

The cured product obtained by curing the resin composition of this embodiment has an improved balance of low dielectric properties and heat resistance in the high frequency range, and can therefore be suitably used for printed wiring boards.
A commonly known method can be used to manufacture a printed wiring board, and is not particularly limited. For example, a film or laminate manufactured by the above-described method is heat-cured using a lamination press or the like to form an electrical insulating layer. Next, a conductor layer is laminated on the obtained electrical insulating layer using 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.

Metals that can be used for the conductor layer include, for example, copper, aluminum, nickel, gold, silver, and stainless steel. Methods for forming the conductor layer include, for example, forming the above metals into foil or the like and heat-fusing them onto the electrical insulating layer, forming the above metals into foil or the like and laminating it onto the electrical insulating layer using an adhesive, or forming a conductor layer made of the above metals on the electrical insulating layer by methods such as sputtering, vapor deposition, and plating. The printed wiring board may be either a single-sided board or a double-sided board.

9. Electronic Device The electronic device of this embodiment will now be described.

The electronic device of this embodiment includes the film of this embodiment or the printed wiring board of this embodiment.

The electronic device of this embodiment can be manufactured based on 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 phones, PDAs, and tablet terminals; digital devices such as personal computers, televisions, digital cameras, digital video cameras, POS terminals, wearable terminals, and digital media players; in-vehicle electronic devices such as electronic control system devices, in-vehicle communication devices, car navigation devices, millimeter-wave radars, and in-vehicle camera modules; semiconductor testing equipment, high-frequency measuring devices, and the like; and high-speed communication compatible modules.

The electronic device of this embodiment preferably includes a module compatible with high-speed communication.

The high-speed communication module of this embodiment is a high-speed communication module manufactured using the film of this embodiment or the printed wiring board of this embodiment.
The high-speed communication module of this embodiment is, for example, a communication module in which a semiconductor chip or the like is mounted on the printed wiring board of this embodiment, and is particularly suitable for applications that utilize high-frequency signals, such as wireless communication equipment and network infrastructure equipment, and require large amounts of information communication at high speeds.

The cured product obtained by curing the resin composition of this embodiment has a good balance of low dielectric properties and heat resistance in the high frequency region, and therefore can 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 devices, 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 types of 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, aerospace components, semiconductor processing 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 of the present embodiment has an improved balance of low dielectric properties and heat resistance in the high frequency range, and also has a good balance of performance such as insulating properties and mechanical properties, so it can be suitably used for printed wiring boards, and can be more suitably used for high frequency applications such as high frequency printed wiring boards.

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

The present embodiment will be described in detail below with reference to examples. Note that the present embodiment is in no way limited to the descriptions of these examples.

The raw materials used to prepare the resin composition are as follows:

[Thermosetting cyclic olefin (co)polymer (m)]
Thermosetting cyclic olefin copolymer (m-1) (synthesis method will be described later)

[Radical initiator (A)]
DEDPH (2,3-diethyl-2,3-diphenylhexane, manufactured by Fluorochem; in general formula (1), R ₁ to R ₁₀ are hydrogen atoms, and R ₁₁ to R ₁₄ are ethyl groups).

[Other radical initiators]
Percumyl D (dicumyl peroxide, product name: Percumyl D, manufactured by NOF Corporation)
VR-110 (2,2'-azobis(2,4,4-trimethylpentane), product name: VR-110, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
DMDPB (2,3-dimethyl-2,3-diphenylbutane, manufactured by Acros Organics; in general formula (1), R ₁ to R ₁₀ are hydrogen atoms, and R ₁₁ to R ₁₄ are methyl groups).

[Antioxidant (B)]
Irganox 1010 (pentaerythritol tetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, product name: Irganox 1010, manufactured by BASF)

The following raw materials were used to synthesize the thermosetting cyclic olefin copolymer (m-1).
Transition metal compound (1):
It was synthesized by the method described in JP-A-2004-331965.

Modified methylaluminoxane (MMAO, manufactured by Tosoh Finechem Co., Ltd.)
Toluene (Wako Pure Chemical Industries, Ltd.: Wako Special Grade)
5-vinyl-2-norbornene (hereinafter referred to as VNB) (manufactured by Tokyo Chemical Industry Co., Ltd.)
Tetracyclo[ ^{4.4.0.12,5.17,10} ]-3-dodecene (hereinafter referred to ^as TD) (manufactured by Mitsui Chemicals, Inc.)
Methanol (Fujifilm Wako Pure Chemical Industries, Ltd.: Wako Special Grade)

[Method for measuring the content of each structural unit constituting a cyclic olefin (co)polymer]
The contents of the repeating unit (A), the repeating unit (B) and the repeating unit (C) were measured using a nuclear magnetic resonance spectrometer "EXcalibur 270" manufactured by JEOL Ltd. under the following conditions.
Accumulation count: 16 to 64 times Measurement temperature: Room temperature (25°C)
From the ¹ H-NMR spectrum obtained in the above measurement, the intensity of the peak derived from hydrogen directly bonded to the double bond carbon and the peak derived from other hydrogen were calculated.

[Glass transition temperature Tg ₀ of thermosetting cyclic olefin (co)polymer (m)]
First, the thermosetting cyclic olefin (co)polymer (m) was subjected to DSC measurement under an N ₂ (nitrogen) atmosphere under the following temperature conditions to obtain an endothermic curve. The temperature of the endothermic peak of the obtained endothermic curve was then determined as the glass transition temperature Tg ₀ of the thermosetting cyclic olefin (co)polymer (m). The DSC measurement instrument used was a DSC-6220 manufactured by Shimadzu Science Corporation.
<Temperature conditions>
The temperature is raised from 25°C to 200°C at a rate of 10°C/min, and then held for 5 minutes. The temperature is then lowered to -20°C at a rate of 10°C/min, and then held for 5 minutes. The temperature is then raised to 200°C at a rate of 10°C/min.

[Synthesis Example 1]
A 1 L SUS autoclave, thoroughly purged with nitrogen, was charged with 450 ml of toluene, 30 ml of VNB, 16 ml of TD, 0.9 mmol of a hexane solution of MMAO (calculated as Al), and 360 ml of hydrogen, and then ethylene was introduced into the system until the total pressure reached 0.6 MPa. A toluene solution of 0.028 mmol of transition metal compound (1) was added, and polymerization was carried out at 35°C for 180 minutes. The polymerization was then terminated by injecting 1 ml of methanol under pressure. Ion-exchanged water was added to the resulting polymer solution, and the mixture was stirred for 1 hour. The organic layer was then filtered through filter paper. This organic layer was poured into acetone to precipitate a polymer, which was stirred and then filtered through filter paper. The resulting polymer was dried under reduced pressure at 80°C for 10 hours to obtain an ethylene/TD/VNB copolymer (hereinafter referred to as thermosetting cyclic olefin copolymer (m-1)), which is a thermosetting cyclic olefin (co)polymer (m).
The compositional ratio of the TD-derived structure in the polymer determined by NMR of the obtained thermosetting cyclic olefin copolymer (m-1) was 12 mol %, the compositional ratio of the VNB-derived structure in the polymer was 26 mol %, and the number average molecular weight (Mn) determined by GPC measurement was 21,000 and the glass transition temperature Tg was 99°C.

[Example 1]
(Preparation of Varnish)
To the thermosetting cyclic olefin copolymer (m-1) obtained in Synthesis Example 1, a radical initiator and an antioxidant weighed according to the formulation in Table 1 were added, and toluene was added as a solvent, followed by stirring until fully dissolved, to obtain the desired varnish-like cyclic olefin copolymer resin composition. The blending ratio of each raw material in Table 1 is expressed in parts by mass.

(Preparation of cured laminated film)
The obtained varnish-like cyclic olefin copolymer resin composition was applied to a release-treated PET film at a speed of 10 mm/sec, and then dried at 150°C for 4 minutes in a nitrogen gas flow in a blower dryer to obtain a laminate film of the PET film and the composition. Two laminate films were prepared.
Two of the obtained laminated films were stacked so that the surfaces coated with the resin composition were in contact with each other, and the press pressure was increased to 3.5 MPa under a vacuum controlled to 20 kPa or less using a vacuum press. The temperature was raised from room temperature (25°C) at a constant rate and maintained at 180°C for 60 minutes, after which the film was peeled off from the PET film to obtain a pre-cured laminated film.
The obtained pre-cured laminated film was sandwiched between polyimide films, and a pressure of 3.5 MPa was applied using a vacuum press under a vacuum controlled to 20 kPa or less. The temperature was raised from room temperature (25°C) at a constant rate and maintained at 200°C for 120 minutes, after which the film was peeled off from the polyimide films to obtain a cured laminated film.
The resulting cured laminated film was used to measure the dielectric loss tangent and evaluate the heat resistance according to the following procedures.

[Dielectric loss tangent evaluation]
The dielectric loss tangent Df at 10 GHz of the cured laminated films obtained in the Examples and Comparative Examples was measured by a cylindrical cavity resonator method. The results are shown in Table 1.

[Heat resistance evaluation]
The solid viscoelastic temperature dispersion of the cured laminate films obtained in the Examples and Comparative Examples was measured under the conditions below, and the peak temperature of the loss tangent (tan δ) was taken as the glass transition temperature _Tg1 of the cured product obtained by heating the resin composition of this Example at 200°C.
Apparatus: RSA-III (manufactured by TA Instruments)
Deformation mode: Tensile Temperature range: 25℃ to 300℃
Temperature increase rate: 3°C/min Frequency: 1Hz
Set distortion: 0.1%
Environment: Nitrogen atmosphere Then, ΔTg was calculated from the glass transition temperature Tg ₁ of the cured product obtained by heating the resin composition of this example obtained by the above method at 200°C and Tg ₀ of the thermosetting cyclic olefin copolymer (m-1) according to the following formula (10):
ΔTg=Tg ₁ - Tg ₀ (10)
The results obtained are shown in Table 1.
In this evaluation, it was determined that the larger the ΔTg, the more improved the heat resistance.

[Example 2 and Comparative Examples 1 to 3]
A varnish and a laminated film were prepared and evaluated under the same conditions as in Example 1, except that the blending composition and pressing temperature were changed as shown in Table 1. The pressing temperature of the laminated film before curing is shown in Table 1. The obtained results are shown in Table 1.

The resin compositions of the examples were able to produce cured products with an improved balance of low dielectric properties and heat resistance in the high frequency range at crosslinking temperatures of 200°C or less. This shows that the resin composition of this embodiment can produce cured products with an improved balance of low dielectric properties and heat resistance in the high frequency range at crosslinking temperatures of 200°C or less.

This application claims priority based on Japanese Patent Application No. 2024-035037, filed March 7, 2024, the disclosure of which is incorporated herein in its entirety.

Claims (22)

A resin composition comprising a thermosetting cyclic olefin (co)polymer (m) having a crosslinkable group (α) and a radical initiator (A),
The resin composition, wherein the radical initiator (A) contains a compound represented by the following general formula (1):
[In general formula (1), R ₁ to R ₁₀ are each independently a hydrogen atom, a halogen atom, an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms; R ₁₁ to R ₁₄ are each independently an alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms; and at least one of R ₁₁ to R ₁₄ is each independently an alkyl group having from 2 to 20 carbon atoms, a cycloalkyl group having from 3 to 20 carbon atoms, an aromatic hydrocarbon group having from 6 to 20 carbon atoms, or a halogenated alkyl group having from 1 to 20 carbon atoms] 2. The resin composition according to claim 1, wherein, in the general formula (1), R ₁ to R ₁₀ each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, or an aromatic hydrocarbon group having 6 to 20 carbon atoms. The resin composition according to claim 2, wherein in the general formula (1), R ₁ to R ₁₀ are hydrogen atoms. 3. The resin composition according to claim 1, wherein in the general formula (1), R ₁₁ to R ₁₄ each independently represent an alkyl group having 2 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or a halogenated alkyl group having 1 to 20 carbon atoms. The resin composition according to claim 4, wherein in the general formula (1), R ₁₁ to R ₁₄ each independently represent an alkyl group having 2 to 20 carbon atoms. The resin composition according to claim 5 , wherein in the general formula (1), R ₁₁ to R ₁₄ are ethyl groups. The resin composition according to claim 1 or 2, wherein the content of the radical initiator (A) in the resin composition is 0.02 parts by mass or more and 20.0 parts by mass or less per 100 parts by mass of the thermosetting cyclic olefin (co)polymer (m). The thermosetting cyclic olefin (co)polymer (m) is
(A) one or more olefin-derived repeating units represented by the following general formula (I),
(B) one or more repeating units derived from a cyclic non-conjugated diene represented by the following general formula (III),
The resin composition according to claim 1 or 2, further comprising: (C) one or more repeating units derived from cyclic olefins represented by the following general formula (V):
[In the above general formula (I), R ³⁰⁰ represents a hydrogen atom or a linear or branched hydrocarbon group having 1 to 29 carbon atoms.]
[In the above general formula (III), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, R ⁶¹ to R ⁷⁶ , R ^a1 and R ^b1 may be the same or different and represent 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 monocycle or polycycle.]
[In the above general formula (V), u is 0 or 1, v is 0 or a positive integer, w is 0 or 1, R ⁶¹ to R ⁷⁸ , R ^a1 and R ^b1 may be the same or different and represent 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, and R ⁷⁵ to R ⁷⁸ may be bonded to each other to form a monocycle or polycycle.] When the total number of moles of repeating units in the thermosetting cyclic olefin (co)polymer (m) is taken as 100 mol%,
the content of the olefin-derived repeating unit (A) is 10 mol% or more and 90 mol% or less;
The resin composition according to claim 8, wherein the content of the repeating unit (B) derived from the cyclic non-conjugated diene is 1 mol % or more and 40 mol % or less, and the content of the repeating unit (C) derived from the cyclic olefin is 1 mol % or more and 50 mol % or less. The resin composition according to claim 8, wherein the cyclic non-conjugated diene constituting the cyclic non-conjugated diene-derived repeating unit (B) includes 5-vinyl-2-norbornene. The cyclic olefin constituting the cyclic olefin-derived repeating unit (C) comprises at least one selected from the group consisting of tetracyclo[4.4.0.1 ^2,5 . 1 ^7,10 ]-3-dodecene and bicyclo[2.2.1]-2-heptene. The resin composition according to claim 8. The resin composition according to claim 1 or 2, further comprising an antioxidant (B). The resin composition according to claim 1 or 2, wherein the cured product obtained by heating the resin composition at 200°C has a dielectric dissipation factor at 10 GHz of less than 0.0020. The resin composition according to claim 1 or 2, wherein ΔTg represented by the following formula (10) is 30° C. or higher.
ΔTg=Tg ₁ - Tg ₀ (10)
(In formula (10), Tg ₀ is the glass transition temperature of the thermosetting cyclic olefin (co)polymer (m), and Tg ₁ is the glass transition temperature of the cured product obtained by heating the resin composition at 200°C.) A varnish comprising the resin composition according to claim 1 or 2 and a solvent. A prepreg obtained by impregnating a fiber substrate with the resin composition described in claim 1 or 2 or the varnish described in claim 15. A film comprising a cured product of the resin composition described in claim 1 or 2. A laminate comprising the prepreg of claim 16 or the film of claim 17. A metal clad laminate comprising a metal foil on at least one surface of the laminate described in claim 18. A printed wiring board manufactured using the prepreg described in claim 16 or the metal clad laminate described in claim 19. An electronic device comprising the film of claim 17 or the printed wiring board of claim 20. The electronic device of claim 21, wherein the electronic device includes a high-speed communication-enabled module.