Copolymer, composition containing copolymer, and cured product thereof

Abstract

An α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, the copolymer in an uncured state having: a dielectric constant of less than 2.5 and a dielectric loss tangent of less than 0.0007 at a measurement frequency of 40 GHz; and a storage modulus of less than 1,000 MPa as measured at 25°C.

Description

Copolymer, composition containing copolymer, and cured product thereof

[0001] The present invention relates to a copolymer, a composition containing the copolymer, and a cured product thereof.

[0002] As communication frequencies move into the gigahertz range and higher, there is a growing need for multilayer substrates made of CCL or FCCL, which contain insulating materials with low dielectric properties. Fluorine-based resins such as perfluoroethylene have the characteristics of an excellent low dielectric constant, low dielectric loss, and excellent heat resistance, but they have difficulties in moldability and film formability, and also have issues with adhesion to copper foil for wiring, making them difficult to apply to multilayer substrates. Meanwhile, substrates and insulating materials made from post-curing resins such as epoxy resin, unsaturated polyester resin, polyimide resin, and phenolic resin have been widely used due to their heat resistance and ease of handling, but their relatively high dielectric constant and dielectric loss leave room for improvement as insulating materials for high frequencies (see Patent Document 1).

[0003] Therefore, hydrocarbon-based resins with inherently low dielectric properties have attracted attention. Cyclic olefin (co)polymers with particularly high glass transition temperatures (Tg) have been proposed as thermoplastic insulating materials. However, because their glass transition temperatures are close to the solder reflow temperature, crosslinkable (curable) resins are preferable in terms of process compatibility and process window. Converting hydrocarbon-based resins, which are essentially thermoplastic resins, into curable resins requires the introduction of crosslinkable functional groups. However, functional groups that react to radicals or heat generally contain oxygen or nitrogen atoms, making them polar, thereby degrading their low dielectric properties. Patent Document 2 discloses a cured product obtained from a specific coordination polymerization catalyst and consisting of an ethylene-olefin (aromatic vinyl compound)-aromatic polyene copolymer with a specific composition and blend, and a non-polar vinyl compound. This technology selectively copolymerizes only one of the two vinyl groups of the aromatic polyene (divinylbenzene), preserving the remaining vinyl group, making it easy to obtain a crosslinkable hydrocarbon-based copolymer macromonomer consisting only of carbon and hydrogen atoms and containing an aromatic vinyl group functional group. Cured products obtained from compositions of similar olefin-aromatic vinyl compound-aromatic polyene copolymers and auxiliary materials, etc., are characterized by low dielectric constants and low dielectric loss tangents, and a wide range of physical properties, from soft to hard, can be imparted by selecting the composition and appropriate auxiliary materials (Patent Documents 3 and 4). The ethylene-styrene-divinylbenzene copolymer specifically described is a curable soft copolymer with excellent low dielectric properties, and cured products of compositions containing this also have excellent low dielectric performance, but recently there has been a demand for even higher levels of low dielectric properties.

[0004] Japanese Patent Application Laid-Open No. 6-192392 Japanese Patent Application Laid-Open No. 2009-161743 International Publication No. 2021 / 112087 International Publication No. 2022 / 014599

[0005] In light of the above-mentioned background art, there is a demand for materials that have higher levels of low dielectric properties, flexibility, and are curable.

[0006] In view of the above-mentioned problems, the present invention can provide the following aspects.

[0007] Aspect 1: An α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, wherein the copolymer in an uncured state has a dielectric constant of less than 2.5 and a dielectric dissipation factor of less than 0.0007 at a measurement frequency of 40 GHz, and a storage modulus measured at 25°C of less than 1000 MPa.

[0008] Aspect 2: The copolymer according to aspect 1, wherein the total content of metals derived from the catalyst and co-catalyst contained in the copolymer is 1500 ppm or less.

[0009] Aspect 3: The copolymer according to aspect 1 or 2, wherein when cured alone, the cured product has a dielectric constant of less than 2.5 at a measurement frequency of 40 GHz, a dielectric dissipation factor of less than 0.0006, and a storage modulus measured at 25°C of less than 1000 MPa.

[0010] Aspect 4 The copolymer according to any one of Aspects 1 to 3, which, when cured alone, has a storage modulus of 1 MPa or more as measured at 280°C of the cured product.

[0011] Aspect 5: The copolymer according to any one of Aspects 1 to 4, which satisfies all of the following (1) to (6): (1) The number average molecular weight of the copolymer is 500 or more and 30,000 or less. (2) The α-olefin monomer units are α-olefin monomer units having 2 to 20 carbon atoms. (3) The aromatic vinyl compound monomer units are monomer units derived from an aromatic vinyl compound having 8 to 20 carbon atoms and one vinyl group or vinylene group in the molecule. (4) The cyclic olefin monomer units are cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 10% by mass or more and less than 50% by mass. (5) The aromatic polyene monomer is one or more selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and / or vinylene groups in the molecule, the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units contained in the copolymer is 2 or more per number average molecular weight, and the number average molecular weight per vinyl group and / or vinylene group derived from the aromatic polyene monomer units is 250 to 10,000. (6) The total of the α-olefin monomer units, cyclic olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass.

[0012] Aspect 6: The copolymer according to any one of Aspects 1 to 5, wherein the cyclic olefin monomer units comprise monomer units derived from one or more selected from the group consisting of norbornene, methylphenylnorbornene, substituted norbornenes other than methylphenylnorbornene, and dimethanooctahydronaphthalene.

[0013] Aspect 7 The copolymer according to any one of Aspects 1 to 6, wherein the uncured copolymer has a glass transition temperature determined by DSC in the range of −30° C. or higher and lower than 35° C.

[0014] Aspect 8: A method for producing the copolymer according to any one of Aspects 1 to 7, wherein each of the monomers of an α-olefin, a cyclic olefin, an aromatic vinyl compound, and an aromatic polyene is copolymerized by coordination polymerization using a coordination polymerization catalyst.

[0015] Aspect 9: The method for producing a copolymer according to Aspect 8, wherein the coordination polymerization catalyst is a polymerization catalyst comprising a transition metal compound represented by the following general formula (1) and a co-catalyst: In the formula, A and B are each independently a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzoindenyl group, an unsubstituted or substituted cyclopentadienyl group, or an unsubstituted or substituted indenyl group. Y is bonded to A and B and is a methylene group, silylene group, ethylene group, germylene group, or boron residue having hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as a substituent. The substituents may be different or the same. Y may also have a cyclic structure. X is hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylaryl group having 8 to 12 carbon atoms, a silyl group having a hydrocarbon substituent having 1 to 4 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having an alkyl substituent having 1 to 6 carbon atoms. M is zirconium, hafnium, or titanium.

[0016] Aspect 10: The method for producing the copolymer according to Aspect 9, wherein A and B in general formula (1) are each independently a group selected from an unsubstituted or substituted cyclopentadienyl group, or an unsubstituted or substituted indenyl group.

[0017] Aspect 11: The process according to aspect 9 or 10, wherein a cocatalyst containing a boron compound is used.

[0018] Aspect 12: The process of aspect 11, wherein the co-catalyst further comprises an aluminum compound.

[0019] Aspect 13: A cured product comprising the copolymer according to any one of aspects 1 to 7.

[0020] Aspect 14. A cured product of a composition comprising the copolymer according to any one of Aspects 1 to 7 and one or more additive components selected from the group consisting of a resin component, a curing agent, a monomer, a solvent, and a filler, wherein the cured product exhibits a dielectric constant of 3.5 or less and a dielectric loss tangent of 0.0015 or less at a measurement frequency of 40 GHz.

[0021] Aspect 15: A cured body for high frequency insulation substantially composed of a hydrocarbon-based material, wherein the value of Df(77 GHz / 10 GHz), which is the value of the dielectric loss tangent measured at 23°C and 77 GHz by the open resonator method (Fabry-Perot resonator method) relative to the dielectric loss tangent measured at 23°C and 10 GHz by the cavity resonator perturbation method (split cylinder resonator method), is 1.3 or less.

[0022] Aspect 16. The cured product according to Aspect 15, wherein the hydrocarbon-based material is a cured product comprising an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, the copolymer in an uncured state having a dielectric constant of less than 2.5 at a measurement frequency of 40 GHz, a dielectric dissipation factor of less than 0.0007, and a storage modulus measured at 25°C of less than 1000 MPa.

[0023] Aspect 17: A resin composition comprising the copolymer according to any one of Aspects 1 to 7 and an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following (a) to (f): (a) the number average molecular weight of the copolymer is 500 or more and 100,000 or less; (b) the α-olefin monomer units are α-olefin monomer units having 2 to 20 carbon atoms; (c) the aromatic vinyl compound monomer units are monomer units derived from an aromatic vinyl compound having 8 to 20 carbon atoms and one vinyl group or vinylene group in the molecule; (d) the cyclic olefin monomer units are cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 50% by mass or more and 99% by mass or less. (e) the aromatic polyene monomer units are monomer units derived from one or more polyenes selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units per number average molecular weight is 2 to 30. (f) The total of the α-olefin monomer units, cyclic olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass.

[0024] Aspect 18: A resin composition comprising the copolymer according to any one of Aspects 1 to 7 and an olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following (A) to (E): (A) the number average molecular weight of the copolymer is 500 or more and 100,000 or less; (B) the olefin monomer unit is a single or multiple units selected from α-olefin monomer units having 2 to 20 carbon atoms, and the olefin monomer unit does not include a cyclic olefin monomer unit; (C) the aromatic vinyl compound monomer unit is a monomer unit derived from an aromatic vinyl compound having 8 to 20 carbon atoms and one vinyl group or vinylene group in the molecule, and the content of the aromatic vinyl compound monomer unit is 0 to 90 mass%. (D) The aromatic polyene monomer units are monomer units derived from one or more polyenes selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and / or vinylene groups in the molecule, and the content of the vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units is 2 to 30 per number average molecular weight, and the content of the vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units is 2 to less than 30 per number average molecular weight. (E) The total of the olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass.

[0025] Aspect 19: A cured product of the resin composition according to aspect 17 or 18.

[0026] Aspect 20. The cured product according to aspect 13, 14, 15, 16, or 19, which is an electrical insulating material.

[0027] Aspect 21 A CCL substrate, an FCCL substrate, a resin coated copper (RCC), an interlayer insulating material, a coverlay, a high frequency transmission circuit, or an antenna, comprising the cured product according to aspect 20.

[0028] The copolymer according to the present invention has excellent low dielectric properties in an uncured state, excellent flexibility at room temperature, and curability. Furthermore, the copolymer or a cured product containing the copolymer has excellent low dielectric properties and can exhibit a wide range of physical properties from soft to hard depending on the blending.

[0029] This will be explained in more detail below. Numerical ranges in this specification include the upper and lower limits unless otherwise specified. In this specification, the term "sheet" also encompasses the concept of "film." Furthermore, the term "film" used in this specification is intended to have the same meaning as "sheet." Furthermore, the term "film" used in this specification is intended to encompass the concept of "sheet." In this specification, the term "uncured state" is defined as a state in which the gel fraction (gel content) of the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer is less than 50% by mass, preferably 20% by mass or less, more specifically 10% by mass or less, and most specifically 5% by mass or less. The gel fraction is a value obtained by measurement in accordance with JIS K6796:1998 or ASTM D2765-84, which corresponds to ISO 10147:1994, which corresponds to JIS. Furthermore, in this specification, the glass transition temperature (Tg) is determined by dynamic mechanical analysis (DMA) and differential scanning calorimeter (DSC). In the case of values ​​obtained by the DSC method, it is clearly stated that the values ​​are obtained by the DSC method, and other glass transition temperatures are obtained by the dynamic viscoelasticity measurement method.

[0030] In one embodiment of the present invention, an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer can be provided. In an uncured state, the copolymer may have a dielectric constant of less than 2.5, preferably 2.0 or greater but less than 2.5, and a dielectric dissipation factor of less than 0.0007, preferably 0.0002 or greater but less than 0.0007, at a measurement frequency of 40 GHz. It may also have a storage modulus measured at 25°C of less than 1000 MPa, preferably less than 800 MPa. When the copolymer is cured alone, the resulting cured product may have a dielectric constant of less than 2.5, preferably 2.0 or greater but less than 2.5, and a dielectric dissipation factor of less than 0.0006, preferably 0.0002 or greater but less than 0.0006, at a measurement frequency of 40 GHz. It may also have a storage modulus measured at 25°C of less than 1000 MPa, preferably less than 800 MPa. Furthermore, the storage modulus measured at 280°C of the cured product may preferably be 1 MPa or greater, more preferably 5 MPa or greater.

[0031] The dielectric properties of the cured product obtained from the copolymer (composition) of the present invention, particularly the dielectric loss tangent, are characterized by minimal change with measurement frequency. The characteristic of low signal frequency dependence of the dielectric loss tangent is important for maintaining signal quality and suppressing noise generation. For example, a square wave is synthesized from a wide range of frequency components with different frequencies. A low frequency dependence of the dielectric loss tangent (dielectric loss) is preferable because it suppresses deformation of the square wave during high-frequency signal transmission, facilitates accurate signal transmission, and suppresses noise. Specifically, the ratio of the dielectric loss tangent at 77 GHz measured at 23°C using the open resonator method (Fabry-Perot resonator method) to the dielectric loss tangent at 10 GHz measured at 23°C using the cavity resonator perturbation method (split cylinder resonator method), Df(77 GHz / 10 GHz), is preferably 0.8 to 1.3.

[0032] Another aspect of the present invention is a cured product for high-frequency insulation composed essentially of a hydrocarbon-based material, which has a ratio of the dielectric loss tangent at 77 GHz to the dielectric loss tangent at 10 GHz, Df (77 GHz / 10 GHz), measured by the above-mentioned method, of 1.3 or less. Here, "substantially hydrocarbon-based material" refers to the fact that 95% or more, preferably 98% or more, and most preferably 100% of the constituent atoms of the resin component of the cured product for high-frequency insulation, excluding fillers, flame retardants, and additives, are carbon and hydrogen atoms. Use of such a cured product for high-frequency insulation is preferable because it suppresses deformation of square waves during high-frequency signal transmission, ensuring accurate signal transmission and suppressing noise generation. The copolymer of the present invention is composed entirely of raw monomers consisting solely of carbon and hydrogen atoms, and the resin component of the copolymer is essentially 100% carbon and hydrogen atoms. While there is no particular limitation on the lower limit of Df (77 GHz / 10 GHz) of the cured product, it is preferably 0.8 or more.

[0033] In another embodiment, it is also possible to provide an embodiment in which the dielectric constant or dielectric loss tangent in the uncured state does not satisfy the above conditions, but the dielectric constant, dielectric loss tangent, and storage modulus of the cured product satisfy the above conditions.

[0034] <α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer> Furthermore, the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer of the present invention is a copolymer having monomer units of an α-olefin, a cyclic olefin, an aromatic vinyl compound, and an aromatic polyene, and its production method is optional. Preferably, the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer may be a copolymer satisfying all of the following (1) to (6): (1) The number average molecular weight of the copolymer is 500 or more and 30,000 or less. (2) The α-olefin monomer units are α-olefin monomer units having 2 to 20 carbon atoms. (3) The aromatic vinyl compound monomer units are monomer units derived from an aromatic vinyl compound having 8 to 20 carbon atoms and one vinyl group or vinylene group in the molecule. (4) The cyclic olefin monomer units are cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 10% by mass or more and less than 50% by mass, preferably 20% by mass or more and less than 40% by mass. (5) The aromatic polyene units are one or more selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and / or vinylene groups in the molecule, and preferably the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units contained in the copolymer is 2 or more per number average molecular weight, and the number average molecular weight per vinyl group and / or vinylene group derived from the aromatic polyene monomer unit is 300 to 10,000, more preferably 250 to 10,000. (6) The total of the α-olefin units, cyclic olefin units, aromatic vinyl compound units, and aromatic polyene units is 100% by mass.

[0035] The present α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer can be obtained by copolymerizing the respective monomers of α-olefin, cyclic olefin, aromatic vinyl compound, and aromatic polyene.

[0036] The α-olefin monomer (which refers to a monomer that is the basis of the α-olefin monomer units in the copolymer, but in this specification, the terms "monomer" and "monomer unit (or unit)" may be used interchangeably depending on the context; the same applies to similar terms hereinafter) may be an α-olefin monomer having from 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene. In view of compatibility with other materials, ethylene may be most preferred. In the present copolymer, the content of the α-olefin monomer units is optional, but may be preferably from 10 to 50% by mass, more preferably from 15 to 40% by mass, and even more preferably from 15 to 30% by mass. If the content of the α-olefin monomer units is too low, the flexibility may be impaired, and if it is too high, the dielectric loss tangent may be higher than the range specified in the present application.

[0037] As used herein, the term "cyclic olefin monomer" refers to a cyclic olefin having 7 to 30 carbon atoms. Cyclic olefins having 7 to 30 carbon atoms include cyclic olefins having one or more alicyclic structures in the molecule and a polymerizable vinyl group, vinylene group, or vinylidene group. Preferred cyclic olefins are cyclic olefins having a hydrocarbon ring structure without heteroatoms, and cyclic olefins having an unsaturated hydrocarbon ring are more preferred. Such cyclic olefins are characterized by low dielectric properties and high glass transition temperatures, while also possessing the notable advantage of being easily prepared using inexpensive raw materials and simple processes compared to conventional engineering plastics. Examples of such cyclic olefins include norbornenes and acenaphthylene. Norbornenes are monomers selected from norbornene and substituted norbornenes. Norbornene can be synthesized, for example, by the Diels-Alder reaction of ethylene and cyclopentadiene. The substituted norbornene is a substituted norbornene having a polymerizable vinyl group, vinylene group, or vinylidene group in the molecule, and examples thereof include dimethanooctahydronaphthalene (DMON) and trimethanododecahydroanthracene (TMDA). These are also Diels-Alder reaction products of norbornenes and cyclopentadiene. These substituted norbornenes are specifically described, for example, in International Publication No. 2006 / 118261. In the present invention, more preferred cyclic olefins are those having a larger number of ring structures and a higher molecular weight, such as dimethanooctahydronaphthalene (DMON) and trimethanododecahydroanthracene (TMDA). Copolymerization of such cyclic olefins allows for the production of copolymers with a higher glass transition temperature (Tg) at a lower mole percent content of the monomer unit. These high molecular weight cyclic olefins may be used alone or in mixtures with norbornene or the like for copolymerization. In particular, when the above-mentioned DMON or TMDA is produced by the Diels-Alder reaction, it may be obtained as a mixture with norbornene, and by using the mixture as it is for polymerization, it is possible to reduce the production cost.Furthermore, in the present invention, a more preferred cyclic olefin is a norbornene having an aromatic substituent, and examples thereof include phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), which is a Diels-Alder reaction product of cyclopentadiene and styrene, indanylnorbornene (1,4-methano-1,9a,4,4a-tetrahydrofluorene), which is a Diels-Alder reaction product of cyclopentadiene and indene, and methylphenylnorbornene (MPNB, 5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene), which is a Diels-Alder reaction product of cyclopentadiene and α-methylstyrene. When copolymerized, norbornenes having such aromatic substituents can impart a higher glass transition temperature (Tg) to the copolymer, and because they exhibit aromaticity, they can exhibit high compatibility with other aromatic raw materials (crosslinkable soft resins and flame retardants). Furthermore, the use of methylphenylnorbornene (5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene) is preferred because it can improve the thermal oxidation resistance of the resulting copolymer, as described in JP-A-2005-239975. Norbornenes having these aromatic substituents are specifically described, for example, in JP-A-11-504669 and JP-A-2005-239975. The optimum content of the cyclic olefin units contained in the copolymer varies depending on the type of cyclic olefin, but is, for example, 10% by mass or more and less than 50% by mass, 10% by mass or more and less than 40% by mass, 10% by mass or more and less than 30% by mass, 15% by mass or more and less than 50% by mass, 15% by mass or more and less than 40% by mass, 15% by mass or more and less than 30% by mass, 20% by mass or more and less than 50% by mass, 20% by mass or more and less than 40% by mass, or 20% by mass or more and less than 30% by mass. By having the content within these ranges, the copolymer can easily achieve both flexibility and low dielectric properties. The glass transition temperature of the copolymer is arbitrary, but is preferably determined by DSC method (2. ndThe glass transition temperature determined by the method (Run midpoint glass transition temperature) is preferably −80° C. or higher and lower than 50° C., more preferably −30° C. or higher and lower than 35° C. Those skilled in the art can appropriately adjust the type and content of the cyclic olefin to be used in order to achieve a preferred glass transition temperature.

[0038] In a preferred embodiment, the cyclic olefin monomer units contained in the copolymer may include one or more selected from the group consisting of norbornene, methylphenylnorbornene, substituted norbornenes other than methylphenylnorbornene, and dimethanooctahydronaphthalene, and more preferably, may include one or more selected from the group consisting of norbornene, methylphenylnorbornene, and dimethanooctahydronaphthalene.

[0039] The aromatic vinyl compound monomer may be an aromatic vinyl compound having from 8 to 20 carbon atoms, such as styrene, paramethylstyrene, ethylvinylbenzene, paraisobutylstyrene, various vinylnaphthalenes, and various vinylanthracenes. The monomer units derived from the aromatic vinyl compound may be contained in the copolymer as a result of copolymerization of aromatic vinyl compound components contained as impurities in the aromatic polyene used in polymerization. The content of aromatic vinyl compound monomer units in the copolymer is optional, but generally, the lower the content, the better the low dielectric properties. Furthermore, compatibility with cyclic olefin copolymers is improved. Conversely, a higher content of aromatic vinyl compound monomer units improves compatibility with other highly aromatic resin components and flame retardants. Those skilled in the art can adjust the content as appropriate depending on the purpose. Specifically, the content may be preferably from 10% to 60% by mass, more preferably from 20% to 50% by mass. The aromatic vinyl compound monomer has one vinyl group within the monomer.

[0040] The aromatic polyene monomer may be a polyene having 5 to 20 carbon atoms and containing multiple vinyl groups and / or vinylene groups in its molecule, preferably a polyene having 8 to 20 carbon atoms. The aromatic polyene monomer is preferably a polyene having 8 to 20 carbon atoms and containing multiple vinyl groups in its molecule, more preferably a compound having an aromatic vinyl structure, such as various ortho-, meta-, or para-divinylbenzenes or mixtures thereof, divinylnaphthalene, divinylanthracene, p-2-propenylstyrene, or p-3-butenylstyrene, and consisting essentially of carbon and hydrogen and substantially free of oxygen, nitrogen, or halogens. Furthermore, bifunctional aromatic vinyl compounds, such as 1,2-bis(vinylphenyl)ethane (abbreviation: BVPE), described in JP 2004-087639 A, can also be used. Among these, various ortho-, meta-, or para-divinylbenzenes or mixtures thereof are preferably used, and a mixture of meta- and para-divinylbenzene is most preferably used. In this specification, these divinylbenzenes are referred to as divinylbenzenes. When divinylbenzenes are used as aromatic polyenes, the vinyl groups contained in the divinylbenzene units are preferred because they have high crosslinking efficiency during curing treatment and facilitate curing. The content of vinyl groups and / or vinylene groups derived from aromatic polyene monomer units contained in the copolymer may be two or more per number-average molecular weight, and the number-average molecular weight of the copolymer per vinyl group and / or vinylene group derived from aromatic polyene monomer unit may be 250 or more and 10,000 or less, preferably 300 or more and 5,000 or less. This value can be obtained by dividing the number-average molecular weight of the copolymer by the number of vinyl groups and / or vinylene groups derived from aromatic polyene monomer units contained per number-average molecular weight.

[0041] Furthermore, in the copolymer, the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units may be 2 to 30, preferably 3 to 20, per number-average molecular weight. The content of vinyl groups and / or vinylene groups may be collectively referred to as the "vinyl group content" below. Because vinyl groups are superior to vinylene groups in terms of crosslinking efficiency, in the present invention, the content of vinyl groups (excluding vinylene groups in this case) derived from the aromatic polyene monomer units is preferably 2 to 30, preferably 3 to 20, per number-average molecular weight. A vinyl group content of 2 or more results in high crosslinking efficiency and a cured product with sufficient crosslink density. Increasing the vinyl group content facilitates improving the mechanical properties of the final cured product at room temperature and high temperatures. The vinyl group content derived from aromatic polyene monomer units (divinylbenzene monomer units) per number-average molecular weight of the copolymer can be determined by comparing the number-average molecular weight (Mn) calculated in terms of standard polystyrene obtained by gel permeation chromatography (GPC), a method known to those skilled in the art, with the composition obtained by H-NMR measurement and / or quantitative C-NMR measurement and the vinyl group content derived from aromatic polyene units. Such methods are obvious and well known to those skilled in the art. Methods described in the patent documents listed in the prior art literature of this specification are also possible. The content of aromatic polyene monomer units in the copolymer is arbitrary, but is preferably less than 40% by mass, more preferably less than 30% by mass, while satisfying the above conditions. At such a content, the number of crosslinking groups is appropriately suppressed, resulting in improved stability during copolymer production and curing.

[0042] The number-average molecular weight of the copolymer is preferably 500 to 30,000, more preferably 500 to 25,000, even more preferably 500 to 15,000, and even more preferably 500 to 12,000. A number-average molecular weight of 500 or more improves the mechanical properties of the composition in the uncured state and provides moderate adhesion, thereby facilitating molding and processing as a thermoplastic resin. A number-average molecular weight of 50,000 or less improves molding processability. A number-average molecular weight of 30,000 or less, or 12,000 or less, is particularly advantageous because it allows the viscosity of a varnish containing the copolymer to be kept below a certain value. A varnish with a viscosity lower than a certain value improves workability and facilitates impregnation of glass fibers and the like with the varnish, improving embeddability in semiconductor devices with uneven surfaces.

[0043] Specific examples of the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer as one embodiment of the present copolymer include one or more members selected from the group consisting of ethylene-norbornene-divinylbenzene copolymer, propylene-norbornene-styrene-divinylbenzene copolymer, 1-hexene-norbornene-styrene-divinylbenzene copolymer, 1-octene-norbornene-styrene-divinylbenzene copolymer, ethylene-norbornene-ethylvinylbenzene-divinylbenzene copolymer, propylene-styrene-norbornene-divinylbenzene copolymer, 1-hexenestyrene-styrene-norbornene-divinylbenzene copolymer, and 1-octene-norbornene-styrene-divinylbenzene copolymer. Further, copolymers in which the above-mentioned norbornene is replaced with dimethanooctahydronaphthalene (DMON), trimethanododecahydroanthracene (TMDA), phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), or methylphenylnorbornene (5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene) are also suitable examples of copolymers of the present invention.

[0044] The α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer of the present invention can be sufficiently cured by being cured alone. Here, "curing alone" refers to adding a peroxide-based, azo-based, or hydrocarbon-based radical initiator as a curing agent in an amount of 1 part by mass or less per 100 parts by mass of the copolymer, and performing a curing process under curing conditions appropriate for the curing agent used (note that the solvent is either substantially removed by drying or the like during curing, or any residual solvent is ignored for purposes of this definition). The degree of curing can be evaluated by the gel fraction, which is greater than 50%, preferably 80% or greater, and particularly preferably 90% or greater. The resulting cured product exhibits excellent low dielectric properties and a glass transition temperature within the range of the present invention. Specifically, the dielectric constant of the cured product may be 2.0 or greater but less than 2.5, and the dielectric dissipation factor may be 0.0002 or greater but less than 0.0006, preferably 0.0002 or greater but less than 0.0005. The storage modulus measured at 25°C can be 1000 MPa or more, and the storage modulus measured at 280°C can be 1 MPa or more, more preferably 5 MPa or more. Here, the gel fraction is a value obtained in accordance with the above-mentioned JIS K6796:1998 (or ASTM D2765-84, which corresponds to ISO 10147:1994, which corresponds to JIS), and the dielectric constant and dielectric dissipation factor are values ​​obtained at 25°C and 40 GHz. The storage modulus at each temperature is obtained by dynamic mechanical analysis (DMA) at a measurement frequency of 1 Hz. Therefore, it is possible to obtain a cured product with a sufficiently high gel fraction by curing a composition containing this copolymer, and the cured product can exhibit excellent low dielectric properties.

[0045] <Compositions containing the copolymer of the present invention> The copolymer of the present invention can be cured alone, but it can also be combined with other materials to form a composition, and the composition can be cured. Here, the other materials can include the following "resin components," "curing agents," "monomers," "solvents," "fillers," "other additives," etc.

[0046] <Resin Component> Any resin component can be used as long as it does not impair the effects of the present invention. Preferably, one or more resins selected from hydrocarbon elastomers, polyether resins, aromatic polyene resins, olefin-aromatic vinyl compound-aromatic polyene copolymers containing no cyclic olefin monomer units, and hard α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymers containing cyclic olefin monomer units can be used. Of these, polyether resins, aromatic polyene resins, and hard α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymers containing cyclic olefin monomer units are more preferred. The amount of resin component is preferably 1 to 500 parts by weight, more preferably 1 to 300 parts by weight, based on 100 parts by weight of the copolymer of the present invention.

[0047] <Hydrocarbon Elastomer> Hydrocarbon elastomers suitable for use in the composition of the present invention may have a number-average molecular weight of 20,000 or more, preferably 30,000 or more. Examples of hydrocarbon elastomers include single or multiple elastomers selected from ethylene-based or propylene-based elastomers, conjugated diene polymers, block or random copolymers of aromatic vinyl compounds and conjugated dienes, and hydrogenated products thereof. Examples of ethylene-based elastomers include ethylene-α-olefin copolymers such as ethylene-octene copolymers and ethylene-1-hexene copolymers, EPR, and EPDM. Examples of propylene-based elastomers include atactic polypropylene, low stereoregular polypropylene, and propylene-α-olefin copolymers such as propylene-1-butene copolymer. These hydrocarbon elastomers may be modified, for example, by introducing functional groups with maleic anhydride or other compounds.

[0048] <Conjugated Diene Polymer> Examples of conjugated diene polymers include polybutadiene and 1,2-polybutadiene. Examples of aromatic vinyl compound-conjugated diene block or random copolymers and their hydrogenated products (hydrogenated products) include SBS, SIS, SEBS, SEPS, SEEPS, and SEEBS. Suitable 1,2-polybutadiene is available, for example, as a product from JSR Corporation, and also available from Nippon Soda Co., Ltd. under the product names of liquid polybutadiene B-1000, 2000, and 3000. Another suitable copolymer containing a 1,2-polybutadiene structure is "Ricon 100" from TOTAL CRAY VALLEY. These conjugated diene polymers and hydrogenated products thereof may be modified, for example, by introducing functional groups with maleic anhydride or other compounds. Among the conjugated diene polymers, conjugated diene copolymers are preferred. Among these conjugated diene copolymers, hydrogenated block copolymers such as SEBS, SEPS, SEEPS, and SEEBS are useful as compatibilizers for the copolymer of the present invention and other resin components. These are available from Asahi Kasei under the trade names Tuftec or SOE-SS, from Kuraray Co., Ltd. under the trade name Septon, and from KRATON under the trade name Kraton.

[0049] <Polyether-Based Resin> Examples of polyether-based resins include polyphenylene ether and polyether. Polyphenylene ethers having functional groups are preferably those in which the molecular terminals are modified with functional groups. Furthermore, when added for the purpose of curing the composition of the present invention, it is preferable that the polyphenylene ether has multiple functional groups in one molecule. For example, modified polyphenylene ether is preferable. Examples of functional groups include radically polymerizable functional groups and epoxy groups, and preferably radically polymerizable functional groups. A vinyl group is preferable as the radically polymerizable functional group. As the vinyl group, one or more of the group consisting of an allyl group, a (meth)acryloyl group, and an aromatic vinyl group are preferable, one or more of the group consisting of a (meth)acryloyl group and an aromatic vinyl group are more preferable, and an aromatic vinyl group is most preferable. In other words, in the composition of the present invention, a bifunctional polyphenylene ether in which both molecular chain terminals are modified with radically polymerizable functional groups is particularly preferable. Examples of such polyphenylene ethers include Noryl (trademark) SA9000 manufactured by SABIC (modified polyphenylene ether having methacryloyl groups at both ends, number average molecular weight 2200) and bifunctional polyphenylene ether oligomer manufactured by Mitsubishi Gas Chemical Company, Inc. (OPE-2St, modified polyphenylene ether having vinylbenzyl groups at both ends, number average molecular weight 1200). Also usable are allylated PPE manufactured by Asahi Kasei Corporation and aromatic polyethers (ELPAC HC-G series) manufactured by JSR Corporation. Of these, the bifunctional polyphenylene ether oligomer (OPE-2St) manufactured by Mitsubishi Gas Chemical Company, Inc. and aromatic polyethers (ELPAC HC-G series) manufactured by JSR Corporation are preferred.

[0050] <Aromatic Polyene Resin> Aromatic polyene resins are resins primarily made from aromatic polyenes, preferably divinylbenzene, and include, for example, divinylbenzene-based reactive hyperbranched copolymers (PDV or ODV) manufactured by Nippon Steel Chemical & Material Co., Ltd. Such copolymers are described, for example, in International Publication No. 2018 / 181842 or in the literature "Synthesis of Polyfunctional Aromatic Vinyl Copolymers and Development of Novel IPN-Type Low Dielectric Loss Materials Using the Same" (Kawabe Masanao et al., Journal of the Institute of Electronics Packaging, Vol. 12, No. 2 (2009) p. 125). The aromatic polyene resin is a resin (copolymer) essentially composed of aromatic polyene monomer units and aromatic monovinyl compound monomer units. More preferably, the aromatic polyene resin does not contain olefin monomer units. The aromatic polyene resin is preferably a resin obtained by cationic polymerization or anionic polymerization. These can be used alone or in any combination of two or more.

[0051] <Another olefin-aromatic vinyl compound-aromatic polyene copolymer not containing a cyclic olefin> The other olefin-aromatic vinyl compound-aromatic polyene copolymer not containing a cyclic olefin that can be used in the present invention is an olefin-aromatic vinyl compound-aromatic polyene copolymer that satisfies all of the following (A) to (E): (A) The number average molecular weight of the copolymer is 500 or more and 100,000 or less; (B) The olefin monomer units are derived from one or more α-olefins selected from α-olefins having from 2 to 20 carbon atoms, and the olefin monomer units do not contain cyclic olefin monomer units; (C) The aromatic vinyl compound monomer units are derived from an aromatic vinyl compound having from 8 to 20 carbon atoms and having one vinyl group or vinylene group in the molecule, and the content of the aromatic vinyl compound monomer units is from 0 to 90 mass%. (D) The aromatic polyene monomer unit is one or more selected from polyenes having 5 to 20 carbon atoms and containing multiple vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer unit is 2 to 30 per number average molecular weight. The content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer unit may be 2 to less than 30 per number average molecular weight. (E) The total of the olefin monomer unit, aromatic vinyl compound monomer unit, and aromatic polyene monomer unit is 100% by mass. Details of the α-olefin, aromatic vinyl compound, and aromatic polyene monomers are as described above. Such copolymers are specifically described in JP 2009-161743 A, WO 2021 / 112087, WO 2021 / 112088, and WO 2022 / 014599. However, as mentioned above, such other copolymers do not contain a cyclic olefin and are therefore distinguishable from the copolymer of the present invention. Among olefin-aromatic vinyl compound-aromatic polyene copolymers not containing a cyclic olefin, copolymers having an aromatic vinyl compound monomer content of 0% by mass or more and 60% by mass or less are particularly soft, and therefore, by blending them with the copolymer of the present invention, the toughness of the resulting cured body can be improved and cracking can be suppressed, which is preferable.

[0052] <Hard α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer containing cyclic olefin> In one embodiment, an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer in an uncured state has a dielectric constant of less than 2.4 at a measurement frequency of 40 GHz, a dielectric dissipation factor of less than 0.0008, and a storage modulus measured at 25°C of 1000 MPa or more, and further satisfies all of the following (1) to (6). This "hard" copolymer can be added to the composition as a "hard" copolymer. Note that this "hard" copolymer is distinguished from the copolymer of the present invention described above by its storage modulus. (1) The number average molecular weight of the copolymer is 500 or more and 100,000 or less. (2) The α-olefin monomer unit is derived from an α-olefin having 2 to 20 carbon atoms. (3) The aromatic vinyl compound monomer unit is derived from an aromatic vinyl compound having 8 to 20 carbon atoms and one vinyl or vinylene group in the molecule. (4) The cyclic olefin monomer units are cyclic olefin monomer units having from 7 to 30 carbon atoms, and the content thereof is from 50 to 99 mass%. (5) The aromatic polyene monomer units are derived from one or more polyenes selected from polyenes having from 5 to 20 carbon atoms and having a plurality of vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units is from 2 to 30 per number average molecular weight. (6) The total of the α-olefin monomer units, cyclic olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100 mass%.

[0053] <Curing Agent> The curing agent that may be included in the present composition may be a known curing agent that has been conventionally used for the polymerization or curing of aromatic polyenes or aromatic vinyl compounds. Examples of such curing agents include radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators, with radical polymerization initiators being preferred. Organic peroxides, azo-based polymerization initiators, and the like are preferred, and can be freely selected depending on the application and conditions. Catalogs listing organic peroxides can be downloaded from the NOF Corporation website, for example, https: / / www.nof.co.jp / product-search / family / 1020001. Organic peroxides are also listed in catalogs from Fujifilm Wako Pure Chemical Industries, Ltd. and Tokyo Chemical Industry Co., Ltd. The curing agents used in the present invention are available from these companies. Furthermore, hydrocarbon-based radical polymerization initiators that do not contain oxygen or nitrogen atoms in their structure, i.e., radical polymerization initiators composed only of carbon and hydrogen atoms, such as 2,3-dimethyl-2,3-diphenylbutane, can also be suitably used. When such hydrocarbon-based radical polymerization initiators are used to produce cured products, they contain no oxygen or nitrogen atoms and have lower dielectric constants and dielectric dissipation factors, further improving the low dielectric properties of the cured products. Azo-based polymerization initiators are also preferred because the nitrogen atoms contained in the polar groups during radical generation are released from the system as nitrogen gas, resulting in cured products with even lower dielectric properties. Known photopolymerization initiators that utilize light, ultraviolet light, or radiation can also be used as curing agents. Examples of curing agents that utilize photopolymerization initiators include photoradical polymerization initiators, photocationic polymerization initiators, and photoanionic polymerization initiators. Such photopolymerization initiators are available, for example, from Tokyo Chemical Industry Co., Ltd. Furthermore, curing using radiation or electron beams themselves is also possible. Crosslinking and curing by thermal polymerization of the raw materials contained in the cured products without the use of a curing agent is also possible.

[0054] There are no particular restrictions on the amount of curing agent used, but generally, an amount of 0.01 to 10 parts by mass per 100 parts by mass of the composition (preferably excluding the curing agent and solvent) is preferred. When using a curing agent such as a peroxide or azo polymerization initiator, the curing treatment should be carried out at an appropriate temperature and time, taking into account its half-life. In this case, the conditions can be determined arbitrarily depending on the curing agent, but a temperature range of approximately 50°C to 250°C is generally appropriate.

[0055] <Monomer> The composition of the present invention may contain any amount of monomer, but preferably 300 parts by weight or less per 100 parts by weight of copolymer. The composition may be substantially free of monomer. If a monomer is contained, the amount is preferably 1 part by weight or more, more preferably 5 parts by weight or more. In particular, when the monomer content is 30 parts by weight or less, the uncured composition is less likely to become viscous, facilitating molding and processing as a thermoplastic resin. Furthermore, when the content of volatile monomers is below a certain level, odor in the uncured state is not a problem. When a solvent is added to the composition to produce a varnish-like product, the monomer is lost as the solvent evaporates during use, which can lead to a problem of a decrease in the actual content of the monomer. Furthermore, when the product is in the form of an uncured sheet, containing a certain amount or less of monomer reduces the change in the monomer content during storage. Monomers suitable for use in the composition of the present invention preferably have a molecular weight of less than 5,000, more preferably less than 1,000, and even more preferably less than 500. Monomers that can be suitably used in the composition of the present invention include the aromatic vinyl compound monomers, the aromatic polyene monomers, the aromatic vinylene monomers described below, and / or the polar monomers described below. Furthermore, fluorene derivatives having an aromatic vinyl group as a functional group, as described in International Publication No. 2024 / 111414, and oligomers having an aromatic vinyl group as a functional group, as described in Japanese Patent Application Laid-Open No. 2024-102859, can also be suitably used as such monomers. Preferred monomers are those that can be polymerized with a radical polymerization initiator, and most preferred are monomers having an aromatic vinyl group as a functional group, the same as the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer of the present invention. Furthermore, BVPE (1,2-bis(vinylphenyl)ethane) described in Japanese Patent Application Laid-Open No. 2003-212941 can also be suitably used.

[0056] <Aromatic Vinylene Monomer> The aromatic vinylene monomer that may be included in the present invention refers to a compound having both a single aromatic ring or multiple condensed aromatic rings having 9 to 30 carbon atoms and a vinylene group. Examples of such aromatic vinylene compounds include indenes, beta-substituted styrenes, acenaphthylenes, etc. Examples of indenes include indene, various alkyl-substituted indenes, and phenyl-substituted indenes. Examples of beta-substituted styrenes include beta-alkyl-substituted styrenes such as beta-methylstyrene, and phenyl-substituted styrenes. Examples of acenaphthylenes include acenaphthylene, various alkyl-substituted acenaphthylenes, and various phenyl-substituted acenaphthylenes. As the aromatic vinylene compound, the above-exemplified compounds may be used alone or in combination of two or more. From the viewpoints of industrial availability and radical polymerizability, acenaphthylene is the most preferred aromatic vinylene compound.

[0057] <Polar Monomer> A polar monomer can be used to impart adhesion to other materials required for the insulating material. Examples of the polar monomer include various maleimides, bismaleimides, maleic anhydride, glycidyl (meth)acrylate, triallyl isocyanurate, tri(meth)acrylic isocyanurate, and trimethylolpropane tri(meth)acrylate. Maleimides and bismaleimides that can be used in the present invention are described, for example, in International Publication No. 2016 / 114287 or Japanese Patent Application Laid-Open No. 2008-291227, and can be purchased from, for example, Daiwa Kasei Co., Ltd. or Designer Molecules Inc. Furthermore, examples of such polar monomers that can be used include maleimide resins "MIR-3000" and "MIR-5000" manufactured by Nippon Kayaku Co., Ltd., and bismaleimide resin "SLK" manufactured by Shin-Etsu Chemical Co., Ltd. These maleimide group-containing compounds may be used as polyaminobismaleimide compounds from the viewpoints of solubility in organic solvents, high-frequency characteristics, high adhesion to conductors, and moldability of prepregs. Polyaminobismaleimide compounds can be obtained, for example, by subjecting a compound having two maleimide groups at its terminals to a Michael addition reaction with an aromatic diamine compound having two primary amino groups in its molecule. To achieve high crosslinking efficiency with a small amount of addition, it is preferable to use a polar monomer having a bifunctional or higher polyfunctional group, such as bismaleimides, triallyl isocyanurate (TAIC), or trimethylolpropane tri(meth)acrylate. The amount of polar monomer that may be contained in the composition is arbitrary, but is preferably 0.1 to 30 parts by weight, more preferably 0.1 to 10 parts by weight, per 100 parts by weight of the copolymer. Using 30 parts by weight or less reduces the dielectric constant and dielectric dissipation factor of the resulting cured product. For example, in a preferred embodiment, the dielectric constant of the cured copolymer is 3.5 or less, and the dielectric dissipation factor is 1.2 x 10. -3 It is possible to reduce it to the following:

[0058] <Solvent> An appropriate solvent may be added to the composition of the present invention as needed. The solvent is used to adjust the viscosity and fluidity of the composition. Volatile solvents are preferred, such as cyclohexane, toluene, ethylbenzene, acetone, and isopropanol. The solvent is used to adjust the viscosity and fluidity of the composition as a varnish. A solvent with a high boiling point at atmospheric pressure, i.e., low volatility, results in a uniform thickness of the applied film, so a solvent with a boiling point of at least a certain level is preferred. A preferred boiling point is 100°C or higher, more preferably 130°C or higher and 300°C or lower, at atmospheric pressure. Solvents suitable for such varnishes include cyclohexane, toluene, xylene, mesitylene, tetralin, acetone, ethylbenzene, limonene, mixed alkanes, mixed aromatic solvents, ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether. In the case of a solvent, the amount used is preferably in the range of 10 to 2,000 parts by mass, more preferably 5 to 500 parts by mass, and even more preferably 10 to 300 parts by mass, per 100 parts by mass of the composition of the present invention. The solvent is preferably removed by a drying treatment or the like before curing the composition.

[0059] <Filler> The composition of the present embodiment may contain a conventionally known filler as needed. As the filler, either an inorganic filler or an organic filler can be used, and the type is not particularly limited. These fillers can be added for the purposes of controlling the thermal expansion coefficient, controlling thermal conductivity, reducing prices, etc., and the amount added can be set appropriately as needed and is not particularly limited. The composition of the present invention can particularly contain a large amount of inorganic filler, and the maximum amount that can be added can reach 2000 parts by mass per 100 parts by mass of copolymer. In particular, when adding an inorganic filler, it is preferable to use a known surface modifier such as a silane coupling agent. In particular, when the objective of the present invention is to achieve a composition with excellent low dielectric constant and low dielectric loss, silica (particularly low-dielectric fused silica or deflagration silica, etc.) or boron nitride (BN) is preferred as the inorganic filler. As such low-dielectric fused silica, for example, those described in WO 2020 / 195205 or WO 2021 / 215519 can be used. From the viewpoint of low dielectric properties, since adding a large amount of filler increases the dielectric constant, preferably less than 500 parts by mass, more preferably less than 400 parts by mass, and even more preferably 100 parts by mass or less per 100 parts by mass of the copolymer may be used. Furthermore, in order to improve and enhance the low dielectric properties (low dielectric constant, low dielectric loss tangent), hollow fillers or fillers with many voids may be added. These may be used alone or in any combination of two or more.

[0060] Alternatively, organic fillers such as high molecular weight polyethylene, ultra-high molecular weight polyethylene, polystyrene, styrene-divinylbenzene copolymer, or fluorine-based resins can be used instead of inorganic fillers. Examples of fluorine-based resins include known fluorine-containing resins such as PTFE (polytetrafluoroethylene) and PFA (perfluoroalkoxyalkane). An example of such a resin is Fluon+ (registered trademark) EA-2000 from AGC. When the melting point or glass transition temperature of the organic filler is lower than the solder reflow temperature of 290°C, it is preferable from the standpoint of heat resistance that the organic filler itself be crosslinked, and it is preferable that it be incorporated in the form of fine particles or powder. These organic fillers can also suppress increases in dielectric constant and dielectric loss tangent.

[0061] On the other hand, by mixing and dispersing a high-dielectric-constant insulating filler having a dielectric constant at 1 GHz of preferably 3 to 10,000, more preferably 5 to 10,000, into the composition of the present invention, it is possible to produce a cured insulating product having a high-dielectric-constant insulating layer with a dielectric constant of preferably 2.5 to 20, more preferably 2.8 to 10, while suppressing an increase in dielectric loss tangent (dielectric loss). Increasing the dielectric constant of a film made from the cured insulating product enables the miniaturization of circuits and the increase in capacitance of capacitors, contributing to the miniaturization of high-frequency electrical components. High-dielectric-constant, low-dielectric-loss-tangent insulating layers are suitable for applications such as capacitors, inductors for resonant circuits, filters, and antennas. Examples of high-dielectric-constant insulating fillers used in the present invention include inorganic fillers or metal particles that have been subjected to an insulating treatment. Specific examples include known high-dielectric-constant inorganic fillers such as barium titanate and strontium titanate. Other examples are specifically described in, for example, JP 2004-087639 A.

[0062] <Other Additives> The composition may further contain one or more selected from a flame retardant and a surface modifier. The composition of the present invention can serve as a matrix for a cured body, and when cured, it has excellent filling properties for other materials. Therefore, the composition contains one or more selected from these fillers, flame retardants, and surface modifiers, and the cured body tends to exhibit impact resistance and toughness even after curing.

[0063] <Flame Retardant> A known flame retardant can be used in the composition of the present invention. From the viewpoint of maintaining a low dielectric constant and a low dielectric loss tangent, preferred flame retardants are known organic phosphorus-based flame retardants such as phosphate esters or condensates thereof, known bromine-based flame retardants, and red phosphorus. Among phosphate esters, compounds having multiple xylenyl groups in the molecule are particularly preferred from the viewpoint of flame retardancy and a low dielectric loss tangent.

[0064] In addition to the flame retardant, antimony compounds such as antimony trioxide, antimony tetraoxide, antimony pentoxide, and sodium antimonate, or nitrogen-containing compounds such as melamine, triallyl-1,3,5-triazine-2,3,4-(1H,3H,5H)-trione, and 2,4,6-trialyloxy-1,3,5-triazine may be added as a flame retardant aid. The total amount of these flame retardants and flame retardant aids is usually preferably 1 to 100 parts by mass per 100 parts by mass of the composition. Furthermore, a polyphenylene ether (PPE) resin with a low dielectric constant and excellent flame retardancy may be used in an amount of 30 to 200 parts by mass per 100 parts by mass of the flame retardant.

[0065] <Surface Modifier> The composition of the present invention may contain various surface modifiers for the purpose of improving adhesion to fillers, copper plates, and wiring. The amount of the surface modifier used per 100 parts by mass of the composition of the present invention other than the surface modifier is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass. Examples of the surface modifier include various silane coupling agents and titanate coupling agents. Various silane coupling agents and titanate coupling agents may be used singly or in combination.

[0066] In the present invention, the flow temperature of the curable resin or composition can be adjusted to suit the purpose and molding method by changing the compounding ratio of the "resin component," "curing agent," "monomer," "solvent," "filler," or "other additives." Specifically, the composition of the present invention can take the form of a product such as a "thermoplastic composition," a "semi-cured state (such as a B-stage sheet)," or a "varnish."

[0067] The composition of the present invention can be obtained by mixing, dissolving or melting one or more of the following: "resin components," "curing agents," "monomers," "solvents," "fillers," and "other additives." In addition, general additives that are added to ordinary resins, such as lubricants, stabilizers, antioxidants, weather resistance agents, ultraviolet absorbers, etc., can be used to the extent that the object of the present invention is not impaired. Any known method can be used for mixing, dissolving or melting these.

[0068] <Thermoplastic composition and molded article thereof> The composition of the present invention uses a copolymer having a molecular weight above a certain level, generally a weight-average molecular weight of about 50,000 or more, and when it contains the specified resin components, it can exhibit the properties of a thermoplastic resin. Therefore, under conditions that do not cause crosslinking, it can be molded into shapes such as sheets, tubes, strips, pellets, etc. in a substantially uncured state using known molding methods for thermoplastic resins. The molded article may be crosslinked (cured) after or during molding.

[0069] A preferred embodiment of the present composition is as follows. Excluding resins that are liquid at room temperature, when the resin component contains a certain proportion or more of one or more resins selected from the hydrocarbon elastomers, polyether resins, olefin-aromatic vinyl compound-aromatic polyene copolymers that do not contain cyclic olefins, and aromatic polyene resins, the composition is also easily molded into a thermoplastic resin in an uncured state. The thermoplastic compositions described above can be molded into various shapes, such as sheets, at or below the active temperature of the curing agent, utilizing their thermoplasticity. These can then be laminated and combined with semiconductor elements, wiring, or substrates as needed, and then heat-cured and bonded.

[0070] The composition of the present invention may be provided as a sheet obtained by molding the composition, heated and melted at a temperature below or equal to the curing agent's working temperature or decomposition temperature, using a known method. Forming into a sheet may be achieved by T-die extrusion, two-roll extrusion, or extrusion lamination onto a substrate film. In this case, the composition's composition, copolymer / monomer mass ratio, or solvent, resin component, and flame retardant are selected and adjusted so that the composition melts below or equal to the curing agent's working temperature or decomposition temperature and becomes solid at or near room temperature. In this case, the sheet is substantially uncured. After various processing and assembly steps, the sheet is finally treated at a temperature and time above the curing agent's working temperature or decomposition temperature to achieve complete curing. This method is a common technique used for ethylene-vinyl acetate resin-based crosslinked sealant sheets for solar cells (photovoltaic power generation devices).

[0071] <Molded Article in a Semi-Cured State (B-Stage Sheet, etc.)> The composition of the present invention can also be formed into a molded article, such as a sheet or tube, in a partially crosslinked state, for example, a state in which a portion of the curing agent contained therein has reacted and been semi-cured (so-called B-stage state). Here, the term "semi-cured state" is defined as a state in which the proportion of gel content as a resin component in the composition of the present invention is greater than 20% by mass and not more than 80% by mass, independently of the definition of the uncured state. The gel content is a value obtained by measurement in accordance with JIS K6796:1998. For example, by employing multiple curing agents and / or curing conditions with different curing temperatures, the composition can be semi-cured, and the melt viscosity and fluidity can be controlled to achieve a B-stage state. That is, the curable resin or composition can be molded into an easily handleable B-stage sheet by a first curing step (partial curing), which can then be laminated and pressure-bonded to an electronic device or substrate, followed by a second curing step (complete curing) to form the final shape. In this case, the composition, i.e., the copolymer / monomer mass ratio, is selected, and if necessary, a solvent, resin component, and flame retardant are added. The composition further contains a curing agent such as a peroxide, which is partially cured and adjusted to a sheet shape (B-stage state). After molding and assembling the device, the composition can be heated under pressure to fully cure. Known methods can be used to partially cure the composition. For example, peroxides with different decomposition temperatures are used in combination, and the mixture is treated for a predetermined time at a temperature at which only one of the peroxides is substantially active to obtain a semi-cured sheet. Finally, the mixture is treated for a sufficient time at a temperature at which all of the curing agents are active to fully cure the sheet.

[0072] Furthermore, the molded article may be a sheet. The sheet may be uncured (semi-cured) to the extent that it can maintain its sheet shape, or may be fully cured. The degree of curing of the composition can be quantitatively measured by known dynamic mechanical analysis (DMA).

[0073] <Varnish-like Composition and Molded Articles Thereof> The composition of the present invention can also be made into a viscous liquid varnish by adjusting its composition and blending ratio. For example, a sufficient amount of solvent and / or an appropriate amount of liquid monomer can be used to make the composition into a varnish. When used as a varnish, it is preferable to add an appropriate solvent to the composition of the present invention. The solvent is used to adjust the viscosity and fluidity of the composition as a varnish. A solvent with a high boiling point at atmospheric pressure, i.e., low volatility, contributes to a uniform thickness of the applied film, so a solvent with a boiling point above a certain level is preferred. A preferred boiling point is approximately 110°C or higher and 300°C or lower at atmospheric pressure. Examples of solvents suitable for such varnishes include toluene, xylene, mesitylene, ethylbenzene, limonene, ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether. The amount of the solvent used is preferably in the range of 10 to 2,000 parts by mass per 100 parts by mass of the composition of the present invention.

[0074] The varnish can be applied to or impregnated into a substrate, and the solvent or the like can be removed by drying or the like to produce an uncured or semi-cured molded article. This molded article generally has the form of a sheet, film, or tape. In this embodiment, the obtained uncured or semi-cured molded article is cured.

[0075] <Curing> The composition can be cured by a known method, taking into consideration the curing conditions (temperature, time, pressure) of the curing agent contained therein. When the curing agent used is a peroxide, the curing conditions can be determined by taking into consideration the half-life temperature and the like disclosed for each peroxide.

[0076] <Cured Product of Composition> The dielectric constant and dielectric loss tangent of the cured product obtained from the composition of the present invention are measured by a known resonator method. In this specification, the resonator method is performed at a measurement frequency of 40 GHz. The dielectric constant of the cured product may be 3.5 or less, preferably 3.5 to 2.0, and particularly preferably 3.0 to 2.0. The dielectric loss tangent of the cured product may be 0.0015 or less, 0.0002 to 0.0015, and preferably 0.0002 to 0.0012. The volume resistivity of the cured product is preferably 1×10 15 Ω·cm or more. These values ​​are preferred for use as an electrical insulating material for high frequencies of, for example, 3 GHz or more. Because the copolymer used in the composition of the present invention is relatively soft and has excellent tensile elongation, a cured product obtained from a composition using the copolymer exhibits sufficient mechanical properties, relatively high impact resistance, and can adapt to the thermal expansion of a substrate. That is, the storage modulus of the cured product of the present invention measured at room temperature (25°C) is preferably 30 GPa or less and 0.1 GPa or more, more preferably less than 30 GPa and 0.1 GPa or more, and even more preferably 1 GPa or more and 20 GPa or less. Furthermore, the storage modulus measured at a high temperature (280°C) is preferably 1 MPa or more and 1 GPa or less, more preferably 5 MPa or more and 1 GPa or less, and even more preferably 10 MPa or more and 1 GPa or less. Those skilled in the art can determine the formulation of a composition having the above physical property parameters and prepare a cured product by referring to the information described in this specification and publicly known documents. The cured product obtained from the composition of the present invention can exhibit heat resistance and mechanical properties at high temperatures sufficient for practical use, even under conditions in which the monomer in the composition and the aromatic polyene as a component of the monomer are kept below a certain percentage.

[0077] <General Uses of the Composition> The composition of the present invention can be used as a material for base materials / substrates such as single-layer or multilayer printed circuit boards, flexible printed circuit boards, so-called single-layer or multilayer CCL (copper clad laminate) boards, single-layer or multilayer FCCL (flexible copper clad laminate) boards, and resin-coated copper (RCC). It can also be used as various electrical insulating materials for wiring, preferably high-frequency signal wiring, such as coverlays, high-frequency transmission circuits, antennas, solder resists, build-up materials, interlayer insulating materials, bonding sheets, interlayer adhesives, and bump sheets for flip-chip bonders.

[0078] In another aspect, the present invention provides an electrical insulating material comprising an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, which, as a cured product, has a dielectric constant of 2.0 or more and 3.5 or less, and a dielectric dissipation factor of 0.0015 or less, preferably 0.0012 or less, measured at 23°C and 40 GHz.

[0079] In one embodiment of the present invention, there is also provided a method for producing the copolymer. The production method includes copolymerizing the monomers of an α-olefin, a cyclic olefin, an aromatic vinyl compound, and an aromatic polyene by coordination polymerization. In another embodiment, there is also provided a method for producing a cured product, which includes polymerizing the copolymer using a radical polymerization initiator that does not contain oxygen or nitrogen atoms in its structure and is composed only of carbon and hydrogen atoms.

[0080] Coordination polymerization is a polymerization method using a coordination polymerization catalyst consisting of a transition metal compound and a co-catalyst. As the transition metal compound, transition metal compounds containing zirconium, hafnium, titanium, iron, nickel, cobalt, and palladium are preferred. In particular, for copolymerizing cyclic olefin monomers, transition metal compounds containing zirconium, titanium, nickel, iron, and palladium are preferred. The most preferred coordination polymerization catalyst is a coordination polymerization catalyst consisting of a transition metal compound represented by the following general formula (1) and a co-catalyst. More preferably, the production method may include a step of copolymerizing each of the monomers of an α-olefin, a cyclic olefin, an aromatic vinyl compound (if included), and an aromatic polyene using a polymerization catalyst consisting of a transition metal compound represented by the following general formula (1) and a co-catalyst:

[0081] General formula (1) In the above formula, A and B are each independently a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzoindenyl group, an unsubstituted or substituted cyclopentadienyl group, or an unsubstituted or substituted indenyl group. Y is bonded to A and B and is a methylene group, silylene group, ethylene group, germylene group, or boron residue having hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as an additional substituent. The substituents may be different or the same. Y may also have a cyclic structure. Most preferably, Y is a methylene group having a bond to A and B and having hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as an additional substituent. X is hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylaryl group having 8 to 12 carbon atoms, a silyl group having a hydrocarbon substituent having 1 to 4 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamido group having an alkyl substituent having 1 to 6 carbon atoms. M is a transition metal, and may be preferably zirconium, hafnium, or titanium.

[0082] To obtain a copolymer having a relatively low molecular weight and a low viscosity when made into a varnish, preferably, A and B in the above general formula (1) may each independently be a group selected from an unsubstituted or substituted cyclopentadienyl group or an unsubstituted or substituted indenyl group, and it is particularly preferable to use a transition metal compound having both an unsubstituted or substituted cyclopentadienyl group and an unsubstituted or substituted indenyl group. To obtain a copolymer having a high aromatic polyene content, i.e., a copolymer having a high number of vinyl groups and / or vinylene groups derived from aromatic polyene monomer units per number average molecular weight, it is preferable to use a transition metal compound having at least one group selected from an unsubstituted or substituted indenyl group or an unsubstituted or substituted benzoindenyl group. When the copolymer has a high aromatic polyene content, it is possible to increase the crosslink density of the cured product obtained by curing, and for example, a cured product having a storage modulus of 5 MPa or more measured at 280°C can be obtained.

[0083] The cocatalyst in the polymerization catalyst of the present invention can be a known cocatalyst used in combination with a transition metal compound. Preferred examples of such cocatalysts include aluminum compounds and boron compounds. Alumoxanes such as methylaluminoxane (also referred to as methylalumoxane or MAO) are preferably used as the aluminum compound. Alternatively, alkylaluminums such as triisobutylaluminum and triethylaluminum may be used. Examples of such cocatalysts include the cocatalysts and alkylaluminum compounds described in EP 0872492A2, JP 11-130808 A, JP 9-309925 A, WO 00 / 20426 A, EP 0985689A, and JP 6-184179 A.

[0084] Examples of the boron compound (boron-containing promoter) include trispentafluorophenylborane, triphenylcarbenium tetrakis(pentafluorophenyl)borate {trityltetrakis(pentafluorophenyl)borate}, lithium tetrakis(pentafluorophenyl)borate, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, tri(n-butyl)ammonium tetra(p-tolyl)phenylborate, tri(n-butyl)ammonium tetra(p-ethylphenyl)borate, tri(n-butyl)ammonium tetra(pentafluorophenyl)borate, trimethylammonium tetra(p-tolyl)borate, trimethylammonium tetrakis-3,5-dimethylphenylborate, triethylammonium tetra tetrakis-3,5-dimethylphenylborate, tributylammonium tetrakis-3,5-dimethylphenylborate, tributylammonium tetrakis-2,4-dimethylphenylborate, anilinium tetrakispentafluorophenylborate, N,N'-dimethylanilinium tetraphenylborate, N,N'-dimethylanilinium tetrakis(p-tolyl)borate, N,N'-dimethylanilinium tetrakis(m-tolyl)borate, N,N'-dimethylanilinium tetrakis(2,4-dimethylphenyl)borate, N,N'-dimethylanilinium tetrakis(3,5-dimethylphenyl)borate, N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N'-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N'-2,4,5-pentamethylanilinium tetraphenylborate, N,N'-2,4,Examples of suitable tetraphenylborate include 5-pentaethylanilinium tetraphenylborate, di-(isopropyl)ammonium tetrakispentafluorophenylborate, di-cyclohexylammonium tetraphenylborate, triphenylphosphonium tetraphenylborate, tri(methylphenyl)phosphonium tetraphenylborate, tri(dimethylphenyl)phosphonium tetraphenylborate, triphenylcarbenium tetrakis(p-tolyl)borate, triphenylcarbenium tetrakis(m-tolyl)borate, triphenylcarbenium tetrakis(2,4-dimethylphenyl)borate, triphenylcarbenium tetrakis(3,5-dimethylphenyl)borate, tropylium tetrakispentafluorophenylborate, tropylium tetrakis(p-tolyl)borate, tropylium tetrakis(m-tolyl)borate, tropylium tetrakis(2,4-dimethylphenyl)borate, and tropylium tetrakis(3,5-dimethylphenyl)borate, but are not particularly limited to these. Although boron-containing cocatalysts in which the fluorine-substituted aromatic group is a phenyl group have been exemplified herein, boron-containing cocatalysts having a fused aromatic group such as a fluorine-substituted naphthyl group can also be preferably used. Among these, preferred boron-containing cocatalysts are those having boron and a fluorine-substituted aromatic group bonded thereto. Examples thereof include, but are not limited to, trispentafluorophenylborane, triphenylcarbenium tetrakis(pentafluorophenyl)borate {trityl tetrakis(pentafluorophenyl)borate}, lithium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetra(pentafluorophenyl)borate, tropylium tetrakispentafluorophenylborate, and N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate. Particularly preferred are triphenylcarbenium tetrakis(pentafluorophenyl)borate {trityl tetrakis(pentafluorophenyl)borate} and N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate is used. These most preferred boron-containing cocatalysts are sometimes referred to as TRI-FABA or TRI-FAB, and DAN-FABA or DAN-FAB, respectively, and can be purchased from Tosoh Finechem Co., Ltd. or Kanto Chemical Co., Ltd.

[0085] The co-catalyst is used in an aluminum atom / transition metal atomic ratio relative to the metal of the transition metal compound of 0.1 to 100,000, preferably 10 to 10,000. A ratio of 0.1 or more can effectively activate the transition metal compound, while a ratio of 100,000 or less is economically advantageous. The transition metal compound and co-catalyst may be mixed and prepared outside of a polymerization facility, or may be mixed inside the facility during polymerization.

[0086] In particular, the aluminum atom / transition metal atomic ratio of a promoter such as alumoxane relative to the metal of the transition metal compound is preferably 0.1 to 100,000, and more preferably 10 to 10,000. A ratio of 0.1 or more can effectively activate the transition metal compound, and a ratio of 100,000 or less is economically advantageous. When a boron compound is used as the promoter, the boron atom / transition metal atomic ratio is preferably 0.1 to 100, more preferably 0.1 to 10, and most preferably in the range of 0.8 to 1.2. A ratio of 0.1 or more can effectively activate the transition metal compound, and a ratio of 100 or less is economically advantageous.

[0087] In a preferred embodiment, a boron compound is required as a co-catalyst, and an aluminum compound may be used as needed. The use of a boron compound as a co-catalyst can reduce the amount of metal components, such as aluminum derived from the aluminum compound, contained in the final copolymer, and can reduce the dielectric constant and dielectric loss tangent of the final uncured copolymer, or the dielectric constant and dielectric loss tangent of the single cured product or composition, to particularly preferred ranges. For example, the dielectric constant of the uncured copolymer can be less than 2.3, and the dielectric loss tangent can be less than 0.0004. Furthermore, when a boron compound is used as a co-catalyst, the dielectric constant of the final cured product of the copolymer can be less than 2.3, and the dielectric loss tangent can be less than 0.0004.

[0088] In one embodiment, an uncured α-olefin-cycloolefin-aromatic polyene copolymer or α-olefin-cycloolefin-aromatic vinyl compound-aromatic polyene copolymer can be provided, having a total metal content derived from the catalyst and co-catalyst of 1500 ppm or less. Here, the metal content derived from the catalyst and co-catalyst is defined as the sum of the respective contents of the transition metal elements (as described above) used in the catalyst and the boron and / or aluminum derived from the boron compound and / or aluminum compound used in the co-catalyst, and can be defined as the sum of the respective elemental contents of zirconium, hafnium, titanium, iron, nickel, palladium, cobalt, boron, and aluminum. Particularly preferably, the metal derived from the catalyst may be zirconium, and the metal derived from the co-catalyst may be aluminum and boron, and the metal content derived from the catalyst and co-catalyst may be the sum of the respective contents of zirconium, aluminum, and boron. Note that, in this specification, boron is included in the category of metal. An uncured α-olefin-cyclic olefin-aromatic polyene copolymer or α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer having a total metal content of 1500 ppm or less can exhibit one or more of the following properties: a dielectric constant at a measurement frequency of 40 GHz of less than 2.4, a dielectric dissipation factor at a measurement frequency of 40 GHz of less than 0.0007, and a storage modulus measured at 25°C of 1000 MPa or more.

[0089] The present invention will be described below with reference to examples, but the present invention should not be construed as being limited to the following examples.

[0090] The copolymers obtained in the synthesis examples were analyzed by the following means. The contents of ethylene, 1-octene, cyclic olefin, styrene, and ethylvinylbenzene in the copolymer, as well as the content of vinyl group units derived from divinylbenzene, were determined by the following methods: 1 H-NMR measurement and quantitative mode 13 C-NMR measurement was performed, and the determination was performed using a known method based on the area intensity of the obtained peak. The sample was dissolved in deuterated 1,1,2,2-tetrachloroethane, and the measurement was performed at 80 to 130°C.

[0091] The molecular weight was determined as a number average molecular weight (Mn) converted to standard polystyrene using GPC (gel permeation chromatography) under the following conditions:

[0092] Column: Three TSK-GEL Multipore HXL-M φ7.8 × 300 mm (manufactured by Tosoh Corporation) connected in series. Column temperature: 40°C. Solvent: THF. Flow rate: 1.0 ml / min. Detector: RI detector.

[0093] <Viscosity> The viscosity of the copolymer obtained in each example was determined as follows: A 50% by mass toluene solution of each copolymer was prepared, and the viscosity was measured at 25°C using a rotational rheometer (MCR302: manufactured by Anton Paar) at a shear rate of 1 sec. -1 The value of was used.

[0094] <Gel content> The gel content was determined as boiling toluene insoluble matter according to ASTM D2765-84.

[0095] <Dielectric constant and dielectric loss (dielectric loss tangent)> The dielectric constant and dielectric loss tangent at 40 GHz were measured at 23°C using a cavity resonator perturbation method (Agilent Technologies 8722ES network analyzer, Keysight Technologies 40 GHz split cylinder resonator) using a 0.2 mm x 30 mm x 40 mm sample cut out from the sheet. Measurements were performed for both the uncured and cured states. The dielectric constant and dielectric loss tangent at 10 GHz were measured at 23°C using a cavity resonator perturbation method (Agilent Technologies 8722ES network analyzer, Keysight Technologies 10 GHz split cylinder resonator) using a 0.2 mm x 60 mm x 70 mm sample cut out from the cured sheet. The dielectric constant and dielectric loss tangent at 77 GHz were measured at 23°C using an open resonator method (Agilent Technologies 8722ES Network Analyzer, Keysight Technologies Fabry-Perot Resonator) using a 0.2 mm × 60 mm × 70 mm sample cut out from the cured sheet.

[0096] <Measurement of storage modulus> Using a dynamic viscoelasticity measuring device (TA Instruments, formerly Rheometrics RSA-G2), measurements were taken at a frequency of 1 Hz in a nitrogen atmosphere while the temperature was raised from 20°C, and the storage modulus at 25°C and 280°C were measured. Measurement samples (4 mm x 35 mm) were cut out from a film approximately 0.2 mm thick and measured, and the storage modulus was measured in both the uncured and cured states. The glass transition temperature was also determined from the peak top temperature of the loss tangent (tan δ) in the uncured state. The main measurement parameters involved in the measurement were as follows: Measurement frequency 1 Hz, Heating rate 3°C / min, Sample measurement length 10 mm, Strain 0.1%

[0097] <Method of determining glass transition temperature by DSC method> A differential scanning calorimeter (METTLER TOLEDO DSC 3+) was used. As a pretreatment, the temperature was raised from 25°C to 100°C under a nitrogen atmosphere, and then cooled to -60°C. Thereafter, the temperature was raised from -60°C under a nitrogen atmosphere, and measurements were taken to determine the glass transition temperature (Tg). The midpoint glass transition temperature was used as the glass transition temperature here. The main measurement parameters related to the measurement were as follows: Heating rate: 3°C / min Nitrogen flow rate: 30mL / min Sample amount: 5mg

[0098] <Quantification of Metal Content in Copolymer> The metal content (in the example below, the content of transition metal elements used in the metal catalyst, and the content of boron and aluminum used in the cocatalyst) was measured as follows. Furthermore, the contents of hafnium, titanium, iron, nickel, cobalt, and palladium were also quantified. Measurements were performed using ICP atomic emission spectrometry under the following conditions in accordance with JIS K 0116:2014. 0.5 g of the composition to be measured was weighed into a platinum crucible and incinerated on a hot plate, an electric stove, and an electric furnace (gradually heated to 600°C). 0.5 ml of HCl (1+1) (i.e., a 1:1 mixture of hydrochloric acid and water by volume) and ultrapure water were added to the residue, dissolved by heating, and then the volume was adjusted to 5 ml to form the test solution. Quantitative analysis was performed using ICP atomic emission spectrometry (using an Agilent 5110VDV).

[0099] Comparative Example 1: Copolymer Production CP-1 The raw material divinylbenzene (DVB) was "DVB-810" (liquid at room temperature, a mixture of meta and para isomers containing 81% by mass of divinylbenzene, with the remainder being ethylvinylbenzene), manufactured by Nippon Steel Chemical & Material Co., Ltd. A 10 L polymerization vessel equipped with a heating and cooling jacket and a stirrer was used. First, the atmosphere inside the thoroughly dried polymerization vessel was purged with nitrogen, and 1.2 kg of toluene, 2.1 kg of styrene, 200 g of 1-octene, 825 g of pure norbornene (75% by mass toluene solution), and 405 g of pure divinylbenzene were charged, and approximately 300 L of dry nitrogen was bubbled in at an internal temperature of 50°C. The atmosphere inside the polymerization vessel was then purged with ethylene gas, and 20 mmol of TIBA (manufactured by Kanto Chemical Co., Inc.) was added and stirred. The internal temperature was stabilized at 60°C, and the internal pressure of the polymerization vessel was increased to 0.35 MPaG (gauge) by supplying ethylene and stabilized. Then, a catalyst solution prepared by stirring and dissolving 260 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 310 g of a toluene solution containing 210 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride (structure: see formula (2) below) as a catalyst and 2.5 mmoles of triisobutylaluminum was added from a catalyst tank installed above the polymerization vessel to initiate polymerization. Ethylene consumed in the polymerization was gradually replenished, and polymerization was continued while maintaining the internal temperature at 60°C and the internal pressure at 0.35 MPaG. After about 1 hour of polymerization, when the ethylene consumption reached 250 g, the ethylene gas in the polymerization vessel was discharged and the pressure was returned to normal, and 60 g of isopropanol as a polymerization terminator was added to the polymerization vessel to terminate the polymerization. The resulting polymerization solution was concentrated under reduced pressure to obtain CP-1, an ethylene-styrene-divinylbenzene-norbornene-1-octene copolymer.

[0100] Formula (2)

[0101] Example 1 Production of Copolymer P-1 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 1.3 kg, 2.4 kg, 405 g (net), 450 g (net), and 300 g, respectively, of 1-octene. Polymerization was carried out using a catalyst solution prepared by stirring and dissolving 170 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 210 g of a toluene solution containing 140 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.7 mmoles of triisobutylaluminum. The polymerization was terminated when the amount of ethylene consumed reached 250 g, yielding an ethylene-styrene-divinylbenzene-norbornene-1-octene copolymer P-1.

[0102] Example 2 Production of Copolymer P-2 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 2 kg, 2.3 kg, 490 g (net), 230 g (net), and 200 g, respectively, of 1-octene. Polymerization was carried out using a catalyst solution prepared by stirring and dissolving 130 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 160 g of a toluene solution containing 110 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.3 mmoles of triisobutylaluminum. The polymerization was terminated when the amount of ethylene consumed reached 250 g, yielding an ethylene-styrene-divinylbenzene-norbornene-1-octene copolymer P-2.

[0103] Example 3 Production of Copolymer P-3 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 2.5 kg, 2 kg, and 490 g (net), respectively, of pure divinylbenzene and 230 g of pure norbornene, and the catalyst solution was changed to 170 g of a toluene solution containing 120 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.4 mmoles of triisobutylaluminum, to which 140 micromoles of tritylium tetrakis(pentafluorophenyl)borate was dissolved with stirring. Polymerization was terminated when the amount of ethylene consumed reached 250 g, yielding an ethylene-styrene-divinylbenzene-norbornene copolymer P-3.

[0104] Example 4 Production of Copolymer P-4 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 2 kg, 2 kg, and 230 g, respectively, of pure divinylbenzene, norbornene, and 1-octene, respectively. Polymerization was carried out using a catalyst solution prepared by stirring and dissolving 140 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 170 g of a toluene solution containing 120 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.4 mmoles of triisobutylaluminum. The polymerization was terminated when the amount of ethylene consumed reached 250 g, yielding an ethylene-styrene-divinylbenzene-norbornene-1-octene copolymer P-4.

[0105] Example 5 Production of Copolymer P-5 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 1.5 kg, 3 kg, 490 g (net), and 230 g (net), respectively. Polymerization was carried out using a catalyst solution prepared by dissolving 150 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 170 g of a toluene solution containing 120 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.4 mmoles of triisobutylaluminum with stirring, and the polymerization was terminated when the amount of ethylene consumed reached 250 g, thereby obtaining an ethylene-styrene-divinylbenzene-norbornene copolymer P-5.

[0106] Example 6 Production of Copolymer P-6 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene used were changed to 1.5 kg, styrene to 3 kg, divinylbenzene to 490 g in pure form, and norbornene to 230 g in pure form. Polymerization was carried out using a catalyst solution obtained by dissolving 100 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 120 g of a toluene solution containing 80 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1 millimole of triisobutylaluminum with stirring, and the polymerization was terminated when the amount of ethylene consumed reached 375 g, thereby obtaining an ethylene-styrene-divinylbenzene-norbornene copolymer P-6.

[0107] Example 7 Production of Copolymer P-7 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 2.3 kg, 2 kg, 490 g (net), and 405 g (net), respectively. Polymerization was carried out using a catalyst solution prepared by dissolving 120 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 140 g of a toluene solution containing 100 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.1 mmoles of triisobutylaluminum with stirring. The polymerization was terminated when the amount of ethylene consumed reached 250 g, yielding an ethylene-styrene-divinylbenzene-norbornene copolymer P-7.

[0108] Example 8 Production of Copolymer P-8 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 2.5 kg, 2 kg, and 730 g (net), respectively, of pure divinylbenzene and 230 g of pure norbornene, respectively. Polymerization was carried out using a catalyst solution prepared by dissolving 180 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 215 g of a toluene solution containing 150 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.7 mmoles of triisobutylaluminum with stirring, and the polymerization was terminated when the amount of ethylene consumed reached 250 g, yielding an ethylene-styrene-divinylbenzene-norbornene copolymer P-8.

[0109] Example 9: Production of copolymer P-9 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 2.6 kg, 2 kg, and 730 g (net), respectively, of pure divinylbenzene and 150 g of pure norbornene, and the catalyst solution was changed to 215 g of a toluene solution containing 125 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.5 mmoles of triisobutylaluminum, to which 150 micromoles of tritylium tetrakis(pentafluorophenyl)borate was dissolved with stirring. Polymerization was terminated when the amount of ethylene consumed reached 250 g, yielding an ethylene-styrene-divinylbenzene-norbornene copolymer P-9.

[0110] Example 10: Production of copolymer P-10 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene, styrene, divinylbenzene, and norbornene were changed to 1.6 kg, 3 kg, 490 g (net), and 150 g (net), respectively. Polymerization was carried out using a catalyst solution prepared by dissolving 190 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 230 g of a toluene solution containing 160 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.9 mmoles of triisobutylaluminum with stirring. The polymerization was terminated when the amount of ethylene consumed reached 250 g, yielding an ethylene-styrene-divinylbenzene-norbornene copolymer P-10.

[0111] Example 11: Production of copolymer P-11 Polymerization was carried out in the same manner as in the synthesis of CP-1, except that the internal pressure of the polymerization vessel was changed to 0.50 MPaG (gauge), the amounts of toluene used were changed to 2.5 kg, the amount of styrene used to 2 kg, the amount of divinylbenzene used to 490 g in pure form, and the amount of norbornene used to 225 g in pure form, and the catalyst solution was changed to 230 g of a toluene solution containing 160 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.9 mmoles of triisobutylaluminum, to which 190 micromoles of tritylium tetrakis(pentafluorophenyl)borate was dissolved with stirring, and the polymerization was terminated when the amount of ethylene consumed reached 250 g, thereby obtaining an ethylene-styrene-divinylbenzene-norbornene copolymer P-11.

[0112] Example 12 Production of Copolymer P-12 Polymerization was carried out in the same manner as in the synthesis of CP-1, except that the internal temperature of the polymerization vessel was changed to 90°C, the amounts of toluene used were changed to 3.5 kg, the amount of styrene used to 1.6 kg, the amount of divinylbenzene used to 330 g in net terms, and the amount of norbornene used to 150 g in net terms. The catalyst was changed to a catalyst solution prepared by dissolving 65 micromoles of tritylium tetrakis(pentafluorophenyl)borate with stirring in 20 g of a toluene solution containing 50 micromoles of rac-diphenylmethylene(1-indenyl)(cyclopentadienyl)zirconium dichloride (structure: see formula (3) below) and 1.0 mmol of triisobutylaluminum, and the polymerization was terminated when the amount of ethylene consumed reached 188 g, thereby obtaining an ethylene-styrene-divinylbenzene-norbornene copolymer P-12.

[0113] Formula (3)

[0114] Example 13 Production of Copolymer P-13 Polymerization was carried out in the same manner as in the synthesis of CP-1, except that the internal temperature of the polymerization vessel was changed to 90°C, the amounts of toluene used were changed to 3.7 kg, the amount of styrene used to 1.6 kg, the amount of divinylbenzene used to 160 g in pure form, and the amount of norbornene used to 150 g in pure form, and the catalyst was changed to a catalyst solution prepared by dissolving 60 micromoles of tritylium tetrakis(pentafluorophenyl)borate with stirring in 20 g of a toluene solution containing 46 micromoles of rac-diphenylmethylene(1-indenyl)(cyclopentadienyl)zirconium dichloride and 0.9 mmoles of triisobutylaluminum, and the polymerization was terminated when the amount of ethylene consumed reached 188 g, thereby obtaining an ethylene-styrene-divinylbenzene-norbornene copolymer P-13.

[0115] Example 14 Production of Copolymer P-14 Polymerization was carried out in the same manner as in the synthesis of CP-1, except that the internal temperature of the polymerization vessel was changed to 90°C, the amounts of toluene used were changed to 3.8 kg, the amount of styrene used to 1.6 kg, the amount of divinylbenzene used to 80 g in pure form, and the amount of norbornene used to 150 g in pure form, and the catalyst was changed to a catalyst solution prepared by dissolving 80 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 30 g of a toluene solution containing 65 micromoles of rac-diphenylmethylene(1-indenyl)(cyclopentadienyl)zirconium dichloride and 1.3 mmoles of triisobutylaluminum with stirring, and the polymerization was terminated when the amount of ethylene consumed reached 188 g, thereby obtaining an ethylene-styrene-divinylbenzene-norbornene copolymer P-14.

[0116] Example 15: Production of copolymer P-15 The same procedure as in the synthesis of CP-1 was carried out, except that the internal temperature of the polymerization vessel was changed to 90°C, the amounts of toluene used were changed to 3.3 kg, the amount of styrene used to 1.5 kg, the amount of divinylbenzene used to 240 g in net terms, and the amount of norbornene used to 230 g in net terms. The catalyst was changed to a catalyst solution prepared by dissolving 50 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 20 g of a toluene solution containing 40 micromoles of rac-diphenylmethylene(1-indenyl)(cyclopentadienyl)zirconium dichloride and 0.8 mmoles of triisobutylaluminum with stirring, and polymerization was terminated when the amount of ethylene consumed reached 313 g, thereby obtaining an ethylene-styrene-divinylbenzene-norbornene copolymer P-15.

[0117] Because CP-1 and P-1 to P-15 obtained in each example contained small amounts of residual monomer and solvent, the solution was diluted with toluene and poured in small amounts into a sufficiently large amount of methanol and stirred. The precipitated polymer was filtered and dried at room temperature under vacuum for 24 hours to obtain a purified polymer. The composition and molecular weight of the resulting CP-1 and P-1 to P-15 are shown in Table 1. The purified polymer was redissolved in toluene using a vial and a magnetic stirrer, and 500 ppm each of 4-tert-butylcatechol (TBC) and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyltoluene (TEMPOL) based on the pure polymer were added to prepare a 50% by mass toluene solution (varnish). The viscosity of the resulting 50% by mass toluene solution (varnish) of CP-1 and P-1 to P-15 is shown in Table 1. A mold made from a silicone rubber sheet (frame length 7 cm, width 7 cm, thickness 1 mm) was placed on a smooth Teflon® sheet, and the varnish was poured into it and dried in a vacuum dryer at 80°C for at least 10 hours. The silicone rubber mold was then removed and a SUS mold (frame length 11 cm, width 11 cm, thickness 0.2 mm) was placed in place. The mold was then pressed in a press at 200°C for 3 minutes under a load of 5 MPa. The Teflon® sheet and SUS mold were removed to obtain an uncured sheet. The sheet was then cut into small pieces and its gel content was measured. The gel content measurement results confirmed that the sheet was in an uncured state. The glass transition temperature of the sheet was measured using DSC. The viscoelasticity spectrum (DMA) of the sheet was measured to determine the storage modulus at 25°C. The dielectric properties of the sheet were measured at 23°C and 40 GHz. These results are shown in Table 1. Note that the amounts in the following tables are in parts by mass unless otherwise specified. Compared with copolymer CP-1, copolymers P-1 to P-15 of the present invention exhibited a low glass transition temperature, a low storage modulus (25°C), and sufficiently low dielectric constants and dielectric loss tangents in an uncured state, and thus exhibited flexibility and dielectric properties that satisfy the requirements of the present invention.

[0118]

[0119]

[0120] Example 16: Preparation of Cured Sheet Similar to the method described above, a 50% by weight toluene solution (varnish) was prepared using P-1 (ethylene-styrene-divinylbenzene-norbornene-1-octene copolymer). Furthermore, 0.75 parts by weight of curing agent VR-110 was added per 100 parts by weight of the copolymer, dissolved, and mixed by stirring to obtain a varnish-like composition (Table 2). A mold (frame length 7 cm, width 7 cm, thickness 1 mm) made from a silicone rubber sheet was placed on a smooth Teflon (registered trademark) sheet, and the varnish was poured into the mold and dried at 80°C for 10 hours or more in a vacuum dryer. The silicone rubber mold was then removed and a stainless steel mold (frame length 11 cm, width 11 cm, thickness 0.2 mm) was installed. The mixture was then pressed under a load of 10 MPa at 120°C for 30 minutes, 150°C for 30 minutes, and then 200°C for 120 minutes. The Teflon sheet and SUS mold were then removed to obtain a cured sheet. The gel fraction, storage modulus (at 25°C and 280°C), dielectric constant and dielectric loss tangent (all measured at 23°C and 40 GHz) of the resulting cured sheet were determined.

[0121] Examples 17 to 34: Preparation of Cured Sheets Cured sheets were obtained using P-2 to P-15, respectively, in the same manner as in Example 16, and physical properties were determined in the same manner. However, in Examples 28, 30, and 32 to 34, Perbutyl P was added as the curing agent in an amount of 0.05 parts by mass based on 100 parts by mass of the copolymer. In Example 19, 2,3-dimethyl-2,3-diphenylbutane was added as the curing agent in an amount of 0.75 parts by mass based on 100 parts by mass of the copolymer, and cured sheets were obtained by treating them in a press under a load of 10 MPa at 120°C for 30 minutes, 150°C for 30 minutes, and then 250°C for 120 minutes.

[0122] Comparative Example 2: Preparation of Cured Sheet CP-2, an ethylene-styrene-divinylbenzene copolymer synthesized according to the manufacturing method described in WO 2022 / 014599, was used as a comparative example that did not contain cyclic olefin monomer units and was used for testing. This CP-2 had an ethylene content of 48.6% by mass, a styrene content of 44.7% by mass, a divinylbenzene content of 2.3% by mass, a number average molecular weight of 7189, and the number of divinylbenzene vinyl groups per number average molecular weight was 3.7. An uncured sheet (thickness 0.2 mm) was prepared, and the storage modulus at 25°C was measured, finding it to be less than 10 MPa. A cured sheet was obtained using CP-2 in the same manner as in Example 16, and physical properties were similarly determined.

[0123] Table 2 shows the formulations (units in the table are parts by mass) and physical properties (gel content, storage modulus at 25°C and 280°C, dielectric constant, and dielectric dissipation factor). The cured sheets obtained in Examples 16 to 34 and Comparative Example 2 exhibited high gel content and were sufficiently cured. Furthermore, they exhibited the low dielectric constant and low dielectric dissipation factor required for high-frequency insulating materials. Examples 16 to 34 exhibited superior dielectric properties to Comparative Example 2.

[0124]

[0125] Examples 18 and 21: Frequency Dependence of Dielectric Measurements For the cured sheets obtained in Examples 18 and 21, the dielectric constant and dielectric dissipation factor were measured at 10 GHz and 23° C. using a cavity resonator perturbation method (split cylinder resonator method), and the dielectric constant and dielectric dissipation factor were measured at 77 GHz and 23° C. using an open resonator method (Fabry-Perot resonator method). Furthermore, the ratio of the dielectric dissipation factor at 77 GHz to the dielectric dissipation factor at 10 GHz, Df (77 GHz / 10 GHz), was determined.

[0126] Examples 28 and 32 The dielectric constant and dielectric loss tangent at 10 GHz and 23° C. of the cured sheets obtained in Examples 28 and 32 were measured in the same manner.

[0127] Comparative Example 3: Frequency Dependence of Dielectric Measurement A COP (cyclic olefin polymer) test sample attached to a split cylinder resonator manufactured by Keysight Technologies, Inc., was used as a comparative example, designated CP-2, and the dielectric constant and dielectric loss tangent were measured in an uncured state at 10 GHz, 23°C, and 77 GHz, 23°C in the same manner as described above, to determine Df (77 GHz / 10 GHz). COP (cyclic olefin polymer) is a thermoplastic resin obtained by ring-opening metathesis polymerization of various cyclic olefin monomers and hydrogenation of double bond sites, and is generally known to have excellent low dielectric properties, but has a different composition from the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer according to the present invention.

[0128] Table 3 shows the formulations (units in the table are parts by mass) and the values ​​obtained by dielectric measurement (dielectric constant and dielectric loss tangent at 23°C and each frequency, Df (77 GHz / 10 GHz)). In Examples 18 and 21, Df (77 GHz / 10 GHz) was smaller than that in Comparative Example 3. This result indicates that the signal frequency dependency of the dielectric loss tangent is small and that the materials are excellent as high-frequency insulating materials.

[0129]

[0130] Example 35: Preparation of Cured Sheet Using a vial and a magnetic stirrer, 50 parts by weight of P-3 (ethylene-styrene-divinylbenzene-norbornene copolymer), 50 parts by weight of SA9000, and 100 parts by weight of toluene solvent were added and stirred to dissolve the copolymer and resin, producing a 50% by weight toluene solution (varnish). Furthermore, 0.75 parts by weight of curing agent VR-110 was added (externally divided by the weight of the copolymer), dissolved, and mixed by stirring to obtain a varnish-like composition (Table 4). A mold (frame length 7 cm, width 7 cm, thickness 1 mm) made from a silicone rubber sheet was placed on a smooth Teflon (registered trademark) sheet, and the varnish was poured into it and dried in a vacuum dryer at 80°C for at least 10 hours. The silicone rubber mold was then removed and a SUS mold (frame length 11 cm, width 11 cm, thickness 0.2 mm) was installed, and the mixture was pressed under a load of 10 MPa at 120°C for 30 minutes, 150°C for 30 minutes, and then 200°C for 120 minutes. The Teflon sheet and SUS mold were then removed to obtain a cured sheet. The gel fraction, storage modulus (25°C and 280°C), dielectric constant, and dielectric dissipation factor (all measured at 23°C and 40 GHz) of the resulting cured sheet were determined (Table 4).

[0131] Examples 36 to 41: Preparation of cured sheets Cured sheets were obtained in the same manner as in Example 35 using the compositions shown in Table 4, and their physical properties were determined in the same manner. However, in Example 41, Perbutyl P was used as the curing agent, and 0.05 parts by mass was added externally relative to the parts by mass of the copolymer.

[0132] Example 42: Preparation of Cured Sheet Using a vial and a magnetic stirrer, 50 parts by weight of P-3 (ethylene-styrene-divinylbenzene-norbornene copolymer), 50 parts by weight of HC-G0024 (63% by weight toluene solution) as a pure content, and 100 parts by weight of toluene solvent were added and stirred to dissolve the copolymer and resin, producing a 50% by weight toluene solution (varnish). Furthermore, 0.75 parts by weight of curing agent VR-110 was added (externally divided by the weight of the copolymer), dissolved, and mixed with stirring to obtain a varnish-like composition. A mold (frame length 7 cm, width 7 cm, thickness 1 mm) made from a silicone rubber sheet was placed on a smooth Teflon (registered trademark) sheet, and the varnish was poured into it and dried at 80°C in a vacuum dryer for at least 10 hours. The silicone rubber mold was then removed and a SUS mold (frame length 11 cm, width 11 cm, thickness 0.2 mm) was installed, and the mixture was pressed under a load of 10 MPa at 120°C for 30 minutes, 150°C for 30 minutes, and then 200°C for 120 minutes. The Teflon sheet and SUS mold were then removed to obtain a cured sheet. The gel fraction, storage modulus (25°C and 280°C), dielectric constant, and dielectric dissipation factor (all measured at 23°C and 40 GHz) of the resulting cured sheet were determined (Table 4).

[0133] Examples 43 to 49: Preparation of cured sheets Cured sheets were obtained and their physical properties were determined in the same manner as in Example 42. However, in Examples 47 to 49, Perbutyl P was used as the curing agent, and 0.05 parts by mass was added externally relative to the parts by mass of the copolymer.

[0134] Example 50: Preparation of Cured Sheet Using a vial and a magnetic stirrer, 30 parts by weight of P-11 (ethylene-styrene-divinylbenzene-norbornene copolymer), 70 parts by weight of HC-G0024 (63% by weight toluene solution) as a pure content, and 100 parts by weight of toluene solvent were added and stirred to dissolve the copolymer and resin, producing a 50% by weight toluene solution (varnish). Furthermore, 0.05 parts by weight of the curing agent Perbutyl P was added externally relative to the parts by weight of the copolymer, dissolved, and mixed with stirring to obtain a varnish-like composition. A mold (frame length 7 cm, width 7 cm, thickness 1 mm) made from a silicone rubber sheet was placed on a smooth Teflon (registered trademark) sheet, and the varnish was poured into it and dried at 80 ° C. in a vacuum dryer for 10 hours or more. The silicone rubber mold was then removed and a SUS mold (frame length 11 cm, width 11 cm, thickness 0.2 mm) was installed, and the mixture was pressed under a load of 10 MPa at 120°C for 30 minutes, 150°C for 30 minutes, and then 200°C for 120 minutes. The Teflon sheet and SUS mold were then removed to obtain a cured sheet. The gel fraction, storage modulus (25°C and 280°C), dielectric constant, and dielectric dissipation factor (all measured at 23°C and 40 GHz) of the resulting cured sheet were determined (Table 4).

[0135] Example 51: Preparation of cured sheet A cured sheet was obtained in the same manner as in Example 50 using the composition shown in Table 4, and the physical properties were determined in the same manner.

[0136] Table 4 shows the formulations (units in the table are parts by mass) and physical properties (gel content, storage modulus at 25°C and 280°C, dielectric constant, and dielectric dissipation factor). The cured sheets obtained in Examples 35 to 51 exhibited a high gel content and were sufficiently cured. The storage modulus at room temperature (25°C) was sufficient for use as a substrate, particularly a rigid substrate. Furthermore, they exhibited the low dielectric constant and low dielectric dissipation factor required for high-frequency insulating materials.

[0137]

Claims

1. An α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, in which the copolymer in an uncured state has a dielectric constant of less than 2.5 at a measurement frequency of 40 GHz, a dielectric dissipation factor of less than 0.0007, and a storage modulus measured at 25°C of less than 1000 MPa.

2. The copolymer according to claim 1, wherein the total content of metals derived from the catalyst and co-catalyst contained in said copolymer is 1500 ppm or less.

3. The copolymer according to claim 1 or 2, which when cured alone has a dielectric constant of less than 2.5 at a measurement frequency of 40 GHz, a dielectric dissipation factor of less than 0.0006, and a storage modulus measured at 25°C of less than 1000 MPa.

4. The copolymer according to any one of claims 1 to 3, which, when cured alone, has a storage modulus of 1 MPa or more as measured at 280°C.

5. The copolymer according to any one of claims 1 to 4, satisfying all of the following (1) to (6): (1) The number average molecular weight of the copolymer is 500 or more and 30,000 or less. (2) The α-olefin monomer units are α-olefin monomer units having 2 to 20 carbon atoms. (3) The aromatic vinyl compound monomer units are monomer units derived from an aromatic vinyl compound having 8 to 20 carbon atoms and one vinyl group or vinylene group in the molecule. (4) The cyclic olefin monomer units are cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 10% by mass or more and less than 50% by mass. (5) The aromatic polyene monomer is one or more selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and / or vinylene groups in the molecule, the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units contained in the copolymer is 2 or more per number average molecular weight, and the number average molecular weight per vinyl group and / or vinylene group derived from the aromatic polyene monomer units is 250 to 10,000. (6) The total of the α-olefin monomer units, cyclic olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass.

6. The copolymer according to any one of claims 1 to 5, wherein the cyclic olefin monomer units comprise monomer units derived from one or more members selected from the group consisting of norbornene, methylphenylnorbornene, substituted norbornenes other than methylphenylnorbornene, and dimethanooctahydronaphthalene.

7. The copolymer according to any one of claims 1 to 6, wherein the uncured copolymer has a glass transition temperature determined by DSC in the range of -30°C or higher and lower than 35°C.

8. A method for producing the copolymer according to any one of claims 1 to 7, wherein the monomers of an α-olefin, a cyclic olefin, an aromatic vinyl compound, and an aromatic polyene are copolymerized by coordination polymerization using a coordination polymerization catalyst.

9. The method for producing a copolymer according to claim 8, wherein the coordination polymerization catalyst is a polymerization catalyst comprising a transition metal compound represented by the following general formula (1) and a co-catalyst: In the formula, A and B are each independently a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzoindenyl group, an unsubstituted or substituted cyclopentadienyl group, or an unsubstituted or substituted indenyl group. Y is bonded to A and B and is a methylene group, silylene group, ethylene group, germylene group, or boron residue having hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as a substituent. The substituents may be different or the same. Y may also have a cyclic structure. X is hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylaryl group having 8 to 12 carbon atoms, a silyl group having a hydrocarbon substituent having 1 to 4 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having an alkyl substituent having 1 to 6 carbon atoms. M is zirconium, hafnium, or titanium.

10. The method for producing a copolymer according to claim 9, wherein A and B in general formula (1) are each independently a group selected from the group consisting of an unsubstituted or substituted cyclopentadienyl group and an unsubstituted or substituted indenyl group.

11. The method according to claim 9 or 10, wherein a cocatalyst containing a boron compound is used.

12. The process of claim 11, wherein the cocatalyst further comprises an aluminum compound.

13. A cured product comprising the copolymer according to any one of claims 1 to 7.

14. A cured product of a composition comprising the copolymer according to any one of claims 1 to 7 and one or more additive components selected from the group consisting of resin components, curing agents, monomers, solvents, and fillers, wherein the cured product exhibits a dielectric constant of 3.5 or less and a dielectric dissipation factor of 0.0015 or less at a measurement frequency of 40 GHz.

15. A cured body for high-frequency insulation substantially composed of a hydrocarbon-based material, in which the value of Df (77 GHz / 10 GHz), which is the ratio of the dielectric loss tangent measured at 23°C and 77 GHz using the open resonator method (Fabry-Perot resonator method) to the dielectric loss tangent measured at 23°C and 10 GHz using the cavity resonator perturbation method (split cylinder resonator method), is 1.3 or less.

16. The cured product according to claim 15, wherein the hydrocarbon-based material is a cured product comprising an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, the uncured copolymer having a dielectric constant of less than 2.5 at a measurement frequency of 40 GHz, a dielectric dissipation factor of less than 0.0007, and a storage modulus measured at 25°C of less than 1000 MPa.

17. A resin composition comprising the copolymer according to any one of claims 1 to 7 and an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following (a) to (f): (a) the number average molecular weight of the copolymer is 500 or more and 100,000 or less; (b) the α-olefin monomer units are α-olefin monomer units having 2 to 20 carbon atoms; (c) the aromatic vinyl compound monomer units are monomer units derived from an aromatic vinyl compound having 8 to 20 carbon atoms and one vinyl group or vinylene group in the molecule; (d) the cyclic olefin monomer units are cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 50% by mass or more and 99% by mass or less. (e) the aromatic polyene monomer units are monomer units derived from one or more polyenes selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units per number average molecular weight is 2 to 30. (f) The total of the α-olefin monomer units, cyclic olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass.

18. A resin composition comprising the copolymer according to any one of claims 1 to 7 and an olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following (A) to (E): (A) the number-average molecular weight of the copolymer is 500 or more and 100,000 or less; (B) the olefin monomer unit is a single or multiple units selected from α-olefin monomer units having 2 to 20 carbon atoms, and the olefin monomer units do not contain cyclic olefin monomer units; (C) the aromatic vinyl compound monomer unit is a monomer unit derived from an aromatic vinyl compound having 8 to 20 carbon atoms and one vinyl or vinylene group in the molecule, and the content of the aromatic vinyl compound monomer unit is 0% by mass or more and 90% by mass or less. (D) The aromatic polyene monomer units are monomer units derived from one or more polyenes selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and / or vinylene groups in the molecule, and the content of the vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units is 2 to 30 per number average molecular weight, and the content of the vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units is 2 to less than 30 per number average molecular weight. (E) The total of the olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass.

19. A cured product of the resin composition according to claim 17 or 18.

20. The cured product according to claim 13, 14, 15, 16, or 19, which is an electrical insulating material.

21. A CCL substrate, FCCL substrate, interlayer insulating material, resin coated copper (RCC), coverlay, high frequency transmission circuit, or antenna, comprising the cured product according to claim 20.

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