Copolymer, method for producing the same, and cured body containing the copolymer

Abstract

To provide a novel copolymer that exhibits excellent low dielectric properties and high elastic modulus at room temperature in its uncured state. [Solution] An α-olefin-cyclic olefin-aromatic polyene copolymer in an uncured state, having a dielectric constant of less than 2.4 and a dielectric loss tangent of less than 0.0008 at a measurement frequency of 40 GHz, and a storage modulus of 1000 MPa or more measured at 25°C.

Description

[Technical Field]

[0001] The present invention relates to copolymers, methods for producing the same, and cured products containing the copolymer. [Background technology]

[0002] As communication frequencies shift to the gigahertz band and higher frequencies, there is a growing need for multilayer substrates made of CCL or FCCL containing insulating materials with low dielectric properties. Fluorine-based resins such as perfluoroethylene have excellent low dielectric constant, low dielectric loss, and heat resistance, but they have difficulties in moldability and film formation, and there are also issues with adhesion to copper foil wiring, making them difficult to apply to multilayer substrates. On the other hand, substrates and insulating materials using post-curing resins such as epoxy resins, unsaturated polyester resins, polyimide resins, and phenolic resins have been widely used due to their heat resistance and ease of handling, but their dielectric constant and dielectric loss are relatively high, and improvement is desired for high-frequency insulating materials (Patent Document 1).

[0003] Therefore, attention is being drawn to hydrocarbon resins that inherently possess low dielectric properties. In particular, cyclic olefin-based (co)polymers with high glass transition temperatures (Tg) have been proposed as insulating materials in the form of thermoplastic resins (Patent Documents 2 and 3). However, since their glass transition temperature is close to the solder reflow temperature, crosslinkable (curable) resins are preferable when considering process compatibility and process window. In order to make hydrocarbon resins, which are inherently thermoplastic resins, into curable resins, it is necessary to introduce crosslinkable functional groups, but generally, radical or heat-reactive functional groups have polarity, which worsens the low dielectric properties. When attempting to introduce functional groups composed solely of hydrocarbons, such as aromatic vinyl groups, it is often necessary to utilize intermolecular reactions between expensive hydrocarbon raw materials (Patent Document 4), which is often not economical. Patent Document 5 shows a cured product consisting of an ethylene-olefin (aromatic vinyl compound)-aromatic polyene copolymer and a non-polar vinyl compound copolymer obtained from a specific coordination polymerization catalyst and having a specific composition and formulation. In this technology, only one of the two vinyl groups of an aromatic polyene (divinylbenzene) is selectively copolymerized, and the remaining vinyl group is preserved, making it easy to obtain a crosslinkable hydrocarbon copolymer macromonomer having the functional group of an aromatic vinyl group. Cured bodies obtained from similar compositions of olefin-aromatic vinyl compound-aromatic polyene copolymers and auxiliary raw materials have the characteristics of low dielectric constant and low dielectric loss tangent, and by selecting the composition and appropriate auxiliary raw materials, it is possible to give a wide range of physical properties from soft to hard (Patent Documents 6 and 7). However, the olefin-aromatic vinyl compound-aromatic polyene copolymers specifically described are relatively soft, and in order to harden them, it is necessary to blend in a large amount of other crosslinkable hard resins or inorganic fillers. Here, known crosslinkable hard resins do not have sufficient low dielectric properties, and blending in large amounts reduces the low dielectric properties of the cured body. When inorganic fillers are blended in a relatively large amount, the dielectric constant of the resulting cured body becomes particularly high because inorganic fillers generally have a high dielectric constant.In cured materials, it is important that they are hard and simultaneously exhibit a high glass transition temperature (Tg). This allows them to exhibit a low coefficient of thermal expansion (CTE) within the processing temperature range of the manufacturing process of electronic circuit components, including the solder reflow process. Therefore, there is a demand for hard resins with higher glass transition temperatures. Furthermore, insulating materials used in substrates and the like are made by mixing and curing various resins, fillers, flame retardants, and other raw materials, and high compatibility with these raw materials is also required. In particular, resins and flame retardants contain many aromatic groups to achieve stability and flame retardancy at high temperatures, so there is a demand for crosslinkable hard materials with high compatibility with these. From the above, there is a demand for materials that are crosslinkable, whose cured products have excellent low dielectric properties, a high glass transition temperature, and a high modulus of elasticity at room temperature and high temperatures. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-192392 [Patent Document 2] International Publication No. 1998 / 56011 [Patent Document 3] Japanese Patent Publication No. 2016-037045 [Patent Document 4] Japanese Patent Publication No. 2004-087639 [Patent Document 5] Japanese Patent Publication No. 2007-217706 [Patent Document 6] International Publication No. 2021 / 112087 [Patent Document 7] International Publication No. 2021 / 112088 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, the aforementioned prior art does not describe how α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymers possess sufficient levels of low dielectric properties, high glass transition temperature, and high elastic modulus in their uncured state. [Means for solving the problem]

[0006] In view of the above-mentioned problems, the present invention aims to provide a novel crosslinkable copolymer (polymer compound) and a cured product thereof, in which the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer exhibits low dielectric properties even in an uncured state, has a high glass transition temperature, and has a high elastic modulus at room temperature and high temperatures.

[0007] In other words, the present invention can provide the following embodiments.

[0008] Appearance 1. An α-olefin-cyclic olefin-aromatic polyene copolymer in its uncured state, having a dielectric constant of less than 2.4 and a dielectric loss tangent of less than 0.0008 at a measurement frequency of 40 GHz, and a storage modulus of 1000 MPa or more measured at 25°C. Appearance 2. An α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer in its uncured state, having a dielectric constant of less than 2.4 and a dielectric loss tangent of less than 0.0008 at a measurement frequency of 40 GHz, and a storage modulus of 1000 MPa or more measured at 25°C.

[0009] Appearance 3. The copolymer according to embodiment 1 or 2, wherein the uncured copolymer has a dielectric constant of less than 2.3 and a dielectric loss tangent of less than 0.0004 at a measurement frequency of 40 GHz.

[0010] Appearance 4. The copolymer according to any one of embodiments 1 to 3, wherein the total metal content derived from the catalyst and co-catalyst contained in the copolymer is 1000 ppm or less.

[0011] Appearance 5. When cured alone, the copolymer according to any one of Aspects 1 to 4, wherein the cured product has a dielectric constant of less than 3.5 and a dielectric loss tangent of less than 0.001 at a measurement frequency of 40 GHz.

[0012] Aspect 6. When cured alone, the copolymer according to any one of Aspects 1 to 5, wherein the cured product has a dielectric constant of less than 2.3 and a dielectric loss tangent of less than 0.0004 at a measurement frequency of 40 GHz.

[0013] Aspect 7. When cured alone, the copolymer according to any one of Aspects 1 to 6, wherein the storage modulus of the cured product measured at 280 °C is 1 MPa or more.

[0014] Aspect 8. When cured alone, the copolymer according to any one of Aspects 1 to 7, wherein the storage modulus of the cured product measured at 280 °C is 5 MPa or more.

[0015] Aspect 9. The copolymer according to any one of Aspects 1 to 8, which satisfies all of the following (1) to (2), (4) to (6). (1) The number average molecular weight of the copolymer is 500 or more and 100,000 or less. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 to 30 carbon atoms, and its content is 30% by mass or more and 99% by mass or less. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms 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 unit is 2 or more and 30 or less per number average molecular weight. (6) The total of the α-olefin unit, the cyclic olefin unit, and the aromatic polyene unit is 100% by mass.

[0016] Aspect 10. The copolymer according to Aspect 2, which satisfies all of the following (1) to (6). (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 or more carbon atoms and 20 or fewer carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 to 30 carbon atoms, and its content is 30% to 99% by mass. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl and / or vinylene groups in the molecule, and the content of vinyl and / or vinylene groups derived from the aromatic polyene monomer unit is 2 to 30 per number average molecular weight. (6) The total of α-olefin units, cyclic olefin units, aromatic vinyl compound units, and aromatic polyene units is 100% by mass.

[0017] Appearance 11. The copolymer according to any one of embodiments 1 to 10, wherein the cyclic olefin unit comprises one or more selected from the group consisting of norbornene, methylphenylnorbornene, substituted norbornene other than methylphenylnorbornene, and dimethanooctahydronaphthalene.

[0018] Appearance 12. A copolymer according to any one of embodiments 1 to 11, wherein the glass transition temperature is in the range of 100°C to 350°C.

[0019] Appearance 13. A copolymer according to any one of embodiments 1 to 12, wherein the number average molecular weight is 500 or more and less than 30,000.

[0020] Appearance 14. A method for producing a copolymer according to any one of embodiments 1 to 13, wherein monomers of an α-olefin, a cyclic olefin, and an aromatic polyene, and optionally an aromatic vinyl compound, are copolymerized by coordination polymerization using a coordination polymerization catalyst.

[0021] Appearance 15. The method for producing a copolymer according to embodiment 14, 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. General formula (1) [ka] In the formula, A and B are each independently 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 from each other or the same. Also, Y may have a cyclic structure. X is hydrogen, a 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 1 to 4 carbon atoms with a hydrocarbon substituent, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having 1 to 6 carbon atoms with an alkyl substituent. M stands for zirconium, hafnium, or titanium.

[0022] Appearance 16. A method for producing a copolymer according to embodiment 15, wherein A and B in general formula (1) are each independently selected from unsubstituted or substituted cyclopentadienyl groups or unsubstituted or substituted indenyl groups.

[0023] Appearance 17. A manufacturing method according to embodiment 15 or 16, wherein a co-catalyst containing a boron compound is used.

[0024] Appearance 18. The manufacturing method according to embodiment 17, wherein the co-catalyst further comprises an aluminum compound.

[0025] Appearance 19. A cured body comprising the copolymer described in any of embodiments 1 to 13.

[0026] Appearance 20. An α-olefin-cyclic olefin-aromatic polyene copolymer that satisfies all of the following conditions (1) to (2) and (4) to (6), (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 to 30 carbon atoms, and its content is 30% to 99% by mass. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl and / or vinylene groups in the molecule, and the content of vinyl and / or vinylene groups derived from the aromatic polyene monomer unit is 2 to 30 per number average molecular weight. (6) The total of α-olefin units, cyclic olefin units, and aromatic polyene units is 100% by mass. One or more additive components selected from the group consisting of resin components, curing agents, monomers, solvents, and fillers. A cured body of a composition containing, A cured body exhibiting 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.

[0027] Appearance 21. An α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer that satisfies all of the following (1) to (6), (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 or more carbon atoms and 20 or fewer carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 to 30 carbon atoms, and its content is 30% to 99% by mass. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl and / or vinylene groups in the molecule, and the content of vinyl and / or vinylene groups derived from the aromatic polyene monomer unit is 2 to 30 per number average molecular weight. (6) The total of α-olefin units, cyclic olefin units, aromatic vinyl compound units, and aromatic polyene units is 100% by mass. One or more additive components selected from the group consisting of resin components, curing agents, monomers, solvents, and fillers. A cured body of a composition containing, A cured body exhibiting 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.

[0028] Appearance 22. Furthermore, the cured body according to any one of embodiments 19 to 21, wherein the storage modulus measured at 25°C is 1000 MPa or more, and the storage modulus measured at 280°C is 1 MPa or more.

[0029] Appearance 23. A cured body according to any one of embodiments 19 to 22, which is an electrical insulating material.

[0030] Appearance 24. A CCL substrate, an FCCL substrate, an interlayer insulating material, a coverlay, a high-frequency transmission circuit, or an antenna, comprising the cured body described in Embodiment 23.

[0031] Appearance 25. A method for producing a cured product, comprising the step of polymerizing a copolymer according to at least one of embodiments 1 to 13 with a radical polymerization initiator composed only of carbon atoms and hydrogen atoms, and not containing oxygen atoms or nitrogen atoms in its structure. [Effects of the Invention]

[0032] The copolymer according to the present invention exhibits excellent low dielectric properties even in its uncured state, has a high modulus of elasticity at room temperature, and is curable. Furthermore, the cured product of the copolymer also exhibits excellent low dielectric properties, a high glass transition temperature, and a high modulus of elasticity at both room temperature and high temperatures. If the copolymer satisfies the above-mentioned properties in its uncured state, the cured product containing this copolymer can also satisfy these properties. [Modes for carrying out the invention]

[0033] Further details are provided below. In this specification, α-olefin-cyclic olefin-aromatic polyene copolymers are sometimes included in α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymers, and the latter name may be used collectively. In this specification, α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymers may be simply referred to as the copolymer of the present invention, or simply as copolymers. Numerical ranges in this specification include upper and lower limits unless otherwise specified. In this specification, the term "sheet" also includes the concept of "film." Furthermore, even if the term "film" is used in this specification, it has the same meaning as "sheet." Furthermore, even if the term "film" is used in this specification, it also includes the concept of "sheet." In this specification, the uncured state is defined as a state in which the gel content of the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer is 20% by mass or less, more precisely 10% by mass or less, and most precisely 5% by mass or less. The gel content is a value obtained by measurement in accordance with JIS K6796:1998, or by measurement in accordance with ASTM D2765-84, which corresponds to ISO 10147:1994, the equivalent of JIS.

[0034] In one embodiment of the present invention, an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer can be provided. In its uncured state, the copolymer may exhibit a dielectric constant of less than 2.4, preferably less than 2.3, 2.0 or more, and a dielectric loss tangent of less than 0.0008, preferably less than 0.0004, more preferably less than 0.0003, 0.0001 or more, at a measurement frequency of 40 GHz. Furthermore, the storage modulus measured at 25°C is 1000 MPa or more. When the copolymer is cured alone, the cured product may exhibit a dielectric constant of less than 3.5, a dielectric loss tangent of less than 0.0010, preferably a dielectric constant of 2.0 or more and less than 3.5, and a dielectric loss tangent of 0.0001 or more and less than 0.0010, more preferably a dielectric constant of less than 2.4, 2.0 or more, and a dielectric loss tangent of less than 0.0004, most preferably a dielectric constant of less than 2.3 and a dielectric loss tangent of less than 0.0003, 0.0001 or more, at a measurement frequency of 40 GHz. Furthermore, the storage modulus measured at 25°C may be 1000 MPa or more. Preferably, the storage modulus measured at 280°C of the cured body is 1 MPa or more, and more preferably 5 MPa or more.

[0035] In another embodiment, 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 do satisfy the above conditions.

[0036] <α-olefin-cyclic olefin-aromatic polyene copolymer> Furthermore, the α-olefin-cyclic olefin-aromatic polyene copolymer of the present invention is a copolymer having monomer units of α-olefin, cyclic olefin, and aromatic polyene, and the method of producing it is arbitrary. Preferably, the α-olefin-cyclic olefin-aromatic polyene copolymer is a copolymer that satisfies all of the following (1) to (2) and (4) to (6). (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer having 10 to 30 carbon atoms, which may have an aromatic ring, and its content is 30% by mass or more and 99% by mass or less. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having 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 or 2 to less than 30 per number average molecular weight. (6) The total amount of monomer units of α-olefins, cyclic olefins, and aromatic polyenes is 100% by mass.

[0037] This α-olefin-cyclic olefin-aromatic polyene copolymer is obtained by copolymerizing the monomers of α-olefin, cyclic olefin, and aromatic polyene.

[0038] <α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer> In one embodiment of the present invention, it is preferable to use an aromatic vinyl compound to obtain an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer. In this specification, α-olefin-cyclic olefin-aromatic polyene copolymers are sometimes included within α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymers, and the latter name may be used collectively. Furthermore, the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer of the present invention is a copolymer having monomer units of α-olefin, cyclic olefin, aromatic vinyl compound, and aromatic polyene, and the method of producing it is arbitrary. Preferably, the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer is a copolymer that satisfies all of the following (1) to (6). (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 or more carbon atoms and 20 or fewer carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer having 10 to 30 carbon atoms, which may have an aromatic ring, and its content is 30% by mass or more and 99% by mass or less. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having 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 or 2 to less than 30 per number average molecular weight. (6) The total amount of monomer units of α-olefins, cyclic olefins, aromatic vinyl compounds, and aromatic polyenes is 100% by mass.

[0039] This α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer is obtained by copolymerizing the monomers of α-olefin, cyclic olefin, aromatic vinyl compound, and aromatic polyene.

[0040] The α-olefin monomer is an α-olefin having 2 to 20 carbon atoms, and examples include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene, with ethylene being the most preferred. In this copolymer, the α-olefin content is arbitrary, but preferably 0% to 40% by mass, more preferably more than 0% by mass and 30% by mass or less, even more preferably 1% to 30% by mass or less, and most preferably 5% to 30% by mass or less. When the α-olefin monomer unit content is 40% by mass or less, the content of cyclic olefin units is relatively high, and the glass transition temperature of the copolymer can be kept within a preferred range. The higher the α-olefin monomer unit content (for example, 5% by mass or more), the less brittle the copolymer and its cured product become.

[0041] In this specification, a cyclic olefin monomer refers to a cyclic olefin having 7 to 30 carbon atoms (preferably 10 to 30 carbon atoms). A cyclic olefin having 7 to 30 carbon atoms is a cyclic olefin having one or more alicyclic structures in its molecule and polymerizable vinyl groups, vinylene groups, or vinylidene groups. Preferred cyclic olefins are those having a hydrocarbon ring structure without heteroatoms, and more preferably cyclic olefins having an unsaturated hydrocarbon ring. Such cyclic olefins have the remarkable characteristics of low dielectric properties and high glass transition temperatures, while being easier to prepare with inexpensive raw materials and simple processes compared to conventional engineering plastics. Examples of such cyclic olefins include norbornenes. Norbornenes are monomers selected from norbornene and substituted norbornenes. Norbornene can be synthesized, for example, by the Diels-Alder reaction of ethylene and cyclopentadiene. Furthermore, substituted norbornene refers to substituted norbornene having polymerizable vinyl, vinylene, or vinylidene groups within the molecule, with examples including dimethanooctahydronaphthalene (DMON) and trimetanododecahydroanthracene (TMDA). These are also Diels-Alder reaction products of norbornene compounds 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 cyclic olefins having a larger number of ring structures and a higher molecular weight, such as dimethanooctahydronaphthalene (DMON) and trimetanododecahydroanthracene (TMDA). By copolymerizing such cyclic olefins, copolymers with a higher glass transition temperature (Tg) can be obtained with a smaller molar content of monomer units. Therefore, it is possible to increase the molar content of other monomer units while maintaining the high glass transition temperature of the copolymer. Increasing the molar content of aromatic vinyl compound monomer units as other monomer units enhances the aromatic properties of the copolymer as a whole, which is preferable as it improves compatibility with other raw materials and resins of the copolymer.These high molecular weight cyclic olefins may be used alone or copolymerized as mixtures with norbornene, etc. In particular, DMON and TMDA may be obtained as mixtures with norbornene when produced by Diels-Alder Reaction, and it is possible to reduce production costs by using the mixture as is in polymerization. Furthermore, in the present invention, more preferred cyclic olefins are norbornene having aromatic substituents, and examples include phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), a Diels-Alder Reaction product of cyclopentadiene and styrene; indanylnorbornene (1,4-methano-1,9a,4,4a-tetrahydrofluorene), a Diels-Alder Reaction product of cyclopentadiene and indene; and methylphenylnorbornene (MPNB, 5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene), a Diels-Alder Reaction product of cyclopentadiene and α-methylstyrene. Norbornene having such aromatic substituents can impart a higher glass transition temperature (Tg) to the copolymer when copolymerized, and further exhibit aromaticity, thus demonstrating 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 preferable because it can improve the heat oxidation resistance of the resulting copolymer, as described in Japanese Patent Publication No. 2005-239975. These norbornene having aromatic substituents are specifically described in, for example, Japanese Patent Publication No. 11-504669 and Japanese Patent Publication No. 2005-239975. The optimal content of cyclic olefin units contained in this copolymer varies depending on the type of cyclic olefin, but is, for example, 50% by mass or more and 99% by mass or less, preferably 50% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 95% by mass or less, and most preferably 80% by mass or more and 95% by mass or less. The optimal content of cyclic olefin units in this copolymer may be less than 90% by mass, from the viewpoint of imparting a certain degree of toughness to the copolymer. Having a content within this range makes it easier to achieve the desirable high glass transition temperature of the copolymer.The preferred glass transition temperature of the copolymer is 100°C to 350°C, more preferably 130°C to 300°C, and most preferably 180°C to 300°C. Those skilled in the art can appropriately adjust the type and content of the cyclic olefin used to achieve this preferred glass transition temperature.

[0042] In preferred embodiments, the cyclic olefin units contained in the copolymer may include one or more selected from the group consisting of norbornene, methylphenylnorbornene, substituted norbornene other than methylphenylnorbornene, and dimethanooctahydronaphthalene, and more preferably, one or more selected from the group consisting of norbornene, methylphenylnorbornene, and dimethanooctahydronaphthalene.

[0043] The aromatic vinyl compound monomer is an aromatic vinyl compound having 8 to 20 carbon atoms, and examples include styrene, paramethylstyrene, ethyl vinylbenzene, para-isobutylstyrene, various vinylnaphthalenes, and various vinylanthracenes. This aromatic vinyl compound may also be included in the copolymer as a result of copolymerization of components contained as impurities in the aromatic polyene used in polymerization. The content of aromatic vinyl compound monomer units in this copolymer is arbitrary, but preferably 0% by mass or more and 40% by mass or less, more preferably 0% by mass or more and 30% by mass or less, even more preferably 0% by mass or more and 20% by mass or less, still more preferably 0% by mass or more and 10% by mass or less, and still more preferably 0% by mass. The content of aromatic vinyl compound monomer units in this copolymer may exceed 0% by mass. The content of aromatic vinyl compound monomer units in this copolymer may be 30% by mass or less, less than 30% by mass, 10% by mass or less, less than 10%, 1% by mass or less, less than 1% by mass, and less than 0.5% by mass.

[0044] When the content of aromatic vinyl compound monomer units is 40% by mass or less, the content of cyclic olefin units becomes relatively high, making it possible to raise the glass transition temperature of the copolymer. On the other hand, when the content of aromatic vinyl compound monomer units is 10% by mass or more, preferably 30% by mass or more, it is possible to improve the aromaticity of the copolymer, especially when the cyclic olefin of the copolymer of the present invention does not have aromatic substituents. This improves compatibility with other resin materials, flame retardants, and fillers, suppresses bleed-out of flame retardants, and facilitates high-fillerization, which is preferable. As described above, the glass transition temperature and aromaticity of the copolymer can be adjusted by the aromatic vinyl compound content of the copolymer.

[0045] The aromatic polyene monomer is a polyene having 5 to 20 carbon atoms and having 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 having multiple vinyl groups in its molecule, and more preferably a compound having an aromatic vinyl structure such as ortho, meta, or para divinylbenzene or mixtures thereof, divinylnaphthalene, divinylanthracene, p-2-propenylstyrene, or p-3-butenylstyrene, which is substantially free of oxygen, nitrogen, and halogens and composed of carbon and hydrogen. Alternatively, a bifunctional aromatic vinyl compound described in Japanese Patent Application Publication No. 2004-087639, such as 1,2-bis(vinylphenyl)ethane (abbreviated as BVPE), can also be used. Among these, ortho, meta, or para divinylbenzene or mixtures thereof are preferably used, and most preferably a mixture of meta and para-divinylbenzene is 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 the curing process, making curing easier.

[0046] The number-average molecular weight of this copolymer is preferably 500 to 100,000, more preferably 500 to 30,000 or 500 to less than 30,000, even more preferably 500 to 15,000 or 500 to less than 15,000, and still more preferably 500 to 12,000 or 500 to less than 12,000. When the number-average molecular weight is 500 or more, the mechanical properties of the composition in the uncured stage are enhanced, and the tackiness becomes appropriate, resulting in the effect of facilitating molding as a thermoplastic resin. When the number-average molecular weight is 30,000 or less, the moldability is improved. In particular, when the number-average molecular weight is 30,000 or less, or 12,000 or less, it is advantageous because it allows the viscosity of the varnish containing this copolymer to be kept below a certain value. When the viscosity of the varnish is lower than a certain value, the workability is improved, and it becomes easier to impregnate glass fibers and the like with the varnish, improving the embedding ability in semiconductor devices with uneven surfaces.

[0047] In this copolymer, the content of vinyl groups and / or vinylene groups derived from aromatic polyene units is 2 to 30 per number average molecular weight, preferably 3 to 20. The content of vinyl groups and / or vinylene groups derived from aromatic polyene units may be less than 30 per number average molecular weight, preferably less than 20. The content of vinyl groups and / or vinylene groups may collectively refer to as "vinyl group content" below. Since vinyl groups are superior to vinylene groups in terms of crosslinking efficiency, in the present invention, the content of vinyl groups derived from aromatic polyene units (in this case, not including vinylene groups) is preferably 2 to 30 per number average molecular weight, preferably 3 to 20. When the vinyl group content is 2 or more, the crosslinking efficiency is high and a cured product with sufficient crosslinking density can be obtained. As the vinyl group content increases, it becomes easier to improve the mechanical properties of the final cured product at room temperature and high temperature. The vinyl group content derived from aromatic polyene units (divinylbenzene units) per number-average molecular weight in the copolymer is determined by the number-average molecular weight (Mn) on a standard polystyrene basis, which is known to those skilled in the art by the GPC (gel permeation chromatography) method. 1H-NMR measurement and / or quantitative mode 13 This can be obtained by comparing the composition obtained by 13C-NMR measurement with the vinyl group content derived from aromatic polyene units. Such methods are obvious and well known to those skilled in the art. Alternatively, the method described in the prior art documents patents of this specification can also be used. The content of aromatic polyene monomer units in this copolymer is arbitrary, but preferably less than 40% by mass, more preferably less than 30% by mass. Such a content appropriately suppresses the number of crosslinking groups, resulting in improved stability during copolymer production and curing.

[0048] In this copolymer, as the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, specifically, one or more of the group consisting of 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 can be cited as examples of preferred materials. Copolymers in which norbornene is substituted with dimethanooctahydronaphthalene (DMON), trimetanododecahydroanthracene (TMDA), phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), or methylphenylnorbornene (5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene) are also examples of suitable copolymers of the present invention.

[0049] In an α-olefin-cyclic olefin-aromatic polyene copolymer or α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer according to a certain embodiment, an embodiment in which the content of α-olefin monomer units is 0% by mass (i.e., does not contain α-olefin monomer units) can also be provided. Such copolymers are also referred to in this specification as "cyclic olefin-aromatic polyene copolymer" or "cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer". A copolymer according to this embodiment will be described below. Here, the types of monomers of cyclic olefin, aromatic vinyl compound, and aromatic polyene, and the content of each monomer unit in the copolymer are as described above.

[0050] The above-described cyclic olefin-aromatic polyene copolymer or cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer can be produced by the production method described herein. Specifically, it can be produced from monomers of a cyclic olefin, an aromatic vinyl compound, and an aromatic polyene using a coordination polymerization catalyst consisting of a transition metal compound and a co-catalyst. The chemical structure of the copolymer obtained using the coordination polymerization catalyst consisting of a combination of a transition metal compound and a co-catalyst is characterized by the absence of a specific structure. That is, conventional copolymers obtained by the cationic polymerization method according to the prior art have characteristic polymer end structures, such as those described in International Publication No. 2018 / 181842, but the copolymer according to the embodiment of the present invention has the significant difference of not having such a structure. This difference provides the effect of facilitating molecular design in the present invention.

[0051] The polymer terminal structures contained in cyclic olefin-aromatic polyene copolymers or cyclic olefin-aromatic vinyl compound-aromatic polyene copolymers are 1 H-NMR, 13This can be qualitatively or quantitatively determined by known methods using 1C-NMR. As a typical example of such copolymers, the polymer terminal structures contained in a cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer composed of norbornene, DMON, MPNB as a cyclic olefin, styrene or ethyl vinylbenzene as an aromatic vinyl compound, and divinylbenzene as an aromatic polyene are substantially one of the structures represented by E-1 to E-8 below, or any combination thereof. These structural formulas can be understood by substituting the corresponding structures in the case of cyclic olefins other than those mentioned above, aromatic vinyl compounds other than those mentioned above, or aromatic polyenes other than divinylbenzene. "Substantially" means that 90 mol% or more, preferably 95 mol% or more, and most preferably 99 mol% or more of the total terminal structures of the copolymer are one of the structures represented by E-1 to E-8 below, or any combination thereof.

[0052] [ka]

[0053] In the above formula, P represents a polymer structure residue of norbornene (or DMNO, or MPNB)-styrene (or ethyl vinylbenzene)-divinylbenzene copolymer. Z represents hydrogen, an ethyl group, or a vinyl group.

[0054] Furthermore, when the cyclic olefin is DMON or MPNB, the structure including substituents R1 and R2 is as shown below.

[0055] [ka]

[0056] The polymerization initiation ends, which account for about half of the polymer end structures, are generally E-1, E-2, E-4, and E-5. These structures are saturated ends, and therefore, aromatic vinyl compound-aromatic polyene copolymers inherently possess high durability, such as heat resistance. The proportion of polymerization initiation end structures varies depending on various factors, such as whether the first monomer insertion occurs to a metal-hydrogen bond or to a metal-alkyl group structure, whether the first monomer insertion occurs with a cyclic olefin, styrene, or divinylbenzene, and whether it is a 2,1 insertion or a 1,2 insertion when the first monomer is styrene or divinylbenzene.

[0057] Furthermore, regarding the structure of the chain transfer end (also called the polymerization termination end) of the polymer growth chain within the polymer end structure, E-1, E-6, and E-8 are generally the most common, with E-3, E-4, and E-7 also present. The proportion of chain transfer end structures can vary depending on whether chain transfer occurs by hydrogen abstraction at the beta position, by chain transfer to other coordination monomers, by chain transfer to alkylaluminum co-catalyst components, or by chain transfer agents such as hydrogen. Generally, cyclic olefins have a rigid structure, so E-3 structures resulting from hydrogen abstraction at the beta position are less common.

[0058] The polymer terminal structures of the above-mentioned cyclic olefin-aromatic polyene copolymer or cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer consist of one or more of the structures E-1 to E-8 above, and substantially no other structures are included. The aromatic vinyl compound-aromatic polyene copolymer, which may contain an olefin according to the present invention, is obtained by a specific coordination polymerization, and is a copolymer with relatively few polymer chain branching degrees and high linearity, and the proportion of polymer terminal structures included is also relatively small.

[0059] This section describes an example of a polymer obtained by cationic polymerization according to the prior art and compares it with the present invention. The characteristic terminal structures (structures denoted as t1 and t2 in International Publication No. 2018 / 181842) formed by chain transfer such as electrophilic substitution reactions of carbon cations at the polymer growth ends to aromatic monomers or aromatic rings contained in the polymer itself, as described in International Publication No. 2018 / 181842, are not included in the copolymer according to the present invention. On the other hand, the aromatic vinyl compound-aromatic polyene copolymer according to the prior art described in International Publication No. 2018 / 181842 contains a very large number of terminal structures per polymer molecule due to its dendritic, highly branched structure. The terminal structures described therein are mostly unsaturated structures of vinyl groups and vinylene groups with diverse structures due to cationic polymerization, resulting in problems with heat stability. In particular, the relatively large number of vinylene groups remain in the cured product even after the curing reaction, which worsens the heat stability after curing, and this problem has not been solved. In other words, if there are many unsaturated groups such as vinylene groups in the hardened material, they will combine and react with oxygen in the air, resulting in an increase in the dielectric constant and dielectric loss tangent of the hardened material, which is undesirable.

[0060] Furthermore, Japanese Patent Publication No. 2018-39995 also describes a cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer according to the prior art, obtained by a similar cationic polymerization. Although this patent document does not describe the terminal structure, it employs a manufacturing method similar to that of International Publication No. 2018 / 181842, and the majority of the resulting polymer consists of aromatic polyene and aromatic vinyl compound units, containing a high content of aromatic polyene (divinylbenzene) units. Since the molecular weight distribution (Mw / Mn) is similarly large, it is considered to have a terminal structure similar to that described in International Publication No. 2018 / 181842, and to have a dendritic, multi-branched structure. Because a cyclic olefin structure is present in part of the terminal structure, it is possible to reduce the proportion of the terminal unsaturated groups, and the increase in dielectric constant and dielectric loss tangent after heat resistance testing is also reduced compared to the case without cyclic olefins, but this is still considered insufficient. In contrast to the dendritic structures with many terminal groups found in conventional technologies, the copolymers of the present invention have a relatively linear structure, with a small number of terminal structures in a single copolymer molecule, and cyclic olefins are not unevenly distributed at the ends of the copolymer. Therefore, the number of cyclic olefin terminals contained in a single copolymer molecule can generally be less than 1.5.

[0061] The α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer of the present invention can be sufficiently cured by curing it alone. Here, curing alone means adding a curing agent (peroxide or other radical polymerization initiator) in an amount of 1 part by mass or less to 100 parts by mass of the copolymer and performing curing treatment under curing conditions appropriate for the peroxide used. The degree of curing can be evaluated by the gel content, which is higher than 50%, preferably 90% or more, and particularly preferably 95% or more. The cured product exhibits excellent low dielectric properties and has a high glass transition temperature, and a cured body with high elastic modulus at room temperature and high temperature can be obtained. Specifically, the dielectric constant of the cured body is 3.5 or less, preferably 2.0 or more and 3.5 or less, more preferably 2.0 or more and less than 3.5, and even more preferably 2.0 or more and less than 2.5. The dielectric loss tangent of the cured body is less than 0.001, preferably 0.0002 or more and less than 0.001, and substantially 0.0005 or more and less than 0.001. The glass transition temperature is arbitrary, but can be between 100°C and 350°C, preferably between 130°C and 300°C. The storage modulus measured at 25°C can be 1000 MPa or higher, and the storage modulus measured at 280°C can be 1 MPa or higher, more preferably 5 MPa or higher. Here, the gel content is a value obtained in accordance with the aforementioned JIS K6796:1998 (or ASTM D2765-84 corresponding to ISO 10147:1994), and the dielectric constant and dielectric loss tangent are values ​​obtained at 25°C and 40 GHz. The glass transition temperature and storage modulus at each temperature are obtained by dynamic viscoelasticity measurement (DMA) at a measurement frequency of 1 Hz. Therefore, even in cured products obtained by curing compositions containing this copolymer, it is possible to obtain cured products with a sufficiently high gel content, and these cured products can exhibit excellent low dielectric properties, a high glass transition temperature, and a high storage modulus at room temperature and high temperatures.

[0062] <Composition containing the polymer of the present invention> The copolymer of the present invention can be cured on its own, but it may also be combined with other materials to form a composition, and this composition can also be cured. The other materials may include the following: "resin components," "curing agents," "monomers," "another olefin-aromatic vinyl compound-aromatic polyene copolymer that does not contain cyclic olefins," "solvents," "fillers," "other additives," etc.

[0063] <Resin components> Any resin component can be used as long as it does not impair the effects of the present invention, but preferably one or more selected from hydrocarbon elastomers, polyether resins, aromatic polyene resins, and olefin-aromatic vinyl compound-aromatic polyene copolymers that do not contain cyclic olefins can be used. Among these, hydrocarbon elastomers and olefin-aromatic vinyl compound-aromatic polyene copolymers that do not contain cyclic olefins are more preferred. Among hydrocarbon elastomers, conjugated diene polymers are preferred. Among conjugated diene polymers, 1,2-polybutadiene is preferred. The amount of the resin component may be in the range of 1 to 500 parts by mass, more preferably 1 to 300 parts by mass, per 100 parts by mass of the copolymer of the present invention.

[0064] <Hydroxide-based elastomers> Hydrocarbon elastomers suitable for use in the compositions 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 ethylene-based and propylene-based elastomers, conjugated diene polymers, aromatic vinyl compound-conjugated diene block copolymers or random copolymers, and one or more elastomers selected from their hydrides (hydrogenated products). Examples of ethylene-based elastomers include ethylene-αolefin copolymers such as ethylene-octene copolymer and ethylene-1-hexene copolymer, EPR, and EPDM. Examples of propylene-based elastomers include atactic polypropylene, low stereoregularity polypropylene, and propylene-αolefin copolymers such as propylene-1-butene copolymer. These hydrocarbon elastomers may be modified by introducing functional groups with maleic anhydride or other compounds.

[0065] <Conjugated diene polymers> Examples of conjugated diene polymers include polybutadiene and 1,2-polybutadiene. Examples of aromatic vinyl compound-conjugated diene block copolymers or random copolymers, and their hydrides (hydrogenated products), include SBS, SIS, SEBS, SEPS, SEEPS, SEEBS, etc. Suitable 1,2-polybutadiene is available, for example, as a product of JSR Corporation, and also from Nippon Soda Co., Ltd. under the product names B-1000, 2000, and 3000. Another example of a suitable copolymer containing a 1,2-polybutadiene structure is "Ricon 100" from TOTAL CRAY VALLEY. These conjugated diene polymers and their hydrides may be modified by introducing functional groups with maleic anhydride or other compounds. Among conjugated diene polymers, conjugated diene copolymers are preferred. Among these conjugated diene copolymers, hydrides of block copolymers such as SEBS, SEPS, SEEPS, and SEEBS are useful as compatibilizers between the copolymer of the present invention and other resin components. These are available from Asahi Kasei under the trade names ToughTec or SOE-SS, from Kuraray under the trade name Septon, and from Kraton under the trade name Kraton.

[0066] <Polyether resin> Examples of polyether resins include polyphenylene ether and polyether. For polyphenylene ether having functional groups, it is preferable that the molecular ends are modified with functional groups. Furthermore, when added for the purpose of curing the composition of the present invention, it is preferable that the molecule has multiple functional groups. For example, modified polyphenylene ether is preferable. Examples of functional groups include radically polymerizable functional groups and epoxy groups, with radically polymerizable functional groups being preferable. Among radically polymerizable functional groups, vinyl groups are preferred. As vinyl groups, one or more from the group consisting of allyl groups, (meth)acryloyl groups, and aromatic vinyl groups are preferred, one or more from the group consisting of (meth)acryloyl groups and aromatic vinyl groups are more preferred, and aromatic vinyl groups are most preferred. In other words, in the composition of the present invention, a bifunctional polyphenylene ether in which both ends of the molecular chain are modified with radically polymerizable functional groups is particularly preferred. Examples of such polyphenylene ethers include Noryl(trademark) SA9000 from SABIC Corporation (a modified polyphenylene ether with methacryloyl groups at both ends, number average molecular weight 2200) and a bifunctional polyphenylene ether oligomer from Mitsubishi Gas Chemical Corporation (OPE-2St, a modified polyphenylene ether with vinylbenzyl groups at both ends, number average molecular weight 1200). In addition, allylated PPE from Asahi Kasei Corporation and aromatic polyethers from JSR Corporation (ELPAC HC-F series) can also be used. Among these, the bifunctional polyphenylene ether oligomer from Mitsubishi Gas Chemical Corporation (OPE-2St) and the aromatic polyethers from JSR Corporation (ELPAC HC-F series) can be used.

[0067] <Aromatic polyene resins> Aromatic polyene resins include divinylbenzene-based reactive polybranched copolymers (PDV or ODV) manufactured by Nippon Steel Chemical & Material Co., Ltd. Such copolymers are described, for example, in the literature "Synthesis of polyfunctional aromatic vinyl copolymers and development of novel IPN-type low dielectric loss materials using them" (Masayoshi Kawabe et al., Journal of the Electronics Packaging Society of Japan, p. 125, Vol. 12 No. 2 (2009)).

[0068] <Another olefin-aromatic vinyl compound-aromatic polyene copolymer that does not contain cyclic olefins> Another olefin-aromatic vinyl compound-aromatic polyene copolymer that does not contain a cyclic olefin and can be used in the present invention is an olefin-aromatic vinyl compound-aromatic polyene copolymer that satisfies all of the following conditions (A) to (E). (A) The number-average molecular weight of the copolymer is between 500 and 100,000. (B) The olefin monomer unit is one or more selected from α-olefins having 2 to 20 carbon atoms, and this olefin does not contain cyclic olefins. (C) The aromatic vinyl compound monomer unit is an aromatic vinyl compound having 8 to 20 carbon atoms, and the content of the aromatic vinyl compound monomer unit is 0 to 90% by mass. (D) The aromatic polyene monomer unit is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl and / or vinylene groups in the molecule, and the content of vinyl and / or vinylene groups derived from the aromatic polyene unit is 2 to 30 per number average molecular weight. The content of vinyl and / or vinylene groups derived from the aromatic polyene unit may be 2 to less than 30 per number average molecular weight. (E) The total of olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass. The details of each monomer of the α-olefin, aromatic vinyl compound, and aromatic polyene are as described above. Such copolymers are specifically described in Japanese Patent Publication No. 2009-161743, International Publication No. 2021 / 112087, International Publication No. 2021 / 112088, and International Publication No. 2022 / 014599. However, as mentioned above, these other copolymers do not contain cyclic olefins. Among olefin-aromatic vinyl compound-aromatic polyene copolymers that do not contain cyclic olefins, copolymers in which the aromatic vinyl compound monomer content is 0 to 60% by mass are particularly soft, and are therefore preferred when incorporated into the copolymer of the present invention, as they can improve the toughness of the resulting cured product and suppress cracking.

[0069] <Hardening agent> The curing agent that may be included in this composition may be any known curing agent that can be used for the polymerization or curing of aromatic polyenes and aromatic vinyl compounds. Examples of such curing agents include radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators, but radical polymerization initiators can be preferably used. Preferably, these are organic peroxide-based (peroxide) or azo polymerization initiators, and can be freely selected depending on the application and conditions. A catalog listing organic peroxides can be found on the NOF Corporation website, for example. https: / / www.nof.co.jp / product-search / family / 1020001 It can be downloaded from [website / platform name]. Organic peroxides are also listed in catalogs from Fujifilm Wako Pure Chemical Industries, Ltd. and Tokyo Chemical Industries, Ltd. The curing agents used in this invention can be obtained from these companies. Furthermore, hydrocarbon-based radical polymerization initiators that do not contain oxygen or nitrogen atoms in their structure, i.e., those composed only of carbon and hydrogen atoms, such as 2,3-dimethyl-2,3-diphenylbutane, can also be suitably used. When a cured product is manufactured using such a hydrocarbon-based radical polymerization initiator, a cured product with a lower dielectric constant and dielectric loss tangent that does not contain oxygen or nitrogen atoms can be obtained, and the low dielectric properties of the cured product can be further improved. In addition, known photopolymerization initiators that use light, ultraviolet light, or radiation can also be used as curing agents. Examples of curing agents that use photopolymerization initiators include photoradical polymerization initiators, photocationic polymerization initiators, or photoanionic polymerization initiators. Such photopolymerization initiators can be obtained, for example, from Tokyo Chemical Industries, Ltd. Furthermore, curing by radiation or electron beams themselves is also possible. In addition, it is also possible to perform crosslinking and curing by thermal polymerization of the raw materials without using a curing agent.

[0070] There are no particular restrictions on the amount of curing agent used, but generally, 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 curing agents such as peroxides or azo polymerization initiators, the curing treatment should be performed at an appropriate temperature and time, taking into account the half-life of the curing agent. The conditions in this case are arbitrary depending on the curing agent, but generally, a temperature range of about 50°C to 180°C is appropriate.

[0071] <Monomer> The amount of monomer that may be included in the composition of the present invention is arbitrary, but preferably 300 parts by mass or less per 100 parts by mass of copolymer. The composition may also be substantially free of monomers. If monomers are included, 1 part by mass or more is preferred, and 5 parts by mass or more is more preferred. In particular, if the monomer content is 30 parts by mass or less, the uncured composition is less likely to become viscous, making it easier to mold as a thermoplastic resin. Furthermore, if the content of easily volatile monomers is below a certain level, odor at the uncured stage is not a problem. When a solvent is added to the composition to create a varnish-like product, there is a problem that monomers are lost with the evaporation of the solvent during use, and the effective monomer content tends to decrease. Also, if the product is an uncured sheet, if the monomer content is below a certain amount, changes in the monomer content during storage are less likely. Monomers that can be suitably used in the composition of the present invention preferably have a molecular weight of less than 1000, and more preferably less than 500. Monomers that can be suitably used in the compositions of the present invention are the aromatic vinyl compound monomer, the aromatic polyene monomer, the aromatic vinylene monomer listed below, and / or the polar monomer listed below. The monomer is preferably one that can be polymerized using a radical polymerization initiator, and more preferably one or more from the group consisting of aromatic vinyl compounds and aromatic polyenes. Furthermore, BVPE (1,2-bis(vinylphenyl)ethane) described in Japanese Patent Application Publication No. 2003-212941 can also be suitably used.

[0072] <Aromatic vinylene monomer> The aromatic vinylene monomers that may be included in the present invention refer to compounds having a single aromatic ring or multiple fused aromatic rings having 9 to 30 carbon atoms, and a vinylene group. Examples of such aromatic vinylene compounds include indenes, beta-substituted styrenes, and acenaphthenes. Examples of indenes include indene, various alkyl-substituted indenes, and phenyl-substituted indenes. Examples of beta-substituted styrenes include β-alkyl-substituted styrenes such as β-methylstyrene, or phenyl-substituted styrenes. Examples of acenaphthenes include acenaphthenes, various alkyl-substituted acenaphthenes, and various phenyl-substituted acenaphthenes. As aromatic vinylene compounds, the above-exemplary compounds may be used individually or in combination of two or more. From the viewpoint of industrial availability and radical polymerization properties, acenaphthenes are most preferred as aromatic vinylene compounds.

[0073] <Polar monomers> A relatively small amount of polar monomer can be used to impart adhesion to other materials necessary for insulating materials. Examples of the above-mentioned polar monomers include various maleimides, bismaleimides, maleic anhydride, glycidyl (meth)acrylate, triallyl isocyanurate, tri(meth)acryl isocyanurate, trimethylolpropane tri(meth)acrylate, etc. Maleimides and bismaleimides usable in the present invention are described, for example, in International Publication No. 2016 / 114287 and can be purchased, for example, from Yamato Chemical Co., Ltd. These maleimide group-containing compounds may also be used as polyaminobismaleimide compounds from the viewpoint of solubility in organic solvents, high-frequency characteristics, high adhesion to conductors, and moldability of prepregs. Polyaminobismaleimide compounds can be obtained, for example, by a Michael addition reaction between a compound having two maleimide groups at its terminus and an aromatic diamine compound having two primary amino groups in its molecule. When aiming to obtain high crosslinking efficiency with a small amount of additive, it is preferable to use polar monomers having two or more polyfunctional groups, such as bismaleimides, triallyl isocyanurate (TAIC), and trimethylolpropane tri(meth)acrylate. The amount of polar monomer that may be included in the composition may be in the range of 0.1 to 30 parts by mass, preferably 0.1 to 10 parts by mass, per 100 parts by mass of copolymer. Using 30 parts by mass or less will result in lower dielectric constant and dielectric loss tangent 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 loss tangent is 1.2 × 10⁻⁶. -3 It is possible to keep it to the following levels.

[0074] <Solvent> A suitable 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. As a solvent, a solvent with a boiling point above a certain level is preferred, because a high boiling point at atmospheric pressure, i.e., low volatility, results in a more uniform thickness of the applied film. A preferred boiling point is 100°C or higher at atmospheric pressure, more preferably 130°C to 300°C. Suitable solvents 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 solvents, the amount used is preferably in the range of 10 to 2000 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. It is preferable to remove the solvent by drying or the like before curing the composition.

[0075] <Filler> Inorganic or organic fillers may be added as needed. These fillers are added for purposes such as controlling the coefficient of thermal expansion, controlling thermal conductivity, and reducing costs, and the amount added is arbitrary depending on the purpose. The composition of the present invention can contain a particularly large amount of inorganic filler, and the maximum amount that can be added is 2000 parts by mass per 100 parts by mass of copolymer. When adding inorganic fillers, it is particularly preferable to use known surface modifiers, such as silane coupling agents. In particular, when aiming for a composition with excellent low dielectric constant and low dielectric loss, which is one of the objectives of the present invention, boron nitride (BN) is preferred as the inorganic filler. From the viewpoint of low dielectric properties, adding a large amount will particularly increase the dielectric constant, so it is preferable to use less than 500 parts by mass of filler per 100 parts by mass of copolymer, and more preferably less than 400 parts by mass. Furthermore, hollow fillers or fillers with a shape containing many voids may be added to improve and enhance the low dielectric properties (low dielectric constant, low dielectric loss loss tangent).

[0076] Furthermore, instead of inorganic fillers, organic fillers such as high molecular weight polyethylene, ultra-high molecular weight polyethylene, polystyrene, styrene-divinylbenzene copolymer, or fluororesins can be used. As for fluororesins, any known resin containing fluorine, such as PTFE (polytetrafluoroethylene) or PFA (perfluoroalkoxyalkane), can be used. An example of such a resin is AGC's Fluon+(registered trademark) EA-2000. If 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 viewpoint of heat resistance that the organic filler itself is crosslinked, and it is preferable that it be formulated in the form of fine particles or powder. These organic fillers can also suppress the increase in dielectric constant and dielectric loss tangent.

[0077] On the other hand, by mixing and dispersing a high dielectric constant insulating filler having a dielectric constant of preferably 3 to 10,000, more preferably 5 to 10,000, at 1 GHz into the composition of the present invention, it is possible to create an insulating cured body having a high dielectric constant insulating layer with a dielectric constant of preferably 2.5 to 20, and even more preferably 2.8 to 10, while suppressing an increase in dielectric loss tangent (dielectric loss). By increasing the dielectric constant of the film made of the insulating cured body, it is possible to miniaturize circuits and increase the capacitance of capacitors, which can contribute to the miniaturization of high-frequency electrical components. The high dielectric constant, low dielectric loss tangent insulating layer is 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 undergone insulating treatment. Specific examples include known high dielectric constant inorganic fillers such as barium titanate and strontium titanate, and other examples are specifically described in, for example, Japanese Patent Application Publication No. 2004-087639.

[0078] <Other additives> This composition may further contain one or more selected from flame retardants and surface modifiers. The composition of the present invention can serve as the matrix of a cured body and, in order to have excellent filling properties for other materials when cured, 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.

[0079] <Flame retardant> Known flame retardants can be used in the compositions of the present invention. Preferred flame retardants, from the viewpoint of maintaining a low dielectric constant and low dielectric loss tangent, are known organophosphorus compounds such as phosphate esters or condensates thereof, known brominated flame retardants, and red phosphorus. Among phosphate esters in particular, compounds having multiple xylenyl groups in the molecule are preferred from the viewpoint of flame retardancy and low dielectric loss tangent.

[0080] Furthermore, in addition to flame retardants, antimony compounds such as antimony trioxide, antimony tetroxide, 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-triallyloxy-1,3,5-triazine may be added as flame retardant aids. 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. Alternatively, a polyphenylene ether (PPE)-based resin with low dielectric constant and excellent flame retardancy may be used in amounts of 30 to 200 parts by mass per 100 parts by mass of the flame retardant.

[0081] <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 surface modifier used is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the composition of the present invention other than the surface modifier. Examples of surface modifiers include various silane coupling agents and titanate coupling agents. One or more of the various silane coupling agents and titanate coupling agents may be used.

[0082] In the present invention, the fluidization temperature of the curable resin or composition can be adjusted according to its purpose and molding method by changing the mixing ratio of "resin components," "curing agents," "monomers," "solvents," "fillers," or "other additives." Specifically, the composition of the present invention can take the form of a "thermoplastic composition," a "semi-cured state (B-stage sheet, etc.)," ​​or a "varnish."

[0083] The compositions of the present invention are obtained by mixing, dissolving, or melting one or more selected from "resin components," "curing agents," "monomers," "solvents," "fillers," and "other additives." Furthermore, common additives that are normally added to resins, such as lubricants, stabilizers, antioxidants, weathering agents, and UV absorbers, can be used to the extent that the objectives of the present invention are not hindered. Any known method can be used for mixing, dissolving, or melting these components.

[0084] <Thermoplastic composition and its molded article> The composition of the present invention can exhibit the properties of a thermoplastic resin when it uses a copolymer having a molecular weight above a certain level, generally in the range of approximately 50,000 or more in weight-average molecular weight, and also contains the predetermined resin component. Therefore, under conditions that do not cause crosslinking, it can be molded into shapes such as sheets, tubes, strips, and pellets in a substantially uncured state by known molding methods for thermoplastic resins. The molded article may be crosslinked (cured) thereafter or during molding.

[0085] Furthermore, preferred embodiments of this composition are as follows: If the resin component contains one or more resins selected from the hydrocarbon elastomer, polyether resin, olefin-aromatic vinyl compound-aromatic polyene copolymer that does not contain cyclic olefins, or aromatic polyene resin, in a certain proportion or more, excluding the resin that is liquid at room temperature, it will similarly be easy to mold as a thermoplastic resin in its uncured state. The above thermoplastic composition may be used to take advantage of its thermoplasticity at a temperature below the curing agent's operating temperature, be pre-formed into various shapes such as sheets, and then, if necessary, laminated and combined with semiconductor elements, wiring, or substrates before being heat-cured and bonded.

[0086] The composition of the present invention may be provided as a sheet formed by a known method from a composition that has been heated and melted at a temperature below or equal to the curing agent's action temperature or decomposition temperature. Forming into a sheet may be done by T-die extrusion, double-roll molding, or extrusion lamination onto a substrate film. In this case, the composition, copolymer / monomer mass ratio, solvent, resin component, and flame retardant are selected and adjusted so that the composition melts at or below the curing agent's action temperature or decomposition temperature and becomes solid at around room temperature. In this case, the sheet is substantially uncured. Subsequently, after various processing and assembly steps, it is finally treated at a temperature and time above the curing agent's action temperature or decomposition temperature to achieve complete curing. Such a method is a common technique used for ethylene-vinyl acetate resin-based crosslinked encapsulant sheets in solar cells (photovoltaic power generation devices).

[0087] <Molded body in a semi-cured state (e.g., B-stage sheet)> Furthermore, the composition of the present invention can also be formed into a partially crosslinked state, for example, a partially cured state (so-called B-stage state) by reacting a portion of the curing agent contained therein, such as a sheet or tube. Here, the partially cured state is defined independently of the definition of the uncured state above, 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 less than or equal to 80% by mass. 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, partial curing can be achieved, and the melt viscosity and fluidity can be controlled to reach the B-stage state. That is, by the first stage of curing (partial curing), the curable resin or composition can be molded into an easy-to-handle B-stage sheet, which can then be laminated and pressed onto an electronic device or substrate, and then a second stage of curing (complete curing) can be performed to obtain the final shape. In this case, the composition, i.e., the mass ratio of copolymer to monomer, is selected, and if necessary, solvents, resin components, and flame retardants are added. The composition, which also contains a curing agent such as a peroxide, is partially cured to adjust it into a sheet shape (B-stage state), and after molding and assembling the device, it can be heated under pressure to achieve complete curing. Known methods can be used to partially cure the composition. For example, one method involves using peroxides with different decomposition temperatures, treating the material at a temperature where only one of them is substantially active for a predetermined time to obtain a semi-cured sheet, and finally treating it at a temperature where all the curing agents are active for a sufficient amount of time to achieve complete curing.

[0088] Furthermore, the molded product may be a sheet. The sheet may be uncured (semi-cured) to the extent that it can maintain its sheet shape, or it may be fully cured. The degree of curing of the composition can be quantitatively measured by a known dynamic viscoelasticity measurement method (DMA, Dynamic Mechanical Analysis).

[0089] The composition of the present invention can also be made into a viscous liquid varnish depending on its composition and mixing ratio. For example, it can be made into a varnish by using a sufficient amount of solvent and / or by using an appropriate amount of liquid monomer. In particular 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. As for the solvent, a solvent with a boiling point above a certain level is preferable, because a high boiling point at atmospheric pressure, i.e., low volatility, results in a uniform thickness of the applied film. The preferred boiling point is generally between 110°C and 300°C at atmospheric pressure. Suitable solvents 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 used is preferably in the range of 10 to 2000 parts by mass per 100 parts by mass of the composition of the present invention.

[0090] The varnish can be applied to or impregnated onto a substrate, for example, and the solvent can be removed by drying to produce an uncured or semi-cured molded body. Generally, this molded body takes the form of a sheet, film, or tape. In this embodiment, the obtained uncured or semi-cured molded body is cured.

[0091] <Curing> The composition can be cured by known methods, taking into account the curing conditions (temperature, time, pressure) of the curing agent it contains. If the curing agent used is a peroxide, the curing conditions can be determined by referring to the half-life temperature and other parameters disclosed for each peroxide.

[0092] <Cured 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 is 3.5 or less, preferably 3.5 or less and 2.0 or more, and particularly preferably 3.0 or less and 2.0 or more. The dielectric loss tangent of the cured product is 0.0015 or less, preferably 0.0002 or more and 0.0015 or less, and preferably 0.0005 or more and 0.0010 or less. The volume resistivity of the cured product is preferably 1 × 10⁻⁶. 15 The coefficient of elasticity is Ω·cm or greater. These values ​​are preferable, for example, for electrical insulating materials used at high frequencies of 3 GHz or higher. Because the copolymer used in the composition of the present invention is relatively soft and has high tensile elongation, the cured body obtained from the composition using it can exhibit sufficient mechanical properties while having relatively high impact resistance and the ability to follow the thermal expansion of the substrate. That is, the storage modulus of the cured body of the present invention is preferably 0.1 GPa or less, more preferably 0.1 GPa or less, less than 30 GPa, and even more preferably 1 GPa or more and 20 GPa or less, as measured at room temperature (25°C). Furthermore, the storage modulus of elasticity 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, as measured at high temperature (280°C). Those skilled in the art can determine the formulation of a composition having the above physical property parameters and prepare a cured body by referring to the information described herein and in publicly available materials. The cured product obtained from the composition of the present invention can exhibit practically sufficient heat resistance and mechanical properties at high temperatures, even under conditions where the monomers in the composition and aromatic polyenes as monomer components are kept below a certain percentage.

[0093] <General uses of the composition> The compositions of the present invention can be used as substrates and substrates, such as single-layer or multi-layer printed circuit boards, flexible printed circuit boards, so-called single-layer or multi-layer CCL (copper-clad laminate) substrates, and single-layer or multi-layer FCCL (flexible copper-clad laminate) substrates. They can also be used as various electrical insulating materials for wiring, preferably for 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.

[0094] In another aspect, the present invention comprises an olefin-aromatic vinyl compound-aromatic polyene copolymer (which may be an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer), and the cured product has a storage modulus of 10 MPa or more and 10 GPa or less at 250°C, a dielectric constant of 3.5 or less and 2.0 or more as measured at 23°C and 40 GHz, and a dielectric loss tangent of 0.0015 or less, more preferably 1.2 × 10 -3 The following electrical insulating materials can be provided.

[0095] In one embodiment of the present invention, a method for producing the above copolymer can also be provided. This method involves copolymerizing the monomers of α-olefin, cyclic olefin, and aromatic polyene by coordination polymerization. In another embodiment, a method for producing a cured product can also be provided, which includes the step of polymerizing the above copolymer with a radical polymerization initiator composed only of carbon atoms and hydrogen atoms, and not containing oxygen or nitrogen atoms in its structure.

[0096] Coordination polymerization is a polymerization method that uses a coordination polymerization catalyst consisting of a transition metal compound and a co-catalyst. Preferred transition metal compounds include zirconium, hafnium, titanium, iron, nickel, cobalt, and palladium. In particular, for copolymerizing cyclic olefin monomers, transition metal compounds containing zirconium, titanium, nickel, iron, and palladium are preferred. Most preferably, the coordination polymerization catalyst used is one consisting of a transition metal compound represented by the following general formula (1) and a co-catalyst. More preferably, the production method includes a step of copolymerizing α-olefins, cyclic olefins, aromatic vinyl compounds (if present), and aromatic polyene monomers using a polymerization catalyst consisting of a transition metal compound represented by the following general formula (1) and a co-catalyst.

[0097] General formula (1) [ka] In the above formula, A and B are each independently 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 a methylene group, silylene group, ethylene group, germylene group, or boron residue that has bonds with A and B and also has 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 from each other or the same. Also, Y may have a cyclic structure. Most preferably, Y is a methylene group that has bonds with A and B and also has 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. X is hydrogen, a 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 1 to 4 carbon atoms with a hydrocarbon substituent, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having 1 to 6 carbon atoms with an alkyl substituent. M is a transition metal, preferably zirconium, hafnium, or titanium.

[0098] To obtain copolymers with relatively low molecular weight and low viscosity when made into varnish, preferably, A and B in the above general formula (1) may each be independently selected from unsubstituted or substituted cyclopentadienyl groups or unsubstituted or substituted indenyl groups, and it is particularly preferable to use a transition metal compound having both unsubstituted or substituted cyclopentadienyl groups and unsubstituted or substituted indenyl groups. To obtain copolymers with a high aromatic polyene content, that is, copolymers with 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 unsubstituted or substituted indenyl groups and unsubstituted or substituted benzoindenyl groups. In the case of copolymers with a high aromatic polyene content, it is possible to increase the crosslinking density of the cured product obtained by curing, and for example, a cured product with a storage modulus of 5 MPa or higher measured at 280°C can be obtained.

[0099] As co-catalysts in the polymerization catalyst of the present invention, known co-catalysts used in combination with transition metal compounds can be used. Preferably, such co-catalysts include aluminum compounds and boron compounds. As aluminum compounds, almoxanes such as methylaluminoxane (or methylalmoxane or MAO) are preferably used. Alkylaluminum such as triisobutylaluminum or triethylaluminum may also be used. Examples of such co-catalysts include co-catalysts and alkylaluminum compounds described in European Patent Application Publication No. 0872492A2, Japanese Patent Publication No. 11-130808, Japanese Patent Publication No. 9-309925, International Publication No. 00 / 20426, European Patent Application Publication No. 0985689A1, and Japanese Patent Publication No. 6-184179.

[0100] Examples of boron compounds include trispentafluorophenylborane, triphenylcarbeniumtetrakis(pentafluorophenyl)borate {trityltetrakis(pentafluorophenyl)borate}, lithiumtetrakis(pentafluorophenyl)borate, trimethylammoniumtetraphenylborate, triethylammoniumtetraphenylborate, tripropylammoniumtetraphenylborate, tri(n-butyl)ammoniumtetraphenylborate, tri(n-butyl)ammoniumtetra(p-tolyl)phenylborate, tri(n-butyl)ammoniumtetra(p-ethylphenyl)borate, tri(n-butyl)ammoniumtetra(pentafluorophenyl)borate, trimethylammoniumtetra(p-tolyl)borate, trimethylammoniumtetrakis-3,5-dimethylphenylborate, and triethylammoniumtetrakis-3 ,5-dimethylphenyl borate, tributylammonium tetrakis-3,5-dimethylphenyl borate, tributylammonium tetrakis-2,4-dimethylphenyl borate, anilinium tetrakispentafluorophenyl borate, N,N'-dimethylanilinium tetraphenyl borate, 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 tetraphenyl borate, N,N'-2,4These include 5-pentaethylanilinium tetraphenylborate, di-(isopropyl)ammonium tetrakispentafluorophenylborate, dicyclohexylammonium 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. The most preferred boron co-catalyst among these is one having boron and a fluorine-substituted aromatic group bonded to it. Examples of such co-catalysts include trispentafluorophenylborane, triphenylcarbeniumtetrakis(pentafluorophenyl)borate {trityltetrakis(pentafluorophenyl)borate}, lithiumtetrakis(pentafluorophenyl)borate, tri(n-butyl)ammoniumtetra(pentafluorophenyl)borate, tropyliumtetrakispentafluorophenylborate, and N,N'-dimethylaniliniumtetrakis(pentafluorophenyl)borate. While a phenyl group is used as an example of a fluorine-substituted aromatic group here, condensed aromatic groups such as naphthyl groups, also fluorine-substituted, can be preferably used.

[0101] The co-catalyst is used in a ratio of aluminum atoms to transition metal atoms of 0.1 to 100,000, preferably 10 to 10,000, relative to the metal of the transition metal compound. A ratio of 0.1 or higher effectively activates the transition metal compound, while a ratio of 100,000 or lower is economically advantageous. The transition metal compound and co-catalyst may be mixed and prepared outside the polymerization equipment, or mixed inside the equipment during polymerization.

[0102] In particular, for co-catalysts such as almoxanes, the aluminum atom / transition metal atom ratio with respect 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 higher effectively activates the transition metal compound, while a ratio of 100,000 or lower is economically advantageous. When using a boron compound as a co-catalyst, the boron atom / transition metal atom 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 higher effectively activates the transition metal compound, while a ratio of 100 or lower is economically advantageous.

[0103] In preferred embodiments, a boron compound is essential, and an aluminum compound may be used as a co-catalyst if necessary. By using a boron compound as a co-catalyst, the amount of metal components such as aluminum derived from the aluminum compound contained in the final copolymer can be reduced, and the dielectric constant and dielectric loss tangent values ​​of the final uncured copolymer, or the dielectric constant and dielectric loss tangent values ​​of the cured body or composition alone, can be reduced to a particularly preferred range. 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 copolymer alone can be less than 2.3 and the dielectric loss tangent can be less than 0.0004.

[0104] In one embodiment, an uncured α-olefin-cyclic olefin-aromatic polyene copolymer or α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer can be provided, having a total metal content from the catalyst and co-catalyst of 1000 ppm or less, preferably 750 ppm or less, and most preferably 500 ppm or less. Here, the metal content from the catalyst and co-catalyst is defined as the sum of the respective contents of the transition metal elements used in the catalyst (as described above) and the boron and / or aluminum derived from the boron and / or aluminum compounds used in the co-catalyst, and can be defined as the sum of the elemental contents of zirconium, hafnium, titanium, iron, nickel, palladium, cobalt, boron, and aluminum. Particularly preferably, the metal from the catalyst may be zirconium, and the metal from the co-catalyst may be aluminum and boron, and the metal content from the catalyst and co-catalyst may be the sum of the respective contents of zirconium, aluminum, and boron. In this specification, boron is included in the category of metals. 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 1000 ppm or less, preferably 750 ppm or less, and most preferably 500 ppm or less, can exhibit one or more of the following characteristics: a dielectric constant of less than 2.3 at a measurement frequency of 40 GHz, a dielectric loss tangent of less than 0.0004 at a measurement frequency of 40 GHz, and a storage modulus of 1000 MPa or more measured at 25°C. More preferably, the uncured copolymer may have a dielectric constant of less than 2.3 and a dielectric loss tangent of less than 0.0004 at a measurement frequency of 40 GHz, and a storage modulus of 1000 MPa or more measured at 25°C. [Examples]

[0105] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0106] The copolymers obtained in the synthesis examples were analyzed by the following methods. The determination of the content of vinyl group units derived from ethylene, cyclic olefin, and divinylbenzene in the copolymer was carried out by 1 H-NMR measurement and 13 C-NMR measurement in the quantitative mode, and was performed by a known method from the area intensity of the obtained peaks. The sample was dissolved in 1,1,2,2-tetrachloroethane, and the measurement was carried out at 80 - 130 °C.

[0107] The molecular weight was determined as the number average molecular weight (Mn) in terms of standard polystyrene using GPC (gel permeation chromatography). The measurement was carried out under the following conditions.

[0108] Column: Two TSK-GEL MultiporeHXL-M φ7.8×300 mm (manufactured by Tosoh Corporation) were connected in series and used. Column temperature: 40 °C Solvent: THF Liquid feeding flow rate: 1.0 ml / min. Detector: RI detector

[0109] <Viscosity> The viscosity of the copolymer obtained in each example was determined as follows. A 25 mass% toluene solution of each copolymer was prepared, and measured at 25 °C using a rotational rheometer (MCR302: manufactured by Anton Paar), and the value of the shear rate of 1 sec -1 was used.

[0110] <Gel fraction> According to ASTM D2765-84, the gel fraction as the boiling toluene-insoluble content was determined.

[0111] <Water absorption rate> In accordance with ASTM D570-98, the water absorption rate after immersion in pure water at 23 °C for 24 hours was measured.

[0112] <Dielectric constant and dielectric loss (dielectric tangent)> The dielectric loss tangent was measured using the cavity resonator perturbation method (Agilent Technologies 8722ES network analyzer, Keysight Technologies split-cylinder resonator, 40 GHz) with a 0.1 mm × 25 mm × 30 mm sample cut from a sheet, at 23°C and 40 GHz. Measurements were taken for both the uncured and cured states.

[0113] <Measurement of Storage Modulus> A dynamic viscoelasticity analyzer (TA Instruments, formerly Rheometrics RSA-G2) was used to measure the storage modulus at 25°C and 280°C, starting at a frequency of 1 Hz and increasing temperature from room temperature (23°C). Measurement samples (3 mm x 40 mm) were cut from a film approximately 0.1 mm thick, and the storage modulus was measured for both the uncured and cured states. In addition, the glass transition temperature was determined from the peak temperature of the loss tangent (tanδ) in the uncured state. The main measurement parameters involved in the measurement are as follows: Measurement frequency 1Hz Heating rate: 3°C / min Sample measurement length: 10 mm Distortion 0.1%

[0114] <Quantitative determination of metal content in copolymers> The metal content (in the example below, the content of the transition metal elements used in the metal catalyst, and the content of boron and aluminum used in the co-catalysts) was determined as follows. Furthermore, the content of hafnium, titanium, iron, nickel, cobalt, and palladium was also quantified. Measurements were taken by ICP 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 ashed using a hot plate, electric stove, and electric furnace (heated gradually to 600°C). 0.5 ml of HCl(1+1) (i.e., a 1:1 volume mixture of hydrochloric acid and water) and ultrapure water were added to the residue, and after heating and dissolution, the volume was adjusted to 5 ml to prepare the test solution. Quantitative analysis was performed using ICP emission spectrometry (using an Agilent 5110VDV).

[0115] <Example 1: Copolymer Production P-1>

[0116] The raw material used was divinylbenzene (DVB), a product of Nippon Steel Chemical & Material Co., Ltd., named "Divinylbenzene (96%)" (liquid at room temperature, a mixture of meta and para isomers containing 96% by mass of divinylbenzene, with the remainder being ethylvinylbenzene). Norbornene (75% concentration, toluene solution) from Maruzen Petrochemical Co., Ltd. was used as a raw material, and after adding a small amount of triisobutylaluminum (TIBA) and stirring at room temperature, it was purified by distillation under nitrogen. A 10L polymerization vessel equipped with a heating and cooling jacket and a stirrer was used. First, the inside of the polymerization vessel, which had been thoroughly dried, was purged with nitrogen, and 3 kg of toluene, 1 kg of norbornene (as pure content), and 180 g of divinylbenzene (as pure content) were charged in, and approximately 20 L of dry nitrogen was bubbled in at an internal temperature of 50°C. Subsequently, the polymerization chamber was purged with ethylene gas, 5 mmol of TIBA (manufactured by Kanto Chemical Co., Ltd.) was added as aluminum and stirred, and then 50 mmol of MMAO (modified MAO) (manufactured by Tosoh Finechem Co., Ltd.) was added as aluminum and stirred. The internal temperature was stabilized at 60°C, and the internal pressure of the polymerization chamber was increased to 0.4 MPaG (gauge) by supplying ethylene and stabilized. Then, 100 μmol of rac diphenylmethylene (1-indenyl)(cyclopentadienyl) zirconium dichloride (structure is shown in formula (2) below) and 100 g of a toluene solution containing 2 mmol of TIBA were added to the polymerization chamber from a catalyst tank installed on top of the polymerization chamber, and polymerization was started. The polymerization was continued by continuously replenishing the ethylene consumed during polymerization and maintaining an internal temperature of 60°C and an internal pressure of 0.4 MPaG. After approximately 2 hours of polymerization, when the ethylene consumption reached 200 g, the ethylene gas in the polymerization tank was discharged and the pressure returned to atmospheric pressure. 50 g of isopropanol, a polymerization stopper, was added to the polymerization tank to stop the polymerization. The obtained polymerization solution was added in small amounts to a sufficiently large methanol / acetone mixed solution, and the precipitated polymer was stirred and filtered to recover the polymer. The polymer was then thoroughly vacuum-dried at room temperature to obtain P-1, an ethylene-norbornene-divinylbenzene copolymer.

[0117] Formula (2) [ka]

[0118] <Example 2: Copolymer Production P-2> Polymerization was carried out in the same manner as the synthesis of P-1, except that the amount of norbornene used was changed to 1.4 kg as the pure component, and the polymerization was stopped when the ethylene consumption reached 100 g to obtain P-2, which is an ethylene-norbornene-divinylbenzene copolymer.

[0119] <Example 3: Copolymer Production P-3> Polymerization was carried out in the same manner as the synthesis of P-1, except that the amount of raw materials used was changed to 2 kg of toluene, 2 kg of norbornene as pure matter, and 300 g of divinylbenzene as pure matter, and MMAO (modified MAO) manufactured by Tosoh Finechem Co., Ltd. was changed to 100 mmol of aluminum, and the catalyst used was changed to 100 g of a toluene solution containing 200 μmol of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride (structure is shown in formula (3) below) and 4 mmol of TIBA. Polymerization was stopped when the ethylene consumption reached 150 g to obtain P-3, an ethylene-norbornene-divinylbenzene copolymer.

[0120] Formula (3) [ka]

[0121] <Example 4: Copolymer Production P-4> Similar to the synthesis of P-3, dimethylmethylenebis(cyclopentadienyl)zirconium dichloride was used as a catalyst, except that MMAO was not used as a co-catalyst; instead, tritium tetrakis(pentafluorophenyl) borate (manufactured by Tosoh Finechem Co., Ltd.) was used. Specifically, a catalyst solution was prepared by dissolving 125 micromoles of tritium tetrakis(pentafluorophenyl) borate while stirring in 200 ml of a toluene solution containing 110 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 2 mmol of triisobutylaluminum, and polymerization was carried out at an internal temperature of 90°C. Polymerization was stopped when the ethylene consumption reached 150 g to obtain P-4, an ethylene-norbornene-divinylbenzene copolymer.

[0122] Since P-1 to P-4 obtained in each example contained small amounts of residual monomer and solvent, they were redissolved in toluene, and the solutions were added in small amounts to a sufficiently large methanol / acetone mixed solution. The precipitated polymer was stirred, filtered, and dried under vacuum at room temperature for 24 hours to obtain purified polymer. The composition and molecular weight of the obtained P-1 to P-4 are shown in Table 1. The purified polymer was again dissolved in toluene to obtain a 50% by mass toluene solution (varnish). The varnish was applied to a smooth Teflon® plate with an applicator and air-dried at 25°C for more than 3 hours, then dried under vacuum at 120°C for 12 hours, and then dried under vacuum at 200°C for 60 minutes to obtain a transparent sheet with a thickness of 0.1 mm. This sheet was cut into small pieces and the gel content was measured. From the results of this gel content measurement, it was confirmed that the sheet was in an uncured state. The viscoelastic spectrum (DMA) was measured using this sheet, and the storage modulus at 25°C and the glass transition temperature were measured. The dielectric properties were measured using this sheet. These results are shown in Table 1. The copolymer of the present invention exhibits a high glass transition temperature in its uncured state, and shows a high storage modulus (25°C), low dielectric constant, and low dielectric loss tangent. In particular, P-4 obtained using a boron compound as a co-catalyst shows a low dielectric constant and a remarkably low dielectric loss tangent.

[0123] [Table 1a] [Table 1b]

[0124] <Example 5: Preparation of a hardened sheet> Using a container equipped with a heating and cooling jacket and stirring blades, 100 parts by mass of P-1 (ethylene-norbornene-divinylbenzene copolymer) was heated to approximately 50°C and stirred in 100 parts by mass of toluene as a solvent to dissolve the copolymer and prepare a 50% by mass toluene solution (varnish). Furthermore, 1 part by mass of a curing agent (perbutyl P) was added to the copolymer by weight, dissolved, and stirred to obtain a varnish-like composition (Table 2). The obtained composition was poured into a Teflon® mold (frame length 7 cm, width 7 cm, thickness 0.2 mm, 0.5 mm, or 1.0 mm) on a PET sheet placed on a glass plate, thoroughly air-dried at 25°C, and then dried in a vacuum dryer at 60°C for 3 hours or more to obtain an uncured sheet. Furthermore, the Teflon sheet and Teflon mold were placed in a press machine under a load of 5 MPa and heat-treated at 120°C for 30 minutes, 150°C for 30 minutes, and then 200°C for 120 minutes. After removing the Teflon sheet and Teflon mold, a cured sheet was obtained. The gel content, storage modulus (at 25°C and 280°C), dielectric constant, dielectric loss tangent (both measured at 23°C and 40 GHz), and water absorption rate of the obtained cured sheet were determined.

[0125] <Example 6: Preparation of a hardened sheet> A cured sheet was obtained in the same manner as in Example 5, and its physical properties were determined in the same manner.

[0126] <Examples 7-8: Preparation of hardened sheets> For P-3 and P-4, which have glass transition temperatures of 150°C or higher, removing residual toluene from the polymer is more difficult compared to P-1 and P-2. Cured sheets were obtained as follows, and their physical properties were determined in the same manner. Using the same container as in Examples 5 and 6, 100 parts by mass of P-3 or P-4 (ethylene-norbornene-divinylbenzene copolymer) was heated to approximately 50°C and stirred in 100 parts by mass of toluene as a solvent to dissolve the copolymer and prepare a 50% by mass toluene solution (varnish). Furthermore, 1 part by mass of a curing agent (2,3-dimethyl-2,3-diphenylbutane, manufactured by Kanto Chemical Co., Ltd.) was added to the copolymer by weight, dissolved, and stirred to obtain a varnish-like composition (Table 2). The obtained composition was poured into a Teflon® mold (mold length 7cm, width 7cm, thickness 0.1mm) on a PET sheet placed on a glass plate, thoroughly air-dried at 25°C, and then dried in a vacuum dryer at 100°C for 3 hours to obtain an uncured sheet substantially free of solvent. Multiple sheets of this uncured sheet were stacked to the thickness required for each measurement, and the Teflon sheet and Teflon mold were placed in a vacuum press under a load of 5 MPa and heat-treated at 250°C for 60 minutes. The Teflon sheet and Teflon mold were then removed to obtain a cured sheet. The gel content, storage modulus (25°C and 280°C), dielectric constant, dielectric loss tangent (both measured at 23°C and 40 GHz), and water absorption rate of the obtained cured sheet were determined.

[0127] Table 2 shows the formulation (units in the table are parts by mass) and physical properties (gel content, storage modulus at 25°C and 280°C, dielectric constant, dielectric loss tangent, and water absorption). Table 2 also shows the viscosity of a 25% by mass toluene solution (varnish) for each example. The cured sheets obtained in Examples 5-8 showed high gel content and were sufficiently cured. The storage modulus at room temperature (25°C) indicated sufficient hardness for use as a substrate, especially a rigid substrate. Furthermore, they exhibited the low dielectric constant and low dielectric loss tangent required for high-frequency insulating materials. The cured sheets obtained in Examples 5 and 6 showed high storage modulus at high temperatures (280°C) and possessed high mechanical properties at high temperatures. Furthermore, the viscosity of the 25% by mass toluene solution (varnish) containing the copolymers obtained in Examples 5 and 6 was 10,000 mPa·s or less in all cases. The cured sheet obtained in Example 8 showed particularly low dielectric constant (2.1) and dielectric loss tangent (0.0002).

[0128] [Table 2]

[0129] <Example 9: Copolymer Production P-5> Polymerization, polymer recovery, and post-treatment were carried out in the same manner as for the production method of P-4 described above. However, 1.5 kg of norbornene (as pure content), 2.5 kg of toluene, and 200 g of divinylbenzene (as pure content) were charged. As a catalyst, 200 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 5 mmol of triisobutylaluminum were added to 300 ml of a toluene solution, to which 210 micromoles of tritilium tetrakis(pentafluorophenyl) borate were added and stirred to dissolve the catalyst solution. Polymerization was carried out at an internal temperature of 60°C, while maintaining the internal pressure of the polymerization chamber at 0.15 MPaG (gauge) by supplying ethylene. During the process, the same amount of catalyst solution as described above was added again. Polymerization was stopped when the ethylene consumption reached 100 g to obtain P-5, an ethylene-norbornene-divinylbenzene copolymer.

[0130] <Example 10: Production of copolymer P-6> Polymerization, polymer recovery, and post-treatment were carried out in the same manner as for the production method of P-5 described above. However, 1.5 kg of DMON (1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene, manufactured by Maruzen Petrochemical Co., Ltd., purity 98%) was used instead of norbornene. Polymerization was stopped when the ethylene consumption reached 100 g to obtain P-6, an ethylene-MPNB-divinylbenzene copolymer.

[0131] <Example 11: Copolymer Production P-7> Polymerization, polymer recovery, and post-treatment were carried out in the same manner as for the production method of P-5 described above. However, 1.5 kg of MPNB (methylphenylnorbornene, manufactured by Maruzen Petrochemical Co., Ltd., purity 98%) was used instead of norbornene. Polymerization was stopped when the ethylene consumption reached 100 g to obtain P-7, an ethylene-MPNB-divinylbenzene copolymer.

[0132] <Example 12: Copolymer Production P-8> The raw material used was divinylbenzene (DVB), a product of Nippon Steel Chemical & Material Co., Ltd., named "Divinylbenzene (81%)" (liquid at room temperature, a mixture of meta and para isomers containing 81% by mass of divinylbenzene, with the remainder being ethylvinylbenzene). Norbornene (75% concentration, toluene solution) from Maruzen Petrochemical Co., Ltd. was used as a raw material, and after adding a small amount of triisobutylaluminum (TIBA) and stirring at room temperature, it was purified by distillation under nitrogen. A 10L polymerization vessel equipped with a heating and cooling jacket and a stirrer was used. First, the polymerization vessel, which had been thoroughly dried, was purged with nitrogen, and 2 kg of toluene, 1 kg of norbornene (as pure content), and 2 kg of divinylbenzene (as 81% divinylbenzene) were charged in. Approximately 20 L of dry nitrogen was bubbled in at an internal temperature of 50°C. After that, the polymerization vessel was purged with nitrogen gas, and 6 mmol of TIBA (manufactured by Kanto Chemical Co., Ltd.) was added and stirred. After stabilizing the internal temperature at 60°C and increasing the internal pressure of the polymerization vessel to 0.1 MPaG (gauge) using nitrogen and stabilizing it, a catalyst solution was added to the polymerization vessel from a catalyst tank installed on top of the polymerization vessel. This solution consisted of 200 μmol of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride as a catalyst, 100 g of toluene solution containing 2 mmol of TIBA, 210 μmol of tritilium tetrakis(pentafluorophenyl) borate, dissolved and stirred. Polymerization was then started by adding this catalyst solution to the polymerization vessel. Polymerization was continued while maintaining the internal temperature at 60°C and internal pressure at 0.1 MPaG. After 4 hours of polymerization, 50 g of isopropanol, a polymerization stopper, was added to the polymerization vessel to stop the polymerization. The obtained polymerization solution was added in small amounts to a sufficiently large methanol / acetone mixed solution. The precipitated polymer was stirred and filtered to recover the polymer, and then thoroughly vacuum-dried at room temperature to obtain P-8, a norbornene-ethylvinylbenzene-divinylbenzene copolymer.

[0133] <Example 13: Copolymer Production P-9> In a polymerization tank, 2.2 kg of toluene, 1.5 kg of pure DMON, 300 g of styrene, and 200 g of pure divinylbenzene were charged, and copolymerization of ethylene, DMON, styrene, and divinylbenzene was carried out in the same manner as in the production method of P-6. Polymerization was stopped when the ethylene consumption reached 100 g, and post-treatment was performed in the same manner to obtain P-9, an ethylene-MPNB-ethylvinylbenzene-divinylbenzene copolymer.

[0134] Table 1 shows the composition, molecular weight, gel content, glass transition temperature, storage modulus at 25°C, dielectric properties, and metal content of copolymers P-5 to P-9. Copolymers P-5 to P-9, obtained using a boron compound as a co-catalyst, exhibit a high glass transition temperature in the uncured state, a high storage modulus (25°C), and remarkably low dielectric constant and dielectric loss tangent.

[0135] Copolymers obtained using DMON or MPNB as cyclic olefins can yield high glass transition temperatures even with relatively low molar contents of DMON or MPNB. Specifically, the DMON content of P-6 is 52 mol%, and the MPNB content of P-7 is 46 mol%, which are lower molar contents than the norbornene content of P-5 (74 mol%). However, the glass transition temperatures are 198°C for P-6 and 186°C for P-7, which are almost equivalent to the 190°C of P-5. When the molar content of the cyclic olefin component is relatively low, it becomes easier to replace the remaining monomer components with aromatic vinyl compound units, making it possible to obtain copolymers with a higher aromatic vinyl compound unit content. That is, it is possible to increase the aromaticity of the copolymer while maintaining a high glass transition temperature, which is preferable because it improves compatibility with other resins and raw materials. An example is shown in P-9. MPNB is particularly preferable in this respect because the cyclic olefin itself possesses aromatic groups. Furthermore, copolymers obtained using DMON or MPNB as the cyclic olefin exhibit a similarly high glass transition temperature while having a lower molecular weight. Specifically, by using DMON or MPNB as the cyclic olefin, a number-average molecular weight of 12,000 or less, which is most preferable, can be easily achieved. The ease of reducing molecular weight is preferable because it facilitates the production of varnishes with lower viscosity.

[0136] Since P-5 to P-9 obtained in each example contained small amounts of residual monomer and solvent, they were redissolved in toluene, and the solutions were added in small amounts to a sufficiently large methanol / acetone mixed solution. The precipitated polymer was stirred, filtered, and dried under vacuum at room temperature for 24 hours to obtain purified polymer. The composition and molecular weight of the obtained P-5 to P-9 are shown in Table 1. The purified polymer was again dissolved in toluene to obtain a 50% by mass toluene solution (varnish). The varnish was applied to a smooth Teflon® plate with an applicator and air-dried at 25°C for more than 3 hours, then dried under vacuum at 120°C for 12 hours, and then dried under vacuum at 200°C for 60 minutes to obtain a transparent sheet with a thickness of 0.1 mm. This sheet was cut into small pieces and the gel content was measured. From the results of this gel content measurement, it was confirmed that the sheet was in an uncured state. The viscoelastic spectrum (DMA) was measured using this sheet, and the storage modulus at 25°C and the glass transition temperature were measured. The dielectric properties were measured using this sheet. These results are shown in Table 1. The copolymer of the present invention exhibits a high glass transition temperature in the uncured state, and shows a high storage modulus (25°C), low dielectric constant, and low dielectric loss tangent. P-5 to P-9 obtained using a boron compound as a co-catalyst show a low dielectric constant and low dielectric loss tangent.

[0137] 13C-NMR analysis of the norbornene-ethylvinylbenzene-divinylbenzene copolymer of P-8 was performed to examine the end structures, and no end structures other than E-1 to E-8 were detected. Furthermore, the end structures characteristic of cationic polymerization described in International Publication No. 2018 / 181842 (structures denoted as t1 and t2 in International Publication No. 2018 / 181842) were not detected in P-8.

Claims

1. An α-olefin-cyclic olefin-aromatic polyene copolymer in its uncured state, having a dielectric constant of less than 2.4 and a dielectric loss tangent of less than 0.0008 at a measurement frequency of 40 GHz, and a storage modulus of 1000 MPa or more measured at 25°C.

2. An α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer in its uncured state, having a dielectric constant of less than 2.4 and a dielectric loss tangent of less than 0.0008 at a measurement frequency of 40 GHz, and a storage modulus of 1000 MPa or more measured at 25°C.

3. The copolymer according to claim 1 or 2, wherein the uncured copolymer has a dielectric constant of less than 2.3 and a dielectric loss tangent of less than 0.0004 at a measurement frequency of 40 GHz.

4. The copolymer according to any one of claims 1 to 3, wherein the total metal content derived from the catalyst and co-catalyst contained in the copolymer is 1000 ppm or less.

5. The copolymer according to any one of claims 1 to 4, wherein, when cured alone, the cured body exhibits a dielectric constant of less than 3.5 and a dielectric loss tangent of less than 0.001 at a measurement frequency of 40 GHz.

6. The copolymer according to claim 5, wherein, when cured alone, the dielectric constant of the cured body at a measurement frequency of 40 GHz is less than 2.3 and the dielectric loss tangent is less than 0.0004.

7. The copolymer according to any one of claims 1 to 6, wherein, when cured alone, the storage modulus of the cured body measured at 280°C is 1 MPa or more.

8. The copolymer according to any one of claims 1 to 7, wherein, when cured alone, the storage modulus of the cured body measured at 280°C is 5 MPa or more.

9. The copolymer according to claim 1, satisfying all of the following (1) to (2), (4) to (6). (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 to 30 carbon atoms, and its content is 30% by mass or more and 99% by mass or less. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl and / or vinylene groups in the molecule, and the content of vinyl and / or vinylene groups derived from the aromatic polyene monomer unit is 2 to 30 per number average molecular weight. (6) The total of α-olefin units, cyclic olefin units, and aromatic polyene units is 100% by mass.

10. The copolymer according to claim 2, satisfying all of the following (1) to (6). (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 or more carbon atoms and 20 or fewer carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 to 30 carbon atoms, and its content is 30% by mass or more and 99% by mass or less. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl and / or vinylene groups in the molecule, and the content of vinyl and / or vinylene groups derived from the aromatic polyene monomer unit is 2 to 30 per number average molecular weight. (6) The total of α-olefin units, cyclic olefin units, aromatic vinyl compound units, and aromatic polyene units is 100% by mass.

11. The copolymer according to any one of claims 1 to 10, wherein the cyclic olefin unit comprises one or more selected from the group consisting of norbornene, methylphenylnorbornene, substituted norbornene other than methylphenylnorbornene, and dimethanooctahydronaphthalene.

12. The copolymer according to any one of claims 1 to 11, wherein the glass transition temperature is in the range of 100°C to 350°C.

13. The copolymer according to any one of claims 1 to 12, wherein the number average molecular weight is 500 or more and less than 30,000.

14. A method for producing a copolymer according to any one of claims 1 to 13, comprising copolymerizing monomers of an α-olefin, a cyclic olefin, and an aromatic polyene, and optionally an aromatic vinyl compound, by coordination polymerization using a coordination polymerization catalyst.

15. The method for producing a copolymer according to claim 14, 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. General formula (1) 【Chemistry 1】 In the formula, A and B are each independently 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 from each other or the same. Also, Y may have a cyclic structure. X is hydrogen, a 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 1 to 4 carbon atoms with a hydrocarbon substituent, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having 1 to 6 carbon atoms with an alkyl substituent. M stands for zirconium, hafnium, or titanium.

16. A method for producing a copolymer according to claim 15, wherein A and B in general formula (1) are each independently selected from an unsubstituted or substituted cyclopentadienyl group or an unsubstituted or substituted indenyl group.

17. The manufacturing method according to claim 15 or 16, wherein a co-catalyst containing a boron compound is used.

18. The manufacturing method according to claim 17, wherein the co-catalyst further comprises an aluminum compound.

19. A cured body comprising the copolymer according to any one of claims 1 to 13.

20. An α-olefin-cyclic olefin-aromatic polyene copolymer that satisfies all of the following conditions (1) to (2) and (4) to (6), (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 to 30 carbon atoms, and its content is 30% by mass or more and 99% by mass or less. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl and / or vinylene groups in the molecule, and the content of vinyl and / or vinylene groups derived from the aromatic polyene monomer unit is 2 to 30 per number average molecular weight. (6) The total of α-olefin units, cyclic olefin units, and aromatic polyene units is 100% by mass. One or more additive components selected from the group consisting of resin components, curing agents, monomers, solvents, and fillers. A cured body of a composition containing, A hardened body exhibiting 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.

21. An α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer that satisfies all of the following (1) to (6), (1) The number-average molecular weight of the copolymer is between 500 and 100,000. (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms. (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 or more carbon atoms and 20 or fewer carbon atoms. (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 to 30 carbon atoms, and its content is 30% by mass or more and 99% by mass or less. (5) The aromatic polyene unit is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl and / or vinylene groups in the molecule, and the content of vinyl and / or vinylene groups derived from the aromatic polyene monomer unit is 2 to 30 per number average molecular weight. (6) The total of α-olefin units, cyclic olefin units, aromatic vinyl compound units, and aromatic polyene units is 100% by mass. One or more additive components selected from the group consisting of resin components, curing agents, monomers, solvents, and fillers. A cured body of a composition containing, A hardened body exhibiting 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.

22. Furthermore, the cured body according to any one of claims 19 to 21, wherein the storage modulus measured at 25°C is 1000 MPa or more, and the storage modulus measured at 280°C is 1 MPa or more.

23. A cured body according to any one of claims 19 to 22, which is an electrical insulating material.

24. A CCL substrate, an FCCL substrate, an interlayer insulating material, a coverlay, a high-frequency transmission circuit, or an antenna, comprising the cured body described in claim 23.

25. A method for producing a cured product, comprising the step of polymerizing a copolymer according to at least one of claims 1 to 13 with a radical polymerization initiator composed only of carbon atoms and hydrogen atoms, and not containing oxygen atoms or nitrogen atoms in its structure.

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