Copolymer, method for producing same, and cured body comprising copolymer

Abstract

Provided is a novel copolymer which exhibits excellent low dielectric properties in an uncured state and exhibits a high elastic modulus at room temperature. The present invention relates to an alpha olefin-cyclic olefin-aromatic polyene copolymer in which the copolymer in an uncured state has a dielectric constant of less than 2.4 at a measurement frequency of 40 GHz, a dielectric loss tangent of less than 0.0008, and a storage elastic modulus measured at 25 DEG C of 1000 MPa or more.

Description

Technical Field

[0001] The present invention relates to a copolymer, a method for producing the same, and a cured product containing the copolymer. Background Art

[0002] As communication frequencies develop towards the gigahertz band and higher bands, the demand for multi-layer substrates formed of CCL and FCCL containing insulating materials with low dielectric properties has increased. Fluorine-based resins such as perfluoroethylene have excellent characteristics of low dielectric constant, low dielectric loss, and excellent heat resistance, but are difficult in terms of molding processability and film formability. In addition, there are also problems in the adhesiveness with wiring copper foil, so it is difficult to apply to multi-layer 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 are widely used because of their heat resistance and ease of operation, but have high dielectric constants and dielectric losses, and improvement is desired as insulating materials for high frequencies (Patent Document 1).

[0003] Therefore, hydrocarbon resins having inherently low dielectric properties have attracted much attention. In particular, cyclic olefin-based (co)polymers having a high glass transition temperature (Tg) have been proposed as this insulating material in the form of a thermoplastic resin (Patent Documents 2 and 3). However, since its glass transition temperature is close to the reflow soldering temperature, a crosslinkable (curable) resin is preferably used in consideration of process compatibility and process window. Originally, in order to convert a hydrocarbon resin as a thermoplastic resin into a curable resin, a crosslinkable functional group needs to be introduced. However, generally, functional groups that react with free radicals or undergo thermal reactions have polarity, so the low dielectric properties deteriorate. When attempting to introduce a functional group composed only of hydrocarbons, such as aromatic vinyl, it often involves intermolecular reactions between expensive hydrocarbon raw materials (Patent Document 4), and is uneconomical in many cases. Patent Document 5 discloses a cured body obtained from a specific coordination polymerization catalyst and containing an ethylene-olefin (aromatic vinyl compound)-aromatic polyene copolymer having a specific composition and coordination. In the case of the technology of Patent Document 5, only one of the two vinyl groups of aromatic polyene (divinylbenzene) is selectively copolymerized and the remaining vinyl group is retained, so that a crosslinkable hydrocarbon copolymer macromonomer having a functional group of aromatic vinyl can be easily obtained. Cured bodies obtained from the same olefin-aromatic vinyl compound-aromatic polyene copolymer and its compositions with auxiliary raw materials and the like have characteristics such as a low dielectric constant and a low dissipation factor, and can provide a wide range of physical properties from soft to hard through the selection of composition and appropriate auxiliary raw materials (Patent Documents 6 and 7). However, the specifically described olefin-aromatic vinyl compound-aromatic polyene copolymer is relatively soft, and in order to harden it, a large amount of other crosslinkable hard resins and inorganic fillers need to be compounded. Here, known crosslinkable hard resins have the following problems: their low dielectric properties are insufficient, and if a large amount is compounded, the low dielectric properties of the cured body decrease. If a large amount of inorganic fillers is compounded, since the dielectric constant of inorganic fillers is generally high, the dielectric constant of the obtained cured body, especially, becomes high. In a cured body, in addition to being hard, it is important to simultaneously exhibit a high glass transition temperature (Tg), so that a low linear expansion rate (CTE) can be exhibited within the processing temperature range of the manufacturing process of electronic circuit components including the reflow soldering process. Therefore, a hard resin with a higher glass transition temperature is required. Furthermore, the insulating material used in a substrate or the like is produced by mixing and curing with various raw materials such as resins, fillers, and flame retardants, and high compatibility with these raw materials is also required. In particular, resins and flame retardants contain many aromatic groups in order to obtain stability and flame retardancy at high temperatures, so a crosslinkable hard material with high compatibility with them is required. In summary, a material having crosslinkability, excellent low dielectric properties of its cured product, a high glass transition temperature, and a high elastic modulus at room temperature and high temperature is required.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 6-192392

[0007] Patent Document 2: International Publication No. 1998 / 56011

[0008] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2016-037045

[0009] Patent Document 4: Japanese Unexamined Patent Application Publication No. 2004-087639

[0010] Patent Document 5: Japanese Unexamined Patent Application Publication No. 2007-217706

[0011] Patent Document 6: International Publication No. 2021 / 112087

[0012] Patent Document 7: International Publication No. 2021 / 112088 Summary of the Invention

[0013] Problems to be Solved by the Invention

[0014] However, there is no description in the above prior art that an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer has low dielectric properties, a high glass transition temperature, and a high elastic modulus at a sufficient level in an uncured state.

[0015] Means for Solving the Problems

[0016] In view of the above problems, an object of the present invention is to provide a novel crosslinkable copolymer (polymer compound) and a cured product thereof, which are an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer having low dielectric properties, a high glass transition temperature, and a high elastic modulus at room temperature and high temperature even in an uncured state.

[0017] That is, the present invention can provide the following embodiments.

[0018] Embodiment 1.

[0019] An α-olefin-cyclic olefin-aromatic polyene copolymer, wherein the copolymer in an uncured state has a dielectric constant of less than 2.4 at a measurement frequency of 40 GHz, a dielectric loss tangent of less than 0.0008, and a storage elastic modulus measured at 25°C of 1000 MPa or more.

[0020] Embodiment 2.

[0021] α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, wherein the copolymer in the uncured state has 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 elastic modulus measured at 25°C of 1000 MPa or more.

[0022] Mode 3.

[0023] The copolymer according to Mode 1 or 2, wherein the copolymer in the uncured state 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.

[0024] Mode 4.

[0025] The copolymer according to any one of Modes 1 to 3, wherein the total content of metals derived from the catalyst and the cocatalyst contained in the copolymer is 1000 ppm or less.

[0026] Mode 5.

[0027] The copolymer according to any one of Modes 1 to 4, wherein when cured alone, the cured body 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.

[0028] Mode 6.

[0029] The copolymer according to any one of Modes 1 to 5, wherein when cured alone, the cured body 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.

[0030] Mode 7.

[0031] The copolymer according to any one of Modes 1 to 6, wherein when cured alone, the cured body has a storage elastic modulus measured at 280°C of 1 MPa or more.

[0032] Mode 8.

[0033] The copolymer according to any one of Modes 1 to 7, wherein when cured alone, the cured body has a storage elastic modulus measured at 280°C of 5 MPa or more.

[0034] Mode 9.

[0035] The copolymer according to any one of Modes 1 to 8, which satisfies all of the following (1) to (2), (4) to (6).

[0036] (1) The number average molecular weight of the copolymer is 500 or more and 100,000 or less.

[0037] (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms.

[0038] (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 or more and 30 or less carbon atoms, and its content is 30% by mass or more and 99% by mass or less.

[0039] (5) The aromatic polyene unit is one or more selected from polyenes having 5 or more and 20 or less 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.

[0040] (6) The total of the α-olefin unit, the cyclic olefin unit, and the aromatic polyene unit is 100% by mass.

[0041] Mode 10.

[0042] The copolymer according to Mode 2, which satisfies all of the following (1) to (6).

[0043] (1) The number average molecular weight of the copolymer is 500 or more and 100,000 or less.

[0044] (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms.

[0045] (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 or more and 20 or less carbon atoms.

[0046] (4) The cyclic olefin unit is a cyclic olefin monomer unit having 10 or more and 30 or less carbon atoms, and its content is 30% by mass or more and 99% by mass or less.

[0047] (5) The aromatic polyene unit is one or more selected from polyenes having 5 or more and 20 or less 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.

[0048] (6) The total of the α-olefin unit, the cyclic olefin unit, the aromatic vinyl compound unit, and the aromatic polyene unit is 100% by mass.

[0049] Mode 11.

[0050] The copolymer according to any one of Modes 1 to 10, wherein the cyclic olefin unit contains one or more selected from the group consisting of norbornene, methylphenylnorbornene, substituted norbornene other than methylphenylnorbornene, and dimethanooctahydronaphthalene.

[0051] Mode 12.

[0052] The copolymer according to any one of Modes 1 to 11, having a glass transition temperature in the range of 100°C or higher and 350°C or lower.

[0053] Mode 13.

[0054] The copolymer according to any one of Modes 1 to 12, having a number average molecular weight of 500 or more and less than 30,000.

[0055] Mode 14.

[0056] The method for producing a copolymer according to any one of Modes 1 to 13, wherein each monomer of an α-olefin, a cyclic olefin, an aromatic polyene, and, if necessary, an aromatic vinyl compound is copolymerized by coordination polymerization using a coordination polymerization catalyst.

[0057] Mode 15.

[0058] The method for producing a copolymer according to Mode 14, wherein the coordination polymerization catalyst is a polymerization catalyst comprising a transition metal compound represented by the following general formula (1) and a cocatalyst.

[0059] General formula (1)

[0060] [Chemical formula 1]

[0061]

[0062] In the formula, A and B are each independently a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzoindenyl group, an unsubstituted or substituted cyclopentadienyl group, or an unsubstituted or substituted indenyl group.

[0063] Y is a methylene group, a silylene group, an ethylene group, a germylene group, or a boron residue having a bond with A and B and having a hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as a substituent. The substituents may be different or the same as each other. In addition, Y may have a cyclic structure.

[0064] 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 a hydrocarbon substituent having 1 to 4 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having an alkyl substituent having 1 to 6 carbon atoms.

[0065] M is zirconium, hafnium, or titanium.

[0066] Mode 16.

[0067] The method for producing a copolymer as described in Mode 15, wherein A and B in the general formula (1) are each independently a group selected from unsubstituted or substituted cyclopentadienyl groups or unsubstituted or substituted indenyl groups.

[0068] Mode 17.

[0069] The production method as described in Mode 15 or 16, wherein a cocatalyst containing a boron compound is used.

[0070] Mode 18.

[0071] The production method as described in Mode 17, wherein the aforementioned cocatalyst further contains an aluminum compound.

[0072] Mode 19.

[0073] A cured product containing the copolymer described in any one of Modes 1 to 13.

[0074] Mode 20.

[0075] A cured product which is a cured product of the following composition, the composition containing: an α-olefin-cyclic olefin-aromatic polyene copolymer satisfying all of the following (1) to (2), (4) to (6); and one or more additive components selected from the group consisting of a resin component, a curing agent, a monomer, a solvent, and a filler.

[0076] (1) The number-average molecular weight of the copolymer is 500 or more and 100,000 or less.

[0077] (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms.

[0078] (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.

[0079] (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 unit number-average molecular weight.

[0080] (6) The total of the α-olefin unit, the cyclic olefin unit, and the aromatic polyene unit is 100% by mass.

[0081] The cured product has 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.

[0082] Mode 21.

[0083] A solidified body, which is a solidified body of the following composition, the composition comprising: an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following (1) to (6); and one or more additive components selected from the group consisting of a resin component, a curing agent, a monomer, a solvent, and a filler,

[0084] (1) The number average molecular weight of the copolymer is 500 or more and 100,000 or less.

[0085] (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms.

[0086] (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 to 20 carbon atoms.

[0087] (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.

[0088] (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 unit number average molecular weight.

[0089] (6) The total of the α-olefin unit, the cyclic olefin unit, the aromatic vinyl compound unit, and the aromatic polyene unit is 100% by mass.

[0090] The solidified body has 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.

[0091] Aspect 22.

[0092] The solidified body according to any one of Aspects 19 to 21, and the storage elastic modulus measured at 25 °C is 1000 MPa or more, and the storage elastic modulus measured at 280 °C is 1 MPa or more.

[0093] Aspect 23.

[0094] The solidified body according to any one of Aspects 19 to 22, which is an electrical insulating material.

[0095] Aspect 24.

[0096] A CCL substrate, an FCCL substrate, an interlayer insulating material, a cover layer, a high-frequency transmission circuit, or an antenna, which comprises the solidified body according to Aspect 23.

[0097] Aspect 25.

[0098] A method for producing a solidified body, which at least includes the following steps: polymerizing the copolymer described in any one of Modes 1 to 13 by using a radical polymerization initiator whose structure contains no oxygen atoms or nitrogen atoms and is composed only of carbon atoms and hydrogen atoms.

[0099] Effects of the Invention

[0100] The copolymer of the present invention has excellent low dielectric properties even in an uncured state, shows a high elastic modulus at room temperature, and has curability. In addition, the solidified body of this copolymer also exhibits the following effects: having excellent low dielectric properties and a high glass transition temperature; and having a high elastic modulus at room temperature and high temperature. If the copolymer satisfies the above properties in an uncured state, the cured product containing this copolymer can also satisfy these properties. Detailed Description of Embodiments

[0101] Hereinafter, further detailed description will be given. In this specification, sometimes the α-olefin-cyclic olefin-aromatic polyene copolymer is included in the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer and is collectively referred to by the latter name. In this specification, sometimes the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer is abbreviated as the copolymer of the present invention, or simply abbreviated as the copolymer. Unless otherwise specified, the numerical ranges in this specification include their upper and lower limits. In this specification, the concept of a sheet also includes that of a film. In addition, in this specification, when it is described as a film, it also means the same as a sheet. In addition, in this specification, when it is described as a film, it also includes the concept of a sheet. In this specification, the uncured state is defined as: the proportion of the gel fraction (gel content) of the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer is 20% by mass or less, more strictly 10% by mass or less, and most strictly 5% by mass or less. It should be noted that this gel fraction is a value obtained by measurement in accordance with JIS K6796:1998 or ASTM D2765-84 corresponding to ISO10147:1994 corresponding to this JIS.

[0102] In one embodiment of the present invention, an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer can be provided. The copolymer can be the following substances: in the uncured state, the dielectric constant at a measurement frequency of 40 GHz is 2.0 or more and less than 2.4, preferably less than 2.3, and the dielectric loss tangent is 0.0001 or more and less than 0.0008, preferably less than 0.0004, more preferably less than 0.0003. In addition, the storage elastic modulus measured at 25 °C is 1000 MPa or more. When the copolymer is cured alone, the dielectric constant of the cured body at a measurement frequency of 40 GHz can be less than 3.5, and the dielectric loss tangent can be less than 0.0010. Preferably, the dielectric constant is 2.0 or more and less than 3.5, and the dielectric loss tangent is 0.0001 or more and less than 0.0010. More preferably, the dielectric constant is 2.0 or more and less than 2.4, and the dielectric loss tangent is less than 0.0004. Most preferably, the dielectric constant is less than 2.3, and the dielectric loss tangent is 0.0001 or more and less than 0.0003. In addition, the storage elastic modulus measured at 25 °C can be 1000 MPa or more. Further, the storage elastic modulus of the cured body measured at 280 °C is preferably 1 MPa or more, more preferably 5 MPa or more.

[0103] In addition, in another embodiment, the following method can also be provided: Although the dielectric constant or the dielectric loss tangent in the uncured state does not satisfy the above conditions, the dielectric constant, the dielectric loss tangent, and the storage elastic modulus of the cured body satisfy the above conditions.

[0104] <α-olefin-cyclic olefin-aromatic polyene copolymer>

[0105] In addition, 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 its production method is arbitrary. Preferably, the α-olefin-cyclic olefin-aromatic polyene copolymer is a copolymer that satisfies all of the following (1) to (2), (4) to (6).

[0106] (1) The number average molecular weight of the copolymer is 500 or more and 100,000 or less.

[0107] (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms.

[0108] (4) The cyclic olefin unit is a cyclic olefin monomer having 10 to 30 carbon atoms that may have an aromatic ring, and its content is 30% by mass or more and 99% by mass or less.

[0109] (5) The aromatic polyene unit is one or more selected from polyenes having 5 or more and 20 or less carbon atoms with multiple vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups from the aromatic polyene monomer unit is 2 or more and 30 or less, or 2 or more and less than 30 per unit number average molecular weight.

[0110] (6) The total of the monomer units of α-olefin, cyclic olefin, and aromatic polyene is 100% by mass.

[0111] This α-olefin-cyclic olefin-aromatic polyene copolymer is obtained by copolymerizing each monomer of α-olefin, cyclic olefin, and aromatic polyene.

[0112] <α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer>

[0113] 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.

[0114] In this specification, the α-olefin-cyclic olefin-aromatic polyene copolymer may sometimes be included in the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer and be collectively referred to by the latter name.

[0115] In addition, 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 its production method 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).

[0116] (1) The number average molecular weight of the copolymer is 500 or more and 100,000 or less.

[0117] (2) The α-olefin unit is an α-olefin having 2 to 20 carbon atoms.

[0118] (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 to 20 carbon atoms.

[0119] (4) The cyclic olefin unit is a cyclic olefin monomer having 10 to 30 carbon atoms that may have an aromatic ring, and its content is 30% by mass or more and 99% by mass or less.

[0120] (5) The aromatic polyene unit is one or more selected from polyenes having 5 or more and 20 or less carbon atoms with multiple vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups from the aromatic polyene monomer unit is 2 or more and 30 or less, or 2 or more and less than 30 per unit number average molecular weight.

[0121] (6) The sum of the monomer units of α-olefin, cyclic olefin, aromatic vinyl compound, and aromatic polyene is 100% by mass.

[0122] This α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer is obtained by copolymerizing each monomer of α-olefin, cyclic olefin, aromatic vinyl compound, and aromatic polyene.

[0123] As the α-olefin monomer, it is an α-olefin having 2 or more and 20 or less carbon atoms. For example, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, 3,5,5-trimethyl-1-hexene can be exemplified, and ethylene is most preferred. In this copolymer, the content of α-olefin is arbitrary, preferably 0% by mass or more and 40% by mass or less, more preferably more than 0% by mass and 30% by mass or less, further preferably 1% by mass or more and 30% by mass or less, and most preferably 5% by mass or more and 30% by mass or less. When the content of the α-olefin monomer unit is 40% by mass or less, the content of the cyclic olefin unit relatively increases, and the glass transition temperature of the copolymer can be within a preferred range. The more the content of the α-olefin monomer unit (for example, when it is 5% by mass or more), the less brittle the copolymer and its cured product become.

[0124] In this specification, the cyclic olefin monomer refers to a cyclic olefin having 7 or more and 30 or less carbon atoms (preferably 10 or more and 30 or less carbon atoms). The cyclic olefin having 7 or more and 30 or less carbon atoms is a cyclic olefin having one or more alicyclic structures in the molecule and having a polymerizable vinyl group, vinylene group, or vinylidene group. As a preferred cyclic olefin, a cyclic olefin having a hydrocarbon ring structure without a heteroatom is preferred, and a cyclic olefin having an unsaturated hydrocarbon ring is more preferred. Such a cyclic olefin has characteristics of low dielectric constant and high glass transition temperature, and has a remarkable characteristic that it is easier to prepare with inexpensive raw materials and a simple process compared with engineering plastics in the prior art. As such a cyclic olefin, for example, norbornene-based compounds can be exemplified. Norbornene-based compounds refer to monomers selected from norbornene and substituted norbornene. Norbornene can be synthesized, for example, by the Diels-Alder reaction of ethylene and cyclopentadiene. In addition, substituted norbornene refers to substituted norbornene having a polymerizable vinyl group, vinylene group, or vinylidene group in the molecule, and examples thereof include dimethanooctahydronaphthalene (DMON) and trimethanododecahydroanthracene (TMDA). They are also products of the Diels-Alder reaction of norbornene-based compounds and cyclopentadiene. These substituted norbornenes are also specifically described, for example, in International Publication No. 2006 / 118261. In the present invention, a cyclic olefin having more ring structures and a high molecular weight is more preferred, and examples thereof may include dimethanooctahydronaphthalene (DMON) and trimethanododecahydroanthracene (TMDA). When such a cyclic olefin is copolymerized, a copolymer having a higher glass transition temperature (Tg) can be obtained with a lower 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. By increasing the molar% content of the aromatic vinyl compound monomer unit as other monomer units, the aromatic property of the whole copolymer is improved, and the compatibility with other raw materials and resins of the copolymer can be improved, which is preferred. These high molecular weight cyclic olefins can be used alone, or can be used in the form of a mixture with norbornene or the like for copolymerization. In particular, the above-mentioned DMON and TMDA are sometimes obtained in the form of a mixture with norbornene when produced by the Diels-Alder reaction, and by directly using them in the form of a mixture for polymerization, the manufacturing cost can be reduced.In addition, in the present invention, more preferred cyclic olefins are norbornenes having aromatic substituents. For example, phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), which is a Diels-Alder reaction product of cyclopentadiene and styrene, indanyl norbornene (1,4-methano-1,9a,4,4a-tetrahydrofluorene), which is a Diels-Alder reaction product of cyclopentadiene and indene, and methylphenylnorbornene (MPNB, 5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene), which is a Diels-Alder reaction product of cyclopentadiene and α-methylstyrene, etc. can be exemplified. When such norbornenes having aromatic substituents are copolymerized, a higher glass transition temperature (Tg) can be imparted to the copolymer. Furthermore, since they exhibit aromaticity, high compatibility with other aromatic raw materials (crosslinkable soft resins, flame retardants) can be shown. In addition, if methylphenylnorbornene (5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene) is used, as described in Japanese Patent Application Laid-Open No. 2005-239975, the thermal oxidative resistance of the obtained copolymer can be improved, so it is preferred. These norbornenes having aromatic substituents are also specifically described in, for example, Japanese Patent Application Laid-Open No. 11-504669 and Japanese Patent Application Laid-Open No. 2005-239975. The optimal content of the cyclic olefin unit contained in the copolymer varies depending on the type of cyclic olefin. For example, it is 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. From the viewpoint of imparting a certain degree of toughness to the copolymer, the optimal content of the cyclic olefin unit contained in the copolymer can be less than 90% by mass. By having these content ranges, it is easy to achieve a preferred high glass transition temperature of the copolymer. The preferred glass transition temperature of the copolymer is 100°C or more and 350°C or less, more preferably 130°C or more and 300°C or less, and most preferably 180°C or more and 300°C or less. Those skilled in the art can appropriately adjust the type and content of the cyclic olefin used to achieve this preferred glass transition temperature.

[0125] In a preferred embodiment, the cyclic olefin unit 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 may include one or more selected from the group consisting of norbornene, methylphenylnorbornene, and dimethanooctahydronaphthalene.

[0126] The aromatic vinyl compound monomer is an aromatic vinyl compound having 8 or more and 20 or less carbon atoms. Examples thereof include styrene, p-methylstyrene, ethyl vinylbenzene, p-isobutylstyrene, various vinylnaphthalenes, and various vinylanthracenes. The aromatic vinyl compound may also be copolymerized with components contained in the form of impurities of the aromatic polyene used for polymerization and thus be contained in the copolymer. The content of the aromatic vinyl compound monomer unit contained in the copolymer is arbitrary, 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, still more preferably 0% by mass or more and 20% by mass or less, further preferably 0% by mass or more and 10% by mass or less, and even more preferably 0% by mass. The content of the aromatic vinyl compound monomer unit contained in the copolymer may be greater than 0% by mass. The content of the aromatic vinyl compound monomer unit contained in the copolymer may be 30% by mass or less, may be less than 30% by mass, may be 10% by mass or less, may be less than 10%, may be 1% by mass or less, may be less than 1% by mass, and may be less than 0.5% by mass.

[0127] When the content of the aromatic vinyl compound monomer unit is 40% by mass or less, the content of the cyclic olefin unit relatively increases, and the glass transition temperature of the copolymer can be increased. On the other hand, when the content of the aromatic vinyl compound monomer unit is 10% by mass or more, preferably 30% by mass or more, particularly in the case where the cyclic olefin of the copolymer of the present invention does not have an aromatic substituent, the aromaticity of the copolymer can be increased, the affinity with other resin materials, flame retardants, and fillers becomes good, the bleeding of the flame retardant is easily suppressed, and the filler can be highly filled, so it is preferred. As described above, the glass transition temperature and aromaticity of the copolymer can be adjusted by the content of the aromatic vinyl compound in the copolymer.

[0128] As an aromatic polyene monomer, it is a polyene having 5 or more and 20 or less carbon atoms with multiple vinyl groups and / or vinylene groups in its molecule, preferably a polyene having 8 or more and 20 or less carbon atoms. As the aromatic polyene monomer, a polyene having 8 or more and 20 or less carbon atoms with multiple vinyl groups in its molecule is preferred, and further preferably various divinylbenzenes in ortho, meta, and para positions or a mixture thereof, divinylnaphthalene, divinylanthracene, p-2-propenylstyrene, p-3-butenylstyrene, etc., which have an aromatic vinyl structure and are substantially composed of carbon and hydrogen without oxygen, nitrogen, and halogen. In addition, the bifunctional aromatic vinyl compound described in JP-A-2004-087639, such as 1,2-bis(vinylphenyl)ethane (abbreviation: BVPE), can also be used. Among them, various divinylbenzenes in ortho, meta, and para positions or a mixture thereof are preferably used, and a mixture of meta-divinylbenzene and para-divinylbenzene is most preferably used. In this specification, these divinylbenzenes are referred to as divinylbenzene-based compounds. When using divinylbenzene-based compounds as the aromatic polyene, the vinyl groups contained in the divinylbenzene unit have high crosslinking efficiency during the curing process, and the curing becomes easy, so it is preferred.

[0129] The number average molecular weight of this copolymer is preferably 500 or more and 100,000 or less, more preferably 500 or more and 30,000 or less or 500 or more and less than 30,000, still more preferably 500 or more and 15,000 or less or 500 or more and less than 15,000, and further more preferably 500 or more and 12,000 or less or 500 or more and less than 12,000. When the number average molecular weight is 500 or more, the mechanical properties of the composition in the uncured stage become higher, and the adhesiveness becomes moderate, so the effect that the molding process as a thermoplastic resin becomes easy is obtained. 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, when a varnish containing this copolymer is prepared, its viscosity can be made below a certain value, so it is preferred. By making the viscosity of the varnish lower than a certain value, the workability is improved, and it is easy to impregnate the varnish into glass fibers, etc., and the embedding property for semiconductor devices having uneven surfaces is improved.

[0130] In this copolymer, the content of vinyl and / or vinylidene derived from the aromatic polyene unit is 2 or more and 30 or less, preferably 3 or more and 20 or less, per number-average molecular weight unit. The content of vinyl and / or vinylidene derived from the aromatic polyene unit can be less than 30 per number-average molecular weight unit, preferably less than 20. Hereinafter, the content of vinyl and / or vinylidene may sometimes be collectively referred to as the "vinyl content". Considering the crosslinking efficiency, vinyl is more excellent than vinylidene. Therefore, in the present invention, preferably, the content of vinyl (in this case, excluding vinylidene) derived from the aromatic polyene unit is 2 or more and 30 or less, preferably 3 or more and 20 or less, per number-average molecular weight unit. When the vinyl content is 2 or more, the crosslinking efficiency is high, and a cured body with a sufficient crosslinking density can be obtained. When the vinyl content increases, it is easy to improve the mechanical properties of the finally obtained cured body at normal temperature and high temperature. The vinyl content of the aromatic polyene unit (divinylbenzene unit) per number-average molecular weight in the copolymer can be obtained by the following method: comparing the number-average molecular weight (Mn) in terms of standard polystyrene obtained by the GPC (gel permeation chromatography) method known to those skilled in the art with the composition and the vinyl content of the aromatic polyene unit obtained by 1 1H-NMR measurement and / or the 13 13C-NMR measurement. Such a method is obvious and known to those skilled in the art. Alternatively, it can be a certain method described in the patent documents of the prior art literature of this specification. The content of the aromatic polyene monomer unit in this copolymer is arbitrary, preferably less than 40% by mass, more preferably less than 30% by mass. At such a content, the number of crosslinking groups is appropriately suppressed, and the effects of improving the stability during copolymer production and the stability during curing are obtained.

[0131] In this copolymer, as an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, specifically, examples of suitable copolymers include one or more selected from the group consisting of propylene-norbornene-styrene-divinylbenzene copolymer, 1-hexene-norbornene-styrene-divinylbenzene copolymer, 1-octene-norbornene-styrene-divinylbenzene copolymer, ethylene-norbornene-ethyl vinylbenzene-divinylbenzene copolymer, propylene-styrene-norbornene-divinylbenzene copolymer, 1-hexene-styrene-norbornene-divinylbenzene copolymer, and 1-octene-norbornene-styrene-divinylbenzene copolymer. In addition, copolymers obtained by replacing the above norbornene with dimethanooctahydronaphthalene (DMON), trimethanododecahydroanthracene (TMDA), phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), or methylphenylnorbornene (5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene) are also examples of suitable copolymers of the present invention.

[0132] In one embodiment, in the α-olefin-cyclic olefin-aromatic polyene copolymer or α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer, a form in which the content of the α-olefin monomer unit is 0% by mass (that is, the α-olefin monomer unit is not included) may also be provided. In this specification, such a copolymer is also referred to as a "cyclic olefin-aromatic polyene copolymer" or a "cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer". The copolymer according to this form will be described below. Here, regarding the types of each monomer of the cyclic olefin, aromatic vinyl compound, and aromatic polyene, and the content of each monomer unit in the copolymer, as described above.

[0133] The above-mentioned cyclic olefin-aromatic polyene copolymer or cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer can be produced by the production methods described in this specification. Specifically, a coordination polymerization catalyst containing a transition metal compound and a cocatalyst can be used to produce from each monomer of the cyclic olefin, aromatic vinyl compound, and aromatic polyene. The chemical structure of this copolymer obtained by using a coordination polymerization catalyst containing a combination of a transition metal compound and a cocatalyst has the characteristic of not including a specific structure. That is, in the case of a conventional copolymer obtained by the cationic polymerization method related to the prior art, it has a characteristic polymer terminal structure described in, for example, International Publication No. 2018 / 181842, while the copolymer according to the embodiment of the present invention does not have such a structure, and there is a significant difference between the two. Due to this difference, the present invention can achieve the effect of being easy to perform molecular design.

[0134] The polymer terminal structure contained in the cyclic olefin-aromatic polyene copolymer or cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer can be qualitatively or quantitatively clarified by a known method using 1 H-NMR, 13 13C-NMR. As a typical example of this copolymer, the polymer terminal structure contained in the cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer composed of norbornene as the cyclic olefin, DMON, MPNB, styrene or ethyl vinylbenzene as the aromatic vinyl compound, and divinylbenzene as the aromatic polyene is substantially one of the structures represented by the following E-1 to E-8, or any combination thereof. Regarding these structural formulas, in the case of a cyclic olefin other than the foregoing, an aromatic vinyl compound other than the foregoing, and an aromatic polyene other than divinylbenzene, it can be understood by substituting the corresponding structure. The term "substantially" means that 90 mol% or more, preferably 95 mol% or more, and most preferably 99 mol% or more of all the terminal structures of the copolymer are one of the structures represented by the following E-1 to E-8, or any combination thereof.

[0135] [Chemical Formula 2]

[0136]

[0137] In the above formula, P represents the polymer structural residue of a norbornene (or DMNO, or MPNB)-styrene (or ethyl vinylbenzene)-divinylbenzene copolymer. Z represents hydrogen, ethyl, or vinyl.

[0138] In addition, when the cyclic olefin is DMON or MPNB, the structure containing substituents R1 and R2 is as shown below.

[0139] [Chemical Formula 3]

[0140]

[0141] Regarding the polymerization initiation terminal, which accounts for approximately half of the polymer terminal structure, generally, the above E-1, E-2, E-4, and E-5 are more numerous. Since these structures are terminals with saturated structures, the aromatic vinyl compound-aromatic polyene copolymer inherently has the characteristics of high durability such as heat resistance. The structural ratio of the polymerization initiation terminal varies according to various factors. For example, the following factors can be cited: whether the initial monomer insertion occurs with respect to the metal-hydrogen bond; whether the initial monomer insertion occurs with respect to the metal-alkyl structure; whether the initial monomer insertion is caused by any one of the cyclic olefin, styrene, or divinylbenzene; when the initial monomer is styrene or divinylbenzene, whether it is 2,1 insertion or 1,2 insertion; and so on.

[0142] In addition, regarding the structure of the chain transfer terminal (also called the polymerization termination terminal) of the polymer growth chain in the polymer terminal structure, generally, E-1, E-6, and E-8 are more numerous, and E-3, E-4, and E-7 are also included. The ratio of the chain transfer terminal structure varies depending on the following situations: chain transfer occurs due to hydrogen abstraction at the β position; or chain transfer occurs due to chain transfer to other coordinated monomers; or chain transfer occurs due to chain transfer to alkylaluminum as a cocatalyst component; or chain transfer occurs due to chain transfer to a chain transfer agent such as hydrogen. Generally, since the structure of the cyclic olefin is rigid, the E-3 structure generated by hydrogen abstraction at the β position is less.

[0143] In any case, the polymer terminal structure of the above-mentioned cyclic olefin-aromatic polyene copolymer or cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer is composed of one or more of the structures of E-1 to E-8 above, and substantially does not contain other structures. The aromatic vinyl compound-aromatic polyene copolymer containing olefins according to the present invention is obtained by specific coordination polymerization, and thus is a copolymer with a low degree of polymer chain branching and a high linearity, and the proportion of the polymer terminal structure contained therein is also small.

[0144] An example of a polymer obtained by cationic polymerization in the prior art will be compared with the present invention. The characteristic terminal structure (structures denoted as t1 and t2 in International Publication No. 2018 / 181842) formed by chain transfer such as electrophilic substitution reaction of the carbocation at the polymer growth terminal with an aromatic monomer or the aromatic ring contained in the polymer itself is not included in the copolymer according to the present invention. On the other hand, in the aromatic vinyl compound-aromatic polyene copolymer of the prior art described in International Publication No. 2018 / 181842, since it has a dendritic and multi-branched structure, each polymer molecule contains a very large number of terminal structures, and almost all of the terminal structures described therein are vinyl and vinylene unsaturated structures derived from various structures of cationic polymerization. Therefore, there are problems in terms of heat resistance stability. In particular, a large amount of vinylene remains in the cured body even after the curing reaction, and thus the problem of deteriorating heat resistance stability after curing cannot be solved. That is, if a large amount of unsaturated groups such as vinylene are present in the cured body, they will combine and react with oxygen in the air. As a result, the values of the dielectric constant and the dielectric loss tangent of the cured body will increase, which is not preferable.

[0145] In addition, Japanese Patent Application Laid-Open No. 2018-39995 also describes a cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer of the prior art obtained by the same cationic polymerization. Although there is no description of the terminal structure in this patent document, since the same production method as that of International Publication No. 2018 / 181842 is adopted, more than half of the resulting polymer is formed of aromatic polyene and aromatic vinyl compound units, contains a high content of aromatic polyene (divinylbenzene) units, and has a similarly large molecular weight distribution (Mw / Mn). Therefore, it is considered to have the same terminal structure as the terminal structure described in International Publication No. 2018 / 181842 and have a dendritic multi-branched structure. It is considered that a cyclic olefin structure is present in a part of its terminal structure, so the proportion of the aforementioned terminal unsaturated groups can be reduced, and the increase ratios of the dielectric constant and the loss tangent after the heat resistance test are also reduced compared with the case where no cyclic olefin is contained, but it is still insufficient. Compared with the dendritic structure with many terminal groups related to such prior art, the copolymer of the present invention has a more linear structure, the number of terminal structures in one molecule of the copolymer is also small, and there is no case where cyclic olefins are segregated at the terminals of the copolymer. Therefore, the number of cyclic olefin terminals contained in one molecule of the copolymer is usually less than 1.5.

[0146] If the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer of the present invention is cured alone, it can be sufficiently cured. Here, the so-called "cured alone" means that a curing agent (peroxide or other free radical polymerization initiator) is added in an amount of 1 part by mass or less relative to 100 parts by mass of the copolymer, and the curing treatment is carried out under curing conditions appropriate for the peroxide used. The degree of curing can be evaluated by the gel fraction, and the gel fraction is higher than 50%, preferably 90% or more, and particularly preferably 95% or more. The cured product can obtain a cured body that exhibits excellent low dielectric properties, has a high glass transition temperature, and has a high elastic modulus at room temperature and high temperature. 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 further preferably 2.0 or more and less than 2.5. In addition, the tangent of the dielectric loss angle 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 can be arbitrary, and can show 100 °C or more and 350 °C or less, preferably 130 °C or more and 300 °C or less. The storage elastic modulus measured at 25 °C can show 1000 MPa or more, and the storage elastic modulus measured at 280 °C can show 1 MPa or more, more preferably 5 MPa or more. Here, the gel fraction is a value obtained in accordance with the above-mentioned JIS K6796:1998 (or ASTM D2765-84 corresponding to ISO10147:1994 corresponding to this JIS), and the dielectric constant and the tangent of the dielectric loss angle are values obtained under the conditions of 25 °C and 40 GHz. The glass transition temperature and the storage elastic modulus at each temperature are obtained by dynamic viscoelasticity measurement method (DMA) measured at a measurement frequency of 1 Hz. Therefore, for the cured body obtained by curing the composition containing the copolymer, a cured product with a sufficiently high gel fraction can also be obtained, and the cured body can exhibit excellent low dielectric properties, a high glass transition temperature, and a high storage elastic modulus at room temperature and high temperature.

[0147] <Composition containing the copolymer of the present invention>

[0148] The copolymer of the present invention can be cured alone, the copolymer of the present invention can be combined with other materials to form a composition, or the composition can be cured. Here, the so-called "other materials" can include the following "resin component", "curing agent", "monomer", "other olefin-aromatic vinyl compound-aromatic polyene copolymer without cyclic olefin", "solvent", "filler", "other additives", etc.

[0149] <Resin component>

[0150] As the resin component, any resin can be used as long as the effects brought about by the present invention are not impaired. Preferably, one or more selected from hydrocarbon-based elastomers, polyether-based resins, aromatic polyene-based resins, and olefin-aromatic vinyl compound-aromatic polyene copolymers without cyclic olefins can be used. Among them, hydrocarbon-based elastomers and olefin-aromatic vinyl compound-aromatic polyene copolymers without cyclic olefins are further preferred. Among the hydrocarbon-based elastomers, conjugated diene-based polymers are preferred. Among the conjugated diene-based polymers, 1,2-polybutadiene is preferred. With respect to 100 parts by mass of the copolymer of the present invention, the amount of the resin component is preferably in the range of 1 to 500 parts by mass in total, and more preferably in the range of 1 to 300 parts by mass in total.

[0151] <Hydrocarbon-based elastomer>

[0152] The number average molecular weight of the hydrocarbon-based elastomer that can be preferably used in the composition of the present invention can be 20,000 or more, preferably 30,000 or more. Examples of the hydrocarbon-based elastomer include one or more elastomers selected from ethylene-based or propylene-based elastomers, conjugated diene-based polymers, aromatic vinyl compound-conjugated diene-based block copolymers or random copolymers, and their hydrides (hydrogenated products). Examples of the ethylene-based elastomer include ethylene-octene copolymers, ethylene-α-olefin copolymers such as ethylene-1-hexene copolymers, EPR, and EPDM. Examples of the propylene-based elastomer include atactic polypropylene, polypropylene with low stereoregularity, and propylene-α-olefin copolymers such as propylene-1-butene copolymers. These hydrocarbon-based elastomers can be modified by introducing functional groups with maleic anhydride or other compounds.

[0153] <Conjugated diene-based polymer>

[0154] As the conjugated diene polymer, polybutadiene, 1,2-polybutadiene can be mentioned. As the block copolymer or random copolymer of aromatic vinyl compound-conjugated diene system, and their hydrides (hydrogenated products), SBS, SIS, SEBS, SEPS, SEEPS, SEEBS, etc. can be exemplified. The 1,2-polybutadiene that can be preferably used can be obtained, for example, as a product of JSR Corporation. In addition, it can also be obtained from Nippon Soda Co., Ltd. under the product names of liquid polybutadiene: B-1000, 2000, 3000. Further, as the copolymer containing the 1,2-polybutadiene structure that can be preferably used, "Ricon100" of TOTAL CRAYVALLEY Company can be exemplified. These conjugated diene polymers and their hydrides can be modified by introducing functional groups, etc. with maleic anhydride and other compounds. Among the conjugated diene polymers, conjugated diene copolymers are preferred. Among these conjugated diene copolymers, the hydrides of block copolymers such as SEBS, SEPS, SEEPS, SEEBS are useful as the solubilizer of the copolymer of the present invention and other <resin components>. These can be obtained from Asahi Kasei under the trade name Tuftec or SOE-SS, from Kuraray Co., Ltd. under the trade name SEPTON, and from KRATON Corporation under the trade name KRATON.

[0155] <Polyether resin>

[0156] As polyether resins, polyphenylene ether and polyether can be mentioned. As polyphenylene ether having a functional group, it is preferably modified with a functional group at the molecular end. In addition, when added for the purpose of curing the composition of the present invention, it preferably has a plurality of functional groups in one molecule. For example, modified polyphenylene ether is preferred. As the functional group, a radically polymerizable functional group, an epoxy group and the like can be mentioned, and a radically polymerizable functional group is preferred. As the radically polymerizable functional group, vinyl is preferred. As vinyl, one or more selected from the group consisting of allyl, (meth)acryloyl, and aromatic vinyl are preferred, more preferably one or more selected from the group consisting of (meth)acryloyl and aromatic vinyl, and most preferably aromatic vinyl. That is, in the composition of the present invention, a bifunctional polyphenylene ether in which both ends of the molecular chain are modified with a radically polymerizable functional group is particularly preferred. As such polyphenylene ether, Noryl (trademark) SA9000 of SABIC (a modified polyphenylene ether having methacryloyl groups at both ends, number average molecular weight: 2200), bifunctional polyphenylene ether oligomer (OPE-2St) manufactured by Mitsubishi Gas Chemical Company (a modified polyphenylene ether having vinylbenzyl groups at both ends, number average molecular weight: 1200), etc. can be mentioned. In addition, allylated PPE of Asahi Kasei Corporation, aromatic polyether (ELPAC HC-F series) of JSR Corporation can also be used. Among these, it is preferable to be able to use the bifunctional polyphenylene ether oligomer (OPE-2St) manufactured by Mitsubishi Gas Chemical Company and the aromatic polyether (ELPAC HC-F series) of JSR Corporation.

[0157] <Aromatic polyene resin>

[0158] The so-called aromatic polyene resin includes a divinylbenzene-based reactive multi-branched copolymer (PDV or ODV) manufactured by NIPPON STEEL Chemical & Material Co., Ltd. Such a copolymer is described, for example, in the literature "Synthesis of multifunctional aromatic vinyl copolymers and development of novel IPN-type low dielectric loss materials using the same" (Masanao Kawabe et al., Journal of the Institute of Electronics Packaging, p125, Vol. 12 No. 2 (2009)).

[0159] <Other olefin - aromatic vinyl compound - aromatic polyene copolymer without cyclic olefin>

[0160] The other olefin - aromatic vinyl compound - aromatic polyene copolymer without cyclic olefin that can be used in the present invention is an olefin - aromatic vinyl compound - aromatic polyene copolymer that satisfies all of the following (A) to (E).

[0161] (A) The number average molecular weight of the copolymer is 500 or more and 100,000 or less.

[0162] (B) The olefin monomer unit is one or more selected from α-olefins having 2 or more and 20 or less carbon atoms, and this olefin does not contain cyclic olefins.

[0163] (C) The aromatic vinyl compound monomer unit is an aromatic vinyl compound having 8 or more and 20 or less carbon atoms, and the content of the aromatic vinyl compound monomer unit is 0 or more and 90 mass% or less.

[0164] (D) The aromatic polyene monomer unit is one or more selected from polyenes having 5 or more and 20 or less carbon atoms having a plurality of vinyl groups and / or vinylene groups in the molecule, and the content of the vinyl group and / or vinylene group derived from the aromatic polyene unit is 2 or more and 30 or less per number average molecular weight. The content of the vinyl group and / or vinylene group derived from the aromatic polyene unit per number average molecular weight may be 2 or more and less than 30.

[0165] (E) The total of the olefin monomer unit, the aromatic vinyl compound monomer unit, and the aromatic polyene monomer unit is 100 mass%.

[0166] The details of each monomer of the α-olefin, the aromatic vinyl compound, and the aromatic polyene are as described above. Such copolymers are specifically described in Japanese Patent Application Laid-Open No. 2009-161743, International Publication No. 2021 / 112087, International Publication No. 2021 / 112088, and International Publication No. 2022 / 014599. However, as described above, such other copolymers do not contain cyclic olefins. Among the olefin-aromatic vinyl compound-aromatic polyene copolymers that do not contain cyclic olefins, in particular, copolymers in which the content of the aromatic vinyl compound monomer is 0 or more and 60 mass% or less are soft, and thus, by blending them into the copolymer of the present invention, the toughness of the obtained cured product can be improved and fracture can be suppressed, and thus they are preferred.

[0167] <Curing agent>

[0168] As the curing agent that can be contained in the present composition, known curing agents that have been conventionally used in the polymerization or curing of aromatic polyenes and aromatic vinyl compounds can be used. Such curing agents can be exemplified by radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators, and radical polymerization initiators are preferably used. Preferred are organic peroxide-based (peroxides), azo-based polymerization initiators, etc., which can be freely selected according to the use and conditions. The catalog listing organic peroxides can be downloaded from the homepage of NOF Corporation, such as https: / / www.nof.co.jp / product-search / family / 1020001. In addition, organic peroxides are also described in the catalogs of Fujifilm Wako Pure Chemical Corporation, Tokyo Chemical Industry Co., Ltd., etc. The curing agent used in the present invention can be obtained from these companies. In addition, a hydrocarbon-based radical polymerization initiator that does not contain an oxygen atom or a nitrogen atom in its structure, that is, a radical polymerization initiator composed only of carbon atoms and hydrogen atoms, such as 2,3-dimethyl-2,3-diphenylbutane, can also be preferably used. When a cured body is manufactured using such a hydrocarbon-based radical polymerization initiator, a cured body having a low dielectric constant and a low dielectric loss tangent that does not contain an oxygen atom or a nitrogen atom can be obtained, and the effect of further improving the low dielectric properties of the cured body can be obtained. In addition, known photoinitiators using light, ultraviolet rays, or radiation can also be used as the curing agent. As the curing agent using a photoinitiator, a photo radical polymerization initiator, a photo cationic polymerization initiator, or a photo anionic polymerization initiator can be cited. Such photoinitiators can be obtained, for example, from Tokyo Chemical Industry Co., Ltd. In addition, curing can also be carried out using radiation or an electron beam itself. In addition, crosslinking and curing can be carried out by thermal polymerization of the contained raw materials without using a curing agent.

[0169] The amount of the curing agent used is not particularly limited. Generally, relative to 100 parts by mass of the composition (preferably excluding the curing agent and the solvent), the external ratio is preferably 0.01 to 10 parts by mass. In the case of using a curing agent such as a peroxide-based (peroxide) or azo-based polymerization initiator, curing treatment is carried out at an appropriate temperature and time in consideration of its half-life. The conditions in this case can be arbitrarily determined according to the curing agent. Generally, a temperature range of about 50°C to 180°C is appropriate.

[0170] <Monomer>

[0171] The amount of monomers that the composition of the present invention may contain is arbitrary, and is preferably 300 parts by mass or less relative to 100 parts by mass of the copolymer. It should be noted that the present composition may substantially not contain monomers. When monomers are contained, it is preferably 1 part by mass or more, and more preferably 5 parts by mass or more. In particular, when the amount of monomers is 30 parts by mass or less, the uncured composition is less likely to exhibit a viscous property, and the molding process of the thermoplastic resin becomes easier. In addition, if the content of the volatile monomer is below a certain value, the odor will not be a problem at the uncured stage. When a solvent is added to the composition to make the product form a varnish-like state, during use, as the solvent evaporates, the monomers will be lost, and there is a problem that the substantial content of the monomers is likely to decrease. In addition, when the product form is an uncured sheet, if it contains monomers below a certain amount, the change in the monomer content is less likely to occur during storage. The molecular weight of the monomers preferably used in the composition of the present invention is preferably less than 1000, and more preferably less than 500. The monomers preferably used in the composition of the present invention are the aforementioned aromatic vinyl compound monomers, the aforementioned aromatic polyene monomers, the following aromatic vinylidene monomers, and / or the following polar monomers. As such monomers, monomers capable of being polymerized by a radical polymerization initiator are preferred, and more preferably one or more selected from the group consisting of aromatic vinyl compounds and aromatic polyenes. In addition, BVPE (1,2-bis(vinylphenyl)ethane) described in JP-A-2003-212941 can also be preferably used.

[0172] <Aromatic vinylidene monomers>

[0173] The aromatic vinylidene monomers that can be included in the present invention refer to compounds having a single aromatic ring or a plurality of fused aromatic rings with 9 to 30 carbon atoms and a vinylidene group. As such aromatic vinylidene compounds, indene-based compounds, β-substituted styrene-based compounds, acenaphthylene-based compounds, etc. can be cited. As indene-based compounds, indene, various alkyl-substituted indenes, phenyl-substituted indenes, etc. can be cited. As β-substituted styrene-based compounds, β-alkyl-substituted styrenes such as β-methylstyrene, or phenyl-substituted styrenes, etc. can be cited. As acenaphthylene-based compounds, acenaphthylene, various alkyl-substituted acenaphthylenes, various phenyl-substituted acenaphthylenes, etc. can be cited. As the aromatic vinylidene compounds, the aforementioned exemplified compounds can be used alone, or two or more thereof can be used in combination. From the viewpoints of industrial availability and radical polymerizability, as the aromatic vinylidene compound, acenaphthylene is most preferred.

[0174] <Polar monomers>

[0175] For the purpose of imparting adhesiveness to other materials required as an insulating material, a smaller amount of polar monomers can be used. Examples of the above polar monomers include various maleimides, bismaleimides, maleic anhydride, glycidyl (meth)acrylate, triallyl isocyanurate, tris(isocyanuric acid)tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc. The maleimides and bismaleimides that can be used in the present invention are described, for example, in International Publication No. 2016 / 114287 and can be purchased from Daiwa Kasei Co., Ltd. From the viewpoints of solubility in organic solvents, high-frequency characteristics, high adhesiveness to conductors, formability of prepregs, etc., these maleimide group-containing compounds can be used as polyamino bismaleimide compounds. The polyamino bismaleimide compounds can be obtained, for example, by subjecting a compound having two maleimide groups at the terminals to a Michael addition reaction with an aromatic diamine compound having two primary amino groups in the molecule. When high crosslinking efficiency is desired with a small addition amount, it is preferable to use a polyfunctional polar monomer having two or more functional groups, and examples thereof include bismaleimides, triallyl isocyanurate (TAIC), and trimethylolpropane tri(meth)acrylate. The amount of the polar monomer that the composition can contain can be in the range of 0.1 to 30 parts by mass, preferably in the range of 0.1 to 10 parts by mass, relative to 100 parts by mass of the copolymer. By using 30 parts by mass or less, the dielectric constant and the dissipation factor of the obtained cured body are reduced. For example, in a preferred embodiment, the dielectric constant of the cured body of the copolymer can be suppressed to 3.5 or less, and the dissipation factor can be suppressed to 1.2×10 -3 or less.

[0176] <Solvent>

[0177] For the composition of the present invention, an appropriate solvent can be added as needed. The solvent is used to adjust the viscosity and fluidity of the composition. As the solvent, a volatile solvent is preferred. For example, cyclohexane, toluene, ethylbenzene, acetone, isopropyl alcohol, etc. can be used. The solvent is used to adjust the viscosity and fluidity of the composition when it is made into a varnish. When the boiling point at atmospheric pressure is high, that is, when the volatility is low, the thickness of the coated film becomes uniform. Therefore, a solvent having a boiling point of a certain degree or more is preferred. The preferred boiling point is 100 °C or more at atmospheric pressure, more preferably 130 °C or more and 300 °C or less. As the solvent suitable for such a varnish, cyclohexane, toluene, xylene, mesitylene, tetralin, acetone, ethylbenzene, limonene, mixed alkanes, mixed aromatic solvents, ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether, etc. can be used. In addition, in the case of a solvent, particularly the amount used is preferably in the range of 10 to 2000 parts by mass, more preferably 5 to 500 parts by mass, and further preferably 10 to 300 parts by mass with respect to 100 parts by mass of the composition of the present invention. It is preferred to remove the solvent in advance by drying treatment or the like before curing the present composition.

[0178] <Filler>

[0179] An inorganic or organic filler can be added as needed. These fillers are added for the purpose of controlling the thermal expansion rate, controlling the thermal conductivity, reducing the cost, etc., and the added amount is an arbitrary amount depending on the purpose. The composition of the present invention can particularly contain a large amount of inorganic fillers, and the maximum amount that can be added is up to 2000 parts by mass with respect to 100 parts by mass of the copolymer. In particular, when adding an inorganic filler, a known surface modifier, such as a silane coupling agent, etc. is preferably used. In particular, when the composition excellent in low dielectric constant and low dielectric loss is one of the purposes of the present invention, as the inorganic filler, boron nitride (BN) is preferred. From the viewpoint of low dielectric properties, if a large amount is added and compounded, the dielectric constant particularly becomes high. Therefore, it is preferred to use less than 500 parts by mass of the filler, and further preferably less than 400 parts by mass of the filler with respect to 100 parts by mass of the copolymer. Furthermore, in order to improve and enhance the low dielectric properties (low dielectric constant, low dielectric loss tangent), a hollow filler or a filler having a shape with many voids can be added.

[0180] Alternatively, organic fillers such as high molecular weight polyethylene, ultra-high molecular weight polyethylene, polystyrene, styrene-divinylbenzene copolymer, or fluorine-based resins can be used instead of inorganic fillers. As the fluorine-based resin, any known fluorine-containing resin such as PTFE (polytetrafluoroethylene) or PFA (perfluoroalkoxy alkane) can be used. As such a resin, Fluon+(registered trademark) EA-2000 of AGC Inc. can be exemplified. In the case of organic fillers, when their melting point and glass transition temperature are lower than 290°C which is the reflow soldering temperature, crosslinking of the organic filler itself is preferred from the viewpoint of heat resistance, and it is preferably blended in the form of fine particles or powder. By these organic fillers, an increase in the dielectric constant and the tangent of the dielectric loss angle can also be suppressed.

[0181] On the other hand, by mixing and dispersing a high dielectric constant insulator filler having a dielectric constant of preferably 3 to 10000, more preferably 5 to 10000 at 1 GHz in the composition of the present invention, an insulating cured body having a high dielectric constant insulating layer with an increase in the tangent of the dielectric loss angle (dielectric loss) suppressed and a dielectric constant of preferably 2.5 to 20, more preferably 2.8 to 10 can be produced. By increasing the dielectric constant of the film formed from the insulating cured body, miniaturization of the circuit and high capacitance of the capacitor can be achieved, which contributes to miniaturization of electrical components for high frequencies, etc. The high dielectric constant and low tangent of the dielectric loss angle insulating layer is suitable for uses such as capacitors, inductors for resonance circuits, filters, and antennas. As the high dielectric constant insulator filler used in the present invention, inorganic fillers or metal particles subjected to insulation treatment can be cited. Specific examples are known high dielectric constant inorganic fillers such as barium titanate and strontium titanate, and other examples are specifically described in, for example, Japanese Patent Laid-Open No. 2004-087639.

[0182] <Other Additives>

[0183] This composition may further contain one or more selected from flame retardants and surface modifiers. In order to be able to be the matrix of the cured body and have excellent filling properties for other materials during curing, the composition of the present invention contains one or more selected from these fillers, flame retardants, and surface modifiers, and even after curing, the cured body is liable to exhibit impact resistance and toughness.

[0184] <Flame Retardants>

[0185] Known flame retardants can be used in the composition of the present invention. From the viewpoint of maintaining a low dielectric constant and a low tangent of the dielectric loss angle, preferred flame retardants are known organophosphorus-based such as phosphoric esters or their condensates, known bromine-based flame retardants, and red phosphorus. Especially among phosphoric esters, compounds having multiple xylyl groups in the molecule are preferred from the viewpoints of flame retardancy and low tangent of the dielectric loss angle.

[0186] Furthermore, in addition to the flame retardant, as flame retardant aids, antimony compounds such as antimony trioxide, antimony tetroxide, antimony pentoxide, sodium antimonate, or nitrogen-containing compounds such as melamine, triallyl-1,3,5-triazine-2,3,4-(1H,3H,5H)-trione, 2,4,6-triallyloxy-1,3,5-triazine can also be added. With respect to 100 parts by mass of the composition, the total of these flame retardants and flame retardant aids is usually preferably 1 to 100 parts by mass. In addition, with respect to 100 parts by mass of the flame retardant, a resin having a low dielectric constant and excellent flame retardancy, such as a polyphenylene ether (PPE)-based resin, can be used in an amount of 30 to 200 parts by mass.

[0187] <Surface modifier>

[0188] In the composition of the present invention, for the purpose of improving the adhesion to the filler, copper plate, and wiring, various surface modifiers can be included. With respect to 100 parts by mass of the composition of the present invention other than the surface modifier, the amount of the surface modifier used is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass. As the surface modifier, various silane coupling agents, titanate coupling agents, etc. can be cited. One or more of various silane coupling agents and titanate coupling agents can be used.

[0189] In the present invention, the fluidization temperature of the present curable resin or composition can be adjusted according to its purpose and molding method by changing the mixing ratio of the "resin component", "curing agent", "monomer", "solvent", "filler", or "other additives". Specifically, the composition of the present invention can take product forms such as "thermoplastic composition", "semi-cured state (B-stage sheet, etc.)", and "varnish".

[0190] The composition of the present invention is obtained by mixing, dissolving, or melting one or more selected from the "resin component", "curing agent", "monomer", "solvent", "filler", and "other additives". Furthermore, in the range not impairing the object of the present invention, conventional additives added to conventional resins, such as lubricants, stabilizers, anti-aging agents, weather resistance agents, ultraviolet absorbers, etc., can be used. These methods of mixing, dissolving, and melting can adopt any known methods.

[0191] <Thermoplastic composition and its molded body>

[0192] The composition of the present invention uses a copolymer having a molecular weight of more than a certain value, usually in the range of about 50,000 or more in terms of weight average molecular weight, and when containing the specified resin component as described above, can exhibit the properties of a thermoplastic resin. Therefore, under conditions that do not cause crosslinking, it can be formed into shapes such as sheets, tubes, strips, and granules in a substantially uncured state by known molding processing methods for thermoplastic resins. The molded article can be crosslinked (cured) later or during molding.

[0193] In addition, a preferred embodiment of the present composition is as follows. When containing one or more resins selected from the above-mentioned hydrocarbon-based elastomers, polyether-based resins, olefin - aromatic vinyl compound - aromatic polyene copolymers without cyclic olefins, or aromatic polyene-based resins (except for resins that are liquid at room temperature) as resin components, similarly, the molding process as a thermoplastic resin in the uncured state becomes easy. The above thermoplastic composition can utilize its thermoplasticity below the action temperature of the curing agent, and can be preformed into various shapes such as sheets in advance. After being laminated and combined with semiconductor elements, wirings, or substrates as needed, it is heated and cured to make it adhere.

[0194] The composition of the present invention can be provided in the form of a sheet, which is obtained by molding a composition heated and melted at a temperature below the action temperature or decomposition temperature of the curing agent or a temperature lower than the action temperature or decomposition temperature of the curing agent by a known method. The molding into a sheet can be extrusion molding based on a T-die, two-roll processing, or extrusion lamination onto a substrate film. In this case, the composition, the mass ratio of the copolymer / monomer, or the selection and adjustment of the solvent, resin component, and flame retardant are carried out in such a way that it melts at a temperature below the action temperature or decomposition temperature of the curing agent or a temperature lower than the action temperature or decomposition temperature of the curing agent and becomes solid near room temperature. The sheet at this time is substantially in an uncured state. Then, through various processing and assembly processes, it is finally treated at a temperature and time above the action temperature or decomposition temperature of the curing agent to make it completely cured. Such a method is a common technique for ethylene - vinyl acetate resin-based crosslinking sealant sheets for solar cells (solar power generation devices).

[0195] <Molded article in a semi-cured state (B-stage sheet, etc.)>

[0196] In addition, the composition of the present invention can also be made into a partially crosslinked state, for example, a molded body in a semi-cured state (so-called B-stage state) obtained by reacting a part of the curing agent contained therein, such as a sheet, a tube, etc. Here, the semi-cured state is defined independently of the above-defined uncured state as: the proportion of the gel fraction as the resin component in the composition of the present invention is greater than 20% by mass and 80% by mass or less. It should be noted that the gel fraction is a value obtained by measurement in accordance with JIS K6796:1998. For example, by using a variety of curing agents and / or curing conditions with different curing temperatures, it can be semi-cured to control the melt viscosity and fluidity to become the B-stage state. That is, the curable resin and composition can also be formed into an easily processable B-stage sheet by the first-stage curing (partial curing), and after laminating and pressing it with an electronic device and a substrate, the second-stage curing (complete curing) is carried out to form the final shape. In this case, the composition of the composition, that is, the mass ratio of the copolymer / monomer, can be selected, a solvent, a resin component, and a flame retardant can be added as needed, and further, the composition containing a curing agent such as a peroxide is partially cured and adjusted to a sheet shape (B-stage state). After forming and assembling the device, it is heated under pressure to make it completely cured. As a method for partially curing the composition, a known method can be used. For example, there is the following method: peroxides with different decomposition temperatures are used in combination, and the treatment is carried out for a specified time at a temperature at which only one of them substantially acts to obtain a semi-cured sheet, and finally, the treatment is carried out for a sufficient time at a temperature at which all the curing agents act to make it completely cured.

[0197] In addition, the molded body can be a sheet. The sheet can be uncured (semi-cured) to the extent that it can maintain the sheet shape, or a completely cured sheet. The degree of curing of the composition can be quantitatively measured by a known dynamic viscoelasticity measurement method (DMA, Dynamic Mechanical Analysis).

[0198] <Varnish-like composition and its molded body>

[0199] The composition of the present invention can also be made into a viscous liquid-like varnish through its composition and mixing ratio. For example, by using a sufficient amount of solvent and / or by using an appropriate amount of liquid monomer, a varnish-like state can be achieved. Especially 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 when made into a varnish. As the solvent, when the boiling point under atmospheric pressure is high, that is, when the volatility is low, the thickness of the coated film becomes uniform, so a solvent having a boiling point of a certain degree or more is preferred. The preferred boiling point is generally 110°C or more and 300°C or less under atmospheric pressure. As such a solvent suitable for varnish, toluene, xylene, mesitylene, ethylbenzene, limonene, ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether, etc. can be used. In addition, its usage amount is preferably in the range of 10 to 2000 parts by mass relative to 100 parts by mass of the composition of the present invention.

[0200] This varnish is, for example, coated or impregnated on a substrate, and by removing the solvent, etc. through drying, etc., an uncured or semi-cured molded body can be made. Generally, this molded body has the form of a sheet, film, or strip. In this embodiment, the obtained uncured or semi-cured molded body is cured.

[0201] <Curing>

[0202] The curing of the composition can be carried out by a known method with reference to the curing conditions (temperature, time, pressure) of the curing agent contained. When the curing agent used is a peroxide, the curing conditions can be determined with reference to the half-life temperature, etc. disclosed for each peroxide.

[0203] <Cured body of the composition>

[0204] The dielectric constant and dielectric loss tangent of the cured body obtained from the composition of the present invention are measured by a known resonator method. In this specification, the resonator method is carried out at a measurement frequency of 40 GHz. The dielectric constant of this cured body is 3.5 or less, preferably can be 3.5 or less and 2.0 or more, and particularly preferably can be 3.0 or less and 2.0 or more. The dielectric loss tangent of this cured body is 0.0015 or less, can be 0.0002 or more and 0.0015 or less, and preferably can be 0.0005 or more and 0.0010 or less. In addition, the volume resistivity of this cured body is preferably 1×10 15Above Ω·cm. These values are preferably used as high-frequency electrical insulating materials, for example, above 3 GHz. The copolymer used in the composition of the present invention is relatively soft and has excellent tensile elongation. Therefore, the cured body obtained from the composition using it can have the following characteristics: showing sufficient mechanical properties, having high impact resistance, and being able to follow the thermal expansion of the substrate. That is, for the cured body of the present invention, the storage elastic modulus measured at room temperature (25 °C) is preferably 0.1 GPa or more and 30 GPa or less, more preferably 0.1 GPa or more and less than 30 GPa, and further preferably 1 GPa or more and 20 GPa or less. In addition, for the storage elastic modulus measured at high temperature (280 °C), it is preferably 1 MPa or more and 1 GPa or less, more preferably 5 MPa or more and 1 GPa or less, and further preferably 10 MPa or more and 1 GPa or less. Those skilled in the art can determine the formulation of the composition having the above physical property parameters and produce a cured body with reference to the information described in this specification and known materials. The cured body obtained from the composition of the present invention can exhibit practically sufficient heat resistance and mechanical properties at high temperature even under the condition that the monomers in the composition and the aromatic polyene as a monomer component are suppressed to a certain proportion or less.

[0205] <General uses of the composition>

[0206] The composition of the present invention can be used as 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. In addition, it can also be used as various electrical insulating materials for wiring (preferably for high-frequency signal wiring), such as cover layers, high-frequency transmission circuits, antennas, solder masks, build-up materials, interlayer insulating materials, bonding sheets, interlayer adhesives, and bump sheets for flip-chip bonding machines.

[0207] From another perspective, the present invention can provide an electrical insulating material comprising an olefin-aromatic vinyl compound-aromatic polyene copolymer (which can be an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer). As a cured body, the storage elastic modulus at 250 °C is 10 MPa or more and 10 GPa or less, and the dielectric constant measured under the conditions of 23 °C and 40 GHz is 2.0 or more and 3.5 or less, and the dielectric loss tangent is 0.0015 or less, more preferably 1.2×10 -3 Below.

[0208] In one embodiment of the present invention, a method for producing the above copolymer can also be provided. As this production method, a production method of the above copolymer in which α-olefins, cyclic olefins, and aromatic polyenes are copolymerized by coordination polymerization can be cited. In addition, in another embodiment, a production method of a cured product can also be provided, which includes a step of polymerizing the above copolymer using a radical polymerization initiator whose structure contains no oxygen atoms or nitrogen atoms and is composed only of carbon atoms and hydrogen atoms.

[0209] Coordination polymerization refers to a polymerization method using a coordination polymerization catalyst containing a transition metal compound and a cocatalyst. As the transition metal compound, a transition metal compound containing zirconium, hafnium, titanium, iron, nickel, cobalt, or palladium is preferred. In particular, in order to copolymerize cyclic olefin monomers, a transition metal compound containing zirconium, titanium, nickel, iron, or palladium is preferred. The most preferably used coordination polymerization catalyst can be a coordination polymerization catalyst containing a transition metal compound represented by the following general formula (1) and a cocatalyst. As this production method, it is further preferably possible to include the following steps: using a polymerization catalyst containing a transition metal compound represented by the following general formula (1) and a cocatalyst, copolymerizing each monomer of α-olefins, cyclic olefins, (when included) aromatic vinyl compounds, and aromatic polyenes.

[0210] General formula (1)

[0211] [Chemical formula 4]

[0212]

[0213] In the above formula, A and B are each independently a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzoindenyl group, an unsubstituted or substituted cyclopentadienyl group, or an unsubstituted or substituted indenyl group.

[0214] Y is a methylene group, a silylene group, an ethylene group, a germylene group, or a boron residue that has a bond with A and B and has a hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as a substituent. The substituents may be different or the same from each other. In addition, Y may have a cyclic structure. As Y, a methylene group that has a bond with A and B and has a 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 is most preferably used.

[0215] 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 a hydrocarbon substituent having 1 to 4 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having an alkyl substituent having 1 to 6 carbon atoms.

[0216] M is a transition metal, preferably zirconium, hafnium, or titanium.

[0217] In order to provide a copolymer having a low molecular weight and a low viscosity when made into a varnish, preferably, A and B in the above general formula (1) can each independently be a group selected from unsubstituted or substituted cyclopentadienyl groups, or unsubstituted or substituted indenyl groups, and a transition metal compound having both an unsubstituted or substituted cyclopentadienyl group and an unsubstituted or substituted indenyl group is particularly preferably used. In order to provide a copolymer having a high aromatic polyene content, that is, a copolymer having a high number of vinyl and / or vinylene groups from aromatic polyene monomer units per unit number-average molecular weight, a transition metal compound having at least one group selected from unsubstituted or substituted indenyl groups and unsubstituted or substituted benzoindenyl groups is preferably used. In the case of a copolymer having a high aromatic polyene content, the crosslinking density of the cured product obtained by curing can be increased. For example, a cured body having a storage elastic modulus of 5 MPa or more measured at 280 °C can be obtained.

[0218] As the cocatalyst in the polymerization catalyst of the present invention, a known cocatalyst used in combination with a transition metal compound can be used. As such a cocatalyst, aluminum compounds and boron compounds are preferably cited. As the aluminum compound, an alumoxane such as methyl alumoxane (or denoted as methyl alumoxane or MAO) is preferably used. In addition, an alkylaluminum such as triisobutylaluminum or triethylaluminum can be used. Examples of such a cocatalyst include the cocatalysts and alkylaluminum compounds described in European Patent Application Publication No. 0872492 A2, Japanese Patent Laid-Open No. 11-130808, Japanese Patent Laid-Open No. 9-309925, International Publication No. 00 / 20426, European Patent Application Publication No. 0985689 A1, and Japanese Patent Laid-Open No. 6-184179.

[0219] Examples of the boron compound include tris(pentafluorophenyl)borane, triphenylcarbenium tetrakis(pentafluorophenyl)borate {triphenylmethyltetrakis(pentafluorophenyl)borate}, lithium tetrakis(pentafluorophenyl)borate, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, tri(n-butyl)ammonium tetrakis(p-tolyl)phenylborate, tri(n-butyl)ammonium tetrakis(p-ethylphenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, trimethylammonium tetrakis(p-tolyl)borate, trimethylammonium tetrakis(3,5-dimethylphenyl)borate, triethylammonium tetrakis(3,5-dimethylphenyl)borate, tributylammonium tetrakis(3,5-dimethylphenyl)borate, tributylammonium tetrakis(2,4-dimethylphenyl)borate, anilinium tetrakis(pentafluorophenyl)borate, N,N'-dimethylanilinium tetraphenylborate, N,N'-dimethylanilinium tetrakis(p-tolyl)borate, N,N'-dimethylanilinium tetrakis(m-tolyl)borate, N,N'-dimethylanilinium tetrakis(2,4-dimethylphenyl)borate, N,N'-dimethylanilinium tetrakis(3,5-dimethylphenyl)borate, N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N'-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N'-2,4,5-pentamethylanilinium tetraphenylborate, N,N'-2,4,5-pentaethylanilinium tetraphenylborate, bis(isopropyl)ammonium tetrakis(pentafluorophenyl)borate, dicyclohexylammonium tetraphenylborate, triphenylphosphonium tetraphenylborate, tris(methylphenyl)phosphonium tetraphenylborate, tris(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 tetrakis(pentafluorophenyl)borate, tropylium tetrakis(p-tolyl)borate, tropylium tetrakis(m-tolyl)borate, tropylium tetrakis(2,4-dimethylphenyl)borate, tropylium tetrakis(3,5-dimethylphenyl)borate, and the like. Among these, the most preferred boron cocatalyst is a boron cocatalyst having boron and a fluorine-substituted aromatic group bonded thereto. Examples of such include tris(pentafluorophenyl)borane, triphenylcarbenium tetrakis(pentafluorophenyl)borate {triphenylmethyltetrakis(pentafluorophenyl)borate}, lithium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, tropylium tetrakis(pentafluorophenyl)borate, N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate, and the like. Here, as an example of the fluorine-substituted aromatic group, the case of phenyl is exemplified, but similarly, a fused aromatic group such as a fluorine-substituted naphthyl group can also be preferably used.

[0220] The cocatalyst is used in a ratio of 0.1 to 100,000, preferably 10 to 10,000, in terms of the ratio of aluminum atoms to transition metal atoms relative to the metal of the transition metal compound. When it is 0.1 or more, the transition metal compound can be effectively activated, and when it is 100,000 or less, it is economically advantageous. The transition metal compound and the cocatalyst can be mixed and prepared outside the polymerization equipment, or can be mixed inside the equipment during polymerization.

[0221] In particular, cocatalysts such as aluminoxane are preferably in a ratio of 0.1 to 100,000, more preferably 10 to 10,000, in terms of the ratio of aluminum atoms to transition metal atoms relative to the metal of the transition metal compound. When it is 0.1 or more, the transition metal compound can be effectively activated, and when it is 100,000 or less, it is economically advantageous. In the case of using a boron compound as the cocatalyst, the ratio in terms of boron atoms to transition metal atoms is preferably in the range of 0.1 to 100, more preferably 0.1 to 10, and most preferably 0.8 to 1.2. When it is 0.1 or more, the transition metal compound can be effectively activated, and when it is 100 or less, it is economically advantageous.

[0222] In a preferred embodiment, a cocatalyst containing a boron compound as an essential component and optionally containing an aluminum compound can be used. By using a boron compound as the cocatalyst, the amount of metal components such as aluminum derived from the aluminum compound contained in the finally obtained copolymer can be reduced, and the values of the dielectric constant and the dissipation factor of the finally obtained uncured copolymer, or the dielectric constant and the dissipation factor of a single cured body or composition can be reduced to a particularly preferred range. For example, the dielectric constant of the uncured copolymer can be made less than 2.3, and the dissipation factor can be made less than 0.0004. In addition, in the case of using a boron compound as the cocatalyst, the dielectric constant of the cured body of the finally obtained copolymer alone can also be made less than 2.3, and the dissipation factor can be made less than 0.0004.

[0223] In one embodiment, 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 from a catalyst and a cocatalyst can be provided. Here, the metal content from the catalyst and the cocatalyst is defined as the total content of the transition metal element (the above element) used in the catalyst and boron and / or aluminum from the boron compound and / or aluminum compound used in the cocatalyst, and can be defined as the total content of each element of zirconium, hafnium, titanium, iron, nickel, palladium, cobalt, boron, and aluminum. Particularly preferably, the metal from the catalyst can be zirconium, the metals from the cocatalyst can be aluminum and boron, and the metal content from the catalyst and the cocatalyst can be the total content of these zirconium, aluminum, and boron. It should be noted that in this specification, boron is included in the category of metals. The 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 elastic modulus measured at 25 °C of 1000 MPa or more. More preferably, for the uncured copolymer, the dielectric constant at a measurement frequency of 40 GHz can be less than 2.3, the dielectric loss tangent can be less than 0.0004, and the storage elastic modulus measured at 25 °C can be 1000 MPa or more.

[0224] Examples

[0225] Hereinafter, the present invention will be described by way of examples, but the present invention is not construed as being limited to the following examples.

[0226] The analysis of the copolymer obtained in the synthesis example was carried out by the following means.

[0227] For the determination of the content of vinyl units from ethylene, cyclic olefin, and divinylbenzene in the copolymer, 1 1H-NMR measurement and 13 13C-NMR measurement in the quantitative mode were carried out according to the known method based on the area intensity of the obtained peaks. The sample was dissolved in deuterated 1,1,2,2-tetrachloroethane, and the measurement was carried out at 80 to 130 °C.

[0228] Regarding the molecular weight, the number average molecular weight (Mn) in terms of standard polystyrene was determined using GPC (gel permeation chromatography). The measurement was carried out under the following conditions.

[0229] Column: Two TSK-GEL MultiporeHXL-M (manufactured by Tosoh Corporation) were connected in series and used.

[0230] Column temperature: 40 °C

[0231] Solvent: THF

[0232] Liquid delivery flow rate: 1.0 ml / min.

[0233] Detector: RI detector

[0234] <Viscosity>

[0235] The viscosity of the copolymer obtained in each example was determined as follows.

[0236] A 25 mass% toluene solution of each copolymer was prepared, and using a rotational rheometer (MCR302: manufactured by Anton Paar), measurements were carried out at 25 °C, using a shear rate of 1 sec -1 value.

[0237] <Gel fraction>

[0238] According to ASTM D2765-84, the gel fraction as the boiling toluene-insoluble component was determined.

[0239] <Water absorption>

[0240] According to ASTM D570-98, the water absorption after immersion in pure water at 23 °C for 24 hours was measured.

[0241] <Dielectric constant and dielectric loss (tangent of the loss angle)>

[0242] Regarding the tangent of the loss angle, using the cavity resonator perturbation method (Agilent Technologies 8722ES type network analyzer, Keysight Technologies split cylinder resonator 40 GHz), a sample of 0.1 mm × 25 mm × 30 mm cut from the sheet was used, and the value under the conditions of 23 °C and 40 GHz was measured. Measurements were carried out separately for the uncured state and the cured state.

[0243] <Measurement of storage elastic modulus>

[0244] Using a dynamic viscoelasticity measuring device (TA Instruments, formerly RSA-G2 of Rheometrics), while heating from room temperature (23 °C) at a frequency of 1 Hz, the storage elastic modulus at 25 °C and the storage elastic modulus at 280 °C were measured. A measurement sample (3 mm × 40 mm) was cut from a film with a thickness of about 0.1 mm and measured, and the storage elastic modulus was measured for both the uncured state and the cured body state. In addition, the glass transition temperature was also determined from the peak temperature of the dielectric loss tangent (tanδ) in the uncured state.

[0245] The main measurement parameters related to the measurement are as follows.

[0246] Measurement frequency: 1 Hz

[0247] Heating rate: 3 °C / minute

[0248] Sample measurement length: 10 mm

[0249] Strain: 0.1%

[0250] <Quantification of the metal content in the copolymer>

[0251] The metal content (in the following examples, the content of the transition metal element used in the metal catalyst, boron and aluminum used in the cocatalyst respectively) was carried out as follows. Furthermore, the contents of hafnium, titanium, iron, nickel, cobalt, and palladium were also quantified.

[0252] Under the following conditions in accordance with JIS K 0116:2014, ICP emission spectrometry was used for the measurement.

[0253] Weighed 0.5 g of the composition to be measured into a platinum crucible, and ashed it using a hot plate, an electric furnace, and an electric furnace (heating gradually to 600 °C). Added 0.5 ml of HCl (1+1) (that is, a mixed solution of hydrochloric acid and water with a volume ratio of 1:1) and ultrapure water to the residue, heated and dissolved it, and then fixed the volume to 5 ml to obtain a test solution, and carried out quantitative analysis using ICP emission spectrometry (using 5110VDV manufactured by Agilent).

[0254] <Example 1: Manufacture of copolymer P-1>

[0255] As the raw material divinylbenzene (DVB), the product named "Divinylbenzene (96%)" manufactured by NIPPON STEEL CHEMICAL&MATERIAL CO., LTD. was used (liquid at room temperature, containing 96% by mass of divinylbenzene in the form of a mixture of meta-isomer and para-isomer, and the balance being ethyl vinylbenzene). As the raw material, norbornene (concentration 75%, toluene solution) manufactured by Maruzen Petrochemical Co., Ltd. was used. A small amount of triisobutylaluminum (TIBA) was added in advance, stirred at room temperature, and then distilled and purified under nitrogen for use. A 10 L polymerization tank equipped with a heating and cooling jacket and a stirrer was used. First, the inside of the sufficiently dried polymerization tank was purged with nitrogen, 3 kg of toluene, 1 kg of norbornene in terms of pure amount, and 180 g of divinylbenzene in terms of pure amount were charged, and about 20 L of dry nitrogen was bubbled at an internal temperature of 50°C. Then, the inside of the polymerization tank was purged with ethylene gas, 5 mmol of TIBA (manufactured by Kanto Chemical Co., Inc.) in terms of the molar amount of aluminum was added and stirred, and further 50 mmol of MMAO (modified MAO) manufactured by Tosoh Finechem Corporation in terms of aluminum was added and stirred. The internal temperature was stabilized at 60°C, the internal pressure of the polymerization tank was increased to 0.4 MPaG (gauge pressure) by supplying ethylene and stabilized, and then 100 g of a toluene solution containing 100 μmol of racemic diphenylmethylene(1-indenyl)(cyclopentadienyl)zirconium dichloride (the structure is shown in the following formula (2)) and 2 mmol of TIBA was added to the polymerization tank from the catalyst tank provided on the polymerization tank to start the polymerization. The ethylene consumed during the polymerization was gradually replenished, and the polymerization was continued while maintaining the internal temperature at 60°C and the internal pressure at 0.4 MPaG. After about 2 hours of polymerization time, when the ethylene consumption reached 200 g, the ethylene gas in the polymerization tank was discharged, the pressure was restored to normal pressure, 50 g of isopropyl alcohol as a polymerization terminator was added to the polymerization tank, and the polymerization was stopped. The obtained polymerization solution was successively added in small amounts to a sufficiently large amount of methanol / acetone mixed solution, the precipitated polymer was stirred and filtered, whereby the polymer was recovered, and vacuum dried sufficiently at room temperature to obtain P-1 as an ethylene-norbornene-divinylbenzene copolymer.

[0256] Formula (2)

[0257] [Chemical formula 5]

[0258]

[0259] <Example 2: Manufacture of Copolymer P-2>

[0260] The same operation as the synthesis of P-1 described above was carried out, where the amount of norbornene used was changed to 1.4 kg on a pure basis for polymerization, and the polymerization was stopped when the ethylene consumption reached 100 g, to obtain P-2 as an ethylene-norbornene-divinylbenzene copolymer.

[0261] <Example 3: Manufacture of Copolymer P-3>

[0262] The same operation as the synthesis of P-1 described above was carried out. Regarding the amounts of raw materials used, toluene was changed to 2 kg, norbornene was changed to 2 kg on a pure basis, divinylbenzene was changed to 300 g on a pure basis, MMAO (modified MAO) manufactured by Tosoh Finechem Corporation was changed to 100 mmol in terms of aluminum. Furthermore, the catalyst used was changed to a toluene solution of 100 g containing 200 μmol of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride (the structure is shown in the following formula (3)) and 4 mmol of TIBA, and polymerization was carried out. The polymerization was stopped at the time point when the ethylene consumption reached 150 g, to obtain P-3 as an ethylene-norbornene-divinylbenzene copolymer.

[0263] Formula (3)

[0264] [Chemical formula 6]

[0265]

[0266] <Example 4: Manufacture of Copolymer P-4>

[0267] The same as the synthesis of P-3 described above, dimethylmethylenebis(cyclopentadienyl)zirconium dichloride was used as the catalyst, but MMAO was not used as the cocatalyst, and it was changed to lithium tetrakis(pentafluorophenyl)borate (manufactured by Tosoh Finechem Corporation) instead. That is, a catalyst solution was added in which 125 μmol of lithium tetrakis(pentafluorophenyl)borate was stirred and dissolved in 200 ml of a toluene solution containing 110 μmol of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 2 mmol of triisobutylaluminum, and polymerization was carried out at an internal temperature of 90 °C during the polymerization temperature. The polymerization was stopped at the time point when the ethylene consumption reached 150 g, to obtain P-4 as an ethylene-norbornene-divinylbenzene copolymer.

[0268] P-1 to P-4 obtained in each example contained a small amount of residual monomers and solvents. Therefore, they were redissolved in toluene, and the solution was gradually added in small amounts to a sufficiently large amount of methanol / acetone mixed solution. The precipitated polymer was stirred and filtered, and dried at room temperature under vacuum for 24 hours to obtain a purified polymer. The compositions and molecular weights of the obtained P-1 to P-4 are shown in Table 1. The purified polymer was redissolved in toluene to prepare a 50 mass% toluene solution (varnish). The varnish was coated on a smooth Teflon (registered trademark) plate with an applicator, air-dried at 25 °C for more than 3 hours, further dried at 120 °C under vacuum for 12 hours, and then dried at 200 °C under vacuum for 60 minutes to obtain a transparent sheet with a thickness of 0.1 mm. The sheet was finely cut, and the gel fraction was measured. According to the measurement results of the gel fraction, it was confirmed that the sheet was in an uncured state. Using this sheet, the viscoelastic spectrum (DMA) was measured, and the storage elastic modulus and glass transition temperature at 25 °C were measured. Using this sheet, the dielectric properties were measured. Their results are shown in Table 1. It was found that the copolymer of the present invention showed a high glass transition temperature in the uncured state, and showed a high storage elastic modulus (at 25 °C), a low dielectric constant, and a low dielectric loss tangent value. In particular, P-4 obtained using a boron compound as a cocatalyst showed a low dielectric constant and a significantly low dielectric loss tangent.

[0269] [Table 1a]

[0270]

[0271] [Table 1b]

[0272]

[0273] <Example 5: Production of Cured Sheet>

[0274] Using a container equipped with a jacket for heating and cooling and a stirring blade, 100 parts by mass of P-1 (ethylene-norbornene-divinylbenzene copolymer) was heated to about 50 °C in 100 parts by mass of the solvent toluene, and stirred to dissolve the copolymer, thereby preparing a 50 mass% toluene solution (varnish). Further, 1 part by mass of a curing agent (PERBUTYL P) was added based on the parts by mass of the copolymer, dissolved, and stirred and mixed to obtain a varnish-like composition (Table 2). The resulting composition was poured into a Teflon (registered trademark) mold frame (frame part length: 7 cm, width: 7 cm, thickness: 0.2 mm, 0.5 mm, or 1.0 mm) placed on a PET sheet on a glass plate, air-dried sufficiently at 25 °C, and then dried in a vacuum dryer at 60 °C for 3 hours or more to obtain an uncured sheet. Further, using a press, a Teflon sheet and a Teflon mold frame were placed under a load of 5 MPa, heat-treated at 120 °C for 30 minutes, heat-treated at 150 °C for 30 minutes, and then heat-treated at 200 °C for 120 minutes. The Teflon sheet and the Teflon mold frame were removed to obtain a cured sheet. The gel fraction, storage elastic modulus (at 25 °C and 280 °C), dielectric constant, and dielectric loss tangent (all measured under the conditions of 23 °C and 40 GHz) and water absorption of the obtained cured sheet were determined.

[0275] <Example 6: Production of Cured Sheet>

[0276] Operating in the same manner as in Example 5, a cured sheet was obtained, and the physical property values were determined in the same manner.

[0277] <Examples 7 to 8: Production of Cured Sheet>

[0278] P-3 and P-4 with a glass transition temperature of 150 °C or higher are more difficult to remove residual toluene in the polymer than P-1 and P-2. The cured sheet was obtained in the following manner, and the physical property values were similarly determined. Using the same containers as in Examples 5 and 6, 100 parts by mass of P-3 or P-4 (ethylene-norbornene-divinylbenzene copolymer) was heated to about 50 °C in 100 parts by mass of the solvent toluene and stirred to dissolve the copolymer, and a 50 mass% toluene solution (varnish) was prepared. Further, 1 part by mass of a curing agent (2,3-dimethyl-2,3-diphenylbutane, manufactured by Kanto Chemical Co., Inc.) was added based on the parts by mass of the copolymer, dissolved, and stirred and mixed to obtain a varnish-like composition (Table 2). The obtained composition was poured into a Teflon (registered trademark) mold frame (frame part length 7 cm, width 7 cm, thickness 0.1 mm) placed on a PET sheet on a glass plate, air-dried sufficiently at 25 °C, and then further dried in a vacuum dryer at 100 °C for 3 hours to obtain an uncured sheet substantially free of solvent. A plurality of the uncured sheets were overlapped to form the required thickness for each measurement, and using a vacuum press, a Teflon sheet and a Teflon mold frame were set under a load of 5 MPa, and heat-treated at 250 °C for 60 minutes. The Teflon sheet and the Teflon mold frame were removed to obtain a cured sheet. The gel fraction, storage elastic modulus (at 25 °C and 280 °C), dielectric constant, and dielectric loss tangent (all measured under the conditions of 23 °C and 40 GHz) and water absorption rate of the obtained cured sheet were determined.

[0279] Table 2 shows the formulation (the unit in the table is parts by mass) and physical property values (gel fraction, storage elastic modulus at 25 °C and 280 °C, dielectric constant, dielectric loss tangent, water absorption rate). In addition, the viscosities of the 25 mass% toluene solutions (varnishes) of each example are shown in Table 2. The cured sheets obtained in Examples 5 to 8 showed a high gel fraction and were sufficiently cured, and had sufficient hardness as a substrate, especially a rigid substrate, in terms of the storage elastic modulus at room temperature (25 °C). In addition, they showed a low dielectric constant and low dielectric loss tangent values required for a high-frequency insulating material. The cured sheets obtained in Examples 5 and 6 showed a high storage elastic modulus at high temperature (280 °C) and had high mechanical properties at high temperature. In addition, the viscosities of the 25 mass% toluene solutions (varnishes) containing the copolymer obtained in Examples 5 and 6 were both 10,000 mPa·s or less. The cured sheet obtained in Example 8 showed particularly low dielectric constant (2.1) and dielectric loss tangent value (0.0002).

[0280] [Table 2]

[0281]

[0282] ※1 part by mass is added relative to a total of 100 parts by mass of raw materials other than the curing agent and the solvent

[0283] <Example 9: Production of Copolymer P-5>

[0284] Polymerization, polymer recovery, and post-treatment were carried out in the same manner as in the production method of the aforementioned P-4. Among them, 1.5 kg of norbornene, 2.5 kg of toluene, and 200 g of divinylbenzene in pure quantity were charged. As the catalyst, a catalyst solution prepared by adding 210 μmol of lithium tetrakis(pentafluorophenyl)borate to 300 mL of a toluene solution containing 200 μmol of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 5 mmol of triisobutylaluminum and stirring to dissolve was added. Polymerization was carried out while maintaining the internal pressure in the polymerization tank at 0.15 MPaG (gauge pressure) by supplying ethylene at a polymerization temperature of 60°C. In the middle, an equal amount of the same catalyst solution as the aforementioned catalyst solution was further added. Polymerization was stopped when the ethylene consumption reached 100 g, and P-5, an ethylene-norbornene-divinylbenzene copolymer, was obtained.

[0285] <Example 10: Production of Copolymer P-6>

[0286] Polymerization, polymer recovery, and post-treatment were carried out in the same manner as in the production method of the aforementioned P-5. Among them, 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, and P-6, an ethylene-MPNB-divinylbenzene copolymer, was obtained.

[0287] <Example 11: Production of Copolymer P-7>

[0288] Polymerization, polymer recovery, and post-treatment were carried out in the same manner as in the production method of the aforementioned P-5. Among them, 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, and P-7, an ethylene-MPNB-divinylbenzene copolymer, was obtained.

[0289] <Example 12: Production of Copolymer P-8>

[0290] As the raw material divinylbenzene (DVB), product name "divinylbenzene (81%)" manufactured by NIPPON STEEL CHEMICAL & MATERIAL CO., LTD. was used (liquid at room temperature, containing 81% by mass of divinylbenzene in the form of a mixture of meta- and para-isomers, and the remainder being ethylvinylbenzene). As the raw material, norbornene (75% concentration, toluene solution) manufactured by Maruzen Petrochemical Co., Ltd. was used, a small amount of triisobutylaluminum (TIBA) was added in advance, and after stirring at room temperature, it was purified by distillation under nitrogen before use. A 10L polymerization tank equipped with a heating and cooling jacket and a stirrer was used. First, the fully dried polymerization tank was purged with nitrogen, and 2kg of toluene, 1kg of norbornene in pure amount, and 2kg of divinylbenzene in mass as 81% divinylbenzene were added, and about 20L of dry nitrogen was blown in at an internal temperature of 50°C. Then, the polymerization tank was replaced with nitrogen, and 6 mmol of TIBA (manufactured by Kanto Chemical Co., Ltd.) was added and stirred based on the molar number of aluminum. The internal temperature was stabilized at 60°C, and the internal pressure of the polymerization tank was raised to 0.1 MPaG (gauge pressure) by nitrogen. After stabilization, the following catalyst solution was added to the polymerization tank from the catalyst tank provided on the polymerization tank as a catalyst to start polymerization. The catalyst solution was prepared by adding 210 μmol of lithium tetrakis (pentafluorophenyl) borate to 100 g of a toluene solution containing 200 μmol of dimethylmethylenebis (cyclopentadienyl) zirconium dichloride and 2 mmol of TIBA, and dissolving and stirring it. At an internal temperature of 60°C, the polymerization was continued while the internal pressure was maintained at 0.1 MPaG. After 4 hours of polymerization, 50 g of isopropyl alcohol as a polymerization terminator was added to the polymerization tank to stop polymerization. The obtained polymer solution was gradually added in small amounts into a sufficiently large amount of a methanol / acetone mixed solution, and the precipitated polymer was stirred and filtered to recover the polymer, which was then fully vacuum dried at room temperature to obtain P-8, which is a norbornene-ethylvinylbenzene-divinylbenzene copolymer.

[0291] <Example 13: Production of Copolymer P-9>

[0292] 2.2 kg of toluene, 1.5 kg of DMON in pure amount, 300 g of styrene and 200 g of divinylbenzene in pure amount were added to the polymerization tank, and copolymerization of ethylene, DMON, styrene and divinylbenzene was carried out in the same manner as in the production method of P-6. The polymerization was stopped when the ethylene consumption reached 100 g, and post-treatment was carried out in the same manner to obtain P-9, which was an ethylene-MPNB-ethylvinylbenzene-divinylbenzene copolymer.

[0293] Table 1 shows the composition, molecular weight, gel fraction, glass transition temperature, storage elastic modulus at 25°C, dielectric properties, and metal content of the copolymer of P-5 to P-9. It can be seen that the copolymers P-5 to P-9 obtained using a boron compound as a cocatalyst exhibit a high glass transition temperature in the uncured state, and exhibit a high storage elastic modulus (at 25°C) and significantly low dielectric constant and dielectric loss tangent value.

[0294] Regarding the copolymers obtained using DMON and MPNB as cyclic olefins, even when the molar contents of DMON and MPNB are small, a high glass transition temperature can be imparted. That is, when the DMON content of P-6 is expressed as a molar content, it is 52 mol%, and the MPNB content of P-7 is 46 mol%. The molar contents are lower than the norbornene content of P-5, which is 74 mol%. However, regarding the glass transition temperature, P-6 is 198°C, and P-7 is 186°C, which is approximately the same as 190°C of P-5. When the molar content of the cyclic olefin component is low, it is easy to replace the remaining monomer components with aromatic vinyl compound units, and a copolymer with a higher content of aromatic vinyl compound units can be provided. That is, it is possible to increase the aromaticity of the copolymer while maintaining a high glass transition temperature, and it is possible to improve the compatibility with other resins and raw materials, so it is preferred. An example is shown in P-9. In particular, regarding MPNB, since the cyclic olefin itself has an aromatic group, it is further preferred in this regard. In addition, the copolymers obtained using DMON and MPNB as cyclic olefins exhibit the following characteristics: they have a similarly high glass transition temperature, and the molecular weight of the copolymer is low. Specifically, by using DMON and MPNB as cyclic olefins, it is possible to easily achieve a most preferred number average molecular weight of 12,000 or less or less than 12,000. When the reduction of the molecular weight is easy, it is easy to manufacture a varnish with a lower viscosity, so it is preferred.

[0295] P-5 to P-9 obtained in each example contained a small amount of residual monomers and solvents. Therefore, they were redissolved in toluene, and the solution was gradually added in small amounts to a sufficiently large amount of a methanol / acetone mixed solution. The precipitated polymer was stirred and filtered, and dried under vacuum at room temperature for 24 hours to obtain a purified polymer. The compositions and molecular weights of the obtained P-5 to P-9 are shown in Table 1. The purified polymer was redissolved in toluene to prepare a 50 mass% toluene solution (varnish). The varnish was coated on a smooth Teflon (registered trademark) plate using an applicator, air-dried at 25°C for 3 hours or more, further 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. The sheet was finely cut, and the gel fraction was measured. Based on the measurement results of the gel fraction, it was confirmed that the sheet was in an uncured state. Using this sheet, the viscoelastic spectrum (DMA) was measured, and the storage elastic modulus and glass transition temperature at 25°C were measured. Using this sheet, the dielectric properties were measured. Their results are shown in Table 1. It was found that the copolymer of the present invention showed a high glass transition temperature in the uncured state, and showed a high storage elastic modulus (at 25°C), a low dielectric constant, and a low dielectric loss tangent value. It was found that P-5 to P-9 obtained using a boron compound as a cocatalyst showed a low dielectric constant and a low dielectric loss tangent.

[0296] 13C-NMR measurement of the norbornene-ethyl vinylbenzene-divinylbenzene copolymer of P-8 was carried out to investigate the terminal structures contained. As a result, no terminal structures other than the aforementioned E-1 to E-8 were detected. In addition, no terminal structures characteristic of cationic polymerization (structures denoted as t1 and t2 in International Publication No. 2018 / 181842) described in International Publication No. 2018 / 181842 were detected in P-8.

Claims

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

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

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

4. The copolymer according to any one of claims 1 to 3, wherein The total metal content from the catalyst and cocatalyst 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 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.

6. The copolymer according to claim 5, wherein, When cured alone, 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.

7. The copolymer according to any one of claims 1 to 6, wherein, When cured alone, the cured product has a storage elastic modulus measured at 280°C of 1 MPa or more.

8. The copolymer according to any one of claims 1 to 7, wherein, When cured alone, the cured product has a storage elastic modulus measured at 280°C of 5 MPa or more.

9. The copolymer according to claim 1, 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 multiple vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups from the aromatic polyene monomer unit is 2 or more and 30 or less per unit number average molecular weight; (6) The total of the α-olefin unit, cyclic olefin unit, and aromatic polyene unit is 100% by mass.

10. The copolymer according to claim 2, which satisfies all of the following (1) 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; (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 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 multiple vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups from the aromatic polyene monomer unit is 2 or more and 30 or less per unit number average molecular weight; (6) The total of the α-olefin unit, cyclic olefin unit, aromatic vinyl compound unit, and aromatic polyene unit is 100% by mass.

11. The copolymer according to any one of claims 1 to 10, wherein, The cyclic olefin unit contains 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, having a glass transition temperature in the range of 100 °C or higher and 350 °C or lower.

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

14. A method for producing the copolymer according to any one of claims 1 to 13, which copolymerizes each monomer of an α-olefin, a cyclic olefin, an aromatic polyene, and, if necessary, an aromatic vinyl compound by coordination polymerization using a coordination polymerization catalyst.

15. The method for producing the 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 cocatalyst. General formula (1) [Chemical formula 1] In the formula, A and B are each independently a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzoindenyl group, an unsubstituted or substituted cyclopentadienyl group, or an unsubstituted or substituted indenyl group. Y is a methylene group, a methylsilyl group, an ethylene group, a methylgermyl group, or a boron residue that has a bond with A and B and has a hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as a substituent; the substituents may be different or the same; in addition, 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 a hydrocarbon substituent having 1 to 4 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having an alkyl substituent having 1 to 6 carbon atoms. M is zirconium, hafnium, or titanium.

16. The method for producing the copolymer according to claim 15, wherein, In general formula (1), A and B are each independently a group 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 Use a cocatalyst containing a boron compound.

18. The manufacturing method according to claim 17, wherein, The cocatalyst further contains an aluminum compound.

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

20. A solidified body which is a solidified body of the following composition, the composition comprising: an α-olefin-cyclic olefin-aromatic polyene copolymer satisfying all of the following (1) to (2), (4) to (6); and one or more additive components selected from the group consisting of a resin component, a curing agent, a monomer, a solvent, and a filler. (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 from the aromatic polyene monomer unit is 2 or more and 30 or less per unit 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; The dielectric constant of the cured body at a measurement frequency of 40 GHz is 3.5 or less, and the tangent of the dielectric loss angle is 0.0015 or less.

21. A cured body which is a cured body of the following composition, the composition comprising: an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following (1) to (6); and one or more additive components selected from the group consisting of a resin component, a curing agent, a monomer, a solvent, and a filler, (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; (3) The aromatic vinyl compound unit is an aromatic vinyl compound having 8 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 unit number average molecular weight; (6) The total of the α-olefin unit, the cyclic olefin unit, the aromatic vinyl compound unit, and the aromatic polyene unit is 100% by mass, The dielectric constant of the cured body at a measurement frequency of 40 GHz is 3.5 or less, and the tangent of the dielectric loss angle is 0.0015 or less.

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

23. The 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 cover layer, a high-frequency transmission circuit, or an antenna, which comprises the cured body according to claim 23.

25. A method for producing a cured body, which at least includes the following step: polymerizing the copolymer according to any one of claims 1 to 13 using a radical polymerization initiator whose structure contains no oxygen atoms or nitrogen atoms and is composed only of carbon atoms and hydrogen atoms.

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