Resin composition, curing method therefor, and cured body

Abstract

Provided is a resin composition having excellent low dielectric characteristics. This resin composition comprises: a curable resin containing a cyclic olefin monomer unit; and an azo-based compound.

Description

Resin composition, method for curing the same, and cured product

[0001] The present invention relates to a resin composition, a method for curing the same, and a cured product thereof.

[0002] As communication frequencies move into the gigahertz and higher frequency ranges, there is an increasing need for multilayer substrates made of insulating materials with low dielectric properties, such as copper clad laminates (CCLs), flexible copper clad laminates (FCCLs), and resin-coated copper (RCCs). Therefore, hydrocarbon-based resins, which inherently possess low dielectric properties, have attracted attention. In particular, curable cyclic olefin (co)polymers with high glass transition temperatures (Tg) and low dielectric properties have been proposed as insulating materials (Patent Documents 1, 2, and 3). Patent Documents 4, 5, and 6 disclose ethylene-olefin (aromatic vinyl compound)-aromatic polyene copolymers with specific compositions and formulations obtained from specific coordination polymerization catalysts. This technology selectively copolymerizes only one of the two vinyl groups of the aromatic polyene (divinylbenzene), preserving the remaining vinyl group, thereby easily producing crosslinkable hydrocarbon-based copolymer macromonomers with aromatic vinyl functional groups.

[0003] International Publication No. WO 2012 / 046443 JP 2023-007603 A JP 2018-039995 A JP 2009-161743 A International Publication No. WO 2021 / 112087 International Publication No. WO 2021 / 112088

[0004] However, even conventional curable hydrocarbon-based resins are required to have even higher levels of low dielectric properties. Therefore, in one embodiment, the present invention aims to provide a resin composition with excellent low dielectric properties. In another embodiment, the present invention aims to provide a cured product of such a resin composition and a method for producing the same.

[0005] In view of the above-mentioned problems, one embodiment of the present invention is a resin composition including a curable resin containing a cyclic olefin monomer unit as a hydrocarbon-based resin and an azo-based initiator. Another embodiment of the present invention is a cured product of such a resin composition and a method for producing the same.

[0006] That is, the present invention can provide the following aspects. [Aspect 1] A resin composition comprising a curable resin containing cyclic olefin monomer units and an azo compound. [Aspect 2] The composition according to Aspect 1, wherein the curable resin further comprises aromatic polyene monomer units and aromatic vinyl units. [Aspect 3] The composition according to Aspect 2, wherein the curable resin has an aromatic vinyl group as a functional group. [Aspect 4] The composition according to Aspect 1, wherein the curable resin is an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer. [Aspect 5] The composition according to Aspect 4, comprising an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following (1) to (6): (1) The number average molecular weight is 500 or more and 30,000 or less. (2) The α-olefin units are α-olefins having 2 to 20 carbon atoms. (3) The aromatic vinyl compound units are aromatic vinyl compounds having 8 to 20 carbon atoms. (4) The cyclic olefin units are cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 10% by mass or more but less than 99% by mass. (5) The aromatic polyene units are one or more selected from polyenes having 5 to 20 carbon atoms and each 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 units contained in the copolymer is 2 or more per number-average molecular weight, and the number-average molecular weight per vinyl group and / or vinylene group derived from the aromatic polyene monomer units is 250 to 10,000. (6) The total content (mass %) of the α-olefin, cyclic olefin, aromatic vinyl compound, and aromatic polyene monomer units is 100% by mass. [Aspect 6] A method for producing a cured product using the resin composition according to any one of Aspects 1 to 5. [Aspect 7] The production method according to Aspect 6, comprising using 0.01 to 5 parts by mass of an azo-based curing agent per 100 parts by mass of the curable resin. [Aspect 8] The manufacturing method according to Aspect 6, wherein the curing is carried out at a temperature of 100°C to 250°C for 3 minutes or more and 180 minutes or less. [Aspect 9] A cured product of the resin composition according to any one of Aspects 1 to 5. [Aspect 10] The cured product according to Aspect 9, having a dielectric constant of less than 2.5 and a dielectric loss tangent of 0.0005 or less, measured at 23°C and 40 GHz.

[0007] According to one embodiment of the present invention, a resin composition having excellent low dielectric properties can be provided. According to another embodiment of the present invention, a cured product of such a resin composition and a method for producing the same can be provided.

[0008] Next, embodiments of the present invention will be described in detail. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes and improvements may be made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0009] In this specification, the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer includes a cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer. In this specification, the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer may be simply referred to as the copolymer of the present invention, or simply as the copolymer. Unless otherwise specified, the numerical ranges in this specification include the upper and lower limits. In this specification, the term sheet also encompasses the concept of film. Furthermore, even when the term film is used in this specification, it is intended to have the same meaning as sheet. Furthermore, even when the term film is used in this specification, it is intended to encompass the concept of sheet.

[0010] In one embodiment of the present invention, there is provided a resin composition comprising a curable resin containing at least a cyclic olefin monomer unit (which refers to a monomer that is the basis of the olefin monomer unit in a copolymer, but in this specification, the terms "monomer" and "monomer unit" (or "unit") may be used interchangeably depending on the context. The same applies to similar terms hereinafter), and an azo-based compound. Furthermore, there is provided a method for curing the resin composition, and further provided is a cured product obtained.

[0011] <Curable Resin Containing Cyclic Olefin Monomer Units> The curable resin containing cyclic olefin monomer units used in the present invention may be a known curable resin containing cyclic olefin monomer units. For example, the cyclic olefin monomer units are cyclic olefins having 5 to 30 carbon atoms, such as norbornene, butylnorbornene, phenylethylnorbornene, dimethanooctahydronaphthalene (DMON), trimethanododecahydroanthracene (TMDA), indanylnorbornene (1,4-methano-1,9a,4,4a-tetrahydrofluorene), methylphenylnorbornene (MPNB, 5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene), and acenaphthylene. Examples of curable monomer units include 5-vinyl-2-norbornene, 8-vinyl-9-methyltetracyclo-3-dodecene, butenylnorbornene, and hexenylnorbornene. Curable resins containing such cyclic olefin monomer units are described, for example, in WO 2012 / 046443, JP 2020-105328 A, JP 2023-7603 A, and JP 2018-39995 A.

[0012] The present invention further relates to a curable resin in which the cured resin contains an aromatic polyene monomer unit. Divinylbenzene is preferred as the aromatic polyene monomer unit. Furthermore, an aromatic vinyl group is preferred as the functional group in the curable resin. Examples of such curable resins include those disclosed in International Publication No. 2021 / 112087, International Publication No. 2022 / 014599, JP 2018-39995 A, and Japanese Patent No. 7440684.

[0013] The curable resin preferably used in the present invention is an α-olefin-cyclic olefin-aromatic polyene copolymer or an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer. In this specification, the copolymer may also be referred to as a "resin."

[0014] More preferably, the curable resin is an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following (1) to (6): (1) the number average molecular weight is 500 or more and 100,000 or less; (2) the α-olefin units are α-olefins having 2 to 20 carbon atoms; (3) the aromatic vinyl compound units are aromatic vinyl compounds having 8 to 20 carbon atoms; (4) the cyclic olefin units are cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 10% by mass or more and less than 99% by mass; and (5) the aromatic polyene units are one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl groups and / or vinylene groups in the molecule, the content of vinyl groups and / or vinylene groups derived from the aromatic polyene units contained in the copolymer is 2 or more per number average molecular weight, and the number average molecular weight per vinyl group and / or vinylene group derived from the aromatic polyene monomer units is 250 or more and 10,000 or less. (6) The total content (mass %) of each monomer unit of an α-olefin, a cyclic olefin, an aromatic vinyl compound, and an aromatic polyene is 100 mass %.

[0015] The α-olefin-cyclic olefin-aromatic polyene copolymer of this embodiment can be obtained by copolymerizing the α-olefin, cyclic olefin, and aromatic polyene monomers.

[0016] The α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer of this embodiment can be obtained by copolymerizing the respective monomers of α-olefin, cyclic olefin, aromatic vinyl compound, and aromatic polyene.

[0017] The α-olefin monomer is an α-olefin having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene, with ethylene being the most preferred. The α-olefin content in the copolymer is arbitrary, but is preferably 0% by mass or more and 40% by mass or less, more preferably more than 0% by mass or more and 30% by mass or less, even more 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 α-olefin monomer unit content is 40% by mass or less, the content of cyclic olefin units becomes relatively high, allowing the glass transition temperature of the copolymer to fall within a preferred range. The higher the α-olefin monomer unit content (e.g., 5% by mass or more), the less brittle the copolymer and its cured product become.

[0018] As used herein, the term "cyclic olefin monomer" refers to a cyclic olefin having 7 to 30 carbon atoms. Cyclic olefins having 7 to 30 carbon atoms are cyclic olefins having one or more alicyclic structures in the molecule and a polymerizable vinyl group, vinylene group, or vinylidene group. Preferred cyclic olefins are cyclic olefins having a hydrocarbon ring structure without heteroatoms, and more preferred are cyclic olefins having an unsaturated hydrocarbon ring. While such cyclic olefins are characterized by low dielectric properties and high glass transition temperatures, they also have the notable advantage of being easily prepared using inexpensive raw materials and simple processes compared to conventional engineering plastics.

[0019] Examples of such cyclic olefins include norbornenes and acenaphthylene. Norbornenes are monomers selected from norbornene and substituted norbornenes. Norbornene can be synthesized, for example, by the Diels-Alder reaction of ethylene and cyclopentadiene. Substituted norbornenes are substituted norbornenes having a polymerizable vinyl group, vinylene group, or vinylidene group in the molecule, and examples include dimethanooctahydronaphthalene (DMON) and trimethanododecahydroanthracene (TMDA). These are also Diels-Alder reaction products of norbornenes and cyclopentadiene. These substituted norbornenes are specifically described, for example, in International Publication No. WO 2006 / 118261. In the present invention, more preferred cyclic olefins are those having a larger number of ring structures and a higher molecular weight, such as dimethanooctahydronaphthalene (DMON) or trimethanododecahydroanthracene (TMDA). Copolymerization of such cyclic olefins allows for the production of copolymers with a higher glass transition temperature (Tg) at a lower mol% content of the monomer units. This allows for the copolymer to have a higher glass transition temperature while maintaining its high glass transition temperature. Increasing the mol% content of aromatic vinyl compound monomer units as other monomer units enhances the aromatic properties of the copolymer as a whole, which is preferable because it improves the copolymer's compatibility with other raw materials and resins. These high molecular weight cyclic olefins may be used alone or in a mixture with norbornene or the like for copolymerization.

[0020] In particular, when the above-mentioned DMON or TMDA is produced by the Diels-Alder reaction, it may be obtained as a mixture with norbornene, and by using the mixture as it is for polymerization, it is possible to reduce the production cost. Furthermore, in the present invention, more preferred cyclic olefins are norbornenes having an aromatic substituent, and examples thereof include phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), which is a Diels-Alder reaction product of cyclopentadiene and styrene, indanylnorbornene (1,4-methano-1,9a,4,4a-tetrahydrofluorene), which is a Diels-Alder reaction product of cyclopentadiene and indene, and methylphenylnorbornene (MPNB, 5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene), which is a Diels-Alder reaction product of cyclopentadiene and α-methylstyrene. When copolymerized, norbornenes having such aromatic substituents can impart a higher glass transition temperature (Tg) to the copolymer, and furthermore, because they exhibit aromaticity, they can exhibit high compatibility with other aromatic raw materials (crosslinkable soft resins and flame retardants). Furthermore, the use of methylphenylnorbornene (5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene) is preferable because it can improve the thermal oxidation resistance of the resulting copolymer, as described in JP-A-2005-239975. Norbornenes having these aromatic substituents are specifically described, for example, in JP-A-11-504669 and JP-A-2005-239975.

[0021] The content of the cyclic olefin monomer units contained in the copolymer is arbitrary, but may be, for example, 10% by mass or more and less than 99% by mass. When a high glass transition temperature (Tg) of the copolymer is desired, the optimal content of the cyclic olefin monomer units contained in the copolymer varies depending on the type of cyclic olefin, but is, for example, 50% by mass or more and less than 99% by mass, preferably 50% by mass or more and less than 95% by mass, more preferably 70% by mass or more and less than 95% by mass, and most preferably 80% by mass or more and less than 95% by mass. The higher the content of the cyclic olefin monomer units, the higher the Tg of the copolymer. From the viewpoint of imparting a certain degree of toughness to the copolymer, the optimal content of the cyclic olefin monomer units contained in the copolymer may be less than 90% by mass. A content within these ranges makes it easier 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 less than 350°C, more preferably 130°C or more and less than 300°C, and most preferably 180°C or more and less than 300°C. On the other hand, when the content of the cyclic olefin monomer units is in the range of 10% by mass or more but less than 50% by mass, a copolymer with a relatively low Tg is obtained. In particular, for copolymers that are soft at room temperature, the content of the cyclic olefin monomer units is in the range of 10% by mass or more but less than 40% by mass. Those skilled in the art can appropriately adjust the type and content of the cyclic olefin monomer units used to achieve this preferred glass transition temperature. Furthermore, the higher the content of the cyclic olefin monomer units contained in the copolymer, the more improved the low dielectric properties of the copolymer itself, its composition, or its cured product. Specifically, the higher the content of the cyclic olefin monomer units contained in the copolymer, the lower the dielectric tangent value of the copolymer itself, its composition, or its cured product, which is preferable.

[0022] In a preferred embodiment, the cyclic olefin monomer units contained in the copolymer may include monomer units derived from one or more selected from the group consisting of norbornene, methylphenylnorbornene, substituted norbornenes other than methylphenylnorbornene, and dimethanooctahydronaphthalene, and more preferably, may include monomer units derived from one or more selected from the group consisting of norbornene, methylphenylnorbornene, and dimethanooctahydronaphthalene.

[0023] The aromatic vinyl compound monomer is an aromatic vinyl compound having from 8 to 20 carbon atoms, and examples thereof include styrene, paramethylstyrene, ethylvinylbenzene, paraisobutylstyrene, various vinylnaphthalenes, and various vinylanthracenes. Monomer units derived from aromatic vinyl compounds may be contained in the copolymer as a result of copolymerization of aromatic vinyl compound components contained as impurities in the aromatic polyene used in polymerization. The content of aromatic vinyl compound monomer units contained in the copolymer is arbitrary, but is preferably from 0.1% by mass to 70% by mass, more preferably from 1% by mass to 60% by mass. The aromatic vinyl compound monomer of this embodiment has at least one vinyl group or vinylene group in the molecule.

[0024] When the content of aromatic vinyl compound monomer units is 40% by mass or less, the content of cyclic olefin units becomes relatively high, making it possible to increase the glass transition temperature of the copolymer. On the other hand, when the content of aromatic vinyl compound monomer units is 10% by mass or more, preferably 30% by mass or more, it is possible to improve the aromaticity of the copolymer, particularly when the cyclic olefin of the copolymer of the present invention does not have an aromatic substituent, and this improves compatibility with other resin materials, flame retardants, and fillers, suppresses bleed-out of flame retardants, and facilitates high filler loading, which is preferable. As described above, the glass transition temperature and aromaticity of the copolymer can be adjusted by the aromatic vinyl compound content of the copolymer.

[0025] The aromatic polyene monomer is a polyene having 5 to 20 carbon atoms and containing multiple vinyl groups and / or vinylene groups in its molecule, preferably a polyene having 8 to 20 carbon atoms. The aromatic polyene monomer is preferably a polyene having 8 to 20 carbon atoms and containing multiple vinyl groups in its molecule, more preferably various ortho-, meta-, and para-divinylbenzenes or mixtures thereof, divinylnaphthalene, divinylanthracene, p-2-propenylstyrene, p-3-butenylstyrene, or other compounds having an aromatic vinyl structure and consisting essentially of carbon and hydrogen and substantially free of oxygen, nitrogen, and halogens. Furthermore, bifunctional aromatic vinyl compounds such as 1,2-bis(vinylphenyl)ethane (abbreviation: BVPE), as described in JP-A-2004-087639, can also be used. Among these, various ortho-, meta-, and para-divinylbenzenes or mixtures thereof are preferably used, and a mixture of meta- and para-divinylbenzene is most preferably used. In this specification, these divinylbenzenes are referred to as divinylbenzenes. When a divinylbenzene is used as the aromatic polyene, the vinyl group contained in the divinylbenzene unit is preferred because it has high crosslinking efficiency during curing treatment and facilitates curing.

[0026] The number-average molecular weight of the copolymer of the present invention is preferably 500 to 100,000, more preferably 500 to 30,000, even more preferably 500 to 15,000, and even more preferably 500 to 12,000. A number-average molecular weight of 500 or more improves the mechanical properties of the composition in the uncured state and provides moderate adhesion, thereby facilitating molding and processing as a thermoplastic resin. A number-average molecular weight of 30,000 or less improves molding processability. Furthermore, a number-average molecular weight of 30,000 or less, or 12,000 or less, is particularly advantageous because it allows the viscosity of a varnish containing the copolymer to be kept below a certain value. A varnish viscosity lower than a certain value improves workability and facilitates impregnation of glass fibers and the like with the varnish, improving embeddability in semiconductor devices with uneven surfaces.

[0027] In the copolymer of the present invention, the content of vinyl groups and / or vinylene groups derived from aromatic polyene monomer units may be 2 to 30, preferably 3 to 20, per number-average molecular weight. The content of vinyl groups and / or vinylene groups derived from aromatic polyene monomer units may be less than 30, preferably less than 20, per number-average molecular weight. The content of vinyl groups and / or vinylene groups may be collectively referred to as the "vinyl group content" below. Because vinyl groups are superior to vinylene groups in terms of crosslinking efficiency, in the present invention, the content of vinyl groups (excluding vinylene groups in this case) derived from aromatic polyene monomer units is preferably 2 to 30, preferably 3 to 20, per number-average molecular weight. A vinyl group content of 2 or more results in high crosslinking efficiency and a cured product with sufficient crosslink density. Increasing the vinyl group content facilitates improving the mechanical properties of the final cured product at room temperature and high temperatures. The vinyl group content derived from aromatic polyene monomer units (divinylbenzene monomer units) per number average molecular weight in the copolymer is determined by the ratio of the number average molecular weight (Mn) calculated in terms of standard polystyrene obtained by a GPC (gel permeation chromatography) method known to those skilled in the art to ... 1 H-NMR measurement and / or quantitative mode 13 This can be obtained by comparing the composition obtained by C-NMR measurement with the vinyl group content derived from the aromatic polyene monomer units. Such a method is obvious and well known to those skilled in the art. It is also possible to use the methods described in the patent documents in the prior art literature of this specification. The content of aromatic polyene monomer units in the copolymer of the present invention is arbitrary, but is 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, resulting in improved stability during copolymer production and curing.

[0028] In one embodiment of the copolymer of the present invention, the α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer specifically includes at least one member selected from the group consisting of ethylene-norbornene-styrene-divinylbenzene copolymer, propylene-norbornene-styrene-divinylbenzene copolymer, 1-hexene-norbornene-styrene-divinylbenzene copolymer, 1-octene-norbornene-styrene-divinylbenzene copolymer, ethylene-norbornene-ethylvinylbenzene-divinylbenzene copolymer, propylene-styrene-norbornene-divinylbenzene copolymer, 1-hexenestyrene-styrene-norbornene-divinylbenzene copolymer, and 1-octene-norbornene-styrene-divinylbenzene copolymer. Furthermore, copolymers in which the above-mentioned norbornene is replaced with dimethanooctahydronaphthalene (DMON), trimethanododecahydroanthracene (TMDA), phenylnorbornene (5-phenylbicyclo[2.2.1]hept-2-ene), or methylphenylnorbornene (5-methyl-5-phenylbicyclo[2.2.1]hept-2-ene) are also suitable examples of copolymers of the present invention.

[0029] In an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer according to a certain embodiment, an embodiment in which the content of α-olefin monomer units is 0% by mass (i.e., no α-olefin monomer units are included) can also be provided. Such a copolymer is also referred to herein as a "cyclic olefin-aromatic polyene copolymer" or a "cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer." The copolymer according to this embodiment will be described below. Here, the types of the cyclic olefin, aromatic vinyl compound, and aromatic polyene monomers, and the contents of each monomer unit in the copolymer are as described above.

[0030] <Azo Compound> The resin composition of the present invention contains a curable resin containing at least the cyclic olefin monomer unit and an azo compound. The azo compound is a compound that decomposes into radicals and nitrogen molecules when exposed to heat or light, and such known azo compounds can be used. Azo compounds that do not contain a nitrile group (-CN) in their molecular structure are preferred, azo compounds that do not contain a nitrile group (-CN) or oxygen atoms in their molecular structure are more preferred, and azo compounds whose structure other than the azo group consists of carbon and hydrogen atoms are most preferred. The use of such azo compounds can improve the low dielectric properties of the resulting cured product. In other words, the dielectric loss tangent of the resulting cured product can be lowered compared to when other curing agents are used. Such azo compounds are available, for example, from Fujifilm Corporation. Examples of preferred azo compounds include VR-110, VR-65, and VR-59.

[0031] There are no particular restrictions on the amount of azo compounds used, but generally, an amount of 0.01 to 5 parts by mass, and particularly 0.1 to 1 part by mass, is preferred relative to 100 parts by mass of the curable resin containing cyclic olefin monomer units. When an azo compound is used as a curing agent, the curing treatment is carried out at an appropriate temperature and time, taking into account its half-life. In this case, the conditions are optional depending on the curing agent, but generally, a temperature range of about 50°C to 200°C is appropriate.

[0032] <Compositions Comprising the Copolymer of the Present Invention> The copolymer of the present invention can be cured alone, but it may also be combined with other materials to form a composition, and the composition can be cured. Here, the other materials include the following "resin component," "monomer," "other olefin-aromatic vinyl compound-aromatic polyene copolymer not containing a cyclic olefin," "solvent," "filler," "other additives," etc.

[0033] <Resin Component> Any resin component can be used as long as it does not impair the effects of the present invention. Preferably, one or more resin components selected from hydrocarbon-based elastomers, polyether-based resins, aromatic polyene-based resins, and olefin-aromatic vinyl compound-aromatic polyene copolymers containing no cyclic olefin monomer units are used. Of these, hydrocarbon-based elastomers and olefin-aromatic vinyl compound-aromatic polyene copolymers containing no cyclic olefin are more preferred. Among hydrocarbon-based elastomers, conjugated diene polymers are preferred. Among conjugated diene polymers, 1,2-polybutadiene is preferred. The amount of these resin components is arbitrary, but is preferably a total of 100 parts by mass or less, and more preferably 50 parts by mass or less, based on 100 parts by mass of the composition of the present invention. If the amount of these resin components added is large, the dielectric constant and dielectric loss tangent of the final cured product may become high.

[0034] <Hydrocarbon Elastomer> Hydrocarbon elastomers suitable for use in the composition of the present invention may have a number-average molecular weight of 20,000 or more, preferably 30,000 or more. Examples of hydrocarbon elastomers include one or more elastomers selected from ethylene-based or propylene-based elastomers, conjugated diene polymers, block or random copolymers of aromatic vinyl compounds and conjugated dienes, and hydrogenated products thereof. Examples of ethylene-based elastomers include ethylene-α-olefin copolymers such as ethylene-octene copolymers and ethylene-1-hexene copolymers, EPR, and EPDM. Examples of propylene-based elastomers include atactic polypropylene, low stereoregular polypropylene, and propylene-α-olefin copolymers such as propylene-1-butene copolymer. These hydrocarbon elastomers may be modified, for example, by introducing functional groups with maleic anhydride or other compounds.

[0035] <Conjugated Diene Polymer> Examples of conjugated diene polymers include polybutadiene and 1,2-polybutadiene. Examples of aromatic vinyl compound-conjugated diene block or random copolymers and their hydrogenated products (hydrogenated products) include SBS, SIS, SEBS, SEPS, SEEPS, and SEEBS. Suitable 1,2-polybutadiene is available, for example, as a product from JSR Corporation, and also available from Nippon Soda Co., Ltd. under the product names of liquid polybutadiene B-1000, 2000, and 3000. Another suitable copolymer containing a 1,2-polybutadiene structure is "Ricon 100" from TOTAL CRAY VALLEY. These conjugated diene polymers and hydrogenated products thereof may be modified, for example, by introducing functional groups with maleic anhydride or other compounds. Among the conjugated diene polymers, conjugated diene copolymers are preferred. Among these conjugated diene copolymers, hydrogenated block copolymers such as SEBS, SEPS, SEEPS, and SEEBS are useful as compatibilizers for the copolymer of the present invention and other resin components. These are available from Asahi Kasei under the trade names Tuftec or SOE-SS, from Kuraray Co., Ltd. under the trade name Septon, and from KRATON under the trade name Kraton.

[0036] <Polyether-Based Resin> Examples of polyether-based resins include polyphenylene ether and polyether. Polyphenylene ethers having functional groups are preferably those in which the molecular terminals are modified with functional groups. Furthermore, when added for the purpose of curing the composition of the present invention, it is preferable that the polyphenylene ether has multiple functional groups in one molecule. For example, modified polyphenylene ether is preferable. Examples of functional groups include radically polymerizable functional groups and epoxy groups, and preferably radically polymerizable functional groups. A vinyl group is preferable as the radically polymerizable functional group. As the vinyl group, one or more of the group consisting of an allyl group, a (meth)acryloyl group, and an aromatic vinyl group are preferable, one or more of the group consisting of a (meth)acryloyl group and an aromatic vinyl group are more preferable, and an aromatic vinyl group is most preferable. In other words, in the composition of the present invention, a bifunctional polyphenylene ether in which both molecular chain terminals are modified with radically polymerizable functional groups is particularly preferable. Examples of such polyphenylene ethers include Noryl (trademark) SA9000 manufactured by SABIC (modified polyphenylene ether having methacryloyl groups at both ends, number average molecular weight 2200) and bifunctional polyphenylene ether oligomer manufactured by Mitsubishi Gas Chemical Company, Inc. (OPE-2St, modified polyphenylene ether having vinylbenzyl groups at both ends, number average molecular weight 1200). Also usable are allylated PPE manufactured by Asahi Kasei Corporation and aromatic polyethers (ELPAC HC-F series) manufactured by JSR Corporation. Of these, the bifunctional polyphenylene ether oligomer (OPE-2St) manufactured by Mitsubishi Gas Chemical Company, Inc. and aromatic polyethers (ELPAC HC-F series) manufactured by JSR Corporation are preferred.

[0037] <Aromatic Polyene Resin> Aromatic polyene resins include divinylbenzene-based reactive hyperbranched copolymers (PDV or ODV) manufactured by Nippon Steel Chemical & Material Co., Ltd. Such copolymers are described, for example, in the literature "Synthesis of Polyfunctional Aromatic Vinyl Copolymers and Development of Novel IPN-Type Low Dielectric Loss Materials Using the Same" (Kawabe Masanao et al., Journal of the Japan Institute of Electronics Packaging, p. 125, Vol. 12, No. 2 (2009)). The aromatic polyene resin of this embodiment is preferably a resin (copolymer) substantially composed of aromatic polyene monomer units and aromatic monovinyl compound monomer units, and more preferably, the aromatic polyene resin does not contain olefin monomer units. The aromatic polyene resin of this embodiment is preferably a resin obtained by cationic polymerization or anionic polymerization. These can be used alone or in any combination of two or more.

[0038] <Monomer> The composition of the present invention may contain any amount of monomers, but the total amount of these monomers is preferably 50 parts by mass or less, and more preferably 20 parts by mass or less, based on 100 parts by mass of the composition of the present invention. The composition may be substantially free of monomers. Monomers that can be suitably used in the composition of the present invention preferably have a molecular weight of less than 1,000, more preferably less than 500. Monomers that can be suitably used in the composition of the present invention include the aromatic vinyl compound monomers described above, the aromatic polyene monomers described above, the aromatic vinylene monomers described below, and / or the polar monomers described below. The monomers are preferably monomers that can be polymerized with a radical polymerization initiator, and more preferably one or more of the group consisting of aromatic vinyl compounds and aromatic polyenes. Furthermore, BVPE (1,2-bis(vinylphenyl)ethane) described in JP-A-2003-212941 can also be suitably used.

[0039] <Aromatic Vinylene Monomer> The aromatic vinylene monomer that may be included in the present invention refers to a compound having both a single aromatic ring or multiple condensed aromatic rings having 9 to 30 carbon atoms and a vinylene group. Examples of such aromatic vinylene compounds include indenes, beta-substituted styrenes, acenaphthylenes, etc. Examples of indenes include indene, various alkyl-substituted indenes, and phenyl-substituted indenes. Examples of beta-substituted styrenes include beta-alkyl-substituted styrenes such as beta-methylstyrene, and phenyl-substituted styrenes. Examples of acenaphthylenes include acenaphthylene, various alkyl-substituted acenaphthylenes, and various phenyl-substituted acenaphthylenes. As the aromatic vinylene compound, the above-exemplified compounds may be used alone or in combination of two or more. From the viewpoints of industrial availability and radical polymerizability, acenaphthylene is the most preferred aromatic vinylene compound.

[0040] <Polar Monomer> For the purpose of imparting adhesion to other materials required as an insulating material, a relatively small amount of polar monomer can be used, for example, 10 parts by mass or less per 100 parts by mass of an olefin-aromatic vinyl compound-aromatic polyene copolymer. Addition of a larger amount may result in the dielectric constant and dielectric dissipation factor of the final cured product being higher than desired. Examples of the polar monomer include various maleimides, bismaleimides, maleic anhydride, glycidyl (meth)acrylate, triallyl isocyanurate, tri(meth)acrylic isocyanurate, trimethylolpropane tri(meth)acrylate, etc. Maleimides and bismaleimides usable in the present invention are described, for example, in International Publication No. 2016 / 114287 and can be purchased, for example, from Daiwa Kasei Co., Ltd. These maleimide group-containing compounds may be used as polyaminobismaleimide compounds from the viewpoints of solubility in organic solvents, high-frequency characteristics, high adhesion to conductors, and prepreg moldability. Polyaminobismaleimide compounds can be obtained, for example, by subjecting a compound having two maleimide groups at its terminals to a Michael addition reaction with an aromatic diamine compound having two primary amino groups in the molecule. When attempting to obtain high crosslinking efficiency with a small amount of addition, it is preferable to use a polar monomer having a multifunctional group (bifunctional or higher), such as bismaleimides, triallyl isocyanurate (TAIC), or trimethylolpropane tri(meth)acrylate.

[0041] <Solvent> An appropriate solvent may be added to the composition of the present invention as needed. The solvent is used to adjust the viscosity and fluidity of the composition, particularly the varnish. Volatile solvents are preferred, such as cyclohexane, toluene, ethylbenzene, acetone, and isopropanol. The solvent is used to adjust the viscosity and fluidity of the composition as a varnish. A solvent with a high boiling point at atmospheric pressure, i.e., low volatility, results in a uniform thickness of the applied film, so a solvent with a boiling point of at least a certain level is preferred. A preferred boiling point is 100°C or higher, more preferably 130°C or higher and 300°C or lower, at atmospheric pressure. Solvents suitable for such varnishes include cyclohexane, toluene, xylene, mesitylene, tetralin, acetone, ethylbenzene, limonene, mixed alkanes, mixed aromatic solvents, ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether. In the case of a solvent, the amount used is preferably in the range of 10 to 2,000 parts by mass, more preferably 5 to 500 parts by mass, and even more preferably 10 to 300 parts by mass, per 100 parts by mass of the composition of the present invention. The solvent is generally substantially removed from the composition by a drying treatment or the like before the composition is cured.

[0042] <Filler> The composition of this embodiment may contain a conventionally known organic filler, if necessary. Either an inorganic filler or an organic filler can be used as the filler, and the type is not particularly limited. These fillers can be added for purposes such as controlling the coefficient of thermal expansion, controlling thermal conductivity, and reducing cost. The amount added may be appropriately set as needed and is not particularly limited. The maximum amount that can be added is preferably 1,000 parts by mass or less per 100 parts by mass of the composition. In particular, when adding an inorganic filler, it is preferable to use a known surface modifier, such as a silane coupling agent. In particular, when the objective of the present invention is to achieve a composition with a low dielectric constant and low dielectric loss, silica (e.g., low-dielectric fused silica or deflagration silica) or boron nitride (BN) is preferred as the inorganic filler. From the perspective of low dielectric properties, adding a large amount will result in a particularly high dielectric constant. Therefore, preferably, less than 500 parts by mass, more preferably less than 400 parts by mass, and even more preferably 100 parts by mass or less of the filler per 100 parts by mass of the copolymer may be used. Furthermore, in order to improve and enhance low dielectric properties (low dielectric constant, low dielectric loss tangent), hollow fillers or fillers having a shape with many voids may be added. These may be used alone or in any combination of two or more.

[0043] Furthermore, instead of inorganic fillers, organic fillers such as high molecular weight polyethylene, ultra-high molecular weight polyethylene, polystyrene, styrene-divinylbenzene copolymer, or fluorine-based resins can also be used. Examples of fluorine-based resins include known fluorine-containing resins such as PTFE (polytetrafluoroethylene) and PFA (perfluoroalkoxyalkane). An example of such a resin is Fluon+ (registered trademark) EA-2000 from AGC. When the melting point or glass transition temperature of the organic filler is lower than the solder reflow temperature of 290°C, it is preferable from the standpoint of heat resistance that the organic filler itself be crosslinked, and it is preferable that it be blended in the form of fine particles or powder. These organic fillers can also suppress increases in dielectric constant and dielectric loss tangent.

[0044] On the other hand, by mixing and dispersing a high-dielectric-constant insulating filler having a dielectric constant at 1 GHz of preferably 3 to 10,000, more preferably 5 to 10,000, into the composition of the present invention, it is possible to produce a cured insulating product having a high-dielectric-constant insulating layer with a dielectric constant of preferably 2.5 to 20, more preferably 2.8 to 10, while suppressing an increase in dielectric dissipation factor (dielectric loss). Increasing the dielectric constant of a film made from the cured insulating product enables the miniaturization of circuits and the increase in capacitance of capacitors, contributing to the miniaturization of high-frequency electrical components. High-dielectric-constant, low-dielectric-dissipation factor insulating layers are suitable for applications such as capacitors, inductors for resonant circuits, filters, and antennas. Examples of high-dielectric-constant insulating fillers used in the present invention include inorganic fillers or metal particles that have been subjected to an insulating treatment. Specific examples include known high-dielectric-constant inorganic fillers such as barium titanate and strontium titanate. Other examples are specifically described in, for example, JP 2004-087639 A.

[0045] <Other Additives> The composition of the present invention may further contain one or more additives selected from a flame retardant and a surface modifier. The composition of the present invention can serve as a matrix for a cured body, and when cured, it has excellent filling properties for other materials. Therefore, the composition contains one or more additives selected from these fillers, flame retardants, and surface modifiers, and the cured body tends to exhibit impact resistance and toughness even after curing.

[0046] <Flame Retardant> A known flame retardant can be used in the composition of the present invention. Preferred flame retardants are known organic phosphorus-based flame retardants such as phosphate esters or condensates thereof, known bromine-based flame retardants, and red phosphorus, from the viewpoint of maintaining a low dielectric constant and a low dielectric loss tangent. Among phosphate esters, compounds having multiple xylenyl groups in the molecule are particularly preferred from the viewpoint of flame retardancy and a low dielectric loss tangent.

[0047] In addition to the flame retardant, antimony compounds such as antimony trioxide, antimony tetraoxide, antimony pentoxide, and sodium antimonate, or nitrogen-containing compounds such as melamine, triallyl-1,3,5-triazine-2,3,4-(1H,3H,5H)-trione, and 2,4,6-triaryloxy-1,3,5-triazine may be added as a flame retardant aid. The total amount of these flame retardants and flame retardant aids is preferably 1 to 100 parts by mass relative to 100 parts by mass of the composition.

[0048] <Surface Modifier> The composition of the present invention may contain various surface modifiers for the purpose of improving adhesion to fillers, copper plates, and wiring. The amount of the surface modifier used per 100 parts by mass of the composition of the present invention other than the surface modifier is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass. Examples of the surface modifier include various silane coupling agents and titanate coupling agents. Various silane coupling agents and titanate coupling agents may be used singly or in combination.

[0049] In the present invention, the fluidity of the composition can be adjusted by changing the compounding ratio of the "resin component," "monomer," "solvent," "filler," or "other additives." Specifically, the composition of the present invention can be in the form of a "thermoplastic composition," a "semi-cured state (such as a B-stage sheet)," or a "varnish."

[0050] The composition of the present invention can be obtained by mixing, dissolving, or melting one or more of "resin components," "monomers," "solvents," "fillers," and "other additives," and can further contain general additives that are added to ordinary resins, such as lubricants, stabilizers, antioxidants, weather resistance agents, and ultraviolet absorbers, to the extent that the object of the present invention is not impaired. Any known method can be used for mixing, dissolving, or melting these.

[0051] <Thermoplastic resin composition and molded article thereof> The composition of the present invention uses a copolymer having a certain molecular weight or more, and further contains the specified resin components, and can exhibit the properties of a thermoplastic resin. Therefore, under conditions that do not cause crosslinking, the composition can be molded into shapes such as sheets, tubes, strips, pellets, etc. in a substantially uncured state by a known molding method for thermoplastic resins. The molded article may be crosslinked (cured) after or during molding.

[0052] The composition of the present invention may be provided as a sheet obtained by molding the composition, heated and melted at a temperature below or equal to the curing agent's working temperature or decomposition temperature, using a known method. Forming into a sheet may be achieved by T-die extrusion, two-roll extrusion, or extrusion lamination onto a substrate film. In this case, the composition's composition, copolymer / monomer mass ratio, or solvent, resin component, and flame retardant are selected and adjusted so that the composition melts below or equal to the curing agent's working temperature or decomposition temperature and becomes solid at or near room temperature. In this case, the sheet is substantially uncured. After various processing and assembly steps, the sheet is finally treated at a temperature and time above the curing agent's working temperature or decomposition temperature to achieve complete curing. This method is a common technique used for ethylene-vinyl acetate resin-based crosslinked sealant sheets for solar cells (photovoltaic power generation devices).

[0053] <Molded Article in a Semi-Cured State (B-Stage Sheet, etc.)> The composition of the present invention can also be formed into a molded article, such as a sheet or tube, in a partially crosslinked state, for example, a state in which a portion of the curing agent contained therein has reacted and been semi-cured (so-called B-stage state). Here, the semi-cured state is defined as a state in which the proportion of gel content as a resin component in the composition of the present invention is more than 20% by mass and not more than 80% by mass, independently of the definition of the uncured state. The gel content is a value obtained by measurement in accordance with JIS K6796:1998. For example, by employing multiple curing agents and / or curing conditions with different curing temperatures, the composition can be semi-cured, and the melt viscosity and fluidity can be controlled to achieve a B-stage state. That is, the curable resin or composition can be molded into an easily handleable B-stage sheet by a first curing step (partial curing), which can then be laminated and pressure-bonded to an electronic device or substrate, followed by a second curing step (complete curing) to form the final shape. In this case, the composition, i.e., the copolymer / monomer mass ratio, is selected, and if necessary, a solvent, resin component, and flame retardant are added. The composition further contains a curing agent such as a peroxide, which is partially cured and adjusted to a sheet shape (B-stage state). After molding and assembling the device, the composition can be heated under pressure to fully cure. Known methods can be used to partially cure the composition. For example, peroxides with different decomposition temperatures are used in combination, and the mixture is treated for a predetermined time at a temperature at which only one of the peroxides is substantially active to obtain a semi-cured sheet. Finally, the mixture is treated for a sufficient time at a temperature at which all of the curing agents are active to fully cure the sheet.

[0054] Furthermore, the molded article may be a sheet. The sheet may be uncured (semi-cured) to the extent that it can maintain its sheet shape, or may be fully cured. The degree of curing of the composition can be quantitatively measured by known dynamic mechanical analysis (DMA).

[0055] <Varnish-like Composition and Molded Articles Thereof> The composition of the present invention can also be made into a viscous liquid varnish by using a solvent and adjusting the composition and blending ratio. For example, a sufficient amount of solvent and / or an appropriate amount of liquid monomer can be used to make the composition into a varnish. When used as a varnish, it is preferable to add an appropriate solvent to the composition of the present invention. The solvent is used to adjust the viscosity and fluidity of the composition as a varnish. A solvent with a high boiling point at atmospheric pressure, i.e., low volatility, contributes to a uniform thickness of the applied film, so a solvent with a boiling point above a certain level is preferred. A preferred boiling point is approximately 110°C or higher and 300°C or lower at atmospheric pressure. Examples of solvents suitable for such varnishes include toluene, xylene, mesitylene, ethylbenzene, limonene, ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether. The amount of the solvent used is preferably in the range of 10 to 2,000 parts by mass per 100 parts by mass of the composition of the present invention.

[0056] The varnish can be applied to or impregnated into a substrate, and the solvent or the like can be removed by drying or the like to produce an uncured or semi-cured molded article. This molded article generally has the form of a sheet, film, or tape. In this embodiment, the obtained uncured or semi-cured molded article is cured.

[0057] <Curing> The thermoplastic or semi-cured molded article or the composition in the form of a varnish can be cured by a known method, taking into consideration the curing conditions (temperature, time, pressure) of the azo compound contained therein.

[0058] The resin composition of the present invention can be sufficiently cured by curing. The degree of curing can be evaluated by the gel content, which is greater than 50%, preferably greater than 80%, and particularly preferably greater than 90%. A cured product obtained by curing a resin composition comprising a curable resin containing the cyclic olefin monomer units of the present invention and an azo compound exhibits a significantly lower dielectric tangent value than a cured product obtained using, for example, a curable resin containing the same cyclic olefin monomer units and a curing agent other than an azo compound (e.g., peroxide). Furthermore, while a hydrocarbon curing agent (2,3-dimethyl-2,3-diphenylbutane) composed only of carbon and hydrogen atoms requires curing conditions of approximately 250°C to cure the resin composition, azo compounds are generally preferred because they can be cured at relatively low temperatures below 200°C. Therefore, in one embodiment of the present invention, the temperature for curing the resin composition of the present invention is preferably 100°C to 250°C, and more preferably 100°C to 200°C. The curing time can be appropriately selected depending on the actual operating conditions, but is usually within the range of 3 minutes to 180 minutes, typically about 1 to 2 hours.

[0059] Furthermore, in the resin composition of the present invention, when a composition containing an azo compound in an amount of 1% by mass or less, based on the curable resin containing cyclic olefin monomer units, is cured, it is referred to as "single curing." In this case, the resulting cured product can have a dielectric dissipation factor of 0.0010 or less. In particular, using an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer as the curable resin containing cyclic olefin monomer units is preferable, since the resulting cured product can have a dielectric dissipation factor of less than 0.0006. Here, the gel content is a value obtained in accordance with the aforementioned JIS K6796:1998 (or ASTM D2765-84, which corresponds to ISO 10147:1994, which corresponds to JIS), and the dielectric dissipation factor is a value obtained at 23°C and 40 GHz. Furthermore, a cured product obtained from a resin composition containing an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer as a curable resin containing a cyclic olefin monomer unit can have a wide range of physical properties depending on the copolymer composition, and for example, the storage modulus at 25°C can be adjusted in the range of approximately 1 MPa to 3000 MPa. Furthermore, the cured product of the present invention can exhibit a storage modulus at 300°C of 1 MPa or more.

[0060] <General Uses of Composition> The composition of the present invention can be used as a material for base materials / 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) boards, single-layer or multi-layer FCCL (flexible copper clad laminate) boards, and RCC (resin coated copper). It can also be used as various electrical insulating materials for wiring, preferably high-frequency signal wiring, such as coverlays, high-frequency transmission circuits, antennas, solder resists, build-up materials, interlayer insulating materials, bonding sheets, interlayer adhesives, and bump sheets for flip-chip bonders.

[0061] In one embodiment of the present invention, there is also provided a method for producing an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer that can be preferably used in the present invention, including the method for producing the copolymer of the present invention described above, in which the α-olefin, cyclic olefin, aromatic vinyl compound, and aromatic polyene monomers are copolymerized by coordination polymerization.

[0062] Coordination polymerization is a polymerization method using a coordination polymerization catalyst consisting of a transition metal compound and a co-catalyst. As the transition metal compound, transition metal compounds containing zirconium, hafnium, titanium, iron, nickel, cobalt, and palladium are preferred. In particular, for copolymerizing cyclic olefin monomers, transition metal compounds containing zirconium, titanium, nickel, iron, and palladium are preferred. The most preferred coordination polymerization catalyst is a coordination polymerization catalyst consisting of a transition metal compound represented by the following general formula (1) and a co-catalyst. More preferably, the production method may include a step of copolymerizing each of the monomers of an α-olefin, a cyclic olefin, an aromatic vinyl compound (if included), and an aromatic polyene using a polymerization catalyst consisting of a transition metal compound represented by the following general formula (1) and a co-catalyst:

[0063] General formula (1)

[0064] 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, and an unsubstituted or substituted indenyl group.

[0065] Y is a methylene group, silylene group, ethylene group, germylene group, or boron residue having a bond to A and B and having hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as a substituent. The substituents may be different or the same. Y may also have a cyclic structure. Most preferably, Y is a methylene group having a bond to A and B and having hydrogen or a hydrocarbon group having 1 to 15 carbon atoms (which may contain 1 to 3 nitrogen, oxygen, sulfur, phosphorus, or silicon atoms) as a substituent.

[0066] X is hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylaryl group having 8 to 12 carbon atoms, a silyl group having a hydrocarbon substituent having 1 to 4 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or a dialkylamide group having an alkyl substituent having 1 to 6 carbon atoms.

[0067] M is a transition metal, and may preferably be zirconium, hafnium, or titanium.

[0068] In order to obtain a copolymer having a relatively low molecular weight and a low viscosity when made into a varnish, preferably, A and B in the above general formula (1) may each independently be a group selected from an unsubstituted or substituted cyclopentadienyl group or an unsubstituted or substituted indenyl group, and it is particularly preferable to use a transition metal compound having both an unsubstituted or substituted cyclopentadienyl group and an unsubstituted or substituted indenyl group. In order to obtain a copolymer having a high aromatic polyene content, i.e., a copolymer having a high number of vinyl groups and / or vinylene groups derived from aromatic polyene monomer units per number average molecular weight, it is preferable to use a transition metal compound having at least one group selected from an unsubstituted or substituted indenyl group or an unsubstituted or substituted benzoindenyl group. In the case of a copolymer having a high aromatic polyene monomer unit content, it is possible to increase the crosslink density of the cured product obtained by curing, and a cured product having a storage modulus of 5 MPa or more measured at 280°C can be obtained, for example.

[0069] The cocatalyst in the polymerization catalyst of the present invention can be a known cocatalyst used in combination with a transition metal compound. Preferred examples of such cocatalysts include aluminum compounds and boron compounds. Alumoxanes such as methylaluminoxane (also referred to as methylalumoxane or MAO) are preferably used as the aluminum compound. Alternatively, alkylaluminums such as triisobutylaluminum and triethylaluminum may be used. Examples of such cocatalysts include the cocatalysts and alkylaluminum compounds described in EP 0872492A2, JP 11-130808 A, JP 9-309925 A, WO 00 / 20426 A, EP 0985689A, and JP 6-184179 A.

[0070] Examples of the boron compound (boron-containing promoter) include trispentafluorophenylborane, triphenylcarbenium tetrakis(pentafluorophenyl)borate {trityltetrakis(pentafluorophenyl)borate}, lithium tetrakis(pentafluorophenyl)borate, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, tri(n-butyl)ammonium tetra(p-tolyl)phenylborate, tri(n-butyl)ammonium tetra(p-ethylphenyl)borate, tri(n-butyl)ammonium tetra(pentafluorophenyl)borate, trimethylammonium tetra(p-tolyl)borate, trimethylammonium tetrakis-3,5-dimethylphenylborate, triethylammonium tetra tetrakis-3,5-dimethylphenylborate, tributylammonium tetrakis-3,5-dimethylphenylborate, tributylammonium tetrakis-2,4-dimethylphenylborate, anilinium tetrakispentafluorophenylborate, N,N'-dimethylanilinium tetraphenylborate, N,N'-dimethylanilinium tetrakis(p-tolyl)borate, N,N'-dimethylanilinium tetrakis(m-tolyl)borate, N,N'-dimethylanilinium tetrakis(2,4-dimethylphenyl)borate, N,N'-dimethylanilinium tetrakis(3,5-dimethylphenyl)borate, N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N'-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N'-2,4,5-pentamethylanilinium tetraphenylborate, N,N'-2,4,Examples of suitable tetraphenylborate include 5-pentaethylanilinium tetraphenylborate, di-(isopropyl)ammonium tetrakispentafluorophenylborate, di-cyclohexylammonium tetraphenylborate, triphenylphosphonium tetraphenylborate, tri(methylphenyl)phosphonium tetraphenylborate, tri(dimethylphenyl)phosphonium tetraphenylborate, triphenylcarbenium tetrakis(p-tolyl)borate, triphenylcarbenium tetrakis(m-tolyl)borate, triphenylcarbenium tetrakis(2,4-dimethylphenyl)borate, triphenylcarbenium tetrakis(3,5-dimethylphenyl)borate, tropylium tetrakispentafluorophenylborate, tropylium tetrakis(p-tolyl)borate, tropylium tetrakis(m-tolyl)borate, tropylium tetrakis(2,4-dimethylphenyl)borate, and tropylium tetrakis(3,5-dimethylphenyl)borate, but are not particularly limited to these. Although boron-containing cocatalysts in which the fluorine-substituted aromatic group is a phenyl group have been exemplified herein, boron-containing cocatalysts having a fused aromatic group such as a fluorine-substituted naphthyl group can also be preferably used. Among these, preferred boron-containing cocatalysts are those having boron and a fluorine-substituted aromatic group bonded thereto. Examples of such cocatalysts include, but are not limited to, trispentafluorophenylborane, triphenylcarbenium tetrakis(pentafluorophenyl)borate {trityl tetrakis(pentafluorophenyl)borate}, lithium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetra(pentafluorophenyl)borate, tropylium tetrakispentafluorophenylborate, and N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate. Particularly preferred are triphenylcarbenium tetrakis(pentafluorophenyl)borate {trityl tetrakis(pentafluorophenyl)borate} and N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate is used. These most preferred boron-containing cocatalysts are also referred to as TRI-FABA or TRI-FAB, DAN-FABA or DAN-FAB, respectively, and can be purchased from Tosoh Finechem Co., Ltd. or Kanto Chemical Co., Ltd.

[0071] The co-catalyst is used in an aluminum atom / transition metal atomic ratio relative to the metal of the transition metal compound of 0.1 to 100,000, preferably 10 to 10,000. A ratio of 0.1 or more can effectively activate the transition metal compound, while a ratio of 100,000 or less is economically advantageous. The transition metal compound and co-catalyst may be mixed and prepared outside of a polymerization facility, or may be mixed inside the facility during polymerization.

[0072] In particular, the aluminum atom / transition metal atomic ratio of a promoter such as alumoxane relative to the metal of the transition metal compound is preferably 0.1 to 100,000, and more preferably 10 to 10,000. A ratio of 0.1 or more can effectively activate the transition metal compound, and a ratio of 100,000 or less is economically advantageous. When a boron compound is used as the promoter, the boron atom / transition metal atomic ratio is preferably 0.1 to 100, more preferably 0.1 to 10, and most preferably in the range of 0.8 to 1.2. A ratio of 0.1 or more can effectively activate the transition metal compound, and a ratio of 100 or less is economically advantageous.

[0073] In a preferred embodiment, a boron compound is essential, and an aluminum compound may be used as a co-catalyst if necessary. By using a boron compound as a co-catalyst, the amount of metal components such as aluminum derived from the aluminum compound contained in the final copolymer can be reduced, and the dielectric constant and dielectric loss tangent values ​​of the final uncured copolymer, or the dielectric constant and dielectric loss tangent values ​​of the single cured product or composition, can be reduced to particularly preferred ranges. For example, the dielectric constant of the uncured copolymer can be less than 2.5 and the dielectric loss tangent can be less than 0.0006. Furthermore, when a boron compound is used as a co-catalyst, the dielectric constant of the final cured product of the copolymer can be less than 2.5 and the dielectric loss tangent can be less than 0.0006.

[0074] In one embodiment, an uncured α-olefin-cycloolefin-aromatic polyene copolymer or α-olefin-cycloolefin-aromatic vinyl compound-aromatic polyene copolymer can be provided, having a total metal content derived from the catalyst and co-catalyst of 1500 ppm or less, preferably 1000 ppm or less, and most preferably 500 ppm or less. Here, the metal content derived from the catalyst and co-catalyst is defined as the sum of the respective contents of the transition metal elements (as described above) used in the catalyst and the boron and / or aluminum derived from the boron compound and / or aluminum compound used in the co-catalyst, and can be defined as the sum of the respective elemental contents of zirconium, hafnium, titanium, iron, nickel, palladium, cobalt, boron, and aluminum. Particularly preferably, the metal derived from the catalyst may be zirconium, and the metal derived from the co-catalyst may be aluminum and boron, and the metal content derived from the catalyst and co-catalyst may be the sum of the respective contents of zirconium, aluminum, and boron. Note that, in this specification, boron is included in the category of metal. The cured product of the present invention obtained using an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer having a total metal content of 1500 ppm or less, preferably 1000 ppm or less, and most preferably 500 ppm or less can exhibit a dielectric constant of less than 2.5 and a dielectric dissipation factor of less than 0.0006 at a measurement frequency of 23°C and 40 GHz.

[0075] The present invention will be described below with reference to examples, but the present invention should not be construed as being limited to the following examples.

[0076] The copolymers obtained in the synthesis examples were analyzed by the following means. The contents of vinyl group units derived from ethylene, norbornene, styrene, ethylvinylbenzene, and divinylbenzene in the copolymers were determined by the following methods: 1 H-NMR measurement and quantitative mode 13 C-NMR measurement was performed, and the determination was performed using a known method based on the area intensity of the obtained peak. The sample was dissolved in deuterated 1,1,2,2-tetrachloroethane, and the measurement was performed at 80 to 130°C.

[0077] <Molecular Weight> The molecular weight was determined as the number average molecular weight (Mn) converted to standard polystyrene using GPC (gel permeation chromatography). The measurement was carried out under the following conditions. Column: Two TSK-GEL Multipore HXL-M φ7.8 × 300 mm (manufactured by Tosoh Corporation) connected in series were used. Column temperature: 40°C Solvent: THF Flow rate: 1.0 ml / min Detector: RI detector

[0078] <Gel content> The gel content was determined as boiling toluene insoluble matter according to ASTM D2765-84.

[0079] <Dielectric Constant and Dielectric Loss (Dielectric Loss Tangent)> The dielectric loss tangent was measured using a cavity resonator perturbation method (Agilent Technologies 8722ES Network Analyzer, Keysight Technologies 40 GHz Split Cylinder Resonator) at 23°C and 40 GHz using a 0.1 mm × 25 mm × 30 mm sample cut out from the sheet.

[0080] <Measurement of storage modulus> Using a dynamic viscoelasticity measuring device (TA Instruments, formerly Rheometrics RSA-G2), measurements were taken at a frequency of 1 Hz while increasing the temperature from room temperature (23°C), and the storage modulus at 25°C and 280°C was measured. A measurement sample (3 mm x 40 mm) was cut out from a film with a thickness of approximately 0.1 mm and measured to measure the storage modulus. The main measurement parameters involved in the measurement were as follows: Measurement frequency: 1 Hz Heating rate: 3°C / min Sample measurement length: 10 mm Strain: 0.1%

[0081] <Quantification of Metal Content in Copolymer> The metal content (in the example below, the respective contents of transition metal elements used in the metal catalyst, and boron and aluminum used in the co-catalyst) was measured as follows. Furthermore, the contents of hafnium, titanium, iron, nickel, cobalt, and palladium were also quantified. Measurement was performed by ICP atomic emission spectrometry under the following conditions in accordance with JIS K0116:2014. 0.5 g of the composition to be measured was weighed into a platinum crucible and incinerated on a hot plate, an electric stove, and an electric furnace (gradually heated to 600°C). 0.5 ml of HCl (1+1) (i.e., a 1:1 volumetric mixture of hydrochloric acid and water) and ultrapure water were added to the residue, which was dissolved by heating and then adjusted to a constant volume of 5 ml to form a test solution. Quantitative analysis was performed by ICP atomic emission spectrometry (using an Agilent 5110VDV).

[0082] Comparative Synthesis Example 1: Copolymer Production CP-1 The raw material divinylbenzene (DVB) was "DVB-810" (liquid at room temperature, a mixture of meta and para isomers containing 81% by mass of divinylbenzene, with the remainder being ethylvinylbenzene), manufactured by Nippon Steel Chemical & Material Co., Ltd. A 10 L polymerization vessel equipped with a heating and cooling jacket and a stirrer was used. First, the atmosphere inside the thoroughly dried polymerization vessel was purged with nitrogen, and 30 kg of toluene, 2.3 kg of styrene, and 305 g of pure divinylbenzene were charged, and approximately 300 L of dry nitrogen was bubbled in at an internal temperature of 50°C. Thereafter, the atmosphere inside the polymerization vessel was purged with ethylene gas, and 20 mmol of TIBA (manufactured by Kanto Chemical Co., Inc.) was added in an amount equivalent to the number of moles of aluminum, followed by stirring. The internal temperature was stabilized at 60°C, and the internal pressure of the polymerization vessel was increased to 0.1 MPaG (gauge) by ethylene supply and stabilized. Then, from a catalyst tank installed above the polymerization vessel, a catalyst solution was added, prepared by stirring and dissolving 260 micromoles of tritylium tetrakis(pentafluorophenyl)borate in 310 g of a toluene solution containing 210 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 2.5 millimoles of triisobutylaluminum, to initiate polymerization. Ethylene consumed in the polymerization was gradually replenished, and polymerization was continued while maintaining the internal temperature at 60°C and the internal pressure at 0.1 MPaG. After approximately 1 hour of polymerization, when the ethylene consumption reached 600 g, the ethylene gas in the polymerization vessel was vented and returned to normal pressure, and 60 g of isopropanol, a polymerization terminator, was added to the polymerization vessel to terminate the polymerization. The resulting polymerization solution was concentrated under reduced pressure to obtain ethylene-styrene-divinylbenzene copolymer CP-1. The composition and molecular weight of this copolymer are shown in Table 1.

[0083] Formula (2)

[0084] Synthesis Example 1: Copolymer Production P-1 The same procedure as in the synthesis of CP-1 was repeated, except that the amounts of toluene used were changed to 2.5 kg, styrene to 2 kg, divinylbenzene to 490 g (net), and norbornene to 230 g (net). The catalyst solution was changed to 170 g of a toluene solution containing 120 micromoles of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride and 1.4 mmoles of triisobutylaluminum, to which 140 micromoles of tritylium tetrakis(pentafluorophenyl)borate was dissolved with stirring. Polymerization was terminated when the ethylene consumption reached 250 g, yielding an ethylene-norbornene-styrene-divinylbenzene copolymer P-1. The composition and molecular weight of this copolymer are shown in Table 1.

[0085] Comparative Example 1: Preparation of Cured Sheet CP-1 obtained in Comparative Synthesis Example was diluted with toluene and poured in small amounts into a sufficiently large amount of methanol and stirred. The precipitated polymer was filtered and dried at room temperature under vacuum for 24 hours to obtain a purified polymer. The composition and molecular weight of the obtained CP-1 are shown in Table 1. The purified polymer was redissolved in toluene, and 500 ppm each of 4-tert-butylcatechol (TBC) and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyltoluene (TEMPOL) based on the pure polymer content were added to obtain a 50% by mass toluene solution (varnish). Furthermore, 0.75 parts by mass of a curing agent (Perbutyl P) was added and dissolved relative to the parts by mass of the copolymer, followed by stirring and mixing to obtain a varnish-like composition. A mold made from a silicone rubber sheet (frame length 7 cm, width 7 cm, thickness 1 mm) was placed on a smooth Teflon sheet, and the varnish was poured into it and dried in a vacuum dryer at 80°C for at least 10 hours. The silicone rubber mold was then removed, and a stainless steel mold (frame length 11 cm, width 11 cm, thickness 0.2 mm) was placed in place. The mold was then pressed in a press at 200°C for 2 hours under a load of 5 MPa. The Teflon sheet and stainless steel mold were then removed to obtain a cured sheet. The sheet was then cut into small pieces and the gel content was measured. The gel content measurement results confirmed that the sheet was in a cured state. The sheet was then subjected to viscoelasticity spectroscopy (DMA) to measure the storage modulus at 25°C and 300°C. The dielectric properties of the sheet were measured at 23°C and 40 GHz. The results are shown in Table 2.

[0086] Comparative Example 2: Preparation of cured sheet A cured sheet was prepared using P-1 in the same manner as in Comparative Example 1. The physical properties were measured in the same manner as in Comparative Example 1. The results are shown in Table 2.

[0087] Example 1: Preparation of cured sheet A cured sheet was prepared using P-1 in the same manner as in Comparative Example 1. However, instead of Perbutyl P, an azo compound VR-110 was used as the curing agent in an amount of 0.75 parts by mass relative to the parts by mass of the copolymer. Physical properties were measured in the same manner as in Comparative Example 1. The results are shown in Table 2.

[0088] When ethylene-styrene-divinylbenzene copolymer (CP-1) was cured with an azo compound (Comparative Example 1), a cured product with a low dielectric loss tangent satisfying the requirements of the present invention was not obtained. Furthermore, when ethylene-norbornene-styrene-divinylbenzene copolymer (P-1) containing a cyclic olefin monomer unit as a constituent was cured with the peroxide Perbutyl P (Comparative Example 2), a cured product with a low dielectric loss tangent satisfying the requirements of the present invention was not obtained. When ethylene-norbornene-styrene-divinylbenzene copolymer (P-1) was cured with an azo compound (VR-110), a cured product with a low dielectric loss tangent satisfying the requirements of the present invention was obtained.

[0089]

[0090]

Claims

1. A resin composition comprising a curable resin containing a cyclic olefin monomer unit and an azo compound.

2. The composition of claim 1, wherein said curable resin further comprises aromatic polyene monomer units and aromatic vinyl units.

3. The composition according to claim 2, wherein said curable resin has an aromatic vinyl group as a functional group.

4. The composition of claim 1, wherein the curable resin is an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer.

5. The composition according to claim 4, comprising an α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer satisfying all of the following requirements (1) to (6): (1) the number average molecular weight is 500 or more and 30,000 or less; (2) the α-olefin units are α-olefins having 2 to 20 carbon atoms; (3) the aromatic vinyl compound units are aromatic vinyl compounds having 8 to 20 carbon atoms; (4) the cyclic olefin units are cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 10% by mass or more and less than 99% by mass; (5) the aromatic polyene units are one or more polyenes having 5 to 20 carbon atoms and having multiple vinyl groups and / or vinylene groups in the molecule, the content of vinyl groups and / or vinylene groups derived from aromatic polyene units contained in the copolymer is 2 or more per number average molecular weight, and the number average molecular weight per vinyl group and / or vinylene group derived from the aromatic polyene monomer units is 250 or more and 10,000 or less. (6) The total content (mass %) of each monomer unit of an α-olefin, a cyclic olefin, an aromatic vinyl compound, and an aromatic polyene is 100 mass %.

6. A method for producing a cured product using the resin composition according to any one of claims 1 to 5.

7. The manufacturing method according to claim 6, which comprises using 0.01 to 5 parts by weight of an azo-based curing agent per 100 parts by weight of the curable resin.

8. The method of claim 6, wherein the curing is carried out at a temperature of 100°C to 250°C for 3 minutes to 180 minutes.

9. A cured product of the resin composition according to any one of claims 1 to 5.

10. The cured product according to claim 9, which has a dielectric constant of less than 2.5 and a dielectric loss tangent of 0.0005 or less, measured at 23°C and 40 GHz.

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