Organic crosslinked particles

Abstract

Provided are organic crosslinked particles having excellent low dielectric properties. The organic crosslinked particles comprise an olefin-aromatic vinyl compound-aromatic polyene copolymer.

Description

organic crosslinked particles

[0001] The present invention relates to organic crosslinked particles containing an olefin-aromatic vinyl compound-aromatic polyene copolymer and compositions containing the same.

[0002] As communication frequencies shift to the gigahertz range and, especially, the millimeter-wave band (30 GHz and above), the demands for low dielectric properties in insulators used in multilayer substrates (PCBs) made of copper clad laminate (CCL), flexible copper clad laminate (FCCL), and resin-coated copper (RCC) are becoming increasingly stringent. As Moore's Law approaches its limits due to increasing wiring density, in addition to the traditional high-density wiring in semiconductor devices, high integration (chiplets) is required through three-dimensional packaging and functional integration between component devices. In this context, as device wiring becomes increasingly multilayered, miniaturized, and denser, substrates and insulating materials are required to prevent high-frequency signal delays and noise generation, particularly those with low dielectric constants and low dielectric loss tangents. While fluororesins such as perfluoroethylene possess excellent low dielectric constants, low dielectric loss, and excellent heat resistance, their application to multilayer substrates is hampered by their difficult moldability and film formability, as well as issues with adhesion to copper foil. On the other hand, substrates and insulating materials made of post-cured resins such as epoxy resins, unsaturated polyester resins, polyimide resins, and phenolic resins have been widely used due to their heat resistance and ease of handling, but their dielectric constants and dielectric losses are relatively high, and improvements are desired as insulating materials for high frequency applications.

[0003] Therefore, hydrocarbon-based resins, which inherently possess low dielectric properties, have attracted attention. To convert hydrocarbon-based resins, which are essentially thermoplastic resins, into curable resins requires the introduction of functional groups. However, functional groups that react to radicals or heat generally have polarity, which compromises their low dielectric properties. Introducing functional groups composed solely of hydrocarbons, such as aromatic vinyl groups, often requires the use of expensive intermolecular reactions between hydrocarbon monomers, which is often uneconomical. Patent Document 1 discloses a cured product containing an ethylene-aromatic vinyl compound-aromatic polyene copolymer obtained from a specific coordination polymerization catalyst and having a specific composition and blend. The technology disclosed therein selectively copolymerizes only one of the two vinyl groups of the aromatic polyene (divinylbenzene), preserving the remaining vinyl group, thereby easily producing a crosslinkable hydrocarbon-based copolymer macromonomer with aromatic vinyl group functional groups. Cured products obtained from similar olefin-aromatic vinyl compound-aromatic polyene copolymers and compositions containing auxiliary materials, etc., are characterized by low dielectric constants and low dielectric dissipation factors (Patent Document 2). A relatively low-viscosity varnish comprising a relatively low molecular weight olefin-aromatic vinyl compound-aromatic polyene copolymer, an additive resin, a monomer, and a solvent is also known (Patent Document 3). A liquid curable resin composition comprising an olefin-aromatic vinyl compound-aromatic polyene copolymer and a non-polar vinyl compound is also known (Patent Document 4).

[0004] JP 2009-161743 A International Publication No. 2021 / 112087 International Publication No. 2022 / 014599 International Publication No. 2024 / 014436

[0005] The olefin-aromatic vinyl compound-aromatic polyene copolymers described in the above-mentioned published patent documents and the cured products obtained from compositions containing the copolymers and hard components having curable functional groups all exhibit good low dielectric properties, such as low dielectric tangent values. However, the hard components having curable functional groups contained in considerable amounts (e.g., polyphenylene ethers, bismaleimides, aromatic polyene resins, etc.) do not have sufficient low dielectric properties, and there is room for improvement in terms of the low dielectric properties of the cured products.

[0006] The present invention was completed in consideration of the above-mentioned problems, and aims to provide, in one embodiment, organic crosslinked particles having excellent low dielectric properties. In another embodiment, the present invention aims to provide a composition containing such organic crosslinked particles and a curable resin, and a cured product of the composition.

[0007] As a result of extensive research by the present inventors into the problems that could not be solved by the above-mentioned conventional techniques, it was discovered that organic crosslinked particles containing an olefin-aromatic vinyl compound-aromatic polyene copolymer and having a specific particle size range can solve the above-mentioned problems. That is, the present invention can provide the following aspects.

[0008] [Aspect 1] Organic crosslinked particles comprising an olefin-aromatic vinyl compound-aromatic polyene copolymer. [Aspect 2] The organic crosslinked particles according to Aspect 1, having a median diameter D50 in the range of 0.1 to 5.0 μm. [Aspect 3] The organic crosslinked particles according to Aspect 1, further comprising a polyfunctional monomer. [Aspect 4] I (3025 cm) measured by IR -1 : aromatic C-H expansion / contraction) / I (2920cm -1Aspect 5: The organic crosslinked particle according to aspect 1, wherein the gel content is 80% by mass or more. Aspect 6: The organic crosslinked particle according to aspect 1, wherein the glass transition temperature (Tg) measured by DSC is 100°C or more and 350°C or less. Aspect 7: The organic crosslinked particle according to aspect 1, wherein the olefin-aromatic vinyl compound-aromatic polyene copolymer satisfies all of the following (1) to (5): (1) the number average molecular weight of the copolymer is 500 or more and 50,000 or less; (2) the aromatic vinyl compound monomer is an aromatic vinyl compound having 8 to 20 carbon atoms, and the content of the aromatic vinyl compound monomer unit is 0.1% by mass or more and 70% by mass or less. (3) The olefin monomer unit is one or more selected from α-olefin monomer units having from 2 to 30 carbon atoms and cyclic olefin monomer units having from 7 to 30 carbon atoms, and the content thereof is from 5% to 95% by mass. (4) The aromatic polyene monomer is one or more selected from polyenes having from 5 to 20 carbon atoms and having multiple vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units is from 2 to 30 per number average molecular weight. (5) The total of the olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass. [Aspect 8] The organic crosslinked particle according to aspect 1, wherein the olefin is an olefin-aromatic vinyl compound-aromatic polyene copolymer containing at least a cyclic olefin component. [Aspect 9] The organic crosslinked particles according to Aspect 1, which are olefin-aromatic vinyl compound-aromatic polyene copolymers having a dielectric constant of 2.5 or less and a dielectric loss tangent of 0.0010 or less, measured at 10 GHz and 23°C. [Aspect 10] A method for producing the organic crosslinked particles according to any one of Aspects 1 to 9, comprising emulsion polymerization using the olefin-aromatic vinyl compound-aromatic polyene copolymer and a polyfunctional monomer. [Aspect 11] A composition comprising the organic crosslinked particles according to any one of Aspects 1 to 9. [Aspect 12] The composition according to Aspect 11, further comprising a curable resin.[Aspect 13] The composition according to aspect 11, wherein the curable resin is one or more selected from the group consisting of an olefin-aromatic vinyl compound-aromatic polyene copolymer, a hydrocarbon-based elastomer, a polyether-based resin having multiple functional groups in one molecule, including polyphenylene ether, and an aromatic polyene-based resin. [Aspect 14] A cured product of the composition according to aspect 11. [Aspect 15] The cured product according to aspect 14, which is in the form of a sheet. [Aspect 16] The cured product according to aspect 14, which has a coefficient of linear expansion (CTE) from 0°C to 200°C of 150 ppm or less. [Aspect 17] A CCL, FCCL, interlayer insulating material, or RCC, comprising the organic crosslinked particles according to any one of aspects 1 to 9. [Aspect 18] A CCL, FCCL, interlayer insulating material, or RCC, comprising the cured product according to aspect 14.

[0009] According to the present invention, it is possible to provide organic crosslinked particles having excellent low dielectric properties. A cured product of a composition containing the crosslinked particles also exhibits excellent low dielectric properties.

[0010] The cured product obtained by the present invention is useful as an insulating component for single-layer or multi-layer CCL, FCCL, RCC, interlayer insulating material, or package, and further as an insulating material for multilayered, miniaturized, and high-density high-frequency transmission wiring such as chiplets, various three-dimensional mounting substrates, rewiring layers, and interposers.

[0011] 1 is a TEM (transmission electron microscope) photograph of organic crosslinked particles 1 obtained in Example 1.

[0012] 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.

[0013] In one embodiment, the present invention relates to organic crosslinked particles comprising an olefin-aromatic vinyl compound-aromatic polyene copolymer and having an average particle size d50 in the range of 0.1 to 5.0 μm. In another embodiment, the present invention relates to organic crosslinked particles comprising at least an olefin-aromatic vinyl compound-aromatic polyene copolymer and a polyfunctional monomer.

[0014] The olefin-aromatic vinyl compound-aromatic polyene copolymer used in the present invention can be obtained by copolymerizing the olefin, aromatic vinyl compound, and aromatic polyene monomers. The copolymerization type may be either statistical or block, with statistical copolymerization being preferred. The presence of an olefin-aromatic vinyl compound-aromatic polyene copolymer in the organic crosslinked particles can be determined by infrared spectroscopy (IR), Raman spectroscopy, pyrolysis gas chromatography, or solid-state NMR. The average particle size of the organic crosslinked particles containing the copolymer is expressed as the particle size at which the cumulative value of the volume-based cumulative particle size distribution reaches 50% (median diameter, d50), and is preferably in the range of 0.1 to 5.0 μm, more preferably 0.3 to 3.5 μm. By maintaining the average particle size of the organic crosslinked particles within the above range, the dielectric properties and expansion coefficient of the final cured product can be improved. The shape of the organic crosslinked particles is arbitrary, but spherical is preferred. In this specification, organic crosslinked particles are considered spherical if their minimum diameter is within -20% of their maximum diameter in three dimensions.

[0015] The following IR measurement is an index showing the proportion of the aromatic polyene component contained in the organic crosslinked particles of the present invention. ap Value = I (3025 cm -1 : aromatic C-H expansion / contraction) / I (2920cm -1 It is preferable that I (3025 cm: aliphatic C-H stretch) is 0.10 or more and 1.20 or less, preferably 0.15 or more and 1.00 or less. -1 : Aromatic C-H stretching) is 2025 cm -1 is the absorption peak intensity related to aromatic C-H stretching vibration that appears around I (2920 cm -1 : Aliphatic C-H stretching) is 2920 cm -1 These peak intensities are determined as the difference in absorbance between the baseline and the peak top, with the tangent line connecting the bottom of the peak on the high wavenumber side and the low wavenumber side nearest to the peak being used as the baseline. ap A higher value indicates a higher proportion of aromatic polyene components contained in the organic crosslinked particles.

[0016] Another index indicating the proportion of aromatic polyene components contained in the organic crosslinked particles of the present invention is the glass transition temperature. The glass transition temperature of the organic crosslinked particles themselves can be determined by DSC (differential scanning calorimetry). Because it is often difficult to form organic crosslinked particles into sheets by themselves, it is preferable to determine the glass transition temperature by DSC rather than DMA (dynamic mechanical analysis). This glass transition temperature is the midpoint glass transition temperature determined in the second run. The glass transition temperature (Tg) of the organic crosslinked particles is preferably 100°C or higher and 350°C or lower. It is noteworthy that even if the olefin-aromatic vinyl compound-aromatic polyene copolymer used does not contain a cyclic olefin component and therefore has a glass transition temperature (here, Tg obtained by DMA) as low as -10°C, the organic crosslinked particles of the present invention can exhibit a glass transition temperature (DSC) of 100°C or higher. The use of a polyfunctional monomer in the production of organic crosslinked particles can impart a higher glass transition temperature than a cured product of an olefin-aromatic vinyl compound-aromatic polyene copolymer alone.

[0017] The gel content of the organic crosslinked particles is preferably 80% by mass or more, more preferably 90% by mass or more, as measured in accordance with JIS K6796:1998 or ASTM D2765-84, which corresponds to ISO10147:1994, which corresponds to JIS.

[0018] The olefin-aromatic vinyl compound-aromatic polyene copolymer used in the present invention may preferably satisfy all of the following (1) to (5): (1) the number-average molecular weight of the copolymer is 500 to 50,000; (2) the aromatic vinyl compound monomer is an aromatic vinyl compound having from 8 to 20 carbon atoms, and the content of the aromatic vinyl compound monomer is from 0.1 to 70 mass%; (3) the olefin monomer unit is one or more selected from an α-olefin monomer unit having from 2 to 30 carbon atoms and a cyclic olefin monomer unit having from 7 to 30 carbon atoms, and the content thereof is from 5 to 95 mass%; (4) the aromatic polyene monomer is one or more selected from polyenes having from 5 to 20 carbon atoms and having multiple vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer unit is from 2 to 30 per number-average molecular weight. (5) The total amount of the olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass.

[0019] In the present invention, an olefin-aromatic vinyl compound-aromatic polyene copolymer containing at least a cyclic olefin monomer unit as an olefin monomer unit is preferred. By including a cyclic olefin in the copolymer, the dielectric constant and dielectric dissipation factor of the crosslinked organic particles themselves and a cured product containing the crosslinked organic particles can be kept below a certain value. Furthermore, by including a cyclic olefin monomer unit in the copolymer, the coefficient of linear expansion (CTE) of the crosslinked organic particles themselves and a cured product containing the crosslinked organic particles can be reduced compared to when the copolymer does not include a cyclic olefin.

[0020] Here, the olefin monomer (which refers to a monomer that is the basis of the olefin monomer units in the copolymer, but in this specification, the terms "monomer" and "monomer unit" (or "unit") may be used interchangeably depending on the context; the same applies to similar terms hereinafter) refers to one or more selected from α-olefin monomers having from 2 to 20 carbon atoms and cyclic olefin monomers having from 7 to 30 carbon atoms. Examples of α-olefin monomers having from 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene. Preferably, the α-olefin monomer is a combination of ethylene and an α-olefin other than ethylene, and most preferably ethylene. In the copolymer, the content of the α-olefin monomer units is arbitrary, but is preferably from 0 to 70% by mass, more preferably from 0 to 60% by mass, and even more preferably from 1 to 60% by mass. The higher the α-olefin monomer unit content (for example, 5% by mass or more), the easier it is to avoid the copolymer and its cured product from becoming brittle, which is preferable.

[0021] 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.

[0022] 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.

[0023] 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. Norbornenes having such aromatic substituents can impart a higher glass transition temperature (Tg) to the copolymer when copolymerized, 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.

[0024] The content of cyclic olefin monomer units contained in the copolymer is arbitrary. However, when the objective is to achieve a high glass transition temperature (Tg) of the copolymer, the optimal content of cyclic olefin monomer units contained in the copolymer varies depending on the type of cyclic olefin. For example, it is 50% by mass to 95% by mass, preferably 60% by mass to 95% by mass, more preferably 70% by mass to 95% by mass, and most preferably 80% by mass to 95% by mass. The higher the content of cyclic olefin monomer units, the higher the Tg of the copolymer. The optimal content of cyclic olefin units contained in the copolymer may be less than 90% by mass from the viewpoint of imparting a certain degree of toughness to the copolymer. 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 to 350°C, more preferably 130°C to 300°C, and most preferably 180°C to 300°C. On the other hand, when the content of cyclic olefin monomer units is in the range of 10% by mass to less than 50% by mass, a copolymer with a relatively low Tg is obtained. In particular, in the case of a copolymer that is soft at room temperature, the content of the cyclic olefin monomer unit is in the range of 10% by mass or more and less than 40% by mass. By copolymerizing the cyclic olefin monomer unit, a lower dielectric constant, particularly a lower dielectric loss tangent, can be obtained for the copolymer itself and its cured product, compared to a copolymer that does not contain the cyclic olefin monomer unit, which is preferable.

[0025] 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.

[0026] The aromatic vinyl compound monomer is an aromatic vinyl compound having from 8 to 20 carbon atoms, such as styrene, paramethylstyrene, ethylvinylbenzene, paraisobutylstyrene, various vinylnaphthalenes, and various vinylanthracenes. The aromatic vinyl compound monomer of this embodiment has at least one vinyl group or vinylene group within the monomer. The aromatic vinyl compound-derived monomer unit may be contained in the copolymer as a result of copolymerization of an aromatic vinyl compound component contained as an impurity in the aromatic polyene used in polymerization. The content of the aromatic vinyl compound monomer unit 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.

[0027] When the content of aromatic vinyl compound monomer units is 10% by mass or more, the aromaticity of the copolymer can be improved, the compatibility with other resin materials, flame retardants, and fillers is improved, the bleed-out of flame retardants is suppressed, and high filler loading is facilitated, which is preferable. As described above, the glass transition temperature and aromaticity of the copolymer can be adjusted by the content of cyclic olefin monomer units and the content of aromatic vinyl compound monomer units of the copolymer.

[0028] 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.

[0029] The number-average molecular weight of the copolymer of the present invention is preferably 500 to 50,000, more preferably 500 to 30,000 or less than 30,000, even more preferably 500 to 15,000 or less than 15,000, and even more preferably 500 to 12,000 or less than 12,000. A number-average molecular weight of 500 or more improves the mechanical properties of the composition in the uncured state and provides appropriate adhesion, thereby facilitating molding and processing as a thermoplastic resin. A number-average molecular weight of 30,000 or less improves molding processability. In particular, a number-average molecular weight of 30,000 or less, or 12,000 or less, is 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.

[0030] 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 The composition can be determined by comparing the composition obtained by C-NMR measurement with the vinyl group content derived from aromatic polyene monomer units. Such a method is obvious and well known to those skilled in the art. For example, the composition of an ethylene-norbornene-styrene-ethylvinylbenzene-divinylbenzene copolymer, which is a representative example of the copolymer of the present invention, can also be determined by the following method. 1 H-NMR measurement and quantitative mode 13 C-NMR measurement was performed, and the NMR peak area intensity of the aromatic vinyl / vinylene group ( 1 H. 13 C) to determine the proportion (a) of divinylbenzene units contained, and the strength of the ethyl groups connected to the benzene ring ( 1 H. 13C) to determine the proportion (b) of ethylvinylbenzene units contained in small amounts as impurities in divinylbenzene, and calculate the area intensity ( 1 H. 13 The proportion (c) of styrene units is calculated by subtracting the contributions of (a) and (b) from (C), and finally the area intensity of the aliphatic hydrocarbon region ( 1 H. 13 The ratio (d) of olefin units (total of ethylene and norbornene units) is calculated by subtracting the contributions of the contents of (a), (b), and (c) from the ratio (c) of olefin units (total of ethylene and norbornene units). 13 From C), the abundance ratio (e) of ethylene and norbornene units can be determined, and the contents of ethylene, norbornene, styrene, divinylbenzene, and ethylvinylbenzene can be calculated by combining (a), (b), (c), (d), and (e).

[0031] The content of aromatic polyene monomer units in the copolymer of the present invention is arbitrary, but is preferably less than 30% by mass, more preferably less than 18% by mass, and most preferably less than 15% by mass. At such a content, the number of crosslinking groups is appropriately suppressed, and the effect of improving the stability during the production of the copolymer and the stability during curing is obtained.

[0032] Specific examples of the α-olefin-aromatic vinyl compound-aromatic polyene copolymer as one embodiment of the copolymer of the present invention include an ethylene-styrene-divinylbenzene copolymer, an ethylene-ethylvinylbenzene-divinylbenzene copolymer, an ethylene-propylene-styrene-divinylbenzene copolymer, an ethylene-1-octene-styrene-divinylbenzene copolymer, and a propylene-styrene-divinylbenzene copolymer. Specific examples of suitable α-olefin-cyclic olefin-aromatic vinyl compound-aromatic polyene copolymers include one or more members 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-hexene-styrene-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.

[0033] The olefin-aromatic vinyl compound-aromatic polyene copolymer preferably used in the composition of the present invention is a copolymer in which the olefin monomer units contain at least a cyclic olefin monomer unit. By including a cyclic olefin monomer unit as a portion of the olefin monomer units, the dielectric dissipation factor of the copolymer itself can be lowered compared to copolymers containing no cyclic olefin. For example, when a copolymer is cured using a minimum amount of curing agent, the dielectric dissipation factor measured at 10 GHz is lower compared to copolymers containing no cyclic olefin monomer units. Therefore, a copolymer containing cyclic olefin monomer units is preferred for lowering the dielectric dissipation factor, particularly for compositions and cured products thereof. Furthermore, increasing the content of cyclic olefin monomer units as described above increases the glass transition temperature of the copolymer, thereby hardening the copolymer and its cured product. Considering that insulating materials for CCLs, three-dimensional integrated circuit packaging, or chiplets, which are preferred applications of the present invention, are hard and require a lower linear expansion coefficient similar to that of wiring metals such as silicon and copper, a higher content of cyclic olefin monomer units as described above is preferred. Furthermore, a portion of the olefin monomer units in the olefin-aromatic vinyl compound-aromatic polyene copolymer contains cyclic olefin monomer units, and the higher the content of these cyclic olefin monomer units, i.e., the higher the glass transition temperature of the copolymer, the higher the thermal conductivity of the cured product of the composition tends to be.

[0034] In an embodiment of the olefin-aromatic vinyl compound-aromatic polyene copolymer, the content of α-olefin monomer units may be 0% by mass (i.e., no α-olefin monomer units are included). Such a copolymer is also referred to herein as a "cyclic olefin-aromatic vinyl compound-aromatic polyene copolymer."

[0035] In the composition of the present invention, a plurality of the above-mentioned olefin-aromatic vinyl compound-aromatic polyene copolymers having different compositions and molecular weights may be used.

[0036] <Crosslinked Organic Particles Comprising an Olefin-Aromatic Vinyl Compound-Aromatic Polyene Copolymer> The crosslinked organic particles comprising the olefin-aromatic vinyl compound-aromatic polyene copolymer of the present invention can be cured by themselves, or the copolymer of the present invention can be combined with other materials to form a composition, which can then be used as the crosslinked organic particles. These other materials include the following "polyfunctional monomer component," "monofunctional monomer component," "resin component," "solvent," "filler," "other additives," and the like.

[0037] <Polyfunctional Monomer Component> The amount of polyfunctional monomer component that may be contained in the organic crosslinked particles of the present invention is arbitrary, but is preferably 200 parts by mass or less, more preferably 100 parts by mass or less, per 100 parts by mass of the copolymer. Examples of such polyfunctional monomer components include the aromatic polyenes, polyfunctional maleimides, polyfunctional cyanates, polyfunctional (meth)acrylates such as glycidyl (meth)acrylate and trimethylolpropane tri(meth)acrylate, and polyfunctional isocyanurates such as triallyl isocyanurate and tri(meth)acrylic isocyanurate. Among these, aromatic polyenes are preferred from the viewpoint of their excellent low dielectric properties. Among these, ortho-, meta-, and para-divinylbenzenes, or mixtures thereof, are more preferred, and a mixture of meta- and para-divinylbenzene is most preferred.

[0038] <Monofunctional Monomer Component> The amount of monofunctional monomer component that may be contained in the organic crosslinked particles of the present invention is arbitrary, but is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, per 100 parts by mass of the copolymer. 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 are the aromatic vinyl compound monomers described above and / or the aromatic vinylene monomers described below. Such monomers are preferably monomers that can be polymerized with a radical polymerization initiator. The monofunctional monomer component may be a monomer component that constitutes a part of the copolymer of the present invention.

[0039] <Aromatic Vinylene Monomer> The aromatic vinylene monomer that may be contained in the organic crosslinked particles of 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] <Resin Component> The organic crosslinked particles of the present invention may contain any resin component as long as it does not impair the effects of the present invention. Preferably, one or more resins selected from hydrocarbon elastomers, polyether resins, aromatic polyene resins, and olefin-aromatic vinyl compound-aromatic polyene copolymers containing no cyclic olefins are used. Of these, hydrocarbon elastomers and olefin-aromatic vinyl compound-aromatic polyene copolymers containing no cyclic olefins are more preferred. Among hydrocarbon elastomers, conjugated diene polymers are preferred. Among conjugated diene polymers, 1,2-polybutadiene is preferred. The amount of resin components is preferably 100 parts by mass or less, and more preferably 50 parts by mass or less, per 100 parts by mass of the olefin-aromatic vinyl compound-aromatic polyene copolymer. 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. Furthermore, when a resin component is added to the olefin-aromatic vinyl compound-aromatic polyene copolymer, the ratio of the total mass of the olefin-aromatic vinyl compound-aromatic polyene copolymer and the resin component to the mass of the specific boron nitride powder is in the range of 15:85 to 70:30, and preferably in the range of 20:80 to 50:50.

[0041] <Hydrocarbon Elastomer> The hydrocarbon elastomer that can be suitably used 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 EPDM, conjugated diene polymers, block copolymers or random copolymers of aromatic vinyl compounds and conjugated dienes, and hydrogenated products thereof. These hydrocarbon elastomers may be modified, for example, by introducing functional groups with maleic anhydride or other compounds.

[0042] <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.

[0043] <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.

[0044] <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 New 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 a resin (copolymer) substantially composed of aromatic polyene monomer units and aromatic monovinyl compound monomer units, and more preferably, this 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.

[0045] <Solvent> In producing the organic crosslinked particles of the present invention, an appropriate solvent may be added to the composition containing the copolymer, if necessary. The solvent is used to adjust the viscosity, fluidity, and dispersibility of the composition. Volatile solvents are preferred, such as cyclohexane, toluene, ethylbenzene, and mixed alkanes. The amount of solvent used is preferably 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. Generally, the solvent is preferably substantially removed by drying or the like from the organic crosslinked particles obtained by a drying treatment or the like after the composition is subjected to emulsion polymerization as described below.

[0046] <Filler> Inorganic or organic fillers may be added as needed. Known inorganic fillers can be used as the inorganic filler, and are added for purposes such as controlling the coefficient of thermal expansion, controlling thermal conductivity, and reducing cost. From the perspective of reducing the coefficient of thermal expansion, silica, particularly fused silica or fused silica that has been subjected to low-dielectric treatment, is preferably used. From the perspective of imparting thermal conductivity, boron nitride (BN), particularly agglomerated boron nitride with reduced anisotropy, is preferably used. The amount of filler is 100 parts by mass or less, preferably 50 parts by mass or less, per 100 parts by mass of the organic crosslinked particles. From the perspective of low dielectric properties, the addition of a filler increases the dielectric constant, so the amount of inorganic filler used should be kept low, and preferably no filler is added at all.

[0047] Alternatively, 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 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 dissipation factor. The amount of organic filler added is 100 parts by mass or less, preferably 50 parts by mass or less, per 100 parts by mass of the organic crosslinked particles.

[0048] <Other Additives> The composition of the present invention may further contain one or more additives selected from the group consisting of a flame retardant and a surface modifier. The composition of the present invention can be a matrix for organic crosslinked particles.

[0049] <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.

[0050] In addition to the flame retardant, antimony compounds such as antimony trioxide, antimony tetraoxide, antimony pentoxide, and sodium antimonate, or nitrogen-containing compounds such as melamine, triallyl-1,3,5-triazine-2,3,4-(1H,3H,5H)-trione, and 2,4,6-trialyloxy-1,3,5-triazine may be added as a flame retardant aid. The total amount of these flame retardants and flame retardant aids is usually preferably 1 to 100 parts by mass per 100 parts by mass of the composition. Furthermore, a polyphenylene ether (PPE) resin with a low dielectric constant and excellent flame retardancy may be used in an amount of 30 to 200 parts by mass per 100 parts by mass of the flame retardant.

[0051] <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.

[0052] The composition serving as a raw material for producing the organic crosslinked particles of the present invention can be obtained by mixing, dissolving, or melting one or more components selected from the group consisting of "polyfunctional monomer components," "monofunctional monomer components," "resin components," "solvents," "fillers," "other additives," etc., and may further include common additives 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 components.

[0053] <Method for Producing Crosslinked Organic Particles> The crosslinked organic particles of the present invention can be produced by subjecting a composition containing an olefin-aromatic vinyl compound-aromatic polyene copolymer to known emulsion polymerization in the presence of a curing agent, an emulsifier, or a dispersant. In this specification, emulsion polymerization is a concept that also encompasses suspension polymerization in which polymerization is carried out using an emulsifier or a dispersant.

[0054] <Curing Agent> The curing agent that may be included in the present composition may be any known curing agent that can be used for the polymerization or curing of aromatic polyenes or aromatic vinyl compounds. Conventional curing agents, polymerization initiators, and radical generators used in emulsion polymerization may also be used. Examples of such materials include radical polymerization initiators. Preferred curing agents include organic peroxides (peroxides), azo-based (e.g., AIBN), and inorganic peroxides (peroxides such as potassium persulfate or hydrogen peroxide), and can be freely selected depending on the application and conditions. While there are no particular limitations on the amount of curing agent used, a general ratio of 0.01 to 10 parts by mass per 100 parts by mass of the composition (preferably excluding the curing agent and solvent) is generally preferred. When using these curing agents, the curing process should be performed at an appropriate temperature and time, taking their half-life into consideration. The curing conditions can be determined based on the curing agent, but a temperature range of approximately 50°C to 100°C is generally appropriate.

[0055] <Emulsifier> As the emulsifier used in emulsion polymerization, known emulsifiers such as nonionic and anionic emulsifiers can be used. However, in order to avoid the incorporation of metal ions or anions into the finally obtained organic crosslinked particles, nonionic emulsifiers or anionic emulsifiers containing ammonium ions that do not contain metal ions are preferably used. If the emulsifier remains in the obtained organic crosslinked particles, the low dielectric properties of the organic crosslinked particles may deteriorate, and the obtained organic crosslinked particles must be washed. In particular, when an anionic emulsifier is used, the obtained organic crosslinked particles must be thoroughly washed to remove ionic components.

[0056] After the emulsion polymerization is complete, the emulsion is broken (emulsification destruction) by a known method to obtain crosslinked organic particles. To avoid the incorporation of metal ions or anions into the final crosslinked organic particles, the emulsion is preferably broken by adding alcohol, centrifugation, heating / cooling, or other methods. After the emulsion is broken, the water bath is removed, and an organic solvent is added to the organic layer containing the crosslinked organic particles, if necessary, followed by repeated washing with water or other methods to remove any remaining emulsifiers or curing agents. After the water bath is removed, further organic solvent may be added to disperse the crosslinked organic particles in the organic layer and recover them. After the water bath is removed, the organic solvent may be removed by an appropriate method, followed by drying, and the crosslinked organic particles may be recovered as a solid powder.

[0057] <Organic Crosslinked Particles> As described above, the average particle size (median diameter D50) of the organic crosslinked particles obtained from the composition of the present invention is in the range of 0.1 to 5.0 μm, preferably 0.3 to 3.0 μm. Among the organic crosslinked particles of the present invention, organic crosslinked particles containing a relatively soft olefin-aromatic vinyl compound-aromatic polyene copolymer can be formed into a smooth sheet by adding a relatively small amount of aromatic polyene monomer or aromatic vinyl compound and heating and pressing under appropriate conditions. This sheet can then be used to directly measure the dielectric properties of the organic crosslinked particles. Furthermore, among the organic crosslinked particles of the present invention, organic crosslinked particles containing a particularly hard olefin-aromatic vinyl compound-aromatic polyene copolymer cannot be formed into a sheet by heating and pressing. Therefore, a crosslinked sheet can be produced by mixing with another curable resin with known dielectric properties and crosslinking under appropriate conditions. Here, the dielectric properties of the organic crosslinked particles alone can be determined by extrapolation from the dielectric properties of a cured sheet prepared by varying the ratio of organic crosslinked particles to curable resin. The dielectric constant and dielectric loss tangent are measured using a known resonator method. In this specification, the resonator method is performed at 23° C. and a measurement frequency of 10 GHz.

[0058] The dielectric constant of the organic crosslinked particles determined as described above is preferably 2.0 or more and 3.5 or less, more preferably 2.1 or more and 3.0 or less. The dielectric dissipation factor is preferably 0.0002 or more and 0.002 or less, more preferably 0.0002 or more and 0.0010 or less. These values ​​are preferred for an insulating material for high-frequency signals of, for example, 3 GHz or more.

[0059] <Composition Containing Crosslinked Organic Particles> In one embodiment, the present invention relates to a composition containing the crosslinked organic particles. By curing the composition of the present invention, a low-dielectric cured product can be obtained. The crosslinked organic particles can be cured alone in the presence of a curing agent, even without other polymer components. The composition may also contain a solvent for dispersing the crosslinked organic particles. The composition of the present invention may further contain a curable resin. While known curable resins can be used as the curable resin, curable resins that can be cured by radicals are preferred. Preferred curable resins include one or more selected from the "olefin-aromatic vinyl compound-aromatic polyene copolymer" containing or not containing a cyclic olefin and the resins exemplified as the "resin component." These include hydrocarbon-based elastomers, polyether-based resins having multiple functional groups in one molecule, including polyphenylene ether, and aromatic polyene-based resins. The composition may also contain the "curing agent," "multifunctional monomer component," "monofunctional monomer component," "solvent," "filler," and "other additives." When a solvent is included, the composition may be a varnish. These compositions and varnishes can be formed into uncured or semi-cured molded articles (for example, sheets) by known methods, optionally after a drying process, and then cured under appropriate conditions to obtain a cured product.

[0060] The coefficient of linear expansion (CTE) from 0°C to 200°C of the cured product obtained from the composition of the present invention is preferably 150 ppm or less, more preferably 80 ppm or less. Those skilled in the art can determine the formulation of a composition having the above physical property parameters and produce a cured product by referring to the information described in this specification and publicly available documents. The cured product obtained from the composition of the present invention can exhibit practically sufficient heat resistance and mechanical properties at high temperatures, even under conditions in which the monomer in the composition and the aromatic polyene as a component of the monomer are kept below a certain ratio.

[0061] <Uses of the cured body of the organic crosslinked particles or the composition comprising the organic crosslinked particles and a curable resin> The cured body of the organic crosslinked particles of the present invention or the composition comprising the organic crosslinked particles and a curable resin can be used as a base material or substrate such as a single-layer or multi-layer printed circuit board, a flexible printed circuit board, a so-called single-layer or multi-layer CCL board, a single-layer or multi-layer FCCL, or a single-layer or multi-layer RCC board. It can also be used as various electrical insulating materials for wiring, preferably for high-frequency signal wiring, such as coverlays, high-frequency transmission circuits, antennas, solder resists, build-up materials, interlayer insulating materials, bonding sheets, interlayer adhesives, and bump sheets for flip-chip bonders.

[0062] In one embodiment of the present invention, there is also provided a method for producing the copolymer, which comprises copolymerizing, by coordination polymerization, monomers of an olefin such as an α-olefin or a cyclic olefin, an aromatic vinyl compound, and an aromatic polyene.

[0063] 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 monomer of an olefin such as an α-olefin or a cyclic olefin, an aromatic vinyl compound, 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:

[0064] General formula (1)

[0065] 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.

[0066] 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.

[0067] 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.

[0068] M is a transition metal, and may preferably be zirconium, hafnium, or titanium.

[0069] 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.

[0070] 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.

[0071] Examples of boron compounds 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, and triethylammonium 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 such compounds 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. Although boron-containing promoters in which the fluorine-substituted aromatic group is a phenyl group have been exemplified herein, boron-containing promoters having a fused aromatic group such as a fluorine-substituted naphthyl group can also be preferably used. Among these, the most preferred boron promoters are those having boron and a fluorine-substituted aromatic group bonded thereto. Examples include trispentafluorophenylborane, triphenylcarbenium tetrakis(pentafluorophenyl)borate {trityl tetrakis(pentafluorophenyl)borate}, lithium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetra(pentafluorophenyl)borate, tropylium tetrakispentafluorophenylborate, and N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate. Particularly preferred are triphenylcarbenium tetrakis(pentafluorophenyl)borate {trityl tetrakis(pentafluorophenyl)borate} and N,N'-dimethylanilinium tetrakis(pentafluorophenyl)borate is used. These most preferred boron-containing cocatalysts are sometimes referred to as TRI-FABA or TRI-FAB, DAN-FABA or DAN-FAB, respectively, and can be purchased from Tosoh Finechem Co., Ltd. or Kanto Chemical Co., Ltd.

[0072] 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.

[0073] 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.

[0074] In a preferred embodiment, a co-catalyst containing a boron compound as an essential component and an aluminum compound as an optional component may be used. The use of a boron compound as a co-catalyst can reduce the amount of metal components, such as aluminum derived from the aluminum compound, contained in the final copolymer, and can reduce the values ​​of the dielectric constant and dielectric loss tangent of the final crosslinked organic particles and a cured product of a composition containing the same to particularly preferred ranges, for example, a dielectric constant of 2.5 or less and a dielectric loss tangent of 0.0010 or less.

[0075] In one embodiment, an olefin-aromatic vinyl compound-aromatic polyene copolymer can be provided in which the total content of metals derived from the catalyst and co-catalyst is 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. When organic crosslinked particles are produced using an 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, the properties of a dielectric constant of 2.5 or less and a dielectric loss tangent of 0.0010 or less at 10 GHz can be particularly satisfied.

[0076] 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.

[0077] The method for producing the copolymer used in the present invention is shown in the following Synthesis Examples. The copolymers obtained in the Synthesis Examples were analyzed by the following means. The contents of ethylene, cyclic olefin, styrene, and ethylvinylbenzene in the copolymer, as well as the content of vinyl group units derived from divinylbenzene, were determined by the following methods: 1 H-NMR measurement and quantitative mode 13 C-NMR measurement was performed, and the determination was performed using a known method based on the area intensity of the obtained peaks. The sample was dissolved in heavy 1,1,2,2-tetrachloroethane, and the measurement was performed at 80 to 130°C. In this specification, the copolymer may also be referred to as a "resin."

[0078] <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.

[0079] <Glass Transition Temperature> The glass transition temperature of the organic crosslinked particles was determined by DSC. Using a DSC214 Polymer manufactured by Netzsch, 2.5 mg of sample was weighed out onto an aluminum pan and measured under the following temperature increase conditions in a nitrogen stream. The value obtained in the second run was used. Temperature increase / decrease conditions: 25°C → -50°C: 10°C / min -50°C → 250°C (1st run): 10°C / min 100°C → -50°C: 10°C / min -50°C → 250°C (2nd run): 10°C / min

[0080] <Gel content> The gel content was determined as boiling toluene insoluble matter according to ASTM D2765-84. However, since the organic crosslinked particles pass through the metal mesh, the suspension after the boiling toluene treatment was centrifuged to determine the mass of the insoluble matter, thereby determining the gel content.

[0081] <Dielectric Constant (Dk) and Dielectric Loss (Dielectric Loss Tangent (Df))> The dielectric constant (relative permittivity) and dielectric loss tangent of a single cured product of the olefin-aromatic vinyl compound-aromatic polyene copolymer were measured using a cavity resonator perturbation method (Agilent Technologies 8722ES Network Analyzer, Keysight Technologies 10 GHz Split Cylinder Resonator) at 23°C and 10 GHz using a 0.1 mm x 25 mm x 30 mm sample cut out from the cured sheet. Measurements were made for both the uncured state and the cured state.

[0082] <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, dissolved by heating, and then the volume was adjusted to 5 mL to prepare a test solution. Quantitative analysis was performed by ICP atomic emission spectrometry (using an Agilent 5110VDV).

[0083] <Average Particle Diameter> The average particle diameter (median diameter D50) in this specification was determined using a laser diffraction scattering particle size distribution analyzer "LS-13 320" (product name) manufactured by Beckman Coulter, Inc., in accordance with the description of ISO 13320:2009.

[0084] <I ap Value > IR measurement method I ap Value = I (3025 cm -1 : aromatic C-H expansion / contraction) / I (2920cm -1 : Aliphatic C-H expansion / contraction)

[0085] <Copolymer P-1 (ethylene-styrene-divinylbenzene copolymer)> Ethylene-styrene-divinylbenzene copolymer P-1 was produced according to the production method using the catalyst dimethylmethylenebis(cyclopentadienyl)zirconium dichloride described in WO 2022 / 014599 and the production method using a boron compound as a co-catalyst described in the examples of WO 2017 / 122295.

[0086] Copolymer P-2 (ethylene-norbornene-styrene-divinylbenzene copolymer) The raw material divinylbenzene (DVB) was "Divinylbenzene (81%)" manufactured by Nippon Steel Chemical & Material Co., Ltd. (liquid at room temperature, a mixture of meta and para isomers containing 81% by mass of divinylbenzene, with the remainder being ethylvinylbenzene). Norbornene (75% concentration, toluene solution) manufactured by Maruzen Petrochemical Co., Ltd. was used as the raw material. A small amount of triisobutylaluminum (TIBA) was added beforehand, the mixture was stirred at room temperature, and then distilled and purified under nitrogen. A 10-L polymerization vessel equipped with a heating and cooling jacket and a stirrer was used for the polymerization. The interior of the thoroughly dried polymerization vessel was first purged with nitrogen, and 1.4 kg of toluene, 0.23 kg of pure norbornene, 3.0 kg of styrene, and 0.60 kg of divinylbenzene (81% divinylbenzene) were charged. Approximately 20 L of dry nitrogen was bubbled through the vessel at an internal temperature of 60°C. The inside of the polymerization vessel was then purged with ethylene gas, and 6 mmol of TIBA (manufactured by Kanto Chemical Co., Inc.) was added and stirred. The internal temperature was stabilized at 80°C, and the internal pressure of the polymerization vessel was increased to 0.1 MPaG (gauge) with nitrogen and stabilized. Then, from a catalyst tank installed above the polymerization vessel, a catalyst solution was added to the polymerization vessel, which had been prepared by adding 210 μmol of tritylium tetrakis(pentafluorophenyl)borate to 100 g of a toluene solution containing 200 μmol of dimethylmethylenebis(cyclopentadienyl)zirconium dichloride (formula (1)) as a catalyst and 2 mmol of TIBA, and stirring the solution, and the catalyst solution was added to the polymerization vessel to initiate polymerization. The polymerization was continued while maintaining the internal temperature at 60°C and the internal pressure at 0.1 MPaG (ethylene pressure), and when the ethylene consumption reached 100 g, 50 g of isopropanol (a polymerization terminator) was added to the polymerization vessel to terminate the polymerization. The obtained polymerization liquid was poured little by little into a sufficiently large amount of a methanol / acetone mixed solution, and the precipitated polymer was recovered by stirring and filtering, and the polymer was thoroughly dried in vacuum at room temperature to obtain an ethylene-norbornene-styrene-divinylbenzene copolymer P-2.

[0087] Formula (1)

[0088] <Copolymer P-3 (ethylene-norbornene-styrene-divinylbenzene copolymer)> Similar to P-2, except that 2.0 kg of toluene, 2.0 kg of pure norbornene, 0.80 kg of styrene, and 0.20 kg of divinylbenzene (mass of 81% divinylbenzene product) were charged, and polymerization was continued while maintaining the internal temperature at 90°C and the internal pressure at 0.1 MPaG in ethylene pressure. When the ethylene consumption reached 40 g, 50 g of isopropanol as a polymerization terminator was added to the polymerization vessel to terminate the polymerization. The resulting polymerization solution was poured little by little into a sufficiently large amount of methanol / acetone mixed solution, and the precipitated polymer was recovered by stirring and filtration, and thoroughly vacuum dried at room temperature to obtain ethylene-norbornene-styrene-divinylbenzene copolymer P-3.

[0089] Since P-1, P-2, and P-3 obtained in each Example contained small amounts of residual monomer and solvent, they were redissolved in toluene, and the solution was poured in small amounts into a sufficiently large amount of a 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 composition, molecular weight, and metal contents derived from the catalyst and co-catalyst of the obtained P-1 to P-3 are shown in Table 1. The purified polymer was again dissolved in toluene to obtain a 60% by mass toluene solution (varnish).

[0090] <Preparation and Evaluation of Copolymer Monocurd Products> 0.75% by mass of initiator, relative to the mass of the resin content, was added and dissolved in varnishes containing 60% by mass of each of P-1 to P-3. Perbutyl P was used for P-1, and azo-based initiator VR-110 was used for P-2 and P-3. These varnishes were poured into a Teflon (registered trademark) mold (frame length 7 cm, width 7 cm, thickness 0.2 mm) on a PET sheet placed on a glass plate, thoroughly air-dried at 25°C, and then further dried at 100°C for 3 hours in a vacuum dryer to obtain uncured sheets that were substantially free of solvent. If necessary, multiple uncured sheets were stacked to the required thickness for each measurement. A Teflon sheet was placed on a smooth metal plate, and the uncured sheet was then placed on top of that. A mold of the required thickness, a Teflon sheet, and a smooth metal plate were then placed on top of that. In the case of P-1 and P-2, the sheets were heated in a vacuum press under a load of 5 MPa at 150°C for 30 minutes and then at 200°C for 30 minutes. In the case of P-3, the sheets were heated at 200°C for 30 minutes and then at 250°C for 30 minutes. The Teflon sheet and Teflon mold were then removed to obtain a cured sheet (a sheet cured with the resin alone). The gel fraction, dielectric constant, and dielectric loss tangent of the resulting cured sheet (all measured at 23°C and 10 GHz) were determined. The results are shown in Table 1.

[0091]

[0092] Example 1 (Emulsion Polymerization) A reaction apparatus equipped with a 1 L reaction vessel, a condenser, a stirrer, a stirring blade, a thermometer, and an oil bath was prepared. 250 g of deionized water and 66 g of a 10 wt % aqueous solution of Poval PVA-217 (manufactured by Kuraray) were mixed to prepare an aqueous layer. 22 g of P-1 (pure), 33 g of divinylbenzene (manufactured by Fujifilm Wako Chemical Co., Ltd., m,p isomer mixture, purity as DVB: 93% by mass), 1.3 g of 2,2-azobisisobutyronitrile (AIBN), and 18.4 g of toluene were mixed to prepare an oil layer. The aqueous layer was charged into a 1 L reaction vessel, and while the oil layer was being added, the mixture was emulsified and dispersed for 3 minutes at a rotation speed of 12,000 rpm using a homogenizer emulsifier to obtain a milky white liquid. This milky white liquid was placed in the reactor and gradually heated with stirring until the liquid temperature reached approximately 90°C. The polymerization reaction was then carried out for approximately 4 hours while maintaining the temperature at approximately 90°C. After cooling to room temperature, the mixture was filtered through a filter cloth, yielding an emulsion with a recovered amount of 372 g and a solids content of 14.5% by mass. The emulsion was centrifuged in a centrifuge (centrifugal acceleration 43,200 g) to separate the crosslinked microparticles and the transparent aqueous layer, after which the transparent aqueous layer was removed. A large amount of methanol was added to redisperse the mixture, and the mixture was centrifuged again in the same manner to separate the layers. The methanol layer was then removed. This procedure was repeated several times. The methanol-wetted sample was further diluted with methanol and the average particle size was measured. The mixture was dried at approximately 80°C for approximately half a day to obtain white crosslinked microparticles (powder, organic crosslinked particles 1).

[0093] Example 2 Emulsion polymerization was carried out in the same manner as in Example 1, except that copolymer P-2 was used instead of copolymer P-1, to obtain organic crosslinked particles 2.

[0094] Example 3 Emulsion polymerization was carried out in the same manner as in Example 1, except that the copolymer P-1 used was changed to P-3, the amount of P-3 used was changed to 11 g, and the amount of toluene was changed to 44 g, to obtain organic crosslinked particles 3.

[0095] Example 4 (Emulsion polymerization) Emulsion polymerization was carried out in the same manner as in Example 3, except that copolymer P-3 was used, 2,2-azobisisobutyronitrile (AIBN) was changed to 0.11 g, and the liquid temperature was changed to 80° C., to obtain an emulsion with a recovered amount of approximately 390 g and a solid content of 11.6 mass %. Post-treatment was carried out in the same manner as in the example, to obtain organic crosslinked particles 4.

[0096]

[0097] The median diameter, gel content, and I of the obtained organic crosslinked particles ap The values ​​of the crosslinked organic particles and the glass transition temperatures measured by DSC are shown in Table 2. A TEM photograph of the organic crosslinked particles 1 obtained in Example 1 is also shown ( FIG. 1 ). For 30 organic crosslinked particles within the field of view of the TEM photograph, the minimum diameter was within −20% of the maximum diameter in three dimensions. That is, when the longest and shortest diameters of the particles were compared in the TEM image, the minimum diameter was within −20% of the maximum diameter.

[0098] The gel content of each organic cross-linked particle was sufficiently high, indicating that cross-linking had progressed. Furthermore, powdered P-1 was heated and pressurized in a hot press at 5 MPa and 200°C for 1 hour, but no melting of the powder was observed, also indicating that cross-linking had progressed sufficiently.

[0099] Median diameter, I ap The Tg value also fell within the range of the present invention. The Tg value was higher than that of the raw material olefin-aromatic vinyl compound-aromatic polyene copolymer cured alone.

[0100] (Dielectric Properties of Crosslinked Organic Particles) Then, for Example 4, the dielectric properties of the crosslinked organic particles 4 were measured. The measurement was performed in accordance with JIS C2565 using a 10 GHz cylindrical cavity resonator and a Keysight P9373B network analyzer at 10 GHz and 23°C. The dielectric constant and dielectric loss tangent of the crosslinked organic particles 4 were determined using the true specific gravity and bulk specific gravity of the crosslinked organic particles 4, which were measured separately. As a result, the dielectric constant was 2.1 and the dielectric loss tangent was 0.0009.

[0101] The organic crosslinked particles of the present invention have excellent low dielectric properties and high Tg, and are useful as additives to various low dielectric curable materials.

Claims

1. Organic crosslinked particles comprising an olefin-aromatic vinyl compound-aromatic polyene copolymer.

2. The organic crosslinked particles according to claim 1, having a median diameter D50 in the range of 0.1 to 5.0 μm.

3. The organic crosslinked particle of claim 1 further comprising a polyfunctional monomer.

4. IR measurement of I (3025 cm -1 : aromatic C-H expansion / contraction) / I (2920cm -1 2. The organic crosslinked particle of claim 1, wherein the aliphatic C-H stretch (aliphatic C-H stretch) is 0.10 or greater and 1.20 or less.

5. The organic crosslinked particles according to claim 1, which have a gel content of 80% by mass or more.

6. The organic crosslinked particles according to claim 1, which have a glass transition temperature (Tg) measured by DSC of 100°C or higher and 350°C or lower.

7. The organic crosslinked particles according to claim 1, wherein the olefin-aromatic vinyl compound-aromatic polyene copolymer satisfies all of the following (1) to (5): (1) the number-average molecular weight of the copolymer is 500 to 50,000; (2) the aromatic vinyl compound monomer is an aromatic vinyl compound having 8 to 20 carbon atoms, and the content of the aromatic vinyl compound monomer unit is 0.1 to 70 mass%; (3) the olefin monomer unit is one or more selected from α-olefin monomer units having 2 to 30 carbon atoms and cyclic olefin monomer units having 7 to 30 carbon atoms, and the content thereof is 5 to 95 mass%; (4) the aromatic polyene monomer is one or more selected from polyenes having 5 to 20 carbon atoms and having multiple vinyl groups and / or vinylene groups in the molecule, and the content of vinyl groups and / or vinylene groups derived from the aromatic polyene monomer units is 2 to 30 per number-average molecular weight. (5) The total amount of the olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass.

8. The organic crosslinked particles according to claim 1, wherein the olefin is an olefin-aromatic vinyl compound-aromatic polyene copolymer containing at least a cyclic olefin component.

9. The organic crosslinked particles according to claim 1, which are olefin-aromatic vinyl compound-aromatic polyene copolymers exhibiting a dielectric constant of 2.5 or less and a dielectric loss tangent of 0.0010 or less, measured at 10 GHz and 23°C.

10. The method for producing organic crosslinked particles according to any one of claims 1 to 9, wherein the olefin-aromatic vinyl compound-aromatic polyene copolymer and a polyfunctional monomer are polymerized by emulsion polymerization.

11. A composition comprising the organic crosslinked particles of any one of claims 1 to 9.

12. The composition of claim 11, further comprising a curable resin.

13. The composition according to claim 12, wherein the curable resin is one or more selected from the group consisting of olefin-aromatic vinyl compound-aromatic polyene copolymers, hydrocarbon elastomers, polyether resins having multiple functional groups in one molecule, including polyphenylene ether, and aromatic polyene resins.

14. A cured product of the composition according to claim 11.

15. The cured product according to claim 14, which is in the form of a sheet.

16. The cured product according to claim 14, having a coefficient of linear expansion (CTE) of 150 ppm or less from 0°C to 200°C.

17. A CCL, FCCL, interlayer insulation, or RCC comprising the organic crosslinked particles of any one of claims 1 to 9.

18. A CCL, FCCL, interlayer insulation material, or RCC comprising the cured product of claim 14.

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