WO2025075056A1 - Composition and cured product thereof - Google Patents

Abstract

The present disclosure provides: a method for obtaining a cured body containing an epoxy compound and a resin having an aromatic vinyl group as a functional group; an epoxy resin-based composition and a cured body thereof, having improved low dielectric performance; and an electrically insulating material and the like. The present disclosure provides: a composition that contains an epoxy compound, a resin having an aromatic vinyl group as a functional group, and an active vinyl compound; a cured body of the composition; and an electrically insulating material. The resin having an aromatic vinyl group as a functional group is preferably an olefin-aromatic vinyl compound-aromatic polyene copolymer. The active vinyl compound is preferably one or more compounds selected from the group consisting of a maleimide compound and a cyanate compound.

Description

Composition and cured product thereof

The present invention relates to compositions containing epoxy compounds, resins having aromatic vinyl groups as functional groups, and active vinyl compounds, as well as their cured bodies and electrical insulating materials.

As communication frequencies move to the gigahertz band and especially to the millimeter wave band of 30 GHz or more, the demands for low dielectric properties of insulating materials made of CCL or FCCL used in multilayer boards, transmission lines, antennas, etc. are becoming more stringent and advanced. Fluorine-based resins such as perfluoroethylene have the characteristics of excellent low dielectric constant, low dielectric loss, and excellent heat resistance, but they are difficult to mold and form into films, and there are also issues with adhesion to the copper foil of wiring, making them difficult to apply to multilayer boards, etc. On the other hand, boards and insulating materials using post-curing resins such as epoxy resin, unsaturated polyester resin, polyimide resin, and phenol resin have been widely used due to their heat resistance and ease of handling, but their dielectric constant and dielectric loss are relatively high, and improvements are needed as insulating materials for high frequencies.

Therefore, attention has been focused on hydrocarbon-based resins that have inherently low dielectric properties. In order to make hydrocarbon-based resins, which are essentially thermoplastic resins, into curable resins, it is necessary to introduce functional groups. However, functional groups that undergo crosslinking reactions with radicals or heat generally have polarity, so introducing these functional groups into hydrocarbon-based resins will deteriorate the dielectric properties. When attempting to introduce functional groups composed only of hydrocarbons, such as aromatic vinyl groups, in many cases expensive intermolecular reactions between hydrocarbon-based monomers are used (Patent Document 1), which is often not economical. A cured body consisting of an ethylene-olefin (aromatic vinyl compound)-aromatic polyene copolymer and a non-polar vinyl compound copolymer, which are obtained from a specific coordination polymerization catalyst and have a specific composition and blend, has been proposed. Only one of the two aromatic vinyl groups of the aromatic polyene (divinylbenzene) unit in this copolymer is selectively copolymerized, and the remaining aromatic vinyl group is preserved, so that a crosslinkable hydrocarbon-based copolymer macromonomer having an aromatic vinyl group functional group can be easily obtained. The cured body obtained from the composition of this olefin-aromatic vinyl compound-aromatic polyene copolymer and auxiliary materials, etc., has the characteristics of a low dielectric constant and a low dielectric loss tangent (Patent Documents 2, 3, 4). Furthermore, dendritic copolymers having aromatic vinyl groups as functional groups, obtained by copolymerizing styrene monomers and aromatic polyene (divinylbenzene) by cationic polymerization, have also been proposed (Patent Document 5). However, although these copolymers have excellent low dielectric properties, they do not react with the epoxy resins that are widely used in this insulating material, and it has been thought that it is difficult to use them as additives to epoxy resins.

JP 2004-087639 A International Publication No. 2021/112087 International Publication No. 2021/112088 International Publication No. 2022/014599 International Publication No. 2018/181842

The present invention provides a method for obtaining a cured product containing an epoxy compound and a resin having an aromatic vinyl group as a functional group, an epoxy resin composition with improved low dielectric performance, a cured product thereof, and an electrical insulating material, etc.

As a result of extensive research into solving the above problems, the inventors have come up with the idea of solving the above problems and have completed the present invention. That is, the present invention is a resin composition containing an epoxy compound, a resin having an aromatic vinyl group as a functional group, and an active vinyl compound, as well as a cured body made of this resin composition, an electrical insulating material, etc. The present invention provides various specific aspects as shown below.

Aspect 1.
A composition comprising an epoxy compound, a resin having an aromatic vinyl group as a functional group, and an active vinyl compound.

Aspect 2.
The composition according to embodiment 1, wherein the resin having an aromatic vinyl group as a functional group is an olefin-aromatic vinyl compound-aromatic polyene copolymer.

Aspect 3.
3. The composition of claim 1 or 2, wherein the active vinyl compound is one or more compounds selected from the group consisting of maleimide compounds and cyanate compounds.

Aspect 4.
The composition of any one of Aspects 1 to 3, further comprising a compound having a plurality of functional groups, at least one of which is selected from the group consisting of an amino group, a phenolic hydroxyl group, a carboxyl group, a carboxylic anhydride group, and the like.

Aspect 5.
The composition according to any one of Aspects 2 to 4, wherein the olefin-aromatic vinyl compound-aromatic polyene copolymer satisfies all of the following conditions (1) to (4):
(1) The number average molecular weight of the copolymer is 500 or more and less than 30,000.
(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 to 98 mass %.
(3) The aromatic polyene monomer is one or more selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and/or vinylene groups in the molecule, and the content of the vinyl groups and/or vinylene groups derived from the aromatic polyene monomer units is 2 to 30 per number average molecular weight.
(4) One or more olefin monomer units having 2 to 20 carbon atoms may be contained, and when the aromatic vinyl compound monomer unit and the aromatic polyene monomer unit are present, the total amount of the olefin monomer units and the aromatic vinyl compound monomer units is 100 mass% in terms of solid content.

Aspect 6.
A cured product obtained from the composition according to any one of Aspects 1 to 5.

Aspect 7.
The cured product of embodiment 6, which is an electrical insulating material.

Aspect 8.
A CCL substrate, an FCCL substrate, an interlayer insulating material, or a coverlay, comprising the cured product according to embodiment 6 or 7.

The present invention provides an epoxy resin composition and an epoxy cured product with excellent low dielectric properties, as well as electrical insulating materials. The composition and the cured product are useful as insulating materials for high frequency applications, particularly for multilayer printed circuit boards.

Hereinafter, the embodiments of the present invention will be described in detail. However, the following embodiments are merely examples for explaining the present invention, and the present invention is not limited to these. In other words, the present invention can be modified and carried out as desired without departing from the scope of the present invention.
The composition according to the present embodiment will be described in more detail below. In this specification, the term "sheet" also includes the concept of a film. In addition, even if the term "film" is used in this specification, the term "sheet" also includes the concept of a sheet. In this specification, the term "composition" includes the concept of a varnish. That is, a composition that is particularly liquid is described as a varnish. In this specification, the term "interlayer insulating material" includes the concept of a bonding sheet or an interlayer adhesive. An epoxy compound is a compound having one or more epoxy groups in its molecule, and may also be referred to as an epoxy prepolymer or simply an epoxy resin. There is no limit to its molecular weight, and polymer compounds are also included. In addition, an active vinyl compound is a compound having one or more active vinyl groups in its molecule, and there is no limit to its molecular weight, and polymer compounds are also included.

In this specification, unless otherwise specified, a numerical range includes its lower limit and upper limit. For example, a numerical range expressed as "1 to 100" includes both the lower limit "1" and the upper limit "100". The same applies to other numerical range expressions.

The resin composition (composition) provided by one embodiment of the present invention is a resin composition that includes an epoxy compound, a resin having an aromatic vinyl group as a functional group, and an active vinyl compound.

Here, the epoxy compound may be a known compound or polymer material having multiple epoxy groups in the molecule, which is used as an insulating material for conventional substrates. Any of the conventionally known epoxy compounds (resins) may be used as such an epoxy compound. Examples of the epoxy compound include, but are not limited to, bisphenol A type, bisphenol F type, phenol novolac type, cresol novolac type, biphenyl novolac type, phenol aralkyl type, biphenyl aralkyl type, aliphatic type, and various amine types. Biphenyl aralkyl type epoxy compounds having a biphenyl aralkyl skeleton are preferred. For example, biphenyl aralkyl type epoxy resins described in paragraphs 0007 to 0098 of International Publication No. 2010-061980 are particularly preferred examples, and the entire contents of the International Publication are incorporated herein by reference.

Resins having an aromatic vinyl group (styryl group) as a functional group include, but are not limited to, olefin-aromatic vinyl compound-aromatic polyene copolymers, polyether resins having a styryl group (including polyphenylene ether and polyether ketone), etc. Such polymers are available from Mitsubishi Gas Chemical Company, Inc. under the product name "OPE-2St", and aromatic polyethers (ELPAC HC-F series) from JSR Corporation can also be used suitably. In addition, dendritic copolymers having an aromatic vinyl group as a functional group (Nippon Steel Chemical & Material Co., Ltd. ODV or PDV) obtained by copolymerizing an aromatic vinyl compound (styrene, ethylvinylbenzene, etc.) with an aromatic polyene compound (divinylbenzene) by cationic polymerization as described in WO 2018/181842 can also be used suitably. The number average molecular weight of the resin having an aromatic vinyl group (styryl group) as a functional group is preferably 500 or more and less than 30,000.

An active vinyl compound is a compound having one or more active vinyl groups in the molecule. Here, the active vinyl group refers to a vinyl group that can react with an aromatic vinyl group and an epoxy group, and specifically includes a maleimide group or a cyanate group. Specific examples of active vinyl compounds include maleimide compounds and cyanate compounds. It is preferable that the active vinyl compound is not a resin having an aromatic vinyl group as a functional group. As the maleimide compound that can be used in this embodiment, known compounds and polymer materials (maleimide resins) having one or more maleimide groups in the molecule, which are used as insulating materials for conventional substrates, can be used. Such maleimides are described, for example, in International Publication No. 2016/114287, JP 2008-291227 A, and International Publication No. 2020/054601. In particular, the maleimide resin described in paragraphs 0009 to 0097 of International Publication No. 2020/054601 is preferred, and all of the contents of this international publication are incorporated herein by reference. Maleimide compounds and maleimide resins can be purchased from, for example, Daiwa Kasei Kogyo Co., Ltd., Nippon Kayaku Co., Ltd., and Designer Molecules Inc. Also, bismaleimide resin "SLK" manufactured by Shin-Etsu Chemical Co., Ltd. can be used. These maleimides are preferably bismaleimides from the viewpoints of solubility in organic solvents, high frequency characteristics, high adhesion to conductors, moldability of prepregs, etc. These maleimides may be used as polyamino bismaleimide compounds from the viewpoints of solubility in organic solvents, high frequency characteristics, high adhesion to conductors, moldability of prepregs, etc. Polyamino bismaleimide compounds can be obtained, for example, by subjecting a compound having two maleimide groups at the terminals to a Michael addition reaction with an aromatic diamine compound having two primary amino groups in the molecule. Cyanate compounds are also referred to as cyanate ester compounds and are described, for example, in JP 2006-124494 A, WO 2011/083818 A, and WO 2013/021869 A, and are supplied by Mitsubishi Gas Chemical Company, Inc. as BT resin, a resin containing a cyanate compound.

<Olefin-Aromatic Vinyl Compound-Aromatic Polyene Copolymer>
The olefin-aromatic vinyl compound-aromatic polyene copolymer, which can be most suitably used as a resin having an aromatic vinyl group (styryl group) as a functional group, is a copolymer obtained by copolymerizing an olefin (olefin monomer), an aromatic vinyl compound (aromatic vinyl compound monomer), and an aromatic polyene (aromatic polyene monomer). The olefin-aromatic vinyl compound-aromatic polyene copolymer may be abbreviated as "copolymer". Furthermore, each monomer in the copolymer may be referred to as an olefin monomer unit, an aromatic vinyl compound monomer unit, and an aromatic polyene monomer unit, respectively. The copolymer may be a copolymer that satisfies all of the following conditions (1) to (3), and preferably a copolymer that satisfies all of the following conditions (1) to (4).
(1) The number average molecular weight of the copolymer is 500 or more and 30,000 or less, preferably 500 or more and less than 30,000. In this specification, the number average molecular weight (Mn) is calculated as a molecular weight calculated based on standard polystyrene obtained by GPC (gel permeation chromatography). More specifically, the method and conditions described in the examples are followed.
(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 to 70 mass %.
(3) The aromatic polyene monomer is one or more selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and/or vinylene groups in the molecule, and the content of the vinyl groups and/or vinylene groups derived from the aromatic polyene monomer units is 2 or more and less than 30 per number average molecular weight.
(4) One or more olefin monomer units having 2 to 20 carbon atoms may be contained, and when an aromatic vinyl compound monomer unit and an aromatic polyene monomer unit are present, the total of the olefin monomer units and the aromatic vinyl compound monomer units is 100 mass%.

In the present copolymer, the olefin monomer is one or more selected from α-olefins having 2 to 20 carbon atoms and cyclic olefins having 5 to 20 carbon atoms. The olefin monomer is preferably a compound that is substantially free of oxygen, nitrogen, and halogens and is composed of carbon and hydrogen (i.e., a compound that is 99% by mass or more composed of carbon and hydrogen, and preferably composed only of carbon and hydrogen). Examples of α-olefins having 2 to 20 carbon atoms include, but are not limited to, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene. Examples of cyclic olefins having 5 to 20 carbon atoms include, but are not limited to, norbornene and cyclopentene. The olefin monomer that can be preferably used is a combination of ethylene with an α-olefin other than ethylene or a cyclic olefin, or ethylene alone.

Aromatic polyene monomers are polyenes having 5 to 20 carbon atoms and having multiple vinyl and/or vinylene groups in the molecule. The aromatic polyene monomers may preferably be ortho-, meta-, or para-variable divinylbenzenes or mixtures thereof, or those having an aromatic vinyl structure such as divinylnaphthalene, divinylanthracene, p-2-propenylstyrene, or p-3-butenylstyrene. The aromatic polyene monomers are preferably compounds substantially free of oxygen, nitrogen, or halogens and composed of carbon and hydrogen (i.e., compounds consisting of 99% by mass or more of carbon and hydrogen, preferably consisting only of carbon and hydrogen). In addition, bifunctional aromatic vinyl compounds described in JP-A-2004-087639, such as 1,2-bis(vinylphenyl)ethane (abbreviation: BVPE), can also be used as aromatic polyene monomers. Among these, ortho-, meta-, or para-variable divinylbenzenes or mixtures thereof are preferably used, and most preferably a mixture of meta- and para-divinylbenzene is used. In this specification, these divinylbenzenes are referred to as divinylbenzenes. When divinylbenzenes are used as aromatic polyenes, the curing efficiency is high and curing is easy during the curing process.

The content of aromatic vinyl compound monomer units contained in the copolymer may be 0% by mass or more and 70% by mass or less, preferably 1% by mass or more and 70% by mass or less, and more preferably 10% by mass or more and 70% by mass or less. When the content of aromatic vinyl compound monomer units is 70% by mass or less, at least one of the glass transition temperatures of the cured product of the final composition is lower than near room temperature, which is preferable because it can improve toughness and elongation at low temperatures. When the content of aromatic vinyl compound monomer units is 1% by mass or more, more preferably 10% by mass or more, the aromaticity of the copolymer is improved, the compatibility with flame retardants and fillers is improved, bleeding out of flame retardants can be avoided, and the filling property of fillers can be improved. When the content of aromatic vinyl compound monomer units is 1% by mass or more, more preferably 10% by mass or more, it is easy to obtain a cured product of the composition with high adhesive strength to copper foil and copper wiring.

In the copolymer, the content of vinyl groups and/or vinylene groups derived from aromatic polyene monomer units, preferably the content of vinyl groups, may be 2 or more and 30 or less, more preferably 20 or less or less than 20, and even more preferably 3 or more and 20 or less or 3 or more and less than 20 per number average molecular weight. When the content of vinyl groups and/or vinylene groups is 2 or more, crosslinking efficiency is high, and a cured product with sufficient crosslinking density tends to be easily obtained. The vinyl group content derived from aromatic polyene units (divinylbenzene units) per number average molecular weight in the copolymer can be obtained, for example, by comparing the number average molecular weight (Mn) calculated in terms of standard polystyrene obtained by GPC (gel permeation chromatography) method known to those skilled in the art with the composition obtained by ¹ H-NMR measurement and/or ¹³ C-NMR measurement measured in quantitative mode and the vinyl group content derived from aromatic polyene units. Such a method is obvious and well known to those skilled in the art. Also possible are methods described in the patent documents in the prior art literature of this specification.

In the copolymer, the content of the olefin monomer unit is preferably 10% by mass or more, more preferably 20% by mass or more. The total of the olefin monomer unit, aromatic vinyl compound monomer unit, and aromatic polyene monomer unit is 100% by mass. When the olefin monomer unit is ethylene and an α-olefin other than ethylene or ethylene alone, the content of the olefin monomer unit is preferably 10% by mass or more, more preferably 30% by mass or more, and most preferably 50% by mass or more. In such a case, the toughness (elongation) and impact resistance of the finally obtained cured body are improved, and cracks during curing or cracks during heat cycle testing of the cured body tend to be less likely to occur. Also, when the olefin monomer unit is ethylene and a cyclic olefin or a cyclic olefin alone, the content of the cyclic olefin monomer unit is preferably 30% by mass or more, more preferably 50% by mass or more, and most preferably 70% by mass or more. In such cases, the glass transition temperature of the final cured product can be set to 100°C or higher, preferably 150°C or higher, and most preferably 180°C or higher, which tends to make it easier to obtain a cured product with excellent heat resistance.

Examples of the olefin-aromatic vinyl compound-aromatic polyene copolymer include, but are not limited to, ethylene-styrene-divinylbenzene copolymer, ethylene-1-octene-divinylbenzene copolymer, ethylene-norbornene-divinylbenzene copolymer, ethylene-propylene-styrene-divinylbenzene copolymer, ethylene-1-hexene-styrene-divinylbenzene copolymer, ethylene-1-octene-styrene-divinylbenzene copolymer, ethylene-divinylbenzene copolymer, ethylene-norbornene-divinylbenzene copolymer, norbornene-divinylbenzene copolymer, norbornene-styrene-divinylbenzene copolymer, and the like.

In the resin composition, the content of the epoxy compound, active vinyl compound, and resin having an aromatic vinyl group as a functional group (for example, an olefin-aromatic vinyl compound-aromatic polyene copolymer) is arbitrary depending on the composition and structure, but preferably, when the total of these three types is taken as 100 mass%, the content of the epoxy compound is 5 mass% to 50 mass%, the content of the active vinyl compound is 30 mass% to 80 mass%, and the content of the resin having an aromatic vinyl group as a functional group (for example, an olefin-aromatic vinyl compound-aromatic polyene copolymer) is in the range of 5 mass% to 50 mass%.

In addition to the above components, the resin composition preferably contains a curing agent. By including a curing agent, curing can be efficiently promoted. As such a curing agent, it is preferable to use a known curing agent used for curing epoxy compounds. Specifically, examples include amine-based curing agents, phenol-based curing agents, carboxylic acid-based curing agents, and carboxylic acid anhydride-based curing agents, which are compounds having multiple functional groups such as amino groups, phenolic hydroxyl groups, carboxyl groups, and carboxylic acid anhydride groups, but are not limited to these. In addition, active ester-based curing agents and imidazole-based curing agents, which are particularly useful for the effects of epoxy compounds, can also be used as curing agents. The amount of such known curing agents used for curing epoxy compounds and maleimide compounds is not particularly limited, but is preferably in the range of 5 to 50 parts by mass, based on 100 parts by mass of the resin composition.

In addition to the above-mentioned curing agents, the curing agent usable in the present resin composition may be a radical polymerization initiator (radical generator), a cationic polymerization initiator, or an anionic polymerization initiator, which are useful for curing aromatic vinyl groups. Preferably, a radical polymerization initiator may be used, but the type is not particularly limited. More preferably, an organic peroxide-based (peroxide) or an azo-based polymerization initiator may be used, and may be freely selected depending on the application and conditions. A catalog listing organic peroxides can be downloaded from the NOF Corporation website, for example, https://www.nof.co.jp/product-search/family/1020001. Curing by radiation or electron beams themselves is also possible. In addition, aromatic vinyl groups can be crosslinked and cured by thermal polymerization of the raw materials contained therein, even without using a curing agent. There is no particular limit to the amount of curing agent used to cure aromatic vinyl groups, but generally, 0.01 to 10 parts by mass is preferred for 100 parts by mass of the varnish of this embodiment. When using a curing agent such as a peroxide or azo-based polymerization initiator, the curing process should be carried out at an appropriate temperature and time, taking into consideration the half-life of the curing agent. In this case, the conditions can be determined according to the curing agent, but a temperature range of about 50°C to 200°C is generally appropriate.

<Solvent>
An appropriate solvent may be added to the composition of the present embodiment as necessary. The amount of the solvent is not particularly limited. The solvent is used to adjust the viscosity and fluidity of the composition. In particular, when the resin composition of the present embodiment is in the form of a varnish, a solvent is preferably used. As the solvent, a solvent having a boiling point of a certain degree or higher is preferable because a high boiling point under atmospheric pressure, i.e., low volatility, leads to a uniform thickness of the applied film. The boiling point is preferably about 75° C. or higher under atmospheric pressure, more preferably 100° C. or higher and 300° C. or lower, and even more preferably 130° C. or higher and 300° C. or lower. As the solvent, a solvent known in the art can be used, and is not particularly limited. For example, cyclohexane, cyclohexanone, methyl ethyl ketone (MEK), toluene, ethylbenzene, xylene, mesitylene, tetralin, acetone, limonene, mixed alkanes, mixed aromatic solvents, etc. can be used. The amount of the solvent used in the composition of the present embodiment can be appropriately set depending on the desired performance, and is arbitrary, but is preferably 5 to 500 parts by mass, more preferably 10 to 300 parts by mass, and most preferably 50 to 150 parts by mass, relative to 100 parts by mass of the copolymer.

The composition of this embodiment may contain additives that are commonly used in resins in the industry, such as antioxidants, weathering agents, light stabilizers, lubricants, compatibilizers, and antistatic agents, to the extent that the desired effects and purposes are not impaired. The composition and varnish of this embodiment are obtained by mixing and dissolving the various raw materials and additives described above, and any known method can be used for mixing and dissolving.

<Molded body>
The shape of the molded article obtained from the composition of this embodiment is arbitrary. These compositions can exhibit the properties of thermoplastic resins. Therefore, under conditions that do not cause crosslinking, they can be molded into shapes such as chips, sheets, tubes, strips, pellets, etc. in a substantially uncured state by known molding methods for thermoplastic resins, such as extrusion molding, injection molding, press molding, transfer molding, inflation molding, etc., and then crosslinked (cured).

The shape of the molded body and the cured body obtained from the composition of this embodiment, particularly the varnish, is arbitrary. For example, it can be applied to a substrate, or impregnated into a cloth such as glass fiber, a nonwoven fabric, or a porous substrate, and then laminated and covered with copper foil or a substrate, heated and cured under a press, to form a single-layer or multi-layer substrate. The varnish of this embodiment and the molded body obtained from it can be cured by a known method, referring to the curing conditions (temperature, time, pressure) of the raw materials and curing agent contained therein. When the curing agent used is a peroxide, the curing conditions can be determined by referring to the half-life temperature disclosed for each peroxide. Curing may be in one stage or multiple stages. In particular, by performing curing in multiple stages, a molded body (prepreg) in a semi-cured state can be formed in the middle. In particular, the sheet may be in a semi-cured state to the extent that the sheet shape can be maintained, or it may be completely cured after lamination with another substrate or copper foil. Examples of methods for achieving a semi-cured state include using multiple curing agents with different half-life temperatures by adjusting the amounts used, appropriately adjusting the curing time and/or curing temperature, or changing the curing mode (e.g., semi-curing is light curing and full curing is performed with peroxide). It is also possible to use a conventional solvent drying process for such a semi-curing process. Alternatively, when curing by heating and pressurizing using a press or the like, it is possible to introduce a semi-cured state in the middle of this process by multi-stage heating conditions, thereby suppressing the bleeding of varnish and the occurrence of uneven thickness. The degree of curing of the molded product, especially the sheet, can be quantitatively measured by known dynamic mechanical analysis (DMA) or gel content.

<Substrate for impregnation>
The substrate to be impregnated with the varnish of this embodiment may be a known fiber substrate such as glass fiber, polyamide fiber, or alumina fiber. The use of various coupling agents to improve the affinity with these fibers is also known. In addition, fluororesins such as porous PTFE may also be used.

<Cured product and molded product obtained from the composition of the present embodiment>
The cured product obtained from the composition of this embodiment is sufficiently cured, and the gel content measured according to ASTM is preferably 90% by mass or more. The dielectric constant of the cured product at 10 GHz is preferably 5.0 or less and 2.0 or more, more preferably 4 or less and 2.0 or more, and most preferably 3.5 or less and 2.0 or more. The dielectric tangent is preferably 0.03 or less and 0.001 or more, and more preferably 0.01 or less and 0.001 or more. Compared to a composition containing an epoxy and an active vinyl compound that does not contain a resin having an aromatic vinyl group as a functional group, a composition containing an epoxy and an active vinyl compound that contains a resin having an aromatic vinyl group as a functional group can exhibit a sufficient degree of crosslinking and a lower dielectric constant and a lower dielectric tangent value. Thus, the cured product obtained from the composition of this embodiment is particularly preferable as an electrical insulating material for high frequencies, for example, 3 GHz or more, due to its low dielectric tangent value.

The cured product obtained from the composition of this embodiment is particularly suitable as an electrical insulating material for high frequency signals, and these cured products can be suitably used for CCL substrates, FCCL substrates, interlayer insulating materials, or coverlays. This embodiment can also provide CCL substrates, FCCL substrates, interlayer insulating materials, or coverlays made from this copolymer or a composition containing the copolymer. The cured product obtained from the composition of this embodiment has a high crosslink density, and is therefore considered to be particularly useful as an insulating material for package substrates.

The present invention will be explained below with reference to examples, but the present invention should not be interpreted as being limited to the following examples.

The olefin-aromatic vinyl compound-aromatic polyene copolymers obtained in the Synthesis Examples and Comparative Synthesis Examples were analyzed by the following means. The content of vinyl group units derived from ethylene, styrene, and divinylbenzene in the copolymer was determined by a known method using ¹ H-NMR and, if necessary, quantitative mode ¹³ C-NMR measurement in combination from the peak area intensity assigned to each structure. The sample was dissolved in deuterated 1,1,2,2-tetrachloroethane, and the measurement was performed at 80 to 130°C.

The molecular weight of the copolymer was determined by gel permeation chromatography (GPC) to determine the number average molecular weight (Mn) in terms of standard polystyrene. The measurements were performed under the following conditions.

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

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

<Dielectric constant and dielectric loss (dielectric tangent)>
The dielectric constant and dielectric loss tangent of the cured composition were measured using a cavity resonator perturbation method (Agilent Technologies' 8722ES network analyzer, Kanto Electronics Application Development's cavity resonator) at 23° C. and 10 GHz using a 1 mm × 1.5 mm × 80 mm sample cut out from a composition sheet.

<Synthesis Example: Production of Copolymer P-1>
With reference to the manufacturing method described in JP 2009-161743 A, JP 2010-280771 A, and WO 2022/014599, rac diphenylmethylene (1-indenyl) (cyclopentadienyl) zirconium dichloride (see formula (1) below for structure) and MMAO (modified methylaluminoxane, manufactured by Toso Finechem Co., Ltd.) were used as a catalyst, toluene was used as a solvent, and styrene, divinylbenzene, and ethylene were used as raw materials. Polymerization was performed using a polymerization tank with a capacity of 10 L, a stirrer, and a heating and cooling jacket to obtain a polymerization liquid. The obtained polymerization liquid was poured into a sufficient amount of methanol in small amounts at a time, stirred and decanted to obtain a copolymer, and the obtained copolymer was spread thinly in a bat and thoroughly vacuum dried at room temperature to obtain a semi-solid ethylene-styrene-divinylbenzene copolymer P-1. The composition and molecular weight of the obtained P-1 are shown in Table 1.

　重合に用いたジビニルベンゼン（ＤＶＢ）は、日鉄ケミカル＆マテリアル社製の商品名「ジビニルベンゼン（９６％）」（室温で液状、メタ体とパラ体の混合物でジビニルベンゼンを９６質量％含む、残部はエチルビニルベンゼンである）を用いた。

The divinylbenzene (DVB) used in the polymerization was “Divinylbenzene (96%)” (a product name manufactured by Nippon Steel Chemical & Material Co., Ltd., which is liquid at room temperature and is a mixture of meta and para isomers containing 96% by mass of divinylbenzene, with the remainder being ethylvinylbenzene)

Other raw materials used in the composition include NC-3000-L (manufactured by Nippon Kayaku Co., Ltd.) as an epoxy compound, MIR-3000-70MT (manufactured by Nippon Kayaku Co., Ltd.) as a maleimide compound, Kayahard GPH-65 (manufactured by Nippon Kayaku Co., Ltd.) as a phenylaralkyl type phenolic resin as hardener 1, and Perbutyl P (manufactured by NOF Corp.) as hardener 2.

<Examples 1 and 2>
A vessel equipped with a heating and cooling jacket and stirring blades was used, and a mixture (50% by mass/50% by mass) of toluene and MEK (methyl ethyl ketone) was charged as a solvent, and P-1 (ethylene-styrene-divinylbenzene copolymer) obtained in the synthesis example, epoxy compound NC-3000-L, maleimide compound MIR-3000-70MT, phenylaralkyl-type phenolic resin Kayahard GPH-65, and Perbutyl P were stirred and mixed to dissolve in the formulations shown in Table 2. The resulting composition was poured into a Teflon (registered trademark) mold (frame length 7 cm, width 7 cm, thickness 0.2 mm, 0.5 mm, or 3.0 mm) on a PET sheet placed on a glass plate, thoroughly air-dried at 25 ° C., and then further dried in a vacuum dryer at 60 ° C. for 3 hours or more to obtain an uncured sheet. The uncured sheet was then placed in a press with a Teflon sheet and a Teflon frame of a given thickness, pressurized at 5 MPa, and heated at 150° C. for 30 minutes and then at 200° C. for 120 minutes, after which the Teflon sheet and the Teflon frame were removed to obtain a cured sheet. Measurement samples were cut out from the resulting cured sheets of various thicknesses, and the gel content, dielectric constant, and dielectric loss tangent were measured.

<Comparative Example 1>
A cured sheet was prepared in the same manner as in Example 1, except that P-1 (ethylene-styrene-divinylbenzene copolymer) was not used, and the same measurements were carried out.

Table 2 shows the gel content, dielectric constant, and dielectric dissipation factor of the cured products (cured sheets, cured bodies) obtained in each Example and Comparative Example. The cured sheets obtained in the Examples showed a high gel content and were sufficiently cured, and also showed the low dielectric constant and low dielectric dissipation factor required for high-frequency insulating materials. The dielectric constant and dielectric dissipation factor were also lower than those of the Comparative Example, which did not use ethylene-styrene-divinylbenzene copolymer.

Claims (9)

A composition containing an epoxy compound, a resin having an aromatic vinyl group as a functional group, and an active vinyl compound. The composition according to claim 1, wherein the resin having an aromatic vinyl group as a functional group is an olefin-aromatic vinyl compound-aromatic polyene copolymer. The composition according to claim 1, wherein the active vinyl compound is one or more compounds selected from the group consisting of maleimide compounds and cyanate compounds. The composition according to claim 1, further comprising a compound having one or more functional groups selected from the group consisting of amino groups, phenolic hydroxyl groups, carboxyl groups, carboxylic anhydride groups, etc. The composition according to claim 2, wherein the olefin-aromatic vinyl compound-aromatic polyene copolymer satisfies all of the following conditions (1) to (4):
(1) The number average molecular weight of the copolymer is 500 or more and less than 30,000.
(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 to 98 mass %.
(3) The aromatic polyene monomer is one or more selected from polyenes having 5 to 20 carbon atoms and having a plurality of vinyl groups and/or vinylene groups in the molecule, and the content of the vinyl groups and/or vinylene groups derived from the aromatic polyene monomer units is 2 to 30 per number average molecular weight.
(4) One or more olefin monomer units having 2 to 20 carbon atoms may be contained, and when the aromatic vinyl compound monomer unit and the aromatic polyene monomer unit are present, the total amount of the olefin monomer units is 100 mass%. A cured product obtained from the composition described in claim 1. The hardened body according to claim 6, which is an electrical insulating material. A CCL substrate, an FCCL substrate, an interlayer insulating material, or a coverlay, comprising the cured product according to claim 6. A CCL substrate, an FCCL substrate, an interlayer insulating material, or a coverlay, comprising the cured product according to claim 7.