Resin composition, and composite material set

Abstract

A resin composition according to the present invention contains an olefin-aromatic vinyl compound-aromatic polyene copolymer and a surface-treated silica powder. The surface-treated silica powder satisfies a (D90-D10) / D50 of 0.8-4.5, where D10 is the particle size at which the cumulative value from the small particle size side is 10%, D50 is the particle size at which the cumulative value is 50%, and D90 is the particle size at which the cumulative value is 90%, in the volume frequency particle size distribution of the powder as measured by a laser diffraction scattering method, and the moisture content generated from above 550°C and up to 900°C as measured by the Karl Fischer method is 500 ppm or less.

Description

Resin composition and composite material set

[0001] The present invention relates to a resin composition and a composite material set.

[0002] Various developments have been made so far regarding resin compositions containing olefin-polyene copolymers. For example, the technology described in Patent Document 1 is known as an example of this type of technology. Patent Document 1 describes a post-curable resin composition containing an ethylene-olefin-polyene copolymer and an inorganic filler (e.g., paragraph 0032 of Patent Document 1).

[0003] JP 2010-280771 A

[0004] However, as a result of investigations by the present inventors, it has been found that there is room for improvement in terms of low dielectric tangent and flowability of the resin composition containing an ethylene-olefin-polyene copolymer and an inorganic filler as described in Patent Document 1.

[0005] As a result of further investigations, the present inventors have found that, in a resin composition comprising an olefin-aromatic vinyl compound-aromatic polyene copolymer and a surface-treated silica powder, the fluidity of the resin composition can be stably evaluated by using the moisture content of the surface-treated silica powder as an index, and by using the dielectric loss tangent of the resin composition and the width of the particle size distribution of the surface-treated silica powder as indexes; and that the dielectric loss tangent can be lowered by setting the upper limit of the moisture content to a predetermined value or less, and that the fluidity can be increased by setting the lower limit of the width of the particle size distribution to a predetermined value or more, thereby completing the present invention.

[0006] According to one aspect of the present invention, the following resin composition and composite material set are provided: 1. A resin composition comprising an olefin-aromatic vinyl compound-aromatic polyene copolymer and a surface-treated silica powder, wherein in a volume frequency particle size distribution of the powder measured by a laser diffraction scattering method, where D10 is the particle size at which a cumulative value from the small particle size side reaches 10%, D50 is the particle size at which the cumulative value reaches 50%, and D90 is the particle size at which the cumulative value reaches 90%, the ratio (D90-D10) / D50 satisfies 0.8 to 4.5, and the amount of carbon generated at a temperature exceeding 550°C and reaching 900°C, as measured by the Karl Fischer method, is 500 ppm or less. 2. The resin composition according to 1., wherein the specific surface area of ​​the surface-treated silica powder measured by a BET single-point method using nitrogen gas adsorption is 0.1 m ２ / g or more 12.0m ２ / g or less. 3. The resin composition according to 1. or 2., wherein, when D50 is the particle diameter at which the cumulative value from the small particle diameter side reaches 50% in the volume frequency particle size distribution of the surface-treated silica powder measured by a laser diffraction scattering method, the D50 of the surface-treated silica powder is 0.1 μm or more and 10 μm or less. 4. The resin composition according to any one of 1. to 3., wherein the number average molecular weight Mn of the olefin-aromatic vinyl compound-aromatic polyene copolymer is 500 or more and 100,000 or less. 5. The resin composition according to any one of 1. to 4., wherein the water absorption rate of the olefin-aromatic vinyl compound-aromatic polyene copolymer is 1.0% or less. 6. a composite material set including a combination of raw material components used to produce a resin composition containing an olefin-aromatic vinyl compound-aromatic polyene copolymer and silica powder, the composite material set including: a resin varnish containing an olefin-aromatic vinyl compound-aromatic polyene copolymer and a solvent; and a surface-treated silica powder, wherein the surface-treated silica powder has a ratio (D90-D10) / D50 of 0.8 or more and 4.5 or less, where D10 is the particle diameter at which a cumulative value from the small particle diameter side reaches 10%, D50 is the particle diameter at which a cumulative value reaches 50%, and D90 is the particle diameter at which a cumulative value reaches 90%, in a volume frequency particle size distribution of the powder measured by a laser diffraction scattering method; and the amount of moisture generated during the temperature range from over 550°C to 900°C, as measured by the Karl Fischer method, is 500 ppm or less.

[0007] According to the present invention, there are provided a resin composition and a composite material set which have a low dielectric loss tangent and excellent flowability in the resin composition.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by similar reference numerals, and descriptions thereof will be omitted where appropriate. Furthermore, the drawings are schematic diagrams and do not correspond to actual dimensional proportions.

[0009] The resin composition of this embodiment will be outlined below.

[0010] The resin composition of this embodiment includes an olefin-aromatic vinyl compound-aromatic polyene copolymer and a surface-treated silica powder. The surface-treated silica powder is configured such that, in a volume frequency particle size distribution of the powder measured by a laser diffraction scattering method, D10 is the particle diameter at which a cumulative value from the small particle diameter side reaches 10%, D50 is the particle diameter at which the cumulative value reaches 50%, and D90 is the particle diameter at which the cumulative value reaches 90%, such that (D90-D10) / D50 satisfies a ratio of 0.8 to 4.5, and the amount of moisture generated between 550°C and 900°C measured by the Karl Fischer method satisfies a ratio of 500 ppm or less.

[0011] Furthermore, in this embodiment, a composite material set including a combination of raw material components used to produce a resin composition containing an olefin-aromatic vinyl compound-aromatic polyene copolymer and silica powder can be provided. Such a composite material set includes a resin varnish containing an olefin-aromatic vinyl compound-aromatic polyene copolymer and a solvent, and the surface-treated silica powder.

[0012] Each component of the resin composition of this embodiment will be described in detail below.

[0013] <Olefin-Aromatic Vinyl Compound-Aromatic Polyene Copolymer> The olefin-aromatic vinyl compound-aromatic polyene copolymer (hereinafter sometimes simply abbreviated as "copolymer") is a copolymer comprising a structural unit A derived from an olefin monomer, a structural unit B derived from an aromatic vinyl compound monomer, and a structural unit C derived from an aromatic polyene monomer, and preferably satisfies all of the following conditions (1) to (4):

[0014] (1) The number-average molecular weight of the copolymer is 500 or more and 100,000 or less. (2) The aromatic vinyl compound monomer is an aromatic vinyl compound having 8 to 20 carbon atoms, and the content of aromatic vinyl compound monomer units in the copolymer is 0 to 70 mass%. (3) The aromatic polyene 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 aromatic polyene units in the copolymer is 1.5 to less than 20 per number-average molecular weight. (4) The olefin is one or more selected from olefins having 2 to 20 carbon atoms, and the total of the olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units in the copolymer is 100 mass%.

[0015] The structural unit A can enhance the low dielectric properties and flexibility of the copolymer. The structural unit B can enhance the low dielectric properties and compatibility with other materials of the copolymer. The structural unit C can enhance the low dielectric properties and crosslinkability of the copolymer. That is, a hydrocarbon-based copolymer comprising the structural units A, B, and C can be a crosslinkable low dielectric resin, preferably a soft low dielectric resin having crosslinkability. Generally, the use of a soft resin such as polybutadiene can enhance crosslinkability, but the dielectric loss tangent tends to decrease. In contrast, in this embodiment, by comprising the structural units A, B, and C, it is possible to realize a copolymer that is a crosslinkable soft resin but has low dielectric properties. A resin composition containing such a copolymer can realize a high-frequency resin material with reduced signal transmission loss in the high-frequency range. Furthermore, the properties derived from the structural units of the copolymer provide the following advantages. The compatibility of the copolymer enhances solubility in solvents, allowing the resin composition to be used in the form of a resin varnish with excellent processability. The compatibility of the copolymer increases its compatibility with other resins, such as hard resins, making it possible to create resin compositions containing other resins as composite materials.The crosslinkability of the copolymer allows for the creation of high-frequency resin materials with relatively high heat resistance.

[0016] The olefin monomer does not include unsaturated hydrocarbons having aromatic groups, but is, for example, one or more selected from α-olefins having from 2 to 20 carbon atoms and cyclic olefins having from 5 to 20 carbon atoms, and is a compound composed of carbon and hydrogen without substantially containing oxygen, nitrogen, or halogens. Examples of α-olefins having from 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decane, 1-dodecane, 4-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene. Examples of cyclic olefins having from 5 to 20 carbon atoms include norbornene and cyclopentene. Preferred olefins are a combination of ethylene and an α-olefin other than ethylene or a cyclic olefin, or ethylene alone. Ethylene alone, or a mass ratio of the contained α-olefin other than ethylene to ethylene of 1 / 7 or less, more preferably 1 / 10 or less, is preferred, as it can increase the peel strength of the resulting cured product with copper foil or copper wiring. More preferably, the content of α-olefin monomer units other than ethylene in the copolymer is 6% by mass or less, most preferably 4% by mass or less, or the olefin is ethylene alone. In this case, the peel strength with copper foil or copper wiring can be further increased, which is more preferable. Furthermore, with the preferred combination of ethylene and an α-olefin other than ethylene, the glass transition temperature of the ethylene-α-olefin-aromatic vinyl compound-aromatic polyene sequence of the finally obtained cured product can be freely adjusted within the range of approximately -60°C to -10°C depending on the type and content of the α-olefin.

[0017] The aromatic vinyl compound monomer is an aromatic vinyl compound having 8 to 20 carbon atoms, and examples thereof include styrene, paramethylstyrene, paraisobutylstyrene, various vinylnaphthalenes, and various vinylanthracenes.

[0018] The aromatic polyene monomer is a polyene having 5 to 20 carbon atoms and containing multiple vinyl groups and / or vinylene groups (preferably vinyl 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 divinylbenzenes are used as aromatic polyenes, they are preferred because they have high curing efficiency and are easy to cure when subjected to a curing treatment.

[0019] Each of the olefin, aromatic vinyl compound, and aromatic polyene monomers may independently contain a polar group, such as an olefin containing an oxygen atom, a nitrogen atom, or the like, an aromatic vinyl compound containing an oxygen atom or a nitrogen atom, or an aromatic polyene containing an oxygen atom or a nitrogen atom, etc. The total mass of these polar group-containing monomers in each monomer is preferably 10 mass% or less, more preferably 3 mass% or less, of the total mass of the composition, and most preferably no polar group-containing monomer is included. By keeping the amount of such monomers at 10 mass% or less, the low dielectric properties (low dielectric constant / low dielectric loss) of the cured body obtained by curing the composition can be improved.

[0020] The number-average molecular weight of the copolymer is 500 to 100,000, preferably 5,000 to 100,000, more preferably 20,000 to 100,000, and even more preferably 30,000 to 100,000. By adjusting the number-average molecular weight within the above range, the copolymer becomes less sticky in the uncured state even when other resins described below are added, improving thermoplasticity. Furthermore, the final cured product can be easily endowed with good physical properties such as high strength at break and high elongation at break. If the number-average molecular weight is less than 500, the composition in the uncured state has poor mechanical properties and high tack, making it difficult to mold the composition as a thermoplastic resin. If the number-average molecular weight is higher than 100,000, molding processability may be reduced.

[0021] In this specification, the number average molecular weight is determined as follows. The molecular weight is determined as the number average molecular weight (Mn) converted to standard polystyrene using GPC (gel permeation chromatography). Measurements can be performed under the following conditions. Column: Four TSKgel GMHXL φ7.8×300 mm columns (manufactured by Tosoh Corporation) connected in series are used. Column temperature: 40° C. Solvent: THF Flow rate: 1.0 ml / min. Detector: RI detector

[0022] The content of aromatic vinyl compound monomer units contained in the copolymer is 0% by mass or more and 70% by mass or less, preferably 0% by mass or more and less than 70% by mass, more preferably 10% by mass or more and 60% by mass or less, and even more preferably 10% by mass or more and 55% by mass or less. If the content of aromatic vinyl compound monomer units is more than 70% by mass, the glass transition temperature of the cured product of the final composition will be near room temperature, which may result in reduced toughness and elongation at low temperatures. If the content of aromatic vinyl compound monomer units is 10% by mass or more, the aromaticity of the copolymer is improved, improving compatibility with flame retardants and fillers, preventing bleed-out of the flame retardant and allowing the filler to be filled. Furthermore, if the content of aromatic vinyl compound monomer units is 10% by mass or more, a cured product of the composition having high peel strength with copper foil or copper wiring can be obtained.

[0023] In the copolymer, the content of vinyl groups and / or vinylene groups derived from aromatic polyene units is 1.5 or more and less than 20, preferably 1.5 or more and less than 7, and more preferably 2 or more and less than 5 per number average molecular weight. The content of vinyl groups and / or vinylene groups is hereinafter sometimes collectively referred to as the "vinyl group content." If the vinyl group content is less than 1.5, the crosslinking efficiency is low, making it difficult to obtain a cured product with sufficient crosslink density. Increasing the vinyl group content makes it easier to improve the mechanical properties of the final cured product at room temperature and high temperatures.

[0024] The vinyl group content derived from aromatic polyene units (divinylbenzene 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 It can be obtained by comparing the vinyl group content and vinylene group content derived from aromatic polyene units obtained by H-NMR measurement. For example, １ By comparing the intensities of each peak area obtained by H-NMR measurement, if the content of vinyl groups derived from aromatic polyene units (divinylbenzene units) in the copolymer is 0.095% by mass, and the number average molecular weight in terms of standard polystyrene measured by GPC is 68,000, the molecular weight of vinyl groups derived from aromatic polyene units in the number average molecular weight is the product of these, 64.8, which is divided by the formula weight of the vinyl groups, 27, to obtain 2.4. In other words, the content of vinyl groups derived from aromatic polyene units per number average molecular weight in this copolymer is 2.4. １ The assignment of peaks obtained by H-NMR measurement is known from literature. １ A method for determining the composition of a copolymer by comparing peak areas obtained by H-NMR measurement is also known. １３ The peak area or ratio of the peak area in the C-NMR spectrum may be used. In this specification, the content of the divinylbenzene unit in the copolymer is determined based on the peak intensity ( １In other words, the content of divinylbenzene units is calculated from the content of vinyl groups derived from divinylbenzene units, assuming that one vinyl group is derived from one divinylbenzene unit in the copolymer.

[0025] In the copolymer, the olefin monomer unit content is preferably 30% by mass or more, and particularly preferably 45% by mass or more. The total of the olefin monomer units, aromatic vinyl compound monomer units, and aromatic polyene monomer units is 100% by mass. When the olefin monomer unit content is 30% by mass or more, the toughness (elongation) of the final cured body is improved, and cracking during curing, a decrease in the impact resistance of the cured body, and cracking during heat cycle testing of the cured body do not occur. In this copolymer, the olefin monomer unit content is preferably 90% by mass or less.

[0026] In the copolymer, specific examples of suitable olefin-aromatic polyene copolymers that do not contain aromatic vinyl compound monomer units include ethylene-divinylbenzene copolymer, ethylene-propylene-divinylbenzene copolymer, ethylene-1-butene-divinylbenzene copolymer, ethylene-1-hexene-divinylbenzene copolymer, and ethylene-1-octene-divinylbenzene copolymer.

[0027] In the copolymer, examples of the olefin-aromatic vinyl compound-aromatic polyene copolymer containing an aromatic vinyl compound monomer unit include an ethylene-styrene-divinylbenzene copolymer, an ethylene-propylene-styrene-divinylbenzene copolymer, an ethylene-1-hexene-styrene-divinylbenzene copolymer, and an ethylene-1-octene-styrene-divinylbenzene copolymer.

[0028] The upper limit of the water absorption of the copolymer is, for example, 1.0% or less, preferably 0.5% or less, and more preferably 0.1% or less. The lower limit of the water absorption of the copolymer is not particularly limited, but may be equal to or greater than the measurement limit. The water absorption of the copolymer is determined by immersing the copolymer in water at 25°C in the atmosphere for 24 hours and measuring the change in weight before and after immersion in water.

[0029] The copolymer can be produced by the production methods described in, for example, WO 00 / 37517, JP 2009-161743 A, JP 2010-280771 A, JP 2009-161743 A, JP 2010-280771 A, etc.

[0030] <Surface-treated silica powder>

[0031] In the surface-treated silica powder, the upper limit of the amount of moisture generated from above 550°C to 900°C, as measured by the Karl Fischer method, is 500 ppm or less, preferably 400 ppm or less, and more preferably 300 ppm or less. This allows the dielectric loss tangent of the resin composition to be reduced. On the other hand, the lower limit of the amount of moisture generated from above 550°C to 900°C is not particularly limited, but may be 0 ppm or more or 1 ppm or more.

[0032] The moisture content in a powder can be measured by the Karl Fischer method as follows: Specifically, a trace moisture analyzer (Model CA-05, manufactured by Mitsubishi Chemical Corporation) is used, the powder is placed in a quartz tube in a moisture vaporization mechanism, and while heating from room temperature to 900°C with an electric heater, dehydrated argon gas is supplied as a carrier gas, and the water vapor volatilized from the powder surface is introduced into the moisture measurement mechanism to measure the moisture content.

[0033] In the volume frequency particle size distribution of the surface-treated silica powder measured by the laser diffraction scattering method, the particle size at which the cumulative value from the small particle size side reaches 10% is defined as D10, the particle size at which the cumulative value reaches 50%, and the particle size at which the cumulative value reaches 90% is defined as D90.

[0034] The lower limit of (D90-D10) / D50 is 0.8 or more, preferably 0.9 or more, and more preferably 1.0 or more. This can improve the fluidity of the resin composition. The upper limit of (D90-D10) / D50 is, for example, 4.5 or less, preferably 4.0 or less, and more preferably 3.5 or less. This can further reduce the dielectric loss tangent of the resin composition.

[0035] The lower limit of D50 is, for example, 0.1 μm or more, preferably 0.2 μm or more, and more preferably 0.3 μm or more. This can improve the filling property into the resin. The upper limit of D50 is, for example, 10 μm or less, preferably 9 μm or less, and more preferably 8 μm or less. This can reduce the amount of coarse particles, and can make the sheet thickness thinner when the resin composition is molded into a sheet.

[0036] The lower limit of the specific surface area (S) of the surface-treated silica powder measured by the BET single-point method using nitrogen gas adsorption is, for example, 0.1 m ２ / g or more, preferably 0.3m ２ / g or more, more preferably 0.5m ２ This allows the amount of silica powder added to the resin to be increased, and the thermal expansion coefficient of the resin composition to be suppressed. The upper limit of the specific surface area (S) of the surface-treated silica powder is, for example, 12.0 m ２ / g or less, preferably 8.5m ２ / g or less, more preferably 7.0m ２ / g or less, which can suppress the aggregation of the filler.

[0037] The BET single-point method using nitrogen gas adsorption can be performed using a specific surface area measuring device (for example, manufactured by Yuasa Ionics Co., Ltd., device name: MONOSORB) using nitrogen gas as the adsorption gas and helium gas as the carrier gas, after drying and degassing 1 g of sample at 300°C for 15 minutes.

[0038] The lower limit of the average sphericity of the surface-treated silica powder is, for example, 0.80 or more, preferably 0.85 or more, and more preferably 0.90 or more. This can further improve the fluidity of the resin composition. The upper limit of the average sphericity of the surface-treated silica powder is not particularly limited, but may be, for example, 1.00 or less.

[0039] In this embodiment, the moisture content can be controlled by appropriately selecting, for example, the method for preparing the raw silica powder or the method for surface-treating the raw silica powder. Among these, factors for achieving the desired moisture content range include appropriately adjusting the specific surface area of ​​the raw silica powder, adjusting the amount of silane coupling agent added per specific surface area depending on the type of silane coupling agent, and performing a heat treatment before the silane coupling treatment. Furthermore, the particle size distribution of the surface-treated silica powder, such as (D90-D10) / D50, can be controlled by classification using a classifier such as a sieve or a precision air classifier.

[0040] The surface-treated silica powder is silica (SiO ２ The main component is silica (SiO) in terms of mass in the total amount of silica powder. ２ ) for example, 50% or more, preferably 80% or more, more preferably 90% or more.

[0041] The surface-treated silica powder includes either or both of amorphous and crystalline silica.

[0042] The surface-treated silica powder preferably has an amorphous ratio of 95% or more, and more preferably 97% or more, as measured by the method described below. The amorphous ratio is measured by performing X-ray diffraction analysis using a powder X-ray diffractometer (e.g., a "Model MiniFlex" manufactured by RIGAKU Corporation) with CuKα radiation at 2θ in the range of 26° to 27.5°, and then determining the ratio from the intensity ratio of specific diffraction peaks. In the case of siliceous powder, crystalline silica exhibits a main peak at 26.7°, while amorphous silica exhibits no peak. When amorphous silica and crystalline silica are mixed, a peak height at 26.7° corresponding to the proportion of crystalline silica is obtained. Therefore, the crystalline silica mixing ratio (X-ray diffraction intensity of sample / X-ray diffraction intensity of crystalline silica) is calculated from the ratio of the X-ray intensity of the sample to the X-ray intensity of a crystalline silica standard sample, and the amorphous ratio is then calculated using the formula: amorphous ratio (%) = (1 - crystalline silica mixing ratio) x 100.

[0043] The silane coupling agent may contain a silane compound having one or more functional groups selected from the group consisting of, for example, an epoxy group, a methacryl group, an acrylic group, an amino group, a vinyl group, an alkyl group, a phenyl group, a mercapto group, a styryl group, an acid anhydride group, a ureido group, an isocyanurate group, and an isocyanate group, preferably an epoxy group, a methacryl group, an acrylic group, an amino group, a vinyl group, an alkyl group, and a phenyl group.

[0044] The silane compound has one or more hydrolyzable groups in addition to functional groups in its molecule. Examples of the hydrolyzable groups include alkoxy groups such as methoxy and ethoxy groups. The alkoxy groups generate silanol groups upon hydrolysis. These silanol groups chemically react with OH groups (reactive sites) present on the surface of the silica particles, thereby chemically bonding the silane coupling agent to the surface of the silica particles. The surface-treated silica powder has the silane coupling agent chemically and / or physically bonded to the surface of the silica particles.

[0045] Examples of silane compounds having an epoxy group include 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, etc. Examples of silane compounds having a methacryl group include 3-methacryloxypropyltrimethoxysilane, 8-methacryloxyoctyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. Examples of silane compounds having an acrylic group include 3-acryloxypropyltrimethoxysilane, etc. Examples of silane compounds having an amino group include N-phenyl-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride. Examples of silane compounds having a vinyl group include vinyltrimethoxysilane, 7-octenyltrimethoxysilane, and vinyltriethoxysilane. Examples of silane compounds having an alkyl group include hexyltrimethoxysilane, octyltriethoxysilane, and decyltrimethoxysilane. Examples of silane compounds having a phenyl group include phenyltrimethoxysilane and trimethoxy(2-phenylethyl)silane.

[0046] The content of the surface-treated silica powder is, for example, 1 to 90 mass%, preferably 10 to 80 mass%, more preferably 20 to 70 mass%, relative to 100 mass% of the total content of the surface-treated silica powder and the copolymer.

[0047] Next, a method for producing the surface-treated silica powder will be described.

[0048] An example of a method for producing a surface-treated silica powder includes the steps of: heat-treating a prepared silica powder; and bringing a silane coupling agent into contact with the heat-treated silica powder to carry out a silane coupling treatment in which the silane coupling agent reacts with the surfaces of the silica particles, thereby obtaining a surface-treated silica powder. According to this embodiment, the two-stage surface treatment of heat treatment and silane coupling treatment can realize a surface-treated silica powder with excellent low dielectric properties.

[0049] In this embodiment, the silica powder can be prepared by, for example, subjecting raw silica powder produced by a dry method to coarse powder classification followed by fine powder classification. The classification can be performed by mixing or classifying appropriate amounts of silica powders with different particle size compositions. Industrially, classification using a classifier such as a sieve or precision air classifier is desirable, and a dry method is preferred for the classification operation. Dry classification of raw silica powder produced by a dry method can suppress aggregation of the silica powder and improve handling, compared to raw silica powder produced by a wet method and / or wet classification. The obtained silica powder is preferably stored in a moisture-proof bag.

[0050] The raw silica powder can be produced by any method, such as by introducing crushed powder of silica stone, silica sand, quartz, etc. into a flame or high-temperature plasma and spheroidizing it; by synthesizing and spheroidizing it by gas-phase hydrolysis of silicon tetrachloride and using this as a raw material and subjecting it to calcination or flame spraying treatment; or by synthesizing and spheroidizing it in the gas or liquid phase using metallic silicon or alkoxysilane as a starting material and subjecting it to further calcination or flame spraying treatment and spheroidizing it.

[0051] The prepared silica powder is subjected to a heat treatment under the following conditions. The heat treatment is carried out at a temperature of 500 to 1100°C for a predetermined time (e.g., about 1 to 52 hours) such that the heating temperature (°C) x heating time (h) is 1000 to 26400 (°C·h), preferably 1800 to 17600 (°C·h) (e.g., about 2 to 35 hours) in a hot air or electric furnace. Since the specific surface area and average particle size do not change before and after heating when the heating temperature is 500 to 1100°C, it is desirable to perform the classification step before heating, adjust the specific surface area and average particle size to the desired value, and then perform the heat treatment. After the heat treatment, the silica powder is allowed to cool naturally in the electric furnace and then recovered at 110 to 300°C. It is then further cooled to 25°C in an environment with a humidity of 40% RH or less, and stored at 15 to 25°C. It may also be recovered and stored in a moisture-proof aluminum bag.

[0052] The heat-treated silica powder is subjected to a silane coupling treatment using a silane coupling agent. Well-known techniques such as dry and wet methods can be used for the surface treatment using a silane coupling agent, but it is preferable to use the dry method. The dry method is not particularly limited as long as it is a method of contacting a silane coupling agent with a solid spherical silica powder, and well-known methods can be used, such as a stirring method with shear force, a mixing method using a ball mill, a mixer, etc. Here, the solid state refers to a state in which the raw silica powder is not dispersed in a dispersion medium. Incidentally, an acidic or alkaline substance may be present during the treatment with the silane coupling agent.

[0053] The silane coupling agent treatment is carried out, for example, by adding a silane coupling agent to the heat-treated silica powder and mixing them for 10 minutes to 10 hours using the above-mentioned mixing method under atmospheric pressure, a temperature of 0 to 120°C, and a humidity of 10 to 90%. If necessary, the mixture may be allowed to stand for 0 to 10 days under the same environmental conditions after mixing. Thereafter, if necessary, the coupling agent-treated silica powder may be further dried at 100 to 300°C for 1 to 10 hours.

[0054] <Resins Other Than the Copolymer> The resin composition of this embodiment may contain other resins other than the copolymer described above, as needed, as long as the effects of the present invention are not impaired. The other resins may preferably be one or more selected from hydrocarbon-based elastomers, polyphenylene ethers, and aromatic polyene-based resins. Among these, polyphenylene ethers or hydrocarbon-based elastomers are more preferred. Among hydrocarbon-based elastomers, conjugated diene-based polymers are preferred. Among conjugated diene-based polymers, 1,2-polybutadiene is preferred. By using one or more selected from hydrocarbon-based elastomers, polyphenylene ethers, and aromatic polyene-based resins, the amount of monomer used can be reduced, and for example, a suitable cured product of the present invention can be obtained without using a monomer. The amount of the other resins may be preferably 1 to 500 parts by weight, more preferably 1 to 300 parts by weight, per 100 parts by weight of the copolymer.

[0055] <Curing Agent> The resin composition of this embodiment may contain a curing agent for the copolymer and / or other resins, as needed, as long as the effects of the present invention are not impaired. Known curing agents that have been used for the polymerization or curing of aromatic polyenes and aromatic vinyl compounds may be used as the curing agent. Examples of such curing agents include radical polymerization initiators, cationic polymerization initiators, and anionic polymerization initiators, with radical polymerization initiators being preferred. Organic peroxides and azo-based polymerization initiators are preferred, and can be selected freely depending on the application and conditions. Known photopolymerization initiators that utilize light, ultraviolet light, or radiation can also be used as the curing agent. Examples of curing agents that utilize a photopolymerization initiator include photoradical polymerization initiators, photocationic polymerization initiators, and photoanionic polymerization initiators. Such photopolymerization initiators are available, for example, from Tokyo Chemical Industry Co., Ltd. Furthermore, curing using radiation or electron beams themselves is also possible. Crosslinking and curing by thermal polymerization of the raw materials contained therein without the use of a curing agent is also possible. There are no particular restrictions on the amount of curing agent used, but generally, 0.01 to 10 parts by mass per 100 parts by mass of the composition (preferably excluding the curing agent and solvent) is preferred. When using a curing agent such as a peroxide or azo-based polymerization initiator, the curing treatment is carried out at an appropriate temperature and time, taking into account its half-life. In this case, the conditions are optional depending on the curing agent, but generally, a temperature range of approximately 50°C to 180°C is appropriate.

[0056] <Monomer> The resin composition of this embodiment may contain a monomer as needed, as long as it does not impair the effects of the present invention. The amount of the monomer is optional, but is preferably 300 parts by mass or less per 100 parts by mass of the copolymer. The composition may be substantially free of a monomer. If a monomer is contained, the amount is preferably 1 part by mass or more, more preferably 5 parts by mass or more. When the monomer amount is 300 parts by mass or less, the uncured composition does not become viscous, making it easy to mold and process as a thermoplastic resin. Furthermore, when the content of volatile monomers is below a certain level, odor in the uncured state is not a problem. When a solvent is added to the composition to produce a varnish-like product, the monomer is lost as the solvent evaporates during use, which can lead to a problem of a decrease in the actual content of the monomer. Furthermore, when the product is in the form of an uncured sheet, containing a certain amount of monomer or less reduces the change in the monomer content during storage. Monomers suitable for use 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 aromatic vinyl compound monomers, aromatic polyene monomers, and / or polar monomers. The monomers are preferably monomers that can be polymerized with a radical polymerization initiator, and more preferably one or more monomers from the group consisting of aromatic vinyl compounds and aromatic polyenes. Also suitable for use is BVPE (1,2-bis(vinylphenyl)ethane), as described in JP-A-2003-212941.

[0057] The amounts of the monomers used can be exemplified as follows. From the viewpoint of increasing the mechanical strength (elastic modulus) of the cured product at high temperatures, the amount of the aromatic vinyl compound is preferably 50 parts by mass or more and 250 parts by mass or less, and more preferably 80 parts by mass or more and 200 parts by mass or less, per 100 parts by mass of the copolymer. From the viewpoint of increasing the mechanical strength (elastic modulus) of the cured product at high temperatures, the amount of the aromatic polyene is preferably 1 part by mass or more and 30 parts by mass or less, per 100 parts by mass of the copolymer. When an aromatic vinyl compound and an aromatic polyene are used, the mass ratio of the aromatic vinyl compound to the aromatic polyene is preferably 70-99:1-30, more preferably 85-95:5-15, per 100 parts by mass of the total of the aromatic vinyl compound and the aromatic polyene.

[0058] Preferably, a relatively small amount of polar monomer can be used for the purpose of imparting adhesion to other materials required as an insulating material or imparting or adjusting the mechanical properties of the cured product. Examples of the polar monomer include various maleimides, bismaleimides, maleic anhydride, glycidyl (meth)acrylate, triallyl isocyanurate, tri(meth)acrylic isocyanurate, and trimethylolpropane tri(meth)acrylate. Maleimides and bismaleimides that can be used in the present invention are described, for example, in International Publication No. 2016 / 114287 and Japanese Patent Application Laid-Open No. 2008-291227, and can be purchased, for example, from Daiwa Chemical Industry Co., Ltd. or Designer Molecules Inc. These maleimide group-containing compounds may be used as polyaminobismaleimide compounds from the viewpoints of solubility in organic solvents, high-frequency characteristics, high adhesion to conductors, and prepreg moldability. Polyaminobismaleimide compounds can be obtained, for example, by subjecting a compound having two maleimide groups at its terminals to a Michael addition reaction with an aromatic diamine compound having two primary amino groups in the molecule. To achieve high crosslinking efficiency with a small amount of addition, polar monomers having bifunctional or higher polyfunctional groups are preferred, such as bismaleimides, triallyl isocyanurate (TAIC), and trimethylolpropane tri(meth)acrylate. The amount of polar monomer that may be included in the composition may be in the range of 0.1 to 30 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the copolymer. Using 30 parts by weight or less results in low dielectric constants and dielectric loss tangents for the resulting cured product.

[0059] <Solvent> The resin composition of this embodiment may contain a solvent, if necessary. The solvent is used to adjust the viscosity and fluidity of the composition. Volatile solvents are preferred, such as cyclohexane, toluene, ethylbenzene, acetone, and isopropanol. The amount of solvent used is preferably 10 parts by mass or less per 100 parts by mass of the copolymer of the present invention. From the viewpoint of moldability and handling of the composition as a thermoplastic resin before curing, and from the viewpoint of removal during and after curing, it is more preferable to use substantially no solvent. "Substantially no solvent" preferably means 5 parts by mass or less, more preferably 1 part by mass or less, and most preferably 0 parts by mass. Particularly when used as a varnish, it is preferable to add an appropriate solvent to the composition of the present invention. The solvent is used to adjust the viscosity and fluidity of the composition as a varnish. A solvent with a high boiling point at atmospheric pressure, i.e., low volatility, results in a uniform thickness of the applied film; therefore, a solvent with a boiling point above a certain level is preferred. A preferred boiling point is 100°C or higher at atmospheric pressure, more preferably 110°C or higher and 300°C or lower. Suitable solvents for such varnishes include cyclohexane, toluene, xylene, mesitylene, tetralin, acetone, ethylbenzene, limonene, mixed alkanes, mixed aromatic solvents, ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether, etc. The amount used is preferably in the range of 10 to 2,000 parts by mass, more preferably 5 to 500 parts by mass, and even more preferably 10 to 300 parts by mass, per 100 parts by mass of the composition of the present invention.

[0060] <Other Additives> The resin composition of the present embodiment may contain additives other than the above-described components as necessary, as long as the effects of the present invention are not impaired. Examples of other additives include fillers other than the surface-treated silica powder, antioxidants, weathering agents, light stabilizers, lubricants, compatibilizers, antistatic agents, flame retardants, surface modifiers, heat stabilizers, UV absorbers, antiaging agents, lubricants, colorants, and pigments. These may be contained alone or in any combination of two or more.

[0061] Examples of other fillers include known inorganic or organic fillers other than the surface-treated silica powder. When adding an inorganic filler, it is particularly preferable to use a known surface modifier, such as a silane coupling agent. The type and amount of other fillers can be appropriately selected depending on the purpose. From the viewpoint of low dielectric loss tangent, examples of inorganic fillers include boron nitride (BN). Examples of organic fillers include high-molecular-weight polyethylene and ultra-high-molecular-weight polyethylene.

[0062] The resin composition of the present embodiment can be in the form of a product such as a "thermoplastic composition," a "semi-cured state (such as a B-stage sheet)," or a "varnish" by appropriately adjusting the blending ratio of the copolymer, the surface-treated silica powder, and these, and, if necessary, the blending ratio of other resins, monomers, solvents, other additives, and the like.

[0063] <Thermoplastic Composition, Molded Article> The resin composition of this embodiment uses a copolymer having a molecular weight above a certain range and further contains the specified other resins, thereby exhibiting the properties of a thermoplastic resin. Therefore, under conditions that do not cause crosslinking, it can be molded into shapes such as sheets, tubes, strips, and pellets in a substantially uncured state using known molding and processing methods for thermoplastic resins. The molded article may then be crosslinked (cured). A preferred embodiment of this composition is as follows. When the other resin, excluding resins that are liquid at room temperature, contains a certain proportion or more of one or more resins selected from the hydrocarbon-based elastomer, polyphenylene ether, olefin-aromatic vinyl compound-aromatic polyene copolymer oligomer, or aromatic polyene-based resin, the composition can be easily molded as a thermoplastic resin in an uncured state. Specifically, the hydrocarbon-based elastomer (excluding liquid resins) and / or polyphenylene ether can be added in an amount of 30 to 200 parts by mass per 100 parts by mass of the copolymer. Furthermore, when the other resin is liquid at room temperature, it can be added in an amount of preferably 1 to 30 parts by weight, particularly preferably 1 to 20 parts by weight, per 100 parts by weight of the copolymer. The amount of monomer used in the thermoplastic composition may be preferably 10 parts by weight or less per 100 parts by weight of the copolymer. The number-average molecular weight of the copolymer used is 500 to 100,000, preferably 20,000 to 100,000, and more preferably 30,000 to 100,000. The thermoplastic composition described above may be molded into various shapes, such as a sheet, at or below the active temperature of the curing agent to utilize its thermoplasticity. If necessary, the composition may be combined with a semiconductor element, wiring, or a substrate and laminate, followed by heat curing and bonding. In a preferred embodiment, forming the thermoplastic composition of the present invention containing surface-treated silica into a molded product (either an uncured or semi-cured molded product) in advance has the advantage of easily suppressing increases in the dielectric constant and dielectric loss tangent associated with water absorption (water adsorption) of the silica. Sheet or pellet shapes are preferred for such molded products. Such a molded product is also useful as a masterbatch, and in particular, when it is in the form of pellets, it is suitable as a masterbatch when adding the surface-treated silica to other materials.The composition of the present invention may be provided as a sheet obtained by molding the composition, heated and melted at a temperature below the curing agent's working temperature or decomposition temperature, using a known method. Forming into a sheet may be achieved by T-die extrusion, two-roll extrusion, or extrusion lamination onto a substrate film. In this case, the composition's composition, copolymer / monomer mass ratio, or solvent, other resin, and flame retardant are selected and adjusted so that the composition melts at the curing agent's working temperature or below its decomposition temperature and becomes solid at around room temperature. In this case, the sheet is substantially uncured. After various processing and assembly steps, the sheet is finally treated at a temperature and time above the curing agent's working temperature or decomposition temperature to achieve complete curing. This method is a common technique used for ethylene-vinyl acetate resin-based crosslinked sealant sheets for solar cells (photovoltaic power generation devices).

[0064] <Molded Article in a Semi-Cured State (B-Stage Sheet, etc.)> The composition of the present invention can also be formed into a molded article, such as a sheet or tube, in a partially crosslinked state, for example, a state in which a portion of the curing agent contained therein has reacted to semi-cure (so-called B-stage state). For example, by employing multiple curing agents and / or curing conditions with different curing temperatures, the composition can be semi-cured and the melt viscosity and fluidity can be controlled to form a B-stage state. That is, the curable resin or composition can be molded into an easily handled B-stage sheet by a first curing step (partial curing), which can then be laminated and pressure-bonded to an electronic device or substrate, and then subjected to a second curing step (complete curing) to form the final shape. In this case, the composition composition, i.e., the copolymer / monomer mass ratio, can be selected, and if necessary, a solvent, other resins, and a flame retardant can be added. The composition can further contain a curing agent such as a peroxide and be partially cured to form a sheet (B-stage state). After molding and assembling the device, the composition can be fully cured by heating under pressure. Known methods can be used to partially cure the composition. For example, a method is available in which peroxides with different decomposition temperatures are used in combination, and treated for a predetermined time at a temperature at which only one of the peroxides is substantially active to obtain a semi-cured sheet, which is then finally treated for a sufficient time at a temperature at which all of the curing agents are active to achieve complete curing. Furthermore, the molded product may be a sheet. The sheet may be uncured (semi-cured) to the extent that it can maintain its sheet shape, or may be completely cured. The degree of curing of the composition can be quantitatively measured by known dynamic mechanical analysis (DMA).

[0065] <Varnish-like Composition and Molded Articles Thereof> The composition of the present invention can also be made into a viscous liquid varnish by adjusting its composition and blending ratio. For example, a sufficient amount of solvent and / or an appropriate amount of liquid monomer can be used to make the composition into a varnish. When used as a varnish, it is preferable to add an appropriate solvent to the composition of the present invention. The solvent is used to adjust the viscosity and fluidity of the composition as a varnish. A solvent with a high boiling point at atmospheric pressure, i.e., low volatility, contributes to a uniform thickness of the applied film, so a solvent with a boiling point above a certain level is preferred. A preferred boiling point is approximately 110°C or higher and 300°C or lower at atmospheric pressure. Examples of solvents suitable for such varnishes include toluene, xylene, mesitylene, ethylbenzene, limonene, ethylene glycol methyl ether acetate, ethylene glycol monoethyl ether acetate, and ethylene glycol monobutyl ether. The amount of the solvent used is preferably in the range of 10 to 2,000 parts by mass per 100 parts by mass of the composition of the present invention. The varnish can be applied to or impregnated into a substrate, and the solvent can be removed by drying or other methods to produce an uncured or semi-cured molded product. This molded product generally has the form of a sheet, film, or tape. The resulting uncured or semi-cured molded product can then be cured under specified conditions, such as by heating or pressing.

[0066] <Curing> The composition can be cured by a known method, taking into consideration the curing conditions (temperature, time, pressure) of the curing agent contained therein. When the curing agent used is a peroxide, the curing conditions can be determined by taking into consideration the half-life temperature and the like disclosed for each peroxide. <Cured product of the composition>

[0067] <General Uses of Composition> The composition of the present invention can be used as a base material / substrate such as a single-layer or multilayer printed circuit board, a flexible printed circuit board, a so-called single-layer or multilayer CCL (copper clad laminate), or a single-layer or multilayer FCCL (flexible copper clad laminate) substrate. It can also be used as various insulating materials for wiring, preferably for high-frequency signal wiring, such as coverlays, solder resists, build-up materials, interlayer insulating agents, bonding sheets, interlayer adhesives, and bump sheets for flip-chip bonders.

[0068] <Use of Composition as Uncured or Partially Cured Sheets> Uncured or partially cured sheets of the composition of the present invention can be suitably used as high-frequency electrical insulating materials. For example, they can be suitably used as build-up films, bonding sheets, coverlay sheets, bump sheets for flip-chip bonders, or insulating or adhesive layers for substrates. The composition of the present invention can be used as a replacement for conventionally used epoxy resin or silicone resin sheets. The composition of the present invention can form a cured insulating layer or cured matrix phase with a low dielectric constant and low dielectric loss by undergoing a curing treatment. The sheet generally has a thickness of 1 to 300 μm. The sheet may contain woven or nonwoven fabrics such as glass cloth or ceramic fibers. The sheet may be impregnated or may be multilayered with these. Furthermore, flexible, bendable wiring partially or completely insulated with the sheet can be used as an antenna cable for mobile phones and the like, replacing conventional coaxial cables. For example, wiring can be coated with the sheet of the present invention or a B-stage sheet (coverlay sheet) using an LCP (liquid crystal polymer), PPE sheet, fluorine-based resin, or polyimide resin as a substrate, cured, and bonded to the substrate to be used as an insulating material. Multilayer wiring boards in which the cured product obtained using the composition of the present invention forms an insulating layer can be wiring boards with low dielectric loss and excellent high-frequency characteristics. In this case, in addition to low dielectric loss, the advantages include heat resistance that can withstand soldering, and a certain degree of flexibility, elongation, and impact resistance that can withstand stress due to heat cycles or thermal expansion differences. For example, wiring boards can be produced by laminating and pressing a core material such as glass or quartz cloth, nonwoven fabric, film material, ceramic substrate, glass substrate, general-purpose resin plate such as epoxy, or general-purpose laminate with an insulating layer-attached conductor foil made of the cured product. Alternatively, an insulating layer can be formed by applying a slurry or solution containing the present composition to the core material, drying, and curing. The insulating layer generally has a thickness of 1 to 300 μm. Such multilayer wiring boards can also be used in a multilayered or integrated configuration.The cured product obtained by curing the varnish-like composition of the present invention can be suitably used as an electrical insulating material, as described above, particularly as a potting material, surface coating agent, coverlay, solder resist, buildup material, underfill material, insulating filler, interlayer insulating agent, or interlayer adhesive, or as a cured product for printed circuit boards, flexible printed circuit boards, CCL (copper clad laminate) substrates, FCCL (flexible copper clad laminate) substrates, or as a cured product for buildup films, bonding sheets, coverlay sheets, or bump sheets for flip chip bonders, and can be used as an electrical insulating material, particularly an electrical insulating material for high frequencies. In another aspect, the present invention relates to an olefin-aromatic vinyl compound-aromatic polyene copolymer, which comprises an olefin-aromatic vinyl compound-aromatic polyene copolymer having a storage modulus at 250°C of 10 MPa or more and 10 GPa or less, a dielectric constant at 23°C, 10 GHz, or 25 GHz to 40 GHz of 2.0 or more and 3.5 or less, and a dielectric dissipation factor of 1.2 x 10. －３The present invention can provide an electrical insulating material having the following properties. The uncured or semi-cured thermoplastic composition of the present invention can also be used to obtain a laminate by adhering it to a metal foil, particularly a copper foil for wiring, by heat and pressure treatment, without the need for any adhesive coating or adhesive treatment. Here, the concept of metal foil includes metal wiring. In particular, when the olefin-aromatic vinyl compound-aromatic polyene copolymer is used, preferably a copolymer having an aromatic vinyl compound content of 10% by mass or more, and / or when the olefin is ethylene alone or the mass ratio of olefin monomer components other than ethylene to the ethylene monomer component contained in the olefin is 1 / 7 or less, a peel strength of 1 N / mm or more can be obtained as measured in accordance with Japanese Industrial Standards (JIS) C6481:1996. Furthermore, a peel strength of 1.3 N / mm or more is more preferable. More preferably, the copolymer contains ethylene alone as the olefin, or the ratio of olefin monomer components other than ethylene to the ethylene monomer components contained in the olefin is 1 / 10 or less, and most preferably the copolymer contains 4 mass% or less of α-olefin monomer units other than ethylene, or the olefin is ethylene alone. The peel strength can be further improved. It is generally known that adhesive treatments deteriorate the dielectric properties of laminates such as copper-clad laminate sheets. Therefore, it is preferable to provide a peel strength of 1 N / mm or more, measured according to Japanese Industrial Standards (JIS) C6481:1996, even without such treatment. Thus, the uncured or semi-cured thermoplastic composition of the present invention can be bonded to metal foils, such as copper foils for wiring, by curing treatments such as heat and pressure treatments, without the need for adhesive coating or adhesive treatment. However, the present invention does not preclude the use of other adhesive-imparting measures (such as adhesive coating or adhesive treatment) to impart adhesion to metal foils or other components, including the addition of the "surface modifier." It is, of course, also possible to obtain a cured product by curing the above-mentioned laminate. The compositions of the present invention, such as the curable compositions, have the properties of a thermoplastic resin.Furthermore, the cured product obtained by curing the curable composition has excellent low dielectric properties, a high storage modulus at high temperatures, and a small thermal expansion coefficient (coefficient of thermal expansion, CTE), making it particularly suitable for use in various electronic substrates.

[0069] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0070] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the descriptions of these examples.

[0071] <Production of Olefin-Aromatic Vinyl Compound-Aromatic Polyene Copolymer> With reference to the production methods described in JP-A-9-40709 and JP-A-9-309925, polymerization was carried out using dimethylmethylenebiscyclopentadienylzirconium dichloride as a catalyst, triisobutylaluminum (TIBAL hexane solution, manufactured by Tosoh Finechem Corporation) as a cocatalyst, and styrene, divinylbenzene, and ethylene as raw materials to obtain an olefin-aromatic vinyl compound-aromatic polyene copolymer (hereinafter referred to as copolymer P1). When the total of the olefin monomer units, the aromatic vinyl compound monomer units, and the aromatic polyene monomer units was 100% by mass, the composition of copolymer P1 was as follows: ethylene content 78% by mass, 1-hexene content 0% by mass, styrene content 20% by mass, and divinylbenzene content 2% by mass. The number average molecular weight Mn of copolymer P1 was 7,500. The water absorption rate of copolymer P1 was less than 0.1%.

[0072] The divinylbenzene used was divinylbenzene (meta-para mixed product, divinylbenzene purity 81%) manufactured by Nippon Steel Chemical & Material Co., Ltd. The curing agent used was Perbutyl P (1,4-bis[(t-butylperoxy)isopropyl]benzene) manufactured by NOF Corporation or Percumyl D (dicumyl peroxide) manufactured by NOF Corporation.

[0073] The content of vinyl group units derived from ethylene, hexene, styrene, and divinylbenzene in the olefin-aromatic vinyl compound-aromatic polyene copolymer is determined by: １ The H-NMR was performed based on the peak area intensity assigned to each component. The sample was dissolved in deuterated 1,1,2,2-tetrachloroethane, and the measurement was carried out at 80 to 130°C. 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: Four TSKgel GMHXL φ7.8 x 300 mm columns (manufactured by Tosoh Corporation) connected in series. Column temperature: 40°C. Solvent: THF. Flow rate: 1.0 ml / min. Detector: RI detector

[0074] <Production of Surface-Treated Silica Powder> (Surface-Treated Silica Powder 1) A silica powder having the particle size distribution shown in Table 1 was prepared. The prepared silica powder was loaded into an alumina crucible and heat-treated in air at 1000°C in an electric furnace for 4 hours. After heat treatment, the mixture was cooled to 200°C in the furnace and then cooled to room temperature in a desiccator (23°C, 10% RH), and the heat-treated silica powder was recovered. 0.4 parts by mass of vinylsilane (KBM-1003, manufactured by Shin-Etsu Silicones Co., Ltd.) was added to 100 parts by mass of the heat-treated silica powder, and the mixture was mixed in a vibration mixer (manufactured by Resodyn) for 30 minutes and then dried at 120°C for 4 hours to obtain Surface-Treated Silica Powder 1.

[0075] (Surface-treated silica powders 2 to 5) Surface-treated silica powder 2 was obtained in the same manner as surface-treated silica powder 1, except that a silica powder having the particle size distribution shown in Table 1 was used and 0.4 parts by mass of methacrylsilane (KBM-503 manufactured by Shin-Etsu Silicones Co., Ltd.) was added instead of vinylsilane per 100 parts by mass of the heat-treated silica powder. Surface-treated silica powder 3 was obtained in the same manner as surface-treated silica powder 1, except that a silica powder having the particle size distribution shown in Table 1 was used and 0.3 parts by mass of vinylsilane was added per 100 parts by mass of the heat-treated silica powder. Surface-treated silica powder 4 was obtained in the same manner as surface-treated silica powder 1, except that a silica powder having the particle size distribution shown in Table 1 was used and 0.1 parts by mass of vinylsilane was added per 100 parts by mass of the heat-treated silica powder. Surface-treated silica powder 5 was obtained in the same manner as surface-treated silica powder 1, except that a silica powder having the particle size distribution shown in Table 1 was used and 0.4 parts by mass of phenylsilane (KBM-103 manufactured by Shin-Etsu Silicones Co., Ltd.) was added instead of vinylsilane per 100 parts by mass of the heat-treated silica powder.

[0076] (Surface-treated silica powder 6) Silica powder having the particle size distribution shown in Table 1 was used, and without heat treatment, 1.1 parts by mass of vinylsilane (manufactured by Shin-Etsu Silicones Co., Ltd.) was added to 100 parts by mass of the prepared silica powder, and the mixture was mixed for 30 minutes in a vibration mixer (manufactured by Resodyn Corporation), followed by drying at 120°C for 4 hours, to obtain surface-treated silica powder 6.

[0077] (Surface-treated silica powder 7) Surface-treated silica powder 7 was obtained in the same manner as surface-treated silica powder 1, except that a silica powder having the particle size distribution shown in Table 1 was used and 1.5 parts by mass of methacrylsilane was added to 100 parts by mass of the heat-treated silica powder.

[0078] (Surface-treated silica powder 8) Surface-treated silica powder 8 was obtained in the same manner as surface-treated silica powder 1, except that a silica powder having the particle size distribution shown in Table 1 was used and 0.6 parts by mass of methacrylsilane (manufactured by Shin-Etsu Silicones Co., Ltd.) was added instead of vinylsilane per 100 parts by mass of the heat-treated silica powder.

[0079] The obtained surface-treated silica powders 1 to 8 were stored in aluminum bags until immediately before various evaluations.

[0080] (Specific Surface Area) The specific surface area of ​​the silica powder was measured by the BET single-point method using nitrogen gas adsorption. Specifically, using a specific surface area measuring device (manufactured by Anton Paar, device name: NOVA 800 BET), nitrogen gas was transported using a vacuum pump, and 0.1 to 5.0 g of the sample was dried and degassed at 300°C for 30 minutes before measurement.

[0081] (Particle size) The volume frequency particle size distribution of silica powder was determined by a wet laser diffraction scattering method using a particle size distribution analyzer (LS13 320, manufactured by Coulter). A 0.2% aqueous solution of sodium hexametaphosphate was used as the solvent, and the powder was pre-treated by dispersing it for 120 seconds or more using a homogenizer at 500 W output. The PIDS (Polarization Intensity Differential Scattering) concentration was adjusted to 45-55% for measurement. The refractive index of water was 1.33, and the refractive index of the powder was determined taking into account the refractive index of the powder material. For example, amorphous silica was measured with a refractive index of 1.50. Based on the obtained volume frequency particle size distribution, the particle size (D Ｘ ) was calculated.

[0082] (Moisture Content) The moisture content in the surface-treated silica powder was measured by the Karl Fischer method. Specifically, a trace moisture analyzer (manufactured by Mitsubishi Chemical Corporation, Model CA-05) was used. The powder was placed in a quartz tube in a moisture vaporization mechanism, and while heating from room temperature to 900°C with an electric heater, dehydrated argon gas was supplied as a carrier gas. Water vapor volatilized from the powder surface was introduced into the moisture measurement mechanism to measure the moisture content. Moisture generated by the time the heating temperature of the electric heater reached 200°C was considered to be physically adsorbed water, moisture generated between 200°C and 550°C was considered to be water derived from hydrogen-bonded OH groups, and moisture generated between 550°C and 900°C was considered to be water resulting from dehydration condensation of isolated OH groups.

[0083] <Production of Resin Composition> The copolymer shown in Table 1 was dissolved in toluene, and 1 part by mass of a curing agent, Perbutyl P (manufactured by NOF Corporation), was added and dissolved per 100 parts by mass of the copolymer, followed by stirring and mixing to obtain a varnish-like composition. The surface-treated silica powder shown in Table 1 was added to the obtained varnish-like composition and stirred to obtain a slurry-like resin composition in which the volume ratio of the copolymer to the surface-treated silica powder was 50 vol%:50 vol%.

[0084]

[0085] The resulting resin compositions were evaluated for the following items.

[0086] <Measurement of dielectric loss tangent>

[0087] The resulting resin composition was stirred using a THINKY MIXER (Thinky Corporation) and then poured onto a PTFE sheet mounted on a silicone rubber mold (frame thickness: 0.5 mm or 1.0 mm) placed on a glass plate. The mixture was then vacuum dried at 80°C for 10 hours at 20 Torr. After completion of the drying process, the silicone rubber mold was replaced with a SUS mold (frame thickness: 0.2 mm). The mixture was sandwiched between PTFE sheets and heated at 200°C for 2 hours under 10 MPa pressure using a heating press to obtain a sheet-like cured product. A 30 mm x 40 mm x 0.2 mm sample was cut from the resulting sheet-like cured product and its dielectric loss tangent at 40 GHz was measured. A 40 GHz split cylinder resonator (EM Lab) was used as the measurement device, and the measurement temperature was 25°C and humidity was 50% RH.

[0088] <Measurement of fluidity> The fluidity was evaluated using the slurry resin composition prepared in the above <Measurement of dielectric tangent>. Using a rheometer (for example, product name "MCR302" manufactured by Anton-Paar), the viscosity was measured at a shear rate of 0.11 / s, plate shape: circular flat plate (10 mmφ), sample thickness: 1 mm, and temperature: 25±1°C. When the viscosity of Example 1 was taken as 100, the fluidity was evaluated according to the following evaluation criteria: Excellent: less than 150 Good: 150 or more but less than 200 Poor: 200 or more

[0089] The results in Table 1 show that the resin compositions of Examples 1 to 5 have a lower dielectric tangent than those of Comparative Examples 1 and 2, and have a higher fluidity than those of Comparative Example 3.

[0090] This application claims priority based on Japanese Patent Application No. 2024-071594, filed April 25, 2024, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A resin composition comprising: an olefin-aromatic vinyl compound-aromatic polyene copolymer; and a surface-treated silica powder, wherein in a volume frequency particle size distribution of the powder measured by a laser diffraction scattering method, the surface-treated silica powder has a ratio (D90-D10) / D50 of 0.8 or more and 4.5 or less, where D10 is the particle diameter at which a cumulative value from the small particle diameter side reaches 10%, D50 is the particle diameter at which a cumulative value reaches 50%, and D90 is the particle diameter at which a cumulative value reaches 90%, and the amount of moisture generated over 550°C to 900°C, as measured by the Karl Fischer method, is 500 ppm or less.

2. The resin composition according to claim 1, wherein the specific surface area of ​​the surface-treated silica powder measured by the BET single-point method using nitrogen gas adsorption is 0.1 m ２ / g or more 12.0m ２ / g or less.

3. A resin composition according to claim 1 or 2, wherein, in the volume frequency particle size distribution of the surface-treated silica powder measured by a laser diffraction scattering method, D50 is defined as the particle size at which the cumulative value from the small particle size side reaches 50%, and D50 of the surface-treated silica powder is 0.1 μm or more and 10 μm or less.

4. The resin composition according to claim 1 or 2, wherein the number average molecular weight Mn of the olefin-aromatic vinyl compound-aromatic polyene copolymer is 500 or more and 100,000 or less.

5. A resin composition according to claim 1 or 2, wherein the olefin-aromatic vinyl compound-aromatic polyene copolymer has a water absorption rate of 1.0% or less.

6. A composite material set comprising a combination of raw material components used to produce a resin composition containing an olefin-aromatic vinyl compound-aromatic polyene copolymer and silica powder, the composite material set comprising: a resin varnish containing an olefin-aromatic vinyl compound-aromatic polyene copolymer and a solvent; and a surface-treated silica powder, wherein in a volume frequency particle size distribution of the powder measured by a laser diffraction scattering method, where D10 is the particle diameter at which a cumulative value from the small particle diameter side reaches 10%, D50 is the particle diameter at which a cumulative value reaches 50%, and D90 is the particle diameter at which a cumulative value reaches 90%, the ratio (D90-D10) / D50 satisfies 0.8 or more and 4.5 or less, and the amount of moisture generated at temperatures exceeding 550°C and reaching 900°C, as measured by the Karl Fischer method, is 500 ppm or less.

Images