Silica for improving transmission loss

Abstract

Provided is silica for improving transmission loss in which the amount of hydroxyl groups per unit weight is 1.0×1017 to 2.5×1018 / g, and the dissipation factor (Df) measured by a perturbation method at room temperature (25° C) and a resonance frequency of 1 GHz is 1.0×10-4 to 5.0×10-3.

Description

Silica improves transmission loss

[0001] The present invention relates to silica that has a reduced dielectric loss tangent, thereby improving transmission loss.

[0002] BACKGROUND ART Filler-containing resin compositions obtained by dispersing a filler material such as silica in a resin material are used in applications requiring insulating properties, such as sealing materials for semiconductor devices, substrate materials, and other electronic materials.

[0003] On the other hand, in electronic materials such as sealing materials for semiconductor devices and substrate materials, a low dielectric dissipation factor is desired depending on the application, and therefore, the filler material contained in the filler-containing resin composition that forms these materials is also desired to have a low dielectric dissipation factor.

[0004] For example, Patent Document 1 discloses a method for producing surface-treated silica having a reduced dielectric loss tangent, which comprises a preparation step of preparing a silica particle material produced by a dry method, and a first surface treatment step of surface-treating the silica particle material with a silane compound having a vinyl group, a phenyl group, a phenylamino group, an alkyl group having 4 or more carbon atoms, a methacryl group, or an epoxy group to obtain a first surface-treated particle material, and wherein the silica particle material is not brought into contact with liquid water after being produced by the dry method. Patent Document 1 also discloses a method for producing surface-treated silica having a particle size of 100 nm to 2000 nm or a specific surface area of ​​2 to 35 m. ２ / g.

[0005] However, although the surface-treated silica obtained by the method of Patent Document 1 can reduce the dielectric loss tangent to some extent in a room temperature and normal humidity environment, the effect of reducing the dielectric loss tangent in a high humidity environment is insufficient. In particular, electronic materials such as sealing materials and substrate materials for semiconductor devices may be used in high humidity environments depending on the application, and it is difficult to say that the surface-treated silica obtained by the method of Patent Document 1 is sufficiently reliable when used in such a high humidity environment. Therefore, there is a demand for a filler material such as silica that has a reduced dielectric loss tangent even when kept in a high humidity environment.

[0006] Japanese Patent Application Laid-Open No. 2020-97498

[0007] An object of the present invention is to provide silica that has a reduced dielectric loss tangent (particularly, the dielectric loss tangent when kept in a high-humidity environment), thereby improving transmission loss (particularly, the transmission loss when kept in a high-humidity environment).

[0008] The present inventors have conducted studies to achieve the above object and have found that the above problems can be solved by using silica having a hydroxyl group content per unit weight within a specific range, thereby completing the present invention.

[0009] That is, according to the present invention, the following silica is provided: [1] The amount of hydroxyl groups per unit weight is 1.0 × 10 １７ ~2.5 x 10 １８ The dielectric loss tangent (Df) measured by a perturbation method at room temperature (25°C) and a resonance frequency of 1 GHz was 1.0 x 10 －４ ~5.0 x 10 －３ [2] The silica according to [1], which has an average particle size of 0.2 to 6 μm and improves transmission loss. [3] The silica according to [1], which has a specific surface area of ​​1 to 20 m ２ [4] The silica for improving transmission loss according to [1] or [2], wherein the bulk density is 0.4 to 1.5 g / cm ３ [5] The silica for improving transmission loss according to any one of [1] to [3], wherein the silica has been subjected to a treatment to reduce surface hydroxyl groups. [6] The silica for improving transmission loss according to [5], wherein the silica has been subjected to a treatment to reduce surface hydroxyl groups, so that the dielectric loss tangent (Df) measured by a perturbation method at room temperature (25°C) and a resonance frequency of 1 GHz is reduced to 90% or less. [7] The silica for improving transmission loss according to [5] or [6], wherein the silica has been subjected to a treatment to reduce surface hydroxyl groups by reacting a hydrosilane compound in a hydrocarbon solvent in the presence of a borane catalyst. [8] The silica for improving transmission loss according to any one of [1] to [7], wherein the silica is a filler for electronic materials.

[0010] According to the present invention, it is possible to provide silica that reduces the dielectric loss tangent (particularly the dielectric loss tangent when kept in a high-humidity environment), thereby improving the transmission loss (particularly the transmission loss when kept in a high-humidity environment).

[0011] The silica of the present invention has a hydroxyl group content of 1.0×10 １７ ~2.5 x 10 １８ The dielectric loss tangent (Df) measured by a perturbation method at room temperature (25°C) and a resonance frequency of 1 GHz is 1.0 x 10 －４ ~5.0 x 10 －３ is silica, which improves transmission loss.

[0012] The amount of hydroxyl groups per unit weight of the silica of the present invention is 1.0×10 １７ ~2.5 x 10 １８ The range of particles / g is sufficient, but the lower limit is preferably 2.5 × 10 １７ More preferably, 5.0 × 10 １７ The upper limit is preferably 2.5 × 10 １８ or less, more preferably 2.0 × 10 １８ More preferably, 1.0 × 10 １８ As a result of extensive investigations, the present inventors have found that silica in which the amount of hydroxyl groups per unit weight is controlled within the above range can reduce the dielectric loss tangent, particularly the dielectric loss tangent when kept in a high-humidity environment, thereby improving transmission loss (particularly the transmission loss when kept in a high-humidity environment), and can be suitably used in electronic materials such as encapsulants for semiconductor devices and substrate materials, particularly as a filler material contained in a filler-containing resin composition for constituting electronic materials such as encapsulants for semiconductor devices and substrate materials.

[0013] In the silica of the present invention, the amount of hydroxyl groups per unit weight is determined, for example, by the Sears method as the content of hydroxyl groups per unit surface area (number / nm ２ ) was measured, and the content of hydroxyl groups per unit surface area (number / nm ２ ) and the specific surface area of ​​silica (nm ２ / g) to obtain the value.

[0014] Measurement by the Sears method can be carried out with reference to "G.W. Sears, Jr., Analytical Chemistry, Vol. 28, No. 12, pp. 1981-1983 (1956)." Specifically, an aqueous solution of silica prepared at a concentration of 1 wt % is titrated with a 0.1 mol / L NaOH aqueous solution at a drop rate of 2 mL / min, and the hydroxyl group content per unit surface area of ​​the silica can be calculated based on the following formula: ρ=(a×b×N Ａ ) ÷ (c × d) ρ: Content of hydroxyl groups per unit surface area of ​​silica (number / nm ２ a: Concentration of the NaOH aqueous solution used for titration (mol / L) b: Amount of NaOH solution of pH 4 to 9 added (mL) N Ａ : Avogadro's number c: weight of silica (g) d: specific surface area of ​​silica (nm ２ / g)

[0015] The content of hydroxyl groups per unit surface area of ​​the silica of the present invention is not particularly limited, but is preferably 0.01 to 2.0 groups / nm ２ The lower limit is more preferably 0.05 particles / nm ２ More preferably, 0.1 particles / nm ２ The upper limit is more preferably 1.5 particles / nm ２ More preferably, 1.25 particles / nm or less ２ or less, and even more preferably 0.6 particles / nm ２ Particularly preferably 0.15 particles / nm or less ２ The content of hydroxyl groups per unit surface area of ​​silica can be measured by the Sears method described above.

[0016] In the present invention, the method for adjusting the amount of hydroxyl groups per unit weight of silica to fall within the above-mentioned range is not particularly limited, and examples thereof include a method of subjecting silica to a treatment to reduce the surface hydroxyl groups contained therein. The method for performing the treatment to reduce the surface hydroxyl groups is not particularly limited as long as it is a method that can adjust the amount of hydroxyl groups per unit weight of silica to fall within the above-mentioned range, and examples thereof include a method of performing a hydrosilanization treatment using a hydrosilane compound. According to the hydrosilanization treatment, the surface hydroxyl groups of the silica undergo a dehydrocondensation reaction with the hydrosilane compound, thereby capping the surface hydroxyl groups of the silica, and thereby appropriately reducing the surface hydroxyl groups of the silica.

[0017] The method for subjecting silica to hydrosilanization treatment is not particularly limited, but a suitable example is a method in which silica is reacted with a hydrosilane compound in a hydrocarbon solvent in the presence of a catalyst.

[0018] The hydrosilane compound is not particularly limited as long as it has a Si—H group in which a hydrogen atom is bonded to a silicon atom, and either a hydrosilane compound having one Si—H group or a hydrosilane compound having two or more Si—H groups can be used. However, from the viewpoints of enabling the content of hydroxyl groups per unit surface area of ​​silica to be suitably controlled within the above-mentioned range and enabling a further reduction in the dielectric loss tangent when the compound is maintained in a high-humidity environment, a hydrosilane compound having one Si—H group is preferred.

[0019] An example of a hydrosilane compound having one Si—H group is a hydrosilane compound represented by the following general formula (1): １ R ２ R ３ SiH (1) (wherein R １ ~R ３ each independently represents a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent.

[0020] In the above general formula (1), R １ ~R ３are each independently a monovalent hydrocarbon group having 1 to 10 carbon atoms which may have a substituent. Specific examples include linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, and octyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl and tolyl; and aralkyl groups such as benzyl, phenylethyl, and phenylpropyl.

[0021] Specific examples of the hydrosilane compound represented by general formula (1) include trialkylhydrosilanes such as trimethylsilane, triethylsilane, tripropylsilane, tributylsilane, trioctylsilane, and t-butyldimethylsilane; dialkylarylhydrosilanes such as phenyldimethylsilane, phenyldiethylsilane, phenyldipropylsilane, phenyldioctylsilane, o-chlorophenyldimethylsilane, m-chlorophenyldimethylsilane, p-chlorophenyldimethylsilane, p-fluorophenyldimethylsilane, p-bromophenyldimethylsilane, p-methylphenyldimethylsilane, p-butylphenyldimethylsilane, p-octylphenyldimethylsilane, p-methoxyphenyldimethylsilane, and p-butoxyphenyldimethylsilane; and methyldiphenylsilane. alkyldiarylhydrosilanes such as nylsilane, ethyldiphenylsilane, propyldiphenylsilane, octyldiphenylsilane, methyldi(p-chlorophenyl)silane, methyldi(p-bromophenyl)silane, methyldi(p-fluorophenyl)silane, methyldi(p-methylphenyl)silane, methyldi(p-butylphenyl)silane, methyldi(p-octylphenyl)silane, methyldi(p-methoxyphenyl)silane, and methyldi(p-butoxyphenyl)silane; triarylhydrosilanes such as triphenylsilane, tri(p-chlorophenyl)silane, tri(p-bromophenyl)silane, tri(p-fluorophenyl)silane, tri(p-methylphenyl)silane, tri(p-butylphenyl)silane, and tri(p-octylphenyl)silane; and the like. These may be used alone or in combination of two or more.

[0022] In the above general formula (1), R １ ~R ３ From the viewpoint that the content of hydroxyl groups per unit surface area of ​​silica can be suitably controlled within the above range, R １ ~R ３ In other words, the hydrosilane compound represented by the general formula (1) is preferably a trialkylhydrosilane. From the viewpoint of suitably controlling the content of hydroxyl groups per unit surface area of ​​silica within the above range, R １ ~R ３ are preferably all the same group (i.e., R １ =R ２ =R ３ is preferred).

[0023] The hydrosilane compound represented by general formula (1) is preferably trimethylsilane, triethylsilane, tripropylsilane, tributylsilane, trioctylsilane, or t-butyldimethylsilane, more preferably trimethylsilane, triethylsilane, tripropylsilane, or tributylsilane, still more preferably trimethylsilane or triethylsilane, and particularly preferably triethylsilane.

[0024] The amount of the hydrosilane compound used is preferably 0.01 to 1.0 part by weight, more preferably 0.1 to 0.8 part by weight, and even more preferably 0.15 to 0.7 part by weight, per 100 parts by weight of silica used in the reaction.

[0025] Examples of the catalyst include platinum catalysts such as Kastredt's catalyst (platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex), Speier's catalyst, Wilkinson's catalyst, Trost's catalyst, and tris(pentafluorophenyl)borane (B(C ６ F ５ ) ３These may be used alone or in combination of two or more. Among these, from the viewpoint of economy and the ability to suitably control the content of hydroxyl groups per unit surface area of ​​silica within the above-mentioned range, borane catalysts are preferred, and tris(pentafluorophenyl)borane is more preferred.

[0026] The amount of the catalyst used is preferably 0.0003 to 0.1 part by weight, more preferably 0.001 to 0.05 part by weight, and even more preferably 0.01 to 0.05 part by weight, per 100 parts by weight of the hydrosilane compound used in the reaction.

[0027] The hydrocarbon solvent is not particularly limited as long as it does not inhibit the dehydrogenative condensation reaction between the surface hydroxyl groups of silica and the hydrosilane compound. Examples of the hydrocarbon solvent include alkanes such as hexane, octane, decane, and dodecane; cycloalkanes such as cyclohexane; halogenated solvents such as dichloromethane and dichloroethane; aromatic hydrocarbons such as toluene, xylene, and benzene; and alkyl and aryl ether solvents such as diethyl ether, tetrahydrofuran (THF), dioxane, cyclopentyl methyl ether, and diphenyl ether. These solvents can be used alone or in combination of two or more. Nonpolar hydrocarbon solvents can also be used. Examples of nonpolar hydrocarbon solvents include cycloalkanes and aromatic hydrocarbons, more preferably toluene, benzene, and cyclohexane, even more preferably toluene and cyclohexane, and particularly preferably cyclohexane. Furthermore, halogenated solvents can also be used as the hydrocarbon solvent, with dichloromethane being more preferred.

[0028] The amount of the hydrocarbon solvent used is preferably 0.4 to 10 parts by weight, more preferably 0.5 to 7.5 parts by weight, and even more preferably 0.75 to 5 parts by weight, per 100 parts by weight of silica used in the reaction.

[0029] In the present invention, the silica used as a raw material for the hydrosilanization treatment is not particularly limited, and may be silica obtained by any of the sol-gel method, the deflagration method, the wet method, and the fusion method, and is not particularly limited. Furthermore, the silica used as a raw material for the hydrosilanization treatment may be untreated silica that has not been surface-treated, or may be surface-treated silica that has been surface-treated. For example, the silica used as a raw material for the hydrosilanization treatment may be silica having a dielectric loss tangent (Df) of 1.0 × 10 －６ ~5.0 x 10 －３ It is preferable that the range is 1.0 × 10 －６ ~3.0 x 10 －３ More preferably, it is in the range of 1.0 × 10 －６ ~1.0 x 10 －３ More preferably, it is in the range of 1.0 × 10 －６ ~5.0 x 10 －４ The dielectric loss tangent (Df) of silica, which is a raw material to be subjected to the hydrosilanization treatment, can be measured by a perturbation method using silica after storage for 24 hours under room temperature (25°C) and low humidity conditions of 1% RH or less, using a cavity resonator perturbation dielectric constant measurement device at room temperature (25°C) and a resonant frequency of 1 GHz.

[0030] The hydrosilanization treatment can be carried out, for example, by adding a catalyst such as a borane catalyst to a dispersion or solution obtained by dispersing or dissolving silica and a hydrosilane compound in a hydrocarbon solvent. The reaction may be carried out under stirring using a stirring device or the like. The reaction temperature is preferably 0 to 60°C, more preferably 5 to 50°C, and the reaction time is preferably 10 to 600 minutes, more preferably 30 to 180 minutes. Note that, since hydrogen gas is generated as the hydrosilanization reaction proceeds, the reaction time may be adjusted appropriately by checking whether or not hydrogen gas is generated.

[0031] Silica can be subjected to a hydrosilanization treatment according to the above method. The obtained hydrosilanized silica may be washed with a hydrocarbon solvent and dried, as necessary. In this case, the hydrocarbon solvent may be any of those described above.

[0032] The average particle size of the silica of the present invention is not particularly limited, but is preferably 0.2 to 6 μm, more preferably 0.3 to 5 μm, even more preferably 0.4 to 4 μm, and even more preferably 0.5 to 3 μm. By having the average particle size of silica within the above range, the effect of reducing the dielectric loss tangent when maintained in a high-humidity environment can be further enhanced. The average particle size of silica can be measured, for example, as the 50% cumulative diameter (D50 diameter) on a volume basis using a laser diffraction scattering measurement device.

[0033] The specific surface area of ​​the silica of the present invention is not particularly limited, but is preferably 1 to 20 m ２ / g, more preferably 1 to 18m ２ / g, more preferably 1.5 to 17.5 m ２ / g. When the specific surface area of ​​silica is within the above range, the effect of reducing the dielectric loss tangent when the silica is kept in a high humidity environment can be further enhanced. The specific surface area of ​​silica can be measured, for example, by the BET method in accordance with ASTM D3037-81.

[0034] The bulk density of the silica of the present invention is not particularly limited, but is preferably 0.4 to 3 g / cm ３ and more preferably 1 to 2.8 g / cm ３ , more preferably 1.5 to 2.5 g / cm ３ is.

[0035] The silica of the present invention has a dielectric loss tangent (Df) of 1.0×10 measured by a perturbation method at room temperature (25° C.) and a resonance frequency of 1 GHz. －４ ~5.0 x 10 －３ and preferably 1.0 × 10 －４ ~2.0 x 10 －３ and more preferably 1.2 × 10 －４ ~1.0 x 10―３ , and more preferably 1.4 × 10 －４ ~8.0 x 10 －４ The dielectric loss tangent (Df) of silica can be measured by a perturbation method using silica that has been stored for 24 hours under normal temperature and low humidity conditions of 25°C and 1% RH or less, using a cavity resonator perturbation dielectric constant measuring device at room temperature (25°C) and a resonant frequency of 1 GHz.

[0036] Furthermore, the silica of the present invention has a dielectric loss tangent (Df) after storage under high humidity conditions (dielectric loss tangent (Df) after storage for 24 hours under conditions of 30°C and 80% RH) of 2.5 x 10 －４ ~1.0 x 10 －３ It is preferable that the －４ ~9.8 x 10 －４ The dielectric loss tangent (Df) after storage under high humidity conditions can be measured by storing silica at 30°C and 80% RH for 24 hours, and then measuring it by a cavity resonator perturbation dielectric constant measuring device at room temperature (25°C) and a resonant frequency of 1 GHz using a perturbation method.

[0037] Furthermore, by subjecting the silica of the present invention to the above-mentioned treatment for reducing the number of surface hydroxyl groups (for example, hydrosilanization treatment), the value of the dielectric loss tangent (Df) measured by a perturbation method at room temperature (25°C) and a resonance frequency of 1 GHz (i.e., the value calculated as "(dielectric loss tangent (Df) after the treatment for reducing the number of surface hydroxyl groups / dielectric loss tangent (Df) before the treatment for reducing the number of surface hydroxyl groups) × 100") is preferably reduced to 30% or more, more preferably 35 to 95%, and even more preferably 45 to 90%.

[0038] Furthermore, the silica of the present invention may be treated with a silane coupling agent, if necessary. Known silane coupling agents can be used as the silane coupling agent, but alkoxysilanes are preferred. Examples of alkoxysilanes include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-aminoethylgammaaminopropyltrimethoxysilane, N-β-aminoethylgammaaminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, and trifluoropropyltrimethoxysilane. The silane coupling agents can be used alone or in combination of two or more.

[0039] The silica of the present invention has a hydroxyl group content of 1.0×10 １７ ~2.5 x 10 １８ The silica of the present invention has a density controlled within the range of 1000 particles / g, a reduced dielectric loss tangent, and in particular a reduced dielectric loss tangent when maintained in a high humidity environment. Therefore, the silica of the present invention can be suitably used as a filler material for electronic materials, and more specifically, can be suitably used as a filler material to be contained in a filler-containing resin composition for electronic materials.

[0040] When the silica of the present invention is used as a filler material to be contained in a filler-containing resin composition for electronic materials, the silica of the present invention is mixed into a resin material, thereby making it possible to prepare a filler-containing resin composition.

[0041] The resin material used to obtain the filler-containing resin composition is not particularly limited, and may be either a thermosetting resin or a thermoplastic resin, such as an epoxy resin, a melamine resin, an acrylic resin, a polycarbonate resin, a polyester, a silicone resin, a liquid crystal polymer (LCP), a polyimide resin, a maleimide resin, a polyphenylene ether resin, a fluororesin, a cyclic olefin polymer (COP), or a polyphenylene oxide (PPO).

[0042] The ratio of silica to resin material in the filler-containing resin composition for electronic materials is not particularly limited, but is preferably 1:99 to 95:5, and more preferably 10:90 to 80:20, in terms of weight ratio of silica to resin material.

[0043] Specific examples of electronic materials in which the silica of the present invention is used as a filler for electronic materials include, but are not limited to, encapsulants for semiconductor devices, substrate materials, high-frequency electronic substrate materials, and insulating materials for semiconductors. In particular, the silica of the present invention has a reduced dielectric loss tangent when maintained in a high-humidity environment, and is therefore suitable for use as a substrate material for printed wiring boards and the like, particularly as a material for forming the insulating layer of a copper-clad laminate. For example, when used as an insulating layer for a copper-clad laminate, a filler-containing resin composition for electronic materials containing the silica of the present invention and a resin material may be prepared, and the prepared filler-containing resin composition may be molded to form the insulating layer of the copper-clad laminate. Alternatively, the prepared filler-containing resin composition may be impregnated into or composited with a fiber material or the like to form a prepreg, and the prepreg may be used to form the insulating layer of the copper-clad laminate.

[0044] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The terms "parts" are based on mass unless otherwise specified. The test methods used in these examples and comparative examples are as follows.

[0045] <Hydroxyl Group Content per Unit Surface Area of ​​Silica> The hydroxyl group content per unit surface area of ​​silica was measured by the Sears method. Measurement by the Sears method was performed with reference to "G.W. Sears, Jr., Analytical Chemistry, Vol. 28, No. 12, pp. 1981-1983 (1956)." Specifically, 120 mL of methanol, 100 mL of distilled water, and 25 g of sodium chloride were added to 2.50 g of silica, and then a dispersion treatment was carried out using an ultrasonic bath, a homomixer, or a disper to prepare a slurry, and then 25 g of sodium chloride was added to prepare a silica slurry. This silica slurry was titrated using a 0.1 mol / L or 0.01 mol / L aqueous NaOH solution, and the hydroxyl group content per unit surface area of ​​silica was calculated based on the following formula: ρ=(a×b×N Ａ ) ÷ (c × d) ρ: Content of hydroxyl groups per unit surface area of ​​silica (number / nm ２ a: Concentration of the NaOH aqueous solution used for titration (mol / L) b: Amount of NaOH solution of pH 4 to 9 added (mL) N Ａ : Avogadro's number c: weight of silica (g) d: BET specific surface area of ​​silica (nm ２ / g)

[0046] <Hydroxyl group content per unit weight of silica> The hydroxyl group content (number / g) per unit weight of silica is the content of hydroxyl groups per unit surface area of ​​silica (number / nm²) determined by the Sears method. ２ ) and the specific surface area of ​​silica (nm ２ / g).

[0047] <Rate of change in amount of hydroxyl groups before and after treatment to reduce surface hydroxyl groups> The rate of change in amount of hydroxyl groups before and after treatment to reduce surface hydroxyl groups was calculated by the formula "hydroxyl group content per unit weight of silica after treatment to reduce surface hydroxyl groups / hydroxyl group content per unit weight of untreated silica that has not been treated to reduce surface hydroxyl groups."

[0048] <Electrical Properties at Room Temperature and Humidity> After storing silica for 24 hours under room temperature and humidity conditions of 25°C and 30 to 50% RH, the relative permittivity and dielectric loss tangent at a frequency of 1 GHz were measured using a perturbation type measuring device (manufactured by AET Co., Ltd., model: ADMS01Nc).

[0049] <Electrical Properties After Drying Treatment> Silica was dried for 24 hours using a drying apparatus (manufactured by ERC Corporation, apparatus name: Mac Dry) under conditions of 25°C and 1% RH or less, and then the relative permittivity and dielectric loss tangent at a frequency of 1 GHz were measured using a perturbation type measuring apparatus (manufactured by AET Co., Ltd., model: ADMS01Nc) using the dried silica.

[0050] <Electrical Properties After Storage Under High-Humidity Conditions> Silica was stored under high-humidity conditions of 30°C and 80% RH for 24 hours, and then the relative permittivity and dielectric loss tangent at a frequency of 1 GHz were measured using a perturbation-type measuring device (manufactured by AET Co., Ltd., model: ADMS01Nc) for the silica that had been stored under high-humidity conditions.

[0051] Example 1 Silica (trade name "SFP-130MC", manufactured by Denka Co., Ltd., average particle diameter (D50 diameter): 0.7 μm, BET specific surface area: 6.1 m) was placed in a reaction vessel equipped with a stirrer and placed in a nitrogen atmosphere. ２ / g), 274 parts of cyclohexane, and triethylsilane (Et ３ 39.1 parts of trispentafluorophenylborane (B(C ６ F ５ ) ３ A solution of 1.7 parts of tris(pentafluorophenyl)borane (B(C)) in 17 parts of toluene was added. ６ F ５ ) ３ After the reaction was started, stirring was continued for 60 minutes. After the reaction was started, the generation of hydrogen was stopped and the completion of the reaction was confirmed. After that, the silica after the reaction was thoroughly washed with toluene and then dried under reduced pressure at room temperature for 2 hours. ３The hydrosilanized silica was obtained by subjecting the surface hydroxyl group reduction treatment to triethylsilane (Et ３ The average particle size and BET specific surface area of ​​hydrosilanized silica, which has been treated to reduce the surface hydroxyl groups with triethylsilane (Et ３ No change was observed before and after the hydrosilation treatment with SiH (the same applies to Examples 2 to 7 described below).

[0052] Comparative Example 1 Silica (product name "SFP-130MC", manufactured by Denka Co., Ltd.) was used as it was without any treatment and was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0053] Comparative Example 2 Silica (product name "SFP-130MC", manufactured by Denka Co., Ltd.) was washed only with cyclohexane and toluene, and the washed silica was used to perform evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0054] Example 2 Instead of silica (trade name "SFP-130MC", manufactured by Denka Co., Ltd.), silica (trade name "GT130MC", manufactured by Denka Co., Ltd., average particle diameter (D50 diameter): 0.7 μm, BET specific surface area: 5.9 m) was used. ２ The same procedure as in Example 1 was repeated except that triethylsilane (Et ３ The surface hydroxyl groups were reduced by a hydrosilanization treatment using HCl (SiH) to obtain hydrosilanized silica, which was then evaluated in the same manner. The results are shown in Table 1.

[0055] Comparative Example 3 Silica (trade name "GT130MC", manufactured by Denka Co., Ltd.) was used as it was without any treatment and was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0056] Comparative Example 4 Silica (trade name "GT130MC", manufactured by Denka Co., Ltd.) was washed only with cyclohexane and toluene, and the washed silica was used to perform evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0057] Example 3 Instead of silica (trade name "SFP-130MC", manufactured by Denka Co., Ltd.), silica (trade name "GT3SDC", manufactured by Denka Co., Ltd., average particle diameter (D50 diameter): 3 μm, BET specific surface area: 3.3 m ２ The same procedure as in Example 1 was repeated except that triethylsilane (Et ３ The surface hydroxyl groups were reduced by a hydrosilanization treatment using HCl (SiH) to obtain hydrosilanized silica, which was then evaluated in the same manner. The results are shown in Table 1.

[0058] Comparative Example 5 Silica (trade name "GT3SDC", manufactured by Denka Co., Ltd.) was used as it was without any treatment and was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0059] Comparative Example 6 Silica (trade name "GT3SDC", manufactured by Denka Company Ltd.) was washed only with cyclohexane and toluene, and the washed silica was used to perform evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0060] Example 4 Instead of silica (trade name "SFP-130MC", manufactured by Denka Co., Ltd.), silica (trade name "GT5SDC", manufactured by Denka Co., Ltd., average particle diameter (D50 diameter): 5 μm, BET specific surface area: 1.8 m ２ The same procedure as in Example 1 was repeated except that triethylsilane (Et ３ The surface hydroxyl groups were reduced by a hydrosilanization treatment using HCl (SiH) to obtain hydrosilanized silica, which was then evaluated in the same manner. The results are shown in Table 1.

[0061] Comparative Example 7 Silica (trade name "GT5SDC", manufactured by Denka Co., Ltd.) was used as it was without any treatment and was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0062] Comparative Example 8 Silica (trade name "GT5SDC", manufactured by Denka Company Ltd.) was washed only with cyclohexane and toluene, and the washed silica was used to perform evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0063] Example 5 Instead of silica (product name "SFP-130MC", manufactured by Denka Co., Ltd.), silica (product name "3SV-C1", manufactured by Admatechs Co., Ltd., average particle diameter (D50 diameter): 0.3 μm, BET specific surface area: 16.4 m ２ The same procedure as in Example 1 was repeated except that triethylsilane (Et ３ The surface hydroxyl groups were reduced by a hydrosilanization treatment using HCl (SiH) to obtain hydrosilanized silica, which was then evaluated in the same manner. The results are shown in Table 1.

[0064] Comparative Example 9 Silica (product name "3SV-C1", manufactured by Admatechs Co., Ltd.) was used as it was without any treatment and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0065] Comparative Example 10 Silica (product name "3SV-C1", manufactured by Admatechs Co., Ltd.) was washed only with cyclohexane and toluene, and the washed silica was used to perform evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0066] Example 6 Instead of silica (product name "SFP-130MC", manufactured by Denka Co., Ltd.), silica (product name "3SV-C3", manufactured by Admatechs Co., Ltd., average particle diameter (D50 diameter): 0.3 μm, BET specific surface area: 16.4 m ２ The same procedure as in Example 1 was repeated except that triethylsilane (Et ３ The surface hydroxyl groups were reduced by a hydrosilanization treatment using HCl (SiH) to obtain hydrosilanized silica, which was then evaluated in the same manner. The results are shown in Table 1.

[0067] Comparative Example 11 Silica (product name "3SV-C3", manufactured by Admatechs Co., Ltd.) was used as it was without any treatment and was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0068] Comparative Example 12 Silica (product name "3SV-C3", manufactured by Admatechs Co., Ltd.) was washed only with cyclohexane and toluene, and the washed silica was used to perform evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0069] Example 7: Triethylsilane (Et ３ A hydrosilanized silica was obtained in which the surface hydroxyl groups had been reduced with t-butyldimethylsilane (t-BDS) in the same manner as in Example 1, except that 39.1 parts of t-butyldimethylsilane (t-BDS) was used instead of 39.1 parts of t-butyldimethylsilane (t-BDS). The hydrosilanized silica was then evaluated in the same manner. The results are shown in Table 1.

[0070] In Table 1, "αE+β" means "α×10 β ", and the description "αE-β" means "α×10 －β For example, the value of the hydroxyl group content per unit weight in Example 1, "1.74E+18", means "1.74 x 10 １８ ", and the value of the dielectric loss tangent (Df) in the electrical properties under normal temperature and humidity conditions in Example 1, "5.02E-04", means "5.02 × 10 －４ " means.

[0071] As shown in Table 1, the amount of hydroxyl groups per unit weight was 1.0×10 １７ ~2.5 x 10 １８ Silica having a hydroxyl group content of 2.5×10 １８ The dielectric loss tangent (Df) was reduced compared to silica having a hydroxyl group content of more than 1.0 × 10 per unit weight, and in particular, the dielectric loss tangent (Df) after storage under high humidity conditions (dielectric loss tangent (Df) after storage for 24 hours under conditions of 30°C and 80% RH) was kept low, thereby making it possible to improve the transmission loss (particularly, the transmission loss after storage under high humidity conditions) (Examples 1 to 7). １７ ~2.5 x 10 １８When silica having a density of particles / g is used as a filler material for electronic materials and mixed with a resin material to form a filler-containing resin composition for electronic materials, it can be said that an insulating layer having a reduced dielectric loss tangent and thus improved transmission loss can be provided, particularly an insulating layer having a reduced dielectric loss tangent when kept in a high-humidity environment and thus improved transmission loss.

Claims

1. The amount of hydroxyl groups per unit weight is 1.0 x 10 １７ ~2.5 x 10 １８ The dielectric loss tangent (Df) measured by the perturbation method at room temperature (25° C.) and a resonant frequency of 1 GHz is 1.0×10 －４ ~5.0 x 10 －３ Silica improves transmission loss.

2. The silica for improving transmission loss according to claim 1, having an average particle size of 0.2 to 6 μm.

3. Specific surface area is 1 to 20 m ２ 3. The method for improving transmission loss according to claim 1 or 2, wherein the silica has a refractive index of 1 / g.

4. Bulk density is 0.4 to 1.5 g / cm ３ The silica for improving transmission loss according to any one of claims 1 to 3, wherein 5. The silica for improving transmission loss according to any one of claims 1 to 4, wherein the silica has been subjected to a treatment to reduce surface hydroxyl groups.

6. A silica for improving transmission loss as described in claim 5, in which the silica has been subjected to a treatment to reduce surface hydroxyl groups, thereby reducing the dielectric tangent (Df) value measured by a perturbation method at room temperature (25°C) and a resonant frequency of 1 GHz to 90% or less.

7. The silica for improving transmission loss according to claim 5 or 6, wherein the silica has been subjected to a treatment for reducing surface hydroxyl groups by reacting a hydrosilane compound in a hydrocarbon solvent in the presence of a borane catalyst.

8. The silica for improving transmission loss according to any one of claims 1 to 7, which is a filler for electronic materials.

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