Filler for electronic materials, method for producing filler for electronic materials, filler-containing resin composition for electronic materials, and slurry for electronic materials

Abstract

To provide a filler for electronic materials which can suppress dielectric tangent while maintaining high permittivity as a filler by using strontium titanate or calcium titanate, a method for producing the filler for electronic materials, a resin composition containing the filler for electronic materials, and a slurry for electronic materials.SOLUTION: A filler for electronic materials comprises a base material part consisting mainly of strontium titanate or calcium titanate, and a coating part formed by a coupling agent present on a surface of the base materia. In the filler for electronic materials, a ratio (Rw) between an amount of carbon (C2(%)) derived from a chemical bond surface treatment agent after cleaning and an amount of carbon (C1(%)) derived from the surface treatment agent before cleaning satisfies the range of 0.1 to 1.0.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filler for electronic materials, a method for producing a filler for electronic materials, a filler-containing resin composition for electronic materials, and a slurry for electronic materials. [Background technology]

[0002] The trend toward improved transmission speeds and larger capacities in communication terminals used for wireless transmission has led to the use of higher frequency radio wave bands. However, as frequencies increase, the amount of power attenuation per unit length of radio waves (electromagnetic waves), i.e., transmission loss, increases. Transmission loss is significantly affected by the dielectric loss tangent (dielectric loss), which is the loss that occurs when electromagnetic waves propagate through a dielectric. For this reason, fillers used in electronic components for large-capacity, high-speed communication in communication terminals, passenger cars, etc., as well as in their sealants, are required to have the ability to suppress the dielectric loss tangent.

[0003] Generally, fillers added to small electronic components or their sealants are preferably made of materials with high dielectric constants. However, the high dielectric constant of the filler itself increases the dielectric loss tangent. Thus, the filler is required to have the contradictory properties of high dielectric constant and low dielectric loss tangent.

[0004] Furthermore, since fillers are added to resins, the fillers are required to have the fluidity and adhesiveness of the resin after addition. To increase the dielectric constant of resins used in electronic components or their sealants, the amount of filler added to the resin also increases. Therefore, the decrease in fluidity due to the increase in viscosity of the resin is undesirable because it reduces work efficiency.

[0005] In addition, strontium titanate and calcium titanate have high dielectric constants, making them promising compounds for use as fillers (see Patent Document 1, etc.). However, basic components eluted from these compounds may cause poor curing of the resin. Furthermore, the problems of suppressing high dielectric constants and dielectric loss tangents have not yet been resolved. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. WO2019 / 123916 Summary of the Invention [Problem to be solved by the invention]

[0007] Subsequently, the inventors conducted extensive research and found that, while using compounds such as strontium titanate and calcium titanate, which have good dielectric constants, the dielectric dissipation factor of the filler can be suppressed by appropriately processing the surface of the compound.

[0008] The present invention has been made in view of the above points, and provides a filler for electronic materials that uses strontium titanate or calcium titanate and that can suppress the dielectric loss tangent while maintaining a high dielectric constant as a filler, a method for producing the filler for electronic materials, a filler-containing resin composition for electronic materials, and a slurry for electronic materials. [Means for solving the problem]

[0009] That is, the filler for electronic materials of the embodiment is a filler for electronic materials comprising a substrate portion mainly composed of strontium titanate or calcium titanate, and a coating portion formed by a coupling agent present on the surface of the substrate portion, and is characterized in that in the following measurement (I) of the amount of carbon derived from a chemically bonded surface treatment agent after cleaning, the ratio (Rw) of the amount of carbon derived from a chemically bonded surface treatment agent after cleaning (C2 (%)) / the amount of carbon derived from a surface treatment agent before cleaning (C1 (%)) represented by formula (i) satisfies the range of 0.1 to 1.0.

[0010]

number

[0011] Measurement of the amount of carbon after cleaning derived from the chemically bonded surface treatment agent (I) involves adding 35 g of methyl ethyl ketone to 5 g of electronic material filler, shaking and leaving to stand for 10 minutes, and then performing solid-liquid separation using a centrifuge to obtain a sediment. The supernatant is then discarded, and 35 g of methyl ethyl ketone is added to 5 g of the sediment, shaking and leaving to stand for 10 minutes, and then performing solid-liquid separation using a centrifuge to obtain a sediment that is then dried. The amount of carbon in the dried sediment is measured as the amount of carbon after cleaning derived from the chemically bonded surface treatment agent.

[0012] Furthermore, in the filler for electronic materials, the volume average particle size of the base portion may be in the range of 0.1 to 3 μm.

[0013] Furthermore, in the filler for electronic materials, the coupling agent may be a silane-based coupling agent, a titanium-based coupling agent, or an aluminate-based coupling agent.

[0014] Furthermore, the filler for electronic materials may have a dielectric loss tangent of 0.04 or less at 1 GHz according to JIS C 2138 (2007).

[0015] Furthermore, the specific surface area (Fs( m 2 The chemical bond amount (reaction amount) of the surface treatment agent calculated from the amount of carbon after cleaning derived from the chemical bond surface treatment agent per m 2 The range may be satisfied.

[0016] Furthermore, the filler for electronic materials may have a viscosity of 500 Pa·s or less after being kneaded with a liquid epoxy resin in the next viscosity measurement (II).

[0017] For viscosity measurement (II), when the main component of the substrate is strontium titanate, 32.5 g of electronic material filler is mixed and kneaded with 17.5 g of liquid epoxy resin (1900 to 2600 mPa·s), or when the main component of the substrate is calcium titanate, 29.75 g of electronic material filler is mixed and kneaded with 20.25 g of liquid epoxy resin (1900 to 2600 mPa·s), and each is aged at 80°C for 1 hour to prepare a viscosity measurement varnish, and the viscosity of the viscosity measurement varnish at 25°C is measured using an E-type viscometer.

[0018] Furthermore, the pH of the water used to extract the filler for electronic materials may be in the range of 5 to 9.5.

[0019] Furthermore, in the filler for electronic materials, the coating portion may contain a silicon compound.

[0020] The method for producing a filler for electronic materials is characterized by comprising a contacting step of bringing a coupling agent into contact with the surface of a substrate mainly composed of strontium titanate or calcium titanate, and a heating step of heating the substrate with which the coupling agent has come into contact.

[0021] Furthermore, in the above-described method for producing a filler for electronic materials, the coupling agent may be a silane-based coupling agent or a titanium-based coupling agent.

[0022] Furthermore, in the method for producing a filler for electronic materials, the heating step may be performed at 200° C. or less.

[0023] Furthermore, the method for producing a filler for electronic materials may include a silicon compound adding step of adding a silicon compound between the contacting step and the heating step.

[0024] The filler-containing resin composition for electronic materials is characterized by containing a filler for electronic materials in a resin, and the slurry for electronic materials is characterized by having the filler for electronic materials and a liquid dispersion medium that disperses the filler for electronic materials and is substantially free of water. [Effects of the Invention]

[0025] The filler for electronic materials of the present invention comprises a substrate primarily composed of strontium titanate or calcium titanate and a coating formed by a coupling agent present on the surface of the substrate. The filler for electronic materials has a ratio (Rw) of the amount of carbon derived from the chemically bonded surface treatment agent after cleaning (C2 (%)) to the amount of carbon derived from the surface treatment agent before cleaning (C1 (%)) in the range of 0.1 to 1.0. Therefore, the filler can be made using strontium titanate or calcium titanate to maintain a high dielectric constant while suppressing the dielectric loss tangent. Furthermore, the method for producing a filler for electronic materials of the present invention can be used to produce a filler that maintains a high dielectric constant while suppressing the dielectric loss tangent. Furthermore, by forming the filler into a filler-containing resin composition for electronic materials or a slurry for electronic materials, a suitable composition or slurry for electronic materials can be obtained. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is an electron microscope photograph of an example of a filler for electronic materials according to an embodiment. [Figure 2] 1 is an electron microscope photograph of a substrate portion. DETAILED DESCRIPTION OF THE INVENTION

[0027] In an embodiment, the filler for electronic materials has a substrate made of strontium titanate or calcium titanate powder as the main component, and a coating is formed on the surface of the substrate by adding a coupling agent. The filler for electronic materials is primarily used as an additive to electronic component encapsulants, substrate materials, heat transfer materials, and the like. It is also preferably used as a resin composition for electronic materials, as described below. The substrate contains strontium titanate or calcium titanate as the main component, and the proportion of the main component in the entire substrate is 95% by mass or more, preferably 97% by mass or more. Components other than the main component are secondary components. Examples of secondary components include SrO, CaO, BaO, Na2O, SiO2, Al3O3, Fe2O3, BaTiO3, TiO2, SrCO3, and CaCO3.

[0028] To form the filler, the substrate is powdery or particulate. It may also be in the form of a plate, flake, whisker, rod, filament, or the like. Titanates are generally known as compounds with high dielectric constants, with barium titanate being particularly widely used. However, in the case of barium titanate, the dielectric constant increases due to the large atomic radius of barium, and the dielectric loss tangent also increases. Therefore, barium titanate is not necessarily a good example, given the purpose of the invention, which is to suppress the dielectric loss tangent. Therefore, strontium titanate or calcium titanate are good examples, since the dielectric loss tangent can be easily controlled, even if the dielectric constant decreases slightly.

[0029] The average volume particle size of the base material is in the range of 0.1 to 3 μm. The particle size is the median diameter (D 50 ) means that the average volume particle diameter of the base material is less than 0.1 μm, the viscosity increases when the filler is added to the resin and kneaded, as described below. This reduces the efficiency of the application process and other processes. If the average volume particle diameter of the base material is more than 3 μm, the particle diameter of the filler itself is large, and segregation occurs due to filler settling in the resin. Therefore, the average volume particle diameter of the base material is preferably in the range of 0.1 to 3 μm, more preferably 0.2 to 2.5 μm, and even more preferably 0.3 to 2.0 μm.

[0030] The surface of the substrate has a coating formed by a coupling agent. That is, the coating is formed by a coupling agent on the surface of the strontium titanate or calcium titanate powder. This structure achieves a high dielectric constant due to the compound in the substrate and a reduced dielectric loss tangent due to the compound in the coating.

[0031] The coupling agent is mainly selected from silane-based coupling agents, titanium-based coupling agents, and aluminate-based coupling agents. These coupling agents may be used alone or in combination. Silane-based coupling agents are compounds in which a silicon atom is bonded to a hydrocarbon group. The examples below use a methoxysilane-based silane-based coupling agent. Titanium-based coupling agents are compounds in which a hydrocarbon group or the like is bonded around a titanium atom. Aluminate-based coupling agents are compounds in which a hydrocarbon group or the like is bonded around an aluminum atom.

[0032] The coupling agent prevents the strontium titanate or calcium titanate in the substrate from being exposed. The surface of the substrate is protected by the coating of the coupling agent. This prevents the compounds in the substrate from reacting with the surroundings and decomposing or changing. In addition, due to the influence of the hydrocarbon groups of the coupling agent, it is easily dispersed when added to resins or the like and kneaded.

[0033] In addition, a silicon compound is added together with the coupling agent. Examples of silicon compounds include silicon oxide and other compounds in which a hydrocarbon group, a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, an aminophenyl group, a ureido group, a mercapto group, an isocyanate group, an acrylic group, or the like is bonded to silicon. The addition of a silicon compound together with a coupling agent strengthens the bonds between the coupling agents in the coating, which is advantageous for improving the physical properties in the examples described below. Furthermore, the ends of the three or more hydrocarbon groups bonded to the silicon may contain compounds having the aforementioned functional groups. Surface treatment with a silicon compound having a functional group at the end of the hydrocarbon group bonded to the silicon increases hydrophobicity, further suppresses moisture adsorption, and further reduces the dielectric tangent.

[0034] The filler for electronic materials, which is formed from a substrate and a coating covering the surface thereof, has the property of a dielectric loss tangent of 0.04 or less at 1 GHz in accordance with JIS C 2138 (2007). In a material formed from a substrate of strontium titanate or calcium titanate and a coating of a silane-based coupling agent or a titanium-based coupling agent, the specific specification of the dielectric loss tangent is a new requirement that has not been reported before.

[0035] The dielectric dissipation factor of fillers for electronic materials is preferably 0.04 or less, and more preferably 0.02 or less. A reduced dielectric dissipation factor reduces the loss that occurs when electromagnetic waves propagate through a dielectric, avoiding energy loss. Therefore, it is desirable for the dielectric dissipation factor to be as small as possible. However, due to the influence of the dielectric constant of the substrate, the value cannot be "0." Furthermore, reducing the dielectric dissipation factor alone is undesirable because it diminishes the favorable dielectric constant of the substrate's dielectric. Therefore, the dielectric dissipation factor is specified as 0.04 or less.

[0036] In the filler for electronic materials according to the embodiment, the surface of the substrate is coated with a coupling agent to form a coating portion. That is, it is necessary for the coupling agents to crosslink with each other and for the coupling agent to bond well with the compound in the substrate. The coating portion formed from the coupling agent is firmly fixed to the substrate, reducing the dielectric loss tangent and is also important from the viewpoint of protecting the substrate.

[0037] To evaluate the degree of adhesion between the substrate and coating, the completed electronic material filler is washed with an organic solvent. After washing, the amount of carbon in the remaining components is measured as the post-wash carbon amount derived from the chemically bonded surface treatment agent. Therefore, by comparing the pre-wash carbon amount (carbon amount) derived from the surface treatment agent of the electronic material filler with the post-wash carbon amount (carbon amount) derived from the chemically bonded surface treatment agent, the amount of coupling agent remaining in the electronic material filler can be determined. As mentioned above, coupling agents contain hydrocarbon groups (methoxy groups) and are highly soluble in organic solvents. However, the titanate in the substrate is hydrophilic and does not dissolve in organic solvents. Therefore, it is easy to dissolve and separate the unreacted coupling agent. The chemically bonded surface treatment agent is the coupling agent that primarily forms the coating.

[0038] Specifically, the carbon content C1 (%) derived from the surface treatment agent before cleaning and the carbon content C2 (%) derived from the chemically bonded surface treatment agent after cleaning are measured, and the C2 / C1 ratio (Rw) is calculated according to the above-mentioned formula (i). The ratio (Rw) is preferably in the range of 0.1 to 1.0. Furthermore, the ratio (Rw) is preferably in the range of 0.2 to 1.0, more preferably in the range of 0.4 to 1.0. A higher ratio (Rw) indicates that the coupling agent is firmly attached to the titanate in the substrate. When the ratio (Rw) of C2 / C1 is below 0.1, this means that 90% of the coupling agent has leaked out and is not useful for forming a coating. When the ratio (Rw) of C2 / C1 is 1, this means that no coupling agent has leaked out.

[0039] The carbon content can be measured by any suitable instrument. In the examples described below, a simultaneous carbon / sulfur analyzer is used. This analyzer is a device that heats and burns carbon and sulfur components and quantitatively analyzes them using infrared light. When cleaning with an organic solvent, 35 g of methyl ethyl ketone is added to 5 g of electronic material filler, the mixture is shaken, and left to stand for 10 minutes. A centrifuge is used for solid-liquid separation, and the sediment is collected and the supernatant is discarded. 35 g of methyl ethyl ketone is added to 5 g of the sediment, the mixture is shaken, and left to stand for 10 minutes. A centrifuge is used for solid-liquid separation, and the sediment is collected and dried. The carbon content of the dried sediment is then measured using a simultaneous carbon / sulfur analyzer or the like.

[0040] Furthermore, in addition to the relative ratio of the remaining coupling agent before and after washing, it is possible to specify the specific amount of remaining coupling agent. That is, the specific surface area Fs( m 2 The amount of carbon after cleaning derived from the chemically bonded surface treatment agent per specific surface area is specified as the chemically bonded amount (reaction amount) of the surface treatment agent calculated from the amount of carbon after cleaning derived from the chemically bonded surface treatment agent per specific surface area. m 2 The amount of carbon after cleaning is the amount of coupling agent that is actually fixed to the substrate.

[0041] Here, the chemical bond amount (reaction amount) of the surface treatment agent calculated from the amount of carbon after cleaning derived from the chemically bonded surface treatment agent per specific surface area is 1 μmol / m 2 If the amount of residual coupling agent is less than 9μmol / s, the required performance of the coated area will not be fully achieved. m 2 If the amount of the coupling agent itself is greater than this, the coating portion becomes resistant, and the dielectric constant of the filler for electronic materials is undesirably lowered.

[0042] The filler for electronic materials according to the embodiment is mainly added to sealing materials for electronic components, substrate materials, heat transfer materials, etc. Therefore, if the viscosity is increased during kneading with the resin to which it is added, the kneading process does not proceed smoothly. In addition, the load when discharging the paste-like kneaded product is large, which causes problems in the coating process. Therefore, it is necessary to prevent the viscosity of the resin after kneading from increasing too much.

[0043] Therefore, the viscosity of electronic material fillers after mixing with liquid epoxy resin must be 500 Pa·s or less. If the viscosity after mixing exceeds 500 Pa·s, the increased viscosity makes it difficult to apply to the target object. Although there is no specific lower limit, if the viscosity is below 100 Pa·s, the product will have excessive fluidity, which can lead to dripping and other problems.

[0044] Specifically, when the base material is strontium titanate, 32.5 g of the filler for electronic materials is mixed and kneaded with 17.5 g of liquid epoxy resin (1.9 to 2.6 Pa s). Alternatively, when the base material is calcium titanate, 29.75 g of the filler for electronic materials is mixed and kneaded with 20.25 g of liquid epoxy resin (1.9 to 2.6 Pa s). Each mixture is then aged at 80°C for 1 hour to prepare a viscosity measurement varnish, and the viscosity of the viscosity measurement varnish at 25°C is measured using an E-type viscometer.

[0045] In the filler for electronic materials according to the embodiment, the strontium titanate and calcium titanate forming the substrate are susceptible to the effects of acids, resulting in the liberation of strontium and calcium. Therefore, a coating is formed on the surface of the substrate to protect the interior, and the coating is made basic. This makes it easier to protect the substrate from the effects of other acids during storage or use of the filler for electronic materials.

[0046] Therefore, the pH of the water extracted from the filler for electronic materials is preferably in the range of 5 to 9.5, more preferably 7 to 9.5. It ranges from weakly acidic to alkaline. To measure the pH of the extracted water, 70 mL of deionized water is added to 3.5 g of the filler for electronic materials, and the mixture is shaken for 30 minutes. The solid-liquid separation is performed using a centrifuge, and the supernatant water is subjected to pH measurement.

[0047] The fillers for electronic materials according to the embodiments described above are added to a resin to prepare a filler-containing resin composition for electronic materials. Examples of resins to which the fillers can be added include thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, other olefin resins, polyimide resins, and liquid crystal polymers, as well as thermosetting resins such as fluororesins, urea resins, and phenolic resins, polyphenylene ethers, and bismaleimides. The fillers can also be added to elastic resins such as styrene-butadiene rubber and isoprene rubber, and silicone resins. For example, epoxy resins are used as resins when producing resin substrates such as substrates for packaging electronic components and interlayer insulating films.

[0048] Examples of epoxy resins used in the resin composition include bisphenol A epoxy resins, bisphenol F epoxy resins, biphenyl epoxy resins, phenol novolac epoxy resins, naphthalene epoxy resins, and phenoxy epoxy resins. The weight of the filler for electronic materials blended into the resin composition is preferably large from the viewpoints of heat resistance and thermal expansion coefficient. It is desirable that the filler for electronic materials be added in an amount of 80% by mass or more relative to the total mass of the resin composition.

[0049] Furthermore, the filler for electronic materials according to the embodiment can be dispersed in a liquid dispersion medium substantially free of water to prepare a slurry for electronic materials. Examples of the dispersion medium include methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, toluene, N-methylpyrrolidone, γ-butyrolactone, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate. The dispersion medium can be used alone or in combination. An appropriate dispersant can also be used.

[0050] Next, a method for producing a filler for electronic materials according to an embodiment will be described. First, strontium titanate or calcium titanate granules are prepared and weighed out in a predetermined amount. A predetermined amount of the silane-based coupling agent or titanium-based coupling agent is then weighed and added to the prepared granules. The two are then thoroughly mixed, and the coupling agent is brought into contact with the surface of the substrate made of strontium titanate or calcium titanate granules (the "contacting step"). The ratio of the coupling agent to the substrate is approximately 0.03 to 3% by weight.

[0051] When the coupling agent comes into contact with the surface of the substrate, reactions such as crosslinking between the coupling agents themselves or bonding between the substrate and the coupling agent are promoted even at room temperature. Thus, a coating derived from the coupling agent is formed on the surface of the substrate. In addition, the substrate that has come into contact with the coupling agent is heated (the "heating step"). The heating step promotes reactions such as crosslinking and bonding of the coupling agent. Here, the heating temperature in the heating step is 200°C or less, preferably 180°C or less. This is because heating above 200°C may cause thermal decomposition of the coupling agent. Furthermore, between the contacting step and the heating step, the aforementioned silicon compound such as silicon oxide is added (the "silicon compound addition step"). The formation of a coating by the silicon compound together with the coupling agent increases the stability of the coating. [Example]

[0052] Fillers for electronic materials were produced as prototypes 1 to 53, and the physical properties of each prototype were evaluated. The raw materials used, production methods, measurement and evaluation methods will be explained below in that order.

[0053] [Raw materials used] The substrates used were strontium titanate (manufactured by Fuji Titanium Industry Co., Ltd., volume average particle size: 1.5 μm), strontium titanate (manufactured by Sakai Chemical Industry Co., Ltd., volume average particle size: 0.3 μm), calcium titanate (manufactured by Fuji Titanium Industry Co., Ltd., volume average particle size: 1.5 μm), and calcium titanate (manufactured by Sakai Chemical Industry Co., Ltd., volume average particle size: 0.3 μm). Also, silicon oxide (manufactured by Admatechs Co., Ltd., silicon oxide: average particle size: 10 nm) was used.

[0054] Of the coupling agents, the following silane-based coupling agents were used: KBM-573 (N-phenyl-3-aminopropylmethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. (referred to as "coupling agent A" in the tables below); KBM-1003 (vinyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. (referred to as "coupling agent B" in the tables below); KBM-1083 (octenyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. (referred to as "coupling agent C" in the tables below); and KBM-3063 (hexyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. (referred to as "coupling agent D" in the tables below). As the titanium-based coupling agent, KR-TTS manufactured by Ajinomoto Fine-Techno Co., Ltd. (referred to as "coupling agent E" in the table below) was used. As the aluminate-based coupling agent, AL-M manufactured by Ajinomoto Fine-Techno Co., Ltd. (referred to as "coupling agent F" in the table below) was used.

[0055] For the capping treatment in the prototype example, SZ-31 (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Co., Ltd. was used. The liquid epoxy resin used in the viscosity measurement was ZX-1059 manufactured by Tohto Kasei Co., Ltd.

[0056] [Preparation of fillers for electronic materials] Prototype example 1 Prototype 1 consisted only of a substrate portion made of strontium titanate (volume average particle size: 1.5 μm).

[0057] Prototypes 2 to 11 Strontium titanate (volume average particle size: 1.5 μm) was used as the base material, and coupling agent A in the table below was added and mixed while varying the weight relative to the weight of the base material.

[0058] Prototype example 12 The same composition as in Prototype Example 9 was used and heated at 180°C for 2 hours.

[0059] Prototypes 13 and 14 In prototype 13, strontium titanate (volume average particle size: 1.5 μm) was used as the base material, and coupling agent B in the table below was added and mixed with the weight of the base material. For Sample 14, Sample 13 was prepared, and then hexamethyldisilazane was added.

[0060] Prototypes 15 to 19 Strontium titanate (volume average particle size: 1.5 μm) was used as the base material, and coupling agent C in the table below was added and mixed while varying the weight relative to the weight of the base material.

[0061] 20 to 25 prototypes Strontium titanate (volume average particle size: 1.5 μm) was used as the base material, and coupling agent C in the table below was added and mixed while changing the weight relative to the weight of the base material. After addition, the mixture was heated at 180°C for 2 hours.

[0062] Prototype Example 26 Sample 26 consisted only of a substrate made of strontium titanate (volume average particle size: 0.3 μm).

[0063] Prototypes 27 to 29 Strontium titanate (volume average particle size: 0.3 μm) was used as the base material, and coupling agent A in the table below was added and mixed while varying the weight relative to the weight of the base material.

[0064] Prototype example 30 Prototype 30 consisted only of a substrate portion made of calcium titanate (volume average particle size: 1.5 μm).

[0065] Prototypes 31 to 36 Calcium titanate (volume average particle size: 1.5 μm) was used as the base material, and coupling agent C in the table below was added and mixed while changing the weight relative to the weight of the base material. After addition, the mixture was heated at 180°C for 2 hours.

[0066] Prototypes 37 to 41 Strontium titanate (volume average particle size: 1.5 μm) was used as the base material, and silicon oxide was added and mixed together with coupling agent A in the table below while changing the weight relative to the weight of the base material.

[0067] Prototypes 42 to 46 Strontium titanate (volume average particle size: 1.5 μm) was used as the base material, and silicon oxide was added and mixed together with coupling agent B in the table below while changing the weight relative to the weight of the base material.

[0068] Prototypes 47 to 50 Strontium titanate (volume average particle size: 1.5 μm) was used as the base material, and silicon oxide was added to the base material along with coupling agent B in the table below while varying the weight of the silicon oxide, and mixed. After addition, the mixture was heated at 180°C for 2 hours.

[0069] Prototypes 51 to 53 Strontium titanate (volume average particle size: 1.5 μm) was used as the base material, and coupling agent C (Prototype 51), coupling agent D (Prototype 52), and coupling agent F (Prototype 53) shown in the table below were added to the base material by weight and mixed. After addition, the mixture was heated at 180°C for 2 hours.

[0070] [Measurement and evaluation methods] ·Dielectric tangent The dielectric loss tangent of each prototype was measured in accordance with JIS C 2138 (2007). Specifically, the relative permittivity and dielectric loss tangent at 1 GHz were measured using a Keysight network analyzer (product name "E5071C") and the cavity resonator perturbation method. This measurement was performed in accordance with ASTM D2520 (JIS C 2565 (1992)).

[0071] Measurement of carbon content (carbon amount) derived from chemically bonded surface treatment agents 5g of each prototype was weighed out and mixed with 35g of methyl ethyl ketone, then shaken using a shaker and allowed to settle for 10 minutes. After solid-liquid separation using a centrifuge, the supernatant was discarded. 5g of the sediment was mixed with 35g of methyl ethyl ketone, then shaken using a shaker and allowed to settle for 10 minutes. After solid-liquid separation using a centrifuge, the supernatant was discarded and the sediment was obtained. The sediment was dried to obtain a sample for carbon content measurement. This sample was washed. Before washing, no methyl ethyl ketone was added and the sample was used for measurement as is.

[0072] The carbon content was measured using a LECO carbon / sulfur simultaneous analyzer (product name "CS-444LS type") and JSS061-8 as the carbon standard sample. The carbon content Rw was calculated from the carbon content before and after cleaning.

[0073] ·BET specific surface area measurement 1.0 g of each prototype was weighed out and placed in a measurement cell. After pretreatment, the BET specific surface area was measured. The measuring machine used was "Macsorb HMmodel-1208" (manufactured by MACSORB). The pretreatment conditions were as follows: Degassing temperature: 200℃ Degassing time: 30 minutes Cooling time: 4 minutes

[0074] ·Viscosity measurement When the base material of the prototype was strontium titanate, 32.5 g of the prototype was mixed with 17.5 g of liquid epoxy resin (1900 to 2600 mPa s) and kneaded.When the base material of the prototype was calcium titanate, 29.75 g of the prototype was mixed with 20.25 g of the liquid epoxy resin.

[0075] The kneaded mixtures were each aged at 80°C for 1 hour to prepare varnishes for viscosity measurement, and the viscosities of the varnishes for viscosity measurement at 25°C were measured using an E-type viscometer.

[0076] ·pH measurement 3.5 g of each sample was weighed and placed in a plastic container, 70 ml of deionized water was poured into it, and the container was shaken for 30 minutes using a shaker. After solid-liquid separation using a centrifuge, the supernatant water was collected and the pH was measured.

[0077] ·comprehensive evaluation The overall evaluation of the prototypes was based on the results of each measurement item and was divided into four levels: "A" for the best, followed by "B," "C," and "D." Evaluation "A": The dielectric loss tangent is 0.02 or less. The specific Rw is 0.4 to 1.0. The chemical bond amount (reaction amount) of the surface treatment agent calculated from the amount of carbon after cleaning derived from the chemically bonded surface treatment agent per specific surface area is 2.0 μmol / m 2 The viscosity is 500 Pa·s or less. The pH of the extracted water is 9.5 or less. Evaluation "B": The dielectric loss tangent is 0.04 or less. The ratio Rw is 0.2 to 1.0. The chemical bond amount (reaction amount) of the surface treatment agent calculated from the amount of carbon after cleaning derived from the chemically bonded surface treatment agent per specific surface area is 2.0 μmol / m 2 The viscosity is 500 Pa·s or less. The pH of the extracted water is 9.5 or less. Evaluation "C": The dielectric loss tangent is 0.02 or less. The ratio Rw is 0.1 to 1.0. The chemical bond amount (reaction amount) of the surface treatment agent calculated from the amount of carbon after cleaning derived from the chemically bonded surface treatment agent per specific surface area is 2.0 μmol / m 2 The viscosity is 500 Pa·s or less. The pH of the extracted water is 9.5 or less. Rating "D": A prototype that does not fall under ratings A, B, or C.

[0078] The prototypes rated "A" showed the best results and are most preferable as fillers for electronic materials. The prototypes rated "B" showed good results and are preferable as fillers for electronic materials, next to those rated "A." The prototypes rated "C" are examples that can be used as fillers for electronic materials. Samples rated "D" are not suitable as fillers for electronic materials.

[0079] [result] Tables 1 to 5 show the individual raw materials and compositions, as well as the measurement results and overall evaluation for Prototypes 1 to 53. Also shown are photographs taken with a scanning electron microscope (SEM). Figure 1 is a 20,000x magnified photograph of Prototype 6. Figure 2 is a 20,000x magnified photograph of Prototype 1.

[0080] [Table 1]

[0081] [Table 2]

[0082] [Table 3]

[0083] [Table 4]

[0084] [Table 5]

[0085] [Table 6]

[0086] [Consideration] By comparing the photographs in Figures 1 and 2, it was possible to confirm the formation of a coating by the coupling agent.

[0087] Prototypes 1, 26, and 30 are examples that do not contain a coupling agent. This is undesirable as it increases viscosity and worsens pH properties. Therefore, it can be said that a coupling agent is essential. While heating is optional, it is preferable to apply heat, as in Prototypes 12, 20 to 25, and 31 to 36, because it is believed that this promotes a reaction on the surface of the substrate. While incorporating a silicon compound into the coating is optional, it is preferable to incorporate a silicon compound, as in Prototypes 37 to 50, because this enhances the protective effect of the coating.

[0088] Prototypes 2 to 12 are examples in which the amount of coupling agent was changed. Prototypes 2, 3, and 4, which contain small amounts of coupling agent, show increased viscosity. Also, in 8 to 11, which contain large amounts of coupling agent, the dielectric loss tangent deteriorates. A comparison of prototypes 9 and 12 shows that heat treatment improves the properties. A comparison of prototypes 13 and 14 confirms that capping treatment reduces the dielectric loss tangent.

[0089] Prototypes 15 to 25 are examples in which the type of coupling agent was changed, and the relationship between the amount of addition showed the same tendency as in prototypes 2 to 12. In addition, an improvement was also confirmed in the ratio of the amount of carbon (carbon amount) derived from the chemically bonded surface treatment agent before and after cleaning by heat treatment.

[0090] Prototypes 27 to 29 are examples in which the particle size of the substrate was changed to a smaller size. Good results were also obtained with these particle sizes.

[0091] In prototypes 31 to 36, the substrate was changed to calcium titanate, and the relationship of the added amount showed the same tendency as in prototypes 2 to 12. In addition, an improvement was confirmed in the ratio of the amount of carbon (carbon amount) derived from the chemically bonded surface treatment agent before and after cleaning by heat treatment.

[0092] Samples 37 to 50 contain silicon oxide as a silicon compound in the coating. Good properties were confirmed in the ratio of the carbon amount (carbon content) derived from the chemically bonded surface treatment agent, the dielectric tangent, and the viscosity before and after cleaning.

[0093] Prototypes 51 to 53 are examples in which the type of coupling agent was changed. As in these prototypes, even when a long-chain silane-based coupling agent and an aluminate-based coupling agent were used, good properties were confirmed in the ratio of the carbon amount (carbon amount) derived from the chemically bonded surface treatment agent before and after cleaning, and in the dielectric tangent.

Claims

1. a substrate portion containing strontium titanate or calcium titanate as a main component; a coating portion formed on a surface of the base material by a coupling agent that is a silane-based coupling agent or an aluminate-based coupling agent, In the filler for electronic materials, in the following measurement (I) of the amount of carbon derived from a chemically bonded surface treatment agent after cleaning, the ratio (Rw) of the amount of carbon derived from a chemically bonded surface treatment agent after cleaning (C2(%)) / the amount of carbon derived from a surface treatment agent before cleaning (C1(%)) represented by formula (i) satisfies the range of 0.2 to 1.0, the filler for electronic materials has a dielectric loss tangent at 1 GHz in accordance with JIS C 2138 (2007) of 0.02 or less; the chemically bonded amount (reaction amount) of the surface treatment agent calculated from the amount of carbon after cleaning derived from the chemically bonded surface treatment agent per specific surface area (Fs (m 2 )) of the filler for electronic materials measured by the BET method satisfies the range of 1 to 9 μmol / m 2 , The pH of the water extracted with the filler for electronic materials is in the range of 5 to 9.

5. A filler for electronic materials characterized by: [Equation 1] Measurement of post-wash carbon amount derived from chemically bonded surface treatment agent (I): 35 g of methyl ethyl ketone is added to 5 g of the filler for electronic materials, the mixture is shaken and left to stand for 10 minutes, and a sediment is obtained by solid-liquid separation using a centrifuge. The supernatant is discarded, and 35 g of methyl ethyl ketone is added to 5 g of the sediment, the mixture is shaken and left to stand for 10 minutes, and a sediment is obtained by solid-liquid separation using a centrifuge. The sediment is then dried. The carbon amount in the dried sediment is measured as the post-wash carbon amount derived from the chemically bonded surface treatment agent. The pH of the water extracted with the filler for electronic materials is the pH of the supernatant water obtained by adding 70 mL of deionized water to 3.5 g of the filler for electronic materials, shaking the mixture for 30 minutes, and separating the solid and liquid using a centrifuge.

2. 2. The filler for electronic materials according to claim 1, wherein the volume average particle diameter of the base material falls within the range of 0.1 to 3 μm.

3. 3. The filler for electronic materials according to claim 1, wherein the filler for electronic materials has a viscosity of 500 Pa·s or less after being kneaded with a liquid epoxy resin in the following viscosity measurement (II). Viscosity measurement (II): When the main component of the substrate is strontium titanate, 32.5 g of the filler for electronic materials is mixed and kneaded with 17.5 g of a liquid epoxy resin (1900 to 2600 mPa s), or when the main component of the substrate is calcium titanate, 29.75 g of the filler for electronic materials is mixed and kneaded with 20.25 g of a liquid epoxy resin (1900 to 2600 mPa s), and each is aged at 80°C for 1 hour to prepare a varnish for viscosity measurement, and the viscosity of the varnish for viscosity measurement at 25°C is measured using an E-type viscometer.

4. 4. The filler for electronic materials according to claim 1, wherein the coating portion contains silicon oxide as a silicon compound different from the silane coupling agent.

5. A method for producing the filler for electronic materials according to any one of claims 1 to 4, comprising: a contacting step of contacting a coupling agent with the surface of the substrate mainly composed of strontium titanate or calcium titanate; a heating step of heating the substrate portion in contact with the coupling agent. A method for producing a filler for electronic materials, comprising:

6. 6. The method for producing a filler for electronic materials according to claim 5, wherein the coupling agent is a silane-based coupling agent or a titanium-based coupling agent.

7. 7. The method for producing a filler for electronic materials according to claim 5, wherein the heating step is performed at 200°C or less.

8. Between the contacting step and the heating step, The method for producing a filler for electronic materials according to claim 5 , further comprising a silicon compound adding step of adding silicon oxide as a silicon compound different from the silane coupling agent.

9. A filler-containing resin composition for electronic materials, comprising a resin containing the filler for electronic materials according to any one of claims 1 to 4.

10. The filler for electronic materials according to any one of claims 1 to 4, a liquid dispersion medium in which the filler for electronic materials is dispersed and which does not substantially contain water; A slurry for electronic materials, comprising:

Images