Spherical calcium titanate powder and resin composition

Abstract

Provided are: a spherical calcium titanate powder which has excellent resin filling properties, has a higher relative dielectric constant, has little increase in the dielectric loss tangent over time, and is capable of maintaining a low dielectric loss tangent for a long period of time; and a resin composition containing the same. The spherical calcium titanate powder according to the present invention has a ratio ((b) / (a)) of 1.02-1.26, said ratio being between the peak intensity (b) at a wavenumber of 3505 cm-1 and the average value (a) of the peak intensity at a wavenumber of 3495 cm-1 and the peak intensity at a wavenumber of 3515 cm-1, said peak intensity (b) at a wavenumber of 3505 cm-1 being measured by diffuse reflection Fourier transform infrared spectroscopy (FT-IR).

Description

Technical Field

[0001] This disclosure relates to spherical calcium titanate powder and resin compositions. Background Technology

[0002] In recent years, with the increase in information communication volume in the communications field, high-frequency signals are being widely used in electronic and communication equipment. On the other hand, applying high-frequency signals to these devices can also lead to problems such as increased transmission loss of circuit signals.

[0003] Furthermore, with the increasing functionality of related electronic materials and components, there is a demand for further miniaturization of electronic and communication equipment. For communication equipment, increasing the relative permittivity of the antenna material assembled within it allows for further miniaturization. Therefore, a material (ceramic filler) capable of achieving both high relative permittivity and low dielectric loss tangent is required.

[0004] In response to relevant requirements, perovskite-type composite oxides, primarily represented by ABO3 and represented by barium titanate and strontium titanate, are expected to serve as ceramic fillers for next-generation electronic devices due to their high relative permittivity. Among these, titanium-based composite oxides are being used as electronic materials due to their excellent electrical properties, including dielectric, pyroelectric, and piezoelectric properties. Patent Document 1 describes calcium titanate powder with high crystallinity and excellent electrical properties, as well as a method for its manufacture.

[0005] Ceramic fillers are mostly used in resins. Therefore, from the perspective of improving resin filling and dispersibility, thereby stabilizing dielectric properties, and also from the perspective of improving processability and workability, it is desirable for their shape to be closer to a sphere. Patent Document 1 describes calcium titanate powder with particles in the shape of cubic prisms or similar cubic prisms, and does not study powders containing spherical calcium titanate particles.

[0006] In addition, ceramic fillers suffer from a problem of the dielectric loss tangent increasing over time. Therefore, there is a need for a ceramic filler with a smaller increase in the dielectric loss tangent over time and capable of maintaining a low dielectric loss tangent for a longer period than before.

[0007] Existing technical documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2011-116645

[0009] Patent Document 2: Japanese Patent No. 4155750

[0010] Patent Document 3: Japanese Patent Application Publication No. 2012-246203 Summary of the Invention

[0011] The subject of this disclosure is to provide spherical calcium titanate powder and a resin composition comprising the spherical calcium titanate powder, wherein the spherical calcium titanate powder has excellent resin filling properties, a higher relative permittivity, and a smaller time-dependent increase in dielectric loss tangent, and can maintain a low dielectric loss tangent for a long period of time.

[0012] After in-depth research, the inventors surprisingly discovered that as long as the wavenumber of spherical calcium titanate powder measured in diffuse reflectance Fourier transform infrared spectroscopy (FT-IR) is 3505 cm⁻¹, the desired result is achieved. -1 Peak intensity (b) relative to wavenumber 3495 cm⁻¹ -1 Peak intensity and wavenumber 3515cm -1 The ratio of the average peak intensity (a) to (b) (a) is 1.02 to 1.26, which indicates a higher relative permittivity and a smaller increase in dielectric loss tangent over time, allowing it to maintain a low dielectric loss tangent for a long time. In addition, it also has good resin filling properties.

[0013] According to this disclosure, spherical calcium titanate powder and a resin composition comprising the spherical calcium titanate powder are provided, wherein the spherical calcium titanate powder has excellent resin filling properties, a higher relative permittivity, and a smaller time-dependent increase in dielectric loss tangent, and can maintain a low dielectric loss tangent for a long period of time. Attached Figure Description

[0014] Figure 1 This is an example of a graph showing the results of FT-IR analysis of spherical calcium titanate powders from Comparative Examples 1-2 and Examples 1-3.

[0015] Figure 2 This is an example of a graph showing the results of FT-IR analysis of spherical calcium titanate powders from Comparative Examples 1-2 and Examples 1-3. Detailed Implementation

[0016] The following is a detailed description of one embodiment of this disclosure; however, the scope of this disclosure is not limited to the single embodiment described herein, and various modifications can be made without departing from the spirit of this disclosure. The various methods disclosed in this specification can be combined with any other features disclosed in this specification. Furthermore, for a specific parameter, when multiple upper and lower limits are provided, any combination of these upper and lower limits can be used to form a preferred numerical range. Additionally, the lower and / or upper limits of the numerical range described in this disclosure are values ​​within that range, and can also be replaced with the values ​​shown in the embodiments. The expression "X to Y" representing a numerical range means "above X and below Y". In other embodiments, there may be instances where a specific description described for one embodiment is also applicable to other embodiments.

[0017] Each component in each embodiment and combinations thereof are merely examples, and within the scope not departing from the gist of the present disclosure, additions, omissions, substitutions, and other modifications of the components can be appropriately made. The present disclosure is not limited by the embodiments.

[0018] All manners disclosed in this specification can be combined with any other features disclosed in this specification.

[0019] In this specification, "powder" refers to an aggregate of multiple particles.

[0020] [Calcium titanate spherical powder]

[0021] The calcium titanate spherical powder related to this embodiment (hereinafter, there are also cases where it is separately referred to as "powder") is characterized in that the peak intensity (b) at a wave number of 3505 cm measured by diffuse reflectance FT-IR method -1 relative to the average value (a) of the peak intensity at a wave number of 3495 cm -1 and the peak intensity at a wave number of 3515 cm -1 is 1.02 to 1.26 for the ratio ((b) / (a)).

[0022] Since the peak intensity (b) at a wave number of 3505 cm measured by diffuse reflectance FT-IR method -1 relative to the average value (a) of the peak intensity at a wave number of 3495 cm -1 and the peak intensity at a wave number of 3515 cm -1 is 1.02 to 1.26 for the ratio ((b) / (a)) (hereinafter, there are also cases where it is separately referred to as "(b) / (a)"), the dielectric loss tangent of the powder is difficult to increase with time, and thus a low dielectric loss tangent can be maintained for a long time. Such a powder can also be stored for a longer time than in the past. In addition, since the powder related to this embodiment is spherical, the filling property for the resin is also good. Further, the powder related to this embodiment can also achieve a higher relative dielectric constant.

[0023] "Spherical powder" in the present disclosure means that when observing the powder at a magnification of 10,000 times using a scanning electron microscope, the shape of each particle is observed to be circular or round granular. Since the powder related to this embodiment is a calcium titanate powder containing spherical particles, the filling property for the resin is also good.

[0024] <FT-IR analysis>

[0025] The diffuse reflectance FT-IR analysis of the powder related to this embodiment can be performed according to the following conditions.

[0026] First, spherical calcium titanate powder is filled into the sample tray until it is full. Then, using a Fourier transform infrared spectrophotometer (e.g., a PerkinElmer Frontier infrared spectrometer, product name "SpectrumOne"), measurements are taken under atmospheric conditions using the diffuse reflectance method (resolution 4.0 cm⁻¹). -1 (Accumulated count: 64). Normalization was performed at the wavenumber where reflectance was minimized, followed by KM transform. The resulting diffuse reflectance spectrum was calculated based on a wavenumber of 3495 cm⁻¹. -1 Peak intensity and wavenumber 3515 cm⁻¹ -1 The peak intensity was calculated, and the average value (a) was calculated. Next, the wavenumber 3505 cm⁻¹ was determined. -1 The ratio of the peak intensity (b) to the average value (a) above ((b) / (a)).

[0027] The powder described in this embodiment, in the diffuse reflectance FT-IR method, at a wavenumber of 3500 cm⁻¹ -1 An absorption peak is present nearby. The ratio of the peak intensity of the absorption peak of the powder related to this embodiment (peak intensity (b) above) to the average value of the peak intensities surrounding the absorption peak (average value (a) above) is 1.02 to 1.26. In one embodiment, the lower limit of (b) / (a) may exceed 1.02, or be 1.04 or more, or 1.06 or more. In one embodiment, the upper limit of (b) / (a) may be 1.25 or less, or 1.24 or less, or 1.20 or less, or 1.14 or less. In a preferred embodiment, (b) / (a) exceeds 1.02 and is less than 1.26, and may be 1.04 to 1.23.

[0028] Wave number estimated at 3500 cm⁻¹ -1 The nearby peaks are derived from chemically adsorbed water (OH functional groups on the surface) from the powder. On the other hand, peaks from physically adsorbed water (OH functional groups) from the powder were observed at a wavenumber of 3400 cm⁻¹. -1 A wider peak with a summit nearby.

[0029] Typical calcium titanate powder, such as that shown in Reference Example 2, has a (b) / (a) ratio of less than 1.02. That is, in typical calcium titanate powder, the wavenumber is 3505 cm⁻¹. -1 The peak intensity (b) differs little from the average intensity of its surrounding peaks (a), and is not observed as a significant peak. This is thought to be due to the hydrogen bonds formed between the OH functional groups on the surface of typical calcium titanate powder and physically adsorbed water, thus facilitating the adhesion of physically adsorbed water. The resulting wavenumber is 3505 cm⁻¹. -1 The peak is completely submerged by the broader peak (wavenumber 3400 cm⁻¹) originating from physically adsorbed water. -1Among the wider peaks nearby, it is speculated that the difference between its average intensity and that of the surrounding peaks (a) is small ((b) / (a) is less than 1.02).

[0030] When calcium titanate powder is spheroidized at high temperature, for example, Comparative Example 1 and Figure 1 As shown, the wave number is 3505 cm⁻¹. -1 The peak intensity (b) is significantly higher than the average peak intensity (a) of the surrounding wavenumbers, with (b) / (a) exceeding 1.26. On the other hand, the wavenumber of the powder related to this embodiment is 3505 cm⁻¹. -1 The peak intensity (b) is slightly higher than the average peak intensity (a) of the surrounding wavenumbers. When the inventors of this application carefully investigated the relationship between the ratio (b) of the peak intensity of the OH functional groups originating from the surface and the average peak intensity (a) of the surrounding wavenumbers (b / a) and dielectric properties, they were surprised to find that spherical calcium titanate powder with a (b) / (a) ratio of 1.02 to 1.26 has a relatively higher dielectric constant than conventional calcium titanate powders. Furthermore, the temporal increase in the dielectric loss tangent is also smaller. This is presumably because powders with a (b) / (a) ratio in the above range not only have a lower absolute number of OH functional groups on their surface, but also have less difficulty in adsorbing physically adsorbed water. In addition, "spherical calcium titanate powder with a (b) / (a) ratio of 1.02 to 1.26" can be easily achieved, for example, by further heat-treating the sphericalized calcium titanate powder at a specific temperature (preferably 600 to 1000°C).

[0031] In one embodiment, the diffuse reflectance FT-IR of the powder, measured at a wavenumber of 870 cm⁻¹, is present. -1 Up to wave number 890cm -1 The peak intensity (c) of the absorption peak (C) is relative to the peak intensity at wavenumber 640 cm⁻¹. -1 Up to wave number 670cm -1 The ratio of the peak intensity (d) of the absorption peak (D) to the peak intensity (d) (hereinafter referred to as "(c) / (d)") can be 5.0 or higher, 7.0 or higher, 7.5 or higher, or 8.0 or higher. Powders with a (c) / (d) ratio of 5.0 or higher tend to have a higher relative permittivity, and the time-dependent increase in the dielectric loss tangent is also more easily reduced.

[0032] The upper limit of (c) / (d) is not particularly limited as long as the effects of the present invention are achieved. In one embodiment, it can be 14.0 or less, 13.0 or less, 12.0 or less, or 11.5 or less. That is, (c) / (d) can be 5.0 to 14.0, or 6.0 to 13.0. (c) / (d) can be determined by the same method as the FT-IR analysis described above. Additionally, "present at wavenumber 640 cm⁻¹" -1 Up to wave number 670cm -1 The absorption peak (D) is the absorption peak with the highest intensity within this wavenumber range. Similarly, the absorption peak present at wavenumber 870 cm⁻¹ is the absorption peak with the highest intensity within this wavenumber range. -1 Up to wave number 890cm -1 The absorption peak (C) is also the absorption peak with the highest peak intensity in this wavenumber range.

[0033] <Average particle size (D50)>

[0034] The average particle size (D50) of the spherical calcium titanate powder according to this embodiment (hereinafter, it may also be referred to as "D50") is preferably 0.5 to 15 μm. The D50 of the powder according to this embodiment can be measured under the following conditions.

[0035] (Conditions for determining average particle size)

[0036] The average particle size was measured using a laser diffraction / scattering particle size distribution measuring device (e.g., the product name "MT 3300 EXII" manufactured by MicrotracBEL Co., Ltd.).

[0037] First, fill an 80cm glass beaker with water. 3 0.1 g of spherical calcium titanate powder was dispersed in pure water for 1 minute using an ultrasonic homogenizer (e.g., the trade name "UH-600S" manufactured by SMT Co., Ltd., with a homogenizer tip diameter of 20 mm φ). The dispersion of the spherical calcium titanate powder was added dropwise to a laser diffraction / scattering particle size distribution measuring device using a dropper. The average particle size was measured 30 seconds after the start of the specified addition. The particle size distribution was calculated based on the intensity distribution of diffracted / scattered light from the spherical calcium titanate powder detected by the sensor in the laser diffraction / scattering particle size distribution measuring device. The D50 was calculated based on the cumulative particle size distribution corresponding to 50% of the particle size in the volumetric reference of the measured particle size.

[0038] In one embodiment, from the viewpoint of easily forming powders with a small time-dependent rise in dielectric loss tangent and a relatively high dielectric constant, the D50 of the powder can be 1μm to 15μm, or 2μm to 15μm, or 3μm to 15μm, or 4μm to 15μm, or 4μm to 10μm, or 4μm to 9μm, or 5μm to 10μm, or 5μm to 9μm.

[0039] Specific surface area (BET)

[0040] The specific surface area (BET) of the spherical calcium titanate powder in this embodiment is preferably 1.0 m². 2 / g or less. The specific surface area of ​​the powder can be determined using the BET multi-point method with a fully automated specific surface area measuring device. Specifically, the determination can be performed under the following conditions.

[0041] (Methods for determining specific surface area)

[0042] The specific surface area (BET) of spherical calcium titanate powder was determined by the following method.

[0043] First, 4g of spherical calcium titanate powder was filled into an empty tank and degassed at 300°C. After degassed, the tank filled with the spherical calcium titanate powder was placed in a fully automated specific surface area measuring device (e.g., the "Macsorb Model 1208" manufactured by Mountech) for specific surface area measurement. A He-N2 mixed gas was used for measurement, and the measurement was performed at a main flow rate of 25mL / min using a multi-point method.

[0044] In one embodiment, the specific surface area (BET) of the powder can be 0.9 m². 2 Below / g, it can also be 0.8m 2 Below / g, it can also be 0.7m 2 / g or less. Furthermore, the lower limit is preferably 0.5m. 2 / g or more. That is, the specific surface area (BET) of the powder can be 0.5~1.0m². 2 / g, or 0.5~0.9m 2 / g, and can also be 0.5~0.8m 2 / g, and can also be 0.5~0.7m 2 / g.

[0045] Mean sphericity

[0046] The average sphericity of the spherical calcium titanate powder in this embodiment is preferably 0.80 or higher. As long as the average sphericity is 0.80 or higher, it is easier to further improve the filling and dispersibility of the resin. The average sphericity of the spherical calcium titanate powder can be 0.85 or higher, 0.86 or higher, or 0.87 or higher. Furthermore, the average sphericity of the spherical calcium titanate powder can be measured by the following method.

[0047] (Method for determining mean sphericity)

[0048] The determination is performed using a powder imaging analyzer (e.g., the Spectris "FPIA-3000"), following these steps.

[0049] The sample was dispersed in pure water to obtain the test sample. The test sample was then flowed in the planar extension flow tank of the above-described apparatus, and an image of more than 200 spherical calcium titanate particles moving in the tank was recorded using an objective lens. The average sphericity was calculated from the recorded image and the following formula (1).

[0050] Mean sphericity = (π × HD / PM) 2 …(1)

[0051] In equation (1), HD represents the equivalent circle diameter of the particle, which is obtained by the ratio of the projected area of ​​the object particle to the area of ​​the circle. PM represents the projected circumference of the object particle. For the average sphericity, the "average sphericity" can be calculated first based on the average sphericity (π×HD / PM) of 200 spherical calcium titanate particles, and then the average sphericity can be squared to obtain the mean sphericity.

[0052] <Moisture content>

[0053] In one embodiment, after drying 50g of powder at 100°C for 6 hours, the adsorbed moisture content of the powder, measured using the Karl Fischer method at a maintained temperature of 200°C, is preferably 400 ppm or less. Since the powder in this embodiment is unlikely to adhere to physically adsorbed water, the adsorbed moisture content is easily below 400 ppm. This is preferable because the time-dependent increase in the dielectric loss tangent of such powder is smaller. Furthermore, the relative permittivity is also more likely to increase further. Based on the smaller time-dependent increase in the dielectric loss tangent and the easier reduction of the initial value of the dielectric loss tangent, the adsorbed moisture content is further preferably 350 ppm or less, and particularly preferably 300 ppm or less. The adsorbed moisture content of the powder can be specifically measured under the following conditions.

[0054] (Method for determining adsorbed moisture content)

[0055] 50g of powder was placed in an aluminum cup and dried at 100°C for 6 hours. Subsequently, 3g of the dried powder was added to a Karl Fischer moisture meter (e.g., product name "CA-310" manufactured by Nitto Seiko Analytech Co., Ltd.), heated to 200°C, and the amount of released water (ppm by mass) was measured. The measurement was performed under an argon atmosphere. Measurements were continued until the background value was below 0.2 μg / s.

[0056] The calcium titanate constituting the spherical calcium titanate powder of this embodiment is a composite oxide having a perovskite-type crystal structure represented by the general formula ABO3, specifically CaTiO3 in which Ca occupies A and Ti occupies B. The crystal structure of the spherical calcium titanate powder can be determined by X-ray diffraction.

[0057] In one embodiment, the spherical calcium titanate powder can be surface-treated using a surface treatment agent. By surface-treating with a surface treatment agent, the filling properties of the spherical calcium titanate powder into the resin are easily improved. Examples of surface treatment agents include silane coupling agents and aluminate coupling agents. One or more of these can be used alone or in combination. From the viewpoint of easily reducing polar functional groups on the particle surface, treatment with a silane coupling agent is preferred, and treatment with a vinyl group-containing silane coupling agent such as hexamethyldisilazane (HMDS) or vinyltrimethoxysilane is more preferred.

[0058] In one embodiment, by treating the powder with a surface treatment agent containing hydrophobic functional groups, such as vinylsilane or hexamethyldisilazane (HMDS), it is easy to reduce the polar functional groups (including OH functional groups) on the surface of the particles constituting the spherical calcium titanate powder, thereby easily suppressing the adhesion of physically adsorbed water. Therefore, (b) / (a) is easily 1.02 to 1.26. As a result, the time-dependent increase in the dielectric loss tangent is easily reduced. Furthermore, the presence or absence of surface treatment of the spherical calcium titanate powder can be confirmed by analyzing the powder using methods such as IR, TG-DTA, or mass spectrometry.

[0059] The spherical calcium titanate powder of this embodiment may also contain other components besides calcium titanate. Examples of other components include calcium carbonate and titanium oxide. These other components may be contained individually or in combination with two or more. When the spherical calcium titanate powder of this embodiment contains other components, their content relative to the total mass of the spherical calcium titanate powder is preferably 1% by mass or less, more preferably 0.5% by mass or less. From the viewpoint of easily achieving a low dielectric loss tangent, the spherical calcium titanate powder preferably does not contain other components.

[0060] In one embodiment, the dielectric loss tangent of the powder stored in a desiccant at 25°C / 35%RH for 2 weeks, as determined later, is preferably 8.0 × 10⁻⁶. -3 The following is more preferably 6.0×10 -3 The following is a summary of the following. Since the dielectric loss tangent of the powder related to this embodiment increases less over time, a low dielectric loss tangent can be maintained even after the powder related to this embodiment has been stored in the dryer for more than 2 weeks, for example.

[0061] In one embodiment, the relative permittivity of the spherical calcium titanate powder of this embodiment, measured under the conditions described later, is preferably 50 or more at 1 GHz, more preferably 60 or more. Furthermore, the aforementioned relative permittivity may be 70 or more, or 85 or more.

[0062] [Method for manufacturing spherical calcium titanate powder]

[0063] The spherical calcium titanate powder of this embodiment can be manufactured by, for example, a method including spheroidizing raw calcium titanate powder (step (i)) and heating the spheroidized calcium titanate powder at 600 to 1200°C (step (ii)). Hereinafter, one embodiment of the method for manufacturing spherical calcium titanate powder including steps (i) to (ii) will be described.

[0064] <Process (i)>

[0065] In the manufacturing method of this embodiment, step (i) is a step of spheroidizing the raw material calcium titanate powder. By including step (i), a powder with excellent resin filling properties can be easily obtained. Step (i) is preferably performed by spheroidizing the raw material calcium titanate powder using a powder melting method.

[0066] As for the raw material calcium titanate powder (hereinafter referred to separately as "raw material powder"), from the viewpoint of the average particle size of the spheroidized powder, the ease of processing the powder, or the ease of feeding, the average particle size (D50) is preferably 0.2 to 30 μm, more preferably 1 to 20 μm. In addition, the average sphericity of the raw material powder is not particularly limited.

[0067] There are no particular limitations on the preparation method of the raw material powder. For example, bulk powder of calcium titanate obtained by reacting titanium oxide (TiO2) with calcium carbonate (CaCO3) under high temperature conditions can be used as the raw material powder, or calcium titanate powder prepared by a wet method can be used as the raw material powder. From the viewpoint of ease of acquisition and economy, it is preferable to use the powder prepared by the solid-state method as the raw material powder.

[0068] From the perspective of reducing the dielectric loss tangent and improving the reliability of electronic materials, the preferred raw material powder contains alkali metal elements such as Li, Na, and K, and impurities such as metallic elements such as Fe, as well as Cl. - ,Br - The content of anions is relatively low. Specifically, it is preferred that the combined amount of these impurities and anions in the raw material powder is less than 0.01% by mass.

[0069] As described above, the preferred step (i) is the step of spheroidizing the raw material powder by a powder melting method. The powder melting method refers to a method of spheroidizing the raw material powder by introducing it into a high-temperature condition above its melting point, such as a flame, plasma, electric furnace, or gas furnace. For example, the methods described in Patent Documents 2 and 3 can be used. The melting atmosphere is not particularly limited; from the viewpoint of easily preventing the reduction of the raw material powder, it is desirable to perform spheroidizing in an environment with a high oxygen partial pressure, for example, spheroidizing can be performed in a flame using LPG / O2 gas. Furthermore, the method of feeding the raw material powder is not particularly limited; it can be supplied as dry powder or as a slurry in which the powder is dispersed in water, alcohol, etc.

[0070] In one embodiment, step (i) may also be performed by spherizing the raw material powder to prepare spherical calcium titanate powder with an average sphericity of 0.80 or higher.

[0071] <Process (ii)>

[0072] The manufacturing method described in this embodiment includes heating the spheroidized calcium titanate powder at a temperature of 600°C or higher and 1200°C (step (ii)) after step (i). It is presumed that by further heating at a temperature of 600°C or higher and 1200°C after step (i), the absolute number of OH functional groups on the surface of the calcium titanate particles decreases, thus making it easier to obtain powder with a (b) / (a) ratio of 1.02 to 1.26. Furthermore, if the temperature is 600°C or higher and 1200°C, while controlling (b) / (a) within a suitable range, the final powder is also more likely to maintain a high average sphericity.

[0073] As a heating device, an electric furnace, gas furnace, etc., can be used. Furthermore, process (ii) is preferably carried out in the atmosphere. Additionally, the heating time is preferably 1 to 24 hours, more preferably 1 to 12 hours. If the heating time is 1 to 24 hours, productivity tends to be good.

[0074] By heating spheroidized calcium titanate powder, especially at 600–1000 °C for 2–6 hours, it is easier to obtain powder with a (b) / (a) ratio of 1.02–1.26. The powder obtained by this method is more likely to maintain a low dielectric loss tangent over a long period. Furthermore, the relative permittivity of the powder is more easily increased.

[0075] In one embodiment, after step (ii), the resulting spherical calcium titanate powder forms an agglomerate. Therefore, it may be possible to break up such an agglomerate.

[0076] In one embodiment, from the viewpoint of easily forming powder with a higher relative permittivity, it is preferable not to perform crushing that causes the average particle size (D50) of the resulting powder to change by more than 20% after step (ii), and it is preferable to recover the powder without performing crushing treatment after step (ii).

[0077] For spherical calcium titanate powder, a crushing process that reduces the D50 by 20% or more can be achieved, for example, by crushing the powder for 30 minutes or more using an agate mortar, ball mill, vibratory mill, jet mill, or wet jet mill. In the manufacturing method described in this embodiment, by not performing the crushing process described above for 30 minutes or more, or by not performing the crushing process at all, it is easy to obtain powder with a higher relative permittivity and also capable of achieving a low dielectric loss tangent.

[0078] Furthermore, in order to obtain spherical calcium titanate powder with a desired average particle size (D50), the manufacturing method of this embodiment may also include a step of classifying the spherical calcium titanate powder. As classification methods, examples include hydrocyclones, air classifiers, etc., in addition to classification using sieves.

[0079] Furthermore, it may also include a process of surface treating the spherical calcium titanate powder with a surface treatment agent, and a cleaning process for reducing impurities (such as the aforementioned anions) in the spherical calcium titanate powder.

[0080] In one embodiment, other spherical calcium titanate powders or powders of other inorganic metals or inorganic oxides with different specific surface areas and average particle sizes (D50) can be incorporated into or mixed with the spherical calcium titanate powder of this embodiment to prepare a mixed powder. By preparing a mixed powder, it is easier to adjust the relative permittivity, dielectric loss tangent, coefficient of thermal expansion, thermal conductivity, filling rate, etc., when mixed in a resin material according to the desired range. The powder of this embodiment also contains a mixed powder in which (b) / (a) is 1.02 or more.

[0081] In one embodiment, the adsorbed moisture content of the freshly manufactured spherical calcium titanate powder, as determined by the Karl Fischer method at a holding temperature of 200°C, is preferably 400 ppm or less, more preferably 350 ppm or less, and even more preferably 300 ppm or less. Furthermore, by performing the above-described drying treatment on 50 g of the obtained spherical calcium titanate powder, and then measuring the moisture content using a Karl Fischer moisture meter at a holding temperature of 200°C, the adsorbed moisture content immediately after manufacturing can be determined.

[0082] [use]

[0083] As described above, the spherical calcium titanate powder of this embodiment exhibits a small increase in dielectric loss tangent over time, and can maintain a low dielectric loss tangent for a long period. Such powder is suitable for use as a resin filler (a filler material for resins, especially a ceramic filler for high-frequency band sealing materials). In a preferred embodiment, it can also be used as a material (ceramic filler) for 5G communications, such as integrated packaging.

[0084] [Resin Composition]

[0085] The resin composition of this embodiment includes the above-mentioned spherical calcium titanate powder and at least one resin selected from thermoplastic resins and thermosetting resins.

[0086] The content of spherical calcium titanate powder in the resin composition is not particularly limited and can be appropriately adjusted according to the purpose. Even if a large amount of spherical calcium titanate powder of this embodiment is filled into the resin, its processability and workability are unlikely to be reduced. Therefore, the desired dielectric properties can be obtained by adjusting the mixing amount of powder in the resin composition. For example, when used as a substrate material for high-frequency bands or as an insulating material, the mixing amount can be in the range of 1 to 80% by mass relative to the total mass of the resin composition, and more preferably in the range of 10 to 70% by mass.

[0087] <Resin>

[0088] The resin composition of this embodiment includes at least one resin selected from thermoplastic resins and thermosetting resins. More specifically, examples include: polyethylene resin; polypropylene resin; epoxy resin; silicone resin; phenolic resin; melamine resin; urea resin; unsaturated polyester resin; fluororesin; polyamide resins such as polyimide resin, polyamide-imide resin, and polyether-imide resin; polyester resins such as polybutylene terephthalate resin and polyethylene terephthalate resin; polyphenylene sulfide resin; fully aromatic polyester resin; polysulfone resin; liquid crystal polymer resin; polyethersulfone resin; polycarbonate resin; maleimide-modified resin; ABS resin; AAS (acrylonitrile-acrylic rubber-styrene) resin; AES (acrylonitrile-ethylene-propylene-diene rubber-styrene) resin; hydrocarbon elastomer resin; polyphenylene ether resin; aromatic polyene resin, etc. One of these can be used alone, or two or more can be used in combination.

[0089] Without impairing the effects of this disclosure, the resin composition of this embodiment may also contain curing agents, curing accelerators, release agents, coupling agents, colorants, flame retardants, ion traps, etc.

[0090] <Manufacturing Method of Resin Composition>

[0091] The manufacturing method of the resin composition is not particularly limited and can be manufactured by stirring, dissolving, mixing, and dispersing the respective specified materials. The devices for mixing, stirring, dispersing, etc. of these mixtures are not particularly limited, and a kneader equipped with stirring and heating devices, a three-roll mill, a ball mill, a planetary mixer, etc. can be used. In addition, these devices can also be used in appropriate combination.

[0092] As described above, since the resin composition related to the present embodiment contains spherical calcium titanate powder with a small increase in the dielectric loss tangent over time, it can maintain a low dielectric loss tangent for a long time. In addition, the relative dielectric constant is also high. Such powder can also be used as, for example, the resin composition for the above-mentioned 5G communication materials.

[0093] Examples

[0094] Hereinafter, examples are illustrated to explain the present invention in detail, but the present invention is not limited by the following description.

[0095] [Example 1]

[0096] In the flame of LPG / O2 gas, by the powder melting method, the raw material powder (calcium titanate powder; manufactured by Kyoritsu Materials Co., Ltd., product name "CT-3", average sphericity of aggregates 0.78, average particle size (D50) 3.1 μm, specific surface area (BET) 1.82 m 2 / g) was spheroidized and then heat-treated at 600 °C for 4 hours. Thereafter, it was recovered without being subjected to a crushing treatment, and the spherical calcium titanate powder of Example 1 was obtained. For the obtained spherical calcium titanate powder, FT-IR analysis, determination of the average particle size (D50), specific surface area (BET), average sphericity, and adsorbed moisture content (after just being manufactured) were carried out according to the following conditions. Further, the temporal changes in the relative dielectric constant and dielectric loss tangent of the obtained powder were evaluated according to the following conditions. The results are shown in Table 1.

[0097] <FT-IR Analysis>

[0098] First, the spherical calcium titanate powder was filled into the sample tray until it was full, and using a Fourier transform infrared spectrophotometer (Frontier type infrared device manufactured by PerkinElmer Co., Ltd., product name "Spectrum One"), measurement was carried out by the diffuse reflection method in an atmospheric atmosphere (resolution 4.0 cm -1 , number of accumulations 64 times). Normalization was carried out at the wavenumber where the reflectance was the minimum value, and K-M transformation was carried out. According to the peak intensity at the wavenumber 3495 cm -1 of the obtained diffuse reflection spectrum and the wavenumber 3515 cm-1 The peak intensity was calculated, and the average value (a) was calculated. Next, the wavenumber 3505 cm⁻¹ was determined. -1 The ratio of the peak intensity (b) to the average value (a) above ((b) / (a)).

[0099] Furthermore, the diffuse reflectance spectrum obtained was found to exist at a wavenumber of 870 cm⁻¹. -1 Up to wave number 890cm -1 The peak intensity (c) of the absorption peak (C) is relative to the peak intensity at wavenumber 640 cm⁻¹. -1 Up to wave number 670cm -1 The ratio of the peak intensity (d) of the absorption peak (D) to the peak intensity (d) ((c) / (d)).

[0100] <Determination conditions for average particle size (D50)>

[0101] The average particle size was measured using a laser diffraction / scattering particle size distribution measuring device (product name "MT 3300 EXII" manufactured by Microtrac BEL Co., Ltd.). First, 80 cm³ of the sample was placed in a glass beaker. 3 Pure water and 0.1 g of spherical calcium titanate powder were dispersed for 1 minute using an ultrasonic homogenizer (SMT Co., Ltd., trade name "UH-600S" (homogenizer tip diameter: 20 mm φ)). The dispersion of the spherical calcium titanate powder was added dropwise to a laser diffraction / scattering particle size distribution measuring device using a dropper. The average particle size was measured 30 seconds after the start of the specified addition. The particle size distribution was calculated based on the intensity distribution of diffracted / scattered light from the spherical calcium titanate powder detected by the sensor in the laser diffraction / scattering particle size distribution measuring device. The D50 was calculated based on the cumulative particle size distribution corresponding to 50% of the particle size in the volumetric reference of the measured particle size.

[0102] <Conditions for determining specific surface area>

[0103] The BET specific surface area of ​​spherical calcium titanate powder was determined using the following method. First, 4 g of powder was filled into an empty tank and degassed at 300°C. After degassed, the tank filled with spherical calcium titanate powder was placed in a fully automated specific surface area measuring device (Mountech product name "Macsorb Model 1208") for specific surface area measurement. A He-N2 mixed gas was used for measurement, and the determination was performed at a main flow rate of 25 mL / min using a multi-point method.

[0104] <Conditions for determining mean sphericity>

[0105] The following steps were performed using a powder imaging analyzer (Spectris product name "FPIA-3000").

[0106] The sample was dispersed in pure water to obtain the test sample. The test sample was then flowed in the planar extension flow tank of the above-described apparatus, and an image of more than 200 spherical calcium titanate particles moving in the tank was recorded using an objective lens. The average sphericity was calculated from the recorded image and the following formula (1).

[0107] Mean sphericity = (π × HD / PM) 2 …(1)

[0108] In equation (1), HD represents the equivalent circle diameter of the particle, which is obtained by the ratio of the projected area of ​​the object particle to the area of ​​the circle. PM represents the projected circumference of the object particle. For the average sphericity, the "average sphericity" can be calculated first based on the average sphericity (π×HD / PM) of 200 spherical calcium titanate particles, and then the average sphericity can be squared to obtain the mean sphericity.

[0109] <Determination conditions for adsorbed moisture content>

[0110] 50g of spherical calcium titanate powder was weighed using a precision balance and placed in a small dryer, where it was dried at 100°C for 6 hours. The moisture content was then measured using a Karl Fischer moisture meter (product name "CA-310" manufactured by Nitto Seiko Analytech Co., Ltd.) at a maintained temperature of 200°C. The measurements were performed under a nitrogen atmosphere.

[0111] Next, the time-dependent changes in the relative permittivity and dielectric loss tangent of the resin composition containing spherical calcium titanate powder were measured under the following conditions, and the filler equivalent relative permittivity and dielectric loss tangent were determined.

[0112] <Determination conditions for dielectric properties (relative permittivity and dielectric loss tangent)>

[0113] First, the dielectric properties of freshly manufactured spherical calcium titanate powder were measured using a powder dielectric constant meter (KEYCOM Co., Ltd.'s product name "TM Cavity Resonator" (cylindrical cavity resonance method)). The dielectric properties were then measured in a PTFE resin bath (cylindrical, volume 1154 cm³). 3 Spherical calcium titanate powder was filled into the device in the range of 2.5~3.0g, and then placed in the device. The resonance peak at 1GHz was read, and the relative permittivity and dielectric loss tangent were measured.

[0114] Next, the dielectric loss tangent of powder stored in a desiccator at 25°C / 35%RH for 2 weeks (2 weeks after manufacturing), powder stored under the same conditions for 4 weeks (4 weeks after manufacturing), and powder stored under the same conditions for 10 weeks (10 weeks after manufacturing) were measured under the same conditions.

[0115] [Examples 2-3]

[0116] Spherical calcium titanate powder was prepared according to the manufacturing conditions shown in Table 1. For each example of spherical calcium titanate powder, FT-IR analysis was performed using the same method as in Example 1 to determine the average particle size (D50), specific surface area (BET), average sphericity, and adsorbed moisture content (freshly manufactured). Furthermore, the time-dependent changes in the relative permittivity and dielectric loss tangent of the obtained powder were evaluated under the same conditions as in Example 1.

[0117] [Comparative Examples 1-2]

[0118] The raw material powder was spheroidized according to the conditions shown in Table 1. Then, it was dried at 100°C for 1 hour to obtain the spherical calcium titanate powder of Comparative Example 1. Furthermore, the raw material powder was spheroidized according to the conditions shown in Table 1 and then subjected to heat treatment to obtain the spherical calcium titanate powder of Comparative Example 2.

[0119] For each example of spherical calcium titanate powder, FT-IR analysis was performed using the same method as in Example 1 to determine the average particle size (D50), specific surface area (BET), average sphericity, and adsorbed moisture content (freshly manufactured). Furthermore, the time-dependent changes in the relative permittivity and dielectric loss tangent of the obtained powders were evaluated under the same conditions as in Example 1. The results are shown in Table 1.

[0120] [Refer to Examples 1-2]

[0121] As a reference example 1, the analytical results of the raw material powder (FT-IR analysis, average particle size (D50), specific surface area (BET), average sphericity and adsorbed moisture content (right after manufacturing)) are shown in Table 1.

[0122] In addition, as a reference example 2, the analytical results of the spherical calcium titanate powder obtained by spheroidizing the raw material powder according to the conditions shown in Table 1 and then heating it at 1200°C for 4 hours are also shown in Table 1.

[0123] [Table 1]

[0124]

[0125] As shown in Table 1 and Figures 1-2As shown, in FT-IR analysis, the (b) / (a) values ​​of the spherical calcium titanate powders of Examples 1-3 were 1.02-1.26 (and (c) / (d) were also 5.0 or higher). On the other hand, the (b) / (a) values ​​of Comparative Example 1, which was not heated after the spheroidizing process, and Comparative Example 2, which was heated at 400°C after the spheroidizing process, exceeded 1.26. The results of investigating the dielectric properties of the powders in these examples showed that, compared with the powders of the comparative examples, the powders of Examples 1-3, with (b) / (a) in the range of 1.02-1.26, also had higher relative permittivity. Furthermore, in all cases after storage for 2 weeks, 4 weeks, and 10 weeks, the time-dependent increase in dielectric loss tangent was small, and a low dielectric loss tangent could be maintained.

[0126] Furthermore, as shown in Reference Example 2, the (b) / (a) ratio of the raw material powder (typical calcium titanate powder) is less than 1.02. While such powder has a very high relative permittivity, its dielectric loss tangent shows a significant increase over time. Additionally, Reference Example 1 shows the analysis results of the powder after spheroidization and heat treatment at 1200°C. The (b) / (a) ratio of the powder in Reference Example 1 after spheroidization and heat treatment at 1200°C is less than 1.02. Although such powder also has a high relative permittivity and a smaller increase over time in dielectric loss tangent, its average sphericity decreases significantly. Therefore, there is a concern about a decrease in resin filling performance when used as a ceramic filler.

[0127] Based on the above results, it is confirmed that the spherical calcium titanate powder of this embodiment has excellent resin filling properties, a higher relative permittivity, and a smaller increase in dielectric loss tangent over time, thus enabling it to maintain a low dielectric loss tangent for a long period of time.

[0128] The following is a non-limiting list of exemplary embodiments of this disclosure and combinations thereof.

[0129] [1] A spherical calcium titanate powder, wherein the wavenumber of the powder measured by diffuse reflectance FT-IR is 3505 cm⁻¹. -1 Peak intensity (b) relative to wavenumber 3495 cm⁻¹ -1 Peak intensity and wavenumber 3515cm -1 The ratio of the average peak intensity (a) to (b) (a) is 1.02 to 1.26.

[0130] [2] The spherical calcium titanate powder according to [1], wherein the average particle size (D50) is 0.5 to 15 μm.

[0131] [3] The spherical calcium titanate powder according to [1] or [2], wherein the average sphericity is 0.80 or higher.

[0132] [4] The spherical calcium titanate powder according to any one of [1] to [3], wherein the specific surface area (BET) is 1.0 m². 2 / g or less.

[0133] [5] The spherical calcium titanate powder according to any one of [1] to [4] is used for resin filling.

[0134] [6] A resin composition comprising spherical calcium titanate powder as described in any one of [1] to [5] and at least one resin selected from thermoplastic resins and thermosetting resins.

[0135] [7] The resin composition according to [6] is a material for 5G communication.

[0136] Industrial availability

[0137] The spherical calcium titanate powder of this embodiment exhibits a small increase in dielectric loss tangent over time, and can maintain a low dielectric loss tangent for a long period. Such powder is industrially feasible as a resin filler (a filler material for resins, especially a ceramic filler for high-frequency band sealing materials).

Claims

1. A spherical calcium titanate powder, wherein the wavenumber of the powder measured by diffuse reflectance Fourier transform infrared spectroscopy is 3505 cm⁻¹. -1 The peak intensity b relative to the wavenumber 3495 cm⁻¹ -1 Peak intensity and wavenumber 3515cm -1 The ratio of the average peak intensity a to the mean peak intensity b / a is 1.02 to 1.

26.

2. The spherical calcium titanate powder according to claim 1, wherein, The average particle size D50 is 0.5–15 μm.

3. The spherical calcium titanate powder according to claim 1 or 2, wherein, The average sphericity is above 0.

80.

4. The spherical calcium titanate powder according to claim 1 or 2, wherein, The specific surface area (BET) is 1.0 m². 2 / g or less.

5. The spherical calcium titanate powder according to claim 1 or 2, which is used as a resin filler.

6. A resin composition comprising the spherical calcium titanate powder of claim 1 or 2 and at least one resin selected from thermoplastic resins and thermosetting resins.

7. The resin composition according to claim 6, which is used as a material for 5G communication.

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