A powder made of calcium titanium complex oxide, a method for producing the same, and a resin composition filled with the powder.

Abstract

To provide a calcium titanium complex oxide powder suitable as a filler for resin compositions, which does not impair the fluidity of the resin or increase its brightness when added to the resin composition, a method for producing the same, and a resin composition filled with the powder. [Solution] In X-ray diffraction, the crystallite size of the CaTiO3 crystal peak appearing in the diffraction angle 2θ range of 22.00° to 24.00° is 60.0 nm to 98.0 nm, and the circularity determined from scanning electron microscope images of the particles in the powder is 0.88 or higher. 50 A powder made of calcium titanium complex oxide with a diameter in the range of 2.0 μm to 15.0 μm and an L* value of 88.0 or less. It can be manufactured by a method that includes subjecting a titanium source to spray drying, mixing the spray-dried titanium source with a calcium source, and calcining the mixture at a temperature of 1000°C to 1800°C.

Description

[Technical Field]

[0001] This invention relates to a powder made of calcium titanium complex oxide, a method for producing the same, and a resin composition filled with the powder. [Background technology]

[0002] Inorganic fillers for semiconductor encapsulants, such as those made from titanium oxides like barium titanium complex oxide and calcium titanium complex oxide, have been used in a wide range of applications, including automotive parts, home appliances, and other fields that utilize semiconductors. Among these, calcium titanium complex oxide, in particular, has a high dielectric constant and has been widely used because no adverse effects on the human body have been confirmed, enabling the creation of encapsulants with high dielectric constants. Simultaneously, these encapsulants have played a role in protecting semiconductor elements from external environmental factors such as mechanical forces like shock and pressure, reactive gases like water vapor and oxygen in the air, heat, and ultraviolet light. In recent years, with the miniaturization and increased performance of semiconductors, research has been conducted to further improve their properties. One method for improving properties is to increase the filling density of fillers with high dielectric constants. By increasing the content of fillers with high dielectric constants, it is possible to improve the dielectric constant of the encapsulant, as well as improve properties such as strength, rigidity, heat resistance, and dimensional stability.

[0003] However, generally, increasing the filler content reduces the fluidity of the resin composition after the filler is added, worsening the moldability of the resin composition and making production with existing equipment difficult. It also tends to induce problems such as an increase in molding defects. In order to maintain the fluidity of the resin composition after the addition of the filler, it is generally considered to use particles with a large particle size as the filler. As calcium titanium complex oxide particles with a relatively large particle size, for example, paragraph 0041 and examples of International Publication No. 2010 / 027074 (Patent Document 1) describe a method of obtaining calcium titanate powder with an average particle size of 1.04 μm to 10.7 μm by mixing calcium carbonate and titanium oxide in a Ca:Ti molar ratio within the range of 45:55 to 55:45, firing the mixture at a temperature within the range of 1150 to 1500°C, and then grinding the fired product to a predetermined average particle size. However, simply mixing a titanium source and a calcium source and firing them at a temperature of 1000°C or higher, as in Patent Document 1, can result in calcium-titanium complex oxide particles that are rectangular in shape. Adding non-spherical particles can reduce the fluidity of the resin composition after addition, even if the particle size is large.

[0004] Furthermore, paragraphs 0030 to 0042 of Japanese Patent Publication No. 2024-095439 (Patent Document 2) describe a method in which a titanium source and a calcium source are mixed and subjected to primary calcination at 800 to 1500°C, followed by pulverization and / or classification, and then the powder is supplied into a flame (so-called flame method) to spheroidize the powder, and further secondary calcination is performed. In the example, it is stated that calcium titanate powder with an average particle size (D50) of 5.9 μm or more and 6.8 μm or less and a degree of spheroidization of 0.96 or more and 0.98 or less was obtained. However, the flame method described in Reference Document 2 is a method that makes it difficult to reduce manufacturing costs due to the supply rate of raw materials and the amount of gas consumed. In addition, inorganic compounds that have been spheroidized in a high-temperature flame tend to result in a resin composition that is close to white in color when added to a resin. Generally, in semiconductor encapsulants, black is preferred for the purpose of blocking light and improving laser markability, and it is common to add colorants such as carbon black or organic synthetic dyes to make them black. However, if the resin composition exhibits a color close to white, the amount of colorant added to achieve black color becomes larger. A large amount of colorant added to the resin composition can lead to problems such as increased viscosity, changes in electrical properties, or elution of colorant components. Therefore, regardless of the colorant used, it is preferable to keep the amount of colorant added as small as possible. Generally, a smaller L* value in the L*a*b* color coordinate system of the resin composition used as the encapsulant material allows for a smaller amount of colorant to be added to achieve black color in the encapsulant. For these reasons, there is a need for calcium titanium complex oxide particles that have a moderately large particle size, high circularity, and can keep the L* value of the resin composition low after addition. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2010 / 027074 [Patent Document 2] Japanese Patent Publication No. 2024-095439 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention aims to provide a powder made of calcium titanium complex oxide that has a moderately large particle size, high circularity, and can keep the L* value of the resin composition after addition to a small value, as well as a method for producing the same. [Means for solving the problem]

[0007] The inventors have conducted extensive research to achieve the above objective and have found that by spray-drying a titanium source, mixing the resulting spray-dried material with a calcium source, and then firing it at a temperature of 1000°C to 1800°C, they have achieved a method that is unprecedented in that the crystallite size is between 60.0 nm and 98.0 nm, and the median particle size by volume (hereinafter referred to as "D") 50 A new powder made of calcium titanium complex oxide was created, having a particle diameter (hereinafter referred to as "diameter") of 2.0 μm or more and 15.0 μm or less, a circularity of 0.88 or more as determined from scanning electron microscope (SEM) images of the particles, and a low L* value. This powder does not impair the fluidity of the resin composition even when added to the resin as a filler, and it was possible to keep the L* value of the resin composition low when added to the resin under the conditions described later. The present invention includes, but is not limited to, the following.

[0008] <Aspect 1> In X-ray diffraction measurements, the crystallite size of the CaTiO3 crystal peak appearing in the diffraction angle 2θ range of 22.00° to 24.00° is in the range of 60.0 nm to 98.0 nm, and the circularity determined from scanning electron microscope images of the particles constituting the powder is 0.88 or higher. 50 A powder made of calcium titanium complex oxide, having a diameter in the range of 2.0 μm to 15.0 μm and an L* value of 88.0 or less. <Aspect 2> A powder comprising calcium titanium complex oxide according to Embodiment 1, having an apparent density in the range of 0.85 g / mL to 1.45 g / mL. <Aspect 3> A powder composed of a calcium titanium complex oxide according to Embodiment 1 or 2, having an oil absorption amount of 25.0 g / 100 g or less when boiled in oil. <Embodiment 4> A powder composed of a calcium titanium complex oxide according to any one of Embodiments 1 to 3, wherein when an evaluation resin composition is produced using the powder composed of a calcium titanium complex oxide according to the method described in the examples, the L* value of the evaluation resin composition is 78.0 or less. <Embodiment 5> A powder composed of a calcium titanium complex oxide according to any one of Embodiments 1 to 4, wherein when an evaluation resin composition is produced using the powder composed of a calcium titanium complex oxide according to the method described in the examples, the melt flow rate of the evaluation resin composition is 150 g / 10 min or more. <Embodiment 6> A step of subjecting a titanium source to spray drying A step of mixing the spray-dried product of the obtained titanium source and a calcium source, and A step of firing the obtained mixture at 1000 °C or higher and 1800 °C or lower A method for producing a powder composed of a calcium titanium complex oxide, comprising <Embodiment 7> A method for producing a powder composed of a calcium titanium complex oxide according to Embodiment 6, wherein the titanium source is metatitanic acid. <Embodiment 8> A resin composition containing a powder composed of a calcium titanium complex oxide according to any one of Embodiments 1 to 5. <Embodiment 9> A sealing material containing a powder composed of a calcium titanium complex oxide according to any one of Embodiments 1 to 5.

Advantages of the Invention

[0009] The calcium titanium complex oxide particles obtained in this invention have a large particle size and a spherical shape. Therefore, even after being added to a resin as a filler, they do not impair the fluidity of the resin composition, and the filling rate into the resin can be increased while maintaining various properties of the resin composition, such as fluidity. Furthermore, since the powder of this invention can keep the L* value of the resin composition low, the amount of colorant added when making the resin composition black in applications such as encapsulants can be reduced. In addition, the powder consisting of calcium titanium complex oxide particles obtained in this invention tends to have an apparent density within a moderate range, so it does not significantly affect the density or specific gravity of the resin composition in which the powder is filled, and has the advantage of being easy to use. Moreover, the powder of this invention is suitable as a filler for resin compositions because its particle size and particle shape are controlled. [Brief explanation of the drawing]

[0010] [Figure 1] This is an SEM image (magnification 20,000x) of powder 3 obtained in Example 3. [Figure 2] This is an SEM image (observation magnification 3000x) of powder 5 obtained in Example 5. [Figure 3] This is a cumulative particle size distribution diagram of powder 6 obtained in Example 6. [Figure 4] This is the X-ray diffraction pattern of powder 6 obtained in Example 6. [Modes for carrying out the invention]

[0011] [Powder consisting of calcium titanium complex oxide] The powder of the present invention consists of calcium titanium complex oxide, the crystallite size of CaTiO3 is 60.0 nm or more and 98.0 nm or less, and the circularity determined from SEM observation images of the particles constituting the powder is 0.88 or more. 50The particles have a diameter in the range of 2.0 μm to 15.0 μm and an L* value of 88.0 or less. "Powder consisting of calcium titanium complex oxide" means that the particles constituting the powder are mainly calcium titanium complex oxide, or that the proportion of calcium titanium complex oxide in the composition of individual particles is large. Specifically, it refers to powder in which the proportion of calcium titanium complex oxide is 900 g / kg or more, preferably 950 g / kg or more.

[0012] The powder of the present invention has a crystallite size of 60.0 nm to 98.0 nm at the CaTiO3 crystal peak that appears in the diffraction angle 2θ range of 22.00° to 24.00° in X-ray diffraction measurements. If the crystallite size is within the above range, the sintering of the primary particles proceeds, providing sufficient strength to withstand addition to resin, and the L* value of the powder becomes smaller, making it easier to keep the L* value of the resin composition to which the powder of the present invention is added to a small value. The lower limit of the crystallite size is more preferably 68.0 nm or more, even more preferably 70.0 nm or more, and even more preferably 71.0 nm or more. The upper limit of the crystallite size is more preferably 90.0 nm or less, even more preferably 85.0 nm or less, even more preferably 80.0 nm or less, even more preferably 75.0 nm or less, and most preferably 74.5 nm or less. The crystallite size can be evaluated by the method described in the examples below.

[0013] The particles constituting the powder of the present invention have a spherical shape. Specifically, the circularity determined from SEM observation images of the particles constituting the powder is 0.88 or higher. The greater the circularity, the better the dispersibility in the resin composition, and the less likely it is to impair the fluidity of the resin composition even when the amount added is large. The lower limit is more preferably 0.90 or higher. There is no particular upper limit to the circularity of the particles, but theoretically, the maximum is 1.00. The circularity can be evaluated by the method described in the examples below.

[0014] The particles constituting the powder of the present invention have a median particle size (D) based on volume. 50 The diameter is between 2.0 μm and 15.0 μm. 50If the diameter is within the above range, it is less likely to impair the fluidity of the resin composition when added to the resin. The lower limit is more preferably 3.0 μm or more, even more preferably 5.0 μm or more, and even more preferably 6.0 μm or more, and the upper limit is more preferably 10.0 μm or less, and even more preferably 8.0 μm or less. D 50 The diameter can be evaluated by the method described in the examples below.

[0015] The L* value of the powder of the present invention in the L*a*b* color coordinate system is 88.0 or less. Generally, a smaller L* value for the powder allows for a smaller L* value in the resin composition when the powder is added, and a smaller L* value for the resin composition allows for a smaller amount of colorant to be added when producing a black product. This is because a lower brightness in the resin composition makes it easier to produce a black color with a colorant. The upper limit of the powder's L* value is more preferably 87.0 or less, even more preferably 83.0 or less, and even more preferably 75.0 or less. Furthermore, the L* value of the resin composition after adding the powder, as measured by the method described in the examples, is preferably 78.0 or less. The upper limit of the resin composition's L* value is more preferably 70.0 or less, even more preferably 65.0 or less, and even more preferably 60.0 or less. There is no particular lower limit to the L* value for either the powder or the resin composition after powder addition, but theoretically, the lower limit is 0. The L* values ​​of the powder and the resin composition after powder addition can be evaluated by the method described in the examples below.

[0016] The powder of the present invention preferably has an apparent density in the range of 0.85 g / mL to 1.45 g / mL. 50 Within the range of diameter, particle circularity, and crystallite size, an apparent density within the above range is suitable for use because it maintains fluidity while preventing the density of the resulting resin composition from becoming too high. The lower limit is more preferably 0.90 g / mL or higher, even more preferably 0.95 g / mL or higher, and the upper limit is more preferably 1.30 g / mL or lower, even more preferably 1.25 g / mL or lower, even more preferably 1.20 g / mL or lower, and most preferably 1.10 g / mL or lower. The apparent density can be evaluated by the method described in the examples below.

[0017] Similarly, the green density when pressurized to 50 MPa is greater than 1.60 g / cm 3 and less than or equal to 2.90 g / cm 3 and preferably within the following range. The lower limit is more preferably 1.70 g / cm 3 or more, and the upper limit is more preferably 2.40 g / cm 3 or less, still more preferably 2.38 g / cm 3 or less, even more preferably 2.35 g / cm 3 or less, and most preferably 2.30 g / cm 3 or less. The green density when pressurized to 50 MPa can be evaluated by the method described in the examples below.

[0018] Note that the green density when pressurized to 100 MPa is 1.80 g / cm 3 or more and 3.10 g / cm 3 or less, and preferably within the following range. The lower limit is more preferably 1.90 or more, and the upper limit is more preferably 2.70 g / cm 3 or less, still more preferably 2.55 g / cm 3 or less, even more preferably 2.40 g / cm 3 or less, and most preferably less than 2.30 g / cm 3 is preferred.

[0019] The calcium titanium complex oxide powder of the present invention preferably has a boiled linseed oil absorption amount of 25.0 g / 100 g or less. The boiled linseed oil absorption amount of the powder corresponds to the amount of resin components constrained between particles when mixed with resin. When the boiled linseed oil absorption amount is within the above range, the amount of resin components constrained between particles is small, so the effect of inhibiting the behavior of the resin components is reduced, and therefore the fluidity of the resin composition tends to be easier to maintain even after the addition of the powder. The upper limit is more preferably 24.0 g / 100 g or less, even more preferably 19.0 g / 100 g or less, and even more preferably 15.0 g / 100 g or less. The lower limit of the boiled linseed oil absorption amount is not particularly limited, but as a guideline, it is 8.0 g / 100 g or more. The boiled linseed oil absorption amount can be evaluated in accordance with JIS K 5101-13-2:2004. Specifically, it can be evaluated by the method described in the examples below.

[0020] When the powder of the present invention is added to a resin by the method described in the examples, the melt flow rate of the resin composition is preferably 150 g / 10 min or higher. A melt flow rate of 150 g / 10 min or higher makes it easier to maintain the fluidity of the resin composition necessary for trouble-free production even after the addition of the powder. The lower limit is more preferably 170 g / 10 min or higher, even more preferably 200 g / 10 min or higher, and even more preferably 250 g / 10 min or higher. There is no particular upper limit to the melt flow rate, but as a guideline, it should be 500 g / 10 min or lower. Note that a larger melt flow rate value means that the resin composition has greater fluidity. The melt flow rate can be evaluated by the method described in the examples below.

[0021] The powder of the present invention preferably has a narrow particle size distribution. The particle size distribution is preferably such that the SD value, as evaluated by the method described in the examples, is 5.2 μm or less. Within this range, the content of fine and coarse particles is small, making it easier to use stably as a filler added to resins. A smaller SD value indicates a narrower particle size distribution. The upper limit of the SD value is preferably 4.8 μm or less. The lower limit is not particularly limited, but theoretically, the lower limit is 0 μm. The particle size distribution (SD value) can be evaluated by the method described in the examples below.

[0022] Furthermore, the proportion of particles with a particle diameter of 1.0 μm or less among the particles constituting the powder of the present invention is preferably less than 50 mL / L by volume, more preferably 40 mL / L or less, and even more preferably 30 mL / L or less.

[0023] The surface of the particles constituting the powder of the present invention preferably contains a calcium content that is not too low compared to titanium. Specifically, the molar ratio of calcium to titanium measured by X-ray photoelectron spectroscopy is preferably such that calcium is greater than 0.93 times the amount of titanium, more preferably 0.95 times or more, and even more preferably 0.98 times or more. X-ray photoelectron spectroscopy is a means that can quantitatively measure the components of the powder surface within a few nanometers.

[0024] (Manufacturing method) The following is an example of a method for producing a powder made of calcium titanium complex oxide, which has a moderately large particle size, high circularity, and can keep the L* value of the resin composition after addition low, as is the case with the powder of the present invention. However, the method for producing the powder of the present invention is not limited to the following.

[0025] The method for producing the powder of the present invention is not particularly limited, but a typical method involves first subjecting only the titanium source among the raw materials to spray drying, and then mixing the resulting spray-dried titanium source with a calcium source and subsequently calcining it.

[0026] Furthermore, in the above manufacturing method, it is also possible to obtain spherical strontium-titanium complex oxide particles or magnesium-titanium complex oxide particles by changing the calcium source to a strontium source or a magnesium source.

[0027] The titanium source is not particularly limited, but typical examples include anatase-type titanium dioxide, rutile-type titanium dioxide, titanium dioxide having two phases (anatase-type and rutile-type), metatitanic acid, sodium titanate, and titanium sulfate. Multiple titanium sources may be combined, and the selection should be made considering the particle density after spray drying and the reactivity with the calcium source. Generally, it is desirable that the titanium source contains a small amount of substances that may remain as impurities in the resulting calcium-titanium complex oxide. The titanium source may be pre-calcined.

[0028] In particular, using an acid-dissolved metatitanic acid as the titanium source is preferable because it yields dense granules. Furthermore, it is preferable if the micelle diameter of the metatitanic acid used is 80 nm or less, as this makes it easier to obtain calcium titanium complex oxide particles with a dense interior. There are no limitations on the method for measuring the micelle diameter of metatitanic acid, but observation using a transmission electron microscope is a typical example. In general, the optimal raw material should be selected considering factors such as production equipment, required properties, and cost.

[0029] When subjecting a titanium source to spray drying, first, the titanium source is dispersed in water to form a slurry. If the solid content concentration of the slurry is between 100 g / L and 500 g / L, D 50It is preferable that the diameter does not become too large, the particle size distribution is good, and production is efficient without clogging the nozzles of the spray dryer. Furthermore, since an acidic slurry pH would corrode the spray dryer and calcination equipment, it is preferable that the slurry pH of the titanium source be 6.0 or higher. In addition, polyvinyl alcohol, carboxymethylcellulose, starch, etc. may be added as a binder to improve the strength of the granulated material after spray drying. It is preferable that the amount of binder added is between 2 g / kg and 5 g / kg, as this maintains the viscosity of the slurry within an appropriate range and disperses the titanium source in the slurry. A dispersant may also be added to disperse the titanium source. By dispersing the titanium source in the slurry, it is possible to form a dense spray-dried material with spherical particle shapes through spray drying.

[0030] The titanium source slurry is spray-dried using a spray dryer. Generally speaking, it is preferable to use a two-fluid nozzle on the spray dryer to obtain granules with a particle size of 15.0 μm or less. A lower slurry supply rate results in smaller particle sizes but reduces production efficiency. As a guideline, it is preferable to adjust the rate as appropriate within the range of 120 mL / min to 300 mL / min. Furthermore, an outlet temperature of 100°C or higher is preferable because it reduces the water content of the granules and makes them less likely to break down. Obtaining dense spherical spray-dried material at this stage leads to obtaining calcium titanium complex oxide particles with desired characteristics such as particle shape and apparent density.

[0031] The spray-dried titanium source may undergo primary calcination before mixing with the calcium source. Primary calcination increases the strength of the granules, making them less prone to crumbling. While the conditions for primary calcination are not particularly limited, it is preferable to perform it in air. If the calcination temperature is 1000°C or lower, the composition of the calcined material will not be a single phase of rutile-type titanium dioxide, resulting in good reactivity with the calcium source. While there is no particular lower limit to the calcination temperature, as a guideline, calcination proceeds easily at temperatures above 500°C. While there is no particular limit to the calcination time, as a guideline, a time of 0.25h to 10.00h will yield the desired calcination effect and good productivity. The calcination furnace should be selected considering the characteristics of the resulting calcined material and productivity, and may include batch-type electric furnaces or continuous-type roller hearth kilns.

[0032] Next, the spray-dried titanium source is mixed with the calcium source. The calcium source is not particularly limited, but calcium salts such as calcium hydroxide, calcium carbonate, calcium chloride, and calcium sulfate can be used. Generally, it is desirable that the calcium source contains a small amount of substances that remain as impurities in the product. Calcium hydroxide Ca(OH)2 is particularly preferred because it exhibits strong alkalinity when dissolved in aqueous solution, which reduces the amount of alkali added, and because it has a large amount of calcium per unit mass.

[0033] When mixing the titanium source and the calcium source, the amount of calcium is preferably greater than 1.00, and more preferably 1.05 or greater, when the amount of titanium is set to 1.00. By making the amount of calcium greater than the amount of titanium during mixing, the amount of unreacted titanium-containing substances, including titanium dioxide, remaining in the powder after subsequent calcination can be reduced. Although not fully understood, it is thought that by adding an excess of calcium relative to titanium when mixing the spray-dried titanium source with the calcium source, the spray-dried individual titanium sources are more likely to come into contact with the calcium source. On the other hand, if the amount of calcium added is excessively large, the cost of obtaining the same mass of calcium-titanium complex oxide will increase. Although it cannot be said definitively, when the amount of calcium is set to 1.00, the amount of calcium is preferably 3.00 or less, more preferably 2.00 or less, and even more preferably 1.60 or less, as this allows for low-cost production.

[0034] The spray-dried titanium source can be mixed with the calcium source by any method, regardless of whether or not primary calcination has been performed, but wet mixing is preferred. Mixers, mills, and other equipment can be used as needed during mixing. Equipment that does not disrupt the particle shape of the spray-dried titanium source should be selected by evaluating a small amount beforehand. If it is necessary to crush the calcium source to improve reactivity, it can be crushed by any method. There are no particular restrictions on the procedure as long as the spray-dried titanium source and the crushed calcium source are ultimately mixed. Even if the molar ratio of titanium to calcium is appropriate, if the spray-dried titanium source and calcium source are not uniformly mixed, the desired calcium-titanium complex oxide particles may not be obtained; therefore, uniform mixing is desirable. It is preferable that the slurry after mixing is not only uniform from a macroscopic perspective, but also that the individual particles of the spray-dried titanium source and calcium source are uniformly mixed.

[0035] As mentioned above, it is preferable to mix the spray-dried titanium source and the calcium source wet. However, dry mixing is also acceptable if it is possible to agitate the spray-dried titanium source without disrupting its particle state and to uniformly mix each individual particle.

[0036] When mixing the spray-dried titanium source with the calcium source, an alkali may be added to adjust the slurry's pH to prevent the calcium source from leaching into the slurry. The alkali used can be a compound containing alkali metals or alkaline earth metals such as sodium, potassium, and calcium. Hydroxides of these metals are particularly preferred. Furthermore, considering solubility and usability, compounds containing sodium or potassium are even more preferred. Two or more of these compounds may be used in combination.

[0037] The mixture of the spray-dried titanium source and the calcium source is held under atmospheric pressure and at room temperature while being stirred. The holding time varies depending on the scale, container shape, and concentration, but as a guideline, it is between 1.0h and 30.0h. The lower limit is more preferably 2.0h or more, and even more preferably 3.0h or more. The upper limit is more preferably 20.0h or less.

[0038] After holding is complete, the slurry is separated into solid and liquid by filtration. The filtration method is not particularly limited and can be carried out using known methods such as using a filter press, using a Nutsche filter, or using centrifugal separation. Washing may also be combined with the filtration process. Unless otherwise specified, deionized water should be used for washing. A coagulant may be added as needed.

[0039] Next, the mixture of the spray-dried titanium source and the calcium source is calcined. The conditions for calcining the mixture are not particularly limited, but it is preferable to do so in the atmosphere. If the calcination temperature is between 1000°C and 1800°C, the sintering of the powder will progress and its strength will increase, resulting in a powder with a spherical particle shape and a small L* value. The lower limit is more preferably 1050°C or higher, and the upper limit is more preferably 1200°C or lower, even more preferably 1160°C or lower, and even more preferably 1150°C or lower, from the viewpoint of cost and safety. By calcining, the irregularities of the particles disappear and the crystallite size increases, so by adjusting the calcination conditions, a spherical powder with a small L* value can be obtained. The calcination time of the mixture is not particularly limited, but as a guideline, it is preferable to calcinate it for 1.0h to 10.0h from the viewpoint of completing the reaction while preventing the crystallite size from becoming too large. The lower limit is more preferably 2.5 hours or more, even more preferably 3.0 hours or more, and the upper limit is more preferably 8.0 hours or less, even more preferably 7.0 hours or less.

[0040] After the calcination of the mixture, the calcium-titanium complex oxide powder may have impurities, such as calcium compounds, on its particle surface after the reaction between the titanium source and the calcium source. Therefore, an acid treatment step may be included to wash the powder with acid. The acid treatment can remove impurities near the particle surface. In addition, the acid treatment removes sodium and calcium, which are in a state that is easily released, and reduces the amount of these ions that leach into the resin components after the powder is added to the resin. The type of acid and pH are not particularly limited, but it is preferable to use mineral acids such as hydrochloric acid because they are inexpensive and do not easily remain on the surface of the calcium-titanium complex oxide particles. The powder may be washed with water before washing with acid. Furthermore, the acid washing and water washing may be repeated alternately, for example, washing with acid, washing with water, and then washing with acid again. Also, the acid washing may be performed before or after the calcination process, and may be performed multiple times. The order of filtration, washing, calcination, and acid treatment can be appropriately determined considering factors such as the required amount of ion elution and cost.

[0041] The powder may be coated with an organic or inorganic layer on its surface. The organic layer can improve, for example, the dispersibility in the resin component and the strength of the resin composition, while the inorganic layer can improve, for example, the fluidity of the powder and fine-tune the dielectric constant to a desired value. Examples of organic materials include silicone compounds such as dimethylpolysiloxane, hydrogen dimethicone, and polysiloxane, fluorine compounds represented by silanes and perfluoroalkyl phosphate compounds, hydrocarbons, lecithin, amino acids, polyethylene, wax, and metal soaps. Examples of inorganic materials include amorphous silica represented by colloidal silica, crystalline silica, and hydrated oxides or oxides of metals such as aluminum, silicon, zinc, titanium, zirconium, iron, cerium, and tin. Furthermore, examples of coupling agents include aluminum-based, titanium-based, and zirconium-based agents. Multiple of these treatments may be combined, and there are no particular restrictions on the order of treatment. The surface treatment method is not particularly limited, and any conventional method may be used. For example, a coating layer can be formed by mixing the coating material with the powder and then heat-treating it. Since surface treatment can change electrical properties such as dielectric constant, it is generally desirable that the mass of the coating layer be 100 g / kg or less of the powder when a coating layer is provided.

[0042] The powder obtained after calcination or drying may be crushed as appropriate. The crushing method is not particularly limited. Known methods such as ball mills, vibration mills, jet mills, and hammer mills can be used without restriction. The crushing method should be determined considering the particle size, the proportion of coarse particles in the crushed product, cost, etc. In addition, an auxiliary agent may be added before crushing to effectively promote crushing. Examples of auxiliary agents include silicone compounds such as dimethylpolysiloxane, hydrogen dimethicone, and polysiloxane; coupling agents such as silane-based, aluminum-based, titanium-based, and zirconium-based compounds; fluorine compounds represented by perfluoroalkyl phosphate compounds; hydrocarbons; lecithin; amino acids; polyethylene; wax; and metal soaps. Multiple auxiliary agents may be combined, and there is no particular restriction on the order of addition. The method of addition is not particularly limited, but generally, a method of adding the auxiliary agent while stirring the powder slurry is used. Furthermore, classification or other operations may be performed after crushing. These operations are not limited in any way.

[0043] (Application) The powder of the present invention can be used as a filler in resin compositions, although this is not limited to the present invention. For example, it can be added as a filler to a resin composition mainly composed of a thermosetting resin. Resin compositions containing the powder of the present invention can be used in a variety of applications. The powder of the present invention has a particle size of appropriate size and a high degree of circularity, so it does not impair the fluidity of the resin composition even after being blended into it. Furthermore, even after being added to the resin, the L* value of the resin composition is low, so the amount of colorant added to make the resin composition black is small. In addition, the apparent density tends to be within an appropriate range, so it does not significantly affect the density or specific gravity of the resin composition containing the powder. Due to these characteristics, it is easy to use the powder of the present invention in a larger filling amount than conventional products when adding it to a resin composition. By increasing the filling amount of the powder, it is possible to obtain a resin composition with a high dielectric constant. Furthermore, resin compositions with a large filling amount of the powder of the present invention tend to have high heat resistance and a low coefficient of thermal expansion in addition to a high dielectric constant, so they are useful in fields such as antenna substrates where low thermal expansion is required.

[0044] Furthermore, a resin composition containing the powder of the present invention can be used, for example, as a encapsulant. The powder of the present invention is particularly suitable as a filler in resin compositions used as resin encapsulants for electrical and electronic components, and can impart high dielectric constant and heat resistance to the resin composition. As described above, the powder of the present invention can be highly filled into resin compositions, and is useful for obtaining higher performance resin compositions and resin compositions with low thermal expansion. A typical example is its use as a resin encapsulant for semiconductors. The composition of the resin components in the resin encapsulant for semiconductors is not particularly limited. In addition, the encapsulant may contain fillers other than the powder of the present invention, or other components such as flame retardants, in the resin composition.

[0045] The powder of the present invention can also be used in the usual applications of calcium titanium complex oxide, such as ceramic capacitors, external additives for electrophotographic image forming apparatus, pigments, rubber fillers, friction materials, and cosmetics. The powder consisting of calcium titanium complex oxide in the present invention is D 50 These are spherical particles with a diameter of several micrometers and a small L* value. In particular, for rubber fillers, if a white coloration in the product is undesirable, there is the advantage that the amount of colorant added can be reduced, similar to the case of the resin composition described above. [Examples]

[0046] [Evaluation Method] [crystallite size] X-ray diffraction measurements were performed using the powder method with a Rigaku RINT-TTR III X-ray diffractometer. The sample was ground in a mortar and packed into a cell at approximately 1.5 g ± 0.2 g. The starting angle was 10.0000°, the ending angle was 75.0000°, the sampling width was 0.0200°, the scan speed was 4.0000° / min, the diverging slit was 0.5°, the scattering slit was 0.5°, the receiving slit width was 0.15 mm, and characteristic X-rays were obtained using copper as the cathode with a wavelength of 0.15418 nm. The obtained X-ray diffraction patterns were background-processed using Rigaku's powder X-ray analysis software PDXL2, followed by smoothing and peak detection. The crystallite size of the first peak of calcium titanate CaTiO3 that appeared in the diffraction angle 2θ range of 22.00° to 24.00° was calculated and taken as the crystallite size of the powder.

[0047] [Roundness] Circularity was evaluated using SEM images of primary particles of calcium titanium complex oxide. Specifically, images obtained at a magnification of 3000x using a JEOL scanning electron microscope JSM-7200F were used, and the circularity was calculated using the image analysis software ImageJ. The particle area was defined as S(m²). 2 ), if the perimeter of the particle is l(m), the circularity r is expressed by the following formula: r = 4π × S / l 2 .

[0048] [D 50 [Diameter and SD value] D 50 The diameter and particle size distribution (SD value) were evaluated using a Microtrac® MT3300EX II laser diffraction scattering particle size analyzer manufactured by Microtrac-Bell, in accordance with the method compliant with JIS Z 8825:2022. Ion-exchanged water was used as the dispersion medium. After adding an appropriate amount of powder to the ultrasonic dispersion tank of an automatic sample circulator attached to the measuring device, ultrasonic dispersion was performed at an output of 40W for 60s. For each measurement parameter, the refractive index of the ion-exchanged water was set to 1.33, the light transmittance of the target particles was set to reflectance, and the measurement time was set to 60s. In the cumulative particle size distribution, the particle diameter corresponding to the median value based on volume was set to D 50The diameter was defined as X. In addition, the particle size corresponding to 16% in the volume-based cumulative particle size distribution was defined as X. 16 In the μm, volume-based cumulative particle size distribution, the particle size corresponding to 84% is X 84 If we consider the unit to be μm, the SD value W(μm) is expressed by the following formula: W=(X 84 -X 16 ) / 2.

[0049] [Powder L* value] 10.0 g of powder was placed into an aluminum ring (radius 20 mm, thickness 5 mm) fitted with a jig, and a compacted powder was formed by applying a pressure of 189 kN (150 MPa) using a SHIMADZU MP-35 briquette machine (hereinafter referred to as "briquette machine"). The L* value of the compacted powder was measured using the reflection mode with a Suga Test Instruments SM-T45 color computer (hereinafter referred to as "color computer").

[0050] [Apparent Density] The apparent density was evaluated using an apparent density meter in accordance with JIS K 5101-12-1:2004. The cup used to receive the powder was 30 cm. 3 The following was used. If the weight of the powder in the cup is x g, the apparent density a (g / mL) is expressed by the following formula: a = x / 30

[0051] [Powder density] Approximately 8 mm of powder was placed in an aluminum ring (radius 20 mm, thickness 5 mm) fitted with a jig, and a compact was formed by applying a pressure of 63 kN (50 MPa) using a briquetting machine. The thickness of the compact was measured using calipers, and the compact density was calculated from the volume and mass of the compact. The amount of powder placed in the aluminum ring was x g, the thickness of the compact was y mm, and the area of ​​the aluminum ring was z cm. 2 Therefore, the compacted flour density a (g / cm³) 3 ) can be expressed by the following formula.

[0052] a = x / (y / 10 × z). [Amount of oil absorbed by boiled flaxseed] 5.0 g of powder was piled high on a glass plate. One drop of boiled linseed oil, which had been held in a microburette beforehand, was dropped into the center of the sample, and the entire sample was kneaded uniformly with a spatula. The process of dropping one or two drops of boiled linseed oil at a time and kneading was repeated until the entire sample became a hard, uniform, putty-like mass. If the amount of boiled linseed oil used is x g, the amount of boiled linseed oil absorbed, a (g / 100g), is expressed by the following formula: a = 100 × x / 5.0.

[0053] [Preparation of resin compositions for evaluation] 856.4 g / kg of cresol novolac EOCN-1020-70 epoxy resin manufactured by Nippon Kayaku, 142.7 g / kg of jER Cure® 170 curing agent manufactured by Mitsubishi Chemical, and 0.9 g / kg of U-CAT SA841 curing accelerator manufactured by Sunapro were weighed and mixed in a mixer to obtain a resin mixture. Calcium titanium complex oxide powder was added to the resin mixture so that the volume fraction of the powder was 215.7 mL / L to obtain a resin-powder mixture. 300 g of the resin-powder mixture was heated to 100°C and kneaded for 20 minutes in a Moriyama Seisakusho DSO.5-3MHB-E kneader to obtain a resin composition for evaluation.

[0054] [L* value of resin composition] The L* values ​​of the evaluation resin compositions were measured using a color computer in reflection mode.

[0055] [Melt Flow Rate (MFR)] The evaluation resin composition was placed in a melt indexer manufactured by Nippon Dynisco, heated at 100°C for 2 minutes to melt, and the mass discharged in 20 seconds under a load of 2.16 kg was measured to calculate the melt flow rate. The approximate mass of the evaluation resin composition to be placed in the indexer is 10g to 15g. If the mass discharged in 20 seconds is xg, the melt flow rate a (g / 10min) is expressed by the following formula: a = 30 × x

[0056] The present invention will be further described in detail by the following examples and comparative examples. The following examples are provided for illustrative purposes only and do not limit the scope of the invention. In the stirring operations described in the examples and comparative examples, the rotation speed is appropriately adjusted to ensure uniform mixing of the liquid and to prevent splashing, taking into consideration properties related to the behavior of the liquid during stirring, such as the liquid volume, viscosity, and container shape. Furthermore, in cases where the same effect can be obtained using any commercially available product from any company, such as hydrochloric acid, the names of the manufacturers and distributors have been omitted.

[0057] [Example of titanium source slurry production] Metatitanic acid with a micelle diameter of 40 nm, obtained by the sulfuric acid method, was subjected to iron removal and bleaching. Sodium hydroxide solution was then added to adjust the pH to 9.0 for desulfurization, followed by the addition of hydrochloric acid to neutralize the pH to 6.0. The mixture was then filtered and washed with deionized water to obtain a metatitanic acid cake with a sulfur content of 9.3 g / kg (SO3 equivalent). Water was added to the washed cake to form a slurry with a Ti concentration of 2.3 mol / L. Hydrochloric acid was then added to adjust the pH to 1.2 for osmotic treatment. The resulting slurry was used as the titanium source slurry.

[0058] [Example 1] A titanium source slurry containing 4.00 kg of TiO2 was mixed with 80 g of polyvinyl alcohol JP-05 (hereinafter referred to as "PVA") manufactured by Nippon Bi-Poval to adjust the solid content concentration to 110 g / L. A sodium hydroxide aqueous solution was added to adjust the pH to 6.5, and the mixture was stirred for 3.5 hours. The slurry was spray-dried using an OC-16 spray dryer manufactured by Okawara Chemical Machinery Co., Ltd., and then granulated. Spray drying was performed using a two-fluid nozzle, with an inlet temperature of 250°C and an outlet temperature of 105°C, while appropriately adjusting the slurry supply rate within the range of 120 mL / min to 300 mL / min.

[0059] The granular material obtained from the spray-dried spherical titanium source was calcined at 775°C for 0.5 hours in an atmospheric environment (primary calcination). After the calcined material was rehydrated by adding deionized water to achieve a solid content concentration of 125 g / L, Marukyo Lime's food-grade slaked lime (hereinafter referred to as "slaked lime") was added to achieve a Ca / Ti molar ratio of 1.10, and the mixture was stirred for 3.5 hours.

[0060] The slurry was diluted to a solid content of 50 g / L, and 0.05 g / kg of Hymo Lock® SS-120 manufactured by Hymo was added as a flocculant. The mixture was allowed to settle and filtered. The filtered cake was dried at 120°C and calcined at 1030°C for 2.0 hours under an air atmosphere (secondary calcination). The calcined material was crushed using a Sample Mill TASM-1 manufactured by Tokyo Atomizer Manufacturing Co., Ltd. (hereinafter referred to as "Sample Mill") with a screen diameter of 2.0 mm.

[0061] The obtained calcium titanium complex oxide powder was rehydrated with water to a solid content concentration of 125 g / L, then hydrochloric acid was added until the pH reached 5.0, and the mixture was stirred for 1 hour (acid treatment step). After that, it was filtered using a Nutsche filter and washed with deionized water. Washing was continued until the electrical conductivity of the filtrate was 100 μS / cm or less. After washing was completed, it was dried in the air at 120°C, and crushed using a sample mill with a screen diameter of 2.0 mm to obtain a calcium titanium complex oxide powder. The obtained powder is referred to as Powder 1. The manufacturing conditions for Powder 1 are shown in Table 1, and its various properties are shown in Table 2.

[0062] [Example 2] To powder 1, 9 g / kg of XIAMETER® OFS-6040 Silane, manufactured by Dow-Toray and containing 3-glycidoxypropyltrimethoxysilane, was added as a surface treatment agent. The mixture was then mixed for 8 minutes at a peripheral speed of 8 m / s using a Nippon Coke Industries FM-10B mixer to perform surface treatment. The surface-treated product was heat-treated in air at 90°C for 4 hours, crushed using a sample mill with a screen diameter of 2.0 mm, and a powder consisting of calcium titanium complex oxide was obtained. The obtained powder is referred to as powder 2. The various properties of powder 2 are shown in Table 2.

[0063] [Example 3] A powder consisting of calcium titanium complex oxide was obtained using the same procedure as in Example 1, except that a secondary calcination was performed at 1150°C for 3.0 hours and the acid treatment step was omitted. The obtained powder was designated as Powder 3. The various properties of Powder 3 are shown in Table 2. Figure 1 shows an SEM image of Powder 3 (magnification 20,000x).

[0064] [Example 4] A powder consisting of calcium titanium complex oxide was obtained using the same procedure as in Example 3, except that the Ca / Ti molar ratio was set to 1.05. The obtained powder was designated as powder 4. The various properties of powder 4 are shown in Table 2.

[0065] [Example 5] Powder 4 was rehydrated with water to form a slurry with a solid content of 125 g / L, then hydrochloric acid was added until the pH reached 5.0, and the mixture was stirred for 1 hour (acid treatment step). After that, it was filtered using a Nutsche filter and washed with deionized water. Washing was continued until the electrical conductivity of the filtrate was 100 μS / cm or less. After washing was completed, it was dried in the air at 120°C and crushed using a sample mill with a screen diameter of 2.0 mm to obtain a powder consisting of calcium titanium complex oxide. The obtained powder is referred to as powder 5. Various properties of powder 5 are shown in Table 2. Figure 2 shows an SEM image of powder 5 (magnification 3000x).

[0066] [Example 6] Except for omitting the primary firing step of firing at 775°C for 0.5 hours, the powder obtained using the same procedure as in Example 4 was further processed using the same procedure as in Example 5 to obtain powder 6. The various properties of powder 6 are shown in Table 2. The cumulative particle size distribution of powder 6 is shown in Figure 3, and the X-ray diffraction pattern is shown in Figure 4.

[0067] [Example 7] Powder 7, consisting of calcium titanium complex oxide, was obtained using the same procedure as in Example 1, except that the primary firing temperature was 850°C and the secondary firing was performed at 1170°C for 10.0 hours. The various properties of powder 7 are shown in Table 2.

[0068] [Example 8] Powder 8, consisting of calcium titanium complex oxide, was obtained using the same procedure as in Example 1, except that the primary firing temperature was 850°C and the secondary firing was performed at 1190°C for 10.0 hours. The various properties of powder 8 are shown in Table 2.

[0069] [Comparative example A] Slaked lime was added to a titanium source slurry containing 4.00 kg of TiO2 so that the Ca / Ti molar ratio was 1.10. Additionally, 80 g of PVA was added to bring the solid content concentration to 110 g / L, and the slurry was stirred for 2 hours. This slurry was then spray-dried and granulated using the same apparatus and nozzle as in Example 1, within the same inlet and outlet temperatures and feed rate range.

[0070] The obtained spray-dried material was calcined at 850°C for 3.0 hours in an atmospheric environment to obtain powder A. Powder A had numerous cavities of about 1.0 μm on the particle surface and did not maintain a spherical shape. Various properties of powder A are shown in Table 2. Powder A had low particle roundness and a large amount of boiled sugar oil absorbed.

[0071] [Comparative example B] A powder consisting of calcium titanium complex oxide was obtained using the same procedure as in Example 1, except that both the primary and secondary calcination were performed at 850°C for 0.5 hours. The obtained powder was designated as powder B. The various properties of powder B are shown in Table 2.

[0072] [Comparative example C] 3.76 mol of titanium dioxide powder with an average particle size of 0.18 μm and 3.58 mol of calcium carbonate were mixed in a vibratory mill for 2 hours. The mixed powder was calcined at 1200°C for 2 hours in an air atmosphere, and the calcined material was crushed using a sample mill with a screen diameter of 2.0 mm.

[0073] Next, a mixture of liquefied natural gas and pure oxygen was supplied to a gas burner to form a high-temperature flame. The pulverized material was then dispersed and supplied into the flame, which reached a maximum temperature of 2400°C, and sintered to form spheres. Although it was difficult to accurately measure the time each individual particle was in the flame, it was estimated to be several seconds. The resulting powder is referred to as powder C. The various properties of powder C are shown in Table 2.

[0074] [Table 1]

[0075] [Table 2]

[0076] Table 1 shows the manufacturing conditions for the powders of the examples and comparative examples, and Table 2 shows the properties of the powders of the examples and comparative examples. As shown in Table 2, the titanium source was subjected to spray drying and granulation, then mixed with the calcium source, and fired at a temperature of 1000°C to 1800°C, resulting in a crystallite size of 60.0 nm to 98.0 nm, a circularity of 0.88 or higher, and D 50 Powders consisting of calcium titanium complex oxide with a diameter of 2.0 μm to 15.0 μm and a powder L* value of 88.0 or less were obtained. The L* values ​​of the resin compositions to which these powders were added were all 78.0 or less. Furthermore, the oil absorption amount was 25.0 g / 100 g or less, and the melt flow rate was 150 g / 10 min or more. On the other hand, powder C, which was spheroidized in a flame at a very high temperature of 2400°C, had a large L* value, while powders A and B, whose secondary firing temperature was less than 1000°C, had small crystallite sizes and large L* values ​​and oil absorption amounts.

[0077] Furthermore, as shown in the SEM image in Figure 1 (magnification 20,000x), countless irregularities were observed on the surface of the particles constituting the powder obtained in the examples. However, as shown in the SEM image in Figure 2 (magnification 3,000x), the particle shape was spherical. Also, as shown in the cumulative particle size distribution diagram in Figure 3, the particle size distribution of the powder obtained in the examples was narrow, and no particles with a diameter of 1 μm or less were included. Moreover, as shown in the X-ray diffraction pattern in Figure 4, no peaks originating from the raw materials or other impurities were observed in the X-ray diffraction measurement.

[0078] As described above, the crystallite size of the present invention is 60.0 nm or more and 98.0 nm or less, and the circularity is 0.88 or more, D50 The calcium titanium complex oxide powder, having a diameter of 2.0 μm to 15.0 μm and a powder L* value of 88.0 or less, exhibits an appropriate apparent density, low oil absorption, and can maintain a high melt flow rate of the resin composition when added to a resin, while also keeping the L* value of the resin composition low. When used as an inorganic filler in resin compositions, such as those used in semiconductor resin encapsulants, the calcium titanium complex oxide powder of the present invention does not impair the fluidity of the resin composition and can reduce the amount of colorant required to make the resin composition black. Therefore, the powder of the present invention can increase the filling rate of the resin.

[0079] The calcium titanium complex oxide powder of the present invention is not only useful in solving the problems of the present invention, but is also considered useful in various fields. Furthermore, it is believed that by applying the method for producing a powder made of calcium titanium complex oxide, which includes a granulation step by spray drying of the titanium source according to the present invention, to other titanate compounds such as strontium titanium complex oxide and magnesium titanium complex oxide, it is possible to synthesize a powder made of spherical titanates.

Claims

1. CaTiO2 appears in X-ray diffraction measurements where the diffraction angle 2θ is in the range of 22.00° to 24.00°. ３ The crystallite size at the crystal peak is in the range of 60.0 nm to 98.0 nm, and the circularity determined from scanning electron microscope images of the particles constituting the powder is 0.88 or higher, D ５０ A powder made of calcium titanium complex oxide, having a diameter in the range of 2.0 μm to 15.0 μm and an L* value of 88.0 or less.

2. A powder comprising calcium titanium complex oxide according to claim 1, having an apparent density in the range of 0.85 g / mL or more and 1.45 g / mL or less.

3. A powder made of calcium titanium complex oxide according to claim 1 or 2, wherein the amount of boiled linseed oil absorbed is 25.0 g / 100 g or less.

4. A powder comprising calcium titanium complex oxide according to claim 1 or 2, wherein the L* value of the evaluation resin composition obtained by using the powder comprising calcium titanium complex oxide and preparing the evaluation resin composition according to the method described in the examples is 78.0 or less.

5. A powder made of calcium titanium complex oxide according to claim 1 or 2, wherein the melt flow rate of the evaluation resin composition is 150 g / 10 min or more when an evaluation resin composition is produced using the powder made of calcium titanium complex oxide according to the method described in the examples.

6. A process of subjecting a titanium source to spray drying. A step of mixing the spray-dried titanium source obtained with a calcium source, and The process of firing the resulting mixture at a temperature of 1000°C to 1800°C. A method for producing a powder consisting of calcium titanium complex oxide, including [the specified substance].

7. A method for producing a powder made of calcium titanium complex oxide according to claim 6, wherein the titanium source is metatitanic acid.

8. A resin composition comprising a powder made of calcium titanium complex oxide according to claim 1 or 2.

9. A sealing material comprising a powder made of calcium titanium complex oxide as described in claim 1 or 2.

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