Particulate material and method for producing same, slurry composition, and resin composition

Abstract

In view of the above circumstances, the present invention addresses the problem of providing a particulate material which is composed of thin plate-like silica different from conventional ones and has low cohesiveness. A particulate material according to the present invention has a D99 / mode diameter of at most 10 and is a plate-like body made of silica, wherein the ratio of the particle diameter of the long side in the spreading direction to the thickness is 5-50. Since the particulate material has excellent dispersibility even after the silica is formed into a thin plate shape, it is easy to control the orientation direction when the particulate material is dispersed in a resin composition, and also possible to make the thermal expansion coefficient of the obtained resin composition exhibit anisotropy as designed. As a result, an effect of significantly reducing the thermal expansion coefficient in the orientation direction can be exhibited.

Description

Particle material and method for producing the same, slurry composition, resin composition

[0001] This invention relates to particulate materials, methods for producing the same, slurry compositions, and resin compositions.

[0002] Electronic materials consisting of resin compositions in which fillers are dispersed in resin are widely used as packaging materials such as encapsulants for electronic elements like semiconductors, and as materials for electronic circuit boards. Resin compositions in which fillers are dispersed in resin material have improved physical properties compared to resin material alone. In recent years, electronic elements and their packaging, as well as wiring in electronic devices, have become miniaturized, and the amount of heat generated per unit volume has increased, so the performance required of electronic materials such as encapsulants has also increased. For this reason, there is a need for electronic material fillers with properties different from those of conventional fillers.

[0003] For example, spherical silica has conventionally been used as a filler for electronic materials, but the amount of spherical silica used to fill these materials has been continuously increased to reduce the coefficient of thermal expansion. As a result, it has become difficult to achieve both increased filler content and desirable properties of the resin composition, such as viscosity characteristics. Furthermore, while the development of materials with negative coefficients of thermal expansion, such as zirconium tungstate, is underway, there are challenges such as the fact that the expected reduction in the coefficient of thermal expansion may not be observed when incorporated into a resin composition, that these materials are expensive and have supply stability concerns due to the presence of rare elements, and that their relatively high dielectric constant contradicts the trend towards lower dielectric constants in semiconductor materials.

[0004] Japanese Patent Publication No. 4916768, Japanese Unexamined Patent Publication No. 2023-97431

[0005] Therefore, the inventors focused on thin-plate silica and found that thin-plate silica has desirable properties as a filler for electronic materials. Furthermore, they found that by controlling the orientation direction of the silica in a resin composition after making it into a thin plate, the thermal expansion coefficient of the resulting resin composition exhibits anisotropy and shows a significant reduction in the thermal expansion coefficient in the orientation direction. Thin-plate silica for applications other than electronic materials is disclosed in Patent Documents 1 and 2.

[0006] However, thin silica sheets have high cohesiveness, and the aggregated silica sheets do not disperse sufficiently in resin materials as they are. To improve dispersibility, a crushing and dispersion process is required, which presents challenges such as equipment wear and performance degradation due to particle breakage.

[0007] In view of the above circumstances, the present invention aims to solve the problem of providing a particle material made of thin, plate-shaped silica, which is different from conventional particle materials, and a method for producing the same.

[0008] (1) The particle material of the present invention that solves the above problems has a D99 / mode diameter of 10 or less in the particle size distribution measured by the following method, and is a plate-like material made of silica with a (particle diameter of the long side in the spreading direction) / (thickness) of 5 to 50.

[0009] Because silica is a particulate material with excellent dispersibility and a thin plate-like shape, it is easy to control the orientation direction when dispersed in a resin composition, and the thermal expansion coefficient of the resulting resin composition can be made to exhibit the anisotropy designed for it. Therefore, a significant reduction in the thermal expansion coefficient can be observed in the orientation direction. (Measurement of particle size distribution) The particle size distribution can be measured on a volume basis using a laser diffraction / scattering particle size distribution analyzer. A powdered sample is added to a flow cell through which a dispersion medium is circulated, and the volume-based particle size distribution is measured without performing dispersion treatment such as ultrasound.

[0010] Water is used as the dispersion medium during measurement, but methyl ethyl ketone is used for samples that are water-repellent due to surface modification or other reasons. Note that "measurement without performing dispersion treatment such as ultrasound" means simply circulating the dispersion liquid within the flow cell without any other operation to disperse the particulate material into the dispersion medium. For example, this means using the Shimadzu SALD-7500nano laser diffraction / scattering particle size distribution analyzer and measuring with only circulation using the optional flow cell.

[0011] The particle material disclosed in (1) above may have one or more of the following components added: (2), (3), (4), and (5). If component (3) is added, component (4) may also be added. (2) Mode diameter is 1 μm or more and 20 μm or less, D99 is 50 μm or less, thickness is 0.1 μm or more and 2 μm or less, specific surface area is 20 m ２ (1) The amount is less than or equal to / g. (3) Furthermore, the particle material comprises 0.5% by mass or more and 95% by mass or less of a second particle material composed of an inorganic material with a volume average particle size of 0.01 μm or more and 20 μm or less, based on the total mass. (4) The second particle material contains 0.5% or more of a spacer particle material having a sphericity of 0.8 or more, based on the mass of the second particle material. (5) The particle material according to claims 1 to 4, which is surface-treated with a surface treatment agent. (6) As a result of the present inventors' diligent research in order to solve the above problems, the following findings were obtained. First, when the cause of aggregation during drying was investigated, it was found that during the drying process, when the liquid water contained in the manufacturing process evaporates, bonding occurs between adjacent particles due to surface tension. Therefore, it was found that aggregation can be suppressed by replacing some or all of the liquid water present during the drying process with an organic solvent with low surface tension, and the following invention was completed.

[0012] In other words, the method for producing the particle material of the present invention that solves the above problems is a method for producing the particle material of the present invention as described above, and is based on the general formula (1): M ２ O・xSiO ２ ・yH ２The method comprises: a layered silica compound preparation step of preparing a layered silica compound represented by O (where M is an alkali metal); an acid treatment step of treating the layered silica compound with an acidic aqueous solution to obtain a composition in which the content of M is reduced; and a drying step of removing the water contained in the composition obtained in the acid treatment step to bring it to a dry state, wherein the drying step is performed while replacing the water contained in the composition with an organic solvent that is miscible with water, and / or after replacing the water contained in the composition with the organic solvent. (7) A second method for producing a particle material of the present invention that solves the above problems is a method for producing a particle material having the components of (4) described above, wherein the general formula (1): M ２ O・xSiO ２ ・yH ２ The method comprises: a layered silicate compound preparation step of preparing a layered silicate compound represented by O (where M is an alkali metal); an acid treatment step of treating the layered silicate compound with an acidic aqueous solution to obtain a composition with a reduced M content; a drying step of removing the water contained in the composition obtained in the acid treatment step to bring it to a dry state; and a step of adding the spacer particle material before the drying step is completed.

[0013] The method for producing the particle material of the present invention may include the components described in (8) below. (8) The drying step is performed while replacing the water contained in the composition with an organic solvent miscible with water, and / or after replacing the water contained in the composition with the organic solvent. (9) The slurry composition of the present invention that solves the above problems comprises the particle material of the present invention described above and an organic solvent that disperses the particle material. (10) The resin composition of the present invention that solves the above problems comprises the particle material of the present invention described above and a resin material that disperses the particle material.

[0014] The particle material, its manufacturing method, slurry composition, and resin composition of the present invention will be described in detail below based on embodiments. The numerical range "x to y" described herein includes the lower limit x and the upper limit y. A new numerical range can be constructed by arbitrarily combining these upper and lower limits, as well as the numerical values ​​listed in the specification or examples. The new numerical range may also be a range that does not include one or both of the upper and lower limits. For example, a range greater than x can be adopted, or a range less than y can be adopted. Furthermore, numerical values ​​arbitrarily selected from any of the above numerical ranges can be used as the upper and lower limits of the new numerical range. (Particle Material) The particle material of this embodiment is particularly suitable as a filler for electronic materials such as semiconductor encapsulants, underfills, and substrate materials, but it can also be used in applications where ordinary silica-based particle materials can be used, such as cosmetics, paints, and rubber fillers.

[0015] The particle material of this embodiment includes a thin plate-like material. The thin plate-like material has a ratio of (particle diameter on the long side in the spreading direction) / (thickness) of 5 to 50. Here, the lower limit of (particle diameter on the long side in the spreading direction) / (thickness) can be 7, 8, 10, or 12, and the upper limit can be 45, 40, 35, or 30. These upper and lower limits can be combined arbitrarily.

[0016] The particle material in this embodiment has a D99 / mode diameter of 10 or less, with examples of upper limits being 8, 7, 6, 5, 4, and 3. Here, D99 is the particle size at which the cumulative volume accounts for 99% when the particles are arranged from smallest to largest. Preferably, the upper limits of D99 are 50 μm, 45 μm, 40 μm, 35 μm, and 30 μm. The conditions for measuring D99 and mode diameter are to use a laser diffraction particle size distribution analyzer (Shimadzu Corporation, model number: SALD-7500nano) and calculate the particle size distribution using a flow cell. The dispersion medium is water, and the particle material is added directly to the flow cell without any dispersion treatment such as ultrasound. If the surface of the particle material is highly water-repellent and cannot be dispersed in water, methyl ethyl ketone is used as the dispersion medium for measurement.

[0017] In the filler for electronic materials of the present embodiment, it is particularly preferable that the thickness of the sheet-shaped material is 0.1 μm to 3 μm. For the thickness of the sheet-shaped material, it is preferable that the lower limit values are 0.12 μm, 0.14 μm, 0.15 μm, and the upper limit values are 1.5 μm, 1 μm, 0.8 μm. These upper limit values and lower limit values can be combined arbitrarily. The thickness of the sheet-shaped material is a value measured by arithmetically averaging the thicknesses of 50 or more particles observed at a magnification of 2000 times using a scanning electron microscope (SEM).

[0018] In addition, it is preferable that the particle diameter of the long side in the spreading direction is 1 to 20 μm. For the particle diameter of the sheet-shaped material in the spreading direction, it is preferable that the lower limit values are 1.5 μm, 2 μm, 3 μm, and the upper limit values are 17 μm, 15 μm, 10 μm. These upper limit values and lower limit values can be combined arbitrarily.

[0019] The particle diameter of the long side in the spreading direction of the sheet-shaped material is a value measured by arithmetically averaging the thicknesses of 50 or more particles observed at a magnification of 2000 times using a scanning electron microscope (SEM). When measuring the particle diameter of the long side by directly measuring the filler for electronic materials, the filler for electronic materials is directly photographed by SEM, and for each particle represented two-dimensionally on the photograph, the longest portion is taken as the particle diameter of the long side.

[0020] The specific surface area of the particulate material of the present embodiment is 20 m ２ / g or less as a value measured by the BET method using nitrogen gas, and as the lower limit, 18 m ２ / g, 16 m ２ / g, 14 m ２ / g can be exemplified.

[0021] It is preferable that part or all of the sheet-shaped material is composed of an amorphous material. Specifically, the crystallinity of silica constituting the sheet-shaped material is preferably 50% or less, more preferably 30% or less, still more preferably 20% or less, still more preferably 10% or less, still more preferably 5% or less, and particularly preferably 0%.

[0022] Crystallinity is calculated from the XRD spectrum. The peak area of ​​the crystalline peak in the XRD spectrum is calculated based on the sum of the area of ​​the halo pattern derived from the amorphous material and the peak area. If no crystalline peaks are observed, a crystallinity of 0% means that the area of ​​the crystalline peak in the XRD spectrum is less than 1% (more preferably less than 0.5%).

[0023] The thin plate-like material consists of silica, and while a silica content of 50% by mass or more per particle is sufficient, lower limits of 60%, 70%, 80%, 90%, 95%, 99%, and 100% can be adopted. Other materials that can be included include inorganic oxides such as alumina, titania, magnesia, and zirconia, as well as metal nitrides.

[0024] The particle material of this embodiment is preferably surface-treated with a surface treatment agent. The surface treatment agent is one or more compounds selected from silane compounds and silazane compounds.

[0025] Examples of silane compounds include compounds having an SiH structure or SiOR (where R is alkyl), in which organic functional groups such as alkyl groups with about 1 to 18 carbon atoms, alkenyl groups with about 8 carbon atoms, amino groups, phenyl groups, epoxy groups, acrylic groups, methacrylic groups, styryl groups, aminophenyl groups, and isocyanate groups are directly connected to the Si atom, or are connected with a divalent functional group such as an alkylene group as a spacer. Examples of silazane compounds include hexamethyldisilazane.

[0026] The amount of surface treatment agent to react with the thin plate-like material is not particularly limited. For example, if we define 100% as the amount sufficient to bond with all the reactive groups, such as OH groups, present on the surface of the thin plate-like material, then examples of amounts such as 30%, 50%, 75%, 100%, 150%, and 200% can be used.

[0027] Furthermore, the particle material of this embodiment is preferably such that the electrical conductivity of the extracted water measured by the following method is 50 μS / cm or less. Examples of upper limits for the electrical conductivity of the extracted water include 45 μS / cm, 30 μS / cm, and 20 μS / cm. • Method for measuring the electrical conductivity of the extracted water 3.5 g of the sample and 35 mL of deionized water are weighed into a 50 mL centrifuge tube, shaken for 30 minutes in a shaker, and then the supernatant liquid obtained by settling the sample in a centrifuge is measured with an EC meter. The value obtained is taken as the electrical conductivity of the extracted water. A shaker model number: SA300, manufactured by Yamato Scientific, can be used.

[0028] The particle material of this embodiment may consist solely of a thin plate-like material, or it may contain other particle materials (second particle material). For example, the second particle material may be a mixture of spherical silica, amorphous silica, alumina particle material, titania, magnesia, etc. It is preferable that the second particle material is contained in an amount of 0.5% by mass or more and 95% by mass or less, based on the total mass. Possible lower limits for the content of the second particle material include 1.0% by mass, 1.5% by mass, 2.0% by mass, 2.5% by mass, 3.0% by mass, 3.5% by mass, 4.0% by mass, 4.5% by mass, 5.0% by mass, 10% by mass, 20% by mass, 30% by mass, and 40% by mass. The lower limit for the content of the thin plate-like material can be 5%, 10%, 20%, 30%, 40%, 50%, and 60% by mass, based on the total mass of the particle material. It is also preferable that the second particle material is surface-treated with the surface treatment agent described above.

[0029] Furthermore, it is preferable that the second particle material has a particle diameter smaller than the particle diameter of the longer side in the spreading direction of the thin plate-like material.

[0030] The particle size of the second particle material is preferably about 0.01 μm to 20 μm, more preferably about 0.05 μm to 15 μm, and even more preferably about 0.1 μm to 10 μm.

[0031] As the second particle material, a spacer particle material is used or partially included that acts like a roller, sandwiched between thin plate-shaped particle materials, allowing relative movement to be facilitated without aggregation between the thin plate-shaped particle materials. The spacer particle material is preferably highly spherical, and for example, the lower limit of sphericity can be 0.8, 0.85, 0.9, 0.95, or 0.99. The content of the spacer particle material can be 0.5% or more and 100% or less based on the total mass of the second particle material. Furthermore, the content of the spacer particle material can be 0.5% by mass or more based on the mass of the thin plate-shaped material, and can also be 1% by mass or more, 1.5% by mass or more, 2.0% by mass or more, 2.5% by mass or more, 3.0% by mass or more, 3.5% by mass or more, 4.0% by mass or more, 4.5% by mass or more, or 5.0% by mass or more. (Slurry composition) The slurry composition of this embodiment consists of the particle material of this embodiment described above and a dispersion medium for dispersing the particle material. In addition to these, other materials can be mixed in as needed. The slurry composition of this embodiment can be applied as is or mixed with some resin material to semiconductor encapsulants, substrate materials, underfill materials for semiconductor devices, build-up film materials, etc.

[0032] While there are no specific limitations on the content of particulate material, it can be approximately 20% to 80% by mass. Lower limits can be set at 30%, 40%, 50%, or 60%.

[0033] The dispersion medium is not particularly limited as long as it is a liquid. Examples include ketones such as methyl ethyl ketone and methyl isobutyl ketone, aromatic hydrocarbon solvents such as toluene and xylene, organic solvents such as methanol, ethanol and isopropanol, water, and resin material precursors (monomers, prepolymers, etc.: resin precursors). The content ratio of the filler is not particularly limited, but it is preferable to increase it as long as the fluidity of the slurry is maintained. Other materials are not particularly limited, but various additives can be included. (Resin composition) The resin composition of this embodiment consists of the particle material of this embodiment described above and a resin material that disperses the particle material. Other materials can be mixed in as needed. The electronic material of this embodiment can be applied to semiconductor encapsulants, substrate materials, underfill materials for semiconductor elements, build-up film materials, etc., and may be used in combination with some electronic component (including electronic components in the usual sense, such as semiconductor elements, as well as components that work in combination with ordinary electronic components, such as electrical wiring including via holes and through holes, to operate those electronic components).

[0034] While there are no specific limitations on the content of particulate material, it can be approximately 10% to 80% by mass. Lower limits can be set at 20%, 30%, 40%, 50%, etc.

[0035] The resin material is not particularly limited, but may be in liquid or solid form, and may also include precursors (such as monomers) before polymerization. When the resin material is liquid, the resin composition of this embodiment is also the slurry composition of this embodiment. Examples of resin materials and their precursors include epoxy resins, silicone resins, and acrylic resins. Other materials are not particularly limited, but may include various additives.

[0036] In the resin composition of the present embodiment, it is preferable that the particulate material is dispersed to have anisotropy in the resin material. Having anisotropy means that the spreading direction of the sheet-like material (the direction orthogonal to the thickness direction) is oriented (aligned in a certain direction). For electronic materials, the coefficient of linear expansion in the direction in which the sheet-like material is oriented can be smaller compared to other directions. Here, whether the directions are aligned in a certain direction, and if so, what the aligned direction (orientation) is, is evaluated as follows.

[0037] First, a cross-section obtained by cutting the resin composition is observed with a scanning electron microscope (SEM), and the angle of the orientation direction is statistically analyzed from the directions that the major axes of a plurality of particles appearing on the cross-section face. From the analysis results, the degree of orientation (the degree from completely random directions to completely aligned in one direction) is calculated.

[0038] By obtaining the degree of orientation and the orientation angle in a plurality of cross-sections in different directions in this way, a three-dimensional orientation direction in the resin composition can be obtained.

[0039] Note that the direction in which it is desired to increase or decrease the thermal expansion coefficient and thermal conductivity of the resin composition varies depending on the relative positional relationship with the electronic components to be combined. Therefore, the orientation direction of the particulate material can also be changed according to the outer shape of the electronic component.

[0040] For the resin composition, the coefficient of linear expansion in the direction in which the sheet-like material is oriented can be smaller compared to other directions. Here, the direction in which the sheet-like material is oriented refers to a direction obtained from the average value of the directions that the direction orthogonal to the thickness direction of the sheet-like material (the spreading direction) faces. (Method for Producing Particulate Material) The method for producing the particulate material of the present embodiment is a method capable of suitably producing the above-described particulate material.

[0041] The particulate material of the present embodiment includes a layered silicate compound preparation step, an acid treatment step, a drying step, and other optional steps as necessary.

[0042] The layered silicate compound preparation step is represented by general formula (1): M ２O・xSiO ２ ・yH ２ This is a step in preparing a layered silicate compound represented by O (where M is an alkali metal). Here, M is preferably Na. Then, x can be about 4 to 20 and y can be about 5 to 10. Examples of layered silicate compounds when M is Na include makatiite (x is about 4, y is about 5), kanemite (x is about 4, y is about 7), islaite (x is about 8, y is about 10), magadiite (x is about 12, y is about 10), and kenyaite (x is about 20, y is about 10).

[0043] The layered silicate compound preparation process involves heating an aqueous sodium silicate solution to prepare the layered silicate compound. The aqueous sodium silicate solution may be made using so-called water glass as is, or it may be prepared by dissolving silica in an alkaline aqueous solution containing an alkali metal.

[0044] The silica to be dissolved in the alkaline aqueous solution is not particularly limited, but amorphous silica is preferred, and it is especially preferable to select a material with a large specific surface area, such as colloidal silica or silica gel. Furthermore, the dissolution rate can be improved by performing a grinding operation (such as using a ball mill) or heating during the dissolution process. When heating, a temperature of about 40°C to 80°C can be used. It is also possible to dissolve by heating to 100°C or higher under pressure. When heating is performed during dissolution, the layered silicate compound described in general formula (1) can be formed by hydrothermal synthesis by continuing the heating.

[0045] The heating temperature for forming the layered silicate compound is not particularly limited as long as the reaction proceeds, but a temperature of approximately 100°C to 160°C can be used. The heating time can be set to the time required for the hydrothermal synthesis to be completed, but for example, three weeks at 110°C is one example.

[0046] Examples of alkaline aqueous solutions include sodium hydroxide aqueous solution and potassium hydroxide aqueous solution. In the case of sodium hydroxide, the alkali concentration is preferably such that the silica / sodium hydroxide molar ratio is 1.7 or higher.

[0047] The acid treatment process involves treating the layered silicate compound with an acidic aqueous solution to replace the alkali metal M contained in the layered silicate compound with hydrogen.

[0048] The acid treatment process involves immersing the layered silicate compound in an acidic aqueous solution prepared to a pH of ≤ 4.0. By lowering the pH to 4.0 or below, sufficient cation exchange can be carried out between alkali metal ions (such as sodium ions) in the layered silicate compound and hydrogen ions in the acidic aqueous solution.

[0049] Furthermore, it is preferable that the temperature of the acidic aqueous solution in the acid treatment process be relatively high; for example, setting it to 20°C or higher allows for sufficient cation exchange. Regarding the acid treatment time, in principle, it is shorter when the acid treatment temperature is high and longer when the acid treatment temperature is low, but it is not particularly limited.

[0050] The acid treatment step is preferably carried out by immersion in an acidic aqueous solution prepared to have a pH of 0.0 to 3.0 and a temperature of 20 to 95°C, with a pH of 1.0 to 3.0 being more preferable and a temperature of 40 to 80°C being even more preferable. Within the aforementioned pH and temperature ranges, the cation exchange can be carried out efficiently. The acid treatment time is preferably 5 minutes or more, more preferably 0.1 to 12 hours, and even more preferably 0.5 to 3 hours. The conditions for the acid treatment can be such that they allow for amorphous formation in combination with the amorphous formation step in (2).

[0051] In the acid treatment step, aqueous solutions of mineral acids or mineral salts such as sulfuric acid, hydrochloric acid, and nitric acid can be used as the acidic aqueous solution. However, aqueous solutions of nitric acid, hydrochloric acid, or their salts are preferred because they are volatile and can be easily removed by heating afterward.

[0052] The drying process involves removing moisture from the composition obtained in the acid treatment process to achieve a dry state. The drying process can be carried out by heating within a temperature range that does not degrade the particulate material, or by performing the drying process under reduced pressure.

[0053] The drying process is carried out either (1) while replacing the water contained in the composition with a water-miscible organic solvent, and / or after replacing the water contained in the composition with an organic solvent, or (2) while the spacer particle material is present. (1) and (2) can be combined.

[0054] Regarding (1), if the water contained in the composition is simply evaporated, the surface tension of the water will cause the adjacent particulate materials to aggregate. Therefore, the water is either replaced with another substance before drying, or the water is removed while replacing it with another substance.

[0055] Here, "other substances" refers to organic solvents that are miscible with water. Examples of preferred organic solvents include isopropyl alcohol (IPA), propylene glycol monomethyl ether (PGM), propylene glycol monomethyl ether acetate (PGMAC), and cyclohexanone. Aggregation can be suppressed by using one or more of these organic solvents as a mixed solvent. In particular, aggregation can be effectively suppressed by replacing all contact water with organic solvents.

[0056] Furthermore, as an organic solvent other than water, it is preferable to use an organic solvent that is miscible with water and evaporates simultaneously with or slowly with water (e.g., PGM, PGMAC, cyclohexanone). This is because even if contact water remains, it will evaporate first, leaving the organic solvent behind and suppressing the progression of aggregation during drying. Examples of organic solvents that evaporate slower than water include those with a boiling point above 100°C, or those that form an azeotropic mixture with water and evaporate simultaneously with water.

[0057] Regarding the amount of organic solvent added, it is preferable that the organic solvent makes up more than 30% of the total mass of the organic solvent and water. The lower limit of the amount of organic solvent added is preferably 35%, 40%, 45%, or 50%.

[0058] Drying methods include drying while stirring, or spray drying. Drying while stirring suppresses aggregation. Using a reduced pressure or vacuum atmosphere for stirring allows for effective removal of moisture and organic solvents.

[0059] Instead of stirring, the composition is sprayed into a high-temperature atmosphere, a process known as spray drying. This removes moisture and organic solvents before the particulate material can aggregate, thus suppressing aggregation. The end of the drying process is not particularly limited, but it can be determined to be the end of this process when the amount of moisture contained becomes 1.0% by mass or less, 0.5% by mass or less, or 0.3% by mass or less, based on the total mass.

[0060] Step (2) involves adding the spacer particle material described in the section on particle materials before the drying process is completed. Adding the spacer particle material while moisture is present suppresses aggregation that would otherwise occur due to surface tension generated when the moisture evaporates.

[0061] The process may include an amorphousization step after the drying step, in which the layered silica compound is heated to make it amorphous. The amorphousization step is a process of making silica amorphous. By employing the amorphousization step, the resulting particulate material can be amorphous.

[0062] The amorphization process involves heat treatment at a temperature of 100°C or higher. The temperature can be selected to achieve amorphization in combination with the acid treatment process. The heat treatment may be carried out in the presence of water vapor. However, conditions in which the water vapor condenses into liquid water are undesirable. By heating to 100°C or higher, further removal of moisture remaining even after the drying process can be advanced, and the reaction rate improves as the temperature increases. There are no particular upper limits on the heating temperature other than that the layered silicate compound does not dissolve. However, from the viewpoint of reducing manufacturing costs, a lower temperature is preferable, so an appropriate heating temperature can be set by balancing the reduction in processing time due to the increase in heating temperature with the processing cost.

[0063] The amorphization process is preferably carried out by heat treatment at a temperature of 200 to 1150°C for 1 to 10 hours, more preferably at a temperature of 400 to 800°C and for 1.5 to 3 hours. Amorphization proceeds efficiently within the above temperature range.

[0064] The drying and amorphous processes may be followed by a process to break down the slowly aggregated particle material. A classification process, such as sieving, may also be included. By employing a breaking and classification process, the particle size distribution can be adjusted to the desired level.

[0065] Furthermore, the layered silicate compound obtained in the layered silicate compound preparation step may be washed at some point before the drying step. Washing can be done with pure water or the organic solvent mentioned above. (Method for producing resin composition) The resin composition produced by the method for producing resin composition of this embodiment is used in devices such as integrated circuits and substrate materials in which semiconductor elements, wiring, and electronic elements are sealed with the resin composition. In these electronic devices, since components made of multiple materials are adjacent to each other, it is preferable that the coefficients of thermal expansion between these components are close. In addition, there is a direction in which the coefficient of thermal expansion can be reduced depending on the joint of dissimilar materials.

[0066] In the method for producing the resin composition of this embodiment, the coefficient of thermal expansion in a desired direction can be made smaller than in other directions by controlling the orientation of the particle material contained in the resin composition.

[0067] The method for producing the resin composition of this embodiment comprises a preparation step and a curing step. The preparation step is a step of preparing the resin composition by dispersing the particulate material of this embodiment in a resin material.

[0068] The curing process is a process of curing a resin composition by controlling the orientation of the particle material. Specifically, it is a process of curing the resin material after applying and / or while applying acceleration in the direction in which the thin plate-like material is to be oriented. For example, when a thin plate-like material settles in the resin composition, its spreading direction becomes parallel to the direction of acceleration, so the direction of orientation can be controlled by curing the material with the desired orientation parallel to the direction of acceleration. Examples of methods for applying acceleration include applying it by gravity or by centrifugal force.

[0069] Furthermore, the particle material can be oriented in the direction of flow by flowing a resin composition in which the particle material is dispersed in a resin material, such as through injection molding. It should be noted that when particles with anisotropic shape, such as those in the present invention, are dispersed in a resin material, at least gravity is applied as an external force, so it can be inferred that they will normally orient themselves in a certain direction at a microscopic level.

[0070] The present invention will be described in detail below with reference to examples. <Example 1> (Preparation of layered silicate compound) 100 g of sodium silicate No. 5 (manufactured by Fuji Chemical Co., Ltd.) was weighed into a 100 mL pressure-resistant container and reacted at 110 °C for 2 weeks to obtain a layered silicate compound. The obtained layered silicate compound was washed with deionized water (washing step) to obtain an aqueous dispersion of the layered silicate compound. (Acid treatment step) 200 g of 10% nitric acid aqueous solution was added to 150 g (30 g solids) of the aqueous dispersion obtained in the preparation of the layered silicate compound and stirred for 3 hours. After that, an aqueous dispersion of the hydrogen-substituted layered silicate compound was obtained by washing with deionized water. (Drying step) An equal amount of IPA as an organic solvent was added to the aqueous dispersion obtained in the acid treatment step and stirred. After that, the material was dried at 160 °C to obtain a particle material with suppressed aggregation. (Amorphization step) The particle material obtained in the drying step was heated and calcined at 800 °C for 5 hours to obtain an amorphous particle material. <Example 2> A particle material was obtained in the same manner as in Example 1, except that PGM was added instead of IPA in the drying process. <Example 3> A particle material was obtained in the same manner as in Example 1, except that PGMEA was added instead of IPA in the drying process. <Example 4> A particle material was obtained in the same manner as in Example 1, except that cyclohexanone was added instead of IPA in the drying process. <Example 5> A particle material was obtained in the same manner as in Example 1, except that instead of adding an organic solvent in the drying process, 5 parts by mass of spherical silica particles (manufactured by Admatex Co., Ltd.) with an average particle size of 0.3 μm were added as a spacer particle material (corresponding to the second particle material; the same applies hereinafter) to 100 parts by mass of layered silica compound. <Example 6> A particle material was obtained in the same manner as in Example 1, except that instead of adding an organic solvent in the drying process, 5 parts by mass of spherical silica particles (manufactured by Admatex Co., Ltd.) with an average particle size of 0.5 μm were added as a spacer particle material to 100 parts by mass of layered silica compound. <Example 7> A particle material was obtained in the same manner as in Example 1, except that instead of adding an organic solvent in the drying process, 5 parts by mass of a spherical silica particle dispersion with an average particle size of 45 nm (manufactured by Nissan Chemical Corporation) was added as a spacer particle material to 100 parts by mass of a layered silica compound.<Example 8> A particle material was obtained in the same manner as in Example 2, except that 5 parts by mass of spherical silica particles (manufactured by Admatex Co., Ltd.) with an average particle size of 0.3 μm were added as a spacer particle material to 100 parts by mass of the layered silica compound in the drying step. <Example 9> A particle material was obtained in the same manner as in Example 2, except that 5 parts by mass of spherical silica particles (manufactured by Admatex Co., Ltd.) with an average particle size of 0.5 μm were added as a spacer particle material to 100 parts by mass of the layered silica compound in the drying step. <Example 10> A particle material was obtained in the same manner as in Example 2, except that 5 parts by mass of a dispersion of spherical silica particles (manufactured by Nissan Chemical Corporation) with an average particle size of 45 nm were added as a spacer particle material to 100 parts by mass of the layered silica compound in the drying step. <Comparative Example 1> (Layered silica compound preparation step) 100 g of sodium silicate No. 5 (manufactured by Fuji Chemical Co., Ltd.) was weighed into a 100 mL pressure-resistant container and reacted at 110 °C for 2 weeks to obtain a layered silica compound. The obtained layered silicate compound was washed with deionized water (washing step) to obtain an aqueous dispersion of the layered silicate compound. (Acid treatment step) 150 g (30 g solids) of the aqueous dispersion of the layered silicate compound obtained in the layered silicate compound preparation step was mixed with 200 g of 10% nitric acid aqueous solution and stirred for 3 hours. Then, the mixture was washed with deionized water and dried to obtain particulate material. (Drying step and amorphization step) The particles obtained in the hydrogen displacement step were calcined at 800°C for 5 hours to dry the contained water and amorphize to obtain particulate material. <Evaluation method> Each physical property was measured by the following method, and the results are shown in Table 1. ・D99 and mode diameter (Dmode) The particle size distribution was measured by the method described in the embodiment, and D99 and mode diameter were calculated. ・Thickness The size of 100 particles randomly selected from a 2000x SEM image was measured. The average value was taken as the thickness. ・Specific surface area The specific surface area was measured by the BET method using nitrogen gas.

[0071] As is clear from Table 1, the particle materials in each example had small D99 / mode diameter values, indicating that aggregation was suppressed, whereas in Comparative Example 1, the D99 / mode diameter was large, indicating that aggregation was progressing. It was found that aggregation between particle materials can be suppressed by replacing water with an organic solvent before the drying process, by adding an organic solvent to create a mixed solvent of water and an organic solvent, or by adding spacer particle material. The sphericity of all added spacer particle materials was 0.8 or higher.

Claims

1. A particle material having a thin plate-like material made of silica, in which the D99 / mode diameter in the particle size distribution measured by the method below is 10 or less, and the (particle diameter of the long side in the spreading direction) / (thickness) is 5 to 50. (Measurement of particle size distribution) The particle size distribution can be measured on a volume basis using a laser diffraction / scattering particle size distribution analyzer. A powdered sample is added to a flow cell through which a dispersion medium is circulated, and the volume-based particle size distribution is measured without performing dispersion treatment by ultrasound or the like. Water is used as the dispersion medium, but methyl ethyl ketone is used if the sample is water-repellent due to surface modification or the like.

2. Mode diameter is 1 μm or more and 20 μm or less, D99 is 50 μm or less, the thickness is 0.1 μm or more and 2 μm or less, and specific surface area is 20 m². ２ The particle material according to claim 1, wherein the particle material is less than or equal to / g.

3. The particle material according to claim 1 or 2, further comprising a second particle material composed of an inorganic material having a volume-average particle size of 0.01 μm or more and 20 μm or less, in an amount of 0.5% by mass or more and 95% by mass or less, based on the total mass.

4. The particle material according to claim 3, wherein the second particle material contains 0.5% or more of a spacer particle material having a sphericity of 0.8 or more, based on the mass of the second particle material.

5. The particulate material according to any one of claims 1 to 4, which is surface-treated with a surface treatment agent.

6. A method for producing a particle material according to any one of claims 1 to 5, wherein the general formula (1): M ２ O・xSiO ２ ・yH ２ A method for producing a particle material, comprising: a layered silicate compound preparation step of preparing a layered silicate compound represented by O (where M is an alkali metal); an acid treatment step of treating the layered silicate compound with an acidic aqueous solution to obtain a composition in which the content of M is reduced; and a drying step of removing the water contained in the composition obtained in the acid treatment step to bring it to a dry state, wherein the drying step is performed while replacing the water contained in the composition with a water-miscible organic solvent, and / or after replacing the water contained in the composition with the organic solvent.

7. A method for producing a particle material as described in claim 4, or claim 5 referencing claim 4, wherein the general formula (1): M ２ O・xSiO ２ ・yH ２ A method for producing a particle material, comprising: a layered silicate compound preparation step of preparing a layered silicate compound represented by O (where M is an alkali metal); an acid treatment step of treating the layered silicate compound with an acidic aqueous solution to obtain a composition in which the content of M is reduced; a drying step of removing the water contained in the composition obtained in the acid treatment step to bring it to a dry state; and a step of adding the second particle material before the drying step is completed.

8. A method for producing a particle material, wherein the drying step is performed while replacing the water contained in the composition with an organic solvent miscible with water, and / or after replacing the water contained in the composition with the organic solvent.

9. A slurry composition comprising a particulate material according to any one of claims 1 to 5 and an organic solvent for dispersing the particulate material.

10. A resin composition comprising a particle material according to any one of claims 1 to 5, and a resin material for dispersing the particle material.

Images