Aluminum nitride microcapsules and their preparation method

Abstract

This application relates to an aluminum nitride microcapsule and its preparation method. The aluminum nitride microcapsule includes a core and a shell. The shell is a spherical, water-resistant polymer material, and the core is a powder encapsulated within the shell. The powder comprises aluminum nitride particles. By encapsulating the spherical aluminum nitride powder with a water-resistant polymer material, the aluminum nitride microcapsule exhibits good hydrolysis resistance and good flowability. When applied to ceramic pressing, this aluminum nitride microcapsule demonstrates good density and superior performance. When added to polymer matrix materials, it offers advantages such as uniform filling, good compatibility, and minimal migration.

Description

Technical Field

[0001] This application relates to the field of aluminum nitride materials technology, and in particular to an aluminum nitride microcapsule and its preparation method. Background Technology

[0002] High-performance aluminum nitride powder typically has a fine particle size, making it prone to agglomeration and poor flowability. During compression molding, it often fails to densely fill the mold, leading to problems such as porosity, voids, delamination, and elastic aftereffects in the molded parts. When used as a plastic filler, it is difficult to disperse uniformly in the matrix material, resulting in significantly reduced thermal conductivity and mechanical properties, thus greatly limiting its practical applications. Furthermore, aluminum nitride is easily oxidized and hydrolyzed in air, causing failure.

[0003] Therefore, it can be seen that the existing aluminum nitride raw material powder has poor hydrolysis resistance and flowability, making it inconvenient for practical applications. Summary of the Invention

[0004] This application provides an aluminum nitride microcapsule and its preparation method to solve the technical problem that the poor hydrolysis resistance and flowability of existing aluminum nitride powder make it inconvenient for practical application.

[0005] In a first aspect, this application provides an aluminum nitride microcapsule, the aluminum nitride microcapsule comprising a core and a shell, the shell being a spherical water-resistant polymer material, the core being a powder encapsulated within the shell, the powder comprising aluminum nitride particles.

[0006] Furthermore, the aluminum nitride microcapsules contain 70%-99% aluminum nitride by mass percentage.

[0007] Furthermore, the aluminum nitride microcapsules have a particle size of 5-100 μm.

[0008] Furthermore, the aluminum nitride microcapsules comprise the following raw materials: aluminum nitride, water-resistant polymer materials, and additives.

[0009] Furthermore, the water-resistant polymer material includes at least one of phenolic resin, epoxy resin, polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyurethane, and ethyl cellulose.

[0010] Furthermore, the additives include dispersants and modifiers; and / or

[0011] The dispersant comprises at least one of hexadecyltrimethylammonium bromide, polyethylene glycol, polypropylene oxide, and sodium dodecyl sulfonate; and / or

[0012] The modifier includes at least one of yttrium oxide, cerium oxide, aluminum oxide, zirconium oxide, molybdenum disulfide, aluminum phosphate, and aluminum dihydrogen phosphate.

[0013] Secondly, this application provides a method for preparing the aluminum nitride microcapsules described in the first aspect, the method comprising:

[0014] Aluminum nitride powder, water-resistant polymer material, additives and organic solvent are mixed and ground, then filtered to obtain a slurry;

[0015] The slurry is atomized into droplets, and the droplets are dried to obtain aluminum nitride microcapsules.

[0016] Furthermore, the preparation method further includes: sieving the aluminum nitride microcapsules using a grading sieve to obtain aluminum nitride microcapsules of different particle sizes.

[0017] Furthermore, the grinding process parameters include: the grinding media being at least one of zirconia grinding balls, alumina grinding balls, and aluminum nitride grinding balls; the ball-to-material mass ratio being (3-30):1; and the grinding slurry having a solid content of 30%-70%.

[0018] Furthermore, the drying process parameters include: inlet temperature of 100-300℃, outlet temperature of 50-150℃, and solvent evaporation rate of 0.5-100kg / h.

[0019] The technical solutions provided in this application have the following advantages compared with the prior art:

[0020] This application provides an aluminum nitride microcapsule, comprising a spherical powder composed of multiple aluminum nitride particles and a water-resistant polymer material coating the surface of the spherical powder. Coating the spherical aluminum nitride powder with the water-resistant polymer material improves the hydrolysis resistance of the aluminum nitride microcapsule and enhances its flowability. When applied to ceramic pressing, this aluminum nitride microcapsule exhibits good density and superior performance. When added to polymer matrix materials, it offers advantages such as uniform filling, good compatibility, and minimal migration. Therefore, this aluminum nitride microcapsule solves the technical problems of poor hydrolysis resistance and flowability of existing aluminum nitride powders, which hinder practical application. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A scanning electron microscope image of an aluminum nitride microcapsule provided in an embodiment of this application;

[0024] Figure 2 An XRD pattern of an aluminum nitride microcapsule provided in an embodiment of this application;

[0025] Figure 3 This is a schematic flowchart illustrating a method for preparing aluminum nitride microcapsules according to an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0028] High-performance aluminum nitride powder typically has a fine particle size, making it prone to agglomeration and poor flowability. During compression molding, it often fails to densely fill the mold, leading to problems such as porosity, voids, delamination, and elastic aftereffects in the molded parts. When used as a plastic filler, it is difficult to disperse uniformly in the matrix material, resulting in significantly reduced thermal conductivity and mechanical properties, thus greatly limiting its practical applications. Furthermore, aluminum nitride is easily oxidized and hydrolyzed in air, causing failure.

[0029] Therefore, it can be seen that the existing aluminum nitride raw material powder has poor hydrolysis resistance and flowability, making it inconvenient for practical applications.

[0030] The technical solution provided by the embodiments of the present invention is to solve the above-mentioned technical problems, and the general idea is as follows:

[0031] like Figure 1 As shown, this application provides an aluminum nitride microcapsule, which includes a core and a shell. The shell is a spherical, water-resistant polymer material, and the core is a powder encapsulated within the shell. The powder comprises aluminum nitride particles.

[0032] This application provides an aluminum nitride microcapsule, comprising a spherical powder composed of multiple aluminum nitride particles and a water-resistant polymer material coating the surface of the spherical powder. Coating the spherical aluminum nitride powder with the water-resistant polymer material improves the hydrolysis resistance of the aluminum nitride microcapsule and enhances its flowability. When applied to ceramic pressing, this aluminum nitride microcapsule exhibits good density and superior performance. When added to polymer matrix materials, it offers advantages such as uniform filling, good compatibility, and minimal migration. Therefore, this aluminum nitride microcapsule solves the technical problems of poor hydrolysis resistance and flowability of existing aluminum nitride powders, which hinder practical application.

[0033] As one embodiment of the present invention, the aluminum nitride microcapsules contain 70%-99% aluminum nitride by mass percentage.

[0034] In this application, the aluminum nitride content in the aluminum nitride microcapsules is maintained at 70%-99%, allowing the microcapsules to retain the properties primarily based on aluminum nitride, while simultaneously improving the hydrolysis resistance and flowability of aluminum nitride. The total content of the remaining components in the aluminum nitride microcapsules is 1%-30%, including water-resistant polymer materials or water-resistant polymer materials and other additives.

[0035] In one embodiment of the present invention, the aluminum nitride microcapsules have a particle size of 5-100 μm.

[0036] In this application, aluminum nitride microcapsules with this particle size are easy to use and can be used as fillers and ceramic powders.

[0037] As one embodiment of the present invention, the aluminum nitride microcapsules include the following raw materials: aluminum nitride, water-resistant polymer materials, and additives.

[0038] In this application, a water-resistant polymer material can be used as a coating for aluminum nitride powder to improve its hydrolysis resistance. Additives can be added as needed to reduce sintering temperature and modify the surface. Aluminum nitride can be directly processed from aluminum nitride powder or other forms of aluminum nitride into powder.

[0039] As one embodiment of the present invention, the water-resistant polymer material includes at least one of phenolic resin, epoxy resin, polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyurethane, and ethyl cellulose.

[0040] In this application, the aforementioned water-resistant polymer material has a certain adhesive effect, dries easily at high temperatures, and is suitable for use as capsule outer skin.

[0041] As one embodiment of the present invention, the additives include dispersants and modifiers; and / or

[0042] The dispersant comprises at least one of hexadecyltrimethylammonium bromide, polyethylene glycol, polypropylene oxide, and sodium dodecyl sulfonate; and / or

[0043] The modifier includes at least one of yttrium oxide, cerium oxide, aluminum oxide, zirconium oxide, molybdenum disulfide, aluminum phosphate, and aluminum dihydrogen phosphate.

[0044] In this application, the dispersant can uniformly disperse aluminum nitride powder, improving ball milling efficiency. The aforementioned dispersant has excellent dispersing effect on ceramic powders, especially in organic solvents. Modifiers can be used to modify the aluminum nitride powder as needed. Yttrium oxide and cerium oxide modifiers can lower the sintering temperature of aluminum nitride ceramics; alumina, zirconium oxide, and molybdenum disulfide modifiers can improve the lubrication properties of the material; aluminum phosphate and aluminum dihydrogen phosphate can enhance the hydrolysis resistance of aluminum nitride.

[0045] Secondly, this application provides a method for preparing the aluminum nitride microcapsules described in the first aspect, such as... Figure 3 As shown, the preparation method includes:

[0046] Aluminum nitride powder, water-resistant polymer material, additives and organic solvent are mixed and ground, then filtered to obtain a slurry;

[0047] The slurry is atomized into droplets, and the droplets are dried to obtain aluminum nitride microcapsules.

[0048] In this application, aluminum nitride powder, after wet milling, breaks up agglomerates, resulting in smaller particle sizes and a narrower particle size distribution. During spray drying, water-resistant polymer materials rapidly dry on the surface of the AlN powder, forming a coating. This coating causes the AlN powder to compactly pack together, forming spherical microcapsule powders. The droplets can be dried using a heated inert gas. Wet ball milling is more efficient, facilitates uniform mixing with polymer materials, and can be combined with spray drying to prepare spherical powders. Organic solvents can dissolve and uniformly disperse the polymer materials.

[0049] The prepared spherical aluminum nitride microcapsule powder has high bulk density and good flowability, facilitating the practical application of aluminum nitride. The microcapsules of this invention are spherical, exhibiting good flowability and low particle size. When applied to ceramic pressing, they provide better density than aluminum nitride powder, require lower sintering temperatures, and result in finer ceramic grains with superior performance. The aluminum nitride microcapsules have good flowability and hydrolysis resistance. When added to polymer matrix materials, they offer advantages such as uniform filling, good compatibility, and low migration, showing promising application prospects in the preparation of polymer composites with high thermal conductivity, heat resistance, enhanced mechanical properties, and friction resistance. This invention employs a spray drying granulation method to prepare spherical aluminum nitride microcapsules. This method is low-cost, suitable for large-scale production, and allows for the preparation of aluminum nitride microcapsules of different sizes, compositions, specifications, and performance differences by adjusting the preparation conditions according to different application fields, thus expanding the refined application directions of aluminum nitride. The product of this invention has good performance, a short production process, recyclable solvents, low production costs, and advantages such as low carbon emissions, environmental friendliness, and high degree of automation, which are in line with the current development trend of energy conservation and environmental protection.

[0050] As one embodiment of the present invention, the preparation method further includes: sieving the aluminum nitride microcapsules with a grading sieve to obtain aluminum nitride microcapsules of different particle sizes.

[0051] As one embodiment of the present invention, the grinding process parameters include: the grinding media being at least one of zirconia grinding balls, alumina grinding balls, and aluminum nitride grinding balls, the ball-to-material mass ratio being (3-30):1, and the grinding slurry having a solid content of 30%-70%.

[0052] In this application, zirconia grinding balls, alumina grinding balls, and aluminum nitride grinding balls are used as grinding media to minimize the introduction of excessive impurities. By adjusting the ball milling conditions, the particle size and specifications of the aluminum nitride microcapsules can be controlled.

[0053] As one embodiment of the present invention, the drying process parameters include: inlet temperature of 100-300℃, outlet temperature of 50-150℃, and solvent evaporation rate of 0.5-100kg / h.

[0054] In this application, by controlling the inlet temperature, outlet temperature, and solvent evaporation rate of spray drying, aluminum nitride microcapsules with different particle sizes, specifications, and certain performance differences can be obtained to meet different needs.

[0055] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0056] Example 1

[0057] A method for preparing aluminum nitride microcapsules and the same, characterized by the following steps:

[0058] (1) Raw material selection: Weigh out 100 parts of aluminum nitride powder, 5 parts of polyvinylpyrrolidone, 2 parts of polyethylene glycol, and 100 parts of anhydrous ethanol by mass.

[0059] (2) Preparation of aluminum nitride:

[0060] Aluminum nitride powder, polyvinylpyrrolidone, polyethylene glycol, and anhydrous ethanol were mixed and then ground using a planetary ball mill and zirconia grinding beads. The ball-to-powder ratio was controlled at 10:1, the ball mill jar filling rate was 70%, and the mixture was ball-milled at 300 r / min for 2 hours. The mixture was then filtered to obtain a slurry.

[0061] The slurry was added to a pressure spray drying tower with nitrogen gas flow as the heat source. The feed rate was 1.5 L / h, the inlet temperature was 160℃, the outlet temperature was 90℃, and the pressure was 0.08 MPa. After drying and shaping, spherical aluminum nitride microcapsules were obtained.

[0062] (3) Performance testing: SEM results of spherical aluminum nitride microcapsules are as follows Figure 1 As shown, the average particle size is 80 μm and the loose packing density is 1.3 g / cm³. 3 The tap density is 1.5 g / cm³. 3 With an angle of repose of 34°, XRD was tested after 10 days in a natural environment, and the results are as follows. Figure 2 As shown, this indicates that it has good resistance to hydrolysis. In comparison, the loose pack density of aluminum nitride powder raw material is 0.35 g / cm³. 3 The tap density is 0.60 g / cm³. 3 The angle of repose is 45°. This indicates that the aluminum nitride microcapsules of the present invention have good resistance to hydrolysis and good flowability.

[0063] Example 2

[0064] A method for preparing aluminum nitride microcapsules and the same, characterized by the following steps:

[0065] (1) Raw material selection: Weigh out 100 parts of aluminum nitride powder, 5 parts of polyacrylic acid, 0.5 parts of hexadecyltrimethylammonium bromide, 100 parts of anhydrous ethanol, 5 parts of yttrium oxide, and 1 part of cerium oxide by weight.

[0066] (2) Preparation of aluminum nitride:

[0067] Aluminum nitride powder, polyacrylic acid, hexadecyltrimethylammonium bromide, anhydrous ethanol, yttrium oxide, and cerium oxide were mixed and then ground using a ball mill and zirconia grinding beads. The ball-to-powder ratio was controlled at 20:1, the ball mill jar filling rate was 60%, and the mixture was ball-milled at 100 r / min for 15 h. The mixture was then filtered to obtain a slurry.

[0068] The slurry was added to a centrifugal spray drying tower with nitrogen gas flow as the heat source. The feed rate was 5.0 L / h, the inlet temperature was 140℃, and the outlet temperature was 80℃. After drying and shaping, spherical aluminum nitride microcapsules were obtained.

[0069] (3) Performance testing: The average particle size of the spherical aluminum nitride microcapsules was 60 μm, and the loose packing density was 1.3 g / cm³. 3 The tap density is 1.4 g / cm³. 3 The angle of repose is 36°.

[0070] Example 3

[0071] A method for preparing aluminum nitride microcapsules and the same, characterized by the following steps:

[0072] (1) Raw material selection: Weigh out 100 parts of aluminum nitride powder, 0.5 parts of aluminum phosphate, 2 parts of aluminum dihydrogen phosphate, 10 parts of polyacrylic acid, 2 parts of polyethylene glycol, and 200 parts of anhydrous ethanol by weight.

[0073] (2) Preparation of aluminum nitride:

[0074] Aluminum nitride powder, aluminum phosphate, aluminum dihydrogen phosphate, polyurethane, polyethylene glycol, and anhydrous ethanol were mixed and then ground using a horizontal sand mill and zirconia grinding beads. The average particle size of the grinding beads was 0.5 mm, the grinding chamber filling rate was 50%, and the mixture was circulated 50 times at a speed of 2700 r / min. The mixture was then discharged, filtered, and a slurry was obtained.

[0075] The slurry was added to a pressure spray drying tower with nitrogen gas flow as the heat source. The feed rate was 0.5 L / h, the inlet temperature was 140℃, the outlet temperature was 70℃, and the pressure was 0.4 MPa. After drying and shaping, spherical aluminum nitride microcapsules were obtained.

[0076] (3) Performance testing: The average particle size of the spherical aluminum nitride microcapsules was 8 μm, and the loose packing density was 0.5 g / cm³. 3 The tap density is 0.7 g / cm³. 3The angle of repose is 42°.

[0077] Example 4

[0078] A method for preparing aluminum nitride microcapsules and the same, characterized by the following steps:

[0079] (1) Raw material selection: Weigh out 100 parts of aluminum nitride powder, 2 parts of aluminum phosphate, 3 parts of aluminum dihydrogen phosphate, 15 parts of polyurethane, 10 parts of polypropylene oxide, 2 parts of aluminum oxide, 3 parts of zirconium oxide, and 200 parts of anhydrous ethanol by weight.

[0080] (2) Preparation of aluminum nitride:

[0081] Aluminum nitride powder, aluminum phosphate, aluminum dihydrogen phosphate, polyurethane, polypropylene oxide, alumina, zirconium oxide, and anhydrous ethanol were mixed and then ground using a horizontal sand mill and zirconium oxide grinding beads. The average particle size of the grinding beads was 0.5 mm, the grinding chamber filling rate was 60%, and the mixture was circulated 60 times at a speed of 2500 r / min. The mixture was then discharged, filtered, and a slurry was obtained.

[0082] The slurry was added to a pressure spray drying tower with nitrogen gas flow as the heat source. The feed rate was 1.5 L / h, the inlet temperature was 180℃, the outlet temperature was 100℃, and the pressure was 0.08 MPa. After drying and shaping, spherical aluminum nitride microcapsules were obtained.

[0083] (3) Performance testing: The average particle size of the spherical aluminum nitride microcapsules was 100 μm, and the loose packing density was 1.5 g / cm³. 3 The tap density is 1.6 g / cm³. 3 The angle of repose is 32°.

[0084] Example 5

[0085] A method for preparing aluminum nitride microcapsules and the same, characterized by the following steps:

[0086] (1) Raw material selection: Weigh out 100 parts of aluminum nitride powder, 2 parts of polyvinyl butyral, 0.5 parts of hexadecyltrimethylammonium bromide, 200 parts of anhydrous ethanol, 5 parts of yttrium oxide, and 1 part of cerium oxide by mass.

[0087] (2) Preparation of aluminum nitride:

[0088] Aluminum nitride powder, polyvinyl butyral, hexadecyltrimethylammonium bromide, anhydrous ethanol, yttrium oxide, and cerium oxide were mixed and then ground using a ball mill and zirconia grinding beads. The ball-to-powder ratio was controlled at 3:1, the ball mill jar filling rate was 30%, and the mixture was ball-milled at 100 r / min for 15 h. The mixture was then filtered to obtain a slurry.

[0089] The slurry was added to a centrifugal spray drying tower with nitrogen gas flow as the heat source. The feed rate was 10L / h, the inlet temperature was 300℃, and the outlet temperature was 150℃. After drying and shaping, spherical aluminum nitride microcapsules were obtained.

[0090] (3) Performance testing: The average particle size of the spherical aluminum nitride microcapsules was 30 μm, and the loose packing density was 0.8 g / cm³. 3 The tap density is 1.0 g / cm³. 3 The angle of repose is 40°.

[0091] Comparative Example 1

[0092] The polyvinylpyrrolidone and polyethylene glycol in Example 1 were removed, and the rest were the same as in Example 1;

[0093] The obtained spherical aluminum nitride microcapsules had an average particle size of 1.5 μm and a loose packing density of 0.38 g / cm³. 3 The tap density is 0.60 g / cm³. 3 The angle of repose is 45°.

[0094] Comparative Example 2

[0095] The process of atomizing the slurry into droplets in Example 1 is modified as follows: the slurry is placed in a tray and dried under vacuum at 80°C for 24 hours. After cooling, the material is taken out. The material contains lumps. It is then dry-milled in a ball mill for 0.5 hours to break up the material and then sieved to obtain aluminum nitride microcapsules. The rest is the same as in Example 1.

[0096] The obtained aluminum nitride microcapsules are mostly irregular elliptical in shape, with varying edge morphology.

[0097] In summary, the spherical aluminum nitride microcapsule powder prepared by this invention has high bulk density and good flowability, facilitating the practical application of aluminum nitride. The spherical microcapsules of this invention exhibit good flowability and low particle size, resulting in better compactness than aluminum nitride powder when applied to ceramic pressing, requiring lower sintering temperatures, producing finer ceramic grains with superior performance. The aluminum nitride microcapsules have good flowability and hydrolysis resistance. When added to polymer matrix materials, they offer advantages such as uniform filling, good compatibility, and low migration, showing promising application prospects in the preparation of polymer composites with high thermal conductivity, heat resistance, enhanced mechanical properties, and friction resistance. This invention employs a spray drying granulation method, which is low-cost and suitable for large-scale production. Furthermore, by controlling the preparation conditions according to different application fields, aluminum nitride microcapsules of different sizes, compositions, specifications, and performance differences can be prepared, expanding the refined application directions of aluminum nitride. The products of this invention have good performance, a short production process, recyclable solvents, low production costs, and advantages such as low carbon footprint, environmental friendliness, and high automation, aligning with current energy-saving and environmental protection trends.

[0098] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0099] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0100] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An aluminum nitride microcapsule, characterized in that, The aluminum nitride microcapsules comprise a core and a shell. The shell is a spherical, water-resistant polymer material, and the core is a powder encapsulated within the shell. The powder comprises aluminum nitride particles. The aluminum nitride content in the microcapsules is 70%-99% by mass. The microcapsules are spherical with a particle size of 5-100 μm. The aluminum nitride microcapsules comprise the following raw materials: The invention comprises aluminum nitride, a water-resistant polymer material, and additives; the water-resistant polymer material includes at least one of phenolic resin, epoxy resin, polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyurethane, and ethyl cellulose; the additives include dispersants and modifiers; the dispersant includes at least one of hexadecyltrimethylammonium bromide, polyethylene glycol, polypropylene oxide, and sodium dodecyl sulfonate; the modifier includes at least one of yttrium oxide, cerium oxide, aluminum oxide, zirconium oxide, molybdenum disulfide, aluminum phosphate, and aluminum dihydrogen phosphate. The aluminum nitride microcapsules were prepared using a spray drying process.

2. A method for preparing aluminum nitride microcapsules according to claim 1, characterized in that, The preparation method includes: Aluminum nitride powder, water-resistant polymer material, additives and organic solvent are mixed and ground, then filtered to obtain a slurry; The slurry is atomized into droplets, and the droplets are dried to obtain aluminum nitride microcapsules.

3. The preparation method according to claim 2, characterized in that, The preparation method further includes: sieving the aluminum nitride microcapsules using a grading sieve to obtain aluminum nitride microcapsules of different particle sizes.

4. The preparation method according to claim 2, characterized in that, The grinding process parameters include: the grinding media is at least one of zirconia grinding balls, alumina grinding balls and aluminum nitride grinding balls, the ball-to-material mass ratio is (3-30):1, and the solid content of the grinding slurry is 30%-70%.

5. The preparation method according to claim 2, characterized in that, The drying process parameters include: inlet temperature of 100-300℃, outlet temperature of 50-150℃, and solvent evaporation rate of 0.5-100 kg / h.

Images