Hollow silicon dioxide particles as well as preparation method and application thereof

Abstract

The invention discloses a hollow silicon dioxide particle. The ratio of the hollow area of the hollow silicon dioxide particle to the total area of the particle in a transmission electron microscope photo is 10-96%; the average maximum diameter of the hollow silica particles is 100 nm to 10 [mu] m; a shell layer of the hollow silicon dioxide particle is formed by stacking nano particles, the average diameter of nano convex particles in the shell layer is 4-100 nm, and the ratio of the average diameter of the nano convex particles to the average maximum diameter of the hollow silicon dioxide particle is 1 / 2500-1 / 5. The ratio of the average diameter of the nanometer protruding particles on the surfaces of the hollow silicon dioxide particles to the average maximum diameter of the hollow silicon dioxide particles ranges from 1 / 2500 to 1 / 5, so that the bonding force between the hollow silicon dioxide particles serving as filler and resin is high, the fluidity is good when the hollow silicon dioxide particles are added into the resin, and the hollow silicon dioxide particles are suitable for serving as packaging filler of semiconductor devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of fillers, and particularly relates to a hollow silica particle, a preparation method thereof and an application thereof. Background Art

[0002] Due to their low expansion coefficient and dielectric constant, hollow silica particles are widely used in the field of semiconductor device packaging. In the prior art, hydrolyzable organosiloxanes are usually used to form a polysiloxide coating layer on the surface of the core microspheres through hydrolysis and condensation, and then the core microspheres are removed by heat treatment to form hollow silica particles. However, the particles are prone to adhesion before heat treatment, which easily leads to broken spheres during the subsequent heat treatment process. During the heat treatment process, when the core decomposes into gas and is discharged, it is also easy to cause broken spheres or cracks in the shell layer of the formed hollow silica particles. When the hollow silica particles have cracks, their water absorption capacity will increase. When these particles are used as packaging materials for semiconductor devices, due to the large water content, the dielectric loss of the devices increases.

[0003] In addition, as a packaging material, the greater the surface roughness of the particles, the more obvious the "biting" with the resin, that is, the greater the binding force with the resin. However, if the roughness is too large, its fluidity becomes poor when added to the resin, thus affecting the packaging effect.

[0004] Therefore, there is an urgent need to provide a hollow silica particle with a dense shell layer, which can be tightly combined with the resin and has good fluidity when added to the resin. Summary of the Invention

[0005] In order to solve at least one of the above problems, the present invention provides a hollow silica particle, a preparation method thereof and an application thereof.

[0006] The present invention provides a hollow silica particle. The ratio of the hollow area to the total area of the particle in the transmission electron microscope photograph of the hollow silica particle is 10% - 90%; the average maximum diameter of the hollow silica particle is 100 nm - 10 μm; the shell layer of the hollow silica particle is a stack of nanoparticles, the average diameter of the nano-protruding particles in the shell layer is 4 - 100 nm, and the ratio of the average diameter of the nano-protruding particles to the average maximum diameter of the hollow silica particle is between 1 / 2500 and 1 / 5.

[0007] According to an embodiment of the present invention, the ratio of the hollow area to the total area of the hollow silica particles in a transmission electron microscope photograph is 20% to 80%; preferably 30% to 70%; the average maximum diameter of the hollow silica particles is 200 nm to 9 μm; preferably 300 nm to 8 μm; the shell layer of the hollow silica particles is a packing of nanoparticles, the average diameter of the nano-protruding particles in the shell layer is 5 to 80 nm, and the ratio of the average diameter of the nano-protruding particles to the average maximum diameter of the hollow silica particles is between 1 / 1800 and 1 / 5; preferably, the average diameter of the nano-protruding particles is 5 to 60 nm, and the ratio of the average diameter of the nano-protruding particles to the average maximum diameter of the hollow silica particles is between 1 / 1600 and 1 / 5.

[0008] According to another embodiment of the present invention, the BET specific surface area of the hollow silica particles is 50 m 2 / g or less; preferably 20 m 2 / g or less.

[0009] According to another embodiment of the present invention, under the environmental conditions of 25°C and 50% RH, the water content of the hollow silica particles after being placed for 48 hours is not higher than 2800 ppm; preferably, not higher than 1500 ppm.

[0010] The present invention provides a method for preparing the above-mentioned hollow silica particles, including: S1, coating a first polysiloxane on the surface of polymer particles to form first particles, wherein the molar content of the polysiloxane with a T unit in the main chain in the first polysiloxane is at least 70% or more, and the T unit is R1SiO 3 / 2 , R1 is a hydrocarbon group with 1 to 16 carbon atoms; S2, mixing carbonaceous materials with the first particles, and performing heat treatment in an inert gas atmosphere at 250 to 650°C to thermally decompose the polymer particles into carbon to form second particles; S3, calcining the second particles in an oxygen-containing gas atmosphere at 800 to 1200°C.

[0011] According to an embodiment of the present invention, the material of the polymer particles is one or more of polystyrene, polymethyl methacrylate, polyacrylate methyl ester, phenol resin, melamine resin, polyurethane, and epoxy resin; and / or the particle size of the polymer particles is 80 nm to 9 μm.

[0012] According to another embodiment of the present invention, forming the first particles in the step S1 includes: S11, first configuring an oxygen-containing non-ionic surfactant, water, and the polymer particles into a dispersion; S12, mixing water and a first silicon source precursor to form a hydrolysis product solution; S13, after mixing the dispersion and the hydrolysis product solution, adding an alkali solution to make the pH of the final reaction system 8-11, and reacting for 1-10 h; wherein, the mass ratio of the polymer particles, the oxygen-containing non-ionic surfactant, and water is 1:0.1-0.01:50-200; the mass ratio of the polymer particles, the first silicon source precursor, and water is 1:1-8:50-200.

[0013] According to another embodiment of the present invention, a second silicon source precursor is added after the step S13; wherein, the mass ratio of the polymer particles and the second silicon source precursor is 1:1-8, and the second silicon source precursor hydrolyzes to form a second polysiloxane coated on the outer surface of the first polysiloxane, and the molar content of the polysiloxane with a T unit in the main chain in the second polysiloxane is more than 70%.

[0014] According to another embodiment of the present invention, the oxygen-containing non-ionic surfactant is polyvinylpyrrolidone, polyether P123, polyether F127; and / or the alkali solution is an aqueous ammonia solution with a mass concentration of 25%-28%, a tetramethylammonium hydroxide solution with a mass concentration of 25%-28%, a sodium hydroxide solution with a mass concentration of 1%-10%, or a potassium hydroxide solution with a mass concentration of 1%-10%; and / or in the step S13, the alkali solution is added to the reaction system at a constant speed within 0.5 min - 1 h.

[0015] According to another embodiment of the present invention, the carbon material is one or more of graphite, acetylene black, diamond, fullerene, and carbene; and / or the mass ratio of the first particles to the carbon material is 1:0.05-5.

[0016] According to another embodiment of the present invention, in the step S2, the heat treatment is to heat up to 250-650°C at a heating rate of 0.5-10°C / min and keep warm for 3-20 h; the oxygen mass content in the inert gas atmosphere is less than 10%, and the flow rate of the inert gas is 30-1000 mL / min.

[0017] According to another embodiment of the present invention, in the step S3, the heat treatment is to heat up to 800-1200°C at a heating rate of 0.5-10°C / min and keep warm for 1-20 h; the oxygen content in the oxygen-containing gas atmosphere is 10%-100%, and the flow rate of the oxygen-containing gas is 30-1000 mL / min.

[0018] According to another embodiment of the present invention, the first silicon source precursor and the second silicon source precursor are each independently an alkyltrialkoxysilane or an alkyltrichlorosilane; preferably, one or both of methyltrimethoxysilane and methyltrichlorosilane.

[0019] The present invention also provides an application of the above hollow silica particles, or the hollow silica particles prepared by the above preparation method, as a semiconductor encapsulation material, a substrate material, a supported catalyst, a drug carrier or a cosmetic.

[0020] The surface of the hollow silica particles of the present invention has a ratio of the average diameter of the nano-protruding particles to the average maximum diameter of the hollow silica particles in the range of 1 / 2500 to 1 / 5. Therefore, the hollow silica particles of the present invention have a high binding force with the resin as a filler and good fluidity when added to the resin, and are suitable as an encapsulation filler for semiconductor devices. Moreover, the shell layer of the hollow silica particles prepared by the preparation method of the present invention is dense and has almost no cracks. Therefore, the water absorption capacity of the particles is low, and the dielectric loss can be reduced when used as an encapsulation filler for semiconductor devices. In the preparation method of the present invention, in the stage of forming the polysiloxane hollow particles, by selecting specific types and amounts of additives and coordinating with the addition amount, addition speed and addition order of the alkali solution to control the formation speed of the polysiloxane, self-polymerization of the polysiloxane can be avoided, and it can be coated on the surface of the inner core to avoid the formation of solid spheres. During the heat treatment process, carbon materials are added as isolation materials to avoid particle adhesion during the heat treatment process, thereby avoiding the breakage of the particles caused by the separation of the adhered particles during the post-treatment process. And the breakage of the particles can be controlled by controlling the heat treatment temperature during the heat treatment process. Thus, the yield of the hollow silica particles is increased and the production cost of the hollow silica particles is reduced. Description of the Drawings

[0021] Figure 1 It is an enlarged schematic diagram for explaining the "hollow ratio" in this patent.

[0022] Figure 2 It is an enlarged schematic diagram for explaining the "maximum diameter" of the hollow silica particles and the "diameter" of the nano-protruding particles in the shell layer.

[0023] Figure 3 It is a partial enlarged schematic diagram for explaining the "diameter" of the nano-protruding particles in the shell layer of the hollow silica particles.

[0024] Figure 4 It is an enlarged schematic diagram for explaining the yield of the hollow spheres.

[0025] Figure 5 It is an SEM photograph of the hollow silica particles prepared in Example 1.

[0026] Figure 6It is the TEM photograph of the hollow silica particles prepared in Example 1.

[0027] Figure 7 It is the SEM photograph of the silica particles prepared in Comparative Example 1. Detailed implementation manners

[0028] The present invention will be further described below in conjunction with embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are usually only a part of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] For the hollow silica particles of the present invention, the ratio of the hollow area to the total area of the particles in the transmission electron microscope photograph is 10% - 96%; the average maximum diameter of the hollow silica particles is 100 nm - 10 μm; the shell layer of the hollow silica particles is a stack of nanoparticles, and the average diameter of the nano-protruding particles in the shell layer is 4 - 100 nm, and the ratio of the average diameter of the nano-protruding particles to the average maximum diameter of the hollow silica particles is between 1 / 2500 and 1 / 5. The surface of the hollow silica particles of the present invention has a ratio of the average diameter of the nano-protruding particles to the average maximum diameter of the hollow silica filler particles between 1 / 2500 and 1 / 5. Therefore, the hollow silica particles of the present invention have a high bonding force with the resin as a filler and good fluidity when added to the resin, and are suitable as a packaging filler for semiconductor devices.

[0030] In this patent, the term "the ratio of the hollow area to the total area of the particles in the transmission electron microscope photograph" is also called "hollow ratio". Refer to Figure 1 , in this patent, the "hollow ratio" refers to the ratio of the area of the blue region representing the hollow part to the total area of the green region representing the shell and the blue region representing the hollow part in the transmission electron microscope photograph, that is, the hollow ratio = area of the blue region / (area of the blue region + area of the green region).

[0031] As Figure 2 shown, in this patent, the term "the maximum diameter of the hollow silica particles" refers to the major axis of the hollow silica particles. The maximum average diameter of the hollow silica particles in this patent is characterized by an Apreo2 CHiVac scanning electron microscope (SEM). Randomly select 100 hollow silica particles in the obtained SEM photograph, measure the maximum diameter of each particle through NanoMeasurer software, and then calculate the average maximum diameter.

[0032] Figure 2 and Figure 3The diameter of the nano-protruding particles in the shell layer is shown. In this patent, the average diameter of the nano-protruding particles is obtained by randomly selecting 10 hollow silica particles from the SEM photos obtained by an Apreo2 CHiVac scanning electron microscope (SEM). For each hollow silica particle, 50 protruding nano-particles are randomly selected on the surface, and the average diameter of the nano-protruding particles in the shell layer is calculated by ImageJ software.

[0033] In an alternative embodiment, the hollow ratio of the hollow silica particles is 20% to 80%, preferably 30% to 70%. In practical applications, the hollow ratio of the hollow silica particles can be specifically selected according to actual needs, such as but not limited to 40%, 50%, 60%, etc. The average maximum diameter of the hollow silica particles is 200 nm to 9 μm; preferably 300 nm to 8 μm. The appropriate average maximum diameter can be selected according to needs in practical applications, such as but not limited to 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, etc. The average diameter of the nano-protruding particles in the shell layer of the hollow silica particles is 5 to 80 nm, and the ratio of the average diameter of the nano-protruding particles to the average maximum diameter of the hollow silica particles is between 1 / 1800 and 1 / 5; preferably, the average diameter of the nano-protruding particles is 5 to 60 nm, and the ratio of the average diameter of the nano-protruding particles to the average maximum diameter of the hollow silica particles is between 1 / 1600 and 1 / 5.

[0034] In an alternative embodiment, the BET specific surface area of the hollow silica particles is 50 m 2 / g or less; preferably 10 to 20 m 2 / g or less.

[0035] In an alternative embodiment, under the environmental conditions of 25°C and 50% RH, the water content of the hollow silica particles after being placed for 48 hours is not higher than 2800 ppm; preferably, not higher than 1500 ppm. Since the hollow silica particles of the present invention have a small water absorption amount, the dielectric loss can be reduced when used as a packaging filler for semiconductor devices.

[0036] The hollow silica particles of the present invention can be prepared by the following preparation method. The preparation method includes: S1, coating a first polysiloxane on the surface of polymer particles to form first particles, wherein the molar content of the polysiloxane with a T unit in the main chain in the first polysiloxane is at least 70%, and the T unit is R1SiO 3 / 2, R1 is a hydrocarbon group having 1 to 16 carbon atoms; S2, after mixing the carbon material with the first particles, heat-treating in an inert gas atmosphere at 250 to 650 °C to thermally decompose the polymer particles into carbon to form the second particles; S3, calcining the second particles in an oxygen-containing gas atmosphere at 800 to 1200 °C. The hollow silica particles prepared by the preparation method of the present invention have a dense shell layer and almost no cracks, so the water absorption capacity of the particles is low, and the dielectric loss can be reduced when used as a packaging filler for semiconductor devices. In the preparation method of the present invention, in the stage of forming the polysiloxane hollow particles, by selecting a specific type and amount of additives and coordinating with the addition amount, addition rate and addition order of the alkali solution to control the formation rate of the polysiloxane, self-polymerization of the polysiloxane can be avoided, and it can be coated on the surface of the inner core to avoid the formation of solid spheres. Adding a carbon material as an isolation material during the heat treatment process can avoid the adhesion of particles during the heat treatment process, thereby avoiding the breakage of the particles caused by the separation of the adhered particles during the post-treatment process. And the breakage of the particles can be controlled by controlling the heat treatment temperature during the heat treatment process. Thus, the yield of the hollow silica particles is increased, and the production cost of the hollow silica particles is reduced.

[0037] In step S1, the material of the polymer particles can be any suitable material that has no influence on the performance of the finally prepared hollow silica particles during the preparation process and can be removed by heat. For example, the material of the polymer particles can be one or more of polystyrene, polymethyl methacrylate, polyacrylate methyl ester, phenol resin, melamine resin, polyurethane, epoxy resin. The particle size of the polymer particles is 80 nm to 9 μm. The particle size of the polymer particles can be determined according to factors such as the hollow ratio and the average maximum diameter of the pre-prepared hollow silica particles. For example, but not limited to, the average maximum diameter of the particles can be 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, etc. The polymer particles can be in any suitable shape, such as but not limited to spherical, cubic, polyhedral, ellipsoidal, etc.

[0038] The specific steps of forming the first particles in step S1 may include: S11, first preparing a dispersion liquid by mixing an oxygen-containing nonionic surfactant, water and polymer particles; S12, mixing water and a first silicon source precursor to form a hydrolysis product solution; S13, after mixing the dispersion liquid and the hydrolysis product solution, adding an alkali solution to make the pH of the final reaction system 8 to 11, and reacting for 1 to 10 h.

[0039] Specifically, in step S11, an oxygen-containing nonionic surfactant, polymer particles and water are first formed into a dispersion. Since the oxygen-containing nonionic surfactant contains oxygen (such as a carbonyl group, etc.), it is easy to bond with the silicon source precursor, so that the polysiloxane formed by the hydrolysis of the silicon source precursor can more easily coat the surface of the polymer particles. The oxygen-containing nonionic surfactant can be one or more of polyvinylpyrrolidone, polyether P123, and polyether F127.

[0040] In step S12, the first silicon source precursor is hydrolyzed. This process can be carried out by stirring at room temperature. The stirring time can be between 20 and 60 minutes.

[0041] Finally, in step S13, after mixing the dispersion with the hydrolysis product solution, an alkali solution is added to the solution to cause the hydrolysis product to condense to form a polysiloxane coating on the surface of the polymer particles. The addition rate of the alkali solution affects the average diameter of the nano-protrusion particles in the finally formed hollow silica particle shell layer and the self-aggregated particles in the system. Within a certain range, when the addition rate of the alkali solution is greater, the average diameter of the nano-protrusion particles is greater, and the more self-aggregated particles and the larger their diameters are. In order to obtain the average diameter range of the nano-protrusion particles in the shell layer defined by the present invention, the alkali solution is added to the reaction system at a constant speed within 0.5 minutes to 1 hour. When the addition rate of the alkali solution is too high (i.e., the time for adding the alkali solution is less than 0.5 minutes), the polysiloxane is likely to self-aggregate into small non-hollow structures. If the addition rate of the alkali solution is too low (i.e., the time for adding the alkali solution is greater than 1 hour), an uneven coating phenomenon will occur, that is, a "snowman-like" structure, and finally a "bowl-like" structure will be formed after heat treatment, and a closed hollow structure cannot be formed.

[0042] In step S13, the alkali solution can be an aqueous ammonia solution with a mass concentration of 25% - 28%, a tetramethylammonium hydroxide solution with a mass concentration of 25% - 28%, a sodium hydroxide solution with a mass concentration of 1% - 10%, or a potassium hydroxide solution with a mass concentration of 1% - 10%.

[0043] In step S13, adding the alkali solution makes the final reaction system pH 8 - 11. The pH value of the final reaction system reflects the amount of alkali added. The greater the final pH, the greater the amount of alkali added. The greater the amount of alkali added to the system, the greater the average diameter of the nano-protrusion particles in the shell layer. When the amount of alkali added is too large (i.e., the final reaction system pH is greater than 11), the polysiloxane is easily self-aggregated into small non-hollow structures. When the amount of alkali added is too small (i.e., the final reaction system pH is less than 8), the precursor hydrolysis is insufficient to form a gel state, showing a "jelly-like" state and forming a block structure instead of a hollow structure.

[0044] In an alternative embodiment, the mass ratio of the polymer particles, the oxygen-containing nonionic surfactant, and water in step S1 is 1:0.1 to 0.01:50 to 200. The mass of water in this step refers to the sum of the amounts of water in steps S11 and S12. The amounts of water used in steps S11 and S12 are such that the silicon source precursor can be fully hydrolyzed in step S12. In this step, when the content of the oxygen-containing nonionic surfactant is too low (i.e., the mass ratio of the polymer particles to the oxygen-containing nonionic surfactant is greater than 1:0.01, and the mass ratio of the oxygen-containing nonionic surfactant to water is less than 0.01:200), the content of the surfactant in water is too small, and it is not easy for the polycondensate of the hydrolysis product of the silicon source precursor to coat the surface of the polymer particles in step S13, so a hollow structure cannot be formed; when the content of the oxygen-containing nonionic surfactant is too high (i.e., the mass ratio of the polymer particles to the oxygen-containing nonionic surfactant is less than 1:0.1, and the mass ratio of the oxygen-containing nonionic surfactant to water is greater than 0.1:50), the content of the surfactant in water is too large, and the viscosity of the aqueous solution is too high. In step S13, the polycondensate of the hydrolysis product of the silicon source precursor is likely to agglomerate and cannot completely coat the surface of the polymer particles, so a hollow structure cannot be formed.

[0045] In an alternative embodiment, the mass ratio of the polymer particles, the first silicon source precursor, and water is 1:1 to 8:50 to 200. The mass of water in this ratio range refers to the sum of the amounts of water in steps S11 and S12. When the amount of the first silicon source precursor used is too small (i.e., the mass ratio of the polymer particles to the first silicon source precursor is greater than 1:1, and the mass ratio of the first silicon source precursor to water is less than 1:200), the polycondensate of the hydrolysis product of the silicon source precursor is not sufficient to coat the polymer particles, so a hollow structure cannot be formed; when the amount of the first silicon source precursor used is too large (i.e., the mass ratio of the polymer particles to the first silicon source precursor is less than 1:8, and the mass ratio of the first silicon source precursor to water is greater than 1:50), the polycondensate of the hydrolysis product of the first silicon source precursor is too much, and self-aggregated polysiloxane spheres are likely to form in the system.

[0046] The molar content of the polysiloxane with a T unit in the main chain in the first polysiloxane coating the surface of the polymer particles is at least 70% or more. When the molar content of the polysiloxane with a T unit in the main chain in the first polysiloxane is less than 70%, the density of the shell of the obtained hollow silica particles is insufficient, which will cause the specific surface area of the hollow silica particles to be too large, so the water absorption will increase, resulting in a large dielectric loss when used as a packaging filler for semiconductor devices. Preferably, the first polysiloxane is 100% a polysiloxane with a T unit in the main chain. When the polysiloxane with a T unit in the main chain in the first polysiloxane is less than 100%, the other polysiloxane can be a polysiloxane with a Q unit in the main chain (SiO 4 / 2) and / or D unit (SiO 2 / 2 ) polysiloxane. According to the application scenario of the hollow silica particles, the molar content of the polysiloxane with a T unit as the main chain in the first polysiloxane can be selected as an appropriate value, such as but not limited to 70%, 75%, 85%, 85%, 90%, 95%, 100%, etc.

[0047] In an alternative embodiment, a second silicon source precursor can be added after step S13. The second silicon source precursor hydrolyzes to form a second polysiloxane coating on the outer surface of the first polysiloxane. The molar content of the polysiloxane with a T unit as the main chain in the second polysiloxane is above 70%. Similarly, according to the application scenario of the hollow silica particles, the molar content of the polysiloxane with a T unit as the main chain in the second polysiloxane can be selected as an appropriate value, such as but not limited to 70%, 75%, 85%, 85%, 90%, 95%, 100%, etc. In an alternative embodiment, the mass ratio of the polymer particles to the second silicon source precursor is 1:1 to 8.

[0048] In an alternative embodiment, the first silicon source precursor and the second silicon source precursor are independently a hydrocarbyl trialkoxysilane or a hydrocarbyl trichlorosilane. Preferably, it is one or two of methyltrimethoxysilane and methyltrichlorosilane.

[0049] After forming the first particles, step S2 is carried out. In step S2, using carbonaceous material as the isolation powder and mixing it with the first particles can avoid the adhesion between the first particles, thereby avoiding the ball breakage caused during the dispersion. The carbonaceous material can be one or more of graphite, acetylene black, diamond, fullerene, and carbene. The mass ratio of the first particles to the carbonaceous material is 1:0.05 to 5. The appropriate mass ratio of the first particles to the carbonaceous material can be selected according to the actual situation, such as factors such as the average particle size of the first particles, such as but not limited to 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.8, 1:0.9, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, etc.

[0050] After mixing the first particles with the carbonaceous material, heat treatment is carried out in an inert gas atmosphere to carbonize the polymer particles. The inert gas atmosphere refers to an inert gas with an oxygen mass content lower than 10%, such as but not limited to nitrogen, air with an oxygen mass content less than 10%, etc. In order to avoid the ball breakage phenomenon in this step, the temperature of the heat treatment is controlled at 250 - 650 °C and held for more than 3 hours, such as 3 - 20 h. Preferably, the heating rate of this step is 0.5 - 10 °C / min, and the flow rate of the inert gas is 30 - 1000 mL / min.

[0051] Subsequently, step S3 is carried out, in which the second particles are calcined in an oxygen-containing gas atmosphere to vaporize the carbon inside the particles (obtained after carbonization of the polymer particles in step S2) (generating gases such as CO2 and CO) and remove them. In this step, the oxygen-containing gas atmosphere means that the oxygen content is 10% - 100%. Appropriate oxygen content can be selected according to needs, such as 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or pure oxygen, etc. The flow rate of the oxygen-containing gas is 30 - 1000 mL / min. In order to avoid breakage of the balls in this step and the size of the nano-protruding particles being out of the expected range due to too high temperature, the calcination temperature in this step is 800 - 1200 °C, and the heat preservation time is 1 - 20 h. Preferably, the heating rate in this step is 0.5 - 10 °C / min.

[0052] The hollow silica particles of the present invention can be used in semiconductor packaging materials, substrate materials, supported catalysis, drug loading or cosmetics.

[0053] The present invention is further described below through specific examples. However, these examples are merely exemplary and do not constitute any limitation to the protection scope of the present invention. In the following examples and comparative examples, the reagents, materials and instruments used, if not otherwise specified, can be obtained commercially.

[0054] The characterization and testing methods involved in the following examples and comparative examples are as follows:

[0055] In the structural characterization, the hollow silica particles are characterized by a FEI Talos F200S transmission electron microscope (TEM). In the obtained TEM photos, 20 hollow silica particles are randomly selected, and the total area of the hollow part and the total area of the powder are calculated through ImageJ software. The hollowness rate is equal to the ratio of the area of the hollow part to the total area of the particles.

[0056] In the structural characterization, the hollow silica particles are characterized by an Apreo2 CHiVac scanning electron microscope (SEM). In the obtained SEM photos, 10 hollow silica particles are randomly selected, and 50 protruding nano-particles are randomly selected on the surface of each hollow silica particle. The average diameter of the shell nano-protruding particles is calculated through ImageJ software.

[0057] In the structural characterization, the hollow silica particles are characterized by an Apreo2 CHiVac scanning electron microscope (SEM). In the obtained SEM photos, 100 hollow silica particles are randomly selected, and the maximum diameter of each particle is measured through NanoMeasurer software, and then the average maximum diameter is calculated.

[0058] In structural characterization, the yield of hollow silica was characterized by using a FEI Talos F200S transmission electron microscope (TEM). In the obtained TEM images, 50 particles were randomly selected. The yield of hollow spheres was calculated by dividing the number of hollow particles by the total number of particles. That is, as Figure 4 shown, the yield = number of hollow particles / total number of particles, and the total number of particles was 50.

[0059] The specific surface area was measured by a SHIMADZU FlowSorb III 2305.

[0060] In performance testing, the binding performance between hollow silica particles and resin was characterized by the "number of peeled particles bound to resin". The test method for the "number of peeled particles bound to resin" was as follows: The hollow silica particles were dispersed into an epoxy resin and heated for curing. Then, ion beam slicing and polishing were carried out. Subsequently, the interface between the hollow silica particles and the resin was observed by an electron microscope. Random areas were selected, and the number of particles with peeled interfaces among 1000 particles was counted. The obtained number of particles with peeled interfaces was the number of peeled particles bound to resin.

[0061] In performance testing, the fluidity of the mixture of hollow silica particles and resin was tested by a DHR rheometer. The test method was as follows: The hollow silica particles and epoxy resin were uniformly mixed at a mass ratio of 7:3. The mixture was dropped into a fixture with a gap of 350 μm, and the rotational speed was 1 S at 25 °C -1 to obtain the viscosity value through testing.

[0062] In the water content test, the water content of the particles was the water content at 200 °C, which was tested by a Karl Fischer moisture meter. The instrument was a Mitsubishi Chemical CA-310, and the determination method was the Coulometric method.

[0063] Example 1

[0064] Step S1: 5000 g of water, 1 g of polyvinylpyrrolidone, and 100 g of polystyrene microspheres with a particle size of 600 nm were added to a reactor to prepare a homogeneous emulsion (Step S11); 5000 g of water and 400 g of methyltrimethoxysilane were added to another reactor and stirred at 25 °C for 2 h for hydrolysis (Step S12); then the polymer emulsion and the hydrolysis product solution were mixed. Next, a 25% tetramethylammonium hydroxide solution was added thereto at a constant rate. The addition time was 50 min, and the final pH of the reaction system was 9. The reaction was carried out at 25 °C for 10 h. After washing and drying, polystyrene microsphere@polysiloxane core-shell composites were obtained (Step S13);

[0065] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composite with 5 g of acetylene black evenly and put them into a tube furnace. Set the nitrogen flow rate to 300 mL / min. Under the nitrogen atmosphere, heat it to 550 °C at a rate of 1 °C / min and keep it for 8 h;

[0066] Step S3: Switch the gas in the tube furnace to air. Set the air flow rate to 300 mL / min. Under the air atmosphere, heat it to 1000 °C at a rate of 0.5 °C / min and keep the particles at 1000 °C for 1 h to remove the carbon on the particle surface and densify the particle surface, obtaining a kind of hollow silica particles with a rough surface.

[0067] Figure 5 and Figure 6 Show the SEM and TEM photos of the particles prepared in this example. It can be seen from these two photos that the particles prepared in this example are of a hollow structure.

[0068] Example 2

[0069] Step S1: Add 5000 g of water, 1 g of polyether F127 and 100 g of polystyrene microspheres with a particle size of 600 nm into a reactor to prepare a homogeneous emulsion (Step S11); add 5000 g of water and 400 g of methyltrimethoxysilane into another reactor and stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add 25% tetramethylammonium hydroxide solution into it at a uniform speed. The addition time is 50 min, and the final pH of the reaction system is 11. React at 25 °C for 10 h, and obtain polystyrene microsphere@polysiloxane core-shell composite after washing and drying (Step S13);

[0070] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composite with 5 g of graphite evenly and put them into a tube furnace. Set the nitrogen flow rate to 300 mL / min. Under the nitrogen atmosphere, heat it to 450 °C at a rate of 1 °C / min and keep it for 20 h;

[0071] Step S3: Switch the gas in the tube furnace to air. Set the air flow rate to 300 mL / min. Under the air atmosphere, heat it to 950 °C at a rate of 5 °C / min and keep the particles at 950 °C for 2 h to remove the carbon on the particle surface and densify the particle surface, obtaining a kind of hollow silica particles with a rough surface.

[0072] Example 3

[0073] Step S1: Add 5000 g of water, 1 g of polyether P123, and 100 g of polystyrene microspheres with a particle size of 80 nm into a reactor to prepare a uniform emulsion (Step S11); add 5000 g of water and 400 g of methyltrimethoxysilane into another reactor, stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add a 25% tetramethylammonium hydroxide solution thereto at a uniform rate. The addition time is 0.5 min, and the final pH of the reaction system is 9.5. React at 25 °C for 10 h, and obtain polystyrene microsphere@polysiloxane core-shell composite after washing and drying (Step S13);

[0074] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composite with 100 g of acetylene black evenly and put them into a tube furnace. Set the nitrogen flow rate to 300 mL / min. Under a nitrogen atmosphere, heat to 400 °C at a rate of 1 °C / min and hold for 3 h;

[0075] Step S3: Switch the gas in the tube furnace to air, set the air flow rate to 300 mL / min. Under an air atmosphere, heat to 1200 °C at a rate of 10 °C / min, hold the particles at 1200 °C for 1 h to remove the carbon on the particle surface and densify the particle surface, and obtain a kind of surface-rough hollow silica particles.

[0076] Example 4

[0077] Step S1: Add 5000 g of water, 1 g of polyether F127, and 100 g of polystyrene microspheres with a particle size of 4.5 μm into a reactor to prepare a uniform emulsion (Step S11); add 5000 g of water and 400 g of methyltrimethoxysilane into another reactor, stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add a 25% ammonia water solution thereto at a uniform rate. The addition time is 60 min, and the final pH of the reaction system is 8. React at 25 °C for 10 h, and obtain polystyrene microsphere@polysiloxane core-shell composite after washing and drying (Step S13);

[0078] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composite with 400 g of acetylene black evenly and put them into a tube furnace. Set the nitrogen flow rate to 300 mL / min. Under a nitrogen atmosphere, heat to 650 °C at a rate of 1 °C / min and hold for 10 h;

[0079] Step S3: Switch the gas in the tubular furnace to air, set the air flow rate to 300 mL / min, under an air atmosphere, heat it to 900 °C at a rate of 5 °C / min, keep the particles at 900 °C for 10 h to remove the carbon on the particle surface and densify the particle surface, obtaining a kind of surface-rough hollow silica particles.

[0080] Example 5

[0081] Step S1: Add 5000 g of water, 1 g of polyvinylpyrrolidone, and 100 g of polystyrene microspheres with a particle size of 1 μm into a reactor to prepare a uniform emulsion (Step S11); add 5000 g of water and 300 g of methyltrimethoxysilane into another reactor, stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add an ammonia water solution with a concentration of 25% thereto at a uniform speed, the addition time is 60 min, the final pH of the reaction system is 8.5, react at 25 °C for 10 h, and obtain polystyrene microsphere@polysiloxane core-shell composites after washing and drying (Step S13);

[0082] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composites with 10 g of graphite evenly and put them into the tubular furnace, set the nitrogen flow rate to 300 mL / min, under a nitrogen atmosphere, heat it to 350 °C at a rate of 1 °C / min and keep it for 10 h;

[0083] Step S3: Switch the gas in the tubular furnace to air, set the air flow rate to 300 mL / min, under an air atmosphere, heat it to 850 °C at a rate of 8 °C / min, keep the particles at 850 °C for 10 h to remove the carbon on the particle surface and densify the particle surface, obtaining a kind of surface-rough hollow silica particles.

[0084] Example 6

[0085] Step S1: Add 5000 g of water, 1 g of polyvinylpyrrolidone, and 100 g of polystyrene microspheres with a particle size of 1 μm into a reactor to prepare a uniform emulsion (Step S11); add 5000 g of water and 300 g of methyltrimethoxysilane into another reactor, stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add a 25% tetramethylammonium hydroxide solution thereto at a uniform speed, the addition time is 60 min, the final pH of the reaction system is 11, react at 25 °C for 10 h, and obtain polystyrene microsphere@polysiloxane core-shell composites after washing and drying (Step S13);

[0086] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composite with 10 g of graphite evenly and put them into a tube furnace. Set the nitrogen flow rate to 300 mL / min. Under a nitrogen atmosphere, heat it to 250 °C at a rate of 1 °C / min and keep it for 10 h;

[0087] Step S3: Switch the gas in the tube furnace to air. Set the air flow rate to 300 mL / min. Under an air atmosphere, heat it to 900 °C at a rate of 5 °C / min, keep the particles at 900 °C for 10 h to remove the carbon on the particle surface and densify the particle surface, obtaining a kind of surface-rough hollow silica particles.

[0088] Example 7

[0089] Step S1: Add 5000 g of water, 1 g of polyvinylpyrrolidone and 100 g of polystyrene microspheres with a particle size of 1 μm into a reactor to prepare a uniform emulsion (Step S11); add 5000 g of water, 210 g of methyltrimethoxysilane and 90 g of dimethyldimethoxysilane into another reactor, stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add 25% tetramethylammonium hydroxide solution into it at a uniform speed. The addition time is 60 min, and the final pH of the reaction system is 9.5. React at 25 °C for 10 h, and obtain polystyrene microsphere@polysiloxane core-shell composite after washing and drying (Step S13);

[0090] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composite with 10 g of graphite evenly and put them into a tube furnace. Set the nitrogen flow rate to 300 mL / min. Under a nitrogen atmosphere, heat it to 250 °C at a rate of 1 °C / min and keep it for 10 h;

[0091] Step S3: Switch the gas in the tube furnace to air. Set the air flow rate to 300 mL / min. Under an air atmosphere, heat it to 800 °C at a rate of 5 °C / min, keep the particles at 800 °C for 12 h to remove the carbon on the particle surface and densify the particle surface, obtaining a kind of surface-rough hollow silica particles.

[0092] Example 8

[0093] Step S1: Add 5000 g of water, 1 g of polyvinylpyrrolidone, and 100 g of polystyrene microspheres with a particle size of 1 μm into a reactor to prepare a uniform emulsion (Step S11); add 5000 g of water, 270 g of methyltrimethoxysilane, 15 g of tetramethoxysilane, and 15 g of dimethyldimethoxysilane into another reactor, stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add a 25% solution of tetramethylammonium hydroxide thereto at a uniform rate. The addition time is 60 min, and the final pH of the reaction system is 8.5. React at 25 °C for 10 h, and obtain polystyrene microsphere@polysiloxane core-shell composites after washing and drying (Step S13);

[0094] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composites and 10 g of graphite evenly and put them into a tubular furnace. Set the nitrogen flow rate to 300 mL / min. Under a nitrogen atmosphere, heat to 250 °C at a rate of 1 °C / min and hold for 10 h;

[0095] Step S3: Switch the gas in the tubular furnace to air, set the air flow rate to 300 mL / min, heat to 850 °C at a rate of 5 °C / min under an air atmosphere, hold the particles at 850 °C for 10 h to remove the carbon on the particle surface and densify the particle surface, and obtain a kind of hollow silica particles with a rough surface.

[0096] Example 9

[0097] Step S1: Add 5000 g of water, 1 g of polyvinylpyrrolidone, and 100 g of polystyrene microspheres with a particle size of 600 nm into a reactor to prepare a uniform emulsion (Step S11); add 5000 g of water and 400 g of methyltrimethoxysilane into another reactor, stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add a 25% solution of tetramethylammonium hydroxide thereto at a uniform rate. The addition time is 50 min, and the final pH of the reaction system is 9. React at 25 °C for 10 h (Step S13); then add 400 g of methyltrimethoxysilane to the reaction system and react at 25 °C for 2 h, and obtain polystyrene microsphere@polysiloxane core-shell composites after washing and drying;

[0098] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composites and 5 g of acetylene black evenly and put them into a tubular furnace. Set the nitrogen flow rate to 300 mL / min. Under a nitrogen atmosphere, heat to 550 °C at a rate of 1 °C / min and hold for 8 h;

[0099] Step S3: Switch the gas in the tubular furnace to air, set the air flow rate to 300 mL / min, and under an air atmosphere, heat it to 1000 °C at a rate of 0.5 °C / min, keep the particles at 1000 °C for 1 h to remove the carbon on the particle surface and densify the particle surface, thereby obtaining a kind of surface-rough hollow silica particles.

[0100] Example 10

[0101] Step S1: Add 5000 g of water, 1 g of polyvinylpyrrolidone, and 100 g of polystyrene microspheres with a particle size of 600 nm into a reactor to prepare a uniform emulsion (Step S11); add 5000 g of water and 5200 g of methyltrimethoxysilane into another reactor, stir at 25 °C for 2 h for hydrolysis (Step S12); then mix the polymer emulsion and the hydrolysis product solution, and then add 25% tetramethylammonium hydroxide solution thereto at a uniform speed. The addition time is 50 min, and the final pH of the reaction system is 9. React at 25 °C for 10 h, and obtain polystyrene microsphere@polysiloxane core-shell composites after washing and drying (Step S13);

[0102] Step S2: Mix 100 g of polystyrene microsphere@polysiloxane core-shell composites with 5 g of acetylene black evenly and put them into a tubular furnace. Set the nitrogen flow rate to 300 mL / min. Under a nitrogen atmosphere, heat it to 550 °C at a rate of 1 °C / min and keep it for 8 h;

[0103] Step S3: Switch the gas in the tubular furnace to air, set the air flow rate to 300 mL / min, and under an air atmosphere, heat it to 1000 °C at a rate of 0.5 °C / min, keep the particles at 1000 °C for 1 h to remove the carbon on the particle surface and densify the particle surface, thereby obtaining a kind of surface-rough hollow silica particles.

[0104] Comparative Example 1

[0105] The difference from Example 1 is that the uniform addition time of the tetramethylammonium hydroxide solution in Step S13 is 0.33 min. Others are the same as Example 1.

[0106] Comparative Example 2

[0107] The difference from Example 1 is that in Step S12, the alkali solution is first added to the emulsion prepared in Step S11, and then the hydrolysis solution of methyltrimethoxysilane is added to the above mixture. The final pH of the solution is 9.5, and it reacts at 25 °C for 10 h. After washing and drying, polystyrene microsphere@polysiloxane core-shell composites are obtained.

[0108] Comparative Example 3

[0109] The difference from Example 1 lies in that: the heat treatment temperature in Steps S2 to S3 is 1600 °C. Others are the same as in Example 1.

[0110] Comparative Example 4

[0111] The difference from Example 1 lies in that: acetylene black was not added during the heat treatment process in Steps S2 to S3. Others are the same as in Example 1.

[0112] Comparative Example 5

[0113] The difference from Example 1 lies in that: methyltrimethoxysilane was replaced with tetraethyl orthosilicate in Step S1. Others are the same as in Example 1.

[0114] The particles prepared in Examples 2 - 9 are all of hollow structure. Figure 7 The SEM photographs of the particles prepared in Comparative Example 1 are shown. It can be seen from the photographs that in addition to the particles with hollow structure, the particles also contain self - aggregated polysiloxane spheres (non - hollow structure). The particles prepared in Comparative Example 2 also contain self - aggregated polysiloxane spheres. In Comparative Example 3, the heat treatment temperature was 1600 °C, and the morphology of the hollow particles changed and agglomerated into large chunks. In Comparative Example 4, acetylene black was not added during the heat treatment process, and the finally formed hollow particles agglomerated. The test performances of the hollow silica particles prepared in Examples 1 - 9 and Comparative Examples 1 - 5 are shown in Table 1. In Table 1, the measured values shown in Comparative Example 1, Comparative Example 2 and Comparative Example 4 were obtained from the measurement of hollow particles and non - hollow particles. Hollow - structured particles could not be obtained in Comparative Example 3, so there is no relevant data in the table.

[0115] Table 1

[0116]

[0117]

[0118] From the test data of the particles prepared in Examples 1 - 9 in the table, it can be seen that the hollow silica particles of the present invention have low water absorption capacity, are suitable for use as packaging fillers for semiconductor devices, and can reduce dielectric loss. Moreover, when added as a filler in a resin, it has good fluidity and high binding force with the resin.

[0119] From the test data of Examples 1 - 9, it can be seen that the water content is proportional to the specific surface area, and the larger the specific surface area, the higher the water content.

[0120] From the test data of Examples 1 and 2, and Examples 5 - 8, it can be seen that when the average maximum diameter of the particles is the same, the number of peeled particles combined with the resin is inversely proportional to the average diameter of the nano - protruding particles. From the test data of Examples 2 and 5, it can be seen that when the average diameter of the nano - protruding particles is the same, the number of peeled particles combined with the resin is proportional to the average maximum diameter of the particles.

[0121] From the test data of Examples 5 to 8, it can be seen that when the average maximum diameter of the particles is the same, the average diameter of the nano-protrusion particles is proportional to the pH value of the system, and the specific surface area increases with the increase of the average diameter of the nano-protrusion particles.

[0122] From the test data of Examples 4 and 6, and Examples 1 and 9, it can be seen that when the average diameter of the nano-protrusion particles is the same, the average maximum diameter of the particles is inversely proportional to the specific surface area.

[0123] From the test data of Examples 5 to 8, it can be seen that when the average maximum diameter of the particles is the same, the average diameter of the nano-protrusion particles is proportional to the viscosity. From the test data of Examples 4 and 6, it can be seen that when the average diameter of the nano-protrusion particles is the same, the average maximum diameter of the particles is inversely proportional to the viscosity.

[0124] The average maximum diameter (μm) of the hollow-structured particles obtained in Comparative Example 1 is smaller than the maximum average diameter of the hollow particles obtained in Example 1. This also shows that the polyorganosilicate formed by condensation in Comparative Example 1 was not completely coated on the surface of the polymer microspheres, but self-polymerized to form small spheres. This is the same as Figure 7 the results shown. It can be thus demonstrated that the addition method of the alkali solution (tetramethylammonium hydroxide solution) is crucial for the formation of the hollow structure. When the tetramethylammonium hydroxide solution is added to the system, methyltrimethoxysilane tends to grow on the surface of the polystyrene microspheres. When the tetramethylammonium hydroxide solution is rapidly added to the system, methyltrimethoxysilane is more prone to self-polymerize into particles. Therefore, there are many self-polymerized polysiloxane particles in the system.

[0125] Comparing Example 1 and Comparative Example 2, in Comparative Example 2, the alkali solution was added first and then methyltrimethoxysilane, resulting in a high pH value in the system at the beginning, and self-polymerized small spheres were easily formed in the system. The average maximum diameter (μm) of the particles in the table is for partially successfully coated core-shell microspheres, and the average diameter of the nano-protrusion particles is increased compared to Example 1.

[0126] From Comparative Example 5, it can be seen that when the silicon source was replaced from methyltrimethoxysilane with tetraethyl orthosilicate, due to the different hydrolysis rates, the average diameter of the nano-protrusion particles decreased, and the specific surface area and water content increased. And there are cracks on the particle surface, so the specific surface area is larger and the water absorption capacity is stronger. When used as a packaging material for semiconductor devices, it will cause a large dielectric loss. Compared with the data of Examples 1-10, it can be proved that the particles prepared by using a silicon source precursor capable of forming a silicon source precursor with a main chain of T units are more suitable as a packaging material for semiconductor devices than the hollow particles obtained from other silicon source precursors.

[0127] In Comparative Example 3, the heat treatment temperature was 1600 °C, and the morphology of the hollow particles changed and agglomerated into large chunks, so there is no relevant comparison data in the table.

[0128] In Comparative Example 4, acetylene black was not added during the heat treatment process, and the finally formed hollow particles were prone to agglomeration, resulting in a small content of the particles with a hollow structure prepared.

[0129] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification in order to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A hollow silica particle, characterized in that: The ratio of the hollow area of ​​the hollow silica particles to the total area of ​​the particles in the transmission electron microscope photograph is 10% to 96%; The average maximum diameter of the hollow silica particles is 100nm to 10μm; the shell layer of the hollow silica particles is an accumulation of nanoparticles, the average diameter of the nano-protrusion particles in the shell layer is 4 to 100nm, and the ratio of the average diameter of the nano-protrusion particles to the average maximum diameter of the hollow silica particles is between 1 / 2500 and 1 / 5.

2. The hollow silica particles according to claim 1, characterized in that The ratio of the hollow area of ​​the hollow silica particles to the total area of ​​the particles in the transmission electron microscope photograph is 20% to 80%, preferably 30% to 70%; The average maximum diameter of the hollow silica particles is 200 nm to 9 μm, preferably 300 nm to 8 μm; The shell layer of the hollow silica particles is an accumulation of nanoparticles, the average diameter of the nano-protrusion particles in the shell layer is 5 to 80 nm, and the ratio of the average diameter of the nano-protrusion particles to the average maximum diameter of the hollow silica particles is between 1 / 1800 and 1 / 5; preferably, the average diameter of the nano-protrusion particles is 5 to 60 nm, and the ratio of the average diameter of the nano-protrusion particles to the average maximum diameter of the hollow silica particles is between 1 / 1600 and 1 / 5.

3. The hollow silica particles according to claim 1, characterized in that The BET specific surface area of ​​the hollow silica particles is 50 m 2 / g or less; preferably 10 to 20 m 2 / g.

4. The hollow silica particles according to any one of claims 1 to 3, characterized in that Under the environmental conditions of 25° C. and 50% RH, the water content of the hollow silica particles after being left for 48 hours is not higher than 2800 ppm; preferably, not higher than 1500 ppm.

5. A method for preparing hollow silica particles according to any one of claims 1 to 4, characterized in that: include: S1, coating the surface of the polymer particles with a first polysiloxane to form a first particle, wherein the molar content of the polysiloxane with a main chain of T units in the first polysiloxane is greater than 70%, and the T units are R1SiO 3 / 2 , R1 is a hydrocarbon group having 1 to 16 carbon atoms; S2, mixing the carbon material with the first particles, and heat treating the mixture at 250-650° C. in an inert gas atmosphere to thermally decompose the polymer particles into carbon to form second particles; S3, calcining the second particles at 800-1200° C. in an oxygen-containing gas atmosphere.

6. The preparation method according to claim 5, characterized in that: The polymer particles are made of one or more of polystyrene, polymethyl methacrylate, polymethyl acrylate, phenol resin, melamine resin, polyurethane, and epoxy resin; and / or The particle size of the polymer particles is 80 nm to 9 μm.

7. The preparation method according to claim 5, characterized in that: Forming the first particles in the step S1 includes: S11, firstly preparing a dispersion liquid by mixing an oxygen-containing nonionic surfactant, water and the polymer particles; S12, mixing water and the first silicon source precursor to form a hydrolyzate solution; S13, after mixing the dispersion and the hydrolyzate solution, adding alkali solution so that the final pH of the reaction system is 8 to 11, and reacting for 1 to 10 hours; Wherein, the mass ratio of the polymer particles, the oxygen-containing nonionic surfactant and water is 1:0.1-0.01:50-200; Wherein, the mass ratio of the polymer particles, the first silicon source precursor and water is 1:1-8:50-200.

8. The preparation method according to claim 7, characterized in that: Adding a second silicon source precursor after step S13; The mass ratio of the polymer particles to the second silicon source precursor is 1:1-8, the second silicon source precursor is hydrolyzed to form a second polysiloxane that is coated on the outer surface of the first polysiloxane, and the molar content of the polysiloxane with T units as the main chain in the second polysiloxane is above 70%.

9. The preparation method according to claim 7 or 8, characterized in that: The oxygen-containing nonionic surfactant is polyvinyl pyrrolidone, polyether P123, polyether F127; and / or The alkali solution is an ammonia solution with a mass concentration of 25% to 28%, a tetramethylammonium hydroxide solution with a mass concentration of 25% to 28%, a sodium hydroxide solution with a mass concentration of 1% to 10%, or a potassium hydroxide solution with a mass concentration of 1% to 10%; and / or In the step S13, the alkali solution is added to the reaction system at a uniform speed within 0.5 min-1 h.

10. The preparation method according to claim 5, characterized in that: The carbon material is one or more of graphite, acetylene black, diamond, fullerene, and carbene; and / or The mass ratio of the first particles to the carbon material is 1:0.05-5.

11. The preparation method according to claim 5, characterized in that: In the step S2, the heat treatment is to increase the temperature to 250-650°C at a heating rate of 0.5-10°C / min and keep the temperature for 3-20h; The oxygen mass content in the inert gas atmosphere is less than 10%, and the flow rate of the inert gas is 30-1000 mL / min.

12. The preparation method according to claim 5, characterized in that: In the step S3, the heat treatment is to heat the temperature to 800-1200°C at a heating rate of 0.5-10°C / min and keep the temperature for 1-20h; the oxygen content of the oxygen-containing gas atmosphere is 10%-100%, and the flow rate of the oxygen-containing gas is 30-1000mL / min.

13. The preparation method according to claim 8, characterized in that: The first silicon source precursor and the second silicon source precursor are independently hydrocarbon trialkoxysilane or hydrocarbon trichlorosilane; preferably, one or both of methyltrimethoxysilane and methyltrichlorosilane.

14. Use of the hollow silica particles according to any one of claims 1 to 4, or the hollow silica particles prepared by the preparation method according to any one of claims 5 to 13 as semiconductor packaging materials, substrate materials, loaded catalysis, drug loading or cosmetics.

Images