Submicron surface modified angular silica powder as well as preparation method and application thereof

Abstract

The invention relates to the technical field of silicon micro-powder, and provides submicron surface modified angular silicon micro-powder as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing angular fused silica powder slurry through two-stage grinding of coarse grinding and fine grinding, then modifying the angular fused silica powder through two-step wet modification, and finally obtaining the submicron surface modified angular silica powder through spray drying and depolymerization. The particle size of the silica powder can be accurately controlled through two-stage grinding, and the grinding efficiency is improved; a gradient coating layer is formed through two-step wet process modification, so that the surface modification uniformity can be effectively improved, the problem of insufficient coating at corners of angular particles is solved, and the compatibility of silica powder and an organic matrix is enhanced. Results of the embodiment show that the submicron surface modified angular silica powder prepared by the method has excellent indexes and can meet the use requirements of HDI copper-clad plates.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon powder, in particular to a submicron surface modified angular silicon powder and a preparation method and application thereof. BACKGROUND

[0002] As an important inorganic filler, silicon powder is widely used in electronic packaging materials, copper-clad plates and other fields due to its excellent insulation, thermal conductivity and chemical stability. According to the particle morphology, silicon powder can be generally divided into angular silicon powder and spherical silicon powder. Among them, angular silicon powder has a strong mechanical engagement ability with the resin matrix due to its angular shape, and has a lower production cost, and is widely used in the field of copper-clad plates.

[0003] With the rapid development of the electronic industry, high-density interconnection (HDI) copper-clad plates, as the core substrate of high-end electronic components, have put forward more stringent requirements on the performance of fillers. When silicon powder is mixed with resin, there are problems of poor compatibility and difficult dispersion, which affects the reliability and stability of the product. In order to improve the interface bonding of silicon powder and resin and improve its application performance, it is generally necessary to modify the surface of silicon powder. However, submicron angular silicon powder has an irregular angular structure, which is prone to uneven surface modification, especially the angular particles, which are prone to insufficient coating at the angular part, resulting in poor dispersion of the particles in the polymer matrix, affecting the key performance of the material such as melt viscosity, and making it difficult to meet the use requirements of high-end fields such as HDI copper-clad plates. SUMMARY

[0004] Therefore, the present application provides a submicron surface modified angular silicon powder and a preparation method and application thereof. The method provided by the present application can solve the problems of uneven surface modification and insufficient coating at the angular part of the angular silicon powder in the prior art, obtain a submicron surface modified angular silicon powder with excellent performance, and meet the use requirements of high-end fields such as HDI copper-clad plates.

[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions: A preparation method of a submicron surface modified angular silicon powder, comprising the following steps: wet grinding the angular fused silicon powder to obtain a submicron angular fused silicon powder slurry; the wet grinding comprises sequentially performing coarse grinding and fine grinding; mixing the submicron angular fused silicon powder slurry and a first modifier alcohol solution to perform a first modification reaction, to obtain a first modified slurry; the first modifier in the first modifier alcohol solution is hexamethyldisilazane; mixing the first modified slurry and a second modifier alcohol solution to perform a second modification reaction, to obtain a second modified slurry; the second modifier in the second modifier alcohol solution is an unsaturated alkoxysilane. The second modified slurry is sequentially subjected to spray drying and depolymerization to obtain the sub-micron surface modified angular silicon micro powder.

[0006] Preferably, the D50 of the angular fused silicon micro powder is 10-20 microns. 50 The particle size is 100-120 microns.

[0007] Preferably, the solvent used in the wet grinding is water; the conditions of the coarse grinding include that the grinding medium is zirconium beads with a diameter of 1.5-2 mm, the rotation speed is 900-1000 r / min, and the grinding time is 1-2 h; the conditions of the fine grinding include that the grinding medium is zirconium beads with a diameter of 0.3-0.5 mm, the rotation speed is 1000-1200 r / min, and the grinding time is 2-4 h. The D50 of the sub-micron angular fused silicon micro powder in the sub-micron angular fused silicon micro powder slurry is 0.4-0.8 microns. 50 The particle size is 0.4-0.8 microns.

[0008] Preferably, the amount of the first modifier is 0.2-0.5% of the mass of the angular fused silicon micro powder; the mass ratio of the first modifier to alcohol in the first modifier alcohol solution is 1:0.5-1; the temperature of the first modification reaction is 40-60℃, the time is 0.5-1 h, and the stirring speed is 800-1000 r / min.

[0009] Preferably, the unsaturated alkoxysilane includes one or more of vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloyloxypropyltrimethoxysilane. The amount of the second modifier is 1-2% of the mass of the sub-micron angular fused silicon micro powder; the mass ratio of the second modifier to alcohol in the second modifier alcohol solution is 1:0.5-1; the temperature of the second modification reaction is 40-60℃, the time is 0.5-1 h, and the stirring speed is 800-1000 r / min.

[0010] Preferably, the inlet temperature of the spray drying is 200-280℃, and the outlet temperature is 100-130℃.

[0011] Preferably, after the depolymerization, the obtained depolymerized powder is further classified to obtain the sub-micron surface modified angular silicon micro powder.

[0012] The application also provides a sub-micron surface modified angular silicon micro powder prepared by the preparation method described in the above scheme, wherein the D50 of the sub-micron surface modified angular silicon micro powder is 0.4-0.8 microns. 50 The particle size is 0.4-0.8 microns, and the D 100 The particle size is less than 5 microns, the specific surface area is 6-10 m 2 / g.

[0013] Preferably, the sub-micron surface-modified angular silicon micropowder has a SiO2 content of >99.0 wt%, a carbon content of 0.4-1.0 wt%, and an oil absorption value of 50-60 g / 100 g.

[0014] The application also provides the use of the sub-micron surface-modified angular silicon micropowder described in the above scheme in a copper-clad plate.

[0015] The application provides a preparation method of a sub-micron surface-modified angular silicon micropowder, which comprises the following steps: wet grinding angular fused silicon micropowder to obtain a sub-micron angular fused silicon micropowder slurry; the wet grinding comprises sequentially performing coarse grinding and fine grinding; mixing the sub-micron angular fused silicon micropowder slurry and a first modifier alcohol solution to perform a first modification reaction, to obtain a first modified slurry; the first modifier in the first modifier alcohol solution is hexamethyldisilazane; mixing the first modified slurry and a second modifier alcohol solution to perform a second modification reaction, to obtain a second modified slurry; the second modifier in the second modifier alcohol solution is an unsaturated alkoxysilane; and sequentially performing spray drying and depolymerization on the second modified slurry, to obtain the sub-micron surface-modified angular silicon micropowder. The application can precisely control the particle size of the silicon micropowder and improve the grinding efficiency by two-stage grinding of coarse grinding and fine grinding. The application can effectively improve the uniformity of surface modification by forming a gradient coating layer through two-step wet modification, solves the problem of insufficient coating at the corners of the angular particles, and enhances the compatibility of the silicon micropowder with an organic matrix. Meanwhile, the application uses hexamethyldisilazane as the modifier in the first-step wet modification, and the hexamethyldisilazane has high reactivity and can quickly react with a large number of hydroxyl groups on the surface of the silicon micropowder, thereby efficiently reducing the surface energy and inhibiting agglomeration. The second-step wet modification uses an unsaturated alkoxysilane as the modifier, which can chemically cross-link with a resin or other matrix used in the production process of an HDI copper-clad plate, thereby significantly improving the melt viscosity of the material. The application dries the modified slurry by spray drying, and compared with flash drying, the powder after spray drying is spherical or quasi-spherical, has uniform particle size and good flowability, and the drying process is mild and does not easily damage the surface modification layer, so it is easy to restore to angular silicon micropowder after being dispersed by depolymerization. However, the powder after flash drying is prone to agglomeration, is difficult to disperse, and the corners or surface coating layer of the angular particles may be damaged in the depolymerization process.

[0016] The results of the examples show that the sub-micron surface-modified angular silicon micropowder prepared by the application has excellent indexes (D 50 : 0.4-0.8 μm, D 100 < 5 μm, specific surface area 6-10 m 2 / g, SiO2 content >99.0 wt%, carbon content 0.4-1.0 wt%). The resin material added with the sub-micron surface-modified angular silicon micropowder of the application has lower melt viscosity and good flowability, can be uniformly coated on the surface of a copper foil, and can meet the use requirements of an HDI copper-clad plate. DETAILED DESCRIPTION

[0017] The application provides a preparation method of submicron surface modified angular silicon micro powder, comprising the following steps: wet grinding the angular fused silicon micro powder to obtain a submicron angular fused silicon micro powder slurry; the wet grinding comprises sequentially performing coarse grinding and fine grinding; mixing the submicron angular fused silicon micro powder slurry and a first modifier alcohol solution to perform a first modification reaction, to obtain a first modified slurry; the first modifier in the first modifier alcohol solution is hexamethyldisilazane; mixing the first modified slurry and a second modifier alcohol solution to perform a second modification reaction, to obtain a second modified slurry; the second modifier in the second modifier alcohol solution is an unsaturated alkoxysilane; sequentially performing spray drying and depolymerization on the second modified slurry to obtain the submicron surface modified angular silicon micro powder.

[0018] The application performs wet grinding on the angular fused silicon micro powder to obtain a submicron angular fused silicon micro powder slurry. In the application, the D 50 The particle size is preferably 100-120 μm; the wet grinding comprises sequentially performing coarse grinding and fine grinding; the solvent used in the wet grinding is preferably water, and the mass ratio of the angular fused silicon micro powder to water is preferably 1:2; the wet grinding is preferably performed in a sand mill.

[0019] In the application, the conditions of the coarse grinding preferably comprise that the grinding medium is zirconium beads with a diameter of 1.5-2 mm, the rotating speed is 900-1000 r / min, and the grinding time is 1-2 h, and specifically, the grinding time can be 1 h, 1.5 h or 2 h; the conditions of the fine grinding preferably comprise that the grinding medium is zirconium beads with a diameter of 0.3-0.5 mm, the rotating speed is 1000-1200 r / min, and the grinding time is 2-4 h, and specifically, the grinding time can be 2 h, 2.5 h, 3 h or 4 h. Through two-stage grinding, the application can precisely control the particle size of the submicron angular fused silicon micro powder and improve the grinding efficiency.

[0020] In the application, the particle size of the submicron angular fused silicon micro powder in the submicron angular fused silicon micro powder slurry is preferably 0.4-0.8 μm.

[0021] After obtaining the sub-micron angular fused silica micro-powder slurry, the sub-micron angular fused silica micro-powder slurry and a first modifier alcohol solution are mixed to perform a first modification reaction to obtain a first modified slurry. In the present application, the components of the first modifier alcohol solution include a first modifier and alcohol; the first modifier is hexamethyldisilazane; the alcohol is ethanol; the mass ratio of the first modifier and alcohol is preferably 1:0.5-1; in specific embodiments of the present application, the first modifier and alcohol are preferably stirred and mixed for 30-60 min to obtain the first modifier alcohol solution; the amount of the first modifier is preferably 0.2-0.5% of the mass of the angular fused silica micro-powder, and can be specifically 0.2%, 0.3% or 0.5%; the temperature of the first modification reaction is preferably 40-60°C, and can be specifically 40°C, 50°C or 60°C; the time of the first modification reaction is preferably 0.5-1 h, and the stirring speed is preferably 800-1000 r / min, and can be specifically 900 r / min; the first modifier alcohol solution is preferably slowly added to the sub-micron angular fused silica micro-powder slurry, and in specific embodiments of the present application, a peristaltic pump can be used to add the first modifier alcohol solution to the sub-micron angular fused silica micro-powder slurry, and the time of the first modification reaction is counted from the completion of the addition of the first modifier alcohol solution.

[0022] After obtaining the first modified slurry, the first modified slurry and a second modifier alcohol solution are mixed to perform a second modification reaction to obtain a second modified slurry. In the present application, the components of the second modifier alcohol solution include a second modifier and alcohol; the second modifier is an unsaturated alkoxysilane, and the unsaturated alkoxysilane preferably includes one or more of vinyltrimethoxysilane, vinyltriethoxysilane and methacryloyloxypropyltrimethoxysilane; the alcohol is preferably ethanol; the amount of the second modifier is preferably 1-2% of the mass of the angular fused silica micro-powder, and can be specifically 1%, 1.5% or 2%; the mass ratio of the second modifier and alcohol is preferably 1:0.5-1, and can be specifically 1:1; in specific embodiments of the present application, the second modifier and alcohol are preferably stirred and mixed for 30-60 min to obtain the second modifier alcohol solution; the temperature of the second modification reaction is preferably 40-60°C, and can be specifically 40°C, 50°C or 60°C; the time of the second modification reaction is preferably 0.5-1 h, and the stirring speed is preferably 800-1000 r / min, and can be specifically 900 r / min. The second modifier alcohol solution is preferably slowly added to the first modified slurry, and in specific embodiments of the present application, a peristaltic pump can be used to add the second modifier alcohol solution to the first modified slurry, and the time of the second modification reaction is counted from the completion of the addition of the second modifier alcohol solution.

[0023] The present application modifies by two steps of wet method, the first step adds hexamethyldisilazane, because hexamethyldisilazane has high reactivity, can quickly react with a large number of hydroxyl groups on the surface of silicon powder, efficiently reduces the surface energy and inhibits agglomeration; the second step adds unsaturated alkoxysilane, which can chemically crosslink with the resin matrix in the production process of HDI copper clad plate, and can significantly improve the melt viscosity of the material.

[0024] After obtaining the second modified slurry, the present application sprays and dries the second modified slurry in sequence, and obtains the submicron surface modified angular silicon powder; the inlet temperature of the spray drying is preferably 200-280℃, and specifically can be 230℃, and the outlet temperature is preferably 100-130℃, and specifically can be 100℃.

[0025] In the present application, the depolymerization preferably uses mechanical impact grinding; after the depolymerization, preferably, the obtained depolymerization powder is further classified; the classification preferably uses airflow classification or screening, and specifically can use an airflow classifier or a screening machine.

[0026] The present application also provides the submicron surface modified angular silicon powder prepared by the preparation method described in the above scheme, and the D 50 particle size is 0.4-0.8μm, and the D 100 particle size is <5μm, the specific surface area is 6-10m 2 / g.

[0027] In the present application, the SiO2 content of the submicron surface modified angular silicon powder is >99.0wt%, the carbon content is 0.4-1.0wt%, and the oil absorption value is 50-60g / 100g.

[0028] The present application also provides the application of the submicron surface modified angular silicon powder described in the above scheme in a copper clad plate; the copper clad plate is specifically an HDI copper clad plate.

[0029] The technical solutions in the present application will be described clearly and completely in combination with the embodiments in the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0030] Example 1 Take 100kg D 50The angular fused silica micropowder with a particle size of 100 μm was mixed with 200 kg of deionized water, and was fed into a sand mill 1 (grinding medium: 1.5 mm zirconium beads, rotation speed: 1000 r / min) for coarse grinding for 1.5 h, and was then fed into a sand mill 2 (grinding medium: 0.5 mm zirconium beads, rotation speed: 1200 r / min) for fine grinding for 3 h, to obtain a submicron angular fused silica micropowder slurry with a particle size of about 0.5 μm.

[0031] The first modifier alcohol solution was obtained by mixing 0.3 kg of hexamethyldisilazane with 0.3 kg of ethanol for 45 min; the first modifier alcohol solution was added into the above-mentioned submicron angular fused silica micropowder slurry by using a peristaltic pump, and was reacted at 50°C and 900 r / min for 1 h, to obtain a first modified slurry.

[0032] The second modifier alcohol solution was obtained by mixing 1 kg of vinyltrimethoxysilane with 1 kg of ethanol for 45 min; the second modifier alcohol solution was added into the first modified slurry by using a peristaltic pump, and was reacted at 50°C and 900 r / min for 1 h, to obtain a second modified slurry.

[0033] The second modified slurry was subjected to spray drying (inlet temperature: 230°C, outlet temperature: 100°C), and then was subjected to mechanical impact grinding and depolymerization, and was sieved through a 200-mesh screen, to obtain a submicron surface-modified angular silica micropowder.

[0034] Example 2 100 kg of D 50 The angular fused silica micropowder with a particle size of 120 μm was mixed with 200 kg of deionized water, and was fed into a sand mill 1 (grinding medium: 2 mm zirconium beads, rotation speed: 900 r / min) for coarse grinding for 2 h, and was then fed into a sand mill 2 (grinding medium: 0.3 mm zirconium beads, rotation speed: 1200 r / min) for fine grinding for 2.5 h, to obtain a submicron angular fused silica micropowder slurry with a particle size of about 0.8 μm.

[0035] The first modifier alcohol solution was obtained by mixing 0.5 kg of hexamethyldisilazane with 0.5 kg of ethanol for 45 min; the first modifier alcohol solution was added into the above-mentioned submicron angular fused silica micropowder slurry by using a peristaltic pump, and was reacted at 40°C and 900 r / min for 1 h, to obtain a first modified slurry.

[0036] The second modifier alcohol solution was obtained by mixing 2 kg of vinyltrimethoxysilane with 2 kg of ethanol for 45 min; the second modifier alcohol solution was added into the first modified slurry by using a peristaltic pump, and was reacted at 40°C and 1000 r / min for 1 h, to obtain a second modified slurry.

[0037] The second modified slurry is spray dried (inlet temperature 280℃, outlet temperature 130℃), and then mechanically impact milled and depolymerized, and sieved to 200 mesh, to obtain the sub-micron surface modified angular silicon micro powder.

[0038] Example 3 Take 100 kg of D 50 The angular fused silicon micro powder with a particle size of 100 μm is mixed with 200 kg of deionized water, and then fed into a sand mill 1 (grinding medium is 1.5 mm zirconium beads, rotation speed is 1000 r / min) for coarse grinding for 1 h, and then fed into a sand mill 2 (grinding medium is 0.5 mm zirconium beads, rotation speed is 1200 r / min) for fine grinding for 3 h, to obtain a sub-micron angular fused silicon micro powder slurry with a particle size of about 0.5 μm.

[0039] The first modifier alcohol solution is obtained by mixing 0.2 kg of hexamethyldisilazane with 0.1 kg of ethanol for 45 min; the first modifier alcohol solution is added into the above-mentioned sub-micron angular fused silicon micro powder slurry using a peristaltic pump, and reacted at 60℃ and 900 r / min for 1 h, to obtain a first modified slurry.

[0040] The second modifier alcohol solution is obtained by mixing 1.5 kg of vinyltrimethoxysilane with 1.5 kg of ethanol for 45 min; the second modifier alcohol solution is added into the first modified slurry using a peristaltic pump, and reacted at 60℃ and 800 r / min for 1 h, to obtain a second modified slurry.

[0041] The second modified slurry is spray dried (inlet temperature 230℃, outlet temperature 100℃), and then mechanically impact milled and depolymerized, and sieved to 200 mesh, to obtain the sub-micron surface modified angular silicon micro powder.

[0042] Example 4 Take 100 kg of D 50 The angular fused silicon micro powder with a particle size of 100 μm is mixed with 200 kg of deionized water, and then fed into a sand mill 1 (grinding medium is 1.5 mm zirconium beads, rotation speed is 1000 r / min) for coarse grinding for 1.5 h, and then fed into a sand mill 2 (grinding medium is 0.5 mm zirconium beads, rotation speed is 1000 r / min) for fine grinding for 4 h, to obtain a sub-micron angular fused silicon micro powder slurry with a particle size of about 0.5 μm.

[0043] The first modifier alcohol solution is obtained by mixing 0.3 kg of hexamethyldisilazane with 0.3 kg of ethanol for 45 min; the first modifier alcohol solution is added into the above-mentioned sub-micron angular fused silicon micro powder slurry using a peristaltic pump, and reacted at 50℃ and 900 r / min for 1 h, to obtain a first modified slurry.

[0044] Mix 1 kg of methacryloxypropyltrimethoxysilane with 0.5 kg of ethanol for 45 min to obtain a second modifier alcohol solution; use a peristaltic pump to add the second modifier alcohol solution to the first modified slurry, and react at 50°C and 800 r / min for 0.5 h to obtain a second modified slurry.

[0045] Spray dry the second modified slurry (inlet temperature 230°C, outlet temperature 100°C), and then mechanically impact and grind to disaggregate, sieve through a 200-mesh screen to obtain submicron surface-modified angular silicon micropowder.

[0046] Comparative Example 1 Take 100 kg of D 50 Mix angular fused silicon micropowder with a particle size of 100 μm and 200 kg of deionized water, and feed into a sand mill 1 (grinding medium: 1.5 mm zirconium beads, rotation speed 1000 r / min) for coarse grinding for 1.5 h, and then feed into a sand mill 2 (grinding medium: 0.5 mm zirconium beads, rotation speed 1200 r / min) for fine grinding for 3 h to obtain submicron angular fused silicon micropowder slurry with a particle size of about 0.5 μm.

[0047] Mix 1 kg of vinyltrimethoxysilane with 1 kg of ethanol for 45 min to obtain a modifier alcohol solution, use a peristaltic pump to add the modifier alcohol solution to the submicron angular fused silicon micropowder slurry, and react at 50°C and 900 r / min for 1 h to obtain a modified slurry.

[0048] Spray dry the modified slurry (inlet temperature 230°C, outlet temperature 100°C), and then mechanically impact and grind to disaggregate, sieve through a 200-mesh screen to obtain submicron surface-modified angular silicon micropowder.

[0049] Comparative Example 2 Take 100 kg of D 50 Mix angular fused silicon micropowder with a particle size of 100 μm and 200 kg of deionized water, and feed into a sand mill (grinding medium: 0.5 mm zirconium beads, rotation speed 1200 r / min) for fine grinding for 8 h to obtain submicron angular fused silicon micropowder slurry with a particle size of about 0.5 μm.

[0050] Mix 0.3 kg of hexamethyldisilazane with 0.3 kg of ethanol for 45 min to obtain a first modifier alcohol solution; use a peristaltic pump to add the first modifier alcohol solution to the above submicron angular fused silicon micropowder slurry, and react at 50°C and 900 r / min for 1 h to obtain a first modified slurry.

[0051] Mix 1 kg of vinyl trimethoxysilane with 1 kg of ethanol for 45 min to obtain a second modifier alcohol solution; use a peristaltic pump to add the second modifier alcohol solution to the first modified slurry, and react at 50°C and 900 r / min for 1 h to obtain a second modified slurry.

[0052] Spray dry the second modified slurry (inlet temperature 230°C, outlet temperature 100°C), and then mechanically impact and disaggregate, and sieve through a 200-mesh screen to obtain submicron surface-modified angular silicon micropowder.

[0053] Comparative Example 3 Take 100 kg of D 50 Mix angular fused silicon micropowder with a particle size of 100 μm with 200 kg of deionized water, and feed into sand mill 1 (grinding medium: 1.5 mm zirconium beads, rotation speed 1000 r / min) for coarse grinding for 1.5 h, and then feed into sand mill 2 (grinding medium: 0.5 mm zirconium beads, rotation speed 1200 r / min) for fine grinding for 3 h to obtain submicron angular fused silicon micropowder slurry with a particle size of about 0.5 μm.

[0054] Spray dry the submicron angular fused silicon micropowder slurry (inlet temperature 230°C, outlet temperature 100°C), and then mechanically impact and disaggregate, and sieve through a 200-mesh screen to obtain submicron angular silicon micropowder.

[0055] Mix the submicron angular silicon micropowder and vinyl trimethoxysilane (amount: 1% of the mass of the submicron angular silicon micropowder) in a high-speed mixer, and mix at 110°C and 200 r / min for 0.5 h to modify, and then mechanically impact and disaggregate, and sieve through a 200-mesh screen to obtain submicron surface-modified angular silicon micropowder.

[0056] Comparative Example 4 Take 100 kg of D 50 Mix angular fused silicon micropowder with a particle size of 100 μm with 200 kg of deionized water, and feed into sand mill 1 (grinding medium: 1.5 mm zirconium beads, rotation speed 1000 r / min) for coarse grinding for 1.5 h, and then feed into sand mill 2 (grinding medium: 0.5 mm zirconium beads, rotation speed 1200 r / min) for fine grinding for 3 h to obtain submicron angular fused silicon micropowder slurry with a particle size of about 0.5 μm.

[0057] Slowly add a mixture of 0.3 kg of hexamethyldisilazane and 1 kg of vinyl trimethoxysilane (without adding ethanol) to the submicron angular fused silicon micropowder slurry using a peristaltic pump, and react at 50°C and 900 r / min for 1 h to obtain a modified slurry.

[0058] The modified slurry is spray dried (inlet temperature 230°C, outlet temperature 100°C), and then mechanically impact-milled and depolymerized, and sieved to 200 mesh, to obtain the sub-micron surface-modified angular silicon micro-powder.

[0059] Comparative Example 5 Take 100 kg of D 50 The angular fused silicon micro-powder with a particle size of 100 μm is mixed with 200 kg of deionized water, and then fed into a sand mill 1 (grinding medium is 1.5 mm zirconium beads, rotation speed is 1000 r / min) for coarse grinding for 1.5 h, and then fed into a sand mill 2 (grinding medium is 0.5 mm zirconium beads, rotation speed is 1200 r / min) for fine grinding for 3 h, to obtain a sub-micron angular fused silicon micro-powder slurry with a particle size of about 0.5 μm.

[0060] 1 kg of vinyl trimethoxysilane is added to the slurry, and reacted at 50°C and 900 r / min for 1 h to obtain a modified slurry.

[0061] The modified slurry is spray dried (inlet temperature 230°C, outlet temperature 100°C), and then mechanically impact-milled and depolymerized, and sieved to 200 mesh, to obtain the sub-micron surface-modified angular silicon micro-powder.

[0062] Comparative Example 6 Take 100 kg of D 50 The angular fused silicon micro-powder with a particle size of 100 μm is mixed with 200 kg of deionized water, and then fed into a sand mill 1 (grinding medium is 1.5 mm zirconium beads, rotation speed is 1000 r / min) for coarse grinding for 1.5 h, and then fed into a sand mill 2 (grinding medium is 0.5 mm zirconium beads, rotation speed is 1200 r / min) for fine grinding for 3 h, to obtain a sub-micron angular fused silicon micro-powder slurry with a particle size of about 0.5 μm.

[0063] The sub-micron angular fused silicon micro-powder slurry is spray dried (inlet temperature 230°C, outlet temperature 100°C), and then mechanically impact-milled and depolymerized, and sieved to 200 mesh, to obtain the sub-micron angular silicon micro-powder.

[0064] Hexamethyldisilazane is added to the sub-micron angular silicon micro-powder (amount is 0.3% of the mass of the sub-micron angular silicon micro-powder), and modified in a high-speed mixer (modification temperature is 110°C, rotation speed is 200 r / min, time is 0.5 h), and then vinyl trimethoxysilane is added (amount is 1% of the mass of the sub-micron angular silicon micro-powder) to modify (modification temperature is 110°C, rotation speed is 200 r / min, time is 0.5 h), and then mechanically impact-milled and depolymerized, and sieved to 200 mesh, to obtain the sub-micron surface-modified angular silicon micro-powder.

[0065] Comparative Example 7 Take 100 kg of D 50The angular fused silica micropowder with a particle size of 100 μm was mixed with 200 kg of deionized water, and then was fed into a sand mill 1 (the grinding medium was 1.5 mm zirconium beads, and the rotating speed was 1000 r / min) for coarse grinding for 1.5 h, and then was fed into a sand mill 2 (the grinding medium was 0.5 mm zirconium beads, and the rotating speed was 1200 r / min) for fine grinding for 3 h, so as to obtain the submicron angular fused silica micropowder slurry with a particle size of about 0.5 μm.

[0066] The submicron angular fused silica micropowder slurry was subjected to spray drying (the inlet temperature was 230℃, and the outlet temperature was 100℃), and then was subjected to mechanical impact grinding and disaggregation, and was sieved through a 200 mesh screen, so as to obtain the submicron angular silica micropowder.

[0067] The first modifier alcohol solution was prepared by mixing hexamethyldisilazane and ethanol at a mass ratio of 1:1 for 45 min, and the mass of the hexamethyldisilazane was 0.3% of the mass of the angular fused silica micropowder; the hexamethyldisilazane alcohol solution was added in a high-speed mixer for modification, the modification temperature was 120℃, the rotating speed was 200 r / min, and the time was 0.5 h.

[0068] The second modifier alcohol solution was prepared by mixing methacryloyloxypropyl trimethoxysilane and ethanol at a mass ratio of 1:1 for 45 min, and the mass of the methacryloyloxypropyl trimethoxysilane alcohol was 1% of the mass of the angular fused silica micropowder; the methacryloyloxypropyl trimethoxysilane alcohol solution was added in a high-speed mixer for modification, the modification temperature was 120℃, the rotating speed was 200 r / min, and the time was 0.5 h; and then the submicron surface-modified angular silica micropowder was obtained by mechanical impact grinding and disaggregation and sieving through a 200 mesh screen.

[0069] Performance test Basic performance test: the particle size (laser particle size analyzer), specific surface area (specific surface area analyzer), carbon content (carbon six analyzer), oil absorption value (DBP titration method) and SiO2 content of the submicron surface-modified angular silica micropowder prepared in Examples 1-4 and Comparative Examples 1-7 were tested, and the results are shown in Table 1.

[0070] Lowest viscosity test: the epoxy resin and the submicron surface-modified angular silica micropowder were mixed, and the lowest viscosity was detected by using a rheometer; the mass ratio of the epoxy resin was 70%, and the mass ratio of the submicron surface-modified angular silica micropowder was 30%; and the test results are shown in Table 1.

[0071] Table 1 Test results

[0072] According to the test results in Table 1, it can be seen that the submicron surface-modified angular silica micropowder D 50 The particle size is 0.4-0.8 μm, D 100The resin material containing the sub-micron surface modified angular silicon micropowder of the application has a particle size of less than 5 microns, a carbon content of 0.4-1.0 wt%, and a small specific surface area and oil absorption value, and has a lower melt viscosity and good fluidity, and can be uniformly coated on the surface of a copper foil, and can meet the use requirements of HDI copper-clad plates; in the comparative examples 1, 4 and 5, one-step wet modification is used, in the comparative examples 3, 6 and 7, the spray drying is performed before modification, the sub-micron surface modified angular silicon micropowder obtained has a large surface area and a high oil absorption value, and the melt viscosity of the material after being added into the resin is high; in the comparative example 2, primary grinding (fine grinding) is used, the grinding efficiency is low, the specific surface area of the product is increased, and the melt viscosity of the material after being added into the resin is increased.

[0073] The above results show that the method provided by the application can solve the problems of uneven surface modification and insufficient coating at the edges and corners of the angular silicon micropowder in the prior art, and obtain sub-micron angular silicon micropowder with excellent performance, which meets the use requirements of HDI copper-clad plates.

[0074] The above only describes the preferred embodiments of the application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the application, and these improvements and refinements should also be considered as the protection scope of the application.

Claims

1. A method for preparing submicron surface-modified angular silica powder, characterized in that, Includes the following steps: The angular fused silica micro powder is wet-milled to obtain a submicron angular fused silica micro powder slurry; the wet milling includes sequential coarse milling and fine milling. The submicron angular molten silica powder slurry is mixed with a first modifier alcohol solution to carry out a first modification reaction, thereby obtaining a first modified slurry; the first modifier in the first modifier alcohol solution is hexamethyldisilazane; The first modified slurry and the second modifier alcohol solution are mixed to carry out a second modification reaction to obtain a second modified slurry; the second modifier in the second modifier alcohol solution is an unsaturated alkoxysilane; The second modified slurry was sequentially spray-dried and depolymerized to obtain the submicron surface-modified angular silica powder.

2. The preparation method according to claim 1, characterized in that, The angular fused silica micropowder D 50 The particle size is 100~120μm.

3. The preparation method according to claim 1, characterized in that, The solvent used in the wet grinding process is water; the conditions for coarse grinding include: the grinding medium is zirconium beads with a diameter of 1.5~2mm, the rotation speed is 900~1000r / min, and the grinding time is 1~2h; the conditions for fine grinding include: the grinding medium is zirconium beads with a diameter of 0.3~0.5mm, the rotation speed is 1000~1200r / min, and the grinding time is 2~4h. The submicron angular fused silica powder slurry contains submicron angular fused silica powder with D... 50 The particle size is 0.4~0.8μm.

4. The preparation method according to claim 1, characterized in that, The amount of the first modifier is 0.2-0.5% of the mass of the angular fused silica powder; the mass ratio of the first modifier to the alcohol in the first modifier alcohol solution is 1:0.5-1; the temperature of the first modification reaction is 40-60℃, the time is 0.5-1h, and the stirring speed is 800-1000r / min.

5. The preparation method according to claim 1, characterized in that, The unsaturated alkoxysilanes include one or more of vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane; The amount of the second modifier is 1-2% of the mass of the angular fused silica powder; the mass ratio of the second modifier to the alcohol in the second modifier alcohol solution is 1:0.5-1; the temperature of the second modification reaction is 40-60℃, the time is 0.5-1h, and the stirring speed is 800-1000r / min.

6. The preparation method according to claim 1, characterized in that, The inlet temperature of the spray dryer is 200~280℃, and the outlet temperature is 100~130℃.

7. The preparation method according to claim 1 or 6, characterized in that, After depolymerization, the process further includes classifying the resulting depolymerized powder to obtain the submicron surface-modified angular silicon micropowder.

8. The submicron surface-modified angular silica powder prepared by the preparation method according to any one of claims 1 to 7, characterized in that, The submicron surface-modified angular silica powder D 50 Particle size is 0.4~0.8μm, D 100 Particle size < 5 μm, specific surface area 6~10 m² 2 / g.

9. The submicron surface-modified angular silica powder according to claim 8, characterized in that, The submicron surface-modified angular silica powder has a SiO2 content > 99.0 wt%, a carbon content of 0.4~1.0 wt%, and an oil absorption value of 50~60 g / 100 g.

10. The application of the submicron surface-modified angular silicon powder according to claim 8 or 9 in copper-clad laminates.

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