阅读说明：本技术 一种球形二氧化硅粉体填料的制备方法、由此得到的粉体填料及其应用 (Preparation method of spherical silicon dioxide powder filler, powder filler obtained by preparation method and application of powder filler ) 是由 陈树真 李锐 王珂 丁烈平 沈海斌 于 2020-04-26 设计创作，主要内容包括：本发明涉及一种球形二氧化硅粉体填料的制备方法,其包括如下步骤：S1,由R<Sub>1</Sub>SiX<Sub>3</Sub>的加水分解缩合反应来提供包括T单位的球形聚硅氧烷,其中,R<Sub>1</Sub>为氢原子或可独立选择的碳原子1至18的有机基,X为加水可分解基团,T单位为R<Sub>1</Sub>SiO<Sub>3</Sub>-；S2,在干燥的氧化气体氛围条件下煅烧球形聚硅氧烷,煅烧温度介于850度-1200度之间,得到低羟基含量的球形二氧化硅粉体填料,该球形二氧化硅粉体填料由选自Q<Sub>1</Sub>单位、Q<Sub>2</Sub>单位、Q<Sub>3</Sub>单位和Q<Sub>4</Sub>单位中的至少一种组成,其中,Q<Sub>1</Sub>单位为Si(OH)<Sub>3</Sub>O-,Q<Sub>2</Sub>单位为Si(OH)<Sub>2</Sub>O<Sub>2</Sub>-,Q<Sub>3</Sub>单位为SiOHO<Sub>3</Sub>-,Q<Sub>4</Sub>单位为SiO<Sub>4</Sub>-,Q<Sub>4</Sub>单位的含量大于等于95％。根据本发明的球形二氧化硅粉体填料低羟基含量,具有低介电损失和低热膨胀系数,适用于高频高速电路板,半固化片或覆铜板等。(The invention relates to a preparation method of a spherical silicon dioxide powder filler, which comprises the following steps: s1, from R 1 SiX 3 To provide a spherical polysiloxane comprising T units, wherein R is 1 Is a hydrogen atom or an independently selected organic group of carbon atoms 1 to 18, X is a water-decomposable group, and T has the unit of R 1 SiO 3 -; s2, calcining the spherical polysiloxane under the dry oxidizing gas atmosphere condition, wherein the calcining temperature is between 850 and 1200 ℃, and obtaining the spherical di-component with low hydroxyl contentSilica powder filler, the spherical silica powder filler is selected from Q 1 Unit, Q 2 Unit, Q 3 Unit and Q 4 At least one of the units, wherein Q 1 Units are Si (OH) 3 O‑，Q 2 Units are Si (OH) 2 O 2 ‑，Q 3 Unit is SiOHO 3 ‑，Q 4 Has the unit of SiO 4 ‑，Q 4 The content of the unit is greater than or equal to 95 percent. The spherical silicon dioxide powder filler has low hydroxyl content, low dielectric loss and low thermal expansion coefficient, and is suitable for high-frequency high-speed circuit boards, prepregs or copper-clad plates and the like.)

1. A preparation method of spherical silica powder filler is characterized by comprising the following steps:

s1, from R₁SiX₃To provide a spherical polysiloxane comprising T units, wherein R is₁Is a hydrogen atom or an independently selected organic group of carbon atoms 1 to 18, X is a water-decomposable group, and T has the unit of R₁SiO₃-；

S2, calcining the spherical polysiloxane under the dry oxidizing gas atmosphere condition, wherein the calcining temperature is between 850 ℃ and 1200 ℃, and the spherical silica powder filler with low hydroxyl content is obtained and is selected from Q₁Unit, Q₂Unit, Q₃Unit and Q₄At least one of the units, wherein Q₁Units are Si (OH)₃O-，Q₂Units are Si (OH)₂O₂-，Q₃Unit is SiOHO₃-，Q₄Has the unit of SiO₄-，Q₄The content of the unit is greater than or equal to 95 percent.

2. The process according to claim 1, wherein the group decomposable by addition of water is an alkoxy group or a halogen atom.

3. The method according to claim 1, wherein the oxidizing gas contains oxygen to oxidize all organic substances in the polysiloxane.

4. The method according to claim 1, wherein the spherical polysiloxane is calcined by electric heating or indirect gas heating.

5. The method of claim 1, wherein the calcination temperature is 850-1100 ℃ and the calcination time is 6-12 hours.

6. The method according to claim 1, wherein the spherical polysiloxane further contains Q units, D units, and/or M units, wherein Q units are SiO units₄-, D unit ═ R₂R₃SiO₂-, M units ═ R₄R₅R₆SiO₂-，R₂，R₃，R₄，R₅，R₆Each hydrogen atom or an independently selected hydrocarbyl group of carbon atoms 1 to 18.

7. The preparation method of claim 1, further comprising adding a treating agent to perform surface treatment on the spherical silica powder filler, wherein the treating agent comprises a silane coupling agent and/or disilazane; the silane coupling agent is (R)₇)_a(R₈)_bSi(M)_4-a-b，R₇，R₈Is an independently selectable hydrocarbon group of carbon atoms 1 to 18, a hydrogen atom, or a hydrocarbon group of carbon atoms 1 to 18 substituted with a functional group selected from at least one of the following organofunctional groups: vinyl, allyl, styryl, epoxy, aliphatic amino, aromatic amino, methacryloxypropyl, acryloxypropyl, ureidopropyl, chloropropyl, mercaptopropyl, polysulfide, isocyanatopropyl; m is a hydrocarbyloxy group of carbon atoms 1 to 18 or a halogen atom, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, a + b is 1, 2 or 3; the disilazane is (R)₉R₁₀R₁₁)SiNHSi(R₁₂R₁₃R₁₄)，R₉，R₁₀，R₁₁，R₁₂，R₁₃，R₁₄Is an independently selected hydrocarbon group of carbon atoms 1 to 18 or a hydrogen atom.

8. The spherical silica powder filler obtained by the preparation method according to any one of claims 1 to 7, wherein the spherical silica powder filler has a low hydroxyl group content, and the average particle diameter of the spherical silica powder filler is between 0.1 and 5 microns.

9. The use of spherical silica powder filler according to claim 8, wherein spherical silica powder fillers of different particle sizes are tightly packed and graded in a resin to form a composite material suitable for circuit board materials and semiconductor packaging materials.

10. Use according to claim 9, characterized in that it comprises removing coarse large particles of 1, 3, 5, 10, 20 microns or more in the spherical silica powder filler using dry or wet sieving or inertial classification.

Technical Field

The invention relates to a circuit board, in particular to a preparation method of a spherical silicon dioxide powder filler, the powder filler obtained by the preparation method and application of the powder filler.

Background

In the field of 5G communication, radio frequency devices and the like are required to be used to assemble equipment, High Density Interconnect (HDI) boards, high frequency high speed boards, mother boards and other circuit boards. These circuit boards are generally composed of an organic polymer such as epoxy resin, aromatic polyether, fluororesin, etc., and a filler, wherein the filler is mainly angular or spherical silica, and has a main function of reducing the thermal expansion coefficient of the organic polymer. The existing filler is selected from spherical or angular silica for tight filling grading.

On the other hand, with the progress of technology, the frequency of signals used in semiconductors is becoming higher, and the high speed and low loss of signal transmission speed require fillers having low dielectric loss and dielectric constant. The dielectric constant of a material depends essentially on the chemical composition and structure of the material, and silicon dioxide has its inherent dielectric constant. On the other hand, the dielectric loss is related to polar groups of the filler such as hydroxyl groups, and the more hydroxyl groups, the greater the dielectric loss. The traditional spherical silicon dioxide is prepared by adopting a high-temperature flame heating mode and utilizing physical melting or chemical oxidation. The flame is formed by burning hydrocarbon fuel such as LPG, NG and the like and oxygen, and a large amount of water molecules are generated in the flame. Therefore, the obtained silicon oxide powder has a large amount of polar hydroxyl groups in the interior and on the surface, which increases the dielectric loss, and is not suitable for the dielectric performance requirements of the high-frequency high-speed circuit board in the 5G communication era. Another disadvantage of the flame method is that the temperature is typically higher than the boiling point of silica, 2230 degrees, which results in condensation of the vaporized silica to produce silica below tens of nanometers (e.g., 50 nanometers). There is a specific surface area-constant inverse function relationship of particle diameter between the specific surface area and the diameter of the spherical silica, i.e. a decrease in diameter leads to a sharp increase in specific surface area. The calculated specific surface area of the spherical silica, e.g. having a diameter of 0.5 μm, is 5.6m²Calculated specific surface area of 50 nm spherical silica is 54.5m²(ii) in terms of/g. The increase in specific surface area leads to an increase in the amount of adsorbed water. Water molecules are understood to contain two hydroxyl groups, which leads to a drastic deterioration of the dielectric loss of the silicon oxide powder.

Disclosure of Invention

In order to solve the problem of silica particles with higher hydroxyl content in the silica powder filler in the prior art, the invention provides a preparation method of a spherical silica powder filler, the powder filler obtained by the preparation method and application of the powder filler.

The invention provides a preparation method of a spherical silicon dioxide powder filler, which comprises the following steps: s1, from R₁SiX₃To provide a spherical polysiloxane comprising T units, wherein R is₁An organic radical being a hydrogen atom or an independently selected carbon atom from 1 to 18X is a group decomposable by adding water and T has the unit of R₁SiO₃-; s2, calcining the spherical polysiloxane under the dry oxidizing gas atmosphere condition, wherein the calcining temperature is between 850 ℃ and 1200 ℃, and the spherical silica powder filler with low hydroxyl content is obtained and is selected from Q₁Unit, Q₂Unit, Q₃Unit and Q₄At least one of the units, wherein Q₁Units are Si (OH)₃O-，Q₂Units are Si (OH)₂O₂-，Q₃Unit is SiOHO₃-，Q₄Has the unit of SiO₄-，Q₄The content of the unit is greater than or equal to 95 percent.

Preferably, the water-decomposable group X is an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group or the like, or a halogen atom such as a chlorine atom or the like. The catalyst for the hydrolysis condensation reaction may be a base and/or an acid.

Preferably, the oxidizing gas contains oxygen to oxidize all organic matter in the polysiloxane. From a cost perspective, the oxidizing gas is preferably air. In order to reduce the hydroxyl group content of the silica after calcination, the smaller the moisture content in the air, the better. From the viewpoint of cost, it is suitable for the atmosphere of calcination of the present invention to remove moisture by a freeze dryer after compressing air. Specifically, the step S2 includes: and putting the spherical polysiloxane powder into a muffle furnace, and introducing dry air for calcining.

Preferably, the calcination of the spherical polysiloxane is achieved by electrical heating or gas indirect heating. It should be understood that the heating method of the present invention is not particularly limited, but the present invention preferably avoids direct heating by gas flame as much as possible because the combustion gas of gas contains moisture. The temperature can be gradually increased during calcination, and the slow heating at the temperature lower than 850 ℃ and room temperature is beneficial to the slow decomposition of organic groups, so that the residual carbon in the finally calcined silicon dioxide is reduced. The whiteness of silica decreases with high residual carbon.

Preferably, the calcination temperature is between 850 degrees and 1100 degrees and the calcination time is between 6 hours and 12 hours.

Preferably, the spherical siliconeThe alkane further contains Q units, D units, and/or M units, wherein Q units are SiO₄-, D unit ═ R₂R₃SiO₂-, M units ═ R₄R₅R₆SiO₂-，R₂，R₃，R₄，R₅，R₆Each hydrogen atom or an independently selected hydrocarbyl group of carbon atoms 1 to 18. For example, in a preferred embodiment, Si (OC)₂C₃)₄,CH₃CH₃Si(OCH₃)₂Can be mixed with CH₃Si(OCH₃)₃Mixing and using.

Preferably, the preparation method further comprises the step of adding a treating agent to carry out surface treatment on the spherical silica powder filler, wherein the treating agent comprises a silane coupling agent and/or disilazane; the silane coupling agent is (R)₇)_a(R₈)_bSi(M)_4-a-b，R₇，R₈Is an independently selectable hydrocarbon group of carbon atoms 1 to 18, a hydrogen atom, or a hydrocarbon group of carbon atoms 1 to 18 substituted with a functional group selected from at least one of the following organofunctional groups: vinyl, allyl, styryl, epoxy, aliphatic amino, aromatic amino, methacryloxypropyl, acryloxypropyl, ureidopropyl, chloropropyl, mercaptopropyl, polysulfide, isocyanatopropyl; m is a hydrocarbyloxy group of carbon atoms 1 to 18 or a halogen atom, a is 0, 1, 2 or 3, b is 0, 1, 2 or 3, a + b is 1, 2 or 3; the disilazane is (R)₉R₁₀R₁₁)SiNHSi(R₁₂R₁₃R₁₄)，R₉，R₁₀，R₁₁，R₁₂，R₁₃，R₁₄Is an independently selected hydrocarbon group of carbon atoms 1 to 18 or a hydrogen atom.

The invention also provides the spherical silica powder filler obtained by the preparation method, the hydroxyl content of the spherical silica powder filler is low, and the average particle size of the spherical silica powder filler is between 0.1 and 5 microns. More preferably, the spherical silica powder filler has an average particle size of between 0.15 microns and 4.5 microns.

The invention also provides the application of the spherical silica powder filler, and the spherical silica powder filler with different grain diameters is tightly filled and graded in resin to form a composite material which is suitable for circuit board materials and semiconductor packaging materials. Preferably, the spherical silica powder filler is suitable for high-frequency high-speed circuit board materials, prepregs, copper-clad plates and other semiconductor packaging materials requiring low dielectric loss.

Preferably, the application comprises removing coarse large particles of 1 micron, 3 microns, 5 microns, 10 microns, 20 microns or more in the spherical silica powder filler using dry or wet sieving or inertial classification.

The spherical silicon dioxide powder filler has low hydroxyl content, low dielectric loss and low thermal expansion coefficient, and is suitable for high-frequency high-speed circuit boards, prepregs or copper-clad plates and the like.

Detailed Description

The following provides a detailed description of the preferred embodiments of the present invention.

The detection methods referred to in the following examples include:

the average particle size is measured by a laser particle size distribution instrument LA-700 of HORIBA;

q of spherical silica powder filler₁Unit, Q₂Unit, Q₃Unit and Q₄Utilization of unit content²⁹Si solid NMR Nuclear magnetic resonance Spectroscopy according to Q₁Unit, Q₂Unit, Q₃Unit and Q₄The nuclear magnetic resonance absorption peak area of the unit was calculated. Q₄Unit content (%) ═ Q₄Unit peak area/(Q)₁Unit peak area + Q₂Unit peak area + Q₃Unit peak area + Q₄Unit peak area)) × 100;

the dielectric loss test method is to mix sample powder with different volume fractions and paraffin to prepare test samples, and measure the dielectric loss by a high-frequency dielectric loss instrument from vendors under the condition of 10 GHz. The dielectric loss was plotted on the ordinate and the volume fraction of the sample on the abscissa, and the dielectric loss of the sample was determined from the slope. Although the absolute value of the dielectric loss is generally difficult to obtain, the dielectric losses of the examples and comparative examples of the present application can be at least relatively compared.

Herein, "degree" refers to "degrees celsius", i.e. celsius.

Herein, the average particle diameter refers to the volume average diameter of the particles.

Example 1

At room temperature, a certain weight part of deionized water is put into a reaction kettle with a stirrer, the stirring is started, and 80 weight parts of methyltrimethoxysilane and a small amount of acetic acid are added to adjust the pH to about 5. After the methyltrimethoxysilane was dissolved, 25 parts by weight of 5% ammonia water was added thereto, and the mixture was stirred for 10 seconds, and then the stirring was stopped. Standing for 1 hour, filtering, and drying to obtain the spherical polysiloxane. And (3) putting the polysiloxane powder into a muffle furnace, and introducing dry air to calcine the polysiloxane powder, wherein the final calcining temperature is 850 ℃, 1000 ℃ or 1100 ℃ and the calcining time is 12 hours. The results of the analysis of the samples are shown in Table 1 below.

TABLE 1

Example 2

At room temperature, 1100 parts by weight of deionized water is put into a reaction kettle with a stirrer, and 80 parts by weight of propyl trimethoxy silane and a small amount of acetic acid are added with stirring to adjust the pH to about 5. After the propyltrimethoxysilane was dissolved, 25 parts by weight of 5% ammonia water was added thereto and stirred for 10 seconds, and then the stirring was stopped. Standing for 1 hour, filtering, and drying to obtain the spherical polysiloxane. And (3) putting the polysiloxane powder into a muffle furnace, and introducing dry air to calcine the polysiloxane powder, wherein the final calcining temperature is 950 ℃ and the calcining time is 6 hours. The results of the analysis of the samples are shown in Table 2 below.

TABLE 2

Example 3

Placing 2500 parts by weight of 40 ℃ deionized water into a reaction kettle with a stirrer, starting stirring, adding 80 parts by weight of methyltrimethoxysilane and a small amount of acetic acid, and adjusting the pH to about 5. After the methyltrimethoxysilane was dissolved, 60 parts by weight of 5% ammonia water was added thereto, and the mixture was stirred for 10 seconds, and then the stirring was stopped. Standing for 1 hour, filtering, and drying to obtain the spherical polysiloxane. And (3) putting the polysiloxane powder into a muffle furnace, and introducing dry air to calcine the polysiloxane powder, wherein the final calcining temperature is 1000 ℃, and the calcining time is 12 hours. The heating mode was changed to natural gas combustion (comparative example 2), the combustion gas was directly heated, the final calcination temperature was 1000 ℃ and the calcination time was 12 hours. The results of the analysis of the samples are shown in Table 3 below. It is clear that the presence of moisture in the hot gases after combustion of natural gas leads to an increase in the hydroxyl groups in the silica.

TABLE 3

Example 4

Crushed silica having an average particle diameter of 2 μm was fed into a spheroidizing furnace having a flame temperature of 2500 ℃ to be melt-spheroidized. The spheroidized powder was collected as a sample of comparative example 3. The results of the analysis of the samples are shown in Table 4 below.

TABLE 4

It is to be understood that the example samples obtained in examples 1 to 6 described above may be surface-treated. Specifically, treatments such as a vinyl silane coupling agent, epoxy silane coupling, disilazane, and the like may be performed as necessary. More than one treatment may be performed as necessary.

It is to be understood that the preparation method includes the use of dry or wet screening or inertial classification to remove coarse large particles above 1, 3, 5, 10, 20 microns in the filler.

It should be understood that the closely packed grading of spherical silica fillers of different particle sizes forms a composite in the resin.

The above embodiments are merely preferred embodiments of the present invention, which are not intended to limit the scope of the present invention, and various changes may be made in the above embodiments of the present invention. All simple and equivalent changes and modifications made according to the claims and the content of the specification of the present application fall within the scope of the claims of the present patent application. The invention has not been described in detail in order to avoid obscuring the invention.