Silicon dioxide powder for high-speed copper-clad plate and preparation method of silicon dioxide powder

Abstract

The invention relates to the technical field of high-performance fillers, in particular to silicon dioxide powder for a high-speed copper-clad plate and a preparation method of the silicon dioxide powder. Hydroxyl groups are removed at a high temperature in a sectional manner, then the silane coupling agent reacts with the hydroxyl groups on the surface of silicon oxide, and redundant silane coupling agent and water are removed at a high temperature, so that the low-dielectric-loss silicon dioxide with low hydroxyl content is obtained. According to the invention, the process is simple, the dielectric loss value is obviously reduced, and the requirements of a 5G mobile communication system on higher data transmission rate, lower time delay and better high-speed communication capability are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-performance fillers, in particular to a kind of silica powder for high-speed copper-clad plate and preparation method thereof. BACKGROUND

[0002] The information disclosed in the background of the present application is only intended to increase the understanding of the overall background of the present application and should not necessarily be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.

[0003] With the rapid development of 5G communication, artificial intelligence computing power and Internet of Things technology, the performance requirements of high-frequency high-speed electronic equipment on copper-clad plate are increasingly stringent, and the transmission loss, heat resistance and reliability of copper-clad plate are required to be higher. Under this condition, as the core functional filler of copper-clad plate, the dielectric loss (Df) value of silica material is required to be lower.

[0004] Silica (SiO2) is an important inorganic material, which has low thermal expansion coefficient, good thermal stability and excellent chemical stability, and has been widely used in electronic packaging materials such as underfill adhesive, epoxy plastic and insulating adhesive film. The existing method for reducing dielectric loss mainly reduces hydroxyl and water through surface modification, but there are problems such as improper selection of surface modifier, improper process treatment, large fluctuation of dielectric loss reduction, and unstable quality caused by residual modifier.

[0005] For example, in the prior art, by high-temperature heating and etching treatment of silica powder, combined with silane coupling agent treatment, the problem of high dielectric loss tangent of silica powder in the high frequency region in the prior art is solved, but the surface hydroxyl increases significantly after etching with etching liquid, even if the subsequent silane coupling agent treatment is used, the dielectric loss is still high. Or, by adjusting the particle size and specific surface area of spherical silica powder, combined with wet method and high-temperature drying process, the problems of difficult reduction of dielectric loss tangent and low production efficiency in the prior art are solved, the sufficient reduction of dielectric loss tangent and the improvement of production efficiency are realized, however, there are still problems of small specific surface area, high hydroxyl content, which leads to high dielectric loss. SUMMARY

[0006] Therefore, the present application provides a kind of silica powder for high-speed copper-clad plate and preparation method thereof. The present application removes hydroxyl by high temperature in sections, then silane coupling agent reacts with the surface hydroxyl of silica, and the silane coupling agent and water are removed by high temperature, to obtain low dielectric loss silica with low hydroxyl content, solving the problem of high dielectric loss caused by high surface hydroxyl content of silica in the prior art.

[0007] In order to achieve the above purpose, the present application is realized by the following technical scheme: In a first aspect, the present application provides a method for preparing a silica powder for high-speed copper-clad plate, comprising the following steps: (1) heat treating the silica powder in a high-temperature furnace under a protective atmosphere; the heat treating operation is: heating from room temperature to 110-150°C and maintaining for 2-5 hours, continuing to heat to 400-650°C and maintaining for 3-8 hours, and then continuing to heat to 800-1200°C and maintaining for 5-12 hours; (2) naturally cooling to 250-350°C and maintaining, feeding the silica powder into a stirring device, stirring, and feeding a modifying agent into the high-temperature furnace and feeding the gaseous modifying agent from the protective atmosphere into the stirring device; (3) stopping adding the modifying agent, maintaining the high-temperature gas for a certain period of time, and obtaining a low-hydroxyl-content low-dielectric-loss silica powder.

[0008] Further, in step (1), the average particle size of the silica powder is 0.1-10 μm.

[0009] Further, in step (1), the protective atmosphere is one or more of nitrogen, a rare gas or dry air.

[0010] The silica powder is subjected to high-temperature calcination in stages to remove free water, associated hydroxyl groups and isolated hydroxyl groups in sequence, and under the protection of nitrogen, a rare gas or dry air, the volatilized water can be prevented from being polarized and adsorbed on the surface of the silica at high temperature to form new hydroxyl groups.

[0011] Further, in step (2), the stirring frequency is 10-30 Hz.

[0012] Further, in step (2), the mass ratio of the silica powder to the modifying agent is 100:10-1.

[0013] Further, in step (2), the modifying agent is a silane coupling agent or a silazane modifying agent.

[0014] The silane coupling agent is one or more of a silane coupling agent containing an alkenyl group, a fluorine-substituted alkyl group, an amino group or an epoxy group. The silazane modifying agent is one or more of hexamethyldisilazane, tetramethyldisilazane or an alkenyl-unsaturated silazane modifying agent.

[0015] The silane coupling agent containing an alkenyl group includes vinyltrimethoxysilane, vinyltriethoxysilane or vinyl dimethyl ethoxysilane. The silane coupling agent containing a fluorine-substituted alkyl group includes perfluorooctyltriethoxysilane, trifluoropropyltrimethoxysilane or perfluorodecyltriethoxysilane. The silane coupling agent containing amino group includes γ-aminopropyl triethoxysilane, γ-aminopropyl trimethoxysilane or N-β-aminoethyl-γ-aminopropyl trimethoxysilane; The silane coupling agent containing epoxy group includes γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl triethoxysilane or β-(3,4-epoxycyclohexyl) ethyl trimethoxysilane; The silazane modifier containing alkenyl unsaturated silazane includes tetramethyldivinyl disilazane, methylvinylsilazane, vinylsilazane.

[0016] Further, the modifier is vinyl trimethoxysilane coupling agent, hexamethyldisilazane or perfluorooctyl triethoxysilane.

[0017] Further, in step (2), the protective gas flow is one or more of nitrogen, noble gas or dry air.

[0018] The modifier is rapidly gasified into a gaseous state by the temperature of the high-temperature furnace, and is transported into the stirring device under the protective gas flow, and the modifier can efficiently react with the hydroxyl group of the silicon dioxide under the action of the gaseous state.

[0019] Further, in step (3), the high-temperature gas is maintained for 3-5 h and then turned off.

[0020] Further, in step (3), the high-temperature gas is one or more of nitrogen, noble gas or dry air. After the addition of the modifier is stopped, the small-molecule modifier remaining in the silicon dioxide powder can be removed by using the high-temperature gas flow.

[0021] In a second aspect, the present application provides a silicon dioxide powder prepared by the method of the first aspect.

[0022] Further, the Df of the silicon dioxide powder is ≤0.015, and the relative value of the infrared hydroxyl group is ≤320.

[0023] Compared with the prior art, the present application has the following beneficial effects: (1) The silicon dioxide powder is calcined at high temperature in sections, and the free water, associated hydroxyl group and isolated hydroxyl group are removed in turn. Under the protection of nitrogen, noble gas or dry air, the volatilized water can be prevented from being polarized and adsorbed on the surface of the silicon dioxide at high temperature to form new hydroxyl groups. The modifier is rapidly gasified into a gaseous state by the temperature of the high-temperature furnace, and is transported into the stirring device under the protective gas flow, and the modifier can efficiently react with the hydroxyl group of the silicon dioxide under the action of the gaseous state. After the addition of the modifier is stopped, the small-molecule modifier remaining in the silicon dioxide powder can be removed by using the high-temperature gas flow.

[0024] (2) The process is simple, significantly reduces the dielectric loss value, and meets the requirements of the 5G mobile communication system for higher data transmission rate, lower latency and better high-speed communication capability. DETAILED DESCRIPTION

[0025] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0026] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0027] The technical solutions of the present application will be further described below in conjunction with specific embodiments.

[0028] Example 1 Silicon dioxide powder with an average particle size of 0.1 pm was put into a high-temperature furnace and nitrogen was introduced. The temperature was raised from room temperature to 150 DEG C and maintained for 5 h, then raised to 650 DEG C and maintained for 8 h, then raised to 1200 DEG C and maintained for 12 h.

[0029] The temperature was naturally lowered to 250 DEG C and maintained, the silicon dioxide powder was transported into the stirred tank and stirred at a frequency of 30 Hz, and vinyltrimethoxysilane coupling agent was introduced into the high-temperature furnace, the mass ratio of silicon dioxide powder to vinyltrimethoxysilane coupling agent was 100:10, after vaporization, nitrogen was used to transport it to the stirred tank.

[0030] The addition of vinyltrimethoxysilane coupling agent was stopped, the equipment was closed after maintaining high-temperature nitrogen for 5 h, and low-hydroxyl content low-dielectric loss silicon dioxide powder was obtained.

[0031] Example 2 Silicon dioxide powder with an average particle size of 5 pm was put into a high-temperature furnace and helium was introduced. The temperature was raised from room temperature to 130 DEG C and maintained for 3 h, then raised to 500 DEG C and maintained for 5 h, then raised to 1000 DEG C and maintained for 8 h.

[0032] The temperature was naturally lowered to 300 DEG C and maintained, the silicon dioxide powder was transported into the stirred tank and stirred at a frequency of 20 Hz, and hexamethyldisilazane was introduced into the high-temperature furnace, the mass ratio of silicon dioxide powder to hexamethyldisilazane was 100:5, after vaporization, helium was used to transport it to the stirred tank.

[0033] The addition of hexamethyldisilazane was stopped, the equipment was closed after maintaining high-temperature dry air for 4 h, and low-hydroxyl content low-dielectric loss silicon dioxide powder was obtained.

[0034] Example 3 Silica powder with an average particle size of 10 μm was put into a high-temperature furnace, and helium gas was introduced. The temperature was raised from room temperature to 110°C and maintained for 2 h, then raised to 400°C and maintained for 3 h, and then raised to 800°C and maintained for 5 h.

[0035] The temperature was naturally lowered to 250°C and maintained, and the silica powder was transported into a stirred tank, stirred at a frequency of 10 Hz, and perfluorooctyltriethoxysilane was introduced into the high-temperature furnace. The mass ratio of the silica powder to the perfluorooctyltriethoxysilane was 100:1, and after vaporization, helium gas was used to transport it into the stirred tank.

[0036] The addition of the perfluorooctyltriethoxysilane was stopped, the high-temperature helium gas was maintained for 3 h, and then the equipment was shut down, obtaining low-hydroxyl-content, low-dielectric-loss silica powder.

[0037] Comparative Example 1 Silica powder with an average particle size of 0.1 μm was put into a high-temperature furnace, and no protective gas was introduced. The temperature was raised from room temperature to 150°C and maintained for 5 h, then raised to 650°C and maintained for 8 h, and then raised to 1200°C and maintained for 12 h.

[0038] The temperature was naturally lowered to 250°C and maintained, and the silica powder was transported into a stirred tank, stirred at a frequency of 30 Hz, and a vinyltrimethoxysilane coupling agent was introduced into the high-temperature furnace. The mass ratio of the silica powder to the vinyltrimethoxysilane coupling agent was 100:10, and after vaporization, nitrogen gas was used to transport it into the stirred tank.

[0039] The addition of the vinyltrimethoxysilane coupling agent was stopped, high-temperature nitrogen gas was introduced for 5 h, and then the equipment was shut down, obtaining silica powder.

[0040] Comparative Example 2 Silica powder with an average particle size of 0.1 μm was put into a high-temperature furnace, and protective nitrogen gas was introduced. The temperature was raised from room temperature to 1200°C and maintained for 12 h.

[0041] The temperature was naturally lowered to 250°C and maintained, and the silica powder was transported into a stirred tank, stirred at a frequency of 30 Hz, and a vinyltrimethoxysilane coupling agent was introduced into the high-temperature furnace. The mass ratio of the silica powder to the vinyltrimethoxysilane coupling agent was 100:10, and after vaporization, nitrogen gas was used to transport it into the stirred tank.

[0042] The addition of the vinyltrimethoxysilane coupling agent was stopped, high-temperature nitrogen gas was introduced for 5 h, and then the equipment was shut down, obtaining silica powder.

[0043] Comparative Example 3 Silica powder with an average particle size of 0.1 μm was put into a high-temperature furnace, and nitrogen was introduced. The temperature was raised from room temperature to 150°C and maintained for 5 h, then raised to 650°C and maintained for 8 h, and then raised to 1200°C and maintained for 12 h.

[0044] The temperature was naturally lowered to 250°C and maintained, the silica powder was transported into a stirred tank, stirred at a frequency of 30 Hz, hexadecyltrimethoxysilane was introduced into the high-temperature furnace, and the mass ratio of silica powder to hexadecyltrimethoxysilane was 100:10. After vaporization, nitrogen was used to transport it into the stirred tank.

[0045] The addition of hexadecyltrimethoxysilane was stopped, the high-temperature nitrogen was maintained for 5 h, and then the equipment was shut down to obtain low-hydroxyl-content low-dielectric-loss silica powder.

[0046] Comparative Example 4 Silica powder with an average particle size of 0.1 μm was put into a high-temperature furnace, and nitrogen was introduced. The temperature was raised from room temperature to 650°C and maintained for 8 h, and then raised to 1200°C and maintained for 12 h.

[0047] The temperature was naturally lowered to 250°C and maintained, the silica powder was transported into a stirred tank, stirred at a frequency of 30 Hz, vinyltrimethoxysilane coupling agent was introduced into the high-temperature furnace, and the mass ratio of silica powder to vinyltrimethoxysilane coupling agent was 100:10. After vaporization, nitrogen was used to transport it into the stirred tank.

[0048] The addition of vinyltrimethoxysilane coupling agent was stopped, the high-temperature nitrogen was maintained for 5 h, and then the equipment was shut down to obtain silica powder.

[0049] Comparative Example 5 Silica powder with an average particle size of 0.1 μm was put into a high-temperature furnace, and nitrogen was introduced. The temperature was raised from room temperature to 150°C and maintained for 5 h, and then raised to 1200°C and maintained for 12 h.

[0050] The temperature was naturally lowered to 250°C and maintained, the silica powder was transported into a stirred tank, stirred at a frequency of 30 Hz, vinyltrimethoxysilane coupling agent was introduced into the high-temperature furnace, and the mass ratio of silica powder to vinyltrimethoxysilane coupling agent was 100:10. After vaporization, nitrogen was used to transport it into the stirred tank.

[0051] The addition of vinyltrimethoxysilane coupling agent was stopped, the high-temperature nitrogen was maintained for 5 h, and then the equipment was shut down to obtain silica powder.

[0052] Test Method 1. Infrared Hydroxyl Relative Value Test Method: Fourier Transform Infrared Spectrophotometer, Diffuse Reflection Measurement Device, Diffuse Reflection Method, Infrared Wavenumber 3760-3730 cm-1 the sum of the isolated hydroxyl area at 3730-3520 cm -1 and the associated hydroxyl area at 3650-3560 cm

[0053] 2. The dielectric loss Df test method: the sample to be tested, vinyl silicone oil, curing agent, catalyst are stirred uniformly according to the proportion and the bubbles are removed to obtain a composition, the composition is added to an 8cm x 4cm x 0.2cm mold, placed in 2 glass plates and manually flattened and cured at 150℃ for 30min. The dielectric loss Df at 10GHz is measured using a separate dielectric resonator frequency of 10GHz (P5004B manufactured by Keysight Technologies Corporation).

[0054] The test results of examples 1-3 and comparative examples 1-5 are shown in Table 1.

[0055] Table 1 Test results of examples 1-3 and comparative examples 1-5

[0056] As can be seen from Table 1, the relative value of infrared hydroxyl group of the silica powder prepared in examples 1-3 is ≤320, and Df is ≤0.015. In examples 1-3, the average particle size is 0.1μm, 5.2μm and 10μm respectively, and under the condition of sub-particle size, low hydroxyl content and low dielectric loss silica powder can be prepared. In comparative example 1, no protective gas is introduced during the high temperature treatment stage, the relative value of infrared hydroxyl group is 350, and Df is 0.0156, therefore, the introduction of protective gas during the high temperature treatment stage can prevent the volatilized water from being polarized and adsorbed on the surface of silica at high temperature to form new hydroxyl groups. In comparative example 2, there is no first and second stage temperature rising and holding process during heat treatment, in comparative example 4, there is no first stage temperature rising and holding process, and in comparative example 5, there is no second stage temperature rising and holding process. From the results, the relative value of infrared hydroxyl group of comparative examples 2, 4 and 5 is all above 350, and Df is all above 0.016. This also verifies that the segmented high temperature calcination of the present application has a greater effect on the removal of hydroxyl group and Df. In comparative example 3, hexadecyl trimethoxysilane is used as a modifier, which results in the relative value of infrared hydroxyl group and Df value being higher than examples 1-3.

[0057] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a silica powder for high-speed copper clad plates, characterized by, The method comprises the following steps: (1) under a protective atmosphere, heat treating the silica powder in a high temperature furnace; the heat treating operation is: raising the temperature from room temperature to 110-150℃ and maintaining for 2-5h, continuously raising the temperature to 400-650℃ and maintaining for 3-8h, continuously raising the temperature to 800-1200℃ and maintaining for 5-12h; (2) naturally lowering the temperature to 250-350℃ and maintaining, feeding the silica powder into a stirring device, stirring, and feeding the modified agent into the high temperature furnace and feeding the gasified modified agent from the protective gas flow into the stirring device; (3) stopping adding the modified agent, maintaining the high temperature gas for a certain time, and obtaining the low hydroxyl content and low dielectric loss silica powder.

2. The production method according to claim 1, wherein In step (2), the stirring frequency is 10-30Hz.

3. The production method according to claim 1, wherein The mass ratio of the silica powder to the modified agent is 100:10-1.

4. The production method according to claim 1, wherein In step (2), the modified agent is a silane coupling agent or a silazane modified agent; Preferably, the silane coupling agent is one or several of silane coupling agents containing alkenyl, fluorine-substituted alkyl, amino, and epoxy groups; Preferably, the silazane modified agent is one or several of hexamethyldisilazane, tetramethyldisilazane, and silazane modified agent containing alkenyl unsaturated silazane.

5. The production method according to claim 4, wherein The modified agent is vinyltrimethoxysilane coupling agent, hexamethyldisilazane, or perfluorooctyltriethoxysilane.

6. The production method according to claim 1, wherein In step (2), the protective gas flow is one or several of nitrogen, rare gas, or dry air.

7. The production method according to claim 1, wherein In step (3), the high temperature gas is maintained for 3-5h.

8. The production method according to claim 1, wherein In step (3), the high temperature gas is one or several of nitrogen, rare gas, or dry air.

9. The silica powder prepared by the preparation method according to any one of claims 1-8.

10. The silica powder according to claim 9, wherein The Df of the silica powder is ≤0.015, and the infrared hydroxyl relative value is ≤320.

Images