Organic silicon micro powder and preparation method and application thereof

Abstract

The invention relates to the technical field of optical materials, and discloses organic silicon micropowder as well as a preparation method and application thereof. The organic silicon micro powder is composed of a plurality of polysiloxane microspheres, the surface relative smoothness of each polysiloxane microsphere is R, 1.02 < = R < = 1.30, R = Rq / Ra, Rq is the root mean square surface roughness of the polysiloxane microspheres, and Ra is the average surface roughness of the polysiloxane microspheres; the relative size uniformity of the organic silicon micro-powder is RSU, RSU = 1-phi / d2 > = 0.992, phi is the variance of the diameter of the organic silicon micro-powder, and d is the average diameter of the organic silicon micro-powder. The organic silicon micropowder has the advantages of higher light utilization rate, higher light transmittance and good light scattering and diffusion uniformity; after the material is applied to a light diffusion material, the light control fineness is high, the light transmittance and diffusivity are good, and the light transmittance and brightness are higher; and the flatness of the coating formed when the coating is used as a raw material for forming the coating is good.

Description

Technical Field

[0001] The present invention relates to the technical field of optical materials, and in particular to organosilicon micropowder, a preparation method and application thereof. Background Art

[0002] Point light sources, the primary form of LED light sources, are prone to glare and spotlighting. Direct use in indoor lighting can cause eye damage. LED lighting housing materials, also known as light-scattering materials, are materials that both transmit light and effectively scatter it, transforming point and linear light sources into linear and surface light sources. The two key performance indicators for evaluating light-scattering materials are transmittance and haze. To achieve a soft, even light effect, light-scattering materials are generally required to have a transmittance of over 80% and a haze of over 90%. To cope with the rapid growth of the LED lighting industry, the production of housing materials must be continuous and high-yield. Therefore, most new light-scattering materials are prepared by blending a transparent polymer matrix with a light-diffusing agent. Commonly used light-scattering matrix materials are transparent polymers, such as polycarbonate (PC), polystyrene (PS), transparent polyolefins, polyethylene terephthalate (PET), and polymethyl methacrylate (PMMA).

[0003] Currently, the most commonly used light diffusers are inorganic or organosilicon micropowders. Inorganic microspheres, when used as light diffusers, often significantly reduce light transmittance, thereby increasing haze and affecting optical performance. During back-end applications, inorganic microspheres exhibit poor compatibility when mixed with the polymer matrix, leading to agglomeration and negatively impacting the material's mechanical properties. Furthermore, inorganic microspheres are also highly hard, causing wear and tear on processing equipment. Consequently, inorganic microspheres have significant drawbacks as light diffusers.

[0004] Silicone light diffusers are a material that has garnered widespread attention in recent years, particularly for their potential applications in the optical field. Silicone light diffusers can alter the path of light, improving its transmission and scattering properties, thereby increasing light utilization and uniformity. However, current silicone diffusers, when used in light-scattering materials, struggle to simultaneously achieve high transmittance and haze requirements.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide organosilicon micropowder and its preparation method and application, aiming to improve at least one problem mentioned in the background technology.

[0007] The present invention is achieved in that: In a first aspect, the present invention provides an organosilicon micropowder, which is composed of a plurality of polysiloxane microspheres, wherein the relative surface smoothness of each polysiloxane microsphere is R, 1.02≤R≤1.30, wherein R=Rq / Ra, Rq is the root mean square surface roughness of the polysiloxane microsphere, and Ra is the average surface roughness of the polysiloxane microsphere; The relative size uniformity of silicone powder is RSU, RSU=1-φ / d 2 ≥0.992, where φ is the variance of the organosilicon powder diameter and d is the average diameter of the organosilicon powder.

[0008] In an optional embodiment, each polysiloxane microsphere has a root mean square surface roughness Rq≤120 nm and an average surface roughness Ra≤100 nm.

[0009] In an optional embodiment, the root mean square surface roughness of each polysiloxane microsphere is 48 nm ≤ Rq ≤ 101.1 nm, and the average surface roughness is 38 nm ≤ Ra ≤ 97.2 nm.

[0010] In an optional embodiment, at least one of the following features (1) and (2) is included: (1) The average diameter d of the organosilicon powder is 0.5~10μm; (2) The maximum diameter of the polysiloxane microspheres in the silicone micropowder is d max , the minimum diameter is d min ,(d max -d min ) / d×100%≤20%.

[0011] In a second aspect, the present invention provides a method for preparing organosilicon micropowder, comprising: Providing a hydrolyzate, wherein the hydrolyzate is obtained by reacting siloxane and water in a mass ratio of 1:3 to 20, and the conductivity of the hydrolyzate is 3 to 20 μS / cm; Providing a mixed solution, mixing the hydrolyzed solution and the base at ≤0°C to obtain a mixed solution having a pH of 9 to 11.5; The temperature of the mixed solution is raised to a polycondensation temperature of 40 to 60°C. During the temperature raising process, the time taken for the mixed solution to reach the polycondensation temperature from 0°C is controlled to be ≤ 60s, so that the substances in the mixed solution undergo a polycondensation reaction. After the reaction is completed, a solid-liquid mixture containing polysiloxane microspheres is obtained. The polysiloxane microspheres are extracted from the solid-liquid mixture to obtain organosilicon micropowder.

[0012] In an optional embodiment, at least one of the following features (1) to (7) is also included: (1) Siloxane is at least one selected from methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane and vinyltrimethoxysilane; (2) The hydrolyzate is mixed with alkali at -5 to 0°C; (3) The heating rate of the mixed solution to the polycondensation temperature is 60~100℃ / min; (4) the base is selected from at least one of sodium hydroxide and potassium hydroxide; (5) The reaction temperature of siloxane and water is 20~30℃, and the reaction time is 0.5~3h; (6) The alkali is mixed with the hydrolyzate in the form of an alkali solution, and the mixing method is: the alkali solution is divided into multiple batches and mixed with the hydrolyzate in batches; (7) The method of extracting polysiloxane microspheres from the solid-liquid mixture includes: performing solid-liquid separation on the solid-liquid mixture, and washing and drying the obtained solid.

[0013] In an optional embodiment, the conductivity of the hydrolyzed solution is 4-15 μS / cm.

[0014] In a third aspect, the present invention provides a light scattering material, comprising the organosilicon micropowder according to any one of the aforementioned embodiments or the organosilicon micropowder prepared by the preparation method according to any one of the aforementioned embodiments.

[0015] In a fourth aspect, the present invention provides a silicon dioxide powder obtained by calcining organic silicon micropowder; The organosilicon micropowder is the organosilicon micropowder according to any one of the aforementioned embodiments or the organosilicon micropowder prepared by the preparation method according to any one of the aforementioned embodiments.

[0016] In a fifth aspect, the present invention provides a copper clad laminate, the components of which include the silicon dioxide powder as described in the aforementioned embodiment.

[0017] The present invention has the following beneficial effects: The organosilicon micropowder provided by the present invention has a relative surface smoothness R of 1.02 ≤ R ≤ 1.30. Within this range, the microspheres are guaranteed to have a smoother surface. This smooth organosilicon micropowder can reduce irregular reflection and scattering of light on the particle surface, thereby improving light utilization efficiency and light transmittance. Microspheres with high surface smoothness exhibit high sphericity, meaning the particles are more uniform in size in all directions, facilitating uniform scattering and diffusion of light, and avoiding the formation of noticeable light spots or dark areas. The more high-sphericity microspheres there are in the powder, the more times the light is deflected on the surface of the sphere, and the more regular the reflection angle is. The light diffusion material prepared with it has higher haze, better use effect, and reduced addition amount; the relative size uniformity RSU of silicone micropowder is ≥0.992. Its high uniformity means that its particle size distribution is narrow, the light transmission control is high, and the transmittance and diffusion are good; the narrower the particle size distribution, the more uniform the scattering of light in the material, which reduces the reflection and refraction of light inside the material, thereby improving the transmittance and brightness of light and achieving finer light transmission control; microspheres with narrow particle size distribution are easier to form a smooth surface during the coating or molding process, reducing surface defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a SEM image of the organosilicon powder prepared in Example 1; Figure 2 This is a SEM image of the organosilicon powder prepared in Example 2; Figure 3 This is a SEM image of the organosilicon powder prepared in Example 8; Figure 4 2D and 3D images of the organosilicon powder prepared in Example 8 are obtained by atomic force microscopy; Figure 5 This is the SEM image of the organosilicon powder prepared in Comparative Example 1; Figure 6 This is the SEM image of the organosilicon powder prepared in Comparative Example 2; Figure 7 This is the SEM image of the organosilicon powder prepared in Comparative Example 4; Figure 8 This is the SEM image of the organosilicon powder prepared in Comparative Example 6. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0021] Explanation of terms involved in this application: Rq (Root Mean Square Roughness): The root mean square value of the profile deviation from the mean line within the sampling length. It is a statistical parameter of surface roughness that reflects the fluctuation of surface height.

[0022] Ra (Arithmetic Mean Deviation of Profile): The arithmetic mean of the absolute values ​​of the distances from each point on the measured profile to the reference line within the sampling length. It is a commonly used indicator of surface roughness and reflects the characteristics of the surface's microscopic geometry.

[0023] When the values ​​of Rq and Ra are closer, the surface height fluctuation is smaller, that is, the surface roughness is lower. This is because Rq and Ra are both parameters used to describe surface roughness, but they measure the surface unevenness from different perspectives: Rq reflects the root mean square value of the surface height, while Ra reflects the arithmetic mean of the surface height; if the two values ​​are close, it means that the surface height fluctuation is within a small range and the surface is relatively smooth.

[0024] Relative size uniformity RSU of silicone micropowder, RSU=1-φ / d 2 , where φ is the variance of the organosilicon powder diameter and d is the average diameter of the organosilicon powder.

[0025] A larger RSU value indicates a narrower particle size distribution, which in turn indicates greater particle size consistency. It should be noted that variance is a technical term in applied mathematics. In this application, the variance of organosilicon micropowder is the average of the squares of the differences between individual diameters and the average diameter of the microspheres.

[0026] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0027] An embodiment of the present invention provides an organosilicon micropowder, which is composed of a plurality of polysiloxane microspheres, wherein the relative smoothness of the surface of each polysiloxane microsphere is R, 1.02≤R≤1.30, wherein R=Rq / Ra, Rq is the root mean square surface roughness of the polysiloxane microsphere, and Ra is the average surface roughness of the polysiloxane microsphere; The relative size uniformity of the organosilicon micropowder is RSU, RSU=1-φ / d2≥0.992, where φ is the variance of the organosilicon micropowder diameter and d is the average diameter of the organosilicon micropowder.

[0028] The organosilicon micropowder provided by the present invention has a relative surface smoothness R of 1.02 ≤ R ≤ 1.30. Within this range, the microspheres are guaranteed to have a smoother surface. This smooth organosilicon micropowder can reduce irregular reflection and scattering of light on the particle surface, thereby improving light utilization efficiency and light transmittance. Microspheres with high surface smoothness exhibit high sphericity, meaning the particles are more uniform in size in all directions, facilitating uniform scattering and diffusion of light, and avoiding the formation of noticeable light spots or dark areas. The more high-sphericity microspheres there are in the powder, the more times the light is deflected on the surface of the sphere, and the more regular the reflection angle is. The light diffusion material prepared with it has higher haze, better use effect, and reduced addition amount; the relative size uniformity RSU of silicone micropowder is ≥0.992. Its high uniformity means that its particle size distribution is narrow, the light transmission control is high, and the transmittance and diffusion are good; the narrower the particle size distribution, the more uniform the scattering of light in the material, which reduces the reflection and refraction of light inside the material, thereby improving the transmittance and brightness of light and achieving finer light transmission control; microspheres with narrow particle size distribution are easier to form a smooth surface during the coating or molding process, reducing surface defects.

[0029] Therefore, the organosilicon micropowder provided by the present invention can ensure that its relative smoothness and relative size uniformity are within the range required by the present invention, thereby ensuring that the organosilicon micropowder has high light utilization rate, high light transmittance, and good uniformity of light scattering and diffusion; after being applied to light diffusion materials, the light control precision is high, the light transmittance and diffusion are good, and the light transmittance and brightness are higher; and when used as a raw material for forming a coating, the coating formed has good flatness.

[0030] Optionally, to further improve the optical properties of the organosilicon micropowder, each polysiloxane microsphere has a root mean square surface roughness Rq ≤ 120 nm and an average surface roughness Ra ≤ 100 nm.

[0031] Optionally, to further improve the optical properties of the organosilicon micropowder, the root mean square surface roughness of each polysiloxane microsphere is 48 nm ≤ Rq ≤ 101.1 nm, and the average surface roughness is 38 nm ≤ Ra ≤ 97.2 nm.

[0032] Optionally, to further improve the optical properties of the organosilicon micropowder, the average diameter d of the organosilicon micropowder is 0.5-10 μm.

[0033] The existing view is that the smaller the particle diameter of organosilicon micropowder, the greater the number of particles for the same mass, the more light is deflected when passing through it, the greater the diffusivity, and the higher the haze. However, if the particle size is too small, the particle size distribution is difficult to control, resulting in a slight decrease in transmittance at the same haze. Therefore, when the average diameter d of organosilicon micropowder is 0.5-10μm, the powder haze value is higher and the transmittance is better.

[0034] Optionally, in order to further improve the optical properties of the organosilicon powder, the maximum diameter of the polysiloxane microspheres in the organosilicon powder is d max , the minimum diameter is d min ,(d max -d min ) / d×100%≤20% (difference between big and small balls x).

[0035] (d max -d min ) / d×100% can measure the size distribution of organosilicon powder. The smaller the value, the smaller the difference between the largest and smallest sizes of organosilicon powder particles. max -d min ) / d×100%≤20%, it basically reflects that there is no obvious problem of large and small balls in the organosilicon micropowder, and there is no need to control the average diameter of the microspheres to be smaller.

[0036] An embodiment of the present invention provides a method for preparing organosilicon micropowder, comprising: Providing a hydrolyzate, wherein the hydrolyzate is obtained by reacting siloxane and water in a mass ratio of 1:3 to 20, and the conductivity of the hydrolyzate is 3 to 20 μS / cm; providing a mixed solution, mixing the hydrolyzed solution and a base to obtain a mixed solution having a pH of 9 to 11.5; The temperature of the mixed solution is raised to a polycondensation temperature of 40 to 60°C. During the temperature raising process, the time taken for the mixed solution to reach the polycondensation temperature from 0°C is controlled to be ≤ 60s, so that the substances in the mixed solution undergo a polycondensation reaction. After the reaction is completed, a solid-liquid mixture containing polysiloxane microspheres is obtained. The polysiloxane microspheres are extracted from the solid-liquid mixture to obtain organosilicon micropowder.

[0037] In the preparation method provided by the present invention, the hydrolyzate is obtained by the reaction of siloxane and water. After the siloxane and water are mixed, the siloxane will hydrolyze to generate a substance with a low degree of cross-linking (the solution system is colorless and transparent). The conductivity can reflect the degree of hydrolysis of the siloxane in the hydrolyzate to a certain extent. If the degree of hydrolysis of the siloxane is too high (the conductivity is too high), the consistency of the cross-linking degree of the hydrolyzed product may be poor, which will lead to poor size uniformity of the final microspheres. If the degree of hydrolysis of the siloxane is too low (the conductivity is too low), the siloxane molecules fail to fully form active silanols (Si-OH), resulting in insufficient active sites for the subsequent polycondensation reaction. At this time, the polycondensation rate is uneven, resulting in the surface of the prepared microspheres being rough and relatively smooth. The alkaline environment (pH 9~11.5) deprotonates the silanols (Si-OH) in the hydrolyzate to form highly active silanol anions ( ), its charge repulsion inhibits inter-nuclear agglomeration. At the same time, at low temperature (≤0℃), the molecular thermal motion energy is reduced, the collision probability of silanol anions is reduced, the nucleation induction period is prolonged, the excessive catalysis of OH⁻ on condensation is inhibited, and local explosive nucleation is avoided; then the temperature is quickly raised to an appropriate temperature to cause the hydrolyzate in the mixture to undergo a condensation reaction to form polysiloxane microspheres with high surface smoothness and good size uniformity in the solution system.

[0038] The preparation method is specifically as follows: S1. Provide hydrolyzate Siloxane and water are mixed and reacted in a mass ratio of 1:3 to 20 (e.g., 1:3, 1:5, 1:10, 1:15, or 1:20), and stirred to obtain a uniform, transparent hydrolyzate having a conductivity of 3 to 20 μS / cm (e.g., 3 μS / cm, 5 μS / cm, 10 μS / cm, 15 μS / cm, or 20 μS / cm).

[0039] Optionally, the mixing reaction temperature is 20-30°C (20°C, 25°C, or 30°C), and the mixing reaction time is 0.5-3 hours. At this reaction temperature and time, a hydrolyzate having a conductivity in the range of 3-20 μS / cm can be obtained.

[0040] Preferably, the conductivity of the hydrolyzed solution is 4 to 15 μS / cm (e.g., 4 μS / cm, 8 μS / cm, 12 μS / cm, or 15 μS / cm). When the conductivity of the hydrolyzed solution is within this range, polysiloxane microspheres with better size uniformity and relatively smoother surface can be obtained.

[0041] Optionally, the siloxane is selected from at least one of methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane and vinyltrimethoxysilane.

[0042] S2. Provide mixed liquid The hydrolyzate is mixed with an alkali at ≤0°C to obtain a mixture with a pH value of 9 to 11.5 (e.g., 9, 9.5, 10, 10.5, 11, or 11.5). The hydrolyzate and the alkali are mixed to produce a nucleation reaction. If the temperature is too high, the reaction rate is fast, which can easily lead to uneven nucleation. When the mixing temperature is controlled at ≤0°C, the problem of uneven nucleation can be avoided. The amount of alkali added in this process is inversely correlated with the size of the nuclei formed. Increasing the amount of alkali will increase the OH⁻ concentration of the system, resulting in more ionized silanol groups ( ), the density of nucleation sites increases; when the monomer supply remains unchanged, the raw material obtained from a single nucleus decreases, and the final particle size decreases. Therefore, to ensure that the size and size uniformity of the produced polysiloxane microspheres are within the range required by the present invention, the amount of base added is based on the pH value of the resulting mixed solution reaching 9 to 11.5.

[0043] Optionally, in order to better ensure uniform dispersion of the alkali and better quality of the prepared organosilicon micropowder, the alkali is added in the form of an alkali solution.

[0044] Optionally, the alkaline solution is at least one of a sodium hydroxide solution and a potassium hydroxide solution.

[0045] Optionally, the alkaline solution is an aqueous solution of sodium hydroxide, and its mass concentration is 0.08-5% (eg, 0.08%, 0.1%, 0.15%, 0.2%, 0.4% or 0.5%).

[0046] Because the higher the pH value, the more OH added per unit volume - The more the amount, the more nucleation reaction will occur when the base is added to the hydrolyzate. Therefore, if the pH needs to be adjusted to a larger value, in order to ensure the uniformity of nucleation, the base is preferably mixed with the hydrolyzate in batches. After each batch is mixed evenly, the next batch is mixed again.

[0047] Specifically, a flow mixer can be used to mix the alkaline solution with the hydrolyzed solution. For example, the alkaline solution can be mixed in batches by passing the alkaline solution through the flow mixer N times (1 ≤ N ≤ 5) to mix with the hydrolyzed solution. The total mixing time can be controlled within 20 seconds to 3 minutes (e.g., 20 seconds, 1 minute, 2 minutes, or 3 minutes).

[0048] Optionally, the flow rate ratio of the hydrolyzate and the alkaline solution through the mixer is (5-100):1 (e.g., 5:1, 10:1, 20:1, 50:1, 80:1 or 100:1).

[0049] S3, polycondensation reaction The temperature of the mixed solution is raised to a polycondensation temperature of 40 to 60°C (e.g., 40°C, 50°C, or 60°C). During the heating process, the time taken for the mixed solution to reach the polycondensation temperature from 0°C is controlled to be ≤ 60s, so that the substances in the mixed solution undergo a polycondensation reaction. After the reaction is completed, a solid-liquid mixture containing polysiloxane microspheres is obtained.

[0050] The polycondensation temperature needs to be between 40 and 60°C. If the temperature is too low, the polycondensation reaction kinetics are limited, and the silanol (Si-OH) condensation rate is too slow, resulting in insufficient cross-linking on the microsphere surface. This leads to a porous or loose structure and an increase in residual silanol groups. This reduces the mechanical strength of the microspheres, reduces the molecular chain mobility, and prevents surface tension from effectively repairing defects, resulting in a rough surface. If the temperature is too high, the polycondensation reaction is intense, triggering side reactions: The siloxane backbone rearranges, causing stress cracks within the microspheres; volatile small molecules (such as H2O / ROH) rapidly escape, forming internal bubbles and reducing mechanical strength; and if the temperature is too high, inter-core aging is intensified, resulting in a wide particle size distribution and poor uniformity.

[0051] As the temperature rises, the polycondensation reaction gradually begins. A faster temperature rise is more conducive to producing microspheres with a smooth surface and high size uniformity. When the temperature rise time from 0°C to the polycondensation temperature is ≤ 60 seconds, the microspheres produced can meet the requirements for relative surface smoothness and relative size uniformity.

[0052] Optionally, the polycondensation reaction time is controlled to be 0.5 to 1.5 h (eg, 0.5 h, 1 h, or 1.5 h) to ensure sufficient reaction.

[0053] Optionally, the heating time is 30-42 seconds (e.g., 30 seconds, 35 seconds, 40 seconds, or 42 seconds), which is the optimal heating time for preparing microspheres of better quality.

[0054] Optionally, the heating rate is 60-100°C / min (eg, 60°C / min, 70°C / min, 80°C / min, 90°C / min, or 100°C / min).

[0055] Alternatively, a microwave reactor may be used to achieve rapid heating.

[0056] Preferably, to ensure sufficient nucleation and faster heating to the polycondensation temperature, the hydrolyzate and the base are mixed at -5 to 0°C (eg, -5°C, -3°C or 0°C).

[0057] S4. Extraction of reaction products The solid-liquid mixture is subjected to solid-liquid separation, and the obtained solid is washed and dried.

[0058] Optionally, washing is to wash the solid product obtained by solid-liquid separation with deionized water for multiple times.

[0059] Optionally, the drying temperature is 80-120° C. (eg, 80° C., 100° C., or 120° C.) Specifically, the drying may be performed using an infrared drying method.

[0060] An embodiment of the present invention provides a light scattering material, comprising the organosilicon micropowder provided by an embodiment of the present invention or the organosilicon micropowder prepared by the preparation method provided by an embodiment of the present invention.

[0061] An embodiment of the present invention provides a silicon dioxide powder, which is obtained by calcining organic silicon micropowder; the organic silicon micropowder is the organic silicon micropowder provided by the embodiment of the present invention or the organic silicon micropowder prepared by the preparation method provided by the embodiment of the present invention.

[0062] The silica powder obtained by calcining the organosilicon powder provided by the present invention as a raw material has high size uniformity, so that when applied to a copper-clad laminate, the silica powder can better ensure uniform electric field distribution of the copper-clad laminate, reduce interface polarization of the copper-clad laminate, and optimize the filler dispersibility of the copper-clad laminate. The silica powder also has good particle surface smoothness, so when applied to the copper-clad laminate, the silica powder can suppress surface defects of the copper-clad laminate, reduce dielectric loss of the copper-clad laminate, and improve breakdown strength and interface bonding strength of the copper-clad laminate.

[0063] The preparation method is specifically as follows: First-stage heat treatment: In the presence of oxygen, heat the organosilicon powder to a temperature of 500-800°C (e.g., 500°C, 600°C, 700°C, or 800°C) and maintain this temperature for 4-10 hours (e.g., 4 hours, 6 hours, 8 hours, or 10 hours). Optionally, the heating rate in this step is 1-5°C / min (e.g., 1°C / min, 3°C / min, or 5°C / min).

[0064] Second-stage heat treatment: Continue heating to 850-1100°C (e.g., 850°C, 900°C, 950°C, 1000°C, or 1100°C) and hold for 4-10 hours (e.g., 4 hours, 6 hours, 8 hours, or 10 hours). Optionally, the heating rate in this step is 5-10°C / min (e.g., 5°C / min, 8°C / min, or 10°C / min).

[0065] Finally, the temperature is lowered to room temperature. Optionally, the cooling rate is 10-20°C / min, for example (10°C / min, 15°C / min, or 20°C / min).

[0066] The dielectric loss of the finally prepared spherical inorganic silica powder is 0.00015~0.0003.

[0067] An embodiment of the present invention further provides a copper clad laminate, the components of which include the silicon dioxide powder provided by the embodiment of the present invention.

[0068] The present invention will be described below with reference to more specific embodiments: Example 1 S1: Methyltrimethoxysilane was mixed with water and hydrolyzed to obtain a homogeneous and transparent hydrolyzate. The mass ratio of methyltrimethoxysilane to water was 1:10, the mixing temperature was controlled at 20°C, the stirring time was 0.5h, and the conductivity of the hydrolyzate was 4.3μS / cm; S2: The hydrolyzed liquid and the alkali solution (aqueous solution of sodium hydroxide, with a mass concentration of 0.15%) were mixed uniformly at -4°C to obtain a mixed solution with a pH of 10.1. The mixing process was performed using a flow mixer, wherein the hydrolyzed liquid and the alkali solution were passed through the flow mixer at a temperature of -4°C at a flow rate ratio of 9.2:1, and the number of passes was N = 1; S3: Rapidly heating the mixed solution to 50°C until the polycondensation reaction is complete, thereby obtaining a solid-liquid mixture containing polysiloxane microspheres; wherein the heating rate is 80°C / min (37.5 seconds from 0°C to 50°C); a microwave reactor is used for rapid heating during the heating process, and the polycondensation reaction time is 1 hour; S4: performing solid-liquid separation on the solid-liquid mixture, washing the obtained solid with deionized water, and then drying at 100° C. to obtain organosilicon fine powder.

[0069] The prepared organic silicon micropowder was tested by atomic force microscopy (AFM) to obtain Rq: root mean square surface roughness; Ra: average surface roughness, and the relative smoothness R=Rq / Ra was calculated; The samples were tested and analyzed by scanning electron microscopy (SEM) to obtain φ: variance; d: average diameter, and the relative size uniformity RSU = 1-φ / d was calculated. 2 .

[0070] Product parameters are shown in Table 1.

[0071] Examples 2 to 8 Examples 2 to 8 are substantially the same as Example 1, with only the specific parameter settings of the preparation process being different. The specific parameter settings are shown in Table 1, and the parameters of the obtained products are shown in Table 1.

[0072] Table 1 Parameters of each embodiment

[0073] As can be seen from Table 1, the preparation method provided by the present invention can produce organosilicon micropowders having a surface relative smoothness R and a relative size uniformity RSU within the required ranges of the present invention.

[0074] The 2D and 3D images of the atomic force microscope of Example 8 are as follows: Figure 4 As shown in the figure, it can be seen that the micronized powder has a high spheroidization rate and good uniformity, and the surface is smooth as shown in the 3D figure.

[0075] Comparative Example The preparation method of the comparative example is basically the same as that of Example 1, and the differences are shown in Table 2.

[0076] Table 2 Parameters of each comparative example

[0077] It can be seen from Table 2 that at least one of the surface relative smoothness R and the relative size uniformity RSU of the organosilicon powder prepared in each comparative example is outside the range required by the present invention.

[0078] Compared to Example 2, Comparative Example 1 increased the siloxane-to-water ratio, exceeding the requirements of the present invention. The conductivity of the hydrolyzed solution also exceeded the requirements of the present invention. SEM images of the resulting organosilicon micropowder showed poor particle size uniformity and the presence of some surface pits. The size difference between the large and small spheres was 7.1 μm.

[0079] Comparing Comparative Example 2 with Example 3, the ratio of siloxane to water is increased, which exceeds the required range of the present invention. The conductivity of the hydrolyzed solution also exceeds the required range of the present invention. Under base catalysis, the condensation rate is more intense, resulting in poor uniformity of the particle size of the prepared organic microspheres.

[0080] Compared with Example 3, in Comparative Example 3, the polycondensation reaction is accelerated by increasing the mixing temperature, and the nucleation and growth are uneven during the temperature increase process, resulting in uneven particle size.

[0081] Compared with Example 2, in Comparative Example 4, the pH of the mixed solution is lower than the range required by the present invention. At low alkali concentrations, the prepolymer is generated slowly and the catalytic active groups are insufficient, resulting in insufficient cross-linking of the molecular chains. Unreacted groups or pores are easily left on the surface of the sphere, reducing the smoothness.

[0082] Compared with Example 3, in Comparative Example 5, the pH of the mixed solution is controlled at 12, which is higher than the range required by the present invention. The catalytic activity is higher, which accelerates the polycondensation rate, resulting in excessive local supersaturation of the reaction system, triggering explosive nucleation; a large number of crystal nuclei are formed instantly, and the molecular chains are stacked disorderly, which reduces the surface roughness of the spheres and the particle size uniformity is poor.

[0083] Compared with Example 2, Comparative Example 6 reduces the heating rate, so that the heating time exceeds the requirements of the present invention. The slow heating prolongs the aging time of the prepolymer, and silanol (Si-OH) undergoes local pre-condensation, causing the molecular layers on the surface of the sphere to be stacked disorderly, forming micron-sized protrusions or pores, and reducing the roughness.

[0084] Compared with Example 2, in Comparative Example 7, the condensation polymerization temperature is lowered. The low temperature causes the condensation polymerization rate to decrease, the asynchronous nucleation phenomenon is prominent, the highly active prepolymer preferentially nucleates to form small particles, and the free monomer slowly attaches to form large particles; and the low-temperature crosslinking is insufficient, the surface molecular orientation is disordered, and the surface is rough.

[0085] Experimental example The organosilicon powders prepared in various examples and comparative examples were used to prepare light scattering materials according to the following preparation method.

[0086] Preparation Method: Silicone micropowder and polycarbonate masterbatch (available from Dongguan Sushishi Polymer Materials Co., Ltd.) are mixed in a weight ratio of 1:100. The mixture is melted, mixed, extruded, water-cooled, and pelletized in a twin-screw extruder. The extruded pellets are dried in a 150°C forced air oven for 3 hours and then injection molded using an injection molding machine to produce a light-scattering material for LED lighting housings. The samples are tested using a transmittance and haze meter according to GB / T2410-2008.

[0087] Pure polycarbonate masterbatch was used as blank control.

[0088] Record the test results in Table 3.

[0089] Table 3 Performance test results of materials prepared in each embodiment, comparative example and blank control group

[0090] It can be seen from Table 3 that the light transmittance of the organosilicon powder prepared in each embodiment provided by the present invention is above 90%, and the haze can reach above 90%.

[0091] In each comparative example, some R values ​​are outside the range required by the present invention, some RSU values ​​are outside the range required by the present invention, and the measured transmittance and haze are significantly worse than those in the examples. This shows that when the relative surface smoothness and relative size uniformity of the organosilicon micropowder are within the range required by the present invention, it can be ensured that when applied to light scattering materials, the light scattering materials have higher transmittance and haze.

[0092] Example 9 This embodiment provides a method for preparing silicon dioxide powder, specifically: The first stage of heat treatment: the organosilicon micropowder prepared in Example 1 is placed in an environment with oxygen, the temperature of the environment in which the organosilicon micropowder is located is raised to 600° C. at a heating rate of 4° C. / min, and the temperature is kept for 6 hours.

[0093] The second stage of heat treatment: continue heating to 1000℃ at a heating rate of 6℃ / min and keep warm for 6h.

[0094] Finally, the temperature was lowered to room temperature at a cooling rate of 15°C / min to obtain silica powder.

[0095] The dielectric loss of the prepared silica powder was tested to be 0.00025, and the results showed that the silica powder after calcination of the organic microspheres had excellent dielectric properties.

[0096] In summary, the organosilicon micropowder provided by the present invention can ensure that its relative smoothness and relative size uniformity are within the range required by the present invention, thereby ensuring that the organosilicon micropowder has high light utilization rate, high light transmittance, and good uniformity of light scattering and diffusion; after being applied to light diffusion materials, the light control precision is high, the light transmittance and diffusion are good, and the light transmittance and brightness are higher; and when used as a raw material for forming a coating, the coating formed has good flatness.

[0097] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An organosilicon micropowder, characterized in that: It is composed of a plurality of polysiloxane microspheres, each of which has a relative surface smoothness of R, 1.02≤R≤1.30, wherein R=Rq / Ra, Rq is the root mean square surface roughness of the polysiloxane microsphere, and Ra is the average surface roughness of the polysiloxane microsphere; The relative size uniformity of the organosilicon powder is RSU, RSU=1-φ / d 2 ≥0.992, wherein φ is the variance of the diameter of the organosilicon micropowder, and d is the average diameter of the organosilicon micropowder.

2. The organosilicon micropowder according to claim 1, characterized in that The root mean square surface roughness Rq of each of the polysiloxane microspheres is ≤120 nm, and the average surface roughness Ra is ≤100 nm.

3. The organosilicon micropowder according to claim 1, characterized in that The root mean square surface roughness of each of the polysiloxane microspheres is 48 nm ≤ Rq ≤ 101.1 nm, and the average surface roughness is 38 nm ≤ Ra ≤ 97.2 nm.

4. The organosilicon micropowder according to claim 1, characterized in that Include at least one of the following features (1) and (2): (1) The average diameter d of the organosilicon powder is 0.5-10 μm; (2) The maximum diameter of the polysiloxane microspheres in the organic silicon micropowder is d max , the minimum diameter is d min ,(d max -d min ) / d×100%≤20%.

5. A method for preparing organosilicon micropowder, characterized in that: include: Providing a hydrolyzate, wherein the hydrolyzate is obtained by reacting siloxane and water in a mass ratio of 1:3 to 20, and the conductivity of the hydrolyzate is 3 to 20 μS / cm; Providing a mixed solution, mixing the hydrolyzed solution and a base at ≤0°C to obtain a mixed solution with a pH of 9 to 11.5; Raising the temperature of the mixed solution to a polycondensation temperature of 40° C. to 60° C., wherein the time taken for the mixed solution to reach the polycondensation temperature from 0° C. during the heating process is controlled to be ≤ 60 seconds, so that the substances in the mixed solution undergo a polycondensation reaction, and the reaction is completed to obtain a solid-liquid mixture containing polysiloxane microspheres; The polysiloxane microspheres are extracted from the solid-liquid mixture to obtain the organosilicon micropowder.

6. The preparation method according to claim 5, characterized in that Also includes at least one of the following features (1) to (7): (1) The siloxane is at least one selected from methyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane and vinyltrimethoxysilane; (2) mixing the hydrolyzate with the alkali at -5 to 0°C; (3) the temperature of the mixed solution is raised to the polycondensation temperature at a rate of 60 to 100°C / min; (4) The base is selected from at least one of sodium hydroxide and potassium hydroxide; (5) The reaction temperature of the siloxane and water is 20-30°C, and the reaction time is 0.5-3h; (6) The alkali is mixed with the hydrolyzate in the form of an alkali solution, and the mixing method is: the alkali solution is divided into multiple batches and mixed with the hydrolyzate in batches; (7) The method of extracting the polysiloxane microspheres from the solid-liquid mixture includes: performing solid-liquid separation on the solid-liquid mixture, and washing and drying the obtained solid.

7. The preparation method according to claim 5, characterized in that The conductivity of the hydrolyzate is 4-15 μS / cm.

8. A light scattering material, characterized in that The method comprises the organic silicon micropowder according to any one of claims 1 to 4 or the organic silicon micropowder prepared by the preparation method according to any one of claims 5 to 7.

9. A silicon dioxide powder, characterized in that: It is obtained by calcining organic silicon micropowder; The organosilicon micropowder is the organosilicon micropowder according to any one of claims 1 to 4 or the organosilicon micropowder prepared by the preparation method according to any one of claims 5 to 7.

10. A copper clad laminate, characterized in that: Its components include the silicon dioxide powder as claimed in claim 9.

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