Preparation method of composite silicon resin micro powder

Abstract

The invention discloses a preparation method of composite silicon resin micro powder, and relates to the technical field of organic and inorganic hybrid materials, and the preparation method comprises the following steps: S1, preparing a phenyl silane premixed solution: adding phenyl silane into a mixed solvent composed of ethanol and pure water, uniformly stirring, adjusting the pH value of the system to 3-5, and stirring at a constant temperature of 30-70 DEG C for 30-60 minutes; s2, preparing a methyl silicate reaction solution: adding water into the methyl silicate solution to dilute the methyl silicate solution until the mass fraction is 2-20%, adding a surfactant, uniformly stirring, controlling the temperature at 30-70 DEG C, and adding acid to adjust the pH value of the system to 8-12. According to the preparation method of the composite silicon resin micro powder, a methyl silicate precursor with a low refractive index and a phenyl silane precursor with a high refractive index are subjected to copolycondensation reaction, and the composite silicon resin micro powder with the refractive index adjustable in the range of 1.42-1.58 is successfully prepared. By adjusting the proportion of the two monomers, the refractive index of the product can be accurately controlled, so that the specific requirements of different application scenes on light transmittance and haze are met.

Description

Technical Field

[0001] This invention relates to the field of organic-inorganic hybrid materials technology, specifically a method for preparing composite silicone resin micro powder. Background Technology

[0002] LEDs have become the mainstream lighting source due to their high luminous efficiency, long lifespan, and small size. However, LED chips are point light sources, and their light is glaring, requiring a light diffuser to convert it into a uniform surface light source. Light diffusers are typically made of plastic substrates such as PC, PS, and PMMA with added light diffusing agents. When light passes through the diffuser, it is scattered by the light diffusing agent particles, thus achieving a uniform light effect. Light diffusion performance is measured by transmittance and haze, which are closely related to the particle size of the light diffusing agent and the difference in refractive index between the light diffusing agent and the substrate.

[0003] Currently, commonly used light diffusing agents include polymethylsilsesquioxane (organosilicon, refractive index approximately 1.42) and polymethyl methacrylate (PMMA, refractive index approximately 1.49). Organosilicon light diffusing agents have a large refractive index difference with commonly used plastic substrates (refractive index approximately 1.56-1.58), resulting in high haze and good light uniformity, but relatively low light transmittance. PMMA light diffusing agents have a small refractive index difference with the substrate, resulting in high light transmittance, but poor heat resistance and a tendency to yellow during processing. Existing technologies cannot simultaneously achieve high light transmittance, excellent heat resistance, and adjustable light diffusion effects. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing composite silicone resin micro powder to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing composite silicone resin micro powder, comprising the following steps: S1. Preparation of phenylsilane premix: Add phenylsilane to a mixed solvent consisting of ethanol and pure water, stir evenly, adjust the pH of the system to 3~5, and stir at a constant temperature of 30~70℃ for 30~60 minutes. S2. Preparation of methylsilicate reaction solution: Dilute the methylsilicate solution with water to a mass fraction of 2%~20%, add surfactant, stir evenly, control the temperature at 30~70℃, and add acid to adjust the pH value of the system to 8~12; S3, Cocondensation reaction: Add the phenylsilane premix obtained in step S1 to the methylsilicate reaction solution obtained in step S2, mix evenly, control the pH of the reaction system to 7~10, and stir at 30~70℃ for 1~4 hours. S4. Neutralization and post-treatment: Add acid to the reaction system of step S3 to adjust the pH value to 6-7, and then filter, wash with water and dry to obtain the white powdered composite silicone resin micro powder.

[0006] Furthermore, in step S1, the phenylsilane is selected from one or more of phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

[0007] Furthermore, in step S1, the mass ratio of ethanol to pure water in the mixed solvent is 1:100 to 1:25.

[0008] Furthermore, in step S1, the mass ratio of the phenylsilane to the mixed solvent is 1:4 to 1:15.

[0009] Furthermore, in step S2, the methylsilicate is selected from sodium methylsilicate or potassium methylsilicate.

[0010] Furthermore, in step S2, the surfactant is a nonionic surfactant or anionic surfactant; the amount of the surfactant added accounts for 0.1% to 10% of the total mass of the reaction mixture in step S2.

[0011] Furthermore, the nonionic surfactant is selected from one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and fatty acid polyoxyethylene ester; the anionic surfactant is selected from one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecyl polyoxyethylene ether sulfate, and potassium dodecyl phosphate.

[0012] This invention provides a method for preparing composite silicone resin micro powder, which has the following beneficial effects: This invention successfully prepared composite silicone resin micropowder with an adjustable refractive index in the range of 1.42 to 1.58 by co-condensation reaction of a low-refractive-index methylsilicate precursor and a high-refractive-index phenylsilane precursor. By adjusting the ratio of the two monomers, the refractive index of the product can be precisely controlled, thereby meeting the specific requirements of different application scenarios for transmittance and haze.

[0013] The composite silicone resin micro powder prepared by this invention not only retains the excellent heat resistance, weather resistance and chemical stability inherent in organosilicon materials, but also improves the refractive index by introducing phenyl groups, thus overcoming the shortcomings of poor heat resistance of traditional PMMA-type light diffusing agents. Attached Figure Description

[0014] Figure 1 The particle size distribution diagram is shown for the composite silicone resin micro powder prepared in Example 1. Figure 2 SEM image of the composite silicone resin micropowder prepared in Example 1; Figure 3 The particle size distribution diagram is shown for the composite silicone resin micro powder prepared in Example 2. Figure 4 SEM image of the composite silicone resin micropowder prepared in Example 2; Figure 5 The particle size distribution diagram is shown for the composite silicone resin micro powder prepared in Example 3. Figure 6 This is an SEM image of the composite silicone resin micropowder prepared in Example 3. Detailed Implementation

[0015] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Example 1

[0016] S1: Add 27g of pure water, 3g of ethanol, and 0.15g of 1mol / L hydrochloric acid solution to a 50ml beaker. Stir well with a magnetic stirrer, add 3.7g of diphenyldimethoxysilane, wrap the mouth of the beaker with aluminum foil, place it in a water bath with magnetic stirring, heat at 40℃, and stir for 60 minutes.

[0017] S2: Add 135g of a 35% sodium methylsilicate aqueous solution to a 1L flask, add 600g of pure water, then add 1g of sodium dodecyl sulfate, stir, heat in a water bath to 40℃, and stir at a constant temperature for 10 minutes. Add 16g of 1mol / L hydrochloric acid solution, and measure the pH of the reaction system to be 9.3.

[0018] S3: Add the mixture prepared in S1 to the flask in S2 and stir at a constant temperature of 40°C for 3 hours.

[0019] S4: Adjust the pH of the reactants to 6-7 with 1 mol / L hydrochloric acid solution, filter, wash with water, and dry at 100℃ to obtain a white powder product. The average particle size was 5.070 μm, the particle size distribution span was 0.621, and the refractive index was 1.44. Example 2

[0020] S1: Add 270g of pure water, 30g of ethanol, and 1.5g of 1mol / L hydrochloric acid solution to a 500ml three-necked flask. Stir well, add 36.4g of phenyltriethoxysilane, heat in a 40℃ water bath, and stir for 60 minutes.

[0021] S2: Add 70g of a 35% sodium methylsilicate aqueous solution to a 1L flask, add 370g of pure water, then add 3g of OP-10 (dodecylphenol polyoxyethylene ether), stir, heat in a water bath to 40℃, and stir at a constant temperature for 10 minutes. Add 8.3g of 1mol / L hydrochloric acid solution, and measure the pH of the reaction system to be 9.2.

[0022] S3: Add the mixture prepared in S1 to the flask in S2 and stir at a constant temperature of 40°C for 3 hours.

[0023] S4: Adjust the pH of the reactants to 6-7 with 1 mol / L hydrochloric acid solution, filter, wash with water, and dry at 100℃ to obtain a white powder product. The average particle size was 3.025 micrometers, the particle size distribution span was 0.642, and the refractive index was 1.51. Example 3

[0024] S1: Add 576g of pure water, 60g of ethanol, and 3g of 1mol / L hydrochloric acid solution to a 1L three-necked flask. Stir well, then add 60g of phenyltrimethoxysilane. Heat in a 40℃ water bath and stir for 60 minutes. Then add 3g of 1mol / L NaOH solution and stir for 2 minutes.

[0025] S2: Add 5g of a 35% sodium methylsilicate aqueous solution and 80g of pure water to a 1L flask, then add 1g of sodium dodecyl sulfate. Stir, heat in a water bath to 40℃, and stir for 10 minutes. The pH of the reaction system is measured to be 11.8.

[0026] S3: Add the mixture prepared in S1 to the flask in S2 and stir at a constant temperature of 40°C for 3 hours.

[0027] S4: Adjust the pH of the reactants to 6-7 with 1 mol / L hydrochloric acid solution, filter, wash with water, and dry at 100℃ to obtain a white powder product. The average particle size was 1.912 micrometers, the particle size distribution span was 0.549, and the refractive index was 1.56.

[0028] The refractive index results of the micropowders prepared in each embodiment are shown in the table below:

[0029] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for preparing composite silicone resin micro powder, characterized in that, Includes the following steps: S1. Preparation of phenylsilane premix: Add phenylsilane to a mixed solvent consisting of ethanol and pure water, stir evenly, adjust the pH of the system to 3~5, and stir at a constant temperature of 30~70℃ for 30~60 minutes. S2. Preparation of methylsilicate reaction solution: Dilute the methylsilicate solution with water to a mass fraction of 2%~20%, add surfactant, stir evenly, control the temperature at 30~70℃, and add acid to adjust the pH value of the system to 8~12; S3, Cocondensation reaction: Add the phenylsilane premix obtained in step S1 to the methylsilicate reaction solution obtained in step S2, mix evenly, control the pH of the reaction system to 7~10, and stir at 30~70℃ for 1~4 hours. S4. Neutralization and post-treatment: Add acid to the reaction system of step S3 to adjust the pH value to 6-7, and then filter, wash with water and dry to obtain the white powdered composite silicone resin micro powder.

2. The method for preparing composite silicone resin micro powder according to claim 1, characterized in that, In step S1, the phenylsilane is selected from one or more of phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, and diphenyldiethoxysilane.

3. The method for preparing composite silicone resin micro powder according to claim 1, characterized in that, In step S1, the mass ratio of ethanol to pure water in the mixed solvent is 1:100 to 1:

25.

4. The method for preparing composite silicone resin micro powder according to claim 3, characterized in that, In step S1, the mass ratio of the phenylsilane to the mixed solvent is 1:4 to 1:

15.

5. The method for preparing composite silicone resin micro powder according to claim 3, characterized in that, In step S2, the methylsilicate is selected from sodium methylsilicate or potassium methylsilicate.

6. The method for preparing composite silicone resin micro powder according to claim 1, characterized in that, In step S2, the surfactant is a nonionic surfactant or anionic surfactant; the amount of surfactant added accounts for 0.1% to 10% of the total mass of the reaction mixture in step S2.

7. The method for preparing composite silicone resin micro powder according to claim 6, characterized in that, The nonionic surfactant is selected from one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and fatty acid polyoxyethylene ester; the anionic surfactant is selected from one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecyl polyoxyethylene ether sulfate, and potassium dodecyl phosphate.

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