Preparation method of hydrophobic synthetic mica

Abstract

The invention discloses a preparation method of hydrophobic synthetic mica. According to the hydrophobic synthetic mica disclosed by the invention, firstly, the synthetic mica is pretreated to enable the periphery of the synthetic mica to have hydroxyl groups, and then the hydroxyl groups around the synthetic mica and Si-OH groups in a hydrolyzed coupling agent are subjected to condensation reaction, so that amino groups are introduced to the surface of the synthetic mica, and the dispersity and compatibility of the synthetic mica are improved; and secondly, the amino group introduced on the surface can be subjected to esterification reaction with the carboxyl group in the fluorine-containing hyperbranched polymer, so that fluorine-terminated alkyl is introduced on the surface of the synthetic mica, and the hydrophobicity of the synthetic mica is improved. The hydrophobic synthetic mica prepared by the invention can be used as a filler in materials such as coatings, plastics, rubber and the like, and can improve the compatibility in a matrix and improve the hydrophobic property of the matrix.

Description

Technical Field

[0001] The invention relates to the field of synthetic mica preparation, and in particular to a method for preparing hydrophobic synthetic mica. Background Art

[0002] Synthetic mica, also known as artificial mica, belongs to silicate compounds. Its raw materials include silicon dioxide, aluminum hydroxide, fluoride, magnesium oxide, aluminum oxide, etc., which are heated to high temperature and melted, and then cooled and crystallized. Compared with natural mica, synthetic mica has high surface finish, high whiteness, high purity, and does not contain heavy metals that are harmful to the human body. It is widely used in coatings, rubber, cosmetics, electrical appliances and other industries. However, the surface of synthetic mica is highly hydrophilic, and the water molecule layer near the surface of mica is relatively dense, which leads to poor compatibility between synthetic mica and polymer matrix materials, greatly limiting its application in cosmetics, rubber, plastics and coatings. Therefore, it is necessary to perform surface modification on synthetic mica. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method for preparing hydrophobic synthetic mica.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing hydrophobic synthetic mica comprises the following steps: Step S1, stirring and mixing synthetic mica and deionized water, then adding ammonium bicarbonate, stirring for 5-10 minutes, vacuum filtering, placing in a drying oven at 150° C. for drying and calcining for 3 hours, then adding 3-aminopropyltrimethylsilane solution, stirring for 30-60 minutes, standing for 1 hour, vacuum filtering, placing at 60° C. for vacuum drying for 6 hours, and obtaining amino-compounded synthetic mica; Further, the mass ratio of synthetic mica, 3-aminopropyltrimethylsilane solution and deionized water is 1:9:20; Further, the mass ratio of 3-aminopropyltrimethylsilane, deionized water and methanol in the 3-aminopropyltrimethylsilane solution is 1:1:9; Step S2, adding the fluorine-containing hyperbranched polymer to a reactor containing deionized water, ultrasonically dispersing for 30 minutes, and cooling to 0°C in an ice-water bath, then sequentially adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide to the reactor, mixing and stirring for 1 hour, then adding the amino synthetic mica aqueous solution, stirring for 8-12 hours in an ice-water bath, after the reaction is completed, filtering, washing three times, and vacuum drying at 60°C for 6 hours to obtain hydrophobic synthetic mica; Further, the mass ratio of the fluorinated hyperbranched polymer, deionized water, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide and the amino-synthesized mica aqueous solution is 5-10 g: 50 g: 0.01-0.05 g: 0.01-0.05 g: 50 g; Furthermore, the mass ratio of the aminated synthetic mica to deionized water in the aminated synthetic mica aqueous solution is 1:10.

[0005] The fluorine-containing hyperbranched polymer is prepared by the following steps: Step A1, add succinic anhydride to a reactor containing N, N-dimethylacetamide, mix and stir for 30 minutes, then add diisopropanolamine, raise the temperature to 70°C, react for 0.5-1.5 hours, after the reaction is completed, remove the solvent by distillation under reduced pressure, and vacuum dry at 80°C for 12 hours to obtain intermediate 1; In step A1, succinic anhydride is ring-opened under alkaline conditions to form two carboxyl groups, one of which reacts with the secondary amine in diisopropanolamine to introduce a hydroxyl group into the system, and the other carboxyl group can react with the amino group in the coupling agent, thereby grafting the fluorine-containing hyperbranched polymer onto the surface of the synthetic mica, thereby improving the hydrophobicity of the synthetic mica; Furthermore, the usage ratio of succinic anhydride, diisopropanolamine and N,N-dimethylacetamide is 0.01-0.03 mol: 0.01-0.03 mol: 10 mL.

[0006] Step A2, adding intermediate 1, p-toluenesulfonic acid and toluene into a reactor containing N, N-dimethylformamide, stirring and mixing, slowly dropping glycine N, N-dimethylformamide solution, heating to 140°C and reacting under stirring for 5 hours, after the reaction is completed, standing and cooling the mixture, washing with deionized water, filtering, and drying in a vacuum drying oven at 60°C for 24 hours to obtain intermediate 2; In step A2, the carboxyl group on glycine undergoes an esterification reaction with the hydroxyl group on the intermediate 1, introducing the amino group into the system so that it can react with the carboxyl group in the subsequent reaction; Furthermore, the dosage ratio of intermediate 1, p-toluenesulfonic acid and toluene, N,N-dimethylformamide and glycine N,N-dimethylformamide solution is 0.05-0.1 mol: 0.06-0.1 g: 22-25 mL: 20 mL: 40 mL, and the dosage ratio of glycine and N,N-dimethylformamide in the glycine N,N-dimethylformamide solution is 0.1-0.2 mol: 40 mL.

[0007] Step A3, adding 4-trifluoromethylphenylacetic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide to a reactor containing N,N-dimethylformamide, mixing and stirring for 0.5-1.5h, adjusting the pH to 5, then adding intermediate 2, stirring for 5-7h, after the reaction is completed, removing the solvent by rotary evaporation, and vacuum drying at 80°C for 24h to obtain a fluorine-containing hyperbranched polymer; In step A3, the carboxyl group on 4-trifluoromethylphenylacetic acid reacts with the amino group on intermediate 2 to undergo an amidation reaction, thereby introducing a benzene ring and a terminal fluorocarbon. The terminal fluorocarbon at the end of the hyperbranched polymer is easy to migrate to and accumulate on the surface of the substrate because the fluorine atom has a small atomic radius, a strong electronegativity, and a high CF bond energy, thereby reducing the surface energy of the substrate and improving the hydrophobicity of the substrate. In addition, since the benzene ring only has a carbon chain, it is also hydrophobic. Furthermore, the usage ratio of intermediate 2, p-toluenesulfonic acid, 4-trifluoromethylphenylacetic acid and N,N-dimethylformamide is 0.025-0.04 mol: 0.08-0.15 g: 0.05-0.08 mol: 100 mL.

[0008] Beneficial effects of the present invention: The invention provides a method for preparing hydrophobic synthetic mica. Firstly, the synthetic mica is pretreated so that hydroxyl groups are formed around the synthetic mica, and then the hydroxyl groups around the synthetic mica are subjected to condensation reaction with Si-OH groups in a hydrolyzed coupling agent, thereby introducing amino groups on the surface of the synthetic mica, thereby improving the dispersibility and compatibility of the synthetic mica; secondly, the amino groups introduced on the surface can undergo esterification reaction with carboxyl groups in a fluorine-containing hyperbranched polymer, thereby introducing terminal fluorocarbons on the surface of the synthetic mica, thereby improving the hydrophobicity of the synthetic mica.

[0009] The hydrophobic synthetic mica prepared by the invention can be used as filler in materials such as coatings, plastics, rubbers, etc., and can improve the hydrophobicity of the substrate. DETAILED DESCRIPTION

[0010] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example

[0011] A method for preparing hydrophobic synthetic mica comprises the following steps: Step S1, stirring and mixing synthetic mica and deionized water, then adding ammonium bicarbonate, stirring for 5 minutes, vacuum filtering, placing in a 150° C. drying oven for 3 hours, then adding 3-aminopropyltrimethylsilane solution, stirring for 30 minutes, standing for 1 hour, vacuum filtering, placing at 60° C. and vacuum drying for 6 hours to obtain amino-compounded synthetic mica, wherein the mass ratio of synthetic mica, 3-aminopropyltrimethylsilane solution and deionized water is 1:9:20, and the mass ratio of 3-aminopropyltrimethylsilane, deionized water and methanol in the 3-aminopropyltrimethylsilane solution is 1:1:9; Step S2, adding the fluorine-containing hyperbranched polymer to a reactor containing deionized water, ultrasonically dispersing for 30 minutes, and cooling to 0°C in an ice-water bath, then adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide to the reactor in sequence, mixing and stirring for 1 hour, then adding the amino synthetic mica aqueous solution, stirring for 8 hours under ice-water bath conditions, after the reaction is completed, filtering, washing three times, and vacuum drying at 60°C for 6 hours to obtain hydrophobic synthetic mica, the mass ratio of the fluorine-containing hyperbranched polymer, deionized water, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide and the amino synthetic mica aqueous solution is 5g:50g:0.01g:0.01g:50g, and the mass ratio of the amino synthetic mica and deionized water in the amino synthetic mica aqueous solution is 1:10.

[0012] The fluorinated hyperbranched polymer is prepared by the following steps: Step A1, add succinic anhydride to a reactor containing N, N-dimethylacetamide, mix and stir for 30 minutes, then add diisopropanolamine, raise the temperature to 70°C, react for 0.5h, after the reaction is completed, remove the solvent by reduced pressure distillation, and vacuum dry at 80°C for 12h to obtain intermediate 1, wherein the amount ratio of succinic anhydride, diisopropanolamine and N, N-dimethylacetamide is 0.01mol:0.01mol:10mL; Step A2, add intermediate 1, p-toluenesulfonic acid and toluene to a reactor containing N, N-dimethylformamide, stir and mix evenly, then slowly dropwise add glycine N, N-dimethylformamide solution, heat to 140°C and react for 5 hours under stirring. After the reaction is completed, let the mixture stand and cool, wash with deionized water, filter, and dry in a vacuum drying oven at 60°C for 24 hours to obtain intermediate 2. The amount ratio of intermediate 1, p-toluenesulfonic acid and toluene, N, N-dimethylformamide and glycine N, N-dimethylformamide solution is 0.05 mol: 0.06 g: 22 mL: 20 mL: 40 mL, and the amount ratio of glycine and N, N-dimethylformamide in the glycine N, N-dimethylformamide solution is 0.1 mol: 40 mL; Step A3, 4-trifluoromethylphenylacetic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added to a reactor containing N,N-dimethylformamide, mixed and stirred for 0.5h, the pH is adjusted to 5, and then the intermediate 2 is added, and stirring is continued for 5h. After the reaction is completed, the solvent is removed by rotary evaporation, and vacuum dried at 80°C for 24h to obtain a fluorine-containing hyperbranched polymer, and the amount ratio of intermediate 2, p-toluenesulfonic acid, 4-trifluoromethylphenylacetic acid and N,N-dimethylformamide is 0.025mol:0.08g:0.05mol:100mL. Example

[0013] A method for preparing hydrophobic synthetic mica comprises the following steps: Step S1, stirring and mixing synthetic mica and deionized water, then adding ammonium bicarbonate, stirring for 7 minutes, vacuum filtering, placing in a 150° C. drying oven for 3 hours, then adding 3-aminopropyltrimethylsilane solution, stirring for 45 minutes, standing for 1 hour, vacuum filtering, placing at 60° C. and vacuum drying for 6 hours to obtain amino-compounded synthetic mica, wherein the mass ratio of synthetic mica, 3-aminopropyltrimethylsilane solution and deionized water is 1:9:20, and the mass ratio of 3-aminopropyltrimethylsilane, deionized water and methanol in the 3-aminopropyltrimethylsilane solution is 1:1:9; Step S2, adding the fluorine-containing hyperbranched polymer to a reactor containing deionized water, ultrasonically dispersing for 30 minutes, and cooling to 0°C in an ice-water bath, then adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide to the reactor in sequence, mixing and stirring for 1 hour, then adding the amino synthetic mica aqueous solution, stirring for 10 hours under ice-water bath conditions, after the reaction is completed, filtering, washing three times, and vacuum drying at 60°C for 6 hours to obtain hydrophobic synthetic mica, the mass ratio of the fluorine-containing hyperbranched polymer, deionized water, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide and the amino synthetic mica aqueous solution is 7g:50g:0.03g:0.03g:50g, and the mass ratio of the amino synthetic mica and deionized water in the amino synthetic mica aqueous solution is 1:10.

[0014] The fluorinated hyperbranched polymer is prepared by the following steps: Step A1, add succinic anhydride to a reactor containing N, N-dimethylacetamide, mix and stir for 30 minutes, then add diisopropanolamine, raise the temperature to 70°C, react for 1 hour, after the reaction is completed, remove the solvent by reduced pressure distillation, and vacuum dry at 80°C for 12 hours to obtain intermediate 1, wherein the amount ratio of succinic anhydride, diisopropanolamine and N, N-dimethylacetamide is 0.02 mol: 0.02 mol: 10 mL; Step A2, add intermediate 1, p-toluenesulfonic acid and toluene to a reactor containing N, N-dimethylformamide, stir and mix evenly, then slowly dropwise add glycine N, N-dimethylformamide solution, heat to 140°C and react for 5 hours under stirring conditions. After the reaction is completed, the mixture is allowed to stand and cool, washed with deionized water, filtered, and dried in a vacuum drying oven at 60°C for 24 hours to obtain intermediate 2. The amount ratio of intermediate 1, p-toluenesulfonic acid and toluene, N, N-dimethylformamide and glycine N, N-dimethylformamide solution is 0.075 mol: 0.08 g: 23 mL: 20 mL: 40 mL, and the amount ratio of glycine and N, N-dimethylformamide in the glycine N, N-dimethylformamide solution is 0.15 mol: 40 mL; Step A3, 4-trifluoromethylphenylacetic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added to a reactor containing N, N-dimethylformamide, mixed and stirred for 0.5-1.5h, the pH is adjusted to 5, and then the intermediate 2 is added, and stirring is continued for 6h. After the reaction is completed, the solvent is removed by rotary evaporation, and vacuum dried at 80°C for 24h to obtain a fluorine-containing hyperbranched polymer, and the amount ratio of intermediate 2, p-toluenesulfonic acid, 4-trifluoromethylphenylacetic acid and N, N-dimethylformamide is 0.035mol:0.12g:0.07mol:100mL. Example

[0015] A method for preparing hydrophobic synthetic mica comprises the following steps: Step S1, stirring and mixing synthetic mica and deionized water, then adding ammonium bicarbonate, stirring for 10 minutes, vacuum filtering, placing in a 150° C. drying oven for 3 hours, then adding 3-aminopropyltrimethylsilane solution, stirring for 60 minutes, standing for 1 hour, vacuum filtering, placing at 60° C. and vacuum drying for 6 hours to obtain amino-compounded synthetic mica, wherein the mass ratio of synthetic mica, 3-aminopropyltrimethylsilane solution and deionized water is 1:9:20, and the mass ratio of 3-aminopropyltrimethylsilane, deionized water and methanol in the 3-aminopropyltrimethylsilane solution is 1:1:9; Step S2, adding the fluorine-containing hyperbranched polymer to a reactor containing deionized water, ultrasonically dispersing for 30 minutes, and cooling to 0°C in an ice-water bath, then adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide to the reactor in sequence, mixing and stirring for 1 hour, then adding the amino synthetic mica aqueous solution, stirring for 12 hours under ice-water bath conditions, after the reaction is completed, filtering, washing three times, and vacuum drying at 60°C for 6 hours to obtain hydrophobic synthetic mica, the mass ratio of the fluorine-containing hyperbranched polymer, deionized water, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide and the amino synthetic mica aqueous solution is 10g:50g:0.05g:0.05g:50g, and the mass ratio of the amino synthetic mica and deionized water in the amino synthetic mica aqueous solution is 1:10.

[0016] The fluorinated hyperbranched polymer is prepared by the following steps: Step A1, adding succinic anhydride to a reactor containing N, N-dimethylacetamide, mixing and stirring for 30 minutes, then adding diisopropanolamine, raising the temperature to 70°C, reacting for 0.5-1.5 hours, after the reaction is completed, removing the solvent by distillation under reduced pressure, and vacuum drying at 80°C for 12 hours to obtain intermediate 1, wherein the amount ratio of succinic anhydride, diisopropanolamine and N, N-dimethylacetamide is 0.03 mol: 0.03 mol: 10 mL; Step A2, add intermediate 1, p-toluenesulfonic acid and toluene to a reactor containing N, N-dimethylformamide, stir and mix evenly, then slowly dropwise add glycine N, N-dimethylformamide solution, heat to 140°C and react for 5 hours under stirring conditions. After the reaction is completed, the mixture is allowed to stand and cool, washed with deionized water, filtered, and dried in a vacuum drying oven at 60°C for 24 hours to obtain intermediate 2. The amount ratio of intermediate 1, p-toluenesulfonic acid and toluene, N, N-dimethylformamide and glycine N, N-dimethylformamide solution is 0.1 mol: 0.1 g: 25 mL: 20 mL: 40 mL, and the amount ratio of glycine and N, N-dimethylformamide in the glycine N, N-dimethylformamide solution is 0.2 mol: 40 mL; Step A3, 4-trifluoromethylphenylacetic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide are added to a reactor containing N,N-dimethylformamide, mixed and stirred for 1.5 hours, the pH is adjusted to 5, and then the intermediate 2 is added, and stirring is continued for 7 hours. After the reaction is completed, the solvent is removed by rotary evaporation, and vacuum dried at 80° C. for 24 hours to obtain a fluorine-containing hyperbranched polymer, and the amount ratio of intermediate 2, p-toluenesulfonic acid, 4-trifluoromethylphenylacetic acid and N,N-dimethylformamide is 0.04 mol: 0.15 g: 0.08 mol: 100 mL.

[0017] Comparative Example 1 This comparative example is commercially available synthetic mica.

[0018] The synthetic mica in Examples 1-3 and Comparative Example 1 was subjected to performance tests, and the test results are shown in Table 1: Table 1 Contact angle (°) Example 1 121±2 Example 2 126±2 Example 3 123±2 Comparative Example 1 70±2 It can be seen from Table 1 that the water contact angle of the synthetic mica prepared by the modified method of the present invention is 120-126°, indicating that it has good hydrophobicity, which is mainly because the surface of the synthetic mica is grafted with terminal fluorocarbon.

[0019] Contact angle test: The modified synthetic mica prepared in Examples 1 to 5 was pressed into a sheet at a pressure of 10 to 12 MPa using a JC2000C1 contact angle measuring instrument produced by Shanghai Zhongchen Digital Technology Equipment Co., Ltd. to measure the contact angle.

[0020] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing hydrophobic synthetic mica, characterized in that: The following steps are involved: Step S1, stirring and mixing synthetic mica and deionized water, then adding ammonium bicarbonate, stirring for 5-10 minutes, vacuum filtering, placing in a drying oven at 150° C. for drying and calcining for 3 hours, then adding 3-aminopropyltrimethylsilane solution, stirring for 30-60 minutes, standing for 1 hour, vacuum filtering, placing at 60° C. for vacuum drying for 6 hours, and obtaining amino-compounded synthetic mica; Step S2, adding the fluorine-containing hyperbranched polymer into a reactor containing deionized water, ultrasonically dispersing for 30 minutes, and cooling to 0°C in an ice-water bath, then sequentially adding 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide into the reactor, mixing and stirring for 1 hour, then adding the amino synthetic mica aqueous solution, stirring for 8-12 hours in an ice-water bath, after the reaction is completed, filtering, washing three times, and vacuum drying at 60°C for 6 hours to obtain hydrophobic synthetic mica.

2. The method for preparing hydrophobic synthetic mica according to claim 1, characterized in that: In step S1, the mass ratio of the synthesized mica, 3-aminopropyltrimethylsilane solution and deionized water is 1:9:

20.

3. The method for preparing hydrophobic synthetic mica according to claim 1, characterized in that: The mass ratio of 3-aminopropyltrimethylsilane, deionized water and methanol in the 3-aminopropyltrimethylsilane solution in step S1 is 1:1:

9.

4. The method for preparing hydrophobic synthetic mica according to claim 1, characterized in that: The mass ratio of the fluorinated hyperbranched polymer, deionized water, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N-hydroxysuccinimide and amino-synthesized mica aqueous solution in step S2 is 5-10 g: 50 g: 0.01-0.05 g: 0.01-0.05 g: 50 g.

5. The method for preparing hydrophobic synthetic mica according to claim 1, characterized in that: The mass ratio of the aminated synthetic mica to deionized water in the aqueous solution of aminated synthetic mica in step S2 is 1:

10.

6. The method for preparing hydrophobic synthetic mica according to claim 1, characterized in that: The fluorine-containing hyperbranched polymer is prepared by the following steps: Step A1, add succinic anhydride to a reactor containing N, N-dimethylacetamide, mix and stir for 30 minutes, then add diisopropanolamine, raise the temperature to 70°C, react for 0.5-1.5 hours, after the reaction is completed, remove the solvent by distillation under reduced pressure, and vacuum dry at 80°C for 12 hours to obtain intermediate 1; Step A2, adding intermediate 1, p-toluenesulfonic acid and toluene into a reactor containing N, N-dimethylformamide, stirring and mixing, slowly dropping glycine N, N-dimethylformamide solution, heating to 140°C and reacting under stirring for 5 hours, after the reaction is completed, standing and cooling the mixture, washing with deionized water, filtering, and drying in a vacuum drying oven at 60°C for 24 hours to obtain intermediate 2; Step A3, add 4-trifluoromethylphenylacetic acid and 1-ethyl-(3-dimethylaminopropyl)carbodiimide to a reactor containing N,N-dimethylformamide, mix and stir for 0.5-1.5h, adjust the pH to 5, then add intermediate 2, continue stirring for 5-7h, after the reaction is completed, remove the solvent by rotary evaporation, and vacuum dry at 80°C for 24h to obtain a fluorinated hyperbranched polymer.

7. The method for preparing hydrophobic synthetic mica according to claim 1, characterized in that: In step A1, the usage ratio of succinic anhydride, diisopropanolamine and N,N-dimethylacetamide is 0.01-0.03 mol: 0.01-0.03 mol: 10 mL.

8. The method for preparing hydrophobic synthetic mica according to claim 1, characterized in that: In step A2, the usage ratio of intermediate 1, p-toluenesulfonic acid and toluene, N,N-dimethylformamide and glycine N,N-dimethylformamide solution is 0.05-0.1 mol: 0.06-0.1 g: 22-25 mL: 20 mL: 40 mL, and the usage ratio of glycine and N,N-dimethylformamide in the glycine N,N-dimethylformamide solution is 0.1-0.2 mol: 40 mL.

9. The method for preparing hydrophobic synthetic mica according to claim 1, characterized in that: In step A3, the usage ratio of intermediate 2, p-toluenesulfonic acid, 4-trifluoromethylphenylacetic acid and N,N-dimethylformamide is 0.025-0.04 mol: 0.08-0.15 g: 0.05-0.08 mol: 100 mL.