Low-cost preparation process of high-strength mica column

Abstract

The invention relates to the technical field of mica piece preparation, in particular to a low-cost preparation process of a high-strength mica column. The invention relates to a low-cost preparation process of a high-strength mica column, which comprises the following steps: preparing mica slurry from 15.0-37.5 parts of organic silica gel with the solid content of 40-60wt%, 0.1-0.5 part of potassium titanate whisker, 0.4-0.6 part of coupling agent, 5-20 parts of hollow glass powder and 65.0-91.5 parts of white mica powder, casting the mica slurry into a forming mold, heating to remove an organic solvent in the mica slurry, and preparing the high-strength mica column at 120-160 DEG C and normal pressure to obtain the high-strength mica column. Carrying out pre-hot press molding for 240-360 seconds under the pressure of 5-20 MPa to obtain a prefabricated mica column, and carrying out hot press molding for 600-900 seconds under the pressure of 30-60 MPa at the temperature of 120-160 DEG C and vacuumizing to obtain a finished product mica column. The mica column provided by the invention has good flame-retardant and heat-insulating properties, insulation and breakdown resistance, and also has good bending strength and impact toughness.

Description

Technical Field

[0001] The present invention relates to the technical field of mica part preparation, and in particular to a low-cost preparation process for high-strength mica columns. Background Art

[0002] Mica columnar materials are mainly made of mica powder and thermosetting resin, which have good electrical insulation, flame retardant safety performance and mechanical strength, can effectively prevent current leakage and short circuit and still work stably at high temperatures, and are widely used in the fields of electronics, electricity, new energy vehicles, transformers, motors, electric furnaces, etc.

[0003] The existing mica columnar materials are made of mica paper and silicone rubber. After the mica paper is bonded and rolled with silicone rubber, it is mechanically rolled and pressed into a rod. The obtained rod is cut and polished after high-temperature baking to obtain the finished mica column material. The content of silicone rubber in flexible mica paper is usually ≥15wt% to ensure its flexibility and facilitate the operation of rolling into columns. And silicone rubber is also used to fill the gaps between the rolled mica papers in the finished mica column material. Usually, the content of silicone rubber in the finished mica column material is 18-24wt%. The relatively high content of silicone rubber makes the mica column material have relatively good toughness, but its electrical insulation and mechanical strength are relatively poor, which limits its application range. Therefore, the inventor provides a low-cost preparation process for high-strength mica columns. Summary of the Invention

[0004] In order to solve the problem that the electrical insulation and mechanical strength of the existing mica columns are relatively poor, the present invention provides a low-cost preparation process for high-strength mica columns.

[0005] The low-cost preparation process for high-strength mica columns provided by the present invention is achieved through the following scheme: A low-cost preparation process for high-strength mica columns includes the following steps: Step 1, prepare mica slurry; The mica slurry formula is made of the following raw materials in parts by weight: 15.0-37.5 parts of silicone rubber with a solid content of 40-60wt%, 0.1-0.5 parts of potassium titanate whiskers, 0.4-0.6 parts of coupling agent, 5-20 parts of hollow glass powder, 65.0-91.5 parts of muscovite powder; Step 2, pour the mica slurry into a molding die, heat to remove the organic solvent in the mica slurry, and pre-press and form at 120-160°C and normal pressure under a pressure of 5-20MPa for 240-360s to obtain a prefabricated mica column; Step 3, the obtained prefabricated mica column is hot-pressed and formed at 120-160°C and under vacuum at a pressure of 30-60MPa for 600-900s to obtain the finished mica column.

[0006] The glue content in the finished mica column is 10-12wt%; the flexural strength of the finished mica column is ≥220MPa; the breakdown strength of the finished mica column is ≥35.0kv / mm.

[0007] The mica column in the present invention has good flame retardant and heat insulation properties, insulation and breakdown resistance properties, and also has good flexural strength and impact toughness. And the preparation process of the present invention is relatively simple, with relatively low requirements for personal operation, relatively low difficulty in industrial production, easy to realize industrial manufacturing, optimize the production cost of the mica column, and thus enhance the overall market competitiveness of the mica column.

[0008] Preferably, the method for preparing the mica slurry in step one is as follows: Dissolve 0.5-2 parts of coupling agent in 400-600 parts of deionized water, add dilute hydrochloric acid to adjust the pH value to 3-4, add 65.0-91.5 parts of muscovite powder, heat up to 40-50°C, mechanically stir at 80-160rpm for 20-40min, filter, wash, and vacuum dry to obtain coupling agent-modified muscovite powder; Mix 65.0-91.5 parts of coupling agent-modified muscovite powder, 15.0-37.5 parts of silicone rubber with a solid content of 40-60wt%, 0.1-0.5 parts of potassium titanate whiskers, 0.4-0.6 parts of coupling agent, and 5-20 parts of hollow glass powder evenly, and evacuate to remove bubbles to obtain the finished mica slurry.

[0009] The preparation method of the finished mica slurry provided in the present invention is relatively simple, which can improve the overall preparation efficiency of the mica column, and thus reduce the overall production cost of the mica column.

[0010] Preferably, the muscovite powder is an aggregate, and the muscovite powder aggregate is composed of 10-25 parts of muscovite powder with a mesh size of 180-250, 10-25 parts of muscovite powder with a mesh size of 250-325, 30-50 parts of muscovite powder with a mesh size of 325-600, 5-15 parts of muscovite powder with a mesh size of 600-1000, 5-10 parts of muscovite powder with a mesh size of 1000-2000, and 5-10 parts of muscovite powder sieved through a 2000-mesh sieve.

[0011] The muscovite powder in the present invention is configured in the form of an aggregate, which can improve the overall density of the mica column, and thus improve the overall mechanical strength and impact toughness of the mica column.

[0012] Preferably, the muscovite powder is an aggregate, and the muscovite powder aggregate is composed of 10 parts of muscovite powder with a mesh size of 180-250, 15 parts of muscovite powder with a mesh size of 250-325, 50 parts of muscovite powder with a mesh size of 325-600, 10 parts of muscovite powder with a mesh size of 600-1000, 10 parts of muscovite powder with a mesh size of 1000-2000, and 5 parts of muscovite powder sieved through a 2000-mesh sieve.

[0013] By adopting the above technical solution, the overall density of the mica column can be further improved, and the overall mechanical strength and impact toughness of the mica column can be enhanced.

[0014] Preferably, the coupling agent is at least one of 3-(3-aminophenoxy)propyltrimethoxysilane, 3-(3-aminophenoxy)propyltriethoxysilane, trimethoxy[3-(phenylamino)propyl]silane, triethoxy[3-(phenylamino)propyl]silane, p-aminophenyltrimethoxysilane, and p-aminophenyltriethoxysilane.

[0015] By adopting the above technical solution, the compatibility between potassium titanate whiskers, hollow glass powder, muscovite powder and silicone resin can be improved, the curing time can be shortened, and the overall mechanical strength and impact toughness of the mica column can be improved.

[0016] Preferably, the potassium titanate whiskers have a diameter of 0.2 - 5 microns and an aspect ratio of 10 - 50.

[0017] In the present invention, potassium titanate whiskers with a high aspect ratio are preferably used, which can improve the overall mechanical strength and impact toughness of the mica column. Preferably, the potassium titanate whiskers are composed of potassium titanate whiskers with a diameter of 0.2 - 1 micron and an aspect ratio of 30 - 50, and potassium titanate whiskers with a diameter of 3 - 5 microns and an aspect ratio of 10 - 20.

[0018] Preferably, the mica slurry formulation further includes tetrapod-shaped zinc oxide whiskers, and the tetrapod-shaped zinc oxide whiskers have a diameter of 0.5 - 5 microns and a length of 10 - 50 microns.

[0019] In the present invention, the addition of tetrapod-shaped zinc oxide whiskers can, on the one hand, improve the overall mechanical strength and impact toughness of the mica column, and on the other hand, improve the antibacterial and mildew-proof properties of the mica column, expanding its application range. It should be noted that the tetrapod-shaped zinc oxide whiskers will affect the overall breakdown resistance of the mica column. The addition amount of the tetrapod-shaped zinc oxide whiskers is preferably controlled at 0.05 - 0.20 parts to ensure the overall breakdown resistance of the mica column while improving the mechanical strength, impact toughness and antibacterial and mildew-proof properties.

[0020] Preferably, the isostatic strength of the hollow glass powder is 120 - 170 MPa, the true density is 0.58 - 1.30 g / cm 3 , the particle size distribution is 2 - 130 um, and the average particle size D50 is 15 - 30 microns.

[0021] By adopting the above technical solution, while ensuring the overall breakdown resistance of the mica column, the mechanical strength is improved, the overall density of the mica column is reduced, the purpose of lightweight reduction of the mica column is achieved, and its application range is expanded.

[0022] Preferred preparation scheme, a low-cost preparation process for high-strength mica columns, includes the following steps: Step 1, configure mica slurry; The mica slurry is made from the following raw materials by weight: 24 parts of organosilica gel with a solid content of 50wt%, 0.3 parts of potassium titanate whiskers, 0.1 part of tetrapod zinc oxide whiskers, 0.5 part of 3-(3-aminophenoxy)propyltrimethoxysilane, 10 - 12 parts of hollow glass powder C100, and 70 - 80 parts of muscovite powder; Step 2, pour the mica slurry into a molding die, heat to remove the organic solvent in the mica slurry, and pre-press and form at 120 - 125°C and normal pressure under a pressure of 5 - 20 MPa for 280 - 300 s to obtain a prefabricated mica column; Step 3, heat-press the obtained prefabricated mica column at 155 - 160°C under vacuum at a pressure of 30 - 60 MPa for 800 - 900 s to obtain a finished mica column.

[0023] In summary, the present application has the following advantages: 1. The mica column in the present invention has good flame retardant and heat insulation properties, insulation and breakdown resistance properties, and also has good bending strength and impact toughness.

[0024] 2. The preparation process of the present invention is relatively simple, has relatively low requirements for personal operation, has relatively low difficulty in industrial production, is easy to realize industrial manufacturing, and reduces the production cost of mica columns. Specific Embodiments

[0025] In order to further understand the creativity and technological progress of the present invention, the preferred implementation schemes of the present invention are described in detail below in combination with examples and comparative examples. Examples

[0026] A formula for a high-strength mica column is made from the following raw materials by weight: 15.0 - 37.5 parts of organosilica gel with a solid content of 40 - 60wt%, 0.1 - 0.5 parts of potassium titanate whiskers, 0.4 - 0.6 parts of coupling agent, 5 - 20 parts of hollow glass powder, and 65.0 - 91.5 parts of muscovite powder.

[0027] The muscovite powder is an aggregate, and the muscovite powder aggregate is composed of 10 - 25 parts of muscovite powder with a mesh size of 180 - 250, 10 - 25 parts of muscovite powder with a mesh size of 250 - 325, 30 - 50 parts of muscovite powder with a mesh size of 325 - 600, 5 - 15 parts of muscovite powder with a mesh size of 600 - 1000, 5 - 10 parts of muscovite powder with a mesh size of 1000 - 2000, and 5 - 10 parts of muscovite powder sieved through a 2000 - mesh sieve.

[0028] Preferably, muscovite powder is used as the aggregate. The muscovite powder aggregate is composed of 10 parts of muscovite powder with a mesh size of 180 - 250, 15 parts of muscovite powder with a mesh size of 250 - 325, 50 parts of muscovite powder with a mesh size of 325 - 600, 10 parts of muscovite powder with a mesh size of 600 - 1000, 10 parts of muscovite powder with a mesh size of 1000 - 2000, and 5 parts of muscovite powder sieved through a 2000 - mesh sieve.

[0029] The muscovite powder needs to be surface - modified to improve its compatibility with the silicone rubber.

[0030] The surface - modification method of the muscovite powder is as follows: Dissolve 0.5 - 2.0 parts of coupling agent in 400 - 600 parts of deionized water, add dilute hydrochloric acid to adjust the pH value to 3 - 4, add 65.0 - 91.5 parts of muscovite powder, heat up to 40 - 50 °C, mechanically stir at 80 - 160 rpm for 20 - 40 min, filter, wash, and vacuum - dry to obtain the coupling - agent - modified muscovite powder.

[0031] The coupling agent is at least one of 3 - (3 - aminophenoxy)propyltrimethoxysilane, 3 - (3 - aminophenoxy)propyltriethoxysilane, trimethoxy[3 - (phenylamino)propyl]silane, triethoxy[3 - (phenylamino)propyl]silane, p - aminophenyltrimethoxysilane, and p - aminophenyltriethoxysilane.

[0032] The diameter of the potassium titanate whisker is 0.2 - 5 microns, and the aspect ratio is 10 - 50.

[0033] The isostatic strength of the hollow glass powder is 120 - 170 MPa, the true density is 0.58 - 1.30 g / cm 3 , the particle size distribution is 2 - 130 μm, and the average particle size D50 is 15 - 30 microns.

[0034] In order to improve the antibacterial and antifungal properties of the mica column and also assist in enhancing the mechanical properties of the mica column, the mica slurry formula also includes tetrapod - shaped zinc oxide whiskers. The diameter of the tetrapod - shaped zinc oxide whiskers is 0.5 - 5 microns, and the length is 10 - 50 microns.

[0035] A preparation method for a high - strength mica column with low cost, comprising the following steps: Step 1, prepare the mica slurry: Mix 65 - 91.5 parts of the coupling - agent - modified muscovite powder, 15.0 - 37.5 parts of silicone rubber with a solid content of 40 - 60 wt%, 0.1 - 0.5 parts of potassium titanate whiskers, 0.4 - 0.6 parts of coupling agent, and 5 - 20 parts of hollow glass powder evenly, and perform vacuum defoaming treatment to obtain the finished mica slurry. Step 2: Cast the mica slurry into a molding mold, heat to remove the organic solvent in the mica slurry, and preheat and press at 120-160° C. and normal pressure for 240-360 seconds at a pressure of 5-20 MPa to obtain a prefabricated mica column; Step 3: The obtained prefabricated mica column is hot-pressed at 120-160°C and vacuumed at a pressure of 30-60MPa for 600-900s to obtain a finished mica column. The finished mica column has a rubber content of 10-12wt%, a bending strength of ≥220MPa, a puncture resistance of ≥35.0kv / mm, and a thermal conductivity of ≤0.10W / (m·K).

[0036] Example 1: A formula of a high-strength mica column is as follows: 16 parts of 50wt% solid content organic silica gel-KR-242A silicone resin, 0.2 parts of potassium titanate whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, and 83.3 parts of 325-600 mesh muscovite powder.

[0037] Potassium titanate whiskers have a diameter of 0.2-0.5 microns and a length of 5-15 microns, provided by Nantong Aoxin Electronic Technology Co., Ltd. The organic silica gel is KR-242A silicone resin, brand: Shin-Etsu of Japan. The coupling agent is 3-(3-aminophenoxy)propyltrimethoxysilane, CAS: 55648-29-8, Beijing Bailingwei Technology Co., Ltd. Hollow glass powder C100, isostatic strength is 165.52MPa, true density is 0.0.9-1.30g / cm 3 , particle size distribution is 2-130um, average particle size D50 is 15 microns, Zhongke Huaxing New Materials Co., Ltd. 325-600 mesh muscovite powder, Lingshou County Shuochuan Mineral Products Processing Plant.

[0038] A method for preparing a high-strength mica column with a low-cost preparation process comprises the following steps: Step 1: Prepare mica slurry: S1.1, add 8g of coupling agent-3-(3-aminophenoxy)propyltrimethoxysilane and 5kg of deionized water into a reactor and mix well, add 0.1M dilute hydrochloric acid to adjust the pH value to 3.5, add 833g of 325-600 mesh muscovite powder, heat to 40°C in a water bath, stir mechanically at 120rpm for 30min, filter with a 600-mesh sieve, wash the filtered product with deionized water until neutral, and vacuum dry at 120°C for 2h to obtain coupling agent-modified muscovite powder; S1.2. Place 833 g of coupling agent - modified muscovite powder, 200 g of KR - 242A silicone resin, 2 g of potassium titanate whiskers, 5 g of 3 - (3 - aminophenoxy) propyltrimethoxysilane, and 80 g of hollow glass powder C100 into a reaction kettle, mix at 120 rpm for 15 min until evenly mixed, maintain the rotation speed of 120 rpm, conduct vacuum defoaming treatment for 15 min, then introduce nitrogen to restore normal pressure to obtain the finished mica slurry; Step 2. Pour the mica slurry into a column - shaped molding mold, install a high - frequency vibrating rod on the column - shaped molding mold. The frequency of the high - frequency vibrating rod is 12,000 times per minute. Heat to 112 °C to remove isopropyl alcohol and toluene in the mica slurry. At 125 °C and normal pressure, pre - press and form at a pressure of 10 MPa for 300 s to obtain a pre - formed mica column; Step 3. Subject the obtained pre - formed mica column to hot pressing at 160 °C and under vacuum at a pressure of 40 MPa for 900 s. After hot pressing is completed, cool to room temperature, demold and polish to obtain the finished mica column.

[0039] The difference between Example 2 and Example 1 is that the formula of the high - strength mica column is as follows: 20 parts of KR - 242A silicone resin, 0.2 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, and 81.3 parts of 325 - 600 - mesh muscovite powder.

[0040] The difference between Example 3 and Example 1 is that the formula of the high - strength mica column is as follows: 24 parts of KR - 242A silicone resin, 0.2 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, and 79.3 parts of 325 - 600 - mesh muscovite powder.

[0041] The difference between Example 4 and Example 1 is that the formula of the high - strength mica column is as follows: 29 parts of KR - 242A silicone resin, 0.2 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, and 77.3 parts of 325 - 600 - mesh muscovite powder.

[0042] The difference between Comparative Example 1 and Example 1 is that potassium titanate whiskers and hollow glass powder C100 are not added to the formula of the high - strength mica column. The specific formula is as follows: 16 parts of KR - 242A silicone resin, 0.5 part of coupling agent, and 91.5 parts of 325 - 600 - mesh muscovite powder.

[0043] The difference between Comparative Example 2 and Example 1 is that potassium titanate whiskers are not added to the formula of the high - strength mica column. The specific formula is as follows: 16 parts of KR - 242A silicone resin, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, and 83.5 parts of 325 - 600 - mesh muscovite powder.

[0044] The difference between Comparative Example 3 and Example 1 lies in that the formulation of the high-strength mica column is as follows: 32 parts of KR-242A silicone resin, 0.2 parts of potassium titanate whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, and 75.3 parts of muscovite powder with a particle size of 325-600 mesh.

[0045] Performance detection test: 1. The flexural strength was determined according to the test method for mica products GB / T5019.2-2009, Article 11 "Flexural strength and flexural modulus of elasticity". The test span was 16 mm, the test speed was 50 mm / min, and the radius of the indenter was 5 mm.

[0046] 2. The electrical strength was tested according to the test method for mica products GB / T5019.2-2009, Article 22 "Electrical strength". A Φ25mm / Φ75mm cylindrical electrode system was used, the voltage rise rate was 0.5 kV / s, and the test was carried out in 25# transformer oil at 23.0°C ± 2.0°C.

[0047] 3. The density was tested according to the test method for mica products GB / T5019.2-2009, Article 6 "Density".

[0048] 4. The glue content was tested according to Article 8.4.5 of GB / T5019.2-2009 "Materials without reinforcement of organosilicon adhesives (insoluble adhesives)".

[0049] 5. The thermal conductivity was determined with reference to GB / T 10297-1998 "Test method for thermal conductivity of non-metallic solid materials - Hot wire method".

[0050] Table 1 shows the performance test parameters of the mica columns in Examples 1-4 and Comparative Examples 1-3

[0051] Combining Example 1 and Comparative Examples 1-2 and referring to Table 1, it can be seen that the addition of potassium titanate whiskers can improve the mechanical strength of the mica column and has little effect on the electrical strength of the mica column. That is, on the premise of ensuring the electrical insulation performance of the mica column, the addition of potassium titanate whiskers improves the overall mechanical strength of the mica column.

[0052] Combining Examples 1-4 and Comparative Example 3 and referring to Table 1, it can be seen that it is appropriate to control the glue content in the mica column to 8-14 wt%, which can ensure the mechanical strength and electrical insulation performance of the mica column. If the glue content in the mica column is too high, the overall electrical strength of the mica column will be low, but the density of the mica column will also decrease. If the mica column has a lightweight requirement, the glue content in the mica column can be selected to be 10-12 wt%, and the comprehensive performance of the mica column is relatively good.

[0053] Select Example 3 as the basic formula of the mica column, explore the influence of the addition amount of potassium titanate whiskers on the performance of the mica column, select the most suitable mica column formula for industrial production, and reduce the overall production cost.

[0054] The difference between Example 5 and Example 3 is that the formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.1 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, 79.4 parts of muscovite powder with a mesh size of 325-600.

[0055] The difference between Example 6 and Example 3 is that the formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, 79.2 parts of muscovite powder with a mesh size of 325-600.

[0056] The difference between Example 7 and Example 3 is that the formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.4 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, 79 parts of muscovite powder with a mesh size of 325-600.

[0057] The difference between Example 8 and Example 3 is that the formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.5 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, 79 parts of muscovite powder with a mesh size of 325-600.

[0058] The difference between Example 9 and Example 3 is that the formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, 79.2 parts of muscovite powder with a mesh size of 325-600. The diameter of the potassium titanate whiskers is 2-5 microns and the length is 20-50 microns, customized from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0059] The difference between Example 10 and Example 3 is that the formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.1 part of potassium titanate whisker A, 0.2 part of potassium titanate whisker B, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, 79.2 parts of muscovite powder with a mesh size of 325-600.

[0060] The diameter of potassium titanate whisker A is 0.2-0.5 microns and the length is 5-15 microns, provided by Nantong Aoxin Electronic Technology Co., Ltd. The diameter of potassium titanate whisker B is 2-5 microns and the length is 20-50 microns, customized from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.

[0061] The difference between Comparative Example 4 and Example 3 is as follows: The formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.05 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, and 79.45 parts of muscovite powder with a mesh size of 325-600.

[0062] The difference between Comparative Example 5 and Example 3 is as follows: The formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.6 part of potassium titanate whiskers, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, and 78.9 parts of muscovite powder with a mesh size of 325-600.

[0063] The difference between Control Group 1 and Example 3 is as follows: The formula of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.5 part of coupling agent, 8 parts of hollow glass powder C100, and 79.5 parts of muscovite powder with a mesh size of 325-600.

[0064] Table 2: Performance test parameter table of mica columns in Examples 3, 5-110 and Comparative Examples 4-5

[0065] Combining Examples 3, 5-8 and Comparative Examples 4-5 and Table 2, it can be seen that the addition amount of potassium titanate whiskers is preferably controlled at 0.1-0.5 parts. When the addition amount of potassium titanate whiskers is too low, the improvement of the mechanical properties of the mica column is not obvious; while when the addition amount of potassium titanate whiskers is too high, the improvement amplitude of the mechanical properties of the mica column slows down, the production cost of the mica column increases, which is not conducive to the mass production of mica columns.

[0066] Combining Example 6 and Examples 9-10 and Table 2, it can be seen that the diameter and aspect ratio of potassium titanate whiskers have an impact on the mechanical properties of mica columns. Selecting potassium titanate whiskers with a high aspect ratio has a relatively better strengthening effect on the mechanical properties of mica columns. Using two different specifications of potassium titanate whiskers in Example 10, the prepared mica column has better denseness and better optimization of its mechanical properties. On the premise of ensuring similar mechanical properties of mica columns, the addition amount of potassium titanate whiskers obtained by mixing two different specifications of potassium titanate whiskers is relatively less, which can reduce the overall production cost of mica columns.

[0067] The application scenarios of mica columns include humid and hot climate environments, where harmful microorganisms such as bacteria and molds are likely to grow. In order to expand the application range of mica columns, an appropriate amount of tetrapod zinc oxide whiskers is added to the mica column formula.

[0068] Example 11 is different from Example 6 in that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.02 parts of tetrapod zinc oxide whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, and 79.18 parts of muscovite powder with a particle size of 325-600 mesh.

[0069] Example 12 is different from Example 6 in that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.05 parts of tetrapod zinc oxide whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, and 79.15 parts of muscovite powder with a particle size of 325-600 mesh. The tetrapod zinc oxide whiskers are of the SS-ZJ52 type and are provided by Hangzhou Jikang New Materials Co., Ltd.

[0070] Example 13 is different from Example 6 in that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.10 parts of tetrapod zinc oxide whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, and 79.1 parts of muscovite powder with a particle size of 325-600 mesh.

[0071] Example 14 is different from Example 6 in that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.15 parts of tetrapod zinc oxide whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, and 79.05 parts of muscovite powder with a particle size of 325-600 mesh.

[0072] Example 15 is different from Example 6 in that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.20 parts of tetrapod zinc oxide whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, and 79 parts of muscovite powder with a particle size of 325-600 mesh.

[0073] Example 16 is different from Example 6 in that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.3 parts of tetrapod zinc oxide whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, and 78.9 parts of muscovite powder with a particle size of 325-600 mesh.

[0074] Table 3: Performance test parameter table of mica columns in Example 6 and Examples 11-16

[0075] Combined with Example 6 and Examples 11 - 15 and in conjunction with Table 3, it can be seen that the addition amount of tetrapod zinc oxide whiskers is preferably controlled at 0.5 - 0.2 parts, which can ensure the electrical insulation of the mica column while improving the mechanical properties of the mica column, and the presence of tetrapod zinc oxide whiskers can improve the hygienic safety of the mica column.

[0076] The difference between Example 17 and Example 13 is that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.10 parts of tetrapod zinc oxide whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, 79.1 parts of muscovite powder aggregate. The muscovite powder aggregate consists of 10 parts of muscovite powder with a mesh size of 180 - 250, 15 parts of muscovite powder with a mesh size of 250 - 325, 50 parts of muscovite powder with a mesh size of 325 - 600, 10 parts of muscovite powder with a mesh size of 600 - 1000, 10 parts of muscovite powder with a mesh size of 1000 - 2000, and 5 parts of muscovite powder sifted through a 2000-mesh sieve.

[0077] The difference between Example 18 and Example 17 is that the muscovite powder aggregate consists of 10 parts of muscovite powder with a mesh size of 180 - 250, 20 parts of muscovite powder with a mesh size of 250 - 325, 40 parts of muscovite powder with a mesh size of 325 - 600, 10 parts of muscovite powder with a mesh size of 600 - 1000, 10 parts of muscovite powder with a mesh size of 1000 - 2000, and 10 parts of muscovite powder sifted through a 2000-mesh sieve.

[0078] The difference between Example 19 and Example 17 is that the muscovite powder aggregate consists of 10 parts of muscovite powder with a mesh size of 180 - 250, 10 parts of muscovite powder with a mesh size of 250 - 325, 55 parts of muscovite powder with a mesh size of 325 - 600, 10 parts of muscovite powder with a mesh size of 600 - 1000, 10 parts of muscovite powder with a mesh size of 1000 - 2000, and 5 parts of muscovite powder sifted through a 2000-mesh sieve.

[0079] The difference between Comparative Example 6 and Example 13 is that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.10 parts of tetrapod zinc oxide whiskers, 0.5 parts of coupling agent, 8 parts of hollow glass powder C100, 79.1 parts of muscovite powder with a mesh size of 180 - 250.

[0080] The difference between Comparative Example 7 and Example 13 is that the muscovite powder with a mesh size of 325 - 600 in the formulation of the high-strength mica column is replaced with phlogopite powder with a mesh size of 325 - 600.

[0081] Table 4: Performance test parameter table of mica columns in Example 13, Examples 17 - 19 and Comparative Examples 6 - 7

[0082] Combined with Example 13, Examples 17 - 19 and Comparative Example 7 and Table 4, it can be seen that the mica columns prepared with muscovite powder having a particle size controlled to 325 - 600 mesh have better electrical insulation and mechanical properties.

[0083] Combined with Example 13, Examples 17 - 19 and Comparative Example 7 and Table 4, it can be seen that the mica columns prepared with phlogopite powder have relatively better mechanical properties, but their electrical insulation is relatively poor. In high - frequency and high - voltage application scenarios such as transformers and motors, it is better to choose muscovite as the basic mica filler.

[0084] Combined with Example 13, Examples 17 - 19 and Comparative Example 7 and Table 4, it can be seen that the mica columns prepared with muscovite powder aggregate have better electrical insulation and mechanical properties than those prepared with muscovite powder of a single particle size. It can improve the density of the prepared mica columns, reduce the internal defects of the mica columns, and improve the overall comprehensive performance.

[0085] The difference between Example 20 and Example 17 is that the formula of the high - strength mica column is as follows: 24 parts of KR - 242A silicone resin, 0.3 part of potassium titanate whiskers, 0.10 part of tetrapod - shaped zinc oxide whiskers, 0.5 part of coupling agent, 0 part of hollow glass powder C100, 87.1 parts of muscovite powder aggregate.

[0086] The difference between Example 21 and Example 17 is that the formula of the high - strength mica column is as follows: 24 parts of KR - 242A silicone resin, 0.3 part of potassium titanate whiskers, 0.10 part of tetrapod - shaped zinc oxide whiskers, 0.5 part of coupling agent, 4 parts of hollow glass powder C100, 83.1 parts of muscovite powder aggregate. The difference between Example 22 and Example 17 is that the formula of the high - strength mica column is as follows: 24 parts of KR - 242A silicone resin, 0.3 part of potassium titanate whiskers, 0.10 part of tetrapod - shaped zinc oxide whiskers, 0.5 part of coupling agent, 12 parts of hollow glass powder C100, 75.1 parts of muscovite powder aggregate.

[0087] The difference between Example 23 and Example 17 is that the formula of the high - strength mica column is as follows: 24 parts of KR - 242A silicone resin, 0.3 part of potassium titanate whiskers, 0.10 part of tetrapod - shaped zinc oxide whiskers, 0.5 part of coupling agent, 16 parts of hollow glass powder C100, 71.1 parts of muscovite powder aggregate.

[0088] The difference between Example 24 and Example 17 is that the formula of the high - strength mica column is as follows: 24 parts of KR - 242A silicone resin, 0.3 part of potassium titanate whiskers, 0.10 part of tetrapod - shaped zinc oxide whiskers, 0.5 part of coupling agent, 20 parts of hollow glass powder C100, 67.1 parts of muscovite powder aggregate.

[0089] The difference between Comparative Example 8 and Example 17 lies in that the formulation of the high-strength mica column is as follows: 24 parts of KR-242A silicone resin, 0.3 parts of potassium titanate whiskers, 0.10 parts of tetrapod-shaped zinc oxide whiskers, 0.5 parts of coupling agent, 24 parts of hollow glass powder C100, and 63.1 parts of muscovite powder aggregate.

[0090] Table 5: Performance test parameter table of mica columns in Example 17, Examples 20-24, and Comparative Example 8

[0091] Combining Example 17, Examples 20-24, and Comparative Example 8 and referring to Table 5, it can be seen that the addition of hollow glass powder C100 can improve the heat insulation performance of the mica column, but the addition of hollow glass powder C100 causes a decrease in the flexural strength of the mica column. It is advisable to control the addition amount of hollow glass powder C100 to 8-12 parts.

[0092] It should be noted that: This specific embodiment is only an explanatory illustration of the technical solution of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A low-cost preparation process for high-strength mica columns, characterized in that: The following steps are involved: Step 1, preparing mica slurry; The mica slurry formula comprises the following raw materials in parts by weight: 15.0-37.5 parts of organic silica gel with a solid content of 40-60wt%, 0.1-0.5 parts of potassium titanate whiskers, 0.4-0.6 parts of coupling agent, 5-20 parts of hollow glass powder, and 65.0-91.5 parts of muscovite powder; Step 2: Cast the mica slurry into a molding mold, heat to remove the organic solvent in the mica slurry, and preheat and press at 120-160° C. and normal pressure for 240-360 seconds at a pressure of 5-20 MPa to obtain a prefabricated mica column; Step 3: The obtained prefabricated mica column is hot-pressed at 120-160° C. and vacuumed at a pressure of 30-60 MPa for 600-900 seconds to obtain a finished mica column.

2. A low-cost preparation process for high-strength mica columns according to claim 1, characterized in that: The glue content in the finished mica column is 10-12wt%; the bending strength of the finished mica column is ≥220MPa; and the puncture resistance of the finished mica column is ≥35.0kv / mm.

3. The low-cost preparation process of high-strength mica columns according to claim 1, characterized in that: The mica slurry in step 1 is prepared as follows: 0.5-2.0 parts of a coupling agent are dissolved in 400-600 parts of deionized water, dilute hydrochloric acid is added to adjust the pH value to 3-4, 65.0-91.5 parts of white mica powder are added, the temperature is raised to 40-50° C., mechanically stirred at 80-160 rpm for 20-40 min, filtered, washed, and vacuum dried to obtain white mica powder modified by the coupling agent; 65.0-91.5 parts of white mica powder modified by the coupling agent, 15.0-37.5 parts of organic silica gel with a solid content of 40-60wt%, 0.1-0.5 parts of potassium titanate whiskers, 0.4-0.6 parts of a coupling agent, and 5-20 parts of hollow glass powder are mixed evenly, and vacuum defoaming treatment is performed to obtain a finished mica slurry.

4. The low-cost preparation process of high-strength mica columns according to claim 1, characterized in that: The muscovite powder is an aggregate, and the muscovite powder aggregate is composed of 10-25 parts of 180-250 mesh muscovite powder, 10-25 parts of 250-325 mesh muscovite powder, 30-50 parts of 325-600 mesh muscovite powder, 5-15 parts of 600-1000 mesh muscovite powder, 5-10 parts of 1000-2000 mesh muscovite powder, and 5-10 parts of 2000 mesh sieved muscovite powder.

5. A low-cost preparation process for high-strength mica columns according to claim 4, characterized in that: The muscovite powder is an aggregate, and the muscovite powder aggregate is composed of 10 parts of 180-250 mesh muscovite powder, 15 parts of 250-325 mesh muscovite powder, 50 parts of 325-600 mesh muscovite powder, 10 parts of 600-1000 mesh muscovite powder, 10 parts of 1000-2000 mesh muscovite powder, and 5 parts of 2000 mesh sieved muscovite powder.

6. The low-cost preparation process of high-strength mica columns according to claim 1, characterized in that: The coupling agent is at least one of 3-(3-aminophenoxy)propyltrimethoxysilane, 3-(3-aminophenoxy)propyltriethoxysilane, trimethoxy[3-(phenylamino)propyl]silane, triethoxy[3-(phenylamino)propyl]silane, p-aminophenyltrimethoxysilane and p-aminophenyltriethoxysilane.

7. The low-cost preparation process of high-strength mica columns according to claim 1, characterized in that: The potassium titanate whisker has a diameter of 0.2-5 microns and an aspect ratio of 10-50.

8. The low-cost preparation process of high-strength mica columns according to claim 1, characterized in that: The mica slurry formula also includes four-needle zinc oxide whiskers, and the diameter of the four-needle zinc oxide whiskers is 0.5-5 microns and the length is 10-50 microns.

9. A low-cost preparation process for high-strength mica columns according to claim 1, characterized in that: The isostatic pressure strength of the hollow glass powder is 120-170 MPa, and the true density is 0.58-1.30 g / cm 3 , particle size distribution is 2-130um, and the average particle size D50 is 15-30 microns.

10. The low-cost preparation process of high-strength mica columns according to claim 1, characterized in that: The following steps are involved: Step 1, preparing mica slurry; The mica slurry is made of the following raw materials in parts by weight: 24 parts of organic silica gel with a solid content of 50wt%, 0.3 parts of potassium titanate whiskers, 0.1 parts of tetrapod-shaped zinc oxide whiskers, 0.5 parts of 3-(3-aminophenoxy)propyltrimethoxysilane, 10-12 parts of hollow glass powder C100, and 70-80 parts of muscovite powder; Step 2: Cast the mica slurry into a molding mold, heat to remove the organic solvent in the mica slurry, and preheat and press mold at 120-125° C. and normal pressure at a pressure of 5-20 MPa for 280-300 seconds to obtain a prefabricated mica column; Step 3: The obtained prefabricated mica column is hot pressed at 155-160° C. and vacuum at a pressure of 30-60 MPa for 800-900 seconds to obtain a finished mica column.

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