Insulating glass finish paint for electrical equipment and preparation method of insulating glass finish paint

Abstract

The invention relates to the technical field of coatings, and discloses an insulating glass finish paint for electrical equipment and a preparation method of the insulating glass finish paint. The finish paint comprises epoxy resin, a solvent, alumina powder, a modified dispersant, a leveling agent, a defoaming agent and a curing agent in a mass ratio of 100: (40-55): (30-60): (3-8): (0.4-1): (0.6-1.5): (3.6-4.5), the modified dispersant contains a large amount of carboxyl groups, can realize surface modification of alumina powder, reduces agglomeration of alumina, is uniformly dispersed in epoxy resin finish paint, improves the volume resistivity and insulating property of epoxy resin, and has good wear resistance. The modified dispersant contains an imidazole group, can participate in the curing reaction of the epoxy resin, has a good toughening effect on the epoxy resin, and improves the impact strength and toughness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint, in particular to an insulating glass finish for electrical equipment and a preparation method thereof. BACKGROUND

[0002] With the continuous progress of science and technology, glass is increasingly widely used in electrical equipment and electronic components. However, the traditional glass paint has poor insulation, which can easily cause current leakage and other problems, and brings certain hidden dangers to the safe operation of electrical equipment and electronic components. Developing high-performance insulating paint is a research hotspot. Epoxy resin itself has good insulating properties, high mechanical strength, and excellent corrosion resistance, but the toughness and impact resistance of epoxy resin are low, and the wear resistance is not good, which is not conducive to the protection of glass. The research and development of insulating glass finish is still a field full of challenges and opportunities, and it is an urgent need to develop a new type of insulating glass finish to replace traditional paint to prevent current leakage and promote the continuous innovation and development of insulating paint technology.

[0003] Alumina has strong wear resistance, high resistivity, and high mechanical strength, and is widely used in wear-resistant insulating materials, but alumina is prone to agglomeration and has poor dispersibility in epoxy resin, which is not conducive to improving the wear resistance, insulation and other properties of epoxy resin, and will affect the impact strength and other mechanical properties of epoxy resin paint. SUMMARY

[0004] In view of the shortcomings of the prior art, the present application provides an insulating glass finish for electrical equipment and a preparation method thereof, which solves the problem of poor wear resistance and other properties of epoxy resin paint and improves the wear resistance and other properties.

[0005] Technical scheme: An insulating glass finish for electrical equipment, the finish comprises epoxy resin, solvent, alumina powder, modified dispersant, leveling agent, defoaming agent and curing agent in a mass ratio of 100:(40-55):(30-60):(3-8):(0.4-1):(0.6-1.5):(3.6-4.5).

[0006] The preparation method of the finish is as follows: (1) adding dichloromethane, N-Boc-histidine, dibromoalkane and potassium carbonate into a reaction bottle provided with a condensation reflux tube, stirring and reacting, then adding trifluoroacetic acid to the filtrate after filtration, continuing to react, removing the Boc group, distilling under reduced pressure, washing the crude product with petroleum ether, then adding to ethanol, heating and evaporating, cooling and crystallizing, and recrystallizing to obtain dihistidine-based alkane; the reaction formula is as follows: .

[0007] (2) adding ethanol, di-histidine-based alkane, and aqueous solution of glutaraldehyde into a reaction bottle with a condensing reflux tube, drying to remove ethanol and water after reaction, washing the product with ethanol, and drying to obtain a modified dispersant. The reaction formula is: .

[0008] (3) adding solvent, alumina powder, and modified dispersant into a high-speed disperser, shearing and dispersing, then adding epoxy resin, leveling agent, and defoaming agent, shearing and dispersing, and then adding a curing agent to obtain an insulating glass topcoat for electrical equipment.

[0009] Preferably, the solvent includes isopropyl alcohol or n-butanol.

[0010] Preferably, the curing agent is an amine curing agent, including 2-ethyl-4-methylimidazole and 2-methylimidazole.

[0011] Preferably, the molar ratio of N-Boc-histidine, dibromoalkane, and potassium carbonate in (1) is (2-2.4):1:(2.6-3.2).

[0012] Preferably, the structure of the dibromoalkane in (1) is Br-(CH2) n -Br, and n is 10-18.

[0013] Preferably, the temperature during stirring and reaction in (1) is 40-50°C, and the reaction time is 7-10h, and the reaction is refluxed.

[0014] Preferably, the temperature during continued reaction in (1) is 20-30°C, and the reaction time is 3-5h.

[0015] Preferably, the molar ratio of di-histidine-based alkane and glutaraldehyde in (2) is 1:(0.92-1).

[0016] Preferably, the reaction temperature in (2) is 55-70°C, and the reaction time is 12-18h.

[0017] Preferably, the first shearing and dispersing time in (3) is 3-6h, and the temperature is 40-70°C.

[0018] Preferably, the second shearing and dispersing time in (3) is 20-40min, and the temperature is 20-30°C.

[0019] The beneficial technical effects of this invention are as follows: A modified dispersant is obtained by reacting dihistidine-based alkanes with glutaraldehyde via Schiff base polymerization. This dispersant, along with alumina and imidazole curing agents, is then added to epoxy resin to obtain an insulating glass topcoat for electrical equipment. The modified dispersant contains a large number of carboxyl groups, which can modify the surface of alumina powder. The long-chain alkanes and polymer molecular chains it contains can exert a steric hindrance effect, thereby reducing alumina agglomeration and ensuring uniform dispersion in the epoxy resin topcoat, forming an insulating network. This improves the volume resistivity and insulation performance of the epoxy resin, and also enhances its wear resistance.

[0020] The modified dispersant of this invention contains imidazole groups, which can participate in the curing reaction of epoxy resin, thereby chemically bonding the polymer molecular chains containing flexible alkyl groups into the epoxy resin, providing a good toughening effect on the epoxy resin, while improving the interfacial properties between alumina and epoxy resin, improving the compatibility between alumina and epoxy resin, thereby improving the impact strength and toughness of epoxy resin, and better protecting the glass substrate. Attached Figure Description

[0021] Figure 1 The infrared spectrum is that of the modified dispersant prepared in Example 1. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] Example 1 (1) Add 200 mL of dichloromethane, 0.2 mol of N-Boc-histidine (CAS No. 17791-52-5), 0.1 mol of 1,12-dibromododecane, and 0.32 mol of potassium carbonate to a reaction flask equipped with a reflux condenser. Stir the reaction at 40 °C for 10 h. After filtration, add 90 mL of trifluoroacetic acid to the filtrate and react at 30 °C for 3 h. Distill under reduced pressure. Wash the crude product with petroleum ether, then add it to ethanol, heat to evaporate, and cool to crystallize, obtaining dihistidine-based alkanes with the following structural formula: .

[0024] (2) Add 0.8L of ethanol, 0.1mol of dihistidine-based alkane and 10mL of aqueous solution containing 0.1mol of glutaraldehyde to a reaction flask equipped with a reflux condenser. Heat to 60℃ and react for 18h. Dry to remove ethanol and water, wash the product with ethanol, and dry to obtain the modified dispersant. Figure 1 The infrared spectrum shows that 3376 cm⁻¹ -1 The absorption peak is at 1721 cm⁻¹, corresponding to the carboxyl group -OH. -1is the absorption peak of carboxyl C=O, 2963-2832 cm -1 is the characteristic peak of alkyl long chain methylene, 1644 cm -1 is the absorption peak of Schiff base C=N bond, 1602 cm -1 is the characteristic peak of C=N bond in imidazole ring.

[0025] (3) Add 500 g of isopropyl alcohol, 300 g of alumina powder, and 30 g of modified dispersant into a high-speed disperser, disperse at 50°C for 3 h, add 1 kg of epoxy resin E44, 8 g of leveling agent (model BYK306, same below), and 6 g of defoaming agent (model Yilian Chemical 2608, same below), disperse at 20°C for 40 min, and then add 45 g of 2-ethyl-4-methylimidazole to obtain an insulating glass finish for electrical equipment.

[0026] Example 2 (1) Add 300 mL of dichloromethane, 0.24 mol of N-Boc-histidine (CAS No. 17791-52-5), 0.1 mol of 1,10-dibromodecane, and 0.26 mol of potassium carbonate into a reaction bottle equipped with a condenser reflux tube, stir at 50°C for 7 h, filter, add 80 mL of trifluoroacetic acid to the filtrate, react at 20°C for 5 h, distill under reduced pressure, wash the crude product with petroleum ether, then add it to ethanol, evaporate by heating, cool and crystallize to obtain a dihistidine-based alkane.

[0027] (2) Add 1 L of ethanol, 0.1 mol of dihistidine-based alkane, and 10 mL of an aqueous solution containing 0.092 mol of glutaraldehyde into a reaction bottle equipped with a condenser reflux tube, heat to 55°C, react for 18 h, dry to remove ethanol and water, wash the product with ethanol, and dry to obtain a modified dispersant.

[0028] (3) Add 400 g of n-butanol, 400 g of alumina powder, and 45 g of modified dispersant into a high-speed disperser, disperse at 40°C for 6 h, add 1 kg of epoxy resin E44, 4 g of leveling agent, and 15 g of defoaming agent, disperse at 30°C for 20 min, and then add 36 g of 2-methylimidazole to obtain an insulating glass finish for electrical equipment.

[0029] Example 3 (1) Add 1 L of ethanol, 0.1 mol of dihistidine-based alkane (prepared in Example 1), and 10 mL of an aqueous solution containing 0.1 mol of glutaraldehyde into a reaction bottle equipped with a condenser reflux tube, heat to 70°C, react for 12 h, dry to remove ethanol and water, wash the product with ethanol, and dry to obtain a modified dispersant.

[0030] (2) Into a high-speed disperser, 550 g of isopropyl alcohol, 500 g of alumina powder, and 60 g of the modified dispersant were added, and sheared and dispersed at 70°C for 4 h. Then, 1 kg of epoxy resin E44, 10 g of a leveling agent, and 8 g of a defoaming agent were added, and sheared and dispersed at 30°C for 20 min. Then, 42 g of 2-ethyl-4-methylimidazole was added to obtain an insulating glass finish for electrical equipment.

[0031] Example 4 (1) Into a reaction bottle equipped with a condenser reflux tube, 1 L of ethanol, 0.1 mol of di-histidine alkane (prepared in Example 1), and 10 mL of an aqueous solution containing 0.1 mol of glutaraldehyde were added, and heated to 60°C, and reacted for 12 h. The ethanol and water were removed by drying, and the product was washed with ethanol and dried to obtain a modified dispersant.

[0032] (2) Into a high-speed disperser, 550 g of isopropyl alcohol, 500 g of alumina powder, and 60 g of the modified dispersant were added, and sheared and dispersed at 70°C for 4 h. Then, 1 kg of epoxy resin E44, 10 g of a leveling agent, and 8 g of a defoaming agent were added, and sheared and dispersed at 30°C for 20 min. Then, 42 g of 2-ethyl-4-methylimidazole was added to obtain an insulating glass finish for electrical equipment.

[0033] Comparative Example 1, the difference between this comparative example and Example 1 is that the modified dispersant is not added.

[0034] (1) Into a high-speed disperser, 500 g of isopropyl alcohol, 300 g of alumina powder, and 30 g of stearic acid were added, and sheared and dispersed at 50°C for 3 h. Then, 1 kg of epoxy resin E44, 8 g of a leveling agent, and 6 g of a defoaming agent were added, and sheared and dispersed at 20°C for 40 min. Then, 45 g of 2-ethyl-4-methylimidazole was added to obtain an insulating glass finish for electrical equipment.

[0035] Comparative Example 2, the difference between this comparative example and Example 1 is that the modified dispersant is replaced with stearic acid.

[0036] (1) Into a high-speed disperser, 500 g of isopropyl alcohol, 300 g of alumina powder, and 30 g of stearic acid were added, and sheared and dispersed at 50°C for 3 h. Then, 1 kg of epoxy resin E44, 8 g of a leveling agent, and 6 g of a defoaming agent were added, and sheared and dispersed at 20°C for 40 min. Then, 45 g of 2-ethyl-4-methylimidazole was added to obtain an insulating glass finish for electrical equipment.

[0037] Comparative Example 3, the difference between this comparative example and Example 1 is that the modified dispersant is replaced with di-histidine alkane.

[0038] (1) Add 500 g of isopropyl alcohol, 300 g of aluminum oxide powder, and 30 g of di-histidine-based alkane to a high-speed disperser, shear disperse at 50°C for 3 h, add 1 kg of epoxy resin E44, 8 g of leveling agent, and 6 g of defoaming agent, shear disperse at 20°C for 40 min, add 45 g of 2-ethyl-4-methyl imidazole, and obtain an insulating glass topcoat for electrical equipment.

[0039] Comparative Example 4, which is different from Example 1, is that polyacrylic acid is used instead of the modified dispersant.

[0040] (1) Add 500 g of isopropyl alcohol, 300 g of aluminum oxide powder, and 30 g of di-histidine-based alkane to a high-speed disperser, shear disperse at 50°C for 3 h, add 1 kg of epoxy resin E44, 8 g of leveling agent, and 6 g of defoaming agent, shear disperse at 20°C for 40 min, add 45 g of 2-ethyl-4-methyl imidazole, and obtain an insulating glass topcoat for electrical equipment.

[0041] The topcoat is applied to the surface of tinplate, cured at 80°C for 2 h, and then cured at 120°C for 3 h to form a paint film, the volume resistivity is tested according to GB / T1410-2006, and the wear resistance is tested according to GB / T 1768-2006. The paint is poured into a mold, cured at 80°C for 3 h, and then cured at 120°C for 5 h to form a cast body, and the impact strength is tested according to GB / T2567-2021.

[0042] Table 1 Performance of the paint

[0043] Compared with Comparative Examples 1-4, the epoxy resin topcoat of Examples 1-4 has higher volume resistivity and impact strength, and lower friction quality loss, and has better insulation performance, toughness, and wear resistance, mainly because the modified dispersant contains a large amount of carboxyl groups, which can achieve surface modification of the aluminum oxide powder, and the long-chain alkane and polymer molecular chain contained therein can play a steric hindrance effect, thereby reducing the agglomeration of the aluminum oxide, uniformly dispersing in the epoxy resin topcoat, forming an insulating network, improving the volume resistivity and insulation performance of the epoxy resin, and improving the wear resistance. The modified dispersant contains imidazole groups, which can participate in the curing reaction of the epoxy resin, thereby chemically bonding the polymer molecular chain containing flexible alkyl groups to the epoxy resin, which has a good toughening effect on the epoxy resin, and at the same time improves the interfacial performance of the aluminum oxide and the epoxy resin, and improves the compatibility of the aluminum oxide and the epoxy resin, thereby improving the impact strength and toughness of the epoxy resin.

[0044] The above embodiments only express several implementation ways of the present application, and the description is specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An insulating glass coating for electrical equipment, characterized in that, The topcoat comprises epoxy resin, solvent, alumina powder, modified dispersant, leveling agent, defoamer and curing agent in a mass ratio of 100:(40-55):(30-60):(3-8):(0.4-1):(0.6-1.5):(3.6-4.5); The preparation method of the modified dispersant includes: (1) Add dichloromethane, N-Boc-histidine, dibromoalkanes and potassium carbonate to a reaction flask equipped with a reflux condenser, stir the reaction, filter and add trifluoroacetic acid to the filtrate, continue the reaction, distill under reduced pressure, wash the crude product and recrystallize to purify it to obtain dihistidine-based alkanes. (2) Add an aqueous solution of ethanol, dihistidine-based alkanes and glutaraldehyde to a reaction flask equipped with a reflux condenser. After the reaction, dry the product to remove ethanol and water, wash the product with ethanol, and dry it to obtain the modified dispersant.

2. The insulating glass coating for electrical equipment according to claim 1, characterized in that, The solvent includes isopropanol or n-butanol.

3. The insulating glass coating for electrical equipment according to claim 1, characterized in that, The curing agent is an amine curing agent, including 2-ethyl-4-methylimidazole and 2-methylimidazole.

4. The insulating glass coating for electrical equipment according to claim 1, characterized in that, The molar ratio of N-Boc-histidine, dibromoalkane, and potassium carbonate in (1) is (2-2.4):1:(2.6-3.2).

5. The insulating glass coating for electrical equipment according to claim 4, characterized in that, The structural formula of the dibromoalkane is Br-(CH2). n -Br, where n is 10⁻¹⁸.

6. The insulating glass coating for electrical equipment according to claim 1, characterized in that, The temperature during the stirring reaction in (1) is 40-50℃, the reaction time is 7-10h, and the reaction is refluxed.

7. The insulating glass coating for electrical equipment according to claim 1, characterized in that, The temperature during the continued reaction in (1) is 20-30℃, and the reaction time is 3-5h.

8. The insulating glass coating for electrical equipment according to claim 1, characterized in that, The molar ratio of dihistidine-based alkane and glutaraldehyde in (2) is 1:(0.92-1).

9. The insulating glass coating for electrical equipment according to claim 1, characterized in that, The reaction temperature in (2) is 55-70℃ and the reaction time is 12-18h.

10. A method for preparing an insulating glass topcoat for electrical equipment as described in any one of claims 1-8, characterized in that, The preparation method includes: adding solvent, alumina powder, and modified dispersant to a high-speed disperser; after shear dispersion, adding epoxy resin, leveling agent, and defoamer; and after shear dispersion, adding curing agent to obtain an insulating glass topcoat for electrical equipment.

Images