Low-thermal-conductivity thermal insulation coating for vertical mill shell

Abstract

The invention discloses a low-thermal-conductivity thermal insulation coating for a vertical mill shell, and belongs to the technical field of thermal insulation coatings. Comprising the following raw materials in parts by weight: 61-73 parts of modified organic silicon resin, 18-26 parts of modified hollow glass beads, 10-15 parts of expanded vermiculite, 0.5-1 part of a defoaming agent, 3-5 parts of a curing agent and 20-30 parts of a solvent. Wherein the expansion particles and the modified hollow glass beads have a synergistic effect to form a multi-layer thermal barrier structure, so that heat conduction is effectively hindered, and the long-term thermal insulation stability of the coating is improved; wherein heat-resistant groups in the modified organic silicon resin and the modified hollow glass beads greatly improve the heat resistance of the coating, and after the hollow glass beads are modified, the compatibility of the hollow glass beads and a resin matrix is improved, filler agglomeration is avoided, and the uniformity and performance stability of the coating are ensured. Therefore, the coating prepared by the invention solves the problem of high-temperature heat insulation of the vertical mill shell, has heat resistance and low thermal conductivity, and has important application value in the technical field of heat insulation coatings.

Description

Technical Field

[0001] This invention belongs to the field of thermal insulation coating technology, specifically, it relates to a low thermal conductivity thermal insulation coating for vertical mill housings. Background Technology

[0002] Vertical mills are widely used grinding equipment in industries such as cement, metallurgy, and power, primarily for crushing and grinding materials. As a major structural component, the mill shell operates in a high-temperature environment, especially when processing high-temperature materials or performing hot air drying, where the shell surface temperature can rise significantly. This high-temperature environment not only leads to thermal fatigue and decreased mechanical properties of the shell material but can also deteriorate the surrounding working environment, increase energy consumption, and even threaten operator safety. Traditional solutions often involve increasing the shell thickness or adding an external insulation layer, but these methods have significant limitations. Increasing the shell thickness significantly increases equipment weight and manufacturing costs, while external insulation layers often suffer from poor durability, easy detachment, or high maintenance costs. Therefore, developing a high-efficiency heat-insulating coating that can be directly applied to the inner surface of the vertical mill shell has become a pressing technical challenge for the industry.

[0003] Currently, the heat resistance of commonly available heat insulation coatings is insufficient. Since the vertical mill shell is in a high-temperature environment for a long time, the coating is prone to thermal aging, which shortens the service life of the coating. Therefore, it is urgent to solve this problem in order to meet the higher requirements of the heat insulation coating technology field. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a low thermal conductivity insulating coating for vertical mill housings.

[0005] The objective of this invention can be achieved through the following technical solutions: A low thermal conductivity insulating coating for vertical mill housings is prepared by the following steps: Modified silicone resin was added to a mixing tank. Modified hollow glass microspheres and expanded vermiculite were added sequentially under low-speed stirring. After stirring for 10-20 minutes, defoamer, curing agent and solvent were added sequentially. After stirring for 30-60 minutes under high-speed stirring, a low thermal conductivity insulating coating for vertical mill shells was obtained.

[0006] Furthermore, the rotation speed of the low-speed stirring is 200-300 r / min.

[0007] Furthermore, the high-speed stirring speed is 1200-1500 r / min.

[0008] Furthermore, the raw materials are as follows by weight: 61-73 parts modified silicone resin, 18-26 parts modified hollow glass microspheres, 10-15 parts expanded vermiculite, 0.5-1 parts defoamer, 3-5 parts curing agent, and 20-30 parts solvent.

[0009] Furthermore, the defoamer is an organosilicone defoamer.

[0010] Furthermore, the curing agent is one of dibutyltin dilaurate and dicumyl peroxide.

[0011] Furthermore, the solvent is a mixture of xylene and n-butanol in a mass ratio of 7:3.

[0012] Furthermore, the modified organosilicon resin is prepared through the following steps: A1. Add methyltrimethoxysilane and phenyltrimethoxysilane to the reaction vessel, stir and mix evenly, slowly add deionized water, control the temperature at 40-50℃, react for 2-3 hours to generate silanol prepolymer; A2. Add hydrochloric acid (12% by mass) to the reaction vessel to adjust the pH to 4-5, catalyze polycondensation, raise the temperature to 80-90℃, and continue the reaction for 3-4 hours. After the reaction is completed, remove the methanol byproduct by vacuum distillation and replace the solvent with xylene to obtain the MQ type silicone resin solution. A3. Add MQ type silicone resin solution and epoxy resin E-44 to the reaction vessel, heat to 90-100℃, stir for 1-2 hours to make the system uniform, then add tetraethyl orthosilicate as a crosslinking agent, and add dibutyltin dilaurate, heat to 110-120℃, react for 2-3 hours, the reaction is complete, filter, and obtain modified organosilicon resin.

[0013] Furthermore, the raw materials are as follows by weight: 30-35 parts methyltrimethoxysilane, 15-20 parts phenyltrimethoxysilane, 50-60 parts deionized water, 20-25 parts xylene, and 10-15 parts epoxy resin E-44.

[0014] The silicone resin was modified by using epoxy resin E-44. The epoxy groups reacted with the silanol groups to form Si-OC bonds, which improved the adhesion of the resin to the metal substrate. Flexible segments were introduced to reduce the brittleness of the pure silicone resin, making the coating less prone to cracking under high temperature and vibration.

[0015] Furthermore, the modified hollow glass microspheres are prepared through the following steps: B1. Calcine hollow glass microspheres at 600-700℃ for 1-2 hours to remove surface impurities. After cooling, add them to an ethanol-water solution (ethanol to water volume ratio of 1:9). After ultrasonic treatment for 10-20 minutes, add KH-550, heat to 65-70℃, stir and react for 3-4 hours. After the reaction is complete, filter under reduced pressure and dry to obtain pretreated hollow glass microspheres. B2. In a three-necked flask, cyanuric chloride and acetone are mixed, and then 3-amino-1,2,4-triazole and triethylamine are added. The mixture is stirred until the solid is completely dissolved, heated to 60℃-70℃, and refluxed for 3-4 hours. After the reaction is completed, the mixture is post-treated to obtain the modifier. B3. First, disperse the pretreated hollow glass microspheres in N,N-dimethylformamide and sonicate them for 30-40 minutes. Then, add them to a three-necked flask, and then add the modifier and triethylamine in sequence. After stirring and mixing evenly, heat to 70-80℃ and keep the temperature for 6-8 hours. After the reaction is complete, filter and wash three times with anhydrous ethanol and distilled water in sequence to obtain the modified hollow glass microspheres.

[0016] Furthermore, in step B1, the ratio of hollow glass microspheres, ethanol aqueous solution, and KH-550 is 10g:100mL:1.3-2.2g.

[0017] Furthermore, in step B2, the ratio of cyanuric chloride, acetone, 3-amino-1,2,4-triazole, and triethylamine is 19.1-20.3g:150mL:16.8g:20.2g.

[0018] Furthermore, in step B3, the ratio of the amount of pretreated hollow glass microspheres, N,N-dimethylformamide, modifier, and triethylamine is 10g:100mL:2.8-3.5g:1.5-1.8g.

[0019] The reaction formula for preparing the modifier is as follows: As can be seen from the reaction formula, in step B2, cyanuric chloride reacts with 3-amino-1,2,4-triazole to obtain a modifier. It should be noted that the molar ratio of cyanuric chloride to 3-amino-1,2,4-triazole must be strictly controlled at 1:2, and cyanuric chloride needs to be in excess to reduce side reactions.

[0020] From a performance perspective, the triazine and triazole rings contained in the modifier are both heat-resistant groups, which can improve the heat resistance of the matrix. In addition, the modifier can also improve the compatibility between hollow glass microspheres and the matrix, making the hollow glass microspheres more uniformly dispersed. Furthermore, because hollow glass microspheres have low thermal conductivity, they can reduce the overall thermal conductivity of the coating, improve the thermal insulation performance, and have better dispersibility, making it easier for the performance to be fully realized.

[0021] The beneficial effects of this invention are: 1. In this invention, expanded leeches and modified hollow glass microspheres are added to the raw materials to form a multi-layer thermal barrier structure, which effectively hinders heat conduction and improves the long-term thermal insulation stability of the coating. 2. This invention significantly improves the heat resistance of the coating by introducing modified organosilicon resin and heat-resistant groups (triazine ring, triazole ring), thus solving the problem of easy heat aging of traditional coatings under the high temperature environment of vertical mill. 3. Hollow glass microspheres are treated with triazine-triazole modifier to improve compatibility with the resin matrix, prevent filler agglomeration, and ensure coating uniformity and performance stability.

[0022] Therefore, the coating prepared by this invention solves the problem of high-temperature heat insulation of vertical mill shell, and has both heat resistance and low thermal conductivity, which has important application value in the field of heat insulation coating technology. Detailed Implementation

[0023] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 Preparation of modified hollow glass microspheres: B1. Calcine 10g of hollow glass microspheres at 600℃ for 1h to remove surface impurities. After cooling, add them to 100mL of ethanol-water solution (ethanol to water volume ratio of 1:9). After sonication for 10min, add 1.3g of KH-550, heat to 65℃, stir and react for 3h. After the reaction is complete, filter under reduced pressure and dry to obtain pretreated hollow glass microspheres. B2. In a three-necked flask, mix 19.1g of cyanuric chloride and 150mL of acetone, then add 16.8g of 3-amino-1,2,4-triazole and 20.2g of triethylamine, stir until the solid is completely dissolved, heat to 60℃, reflux for 3h, and after the reaction is complete, perform post-treatment to obtain the modifier. B3. First, disperse 10g of pretreated hollow glass microspheres in 100mL of N,N-dimethylformamide, sonicate for 30min, then add to a three-necked flask, then add 2.8g of modifier and 1.5g of triethylamine in sequence, stir and mix evenly, heat to 70℃, keep warm for 6h, after the reaction is complete, filter, and wash three times with anhydrous ethanol and distilled water in sequence to obtain modified hollow glass microspheres; Preparation of modified organosilicon resin: A1. Add 30g of methyltrimethoxysilane and 15g of phenyltrimethoxysilane to the reaction vessel, stir and mix evenly, slowly add 50g of deionized water, control the temperature at 40℃, react for 2h to generate silanol prepolymer. A2. Add hydrochloric acid (12% by mass) to the reaction vessel to adjust the pH to 4, catalyze polycondensation, raise the temperature to 80℃, and continue the reaction for 3 hours. After the reaction is completed, remove the methanol byproduct by vacuum distillation, and replace the solvent with 20g of xylene to obtain MQ type silicone resin solution. A3. Add MQ type silicone resin solution and 10g epoxy resin E-44 to the reaction vessel, heat to 90℃, stir for 1h to make the system uniform, then add tetraethyl orthosilicate as a crosslinking agent, and add dibutyltin dilaurate, heat to 110℃, react for 2h, the reaction is complete, filter to obtain modified organosilicon resin. A low thermal conductivity insulating coating for vertical mill housings is prepared by the following steps: Add 61g of modified silicone resin to a mixing tank. Under low-speed stirring at 200r / min, add 18g of modified hollow glass microspheres and 10g of expanded vermiculite in sequence. After stirring for 10min, add 0.5g of silicone defoamer BYK-022, 3g of dibutyltin dilaurate and 20g of solvent (obtained by mixing 14g of xylene and 6g of n-butanol). After stirring at high-speed stirring at 1200r / min for 30min, a low thermal conductivity insulating coating for vertical mill shell is obtained.

[0025] Example 2 Preparation of modified hollow glass microspheres: B1. Calcine 10g of hollow glass microspheres at 700℃ for 2h to remove surface impurities. After cooling, add them to 100mL of ethanol-water solution (ethanol to water volume ratio of 1:9). After sonication for 20min, add 2.2g of KH-550, heat to 70℃, stir and react for 4h. After the reaction is complete, filter under reduced pressure and dry to obtain pretreated hollow glass microspheres. B2. In a three-necked flask, 20.3 g of cyanuric chloride and 150 mL of acetone were mixed, and then 16.8 g of 3-amino-1,2,4-triazole and 20.2 g of triethylamine were added. The mixture was stirred until the solid was completely dissolved, heated to 70 °C, and refluxed for 4 h. After the reaction was completed, the mixture was post-treated to obtain the modifier. B3. First, disperse 10g of pretreated hollow glass microspheres in 100mL of N,N-dimethylformamide, sonicate for 40min, then add to a three-necked flask, then add 3.5g of modifier and 1.8g of triethylamine in sequence, stir and mix evenly, heat to 80℃, keep warm for 8h, after the reaction is complete, filter, and wash three times with anhydrous ethanol and distilled water in sequence to obtain modified hollow glass microspheres; Preparation of modified organosilicon resin: A1. Add 35g of methyltrimethoxysilane and 20g of phenyltrimethoxysilane to the reaction vessel, stir and mix evenly, slowly add 60g of deionized water, control the temperature at 50℃, and react for 2-3 hours to generate silanol prepolymer. A2. Add hydrochloric acid (12% by mass) to the reaction vessel to adjust the pH to 5, catalyze polycondensation, raise the temperature to 90℃, and continue the reaction for 4 hours. After the reaction is completed, remove the methanol byproduct by vacuum distillation, and replace the solvent with 25g of xylene to obtain MQ type silicone resin solution. A3. Add MQ type silicone resin solution and 15g epoxy resin E-44 to the reaction vessel, heat to 100℃, stir for 2h to make the system uniform, then add tetraethyl orthosilicate as a crosslinking agent, and add dibutyltin dilaurate, heat to 120℃, react for 3h, the reaction is complete, filter to obtain modified organosilicon resin. A low thermal conductivity insulating coating for vertical mill housings is prepared by the following steps: Add 67g of modified silicone resin to a mixing tank. Under low-speed stirring at 200r / min, add 22g of modified hollow glass microspheres and 12.5g of expanded vermiculite in sequence. After stirring for 15min, add 0.7g of silicone defoamer BYK-022, 4g of dicumyl peroxide and 30g of solvent (obtained by mixing 21g of xylene and 9g of n-butanol). After stirring at high-speed stirring at 1300r / min for 45min, a low thermal conductivity heat insulation coating for vertical mill shell is obtained.

[0026] Example 3 The difference between this embodiment and Embodiment 2 is that a low thermal conductivity insulating coating for a vertical mill housing is prepared through the following steps: 73g of modified silicone resin was added to a mixing tank. Under low-speed stirring at 300r / min, 26g of modified hollow glass microspheres and 15g of expanded vermiculite were added sequentially. After stirring for 20min, 1g of silicone defoamer BYK-022, 5g of dicumyl peroxide and 30g of solvent (obtained by mixing 21g of xylene and 9g of n-butanol) were added sequentially. After stirring for 60min at high-speed stirring at 1500r / min, a low thermal conductivity heat insulation coating for vertical mill shells was obtained.

[0027] Comparative Example 1 The only difference between this comparative example and Example 2 is that the same B1 step is used to obtain pretreated hollow glass microspheres, which are then directly used as raw materials for the coating to obtain a heat-insulating coating.

[0028] Comparative Example 2 The only difference between this comparative example and Example 2 is that 22g of ordinary hollow glass microspheres were used to prepare the heat-insulating coating.

[0029] The following performance tests were performed on Examples 1, 2, and 3 and Comparative Examples 1 and 2: Thermal conductivity was determined according to GB / T 10297-2015 standard; Heat resistance was determined according to GB / T 1735-2009 standard; The measurement results are shown in the table below: As can be seen from the table above, the coating prepared by the embodiments of the present invention solves the problem of high-temperature heat insulation of the vertical mill shell, and has both heat resistance and low thermal conductivity, which has important application value in the field of heat insulation coating technology.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A low thermal conductivity insulating coating for a vertical mill housing, characterized in that, It is prepared through the following steps: Modified silicone resin was added to a mixing tank. Modified hollow glass microspheres and expanded vermiculite were added sequentially under low-speed stirring. After stirring, defoamer, curing agent and solvent were added sequentially. After stirring at high speed, a low thermal conductivity insulating coating for vertical mill shells was obtained.

2. The low thermal conductivity insulating coating for a vertical mill housing according to claim 1, characterized in that, The raw materials are as follows by weight: 61-73 parts modified silicone resin, 18-26 parts modified hollow glass microspheres, 10-15 parts expanded vermiculite, 0.5-1 parts defoamer, 3-5 parts curing agent, and 20-30 parts solvent.

3. The low thermal conductivity insulating coating for a vertical mill housing according to claim 1, characterized in that, The modified hollow glass microspheres are prepared by the following steps: B1. Calcine hollow glass microspheres at 600-700℃ for 1-2 hours, cool them, add them to an ethanol aqueous solution, sonicate them for 10-20 minutes, add KH-550, heat them to 65-70℃, stir and react for 3-4 hours. Once the reaction is complete, pretreated hollow glass microspheres are obtained. B2. Mix cyanuric chloride and acetone, then add 3-amino-1,2,4-triazole and triethylamine, stir and heat to 60-70℃, reflux for 3-4 hours. After the reaction is complete, the modifier is obtained. B3. Disperse the pretreated hollow glass microspheres in N,N-dimethylformamide, sonicate them, add them to a flask, then add the modifier and triethylamine in sequence, stir and mix evenly, and react at 70-80℃ for 6-8 hours. After the reaction is complete, the modified hollow glass microspheres are obtained.

4. The low thermal conductivity insulating coating for a vertical mill housing according to claim 3, characterized in that, In step B1, the ratio of hollow glass microspheres, ethanol aqueous solution, and KH-550 is 10g:100mL:1.3-2.2g.

5. A low thermal conductivity insulating coating for a vertical mill housing according to claim 3, characterized in that, In step B2, the ratio of cyanuric chloride, acetone, 3-amino-1,2,4-triazole, and triethylamine is 19.1-20.3g:150mL:16.8g:20.2g.

6. A low thermal conductivity insulating coating for a vertical mill housing according to claim 3, characterized in that, In step B3, the ratio of the amount of pretreated hollow glass microspheres, N,N-dimethylformamide, modifier, and triethylamine is 10g:100mL:2.8-3.5g:1.5-1.8g.

7. A low thermal conductivity insulating coating for a vertical mill housing according to claim 1, characterized in that, The modified organosilicon resin is prepared by the following steps: A1. Add methyltrimethoxysilane and phenyltrimethoxysilane to the reaction vessel, stir and mix evenly, add deionized water dropwise, and react at 40-50℃ for 2-3 hours to generate silanol prepolymer; A2. Continue to add hydrochloric acid to the reaction vessel to adjust the pH to 4-5, raise the temperature to 80-90℃, and continue the reaction for 3-4 hours. Once the reaction is complete, an MQ type silicone resin solution is obtained. A3. Add MQ type silicone resin solution and epoxy resin E-44 to the reaction vessel, heat to 90-100℃, stir for 1-2 hours to make the system uniform, then add tetraethyl orthosilicate and dibutyltin dilaurate dropwise, heat to 110-120℃, react for 2-3 hours, the reaction is complete, filter to obtain modified organosilicon resin.

8. A low thermal conductivity insulating coating for a vertical mill housing according to claim 7, characterized in that, The raw materials are as follows by weight: 30-35 parts methyltrimethoxysilane, 15-20 parts phenyltrimethoxysilane, 50-60 parts deionized water, 20-25 parts xylene, and 10-15 parts epoxy resin E-44.

9. A low thermal conductivity insulating coating for a vertical mill housing according to claim 1, characterized in that, The speed of the low-speed stirring is 200-300 r / min.

10. A low thermal conductivity insulating coating for a vertical mill housing according to claim 1, characterized in that, The high-speed stirring speed is 1200-1500 r / min.

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