High-temperature-resistant putty coating for resisting ablation of rocket tail flame and preparation method of high-temperature-resistant putty coating

Abstract

The invention discloses a high-temperature-resistant putty coating for resisting rocket tail flame ablation and a preparation method of the high-temperature-resistant putty coating. According to the invention, through the synergistic effect of multiple components, the ablation resistance is greatly improved. The high aluminate cement is used as an inorganic cementing material, has excellent high temperature resistance, can maintain structural stability in a high temperature environment, and is not easy to soften or decompose. By adding the common wall putty powder, the construction performance and the adhesive capacity of a coating foundation are maintained, and it is ensured that the coating can be well attached to the wall of the tower. The coating is filled with the nanometer silicon oxide powder, the microstructure of the coating is refined, the porosity is reduced, meanwhile, a compact protection layer can be formed at the high temperature, and corrosion of high-temperature airflow and particulate matter is blocked. The latex powder enhances the flexibility of the coating, relieves stress concentration in the coating at high temperature, reduces the probability of cracking and stripping, and enables the coating to effectively resist ablation and maintain surface integrity when facing high-temperature scouring of rocket tail flame.

Description

Technical Field

[0001] This invention belongs to the field of aerospace materials technology, specifically a high-temperature resistant putty coating for resisting rocket exhaust ablation and its preparation method. Background Technology

[0002] Space launch towers are crucial facilities providing ground support for the testing, fueling, and launch of spacecraft such as rockets and satellites. The combustion of solid propellant in rockets generates high-temperature, high-speed streams of solid particles, increasing the erosion and ablation of the rocket's exhaust plume. This can cause severe erosion and ablation damage to critical equipment on the launch tower. The white putty coating (heat resistance limit 80-120℃) on the walls, columns, and ceilings of the main tower structure suffers severe ablation under the high temperatures of rocket launch, resulting in discoloration and large-scale peeling off of the exterior wall coating. Due to the even higher ambient temperature on the lower levels (1-2 floors) of the fixed platform, large patches of bald-like peeling occur, requiring extensive repainting work after launch.

[0003] However, the heat resistance of ordinary wall putty coatings in the existing technology is insufficient. Under the high temperature environment generated by rocket launch, the coating surface is prone to discoloration, cracking, and crumbling, and may even peel off in large areas. Especially in areas with higher temperatures, such as the lower level of the launch tower fixed platform, the coating peeling is more serious. After each launch, the old coating needs to be removed and reapplied, which consumes a lot of manpower and time and prolongs the repair cycle of the launch tower. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature resistant putty coating for resisting rocket exhaust erosion and its preparation method in order to solve the problems mentioned above.

[0005] The technical solution adopted in this invention is as follows: a high-temperature resistant putty coating for resisting rocket exhaust erosion, comprising 32-36 parts by weight of high aluminate cement, 32-36 parts by weight of ordinary wall putty coating, 28-32 parts by weight of water, 0.4-0.6 parts by weight of nano silica powder and 1.4-1.9 parts by weight of latex powder.

[0006] In a preferred embodiment, a method for preparing a high-temperature resistant putty coating for resisting rocket exhaust ablation includes the following steps: S1: Prepare the raw materials by weighing out 32-36 parts of high aluminate cement, 32-36 parts of ordinary wall putty powder, 0.4-0.6 parts of nano silica powder, 1.4-1.9 parts of latex powder, and 28-32 parts of water in the following proportions. S2: Add high aluminate cement, ordinary wall putty powder, and nano silica powder to the mixing equipment and dry mix for 2 minutes; S3: Take another container, dissolve the latex powder in water, and stir for 2 minutes until completely dissolved; S4: Add the dissolved latex powder aqueous solution to the dry mixture; S5: Control the mixing equipment to mix at low speed for 3 minutes to make the materials initially mixed evenly; S6: Adjust the mixing equipment to high speed and continue mixing for 2 minutes to obtain a uniform high-temperature resistant putty coating slurry.

[0007] In a preferred embodiment, in step S1, an electronic balance with an accuracy of 0.01g is used to weigh the raw materials. 42.5 grade high aluminate cement, ordinary interior wall putty powder, nano-silica powder with a particle size of 10-20nm, vinyl acetate-ethylene copolymer latex powder, and deionized water are selected as raw materials. 32 to 36 parts of high aluminate cement, 32 to 36 parts of ordinary wall putty powder, 0.4 to 0.6 parts of nano-silica powder, 1.4 to 1.9 parts of latex powder, and 28 to 32 parts of deionized water are weighed separately. The weighing process is carried out part by part, and the corresponding data is recorded after each type of raw material is weighed. The weighed raw materials are then placed separately into dry and sealed special containers for storage.

[0008] In a preferred embodiment, in step S2, the weighed high aluminate cement, ordinary wall putty powder, and nano silica powder are added together to a horizontal ribbon mixer with an effective volume of 100L. The feed inlet of the mixer is closed and the equipment is kept in a sealed state. The mixer is started and the speed is set to 150r / min. The mixer is stirred continuously for 2 minutes. The equipment is kept running stably during the stirring process. After the stirring is completed, the machine is stopped. A small amount of the mixture is taken and tested through a 100-mesh sieve to confirm that there are no lumpy particles remaining.

[0009] In a preferred embodiment, in step S3, a stainless steel mixing tank with an effective volume of 50L is selected, the weighed deionized water is poured into the tank, an electric stirrer with a power of 200W is started, the stirring speed is set to 300r / min, the weighed latex powder is slowly and evenly poured into the water along the inner wall of the mixing tank, and the stirring state is maintained throughout the process. The stirring is continued for 2 minutes, and the state of the solution is observed every 30 seconds to ensure that no dry powder particles remain at the bottom or on the wall of the tank.

[0010] In a preferred embodiment, in step S4, the horizontal ribbon mixer is started and the rotation speed is set to 50 r / min to keep the dry mixed material running at a low speed. The prepared latex powder aqueous solution is poured into the separatory funnel, and the separatory funnel valve is controlled to add the material to the mixer at a uniform rate of 5 L / min. The entire dripping process takes about 6 minutes. During the dripping process, the state of the material in the mixer is continuously observed to avoid the formation of clumps due to excessive water absorption in some areas.

[0011] In a preferred embodiment, in step S5, the speed of the horizontal ribbon mixer is adjusted to 80 r / min, and the mixed material is continuously stirred for 3 minutes. During the stirring process, the machine is stopped once every 1 minute, and a small amount of material is picked up with a glass rod to observe the dispersion state, ensuring that there are no dry powder lumps in the material. The mixer is kept in a sealed state during the stirring to avoid moisture evaporation affecting the material ratio.

[0012] In a preferred embodiment, in step S6, the speed of the horizontal ribbon mixer is adjusted to 300 r / min, and the material is continuously stirred at high speed for 2 minutes. The mixer is equipped with a circulating water cooling device to control the material temperature to not exceed 40°C during the stirring process. After the stirring is completed, the machine is stopped, and the slurry is transferred to a sealed container and left to stand for 5 minutes to allow the air bubbles inside the slurry to be naturally discharged.

[0013] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In this invention, the synergistic effect of multiple components significantly enhances the resistance to ablation. High-aluminate cement, as an inorganic cementitious material, possesses excellent high-temperature resistance, maintaining structural stability under high-temperature conditions and preventing easy softening or decomposition. The addition of ordinary wall putty powder maintains the construction performance and adhesion of the coating base, ensuring good adhesion of the coating to the tower wall surface. Nano-silica powder fills the interior of the coating, refining its microstructure, reducing porosity, and forming a dense protective layer at high temperatures to block the erosion of high-temperature airflow and particles. Latex powder enhances the flexibility of the coating, alleviates stress concentration within the coating at high temperatures, and reduces the probability of cracking and peeling. The rational combination of various raw materials allows the coating to effectively resist ablation and maintain surface integrity when facing the high-temperature impact of rocket exhaust.

[0014] 2. In this invention, the preparation method is simple to operate, easy to apply on-site, and can be directly coated on the tower wall. Precise control of stirring parameters and time in each step of the preparation process ensures the uniformity of the slurry, resulting in stable and consistent coating performance. In on-site verification after rocket launch, the new ablation-resistant putty coating exhibited excellent ablation resistance. Compared with traditional putty coatings, there was no large-area peeling or cracking on the surface, only minor traces. This significantly reduces the workload of post-launch repairs, eliminating the need for frequent removal and re-application of the old coating, reducing labor and time costs, shortening the launch tower repair cycle, improving the utilization efficiency of the launch pad, and providing a reliable guarantee for the smooth conduct of subsequent rocket launch missions. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating the process principle of the present invention; Figure 2 This is a schematic diagram comparing the ablation resistance tests of laboratory putty coatings in this invention; Figure 3 This is a schematic diagram of the test location for the ablation-resistant putty coating in this invention; Figure 4 This is a schematic diagram of the ablation-resistant putty coating construction process in this invention; Figure 5 This is a schematic diagram comparing the post-launch test conditions of the putty coating in this invention (rocket launch on October 17, 2025); Figure 6 This is a schematic diagram of the comparative test of the column refractory putty coating in this invention (rocket launch on October 17, 2025); Figure 7 This is a detailed comparison diagram of the ablation-resistant putty coating and the ordinary putty coating in this invention; Figure 8 The results of the ablation resistance test of the putty coating in this invention are compared, where (a) is a normal putty coating, (b) is an ablation-resistant putty coating, (c) is an enlarged view of the normal putty coating, and (d) is an enlarged view of the ablation-resistant putty coating. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] Example 1: Reference Figure 1-7 A high-temperature resistant putty coating for resisting rocket exhaust erosion comprises 32-36 parts by weight of high aluminate cement, 32-36 parts by weight of ordinary wall putty coating, 28-32 parts by weight of water, 0.4-0.6 parts by weight of nano-silica powder, and 1.4-1.9 parts by weight of latex powder.

[0018] A method for preparing a high-temperature resistant putty coating for resisting rocket exhaust ablation includes the following steps: S1: Prepare the raw materials by weighing out 32-36 parts of high aluminate cement, 32-36 parts of ordinary wall putty powder, 0.4-0.6 parts of nano silica powder, 1.4-1.9 parts of latex powder, and 28-32 parts of water in the following proportions. S2: Add high aluminate cement, ordinary wall putty powder, and nano silica powder to the mixing equipment and dry mix for 2 minutes; S3: Take another container, dissolve the latex powder in water, and stir for 2 minutes until completely dissolved; S4: Add the dissolved latex powder aqueous solution to the dry mixture; S5: Control the mixing equipment to mix at low speed for 3 minutes to make the materials initially mixed evenly; S6: Adjust the mixing equipment to high speed and continue mixing for 2 minutes to obtain a uniform high-temperature resistant putty coating slurry.

[0019] In step S1, an electronic balance with an accuracy of 0.01g is used to weigh the raw materials. 42.5 grade high aluminate cement, ordinary wall putty powder for building interior walls, nano-silica powder with a particle size of 10-20nm, vinyl acetate-ethylene copolymer latex powder, and deionized water are selected as raw materials. 32 to 36 parts of high aluminate cement, 32 to 36 parts of ordinary wall putty powder, 0.4 to 0.6 parts of nano-silica powder, 1.4 to 1.9 parts of latex powder, and 28 to 32 parts of deionized water are weighed separately. The weighing process is carried out one part at a time. After weighing each type of raw material, the corresponding data is recorded. The weighed raw materials are placed in dry and sealed special containers for separate storage.

[0020] In step S2, the weighed high aluminate cement, ordinary wall putty powder, and nano silica powder are added together into a horizontal ribbon mixer with an effective volume of 100L. The feed inlet of the mixer is closed and the equipment is kept in a sealed state. The mixer is started and the speed is set to 150r / min. The mixer is continuously stirred for 2 minutes. During the stirring process, the equipment is kept running stably. After the stirring is completed, the machine is stopped. A small amount of the mixture is taken and tested through a 100-mesh sieve to confirm that there are no lumpy particles remaining.

[0021] In step S3, select a stainless steel mixing tank with an effective volume of 50L, pour the weighed deionized water into the tank, start the electric stirrer with a power of 200W, set the stirring speed to 300r / min, slowly and evenly pour the weighed latex powder into the water along the inner wall of the mixing tank, keep stirring throughout the process, and continue stirring for 2 minutes. During this period, observe the state of the solution every 30 seconds to ensure that no dry powder particles remain at the bottom or on the wall of the tank.

[0022] In step S4, start the horizontal ribbon mixer and set the speed to 50 r / min to keep the dry mixed materials running at a low speed. Pour the prepared latex powder aqueous solution into the separatory funnel and control the separatory funnel valve to add it to the mixer at a uniform rate of 5 L / min. The entire dripping process takes about 6 minutes. During the dripping process, continuously observe the state of the material in the mixer to avoid clumping due to excessive water absorption in some areas.

[0023] In step S5, adjust the speed of the horizontal ribbon mixer to 80 r / min and continuously stir the mixed material for 3 minutes. During the stirring process, stop the machine once every 1 minute and use a glass rod to pick up a small amount of material to observe the dispersion state to ensure that there are no dry powder lumps in the material. Keep the mixer in a sealed state during the stirring period to avoid moisture evaporation affecting the material ratio.

[0024] In step S6, the speed of the horizontal ribbon mixer is adjusted to 300 r / min, and the material is continuously stirred at high speed for 2 minutes. The mixer is equipped with a circulating water cooling device to control the material temperature to not exceed 40℃ during the stirring process. After stirring, the machine is stopped, and the slurry is transferred to a sealed container and left to stand for 5 minutes to allow the air bubbles inside the slurry to be naturally expelled. Example Experiment Objective: In the ultra-high speed and ultra-high temperature real force thermal environment of rocket launch at the work station, in-situ tests were conducted on a local part of the tower wall to verify the actual effect of the new material's anti-ablation performance.

[0025] Example Test Materials: Main components and proportions (100 parts): 32-36 parts high aluminate cement, 32-36 parts ordinary wall putty coating, 28-32 parts water, 0.4-0.6 parts nano silica powder, and 1.4-1.9 parts latex powder.

[0026] Preparation process: First, dry mix high aluminate cement, ordinary wall putty powder, and nano silica powder for 2 minutes. Then, dissolve latex powder in water and stir for 2 minutes. Finally, mix the solution with the dry materials and stir at low speed for 3 minutes and at high speed for 2 minutes.

[0027] Following preliminary preparation and research, our project team independently developed a novel nano-ablation-resistant putty coating material. While maintaining the original properties of the putty coating, this material enhances its ablation resistance. The new material adds alumina powder to ordinary putty to improve its ablation resistance, and adds nano-silica to form nanoscale pores, allowing free water in the putty layer to escape through the pores at high temperatures, preventing large-area cracking of the coating. In addition, dispersants and other additives are added to improve the application performance of the ablation-resistant putty.

[0028] On September 22, 2025, laboratory tests were conducted to verify the currently used putty coating and the ablation-resistant putty coating of the examples. Figure 2 As shown, after the coating was burned at 1400℃ for 20 seconds, the surface of the current putty coating was found to be severely ablated, with large cracks, yellowing, and the coating becoming brittle and easy to peel off. In contrast, the surface of the new ablation-resistant putty coating showed almost no change, with only localized fine cracks.

[0029] Example test plan and procedure: The tests were conducted on walls and columns exhibiting typical ablation characteristics on a fixed platform on the first floor, as shown in the test locations. Figure 3 As shown, the test size was 20cm x 20cm. Before applying the refractory putty, the original putty coating was removed and sanded clean, and then the ablation resistant putty coating was directly brushed on.

[0030] To evaluate the effectiveness of the improvements, the following evaluation plan is proposed: Evaluation Scheme Table for the Effect of New Ablation-Resistant Putty Coating Ideal effect General effects No effect The new type of ablation-resistant putty coating does not exhibit yellowing, peeling, cracking, or carbonization, and the surface does not detach. The new type of ablation-resistant putty coating exhibits slight yellowing, peeling, cracking, and carbonization, with localized detachment. The new type of ablation-resistant putty coating exhibits yellowing, peeling, cracking, and carbonization, resulting in large-area detachment. Analysis of experimental results: On October 17, 2025, the rocket was launched. It was observed that large sections of the current putty coating had peeled off, while the ablation-resistant putty coating remained largely intact. The contrast was even more pronounced because the column was closer to the rocket's exhaust plume.

[0031] Taking the fire-resistant putty coating on a column as an example, it can be observed that the current putty coating peels off in large chunks, while the new fire-resistant putty coating only shows minor scouring marks, and the degree of erosion is even lower based on the color. Large chunks of peeling wall putty coating not only affect the appearance but also require further removal and repainting, while the new fire-resistant putty coating requires no repair; simply applying latex paint at the end restores the color.

[0032] A close-up comparison of the morphology of ordinary putty and the ablation-resistant putty of the example before and after rocket launch reveals that the ordinary putty coating peeled off after launch, exposing the wall surface and exhibiting severe ablation. In contrast, the ablation-resistant putty coating of the example remained almost intact after launch, with only minor pores and pits. This comparison verifies the improved ablation resistance of the ablation-resistant putty coating in the example, as well as the ability of nano-silica to conduct water vapor at high temperatures, thus preventing large-scale peeling of the coating.

[0033] Example 2: Figure 8 As shown, on December 9, 2025, after the rocket launch, the ablation effects of two types of putty coatings were compared on the side of a pillar 3 meters away from the rocket's exhaust plume. The test results showed that the ordinary putty coating peeled off in large patches, while the ablation-resistant putty coating showed almost no large-pattern peeling. After the launch, there was no need to remove or repair the putty coating; latex paint could be sprayed directly, saving time on post-launch wall repair.

[0034] In summary, the improved ablation-resistant putty coating exhibits better ablation resistance. Tests have verified that no large-scale peeling occurred after application. Further evaluation of its resistance to repeated erosion is planned. If used on a large scale, it can significantly reduce the workload of post-application wall repair, reducing the number of repairs from each application to 3-5 applications, thus shortening the post-application repair cycle.

[0035] In this invention, the synergistic effect of multiple components significantly enhances the resistance to ablation. High-aluminate cement, as an inorganic cementitious material, possesses excellent high-temperature resistance, maintaining structural stability under high-temperature environments and preventing easy softening or decomposition. The addition of ordinary wall putty powder maintains the base coat's workability and adhesion, ensuring good adhesion to the tower wall. Nano-silica powder fills the coating's interior, refining its microstructure, reducing porosity, and forming a dense protective layer at high temperatures to block the erosion of high-temperature airflow and particles. Latex powder enhances the coating's flexibility, alleviates stress concentration within the coating at high temperatures, and reduces the probability of cracking and peeling. The rational combination of various raw materials allows the coating to effectively resist ablation and maintain surface integrity when facing the high-temperature impact of rocket exhaust.

[0036] This invention features a simple preparation method that is easy to operate and apply on-site, allowing for direct coating on launch tower walls. Precise control of stirring parameters and time in each step of the preparation process ensures the uniformity of the slurry, resulting in stable and consistent coating performance. In on-site verification after rocket launch, the novel ablation-resistant putty coating exhibited excellent ablation resistance. Compared to traditional putty coatings, there was no large-area peeling or cracking, only minor traces. This significantly reduces post-launch repair workload, eliminating the need for frequent removal and re-application of the old coating, reducing labor and time costs, shortening the launch tower repair cycle, improving the utilization efficiency of the launch pad, and providing a reliable guarantee for the smooth conduct of subsequent rocket launch missions.

[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "include" or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the inclusion of a defined element by a statement does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-temperature resistant putty coating for resisting rocket exhaust ablation, characterized in that: It includes 32-36 parts by weight of high aluminate cement, 32-36 parts by weight of ordinary wall putty coating, 28-32 parts by weight of water, 0.4-0.6 parts by weight of nano silica powder and 1.4-1.9 parts by weight of latex powder.

2. The method for preparing a high-temperature resistant putty coating for resisting rocket exhaust erosion as described in claim 1, characterized in that: The method includes the following steps: S1: Prepare the raw materials by weighing out 32-36 parts of high aluminate cement, 32-36 parts of ordinary wall putty powder, 0.4-0.6 parts of nano silica powder, 1.4-1.9 parts of latex powder, and 28-32 parts of water in the following proportions. S2: Add high aluminate cement, ordinary wall putty powder, and nano silica powder to the mixing equipment and dry mix for 2 minutes; S3: Take another container, dissolve the latex powder in water, and stir for 2 minutes until completely dissolved; S4: Add the dissolved latex powder aqueous solution to the dry mixture; S5: Control the mixing equipment to mix at low speed for 3 minutes to make the materials initially mixed evenly; S6: Adjust the mixing equipment to high speed and continue mixing for 2 minutes to obtain a uniform high-temperature resistant putty coating slurry.

3. The method for preparing a high-temperature resistant putty coating for resisting rocket exhaust erosion as described in claim 1, characterized in that: In step S1, an electronic balance with an accuracy of 0.01g is used to weigh the raw materials. 42.5 grade high aluminate cement, ordinary interior wall putty powder, nano-silica powder with a particle size of 10-20nm, vinyl acetate-ethylene copolymer latex powder, and deionized water are selected as raw materials. 32 to 36 parts of high aluminate cement, 32 to 36 parts of ordinary wall putty powder, 0.4 to 0.6 parts of nano-silica powder, 1.4 to 1.9 parts of latex powder, and 28 to 32 parts of deionized water are weighed separately. The weighing process is carried out one part at a time, and the corresponding data is recorded after each type of raw material is weighed. The weighed raw materials are then placed separately into dry and sealed special containers for storage.

4. The method for preparing a high-temperature resistant putty coating for resisting rocket exhaust erosion as described in claim 1, characterized in that: In step S2, the weighed high aluminate cement, ordinary wall putty powder, and nano silica powder are added together into a horizontal ribbon mixer with an effective volume of 100L. The feed inlet of the mixer is closed and the equipment is kept in a sealed state. The mixer is started and the speed is set to 150r / min, and the mixture is stirred continuously for 2 minutes.

5. The method for preparing a high-temperature resistant putty coating for resisting rocket exhaust erosion as described in claim 1, characterized in that: In step S3, a stainless steel mixing tank with an effective volume of 50L is selected, the weighed deionized water is poured into the tank, the electric stirrer with a power of 200W is started, the stirring speed is set to 300r / min, the weighed latex powder is slowly and evenly poured into the water along the inner wall of the mixing tank, and the stirring state is maintained throughout the process for 2 minutes.

6. The method for preparing a high-temperature resistant putty coating for resisting rocket exhaust ablation as described in claim 1, characterized in that: In step S4, the horizontal ribbon mixer is started and the speed is set to 50 r / min to keep the dry mixed material running at a low speed. The prepared latex powder aqueous solution is poured into the separatory funnel, and the separatory funnel valve is controlled to add it to the mixer at a rate of 5 L / min. The entire dripping process takes about 6 minutes.

7. The method for preparing a high-temperature resistant putty coating for resisting rocket exhaust erosion as described in claim 1, characterized in that: In step S5, the speed of the horizontal ribbon mixer is adjusted to 80 r / min, and the mixed material is continuously stirred for 3 minutes. During the stirring process, the machine is stopped once every 1 minute, and a small amount of material is picked up with a glass rod to observe the dispersion state, ensuring that there are no dry powder lumps in the material.

8. The method for preparing a high-temperature resistant putty coating for resisting rocket exhaust ablation as described in claim 1, characterized in that: In step S6, the speed of the horizontal ribbon mixer is adjusted to 300 r / min, and the material is continuously stirred at high speed for 2 minutes. The mixer is equipped with a circulating water cooling device to control the material temperature to not exceed 40°C during the stirring process. After the stirring is completed, the machine is stopped, and the slurry is transferred to a sealed container and left to stand for 5 minutes to allow the air bubbles inside the slurry to be naturally discharged.

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