Preparation of special PVC (polyvinyl chloride) weld joint sealant for aluminum material

Abstract

The invention relates to the technical field of sealants, in particular to preparation of a special PVC welding seam sealant for an aluminum material. The sealant is prepared by the following specific steps: S1, preparing and premixing raw materials: S1.1, preparing the raw materials: accurately weighing the PVC resin, the plasticizer, the stabilizer, the thixotropic agent, the diluent, the common low-molecular polyamide, the high-amine low-molecular polyamide, the inorganic filler and the polyvinyl chloride resin according to the formula proportion, and S1.2, weighing the raw materials: accurately weighing the raw materials according to the formula proportion, and uniformly mixing the raw materials; according to the sealant, the polarity is remarkably enhanced, the adhesion problem caused by weak polarity of the surface of the aluminum material is effectively solved, the adhesion performance of the surface of the aluminum material is remarkably improved, so that the sealant can be more firmly adhered to the surface of the aluminum material, the leakage problem caused by poor adhesion is avoided, and the service life of the sealant is prolonged. And the sealing performance of the vehicle body is improved.

Description

Technical Field

[0001] The invention relates to the technical field of sealants, in particular to the preparation of a PVC weld sealant specially used for aluminum materials. Background Art

[0002] With the rapid development and popularization of new energy vehicle technology, lightweighting has become one of the important trends in automobile design. Aluminum has been widely used in the manufacturing of new energy vehicle bodies due to its light weight, high strength, corrosion resistance and good thermal conductivity. However, the chemical properties of the aluminum surface are significantly different from those of traditional steel, especially its weak surface polarity, which poses a huge challenge to weld sealing in body manufacturing.

[0003] Although traditional PVC weld sealants perform well in sealing welds of other metal materials, their polarity properties do not match the polarity of the aluminum surface, making it difficult to form effective adhesion on the aluminum surface. This not only affects the sealing performance of the weld, but may also cause cracks and leaks in the weld, thereby affecting the overall performance and safety of the vehicle. In order to solve this technical problem, researchers and engineers are constantly exploring new solutions. They found that by adding high-amine low-molecular polyamide to the formula of traditional PVC weld sealants, the polarity of the sealant can be significantly improved, thereby enhancing its adhesion performance on the aluminum surface. This discovery provides new ideas and technical paths for the preparation of PVC weld sealants specifically for aluminum.

[0004] In order to solve the adhesion problem caused by the weak polarity of the aluminum surface, the existing technology usually adopts the method of increasing the coating thickness and changing the coating structure to improve the adhesion performance of the sealant. However, these methods not only increase the manufacturing cost, but also may have a negative impact on the overall performance of the vehicle body. For example, increasing the coating thickness may increase the weight of the vehicle body, thereby reducing the cruising range of new energy vehicles; and changing the coating structure may affect the weather resistance and sealing performance of the sealant.

[0005] However, most of the existing solutions focus on adjusting the formula of sealants, adding adhesion aids, and increasing the curing temperature. These methods often have the following problems: First, it is necessary to change the original baking process of the OEM, which increases production costs and process complexity; second, the use of adhesion aids may introduce new chemical components, affecting the environmental protection and safety of the car body; third, high-temperature curing may cause deformation or performance degradation of aluminum. Moreover, due to its weak surface polarity, aluminum has poor compatibility with many sealant materials, making it difficult for sealants to form stable and firm adhesion on the aluminum surface, which not only affects the sealing performance of the car body, but may also cause the sealant to fall off and crack during long-term use, thereby reducing the overall performance and service life of the car. Summary of the invention

[0006] Technical issues solved

[0007] In view of the above-mentioned shortcomings of the prior art, the present invention provides a preparation method of a PVC weld sealant specifically for aluminum materials. By adding high-amine low-molecular polyamide to the traditional PVC weld sealant formula, the polarity of the sealant is enhanced, thereby effectively solving the adhesion problem caused by the weak polarity of the aluminum surface. The sealant of the present invention can form a strong adhesion on the aluminum material by baking without changing the original baking process of the main engine factory, and there is no need to increase the coating thickness or change the coating structure, and has significant economic and social benefits.

[0008] Technical Solution

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0010] A preparation method of a PVC weld sealant for aluminum materials, wherein the specific steps of the sealant are as follows:

[0011] S1. Raw material preparation and premixing:

[0012] S1.1. Raw material preparation: accurately weigh PVC resin, plasticizer, stabilizer, thixotropic agent, diluent, ordinary low molecular weight polyamide, high amine low molecular weight polyamide, inorganic filler and polyvinyl chloride resin according to the formula ratio;

[0013] S1.2, weighing raw materials: according to the formula ratio, accurately weigh various raw materials and ensure that the weighing accuracy is within ±0.1%;

[0014] S1.3, Thickener synthesis: weighed ordinary low molecular weight polyamide and high amine low molecular weight polyamide are put into a mixing device, and fully mixed and stirred to make the two polyamides evenly blended to form a composite thickener. The time and speed of mixing and stirring are controlled to ensure the stability of the performance of the thickener. During the stirring process, the state change of the mixture is observed to ensure that there is no agglomeration and unevenness;

[0015] S1.4, pre-mixing: diluent, viscosity enhancer, thixotropic agent and stabilizer are added in sequence. After each raw material is added, continuous stirring is performed for a period of time to ensure that the raw materials are fully mixed and uniform. The temperature and time of pre-mixing are controlled to avoid volatilization and deterioration of the raw materials;

[0016] S1.5. Adding inorganic fillers: gradually increase the stirring speed to ensure that the inorganic fillers can be evenly dispersed in the mixture. During the process of adding the inorganic fillers, control the speed and amount of addition, observe the state changes of the mixture, and ensure that the inorganic fillers are fully mixed with other raw materials;

[0017] S1.6. Add PVC resin: slowly add PVC resin to the mixture and continue stirring. The stirring time and speed should be adjusted according to the state of the resin mixture to ensure that the resin is completely dispersed and evenly distributed. During the stirring process, observe the changes in the viscosity and fluidity of the mixture, and adjust the stirring parameters in time to ensure that the PVC resin is fully integrated with other raw materials to form a uniform sealant system.

[0018] S2. Vacuum degassing:

[0019] S2.1, Vacuum degassing treatment: Turn on the vacuum pump to perform vacuum degassing treatment on the material. By creating a negative pressure environment, bubbles and volatile impurities in the material can be removed to improve the quality and performance of the sealant;

[0020] S2.2, monitor vacuum degree and degassing time: During the degassing process, continue to perform negative pressure stirring to make the material more uniform, and adjust the stirring speed and time according to the material state and degassing effect;

[0021] S2.3, Vacuum stirring: Vacuum and stir the evenly mixed materials to further remove bubbles and ensure that the materials are evenly mixed. The stirring speed and time should be adjusted according to the state of the materials and the degassing effect. During the vacuum stirring process, keep the vacuum stable to prevent air from re-entering the materials. At the same time, observe the changes in the state of the materials to ensure that no new bubbles are generated.

[0022] S3. Sampling, testing and adjustment:

[0023] S3.1, Sampling and testing: adjust the viscosity by adding liquid materials for aging, and conduct sampling and testing, including viscosity, flow rate, adhesion, and odor;

[0024] S3.2, Adjustment: According to the test results, adjust the content of the liquid material. If the test results do not meet the requirements, increase or decrease the amount of liquid material, and perform vacuum stirring again until the qualified standards are met. During the adjustment process, pay attention to controlling the adjustment range and speed to avoid adverse effects on the performance of the sealant. Record the adjustment process and results for traceability and quality control;

[0025] S3.3, qualified material discharge and barrel loading: after passing the inspection, the qualified mixture is extracted from the maturation kettle;

[0026] S3.4. Adjustment if unqualified: If the product fails the test, return and perform vacuum stirring again until it passes. Analyze the reasons for the failure and take corresponding adjustment measures, i.e. adjust the formula, increase the degassing time, and optimize the stirring parameters.

[0027] S4, screw pump extrusion canning:

[0028] S4.1. Extrusion filling: Use a screw pump to extract the qualified mixture from the aging kettle and extrude and fill it through an extruder.

[0029] Furthermore, the raw material ratio in S1.1 is: plasticizer: 25-35%, high amine low molecular weight polyamide: 1-2%, ordinary low molecular weight polyamide: 0.5-1%, diluent: 1-5%, polyvinyl chloride resin: 15-25%, thixotropic agent: 20-30%, inorganic filler: 15-25%, stabilizer: 1-3%.

[0030] Furthermore, the PVC weld sealant forms a strong adhesion after the aluminum body is baked at 140-160 degrees for more than 30 minutes. By compounding low-molecular polyamides with different polarities and low-molecular polyamides with higher polarity, the problem of insufficient polarity on the surface of the aluminum material and difficulty in adhesion is compensated. Without changing the original baking process of the main engine manufacturer, the PVC weld sealant forms a strong adhesion on the aluminum material.

[0031] Furthermore, the stirring time in the S1.4 premixing is 15-20 minutes, and the stirring speed is gradually increased from 50 revolutions per minute to 150 revolutions per minute.

[0032] Furthermore, after the inorganic filler is added to the S1.5, the stirring speed is increased to 200 revolutions per minute, and the stirring time is 10-15 minutes.

[0033] Furthermore, the S1.6 adjusts the mixing time and temperature, the mixing time is 5 minutes, the temperature is 100° C., and the rotation speed is 300 rpm, so that various components are evenly dispersed in the PVC resin.

[0034] Furthermore, the S2 performs vacuum degassing treatment on the material by applying an absolute pressure reaching a vacuum degree of -0.08 MPa, and the degassing time is continued for 15 minutes.

[0035] Furthermore, the natural cooling method in S3.1 is used to cool to room temperature, and the rubber strips with no defects in appearance, dimensional deviation of ±0.5mm, odor level ≤2, and qualified sealing test are packaged, and an antibacterial agent is added, and the added amount is 0.1% of the total weight of the sealant.

[0036] Furthermore, the S3.2 adjustment uses an aluminum plate for testing adhesion.

[0037] Furthermore, the PVC polyvinyl chloride weld sealant is a paste sealant composed of a plasticizer, a diluent, a viscosity enhancer, a thixotropic agent, an inorganic filler and a pigment. After being heated and plasticized, it becomes an elastomer with a certain bonding strength. It is wear-resistant, flexural-resistant and chemical-resistant, and is widely used in the sealing of internal and external welds of car bodies.

[0038] Beneficial Effects

[0039] Compared with the known public technology, the technical solution provided by the present invention has the following advantages:

[0040] Beneficial effects:

[0041] 1. By adding high-amine low-molecular polyamide to the traditional PVC weld sealant formula, the sealant of the present invention significantly enhances polarity, effectively solves the adhesion problem caused by weak polarity on the aluminum surface, and significantly improves the adhesion performance of the aluminum surface. This enables the sealant to adhere more firmly to the aluminum surface, avoids leakage problems caused by poor adhesion, and improves the sealing performance of the vehicle body.

[0042] 2. The sealant of the present invention can form strong adhesion on aluminum by baking without changing the original baking process of the main engine factory, which means that there is no need to make major adjustments to the existing production process, reducing production costs and process complexity, reducing production costs and process costs, eliminating the pre-treatment and electrophoresis steps in the traditional coating process, and significantly reducing construction costs and manufacturing costs. This not only improves production efficiency, but also reduces the operating costs of the enterprise.

[0043] 3. The aluminum-specific PVC weld sealant of the present invention can effectively reduce the weight of the vehicle body, because the density of aluminum is much lower than that of traditional steel. The lightweight vehicle body is conducive to improving the cruising range of new energy vehicles and meeting the market demand for high-performance, low-energy consumption new energy vehicles. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the present invention is described clearly and completely. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The present invention will be further described below in conjunction with the embodiments.

[0046] A preparation method of a PVC weld sealant for aluminum materials, wherein the specific steps of the sealant are as follows:

[0047] S1. Raw material preparation and premixing:

[0048] S1.1. Raw material preparation: accurately weigh PVC resin, plasticizer, stabilizer, thixotropic agent, diluent, ordinary low molecular weight polyamide, high amine low molecular weight polyamide, inorganic filler and polyvinyl chloride resin according to the formula ratio;

[0049] S1.2, weighing raw materials: according to the formula ratio, accurately weigh various raw materials and ensure that the weighing accuracy is within ±0.1%;

[0050] S1.3, Thickener synthesis: weighed ordinary low molecular weight polyamide and high amine low molecular weight polyamide are put into a mixing device, and fully mixed and stirred to make the two polyamides evenly blended to form a composite thickener. The time and speed of mixing and stirring are controlled to ensure the stability of the performance of the thickener. During the stirring process, the state change of the mixture is observed to ensure that there is no agglomeration and unevenness;

[0051] S1.4, pre-mixing: diluent, viscosity enhancer, thixotropic agent and stabilizer are added in sequence. After each raw material is added, continuous stirring is performed for a period of time to ensure that the raw materials are fully mixed and uniform. The temperature and time of pre-mixing are controlled to avoid volatilization and deterioration of the raw materials;

[0052] S1.5. Adding inorganic fillers: gradually increase the stirring speed to ensure that the inorganic fillers can be evenly dispersed in the mixture. During the process of adding the inorganic fillers, control the speed and amount of addition, observe the state changes of the mixture, and ensure that the inorganic fillers are fully mixed with other raw materials;

[0053] S1.6. Add PVC resin: slowly add PVC resin to the mixture and continue stirring. The stirring time and speed should be adjusted according to the state of the resin mixture to ensure that the resin is completely dispersed and evenly distributed. During the stirring process, observe the changes in the viscosity and fluidity of the mixture, and adjust the stirring parameters in time to ensure that the PVC resin is fully integrated with other raw materials to form a uniform sealant system.

[0054] S2. Vacuum degassing:

[0055] S2.1, Vacuum degassing treatment: Turn on the vacuum pump to perform vacuum degassing treatment on the material. By creating a negative pressure environment, bubbles and volatile impurities in the material can be removed to improve the quality and performance of the sealant;

[0056] S2.2, monitor vacuum degree and degassing time: During the degassing process, continue to perform negative pressure stirring to make the material more uniform, and adjust the stirring speed and time according to the material state and degassing effect;

[0057] S2.3, Vacuum stirring: Vacuum and stir the evenly mixed materials to further remove bubbles and ensure that the materials are evenly mixed. The stirring speed and time should be adjusted according to the state of the materials and the degassing effect. During the vacuum stirring process, keep the vacuum stable to prevent air from re-entering the materials. At the same time, observe the changes in the state of the materials to ensure that no new bubbles are generated.

[0058] S3. Sampling, testing and adjustment:

[0059] S3.1, Sampling and testing: adjust the viscosity by adding liquid materials for aging, and conduct sampling and testing, including viscosity, flow rate, adhesion, and odor;

[0060] S3.2, Adjustment: According to the test results, adjust the content of the liquid material. If the test results do not meet the requirements, increase or decrease the amount of liquid material, and perform vacuum stirring again until the qualified standards are met. During the adjustment process, pay attention to controlling the adjustment range and speed to avoid adverse effects on the performance of the sealant. Record the adjustment process and results for traceability and quality control;

[0061] S3.3, qualified material discharge and barrel loading: after passing the inspection, the qualified mixture is extracted from the maturation kettle;

[0062] S3.4. Adjustment if unqualified: If the product fails the test, return and perform vacuum stirring again until it passes. Analyze the reasons for the failure and take corresponding adjustment measures, i.e. adjust the formula, increase the degassing time, and optimize the stirring parameters.

[0063] S4, screw pump extrusion canning:

[0064] S4.1. Extrusion filling: Use a screw pump to extract the qualified mixture from the aging kettle and extrude and fill it through an extruder.

[0065] Embodiment 1

[0066] The present embodiment provides detailed data parameters of a preparation process of a PVC weld sealant for aluminum and achieves different welding effects by adjusting the ratio of the parameters. When preparing the PVC weld sealant for aluminum, first prepare the raw materials according to the following ratio: 30% plasticizer, 1.5% high amine low molecular weight polyamide, 0.75% ordinary low molecular weight polyamide, 3% diluent, 20% polyvinyl chloride resin, 25% thixotropic agent, 20% inorganic filler, and 2% stabilizer. Subsequently, the weighed raw materials are put into a mixing device in a certain order, and the raw materials are mixed in a high-speed mixer at 100°C and 300 rpm for 5 minutes to ensure that the raw materials are evenly dispersed. The viscosity is adjusted by adding liquid to mature, and sampling is performed to detect the viscosity, flow rate, adhesion, and odor. If the inspection fails, return and vacuum stir again until it passes. After the inspection passes, a screw pump is used to extract the qualified mixture from the maturation kettle, and the mixture is extruded, filled, packaged, and stored through an extruder.

[0067] Embodiment 2

[0068] The present embodiment provides detailed data parameters of a preparation process of a PVC weld sealant for aluminum and achieves different welding effects by adjusting the ratio of the parameters. When preparing the PVC weld sealant for aluminum, first prepare the raw materials according to the following ratio: 28% plasticizer, 1.8% high amine low molecular weight polyamide, 0.8% ordinary low molecular weight polyamide, 2% diluent, 18% polyvinyl chloride resin, 28% thixotropic agent, 22% inorganic filler, and 1.5% stabilizer. Subsequently, the weighed raw materials are put into a mixing device in a certain order, and the raw materials are mixed in a high-speed mixer at 100° C. and 300 rpm for 5 minutes to ensure that the raw materials are evenly dispersed. During the cooling process, an antibacterial agent accounting for 0.1% of the total weight is added, and the viscosity is adjusted by adding liquid material for aging, and sampling is performed to detect viscosity, flow rate, adhesion, and odor. For those that fail the inspection, return and vacuumize and stir until they are qualified. After passing the inspection, a screw pump is used to extract the qualified mixture from the aging kettle, and the qualified sealing strips are packaged and stored.

[0069] Embodiment 3

[0070] The present embodiment provides detailed data parameters of a preparation process of a PVC weld sealant for aluminum and achieves different welding effects by adjusting the ratio of the parameters. When preparing the PVC weld sealant for aluminum, first prepare the raw materials according to the following ratio: 32% plasticizer, 1.2% high amine low molecular weight polyamide, 0.6% ordinary low molecular weight polyamide, 4% diluent, 22% polyvinyl chloride resin, 22% thixotropic agent, 18% inorganic filler, and 2.5% stabilizer. Then, the weighed raw materials are put into a mixing device in a certain order, and the raw materials are mixed in a high-speed mixer at 100° C. and 300 rpm for 6 minutes to ensure that the raw materials are evenly dispersed. Then, the viscosity is adjusted by adding liquid material for aging, and sampling is performed to detect viscosity, flow rate, adhesion, and odor. For those that fail the inspection, return and vacuumize and stir until they are qualified. After passing the inspection, use a screw pump to extract the qualified mixture from the aging kettle and perform surface treatment. The cured rubber strips are naturally cooled to room temperature, and the qualified sealing rubber strips are packaged and stored.

[0071] Embodiment 4

[0072] In this embodiment, the formula and production process of the PVC weld sealant for aluminum are further optimized. The raw material ratio is as follows: 31% plasticizer, 1.4% high amine low molecular weight polyamide, 0.7% ordinary low molecular weight polyamide, 3.5% diluent, 21% polyvinyl chloride resin, 24% thixotropic agent, 19% inorganic filler, 2.2% stabilizer, and 0.2% of the total weight of ultraviolet absorber is added to improve the weather resistance of the sealant. In the mixing step, we use a more efficient high-speed mixer, set the temperature to 95°C, and the speed to 350 rpm, and extend the mixing time to 7 minutes to ensure that the raw materials are more evenly dispersed. The viscosity is adjusted by adding liquid for maturation, and sampling is carried out to test viscosity, flow rate, adhesion, and odor. For those that fail the inspection, return and vacuum stir until they pass. After passing the inspection, use a screw pump to extract the qualified mixture from the maturation kettle. Finally, during the cooling process, in addition to natural cooling, a forced air cooling stage is added to accelerate the cooling process. After cooling to room temperature, the qualified sealing strips are packaged and stored.

[0073] Embodiment 5

[0074] The present embodiment provides detailed data parameters of the preparation process of PVC weld sealant for aluminum materials, and achieves different welding effects by adjusting the proportion of parameters. When preparing PVC weld sealant for aluminum materials, firstly, raw materials are prepared according to the following proportions: 30.5% plasticizer, 1.6% high amine low molecular weight polyamide, 0.5% bio-based low molecular weight polyamide (replacing part of ordinary low molecular weight polyamide), 3.2% diluent, 20.5% polyvinyl chloride resin, 23.5% thixotropic agent, 19.5% inorganic filler, 2.3% stabilizer, and 0.2% biodegradable Dissolve the additives, then put the weighed raw materials into the mixing equipment in a certain order. The raw materials are mixed in the high-speed mixer at 98°C and 300 rpm for 6 minutes to ensure that the raw materials are evenly dispersed. Then, the viscosity is adjusted by adding liquid for aging, and sampling is carried out to test the viscosity, flow rate, adhesion, and odor. If the inspection fails, return and vacuum stir until it passes. After the inspection passes, use a screw pump to extract the qualified mixture from the aging kettle and perform surface treatment. The cured strips are naturally cooled to room temperature, and the qualified sealing strips are packaged and stored.

[0075] Embodiment 6

[0076] This embodiment provides detailed data parameters of the preparation process of PVC weld sealant for aluminum materials, and achieves different welding effects by adjusting the ratio of parameters. When preparing PVC weld sealant for aluminum materials, firstly, raw materials are prepared according to the following ratio: 29% plasticizer, 1.7% high amine low molecular weight polyamide, 0.7% ordinary low molecular weight polyamide, 0.5% reinforcing fiber (such as glass fiber or carbon fiber), 3.3% diluent, 21.5% polyvinyl chloride resin, 22.5% thixotropic agent, 19% inorganic filler, 2% stabilizer, and then, The measured raw materials are put into the mixing equipment in a certain order. The raw materials are mixed in the high-speed mixer at 100°C and 300 rpm for 5 minutes to ensure that the raw materials are evenly dispersed. Then, the viscosity is adjusted by adding liquid for aging, and sampling is carried out to test the viscosity, flow rate, adhesion, and odor. If the inspection fails, it is returned for vacuum stirring until it passes. After passing the inspection, the qualified mixture is extracted from the aging kettle using a screw pump and surface treated. The cured strips are naturally cooled to room temperature, and the qualified sealing strips are packaged and stored.

[0077] The specific results are as follows:

[0078]

[0079] As shown in the above table, the present invention proposes a preparation technology of a PVC weld sealant specially used for aluminum materials. By adding high-amine low-molecular polyamide to the traditional PVC weld sealant formula, the polarity of the sealant is enhanced, thereby effectively solving the adhesion problem caused by the weak polarity of the aluminum surface. The sealant of the present invention can form a strong adhesion on the aluminum material by baking without changing the original baking process of the main engine factory, and there is no need to increase the coating thickness or change the coating structure, which has significant economic and social benefits.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements will 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. Preparation of a PVC weld sealant for aluminum, characterized in that: The specific steps of this sealant are: S1. Raw material preparation and premixing: S1.

1. Raw material preparation: accurately weigh PVC resin, plasticizer, stabilizer, thixotropic agent, diluent, ordinary low molecular weight polyamide, high amine low molecular weight polyamide, inorganic filler and polyvinyl chloride resin according to the formula ratio; S1.2, weighing raw materials: according to the formula ratio, accurately weigh various raw materials and ensure that the weighing accuracy is within ±0.1%; S1.3, Thickener synthesis: weighed ordinary low molecular weight polyamide and high amine low molecular weight polyamide are put into a mixing device, and fully mixed and stirred to make the two polyamides evenly blended to form a composite thickener. The time and speed of mixing and stirring are controlled to ensure the stability of the performance of the thickener. During the stirring process, the state change of the mixture is observed to ensure that there is no agglomeration and unevenness; S1.4, pre-mixing: diluent, viscosity enhancer, thixotropic agent and stabilizer are added in sequence. After each raw material is added, continuous stirring is performed for a period of time to ensure that the raw materials are fully mixed and uniform. The temperature and time of pre-mixing are controlled to avoid volatilization and deterioration of the raw materials; S1.

5. Adding inorganic fillers: gradually increase the stirring speed to ensure that the inorganic fillers can be evenly dispersed in the mixture. During the process of adding the inorganic fillers, control the speed and amount of addition, observe the state changes of the mixture, and ensure that the inorganic fillers are fully mixed with other raw materials; S1.

6. Add PVC resin: slowly add PVC resin to the mixture and continue stirring. The stirring time and speed should be adjusted according to the state of the resin mixture to ensure that the resin is completely dispersed and evenly distributed. During the stirring process, observe the changes in the viscosity and fluidity of the mixture, and adjust the stirring parameters in time to ensure that the PVC resin is fully integrated with other raw materials to form a uniform sealant system. S2. Vacuum degassing: S2.1, Vacuum degassing treatment: Turn on the vacuum pump to perform vacuum degassing treatment on the material. By creating a negative pressure environment, bubbles and volatile impurities in the material can be removed to improve the quality and performance of the sealant; S2.2, monitor vacuum degree and degassing time: During the degassing process, continue to perform negative pressure stirring to make the material more uniform, and adjust the stirring speed and time according to the material state and degassing effect; S2.3, Vacuum stirring: Vacuum and stir the evenly mixed materials to further remove bubbles and ensure that the materials are evenly mixed. The stirring speed and time should be adjusted according to the state of the materials and the degassing effect. During the vacuum stirring process, keep the vacuum stable to prevent air from re-entering the materials. At the same time, observe the changes in the state of the materials to ensure that no new bubbles are generated. S3. Sampling, testing and adjustment: S3.1, Sampling and testing: adjust the viscosity by adding liquid materials for aging, and conduct sampling and testing, including viscosity, flow rate, adhesion, and odor; S3.2, Adjustment: According to the test results, adjust the content of the liquid material. If the test results do not meet the requirements, increase or decrease the amount of liquid material, and perform vacuum stirring again until the qualified standards are met. During the adjustment process, pay attention to controlling the adjustment range and speed to avoid adverse effects on the performance of the sealant. Record the adjustment process and results for traceability and quality control; S3.3, qualified material discharge and barrel loading: after passing the inspection, the qualified mixture is extracted from the maturation kettle; S3.

4. Adjustment if unqualified: If the product fails the test, return and perform vacuum stirring again until it passes. Analyze the reasons for the failure and take corresponding adjustment measures, i.e. adjust the formula, increase the degassing time, and optimize the stirring parameters. S4, screw pump extrusion canning: S4.

1. Extrusion filling: Use a screw pump to extract the qualified mixture from the aging kettle and extrude and fill it through an extruder.

2. The preparation of a PVC weld sealant for aluminum materials according to claim 1, characterized in that: The raw material ratio in S1.1 is: plasticizer: 25-35%, high amine low molecular weight polyamide: 1-2%, ordinary low molecular weight polyamide: 0.5-1%, diluent: 1-5%, polyvinyl chloride resin: 15-25%, thixotropic agent: 20-30%, inorganic filler: 15-25%, stabilizer: 1-3%.

3. The preparation of a PVC weld sealant for aluminum materials according to claim 1, characterized in that: The PVC weld sealant forms strong adhesion after being baked at 140-160 degrees for more than 30 minutes on the aluminum body. The problem of insufficient polarity on the surface of the aluminum material and difficulty in adhesion is compensated by compounding low-molecular polyamides with different polarities and low-molecular polyamides with higher polarity. Without changing the original baking process of the main engine manufacturer, the PVC weld sealant forms strong adhesion on the aluminum material.

4. The preparation of a PVC weld sealant for aluminum materials according to claim 1, characterized in that: The stirring time in the S1.4 premixing is 15-20 minutes, and the stirring speed is gradually increased from 50 revolutions per minute to 150 revolutions per minute.

5. The preparation of a PVC weld sealant for aluminum materials according to claim 4, characterized in that: After the inorganic filler is added to the S1.5, the stirring speed is increased to 200 revolutions per minute, and the stirring time is 10-15 minutes.

6. The preparation of a PVC weld sealant for aluminum materials according to claim 5, characterized in that: The S1.6 adjusts the mixing time and temperature. The mixing time is 5 minutes, the temperature is 100° C., and the rotation speed is 300 rpm, so that various components are evenly dispersed in the PVC resin.

7. The preparation of a PVC weld sealant for aluminum materials according to claim 1, characterized in that: The S2 performs vacuum degassing treatment on the material by applying an absolute pressure reaching a vacuum degree of -0.08 MPa, and the degassing time is continued for 15 minutes.

8. The preparation of a PVC weld sealant for aluminum materials according to claim 1, characterized in that: The natural cooling method in S3.1 is used to cool the sealant to room temperature, and the sealant strips with no defects in appearance, size deviation of ±0.5mm, odor level ≤2, and qualified sealing test are packaged, and an antibacterial agent is added, and the added amount is 0.1% of the total weight of the sealant.

9. The preparation of a PVC weld sealant for aluminum materials according to claim 1, characterized in that: The S3.2 adjustment uses an aluminum plate for testing adhesion.

10. The preparation of a PVC weld sealant for aluminum materials according to claim 1, characterized in that: The PVC polyvinyl chloride weld sealant is a paste sealant composed of a plasticizer, a diluent, a viscosity enhancer, a thixotropic agent, an inorganic filler and a pigment. After being heated and plasticized, it becomes an elastomer with a certain bonding strength. It is wear-resistant, flex-resistant and chemical-resistant, and is widely used for sealing the internal and external welds of car bodies.

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