A method for treating the surface of an automotive weather strip with a wear-resistant coating

Abstract

The application relates to the technical field of automobile sealing strips, in particular to a surface wear-resistant coating treatment method for automobile sealing strips, which comprises the following steps: selecting an automobile sealing strip base material, sequentially performing surface oil removal, plasma activation and bottom coating treatment to obtain a pretreated base material, uniformly coating prepared organic silicon modified composite wear-resistant paint on the surface of the pretreated base material, and sequentially performing low-temperature pre-curing, medium-temperature cross-linking curing and high-temperature setting curing on the coated base material, and performing surface polishing and dust removal treatment on the cured sealing strip. Compared with the prior art, in the technical scheme provided by the application, the low-temperature pre-curing avoids the generation of bubbles in the curing process, the medium-temperature cross-linking curing forms a stable cross-linking network structure, the coating strength is improved, the high-temperature setting curing improves the wear resistance and weather resistance of the coating, and the problems of coating cracking and adhesion reduction are avoided in the gradient curing mode, so that the stability of the coating performance is ensured.

Description

Technical Field

[0001] This invention relates to the field of automotive sealing strip technology, and more specifically to a method for treating the surface of automotive sealing strips with a wear-resistant coating. Background Technology

[0002] Automotive sealing strips are key components of the car body, mainly serving to seal, prevent dust and water, reduce noise, and cushion shocks. Their surface is in constant contact and friction with the car body sheet metal, glass, door frame and other parts, and is also exposed to complex external environments, needing to withstand high and low temperature changes, ultraviolet radiation, rain erosion, oil stains and other tests. Therefore, surface wear resistance, adhesion and weather resistance are the core indicators that determine the service life and user experience of the sealing strip.

[0003] Currently, there are three main processes for wear-resistant treatment of automotive sealing strips: First, electrostatic flocking, which involves implanting flocking after coating the sealing strip with adhesive. While this can reduce friction noise, the flocking tends to fall off after long-term friction, affecting the cleanliness of the glass and the noise reduction effect. Moreover, its wear resistance is limited and cannot meet the needs of high-frequency use scenarios. Second, polyethylene (PE) strip composite process, which requires extruding PE strips through a special mold and then bonding them to the sealing strip substrate. This process is complex, has a low tolerance for error, and the temperature difference between PE and the substrate (such as EPDM rubber or TPV elastomer) can easily cause color differences, and the surface is prone to bumps and scratches. It is only suitable for non-exposed areas. Third, single spraying process, which often uses polyurethane coatings. This process requires multiple steps, has poor adhesion between the coating and the substrate, and is prone to peeling and flaking after long-term use. Furthermore, it is difficult to balance wear resistance and weather resistance, which cannot meet the development needs of lightweight and long-life new energy vehicles. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of easy shedding of electrostatic flocking, complex PE composite process and poor appearance, and weak adhesion and easy peeling of single spray coating in common processes. It provides a method for treating wear-resistant coating on the surface of automotive sealing strips, which achieves synergistic improvement of wear resistance, adhesion and weather resistance, while simplifying the process and reducing costs.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for applying a wear-resistant coating to the surface of automotive sealing strips includes the following steps:

[0007] S1. Select automotive sealing strip substrate, and sequentially perform surface degreasing, plasma activation, and primer treatment to obtain pretreated substrate;

[0008] S2. Preparation of organosilicon-modified composite wear-resistant coatings;

[0009] S3. The prepared organosilicon-modified composite wear-resistant coating is uniformly coated on the surface of the pretreated substrate;

[0010] S4. The coated substrate is subjected to low-temperature pre-curing, medium-temperature cross-linking curing, and high-temperature shaping curing in sequence to obtain an automotive sealing strip with a wear-resistant coating on the surface. The low-temperature pre-curing temperature is set to 80-90℃ and the time is set to 20-30min. The medium-temperature cross-linking curing temperature is set to 120-130℃ and the time is set to 40-60min. The high-temperature shaping curing temperature is set to 150-160℃ and the time is set to 15-20min.

[0011] S5. After curing, the sealing strip is surface-polished and dust-removed. Then, the coating adhesion, wear resistance, and weather resistance are tested. Unqualified products are returned for reprocessing, and qualified products are the finished products.

[0012] Preferably, in S1, surface degreasing specifically involves placing the sealing strip substrate in an ultrasonic cleaning tank, using a neutral degreasing agent, cleaning for 15-25 minutes at a temperature of 40-50℃ and an ultrasonic power of 300-400W, then rinsing with deionized water 3-5 times, and drying at 80-100℃ until the surface is free of moisture. The neutral degreasing agent is prepared by mixing 5-8 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 3-5 parts of cocamidopropyl betaine, and 87-92 parts of deionized water.

[0013] Preferably, plasma activation in S1 specifically involves placing the degreased and dried substrate into an atmospheric pressure plasma treatment device, using an Ar / O2 mixed gas, controlling the treatment power to be 150-200W, the treatment speed to be 2-3m / min, the treatment distance to be 5-8mm, and the treatment time to be 30-60s.

[0014] Preferably, the primer treatment in S1 specifically involves uniformly coating the surface of the plasma-activated substrate with a primer layer, the thickness of which is set to 10-20 μm, and then pre-baking at 60-70°C for 10-15 min.

[0015] Preferably, the silicone-modified composite wear-resistant coating in S2 comprises 40-60 parts of silicone-modified polyurethane resin, 10-18 parts of nano molybdenum disulfide, 8-15 parts of polytetrafluoroethylene micro powder, 3-6 parts of γ-mercaptopropyltriethoxysilane coupling agent, 2-5 parts of crosslinking agent, 5-10 parts of nano alumina, 0.5-1.5 parts of defoamer, 0.3-0.8 parts of leveling agent, and 10-20 parts of diluent.

[0016] Preferably, the organosilicon-modified polyurethane resin is prepared by mixing polyurethane resin and organosilicon monomer at a weight ratio of 8:2, adding 0.5-1 part of dibutyltin dilaurate catalyst, reacting at 80-90℃ for 2-3 hours, cooling to room temperature, adding 1-2 parts of antioxidant 1010, and stirring evenly.

[0017] Preferably, in S3, a high-voltage electrostatic spraying process is used to coat the silicone-modified composite wear-resistant coating onto the surface of the pretreated substrate, wherein the spraying voltage is set to 30-40kV, the spraying distance is set to 15-25cm, and the spraying speed is set to 1-2m / min.

[0018] Preferably, the wet film thickness of the silicone-modified composite wear-resistant coating in S3 applied to the surface of the pretreated substrate is set to 80-120 μm.

[0019] Preferably, in step S5, the coating surface is sanded with 1000-1200 grit sandpaper, and then the surface dust is blown away with compressed air.

[0020] Compared with the prior art, the technical solution provided by this invention removes the diluent in the coating by low-temperature pre-curing, avoiding the generation of bubbles during the curing process. Medium-temperature cross-linking curing promotes the cross-linking agent in the coating to play its role, forming a stable cross-linking network structure and improving the coating strength. High-temperature setting curing further strengthens the bond between the coating and the substrate, improving the wear resistance and weather resistance of the coating. In this way, the gradient curing method avoids problems such as coating cracking and decreased adhesion, ensuring the stability of coating performance. Detailed Implementation

[0021] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following specific embodiments are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0022] As a specific embodiment of the wear-resistant coating treatment method for automotive sealing strips provided by this invention, the method includes selecting an automotive sealing strip substrate, which is one of EPDM rubber, TPV elastomer, or foamed EPDM, to meet the usage requirements of different vehicle models. The substrate is then subjected to surface degreasing, plasma activation, and primer treatment sequentially to obtain a pre-treated substrate. Specifically, surface degreasing involves placing the sealing strip substrate in an ultrasonic cleaning tank, using a neutral degreasing agent with a pH of 7.5-8.5, and cleaning for 15-25 minutes at 40-50℃ and ultrasonic power of 300-400W. Afterward, it is rinsed 3-5 times with deionized water and dried at 80-100℃ until the surface is free of moisture. The neutral degreasing agent is prepared by mixing 5-8 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 3-5 parts of cocamidopropyl betaine, and 87-92 parts of deionized water, avoiding the corrosion of the substrate by traditional strong acid and alkali degreasing agents while ensuring thorough degreasing. Plasma activation specifically involves... After the oil is dried, the substrate is placed in an atmospheric pressure plasma treatment device using an Ar / O2 mixed gas with a volume ratio of Ar to O2 of 3:1. The treatment power is controlled at 150-200W, the treatment speed at 2-3m / min, the treatment distance at 5-8mm, and the treatment time at 30-60s. Through plasma activation, residual trace contaminants on the substrate surface can be thoroughly removed, the molecular bonds on the substrate surface can be broken, and polar groups such as hydroxyl and carboxyl groups can be introduced. At the same time, nanoscale pits are formed on the surface, which expands the contact area between the coating and the substrate and improves the adhesion of the subsequent primer and coating. The primer treatment specifically involves uniformly coating a primer with a thickness of 10-20μm onto the plasma-activated substrate surface, and then pre-baking at 60-70℃ for 10-15min. The primer is a polyurethane primer with 2-3 parts of γ-aminopropyltriethoxysilane coupling agent added to enhance the dual bonding force between the primer and the substrate, and between the primer and the wear-resistant coating, thus preventing the coating from peeling or falling off.

[0023] A silicone-modified composite wear-resistant coating was prepared. The coating, by weight, comprises 40-60 parts of silicone-modified polyurethane resin, 10-18 parts of nano-molybdenum disulfide, 8-15 parts of polytetrafluoroethylene (PTFE) micropowder, 3-6 parts of γ-mercaptopropyltriethoxysilane coupling agent, 2-5 parts of RelcaLink® series crosslinking agent, 5-10 parts of nano-alumina, 0.5-1.5 parts of defoamer, 0.3-0.8 parts of leveling agent, and 10-20 parts of diluent. The nano-molybdenum disulfide has a particle size of 50-100 nm, the PTFE micropowder has a particle size of 1-5 μm, and the nano-alumina has a particle size of 30-50 nm. By controlling the particle size of each nanoparticle, uniform dispersion in the coating is ensured, avoiding agglomeration. The nano-molybdenum disulfide utilizes its interlayer slip properties to achieve wear resistance. The three components work synergistically to address the imbalance in performance of existing single-filler modifications. The defoamer is a silicone defoamer, the leveling agent is a polyether-modified polysiloxane leveling agent, and the diluent is a 1:1 mixture of ethyl acetate and xylene. The silicone-modified polyurethane resin is prepared by mixing polyurethane resin and silicone monomers at a weight ratio of 8:2, adding 0.5-1 part of dibutyltin dilaurate catalyst, reacting at 80-90℃ for 2-3 hours, cooling to room temperature, adding 1-2 parts of antioxidant 1010, and stirring until homogeneous. The silicone-modified polyurethane resin combines the strong adhesion of polyurethane with the weather resistance and lubricity of silicone, providing excellent basic properties for the coating.

[0024] High-voltage electrostatic spraying is used to uniformly coat the prepared silicone-modified composite wear-resistant coating onto the surface of the pretreated substrate. The wet film thickness of the coating is controlled to be 80-120μm. The spraying voltage of high-voltage electrostatic spraying is 30-40kV, the spraying distance is 15-25cm, the spraying speed is 1-2m / min, and the spray gun movement speed is uniform to ensure uniform coating thickness and absence of defects such as sagging and pinholes. Compared with traditional spraying processes, high-voltage electrostatic spraying can improve the utilization rate of coatings, reduce waste, and improve the uniformity and density of the coating.

[0025] The coated substrate is subjected to low-temperature pre-curing, medium-temperature cross-linking curing, and high-temperature setting curing in sequence to obtain an automotive sealing strip with a wear-resistant coating. The low-temperature pre-curing temperature is 80-90℃ for 20-30 minutes to remove the thinner in the coating and avoid the formation of bubbles during curing. The medium-temperature cross-linking curing temperature is 120-130℃ for 40-60 minutes to promote the function of the cross-linking agent in the coating, form a stable cross-linking network structure, and improve the coating strength. The high-temperature setting curing temperature is 150-160℃ for 15-20 minutes to further strengthen the bond between the coating and the substrate, improve the wear resistance and weather resistance of the coating. Gradient curing avoids problems such as coating cracking and decreased adhesion caused by single-temperature curing, ensuring stable coating performance.

[0026] After curing, the sealing strip undergoes surface grinding and dust removal. Then, the coating's adhesion, abrasion resistance, and weather resistance are tested. Unqualified products are returned for reprocessing, while qualified products are considered finished products. Surface grinding uses 1000-1200 grit sandpaper to lightly grind the coating surface, removing burrs and imperfections. Compressed air is then used to blow away surface dust. Adhesion testing uses a cross-cut test, requiring an adhesion level of 0. Abrasion resistance testing uses the Taber abrasion test, with a load of 1000g and 10,000 abrasion cycles; the coating abrasion amount should be ≤0.05g. Weather resistance testing uses a xenon lamp aging test; after 1000 hours of aging, the coating should show no cracking, peeling, or significant discoloration, with a color difference ΔE ≤2.0. High and low temperature resistance testing uses a high and low temperature alternating test, maintaining -40℃ for 2 hours and 80℃ for 2 hours, cycling 100 times; the coating should show no cracking or peeling.

[0027] This invention avoids existing technical routes such as electrostatic flocking, single PE composite, single spraying, and single filler modification. It adopts an integrated process of precise substrate pretreatment + silicone-modified composite wear-resistant coating + high-voltage electrostatic spraying + gradient curing. The silicone-modified polyurethane resin is used as the base material, and is compounded with nano molybdenum disulfide, polytetrafluoroethylene micro powder, and nano alumina to form a synergistic wear-resistant system. At the same time, a special primer and crosslinking agent are introduced to form a three-layer composite structure of substrate-primer-wear-resistant coating, which achieves synergistic improvement in wear resistance, adhesion, and weather resistance, while simplifying the process and reducing costs.

[0028] Example 1

[0029] EPDM rubber was selected as the substrate for automotive sealing strips. First, surface degreasing was performed: the substrate was placed in an ultrasonic cleaning tank and cleaned for 25 minutes at 40°C and 300W ultrasonic power using a neutral degreasing agent prepared from 5 parts sodium fatty alcohol polyoxyethylene ether sulfate, 3 parts cocamidopropyl betaine, and 92 parts deionized water. Then, it was rinsed three times with deionized water and dried at 80°C until the surface was free of moisture. Next, plasma activation was performed: the degreased and dried substrate was placed in an atmospheric pressure plasma treatment device using an Ar / O2 mixed gas, with a treatment power of 150W, a treatment speed of 2m / min, a treatment distance of 5mm, and a treatment time of 60s. Finally, a primer was applied: a polyurethane primer was uniformly coated onto the plasma-activated substrate surface, with 2 parts of γ-aminopropyltriethoxysilane coupling agent added. The primer thickness was 10μm, and then pre-baked at 60°C for 15 minutes to obtain the pre-treated substrate.

[0030] The preparation of a silicone-modified composite wear-resistant coating comprises, by weight: 40 parts silicone-modified polyurethane resin, 10 parts nano molybdenum disulfide, 8 parts polytetrafluoroethylene micro powder, 3 parts γ-mercaptopropyltriethoxysilane coupling agent, 2 parts RelcaLink® series crosslinking agent, 5 parts nano alumina, 0.5 parts silicone defoamer, 0.3 parts polyether-modified polysiloxane leveling agent, and 10 parts diluent. The preparation method of the silicone-modified polyurethane resin is as follows: the polyurethane resin and silicone monomer are mixed at a weight ratio of 8:2, 0.5 parts dibutyltin dilaurate catalyst are added, the reaction is carried out at 80°C for 3 hours, and after cooling to room temperature, 1 part antioxidant 1010 is added and stirred evenly.

[0031] The prepared organosilicon-modified composite wear-resistant coating was uniformly coated on the surface of the pretreated substrate using a high-voltage electrostatic spraying process. The spraying voltage was controlled at 30kV, the spraying distance at 15cm, the spraying speed at 1m / min, and the wet film thickness of the coating was 80μm.

[0032] The coated substrate was subjected to low-temperature pre-curing (80℃, 30min), medium-temperature cross-linking curing (120℃, 60min), and high-temperature shaping curing (150℃, 20min) in sequence to obtain an automotive sealing strip with a wear-resistant coating on the surface.

[0033] The coating surface was lightly sanded with 1000-grit sandpaper to remove burrs and imperfections. Then, the surface dust was blown away with compressed air. The finished product was tested and found to have the following properties: adhesion (cross-cut test) reached level 0; abrasion resistance (Taber abrasion test, load 1000g, abrasion 10000 times) showed a coating abrasion amount of 0.045g; weather resistance (xenon lamp aging 1000h) showed no cracking, no peeling, no obvious discoloration, and a color difference ΔE=1.8; and high and low temperature resistance (-40℃ for 2h, 80℃ for 2h, 100 cycles) showed no cracking and no peeling, meeting the requirements.

[0034] Example 2

[0035] TPV elastomer was selected as the substrate for automotive sealing strips. First, surface degreasing was performed: the substrate was placed in an ultrasonic cleaning tank using a neutral degreasing agent (pH 8.0) prepared from a mixture of 6.5 parts sodium fatty alcohol polyoxyethylene ether sulfate, 4 parts cocamidopropyl betaine, and 89.5 parts deionized water. Cleaning was carried out at 45℃ and 350W ultrasonic power for 20 minutes, followed by rinsing four times with deionized water and drying at 90℃ until the surface was free of moisture. Next, plasma activation was performed: the degreased and dried substrate was placed in an atmospheric pressure plasma treatment device using an Ar / O2 mixed gas, with a treatment power of 180W, a treatment speed of 2.5m / min, a treatment distance of 6.5mm, and a treatment time of 45s. Finally, a primer was applied: a polyurethane primer was uniformly coated onto the plasma-activated substrate surface, containing 2.5 parts of γ-aminopropyltriethoxysilane coupling agent. The primer thickness was 15μm, and then pre-baked at 65℃ for 12 minutes to obtain the pre-treated substrate.

[0036] A silicone-modified composite wear-resistant coating is prepared, comprising, by weight: 50 parts silicone-modified polyurethane resin, 14 parts nano molybdenum disulfide, 12 parts polytetrafluoroethylene micro powder, 4.5 parts γ-mercaptopropyltriethoxysilane coupling agent, 3.5 parts RelcaLink® series crosslinking agent, 7.5 parts nano alumina, 1.0 part silicone defoamer, 0.5 parts polyether-modified polysiloxane leveling agent, and 15 parts diluent. The silicone-modified polyurethane resin is prepared by mixing polyurethane resin and silicone monomer at a weight ratio of 8:2, adding 0.8 parts dibutyltin dilaurate catalyst, reacting at 85°C for 2.5 h, cooling to room temperature, adding 1.5 parts antioxidant 1010, and stirring until homogeneous.

[0037] The prepared organosilicon-modified composite wear-resistant coating was uniformly coated on the surface of the pretreated substrate using a high-voltage electrostatic spraying process. The spraying voltage was controlled at 35kV, the spraying distance at 20cm, the spraying speed at 1.5m / min, and the wet film thickness of the coating was 100μm.

[0038] The coated substrate was subjected to low-temperature pre-curing (85℃, 25min), medium-temperature cross-linking curing (125℃, 50min), and high-temperature shaping curing (155℃, 18min) in sequence to obtain an automotive sealing strip with a wear-resistant coating on the surface.

[0039] The coating surface was lightly sanded with 1100-grit sandpaper to remove burrs and imperfections. Then, the surface dust was blown away with compressed air. The finished product was tested and found to have the following properties: adhesion (cross-cut test) reached level 0; abrasion resistance (Taber abrasion test, load 1000g, abrasion 10000 times) showed a coating abrasion amount of 0.038g; weather resistance (xenon lamp aging 1000h) showed no cracking, no peeling, no obvious discoloration, and a color difference ΔE=1.5; and high and low temperature resistance (-40℃ for 2h, 80℃ for 2h, 100 cycles) showed no cracking and no peeling, meeting the requirements.

[0040] Example 3

[0041] EPDM foam was selected as the substrate for automotive sealing strips. First, surface degreasing was performed: the substrate was placed in an ultrasonic cleaning tank and cleaned for 15 minutes at 50°C with a neutral degreasing agent (pH 8.5) composed of 8 parts sodium fatty alcohol polyoxyethylene ether sulfate, 5 parts cocamidopropyl betaine, and 87 parts deionized water. Then, it was rinsed 5 times with deionized water and dried at 100°C until the surface was free of moisture. Next, plasma activation was performed: the degreased and dried substrate was placed in an atmospheric pressure plasma treatment device using an Ar / O2 mixed gas, with a treatment power of 200W, a treatment speed of 3m / min, a treatment distance of 8mm, and a treatment time of 30s. Finally, a primer was applied: a polyurethane primer was uniformly coated onto the plasma-activated substrate surface, containing 3 parts of γ-aminopropyltriethoxysilane coupling agent. The primer thickness was 20μm, and then pre-baked at 70°C for 10 minutes to obtain the pre-treated substrate.

[0042] The preparation of a silicone-modified composite wear-resistant coating comprises, by weight: 60 parts silicone-modified polyurethane resin, 18 parts nano molybdenum disulfide, 15 parts polytetrafluoroethylene micro powder, 6 parts γ-mercaptopropyltriethoxysilane coupling agent, 5 parts RelcaLink® series crosslinking agent, 10 parts nano alumina, 1.5 parts silicone defoamer, 0.8 parts polyether-modified polysiloxane leveling agent, and 20 parts diluent. The preparation method of the silicone-modified polyurethane resin is as follows: the polyurethane resin and silicone monomer are mixed at a weight ratio of 8:2, 1 part dibutyltin dilaurate catalyst is added, the reaction is carried out at 90°C for 2 hours, and after cooling to room temperature, 2 parts antioxidant 1010 are added and stirred evenly.

[0043] The prepared organosilicon-modified composite wear-resistant coating was uniformly coated on the surface of the pretreated substrate using a high-voltage electrostatic spraying process. The spraying voltage was controlled at 40kV, the spraying distance at 25cm, the spraying speed at 2m / min, and the wet film thickness of the coating was 120μm.

[0044] The coated substrate was subjected to low-temperature pre-curing (90℃, 20min), medium-temperature cross-linking curing (130℃, 40min), and high-temperature shaping curing (160℃, 15min) in sequence to obtain an automotive sealing strip with a wear-resistant coating on the surface.

[0045] The coating surface was lightly sanded with 1200-grit sandpaper to remove burrs and imperfections. Then, the surface dust was blown away with compressed air. The finished product was tested and found to have the following properties: adhesion (cross-cut test) reached level 0; abrasion resistance (Taber abrasion test, load 1000g, abrasion 10000 times) showed a coating abrasion amount of 0.032g; weather resistance (xenon lamp aging 1000h) showed no cracking, no peeling, no obvious discoloration, and a color difference ΔE=1.2; and high and low temperature resistance (-40℃ for 2h, 80℃ for 2h, 100 cycles) showed no cracking and no peeling, meeting the requirements.

[0046] Comparative Example 1

[0047] The same TPV elastomer substrate as in Example 2 was selected and treated using the existing electrostatic flocking process: after degreasing the substrate, an adhesive was applied, and the substrate was passed through an electrostatic flocking box. The charged flock was implanted into the adhesive layer under the action of an electrostatic field, and then dried and cured. The finished product was tested. The adhesion (cross-cut test) was level 2. The abrasion resistance (Taber abrasion test, load 1000g, abrasion 10000 times) showed a coating abrasion amount of 0.18g. The weather resistance (xenon lamp aging 1000h) showed flock detachment, surface yellowing, and color difference ΔE=3.8. The high and low temperature resistance (-40℃ for 2h, 80℃ for 2h, 100 cycles) showed flock detachment and coating peeling. The performance was far lower than that of Example 2 of this invention.

[0048] Comparative Example 2

[0049] The same TPV elastomer substrate as in Example 2 was selected and processed using existing PE composite technology: high-density polyethylene was extruded into a sheet film through a special mold, bonded and laminated with the substrate, cooled and shaped, and the finished product was tested. The adhesion (cross-cut test) was grade 1. The abrasion resistance (Taber abrasion test, load 1000g, abrasion 10000 times) showed a coating abrasion amount of 0.12g, with obvious bumps and scratches on the surface. The weather resistance (xenon lamp aging 1000h) showed PE layer peeling and obvious color difference, with a color difference ΔE=3.2. The high and low temperature resistance (-40℃ for 2h, 80℃ for 2h, 100 cycles) showed PE layer cracking. The performance was lower than that of Example 2 of this invention.

[0050] Comparative Example 3

[0051] The same TPV elastomer substrate as in Example 2 was selected and treated using the existing single polyurethane spraying process: after degreasing the substrate, a polyurethane coating was directly sprayed and cured at a single temperature (120°C). The finished product was tested, and the adhesion (cross-cut test) was grade 1. The abrasion resistance (Taber abrasion test, load 1000g, abrasion 10000 times) showed a coating abrasion amount of 0.08g. The weather resistance (xenon lamp aging for 1000h) showed coating cracking and slight peeling, with a color difference ΔE=2.8. The high and low temperature resistance (holding at -40°C for 2h, holding at 80°C for 2h, 100 cycles) showed coating cracking. The performance was lower than that of Example 2 of this invention.

[0052] As can be seen from the comparison between the above embodiments and comparative examples, the present invention is significantly superior to the prior art in terms of adhesion, wear resistance, weather resistance, and high and low temperature resistance.

[0053] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A method for treating the surface of an automotive sealing strip with a wear-resistant coating, characterized in that, Includes the following steps: S1. Select automotive sealing strip substrate, and sequentially perform surface degreasing, plasma activation, and primer treatment to obtain pretreated substrate; S2. Preparation of organosilicon-modified composite wear-resistant coatings; S3. The prepared organosilicon-modified composite wear-resistant coating is uniformly coated on the surface of the pretreated substrate; S4. The coated substrate is subjected to low-temperature pre-curing, medium-temperature cross-linking curing, and high-temperature shaping curing in sequence to obtain an automotive sealing strip with a wear-resistant coating on the surface. The low-temperature pre-curing temperature is set to 80-90℃ and the time is set to 20-30min. The medium-temperature cross-linking curing temperature is set to 120-130℃ and the time is set to 40-60min. The high-temperature shaping curing temperature is set to 150-160℃ and the time is set to 15-20min. S5. After curing, the sealing strip is surface-polished and dust-removed. Then, the coating adhesion, wear resistance, and weather resistance are tested. Unqualified products are returned for reprocessing, and qualified products are the finished products.

2. The method for treating the surface of an automotive sealing strip with a wear-resistant coating according to claim 1, characterized in that: In S1, the surface degreasing process involves placing the sealing strip substrate in an ultrasonic cleaning tank, using a neutral degreasing agent, and cleaning for 15-25 minutes at a temperature of 40-50℃ and an ultrasonic power of 300-400W. Then, it is rinsed 3-5 times with deionized water and dried at 80-100℃ until the surface is free of moisture. The neutral degreasing agent is prepared by mixing 5-8 parts of sodium fatty alcohol polyoxyethylene ether sulfate, 3-5 parts of cocamidopropyl betaine, and 87-92 parts of deionized water.

3. The method for treating the surface of an automotive sealing strip with a wear-resistant coating according to claim 1, characterized in that: In S1, plasma activation specifically involves placing the degreased and dried substrate into an atmospheric pressure plasma treatment device, using an Ar / O2 mixed gas, and controlling the treatment power to be 150-200W, the treatment speed to be 2-3m / min, the treatment distance to be 5-8mm, and the treatment time to be 30-60s.

4. The method for treating the surface of an automotive sealing strip with a wear-resistant coating according to any one of claims 1-3, characterized in that: In S1, the primer treatment specifically involves uniformly coating a primer layer onto the plasma-activated substrate surface. The thickness of the primer layer is set to 10-20 μm, and then pre-baking at 60-70℃ for 10-15 min.

5. The method for treating the surface of an automotive sealing strip with a wear-resistant coating according to claim 1, characterized in that: S2 silicone-modified composite wear-resistant coating includes 40-60 parts silicone-modified polyurethane resin, 10-18 parts nano molybdenum disulfide, 8-15 parts polytetrafluoroethylene micro powder, 3-6 parts γ-mercaptopropyltriethoxysilane coupling agent, 2-5 parts crosslinking agent, 5-10 parts nano alumina, 0.5-1.5 parts defoamer, 0.3-0.8 parts leveling agent, and 10-20 parts diluent.

6. The method for treating the surface of an automotive sealing strip with a wear-resistant coating according to claim 5, characterized in that: Organosilicon-modified polyurethane resin is prepared by mixing polyurethane resin and organosilicon monomers at a weight ratio of 8:2, adding 0.5-1 part of dibutyltin dilaurate catalyst, reacting at 80-90℃ for 2-3 hours, cooling to room temperature, adding 1-2 parts of antioxidant 1010, and stirring evenly.

7. The method for treating the surface of an automotive sealing strip with a wear-resistant coating according to claim 1, characterized in that: In S3, a high-voltage electrostatic spraying process is used to coat the surface of the pretreated substrate with an organosilicon-modified composite wear-resistant coating. The spraying voltage is set to 30-40kV, the spraying distance is set to 15-25cm, and the spraying speed is set to 1-2m / min.

8. The method for treating the surface of an automotive sealing strip with a wear-resistant coating according to claim 1 or 7, characterized in that: The wet film thickness of the silicone-modified composite wear-resistant coating in S3 applied to the pretreated substrate surface is set to 80-120 μm.

9. The method for treating the surface of an automotive sealing strip with a wear-resistant coating according to claim 1, characterized in that: In S5, the coating surface is sanded with 1000-1200 grit sandpaper, and then the surface dust is blown away with compressed air.