Two-component large-particle sealing strip coating and preparation method thereof

Abstract

The invention discloses a two-component large-particle sealing strip coating and a preparation method thereof. The two-component large-particle sealing strip coating comprises the following components in percentage by mass: 20-40% of waterborne polycarbonate polyurethane; 0.5%-1% of a defoaming agent; 1%-2% of a dispersant; 1%-2% of a wetting agent; 1%-3% of carbon black slurry; 2%-4% of wear-resistant powder; 3%-7% of large-particle powder; 0%-2% of matting powder; 1%-5% of a wear-resistant auxiliary agent; 5%-10% of a polytetrafluoroethylene aqueous emulsion; 5%-15% of a water-based organic silicon emulsion; 5%-10% of water-based chlorinated polyolefin; 0%-2% of a thickening agent; 0.2%-0.5% of an anti-settling agent; 5%-10% of an alcohol ether auxiliary agent; and 5%-20% of deionized water. The wear resistance of the sealing strip can be improved, and the characteristic of low friction coefficient of the particle coating is combined, so that abnormal sound generated by friction between opening and closing door glass and the sealing strip and abnormal sound generated by friction between the sealing strip and a metal plate when an automobile runs on a twisted road are reduced.

Description

Technical Field

[0001] The present invention relates to a sealing strip coating and a preparation method thereof, in particular to a two-component large-particle sealing strip coating and a preparation method thereof. Background Art

[0002] With the introduction of frameless door models of cars such as Volkswagen and Audi into China, coupled with the booming development of the electric vehicle industry, frameless door models have been favored by domestic automotive engineers due to their stylish and dynamic appearance and wider driver's field of vision. Mainstream domestic automobile manufacturers have launched a number of frameless door models.

[0003] The opening and closing system of frameless doors automatically lowers the glass by 0.5-1 cm when the door is opened and automatically rises to engage the sealing strip when the door is closed. The sealing strip is mounted on the vehicle body, and the glass frequently rubs against it. Therefore, the requirements for the sealing strip on the vehicle body are much higher than those on traditional framed doors. Because smooth sealing strip coatings have a large contact area and high friction resistance, they are prone to wear. This is why large-particle sealing strip coatings have emerged. Large-particle sealing strip coatings reduce the contact area, resulting in a low coefficient of friction, high wear resistance, and significant noise reduction. Therefore, they are widely used in frameless door models.

[0004] Currently, the granular coatings used in automotive plants are imported. Not only are the product range limited and expensive, but they also lack wear and noise resistance. Therefore, improving the wear resistance and service life of granular seals, while also reducing noise, has become a key focus for seal system engineers. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a two-component large-particle sealing strip coating, which can improve the wear resistance of the sealing strip, and combine the low friction coefficient characteristics of the particle coating to reduce the abnormal noise caused by friction between the door glass and the sealing strip when opening and closing, and the abnormal noise caused by friction between the sealing strip and the sheet metal when the car is driving on a twisted road.

[0006] The technical solution adopted by the present invention to solve the above technical problems is to provide a two-component large-particle sealing strip coating, which comprises the following components by mass percentage: Waterborne polycarbonate polyurethane 20%-40%; Defoaming agent 0.5%-1%; Dispersant 1%-2%; Wetting agent 1%-2%; Carbon black slurry 1%-3%; Wear-resistant powder 2%-4%; Large particle powder 3%-7%; Matting powder 0%-2%; Wear-resistant additives 1%-5%; Polytetrafluoroethylene aqueous emulsion 5% -10%; Water-based silicone emulsion 5%-15%; Water-based chlorinated polyolefin 5% -10%; Thickener 0%-2%; Anti-settling agent 0.2%-0.5%; Alcohol ether additives 5%-10%; Deionized water 5%-20%.

[0007] Furthermore, the waterborne polycarbonate polyurethane has an elongation at break of 100-300%, a tensile strength greater than 30 MPa, and a solid content greater than or equal to 35%.

[0008] Furthermore, the wear-resistant powder is high-density polyethylene or polyamide, and has an average particle size of 10 μm.

[0009] Furthermore, the large particle powder is high-density polyethylene, polypropylene or polyamide, and the average particle size is 60um, 80um, 100um or a mixture of the above powders with different average particle sizes.

[0010] Furthermore, the matting powder is silicon dioxide matting powder.

[0011] Furthermore, the aqueous silicone emulsion is a non-ionic emulsion, and its terminal groups are hydroxyl groups or amino groups.

[0012] Furthermore, the thickener is a polyurethane associative thickener, the hydrophobic end of the molecule is associated with the hydrophobic structure of latex particles, surfactants and pigments, and the viscosity is 50-200 cps at room temperature.

[0013] Furthermore, the anti-settling agent is a modified urea solution.

[0014] In order to solve the above technical problems, the present invention also provides a preparation method of the above-mentioned two-component large-particle sealing strip coating, comprising the following steps: S1) mixing part of water-based polycarbonate polyurethane, carbon black slurry, part of defoaming agent, part of dispersant, part of wetting agent, wear-resistant powder, large-particle powder, part of deionized water and alcohol ether cosolvent in sequence, stirring and pre-dispersing, and then adding to a sand mill and grinding evenly; S2) adding the remaining water-based polyurethane emulsion and defoaming agent, dispersant, and wetting agent in sequence to a reactor and stirring evenly, adding the ground and dispersed raw materials in proportion, and then adding matting powder and stirring and dispersing at high speed; S3) adding a wear-resistant additive, polytetrafluoroethylene aqueous emulsion, water-based silicone emulsion, and water-based chlorinated polyolefin to the reactor in sequence and stirring evenly, and then adjusting the solid content of the finished product with cosolvent and deionized water; S4) adding a thickener to adjust the viscosity of the coating to an appropriate range, and then adding an anti-settling additive and stirring evenly.

[0015] Furthermore, in step S1, the stirring speed is 600-800 rpm, and the premix is stirred for 30 minutes; in step S2, the stirring speed is 1200-1500 rpm, and high-speed dispersion is performed for 30-40 minutes; in step S3, the stirring speed is adjusted to 800-1000 rpm for 30-40 minutes; and in step S4, stirring is performed for 10-15 minutes.

[0016] Compared with the prior art, the present invention has the following beneficial effects: the two-component large-particle sealing strip coating provided by the present invention realizes the localization of large-particle sealing strip coatings that can be used for frameless door sealing strips. When used, a certain proportion of isocyanate or carbodiimide curing agent is added, so that it can be sprayed after online rubber extrusion, or sprayed on corners or special-shaped parts offline. Due to the addition of wear-resistant additives, wear-resistant powders and coarse-particle powders, the wear resistance of automobile sealing strips can be effectively increased, which plays a positive role in improving the service life of automobile sealing strips and the comfort of riding; the use of water-based polycarbonate polyurethane resin as the main resin enhances the wear resistance and weather resistance of the sealing strip coating; the added silicone emulsion and polytetrafluoroethylene aqueous emulsion enhance the smoothness of the sealing strip coating and reduce the friction coefficient of the coating, thereby reducing the occurrence of abnormal noise; by adding thickeners and anti-settling agents, particle sedimentation can be reduced and the storage stability of the coating can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart for preparing the two-component large-particle sealing strip coating of the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below with reference to the accompanying drawings and examples.

[0019] The two-component large-particle sealing strip coating provided by the present invention comprises the following components by mass percentage: Waterborne polycarbonate polyurethane 20%-40%; Defoaming agent 0.5%-1%; Dispersant 1%-2%; Wetting agent 1%-2%; Carbon black slurry 1%-3%; Wear-resistant powder 2%-4%; Large particle powder 3%-7%; Matting powder 0%-2%; Wear-resistant additives 1%-5%; Polytetrafluoroethylene aqueous emulsion 5% -10%; Water-based silicone emulsion 5%-15%; Water-based chlorinated polyolefin 5% -10%; Thickener 0%-2%; Anti-settling agent 0.2%-0.5%; Alcohol ether additives 5%-10%; Deionized water 5%-20%.

[0020] The two-component large-particle weatherstrip coating provided by the present invention can be composed of one or more water-based polycarbonate polyurethanes, requiring high mechanical stability and the ability to be grinded and dispersed. The water-based polycarbonate polyurethane is required to have an elongation at break of 100-300%, a tensile strength greater than 30 MPa, and a solids content greater than or equal to 35%. This prevents excessive large-particle powder content, which can lead to poor coating of large particles, or insufficient toughness in the coating, which can easily cause particles to fall off due to scratches.

[0021] The present invention provides a two-component large-particle sealing strip coating, wherein the wear-resistant powder has an average particle size of 10 μm and is made of high-density polyethylene (HDPE) or polyamide, etc. The more the amount added is within the range of 2-4%, the better the wear resistance of the coating.

[0022] The two-component large-particle sealing strip coating provided by the present invention can have an average particle size of 60 μm, 80 μm, or 100 μm, or a mixture of these different average particle sizes. The material can be high-density polyethylene, polypropylene, or polyamide, and the specific particle size is selected based on the desired roughness and granularity. The larger the particle size, the smaller the amount added. The total amount of powder added should not exceed 7%. Otherwise, due to excessive particle content and the dry film thickness at the application end of the coating being lower than the large particle size, the particle coating may be poorly coated and easily fall off.

[0023] In the two-component large-particle sealing strip coating provided by the present invention, the matting agent is silicon dioxide produced by an organic treatment precipitation method, and can be Evonik Degussa OK520, OK607, TS-100, etc. The specific addition amount is determined according to the required gloss of the finished product. The more matting agent is added, the lower the gloss.

[0024] The two-component large-particle sealing strip coating provided by the present invention comprises a water-based silicone emulsion which is a non-ionic emulsion, is stable with polyurethane or acrylate, has a terminal group of hydroxyl or amino, and can react with an isocyanate curing agent for cross-linking under high temperature conditions, thereby improving the flexibility and smoothness of the coating.

[0025] The present invention provides a two-component large-particle sealing strip coating, wherein the thickener is a polyurethane associative thickener, and the hydrophobic end of the molecule associates with hydrophobic structures such as latex particles, surfactants, and pigments to form a three-dimensional network structure. The viscosity of the coating can be adjusted to vary within the range of 50-200 cps at room temperature. Too high a viscosity is not conducive to continuous spraying applications on site.

[0026] The present invention provides a two-component, large-particle sealing strip coating, wherein the anti-settling agent is a modified urea solution, added in an amount of 0.2-0.5%. After stirring and adding to the water-based coating, the additive forms a three-dimensional network structure, which produces thixotropic flow properties, preventing powders or pigments from settling, improving anti-sagging properties, and ensuring spray stability. If the addition amount is less than 0.2%, wear-resistant powders, granular powders, and matting agents in the coating are more likely to settle due to their high specific gravity, resulting in insufficient stability. If the addition amount is greater than 0.5%, the thixotropic properties are increased, the coating viscosity deteriorates, and the fluidity deteriorates, making it difficult to apply the coating continuously on-site.

[0027] The two-component large-particle sealing strip coating provided by the present invention not only improves the wear resistance of the automotive sealing strip coating by adding wear-resistant powder, large-particle powder, silicone emulsion, and polytetrafluoroethylene aqueous emulsion, but also reduces the coating's low friction coefficient by reducing contact area. The combination of polytetrafluoroethylene aqueous emulsion and silicone resin increases the coating's smoothness, significantly reducing the noise caused by friction between the sealing strip when the window is raised or lowered, and the noise caused by friction between the sealing strip and sheet metal when the car is driving on twisted roads, thereby increasing the service life and comfort of the automotive sealing strip. The addition of a thickener and an anti-settling agent ensures particle stability and spray continuity in the coating under low viscosity conditions, thereby improving the coating's stability and application range.

[0028] See Figure 1 The present invention also provides a method for preparing a two-component large-particle sealing strip coating, which comprises the following steps in sequence: a) Mix and stir part of water-based polycarbonate polyurethane, carbon black slurry, part of defoamer, dispersant, wetting agent, wear-resistant powder, large particle powder, part of deionized water and alcohol ether additives in order to pre-disperse and mix, then grind into a sand mill until uniform; b) Add the remaining water-based polycarbonate polyurethane, defoamer, dispersant, and wetting agent to the reactor in sequence, stir evenly, then add the ground and dispersed raw materials in proportion, then add the matting powder, and stir and disperse at high speed; c) adding the wear-resistant additive, polytetrafluoroethylene aqueous emulsion, aqueous silicone emulsion, and aqueous chlorinated polyolefin to the reaction kettle in sequence and stirring evenly, and then adjusting the solid content of the finished product with an alcohol ether additive and deionized water; d) Add thickener to adjust the coating viscosity to the appropriate range, then add anti-settling agent and stir evenly; e) Filling after filtration.

[0029] The present invention provides a method for preparing a two-component large-particle sealing strip coating, wherein, in step a), part of the resin, part of the defoamer, part of the dispersant, and part of the wetting agent are linearly added with stirring at a stirring speed of 600-800 rpm, and then wear-resistant powder, large-particle powder, part of the deionized water, and alcohol ether additives are added, the premix is stirred for 20-30 minutes, and then added to a grinder and ground for 40-60 minutes for uniform use; in step b), the remaining resin and additives are evenly dispersed, and the stirring speed is increased to 1200-1500 rpm. Add the required matting powder and the grinding slurry from step a in proportion, and disperse at high speed for 30-40 minutes. After completing step c), adjust the stirring speed to 800-1000 rpm, sequentially add a defoamer, a wear-resistant additive, a polytetrafluoroethylene aqueous emulsion, a water-based silicone emulsion, and a water-based chlorinated polyolefin, and then add a cosolvent and deionized water to adjust the solids content. The process continues for 30-40 minutes. In step d), add an anti-settling agent and a thickener, adjust the coating viscosity to 50-200 cps, and stir for 10-30 minutes. Finally, in step e), filter through a double-layer 50-mesh filter cloth or bag and package the mixture to obtain the finished coating.

[0030] A specific embodiment is given below: 330 kg of water-based polycarbonate polyurethane resin was added to the feeding kettle, followed by 3.3 kg of defoaming agent, 11 kg of dispersant, and 11 kg of wetting agent. The stirring speed was 600-700 rpm, and then 44 kg of wear-resistant powder, 44 kg of large-particle powder, 33 kg of alcohol ether solvent, and 55 kg of deionized water were added. The premixing time was 20-25 min, and then the mixture was transferred to a sand mill and ground for 40-50 min to obtain a uniformly ground slurry for use.

[0031] In a 1-ton feeding kettle, add 100kg of water-based polycarbonate polyurethane resin, grind 483kg of uniform slurry, start stirring to a speed of 1300-1500 rpm, add 3kg of defoaming agent, stir for 10 minutes, add 10kg of matting powder, rinse the sticky powder with 10kg of deionized water and put it into the feeding kettle, and disperse it for 30-40 minutes.

[0032] Reduce the stirring speed to 800-1000 rpm, then add 20 kg of wear-resistant additive, 20 kg of carbon black slurry, 100 kg of polytetrafluoroethylene aqueous emulsion, 100 kg of water-based silicone emulsion, and 70 kg of water-based chlorinated polyolefin in sequence, add 20 kg of alcohol ether solvent and 50 kg of deionized water to adjust the solid content of the product, and the stirring time is 30-40 min in total.

[0033] Add 10kg thickener and 4kg anti-settling agent, and stir for 15-20 minutes; Finally, filter with 50-mesh filter cloth and package, and the obtained finished coating product is about 1000 kg.

[0034] The large particle sealing strip coating prepared in the embodiment and an imported sealing strip coating were subjected to an accelerated storage test at 50°C. The results are shown in Table 1.

[0035] In the application, the product of this invention creates a rough tactile feel through large particles. Abrasion-resistant powder, silicone emulsion, and polytetrafluoroethylene emulsion enhance the coating's wear resistance and reduce the coefficient of friction (to between 0.1 and 0.2). This eliminates the creaking noise caused by the seal strip rubbing against the glass or metal sheet during vehicle window raising and lowering, improving comfort. During use, the addition of a corresponding isocyanate or carbodiimide curing agent enhances the coating's physical properties and durability, improving its performance under various operating conditions (e.g., extrusion spraying with high-temperature baking for seal strips, and offline spraying with low-temperature baking for seal strips).

[0036] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A two-component large particle sealing strip coating, characterized in that: Contains the following components by mass percentage: Waterborne polycarbonate polyurethane 20%-40%; Defoaming agent 0.5%-1%; Dispersant 1%-2%; Wetting agent 1%-2%; Carbon black slurry 1%-3%; Wear-resistant powder 2%-4%; Large particle powder 3%-7%; Matting powder 0%-2%; Wear-resistant additives 1%-5%; Polytetrafluoroethylene aqueous emulsion 5% -10%; Water-based silicone emulsion 5%-15%; Water-based chlorinated polyolefin 5% -10%; Thickener 0%-2%; Anti-settling agent 0.2%-0.5%; Alcohol ether additives 5%-10%; Deionized water 5%-20%.

2. The two-component large-particle sealing strip coating according to claim 1, characterized in that: The waterborne polycarbonate polyurethane has an elongation at break of 100-300%, a tensile strength greater than 30 MPa, and a solid content greater than or equal to 35%.

3. The two-component large-particle sealing strip coating according to claim 1, characterized in that: The wear-resistant powder is high-density polyethylene or polyamide, and has an average particle size of 10 μm.

4. The two-component large-particle sealing strip coating according to claim 1, characterized in that: The large particle powder is high-density polyethylene, polypropylene or polyamide, and has an average particle size of 60um, 80um, 100um or a mixture of the above powders with different average particle sizes.

5. The two-component large-particle sealing strip coating according to claim 1, characterized in that: The matting powder is silicon dioxide matting powder.

6. The two-component large-particle sealing strip coating according to claim 1, characterized in that: The aqueous organic silicon emulsion is a non-ionic emulsion, and its terminal groups are hydroxyl groups or amino groups.

7. The two-component large particle sealing strip coating according to claim 1, characterized in that: The thickener is a polyurethane associative thickener, the hydrophobic end of the molecule is associated with the hydrophobic structure of latex particles, surfactants and pigments, and the viscosity is 50-200 cps at room temperature.

8. The two-component large particle sealing strip coating according to claim 1, characterized in that: The anti-settling agent is a modified urea solution.

9. A method for preparing a two-component large-particle sealing strip coating according to any one of claims 1 to 8, characterized in that: The steps include: S1) sequentially mixing and pre-dispersing a portion of waterborne polycarbonate polyurethane, carbon black slurry, a portion of defoamer, a portion of dispersant, a portion of wetting agent, wear-resistant powder, large particle powder, a portion of deionized water and alcohol ether cosolvent, and then adding the mixture to a sand mill and grinding evenly; S2) adding the remaining aqueous polyurethane emulsion, defoamer, dispersant, and wetting agent to a reactor in sequence, stirring evenly, then adding the ground and dispersed raw materials in proportion, and then adding the matting powder, stirring and dispersing at high speed; S3) adding the wear-resistant additive, polytetrafluoroethylene aqueous emulsion, aqueous silicone emulsion, and aqueous chlorinated polyolefin to a reaction kettle in sequence and stirring evenly, and then adjusting the solid content of the finished product with a cosolvent and deionized water; S4) Add thickener to adjust the coating viscosity to the appropriate range, then add anti-settling agent and stir evenly.

10. The method for preparing a two-component large-particle sealing strip coating according to claim 9, characterized in that: In step S1, the stirring speed is 600-800 rpm, and the premix is stirred for 30 minutes; in step S2, the stirring speed is 1200-1500 rpm, and high-speed dispersion is performed for 30-40 minutes; in step S3, the stirring speed is adjusted to 800-1000 rpm for 30-40 minutes; and in step S4, stirring is performed for 10-15 minutes.

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