Composite polyurethane emulsion, skin material and corresponding preparation method

Abstract

The application relates to the field of high polymer materials, and discloses a composite polyurethane emulsion, a skin material and corresponding preparation methods. The preparation method of the composite polyurethane emulsion comprises the following steps: preparing a SiO2 water dispersion; pre-hydrolyzing fibers in lye to obtain a fiber dispersion; mixing the SiO2 water dispersion and the fiber dispersion, stirring and post-treating to obtain fibrillated fibers; wrapping a polyurethane coating on the surface of the fibrillated fibers to obtain wrapped fibers; and adding the wrapped fibers, the SiO2 water dispersion and other additives into a water-based polyurethane emulsion and stirring to obtain the composite polyurethane emulsion. The application can improve the wear resistance and self-cleaning performance of the skin material.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a composite polyurethane emulsion, a wear-resistant skin material with self-cleaning function, and a corresponding preparation method. Background Technology

[0002] Carpets are an important component of automotive interiors, providing functions such as slip resistance, stain resistance, aesthetics, and shock absorption. Traditional plastic carpets easily attract dust and stains, resulting in high cleaning and maintenance costs. Existing technologies sometimes improve stain resistance by forming a surface coating on the carpet layer, but these coatings are prone to wear and tear over time.

[0003] Patent CN120039002A discloses a colorful TPO interior floor mat surface and its preparation method. The colorful TPO interior floor mat surface, from the outside to the inside, consists of a surface functional layer, a colorful pattern layer, a substrate layer, and a bottom layer structure. The surface functional layer is used to improve wear resistance. The components of the surface functional layer, by weight, include 40-80 parts of matte waterborne PUD resin, 5-20 parts of matte waterborne PUA resin, 1-10 parts of wear-resistant additive, 5-8 parts of crosslinking agent, and 0-30 parts of diluent. The wear-resistant additive is an ultra-high molecular weight polysiloxane dispersion. While the surface functional layer in this patent improves wear resistance, it does not enhance self-cleaning properties.

[0004] Therefore, it is necessary to develop a skin material that combines wear resistance and self-cleaning properties, as well as a coating for forming the corresponding coating in the skin. Summary of the Invention

[0005] The main objective of this invention is to provide a composite polyurethane emulsion, a wear-resistant skin material with self-cleaning function, and a corresponding preparation method, so as to solve the technical problem of how to improve the wear resistance and self-cleaning performance of the skin material.

[0006] According to one aspect of the present invention, a method for preparing a composite polyurethane emulsion is provided, comprising the following steps: S11, preparing a SiO2 aqueous dispersion; S12, pre-hydrolyzing fibers in an alkaline solution to obtain a fiber dispersion; S13, mixing the SiO2 aqueous dispersion and the fiber dispersion and performing stirring and post-treatment to obtain fibrillated fibers; S14, coating the surface of the fibrillated fibers with a polyurethane coating to obtain coated fibers; S15, adding the coated fibers, the SiO2 aqueous dispersion, and other additives to an aqueous polyurethane emulsion and stirring to obtain a composite polyurethane emulsion.

[0007] According to one embodiment of the present invention, step S11 includes: mixing SiO2 powder with a particle size of 5~10μm with water at a mass ratio of 1:(3~7) and stirring at a speed of 1500~2500rpm, and then adding silane coupling agent and stirring at a speed of 400~600rpm.

[0008] According to an embodiment of the present invention, step S12 includes: adding fiber and dispersant to an alkaline solution with a mass concentration of 5-30%, stirring at 100-200 rpm for 1-2 hours at 80-120°C to obtain a fiber dispersion, wherein the mass ratio of fiber to alkaline solution is 1:(30-50); in step S12, the fiber is a hyperbranched fiber modified by a branching agent.

[0009] According to one embodiment of the present invention, in step S13, the mass ratio of SiO2 aqueous dispersion to fiber dispersion is 1:(10~20); stirring includes stirring at a speed of 5000~20000 rpm for 10~20 min; post-treatment includes washing with water multiple times and then drying.

[0010] According to one embodiment of the present invention, step S14 includes: immersing the fibrillated fibers in an aqueous polyurethane emulsion with a mass concentration of 1-5%, and then drying them.

[0011] According to one embodiment of the present invention, step S15 includes: adding the wrapped fiber and SiO2 aqueous dispersion to the aqueous polyurethane emulsion, stirring at a speed of 400-600 rpm for 5-15 min, and then adding other additives and continuing to stir for 20-40 min; in step S15, the mass ratio of the wrapped fiber to the aqueous polyurethane emulsion is 1:(50-100), and the mass ratio of the SiO2 aqueous dispersion to the aqueous polyurethane emulsion is 1:(10-20).

[0012] According to another aspect of the present invention, a composite polyurethane emulsion is provided, which is prepared by the method described above.

[0013] According to another aspect of the present invention, a method for preparing a wear-resistant skin material with self-cleaning function is provided, comprising the following steps: S21, preparing a substrate layer; S22, forming a pattern layer on the surface of the substrate layer; S23, coating the above-mentioned composite polyurethane emulsion onto the surface of the substrate layer on which the pattern layer is formed, to form a wear-resistant layer.

[0014] According to one embodiment of the present invention, in step S21, a substrate layer is prepared using a mixture comprising a thermoplastic material and a polyurethane graft modifier, wherein the mass of the polyurethane graft modifier is 1 to 10% of the mass of the thermoplastic material.

[0015] According to another aspect of the present invention, a wear-resistant skin material with self-cleaning function is provided, which is prepared by the method described above.

[0016] In the technical solution of this invention, the fiber is first pre-hydrolyzed to improve its accessibility and reactivity, thereby promoting the subsequent fibrillation process and improving fibrillation efficiency. Then, an aqueous dispersion of SiO2 and a fiber dispersion are mixed and fibrillated. SiO2 assists in the efficient dispersion of the fiber and prevents it from re-agglomerating, making the fibrillation process more efficient and controllable. Next, a polyurethane coating is applied to fix the planar branched structure of the fibrillated fiber, ensuring that the fiber no longer splits. This also allows for rapid reaction during subsequent processing, improving compatibility and ease of processing. Finally, the coated fiber, SiO2 aqueous dispersion, and other additives are added to an aqueous polyurethane emulsion and stirred to obtain a composite polyurethane emulsion. In the coating formed by this emulsion, the planar branched fiber structure and SiO2 form a micron-sized hill-like uneven surface, which improves the matte effect of the coating, enhances surface feel and dirt resistance. Simultaneously, the network structure formed by the fiber and the reinforcing points formed by the SiO2 particles work synergistically to improve the coating's abrasion resistance. Therefore, the coating prepared using the composite polyurethane emulsion of the present invention can effectively improve self-cleaning performance and wear resistance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a method for preparing a composite polyurethane emulsion according to an embodiment of the present invention is shown;

[0019] Figure 2 A flowchart illustrating a method for preparing a wear-resistant skin material with self-cleaning function according to an embodiment of the present invention is shown. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0021] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0022] refer to Figure 1 This invention proposes a method for preparing a composite polyurethane emulsion, comprising the following steps:

[0023] S11, prepare SiO2 aqueous dispersion;

[0024] S12 causes the fiber to undergo pre-hydrolysis in an alkaline solution to obtain a fiber dispersion.

[0025] S13, SiO2 aqueous dispersion and fiber dispersion are mixed and stirred and post-treated to obtain fibrillated fibers;

[0026] S14, a polyurethane coating is applied to the surface of fibrillated fibers to obtain coated fibers;

[0027] S15, the wrapped fibers, SiO2 aqueous dispersion and other additives are added to the aqueous polyurethane emulsion and stirred to obtain a composite polyurethane emulsion.

[0028] The SiO2 aqueous dispersion prepared in step S11 is used in steps S13 and S15.

[0029] In step S12, the fiber undergoes pre-hydrolysis in an alkaline solution. This effectively reduces the fiber's structural compactness and rigidity through chemical and physical processes, improving its accessibility and reactivity, thereby significantly promoting the subsequent fibrillation process and increasing fibrillation efficiency. Pre-hydrolysis also ensures the fiber surface possesses sufficient reactive groups, enabling it to form cross-linked structures with polyurethane emulsions and other additives such as curing agents, significantly enhancing the coating's mechanical properties.

[0030] In step S13, fibrillation is performed to obtain fibrillated fibers. Fibrillation refers to the splitting of the fiber surface into fine microfibers. The fibrillated fibers consist of a fiber body and microfibers. The microfibers are peeled from the surface of the fiber body and extend from it. Fibrillation can be induced by applying mechanical force through stirring. The pre-hydrolysis process in step S12 makes fibrillation easier and more efficient. This invention performs fibrillation in the presence of SiO2 particles. SiO2 particles can assist in the efficient dispersion of fibers and prevent them from re-aggregating, making fibrillation more efficient and controllable. Specifically, SiO2 particles can be adsorbed and deposited on the large specific surface area generated by fibrillation, and some may enter the gaps between fibers, essentially "grafting" or "anchoring" rigid particles to the fiber surface. The presence of particles may act as physical spacers, preventing the fibrillated microfibers from re-aggregating tightly in subsequent processes, helping to maintain the loose network structure after fiber opening. The inherent properties of the fiber (e.g., surface energy, roughness, chemical properties) may also be altered due to the SiO2 modification of its surface.

[0031] In step S14, by coating with polyurethane, the planar branched structure of the fibrillated fibers can be fixed, ensuring that the fibers no longer split. At the same time, it can also enable the fibers to react quickly in subsequent processing, improving compatibility and processing convenience.

[0032] In step S15, the wrapped fibers, SiO2 aqueous dispersion, and other additives are added to the aqueous polyurethane emulsion and stirred to obtain a composite polyurethane emulsion. In the final composite polyurethane emulsion, the SiO2 particles from step S13 may be adsorbed on the fiber surface and fill the gaps between the fibers, and may also be entangled by the fibers. The SiO2 particles from step S15 can be uniformly dispersed in the emulsion. In the coating formed by the composite polyurethane emulsion, the self-cleaning performance and wear resistance of the coating can be effectively improved through the synergistic effect of the fibrillated fibers and SiO2 particles. Specifically, the planar branched structure of the fibers and the SiO2 form a micron-sized hill-like uneven surface, which can improve the matte effect of the coating, enhance the surface feel and dirt resistance. The mesh structure formed by the fibers can effectively absorb and disperse impact energy and inhibit crack propagation, while the reinforcing points formed by the SiO2 particles can resist micro-scratches and hinder cracking. The synergistic effect of both improves the wear resistance of the coating.

[0033] In some embodiments, step S11 includes: mixing SiO2 powder with a particle size of 5-10 μm with water at a mass ratio of 1:(3-7) and stirring at 1500-2500 rpm for 20-40 min; then adding a silane coupling agent and stirring at 400-600 rpm for 5-15 min. The mass of the silane coupling agent can be 3-5% of the mass of the SiO2 powder. The SiO2 powder can have a high degree of structure to improve dispersion performance and mechanical properties.

[0034] In some embodiments, the fiber in step S12 can be a natural fiber and / or a synthetic fiber. The synthetic fiber can be, for example, at least one of polyamide fiber (nylon), polypropylene fiber, polyvinyl alcohol fiber, polyester fiber, and polyacrylonitrile fiber. In some embodiments, the fiber in step S12 can be a hyperbranched fiber modified with a branching agent. Hyperbranched fibers are materials obtained by introducing branched structures into the molecular structure of the fiber or a polymer system, and hyperbranched fibers possess rich three-dimensional configurations. Using hyperbranched fibers can further enhance the network complexity of the fiber after subsequent fibrillation, providing a more effective skeletal function. The branching agent can be, for example, a hydrophilic monomer such as pentaerythritol or a tricarboxylic acid, giving the fiber a certain degree of hydrophilicity. The amount of branching agent added can be 0.5~4wt% of the total fiber weight. The fineness of the hyperbranched fiber can be less than 0.5 dtex, and the length can be 1~15 mm.

[0035] In some embodiments, step S12 includes: adding the fiber and dispersant to an alkaline solution (e.g., caustic soda solution) with a mass concentration of 5-30%, and stirring at 100-200 rpm for 1-2 hours at 80-120°C to pre-hydrolyze the fiber under relatively mild conditions, thereby obtaining a fiber dispersion. The alkaline solution can be, for example, a caustic soda solution. The dispersant can be, for example, PVP (polyvinylpyrrolidone) or PAAS (sodium polyacrylate), and the amount of dispersant added can be 0.2-1% of the mass of the alkaline solution. The mass ratio of fiber to alkaline solution is 1:(30-50).

[0036] In some embodiments, step S13, stirring includes: stirring with a high-shear turbine mixer at a speed of 5000~20000 rpm for 10~20 min to induce fibrillation of the fibers. The degree of fiber splitting is controlled at 30-60% by adjusting the shear force and time. Post-treatment includes: multiple water washing followed by hot air drying to fully unfold the nano- or submicron-scale branched structure of the fibrillated fibers. The mass ratio of SiO2 aqueous dispersion to fiber dispersion is 1:(10~20).

[0037] In some embodiments, step S14 includes: immersing the fibrillated fibers in an aqueous polyurethane emulsion with a mass concentration of 1-5%, and then drying them with hot air.

[0038] In some embodiments, step S15 includes: adding the coated fibers and SiO2 aqueous dispersion to the aqueous polyurethane emulsion, stirring at 400-600 rpm for 5-15 min, adding other additives and continuing stirring for 20-40 min, and then performing vacuum degassing at -0.06--0.1 MPa for 10-20 min to obtain a well-dispersed composite polyurethane emulsion. Other additives may include at least one of thickener, defoamer, curing agent, and matte resin. The mass ratio of the coated fibers to the aqueous polyurethane emulsion is 1:(50-100), and the mass ratio of the SiO2 aqueous dispersion to the aqueous polyurethane emulsion is 1:(10-20).

[0039] The present invention also proposes a composite polyurethane emulsion, which is prepared by the method described above.

[0040] refer to Figure 2 The present invention also proposes a method for preparing a wear-resistant surface material with self-cleaning function, comprising the following steps:

[0041] S21, Prepare the substrate layer;

[0042] S22, A pattern layer is formed on the surface of the substrate layer;

[0043] S23, the composite polyurethane emulsion as described above is coated onto the surface of the substrate layer on which the patterned layer is formed to form a wear-resistant layer.

[0044] In some embodiments, in step S21, a substrate layer is prepared using a mixture comprising thermoplastic material and polyurethane graft modifier, wherein the mass of polyurethane graft modifier is 1-10% of the mass of thermoplastic material. By using polyurethane graft modifier to reinforce the interface, the bonding strength between the wear-resistant layer and the substrate layer can be improved, further enhancing wear resistance. The thermoplastic material and polyurethane graft modifier can be uniformly mixed, melt-blended using an extrusion calendering device, extruded into a film, and then cooled and shaped. Specifically, the modifier grafting rate is >5%, film thickness is 0.5-1.2 mm, screw melting temperature is 190-210°C, cooling roller temperature is 40-100°C, decreasing gradually, and linear speed is 5-15 m / min.

[0045] Thermoplastic materials may include thermoplastic resins and / or thermoplastic elastomers. Thermoplastic resins may include at least one of the following: PP (polypropylene), PE (polyethylene), and TPO (thermoplastic polyolefin). Thermoplastic elastomers may include at least one of the following: EVA (ethylene-vinyl acetate copolymer), POE (polyolefin elastomer), EPDM (ethylene propylene diene monomer rubber), and SBS (styrene-butadiene-styrene block copolymer). Polyurethane graft modifiers may, for example, be maleic anhydride.

[0046] Step S22 may include: printing water-based polyurethane base color paste onto the surface of the substrate layer using inkjet printing, gravure printing, transfer printing, or other methods, and then drying it at 80~100℃ to obtain the pattern layer.

[0047] In step S23, the coating thickness can be 10~200μm, and after drying at 100~150℃ for 3~10min, it is left to stand for 60~80h.

[0048] The present invention also proposes a wear-resistant skin material with self-cleaning function, which is prepared by the method described above.

[0049] The following description is based on specific embodiments and comparative examples.

[0050] Example 1

[0051] 1. Preparation of substrate layer

[0052] The thermoplastic material and polyurethane graft modifier are mixed evenly, then melt-blended using an extrusion calendering device. After extrusion into a film, it is cooled and shaped. The modifier addition amount is 5%, and the modifier grafting rate is >5%. Film thickness: 0.8 mm, screw melt temperature: 200℃, cooling roller temperature: 70℃, gradually decreasing, linear speed: 10 m / min.

[0053] 2. Forming a pattern layer

[0054] Water-based polyurethane color paste is printed onto the surface of the substrate layer and dried at 90°C to obtain the pattern layer.

[0055] 3. Formation of a wear-resistant layer

[0056] 3.1 Preparation of SiO2 aqueous dispersion: SiO2 with a particle size of 5~10μm was mixed with water at a mass ratio of 1:5 and stirred at high speed for 30 min at a speed of 2000 rpm. Silane coupling agent (4% of the powder mass) was slowly added dropwise to the high-speed stirred emulsion, and then stirring was continued for 10 min at a speed of 500 rpm to obtain the SiO2 aqueous dispersion.

[0057] 3.2 Fiber pre-hydrolysis: Hyperbranched modified nylon staple fiber was added to a 15% caustic soda solution, and a dispersant was added. The mass ratio of fiber to caustic soda solution was 1:40, and the amount of dispersant added was 0.6% of the mass of caustic soda solution. The mixture was slowly stirred at 150 rpm for 1.5 h at 100 °C to pre-hydrolyze the fiber under relatively mild conditions, resulting in a fiber dispersion.

[0058] 3.3. Fibrillation: A SiO2 aqueous dispersion was added to the fiber dispersion, with a mass ratio of SiO2 aqueous dispersion to fiber dispersion of 1:15. The mixture was stirred at high speed (12000 rpm) for 15 minutes using a high-shear turbine mixer to induce fibrillation. The treated fibers were then washed multiple times with water and dried with hot air to obtain fibrillated fibers.

[0059] 3.4 Coating with polyurethane: The fibrillated fibers are immersed in a 2% aqueous polyurethane solution and then dried with hot air to obtain the coated fibers.

[0060] 3.5 Preparation of composite polyurethane emulsion: The coated fiber and SiO2 aqueous dispersion were added to the aqueous polyurethane emulsion, wherein the mass ratio of the coated fiber to the aqueous polyurethane emulsion was 1:75 and the mass ratio of the SiO2 aqueous dispersion to the aqueous polyurethane emulsion was 1:15. The mixture was stirred at high speed for 10 min at 500 rpm, and then other additives were added. The mixture was stirred for another 30 min, and then vacuum degassed under -0.08 MPa for 15 min to obtain a well dispersed composite polyurethane emulsion.

[0061] 3.6. The prepared composite polyurethane emulsion is uniformly coated on the surface of the substrate to a thickness of 100μm. After drying at 130℃ for 5 minutes, it is allowed to stand for 72 hours to obtain the final product.

[0062] Example 2

[0063] 1. Preparation of substrate layer

[0064] The thermoplastic material and polyurethane graft modifier are mixed evenly, then melt-blended using an extrusion calendering device. After extrusion into a film, it is cooled and shaped. The modifier addition amount is 1%, and the modifier grafting rate is >5%. Film thickness: 0.5 mm, screw melt temperature: 190℃, cooling roller temperature: 40℃, gradually decreasing, linear speed: 5 m / min.

[0065] 2. Forming a pattern layer

[0066] Water-based polyurethane color paste is printed onto the surface of the substrate layer and dried at 80°C to obtain the pattern layer.

[0067] 3. Formation of a wear-resistant layer

[0068] 3.1 Preparation of SiO2 aqueous dispersion: SiO2 with a particle size of 5~10μm was mixed with water at a mass ratio of 1:3 and stirred at high speed for 20 min at a speed of 1500 rpm. Silane coupling agent (3% of the powder mass) was slowly added dropwise to the high-speed stirred emulsion, and then stirring was continued for 5 min at a speed of 400 rpm to obtain the SiO2 aqueous dispersion.

[0069] 3.2 Fiber pre-hydrolysis: Hyperbranched modified nylon staple fiber was added to a 5% caustic soda solution, and a dispersant was added. The mass ratio of fiber to caustic soda solution was 1:30, and the amount of dispersant added was 0.2% of the mass of caustic soda solution. The mixture was stirred slowly at 80℃ for 1 hour at a speed of 100 rpm to pre-hydrolyze the fiber under relatively mild conditions, thus obtaining a fiber dispersion.

[0070] 3.3. Fibrillation: A SiO2 aqueous dispersion is added to the fiber dispersion at a mass ratio of 1:10. The mixture is stirred at high speed (5000 rpm) for 10 minutes using a high-shear turbine mixer to induce fibrillation. The treated fibers are then washed multiple times with water and dried with hot air to obtain fibrillated fibers.

[0071] 3.4 Coating with polyurethane: The fibrillated fibers are immersed in a 1% aqueous polyurethane solution and then dried with hot air to obtain the coated fibers.

[0072] 3.5 Preparation of composite polyurethane emulsion: The coated fiber and SiO2 aqueous dispersion were added to the aqueous polyurethane emulsion, wherein the mass ratio of the coated fiber to the aqueous polyurethane emulsion was 1:50 and the mass ratio of the SiO2 aqueous dispersion to the aqueous polyurethane emulsion was 1:10. The mixture was stirred at high speed for 5 minutes at 400 rpm, and then other additives were added. The mixture was stirred for another 20 minutes, and then vacuum degassed under -0.06 MPa for 10 minutes to obtain a well dispersed composite polyurethane emulsion.

[0073] 3.6. The prepared composite polyurethane emulsion is uniformly coated on the surface of the substrate to a thickness of 10μm. After drying at 100℃ for 3 minutes, it is allowed to stand for 60 hours to obtain the final product.

[0074] Example 3

[0075] 1. Preparation of substrate layer

[0076] The thermoplastic material and polyurethane graft modifier are mixed evenly, then melt-blended using an extrusion calendering device. After extrusion into a film, it is cooled and shaped. The modifier addition is 10%, and the grafting rate of the modifier is >5%. Film thickness: 1.2 mm, screw melt temperature: 210℃, cooling roller temperature: 100℃, gradually decreasing, linear speed: 15 m / min.

[0077] 2. Forming a pattern layer

[0078] Water-based polyurethane color paste is printed onto the surface of the substrate layer and dried at 100°C to obtain the pattern layer.

[0079] 3. Formation of a wear-resistant layer

[0080] 3.1 Preparation of SiO2 aqueous dispersion: SiO2 with a particle size of 5~10μm was mixed with water at a mass ratio of 1:7 and stirred at high speed for 40 min at a speed of 2500 rpm. Silane coupling agent (5% of the powder mass) was slowly added dropwise to the high-speed stirred emulsion, and then stirring was continued for 15 min at a speed of 600 rpm to obtain the SiO2 aqueous dispersion.

[0081] 3.2 Fiber pre-hydrolysis: Hyperbranched modified nylon staple fiber was added to a 30% caustic soda solution, and a dispersant was added. The mass ratio of fiber to caustic soda solution was 1:50, and the amount of dispersant added was 1% of the mass of caustic soda solution. The mixture was slowly stirred at 120℃ for 2 hours at a speed of 200 rpm to pre-hydrolyze the fiber under relatively mild conditions, thus obtaining a fiber dispersion.

[0082] 3.3. Fibrillation: A SiO2 aqueous dispersion was added to the fiber dispersion at a mass ratio of 1:20. The mixture was stirred at high speed (20,000 rpm) using a high-shear turbine mixer for 20 minutes to induce fibrillation. The treated fibers were then washed multiple times with water and dried with hot air to obtain fibrillated fibers.

[0083] 3.4 Coating with polyurethane: The fibrillated fibers are immersed in a 5% aqueous polyurethane solution and then dried with hot air to obtain the coated fibers.

[0084] 3.5 Preparation of composite polyurethane emulsion: The coated fibers and SiO2 aqueous dispersion were added to the aqueous polyurethane emulsion, wherein the mass ratio of the coated fibers to the aqueous polyurethane emulsion was 1:100 and the mass ratio of the SiO2 aqueous dispersion to the aqueous polyurethane emulsion was 1:20. The mixture was stirred at high speed for 15 min at 600 rpm, and then other additives were added. The mixture was stirred for another 40 min, and then vacuum degassed under -0.1 MPa conditions for 20 min to obtain a well-dispersed composite polyurethane emulsion.

[0085] 3.6. The prepared composite polyurethane emulsion is uniformly coated on the surface of the substrate to a thickness of 200μm. After drying at 150℃ for 10min, it is allowed to stand for 80h to obtain the final product.

[0086] Comparative Example 1

[0087] The main difference between Comparative Example 1 and Example 1 is that step 3.1 was not performed, and SiO2 aqueous dispersion was not added in steps 3.3 and 3.5; all other parts are the same. That is, the composite polyurethane emulsion of Comparative Example 1 includes fibrillated fibers but does not include SiO2 particles.

[0088] Comparative Example 2

[0089] The main difference between Comparative Example 2 and Example 1 is that steps 3.2-3.4 were not performed, and the encapsulated fibers were not added in step 3.5; all other parts are the same. That is, the composite polyurethane emulsion of Comparative Example 2 includes SiO2 particles but does not include fibrillated fibers.

[0090] Comparative Example 3

[0091] The main difference between Comparative Example 3 and Example 1 is that SiO2 aqueous dispersion was not added in step 3.3, while the other parts are the same.

[0092] Comparative Example 4

[0093] The main difference between Comparative Example 4 and Example 1 is that SiO2 aqueous dispersion was not added in step 3.5, while the other parts are the same.

[0094] The skin materials prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to abrasion resistance and self-cleaning performance tests. Abrasion resistance was evaluated using a Tiber abrasion tester, and the Tiber abrasion test method was referenced to ISO 5470-1. The test conditions were: H18 grinding wheel, 1000g load, S-36 pad, 500 revolutions. Self-cleaning performance was evaluated using water contact angle and oil contact angle, and the water contact angle was referenced to ASTM D7334, while the oil contact angle was referenced to GB / T 30693. The test results are shown in Table 1.

[0095] Table 1 Performance test results of Examples 1-3 and Comparative Examples 1-4

[0096]

[0097] As shown in Table 1, Comparative Example 1, which only added fibrillated fibers, and Comparative Example 2, which only added SiO2 particles, both exhibited lower wear resistance and self-cleaning properties than Examples 1-3. This demonstrates that the present invention can effectively improve the wear resistance and self-cleaning properties of the coating by synergistically adding fibrillated fibers and SiO2 particles. Comparative Example 3 did not add SiO2 aqueous dispersion in step 3.3, resulting in poor fibrillation and ultimately lower wear resistance and self-cleaning properties than Examples 1-3. Comparative Example 4 did not add SiO2 aqueous dispersion in step 3.5, leading to insufficient synergistic effect between SiO2 particles and fibrillated fibers, and ultimately lower wear resistance and self-cleaning properties than Examples 1-3.

[0098] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for preparing a composite polyurethane emulsion, characterized in that, Includes the following steps: S11, prepare SiO2 aqueous dispersion; S12 causes the fiber to undergo pre-hydrolysis in an alkaline solution to obtain a fiber dispersion. S13, the SiO2 aqueous dispersion and the fiber dispersion are mixed and stirred and post-treated to obtain fibrillated fibers; S14, a polyurethane coating is coated on the surface of the fibrillated fiber to obtain coated fiber; S15, the wrapped fibers, the SiO2 aqueous dispersion and other additives are added to the aqueous polyurethane emulsion and stirred to obtain a composite polyurethane emulsion.

2. The method according to claim 1, characterized in that, Step S11 includes: mixing SiO2 powder with a particle size of 5~10μm with water at a mass ratio of 1:(3~7) and stirring at a speed of 1500~2500rpm, then adding silane coupling agent and stirring at a speed of 400~600rpm.

3. The method according to claim 1, characterized in that, Step S12 includes: adding the fiber and dispersant to an alkaline solution with a mass concentration of 5-30%, stirring at 100-200 rpm for 1-2 hours at 80-120°C to obtain the fiber dispersion, wherein the mass ratio of the fiber to the alkaline solution is 1:(30-50); in step S12, the fiber is a hyperbranched fiber modified by a branching agent.

4. The method according to claim 1, characterized in that, In step S13, the mass ratio of the SiO2 aqueous dispersion to the fiber dispersion is 1:(10~20); The stirring process includes stirring at a speed of 5000~20000 rpm for 10~20 minutes; the post-treatment process includes washing with water multiple times and then drying.

5. The method according to claim 1, characterized in that, Step S14 includes: immersing the fibrillated fibers in an aqueous polyurethane emulsion with a mass concentration of 1-5%, and then drying them.

6. The method according to claim 1, characterized in that, Step S15 includes: adding the wrapped fiber and the SiO2 aqueous dispersion to the aqueous polyurethane emulsion, stirring at a speed of 400-600 rpm for 5-15 min, and then adding other additives and continuing to stir for 20-40 min; in step S15, the mass ratio of the wrapped fiber to the aqueous polyurethane emulsion is 1:(50-100), and the mass ratio of the SiO2 aqueous dispersion to the aqueous polyurethane emulsion is 1:(10-20).

7. A composite polyurethane emulsion, characterized in that, It is prepared by the method described in any one of claims 1-6.

8. A method for preparing a wear-resistant surface material with self-cleaning function, characterized in that, Includes the following steps: S21, Prepare the substrate layer; S22, a pattern layer is formed on the surface of the substrate layer; S23, the composite polyurethane emulsion as described in claim 7 is coated onto the surface of the substrate layer on which the patterned layer is formed to form a wear-resistant layer.

9. The method according to claim 8, characterized in that, In step S21, the substrate layer is prepared using a mixture comprising thermoplastic material and polyurethane graft modifier, wherein the mass of the polyurethane graft modifier is 1 to 10% of the mass of the thermoplastic material.

10. A wear-resistant surface material with self-cleaning function, characterized in that, It is prepared by the method described in claim 8 or 9.

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