Reinforced polyurethane composite material and preparation method thereof

Abstract

The invention belongs to the technical field of reinforced polymer composite materials, and particularly relates to a reinforced polyurethane composite material and a preparation method thereof. Aiming at the problems of non-uniform reinforcement phase dispersion, weak interface bonding and insufficient medium corrosion resistance of the traditional reinforced polyurethane composite material, the invention provides the composite material with high strength and high corrosion resistance. The material is composed of a component A and a component B, wherein the component A comprises water-based hydroxy acrylic resin, silane modified chopped glass fibers, organic montmorillonite, a silane coupling agent and a plurality of auxiliaries; and the component B is an aliphatic isocyanate curing agent. The silane modified fiber is used as a main reinforcing phase, the modified montmorillonite has auxiliary dispersion and barrier effects, and the silane coupling agent promotes interface bonding, so that the mechanical property and the corrosion resistance of the material are remarkably improved through the synergism of the three components. The composite material is high in bending strength, excellent in strength retention rate after being soaked in saline water for a long time, intact in surface state and suitable for protection of severe environments such as offshore wind power and cross-sea bridges.

Description

Technical Field

[0001] This invention belongs to the field of reinforced polymer composite materials technology, specifically relating to a reinforced polyurethane composite material and its preparation method. Background Technology

[0002] Polyurethane materials, due to their flexible molecular structure, excellent mechanical properties, outstanding wear resistance, good elasticity, and chemical corrosion resistance, have become indispensable polymer materials in modern industry. They come in diverse forms and are widely used in high-performance coatings, adhesives, sealants, flexible and rigid foams, elastomers, and composite materials. They play a crucial role in construction, automotive, rail transportation, wind turbine blades, marine engineering, and outdoor infrastructure, providing important functions such as protection, decoration, sealing, and structural support for substrates.

[0003] With the upgrading of related industries and the continuous expansion of application scenarios, polyurethane materials are facing increasingly stringent performance requirements. Especially in major engineering projects and equipment requiring ultra-long design life, extremely high operational reliability, and long-term exposure to harsh environments such as intense ultraviolet radiation, high-salt and high-humidity marine atmospheres, and wide-frequency temperature fluctuations—for example, in applications such as offshore wind turbine blade and tower protection, steel structure coatings for cross-sea bridges, high-speed train bodies, and coastal chemical facilities—traditional polyurethane materials, while maintaining good toughness and aging resistance, often struggle to simultaneously achieve adequate rigidity, load-bearing strength, and long-term environmental tolerance. Therefore, significantly improving the comprehensive performance of materials under extreme conditions has become a core issue that must be addressed to expand their high-end applications and meet the development needs of key fields.

[0004] To improve the mechanical properties of polyurethane, a conventional method is to introduce fibrous reinforcing fillers, such as glass fiber and carbon fiber, into the matrix. This type of research and practice has been ongoing for many years, aiming to achieve superior strength and modulus through the composite effect of fillers. However, in practical applications, these reinforced polyurethane composites still face several long-standing technical bottlenecks. First, it is difficult to ensure the uniform dispersion of reinforcing fillers in the matrix, especially for fibers with dimensions of micrometers and above, which are prone to agglomeration due to surface energy differences, forming stress concentration points and thus impairing the overall performance and reliability of the material. Second, most fillers have poor interfacial compatibility with the organic polymer matrix, resulting in weak bonding and low stress transfer efficiency, limiting the full realization of their reinforcing effect. Furthermore, traditional polyurethane systems lack sufficient protection when exposed to corrosive media such as water and salt spray for extended periods. These media can easily penetrate into the material, potentially corroding not only the matrix resin but also causing swelling, hydrolysis, and other damage at the filler-matrix interface, leading to significant degradation of mechanical properties and appearance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a reinforced polyurethane composite material and its preparation method. The purpose of this invention is to develop a novel polyurethane composite material that possesses excellent mechanical properties, outstanding resistance to media corrosion, uniform dispersion of the reinforcing phase, and strong interfacial bonding.

[0006] The first aspect of the present invention provides a reinforced polyurethane composite material, comprising component A and component B; Component A comprises the following components by weight: 0.9-1.1 parts of water-based fluorinated high-hydroxyl acrylic acid dispersion resin; 0.85-0.95 parts of GMA-grafted modified waterborne acrylic dispersion resin; 0.03-0.05 parts of ultraviolet absorber; Light stabilizer 0.03-0.05 parts; Pigment 0.35-0.45 parts; 0.25-0.35 parts of wet-processed sericite powder; Nano zinc oxide 0.07-0.08 parts; 0.12-0.18 parts of silane-modified chopped glass fiber; 0.015-0.025 parts of silane coupling agent; 0.025-0.035 parts of organic montmorillonite; Dispersant 0.02-0.03 parts; 0.01-0.02 parts of defoamer; Leveling agent 0.01-0.02 parts; Thickener 0.01-0.02 parts; 0.4-0.5 parts deionized water; Component B includes an aliphatic isocyanate curing agent and a film-forming aid.

[0007] As an optimized option for any of the above-mentioned reinforced polyurethane composite materials, in component B, the film-forming aid is 0.23-0.27 parts by weight, with the aliphatic isocyanate curing agent being 1 part.

[0008] As an optimized embodiment of any of the above-mentioned reinforced polyurethane composite materials, the reinforced polyurethane composite material is composed of component A and component B mixed in a weight ratio of 1:(0.2-0.4); the preferred weight ratio of component A to component B is 1:0.3.

[0009] As an optimized solution for any of the above-mentioned reinforced polyurethane composite materials, the length of the silane-modified chopped glass fiber is 3-5 mm. The silane modification is achieved by surface grafting modification of the chopped glass fiber using KH-560 silane coupling agent.

[0010] As an optimized option for any of the above-mentioned reinforced polyurethane composite materials, the organomontmorillonite is montmorillonite modified with hexadecyltrimethylammonium bromide.

[0011] As an optimized scheme for any of the above-mentioned reinforced polyurethane composite materials, the weight ratio of silane-modified chopped glass fiber to organomontmorillonite in component A is (4-6):1.

[0012] As an optimized option for any of the above-mentioned reinforced polyurethane composite materials, the film-forming aid is propylene glycol diacetate; the pigment is rutile titanium dioxide; the ultraviolet absorber is a benzotriazole ultraviolet absorber; the light stabilizer is a light-hindered amine stabilizer; and the silane coupling agent is KH-550.

[0013] A second aspect of the present invention is to provide a method for preparing the above-mentioned reinforced polyurethane composite material, comprising the following steps: Preparation of component A: S1: Under stirring conditions, mix deionized water, dispersant and defoamer evenly; S2: While stirring, add the ultraviolet absorber, light stabilizer, pigment, wet sericite powder, nano zinc oxide, and organomontmorillonite in sequence. After mixing evenly, add the silane coupling agent, then add the silane-modified chopped glass fiber, and continue stirring to obtain the mixed slurry. S3: Grind the mixed slurry to a fineness of ≤50μm, and then degas it; S4: Add water-based fluorinated high-hydroxyl acrylic dispersion resin, GMA grafted modified water-based acrylic dispersion resin, leveling agent and thickener to the slurry after step S3, stir and adjust to uniform viscosity, filter, and obtain component A. Preparation of component B: The aliphatic isocyanate curing agent and the film-forming aid are mixed and stirred evenly to obtain component B; Preparation of composite materials: Add component B to component A and stir until homogeneous to obtain the reinforced polyurethane composite material.

[0014] As a further optimization of the preparation method of the above-mentioned reinforced polyurethane composite material, silane-modified chopped glass fibers are prepared by the following steps: alkali-free chopped glass fibers with a length of 3-5 mm are ultrasonically cleaned in a mixed solution of ethanol and deionized water, and then dried; KH-560 silane coupling agent is added to the mixed solvent of ethanol and deionized water, the pH is adjusted to 4-5, and the mixture is stirred to hydrolyze the fibers, obtaining a hydrolysate; the dried chopped glass fibers are added to the hydrolysate, and a grafting reaction is carried out by constant temperature stirring at 50-60℃; after the reaction is completed, the fibers are filtered to separate them, washed, and dried to obtain silane-modified chopped glass fibers.

[0015] As a further optimization of the preparation method of the above-mentioned reinforced polyurethane composite material, organomontmorillonite is prepared by the following steps: natural sodium-based montmorillonite is dried, pulverized and sieved; hexadecyltrimethylammonium bromide is dissolved in deionized water to prepare an aqueous solution; montmorillonite powder is added to the hexadecyltrimethylammonium bromide aqueous solution and stirred at a constant temperature of 60-70℃ to carry out an ion exchange reaction; after the reaction is completed, the solid is collected by centrifugation, washed until no free bromide ions are present, and then dried, ground and sieved to obtain organomontmorillonite.

[0016] Beneficial effects The reinforced polyurethane composite material provided by this invention exhibits significantly superior comprehensive performance compared to traditional polyurethane systems. This material not only demonstrates excellent mechanical strength and structural load-bearing capacity, but also maintains high performance stability in long-term corrosive environments, exhibiting no blistering, whitening, or rusting on the surface, demonstrating outstanding corrosion resistance and durability. Simultaneously, the material system possesses good construction adaptability and storage stability, with uniform dispersion of components, minimal agglomeration, and ease of coating or molding. Overall, this invention successfully overcomes the problems of difficult reinforcement phase dispersion, weak interfacial bonding, and insufficient environmental erosion resistance in common composite materials, obtaining a multifunctional composite material that combines high strength, high corrosion resistance, and good processability, thus broadening the application range of polyurethane materials in harsh environments. Detailed Implementation

[0017] The present invention is further illustrated below with specific embodiments. These embodiments are exemplary and intended to illustrate the problem and explain the present invention, and are not intended to be limiting.

[0018] Example 1 The reinforced polyurethane composite material of this embodiment includes component A and component B, with a weight ratio of component A to component B of 1:0.3.

[0019] Component A includes: Waterborne fluorinated high hydroxyl value hydroxyl acrylic acid dispersion resin (Shiquanxing 2233F): 1.0 parts by weight; GMA grafted modified waterborne acrylic dispersion resin (Shiquanxing 5136): 0.9 parts by weight; Benzotriazole UV absorber (Tinuvin 1130): 0.04 parts by weight; Light-hindered amine stabilizer (Tinuvin 292): 0.04 parts by weight; Rutile titanium dioxide CR828: 0.4 parts by weight; Wet-processed sericite powder (Chuzhou Gerui): 0.3 parts by weight; Nano zinc oxide (particle size 20-50nm): 0.075 parts by weight; Silane-modified chopped glass fibers (3-5 mm in length, KH-560 surface modified): 0.15 parts by weight; Silane coupling agent KH-550: 0.02 parts by weight; Organomontmorillonite (modified with hexadecyltrimethylammonium bromide): 0.03 parts by weight; Dispersant (BYK-183): 0.025 parts by weight; Defoamer (BYK-093): 0.015 parts by weight; Leveling agent (TEGO-450): 0.015 parts by weight; Thickener (BYK-420): 0.015 parts by weight; Deionized water: 0.45 parts by weight.

[0020] Component B includes: Aliphatic isocyanate curing agent (Bayhydurxp2655): 1.0 part by weight; Propylene glycol diacetate (PGDA): 0.25 parts by weight.

[0021] The preparation method of component A includes the following steps: Step S1: Add deionized water to a stainless steel mixing tank, turn on high-speed stirring (1200r / min), add BYK-183 dispersant and BYK-093 defoamer in sequence, and continue stirring for 5 minutes until completely dissolved.

[0022] Step S2: Keep the rotation speed at 1200 r / min, and add Tinuvin 1130, Tinuvin 292, CR828 titanium dioxide, wet sericite powder, nano zinc oxide, and organomontmorillonite in sequence (each at 1 min intervals). After adding the materials, stir at high speed for 10 min. Then add silane coupling agent KH-550 and continue stirring at high speed for 5 min. Then slowly add silane-modified chopped glass fiber and stir at high speed at 1200 r / min for 15 min to form a uniform slurry.

[0023] Step S3: Transfer the slurry to a sand mill and grind it to a fineness of ≤50μm (to avoid excessive breakage of glass fibers). After returning it to the mixing tank, switch to low-speed stirring (500r / min) for 10min to eliminate air bubbles.

[0024] Step S4: While stirring at 500 rpm, add Shiquanxing 2233F resin and Shiquanxing 5136 resin in sequence. After stirring for 5 minutes, add TEGO-450 leveling agent and BYK-420 thickener. Adjust the speed to 800 rpm and stir for 9 minutes until the system is homogeneous (Ford-4 cup viscosity 29s, 25℃). Finally, filter through an 80-mesh filter to obtain component A.

[0025] The preparation method of component B includes the following steps: add Bayhydurxp2655 curing agent to a clean plastic mixing tank, start medium-speed stirring (800r / min), slowly add PGDA film-forming aid (addition time 2min), and continue stirring for 9min until uniform and without stratification to obtain component B.

[0026] The preparation of reinforced polyurethane composite material includes the following steps: add component B slowly to component A at a weight ratio of A:B=1:0.3, turn on low speed stirring (600r / min) for 6min to mix evenly (avoid glass fiber agglomeration), and obtain reinforced polyurethane composite material that meets the conditions for coating or molding construction.

[0027] Examples 2-5 The composition and dosage of components A and B in Examples 2-5 are shown in Table 1. The preparation methods of components A, B, and the reinforced polyurethane composite materials are the same as those in Example 1.

[0028] Table 1. Composition and dosage of component A in each embodiment. Note: In all embodiments, the weight ratio of components A and B is maintained at 1:0.3.

[0029] In the above embodiments, the specific modification and preparation process of silane-modified chopped glass fibers (3-5 mm in length, KH-560 surface modified) is as follows: Using alkali-free chopped glass fibers with a length of 3-5 mm as the substrate, the fibers were first ultrasonically cleaned for 25 minutes in a mixed solution of ethanol and deionized water at 55°C (9:1 volume ratio) to remove surface release agent and dust. Then, they were transferred to a 90°C forced-air drying oven and dried for 2.5 hours until completely dehydrated. Next, a mixed solvent of ethanol and deionized water at a 9:1 volume ratio was added to a three-necked flask, and KH-560 silane coupling agent was added at 2% of the total solvent mass. After stirring evenly, glacial acetic acid was added dropwise to adjust the pH of the system to 4.5, and the mixture was stirred at 35°C for 20 minutes. KH-560 was fully hydrolyzed into an active intermediate containing silanol groups. The pretreated chopped glass fibers were then added to the hydrolysate at a solid-liquid ratio of 1:12. The mixture was stirred at 55°C for 1.5 hours to allow the silanol groups in the hydrolysate to undergo a dehydration condensation reaction with the hydroxyl groups on the glass fiber surface, thereby grafting KH-560 onto the fiber surface and exposing epoxy groups. Finally, the fibers were filtered to separate them, rinsed three times with anhydrous ethanol to remove free KH-560, and dried at 115°C for 1.2 hours to complete the crosslinking and curing process, resulting in silane-modified chopped glass fibers.

[0030] In the above embodiments, the specific modification and preparation process of organomontmorillonite (modified with hexadecyltrimethylammonium bromide) is as follows. Using natural sodium-based montmorillonite as raw material, it was first dried in a 108℃ oven for 5 hours to remove water, then pulverized and passed through a 200-mesh sieve to obtain a uniform powder. Subsequently, hexadecyltrimethylammonium bromide (CTAB) was added to deionized water, heated to 65℃ and stirred until completely dissolved to prepare a 3% (w / w) CTAB aqueous solution. Then, according to the mass ratio of montmorillonite to CTAB of 1:0.3 and the solid-liquid ratio of 1:12, the montmorillonite powder was slowly added to the CTAB aqueous solution, and stirred at 65℃ for 3 hours to allow the sodium ions between the montmorillonite layers to undergo ion exchange with the hexadecyltrimethyl cations dissociated from CTAB, allowing the long-chain alkyl groups to embed into the interlayer and expand the interlayer spacing. Finally, the system was centrifuged at 3500 r / min for 12 min, and the lower solid was collected and repeatedly washed with deionized water until no white precipitate (no free Br⁻) was added to the washing liquid. The solid was then dried in an 85℃ oven for 7 hours, ground, and passed through a 200-mesh sieve to obtain organo-montmorillonite.

[0031] Comparative Example 1 Based on the scheme of Example 1, the only difference from Example 1 is that silane-modified chopped glass fibers (3-5 mm in length, KH-560 surface modified) are not added to component A. The types, amounts and preparation methods of the other components are completely consistent with those of Example 1.

[0032] Comparative Example 2 Based on the scheme of Example 1, the only difference from Example 1 is that organomontmorillonite (modified with hexadecyltrimethylammonium bromide) is not added to component A, while the types, amounts and preparation methods of the other components are completely consistent with those of Example 1.

[0033] Comparative Example 3 Based on the scheme of Example 1, the only difference from Example 1 is that silane-modified chopped glass fibers (3-5 mm in length, KH-560 surface modified) and organomontmorillonite (modified by hexadecyltrimethylammonium bromide) are not added to component A. The types, amounts and preparation methods of the other components are completely consistent with those of Example 1.

[0034] Comparative Example 4 Based on the scheme of Example 1, the only difference from Example 1 is that the "organo-montmorillonite (modified with hexadecyltrimethylammonium bromide)" in component A is replaced with an equal part by weight of "ordinary montmorillonite (not modified with hexadecyltrimethylammonium bromide)", and the amount is still 0.03 parts by weight. The types, amounts and preparation methods of the other components are completely consistent with those of Example 1.

[0035] Test case Bending strength tests were conducted according to GB / T9341-2008 "Determination of Bending Properties of Plastics". Standard specimens of 80mm×10mm×4mm were prepared from the reinforced polyurethane composites of each example (1-5) and comparative example (1-4), with 5 parallel specimens prepared for each group. A universal testing machine was used, with a span of 40mm and a loading speed of 2mm / min. Three-point bending loads were applied to the specimens until fracture, and the maximum load value was recorded. The bending strength was calculated using the formula (σ=3FL / (2bh²), where F is the maximum load, L is the span, b is the specimen width, and h is the specimen thickness). The average value of the 5 parallel specimens was taken as the final bending strength data, and the data were compiled and recorded in Table 2.

[0036] According to GB / T1763-1979 "Determination of Chemical Resistance of Coating Film", the test conditions were adjusted. The composite material samples (50mm×50mm×4mm) of each example and comparative example were immersed in 3.5% sodium chloride aqueous solution, and the temperature was maintained at 25℃. After immersion for 168h, the samples were taken out, rinsed with deionized water and dried. The flexural strength of the samples after immersion was measured, and the flexural strength retention rate (flexural strength after immersion / flexural strength before immersion × 100%) was calculated. At the same time, it was observed whether there were blistering, whitening, rust and other phenomena on the sample surface. The results were recorded in Table 2.

[0037] Table 2 Test Results As can be clearly seen from the test results in Table 2, the reinforced polyurethane composite materials prepared in Examples 1-5 all exhibit excellent comprehensive performance. Regarding flexural strength, the flexural strength of the samples in each example ranges from 28.6 MPa to 32.5 MPa, with Examples 1 and 4 showing particularly outstanding flexural strengths, reaching 32.5 MPa and 32.3 MPa respectively, demonstrating good mechanical load-bearing capacity. In terms of resistance to media, after immersion in a 3.5% sodium chloride aqueous solution for 168 hours, the flexural strength retention rate of all examples remained above 93.5%, with Example 1 achieving a retention rate as high as 99.2%. Furthermore, no blistering, whitening, or corrosion was observed on the surface of any of the sample samples, indicating that the materials possess excellent resistance to salt water corrosion and can meet the requirements of use in harsh environments. This fully demonstrates that the formulation system and preparation process adopted in this invention have excellent stability and reliability.

[0038] Comparative Example 1, lacking silane-modified chopped glass fibers, exhibited a flexural strength of only 19.3 MPa, a significant decrease from 32.5 MPa in Example 1. The 168-hour salt water resistance flexural strength retention rate also dropped to 87.9%, indicating that silane-modified chopped glass fibers play a crucial role in improving the material's mechanical strength and resistance to corrosive media. Through synergistic interaction with the matrix, they enhance the material's structural integrity. Comparative Example 2, without the addition of organomontmorillonite, showed a flexural strength reduced to 25.7 MPa, with a salt water resistance flexural strength retention rate of only 72.6%, and localized slight whitening of the surface. This suggests that the hexadecyltrimethylammonium bromide-modified organomontmorillonite not only helps improve the material's mechanical properties but also enhances its resistance to media penetration through its layered barrier effect, reducing the erosion of the matrix by corrosive media. Comparative Example 3, lacking both silane-modified chopped glass fiber and modified organo-montmorillonite, exhibited a flexural strength of only 16.8 MPa and a salt water resistance flexural strength retention rate as low as 71.2%, making it the worst performing sample among all tested samples. This further confirms the synergistic effect of the two components in improving material performance. Comparative Example 4, using ordinary montmorillonite instead of modified organo-montmorillonite, achieved a flexural strength of 24.1 MPa and a salt water resistance flexural strength retention rate of 78.3%. While better than Comparative Examples 2 and 3, it was significantly lower than Example 1. This indicates that the cetyltrimethylammonium bromide modification of montmorillonite significantly improves its compatibility, dispersibility, and barrier effect within the system, while ordinary montmorillonite falls far short of achieving the same modification effect.

[0039] Based on the test results and analysis of the above embodiments and comparative examples, it can be seen that the reinforced polyurethane composite material formulation system provided by the present invention can effectively solve the key problems of poor fiber dispersion, weak bonding with the matrix, and insufficient resistance to media in traditional polyurethane composite materials. Silane-modified chopped glass fibers, as a reinforcing phase, enhance the mechanical strength of the material. Specific modified organomontmorillonite, through its layered structure, can coat the fiber surface and be uniformly dispersed in the system, preventing fiber aggregation. Simultaneously, its lamellar barrier effect can also help improve the material's resistance to media penetration. Silane-modified chopped glass fibers, as a reinforcing phase, enhance the mechanical strength of the material; modified organomontmorillonite, through its layered structure, achieves dispersion assistance and media barrier properties; and the silane coupling agent promotes interfacial bonding between the components. The synergistic effect of these three components gives the material both excellent mechanical properties and corrosion resistance.

[0040] The above embodiments are exemplary and are intended to illustrate the technical concept and features of the present invention, so that those skilled in the art can understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A reinforced polyurethane composite material, characterized in that, Includes component A and component B; Component A comprises the following components by weight: 0.9-1.1 parts of water-based fluorinated high-hydroxyl acrylic acid dispersion resin; 0.85-0.95 parts of GMA-grafted modified waterborne acrylic dispersion resin; 0.03-0.05 parts of ultraviolet absorber; Light stabilizer 0.03-0.05 parts; Pigment 0.35-0.45 parts; 0.25-0.35 parts of wet-processed sericite powder; Nano zinc oxide 0.07-0.08 parts; 0.12-0.18 parts of silane-modified chopped glass fiber; 0.015-0.025 parts of silane coupling agent; 0.025-0.035 parts of organic montmorillonite; Dispersant 0.02-0.03 parts; 0.01-0.02 parts of defoamer; Leveling agent 0.01-0.02 parts; Thickener 0.01-0.02 parts; 0.4-0.5 parts deionized water; Component B includes an aliphatic isocyanate curing agent and a film-forming aid.

2. The reinforced polyurethane composite material according to claim 1, characterized in that, In component B, the film-forming aid is 0.23-0.27 parts by weight, with the aliphatic isocyanate curing agent being 1 part by weight.

3. The reinforced polyurethane composite material according to claim 2, characterized in that, The reinforced polyurethane composite material is made by mixing component A and component B in a weight ratio of 1:(0.2-0.4).

4. The reinforced polyurethane composite material according to any one of claims 1-3, characterized in that, The length of the silane-modified chopped glass fiber is 3-5 mm, and the silane modification is performed by surface grafting modification of the chopped glass fiber using KH-560 silane coupling agent.

5. The reinforced polyurethane composite material according to claim 4, characterized in that, The organomontmorillonite is montmorillonite modified with hexadecyltrimethylammonium bromide.

6. The reinforced polyurethane composite material according to claim 1, characterized in that, In component A, the weight ratio of the silane-modified chopped glass fiber to the organomontmorillonite is (4-6):

1.

7. The reinforced polyurethane composite material according to claim 1, characterized in that, The film-forming aid is propylene glycol diacetate; the pigment is rutile titanium dioxide; the ultraviolet absorber is a benzotriazole ultraviolet absorber; the light stabilizer is a light-hindered amine stabilizer; and the silane coupling agent is KH-550.

8. A method for preparing a reinforced polyurethane composite material according to any one of claims 1-7, characterized in that, Includes the following steps: Preparation of component A: S1: Under stirring conditions, mix deionized water, dispersant and defoamer evenly; S2: While stirring, add the ultraviolet absorber, light stabilizer, pigment, wet sericite powder, nano zinc oxide, and organomontmorillonite in sequence. After mixing evenly, add the silane coupling agent, then add the silane-modified chopped glass fiber, and continue stirring to obtain the mixed slurry. S3: Grind the mixed slurry to a fineness of ≤50μm, and then degas it; S4: Add water-based fluorinated high-hydroxyl acrylic dispersion resin, GMA grafted modified water-based acrylic dispersion resin, leveling agent and thickener to the slurry after step S3, stir and adjust to uniform viscosity, filter, and obtain component A. Preparation of component B: The aliphatic isocyanate curing agent and the film-forming aid are mixed and stirred evenly to obtain component B; Preparation of composite materials: Add component B to component A and stir until homogeneous to obtain the reinforced polyurethane composite material.

9. A method for preparing a reinforced polyurethane composite material according to claim 8, characterized in that, The silane-modified chopped glass fibers are prepared using the following steps: alkali-free chopped glass fibers with a length of 3-5 mm are ultrasonically cleaned in a mixed solution of ethanol and deionized water, and then dried; KH-560 silane coupling agent is added to the mixed solvent of ethanol and deionized water, the pH is adjusted to 4-5, and the mixture is stirred to hydrolyze the fibers, yielding a hydrolysate; the dried chopped glass fibers are added to the hydrolysate, and a grafting reaction is carried out at a constant temperature of 50-60°C with stirring; after the reaction is complete, the fibers are filtered to separate them, washed, and dried to obtain the silane-modified chopped glass fibers.

10. A method for preparing a reinforced polyurethane composite material according to claim 8, characterized in that, The organic montmorillonite is prepared by the following steps: drying, pulverizing and sieving natural sodium montmorillonite; dissolving hexadecyltrimethylammonium bromide in deionized water to prepare an aqueous solution; adding the montmorillonite powder to the hexadecyltrimethylammonium bromide aqueous solution and stirring at a constant temperature of 60-70°C to carry out an ion exchange reaction. After the reaction was complete, the solid was collected by centrifugation, washed until no free bromide ions were found, and then dried, ground and sieved to obtain the organomontmorillonite.

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