Wear-resistant sealing rubber strip and preparation method thereof

Abstract

The invention belongs to the technical field of rubber products, and discloses a wear-resistant sealing rubber strip and a preparation method thereof.The rubber strip is composed of an elastomer matrix, graft-modified nano-silica, surface-activated aramid staple fibers and solid lubricating filler, the nano-silica is grafted with a bifunctional silane coupling agent containing an epoxy group and an amino group, and the surface-activated aramid staple fibers are grafted with the solid lubricating filler; the solid lubricating filler and aramid staple fibers which are subjected to plasma treatment and coated with isocyanate prime coat form a compact skeleton network with covalent bonds and strong hydrogen bond interaction, the solid lubricating filler is distributed in skeleton gaps in a limited mode, a low-friction film layer is formed in situ in the friction process, and fiber pulling-out is restrained. The structure has an interface cooperation effect and a function coupling effect, compression set and low-temperature flexibility can be improved while abrasion resistance is remarkably improved, DIN abrasion and compression set are both reduced, the low-temperature springback retention degree is improved, comprehensive performance optimization of abrasion resistance, springback and flexibility is achieved, and the structure is suitable for high-durability occasions of automobile doors, windows and mechanical seals.

Description

Technical Field

[0001] This invention belongs to the field of rubber product technology, specifically relating to a wear-resistant sealing strip and its preparation method. Background Technology

[0002] Sealing strips are widely used in the automotive, rail transportation, machinery, and building door and window industries to achieve functions such as sealing, dustproofing, sound insulation, and vibration damping. Common sealing strips are mostly based on ethylene propylene diene monomer (EPDM), thermoplastic vulcanizate (TPV), silicone rubber, or chloroprene rubber (CR) elastomers, with the addition of inorganic fillers, reinforcing fibers, or lubricants to improve their mechanical properties and processability. In actual use, sealing strips are subjected to repeated compression, friction, and environmental aging, especially with frequent contact and friction between their outer surface and door / window frames, mechanical tracks, etc., making them prone to wear, surface cracking, and hardening, leading to sealing failure.

[0003] To improve wear resistance, existing technologies often employ single-method modifications, such as adding nano-silica to increase hardness and wear resistance, introducing aramid fibers to enhance tear resistance, or adding solid lubricants to reduce the coefficient of friction. However, these single-method modifications have limitations: high-filling hard particles reduce the resilience and low-temperature flexibility of the sealing strip; reinforcing fibers are easily pulled out during long-term friction, causing interfacial peeling; uneven dispersion or migration of lubricants makes it difficult to maintain the wear resistance effect in the long term. Furthermore, while simple combinations of multiple components can address some properties, they lack interfacial synergy, and the overall performance improvement often exhibits a linear additive effect or even mutual attenuation. Therefore, there is an urgent need for a sealing strip technology that can improve wear resistance while maintaining or even improving compression set performance and low-temperature flexibility. Summary of the Invention

[0004] To address the shortcomings mentioned in the background art, the present invention aims to provide a wear-resistant sealing strip and its preparation method. The strip is based on an elastomer matrix, supplemented with grafted modified nano-silica, surface-activated aramid short fibers, and solid lubricating fillers. A dense skeleton network is constructed through interfacial chemical bonds and strong hydrogen bonds, and the lubricating phase is restrictedly distributed. During the friction process, a low-friction film layer is formed in situ, effectively inhibiting fiber pull-out.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A wear-resistant sealing strip comprises the following raw materials in parts by weight: 100 parts of elastomer matrix, 5-25 parts of modified nano-silica, 1-8 parts of surface-activated aramid short fiber, 1-10 parts of solid lubricating filler, 0.5-3 parts of vulcanizing agent, 0.5-2 parts of accelerator, 1-3 parts of antioxidant, and 0.5-2 parts of processing aid;

[0007] The modified nano-silica surface is grafted with a bifunctional silane coupling agent containing epoxy and amino groups.

[0008] The surface-activated aramid short fibers are plasma-treated and coated with an isocyanate base coating. The solid lubricating filler is selected from one or more of polytetrafluoroethylene micro powder, graphite, hexagonal boron nitride, or molybdenum disulfide.

[0009] More preferably, the method for preparing modified nano-silica includes the following steps:

[0010] S101: Nano-silica is dispersed in anhydrous alcohol solvent and mixed with silane coupling agents containing epoxy and amino groups to prepare a coupling pretreatment solution;

[0011] S102: The coupling pretreatment liquid is added to the nano-silica dispersion system, and a grafting condensation reaction is carried out under stirring and heating conditions to obtain a modified slurry;

[0012] S103: The modified slurry is subjected to solid-liquid separation, and is washed, dried and depolymerized and sieved in sequence to obtain grafted modified nano-silica.

[0013] More preferably, the method for preparing surface-activated aramid staple fibers includes the following steps:

[0014] S201: Spread aramid staple fibers evenly on the worktable of the plasma treatment device, set appropriate atmosphere and power conditions, and turn on the plasma source to perform all-round activation treatment on the fiber surface.

[0015] S202: Take out the plasma-activated aramid short fibers and immediately place them in the spraying station. Spray the prepared isocyanate solution evenly onto the fiber surface through the nozzle.

[0016] S203: Place the sprayed aramid staple fiber in a clean and dry environment, let it stand and cure at room temperature until the base coating is completely formed, and keep the fiber in a dispersed state to finally obtain surface-activated aramid staple fiber with a base coating.

[0017] More preferably, the elastomer matrix is ​​one or more of EPDM rubber, thermoplastic vulcanized rubber, silicone rubber, chloroprene rubber, or nitrile rubber.

[0018] More preferably, the particle size of the solid lubricating filler is 0.5 to 10 μm.

[0019] More preferably, the vulcanizing agent is di-tert-butyl peroxide, sulfur, or a combination thereof, and the accelerator is N-cyclohexyl-2-benzothiazole sulfenamide, dithiocarbamate, or a combination thereof.

[0020] More preferably, the antioxidant is selected from antioxidant 4010NA, antioxidant RD, or a combination thereof, and the processing aid is selected from paraffin wax, stearic acid, polyethylene glycol, or a combination thereof.

[0021] A method for preparing a wear-resistant sealing strip includes the following steps:

[0022] S1. Weigh the elastomer matrix and the grafted modified nano silica together and put them into a mixer. Stir and mix at a temperature of 90-110 ℃ for 4-6 minutes to make the nano silica uniformly dispersed and form a preliminary skeleton phase with the matrix.

[0023] S2. Add surface-activated aramid short fibers and solid lubricating fillers to the skeleton phase, control the rotor speed to 30-40 rpm and the temperature to 80-100 ℃, and perform low-shear mixing for 3-5 minutes; add vulcanizing agent, accelerator, antioxidant and processing aid to the mixture in sequence, and continue mixing at 70-90 ℃ for 2-4 minutes.

[0024] S3. The mixed rubber compound is co-extruded in two layers using a twin-screw extruder or parallel twin-unit extrusion molding process. The total content of grafted modified nano-silica, surface-activated aramid short fibers and solid lubricating fillers in the outer layer is controlled to be more than 1.5 times higher than that in the inner layer. After extrusion, it is vulcanized in hot air or salt bath on a continuous vulcanization production line at a vulcanization temperature of 160-190 ℃ for 5-12 minutes. Finally, it is cooled, cut and shaped to obtain the finished wear-resistant sealing strip.

[0025] More preferably, the outer layer of the double-layer co-extrusion molding has a Shore A hardness of 70-85, the inner layer has a Shore A hardness of 45-60, and the total content of grafted modified nano-silica, surface-activated aramid short fibers and solid lubricant fillers in the outer layer is higher than that in the inner layer.

[0026] The beneficial effects of this invention are:

[0027] This invention optimizes the material system and designs the interface structure by introducing grafted and modified nano-silica, surface-activated aramid short fibers, and solid lubricant fillers into wear-resistant sealing strips. A step-by-step mixing and double-layer co-extrusion molding process is employed to achieve a comprehensive improvement in wear resistance, resilience, and low-temperature flexibility. The nano-silica, grafted with a bifunctional silane coupling agent containing epoxy and amino groups, forms a dense skeletal network with the aramid short fibers activated by plasma and isocyanate primer, exhibiting both chemical and strong hydrogen bonds. This significantly enhances the interfacial bonding strength between the reinforcing phase and the matrix, inhibiting fiber pull-out and interfacial peeling during friction. The solid lubricant filler, confined within the skeletal gaps, forms a continuous low-friction film layer in situ at the contact surface during friction, reducing the coefficient of friction and minimizing wear heat accumulation, thus extending the duration of wear resistance.

[0028] The gradient hardness dual-layer structure design ensures that the outer layer has higher hardness to resist wear, while the inner layer maintains lower hardness to provide excellent compression resilience and sealing adaptability, balancing durability and sealing performance. The stepwise mixing process guarantees the spatially confined distribution and orientation of the reinforcing and lubricating phases, avoiding high shear damage to fiber morphology and improving filler dispersion uniformity. This not only significantly reduces DIN wear but also, under high wear-resistant conditions, reduces compression set by more than 25% and improves low-temperature resilience retention, exhibiting a nonlinear synergistic effect exceeding the effects of any single modifier. Attached Figure Description

[0029] The invention will now be further described with reference to the accompanying drawings.

[0030] Figure 1 This is a comparison of FTIR images of grafted modified silica and unmodified silica according to the present invention.

[0031] Figure 2 The bar charts show the DIN wear of Examples 1-3 and Comparative Examples 1-2. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] I. Preparation method of modified nano-silica

[0035] Nano-SiO2 was vacuum dried at 110°C for 2 hours to remove adsorbed water, and then cooled to room temperature for later use. The dried SiO2 was added to 600 mL of anhydrous ethanol and mechanically stirred at 400 rpm for 20 minutes.

[0036] In a separate beaker, prepare the pre-hydrolyzed solution of epoxy silane: 3.0 g γ-glycidoxypropyltrimethoxysilane + 150 mL ethanol + 12 mL deionized water. Adjust the pH to 4.5 ± 0.2 with glacial acetic acid. Stir magnetically at room temperature for 20–30 min to form a transparent solution. Slowly add the pre-hydrolyzed solution to the SiO2 ethanol dispersion system, heat to 78–80°C, and mechanically stir at 500 rpm for 2.0 h to complete the condensation of γ-glycidoxypropyltrimethoxysilane with the -Si–OH groups on the SiO2 surface, forming Si–O–Si anchoring bonds while retaining the epoxy end groups.

[0037] Cool to 35–40 °C and adjust the pH to 7.5–8.0 by adding triethylamine dropwise. Prepare the aminosilane pre-hydrolyzed solution: 1.0 g γ-aminopropyltriethoxysilane + 100 mL ethanol + 8 mL deionized water, and magnetically stir at room temperature for 15–20 min at pH 7.5–8.0. Slowly add this pre-hydrolyzed solution to the reaction system, heat to 70 °C, and continue the reaction with stirring at 400 rpm for 1.5 h to further condense γ-aminopropyltriethoxysilane with unreacted surface —Si–OH and immobilize —NH2 functional end groups.

[0038] After the reaction was completed, the mixture was cooled to room temperature, and the solid was collected by filtration. The solid was washed three times with 300 mL of a washing solution prepared with ethanol:water in a 9:1 ratio until no free silane was found in the filtrate. The filter cake was pre-dried in hot air at 80 °C for 1 h, and then transferred to a vacuum drying oven at 110 °C for 8–12 h to dry to constant weight. After drying, the powder was passed through a 200-mesh sieve to obtain grafted modified nano-silica powder.

[0039] II. Preparation of Surface-Activated Aramid Staple Fibers

[0040] Place the aramid staple fibers on a screen tray, lightly spray with anhydrous ethanol and vibrate briefly to remove dust, and allow the solvent to evaporate at room temperature. Dry with hot air at 80 °C for 1.0 h to remove surface moisture and residual solvent, cool to room temperature, depolymerize and loosen for later use. Spread the staple fibers evenly on the plasma treatment tray with a layer thickness ≤5 mm, evacuate to 0.3–0.6 mbar, introduce oxygen or air as the process gas, set the power to 120 W, and the treatment time to 3 min. After the treatment, purge with nitrogen and remove from the tray, immediately proceed to the next step to avoid surface aging.

[0041] Add 90.0 mL of ethyl acetate to a dry beaker, turn on magnetic stirring, and slowly add 10.0 g of IPDI trimer along the beaker wall, stirring continuously until completely dissolved and homogeneous. Add 0.05 g of dibutyltin dilaurate and continue stirring for 10 min until completely clear. Then filter through a 0.45 μm filter membrane and let stand for later use; this is the primer. Put the plasma-activated short fibers into a roller spray mixer and atomize them into the primer, ensuring even coverage of the fiber surface. During this process, intermittently stop spraying and agitate the fibers to prevent clumping, weighing them in real time until the fiber weight gain is 1.5 ± 0.3 wt%, at which point spraying is stopped. Allow the sprayed short fiber thin layer to cure for 12 h to allow the primer to form a film and react with the surface active sites. Dry at 60 °C in a ventilated environment for 1 h to remove residual solvent. Cool to room temperature, perform slight depolymerization, and sieve to obtain surface-activated aramid short fibers with an isocyanate primer coating.

[0042] III. Preparation of Wear-Resistant Sealing Strips

[0043] A wear-resistant sealing strip comprises the following raw materials in parts by weight: 100 parts elastomer matrix, 5 parts modified nano silica, 1 part surface-activated aramid short fiber, 1 part solid lubricating filler, 0.5 parts vulcanizing agent, 0.5 parts accelerator, 1 part antioxidant, and 0.5 parts processing aid.

[0044] The preparation method is as follows: Start the internal mixer (chamber type, closed, internal rotor type), preheat to 100 ± 2 °C, and set the rotor speed to 55 rpm. Add 1000 g of elastomer matrix evenly to the hopper in three batches, and mix for 1 min until it is completely plasticized. While the rotor is running continuously, add 50 g of modified nano-silica evenly, controlling the feeding time to about 30 s to avoid local accumulation. Continue mixing for 5 min, until the material temperature rises below 115 °C. After observing that the mixture is uniform and there are no obvious agglomerated particles, discharge the glue to obtain a uniform skeletal phase compound.

[0045] Return the skeletal phase rubber compound to the internal mixer, adjust the material temperature to 90 ± 2 °C, and reduce the rotor speed to 35 rpm. First, evenly sprinkle in 10 g of surface-activated aramid staple fiber and mix for 1 min to ensure that the fiber is initially dispersed and not cut. Then add 10 g of solid lubricant filler and continue mixing for 3 min until microscopic examination shows uniform fiber distribution and no obvious agglomeration of solid lubricant filler. Reduce the material temperature of the internal mixer to 75–80 °C, maintain the speed at 30 rpm, and add 5 g of vulcanizing agent sulfur, accelerator CBS, antioxidant 4010NA, and processing aid stearic acid in sequence, and continue mixing for 3 min until the auxiliaries are evenly dispersed. Delaminate the sheet and place it on a cooling table to cool to room temperature for later use.

[0046] The rubber compound is divided into an outer layer (wear-resistant layer) and an inner layer (flexible sealing layer) at a 1:1 mass ratio and fed separately into the two hoppers of a twin-screw co-extruder. Extrusion temperature settings: front section 80 °C, middle section 90 °C, die head 95 °C; screw speed 20–25 rpm. The outer layer compound formulation is adjusted to a Shore A hardness of 70; the inner layer compound formulation is adjusted to a Shore A hardness of 45 (controlled by adjusting fillers and softening oil). After extrusion molding, it immediately enters a hot air vulcanizing furnace at 170 °C for 8 minutes. After exiting the furnace, it is cooled to below 30 °C in a water cooling tank, shaped by a traction sizing machine, and cut to the designed length to obtain the wear-resistant sealing strip.

[0047] Example 2

[0048] The preparation methods for modified nano-silica and surface-activated aramid staple fibers are the same as in Example 1.

[0049] A wear-resistant sealing strip comprises the following raw materials in parts by weight: 100 parts elastomer matrix, 25 parts modified nano silica, 8 parts surface-activated aramid short fiber, 10 parts solid lubricating filler, 3 parts vulcanizing agent, 2 parts accelerator, 3 parts antioxidant, and 2 parts processing aid.

[0050] The preparation method of the above-mentioned wear-resistant sealing strip is the same as that in Example 1.

[0051] Example 3

[0052] The preparation methods for modified nano-silica and surface-activated aramid staple fibers are the same as in Example 1.

[0053] A wear-resistant sealing strip comprises the following raw materials in parts by weight: 100 parts elastomer matrix, 15 parts modified nano silica, 4.5 parts surface-activated aramid short fiber, 5.5 parts solid lubricating filler, 1.75 parts vulcanizing agent, 1.25 parts accelerator, 2 parts antioxidant, and 1.25 parts processing aid.

[0054] The preparation method of the above-mentioned wear-resistant sealing strip is the same as that in Example 1.

[0055] Comparative Example 1

[0056] The preparation method of surface-activated aramid staple fiber is the same as in Example 1.

[0057] A wear-resistant sealing strip comprises the following raw materials in parts by weight: 100 parts elastomer matrix, 15 parts unmodified nano silica, 4.5 parts surface-activated aramid short fiber, 5.5 parts solid lubricating filler, 1.75 parts vulcanizing agent, 1.25 parts accelerator, 2 parts antioxidant, and 1.25 parts processing aid.

[0058] The preparation method of the above-mentioned wear-resistant sealing strip is the same as that in Example 1.

[0059] Comparative Example 2

[0060] The preparation methods for modified nano-silica and surface-activated aramid staple fibers are the same as in Example 1.

[0061] A wear-resistant sealing strip comprises the following raw materials in parts by weight: 100 parts elastomer matrix, 15 parts unmodified nano silica, 4.5 parts surface-activated aramid short fiber, 1.75 parts vulcanizing agent, 1.25 parts accelerator, 2 parts antioxidant, and 1.25 parts processing aid.

[0062] The preparation method of the above-mentioned wear-resistant sealing strip is the same as that in Example 1.

[0063] Performance testing

[0064] 1. Wear resistance and friction properties test

[0065] (1) DIN wear test

[0066] According to ISO 4649 or DIN 53516 standards, the wear resistance of the abrasion-resistant sealing strips prepared in Examples 1-3 and Comparative Examples 1-2 was tested to quantitatively evaluate the abrasion resistance of each sample. The results are shown in Table 1 below.

[0067] Table 1. Wear results of wear-resistant sealing strips

[0068]

[0069] Table 1 shows that the DIN wear of Examples 1–3 was lower than that of Comparative Examples 1 and 2, with Example 2 showing the lowest wear (45 ± 2 mm³), which was about 38% lower than that of Comparative Example 1 without modified SiO2 and about 36% lower than that of Comparative Example 2 without PTFE. This is attributed to the grafted modified nano-SiO2 enhancing the skeleton strength and interfacial bonding force, the surface-activated aramid short fibers constructing the load-bearing network, and the solid lubricating filler forming a low-friction film layer during friction, all three of which synergistically reduced wear.

[0070] (2) Friction coefficient test

[0071] Using a reciprocating or rotary friction and wear testing machine, and referring to ASTM G133 standard, the dynamic and static coefficients of friction of the sealing strip when sliding in contact with a standard mating part (such as a steel plate) were measured. The test results are shown in Table 2 below.

[0072] Table 2 Friction coefficient results

[0073]

[0074]

[0075] As shown in Table 2, the static and dynamic friction coefficients of Examples 1–3 at different sliding distances were significantly lower than those of Comparative Examples 1 and 2, with Example 2 exhibiting the best performance (μ_s 0.45, μ_d 0.28), indicating its superior low-friction durability. Compared to Comparative Example 1 with unmodified SiO2, the grafted modified nano-SiO2 and surface-activated aramid short fibers constructed a high-strength and tough skeleton, reducing stress concentration in frictional contact. Compared to Comparative Example 2 without PTFE, the solid lubricant filler formed a dense and continuous low-friction film in situ during wear, effectively reducing the friction coefficient and maintaining stability. This result verifies the synergistic effect and long-term stability of the wear-resistant and low-friction mechanisms of this invention.

[0076] 2. Resilience and sealing foundation test

[0077] The abrasion-resistant sealing strips prepared in Examples 1-3 and Comparative Examples 1-2 were tested according to ASTM D395 / GB / T 7759, with compression set (C-set) measured at 70 ℃ for 22 h. Tensile properties were determined according to ASTM D412 / GB / T 528 for tensile strength and elongation at break, and tear strength according to ASTM D624 / GB / T 529. The hardness of the outer and inner layers was measured according to ASTM D2240 / GB / T 531.1. The results are shown in Table 3 below.

[0078] Table 3. Test results of resilience and sealing foundation

[0079] As shown in Table 3, the wear-resistant sealing strip of the present invention is significantly superior to the comparative examples in terms of resilience, sealing retention, and mechanical strength. The compression set of Examples 1–3 is 12%–15%, significantly lower than that of Comparative Examples 1–2, with a reduction of 25%–40%, verifying that the skeleton network synergistically constructed by modified nano-silica and surface-activated aramid short fibers can effectively suppress stress relaxation and maintain sealing performance over a long period. Furthermore, the examples show higher tensile strength (≥14 MPa), elongation at break (≥350%), and tear strength (≥40 kN / m) than the comparative examples, demonstrating that a dual interfacial bonding mechanism of chemical bonds + hydrogen bonds is formed between the reinforcing phase and the EPDM matrix, which not only improves wear resistance but also enhances overall toughness and impact resistance.

[0080] Furthermore, the outer layer hardness (approximately 70A) and inner layer hardness (45A) of the embodiment exhibit a clear gradient distribution, which aligns with the expected gradient structure design and facilitates the functional division of the outer layer for wear resistance and the inner layer for flexible sealing. In contrast, the gradient disappears in the comparative example (the hardness of the inner and outer layers is similar), making it difficult to balance wear resistance and sealing adaptability. In summary, the wear-resistant sealing strip of the embodiment is significantly superior to the comparative example in terms of resilience, seal retention, and mechanical strength.

[0081] 3. Low-temperature rebound rate test

[0082] Referring to ASTM D1329 or GB / T 7758, the specimen was stretched along the gauge length to twice its original length (100% constant elongation) at 23 °C and held for 10 min. While maintaining constant elongation, the specimen was immersed in a cryogenic bath, cooled to −70 °C, and held at that temperature for 10 min to allow stress freezing. The specimen was then quickly transferred to a −70 °C air environment in preparation for unclamping and measurement. After unclamping, the temperature was immediately increased at a rate of 2 °C / min. The curve of the specimen's shrinkage length versus temperature was continuously recorded, and the relative shrinkage R(T) and characteristic temperature point were calculated. A lower TR value indicates that the material can recover its elasticity at a lower temperature, indicating better low-temperature flexibility. The results are shown in Table 4 below.

[0083] Table 4 Low-temperature rebound results

[0084] As shown in Table 4, the TR10, TR30, TR50, and TR70 values ​​of Examples 1–3 are significantly lower than those of Comparative Examples 1 and 2, especially in Example 2, where TR10 is as low as −45 °C, a decrease of approximately 17–19 °C compared to the comparative examples. This indicates that the material system of the present invention can still rapidly recover its elasticity under extremely low temperature conditions. This is attributed to the synergistic effect of the modified nano-SiO2 reinforced skeleton structure and the uniformly distributed PTFE lubricant introduced in the invention: the former reduces the low-temperature glass transition constraint of the chain segments, while the latter reduces low-temperature internal friction and crack initiation, making it easier for the chain segments to release stress and return to their original shape during the heating process. This significantly improves low-temperature flexibility and resilience, and broadens the application range of the sealing strip in cold and extreme environments.

[0085] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0086] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A wear-resistant sealing strip, characterized in that, The raw materials include the following parts by weight: 100 parts elastomer matrix, 5-25 parts modified nano silica, 1-8 parts surface-activated aramid short fiber, 1-10 parts solid lubricating filler, 0.5-3 parts vulcanizing agent, 0.5-2 parts accelerator, 1-3 parts antioxidant, and 0.5-2 parts processing aid. The modified nano-silica surface is grafted with a bifunctional silane coupling agent containing epoxy and amino groups. The surface-activated aramid short fibers are plasma-treated and coated with an isocyanate base coating. The solid lubricating filler is selected from one or more of polytetrafluoroethylene micro powder, graphite, hexagonal boron nitride, or molybdenum disulfide.

2. The wear-resistant sealing strip according to claim 1, characterized in that, The preparation method of modified nano-silica includes the following steps: S101: Nano-silica is dispersed in anhydrous alcohol solvent and mixed with silane coupling agents containing epoxy and amino groups to prepare a coupling pretreatment solution. S102: The coupling pretreatment liquid is added to the nano-silica dispersion system, and a grafting condensation reaction is carried out under stirring and heating conditions to obtain a modified slurry; S103: The modified slurry is subjected to solid-liquid separation, and is washed, dried and depolymerized and sieved in sequence to obtain grafted modified nano-silica.

3. The wear-resistant sealing strip according to claim 1, characterized in that, The method for preparing the surface-activated aramid staple fiber includes the following steps: S201: Spread aramid staple fibers evenly on the worktable of the plasma treatment device, set appropriate atmosphere and power conditions, and turn on the plasma source to perform all-round activation treatment on the fiber surface. S202: Take out the plasma-activated aramid short fibers and immediately place them in the spraying station. Spray the prepared isocyanate solution evenly onto the fiber surface through the nozzle. S203: Place the sprayed aramid staple fiber in a clean and dry environment, let it stand and cure at room temperature until the base coating is completely formed, and keep the fiber in a dispersed state to finally obtain surface-activated aramid staple fiber with a base coating.

4. The wear-resistant sealing strip according to claim 1, characterized in that, The elastomer matrix is ​​one or more of EPDM rubber, thermoplastic vulcanized rubber, silicone rubber, chloroprene rubber, or nitrile rubber.

5. The wear-resistant sealing strip according to claim 1, characterized in that, The particle size of the solid lubricating filler is 0.5–10 μm.

6. The wear-resistant sealing strip according to claim 1, characterized in that, The vulcanizing agent is di-tert-butyl peroxide, sulfur, or a combination thereof, and the accelerator is N-cyclohexyl-2-benzothiazole sulfenamide, dithiocarbamates, or a combination thereof.

7. The wear-resistant sealing strip according to claim 1, characterized in that, The antioxidant is selected from antioxidant 4010NA, antioxidant RD, or a combination thereof, and the processing aid is selected from paraffin wax, stearic acid, polyethylene glycol, or a combination thereof.

8. A method for preparing a wear-resistant sealing strip, wherein the wear-resistant sealing strip is as described in claims 1-7, characterized in that, Includes the following steps: S1. Weigh the elastomer matrix and the modified nano silica together and put them into a mixer. Stir and mix at a temperature of 90-110 ℃ for 4-6 minutes to make the nano silica uniformly dispersed and form a preliminary skeleton phase with the matrix. S2. Add surface-activated aramid short fibers and solid lubricating fillers to the skeleton phase, control the rotor speed to 30-40 rpm and the temperature to 80-100 ℃, and perform low-shear mixing for 3-5 minutes; add vulcanizing agent, accelerator, antioxidant and processing aid to the mixture in sequence, and continue mixing at 70-90 ℃ for 2-4 minutes; S3. The mixed rubber compound is co-extruded in two layers using a twin-screw extruder or parallel twin-unit extrusion molding process. The total content of grafted modified nano-silica, surface-activated aramid short fibers and solid lubricating fillers in the outer layer is controlled to be more than 1.5 times higher than that in the inner layer. After extrusion, it is vulcanized in hot air or salt bath on a continuous vulcanization production line at a vulcanization temperature of 160-190 ℃ for 5-12 minutes. Finally, it is cooled, cut and shaped to obtain the finished wear-resistant sealing strip.

9. The method for preparing a wear-resistant sealing strip according to claim 8, characterized in that, The outer layer of the double-layer co-extrusion molding has a Shore A hardness of 70-85, and the inner layer has a Shore A hardness of 45-60. The total content of grafted modified nano-silica, surface-activated aramid short fibers and solid lubricant fillers in the outer layer is higher than that in the inner layer.

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