High-pressure wear-resistant valve rubber

Abstract

The invention provides a high-pressure wear-resistant valve rubber. The valve rubber is prepared from the following raw materials in parts by weight: 100 parts of a polyurethane prepolymer, 20 to 30 parts of a chain extender, 12 to 18 parts of a polycaprolactone coated boron nitride / molybdenum disulfide composite material and 0.5 to 2 parts of an antioxidant. Wherein the polycaprolactone coated boron nitride / molybdenum disulfide composite material is obtained by polymerizing an amino silane coupling agent modified boron nitride / molybdenum disulfide composite material, triethyl aluminum and epsilon-caprolactone in an organic solvent at 35-45 DEG C in an inert atmosphere. A polycaprolactone-coated boron nitride / molybdenum disulfide composite material is used as a filler, and boron nitride / molybdenum disulfide as an inner core forms a synergistic structure of a reinforced substrate and a lubricating surface layer, so that high-pressure load bearing and friction coefficient reduction are facilitated; and the polycaprolactone flexible shell layer is compatible with the matrix, so that the filler is uniformly dispersed in the matrix.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane materials technology, specifically relating to a high-pressure wear-resistant valve rubber. Background Technology

[0002] As the core dynamic sealing element of the hydraulic end of a plunger pump in oil extraction, the performance of the valve directly determines the efficiency, operational stability, and maintenance cost of the entire pumping system. In oilfield operations such as water injection and fracturing, plunger pumps need to operate continuously under extreme high pressures (typically reaching 40-150 MPa, or even higher).

[0003] Polyurethane (PU) elastomers, due to their unique microphase separation structure, possess excellent mechanical strength, high elasticity, outstanding oil and solvent resistance, and good basic wear resistance, and have long been considered one of the ideal matrix materials for manufacturing valves. However, while traditional polyurethane valves perform adequately under moderate operating conditions, they are insufficient to handle the aforementioned high-pressure conditions. Extremely high contact pressures lead to significant stress concentration within the material, particularly at the interface between the hard and soft micro-regions. Under the reciprocating impact of a plunger pump, which can be tens or even hundreds of times per minute, this alternating stress easily induces fatigue cracking of the polyurethane hard-segment microcrystals, leading to the formation of microcracks. As these cracks propagate and connect, macroscopic fatigue spalling eventually occurs. These spalling debris particles mix in the fluid medium, transforming into abrasives and causing severe abrasive wear, further exacerbating surface damage and creating a vicious cycle. Secondly, the high-pressure friction process generates a large amount of heat, and polyurethane materials generally have poor thermal conductivity, making it difficult for the heat to dissipate quickly, resulting in a sharp increase in the local temperature of the sealed contact area. High temperatures not only accelerate the thermo-oxidative aging process of polyurethane molecular chains, causing the main chain or side chains to break and significantly reducing the material's hardness, strength, and elastic modulus, but also soften the material surface, making it more susceptible to wear and deformation, thus losing its sealing function.

[0004] To improve the wear resistance and high-pressure deformation resistance of polyurethane elastomers, existing technologies typically modify the polyurethane matrix by adding inorganic fillers. However, inorganic fillers have poor interfacial compatibility with the polyurethane matrix, making it difficult to disperse uniformly within the matrix. Furthermore, the interfacial bonding between the two is weak, and the fillers are prone to peeling off from the matrix under external forces. This not only fails to effectively improve the wear resistance and creep resistance of polyurethane elastomers under high-pressure conditions but may also lead to a decrease in material toughness due to filler agglomeration, further shortening the service life of valves. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides a high-pressure wear-resistant valve rubber sheet.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A high-pressure wear-resistant valve rubber, by weight, comprises the following raw materials: 100 parts polyurethane prepolymer, 20-30 parts chain extender, 12-18 parts polycaprolactone-coated boron nitride / molybdenum disulfide composite material, and 0.5-2 parts antioxidant; wherein the polycaprolactone-coated boron nitride / molybdenum disulfide composite material is obtained by polymerizing an aminosilane coupling agent-modified boron nitride / molybdenum disulfide composite material, triethylaluminum, and ε-caprolactone in an organic solvent under an inert atmosphere at 35-45°C.

[0007] Preferably, the raw materials, by weight, comprise: 100 parts polyurethane prepolymer, 23-25 ​​parts chain extender, 12-14 parts polycaprolactone-coated boron nitride / molybdenum disulfide composite material, and 0.5-0.7 parts antioxidant. The mass ratio of the aminosilane coupling agent-modified boron nitride / molybdenum disulfide composite material, triethylaluminum, and ε-caprolactone is 1:(0.04-0.08):(3-10). Preferably, the mass ratio of the aminosilane coupling agent-modified boron nitride / molybdenum disulfide composite material, triethylaluminum, and ε-caprolactone is 1:0.06:5.

[0008] The aminosilane coupling agent modified boron nitride / molybdenum disulfide composite material is prepared by a commonly used silane coupling agent modification method. Preferably, the aminosilane coupling agent modified boron nitride / molybdenum disulfide composite material is prepared by a method comprising the following steps: dispersing 1 part by weight of the boron nitride / molybdenum disulfide composite material in 80-120 parts by weight of anhydrous xylene; adding 0.01-0.03 parts by weight of 3-(2-aminoethyl)aminopropyltrimethoxysilane at an inert atmosphere and a reflux temperature of 115-125°C; reacting for 2-4 hours; and then washing with ethanol and drying to obtain the final product. Preferably, the 3-(2-aminoethyl)aminopropyltrimethoxysilane is 0.02 parts by weight.

[0009] The boron nitride / molybdenum disulfide composite material is prepared by a closed hydrothermal reaction of boron nitride nanosheets, sodium molybdate dihydrate, thiourea, and hydroxylamine hydrochloride in water at pH 1-2 and temperature 225-235℃ for 23-25 ​​hours, wherein the pH is adjusted with 37% concentrated hydrochloric acid.

[0010] The mass ratio of boron nitride nanosheets, sodium molybdate dihydrate, thiourea, and hydroxylamine hydrochloride is (0.1-0.2):(0.3-0.4):(0.4-0.6):(0.15-0.25). Preferably, the mass ratio of boron nitride nanosheets, sodium molybdate dihydrate, thiourea, and hydroxylamine hydrochloride is 0.1:0.36:0.45:0.15.

[0011] The polyurethane prepolymer is polymerized from polycaprolactone and toluene diisocyanate. During polymerization, the mass ratio of polycaprolactone to toluene diisocyanate (TDI) is 100:(15–26). Preferably, the mass ratio of polycaprolactone to TDI is 100:(24–26). During the preparation of this prepolymer, the degree of reaction is controlled to ensure that the content of free isocyanate groups (-NCO) in the final prepolymer is 6-6.2 wt%, so as to ensure that the subsequent reaction with the chain extender forms an elastomer with a suitable crosslinked network structure.

[0012] Preferably, the high-pressure wear-resistant valve rubber of the present invention is prepared by a method comprising the following steps: (11) Under an inert atmosphere, the polyurethane prepolymer is heated to 110–120°C, vacuum dehydrated, and then polycaprolactone-coated boron nitride / molybdenum disulfide composite material and antioxidant are added and stirred evenly to obtain a prepolymer / filler mixture. (2) Add melt chain extender to the prepolymer / filler mixture, stir and degas under vacuum for 3-5 minutes, and then quickly pour it into a mold preheated to 100-110℃. First, cure at 100-110℃ for 14-18 hours, and then demold and vulcanize again at 100℃ for 6-10 hours to obtain the high-pressure wear-resistant valve rubber.

[0013] Preferably, the chain extender used is a commonly used chain extender in TDI systems. More preferably, the chain extender is 3,3-dichloro-4,4-diaminodiphenylmethane (MOCA), 1,4-butanediol (BDO), etc. More preferably, the chain extender is 3,3-dichloro-4,4-diaminodiphenylmethane.

[0014] Preferably, the antioxidant is a commonly used antioxidant in the prior art, such as hindered phenolic antioxidants, phosphite antioxidants, or a combination of both.

[0015] This application has the following beneficial effects: This invention employs a polycaprolactone-coated boron nitride / molybdenum disulfide composite material as a functional filler to construct a precise structural design of a "rigid core-flexible shell." The core is a boron nitride / molybdenum disulfide composite material, with molybdenum disulfide grown on the surface of boron nitride nanosheets via a hydrothermal method, forming a synergistic heterogeneous structure of a "rigid reinforced substrate + lubricating surface layer." Boron nitride, acting as a "skeleton," effectively bears loads under high pressure due to its extremely high hardness and modulus, inhibiting plastic deformation and creep in the polyurethane matrix. Molybdenum disulfide, utilizing its easy interlayer slippage, provides continuous and effective solid lubrication at the friction interface, significantly reducing the coefficient of friction and minimizing frictional heat generation. Simultaneously, the introduction of molybdenum disulfide connects isolated boron nitride layers, constructing a continuous thermal conductivity pathway within the composite material. The large specific surface area of ​​molybdenum disulfide rapidly absorbs heat from the friction interface, and the highly thermally conductive boron nitride skeleton efficiently conducts and disperses the heat, thus achieving an efficient generation-absorption-conduction-dissipation mechanism for frictional heat, effectively avoiding material performance degradation caused by localized overheating.

[0016] The molecular chain segments of the polycaprolactone flexible shell are highly similar in chemical structure to the polycaprolactone-based polyurethane prepolymer used in this invention, exhibiting excellent compatibility. They can form a strong physical bond with the soft segments of the polyurethane matrix through molecular chain interdiffusion, entanglement, and hydrogen bonding. Simultaneously, during the casting process, the molten polycaprolactone shell and the polyurethane matrix can effectively wet each other. This allows the composite filler to be uniformly and stably dispersed in the polyurethane matrix, achieving both uniform dispersion and strong interfacial bonding.

[0017] The modulus gradient transition layer formed by the filler in the polyurethane matrix, consisting of a rigid core, a flexible shell, and the polyurethane matrix, enables efficient stress transfer and buffering. This makes the material less prone to interfacial peeling and crack propagation when subjected to high-pressure impact, significantly improving the high-pressure load-bearing capacity and impact wear resistance of the rubber. Detailed Implementation

[0018] The present application will be further described in detail below with reference to the embodiments.

[0019] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0020] The boron nitride nanosheets used in this application were prepared by exfoliating hexagonal boron nitride powder using liquid-phase ultrasonication. The specific process was as follows: 2 g of 1-2 μm boron nitride powder was added to 400 mL of isopropanol / water (volume ratio 1:1), followed by ultrasonication (240 W, 40 kHz) for 48 h. The mixture was then centrifuged at 3000 r / min for 22 min, and the supernatant was collected. The supernatant was then centrifuged at 12000 r / min for 15 min, and the precipitate was collected. Finally, the precipitate was vacuum dried at 60 °C for 12 h to obtain boron nitride nanosheets. The boron nitride / molybdenum disulfide composite material obtained by repeated experiments was collected and combined for later use.

[0021] The boron nitride / molybdenum disulfide composite material used in this application was prepared by the following method: 0.1 g of boron nitride nanosheets were dispersed in 30 mL of deionized water and ultrasonically dispersed for 1 h to obtain an aqueous dispersion of boron nitride nanosheets; under continuous stirring at 90 °C, 0.36 g of sodium molybdate dihydrate, 0.15 g of hydroxylamine hydrochloride, 0.45 g of thiourea, and 0.25 mL of concentrated hydrochloric acid (37 wt%) were added to 20 mL of distilled water and stirred for 30 min until completely dissolved to obtain a molybdenum disulfide precursor solution; the molybdenum disulfide precursor solution was added to the boron nitride nanosheet dispersion and transferred to a 100 mL polytetrafluoroethylene liner in a hydrothermal reactor. The pH of the reaction system was approximately 1. The reactor was sealed and reacted at 230 °C for 24 h. After the reaction, the solid product was collected by centrifugation, washed repeatedly with distilled water, and then vacuum dried at 60 °C for 12 h to obtain the boron nitride / molybdenum disulfide composite material. Repeat the experiment multiple times to collect and combine the obtained boron nitride / molybdenum disulfide composite materials for later use.

[0022] The polycaprolactone-coated boron nitride / molybdenum disulfide composite materials used in the following examples were prepared using the following methods: (1) Modification with silane coupling agent Under a nitrogen atmosphere, 1 g of boron nitride / molybdenum disulfide composite material dried under vacuum at 120 °C for 4 h was added to a three-necked flask containing 100 mL of anhydrous xylene (with 0.5 g of 3 Å molecular sieve). The temperature was raised to 120 °C and refluxed. Then, a silane coupling agent dispersion formed by dissolving 0.02 g of 3-(2-aminoethyl)aminopropyltrimethoxysilane in 2 mL of anhydrous ethanol was added dropwise over 20 min. The mixture was then refluxed for 3 h. After the reaction was completed, the mixture was filtered, and the filter cake was dried under vacuum at 60 °C for 2 h. Then, it was extracted with anhydrous ethanol at 70 °C for 2 h to remove physically adsorbed silane. Finally, it was dried under vacuum at 80 °C for 4 h to obtain the silane coupling agent modified boron nitride / molybdenum disulfide composite material.

[0023] (2) Polycaprolactone coating 0.50 g of aminosilane coupling agent-modified boron nitride / molybdenum disulfide composite material was placed in a 50 mL round-bottom flask, 20 mL of dry THF was added, and after attaching a condenser, the temperature was raised to 70–75 °C in an oil bath. The first 10 mL of THF-water azeotropic fraction was discarded by atmospheric distillation, and an equal amount of fresh dry THF was added and cooled to 40 °C. Under nitrogen protection, 0.03 g of triethylaluminum was added for activation for 30 min, followed by the addition of 2.5 g of ε-caprolactone. The reaction was carried out at 40 °C for 6 h, and the reaction was terminated with 0.5 mL of methanol. 5 mL of 0.1 M HCl was added to remove aluminum, and the precipitate was collected by centrifugation. The precipitate was washed once with THF / heptane (volume ratio 1:3) and dried under vacuum at 50 °C for 12 h to obtain polycaprolactone-coated boron nitride / molybdenum disulfide composite material.

[0024] Example 1 The high-pressure wear-resistant valve rubber sheet of this embodiment is made from the following raw materials in parts by weight: 100g of polyurethane prepolymer, 24g of 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA) chain extender, 13g of polycaprolactone-coated boron nitride / molybdenum disulfide composite material, and 0.7g of antioxidant 1010 / 168 (mass ratio 1:1).

[0025] Prepared by the following method: Prepolymer preparation: 100g of polycaprolactone-1000 (hydroxyl value approximately 110mgKOH / g) was added to a reactor and dehydrated under vacuum at 120℃ for 1h. After the system was fully dehydrated, the temperature was lowered to 80℃ under a nitrogen atmosphere, and 24.5g of toluene diisocyanate (TDI80) was added dropwise over a period of 30min. Then the temperature was raised to 85℃ and reacted for 2h. During the reaction, the free -NCO content was measured and heating was stopped when it reached 6.2wt%, thus terminating the reaction and obtaining a polyurethane prepolymer. The prepolymer was degassed under a vacuum of ≤5mbar for 30min, sealed in a sample bottle, and stored under a protective gas atmosphere.

[0026] Preparation of valve rubber: Under a nitrogen atmosphere, the polyurethane prepolymer is vacuum dehydrated at 110℃ and ≤5mbar for 1h; then, pre-dried polycaprolactone-coated boron nitride / molybdenum disulfide composite material and antioxidant are added, and stirred at 600r / min for 5min to obtain a prepolymer / filler mixture; then, molten MOCA is added to the prepolymer / filler mixture, and the mixture is stirred at high speed and degassed at ≤5mbar vacuum for 3min, and immediately poured into a mold preheated to 110℃ and coated with a release agent; first, it is cured at 110℃ for 18h, then demolded and then vulcanized again at 110℃ for 10h, and cooled in the furnace to obtain high-pressure wear-resistant valve rubber.

[0027] Example 2 The high-pressure wear-resistant valve rubber sheet of this embodiment is made from the following raw materials in parts by weight: 100g of polyurethane prepolymer, 25g of MOCA chain extender, 12g of polycaprolactone-coated boron nitride / molybdenum disulfide composite material, and 0.5g of antioxidant 1010.

[0028] The preparation method is as follows: Prepolymer preparation: 100g of polycaprolactone-1000 (hydroxyl value approximately 110mgKOH / g) was added to a reactor and dehydrated under vacuum at 120℃ for 1h. After the system was fully dehydrated, the temperature was lowered to 80℃ under a nitrogen atmosphere, and 24g of toluene diisocyanate (TDI80) was added dropwise over a controlled dropwise time of 30min. Then the temperature was raised to 85℃ and reacted for 2h. During the reaction, a sample was taken to measure the free -NCO content, and heating was stopped to terminate the reaction, yielding a polyurethane prepolymer. The prepolymer was degassed under a vacuum of ≤5mbar for 30min, sealed in a sample bottle, and stored under a protective gas atmosphere.

[0029] The preparation steps for the valve rubber are the same as in Example 1.

[0030] Example 3 The high-pressure wear-resistant valve rubber sheet of this embodiment is made from the following raw materials in parts by weight: 100g of polyurethane prepolymer, 23g of MOCA chain extender, 14g of polycaprolactone-coated boron nitride / molybdenum disulfide composite material, and 0.6g of antioxidant 168.

[0031] The preparation method is as follows: Prepolymer preparation: 100g of polycaprolactone-1000 (hydroxyl value approximately 110mgKOH / g) was added to a reactor and dehydrated under vacuum at 120℃ for 1h. After the system was fully dehydrated, the temperature was lowered to 80℃ under a nitrogen atmosphere, and 26g of toluene diisocyanate (TDI80) was added dropwise over a time of 30min. Then the temperature was raised to 85℃ and reacted for 2h. During the reaction, a sample was taken to measure the free -NCO content, and heating was stopped to terminate the reaction, yielding a polyurethane prepolymer. The prepolymer was degassed under a vacuum of ≤5mbar for 30min, sealed in a sample bottle, and stored under a protective gas atmosphere.

[0032] The preparation steps for the valve rubber are the same as in Example 1.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that the filler used is a boron nitride / molybdenum disulfide composite material.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is that the filler used is 6 parts polycaprolactone-coated boron nitride nanosheets and 7 parts silane coupling agent-modified molybdenum disulfide.

[0035] The specific preparation process of polycaprolactone-coated boron nitride nanosheets is the same as that of polycaprolactone-coated boron nitride / molybdenum disulfide composite material, except that the boron nitride / molybdenum disulfide composite material is replaced with boron nitride nanosheets.

[0036] The preparation process of silane coupling agent modified molybdenum disulfide is as follows: 2g of molybdenum disulfide is ultrasonically dispersed in 100mL of 80wt% ethanol aqueous solution, and then 0.004g of 3-(2-aminoethyl)aminopropyltrimethoxysilane is added. The mixture is stirred at room temperature for 2h, and then filtered, washed and dried to obtain silane coupling agent modified molybdenum disulfide.

[0037] Comparative Example 3 The difference between this comparative example and Example 1 is that the filler is a polybutyl acrylate-coated boron nitride / molybdenum disulfide composite material.

[0038] The preparation method of polybutyl acrylate-coated boron nitride / molybdenum disulfide composite material is as follows: (1) Bromoacyl bromide modification: 1g of dry boron nitride / molybdenum disulfide composite material and 30mL of dry toluene were added to a 100mL three-necked flask, nitrogen gas was introduced, and the temperature was lowered to 0℃ in an ice-water bath; a mixture of triethylamine (2mL) and 2-bromoisobutyryl bromide (0.8g) and 5mL of dry toluene was added in sequence, and the mixture was added dropwise over 30min; stirring was continued at 0℃ for 3h, and then the ice bath was removed, and the reaction was allowed to proceed at room temperature for 12h; after the reaction was completed, the mixture was centrifuged, washed 3 times with toluene, and dried under vacuum at 60℃ for 12h to obtain bromine-modified boron nitride / molybdenum disulfide composite material.

[0039] (2) Polybutyl acrylate shell polymerization: In a glove box, 0.50 g of bromine-modified boron nitride / molybdenum disulfide composite material was placed in a 50 mL Schlenk flask, and dried N,N-dimethylformamide (DMF, 20 mL), n-butyl acrylate (2.5 g), ferric chloride hexahydrate (29 mg), triphenylphosphine (212 mg), and ethyl α-bromoisobutyrate initiator (45 μL) were added sequentially; the mixture was sonicated for 10 min to ensure uniform dispersion. After sealing, the mixture was evacuated three times, and 2.5 mL of cuprous chloride (0.53 g) in DMF solution was injected. Polymerization was carried out in an oil bath at 40 °C for 12 h. After the reaction was completed, tetrahydrofuran (20 mL) was added for dilution, and the mixture was centrifuged (8000 rpm, 10 min), washed three times with tetrahydrofuran / methanol (1:3, v / v), and vacuum dried at 50 °C for 12 h to obtain the polybutyl acrylate-coated boron nitride / molybdenum disulfide composite material.

[0040] Experimental Example 1 This test example examines the service life of the valves in Examples 1-3 and Comparative Examples 1-3 under different working pressures.

[0041] The test method is as follows: The valve was installed on a self-designed "plunger pump hydraulic end simulation test bench" with fracturing fluid containing ≤40% sand and the medium temperature controlled at 30-40℃. Under the action of spring and liquid pressure, the valve made vertical reciprocating motion, impacting the valve seat. The frequency of the reciprocating motion was 2Hz. Three sets of parallel operations were conducted at six working pressure levels: 40, 60, 80, 100, 120, and 140MPa. The failure criterion was that leakage ≥0.5mL / min or surface cracks ≥1mm appeared at each pressure level. The average lifespan of the three sets was taken.

[0042] The test results are as follows.

[0043] Comparative Example 1 directly used boron nitride / molybdenum disulfide composite material as filler, which lacked flexible shell modification, resulting in poor compatibility and uneven dispersion of the filler with the polyurethane matrix. Under high pressure, it was prone to interfacial peeling, resulting in a service life of only 40 hours at 100 MPa. In contrast, Example 1 reached 58 hours, which fully demonstrates that the synergistic effect of the shell and the core can effectively avoid filler agglomeration failure and enhance high pressure bearing capacity and wear resistance.

[0044] Comparative Example 2 used a mixed filler of boron nitride nanosheets coated with polycaprolactone and molybdenum disulfide modified with silane coupling agent. The two were only physically mixed and could not form a continuous reinforcement-lubrication-thermal conduction network. The service life was only 63 hours at 80 MPa, which was lower than 72 hours in Example 1. This shows that the load-bearing role of boron nitride and the lubrication and thermal conduction role of molybdenum disulfide in the integrated core need to work together to achieve a significant improvement in service life.

[0045] Comparative Example 3 uses a boron nitride / molybdenum disulfide composite material coated with polybutyl acrylate. Although its service life under high pressure is better than that of Comparative Example 1, the polybutyl acrylate flexible layer has poor compatibility with the polyurethane matrix, insufficient interfacial bonding force, and insufficient modulus matching, which leads to a decrease in stress transfer efficiency. Therefore, its service life is lower than that of Examples 1-3 which use a polycaprolactone flexible layer.

[0046] Experimental Example 2 This experiment tested the abrasion resistance of the valve rubber sheets of Examples 1-3 and Comparative Examples 1-3 (under a working pressure of 140 MPa). The specific test methods and test results are shown in the table below.

[0047] The test results show that the Akron wear rate of Examples 1-3 is only 0.025-0.028 cm³ / 1.61 km, which is lower than that of the comparative example. This indicates that the polycaprolactone flexible coating layer effectively improves the uniformity of filler dispersion and the interfacial bonding force between the filler and the matrix, significantly enhancing the wear resistance of the material.

[0048] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A high-pressure wear-resistant valve rubber sheet, characterized in that, By weight, the raw materials include: 100 parts polyurethane prepolymer, 20-30 parts chain extender, 12-18 parts polycaprolactone-coated boron nitride / molybdenum disulfide composite material, and 0.5-2 parts antioxidant. The polycaprolactone-coated boron nitride / molybdenum disulfide composite material is obtained by polymerizing an aminosilane coupling agent-modified boron nitride / molybdenum disulfide composite material, triethylaluminum, and ε-caprolactone in an organic solvent under an inert atmosphere at 35-45°C.

2. The high-pressure wear-resistant valve rubber sheet according to claim 1, characterized in that, The raw materials, by weight, include: 100 parts polyurethane prepolymer, 23-25 ​​parts chain extender, 12-14 parts polycaprolactone-coated boron nitride / molybdenum disulfide composite material, and 0.5-0.7 parts antioxidant.

3. The high-pressure wear-resistant valve rubber according to claim 1 or 2, characterized in that, The mass ratio of the aminosilane coupling agent modified boron nitride / molybdenum disulfide composite material, triethylaluminum, and ε-caprolactone is 1:(0.04-0.08):(3-10).

4. The high-pressure wear-resistant valve rubber sheet according to claim 3, characterized in that, The aminosilane coupling agent modified boron nitride / molybdenum disulfide composite material is prepared by a method including the following steps: 1 part by weight of the boron nitride / molybdenum disulfide composite material is dispersed in 80-120 parts by weight of anhydrous xylene, and 0.01-0.03 parts by weight of 3-(2-aminoethyl)aminopropyltrimethoxysilane is added under an inert atmosphere and at a reflux temperature of 115-125°C. After reacting for 2-4 hours, the mixture is filtered, washed with ethanol, and dried to obtain the final product.

5. The high-pressure wear-resistant valve rubber sheet according to claim 4, characterized in that, The boron nitride / molybdenum disulfide composite material is prepared by a closed hydrothermal reaction of boron nitride nanosheets, sodium molybdate dihydrate, thiourea, and hydroxylamine hydrochloride in water at pH 1-2 and temperature 225-235℃ for 23-25 ​​hours, wherein the pH is adjusted by concentrated hydrochloric acid with a mass fraction of 37%.

6. The high-pressure wear-resistant valve rubber according to claim 5, characterized in that, The mass ratio of boron nitride nanosheets, sodium molybdate dihydrate, thiourea, and hydroxylamine hydrochloride is (0.1-0.2):(0.3-0.4):(0.4-0.6):(0.15-0.25).

7. The high-pressure wear-resistant valve rubber according to claim 1 or 2, characterized in that, The polyurethane prepolymer is polymerized from polycaprolactone and toluene diisocyanate.

8. The high-pressure wear-resistant valve rubber according to claim 7, characterized in that, The mass ratio of polycaprolactone to toluene diisocyanate is 100:(15–26).

9. The high-pressure wear-resistant valve rubber according to claim 1 or 2, characterized in that, Prepared by a method including the following steps: (1) Under an inert atmosphere, the polyurethane prepolymer is heated to 110–120°C, vacuum dehydrated, and then polycaprolactone-coated boron nitride / molybdenum disulfide composite material and antioxidant are added and stirred evenly to obtain a prepolymer / filler mixture. (2) Add melt chain extender to the prepolymer / filler mixture, stir and degas under vacuum for 3-5 minutes, and then quickly pour it into a mold preheated to 100-110℃. First, cure at 100-110℃ for 14-18 hours, and then demold and vulcanize again at 100℃ for 6-10 hours to obtain the high-pressure wear-resistant valve rubber.

10. The high-pressure wear-resistant valve rubber according to claim 1 or 2, characterized in that, The chain extender is 1,4-butanediol and / or 3,3-dichloro-4,4-diaminodiphenylmethane; the antioxidant is a hindered phenolic antioxidant, a phosphite antioxidant, or a combination of both.

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