A rubber composite for a power transmission belt and a method of making the same

Abstract

The present application relates to the technical field of rubber composition, in particular to a rubber composite material for drive belt and a preparation method thereof.The present application overcomes the problems of poor heat aging resistance and weak interface bonding of hydrogenated nitrile rubber composition.The rubber composite material of the present application is composed of a hydrogenated nitrile rubber main matrix, a reactive liquid rubber dispersed phase containing a heat-conducting medium, and aramid fibers with surface grafted active functional groups; a hybrid masterbatch is constructed by using liquid phase pre-dispersion technology, and a segmented mixing process is combined to promote in-situ polymerization of active crosslinking aids and chemical crosslinking between each polymer phase and the reinforcing phase; by constructing a "fiber-rubber" chemical bonding interface in the system and constructing an efficient heat conduction network, the technical problems of poor heat aging resistance of the rubber matrix and easy peeling of the multi-phase interface are effectively solved, and the service life and thermodynamic stability of the hydrogenated nitrile composition under high temperature and high dynamic conditions are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of rubber composition technology, specifically to a rubber composite material for transmission belts and its preparation method. Background Technology

[0002] Hydrogenated nitrile butadiene rubber (HNBR), as a high-performance specialty elastomer, possesses excellent heat resistance, oil resistance, and mechanical properties due to its saturated carbon backbone structure, making it the preferred matrix material for manufacturing high-performance power transmission belts. However, with the increasing demands on the dynamic modulus and fatigue threshold of materials in applications, more stringent requirements are being placed on the performance of rubber compositions. Existing HNBR matrix formulations have revealed significant limitations in terms of microstructure and thermodynamic stability.

[0003] Firstly, there is the issue of heat aging resistance in rubber materials. Under continuous high-frequency dynamic compression deformation, the rubber macromolecular chains generate significant internal frictional heat due to their inherent viscoelastic properties. Existing hydrogenated nitrile butadiene rubber crosslinked network structures not only lack efficient heat conduction pathways, leading to heat accumulation within the matrix, but also, under long-term high-temperature heat accumulation, the polymer backbone is prone to oxidative breakage or excessive crosslinking and hardening, causing the rubber composition to lose elasticity and become brittle. Relying solely on the heat resistance of the matrix resin itself is insufficient to meet the anti-aging requirements under extreme working conditions.

[0004] Secondly, there is the issue of interfacial compatibility between the non-polar reinforcing phase and the polar rubber matrix. To impart high modulus properties to the rubber composition, it is usually necessary to introduce a rigid phase such as high-modulus aramid fibers into the soft segment rubber matrix. However, aramid fibers are highly crystalline and have a chemically inert surface, lacking reactive functional groups with the polar hydrogenated nitrile butadiene rubber polymer chains, making it difficult to form a molecular-level blended cross-linked network. This "two-phase separation" microstructure means that during dynamic flexural bending, stress cannot be effectively transferred between the soft and hard phases, and stress concentration easily occurs at the interface due to modulus mismatch, becoming the source of crack initiation.

[0005] Therefore, how to regulate the molecular structure of hydrogenated nitrile butadiene rubber matrix through chemical modification, construct a multiphase cross-linked network with chemically bonded interfaces, and build an efficient heat conduction pathway within the rubber polymer system is a key technical challenge that urgently needs to be solved in the field of polymer materials. To this end, a rubber composite material for transmission belts and its preparation method are proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a rubber composite material for transmission belts and a method for preparing the same.

[0007] To achieve the above objectives, the present invention provides the following technical solution: Unless otherwise specified, all parts in this invention are parts by weight.

[0008] This invention provides a method for preparing a rubber composite material for transmission belts. The method is as follows: Start an internal mixer, set the temperature to 60°C and the rotation speed to 60 rpm, add 100 parts of hydrogenated nitrile butadiene rubber (Zetpol 2010) and masticate for 1 minute; add rubber compounding agents and a protective system, increase the rotation speed to 80 rpm, and mix for 2 minutes; add 10-20 parts of modified aramid pulp and 25-40 parts of hybrid masterbatch, and continue mixing for 3 minutes, at which point high shear force is used to disperse the fibers; add 35 parts of reinforcing agent and mix for 3 minutes; when the discharge temperature reaches 140°C, discharge the rubber to obtain a compound; perform a two-stage mixing process on the compound and then vulcanize it (vulcanizing at 170°C and 15 MPa pressure) to obtain the rubber composite material. Modified aramid pulp was prepared from aramid pulp, dopamine hydrochloride, and a silane coupling agent; The hybrid masterbatch was prepared from graphene oxide, hexagonal boron nitride, 1-butyl-3-methylimidazolium hexafluorophosphate, and carboxyl-terminated liquid nitrile rubber.

[0009] The preferred method for preparing modified aramid pulp is as follows: 50 parts of aramid pulp (Kevlar 1F538) are added to 1000 parts of Tris-HCl buffer solution (pH=8.5, concentration 10mM), ultrasonically dispersed for 30 min, 8-12 parts of dopamine hydrochloride are added, and the mixture is stirred and reacted at 25℃ for 15-20 h; the mixture is filtered and washed 3 times with deionized water, and dried in a vacuum oven at 60℃ for 10 h to obtain dopamine-coated aramid; 6 parts of silane coupling agent KH-570 are added to 1000 parts of ethanol aqueous solution (ethanol to water volume ratio 9:1), the pH is adjusted to 4.0 with acetic acid, and hydrolyzed for 30 min; dopamine-coated aramid is added, ultrasonically dispersed at 50℃ for 30 min, and then stirred and reacted for 4 h; the mixture is filtered, washed with ethanol, and vacuum dried at 80℃ for 12 h to obtain modified aramid pulp.

[0010] The preferred method for preparing the hybrid masterbatch is as follows: 30 parts of graphene oxide (monolayer ratio >90%, sheet thickness 0.8-1.2 nm, sheet size 0.5-5 μm, oxygen content approximately 40%) and 70 parts of hexagonal boron nitride (average particle size D50 of 200 nm, specific surface area of ​​30 m²) are mixed. 2Mix (g) and add to 600 parts of ethanol solution containing 5-10 parts of 1-butyl-3-methylimidazolium hexafluorophosphate. Sonicate at 60°C for 2 hours to form a suspension. Dissolve 200 parts of terminal carboxyl liquid nitrile rubber (PB92666, Guangdong Wengjiang Chemical Reagent Co., Ltd.) in 600 parts of acetone to obtain a rubber solution. Add the suspension to the rubber solution and mix evenly. Place the mixture in a rotary evaporator and concentrate it to a viscous state. Then place it in a vacuum oven to dry and obtain a pre-dispersed rubber compound. Grind the pre-dispersed rubber compound 5 times on a three-roll mill with the roller gap adjusted to 0.5 mm to obtain a hybrid masterbatch.

[0011] Preferably, the rubber compounding agent consists of 20-28 parts of active crosslinking agent and 6 parts of processing aid; the protective system is obtained by mixing 2.0 parts of antioxidant 445 and 1.2 parts of antioxidant MB.

[0012] Preferably, the active crosslinking agent is zinc methacrylate; the reinforcing agent is carbon black; and the processing aid consists of 1 part stearic acid and 5 parts zinc oxide.

[0013] Preferably, the two-stage mixing process is as follows: After cooling the mixed rubber to room temperature, it is put into an open mill, the roller temperature is adjusted to 45°C, the vulcanization system is added, and it is passed through 5 times (roller gap 0.5mm) and formed into triangular bundles 3 times to ensure that the vulcanizing agent is evenly dispersed and does not damage the fiber length; the sheet is then cut and left to stand for more than 8 hours before use.

[0014] Preferably, the vulcanization system consists of 4-6 parts dicumyl peroxide and 3.0-4.5 parts triallyl isocyanurate.

[0015] Another aspect of the present invention provides a rubber composite material for transmission belts, wherein the rubber composite material is prepared by any of the above preparation methods; the raw materials for preparing the rubber composite material include hydrogenated nitrile rubber, active crosslinking agent, processing aid, protective system, modified aramid pulp, thermally conductive hybrid masterbatch, carbon black, and vulcanization system.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention significantly solves the problem of poor interfacial bonding between inert aramid fibers and polar hydrogenated nitrile rubber matrix by utilizing the biomimetic adhesion of polydopamine and the chemical bridging of silane coupling agents. The polydopamine layer, with its catechol and amino functional groups, forms a strong active coating on the aramid surface, providing sites for subsequent reactions. The introduced sulfur-containing silane coupling agent binds to the polydopamine layer at one end via hydrogen bonds or covalent bonds, while the sulfur element at the other end directly participates in the vulcanization and crosslinking reaction of the rubber. This chemically bonded "fiber-intermediate-rubber" structure transforms the original physical-mechanical interlocking into chemical anchoring, effectively transferring stress during dynamic flexural processes, inhibiting the initiation and propagation of interfacial microcracks, and fundamentally preventing fiber pull-out.

[0017] 2. This invention constructs a highly efficient heat conduction network, effectively solving the problem of core heat accumulation in rubber materials due to poor thermal conductivity. Graphene oxide possesses excellent in-plane thermal conductivity, while boron nitride exhibits good insulating and thermally conductive properties. The hybrid use of these two materials forms a complementary heat conduction network. The introduced imidazole ionic liquid utilizes the π-π conjugation and electrostatic repulsion between its cations and the graphene oxide surface to overcome the problem of easy agglomeration of nanofillers in the polymer matrix. This modification allows the filler to be uniformly dispersed in a peeled state within the rubber matrix, significantly reducing interfacial thermal resistance. When the transmission belt generates a large amount of hysteretic heat during high-speed operation, this hybrid network can quickly conduct internal heat to the surface for dissipation, preventing thermo-oxidative aging or chain breakage of the rubber macromolecular chains due to localized high temperatures, and significantly improving the material's thermal fatigue life.

[0018] 3. This invention utilizes the metallic ionic properties and in-situ polymerization capability of zinc methacrylate to construct a third-phase interface layer between the reinforcing material and the matrix. During the compounding process, zinc methacrylate not only participates in peroxide vulcanization as a co-crosslinking agent, increasing the crosslinking density, but its polar metal centers can also undergo physical adsorption and coordination with the polar groups on the modified aramid surface. This interfacial self-assembly effect forms a large number of ionic crosslinking points in the rubber matrix. This mechanism significantly improves the dynamic storage modulus of the composite material without significantly increasing hysteresis loss like traditional carbon black reinforcement, thus reducing dynamic heat generation at the source while ensuring high rigidity and transmission efficiency of the transmission belt.

[0019] 4. The liquid-phase pre-dispersion process used in this invention overcomes the technical bottleneck of difficulty in dispersing nano-thermal conductive fillers through direct dry mixing. Due to their large specific surface area, nanomaterials are prone to severe agglomeration during traditional open mill or internal mixer dry mixing, forming stress concentration points and consequently reducing material performance. This invention pre-disperses the filler in a low-viscosity solvent and liquid rubber, utilizing the wetting effect of the liquid medium to open the filler agglomerates and fix them within the liquid rubber molecular chains. Subsequently, this masterbatch is blended with a solid hydrogenated nitrile butadiene rubber matrix, effectively "diluting" the high-concentration dispersion into the matrix. This process ensures the continuity and uniformity of the thermally conductive network in the macroscopic rubber compound, maximizing the functionality of the nano-filler.

[0020] 5. The specific segmented temperature-controlled intensive mixing process designed in this invention precisely regulates the mixing state and reaction process of each component, achieving an optimal balance between processing performance and physical properties. In the low-temperature, low-speed section, the high viscosity and high shear force of the rubber compound are used to forcibly open the fiber bundles, allowing them to achieve monofilament-level dispersion in the matrix. Subsequently, the rotation speed is increased to induce a preliminary grafting reaction between zinc methacrylate and the matrix and fillers. The discharge temperature is strictly controlled to prevent premature decomposition of the peroxide crosslinking system. This precise control of the process window ensures that the integrity of the fiber length is not damaged by excessive shearing and also ensures the effective conversion of active additives, resulting in a compound with excellent rheological processability. Attached Figure Description

[0021] Figure 1 The figures show the flexural fatigue performance test results of Examples 1-4 and Comparative Examples 1-2, 6, and 8 of the present invention. Detailed Implementation

[0022] 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.

[0023] Please see Figure 1 This invention provides a rubber composite material for transmission belts and a method for preparing the same. The technical solution is as follows: Example 1 50 parts of aramid pulp were added to 1000 parts of Tris-HCl buffer solution (pH=8.5, concentration 10mM), ultrasonically dispersed for 30 min, and 8 parts of dopamine hydrochloride were added. The mixture was stirred at 400 rpm for 15 h at 25 °C. The mixture was filtered and washed three times with deionized water, and then dried in a vacuum oven at 60 °C for 10 h to obtain dopamine-coated aramid. 6 parts of silane coupling agent KH-570 were added to 1000 parts of an ethanol-water solution (ethanol to water volume ratio 9:1), the pH was adjusted to 4.0 with acetic acid, and the mixture was stirred at 200 rpm for 30 min to hydrolyze. Dopamine was added to coat the aramid, and the mixture was ultrasonically dispersed at 50 °C for 30 min, followed by stirring at 300 rpm for 4 h. After filtration, the mixture was washed with ethanol and vacuum dried at 80 °C for 12 h to obtain modified aramid pulp.

[0024] 30 parts of graphene oxide and 70 parts of hexagonal boron nitride were mixed and added to a 600-part ethanol solution containing 5 parts of 1-butyl-3-methylimidazolium hexafluorophosphate. The mixture was ultrasonically vibrated at 60°C for 2 hours to form a suspension. 200 parts of terminal carboxyl liquid nitrile rubber were dissolved in 600 parts of acetone to obtain a rubber solution. The suspension was added to the rubber solution and mixed evenly. The solution was then placed in a rotary evaporator and concentrated to a viscous state. After that, it was dried in a vacuum oven to obtain a pre-dispersed rubber compound. The pre-dispersed rubber compound was then ground 5 times on a three-roll mill with a roller gap of 0.5 mm and a speed ratio of 1:3:9 to obtain a hybrid masterbatch.

[0025] Start the internal mixer, set the temperature to 60℃ and the speed to 60 rpm, add 100 parts of hydrogenated nitrile rubber and mix for 1 minute; add 20 parts of active crosslinking agent zinc methacrylate, 6 parts of processing aids and a protective system, increase the speed to 80 rpm and mix for 2 minutes; add 10 parts of modified aramid pulp and 25 parts of hybrid masterbatch, and continue mixing for 3 minutes; add 35 parts of reinforcing agent carbon black and mix for 3 minutes. When the discharge temperature reaches 140℃, discharge the rubber to obtain the compound; cool the compound to... After reaching room temperature, the mixture is fed into an open mill, the roll temperature is adjusted to 45℃, the vulcanization system is added, and the mixture is passed through a thin mill 5 times (roll gap 0.5mm) and formed into triangular sheets 3 times. The sheets are then sheeted and left to stand for more than 8 hours before use. The mixture is then vulcanized at 170℃ and 15MPa pressure to obtain a rubber composite material. The protective system is a mixture of 2.0 parts of antioxidant 445 and 1.2 parts of antioxidant MB. The processing aid consists of 1 part of stearic acid and 5 parts of zinc oxide. The vulcanization system consists of 4 parts of dicumyl peroxide and 3.0 parts of triallyl isocyanurate.

[0026] Example 2 Referring to the preparation method and parameters of Example 1, the difference is that when preparing the modified aramid pulp, 9 parts of dopamine hydrochloride were added and the mixture was stirred and reacted at 25°C for 16 hours; when preparing the hybrid masterbatch, 6.5 parts of 1-butyl-3-methylimidazolium hexafluorophosphate were used; 22 parts of zinc methacrylate were used; 12 parts of the modified aramid pulp were used; and 30 parts of the hybrid masterbatch were used; the vulcanization system consisted of 4.5 parts of dicumyl peroxide and 3.5 parts of triallyl isocyanurate.

[0027] Example 3 Referring to the preparation method and parameters of Example 1, the difference is that when preparing modified aramid pulp, 10.5 parts of dopamine hydrochloride were added and the mixture was stirred and reacted at 25°C for 18 hours; when preparing hybrid masterbatch, 8 parts of 1-butyl-3-methylimidazolium hexafluorophosphate were used; 25 parts of zinc methacrylate were used; 16 parts of modified aramid pulp were used; and 35 parts of hybrid masterbatch were used; the vulcanization system consisted of 5 parts of dicumyl peroxide and 4.0 parts of triallyl isocyanurate.

[0028] Example 4 The preparation method and parameters of Example 1 are the same, except that when preparing the modified aramid pulp, 12 parts of dopamine hydrochloride are added and the mixture is stirred and reacted at 25°C for 20 hours; when preparing the hybrid masterbatch, 10 parts of 1-butyl-3-methylimidazolium hexafluorophosphate are used; 28 parts of zinc methacrylate are used; 20 parts of modified aramid pulp are used; and 40 parts of hybrid masterbatch are used; the vulcanization system consists of 6 parts of dicumyl peroxide and 4.5 parts of triallyl isocyanurate.

[0029] Comparative Example 1 The preparation method and parameters of Example 1 were used, except that the aramid pulp was not modified.

[0030] Comparative Example 2 The preparation method and parameters of Example 1 are the same, except that the hybrid masterbatch is not used, and graphene oxide, hexagonal boron nitride and carboxyl-terminated liquid nitrile rubber are directly added to the internal mixer.

[0031] Comparative Example 3 The preparation method and parameters are the same as in Example 1, except that graphene oxide is not added to the hybrid masterbatch.

[0032] Comparative Example 4 The preparation method and parameters of Example 1 are the same, except that hexagonal boron nitride is not added to the hybrid masterbatch.

[0033] Comparative Example 5 The preparation method and parameters of Example 1 are the same, except that ordinary liquid nitrile rubber (Nipol1312) is used instead of carboxyl-terminated liquid nitrile rubber.

[0034] Comparative Example 6 The preparation method and parameters were the same as in Example 1, except that zinc methacrylate was not added.

[0035] Comparative Example 7 The preparation method and parameters of Example 1 are the same, except that the vulcanization system is replaced with 0.5 parts sulfur, 1.5 parts accelerator CZ and 0.1 parts dicumyl peroxide.

[0036] Comparative Example 8 Referring to the preparation method and parameters of Example 1, the difference is that the segmented temperature change is cancelled, the internal mixer is started, the temperature is directly set to 110°C, the speed is set to a constant 80 rpm, and hydrogenated nitrile rubber, zinc methacrylate, processing aids, protective system, modified aramid pulp, hybrid masterbatch and reinforcing agent are added in sequence.

[0037] Experimental Example 1: Heat Aging Resistance Test According to GB / T 3512-2014, the heat resistance aging performance was tested under hot air aging conditions of 150℃×72h; the tensile strength was tested according to the standard of GB / T528-2009, and the sample shape was dumbbell-shaped. The thermal conductivity of the materials in the examples and comparative examples was tested using a DXF-500 thermal conductivity meter. The results are shown in Table 1.

[0038] Table 1. Heat aging resistance test results of Examples 1-4, Comparative Examples 2-4, and Comparative Example 7 Experimental Example 2: Adhesion Strength Test The H-type pull-out force was tested according to the standard GB / T 2942-2009; an H-type sample embedded with aramid fiber was prepared, with a rubber strip width of 6.5 mm and a thickness of 3.2 mm, and the maximum force required to pull the fiber out of the rubber matrix was tested; the results are shown in Table 2.

[0039] Table 2 Adhesion strength tests of Examples 1-4 and Comparative Examples 1-2 and 5-6 Experiment Example 3: Flexural Fatigue Performance Test The test was conducted according to GB / T 13934-2006 "Determination of Flexural Cracking and Crack Growth of Vulcanized Rubber or Thermoplastic Rubber (Demercia Method)"; the number of flexural cycles (in ten thousand) at which a Grade 1 crack was produced was recorded; the results are shown in Table 3.

[0040] Table 3. Flexural fatigue performance tests of Examples 1-4 and Comparative Examples 1-2, 6, and 8 As shown in Tables 1-3, unlike conventional physical filling, this application utilizes dopamine / silane bilayer modified aramid and carboxyl-terminated liquid rubber carrier to establish a robust chemical bridge between inert fibers, nanofillers, and hydrogenated nitrile rubber matrix in Examples 1-4. The in-situ polymerization of zinc methacrylate acts like "rivets" interwoven within the interface layer, preventing interfacial delamination even after hundreds of thousands of flexural cycles, significantly improving dynamic fatigue life. Furthermore, this application avoids the stacking of two-dimensional materials through liquid-phase methods, achieving monofilament-level dispersion of aramid using low-temperature, high-shear force, and precisely controlling the discharge temperature to balance zinc methacrylate grafting and scorch prevention. This fusion of formulation and process enhances the material's heat aging resistance and dynamic mechanical properties.

[0041] In Comparative Example 1, the aramid pulp was not modified. Due to the lack of active functional groups on the surface of the inert aramid, it could not form chemical bonds with the rubber matrix, resulting in a vicious cycle of "debonding-friction-heat generation" under dynamic stress, which quickly led to cracking. In Comparative Example 2, without using a hybrid masterbatch, graphene oxide, hexagonal boron nitride, and carboxyl-terminated liquid nitrile rubber were directly added to the internal mixer. The nanofillers agglomerated severely during dry mixing, failing to form an effective heat conduction network. At the same time, the agglomerated large particles of filler disrupted the continuity of the rubber matrix, becoming defects inside the material and deteriorating its mechanical strength and flexural strength. In Comparative Example 3, no graphene oxide was added to the hybrid masterbatch, relying solely on hexagonal boron nitride for thermal conductivity. Although boron nitride is the primary heat transfer carrier, the lack of graphene oxide as a flexible "bridging" agent with a large aspect ratio makes it difficult to form tight phonon transport contact points between the rigid boron nitride sheets, leading to increased contact thermal resistance. Furthermore, the absence of graphene oxide weakens the physical reinforcement effect of the nanofiller on the rubber matrix. In Comparative Example 4, the absence of hexagonal boron nitride resulted in the lack of a major high-thermal-conductivity transport channel. A small amount of graphene oxide alone was insufficient to construct a long-range, effective volumetric thermal conductivity network within the rubber matrix, demonstrating that hexagonal boron nitride plays a crucial and indispensable role in the construction of the thermal conductivity network in this application. In Comparative Example 5, the use of carboxyl-free liquid rubber weakened the wettability and bonding force between the filler and the rubber matrix, leading to a double decrease in H-pulling force and thermal conductivity, and an increase in interfacial thermal resistance. In Comparative Example 6, the absence of zinc methacrylate resulted in the lack of in-situ polymerized metal ion crosslinking enhancement, leading to insufficient overall modulus of the material and the loss of the auxiliary adhesive effect of zinc methacrylate on the fiber interface. In Comparative Example 7, the vulcanization system was replaced with 0.5 parts sulfur, 1.5 parts accelerator CZ, and 0.1 parts dicumyl peroxide. The low bond energy of the sulfur bonds caused them to break rapidly at high temperatures, significantly reducing the strength retention rate and failing to meet the high-temperature operating conditions of the transmission belt. In Comparative Example 8, the segmented temperature variation was eliminated. Under high-temperature initial conditions, the matrix viscosity of the hydrogenated nitrile rubber decreased rapidly, resulting in insufficient shear force applied to the aramid pulp during mixing. This failed to forcibly open the highly entangled fiber bundles into a monofilament state, causing the fibers to aggregate in bundles at the microscopic level. This not only failed to provide reinforcement but also became a significant source of stress concentration defects.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a rubber composite material for transmission belts, characterized in that: The preparation method is as follows: hydrogenated nitrile butadiene rubber is added to a mixer for plasticizing; rubber compounding agents and a protective system are added, and the speed is increased for mixing; modified aramid pulp and hybrid masterbatch are added for further mixing; the rubber compound is obtained by discharge. The rubber compound is subjected to two-stage mixing and then vulcanized to obtain the rubber composite material. The modified aramid pulp was prepared from aramid pulp, dopamine hydrochloride, and a silane coupling agent. The hybrid masterbatch is prepared from graphene oxide, hexagonal boron nitride, 1-butyl-3-methylimidazolium hexafluorophosphate, and carboxyl-terminated liquid nitrile rubber.

2. The method for preparing a rubber composite material for a transmission belt according to claim 1, characterized in that: The modified aramid pulp is prepared as follows: the aramid pulp is dispersed in a Tris-HCl buffer solution, and dopamine hydrochloride is added and stirred to react; the mixture is filtered and washed with deionized water, and then vacuum dried to obtain dopamine-coated aramid; silane coupling agent KH-570 is added to an ethanol aqueous solution, the pH is adjusted with acetic acid, and the mixture is hydrolyzed; the dopamine-coated aramid is added and ultrasonically dispersed, stirred to react, and then filtered, washed, and vacuum dried to obtain the modified aramid pulp.

3. The method for preparing a rubber composite material for a transmission belt according to claim 1, characterized in that: The hybrid masterbatch is prepared as follows: graphene oxide and hexagonal boron nitride are mixed and added to ethanol containing 1-butyl-3-methylimidazolium hexafluorophosphate, and ultrasonically vibrated to form a suspension; the carboxyl-terminated liquid nitrile rubber is dissolved in acetone to obtain a rubber solution; the suspension is added to the rubber solution and mixed evenly, and then placed in a rotary evaporator to remove the solvent under vacuum to obtain a pre-dispersed rubber compound; the pre-dispersed rubber compound is ground on a three-roll mill to obtain the hybrid masterbatch.

4. The method for preparing a rubber composite material for a transmission belt according to claim 1, characterized in that: The rubber compounding agent is composed of an active crosslinking agent and a processing aid; the protective system is obtained by mixing antioxidant 445 and antioxidant MB.

5. The method for preparing a rubber composite material for a transmission belt according to claim 4, characterized in that: The active crosslinking aid is zinc methacrylate; the processing aid is composed of stearic acid and zinc oxide.

6. The method for preparing a rubber composite material for a transmission belt according to claim 1, characterized in that: The two-stage mixing process is as follows: after cooling the mixed rubber to room temperature, it is fed into a two-roll mill, a vulcanization system is added, and the mixture is passed through a thin mill; the sheets are then ready for use.

7. The method for preparing a rubber composite material for a transmission belt according to claim 6, characterized in that: The vulcanization system consists of dicumyl peroxide and triallyl isocyanurate.

8. A rubber composite material for transmission belts, characterized in that: The rubber composite material is prepared by any one of the preparation methods described in claims 1-7; the raw materials for preparing the rubber composite material include hydrogenated nitrile rubber, rubber compounding agents, a protective system, modified aramid pulp, thermally conductive hybrid masterbatch, and a vulcanization system.

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