Rubber composition with high thermal conductivity and heat dissipation and preparation method thereof

Abstract

The invention relates to the technical field of rubber products, and particularly discloses a rubber composition with high thermal conductivity and heat dissipation and a preparation method thereof. The rubber composition with high thermal conductivity and heat dissipation is prepared from the following raw materials in parts by weight: 120 to 125 parts of rubber base material, 35 to 45 parts of carbon black, 1 to 3 parts of thermal superconducting filler, 1 to 2 parts of sulfur, 3 to 4 parts of accelerant, 4 to 7 parts of activating agent and 3 to 4 parts of anti-aging agent, the thermal superconducting filler comprises a graphene modified filler and aluminum oxide whiskers. The rubber composition with high heat conduction and heat dissipation can be used for military vehicles, has excellent heat conduction and heat dissipation performance, can quickly export heat generated by rubber products, effectively improves the concealment of the military vehicles in complex environments such as forests, deserts and snowfields, is not easily detected by infrared rays, helps the vehicles to better merge into the natural environment, and has good application prospects. And the concealment and the survivability of military actions are enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rubber products, more particularly, it relates to a high-thermal-conductivity and high-heat-dissipation rubber composition and a preparation method thereof. BACKGROUND

[0002] The camouflage tire is generally used for military vehicles, and the surface thereof is provided with a camouflage pattern adapted to the environment, which can effectively improve the visual concealment of the vehicle in complex environments such as forests, deserts and snow-covered areas, help the vehicle to better integrate into the natural environment, and thus enhance the concealment and survivability of military operations.

[0003] However, in the long-term high-speed driving or high-intensity tasks of the existing camouflage tire, a large amount of heat is easily generated due to the continuous friction with the ground and the influence of high temperature environment, which causes the internal temperature of the tire to rise sharply. On the one hand, high temperature can cause molecular structure aging, resulting in hardening or softening of the rubber material, reducing the grip and handling stability of the tire, affecting the driving safety, and on the other hand, it can increase the internal pressure and cause tire burst due to abnormal increase of tire pressure. In addition, as one of the heat sources of the vehicle, local overheating of the tire can form a clear heat source signal, which can significantly enhance the infrared radiation characteristics and be easily discovered by the enemy's infrared detection technology, thereby exposing the vehicle position and losing the concealment advantage. It is necessary to reduce the temperature in a short time to avoid infrared detection.

[0004] With regard to the above-mentioned related technology, the inventors found that the conventional tire heat dissipation method mainly depends on the thermal conductivity of the raw rubber material itself, the addition of thermal conductive fillers, or the tire structure design, such as the tread pattern, internal air cavity, etc. However, the thermal conductive fillers in the existing rubber often have the problem of insufficient compatibility, which can easily cause filler aggregation and pigment peeling, thereby sacrificing the mechanical properties of the rubber product. The method of tire structure design has limited heat dissipation efficiency, which is difficult to meet the rapid heat dissipation requirements of military vehicles in extreme environments, especially in the state of high load and high speed driving. The heat dissipation capacity of the existing camouflage tire is particularly insufficient. SUMMARY

[0005] In order to enhance the heat dissipation capacity of the tire and improve the mechanical properties and concealment performance of the tire, the present application provides a high-thermal-conductivity and high-heat-dissipation rubber composition and a preparation method thereof.

[0006] In the first aspect, the present application provides a high-thermal-conductivity and high-heat-dissipation rubber composition, which adopts the following technical scheme: a high-thermal-conductivity and high-heat-dissipation rubber composition, according to weight parts, the raw materials include 120-125 parts of rubber base material, 35-45 parts of carbon black, 1-3 parts of thermal superconducting filler, 1-2 parts of sulfur, 3-4 parts of accelerator, 4-7 parts of activator and 3-4 parts of antioxidant. The thermal superconducting filler includes a graphene modified filler and an aluminum oxide whisker.

[0007] By adopting the technical scheme, the application uses the non-metallic component and the metallic component as the thermal superconducting filler, wherein the graphene modified filler is a graphene modified filler with an oxide graphene flake as a substrate and a boron nitride nanosheet vertically grown on the surface of the substrate to form a hetero-layer structure. The oxide graphene has excellent in-plane thermal conductivity and can form a fast thermal conduction channel in a two-dimensional plane. The vertically grown boron nitride nanosheet forms a hetero three-dimensional structure, which can efficiently conduct heat from the rubber matrix and conduct to the oxide graphene for further conduction, and can vertically conduct heat in the oxide graphene to other fillers and interfaces, thereby realizing an isotropic high-efficiency three-dimensional thermal conduction network and significantly improving the thermal conduction and heat dissipation efficiency, which cannot be realized by simple physical mixing.

[0008] In addition, the graphene modified filler with the hetero three-dimensional structure can effectively prevent self-aggregation between the boron nitride and effectively overcome the stacking between the oxide graphene layers, and is more uniformly dispersed. In the rubber matrix, the graphene modified filler with the hetero three-dimensional structure is embedded in the rubber matrix and forms a stronger and more stable binding force with the rubber matrix. When the rubber product is subjected to an external force, the hetero structure can effectively transmit stress from the soft rubber matrix to the modified filler with high modulus, thereby increasing the toughness and strength of the rubber product and effectively solving the technical problem of mechanical property degradation caused by the addition of the thermal conductive filler.

[0009] Further, the one-dimensional linear aluminum oxide whisker plays a role of a longitudinal bridge and a bond between the graphene modified fillers with the hetero structure, and cooperatively builds a more complete, continuous and efficient thermal conduction network, thereby greatly improving the thermal conduction efficiency of the thermal conduction path. The prepared rubber product can meet the rapid heat dissipation requirement of the military vehicle under extreme environment, especially under the condition of high load and high speed.

[0010] Optionally, the raw material of the rubber matrix includes a natural rubber wet rubber and a low-heat-generation modified natural rubber.

[0011] By adopting the technical scheme, the natural rubber wet rubber provides good wear resistance and chemical resistance; and the low-heat-generation modified natural rubber changes the molecular structure through chemical modification, reduces internal friction heat generation, effectively reduces heat generation during tire operation, alleviates the negative effects of high temperature, and delays the aging process of the rubber.

[0012] Optionally, the mass ratio between the graphene modified filler and the aluminum oxide whisker is (1.5-2.5):1.

[0013] Optionally, the preparation method of the graphene modified filler includes the following steps: dispersing the oxide graphene in water to form a suspension through ultrasonic treatment; The organic solvent, the boron source and the nitrogen source are added to the suspension, and after stirring to form a homogeneous system, the reaction is carried out at 180-220 DEG C to generate boron nitride nanosheets on the surface of graphene oxide in situ, and then cooled to 70-80 DEG C, and the compatible modifier is added dropwise, and after constant temperature stirring reaction, centrifugation, washing and drying, the graphene modified filler coated with boron nitride nanosheets is obtained.

[0014] By adopting the above technical scheme, the inventors vertically deposit boron nitride nanosheets on the surface of graphene oxide by in-situ growth through the method of liquid deposition, and then directly add a compatible modifier in the reaction system for compatibility modification, without separation. The compatible modifier molecules can directly react with the hydroxyl groups and other groups on the surface of the boron nitride in the liquid phase. The boron nitride growth and composite filler modification can be realized by one-step method to obtain graphene modified filler, which has better dispersibility and lower interfacial thermal resistance. The compatibility and interfacial bonding force between the rubber matrix are significantly improved. Moreover, the process flow is simple and suitable for large-scale production.

[0015] Optionally, the mass ratio between the boron nitride nanosheets and the graphene oxide is 1:(0.5-1.5).

[0016] By adopting the above technical scheme, the inventors found that when the graphene modified filler is too little, the thermal conductivity and mechanical properties of the rubber product are both decreased. This may be because the boron nitride nanosheets cannot completely cover the surface of the graphene oxide, and the exposed graphene oxide layers are prone to stacking and agglomeration due to strong van der Waals force, resulting in the fracture of the thermal conduction network. In addition, the high electrical conductivity of graphene oxide may cause local charge accumulation in the rubber matrix, which may further interfere with the heat dissipation path under certain high-frequency working conditions.

[0017] When the graphene modified filler is too much, the thermal conductivity and mechanical properties of the rubber product are both decreased. This may be because the excess boron nitride nanosheets form a thick layer of coating on the surface of the graphene oxide layers, or even form independent boron nitride agglomerates, resulting in rapid increase of the interfacial thermal resistance and inability to form a strong anchor with the rubber matrix, thus leading to a decrease in mechanical properties.

[0018] Optionally, the compatible modifier is mercaptopropyl triethoxysilane.

[0019] By adopting the above technical scheme, mercaptopropyl triethoxysilane is selected as the compatible modifier. The silicon alcohol group at one end can hydrolyze and condense with the hydroxyl groups on the surface of the graphene-boron nitride composite filler and the edge sites of boron nitride, forming a stable chemical bond structure to coat the filler. The heterostructure advantageously significantly improves the compatibility between the non-metallic filler and the rubber matrix. The mercapto group at the other end faces outward, and a small part of the mercapto groups can coordinate and combine with the alumina whiskers, promoting the connection stability between the non-metallic components and the metallic components.

[0020] Further, most of the mercapto groups can directly react with the double bonds of the rubber during vulcanization, providing additional, strong covalent bonds and points, further enhancing the interfacial bonding force between the graphene modified filler and the rubber matrix.

[0021] Optionally, the alumina whisker is a modified alumina whisker with polybutadiene grafted on the surface.

[0022] Optionally, the preparation method of the modified alumina whisker comprises the following steps: The alumina whisker is added to a 3-5wt% triethylamine solution, and after stirring and reaction, centrifugation, washing and drying, a modified alumina whisker intermediate is obtained. The modified alumina whisker intermediate is added to a 10-15wt% hydroxyl-terminated polybutadiene solution, and after stirring and reaction under nitrogen protection, centrifugation, washing and drying, the modified alumina whisker is obtained.

[0023] By using the above technical solution, by grafting HTPB on the surface of alumina, flexible long molecular chains are introduced on the surface of the alumina whisker, which can effectively wrap and wrap the one-dimensional alumina whisker, reduce the agglomeration between the alumina whiskers, ensure the dispersion stability of the alumina whiskers in the rubber matrix, and further improve the compatibility of the polybutadiene structure with the rubber matrix, realize the flexible filtering from the surface of the rigid filler to the flexible rubber matrix, greatly reduce the stress concentration, and improve the toughness and mechanical properties of the rubber product.

[0024] In the present application, TEA is used as a bonding agent, and the adsorption energy of TEA on the surface of alumina whisker is significantly higher than that of HTPB on the surface of alumina whisker. A bridge between alumina whisker and HTPB is formed by forming a coordination bond / hydrogen bond between the amino group and the hydroxyl group on the surface of the alumina whisker. Due to the high similarity in structure and polarity between the alkyl chain in TEA and the polybutadiene backbone of HTPB, the compatibility is excellent, and during the subsequent mixing process, the long molecular chains of HTPB can strongly physically entangle and interpenetrate with the alkyl chains of TEA, thereby realizing the fixation of HTPB on the surface of the alumina whisker. In addition, the remaining hydroxyl groups in the TEA molecule can also combine with the terminal hydroxyl groups of HTPB, further strengthening the interfacial bonding and maintaining stable performance at high temperatures.

[0025] By using the amphiphilic structure of TEA molecules, an organic monolayer is constructed on the inorganic surface by strong chemical adsorption, and then by using the excellent compatibility and intermolecular forces between the organic layer and the HTPB polymer, efficient and stable grafting is realized. Compared with the traditional process of forming a covalent bond grafting after forming a chemical bond using silane coupling agent, the process is simpler, more efficient and easier to implement.

[0026] In a second aspect, the present application provides a preparation method of a high-thermal-conductivity and high-heat-dissipation rubber composition, which adopts the following technical solution: A method for preparing a rubber composition with high thermal conductivity and heat dissipation includes the following steps: Weigh the raw materials according to the weight proportions, mix the rubber base material, carbon black, thermal superconducting filler, activator and antioxidant at 140-150℃, then add accelerator and sulfur to form a rubber compound, and vulcanize the rubber compound at 150-160℃ after standing.

[0027] By adopting the above technical solution, high-temperature mixing is first carried out. The thermal superconducting filler constructs a uniform three-dimensional thermally conductive network in the rubber substrate, which effectively avoids agglomeration and interface weakening caused by filler addition. The interface bonding force is better, and the filler of this application will not poison the high-temperature vulcanization process, ensuring the stability of the vulcanization process and making it suitable for large-scale production.

[0028] In summary, this application has the following beneficial effects: 1. Since this application uses a mixture of graphene-modified filler with a heterogeneous structure and alumina whiskers with a one-dimensional linear structure as a thermal superconducting filler, the alumina whiskers play the role of a longitudinal bridge and link in the graphene-modified filler, and synergistically construct a complete, continuous and efficient three-dimensional thermal conductive network structure, which greatly improves the thermal conductivity. The prepared rubber products can meet the rapid heat dissipation requirements of military vehicles in extreme environments, especially the heat dissipation requirements under high load and high speed driving conditions.

[0029] 2. In this application, boron nitride nanosheets are vertically deposited on the surface of graphene oxide through in-situ growth using liquid phase deposition. Then, mercaptopropyltriethoxy groups are added to the reaction system in one step for compatibility modification. The resulting heterogeneous three-dimensional graphene-modified filler can effectively prevent the self-aggregation effect between boron nitrides and effectively overcome the stacking between graphene oxide sheets, resulting in more uniform dispersion, good compatibility with the rubber matrix, and ensuring excellent mechanical properties of the rubber products.

[0030] 3. This application utilizes the amphiphilic structure of triethylamine to construct an organic monolayer on the surface of alumina whiskers through strong chemical adsorption as a bridge. By leveraging the excellent compatibility and intermolecular forces between this organic layer and hydroxyl-terminated polybutadiene, efficient and stable grafting is achieved. This introduces a long molecular chain structure onto the surface of the alumina whiskers, effectively reducing the aggregation between alumina whiskers. Its polybutadiene structure is compatible with the rubber matrix, realizing flexible filtration from the rigid filler surface to the flexible rubber matrix, greatly reducing stress concentration, and improving the toughness and mechanical properties of rubber products. Detailed Implementation

[0031] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0032] raw material The raw materials used in the examples and comparative examples in the present application are commercially available products, specifically: Natural rubber wet rubber, selected from Qingdao Jin Ruina Rubber Technology Co., Ltd., with a brand of T-145, the raw material contains natural rubber latex and modified white carbon black SiO2, the specific preparation method refers to the preparation method of wet rubber disclosed in the wet mixing rubber of the invention patent 201810058058X embodiment 4; Low heat build-up modified natural rubber, selected from Qingdao Jin Ruina Rubber Technology Co., Ltd., with a brand of NRX-X1, is a natural rubber full latex produced by using biological agents and modifiers. The isophthalic dihydrazide is used as a modifier to react with the aldehyde group at the end of the natural rubber molecule to modify the natural rubber, so as to reduce the hysteresis loss and heat build-up, improve the elasticity, and obtain the low heat build-up modified natural rubber. The addition amount of isophthalic dihydrazide is 0.5 phr; Graphene oxide, with an average particle size of 3 μm and an interlayer spacing of 4-20 angstroms; Si69, bis-(γ-triethoxysilylpropyl) tetrasulfide, CAS:40372-72-3; Mercaptopropyl triethoxysilane, 3-mercapto propyl triethoxysilane, CAS:14814-09-06; Vinyl trimethoxysilane, CAS:2768-02-7; Alumina whisker, with a size of 4.93 μm x 0.54 μm and a purity of ≥99.9%; Alumina microspheres, with an average particle size of 1 μm and a purity of ≥99.9%; Hydroxyl-terminated polybutadiene, selected from Jining Huakai Resin Co., Ltd., type II HTPB, CAS:69102-90-5; Microcrystalline wax, selected from Jinan Yunuo Chemical Co., Ltd., CAS:2768-02-7.

[0033] Preparation examples 1.1-1.8 of graphene modified filler Preparation example 1.1 The graphene modified filler is prepared by the following steps: S1: 5 g of graphene oxide is dispersed in 500 mL of water, and a suspension is formed after ultrasonic dispersion for 45 min; S2: adding acetone into the suspension successively, ultrasonic for 10 min, the mass ratio of the suspension and acetone is 1:0.5, then adding boric acid and urea with a molar ratio of 1:7, stirring to form a homogeneous system, reacting for 12 h at 180℃, in-situ generating boron nitride nanosheets on the surface of graphene oxide, then cooling to 70℃, adjusting pH to 4±0.5 with hydrochloric acid, adding mercaptopropyl triethoxysilane dropwise, the addition amount is 15% of the mass of graphene oxide, after stirring for 6 h at constant temperature, centrifuging, washing and drying to obtain graphene modified filler coated with boron nitride nanosheets, the mass ratio of the generated boron nitride nanosheets to graphene oxide is 1:0.5.

[0034] Preparation Example 1.2 The graphene modified filler is prepared by the following steps: S1: dispersing 5 g of graphene oxide in 500 mL of water, ultrasonic dispersion for 45 min to form a suspension; S2: adding acetone into the suspension successively, ultrasonic for 10 min, the mass ratio of the suspension and acetone is 1:0.5, then adding boric acid and urea with a molar ratio of 1:7, stirring to form a homogeneous system, reacting for 18 h at 200℃, in-situ generating boron nitride nanosheets on the surface of graphene oxide, then cooling to 75℃, adjusting pH to 4±0.5 with hydrochloric acid, adding mercaptopropyl triethoxysilane dropwise, the addition amount is 15% of the mass of graphene oxide, after stirring for 5.5 h at constant temperature, centrifuging, washing and drying to obtain graphene modified filler coated with boron nitride nanosheets, the mass ratio of the generated boron nitride nanosheets to graphene oxide is 1:1.16.

[0035] Preparation Example 1.3 The graphene modified filler is prepared by the following steps: S1: dispersing 5 g of graphene oxide in 500 mL of water, ultrasonic dispersion for 45 min to form a suspension; S2: adding acetone into the suspension successively, ultrasonic for 10 min, the mass ratio of the suspension and acetone is 1:0.5, then adding boric acid and urea with a molar ratio of 1:7, stirring to form a homogeneous system, reacting for 24 h at 220℃, in-situ generating boron nitride nanosheets on the surface of graphene oxide, then cooling to 80℃, adjusting pH to 4±0.5 with hydrochloric acid, adding mercaptopropyl triethoxysilane dropwise, the addition amount is 15% of the mass of graphene oxide, after stirring for 5 h at constant temperature, centrifuging, washing and drying to obtain graphene modified filler coated with boron nitride nanosheets, the mass ratio of the generated boron nitride nanosheets to graphene oxide is 1:1.5.

[0036] Preparation Example 1.4 Graphene-modified filler, the difference between Preparation Example 1.1 only lies in the mass ratio between the generated product boron nitride nanosheet and graphene oxide is 1:0.35.

[0037] Preparation Example 1.5 Graphene-modified filler, the difference between Preparation Example 1.3 only lies in the mass ratio between the generated product boron nitride nanosheet and graphene oxide is 1:1.8.

[0038] Preparation Example 1.6 Graphene-modified filler, the difference between Preparation Example 1.1 only lies in the mass ratio between the generated product boron nitride nanosheet and graphene oxide is 1:0.35.

[0039] Preparation Example 1.7 Graphene-modified filler, the preparation method comprises the following steps: S1: 5g of graphene oxide and 2.5g of boron nitride are dispersed in 750mL of water, and a mixed suspension is formed after ultrasonic dispersion for 45min; S2: the pH of the mixed suspension is adjusted to 4±0.5 with hydrochloric acid, and mercaptopropyl triethoxysilane is added dropwise, the amount of which is 15% of the mass of graphene oxide, and after constant temperature stirring for 6h, centrifugation, washing and drying are carried out to obtain the graphene-modified filler.

[0040] Preparation Example 1.8 Graphene-modified filler, the preparation method comprises the following steps: S1: 5g of graphene oxide is dispersed in 500mL of water, and a suspension is formed after ultrasonic dispersion for 45min; S2: the pH of the suspension is adjusted to 4±0.5 with hydrochloric acid, and mercaptopropyl triethoxysilane is added dropwise, the amount of which is 15% of the mass of graphene oxide, and after constant temperature stirring for 6h, centrifugation, washing and drying are carried out to obtain the graphene-modified filler.

[0041] Preparation Examples 2.1-2.4 of modified alumina whiskers Preparation Example 2.1 Modified alumina whisker, the preparation method comprises the following steps: S1: triethylamine is dissolved in anhydrous ethanol to prepare a 3wt% triethylamine solution, and alumina whiskers are added to the triethylamine solution according to a solid-liquid ratio of 1:15, and a transition layer of bonding agent is formed on the surface of the alumina whiskers after stirring at room temperature for 4h, and then centrifugation, washing and drying are carried out to obtain a modified alumina whisker intermediate; S2: The hydroxyl-terminated polybutadiene was dissolved in toluene to prepare a 10 wt% hydroxyl-terminated polybutadiene solution, and the modified alumina whisker intermediate was added into the hydroxyl-terminated polybutadiene solution at a solid-liquid ratio of 1:10. After stirring at room temperature for 8 h under nitrogen protection, centrifugation, washing, and drying were performed to obtain the modified alumina whisker.

[0042] Preparation Example 2.2 A modified alumina whisker, a preparation method thereof, comprising the following steps: S1: Triethylamine was dissolved in anhydrous ethanol to prepare a 4 wt% triethylamine solution, and alumina whiskers were added into the triethylamine solution at a solid-liquid ratio of 1:15. After stirring at room temperature for 3 h, a transition layer of the bonding agent was formed on the surface of the alumina whiskers. After centrifugation, washing, and drying, a modified alumina whisker intermediate was obtained; S2: The hydroxyl-terminated polybutadiene was dissolved in toluene to prepare a 12 wt% hydroxyl-terminated polybutadiene solution, and the modified alumina whisker intermediate was added into the hydroxyl-terminated polybutadiene solution at a solid-liquid ratio of 1:10. After stirring at room temperature for 7 h under nitrogen protection, centrifugation, washing, and drying were performed to obtain the modified alumina whisker.

[0043] Preparation Example 2.3 A modified alumina whisker, a preparation method thereof, comprising the following steps: S1: Triethylamine was dissolved in anhydrous ethanol to prepare a 5 wt% triethylamine solution, and alumina whiskers were added into the triethylamine solution at a solid-liquid ratio of 1:15. After stirring at room temperature for 2 h, a transition layer of the bonding agent was formed on the surface of the alumina whiskers. After centrifugation, washing, and drying, a modified alumina whisker intermediate was obtained; S2: The hydroxyl-terminated polybutadiene was dissolved in toluene to prepare a 15 wt% hydroxyl-terminated polybutadiene solution, and the modified alumina whisker intermediate was added into the hydroxyl-terminated polybutadiene solution at a solid-liquid ratio of 1:10. After stirring at room temperature for 6 h under nitrogen protection, centrifugation, washing, and drying were performed to obtain the modified alumina whisker.

[0044] Preparation Example 2.4 A modified alumina, a preparation method thereof, comprising the following steps: S1: Triethylamine was dissolved in anhydrous ethanol to prepare a 3 wt% triethylamine solution, and alumina microspheres were added into the triethylamine solution at a solid-liquid ratio of 1:15. After stirring at room temperature for 4 h, a transition layer of the bonding agent was formed on the surface of the alumina microspheres. After centrifugation, washing, and drying, a modified alumina microsphere intermediate was obtained; S2: The hydroxyl-terminated polybutadiene was dissolved in toluene to prepare a 10 wt% hydroxyl-terminated polybutadiene solution, and the modified alumina microsphere intermediate was added into the hydroxyl-terminated polybutadiene solution at a solid-liquid ratio of 1:10. After stirring at room temperature for 8 h under nitrogen protection, centrifugation, washing, and drying were performed to obtain the modified alumina. Example

[0045] Example 1 A high-thermal-conductivity and high-heat-dissipation rubber composition, each raw material and the amount are shown in Table 1, wherein the thermal superconducting filler comprises graphene modified filler and modified alumina whisker with a mass ratio of 1.5:1, the graphene modified filler is obtained by preparation example 1.1, and the modified alumina whisker is obtained by preparation example 2.1.

[0046] Table 1 The preparation method of the above high-thermal-conductivity and high-heat-dissipation rubber composition, comprising the following steps: S1: The graphene modified filler and the modified alumina whisker are mixed and dispersed at a speed of 2 million r / min at 100±5℃ for 5min to obtain a thermal superconducting filler according to the raw material ratio; S2: The raw materials are weighed according to the weight parts, and the natural rubber wet rubber T-145 and the low-heat-generation modified natural rubber NRX-X1 are mixed, and the masterbatch is obtained after mixing at 140℃ for 10min; S3: The masterbatch, high-dispersion white carbon black 1165MP, carbon black N660, Si69, Sylvatraxx 4150 paraffin resin tackifier, thermal superconducting filler, zinc oxide, stearic acid, antioxidant DTPD, antioxidant RD, antioxidant 4020 and microcrystalline wax are continuously mixed at 140℃ for 15min, and then put into the open mill to add accelerator DPG, accelerator CZ, anti-scorching agent CTP and sulfur and open for 5min to form the rubber compound; S4: The rubber compound is placed for 8h, and then vulcanized on a flat vulcanizing agent at 150℃ and 8MPa for 21min, and the vulcanized product is obtained.

[0047] Example 2 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from example 1 in that each raw material and the amount are shown in Table 1, wherein the thermal superconducting filler comprises graphene modified filler and modified alumina whisker with a mass ratio of 2:1, and the preparation method of the above high-thermal-conductivity and high-heat-dissipation rubber composition, comprising the following steps: S1: The graphene modified filler and the modified alumina whisker are mixed and dispersed at a speed of 2 million r / min at 100±5℃ for 5min to obtain a thermal superconducting filler according to the raw material ratio; S2: The raw materials are weighed according to the weight parts, and the natural rubber wet rubber T-145 and the low-heat-generation modified natural rubber NRX-X1 are mixed, and the masterbatch is obtained after mixing at 145℃ for 8min; S3: continue mixing the masterbatch with high-dispersion white carbon black 1165MP, carbon black N660, Si69, Sylvatraxx 4150 paraffin wax tackifier, thermal superconducting filler, zinc oxide, stearic acid, antioxidant DTPD, antioxidant RD, antioxidant 4020 and microcrystalline wax at 145℃ for 13 min, then put it on an open mill to add accelerator DPG, accelerator CZ, anti-scorching agent CTP and sulfur and mix for 5 min to form a rubber compound; S4: place the rubber compound for 8 h, then vulcanize it on a flat vulcanizer at 155℃ and 9 MPa for 18 min, and obtain the product.

[0048] Example 3 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the raw materials and their amounts are shown in Table 1, wherein the thermal superconducting filler comprises graphene modified filler and modified alumina whisker at a mass ratio of 2.5:1, and the preparation method of the high-thermal-conductivity and high-heat-dissipation rubber composition comprises the following steps: S1: mix and disperse the graphene modified filler and the modified alumina whisker at a high speed of 20,000 r / min for 5 min at 100±5℃ to obtain the thermal superconducting filler; S2: weigh the raw materials according to the weight parts, mix the natural rubber wet rubber T-145 and the low-heat-buildup modified natural rubber NRX-X1, and mix them at 150℃ for 7 min to obtain a masterbatch; S3: continue mixing the masterbatch with high-dispersion white carbon black 1165MP, carbon black N660, Si69, Sylvatraxx 4150 paraffin wax tackifier, thermal superconducting filler, zinc oxide, stearic acid, antioxidant DTPD, antioxidant RD, antioxidant 4020 and microcrystalline wax at 150℃ for 11 min, then put it on an open mill to add accelerator DPG, accelerator CZ, anti-scorching agent CTP and sulfur and mix for 5 min to form a rubber compound; S4: place the rubber compound for 8 h, then vulcanize it on a flat vulcanizer at 160℃ and 10 MPa for 15 min, and obtain the product.

[0049] Example 4 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the graphene modified filler in the thermal superconducting filler is prepared by Preparation Example 1.2, the modified alumina whisker is prepared by Preparation Example 2.2, and the other steps are the same as those of Example 1.

[0050] Example 5 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the graphene modified filler in the thermal superconducting filler is prepared by Preparation Example 1.3, the modified alumina whisker is prepared by Preparation Example 2.3, and the other steps are the same as those of Example 1.

[0051] Example 6 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the graphene modified filler in the thermal superconducting filler is prepared by Preparation Example 1.4, and other steps are the same as Example 1.

[0052] Example 7 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the graphene modified filler in the thermal superconducting filler is prepared by Preparation Example 1.5, and other steps are the same as Example 1.

[0053] Example 8 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the graphene modified filler in the thermal superconducting filler is prepared by Preparation Example 1.6, and other steps are the same as Example 1.

[0054] Example 9 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the graphene modified filler in the thermal superconducting filler is prepared by Preparation Example 1.7, and other steps are the same as Example 1.

[0055] Example 10 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the modified alumina whisker in the thermal superconducting filler is replaced by an equal amount of unmodified alumina whisker, and other steps are the same as Example 1.

[0056] Example 11 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the thermal superconducting filler includes graphene modified filler and modified alumina whisker in a mass ratio of 1.2:1, and other steps are the same as Example 1.

[0057] Example 12 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 3 in that the thermal superconducting filler includes graphene modified filler and modified alumina whisker in a mass ratio of 3:1, and other steps are the same as Example 3.

[0058] Comparative Example Comparative Example 1 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that the graphene modified filler in the thermal superconducting filler is prepared by Preparation Example 1.8, and other steps are the same as Example 1.

[0059] Comparative Example 2 A high-thermal-conductivity and high-heat-dissipation rubber composition, which is different from Example 1 in that no modified alumina whisker is added, and the thermal superconducting filler is only graphene modified filler, and other steps are the same as Example 1.

[0060] Comparative Example 3 A high-thermal-conductivity heat-dissipation rubber composition, which is different from Example 1 in that the modified alumina whiskers in the thermal superconductive filler are replaced with equal mass of modified alumina prepared from Preparation Example 2.4, and other steps are the same as those in Example 1.

[0061] Comparative Example 4 A high-thermal-conductivity heat-dissipation rubber composition, which is different from Comparative Example 3 in that the modified alumina whiskers in the thermal superconductive filler are replaced with equal mass of unmodified alumina microspheres, and other steps are the same as those in Comparative Example 3.

[0062] Performance detection test The high-thermal-conductivity heat-dissipation rubber compositions prepared from Examples 1-12 and Comparative Examples 1-4 are subjected to the following relevant performance detection tests, each group of tests is performed for 3 times, the average value of the test results of the 3 times is taken as the final result and the final result is recorded in Table 2.

[0063] 1. Thermal conductivity performance: the thermal conductivity is detected according to the relevant provisions of GB / T 11205-2009 “Determination of Thermal Conductivity of Rubber by Hot-Wire Method”; 2. Tensile strength: the tensile strength is detected according to the relevant provisions in GB / T 528-2009 “Determination of Tensile Stress-Strain Properties of Vulcanized or Thermoplastic Rubber”; 3. Tear strength: the tear strength is detected according to the relevant provisions of GB / T 529-2008 “Determination of Tear Strength of Vulcanized or Thermoplastic Rubber (Pants, Right Angle and Crescent Shape Specimens)” using the crescent shape specimen.

[0064] Table 2 According to the performance detection results of Examples 1 and Comparative Examples 1-2 in Table 2, it can be seen that when the heterostructure graphene modified filler formed by depositing boron nitride nanosheets on the surface of graphene oxide in a liquid phase in situ growth manner is mixed with the one-dimensional structure modified alumina whiskers as the thermal superconductive filler, the alumina whiskers play a role of longitudinal bridge and link in the graphene modified filler, and a complete, continuous and efficient three-dimensional thermal conduction network structure is constructed, the thermal conductivity reaches 0.70 W / m·K or more, the thermal conduction efficiency is greatly improved, a very small amount of addition will have a very significant effect on the improvement of the thermal conductivity of the material, and the mechanical properties of the material are also significantly improved, overcoming the problem that the mechanical properties are sacrificed due to the improvement of the thermal conductivity in the prior art, and the prepared rubber product can meet the rapid heat dissipation requirements of military vehicles in extreme environments, especially in the state of high load and high speed.

[0065] According to the performance detection results of Example 1, Example 9 and Comparative Example 1, it can be seen that, based on graphene oxide sheet, a rapid heat conduction channel can be formed in the two-dimensional plane, and the hetero three-dimensional structure formed by the in-situ vertical growth of boron nitride nanosheet on the surface can efficiently conduct heat from the rubber matrix to the graphene oxide and further conduct heat, and can also vertically conduct heat from the graphene oxide to other fillers and interfaces, so as to realize the isotropic and efficient three-dimensional heat conduction network by the synergistic effect between the physical structures and heat conduction properties of different fillers, and significantly improve the mechanical properties of the material. The heat generated by the rubber can be quickly conducted and conducted out of the material, which cannot be achieved by simple physical mixing or single layered graphene oxide as a filler. The scheme of using physically mixed composite heat-conducting fillers not only cannot significantly improve the heat conduction efficiency of the material, but also may sacrifice the mechanical properties of the material.

[0066] According to the data of Examples 1-7, it can be seen that, when the mass ratio of boron nitride nanosheet to graphene oxide is in the range of 1:(0.5-1.5), the performance of the obtained rubber product is optimal.

[0067] In Example 8, vinyltrimethoxysilane is used instead of mercaptopropyltriethoxysilane as a compatibilizing modifier. It can be seen that the thermal conductivity and mechanical properties of the rubber product are not as good as those of Example 1. This is because when mercaptopropyltriethoxysilane is used as a compatibilizing modifier, a small amount of mercapto groups can be coordinated with alumina whiskers during subsequent mixing, which promotes the connection stability between metal components and non-metal components, increases the continuity of the heat conduction path, and makes the three-dimensional heat conduction network structure formed by mixing the heterostructure graphene filler and the one-dimensional modified alumina whisker more stable.

[0068] According to the performance detection results of Example 1, Example 10 and Comparative Examples 2-4, it can be seen that the scheme of replacing alumina whisker with alumina microspheres is obviously insufficient in improving the heat conduction performance of the material. As a one-dimensional linear filler, alumina whisker plays a role of vertical bridge and link between heterostructure graphene fillers, and cooperatively constructs a complete and continuous heat conduction network and a more stable mechanical structure, which cannot be achieved by spherical alumina microspheres, thereby greatly improving the heat conduction efficiency of the heat conduction path and the mechanical properties of the rubber product.

[0069] By grafting HTPB on the surface of alumina, the compatibility between the metal component and the rubber matrix and the graphene modified filler can be effectively enhanced, and the introduction of long molecular chains further realizes the flexible transition from the surface of the rigid filler to the flexible rubber matrix, thereby greatly reducing the stress concentration and improving the toughness and mechanical properties of the rubber product.

[0070] It can be seen from the performance test results of Examples 1-5 and Examples 11-12 that when the mass ratio between the graphene modified filler and the alumina whisker is in the range of (1.5-2.5):1, the various performances of the rubber product are optimal.

[0071] The specific embodiments are only illustrative of the present application, and are not intended to limit the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high thermal conductive and heat dissipative rubber composition, characterized by, The raw materials include 120-125 parts of rubber base material, 35-45 parts of carbon black, 1-3 parts of thermal superconducting filler, 1-2 parts of sulfur, 3-4 parts of accelerator, 4-7 parts of activator and 3-4 parts of antioxidant by weight; The thermal superconducting filler includes graphene modified filler and alumina whisker.

2. The high thermally conductive heat dissipating rubber composition according to claim 1, characterized in that, The raw materials of the rubber base material include natural rubber wet glue and low-heat generation modified natural rubber.

3. The high thermally conductive rubber composition of claim 1, wherein, The mass ratio between the graphene modified filler and the alumina whisker is (1.5-2.5):

1.

4. The high thermally conductive rubber composition of claim 1, wherein, The preparation method of the graphene modified filler includes the following steps: Disperse graphene oxide in water to form a suspension by ultrasonic; Add organic solvent, boron source and nitrogen source to the suspension, stir to form a homogeneous system, then react at 180-220℃ to generate boron nitride nanosheet in situ on the surface of graphene oxide, then cool to 70-80℃, drop compatible modifier, constant temperature stirring reaction, then centrifuge, wash, dry to obtain graphene modified filler coated with boron nitride nanosheet on the surface.

5. The high thermally conductive heat dissipating rubber composition according to claim 4, characterized in that, The mass ratio between the boron nitride nanosheet and the graphene oxide is 1:(0.5-1.5).

6. The high thermally conductive heat dissipating rubber composition according to claim 4, characterized in that, The compatible modifier is mercaptopropyl triethoxysilane.

7. The high thermally conductive rubber composition of claim 1, wherein, The alumina whisker is modified alumina whisker with polybutadiene grafted on the surface.

8. The high thermally conductive rubber composition of claim 7, wherein, The preparation method of the modified alumina whisker includes the following steps: Add alumina whisker to 3-5wt% triethylamine solution, stir to react, then centrifuge, wash and dry to obtain modified alumina whisker intermediate; Add the modified alumina whisker intermediate to 10-15wt% hydroxyl-terminated polybutadiene solution, stir to react under nitrogen protection, then centrifuge, wash and dry to obtain the modified alumina whisker.

9. Process for the preparation of the high thermally conductive heat dissipating rubber composition according to any one of claims 1 to 8, characterized in that, The preparation method includes the following steps: Weigh the raw materials by weight parts, mix the rubber base material, carbon black, thermal superconducting filler, activator and antioxidant at 140-150℃, then add accelerator and sulfur to open the rubber to form rubber compound, then let the rubber compound stand, then vulcanize at 150-160℃, and the rubber compound is obtained.

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