Efficient preparation process for high-modulus graphene oxide / natural rubber uniformly-cured solid load-bearing tire

Abstract

The present invention relates to the technical fields of graphene and functional natural rubber, and in particular relates to high-modulus graphene oxide / natural rubber and an efficient preparation process for a uniformly-cured solid load-bearing tire thereof. The rubber is prepared from the following raw materials in parts by mass: 100 parts of natural rubber, 40-120 parts of carbon black, 0.5-5 parts of graphene oxide, 1-20 parts of an activating agent, 1-20 parts of a softening agent, 1-10 parts of an anti-aging agent, 1-10 parts of an antioxidant, 1-20 parts of a vulcanization accelerator, 1-20 parts of a vulcanizing agent, and 1-20 parts of an interface modifier. Firstly, the hardness and mechanical properties of a rubber composite material are improved, and a tire formed therefrom has a low dynamic heat generation value during a driving process, thus slowing down the aging failure of a load-bearing tire; secondly, a rubber strip prepared from a graphene oxide / carbon black / natural rubber mixed rubber sheet of a 'sandwich structure' consisting of high-viscosity upper and lower layers and a high-modulus middle layer is attached and wound on a hub, thereby effectively solving the problem of poor bonding between high-modulus rubber layers; and thirdly, by means of a step-by-step vulcanization process, various properties of the solid tire for a loading wheel are further improved, and the service life is thus prolonged.

Description

Efficient preparation process of high modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202410067427.7, filed with the Chinese Patent Office on January 17, 2024, entitled "Efficient Preparation Process for High Modulus Graphene Oxide / Natural Rubber Uniformly Cured Solid Load-Bearing Tires," the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of graphene and functional natural rubber composite materials, and in particular to an efficient preparation process for a high-modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire. Background Art

[0004] Rubber is an important strategic material with unique viscoelasticity and is widely used in industry and defense. Natural rubber (NR) has excellent elasticity, wear resistance, anti-aging properties and corrosion resistance, making it one of the ideal materials for preparing solid rubber tires. However, due to its low hardness, NR deforms greatly when subjected to external forces. On the one hand, it cannot carry heavy engineering equipment, and on the other hand, it is very easy to produce microcracks, leading to damage and failure, thereby reducing the service life of the tire. The commonly used method to solve this problem is to add inorganic fillers such as carbon black to improve the mechanical properties of NR composite materials. However, with the continuous advancement of science and technology, more stringent requirements are placed on the performance of rubber composite materials.

[0005] In order to further improve the performance of NR, nanoparticles such as ceramic particles, nanodiamonds, carbon nanotubes and graphene (GE) have become ideal fillers for reinforcing the rubber matrix due to their small size and large specific surface area. Among them, GE and its derivatives are considered to be the most ideal fillers for NR composites and are often used to improve mechanical, electrical, thermal and chemical properties. As an important representative of GE derivatives, graphene oxide (GO) is rich in oxygen-containing groups such as hydroxyl, epoxy, carboxyl and carbonyl groups on its surface, which gives it hydrophilicity, making it easy to disperse evenly in natural rubber latex. At the same time, these oxygen functional groups are beneficial to improving the interfacial interaction between GO and the NR matrix. Therefore, it is widely used to reinforce modified rubber, thereby improving the safety, durability and performance of molded solid tires.

[0006] High-modulus rubber composites are widely used in rubber products such as tire apex rubber, automotive drive belts, and road wheels. As heavy-duty vehicles move toward heavier loads and higher speeds, the shear, tension, compression, and torsion forces on the road wheel rubber body become more intense. Consequently, solid rubber tires experience significant temperature rises during operation, making them susceptible to problems such as high-temperature cracking, chipping, and fragmentation. This is especially true when driving on complex surfaces, where solid rubber tires suffer from poor cut resistance. Therefore, solid tire tread compounds must possess a combination of excellent properties, including high modulus, low dynamic heat generation, high fatigue resistance, high strength, and tear resistance, to meet these requirements.

[0007] The degree of vulcanization in different parts of solid rubber tires, as well as the determination of the vulcanization time for thick products, have long been a focus of attention. Because rubber is a poor conductor of heat, as the thickness of the product increases, the rubber compound is not heated evenly and synchronously. This causes the internal and external temperature gradient to increase with the thickness of the rubber layer. This results in significantly different degrees of vulcanization between the internal and external rubber compounds at the same vulcanization time. Therefore, when determining the vulcanization process parameters, the first thing to do is to ensure that the rubber compound in each part is fully vulcanized, that is, there is no under-vulcanization inside and no over-vulcanization outside. Under this premise, it is also necessary to determine the shortest vulcanization time to improve production efficiency while ensuring product quality.

[0008] Summary of the Invention

[0009] The present invention overcomes the deficiencies of the prior art and provides an efficient preparation process for a high-modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire.

[0010] To solve the above technical problems, the technical solution adopted by the present invention is: an efficient preparation process for high modulus graphene oxide / natural rubber and its uniformly cured solid load-bearing tire, wherein the high modulus graphene oxide / natural rubber is made from the following raw materials in the following mass ratios:

[0011] 100 parts of natural rubber, 40-120 parts of carbon black (CB), 0.5-5 parts of graphene oxide, 1-20 parts of activator, 1-20 parts of softener, 1-10 parts of antioxidant, 1-10 parts of antioxidant, 1-20 parts of vulcanization accelerator, 1-20 parts of vulcanizing agent, and 1-20 parts of interface modifier;

[0012] The preparation process includes the following steps:

[0013] (1) adding deionized water to the graphene oxide slurry, and obtaining a uniform aqueous dispersion of graphene oxide by ultrasonic dispersion;

[0014] (2) adding the graphene oxide uniform aqueous dispersion obtained in step (1) to natural rubber latex, stirring and mixing thoroughly to obtain a uniformly dispersed mixed emulsion; adding a flocculant to break the emulsion to obtain raw rubber, washing, dehydrating, and drying to obtain a graphene oxide / natural rubber masterbatch;

[0015] (3) The graphene oxide / natural rubber masterbatch obtained in step (2) is placed in an internal mixer for internal mixing, and carbon black, an interfacial modifier, an anti-aging agent, an antioxidant, a vulcanization accelerator, an activator, and a softener are added in sequence. After the internal mixing time A, the rubber material is discharged and cooled to room temperature. The rubber material is then mixed on an open mixer for an internal mixing time A, a vulcanizing agent is added, and after uniform mixing, the rubber material is thinly passed until there are no bubbles in the rubber material to obtain a high modulus graphene oxide / carbon black / natural rubber mixed rubber and pressed into a film;

[0016] (4) The graphene oxide / natural rubber masterbatch obtained in step (2) is placed in an internal mixer for internal mixing, and carbon black, an interfacial modifier, an anti-aging agent, an antioxidant, a vulcanization accelerator, an activator, and a softener are added in sequence. After the internal mixing time B, the rubber material is discharged and cooled to room temperature. The rubber material is then mixed on an open mixer for time B, a vulcanizing agent is added, and after uniform mixing, the rubber material is thinly passed until there are no bubbles in the rubber material to obtain a high-viscosity graphene oxide / carbon black / natural rubber mixed rubber and pressed into a film;

[0017] (5) placing the high modulus graphene oxide / carbon black / natural rubber mixed rubber sheet obtained in step (3) between the upper and lower high viscosity graphene oxide / carbon black / natural rubber mixed rubber sheets obtained in step (4) to form a "sandwich structure" mixed rubber, and after standing for a certain period of time, forming a "sandwich structure" rubber strip with a width smaller than the width of the metal hub;

[0018] (6) applying adhesive to the surface of the metal hub of the road wheel and drying it, and then wrapping the "sandwich structure" rubber strip prepared in step (5) around the surface of the metal hub, with the wrapping thickness being the designed thickness of the road wheel rubber layer;

[0019] (7) The metal wheel hub wrapped with the "sandwich structure" rubber strip obtained in step (6) is placed in a road wheel mold and vulcanized in steps, with the first step being vulcanization at high temperature for time C and the second step being vulcanization at low temperature for time D, to obtain a uniformly cured solid load-bearing tire of high modulus graphene oxide / natural rubber. As a further improvement to the technical solution of the present invention, the interfacial modifier is selected from at least one of Si69, Si75, Si75-ES, and Si264.

[0020] As a further improvement of the technical solution of the present invention, the vulcanization accelerator is N-tert-butyl-2-benzothiazole sulfenamide, N-cyclohexyl-2-benzothiazole sulfenamide or N-(diethylene oxide)-2-benzothiazole sulfenamide; the antioxidant is 2,6-di-tert-butyl-4-methylphenol, 2,2,4-trimethyl-1,2-dihydroquinoline polymer or 2-thiol benzoimidazole; the antioxidant is N-(1-methylisopentyl)-N'-phenyl-p-phenylenediamine, p-phenylaniline or dilauryl dipropionate sulfide; the activator is zinc gluconate, zinc oxide or magnesium oxide; the softener is stearic acid, dibutyl titanate or dioctyl adipate; and the vulcanizing agent is sulfur or sulfur monochloride.

[0021] As a further improvement of the technical solution of the present invention, in step (1), the power of the ultrasonic dispersion is 100 to 300 W, the time of the ultrasonic dispersion is 5 to 20 min, and the concentration of the obtained graphene oxide uniform aqueous dispersion is 2 to 6 mg / mL.

[0022] As a further improvement of the technical solution of the present invention, in step (3), the mixing temperature in the internal mixer is 110-120° C., and the mixing time A is 5-12 min; the mixing temperature in the open mixer is 50-80° C., and the mixing time A is 6-15 min; the mass ratio of the graphene oxide in step (1), the rubber solids in the natural latex in step (2), and the carbon black, interfacial modifier, antioxidant, antioxidant, vulcanization accelerator, activator, softener and vulcanizing agent in step (3) is 0.5-5:100:40-120:1-20:1-10:1-10:1-20:1-20:1-20:1-20:1-20.

[0023] As a further improvement of the technical solution of the present invention, in step (4), the mixing temperature in the internal mixer is 110-120° C., and the mixing time B is 5-12 min; the mixing temperature in the open mixer is 50-80° C., and the mixing time B is 15-25 min; the mass ratio of the graphene oxide in step (1), the rubber solids in the natural latex in step (2), and the carbon black, interfacial modifier, antioxidant, antioxidant, vulcanization accelerator, activator, softener and vulcanizing agent in step (4) is 0.5-5:100:40-120:1-20:1-10:1-10:1-20:1-20:1-20:1-20:1-20.

[0024] As a further improvement of the technical solution of the present invention, in step (5), the thickness of the middle layer of the high modulus mixed film of the "sandwich structure" mixed film is 3 to 6 mm, the thickness of the upper layer of the high viscosity mixed film is 0.3 to 1 mm, and the thickness of the lower layer of the high viscosity mixed film is 0.3 to 1 mm; the stop time is 20 to 30 hours.

[0025] As a further improvement of the technical solution of the present invention, in step (6), the adhesive is a general adhesive selected from at least one of Chemlok 6125, Chemlok 205 and Chemlok 6150.

[0026] As a further improvement of the technical solution of the present invention, in step (7), the vulcanization pressure is 10-25 MPa, the first step vulcanization temperature is 150-170°C, the vulcanization time C is 2-6 min, the second step vulcanization temperature is 140-150°C, and the vulcanization time D is 10-30 min.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1) In the present invention, carbon black and graphene are used together as two reinforcing fillers in conjunction with an in-situ interfacial modification process to improve their dispersibility in rubber and their interfacial interaction with the rubber, thereby improving the hardness and mechanical properties of the composite material while ensuring that the molded tire has a low dynamic heat generation value during driving, thereby slowing down the aging and failure of the load-bearing tire.

[0029] 2) The interfacial modifier in this invention serves two purposes: first, it improves the dispersion of carbon black and GO in the NR matrix. Dispersion of reinforcing fillers in rubber is crucial for improving the performance of the composite. Silane coupling agents improve the surface properties of carbon black and GO, enhancing their compatibility with NR and, in turn, their interfacial interaction with rubber. Second, the interfacial modifier chemically reacts with the NR matrix to form a vulcanized crosslinked network, improving the bond strength between the filler and rubber, and enhancing the mechanical properties and durability of the composite.

[0030] 3) Compared to other tire production processes, this invention utilizes a highly efficient and industrially feasible aqueous phase co-precipitation process to prepare a well-dispersed GO / NR masterbatch. This process is followed by mechanical blending to produce a GO / CB / NR rubber mix, which is then vulcanized to produce a solid roadwheel tire. Each of these steps can be prepared using conventional processes; the materials involved are environmentally friendly and inexpensive; and the equipment is simple to operate, making it readily scalable.

[0031] 4) The present invention utilizes a "sandwich structure" mixed rubber sheet in conjunction with a step-by-step vulcanization process to improve the vulcanization effect of solid rubber tires. The first step utilizes high-temperature vulcanization to improve the fluidity of the rubber compound and reduce defects in the load-bearing tire. The second step utilizes low-temperature vulcanization to completely vulcanize the rubber compound without causing a decrease in mechanical properties due to over-sulfurization, thereby ensuring that the product obtains optimal vulcanization uniformity, and the molded solid rubber tire has excellent mechanical properties, thereby further improving the service life of the natural rubber road wheel solid tire. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a digital photograph of a high modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire molded in Example 1. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to specific embodiments.

[0034] The raw materials used in the examples are all conventional commercially available raw materials.

[0035] Table 1 Test standards used for performance characterization

[0036] A high modulus graphene oxide / natural rubber is prepared from natural rubber, reinforcing filler carbon black and graphene oxide, an activator, a softener, an antioxidant, an antioxidant, a vulcanization accelerator, a vulcanizing agent, and an interface modifier;

[0037] The specific formula is:

[0038] Example 1

[0039] An efficient preparation process for a uniformly cured solid load-bearing tire of high modulus graphene oxide / natural rubber comprises the following steps:

[0040] (1) Weigh 50 g of 10 mg / mL graphene oxide (GO) slurry, add 50 g of deionized water, and sonicate at 200 W for 15 min to obtain a 5 mg / mL graphene oxide uniform aqueous dispersion;

[0041] (2) Weighing 166.7 g of natural rubber latex with a solid content of 60 wt.%, adding the uniform aqueous dispersion of graphene oxide obtained in step (1), and mixing thoroughly to obtain a uniformly dispersed mixed emulsion; adding 60 g of a 10 wt.% CaCl2 solution to the mixed solution to break the emulsion to obtain raw rubber, washing, dehydrating, and drying to obtain a graphene oxide / natural rubber masterbatch;

[0042] (3) The graphene oxide / natural rubber masterbatch obtained in step (2) is placed in an internal mixer and mixed at 110°C for 4 minutes. 2g of antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer, 2g of antioxidant N-(1-methylisopentyl)-N'-phenyl-p-phenylenediamine and 2g of vulcanization accelerator N-(oxydiethylene)-2-benzothiazolesulfonamide are added in sequence and the mixing is continued for 4 minutes. 85g of carbon black, 5g of interface modifier Si69, 5g of activator ZnO and 2g of softener stearic acid are added and the mixing is continued for 4 minutes. After the rubber is evenly mixed, the rubber is discharged. After the rubber is cooled to room temperature, it is transferred to an open mixer for mixing at 60°C. 2g of sulfur is added during the mixing process. After mixing for 6 minutes, the rubber is thinned until there are no bubbles in the rubber to obtain a high modulus graphene oxide / carbon black / natural rubber mixed rubber and pressed into a 5mm thick film.

[0043] (4) The graphene oxide / natural rubber masterbatch obtained in step (2) is placed in an internal mixer and mixed at 110° C. for 4 min. 2 g of antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer, 2 g of antioxidant N-(1-methylisopentyl)-N'-phenyl-p-phenylenediamine and 2 g of vulcanization accelerator N-(oxydiethylene)-2-benzothiazolesulfonamide are added in sequence and the mixing is continued for 4 min. 85 g of carbon black, 5 g of interface modifier Si69, 5 g of activator ZnO and 2 g of softener stearic acid are added and the mixing is continued for 4 min. After the rubber is mixed evenly, the rubber is discharged. After the rubber is cooled to room temperature, it is transferred to an open mixer and mixed at 60° C. 2 g of sulfur is added during the mixing process. After mixing evenly for 15 min, the rubber is thinly passed until there are no bubbles in the rubber to obtain a high-viscosity graphene oxide / carbon black / natural rubber mixed rubber and pressed into a 0.3 mm thick film.

[0044] (5) placing the high modulus graphene oxide / carbon black / natural rubber compound rubber sheet obtained in step (3) between the upper and lower high viscosity graphene oxide / carbon black / natural rubber compound rubber sheets obtained in step (4) to form a "sandwich structure" compound rubber, and making a rubber strip with a width of 30 mm after standing for 20 hours;

[0045] (6) Apply Chemlock 205 adhesive to the surface of the metal hub of the road wheel and let it dry. Then, wrap the "sandwich structure" adhesive strip prepared in step (5) around the surface of the metal hub to a thickness of 30 mm.

[0046] (7) The metal wheel hub wrapped with the "sandwich structure" rubber strip obtained in step (6) is placed in a road wheel mold and vulcanized in steps at 15 MPa. The first step uses high-temperature vulcanization at 160°C for 4 minutes, and the second step uses low-temperature vulcanization at 145°C for 26 minutes to obtain a uniformly cured solid load-bearing tire of high modulus graphene oxide / natural rubber.

[0047] Example 2

[0048] An efficient preparation process for a uniformly cured solid load-bearing tire of high modulus graphene oxide / natural rubber is identical to that of Example 1, except that the amount of graphene oxide dispersion with a concentration of 10 mg / mL added in step (1) is 100 g.

[0049] Example 3

[0050] An efficient preparation process for a uniformly cured solid load-bearing tire of high modulus graphene oxide / natural rubber is identical to that of Example 1, except that the amount of sulfur added in steps (3) and (4) is 2.5 g.

[0051] The performance test results of Examples 1-3 are shown in Table 2.

[0052] Comparative Example 1

[0053] An efficient preparation process for a uniformly cured solid load-bearing tire of natural rubber is identical to that of Example 1, except that graphene oxide is not added.

[0054] Comparative Example 2

[0055] An efficient preparation process for a uniformly cured solid load-bearing tire of graphene oxide / natural rubber is identical to that of Example 1, except that no interfacial modifier is added.

[0056] Comparative Example 3

[0057] A high-efficiency preparation process for a graphene oxide / natural rubber solid load-bearing tire is the same as that of Example 1, except that step (4) is omitted and a rubber strip prepared from a high-modulus graphene oxide / carbon black / natural rubber mixed rubber sheet is used instead of the rubber strip made from the "sandwich structure" mixed rubber sheet in Example 1 to be laminated and wrapped around the wheel hub.

[0058] Comparative Example 4

[0059] An efficient preparation process for a graphene oxide / natural rubber solid load-bearing tire is the same as that in Example 1, except that a step-by-step vulcanization process is not used in step (7). Instead, a conventional vulcanization process is used with a vulcanization pressure of 15 MPa, a vulcanization temperature of 150° C., and a vulcanization time of 30 min.

[0060] The performance test results of Comparative Examples 1-4 are shown in Table 2.

[0061] Table 2 Performance test results of Examples 1 to 3 and Comparative Examples 1 to 4

[0062] As can be seen from Table 2, the solid road wheel rubber tire prepared by the present invention has the characteristics of high hardness, high modulus, low dynamic heat generation, and excellent mechanical properties. In addition, it can be seen from Table 2 that by using carbon black and GO as two reinforcing fillers in combination with in-situ interface modification to improve their compatibility with the NR matrix, thereby improving the dispersion of the reinforcing fillers in the rubber matrix, the hardness and mechanical properties of the rubber can be effectively improved. In addition, during the vulcanization stage of the load-bearing tire, the present invention uses a "sandwich structure" mixed rubber sheet to make a rubber strip that is laminated and wrapped around the wheel hub in conjunction with a step-by-step vulcanization process, which can enable the product to obtain the best uniformity of vulcanization degree, so that the molded solid rubber tire has excellent mechanical properties, thereby further improving the service life of the natural rubber road wheel solid tire.

[0063] The above description is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be included in the scope of protection of the claims.

Claims

1. An efficient preparation process for a high-modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire, characterized in that, The high modulus graphene oxide / natural rubber is made from the following raw materials in parts by mass: 100 parts of natural rubber, 40 - 120 parts of carbon black, 0.5 - 5 parts of graphene oxide, 1 - 20 parts of activator, 1 - 20 parts of softener, 1 - 10 parts of anti-aging agent, 1 - 10 parts of antioxidant, 1 - 20 parts of vulcanization accelerator, 1 - 20 parts of vulcanizing agent, and 1 - 20 parts of interfacial modifier; The preparation process includes the following steps: (1) Add deionized water to the graphene oxide slurry, and obtain a uniform aqueous dispersion of graphene oxide through ultrasonic dispersion; (2) Add the uniform aqueous dispersion of graphene oxide obtained in step (1) to natural latex, stir and mix well to obtain a uniformly dispersed mixed emulsion; add a flocculant to demulsify to obtain raw rubber, wash with water, remove water, and dry to obtain graphene oxide / natural rubber masterbatch; (3) Place the graphene oxide / natural rubber masterbatch obtained in step (2) in a mixer for mixing. Sequentially add carbon black, interfacial modifier, anti-aging agent, antioxidant, vulcanization accelerator, activator, and softener. Discharge the rubber compound after mixing for time A, cool to room temperature, then open mill the rubber compound on an open mill for time A, add a vulcanizing agent, mix evenly, and thin pass until there are no air bubbles in the rubber compound to obtain a high modulus graphene oxide / carbon black / natural rubber mixed rubber and press it into a film; (4) Place the graphene oxide / natural rubber masterbatch obtained in step (2) in a mixer for mixing. Sequentially add carbon black, interfacial modifier, anti-aging agent, antioxidant, vulcanization accelerator, activator, and softener. Discharge the rubber compound after mixing for time B, cool to room temperature, then open mill the rubber compound on an open mill for time B, add a vulcanizing agent, mix evenly, and thin pass until there are no air bubbles in the rubber compound to obtain a high viscosity graphene oxide / carbon black / natural rubber mixed rubber and press it into a film; (5) Place the high modulus graphene oxide / carbon black / natural rubber mixed rubber film obtained in step (3) between the upper and lower two high viscosity graphene oxide / carbon black / natural rubber mixed rubber films obtained in step (4) to form a "sandwich structure" mixed rubber, and after standing for a certain time, make a "sandwich structure" rubber strip with a width smaller than the width of the metal wheel hub; (6) Coat the surface of the metal wheel hub of the load wheel with an adhesive and let it dry, then wind the "sandwich structure" rubber strip prepared in step (5) around the surface of the metal wheel hub, and the winding thickness is the designed thickness of the rubber layer of the load wheel; (7) Place the metal wheel hub wrapped with the "sandwich structure" rubber strip obtained in step (6) in a load wheel mold and vulcanize step by step. The first step is to vulcanize at a high temperature for time C, and the second step is to vulcanize at a low temperature for time D to obtain a uniformly cured solid load tire of high modulus graphene oxide / natural rubber.

2. The high-efficiency preparation process of a high-modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire according to claim 1, characterized in that, The interfacial modifier is selected from at least one of Si69, Si75, Si75-ES, and Si264.

3. The high-efficiency preparation process of a high-modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire according to claim 1, characterized in that, The vulcanization accelerator is N-tert-butyl-2-benzothiazole sulfenamide, N-cyclohexyl-2-benzothiazole sulfenamide or N-(diethylenoxy)-2-benzothiazole sulfenamide; the antioxidant is 2,6-di-tert-butyl-4-methylphenol, 2,2,4-trimethyl-1,2-dihydroquinoline polymer or 2-mercaptobenzimidazole; the antioxidant agent is N-(1-methylisoamyl)-N'-phenyl-p-phenylenediamine, p-phenylenediamine or dilauryl thiodipropionate; the activator is zinc gluconate, zinc oxide or magnesium oxide; the softener is stearic acid, dibutyl titanate or dioctyl adipate; the vulcanizing agent is sulfur or sulfur monochloride.

4. The high-modulus graphene oxide / natural rubber and its efficient preparation process for uniformly cured solid load-bearing tires according to claim 1, characterized in that, In step (1), the power of the ultrasonic dispersion is 100-300 W, the time of the ultrasonic dispersion is 5-20 min, and the concentration of the obtained graphene oxide uniform aqueous dispersion is 2-6 mg / mL.

5. The high modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire efficient preparation process according to claim 1, characterized in that, In step (3), the mixing temperature in the internal mixer is 110-120 °C, and the mixing time A is 5-12 min; the mixing temperature of the open mill is 50-80 °C, and the mixing time A is 6-15 min; the mass ratio of the graphene oxide in step (1), the rubber solids in the natural rubber latex in step (2) to the carbon black, interface modifier, antioxidant, vulcanization accelerator, activator, softener and vulcanizing agent in step (3) is 0.5-5:100:40-120:1-20:1-10:1-10:1-20:1-20:1-20:1-20.

6. The high modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire high-efficiency preparation process according to claim 1, characterized in that, In step (4), the mixing temperature in the internal mixer is 110-120 °C, and the mixing time B is 5-12 min; the mixing temperature of the open mill is 50-80 °C, and the mixing time B is 15-25 min; the mass ratio of the graphene oxide in step (1), the rubber solids in the natural rubber latex in step (2) to the carbon black, interface modifier, antioxidant, vulcanization accelerator, activator, softener and vulcanizing agent in step (4) is 0.5-5:100:40-120:1-20:1-10:1-10:1-20:1-20:1-20:1-20.

7. The high modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire efficient preparation process according to claim 1, characterized in that In step (5), the thickness of the middle high-modulus mixing film of the "sandwich structure" mixing film is 3-6 mm, the thickness of the upper high-viscosity mixing film is 0.3-1 mm, and the thickness of the lower high-viscosity mixing film is 0.3-1 mm; the stopping glue time is 20-30 h.

8. The high-modulus graphene oxide / natural rubber uniformly cured solid load-bearing tire efficient preparation process according to claim 1, characterized in that, In step (6), the adhesive is a general adhesive, selected from at least one of Chemlok 6125, Chemlok 205 and Chemlok 6150.

9. The high modulus graphene oxide / natural rubber uniform curing solid load-bearing tire efficient preparation process according to claim 1, wherein, In step (7), the vulcanization pressure is 10-25 MPa, the first vulcanization temperature is 150-170 °C, the vulcanization time C is 2-6 min, the second vulcanization temperature is 140-150 °C, and the vulcanization time D is 10-30 min.

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