Preparation of long-life load-bearing tire made of natural rubber having undergone graphene / different-particle-size carbon black synergistic modification and vulcanization modification

Abstract

Preparation of a long-life load-bearing tire made of natural rubber having undergone graphene / different-particle-size carbon black synergistic modification and vulcanization modification. Carbon black having different particle sizes is subjected to surface modification to prepare a graphene oxide / different-particle-size carbon black uniform dispersion liquid, a rubber master batch is then prepared by using a water-phase synergetic coagulation-sedimentation process, and the long-life load-bearing tire made of natural rubber having undergone graphene / different-particle-size carbon black synergistic modification and vulcanization modification is eventually obtained. The dispersion of a reinforcing filler in a rubber matrix is improved by utilizing a method of compounding graphene and carbon black having different particle sizes, thereby slowing down the aging failure of the load-bearing tire while improving the hardness and mechanical properties of the rubber; moreover, the crosslinked network structure of the rubber is adjusted by regulating and controlling the ratio of a vulcanizing agent to an accelerant, thereby enabling the rubber to have better mechanical properties while improving the heat generation and hardness thereof, and therefore the service life of the load-bearing tire made of natural rubber is further prolonged.

Description

Preparation of natural rubber long-life load-bearing tires modified by synergistic vulcanization of graphene / carbon black with different particle sizes Technical Field

[0001] The invention belongs to the technical field of natural rubber and tires thereof, and particularly relates to the preparation of a natural rubber long-life load-bearing tire modified by synergistic vulcanization of graphene / carbon black of different particle sizes. Background Art

[0002] The unique strain-induced crystallization ability of natural rubber (NR) gives it excellent mechanical properties, wear resistance, high elasticity and other characteristics. As an extremely important key material, NR is currently widely used in load-bearing solid tires, tank road wheel tires and other fields. It is well known that during driving, load-bearing tires are subject to high-intensity impact and cyclic loads, so the requirements for the material performance of their molding are getting higher and higher. However, due to its low hardness, NR deforms greatly when subjected to external forces. On the one hand, it cannot bear heavy engineering equipment, and on the other hand, it is very easy to produce microcracks, leading to damage and failure, thereby reducing its service life. In addition, the hysteresis phenomenon caused by the unique viscoelasticity of NR causes it to convert mechanical energy into internal heat when subjected to dynamic stress, resulting in reduced performance of NR and eventual failure.

[0003] Graphene is a sp 2 New materials composed of hybrid-connected carbon atoms tightly packed into a single-layer two-dimensional honeycomb lattice structure exhibit excellent optical, electrical, and mechanical properties. They hold significant application prospects in materials, micro-nanofabrication, energy, biomedicine, and drug delivery, and are considered a revolutionary material of the future. Graphene oxide (GO) is a two-dimensional (2D) material with multiple oxygen-containing functional groups, obtained by oxidizing graphite through physical or chemical means. Graphene and its derivatives possess excellent mechanical strength, electrical conductivity, and thermal conductivity, making them widely used in rubber reinforcement and modification to improve the mechanical strength, toughness, and thermal conductivity of the resulting rubber composites.

[0004] Carbon black, a key reinforcing filler in NR, possesses a large number of functional groups on its surface and a branched aggregate microstructure, allowing it to entangle and adsorb with other fillers and rubber molecular chains. Therefore, adding carbon black to the rubber matrix can significantly improve hardness, wear resistance, and mechanical strength. Three factors influence the mechanical properties of rubber: particle size, surface structure, and surface activity. The particle size of carbon black is determined by its production process. Smaller particles increase the specific surface area, allowing for greater contact and adsorption with rubber molecular chains, resulting in better reinforcement. Structure indicates the degree of development of the branched structure within the carbon black aggregates; the more developed the branched structure, the higher the structure. Among these carbon black grades, N110 offers a small particle size and excellent reinforcement, N330 offers low heat generation and excellent wear resistance, N660 offers easy dispersion and low heat generation, and N765 offers a large particle size and excellent processing properties. Therefore, these grades are widely used for rubber reinforcement. However, while adding large amounts of a single carbon black reinforcing filler can effectively improve the hardness of rubber composites, it also causes them to generate significant heat when subjected to dynamic stress, which can easily cause the rubber product to age and fail. Furthermore, the addition of large amounts of a single reinforcing filler increases the cost of the composite material, further limiting the application of natural rubber composites in heavy-duty tires.

[0005] Vulcanization refers to the process of converting rubber from linear macromolecules to a three-dimensional network structure under certain temperature and pressure through the action of cross-linking agents such as vulcanizers and accelerators. The most traditional vulcanizing agent is sulfur. Currently, sulfur is still the most commonly used vulcanizing agent in the rubber products industry. In the sulfur vulcanization system, according to the proportion of sulfur and accelerator, it is divided into three types: conventional vulcanization system (CV), semi-effective vulcanization system (SEV) and effective vulcanization system (EV). Different types of vulcanization systems have different characteristics. Conventional vulcanization systems, also known as conventional vulcanization systems, use between 2 and 3 parts sulfur, along with appropriate amounts of accelerators and active agents. Semi-effective vulcanization systems use less sulfur than conventional systems, or a sulfur donor replaces some of the sulfur. Typically, the sulfur dosage ranges from 0.8 to 1.5 parts, with the combined sulfur donor and accelerator dosage exceeding 1 to 1.5 parts. Effective vulcanization systems use the least sulfur, typically 0.3 to 0.5 parts sulfur and 3 to 5 parts accelerator, or they may not use sulfur at all. Instead, they use a high-efficiency sulfur carrier as a vulcanizing agent in combination with an accelerator to enhance the activity of the vulcanization system. Rubber vulcanized with conventional vulcanization systems primarily exhibits polysulfide crosslinks, with minimal monosulfide and disulfide crosslinks. Rubber vulcanized with semi-effective vulcanization systems each comprises 50% polysulfide and 50% disulfide bonds. Rubber vulcanized with effective vulcanization systems primarily exhibits monosulfide or polysulfide bonds, accounting for over 90% of the total. The crosslink network (crosslink density and crosslink structure) of rubber composites is a key factor in their service performance and fatigue life. In recent years, many studies have used different vulcanization systems to manipulate the crosslink density and crosslink structure, thereby obtaining vulcanizates and products with different performance characteristics.

[0006] Summary of the Invention

[0007] To address the problem that the large-scale addition of a single reinforcing filler limits the application of natural rubber composites in the field of load-bearing tires, the present invention provides a method for preparing a long-life load-bearing tire by synergistically vulcanizing and modifying natural rubber using graphene / carbon black of different particle sizes. The present invention improves the life of natural rubber and the load-bearing tires formed therefrom in two ways. First, a modified natural rubber composite material for long-life load-bearing tires is prepared by compounding graphene and carbon black of different particle sizes to improve the dispersion of the reinforcing filler in the rubber matrix. This improves the hardness and mechanical properties of the rubber while also allowing the molded tire to have a lower compression heat value during movement, thereby slowing down the aging and failure of the load-bearing tire and extending its service life. Second, the cross-linked network structure of the rubber is adjusted by regulating the ratio of the vulcanizing agent to the accelerator. This improves the heat generation and hardness of the rubber while also providing it with better mechanical properties, thereby further improving the service life of the natural rubber load-bearing tire. Therefore, the present invention aims to provide a method for preparing a long-life load-bearing tire by synergistically vulcanizing and modifying natural rubber using graphene / carbon black of different particle sizes. First, natural rubber masterbatch modified with graphene oxide / carbon black of different particle sizes was prepared by aqueous phase synergistic coagulation process; then, natural rubber compound modified with graphene / carbon black of different particle sizes was prepared by mechanical blending method; finally, natural rubber long-life load-bearing tire modified with graphene / carbon black of different particle sizes by synergistic vulcanization was prepared by molding process.

[0008] The present invention is achieved through the following technical solution: a preparation method for a natural rubber long-life load-bearing tire modified by synergistic vulcanization of graphene / carbon black of different particle sizes, comprising the following steps:

[0009] (1) During the stirring process, water, sodium methylene dinaphthalene sulfonate, sodium alkyl naphthalene sulfonate, KOH and casein are sequentially added into a high-speed mixer, and after complete dissolution, quartz sand is added, and then carbon black of different particle sizes is added, and stirred at a certain speed for a certain time to obtain surface-treated carbon black dispersions of different particle sizes;

[0010] (2) adding deionized water to the graphene oxide aqueous dispersion, and then adding the surface-treated carbon black dispersion of different particle sizes obtained in step (1), and ultrasonicating at a certain power for a certain time to obtain a uniform aqueous dispersion of graphene oxide / carbon black of different particle sizes of a certain concentration;

[0011] (3) adding deionized water to the natural rubber emulsion and dispersing the mixture uniformly to obtain a natural rubber dispersion of a certain concentration, then adding the graphene oxide / carbon black aqueous dispersion prepared in step (2), mechanically stirring the mixture at a certain rate for a certain time to obtain a uniform mixed solution, then adding a flocculant of a certain concentration to break the emulsion to obtain raw rubber, washing the mixture with water, removing water, and drying the mixture to obtain a graphene oxide / carbon black modified natural rubber masterbatch of different particle sizes;

[0012] (4) placing the graphene oxide / different particle size carbon black modified natural rubber masterbatch obtained in step (3) in an internal mixer, mixing at a certain temperature, adding an anti-aging agent, an antioxidant and a vulcanization accelerator in sequence and continuing to mix, then adding an activator and a softener and continuing to mix, discharging the rubber after uniform mixing and cooling to room temperature; mixing the obtained rubber material cooled to room temperature on a double roller of an open mixer at a certain temperature for a certain time, adding a vulcanizing agent sulfur, mixing evenly, and thinning until there are no bubbles in the rubber material, stopping mixing for a certain time, and obtaining a natural rubber compound modified with graphene / different particle size carbon black;

[0013] (5) placing the rubber mixture obtained in step (4) into a mold, and vulcanizing it at a certain pressure and temperature for a certain time to obtain a graphene / carbon black of different particle sizes synergistically vulcanized modified natural rubber long-life load-bearing tire.

[0014] As a further improvement of the technical solution of the present invention, in step (1), the mass ratio of water, sodium methylene dinaphthalene sulfonate, sodium alkylnaphthalene sulfonate, KOH, casein, quartz sand and carbon black of different particle sizes is 720:1:0.5:1.5:3:150:80.

[0015] As a further improvement of the technical solution of the present invention, the carbon black of different particle sizes includes N330 carbon black, carbon black N110, carbon black N660, and carbon black N765 in a mass ratio of 3:0-1:0-1:0-1, and carbon black N110, carbon black N660, and carbon black N765 are not 0 at the same time.

[0016] As a further improvement of the technical solution of the present invention, in step (1), after adding carbon black of different particle sizes, the stirring speed is 400 to 6000 r / min and the stirring is carried out for 30 to 50 minutes.

[0017] As a further improvement of the technical solution of the present invention, in step (2), the concentration of the graphene oxide dispersion obtained after adding deionized water is 2 to 6 mg / mL; after adding carbon black dispersions of different particle sizes, the ultrasonic power is 100 to 300 W, and the ultrasonic time is 15 to 20 minutes.

[0018] As a further improvement of the technical solution of the present invention, in step (3), the concentration of the natural latex obtained after adding deionized water is 10 to 30 wt%.

[0019] As a further improvement of the technical solution of the present invention, in step (3), after adding the graphene oxide / carbon black aqueous dispersion of different particle sizes, the speed of mechanical stirring is 400-700 r / min, and the stirring time is 10-30 min.

[0020] As a further improvement of the technical solution of the present invention, in step (3), the graphene oxide content in the graphene oxide / different particle size carbon black modified natural rubber masterbatch is 0.28 wt.%, and the carbon black content is 44.3 wt.%.

[0021] As a further improvement of the technical solution of the present invention, in step (4), the mass ratio of the natural rubber, antioxidant, antioxidant, vulcanization accelerator, activator, softener and vulcanizer is 100:1:1:1:5:2:3; the mixing temperature in the internal mixer is 110-120°C; the mixing temperature on the open mixer is 50-80°C, the double-roll speed is 12-20r / min, and the mixing time is 6-15min; and the rubber stop time is 20-30h.

[0022] As a further improvement of the technical solution of the present invention, in step (5), the vulcanization pressure is 10-20 MPa, the vulcanization temperature is 140-160° C., and the vulcanization time is 5-20 min.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention utilizes a method of compounding graphene and carbon black of different particle sizes to prepare a modified natural rubber composite material for long-life load-bearing tires, so as to improve the dispersion of reinforcing fillers in the rubber matrix. While improving the hardness and mechanical properties of the rubber, the molded rubber composite material has a lower compression heat value during movement, thereby slowing down the aging and failure of the load-bearing tire, extending its service life, and meeting the application requirements of the load-bearing tire. This provides a new idea for the application of graphene / carbon black of different particle sizes synergistically vulcanized modified natural rubber composite materials in load-bearing tires.

[0025] (2) The present invention adjusts the cross-linked network structure of the rubber by regulating the ratio of the vulcanizer to the accelerator, thereby improving the heat generation and hardness of the rubber and making it have better mechanical properties, thereby further improving the service life of the natural rubber load-bearing tire.

[0026] (3) Compared to other tire preparation processes, the present invention uses an efficient, industrially convenient aqueous phase synergistic coagulation process to prepare a well-dispersed graphene oxide / carbon black of varying particle sizes modified natural rubber masterbatch, further prepares a graphene oxide / carbon black of varying particle sizes synergistically modified natural rubber compound by mechanical blending, and finally prepares a graphene / carbon black of varying particle sizes synergistically vulcanized modified natural rubber long-life load-bearing tire by molding. Each of the above steps can be prepared using conventional processes, making it easy to industrialize.

[0027] (4) The materials involved in the preparation of graphene / carbon black of different particle sizes synergistically vulcanized modified natural rubber in the present invention are all green, environmentally friendly and inexpensive; in addition, the process can be produced continuously, the instruments and equipment are easy to operate, and industrial production can be easily realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] FIG1 is a scanning electron microscope photograph of the reinforcing fillers carbon black N110, N330, N660, and N765 used in Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.

[0031] FIG2 shows the particle size and distribution of the reinforcing fillers carbon black N110, N330, N660, and N765 used in Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention, as measured by a Zeta potential particle size analyzer.

[0032] FIG3 is a graph showing (a) thermogravimetric and (b) Raman spectra of the reinforcing filler carbon black before and after modification in Example 3 of the present invention.

[0033] FIG4 shows the crosslinking density of natural rubber modified by synergistic vulcanization of graphene / carbon black of different particle sizes prepared in Example 3 of the present invention and Comparative Examples 3 to 4. DETAILED DESCRIPTION

[0034] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0036] The present invention provides a specific embodiment of preparing a natural rubber long-life load-bearing tire synergistically vulcanized and modified by graphene / carbon black of different particle sizes, comprising the following steps:

[0037] (1) During the stirring process, water, sodium methylene dinaphthalene sulfonate, sodium alkyl naphthalene sulfonate, KOH and casein are sequentially added into a high-speed mixer, and after complete dissolution, quartz sand is added, and then carbon black of different particle sizes is added, and stirred at a certain speed for a certain time to obtain surface-treated carbon black dispersions of different particle sizes;

[0038] (2) adding deionized water to the graphene oxide aqueous dispersion, and then adding the surface-treated carbon black dispersion of different particle sizes obtained in step (1), and ultrasonicating at a certain power for a certain time to obtain a uniform aqueous dispersion of graphene oxide / carbon black of different particle sizes of a certain concentration;

[0039] (3) adding deionized water to the natural rubber emulsion and dispersing the mixture uniformly to obtain a natural rubber dispersion of a certain concentration, then adding the graphene oxide / carbon black aqueous dispersion prepared in step (2), mechanically stirring the mixture at a certain rate for a certain time to obtain a uniform mixed solution, then adding a flocculant of a certain concentration to break the emulsion to obtain raw rubber, washing the mixture with water, removing water, and drying the mixture to obtain a graphene oxide / carbon black modified natural rubber masterbatch of different particle sizes;

[0040] (4) placing the graphene oxide / different particle size carbon black modified natural rubber masterbatch obtained in step (3) in an internal mixer, mixing at a certain temperature, adding an anti-aging agent, an antioxidant and a vulcanization accelerator in sequence and continuing to mix, then adding an activator and a softener and continuing to mix, discharging the rubber after uniform mixing and cooling to room temperature; mixing the obtained rubber material cooled to room temperature on a double roller of an open mixer at a certain temperature for a certain time, adding a vulcanizing agent sulfur, mixing evenly, and thinning until there are no bubbles in the rubber material, stopping mixing for a certain time, and obtaining a natural rubber compound modified with graphene / different particle size carbon black;

[0041] (5) placing the rubber mixture obtained in step (4) into a mold, and vulcanizing it at a certain pressure and temperature for a certain time to obtain a graphene / carbon black of different particle sizes synergistically vulcanized modified natural rubber long-life load-bearing tire.

[0042] In one embodiment provided by the present invention, in step (1), the mass ratio of water, sodium methylene dinaphthalene sulfonate, sodium alkylnaphthalene sulfonate, KOH, casein, quartz sand, and carbon black of different particle sizes is 720:1:0.5:1.5:3:150:80. In the present invention, the carbon black of different particle sizes includes carbon black of at least two particle sizes.

[0043] In another embodiment provided by the present invention, the carbon black of different particle sizes includes N330 carbon black, N110 carbon black, N660 carbon black, and N765 carbon black in a mass ratio of 3:0-1:0-1:0-1, and the mass ratios of N110 carbon black, N660 carbon black, and N765 carbon black are not all zero. In the present invention, the carbon black of different particle sizes is mainly composed of N330 carbon black and is compounded with N110 carbon black, N660 carbon black, and N765 carbon black. The carbon black of different particle sizes is a mixture of N330 carbon black and at least one of N110 carbon black, N660 carbon black, and N765 carbon black.

[0044] In one embodiment provided by the present invention, in step (1), after adding carbon black of different particle sizes, the stirring speed is 400 to 6000 r / min and the stirring is carried out for 30 to 50 minutes.

[0045] In another embodiment provided by the present invention, in step (2), the concentration of the graphene oxide dispersion obtained after adding deionized water is 2 to 6 mg / mL; after adding carbon black dispersions of different particle sizes, the ultrasonic power is 100 to 300 W, and the ultrasonic time is 15 to 20 min.

[0046] In one embodiment provided by the present invention, in step (3), the concentration of the natural latex obtained after adding deionized water is 10 to 30 wt%.

[0047] In another embodiment provided by the present invention, in step (3), after adding the graphene oxide / carbon black aqueous dispersion of different particle sizes, the mechanical stirring speed is 400-700 rpm and the stirring time is 10-30 min. The concentration of the flocculant calcium chloride in this embodiment is 5-10 wt%.

[0048] In one embodiment provided by the present invention, in step (3), the graphene oxide content in the graphene oxide / different particle size carbon black modified natural rubber masterbatch is 0.28 wt.%, and the carbon black content is 44.3 wt.%.

[0049] In another embodiment provided by the present invention, in step (4), the mass ratio of the natural rubber, antioxidant, antioxidant, vulcanization accelerator, activator, softener, and vulcanizer is 100:1:1:1:5:2:3; the mixing temperature in the internal mixer is 110-120°C, and the mixing time is 5 minutes; the mixing time after adding the antioxidant, antioxidant, and vulcanization accelerator is continued for 5 minutes; the mixing time after adding the activator and softener is continued for 5 minutes. The mixing temperature on the open mixer is 50-80°C, the double-roll speed is 12-20 r / min, the mixing time is 6-15 minutes, and the rubber stop time is 20-30 hours.

[0050] In one embodiment provided by the present invention, in step (5), the vulcanization pressure is 10-20 MPa, the vulcanization temperature is 140-160° C., and the vulcanization time is 5-20 min.

[0051] The specific embodiments of the present invention are described in detail below.

[0052] Example 1:

[0053] A method for preparing a natural rubber long-life load-bearing tire modified by synergistic vulcanization of graphene / carbon black of different particle sizes comprises the following steps:

[0054] (1) 720 g of deionized water was added to a high-speed mixer. During the stirring process, 1 g of sodium methylene dinaphthalene sulfonate, 0.5 g of sodium alkylnaphthalene sulfonate, 1.5 g of KOH, and 3 g of casein were added in sequence. After complete dissolution, 150 g of quartz sand was added. Then, 60 g of carbon black N330 and 20 g of carbon black N110 were added, respectively. The mixture was stirred at 4000 r / min for 30 min to obtain surface-treated carbon black dispersions of different particle sizes.

[0055] (2) Weigh 50 g of a 10 mg / ml graphene oxide (GO) dispersion, add it to deionized water to prepare a 2 mg / mL graphene oxide dispersion, then add the surface-treated carbon black dispersion of different particle sizes obtained in step (1), and ultrasonically disperse it at a power of 100 W for 10 min to obtain a 76.6 mg / mL graphene oxide / carbon black dispersion of different particle sizes;

[0056] (3) adding deionized water to 166.7 g of a natural rubber latex solution having a solid content of 60 wt.% to dilute it to a natural rubber latex solution having a solid content of 30 wt.%; then adding the graphene oxide / carbon black dispersion prepared in step (2), mechanically stirring at a speed of 400 r / min for 10 min, and fully mixing to obtain a uniformly dispersed mixed emulsion; adding 120 g of a 5 wt.% CaCl2 solution to the mixed solution to demulsify the raw rubber, washing, dehydrating, and drying to obtain a graphene oxide / carbon black modified natural rubber masterbatch; the graphene oxide content in the graphene oxide / carbon black modified natural rubber masterbatch is 0.28 wt.%, and the carbon black content is 44.3 wt.%;

[0057] (4) The graphene oxide / carbon black modified natural rubber masterbatch obtained in step (3) was placed in an internal mixer and mixed at 110° C. for 5 min. 1 g of antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline polymer (RD), 1 g of antioxidant N-isopropyl-N'-phenyl-p-phenylenediamine (4010NA), and 1 g of vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfenamide (CZ) were added in batches and mixed for 5 min. min; then, 5 g of activator ZnO and 2 g of softener stearic acid (SA) were added and the mixing was continued for 5 min. After the mixture was uniformly mixed, the rubber material was discharged and cooled to room temperature; the obtained rubber material cooled to room temperature was passed through a double roller of an open mill and mixed at 50° C. for 3 min. Then, 3 g of vulcanizing agent sulfur (S) was added and the mixing was continued for 3 min. After uniform mixing, the mixture was thinly passed until there were no bubbles in the rubber material. The mixing was stopped for 20 h to obtain a natural rubber compound synergistically modified with graphene / carbon black of different particle sizes;

[0058] (5) placing the rubber mixture obtained in step (4) into a mold and vulcanizing it at 10 MPa and 140° C. for 20 min to obtain a natural rubber long-life load-bearing tire synergistically vulcanized and modified with graphene / carbon black of different particle sizes.

[0059] Example 2:

[0060] A method for preparing a natural rubber long-life load-bearing tire modified by synergistic vulcanization of graphene / carbon black of different particle sizes comprises the following steps:

[0061] (1) 720 g of deionized water was added to a high-speed mixer. During the stirring process, 1 g of sodium methylene dinaphthalene sulfonate, 0.5 g of sodium alkylnaphthalene sulfonate, 1.5 g of KOH, and 3 g of casein were added in sequence. After complete dissolution, 150 g of quartz sand was added. Then, 60 g of carbon black N330 and 20 g of carbon black N660 were added, respectively. The mixture was stirred at 5000 r / min for 40 min to obtain surface-treated carbon black dispersions of different particle sizes.

[0062] (2) Weigh 50 g of a 10 mg / ml graphene oxide (GO) dispersion, add deionized water to prepare a 4 mg / mL graphene oxide dispersion, then add the surface-treated carbon black dispersion of different particle sizes obtained in step (1), and ultrasonically disperse at a power of 200 W for 15 min to obtain an 86.5 mg / mL graphene oxide / carbon black dispersion of different particle sizes;

[0063] (3) adding deionized water to 166.7 g of a natural rubber latex solution having a solid content of 60 wt.% to dilute it to a natural rubber latex solution having a solid content of 40 wt.%; then adding the deionized water to the graphene oxide / carbon black dispersion of different particle sizes prepared in step (2), mechanically stirring at a speed of 600 r / min for 20 min, and fully mixing to obtain a uniformly dispersed mixed emulsion; adding 80 g of a 7.5 wt.% CaCl2 solution to the mixed solution to demulsify the raw rubber, washing, dehydrating, and drying to obtain a graphene oxide / carbon black of different particle sizes modified natural rubber masterbatch; the graphene oxide content in the graphene oxide / carbon black modified natural rubber masterbatch is 0.28 wt.%, and the carbon black content is 44.3 wt.%;

[0064] (4) The graphene oxide / carbon black of different particle sizes modified natural rubber masterbatch obtained in step (3) is placed in an internal mixer and internally mixed at 115° C. for 5 min. 1 g of antioxidant RD, 1 g of antioxidant 4010NA and 1 g of vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfonamide (CZ) are added in batches and the mixing is continued for 5 min. Then, 5 g of activator ZnO and 2 g of softener SA are added and the mixing is continued for 5 min. After uniform mixing, the rubber material is discharged and cooled to room temperature. The obtained rubber material cooled to room temperature is passed through the double rollers of an open mixer and milled at 60° C. for 5 min. Then, 3 g of vulcanizing agent sulfur (S) is added and the mixing is continued for 5 min. After uniform mixing, the rubber material is thinly passed until there are no bubbles in the rubber material. The rubber material is stopped for 25 h to obtain a natural rubber compound modified with graphene / carbon black of different particle sizes.

[0065] (5) placing the rubber mixture obtained in step (4) into a mold and vulcanizing it at 15 MPa and 150° C. for 10 min to obtain a natural rubber long-life load-bearing tire synergistically vulcanized and modified with graphene / carbon black of different particle sizes.

[0066] Example 3:

[0067] A method for preparing a natural rubber long-life load-bearing tire modified by synergistic vulcanization of graphene / carbon black of different particle sizes comprises the following steps:

[0068] (1) 720 g of deionized water was added to a high-speed mixer. During the stirring process, 1 g of sodium methylene dinaphthalene sulfonate, 0.5 g of sodium alkylnaphthalene sulfonate, 1.5 g of KOH, and 3 g of casein were added in sequence. After complete dissolution, 150 g of quartz sand was added. Then, 60 g of carbon black N330 and 20 g of carbon black N765 were added, respectively. The mixture was stirred at 6000 r / min for 50 min to obtain surface-treated carbon black dispersions of different particle sizes.

[0069] (2) Weigh 50 g of a 10 mg / ml graphene oxide (GO) dispersion and add deionized water to prepare a 6 mg / mL graphene oxide dispersion; then add the surface-treated carbon black dispersion of different particle sizes obtained in step (1), and ultrasonically disperse at a power of 300 W for 20 min to obtain a 91.1 mg / mL graphene oxide / carbon black dispersion of different particle sizes;

[0070] (3) adding deionized water to 166.7 g of a natural rubber latex solution having a solid content of 60 wt.% to dilute it to a natural rubber latex solution having a solid content of 50 wt.%; then adding the deionized water to the graphene oxide / carbon black dispersion of different particle sizes prepared in step (2), mechanically stirring at a speed of 700 r / min for 30 min, and fully stirring and mixing to obtain a uniformly dispersed mixed emulsion; adding 60 g of a 10 wt.% CaCl2 solution to the mixed solution to demulsify the raw rubber, washing, dehydrating, and drying to obtain a natural rubber masterbatch synergistically modified with graphene oxide / carbon black of different particle sizes; the graphene oxide content in the graphene oxide / carbon black modified natural rubber masterbatch is 0.28 wt.%, and the carbon black content is 44.3 wt.%;

[0071] (4) The natural rubber masterbatch modified with graphene oxide / carbon black of different particle sizes obtained in step (3) is placed in an internal mixer and mixed at 120° C. for 5 min. 1 g of antioxidant RD, 1 g of antioxidant 4010NA and 1 g of vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfonamide (CZ) are added in batches and mixed for 5 min. 5 g of activator ZnO and 2 g of softener SA are added and mixed for 5 min. After mixing evenly, the rubber is discharged and cooled to room temperature. The rubber obtained by cooling to room temperature is passed through the double rollers of an open mixer and mixed at 80° C. for 7.5 min. 3 g of vulcanizing agent sulfur (S) is added and mixed for 7.5 min. After mixing evenly, the rubber is thinly passed until there are no bubbles in the rubber. The rubber is stopped for 30 h to obtain a natural rubber compound modified with graphene / carbon black of different particle sizes.

[0072] (5) placing the rubber mixture obtained in step (4) into a mold and vulcanizing it at 20 MPa and 160° C. for 5 min to obtain a natural rubber long-life load-bearing tire synergistically vulcanized and modified with graphene / carbon black of different particle sizes.

[0073] Comparative Example 1:

[0074] A method for preparing a natural rubber load-bearing tire modified by synergistic vulcanization of graphene / N330 carbon black comprises the following steps:

[0075] (1) 720 g of deionized water was added to a high-speed mixer, and 1 g of sodium methylene dinaphthalene sulfonate, 0.5 g of sodium alkylnaphthalene sulfonate, 1.5 g of KOH, and 3 g of casein were added in sequence during the stirring process. After complete dissolution, 150 g of quartz sand was added, and then 80 g of carbon black N330 was added. The mixture was stirred at 6000 r / min for 50 min to obtain a surface-treated N330 carbon black dispersion. The mixture was stirred at 6000 r / min for 50 min to obtain surface-treated carbon black dispersions of different particle sizes.

[0076] (2) Weigh 50 g of a 10 mg / ml graphene oxide (GO) dispersion and add deionized water to prepare a 6 mg / mL graphene oxide dispersion; then add the surface-treated N330 carbon black dispersion obtained in step (1), and ultrasonically disperse at 300 W for 20 min to obtain a 91.1 mg / mL graphene oxide / N330 carbon black aqueous uniform dispersion;

[0077] (3) adding deionized water to 166.7 g of a natural rubber latex solution having a solid content of 60 wt.% to dilute it to a natural rubber latex solution having a solid content of 50 wt.%; then adding the deionized water to the graphene oxide / N330 carbon black dispersion prepared in step (2), mechanically stirring at a speed of 700 r / min for 30 min, and fully stirring and mixing to obtain a uniformly dispersed mixed emulsion; adding 60 g of a 10 wt.% CaCl2 solution to the mixed solution to demulsify the raw rubber, washing with water, dehydrating, and drying to obtain a graphene oxide / N330 carbon black modified natural rubber masterbatch;

[0078] (4) The graphene oxide / N330 carbon black modified natural rubber masterbatch obtained in step (3) is placed in an internal mixer and internally mixed at 120° C. for 5 min. 1 g of antioxidant RD, 1 g of antioxidant 4010NA and 1 g of vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfonamide (CZ) are added in batches and the mixing is continued for 5 min. Then, 5 g of activator ZnO and 2 g of softener SA are added and the mixing is continued for 5 min. After uniform mixing, the rubber material is discharged and cooled to room temperature. The obtained rubber material cooled to room temperature is passed through the double rollers of an open mixer and milled at 80° C. for 7.5 min. Then, 3 g of vulcanizing agent sulfur (S) is added and the mixing is continued for 7.5 min. After uniform mixing, the rubber material is thinly passed until there are no bubbles in the rubber material. The rubber material is stopped for 30 h to obtain a natural rubber compound modified with graphene / N330 carbon black.

[0079] (5) placing the rubber mixture obtained in step (4) into a mold and vulcanizing it at 20 MPa and 160° C. for 5 min to obtain a natural rubber load-bearing tire modified by synergistic vulcanization of graphene / N330 carbon black.

[0080] Comparative Example 2:

[0081] A method for preparing a natural rubber load-bearing tire modified with graphene / carbon black of different particle sizes comprises the following steps:

[0082] (1) Weigh 50 g of 10 mg / ml graphene oxide (GO) dispersion, add deionized water, and ultrasonically disperse at 300 W for 20 min to obtain 6 mg / mL graphene oxide dispersion;

[0083] (2) adding deionized water to 166.7 g of a natural rubber latex solution having a solid content of 60 wt.% to dilute it to a natural rubber latex solution having a solid content of 50 wt.%; then adding the deionized water to the graphene oxide dispersion prepared in step (1), mechanically stirring at a speed of 700 r / min for 30 min, and fully stirring and mixing to obtain a uniformly dispersed mixed emulsion; adding 60 g of a 10 wt.% CaCl2 solution to the mixed solution to demulsify the raw rubber, washing with water, dehydrating, and drying to obtain a graphene oxide natural rubber masterbatch;

[0084] (3) The graphene oxide modified natural rubber masterbatch obtained in step (2) is placed in an internal mixer and internally mixed at 120° C. for 5 min, and 1 g of antioxidant RD, 1 g of antioxidant 4010NA and 1 g of vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfonamide (CZ) are added in batches and then the internal mixing is continued for 5 min; then 5 g of activator ZnO, 2 g of softener SA, and 60 g of carbon black N330 are added and internal mixing is continued for 2.5 min, followed by adding 20 g of carbon black N765 and internal mixing for 2.5 min. After uniform mixing, the rubber material is discharged and cooled to room temperature; the obtained rubber material cooled to room temperature is passed through the double rollers of an open mixer and internal mixing is continued at 80° C. for 7.5 min, and then 3 g of vulcanizing agent sulfur (S) is added and internal mixing is continued for 7.5 min. After uniform mixing, the rubber material is thinly passed until there is no bubble in the rubber material, and the rubber material is stopped for 30 h to obtain a graphene / natural rubber compound modified with carbon black of different particle sizes;

[0085] (4) placing the rubber mixture obtained in step (3) into a mold and vulcanizing it at 20 MPa and 160° C. for 5 min to obtain a natural rubber load-bearing tire modified with graphene / carbon black of different particle sizes.

[0086] Comparative Example 3:

[0087] A method for preparing a natural rubber load-bearing tire synergistically modified with graphene / carbon black of different particle sizes comprises the following steps:

[0088] (1) 720 g of deionized water was added to a high-speed mixer. During the stirring process, 1 g of sodium methylene dinaphthalene sulfonate, 0.5 g of sodium alkylnaphthalene sulfonate, 1.5 g of KOH, and 3 g of casein were added in sequence. After complete dissolution, 150 g of quartz sand was added. Then, 60 g of carbon black N330 and 20 g of carbon black N765 were added, respectively. The mixture was stirred at 6000 r / min for 50 min to obtain surface-treated carbon black dispersions of different particle sizes.

[0089] (2) Weigh 50 g of a 10 mg / ml graphene oxide (GO) dispersion and add deionized water to prepare a 6 mg / mL graphene oxide dispersion; then add the surface-treated carbon black dispersion of different particle sizes obtained in step (1), and ultrasonically disperse at a power of 300 W for 20 min to obtain a 91.1 mg / mL graphene oxide / carbon black dispersion of different particle sizes;

[0090] (3) adding deionized water to 166.7 g of a natural rubber latex solution having a solid content of 60 wt.% to dilute it to a natural rubber latex solution having a solid content of 50 wt.%; then adding it to the graphene oxide / carbon black dispersion prepared in step (2), mechanically stirring at a speed of 700 r / min for 30 min, and fully stirring and mixing to obtain a uniformly dispersed mixed emulsion; adding 60 g of a 10 wt.% CaCl2 solution to the mixed solution to demulsify the raw rubber, washing, dehydrating, and drying to obtain a graphene oxide / carbon black of different particle sizes synergistically modified natural rubber masterbatch;

[0091] (4) The graphene oxide / carbon black of different particle sizes synergistically modified natural rubber masterbatch obtained in step (3) is placed in an internal mixer and mixed at 120° C. for 5 min. 1 g of antioxidant RD, 1 g of antioxidant 4010NA and 2 g of vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfonamide (CZ) are added in batches and mixed for 5 min. 5 g of activator ZnO and 2 g of softener SA are added and mixed for 5 min. After mixing evenly, the rubber is discharged and cooled to room temperature. The rubber obtained by cooling to room temperature is passed through the double rollers of an open mixer and mixed at 80° C. for 7.5 min. 2 g of vulcanizing agent sulfur (S) is added and mixed for 7.5 min. After mixing evenly, the rubber is thinly passed until there are no bubbles in the rubber. The rubber is stopped for 30 h to obtain a natural rubber compound modified with graphene / carbon black of different particle sizes.

[0092] (5) placing the rubber mixture obtained in step (4) into a mold and vulcanizing it at 20 MPa and 160° C. for 5 min to obtain a natural rubber load-bearing tire synergistically modified with graphene / carbon black of different particle sizes.

[0093] Comparative Example 4:

[0094] A method for preparing a natural rubber long-life load-bearing tire synergistically modified with graphene / carbon black of different particle sizes comprises the following steps:

[0095] (1) 720 g of deionized water was added to a high-speed mixer. During the stirring process, 1 g of sodium methylene dinaphthalene sulfonate, 0.5 g of sodium alkylnaphthalene sulfonate, 1.5 g of KOH, and 3 g of casein were added in sequence. After complete dissolution, 150 g of quartz sand was added. Then, 60 g of carbon black N330 and 20 g of carbon black N765 were added, respectively. The mixture was stirred at 6000 r / min for 50 min to obtain surface-treated carbon black dispersions of different particle sizes.

[0096] (2) Weigh 50 g of a 10 mg / ml graphene oxide (GO) dispersion and add deionized water to prepare a 6 mg / mL graphene oxide dispersion; then add the surface-treated carbon black dispersion of different particle sizes obtained in step (1), and ultrasonically disperse at a power of 300 W for 20 min to obtain a 91.1 mg / mL graphene oxide / carbon black dispersion of different particle sizes;

[0097] (3) adding deionized water to 166.7 g of a natural rubber latex solution having a solid content of 60 wt.% to dilute it to a natural rubber latex solution having a solid content of 50 wt.%; then adding the graphene oxide / carbon black dispersion prepared in step (2), mechanically stirring at a speed of 700 r / min for 30 min, and fully stirring and mixing to obtain a uniformly dispersed mixed emulsion; adding 60 g of a 10 wt.% CaCl2 solution to the mixed solution to demulsify the raw rubber, washing with water, removing water, and drying to obtain a graphene oxide / carbon black modified natural rubber masterbatch of different particle sizes.

[0098] (4) The graphene oxide / different particle size carbon black modified natural rubber masterbatch obtained in step (3) is placed in an internal mixer, and is internally mixed at 120° C. for 5 min. 1 g of antioxidant RD, 1 g of antioxidant 4010NA and 3 g of vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfonamide (CZ) are added in batches and the mixing is continued for 5 min. Then, 5 g of activator ZnO and 2 g of softener SA are added and the mixing is continued for 5 min. After uniform mixing, the rubber material is discharged and cooled to room temperature. The obtained rubber material cooled to room temperature is passed through the double rollers of an open mixer and is mixed at 80° C. for 7.5 min. 1 g of vulcanizing agent sulfur (S) is added and the mixing is continued for 7.5 min. After uniform mixing, the rubber material is thinly passed until there are no bubbles in the rubber material. The rubber material is stopped for 30 h to obtain a graphene / different particle size carbon black synergistically modified natural rubber compound.

[0099] (5) placing the rubber mixture obtained in step (4) into a mold and vulcanizing it at 20 MPa and 160° C. for 5 min to obtain a natural rubber load-bearing tire synergistically modified with graphene / carbon black of different particle sizes.

[0100] Table 1 is the formula table of Examples 1 to 3 and Comparative Examples 1 to 4. The performance test results of Examples 1 to 3 and Comparative Examples 1 to 2 are shown in Table 2. The performance test results of Example 3 and Comparative Examples 3 to 4 are shown in Table 3.

[0101] Table 1 Formulations of Examples 1 to 3 and Comparative Examples 1 to 4

[0102] Samples from the tires prepared in Examples 1-3 and Comparative Examples 1-4 were taken and tested for hardness, heat buildup, mechanical properties, wear, and permanent deformation of the modified NR composites. Mechanical properties were tested according to ISO 37-2005, with a tensile rate of 500 mm / min and a tear rate of 500 mm / min. Heat buildup was tested according to ISO 4666; hardness was tested according to ISO 7619-1:2004; and wear and permanent deformation properties were tested according to GB / T 9867-2008.

[0103] Table 2 Properties of the natural rubber composites modified by synergistic vulcanization of graphene / carbon black of different particle sizes of the present invention

[0104] As can be seen from Table 2, the graphene / carbon black of different particle sizes synergistically vulcanized natural rubber composite material prepared by the present invention through an aqueous synergistic coagulation process exhibits high hardness, low heat generation, and excellent mechanical properties. Furthermore, Table 2 also shows that the graphene / carbon black of different particle sizes synergistically vulcanized natural rubber composite material prepared by the present invention through compounding carbon blacks of different particle sizes meets the engineering application requirements of load-bearing tires, while significantly reducing heat generation and significantly outperforming the mechanical properties of graphene oxide / carbon black-modified natural rubber composite material prepared from a single carbon black type. This fully demonstrates the advantages of the present method of compounding reinforcing filler carbon blacks of different particle sizes in significantly increasing the hardness of the prepared rubber composite material and reducing its heat generation.

[0105] Table 3 Properties of the natural rubber composites modified by synergistic vulcanization of graphene / reinforced fillers of different particle sizes of the present invention

[0106] As can be seen from Table 3, the present invention can effectively adjust the cross-linked network structure of the rubber by regulating the ratio of the vulcanizing agent to the vulcanization accelerator, thereby preparing a natural rubber and a long-life load-bearing tire synergistically vulcanized and modified with graphene / carbon black of different particle sizes. On the basis of improving the heat generation and hardness of the rubber product, it also has excellent mechanical properties, thereby further extending the service life of the molded load-bearing tire.

[0107] As shown in Figure 1, in terms of size, Figure 1(a) shows that carbon black N110 has the smallest particle size, and its monomer exhibits an elliptical spherical structure. When the carbon black model changes from N110 to N765, the particle size continues to increase. Figure 1(d) shows that compared to the other carbon black models, carbon black N765 has the largest particle size and its monomer has changed from the elliptical spherical structure of carbon black N110 to a flat circular structure. This structure greatly reduces its surface area, and therefore, when used as a reinforcing filler for NR, it will reduce the contact area with the rubber molecular chain. In terms of aggregate structure, carbon black monomers aggregate and stack to form branched agglomerates. When the carbon black model changes from N110 to N765, the carbon black particle size gradually increases, and the branched structure of carbon black changes from short and dense to long and sparse.

[0108] As shown in Figure 2(a), the average particle size of carbon black N110 is 253.8nm. As shown in Figure 2(b), the particle size of N110 is mainly distributed around 250nm, with a few agglomerates distributed around 2500nm. This indicates that the particle size of N110 carbon black is small and its branched structure is short, which can improve its dispersion in rubber composites. As shown in Figure 2(a), the average particle size of carbon black N330 is 275.6nm. As shown in Figure 2(b), its particle size is mostly distributed around 300nm. As shown in Figure 2(a), the average particle size of N660 is 324.8nm. As shown in Figure 2(b), its particle size is distributed in two parts, around 186nm and 557nm respectively. As shown in Figure 2(a), the average particle size of carbon black type N765 is the highest, at 477.2 nm. As shown in Figure 2(b), most of its particle sizes are distributed around 526 nm, and the rest are around 4600 nm. Compared with other types of carbon black, the particle size distribution of N765 is wider, indicating that most of its monomer particles are agglomerated and stacked together, forming a longer branched structure.

[0109] As shown in the Raman spectrum of Figure 3(a), compared with the unmodified carbon black, the I D / I G The value increased from 0.65 to 0.90, I D / I GThe increase means that the surface of carbon black is wrapped and adsorbed by the modifier sodium methylene dinaphthalene sulfonate, and the carbon structure of the introduced sodium methylene dinaphthalene sulfonate is different from that of carbon black, which reduces the degree of order of carbon black and further increases the disordered carbon. Figure 3(b) is the thermogravimetric curve of unmodified carbon black and modified carbon black. It can be seen that the mass loss of unmodified carbon black is small, and it always maintains a slow weight loss throughout the heating stage. The reason for the weight loss of modified carbon black is that at low temperatures, the bound water adsorbed on the surface of carbon black is heated and volatilized, resulting in mass loss. As the temperature increases, the mass loss of the modified carbon black is gradually greater than that of carbon black after 320°C, proving that the modifier adsorbed on the surface of carbon black is gradually decomposed by heat, indicating that the modification is successful.

[0110] As can be seen from Figure 4, by adjusting the ratio of the vulcanizing agent to the vulcanization accelerator, the cross-linked network structure of the prepared rubber composite material is different. Compared with the modified rubber composite materials prepared in Comparative Examples 3 and 4, the natural rubber composite material prepared in Example 3 and modified by synergistic vulcanization of graphene / carbon black of different particle sizes has the highest cross-linking density of 4.72×10-4mol / cm3, which proves that it has a developed cross-linking network, thereby improving the hardness and mechanical properties.

[0111] 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. Preparation of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire, characterized in that: The steps include: (1) during the stirring process, water, sodium methylene dinaphthalene sulfonate, sodium alkyl naphthalene sulfonate, KOH and casein are sequentially added into a high-speed mixer, quartz sand is added after they are completely dissolved, and then carbon black with different particle sizes is added, and the mixture is stirred at a certain speed for a certain time to obtain a surface-treated carbon black dispersion with different particle sizes; (2) adding deionized water to the graphene oxide aqueous dispersion, and then adding the surface-treated carbon black dispersion of different particle sizes obtained in step (1), and ultrasonicating at a certain power for a certain time to obtain a certain concentration of graphene oxide / carbon black of different particle sizes aqueous uniform dispersion; (3) adding deionized water to the natural rubber latex to obtain a natural rubber dispersion of a certain concentration after uniform dispersion, then adding the graphene oxide / carbon black water dispersion prepared in step (2), mechanically stirring at a certain rate for a certain time to obtain a uniform mixed solution, then adding a flocculant of a certain concentration to demulsify to obtain raw rubber, washing, dehydrating, and drying to obtain a graphene oxide / carbon black of different particle sizes modified natural rubber masterbatch; (4) placing the graphene oxide / carbon black of different particle sizes modified natural rubber masterbatch obtained in step (3) in an internal mixer, mixing at a certain temperature, adding an antioxidant, an antioxidant and a vulcanization accelerator in sequence and continuing to mix, then adding an activator and a softener and continuing to mix, discharging the rubber after mixing evenly and cooling to room temperature; mixing the obtained rubber material cooled to room temperature on a double roll of an open mixer at a certain temperature for a certain time, adding a vulcanizing agent sulfur, mixing evenly, passing the rubber material thinly until there are no bubbles in the rubber material, stopping mixing for a certain time, and obtaining a graphene / carbon black of different particle sizes synergistically modified natural rubber mixed rubber; (5) placing the rubber mixture obtained in step (4) into a mold, and vulcanizing it at a certain pressure and temperature for a certain time to obtain a graphene / carbon black of different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire.

2. The preparation of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 1, characterized in that: In step (1), the mass ratio of water, sodium methylene dinaphthalene sulfonate, sodium alkyl naphthalene sulfonate, KOH, casein, quartz sand and carbon black of different particle sizes is 720:1:0.5:1.5:3:150:

80.

3. The preparation of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 2, characterized in that: The carbon blacks with different particle sizes include N330 carbon black, carbon black N110, carbon black N660, and carbon black N765 in a mass ratio of 3:0-1:0-1:0-1, and the carbon black N110, carbon black N660, and carbon black N765 are not 0 at the same time.

4. The preparation method of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 1, characterized in that: In step (1), after adding carbon black of different particle sizes, the stirring speed is 400 to 6000 r / min and the stirring is carried out for 30 to 50 minutes.

5. The preparation method of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 1, characterized in that: In step (2), the concentration of the graphene oxide dispersion obtained after adding deionized water is 2 to 6 mg / mL; after adding carbon black dispersions of different particle sizes, the ultrasonic power is 100 to 300 W, and the ultrasonic time is 15 to 20 min.

6. The preparation method of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 1, characterized in that: In step (3), the concentration of the natural latex obtained after adding deionized water is 10 to 30 wt%.

7. The preparation method of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 1, characterized in that: In step (3), after adding the graphene oxide / carbon black aqueous dispersion of different particle sizes, the speed of mechanical stirring is 400 to 700 r / min, and the stirring time is 10 to 30 min.

8. The preparation method of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 1, characterized in that: In step (3), the graphene oxide content in the graphene oxide / carbon black of different particle sizes modified natural rubber masterbatch is 0.28wt.%, and the carbon black content is 44.3wt.%.

9. The preparation method of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 1, characterized in that: In step (4), the mass ratio of the natural rubber, antioxidant, antioxidant, vulcanization accelerator, activator, softener and vulcanizer is 100:1:1:1:5:2:3; the mixing temperature in the internal mixer is 110-120°C; the mixing temperature on the open mixer is 50-80°C, the double-roll speed is 12-20r / min, and the mixing time is 6-15min; the rubber stop time is 20-30h.

10. The preparation method of a graphene / carbon black with different particle sizes synergistically vulcanized and modified natural rubber long-life load-bearing tire according to claim 1, characterized in that: In step (5), the vulcanization pressure is 10-20 MPa, the vulcanization temperature is 140-160° C., and the vulcanization time is 5-20 min.

Images