Flame-retardant antistatic rubber track and preparation method and application thereof

Abstract

The application belongs to the technical field of rubber materials, and particularly relates to a kind of fire-retardant antistatic rubber track and its preparation method and application. The fire-retardant antistatic rubber track includes the following raw material components in parts by weight: natural rubber 40-60 parts, chlorobutyl rubber 40-60 parts, epoxidized natural rubber 5-12 parts, reinforcing agent 45-95 parts, chlorinated paraffin 10-40 parts, stearic acid 1-3 parts, modified composite flame retardant 23-60 parts, coupling agent 2-8 parts, accelerator 1-3 parts, vulcanizing agent 5-14 parts; the modified composite flame retardant is a composition modified by antimony trioxide, aluminum hydroxide and magnesium hydroxide in a mass ratio of 5-15:10-30:8-15. The application improves the fire-retardant performance while maintaining the physical properties and peeling performance by designing a new formula system, effectively solves the problems of fire-retardant and antistatic while maintaining the original performance of the rubber track, and provides a safety guarantee for mine operations.

Description

Technical Field

[0001] This invention belongs to the field of rubber material technology, specifically relating to a flame-retardant and antistatic rubber track, its preparation method, and its application. Background Technology

[0002] In complex environments such as mines with high humidity and dust, traditional running gear, such as tires, pose numerous safety hazards due to their susceptibility to slipping, getting stuck, and tipping over. Similarly, metal tracks frequently cause accidents due to friction sparks and static electricity igniting methane gas. Rubber tracks, a new type of running gear developed to mimic metal tracks, offer superior longitudinal flexibility and lateral stiffness and toughness. They also boast advantages such as low ground pressure, good adhesion, low vibration, low noise, good wetland performance, no road damage, high speed, and light weight, making them widely used in various fields.

[0003] Currently, traditional rubber tracks mostly use a blend of natural rubber (NR) and styrene-butadiene rubber (SBR). However, in complex environments such as high humidity and dust in mines, these tracks need to meet the flame retardant and antistatic requirements of MT113, while also considering the potential for delamination at the metal skeleton-rubber interface due to stress concentration. Existing technology uses an antimony trioxide / chlorinated paraffin / aluminum hydroxide flame retardant system, requiring a total flame retardant content of 30% to achieve the required flame retardancy and antistatic properties. However, this results in a 20%-30% decrease in the physical and mechanical properties of the rubber track and a 25%-40% decrease in peel strength, making it difficult to meet vehicle performance requirements. Therefore, developing a rubber track that balances excellent performance with flame retardant and antistatic properties suitable for mining environments is of great significance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a flame-retardant and antistatic rubber track, its preparation method, and its application. This flame-retardant and antistatic rubber track improves flame-retardant performance while maintaining physical and peel properties through a newly designed formulation system. It effectively solves the flame-retardant and antistatic problems while preserving the original performance of the rubber track, providing a strong guarantee for mine operations, especially coal mine operations.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The first objective of this invention is to provide a flame-retardant and antistatic rubber track, which, by weight, comprises the following raw material components: 40-60 parts of natural rubber, 40-60 parts of chloroprene rubber (CR), 5-12 parts of epoxidized natural rubber, 45-95 parts of reinforcing agent, 10-40 parts of chlorinated paraffin, 1-3 parts of stearic acid, 23-60 parts of modified composite flame retardant, 2-8 parts of coupling agent, 1-3 parts of accelerator, and 5-14 parts of vulcanizing agent;

[0007] The modified composite flame retardant is a modified composite composition of antimony trioxide, aluminum hydroxide, and magnesium hydroxide in a mass ratio of 5-15:10-30:8-15.

[0008] Magnesium hydroxide and aluminum hydroxide can be used as flame retardants, but if the rubber compound is halogen-free, their filler content needs to be as high as 35-55%. Even with the addition of chlorinated paraffin as a chlorine donor, traditional rubber systems (NR+SBR) require a 35% filler content to achieve a flame-retardant effect, but excessive filler content significantly impacts performance, causing rubber tracks to lose their usability. Due to the rigid inorganic structure of magnesium hydroxide and aluminum hydroxide, they lack effective adhesion to the rubber interface, are prone to agglomeration, and have poor compatibility with rubber, easily forming stress concentration points, leading to further reduction in physical and mechanical properties. This invention, through compounding and modifying flame retardants, can significantly enhance the bonding force between the modified composite flame retardant and the rubber interface while reducing the dosage, greatly improving the uniformity of mixing and dispersion, shortening the mixing time, and reducing the surface roughness of the product, thus significantly reducing the risk of flame retardant agglomeration and stress concentration.

[0009] Chloroprene rubber (C1) contains chlorine atoms (Cl) that exist stably in the main chain in a covalent bond form. The presence of halogens inherently endows it with excellent flame retardancy, and the polarity of chlorine atoms significantly enhances its corrosion resistance. However, blending C1 with natural rubber drastically reduces the physical and mechanical properties of the compound. This invention modifies the blend matrix of C1 and natural rubber by adding epoxidized natural rubber, improving the compatibility of the blend matrix and further enhancing the physical and mechanical properties of the blend. By optimizing the flame retardant system and applying a modified composite flame retardant to produce a synergistic effect with the halogens and chlorinated paraffins in the blend matrix, in-situ bonding of the flame retardant with rubber molecules is achieved. This reduces the amount of flame retardant used and improves the flameless combustion effect. The resulting flame-retardant and antistatic rubber track maintains the physical and peel performance of existing rubber tracks while meeting the MT113 performance requirements, making it suitable for various mine applications and showing broad application prospects.

[0010] Furthermore, in the above technical solution, the reinforcing agent is a composition of silica, carbon black, and silicate in a mass ratio of 5-25:30-50:10-20. The silicate is prepared by processes such as celery shavings, the addition of modifiers, and activation treatment.

[0011] Traditional rubber track products, due to excessive carbon black filling, significantly enhance the physical properties of rubber but also prolong the product's burning time. Silicates, composed of inert components, possess excellent durability, weather resistance, and corrosion resistance. This technical solution modifies the reinforcing agent ratio, reducing carbon black usage and increasing silica and silicates. This maintains physical properties while improving antistatic properties and reducing the impact of carbon black on burning time. Simultaneously, silica and silicates are rich in silanol groups, which can form hydrogen bonds and chemical bonds with the oxide layer of metal surfaces, significantly improving interfacial adhesion. This compensates for the loss of rubber-metal bonding properties due to excessive flame retardant filling and reduces premature failure of rubber tracks caused by moisture entering the adhesive layer in high-humidity environments.

[0012] Furthermore, in the above technical solution, the modification method of the modified composite flame retardant includes the following steps:

[0013] (1) Add aluminum hydroxide and magnesium hydroxide to a mixed solution of water and ethanol according to the mass ratio to prepare a 45% slurry. Stir and heat the mixture. Stop heating when the system temperature reaches 90°C.

[0014] (2) Add 1.5% of the modifier in the total mass of the modified composite flame retardant, continue the reaction, cool after the reaction is completed, filter out the material, and dry to obtain the surface-coated modified semi-finished product composition.

[0015] (3) According to the mass ratio, add antimony trioxide and the semi-finished product composition obtained in step (2) into a high-speed mixer, premix for a period of time, and after the temperature reaches 120-130℃, add 0.5% of the total mass of the modified composite flame retardant composition as a modifier, stir for 20-30 minutes, and then cool and discharge the material by low-speed stirring.

[0016] Furthermore, in the above technical solution, the modifier is a composition of γ-aminopropyltriethoxysilane and isopropyltris(dioctylpyrophosphoryloxy)titanate in a mass ratio of 5:3, and the stirring speed is 1000-1500 r / min.

[0017] Furthermore, in the above technical solution, the epoxidation degree of the epoxidized natural rubber is 50%; the coupling agent is SI-50GE. SI-50GE is a mixture of bis-[γ-(triethoxysilyl)propyl]tetrasulfide and EPDM, with bis-(triethoxysilyl)propyl)tetrasulfide as the main component. As a compatibilizer, the epoxidized natural rubber forms physical entanglement points in the NR / CR blend due to its epoxidized structure, while releasing flexible epoxy rings to balance the rigidity of NR and the toughness of CR, reducing the interfacial tension between the two phases; at the same time, the coupling agent can also promote more uniform dispersion of silica, silicates, and modified composite flame retardants in the rubber compound.

[0018] Furthermore, in the above technical solution, the accelerator is dibenzothiazole disulfide (DM).

[0019] Furthermore, in the above technical solution, the vulcanizing agent is a composition of active magnesium oxide, nano zinc oxide, and insoluble sulfur in a mass ratio of 1-5:3-6:1-3. This technical solution utilizes a sulfur / peroxide double vulcanization system to form a reversible cross-linking network, improving the fatigue resistance of the rubber compound while simultaneously increasing the cross-linking density and reducing the migration rate of the flame retardant, thus providing support for flame retardant performance.

[0020] The second objective of this invention is to provide a method for preparing a flame-retardant and antistatic rubber track, comprising the following steps:

[0021] (1) Plasticizing: First, add natural rubber to the internal mixer, press it, and after reaching the temperature, discharge the rubber and transfer it to the open mill. Adjust the roller gap to 7-8mm, roll it evenly with the rollers, cut it with the left and right cutters, cut it off, and pound it 4-6 times. Roll it up, adjust the roller gap to within 1mm, make a thin triangular wrap, and let it stand for 8-48 hours.

[0022] (2) First stage of mixing: The natural rubber triangular package from step (1) is added to the epoxidized natural rubber, chloroprene rubber, reinforcing agent and coupling agent and pressed into the internal mixer for 200s, the pressing is lifted, some chlorinated paraffin and some accelerator are added, and after cleaning, it is pressed again. After reaching the temperature, the rubber is discharged and transferred to the open mill. The roller gap is adjusted to 7-8mm. After the roll is rolled evenly, the left and right cutters are used to cut and tamp 4-6 times. The sheet is then cooled and left and right and left and left and right and left and right and left and right and left and right and left and left and right and left and right and left and right and left and right and left and right and left and right and left and right and left and right and left and right and left and right and left and right and left and right and left and left and right for 8-48h. By adding some DM in the early stage of mixing, the scorching and processing performance of chloroprene rubber can be improved without affecting the vulcanization effect of natural rubber.

[0023] (3) Two-stage mixing: Add the first-stage mixing compound, the remaining chlorinated paraffin, the modified composite flame retardant, the active magnesium oxide, and stearic acid from step (2) to the internal mixer, press for 150s, clean and press again, discharge the rubber after reaching the temperature, transfer to the open mill, adjust the roller gap to 8-10mm, roll evenly with the roller, cut with left and right cutters, cut off, and pound 4 times, then sheet out and cool, and let stand for 8-48h; By adding the modified composite flame retardant and active magnesium oxide at the same time in the middle of the mixing, the MgO layer released by the active magnesium oxide when heated can reflect heat radiation, which further improves the oxygen index of the CR / flame retardant system;

[0024] (4) Refining: Add the two-stage compound, nano zinc oxide, insoluble sulfur and remaining accelerator from step (3) to the internal mixer, press the roller for 60s, lift the roller, clean and press the roller again, discharge the rubber after reaching the temperature, transfer it to the open mill, adjust the roller gap to 5-7mm, roll it evenly with the roller wrapping, cut it with the left and right cutter, cut it off, and pound it twice, then sheet it out and let it stand for 8-48 hours to obtain the final compound;

[0025] (5) Flat vulcanization: The final rubber after step (4) is mixed with metal skeleton materials such as core metal to prepare preforms, and then put into molds with materials such as steel wire curtains, and vulcanized at 150°C in a flat vulcanizing machine to obtain rubber track products.

[0026] This invention employs a segmented preparation process. First, natural rubber is plasticized. Then, epoxidized natural rubber is mixed with chloroprene rubber, reinforcing agents, coupling agents, etc., in a first-stage mixing process. Next, flame retardants, active magnesium oxide, etc., are added for a second-stage mixing process. Finally, the remaining additives are added for further mixing. After sheeting, the mixture is vulcanized. Through multiple mixing processes, the raw materials are more uniformly mixed and have good dispersibility. At the same time, the processing properties of the NR and CR blend matrix can be adjusted, balancing the vulcanization characteristics and scorch performance of the blend. The resulting flame-retardant and antistatic rubber track not only has excellent physical properties and peel performance but also meets the flame-retardant performance requirements of MT113, making it widely applicable in various types of mines.

[0027] Furthermore, in the above technical solution, in step (1), the rotor speed of the internal mixer is 30 r / min, the pressure is 6-7 MPa, the initial temperature of the mixing chamber is 60℃, and the temperature of the internal mixing discharge is 130-135℃; the speed ratio of the front and rear rollers of the open mill is 1:1.19, the linear speed of the front roller is 28.55 m / min, the temperature of the front roller is 45-55℃, and the temperature of the rear roller is 55-65℃.

[0028] Furthermore, in the above technical solution, in step (2), the temperature of internal mixing and degreasing is 140-145℃; in step (3), the temperature of internal mixing and degreasing is 135-140℃; in step (4), the temperature of internal mixing and degreasing is 95-105℃.

[0029] The third objective of this invention is to provide an application of the aforementioned flame-retardant and antistatic rubber track in various coal mines and metal mines. Testing has shown that the flame-retardant and antistatic rubber track prepared by this invention exhibits excellent overall performance, particularly low surface resistivity and flammability, as well as superior antistatic and flame-retardant properties. It can be applied to various coal mines and also has broad application prospects in various high-humidity, high-dust environments of metal mines such as tin, gold, silver, copper, and iron mines.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention, by compounding and modifying flame retardants, can significantly enhance the interfacial bonding force between modified composite flame retardants and rubber while reducing the amount of each compound, greatly improving the uniformity of mixing and dispersion, shortening the mixing time, reducing the surface roughness of the product, and significantly reducing the risk of flame retardant agglomeration and stress concentration.

[0032] This invention optimizes the raw rubber system and flame retardant system of rubber track formulations. It replaces halogen-free styrene-butadiene rubber with chloroprene rubber and utilizes a modified composite flame retardant to achieve a synergistic effect with halogens and chlorinated paraffins in the NR / CR blend matrix, enabling in-situ bonding between the flame retardant and rubber molecules. This reduces the amount of flame retardant used and improves the flameless combustion effect. Furthermore, by adding epoxidized natural rubber to modify the NR / CR blend matrix, compatibility is improved, further enhancing the physical and mechanical properties of the blend. Finally, by altering the reinforcing agent formulation, reducing carbon black and increasing the amounts of silica and silicates, antistatic properties are improved while maintaining physical performance. The system improves electrical properties and reduces the impact of carbon black on combustion time, compensates for the loss of rubber-metal adhesion due to the large amount of flame retardant filling, and reduces the phenomenon of premature failure of rubber tracks caused by moisture entering the adhesive layer in high humidity environments. By adopting a sulfur / peroxide double vulcanization system to form a reversible cross-linking network, the fatigue resistance of the rubber compound is improved, while the cross-linking density is increased and the migration rate of flame retardants is reduced, providing support for flame retardant performance. The resulting flame-retardant rubber track not only maintains the physical properties and peel performance, but also improves the product processing performance and physical properties, and effectively solves the problems of flame retardancy and antistatic properties, providing a strong guarantee for safety in mining operations.

[0033] This invention employs a segmented preparation process, involving multiple mixing processes to achieve more uniform mixing and better dispersibility of raw materials. It also allows for adjustment of the processing properties of the NR and CR blend matrix, balancing the vulcanization characteristics and scorch performance of the blended rubber. The resulting flame-retardant and antistatic rubber track not only boasts excellent physical and peel properties but also meets the flame-retardant performance requirements of MT113. It can be applied in various mines and has broad application prospects. Detailed Implementation

[0034] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the raw materials used in the following examples are all commercially available products and can be purchased from the market.

[0035] The above-described technical features of the present invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions.

[0036] The raw materials involved in the various embodiments of the present invention are either existing commercially available products or can be prepared according to existing methods, and the testing methods are industry-standard methods.

[0037] The rotor speed of the X(S)N-110 / 30 type internal mixer used in this invention is 30 r·min. -1 The pressure is 6-7 MPa, and the initial temperature of the mixing chamber is 60℃;

[0038] The X(S)K-550 open-type rubber mixing mill has a front and rear roller speed ratio of 1:1.19, a front roller linear speed of 28.55m / min, a front roller temperature of 45-45℃, and a rear roller temperature of 55-65℃.

[0039] Example 1

[0040] The modification method for modified composite flame retardants includes the following steps:

[0041] (1) Add aluminum hydroxide and magnesium hydroxide to a mixed solution of water and ethanol (volume ratio of 1:1) by mass ratio to prepare a 45% slurry. Stir and heat at 1000 r / min. Stop heating when the system temperature reaches 90℃.

[0042] (2) Add 1.5% of the modifier in the total mass of the modified composite flame retardant, continue the reaction, cool after the reaction is completed, filter out the material, and dry to obtain the surface-coated modified semi-finished product composition.

[0043] (3) According to the mass ratio, add antimony trioxide and the semi-finished product composition obtained in step (2) into a high-speed mixer, premix for a period of time, and after the temperature reaches 125°C, add 0.5% of the total mass of the modified composite flame retardant composition as a modifier, and then stir at a speed of 1250r / min for 20min. After stirring and cooling at a low speed (200r / min), the product is obtained.

[0044] The modifier is a composition of γ-aminopropyltriethoxysilane (KH550) and isopropyltris(dioctylpyrophosphoryloxy)titanate in a mass ratio of 5:3.

[0045] Example 2

[0046] A flame-retardant and antistatic rubber track, by weight, comprises the following raw material components: 60 parts natural rubber, 40 parts chloroprene rubber, 10 parts epoxidized natural rubber, 65 parts reinforcing agent, 20 parts chlorinated paraffin, 2 parts stearic acid, 38 parts modified composite flame retardant, 2 parts coupling agent, 2 parts accelerator, and 10.5 parts vulcanizing agent.

[0047] The reinforcing agent is a composition of silica, carbon black N220, and silicate in a mass ratio of 10:40:15; the epoxidation degree of the epoxidized natural rubber is 50%; the modified composite flame retardant is a composition of antimony trioxide, aluminum hydroxide, and magnesium hydroxide in a mass ratio of 8:20:10, and is prepared according to the method of Example 1; the coupling agent is SI-50GE; the accelerator is dibenzothiazole disulfide (DM); and the vulcanizing agent is a composition of active magnesium oxide, nano zinc oxide, and insoluble sulfur in a mass ratio of 3.5:5:2.

[0048] Its preparation method includes the following steps:

[0049] (1) Plasticizing: First, add natural rubber to the internal mixer, and after pressing (holding for 190s), lifting the pressing, pressing (holding for 240s) the rubber is discharged at 135℃ and transferred to the open mill. Adjust the roller gap to 7-8mm, roll the rubber evenly, cut it with left and right cutters, cut it off, and pound it 5 times. Roll it up, adjust the roller gap to within 1mm, make a thin triangular wrap, and let it stand for 20h.

[0050] (2) First stage of mixing: The natural rubber triangular package from step (1) is added to the internal mixer and pressed for 200s with epoxidized natural rubber, chloroprene rubber, reinforcing agent, coupling agent SI-50GE, and the pressing is lifted. Part of chlorinated paraffin and part of accelerator DM are added. After cleaning, the mixture is pressed again (for 150s). After reaching 145℃, the rubber is discharged and transferred to the open mill. The roller gap is adjusted to 7-8mm. After rolling evenly with the rollers, the left and right cutters are used to cut and tamp the mixture 5 times. The sheet is then cooled and left to stand for 20h.

[0051] (3) Two-stage mixing: Add the first-stage mixing rubber compound, the remaining chlorinated paraffin, the modified composite flame retardant, the active magnesium oxide, and the stearic acid from step (2) to the internal mixer, press the roller for 150s, lift the roller, clean the roller and press it again. After reaching 140℃, discharge the rubber and transfer it to the open mill. Adjust the roller gap to 8-10mm, roll it evenly with the roller wrapping, cut it with the left and right cutters, cut it off, and pound it 4 times. Remove the sheet and cool it. Let it stand for 30h.

[0052] (4) Refining: Add the two-stage compound, vulcanizing agent nano zinc oxide, insoluble sulfur and remaining accelerator from step (3) to the internal mixer. After pressing with a roller for 60s, lifting the roller, cleaning and pressing again, discharge the rubber after reaching 100℃, transfer it to the open mill, adjust the roller gap to 5-7mm, roll it evenly with a wrapping roller, cut with left and right cutters, cut off, and pound twice, then sheet it out and let it stand for 30h to obtain the final compound.

[0053] (5) Vulcanization: The final rubber after step (4) is prepared into a preform with metal skeleton materials such as core metal, and then put into a mold with materials such as steel wire curtain, and vulcanized at 150°C in a flat vulcanizing machine to obtain rubber track products.

[0054] Comparative Example 2

[0055] A flame-retardant and antistatic rubber track, the raw material formula of which is shown in Table 1, and its preparation method includes the following steps:

[0056] (1) Plasticizing: First, add natural rubber to the internal mixer, and after pressing (holding for 190s), lifting the pressing, pressing (holding for 240s) the rubber is discharged at 135℃ and transferred to the open mill. Adjust the roller gap to 7-8mm, roll the rubber evenly, cut it with left and right cutters, cut it off, and pound it 5 times. Roll it up, adjust the roller gap to within 1mm, make a thin triangular wrap, and let it stand for 20h.

[0057] (2) Mixing: Add the triangular bag, epoxidized natural rubber, chloroprene rubber, reinforcing agent, stearic acid, coupling agent, chlorinated paraffin, modified composite flame retardant and active magnesium oxide from step (1) to the internal mixer and press for 200s, lift the pressing wheel, clean and press again (hold for 150s), and discharge the rubber after reaching 155℃. Transfer to the open mill, adjust the roller gap to 7-8mm, roll evenly with the rollers, cut with left and right cutters, cut off and tamp 5 times, and then cut off the sheet and cool it. Let it stand for 20h.

[0058] (3) Refining: Add the mixed rubber compound, nano zinc oxide, insoluble sulfur and accelerator from step (2) to the internal mixer, press the roller for 60s, lift the roller, clean and press the roller again, discharge the rubber after reaching 100℃, transfer it to the open mill, adjust the roller gap to 5-7mm, roll it evenly with the roller wrapping, cut it with the left and right cutter, cut it off, and pound it twice, then sheet it out and let it stand for 30h to obtain the final rubber compound;

[0059] (4) Vulcanization: The final rubber after step (3) is prepared into a preform with metal skeleton materials such as core metal, and then put into a mold with materials such as steel wire curtain, and vulcanized at 150°C in a flat vulcanizing machine to obtain rubber track products.

[0060] Comparative Example 6

[0061] A traditional rubber track, the raw material formula of which is shown in Table 1, is prepared by the following steps:

[0062] (1) Plasticizing: First, add natural rubber and styrene-butadiene rubber to the internal mixer. After pressing (holding for 190s), lifting the pressing, pressing (holding for 240s) process, discharge the rubber at 135℃, transfer it to the open mill, adjust the roller gap to 7-8mm, roll the roller evenly, cut with left and right cutter, cut off, tamp 5 times, roll, adjust the roller gap to within 1mm, thin pass through triangular wrap, and let it stand for 20h;

[0063] (2) Mixing: Add the triangular bag, other raw materials except insoluble sulfur and accelerator from step (1) to the internal mixer and press for 200s, lift the pressing, clean and press again (hold for 150s), and discharge the glue after reaching 155℃. Transfer to the open mill, adjust the roller gap to 7-8mm, roll evenly with the rollers, cut with left and right cutters, cut off, and pound 5 times. Cut off the sheet and cool it, and let it stand for 20h.

[0064] (3) Refining: Add the mixed rubber, insoluble sulfur and accelerator from step (2) to the internal mixer, press the roller for 60s, lift the roller, clean and press the roller again, discharge the rubber after reaching 100℃, transfer it to the open mill, adjust the roller gap to 5-7mm, roll it evenly with the roller wrapping, cut it with the left and right cutter, cut it off, and pound it twice, then produce the sheet, let it stand for 30h to obtain the final rubber;

[0065] (4) Vulcanization: The final rubber after step (3) is prepared into a preform with metal skeleton materials such as core metal, and then put into a mold with materials such as steel wire curtain, and vulcanized at 150°C in a flat vulcanizing machine to obtain rubber track products.

[0066] The raw material formulations of Examples 2-5 and Comparative Examples 1-6 are shown in Table 1. The preparation methods of the modified composite flame retardants of Examples 2-5 and Comparative Examples 1-3 are the same as those of Example 1. The flame retardant in Comparative Example 4 is obtained by directly mixing the various compositions. The preparation methods of the rubber tracks of Examples 3-5 and Comparative Example 1 are the same as those of Example 2. The preparation methods of the rubber tracks of Comparative Examples 3-5 are the same as those of Comparative Example 6.

[0067] Table 1. Weight proportions of raw materials in each embodiment and comparative example

[0068]

[0069] The mechanical properties, abrasion resistance, resilience, hardness, antistatic properties, and flammability of the rubber tracks prepared in Examples 2-5 and Comparative Examples 1-6 were tested, and the results are shown in Tables 2 and 3. Tensile strength was tested using the relevant methods of GB / T 528-2009, tear strength using the relevant methods of GB / T 529-2008, Akron abrasion using the relevant methods of GB / T 1689-2014, impact elasticity using the relevant methods of GB / T 1681-2009, flexural cracking test using the relevant methods of GB / T 13934-2006, peel strength using the method of ISO 813:2019, hardness using the relevant methods of GB / T 531.1-2008, and flame retardancy and antistatic properties using the relevant methods of MT113-1995.

[0070] Table 2 Performance test results of Examples 2-5

[0071]

[0072] Table 3 Performance test results of Comparative Examples 1-6

[0073]

[0074] As can be seen from the results in Table 2, the flame-retardant and antistatic rubber track obtained by the formulation of the present invention has excellent comprehensive performance, especially with low surface resistance and flammability, excellent antistatic and flame-retardant properties, and can be used in mining operations with good safety and wear resistance.

[0075] As can be seen from the results in Table 3, Comparative Example 1, which did not include epoxidized natural rubber, showed a significant decrease in both physical and mechanical properties and peel performance compared to Example 1, as well as a substantial reduction in flame retardancy. Comparative Example 2, which did not employ multi-stage mixing and segmented feeding processes, had a longer mixing time and a significantly shorter scorch time, resulting in poor physical and mechanical properties, peel performance, and dispersibility. The overall performance of Comparative Example 2 after the addition of epoxidized natural rubber was slightly inferior to Comparative Example 1, failing to meet the high-performance requirements of rubber tracks. Comparative Example 3, which did not use halogen-containing chloroprene rubber to replace styrene-butadiene rubber, exhibited a weak synergistic effect. Even with composite modification of the flame retardant, the flame retardant filling amount still had to reach 20% to achieve the MT113 flame retardant effect, leading to a 45% decrease in peel performance compared to traditional tracks. In Example 4, no silicate was added to Comparative Example 3, and the flame retardant was simply mixed without modification. The required flame retardant filling amount reached 34%. The large amount of flame retardant resulted in a 56% decrease in peel performance compared to traditional tracks, and its overall performance further declined, especially the mechanical properties and antistatic properties. This indicates that adding silicate to the reinforcing agent can improve the antistatic properties. In Comparative Example 5, the flame retardant was only antimony trioxide and chlorinated paraffin in synergy, which further reduced its antistatic and flame retardant properties. In particular, its flameless combustion could not meet the MT113 standard. Comparative Example 6 used a traditional track formula. Although it had better mechanical properties, its antistatic properties were poor and it could not self-extinguish after ignition, thus failing to meet the MT113 requirements for the flame retardant performance of tracks.

[0076] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flame-retardant and antistatic rubber track, characterized in that, By weight, the flame-retardant and antistatic rubber track comprises the following raw material components: 40-60 parts natural rubber, 40-60 parts chloroprene rubber, 5-12 parts epoxidized natural rubber, 45-95 parts reinforcing agent, 10-40 parts chlorinated paraffin, 1-3 parts stearic acid, 23-60 parts modified composite flame retardant, 2-8 parts coupling agent, 1-3 parts accelerator, and 5-14 parts vulcanizing agent; The modified composite flame retardant is a modified composite composition of antimony trioxide, aluminum hydroxide, and magnesium hydroxide in a mass ratio of 5-15:10-30:8-15. The reinforcing agent is a composition of silica, carbon black, and silicate in a mass ratio of 5-25:30-50:10-20. The modification method of the modified composite flame retardant includes the following steps: (1) Add aluminum hydroxide and magnesium hydroxide to a mixed solution of water and ethanol according to the mass ratio to prepare a 45% slurry. Stir and heat the mixture. Stop heating when the system temperature reaches 90°C. (2) Add 1.5% of the total mass of the modified composite flame retardant to the modifier, continue the reaction, cool after the reaction is completed, filter out the material, and dry to obtain the surface-coated modified semi-finished product composition. (3) According to the mass ratio, add antimony trioxide and the semi-finished product composition obtained in step (2) into a high-speed mixer, premix for a period of time, and after the temperature reaches 120-130℃, add 0.5% of the total mass of the modified composite flame retardant composition as a modifier, stir for 20-30 minutes, and then cool and discharge the material by low-speed stirring; the modifier is a composition of γ-aminopropyltriethoxysilane and isopropyltris(dioctylpyrophosphoryloxy)titanate in a mass ratio of 5:3, and the stirring speed is 1000-1500r / min.

2. The flame-retardant and antistatic rubber track according to claim 1, characterized in that, The epoxidized natural rubber has an epoxidation degree of 50%; the coupling agent is SI-50GE.

3. The flame-retardant and antistatic rubber track according to claim 1, characterized in that, The accelerator is dibenzothiazole disulfide; the sulfiding agent is a composition of active magnesium oxide, nano zinc oxide and insoluble sulfur in a mass ratio of 1-5:3-6:1-3.

4. The method for preparing a flame-retardant and antistatic rubber track as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Plasticizing: First, add natural rubber to the internal mixer, press it, and after reaching the temperature, discharge the rubber and transfer it to the open mill. Adjust the roller gap to 7-8mm, roll it evenly with the rollers, cut it with the left and right cutters, cut it off, and pound it 4-6 times. Roll it up, adjust the roller gap to within 1mm, make a thin triangular wrap, and let it stand for 8-48 hours. (2) First stage of mixing: Add the natural rubber triangular bag from step (1) along with epoxidized natural rubber, chloroprene rubber, reinforcing agent, and coupling agent to the internal mixer and press for 200s. Remove the pressing wheel, add some chlorinated paraffin and some accelerator, clean and press again. After reaching the temperature, discharge the rubber and transfer it to the open mill. Adjust the roller gap to 7-8mm. After rolling evenly with the rollers, cut with left and right cutters, cut off, and pound 4-6 times. Cut the sheet and cool it. Let it stand for 8-48 hours. (3) Two-stage mixing: Add the first-stage mixing compound, the remaining chlorinated paraffin, the modified composite flame retardant, the active magnesium oxide, and the stearic acid from step (2) to the internal mixer, press for 150s, clean and press again, discharge the rubber after reaching the temperature, transfer to the open mill, adjust the roller gap to 8-10mm, roll evenly with the wrapping roller, cut with the left and right cutters, cut off, and pound 4 times, then sheet out and cool, and let stand for 8-48h. (4) Refining: Add the two-stage compound, nano zinc oxide, insoluble sulfur and remaining accelerator from step (3) to the internal mixer, press the roller for 60s, lift the roller, clean and press the roller again, discharge the rubber after reaching the temperature, transfer it to the open mill, adjust the roller gap to 5-7mm, roll it evenly with the roller wrapping, cut it with the left and right cutter, cut it off, and pound it twice, then sheet it out and let it stand for 8-48 hours to obtain the final compound; (5) Flat vulcanization: The final rubber after step (4) is mixed with the core metal skeleton material to prepare a preform, and then the steel wire cord material is placed in the mold and vulcanized at 150°C in a flat vulcanizing machine to obtain the rubber track product.

5. The method for preparing a flame-retardant and antistatic rubber track according to claim 4, characterized in that, In step (1), the rotor speed of the internal mixer is 30 r / min, the pressure is 6-7 MPa, the initial temperature of the mixing chamber is 60℃, and the temperature of the discharge of the internal mixer is 130-135℃; the speed ratio of the front and rear rollers of the open mill is 1:1.19, the linear speed of the front roller is 28.55 m / min, the temperature of the front roller is 45-55℃, and the temperature of the rear roller is 55-65℃.

6. The method for preparing a flame-retardant and antistatic rubber track according to claim 4, characterized in that, In step (2), the temperature for internal mixing and degreasing is 140-145℃; in step (3), the temperature for internal mixing and degreasing is 135-140℃; in step (4), the temperature for internal mixing and degreasing is 95-105℃.

7. The application of a flame-retardant and antistatic rubber track as described in any one of claims 1-3 or a flame-retardant and antistatic rubber track prepared by the preparation method described in any one of claims 4-6 in various coal mines and metal mines.

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