Aramid fiber rope conveyor belt and method of making same

Abstract

This invention relates to an aramid rope conveyor belt and its preparation method, belonging to the field of conveyor belt manufacturing technology. The aramid rope conveyor belt, by mass fraction, comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer; the aramid rope core layer comprises modified aramid fibers; the elastic buffer layer, by mass fraction, comprises high-saturation nitrile rubber, carbon black, peroxide, and plasticizer; the composite coating, by mass fraction, comprises, from the outside to the inside, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer; the hydrophobic wear-resistant layer comprises modified polyurethane, nano-ZnO, zinc stearate, titanate coupling agent, and defoamer; the barrier layer comprises fluororubber, polyvinylidene chloride, and nano-montmorillonite; and the filler layer comprises polytetrafluoroethylene nano-dispersion, nano-graphene, and silane coupling agent. The aramid rope conveyor belt of this invention can adapt to high-humidity and high-salt-spray environments such as ports, extending the service life of the conveyor belt.

Description

Technical Field

[0001] This invention relates to the field of conveyor belt manufacturing technology, and in particular to an aramid rope conveyor belt and its manufacturing method. Background Technology

[0002] Conveyor belts are one of the main components of belt conveyors, primarily used for large-scale, continuous transportation in sectors such as coal mining, metallurgy, chemicals, construction, and transportation. Currently, steel cord conveyor belts are widely used both domestically and internationally, employing steel cords as the core and rubber as the covering. To increase the adhesion between the steel cord and rubber, not only is the steel cord copper- or zinc-plated, but cobalt salts and other materials are also added to the intermediate rubber layer, increasing formulation costs. Furthermore, cobalt salts are radioactive, posing potential environmental and health risks. Steel cords are typically either left- or right-hand twisted, spaced alternately throughout the conveyor belt. High-strength conveyor belts mostly utilize steel cord rubber conveyor belts, but these require a large amount of metal material—steel cord—increasing both production and transportation costs due to its weight, and resulting in significant wasted energy during operation. To overcome these shortcomings, those skilled in the art have developed aramid cord conveyor belts. Due to their excellent mechanical properties and lightweight characteristics, aramid materials are gradually becoming an ideal choice for conveyor belt skeleton materials.

[0003] Chinese invention patent application CN103264866A discloses a high-temperature resistant aramid conveyor belt and its preparation process. The process involves coating the working surface with a cover adhesive, the raw material composition of which is: 90 parts EPDM rubber; 7.5 parts vulcanizing agent DCP; 0.75 parts accelerator DM; 2 parts accelerator TT; 7.5 parts zinc oxide; 2 parts stearic acid; 3.5 parts antioxidant RD; 11 parts TCP flame retardant; 4 parts chlorinated paraffin; 5.5 parts terpene resin; 6.5 parts coumarone resin; 30 parts N330 carbon black; 30 parts N220 carbon black; 3 parts epoxy resin; 0.75 parts diethylenetriamine; 0.75 parts sulfur; 7.5 parts aramid short fiber; and 2 parts cage-type octapolyvinylsilsesquioxane.

[0004] The aramid rope conveyor belt provided by this invention completely combines aramid fiber cloth with an adhesive layer, featuring high temperature resistance, good tear resistance, and long service life; it can be used for 123 days at 250℃. Although the aforementioned aramid rope conveyor belt is heat-resistant, long-term exposure to the high humidity and high salt spray environment of ports can cause the amide bonds (-CONH-) in the aramid (poly(p-phenylene terephthalamide)) molecular chain to undergo hydrolysis with water molecules in a prolonged humid environment. This leads to molecular chain breakage and a significant decrease in fiber tensile strength, especially under high temperature and humidity conditions, where the degradation rate accelerates, and the chloride ions (Cl-) in the salt spray... -It has strong permeability and can penetrate into the interior of aramid fibers, combine with polar groups in the fiber molecular chain, destroy the structural stability, generate mechanical stress when salt crystallizes and precipitates, causing microcracks inside the fiber to expand, thereby making the fiber brittle and reducing its fatigue resistance. Summary of the Invention

[0005] To address the technical challenges of using aramid rope conveyor belts in high-humidity, high-salt-fog environments such as ports, this invention provides an aramid rope conveyor belt and its manufacturing method. The aramid rope conveyor belt of this invention can adapt to high-humidity, high-salt-fog environments such as ports, extending the service life of the conveyor belt.

[0006] In a first aspect, the present invention provides an aramid rope conveyor belt, which comprises, from the outside to the inside: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 3-5:8-14:1.

[0007] The aramid rope core layer comprises modified aramid fibers.

[0008] The elastic buffer layer comprises 95-105 parts of high-saturation nitrile rubber, 25-35 parts of carbon black, 2-4 parts of peroxide, and 1-3 parts of plasticizer.

[0009] The composite coating comprises, from the outside in, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer, with the thickness ratio of the hydrophobic wear-resistant layer, the barrier layer, and the filler layer being 1:1 to 2:1.

[0010] The hydrophobic and wear-resistant layer comprises 85-90% modified polyurethane, 3-5% nano ZnO, 3-5% zinc stearate, 2-3% titanate coupling agent, and 1-2% defoamer; the barrier layer comprises 65-70% fluororubber, 25-30% polyvinylidene chloride, and 2-4% nano montmorillonite; and the filler layer comprises 93-97% polytetrafluoroethylene nanodispersion, 2-4% nano graphene, and 1-3% silane coupling agent.

[0011] In the above technical solution, in the hydrophobic wear-resistant layer, modified polyurethane reduces surface energy, inhibits the spreading of salt spray droplets, and reduces the risk of corrosion caused by salt crystallization, thus protecting Cl... - The osmosis of Cl also acts as a barrier, blocking its penetration. - This facilitates the diffusion of water molecules, preventing droplet retention and hydrolysis. Nano-ZnO, as a hard filler, enhances the coating's wear resistance. The alkoxy group at one end of the titanate coupling agent reacts with the hydroxyl groups on the ZnO surface. Surface treatment with the titanate coupling agent improves the dispersibility of ZnO in the modified polyurethane. The other end binds to the polar groups of the modified polyurethane, increasing the filler-matrix interface strength and preventing agglomeration. Zinc stearate long-chain alkyl (C...) 18 H 35Defoamers can reduce the surface energy of the coating. They can also reduce the surface tension of the coating slurry and break up bubbles generated during mixing and coating.

[0012] In the barrier layer, the high bond energy of the CF bonds in fluororubber allows it to form a dense barrier, reducing Cl- concentration. - Permeability coefficient. Polyvinylidene chloride (PVDC) has high crystallinity and tightly packed molecular chains. When blended with fluororubber, it forms a "labyrinth effect," extending the permeability coefficient. - Diffusion pathway, increase Cl - This reduces the difficulty of penetration, achieving the goal of preventing seepage. Nano-montmorillonite can synergistically work with fluororubber to further reduce Cl- content. - Penetration rate.

[0013] The polytetrafluoroethylene nanoparticles in the filler layer primarily fill the micropores on the surface of the aramid fibers, reducing the specific surface area and blocking the capillary permeation of water molecules. Nano-graphene combines with the aramid fibers through π-π stacking to form a conductive network, preventing salt spray adsorption caused by electrostatic accumulation.

[0014] In the elastic buffer layer, the high-saturation nitrile rubber has a low double bond content after hydrogenation, good resistance to damp heat aging, and a high elastic modulus that can absorb most of the stress generated by salt crystallization.

[0015] Modified aramid fibers in the aramid rope core layer can delay fiber hydrolysis and Cl- through modification. - This reduces erosion and improves the salt spray corrosion resistance and service life of aramid fibers.

[0016] Optionally, the modified polyurethane preparation steps are as follows:

[0017] Prepolymer preparation: 50-60% polyester polyol and 15-20% polydimethylsiloxane were vacuum dehydrated at -0.095 MPa and 75-85℃ for 2-3 hours, then cooled to 55-65℃, and 10-15% isophorone diisocyanate and 0.05-0.1% dibutyltin dilaurate were added. The mixture was stirred and reacted under nitrogen protection for 3-4 hours to obtain the prepolymer.

[0018] Prepolymer modification: Cool the prepolymer to 35-45℃, slowly add 3-4% 1,4-butanediol, stir and react for 2-3 hours, add 3-10% tetrahydrofuran to adjust the solid content, then add 3-5% nano-SiO2 and 1-3% perfluorooctyltriethoxysilane, ultrasonically disperse for 30-40 minutes, and continue stirring for 1-2 hours to obtain modified polyurethane.

[0019] In the above technical solution, the Si-O-Si backbone and methyl side chains of polydimethylsiloxane impart extremely low surface energy to the coating, inhibiting the spreading of salt spray droplets. A three-dimensional cross-linked structure is formed through isocyanate curing, blocking Cl... -And the diffusion of water molecules. The short-chain structure of 1,4-butanediol increases the proportion of hard segments and improves tensile strength. By adding SiO2 and perfluorooctyltriethoxysilane, perfluorooctyltriethoxysilane is grafted onto the SiO2 surface through hydrolysis and condensation to form Si-O-Si bonds. The SiO2 modified with perfluorooctyltriethoxysilane has a low surface energy and combines with the polyurethane prepolymer through hydrogen bonds to achieve a hydrophobic effect, making it difficult for salt spray droplets to spread and reducing the risk of corrosion caused by salt crystallization. At the same time, nano-SiO2 acts as a hard filler, improving the hardness and wear resistance of the hydrophobic wear-resistant layer. Modified polyurethane on Cl - Its osmosis acts as a barrier and can also block Cl. - This facilitates the diffusion of water molecules and prevents droplet retention from triggering hydrolysis reactions.

[0020] Optionally, the preparation steps of the modified aramid fiber are as follows:

[0021] Raw material pretreatment: Terephthaloyl chloride, p-phenylenediamine, and bis(trimethoxysilylpropyl)amine were dehydrated under vacuum at -0.095 MPa and 115-125℃ for 4-5 hours;

[0022] Low-temperature solution polycondensation: 35-40% terephthaloyl chloride, 35-40% p-phenylenediamine, 7-9% bis(trimethoxysilylpropyl)amine, 4-6% 4-carboxyphenylboronic acid ester, and 2-4% sulfonated cellulose nanocrystals are dissolved in a mixed solvent of N-methylpyrrolidone and CaCl2 solution at a molar ratio of 2-3:1 at -3 to -5℃. The mixture is ultrasonically treated for 30-40 min, and phosphate buffer is added to maintain the pH at 7.5-8. Then, the mixture is stirred at 190-210 rpm for 8-10 h to generate a prepolymer.

[0023] Dry-jet wet spinning: The spinning solution is extruded and placed into a coagulation bath at 15-25℃ with a mass ratio of water to N-methylpyrrolidone of 6-7:3-4. After preheating and stretching at 240-260℃ with a stretching ratio of 2-3:1, the fiber bundle is heat-treated at 340-360℃ for 30-40 minutes to obtain modified aramid fiber.

[0024] In the above technical solution, terephthaloyl chloride and p-phenylenediamine are the main components of aramid. Terephthaloyl chloride and p-phenylenediamine form a poly(p-phenylenediamine terephthalamide) backbone through low-temperature polycondensation, providing high strength and high modulus. The trimethoxysilane in bis(trimethoxysilylpropyl)amine hydrolyzes to generate Si-OH, which condenses to form a siloxane (Si-O-Si) network. The Si-CH3 groups migrate to the fiber surface, covering the fiber surface, reducing surface energy, and inhibiting water molecule penetration. Dehydrating p-phenylenediamine and bis(trimethoxysilylpropyl)amine can prevent water molecules from undergoing hydrolysis side reactions with terephthaloyl chloride during the polycondensation reaction.

[0025] Low temperatures of -3 to -5°C inhibit the hydrolysis of terephthaloyl chloride, ensuring linear molecular chain growth. The boronic acid ester bond (BO) in 4-carboxyphenylboronic acid esters undergoes reversible breakage and recombination at humidity levels greater than 60%, repairing microcracks. The carboxylic acid group (-COOH) adsorbs Cl- via electrostatic interactions. - This reduces its diffusion rate.

[0026] Sulfonated cellulose nanofibers are prepared from natural cellulose using a strong acid hydrolysis method. The high aspect ratio sulfonated cellulose nanofibers are embedded in an aramid matrix, forming a nano-bridging network that enhances tensile modulus. Surface sulfonic acid groups (-SO3H) adsorb Cl... - This forms an ion barrier.

[0027] N-methylpyrrolidone, as a high-boiling-point polar solvent, ensures the homogeneity of the polycondensation reaction. CaCl2, as an auxiliary agent, can complex free amine groups, preventing premature hydrolysis of terephthaloyl chloride. Phosphate buffer maintains the system pH at 7.5-8, avoiding hydrolysis of borate esters. Solvent diffusion in the coagulation bath induces phase separation, forming a liquid crystal-like oriented structure. Preheating and stretching eliminate internal stress.

[0028] Secondly, the present invention provides a method for preparing an aramid rope conveyor belt, the method comprising the following steps:

[0029] Pretreatment of modified aramid fibers: The modified aramid fibers are treated with plasma at 100-105W for 3-5 minutes in an argon atmosphere;

[0030] Vacuum pressurized filling layer: Nano-graphene is added to polytetrafluoroethylene nano-dispersion, and pretreated modified aramid fibers are vacuumed at -0.095MPa for 10-12min, pressurized at 1.0-1.2MPa for 15-18min, cyclicated 3-4 times, and then cured at 175-185℃ for 10-12min to obtain aramid rope conveyor belt A;

[0031] Spraying barrier layer: Fluororubber and polyvinylidene chloride are dissolved in acetone solution, nano-montmorillonite is added, and ultrasonic dispersion is carried out for 30-40 minutes to obtain the barrier layer. The barrier layer is sprayed under a pressure of 0.5-0.6MPa, pre-cured at 160-170℃ for 5-8 minutes, and then deeply vulcanized at 195-205℃ for 10-12 minutes to obtain aramid rope conveyor belt B.

[0032] Roller-coated hydrophobic and wear-resistant layer: Nano ZnO and titanate coupling agent are premixed and ball-milled for 2-3 hours. Then, modified polyurethane, zinc stearate and defoamer are added in sequence and stirred at 450-550 rpm for 30-40 minutes to obtain a hydrophobic and wear-resistant layer. Roller coating process is used with a coating speed of 5-8 m / min. After standing at 75-85℃ for 2-3 hours, aramid rope conveyor belt C is obtained.

[0033] Elastic buffer layer composite: High-saturation nitrile rubber, carbon black, and plasticizer are mixed at 155-165℃ for 15-20 minutes, vulcanizing agent is added, and mixing is continued for 5-8 minutes to obtain sheet, thus obtaining an elastic buffer layer. The elastic buffer layer is placed on the C surface of the aramid rope conveyor belt, and the molding temperature is 165-175℃, the pressure is 10-12MPa, and the pressure is held for 15-20 minutes to obtain the aramid rope conveyor belt.

[0034] In the above technical solution, the pretreatment step of the modified aramid fiber uses a plasma activation process to bombard the fiber surface, generating etching and free radical active sites (-COOH, -OH), thereby improving the surface energy of the modified aramid fiber and enhancing the adhesion of the coating.

[0035] In the vacuum pressurization filling layer step, vacuuming removes air from the fiber micropores, creating negative pressure channels. Pressurization forces the polytetrafluoroethylene (PTFE) nano-dispersion and graphene nanoparticles to penetrate the fiber micropores. Curing at 180°C causes the PTFE nanoparticles to melt and form a continuous film, while the graphene bonds with the aramid fibers via π-π bonds, constructing a conductive network.

[0036] In the barrier layer spraying step, the high volatility of acetone ensures rapid film formation, resulting in a uniformly dispersed composite structure. Pre-curing at 160℃ promotes the entanglement of fluororubber and polyvinylidene chloride molecular chains, forming preliminary cross-linking. Deep vulcanization at 200℃ activates the CF bond stabilization in the fluororubber peroxide vulcanization system, increasing crystallinity to 55%.

[0037] In the roll-coating process for the hydrophobic and wear-resistant layer, perfluorosilanes are grafted onto the SiO2 surface via hydrolysis and condensation to form Si-O-Si bonds. The perfluorosilane-modified SiO2 has low surface energy and simultaneously bonds with the organosilicon-modified polyurethane prepolymer through hydrogen bonds, achieving a hydrophobic effect. The isocyanate groups react with the -OH groups in the organosilicon-modified polyurethane prepolymer to form a three-dimensional cross-linked network, enhancing wear resistance.

[0038] In the elastic buffer layer composite step, the silanol groups in carbon black interact with the polar groups of HNBR to form a "bonded rubber" structure, thereby improving tensile strength. Peroxides act as vulcanizing agents, generating free radicals to initiate crosslinking of the highly saturated nitrile rubber.

[0039] Thirdly, the present invention provides an aramid rope conveyor belt and a process for preparing the aramid rope conveyor belt, and the high-strength gas-shielded welding wire prepared by the process is used in ports and in high-humidity and high-salt-spray environments.

[0040] In summary, the present invention has at least one of the following beneficial technical effects:

[0041] 1. In the hydrophobic wear-resistant layer of the present invention, the modified polyurethane reduces surface energy, inhibits the spreading of salt spray droplets, and reduces the risk of corrosion caused by salt crystallization, thus protecting Cl...- The osmosis of Cl also acts as a barrier, blocking its penetration. - This facilitates the diffusion of water molecules, preventing droplet retention and hydrolysis. Nano-ZnO, as a hard filler, enhances the coating's wear resistance. The alkoxy group at one end of the titanate coupling agent reacts with the hydroxyl groups on the ZnO surface. Surface treatment with the titanate coupling agent improves the dispersibility of ZnO in the modified polyurethane. The other end binds to the polar groups of the modified polyurethane, increasing the filler-matrix interface strength and preventing agglomeration. Zinc stearate long-chain alkyl (C...) 18 H 35 Defoamers can reduce the surface energy of the coating. They can also reduce the surface tension of the coating slurry and break up bubbles generated during mixing and coating.

[0042] 2. In the barrier layer of this invention, the fluororubber CF bond has high bond energy, which can form a dense barrier and reduce Cl. - Permeability coefficient. Polyvinylidene chloride (PVDC) has high crystallinity and tightly packed molecular chains. When blended with fluororubber, it forms a "labyrinth effect," extending the permeability coefficient. - Diffusion pathway, increase Cl - This reduces the difficulty of penetration, achieving the goal of preventing seepage. Nano-montmorillonite can synergistically work with fluororubber to further reduce Cl- content. - Penetration rate.

[0043] 3. In the filler layer of this invention, polytetrafluoroethylene nanoparticles mainly fill the micropores on the surface of aramid fibers, reducing the specific surface area and blocking the capillary permeation of water molecules. Nano-graphene combines with aramid fibers through π-π stacking to form a conductive network, avoiding salt spray adsorption caused by electrostatic accumulation.

[0044] 4. In the elastic buffer layer of the present invention, the high-saturation nitrile rubber has a low double bond content after hydrogenation, good resistance to damp heat aging, and a high elastic modulus that can absorb most of the stress generated by salt crystallization.

[0045] 5. The modified aramid fibers in the aramid rope core layer of the present invention can delay fiber hydrolysis and Cl- through modification. - This reduces erosion and improves the salt spray corrosion resistance and service life of aramid fibers. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to the embodiments.

[0047] All materials used in the following examples are available for purchase on the market.

[0048] Example 1: This example discloses an aramid rope conveyor belt and its preparation method.

[0049] The aramid rope conveyor belt comprises, from the outside to the inside: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 5:14:1.

[0050] The aramid rope core layer comprises modified aramid fibers.

[0051] The elastic buffer layer comprises 95 parts high-saturation nitrile rubber, 25 parts carbon black, 2 parts dicumyl peroxide, and 1 part dioctyl terephthalate.

[0052] The composite coating comprises, from the outside to the inside, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer. The thickness ratio of the hydrophobic wear-resistant layer, the barrier layer, and the filler layer is 1:2:1. The hydrophobic wear-resistant layer comprises 85% modified polyurethane, 5% nano-ZnO, 5% zinc stearate, 3% titanate coupling agent, and 2% defoamer YRXP-0901. The barrier layer comprises 66% fluororubber, 30% polyvinylidene chloride, and 4% nano-montmorillonite. The filler layer comprises 93% polytetrafluoroethylene nano-dispersion, 4% nano-graphene, and 3% KH550 coupling agent.

[0053] The preparation steps of the modified polyurethane are as follows: Polyester diol and trimethylolpropane are mixed and stirred at a mass ratio of 250:1 to form mixture A. The mixture is heated to 70°C, and then 1,6-hexamethylene diisocyanate at a mass ratio of 1:5.5 to mixture A is added to obtain mixture B. The mixture is heated to 75°C, and acetone at a mass ratio of 1:1.8 to mixture B is added to dilute it to obtain mixed solution C. The mixture is then cooled to 41.5°C. Sodium salts of 1,2-ethylenediamine and ethylenediamine-2-ethylsulfonic acid at a mass ratio of 1:2.6 are dissolved in distilled water and added to mixed solution C within 30 seconds. After 15 minutes, distilled water is added, and then acetone is distilled off under reduced pressure to obtain the modified polyurethane.

[0054] The preparation steps of the modified aramid fiber are as follows: First, the aramid fiber is soaked in deionized water and bathed in a 50°C water bath for 6 hours. Then, the fiber is soaked in ethanol and bathed in a 50°C water bath for 6 hours. After that, it is dried in a 60°C drying oven. Sodium hydride powder with a mass ratio of 0.6:1 to the treated fiber is added to dimethyl sulfoxide and stirred evenly at room temperature on a magnetic stirrer. Then, the treated fiber is added to the mixed solution and stirred to allow the fiber to react fully with the solution for 20 minutes. After that, the fiber is taken out and stored under N2 protection. Triisopropylchlorosilane is added to dimethyl sulfoxide at a volume ratio of 3:20 and stirred to mix evenly. The treated fiber is added to the mixed solution, sealed, stirred for 10 minutes, and bathed in a 60°C water bath for 12 hours. The obtained fiber is washed multiple times with deionized water and then dried in a drying oven at 60°C to obtain the modified aramid fiber.

[0055] The method for preparing the aramid rope conveyor belt includes the following steps:

[0056] S1. Pretreatment of modified aramid fibers: The modified aramid fibers are treated with 100W plasma for 5 minutes in an argon atmosphere.

[0057] S2, Vacuum-pressurized filling layer: Add nano-graphene to polytetrafluoroethylene nano-dispersion, and vacuum the pretreated modified aramid fiber at -0.095MPa for 10min, pressurize it at 1.2MPa for 15min, repeat 3 times, and then cure it at 180℃ for 10min to obtain aramid rope conveyor belt A.

[0058] S3. Spraying the barrier layer: Dissolve fluororubber and polyvinylidene chloride in acetone solution, add nano montmorillonite, and ultrasonically disperse for 35 minutes to obtain the barrier layer. Spray it under a pressure of 0.5 MPa, pre-cur it at 165℃ for 6 minutes, and then deeply vulcanize it at 200℃ for 10 minutes to obtain aramid rope conveyor belt B.

[0059] S4. Roller-coated hydrophobic and wear-resistant layer: Nano ZnO and titanate coupling agent are premixed and ball-milled for 2.5 hours. Then, modified polyurethane, zinc stearate, and defoamer YRXP-0901 are added sequentially and stirred at 500 rpm for 35 minutes to obtain a hydrophobic and wear-resistant layer. The coating process is adopted with a roller coating speed of 6 m / min and left to stand at 80℃ for 2.5 hours to obtain aramid rope conveyor belt C.

[0060] S5, Elastic Buffer Layer Composite: High-saturation nitrile rubber, carbon black, and dioctyl terephthalate are mixed at 160℃ for 15 minutes, dicumyl peroxide is added, and mixing is continued for 5 minutes to obtain a sheet, which is then placed on the surface of aramid rope conveyor belt C. The molding temperature is 170℃, the pressure is 12MPa, and the pressure is held for 15 minutes to obtain aramid rope conveyor belt #1.

[0061] Example 2: This example discloses an aramid rope conveyor belt and its preparation method.

[0062] By mass fraction, the aramid rope conveyor belt comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 3:9:1.

[0063] The aramid rope core layer comprises modified aramid fibers.

[0064] Based on the mass fractions of the elastic buffer layer, the elastic buffer layer comprises 105 parts high-saturation nitrile rubber, 35 parts carbon black, 4 parts dicumyl peroxide, and 3 parts dioctyl terephthalate.

[0065] The composite coating comprises, from the outside to the inside, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer. The thickness ratio of the hydrophobic wear-resistant layer, the barrier layer, and the filler layer is 1:1:1. The hydrophobic wear-resistant layer comprises 90% modified polyurethane, 3% nano-ZnO, 3% zinc stearate, 2% titanate coupling agent, and 2% defoamer YRXP-0901. The barrier layer comprises 70% fluororubber, 28% polyvinylidene chloride, and 2% nano-montmorillonite. The filler layer comprises 97% polytetrafluoroethylene nano-dispersion, 2% nano-graphene, and 1% KH550 coupling agent.

[0066] The rest is the same as in Example 1.

[0067] Example 3: This example discloses an aramid rope conveyor belt and its preparation method.

[0068] The aramid rope conveyor belt comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 4:11:1.

[0069] The aramid rope core layer comprises modified aramid fibers.

[0070] The elastic buffer layer comprises 100 parts high-saturation nitrile rubber, 30 parts carbon black, 3 parts dicumyl peroxide, and 2 parts dioctyl terephthalate.

[0071] The composite coating comprises, from the outside to the inside, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer. The thickness ratio of the hydrophobic wear-resistant layer, the barrier layer, and the filler layer is 1:1.5:1. The hydrophobic wear-resistant layer comprises 88% modified polyurethane, 5% nano ZnO, 3% zinc stearate, 3% titanate coupling agent, and 1% defoamer YRXP-0901. The barrier layer comprises 68% fluororubber, 29% polyvinylidene chloride, and 3% nano montmorillonite. The filler layer comprises 95% polytetrafluoroethylene nano-dispersion, 3% nano graphene, and 2% KH550 coupling agent.

[0072] The rest is the same as in Example 1.

[0073] Example 4: This example discloses an aramid rope conveyor belt and its preparation method.

[0074] The aramid rope conveyor belt comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 4:11:1.

[0075] The aramid rope core layer comprises modified aramid fibers.

[0076] The elastic buffer layer comprises 100 parts high-saturation nitrile rubber, 30 parts carbon black, 3 parts dicumyl peroxide, and 2 parts dioctyl terephthalate.

[0077] The composite coating comprises, from the outside to the inside, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer. The thickness ratio of the hydrophobic wear-resistant layer, the barrier layer, and the filler layer is 1:1.5:1. The hydrophobic wear-resistant layer comprises 88% modified polyurethane, 5% nano ZnO, 3% zinc stearate, 3% titanate coupling agent, and 1% defoamer YRXP-0901. The barrier layer comprises 68% fluororubber, 29% polyvinylidene chloride, and 3% nano montmorillonite. The filler layer comprises 95% polytetrafluoroethylene nano-dispersion, 3% nano graphene, and 2% KH550 coupling agent.

[0078] The preparation steps of the modified aramid fiber are as follows: First, the aramid fiber is soaked in deionized water and bathed in a 50°C water bath for 6 hours. Then, the fiber is soaked in ethanol and bathed in a 50°C water bath for 6 hours. After that, it is dried in a 60°C drying oven. Sodium hydride powder with a mass ratio of 0.6:1 to the treated fiber is added to dimethyl sulfoxide and stirred evenly at room temperature on a magnetic stirrer. Then, the treated fiber is added to the mixed solution and stirred to allow the fiber to react fully with the solution for 20 minutes. After that, the fiber is taken out and stored under N2 protection. Triisopropylchlorosilane is added to dimethyl sulfoxide at a volume ratio of 3:20 and stirred to mix evenly. The treated fiber is added to the mixed solution, sealed, stirred for 10 minutes, and bathed in a 60°C water bath for 12 hours. The obtained fiber is washed multiple times with deionized water and then dried in a drying oven at 60°C to obtain the modified aramid fiber.

[0079] The method for preparing the aramid rope conveyor belt includes the following steps:

[0080] S1. Pretreatment of modified aramid fibers: The modified aramid fibers are treated with 100W plasma for 5 minutes in an argon atmosphere.

[0081] S2, Vacuum-pressurized filling layer: Add nano-graphene to polytetrafluoroethylene nano-dispersion, and vacuum the pretreated modified aramid fiber at -0.095MPa for 10min, pressurize it at 1.2MPa for 15min, repeat 3 times, and then cure it at 180℃ for 10min to obtain aramid rope conveyor belt A.

[0082] S3. Spraying the barrier layer: Dissolve fluororubber and polyvinylidene chloride in acetone solution, add nano montmorillonite, and ultrasonically disperse for 35 minutes to obtain the barrier layer. Spray it under a pressure of 0.5 MPa, pre-cur it at 165℃ for 6 minutes, and then deeply vulcanize it at 200℃ for 10 minutes to obtain aramid rope conveyor belt B.

[0083] S4. Preparation of modified polyurethane:

[0084] S41. Preparation of prepolymer: 55% polyester polyol and 18% polydimethylsiloxane were vacuum dehydrated at -0.095 MPa and 80°C for 2 hours, then cooled to 60°C, and 12% isophorone diisocyanate and 0.1% dibutyltin dilaurate were added. The mixture was stirred and reacted under nitrogen protection for 3 hours to obtain the prepolymer.

[0085] S42. Prepolymer modification: Cool the prepolymer to 40℃, slowly add 3% 1,4-butanediol, stir and react for 2h, add 7% tetrahydrofuran to adjust the solid content, then add 4% nano SiO2 and 2% perfluorooctyltriethoxysilane, ultrasonically disperse for 30min, and continue stirring for 1.5h to obtain modified polyurethane.

[0086] S5. Roller-coated hydrophobic and wear-resistant layer: Nano ZnO and titanate coupling agent are premixed and ball-milled for 2.5 hours. Then, modified polyurethane, zinc stearate, and defoamer YRXP-0901 are added sequentially and stirred at 500 rpm for 35 minutes to obtain a hydrophobic and wear-resistant layer. The coating process is adopted with a roller coating speed of 6 m / min and left to stand at 80℃ for 2.5 hours to obtain aramid rope conveyor belt C.

[0087] S6, Elastic Buffer Layer Composite: High-saturation nitrile rubber, carbon black, and dioctyl terephthalate are mixed at 160℃ for 15 minutes, dicumyl peroxide is added, and mixing is continued for 5 minutes to obtain a sheet, which is then placed on the surface of aramid rope conveyor belt C. The molding temperature is 170℃, the pressure is 12MPa, and the pressure is held for 15 minutes to obtain aramid rope conveyor belt #4.

[0088] Example 5: This example discloses an aramid rope conveyor belt and its preparation method.

[0089] The aramid rope conveyor belt comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 4:11:1.

[0090] The aramid rope core layer comprises modified aramid fibers.

[0091] The elastic buffer layer comprises 100 parts high-saturation nitrile rubber, 30 parts carbon black, 3 parts dicumyl peroxide, and 2 parts dioctyl terephthalate.

[0092] The composite coating comprises, from the outside to the inside, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer. The thickness ratio of the hydrophobic wear-resistant layer, the barrier layer, and the filler layer is 1:1.5:1. The hydrophobic wear-resistant layer comprises 88% modified polyurethane, 5% nano ZnO, 3% zinc stearate, 3% titanate coupling agent, and 1% defoamer YRXP-0901. The barrier layer comprises 68% fluororubber, 29% polyvinylidene chloride, and 3% nano montmorillonite. The filler layer comprises 95% polytetrafluoroethylene nano-dispersion, 3% nano graphene, and 2% KH550 coupling agent.

[0093] The preparation steps of the modified polyurethane are as follows: Polyester diol and trimethylolpropane are mixed and stirred at a mass ratio of 250:1 to form mixture A. The mixture is heated to 70°C, and then 1,6-hexamethylene diisocyanate at a mass ratio of 1:5.5 to mixture A is added to obtain mixture B. The mixture is heated to 75°C, and acetone at a mass ratio of 1:1.8 to mixture B is added to dilute it to obtain mixed solution C. The mixture is then cooled to 41.5°C. Sodium salts of 1,2-ethylenediamine and ethylenediamine-2-ethylsulfonic acid at a mass ratio of 1:2.6 are dissolved in distilled water and added to mixed solution C within 30 seconds. After 15 minutes, distilled water is added, and then acetone is distilled off under reduced pressure to obtain the modified polyurethane.

[0094] The method for preparing the aramid rope conveyor belt includes the following steps:

[0095] S1. Preparation of modified aramid fibers:

[0096] S11. Raw material pretreatment: Terephthaloyl chloride, p-phenylenediamine, and bis(trimethoxysilylpropyl)amine were vacuum dehydrated for 4 hours at -0.095 MPa and 120°C. Sulfonated cellulose nanocrystals were added to N-methylpyrrolidone solvent and ultrasonically treated for 30 minutes to form a uniform dispersion.

[0097] S12. Low-temperature solution polycondensation: 40% terephthaloyl chloride, 40% p-phenylenediamine, 8% bis(trimethoxysilylpropyl)amine, 5% 4-carboxyphenylboronic acid ester, and 3% sulfonated nanocellulose whiskers were dissolved in a mixed solvent of N-methylpyrrolidone and CaCl2 solution at a molar ratio of 2.5:1 at -5℃. The mixture was ultrasonically treated for 35 min, and phosphate buffer was added to maintain the pH at 7.5-8. Then, the mixture was stirred at 200 rpm for 9 h to generate a prepolymer.

[0098] S13. Dry-jet wet spinning: The spinning solution is extruded and placed into a coagulation bath at 15-25℃ with a mass ratio of water to N-methylpyrrolidone of 7:3. After preheating and stretching at 250℃ with a stretching ratio of 2:1, the fiber bundle is heat-treated at 350℃ for 35 minutes to obtain modified aramid fiber.

[0099] S2. Pretreatment of modified aramid fibers: The modified aramid fibers are treated with 100W plasma for 5 minutes in an argon atmosphere.

[0100] S3, Vacuum-pressurized filling layer: Add nano-graphene to polytetrafluoroethylene nano-dispersion, and vacuum the pretreated modified aramid fiber at -0.095MPa for 10min, pressurize it at 1.2MPa for 15min, repeat 3 times, and then cure it at 180℃ for 10min to obtain aramid rope conveyor belt A.

[0101] S4. Spraying the barrier layer: Dissolve fluororubber and polyvinylidene chloride in acetone solution, add nano montmorillonite, and ultrasonically disperse for 35 minutes to obtain the barrier layer. Spray it under a pressure of 0.5 MPa, pre-cur it at 165℃ for 6 minutes, and then deeply vulcanize it at 200℃ for 10 minutes to obtain aramid rope conveyor belt B.

[0102] S5. Roller-coated hydrophobic and wear-resistant layer: Nano ZnO and titanate coupling agent are premixed and ball-milled for 2.5 hours. Then, modified polyurethane, zinc stearate, and defoamer YRXP-0901 are added sequentially and stirred at 500 rpm for 35 minutes to obtain a hydrophobic and wear-resistant layer. The coating process is adopted with a roller coating speed of 6 m / min and left to stand at 80℃ for 2.5 hours to obtain aramid rope conveyor belt C.

[0103] S6, Elastic Buffer Layer Composite: High-saturation nitrile rubber, carbon black, and dioctyl terephthalate are mixed at 160℃ for 15 minutes, dicumyl peroxide is added, and mixing is continued for 5 minutes to obtain a sheet, which is then placed on the surface of aramid rope conveyor belt C. The molding temperature is 170℃, the pressure is 12MPa, and the pressure is held for 15 minutes to obtain aramid rope conveyor belt #5.

[0104] Example 6: This example discloses an aramid rope conveyor belt and its preparation method.

[0105] The aramid rope conveyor belt comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 4:11:1.

[0106] The aramid rope core layer comprises modified aramid fibers.

[0107] The elastic buffer layer comprises 100 parts high-saturation nitrile rubber, 30 parts carbon black, 3 parts dicumyl peroxide, and 2 parts dioctyl terephthalate.

[0108] The composite coating comprises, from the outside to the inside, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer. The thickness ratio of the hydrophobic wear-resistant layer, the barrier layer, and the filler layer is 1:1.5:1. The hydrophobic wear-resistant layer comprises 88% modified polyurethane, 5% nano ZnO, 3% zinc stearate, 3% titanate coupling agent, and 1% defoamer YRXP-0901. The barrier layer comprises 68% fluororubber, 29% polyvinylidene chloride, and 3% nano montmorillonite. The filler layer comprises 95% polytetrafluoroethylene nano-dispersion, 3% nano graphene, and 2% KH550 coupling agent.

[0109] The method for preparing the aramid rope conveyor belt includes the following steps:

[0110] S1. Preparation of modified aramid fibers:

[0111] S11. Raw material pretreatment: Terephthaloyl chloride, p-phenylenediamine, and bis(trimethoxysilylpropyl)amine were vacuum dehydrated for 4 hours at -0.095 MPa and 120°C. Sulfonated cellulose nanocrystals were added to N-methylpyrrolidone solvent and ultrasonically treated for 30 minutes to form a uniform dispersion.

[0112] S12. Low-temperature solution polycondensation: 40% terephthaloyl chloride, 40% p-phenylenediamine, 8% bis(trimethoxysilylpropyl)amine, 5% 4-carboxyphenylboronic acid ester, and 3% sulfonated nanocellulose whiskers were dissolved in a mixed solvent of N-methylpyrrolidone and CaCl2 solution at a molar ratio of 2.5:1 at -5℃. The mixture was ultrasonically treated for 35 min, and phosphate buffer was added to maintain the pH at 7.5-8. Then, the mixture was stirred at 200 rpm for 9 h to generate a prepolymer.

[0113] S13. Dry-jet wet spinning: The spinning solution is extruded and placed into a coagulation bath at 15-25℃ with a water and N-methylpyrrolidone mass ratio of 7:3. After preheating and stretching at 250℃ with a stretching ratio of 2:1, the fiber bundle is heat-treated at 350℃ for 35 minutes to obtain modified aramid fiber.

[0114] S2. Pretreatment of modified aramid fibers: The modified aramid fibers are treated with 100W plasma for 5 minutes in an argon atmosphere.

[0115] S3, Vacuum-pressurized filling layer: Add nano-graphene to polytetrafluoroethylene nano-dispersion, and vacuum the pretreated modified aramid fiber at -0.095MPa for 10min, pressurize it at 1.2MPa for 15min, repeat 3 times, and then cure it at 180℃ for 10min to obtain aramid rope conveyor belt A.

[0116] S4. Spraying the barrier layer: Dissolve fluororubber and polyvinylidene chloride in acetone solution, add nano montmorillonite, and ultrasonically disperse for 35 minutes to obtain the barrier layer. Spray it under a pressure of 0.5 MPa, pre-cur it at 165℃ for 6 minutes, and then deeply vulcanize it at 200℃ for 10 minutes to obtain aramid rope conveyor belt B.

[0117] S5. Preparation of modified polyurethane:

[0118] S51. Preparation of prepolymer: 55% polyester polyol and 18% polydimethylsiloxane were vacuum dehydrated at -0.095MPa and 80℃ for 2 hours, cooled to 60℃, and 12% isophorone diisocyanate and 0.1% dibutyltin dilaurate were added. The mixture was stirred and reacted under nitrogen protection for 3 hours to obtain the prepolymer.

[0119] S52. Prepolymer modification: Cool the prepolymer to 40℃, slowly add 3% 1,4-butanediol, stir and react for 2h, add 7% tetrahydrofuran to adjust the solid content, then add 4% nano SiO2 and 2% perfluorooctyltriethoxysilane, ultrasonically disperse for 30min, and continue stirring for 1.5h to obtain modified polyurethane.

[0120] S6. Roller-coated hydrophobic and wear-resistant layer: Nano ZnO and titanate coupling agent are premixed and ball-milled for 2.5 hours. Then, modified polyurethane, zinc stearate, and defoamer YRXP-0901 are added sequentially and stirred at 500 rpm for 35 minutes to obtain a hydrophobic and wear-resistant layer. The coating process is adopted with a roller coating speed of 6 m / min and left to stand at 80℃ for 2.5 hours to obtain aramid rope conveyor belt C.

[0121] S7, Elastic Buffer Layer Composite: High-saturation nitrile rubber, carbon black, and dioctyl terephthalate are mixed at 160℃ for 15 minutes, dicumyl peroxide is added, and mixing is continued for 5 minutes to obtain a sheet, which is then placed on the surface of aramid rope conveyor belt C. The molding temperature is 170℃, the pressure is 12MPa, and the pressure is held for 15 minutes to obtain aramid rope conveyor belt #6.

[0122] Comparative Example 1: This comparative example provides a comparative aramid rope conveyor belt and its preparation method. The comparative aramid rope conveyor belt includes: an aramid rope core layer and an elastic buffer layer. The thickness ratio of the aramid rope core layer and the elastic buffer layer is 4:1.

[0123] The aramid rope core layer comprises modified aramid fibers.

[0124] Based on the mass fraction of the elastic buffer layer, the elastic buffer layer comprises 100 parts of highly saturated nitrile rubber, 30 parts of carbon black, 3 parts of dicumyl peroxide, and 2 parts of dioctyl terephthalate.

[0125] The method for preparing the aramid rope conveyor belt includes the following steps:

[0126] S1. Preparation of modified aramid fibers:

[0127] S11. Raw material pretreatment: Terephthaloyl chloride, p-phenylenediamine, and bis(trimethoxysilylpropyl)amine were vacuum dehydrated for 4 hours at -0.095 MPa and 120°C. Sulfonated cellulose nanocrystals were added to N-methylpyrrolidone solvent and ultrasonically treated for 30 minutes to form a uniform dispersion.

[0128] S12. Low-temperature solution polycondensation: 40% terephthaloyl chloride, 40% p-phenylenediamine, 8% bis(trimethoxysilylpropyl)amine, 5% 4-carboxyphenylboronic acid ester, and 3% sulfonated nanocellulose whiskers were dissolved in a mixed solvent of N-methylpyrrolidone and CaCl2 solution at a molar ratio of 2.5:1 at -5℃. The mixture was ultrasonically treated for 35 min, and phosphate buffer was added to maintain the pH at 7.5-8. Then, the mixture was stirred at 200 rpm for 9 h to generate a prepolymer.

[0129] S13. Dry-jet wet spinning: The spinning solution is extruded and placed into a coagulation bath at 15-25℃ with a mass ratio of water to N-methylpyrrolidone of 7:3. After preheating and stretching at 250℃ with a stretching ratio of 2:1, the fiber bundle is heat-treated at 350℃ for 35 minutes to obtain modified aramid fiber.

[0130] S2. Pretreatment of modified aramid fibers: The modified aramid fibers are treated with 100W plasma for 5 minutes in an argon atmosphere.

[0131] S3, Elastic Buffer Layer Composite: High-saturation nitrile rubber, carbon black, and dioctyl terephthalate are mixed at 160℃ for 15 minutes, dicumyl peroxide is added, and the mixture is further mixed for 5 minutes to obtain a sheet, which is then placed on the surface of the aramid rope conveyor belt C. The molding temperature is 170℃, the pressure is 12MPa, and the pressure is held for 15 minutes to obtain the comparative aramid rope conveyor belt D1.

[0132] Comparative Example 2: This comparative example provides a comparative aramid rope conveyor belt and its preparation method.

[0133] The aramid rope conveyor belt comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 4:11:1.

[0134] The aramid rope core layer comprises modified aramid fibers.

[0135] The elastic buffer layer comprises 100 parts high-saturation nitrile rubber, 30 parts carbon black, 3 parts dicumyl peroxide, and 2 parts dioctyl terephthalate.

[0136] The composite coating comprises a barrier layer and a filler layer from the outside to the inside. The thickness ratio of the barrier layer to the filler layer is 1.2:1. The barrier layer comprises 68% fluororubber, 29% polyvinylidene chloride, and 3% nano-montmorillonite. The filler layer comprises 95% polytetrafluoroethylene nano-dispersion, 3% nano-graphene, and 2% KH550 coupling agent.

[0137] S1. Preparation of modified aramid fibers:

[0138] S11. Raw material pretreatment: Terephthaloyl chloride, p-phenylenediamine, and bis(trimethoxysilylpropyl)amine were vacuum dehydrated for 4 hours at -0.095 MPa and 120°C. Sulfonated cellulose nanocrystals were added to N-methylpyrrolidone solvent and ultrasonically treated for 30 minutes to form a uniform dispersion.

[0139] S12. Low-temperature solution polycondensation: 40% terephthaloyl chloride, 40% p-phenylenediamine, 8% bis(trimethoxysilylpropyl)amine, 5% 4-carboxyphenylboronic acid ester, and 3% sulfonated nanocellulose whiskers were dissolved in a mixed solvent of N-methylpyrrolidone and CaCl2 solution at a molar ratio of 2.5:1 at -5℃. The mixture was ultrasonically treated for 35 min, and phosphate buffer was added to maintain the pH at 7.5-8. Then, the mixture was stirred at 200 rpm for 9 h to generate a prepolymer.

[0140] S13. Dry-jet wet spinning: The spinning solution is extruded and placed into a coagulation bath at 15-25℃ with a mass ratio of water to N-methylpyrrolidone of 7:3. After preheating and stretching at 250℃ with a stretching ratio of 2:1, the fiber bundle is heat-treated at 350℃ for 35 minutes to obtain modified aramid fiber.

[0141] S2. Pretreatment of modified aramid fibers: The modified aramid fibers are treated with 100W plasma for 5 minutes in an argon atmosphere.

[0142] S3, Vacuum-pressurized filling layer: Add nano-graphene to polytetrafluoroethylene nano-dispersion, and vacuum the pretreated modified aramid fiber at -0.095MPa for 10min, pressurize it at 1.2MPa for 15min, repeat 3 times, and then cure it at 180℃ for 10min to obtain aramid rope conveyor belt A.

[0143] S4. Spraying the barrier layer: Dissolve fluororubber and polyvinylidene chloride in acetone solution, add nano montmorillonite, and ultrasonically disperse for 35 minutes to obtain the barrier layer. Spray it under a pressure of 0.5 MPa, pre-cur it at 165℃ for 6 minutes, and then deeply vulcanize it at 200℃ for 10 minutes to obtain aramid rope conveyor belt B.

[0144] S5, Elastic Buffer Layer Composite: High-saturation nitrile rubber, carbon black, and dioctyl terephthalate are mixed at 160℃ for 15 minutes, dicumyl peroxide is added, and mixing is continued for 5 minutes to obtain a sheet, which is then placed on the surface of aramid rope conveyor belt B. The molding temperature is 170℃, the pressure is 12MPa, and the pressure is held for 15 minutes to obtain the comparative aramid rope conveyor belt D2.

[0145] Comparative Example 3: This comparative example provides a comparative aramid rope conveyor belt and its preparation method.

[0146] The aramid rope conveyor belt comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 4:11:1.

[0147] The aramid rope core layer comprises modified aramid fibers.

[0148] The elastic buffer layer comprises 100 parts high-saturation nitrile rubber, 30 parts carbon black, 3 parts dicumyl peroxide, and 2 parts dioctyl terephthalate.

[0149] The composite coating comprises a hydrophobic wear-resistant layer and a filler layer from the outside to the inside. The thickness ratio of the hydrophobic wear-resistant layer to the barrier layer is 1:1. The hydrophobic wear-resistant layer comprises 88% modified polyurethane, 5% nano ZnO, 3% zinc stearate, 3% titanate coupling agent, and 1% defoamer YRXP-0901. The filler layer comprises 95% polytetrafluoroethylene nano-dispersion, 3% nano graphene, and 2% KH550 coupling agent.

[0150] The method for preparing the aramid rope conveyor belt includes the following steps:

[0151] S1. Preparation of modified aramid fibers:

[0152] S11. Raw material pretreatment: Terephthaloyl chloride, p-phenylenediamine, and bis(trimethoxysilylpropyl)amine were vacuum dehydrated for 4 hours at -0.095 MPa and 120°C. Sulfonated cellulose nanocrystals were added to N-methylpyrrolidone solvent and ultrasonically treated for 30 minutes to form a uniform dispersion.

[0153] S12. Low-temperature solution polycondensation: 40% terephthaloyl chloride, 40% p-phenylenediamine, 8% bis(trimethoxysilylpropyl)amine, 5% 4-carboxyphenylboronic acid ester, and 3% sulfonated nanocellulose whiskers were dissolved in a mixed solvent of N-methylpyrrolidone and CaCl2 solution at a molar ratio of 2.5:1 at -5℃. The mixture was ultrasonically treated for 35 min, and phosphate buffer was added to maintain the pH at 7.5-8. Then, the mixture was stirred at 200 rpm for 9 h to generate a prepolymer.

[0154] S13. Dry-jet wet spinning: The spinning solution is extruded and placed into a coagulation bath at 15-25℃ with a water and N-methylpyrrolidone mass ratio of 7:3. After preheating and stretching at 250℃ with a stretching ratio of 2:1, the fiber bundle is heat-treated at 350℃ for 35 minutes to obtain modified aramid fiber.

[0155] S2. Pretreatment of modified aramid fibers: The modified aramid fibers are treated with 100W plasma for 5 minutes in an argon atmosphere.

[0156] S3, Vacuum-pressurized filling layer: Add nano-graphene to polytetrafluoroethylene nano-dispersion, and vacuum the pretreated modified aramid fiber at -0.095MPa for 10min, pressurize it at 1.2MPa for 15min, repeat 3 times, and then cure it at 180℃ for 10min to obtain aramid rope conveyor belt A.

[0157] S4. Preparation of modified polyurethane:

[0158] S41. Preparation of prepolymer: 55% polyester polyol and 18% polydimethylsiloxane were vacuum dehydrated at -0.095 MPa and 80°C for 2 hours, then cooled to 60°C, and 12% isophorone diisocyanate and 0.1% dibutyltin dilaurate were added. The mixture was stirred and reacted under nitrogen protection for 3 hours to obtain the prepolymer.

[0159] S42. Prepolymer modification: Cool the prepolymer to 40℃, slowly add 3% 1,4-butanediol, stir and react for 2h, add 7% tetrahydrofuran to adjust the solid content, then add 4% nano SiO2 and 2% perfluorooctyltriethoxysilane, ultrasonically disperse for 30min, and continue stirring for 1.5h to obtain modified polyurethane.

[0160] S5. Roller-coated hydrophobic and wear-resistant layer: Nano ZnO and titanate coupling agent are premixed and ball-milled for 2.5 h. Then, modified polyurethane, zinc stearate, and defoamer YRXP-0901 are added in sequence and stirred at 500 rpm for 35 min to obtain a hydrophobic and wear-resistant layer. Roller coating process is used with a coating speed of 6 m / min and a wet film thickness of 70 μm. After standing at 80℃ for 2.5 h, aramid rope conveyor belt C is obtained.

[0161] S6, Elastic Buffer Layer Composite: High-saturation nitrile rubber, carbon black, and dioctyl terephthalate are mixed at 160℃ for 15 minutes, dicumyl peroxide is added, and mixing is continued for 5 minutes to obtain a sheet, which is then placed on the surface of aramid rope conveyor belt C. The molding temperature is 170℃, the pressure is 12MPa, and the pressure is held for 15 minutes to obtain the comparative aramid rope conveyor belt D3.

[0162] Comparative Example 4: This comparative example provides a comparative aramid rope conveyor belt and its preparation method:

[0163] The aramid rope conveyor belt comprises: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 4:11:1.

[0164] The aramid rope core layer comprises modified aramid fibers.

[0165] The elastic buffer layer comprises 100 parts high-saturation nitrile rubber, 30 parts carbon black, 3 parts dicumyl peroxide, and 2 parts dioctyl terephthalate.

[0166] The composite coating comprises a hydrophobic wear-resistant layer and a barrier layer from the outside to the inside. The thickness ratio of the hydrophobic wear-resistant layer to the barrier layer is 1:1.2. The hydrophobic wear-resistant layer comprises 88% modified polyurethane, 5% nano ZnO, 3% zinc stearate, 3% titanate coupling agent, and 1% defoamer YRXP-0901. The barrier layer comprises 68% fluororubber, 29% polyvinylidene chloride, and 3% nano montmorillonite.

[0167] The method for preparing the aramid rope conveyor belt includes the following steps:

[0168] S1. Preparation of modified aramid fibers:

[0169] S11. Raw material pretreatment: Terephthaloyl chloride, p-phenylenediamine, and bis(trimethoxysilylpropyl)amine were vacuum dehydrated for 4 hours at -0.095 MPa and 120°C. Sulfonated cellulose nanocrystals were added to N-methylpyrrolidone solvent and ultrasonically treated for 30 minutes to form a uniform dispersion.

[0170] S12. Low-temperature solution polycondensation: 40% terephthaloyl chloride, 40% p-phenylenediamine, 8% bis(trimethoxysilylpropyl)amine, 5% 4-carboxyphenylboronic acid ester, and 3% sulfonated nanocellulose whiskers were dissolved in a mixed solvent of N-methylpyrrolidone and CaCl2 solution at a molar ratio of 2.5:1 at -5℃. The mixture was ultrasonically treated for 35 min, and phosphate buffer was added to maintain the pH at 7.5-8. Then, the mixture was stirred at 200 rpm for 9 h to generate a prepolymer.

[0171] S13. Dry-jet wet spinning: The spinning solution is extruded and placed into a coagulation bath at 15-25℃ with a water and N-methylpyrrolidone mass ratio of 7:3. After preheating and stretching at 250℃ with a stretching ratio of 2:1, the fiber bundle is heat-treated at 350℃ for 35 minutes to obtain modified aramid fiber.

[0172] S2. Pretreatment of modified aramid fibers: The modified aramid fibers are treated with 100W plasma for 5 minutes in an argon atmosphere.

[0173] S3. Spraying the barrier layer: Dissolve fluororubber and polyvinylidene chloride in acetone solution, add nano montmorillonite, and ultrasonically disperse for 35 minutes to obtain the barrier layer. Spray it under a pressure of 0.5 MPa, pre-cur it at 165℃ for 6 minutes, and then deeply vulcanize it at 200℃ for 10 minutes to obtain aramid rope conveyor belt B.

[0174] S4. Preparation of modified polyurethane:

[0175] S41. Preparation of prepolymer: 55% polyester polyol and 18% polydimethylsiloxane were vacuum dehydrated at -0.095 MPa and 80°C for 2 hours, then cooled to 60°C, and 12% isophorone diisocyanate and 0.1% dibutyltin dilaurate were added. The mixture was stirred and reacted under nitrogen protection for 3 hours to obtain the prepolymer.

[0176] S42. Prepolymer modification: Cool the prepolymer to 40℃, slowly add 3% 1,4-butanediol, stir and react for 2h, add 7% tetrahydrofuran to adjust the solid content, then add 4% nano SiO2 and 2% perfluorooctyltriethoxysilane, ultrasonically disperse for 30min, and continue stirring for 1.5h to obtain modified polyurethane.

[0177] S5. Roller-coated hydrophobic and wear-resistant layer: Nano ZnO and titanate coupling agent are premixed and ball-milled for 2.5 hours. Then, modified polyurethane, zinc stearate, and defoamer YRXP-0901 are added sequentially and stirred at 500 rpm for 35 minutes to obtain a hydrophobic and wear-resistant layer. The coating process is adopted with a roller coating speed of 6 m / min and left to stand at 80℃ for 2.5 hours to obtain aramid rope conveyor belt C.

[0178] S6, Elastic Buffer Layer Composite: High-saturation nitrile rubber, carbon black, and dioctyl terephthalate are mixed at 160℃ for 15 minutes, dicumyl peroxide is added, and mixing is continued for 5 minutes to obtain a sheet, which is then placed on the surface of aramid rope conveyor belt C. The molding temperature is 170℃, the pressure is 12MPa, and the pressure is held for 15 minutes to obtain the comparative aramid rope conveyor belt D4.

[0179] Comparative Example 5: This comparative example provides a comparative aramid rope conveyor belt and its preparation method, which is the same as Example 6, except that phosphorylated nanocellulose whiskers are used instead of sulfonated nanocellulose whiskers.

[0180] Comparative Example 6: This comparative example provides a comparative aramid rope conveyor belt and its preparation method, which is the same as Example 6, except that bis[3-(triethoxysilyl)propyl]amine is used instead of bis[3-(trimethoxysilyl)propyl]amine.

[0181] Comparative Example 7: This comparative example provides a comparative aramid rope conveyor belt and its preparation method, which is the same as Example 6, except that 3-carboxyphenylboronic acid is used instead of 4-carboxyphenylboronic acid.

[0182] Salt spray corrosion tests, damp heat aging tests, dynamic fatigue tests, and tensile tests were conducted on the aramid rope conveyor belts #1-#6 obtained in Examples 1-6 and the comparative aramid rope conveyor belts D1-D7 obtained in Comparative Examples 1-7. The test data are shown in Table 1. The salt spray corrosion test was conducted according to ASTM B117 standard for 5000 hours; the damp heat aging test was conducted according to ASTM D3045 standard at 85℃ / 85%RH, measuring the tensile strength retention rate after 1000 hours; the dynamic fatigue test was conducted according to ISO 7623 standard for 10 hours. 6 Modulus decay rate after each cycle; tensile testing was performed according to ASTM D885 standard.

[0183] The data from Examples 1-3, especially Example 3, show that by using a reasonable ratio of the constituent materials of the aramid rope conveyor belt, the aramid rope conveyor belt of this application exhibits excellent performance in all aspects.

[0184] Table 1

[0185]

[0186] Compared to Example 3, Example 4 used the modified polyurethane of this application, and the resulting aramid rope conveyor belt #4 showed superior performance in all aspects compared to the aramid rope conveyor belt #3. This is because the modified polyurethane has a better effect on Cl... - Its osmosis acts as a barrier and can also block Cl. - The diffusion of water molecules prevents droplet retention and hydrolysis. The Si-O-Si backbone and methyl side chains of polydimethylsiloxane impart extremely low surface energy to the coating, inhibiting salt spray droplet spreading. A three-dimensional cross-linked structure is formed through isocyanate curing, blocking Cl... - The diffusion of water molecules is also facilitated. By adding SiO2 and perfluorooctyltriethoxysilane, the perfluorooctyltriethoxysilane is grafted onto the SiO2 surface through hydrolysis and condensation to form Si-O-Si bonds. The SiO2 modified with perfluorooctyltriethoxysilane has a low surface energy and, simultaneously, bonds with the polyurethane prepolymer through hydrogen bonds, achieving a hydrophobic effect. This makes it difficult for salt spray droplets to spread, reducing the risk of corrosion caused by salt crystallization. At the same time, nano-SiO2 acts as a hard filler, improving the hardness and wear resistance of the hydrophobic wear-resistant layer.

[0187] Compared with Example 3, Example 5, and Example 6, compared with Example 4, used the modified aramid fiber of this application. The resulting aramid rope conveyor belt #5 showed superior performance in all aspects compared to aramid rope conveyor belt #3, and the resulting aramid rope conveyor belt #6 showed superior performance in all aspects compared to aramid rope conveyor belt #4. This is because the trimethoxysilane in the bis(trimethoxysilylpropyl)amine of the modified aramid fiber hydrolyzes to generate Si-OH, which condenses to form a siloxane (Si-O-Si) network. The Si-CH3 groups migrate to the fiber surface, covering the fiber surface, reducing surface energy, and inhibiting water molecule penetration. The borate bond (BO) in the 4-carboxyphenylboronic acid ester can reversibly break and recombine under humidity >60%, repairing microcracks. The carboxylic acid group (-COOH) adsorbs Cl through electrostatic interaction. - This reduces its diffusion rate. High aspect ratio sulfonated cellulose nanocrystals are embedded in the aramid matrix to form a nano-bridging network, increasing the tensile modulus. Surface sulfonic acid groups (-SO3H) adsorb Cl... - This forms an ion barrier.

[0188] Compared to Example 6, Comparative Example 1 lacks a composite coating; Comparative Example 2 lacks a hydrophobic wear-resistant layer; Comparative Example 3 lacks a barrier layer; and Comparative Example 4 lacks a filler layer. The resulting comparative aramid rope conveyor belts, compared to aramid rope conveyor belt #6, exhibit decreased performance in all aspects. This is because in the hydrophobic wear-resistant layer, the modified polyurethane reduces surface energy, inhibits salt spray droplet spreading, and lowers the corrosion risk caused by salt crystallization, thus protecting Cl... - The osmosis of Cl also acts as a barrier, blocking its penetration. - This facilitates the diffusion of water molecules, preventing droplet retention and hydrolysis. Nano-ZnO, as a hard filler, enhances the coating's wear resistance. The alkoxy group at one end of the titanate coupling agent reacts with the hydroxyl groups on the ZnO surface. Surface treatment with the titanate coupling agent improves the dispersibility of ZnO in the modified polyurethane. The other end binds to the polar groups of the modified polyurethane, increasing the filler-matrix interface strength and preventing agglomeration. Zinc stearate long-chain alkyl (C...) 18 H 35 This can reduce the surface energy of the coating. Defoamer YRXP-0901 can reduce the surface tension of the coating slurry, breaking up bubbles generated during stirring and coating. In the barrier layer, the high bond energy of the CF bonds in fluororubber can form a dense barrier, reducing Cl... - Permeability coefficient. Polyvinylidene chloride (PVDC) has high crystallinity and tightly packed molecular chains. When blended with fluororubber, it forms a "labyrinth effect," extending the permeability coefficient. - Diffusion pathway, increase Cl - This reduces the difficulty of penetration, achieving the goal of preventing seepage. Nano-montmorillonite can synergistically work with fluororubber to further reduce Cl- content. -The permeability is high. The polytetrafluoroethylene nanoparticles in the filler layer primarily fill the micropores on the surface of the aramid fibers, reducing the specific surface area and blocking capillary permeation of water molecules. Nano-graphene combines with the aramid fibers through π-π stacking to form a conductive network, preventing salt spray adsorption caused by electrostatic accumulation.

[0189] Compared to Example 6, Comparative Example 5 used phosphorylated cellulose nanofibers instead of sulfonated cellulose nanofibers, resulting in a decrease in all properties of the comparative aramid rope conveyor belt. This is because the high aspect ratio sulfonated cellulose nanofibers are embedded in the aramid matrix, forming a nano-bridging network and increasing the tensile modulus. Surface sulfonic acid groups (-SO3H) adsorb Cl... - This forms an ion barrier. The -PO4 group of phosphorylated cellulose nanofibers... 3- -COOH on Cl - Its affinity is much lower than that of sulfonic acid groups (-SO3H), and it has poor salt tolerance.

[0190] Compared to Example 6, Comparative Example 6, which used bis[3-(trimethoxysilyl)propyl]amine instead of bis[3-(trimethoxysilyl)propyl]amine, showed a decrease in all properties of the comparative aramid rope conveyor belt. This is because the trimethoxysilane in bis[3-(trimethoxysilyl)propyl]amine hydrolyzes to generate Si-OH, which condenses to form a siloxane (Si-O-Si) network. The Si-CH3 groups migrate to the fiber surface, covering the fiber surface, reducing surface energy, and inhibiting water molecule penetration. In contrast, the ethoxy group in bis[3-(triethoxysilyl)propyl]amine hydrolyzes more slowly, leading to a decrease in interfacial coupling efficiency. While the ethoxy group has better solubility in non-polar solvents, it is difficult to dissolve in the polar solvent system of this application.

[0191] Compared to Example 6, Comparative Example 7 used 3-carboxyphenylboronic acid instead of 4-carboxyphenylboronic acid, resulting in a decrease in all properties of the comparative aramid rope conveyor belt. This is because the borate bond (BO) in the 4-carboxyphenylboronic acid ester can reversibly break and recombine at humidity >60%, repairing microcracks. The carboxylic acid group (-COOH) adsorbs Cl through electrostatic interaction. - This reduces its diffusion rate. However, due to the different positions of the carboxylic acid groups, steric hindrance in 3-carboxyphenylboronic acid leads to unstable bonding with the aramid backbone. - The adsorption efficiency is reduced. Therefore, the substituted materials in the modified aramid fiber cannot function effectively in the aramid rope conveyor belt; instead, they reduce the belt's performance. Thus, each component cannot be arbitrarily replaced by other materials.

[0192] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An aramid rope conveyor belt, characterized in that, The aramid rope conveyor belt comprises, from the outside to the inside: a composite coating, an aramid rope core layer, and an elastic buffer layer, wherein the thickness ratio of the composite coating, the aramid rope core layer, and the elastic buffer layer is 3-5:8-14:

1. The aramid rope core layer comprises modified aramid fibers. The elastic buffer layer comprises 95-105 parts of high-saturation nitrile rubber, 25-35 parts of carbon black, 2-4 parts of peroxide, and 1-3 parts of plasticizer. The composite coating comprises, from the outside in, a hydrophobic wear-resistant layer, a barrier layer, and a filler layer, with the thickness ratio of the hydrophobic wear-resistant layer, the barrier layer, and the filler layer being 1:1 to 2:

1. The hydrophobic and wear-resistant layer comprises 85-90% modified polyurethane, 3-5% nano ZnO, 3-5% zinc stearate, 2-3% titanate coupling agent, and 1-2% defoamer; the barrier layer comprises 65-70% fluororubber, 25-30% polyvinylidene chloride, and 2-4% nano montmorillonite; and the filler layer comprises 93-97% polytetrafluoroethylene nano-dispersion, 2-4% nano graphene, and 1-3% silane coupling agent. The modified polyurethane is prepared in the following steps: Prepolymer preparation: 50-60% polyester polyol and 15-20% polydimethylsiloxane were vacuum dehydrated at -0.095 MPa and 75-85℃ for 2-3 hours, then cooled to 55-65℃, and 10-15% isophorone diisocyanate and 0.05-0.1% dibutyltin dilaurate were added. The mixture was stirred and reacted under nitrogen protection for 3-4 hours to obtain the prepolymer. Prepolymer modification: Cool the prepolymer to 35-45℃, slowly add 3-4% 1,4-butanediol, stir and react for 2-3 hours, add 3-10% tetrahydrofuran to adjust the solid content, then add 3-5% nano-SiO2 and 1-3% perfluorooctyltriethoxysilane, ultrasonically disperse for 30-40 minutes, and continue stirring for 1-2 hours to obtain modified polyurethane.

2. The aramid rope conveyor belt according to claim 1, characterized in that, The preparation steps of the modified aramid fiber are as follows: Raw material pretreatment: Terephthaloyl chloride, p-phenylenediamine, and bis(trimethoxysilylpropyl)amine were dehydrated under vacuum at -0.095 MPa and 115-125℃ for 4-5 hours; Low-temperature solution polycondensation: 35-40% terephthaloyl chloride, 35-40% p-phenylenediamine, 7-9% bis(trimethoxysilylpropyl)amine, 4-6% 4-carboxyphenylboronic acid ester, and 2-4% sulfonated cellulose nanocrystals are dissolved in a mixed solvent of N-methylpyrrolidone and CaCl2 solution at a molar ratio of 2-3:1 at -3 to -5℃. The mixture is ultrasonically treated for 30-40 min, and phosphate buffer is added to maintain the pH at 7.5-8. Then, the mixture is stirred at 190-210 rpm for 8-10 h to generate a prepolymer. Dry-jet wet spinning: The spinning solution is extruded and placed into a coagulation bath at 15-25℃ with a mass ratio of water to N-methylpyrrolidone of 6-7:3-4. After preheating and stretching at 240-260℃ with a stretching ratio of 2-3:1, the fiber bundle is heat-treated at 340-360℃ for 30-40 minutes to obtain modified aramid fiber.

3. A method for preparing an aramid rope conveyor belt as described in claim 1 or 2, characterized in that, The preparation method includes the following steps: Pretreatment of modified aramid fibers: The modified aramid fibers are treated with plasma at 100-105W for 3-5 minutes in an argon atmosphere; Vacuum pressurized filling layer: Nano-graphene is added to polytetrafluoroethylene nano-dispersion, and pretreated modified aramid fibers are vacuumed at -0.095MPa for 10-12min, pressurized at 1.0-1.2MPa for 15-18min, cyclicated 3-4 times, and then cured at 175-185℃ for 10-12min to obtain aramid rope conveyor belt A; Spraying barrier layer: Fluororubber and polyvinylidene chloride are dissolved in acetone solution, nano-montmorillonite is added, and ultrasonic dispersion is carried out for 30-40 minutes to obtain the barrier layer. The barrier layer is sprayed under a pressure of 0.5-0.6MPa, pre-cured at 160-170℃ for 5-8 minutes, and then deeply vulcanized at 195-205℃ for 10-12 minutes to obtain aramid rope conveyor belt B. Roller-coated hydrophobic and wear-resistant layer: Nano ZnO and titanate coupling agent are premixed and ball-milled for 2-3 hours. Then, modified polyurethane, zinc stearate and defoamer are added in sequence and stirred at 450-550 rpm for 30-40 minutes to obtain a hydrophobic and wear-resistant layer. Roller coating process is used with a coating speed of 5-8 m / min. After standing at 75-85℃ for 2-3 hours, aramid rope conveyor belt C is obtained. Elastic buffer layer composite: High-saturation nitrile rubber, carbon black, and plasticizer are mixed at 155-165℃ for 15-20 minutes, vulcanizing agent is added, and mixing is continued for 5-8 minutes to obtain sheet, thus obtaining an elastic buffer layer. The elastic buffer layer is placed on the C surface of the aramid rope conveyor belt, and the molding temperature is 165-175℃, the pressure is 10-12MPa, and the pressure is held for 15-20 minutes to obtain the aramid rope conveyor belt.

4. An aramid rope conveyor belt for use in ports and in high-humidity, high-salt-spray environments, characterized in that... The aramid rope conveyor belt is prepared using the aramid rope conveyor belt as described in claim 1 or 2, or the aramid rope conveyor belt preparation method as described in claim 3.

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