Heat-resistant conveyor belt and method for producing the same

Abstract

The application discloses a kind of heat-resistant conveying belt and preparation method thereof.A kind of heat-resistant conveying belt, including framework layer and cover glue layer, including the following components: ethylene-propylene-diene rubber 57-63 parts, ethylene-propylene rubber 38-42 parts, carbon black N220 18-22 parts, carbon black N330 33-38 parts, paraffin oil 4-6 parts, zinc oxide 4-7 parts, stearic acid 0.3-0.7 parts, carbon five tackifying resin 10-14 parts, antioxidant RD 1-3 parts, antioxidant MB 1.0-1.8 parts, curing agent DCP 3-5 parts, vulcanization aid TAIC 0.5-1.5 parts, curing agent PDM 0.2-0.8 parts, accelerator TT 0.1-0.5 parts.The application of a variety of components synergistic cooperation, ethylene-propylene-diene rubber, ethylene-propylene rubber cooperation improves heat resistance, carbon five resin provides initial adhesion, subsequent improves the mechanical properties of cover glue.

Description

Technical Field

[0001] This application relates to the technical field of conveyor belts, and in particular to a heat-resistant conveyor belt and a method for preparing the same. Background Technology

[0002] Conveyor belts, as core components for continuous material transport, are widely used in metallurgy, coking, building materials, and chemical industries to transport high-temperature materials such as sintered ore, coke, cement clinker, and hot castings. Intelligent heat treatment production lines typically consist of a feeding unit, a multi-stage heating furnace, a heat preservation section, a quenching / cooling section, a tempering section, an intelligent temperature control system, an atmosphere control system, a conveying system, an online detection and data acquisition system, and a PLC / industrial internet platform. Heat-resistant conveyor belts, as the core conveying carrier in continuous heat treatment lines, are deeply integrated with intelligent systems to achieve a continuous, stable, controllable, and traceable heat treatment process for workpieces. During use, conveyor belts not only withstand the impact of materials at temperatures as high as 150-200℃ or even higher, but also face wear, impact, and thermo-oxidative aging under high-temperature conditions.

[0003] In existing technologies, the main approach to achieving heat resistance in the industry is to use high-performance rubber as the main material for the cover layer. Among them, ethylene propylene rubber (including binary ethylene propylene rubber EPM and ternary ethylene propylene rubber EPDM) has become the preferred matrix material for preparing heat-resistant conveyor belt cover rubber of T4 and above due to its saturated main chain and excellent chemical stability.

[0004] However, existing heat-resistant conveyor belt cover rubbers have the following problems in the preparation process: the high heat-resistant functional fillers added to improve performance have problems such as poor compatibility with the rubber matrix, easy agglomeration and uneven dispersion, resulting in weak interfacial bonding between the fillers and the rubber matrix, making it difficult to form effective chemical bonds and weakening the reinforcement effect.

[0005] Therefore, the development of a heat-resistant conveyor belt with excellent thermal stability, heat insulation and thermal shock resistance, high strength and wear resistance, and strong interlayer adhesion is necessary to enable the conveyor belt to be widely used in intelligent heat treatment production lines. Summary of the Invention

[0006] To address the problem of existing conveyor belts being prone to aging and deformation at high temperatures, resulting in short service life, this application provides a heat-resistant conveyor belt and its preparation method.

[0007] This application provides a heat-resistant conveyor belt, which adopts the following technical solution: A heat-resistant conveyor belt includes a skeleton layer and a cover rubber layer. The raw materials of the cover rubber, by weight, include the following components: 57-63 parts of EPDM rubber, 38-42 parts of EPDM rubber, 18-22 parts of carbon black N220, 33-38 parts of carbon black N330, 4-6 parts of paraffin oil, 4-7 parts of zinc oxide, 0.3-0.7 parts of stearic acid, 10-14 parts of C5 tackifying resin, 1-3 parts of antioxidant RD, 1.0-1.8 parts of antioxidant MB, 3-5 parts of vulcanizing agent DCP, 0.5-1.5 parts of co-vulcanizing agent TAIC, 0.2-0.8 parts of vulcanizing agent PDM, and 0.1-0.5 parts of accelerator TT.

[0008] By adopting the above technical solutions, EPDM rubber provides main chain flexibility and good processability, offering high heat resistance, ozone resistance, aging resistance, high elasticity, and processability. Double bonds provide crosslinking sites, facilitating vulcanization. DIDM rubber has a fully saturated main chain, exhibiting excellent heat and oxygen aging resistance, even higher than EPDM rubber, significantly improving long-term high-temperature aging life and balancing heat resistance, strength, and processability. Carbon black N220, a high-abrasion-resistant carbon black, with small particle size and high structure, imparts excellent tear and abrasion resistance to the rubber compound; carbon black N330, with high elongation, good processability, and easier dispersion, combines reinforcement and abrasion resistance, constructing a high-strength, high-abrasion-resistant, low-heat-generating reinforcing network, suitable for the high-temperature abrasion resistance and impact resistance of heat-resistant conveyor belts.

[0009] Paraffin oil, with its high flash point and low volatility, improves the plasticity of the rubber compound, reduces Mooney viscosity, facilitates mixing and calendering, ensures heat resistance and stability, and prevents softening and loss at high temperatures. Zinc oxide acts as a heat stabilizer and acid absorber in the peroxide system, while stearic acid improves the filler-rubber interface bonding, prevents sticking to rollers, and assists in activating vulcanization. Zinc oxide reacts with stearic acid to form zinc stearate, promoting filler dispersion, activating the vulcanization system, and improving heat resistance and thermal stability. C5 tackifying resin imparts initial tack to the rubber compound, facilitating bonding between the skeleton layer and the capping rubber, does not affect peroxide vulcanization, improves adhesion stability at high temperatures, and prevents delamination.

[0010] Antioxidant RD effectively resists thermo-oxidative aging, inhibits free radical chain reactions, suppresses high-temperature oxidative degradation, and significantly extends thermo-oxidative aging life; Antioxidant MB works synergistically with antioxidant RD to resist thermo-oxidative aging, improves long-term high-temperature aging stability, and has both antioxidant and metal ion passivation effects.

[0011] DCP, the primary vulcanizing agent, decomposes thermally to generate free radicals, causing the carbon chains of ethylene propylene rubber to form CC crosslinks, imparting excellent heat resistance and low compression set. TAIC, the co-vulcanizing agent, works synergistically with DCP to increase crosslink density, shorten vulcanization time, improve crosslink network uniformity and heat resistance, and enhance tear strength. PDM, the vulcanizing agent, improves high-temperature crosslinking efficiency and thermal stability, inhibits premature decomposition of DCP at high temperatures, and improves processing safety and the heat aging resistance of the vulcanized rubber. TT, the accelerator, works synergistically with DCP, TAIC, and PDM to fine-tune the vulcanization rate, prevent scorching, and improve crosslink uniformity, resulting in a more uniform vulcanization degree.

[0012] Multiple components work synergistically. EPDM and EPDM are combined to improve heat resistance. Carbon black N220 and N330 are used for high reinforcement. TAIC and PDM vulcanizing agents increase crosslinking density and improve mechanical properties. C5 resin provides initial tack and peroxide vulcanization to enhance interfacial chemical bonds, improving the adhesion between the cover rubber and the skeleton layer, and subsequently improving the mechanical properties of the cover rubber.

[0013] Preferably, the mass ratio of the EPDM rubber to the EPDM rubber is 1.4-1.6:1.

[0014] By adopting the above technical solutions, EPDM rubber exhibits excellent processing performance, can be sulfur-cured, cross-linked with peroxides, and possesses good elasticity, superior processability, and overall balance, as well as heat resistance. EPDM rubber, with its fully saturated carbon chain and extremely stable molecular chain, exhibits excellent resistance to thermo-oxidative aging and high-temperature heat. The combination of EPDM and EPDM significantly improves the long-term high-temperature service stability of the overall compound, meeting the requirements of high-temperature material conveying and continuous high-temperature operation for heat-resistant conveyor belts. It inhibits thermal aging, hardening, powdering, and cracking; enhances tensile stress and hot dimensional stability at high temperatures; reduces softening deformation and collapse at high temperatures; and balances high-temperature mechanical properties, making the conveyor belt less prone to deformation, bulging, and large permanent deformations. EPDM rubber is responsible for processing, elasticity, vulcanization, and overall mechanical properties, while EPDM rubber is responsible for extreme heat resistance, thermo-oxidative stability, and aging resistance. The blending of the two complements each other, addressing the shortcomings of single EPDM rubber in terms of insufficient heat resistance or poor processability, and is suitable for the long-term high-temperature, dynamic, and aging-resistant use requirements of heat-resistant conveyor belts.

[0015] Preferably, the mass ratio of the vulcanizing agent DCP, the co-vulcanizing agent TAIC, the vulcanizing agent PDM, and the accelerator TT is 10-13:2-7:1-3:1.

[0016] By employing the above technical solutions, the vulcanizing agent DCP decomposes at high temperatures to generate primary free radicals, which abstract hydrogen atoms from the rubber molecular chain to form polymeric free radicals. The co-vulcanizing agent TAIC significantly optimizes the tensile strength and hardness of the vulcanized rubber, improving the product's structural strength and dimensional stability. The vulcanizing agent PDM significantly increases crosslinking density and accelerates vulcanization efficiency. The accelerator TT greatly accelerates the decomposition rate of peroxides such as the vulcanizing agent DCP, ensuring the vulcanization reaction proceeds as planned and is completed more thoroughly, preventing under-vulcanization of the product.

[0017] The vulcanization system, composed of four components, is not a simple additive of raw materials, but a highly integrated network. At the vulcanization temperature, the vulcanizing agent DCP and the accelerator TT decompose or activate upon heating, generating free radicals. The accelerating effect of the accelerator TT ensures the continuous and stable generation of free radicals, preventing the vulcanization process from becoming sluggish. The generated free radicals undergo co-crosslinking reactions with the co-vulcanizing agent TAIC and the vulcanizing agent PDM, forming higher-energy bridge bonds between the rubber molecular chains. This constructs a high-density, high-strength three-dimensional network, meeting the requirements for long-term high-temperature use of the conveyor belt.

[0018] Preferably, the mass ratio of antioxidant RD to antioxidant MB is 1.1-1.5:1.

[0019] By adopting the above technical solutions, antioxidant RD captures free radicals associated with thermo-oxidative aging, inhibiting high-temperature oxidative chain scission and cross-linking aging of rubber. It exhibits strong high-temperature resistance and provides long-term inhibition of hardening, pulverization, and mechanical degradation of rubber compounds at high temperatures. Antioxidant MB assists in capturing peroxide free radicals and decomposing aged peroxides. It has good thermal stability, is not easily volatilized at high temperatures, and is suitable for heat-resistant applications.

[0020] The two components complement each other, doubly blocking the oxidation chain reaction and significantly improving the thermo-oxidative stability of EPDM rubber under long-term high-temperature environments, preventing the conveyor belt cover rubber from softening, cracking, and powdering at high temperatures. The antioxidants RD and MB, when used in combination, produce a synergistic effect, comprehensively inhibiting thermo-oxidative degradation of rubber, ozone cracking, and accelerated aging by metal ions. This significantly improves the stability and service life of the cover rubber layer under high-temperature conditions, and it also exhibits excellent compatibility with peroxide vulcanization systems.

[0021] Preferably, the raw materials also include 10-12 parts of perlite-modified silica and 6-8 parts of ceramic fiber, wherein the perlite-modified silica is composed of perlite, modified nano-silica, and epoxy resin.

[0022] By adopting the above technical solutions, perlite-modified silica has a large specific surface area, excellent reinforcing properties, and improves the density, high temperature resistance, hardness, wear resistance and high temperature insulation of the rubber compound. It fills the gaps between rubber molecules, reduces high temperature air permeability and oxygen permeability, inhibits heat and oxygen aging penetration, improves the heat insulation and heat resistance of the material, and at the same time reduces high temperature thermal shrinkage, reduces thermal deformation, and enhances the overall structural stability.

[0023] Ceramic fibers form a disordered and interwoven fiber network in the rubber matrix, which acts as a micro-skeleton support, significantly improving tensile strength, tear strength, and resistance to flexural fatigue at high temperatures. It is resistant to ultra-high temperatures, non-flammable, and non-melting, and can inhibit the thermal degradation and thermal decomposition of rubber at high temperatures, preventing the cover rubber from cracking, pulverizing, and breaking at high temperatures. The fiber network can disperse stress, reduce the propagation of microcracks caused by dynamic friction and bending, and improve the wear resistance, puncture resistance, and tear resistance of the conveyor belt.

[0024] Perlite-modified silica is composed of perlite, modified nano-silica, and epoxy resin. The modified nano-silica enhances the wear resistance, hardness, and density of the rubber compound, blocks the penetration of oxygen and heat-oxygen media, strengthens aging resistance and high-temperature creep resistance, and is loaded within the pores of perlite to provide dense thermal insulation. Perlite provides thermal insulation and heat resistance, blocks heat conduction inward, reduces the high-temperature thermal aging rate of rubber, and fills the pores of the rubber compound to improve dimensional stability.

[0025] Epoxy resin improves the interfacial bonding between inorganic powders (perlite, silica) and EPDM / dipropylene diene monomer (EPDM) rubber (non-polar rubber), preventing inorganic filler agglomeration and uneven dispersion, enhancing the wettability of inorganic fillers with the rubber matrix, preventing filler detachment and powder spraying, and simultaneously strengthening the overall structural stability. The synergistic effect of these three components improves the conveyor belt's high-temperature resistance and thermal shock resistance, and enhances the rubber compound's high-temperature rigidity, deformation resistance, and resistance to softening and collapse.

[0026] Preferably, the preparation of the modified nano-silica includes the following steps: drying nano-silica at 100-110°C for 1-2 hours, dispersing it in an aqueous solution of silane coupling agent KH570 ethanol, and sonicating it for 15-20 minutes to obtain pretreated nano-silica; then adding carbon dioxide and stirring for 1-1.5 hours, followed by vacuum drying at 60-80°C to obtain modified nano-silica.

[0027] By employing the above technical solution, the nano-silica is dried to remove physically adsorbed water molecules from its surface, exposing the silanol groups on the silica surface and improving the activity of subsequent KH570 grafting reactions. One end of the silane coupling agent KH570 molecule hydrolyzes to generate silanol groups, which then dehydrate and condense with the hydroxyl groups on the nano-silica surface, forming chemical bonds for grafting. The other end contains acrylate organic active groups, transforming the hydrophilic inorganic silica into an oleophilic / organic compatible surface. This solves the problems of silica's tendency to agglomerate and poor compatibility with rubber / resin matrices, resulting in pretreated nano-silica grafted with KH570.

[0028] The introduction of numerous polar active groups such as carboxyl, hydroxyl, and carbonyl groups onto the surface of oxidized carbon fiber eliminates surface inertness, reduces surface smoothness, and increases surface roughness, significantly enhancing the interfacial bonding force between carbon fiber and modified silica and the organic matrix, thus preventing fiber slippage and interfacial delamination. Oxidized carbon fiber is thoroughly mixed and composited with KH570 modified silica, with fibers interpenetrating the powder gaps to construct a particle-fiber composite reinforcement network, synergistically reinforcing, crack-resistant, heat-resistant, and improving dimensional stability and high-temperature mechanical retention.

[0029] The overall process is coherent and coordinated. Drying removes adsorbed water from the surface of nano-silica and activates surface hydroxyl groups. Controllable hydrolysis using KH570 in a weak acid alcohol-water system, combined with ultrasonic dispersion, achieves organic grafting modification of the silica surface. Then, carbon oxide fibers with active groups on the surface are introduced, and the fibers and powder are compounded by mechanical stirring. Finally, the solvent is removed by low-temperature vacuum drying, resulting in modified nano-silica with excellent dispersibility, strong interfacial bonding, and the combined effects of powder densification and reinforcement and fiber toughening and heat resistance.

[0030] Preferably, the ceramic fiber is prepared as follows: the ceramic fiber is dispersed in deionized water, sodium dibutylnaphthalene sulfonate is added, stirred for 30-35 minutes, filtered, and then ground with silicon nitride and mica mixed powder, and dried to obtain ceramic fiber.

[0031] By adopting the above technical solution, sodium dibutylnaphthalene sulfonate reduces the surface tension of ceramic fibers, improves water wettability, eliminates fiber static electricity, prevents agglomeration, and disperses evenly. It adsorbs and adheres to the fiber surface, completes surface activation, increases active adsorption sites, and facilitates the subsequent firm adhesion of silicon nitride and mica powder to the fiber surface.

[0032] Silicon nitride exhibits excellent high-temperature resistance, thermal stability, low coefficient of thermal expansion, and wear and oxidation resistance. During grinding, it adheres to and coats the surface of ceramic fibers, enhancing overall high-temperature dimensional stability, thermal shock resistance, high-temperature oxidation resistance, and wear resistance. Mica mixed powder, in its flaky and layered mineral form, possesses excellent thermal insulation, airtightness, and barrier properties. It adheres to and coats the fiber surface, forming a layered barrier structure that reduces thermal conductivity and strengthens thermal insulation, heat resistance, and resistance to thermal oxygen permeation.

[0033] The components work synergistically, with sodium dibutylnaphthalene sulfonate wetting and activating the fiber surface, followed by grinding and compounding with silicon nitride and mica powder. This allows the high-temperature resistant silicon nitride and layered heat-insulating mica to uniformly coat the fiber surface, followed by drying and shaping. This modification method improves the dispersibility of ceramic fibers in rubber, synergistically enhancing the material's heat resistance, thermal insulation, high-temperature stability, and wear resistance.

[0034] Preferably, the mica mixture powder is composed of mica powder, carboxymethyl cellulose, and sodium lignosulfonate.

[0035] By adopting the above technical solutions, the surface of mica powder has pores and active sites, which enhances its ability to adsorb and bind other components, weakens the interlayer forces of mica sheets, and facilitates subsequent intercalation and coating composites. Carboxymethyl cellulose can form a viscous colloidal solution with adhesion, film-forming, and coating capabilities; the starch system can uniformly coat mica powder and sodium lignosulfonate, forming a continuous organic coating layer after drying.

[0036] Mica powder possesses barrier, heat insulation, temperature resistance, and aging resistance properties, making it a core functional filler. After acid activation, it readily combines with polymeric components. Sodium lignosulfonate reduces interfacial tension, prevents mica sheet aggregation and stacking, improves the interfacial compatibility between inorganic mica and the carboxymethyl cellulose organic phase, promotes uniform coating, and yields a loose, easily dispersed, and firmly coated mica mixture powder.

[0037] Carboxymethyl cellulose (CMC) is modified by sodium lignosulfonate to uniformly coat the surface of activated mica flakes, resulting in a structurally stable and highly dispersible mica powder. This modification enhances the thermal insulation and heat resistance of mica, while also improving its dispersibility and interfacial bonding in rubber systems.

[0038] Secondly, this application also provides a method for preparing a heat-resistant conveyor belt, comprising the following steps: Ethylene propylene diene monomer (EPDM) rubber, ethylene propylene diene monomer (EPDM) rubber, carbon black N220, carbon black N330, paraffin oil, zinc oxide, stearic acid, C5 tackifying resin, antioxidant RD, and antioxidant MB are mixed to obtain masterbatch. The masterbatch, vulcanizing agent DCP, vulcanizing agent TAIC, vulcanizing agent PDM, and accelerator TT are mixed to obtain the final compound, which is then calendered to obtain rubber sheets. The heat-resistant conveyor belt is obtained by laminating the film and the skeleton layer together and then vulcanizing it.

[0039] By adopting the above technical solution and employing a two-stage mixing process, the rubber matrix, reinforcing carbon black, processing aids, tackifying resin, and antioxidants are first mixed to prepare the masterbatch, achieving uniform dispersion of fillers and stable distribution of various functional additives. Then, a composite vulcanization system is added at low temperature to obtain the final compound, effectively preventing scorching of the rubber compound and ensuring processing safety. After being calendered into a uniform sheet, it is laminated with the skeleton layer to form a composite. Finally, high-temperature vulcanization is used to complete cross-linking, curing, and interlayer bonding, resulting in a heat-resistant conveyor belt with stable structure, heat aging resistance, and high strength.

[0040] Preferably, the vulcanization time is 17-22 minutes and the vulcanization pressure is 4-5 kg / cm². 2 The vulcanization temperature is 170-175℃.

[0041] By adopting the above technical solutions, the appropriate temperature ensures the stable decomposition and cross-linking of the peroxide vulcanization system, taking into account both cross-linking efficiency and rubber thermal stability; the reasonable pressure ensures that the cover rubber sheet and the skeleton layer are tightly bonded and compacted, eliminating air bubbles and voids and enhancing interlayer bonding force; and the sufficient vulcanization time ensures that the product is fully vulcanized as a whole, and the cross-linking network is uniform and stable, ultimately giving the heat-resistant conveyor belt excellent heat aging resistance, structural strength and long-term service stability.

[0042] In summary, this application has the following beneficial effects: 1. In this application, multiple components work synergistically. EPDM rubber and EPDM rubber are used to improve heat resistance. Carbon black N220 and carbon black N330 are used for high reinforcement. Vulcanizing agent TAIC and vulcanizing agent PDM increase crosslinking density and improve mechanical properties, thereby improving the mechanical properties of the cover rubber.

[0043] 2. In this application, the accelerator TT works in synergy with the vulcanizing agent DCP, the auxiliary vulcanizing agent TAIC, and the vulcanizing agent PDM to fine-tune the vulcanization rate, prevent scorching, and improve the uniformity of crosslinking, resulting in a more uniform degree of vulcanization.

[0044] 3. In this application, antioxidant MB and antioxidant RD work synergistically to resist heat and oxidation, improve the long-term aging stability at high temperatures, and have both antioxidant and metal ion passivation effects. Detailed Implementation

[0045] The present application will be further described in detail below with reference to the embodiments.

[0046] The raw materials used in the examples and comparative examples are all commercially available.

[0047] Preparation Example 1 The preparation method of perlite-modified silica includes the following steps: 15 kg of perlite was heated at 1100 °C for 3 seconds, cooled, and then dispersed in 30 L of silane coupling agent KH550 ethanol-water solution (ethanol / water mass ratio 90:10). The pH was adjusted to 4 with acetic acid, filtered, and dried to obtain expanded perlite. 1L of waterborne epoxy resin (purchased from Guangzhou Naiboshi Building Materials Co., Ltd.) was dispersed in 50L of deionized water, 5kg of modified nano silica was added, and the mixture was stirred for 25 minutes to obtain a mixture. The mixture was then sprayed onto the surface of expanded perlite, dried, and ground to obtain perlite-modified silica.

[0048] The preparation of modified nano-silica includes the following steps: 5 kg of nano-silica is dried at 100 °C for 1 h, dispersed in 45 L of silane coupling agent KH570 ethanol aqueous solution (KH570:water:ethanol=1:1:4, pH adjusted to 4 with acetic acid), and sonicated for 18 min to obtain pretreated nano-silica; then 1.5 kg of oxidized carbon fiber (oxidized with concentrated nitric acid (mass fraction 68%) at 80 °C for 2 h, with short-cut fiber length 0.5 mm) is added and stirred for 1 h, and vacuum dried at 70 °C to obtain modified nano-silica.

[0049] Preparation Example 2 The difference from Preparation Example 1 is that waterborne epoxy resin is not added in the preparation method of perlite modified silica.

[0050] Preparation Example 3 The difference from Preparation Example 1 is that no modified nano-silica is added in the preparation method of perlite modified silica.

[0051] Preparation Example 4 The difference from Preparation Example 1 is that no silane coupling agent KH570 is added in the preparation of modified nano silica.

[0052] Preparation Example 5 The difference from Preparation Example 1 is that carbon fiber oxide is not added in the preparation of modified nano silica.

[0053] Example 1 A heat-resistant conveyor belt, comprising a skeleton layer and a cover rubber layer, wherein the raw materials of the cover rubber, by weight, comprise the following components: 60 kg of EPDM rubber (EPDM 2470S - Foshan Yihong Chemical Co., Ltd.), 40 kg of EPDM rubber (EPDM KEP110 - Shanghai Huaxiang Polymer Materials Co., Ltd.), 20 kg of carbon black N220, 35 kg of carbon black N330, 5 kg of paraffin oil (model 2280), 5 kg of zinc oxide, 0.5 kg of stearic acid, 12 kg of C5 tackifying resin (AD1200 resin - Shanghai Junyi Chemical Co., Ltd.), 2 kg of antioxidant RD, 1.5 kg of antioxidant MB, 4 kg of vulcanizing agent DCP, 1 kg of vulcanizing aid TAIC, 0.5 kg of vulcanizing agent PDM, and 0.3 kg of accelerator TT.

[0054] The above-mentioned method for preparing a heat-resistant conveyor belt includes the following steps: mixing EPDM rubber, EPDM rubber, carbon black N220, carbon black N330, paraffin oil, zinc oxide, stearic acid, C5 tackifying resin, antioxidant RD, and antioxidant MB at 120°C for 8 minutes to obtain masterbatch. The masterbatch, vulcanizing agent DCP, vulcanizing agent TAIC, vulcanizing agent PDM, and accelerator TT are mixed at 90°C for 3 minutes to obtain the final compound, which is then calendered at 110°C to obtain the rubber sheet. The film and the skeleton layer (nylon canvas, purchased from Shenma Industrial Co., Ltd.) are bonded together to form a heat-resistant conveyor belt with film on both the top and bottom sides of the skeleton layer and vulcanization.

[0055] The thickness of a single layer of film is 6mm.

[0056] The vulcanization time is 20 minutes, and the vulcanization pressure is 5 kg / cm². 2 The vulcanization temperature is 175℃.

[0057] Example 2: A heat-resistant conveyor belt, differing from Example 1 in that the raw materials for the cover rubber, by weight, include the following components: 57 kg of EPDM rubber, 38 kg of EPDM rubber, 22 kg of carbon black N220, 33 kg of carbon black N330, 4 kg of paraffin oil, 7 kg of zinc oxide, 0.7 kg of stearic acid, 10 kg of C5 tackifying resin, 1 kg of antioxidant RD, 1.0 kg of antioxidant MB, 3 kg of vulcanizing agent DCP, 0.5 kg of vulcanizing agent TAIC, 0.2 kg of vulcanizing agent PDM, and 0.1 kg of accelerator TT.

[0058] Example 3: A heat-resistant conveyor belt, differing from Example 1 in that the raw materials for the cover rubber, by weight, include the following components: 63 kg of EPDM rubber, 42 kg of EPDM rubber, 18 kg of carbon black N220, 38 kg of carbon black N330, 6 kg of paraffin oil, 4 kg of zinc oxide, 0.3 kg of stearic acid, 14 kg of C5 tackifying resin, 3 kg of antioxidant RD, 1.8 kg of antioxidant MB, 5 kg of vulcanizing agent DCP, 1.5 kg of vulcanizing agent TAIC, 0.8 kg of vulcanizing agent PDM, and 0.5 kg of accelerator TT.

[0059] Example 4: A heat-resistant conveyor belt, which differs from Example 1 in that the mass ratio of EPDM rubber to EPDM rubber is 2.5:1.

[0060] Example 5: A heat-resistant conveyor belt, which differs from Example 1 in that the mass ratio of vulcanizing agent DCP, co-vulcanizing agent TAIC, vulcanizing agent PDM, and accelerator TT is 3:12:10:1.

[0061] Example 6: A heat-resistant conveyor belt, which differs from Example 1 in that the mass ratio of antioxidant RD to antioxidant MB is 0.5:1.

[0062] Example 7 A heat-resistant conveyor belt, which differs from Example 1 in that the raw materials also include 10 kg of perlite-modified silica and 8 kg of ceramic fiber. The perlite-modified silica is composed of perlite, modified nano silica, and epoxy resin. The perlite-modified silica was prepared in Preparation Example 1. The ceramic fiber was purchased from Lingshou County Chengjiang Mining Processing Plant.

[0063] The above-mentioned method for preparing a heat-resistant conveyor belt includes: mixing EPDM rubber, EPDM rubber, carbon black N220, carbon black N330, perlite-modified silica, ceramic fiber, paraffin oil, zinc oxide, stearic acid, C5 tackifying resin, antioxidant RD, and antioxidant MB at 120°C for 8 minutes to obtain a masterbatch.

[0064] Example 8: A heat-resistant conveyor belt, which differs from Example 7 in that the raw materials also include 12 kg of perlite-modified silica and 6 kg of ceramic fiber.

[0065] Example 9 A heat-resistant conveyor belt, which differs from Example 7 in that the perlite-modified silica is prepared by Preparation Example 2.

[0066] Example 10: A heat-resistant conveyor belt, which differs from Example 7 in that the perlite-modified silica is prepared by Preparation Example 3.

[0067] Example 11 A heat-resistant conveyor belt, which differs from Example 7 in that the perlite-modified silica is prepared by Preparation Example 4.

[0068] Example 12 A heat-resistant conveyor belt, which differs from Example 7 in that the perlite-modified silica is prepared by Preparation Example 5.

[0069] Example 13 A heat-resistant conveyor belt, which differs from Example 7 in that the ceramic fiber is prepared as follows: 10 kg of ceramic fiber is dispersed in 35 L of deionized water, 0.2 kg of sodium dibutylnaphthalene sulfonate is added, stirred for 30 min, filtered, and then ground with 1 kg of silicon nitride and 3 kg of mica powder (ball mill: speed 80 rpm, time 15 min, ball-to-material ratio 2:1), and dried to obtain ceramic fiber.

[0070] The mica mixture powder is composed of mica powder, carboxymethyl cellulose, and sodium lignosulfonate.

[0071] 4 kg of mica powder was dispersed in 20 L of 5% dilute hydrochloric acid solution and soaked for 40 min. After washing with water and drying, pretreated mica powder was obtained. 1.1 kg of carboxymethyl cellulose (Langfang Xingbiao Cellulose Co., Ltd.) was dispersed in 35 L of deionized water and stirred at 90 °C for 15 min. Pretreated mica powder and 0.5 kg of sodium lignosulfonate were added and stirred for 25 min. The mixture was then filtered and freeze-dried (at -40 °C for 24 h) to obtain a mica mixed powder.

[0072] Example 14: A heat-resistant conveyor belt, which differs from Example 12 in that silicon nitride is not added during the preparation of the ceramic fibers.

[0073] Example 15: A heat-resistant conveyor belt, which differs from Example 12 in that mica mixed powder is not added during the preparation of the ceramic fibers.

[0074] Example 16: A heat-resistant conveyor belt, which differs from Example 12 in that carboxymethyl cellulose is not added during the preparation of the mica mixed powder.

[0075] Example 17 A heat-resistant conveyor belt, which differs from Example 12 in that sodium lignosulfonate is not added during the preparation of the mica mixed powder.

[0076] Comparative Example 1 A heat-resistant conveyor belt, which differs from Example 1 in that it does not contain C5 tackifying resin.

[0077] The heat-resistant conveyor belts prepared in Examples 1-17 and Comparative Example 1 were subjected to performance tests. Tensile strength: The tensile strength of the cover rubber was tested according to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0078] Roller friction: The roller friction performance of the conveyor belt is tested according to GB / T7986-2013 "Conveyor Belt Roller Friction Test".

[0079] The conveyor belt was tested for wear using a rubber abrasion tester with a weight load of 2.5 N. The test method was in accordance with GB / T9867-2008.

[0080] Hot air aging test: According to GB / T3513-2001 "Accelerated aging test of vulcanized rubber in hot air", the cover rubber was tested in hot air at 80℃ for 168h. The test results are shown in Table 1.

[0081] Table 1 Test data for the examples and comparative examples

[0082] As can be seen from Table 1, the heat-resistant conveyor belts prepared in Examples 1-3 of this application have good mechanical properties, wear resistance, and aging resistance. Among them, the tensile strength of Example 1 before aging is 29.8 MPa, the change rate of tensile strength after aging is -1.2%, and the wear is 0.0185 cm. 3 ·km -1 It is evident that the heat-resistant conveyor belt prepared in this application possesses excellent mechanical properties. The synergistic combination of multiple components—EPDM rubber and EPDM rubber—enhances heat resistance, while carbon black N220 and N330 provide high reinforcement. The vulcanizing agents TAIC and PDM increase crosslinking density and improve mechanical properties. The C5 resin provides initial tack, and the peroxide vulcanization strengthens interfacial chemical bonds, improving the adhesion between the cover rubber and the skeleton layer.

[0083] Comparative Example 1 did not include C5 tackifying resin. As shown in Table 1, the tensile strength before aging, the rate of change of tensile strength after aging, and the abrasion test results of Comparative Example 1 were significantly worse than those of Examples 1-3. This indicates that the C5 tackifying resin imparts initial tack to the adhesive, facilitating bonding between the skeleton layer and the capping resin, does not affect peroxide vulcanization, improves adhesion stability at high temperatures, and prevents delamination.

[0084] Examples 4-6 varied the mass ratios of EPDM and EPDM, vulcanizing agent DCP, co-vulcanizing agent TAIC, vulcanizing agent PDM, and accelerator TT, as well as the mass ratios of antioxidant RD and antioxidant MB. Table 1 shows that the tensile strength before aging, the rate of change of tensile strength after aging, and the abrasion test results of Examples 4-6 were significantly worse than those of Examples 1-3. This indicates that EPDM is responsible for processing, elasticity, vulcanization, and overall mechanical properties, while EPDM is responsible for extreme heat resistance, thermo-oxidative stability, and aging resistance. The blending of the two solves the problem of insufficient heat resistance of single EPDM, meeting the long-term high-temperature and aging resistance requirements of heat-resistant conveyor belts. The vulcanization system composed of the four components is not a simple superposition of raw materials, but a highly integrated network, constructing a high-density, high-strength three-dimensional network to meet the long-term high-temperature use requirements of conveyor belts. Antioxidant RD and antioxidant MB... When used in combination, it has a synergistic effect. After compounding, it can comprehensively inhibit the thermo-oxidative degradation of rubber, ozone cracking and accelerated aging of metal ions, and significantly improve the stability and service life of the cover layer under high temperature conditions.

[0085] Examples 7-8 also include perlite-modified silica and ceramic fibers in their raw materials. As can be seen from Table 1, the tensile strength before aging, the change rate of tensile strength after aging, and the wear test results of Examples 7-8 are significantly better than those of Examples 1-3. This indicates that perlite-modified silica has excellent reinforcing properties, improving the density, high temperature resistance, hardness, wear resistance, and high temperature insulation of the rubber compound. The ceramic fibers form a disordered and interwoven fiber network in the rubber matrix, playing a micro-skeleton support role and greatly improving the tensile strength, tear strength, and flexural fatigue resistance at high temperatures.

[0086] Examples 9-10 describe the preparation methods of perlite-modified silica without the addition of water-based epoxy resin and modified nano-silica, respectively. As shown in Table 1, the tensile strength before aging, the rate of change of tensile strength after aging, and the wear test results of Examples 9-10 are significantly worse than those of Examples 7-8. This indicates that epoxy resin improves the interfacial bonding force between inorganic powders (perlite, silica) and EPDM / DIDM non-polar rubber, and enhances the wettability of inorganic fillers and rubber matrix; modified nano-silica improves the wear resistance, hardness, and density of the rubber compound, blocks the penetration of oxygen and thermo-oxygen media, and strengthens aging resistance.

[0087] Examples 11-12, which prepared modified nano-silica without the addition of silane coupling agent KH570 and carbon dioxide, show in Table 1 that the tensile strength before aging, the rate of change of tensile strength after aging, and the wear test results of Examples 11-12 are significantly worse than those of Examples 7-8, but better than those of Example 10. This indicates that carbon dioxide reduces surface smoothness and increases surface roughness, significantly improving the interfacial bonding force between carbon dioxide and modified silica and organic matrix, thus preventing fiber slippage and interfacial peeling. The carbon dioxide and KH570 modified silica are fully mixed and composited, with the fibers interpenetrating the gaps between the powder particles to construct a particle-fiber composite reinforcement network, which synergistically strengthens, resists cracking, improves heat resistance, and enhances dimensional stability and high-temperature mechanical retention.

[0088] Example 13: The ceramic fiber prepared using the method described in this application. As shown in Table 1, the tensile strength before aging, the rate of change of tensile strength after aging, and the wear test results of Example 13 are significantly better than those of Examples 7-8. Examples 14-15: In the preparation of the ceramic fiber, neither silicon nitride nor mica mixed powder was added. As shown in Table 1, the tensile strength before aging, the rate of change of tensile strength after aging, and the wear test results of Examples 14-15 are significantly worse than those of Example 13, but better than those of Examples 7-8. This indicates that the modification method described in this application can improve the dispersibility of ceramic fiber in rubber and synergistically enhance the material's heat resistance, thermal insulation, high-temperature stability, and wear protection performance.

[0089] In Examples 16-17, no carboxymethyl cellulose or sodium lignin sulfonate was added during the preparation of the ceramic fibers. Table 1 shows that the tensile strength before aging, the rate of change of tensile strength after aging, and the wear test results of Examples 16-17 were significantly worse than those of Example 13, but better than those of Example 15. This indicates that sodium lignin sulfonate reduces interfacial tension, prevents mica sheet aggregation and stacking, improves the interfacial compatibility between inorganic mica and the organic phase of carboxymethyl cellulose, and promotes uniform coating. The gelatinized starch system can uniformly coat mica powder and sodium lignin sulfonate, forming a continuous organic coating layer after drying.

[0090] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A heat-resistant conveyor belt, comprising a skeleton layer and a cover rubber layer, characterized in that, The raw materials for the capping rubber, by weight, include the following components: 57-63 parts of EPDM rubber, 38-42 parts of EPDM rubber, 18-22 parts of carbon black N220, 33-38 parts of carbon black N330, 4-6 parts of paraffin oil, 4-7 parts of zinc oxide, 0.3-0.7 parts of stearic acid, 10-14 parts of C5 tackifying resin, 1-3 parts of antioxidant RD, 1.0-1.8 parts of antioxidant MB, 3-5 parts of vulcanizing agent DCP, 0.5-1.5 parts of co-vulcanizing agent TAIC, 0.2-0.8 parts of vulcanizing agent PDM, and 0.1-0.5 parts of accelerator TT.

2. The heat-resistant conveyor belt according to claim 1, characterized in that, The mass ratio of the EPDM rubber to the EPDM rubber is 1.4-1.6:

1.

3. The heat-resistant conveyor belt according to claim 1, characterized in that, The mass ratio of the vulcanizing agent DCP, the co-vulcanizing agent TAIC, the vulcanizing agent PDM, and the accelerator TT is 10-13:2-7:1-3:

1.

4. The heat-resistant conveyor belt according to claim 1, characterized in that, The mass ratio of antioxidant RD to antioxidant MB is 1.1-1.5:

1.

5. A heat-resistant conveyor belt according to claim 1, characterized in that, The raw materials also include 10-12 parts of perlite-modified silica and 6-8 parts of ceramic fiber. The perlite-modified silica is composed of perlite, modified nano-silica, and epoxy resin.

6. A heat-resistant conveyor belt according to claim 5, characterized in that, The preparation of the modified nano-silica includes the following steps: drying nano-silica at 100-110℃ for 1-2 hours, dispersing it in an aqueous solution of silane coupling agent KH570 ethanol, and sonicating it for 15-20 minutes to obtain pretreated nano-silica; then adding carbon dioxide and stirring for 1-1.5 hours, followed by vacuum drying at 60-80℃ to obtain modified nano-silica.

7. A heat-resistant conveyor belt according to claim 5, characterized in that, The ceramic fiber is prepared as follows: the ceramic fiber is dispersed in deionized water, sodium dibutylnaphthalene sulfonate is added, stirred for 30-35 minutes, filtered, and then ground with silicon nitride and mica mixed powder, and dried to obtain ceramic fiber.

8. A heat-resistant conveyor belt according to claim 7, characterized in that, The mica mixture powder is composed of mica powder, carboxymethyl cellulose, and sodium lignosulfonate.

9. The method for preparing a heat-resistant conveyor belt according to claim 1, characterized in that, Includes the following steps: Ethylene propylene diene monomer (EPDM) rubber, ethylene propylene diene monomer (EPDM) rubber, carbon black N220, carbon black N330, paraffin oil, zinc oxide, stearic acid, C5 tackifying resin, antioxidant RD, and antioxidant MB are mixed to obtain masterbatch. The masterbatch, vulcanizing agent DCP, vulcanizing agent TAIC, vulcanizing agent PDM, and accelerator TT are mixed to obtain the final compound, which is then calendered to obtain rubber sheets. The heat-resistant conveyor belt is obtained by laminating the film and the skeleton layer together and then vulcanizing it.

10. A heat-resistant conveyor belt according to claim 9, characterized in that, The vulcanization time is 17-22 minutes, and the vulcanization pressure is 4-5 kg / cm². 2 The vulcanization temperature is 170-175℃.

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