Oil-resistant and high-temperature-resistant rubber tube and preparation process thereof

Abstract

The application relates to the field of oil-resistant and high-temperature-resistant rubber pipes, and discloses an oil-resistant and high-temperature-resistant rubber pipe and a preparation process thereof. The core structure of the oil-resistant and high-temperature-resistant rubber pipe comprises three layers: an inner rubber layer, a double-layer reinforcing layer and an outer rubber layer. The inner rubber layer is directly in contact with a transmission medium, and the inner rubber layer is made of fluorine rubber. The oil-resistant and high-temperature-resistant rubber pipe and the preparation process thereof are adopted, the sealing and transmission functions of the rubber pipe are derived from the chemical inertness and compactness of the inner rubber layer. The macromolecular chains of the rubber material are crosslinked by vulcanization to form a three-dimensional network, and the micro-pores of the three-dimensional network are much smaller than fluid molecules, so that physical blocking is realized. The elasticity of the rubber enables the rubber to form an interference fit with a joint, and ensures the static sealing of the joint. The pressure resistance and pulse endurance functions are mainly realized by the reinforcing layer. The introduction of high-strength fibers enables the rubber pipe to withstand the pulse pressure generated by an engine fuel injection system, and the fatigue life of the rubber pipe can reach 200,000 cycles, which is much higher than that of an ordinary plastic pipe.

Description

Technical Field

[0001] This invention relates to the field of oil-resistant and high-temperature resistant rubber hoses, specifically to an oil-resistant and high-temperature resistant rubber hose and its preparation process. Background Technology

[0002] The requirements for components in new energy vehicles (hybrid models) are higher than those in traditional vehicles. Batteries, motors, and motor controllers are all more sensitive to temperature; this is especially true for hybrid models, which include an engine, motor, and battery pack, all within a confined space. Engines operate at high temperatures, generating waste fuel gases. The operating conditions differ from traditional vehicles, necessitating the continuous application of new materials to improve pipeline performance, extend service life, and diversify mounting methods. Simultaneously, there are increasing demands for lightweight design, ease of installation and disassembly, and aesthetics. This requires pipeline suppliers to move beyond simply processing drawings and instead work more closely with OEMs to develop new solutions tailored to the specific characteristics of new energy vehicles.

[0003] New energy vehicles (hybrid models) have an engine, motor, and battery pack coexisting in a confined space within the engine compartment. The engine generates high temperatures and waste oil gases during operation, posing a significant challenge to the performance of the hoses due to prolonged close contact. Therefore, there is an urgent need to update the design of the hose formulation, process, and structure to better meet the requirements of practical applications in terms of density, hardness, strength, and tear resistance. This would significantly improve the structural stability of the hoses under long-term heat exposure, ensuring efficient engine operation over extended periods and increasing the vehicle's driving range. Thus, there is an urgent need for an oil-resistant and high-temperature-resistant hose and its manufacturing process to address these technical challenges. Summary of the Invention

[0004] The purpose of this invention is to provide an oil-resistant and high-temperature resistant rubber hose and its manufacturing process to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An oil-resistant and high-temperature resistant rubber hose, the core structure of which includes three layers: an inner rubber layer, a double-layer reinforcing layer and an outer rubber layer, characterized in that: the inner rubber layer is in direct contact with the transmission medium, and the inner rubber layer is made of fluororubber; The double-layer reinforcing layer is woven and wound with aramid fibers. This double-layer woven and wound structure enhances the stiffness of the tube wall, preventing it from deforming under continuous high pressure, vacuum, or pulsating pressure. The outer adhesive layer is exposed to the engine compartment environment, and high-temperature resistant silicone is preferably used. The high-temperature resistant layer is combined with fabric to control linear expansion.

[0006] A manufacturing process for oil-resistant and high-temperature resistant rubber hoses, the manufacturing process comprising the following steps: Step 1: Material preparation. Before production, confirm that the raw materials meet the process requirements. The materials for the hose assembly include fluororubber, silicone, aramid yarn, high-temperature resistant silicone, etc. Check the batch number, hardness, and tensile strength of the rubber; confirm the diameter and braiding density of the reinforcing layer material; keep the storage environment dry and avoid the materials from getting damp or contaminated. Step 2: Pre-treatment, including impregnation, calendering, and slitting, and the selection of a multi-spindle braiding machine for the aramid fabric with fibers interlaced at a specific angle to enhance stability. Step 3: Inner tube extrusion. Fluororubber raw material is fed into the extruder and heated and plasticized by the screw to form a continuous inner tube. Online monitoring and feedback during the extrusion process: During the extrusion of the inner rubber layer, sensors such as laser diameter gauges and online viscometers are used to monitor the state and size of the rubber material in real time, and the extruder parameters are dynamically adjusted through algorithms to ensure that the uniformity of the tube wall thickness reaches the sub-millimeter level, reducing performance fluctuations from the source. Step 4: Reinforcing layer coating. A reinforcing layer is wrapped around the outside of the inner tube to improve the pressure resistance of the hose. The winding process adopts a spiral laying method, with the ends connected. Step 5: Outer adhesive layer coating. A layer of high-temperature resistant silicone is wrapped around the reinforcing layer for protection. Carbon black and other anti-aging additives are added to the outer adhesive layer, and a specific surface texture is designed to enhance wear resistance. Step 6: Vulcanization treatment. The molded tube blank is introduced into a continuous vulcanization equipment and vulcanized using a microwave-hot air combination method. The rubber tube is fed into the vulcanization equipment for high-temperature fluidization, which crosslinks the rubber molecules. Step 7: Cutting. Cut the long tubing to the specified length according to customer requirements. The cut should be smooth and free of burrs. Step 8: Secondary vulcanization. A vulcanizing tank based on model prediction and control is used. After the rubber hose is cut, the inner sleeve is lined and the outer layer is wrapped with water-soluble cloth. It is then put into the process mold for fluidized forming to obtain the product of the process shape. Step 9: Apply surface printing to the finished product to meet various needs such as functional identification, safety warnings, compliance traceability, and brand management; Step 10: Inspection. Each batch of products must be sampled for pressure testing, burst testing, and pulse testing. The pressure test is 1.5 times the rated pressure, and the pressure must be maintained for 3 minutes without leakage. The burst pressure must reach more than 3 times the rated value. The pulse test simulates actual working conditions and is cyclically pressurized more than 200,000 times. Test data are recorded and archived. Non-conforming products are marked separately and the reasons are analyzed.

[0007] Step 11: Packaging and Storage. After cleaning the surface of the qualified hose assembly, pack it with plastic film or woven bags, add protective sleeves to the joints, and label the packaging box with specifications, production date, batch number and destination area. Keep the warehouse environment well-ventilated and control the temperature between -10℃ and 40℃. Avoid direct sunlight or contact with corrosive substances.

[0008] Preferably, the secondary vulcanization temperature in step eight is 180-200℃, and the time is 2 hours.

[0009] Preferably, in step six, the vulcanization temperature is 170-180℃, the wall thickness is 4.0mm, the vulcanization time is 50 minutes, and the vulcanization pressure is maintained at 0.5MPa.

[0010] Preferably, in step two, the fibers are interwoven at a specific angle, with a weaving angle of 55°.

[0011] Preferably, after the first vulcanization molding, the rubber molecules are not fully cross-linked, and the second vulcanization can further promote the cross-linking reaction and improve tensile strength, resilience, hardness and thermal stability.

[0012] Compared with existing technologies, this invention has the following advantages: The sealing and transmission functions of this hose stem from the chemical inertness and density of the inner rubber layer. The polymer chains of the rubber material form a three-dimensional network through vulcanization cross-linking, and its micropores are much smaller than those of fluid molecules, thus achieving physical barrier. The elasticity of the rubber allows it to form an interference fit with the joint, ensuring a static seal at the connection. The pressure resistance and pulse durability functions are mainly achieved by the reinforcing layer. When the internal fluid pressure increases, the pressure is converted into tensile stress on the reinforcing fibers. The introduction of high-strength fibers enables the hose to withstand pulse pressures of up to several megapascals generated by the engine fuel injection system, and its fatigue life can reach 200,000 cycles, far exceeding that of ordinary plastic hoses.

[0013] Environmental adaptability relies on the synergy of the various material layers. The ozone resistance of the outer layer prevents surface cracking, while the multi-layered structure itself forms a buffer zone against heat and vibration, protecting the stability of the internal fluid state. This functional mechanism contrasts with rigid metal tubes or thermoplastic tubes: metal tubes, while pressure-resistant, cannot dampen vibrations and are complex to mold; single-material thermoplastic tubes often have limited chemical resistance and their resistance to pulse fatigue is usually inferior to that of fiber-reinforced rubber composites.

[0014] Considering the high cost of fluororubber, the pipe adopts an inner fluororubber and outer silicone composite structure, with a fluororubber layer thickness of only 0.6mm, balancing performance and economy.

[0015] It is evident that the pipeline technology researched in this project has reached or exceeded the level of similar technologies both domestically and internationally, meeting the new requirements of new energy vehicles for hoses, while also reducing the cost of automobile production and enhancing the competitiveness of the automotive industry in the international market. Attached Figure Description

[0016] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1Schematic diagram of the overall structure of an oil-resistant and high-temperature-resistant rubber hose of the present invention; Figure 2 Schematic diagram of the 'T-shaped' identification structure of the oil-resistant and high-temperature-resistant rubber hose of the present invention; Figure 3 Schematic diagram of the 'I-shaped' identification structure of the oil-resistant and high-temperature-resistant rubber hose of the present invention; Figure 4 Schematic diagram of the aramid fiber of the present invention. Detailed implementation manners

[0017] The following further elaborates the present application with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant invention and do not limit the invention. Additionally, it should be noted that for the convenience of description, only the parts related to the invention are shown in the drawings. In the drawings of the embodiments of the present invention: Different types of cross-hatchings in the drawings are not marked according to national standards, and there are no requirements for the materials of the components, but are used to distinguish the cross-sectional views of the components in the drawings.

[0018] Please refer to Figure 1-4 , an oil-resistant and high-temperature-resistant rubber hose. The core structure of the oil-resistant and high-temperature-resistant rubber hose includes three layers: an inner rubber layer, a double-layer reinforcement layer, and an outer rubber layer. The inner rubber layer is in direct contact with the transmission medium, and the inner rubber layer is made of fluororubber; The double-layer reinforcement layer is woven and wound by aramid fibers. This double-layer braided wire structure enhances the stiffness of the pipe wall, making it non-deformable under continuous high pressure, vacuum, or pulsating pressure; The outer rubber layer is exposed to the engine compartment environment. Preferably, high-temperature-resistant silica gel is selected, and the high-temperature-resistant layer is combined with the reinforced cloth to control linear expansion.

[0019] A preparation process for an oil-resistant and high-temperature-resistant rubber hose. This preparation process is used to prepare an oil-resistant and high-temperature-resistant rubber hose, and this preparation process includes the following steps: Step 1. Material preparation. Before production, confirm that the raw materials meet the process requirements. The materials for the rubber hose assembly include fluororubber, silica gel, aramid fibers, high-temperature-resistant silica gel, etc. Check the batch number, hardness, and tensile strength of the rubber; confirm the diameter and braiding density of the reinforcement layer materials; keep the storage environment dry to avoid moisture or contamination of the materials; Step 2. Perform pretreatment, including impregnation, calendering, and strip cutting. Select a multi-spindle braiding machine for the braiding process, and the fibers cross and wind at a specific angle to enhance the stability of the aramid cloth; Step 3. Inner tube extrusion. Feed the fluororubber raw material into the extruder, and form a continuous inner tube through screw heating and plasticization; Online monitoring and feedback during the extrusion process: When extruding the inner rubber layer, use sensors such as a laser diameter gauge and an online viscometer to monitor the state and size of the rubber material in real time, and dynamically adjust the parameters of the extruder through an algorithm to ensure that the wall thickness uniformity of the rubber hose reaches sub-millimeter-level accuracy, reducing performance fluctuations from the source; Step 4: Reinforcing layer coating. A reinforcing layer is wrapped around the outside of the inner tube to improve the pressure resistance of the hose. The winding process adopts a spiral laying method, with the ends connected. Step 5: Outer adhesive layer coating. A layer of high-temperature resistant silicone is wrapped around the reinforcing layer for protection. Carbon black and other anti-aging additives are added to the outer adhesive layer, and a specific surface texture is designed to enhance wear resistance. Step 6: Vulcanization treatment. The molded tube blank is introduced into a continuous vulcanization equipment and vulcanized using a microwave-hot air combination method. The rubber tube is fed into the vulcanization equipment for high-temperature fluidization, which crosslinks the rubber molecules. Step 7: Cutting. Cut the long tubing to the specified length according to customer requirements. The cut should be smooth and free of burrs. Step 8: Secondary vulcanization. A vulcanizing tank based on model prediction and control is used. After the rubber hose is cut, the inner sleeve is lined and the outer layer is wrapped with water-soluble cloth. It is then put into the process mold for fluidized forming to obtain the product of the process shape. Step 9: Apply surface printing to the finished product to meet various needs such as functional identification, safety warnings, compliance traceability, and brand management; Step 10: Inspection. Each batch of products must be sampled for pressure testing, burst testing, and pulse testing. The pressure test is 1.5 times the rated pressure, and the pressure must be maintained for 3 minutes without leakage. The burst pressure must reach more than 3 times the rated value. The pulse test simulates actual working conditions and is cyclically pressurized more than 200,000 times. Test data are recorded and archived. Non-conforming products are marked separately and the reasons are analyzed.

[0020] Step 11: Packaging and Storage. After cleaning the surface of the qualified hose assembly, pack it with plastic film or woven bags, add protective sleeves to the joints, and label the packaging box with specifications, production date, batch number and destination area. Keep the warehouse environment well-ventilated and control the temperature between -10℃ and 40℃. Avoid direct sunlight or contact with corrosive substances.

[0021] In step eight, the secondary vulcanization temperature is 180-200℃ and the time is 2 hours.

[0022] In step six, the vulcanization temperature is 170-180℃, the wall thickness is 4.0mm, the vulcanization time is 50 minutes, and the vulcanization pressure is maintained at 0.5MPa.

[0023] In step two, the fibers are intertwined at a specific angle, with a weaving angle of 55°.

[0024] In the case of primary vulcanization, the rubber molecules are not fully cross-linked. Secondary vulcanization can further promote the cross-linking reaction and improve tensile strength, resilience, hardness and thermal stability.

[0025] It should be noted that the process structure and formula of this oil-resistant and high-temperature resistant hose were designed and optimized independently by our company to meet the material and performance requirements of the OEM. Process improvements and automated tooling development were implemented for the assembly process to meet the increasingly complex requirements of pipeline integration design. The technology of this product was entirely developed independently by our company's technical personnel.

[0026] This oil-resistant and high-temperature resistant hose adopts an inner fluorine and outer silicone composite structure, specifically: (from the inside to the outside) special oil-resistant rubber (fluorine rubber) + special rubber (silicone) + reinforcing layer (Kevlar aramid yarn from DuPont, USA) + special rubber (silicone) + reinforcing layer (Kevlar aramid yarn from DuPont, USA) + special high-temperature resistant rubber (high-temperature resistant silicone). The preparation process includes the following steps: Material preparation -- Pretreatment (impregnation, calendering, strip cutting) -- Inner tube extrusion -- Reinforcing layer coating (secondary) -- Outer rubber layer coating -- Vulcanization -- Cutting -- Secondary vulcanization molding -- Printing -- Inspection -- Packaging and warehousing.

[0027] Specifically: I. Material Preparation Before production, it is necessary to confirm that the raw materials meet the process requirements. Materials for hose assemblies include fluororubber, silicone rubber, aramid fiber, and high-temperature resistant silicone rubber. For rubber, the batch number, hardness, and tensile strength must be checked; for reinforcing layer materials, the diameter and braiding density must be confirmed; the storage environment should be kept dry to prevent materials from getting damp or contaminated.

[0028] 1. High-temperature resistant silicone: Withstands temperatures up to 300℃, and short-term temperature up to 350℃. Processed into strips through batching, mixing, and cutting, with a strip thickness of 1.0mm and strip width selected according to final product specifications.

[0029] 2. Silicone: Stable operation within a temperature range of -60℃ to 250℃.

[0030] 3. Fluororubber (FKM): Its long-term operating temperature range is -60℃ to 250℃, and it can withstand short-term temperatures up to 300℃, far exceeding that of traditional rubber materials such as nitrile rubber (NBR). In new energy vehicles, the motor, electronic control system, and battery pack generate significant heat during operation; fluororubber can stably maintain sealing and transport functions. Fluororubber contains fluorine atoms in its molecular chain, forming strong CF bonds that effectively resist the penetration and swelling of hydrocarbon fuels such as gasoline, ethanol blends, and biodiesel. Compared to nitrile rubber, fluororubber has better compatibility with modern unleaded gasoline and high-ethanol fuels, meeting increasingly stringent evaporative emission regulations. Fluororubber is resistant to acids, alkalis, oxidants, and various additives, making it suitable for use in the corrosive coolant (such as glycol-based) or battery electrolyte vapor environments that may occur in new energy vehicles. Fluororubber can significantly reduce the permeability of fuel vapors or volatile organic compounds (VOCs), meeting stringent evaporative emission standards such as China VI. 4. Aramid yarn: Aramid 1313 manufactured by DuPont, USA; it has excellent high-temperature resistance and can be used for a long time at 220℃ without aging. Its electrical and mechanical properties can be maintained for up to 10 years, and it has excellent dimensional stability. The heat shrinkage rate at around 250℃ is only 1%, and it will not shrink, become brittle, soften, or melt even when exposed to 300℃ for a short time. It only begins to decompose at temperatures above 370℃ and begins to carbonize at around 400℃. In addition, it is a flexible polymer material. Its low stiffness and high elongation characteristics give it the same spinnability as ordinary fibers. It can be processed into various fabrics or non-woven fabrics using conventional spinning machines, and it is also wear-resistant and tear-resistant. The tensile strength is 2.0~3.0GPa, and the elongation at break is 15~20%, which is much higher than POD and para-aramid, and its flexibility is better.

[0031] II. Pretreatment (impregnation, calendering, slicing) The selected weaving process uses a multi-spindle weaving machine, and the fibers are interwoven at a specific angle (weaving angle 55°) to enhance the stability of the aramid fabric; The aramid fabric braided structure gives the hose excellent flexibility, facilitating wiring in confined engine compartments and reducing stress from sharp bends. It eliminates metal fatigue issues and avoids the risk of breakage of the steel wire reinforcement layer due to vibration. The reinforcement layer material is not simple fiber, but aramid yarns that have undergone special impregnation treatment. The impregnating agent is a resorcinol-formaldehyde-latex system, whose key role is to establish a strong chemical bond between the reinforcement material and the rubber, ensuring that the layers do not peel off under long-term dynamic stress. Furthermore, the aramid fabric braiding angle is precisely calculated to balance the axial tensile strength and radial expansion rate of the hose.

[0032] After coating the aramid fabric with calendered silicone into sheets (total thickness 0.9mm, including a aramid yarn layer with a thickness of 0.3mm), it is then cut into strips of process width for use.

[0033] III. Inner Tube Extrusion Fluororubber raw material is fed into an extruder and plasticized by screw heating to form a continuous inner tube. Online monitoring and feedback during the extrusion process: During the extrusion of the inner rubber layer, sensors such as a laser diameter gauge and an online viscometer are used to monitor the state and dimensions of the rubber compound in real time. Algorithms dynamically adjust extruder parameters to ensure sub-millimeter precision in the uniformity of the tube wall thickness, reducing performance fluctuations from the source. Tube wall thickness: 0.6mm.

[0034] The extruder temperature is controlled in four stages: feeding zone / 50℃, plasticizing zone / 60℃, homogenizing zone / 65℃, and extrusion zone / 80℃. The feeding zone requires a lower temperature to prevent premature softening and sticking of the rubber; the plasticizing zone needs to be heated to soften and plasticize the rubber; the homogenizing zone requires a stable temperature to ensure uniform rubber distribution; and the extrusion zone requires a suitable temperature to smoothly extrude the rubber into the desired product shape. These temperature zones meet these different needs. Precise temperature zoning improves rubber extrusion efficiency, allowing the rubber to reach the required processing state more quickly, reducing processing time and energy consumption.

[0035] Pressure: 20 MPa; Speed: 5 m / min.

[0036] After extrusion, the inner tube needs to be allowed to cool and stand still to prevent deformation.

[0037] IV. Reinforcing Layer Coverage (Double Layer) A reinforcing layer is wrapped around the outside of the inner tube to improve the hose's pressure resistance. The winding process uses a spiral laying method, with the ends connected.

[0038] The core function of the reinforcing layer is to withstand the pressure generated by the flow of the medium and the pulse pressure of the system. The winding angle of the reinforcing layer is precisely calculated to balance the axial tensile strength and radial expansion rate of the hose, ensuring density consistency.

[0039] Double-layer design, left-hand + right-hand winding method. Winding tension: 1.0MPa, ensuring no air is trapped inside.

[0040] Reinforcing layer thickness: 0.9mm ordinary silicone layer + 0.3mm aramid yarn layer + 0.9mm ordinary silicone layer + 0.3mm aramid yarn layer = 2.4mm; V. Outer adhesive layer coating A layer of high-temperature resistant silicone is wrapped around the reinforcing layer for protection. Since the outer layer is exposed to the engine compartment environment, it needs to withstand ozone, ultraviolet radiation, extreme temperatures, and splashes of various liquids. Simultaneously, the outer layer requires the addition of anti-aging additives such as carbon black and is designed with specific surface textures to enhance wear resistance.

[0041] The winding process also adopts a spiral laying method, with the beginning and end connected. The winding tension is 1.0MPa to ensure that no gas is trapped inside.

[0042] Outer adhesive layer thickness: 1.0mm.

[0043] In steps three, four, and five, the inner rubber compound is extruded to form a continuous tube blank. Immediately afterwards, reinforcing fibers, under precise tension control, are wound and woven at a specific angle onto the tube blank before it has fully cooled and set. Then, the outer rubber layer is immediately laminated and wrapped around the reinforcing layer. The entire process requires a high degree of matching in the preparation speed, temperature, and viscosity of each layer to ensure seamless bonding at the interfaces, eliminating the risk of bubbles or delamination. VI. Vulcanization treatment The molded tube blank is introduced into a continuous vulcanization unit, employing a microwave-hot air combined vulcanization method. Vulcanization is not simply heating; rather, under specific temperature and pressure conditions, it induces a cross-linking reaction in the vulcanizing agent within the rubber compound, transforming linear rubber macromolecules into a three-dimensional network structure. The uniformity of the vulcanization degree (cross-linking density) is crucial, directly determining the hose's pressure resistance, elastic deformation, and heat resistance. Even slight deviations in vulcanization conditions can lead to localized over-vulcanization (embrittlement) or under-vulcanization (insufficient strength). Therefore, precise control of temperature and time matching is essential during the vulcanization process.

[0044] The rubber hose is fed into a vulcanizing device for high-temperature fluidization, causing the rubber molecules to cross-link and improving its elasticity and strength. The vulcanization temperature is 170-180℃, and the wall thickness is 4.0mm; vulcanization time is 50 minutes. The vulcanization pressure is maintained at 0.5MPa to prevent air bubbles from forming inside the hose. After vulcanization, natural cooling is required to avoid stress concentration.

[0045] Intelligent control of vulcanization process: The continuous vulcanization production line can adjust the temperature, pressure and time curves in real time according to the rubber compound formula and product thickness, so that the crosslinking reaction is more complete and uniform, thereby optimizing the final physical properties and service life of the product.

[0046] 7. Cutting: Cut the long tubing to the specified length according to customer requirements. The cut should be flat and free of burrs.

[0047] 8. Secondary vulcanization: A vulcanizing tank based on model prediction and control is used. After slitting, the inner sleeve of the hose is lined with a water-soluble cloth and then placed into a process mold for fluidized bed forming to obtain the product of the process shape.

[0048] Temperature: 180-200℃; Time: 2 hours The effect of secondary vulcanization: Increase crosslinking density: After the first vulcanization (molding), the rubber molecules may not be fully crosslinked. The second vulcanization can further promote the crosslinking reaction and improve tensile strength, resilience, hardness and thermal stability.

[0049] Removal of volatile byproducts: Peroxide sulfidation systems (such as bis(2,4-dichloro) and bis(2,5-dichloro)) will produce low-molecular-weight compounds such as benzene and benzoic acid during the primary sulfidation process. The residues will affect mechanical properties. Secondary sulfidation can volatilize and remove these byproducts.

[0050] Improved odor and safety: Secondary vulcanization can significantly reduce odor and improve product safety and user comfort.

[0051] Stable dimensions and performance: Secondary vulcanization helps reduce shrinkage fluctuations in products, ensuring dimensional stability and long-term performance; secondary vulcanization can uniformly treat two layers of materials, ensuring stable interfacial bonding; 9. Printing, surface printing, to meet various needs such as functional identification, safety warnings, compliance traceability and brand management.

[0052] 10. Inspection: Each batch of products must be sampled for pressure testing, burst testing, and pulse testing. The pressure test is conducted at 1.5 times the rated pressure, maintaining the pressure for 3 minutes without leakage; the burst pressure must reach at least 3 times the rated value; the pulse test simulates actual working conditions, with over 200,000 cyclic pressurization cycles. Test data must be recorded and archived; non-conforming products must be individually marked and the causes analyzed.

[0053] XI. Packaging and Storage: After cleaning the surface of the qualified hose assembly, pack it in plastic film or woven bags, and add protective sleeves to the joints. Label the packaging box with specifications, production date, batch number, and destination area. Maintain a well-ventilated warehouse environment with a temperature controlled between -10℃ and 40℃, and avoid direct sunlight or contact with corrosive substances.

[0054] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0055] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An oil-resistant and high-temperature resistant rubber hose, the core structure of which comprises three layers: an inner rubber layer, a double-layer reinforcing layer, and an outer rubber layer, characterized in that: The inner rubber layer is in direct contact with the transmission medium, and the inner rubber layer is made of fluororubber. The double-layer reinforcing layer is woven and wound with aramid fibers. This double-layer woven structure enhances the stiffness of the tube wall, preventing deformation under continuous high pressure, vacuum, or pulsating pressure. The outer adhesive layer is exposed to the engine compartment environment, and high-temperature resistant silicone is preferably used. The high-temperature resistant layer is combined with fabric to control linear expansion.

2. A process for preparing an oil-resistant and high-temperature resistant rubber hose, characterized in that: The preparation process includes the following steps: Step 1: Material preparation. Before production, confirm that the raw materials meet the process requirements. The materials for the hose assembly include fluororubber, silicone, aramid yarn, high-temperature resistant silicone, etc. Check the batch number, hardness, and tensile strength of the rubber; confirm the diameter and braiding density of the reinforcing layer material; keep the storage environment dry and avoid the materials from getting damp or contaminated. Step 2: Pre-treatment, including impregnation, calendering, and slitting, and the selection of a multi-spindle braiding machine for the aramid fabric where fibers are interlaced at a specific angle to enhance stability. Step 3: Inner tube extrusion. Fluororubber raw material is fed into the extruder and heated and plasticized by the screw to form a continuous inner tube. Online monitoring and feedback during the extrusion process: During the extrusion of the inner rubber layer, sensors such as laser diameter gauges and online viscometers are used to monitor the state and size of the rubber material in real time, and the extruder parameters are dynamically adjusted through algorithms to ensure that the uniformity of the tube wall thickness reaches the sub-millimeter level, reducing performance fluctuations from the source. Step 4: Reinforcing layer coating. A reinforcing layer is wrapped around the outside of the inner tube to improve the pressure resistance of the hose. The winding process adopts a spiral laying method, with the ends connected. Step 5: Outer adhesive layer coating. A layer of high-temperature resistant silicone is wrapped around the reinforcing layer for protection. Carbon black and other anti-aging additives are added to the outer adhesive layer, and a specific surface texture is designed to enhance wear resistance. Step 6: Vulcanization treatment. The molded tube blank is introduced into a continuous vulcanization equipment and vulcanized using a microwave-hot air combination method. The rubber tube is fed into the vulcanization equipment for high-temperature fluidization, which crosslinks the rubber molecules. Step 7: Cutting. Cut the long tubing to the specified length according to customer requirements. The cut should be flat and free of burrs. Step 8: Secondary vulcanization. A vulcanizing tank based on model prediction and control is used. After the rubber hose is cut, the inner sleeve is lined and the outer layer is wrapped with water-soluble cloth. It is then put into the process mold for fluidized molding to obtain the product of the process shape. Step 9: Apply surface printing to the finished product to meet various needs such as functional identification, safety warnings, compliance traceability, and brand management; Step 10: Inspection. Each batch of products must be sampled for pressure testing, burst testing, and pulse testing. The pressure test is 1.5 times the rated pressure, and the pressure must be maintained for 3 minutes without leakage. The burst pressure must reach more than 3 times the rated value. The pulse test simulates actual working conditions and is cyclically pressurized more than 200,000 times. Test data are recorded and archived. Non-conforming products are marked separately and the reasons are analyzed.

3. Step 11: Packaging and Storage. After cleaning the surface of the qualified hose assembly, pack it with plastic film or woven bag, add protective sleeves to the joints, and label the packaging box with specifications, production date, batch number and destination area. Keep the warehouse environment well-ventilated and control the temperature between -10℃ and 40℃. Avoid direct sunlight or contact with corrosive substances.

4. The manufacturing process of an oil-resistant and high-temperature resistant rubber hose according to claim 2, characterized in that: Step 8: Secondary vulcanization temperature: 180-200℃, time: 2 hours.

5. The manufacturing process of an oil-resistant and high-temperature resistant rubber hose according to claim 2, characterized in that: In step six, the vulcanization temperature is 170-180℃, the wall thickness is 4.0mm, the vulcanization time is 50 minutes, and the vulcanization pressure is maintained at 0.5MPa.

6. The manufacturing process of an oil-resistant and high-temperature resistant rubber hose according to claim 2, characterized in that: In step two, the fibers are interwoven at a specific angle, with a weaving angle of 55°.

7. The preparation process of an oil-resistant and high-temperature resistant rubber hose according to claim 2, characterized in that: After the first vulcanization molding, the rubber molecules are not fully cross-linked. Second vulcanization can further promote the cross-linking reaction and improve tensile strength, resilience, hardness and thermal stability.

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