Lightweight aramid fiber woven polytetrafluoroethylene hose and manufacturing method thereof

Abstract

The invention discloses a lightweight aramid fiber woven polytetrafluoroethylene hose and a manufacturing method thereof, and belongs to the technical field of polytetrafluoroethylene tubes. The manufacturing method comprises the following steps: (1) weighing modified PTFE powder and a lubricant, uniformly mixing, standing and curing, and placing in a plunger type PTFE special extruder for extrusion molding to obtain a PTFE tube blank; (2) the PTFE pipe blank is put into a drying oven to be subjected to degreasing treatment; (3) putting the degreased PTFE pipe blank into a sintering furnace, and sintering according to a sintering process curve; and (4) mounting the PTFE base tube obtained by sintering treatment on a braiding machine, and carrying out bidirectional braiding by adopting aramid fibers to prepare the lightweight aramid fiber braided reinforced polytetrafluoroethylene hose. The problems that an existing PTFE hose is large in weight, insufficient in mechanical strength, weak in bonding between a fiber reinforcing layer and a matrix interface, prone to layering and failure and the like are effectively solved, and unification of light weight, high strength and high reliability is achieved.

Description

Technical Field

[0001] This invention belongs to the field of polytetrafluoroethylene (PTFE) tubing technology, specifically relating to a lightweight aramid braided PTFE hose and its manufacturing method. Background Technology

[0002] Polytetrafluoroethylene (PTFE) is widely used in high-end fields such as aerospace, petrochemical, semiconductor manufacturing, and new energy vehicles due to its excellent chemical stability, wide temperature range performance (-200℃~260℃), low coefficient of friction and good electrical insulation. In particular, it is used as the core material for corrosion-resistant fluid transportation hoses.

[0003] However, PTFE itself has inherent defects such as low mechanical strength, poor wear resistance, and susceptibility to cold flow (creep), which limit its direct application under high pressure and high dynamic load conditions. Existing technologies often employ fiber or metal wire braiding reinforcement structures to improve its mechanical properties. Among these, stainless steel wire braided reinforced PTFE hoses are currently a relatively mature technology, but they suffer from problems such as heavy weight, poor flexibility, susceptibility to fatigue fracture, and strong electromagnetic shielding effects, making it difficult to meet the requirements for lightweight and high reliability.

[0004] To improve the performance of the PTFE matrix itself, researchers have attempted to modify it by adding inorganic fillers (such as silica, carbon fiber, and graphene). However, many technical challenges remain, including: poor dispersion of nanofillers; due to the large specific surface area and high surface energy of inorganic particles such as SiO2 and GO (graphene oxide), they are prone to agglomeration in the PTFE matrix, leading to localized stress concentration and reduced overall material performance; weak interfacial bonding; the lack of an effective interfacial compatibility mechanism between the inorganic fillers and the PTFE matrix, making it difficult to form a stable and efficient stress transfer path, thus affecting the reinforcement effect; and deteriorated processing performance; traditional dry mixing processes easily result in uneven filler distribution, and the reduced flowability of modified PTFE powder leads to uneven feeding, material blockage, and strip breakage during extrusion molding, thereby affecting production stability and product consistency. Furthermore, in terms of the structural design of composite hoses, existing fiber reinforcement technologies often employ single-layer or simple braiding methods, which can easily lead to delamination and debonding between the reinforcing fibers and the PTFE base tube under long-term use.

[0005] Therefore, how to develop a new type of PTFE composite hose that combines lightweight, high strength and structural reliability from the perspective of synergistic optimization of material modification and structural design has become one of the technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0006] In view of the shortcomings of the prior art, this invention discloses a lightweight aramid braided polytetrafluoroethylene (PTFE) hose and its manufacturing method. This invention, through the synergistic effect of "material modification, structural design, and process optimization," systematically addresses the issue from three aspects: improving the intrinsic properties of the PTFE matrix, designing a lightweight and high-strength composite structure, and optimizing the multi-layer interface fusion process. This significantly improves the overall performance of the hose. It effectively solves the problems of existing PTFE hoses, such as heavy weight, insufficient mechanical strength, weak bonding between the fiber reinforcement layer and the matrix interface, and susceptibility to delamination failure, achieving a balance between lightweight, high strength, and high reliability.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A lightweight aramid braided polytetrafluoroethylene hose is made from raw materials comprising the following parts by weight: 100 parts modified PTFE powder and 15-20 parts lubricant.

[0009] Preferably, the preparation method of the modified PTFE powder includes the following specific steps:

[0010] S1. Nanocomposite powder: Nano-silica (SiO2) and superlayered graphene oxide (SLGO) are added to ethanol solvent and ultrasonically dispersed for 10-30 min. Then, an appropriate amount of silane coupling agent is added and ultrasonic treatment is continued for 30-60 min to obtain a suspension. The suspension is dried at 60-80℃ to remove the solvent and obtain modified SiO2 / SLGO nanocomposite powder.

[0011] S2. Precursor slurry: Surfynol 104 surfactant is added to a mixed solvent of perfluoropolyether (PFPE) and isopropanol (IPA) and stirred until completely dissolved. Then, PTFE powder and the modified SiO2 / SLGO nanocomposite powder obtained in step S1 are added in sequence and stirred to mix evenly to obtain a stable precursor slurry.

[0012] S3. The slurry obtained in step S2 is spray-dried under the conditions of inlet air temperature of 130-160℃ and outlet air temperature of 60-80℃ to obtain modified PTFE powder.

[0013] Preferably, in step S1, the mass ratio of nano-SiO2 to SLGO is 4:1, and the silane coupling agent is (1-3)% of the total mass of nano-SiO2 and SLGO; the silane coupling agent is KH-550 or KH-570.

[0014] Preferably, in step S2, the mass ratio of the PTFE powder to the modified SiO2 / SLGO nanocomposite powder is 9:1; the mass-volume ratio of the total solids of the PTFE powder and the nanocomposite powder to the PFPE / IPA mixed solvent is 1g:1.2mL.

[0015] Preferably, in step S2, the amount of Surfynol 104 added is 0.5% of the total mass of PTFE powder and nanocomposite powder.

[0016] Preferably, in step S2, the volume ratio of PFPE to IPA in the mixed solvent is 3:1.

[0017] The method for preparing the lightweight aramid braided polytetrafluoroethylene hose described above in this invention includes the following steps:

[0018] (1) Weigh the modified PTFE powder and lubricant according to the weight ratio, put them into the mixer and mix them evenly. After mixing, let them stand and mature for 12-24 hours. Place the matured mixture into a plunger-type PTFE special extruder for extrusion molding to obtain PTFE tube blank.

[0019] (2) Place the PTFE tube blank extruded in step (1) into a hot air circulating oven and degrease it for 4 to 6 hours at 60 to 80°C to remove the lubricant from the tube blank.

[0020] (3) Place the PTFE tube blank after degreasing treatment in step (2) into a sintering furnace, introduce high-purity nitrogen (purity ≥99.99%) as a protective atmosphere, and sinter according to the set sintering process curve to obtain a structurally stable PTFE base tube.

[0021] (4) Install the PTFE base tube obtained in step (3) on a high-speed braiding machine and braid it in both directions using aramid fiber. After each layer of braiding, spray water-based polyurethane emulsion (30% solid content) on the fiber surface and dry it under hot air conditions of 60-80℃ for 10-15 minutes. After all braiding and spraying are completed, place the hose in a low-temperature curing oven and cure it under conditions of 80-100℃ for 30-60 minutes. That is, a lightweight aramid braided reinforced polytetrafluoroethylene hose is obtained.

[0022] Preferably, in step (1), the process parameters of the extruder are set as follows: die temperature 90-110℃, extrusion pressure 15-30MPa, and extrusion speed 10-30mm / min. The lubricant can be paraffin oil, microcrystalline wax, or low molecular weight polyethylene wax.

[0023] Preferably, in step (3), the sintering process is to heat from room temperature to 100°C at a rate of 5-10°C / min and hold for 30 min, then heat to 320°C at a rate of 2-3°C / min and hold for 30 min, then heat to 380°C at a rate of 1-2°C / min and hold for 80-120 min, and then cool naturally to room temperature; the nitrogen protective atmosphere is continuously introduced throughout the sintering process, and the flow rate is controlled at 5-10 L / min.

[0024] Preferably, in step (4), the process parameters of the braiding machine are set as follows: the preset braiding angle is 54±5°, enabling single-layer or multi-layer braiding, the braiding density of each layer is 90% to 100%, the tension of a single fiber bundle is controlled at 5 to 15 N, and the braiding speed is 10 to 30 m / min. The aramid fiber can be... or

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention significantly improves the overall performance of the hose by synergistically combining material modification, structural design, and process optimization. It addresses the intrinsic properties of the PTFE matrix, the lightweight and high-strength design of the composite structure, and the optimization of the multi-layer interface fusion process. Compared to traditional PTFE hose products, this invention achieves significant improvements in mechanical properties and lightweighting, demonstrating outstanding technical advantages and broad application prospects. A detailed analysis follows:

[0027] (1) Material level: Modified PTFE powder achieves intrinsic performance improvement

[0028] This invention employs nano-SiO2 and SLGO to construct a composite filler system. The filler is surface-modified using a silane coupling agent (KH-550 or KH-570) to obtain surface-organized SiO2 / SLGO composite nanoparticles (surface-modified SiO2 / SLGO nanocomposite powder). This nanocomposite powder is uniformly mixed with PTFE powder in a solution system and then spray-dried and granulated to achieve "physical coating + functional modification" of the PTFE powder. Finally, functionalized modified PTFE powder (i.e., modified PTFE powder) is obtained with PTFE as the matrix and surface-modified SiO2 / SLGO nanoparticles loaded on it.

[0029] This method combines the "point-like" rigidity enhancement of SiO2 with the "planar" lamellar barrier effect of SLGO to form a "point-plane" synergistic reinforcement structure. The two-dimensional lamellar structure of SLGO forms a physical barrier in the matrix, restricting the slippage and movement of PTFE molecular chains, thus improving the material's creep resistance and enhancing its barrier properties against gases and liquids. Through the synergistic effect of these two components, the mechanical properties and structural stability of the PTFE matrix are improved. Simultaneously, the introduction of Surfynol 104, a highly efficient surfactant, effectively regulates the dispersion stability of the mixed slurry, significantly improving the dispersion uniformity and interfacial compatibility of the modified SiO2 / SLGO nanocomposite powder in the PTFE matrix, avoiding the agglomeration of nanofillers, and ensuring the stability and batch repeatability of the composite material's performance.

[0030] In addition, by using spray drying technology to co-treat PTFE with nanocomposite fillers, micron-sized spherical particles with concentrated particle size distribution and excellent flowability are obtained. This significantly improves the feeding uniformity of the powder in the subsequent extrusion molding process, effectively reduces process defects such as material blockage and strip breakage, and improves processing stability and molding efficiency.

[0031] (2) Structural level: Aramid weaving reinforcement achieves a lightweight and high-strength composite structure

[0032] ① Lightweight structural design: This invention uses high-strength aramid fiber to replace traditional stainless steel wire as the reinforcing layer, fully utilizing the advantages of aramid fiber such as low density (approximately 1 / 5 that of steel wire), high specific strength, and good flexibility. While ensuring the hose possesses excellent burst pressure resistance and tensile strength, it significantly reduces the overall weight. Actual measurements show that the prepared composite hose is more than 64% lighter than the same specification metal braided PTFE hose, while maintaining a burst pressure of ≥100MPa and exhibiting good bending fatigue life.

[0033] ② In-situ coating of waterborne polyurethane emulsion to enhance interfacial bonding: During the weaving process of aramid fibers, a process of spraying waterborne polyurethane emulsion (30% solid content) layer by layer is adopted. After each layer of weaving is completed, the fiber surface is functionally coated. This process can effectively fill the pores between fibers, improve the sealing performance of the hose, enhance the interfacial adhesion between the reinforcing layer and the PTFE matrix, suppress the delamination and debonding problems that are prone to occur in traditional composite hoses, and improve the structural stability and life of the product.

[0034] (3) Process level: Gradient heating process is adopted.

[0035] ① First stage: Room temperature → 100℃ (rate: 5~10℃ / min, hold for 30min)

[0036] This stage primarily achieves the efficient removal of low-boiling-point components. A temperature of 100℃, slightly higher than the boiling points of water (100℃) and isopropanol (IPA, boiling point 82.5℃), ensures the complete evaporation of residual solvents and moisture. A rapid heating rate (5–10℃ / min) facilitates quickly navigating the evaporation zone, improving thermal efficiency. Holding at this temperature for 30 minutes ensures the volatiles fully escape from the inside of the tube, preventing bubbles, bulges, or micropore defects in the subsequent high-temperature stage; it also prevents structural rupture caused by a sudden increase in vapor pressure, enhancing the density and integrity of the final product.

[0037] ②100℃→320℃ (heating rate: 2~3℃ / min, hold for 30min)

[0038] This temperature range corresponds to the multi-phase transformation zone of PTFE. PTFE undergoes a phase IV to phase III transformation at approximately 115–120℃, with other phase transformations occurring near 190℃ and 327℃. This stage is a "pre-sintering" process, where PTFE particles begin to soften and come into contact with each other, initially bonding and forming a shape. Reducing the heating rate to 2–3℃ / min allows for a smooth passage through multiple phase transformation temperatures, minimizing internal stress caused by uneven thermal expansion. 320℃ is close to the melting point of PTFE (327℃), and holding at this temperature for 30 minutes helps relax the molecular chains and achieve initial fusion, preparing for subsequent complete melting.

[0039] ③ Third stage: 320℃→380℃ (heating rate 1~2℃ / min, holding time 80~120min)

[0040] This stage involves the complete melting and densification of PTFE. A slow heating rate (1–2 °C / min) is used to enter the high-temperature zone, effectively preventing cracking or deformation caused by excessive internal and external temperature differences. 380 °C is approximately 50 °C higher than the melting point of PTFE, which facilitates full melt flow, eliminates internal porosity, and increases material density and mechanical strength. The holding time is set to 80–120 min to ensure uniform heat transfer to thick-walled areas, achieving uniform sintering of the overall structure. Detailed Implementation

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods; unless otherwise specified, the experimental materials used are all commercially available.

[0042] This invention discloses a lightweight aramid braided polytetrafluoroethylene hose, which is made from raw materials comprising the following parts by weight: 100 parts of modified PTFE powder and 15-20 parts of lubricant.

[0043] The specific steps for preparing the modified PTFE powder are as follows:

[0044] S1. Nanocomposite powder: Nano SiO2 and SLGO are added to ethanol solvent at a mass ratio of 4:1 and ultrasonically dispersed for 10-30 min. Then, silane coupling agent (KH-550 or KH-570) equivalent to (1-3)% of the total mass of nano SiO2 and SLGO is added, and ultrasonic treatment is continued for 30-60 min. The resulting suspension is dried at 60-80℃ to remove the solvent, thereby obtaining modified SiO2 / SLGO nanocomposite powder.

[0045] S2. Precursor slurry: Surfynol 104 surfactant was added to a mixed solvent of PFPE and IPA prepared at a volume ratio of 3:1 and stirred until completely dissolved. Then, PTFE powder and the surface-modified SiO2 / SLGO nanocomposite powder obtained in step S1 were added sequentially. The mass ratio of PTFE powder to nanocomposite powder was 9:1, and the mass-volume ratio of the total solids of PTFE powder and nanocomposite powder to the PFPE / IPA mixed solvent was 1g:(1.0~1.5)mL. The amount of Surfynol 104 added was 0.5% of the total mass of PTFE powder and nanocomposite powder. The mixture was stirred continuously to obtain a stable precursor slurry.

[0046] S3. The slurry obtained in step S2 is spray-dried under the conditions of inlet air temperature of 130-160℃ and outlet air temperature of 60-80℃ to obtain modified PTFE powder.

[0047] The aforementioned lubricant can be paraffin oil, microcrystalline wax, or low molecular weight polyethylene wax.

[0048] The present invention also provides a method for manufacturing the above-mentioned lightweight aramid braided polytetrafluoroethylene hose, comprising the following steps:

[0049] (1) Weigh the modified PTFE powder and lubricant according to the weight ratio, put them into the mixer and mix them evenly. After mixing, let them stand and mature for 12-24 hours. Place the matured mixture in a plunger-type PTFE special extruder and extrude it under the following conditions: die temperature 90-110℃, extrusion pressure 15-30MPa, and extrusion speed 10-30mm / min to obtain PTFE tube blank.

[0050] (2) Place the PTFE tube blank extruded in step (1) into a hot air circulating oven and degrease it for 4 to 6 hours at 60 to 80°C to remove the lubricant from the tube blank.

[0051] (3) Place the PTFE tube blank after degreasing treatment in step (2) into a sintering furnace and sinter it under a protective atmosphere of high-purity nitrogen (purity ≥99.99%). The nitrogen flow rate is controlled at 5-10 L / min. The sintering process is as follows: heat up from room temperature to 100℃ at 5-10℃ / min and hold for 30 min, then heat up to 320℃ at 2-3℃ / min and hold for 30 min, then heat up to 380℃ at 1-2℃ / min and hold for 80-120 min, and then cool naturally to room temperature to obtain a structurally stable PTFE base tube.

[0052] (4) Install the PTFE base tube obtained in step (3) on a high-speed braiding machine, using aramid fiber (which can be...). or The process parameters of the braiding machine are set as follows: a preset braiding angle of 54±5°, which can realize single-layer or multi-layer braiding, a braiding density of 90% to 100% per layer, a single fiber tension controlled at 5 to 15N, and a braiding speed of 10 to 30m / min, and bidirectional braiding is carried out; after each layer is braided, water-based polyurethane emulsion (solid content 30%) is sprayed on the fiber surface and dried under hot air at 60 to 80℃ for 10 to 15 minutes; after all braiding and spraying are completed, the hose is placed in a low-temperature curing oven and cured at 80 to 100℃ for 30 to 60 minutes, that is, a lightweight aramid braided reinforced polytetrafluoroethylene hose is obtained.

[0053] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0054] Example 1

[0055] The specific steps for preparing the modified PTFE powder in this embodiment are as follows:

[0056] S1. Nanocomposite powder: 80g of nano SiO2 and 20g of SLGO were added to 400mL of ethanol solvent and ultrasonically dispersed for 20min. Then, 3g of silane coupling agent KH-550 was added and ultrasonic treatment was continued for 45min. The resulting suspension was dried at 70℃ for 12h to completely remove the ethanol solvent and obtain surface-modified SiO2 / SLGO nanocomposite powder.

[0057] S2. Precursor slurry: Add 5.0g of Surfynol 104 surfactant to a mixed solvent consisting of 900mL PFPE and 300mL IPA, and stir until completely dissolved. Then add 900g of PTFE powder and 100g of the above modified SiO2 / SLGO nanocomposite powder in sequence, and continue stirring to obtain a stable precursor slurry.

[0058] S3. The above precursor slurry is spray-dried at an inlet air temperature of 150°C and an outlet air temperature of 70°C to obtain modified PTFE powder.

[0059] The manufacturing method of the lightweight aramid braided polytetrafluoroethylene hose in this embodiment includes the following specific steps:

[0060] (1) Weigh 1000g of modified PTFE powder and 180g of paraffin oil, put them into a mixer and mix them evenly. After mixing, let them stand and mature for 18h. Place the matured mixture in a plunger-type PTFE special extruder and extrude a PTFE tube blank with an inner diameter of 6mm and a wall thickness of 1.2mm under the following process parameters: mold temperature 100℃, extrusion pressure 20MPa, and extrusion speed 20mm / min.

[0061] (2) Place the PTFE tube blank extruded in step (1) into a hot air circulating oven and degrease it for 5 hours at 70°C to remove the lubricant from the tube blank.

[0062] (3) Place the PTFE tube blank after degreasing treatment in step (2) into a sintering furnace and sinter it under a protective atmosphere of high-purity nitrogen (purity ≥99.99%). The nitrogen flow rate is controlled at 8L / min. The sintering process is as follows: heat up from room temperature to 100℃ at 8℃ / min and hold for 30min, then heat up to 320℃ at 2.5℃ / min and hold for 30min, then heat up to 380℃ at 1.5℃ / min and hold for 100min, and then cool naturally to room temperature to obtain a structurally stable PTFE base tube.

[0063] (4) Install the PTFE base tube obtained in step (3) onto a high-speed braiding machine, and use... Aramid fibers are braided in two directions using the following process parameters on a braiding machine: a preset braiding angle of 54±5°, a total of 3 layers, a braiding density of 90% to 100% for each layer, a single fiber tension of 10N, and a braiding speed of 20m / min. After each layer is braided, a water-based polyurethane emulsion (30% solid content) is sprayed onto the fiber surface and dried at 65℃ for 15 minutes, with the spraying thickness controlled at 15μm. After all braiding and spraying are completed, the hose is placed in a low-temperature curing oven and cured at 90℃ for 50 minutes, thus obtaining a lightweight aramid braided reinforced polytetrafluoroethylene hose.

[0064] Example 2

[0065] The specific steps for preparing the modified PTFE powder in this embodiment are as follows:

[0066] S1. Nanocomposite powder: 32g of nano SiO2 and 8g of SLGO were added to 160mL of ethanol solvent and ultrasonically dispersed for 15min. Then, 0.8g of silane coupling agent KH-550 was added and ultrasonic treatment was continued for 30min. The resulting suspension was dried at 75℃ for 10h to completely remove the ethanol solvent and obtain surface-modified SiO2 / SLGO nanocomposite powder.

[0067] S2. Precursor slurry: Add 1.5g of Surfynol 104 surfactant to a mixed solvent consisting of 270mL PFPE and 90mL IPA, and stir until completely dissolved. Then add 270g of PTFE powder and 30g of the above modified SiO2 / SLGO nanocomposite powder in sequence, and continue stirring to obtain a stable precursor slurry.

[0068] S3. The above precursor slurry is spray-dried at an inlet air temperature of 140°C and an outlet air temperature of 65°C to obtain modified PTFE powder.

[0069] The manufacturing method of the lightweight aramid braided polytetrafluoroethylene hose in this embodiment includes the following specific steps:

[0070] (1) Weigh 300g of modified PTFE powder and 45g of microcrystalline wax, put them into a mixer and mix them evenly. After mixing, let them stand and mature for 12 hours. Place the matured mixture in a plunger-type PTFE special extruder and extrude a PTFE tube blank with an inner diameter of 6mm and a wall thickness of 1.2mm under the following process parameters: mold temperature 95℃, extrusion pressure 18MPa, and extrusion speed 10mm / min.

[0071] (2) Place the PTFE tube blank extruded in step (1) into a hot air circulating oven and degrease it at 65°C for 4 hours to remove the lubricant from the tube blank.

[0072] (3) Place the PTFE tube blank after degreasing treatment in step (2) into a sintering furnace and sinter it under a protective atmosphere of high-purity nitrogen (purity ≥99.99%). The nitrogen flow rate is controlled at 5L / min. The sintering process is as follows: heat up from room temperature to 100℃ at 8℃ / min and hold for 30min, then heat up to 320℃ at 2.5℃ / min and hold for 30min, then heat up to 380℃ at 1.5℃ / min and hold for 100min, and then cool naturally to room temperature to obtain a structurally stable PTFE base tube.

[0073] (4) Install the PTFE base tube obtained in step (3) onto a high-speed braiding machine, and use... Aramid fibers are braided in two directions using the following process parameters on a braiding machine: a preset braiding angle of 54±5°, a total of 3 layers, a braiding density of 90% to 100% for each layer, a single fiber tension of 8N, and a braiding speed of 15m / min. After each layer is braided, a water-based polyurethane emulsion (30% solid content) is sprayed onto the fiber surface and dried in hot air at 60℃ for 10 minutes, with the spraying thickness controlled at 10μm. After all braiding and spraying are completed, the hose is placed in a low-temperature curing oven and cured at 80℃ for 60 minutes, thus obtaining a lightweight aramid braided reinforced polytetrafluoroethylene hose.

[0074] Example 3

[0075] The specific steps for preparing the modified PTFE powder in this embodiment are as follows:

[0076] S1. Nanocomposite powder: 200g of nano SiO2 and 50g of SLGO were added to 400mL of ethanol solvent and ultrasonically dispersed for 30min. Then, 7.5g of silane coupling agent KH-550 was added and ultrasonic treatment was continued for 60min. The resulting suspension was dried at 80℃ for 15h to completely remove the ethanol solvent and obtain surface-modified SiO2 / SLGO nanocomposite powder.

[0077] S2. Precursor slurry: Add 10g of Surfynol 104 surfactant to a mixed solvent consisting of 1800mL PFPE and 600mL IPA, and stir until completely dissolved. Then add 1800g of PTFE powder and 200g of the above modified SiO2 / SLGO nanocomposite powder in sequence, and continue stirring to obtain a stable precursor slurry.

[0078] S3. The above precursor slurry is spray-dried at an inlet air temperature of 160°C and an outlet air temperature of 80°C to obtain modified PTFE powder.

[0079] The manufacturing method of the lightweight aramid braided polytetrafluoroethylene hose in this embodiment includes the following specific steps:

[0080] (1) Weigh 2000g of modified PTFE powder and 400g of low molecular weight polyethylene wax, put them into a mixer and mix them evenly. After mixing, let them stand and mature for 24 hours. Place the matured mixture in a plunger-type PTFE special extruder and extrude a PTFE tube blank with an inner diameter of 8mm and a wall thickness of 1.5mm under the following process parameters: mold temperature 110℃, extrusion pressure 30MPa, and extrusion speed 30mm / min.

[0081] (2) Place the PTFE tube blank extruded in step (1) into a hot air circulating oven and degrease it for 6 hours at 80°C to remove the lubricant from the tube blank.

[0082] (3) Place the PTFE tube blank after degreasing treatment in step (2) into a sintering furnace and sinter it under a protective atmosphere of high-purity nitrogen (purity ≥99.99%). The nitrogen flow rate is controlled at 10L / min. The sintering process is as follows: heat up from room temperature to 100℃ at 8℃ / min and hold for 30min, then heat up to 320℃ at 2.5℃ / min and hold for 30min, then heat up to 380℃ at 1.5℃ / min and hold for 100min, and then cool naturally to room temperature to obtain a structurally stable PTFE base tube.

[0083] (4) Install the PTFE base tube obtained in step (3) onto a high-speed braiding machine, and use... Aramid fibers are braided in two directions using the following process parameters on a braiding machine: a preset braiding angle of 54±5°, a total of 3 layers, a braiding density of 90% to 100% for each layer, a single fiber tension of 15N, and a braiding speed of 30m / min. After each layer is braided, a water-based polyurethane emulsion (30% solid content) is sprayed onto the fiber surface and dried at 80℃ for 15 minutes, with the spraying thickness controlled at 20μm. After all braiding and spraying are completed, the hose is placed in a low-temperature curing oven and cured at 100℃ for 30 minutes, thus obtaining a lightweight aramid braided reinforced polytetrafluoroethylene hose.

[0084] Comparative Example 1

[0085] This comparative example uses pure PTFE, and the rest of the process is the same as in Example 1.

[0086] The manufacturing method of the aramid braided polytetrafluoroethylene hose in this comparative example includes the following specific steps:

[0087] (1) Weigh 1000g of PTFE powder and 180g of paraffin oil, put them into a mixer and mix them evenly. After mixing, let them stand and mature for 18 hours. Place the matured mixture in a plunger-type PTFE special extruder and extrude a PTFE tube blank with an inner diameter of 6mm and a wall thickness of 1.2mm under the following process parameters: mold temperature 100℃, extrusion pressure 20MPa, and extrusion speed 20mm / min.

[0088] (2) Place the PTFE tube blank extruded in step (1) into a hot air circulating oven and degrease it for 5 hours at 70°C to remove the lubricant from the tube blank.

[0089] (3) Place the PTFE tube blank after degreasing treatment in step (2) into a sintering furnace and sinter it under a protective atmosphere of high-purity nitrogen (purity ≥99.99%). The nitrogen flow rate is controlled at 8L / min. The sintering process is as follows: heat up from room temperature to 100℃ at 8℃ / min and hold for 30min, then heat up to 320℃ at 2.5℃ / min and hold for 30min, then heat up to 380℃ at 1.5℃ / min and hold for 100min, and then cool naturally to room temperature to obtain a structurally stable PTFE base tube.

[0090] (4) Install the PTFE base tube obtained in step (3) onto a high-speed braiding machine, and use... Aramid fibers are braided in two directions using the following process parameters on a braiding machine: a preset braiding angle of 54±5°, a total of 3 layers, a braiding density of 90% to 100% for each layer, a single fiber tension of 10N, and a braiding speed of 20m / min. After each layer is braided, a water-based polyurethane emulsion (30% solid content) is sprayed onto the fiber surface and dried at 65℃ for 15 minutes, with the spraying thickness controlled at 15μm. After all braiding and spraying are completed, the hose is placed in a low-temperature curing oven and cured at 90℃ for 50 minutes, thus obtaining a lightweight aramid braided reinforced polytetrafluoroethylene hose.

[0091] Comparative Example 2

[0092] This comparative example uses SiO2 / SLGO powder without surface modification; otherwise, the process is the same as in Example 1.

[0093] The manufacturing method of the aramid braided polytetrafluoroethylene hose in this comparative example includes the following specific steps:

[0094] S1. Nanocomposite powder: 80g of nano SiO2 and 20g of SLGO were added to 400mL of ethanol solvent and ultrasonically dispersed for 20min. The resulting suspension was dried at 70℃ for 12h to completely remove the ethanol solvent and obtain SiO2 / SLGO nanocomposite powder.

[0095] S2. Precursor slurry: Add 5.0g of Surfynol 104 surfactant to a mixed solvent consisting of 900mL PFPE and 300mL IPA, and stir until completely dissolved. Then add 900g of PTFE powder and 100g of the above modified SiO2 / SLGO nanocomposite powder in sequence, and continue stirring to obtain a stable precursor slurry.

[0096] S3. The above precursor slurry is spray-dried at an inlet air temperature of 150°C and an outlet air temperature of 70°C to obtain modified PTFE powder.

[0097] The manufacturing method of the aramid braided polytetrafluoroethylene hose in this embodiment includes the following specific steps:

[0098] (1) Weigh 1000g of modified PTFE powder and 180g of paraffin oil, put them into a mixer and mix them evenly. After mixing, let them stand and mature for 18h. Place the matured mixture in a plunger-type PTFE special extruder and extrude a PTFE tube blank with an inner diameter of 6mm and a wall thickness of 1.2mm under the following process parameters: mold temperature 100℃, extrusion pressure 20MPa, and extrusion speed 20mm / min.

[0099] (2) Place the PTFE tube blank extruded in step (1) into a hot air circulating oven and degrease it for 5 hours at 70°C to remove the lubricant from the tube blank.

[0100] (3) Place the PTFE tube blank after degreasing treatment in step (2) into a sintering furnace and sinter it under a protective atmosphere of high-purity nitrogen (purity ≥99.99%). The nitrogen flow rate is controlled at 8L / min. The sintering process is as follows: heat up from room temperature to 100℃ at 8℃ / min and hold for 30min, then heat up to 320℃ at 2.5℃ / min and hold for 30min, then heat up to 380℃ at 1.5℃ / min and hold for 100min, and then cool naturally to room temperature to obtain a structurally stable PTFE base tube.

[0101] (4) Install the PTFE base tube obtained in step (3) onto a high-speed braiding machine, and use... Aramid fibers are braided in two directions using the following process parameters on a braiding machine: a preset braiding angle of 54±5°, a total of 3 layers, a braiding density of 90% to 100% for each layer, a single fiber tension of 10N, and a braiding speed of 20m / min. After each layer is braided, a water-based polyurethane emulsion (30% solid content) is sprayed onto the fiber surface and dried at 65℃ for 15 minutes, with the spraying thickness controlled at 15μm. After all braiding and spraying are completed, the hose is placed in a low-temperature curing oven and cured at 90℃ for 50 minutes, thus obtaining a lightweight aramid braided reinforced polytetrafluoroethylene hose.

[0102] Comparative Example 3

[0103] This comparative example uses a metal braided PTFE hose and 304 stainless steel wire with a diameter of 0.3mm.

[0104] The manufacturing method of the metal braided PTFE hose used in this comparative example includes the following specific steps:

[0105] (1) Weigh 1000g of PTFE powder and dry it at 120℃ for 2 hours to remove moisture. Then, mix it with 180g of paraffin oil in a mixer. After mixing, let it stand for 18 hours to mature. Place the matured mixture in a plunger-type PTFE extruder and extrude it into a tubular structure under the following process parameters: die temperature 105℃, extrusion pressure 25MPa, and extrusion speed 20mm / min to obtain a preliminary PTFE inner lining tube blank.

[0106] (2) The PTFE inner lining tube blank extruded in step (1) is left to stand at room temperature for 1 hour, then placed in an oven and dried at 100°C for 2 hours; then placed in a sintering furnace and sintered under a protective atmosphere of high-purity nitrogen (purity ≥99.99%), with the nitrogen flow rate controlled at 8L / min; the sintering process is as follows: the temperature is increased from room temperature to 100°C at 8°C / min and held for 30 minutes, then increased to 320°C at 2.5°C / min and held for 30 minutes, then increased to 380°C at 1.5°C / min and held for 100 minutes, and then naturally cooled to room temperature to obtain the PTFE base tube.

[0107] (3) Install the PTFE base tube obtained in step (2) on a high-speed braiding machine. Use 304 stainless steel wire with a diameter of 0.3 mm. Set the process parameters of the braiding machine as follows: preset braiding angle 54±5°, a total of 3 layers, each layer's braiding density controlled at 85%~95%, single bundle fiber tension controlled at 10N, and braiding speed 20m / min for bidirectional braiding. After each layer is braided, spray water-based polyurethane emulsion (30% solid content) onto the fiber surface and dry it under 65℃ hot air for 15 min. The spraying thickness is controlled at 15μm. After all braiding and spraying are completed, place the hose in a low-temperature curing oven and cure it at 90℃ for 50 min to obtain the metal braided PTFE hose.

[0108] Performance test results:

[0109] The performance of the polytetrafluoroethylene hoses prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 was tested, as detailed below.

[0110] 1. Sample description for testing:

[0111]

[0112] All the above samples have the same specifications: inner diameter φ6.0mm, wall thickness 1.2mm, and length 1.0m (for testing).

[0113] 2. Performance Testing Methods and Procedures (1) Hose weight reduction (weight per unit length) test to evaluate the lightweighting level of the hose, which directly reflects the optimization effect of materials and structure. The testing steps are as follows:

[0114] ① Take 3 segments of each type of sample, with each segment being exactly 1.0m in length; let them stand for 2 hours under the same conditions;

[0115] ② Use an electronic balance to weigh each section of the hose separately and record the data;

[0116] ③ Calculate the average value as the weight per unit length of the sample (kg / m).

[0117] The measurement data are shown in Table 1 below:

[0118] Table 1

[0119]

[0120]

[0121] As can be seen from Table 1, Example 1 is superior to Comparative Example 1 and Comparative Example 3, achieving a weight reduction of more than 64%; Comparative Example 2 has a slightly higher density due to poor filler dispersion, which verifies the indirect contribution of surface modification to lightweighting.

[0122] (3) Burst pressure test to evaluate the safety limit of the hose under extreme pressure and reflect the joint bearing capacity of the reinforcing layer and the matrix; test standard GB / T 7939-2008 "Test method for hose assembly for hydraulic transmission system".

[0123] Testing equipment: High-pressure hydraulic burst testing machine (pressure range 0~200MPa, accuracy ±0.5%), fixture: φ6mm hose end sealing connector, data acquisition system (real-time recording of pressure-time curves). Testing steps are as follows:

[0124] ① Install sealing connectors at both ends of the 1.0m hose and connect it to the hydraulic system;

[0125] ② Continuously pressurize at a rate of 1.0 MPa / s;

[0126] ③ Monitor pressure changes in real time until the hose ruptures;

[0127] ④ Record the maximum pressure value as the burst pressure; test 3 times for each group and take the average value.

[0128] The measurement data are shown in Table 2 below:

[0129] Table 2

[0130] sample Burst pressure (MPa) Average value (MPa) Example 1 155；152.3；150.8 152.7 Comparative Example 1 155.5；153.3；154.7 154.5 Comparative Example 2 146.2；144.6；144.8 145.2 Comparative Example 3 120.4；132；128.6 127

[0131] As can be seen from Table 2, the burst pressure of Example 1 is significantly better than that of Comparative Example 3, and its weight is 35% of that of Comparative Example 3; Comparative Example 2 has the lowest burst pressure, indicating that poor packing dispersion seriously weakens mechanical properties.

[0132] (4) Bending fatigue life test to evaluate the durability of the hose under dynamic bending conditions, reflecting its flexibility and fatigue resistance.

[0133] Testing equipment: Bending fatigue testing machine (with hydraulic pulse loading function), bending mold: radius R = 30mm, pressure source: 28MPa hydraulic oil, frequency 1Hz.

[0134] The testing steps are as follows:

[0135] ① Install the hose on the testing machine, fix both ends, and pass it around a cylinder with a radius of R=30mm in the middle; apply a 10MPa hydraulic pulse at a frequency of 1Hz; at the same time, perform reciprocating bending (±90° oscillation, frequency 1Hz);

[0136] ② Continue operating until the hose leaks or ruptures;

[0137] ③ Each group was tested 3 times, and the average value was taken.

[0138] The measurement data are shown in Table 3 below:

[0139] Table 3

[0140] sample Number of loops (in ten thousand times) Average (in ten thousand times) Example 1 8.2；8.5；8.0 8.2 Comparative Example 1 4.8；5.0；4.6 4.8 Comparative Example 2 6.0；6.2；5.8 6.0 Comparative Example 3 5.0；4.8；5.2 5.0

[0141] As can be seen from Table 3, Example 1 has the longest bending fatigue life, which is due to the high fatigue resistance of aramid fiber and its flexible structure; although Comparative Example 3 has high strength, the metal wire is prone to fatigue fracture and has poor dynamic performance; Example 1 is superior to Comparative Examples 1-3 in terms of flexibility and durability.

[0142] The overall performance comparison table is shown in Table 4:

[0143] Table 4

[0144]

[0145] As can be seen from Table 4, Example 1, while maintaining a high burst pressure (>100MPa), reduced the unit weight by 22.9% compared to Comparative Example 1 and by about 64% compared to Comparative Example 3, significantly improving the lightweight level of the pipe body; its bending fatigue life reached 82,000 cycles, which is better than Comparative Examples 1, 2 and 3; in addition, the performance of Comparative Example 2 decreased, indicating that the surface modification of SiO2 / SLGO plays a key role in the uniform dispersion and interfacial bonding of the filler.

[0146] In summary, this invention achieves an optimal balance between lightweight, flexibility, durability, and medium- and high-pressure performance through a synergistic design of "nanocomposite modified PTFE + aramid braiding reinforcement," thus solving the problems of "heavy, stiff, and easily fatigued" traditional metal braided hoses.

[0147] The present invention provides a detailed description of a lightweight aramid braided polytetrafluoroethylene hose and its manufacturing method. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these examples are merely illustrative and are intended to help understand the method and core concepts of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.

Claims

1. A lightweight aramid braided polytetrafluoroethylene hose, characterized in that, It is made from raw materials containing the following parts by weight: 100 parts modified PTFE powder and 15-20 parts lubricant.

2. The lightweight aramid braided polytetrafluoroethylene hose according to claim 1, characterized in that, The specific steps for preparing the modified PTFE powder are as follows: S1. Nanocomposite powder: Nano SiO2 and SLGO are added to ethanol solvent and ultrasonically dispersed for 10-30 min. Then, an appropriate amount of silane coupling agent is added and ultrasonic treatment is continued for 30-60 min to obtain a suspension. The suspension is dried at 60-80℃ to remove the solvent and obtain modified SiO2 / SLGO nanocomposite powder. S2. Precursor slurry: Surfynol 104 surfactant is added to a mixed solvent of PFPE and IPA and stirred until completely dissolved. Then, PTFE powder and the modified slurry obtained in step S1 are added sequentially. SiO2 / SLGO nanocomposite powder was stirred and mixed evenly to obtain a stable precursor slurry. S3. The slurry obtained in step S2 is spray-dried under the conditions of inlet air temperature of 130-160℃ and outlet air temperature of 60-80℃ to obtain modified PTFE powder.

3. The lightweight aramid braided polytetrafluoroethylene hose according to claim 2, characterized in that, In step S1, the mass ratio of nano-SiO2 to SLGO is 4:1, and the silane coupling agent is (1-3)% of the total mass of nano-SiO2 and SLGO; the silane coupling agent is KH-550 or KH-570.

4. The lightweight aramid braided polytetrafluoroethylene hose according to claim 2, characterized in that, In step S2, the mass ratio of the PTFE powder to the modified SiO2 / SLGO nanocomposite powder is 9:1; the mass-volume ratio of the total solids of the PTFE powder and nanocomposite powder to the PFPE / IPA mixed solvent is 1g:1.2mL.

5. The lightweight aramid braided polytetrafluoroethylene hose according to claim 4, characterized in that, In step S2, the amount of Surfynol 104 added is 0.5% of the total mass of PTFE powder and nanocomposite powder.

6. The lightweight aramid braided polytetrafluoroethylene hose according to claim 2, characterized in that, In step S2, the volume ratio of PFPE to IPA in the mixed solvent is 3:

1.

7. A method for manufacturing a lightweight aramid braided polytetrafluoroethylene hose as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Weigh the modified PTFE powder and lubricant according to the weight ratio, put them into the mixer and mix them evenly. After mixing, let them stand and mature for 12-24 hours. Place the matured mixture into a plunger-type PTFE special extruder for extrusion molding to obtain PTFE tube blank. (2) Place the PTFE tube blank extruded in step (1) into a hot air circulating oven and degrease it for 4 to 6 hours at 60 to 80°C to remove the lubricant from the tube blank. (3) Place the PTFE tube blank after degreasing treatment in step (2) into a sintering furnace, introduce high-purity nitrogen (purity ≥99.99%) as a protective atmosphere, and sinter according to the set sintering process curve to obtain a structurally stable PTFE base tube. (4) Install the PTFE base tube obtained in step (3) on a high-speed braiding machine and braid it in both directions using aramid fiber. After each layer of braiding, spray water-based polyurethane emulsion (30% solid content) on the fiber surface and dry it under hot air conditions of 60-80℃ for 10-15 minutes. After all braiding and spraying are completed, place the hose in a low-temperature curing oven and cure it under conditions of 80-100℃ for 30-60 minutes. That is, a lightweight aramid braided reinforced polytetrafluoroethylene hose is obtained.

8. The method for preparing the lightweight aramid braided polytetrafluoroethylene hose according to claim 7, characterized in that, In step (1), the process parameters of the extruder are set as follows: die temperature 90~110℃, extrusion pressure 15~30MPa, and extrusion speed 10~30mm / min.

9. The method for preparing the lightweight aramid braided polytetrafluoroethylene hose according to claim 7, characterized in that, In step (3), the sintering process is as follows: the temperature is increased from room temperature to 100℃ at 5-10℃ / min and held for 30min, then increased to 320℃ at 2-3℃ / min and held for 30min, then increased to 380℃ at 1-2℃ / min and held for 80-120min, and then naturally cooled to room temperature; the nitrogen protective atmosphere is continuously introduced throughout the sintering process, and the flow rate is controlled at 5-10L / min.

10. The method for preparing the lightweight aramid braided polytetrafluoroethylene hose according to claim 7, characterized in that, In step (4), the process parameters of the braiding machine are set as follows: the preset braiding angle is 54±5°, which can realize single-layer or multi-layer braiding, the braiding density of each layer is 90% to 100%, the tension of a single bundle of fibers is controlled at 5 to 15N, and the braiding speed is 10 to 30m / min.

Images