Self-lubricating fabric composite material with low starting friction torque and preparation method thereof

Abstract

The invention belongs to the technical field of lubricating materials, and particularly relates to a low-starting friction torque self-lubricating fabric composite material and a preparation method thereof. The preparation method comprises the following steps: by taking a polytetrafluoroethylene dispersion liquid as a spraying solution, depositing polytetrafluoroethylene nano-particles on the surface of a fiber fabric by adopting an electrostatic spraying method, so as to obtain an electrostatic spraying polytetrafluoroethylene compound fabric; the electrostatic spraying polytetrafluoroethylene composite fabric is subjected to plasma etching treatment and then impregnated-dried through a resin solution, and self-lubricating fabric prepreg is obtained; and curing and forming the self-lubricating fabric prepreg to obtain the low-starting friction torque self-lubricating fabric composite material. The starting friction torque of the self-lubricating fabric composite material can be effectively reduced, abrasion aggravation or failure of the lubricating material caused by too large starting friction torque is avoided, and then the use reliability and the service life of the self-lubricating fabric composite material and related moving parts are improved.

Description

Technical Field

[0001] This invention belongs to the field of lubrication material technology, specifically relating to a low-starting-friction torque self-lubricating fabric composite material and its preparation method. Background Technology

[0002] Self-lubricating fabric composites are typically made by weaving polytetrafluoroethylene (PTFE) fibers with reinforcing fibers, impregnating them with resin solutions, and curing them at high temperatures. They possess stable lubrication characteristics without the need for additional lubricating oils or greases, and also exhibit excellent mechanical properties and designability, making them widely used in lubrication systems for high-end equipment in aerospace, rail transportation, and other industries. The wear process of self-lubricating fabric composites generally consists of three stages: the initial break-in wear stage, the stable wear stage, and the severe wear stage. In the initial break-in wear stage, the pressure at the actual contact point between the self-lubricating fabric composite and its mating surface is high. At this time, the surface morphology of the self-lubricating fabric composite changes drastically, and the starting frictional torque rises rapidly. A large starting frictional torque can exacerbate wear and even directly lead to early wear failure.

[0003] Therefore, reducing the starting friction torque of self-lubricating fabric composites during the break-in and wear stages, and improving their break-in performance, is particularly important. However, there are no reports on improving the starting friction torque performance of existing self-lubricating fabric composites. Summary of the Invention

[0004] The purpose of this invention is to provide a low-starting-friction-torque self-lubricating fabric composite material and its preparation method. The low-starting-friction-torque self-lubricating fabric composite material provided by this invention can promote the rapid formation of a lubrication transfer film, thereby reducing the starting-friction torque and extending the reliability and service life of the self-lubricating fabric composite material and related moving parts.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a self-lubricating fabric composite material with low starting friction torque, comprising the following steps: Using polytetrafluoroethylene dispersion as a spray solution, polytetrafluoroethylene nanoparticles are deposited on the surface of fiber fabric by electrostatic spraying to form an electrostatic sprayed polytetrafluoroethylene nanoparticle layer, thus obtaining an electrostatic sprayed polytetrafluoroethylene composite fabric. The electrostatic sprayed polytetrafluoroethylene composite fabric is subjected to plasma etching treatment, and then impregnated and dried with resin solution to obtain a self-lubricating fabric prepreg. The self-lubricating fabric prepreg is cured and molded to obtain the low starting friction torque self-lubricating fabric composite material.

[0006] Preferably, the method for preparing the polytetrafluoroethylene dispersion includes: mixing polytetrafluoroethylene concentrate and deionized water and then subjecting the mixture to ultrasonic treatment to obtain the polytetrafluoroethylene dispersion; the solid content of polytetrafluoroethylene in the polytetrafluoroethylene concentrate is 50-60%, the volume ratio of the polytetrafluoroethylene concentrate to deionized water is 1:0.1-5, and the ultrasonic treatment time is 30-200 min.

[0007] Preferably, the particle size of the polytetrafluoroethylene particles in the polytetrafluoroethylene dispersion is 0.1~0.5μm.

[0008] Preferably, the fiber fabric is a blend of polytetrafluoroethylene fiber and reinforcing fiber, wherein the reinforcing fiber includes one or more of aramid fiber, liquid crystal fiber, polyimide fiber, polyaryl ester fiber and poly(p-phenylenebenzodioxazole) (PBO) fiber.

[0009] Preferably, the conditions for electrostatic spraying include: a voltage of 10~18 kV, a constant propulsion speed of PTFE dispersion of 0.1~1.0 mL / h, a receiving distance of 10~30 cm between the electrostatic spraying needle and the receiving device, a left-right moving speed of the electrostatic spraying needle of 5~50 mm / s, and a rotation speed of the receiving roller of 100~400 r / min.

[0010] Preferably, the mass of the electrostatically sprayed polytetrafluoroethylene nanoparticle layer is 0.1 × 10⁻⁶. -4 ~5×10 -4 g / cm 2 .

[0011] Preferably, the conditions for the plasma etching process include: a power of 20~200W and a time of 1~30min.

[0012] Preferably, after the plasma etching process, the plasma-treated electrostatic sprayed polytetrafluoroethylene composite fabric is obtained, and the mass percentage of the plasma-treated electrostatic sprayed polytetrafluoroethylene composite fabric in the self-lubricating fabric prepreg is 60-90%.

[0013] Preferably, the curing conditions include: curing pressure of 0.1~0.5MPa, curing temperature of 160~200℃, and curing time of 1~2h.

[0014] The present invention provides a low-starting-friction torque self-lubricating fabric composite material prepared by the preparation method described in the above technical solution.

[0015] This invention provides a method for preparing a low-starting-friction torque self-lubricating fabric composite material, comprising the following steps: using a polytetrafluoroethylene (PTFE) dispersion as a spray solution, electrostatic spraying is used to deposit PTFE nanoparticles on the surface of a fiber fabric to form an electrostatically sprayed PTFE nanoparticle layer, resulting in an electrostatically sprayed PTFE composite fabric; the electrostatically sprayed PTFE composite fabric is subjected to plasma etching treatment, followed by impregnation and drying with a resin solution to obtain a self-lubricating fabric prepreg; the self-lubricating fabric prepreg is then cured to obtain the low-starting-friction torque self-lubricating fabric composite material. The preparation method provided by this invention is based on the extremely low coefficient of friction and high specific surface area of ​​PTFE nanoparticles. Electrostatic spraying technology is used to uniformly coat the surface of the fiber fabric with a layer of PTFE nanoparticles, forming a low-friction coefficient coating; plasma etching is used to improve its surface activity, followed by impregnation and drying with a resin solution, and curing to obtain the low-starting-friction torque self-lubricating fabric composite material. The PTFE nanoparticle coating prepared by electrostatic spraying in this invention can accelerate the formation of transfer film on the mating surface. The rolling effect and low friction coefficient of PTFE nanoparticles can improve the tribological properties of the self-lubricating fabric surface, thereby effectively reducing the starting friction torque of the self-lubricating fabric composite material. This avoids the aggravation of wear or failure of the lubricating material due to excessive starting friction torque, and thus extends the reliability and service life of the self-lubricating fabric composite material and related moving parts.

[0016] This invention provides a low-starting-friction-torque self-lubricating fabric composite material prepared by the preparation method described above. The low-starting-friction-torque self-lubricating fabric composite material provided by this invention comprises a plasma-treated electrostatically sprayed polytetrafluoroethylene (PTFE) composite fabric and a resin material composited on the plasma-treated electrostatically sprayed PTFE composite fabric. This invention increases the PTFE content on the fabric surface by electrostatically spraying PTFE nanoparticles, accelerating the formation of a transfer film on the mating surface. The rolling effect and low coefficient of friction of the PTFE nanoparticles improve the tribological properties of the self-lubricating fabric surface, thereby effectively reducing the starting friction torque of the self-lubricating fabric composite material during the break-in and wear stages, resulting in good break-in performance, and to a certain extent reducing the wear amount and coefficient of friction of the self-lubricating fabric composite material. Attached Figure Description

[0017] Figure 1 This is a field emission scanning electron microscope (SEM) image of the electrostatically sprayed PTFE nanoparticles in Example 1. Figure 2 The bar chart shows the maximum starting frictional torque of the fabric composites prepared in Comparative Examples 1-3 and Examples 1-3; Figure 3A comparison of the friction torque curves of the fabric composite materials prepared in Comparative Example 1 and Example 1; Figure 4 A comparison of the friction torque curves of the fabric composite materials prepared in Comparative Example 2 and Example 2; Figure 5 A comparison of the friction torque curves of the fabric composite materials prepared in Comparative Example 3 and Example 3. Detailed Implementation

[0018] This invention provides a method for preparing a self-lubricating fabric composite material with low starting friction torque, comprising the following steps: Using polytetrafluoroethylene dispersion as a spray solution, polytetrafluoroethylene nanoparticles are deposited on the surface of fiber fabric by electrostatic spraying to form an electrostatic sprayed polytetrafluoroethylene nanoparticle layer, thus obtaining an electrostatic sprayed polytetrafluoroethylene composite fabric. The electrostatic sprayed polytetrafluoroethylene composite fabric is subjected to plasma etching treatment, and then impregnated and dried with resin solution to obtain a self-lubricating fabric prepreg. The self-lubricating fabric prepreg is cured and molded to obtain the low starting friction torque self-lubricating fabric composite material.

[0019] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0020] This invention uses a polytetrafluoroethylene dispersion as a spray solution and employs an electrostatic spraying method to deposit polytetrafluoroethylene nanoparticles on the surface of a fiber fabric, forming an electrostatic sprayed polytetrafluoroethylene nanoparticle layer, thereby obtaining an electrostatic sprayed polytetrafluoroethylene composite fabric.

[0021] In this invention, the preferred method for preparing the polytetrafluoroethylene (PTFE) dispersion includes: mixing a concentrated PTFE solution with deionized water and then subjecting it to ultrasonic treatment to obtain the PTFE dispersion. In this invention, the solid content of PTFE in the concentrated PTFE solution is preferably 50-60%, and in the examples, it can be 60%. The volume ratio of the concentrated PTFE solution to deionized water is preferably 1:0.1-5, more preferably 1:0.5-1:2, and in the examples, it can be 1:1, 1:2, or 1:0.5. The ultrasonic treatment time is preferably 30-200 min, more preferably 60-120 min, and in the examples, it can be 120 min. This invention, by diluting the concentrated PTFE solution with deionized water and then subjecting it to ultrasonic treatment, facilitates the uniform dispersion of PTFE nanoparticles in the solution.

[0022] In this invention, the particle size of the polytetrafluoroethylene particles in the polytetrafluoroethylene dispersion is preferably 0.1~0.5μm, more preferably 0.1~0.4µm, and even more preferably 0.1~0.25µm.

[0023] In this invention, the fiber fabric is preferably a blend of polytetrafluoroethylene (PTFE) fibers and reinforcing fibers. The blend of PTFE fibers and reinforcing fibers is preferably woven using one or more of the following structures: plain weave, twill weave, satin weave, and fabric structures derived from the three-phase weave structure. The reinforcing fibers preferably include one or more of aramid fibers, liquid crystal fibers, polyimide fibers, polyaryl ester fibers, and poly(p-phenylenebenzodioxazole) (PBO) fibers. This invention does not impose any special limitations on the specifications of the PTFE fibers and reinforcing fibers; commercially available products well-known in the art can be used.

[0024] In this invention, the mass fraction of polytetrafluoroethylene fiber in the fiber fabric can be 30-50%, and in the examples it can be 49%, 41% or 33.5%.

[0025] In this invention, the preferred conditions for electrostatic spraying include: a voltage preferably of 10-18 kV, more preferably 14-17 kV, and in this embodiment, 17 kV. The constant propulsion speed of the polytetrafluoroethylene dispersion is preferably 0.1-1.0 mL / h, more preferably 0.2-0.8 mL / h, and in this embodiment, 0.3 mL / h or 0.5 mL / h. The receiving distance between the electrostatic spraying needle and the receiving device is preferably 10-30 cm, more preferably 15-20 cm, and in this embodiment, 17 cm or 15 cm. The left-right movement speed of the electrostatic spraying needle is preferably 5-50 mm / s, more preferably 5-20 mm / s, and in this embodiment, 10 mm / s. The rotation speed of the receiving roller is preferably 100-400 r / min, more preferably 200-300 r / min, and in this embodiment, 200 r / min. In this invention, electrostatic spraying technology is a technique that uses a high-voltage electric field to atomize liquid into tiny droplets, featuring controllable size, uniform deposition, and high material utilization. This invention achieves a uniform coating of PTFE nanoparticles on the surface of fiber fabric by adjusting electrostatic spraying process parameters, thereby accelerating the formation of a transfer film on the mating surface. The rolling effect and low coefficient of friction of the PTFE nanoparticles improve the tribological properties of the self-lubricating fabric surface, effectively reducing the starting friction torque of the self-lubricating composite material and avoiding the aggravated wear or failure of the lubricating material due to excessive starting friction torque.

[0026] In this invention, the preferred mass of the electrostatically sprayed polytetrafluoroethylene nanoparticle layer is 0.1 × 10⁻⁶. -4 ~5×10 -4 g / cm 2More preferably 0.5×10 -4 ~4.5×10 -4 g / cm 2 Further preferred is 1×10 -4 ~4×10 -4 g / cm 2 A further preferred value is 1.5 × 10⁻⁶. -4 ~3.5×10 -4 g / cm 2 In the example, it can be 0.59×10 -4 g / cm 2 1.39×10 -4 g / cm 2 Or 2.06×10 -4 g / cm 2 .

[0027] After obtaining the electrostatic sprayed polytetrafluoroethylene composite fabric, the present invention performs plasma etching treatment on the electrostatic sprayed polytetrafluoroethylene composite fabric, and then impregnates and dries it with a resin solution to obtain a self-lubricating fabric prepreg.

[0028] In this invention, the plasma etching conditions preferably include: a power of 20-200W, more preferably 50-100W, and in the embodiments, 100W, 80W, or 50W; and a time of 1-30 minutes, more preferably 5-15 minutes, and in the embodiments, 5 minutes, 10 minutes, or 15 minutes. In this invention, the plasma etching treatment can improve the surface activity of PTFE, thereby enhancing the interfacial bonding strength between PTFE nanoparticles and the resin.

[0029] In this invention, after the plasma etching process, an electrostatically sprayed polytetrafluoroethylene (PTFE) composite fabric is obtained. After obtaining the plasma-treated electrostatically sprayed PTFE composite fabric, this invention impregnates and dries the plasma-treated electrostatically sprayed PTFE composite fabric with a resin solution to obtain a self-lubricating fabric prepreg.

[0030] In this invention, the resin solution is preferably a phenolic resin solution. The resin content in the phenolic resin solution is preferably 5-20% by mass, more preferably 10-15%.

[0031] In this invention, the impregnation-drying process is preferably repeated, that is, the plasma-treated electrostatic sprayed PTFE composite fabric is impregnated in a resin solution and then dried; the drying temperature is preferably 30~70℃, more preferably 40~50℃, and in the embodiment, it can be 45℃. In this invention, the impregnation and drying steps are repeated, and there is no special requirement for the number of times the impregnation-drying process is repeated. The impregnation is performed until the mass percentage of the plasma-treated electrostatic sprayed PTFE composite fabric in the self-lubricating fabric prepreg is preferably 60~90%, more preferably 65~85%, and even more preferably 70~80%, and in the embodiment, it can be 75±5%.

[0032] After obtaining the self-lubricating fabric prepreg, the present invention cures and molds the self-lubricating fabric prepreg to obtain the low starting friction torque self-lubricating fabric composite material.

[0033] In this invention, the curing conditions preferably include: a curing pressure of 0.1~0.5 MPa, more preferably 0.2~0.4 MPa, and in the embodiment, 0.3 MPa. The curing temperature is preferably 160~200℃, more preferably 170~190℃, and in the embodiment, 180℃. The curing time is preferably 1~2 h, more preferably 1.5~2 h, and in the embodiment, 2 h.

[0034] This invention provides a low-starting-friction-torque self-lubricating fabric composite material prepared by the preparation method described above. The low-starting-friction-torque self-lubricating fabric composite material provided by this invention comprises a plasma-treated electrostatic sprayed polytetrafluoroethylene composite fabric and a resin material laminated on the plasma-treated electrostatic sprayed polytetrafluoroethylene composite fabric. The resin material can be phenolic resin.

[0035] In this invention, the maximum starting friction torque of the low starting friction torque self-lubricating fabric composite material is <6.5 lbf, specifically 5.9 lbf, 6.4 lbf or 5.7 lbf in the embodiments.

[0036] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0037] Example 1 (1) Using polyaryl ester fiber and polytetrafluoroethylene fiber as weaving fibers, a twill weave is used to obtain a polyaryl ester fiber / polytetrafluoroethylene fiber blended fabric, wherein the mass fraction of polytetrafluoroethylene fiber in the polyaryl ester fiber / polytetrafluoroethylene fiber blended fabric is 49%. A PTFE concentrate with a solid content of 60% is mixed and diluted with deionized water at a volume ratio of 1:2, and after ultrasonic vibration for 120 min, a PTFE dispersion is obtained (where the particle size of PTFE is 0.1~0.5μm). The PTFE dispersion is used as an electrostatic spraying solution. Under the action of a 17kV high voltage electric field, the receiving distance is 17cm, the advancing speed is 0.3mL / h, the left and right moving speed of the electrostatic spraying needle is 10mm / s, and the rotation speed of the receiving roller is 200r / min. PTFE nanoparticles are uniformly sprayed onto the fabric to obtain an electrostatic sprayed PTFE composite fabric. The mass of the obtained electrostatic sprayed PTFE nanoparticle layer is 0.59×10⁻⁶. -4 g / cm 2 .

[0038] (2) The obtained electrostatic sprayed PTFE composite fabric was subjected to plasma treatment at a power of 100W for 5 minutes. The plasma-treated composite fabric was then immersed in a phenolic resin solution (resin content of 15%) and dried in an oven at 45°C. The above immersion-drying process was repeated until the mass fraction of the electrostatic sprayed PTFE composite fabric in the obtained self-lubricating fabric composite prepreg reached 75±5%, and the self-lubricating composite fabric prepreg was obtained.

[0039] (3) Phenolic resin was used to bond the self-lubricating composite fabric prepreg to the surface of the metal substrate and cured at 0.3MPa and 180℃ for 2h to obtain a self-lubricating composite fabric material with low starting friction torque.

[0040] Example 2 (1) Using aramid III fiber and polytetrafluoroethylene fiber as weaving fibers, a satin weave was used to obtain an aramid III fiber / polytetrafluoroethylene fiber blended fabric, wherein the mass fraction of polytetrafluoroethylene fiber in the aramid III fiber / polytetrafluoroethylene fiber blended fabric was 41%. A PTFE concentrate with a solid content of 60% was mixed and diluted with deionized water at a volume ratio of 1:1, and after ultrasonic vibration for 120 min, a PTFE dispersion was obtained (where the particle size of PTFE was 0.1~0.5μm). The PTFE dispersion was used as an electrostatic spraying solution. Under the action of a 17kV high-voltage electric field, the receiving distance was 15cm, the propulsion speed was 0.5mL / h, the left and right movement speed of the electrostatic spraying needle was 10mm / s, and the rotation speed of the receiving roller was 200r / min. PTFE nanoparticles were uniformly sprayed onto the fabric to obtain an electrostatic sprayed PTFE composite fabric. The mass of the obtained electrostatic sprayed PTFE nanoparticle layer was 1.39×10⁻⁶. -4g / cm 2 .

[0041] (2) The obtained electrostatic sprayed PTFE composite fabric was subjected to plasma treatment at a power of 80W for 10 minutes. The plasma-treated composite fabric was then immersed in a phenolic resin solution (resin content of 15%) and dried in an oven at 45°C. The above immersion-drying process was repeated until the mass fraction of the electrostatic sprayed PTFE composite fabric in the obtained self-lubricating fabric composite prepreg reached 75±5%, and the self-lubricating composite fabric prepreg was obtained.

[0042] (3) Phenolic resin was used to bond the self-lubricating composite fabric prepreg to the surface of the metal substrate and cured at 0.3MPa and 180℃ for 2h to obtain a self-lubricating composite fabric material with low starting friction torque.

[0043] Example 3 (1) Using PBO fiber and polytetrafluoroethylene fiber as weaving fibers, a satin weave was used to obtain a PBO fiber / polytetrafluoroethylene fiber blended fabric, wherein the mass fraction of polytetrafluoroethylene fiber in the PBO fiber / polytetrafluoroethylene fiber blended fabric was 33.5%. A PTFE concentrate with a solid content of 60% was mixed and diluted with deionized water at a volume ratio of 1:0.5, and after ultrasonic vibration for 120 min, a PTFE dispersion was obtained (where the particle size of PTFE was 0.1~0.5μm). The PTFE dispersion was used as an electrostatic spraying solution. Under the action of a 17kV high-voltage electric field, the receiving distance was 15cm, the advancing speed was 0.5mL / h, the left and right moving speed of the electrostatic spraying needle was 10mm / s, and the rotation speed of the receiving roller was 200r / min. PTFE nanoparticles were uniformly sprayed onto the fabric to obtain an electrostatic sprayed PTFE composite fabric. The mass of the obtained electrostatic sprayed PTFE nanoparticle layer was 2.06×10⁻⁶. -4 g / cm 2 .

[0044] (2) The obtained electrostatic sprayed PTFE composite fabric was subjected to plasma treatment at a power of 50W for 15 minutes. The plasma-treated composite fabric was then immersed in a phenolic resin solution (resin content of 15%) and dried in an oven at 45°C. The above immersion-drying process was repeated until the mass fraction of the electrostatic sprayed PTFE composite fabric in the obtained self-lubricating fabric composite prepreg reached 75±5%, and the self-lubricating composite fabric prepreg was obtained.

[0045] (3) Phenolic resin was used to bond the self-lubricating composite fabric prepreg to the surface of the metal substrate and cured at 0.3MPa and 180℃ for 2h to obtain a self-lubricating composite fabric material with low starting friction torque.

[0046] Comparative Example 1 Compared with Example 1, the specific preparation method is as follows: (1) Using polyaryl ester fiber and polytetrafluoroethylene fiber as weaving fibers, a twill weave is used to obtain a polyaryl ester fiber / polytetrafluoroethylene fiber blended fabric.

[0047] (2) The polyaryl ester fiber / polytetrafluoroethylene fiber blended fabric is impregnated in a phenolic resin solution (the resin content is 15%), and then dried in an oven at 45°C. The above impregnation-drying process is repeated until the mass fraction of the polyaryl ester fiber / polytetrafluoroethylene fiber blended fabric in the self-lubricating fabric prepreg reaches 75±5%, and the self-lubricating composite fabric prepreg is obtained.

[0048] (3) Phenolic resin was used to bond the self-lubricating composite fabric prepreg to the surface of the metal substrate and cured at 0.3 MPa and 180°C for 2 hours to obtain the self-lubricating fabric composite material (non-electrostatic sprayed PTFE nanoparticle layer).

[0049] Comparative Example 2 Compared with Example 2, the specific preparation method is as follows: (1) Using aramid III fiber and polytetrafluoroethylene fiber as weaving fibers, a satin weave is used to obtain an aramid III fiber / polytetrafluoroethylene fiber blended fabric.

[0050] (2) The aramid III fiber / polytetrafluoroethylene fiber blended fabric is impregnated in a phenolic resin solution (the resin content is 15%), and then dried in an oven at 45°C. The above impregnation-drying process is repeated until the mass fraction of the aramid III fiber / polytetrafluoroethylene fiber blended fabric in the self-lubricating fabric prepreg reaches 75±5%, and the self-lubricating composite fabric prepreg is obtained.

[0051] (3) Phenolic resin was used to bond the self-lubricating composite fabric prepreg to the surface of the metal substrate and cured at 0.3 MPa and 180°C for 2 hours to obtain the self-lubricating fabric composite material (non-electrostatic sprayed PTFE nanoparticle layer).

[0052] Comparative Example 3 Compared with Example 3, the specific preparation method is as follows: (1) Using PBO fiber and polytetrafluoroethylene fiber as weaving fibers, a satin weave is used to obtain a PBO fiber / polytetrafluoroethylene fiber blended fabric.

[0053] (2) The PBO fiber / polytetrafluoroethylene fiber blended fabric is impregnated in a phenolic resin solution (the resin content is 15%), and then dried in an oven at 45°C. The above impregnation-drying process is repeated until the mass fraction of the PBO fiber / polytetrafluoroethylene fiber blended fabric in the self-lubricating fabric prepreg reaches 75±5%, and the self-lubricating composite fabric prepreg is obtained.

[0054] (3) Phenolic resin was used to bond the self-lubricating composite fabric prepreg to the surface of the metal substrate and cured at 0.3 MPa and 180°C for 2 hours to obtain the self-lubricating fabric composite material (non-electrostatic sprayed PTFE nanoparticle layer).

[0055] Performance testing: Figure 1 The image shown is a field emission scanning electron microscope (SEM) image of PTFE nanoparticles sprayed in Example 1. By adjusting the electrostatic spraying process parameters, PTFE nanoparticles can be deposited more uniformly on the fabric surface.

[0056] The tribological properties of the self-lubricating fabric composites prepared in Examples 1-3 and Comparative Examples 1-3 were tested. The test conditions were: pressure 55 MPa, sliding friction linear velocity 0.24 m / s, time 120 min, and room temperature. An F-1506-330 multi-specimen tribological testing machine was used, with 45# steel with a diameter of 2 mm as the friction pair. The test results are shown in Table 1. As can be seen from Table 1, constructing a PTFE nanoparticle lubricating layer on the surface of the fiber fabric through electrostatic spraying technology is beneficial to reducing the coefficient of friction and wear rate of the self-lubricating fabric composite, thereby improving its lubrication performance to a certain extent.

[0057] Figure 2 The bar chart shows the maximum starting friction torque for Comparative Examples 1-3 and Examples 1-3. Figure 3 , Figure 4 and Figure 5 The figures show the friction torque curves for the comparative examples and the embodiments. The results show that the electrostatically sprayed PTFE nanoparticle lubricating layer deposited on the surface of the self-lubricating fabric composite material can effectively reduce the starting friction torque of the composite material during the break-in and wear stages. The maximum starting friction torque for Comparative Example 1 was 7.9 lbf, while that for Example 1 was 5.9 lbf, a decrease of 25.3%. The maximum starting friction torques for Comparative Examples 2 and 3 were 11.8 lbf and 8.9 lbf, respectively, while those for Examples 2 and 3 were 6.4 lbf and 5.7 lbf, respectively, representing decreases of 45.8% and 36%. Furthermore, the friction torque curves show that the friction curves of the self-lubricating fabric composite material containing the electrostatically sprayed PTFE nanoparticle layer are more stable, indicating that the electrostatically sprayed PTFE nanoparticle layer improves the stability of the self-lubricating fabric composite material during the friction and wear process.

[0058] Table 1. Tribological and wear performance test results of the self-lubricating fabric composites prepared in Examples 1-3 and Comparative Examples 1-3.

[0059] As can be seen from the above embodiments, the present invention is based on the fact that PTFE nanoparticles have extremely low friction coefficient and high specific surface area. By using electrostatic spraying technology, PTFE nanoparticles are uniformly deposited on the surface of fiber fabric, which increases the PTFE content on the fabric surface and accelerates the formation of transfer film on the mating surface. The rolling effect and low friction coefficient of PTFE nanoparticles can improve the tribological properties of the self-lubricating fabric surface, thereby effectively reducing the starting friction torque of the self-lubricating fabric composite material in the running-in and wear stage, making it exhibit good running-in performance, and reducing the wear amount and friction coefficient of the self-lubricating fabric composite material to a certain extent.

[0060] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a self-lubricating fabric composite material with low starting friction torque, characterized in that, Includes the following steps: Using polytetrafluoroethylene dispersion as a spray solution, polytetrafluoroethylene nanoparticles are deposited on the surface of fiber fabric by electrostatic spraying to form an electrostatic sprayed polytetrafluoroethylene nanoparticle layer, thus obtaining an electrostatic sprayed polytetrafluoroethylene composite fabric. The electrostatic sprayed polytetrafluoroethylene composite fabric is subjected to plasma etching treatment, and then impregnated and dried with resin solution to obtain a self-lubricating fabric prepreg. The self-lubricating fabric prepreg is cured and molded to obtain the low starting friction torque self-lubricating fabric composite material.

2. The preparation method according to claim 1, characterized in that, The method for preparing the polytetrafluoroethylene dispersion includes: mixing polytetrafluoroethylene concentrate and deionized water and then subjecting the mixture to ultrasonic treatment to obtain the polytetrafluoroethylene dispersion; the solid content of polytetrafluoroethylene in the polytetrafluoroethylene concentrate is 50-60%, and the volume ratio of the polytetrafluoroethylene concentrate to deionized water is 1:0.1-5; the ultrasonic treatment time is 30-200 min.

3. The preparation method according to claim 1 or 2, characterized in that, The polytetrafluoroethylene particles in the polytetrafluoroethylene dispersion have a particle size of 0.1~0.5μm.

4. The preparation method according to claim 1, characterized in that, The fiber fabric is a blend of polytetrafluoroethylene fiber and reinforcing fiber, wherein the reinforcing fiber includes one or more of aramid fiber, liquid crystal fiber, polyimide fiber, polyarylate fiber and poly(p-phenylenebenzodioxazole) fiber.

5. The preparation method according to claim 1, characterized in that, The conditions for electrostatic spraying include: a voltage of 10~18 kV, a constant propulsion speed of PTFE dispersion of 0.1~1.0 mL / h, a receiving distance of 10~30 cm between the electrostatic spraying needle and the receiving device, a left-right movement speed of the electrostatic spraying needle of 5~50 mm / s, and a rotation speed of the receiving roller of 100~400 r / min.

6. The preparation method according to claim 1 or 5, characterized in that, The mass of the electrostatically sprayed polytetrafluoroethylene nanoparticle layer is 0.1 × 10⁻⁶. -4 ~5×10 -4 g / cm 2 .

7. The preparation method according to claim 1, characterized in that, The conditions for the plasma etching process include: power of 20~200W and time of 1~30min.

8. The preparation method according to claim 1, characterized in that, After the plasma etching process is completed, the plasma-treated electrostatic sprayed polytetrafluoroethylene composite fabric is obtained, and the mass percentage of the plasma-treated electrostatic sprayed polytetrafluoroethylene composite fabric in the self-lubricating fabric prepreg is 60~90%.

9. The preparation method according to claim 1, characterized in that, The curing conditions include: curing pressure of 0.1~0.5MPa, curing temperature of 160~200℃, and curing time of 1~2h.

10. The low starting friction torque self-lubricating fabric composite material prepared by the preparation method according to any one of claims 1 to 9.

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