CN111844968A - A kind of preparation method of polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material - Google Patents

Abstract

The invention discloses a polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric liner material and a preparation method thereof, polytetrafluoroethylene fibers are used as warp yarns, polyimide fibers are used as weft yarns to weave a fabric, the fabric is subjected to air plasma modification treatment, and then is soaked and dried in a polyimide solution, and the steps are repeated until the mass fraction of polyimide resin in the fabric liner material reaches the target requirement; and finally, sticking the impregnated fabric gasket on the surface of a specified metal base material by using polyimide resin, and carrying out curing reaction at a specific temperature and pressure to obtain the self-lubricating fabric gasket material. The self-lubricating fabric liner material synthesized by the invention has the advantages of high temperature resistance, high bearing capacity, low friction, strong interface adhesion and the like, is suitable for extreme service working conditions such as high temperature and high speed, and greatly expands the application range of the self-lubricating joint bearing in the field of lubrication of high-end equipment.

Description

A kind of polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material Preparation

technical field

The invention relates to a preparation method of a polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric lining material, which is mainly used for the processing of self-lubricating spherical plain bearings under extreme service conditions such as high temperature and high speed, and belongs to composite materials The technical field of preparation and solid lubrication.

Background technique

Self-lubricating spherical plain bearing is a spherical plain bearing mainly composed of an outer ring with an inner spherical surface, an inner ring with an outer spherical surface and a self-lubricating gasket. Because of its compact structure, strong bearing capacity, corrosion resistance and maintenance-free, etc. It is widely used in aerospace, precision machinery and other high-end equipment lubrication fields. As a key component of self-lubricating spherical plain bearings, self-lubricating fabric backing material directly affects the service behavior and service life of self-lubricating spherical plain bearings. The self-lubricating fabric liner is made of a thin-layer fabric woven with polytetrafluoroethylene fibers and other high-performance reinforcing fibers mixed with polymer resin, making it both have the excellent lubricating properties of polytetrafluoroethylene fibers and the outstanding reinforcement fibers. carrying capacity.

In recent years, the rapid development of construction machinery and equipment technology has put forward higher requirements for the friction and wear properties of self-lubricating fabric backing materials, such as requiring fabric backing materials to be stable and long-lasting under extreme working conditions such as high temperature and high speed. run. In previous studies, PTFE/aramid phenolic resin-based fabric lining materials have been widely used because of their excellent anti-friction and wear resistance properties, but the thermal properties of this lining material are poor, and it is difficult to meet high temperature, Requirements for extreme working conditions such as high speed. Therefore, improving the high temperature resistance of self-lubricating fabric liners is of great significance, but also faces many challenges.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method and application of a polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material.

1. Preparation of self-lubricating fabric backing material

The preparation of the self-lubricating fabric lining material of the present invention uses polytetrafluoroethylene fibers as warp yarns and polyimide fibers as weft yarns to weave fabrics. The fabrics are first modified by air plasma, and then dipped in polyimide solution. , drying, and repeated impregnation and drying until the mass fraction of polyimide resin in the fabric reaches the target requirement; then the impregnated fabric liner is pasted on the surface of the metal substrate with polyimide resin, and finally cured After the reaction, a self-lubricating fabric backing material was obtained.

The weave structure of the woven fabric is one of plain weave, twill weave and satin weave, or a combination of several weaves.

The time of the air plasma treatment is 5-20 min, and the power is 50-200 W.

The mass fraction of the polyimide resin in the fabric backing material is 20-30%.

The metal base material is one of 9Cr18Mo, 9Cr18MoV, 9Cr18, 4Cr13 and 17-4PH.

The curing reaction, under the condition of applying a pressure of 0.1-0.3 MPa, goes through four stages of 100, 150, 200, and 265 °C in sequence, and the holding time of each stage is 30-60 min, and the heating rate is 5-10 °C/min.

2. Friction and wear performance test

1. High temperature tribological properties

Test method: Xuanwu No. 3 friction and wear testing machine was used, and No. 45 steel with a diameter of 2 mm was used as the friction pair. Under certain conditions such as sliding speed, applied load, and test time, the friction was adjusted by a heating furnace equipped outside the friction pair. The friction test was carried out at the ambient temperature of the test. The coefficient of friction is automatically output after processing the collected data through a connected computer. Using a digital altimeter to measure the wear depth of the self-lubricating fabric pad material, and then calculate the wear volume of the fabric pad. The specific wear rate of the fabric backing material was calculated using the formula K=ΔV/P∙L, K─specific wear rate; ΔV─wear volume; P─applied load; L─sliding distance.

Figure 1 is a bar graph (b) of the coefficient of friction (a) and wear rate of PTFE/polyimide fabric-polyimide resin-based fabric pads as a function of ambient temperature. The results in Figure 1(a) show that the self-lubricating fabric liner can maintain excellent lubricating performance in the test temperature range, and with the increase of the ambient temperature, the friction coefficient of the self-lubricating fabric liner material shows a downward trend. When the test environment temperature is 335 ℃, the friction coefficient of the fabric backing material is 0.0453, showing excellent high temperature lubrication performance. The results in Figure 1(b) show that the specific wear rate of the self-lubricating fabric liner shows an obvious upward trend with the increase of the ambient temperature, but it can maintain outstanding wear resistance in the test temperature range. When the test environment temperature was 335 ℃, the wear rate of the fabric backing material was 22.1×10 ^-14 m ³ · (N · m) ^-1 , which remained at a low level, showing excellent high temperature wear resistance.

2. High-speed tribological properties

Test method: Xuanwu No. 3 friction and wear testing machine was used, and No. 45 steel with a diameter of 2 mm was used as the friction pair. Under the conditions of room temperature and certain applied load and test time, the sliding speed of the friction test was adjusted to explore the effect of sliding speed on the friction test. Influence of tribological properties of fabric pads. The coefficient of friction is automatically output after processing the collected data through a connected computer. Using a digital altimeter to measure the wear depth of the self-lubricating fabric pad material, and then calculate the wear volume of the fabric pad. The specific wear rate of the fabric backing material was calculated using the formula K=ΔV/P∙L, K─specific wear rate; ΔV─wear volume; P─applied load; L─sliding distance.

Figure 2 is a bar graph (b) of the coefficient of friction (a) and wear rate of the PTFE/polyimide fabric-polyimide resin-based fabric pad as a function of sliding speed. The results in Fig. 2(a) show that the self-lubricating fabric liner can maintain excellent lubricating performance in the test sliding speed range, and with the increase of sliding speed, the friction coefficient of the self-lubricating fabric liner material shows a slight downward trend. When the sliding speed is 2.73m/s, the friction coefficient of the fabric backing material is 0.1322, which remains at a low level. The results in Fig. 2(b) show that the specific wear rate of the self-lubricating fabric liner shows a clear downward trend with the increase of the sliding speed. When the test sliding speed is 2.73m/s, the specific wear rate of the fabric backing material is 2.3×10 ^-14 m ³ · (N · m) ^-1 , which is kept at a low level, showing excellent high-speed tribology performance.

To sum up, the present invention uses polyimide fibers as reinforcing fibers, and blends and weaves with polytetrafluoroethylene fibers to prepare polytetrafluoroethylene/polyimide fabric-polyimide resin-based self-lubricating fabric pads The material has good wettability, which makes the interfacial adhesion of the fabric backing material good. At the same time, because the polyimide fiber and polyimide resin used have outstanding thermal stability, they endow the self-lubricating fabric backing material with excellent high temperature and high speed tribological properties, so it is suitable for extreme service conditions such as high temperature and high speed. conditions, which greatly expands the application scope of self-lubricating spherical plain bearings in the field of high-end equipment lubrication.

Description of drawings

Figure 1 is a histogram of the friction coefficient and wear rate of PTFE/polyimide fabric-polyimide resin-based fabric liner as a function of ambient temperature (0.26 m/s, 12.5 MPa).

Figure 2 is a histogram of the friction coefficient and wear rate of the PTFE/polyimide fabric-polyimide resin-based fabric pad as a function of sliding speed (room temperature, 12.5 MPa).

Detailed ways

The polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material of the present invention and its preparation method and application will be further described below through specific examples.

Example 1

The broken twill fabric was woven with polytetrafluoroethylene fiber as the warp yarn and polyimide fiber as the weft yarn; the fabric was first modified by air plasma (10 min, 100 W), and then dipped in polyimide solution, Drying, and repeated impregnation and drying until the mass fraction of polyimide resin in the fabric reaches 30 wt%; then the impregnated fabric liner is pasted on the surface of the 9Cr18Mo metal substrate with polyimide resin, and finally Under the condition of 0.2 MPa pressure, successively increased to 100 °C for 20 min and held for 30 min, 10 min to 150 °C and held for 60 min, 10 min to 200 °C and held for 60 min, 10 min to 265 °C and held for 120 min. Min curing reaction, produced self-lubricating fabric backing material.

The tribological properties of the self-lubricating fabric pads prepared above were evaluated by the Xuanwu No. 3 friction and wear tester. Under the conditions of 0.26 m/s, 12.5 MPa, the friction coefficient and wear rate in a high temperature environment of 335 ℃ were 0.051, 25 ×10 ^-14 m ³ · (N·m) ^-1 .

Example 2

The satin fabric was woven with polytetrafluoroethylene fiber as warp yarn and polyimide fiber as weft yarn; the fabric was first modified by air plasma (8 min, 120 W), and then dipped and dried in polyimide solution. , and repeated impregnation and drying until the mass fraction of polyimide resin in the fabric backing material reached 25 wt%; then the impregnated fabric was pasted on the surface of 9Cr18Mo metal substrate with polyimide resin, and finally at 0.2 Under MPa pressure conditions, successively increased to 100 °C for 20 min and held for 30 min, 10 min to 150 °C and held for 60 min, 10 min to 200 °C and held for 60 min, 10 min to 265 °C and held for 120 min The curing reaction of self-lubricating fabric backing material is obtained.

The tribological properties of the self-lubricating fabric pads prepared above were evaluated by the Xuanwu No. 3 friction and wear testing machine. Under the conditions of 0.26 m/s and 12.5 MPa, the friction coefficient and wear rate in a high temperature environment of 335 ℃ were 0.042, 19 ×10 ^-14 m ³ · (N·m) ^-1 .

Example 3

The plain weave fabric was woven with polytetrafluoroethylene fiber as warp yarn and polyimide fiber as weft yarn; the fabric was first modified by air plasma (10 min, 100 W), and then dipped and dried in polyimide solution. , and repeated impregnation and drying until the mass fraction of polyimide resin in the fabric pad material reaches 30 wt%; then the impregnated fabric pad is pasted on the surface of the 17-4PH metal substrate with polyimide resin , and finally, under the pressure of 0.2 MPa, successively increased to 100 °C for 20 min and held for 60 min, 10 min to 150 °C and held for 120 min, 10 min to 200 °C and held for 120 min, 10 min to 265 °C and then held at 265 °C for 10 min. The curing reaction was kept for 150 min to obtain a self-lubricating fabric backing material.

The tribological properties of the self-lubricating fabric linings prepared above were evaluated by the Xuanwu No. 3 friction and wear testing machine. Under the conditions of 0.26 m/s and 12.5 MPa, the friction coefficient and wear rate in a high temperature environment of 335 ℃ were 0.06 and 23, respectively. ×10 ^-14 m ³ · (N·m) ^-1 .

Example 4

The twill fabric was woven with polytetrafluoroethylene fiber as warp yarn and polyimide fiber as weft yarn; the fabric was first modified by air plasma (5 min, 200 W), and then dipped and dried in polyimide solution. , repeated impregnation and drying until the mass fraction of polyimide resin in the fabric pad material reached 20 wt%; then the impregnated fabric pad was pasted on the surface of the 17-4PH metal substrate with polyimide resin, Finally, under the condition of 0.25 MPa pressure, the temperature was successively increased to 100 °C for 25 min and held for 30 min, 15 min to 150 °C and held for 60 min, 15 min to 200 °C and held for 60 min, 15 min to 265 °C and held for 15 min. After 120 min of curing reaction, a self-lubricating fabric backing material was prepared.

The tribological properties of the self-lubricating fabric pads prepared above were evaluated by the Xuanwu No. 3 friction and wear tester. Under the conditions of 0.26 m/s, 12.5 MPa, the friction coefficient and wear rate in a high temperature environment of 335 ℃ were 0.039, 21 ×10 ^-14 m ³ · (N·m) ^-1 .

Example 5

The twill fabrics were woven with polytetrafluoroethylene fibers as warp yarns and polyimide fibers as weft yarns. The fabrics were first modified by air plasma (5 min, 200 W), and then dipped and dried in polyimide solution. , and repeated impregnation and drying until the mass fraction of polyimide resin in the fabric pad material reached 20 wt%; then the impregnated fabric pad was pasted on the surface of the 9Cr18 metal substrate with polyimide resin, and finally Under the condition of 0.25 MPa pressure, successively increased to 100 °C for 25 min and held for 30 min, 15 min to 150 °C and held for 60 min, 15 min to 200 °C and held for 60 min, 15 min to 265 °C and held for 120 min. Min curing reaction, produced self-lubricating fabric backing material.

The tribological properties of the self-lubricating fabric liner prepared above were evaluated by the Xuanwu No. 3 friction and wear tester. ^-14 m ³ ·(N·m) ^-1 .

Claims (6)

1. a preparation method of polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material is to use polytetrafluoroethylene fiber as warp yarn, polyimide fiber as weft yarn woven fabric, and the fabric is first warped by air plasma body modification treatment, then dipping and drying in polyimide solution, and repeating dipping and drying until the mass fraction of polyimide resin in the fabric reaches the target requirement; The fabric liner is pasted on the surface of the metal substrate, and finally undergoes a curing reaction to obtain a self-lubricating fabric liner material. 2. the preparation method of polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material as claimed in claim 1, is characterized in that: the structure of described woven fabric is a kind of in plain weave, twill weave and satin weave Or use a combination of several organizations. 3. the preparation method of polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material as claimed in claim 1, is characterized in that: the time of air plasma treatment is 5～20 min, and power is 50～200 W. 4. The preparation method of the polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material according to claim 1, wherein the mass fraction of the polyimide resin in the fabric is 20-30%. 5. The preparation method of the polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material according to claim 1, wherein the metal base material is that the metal base material is 9Cr18Mo, 9Cr18MoV, 9Cr18, 4Cr13, 17 One of -4PH. 6. The preparation method of the polyimide fiber/polytetrafluoroethylene fiber self-lubricating fabric backing material according to claim 1, characterized in that: in the curing reaction, the applied pressure is 0.1-0.3 MPa, and the pressure of the curing reaction is 0.1-0.3 MPa. The temperature went through four stages of 100, 150, 200, and 265 °C, the holding time of each stage was 30-60 min, and the heating rate was 5-10 °C/min.

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