CN111333982B - A kind of polytetrafluoroethylene friction material and its preparation method and application - Google Patents

Abstract

The invention provides a polytetrafluoroethylene friction material, a preparation method and application thereof, and relates to the technical field of friction materials. The polytetrafluoroethylene friction material of the present invention includes the following raw materials in parts by mass: 65-80 parts of polytetrafluoroethylene, 1-5 parts of nano-boron nitride, 5-15 parts of molybdenum disulfide, and 1-5 parts of nano-zirconia , 1-5 parts of carbon quantum dots, and 1-5 parts of lamellar nano-Ti ₃ C ₂ . The invention adds lamella nano Ti ₃ C ₂ , and the unique two-dimensional layered structure of lamella nano Ti ₃ C ₂ makes it have excellent tribological properties, and with other components, the obtained PTFE friction material can be significantly improved Start-stop characteristics of large ultrasonic motors.

Description

A kind of polytetrafluoroethylene friction material and its preparation method and application

technical field

The invention relates to the technical field of friction materials, in particular to a polytetrafluoroethylene friction material and a preparation method and application thereof.

Background technique

Ultrasonic motor is a new type of precision-driven micro-motor. Through energy conversion and motion transmission, it applies force or torque to the load to achieve the purpose of controlling the precise movement/positioning of the load. As a precision drive component, ultrasonic motors are widely used in aerospace, weapon equipment and robotics fields, promoting the development of equipment in the direction of high precision, high efficiency, high reliability, intelligence and light weight, and its influence on national science and technology and national defense deterrence power has an important impact.

A large number of researchers have found that the ultrasonic motor cannot be started normally when it is used, especially after being placed for a period of time, this problem seriously hinders the reliability of the ultrasonic motor, so its development in aerospace, weaponry and other fields has been seriously affected. constraints. The above problems are more pronounced in large ultrasonic motors (150mm in diameter). An important issue that affects the start-stop characteristics of ultrasonic motors is the friction material. The traditional fillers for improving friction materials, such as carbon fiber, aramid fiber, and silica lime, have a single function, and the effect of improving the start-stop performance of the ultrasonic motor is not good.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a polytetrafluoroethylene friction material and a preparation method and application thereof. The polytetrafluoroethylene friction material of the present invention can significantly improve the start-stop characteristics of large ultrasonic motors.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a polytetrafluoroethylene friction material, comprising the following raw materials in parts by mass: 65-80 parts of polytetrafluoroethylene, 1-5 parts of nano-boron nitride, 5-15 parts of molybdenum disulfide, and nano-zirconia 1 to 5 parts, 1 to 5 parts of carbon quantum dots, and 1 to 5 parts of lamellar nano-Ti ₃ C ₂ .

Preferably, the preparation raw materials include 70-80 parts of polytetrafluoroethylene, 2-5 parts of nano-boron nitride, 7-15 parts of molybdenum disulfide, 3-5 parts of nano-zirconia, 2-5 parts of carbon quantum dots, lamellae 2-4 parts of nano-Ti ₃ C ₂ .

Preferably, the single-layer thickness of the lamellar nano-Ti ₃ C ₂ is 80-100 nm.

Preferably, the particle size of the polytetrafluoroethylene is 65-75 μm; the sheet diameter of the nano-boron nitride is 0.3-2 nm; the sheet diameter of the molybdenum disulfide is 15-25 μm; The particle size is 20-40 nm; the particle size of the carbon quantum dots is 3-5 nm.

The present invention provides the preparation method of the polytetrafluoroethylene friction material described in the above scheme, comprising the following steps:

The preparation raw materials are mixed, and the obtained mixed materials are sequentially pressed and sintered to obtain a polytetrafluoroethylene friction material.

Preferably, the pressing pressure is 70-100 MPa, and the time is 3-5 min.

Preferably, the sintering temperature is 365-375° C., and the holding time is 90-150 min.

Preferably, the mixing process is as follows: each preparation raw material is dispersed in ethanol or acetone, and the mixture is obtained after drying.

The present invention provides the application of the polytetrafluoroethylene friction material in the above scheme or the polytetrafluoroethylene friction material prepared by the preparation method in the above scheme in an ultrasonic motor.

Preferably, the diameter of the ultrasonic motor is more than 150 mm.

The invention provides a polytetrafluoroethylene friction material, comprising the following raw materials in parts by mass: 65-80 parts of polytetrafluoroethylene, 1-5 parts of nano-boron nitride, 5-15 parts of molybdenum disulfide, and nano-zirconia 1 to 5 parts, 1 to 5 parts of carbon quantum dots, and 1 to 5 parts of lamellar nano-Ti ₃ C ₂ . The invention adds lamella nano Ti ₃ C ₂ , and the unique two-dimensional layered structure of lamella nano Ti ₃ C ₂ makes it have excellent tribological properties, and with other components, the obtained PTFE friction material can be significantly improved Start-stop characteristics of large ultrasonic motors.

Description of drawings

Fig. 1 is the scanning electron microscope photograph of lamella nano Ti ₃ C ₂ used in the present invention.

Detailed ways

The invention provides a polytetrafluoroethylene friction material, comprising the following raw materials in parts by mass: 65-80 parts of polytetrafluoroethylene, 1-5 parts of nano-boron nitride, 5-15 parts of molybdenum disulfide, and nano-zirconia 1 to 5 parts, 1 to 5 parts of carbon quantum dots, and 1 to 5 parts of lamellar nano-Ti ₃ C ₂ .

In the present invention, without special instructions, the raw materials used are all commercially available commodities well known in the art.

In parts by mass, the raw materials for the preparation of the polytetrafluoroethylene friction material provided by the present invention include 65-80 parts of polytetrafluoroethylene, preferably 70-80 parts, and more preferably 70-75 parts. In the present invention, the particle size of the polytetrafluoroethylene is preferably 65 to 75 μm, and more preferably 68 to 73 μm. In the present invention, the polytetrafluoroethylene is preferably purchased from Shandong Jinan Sanai Fu Fluorine Chemical Co., Ltd.

Based on the mass parts of the polytetrafluoroethylene, the preparation raw materials of the polytetrafluoroethylene friction material provided by the present invention include 1-5 parts of nano-boron nitride, preferably 2-5 parts, more preferably 3-5 parts . In the present invention, the sheet diameter of the nano-boron nitride is preferably 0.3-2 nm, more preferably 1-1.5 nm. In the present invention, the role of the nano-boron nitride is to improve the wear resistance of the PTFE friction material.

Based on the mass parts of the polytetrafluoroethylene, the preparation raw materials of the polytetrafluoroethylene friction material provided by the present invention include 5-15 parts of molybdenum disulfide, preferably 7-15 parts, more preferably 10-15 parts. In the present invention, the sheet diameter of the molybdenum disulfide is preferably 15 to 25 μm, and more preferably 18 to 23 μm. The present invention preferably adopts molybdenum disulfide from Beijing Dekedao Gold Technology Co., Ltd. In the present invention, the function of the molybdenum disulfide is to improve the wear resistance and the stability of the friction coefficient of the PTFE friction material.

Based on the mass parts of the polytetrafluoroethylene, the preparation raw materials of the polytetrafluoroethylene friction material provided by the present invention include 1-5 parts of nano-zirconia, preferably 3-5 parts, more preferably 4-5 parts. In the present invention, the particle size of the nano-zirconia is preferably 20-40 nm, more preferably 25-35 nm. In the present invention, the role of the nano-zirconia is to improve the load bearing capacity of the PTFE friction material, thereby increasing its service life.

Based on the mass parts of the polytetrafluoroethylene, the preparation raw materials of the polytetrafluoroethylene friction material provided by the present invention include 1-5 parts of carbon quantum dots, preferably 2-5 parts, more preferably 2-4 parts. In the present invention, the particle size of the carbon quantum dots is preferably 3 to 5 nm, more preferably 3.5 to 4.5 nm. In the present invention, the role of the carbon quantum dots is to improve the interface bonding strength between various fillers in the friction material and polytetrafluoroethylene.

Based on the mass parts of the polytetrafluoroethylene, the preparation raw materials of the polytetrafluoroethylene friction material provided by the present invention include 1-5 parts, preferably 2-4 parts, and more preferably 2.5 parts of lamellar nano-Ti ₃ C ₂ . ~ 3.5 servings. In the present invention, the single-layer thickness of the lamellar nano-Ti ₃ C ₂ is preferably 80-100 nm, more preferably 85-95 nm. In the present invention, the structure of the lamellar nano-Ti ₃ C ₂ is shown in FIG. 1 . The invention adds lamella nano Ti ₃ C ₂ , and the unique two-dimensional layered structure of lamella nano Ti ₃ C ₂ makes it have excellent tribological properties, and with other components, the obtained PTFE friction material can be significantly improved Start-stop characteristics of large ultrasonic motors.

The present invention preferably adopts carbon quantum dots, nano-boron nitride, nano-zirconia and lamellar nano-Ti ₃ C ₂ from Jiangsu Xianfeng Nano Material Technology Co., Ltd.

The present invention provides a method for preparing a polytetrafluoroethylene friction material according to the above scheme, which includes the following steps: mixing each preparation raw material, and sequentially pressing and sintering the obtained mixture to obtain a polytetrafluoroethylene friction material.

In the present invention, each preparation raw material is mixed to obtain a mixed material. In the present invention, the mixing process is preferably as follows: each preparation raw material is dispersed into ethanol or acetone, and the mixture is obtained after drying. The present invention has no special requirements for the dispersion method, and any method that can disperse uniformly can be used, such as ball milling, ultrasonic dispersion, and the like. In the present invention, there is no special requirement for the amount of the ethanol or acetone, and all the preparation raw materials can be mixed uniformly. In the present invention, the drying temperature is preferably 80-100° C., and the present invention has no special requirements for the drying time, and ethanol or acetone is preferably just evaporated to dryness.

After the mixture is obtained, the present invention compresses the mixture. In the present invention, the mixture is preferably placed in a mold for compression. The present invention has no special requirements on the shape of the mold, and those skilled in the art can select a corresponding mold according to the shape of the friction material. In the present invention, the pressing pressure is preferably 70-100 MPa, more preferably 80-100 MPa, and the time is preferably 3-5 min, more preferably 4-5 min.

After the pressing is completed, the present invention preferably demolds, and sinters the compact obtained after demolding to obtain a polytetrafluoroethylene friction material. In the present invention, the sintering is preferably carried out in an air atmosphere; the sintering temperature is preferably 365-375° C., more preferably 368-372° C., and the holding time is preferably 90-150 min, more preferably 95-145 min. In the present invention, the temperature is preferably raised from room temperature to the sintering temperature, and the present invention has no special requirements on the rate of temperature increase. After the sintering is completed, the present invention preferably freely reduces to room temperature to obtain a polytetrafluoroethylene friction material.

The present invention provides the application of the polytetrafluoroethylene friction material in the above scheme or the polytetrafluoroethylene friction material prepared by the preparation method in the above scheme in an ultrasonic motor. In the present invention, the ultrasonic motor is preferably a large ultrasonic motor (with a diameter of more than 150 mm). The present invention has no special requirements on the application mode, and an application mode well known in the art can be adopted.

The polytetrafluoroethylene friction material provided by the present invention and its preparation method and application will be described in detail below with reference to the examples, but they should not be construed as limiting the protection scope of the present invention.

Example 1

Weigh 80 g of polytetrafluoroethylene, 2 g of nano-boron nitride, 10 g of molybdenum disulfide, 3 g of nano-zirconia, 4 g of carbon quantum dots, and 1 g of lamellar nano-Ti ₃ C ₂ , mix them evenly in absolute ethanol, and mix them after drying. Put the good powder into the mold, press it for 3 minutes under the pressure of 70MPa, put it into the sintering furnace for sintering after demoulding, gradually heat up from room temperature to 365 ℃, and keep it at 365 ℃ for 90 minutes, after the sintering, it is free to cool down to obtain the polymer powder. Teflon friction material.

Example 2

Weigh 75g of polytetrafluoroethylene, 5g of nano-boron nitride, 10g of molybdenum disulfide, 5g of nano-zirconia, 3g of carbon quantum dots, and 2g of lamellar nano-Ti ₃ C ₂ , mix them well in absolute ethanol, and mix them after drying. Put the good powder into the mold, press it for 5 minutes under the pressure of 100MPa, put it into the sintering furnace for sintering after demoulding, gradually heat it up from room temperature to 375 °C, and keep it at 375 °C for 150 minutes, after the sintering, it is free to cool down to obtain a polymer. Teflon friction material.

Example 3

Weigh 70 g of polytetrafluoroethylene, 5 g of nano-boron nitride, 15 g of molybdenum disulfide, 5 g of nano-zirconia, 2 g of carbon quantum dots, and 3 g of lamellar nano-Ti ₃ C ₂ , mix them well in absolute ethanol, and mix them after drying. Put the good powder into the mold, press it for 4 minutes under the pressure of 95MPa, put it into the sintering furnace for sintering after demoulding, gradually heat up from room temperature to 370 ° C, and keep it at 370 ° C for 120 minutes, after the sintering, it is free to cool down to obtain a polymer. Teflon friction material.

Example 4

Weigh 66g of polytetrafluoroethylene, 5g of nano-boron nitride, 15g of molybdenum disulfide, 5g of nano-zirconia, 5g of carbon quantum dots, and 4g of lamellar nano-Ti ₃ C ₂ , mix them well in absolute ethanol, and mix them after drying. Put the good powder into the mold, press it for 3 minutes under the pressure of 80MPa, put it into the sintering furnace for sintering after demoulding, gradually heat up from room temperature to 365 ℃, and keep it at 365 ℃ for 100 minutes, after the sintering, it is free to cool down to obtain the polymer powder. Teflon friction material.

Example 5

Weigh 70g of polytetrafluoroethylene, 4g of nano-boron nitride, 15g of molybdenum disulfide, 1g of nano-zirconia, 5g of carbon quantum dots, and 5g of lamellar nano-Ti ₃ C ₂ , mix them well in absolute ethanol, and mix them after drying. Put the good powder into the mold, press it for 5 minutes under the pressure of 75MPa, put it into the sintering furnace for sintering after demolding, gradually heat up from room temperature to 375 ° C, and keep it at 375 ° C for 110 minutes, after the sintering is completed, it is free to cool down to obtain the polymer powder. Teflon friction material.

Comparative Example 1

Weigh 73 g of polytetrafluoroethylene, 5 g of nano-boron nitride, 15 g of molybdenum disulfide, 5 g of nano-zirconia, and 2 g of carbon quantum dots, mix them evenly in absolute ethanol, and put the mixed powder into the mold after drying. Under the pressure of 95MPa, press for 4 minutes, put it into a sintering furnace for sintering after demoulding, gradually heat up from room temperature to 370 ° C, and keep it at 370 ° C for 120 minutes, and freely cool down after sintering to obtain PTFE friction material.

The PTFE friction materials prepared in Examples 1 to 5 and Comparative Example 1 were tested for start-stop performance. The test conditions were as follows: the ultrasonic motor used was a large ultrasonic motor (diameter of 150 mm), and the PTFE friction material and phosphor bronze were used. For grinding, the running-in time is 40h, and the speed is 120r/min. After running-in, the motor stops for 2 hours, then restarts the motor and measures the static friction torque at this time and the dynamic friction torque after exercise. The friction torque is the average value of 3 to 5 tests. The specific test results are shown in Table 1.

Table 1 Influence of friction materials prepared in Examples and Comparative Examples on the start-stop characteristics of ultrasonic motors

The closer the static and dynamic friction torque is, the better the start-stop characteristics of the ultrasonic motor. Through the examples and comparative examples, it can be found that the lamellar nano-Ti ₃ C ₂ can significantly improve the start-stop characteristics of the ultrasonic motor. In addition, it can also be found from the examples that the more nano-Ti ₃ C ₂ in the lamellae is not the better, the higher the content, the agglomeration will affect the performance, and the improvement effect is not obvious when the content is less.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (8)

1. a polytetrafluoroethylene friction material, is characterized in that, comprises the preparation raw material of following mass parts: 65～80 parts of polytetrafluoroethylene, 1～5 part of nano boron nitride, 5～15 parts of molybdenum disulfide, nanometer 1-5 parts of zirconia, 1-5 parts of carbon quantum dots, and 1-5 parts of lamellar nano-Ti ₃ C ₂ ; the single-layer thickness of the lamellar nano-Ti ₃ C ₂ is 80-100 nm; the polytetrafluoroethylene The particle size of ethylene is 65-75 μm; the sheet diameter of the nano-boron nitride is 0.3-2 nm; the sheet diameter of the molybdenum disulfide is 15-25 μm; the particle size of the nano-zirconia is 20-40 nm; The particle size of the carbon quantum dots is 3-5 nm. 2. The PTFE friction material according to claim 1, wherein the preparation raw materials comprise 70-80 parts of polytetrafluoroethylene, 2-5 parts of nano-boron nitride, 7-15 parts of molybdenum disulfide, nano- 3 to 5 parts of zirconia, 2 to 5 parts of carbon quantum dots, and 2 to 4 parts of lamellar nano-Ti ₃ C ₂ . 3. the preparation method of the described polytetrafluoroethylene friction material of claim 1 or 2, is characterized in that, comprises the following steps: The preparation raw materials are mixed, and the obtained mixed materials are sequentially pressed and sintered to obtain a polytetrafluoroethylene friction material. 4 . The preparation method according to claim 3 , wherein the pressing pressure is 70-100 MPa, and the time is 3-5 min. 5 . 5 . The preparation method according to claim 3 , wherein the sintering temperature is 365-375° C., and the holding time is 90-150 min. 6 . 6 . The preparation method according to claim 3 , wherein the mixing process is as follows: dispersing each preparation raw material into ethanol or acetone, and drying to obtain a mixture. 7 . 7. The application of the polytetrafluoroethylene friction material of claim 1 or 2 or the polytetrafluoroethylene friction material prepared by the preparation method of any one of claims 3 to 6 in an ultrasonic motor. 8 . The application according to claim 7 , wherein the diameter of the ultrasonic motor is more than 150 mm. 9 .

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