Lubricating material with high surface and low friction coefficient under multiple friction and preparation method
By adding PTFE micro powder, fibers, and high-temperature resistant lubricants to the UHMWPE slider to form a lubricating film, the problem of unstable friction coefficient of the UHMWPE slider under high surface pressure is solved, the anti-creep performance and heat resistance are improved, and low-friction and long-life sliding performance is achieved.
Patent Information
- Application Number
- CN202511991885.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-02-27
AI Technical Summary
Existing UHMWPE sliders have unstable friction coefficients, insufficient creep resistance, and poor heat resistance under high surface pressure and long-term heavy loads, and cannot meet the requirements of sliding conditions with extreme high surface pressure, low friction, and long service life.
By adding PTFE micro powder, PTFE fiber, high-temperature lubricant and reinforcement such as glass fiber and carbon fiber to UHMWPE, and then mixing them after surface pretreatment, a lubricating film is formed, which reduces the coefficient of friction and improves the creep resistance.
The coefficient of friction remains below 0.04 under high surface pressure and remains stable after repeated friction, with improved heat resistance, meeting the requirements for use in high-temperature environments.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of sliders for seismic isolation bearings, specifically relating to a lubricating material with high surface pressure and low friction coefficient under multiple friction conditions and its preparation method. Background Technology
[0002] With increasingly stringent requirements for vibration isolation and damping technology, the need to improve the performance of sliding block materials used in seismic isolation bearings is becoming increasingly urgent. While traditional PTFE sliding blocks for seismic isolation bearings possess extremely low friction coefficients, their poor creep resistance and mechanical strength limit their reliable application under higher surface pressures and long-term heavy loads. Ultra-high molecular weight polyethylene (UHMWPE), with a similarly low friction coefficient, exhibits unique advantages under high surface pressure loads due to its excellent wear resistance and high strength. However, UHMWPE's friction coefficient is not consistently stable; the friction coefficient in the second friction test is significantly higher than the first. Existing UHMWPE modification technologies offer limited improvement in lubrication, and repeated friction tests with the same set of sliding blocks result in significant lubrication failure. Furthermore, its heat resistance is low, with mechanical properties significantly decreasing above 110°C. Molybdenum disulfide and other materials offer only weak lubrication effects for current UHMWPE materials. Therefore, further optimization of its friction coefficient and creep resistance is needed to meet the requirements of extremely high surface pressures, low friction, and long service life in sliding conditions. Summary of the Invention
[0003] Based on the shortcomings of the existing technology, the present invention provides a lubricating material with high surface pressure and low friction coefficient under multiple friction conditions and a preparation method thereof, which reduces the friction coefficient of ultra-high molecular weight polyethylene and improves its anti-creep performance, so as to meet the requirements of sliding conditions with extreme high surface pressure, low friction and long service life.
[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problem is as follows: The present invention discloses a lubricating material with high surface pressure and low friction coefficient under multiple friction conditions, wherein the raw materials are formulated in the following proportions: 100 parts of matrix material, 5-30 parts of lubricating carrier, 0.5-20 parts of lubricant, 1-5 parts of reinforcing body and 0.05-0.5 parts of coupling agent.
[0005] Preferably, the matrix material is UHMWPE, with a molecular weight of 5-8 million and a particle size of 200-300 μm.
[0006] Preferably, the lubricating carrier is one or both of PTFE micro powder and PTFE fiber, wherein the particle size of the PTFE micro powder is 2-80 μm.
[0007] Preferably, the lubricant is one or both of high-temperature resistant lubricant particles or graphene sheets, wherein the lubricant particle size is maintained at 50-1000 μm, and the graphene sheets have a multilayer structure of 3-5 layers.
[0008] Preferably, the reinforcement is one or more of glass fiber, carbon fiber, silicon carbide, boron nitride, poly(p-phenylene benzodioxazole) fiber, or nano zinc oxide, wherein the glass fiber has a particle size of 200-400 μm, the carbon fiber has a particle size of 100-2000 μm, the silicon carbide and boron nitride have a particle size of 0.5-5 μm, the poly(p-phenylene benzodioxazole) fiber is a short-cut fiber with a length of 0.01-1 mm, and the nano zinc oxide has a particle size of 5-50 nm.
[0009] Preferably, the coupling agent is coupling agent KH550 or coupling agent KH570.
[0010] Another technical problem to be solved by the present invention is to provide a method for preparing a lubricating material with high surface pressure and low friction coefficient under multiple friction conditions, comprising the following steps: S1. Ingredients: Weigh the matrix material, lubricating carrier, lubricant, reinforcing agent and coupling agent according to the weight of each raw material; S2. Pretreatment: The lubricating carrier and the reinforcement are pretreated to obtain lubricating carrier powder and reinforcement powder, wherein PTFE micro powder, boron nitride and poly(p-phenylenebenzodioxazole) fiber are specially pretreated. S3. Mixing: Place the lubricant and the lubricating carrier powder obtained in S2 into container one and stir at high speed for 30 minutes to obtain mixture one. Divide the matrix material into two equal parts. Place one part of the matrix material and the reinforcing powder obtained in S2 into container two and stir for 30 minutes to obtain mixture two. Add the other part of the matrix material to mixture two to obtain mixture three. Stir mixture three and mixture one at high speed for 2-4 hours to ensure thorough mixing and obtain the mixture. S4. Compression molding: Place the mixture obtained in S3 into a compression molding machine and press at room temperature for 30 minutes to densify the powder, with the pressure set at 10-30 MPa; raise the temperature to 170-230℃ to melt the powder, with a pressure of 3-5 MPa, and hot press for 30 minutes; rapidly cool to below 80℃, with a pressure of 5-20 MPa, and cold press for 120-240 minutes before releasing the pressure and demolding.
[0011] Preferably, in step S2, the pretreatment methods for PTFE micro powder and boron nitride are the same, and the specific steps are as follows: S211. Coupling agent KH550 and coupling agent KH570 are mixed in a ratio of 1:3 to obtain a coupling agent solution. Water and anhydrous ethanol are added to the coupling agent solution to prepare an active dilute solution with a concentration of 0.1-1%. S212. Divide the active dilute solution into two parts, and add the PTFE micro powder to be treated and boron nitride to the active dilute solution respectively to obtain mixture one and mixture two. S213. Mixture 1 and Mixture 2 are magnetically stirred at 60°C for 1-2 hours. S214. Wash the two completely reacted mixtures, one and two, three times each with anhydrous ethanol. S215. Place the cleaned mixture one and mixture two into a low-temperature oven and dry them at 40°C to constant weight. Grind and sieve to obtain PTFE micro powder and boron nitride powder.
[0012] Preferably, in step S02, the pretreatment method for poly(p-phenylenebenzodioxazole) fibers is as follows: S221. Poly(p-phenylenebenzodioxazole) fiber is impregnated in dopamine hydrochloride solution, stirred slowly at room temperature and allowed to stand for 1-2 days to react. The concentration of dopamine hydrochloride solution is 1-2 mg / ml. S222. After the reaction is allowed to stand, the poly(p-phenylene benzodioxazole) fiber is taken out, washed repeatedly with deionized water 3 times, and dried at 60°C to constant weight to obtain dried poly(p-phenylene benzodioxazole) fiber.
[0013] Compared with the prior art, the advantages of the present invention are: This invention discloses a high surface pressure, low friction coefficient lubricating material under multiple friction conditions. By adding reinforcing and lubricating components to ultra-high molecular weight polyethylene, it significantly reduces the friction coefficient while enhancing mechanical properties. By optimizing the friction coefficient and creep resistance of ultra-high molecular weight polyethylene, it can reduce the friction coefficient between a slider and a stainless steel plate under high surface pressure (not less than 90 MPa). After repeated friction, the friction coefficient of the slider remains at a level of less than 0.04. At the same time, it can improve the heat resistance of the slider, maintain a low friction coefficient under high-temperature operating environments, and retain wear and other properties. Detailed Implementation
[0014] The technical solution 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.
[0015] This invention discloses a high surface pressure and low friction coefficient lubricating material under multiple friction conditions, comprising, by the following proportions: 100 parts of matrix material, 5-30 parts of lubricating carrier, 0.5-20 parts of lubricant, 1-5 parts of reinforcement, coupling agent KH550, and coupling agent KH570, wherein: (1) Raw materials The matrix material is UHMWPE, with a molecular weight of 5-8 million and a particle size of 200-300 μm.
[0016] The lubricating carrier is one or both of PTFE micro powder and carbon fiber, wherein the particle size of PTFE micro powder is 2-80μm and the particle size of carbon fiber is 100-2000μm.
[0017] The lubricant is a high-temperature resistant lubricant particle and graphene sheet, and the lubricant particle size is maintained at 50-1000μm.
[0018] The reinforcement is one or more of glass fiber, carbon fiber, silicon carbide, boron carbide, modified poly(p-phenylene benzodioxazole) fiber or nano zinc oxide, wherein the particle size of silicon carbide and boron carbide is 0.5-5 μm, the poly(p-phenylene benzodioxazole) fiber is a short-cut fiber with a length of 0.01-1 mm, and the particle size of nano zinc oxide is 5-50 nm.
[0019] Both PTFE micro powder and PTFE fiber in the lubricating carrier can adsorb some of the lubricant and form a lubricating film on the slider surface under high shear, thereby reducing the coefficient of friction. PTFE micro powder, boron nitride, and poly(p-phenylene benzodioxazole) fiber have poor compatibility with the UHMWPE matrix, so these additives need to be pretreated on the surface.
[0020] The pretreatment methods for PTFE micro powder and boron nitride are the same, and the specific steps are as follows: (1) Coupling agent KH550 and coupling agent KH570 are mixed in a ratio of 1:3 to obtain a coupling agent solution. Water and anhydrous ethanol are added to the coupling agent solution to prepare an active dilute solution with a concentration of 0.1-1%. (2) Divide the active dilute solution into two parts, and add the PTFE micro powder to be treated and boron nitride to the active dilute solution to obtain mixture one and mixture two respectively; (3) Mixture 1 and Mixture 2 are magnetically stirred at 60°C for 1-2 hours; (5) Wash the fully reacted mixture one and mixture two three times with anhydrous ethanol respectively; (5) Place the cleaned mixture one and mixture two into a low temperature oven and dry them at 40°C to constant weight. Grind and sieve to obtain PTFE micro powder and boron nitride powder.
[0021] The pretreatment method for poly(p-phenylenebenzodioxazole) fibers is as follows: (1) The poly(p-phenylenebenzodioxazole) fiber is impregnated in a dopamine hydrochloride solution, stirred slowly at room temperature and allowed to stand for 1-2 days to react. The concentration of the dopamine hydrochloride solution is 1-2 mg / ml. (2) After the reaction is allowed to stand, the poly(p-phenylene benzodioxazole) fiber is taken out, washed repeatedly with deionized water 3 times, and dried at 60°C to constant weight to obtain dried poly(p-phenylene benzodioxazole) fiber.
[0022] Examples and comparative examples are given below: Example 1: Mixture 1 was prepared by premixing 10g of 1μm coupling-treated PTFE micro powder and 6g of high-temperature lubricant for 30min. Mixture 2 was prepared by stirring 100g of UHMWPE and 3g of reinforcing filler carbon fiber for 30min. The remaining 100g of UHMWPE powder and mixture 1 were added to mixture 2 and stirred at high speed for 4h to ensure thorough mixing.
[0023] The mixture is placed in a molding press and pressed at room temperature for 30 minutes to densify the powder at a pressure of 10 MPa; the temperature is raised to 230°C to melt the powder at a pressure of 3 MPa and hot-pressed for 30 minutes; the mixture is then rapidly cooled to a temperature of 80°C or below and a pressure of 15 MPa, cold-pressed for 120 minutes, and then the pressure is released and the mold is demolded.
[0024] Example 2: Mixture 1 was prepared by premixing 10g of PTFE fiber and 6g of 5-layer graphene sheet for 30min. Mixture 2 was prepared by stirring 100g of UHMWPE, 3g of reinforcing carbon fiber and 2g of silicon carbide for 30min. The remaining 100g of UHMWPE powder and mixture 1 were added to mixture 2 and stirred at high speed for 4h to ensure thorough mixing.
[0025] The mixture is placed in a molding press and pressed at room temperature for 30 minutes to densify the powder at a pressure of 10 MPa; the temperature is raised to 230°C to melt the powder at a pressure of 3 MPa and hot-pressed for 30 minutes; the mixture is then rapidly cooled to a temperature of 80°C or below and a pressure of 15 MPa, cold-pressed for 120 minutes, and then the pressure is released and the mold is demolded.
[0026] Example 3: Mixture 1 was prepared by premixing 10g of PTFE fiber and 6g of high-temperature lubricant for 30 minutes. Mixture 2 was prepared by stirring 100g of UHMWPE, 3g of reinforcing carbon fiber, and 2g of silicon carbide for 30 minutes. The remaining 100g of UHMWPE powder and mixture 1 were added to mixture 2 and stirred at high speed for 4 hours to ensure thorough mixing.
[0027] The mixture is placed in a molding press and pressed at room temperature for 30 minutes to densify the powder at a pressure of 10 MPa; the temperature is raised to 230°C to melt the powder at a pressure of 3 MPa and hot-pressed for 30 minutes; the mixture is then rapidly cooled to a temperature of 80°C or below and a pressure of 15 MPa, cold-pressed for 120 minutes, and then the pressure is released and the mold is demolded.
[0028] Comparative Example 1: Place 220g of pure UHMWPE material into a molding press and press at room temperature for 30 minutes to densify the powder at a pressure of 10MPa; raise the temperature to 230℃ to melt the powder at a pressure of 3MPa and hot press for 30 minutes; rapidly cool to a temperature of 80℃ or below at a pressure of 15MPa and cold press for 120 minutes before releasing the pressure and demolding.
[0029] Table 1 lists the test results of the dynamic friction coefficient of the sliders in Examples 1-3 and Comparative Example 1 under different pressures.
[0030] Table 1: Coefficients of dynamic friction of sliders with different formulations under different pressures As shown in Table 1, both PTFE micro powder and PTFE fiber have the function of carrying lubricant, and both high-temperature resistant lubricant and graphene sheet have a certain lubrication effect. The friction coefficient of Example 3 is smaller than that of Example 1, indicating that the carrying effect of PTFE fiber is better than that of PTFE micro powder. The friction coefficient of Example 3 is also smaller than that of Example 2, indicating that the lubrication effect of high-temperature resistant lubricant on UHMWPE matrix is better than that of graphene sheet. Therefore, high-temperature resistant lubricant is preferred to reduce the friction coefficient.
[0031] The dynamic friction coefficient test of the slider in Example 3 was repeated multiple times under different pressures. After each test, the slider and the grinding surface were wiped clean with anhydrous ethanol. The test results are shown in Table 2.
[0032] Table 2: Coefficient of kinetic friction of the slider in Example 3 under different pressures for repeated applications As shown in Table 2, although the coefficient of friction increases slightly with the increase of the number of friction cycles, it remains at a low level. For example, the coefficient of friction is less than 0.04 at 45 MPa and less than 0.03 at 90 MPa. This indicates that the high-temperature resistant lubricant used in Example 3 is a long-lasting lubricant with stable lubrication effect.
[0033] This invention discloses a lubricating material with high surface pressure and low friction coefficient under multiple friction conditions. It uses PTFE micro powder or fiber to adsorb the lubricant. During the friction process, the PTFE falls off along with the lubricant to form a lubricating film on the surface of the slider. Sufficient lubricant and a small amount of reinforcing filler are added to significantly reduce the friction coefficient while ensuring mechanical properties, so as to meet the requirement of low friction coefficient under high surface pressure. The lubricant is long-lasting and resistant to high temperature and high pressure, so that the friction coefficient remains at a low level after multiple frictions and high temperature treatment at 120°C.
[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A high face pressure, low coefficient of friction lubricating material under multiple rubs, characterized by, The raw materials are proportioned by parts, including: 100 parts of base material, 5-30 parts of lubricating carrier, 0.5-20 parts of lubricant, 1-5 parts of reinforcing body and 0.05-0.5 parts of coupling agent.
2. The high face pressure, low friction coefficient lubricating material of claim 1, wherein: The base material is UHMWPE, with a molecular weight of 5-8 million and a particle size of 200-300 μm.
3. The high face pressure, low friction coefficient lubricating material of claim 1, wherein: The lubricating carrier is one or both of PTFE micro powder or PTFE fiber, wherein the particle size of PTFE micro powder is 2-80 μm.
4. The high face pressure, low friction coefficient lubricating material of claim 1, wherein: The lubricant is one or both of high-temperature resistant lubricant particles or graphene sheets, with a particle size of 50-1000 μm, and the graphene sheets are multi-layer structures with 3-5 layers.
5. The high face pressure, low friction coefficient lubricating material of claim 1, wherein: The reinforcing body is one or more of glass fiber, carbon fiber, silicon carbide, boron nitride, poly-p-phenylene benzobisoxazole fiber or nano zinc oxide, wherein the particle size of glass fiber is 200-400 μm, the particle size of carbon fiber is 100-2000 μm, the particle size of silicon carbide and boron nitride is 0.5-5 μm, the poly-p-phenylene benzobisoxazole fiber is a chopped fiber with a length of 0.01-1 mm, and the particle size of nano zinc oxide is 5-50 nm.
6. The high face pressure, low friction coefficient lubricating material of claim 1, wherein: The coupling agent is coupling agent KH550 and coupling agent KH570.
7. A method of producing a high face pressure, low friction coefficient lubricating material according to any one of claims 1 to 6, characterized in that The method comprises the following steps: S1, batching: weighing the base material, lubricating carrier, lubricant, reinforcing body and coupling agent according to the weight of each raw material; S2, pretreatment: pretreating the lubricating carrier and reinforcing body to obtain lubricating carrier powder and reinforcing body powder, wherein PTFE micro powder, boron nitride and poly-p-phenylene benzobisoxazole fiber are subjected to special pretreatment; S3, mixing: putting the lubricant and the lubricating carrier powder obtained in S2 into container one for high-speed stirring for 30 min to prepare mixture one, dividing the base material into two equal parts, putting one part of the base material and the reinforcing body powder obtained in S2 into container two for stirring for 30 min to prepare mixture two, adding the other part of the base material into mixture two to obtain mixture three, and high-speed stirring mixture three and mixture one for 2-4 h to fully mix them to obtain the mixed material; S4, mold pressing: putting the mixed material obtained in S3 into a mold pressing machine for normal temperature pressing for 30 min to densify the powder, wherein the pressure is set to 10-30 MPa; the temperature is raised to 170-230 ℃ to melt the powder, the pressure is 3-5 MPa, and hot pressing is performed for 30 min; fast cooling to a temperature below 80 ℃, pressure of 5-20 MPa, and cold pressing for 120-240 min before unloading and demolding.
8. The method of claim 7, wherein the method further comprises: In the step S2, the pretreatment methods of PTFE micro powder and boron nitride are the same, and the specific steps are as follows: S211, mixing coupling agent KH550 and coupling agent KH570 in a ratio of 1:3 to obtain a coupling agent solution, adding water and anhydrous ethanol into the coupling agent solution to prepare an active dilute solution, and the concentration of the active dilute solution is 0.1-1%; S212, dividing the active dilute solution into two parts, and adding the PTFE micro powder and boron nitride to be treated into the active dilute solution to obtain mixture one and mixture two; S213, magnetic stirring reaction of mixture one and mixture two at 60 ℃ for 1-2 h; S214. Wash the two completely reacted mixtures, one and two, three times each with anhydrous ethanol. S215. Place the cleaned mixture one and mixture two into a low-temperature oven and dry them at 40°C to constant weight. Grind and sieve to obtain PTFE micro powder and boron nitride powder.
9. The method of claim 7, wherein the method further comprises: In step S2, the pretreatment method for poly(p-phenylenebenzodioxazole) fibers is as follows: S221. Poly(p-phenylenebenzodioxazole) fiber is impregnated in dopamine hydrochloride solution, stirred slowly at room temperature and allowed to stand for 1-2 days to react. The concentration of dopamine hydrochloride solution is 1-2 mg / ml. S222. After the reaction is allowed to stand, the poly(p-phenylene benzodioxazole) fiber is taken out, washed repeatedly with deionized water 3 times, and dried at 60°C to constant weight to obtain dried poly(p-phenylene benzodioxazole) fiber.