High-temperature-resistant and wear-resistant sealing ring and preparation method thereof

Abstract

The invention relates to the technical field of sealing rings, and particularly discloses a high-temperature-resistant and wear-resistant sealing ring and a preparation method thereof. The invention discloses a high-temperature-resistant and wear-resistant sealing ring which is prepared from the following raw materials in parts by weight: 60-70 parts of fluorocarbon elastomer; 1.8 to 2.2 parts of polytetrafluoroethylene; 3-4 parts of a pigment; 20 to 25 parts of filler; 2-2.5 parts of a processing aid; 5.5 to 6 parts of an accelerant; 2 to 5 parts of nano clay; 4 to 6 parts of modified halloysite nanotubes; the modified halloysite nanotube is prepared by the following method: taking a halloysite nanotube raw material and bis-[gamma-(triethoxysilyl) propyl]-tetrasulfide in methylbenzene, stirring and reacting at 100-110 DEG C for 8-10 hours, and then washing, filtering and vacuum drying to obtain the modified halloysite nanotube. In the application process of the sealing ring in the high-temperature and high-pressure environment, large permanent compression deformation is not prone to being generated, and the excellent and stable wear-resistant performance can be achieved by the sealing ring.

Description

Technical Field

[0001] The present application relates to the technical field of sealing rings, and more specifically, to a sealing ring that is resistant to high temperatures and wear and a method for preparing the same. Background Art

[0002] A sealing ring is a device used to prevent leakage of liquid or gas. It is usually made of elastic material and has a sealing function. There are many types of sealing rings in the industry, the most common of which include dust rings, piston rod sealing rings, buffer sealing rings, guide support rings, end cover sealing rings and piston sealing rings. According to the material, they are divided into NBR nitrile rubber sealing rings, HNBR hydrogenated nitrile rubber sealing rings, SIL silicone rubber sealing rings and VITON fluororubber sealing rings.

[0003] Among them, the most prominent feature of VITON fluororubber sealing ring is its excellent high temperature resistance, which can withstand temperatures as high as 300℃ and can work for a long time under working conditions of 200-260℃. It also has excellent chemical stability, and is more stable than other rubbers to organic liquids such as fuel, hydraulic oil, lubricating oil, various dilute and concentrated nitric acid, sulfuric acid, and hydrochloric acid as well as strong oxidants such as high concentration hydrogen peroxide. In addition, its aging resistance, ozone resistance, and mechanical properties are also relatively outstanding. Therefore, it is used as a sealing material and is widely used in national defense, military industry, aerospace, aviation, automobiles, petroleum, and household appliances.

[0004] With regard to the above-mentioned related technologies, the inventors believe that VITON fluororubber sealing rings are often used in high temperature and high pressure environments due to their own particularity. Under high temperature and high pressure environments, the molecular structure of the sealing roll material is easily destroyed, which will lead to permanent compression deformation. As the cross-section becomes more severe, the wear resistance of the sealing ring itself will decrease, and the overall service life will be shortened accordingly.

[0005] Therefore, it is urgent to propose a solution to solve the above technical problems. Summary of the invention

[0006] In order to enable the sealing ring to maintain relatively excellent and stable wear resistance under high temperature and high pressure environment, the present application provides a high temperature resistant and wear resistant sealing ring and a preparation method thereof.

[0007] In a first aspect, the present application provides a high temperature resistant and wear resistant sealing ring, which adopts the following technical solution: A high temperature resistant and wear resistant sealing ring is made of the following raw materials in parts by weight: Fluorocarbon elastomer 60-70 parts; Polytetrafluoroethylene 1.8-2.2 parts; 3-4 parts of pigment; 20-25 parts of filler; 2-2.5 parts of processing aid; Accelerator 5.5-6 parts; 2-5 parts of nano clay; 4-6 parts of modified halloysite nanotubes; The modified halloysite nanotubes are prepared by the following method: The raw material of halloysite nanotubes and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide are separated in toluene, stirred and reacted at 100-110° C. for 8-10 hours, and then washed, filtered and vacuum dried to obtain modified halloysite nanotubes.

[0008] By adopting the above technical scheme, fluorocarbon elastomer is a copolymer composed of carbon fluorine chains, which has excellent chemical resistance, high temperature resistance and low friction coefficient. Polytetrafluoroethylene has excellent high temperature and low temperature resistance, and also has extremely high chemical stability. In addition, PTFE has an extremely low friction coefficient, excellent lubrication performance, and does not adhere to any substance. Fluorocarbon elastomer and polytetrafluoroethylene are used as the main high temperature and wear resistant matrix, and a sealing ring with excellent initial high temperature and wear resistance can be obtained. The use of nanoclay in the sealing ring can hinder the generation and expansion of cracks by utilizing the unique lamellar structure of clay, and then under high temperature and high pressure, it can bring better resistance to the generation of compression permanent deformation, which is conducive to ensuring the stable performance of the wear resistance of the sealing ring. Halloysite nanotubes can enhance mechanical properties, improve thermal stability, flame retardancy and improve other properties. By modifying the raw material of halloysite nanotubes, the modified halloysite nanotubes obtained can show strong interface bonding stability with the polymer, which is more suitable for the application requirements of sealing rings under high temperature and high pressure. At the same time, after the modified halloysite nanotubes and nanoclay are mixed and used, they can play an excellent matching role with each other. Through the mutual attraction and combination between the modified halloysite nanotubes and the nanoclay molecules, and utilizing the hollow nanotube structure of the modified halloysite nanotubes themselves, a better network structure resistant to high temperature and high pressure can be formed in the sealing ring, thereby protecting the sealing ring from large permanent compression deformation during the application process, and can exert excellent and stable wear resistance.

[0009] Preferably, the particle size of the nanoclay is 5-15 μm; the inner diameter of the halloysite nanotube raw material is 50-100 nm, the outer diameter is 120-180 nm, and the tube length is 10-30 μm.

[0010] By adopting the above technical solution, the above-mentioned halloysite nanotube raw materials can be evenly dispersed with the above-mentioned nanoclay during the mixing process after modification, and can play an excellent compounding and synergistic role with each other, so that the sealing ring can exert relatively excellent and stable wear resistance in high temperature and high pressure application environments.

[0011] Preferably, the weight ratio of the modified halloysite nanotubes to the nanoclay is 5:3.

[0012] By adopting the above technical solution, when the modified halloysite nanotubes and nanoclay in the above weight ratio are used in combination, they can form a relatively uniform and tight combination with each other, and can exert an excellent synergistic effect during the application process, so that the sealing ring can show better resistance to permanent compression deformation in high temperature and high pressure application environments, and thus can maintain relatively excellent and stable wear resistance.

[0013] Preferably, the weight ratio of the halloysite nanotube raw material to bis-[γ-(triethoxysilyl)propyl]-tetrasulfide is 100:(2-5).

[0014] By adopting the above technical scheme, in the preparation of modified halloysite nanotubes, the proportions of the above components are matched so that the obtained modified halloysite nanotubes can show excellent dispersibility during the application process and form a relatively tight and stable bond with the polymer matrix. At the same time, the coordination effect between the modified halloysite nanotubes and nanoclay can be better exerted, thereby obtaining a sealing ring that is stable in application in a high temperature and high pressure environment and shows excellent wear resistance.

[0015] Preferably, 1-3 parts by weight of a rare earth composite additive are added to the raw materials of the high temperature resistant and wear resistant sealing ring, and the rare earth composite additive is composed of cerium oxide, lanthanum oxide and yttrium oxide, and the weight ratio of cerium oxide, lanthanum oxide and yttrium oxide is (1.8-2.5):1:(0.4-0.8).

[0016] By adopting the above technical solution, the rare earth composite additive can bring auxiliary reinforcement to the coordination system between modified halloysite nanotubes and nanoclay, and bring significant inhibition to the thermal oxidation degradation of the polymer main chain, which can significantly improve the application stability of the sealing ring in high temperature and high pressure environment. Among them, cerium oxide can induce the resin molecules to form a network structure in a high temperature and high pressure environment; lanthanum oxide can significantly improve the tribological properties of the material, increase the thermal oxidation decomposition temperature of the polymer, and inhibit the thermal oxidation decomposition; yttrium oxide is not easy to deform or damage under high temperature and high pressure conditions; and the three are used as rare earth composite additives, which can not only complement each other, but also act more fully and fully on the coordination system between modified halloysite nanotubes and nanoclay, thereby significantly improving the wear resistance and stability of the sealing ring in a high temperature and high pressure environment.

[0017] Preferably, the weight ratio of the cerium oxide, lanthanum oxide and cerium oxide is 2:1:0.5.

[0018] By adopting the above technical solution, when cerium oxide, lanthanum oxide and cerium oxide in the above weight ratio are used as rare earth composite additives, the corresponding effects are relatively excellent, and the wear resistance and stability of the sealing ring in high temperature and high pressure environment are also significantly improved.

[0019] Preferably, the filler is one or a combination of wollastonite, activated clay, calcium carbonate, alumina, carbon black and talc.

[0020] By adopting the above technical solution, the filler can increase the elasticity and wear resistance of the sealing ring, thereby improving its sealing effect. The above types of fillers can be selected and used according to different working environments of the sealing ring, and can all obtain fillers with good elasticity and sealing performance.

[0021] Preferably, the processing aid is carnauba wax.

[0022] By adopting the above technical solution, carnauba wax is a natural plasticizer with good plasticizing effect and heat resistance. In the sealing ring, carnauba wax can increase the flexibility, ductility and plasticity of rubber, thereby improving the sealing effect and service life of the sealing ring.

[0023] Preferably, the accelerator is calcium hydroxide.

[0024] By adopting the above technical solution, calcium hydroxide can significantly improve the mechanical properties of the sealing ring, such as tensile strength and tear strength, while reducing production costs, and can reduce the acidity of fluororubber and enhance its durability; at the same time, calcium hydroxide can also promote the vulcanization reaction of rubber, increase the crosslinking density and heat resistance of rubber, thereby improving the physical and mechanical properties of rubber.

[0025] In a second aspect, the present application provides a method for preparing a high temperature resistant and wear resistant sealing ring, which adopts the following technical solution: A method for preparing a high temperature resistant and wear resistant sealing ring comprises the following steps: (1) preparing raw materials including fluorocarbon elastomer, polytetrafluoroethylene, pigment, filler, processing aid, accelerator, nanoclay and modified halloysite nanotube according to a ratio; (2) adding fluorocarbon elastomer and polytetrafluoroethylene into a rubber mixer for mixing, and then adding pigment, filler, processing aid, accelerator, nanoclay and modified halloysite nanotubes for further mixing to obtain a premix; (3) The premix is ​​added into a mold of a vulcanizing device for vulcanization, and after vulcanization and shaping, a high temperature resistant and wear resistant sealing ring is obtained.

[0026] By adopting the above technical scheme, the above preparation method is simple to operate and has high production efficiency. During the process, the raw materials can be fully mixed and evenly dispersed, and they can cooperate with each other to exert excellent effects, thereby obtaining a sealing ring that is relatively stable in use under high temperature and high pressure environments, which is suitable for large-scale industrial production.

[0027] In summary, this application has the following beneficial effects: 1. The present invention modifies halloysite nanotubes, and applies the modified halloysite nanotubes and nanoclay in combination in the sealing ring. Through the compound synergistic effect brought by the two, a better network structure resistant to high temperature and high pressure can be formed in the sealing ring, thereby protecting the sealing ring from large compression permanent deformation during the application process, and the sealing ring itself can exert excellent and stable wear resistance; 2. The present application uses a rare earth composite additive composed of cerium oxide, lanthanum oxide and yttrium oxide in the sealing ring, which can not only give full play to its own raw material characteristics, but also assist in the coordination system between the modified halloysite nanotubes and nanoclay, thereby significantly improving the wear resistance and stability of the sealing ring in high temperature and high pressure environments. DETAILED DESCRIPTION

[0028] The present application is further described in detail below in combination with preparation examples, embodiments and comparative examples.

[0029] Unless otherwise specified, the raw materials used in the preparation examples, embodiments and comparative examples of the present application are commercially available: Fluorocarbon elastomer was purchased from Hubei Dali Chemical Co., Ltd. as poly(vinylidene fluoride-co-hexafluoropropylene); The pigment is phthalocyanine green; Nanoclay was purchased from Guangzhou Yifeng Chemical Technology Co., Ltd. Calcined clay; Halloysite nanotube raw materials were purchased from Suzhou Kaifa New Material Technology Co., Ltd.

[0030] Preparation examples of raw materials and / or intermediates Preparation Example 1 A modified halloysite nanotube is prepared by the following method: The raw material of halloysite nanotubes and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide were separated into 5 volumes of toluene, stirred and reacted at 105° C. for 9 h, and then washed, filtered and vacuum dried at 60° C. for 20 h to obtain modified halloysite nanotubes.

[0031] Note: In the above operation, the weight ratio of the halloysite nanotube raw material to bis-[γ-(triethoxysilyl)propyl]-tetrasulfide is 100:3.5; the inner diameter of the halloysite nanotube raw material is 75 nm, the outer diameter is 150 nm, and the tube length is 20 μm.

[0032] Preparation Example 2 A modified halloysite nanotube, which is different from Preparation Example 1 in that it is prepared by the following method: The raw material of halloysite nanotubes and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide were separated into 5 volumes of toluene, stirred and reacted at 100° C. for 10 h, and then washed, filtered and vacuum dried at 60° C. for 20 h to obtain modified halloysite nanotubes.

[0033] Preparation Example 3 A modified halloysite nanotube, which is different from Preparation Example 1 in that it is prepared by the following method: The raw material of halloysite nanotubes and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide were separated into 5 volumes of toluene, stirred and reacted at 110° C. for 8 h, and then washed, filtered and vacuum dried at 60° C. for 20 h to obtain modified halloysite nanotubes.

[0034] Preparation Example 4 A modified halloysite nanotube is different from Preparation Example 1 in that the weight ratio of the halloysite nanotube raw material to bis-[γ-(triethoxysilyl)propyl]-tetrasulfide is 100:2.

[0035] Preparation Example 5 A modified halloysite nanotube is different from Preparation Example 1 in that the weight ratio of the halloysite nanotube raw material to bis-[γ-(triethoxysilyl)propyl]-tetrasulfide is 100:5.

[0036] Preparation Example 6 A modified halloysite nanotube is different from the one prepared in Preparation Example 1 in that the inner diameter of the halloysite nanotube raw material is 50 nm, the outer diameter is 120 nm, and the tube length is 10 μm.

[0037] Preparation Example 7 A modified halloysite nanotube is different from the one prepared in Preparation Example 1 in that the inner diameter of the halloysite nanotube raw material is 100 nm, the outer diameter is 180 nm, and the tube length is 30 μm. Example

[0038] Example 1 A high temperature resistant and wear resistant sealing ring, the raw materials used for its preparation and their corresponding weights are shown in Table 1, and it is prepared by the following steps: (1) preparing raw materials including fluorocarbon elastomer, polytetrafluoroethylene, pigment, filler, processing aid, accelerator, nanoclay and modified halloysite nanotube according to a ratio; (2) adding fluorocarbon elastomer and polytetrafluoroethylene into a rubber mixer and mixing them at 135° C. for 15 minutes, then adding pigment, filler, processing aid, accelerator, nanoclay and modified halloysite nanotubes and mixing them for 20 minutes to obtain a premix; (3) The premix is ​​added into a mold of a vulcanizing device for vulcanization at a vulcanization temperature of 195° C., a vulcanization time of 15 min, and a vulcanization pressure of 15 MPa. After vulcanization and shaping, a high temperature resistant and wear resistant sealing ring is obtained.

[0039] Note: In the above operation, the filler is wollastonite; the processing aid is carnauba wax; the accelerator is calcium hydroxide; the particle size of the nanoclay is 10 μm; and the modified halloysite nanotubes are obtained from Preparation Example 1.

[0040] Example 2-3 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the raw materials used in its preparation and their corresponding weights are shown in Table 1.

[0041] Table 1 Raw materials used in Examples 1-3 and their weight portions (kg / portion) raw material Example 1 Example 2 Example 3 Fluorocarbon elastomer 65 60 70 Polytetrafluoroethylene 2 1.8 2.2 pigment 3.5 3 4 filler 22.5 20 25 Processing Aids 2.25 2 2.5 Accelerator 2.75 5.5 6 Nano Clay 3.5 2 5 Modified Halloysite Nanotubes 5 4 6 Example 4 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the particle size of the nano clay is 5 μm.

[0042] Example 5 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the particle size of the nano clay is 15 μm.

[0043] Example 6 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the modified halloysite nanotubes are obtained from Preparation Example 2.

[0044] Example 7 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the modified halloysite nanotubes are obtained from Preparation Example 3.

[0045] Example 8 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the modified halloysite nanotubes are obtained from Preparation Example 4.

[0046] Example 9 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the modified halloysite nanotubes are obtained from Preparation Example 5.

[0047] Example 10 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the modified halloysite nanotubes are obtained from Preparation Example 6.

[0048] Embodiment 11 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the modified halloysite nanotubes are obtained from Preparation Example 7.

[0049] Example 12 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that 2 parts by weight of a rare earth composite additive are also added to the raw material, the rare earth composite additive is composed of cerium oxide, lanthanum oxide and yttrium oxide in a weight ratio of 2:1:0.5, and the rare earth composite additive is added together with modified halloysite nanotubes and nanoclay when used, and the particle size is 70nm.

[0050] Example 13 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that the weight portion of rare earth composite additive added is 1 part.

[0051] Embodiment 14 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that the weight portion of rare earth composite additive added is 3 parts.

[0052] Embodiment 15 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that the rare earth composite additive is composed of cerium oxide, lanthanum oxide and yttrium oxide in a weight ratio of 2.15:1:0.6.

[0053] Example 16 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that the rare earth composite additive is composed of cerium oxide, lanthanum oxide and yttrium oxide in a weight ratio of 1.8:1:0.4.

[0054] Embodiment 17 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that the rare earth composite additive is composed of cerium oxide, lanthanum oxide and yttrium oxide in a weight ratio of 2.5:1:0.8.

[0055] Embodiment 18 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that cerium oxide is not used in the raw materials.

[0056] Embodiment 19 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that lanthanum oxide is not used in the raw materials.

[0057] Embodiment 20 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that yttrium oxide is not used in the raw materials.

[0058] Embodiment 21 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that cerium oxide and lanthanum oxide are not used in the raw materials.

[0059] Embodiment 22 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that cerium oxide and yttrium oxide are not used in the raw materials.

[0060] Embodiment 23 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that lanthanum oxide and yttrium oxide are not used in the raw materials.

[0061] Embodiment 24 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that the total amount of modified halloysite nanotubes and nanoclay remains unchanged, and the weight ratio of the two is adjusted to 5:3.

[0062] Comparative Example Comparative Example 1 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that modified halloysite nanotubes are not used in the raw materials.

[0063] Comparative Example 2 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that nano clay is not used in the raw materials.

[0064] Comparative Example 3 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that modified halloysite nanotubes and nanoclay are not used in the raw materials.

[0065] Comparative Example 4 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that the mass of modified halloysite nanotubes is replaced by halloysite nanotube raw materials.

[0066] Comparative Example 5 A high temperature resistant and wear resistant sealing ring, which is different from Example 1 in that nano clay is not used in the raw material, and the quality of modified halloysite nanotubes is replaced by halloysite nanotube raw materials.

[0067] Comparative Example 6 A high temperature resistant and wear resistant sealing ring, which is different from Example 12 in that modified halloysite nanotubes and nanoclay are not used in the raw materials.

[0068] Performance test samples: The high temperature and wear resistant sealing rings obtained in Examples 1-24 are used as test samples 1-24, and the high temperature and wear resistant sealing rings obtained in Comparative Examples 1-6 are used as control samples 1-6; both the test samples and the control samples are O-type sealing rings with a specification of DN65mm×40mm×4mm.

[0069] Test method: Take a high temperature and wear resistant sealing ring, weigh it to measure the initial weight, and wear it with a TX020 NBS rubber wear tester. After 5 minutes, weigh the final mass of each standard sample, and the difference between the initial mass and the final mass is the wear value A. Then, the high temperature and wear resistant sealing ring is placed in a high temperature and high pressure environment for 192 hours, with a temperature of 232°C and a pressure of 5MPa; then, it is taken out and naturally cooled for 12 hours, and the wear value is measured in the same way as above, and recorded as the wear value B; Finally, the wear value growth rate is calculated, wear value growth rate = (BA) / A. The greater the wear value growth rate, the better the wear resistance stability of the sealing ring under high temperature and high pressure.

[0070] After completing the test samples 1-24 and the control samples 1-6 according to the above method, the test results are recorded in Table 2 accordingly.

[0071] Table 2 Test results of test samples 1-24 and control samples 1-6 From Examples 1-3 and Comparative Examples 1-3 and Table 2, it can be seen that the modified halloysite nanotubes and nanoclay are used in combination in the sealing ring. The synergistic effect of the combination brought by the two can significantly improve the wear resistance stability of the sealing ring under high temperature and high pressure, and the wear value growth rate obtained by the test is significantly lower; and if any one of the modified halloysite nanotubes and nanoclay is used alone in the sealing ring, although the wear value growth rate can be reduced, the effect brought is limited, and the sum of the improvement effects brought by the use of the modified halloysite nanotubes and nanoclay alone is far less than the improvement effect brought by the combination of the two. It can be seen that the combination of modified halloysite nanotubes and nanoclay can bring a significant improvement effect of 1+1>2. Combined with Comparative Examples 4-5 and Table 2, it can be seen that if the mass of modified halloysite nanotubes is replaced with halloysite nanotube raw materials, it can be clearly seen that the improvement effect brought by the application of halloysite nanotube raw materials is far less than that of modified halloysite nanotubes, and the combination of halloysite nanotube raw materials and nanoclay can only bring a simple superposition of the improvement effect, but cannot play an excellent compound synergistic effect. In summary, it can be seen that the combination of modified halloysite nanotubes and nanoclay can play a more significant effect, so that the wear resistance and stability of the sealing ring under high temperature and high pressure are significantly improved.

[0072] It can be seen from Example 1 and Examples 4-9 in combination with Table 2 that in the preparation of modified halloysite nanotubes, the inner diameter of the halloysite nanotube raw material is controlled to be 50-100nm, the outer diameter is 120-180nm, and the tube length is 10-30μm, and the modified halloysite nanotubes finally obtained can all play an excellent and stable role. At the same time, the particle size of the nanoclay is 5-15μm, and it can also play an excellent and stable cooperation role with the modified halloysite nanotubes. It can be seen from Example 24 in combination with Table 2 that when the weight ratio of the modified halloysite nanotubes and the nanoclay is 5:3, the cooperation effect of the two is better, so that the sealing ring can maintain a relatively excellent and stable wear resistance in the application environment of high temperature and high pressure.

[0073] It can be seen from Example 1 and Example 12-17 and Table 2 that the present application uses a rare earth composite additive composed of cerium oxide, lanthanum oxide and yttrium oxide in the sealing ring, which can further reduce the wear value growth rate, indicating that the wear resistance stability of the sealing ring in a high temperature and high pressure environment is significantly improved. It can be seen from Example 18-23 and Table 2 that the addition and use of any one or two of cerium oxide, lanthanum oxide and yttrium oxide not only has a limited improvement effect, but also can only bring a simple effect superposition to each other, and only when the three are used together, can they play an excellent composite synergistic effect. It can be seen from Comparative Examples 3 and 6 and Table 2 that the rare earth composite additive can assist in the coordination system between the modified halloysite nanotubes and nanoclays, thereby bringing about the excellent effect of the performance. In the absence of modified halloysite nanotubes and nanoclays, the effect of the rare earth composite additive will be significantly reduced.

[0074] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high temperature and wear resistant sealing ring, characterized in that: Made from the following raw materials in parts by weight: Fluorocarbon elastomer 60-70 parts; Polytetrafluoroethylene 1.8-2.2 parts; 3-4 parts of pigment; 20-25 parts of filler; 2-2.5 parts of processing aid; Accelerator 5.5-6 parts; 2-5 parts of nano clay; 4-6 parts of modified halloysite nanotubes; The modified halloysite nanotubes are prepared by the following method: The raw material of halloysite nanotubes and bis-[γ-(triethoxysilyl)propyl]-tetrasulfide are separated in toluene, stirred and reacted at 100-110° C. for 8-10 hours, and then washed, filtered and vacuum dried to obtain modified halloysite nanotubes.

2. The high temperature and wear resistant sealing ring according to claim 1, characterized in that: The particle size of the nano clay is 5-15 μm; the inner diameter of the halloysite nanotube raw material is 50-100 nm, the outer diameter is 120-180 nm, and the tube length is 10-30 μm.

3. The high temperature and wear resistant sealing ring according to claim 1, characterized in that: The weight ratio of the modified halloysite nanotubes to the nanoclay is 5:

3.

4. The high temperature and wear resistant sealing ring according to claim 1, characterized in that: The weight ratio of the halloysite nanotube raw material to bis-[γ-(triethoxysilyl)propyl]-tetrasulfide is 100:(2-5).

5. The high temperature and wear resistant sealing ring according to claim 1, characterized in that: The raw materials of the high-temperature-resistant and wear-resistant sealing ring are also added with 1-3 parts by weight of a rare earth composite additive, wherein the rare earth composite additive is composed of cerium oxide, lanthanum oxide and yttrium oxide, and the weight ratio of cerium oxide, lanthanum oxide and yttrium oxide is (1.8-2.5):1:(0.4-0.8).

6. The high temperature and wear resistant sealing ring according to claim 5, characterized in that: The weight ratio of the cerium oxide, lanthanum oxide and cerium oxide is 2:1:0.

5.

7. The high temperature and wear resistant sealing ring according to claim 1, characterized in that: The filler is one or a combination of wollastonite, activated clay, calcium carbonate, alumina, carbon black and talcum powder.

8. The high temperature and wear resistant sealing ring according to claim 1, characterized in that: The processing aid is carnauba wax.

9. The high temperature and wear resistant sealing ring according to claim 1, characterized in that: The accelerator is calcium hydroxide.

10. The method for preparing the high temperature resistant and wear resistant sealing ring according to claim 1, characterized in that: The following steps are involved: (1) preparing raw materials including fluorocarbon elastomer, polytetrafluoroethylene, pigment, filler, processing aid, accelerator, nanoclay and modified halloysite nanotube according to a proportion; (2) adding fluorocarbon elastomer and polytetrafluoroethylene into a rubber mixer for mixing, and then adding pigment, filler, processing aid, accelerator, nanoclay and modified halloysite nanotube for further mixing to obtain a premix; (3) The premix is ​​added into a mold of a vulcanizing device for vulcanization. After vulcanization and shaping, a high temperature resistant and wear resistant sealing ring is obtained.

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