Corrosion-resistant PEEK sealing material for sealing check ring and preparation method of corrosion-resistant PEEK sealing material

Abstract

The invention relates to the technical field of composite materials, in particular to a corrosion-resistant PEEK sealing material for a sealing check ring and a preparation method of the corrosion-resistant PEEK sealing material. The preparation method specifically comprises the following steps: step 1, initiating polymerization of PEEK resin containing double bonds, PTFE micro powder and sodium allysulfonate by ultraviolet radiation to obtain modified PTFE resin; 2, grafting the oxidized carbon fibers with a silane coupling agent to obtain modified carbon fibers; and 3, adding PEEK resin, modified PTFE resin, modified carbon fibers, a methyl vinyl ether-maleic anhydride copolymer, carbon fibers and a lubricant into a double-screw extruder, uniformly mixing, extruding and granulating to obtain the corrosion-resistant PEEK sealing material for the sealing retainer ring. The PEEK sealing material has the advantages of excellent corrosion resistance, excellent wear resistance and good processability, and can be used for preparing a sealing check ring with better sealing performance.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, in particular to a corrosion-resistant PEEK sealing material for a sealing retaining ring and a preparation method thereof. Background Art

[0002] Sealing rings are usually used in equipment and systems that require sealing and corrosion resistance, such as chemical equipment, marine engineering, aerospace, and medical equipment. Common sealing ring materials include polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), nitrile rubber (NBR), etc. The choice of different materials will directly affect the service life and performance stability of the sealing ring. The most important thing about the sealing ring is the sealing performance, which will be affected by the environment, such as high temperature, high pressure, and highly corrosive environment. Therefore, the sealing ring needs to have excellent tolerance and long-term stability to ensure the reliable operation of the equipment and system.

[0003] Based on this, the present invention will provide a corrosion-resistant PEEK sealing material, and the sealing retaining ring processed by the material has excellent corrosion resistance and wear resistance, and can maintain stability for a long time, and has excellent sealing performance. Summary of the invention

[0004] The object of the present invention is to provide a corrosion-resistant PEEK sealing material for a sealing retaining ring and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A corrosion-resistant PEEK sealing material for a sealing retaining ring comprises the following components: by weight, 50-65 parts of PEEK resin, 10-20 parts of modified PTFE resin, 5-15 parts of modified carbon fiber, 5-10 parts of methyl vinyl ether-maleic anhydride copolymer, 5-10 parts of carbon fiber, and 1-3 parts of lubricant.

[0007] Furthermore, the method for preparing the corrosion-resistant PEEK sealing material for the sealing retaining ring comprises the following steps:

[0008] Step 1: ultraviolet irradiation initiates polymerization of PEEK resin containing double bonds, PTFE powder, and sodium allyl sulfonate to obtain modified PTFE resin;

[0009] Step 2: Grafting the oxidized carbon fiber with a silane coupling agent to obtain a modified carbon fiber;

[0010] Step 3: Add PEEK resin, modified PTFE resin, modified carbon fiber, methyl vinyl ether-maleic anhydride copolymer, carbon fiber, and lubricant into a twin-screw extruder, mix evenly, extrude and granulate, and obtain a corrosion-resistant PEEK sealing material for a sealing retaining ring.

[0011] Furthermore, the preparation method of the modified PTFE resin is as follows: (1) PEEK resin, sodium borohydride and dimethyl sulfoxide are added to a reaction container, stirred and heated to 115-125° C., reacted for 6-12 hours, terminated the reaction, filtered out the solution to obtain a filter cake, and finally washed it with anhydrous ethanol, hydrochloric acid solution and deionized water in sequence, and dried to obtain a hydroxylated PEEK resin; (2) After heating the reaction container containing dimethylformamide to 45-60° C., hydroxylated PEEK resin, 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide are added thereto, and then ultrasonically dispersed for 10-20 minutes, and then acrylic acid is added, stirred in the dark for reaction for 12-24 hours, terminated the reaction, and finally filtered out the solution to obtain a filter cake, and then The PTFE resin is first irradiated and cracked under irradiation conditions of 500 to 3500 kGy, then added to anhydrous ethanol, stirred and heated to 150 to 200° C., and kept warm for 6 to 12 hours. Finally, it is washed with deionized water, dried and ground to obtain PTFE powder. (4) The PEEK resin containing double bonds, PTFE powder, sodium allyl sulfonate and dimethylformamide are added to a reaction container, stirred and heated to 45 to 60° C., and then stirred for 1 to 3 hours. Then, under stirring, 365 nm ultraviolet light is used to initiate polymerization for 30 to 60 minutes, and the reaction is terminated to obtain a modified PTFE resin.

[0012] Furthermore, the preparation of the hydroxylated PEEK resin includes the following components: by weight, 6 to 12 parts of PEEK resin, 1 to 2 parts of sodium borohydride, and 50 parts of dimethyl sulfoxide.

[0013] Furthermore, the preparation of the double bond-containing PEEK resin includes the following components: by weight, 5-10 parts of hydroxylated PEEK resin, 15 parts of acrylic acid, 0.15-0.3 parts of 4-dimethylaminopyridine, 15-20 parts of N,N'-dicyclohexylcarbodiimide, and 100 parts of dimethylformamide.

[0014] Furthermore, the preparation of the modified PTFE resin includes the following components: by weight, 15 to 30 parts of PTFE powder, 5 to 10 parts of PEEK resin containing double bonds, 5 to 10 parts of sodium allyl sulfonate, and 100 parts of dimethylformamide.

[0015] Sealing retaining rings are usually required to have good corrosion resistance and wear resistance. PTFE resin has excellent corrosion resistance (compared to PEEK resin, it has stronger resistance to acid and alkali chemical substances) and wear resistance; carbon fiber is a material with high strength, high modulus and high durability, which is often used for filling and modification of PEEK resin, and can effectively enhance the wear resistance and corrosion resistance of PEEK resin. Therefore, in the present invention, PTFE resin and carbon fiber are used to comprehensively modify PEEK resin to improve the comprehensive performance of PEEK sealing materials. However, considering that the fusion performance of PEEK resin is extremely poor, if it is directly mixed, the performance of the obtained PEEK sealing material is poor, and then the corrosion resistance, wear resistance and sealing of the prepared sealing retaining ring are not good. Therefore, in the present invention, PTFE resin and carbon fiber need to be treated to enhance their compatibility with PEEK resin to obtain PEEK sealing materials with the best comprehensive performance.

[0016] In the present invention, the PEEK resin is first subjected to a hydroxylation treatment; then, it is grafted with acrylic acid to introduce -C=C- into the PEEK resin; finally, it is subjected to initiation polymerization with the PTFE resin subjected to irradiation treatment and heat treatment to obtain a modified PTFE resin having better compatibility with the PEEK resin; wherein, the irradiation treatment and heat treatment of the PTFE resin can increase the peroxy free radicals on its surface, promote the subsequent initiation polymerization, and after the initiation polymerization, can enhance the degree of polymerization between the molecular chains, enhance the mechanical properties of the modified PTFE resin, and further achieve the enhancement of the performance of the PEEK sealing material; further considering that the PEEK resin has poor antistatic properties and can absorb dust, which has a certain influence on the sealing performance of the sealing retaining ring, in the scheme, sodium allyl sulfonate is further added in the initiation polymerization, and a sulfonic acid group is introduced on the chain end of the PTFE resin, which can further improve the compatibility of the PTFE resin with the PEEK resin and also give the PEEK sealing material a certain antistatic property. The modified PTFE resin has good compatibility with the PEEK resin, and can greatly enhance the corrosion resistance and wear resistance of the PEEK sealing material. At the same time, it can also give the PEEK sealing material a certain antistatic property, thereby improving the sealing performance of the sealing retaining ring.

[0017] Furthermore, the preparation method of the modified carbon fiber is as follows: (1) adding carbon fiber and 20-40wt% nitric acid solution into a reaction container, stirring and heating to 60-70°C, stirring and reacting for 2-6 hours, filtering, washing, and drying to obtain oxidized carbon fiber; (2) adding oxidized carbon fiber, silane coupling agent, and anhydrous ethanol into a reaction container, stirring and heating to 60-70°C, stirring and reacting for 2-6 hours, filtering, washing, and drying to obtain modified carbon fiber.

[0018] Furthermore, the ratio of the carbon fiber to the nitric acid solution is 1 g:2 mL.

[0019] Furthermore, the preparation of the modified carbon fiber includes the following components: 20 parts of oxidized carbon fiber, 0.5 to 1 part of silane coupling agent, and 100 parts of anhydrous ethanol, by weight.

[0020] Furthermore, the silane coupling agent is an amino-containing silane coupling agent, specifically including but not limited to any one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-ureapropyltriethoxysilane.

[0021] Considering that carbon fiber has a graphite-like structure, its surface is chemically inert and not easily infiltrated by resin and chemically reacted, so its compatibility with resin is poor, which is not conducive to the preparation of carbon fiber reinforced resin-based composite materials with excellent performance. Therefore, the scheme carries out corresponding modification treatment on carbon fiber: firstly, the carbon fiber is oxidized to increase the polar groups and roughness on the surface of the carbon fiber, and then further grafted with a silane coupling agent containing amino groups to obtain modified carbon fiber; the modified carbon fiber has good compatibility with PEEK resin and can be evenly dispersed in PEEK resin, comprehensively improving the mechanical properties and corrosion resistance of PEEK sealing materials.

[0022] The scheme further utilizes the chemical inertness of carbon fiber and adopts unmodified carbon fiber as a component raw material of PEEK sealing material. It is mainly used as a heterogeneous nucleating agent in PEEK sealing material, which can promote the crystallization of PEEK resin, thereby effectively improving the mechanical properties of PEEK sealing material, so that the wear resistance of the prepared sealing retaining ring is improved.

[0023] Considering that the hardness of PEEK resin will be affected by modified PTFE resin, carbon fiber, etc., the processing performance of PEEK sealing material will be poor, which will also affect the performance of the prepared sealing ring to a certain extent; therefore, methyl vinyl ether-maleic anhydride copolymer is further added to the scheme to adjust the hardness of PEEK sealing material, improve the processing performance, and enhance the relevant performance of the sealing ring.

[0024] Furthermore, the extrusion temperature of the twin-screw extruder is 300-350° C., and the main engine speed is 250-350 r / min.

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] (1) The present invention solves the defect of poor compatibility between PTFE resin and PEEK resin by modifying PTFE resin. By blending PTFE resin with PEEK resin for modification, the corrosion resistance and wear resistance of PEEK sealing material are greatly improved, and at the same time, a certain antistatic property is given to the material.

[0027] (2) The present invention improves the dispersibility of carbon fiber in PEEK resin by modifying the carbon fiber, which can greatly improve the corrosion resistance and wear resistance of PEEK sealing materials;

[0028] (3) In order to further improve the mechanical properties of PEEK, the present invention directly adds part of the unmodified carbon fiber into the PEEK resin and uses it as a heterogeneous nucleating agent to effectively enhance the wear resistance of the PEEK sealing material;

[0029] (4) Considering that the hardness of PEEK resin will be affected by modified PTFE resin, carbon fiber, etc., which will lead to poor processing performance of PEEK sealing materials, methyl vinyl ether-maleic anhydride copolymer is further added as a hardness regulator to modify the processing performance of PEEK sealing materials, so as to obtain a sealing retaining ring with better sealing performance;

[0030] (5) The sealing retaining ring prepared by the PEEK sealing material prepared by the present invention has excellent corrosion resistance, wear resistance and sealing performance. DETAILED DESCRIPTION

[0031] The following is a preferred implementation of the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. For ordinary technicians in this technical field, all other embodiments obtained by ordinary technicians in this field without creative work without departing from the principle of the embodiment of the present invention are within the scope of protection of the present invention.

[0032] Example 1: A method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring:

[0033] Step 1: Preparation of modified PTFE resin: (1) Add 12 parts of PEEK resin, 1.5 parts of sodium borohydride, and 50 parts of dimethyl sulfoxide into a reaction container, stir and heat to 120°C, react for 10 hours, terminate the reaction, filter out the solution, obtain a filter cake, and finally wash it with anhydrous ethanol, 5wt% hydrochloric acid solution, and deionized water in sequence, and dry it to obtain a hydroxylated PEEK resin; (2) After heating a reaction container containing 100 parts of dimethylformamide to 55°C, add 8 parts of hydroxylated PEEK resin, 0.23 parts of 4-dimethylaminopyridine, and 18 parts of N,N'-dicyclohexylcarbodiimide, and then ultrasonically disperse it for 15 minutes, then add 15 parts of acrylic acid, stir in the dark for 18 hours, terminate the reaction, and finally filter out the solution. Obtain a filter cake, wash it with anhydrous ethanol and deionized water in turn, dry and grind it to obtain a PEEK resin containing double bonds; (3) First, irradiate and crack 30 parts of PTFE resin under irradiation conditions of 2000 kGy, then add it to anhydrous ethanol, stir and heat to 180°C, keep warm for 10 hours, finally wash it with deionized water, dry and grind it to obtain PTFE powder; (4) Add 8 parts of PEEK resin containing double bonds, 25 parts of PTFE powder, 8 parts of sodium allyl sulfonate, and 100 parts of dimethylformamide into a reaction container, stir and heat to 55°C, continue stirring for 3 hours, and then, under stirring, use 365nm ultraviolet light to initiate polymerization for 40 minutes, terminate the reaction, and obtain a modified PTFE resin;

[0034] Step 2: Preparation of modified carbon fiber: (1) Add 25 parts (250 g) of carbon fiber and 500 mL of 40 wt% nitric acid solution into a reaction container, stir and heat to 65°C, stir and react for 5 hours, filter, wash and dry to obtain oxidized carbon fiber; (2) Add 20 parts of oxidized carbon fiber, 0.8 parts of γ-aminopropyltrimethoxysilane and 100 parts of anhydrous ethanol into a reaction container, stir and heat to 65°C, stir and react for 5 hours, filter, wash and dry to obtain modified carbon fiber;

[0035] Step 3: Add 60 parts of PEEK resin, 17 parts of modified PTFE resin, 12 parts of modified carbon fiber, 8 parts of methyl vinyl ether-maleic anhydride copolymer, 6 parts of carbon fiber, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0036] Example 2: A method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring:

[0037] Step 1: Preparation of modified PTFE resin: (1) Add 12 parts of PEEK resin, 1.5 parts of sodium borohydride, and 50 parts of dimethyl sulfoxide into a reaction container, stir and heat to 120°C, react for 10 hours, terminate the reaction, filter out the solution, obtain a filter cake, and finally wash it with anhydrous ethanol, 5wt% hydrochloric acid solution, and deionized water in sequence, and dry it to obtain a hydroxylated PEEK resin; (2) After heating a reaction container containing 100 parts of dimethylformamide to 55°C, add 5 parts of hydroxylated PEEK resin, 0.23 parts of 4-dimethylaminopyridine, and 18 parts of N,N'-dicyclohexylcarbodiimide, and then ultrasonically disperse it for 15 minutes, then add 15 parts of acrylic acid, stir and react in the dark for 18 hours, terminate the reaction, and finally filter out the solution. , obtain a filter cake, wash it with anhydrous ethanol and deionized water in turn, dry and grind it to obtain a PEEK resin containing double bonds; (3) first irradiate and crack 30 parts of PTFE resin under 500 kGy irradiation conditions, then add it to anhydrous ethanol, stir and heat to 150°C, keep warm for 6 hours, finally wash it with deionized water, dry and grind it to obtain PTFE powder; (4) add 5 parts of PEEK resin containing double bonds, 25 parts of PTFE powder, 5 parts of sodium allyl sulfonate, and 100 parts of dimethylformamide into a reaction container, stir and heat to 55°C, continue stirring for 3 hours, and then, under stirring, use 365nm ultraviolet light to initiate polymerization for 40 minutes, terminate the reaction, and obtain a modified PTFE resin;

[0038] Step 2: Preparation of modified carbon fiber: (1) Add 25 parts (250 g) of carbon fiber and 500 mL of 20 wt% nitric acid solution into a reaction container, stir and heat to 60°C, stir and react for 2 hours, filter, wash and dry to obtain oxidized carbon fiber; (2) Add 20 parts of oxidized carbon fiber, 0.5 parts of γ-aminopropyltrimethoxysilane and 100 parts of anhydrous ethanol into a reaction container, stir and heat to 60°C, stir and react for 2 hours, filter, wash and dry to obtain modified carbon fiber;

[0039] Step 3: Add 60 parts of PEEK resin, 17 parts of modified PTFE resin, 12 parts of modified carbon fiber, 8 parts of methyl vinyl ether-maleic anhydride copolymer, 6 parts of carbon fiber, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0040] Example 3: A method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring:

[0041] Step 1: Preparation of modified PTFE resin: (1) Add 12 parts of PEEK resin, 1.5 parts of sodium borohydride, and 50 parts of dimethyl sulfoxide into a reaction container, stir and heat to 120°C, react for 10 hours, terminate the reaction, filter out the solution, obtain a filter cake, and finally wash it with anhydrous ethanol, 5wt% hydrochloric acid solution, and deionized water in sequence, and dry it to obtain a hydroxylated PEEK resin; (2) After heating a reaction container containing 100 parts of dimethylformamide to 55°C, add 10 parts of hydroxylated PEEK resin, 0.23 parts of 4-dimethylaminopyridine, and 18 parts of N,N'-dicyclohexylcarbodiimide, and then ultrasonically disperse it for 15 minutes, then add 15 parts of acrylic acid, stir in the dark for 18 hours, terminate the reaction, and finally filter out the solution to obtain The filter cake is washed with anhydrous ethanol and deionized water in turn, dried and ground to obtain a PEEK resin containing double bonds; (3) 30 parts of PTFE resin are irradiated and cracked under irradiation conditions of 3500 kGy, then added to anhydrous ethanol, stirred and heated to 180°C, kept warm for 10 hours, and finally washed with deionized water, dried and ground to obtain PTFE powder; (4) 10 parts of PEEK resin containing double bonds, 25 parts of PTFE powder, 10 parts of sodium allyl sulfonate, and 100 parts of dimethylformamide are added to a reaction container, stirred and heated to 55°C, and then stirred for 3 hours, and then, under stirring, 365 nm ultraviolet light is used to initiate polymerization for 40 minutes, and the reaction is terminated to obtain a modified PTFE resin;

[0042] Step 2: Preparation of modified carbon fiber: (1) Add 25 parts (250 g) of carbon fiber and 500 mL of 40 wt% nitric acid solution into a reaction container, stir and heat to 70°C, stir and react for 6 hours, filter, wash and dry to obtain oxidized carbon fiber; (2) Add 20 parts of oxidized carbon fiber, 1 part of γ-aminopropyltrimethoxysilane and 100 parts of anhydrous ethanol into a reaction container, stir and heat to 70°C, stir and react for 6 hours, filter, wash and dry to obtain modified carbon fiber;

[0043] Step 3: Add 60 parts of PEEK resin, 17 parts of modified PTFE resin, 12 parts of modified carbon fiber, 8 parts of methyl vinyl ether-maleic anhydride copolymer, 6 parts of carbon fiber, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0044] Based on Example 1, Examples 4 to 5 and Comparative Examples 1 to 5 are provided, as described below:

[0045] Example 4: Example 4 is based on Example 1, and the following adjustments are made: the amount of modified PTFE resin in the raw material components of the corrosion-resistant PEEK sealing material for the sealing retaining ring; other processes remain unchanged, specifically:

[0046] Step 3: Add 60 parts of PEEK resin, 10 parts of modified PTFE resin, 12 parts of modified carbon fiber, 8 parts of methyl vinyl ether-maleic anhydride copolymer, 6 parts of carbon fiber, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0047] Example 5: Example 5 is based on Example 1, and the following adjustments are made: the amount of modified carbon fiber in the raw material components of the corrosion-resistant PEEK sealing material for the sealing retaining ring; other processes remain unchanged, specifically:

[0048] Step 3: Add 60 parts of PEEK resin, 17 parts of modified PTFE resin, 5 parts of modified carbon fiber, 8 parts of methyl vinyl ether-maleic anhydride copolymer, 6 parts of carbon fiber, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0049] Comparative Example 1: Comparative Example 1 is based on Example 1, with the following adjustments: the PTFE resin is not modified, and other processes remain unchanged, specifically:

[0050] Step 3: Add 60 parts of PEEK resin, 17 parts of PTFE resin, 12 parts of modified carbon fiber, 8 parts of methyl vinyl ether-maleic anhydride copolymer, 6 parts of carbon fiber, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0051] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustments: no modification treatment is performed on the carbon fiber, and other processes remain unchanged, specifically:

[0052] Step 3: Add 60 parts of PEEK resin, 17 parts of modified PTFE resin, 8 parts of methyl vinyl ether-maleic anhydride copolymer, 18 parts of carbon fiber, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0053] Comparative Example 3: Comparative Example 3 is based on Example 1, with the following adjustments: no carbon fiber is added, and other processes remain unchanged, specifically:

[0054] Step 3: Add 60 parts of PEEK resin, 17 parts of modified PTFE resin, 18 parts of modified carbon fiber, 8 parts of methyl vinyl ether-maleic anhydride copolymer, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0055] Comparative Example 4: Comparative Example 4 is based on Example 1, with the following adjustments: methyl vinyl ether-maleic anhydride copolymer is not added, and other processes remain unchanged, specifically:

[0056] Step 3: Add 60 parts of PEEK resin, 17 parts of modified PTFE resin, 12 parts of modified carbon fiber, 6 parts of carbon fiber, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0057] Comparative Example 5: Comparative Example 5 is based on Example 1, with the following adjustments: PTFE resin and carbon fiber are not modified; specifically:

[0058] Step 3: Add 60 parts of PEEK resin, 17 parts of PTFE resin, 18 parts of carbon fiber, 8 parts of methyl vinyl ether-maleic anhydride copolymer, and 2 parts of lubricant into a twin-screw extruder, mix evenly, and extrude and granulate at 345°C and a speed of 300r / min to obtain a corrosion-resistant PEEK sealing material for a sealing ring.

[0059] In the above embodiments, all raw materials are from the following sources: PEEK resin with a purity of 99%, CAS number: 29658-26-2, item number: JSPL-PEEK-001, purchased from Jiangsu Puli New Materials Co., Ltd.; PTFE resin with a purity of 99%, CAS number: 9002-84-0, sodium borohydride with a purity of 99%, dimethylformamide with a purity of 99%, all purchased from Shanghai Jinjinle Industrial Co., Ltd.; dimethyl sulfoxide with a purity of 99%, 4-dimethylaminopyridine with a purity of 99%, N,N'-dicyclohexylcarbodiimide with a purity of 99%, Sodium allyl sulfonate with a purity of 99.5%, γ-aminopropyltrimethoxysilane with a purity of 99%, and methyl vinyl ether-maleic anhydride copolymer with a purity of 99%, CAS number: 9011-16-9, were all purchased from Hubei Jusheng Technology Co., Ltd.; acrylic acid with a purity of 99% was purchased from Hunan Maigao New Materials Technology Co., Ltd.; carbon fiber with a purity of 99%, a size of 100nm×20~50μm, was purchased from Jiangsu Boshi Carbon Fiber Technology Co., Ltd.; lubricant brand LX97024 was purchased from Suzhou Xinsuyu Plastic Raw Materials Co., Ltd.; each portion was 10g.

[0060] Performance test: The sealing rings prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were uniformly processed into specimens with a length of 10 cm × a width of 5 cm × a height of 3 cm using corrosion-resistant PEEK sealing materials for corrosion resistance test. The specific test method is: at room temperature, the specimens were immersed in 98% concentrated sulfuric acid for 24 hours, then taken out and dried, and the wear resistance before and after corrosion was tested; wherein the wear resistance was tested according to the standard of GB / T 3960-2016, and the specific data are shown in Table 1 below:

[0061] Table 1

[0062]

[0063] Result analysis: From the data in Table 1 above, it can be seen that the modification treatment of PTFE resin and carbon fiber in the present invention significantly enhances their compatibility in PEEK resin, and cooperates with carbon fiber and methyl vinyl ether-maleic anhydride copolymer to enhance the corrosion resistance and wear resistance of PEEK resin, and finally comprehensively prepares a PEEK sealing material with excellent corrosion resistance and wear resistance.

[0064] Finally, it should be noted that the above is only a preferred embodiment of the present invention, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the spirit and principle of the present invention and within the technical scope disclosed in this application should be included in the protection scope of this application; in the absence of conflict, the embodiments of this application and the features in the embodiments can be combined with each other. Therefore, the protection scope of this application shall be based on the protection scope of the claims.

Claims

1. A method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring, characterized in that: The following steps are involved: Step 1: Ultraviolet irradiation initiates polymerization of PEEK resin containing double bonds, PTFE powder, and sodium allyl sulfonate to obtain modified PTFE resin; Step 2: Grafting the oxidized carbon fiber with a silane coupling agent to obtain a modified carbon fiber; Step 3: Add PEEK resin, modified PTFE resin, modified carbon fiber, methyl vinyl ether-maleic anhydride copolymer, carbon fiber, and lubricant into a twin-screw extruder, mix evenly, extrude and granulate, and obtain a corrosion-resistant PEEK sealing material for a sealing retaining ring.

2. The method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring according to claim 1, characterized in that: The preparation method of the modified PTFE resin is: (1) PEEK resin, sodium borohydride and dimethyl sulfoxide are added to a reaction container, stirred and heated to 115-125° C., reacted for 6-12 hours, terminated the reaction, filtered out the solution, obtained a filter cake, and finally washed with anhydrous ethanol, hydrochloric acid solution and deionized water in sequence, and dried to obtain a hydroxylated PEEK resin; (2) After heating the reaction vessel containing dimethylformamide to 45-60° C., hydroxylated PEEK resin, 4-dimethylaminopyridine, and N,N'-dicyclohexylcarbodiimide are added thereto, and then ultrasonically dispersed for 10-20 minutes, and then acrylic acid is added, and the reaction is stirred for 12-24 hours in a dark environment, and the reaction is terminated. Finally, the solution is filtered out to obtain a filter cake, which is washed with anhydrous ethanol and deionized water in turn, and then dried and ground to obtain a PEEK resin containing double bonds; (3) firstly irradiating and cracking the PTFE resin under irradiation conditions of 500 to 3500 kGy, then adding it to anhydrous ethanol, stirring and heating it to 150 to 200° C., keeping it warm for 6 to 12 hours, and finally washing it with deionized water, and then drying and grinding it to obtain PTFE micropowder; (4) PEEK resin containing double bonds, PTFE powder, sodium allyl sulfonate and dimethylformamide are added into a reaction vessel, and after stirring and heating to 45-60° C., stirring is continued for 1-3 hours, and then, under stirring, polymerization is initiated by 365 nm ultraviolet light irradiation for 30-60 minutes, and the reaction is terminated to obtain a modified PTFE resin.

3. The method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring according to claim 2, characterized in that: The preparation of the hydroxylated PEEK resin includes the following components: by weight, 6 to 12 parts of PEEK resin, 1 to 2 parts of sodium borohydride, and 50 parts of dimethyl sulfoxide; the preparation of the double-bond-containing PEEK resin includes the following components: by weight, 5 to 10 parts of hydroxylated PEEK resin, 15 parts of acrylic acid, 0.15 to 0.3 parts of 4-dimethylaminopyridine, 15 to 20 parts of N,N'-dicyclohexylcarbodiimide, and 100 parts of dimethylformamide.

4. The method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring according to claim 2, characterized in that: The preparation of the modified PTFE resin comprises the following components: by weight, 15 to 30 parts of PTFE micropowder, 5 to 10 parts of PEEK resin containing double bonds, 5 to 10 parts of sodium allyl sulfonate, and 100 parts of dimethylformamide.

5. The method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring according to claim 1, characterized in that: The preparation method of the modified carbon fiber is: (1) adding carbon fiber and 20-40 wt% nitric acid solution into a reaction container, stirring and heating to 60-70° C., stirring and reacting for 2-6 hours, filtering, washing and drying to obtain oxidized carbon fiber; (2) Add oxidized carbon fiber, silane coupling agent and anhydrous ethanol into a reaction container, stir and heat to 60-70° C., stir and react for 2-6 hours, filter, wash and dry to obtain modified carbon fiber.

6. The method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring according to claim 5, characterized in that: The ratio of the carbon fiber to the nitric acid solution is 1 g:2 mL.

7. The method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring according to claim 5, characterized in that: The preparation of the modified carbon fiber includes the following components: 20 parts of oxidized carbon fiber, 0.5 to 1 part of silane coupling agent, and 100 parts of anhydrous ethanol, calculated by weight.

8. The method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring according to claim 7, characterized in that: The silane coupling agent is an amino-containing silane coupling agent, specifically including any one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-ureapropyltriethoxysilane.

9. The method for preparing a corrosion-resistant PEEK sealing material for a sealing retaining ring according to claim 1, characterized in that: The extrusion temperature of the twin-screw extruder is 300-350° C., and the main engine speed is 250-350 r / min.

10. The corrosion-resistant PEEK sealing material for sealing retaining ring prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The invention comprises the following components: by weight, 50-65 parts of PEEK resin, 10-20 parts of modified PTFE resin, 5-15 parts of modified carbon fiber, 5-10 parts of methyl vinyl ether-maleic anhydride copolymer, 5-10 parts of carbon fiber and 1-3 parts of lubricant.

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