Corrosion-resistant tetrafluoro-propylene rubber sealing material for harsh environment of oil and gas field and preparation method and application thereof

Abstract

This invention discloses a corrosion-resistant tetrapropylene fluororubber sealing material for harsh environments in oil and gas fields, its preparation method, and its application. The sealing material is composed of the following components in parts by weight: 100 parts of tetrapropylene fluororubber raw rubber, 4-10 parts of methacryloxypropyl cage-like polysilsesquioxane, 1-3 parts of peroxide primary crosslinking agent, 30-60 parts of reinforcing filler, and 2-10 parts of processing aid. This invention uses methacryloxypropyl cage-like polysilsesquioxane as a co-crosslinking agent. Its inorganic Si-O-Si cage-like skeleton fundamentally eliminates the technical defects of traditional ester-based co-crosslinking agents, which are prone to hydrolysis, significantly improving the chemical stability of the crosslinking network in high-temperature acidic media. Combined with the synergistic effect of the reinforcing filler, the resulting material can meet the sealing requirements of harsh conditions such as high temperature, high pressure, and multi-media corrosion in oil and gas fields. The preparation process is simple and suitable for industrial production.

Description

Technical Field

[0001] This invention relates to a corrosion-resistant tetrafluoroethylene rubber sealing material for harsh environments in oil and gas fields, its preparation method and application, belonging to the field of special rubber materials technology. Background Technology

[0002] As oil and gas field development moves towards deeper, more complex blocks with high sulfur content, high temperature and high pressure, the downhole working environment becomes increasingly harsh. Sealing materials face severe challenges from the combined corrosion of multiple factors, including high temperature (up to 230°C or higher), high pressure (up to 140MPa), hydrogen sulfide (H2S), carbon dioxide (CO2), acid and alkali media, and crude oil.

[0003] Tetrafluoropropylene rubber (AFLAS) possesses excellent chemical stability and heat resistance due to the large number of high-energy CF bonds in its molecular backbone, making it a preferred matrix for sealing materials in oil and gas fields. However, its molecular chain lacks effective cross-linking sites, resulting in low cross-linking efficiency and insufficient mechanical properties. Furthermore, in the harsh environment of oil and gas fields, the cross-linking network of traditional vulcanization systems is easily damaged by acidic media (such as H2S and HCl), alkaline media (such as NaOH), and oily media, leading to a decline in the mechanical properties of the sealing material, excessive volume deformation, and ultimately, sealing failure, causing safety hazards such as oil and gas leaks.

[0004] In existing technologies, the commonly used crosslinking agents for tetrapropylene fluororubber (such as TAIC and TMPTA) are mostly ester compounds, which are easily decomposed in acidic and alkaline environments, resulting in poor stability of the crosslinked network. Simultaneously, the reinforcing effect of a single filler is limited, and the interfacial bonding between the filler and the rubber matrix is ​​poor, easily leading to interfacial delamination in corrosive environments, further reducing the material's corrosion resistance. Therefore, developing a tetrapropylene fluororubber sealing material that combines a stable crosslinked structure, excellent mechanical properties, and strong resistance to harsh media corrosion is of great significance for ensuring the safe and efficient development of oil and gas fields. Summary of the Invention

[0005] To address the technical shortcomings of existing tetrafluoropropylene rubber (TEBR) which suffers from easy hydrolysis and destruction of its crosslinking network and short sealing life in high-temperature, high-pressure, and acidic media due to the use of ester-based co-crosslinking agents, this invention aims to provide a novel TEBR sealing material. By constructing a stable crosslinking network based on a specific cage-like silsesquioxane, the long-term stability of the material in harsh corrosive environments is fundamentally improved, thereby solving the problem of easy failure of existing sealing materials under high-temperature, high-pressure, and high-sulfur / carbon dioxide oil and gas field conditions.

[0006] The corrosion-resistant tetrafluoroethylene rubber sealing material for harsh oil and gas field environments provided by this invention is made from the following raw materials in parts by weight: 100 parts of raw tetrapropylene fluororubber (uncured tetrapropylene fluororubber raw material); 4-10 parts of cage-type silsesquioxane co-crosslinking agent; 1-3 parts of peroxide main crosslinking agent; 30-60 parts of reinforcing filler; Processing aids 2-10 parts; The cage-like silsesquioxane co-crosslinking agent is methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS), which is a type of compound with a Si-O-Si inorganic cage-like framework. In this invention, MAPOSS forms a "DCP / MAPOSS stable crosslinking system" with a peroxide main crosslinking agent (such as DCP). DCP initiates the generation of free radicals in the rubber macromolecular chains, and the multiple double bonds on MAPOSS act as "bridges," efficiently connecting these free radicals to form a three-dimensional network structure with ultra-high stability, using a robust MAPOSS inorganic cage as the "crosslinking center." MAPOSS is the chemical basis for the "extraordinary corrosion resistance" of this invention. Based on its unique "inorganic cage + organic arm" structure, tetrafluoroethylene propylene rubber sealing materials can truly withstand the harsh conditions of high temperature, high pressure, and multi-media corrosion in oil and gas fields.

[0007] Preferably, the amount of the cage-type silsesquioxane co-crosslinking agent is 6-8 parts.

[0008] Preferably, the peroxide main crosslinking agent is dicumyl peroxide (DCP).

[0009] Preferably, the reinforcing filler is carbon black and / or carbon nanotubes; The carbon black is preferably medium-particle furnace carbon black N550; The carbon nanotubes are preferably modified with silane coupling agents. The modification steps are as follows: After the carbon nanotubes are purified and pretreated with strong acid, they are dispersed in an ethanol / water mixed solution of silane coupling agent and impregnated at a certain temperature (60-80℃) for 2-6 hours. This allows the silanol produced by the hydrolysis of the silane coupling agent to undergo a condensation reaction with the active groups on the surface of the carbon nanotubes. After the reaction is completed, the carbon nanotubes are separated, washed and dried to obtain modified carbon nanotubes with silane coupling agents grafted on their surface. The strong acid may be concentrated sulfuric acid, concentrated nitric acid, or a mixture thereof; The silane coupling agent may be γ-aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), or γ-(methacryloyloxy)propyltrimethoxysilane (KH570).

[0010] Furthermore, the reinforcing filler is preferably a mixture of medium particle furnace black N550 and carbon nanotubes modified with silane coupling agent; The silane coupling agent modified carbon nanotubes have the following effects: improving the dispersibility of carbon nanotubes in rubber, enhancing the interfacial bonding force between carbon nanotubes and tetrafluoroethylene rubber matrix, and significantly improving the tensile strength and heat resistance of composite materials.

[0011] The mixture of medium-particle furnace carbon black N550 and silane coupling agent-modified carbon nanotubes has the following effects: constructing a "sphere-fiber" dual-network reinforcement structure to simultaneously improve mechanical properties (hardness, tensile strength) and corrosion resistance; forming a dense filler network to effectively block corrosive media (H). + Cl - It can reduce the volume swelling rate of materials in acid, alkali, oil and H2S / CO2 environments and extend the service life of seals under harsh working conditions.

[0012] Preferably, the processing aid includes one or more of surfactants, antioxidants, and plasticizers; preferably, the processing aid includes calcium stearate and / or zinc oxide.

[0013] The present invention further provides a method for preparing the corrosion-resistant tetrafluoroethylene rubber sealing material, comprising the following steps: S1. Plasticize the raw tetrapropylene fluororubber; S2. Add cage-type silsesquioxane co-crosslinking agent, reinforcing filler and processing aid to the plasticized raw rubber, and mix to obtain compound rubber. S3. Add peroxide main crosslinking agent to the compound, continue to mix evenly and then sheet out; S4. The rubber compound after sheeting is vulcanized to obtain the tetrafluoroethylene rubber sealing material.

[0014] In step S4, the vulcanization includes a first-stage vulcanization and a second-stage vulcanization; the temperature of the first-stage vulcanization is 160-180℃, the pressure is 10-15MPa, and the vulcanization time is the positive vulcanization time t90 of the compound, where t90 refers to the time required to reach 90% of the maximum torque on the vulcanization curve, measured by a rotorless vulcanizer; the temperature of the second-stage vulcanization is 180-220℃, and the time is 12-24 hours.

[0015] The corrosion-resistant tetrafluoroethylene rubber sealing material provided by this invention can be used to manufacture seals for downhole tools in oil and gas fields; The oil and gas field downhole tool seals may be packer sleeves, blowout preventer cores, or valve seals. The application environment is a medium containing hydrogen sulfide and / or carbon dioxide; The application environment has a temperature of 150-230℃ and a pressure of 30-120MPa.

[0016] Compared with the prior art, the present invention has the following significant advantages: (1) Optimization of crosslinking system: Methacryloxypropyl cage-like polysilsesquioxane was selected as a co-crosslinking agent. Its molecular structure contains 8 double bonds, which can synergistically initiate crosslinking of tetrafluoroethylene rubber with DCP and improve the crosslinking density. Moreover, its stable inorganic Si-O-Si cage-like core completely replaces the easily hydrolyzed ester bond (COC) in traditional co-crosslinking agents such as TAIC, eliminating the weak link attacked by high temperature acidic medium from the molecular structure and greatly improving the stability of the entire rubber network skeleton.

[0017] (2) Reinforcing system design: N550 carbon black and silane-modified carbon nanotubes are used together as reinforcing fillers. N550 carbon black can improve the mechanical properties and corrosion resistance of rubber, while silane-modified carbon nanotubes can further enhance the tensile strength and heat resistance of the material. Moreover, the two have good interface bonding with the rubber matrix, which can reduce the erosion of the interface by corrosive media.

[0018] (3) Improved corrosion resistance: The cage-like structure of MAPOSS can protect the rubber molecular chains and reduce the penetration of corrosive media; the synergistic effect of N550 carbon black and carbon nanotubes can reduce the swelling rate of the material and improve its stability in H2S / CO2, acid and alkali and oily media. While achieving extraordinary corrosion resistance, the material of this invention maintains excellent conventional physical and mechanical properties (high hardness, high tensile strength, suitable elongation) and good processing performance, which can meet the manufacturing requirements of complex-shaped seals.

[0019] The material design of this invention is directly aimed at the extreme corrosive conditions encountered in the deep and ultra-deep exploitation of oil and gas fields, solving the long-standing technical pain points of short life and poor reliability of sealing materials in this field. The prepared sealing components can significantly improve the sealing reliability and service life of key downhole tools such as packers under harsh environments such as high temperature, high pressure and corrosion. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. It should be noted that the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] This invention provides a corrosion-resistant tetrapropylene fluororubber sealing material for harsh environments in oil and gas fields, comprising, by weight, the following components: 100 parts of tetrapropylene fluororubber raw rubber, 4-10 parts of methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS), 1-3 parts of peroxide main crosslinking agent, 30-60 parts of reinforcing filler, and 2-10 parts of processing aids. The preparation method includes: plasticizing, mixing (adding the crosslinking aid, filler, and main crosslinking agent in stages), sheeting, and two-stage vulcanization (first stage at 160-180℃, second stage at 180-220℃).

[0022] This invention uses MAPOSS as a co-crosslinking agent. Its inorganic Si-O-Si cage-like framework completely eliminates the defect of easy hydrolysis of traditional ester bonds, significantly improving the stability of the crosslinked network in high-temperature acidic media. The resulting sealing material exhibits high mechanical property retention and small volume change after corrosion in 10% HCl and simulated H2S / CO2 environments. It also possesses excellent tensile strength and thermal stability, meeting the long-term sealing requirements of high-temperature, high-pressure, and multi-media corrosion conditions in oil and gas fields. Furthermore, the preparation process is simple and suitable for industrial production.

[0023] Example 1: Corrosion-resistant tetrafluoroethylene rubber sealing material for harsh oil and gas field environments 100 parts by weight of tetrafluoroethylene rubber (AFLAS 100S), 8 parts by weight of methacryloyloxypropyl cage polysilsesquioxane (MAPOSS), 3 parts by weight of dicumyl peroxide (DCP), 25 parts by weight of carbon black N550, 5 parts by weight of silane-modified carbon nanotubes, 1 part by weight of calcium stearate, and 5 parts by weight of zinc oxide.

[0024] The silane-modified carbon nanotubes were prepared by the following method: carbon nanotubes were purified and pretreated with a 1:3 mixture of concentrated nitric acid and concentrated sulfuric acid (volume ratio), then dispersed in a KH550 ethanol / water mixture and impregnated at 60°C for 5 hours. This allowed the silanol produced by the hydrolysis of the silane coupling agent to undergo a condensation reaction with the active groups on the surface of the carbon nanotubes. After the reaction was completed, the nanotubes were separated, washed, and dried to obtain the modified carbon nanotubes with silane coupling agent grafted onto their surface.

[0025] The preparation method of corrosion-resistant tetrafluoroethylene rubber sealing material includes the following steps: 1. Mix the tetrafluoropropylene rubber raw rubber, MAPOSS and DCP on a two-roll mill at a mixing temperature of 70°C to obtain a premixed rubber compound. 2. Place the premixed rubber compound, carbon black N550, modified carbon nanotubes, calcium stearate and zinc oxide in a mixer and mix them evenly at 90°C. After discharging the rubber, pass it through a two-roll mill to produce a thin sheet to obtain the compounded rubber. 3. The compound rubber is subjected to a first-stage compression molding and vulcanization at a temperature of 170℃, a pressure of 15MPa, and a time of 15min. Then, a second-stage vulcanization is carried out. The first-stage vulcanized product is placed in an oven, heated to 200℃ and maintained for 24h. After cooling, the corrosion-resistant tetrafluoroethylene rubber sealing material is obtained.

[0026] Example 2: Corrosion-resistant tetrafluoroethylene rubber sealing material for harsh oil and gas field environments 100 parts by weight of tetrafluoroethylene rubber (AFLAS 100S), 6 parts by weight of methacryloyloxypropyl cage polysilsesquioxane (MAPOSS), 2.5 parts by weight of dicumyl peroxide (DCP), 30 parts by weight of carbon black N550, 1 part by weight of calcium stearate, and 5 parts by weight of zinc oxide.

[0027] The preparation method is the same as in Example 1.

[0028] Example 3: Corrosion-resistant tetrafluoroethylene rubber sealing material for harsh oil and gas field environments 100 parts by weight of tetrafluoroethylene rubber (AFLAS 100S), 8 parts by weight of methacryloyloxypropyl cage polysilsesquioxane (MAPOSS), 3 parts by weight of dicumyl peroxide (DCP), 20 parts by weight of carbon black N550, 8 parts by weight of silane-modified carbon nanotubes, 1 part by weight of calcium stearate, and 5 parts by weight of zinc oxide.

[0029] The preparation method is the same as in Example 1.

[0030] Example 4: Corrosion-resistant tetrafluoroethylene rubber sealing material for harsh oil and gas field environments 70 parts by weight of tetrafluoropropylene rubber raw material (AFLAS 100S), 30 parts by weight of tetrafluoropropylene rubber raw material (AFLAS 100H), 8 parts by weight of methacryloyloxypropyl cage polysilsesquioxane (MAPOSS), 3 parts by weight of dicumyl peroxide (DCP), 25 parts by weight of carbon black N550, 5 parts by weight of silane-modified carbon nanotubes, 1 part by weight of calcium stearate, and 5 parts by weight of zinc oxide.

[0031] The preparation method is the same as in Example 1.

[0032] Comparative Example 1 Replace “8 parts by weight of methacryloyloxypropyl cage polysilsesquioxane (MAPOSS)” in Example 1 with “8 parts by weight of triallyl isocyanurate (TAIC)”, and the remaining components and preparation methods are the same as in Example 1.

[0033] Comparative Example 2 Replace “25 parts by weight of carbon black N550 and 5 parts by weight of silane-modified carbon nanotubes” in Example 1 with “30 parts by weight of carbon black N774”, and keep the other components and preparation methods the same as in Example 1.

[0034] Comparative Example 3 Remove "8 parts by weight of methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS)" from Example 1, and the remaining components and preparation method are the same as in Example 1.

[0035] Comparative Example 4 Replace “8 parts by weight of methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS)” in Example 1 with “2 parts by weight of methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS)”, and the remaining components and preparation methods are the same as in Example 1.

[0036] Comparative Example 5 Replace “8 parts by weight of methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS)” in Example 1 with “12 parts by weight of methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS)”, and the remaining components and preparation methods are the same as in Example 1.

[0037] Comparative Example 6 Replace "5 parts by weight of silane-modified carbon nanotubes" in Example 1 with "5 parts by weight of unmodified carbon nanotubes", and keep the other components and preparation methods the same as in Example 1.

[0038] Comparative Example 7 Replace “8 parts by weight of methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS)” in Example 1 with “8 parts by weight of acryloyloxypropyl cage-like polysilsesquioxane (AOPOSS)”, and the remaining components and preparation methods are the same as in Example 1.

[0039] Table 1. Components of Examples and Comparative Examples

[0040] Test case The corrosion-resistant tetrafluoropropylene rubber sealing materials prepared in Examples 1-4 and Comparative Examples 1-7 were subjected to performance tests according to the standards and methods listed in Table 2.

[0041] Table 2 Performance Testing Standards and Methods

[0042] The test results are shown in Table 3: Table 3 Performance Test Results

[0043] The performance test results in Table 3 clearly show that: Compared to Comparative Example 1, which uses a traditional triallyl isocyanurate (TAIC) crosslinking system, the corrosion-resistant tetrafluoroethylene rubber sealing materials based on methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS) provided in Examples 1-4 of this invention exhibit a significant advantage in tensile strength retention after corrosion with 10% hydrochloric acid (75% in Example 1, compared to only 48% in Comparative Example 1). Their volume stability under simulated H2S / CO2 synergistic corrosion conditions is also greatly improved (8.2% volume change in Example 1, compared to 15.6% in Comparative Example 1). This demonstrates that the crosslinking network constructed with MAPOSS possesses superior chemical stability in harsh acidic environments.

[0044] Compared to Comparative Example 2, which uses a conventional carbon black N774 reinforcement system, the N550 carbon black and silane-modified carbon nanotube synergistic reinforcement system used in this embodiment of the invention also exhibits superior performance in terms of room temperature tensile strength (27.5 MPa in Example 1, 22.7 MPa in Comparative Example 2) and the aforementioned synergistic corrosion resistance volume stability. This indicates that the optimized reinforcement system can more effectively resist the physical swelling and penetration of the medium.

[0045] Compared to Comparative Example 3, which did not contain any crosslinking agent, the corrosion-resistant tetrafluoroethylene rubber sealing materials based on methacryloyloxypropyl cage-like polysilsesquioxane (MAPOSS) provided in Examples 1-4 of this invention exhibit overwhelming advantages in room temperature tensile strength (27.5 MPa in Example 1, only 18.5 MPa in Comparative Example 3), strength retention after heat aging (72% in Example 1, 55% in Comparative Example 3), and acid corrosion resistance (75% strength retention after hydrochloric acid corrosion and 8.2% volume change after H2S / CO2 corrosion in Example 1, compared to 35% and 22.0% in Comparative Example 3, respectively). This demonstrates that MAPOSS, as a crosslinking agent, is an indispensable core component for constructing a high-strength, stable, and corrosion-resistant crosslinking network.

[0046] Compared to Comparative Example 4, which used 2 parts of MAPOSS (below the range required by this invention), Examples 1-4 of this invention are significantly superior in all aspects of performance. For example, the strength retention rate after hydrochloric acid corrosion in Example 1 (75%) is much higher than that in Comparative Example 4 (58%), and the volume stability after simulated H2S / CO2 synergistic corrosion (volume change rate of 8.2% in Example 1) is also significantly better than that in Comparative Example 4 (18.5%). This indicates that insufficient MAPOSS dosage cannot form a sufficiently dense and stable cross-linked network, thus confirming the necessity of the lower limit of the 4-10 parts dosage range in this invention.

[0047] Compared to Comparative Example 5, which used 12 parts of MAPOSS (exceeding the range required by this invention), Examples 1-4 of this invention exhibited superior long-term durability while maintaining excellent initial mechanical properties. Although the initial hardness of Comparative Example 5 was comparable to that of Example 1, its volume change rate (14.0%) under harsh corrosive environments was significantly higher than that of Example 1 (8.2%), and its strength retention rate after heat aging (66%) was also lower than that of Example 1 (72%). This demonstrates that excessive MAPOSS may lead to uneven dispersion or agglomeration in the matrix, which is detrimental to the stability of long-term performance, highlighting the rationality of the upper limit of the dosage range of this invention.

[0048] Compared to Comparative Example 6, which used unmodified carbon nanotubes as reinforcing fillers, the silane-modified carbon nanotube and N550 carbon black synergistic reinforcement system used in this embodiment of the invention exhibits significant advantages in resisting media penetration. The volume change rate of Comparative Example 6 after simulated H2S / CO2 corrosion was 16.5%, while that of Example 1 was 8.2%. This indicates that silane modification effectively improves the interfacial bonding between carbon nanotubes and the rubber matrix, forming a denser anti-permeation barrier, thereby significantly enhancing the material's resistance to swelling and corrosion.

[0049] Compared to Comparative Example 7, which used acryloyloxy cage-like polysilsesquioxane (AOPOSS) as a co-crosslinking agent, the MAPOSS-based systems of Examples 1-4 of this invention exhibit unique advantages in the crucial aspect of acid corrosion resistance. The tensile strength retention rate (52%) of Comparative Example 7 after hydrochloric acid corrosion was significantly lower than that of Example 1 (75%). This demonstrates that the methyl group on the R group in MAPOSS plays a crucial protective role in the double bond crosslinking points, enabling it to specifically withstand the attack of acidic media. Other functional group types of POSS cannot achieve the same technical effect in the harsh acidic environment targeted by this invention.

[0050] In summary, this invention, through the combination of a specific MAPOSS crosslinking system and an optimized reinforcing filler system, synergistically solves the key problems of mechanical property degradation and sealing failure of tetrafluoropropylene rubber (TEBR) under the harsh environments of high temperature, high pressure, and strong corrosion in oil and gas fields. The resulting material exhibits significantly superior overall performance compared to traditional modified fluororubber, providing longer service life and higher reliability for high-temperature and high-pressure sealing components (such as packer sleeves and valve seats) in oil extraction, oil and gas storage and transportation, and other fields, demonstrating significant industrial application value.

Claims

1. A corrosion-resistant tetrafluoroethylene rubber sealing material for harsh environments in oil and gas fields, made from the following raw materials in parts by weight: 100 parts of raw tetrafluoropropylene rubber; 4-10 parts of cage-type silsesquioxane co-crosslinking agent; 1-3 parts of peroxide main crosslinking agent; 30-60 parts of reinforcing filler; Processing aids 2-10 parts; wherein The cage-like silsesquioxane co-crosslinking agent is methacryloyloxypropyl cage-like polysilsesquioxane.

2. The tetrafluoropropylene rubber sealing material according to claim 1, characterized in that: The amount of the cage-type silsesquioxane co-crosslinking agent is 6-8 parts.

3. The tetrafluoropropylene rubber sealing material according to claim 1 or 2, characterized in that: The peroxide main crosslinking agent is dicumyl peroxide.

4. The tetrafluoroethylene rubber sealing material according to any one of claims 1-3, characterized in that: The reinforcing filler is carbon black and / or carbon nanotubes.

5. The tetrafluoropropylene rubber sealing material according to any one of claims 1-4, characterized in that: The processing aids include one or more of surfactants, antioxidants, and plasticizers; preferably, the processing aids include calcium stearate and / or zinc oxide.

6. A method for preparing the corrosion-resistant tetrafluoroethylene rubber sealing material according to any one of claims 1-5, comprising the following steps: S1. Plasticize the raw tetrapropylene fluororubber; S2. Add cage-type silsesquioxane co-crosslinking agent, reinforcing filler and processing aid to the plasticized raw rubber, and mix to obtain compound rubber. S3. Add peroxide main crosslinking agent to the compound, continue to mix evenly and then sheet out; S4. The rubber compound after sheeting is vulcanized to obtain the tetrafluoroethylene rubber sealing material.

7. The preparation method according to claim 6, characterized in that: In step S4, the vulcanization includes a first-stage vulcanization and a second-stage vulcanization; the temperature of the first-stage vulcanization is 160-180℃, the pressure is 10-15MPa, and the vulcanization time is the positive vulcanization time t90 of the compound; the temperature of the second-stage vulcanization is 180-220℃, and the time is 12-24 hours.

8. The application of the corrosion-resistant tetrafluoroethylene rubber sealing material according to any one of claims 1-5 in the preparation of seals for downhole tools in oil and gas fields.

9. The application according to claim 8, characterized in that: The sealing components for oil and gas field downhole tools include packer sleeves, blowout preventer cores, or valve seals.

10. The application according to claim 8 or 9, characterized in that: The application environment is a medium environment containing hydrogen sulfide and / or carbon dioxide; The application environment has a temperature of 150-230℃ and a pressure of 30-120MPa.

Images