Perfluoroether rubber-based sealing material and preparation method thereof

Abstract

The invention relates to a sealing material based on perfluoroether rubber and a preparation method thereof, and belongs to the technical field of rubber sealing. The material provided by the invention is prepared from the following components in parts by weight: 100 parts of perfluoroether raw rubber, 10-30 parts of a negative thermal expansion material, 0.3-3.96 parts of a coupling agent, 20-45 parts of a filling agent and 1.0-1.8 parts of a cross-linking agent, the coupling agent accounts for 3-18% of the mass of the negative thermal expansion material; a specific negative thermal expansion material, a coupling agent, a cross-linking agent and the like are selected. The sealing material based on the perfluoroether rubber provided by the invention has excellent high temperature resistance and relatively good mechanical properties, the volume expansion rate of a perfluoroether rubber sealing element at a high temperature is remarkably reduced, the tensile strength is high, the compression set is low, and the sealing material has a very high application value.

Description

Technical Field

[0001] The invention relates to the technical field of rubber sealing, and in particular to a sealing material based on perfluoroether rubber and a preparation method thereof. Background Art

[0002] As the temperature increases, the volume of perfluoroelastomers usually increases, a phenomenon known as thermal expansion. The volume expansion rate of perfluoroelastomers is affected by many factors. Studies have shown that perfluoroelastomers will expand, soften or degrade at high temperatures, which will affect their sealing performance and overall integrity. Negative thermal expansion materials are a class of materials that shrink in volume when the temperature increases. The introduction of this type of material can effectively reduce the volume expansion rate of perfluoroelastomers when the temperature increases.

[0003] At present, in order to improve the sealing performance and tolerance of perfluoroether rubber materials, certain processing aids are usually added to the formula, such as cerium oxide with a particle size of less than or equal to 300nm, peroxide crosslinking agents, such as 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, etc., so as to improve the high temperature resistance of perfluoroether rubber and solve the problems of uneven surface, poor thermal oxidation aging performance and poor thermal stability of rubber products obtained after vulcanization of domestic perfluoroether rubber raw rubber. Although the high temperature tolerance of perfluoroether rubber products has been improved, when applied to the field of seals, excessive volume expansion rate will still cause sealing failure when heated at high temperatures. Chinese patent CN202310844028.2 discloses a high temperature resistant perfluoroether rubber composition, its preparation method and application. The sealing product prepared by using the high temperature resistant perfluoroether rubber composition has a smooth surface, will not affect the etching process during use, and has improved thermal oxidation aging performance, but has low tensile strength. At present, when perfluoroether rubber seals are used in specific applications, at operating temperatures above 300°C, the high-temperature heated sealing products have excessive volume expansion rate and poor overall tensile performance, which leads to frequent sealing failures.

[0004] In order to better improve the sealing and safety of the perfluoroether rubber sealing industry, it is urgent to make technical improvements to the formula and process of perfluoroether rubber materials without affecting the mechanical properties of sealing products, so as to provide a high-performance sealing material with excellent mechanical properties and improved volume expansion rate at high temperature. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a sealing material based on perfluoroether rubber and a preparation method thereof. The material provided by the present invention can improve the mechanical properties and better reduce the volume expansion at high temperature, thereby improving the sealing effect of the perfluoroether rubber material.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a sealing material based on perfluoroether rubber, wherein the raw materials for preparing the sealing material based on perfluoroether rubber include the following components in parts by weight: 100 parts of perfluoroether raw rubber, 10-30 parts of negative thermal expansion material, 0.3-3.96 parts of coupling agent, 20-45 parts of filler, and 1.0-1.8 parts of cross-linking agent;

[0008] The coupling agent accounts for 3-18% of the mass of the negative thermal expansion material;

[0009] The perfluoroether rubber includes perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene; the crosslinking agent is a nitrile vulcanizing agent; the negative thermal expansion material is lithium aluminum silicate, β-ZrW 2 O 8 , ZrW 2 O 4 , ZrV 2 O 7 At least one of the following; the coupling agent is a titanate coupling agent.

[0010] The present invention provides a sealing material based on perfluoroether rubber prepared from specific raw materials. In the perfluoroether raw rubber used in the present invention, the nitrile vulcanization point monomer is perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene, which is vulcanized by reacting with a defined nitrile vulcanizing agent to form a separate benzoxazole aromatic ring, and the maximum use temperature is generally above 300°C. During the application process, the problem of excessive high-temperature volume expansion rate is prone to occur.

[0011] In order to further optimize the performance of perfluoroether rubber sealing materials, give them good mechanical properties, effectively hinder the volume expansion of perfluoroether rubber-based sealing materials at high temperatures, and comprehensively improve the sealing effect of sealing materials, specific types and proportions of negative thermal expansion materials and coupling agents have been introduced. The above-mentioned negative thermal expansion materials have unique crystal structure characteristics. When the temperature rises, the arrangement of molecules will cause the overall volume to decrease and the thermal expansion coefficient to be negative. When heated, they will shrink instead, effectively offsetting the positive thermal expansion effect of other materials.

[0012] The negative thermal expansion material defined in the present invention first reacts and modifies with a coupling agent during the preparation process, and then reacts with the monomer in the perfluoroether rubber to construct a bridge with a specific coupling agent as an intermediate: the molecular chains of the negative thermal expansion material and the perfluoroether rubber are respectively covalently bonded and physically entangled with the two ends of the molecular chain of the coupling agent intermediate. Under a specific ratio of negative thermal expansion material to coupling agent, the high-temperature shrinkage performance of the negative thermal expansion material reduces the volume change of the perfluoroether rubber material, and improves its sealing reliability and stability under extreme high temperature conditions; on the other hand, due to the polarity effect, there is physical entanglement between the molecular chains of the negative thermal expansion material and the perfluoroether rubber, which has good interface compatibility, helps the sealing material maintain better shape stability in a high temperature environment, significantly improves mechanical properties, enhances its tensile strength, and improves the comprehensive performance of the sealing material at extreme temperatures; but when the ratio is too high or too low, it may lead to a deterioration in the comprehensive performance.

[0013] In addition, the present invention also defines a suitable weight ratio of filler and cross-linker, regulates the comprehensive performance of the sealing material based on perfluoroether rubber, regulates the relationship between the mechanical properties and high temperature stability of the material, and achieves a comprehensive and optimal material sealing effect. When the ratio of filler and cross-linker is not appropriate, the mechanical properties and high temperature stability cannot be comprehensively achieved.

[0014] The specific perfluoroether rubber-based sealing material provided by the present invention has very excellent mechanical properties and has the effects of reducing the volume expansion rate at high temperature and improving high temperature tolerance. It is of great value to the research and development promotion of perfluoroether rubber sealing materials in the fields of aerospace, automobile industry, etc.

[0015] Preferably, the filler is carbon black.

[0016] More preferably, the filler is at least one of N990, N774 and spray carbon black.

[0017] As a preferred embodiment of the present invention, the filler is spray carbon black.

[0018] Under appropriate proportions, the present invention preferably uses a specific carbon black material as a filler, which can further improve the mechanical properties and extremely high temperature heat resistance of the material and reduce the volume expansion rate of the material at high temperatures.

[0019] Preferably, the cross-linking agent is diaminobisphenol AF;

[0020] And / or the negative thermal expansion material is ZrV 2 O 7 ;

[0021] And / or the coupling agent is at least one of JS201 and JS102.

[0022] Preferably, after the surface of the negative thermal expansion material is modified by a coupling agent, the surface hydrophilicity and adhesion of the negative thermal expansion material can be significantly improved, and the performance of the sealing material based on perfluoroether rubber of the present invention can be further improved.

[0023] Preferably, the coupling agent accounts for a percentage of the mass of the negative thermal expansion material of 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or a range between any two of them.

[0024] Preferably, the raw materials for preparing the perfluoroether rubber-based sealing material include the following components in parts by weight: 100 parts of perfluoroether raw rubber, 18-30 parts of negative thermal expansion material, 1.6-3.96 parts of coupling agent, 30-45 parts of filler, and 1.3-1.6 parts of cross-linking agent.

[0025] Preferably, the coupling agent accounts for 9-18% of the mass of the negative thermal expansion material.

[0026] Under the preferred ratio of raw materials for preparation, and the preferred ratio of coupling agent to negative thermal expansion material, the mechanical properties of the material can be greatly improved, the heat resistance of the material at extremely high temperatures can be improved, and the high-temperature volume expansion rate can be greatly reduced, with the best overall effect.

[0027] In a second aspect, the present invention provides a method for preparing the above-mentioned perfluoroether rubber-based sealing material, comprising the following steps:

[0028] (1) ultrasonically dispersing and mixing a negative thermal expansion material and a coupling agent in a solvent, reacting the mixture, and then removing the solvent to obtain a modified negative thermal expansion material;

[0029] (2) preheating the mixing mill, adjusting the roller distance to 0.4-0.6 mm, adding the perfluoroether rubber, and after the perfluoroether rubber is wrapped around the roller, adding the modified negative thermal expansion material and the filler;

[0030] (3) adjusting the roller distance to 0.05-0.2 mm, adding a crosslinking agent, rolling and triangular wrapping for 4-6 times, and then calendering a sheet to obtain a perfluoroether rubber compound;

[0031] (4) The perfluoroether rubber compound is vulcanized by a two-stage vulcanization process to obtain the perfluoroether rubber-based sealing material.

[0032] As a preferred embodiment of the present invention, the step (1) is specifically: adding anhydrous ethanol to the negative thermal expansion material, stirring for 30-50 minutes, ultrasonic treatment for 15-20 minutes, adding a coupling agent, repeating the above stirring and ultrasonic treatment, and then removing the solvent to obtain the modified negative thermal expansion material.

[0033] The above modification operation of the negative thermal expansion material by using a coupling agent can, on the one hand, improve the dispersibility of the negative thermal expansion material in the rubber matrix; on the other hand, due to the polar effect, there is physical entanglement between the negative thermal expansion material and the perfluoroether rubber molecular chain, which has good interface compatibility and helps the rubber material maintain better shape stability in a high temperature environment.

[0034] Preferably, in step (1), removing the solvent comprises: removing the supernatant by centrifugation, and drying, wherein the drying temperature is 80-120° C., and the drying time is 12-24 hours.

[0035] Preferably, in the step (4), the obtained perfluoroether rubber mixture is placed for 10-14 hours and then subjected to a two-stage vulcanization process.

[0036] Preferably, in step (4), the two-stage vulcanization process is specifically:

[0037] The first stage of vulcanization: compression vulcanization at a temperature of 160-180°C and a pressure of 10-30MPa for 25-35 minutes;

[0038] The second stage of vulcanization: vulcanization at a temperature of 280-290°C for 12-24 hours.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention provides a sealing material based on perfluoroether rubber. By selecting specific negative thermal expansion materials, coupling agents, fillers and cross-linking agents and exploring their appropriate ratios, the sealing material's tolerance at extremely high temperatures is comprehensively regulated, excellent mechanical properties and high temperature resistance are taken into account, and the volume expansion at high temperatures is significantly reduced, so as to meet the current different applications of perfluoroether rubber formula materials and solve the problems of poor tensile and mechanical properties, reduced sealing performance, and even sealing failure of existing perfluoroether rubber sealing materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The diagram is a diagram of the negative thermal expansion material modified by a coupling agent in the sealing material based on perfluoroether rubber of the present invention and the interaction mechanism after the modification. DETAILED DESCRIPTION

[0042] In order to better illustrate the purpose, technical scheme and advantages of the present invention, the present invention will be further described below in conjunction with specific examples. The test methods used in the following examples are conventional methods unless otherwise specified; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0043] Example 1

[0044] An embodiment of the sealing material based on perfluoroether rubber of the present invention, the preparation method of the sealing material based on perfluoroether rubber described in this embodiment is:

[0045] (1) Pour 0.3 g of coupling agent JS102 into a glass container, then pour in 50 ml of anhydrous ethanol, and let stand for 3 hours to obtain a diluted coupling agent;

[0046] Preparation of modified negative thermal expansion material: 10g negative thermal expansion material ZrV 2 O 7 60 ml of anhydrous ethanol was added to a container, the container was placed in a magnetic stirrer and stirred for 30 min, ultrasonic treatment was performed using an ultrasonic machine for 15 min, the diluted coupling agent was added, the magnetic stirring and ultrasonic operation were repeated, and finally centrifuged, the supernatant was removed, the precipitate was washed with anhydrous ethanol, and then dried at 80 ° C for 12 h to obtain the modified negative thermal expansion functional material ZrV 2 O 7 .

[0047] (2) Open the open mill and preheat it at 50°C for 5 minutes. Adjust the roller distance of the open mill to 0.5 mm, add 100 g of perfluoroether rubber PFR-2000-R raw rubber, and add the modified negative thermal expansion material ZrV prepared in step (1) to the roller of the perfluoroether rubber coated roller mill. 2 O 7 and 20g spray carbon black.

[0048] (3) After the raw materials added in step (2) are mixed evenly, the roller distance of the open mill is adjusted to the minimum (0.1 mm), 1.1 g of nitrile vulcanizing agent diaminobisphenol AF (BOAP) is added, and the mixture is rolled and triangularly wrapped for 5 times, and then rolled into a sheet to obtain a perfluoroether mixed rubber, which is left to stand for 12 hours.

[0049] (4) vulcanizing the perfluoroether rubber mixture after storage by the following two-stage vulcanization process to obtain the perfluoroether rubber-based sealing material:

[0050] One-stage compression vulcanization: the vulcanization temperature is 170°C, the vulcanization time is 30 minutes, and the vulcanization pressure is 30 MPa.

[0051] Second stage vulcanization: Place the product after the first stage vulcanization in an oven, set the temperature to 290°C, and the second stage vulcanization time is 24 hours.

[0052] In the sealing material based on perfluoroether rubber of this embodiment, the negative thermal expansion material is modified by a coupling agent, and the mechanism of physical adsorption and physical entanglement between the modified negative thermal expansion material and the perfluoroether rubber molecules is as follows: Figure 1 shown.

[0053] Embodiment 2-9

[0054] Examples 2-9 are examples of the sealing material based on perfluoroether rubber of the present invention.

[0055] Among them, the differences between Examples 2-6, Examples 8-9 and Example 1 are that the weight parts of the negative thermal expansion material, and / or coupling agent, and / or filler, and / or cross-linking agent are changed, and / or the mass percentage of different coupling agents in the negative thermal expansion material is adjusted; the difference between Example 7 and Example 1 is that the weight parts of the negative thermal expansion material, coupling agent, filler, and cross-linking agent are changed, the mass percentage of different coupling agents in the negative thermal expansion material is adjusted, and at the same time, the type of filler is replaced with carbon black N990.

[0056] The preparation method of the sealing material based on perfluoroether rubber in Examples 2-9 refers to the preparation method in Example 1.

[0057] The specific weight parts of each component in the preparation raw materials of the sealing material based on perfluoroether rubber in Examples 1-9 are shown in Table 1-1.

[0058] Table 1-1 Weight parts of the components of the preparation raw materials of the sealing material based on perfluoroether rubber in the examples

[0059]

[0060]

[0061] Comparative Example 1

[0062] A perfluoroether rubber sealing material, and its preparation method includes the following steps:

[0063] (1) Turn on the open mill and preheat it at 50 °C for 5 minutes. Adjust the roll gap of the open mill to 0.5 mm, and put 100 g of perfluoroether rubber PFR-2000-R raw rubber. After the perfluoroether rubber wraps around the roll of the open mill, add 20 g of spray carbon black.

[0064] (2) After the raw materials added in step (1) are mixed evenly, adjust the roll gap of the open mill to the minimum (0.1 mm), add 1.1 g of nitrile vulcanizing agent diaminodiphenol AF (BOAP), and roll and triangle wrap 5 times continuously, then calender and sheet out to obtain perfluoroether rubber stock, and let it stand for 12 h.

[0065] (3) Use the following two-stage vulcanization process to vulcanize the perfluoroether rubber stock after standing to obtain the sealing material based on perfluoroether rubber:

[0066] First-stage mold pressing vulcanization: The vulcanization temperature is 170 °C, the vulcanization time is 30 min, and the vulcanization pressure is 30 MPa.

[0067] Second stage vulcanization: Place the product after the first stage vulcanization in an oven, set the temperature to 290°C, and the second stage vulcanization time is 24 hours.

[0068] Comparative Example 2

[0069] A perfluoroether rubber sealing material, the preparation method of which comprises the following steps:

[0070] (1) Open the open mill and preheat it at 50°C for 5 minutes. Adjust the roller distance of the open mill to 0.5 mm, add 100 g of perfluoroether rubber PFR-2000-R raw rubber, and add 10 g of untreated negative thermal expansion material ZrV 2 O 7 , 20g spray carbon black.

[0071] (2) After the raw materials added in step (1) are evenly mixed, the roller distance of the open mill is adjusted to the minimum (0.1 mm), 1.1 g of nitrile vulcanizing agent diaminobisphenol AF (BOAP) is added, and the mixture is rolled and triangularly wrapped for 5 times, and then rolled into a sheet to obtain a perfluoroether mixed rubber, which is then left to stand for 12 hours.

[0072] (3) vulcanizing the perfluoroether rubber mixture after storage by the following two-stage vulcanization process to obtain the perfluoroether rubber-based sealing material:

[0073] One-stage compression vulcanization: the vulcanization temperature is 170°C, the vulcanization time is 30 minutes, and the vulcanization pressure is 30 MPa.

[0074] Second stage vulcanization: Place the product after the first stage vulcanization in an oven, set the temperature to 290°C, and the second stage vulcanization time is 24 hours.

[0075] Comparative Example 3

[0076] The difference between Comparative Example 3 and Comparative Example 2 is that the untreated 10g negative thermal expansion material ZrV added in step (1) is 2 O 7 Replaced with 14 g of layered compound Ca 2 RuO 4 , and instead add 25g of spray carbon black and 1.2g of nitrile vulcanizing agent diaminobisphenol AF (BOAP).

[0077] Comparative Example 4

[0078] A perfluoroether rubber sealing material, the preparation method of which comprises the following steps:

[0079] (1) Pour 1.62 g of coupling agent JS102 into a glass container, then pour in 50 ml of anhydrous ethanol, and let stand for 3 hours to obtain a diluted coupling agent;

[0080] Preparation of modified negative expansion material: In a tank filled with 18g of layered compound Ca 2 RuO 4 60 ml of anhydrous ethanol was added to a container, the container was placed in a magnetic stirrer and stirred for 30 min, ultrasonic treatment was performed using an ultrasonic machine for 15 min, and then the diluted coupling agent was added, and the magnetic stirring and ultrasonic operations were repeated. Finally, centrifugation was performed, the supernatant was removed, and the precipitate was washed with anhydrous ethanol and then dried at 80°C for 12 h to obtain the modified layered compound Ca 2 RuO 4 .

[0081] (2) Open the open mill and preheat it at 50°C for 5 minutes. Adjust the roller distance of the open mill to 0.5 mm, add 100 g of perfluoroether rubber PFR-2000-R raw rubber, and add the modified layered compound Ca prepared in step (1) to the rollers of the perfluoroether rubber roll mill. 2 RuO 4 and 30g spray carbon black.

[0082] (3) After the raw materials added in step (2) are mixed evenly, the roller distance of the open mill is adjusted to the minimum (0.1 mm), 1.3 g of nitrile vulcanizing agent diaminobisphenol AF (BOAP) is added, and the mixture is rolled and triangularly wrapped for 5 times, and then rolled into a sheet to obtain a perfluoroether mixed rubber, which is left for 12 hours.

[0083] (4) vulcanizing the perfluoroether rubber mixture after storage by the following two-stage vulcanization process to obtain the perfluoroether rubber-based sealing material:

[0084] One-stage compression vulcanization: the vulcanization temperature is 170°C, the vulcanization time is 30 minutes, and the vulcanization pressure is 30 MPa.

[0085] Second stage vulcanization: Place the product after the first stage vulcanization in an oven, set the temperature to 290°C, and the second stage vulcanization time is 24 hours.

[0086] Comparative Examples 5-8

[0087] The difference between Comparative Examples 5-8 and Example 1 is that the weight ratio of the negative thermal expansion material, and / or the coupling agent, and / or the filler, and / or the cross-linking agent is changed, and / or the mass percentage of different coupling agents in the negative thermal expansion material is adjusted.

[0088] The preparation method of the perfluoroether rubber sealing material in Comparative Examples 5-8 refers to the preparation method in Example 1.

[0089] The specific weight parts of each component in the raw materials for preparing the perfluoroether rubber sealing material in Comparative Examples 1-8 are shown in Table 1-2.

[0090] Table 1-2 Preparation of perfluoroether rubber sealing materials in comparative examples Components by weight

[0091]

[0092] Effect example

[0093] In order to explore the performance of the perfluoroether rubber-based sealing material provided by the present invention, the sealing materials in the embodiments and comparative examples were tested as follows:

[0094] Tensile strength: Use I-type cutting knife to prepare samples and test the tensile strength in accordance with GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber.

[0095] Thermal performance test: hot air compression permanent deformation measurement (compression rate 25%), according to GB / T7759.1-2015 standard, using type B specimen, method A, aging conditions: place the sample in a thermal aging box at 290°C for 70 hours and then take it out. Three parallel samples are tested each time, and the median value is taken as the final result.

[0096] O-ring volume expansion test: The corresponding rubber volume expansion refers to the percentage of volume expansion of rubber after heating. The specific implementation refers to GB / T 1690 to test the volume expansion rate.

[0097] The results of the above performance tests are shown in Table 2:

[0098] Table 2 Performance results of materials in the examples and comparative examples

[0099] Test items Tensile strength(MPa) Compression set (%) 250℃ Volume expansion rate (%) Example 1 15.6 29 21.6 Example 2 16.1 28 21.1 Example 3 16.8 26 21.6 Example 4 17.4 26 19.4 Example 5 17.7 26 18 Example 6 18 25 17.6 Example 7 16.5 27 21.3 Example 8 15.6 28 21.1 Example 9 15.3 26 19.1 Comparative Example 1 15 29 22 Comparative Example 2 15.6 28 21.1 Comparative Example 3 14.9 29 21.6 Comparative Example 4 15 29 21.3 Comparative Example 5 15.3 28 20.9 Comparative Example 6 16.8 27 19.8 Comparative Example 7 15.2 28 21.8 Comparative Example 8 18.3 32 21.6

[0100] From the test results in Table 2, we can see that:

[0101] In contrast, the perfluoroether rubber-based sealing materials provided by the present invention in Examples 1-9 have better comprehensive mechanical properties and heat resistance, with tensile strengths all above 15 MPa, and reduced compression permanent deformation and volume expansion rate at 250°C. Among them, the strategy in Example 6 can be used to obtain a perfluoroether rubber-based sealing material with the best comprehensive sealing application effect, with a compression permanent deformation of 25% and a volume expansion rate of 17.6%, which is significantly better than the perfluoroether rubber sealing material in the comparative example that is outside the scope specified by the present invention.

[0102] From the comparison between Examples 1-6 and Comparative Examples 1-6, it can be seen that the introduction of the negative thermal expansion material modified by a specific coupling agent ratio into the system has a significant effect on the mechanical properties of the sealing material based on perfluoroether rubber of the present invention and improves the heat resistance. This is because the negative thermal expansion material ZrV 2 O 7After modification with coupling agent JS102, a more uniform stress distribution is formed in the rubber matrix, which reduces the local stress concentration of the material when subjected to stress. It has good interface compatibility with the rubber matrix and forms a stable structure, thereby greatly improving the overall performance.

[0103] From the comparison of Examples 6-9 and Comparative Examples 7 and 8, it can be seen that the amount of the specific nitrile vulcanizing agent, cross-linking agent and filler used in the present invention has a significant effect on the heat resistance and thermal volume expansion coefficient of the perfluoroether rubber-based sealing material, and improves the mechanical properties. Selecting appropriate fillers and cross-linking agents for matching can further improve the sealing performance, making the sealing effect more reliable and reducing the risk of leakage.

[0104] In summary, the present invention selects suitable negative thermal expansion materials, coupling agents, fillers and cross-linking agents, and explores their optimal ratio, thereby comprehensively regulating the tolerance of high mechanical strength perfluoroether rubber sealing materials at extremely high temperatures, taking into account excellent mechanical properties and high temperature resistance, and significantly reducing volume expansion at high temperatures, solving the problems of poor tensile properties and mechanical properties, meeting the current different applications of perfluoroether rubber formula materials, and solving the problems of reduced sealing performance and sealing failure, and has great research and application value.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A sealing material based on perfluoroether rubber, characterized in that: The raw materials for preparing the perfluoroether rubber-based sealing material include the following components in parts by weight: 100 parts of perfluoroether raw rubber, 10-30 parts of negative thermal expansion material, 0.3-3.96 parts of coupling agent, 20-45 parts of filler, and 1.0-1.8 parts of cross-linking agent; The coupling agent accounts for 3-18% of the mass of the negative thermal expansion material; The perfluoroether rubber includes perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene; the cross-linking agent is a nitrile vulcanizing agent; the negative thermal expansion material is at least one of lithium aluminum silicate, β-ZrW2O8, ZrW2O4, and ZrV2O7; and the coupling agent is a titanate coupling agent.

2. The perfluoroether rubber-based sealing material according to claim 1, characterized in that: The filler is carbon black.

3. The perfluoroether rubber-based sealing material according to claim 2, characterized in that: The filler is at least one of N990, N774 and spray carbon black.

4. The perfluoroether rubber-based sealing material according to claim 1, characterized in that: The cross-linking agent is diaminobisphenol AF; and / or the negative thermal expansion material is ZrV2O7; And / or the coupling agent is at least one of JS201 and JS102.

5. The perfluoroether rubber-based sealing material according to claim 1, characterized in that: The raw materials for preparing the perfluoroether rubber-based sealing material include the following components in parts by weight: 100 parts of perfluoroether raw rubber, 18-30 parts of negative thermal expansion material, 1.6-3.96 parts of coupling agent, 30-45 parts of filler, and 1.3-1.6 parts of cross-linking agent.

6. The perfluoroether rubber-based sealing material according to claim 1, characterized in that: The coupling agent accounts for 9-18% of the mass of the negative thermal expansion material.

7. The method for preparing a sealing material based on perfluoroether rubber according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) ultrasonically dispersing and mixing a negative thermal expansion material and a coupling agent in a solvent, reacting the mixture, and then removing the solvent to obtain a modified negative thermal expansion material; (2) preheating the mixing mill, adjusting the roller distance to 0.4-0.6 mm, adding the perfluoroether rubber, and after the perfluoroether rubber is wrapped around the roller, adding the modified negative thermal expansion material and the filler; (3) adjusting the roller distance to 0.05-0.2 mm, adding a crosslinking agent, rolling and triangular wrapping for 4-6 times, and then calendering a sheet to obtain a perfluoroether rubber compound; (4) The perfluoroether rubber compound is vulcanized by a two-stage vulcanization process to obtain the perfluoroether rubber-based sealing material.

8. The method for preparing a sealing material based on perfluoroether rubber according to claim 7, characterized in that: In the step (1), the removal of the solvent includes: centrifugation to remove the supernatant, and drying. The drying temperature is 80-120° C. and the drying time is 12-24 hours.

9. The method for preparing a sealing material based on perfluoroether rubber according to claim 7, characterized in that: In the step (4), the obtained perfluoroether rubber mixture is placed for 10-14 hours and then subjected to a two-stage vulcanization process.

10. The method for preparing a sealing material based on perfluoroether rubber according to claim 7, characterized in that: In the step (4), the two-stage vulcanization process is specifically as follows: The first stage of vulcanization: compression vulcanization at a temperature of 160-180°C and a pressure of 10-30MPa for 25-35 minutes; The second stage of vulcanization: vulcanization at a temperature of 280-290°C for 12-24 hours.

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