A methanol, gasoline and mixture thereof resistant fluoroelastomer material and a method of making the same

Abstract

The application relates to the field of high-performance elastomer materials, and particularly discloses a methanol, gasoline and mixture-resistant fluororubber material and a preparation method thereof. The methanol, gasoline and mixture-resistant fluororubber material contains the following raw materials in parts by weight: fluororubber green rubber 100 parts, active magnesium oxide 3-6 parts, calcium hydroxide 3-8 parts, dispersant 1-3 parts, 4-15 parts of carbon black N990, calcium silicate 15-25 parts, bisphenol AF 1.4-2 parts and BPP 0.4-1 part. The preparation method is as follows: the fluororubber green rubber, bisphenol AF and BPP are mixed in a banbury mixer to obtain premix; the premix is subjected to storage treatment, then the active magnesium oxide, calcium hydroxide, dispersant, calcium silicate and carbon black N990 are added, and two-stage mixing is conducted to obtain a mixed rubber; the mixed rubber is subjected to opening and thinning to obtain a finished product; the methanol resistance, gasoline resistance and low volume swelling rate are good, and the mechanical property retention rate is high.

Description

Technical Field

[0001] This application relates to the field of high-performance elastomer materials, and more specifically, to a fluororubber material resistant to methanol, gasoline and mixtures thereof, and a method for preparing the same. Background Technology

[0002] Fluororubber is a synthetic polymer elastomer containing fluorine atoms on the carbon atoms of the main chain or side chain. The introduction of fluorine atoms endows the rubber with excellent heat resistance, oxidation resistance, oil resistance, corrosion resistance and atmospheric aging resistance. It has been widely used in aerospace, aviation, automotive, petroleum and household appliances, especially as a standard sealing and hose material in automotive fuel systems.

[0003] Rubber seals and hoses come into contact with automotive fuels, including methanol and gasoline. Automobiles often alternate between these fuels. Gasoline is primarily a mixture of non-polar hydrocarbons. Traditional fluororubber, with its inherent oil resistance, can protect seals from the effects of gasoline. However, methanol is a highly polar, small-molecule solvent. Fluororubber is prone to swelling in polar methanol, leading to dimensional deformation of the seals, loss of sealing pressure, and fuel leakage. Furthermore, the small-molecule plasticizers in fluororubber are easily dissolved and extracted by methanol, causing the material to harden and become embrittled. Simultaneously, methanol's effect on fluororubber can reduce the tensile strength and elongation of the seals, increasing the risk of seal breakage and affecting their service life.

[0004] Therefore, how to prepare a fluororubber material with good resistance to methanol and gasoline, and with the advantages of low volume swelling rate and high mechanical property retention rate, for use in the manufacture of seals and hoses for automotive fuel systems, is an urgent problem to be solved. Summary of the Invention

[0005] In order to prepare a fluororubber material with good resistance to methanol and gasoline, and with the advantages of low volume swelling rate and high mechanical property retention rate, for use in the manufacture of seals for automotive fuel systems, this application provides a fluororubber material and preparation method resistant to methanol, gasoline and their mixtures.

[0006] In a first aspect, this application provides a fluororubber material resistant to methanol, gasoline, and mixtures thereof, employing the following technical solution: A fluororubber material resistant to methanol, gasoline, and mixtures thereof, wherein the fluororubber material comprises the following raw materials in parts by weight: 100 parts of fluororubber raw rubber, 3-6 parts of activated magnesium oxide, 3-8 parts of calcium hydroxide, 1-3 parts of dispersant, 4-15 parts of carbon black N990, 15-25 parts of calcium silicate, 1.4-2 parts of bisphenol AF, and 0.4-1 parts of BPP.

[0007] By adopting the above technical solutions, fluororubber raw rubber, as the matrix material, can improve the methanol and gasoline resistance of fluororubber materials due to its high fluorine content. Utilizing active magnesium oxide and calcium hydroxide as acid neutralizers can neutralize the hydrogen fluoride generated during vulcanization, improving the crosslinking density and thermal stability. The addition of dispersants promotes the uniform dispersion of active magnesium oxide, calcium hydroxide, and calcium silicate, avoiding localized performance inconsistencies. The combination of carbon black and calcium silicate, as reinforcing materials, enhances the strength and deformation resistance of fluororubber materials, giving them the advantage of low volume swelling. The addition of bisphenol AF and BPP ensures successful vulcanization, further improving the toughness and corrosion resistance of fluororubber materials. When used in the preparation of sealing materials, this improves the retention rate of high mechanical properties of fluororubber materials and further extends the service life of the prepared sealing materials.

[0008] Preferably, the fluororubber raw rubber is either FKM246 or FKM246G, with a fluorine content ≥69.5%.

[0009] By adopting the above technical solution and limiting the fluorine content, fluorine atoms in the molecular structure form a dense protective network, preventing methanol molecules from penetrating and damaging the rubber. Fluorine atoms are highly electronegative, which facilitates the formation of stable CF bonds. Therefore, they are less prone to swelling and degradation after contact with methanol and gasoline. Furthermore, the molecular chains of fluororubber materials with high fluorine content are more tightly arranged, reducing the channels for methanol molecule penetration. This further prevents methanol from penetrating and migrating inside the fluororubber material, thus preventing the fluororubber material from swelling due to methanol. At the same time, it has the advantages of being resistant to methanol and gasoline, giving the finished fluororubber material the advantages of low volume swelling rate and high mechanical property retention rate.

[0010] Preferably, the specific surface area of ​​the active magnesium oxide is 145-155 m². 2 / g, the average particle size of calcium hydroxide is 6-6.5μm.

[0011] By adopting the above technical solution, the activated magnesium oxide particles not only have a certain alkalinity, but also have a high porosity and a large specific surface area. They can adsorb and neutralize acidic substances such as hydrogen fluoride produced by fluororubber, preventing hydrogen fluoride from damaging the molecular chain structure stability of fluororubber materials and ensuring that fluororubber materials have high structural density. Furthermore, the high specific surface area of ​​activated magnesium oxide can form a dense physical barrier, hindering the penetration of methanol and gasoline molecules. Its surface hydroxyl groups form hydrogen bonds with fluororubber molecular chains, enhancing interfacial bonding and reducing swelling. As a result, the finished fluororubber materials have the advantages of low volume swelling rate and high mechanical property retention rate.

[0012] Calcium hydroxide is matched with the fluororubber matrix to form a uniformly dispersed filled structure, reducing stress concentration points, improving anti-swelling ability, and preventing the penetration of substances such as methanol and gasoline. Furthermore, the alkaline properties of calcium hydroxide can neutralize hydrogen fluoride, thereby further reducing the content of acidic substances inside the structure, ensuring structural density while improving structural strength. As a result, the finished fluororubber material has the advantages of low volume swelling rate and high mechanical property retention rate.

[0013] Calcium hydroxide and magnesium oxide work synergistically to enhance the crosslinking density of fluororubber through ionic and hydrogen bond networks, further blocking the penetration of polar media.

[0014] Preferably, the calcium silicate is a calcium silicate composite material, which is composed of calcium silicate microparticles and graphene microsheets in a mass ratio of 2.5-3.5:1.

[0015] By adopting the above technical solution, calcium silicate microparticles and graphene microsheets are combined. The rigid structure of the calcium silicate microparticles can effectively block methanol and gasoline molecules from penetrating into the fluororubber. Combined with the high surface area and layered structure of the graphene microsheets, a dense physical barrier layer can be formed, further reducing the permeability of methanol and gasoline. By controlling and reducing the swelling rate, the finished fluororubber material has the advantage of low volume swelling rate.

[0016] The combination of calcium silicate microparticles and graphene microsheets allows the hydroxyl groups on the surface of the calcium silicate microparticles to form physical cross-linking points with the fluororubber molecular chains, increasing the cross-linking density and thus improving the mechanical properties of the material. Combined with the specific surface area of ​​the graphene microsheets, this further cross-links with the fluororubber. Furthermore, the thermal conductivity of the graphene microsheets allows for rapid dissipation of heat within the material, ensuring the density of the cross-linked structure while further controlling crack propagation. Graphene and calcium silicate remain stable in methanol and gasoline, are not easily corroded or dissolved, and maintain good resistance even after long-term use, preserving the mechanical properties of the fluororubber material and preventing brittleness or breakage, thus extending the service life of finished fluororubber sealing components.

[0017] Preferably, the active magnesium oxide is an active magnesium oxide composite material, which is prepared by active magnesium oxide particles, titanate coupling agent and zinc dimethacrylate in a mass ratio of 1:0.1-0.16:0.1-0.14.

[0018] By adopting the above technical solution, the active magnesium oxide microparticles not only have a certain alkalinity, but also have a high porosity and a large specific surface area. They can adsorb and neutralize acidic substances such as hydrogen fluoride produced by fluororubber, avoid hydrogen fluoride from damaging the molecular chain structure stability of fluororubber materials, and ensure that fluororubber materials have high structural density. As a result, the finished fluororubber materials have the advantages of low volume swelling rate and high mechanical property retention rate.

[0019] The combination of activated magnesium oxide microparticles, titanate coupling agents, and zinc dimethacrylate utilizes the coupling effect of titanate coupling agents to improve the cross-linking density between activated magnesium oxide and fluororubber. Zinc dimethacrylate, acting as a cross-linking agent, further promotes cross-linking between activated magnesium oxide and rubber molecular chains. Supported by the activated magnesium oxide microparticles, a structurally stable three-dimensional cross-linked network is formed, further improving the methanol solvent resistance and mechanical stability of the finished fluororubber material. Even with prolonged methanol penetration, the volume swelling rate of the material is reduced without excessively affecting the strength and flexibility of the sealing material, thus extending its service life.

[0020] Preferably, the calcium hydroxide is a calcium hydroxide composite material, which is prepared by active calcium hydroxide microparticles, silane coupling agent and cellulose nanofibers in a mass ratio of 1:0.1-0.15:0.05-0.1.

[0021] By adopting the above technical solution, the activated calcium hydroxide microparticles have high activity. The active hydroxide ions on their surface can cross-link with the active sites on the fluororubber molecular chain, increasing the cross-linking density between calcium hydroxide and fluororubber, preventing the penetration of substances such as methanol and gasoline, and controlling the occurrence of swelling problems. Furthermore, as an inorganic filler, calcium hydroxide's high specific surface area can enhance the structural strength of fluororubber, and its alkaline properties can neutralize hydrogen fluoride, thereby further reducing the content of acidic substances inside the structure. This ensures structural density while improving structural strength, resulting in finished fluororubber materials with the advantages of low volume swelling rate and high mechanical property retention.

[0022] Calcium hydroxide microparticles, silane coupling agents, and cellulose nanofibers are combined. Calcium hydroxide microparticles serve as a support, while the silane coupling agent enhances the cross-linking effect between calcium hydroxide and fluororubber. The flexible network bridges of the cellulose nanofibers and their surface hydroxyl groups further cross-link with the fluororubber, forming a three-dimensional bridge network in the finished fluororubber material. This prevents swelling caused by methanol penetration. Furthermore, the cellulose nanofibers possess a certain degree of flexibility, allowing them to resist swelling stress and reduce the swelling rate even if methanol gradually penetrates and causes partial swelling and deformation. The structural density of the three-dimensional network prevents dimensional deformation caused by swelling. Simultaneously, the connection between the cellulose nanofibers and the cross-linking effect of the silane coupling agent further ensures the stability of the strength and elongation of the fluororubber material, thus giving it the advantage of high mechanical property retention.

[0023] Secondly, this application provides a method for preparing a fluororubber material resistant to methanol, gasoline, and mixtures thereof, using the following technical solution: A method for preparing a fluororubber material resistant to methanol, gasoline, and mixtures thereof, comprising the following steps: S1. Fluororubber raw rubber, bisphenol AF, and BPP are mixed in an internal mixer to obtain a premix; S2. The premixed material is left to stand, and then active magnesium oxide, calcium hydroxide, dispersant, calcium silicate and carbon black N990 are added. After two stages of mixing, the compound is obtained. S3. After the compounded rubber is rolled into thin sheets, the finished product is obtained.

[0024] By adopting the above technical solution, the prepared fluororubber material is resistant to methanol and gasoline corrosion, and has the advantages of low volume swelling rate and high mechanical property retention rate. It is used to prepare seals for automotive fuel systems and has a long service life.

[0025] Preferably, the specific steps of S1 are as follows: Fluororubber raw rubber, bisphenol AF, and BPP are added to an internal mixer at an initial temperature of 40-60℃. The mixture is discharged when the temperature reaches 90-100℃, completing the first stage of mixing to obtain premixed rubber.

[0026] By adopting the above technical solution, premature plasticization of fluororubber raw rubber can be avoided at a temperature of 40-60℃, ensuring uniform dispersion of the vulcanizing agent and laying the foundation for subsequent crosslinking reactions. The discharge temperature is higher than the initial temperature but lower than the viscous flow temperature, which can ensure the vulcanizing agent reacts fully and avoid excessive oxidation of the rubber compound, thereby maintaining the integrity of the molecular chain. Bisphenol AF is used as the main vulcanizing agent and BPP is used as the accelerator. The combination of the two can form a stable crosslinking structure, which can improve the compression set, chemical resistance and thermal stability of fluororubber. The crosslinking structure can effectively restrict the movement of rubber molecular chains, reduce solvent penetration, thereby reducing the volume swelling rate and maintaining high mechanical properties.

[0027] Preferably, the specific steps of S2 are as follows: After being left to stand, active magnesium oxide, calcium hydroxide, dispersant, calcium silicate and carbon black N990 are added to the internal mixer for a second stage of mixing. The mixture is discharged at 90-100℃ to obtain the compound.

[0028] By adopting the above technical solution, the subsequent addition of raw materials such as active magnesium oxide in the internal mixer can not only improve the strength and corrosion resistance of the finished fluororubber, but also crosslink to form a high-density network, thereby further reducing the volume swelling rate.

[0029] Preferably, during the open mill thinning and sheeting process, the rubber compound passes through the rollers 8-10 times on the open mill, and the temperature of the open mill is 20-60℃.

[0030] By adopting the above technical solutions, the risk of scorching of fluororubber due to high temperature can be avoided at 20-60℃, while maintaining the plasticity of the rubber compound. Ten roll pressings can ensure uniform mixing and dispersion of raw materials, avoiding local over-processing. Multiple roll pressings help relax the molecular chains of fluororubber, improving the self-adhesion and flowability of the rubber compound.

[0031] In summary, this application has the following beneficial effects: 1. Fluororubber raw rubber, as a matrix material, utilizes its high fluorine content to improve the methanol and gasoline resistance of fluororubber materials. Using active magnesium oxide and calcium hydroxide as acid neutralizers, it can neutralize the hydrogen fluoride generated during vulcanization, improving the crosslinking density and thermal stability. The addition of dispersants promotes the uniform dispersion of active magnesium oxide, calcium hydroxide, and calcium silicate, avoiding localized performance inconsistencies. The combination of carbon black and calcium silicate, as reinforcing materials, enhances the strength and deformation resistance of fluororubber materials, resulting in a low volume swelling rate. The addition of bisphenol A (AF) and BPP ensures successful vulcanization, further improving the toughness and corrosion resistance of fluororubber materials. When used in the preparation of sealing materials, it can improve the retention rate of high mechanical properties of fluororubber materials, further extending the service life of the prepared sealing materials.

[0032] 2. Calcium silicate microparticles and graphene microsheets form a multi-scale barrier network in the fluororubber matrix. Calcium silicate fills the microscopic voids, while graphene covers the macroscopic surface, together reducing the permeability of methanol and gasoline. Calcium silicate improves the rigidity and strength of the material through physical cross-linking, while graphene enhances the tensile and tear resistance of the material through its high modulus. The two work together to achieve a high mechanical property retention rate. The chemical inertness of calcium silicate and graphene jointly improves the stability of the material in methanol and gasoline, reducing the performance degradation caused by chemical corrosion. As a result, the finished fluororubber material has the advantages of low volume swelling rate and high mechanical property retention rate.

[0033] 3. Calcium hydroxide and magnesium oxide work synergistically to enhance the crosslinking density of fluororubber through ionic and hydrogen bond networks, further blocking the penetration of polar media. Detailed Implementation

[0034] The present application will be further described in detail below with reference to the embodiments.

[0035] Preparation example of active magnesium oxide composite material All of the following ingredients are commercially available.

[0036] Preparation Example 1: Activated magnesium oxide composite material was prepared using the following method: 0.13 kg of titanate coupling agent was uniformly sprayed onto the surface of 1 kg of active magnesium oxide particles, and then 0.12 kg of zinc dimethacrylate was added and mixed evenly. The average particle size of the active magnesium oxide particles was 2 μm, and the average particle size of the zinc dimethacrylate was 200 nm. After drying and dispersing, an active magnesium oxide composite material was obtained, with an average particle size of less than 3 μm.

[0037] Preparation Example 2: The difference between this preparation example and Preparation Example 1 is that: 0.1 kg of titanate coupling agent was uniformly sprayed onto the surface of 1 kg of active magnesium oxide particles, and then 0.1 kg of zinc dimethacrylate was added and mixed evenly. The average particle size of the active magnesium oxide particles was 2 μm and the average particle size of the zinc dimethacrylate was 200 nm, thus obtaining an active magnesium oxide composite material.

[0038] Preparation Example 3: The difference between this preparation example and Preparation Example 1 is that: 0.16 kg of titanate coupling agent was uniformly sprayed onto the surface of 1 kg of active magnesium oxide particles, and then 0.14 g of zinc dimethacrylate was added and mixed evenly. The average particle size of the active magnesium oxide particles was 2 μm, and the average particle size of the zinc dimethacrylate was 200 nm, thus obtaining an active magnesium oxide composite material.

[0039] Preparation example of calcium hydroxide composite material All of the following ingredients are commercially available.

[0040] Preparation Example 4: Calcium hydroxide composite material was prepared using the following method: 0.13 kg of silane coupling agent was uniformly sprayed onto the surface of 1 kg of active calcium hydroxide particles. The average particle size of the active calcium hydroxide particles was 5 μm. The silane coupling agent was KH-550. Then, 0.07 kg of cellulose nanofibers with an average length of 1 μm were added. The mixture was mixed evenly, dried, and dispersed to obtain the finished calcium hydroxide composite material. The average particle size of the calcium hydroxide composite material was less than 8 μm.

[0041] Preparation Example 5: The difference between this preparation example and Preparation Example 4 is that: 0.15 kg of silane coupling agent was uniformly sprayed onto the surface of 1 kg of active calcium hydroxide particles. The average particle size of the active calcium hydroxide particles was 5 μm. The silane coupling agent was KH-550. Then, 0.05 kg of cellulose nanofibers with an average length of 1 μm were added. The mixture was mixed evenly, dried, and dispersed to obtain the finished calcium hydroxide composite material. The average particle size of the calcium hydroxide composite material was less than 8 μm.

[0042] Preparation Example 6: The difference between this preparation example and Preparation Example 4 is that: 0.1 kg of silane coupling agent was uniformly sprayed onto the surface of 1 kg of active calcium hydroxide particles. The average particle size of the active calcium hydroxide particles was 5 μm. The silane coupling agent was KH-550. Then, 0.1 kg of cellulose nanofibers with an average length of 1 μm were added. The mixture was mixed evenly, dried, and dispersed to obtain the finished calcium hydroxide composite material. The average particle size of the calcium hydroxide composite material was less than 8 μm. Example

[0043] All of the following ingredients are commercially available.

[0044] Example 1: A fluororubber material resistant to methanol, gasoline, and mixtures thereof: 100kg of fluororubber raw rubber, 4kg of activated magnesium oxide, 6kg of calcium hydroxide, 2kg of dispersant, 5kg of carbon black N990, 20kg of calcium silicate, 2kg of bisphenol A (AF), and 0.5kg of BPP; the fluororubber raw rubber is FKM246 with a fluorine content ≥69.5%; the activated magnesium oxide has a specific surface area of ​​150m². 2 / g, the average particle size of calcium hydroxide is 6μm; the dispersant is composed of Rheinland 25 and Rheinland 54 in a mass ratio of 1:1; the average particle size of calcium silicate is 15μm; The preparation method is as follows: S1. Add fluororubber raw rubber, bisphenol AF, and BPP to a mixer with an initial temperature of 50℃. Discharge the rubber at 95℃ to complete the first stage of mixing and obtain the premixed rubber. S2. After standing for 24 hours, add active magnesium oxide, calcium hydroxide, dispersant, calcium silicate and carbon black N990 to the internal mixer for two-stage mixing, and discharge the rubber at 95°C to obtain the compound. S3. The rubber compound is passed through the rollers 10 times on the open mill at a temperature of 40°C to complete the open milling and thinning of the rubber compound into a sheet, thus obtaining the finished product.

[0045] Example 2: The difference between this example and Example 1 is that: 100kg of fluororubber raw rubber, 4kg of activated magnesium oxide, 6kg of calcium hydroxide, 2kg of dispersant, 5kg of carbon black N990, 20kg of calcium silicate, 2kg of bisphenol A (AF), and 0.5kg of BPP; the fluororubber raw rubber is FKM246G; the activated magnesium oxide has a specific surface area of ​​150m². 2 / g, the average particle size of calcium hydroxide is 6μm; the dispersant is composed of Rheinland 25 and Rheinland 54 in a mass ratio of 1:1; the average particle size of calcium silicate is 15μm.

[0046] Example 3: The difference between this example and Example 1 is that: 100kg of fluororubber raw rubber, 4kg of activated magnesium oxide, 6kg of calcium hydroxide, 2kg of dispersant, 5kg of carbon black N990, 20kg of calcium silicate, 2kg of bisphenol A (AF), and 0.5kg of BPP; the fluororubber raw rubber is FKM246 with a fluorine content ≥69.5%; the activated magnesium oxide has a specific surface area of ​​150m². 2 / g, the average particle size of calcium hydroxide is 6μm; the dispersant is composed of Rheinland 25 and Rheinland 54 in a mass ratio of 1:1; the calcium silicate is a calcium silicate composite material, which is prepared by uniformly mixing calcium silicate microparticles and graphene microflakes in a mass ratio of 3:1, the average particle size of the calcium silicate microparticles is 15μm, and the average particle size of the graphene microflakes is 10μm; The preparation method is the same as that in Example 1.

[0047] Example 4: The difference between this example and Example 3 is that: 100kg of fluororubber raw rubber, 3kg of activated magnesium oxide, 3kg of calcium hydroxide, 1kg of dispersant, 4kg of carbon black N990, 15kg of calcium silicate, 1.4kg of bisphenol AF, and 0.4kg of BPP; the fluororubber raw rubber is FKM246G; the activated magnesium oxide has a specific surface area of ​​145m². 2 / g, the average particle size of calcium hydroxide is 6μm; the dispersant is composed of Rheinland 25 and Rheinland 54 in a mass ratio of 1:1; the calcium silicate is a calcium silicate composite material, which is prepared by uniformly mixing calcium silicate microparticles and graphene microflakes in a mass ratio of 2.5:1, the average particle size of the calcium silicate microparticles is 10μm, and the average particle size of the graphene microflakes is 8μm; The preparation method is as follows: S1. Add fluororubber raw rubber, bisphenol AF, and BPP to a mixer with an initial temperature of 40℃. Discharge the rubber at 90℃ to complete the first stage of mixing and obtain the premixed rubber. S2. After standing for 24 hours, add active magnesium oxide, calcium hydroxide, dispersant, calcium silicate and carbon black N990 to the internal mixer for two-stage mixing, and discharge the rubber at 90°C to obtain the compound. S3. The rubber compound is passed through the rollers 8 times on the open mill at a temperature of 20°C to complete the open milling and thinning of the rubber compound into sheets, thus obtaining the finished product.

[0048] Example 5: The difference between this example and Example 3 is that: 100kg fluororubber raw rubber, 6kg activated magnesium oxide, 8kg calcium hydroxide, 3kg dispersant, 15kg carbon black N990, 25kg calcium silicate, 2kg bisphenol A (AF), 1kg BPP; the fluororubber raw rubber is FKM246G; the activated magnesium oxide has a specific surface area of ​​155m². 2 / g, the average particle size of calcium hydroxide is 6.5μm; the dispersant is composed of Rheinland 25 and Rheinland 54 in a mass ratio of 1:1; the calcium silicate is a calcium silicate composite material, which is prepared by uniformly mixing calcium silicate microparticles and graphene microflakes in a mass ratio of 3.5:1, the average particle size of the calcium silicate microparticles is 15μm, and the average particle size of the graphene microflakes is 12μm.

[0049] The preparation method is as follows: S1. Add fluororubber raw rubber, bisphenol AF, and BPP to a mixer with an initial temperature of 60℃. Discharge the rubber when the temperature reaches 100℃ to complete the first stage of mixing and obtain the premixed rubber. S2. After standing for 24 hours, add active magnesium oxide, calcium hydroxide, dispersant, calcium silicate and carbon black N990 to the internal mixer for two-stage mixing, and discharge the rubber at 100℃ to obtain the compound. S3. The rubber compound is passed through the rollers 10 times on a two-roll mill at a temperature of 60°C to complete the thinning and sheeting of the rubber compound, thus obtaining the finished product.

[0050] Example 6: The difference between this example and Example 3 is that: The active magnesium oxide used in the raw materials was the active magnesium oxide prepared in Preparation Example 1, and the calcium hydroxide used was the calcium hydroxide composite material prepared in Preparation Example 4.

[0051] Example 7: The difference between this example and Example 6 is that: The active magnesium oxide used in the raw materials was the active magnesium oxide prepared in Preparation Example 2, and the calcium hydroxide used was the calcium hydroxide composite material prepared in Preparation Example 5.

[0052] Example 8: The difference between this example and Example 6 is that: The active magnesium oxide used in the raw materials was the active magnesium oxide prepared in Preparation Example 3, and the calcium hydroxide used was the calcium hydroxide composite material prepared in Preparation Example 6.

[0053] Example 9: The difference between this example and Example 6 is that: Zinc dimethacrylate was not added during the preparation of the active magnesium oxide composite material.

[0054] Example 10: The difference between this example and Example 6 is that: No cellulose nanofibers were added during the preparation of the calcium hydroxide composite material.

[0055] Performance testing 1. Specific gravity test Fluororubber materials were prepared using the methods described in Examples 1-5, and their specific gravity was measured and the data were recorded.

[0056] 2. Viscosity performance testing Fluororubber materials were prepared using the methods described in Examples 1-5, and Mooney viscosity was tested and recorded according to GB / T1232.1.

[0057] 3. Rheological property testing Fluororubber materials were prepared using the methods described in Examples 1-5, and their rheological properties were tested at 170℃ for 20 min according to GB / T1233, and the data were recorded.

[0058] 4. Hardness and tensile strength testing Fluororubber materials were prepared using the methods in Examples 1-6 and 9-10, respectively. After a first-stage vulcanization at 170℃ for 20 min and a second-stage vulcanization at 230℃ for 24 h, the hardness was tested according to GB / T531.1 and the tensile strength was tested according to GB / T528. The data were recorded as the initial physical properties.

[0059] 5. Methanol resistance test Fluororubber materials were prepared using the methods described in Examples 1-6 and 9-10, respectively. The methanol resistance was tested and the data were recorded under the conditions of pure methanol (methanol purity ≥99%) and 23℃*72h, in accordance with GB / T1690.

[0060] 6. Oil resistance test Fluororubber materials were prepared using the methods described in Examples 1-5, respectively. Their fuel resistance was tested under pure gasoline conditions at 23°C for 72 hours, in accordance with GB / T1690. The data were recorded and denoted as fuel resistance C.

[0061] 7. Resistance to testing with mixed methanol and fuel oil Fluororubber materials were prepared using the methods described in Examples 1-5, and the relevant data were tested according to GB / T1690 under the conditions of gasoline:methanol 85:15 and 23℃*72h. The results were denoted as fuel-resistant material I.

[0062] Table 1 Performance Test Table

[0063] Table 2 Performance Test Table

[0064] Based on Examples 1-2 and Table 1, it can be seen that the tensile strength of different fluororubber materials varies. They exhibit good resistance to methanol, gasoline, and both methanol and gasoline corrosion, indicating that the finished fluororubber materials possess good resistance to methanol and gasoline, and have the advantages of low volume swelling rate and high mechanical property retention rate.

[0065] As can be seen from Examples 3 and 4-5 and Table 2, the combination of graphene microsheets and calcium silicate can further improve the specific gravity, tensile strength, and resistance to methanol, gasoline, and methanol and gasoline corrosion of fluororubber materials, thereby giving the finished fluororubber materials the advantages of low volume swelling rate and high mechanical property retention rate.

[0066] Table 3 Performance Test Table

[0067] Combining Examples 3 and 6 with Table 3, it can be seen that, compared with Example 3, the active magnesium oxide composite and calcium hydroxide composite in Example 6 reduced the volume change rate, indicating that the finished fluororubber has better methanol resistance. The TS value in the initial tensile test is greater than that in Example 3, and the 100% M value in the initial tensile test is also greater than that in Example 3. This shows that the combination of active magnesium oxide composite and calcium hydroxide composite gives the finished fluororubber the advantages of high mechanical property retention and good methanol resistance.

[0068] Combining Examples 6 and 9-10 with Table 3, it can be seen that in the preparation process of the active magnesium oxide composite material in Example 9, no zinc dimethacrylate was added. Compared with Example 6, the methanol volume change rate of Example 9 was higher than that of Example 6, the TS value in the initial tensile test was lower than that of Example 6, and the resin content of 100% M in the initial tensile test was lower than that of Example 6. This indicates that zinc dimethacrylate, as a crosslinking agent, further promotes the crosslinking connection between active magnesium oxide and rubber molecular chains. With the support of active magnesium oxide particles, a structurally stable three-dimensional crosslinking network is formed, which further improves the methanol solvent resistance and mechanical stability of the finished fluororubber material.

[0069] In Example 10, no cellulose nanofibers were added during the preparation of the calcium hydroxide composite. Compared to Example 6, Example 10 showed a higher methanol volume change rate, a lower TS value during initial tensile testing, and a lower 100% M resin content during initial tensile testing. This indicates that the flexible network bridges of cellulose nanofibers and the hydroxyl groups on the surface of cellulose nanofibers form a three-dimensional bridge network in the fluororubber material, preventing swelling caused by methanol penetration. Furthermore, cellulose nanofibers possess a certain degree of flexibility, and even if methanol gradually penetrates and causes partial swelling and deformation, the cellulose nanofibers can resist swelling stress and reduce the swelling rate. As a result, the fluororubber material exhibits advantages such as good methanol resistance and high mechanical property retention.

[0070] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A fluororubber material resistant to methanol, gasoline, and mixtures thereof, characterized in that, The fluororubber material comprises the following raw materials in parts by weight: 100 parts of fluororubber raw rubber, 3-6 parts of active magnesium oxide, 3-8 parts of calcium hydroxide, 1-3 parts of dispersant, 4-15 parts of carbon black N990, 15-25 parts of calcium silicate, 1.4-2 parts of bisphenol AF, and 0.4-1 parts of BPP.

2. The fluororubber material resistant to methanol, gasoline, and mixtures thereof according to claim 1, characterized in that: The fluororubber raw rubber is either FKM246 or FKM246G, with a fluorine content ≥69.5%.

3. The fluororubber material resistant to methanol, gasoline, and mixtures thereof according to claim 1, characterized in that, The specific surface area of ​​the active magnesium oxide is 145-155 m². 2 / g, the average particle size of calcium hydroxide is 6-6.5μm.

4. A fluororubber material resistant to methanol, gasoline, and mixtures thereof according to claim 1, characterized in that, The calcium silicate is a calcium silicate composite material, which is composed of calcium silicate microparticles and graphene microsheets in a mass ratio of 2.5-3.5:

1.

5. A fluororubber material resistant to methanol, gasoline, and mixtures thereof according to claim 1, characterized in that, The active magnesium oxide is an active magnesium oxide composite material, which is prepared by active magnesium oxide particles, titanate coupling agent and zinc dimethacrylate in a mass ratio of 1:0.1-0.16:0.1-0.

14.

6. A fluororubber material resistant to methanol, gasoline, and mixtures thereof according to claim 5, characterized in that, The calcium hydroxide is a calcium hydroxide composite material, which is made from active calcium hydroxide microparticles, silane coupling agent and cellulose nanofibers in a mass ratio of 1:0.1-0.15:0.05-0.

1.

7. A method for preparing a fluororubber material resistant to methanol, gasoline, and mixtures thereof as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Fluororubber raw rubber, bisphenol AF, and BPP are mixed in an internal mixer to obtain a premix; S2. The premixed material is left to stand, and then active magnesium oxide, calcium hydroxide, dispersant, calcium silicate and carbon black N990 are added. After two stages of mixing, the compound is obtained. S3. After the compounded rubber is rolled into thin sheets, the finished product is obtained.

8. The method for preparing a fluororubber material resistant to methanol, gasoline, and mixtures thereof according to claim 7, characterized in that, The specific steps of S1 are as follows: Fluororubber raw rubber, bisphenol AF, and BPP are added to an internal mixer at an initial temperature of 40-60℃. The mixture is discharged when the temperature reaches 90-100℃, completing the first stage of mixing to obtain premixed rubber.

9. The method for preparing a fluororubber material resistant to methanol, gasoline, and mixtures thereof according to claim 7, characterized in that, The specific steps of S2 are as follows: After being left to stand, active magnesium oxide, calcium hydroxide, dispersant, calcium silicate and carbon black N990 are added to the internal mixer for a second stage of mixing. The mixture is discharged at 90-100℃ to obtain the compound.

10. The method for preparing a fluororubber material resistant to methanol, gasoline, and mixtures thereof according to claim 7, characterized in that, During the open mill thinning and sheeting process, the rubber compound passes through the rollers 8-10 times on the open mill, and the temperature of the open mill is 20-60℃.

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