High-strength fluororubber and method for producing the same

Abstract

The application relates to the rubber field, in particular to a high-strength fluorine rubber and a preparation method thereof. The fluorine rubber comprises the following components in parts by weight: 100 parts of fluorine rubber raw rubber, 20-30 parts of a reinforcing agent, 10-20 parts of a filler, 7-16 parts of an acid absorber, 0.1-0.5 parts of a coupling agent, 0.1-1 parts of a release agent, 2-5 parts of a vulcanizing agent and 1.2-2 parts of a vulcanization accelerator. The fluorine rubber material prepared by the application not only has the advantages of high-temperature resistance, oil resistance and corrosion resistance, but also has excellent strength and toughness, is suitable for being used as a material for chemical equipment sealing gaskets and liners, can keep stable in various chemical and solvent environments, and ensures long-term normal operation of the equipment.

Description

A high-strength fluororubber and its preparation method Technical Field

[0001] This invention relates to the field of rubber, and more specifically to a high-strength fluororubber and its preparation method. Background Technology

[0002] As oil and gas drilling depths increase, the composition and pressure of oil and gas become more complex. Consequently, higher demands are placed on the rubber sealing materials used in oil and gas drilling, transportation, and processing equipment. Under high-temperature, high-pressure, and highly corrosive conditions, rubber materials, in addition to withstanding complex media, are required to exhibit high hardness, high tensile strength, high shear deformation resistance, explosion resistance or resistance to rapid gas depressurization, and resistance to extrusion deformation.

[0003] Valves are crucial components in oil and gas pipeline transportation. In the non-metallic sealing field of valves, non-metallic materials generally refer to plastics, rubber, and flexible graphite. Rubber, due to its excellent elasticity, significant tolerance compensation, and low requirements for the machining precision of metal parts, is widely used in valve sealing. However, existing rubber materials do not provide ideal sealing performance under high temperature and pressure, especially pressures above 15 MPa and temperatures above 200℃. This is mainly due to poor wear resistance, low hardness, low strength, large resistance to extrusion deformation, and susceptibility to high-pressure shear failure. Furthermore, in high-temperature and high-pressure liquid or gas environments, rubber seals are prone to rapid gas pressure release failure.

[0004] Fluororubber (FKM) is a synthetic polymer elastomer in which fluorine atoms are bonded to the carbon atoms of the main chain or side chains. This polymer material possesses properties such as heat resistance, oil resistance, solvent resistance, corrosion resistance, and resistance to strong oxidants, and exhibits excellent physical and mechanical properties. It is widely used in aerospace, aviation, weaponry, automotive, and petrochemical industries. With the development of science and technology, higher requirements have been placed on the comprehensive performance of fluororubber. Due to its high viscosity, fluororubber is difficult to uniformly mix with small-particle-size inorganic fillers. Currently, most commercially available products use large-particle-size carbon black (such as N990) produced by thermal decomposition for reinforcement. Although the particle size is relatively large (average 280nm), local agglomeration may still occur due to its low structure. Furthermore, the carbon black produced by thermal decomposition significantly increases the hardness and stress of the vulcanized rubber, leading to a decrease in the tensile strength and tear strength of the material, affecting dynamic sealing performance. Therefore, although existing fluororubber materials have advantages in high temperature resistance and corrosion resistance, their relatively low strength limits their application in more fields. Summary of the Invention

[0005] To address the problems existing in the prior art, the purpose of this invention is to provide a high-strength fluororubber and its preparation method.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a high-strength fluororubber, comprising the following components by weight:

[0008] 100 parts fluororubber raw rubber, 20-30 parts reinforcing agent, 10-20 parts filler, 7-16 parts acid absorber, 0.1-0.5 parts coupling agent, 0.1-1 part release agent, 2-5 parts vulcanizing agent and 1.2-2 parts vulcanization accelerator.

[0009] Preferably, the fluororubber raw rubber is at least one of FE2461, FE2462, FE2463, FE2601, and FE2603.

[0010] Preferably, the filler is at least one of silica, calcium carbonate, barium sulfate, calcium oxide, and carbon fiber.

[0011] Preferably, the acid absorbent is a mixture of calcium hydroxide and magnesium oxide, with a mass ratio of calcium hydroxide to magnesium oxide of 3-6:5-10.

[0012] Preferably, the reinforcing agent is modified carbon black N990, and the preparation process is as follows: first, carbon black N990 is subjected to aminated treatment to obtain aminated carbon black N990; then, 5-hydroxymethylfurfural undergoes an amine-aldehyde condensation reaction to obtain Schiff base functionalized carbon black N990; finally, it undergoes an esterification reaction with carboxyl-terminated fluororubber to obtain modified carbon black N990.

[0013] Preferably, the coupling agent is silane coupling agent A-151 or silane coupling agent A-171.

[0014] Preferably, the release agent is carnauba wax, paraffin wax, or polyethylene wax.

[0015] Preferably, the vulcanizing agent is bisphenol AF; the vulcanization accelerator is benzyltriphenylphosphine chloride.

[0016] Preferably, the method for preparing the modified N990 carbon black includes:

[0017] S1. Take carbon black N990 and place it in an aqueous solution of ethanol. Then add an aminosilane coupling agent and disperse it fully. Then reflux the reaction in a water bath for 2-8 hours. After centrifugation and drying, amino-modified carbon black N990 is obtained.

[0018] S2. Dissolve 5-hydroxymethylfurfural (5-HMF) in anhydrous ethanol, then add amino-modified carbon black N990, add catalyst dropwise, heat to 70-80℃ and reflux for 10-20h. After the reaction is completed, remove the solvent under reduced pressure, wash with water 3-5 times and dry to obtain Schiff base functionalized carbon black N990.

[0019] S3. Dissolve carboxyl-terminated fluororubber (CTLF) in tetrahydrofuran, then slowly add Schiff base functionalized carbon black N990 while stirring. After all the carbon black has been added, disperse it thoroughly until uniform. Add p-toluenesulfonic acid as a catalyst. Under nitrogen protection, heat to 110-150℃ and stir for 8-16 hours. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, wash with saturated sodium carbonate solution until neutral, wash with water 3-5 times and dry to obtain modified N990 carbon black.

[0020] Preferably, in S1, the carbon black N990 is obtained by thermal decomposition, with a particle size range of 200-500 nm and an average particle size of 280 nm.

[0021] Preferably, in S1, the mass fraction of the aqueous ethanol solution is 40%-80%.

[0022] Preferably, in S1, the aminosilane coupling agent is at least one of KH-550, KH-602, and KH-792.

[0023] Preferably, in S1, the mass-to-volume ratio of carbon black N990, aminosilane coupling agent, and aqueous ethanol solution is 1g:(0.12-0.38)g:(10-20)mL.

[0024] Preferably, in S2, the mass-to-volume ratio of amino-modified carbon black N990, 5-hydroxymethylfurfural, and anhydrous ethanol is 1 g:(0.26-0.52) g:(10-20) mL.

[0025] Preferably, in S2, the catalyst is glacial acetic acid, and the amount of glacial acetic acid added is 1%-5% of the mass of 5-hydroxymethylfurfural.

[0026] Preferably, in S3, the number average molecular weight of the carboxyl-terminated fluororubber is 2300-2520, and the carboxyl content is 2.1%-2.5%.

[0027] Preferably, in S3, the mass-to-volume ratio of Schiff base functionalized carbon black N990, carboxyl-terminated fluororubber, and tetrahydrofuran is 1g:(1.8-3.6)g:(12-24)mL.

[0028] Preferably, in step S3, the catalyst is p-toluenesulfonic acid, and the amount added is 1.3%-4.6% of the mass of the carboxyl-terminated fluororubber.

[0029] Secondly, the present invention provides a method for preparing high-strength fluororubber, comprising the following steps:

[0030] (1) First, plasticize the raw fluororubber in a two-roll mill, control the distance between two adjacent roll surfaces to be 0.3-0.5 mm, the plasticizing temperature to be 40-60℃, and the plasticizing time to be 10-40 min, to obtain the plasticized fluororubber.

[0031] (2) Add the plasticized fluororubber, acid absorbent, mold release agent, coupling agent, reinforcing agent and filler into the internal mixer, mix thoroughly, the mixing temperature is 55-65℃ and the mixing time is 4-8min, then add vulcanizing agent and vulcanization accelerator, mix again, the mixing temperature is 90-110℃ and the mixing time is 3-5min, to obtain the mixed fluororubber;

[0032] (3) Place the mixed fluororubber in a mold and press it into shape at a temperature of 165-170℃, a pressure of 15-20MPa, and a time of 10-15min. After demolding, treat it in an oven at 200-220℃ for 12-24h to obtain high-strength fluororubber.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. This invention prepares a fluororubber material that not only has the advantages of high temperature resistance, oil resistance, and corrosion resistance, but also exhibits excellent strength and toughness. It is suitable for use as a material for sealing gaskets and linings in chemical equipment, and can remain stable in various chemical and solvent environments, ensuring the long-term normal operation of the equipment.

[0035] 2. In the fluororubber material prepared by the present invention, fillers and reinforcing agents are used in combination. The reinforcing agent is modified carbon black N990. Compared with traditional carbon black N990, the modified carbon black N990 of the present invention has better compatibility with fluororubber and significantly improves the tensile strength and tear strength of fluororubber while maintaining high temperature resistance and corrosion resistance.

[0036] 3. The preparation process of modified carbon black N990 is as follows: first, carbon black N990 is treated with an aminosilane coupling agent to obtain amino-modified carbon black N990; then, it is combined with 5-hydroxymethylfurfural through an amino-aldehyde condensation reaction to obtain functionalized carbon black N990 containing Schiff base; finally, it is esterified with carboxyl-terminated fluororubber to finally prepare carbon black N990 material coated with Schiff base functional groups and fluororubber, i.e., modified carbon black N990.

[0037] 4. The addition of modified N990 carbon black as a reinforcing agent in this invention not only reduces dust pollution, but also shortens the mixing time by 30%-50% (traditional mixing time is 10-20 minutes) during subsequent mixing, thus accelerating the production efficiency of fluororubber in industry. Attached Figure Description

[0038] The present invention will be further described with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative effort.

[0039] Figure 1 is a SEM image (5 μm) of the fluororubber material prepared in Example 1 of this invention;

[0040] Figure 2 is a schematic SEM image (200 μm) of the fluororubber material prepared in Example 1 of this invention. Detailed Implementation

[0041] The technical solution of the present invention is illustrated below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or defining the scope of the present invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0042] To better understand the above technical solutions, exemplary embodiments of the present invention are described in more detail below. While exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the invention to those skilled in the art.

[0043] The present invention will be further described below with reference to the following embodiments.

[0044] Example 1

[0045] A high-strength fluororubber material, comprising the following components by weight:

[0046] 100 parts fluororubber raw rubber, 25 parts reinforcing agent, 15 parts filler, 12 parts acid absorber, 0.3 parts coupling agent, 0.6 parts release agent, 3 parts vulcanizing agent and 1.8 parts vulcanization accelerator.

[0047] The fluororubber raw rubber is graded FE2463; the filler is 5μm calcium carbonate; the acid absorber is a mixture of calcium hydroxide and magnesium oxide in a mass ratio of 4:9; the coupling agent is silane coupling agent A-151; the release agent is carnauba wax; the vulcanizing agent is bisphenol AF; and the vulcanization accelerator is benzyltriphenylphosphine chloride.

[0048] The reinforcing agent is modified N990 carbon black, and its preparation method includes:

[0049] S1. Take 1g of carbon black N990 (average particle size of 280nm) obtained by thermal pyrolysis and place it in 15mL of aqueous solution of 60% ethanol. Then add 0.26g of aminosilane coupling agent KH-550. After fully dispersing, reflux the reaction in a water bath for 6h. After centrifugation and drying, amino-modified carbon black N990 is obtained.

[0050] S2. Dissolve 0.39g of 5-hydroxymethylfurfural (5-HMF) in 15mL of anhydrous ethanol, then add 1g of amino-modified carbon black N990, add 3% by weight of 5-hydroxymethylfurfural in glacial acetic acid, heat to 75℃ and reflux for 15h. After the reaction is completed, remove the solvent under reduced pressure, wash with water 4 times and dry to obtain Schiff base functionalized carbon black N990.

[0051] S3. Dissolve 2.7g of carboxyl-terminated fluororubber (CTLF, Mn=2460, carboxyl percentage 2.3%) in 18mL of tetrahydrofuran. Then, while stirring, slowly add 1g of Schiff base functionalized carbon black N990. After all the carbon black has been added, disperse it thoroughly until uniform. Add 2.7% by weight of p-toluenesulfonic acid as a catalyst. Under nitrogen protection, heat to 130℃ and stir for 12h. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, wash with saturated sodium carbonate solution until neutral, wash with water 4 times and dry. After pulverization, obtain modified N990 carbon black.

[0052] The preparation method of the above-mentioned high-strength fluororubber includes the following steps:

[0053] (1) First, the raw fluororubber is plasticized in a two-roll mill. The distance between two adjacent roll surfaces is controlled to be 0.5 mm, the plasticizing temperature is 50℃, and the plasticizing time is 25 min to obtain the plasticized fluororubber.

[0054] (2) Add the plasticized fluororubber, acid absorbent, mold release agent, coupling agent, reinforcing agent and filler into the internal mixer, mix thoroughly, the mixing temperature is 60℃ and the mixing time is 6min, then add vulcanizing agent and vulcanization accelerator, mix again, the mixing temperature is 100℃ and the mixing time is 4min to obtain the mixed fluororubber.

[0055] (3) The mixed fluororubber is placed in a mold and pressed at a temperature of 170℃, a pressure of 18MPa, and a time of 12min. After demolding, it is treated in an oven at 210℃ for 18h to obtain high-strength fluororubber.

[0056] Example 2

[0057] A high-strength fluororubber material, comprising the following components by weight:

[0058] 100 parts fluororubber raw rubber, 22 parts reinforcing agent, 13 parts filler, 12 parts acid absorber, 0.4 parts coupling agent, 0.7 parts release agent, 4 parts vulcanizing agent and 1.7 parts vulcanization accelerator.

[0059] The fluororubber raw rubber is grade FE2461; the filler is barium sulfate; the acid absorber is a mixture of calcium hydroxide and magnesium oxide in a mass ratio of 3:5; the coupling agent is silane coupling agent A-171; the mold release agent is paraffin wax; the vulcanizing agent is bisphenol AF; and the vulcanization accelerator is benzyltriphenylphosphine chloride.

[0060] The reinforcing agent is modified N990 carbon black, and its preparation method includes:

[0061] S1. Take 1g of carbon black N990 (average particle size of 280nm) obtained by thermal pyrolysis and place it in 12mL of 50% ethanol aqueous solution. Then add 0.17g of aminosilane coupling agent, and after fully dispersing, reflux the reaction in a water bath for 3h. After centrifugation and drying, amino-modified carbon black N990 is obtained.

[0062] S2. Dissolve (0.26-0.52)g of 5-hydroxymethylfurfural (5-HMF) in (10-20)mL of anhydrous ethanol, then add 1g of amino-modified carbon black N990, add 2% of glacial acetic acid by mass of 5-hydroxymethylfurfural, heat to 75℃ and reflux for 15h. After the reaction is completed, remove the solvent under reduced pressure, wash with water 3 times and dry to obtain Schiff base functionalized carbon black N990.

[0063] S3. Dissolve 2.2g of carboxyl-terminated fluororubber (CTLF, Mn=2460, carboxyl percentage 2.3%) in 20mL of tetrahydrofuran. Then, while stirring, slowly add 1g of Schiff base functionalized carbon black N990. After all the carbon black has been added, disperse it thoroughly until uniform. Add 3.1% by weight of p-toluenesulfonic acid as a catalyst. Under nitrogen protection, heat to 120℃ and stir for 10h. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, wash with saturated sodium carbonate solution until neutral, wash with water 3 times and dry. After pulverization, obtain modified N990 carbon black.

[0064] The preparation method of the above-mentioned high-strength fluororubber includes the following steps:

[0065] (1) First, the raw fluororubber is plasticized in a two-roll mill. The distance between two adjacent roll surfaces is controlled to be 0.5 mm, the plasticizing temperature is 50℃, and the plasticizing time is 25 min to obtain the plasticized fluororubber.

[0066] (2) Add the plasticized fluororubber, acid absorbent, mold release agent, coupling agent, reinforcing agent and filler into the internal mixer, mix thoroughly, the mixing temperature is 60℃ and the mixing time is 6min, then add vulcanizing agent and vulcanization accelerator, mix again, the mixing temperature is 100℃ and the mixing time is 4min to obtain the mixed fluororubber.

[0067] (3) The mixed fluororubber is placed in a mold and pressed at a temperature of 170℃, a pressure of 18MPa, and a time of 12min. After demolding, it is treated in an oven at 210℃ for 18h to obtain high-strength fluororubber.

[0068] Example 3

[0069] A high-strength fluororubber material, comprising the following components by weight:

[0070] 100 parts fluororubber raw rubber, 20 parts reinforcing agent, 10 parts filler, 7 parts acid absorber, 0.1 parts coupling agent, 0.1 parts release agent, 2 parts vulcanizing agent and 1.2 parts vulcanization accelerator.

[0071] The fluororubber raw rubber is grade FE2462; the filler is silica; the acid absorber is a mixture of calcium hydroxide and magnesium oxide in a mass ratio of 6:10; the coupling agent is silane coupling agent A-151; the mold release agent is polyethylene wax; the vulcanizing agent is bisphenol AF; and the vulcanization accelerator is benzyltriphenylphosphine chloride.

[0072] The reinforcing agent is modified N990 carbon black, and its preparation method includes:

[0073] S1. Take 1g of carbon black N990 (average particle size of 280nm) obtained by thermal pyrolysis and place it in (10-20)mL of aqueous solution of 40% ethanol. Then add 0.12g of aminosilane coupling agent, and after fully dispersing, reflux the reaction in a water bath for 2h. After centrifugation and drying, amino-modified carbon black N990 is obtained.

[0074] S2. Dissolve 0.26g of 5-hydroxymethylfurfural (5-HMF) in 10mL of anhydrous ethanol, then add 1g of amino-modified carbon black N990, add 1% of glacial acetic acid by mass of 5-hydroxymethylfurfural, heat to 70℃ and reflux for 10h. After the reaction is completed, remove the solvent under reduced pressure, wash with water 3 times and dry to obtain Schiff base functionalized carbon black N990.

[0075] S3. Dissolve 1.8g of carboxyl-terminated fluororubber (CTLF, Mn=2460, carboxyl percentage 2.3%) in 12mL of tetrahydrofuran. Then, while stirring, slowly add 1g of Schiff base functionalized carbon black N990. After all the carbon black has been added, disperse it thoroughly until uniform. Add 1.3% by weight of p-toluenesulfonic acid as a catalyst. Under nitrogen protection, heat to 110℃ and stir for 16h. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, wash with saturated sodium carbonate solution until neutral, wash with water 3 times and dry. After pulverization, obtain modified N990 carbon black.

[0076] The preparation method of the above-mentioned high-strength fluororubber includes the following steps:

[0077] (1) First, the raw fluororubber is plasticized in a two-roll mill. The distance between two adjacent roll surfaces is controlled to be 0.5 mm, the plasticizing temperature is 40℃, and the plasticizing time is 40 min to obtain the plasticized fluororubber.

[0078] (2) Add the plasticized fluororubber, acid absorbent, mold release agent, coupling agent, reinforcing agent and filler into the internal mixer, mix thoroughly, the mixing temperature is 55℃ and the mixing time is 8min, then add vulcanizing agent and vulcanization accelerator, mix again, the mixing temperature is 90℃ and the mixing time is 5min to obtain the mixed fluororubber.

[0079] (3) The mixed fluororubber is placed in a mold and pressed at a temperature of 165℃, a pressure of 15MPa, and a time of 15min. After demolding, it is treated in a 200℃ oven for 24h to obtain high-strength fluororubber.

[0080] Example 4

[0081] A high-strength fluororubber material, comprising the following components by weight:

[0082] 100 parts fluororubber raw rubber, 30 parts reinforcing agent, 20 parts filler, 16 parts acid absorber, 0.5 parts coupling agent, 1 part release agent, 5 parts vulcanizing agent and 2 parts vulcanization accelerator.

[0083] The fluororubber raw rubber is grade FE2603; the filler is carbon fiber; the acid absorber is a mixture of calcium hydroxide and magnesium oxide in a mass ratio of 3:5; the coupling agent is silane coupling agent A-151; the release agent is carnauba wax; the vulcanizing agent is bisphenol AF; and the vulcanization accelerator is benzyltriphenylphosphine chloride.

[0084] The reinforcing agent is modified N990 carbon black, and its preparation method includes:

[0085] S1. Take 1g of carbon black N990 (average particle size of 280nm) obtained by thermal pyrolysis and place it in 20mL of aqueous solution of 80% ethanol. Then add 0.38g of aminosilane coupling agent, disperse it fully, reflux it in a water bath for 8h, and then centrifuge and dry it to obtain aminoated carbon black N990.

[0086] S2. Dissolve 0.52g of 5-hydroxymethylfurfural (5-HMF) in 20mL of anhydrous ethanol, then add 1g of amino-modified carbon black N990, add 5% by weight of 5-hydroxymethylfurfural in glacial acetic acid, heat to 80℃ and reflux for 20h. After the reaction is completed, remove the solvent under reduced pressure, wash with water 5 times and dry to obtain Schiff base functionalized carbon black N990.

[0087] S3. Dissolve 3.6g of carboxyl-terminated fluororubber (CTLF, Mn=2460, carboxyl percentage 2.3%) in 24mL of tetrahydrofuran. Then, while stirring, slowly add 1g of Schiff base functionalized carbon black N990. After all the carbon black has been added, disperse it thoroughly until uniform. Add 4.6% by weight of p-toluenesulfonic acid as a catalyst. Under nitrogen protection, heat to 150℃ and stir for 8 hours. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, wash with saturated sodium carbonate solution until neutral, wash with water 5 times and dry. After pulverization, obtain modified N990 carbon black.

[0088] The preparation method of the above-mentioned high-strength fluororubber includes the following steps:

[0089] (1) First, the raw fluororubber is plasticized in a two-roll mill. The distance between two adjacent roll surfaces is controlled to be 0.5 mm, the plasticizing temperature is 60℃, and the plasticizing time is 10 min to obtain the plasticized fluororubber.

[0090] (2) Add the plasticized fluororubber, acid absorbent, mold release agent, coupling agent, reinforcing agent and filler into the internal mixer, mix thoroughly, the mixing temperature is 65℃ and the mixing time is 4min, then add vulcanizing agent and vulcanization accelerator, mix again, the mixing temperature is 110℃ and the mixing time is 3min to obtain the mixed fluororubber.

[0091] (3) The mixed fluororubber is placed in a mold and pressed at a temperature of 170℃, a pressure of 20MPa, and a time of 10min. After demolding, it is treated in an oven at 220℃ for 12h to obtain high-strength fluororubber.

[0092] Comparative Example 1

[0093] A fluororubber material, comprising the following components by weight:

[0094] 100 parts fluororubber raw rubber, 25 parts reinforcing agent, 15 parts filler, 12 parts acid absorber, 0.3 parts coupling agent, 0.6 parts release agent, 3 parts vulcanizing agent and 1.8 parts vulcanization accelerator.

[0095] The only difference between this comparative example and Example 1 is that the filler was replaced with N990 carbon black (average particle size of 280 nm).

[0096] Comparative Example 2

[0097] A fluororubber material, comprising the following components by weight:

[0098] 100 parts fluororubber raw rubber, 25 parts reinforcing agent, 15 parts filler, 12 parts acid absorber, 0.3 parts coupling agent, 0.6 parts release agent, 3 parts vulcanizing agent and 1.8 parts vulcanization accelerator.

[0099] The only difference between this comparative example and Example 1 is that the filler is replaced with Schiff base functionalized carbon black N990 (preparation is the same as step S2 of Example 1).

[0100] Comparative Example 3

[0101] A fluororubber material, comprising the following components by weight:

[0102] 100 parts fluororubber raw rubber, 25 parts reinforcing agent, 15 parts filler, 12 parts acid absorber, 0.3 parts coupling agent, 0.6 parts release agent, 3 parts vulcanizing agent and 1.8 parts vulcanization accelerator.

[0103] The only difference between this comparative example and Example 1 is that the filler was replaced with a mixture of N990 carbon black (average particle size of 280 nm) and carboxyl-terminated fluororubber (CTLF, Mn = 2460, carboxyl content 2.3%), with a mass ratio of N990 carbon black to carboxyl-terminated fluororubber of 1:2.7.

[0104] Experimental Example

[0105] To more clearly illustrate the content of this invention, comparative examples 1-3 were set as control examples for the optimal embodiment 1, and multiple properties of the fluororubber materials prepared in embodiment 1 and comparative examples 1-3 were tested. Specifically, tensile strength was tested according to ASTM D412, tear strength according to ASTM D624, hardness according to ASTM D2240, high temperature resistance according to ASTM D573 (performance retention rate after aging at 275℃ for 24h), oil resistance according to ASTM D471 (Great Wall thickened hydraulic oil No. 40, 100℃ for 168h, volume measurement before and after immersion), and acid and alkali resistance according to ISO 1817 (alkali solution: 10wt% sodium hydroxide solution; acid solution: 10wt% sulfuric acid solution; 23℃ for 72h, mass change before and after testing).

[0106] The test results are shown in Table 1:

[0107] Table 1 Performance test results of different fluororubber materials

[0108]

[0109] As can be seen from the results in Table 1, compared with Comparative Example 1, the fluororubber material prepared in Example 1 of this invention exhibits superior tensile strength and tear strength while maintaining excellent oil resistance and corrosion resistance, and also shows some improvement in high-temperature resistance. In summary, this demonstrates that the fluororubber material prepared in Example 1 of this invention not only possesses the advantages of high-temperature resistance, oil resistance, and corrosion resistance, but also exhibits excellent strength and toughness, making it suitable for use as a sealing material in various devices and possessing very broad application prospects.

[0110] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A high-strength fluororubber, characterized in that, The product comprises the following components by weight: 100 parts fluororubber raw rubber, 20-30 parts reinforcing agent, 10-20 parts filler, 7-16 parts acid scavenger, 0.1-0.5 parts coupling agent, 0.1-1 parts release agent, 2-5 parts vulcanizing agent, and 1.2-2 parts vulcanization accelerator; the reinforcing agent is modified carbon black N990, and the preparation process is as follows: first, carbon black N990 is aminated to obtain aminated carbon black N990; then, it undergoes an amine-aldehyde condensation reaction with 5-hydroxymethylfurfural to obtain Schiff base functionalized carbon black N990; finally, it undergoes an esterification reaction with carboxyl-terminated fluororubber to obtain modified carbon black N990.

2. The high-strength fluororubber according to claim 1, characterized in that, The filler is at least one of silica, calcium carbonate, barium sulfate, calcium oxide, and carbon fiber.

3. The high-strength fluororubber according to claim 1, characterized in that, The acid absorbent is a mixture of calcium hydroxide and magnesium oxide, with a mass ratio of calcium hydroxide to magnesium oxide of 3-6:5-10.

4. The high-strength fluororubber according to claim 1, characterized in that, The coupling agent is silane coupling agent A-151 or silane coupling agent A-171; the release agent is carnauba wax, paraffin wax or polyethylene wax.

5. A high-strength fluororubber according to claim 1, characterized in that, The vulcanizing agent is bisphenol AF; the vulcanization accelerator is benzyltriphenylphosphine chloride.

6. The high-strength fluororubber according to claim 1, characterized in that, The preparation method of the modified carbon black N990 includes: S1, placing carbon black N990 in an aqueous solution of ethanol, adding an aminosilane coupling agent, dispersing it fully, refluxing it in a water bath for 2-8 hours, centrifuging and drying it to obtain amino-modified carbon black N990; S2, dissolving 5-hydroxymethylfurfural in anhydrous ethanol, adding amino-modified carbon black N990, adding a catalyst dropwise, heating to 70-80℃ and refluxing for 10-20 hours, after the reaction is completed, reducing pressure, washing and drying to obtain Schiff base functionalized carbon black N990; S3, dissolving carboxyl-terminated fluororubber in tetrahydrofuran, then slowly adding Schiff base functionalized carbon black N990 while stirring, after all the carbon black has been added, dispersing it fully until uniform, adding a catalyst, heating it to 110-150℃ under nitrogen protection, stirring at this temperature for 8-16 hours, removing impurities after the reaction is completed to obtain modified carbon black N990.

7. A high-strength fluororubber according to claim 6, characterized in that, In S1, the mass-to-volume ratio of carbon black N990, aminosilane coupling agent, and aqueous ethanol solution is 1g:(0.12-0.38)g:(10-20)mL.

8. A high-strength fluororubber according to claim 6, characterized in that, In S2, the mass-to-volume ratio of amino-modified carbon black N990, 5-hydroxymethylfurfural, and anhydrous ethanol is 1 g:(0.26-0.52) g:(10-20) mL.

9. A high-strength fluororubber according to claim 6, characterized in that, In S3, the mass-volume ratio of Schiff base functionalized carbon black N990, carboxyl-terminated fluororubber, and tetrahydrofuran is 1g:(1.8-3.6)g:(12-24)mL; the catalyst is p-toluenesulfonic acid, and the amount added is 1.3%-4.6% of the mass of the carboxyl-terminated fluororubber.

10. A method for preparing the high-strength fluororubber according to claim 1, characterized in that, Includes the following steps: (1) First, plasticize the raw fluororubber in a two-roll mill to obtain plasticized fluororubber; (2) Add the plasticized fluororubber, acid absorbent, mold release agent, coupling agent, reinforcing agent and filler into a mixer, mix thoroughly, then add vulcanizing agent and vulcanization accelerator, mix again to obtain mixed fluororubber; (3) Place the mixed fluororubber in a mold and press it into shape, demold it and then treat it in an oven to obtain high-strength fluororubber.

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