A fatigue-resistant perfluororubber composition and preparation method thereof

Abstract

The present invention relates to the technical field of rubber materials, and in particular to a fatigue-resistant perfluororubber composition and a preparation method thereof. In order to enhance the fatigue resistance of the rubber composition, the present invention uses perfluororubber as the main rubber material, and further adds modified carbon black filler, and improves the compatibility of the fluorine element with the fluororubber material by introducing the fluorine element on the surface of the carbon black. On this basis, the present invention also introduces a p-phenylenediamine structure with an antioxidant effect on the surface of the carbon black, thereby avoiding the degradation of the rubber under the action of bending and the breaking of the molecular chain, thereby improving the fatigue resistance of the rubber and extending the service life of the rubber.

Description

Technical Field

[0001] The invention relates to the technical field of rubber materials, in particular to a fatigue-resistant perfluororubber composition and a preparation method thereof. Background Art

[0002] Rubber material is a polymer material with excellent chemical resistance and low temperature resistance. It has been widely used in fields such as aerospace, automobiles, ships, and machinery. However, in the application process of existing rubber materials, rubber materials often have to undergo multiple alternating cyclic stresses. Under the continuous action of external forces, rubber materials will continue to undergo dynamic stretching and compression. The performance and structure of rubber materials will change, causing the mechanical properties of rubber products to decline or even crack, and ultimately leading to damage to rubber products. Therefore, it is necessary to conduct research on this situation to improve the fatigue resistance of rubber materials. Summary of the invention

[0003] The object of the present invention is to provide a fatigue-resistant perfluororubber composition and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0005] S1. Preparation of modified carbon black filler;

[0006] S11. KH-550 and succinic anhydride were mixed, heated to 45-60°C, stirred for reaction for 2-4h, carbon black was added thereto, ultrasonic dispersion was performed for 1-1.5h, 10% deionized water by volume of KH-550 was added, stirring was continued for reaction for 4-8h, the precipitate was separated by centrifugation, the precipitate was washed with deionized water for 2-3 times, and then dried to constant weight to obtain carboxylated carbon black;

[0007] S12. Disperse the carboxylated carbon black in 4-pentyn-1-ol, protect under nitrogen atmosphere, stir and disperse for 1.5-2h, add silver trifluoromethanesulfonate, continue stirring for 10-20min, raise the temperature to 80-110°C, stir and react for 4-8h, centrifuge and separate the precipitate, wash with anhydrous ethanol 2-3 times, and dry to constant weight to obtain alkynyl-modified carbon black;

[0008] S13. Under nitrogen atmosphere protection, 4-azido-2,3,5,6-tetrafluorobenzoic acid was dispersed in chloroform, the temperature was raised to 55-60°C, and the mixture was stirred for 2-4 hours, then alkynyl-modified carbon black was added, and ultrasonic vibration was performed for 8-12 hours, and the precipitate was separated by centrifugation. The precipitate was washed 3-5 times with deionized water at a temperature of 85-100°C, and then dried to constant weight to obtain fluorine-modified carbon black;

[0009] S14. Disperse the fluorine-modified carbon black in ether, ultrasonically disperse for 30-45 minutes, add p-aminodiphenylamine, heat to 35°C, evaporate the ether, continue to heat to 95-105°C, stir and react for 4-8 hours, stop heating, cool to room temperature, add ether again, heat to 30°C, stir and disperse for 1-1.5 hours, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol 3-5 times, and dry to constant weight to obtain a modified carbon black filler;

[0010] S2. The perfluoroether rubber raw rubber is mixed with a plasticizer, put into an internal mixer and mixed for 50-70 seconds, and then a modified carbon black filler, zinc oxide, an acid absorber, and an antioxidant are added. After continuing to mix for 90-120 seconds, a vulcanizing agent is added, and after mixing at 120-130°C with a hammer for 60-80 seconds, the material is discharged, and a mixed rubber is obtained by passing through a roller and a sheet;

[0011] S3. The mixed rubber is heated to 155-165° C. and vulcanized at a pressure of 10-15 MPa for 5-12 minutes to obtain a fatigue-resistant perfluororubber composition.

[0012] Furthermore, in terms of weight, in step S11, the mass ratio of KH-550 to succinic anhydride and carbon black is 10:4-5:(0.05-0.15).

[0013] Furthermore, in terms of weight, in step S12, the mass ratio of the carboxylated carbon black, 4-pentyn-1-ol, and silver trifluoromethanesulfonate is 1:(5-35):(0.02-0.08).

[0014] Furthermore, in step S13, the mass ratio of the 4-azido-2,3,5,6-tetrafluorobenzoic acid to the alkynyl-modified carbon black is (0.5-4):1 in parts by weight.

[0015] Furthermore, in terms of parts by weight, in step S14, the mass ratio of the fluorine-modified carbon black to p-aminodiphenylamine is 1:(0.5-8).

[0016] Furthermore, in step S2, the rubber mixture is composed of 75-85 parts of perfluororubber raw rubber, 15-8 parts of modified carbon black filler, 0.3-0.6 parts of zinc oxide, 0.3-1.2 parts of antioxidant, 0.5-1.5 parts of acid absorber, 0.5-1.2 parts of plasticizer, and 1-2.5 parts of vulcanizing agent, in parts by weight.

[0017] Furthermore, in step S2, the antioxidant is triphenyl phosphate; and the plasticizer is at least one of phthalate and diethyl phthalate.

[0018] Furthermore, in step S2, the acid absorber is at least one of NICC5000 and Kywamag150.

[0019] Furthermore, in step S2, the vulcanizing agent is sulfur.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0021] 1. In order to enhance the fatigue resistance of the rubber composition, the present invention uses perfluororubber as the main rubber material. Compared with conventional rubber, perfluororubber introduces fluorine atoms in its chain segments. Fluorine atoms have strong electronegativity and large FC bond energy, which can well shield the carbon chain of the rubber material, thereby improving the stability of the rubber carbon chain and its fatigue resistance under alternating cyclic stress. The introduction of fluorine elements can further improve the flame retardancy and corrosion resistance of the rubber material, so that the rubber material can be applied to more scenarios;

[0022] 2. In order to enhance the fatigue resistance of the rubber material, the present invention further adds a modified carbon black filler therein. The present invention first performs carboxyl modification on the surface of carbon black, and uses KH550 to react with succinic anhydride to prepare silane with a carboxyl terminal. Then, deionized water and the carbon black material are added. With the participation of water, the silane is hydrolyzed and reacts with the hydroxyl group on the surface of the carbon black, thereby grafting the carboxyl group on the surface of the carbon black;

[0023] Afterwards, the carbon black is dispersed in 4-pentyn-1-ol, and an alkynyl group is introduced on the surface of the carbon black by using an esterification reaction between an alcohol hydroxyl group and a carboxyl group. On this basis, 4-azido-2,3,5,6-tetrafluorobenzoic acid is further used to react, and the reaction between the azido group and the alkynyl group is used to introduce the fluorine element on the surface of the carbon black, thereby improving the surface polarity of the carbon black, thereby increasing the compatibility and dispersibility between the carbon black material and the fluororubber. In addition, the present invention further uses an excess of p-aminodiphenylamine to further treat the carbon black material, and uses the amino group to react with the carboxyl group in 4-azido-2,3,5,6-tetrafluorobenzoic acid, thereby introducing an anti-aging agent on the surface of the carbon black. Compared with general antioxidants, the introduction of p-phenylenediamine structure into the surface of carbon black can effectively avoid the precipitation of antioxidants. When rubber encounters flexural fatigue, the addition of carbon black material can reduce the generation of cracks to a certain extent. Since rubber fatigue will first appear in the part that is subjected to too much alternating stress, the rubber material in this part will undergo multiple flexural deformations, and the carbon chain will be stretched and compressed many times, which is easy to break the chain. In this case, the antioxidant component on the surface of carbon black can effectively capture the free radicals and other components generated by the rubber chain breakage, react with the oxygen in the peroxide, avoid the degradation of rubber and the breakage of molecular chains, thereby improving the fatigue resistance of rubber.

[0024] In addition, the vulcanization system used in the perfluororubber composition prepared by the present invention is ordinary vulcanization. Compared with effective vulcanization and semi-effective vulcanization systems, the rubber product formed by the ordinary vulcanization system has a higher polysulfide bond content than a single sulfur bond. Although the bond energy of the single sulfur bond is higher than that of the polysulfide bond, when multiple flexural deformations occur, the polysulfide bond with lower bond energy is more likely to break, and new active sites and free radicals are formed after breaking, thereby resynthesizing new chemical cross-linking bonds, redistributing the stress in the rubber, reducing the stress concentration in the rubber, and extending the service life of the rubber. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The perfluoroether rubber raw rubber used in the embodiments and comparative examples of the present invention is PFE-131TZ perfluoroether rubber raw rubber produced by 3M Company of the United States; the carbon black used is N220 carbon black;

[0027] Embodiment 1. A method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0028] S1. Preparation of modified carbon black filler;

[0029] S11. By weight, 10 parts of KH-550 and 4 parts of succinic anhydride were mixed, heated to 55°C, stirred for reaction for 3 hours, carbon black was added thereto, ultrasonically dispersed for 1 hour, 10% of the volume of KH-550 in deionized water was added, the reaction was continued with stirring for 4 hours, the precipitate was separated by centrifugation, the precipitate was washed twice with deionized water, and then dried to constant weight to obtain carboxylated carbon black;

[0030] S12. Disperse 1 part of carboxylated carbon black into 5 parts of 4-pentyn-1-ol by weight, protect under nitrogen atmosphere, stir and disperse for 1.5 hours, add 0.05 parts of silver trifluoromethanesulfonate, continue stirring for 15 minutes, heat to 95°C, stir and react for 6 hours, centrifuge and separate the precipitate, wash twice with anhydrous ethanol, and dry to constant weight to obtain alkynyl-modified carbon black;

[0031] S13. By weight, under nitrogen atmosphere, 0.5 parts of 4-azido-2,3,5,6-tetrafluorobenzoic acid were dispersed in chloroform, heated to 55°C, stirred and mixed for 2 hours, and then 1 part of alkynyl-modified carbon black was added. After ultrasonic vibration reaction for 8 hours, the precipitate was separated by centrifugation, and the precipitate was washed 5 times with deionized water at 92°C, and dried to constant weight to obtain fluorine-modified carbon black;

[0032] S14. Disperse 1 part of fluorine-modified carbon black in ether by weight, and after ultrasonic dispersion for 30 minutes, add 0.5 parts of p-aminodiphenylamine, raise the temperature to 35°C, evaporate the ether, continue to raise the temperature to 95°C, stir and react for 4 hours, stop heating, cool to room temperature, add ether again, raise the temperature to 30°C, stir and disperse for 1 hour, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol 5 times, and dry to constant weight to obtain a modified carbon black filler;

[0033] S2. By weight, 75 parts of perfluoroether rubber raw rubber were mixed with 1.2 parts of phthalate, put into an internal mixer and mixed for 70 seconds, then 15 parts of modified carbon black filler, 0.5 parts of zinc oxide, 1 part of NICC5000, and 0.3 parts of triphenyl phosphate were added, and the mixing was continued for 120 seconds, and then 1.75 parts of sulfur were added, and the mixture was mixed at 130 ° C for 80 seconds, and then discharged, and the mixed rubber was obtained by roller and sheeting;

[0034] S3. The mixed rubber is heated to 165° C. and vulcanized at a pressure of 12 MPa for 8 minutes to obtain a fatigue-resistant perfluororubber composition.

[0035] Embodiment 2. A method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0036] Compared with Example 1, this example increases the amount of modified carbon black filler added in step S2;

[0037] S1. Preparation of modified carbon black filler;

[0038] S11. By weight, 10 parts of KH-550 and 4 parts of succinic anhydride were mixed, heated to 55°C, stirred for reaction for 3 hours, carbon black was added thereto, ultrasonically dispersed for 1 hour, 10% of the volume of KH-550 in deionized water was added, the reaction was continued with stirring for 4 hours, the precipitate was separated by centrifugation, the precipitate was washed twice with deionized water, and then dried to constant weight to obtain carboxylated carbon black;

[0039] S12. Disperse 1 part of carboxylated carbon black into 5 parts of 4-pentyn-1-ol by weight, protect under nitrogen atmosphere, stir and disperse for 1.5 hours, add 0.05 parts of silver trifluoromethanesulfonate, continue stirring for 15 minutes, heat to 95°C, stir and react for 6 hours, centrifuge and separate the precipitate, wash twice with anhydrous ethanol, and dry to constant weight to obtain alkynyl-modified carbon black;

[0040] S13. By weight, under nitrogen atmosphere, 0.5 parts of 4-azido-2,3,5,6-tetrafluorobenzoic acid were dispersed in chloroform, heated to 55°C, stirred and mixed for 2 hours, and then 1 part of alkynyl-modified carbon black was added. After ultrasonic vibration reaction for 8 hours, the precipitate was separated by centrifugation, and the precipitate was washed 5 times with deionized water at 92°C, and dried to constant weight to obtain fluorine-modified carbon black;

[0041] S14. Disperse 1 part of fluorine-modified carbon black in ether by weight, and after ultrasonic dispersion for 30 minutes, add 0.5 parts of p-aminodiphenylamine, raise the temperature to 35°C, evaporate the ether, continue to raise the temperature to 95°C, stir and react for 4 hours, stop heating, cool to room temperature, add ether again, raise the temperature to 30°C, stir and disperse for 1 hour, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol 5 times, and dry to constant weight to obtain a modified carbon black filler;

[0042] S2. By weight, 75 parts of perfluoroether rubber raw rubber and 1.2 parts of phthalate were mixed, put into an internal mixer and mixed for 70 seconds, 28 parts of modified carbon black filler, 0.5 parts of zinc oxide, 1 part of NICC5000, and 0.3 parts of triphenyl phosphate were added, and the mixing was continued for 120 seconds, and 1.75 parts of sulfur were added. After mixing at 130 ° C, the hammer was mixed for 80 seconds, and the material was discharged, and the mixed rubber was obtained by roller and sheeting;

[0043] S3. The mixed rubber is heated to 165° C. and vulcanized at a pressure of 12 MPa for 8 minutes to obtain a fatigue-resistant perfluororubber composition.

[0044] Embodiment 3. A method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0045] Compared with Example 1, this example increases the amount of 4-pentyn-1-ol added in step S12;

[0046] S1. Preparation of modified carbon black filler;

[0047] S11. By weight, 10 parts of KH-550 and 4 parts of succinic anhydride were mixed, heated to 55°C, stirred for reaction for 3 hours, carbon black was added thereto, ultrasonically dispersed for 1 hour, 10% of the volume of KH-550 in deionized water was added, the reaction was continued with stirring for 4 hours, the precipitate was separated by centrifugation, the precipitate was washed twice with deionized water, and then dried to constant weight to obtain carboxylated carbon black;

[0048] S12. Disperse 1 part of carboxylated carbon black into 5 parts of 4-pentyn-1-ol by weight, protect under nitrogen atmosphere, stir and disperse for 1.5 hours, add 0.05 parts of silver trifluoromethanesulfonate, continue stirring for 15 minutes, heat to 95°C, stir and react for 6 hours, centrifuge and separate the precipitate, wash twice with anhydrous ethanol, and dry to constant weight to obtain alkynyl-modified carbon black;

[0049] S13. By weight, under nitrogen atmosphere, 0.5 parts of 4-azido-2,3,5,6-tetrafluorobenzoic acid were dispersed in chloroform, heated to 55°C, stirred and mixed for 2 hours, and then 1 part of alkynyl-modified carbon black was added. After ultrasonic vibration reaction for 8 hours, the precipitate was separated by centrifugation, and the precipitate was washed 5 times with deionized water at 92°C, and dried to constant weight to obtain fluorine-modified carbon black;

[0050] S14. Disperse 1 part of fluorine-modified carbon black in ether by weight, and after ultrasonic dispersion for 30 minutes, add 0.5 parts of p-aminodiphenylamine, raise the temperature to 35°C, evaporate the ether, continue to raise the temperature to 95°C, stir and react for 4 hours, stop heating, cool to room temperature, add ether again, raise the temperature to 30°C, stir and disperse for 1 hour, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol 5 times, and dry to constant weight to obtain a modified carbon black filler;

[0051] S2. By weight, 75 parts of perfluoroether rubber raw rubber were mixed with 1.2 parts of phthalate, put into an internal mixer and mixed for 70 seconds, then 15 parts of modified carbon black filler, 0.5 parts of zinc oxide, 1 part of NICC5000, and 0.3 parts of triphenyl phosphate were added, and the mixing was continued for 120 seconds, and then 1.75 parts of sulfur were added, and the mixture was mixed at 130 ° C for 80 seconds, and then discharged, and the mixed rubber was obtained by roller and sheeting;

[0052] S3. The mixed rubber is heated to 165° C. and vulcanized at a pressure of 12 MPa for 8 minutes to obtain a fatigue-resistant perfluororubber composition.

[0053] Embodiment 4. A method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0054] Compared with Example 1, this example increases the amount of 4-azido-2,3,5,6-tetrafluorobenzoic acid added in step S13;

[0055] S1. Preparation of modified carbon black filler;

[0056] S11. By weight, 10 parts of KH-550 and 4 parts of succinic anhydride were mixed, heated to 55°C, stirred for reaction for 3 hours, carbon black was added thereto, ultrasonically dispersed for 1 hour, 10% of the volume of KH-550 in deionized water was added, the reaction was continued with stirring for 4 hours, the precipitate was separated by centrifugation, the precipitate was washed twice with deionized water, and then dried to constant weight to obtain carboxylated carbon black;

[0057] S12. Disperse 1 part of carboxylated carbon black into 5 parts of 4-pentyn-1-ol by weight, protect under nitrogen atmosphere, stir and disperse for 1.5 hours, add 0.05 parts of silver trifluoromethanesulfonate, continue stirring for 15 minutes, heat to 95°C, stir and react for 6 hours, centrifuge and separate the precipitate, wash twice with anhydrous ethanol, and dry to constant weight to obtain alkynyl-modified carbon black;

[0058] S13. According to the weight percentage, under the protection of nitrogen atmosphere, 4 parts of 4-azido-2,3,5,6-tetrafluorobenzoic acid were dispersed in chloroform, the temperature was raised to 55°C, and the mixture was stirred for 2 hours. Then, 1 part of alkynyl-modified carbon black was added, and the mixture was subjected to ultrasonic vibration for 8 hours. The precipitate was separated by centrifugation, and the precipitate was washed 5 times with deionized water at a temperature of 92°C, and then dried to constant weight to obtain fluorine-modified carbon black;

[0059] S14. Disperse 1 part of fluorine-modified carbon black in ether by weight, and after ultrasonic dispersion for 30 minutes, add 0.5 parts of p-aminodiphenylamine, raise the temperature to 35°C, evaporate the ether, continue to raise the temperature to 95°C, stir and react for 4 hours, stop heating, cool to room temperature, add ether again, raise the temperature to 30°C, stir and disperse for 1 hour, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol 5 times, and dry to constant weight to obtain a modified carbon black filler;

[0060] S2. By weight, 75 parts of perfluoroether rubber raw rubber were mixed with 1.2 parts of phthalate, put into an internal mixer and mixed for 70 seconds, then 15 parts of modified carbon black filler, 0.5 parts of zinc oxide, 1 part of NICC5000, and 0.3 parts of triphenyl phosphate were added, and the mixing was continued for 120 seconds, and then 1.75 parts of sulfur were added, and the mixture was mixed at 130 ° C for 80 seconds, and then discharged, and the mixed rubber was obtained by roller and sheeting;

[0061] S3. The mixed rubber is heated to 165° C. and vulcanized at a pressure of 12 MPa for 8 minutes to obtain a fatigue-resistant perfluororubber composition.

[0062] Embodiment 5. A method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0063] Compared with Example 1, this example increases the amount of p-aminodiphenylamine added in step S14;

[0064] S1. Preparation of modified carbon black filler;

[0065] S11. By weight, 10 parts of KH-550 and 4 parts of succinic anhydride were mixed, heated to 55°C, stirred for reaction for 3 hours, carbon black was added thereto, ultrasonically dispersed for 1 hour, 10% of the volume of KH-550 in deionized water was added, the reaction was continued with stirring for 4 hours, the precipitate was separated by centrifugation, the precipitate was washed twice with deionized water, and then dried to constant weight to obtain carboxylated carbon black;

[0066] S12. Disperse 1 part of carboxylated carbon black into 5 parts of 4-pentyn-1-ol by weight, protect under nitrogen atmosphere, stir and disperse for 1.5 hours, add 0.05 parts of silver trifluoromethanesulfonate, continue stirring for 15 minutes, heat to 95°C, stir and react for 6 hours, centrifuge and separate the precipitate, wash twice with anhydrous ethanol, and dry to constant weight to obtain alkynyl-modified carbon black;

[0067] S13. By weight, under nitrogen atmosphere, 0.5 parts of 4-azido-2,3,5,6-tetrafluorobenzoic acid were dispersed in chloroform, heated to 55°C, stirred and mixed for 2 hours, and then 1 part of alkynyl-modified carbon black was added. After ultrasonic vibration reaction for 8 hours, the precipitate was separated by centrifugation, and the precipitate was washed 5 times with deionized water at 92°C, and dried to constant weight to obtain fluorine-modified carbon black;

[0068] S14. Disperse 1 part of fluorine-modified carbon black in ether by weight, and after ultrasonic dispersion for 30 minutes, add 8 parts of p-aminodiphenylamine, raise the temperature to 35°C, evaporate the ether, continue to raise the temperature to 95°C, stir and react for 4 hours, stop heating, cool to room temperature, add ether again, raise the temperature to 30°C, stir and disperse for 1 hour, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol 5 times, and dry to constant weight to obtain a modified carbon black filler;

[0069] S2. By weight, 75 parts of perfluoroether rubber raw rubber were mixed with 1.2 parts of phthalate, put into an internal mixer and mixed for 70 seconds, then 15 parts of modified carbon black filler, 0.5 parts of zinc oxide, 1 part of NICC5000, and 0.3 parts of triphenyl phosphate were added, and the mixing was continued for 120 seconds, and then 1.75 parts of sulfur were added, and the mixture was mixed at 130 ° C for 80 seconds, and then discharged, and the mixed rubber was obtained by roller and sheeting;

[0070] S3. The mixed rubber is heated to 165° C. and vulcanized at a pressure of 12 MPa for 8 minutes to obtain a fatigue-resistant perfluororubber composition.

[0071] Comparative Example 1. A method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0072] Compared with Example 1, the carbon black was not modified in this comparative example;

[0073] S1. By weight, 75 parts of perfluoroether rubber raw rubber and 1.2 parts of phthalate were mixed, put into an internal mixer and mixed for 70 seconds, and then 15 parts of carbon black filler, 0.5 parts of zinc oxide, 1 part of NICC5000, and 0.3 parts of triphenyl phosphate were added. After mixing for 120 seconds, 1.75 parts of sulfur were added, and after mixing for 80 seconds at 130 ° C, the material was discharged, and the mixed rubber was obtained by roller and sheeting;

[0074] S2. The mixed rubber is heated to 165° C. and vulcanized at a pressure of 12 MPa for 8 minutes to obtain a fatigue-resistant perfluororubber composition.

[0075] Comparative Example 2. A method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0076] Compared with Example 1, this comparative example does not perform step S14;

[0077] S1. Preparation of modified carbon black filler;

[0078] S11. By weight, 10 parts of KH-550 and 4 parts of succinic anhydride were mixed, heated to 55°C, stirred for reaction for 3 hours, carbon black was added thereto, ultrasonically dispersed for 1 hour, 10% of the volume of KH-550 in deionized water was added, the reaction was continued with stirring for 4 hours, the precipitate was separated by centrifugation, the precipitate was washed twice with deionized water, and then dried to constant weight to obtain carboxylated carbon black;

[0079] S12. Disperse 1 part of carboxylated carbon black into 5 parts of 4-pentyn-1-ol by weight, protect under nitrogen atmosphere, stir and disperse for 1.5 hours, add 0.05 parts of silver trifluoromethanesulfonate, continue stirring for 15 minutes, heat to 95°C, stir and react for 6 hours, centrifuge and separate the precipitate, wash twice with anhydrous ethanol, and dry to constant weight to obtain alkynyl-modified carbon black;

[0080] S13. By weight, under nitrogen atmosphere, 0.5 parts of 4-azido-2,3,5,6-tetrafluorobenzoic acid were dispersed in chloroform, heated to 55°C, stirred and mixed for 2 hours, and then 1 part of alkynyl-modified carbon black was added. After ultrasonic vibration reaction for 8 hours, the precipitate was separated by centrifugation, and the precipitate was washed 5 times with deionized water at 92°C, and dried to constant weight to obtain a modified carbon black filler;

[0081] S2. By weight, 75 parts of perfluoroether rubber raw rubber were mixed with 1.2 parts of phthalate, put into an internal mixer and mixed for 70 seconds, then 15 parts of modified carbon black filler, 0.5 parts of zinc oxide, 1 part of NICC5000, and 0.3 parts of triphenyl phosphate were added, and the mixing was continued for 120 seconds, and then 1.75 parts of sulfur were added, and the mixture was mixed at 130 ° C for 80 seconds, and then discharged, and the mixed rubber was obtained by roller and sheeting;

[0082] S3. The mixed rubber is heated to 165° C. and vulcanized at a pressure of 12 MPa for 8 minutes to obtain a fatigue-resistant perfluororubber composition.

[0083] Comparative Example 3. A method for preparing a fatigue-resistant perfluororubber composition, comprising the following steps:

[0084] Compared with Example 1, the vulcanizing agent used in this comparative example is TMTD;

[0085] S1. Preparation of modified carbon black filler;

[0086] S11. By weight, 10 parts of KH-550 and 4 parts of succinic anhydride were mixed, heated to 55°C, stirred for reaction for 3 hours, carbon black was added thereto, ultrasonically dispersed for 1 hour, 10% of the volume of KH-550 in deionized water was added, the reaction was continued with stirring for 4 hours, the precipitate was separated by centrifugation, the precipitate was washed twice with deionized water, and then dried to constant weight to obtain carboxylated carbon black;

[0087] S12. Disperse 1 part of carboxylated carbon black into 5 parts of 4-pentyn-1-ol by weight, protect under nitrogen atmosphere, stir and disperse for 1.5 hours, add 0.05 parts of silver trifluoromethanesulfonate, continue stirring for 15 minutes, heat to 95°C, stir and react for 6 hours, centrifuge and separate the precipitate, wash twice with anhydrous ethanol, and dry to constant weight to obtain alkynyl-modified carbon black;

[0088] S13. By weight, under nitrogen atmosphere, 0.5 parts of 4-azido-2,3,5,6-tetrafluorobenzoic acid were dispersed in chloroform, heated to 55°C, stirred and mixed for 2 hours, and then 1 part of alkynyl-modified carbon black was added. After ultrasonic vibration reaction for 8 hours, the precipitate was separated by centrifugation, and the precipitate was washed 5 times with deionized water at 92°C, and dried to constant weight to obtain fluorine-modified carbon black;

[0089] S14. Disperse 1 part of fluorine-modified carbon black in ether by weight, and after ultrasonic dispersion for 30 minutes, add 0.5 parts of p-aminodiphenylamine, raise the temperature to 35°C, evaporate the ether, continue to raise the temperature to 95°C, stir and react for 4 hours, stop heating, cool to room temperature, add ether again, raise the temperature to 30°C, stir and disperse for 1 hour, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol 5 times, and dry to constant weight to obtain a modified carbon black filler;

[0090] S2. By weight, 75 parts of perfluoroether rubber raw rubber and 1.2 parts of phthalate were mixed, put into an internal mixer and mixed for 70 seconds, 15 parts of modified carbon black filler, 0.5 parts of zinc oxide, 1 part of NICC5000, and 0.3 parts of triphenyl phosphate were added, and the mixing was continued for 120 seconds, and 1.75 parts of TMTD were added. After mixing at 130 ° C, the hammer was mixed for 80 seconds, and the material was discharged, and the mixed rubber was obtained by roller and sheeting;

[0091] S3. The mixed rubber is heated to 165° C. and vulcanized at a pressure of 12 MPa for 8 minutes to obtain a fatigue-resistant perfluororubber composition.

[0092] Testing: According to GB / T 15584-1995, the fatigue-resistant perfluororubber composition samples prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to dynamic fatigue performance testing, with a preload stress of 4900 N, an amplitude of ±3 mm, and a frequency of 3 Hz;

[0093] According to GB / T 528-1998, the tensile strength and elongation at break of the fatigue-resistant perfluororubber composition samples prepared in Examples 1-5 and Comparative Examples 1-3 were tested; the test results are shown in the following table;

[0094] Tensile strength(MPa) Elongation at break (%) Number of failures Example 1 27 541％ 1.97 million times Example 2 32 485％ 2.12 million times Example 3 28 541％ 1.97 million times Example 4 29 546％ 2.01 million times Example 5 27 542％ 2.05 million times Comparative Example 1 23 480％ 1.42 million times Comparative Example 2 27 542％ 1.69 million times Comparative Example 3 28 545％ 1.73 million times

[0095] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a fatigue-resistant perfluororubber composition, characterized in that: The following steps are involved: S1. Preparation of modified carbon black filler; S11. KH-550 and succinic anhydride were mixed, heated to 45-60°C, stirred for reaction for 2-4 hours, carbon black was added thereto, ultrasonic dispersion was performed for 1-1.5 hours, deionized water (10% by volume of KH-550) was added, the reaction was continued with stirring for 4-8 hours, the precipitate was separated by centrifugation, the precipitate was washed with deionized water for 2-3 times, and then dried to constant weight to obtain carboxylated carbon black; S12. Disperse the carboxylated carbon black in 4-pentyn-1-ol, protect under nitrogen atmosphere, stir and disperse for 1.5-2h, add silver trifluoromethanesulfonate, continue stirring for 10-20min, raise the temperature to 80-110°C, stir and react for 4-8h, centrifuge and separate the precipitate, wash with anhydrous ethanol 2-3 times, and dry to constant weight to obtain alkynyl-modified carbon black; S13. Under nitrogen atmosphere, 4-azido-2,3,5,6-tetrafluorobenzoic acid was dispersed in chloroform, heated to 55-60°C, stirred and mixed for 2-4 hours, and then alkynyl-modified carbon black was added. After ultrasonic vibration reaction for 8-12 hours, the precipitate was separated by centrifugation, and the precipitate was washed 3-5 times with deionized water at a temperature of 85-100°C, and dried to constant weight to obtain fluorine-modified carbon black; S14. Disperse the fluorine-modified carbon black in ether, ultrasonically disperse for 30-45 minutes, add p-aminodiphenylamine, heat to 35°C, evaporate the ether, continue to heat to 95-105°C, stir and react for 4-8 hours, stop heating, cool to room temperature, add ether again, heat to 30°C, stir and disperse for 1-1.5 hours, centrifuge and separate the precipitate, wash the precipitate with anhydrous ethanol 3-5 times, and dry to constant weight to obtain a modified carbon black filler; S2. Mix the raw perfluoroether rubber with the plasticizer, put it into an internal mixer and mix it for 50-70 seconds, then add the modified carbon black filler, zinc oxide, acid absorber and antioxidant, continue mixing for 90-120 seconds, add the vulcanizer, mix it at 120-130℃ with a hammer for 60-80 seconds, unload it, and pass it through a roller to obtain a mixed rubber; S3. The mixed rubber is heated to 155-165° C. and vulcanized at a pressure of 10-15 MPa for 5-12 minutes to obtain a fatigue-resistant perfluororubber composition.

2. The method for preparing a fatigue-resistant perfluororubber composition according to claim 1, characterized in that: In terms of weight, in step S11, the mass ratio of KH-550 to succinic anhydride and carbon black is 10:4-5:(0.05-0.15).

3. The method for preparing a fatigue-resistant perfluororubber composition according to claim 1, characterized in that: In terms of weight, in step S12, the mass ratio of the carboxylated carbon black, 4-pentyn-1-ol, and silver trifluoromethanesulfonate is 1:(5-35):(0.02-0.08).

4. The method for preparing a fatigue-resistant perfluororubber composition according to claim 1, characterized in that: In terms of weight, in step S13, the mass ratio of the 4-azido-2,3,5,6-tetrafluorobenzoic acid to the alkynyl-modified carbon black is (0.5-4):

1.

5. The method for preparing a fatigue-resistant perfluororubber composition according to claim 1, characterized in that: In terms of parts by weight, in step S14, the mass ratio of the fluorine-modified carbon black to p-aminodiphenylamine is 1:(0.5-8).

6. The method for preparing a fatigue-resistant perfluororubber composition according to claim 1, characterized in that: In terms of weight, in step S2, the rubber mixture is composed of 75-85 parts of perfluoroether rubber raw rubber, 15-28 parts of modified carbon black filler, 0.3-0.6 parts of zinc oxide, 0.3-1.2 parts of antioxidant, 0.5-1.5 parts of acid absorber, 0.5-1.2 parts of plasticizer, and 1-2.5 parts of vulcanizing agent.

7. The method for preparing a fatigue-resistant perfluororubber composition according to claim 1, characterized in that: In step S2, the antioxidant is triphenyl phosphate; and the plasticizer is at least one of phthalate and diethyl phthalate.

8. The method for preparing a fatigue-resistant perfluororubber composition according to claim 1, characterized in that: In step S2, the vulcanizing agent is sulfur.

9. A fatigue-resistant perfluororubber composition prepared by the preparation method according to any one of claims 1 to 8.