CN114806046A - Wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber and preparation method thereof - Google Patents
Wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber and preparation method thereof Download PDFInfo
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Abstract
The invention belongs to the field of novel rubber materials, relates to a preparation technology of rubber dynamic sealing materials, and particularly relates to wide-temperature-range low-friction heat-tearing-resistant meta-fluoroether rubber and a preparation method thereof.
Description
Technical Field
The invention belongs to the field of novel rubber materials, and particularly relates to wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber and a preparation method thereof.
Background
Along with the continuous improvement of vehicle performance, the sealing environment of each part of the vehicle is more and more severe, particularly, the requirements on the dynamic sealing of a vibration damping part are more severe, the sealing working condition is that the sealing material reciprocates in an oil medium at minus 40 ℃ to 200 ℃, the sealing pressure is 40Mpa at most, and the sealing material has no leakage, so that the sealing material is required to have the performances of oil resistance, high and low temperature resistance (minus 45 ℃ to 200 ℃), low friction, tearing resistance and the like, but the existing material is difficult to meet the severe requirements.
CN 201510396542.X, a low friction fluororubber material, wherein a rubber material is made to have low friction by adding fluoroether oil having excellent high temperature lubricity and a wear-resistant auxiliary such as carbon fiber and polytetrafluoroethylene to the fluororubber material. Although the wear-resistant performance of the fluororubber is improved, the added wear-resistant auxiliary agent has poor compatibility with the fluororubber, so that the mechanical property and the hot tearing property of the fluororubber are reduced, and the low-temperature performance of the fluororubber is higher than-28 ℃, so that the sealing requirement cannot be met.
CN 201611204398.6, a perfluoroether rubber material for a high-temperature and high-pressure resistant sealing element, a preparation method and an application thereof, wherein perfluoroether rubber is selected, a peroxide vulcanization system is adopted, and the high-temperature and high-pressure resistant performance of the material is improved by adding carbon nano tubes, acid acceptors, processing aids, high-wear-resistant carbon black 550, semi-reinforcing carbon black 774, light carbon black 325 and the like. Although the comprehensive mechanical property and the high-temperature and high-pressure property of the fluoroether rubber are improved, the wear resistance of the fluoroether rubber is not improved, and the wear resistance of the fluoroether rubber can not meet the requirements of the prior art on the functions.
CN 201810736543.8, a graphene modified fluoroether rubber, which is mainly added with graphene and fibrous micro-nano oxide material composite filler to improve the strength, wear resistance and thermal conductivity of the rubber. The invention improves the wear resistance and the heat conductivity of the fluoroether rubber, but the low temperature resistance and the hot tearing resistance of the rubber material are not improved, and the requirements of the prior art on the functions can not be met.
Therefore, how to obtain the wide-temperature-range low-friction heat-tearing-resistant meta-fluoroether rubber with better performance becomes one of the problems to be solved in the field.
Disclosure of Invention
The invention provides a wide-temperature-range low-friction heat-tearing-resistant meta-fluoroether rubber and a preparation method thereof, aiming at the blank of the prior art, the adopted raw materials are a meta-fluoroether rubber-peroxide vulcanization system, and the invention also contains nano silicon nitride subjected to surface treatment, graphite wear-resistant heat-conducting filler subjected to oxidation treatment, a heat-tearing-resistant auxiliary agent and high-structure carbon black, improves the fluidity and the heat-tearing property of the meta-fluoroether rubber by utilizing the low melting point and the migration property of the heat-tearing-resistant auxiliary agent, improves the wear resistance and the heat conductivity of the material without reducing the mechanical property of the rubber, realizes that the friction surface of a meta-fluoroether rubber dynamic sealing product is smooth, compact and free of defects, and improves the heat-tearing resistance and the low-friction property of the product.
The inventor finds that the fluorine content of the metafluoroether rubber is more than 63 percent, the metafluoroether rubber has excellent medium resistance, and the molecules of the metafluoroether rubber have better flexibility due to the introduction of ether bonds on the side chains of macromolecules, so that the metafluoroether rubber has excellent low-temperature resistance. The method comprises the steps of selecting the metafluoroether rubber as a matrix, adopting a peroxide vulcanization system, high-structure carbon black and the like for combined use, adding surface-treated wear-resistant heat-conducting fillers such as nano silicon nitride, oxidation-treated graphite and the like, wherein the surface-treated nano silicon nitride, the oxidation-treated graphite and the metafluoroether rubber have good compatibility, and the wear resistance and the heat conductivity of the material are improved without reducing the mechanical property of the rubber; the hot tearing resistance of the material is improved by adding the hot tearing resistance auxiliary agent.
Based on the inventive concept, the specific technical scheme of the invention is as follows:
the wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber comprises the following components in parts by weight:
wherein the meta-fluoroether rubber is one of VPL85540 (Suwei, Italy), Viton GLT (DuPont, USA) or FLT (Zhonghao morning light) or other meta-fluoroether rubbers;
the wear-resistant heat-conducting filler is surface-treated nano silicon nitride or oxidation-treated graphite;
wherein the surface treated nano silicon nitride is prepared by blending nano silicon carbide and a coupling agent containing aminoalkyl or urea propyl silane in a water bath at 100 ℃ for 3 to 4 hours, then drying the mixture for 4 to 6 hours at 80 to 100 ℃, and breaking the mixture into fine-particle powdery nano silicon nitride by adopting a dispersing instrument and the like; the average grain diameter of the adopted raw material nano silicon carbide is less than or equal to 100 nm; the adopted silane coupling agent is selected from UP-900 or UP-906; the mass ratio of the coupling agent to the nano silicon nitride is 1-3%, and the solvent of the coupling agent is ethanol or acetone;
the oxidation treatment graphite is superfine graphite powder which is obtained by oxidation treatment by adopting an oxidant, cleaning and drying, and the granularity of a finished product is less than 100 meshes; the method comprises the following specific steps: the proportion of the oxidant to the graphite is 20 ml-30 ml: 1g, fully oxidizing in a water bath at 100 ℃ for 2-4 h, repeatedly washing with distilled water for more than 8 times, and drying at 80-100 ℃ for 4-6 h; the adopted oxidant is a mixture of 3-5% by mass of potassium permanganate solution and 8-10% by mass of nitric acid solution in a volume ratio of 1: 1.
The anti-hot tearing auxiliary agent is a mixture of a nano-carbon material anti-tearing auxiliary agent MR-30 and the adopted metafluoroether rubber in a mass ratio of 3:2 or a mixture of a multifunctional auxiliary agent LCA with active groups such as carboxyl, hydroxyl and the like on the surface and magnesium oxide in a mass ratio of 1: 1;
the MR-30 and the LCA are both commercial products;
compared with the prior art, the wear-resistant heat-conducting filler and the anti-hot tearing auxiliary agent are selected as the biggest characteristics of the application, and the wear-resistant heat-conducting filler and the anti-hot tearing auxiliary agent have the following functions:
because the silane coupling agent on the surface of the nano silicon nitride and the active group of the oxidized graphite can effectively improve the compatibility of the nano silicon nitride and the oxidized graphite with the metafluoroether rubber, the nano silicon nitride subjected to surface treatment and the oxidized graphite can ensure the excellent comprehensive mechanical property of the rubber material while effectively improving the wear resistance of the metafluoroether rubber, and particularly, the tearing property can not be reduced; meanwhile, the mixture of the MR-30 and the meta-fluoroether rubber, the mixture of the LCA and the magnesium oxide and the fluoroether rubber have good compatibility and mobility, and the heat resistance and the tear resistance of the fluoroether rubber can be effectively improved; compared with the prior art that only a wear-resistant auxiliary agent (only the wear resistance of the fluoroether rubber can be improved simply and the comprehensive mechanical property of the rubber material can be reduced due to poor compatibility) or a tear-resistant auxiliary agent (only the tear resistance of the fluoroether rubber can be improved simply and the improvement range is limited and the problem of poor compatibility exists), the two auxiliary agents are added, so that the wear resistance, the tear resistance and the thermal conductivity of the rubber material are improved greatly while the excellent comprehensive mechanical property of the fluoroether rubber is achieved, and the fluoroether rubber with excellent comprehensive performance and meeting the background requirement can be obtained.
The high-structure carbon black is one or two of carbon black N990 and spray carbon black;
the acid scavenger is selected from one of magnesium oxide or calcium hydroxide;
the vulcanizing agent is peroxide vulcanizing agent, specifically selected from bis 2,5 or DCP;
the auxiliary crosslinking agent is triallyl isocyanurate TAIC.
After the combination is adopted, the nano silicon nitride subjected to surface treatment and the graphite wear-resistant heat-conducting filler subjected to oxidation treatment are added into the metafluoroether rubber, so that a covalent bond or an active group is formed on the surfaces of the silicon nitride and the graphite, the compatibility of the silicon nitride and the graphite is improved, the wear resistance and the heat conductivity of the material are improved while the mechanical property of the rubber is not reduced, and the dynamic seal metafluoroether rubber material with excellent processing technology, mechanical property and wear resistance is obtained. Meanwhile, the low melting point, the compatibility with the fluoroether rubber and the mobility of the anti-hot tearing auxiliary agent are utilized, so that the fluidity, the processing manufacturability and the hot tearing performance of the fluoroether rubber are improved.
The inventor also provides a preparation method of the wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber, which comprises the following specific steps:
firstly plasticating the meta-fluoroether rubber on an open mill, then adding the anti-tearing auxiliary agent into the rubber, and thinly passing the rubber on the open mill after adding; placing the mixture of the rubber and the anti-tearing auxiliary agent into an internal mixer for internal mixing, firstly adding half of the amount of the high-structure carbon black and half of the amount of the wear-resistant heat-conducting filler, carrying out internal mixing for 2-3 minutes, then adding the rest of the carbon black and the rest of the wear-resistant heat-conducting filler for internal mixing for 2-3 minutes, and finally adding an acid acceptor for internal mixing for 3 minutes, wherein the temperature in the whole internal mixing process is controlled to be 50-80 ℃;
after banburying, taking out the mixture, thinly passing the mixture on an open mill for 5-8 times, discharging the mixture, standing for more than 10 hours, adding a vulcanizing agent and an auxiliary crosslinking agent on the open mill after standing, after all the vulcanizing agent and the auxiliary crosslinking agent are added, thinly passing the mixture for 6-10 times, discharging the mixture for more than 24 hours, and vulcanizing the mixture to obtain a dynamic sealing rubber product;
the vulcanization process is divided into two stages of vulcanization: the first stage of vulcanization is carried out by adopting a vacuum plate vulcanizing machine, the vulcanization temperature is 165 ℃, the vulcanization pressure is 10Mpa, and the vulcanization time is 10min, wherein when the thickness of the product is more than 6mm, the vulcanization time is prolonged by 1min when the thickness of the product is increased by 1 mm; and the second-stage vulcanization is carried out by adopting a high-temperature oven, wherein the vulcanization temperature is 200 ℃, and the vulcanization time is 16-24 hours.
In conclusion, the wide-temperature-range low-friction heat-tearing-resistant meta-fluoroether rubber provided by the invention is medium-resistant, high-temperature-resistant and low-temperature-resistant, particularly the brittle temperature is reduced to below minus 45 ℃ from minus 40 ℃, the tear resistance is obviously improved, the brittle temperature is improved to 18MPa from 16MPa, the friction performance is reduced to 0.35 from 0.8, the temperature rise in the friction area is reduced to 60 ℃ from 142 ℃, the low-pressure deformation is realized, the comprehensive performance is excellent, and the wide-temperature-range low-friction heat-tearing-resistant meta-fluoroether rubber is particularly suitable for the technical field of high-pressure reciprocating sealing materials.
Detailed Description
The present invention is further described below in conjunction with examples which will allow those skilled in the art to more fully understand the present invention, but which are not intended to limit the invention in any way.
Example 1
The wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber comprises the following components in parts by weight:
wherein the meta-fluoroether rubber is VPL 85540;
the wear-resistant heat-conducting filler is UP-900 surface-treated nano silicon nitride;
the anti-hot tearing auxiliary agent is a mixture of MR-30 and the meta-fluoroether rubber in a mass ratio of 3: 2;
the high structure carbon black is carbon black N990;
the acid scavenger is calcium hydroxide;
the vulcanizing agent is DCP;
the assistant crosslinking agent is TAIC.
The preparation method of the UP-900 surface treatment nano silicon nitride comprises the following steps:
mixing nano silicon carbide (average particle size is less than or equal to 100nm) with a silane coupling agent UP-900(UP-900, solvent is acetone) accounting for 2% of the mass ratio of the nano silicon nitride, blending in a water bath at 100 ℃ for 3h, drying at 100 ℃ for 4h to remove the solvent, and scattering the mixture into fine particle powder by using a dispersion instrument.
The preparation method of the wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber comprises the following steps:
plasticating the raw metafluoroether rubber by using an open mill, adding an anti-hot-tearing auxiliary agent for thin mixing, adding a rubber and anti-tearing auxiliary agent mixture, half of carbon black and half of nano silicon nitride subjected to surface treatment into an internal mixer, uniformly mixing for 2-3 minutes, adding the rest of carbon black and the rest of nano silicon nitride, uniformly mixing, finally adding an acid-absorbing agent for mixing for 3 minutes, taking out the mixture after mixing, thin-passing the mixture on the open mill for 5-8 times, placing for more than 10 hours, adding a vulcanizing agent and an auxiliary crosslinking agent into the open mill after placing, thin-passing the mixture for 6-10 times, placing for more than 24 hours, and vulcanizing the mixture;
the vulcanization process is as follows:
the first stage vulcanization is carried out by a vacuum plate vulcanizing machine, the vulcanization temperature is 165 ℃, the vulcanization pressure is 10Mpa, and the vulcanization time is 10 min; and the second-stage vulcanization is carried out by adopting a high-temperature oven, wherein the vulcanization temperature is 200 ℃, and the vulcanization time is 16-24 hours.
Through detection, the finally obtained metafluoroether material has the tensile strength of 13.1MPa, the elongation at break of 170 percent, the hardness of 73, the brittleness temperature of-44 ℃, the thermal decomposition temperature of 410 ℃, and the compression set (180 ℃ multiplied by 72 h): 24 percent, the friction coefficient is 0.51, the temperature rise of a friction area is 92 ℃, the tearing strength is 16.8Mpa, the tearing strength at a high temperature of 165 ℃ is 5.9Mpa, and the tearing defect rate of a parting surface of a product is 5.6 percent.
Example 2
The wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber comprises the following components in parts by weight:
wherein the meta-fluoroether rubber is VITON GLT;
the wear-resistant heat-conducting filler is oxidation-treated fine graphite powder (the particle size is less than 100 meshes);
the anti-hot tearing auxiliary agent is a mixture of LCA and magnesium oxide with the mass ratio of 1: 1;
the high-structure carbon black is spray carbon black;
the acid scavenger is calcium hydroxide;
the vulcanizing agent is bis 2, 5;
the auxiliary crosslinking agent is TAIC.
The preparation method of the oxidation treatment fine graphite powder comprises the following steps:
the graphite is oxidized by adopting a mixture of 3 percent potassium permanganate solution and 9 percent nitric acid solution (the volume ratio of the potassium permanganate solution to the nitric acid solution is 1: 1) as an oxidant, and the ratio of the oxidant to the graphite (the particle size is 200 meshes) is 25 ml: 1g, fully oxidizing in a water bath at 100 ℃ for 4 hours, repeatedly washing with distilled water for 10 times, and drying at 100 ℃ for 4 hours to obtain the oxidation-treated graphite.
The preparation method of the wide-temperature-range low-friction heat-tearing-resistant meta-fluoroether rubber is the same as that in example 1, the inventor does not need to repeat the description, and through detection, the finally obtained meta-fluoroether material has the tensile strength of 13.5MPa, the elongation at break of 165%, the hardness of 75, the brittleness of-46 ℃, the thermal decomposition temperature of 416 ℃, and the compression set (180 ℃ multiplied by 72 h): 26 percent, the friction coefficient is 0.38, the temperature rise of a friction area is 61 ℃, the tearing strength is 18.1MPa, the tearing strength at a high temperature of 165 ℃ is 6.7MPa, and the tearing defect rate of a parting surface of a product is 3.8 percent.
Example 3
The wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber comprises the following components in parts by weight:
wherein the meta-fluoroether rubber is VPL 85540;
the wear-resistant heat-conducting filler is UP-906 surface-treated nano silicon nitride;
the anti-hot tearing auxiliary agent is a mixture of MR-30 and the meta-fluoroether rubber in a mass ratio of 3: 2;
the high structure carbon black is carbon black N990;
the acid absorbent is magnesium oxide;
the vulcanizing agent is DCP;
the auxiliary crosslinking agent is TAIC.
The preparation method of the UP-906 surface treatment nano silicon nitride comprises the following steps:
mixing nano silicon carbide (the average particle size is less than or equal to 100nm) with a silane coupling agent UP-906(UP-906, the solvent is acetone) accounting for 3 percent of the mass of the nano silicon nitride, blending in a water bath at 100 ℃ for 4h, drying at 100 ℃ for 4h to remove the solvent, and scattering the mixture into fine particle powder by adopting a dispersion instrument.
The preparation method of the wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber is the same as that in the example 1, the inventor does not need to repeat the description, and through detection, the finally obtained vinylidene fluoride material has the tensile strength of 12.9MPa, the elongation at break of 178%, the hardness of 73, the brittleness temperature of-46 ℃, the thermal decomposition temperature of 412 ℃ and the compression permanent deformation (180 ℃ multiplied by 72 h): 22 percent, the friction coefficient is 0.42, the temperature of a friction area rises by 68 ℃, the tearing strength is 17.7Mpa, the tearing strength at 165 ℃ is 6.4Mpa, and the tearing defect rate of a parting surface of a product is 3.7 percent.
Example 4
The wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber comprises the following components in parts by weight:
wherein the metafluoroether rubber is Viton GLT;
the wear-resistant heat-conducting filler is a mixture of UP-900 surface-treated nano silicon nitride and oxidation-treated fine graphite powder (the particle size is less than 200 meshes) in a weight ratio of 1: 1;
the anti-hot tearing auxiliary agent is a mixture of LCA and magnesium oxide with the mass ratio of 1: 1;
the high-structure carbon black is spray carbon black;
the acid scavenger is calcium hydroxide;
the vulcanizing agent is bis 2, 5;
the auxiliary crosslinking agent is TAIC.
Wherein the preparation method of UP-900 surface treatment nano silicon nitride and the preparation method of oxidation treatment fine graphite powder refer to the records in examples 1 and 2 respectively;
the preparation method of the wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber is the same as that in the example 1, the inventor does not need to describe any further, and through detection, the finally obtained vinylidene fluoride material has the tensile strength of 14.3MPa, the elongation at break of 182 percent, the hardness of 72, the brittleness temperature of-45 ℃, the thermal decomposition temperature of 417 ℃ and the compression permanent deformation (180 ℃ multiplied by 72 h): 23 percent, the friction coefficient is 0.35, the temperature rise of a friction area is 57 ℃, the tearing strength is 18.2Mpa, the tearing strength at a high temperature of 165 ℃ is 6.9Mpa, and the tearing defect rate of a parting surface of a product is 2.8 percent.
Example 5
The wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber comprises the following components in parts by weight:
wherein the meta-fluoroether rubber is VPL 85540;
the wear-resistant heat-conducting filler is a mixture of UP-900 surface-treated nano silicon nitride and UP-906 surface-treated nano silicon nitride in a weight ratio of 1: 1;
the anti-hot tearing auxiliary agent is a mixture of MR-30 and the meta-fluoroether rubber in a mass ratio of 3: 2;
the high structure carbon black is carbon black N990;
the acid scavenger is calcium hydroxide;
the vulcanizing agent is DCP;
the auxiliary crosslinking agent is TAIC.
Wherein, the preparation methods of the UP-900 surface treatment nano silicon nitride and the UP-900 surface treatment nano silicon nitride refer to the records in the embodiments 1 and 3 respectively;
the preparation method of the wide-temperature-range low-friction thermal tearing-resistant vinylidene fluoride rubber is the same as that of the example 1, the inventor does not need to describe any more, and through detection, the finally obtained vinylidene fluoride rubber material has the tensile strength of 14.2MPa, the tensile elongation of 187%, the hardness of 75, the brittleness temperature of-47 ℃, the thermal decomposition temperature of 413 ℃, and the compression set (180 ℃ x 72 h): 23 percent, the friction coefficient is 0.32, the temperature rise of a friction area is 54 ℃, the tearing strength is 17.6Mpa, the tearing strength at a high temperature of 165 ℃ is 6.4Mpa, and the tearing defect rate of a parting surface of a product is 4.7 percent.
Example 6
The wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber comprises the following components in parts by weight:
wherein the metafluoroether rubber is Viton GLT;
the wear-resistant heat-conducting filler is a mixture of UP-906 surface-treated nano silicon nitride and oxidation-treated fine graphite powder (the particle size is less than 200 meshes) in a weight ratio of 1: 1;
the anti-hot tearing auxiliary agent is a mixture of LCA and magnesium oxide with the mass ratio of 1: 1;
the high-structure carbon black is spray carbon black;
the acid absorbent is calcium hydroxide;
the vulcanizing agent is bis 2, 5;
the auxiliary crosslinking agent is TAIC.
Wherein, the preparation method of UP-906 surface treatment nano silicon nitride and the preparation method of oxidation treatment fine graphite powder refer to the records in the embodiments 3 and 2 respectively;
the preparation method of the wide-temperature-range low-friction heat-tearing-resistant metafluoroether rubber is the same as that in example 1, the inventor does not need to repeat the description, and through detection, the finally obtained metafluoroether material has the tensile strength of 14.1MPa, the elongation at break of 190%, the hardness of 71, the brittleness temperature of-49 ℃, the thermal decomposition temperature of 409 ℃, and the compression permanent deformation (180 ℃ multiplied by 72 h): 26 percent, the friction coefficient is 0.34, the temperature rise of a friction area is 58 ℃, the tearing strength is 18.4Mpa, the tearing strength at a high temperature of 165 ℃ is 7.1Mpa, and the tearing defect rate of a parting surface of a product is 2.6 percent.
Comparative example 1
The vinylidene fluoride ether rubber comprises the following components in parts by weight:
wherein the meta-fluoroether rubber is VPL 85540;
the high structure carbon black is N990 carbon black;
the acid scavenger is calcium hydroxide;
the vulcanizing agent is bis 2, 5;
and auxiliary crosslinking agent TAIC.
The preparation method comprises the following steps:
plasticating the raw metafluoroether rubber by using an open mill, putting the raw metafluoroether rubber into an internal mixer, sequentially adding rubber and half of carbon black into the internal mixer, uniformly mixing for 2-3 minutes, adding the rest carbon black, uniformly mixing, finally adding an acid-absorbing agent, mixing for 3 minutes, taking out a mixture after mixing, thinly passing the mixture on the open mill for 5-8 times, placing the mixture for more than 10 hours, adding bis 2,5 and TAIC on the open mill after placing, thinly passing the mixture for 6-10 times, placing the mixture for more than 24 hours, and vulcanizing the mixture;
the vulcanization process is as follows:
the first stage vulcanization is carried out by a vacuum plate vulcanizing machine, the vulcanization temperature is 165 ℃, the vulcanization pressure is 10Mpa, and the vulcanization time is 10 min; and the second-stage vulcanization is carried out by adopting a high-temperature oven, wherein the vulcanization temperature is 200 ℃, and the vulcanization time is 16-24 hours.
Through detection, the finally obtained metafluoroether material has the tensile strength of 12.7MPa, the elongation at break of 173 percent, the hardness of 71, the brittleness temperature of-40 ℃, the thermal decomposition temperature of 408 ℃, and the compression set (180 ℃ multiplied by 72 h): 28 percent, the friction coefficient is 0.82, the temperature rise of a friction area is 142 ℃, the tearing strength is 16.3Mpa, the tearing strength at a high temperature of 165 ℃ is 4.3Mpa, and the tearing defect rate of a parting surface of a product is 13.3 percent.
Compared with the metafluoroether material obtained in the comparative example 1, the metafluoroether materials obtained in the examples 1 to 6 have improved tensile property, brittle temperature and compression set, and the friction coefficient, the temperature rise of the friction area, the normal-temperature and high-temperature tear strength and the tear defect rate are greatly improved.
Comparative example 2
The vinylidene fluoride ether rubber comprises the following components in parts by weight:
wherein the meta-fluoroether rubber is VPL 85540;
the wear-resistant heat-conducting filler is nano silicon nitride;
the high structure carbon black is N990 carbon black;
the acid scavenger is calcium hydroxide;
the vulcanizing agent is bis 2, 5;
and auxiliary crosslinking agent TAIC.
The preparation method comprises the following steps:
plasticating the raw metafluoroether rubber by using an open mill, adding rubber, half of carbon black and nano silicon nitride into an internal mixer in sequence, uniformly mixing for 2-3 minutes, adding the rest of carbon black and the rest of nano silicon nitride, uniformly mixing, finally adding an acid-absorbing agent, mixing for 3 minutes, taking out a mixture after mixing, thinly passing the mixture on the open mill for 10-15 times, and then placing the mixture for more than 10 hours (compared with the embodiment because the unprocessed nano silicon nitride is poor in compatibility with the fluoroether rubber), adding bis (2, 5) and TAIC (TAIC) on the open mill after placing, thinly passing the mixture for 10-15 times, placing the mixture for more than 24 hours, and vulcanizing the mixture;
the vulcanization process is as follows:
the first-stage vulcanization is carried out by adopting a vacuum plate vulcanizing machine, the vulcanization temperature is 165 ℃, the vulcanization pressure is 10Mpa, and the vulcanization time is 10 min; and the secondary vulcanization is carried out by adopting a high-temperature oven, wherein the vulcanization temperature is 200 ℃, and the vulcanization time is 16-24 hours.
Through detection, the finally obtained metafluoroether material has the tensile strength of 10.4MPa, the elongation at break of 127 percent, the hardness of 73, the brittleness temperature of-42 ℃, the thermal decomposition temperature of 407 ℃, and the compression set (180 ℃ multiplied by 72 h): 29 percent, the friction coefficient is 0.67, the temperature rise of a friction area is 121 ℃, the tearing strength is 11Mpa, the tearing strength at a high temperature of 165 ℃ is 3.9Mpa, and the tearing defect rate of a parting surface of a product is 14.6 percent.
Compared with the metafluoroether material obtained in the comparative example 2, the metafluoroether materials obtained in the examples 1, 3 and 5 have greatly improved tensile strength, elongation at break, friction coefficient, temperature rise of friction area, tear strength and tear defect rate.
Comparative example 3
The vinylidene fluoride ether rubber comprises the following components in parts by weight:
wherein the meta-fluoroether rubber is VITON GLT;
the wear-resistant heat-conducting filler is graphite (with 200 meshes);
the high-structure carbon black is spray carbon black;
the acid scavenger is calcium hydroxide;
the vulcanizing agent is bis 2, 5;
TAIC of co-crosslinking agent.
The preparation method comprises the following steps:
plasticating the raw metafluoroether rubber by using an open mill, adding rubber, half of carbon black and graphite in turn into an internal mixer for uniformly mixing for 2-3 minutes, adding the rest of carbon black and the rest of graphite for uniformly mixing, finally adding an acid-absorbing agent for mixing for 3 minutes, taking out a mixture after mixing, carrying out thin passing on the open mill for 10-15 times, carrying out sheet discharging (the sheet discharging is carried out for several times compared with the embodiment because the compatibility of untreated graphite and fluoroether rubber is poor), standing for more than 10 hours, adding bis 2,5 and TAIC on the open mill after standing, carrying out thin passing for 10-15 times, standing for more than 24 hours, and vulcanizing;
the vulcanization process is as follows:
the first stage vulcanization is carried out by a vacuum plate vulcanizing machine, the vulcanization temperature is 165 ℃, the vulcanization pressure is 10Mpa, and the vulcanization time is 10 min; and the second-stage vulcanization is carried out by adopting a high-temperature oven, wherein the vulcanization temperature is 200 ℃, and the vulcanization time is 16-24 hours.
Through detection, the finally obtained metafluoroether material has the tensile strength of 9.8MPa, the elongation at break of 135 percent, the hardness of 74, the brittleness temperature of-45 ℃, the thermal decomposition temperature of 411 ℃, the compression set (180 ℃ multiplied by 72 h): 27 percent, the friction coefficient is 0.60, the temperature rise of a friction area is 92 ℃, the tearing strength is 10.6Mpa, the tearing strength at a high temperature of 165 ℃ is 3.7Mpa, and the tearing defect rate of a parting surface of a product is 15.1 percent.
Compared with the vinylidene fluoride ether material obtained in the comparative example 3, the vinylidene fluoride ether material obtained in the example 2 has greatly improved tensile strength, elongation at break, friction coefficient, temperature rise of a friction area, tearing strength and tearing defect rate.
The foregoing is considered as illustrative of the preferred embodiments of the invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (6)
1. The wide-temperature-range low-friction heat-tearing-resistant vinylidene fluoride rubber is characterized by comprising the following components in parts by weight:
wherein the meta-fluoroether rubber is one of VPL85540 or Viton GLT or FLT or other meta-fluoroether rubbers;
the wear-resistant heat-conducting filler is surface-treated nano silicon nitride or oxidation-treated graphite;
the anti-hot tearing auxiliary agent is a mixture of a nano-carbon material anti-tearing auxiliary agent MR-30 and the adopted metafluoroether rubber in a mass ratio of 3:2 or a mixture of a multifunctional auxiliary agent LCA and magnesium oxide in a mass ratio of 1: 1.
2. The wide temperature range, low friction, heat-tear resistant vinylidene fluoride rubber of claim 1,
the surface treated nano silicon nitride is prepared by blending nano silicon carbide and a coupling agent containing amino alkyl or urea propyl silane in a water bath at 100 ℃ for 3 to 4 hours, then drying the mixture at 80 to 100 ℃ for 4 to 6 hours, and breaking the mixture into fine-particle powdery nano silicon nitride by adopting a dispersing instrument and the like; the average grain diameter of the adopted raw material nano silicon carbide is less than or equal to 100 nm; the adopted silane coupling agent is selected from UP-900 or UP-906; the mass ratio of the coupling agent to the nano silicon nitride is 1-3%, and the solvent of the coupling agent is ethanol or acetone.
3. The wide temperature range, low friction, thermal tear resistant vinylidene fluoride rubber of claim 1,
the oxidation treatment graphite is superfine graphite powder which is obtained by oxidation treatment by adopting an oxidant, cleaning and drying, and the granularity of a finished product is less than 100 meshes; the method comprises the following specific steps: the proportion of the oxidant to the graphite is 20 ml-30 ml: 1g, fully oxidizing in a water bath at 100 ℃ for 2-4 h, repeatedly washing with distilled water for more than 8 times, and drying at 80-100 ℃ for 4-6 h; the adopted oxidant is a mixture of 3-5% by mass of potassium permanganate solution and 8-10% by mass of nitric acid solution in a volume ratio of 1: 1.
4. The wide temperature range, low friction, heat-tear resistant vinylidene fluoride rubber of claim 1,
the high-structure carbon black is one or two of carbon black N990 and spray carbon black;
the acid acceptor is selected from one of magnesium oxide or calcium hydroxide;
the vulcanizing agent is bis 2,5 or DCP;
the auxiliary crosslinking agent is triallyl isocyanurate TAIC.
5. The preparation method of the wide-temperature-range low-friction heat-tearing-resistant meta-fluoroether rubber disclosed by claim 1 is characterized by comprising the following specific steps of:
firstly plasticating the meta-fluoroether rubber on an open mill, then adding the anti-tearing auxiliary agent into the rubber, and thinly passing the rubber on the open mill after adding; placing the mixture of the rubber and the anti-tearing auxiliary agent into an internal mixer for internal mixing, firstly adding half of the amount of the high-structure carbon black and half of the amount of the wear-resistant heat-conducting filler, carrying out internal mixing for 2-3 minutes, then adding the rest of the carbon black and the rest of the wear-resistant heat-conducting filler for internal mixing for 2-3 minutes, and finally adding an acid acceptor for internal mixing for 3 minutes, wherein the temperature in the whole internal mixing process is controlled to be 50-80 ℃;
and (3) after banburying, taking out the mixture, thinly passing the mixture on an open mill for 5-8 times, discharging the mixture, standing for more than 10 hours, adding a vulcanizing agent and an auxiliary crosslinking agent on the open mill after standing, thinly passing the mixture for 6-10 times, discharging the mixture after all the vulcanizing agent and the auxiliary crosslinking agent are added, standing for more than 24 hours, and vulcanizing the mixture to obtain the dynamic seal rubber product.
6. The method for preparing a wide temperature range, low friction, heat-tear resistant, meta-fluoroether rubber according to claim 5,
the vulcanization process is divided into two stages of vulcanization: the first stage of vulcanization is carried out by adopting a vacuum plate vulcanizing machine, the vulcanization temperature is 165 ℃, the vulcanization pressure is 10Mpa, and the vulcanization time is 10min, wherein when the thickness of the product is more than 6mm, the vulcanization time is prolonged by 1min when the thickness of the product is increased by 1 mm; and the second-stage vulcanization is carried out by adopting a high-temperature oven, wherein the vulcanization temperature is 200 ℃, and the vulcanization time is 16-24 hours.
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