Perfluoroether raw rubber emulsion as well as preparation method and application thereof

Abstract

The invention discloses a perfluoroether raw rubber emulsion as well as a preparation method and application thereof, and particularly provides a preparation method of the perfluoroether raw rubber emulsion, which is characterized by comprising the following steps: (1) in the presence of a water medium, an initiator, an emulsifier and a chain transfer agent, carrying out emulsion polymerization reaction on an initial mixed monomer; (2) continuously supplementing the first-stage mixed monomer into a polymerization reaction system until the total yield of the polymerization reaction is 25-67% of the final yield; the percentage of the final yield is mass percentage; and (3) continuously supplementing the second-stage mixed monomer into the polymerization reaction system until the polymerization reaction accumulates to obtain a final product. Perfluoroether raw rubber further prepared from the perfluoroether raw rubber emulsion prepared by the preparation method has one or more advantages as follows: the perfluoroether raw rubber emulsion is resistant to high temperature, small in permanent compression deformation and good in processability, and rubber obtained after vulcanization of the perfluoroether raw rubber has better performance parameters.

Description

Technical Field

[0001] The invention relates to a perfluoroether raw rubber latex, a preparation method and application thereof. Background Art

[0002] Perfluoroether rubber is a multi-polymer made of tetrafluoroethylene, perfluoroalkyl vinyl ether and other monomers, and is known as the "king of rubber". The main chain structure of this rubber is TFE structural unit. Since the radius of the fluorine atom is half the length of the "CC" bond, its main chain has the excellent properties of polytetrafluoroethylene (PTFE) in terms of high temperature resistance and chemical resistance, and the side chain contains -OCF 3 The groups destroy the crystallinity of the main chain segments of polytetrafluoroethylene, making it have a certain elasticity and can be used in the field of elastic sealing.

[0003] This type of rubber has good resistance to oils, chemicals and high temperatures, and can be as high as 327 o It can withstand corrosion from almost all chemical media, including ethers, ketones, benzene ring solvents, strong oxidants, strong acids and alkalis (currently known to be resistant to 1,600 solvents except fluorinated solvents), but it will swell against some high-fluorocarbon solvents. If it comes into contact with gaseous or molten alkali metals, there is a risk of causing violent chemical reactions.

[0004] The high bond energy of CF bond is the main reason for the high stability of perfluoroether rubber. The high temperature compression permanent deformation performance of perfluoroether rubber is better than other fluororubbers. The excellent properties of perfluoroether rubber are widely used in many fields such as aerospace, petrochemical, atomic energy, semiconductor manufacturing, medicine, food and office equipment.

[0005] In addition to being related to the molecular structure, the performance of perfluoroether rubber is closely related to its cross-linking structure. Ordinary peroxide-cured perfluoroether rubber is mainly used in strong medium environments, and the high temperature use temperature is 230 o In the early 21st century, Italy's Solvay Company developed a high-temperature resistant perfluoroether vulcanization agent that can be cross-linked by peroxide, which improved the medium resistance and high temperature resistance of PFR95HT perfluoroether rubber, and the maximum operating temperature can reach 300 o C or above. After cyanide-cured perfluoroether rubber uses amine vulcanizers or generates triazine structures between macromolecules, the maximum operating temperature can reach 325 o C, such as the Kalrez series products of DuPont Company in the United States.

[0006] With the rapid development of my country's aerospace and high-end equipment manufacturing industries, the domestic demand for high-performance perfluoroether rubber applications has increased year by year. However, the perfluoroether rubber composite materials and products in the domestic market are mainly from DuPont in the United States, Solvay in Italy, Daikin in Japan, and well-known foreign seal suppliers Freudenberg-NOK, Parker, PPE in the United Kingdom, and Greene Tweed in the United States. DuPont's perfluoroether rubber is still the industry benchmark in the world. Its perfluoroether materials have a wide variety and coverage, and can be used in different temperatures and different media.

[0007] Nowadays, most of the research and development of domestic perfluoroether rubber focuses on the performance of materials, such as resistance to 280 o C. 300 o C and more than 300 o All perfluoroether varieties of C are under development, and there is no mature process yet. There are few reports on the emulsion polymerization mechanism of fluorinated monomers and the process of synthetic raw rubber. Therefore, it is urgent for us to conduct in-depth research on the emulsion copolymerization of fluorinated monomers, explore the copolymerization rules of gas-liquid two-phase fluorinated monomers, and synthesize high temperature resistant (325 o C) provides the core technology key and foundation for the development of high-performance fluoroether rubber. Summary of the invention

[0008] In view of the defect that the types of high temperature resistant perfluoroether rubber in the prior art are insufficient, the present invention provides a high temperature resistant perfluoroether rubber latex, a preparation method and application thereof. The perfluoroether rubber latex prepared by the preparation method of the present invention and the perfluoroether rubber further prepared have one or more of the following advantages: high temperature resistance, small permanent compression deformation and good processing performance, and the performance parameters of the rubber obtained after the perfluoroether rubber is vulcanized are also better.

[0009] The present invention mainly solves the above technical problems through the following technical solutions.

[0010] The present invention provides a method for preparing a perfluoroether raw rubber latex, which comprises the following steps:

[0011] (1) In the presence of an aqueous medium, an initiator, an emulsifier and a chain transfer agent, the initial mixed monomers undergo an emulsion polymerization reaction;

[0012] (2) continuously adding the first stage mixed monomers to the polymerization reaction system until the polymerization reaction reaches 25-67% of the final yield; the percentage of the final yield is the mass percentage;

[0013] (3) continuously adding the second stage mixed monomer to the polymerization reaction system until the polymerization reaction accumulates to a final yield;

[0014] The initial mixed monomers include tetrafluoroethylene and perfluoromethyl vinyl ether, the first stage mixed monomers include vulcanization point monomers, tetrafluoroethylene and perfluoromethyl vinyl ether, and the second stage mixed monomers include vulcanization point monomers, tetrafluoroethylene, perfluoromethyl vinyl ether and perfluorooxaalkyl vinyl ether.

[0015] As a preferred embodiment of the present invention, in the step (1), part of the initial mixed monomers are first introduced into the reaction system to make the oxygen content in the reaction system less than 30-35 ppm, and after the temperature is controlled to the reaction temperature, the initial mixed monomers are introduced to the pressure of step (1).

[0016] As a preferred embodiment of the present invention, in the step (2), the first-stage mixed monomers are added until the polymerization reaction cumulatively reacts to 27-55% of the final yield; preferably, until the polymerization reaction cumulatively reacts to 40-53% of the final yield, and further preferably, until the polymerization reaction cumulatively reacts to 44-49% of the final yield; the first-stage mixed monomers are added until the polymerization reaction cumulatively reacts to 46%-48% of the final yield; for example, 47% or 48%.

[0017] As a preferred embodiment of the present invention, the reaction time of step (2) is 1.5 to 4.5 hours; preferably 2 to 4 hours; more preferably 2.8 to 3.2 hours; for example 3 hours.

[0018] As a preferred embodiment of the present invention, the reaction time of step (3) is 3.5 to 6 hours; preferably 4.5 to 5.5 hours, for example 5 hours.

[0019] As a preferred embodiment of the present invention, the pressure in step (1) is 2.4-2.6 MPa, for example 2.5 or 2.6 MPa.

[0020] As a preferred embodiment of the present invention, step (2) is carried out when the pressure in step (1) drops by 0.2 MPa.

[0021] As a preferred embodiment of the present invention, the pressure in step (2) is 2.4-2.6 MPa, for example 2.5 or 2.6 MPa.

[0022] As a preferred embodiment of the present invention, in step (2), the first-stage mixed monomers are added to the original pressure every time the pressure of the reaction system decreases by 0.2 MPa.

[0023] As a preferred embodiment of the present invention, the pressure in step (3) is 2.7-2.9 MPa, for example, 2.7 or 2.8 MPa.

[0024] As a preferred embodiment of the present invention, in step (3), the second stage mixed monomer is continuously introduced to maintain the pressure of the reactor system.

[0025] As a preferred embodiment of the present invention, the molar ratio of tetrafluoroethylene to perfluoromethyl vinyl ether in the initial mixed monomers is (40-55):(45-60); for example, 40:60, 45:55, 50:50 or 55:45.

[0026] As a preferred embodiment of the present invention, in the step (3), before adding the second stage mixed monomer, the initial mixed monomer is introduced to the pressure of step (3), and the initiator is added, and the mass ratio of the added initiator to the aqueous medium is (0.03-0.2):100, preferably (0.06-0.15):100; for example, 0.2:300, 0.3:300 or 0.4:300.

[0027] As a preferred embodiment of the present invention, the sulfuration site monomer is a cyano-containing sulfuration site monomer, and the cyano-containing sulfuration site monomer is selected from CF 2 =CF-OR f1 -OR f2 -Combination of one or more CN, R f1 and R f2 are independently perfluoro-C 2-10 Alkylene, such as perfluoro-C 2-6 The sulfide monomer is preferably perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene) (ie, CF 2 =CF-O-CF 2 -CF(CF 3 )-O-CF 2 -CF 2 -CN, 8-CNVE);

[0028] As a preferred embodiment of the present invention, the perfluoroalkyl vinyl ether is 1-6 The perfluoroalkoxy-substituted perfluoroalkyl vinyl ether is more preferably perfluoromethoxypropyl vinyl ether.

[0029] As a preferred embodiment of the present invention, the molar ratio of tetrafluoroethylene, perfluoromethylethylene and sulfurization point monomer base ether in the first stage mixed monomer is (50-75): (25-40): (1-2); for example, 61:38:1, 65:34:1, 70:28:2 or 70:29:1.

[0030] As a preferred embodiment of the present invention, the molar ratio of tetrafluoroethylene, perfluoromethyl vinyl ether, perfluorooxyalkyl vinyl ether and vulcanization site monomer in the second stage mixed monomer is (50-75):(15-25):(5-25):(1-2); for example, 61:18:20:1, 65:20:14:1, 70:18:10:2 or 70:20:9:1.

[0031] As a preferred embodiment of the present invention, the initiator is a persulfate, for example, one or more selected from potassium persulfate, sodium persulfate, and ammonium persulfate, preferably potassium persulfate or ammonium persulfate.

[0032] As a preferred embodiment of the present invention, in step (1), the mass ratio of the added amount of the initiator to the aqueous medium is (0.05-0.3):100, more preferably (0.1-0.15):100; for example, 0.1:100.

[0033] As a preferred embodiment of the present invention, the initiator is added in batches after the polymerization reaction starts. Preferably, the initiator is added once every 15 to 30 minutes in step (2) and step (3), for example, the initiator is added once every 20 to 25 minutes. Preferably, the mass ratio of the amount of the added initiator to the aqueous medium each time is (0.01 to 0.1):100, more preferably (0.03 to 0.05):100; for example, 0.1:300 or 0.15:300.

[0034] As a preferred embodiment of the present invention, the chain transfer agent is an iodine-containing fluoroalkane I (CF 2 ) n I, wherein n=2-7; preferably, the chain transfer agent is selected from one or more of (perfluoro) 1,2-diiodoethane, 1,4-perfluorobutyl diiodide, 1,5-perfluoropentyl diiodide, 1,6-perfluorohexyl diiodide, more preferably 1,6-perfluorohexyl diiodide;

[0035] As a preferred embodiment of the present invention, the mass ratio of the added amount of the chain transfer agent to the aqueous medium is (0.05-0.3):100, more preferably (0.1-0.2):100; for example, 0.1:100, 0.13:100 or 0.2:100.

[0036] As a preferred embodiment of the present invention, the emulsifier is a mixture of perfluoropolyether peroxide and sodium octyl sulfonate, preferably the mass ratio of perfluoropolyether peroxide to sodium octyl sulfonate is 1:1; preferably, the perfluoropolyether peroxide is As a preferred embodiment of the present invention, the mass ratio of the amount of the emulsifier added to the aqueous medium is (0.01-0.3):100, more preferably (0.02-0.05):100; for example, 0.02:100, 0.07:300, 0.08:300 or 0.03:100.

[0037] As a preferred embodiment of the present invention, during the polymerization reaction, a pH regulator is further added to the polymerization reaction system, and the pH regulator is selected from a combination of one or more of ammonium carbonate, ammonium bicarbonate, dipotassium hydrogen phosphate and disodium hydrogen phosphate, preferably disodium hydrogen phosphate; preferably; the mass ratio of the added amount of the pH regulator to the aqueous medium is (0.05-1):100, more preferably (0.05-0.15):100; for example, 0.1:100, 0.07:100 or 0.05:100. The pH regulator can control the pH value of the medium within a certain range to ensure the reactivity of the initiator.

[0038] As a preferred embodiment of the present invention, the amount of the perfluoroether rubber formed by the polymerization reaction is approximately equal to the amount of the added mixed monomer, and the range is 25 to 55 parts by weight of the perfluoroether rubber per 100 parts by weight of the aqueous medium, preferably 30 to 40 parts by weight of the perfluoroether rubber per 100 parts by weight of the aqueous medium. If the weight of the perfluoroether rubber in the aqueous medium is small, the yield is too low and the cost increases; if the weight is too large, the solid content is too high, resulting in the emulsion being viscous, and the stability and heat transfer efficiency being low.

[0039] As a preferred embodiment of the present invention, the polymerization reaction is carried out under mechanical stirring, and the mechanical stirring preferably has a stirring rate of 500 to 900 rpm, more preferably 600 to 800 rpm, such as 700 rpm.

[0040] When the stirring rate is too low, the small shear force is not enough to disperse the liquid phase monomers, resulting in the appearance of larger droplets or even stratification, which limits the entry of droplets into micelles and is not conducive to polymerization. On the contrary, when the stirring rate is too high, the strong shear force will cause the emulsion to break and coagulate in the reactor, which is also not conducive to the reaction.

[0041] As a preferred embodiment of the present invention, the polymerization reaction temperature is 65 to 90 o C, preferably 80 to 85 o C; for example 80°C or 85°C.

[0042] If the temperature is below 65 o C, the polymerization speed is too slow and not suitable for large-scale industrial production. oC, which causes the initiator to decompose too quickly and cause waste. It also causes the polymerization reaction to accelerate, making the reaction process difficult to control, easily leading to heat accumulation and "explosion" phenomenon, and the segment structure of the polymer cannot be effectively controlled.

[0043] As a preferred embodiment of the present invention, the polymerization reaction is carried out in a reactor, and the space left after adding the aqueous medium into the reactor is a steam space where gaseous monomers exist, and the steam space is 30-50% of the reactor volume, preferably 40%.

[0044] As a preferred embodiment of the present invention, the step (1) comprises the following steps: in the presence of an aqueous medium, the initial mixed monomers are heated to 65-90° C. (eg, 80° C.), and then the chain transfer agent, the initiator and the emulsifier are added.

[0045] As a preferred embodiment of the present invention, the preparation method of the perfluoroether raw rubber latex comprises the following steps:

[0046] (1) In the presence of an aqueous medium, introduce part of the initial mixed monomers into the reaction system to replace the air, perform mechanical stirring, and heat until the temperature of the reaction solution stabilizes at 80-85 o C, introducing the initial mixed monomers, making the pressure of the reaction system reach 2.4-2.6 MPa, adding the first batch of initiators to initiate the polymerization reaction, and then adding emulsifiers, pH regulators and chain transfer agents; the mass ratio of the first batch of initiators to the aqueous medium is (0.1-0.15): 100;

[0047] (2) When the pressure of the reaction system drops by 0.2 MPa, the first-stage mixed monomer is added to maintain the pressure of the reaction system at 2.4-2.6 MPa until the polymerization reaction reaches 44-48% of the final yield. During this process, the initiator is added in batches every 20-25 minutes, and the mass ratio of the added initiator to the aqueous medium is (0.03-0.05):100; the polymerization reaction is maintained;

[0048] (3) The initial mixed monomers are introduced again to make the reaction pressure reach 2.7-2.9 MPa, and the second batch of initiators are added, the mass ratio of the amount of the second batch of initiators added to the water medium is (0.06-0.15):100, and polymerization is carried out. Every time the pressure of the reaction system decreases by 0.2 MPa, the second stage mixed monomers are added to maintain the pressure of the reaction system at 2.7-2.9 MPa. During this process, the initiator is added in batches every 20-25 minutes, and the mass ratio of the amount of the initiator added each time to the water medium is (0.03-0.05):100; the polymerization reaction is maintained to the final yield to prepare the perfluoroether raw rubber latex.

[0049] Preferably, except for the specially limited reaction raw materials, ratios of reaction raw materials, reaction conditions and reaction operations in the above-mentioned preparation methods, their preferred embodiments and other unrestricted reaction raw materials, ratios of reaction raw materials, reaction conditions and reaction operations are as described in any of the previous embodiments.

[0050] The method for preparing the perfluoroether raw rubber latex provided by the invention can control and adjust the structure of the prepared copolymer by using different reaction monomer ingredients in different reaction stages, thereby obtaining an emulsion product with better performance.

[0051] The present invention also provides a perfluoroether raw rubber latex, which is prepared by the above-mentioned preparation method.

[0052] The invention also provides a perfluoroether raw rubber, which is prepared by condensing the perfluoroether raw rubber latex, washing it, and vacuum drying it.

[0053] As a preferred embodiment of the present invention, the emulsion is coagulated using magnesium chloride, for example, 5%wt magnesium chloride is used for coagulation.

[0054] As a preferred embodiment of the present invention, the vacuum drying temperature is 85-110 o C, and the more preferred vacuum drying temperature is 95 o C.

[0055] As a preferred embodiment of the present invention, the perfluoroether raw rubber has a fluorine content of more than 68%, preferably more than 72%.

[0056] The present invention also provides the use of any of the above-mentioned perfluoroether raw rubbers in the preparation of rubber.

[0057] The present invention also provides a vulcanized rubber, which is obtained by vulcanizing the perfluoroether raw rubber described in any of the above schemes.

[0058] As a preferred embodiment of the present invention, the vulcanization comprises the following steps: the perfluoroether raw rubber is mixed with dipentadienyl vulcanized rubber, TAIC and carbon black N990 and then vulcanized in sections, one section vulcanization: the vulcanization condition is 170-190 o C×10 min, pressure 10~15 MPa; two-stage vulcanization: vulcanization conditions 220~240 o C×4 h to prepare the vulcanized rubber.

[0059] As a preferred embodiment of the present invention, the mixing comprises the following steps: firstly mixing the perfluoroether raw rubber with dipentadienyl vulcanized rubber, TAIC and carbon black N990 until there is no obvious difference in the rubber materials, and then mixing in a triangular bag form for 8 to 12 times.

[0060] As a preferred embodiment of the present invention, the mixing temperature does not exceed 60°C.

[0061] As a preferred embodiment of the present invention, the conditions of the first stage vulcanization are 177 o C×10 min, pressure 10~15 MPa.

[0062] As a preferred embodiment of the present invention, the second stage vulcanization condition is 230 o C×4 h.

[0063] The perfluoroether rubber synthesized by the present invention has high temperature resistance (325 o C) Small permanent compression deformation and good processing performance. Compared with the perfluoroether rubber obtained by emulsion polymerization using the same formula and direct mixing, the perfluoroether rubber prepared by the present invention has a higher heat resistance temperature. DETAILED DESCRIPTION

[0064] The technical scheme of the present invention is further described below by specific embodiments. Those skilled in the art should understand that the specific embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention. Unless otherwise specified, the technical means used in the following examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available conventional commodities.

[0065] Test method:

[0066] The tensile strength is tested using the national standards GB / T1447 and 3354-2014.

[0067] The elongation at break is based on the national standard GB / T 10654-2001.

[0068] The national standard for testing the rate of change of tensile strength is the method specified in GB 36246.

[0069] The national standard for the test of elongation at break is GB / T 228-2002.

[0070] Hardness test is based on GB / T531-2008.

[0071] The compression set test method is based on GB / T7759-1996, and the test conditions are A-type specimen 300 o C×70 h.

[0072] Raw rubber Mooney viscosity ML (1+10) 121 o C test is based on GB / T1232-2000.

[0073] Glass transition temperature T g The test is based on GB / T19466-2004.

[0074] Density test is based on national standard GB / T 1463.

[0075] The fluorine content was determined using an electrochemical method.

[0076] Preparation of perfluoropolyether peroxide:

[0077] Add 25 mL of water and 4 g of NaOH to a 100 mL flask and place in an ice-water bath with stirring.

[0078] Add 25 mL of perfluorooctane and 5.75 g of H 2 O 2 , add 33.6 g of hexafluoropropylene oxide dimer dropwise, react for three minutes after the addition is complete, and add an equal volume of NaHCO 3 , extract the lower organic phase and dry it over anhydrous sodium sulfate.

[0079] The organic phase was extracted and stored in a plastic bottle at a concentration of 0.86 mmol / mL in a refrigerator.

[0080] Example 1

[0081] This embodiment provides a perfluoroether rubber, and the specific preparation method is as follows:

[0082] 3 kg of deionized water was added to a 5 L reactor with a stirring device. Before the experiment, the activated reactor and the gas and liquid pipes connecting the reactor body were vacuumed, and the pipes and reactor body were purged with nitrogen. Then, the initial mixed monomers of tetrafluoroethylene TFE / perfluoromethyl vinyl ether PMVE = 40 / 60 (molar ratio) were introduced into the reactor using a diaphragm compressor to replace the nitrogen and make the oxygen content in the reactor less than 30 ppm.

[0083] Turn on the electromagnetic stirrer, set the heating temperature, and start stirring and heating the system. The mechanical stirring rate is 700 rpm. When the liquid temperature in the kettle stabilizes at 80 oC, the initial mixed monomer TFE / PMVE=40 / 60 (molar ratio) pre-packed in proportion was pressed into the reactor by a diaphragm compression pump, so that the pressure of the reactor reached 2.5 Mpa, and the reaction pressure was controlled well. 3 g of initiator ammonium persulfate (2M, aqueous solution) was injected into the reactor to start polymerization. 0.6 g of emulsifier, which was a mixture of perfluoropolyether peroxide and sodium octyl sulfonate in a mass ratio of 1:1, as well as 1.5 g of pH regulator disodium hydrogen phosphate and 3 g of chain transfer agent 1,6-perfluorohexyl diiodide (CAS: 375-80-4) were added, and heated to 80 o C.

[0084] The experiment adopted a continuous emulsion copolymerization scheme. As the polymerization proceeded, the mixed monomers of the first reaction stage were added to the original pressure every time the system pressure dropped by 0.2 Mpa. The mixed monomers of the first reaction stage TFE / PMVE / 8-CNVE=61 / 38 / 1 (molar ratio) were added to the reactor through a diaphragm compression pump to maintain a constant pressure in the reactor; and 1 g of initiator potassium persulfate was added every 20 min to maintain the effective reaction. After 3 hours of polymerization, the second reaction stage was entered, and the addition of the mixed monomers of the first reaction stage was stopped, and the unreacted monomers in the reactor were recovered.

[0085] Then, the initial mixed monomer TFE / PMVE=40 / 60 (molar ratio) was introduced into the reactor, and when the pressure in the reactor reached 2.8 MPa, 2 g of initiator potassium persulfate was added to carry out polymerization reaction. The mixed monomer TFE / PMVE / 8-CNVE / PAVE=61 / 18 / 1 / 20 (molar ratio) of the second reaction stage was continuously introduced, and during the polymerization reaction, 1 g of initiator potassium persulfate was added every 20 min to maintain the reaction for five hours. Among them, PAVE (perfluorooxyalkyl vinyl ether) is perfluoromethoxypropyl vinyl ether (CAS: 40573-09-9).

[0086] During the polymerization process, it is necessary to pay attention to the changes in the system temperature. Especially for monomers with strong reaction activity, a moderate amount of heat will be released during the emulsion polymerization. If it is not controlled in time, it will cause local overheating, accelerate the decomposition of the initiator, and even cause "explosion". Therefore, it is necessary to control and record the reaction temperature at all times. In addition, during the experiment, it is necessary to accurately record the changes in the pressure in the system over time. After the second stage of the reaction is completed, stop adding the mixed monomers. When the system pressure drops to 1.9MPa, stop stirring. Wait until it cools to a safe temperature and start discharging. Recover the unreacted monomers in the reactor. The materials flowing out of the coil reactor enter the product collection device to obtain perfluoroether raw rubber latex. Add 5%wt magnesium chloride to the prepared perfluoroether raw rubber latex for condensation, then wash, and then heat at 95 oC and dried under vacuum for 24 h to obtain 1.3 kg of perfluoroether raw rubber product.

[0087] The percentage of the mass of the product at the completion of the first stage reaction to the mass of the product at the completion of the second stage reaction is 47%.

[0088] Example 2

[0089] This embodiment provides a perfluoroether rubber, and the specific preparation method is as follows:

[0090] 3 kg of deionized water was added to a 5 L reactor with a stirring device. Before the experiment, the activated reactor and the gas and liquid pipes connecting the reactor body were vacuumed, and the pipes and reactor body were purged with nitrogen. Then, the initial mixed monomers of tetrafluoroethylene TFE / perfluoromethyl vinyl ether PMVE = 45 / 55 (molar ratio) were introduced into the reactor using a diaphragm compressor to replace the nitrogen and make the oxygen content in the reactor less than 30 ppm.

[0091] Turn on the electromagnetic stirrer, set the heating temperature, and start stirring and heating the system. The mechanical stirring rate is 700 rpm. When the liquid temperature in the kettle stabilizes at 85 o C, the initial mixed monomer TFE / PMVE=45 / 55 (molar ratio) pre-packed in proportion was pressed into the reactor by a diaphragm compression pump, so that the pressure of the reactor reached 2.6 Mpa, and the reaction pressure was controlled well. 3 g of initiator ammonium persulfate (2M aqueous solution) was injected into the reactor to start polymerization. 0.7 g of emulsifier, which was a mixture of perfluoropolyether peroxide and sodium octyl sulfonate in a mass ratio of 1:1, as well as 2 g of disodium hydrogen phosphate as a pH adjuster and 4 g of 1,6-perfluorohexyl diiodide as a chain transfer agent were added, and heated to 85 o C.

[0092] The experiment adopted a continuous emulsion copolymerization scheme. As the polymerization proceeded, the mixed monomers of the first reaction stage were added to the original pressure every time the system pressure dropped by 0.2 Mpa. The mixed monomers of the first reaction stage TFE / PMVE / 8-CNVE=65 / 34 / 1 (molar ratio) were added to the reactor through a diaphragm compression pump to maintain a constant pressure in the reactor; and 1 g of initiator potassium persulfate was added every 20 min to maintain the effective reaction. After 3 hours of polymerization, the second reaction stage was entered, and the addition of the mixed monomers of the first reaction stage was stopped, and the unreacted monomers in the reactor were recovered.

[0093] Then, the initial mixed monomer TFE / PMVE=45 / 55 (molar ratio) was introduced into the reactor, and when the pressure in the reactor reached 2.8 MPa, 2 g of initiator potassium persulfate was added to carry out polymerization reaction. The mixed monomer TFE / PMVE / 8-CNVE / PAVE=65 / 20 / 1 / 14 (molar ratio) of the second reaction stage was continuously introduced, and during the polymerization reaction, 1.5 g of initiator potassium persulfate was added every 20 min to maintain the reaction for five hours. Among them, PAVE (perfluorooxyalkyl vinyl ether) is perfluoromethoxypropyl vinyl ether.

[0094] During the polymerization process, it is necessary to pay attention to the changes in the system temperature. Especially for monomers with strong reaction activity, there will be a moderate amount of heat release during the emulsion polymerization. If it is not controlled in time, it will cause local overheating, accelerate the decomposition of the initiator, and even cause "explosion". Therefore, it is necessary to control and record the reaction temperature at all times. In addition, the pressure changes in the system over time must be accurately recorded during the experiment. After the second stage of the reaction is completed, stop adding the mixed monomers. When the system pressure drops to 1.9MPa, stop stirring. Wait until it cools to a safe temperature and start discharging. Recover the unreacted monomers in the reactor. The material flowing out of the coil reactor enters the product collection device to obtain a perfluoroether rubber latex.

[0095] 5%wt magnesium chloride was added to the obtained perfluoroether rubber latex for coagulation, followed by washing and then heating at 95 o C and dried under vacuum for 24 h to obtain 1.4 kg of perfluoroether raw rubber product.

[0096] The percentage of the mass of the product at the completion of the first stage reaction to the mass of the product at the completion of the second stage reaction is 48%.

[0097] Example 3

[0098] This embodiment provides a perfluoroether rubber latex, and the specific preparation method is as follows:

[0099] 3 kg of deionized water was added to a 5 L reactor with a stirring device. Before the experiment, the activated reactor and the gas and liquid pipes connecting the reactor body were vacuumed, and the pipes and reactor body were purged with nitrogen. Then, the initial mixed monomers of tetrafluoroethylene TFE / perfluoromethyl vinyl ether PMVE = 50 / 50 (molar ratio) were introduced into the reactor using a diaphragm compressor to replace the nitrogen and make the oxygen content in the reactor less than 30 ppm.

[0100] Turn on the electromagnetic stirrer, set the heating temperature, and start stirring and heating the system. The mechanical stirring rate is 700 rpm. When the liquid temperature in the kettle stabilizes at 80 oC, the initial mixed monomer TFE / PMVE=50 / 50 (molar ratio) pre-packed in proportion was pressed into the reactor by a diaphragm compression pump, so that the pressure of the reactor reached 2.5 MPa, and the reaction pressure was controlled well. 3 g of initiator ammonium persulfate aqueous solution was injected into the reactor to start polymerization. 0.9 g of emulsifier, which was a mixture of perfluoropolyether peroxide and sodium octyl sulfonate in a mass ratio of 1:1, as well as 3 g of pH regulator dipotassium hydrogen phosphate and 6 g of chain transfer agent 1,6-perfluorohexyl diiodide were added, and heated to 85 o C.

[0101] The experiment adopted a continuous emulsion copolymerization scheme. As the polymerization proceeded, the mixed monomers of the first reaction stage were added to the original pressure every time the system pressure dropped by 0.2 Mpa. The mixed monomers of the first reaction stage TFE / PMVE / 8-CNVE=70 / 28 / 2 (molar ratio) were added to the reactor through a diaphragm compression pump to maintain a constant pressure in the reactor; and 1.5 g of initiator potassium persulfate was added every 25 min to maintain the effective reaction. After 3 hours of polymerization, the second reaction stage was entered, and the addition of the mixed monomers of the first reaction stage was stopped, and the unreacted monomers in the reactor were recovered.

[0102] Then enter the second reaction stage, introduce the initial mixed monomer TFE / PMVE=50 / 50 (molar ratio) into the reactor, and when the pressure in the reactor is 2.8 MPa, add 4 g of initiator potassium persulfate to carry out polymerization reaction. Continue to introduce the mixed monomer TFE / PMVE / 8-CNVE / PAVE=70 / 18 / 2 / 10 (molar ratio), and during the polymerization reaction, add 1.5 g of initiator potassium persulfate every 25 min to maintain the reaction for five hours. PAVE (perfluorooxyalkyl vinyl ether) is perfluoromethoxypropyl vinyl ether.

[0103] During the polymerization process, it is necessary to pay attention to the changes in the system temperature. Especially for monomers with strong reaction activity, there will be a moderate amount of heat release during the emulsion polymerization. If it is not controlled in time, it will cause local overheating, accelerate the decomposition of the initiator, and even cause "explosion". Therefore, it is necessary to control and record the reaction temperature at all times. In addition, the pressure changes in the system over time must be accurately recorded during the experiment. After the second stage of the reaction is completed, stop adding the mixed monomers. When the system pressure drops to 1.9MPa, stop stirring. Wait until it cools to a safe temperature and start discharging. Recover the unreacted monomers in the reactor. The material flowing out of the coil reactor enters the product collection device to obtain a perfluoroether rubber latex.

[0104] 5%wt magnesium chloride was added to the obtained perfluoroether rubber latex for coagulation, followed by washing and then heating at 95 oC and dried under vacuum for 24 h to obtain 1.2 kg of perfluoroether raw rubber product.

[0105] The percentage of the mass of the product at the completion of the first stage reaction to the mass of the product at the completion of the second stage reaction is 47%.

[0106] Example 4

[0107] This embodiment provides a perfluoroether rubber latex, and the specific preparation method is as follows:

[0108] 3 kg of deionized water was added to a 5 L reactor with a stirring device. Before the experiment, the activated reactor and the gas and liquid pipes connecting the reactor body were vacuumed, and the pipes and reactor body were purged with nitrogen. Then, the initial mixed monomers of tetrafluoroethylene TFE / perfluoromethyl vinyl ether PMVE = 55 / 45 (molar ratio) were introduced into the reactor using a diaphragm compressor to replace the nitrogen and make the oxygen content in the reactor less than 30 ppm.

[0109] Turn on the electromagnetic stirrer, set the heating temperature, and start stirring and heating the system. The mechanical stirring rate is 700 rpm. When the liquid temperature in the kettle stabilizes at 80 o C, the initial mixed monomer TFE / PMVE=55 / 45 (molar ratio) pre-packed in proportion was pressed into the reactor by a diaphragm compression pump, so that the pressure of the reactor reached 2.6 Mpa, and the reaction pressure was controlled at the same time. 3 g of initiator ammonium persulfate aqueous solution was injected into the reactor to start polymerization. 0.8 g of emulsifier, which was a mixture of perfluoropolyether peroxide and sodium octyl sulfonate in a mass ratio of 1:1, as well as 2 g of pH regulator dipotassium hydrogen phosphate and 4 g of chain transfer agent 1,6-perfluorohexyl diiodide were added, and heated to 85 o C.

[0110] The experiment adopted a continuous emulsion copolymerization scheme. As the polymerization proceeded, the system pressure was supplemented to the original pressure every time it dropped by 0.2 Mpa. The mixed monomers TFE / PMVE / 8-CNVE=70 / 29 / 1 (molar ratio) of the first reaction stage were added to the reactor through a diaphragm compression pump to maintain a constant pressure in the reactor; and 1 g of initiator potassium persulfate was added every 25 minutes to maintain the effective reaction. After 3 hours of polymerization, the second reaction stage was entered, and the addition of the mixed monomers of the first reaction stage was stopped, and the unreacted monomers in the reactor were recovered.

[0111] Then enter the second reaction stage, introduce the initial mixed monomer TFE / PMVE=55 / 45 (molar ratio) into the reactor, and when the pressure in the reactor is 2.7 MPa, add 3 g of initiator potassium persulfate to carry out polymerization reaction. Continue to introduce the mixed monomer TFE / PMVE / 8-CNVE / PAVE=70 / 20 / 1 / 9 (molar ratio), and during the polymerization reaction, add 1 g of initiator potassium persulfate every 25 minutes to maintain the reaction for five hours. Among them, PAVE (perfluorooxyalkyl vinyl ether) is perfluoromethoxypropyl vinyl ether.

[0112] During the polymerization process, it is necessary to pay attention to the changes in the system temperature. Especially for monomers with strong reaction activity, there will be a moderate amount of heat release during the emulsion polymerization. If it is not controlled in time, it will cause local overheating, accelerate the decomposition of the initiator, and even cause "explosion". Therefore, it is necessary to control and record the reaction temperature at all times. In addition, the pressure changes in the system over time must be accurately recorded during the experiment. After the second stage of the reaction is completed, stop adding the mixed monomers. When the system pressure drops to 1.9MPa, stop stirring. Wait until it cools to a safe temperature and start discharging. Recover the unreacted monomers in the reactor. The material flowing out of the coil reactor enters the product collection device to obtain a perfluoroether rubber latex.

[0113] 5%wt magnesium chloride was added to the obtained perfluoroether rubber latex for coagulation, followed by washing and then heating at 95 o C and dried under vacuum for 24 h to obtain 1.1 kg of perfluoroether raw rubber product.

[0114] The percentage of the mass of the product at the completion of the first stage reaction to the mass of the product at the completion of the second stage reaction is 47%.

[0115] Embodiments 5 to 10

[0116] According to the steps of Example 1, the reaction was carried out in a 5 L reactor, and the different reaction conditions are shown in Table 1. Wherein PAVE (perfluorooxyalkyl vinyl ether) is perfluoromethoxypropyl vinyl ether.

[0117] Taking the total reaction time of 8 hours as the standard, the time of the first reaction stage was changed, and the performance parameters of the raw rubber were tested as shown in Table 1.

[0118] Table 1

[0119]

[0120] The percentage of yield to final yield refers to the percentage of the mass of the product when the first stage reaction is completed to the mass of the product when the second stage reaction is completed.

[0121] Examples 11 to 17

[0122] According to the steps of Example 1, the reaction was carried out in a 5 L reactor, and the different reaction conditions are shown in Table 2. Wherein PAVE is perfluoromethoxypropyl vinyl ether.

[0123] Taking the first reaction stage time of 3 hours as the standard, the total reaction time was changed and the performance parameters of the raw rubber were tested as shown in Table 2.

[0124] Table 2

[0125]

[0126] Embodiment 18

[0127] The various properties of the raw rubber obtained in Examples 1-4 were tested, and the results are shown in Table 3.

[0128] The perfluoroether raw rubber obtained in Examples 1-4 was vulcanized, and the performance of the vulcanized rubber product was tested. The testing steps are as follows:

[0129] (1) Perfluoroether rubber (100 phr) was heated at 25 o The raw rubber was plasticized and thinned on an open rubber mixing mill for 6 to 8 times, and the processing properties of the raw rubber were observed to obtain the processing properties parameters of the raw rubber such as "temperature when wrapping the roll" and "dripping during the wrapping process".

[0130] (2) Add 2-pentadienyl vulcanizate (4 phr), TAIC (3 phr), and carbon black N990 (30 phr) and mix until there is no obvious difference in the rubber. Then mix in a triangle bag for 8 to 12 times. The mixing temperature should not exceed 60 o C. The film is vulcanized in sections, one section vulcanization: vulcanization conditions 177 o C×10 min, pressure 10~15 MPa; Second stage vulcanization: vulcanization conditions: normal pressure 230 o C×4 h, and then conduct the following data test analysis.

[0131] Method for determining the processing performance of raw rubber: observe at what temperature the raw rubber can be quickly rolled on an open mixing mill, and measure the temperature of the raw rubber with a handheld infrared induction thermometer; and weigh the weight of flocculent, granular or blocky drops (less than 10x10x10 mm in size) of the raw rubber during the entire rolling process.

[0132] Table 3

[0133]

[0134] The test results show that the perfluoroether raw rubber provided in this application has a high fluorine content and good mechanical properties. After aging at 325°C × 24h, the change rate of tensile strength and the change rate of elongation at break are both low, and various parameters after forming vulcanized rubber are also better.

[0135] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a perfluoroether rubber latex, characterized in that: It includes the following steps: (1) In the presence of an aqueous medium, an initiator, an emulsifier and a chain transfer agent, the initial mixed monomers undergo an emulsion polymerization reaction; (2) continuously adding the first stage mixed monomers to the polymerization reaction system until the polymerization reaction reaches 25-67% of the final yield; the percentage of the final yield is the percentage by mass; (3) continuously adding the second stage mixed monomer to the polymerization reaction system until the polymerization reaction accumulates to a final yield; The initial mixed monomers include tetrafluoroethylene and perfluoromethyl vinyl ether, the first stage mixed monomers include vulcanization point monomers, tetrafluoroethylene and perfluoromethyl vinyl ether; the second stage mixed monomers include vulcanization point monomers, tetrafluoroethylene, perfluoromethyl vinyl ether and perfluorooxaalkyl vinyl ether.

2. The method for preparing a perfluoroether rubber latex according to claim 1, wherein: It meets one or more of the following conditions: (1) In step (1), a portion of the initial mixed monomers is first introduced into the reaction system to make the oxygen content in the reaction system less than 30-35 ppm. After the temperature is controlled to the reaction temperature, the initial mixed monomers are introduced to the pressure of step (1); (2) In step (2), the first stage mixed monomer is added until the cumulative polymerization reaction reaches 27-55% of the final yield; (3) The reaction time of step (2) is 1.5 to 4.5 hours; (4) The reaction time of step (3) is 3.5 to 6 hours; (5) The pressure in step (1) is 2.4-2.6 MPa; (6) When the pressure in step (1) drops by 0.2 MPa, proceed to step (2); (7) The pressure in step (2) is 2.4-2.6 MPa; (8) In step (2), the first-stage mixed monomer is added to the original pressure every time the pressure of the reaction system drops by 0.2 MPa; (9) The pressure in step (3) is 2.7-2.9 MPa; (10) In step (3), the second stage mixed monomer is continuously introduced to maintain the pressure of the reactor system; (11) The molar ratio of tetrafluoroethylene to perfluoromethyl vinyl ether in the initial mixed monomer is (40-55): (45-60); (12) In step (3), before adding the second stage mixed monomer, the initial mixed monomer is introduced to the pressure of step (3); (13) The sulfurization site monomer is a sulfurization site monomer containing a cyano group; (14) The perfluoroalkyl vinyl ether is a 1-6 Perfluoroalkoxy-substituted perfluoroalkyl vinyl ethers; (15) The molar ratio of tetrafluoroethylene, perfluoromethylethylene and sulfurization point monomer base ether in the first stage mixed monomer is (50-75): (25-40): (1-2); (16) The molar ratio of tetrafluoroethylene, perfluoromethyl vinyl ether, perfluorooxyalkyl vinyl ether and vulcanization site monomer in the second stage mixed monomer is (50-75): (15-25): (5-25): (1-2); (17) The initiator is a persulfate; (18) In step (1), the mass ratio of the added amount of the initiator to the aqueous medium is (0.05-0.3):100; (19) adding initiator in batches after the polymerization reaction starts; (20) The chain transfer agent is an iodine-containing fluoroalkane I (CF2) n I, wherein n=2 to 7; (21) The mass ratio of the added amount of the chain transfer agent to the aqueous medium is (0.05-0.3):100; (22) The emulsifier is a mixture of perfluoropolyether peroxide and sodium octyl sulfonate; (23) The mass ratio of the added amount of the emulsifier to the aqueous medium is (0.01-0.3):100; (24) A pH regulator is also added to the polymerization reaction system; (25) The amount of the perfluoroether rubber formed by the polymerization reaction is in the range of 25 to 55 parts by weight of the perfluoroether rubber per 100 parts by weight of the aqueous medium; (26) The polymerization reaction is carried out under mechanical stirring; (27) The polymerization reaction temperature is 65 to 90 o C; (28) The polymerization reaction is carried out in a reactor, and the space left after the aqueous medium is added to the reactor is a vapor space where the gaseous monomer exists.

3. The method for preparing a perfluoroether rubber latex according to claim 2, wherein: It meets one or more of the following conditions: (1) In step (2), the first-stage mixed monomer is added until the polymerization reaction reaches a cumulative reaction of 40-53% of the final yield, and more preferably, until the polymerization reaction reaches a cumulative reaction of 44-49% of the final yield; the first-stage mixed monomer is added until the polymerization reaction reaches a cumulative reaction of 46%-48% of the final yield; for example, 47% or 48%; (2) The reaction time of step (2) is 2 to 4 hours; more preferably 2.8 to 3.2 hours; for example 3 hours; (3) The reaction time of step (3) is 4.5 to 5.5 hours, for example, 5 hours; (4) The pressure in step (1) is 2.5 or 2.6 MPa; (5) The pressure in step (2) is 2.5 or 2.6 MPa; (6) The pressure in step (3) is 2.7 or 2.8 MPa; (7) The molar ratio of tetrafluoroethylene to perfluoromethyl vinyl ether in the initial mixed monomers is 40:60, 45:55, 50:50 or 55:45; (8) In step (3), before adding the second stage mixed monomer, the initial mixed monomer is introduced to the pressure of step (3), and the initiator is added. The mass ratio of the added initiator to the aqueous medium is (0.03-0.2):100, preferably (0.06-0.15):100; for example, 0.2:300, 0.3:300 or 0.4:300; (9) The cyano-containing sulfurization site monomer is selected from CF2=CF-OR f1 -OR f2 -Combination of one or more CN, R f1 and R f2 are independently perfluoro-C 2-10 Alkylene, such as perfluoro-C 2-6 Alkylene; the sulfurization site monomer is preferably perfluoro(8-cyano-5-methyl-3,6-dioxa-1-octene); (10) The perfluorooxaalkyl vinyl ether is perfluoromethoxypropyl vinyl ether; (11) The molar ratio of tetrafluoroethylene, perfluoromethylethylene and sulfurization site monomer base ether in the first stage mixed monomer is 61:38:1, 65:34:1, 70:28:2 or 70:29:1; (12) the molar ratio of tetrafluoroethylene, perfluoromethyl vinyl ether, perfluorooxaalkyl vinyl ether and the curing site monomer in the second stage mixed monomer is 61:18:20:1, 65:20:14:1, 70:18:10:2 or 70:20:9:1; (13) The initiator is one or more of potassium persulfate, sodium persulfate, and ammonium persulfate, preferably potassium persulfate or ammonium persulfate; (14) In the step (1), the mass ratio of the added amount of the initiator to the aqueous medium is (0.1-0.15):100; for example, 0.1:100; (15) After the polymerization reaction begins, the initiator is added once every 15 to 30 minutes in step (2) and step (3); for example, the initiator is added once every 20 to 25 minutes; preferably, the mass ratio of the amount of the added initiator to the aqueous medium is (0.01 to 0.1):100, more preferably (0.03 to 0.05):100; for example, 0.1:300 or 0.15:300; (16) The chain transfer agent is one or more selected from (perfluoro) 1,2-diiodoethane, 1,4-perfluorobutyl diiodide, 1,5-perfluoropentyl diiodide, 1,6-perfluorohexyl diiodide, more preferably 1,6-perfluorohexyl diiodide; (17) The mass ratio of the added amount of the chain transfer agent to the aqueous medium is (0.1-0.2):100; for example, 0.1:100, 0.13:100 or 0.2:100; (18) The mass ratio of the emulsifier to sodium octyl sulfonate is 1:1; preferably, the perfluoropolyether peroxide is ; (19) The mass ratio of the amount of the emulsifier added to the aqueous medium is (0.02-0.05):100; for example, 0.02:100, 0.07:300, 0.08:300 or 0.03:100; (20) The pH regulator is selected from a combination of one or more of ammonium carbonate, ammonium bicarbonate, dipotassium hydrogen phosphate and disodium hydrogen phosphate, preferably disodium hydrogen phosphate; preferably, the mass ratio of the added amount of the pH regulator to the aqueous medium is (0.05-1):100, more preferably (0.1-0.15):100; (21) The amount of the perfluoroether rubber formed by the polymerization reaction is in the range of 30 to 40 parts by weight of the perfluoroether rubber per 100 parts by weight of the aqueous medium; (22) The mechanical stirring preferably has a stirring rate of 500 to 900 rpm, more preferably 600 to 800 rpm, for example 700 rpm; (23) The polymerization reaction temperature is 80 to 85 o C; for example 80°C or 85°C; (24) The steam space is 30% to 50% of the volume of the reactor, preferably 40%.

4. The method for preparing the perfluoroether rubber latex according to claim 3, wherein: The step (1) comprises the following steps: In the presence of the aqueous medium, the initial mixed monomers are heated to 65-90° C. (e.g., 80° C.), and then the chain transfer agent, the initiator, and the emulsifier are added; Preferably, the preparation method comprises the following specific steps: (1) In the presence of the aqueous medium, a portion of the initial mixed monomers is introduced into the reaction system to replace the air, and mechanical stirring and heating are performed until the temperature of the reaction liquid is stabilized at 80 to 85 o C, introducing the initial mixed monomers to make the pressure of the reaction system reach 2.4-2.6 MPa, adding the first batch of initiators to initiate the polymerization reaction, and then adding emulsifiers, pH regulators and chain transfer agents; the mass ratio of the first batch of initiators to the aqueous medium is (0.1-0.15):100; (2) When the pressure of the reaction system drops by 0.2 MPa, the first-stage mixed monomer is added to maintain the pressure of the reaction system at 2.4-2.6 MPa until the polymerization reaction reaches 44-48% of the final yield. During this process, the initiator is added in batches every 20-25 minutes, and the mass ratio of the added initiator to the aqueous medium is (0.03-0.05):100; the polymerization reaction is maintained; (3) The initial mixed monomers are introduced again to make the reaction pressure reach 2.7-2.9 MPa, and the second batch of initiators are added, the mass ratio of the added amount of the second batch of initiators to the aqueous medium is (0.06-0.1) : 100, and polymerization is carried out. Every time the pressure of the reaction system decreases by 0.2 MPa, the second stage mixed monomers are added to maintain the pressure of the reaction system at 2.7-2.9 MPa. During this process, the initiator is added in batches every 20-25 minutes, and the mass ratio of the added amount of the initiator each time to the aqueous medium is (0.03-0.05) : 100; the polymerization reaction is maintained to the final yield to prepare the perfluoroether rubber latex.

5. A perfluoroether rubber latex, characterized in that: The invention is prepared by the preparation method described in any one of claims 1 to 4.

6. A perfluoroether rubber, characterized in that: The method is prepared by coagulating the perfluoroether rubber latex as claimed in claim 5, washing the latex, and vacuum drying the latex.

7. The perfluoroether rubber as claimed in claim 6, characterized in that It meets one or more of the following conditions; (1) The emulsion is subjected to a coagulation treatment using magnesium chloride, for example, 5%wt magnesium chloride is used for the coagulation treatment; (2) The vacuum drying temperature is 85 to 110 o C, and the more preferred vacuum drying temperature is 95 o C; (3) The perfluoroether rubber has a fluorine content of 68% or more, preferably 72% or more.

8. Use of the perfluoroether rubber as claimed in claim 7 in the preparation of rubber.

9. A vulcanized rubber, characterized in that: The method is obtained by vulcanizing the perfluoroether raw rubber as claimed in claim 7.

10. The vulcanized rubber according to claim 9, characterized in that It meets one or more of the following conditions: (1) The vulcanization comprises the following steps: the perfluoroether rubber is mixed with dipentadienyl vulcanized rubber, TAIC and carbon black N990 and then vulcanized in stages, one stage vulcanization: the vulcanization condition is 170-190 o C×10 min, pressure 10~15 MPa; two-stage vulcanization: vulcanization conditions 220~240 o C×4 h, to prepare the vulcanized rubber; (2) The mixing comprises the following steps: firstly mixing the perfluoroether raw rubber with dipentadienyl vulcanized rubber, TAIC and carbon black N990 until there is no obvious difference in the rubber materials, and then mixing them in a triangular bag form for 8 to 12 times; (3) The mixing temperature does not exceed 60°C; (4) The first stage vulcanization condition is 177 o C×10 min, pressure 10~15 MPa; (5) The second stage vulcanization condition is 230 o C×4 h.

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