High temperature resistant perfluoroether rubber, its preparation method and use

Abstract

The application discloses a kind of high-temperature-resistant perfluoroether rubber and its preparation method and purposes, belong to fluorine rubber material technical field.The application provides a kind of fluorine-free surfactant for preparing high-temperature-resistant perfluoroether rubber.The perfluoroether rubber prepared by the fluorine-free surfactant of the application has excellent mechanical properties and heat aging resistance, and is comparable to the performance of fluorine rubber synthesized by using perfluorooctanoic acid surfactant, with the potential to replace perfluorooctanoic acid surfactant.The fluorine-free surfactant of the application avoids the harm of traditional fluorine-containing surfactant to the environment and human health;It is cheap, easy to industrial production;Using high-pressure emulsion polymerization technology, stable emulsion can be obtained, which is conducive to controlling polymerization reaction, and has good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluororubber materials, and particularly relates to a high-temperature-resistant perfluoroether rubber as well as a preparation method and application thereof. BACKGROUND

[0002] Perfluoroether rubber (FFKM) is a special rubber polymerized from perfluoroether monomers, which has excellent high-temperature resistance, chemical corrosion resistance, oil resistance and solvent resistance, and is widely used in high-end fields such as aerospace, petrochemical industry and semiconductor. However, fluorine-containing surfactants such as perfluorooctanoic acid ammonium (PFOA) and perfluorooctane sulfonic acid (PFOS) are usually used in the preparation process of traditional FFKM, which has environmental persistence, biological accumulation and toxicity, and can cause serious harm to the environment and human health.

[0003] At present, there have been some reports on the preparation of FFKM without fluorine-containing surfactants, such as using hydrocarbon surfactants, sodium alkyl sulfate and sodium alkyl benzene sulfonate, but the emulsifying effect of these surfactants is poor, it is difficult to obtain stable emulsion, the polymerization reaction is difficult to control, the product has wide molecular weight distribution and poor performance. Using siloxane surfactants such as polyether modified silicone oil, although these surfactants have good emulsifying effect, but the price is expensive, it is difficult to realize industrial application.

[0004] Therefore, it is of great practical significance to develop a high-efficiency, environmentally friendly and low-cost method for preparing FFKM without fluorine-containing surfactants. SUMMARY

[0005] In order to solve the above-mentioned problems existing in the prior art, the purpose of the present application is to provide a high-temperature-resistant perfluoroether rubber as well as a preparation method and application thereof.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a fluorine-free surfactant, which is prepared from an alcohol compound, a hydroxyl-containing halogenated alkyl sulfonate and an alkaline reagent, and the mass ratio of the alcohol compound, the hydroxyl-containing halogenated alkyl sulfonate and the alkaline reagent is (10-30):(10-40):(10-30).

[0008] Further, the mass ratio of the alcohol compound, the hydroxyl-containing halogenated alkyl sulfonate and the alkaline reagent is 20:25:20; the alcohol compound is R-OH, R is selected from C 2-6 alkyl, the hydroxyl-containing halogenated alkyl sulfonate is sodium hydroxyl-containing halogenated alkyl sulfonate, and the alkaline reagent is at least one of NaH, CaH2, KH and n-butyllithium.

[0009] In the present application, C 2-6 The alkyl group includes straight-chain or branched alkyl groups having 2-6 carbon atoms.

[0010] Further, the alcohol compound is 2-methyl 1-pentanol, the hydroxyl-containing halogenated alkyl sulfonate is sodium 3-chloro 2-hydroxypropanesulfonate, and the basic reagent is NaH.

[0011] The present application also provides a preparation method of the above-mentioned fluorine-free surfactant, and the preparation method is as follows:

[0012] (1) reacting the alcohol compound with the basic reagent;

[0013] (2) adding the hydroxyl-containing halogenated alkyl sulfonate after the reaction in step (1) is completed, and then reacting to obtain the fluorine-free surfactant.

[0014] Further, the reaction in step (1) is protected by an inert medium, the reaction solvent is tetrahydrofuran, the reaction temperature is -10-15℃, and the reaction time is 0.2-5h.

[0015] The reaction in step (2) is protected by an inert medium, the reaction temperature is -10-15℃, and the reaction time is 10-40h.

[0016] Further, the inert medium in step (1) is nitrogen, the reaction temperature is 0-5℃, and the reaction time is 1h.

[0017] The inert medium in step (2) is nitrogen, the reaction temperature is 0-5℃, and the reaction time is 24h.

[0018] The present application also provides a perfluoroether rubber, which is prepared from perfluoroether rubber raw rubber, a vulcanizing agent, an accelerator, a filler and an internal release agent; and the mass ratio of the perfluoroether rubber raw rubber, the vulcanizing agent, the accelerator, the filler and the internal release agent is (50-200):(0.1-10):(0.1-10):(5-50):(0.1-10).

[0019] The perfluoroether rubber raw rubber is prepared from the above-mentioned fluorine-free surfactant, mixed monomers, an initiator and a chain transfer agent, and the mass ratio of the fluorine-free surfactant, the mixed monomers, the initiator and the chain transfer agent is (1-50):(100-300):(1-20):(0.1-10); and the mixed monomers are perfluoromethyl vinyl ether, tetrafluoroethylene and I(CF2)2OCF=CF2.

[0020] Further, the mass ratio of the perfluoroether rubber raw rubber, the vulcanizing agent, the accelerator, the filler and the internal release agent is 100:3:1:18:1.

[0021] The mass ratio of the fluorine-free surfactant, the mixed monomer, the initiator and the chain transfer agent is (8-20):200:8:1.

[0022] The molar ratio of the perfluoromethyl vinyl ether, tetrafluoroethylene and I(CF2)2OCF=CF2 is (5-50):(50-200):1; the initiator is at least one of diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, tert-butyl peroxy pivalate, azobis isobutyronitrile, and the chain transfer agent is at least one of diiodomethane, 1,2-diiodoethane, perfluorohexyl iodide, perfluorobutyl iodide, 1,4-diiodooctafluorobutane;

[0023] The vulcanizing agent is at least one of triallyl isocyanurate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, m-phenylene bismaleimide; the accelerator is at least one of 2,5-di-tert-butyl peroxy-2,5-dimethylhexane, dicumyl peroxide, bis(tert-butylperoxy isopropyl) benzene, benzoyl peroxide, the filler is carbon black, and the internal release agent is a fluorine-containing polyether derivative;

[0024] Further, the molar ratio of the perfluoromethyl vinyl ether, tetrafluoroethylene and I(CF2)2OCF=CF2 is (13.5-38.5):(85.5-110.5):1; the initiator is diisopropyl peroxydicarbonate, and the chain transfer agent is diiodomethane;

[0025] The vulcanizing agent is triallyl isocyanurate, and the accelerator is 2,5-di-tert-butyl peroxy-2,5-dimethylhexane.

[0026] The application also provides a preparation method of the perfluoroether rubber, and the preparation method is as follows:

[0027] (1) the fluorine-free surfactant, the mixed monomer and the initiator are reacted, the chain transfer agent is added, and the reaction is continued to obtain the perfluoroether rubber raw rubber;

[0028] The reaction time is 0.5-5h, the reaction pressure is 1.0-10.0MPa, and the reaction temperature is 50-120℃;

[0029] The continued reaction time is 5-20h, the reaction pressure is 1.0-10.0MPa, and the reaction temperature is 50-120℃.

[0030] (2) the perfluoroether rubber raw rubber thin pass plasticizing 1-5 times, adding accelerator, filler, internal release agent, mixing, adding vulcanizing agent mixing, storing, re-mixing, obtaining perfluoroether rubber;

[0031] The mixing is thin pass plasticizing 1-10 times, the storing time is 10-30h, and the re-mixing is thin pass plasticizing 1-10 times.

[0032] Further, the reaction time in step (1) is 1.5h, the reaction pressure is 3.0MPa, and the reaction temperature is 75-85℃.

[0033] The continued reaction time is 10.5h, the reaction pressure is 3.0MPa, and the reaction temperature is 75-85℃.

[0034] The mixing in step (2) is thin pass plasticizing 5 times, the storing time is 16h, and the re-mixing is thin pass plasticizing 5 times.

[0035] The application also provides the use of the above-mentioned fluorine-free surfactant and perfluoroether rubber in preparing rubber materials.

[0036] The application has the following beneficial effects:

[0037] The application provides a fluorine-free surfactant for preparing high-temperature-resistant perfluoroether rubber. The perfluoroether rubber prepared by using the fluorine-free surfactant has excellent mechanical properties and heat aging resistance, and is equivalent to fluorine rubber synthesized by using perfluorooctanoic acid surfactant in performance, and has the potential to replace perfluorooctanoic acid surfactant. The fluorine-free surfactant avoids the harm of traditional fluorine-containing surfactants to the environment and human health; is low in price and easy to industrialize; stable emulsion can be obtained by using high-pressure emulsion polymerization technology, which is conducive to controlling polymerization reaction and has good application prospect.

[0038] Obviously, according to the above content of the application, according to the ordinary technical knowledge and common means in the art, other various forms of modifications, replacements or changes can be made without departing from the above technical idea of the application.

[0039] The above content of the application is further described in detail through the following embodiment. However, it should not be understood that the above subject matter of the application is limited to the following examples. Any technology achieved based on the above content of the application belongs to the scope of the application. DETAILED DESCRIPTION

[0040] The raw materials and equipment used in the application are known products, which are obtained by purchasing commercially available products.

[0041] The parts in this example are all parts by mass.

[0042] In the following experiments, if the temperature is not specified, the reaction is carried out at room temperature, i.e. 25±5°C.

[0043] The preparation process of the fluorine-free surfactant is as follows:

[0044]

[0045] wherein R1 is CH3(CH2) n —, n is an integer of 0-1; R2 is CH3(CH2) m —, m is an integer of 0-3; wherein preferably R1 is CH3— and R2 is CH3(CH2)2—.

[0046] Example 1: Preparation of perfluoro ether rubber raw rubber I

[0047] 1. Preparation of fluorine-free surfactant

[0048] 20 parts of 2-methyl 1-pentanol were added to a reaction kettle, nitrogen was introduced, after the nitrogen was replaced, 120 parts of tetrahydrofuran were added, then 20 parts of sodium hydride were added under stirring and the temperature was controlled at 0-5°C, after 1 h of reaction, 25 parts of 3-chloro 2-hydroxypropane sulfonic acid sodium salt were added, and the reaction was carried out for 24 h under a nitrogen atmosphere. After the reaction was completed, the tetrahydrofuran was distilled off, the obtained product was dissolved in 15 parts of distilled water, and then extracted with 20 parts of petroleum ether. The water phase was subjected to vacuum distillation to obtain the fluorine-free surfactant.

[0049] 2. Preparation of perfluoro ether rubber raw rubber I

[0050] A 30 L reaction vessel was charged with 30 L of deionized water and 900 g of the fluorine-free surfactant from Step 1 in a 50 g / L aqueous solution of the fluorine-free surfactant. The headspace of the reaction vessel was first purged with nitrogen and then with the mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 = 19.8:79.4:0.8, mol%) to an oxygen content of less than 10 ppm. The reaction vessel was heated to 85°C. The mixed monomers were continuously fed into the reaction vessel using a diaphragm compressor to maintain a pressure of 3.0 MPa. The reaction was initiated by adding 600 g of an aqueous initiator solution (50 g / L, initiator is diisopropyl peroxydicarbonate) while stirring the contents of the reaction vessel. The mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 = 19.8:79.4:0.8, mol%) were continuously fed to the reaction vessel to maintain a pressure of 3.0 MPa and a temperature of 75°C. After 1.5 hours of reaction, 75 g of a chain transfer agent, methyl iodide, was added. The reaction was then continued for 12 hours (from the time the initiator was added) until the scheduled amount of 15 kg of mixed monomers was fed. The reaction was then terminated to provide a perfluoroether rubber crude gum I.

[0051] Example 2: Preparation of Perfluoroether Rubber Crude Gum II

[0052] The perfluoroether rubber crude gum II was prepared according to the procedure of Example 1, except that the mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 = 19.8:79.4:0.8, mol%) were replaced with mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 = 10.8:88.4:0.8, mol%).

[0053] Example 3: Preparation of Perfluoroether Rubber Crude Gum III

[0054] The perfluoroether rubber crude gum III was prepared according to the procedure of Example 1, except that the mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 = 19.8:79.4:0.8, mol%) were replaced with mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 = 30.8:68.4:0.8, mol%).

[0055] Example 4: Preparation of Perfluoroether Rubber Crude Gum IV

[0056] The preparation method of Example 1 is referred to, the only difference is that the 50g / L aqueous solution of non-fluorine surfactant containing 900g of non-fluorine surfactant obtained in step 1 is replaced by the 50g / L aqueous solution of non-fluorine surfactant containing 600g of non-fluorine surfactant obtained in step 1; the mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 is 19.8: 79.4: 0.8, mol%) are replaced by mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 is 10.8: 88.4: 0.8, mol%), to obtain perfluoroether rubber raw rubber IV.

[0057] Example 5: Preparation of perfluoroether rubber raw rubber V

[0058] The preparation method of Example 1 is referred to, the only difference is that the 50g / L aqueous solution of non-fluorine surfactant containing 900g of non-fluorine surfactant obtained in step 1 is replaced by the 50g / L aqueous solution of non-fluorine surfactant containing 600g of non-fluorine surfactant obtained in step 1; the mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 is 19.8: 79.4: 0.8, mol%) are replaced by mixed monomers (perfluoromethyl vinyl ether: tetrafluoroethylene: I(CF2)2OCF=CF2 is 10.8: 88.4: 0.8, mol%), to obtain perfluoroether rubber raw rubber IV.

[0059] Example 6: Preparation of perfluoroether rubber I

[0060] 100 parts (mass parts) of perfluoroether rubber raw rubber I obtained in Example 1, 3 parts of vulcanizing agent triallyl isocyanurate TAIC, 1 part of accelerator 2,5-di-tert-butyl peroxy-2,5-dimethyl ethane, 18 parts of filler carbon black N990, and 1 part of internal release agent fluorine-containing polyether derivative (product number: FPA-1, purchased from Solvay (Shanghai) Co., Ltd.) are weighed.

[0061] The weighed perfluoroether rubber raw rubber I is thin-plasticized on a two-roll open mill for 3 times at room temperature. Then the accelerator, the filler, and the internal release agent are mixed and kneaded thoroughly, and then the vulcanizing agent is added and mixed and kneaded thoroughly to obtain a sheet. The mixing operation is: thin-plasticized on a two-roll open mill for 5 times at room temperature. After standing for 16h, the sheet is obtained by re-mixing, to obtain perfluoroether rubber I. The re-mixing operation is: thin-plasticized on a two-roll open mill for 5 times at room temperature.

[0062] Example 7: Preparation of perfluoroether rubber II

[0063] The preparation method of Example 6 is referred to, the only difference is that the perfluoroether rubber raw rubber I is replaced by the perfluoroether rubber raw rubber II obtained in Example 2, to obtain perfluoroether rubber II.

[0064] Example 8: Preparation of perfluoroether rubber III

[0065] The perfluoroether rubber III was prepared according to the preparation method of Example 6, except that the perfluoroether rubber raw rubber I was replaced by the perfluoroether rubber raw rubber III obtained in Example 3.

[0066] Example 9: Preparation of perfluoroether rubber IV

[0067] The high-temperature-resistant perfluoroether rubber IV was prepared according to the preparation method of Example 6, except that the perfluoroether rubber raw rubber I was replaced by the perfluoroether rubber raw rubber IV obtained in Example 4.

[0068] Example 10: Preparation of perfluoroether rubber V

[0069] The perfluoroether rubber V was prepared according to the preparation method of Example 6, except that the perfluoroether rubber raw rubber I was replaced by the perfluoroether rubber raw rubber V obtained in Example 5.

[0070] The following is the preparation method of the control sample.

[0071] Preparation of perfluoroether rubber VI

[0072] 1. Preparation of perfluoroether rubber raw rubber VI: according to the preparation method of Example 2, except that ammonium perfluorooctanoate was used as a surfactant to obtain perfluoroether rubber raw rubber VI.

[0073] 2. Preparation of perfluoroether rubber VI: according to the preparation method of Example 6, except that the perfluoroether rubber raw rubber I was replaced by the perfluoroether rubber raw rubber VI obtained in step 1 to obtain perfluoroether rubber VI.

[0074] The beneficial effects of the present application are demonstrated by the following experimental examples.

[0075] Experimental Example 1: Performance of perfluoroether rubber of the present application

[0076] The perfluoroether rubbers prepared in Examples 6-10 and the control example were tested for performance, and the test method standards are as follows:

[0077] The F content test method standard is BSEN14582-2016.

[0078] The mechanical property test method standard is GB / T30308-2013.

[0079] The compression set test method standard is GB / T30308-2013.

[0080] Table 1 Mechanical properties and heat aging resistance of perfluoroether rubbers of the present application

[0081]

[0082]

[0083] The results are shown in Table 1. Compared with the perfluoroether rubbers prepared in Examples 6-10 of the present invention, the perfluoroether rubber III prepared in Example 8 has excellent mechanical properties and heat aging resistance, which are comparable to those of the comparative example.

[0084] Furthermore, the perfluoroether rubber III prepared in Example 8 and the perfluoroether rubber VI prepared in the comparative example were tested for perfluoroalkyl and polyfluoroalkyl compounds (PFAS) content, and the results are shown in Table 2. Test method: According to standards EN17681-1:2022 and EN17681-2:2022, LC-MS analysis was performed.

[0085] Table 2 Detection of perfluorinated and polyfluorinated alkyl substances (PFAS) content

[0086]

[0087]

[0088]

[0089] Wherein, MDL = method detection limit; ND = not detected (<MDL); “-” = not detected.

[0090] From the PFAS content test results, it can be seen that a high concentration of PFHxA can be extracted from the perfluoroether rubber VI prepared in the comparative example, while the PFHxA content in the perfluoroether rubber III prepared in Example 8 is less than 1 ppm, which is in line with the environmental protection and green concept.

[0091] In summary, the present invention provides a fluorine-free surfactant for preparing high-temperature-resistant perfluoroether rubber. The perfluoroether rubber produced using the fluorine-free surfactant of the present invention exhibits excellent mechanical properties and heat aging resistance, comparable to those of fluororubber synthesized using perfluorooctanoic acid surfactants, and has the potential to replace perfluorooctanoic acid surfactants. The fluorine-free surfactant of the present invention avoids the environmental and human health hazards posed by traditional fluorinated surfactants; it is inexpensive and amenable to industrial production; and it utilizes high-pressure emulsion polymerization technology to produce a stable emulsion, which facilitates the control of the polymerization reaction and has excellent application prospects.

Claims

1. A perfluoroether rubber, characterized in that: The perfluoroether rubber is prepared from perfluoroether rubber raw rubber, a vulcanizing agent, an accelerator, a filler and an internal release agent as raw materials; the mass ratio of the perfluoroether rubber raw rubber, the vulcanizing agent, the accelerator, the filler and the internal release agent is 100:3:1:18:1; The perfluoroether rubber raw rubber is prepared from fluorine-free surfactant, mixed monomer, initiator and chain transfer agent as raw materials, and the mass ratio of the fluorine-free surfactant, mixed monomer, initiator and chain transfer agent is (8-20): 200: 8: 1; The mixed monomers are perfluoromethyl vinyl ether, tetrafluoroethylene and I(CF2)2OCF=CF2, and the molar ratio of perfluoromethyl vinyl ether, tetrafluoroethylene and I(CF2)2OCF=CF2 is (5-50): (50-200): 1; The initiator is at least one of diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, tert-butyl peroxypivalate, and azobisisobutyronitrile; the chain transfer agent is at least one of diiodomethane, 1,2-diiodoethane, perfluorohexyl iodide, perfluorobutyl iodide, and 1,4-diiodooctafluorobutane; The vulcanizing agent is at least one of triallyl isocyanurate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, and m-phenylene bismaleimide; the accelerator is at least one of 2,5-di-tert-butylperoxy-2,5-dimethylethane, diisopropylbenzene peroxide, bis(tert-butylperoxyisopropyl)benzene, and benzoyl peroxide; the filler is carbon black; and the internal release agent is a fluorinated polyether derivative. The fluorine-free surfactant is prepared by the following method: ； Wherein R1 is CH3—, and R2 is CH3(CH2)2—.

2. The perfluoroether rubber according to claim 1, characterized in that: The molar ratio of perfluoromethyl vinyl ether, tetrafluoroethylene and I(CF2)2OCF=CF2 is (13.5-38.5): (85.5-110.5): 1; the initiator is diisopropyl peroxydicarbonate, and the chain transfer agent is diiodomethane; The vulcanizing agent is triallyl isocyanurate, and the accelerator is 2,5-di-tert-butylperoxy-2,5-dimethylethane.

3. The method for preparing the perfluoroether rubber according to claim 1 or 2, characterized in that: The preparation method is as follows: (1) The fluorine-free surfactant, mixed monomer and initiator react, a chain transfer agent is added, and the reaction is continued to obtain perfluoroether rubber raw rubber; The reaction time is 0.5-5 h, the reaction pressure is 1.0-10.0 MPa, and the reaction temperature is 50-120° C. The reaction time is 5 to 20 hours, the reaction pressure is 1.0 to 10.0 MPa, and the reaction temperature is 50 to 120°C. (2) The perfluoroether rubber raw rubber obtained in step (1) is thinly plasticized for 1 to 5 times, an accelerator, a filler, and an internal release agent are added, mixed, and then a vulcanizing agent is added and mixed, aged, and re-mixed to obtain perfluoroether rubber; The mixing is thin-pass mastication for 1 to 10 times, the aging time is 10 to 30 hours, and the re-milling is thin-pass mastication for 1 to 10 times.

4. The preparation method according to claim 3, characterized in that: The reaction time in step (1) is 1.5 h, the reaction pressure is 3.0 MPa, and the reaction temperature is 75-85°C; The reaction time is 10.5 h, the reaction pressure is 3.0 MPa, and the reaction temperature is 75-85°C; The mixing in step (2) is thin-pass plasticizing 5 times, the aging time is 16 hours, and the re-mixing is thin-pass plasticizing 5 times.

5. Use of the perfluoroether rubber according to claim 1 or 2 in the preparation of rubber materials.

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