A siloxane polymer, its preparation method, and its application in the preparation of wide-temperature-range, media-resistant fluorosilicone-fluororubber.

Abstract

A siloxane polymer, its preparation method, and its application in the preparation of wide-temperature-range, media-resistant fluorosilicone-fluororubber are disclosed. The method for preparing the fluorinated polyether-grafted siloxane polymer of this invention includes: a grafting reaction of a perfluoropolyether acyl chloride and a vinyl-terminated fluorosiloxane in the presence of a reaction solvent and an acid-binding agent to obtain the fluorinated polyether-grafted siloxane polymer. The fluorinated polyether-grafted siloxane polymer prepared by this invention can be used as a compatibilizer in the preparation of wide-temperature-range, media-resistant fluorosilicone-fluororubber. While maintaining the good properties of the original silicone rubber or fluororubber, it can also significantly improve the wide-temperature-range, media-resistant properties of the original silicone rubber or fluororubber, greatly expanding the applications of the original rubber.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a siloxane polymer and its preparation method, as well as its application in the preparation of wide-temperature-range, media-resistant fluorosilicone-fluororubber, its preparation method, and its application. Background Technology

[0002] Rubber materials are indispensable basic materials in modern industry, and the rubber products industry is also an important foundational industry for national economic and social development, an integral part of the modern industrial system. Rubber products are not limited to low-requirement equipment operating within a narrow temperature range. In application, rubber materials need to possess high mechanical properties and a wide operating temperature range, capable of withstanding both high and low temperatures without affecting usability. Fluororubber is a synthetic polymer elastomer containing fluorine atoms on the carbon atoms of its main chain or side chains. Its unique chemical structure and high bond energy of the CF bond (485 kJ / mol) contribute to its performance. -1 Fluororubber possesses excellent heat resistance, chemical resistance, and oil resistance. Due to its superior high-temperature resistance, it can be used for extended periods at temperatures up to 250°C or even higher, and for short periods at 300°C. This outstanding high-temperature performance makes it an ideal material for high-temperature environments such as aerospace and automotive manufacturing. Furthermore, fluororubber exhibits excellent oil resistance and chemical resistance, enabling it to operate stably for extended periods in various media such as lubricating oils, hydraulic oils, fuels, concentrated acids, and concentrated oxidants, demonstrating superior stability compared to other synthetic rubbers. However, the relatively rigid molecular chains of fluororubber result in a higher low-temperature brittleness temperature and poor low-temperature performance. In contrast, fluorosilicone rubber possesses unique properties such as high and low temperature resistance, oil resistance, weather resistance, and chemical resistance. Summary of the Invention

[0003] To overcome the problems of long time cycle and high cost in the existing technology, this invention innovatively proposes a preparation method and application of a wide temperature range and medium resistant fluorosilicone-fluororubber. The method uses perfluoropolyether carboxylic acid, trifluoropropylsilane and aminopropylsilane with excellent low temperature resistance as polymer chain segments, and introduces vinyl-containing siloxanes as reactive sites to successfully prepare a graft polymer that can effectively improve the performance of fluorosilicone rubber.

[0004] The technical solution of the present invention is as follows: A method for preparing a fluorinated polyether-grafted siloxane polymer, the method comprising: performing a grafting reaction between a perfluoropolyether acyl chloride and a vinyl-terminated fluorinated siloxane in the presence of a reaction solvent and an acid-binding agent to obtain a fluorinated polyether-grafted siloxane polymer.

[0005] According to an embodiment of the present invention, the reaction solvent is selected from dichloromethane.

[0006] According to an embodiment of the present invention, the acid-binding agent is selected from basic organic reagents, such as triethylamine or pyridine.

[0007] According to an embodiment of the present invention, the conditions for the grafting reaction include: a reaction temperature of -5 to 5°C (0°C) and a reaction time of 1 to 5 hours (e.g., 2 hours).

[0008] According to an embodiment of the present invention, the molar ratio of the perfluoropolyether acyl chloride and the vinyl-terminated fluorosiloxane is 0.9-1.1:0.9-1.1, for example, 1:1.

[0009] According to an embodiment of the present invention, the volume ratio of the sum of the perfluoropolyether acyl chloride and the vinyl-terminated fluorosiloxane, the reaction solvent and the acid-binding agent is 5:1-20:1, for example 5:10:1.

[0010] According to an embodiment of the present invention, the vinyl-terminated fluorosiloxane is prepared by the following steps: (1) The first cyclosiloxane and the second cyclosiloxane are mixed in a molar ratio of 10-30:1 and reacted under the action of a catalyst to obtain a cyclosiloxane compound; (2) After mixing the cyclosiloxane compound, catalyst II, promoter and end-capping agent, react at 80-100℃ (e.g. 95℃) for 1-10h (e.g. 6h) to obtain vinyl-terminated fluorosiloxanes.

[0011] Preferably, the first cyclosiloxane is selected from methyltrifluoropropylcyclosiloxane.

[0012] Preferably, the second cyclosiloxane is obtained by hydrolysis and condensation of an aminopropylsilane coupling agent. Further, the aminopropylsilane coupling agent is selected from at least one of aminopropylmethyldiethoxysilane, aminopropyldimethoxysilane, and N-aminoethyl-3-aminopropylmethyldimethoxysilane. Exemplarily, the second cyclosiloxane is obtained by hydrolysis and condensation of aminopropyldiethoxysilane, for example, methylaminopropylcyclosiloxane.

[0013] Preferably, in step (1), the second cyclosiloxane is obtained by heating an aminosilane coupling agent, deionized water, and catalyst I to 70°C and reacting for 7 hours. After the reaction, water and byproducts (such as ethanol) are removed from the system under negative pressure, and the system is heated to 150°C and reacted for another 2 hours. Further, catalyst I is selected from at least one of tetramethylammonium hydroxide, sodium hydroxide, potassium hydroxide, etc. Further, the mass ratio of aminosilane coupling agent, catalyst I, and deionized water is 400 g: 1-10 g: 100-150 g, for example, 400 g: 5.13 g: 112.86 g.

[0014] Preferably, the aminopropyl content in the cyclosiloxane compound is 1-25%, for example, 5%, 10%, or 20%.

[0015] Preferably, in step (1), the catalyst is selected from at least one of tetramethylammonium hydroxide, sodium hydroxide, potassium hydroxide, etc.

[0016] Preferably, in step (2), catalyst II is selected from, but not limited to, at least one of sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, etc.

[0017] Preferably, in step (2), the accelerator is selected from at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, N,N-dimethylformamide, etc.

[0018] Preferably, in step (2), the capping agent is selected from divinyltetramethyldisiloxane.

[0019] Preferably, in step (2), catalyst II accounts for 1-5‰ of the total mass of the reaction system, for example, 2.5‰.

[0020] Preferably, in step (2), the mass ratio of catalyst II to promoter is 1:2-6, for example, 1:4.

[0021] Preferably, the amount of end-capping agent is 0.0001-0.005 mol / 50g cyclosiloxane compound, then the amount of end-capping agent is 0.0025 mol / 50g cyclosiloxane.

[0022] For example, the vinyl-terminated fluorosiloxane is selected from vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymers, with the following structural formula: Figure 3 As shown.

[0023] According to an embodiment of the present invention, the perfluoropolyether acyl chloride is prepared by using perfluoropolyether carboxylic acid and an acyl chloride reagent. Preferably, the method for preparing perfluoropolyether acyl chloride specifically involves: mixing perfluoropolyether carboxylic acid, dichloromethane, and an acyl chloride catalyst with or without a solvent, then adding the acyl chloride reagent dropwise, and reacting at 35-50°C for a period of time to obtain perfluoropolyether acyl chloride.

[0024] Preferably, the mass ratio of perfluoropolyether carboxylic acid, dichloromethane and acyl chloride catalyst is 1:1:0.01-0.05.

[0025] Preferably, the solvent is selected from solvents known in the art, but the present invention does not impose a specific limitation.

[0026] Preferably, the acyl chloride catalyst is selected from N,N-dimethylformamide.

[0027] Preferably, the acyl chloride reagent is selected from oxalyl chloride.

[0028] According to an exemplary embodiment of the present invention, the fluorinated polyether-grafted siloxane polymer is a vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted with a perfluoropolyether polymer, and its preparation method specifically includes: S1) Preparation of methylaminopropylcyclosiloxane; S2) Methylaminopropylcyclosiloxane and methyltrifluoropropylcyclosiloxane are mixed in a molar ratio of 1:20 and reacted under the action of a catalyst to obtain methyltrifluoropropyl-aminopropylcyclosiloxane. S3) Methyltrifluoropropyl-aminopropylcyclosiloxane, catalyst II, accelerator and end-capping agent are mixed and reacted at 80-100℃ (e.g. 95℃) for 1-10h (e.g. 6h) to obtain vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer. S4) A grafting reaction is carried out between perfluoropolyether acyl chloride and vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer in the presence of a reaction solvent and an acid-binding agent to obtain a vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted with a perfluoropolyether polymer.

[0029] The present invention also provides fluorinated polyether-grafted siloxane polymers obtained by the above preparation method.

[0030] The present invention also provides a fluorosilicone-fluororubber composition, wherein, based on the total mass of the composition, the composition comprises: 20-30 parts by weight of raw fluorosilicone rubber; 20-30 parts by weight of fluorosilicone compound; 0.1-2 parts by weight of crosslinking agent; 0.1-0.5 parts by weight of vulcanizing agent; Compatibilizer; The compatibilizer is selected from the above-mentioned fluorinated polyether-grafted siloxane polymer, and the compatibilizer accounts for 1-10% of the total mass of the composition.

[0031] According to an embodiment of the present invention, the fluorosilicone rubber raw material is selected from fluorosilicone rubber raw materials known in the art, for example, DAI EL, purchased from Daikin Fluorochemicals (China) Co., Ltd. TM G-902.

[0032] According to an embodiment of the present invention, the fluorosilicone compound is selected from fluorosilicone compounds known in the art, such as those purchased from Shenzhen Guanheng New Material Technology Co., Ltd., grade AFS-R-R1070 (24-SO-675).

[0033] According to an embodiment of the present invention, the compatibilizer is, for example, selected from a vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted with a perfluoropolyether polymer.

[0034] According to an embodiment of the present invention, the crosslinking agent is selected from crosslinking agents known in the art, such as triallyl isocyanurate (TAIC).

[0035] According to an embodiment of the present invention, the vulcanizing agent is selected from vulcanizing agents known in the art, such as bis(2,5)-pentasulfide.

[0036] According to an embodiment of the present invention, the fluorosilicone rubber raw material is 20 parts by weight, 25 parts by weight, or 30 parts by weight, based on the total mass of the composition.

[0037] According to an embodiment of the present invention, the fluorosilicone compound is 20 parts by weight, 25 parts by weight, or 30 parts by weight, based on the total mass of the composition.

[0038] According to an embodiment of the present invention, the compatibilizer is 1%, 2%, 4%, 6%, 8%, 10% or any two of the above values, based on the total mass of the composition.

[0039] According to an embodiment of the present invention, the crosslinking agent is 0.1 parts by mass, 0.5 parts by mass, 1 part by mass, 1.5 parts by mass, or 2 parts by mass, based on the total mass of the composition.

[0040] According to an embodiment of the present invention, the vulcanizing agent is 0.1 parts by mass, 0.2 parts by mass, 0.3 parts by mass, 0.4 parts by mass, and 0.5 parts by mass, based on the total mass of the composition.

[0041] The present invention also provides a fluorosilicone-fluororubber, the raw materials of which include the above-mentioned fluorosilicone-fluororubber composition.

[0042] According to an embodiment of the present invention, the fluorosilicone-fluororubber has at least one of the following properties: 1) Tensile strength is 8~11MPa, for example, 10.72MPa, 8.48MPa, 8.5MPa; 2) Elongation at break is 200-300%, for example, 283.25%, 231.11%, 237.34%; 3) The 100% constant tensile stress is 1-5 MPa, for example, 4.63 MPa, 4.43 MPa, 3.96 MPa; 4) Tanδ ranges from -55 to -48.5, for example, -52, -50.7, -47.8, -47.5, and -48.5; 5) Tear strength is 10~20 kN.m -1 For example, 15.43 kN.m -1 13.39 kN.m -1 13.83 kN.m -1 .

[0043] Tanδ is the DMA loss factor, which can be further used to characterize the glass transition temperature of the material.

[0044] According to an embodiment of the present invention, the fluorosilicone-fluororubber retains more than 80% of its tensile strength after high-temperature aging. In this invention, the tensile strength retention rate refers to the ratio of the tensile strength after the oil resistance test to the tensile strength before the oil resistance test.

[0045] The present invention also provides a method for preparing the above-mentioned fluorosilicone-fluororubber, the method comprising: adding each component of the fluorosilicone-fluororubber composition into a mixer for mixing, and performing a first-stage vulcanization and a second-stage vulcanization in sequence to obtain the fluorosilicone-fluororubber.

[0046] According to an embodiment of the present invention, the mixing temperature is selected from 50-100°C, for example, 80°C.

[0047] According to an embodiment of the present invention, the components of the fluorosilicone-fluororubber composition can be added together or separately to a mixer; when the components are added separately, the order of addition is as follows: fluororubber, fluorosilicone, then compatibilizer and crosslinking agent, and finally vulcanizing agent; after each substance is added, it can be mixed for 1 to 10 minutes before adding other substances.

[0048] According to an embodiment of the present invention, the temperature of the first vulcanization stage is 160~180℃, the pressure is 5~20MPa, and the vulcanization time is 10~30min, for example, 15min.

[0049] According to an embodiment of the present invention, the temperature of the two-stage vulcanization is 180~220℃, and the vulcanization time is 0.1~5h, for example, 2h.

[0050] The present invention also provides applications of the above-mentioned fluorosilicone-fluororubber, for example, in the preparation of different types of silicone rubber and / or fluororubber.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows: The fluorinated polyether-grafted siloxane polymer prepared by this invention can be used as a compatibilizer to prepare wide-temperature-range, medium-resistant fluorosilicone-fluororubber.

[0052] The fluorosilicone-fluororubber prepared using this invention retains the good properties of virgin silicone rubber or fluororubber while significantly improving their performance over a wide temperature range and in resistance to various media, greatly expanding the applications of virgin rubber. Furthermore, this invention can significantly reduce production costs and improve production efficiency in practical applications, demonstrating promising application prospects. Attached Figure Description

[0053] Figure 1This is the structural formula of Example 1.

[0054] Figure 2 As in Example 1 1 H NMR spectrum.

[0055] Figure 3 This is the structural formula for Example 3.

[0056] Figure 4 Example 3 1 1H NMR spectrum and magnified view of the 5.5-6.6 ppm range.

[0057] Figure 5 The mechanical properties and stress-strain diagrams after aging of Comparative Example 1, Comparative Example 2, Example 5, Example 6, and Example 7 are shown. Detailed Implementation

[0058] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0059] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0060] KH-902: γ-aminopropylmethyldiethoxysilane, purchased from Beijing Innocare Technology Co., Ltd.

[0061] TAIC: Triallyl isocyanurate, purchased from Beijing Innocare Technology Co., Ltd.

[0062] Double 25: Purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0063] Example 1 Preparation of methylaminopropylcyclosiloxane The aminosilane coupling agent KH-902 (400 g, 2.09 mol), deionized water (112.86 g, 6.27 mol), and the catalyst tetramethylammonium hydroxide (5.13 g) were added to a three-necked flask equipped with a stirrer. The mixture was stirred and gradually heated to 70°C for 7 hours. After the reaction was completed, water and the byproduct ethanol were removed from the system under negative pressure. The heating system was then raised to 150°C and the reaction continued for 2 hours to decompose the catalyst tetramethylammonium hydroxide and remove low-boiling-point compounds. After cooling to room temperature, a viscous and transparent product was obtained, which is the methylaminopropyl cyclic 1 synthesized in this example, with the following structural formula: Figure 1 As shown.

[0064] The 1H NMR spectrum of the cyclic polymer 1 synthesized in this embodiment is as follows: Figure 2 As shown, the chemical shifts at 0-0.15 ppm are attributed to characteristic peaks of H on Si-CH3, at 0.4-0.58 ppm to characteristic peaks of H on Si-CH2-, at 1.02-1.95 ppm to characteristic peaks of H on C-CH2-C and -NH2, and at 2.58-2.74 ppm to characteristic peaks of H on C-CH2-N. Meanwhile, no characteristic peaks of hydroxyl groups were detected in the 1H NMR spectrum. The 1H NMR results indicate that the methylaminopropylcyclosiloxane obtained in this embodiment possesses the following characteristics: Figure 1 The structure shown.

[0065] Example 2 Preparation of methyltrifluoropropyl-aminopropylcyclosiloxane 50 g (0.1067 mol) of methyltrifluoropropylcyclosiloxane, 2.82 g (0.00534 mol), 5.63 g (0.01067 mol), and 2.82 g (0.02134 mol) of methylaminopropylcyclosiloxane from Example 1, and 1% (by mass) of tetramethylammonium hydroxide catalyst were added to a three-necked flask equipped with a stirrer. The mixture was stirred and gradually heated to 95°C and reacted for 6 h. After the reaction was completed, the heating system was raised to 150°C under negative pressure and maintained at this temperature for at least 30 min to decompose the catalyst and low-boiling compounds in the system. The system was then cooled to room temperature to obtain a transparent and viscous product, thus preparing methyltrifluoropropyl-aminopropylcyclosiloxanes with aminopropyl content of 5%, 10%, and 20%, respectively.

[0066] Example 3 Preparation of vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer 50g of methyltrifluoropropyl-aminopropylcyclosiloxane prepared in Example 2 with aminopropyl content of 5%, 10%, and 20% were added to a three-necked flask equipped with a stirrer, along with 2.5‰ of the total raw material mass of tetramethylammonium hydroxide catalyst, four times the mass of catalyst promoter ethylene glycol dimethyl ether, and 0.466g of end-capping agent divinyltetramethyldisiloxane. The mixture was stirred and gradually heated to 95°C for 6 hours. After the reaction was completed, the promoter was removed from the system under negative pressure. The system was then heated to 150°C and maintained at this temperature for at least 30 minutes to decompose the catalyst and low-boiling compounds. The system was cooled to room temperature to obtain a transparent and viscous product, which is the vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer synthesized in this example. Its structural formula is as follows: Figure 3 As shown.

[0067] The 1H NMR spectrum of the vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer synthesized in this embodiment is as follows: Figure 4 As shown, the chemical shifts at 0.05-0.25 ppm are attributed to the characteristic peaks of H on Si-CH3, at 0.48-0.57 ppm to the characteristic peaks of H on Si-CH2- in aminopropyl, at 0.68-0.83 ppm to the characteristic peaks of H on Si-CH2- in trifluoropropyl, at 1.37-1.78 ppm to the characteristic peaks of H on C-CH2-C and -NH2, at 1.93-2.18 ppm to the characteristic peaks of H on C-CH2-C in trifluoropropyl, at 2.61-2.72 ppm to the characteristic peaks of H on C-CH2-N, and at 5.68-6.15 ppm to the characteristic peaks of H on -CH=CH2. The 1H NMR spectrum results indicate that the vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer obtained in this embodiment possesses the following characteristics: Figure 3 The structure shown.

[0068] Example 4 Preparation of vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted onto perfluoropolyether polymer (1) Acyl chloride of perfluoropolyether carboxylic acid 50 g (0.0167 mol) of perfluoropolyether carboxylic acid, an equal mass of dichloromethane, and approximately 0.5 g of N,N-dimethylformamide (an acyl chloride catalyst) were added to a two-necked flask equipped with a magnetic stirrer. The mixture was stirred thoroughly under reflux using a magnetic stirrer, while oxalyl chloride (approximately 5 mL) was slowly added dropwise through a constant-pressure dropping funnel. The reaction temperature was maintained at approximately 45°C. After several hours of reaction, a sample was taken to determine if the perfluoropolyether carboxylic acid had completely participated in the reaction. After the reaction was complete, the solvent and unreacted residual oxalyl chloride were removed by rotary evaporation to obtain the activated perfluoropolyether acyl chloride.

[0069] (2) Preparation of grafted polymers Perfluoropolyether acyl chloride, dichloromethane, and triethylamine were added to a two-necked flask equipped with a stirrer and stirred until homogeneous under ice bath conditions. Simultaneously, the terminal vinyl polymethyltrifluoropropyl-aminopropylsiloxane prepared in Example 3 was slowly added dropwise through a constant-pressure dropping funnel, maintaining the reaction temperature at 0°C. The molar ratio of the acyl chloride in the perfluoropolyether acyl chloride to the amino group in the terminal vinyl polymethyltrifluoropropyl-aminopropylsiloxane was 1:1, and the volume ratio of perfluoropolyether acyl chloride to terminal vinyl polymethyltrifluoropropyl-aminopropylsiloxane:dichloromethane:triethylamine was 5:10:1. After the addition was complete, the ice bath was removed, and the reaction was continued to be stirred at room temperature for 2 hours. After the reaction was completed, the lower precipitate was separated using a separatory funnel, and the solvent in the system was removed by rotary evaporation to obtain the grafted polymer, which is the terminal vinyl polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted onto the perfluoropolyether polymer, and used as a compatibilizer.

[0070] Example 5 Preparation and performance determination of wide-temperature-range, media-resistant fluorosilicone-fluororubber: Heat the internal mixer to about 80°C, add raw fluorosilicone rubber (purchased from Daikin Fluorochemicals (China) Co., Ltd.; brand: G-902) and masticate for 3-5 minutes. Then add fluorosilicone compound (purchased from Shenzhen Guanheng New Material Technology Co., Ltd., AFS-R-R1070(24-SO-675)) and mix. Then add 2 wt% of the total mass of the vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted perfluoropolyether polymer (compensator) and crosslinking agent TAIC (tracelyl isocyanurate) prepared in Example 4 and continue mixing for 8-10 minutes. Add bis(2,5-dimethyl)sulfonate as a vulcanizing agent and continue masticating for 3-5 minutes until the vulcanizing agent and the blended compound are evenly mixed. The amounts of each raw material are as follows: 25g fluororubber, 25g fluorosilicone compound, 1g compatibilizer (Example 4), 1g crosslinking agent, and 0.4g vulcanizing agent.

[0071] The sample was vulcanized in one stage using a flat vulcanizing machine under the following conditions: 10 MPa, 170 °C, 15 min. A second stage of vulcanization was then carried out in a forced-air drying oven under the following conditions: 200 °C, 2 h; thus, fluorosilicone-fluororubber was prepared.

[0072] The mechanical properties, DMA loss factor Tanδ, aging resistance and oil resistance of the fluorosilicone-fluororubber prepared above were tested according to the methods of GB / T528-2009, GB / T40396-2021, GB / T1960-2010 and GB / T3512-2014.

[0073] Example 6 The preparation and performance testing of wide-temperature-range, media-resistant fluorosilicone-fluororubber are basically the same as in Example 5, except that: Add 4 wt% of the total mass of the vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted with perfluoropolyether polymer prepared in Example 4 to the compound rubber, and the remaining conditions are the same as in Example 5.

[0074] Example 7 The preparation and performance testing of wide-temperature-range, media-resistant fluorosilicone-fluororubber are basically the same as in Example 5, except that: Add 6 wt% of the total mass of the vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted with perfluoropolyether polymer prepared in Example 4 to the compound rubber, and the remaining conditions are the same as in Example 5.

[0075] Comparative Example 1 Comparison of fluororubber sample preparation: The raw fluorosilicone rubber (purchased from Daikin Fluorochemicals (China) Co., Ltd.) was DAI EL TM G-902) and fluorosilicone compound (purchased from Shenzhen Guanheng New Material Technology Co., Ltd.; brand: AFS-R-H1030(24-JS-07)) were added to a mixer and plasticized for 8-10 minutes. Then, bis(2,5)5 was added as a vulcanizing agent and plasticized for another 3-5 minutes until the vulcanizing agent and the compound were mixed evenly. The amount of each raw material was the same as in Example 5.

[0076] The sample was vulcanized in one stage using a flat vulcanizing machine under the following conditions: 10 MPa, 170℃, 10 min. A second stage of vulcanization was then performed in a forced-air drying oven under the following conditions: 200℃, 2 h; this yielded a control fluororubber.

[0077] The mechanical properties, DMA, aging resistance and oil resistance of the comparative fluororubber prepared above were tested according to the methods of GB / T528-2009, GB / T40396-2021, GB / T1960-2010 and GB / T3512-2014.

[0078] Comparative Example 2 Heat the internal mixer to approximately 80°C, then add raw fluorosilicone rubber (purchased from Daikin Fluorochemicals (China) Co., Ltd.). TM After plasticizing G-902 for 3-5 minutes, add fluorosilicone compound (purchased from Shenzhen Guanheng New Material Technology Co., Ltd., AFS-R-R1070(24-SO-675)) and TAIC and mix for 8-10 minutes. Add bis(2,5) as a vulcanizing agent and continue plasticizing for 3-5 minutes until the vulcanizing agent and the compound are evenly mixed. The amount of each raw material is the same as in Example 5.

[0079] The sample underwent a first-stage vulcanization using a flat vulcanizing machine under the following conditions: 10 MPa, 170℃, 15 min. A second-stage vulcanization was then performed in a forced-air drying oven under the following conditions: 200℃, 2 h.

[0080] The mechanical properties, DMA, aging resistance and oil resistance of the blended adhesive prepared above were tested according to the methods of GB / T528-2009, GB / T40396-2021, GB / T1960-2010 and GB / T3512-2014.

[0081] The test results of Examples 4-6 and the comparative examples are recorded in Table 1.

[0082] Table 1. Results of the study on the physicochemical properties of the fluororubber compound of the present invention

[0083] Tensile retention rate refers to the change in tensile strength before and after the oil resistance test. The fracture retention rate refers to the change in elongation at break before and after the oil resistance test. Δm refers to the change in mass before and after the oil resistance test.

[0084] According to the results in Table 1 above, the fluorosilicone / fluororubber compounds prepared in Examples 5-7 simultaneously exhibit good mechanical properties, aging resistance, and oil resistance. Compared with the fluorosilicone rubber prepared in the comparative examples and the compound without compatibilizer, the fluorosilicone / fluororubber compounds prepared in Examples 5-7, while achieving similar or better mechanical properties, show significantly improved aging resistance and oil resistance, indicating that the modified fluorosilicone / fluororubber has significantly improved resistance to media. The fluorosilicone / fluororubber prepared by this invention not only increases the mechanical properties of fluorosilicone rubber but also significantly improves its resistance to media, which is beneficial for expanding the application range of the original fluorosilicone rubber. Furthermore, this invention can greatly reduce production costs and improve production efficiency in practical applications, demonstrating promising application prospects.

[0085] The exemplary embodiments of the present invention have been described above. However, the scope of protection of this application is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for the preparation of a fluorine-containing polyether grafted siloxane polymer, characterized in that, The preparation method includes: grafting perfluoropolyether acyl chloride and vinyl-terminated fluorosiloxane in the presence of a reaction solvent and an acid-binding agent to obtain a fluorinated polyether-grafted siloxane polymer.

2. The production method according to claim 1, characterized by, The reaction solvent is selected from dichloromethane; The acid-binding agent is selected from alkaline organic reagents; The conditions for the grafting reaction include: a reaction temperature of -5 to 5°C and a reaction time of 1 to 5 hours. The molar ratio of the perfluoropolyether acyl chloride and the vinyl-terminated fluorosiloxane is 0.9-1.1:0.9-1.1; The volume ratio of the perfluoropolyether acyl chloride and the vinyl-terminated fluorosiloxane, the reaction solvent, and the acid-binding agent is 5:1 to 20:

1.

3. The production method according to claim 1 or 2, characterized by, The vinyl-terminated fluorosiloxanes are prepared by the following steps: (1) The first cyclosiloxane and the second cyclosiloxane are mixed in a molar ratio of 10-30:1 and reacted under the action of a catalyst to obtain a cyclosiloxane compound; (2) After mixing the cyclosiloxane compound, catalyst II, promoter and end-capping agent, react at 80-100℃ for 1-10h to obtain vinyl-terminated fluorosiloxanes; The first cyclosiloxane is selected from methyltrifluoropropylcyclosiloxane; The second cyclosiloxane is obtained by hydrolysis and condensation of an aminopropylsilane coupling agent; the aminopropylsilane coupling agent is selected from at least one of aminopropylmethyldiethoxysilane, aminopropyldimethoxysilane, and N-aminoethyl-3-aminopropylmethyldimethoxysilane.

4. The production method according to claim 3, characterized by, In step (1), the second cyclosiloxane is obtained by heating aminosilane coupling agent, deionized water, and catalyst I to 70°C for 7 hours, removing water and byproducts from the system under negative pressure after the reaction, and then heating the system to 150°C to continue the reaction for 2 hours. Catalyst I is selected from at least one of tetramethylammonium hydroxide, sodium hydroxide, and potassium hydroxide; The mass ratio of aminosilane coupling agent, catalyst I, and deionized water is 400 g: 1-10 g: 100-150 g; The cyclosiloxane compound contains 1-25% aminopropyl groups. In step (1), the catalyst is selected from at least one of tetramethylammonium hydroxide, sodium hydroxide, and potassium hydroxide; In step (2), catalyst II is selected from, but not limited to, at least one of sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide; In step (2), the accelerator is selected from at least one of ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and N,N-dimethylformamide; In step (2), the capping agent is selected from divinyltetramethyldisiloxane; In step (2), catalyst II accounts for 1-5‰ of the total mass of the reaction system; In step (2), the mass ratio of catalyst II to promoter is 1:2-6.

5. The method of any one of claims 1-4, wherein, The perfluoropolyether acyl chloride is prepared by perfluoropolyether carboxylic acid and acyl chloride reagent. The specific method for preparing perfluoropolyether acyl chloride is as follows: after mixing perfluoropolyether carboxylic acid, dichloromethane and acyl chloride catalyst with optional solvent, acyl chloride reagent is added dropwise and reacted at 35-50℃ for a period of time to obtain perfluoropolyether acyl chloride. The mass ratio of perfluoropolyether carboxylic acid, dichloromethane, and acyl chloride catalyst is 1:1:0.01-0.01; The acyl chloride catalyst is selected from N,N-dimethylformamide; The acyl chloride reagent is selected from oxalyl chloride.

6. A fluorinated polyether-grafted siloxane polymer obtained by the preparation method according to any one of claims 1-6.

7. A fluoro-silicone-fluoroelastomer composition characterized in that, The composition comprises, by total mass of the composition: 20-30 parts by weight of raw fluorosilicone rubber; 20-30 parts by weight of fluorosilicone compound; 0.1-2 parts by weight of crosslinking agent; 0.1-0.5 parts by weight of vulcanizing agent; Compatibilizer; The compatibilizer is selected from the fluorinated polyether-grafted siloxane polymer of claim 6, and the compatibilizer accounts for 1-10% of the total mass of the composition. Preferably, the compatibilizer is selected from a vinyl-terminated polymethyltrifluoropropyl-aminopropylsiloxane polymer grafted with a perfluoropolyether polymer; The crosslinking agent is triallyl isocyanurate; The vulcanizing agent is selected from bis(2,5) vulcanizing agent.

8. A fluorosilicone-fluororubber, wherein the raw materials include the fluorosilicone-fluororubber composition of claim 7; Preferably, the fluorosilicone-fluororubber has at least one of the following properties: 1) Tensile strength is 8~11 MPa; 2) Elongation at break is 200-300%; 3) The 100% constant tensile stress is 1-5 MPa; 4) Tanδ ranges from -55 to -48.

5. 5) tear strength of 10-20 kN.m -1 ; The fluorosilicone-fluororubber retains more than 80% of its tensile strength after high-temperature aging.

9. The method of producing a fluoro-silicone-fluoroelastomer according to claim 8, characterized in that, The preparation method includes: adding each component of the fluorosilicone-fluororubber composition into a mixer for mixing, and then performing a first-stage vulcanization and a second-stage vulcanization to obtain the fluorosilicone-fluororubber; Preferably, the mixing temperature is selected from 50-100℃; Preferably, the components of the fluorosilicone-fluororubber composition are added together or separately to a mixer; when the components are added separately, the order of addition is as follows: fluororubber, fluorosilicone, then compatibilizer and crosslinking agent, and finally vulcanizing agent; after each substance is added, the mixture is mixed for 1 to 10 minutes before adding other substances. Preferably, the temperature of the first-stage vulcanization is 160~180℃, the pressure is 5~20MPa, and the vulcanization time is 10~30min; Preferably, the temperature for the second-stage vulcanization is 180~220℃, and the vulcanization time is 0.1~5h.

10. The use of the fluorosilicone-fluororubber of claim 8 in the preparation of silicone rubber and / or fluororubber.

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