Vinyl fluorosilicone and method for preparing the same

Abstract

This invention discloses vinyl fluorinated polysiloxanes and their preparation methods, relating to the field of organosilicon materials technology. The invention utilizes highly active fluorinated potassium hydroxide silanolate as a catalyst for efficient catalysis; it introduces deionized water as a retarder for the first time, using D3F as the main monomer and D3Vi as the comonomer, effectively inhibiting rapid polymerization; and it employs vinyldimethylethoxysilane as a capping agent for the first time, simultaneously achieving end-group vinylization to obtain divinyl polysiloxanes with both end groups and side chains. Through the synergistic combination of ring-opening polymerization and condensation polymerization, the reaction process is mild and controllable, the product viscosity is controllable, and the crosslinking activity is strong, significantly broadening the application range.

Description

Technical Field

[0001] This invention relates to the field of organosilicon materials technology, specifically to vinyl fluorinated polysiloxanes and their preparation methods. Background Technology

[0002] Vinyl fluorinated polysiloxanes are a class of high-performance materials with excellent resistance to high and low temperatures, oil, solvents, and low surface energy. Fluorosilicone liquid silicone rubber prepared using these as a base adhesive has a wider processing window, allowing for precise filling of complex mold cavities. It does not release any byproducts during curing, making it environmentally friendly and indispensable as a key material in the aerospace and high-end equipment industries. The global market size is projected to grow at an average annual rate of 8-10%, particularly in emerging fields such as 5G communications, new energy vehicles, and high-end medical equipment, where the demand for high-performance fluorosilicone materials is increasing daily.

[0003] Traditional methods for preparing vinyl fluorinated polysiloxanes typically employ acidic or alkaline catalysts, such as sulfuric acid and lithium hydroxide. However, these catalysts suffer from drawbacks including harsh reaction conditions, numerous side reactions, low product purity, low yield, and difficulty in controlling molecular weight. The potassium hydroxide silanolate catalytic system combines the high activity of traditional alkaline catalysis with the stability of silanolates, effectively solving the catalyst water absorption problem and improving the controllability of the polymerization reaction. Chinese invention patent CN105778104A discloses an addition-type liquid fluorosilicone rubber base and its preparation method, using potassium hydroxide or sodium hydroxide silanolate as a catalyst. However, due to the poor solubility of ordinary methylsilanolates with trifluoropropylmethylcyclotrisiloxane (D3F), their catalytic activity is reduced, requiring higher temperatures for catalysis. Furthermore, high-temperature catalysis easily leads to ring-opening and reversion of D3F, reducing product yield.

[0004] Furthermore, existing technologies often use chlorosilane monomers as raw materials, which easily generate corrosive byproducts, increasing the difficulty and cost of post-processing. Ring-opening polymerization of cyclic siloxanes is an important route for preparing high-performance polysiloxanes, especially D3F polymers, which possess excellent heat resistance, chemical resistance, and low surface energy. Introducing vinyl functional groups can further enhance the crosslinking ability and mechanical properties of the material, expanding its applications in high-end sealing materials, electronic packaging, and special coatings.

[0005] Chinese invention patent CN103642046A discloses a method for preparing vinyl-terminated fluorosilicone oil. The method involves mixing hydroxyl-terminated fluorosilicone oil or an acetone solution of hydroxyl-terminated fluorosilicone oil with (N,N-dialkylamino)dimethylvinylsilane, stirring at 20-120°C for 2-24 hours, removing the solvent and residual small molecules by vacuum distillation, and obtaining the vinyl-terminated fluorosilicone oil after cooling. This method uses acetone as a solvent, which produces an irritating and harmful odor, and the capped vinyl chains are directly linked to trifluoropropyl chains, resulting in low crosslinking activity.

[0006] Chinese invention patent CN105778104A discloses an addition-type liquid fluorosilicone rubber base and its preparation method, and Chinese invention patent CN115772265A discloses a vinyl fluorinated polysiloxane and its preparation method, which respectively use 1-vinyl-3-hydroxy-1,1,3,3-tetramethyldisiloxane end-capping agent and hydroxyl-terminated trifluoropropylmethyl polysiloxane. The two raw materials are expensive and difficult to achieve large-scale industrial production, resulting in poor universality. Summary of the Invention

[0007] To address the shortcomings of current methods for preparing vinyl fluorinated polysiloxanes, such as poor controllability, high cost, and non-environmentally friendly reaction conditions, this invention provides a vinyl fluorinated polysiloxane with mild reaction conditions and controllable product viscosity, as well as its preparation method. Using fluorinated potassium hydroxide silanolate as a catalyst, D3F as the main polymerizing monomer, D3Vi as the secondary polymerizing monomer, deionized water as a retarder, and vinyl dimethyl ethoxysilane as a capping agent, vinyl fluorinated polysiloxane is prepared through a combination of ring-opening polymerization and condensation polymerization.

[0008] The technical solution of this invention is as follows:

[0009] On one hand, the present invention provides a method for preparing vinyl-containing fluorinated polysiloxanes, comprising the following steps:

[0010] S1 mixes trifluoropropylmethylcyclotrisiloxane and trivinyltrimethylcyclotrisiloxane (D3Vi), heats to 70-80°C, evacuates, and introduces nitrogen gas for dehydration;

[0011] S2 is heated to 100-140℃, and the catalyst containing fluorine-containing potassium hydroxide silanol salt and the retarder deionized water are added. The mixture is stirred and reacted for 3-5 hours.

[0012] S3 is cooled to 70-80℃ and subjected to a dehydration condensation reaction under vacuum for 2-3 hours.

[0013] S4 was restored to normal pressure and temperature was maintained. The end-capping agent vinyldimethylethoxysilane was added and the reaction was stirred for 2-3 hours. Then, the terminator fluorosilicone phosphate was added and the reaction was continued for 2-3 hours while maintaining a vacuum of -40 to -30 kPa.

[0014] S5 is heated to 170-180℃, evacuated to -100~-90kPa, and nitrogen is introduced to remove low molecular weight compounds, thus obtaining vinyl fluorinated polysiloxane.

[0015] The structural formula of D3F is as follows:

[0016] .

[0017] The structural formula for D3Vi is as follows:

[0018] .

[0019] The structural formula of the end-capping agent vinyldimethylethoxysilane is as follows:

[0020] .

[0021] Preferably, the mass ratio of trifluoropropylmethylcyclotrisiloxane, trivinyltrimethylcyclotrisiloxane to the end-capping agent vinyldimethylethoxysilane is 100:(8.5-18.5):(0.4-0.5).

[0022] Preferably, in step S1, the vacuum is drawn to -20~-10kPa and dehydrated for 1-2 hours.

[0023] Preferably, the mass ratio of the total mass of trifluoropropylmethylcyclotrisiloxane, trivinyltrimethylcyclotrisiloxane and the end-capping agent to the mass ratio of the catalyst and the retarder is 100: (0.01-0.16): (0.005-0.3).

[0024] Preferably, in step S2, the catalyst fluorine-containing potassium hydroxide silanolate is prepared by mixing trifluoropropylmethylcyclotrisiloxane and divinyltetramethyldisiloxane (DVTMDS) and heating to 160-170°C, adding potassium hydroxide under stirring, and continuously purging nitrogen gas during the reaction; after reacting for 7-8 hours, a fluorine-containing potassium hydroxide silanolate solution with an alkali content (i.e., potassium hydroxide content) of 4-6 wt.% is obtained.

[0025] Preferably, the mass ratio of trifluoropropylmethylcyclotrisiloxane, divinyltetramethyldisiloxane to potassium hydroxide is 100:(55-65):(6.5-10).

[0026] Preferably, in step S4, the mass ratio of the terminator to the catalyst is (1.5-2):1.

[0027] Preferably, in step S4, the method for preparing the terminating agent fluorosilicic phosphate is as follows: trifluoropropylmethylcyclotrisiloxane, divinyltetramethyldisiloxane and phosphoric acid are mixed and heated to 160-170°C, and reacted under stirring conditions for 7-8 hours; nitrogen gas is continuously introduced during the reaction and the generated water is separated to obtain a fluorosilicic phosphate with an acid content (i.e., phosphoric acid content) of 4-6 wt.%.

[0028] Preferably, the mass ratio of trifluoropropylmethylcyclotrisiloxane, divinyltetramethyldisiloxane to phosphoric acid is 100:(5-15):(4.2-7).

[0029] On the other hand, the present invention provides a vinyl-containing fluorinated polysiloxane, prepared by the above-described method for preparing vinyl-containing fluorinated polysiloxanes. It has the following general structural formula:

[0030] .

[0031] In the formula, m is an integer between 100 and 500, and n is an integer between 50 and 150.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. This invention uses fluorinated potassium hydroxide silanolysate as a catalyst, which has the advantages of mild reaction conditions, higher catalytic activity and no odor or harmful gas generation compared with the polyphosphazene chloride or tetramethylammonium hydroxide used in existing preparation methods; compared with conventional methyl potassium hydroxide silanolysate, it has the advantages of better compatibility, higher catalytic activity and more transparent product appearance, and meets the conditions for low-temperature polymerization.

[0034] 2. This invention introduces deionized water as a polymerization retarder for the first time, effectively suppressing the rapid polymerization of the ring-opening reaction and resulting in a more uniform molecular weight distribution. Simultaneously, this invention uses vinyldimethylethoxysilane as a capping agent for the first time, enabling simultaneous vinylation of the end groups and preparing polysiloxanes containing vinyl groups in both the end groups and side chains. This overcomes the limitation of existing technologies that can only prepare side-chain vinyl products, significantly improving crosslinking activity and application range.

[0035] 3. This invention combines ring-opening polymerization and condensation polymerization in a synergistic manner, resulting in a milder reaction process with greater controllability. This avoids the problem of uneven molecular weight distribution that may result from simply performing dehydration condensation reactions in existing technologies.

[0036] 4. The preparation method of the present invention is simple and environmentally friendly, and the prepared vinyl fluorinated polysiloxane has both precise viscosity control and a higher degree of vinyl functionalization (the end group and side chain contain vinyl groups at the same time). Attached Figure Description

[0037] Figure 1 It is the vinyl fluorinated polysiloxane prepared in Example 1 of this invention. 1 HNMR spectrum.

[0038] Figure 2 This is the infrared spectrum of the vinyl fluorinated polysiloxane prepared in Example 1 of this invention.

[0039] Figure 3 It is the vinyl fluorinated polysiloxane prepared in Example 2 of this invention. 1 HNMR spectrum.

[0040] Figure 4 It is the vinyl fluorinated polysiloxane prepared in Example 3 of this invention. 1 HNMR spectrum. Detailed Implementation

[0041] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0042] I. Catalyst Preparation

[0043] (1) Preparation of catalyst 1

[0044] 312g of D3F and 186g of DVTMDS were added to a reaction flask, and a reaction apparatus equipped with a reflux condenser and a water separator was installed. DVTMDS was added to the water separator until the liquid level touched the inner edge of the wall. The system temperature was set to 160℃ and heating was started. 28g of potassium hydroxide was added under stirring. During the reaction, the gas delivery tube was inserted below the liquid surface, and nitrogen gas was continuously introduced for protection. After 8 hours of reaction, a colorless, transparent, fluorinated potassium hydroxide silanolate solution with an alkali content of 5 wt.% was obtained and stored for later use.

[0045] (2) Preparation of catalyst 2

[0046] 300g of D3F and 165g of DVTMDS were added to a reaction flask, and a reaction apparatus equipped with a reflux condenser and a water separator was installed. DVTMDS was added to the water separator until the liquid level touched the inner edge of the wall. The system temperature was set to 165℃ and heating was started. 20g of potassium hydroxide was added under stirring. During the reaction, the gas delivery tube was inserted below the liquid surface, and nitrogen gas was continuously introduced for protection. After 7 hours of reaction, a colorless, transparent, fluorinated potassium hydroxide silanolate solution with an alkali content of 4 wt.% was obtained and stored for later use.

[0047] (3) Preparation of catalyst 3

[0048] 310g of D3F and 195g of DVTMDS were added to a reaction flask, and a reaction apparatus equipped with a reflux condenser and a water separator was installed. DVTMDS was added to the water separator until the liquid level touched the inner edge of the wall. The system temperature was set to 170℃ and heating was started. 30g of potassium hydroxide was added under stirring. During the reaction, the gas delivery tube was inserted below the liquid surface, and nitrogen gas was continuously introduced for protection. After 7.5 hours of reaction, a colorless, transparent, fluorinated potassium hydroxide silanolate solution with a base content of 6 wt.% was obtained and stored for later use.

[0049] II. Preparation of Terminating Agent

[0050] (1) Preparation of Terminator 1

[0051] 312 g of D3F, 37.2 g of DVTMDS, and 21.6 g of 85 wt.% phosphoric acid were added to a reaction flask, and a reaction apparatus equipped with a reflux condenser and a water separator was installed. DVTMDS was added to the water separator until the liquid level touched the inner edge of the separator, and nitrogen gas was pre-purged to remove water. The system temperature was set to 160 °C and heating was started, and the reaction was carried out under stirring. Nitrogen gas was continuously purged during the reaction to carry the generated water to the water separator for condensation and collection, which was then released periodically. After 8 hours of reaction, a colorless, transparent fluorinated silicon-based phosphate ester with an acid content of 5 wt.% was obtained and stored for later use.

[0052] (2) Preparation of Terminator 2

[0053] 310 g of D3F, 18.6 g of DVTMDS, and 15.4 g of 85 wt.% phosphoric acid were added to a reaction flask, and a reaction apparatus equipped with a reflux condenser and a water separator was installed. DVTMDS was added to the water separator until the liquid level touched the inner edge of the separator, and nitrogen gas was pre-purged to remove water. The system temperature was set to 170 °C and heating was started, and the reaction was carried out under stirring. Nitrogen gas was continuously purged during the reaction to carry the generated water to the water separator for condensation and collection, which was then released periodically. After 7.5 hours of reaction, a colorless, transparent fluorinated silicon-based phosphate ester with an acid content of 4 wt.% was obtained and stored for later use.

[0054] (3) Preparation of Terminator 3

[0055] 320 g of D3F, 48 g of DVTMDS, and 26 g of 85 wt.% phosphoric acid were added to a reaction flask, and a reaction apparatus equipped with a reflux condenser and a water separator was installed. DVTMDS was added to the water separator until the liquid level touched the inner edge of the separator, and nitrogen gas was pre-purged to remove water. The system temperature was set to 165 °C and heating was started, and the reaction was carried out under stirring. Nitrogen gas was continuously purged during the reaction to carry the generated water to the water separator for condensation and collection, which was then released periodically. After 7 hours of reaction, a colorless, transparent fluorinated silicon-based phosphate ester with an acid content of 6 wt.% was obtained and stored for later use.

[0056] The acid and alkali contents mentioned above were determined by titration, a test method well known to those skilled in the art, and will not be described in detail here.

[0057] Example 1

[0058] The preparation method of the vinyl fluorinated polysiloxane in this embodiment includes the following steps:

[0059] S1. Add 1000g of D3F and 89.7g of D3Vi to the reactor, heat to 70℃, evacuate to -10kPa, and purge with nitrogen to dehydrate for 1 hour.

[0060] S2 is heated to 100℃, 1.162g of catalyst 1 and 0.7g of deionized water are added, and the mixture is stirred and reacted for 5 hours.

[0061] S3 is cooled to 80℃, and a dehydration condensation reaction is carried out under vacuum. The pressure inside the reactor is controlled at -20kPa and maintained for 2 hours.

[0062] S4 was restored to normal pressure and temperature was maintained. 4.8g of end-capping agent vinyldimethylethoxysilane was added and the reaction was stirred for 2 hours. Then, 1.743g of terminator 1 was added and the mixture was stirred for another 2 hours while maintaining a vacuum of -40kPa.

[0063] S5 is heated to 180℃, evacuated to -100kPa, and nitrogen is introduced to remove low molecular weight compounds, thus obtaining vinyl fluorinated polysiloxane.

[0064] The structural formula of the vinyl fluorinated polysiloxane prepared in this embodiment is as follows:

[0065] .

[0066] The vinyl fluorinated polysiloxane prepared in this embodiment 1 HNMR spectrum as follows Figure 1 As shown, it can be seen that 1 The HNMR spectrum was clean, with no extraneous peaks: the sharp singlet at δ = 0-0.35 ppm was assigned to the repeating unit Si-CH3; the triplet at 0.80-1.00 ppm and the multiplet at 1.80-2.30 ppm together constituted the AB2 spin system of Si-CH2CH2CF3; the multiplet at 5.80-6.40 ppm corresponded to the three olefin protons of Si-CH=CH2. Integration results showed a vinyl to fluoropropyl molar ratio of 14:86, consistent with the theoretical feed ratio, confirming that the target product, a vinyl-containing fluorinated polysiloxane, has a well-defined structure and good purity.

[0067] The infrared spectrum of the vinyl fluorinated polysiloxane prepared in this embodiment is as follows: Figure 2 As shown, 3064cm -1 1598cm -1 1413cm -1 The peak at 1211 cm⁻¹ is the characteristic absorption peak of Si-CH=CH₂. -1 The peak at 1069 cm⁻¹ is a characteristic absorption peak of -CF₃. -1 The absorption peak at 764 cm⁻¹ is the stretching vibration absorption peak of Si-O-Si. -1 The peak at this location is the stretching vibration absorption peak of Si-CH3. The position, shape, and relative intensity of each characteristic peak are consistent with the target structure, and there are no significant impurity peaks, proving that the vinyl fluorinated polysiloxane was successfully synthesized with high purity, which can meet the requirements of subsequent crosslinking and functionalization.

[0068] Example 2

[0069] The preparation method of the vinyl fluorinated polysiloxane in this embodiment includes the following steps:

[0070] S1. Add 1000g of D3F and 184.3g of D3Vi to the reactor, heat to 75℃, evacuate to -15kPa, and purge with nitrogen to dehydrate for 1 hour.

[0071] S2 is heated to 140℃, 1.334g of catalyst 2 and 0.5g of deionized water are added, and the mixture is stirred and reacted for 3 hours.

[0072] S3 is cooled to 75℃, and a dehydration condensation reaction is carried out under vacuum. The pressure inside the reactor is controlled at -20kPa and maintained for 2 hours.

[0073] S4 was restored to normal pressure, and the temperature was maintained. 4.7g of the end-capping agent vinyldimethylethoxysilane was added. After stirring for 2 hours, 2.668g of terminator 2 was added, and stirring was continued for 2 hours while maintaining a vacuum of -35kPa.

[0074] S5 is heated to 175℃, evacuated to -95kPa, and nitrogen gas is introduced to remove low molecular weight compounds, thus obtaining vinyl fluorinated polysiloxane.

[0075] The structural formula of the vinyl fluorinated polysiloxane prepared in this embodiment is as follows:

[0076] .

[0077] The vinyl fluorinated polysiloxane prepared in this embodiment 1 HNMR spectrum as follows Figure 3 As shown in the figure. The integration results show that the molar ratio of vinyl to fluoropropyl is 25:75, which is consistent with the theoretical feed ratio, confirming that the target product, vinyl-containing fluorinated polysiloxane, has a well-defined structure and good purity.

[0078] Example 3

[0079] The preparation method of the vinyl fluorinated polysiloxane in this embodiment includes the following steps:

[0080] S1. Add 1000g of D3F and 138g of D3Vi to the reactor, heat to 80℃, evacuate to -20kPa, and purge with nitrogen to dehydrate for 2 hours.

[0081] S2 is heated to 120℃, 1.556g of catalyst 3 and 1g of deionized water are added, and the mixture is stirred and reacted for 4 hours.

[0082] S3 is cooled to 70℃, and a dehydration condensation reaction is carried out under vacuum. The pressure inside the reactor is controlled at -20kPa and maintained for 2 hours.

[0083] S4 was restored to normal pressure and the temperature was maintained. 4.6g of the end-capping agent vinyldimethylethoxysilane was added. After stirring for 3h, 2.723g of terminator 3 was added. Stirring was continued for 3h and the vacuum degree was maintained at -30kPa.

[0084] S5 is heated to 170℃, evacuated to -90kPa, and nitrogen is introduced to remove low molecular weight compounds, thus obtaining vinyl fluorinated polysiloxane.

[0085] The structural formula of the vinyl fluorinated polysiloxane prepared in this embodiment is as follows:

[0086] .

[0087] The vinyl fluorinated polysiloxane prepared in this embodiment 1 HNMR spectrum as follows Figure 4 As shown in the figure. The integration results show that the molar ratio of vinyl to fluoropropyl is 22:78, which is consistent with the theoretical feed ratio, confirming that the target product, vinyl-containing fluorinated polysiloxane, has a well-defined structure and good purity.

[0088] Comparative Example 1

[0089] The difference from Example 1 is that deionized water was not added in step S2. It was found that during the polymerization stage within 10 minutes after the addition of catalyst 1, the reaction experienced explosive polymerization, the viscosity of the system increased rapidly, and eventually exceeded the maximum torque of the stirrer, forcing the experiment to be stopped.

[0090] Comparative Example 2

[0091] The difference from Example 2 is that in step S4, 3.3g of DVTMDS is used instead of 4.7g of the end-capping agent vinyldimethylethoxysilane.

[0092] Comparative Example 3

[0093] The difference from Example 2 is that catalyst 2 was replaced with commercially available potassium polysiloxane alkali gel (Aladdin 236868, diluted to 5 wt.% with end-vinyl silicone oil DYSIL-VF500), and terminator 2 was replaced with commercially available silicon-based phosphate ester (Shanghai Yuanye Biotechnology Co., Ltd. S24229, diluted to 5 wt.% with end-vinyl silicone oil DYSIL-VF500). It was found that a more obvious turbidity occurred after the addition of the terminator, and the turbidity of the product became even more pronounced after the removal of low molecular weight compounds in step S5.

[0094] Comparative Example 4

[0095] The difference from Example 1 is that in step S2, catalyst 1 was added after heating to 150°C. It was found that the initial reaction was significantly more vigorous, and the addition of deionized water as a retarder could not effectively control the degree of reaction; after subsequent cooling and condensation, the viscosity increased significantly, exceeding the preset viscosity.

[0096] The vinyl fluorinated polysiloxanes prepared in Examples 1-3 and Comparative Examples 1-4 were tested. Viscosity was tested according to GB / T 10247-2008 "Viscosity Test Method"; vinyl content was determined by titration. The test results are shown in Table 1.

[0097] Table 1. Test results of vinyl fluorinated polysiloxanes prepared in Examples 1-3 and Comparative Examples 1-4

[0098]

[0099] As shown in Table 1, by adjusting the amounts of D3F, D3Vi, and the capping agent vinyldimethylethoxysilane in Examples 1, 2, and 3, the viscosity and vinyl content of the product can be precisely controlled. The test results of Example 1 and Comparative Example 1 show that the viscosity of the product in Comparative Example 1 increased uncontrollably, exceeding the maximum torque of the stirrer, forcing it to stop. The main reason is that this invention uses deionized water as a retarder, and the hydroxide ions (OH-) in the water molecules... - It can interact with the active chain ends (such as Si-OK). + The chain transfer reaction occurs, interrupting the continuous growth of the chain, which makes the polymerization reaction tend to be stable, thereby inhibiting the rapid polymerization.

[0100] Comparative Example 2 used DVTMDS as the end-capping agent. Due to the high Si-Vi bond breaking energy barrier of DVTMDS and its mismatch with the ring-opening reactivity of D3F, the end-capping efficiency of DVTMDS was low, resulting in increased viscosity.

[0101] Comparing Example 2 and Comparative Example 3, it can be seen that the catalyst and terminator used in this invention have excellent compatibility with the product, while ordinary catalysts and terminators can lead to a decrease in the appearance of the product, making the product cloudy.

[0102] Comparing Example 1 and Comparative Example 4, it can be seen that the initial polymerization temperature of Comparative Example 4 was too high, resulting in a rapid reaction in the early stage of polymerization, which could not effectively control the increase in product viscosity.

Claims

1. A method for preparing vinyl-containing fluorinated polysiloxanes, characterized in that, Includes the following steps: S1 mixes trifluoropropylmethylcyclotrisiloxane and trivinyltrimethylcyclotrisiloxane, heats to 70-80°C, draws a vacuum, and introduces nitrogen gas to dehydrate; S2 is heated to 100-140℃, and the catalyst, fluorinated potassium hydroxide silanolate, and the retarder, deionized water, are added. The mixture is stirred and reacted for 3-5 hours. The catalyst, fluorinated potassium hydroxide silanolate, is prepared by mixing trifluoropropylmethylcyclotrisiloxane and divinyltetramethyldisiloxane and heating the mixture to 160-170℃. Potassium hydroxide is added under stirring, and nitrogen gas is continuously introduced during the reaction. After reacting for 7-8 hours, a fluorinated potassium hydroxide silanolate solution with an alkali content of 4-6 wt.% is obtained. S3 is cooled to 70-80℃ and subjected to a dehydration condensation reaction under vacuum for 2-3 hours. S4 was restored to normal pressure and temperature. The end-capping agent vinyldimethylethoxysilane was added, and the reaction was stirred for 2-3 hours. Then, the terminator fluorosilicic phosphate was added, and stirring continued for another 2-3 hours while maintaining a vacuum of -40 to -30 kPa. The fluorosilicic phosphate was prepared as follows: trifluoropropylmethylcyclotrisiloxane, divinyltetramethyldisiloxane, and phosphoric acid were mixed and heated to 160-170°C, reacting under stirring for 7-8 hours. Nitrogen gas was continuously introduced during the reaction, and the generated water was separated to obtain a fluorosilicic phosphate with an acid content of 4-6 wt.%. S5 is heated to 170-180℃, evacuated to -100~-90kPa, and nitrogen is introduced to remove low molecular weight compounds, thus obtaining vinyl fluorinated polysiloxane. The total mass ratio of trifluoropropylmethylcyclotrisiloxane, trivinyltrimethylcyclotrisiloxane and end-capping agent to catalyst and retarder is 100: (0.01-0.16): (0.005-0.3).

2. The method for preparing vinyl fluorinated polysiloxane as described in claim 1, characterized in that, The mass ratio of trifluoropropylmethylcyclotrisiloxane, trivinyltrimethylcyclotrisiloxane and the capping agent vinyldimethylethoxysilane added in step S1 is 100:(8.5-18.5):(0.4-0.5).

3. The method for preparing vinyl fluorinated polysiloxane as described in claim 1, characterized in that, In step S1, the vacuum is evacuated to -20~-10 kPa, and the water is dehydrated for 1-2 hours.

4. The method for preparing vinyl fluorinated polysiloxane as described in claim 1, characterized in that, In the preparation method of the catalyst fluorine-containing potassium hydroxide silanol salt in step S2, the mass ratio of trifluoropropylmethylcyclotrisiloxane, divinyltetramethyldisiloxane and potassium hydroxide is 100:(55-65):(6.5-10).

5. The method for preparing vinyl fluorinated polysiloxane as described in claim 1, characterized in that, In step S4, the mass ratio of the terminator to the catalyst is (1.5-2):

1.

6. The method for preparing vinyl fluorinated polysiloxane as described in claim 1, characterized in that, In the preparation method of the terminating agent fluorosilicic phosphate in step S4, the mass ratio of trifluoropropylmethylcyclotrisiloxane, divinyltetramethyldisiloxane and phosphoric acid is 100:(5-15):(4.2-7).

7. A vinyl fluorinated polysiloxane, characterized in that, It is prepared by the method for preparing vinyl fluorinated polysiloxanes as described in any one of claims 1-6.

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