A polyvinyl perfluoropolyether fluorosilicone oil and its preparation method

Abstract

This invention belongs to the field of perfluoropolyether fluorosilicone oil preparation technology, specifically relating to a polyvinyl perfluoropolyether fluorosilicone oil and its preparation method. The invention first prepares a polyvinyl polysiloxane by ring-opening reaction of tetramethyltetravinylcyclotetrasiloxane and a cyclosiloxane, then reacts it with perfluoropolyether trimethoxysilane to obtain a polyvinyl perfluoropolyether fluorosilicone oil. A modified catalyst prepared by reacting 1H-imidazo[4,5-g]isoquinoline with 2-iodopropane to prepare a modified organic base, followed by reaction with tris(pentafluorophenyl)boron and thiol, exhibits high reactivity, avoiding the difficulty of impurity removal using multiple catalysts. The perfluoropolyether trimethoxysilane prepared by reacting perfluoropolyether alcohol and allyl chloroformate with trimethoxysilane exhibits excellent mechanical properties. The preparation process of this invention is relatively simple, reducing the use of fluorinated solvents during the reaction, and the resulting product contains more vinyl functional groups, exhibiting high crosslinking degree and corrosion resistance.

Description

Technical Field

[0001] This invention belongs to the field of perfluoropolyether fluorosilicone oil preparation technology, specifically relating to a polyvinyl perfluoropolyether fluorosilicone oil and its preparation method. Background Technology

[0002] Fluorosilicone oils refer to a class of silicone oils in which the side groups of the polysiloxane chain contain fluorinated groups. Introducing fluorinated groups into organosilicon polymers can reduce surface energy and improve solvent resistance, weather resistance, and abrasion resistance. Perfluoropolyethers are high-molecular polymers prepared from perfluorinated monomers. Compared with conventional fluorocarbon materials, perfluoropolyethers, due to the introduction of oxygen, have a ether bond structure that offers better biodegradability and lower toxicity than a carbon-carbon structure.

[0003] Chinese invention patent CN106336514B discloses a polyvinyl perfluoropolyether fluorosilicone oil and its preparation method. This polyvinyl perfluoropolyether fluorosilicone oil is prepared using aminosilane coupling agents, tetramethyltetravinylcyclotetrasiloxane, hexamethyldisiloxane, and perfluoropolyether compounds as main raw materials. This polyvinyl perfluoropolyether fluorosilicone oil exhibits high vinyl functionality and can significantly improve the mechanical strength and acid corrosion resistance of rubber materials when used in their preparation. However, existing technologies have not further improved the formulation of the raw material components and the type of catalyst used in the perfluoropolyether fluorosilicone oil to enhance its mechanical properties and corrosion resistance when applied to rubber products. Summary of the Invention

[0004] The purpose of this invention is to provide a polyvinyl perfluoropolyether fluorosilicone oil and its preparation method, which solves the problem that the existing technology has not further improved the raw material composition and catalyst type of the perfluoropolyether fluorosilicone oil, so as to improve the mechanical properties and corrosion resistance when applied to rubber products.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a polyvinyl perfluoropolyether fluorosilicone oil includes the following steps:

[0007] S1. Add tetramethyltetravinylcyclotetrasiloxane and cyclosiloxane to the reactor. After adding n-hexane, purge the air with nitrogen three times. Add the modified catalyst dropwise while stirring, and complete the dropwise addition within 30-40 minutes. After the dropwise addition is completed, react at 70-90℃ for 2-6 hours.

[0008] S2. Add a capping agent to the reaction system of S1 for capping treatment, cool the reaction solution and let it stand to separate into layers, collect the oil layer, wash it with water until neutral, and then distill it under reduced pressure to obtain polyvinyl polysiloxane.

[0009] S3. Add polyvinyl polysiloxane and perfluoropolyether trimethoxysilane to the reactor, add the modified catalyst while stirring, and react at 70~90℃ for 5~8h.

[0010] After the reaction system of S4 and S3 was cooled to room temperature, methanol and trifluorotoluene were added for extraction. The mixture was allowed to stand and separate into layers. The lower layer liquid was collected and distilled under reduced pressure to obtain polyvinyl perfluoropolyether fluorosilicone oil.

[0011] Preferably, the cyclosiloxane in S1 is one or more combinations of octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, and trimethylcyclotrisiloxane.

[0012] Preferably, the mass ratio of tetramethyltetravinylcyclotetrasiloxane, n-hexane, cyclosiloxane and modified catalyst in S1 is 1~2:5~7:6~8:0.2~0.5.

[0013] Preferably, the capping agent in S2 is one or a combination of ethanol, methanol and deionized water.

[0014] Preferably, the amount of end-capping agent added in S2 is 80-90 wt% of the total amount of tetramethyltetravinylcyclotetrasiloxane and cyclosiloxane added in S1.

[0015] Preferably, the mass ratio of polyvinyl polysiloxane, modified catalyst and perfluoropolyether trimethoxysilane in S3 is 5~8:0.2~0.5:1~3.

[0016] Preferably, the method for preparing the modified catalyst includes the following steps:

[0017] S11. Add tris(pentafluorophenyl)boron to ethyl acetate, add modified organic base and thiol while stirring, and react at room temperature for 12-16 h.

[0018] S12. After filtering the reaction system to remove ethyl acetate, wash it 2-3 times with n-hexane and dry it to obtain the modified catalyst.

[0019] Preferably, the mass ratio of tris(pentafluorophenyl)boron, ethyl acetate, modified organic base and thiol in S11 is 2~3:60~80:10~15:5~7.

[0020] Preferably, the method for preparing the modified organic base includes the following steps:

[0021] S21. Add 1H-imidazo[4,5-g]isoquinoline and base catalyst to toluene, heat to 70~80℃ and react for 1~2h. After the reaction is completed, cool the system to room temperature.

[0022] S22. Add 2-iodopropane dropwise to the system over 1-2 hours. Heat the mixture to 95-100°C and reflux for 36-48 hours. After the reaction is complete, add deionized water and dichloromethane for extraction and vacuum drying to obtain iodized salt.

[0023] S23. Iodized salt is added to toluene, and a toluene solution of potassium hexamethyldisilamide is added. The mixture is reacted at room temperature for 12-18 hours. After the reaction is completed, the solid is collected by filtration, extracted with n-hexane, and recrystallized at -10 to 0℃ to obtain the modified organic base.

[0024] Preferably, the synthetic reaction principle involved in the preparation of the modified organic base is as follows:

[0025]

[0026] Preferably, the alkaline catalyst in S21 is one or more combinations of potassium carbonate, potassium hydroxide, and sodium hydroxide.

[0027] Preferably, the mass ratio of 1H-imidazo[4,5-g]isoquinoline, base catalyst, toluene and 2-iodopropane in S21 and S22 is 4~6:2~3:15~30:20~23.

[0028] Preferably, the mass ratio of iodine salt to potassium hexamethyldisilamide in S23 is 2:1 to 1.2.

[0029] Preferably, the preparation method of the perfluoropolyether trimethoxysilane includes the following steps:

[0030] S31. Add perfluoropolyether alcohol to cyclohexane, add sodium hydride while stirring, and add allyl chloroformate dropwise over 1-2 hours. Heat to 55-65℃ and react for 12-20 hours to obtain a mixture.

[0031] S32. After the reaction is complete, the mixture is cooled to room temperature, neutralized to neutral by adding 10wt% hydrochloric acid, washed with water 2-3 times, extracted with perfluorocyclic ether, and fractionated under low pressure to obtain intermediate product 1.

[0032] S33. Add intermediate product 1 and chloroplatinic acid to cyclohexane, heat to 55~65℃ and then add trimethoxysilane dropwise over 1~2 hours. Keep at 55~65℃ for 3~4 hours, then heat to 70~80℃ and react for 12~16 hours. Low-pressure fractionation yields perfluoropolyether trimethoxysilane.

[0033] Preferably, the synthesis reaction principle involved in the preparation of the perfluoropolyether trimethoxysilane is as follows:

[0034]

[0035] Preferably, the mass ratio of perfluoropolyether alcohol, cyclohexane, sodium hydride and allyl chloroformate in S31 is 1~5:5~10:0.1~0.3:0.1~0.3.

[0036] Preferably, the mass ratio of intermediate product 1, chloroplatinic acid, cyclohexane and trimethoxysilane in S33 is 2:0.1~0.3:1~5:0.5~0.6.

[0037] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0038] 1. Based on existing technology, this invention optimizes the preparation method of polyvinyl perfluoropolyether fluorosilicone oil. First, tetramethyltetravinylcyclotetrasiloxane and cyclosiloxane are reacted to open the ring to prepare polyvinyl polysiloxane, which is then reacted with perfluoropolyether trimethoxysilane to prepare polyvinyl perfluoropolyether fluorosilicone oil. This reaction process is relatively simple, easy to operate and control, and reduces the use of fluorinated solvents during the reaction. The resulting polyvinyl perfluoropolyether fluorosilicone oil contains more vinyl functional groups and has higher crosslinking degree and corrosion resistance.

[0039] 2. This invention prepares Lewis acid-base pair modified catalysts by reacting tris(pentafluorophenyl)boron with modified organic bases and thiols. The reaction operation is relatively simple and requires less energy. Tris(pentafluorophenyl)boron and modified organic bases have large steric hindrance, preventing them from approaching each other and thus eliminating interaction forces. Therefore, the modified catalyst prepared by tris(pentafluorophenyl)boron with modified organic bases and thiols can still maintain high reactivity in catalyzing ring-opening and addition reactions, avoiding the problem of difficulty in removing impurities when using multiple catalysts.

[0040] 3. The modified organic base prepared by the present invention through the reaction of 1H-imidazo[4,5-g]isoquinoline with 2-iodopropane has large steric hindrance and lone pairs of electrons. The catalyst formed by reacting with tris(pentafluorophenyl)boron has higher catalytic activity than tris(pentafluorophenyl)boron alone in catalyzing ring-opening and addition reactions.

[0041] 4. In this invention, intermediate product 1 is prepared by reacting perfluoropolyether alcohol and allyl chloroformate, and then added to trimethoxysilane to prepare perfluoropolyether trimethoxysilane. The utilization rate of raw materials is high, and waste and by-product generation are reduced. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1: A method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to this example includes the following steps:

[0044] S1. Add 20g of tetramethyltetravinylcyclotetrasiloxane and 120g of octamethylcyclotetrasiloxane to the reactor. After adding 100g of n-hexane, purge the air with nitrogen three times. Add 5g of modified catalyst dropwise while stirring. The addition is completed within 40min. After the addition is completed, react at 80℃ for 4h.

[0045] S2. Add 112g of 30wt% ethanol aqueous solution to the reaction system of S1 for end-capping treatment. Cool the reaction solution to room temperature, let it stand and separate into layers. Collect the oil layer, wash it with water until neutral, and then distill it under reduced pressure to obtain polyvinyl polysiloxane.

[0046] S3. Add 100g of polyvinyl polysiloxane and 30g of perfluoropolyether trimethoxysilane to the reactor, add 5g of modified catalyst while stirring, and react at 80℃ for 6h.

[0047] After the reaction system of S4 and S3 was cooled to room temperature, 150 ml of methanol and 150 ml of trifluorotoluene were added for extraction. The mixture was allowed to stand and separate into layers. The lower layer liquid was collected and distilled under reduced pressure to obtain polyvinyl perfluoropolyether fluorosilicone oil.

[0048] The preparation method of the modified catalyst in this embodiment includes the following steps:

[0049] S11. Add 3.3g of tris(pentafluorophenyl)boron to 70g of ethyl acetate, and add 12g of modified organic base and 6.2g of thiol while stirring. React at room temperature for 12h.

[0050] S12. After filtering the reaction system to remove ethyl acetate, wash it three times with n-hexane and dry it to obtain the modified catalyst.

[0051] The method for preparing the modified organic base in this embodiment includes the following steps:

[0052] S21. Add 5.1g of 1H-imidazo[4,5-g]isoquinoline and 2.7g of potassium carbonate to 30g of toluene, heat to 70℃ and react for 2h. After the reaction is complete, cool the system to room temperature.

[0053] S22. Add 25.5g of 2-iodopropane dropwise to the system over 2 hours. Heat the mixture to 100°C and reflux for 48 hours. After the reaction is complete, add 30ml of deionized water and 30ml of dichloromethane for extraction. Dry under vacuum to obtain iodized salt.

[0054] S23. Add 20g of iodized salt to 20ml of toluene, add 30ml of toluene solution containing 10g of potassium hexamethyldisilamine, and react at room temperature for 18h. After the reaction is complete, filter and collect the solid, extract with n-hexane, and recrystallize at -10℃ to obtain the modified organic base.

[0055] The preparation method of the perfluoropolyether trimethoxysilane in this embodiment includes the following steps:

[0056] S31. Add 3g of perfluoropolyether alcohol with a number average molecular weight of about 3000 to 10g of cyclohexane, add 0.2g of sodium hydride while stirring, and add 0.18g of allyl chloroformate dropwise over 2 hours. Heat to 60℃ and react for 18 hours to obtain a mixture.

[0057] S32. After the reaction is complete, the mixture is cooled to room temperature, neutralized to neutral by adding 10wt% hydrochloric acid, washed twice with water, extracted with 10ml of perfluorocyclic ether, and fractionated under low pressure to obtain intermediate product 1.

[0058] S33. Add 2g of intermediate product 1 and 0.1g of chloroplatinic acid to cyclohexane, heat to 60℃, and then add 0.5g of trimethoxysilane dropwise over 2 hours. After maintaining the temperature at 60℃ for 4 hours, heat to 75℃ and react for 12 hours. The perfluoropolyether trimethoxysilane is obtained by low-pressure fractionation.

[0059] Example 2, a method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to this example, includes the following steps:

[0060] S1. Add 40g of tetramethyltetravinylcyclotetrasiloxane and 120g of hexamethylcyclotrisiloxane to the reactor. After adding 140g of n-hexane, purge the air with nitrogen three times. Add 6g of modified catalyst dropwise while stirring. The addition is completed within 30min. After the addition is completed, react at 75℃ for 6h.

[0061] S2. Add 130g of 40wt% ethanol aqueous solution to the reaction system of S1 for end-capping treatment. Cool the reaction solution to room temperature, let it stand and separate into layers. Collect the oil layer, wash it with water until neutral, and then distill it under reduced pressure to obtain polyvinyl polysiloxane.

[0062] S3. Add 100g of polyvinyl polysiloxane and 40g of perfluoropolyether trimethoxysilane to the reactor, add 2.5g of modified catalyst while stirring, and react at 90℃ for 8h.

[0063] After the reaction systems S4 and S3 were cooled to room temperature, 200 ml of methanol and 200 ml of trifluorotoluene were added for extraction. The mixture was allowed to stand and separate into layers. The lower layer was collected and distilled under reduced pressure to obtain polyvinyl perfluoropolyether fluorosilicone oil.

[0064] The preparation method of the modified catalyst in this embodiment includes the following steps:

[0065] S11. Add 6.6g of tris(pentafluorophenyl)boron to 80g of ethyl acetate, and add 14.9g of modified organic base and 6.8g of thiol while stirring. React at room temperature for 18h.

[0066] S12. After filtering the reaction system to remove ethyl acetate, wash it twice with n-hexane and dry it to obtain the modified catalyst.

[0067] The method for preparing the modified organic base in this embodiment includes the following steps:

[0068] S21. Add 4.2g of 1H-imidazo[4,5-g]isoquinoline and 2.7g of potassium hydroxide to 35g of toluene, heat to 75℃ and react for 2h. After the reaction is complete, cool the system to room temperature.

[0069] S22. Add 27.7 g of 2-iodopropane dropwise to the system over 2 hours. Heat the mixture to 95 °C and reflux for 48 hours. After the reaction is complete, add 30 ml of deionized water and 30 ml of dichloromethane for extraction. Dry under vacuum to obtain iodized salt.

[0070] S23. Add 20g of iodized salt to 20ml of toluene, add 30ml of toluene solution containing 10g of potassium hexamethyldisilamine, and react at room temperature for 12h. After the reaction is complete, filter and collect the solid, extract with n-hexane, and recrystallize at -5℃ to obtain the modified organic base.

[0071] The preparation method of the perfluoropolyether trimethoxysilane in this embodiment includes the following steps:

[0072] S31. Add 4g of perfluoropolyether alcohol with a number average molecular weight of about 4000 to 10g of cyclohexane, add 0.3g of sodium hydride while stirring, and add 0.24g of allyl chloroformate dropwise over 2 hours. Heat to 65℃ and react for 20 hours to obtain a mixture.

[0073] S32. After the reaction is complete, the mixture is cooled to room temperature, neutralized to neutral by adding 10wt% hydrochloric acid, washed 3 times with water, extracted with 15ml of perfluorocyclic ether, and fractionated under low pressure to obtain intermediate product 1.

[0074] S33. Add 2g of intermediate product 1 and 0.2g of chloroplatinic acid to cyclohexane, heat to 55℃, and then add 0.55g of trimethoxysilane dropwise over 2 hours. After maintaining the temperature at 55℃ for 3 hours, heat to 80℃ and react for 16 hours. The perfluoropolyether trimethoxysilane is obtained by low-pressure fractionation.

[0075] Example 3: A method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to this example includes the following steps:

[0076] S1. Add 30g of tetramethyltetravinylcyclotetrasiloxane and 180g of trimethylcyclotrisiloxane to the reactor. After adding 150g of n-hexane, purge the air with nitrogen three times. Add 10g of modified catalyst dropwise while stirring, and complete the addition within 30min. After the addition is complete, react at 70℃ for 8h.

[0077] S2. Add 185g of 50wt% methanol aqueous solution to the reaction system of S1 for end-capping treatment. Cool the reaction solution to room temperature, let it stand and separate into layers. Collect the oil layer, wash it with water until neutral, and then distill it under reduced pressure to obtain polyvinyl polysiloxane.

[0078] S3. Add 120g of polyvinyl polysiloxane and 15g of perfluoropolyether trimethoxysilane to the reactor, add 3g of modified catalyst while stirring, and react at 80℃ for 8h.

[0079] After the reaction system of S4 and S3 was cooled to room temperature, 150 ml of methanol and 150 ml of trifluorotoluene were added for extraction. The mixture was allowed to stand and separate into layers. The lower layer liquid was collected and distilled under reduced pressure to obtain polyvinyl perfluoropolyether fluorosilicone oil.

[0080] The preparation method of the modified catalyst in this embodiment includes the following steps:

[0081] S11. Add 2.6g of tris(pentafluorophenyl)boron to 60g of ethyl acetate, and add 15g of modified organic base and 5.2g of thiol while stirring. React at room temperature for 14h.

[0082] S12. After filtering the reaction system to remove ethyl acetate, wash it three times with n-hexane and dry it to obtain the modified catalyst.

[0083] The method for preparing the modified organic base in this embodiment includes the following steps:

[0084] S21. Add 5.1g of 1H-imidazo[4,5-g]isoquinoline and 2g of potassium carbonate to 25g of toluene, heat to 70℃ and react for 1h. After the reaction is complete, cool the system to room temperature.

[0085] S22. Add 15.3g of 2-iodopropane dropwise to the system over 2 hours. Heat the mixture to 95°C and reflux for 42 hours. After the reaction is complete, add 30ml of deionized water and 30ml of dichloromethane for extraction. Dry under vacuum to obtain iodized salt.

[0086] S23. Add 20g of iodized salt to 20ml of toluene, add 30ml of toluene solution containing 12g of potassium hexamethyldisilamine, and react at room temperature for 18h. After the reaction is complete, filter and collect the solid, extract with n-hexane, and recrystallize at 0℃ to obtain the modified organic base.

[0087] The preparation method of the perfluoropolyether trimethoxysilane in this embodiment includes the following steps:

[0088] S31. Add 3.5g of perfluoropolyether alcohol with a number-average molecular weight of approximately 3500 to 10g of cyclohexane, add 0.2g of sodium hydride while stirring, and add 0.12g of allyl chloroformate dropwise over 2 hours. Heat the mixture to 60°C and react for 20 hours to obtain a mixed solution.

[0089] S32. After the reaction is complete, the mixture is cooled to room temperature, neutralized to neutral by adding 10wt% hydrochloric acid, washed twice with water, extracted with 10ml of perfluorocyclic ether, and fractionated under low pressure to obtain intermediate product 1.

[0090] S33. Add 2g of intermediate product 1 and 0.1g of chloroplatinic acid to cyclohexane, heat to 60℃, and then add 0.5g of trimethoxysilane dropwise over 2 hours. After maintaining the temperature at 60℃ for 4 hours, heat to 80℃ and react for 16 hours. The perfluoropolyether trimethoxysilane is obtained by low-pressure fractionation.

[0091] Example 4, a method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to this example, includes the following steps:

[0092] S1. Add 20g of tetramethyltetravinylcyclotetrasiloxane, 120g of octamethylcyclotetrasiloxane and 20g of hexamethylcyclotrisiloxane to the reaction vessel. After adding 120g of n-hexane, purge the air with nitrogen three times. Add 10g of modified catalyst dropwise under stirring, and complete the dropwise addition within 30min. After the dropwise addition is completed, react at 90℃ for 2h.

[0093] S2. Add 136g of 40wt% ethanol aqueous solution to the reaction system of S1 for end-capping treatment. Cool the reaction solution to room temperature, let it stand and separate into layers. Collect the oil layer, wash it with water until neutral, and then distill it under reduced pressure to obtain polyvinyl polysiloxane.

[0094] S3. Add 100g of polyvinyl polysiloxane and 50g of perfluoropolyether trimethoxysilane to the reactor, add 8g of modified catalyst while stirring, and react at 80℃ for 8h.

[0095] After the reaction systems S4 and S3 were cooled to room temperature, 200 ml of methanol and 200 ml of trifluorotoluene were added for extraction. The mixture was allowed to stand and separate into layers. The lower layer was collected and distilled under reduced pressure to obtain polyvinyl perfluoropolyether fluorosilicone oil.

[0096] The preparation method of the modified catalyst in this embodiment includes the following steps:

[0097] S11. Add 3g of tris(pentafluorophenyl)boron to 75g of ethyl acetate, add 10g of modified organic base and 5g of thiol while stirring, and react at room temperature for 12h.

[0098] S12. After filtering the reaction system to remove ethyl acetate, wash it three times with n-hexane and dry it to obtain the modified catalyst.

[0099] The method for preparing the modified organic base in this embodiment includes the following steps:

[0100] S21. Add 5.9g of 1H-imidazo[4,5-g]isoquinoline and 3g of potassium carbonate to 40g of toluene, heat to 80℃ and react for 2h. After the reaction is completed, cool the system to room temperature.

[0101] S22. Add 23.6 g of 2-iodopropane dropwise to the system over 2 hours. Heat the mixture to 100°C and reflux for 36 hours. After the reaction is complete, add 30 ml of deionized water and 30 ml of dichloromethane for extraction. Dry under vacuum to obtain iodized salt.

[0102] S23. Add 20g of iodized salt to 20ml of toluene, add 30ml of toluene solution containing 11g of potassium hexamethyldisilamine, and react at room temperature for 12h. After the reaction is complete, filter and collect the solid, extract with n-hexane, and recrystallize at -10℃ to obtain the modified organic base.

[0103] The preparation method of the perfluoropolyether trimethoxysilane in this embodiment includes the following steps:

[0104] S31. Add 2.5g of perfluoropolyether alcohol with a number average molecular weight of about 2500 to 5g of cyclohexane, add 0.3g of sodium hydride while stirring, and add 0.12g of allyl chloroformate dropwise over 2 hours. Heat to 60℃ and react for 18 hours to obtain a mixture.

[0105] S32. After the reaction is complete, the mixture is cooled to room temperature, neutralized to neutral by adding 10wt% hydrochloric acid, washed twice with water, extracted with 10ml of perfluorocyclic ether, and fractionated under low pressure to obtain intermediate product 1.

[0106] S33. Add 2g of intermediate product 1 and 0.3g of chloroplatinic acid to cyclohexane, heat to 60℃, and then add 0.5g of trimethoxysilane dropwise over 1 hour. After maintaining the temperature at 60℃ for 4 hours, heat to 75℃ and react for 14 hours. The perfluoropolyether trimethoxysilane is obtained by low-pressure fractionation.

[0107] Example 5: A method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to this example includes the following steps:

[0108] S1. Add 20g of tetramethyltetravinylcyclotetrasiloxane and 160g of octamethylcyclotetrasiloxane to the reactor. After adding 140g of n-hexane, purge the air with nitrogen three times. Add 9g of modified catalyst dropwise while stirring. The addition is completed within 35min. After the addition is completed, react at 90℃ for 2h.

[0109] S2. Add 145g of 50wt% ethanol aqueous solution to the reaction system of S1 for end-capping treatment. Cool the reaction solution to room temperature, let it stand and separate into layers. Collect the oil layer, wash it with water until neutral, and then distill it under reduced pressure to obtain polyvinyl polysiloxane.

[0110] S3. Add 100g of polyvinyl polysiloxane and 60g of perfluoropolyether trimethoxysilane to the reactor, add 4g of modified catalyst while stirring, and react at 90℃ for 5h.

[0111] After the reaction system of S4 and S3 was cooled to room temperature, 150 ml of methanol and 150 ml of trifluorotoluene were added for extraction. The mixture was allowed to stand and separate into layers. The lower layer liquid was collected and distilled under reduced pressure to obtain polyvinyl perfluoropolyether fluorosilicone oil.

[0112] The preparation method of the modified catalyst in this embodiment includes the following steps:

[0113] S11. Add 3.3g of tris(pentafluorophenyl)boron to 70g of ethyl acetate, and add 12g of modified organic base and 6.2g of thiol while stirring. React at room temperature for 12h.

[0114] S12. After filtering the reaction system to remove ethyl acetate, wash it three times with n-hexane and dry it to obtain the modified catalyst.

[0115] The method for preparing the modified organic base in this embodiment includes the following steps:

[0116] S21. Add 5.9g of 1H-imidazo[4,5-g]isoquinoline and 2g of sodium carbonate to 30g of toluene, heat to 80℃ and react for 1h. After the reaction is complete, cool the system to room temperature.

[0117] S22. Add 17.7 g of 2-iodopropane dropwise to the system over 1 hour. Heat the mixture to 100 °C and reflux for 36 hours. After the reaction is complete, add 30 ml of deionized water and 30 ml of dichloromethane for extraction. Dry under vacuum to obtain iodized salt.

[0118] S23. Add 20g of iodized salt to 20ml of toluene, add 30ml of toluene solution containing 12g of potassium hexamethyldisilamine, and react at room temperature for 18h. After the reaction is complete, filter and collect the solid, extract with n-hexane, and recrystallize at -10℃ to obtain the modified organic base.

[0119] The preparation method of the perfluoropolyether trimethoxysilane in this embodiment includes the following steps:

[0120] S31. Add 1.5g of perfluoropolyether alcohol with a number average molecular weight of about 3000 to 5g of cyclohexane, add 0.1g of sodium hydride while stirring, and add 0.12g of allyl chloroformate dropwise over 2 hours. Heat to 65℃ and react for 12 hours to obtain a mixture.

[0121] S32. After the reaction is complete, the mixture is cooled to room temperature, neutralized to neutral by adding 10wt% hydrochloric acid, washed twice with water, extracted with 10ml of perfluorocyclic ether, and fractionated under low pressure to obtain intermediate product 1.

[0122] S33. Add 2g of intermediate product 1 and 0.1g of chloroplatinic acid to cyclohexane, heat to 55℃, and then add 0.6g of trimethoxysilane dropwise over 2 hours. After maintaining the temperature at 55℃ for 4 hours, heat to 75℃ and react for 16 hours. The perfluoropolyether trimethoxysilane is obtained by low-pressure fractionation.

[0123] Comparative Example 1 differs from Example 1 in that the modified catalyst is replaced with tris(pentafluorophenyl)boron.

[0124] Comparative Example 2 differs from Example 1 in that the 1H-imidazo[4,5-g]isoquinoline in the preparation method of the modified organic base is replaced with pyrido[2,3-b]pyrazine.

[0125] Comparative Example 3 differs from Example 1 in that perfluoropolyether alcohol is directly reacted with trimethoxysilane to prepare perfluoropolyether trimethoxysilane.

[0126] Performance testing

[0127] Preparation of modified rubber:

[0128] 1. Add methyl vinyl silicone rubber and carbon black to a two-roll mill and mix for 20 minutes. Add dicumyl peroxide vulcanizing agent and vulcanize at 150°C for 30 minutes. Each part of rubber contains 100g of methyl vinyl silicone rubber, 40g of carbon black and 15g of dicumyl peroxide vulcanizing agent.

[0129] 2. Take 2g of the polyvinyl perfluoropolyether fluorosilicone oil prepared in each example and comparative example and add it to methyl vinyl silicone rubber. Pass it through a two-roll mill 10 times, cool it to room temperature and let it stand for 48 hours. Then, vulcanize it again at 100°C for 2 hours and cool it to room temperature to obtain modified methyl vinyl silicone rubber.

[0130] Mechanical properties

[0131] The tensile strength, elongation at break, and hardness of modified methyl vinyl silicone rubber were determined according to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The test results are shown in Table 1 below:

[0132] Table 1

[0133]

[0134] As shown in Table 1, the modified methyl vinyl silicone rubbers of Examples 1-5 have tensile strengths between 9.6 and 10.4 MPa and elongation at break between 317 and 324%, indicating that the polyvinyl perfluoropolyether fluorosilicone oils prepared in each example have excellent mechanical properties. The modified methyl vinyl silicone rubbers of Examples 1-5 have hardnesses between 56 and 59 Shores, indicating that the polyvinyl perfluoropolyether fluorosilicone oils prepared in each example have the ability to enhance the hardness of methyl vinyl silicone rubber. In Comparative Example 3, the perfluoropolyether alcohol was directly reacted with trimethoxysilane to prepare perfluoropolyether trimethoxysilane, resulting in a shorter chain length and weaker hardness and crosslinking degree compared to the examples. The mechanical properties and hardness of the modified methyl vinyl silicone rubber obtained in Comparative Example 3 were both lower than those of the modified methyl vinyl silicone rubbers in the examples.

[0135] Corrosion resistance

[0136] The modified methyl vinyl silicone rubbers prepared in each example and comparative example were immersed in 3.5 wt% dilute hydrochloric acid for 72 h. The tensile strength, elongation at break, and hardness of the modified methyl vinyl silicone rubbers after 72 h were measured. The test results are shown in Table 2 below:

[0137] Table 2

[0138]

[0139] As shown in Table 1, the modified methyl vinyl silicone rubbers prepared in Examples 1-5 showed a decrease in tensile strength of 0.4-0.5 MPa and a decrease in elongation at break of 2-3% after soaking in 3.5 wt% dilute hydrochloric acid for 72 hours. This indicates that the polyvinyl perfluoropolyether fluorosilicone oil of the present invention has excellent anti-corrosion properties.

[0140] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0141] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a polyvinyl perfluoropolyether fluorosilicone oil, characterized in that, Includes the following steps: S1. Add tetramethyltetravinylcyclotetrasiloxane and cyclosiloxane to the reactor. After adding n-hexane, purge the air with nitrogen three times. Add the modified catalyst dropwise while stirring, and complete the dropwise addition within 30-40 minutes. After the dropwise addition is completed, react at 70-90℃ for 2-6 hours. S2. Add one or more combinations of ethanol, methanol and deionized water to the reaction system of S1. The amount added is 80-90% of the total mass of tetramethyltetravinylcyclotetrasiloxane and cyclosiloxane added in S1. Cool the reaction solution and let it stand to separate into layers. Collect the oil layer, wash it with water until neutral, and then distill it under reduced pressure to obtain polyvinyl polysiloxane. S3. Add polyvinyl polysiloxane and perfluoropolyether trimethoxysilane to the reactor, add the modified catalyst while stirring, and react at 70~90℃ for 5~8h. After the reaction systems of S4 and S3 were cooled to room temperature, a mixed solvent of methanol and trifluorotoluene was added for extraction. The mixture was allowed to stand and separate into layers. The lower layer liquid was collected and distilled under reduced pressure to obtain polyvinyl perfluoropolyether fluorosilicone oil. The method for preparing the modified catalyst includes the following steps: S11. Add tris(pentafluorophenyl)boron to ethyl acetate, add modified organic base and thiol while stirring, and react at room temperature for 12-16 h. S12. After filtering out ethyl acetate from the reaction system of S11, wash with n-hexane 2-3 times and dry to obtain the modified catalyst. The preparation method of the perfluoropolyether trimethoxysilane includes the following steps: S31. Add perfluoropolyether alcohol to cyclohexane, add sodium hydride while stirring, and add allyl chloroformate dropwise over 1-2 hours. Heat to 55-65℃ and react for 12-20 hours to obtain a mixture. S32. After the reaction is complete, the mixture is cooled to room temperature, neutralized to neutral by adding 10wt% hydrochloric acid, washed with water 2-3 times, extracted with perfluorocyclic ether, and fractionated under low pressure to obtain intermediate product 1. S33. Add intermediate product 1 and chloroplatinic acid to cyclohexane, heat to 55~65℃ and then add trimethoxysilane dropwise over 1~2 hours. Keep at 55~65℃ for 3~4 hours and then heat to 70~80℃ for 12~16 hours. Low-pressure fractionation yields perfluoropolyether trimethoxysilane. The cyclosiloxane in S1 is one or more combinations of octamethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, and trimethylcyclotrisiloxane.

2. The method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to claim 1, characterized in that, The mass ratio of tetramethyltetravinylcyclotetrasiloxane, n-hexane, cyclosiloxane and modified catalyst in S1 is 1~2:5~7:6~8:0.2~0.

5.

3. The method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to claim 1, characterized in that... The mass ratio of polyvinyl polysiloxane, modified catalyst and perfluoropolyether trimethoxysilane in S3 is 5~8:0.2~0.5:1~3.

4. The method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to claim 1, characterized in that, The mass ratio of tris(pentafluorophenyl)boron, ethyl acetate, modified organic base and thiol in S11 is 2~3:60~80:10~15:5~7.

5. The method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to claim 1, characterized in that, The method for preparing the modified organic base includes the following steps: S21. Add 1H-imidazo[4,5-g]isoquinoline and base catalyst to toluene, heat to 70~80℃ and react for 1~2h. After the reaction is completed, cool the system to room temperature. S22. Add 2-iodopropane dropwise to the system of S21 over 1-2 hours. Heat the mixture to 95-100°C and reflux for 36-48 hours. After the reaction is complete, add deionized water and dichloromethane for extraction and vacuum drying to obtain iodized salt. S23. Iodized salt is added to toluene, followed by a toluene solution of potassium hexamethyldisilamide. The mixture is reacted at room temperature for 12-18 hours. After the reaction is complete, the solid is collected by filtration, extracted with n-hexane, and recrystallized at -10 to 0°C to obtain the modified organic base.

6. The method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to claim 5, characterized in that, The alkaline catalyst in S21 is one or more combinations of potassium carbonate, potassium hydroxide, and sodium hydroxide; the mass ratio of 1H-imidazo[4,5-g]isoquinoline, alkaline catalyst, toluene, and 2-iodopropane is 4~6:2~3:15~30:20~23; the mass ratio of iodide salt and potassium hexamethyldisilamide in S23 is 2:1~1.

2.

7. The method for preparing a polyvinyl perfluoropolyether fluorosilicone oil according to claim 1, characterized in that, In S31, the mass ratio of perfluoropolyether alcohol, cyclohexane, sodium hydride, and allyl chloroformate is 1~5:5~10:0.1~0.3:0.1~0.3; in S33, the mass ratio of intermediate product 1, chloroplatinic acid, cyclohexane, and trimethoxysilane is 2:0.1~0.3:1~5:0.5~0.

6.

8. A polyvinyl perfluoropolyether fluorosilicone oil prepared by the method of preparing a polyvinyl perfluoropolyether fluorosilicone oil according to any one of claims 1-7.

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