Preparation method of vinyl hydroxyl fluorosilicone oil

Abstract

The invention discloses a preparation method of vinyl hydroxyl fluorosilicone oil, and relates to the field of fluorosilicone rubber, which comprises the following steps: by taking trifluoropropyl methyl cyclotrisiloxane and a vinyl ring body as raw materials, adding an end-capping reagent accounting for 0.001-10g of the mass of the raw materials, a cationic catalyst accounting for 0.001-2g of the mass of the raw materials and a reaction aid accounting for 0.002-15g of the mass of the raw materials, washing with water to remove salts, and drying to obtain the vinyl hydroxyl fluorosilicone oil. And finally, reducing pressure to 120 DEG C, and stopping to obtain the vinyl hydroxyl fluorosilicone oil. The preparation method of the vinyl hydroxyl fluorosilicone oil comprises the following steps: by taking trifluoropropyl methyl cyclotrisiloxane (D3F) and a vinyl ring body as raw materials, adding an end-capping reagent, a cationic catalyst and a reaction aid, carrying out ring-opening copolymerization reaction, and controlling the reaction time, temperature and feeding ratio in the reaction process, thereby preparing the vinyl hydroxyl fluorosilicone oil. The process product is high in stability, the cost is reduced by reasonably selecting raw materials and controlling reaction conditions, and the synthesis process and the product performance are stable.

Description

Technical Field

[0001] The present invention relates to the technical field related to fluorosilicone rubber, and in particular to a method for preparing vinyl hydroxy fluorosilicone oil. Background Art

[0002] Vinyl hydroxy fluorosilicone oil is a polymer compound with both organic silicon groups (silicon oxygen bond skeleton) and fluorinated groups (fluorine-containing functional groups). Its preparation involves core technologies such as copolymerization, functional group introduction, and polymerization process optimization. In the field of fluorosilicone rubber, structuring causes the mixed fluorosilicone rubber to have poor processability, difficulty in re-mixing, short storage period, and poor rheology, which easily leads to product defects. The so-called structuring is that the rubber compound is obtained by mixing the reinforcing agent and rubber. During storage, the rubber compound hardens, the Mooney value increases, and gradually loses its processing performance. This is "structuring". The reason for the structuring is that the hydroxyl groups on the surface of silica and the hydroxyl groups on the silicone rubber molecules form micro-crosslinks or pseudo-crosslinks. In order to improve this situation, two methods are usually adopted: treating the surface of the reinforcing filler silica or adding a structuring control agent during mixing. However, the cost of treating silica is too high. Now most people use the method of adding a structuring control agent during mixing to treat silica in situ. Therefore, in fluoro Adding a structure control agent to the silicone rubber compound can enable the rubber to maintain good processing performance after storage. The use of a structure control agent not only solves the processability and storage stability of the fluorosilicone rubber compound, but also significantly improves the mechanical properties of the compound. In order to solve the above problems, reference can be made to the prior art (Chinese patent application number CN202310183166.0, application date 2023-02-25) disclosed a terminal hydroxyl vinyl fluorosilicone oil and its preparation method. The molecular structure of the terminal hydroxyl vinyl fluorosilicone oil in this preparation method contains two reactive groups, vinyl and hydroxyl. In the process of using it as a fluorosilicone rubber modification additive, the terminal hydroxyl group can significantly treat the silanol group on the surface of hydrophilic silica, improve the affinity between silica and fluorosilicone raw rubber molecules, and make it uniformly dispersed in the rubber system; the vinyl group can participate in the subsequent vulcanization reaction, enhance the winding and bridging effect of the raw rubber molecules, and improve the mechanical properties of the rubber. This product plays the combined role of a structuring control agent and a system crosslinker, and the preparation method of vinyl hydroxy silicone oil disclosed in the existing patent (application number CN202310503722.8, application date 2023-04-28 Chinese patent) can be referred to. In the synthesis process of vinyl hydroxy silicone oil, the control of temperature and pH value is very important, which affects the molecular weight of the vinyl hydroxy silicone oil. Therefore, a pH meter with a temperature measuring function is provided in the reactor, which can monitor the temperature and pH value of the mixture of crude vinyl hydroxy silicone oil and ammonium chloride aqueous solution in real time. A vinyl fluorinated polysiloxane and its preparation method disclosed in the prior art (application number CN202310091874.1, application date 2023-02-10 Chinese patent) are used for the first time to use hydroxy-terminated trifluoropropyl methyl polysiloxane and short-chain vinyl silicone oil as the main raw materials to prepare vinyl fluorosilicone oil or vinyl fluorosilicone rubber with controllable molecular weight and vinyl content. The raw materials used are all polymers, avoiding the production safety problems that may be caused by small molecule reactions.Compared to existing technologies, this method offers superior process and cost advantages. Both the hydroxyl-terminated trifluoropropyl methyl polysiloxane and the end-capping agent are linear polymers, maintaining corresponding reactivity during polymerization. Using a short-chain vinyl silicone oil end-capping agent, products containing both vinyl groups in the side chains and end groups can be prepared, extending its applicability. Compared to D3F, the production of hydroxyl-terminated trifluoropropyl methyl polysiloxane is more energy-efficient and environmentally friendly, and its storage and transportation are also safer. This method is in line with current development trends and holds great promise. It offers advantages such as rapid reaction speed, simple process, good safety, and high yield.

[0003] The commonly used structural agent for fluorosilicone rubber is hydroxyl fluorosilicone oil. The use of hydroxyl fluorosilicone oil as a structural control agent for fluorosilicone rubber has obvious effects and good compatibility. The resulting rubber compound has good transparency and excellent mechanical properties, but it cannot increase the crosslinking density, reduce the permanent deformation at break and low resilience.

[0004] SUMMARY OF THE INVENTION In view of the shortcomings in the art, the present invention provides a method for preparing vinyl hydroxy fluorosilicone oil, which has easy control of vinyl content, high fluorine content, low polymerization temperature, low energy consumption, high yield of target product and high stability.

[0005] Therefore, we propose a method for preparing vinyl hydroxy fluorosilicone oil in order to solve the above problems. Summary of the Invention

[0006] The object of the present invention is to provide a method for preparing vinyl hydroxyl fluorosilicone oil, so as to solve the problems raised in the above-mentioned background technology that the commonly used structural agent for fluorosilicone rubber on the market is hydroxyl fluorosilicone oil. The use of hydroxyl fluorosilicone oil as a fluorosilicone rubber structure control agent has obvious effects and good compatibility, and the resulting rubber compound has good transparency and excellent mechanical properties, but cannot increase the crosslinking density, reduce the permanent deformation at break and have low resilience.

[0007] To achieve the above-mentioned object, the present invention provides the following technical solution: a method for preparing vinyl hydroxy fluorosilicone oil, comprising: using trifluoropropyl methylcyclotrisiloxane and a vinyl ring body as raw materials, adding a capping agent with a mass of 0.001 to 10 g, a cationic catalyst with a mass of 0.001 to 2 g, and a reaction aid with a mass of 0.002 to 15 g, and conducting a polymerization reaction at 30 to 60° C. for 0.5 to 8 hours until the viscosity of the reaction system stabilizes; the vinyl ring body is a methyl vinyl siloxane ring body with a mass of 0.001 to 10 in the raw materials, and conducting a polymerization reaction until the viscosity of the reaction system stabilizes; adding an alkaline compound to neutralize the reaction system to neutrality, then washing with water to remove salts, and finally decompressing and degassing to 120° C. before stopping to obtain vinyl hydroxy fluorosilicone oil.

[0008] Preferably, the end-capping agent is tetramethyldihydroxydisiloxane or hydroxyfluorosilicone oil.

[0009] Preferably, the cationic catalyst is HCl solution or cationic resin.

[0010] Preferably, the auxiliary reaction agent is acetone or ethyl acetate.

[0011] Preferably, the methylvinylsiloxane ring body is trimethyltrivinylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, or pentamethylpentavinylcyclopentasiloxane.

[0012] Preferably, the vinyl hydroxy fluorosilicone oil is prepared by the above preparation method, and the viscosity of the vinyl hydroxy fluorosilicone oil is 31 to 809 mPa·s.

[0013] Preferably, the vinyl hydroxy fluorosilicone oil is used as a structure control agent and processing aid for fluorosilicone rubber.

[0014] Preferably, the mechanical properties of the fluorosilicone rubber include increasing the strength of the fluorosilicone rubber, improving the resilience, and reducing the permanent deformation at break.

[0015] Preferably, the mechanical properties of the fluorosilicone rubber include increasing the strength of the fluorosilicone rubber, improving the resilience, or reducing the permanent deformation at break.

[0016] Preferably, the vinyl hydroxy fluorosilicone oil is used alone as the structure control agent of fluorosilicone rubber, or together with the hydroxy fluorosilicone oil, as the structure control agent of fluorosilicone rubber.

[0017] Preparation method steps

[0018] Polymerization reaction

[0019] Raw materials: trifluoropropylmethylcyclotrisiloxane (D3F) and vinyl ring bodies (such as trimethyltrivinylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane and other methylvinylsiloxane ring bodies) as basic raw materials;

[0020] Additives:

[0021] End-capping agent: 0.001-10g of raw material mass, water, hydroxy fluorosilicone oil, tetramethyl dihydroxy disiloxane can be selected, used to control molecular weight and functional group end-capping;

[0022] Cationic catalyst: 0.001-2g of raw material mass, HCl, acetic acid, cationic resin, phosphoric acid can be selected, catalyzing the ring-opening polymerization reaction;

[0023] A reaction aid: 0.002-15g, selected from acetone, butanone, acetic anhydride, ethyl acetate, to improve system compatibility and reaction efficiency;

[0024] Conditions: reaction temperature 30-60°C, time 0.5-8h, until the viscosity of the system stabilizes (indicating the completion of the polymerization reaction).

[0025] Post-processing

[0026] Add alkaline compounds (such as NaHCO3 solution) to neutralize to eliminate catalyst residues;

[0027] Wash with water to remove salt impurities generated by the reaction;

[0028] The low-boiling substances were removed under reduced pressure (vacuum degree -0.096 MPa to -0.098 MPa), and the temperature was raised to 120°C and then stopped to obtain the target product.

[0029] (2) Product characteristics and applications

[0030] Chemical structure: The molecular chain contains both vinyl (-CH=CH2) and hydroxyl (-OH), with a fluorine content ≥30%. The vinyl content can be precisely controlled by the raw material ratio.

[0031] Performance parameters: viscosity range 31-809 mPa·s, yield ≥56%, excellent product stability (storage period ≥12 months).

[0032] Application scenarios:

[0033] Fluorosilicone rubber structure controller: used alone or in combination with hydroxyl fluorosilicone oil, it can inhibit structuring and improve processing fluidity;

[0034] Cross-linking density regulator: Through the participation of vinyl groups in the cross-linking reaction, the cross-linking density is increased, the permanent deformation at break is reduced, and the resilience is improved;

[0035] Special additives for silicone rubber: improve oil resistance and expand industrial application scenarios.

[0036] Compared with the prior art, the present invention has the following beneficial effects: the preparation method of the vinyl hydroxy fluorosilicone oil;

[0037] 1. Using trifluoropropylmethylcyclotrisiloxane (D3F) and a vinyl ring as raw materials, adding a capping agent, a cationic catalyst and a reaction aid, a ring-opening copolymerization reaction is carried out. During the reaction process, the reaction time, temperature and the ratio of the added materials are controlled to prepare vinyl hydroxy fluorosilicone oil. The product of this process is highly stable. By rationally selecting raw materials and controlling reaction conditions, the cost is reduced, and the synthesis process and product performance are stable.

[0038] 2. Vinyl hydroxy fluorosilicone oil, as a processing aid, can effectively adjust the crosslinking density of fluorosilicone rubber, thereby improving the mechanical properties of fluorosilicone rubber and solving the problem that traditional hydroxy fluorosilicone oil cannot increase the crosslinking density.

[0039] 3. Vinyl hydroxy fluorosilicone oil, as a processing aid, can effectively adjust the crosslinking density of fluorosilicone rubber, thereby improving the mechanical properties of fluorosilicone rubber and solving the problem that traditional hydroxy fluorosilicone oil cannot increase the crosslinking density. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] The present invention provides the following technical solution: a method for preparing vinyl hydroxy fluorosilicone oil.

[0042] The method comprises the following steps: using trifluoropropylmethylcyclotrisiloxane and a vinyl ring body as raw materials, adding a capping agent accounting for 0.001 to 10 g of the raw material mass, a cationic catalyst accounting for 0.001 to 2 g of the raw material mass, and a reaction auxiliary agent with a mass of 0.002 to 15 g, and performing a polymerization reaction at 30 to 60° C. for 0.5 to 8 h, until the viscosity of the reaction system is stable; the vinyl ring body is a methylvinylsiloxane ring body, and its mass in the raw material is 0.001 to 10, until the viscosity of the reaction system is stable; adding an alkaline compound to neutralize the reaction system to neutrality, then washing with water to remove salts, and finally decompressing and lowering to 120° C. and stopping to obtain vinyl hydroxy fluorosilicone oil; the capping agent is tetramethyl dihydroxy disiloxane and hydroxy fluorosilicone oil; the cationic catalyst is HCl solution, cationic Resin; auxiliary reaction agents are acetone and ethyl acetate; methyl vinyl siloxane ring bodies are trimethyltrivinylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and pentamethylpentavinylcyclopentasiloxane; vinyl hydroxy fluorosilicone oil is prepared by the above preparation method, and the viscosity of the vinyl hydroxy fluorosilicone oil is 31 to 809 mPa·s; vinyl hydroxy fluorosilicone oil is used as a structure control agent and processing aid for fluorosilicone rubber; the mechanical properties of fluorosilicone rubber include increased strength, improved resilience, and reduced permanent deformation at break; the mechanical properties of fluorosilicone rubber include increased strength, improved resilience, or reduced permanent deformation at break; vinyl hydroxy fluorosilicone oil is used alone as a structure control agent for fluorosilicone rubber, or together with hydroxy fluorosilicone oil as a structure control agent for fluorosilicone rubber.

[0043] The following six examples further illustrate the process parameters and effects of the present invention, each of which is carried out in a reactor equipped with a stirring, temperature control, and condensation device:

[0044] Example 1:

[0045] Raw materials and reagents: In a reactor equipped with a stirrer, thermometer, rotary evaporator and condenser, add 900g of trifluoropropylmethylcyclotrisiloxane, 3.6g of trimethyltrivinylcyclotrisiloxane, 600g of acetone, 24.2g of tetramethyldihydroxydisiloxane as the end-capping agent, and 1ml to 6ml of HCl solution.

[0046] Reaction process: When the stirring temperature reaches 35°C, add HCl solution, and the reaction temperature fluctuates within the range of 35-45°C. Maintain this reaction for 5 hours, and take samples to measure the viscosity according to the reaction situation. When the viscosity reaches stability, add about 16g of NaHCO3 solution and continue stirring for 1 hour to make the reaction system neutral.

[0047] Post-treatment: Add deionized water for washing, filter out acetone and water, and evacuate to a vacuum degree of -0.098 MPa before extracting low-boiling substances and maintain this for 3 hours.

[0048] Results: 860 g of vinyl hydroxy fluorosilicone oil was obtained with a yield of 91% and a product viscosity of 200 mPa·s.

[0049] Example 2:

[0050] Raw materials and reagents: Add 960g trifluoropropylmethylcyclotrisiloxane, 23g trimethyltrivinylcyclotrisiloxane, add cationic resin (dosage is 0.02%) at room temperature, and 17g hydroxyfluorosilicone oil as a capping agent.

[0051] Reaction process: The temperature is controlled within the range of 40-50°C, and this temperature is maintained for equilibrium reaction. Samples are taken to measure the viscosity according to the reaction conditions. When the viscosity reaches a stable state, acetone, water and cationic resin are filtered out.

[0052] Post-treatment: Heat to 110°C, evacuate to a vacuum degree of -0.096 MPa, and start extracting low-boiling substances, maintaining for 3 hours.

[0053] Results: 600 g of vinyl hydroxy fluorosilicone oil was obtained with a yield of 60% and a product viscosity of 31 mPa·s.

[0054] Example 3:

[0055] Raw materials and reagents: basically the same as in Example 2, except that the amount of the end-capping agent added was changed to 8 g.

[0056] Reaction and post-processing process: same as Example 2.

[0057] Results: 305 g of ethylene hydroxy fluorosilicone oil was obtained with a yield of 56% and a viscosity of 58 mPa·s.

[0058] Example 4

[0059] Raw materials and reagents: Add 810g trifluoropropylmethylcyclotrisiloxane and 11g trimethyltrivinylcyclotrisiloxane. When the temperature reaches 35°C, add HCl solution (1ml-6ml) and 8.5g capping agent (water).

[0060] Reaction process: The temperature is controlled in the range of 35-45°C and the reaction is carried out at this temperature. When the viscosity reaches a stable state, about 16g of NaHCO3 solution is added and stirring is continued for 1h to make the reaction system neutral.

[0061] Post-processing: The product is obtained after filtration and other operations.

[0062] Results: 907 g of transparent hydroxyl-terminated methyl vinyl fluorosilicone oil was obtained with a yield of 96% and a product viscosity of 562 mPa·s.

[0063] Example 5

[0064] Raw materials and reagents: Add 840g trifluoropropylmethylcyclotrisiloxane, 8g trimethyltrivinylcyclotrisiloxane, and 7g end-capping agent (hydroxyfluorosilicone oil), control the temperature within the range of 45-55°C, and add HCl solution (1ml-6ml).

[0065] Reaction process: Maintain this temperature for equilibrium reaction and observe the viscosity change of the reaction system. When the viscosity reaches stability, add about 16g of NaHCO3 solution and continue stirring for 1h to make the reaction system neutral.

[0066] Post-processing: Start extracting low-boiling substances when the vacuum reaches -0.098MPa, and stop when the temperature reaches 120℃.

[0067] Results: 840 g of vinyl hydroxy fluorosilicone oil was obtained with a yield of 97% and a product viscosity of 809 mPa·s.

[0068] Example 6

[0069] Raw materials and reagents: Add 450g trifluoropropylmethylcyclotrisiloxane, 7g D tetramethyltetravinylcyclotetrasiloxane, and 105g D3, and add HCl solution (1ml to 6ml) at a temperature of 45 to 55°C.

[0070] Reaction and post-treatment process: same as Example 5.

[0071] Results: 155 g of vinyl hydroxy fluorosilicone oil was obtained with a yield of 90% and a product viscosity of 150 mPa·s.

[0072] The vinyl content is precisely controllable: By adjusting the type and amount of the capping agent, the amount of vinyl ring added, and the reaction conditions, the vinyl content in the product can be precisely controlled, thereby flexibly adjusting the crosslinking density of the fluorosilicone rubber according to different needs, significantly improving the mechanical properties of the fluorosilicone rubber, such as increasing strength, improving resilience, and reducing permanent deformation at break, solving the problem that traditional hydroxyl fluorosilicone oil cannot effectively control the crosslinking density.

[0073] Low-temperature polymerization and low energy consumption: The polymerization reaction temperature is controlled at 30-60°C, which greatly reduces energy consumption compared to some high-temperature polymerization processes, meets the requirements of green chemistry and energy-saving production, and has significant economic and environmental benefits.

[0074] High fluorine content and product stability: Using trifluoropropylmethylcyclotrisiloxane as the primary raw material results in a product with a high fluorine content, endowing the fluorosilicone rubber with excellent oil and chemical resistance. Furthermore, by optimizing the reaction process and raw material ratio, the resulting vinyl hydroxy fluorosilicone oil is highly stable and offers reliable performance during storage and use.

[0075] Multifunctional application innovation: This product can not only be used alone as a structure control agent for fluorosilicone rubber, but can also be used in combination with hydroxyl fluorosilicone oil, and can be used as a special additive for silicone rubber, expanding its application range in the rubber field and providing more possibilities for improving the performance of rubber products.

[0076] The process is simple and efficient: The preparation process is relatively simple. Through reasonable raw material combination and reaction step design, high yield and high-quality products can be prepared without complex equipment and tedious operations, and it has good industrial application prospects.

[0077] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing vinyl hydroxy fluorosilicone oil, comprising: using trifluoropropyl methylcyclotrisiloxane and a vinyl ring body as raw materials, adding a capping agent (0.001 to 10 g by weight of the raw materials), a cationic catalyst (0.001 to 2 g by weight of the raw materials), and a reaction aid (0.002 to 15 g by weight); conducting a polymerization reaction at 30 to 60° C. for 0.5 to 8 hours, until the viscosity of the reaction system stabilizes; the vinyl ring body is a methylvinylsiloxane ring body, the mass of which in the raw materials is 0.001 to 10, until the viscosity of the reaction system stabilizes; adding an alkaline compound to neutralize the reaction system to neutrality, then washing with water to remove salts, and finally decompressing and degassing to 120° C. before stopping to obtain vinyl hydroxy fluorosilicone oil.

2. The method for preparing a vinyl hydroxy fluorosilicone oil according to claim 1, wherein: The end-capping agent is tetramethyldihydroxydisiloxane or hydroxyfluorosilicone oil.

3. The method for preparing a vinyl hydroxy fluorosilicone oil according to claim 1, wherein: The cationic catalyst is HCl solution or cationic resin.

4. The method for preparing a vinyl hydroxy fluorosilicone oil according to claim 1, wherein: The auxiliary reaction agent is acetone and ethyl acetate.

5. The method for preparing a vinyl hydroxy fluorosilicone oil according to claim 1, wherein: The methylvinylsiloxane ring body is trimethyltrivinylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, or pentamethylpentavinylcyclopentasiloxane.

6. A vinyl hydroxy fluorosilicone oil, characterized in that The vinyl hydroxy fluorosilicone oil is prepared by the preparation method according to any one of claims 1 to 5, and the viscosity of the vinyl hydroxy fluorosilicone oil is 31 to 809 mPa·s.

7. The method for preparing a vinyl hydroxy fluorosilicone oil according to claim 6, wherein: The vinyl hydroxy fluorosilicone oil is used as a structure control agent and processing aid for fluorosilicone rubber.

8. The method for preparing a vinyl hydroxy fluorosilicone oil according to claim 7, wherein: The mechanical properties of the fluorosilicone rubber include increasing the strength of the fluorosilicone rubber, improving the resilience, and reducing the permanent deformation at break.

9. The method for preparing a vinyl hydroxy fluorosilicone oil according to claim 8, wherein: The mechanical properties of the fluorosilicone rubber include increasing the strength of the fluorosilicone rubber, improving the resilience or reducing the permanent deformation at break.

10. The method for preparing a vinyl hydroxy fluorosilicone oil according to claim 7, wherein: The vinyl hydroxy fluorosilicone oil is used alone as a structure control agent for fluorosilicone rubber, or together with the hydroxy fluorosilicone oil, as a structure control agent for fluorosilicone rubber.