Benzocyclobutene-modified phenyl silicone resin and preparation method thereof

Abstract

The present invention relates to the field of silicone resins, and in particular to a benzocyclobutene-modified phenyl silicone resin and a preparation method thereof, which are used to solve the problem that existing silicone resins have poor high-temperature resistance, ablation resistance and charring performance, which limits their application in high-temperature environments. The benzocyclobutene-modified phenyl silicone resin contains a large number of benzene rings, which imparts it with excellent high-temperature resistance. After the benzocyclobutene structure is introduced, its thermal stability is further improved. Moreover, its molecular structure also contains a large number of phosphorus-containing structures and nitrogen-containing structures, which enable it to form more carbon protective layers during combustion, thereby achieving the purpose of flame retardancy and ablation resistance. The benzocyclobutene-modified phenyl silicone resin has excellent high-temperature resistance, ablation resistance, flame retardancy and charring performance, and can be widely used in the fields of aerospace, electrical industry, semiconductor packaging, etc., and the preparation method is simple, easy to operate, and suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the field of silicone resins, and in particular to a benzocyclobutene-modified phenyl silicone resin and a preparation method thereof. Background Art

[0002] Currently, silicone resins are widely used in various industrial fields such as coatings, seals, and insulation materials due to their excellent chemical stability and mechanical properties. Traditional silicone resins are generally composed of siloxane monomers through condensation or addition polymerization and have relatively fixed structures and properties. However, although these traditional silicone resins exhibit good thermal stability to a certain extent, they are prone to chemical degradation reactions under extremely high temperature or high-speed airflow conditions, resulting in ablation, resulting in reduced material performance and even cracking and shedding. In addition, it is difficult to form a stable protective char layer, which limits their application in high-temperature environments.

[0003] Therefore, it is of great significance to develop a benzocyclobutene-modified phenyl silicone resin and a preparation method thereof that can significantly improve the high temperature resistance, ablation resistance and charring performance of silicone resin. Summary of the Invention

[0004] In order to overcome the above technical problems, the purpose of the present invention is to provide a benzocyclobutene-modified phenyl silicone resin and a preparation method thereof, which solves the problem that the existing silicone resin has poor high temperature resistance, ablation resistance and charring performance, which limits its application in high temperature environments.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a benzocyclobutene-modified phenyl silicone resin comprises the following steps:

[0007] Step s1: Add benzocyclobutene, iodine and acetic acid solution to a three-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, stir and react for 20-30 minutes at a temperature of -5-0°C and a stirring rate of 300-400 r / min, then add liquid bromine solution dropwise while stirring, and control the dropping rate to 1-2 drops / s. After the dropwise addition is completed, continue stirring and react for 40-50 hours. After the reaction is completed, pour the reaction product into distilled water, and then extract with petroleum ether 2-3 times. Combine the extracts and wash with saturated sodium sulfite solution, saturated sodium carbonate solution and distilled water 2-3 times in sequence, and then dry with anhydrous sodium sulfate. After vacuum filtration, the filtrate is rotary evaporated to remove the solvent to obtain an intermediate product;

[0008] Step s2: magnesium powder, iodine and tetrahydrofuran are added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen is introduced for protection. The mixture is stirred at a temperature of 25-30°C and a stirring rate of 300-400 r / min for 20-30 minutes, and then the intermediate product solution is added dropwise while stirring, and the dropping rate is controlled to 1-2 drops / s. After the addition is completed, the mixture is heated to reflux and the stirring reaction is continued for 1-2 hours. The mixture is then cooled to 25-30°C and dimethoxymethylsilyl chloride is added and the stirring reaction is continued for 20-30 minutes. The mixture is then heated to reflux and the stirring reaction is continued for 6-8 hours. After the reaction is completed, the reaction product is cooled to room temperature, and then the solvent is removed by rotary evaporation. Petroleum ether is then used as an eluent for silica gel column chromatography to obtain a benzocyclobutene monomer.

[0009] Step s3: DOPO, vinyltrimethoxysilane, azobisisobutyronitrile, and diethylene glycol dimethyl ether were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at a temperature of 25-30° C. and a stirring rate of 300-400 r / min for 10-15 minutes. The mixture was then heated to 80-85° C. and stirred for 20-30 hours. After the reaction, the reaction product was cooled to room temperature, and then rotary evaporated to remove the solvent. The product was then added to cyclohexane, and vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a flame retardant monomer.

[0010] Step s4: adding pentaerythritol, mercaptopropionic acid, p-toluenesulfonic acid, and cyclohexane to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, stirring the mixture at a temperature of 25-30° C. and a stirring rate of 300-400 rpm for 10-15 minutes, then raising the temperature to reflux and continuing the stirring reaction for 6-8 hours. After the reaction is completed, the reaction product is rotary evaporated to remove the solvent to obtain a thiol crosslinking agent;

[0011] Step s5: Add diphenyldimethoxysilane, benzocyclobutene monomer, flame retardant monomer, γ-aminoethylaminopropyltrimethoxysilane, vinyltrimethoxysilane, anhydrous ethanol and deionized water to a three-necked flask equipped with a stirrer, a thermometer and an air duct, introduce nitrogen protection, and stir the reaction for 10-15 minutes at a temperature of 25-30°C and a stirring rate of 300-400r / min. Then, adjust the pH to 4-5 with hydrochloric acid solution, and then continue to stir the reaction at 35-40°C for 3-4 hours. Then, add a thiol crosslinking agent and stir the reaction at 65-70°C for 3-4 hours. After the reaction, cool the reaction product to room temperature, and then adjust the pH to 7 with sodium hydroxide solution. Then, rotary evaporation is used to remove the solvent to obtain benzocyclobutene-modified phenyl silicone resin.

[0012] As a further embodiment of the present invention, the benzocyclobutene, iodine, acetic acid solution and liquid bromine solution in step s1 are used in a ratio of 10 mmol: 0.01-0.03 g: 15-20 mL: 5-7 mL.

[0013] As a further solution of the present invention: the liquid bromine solution in step s1 is a solution formed by dissolving liquid bromine in acetic acid solution at a ratio of 11-15 mmol:5 mL; the mass fraction of the acetic acid solution is 95%.

[0014] As a further embodiment of the present invention, the magnesium powder, iodine, tetrahydrofuran, intermediate product solution and dimethoxymethylsilyl chloride in step s2 are used in a ratio of 13-17 mmol: 0.01-0.03 g: 30-40 mL: 20-25 mL: 10 mmol.

[0015] As a further solution of the present invention: the intermediate product solution in step s2 is a solution formed by dissolving the intermediate product in tetrahydrofuran at a ratio of 11-13 mmol:20 mL.

[0016] As a further embodiment of the present invention, the usage ratio of DOPO, vinyltrimethoxysilane, azobisisobutyronitrile and diethylene glycol dimethyl ether in step s3 is 10 mmol: 10 mmol: 0.02-0.04 g: 40-50 mL.

[0017] As a further solution of the present invention: the usage ratio of the pentaerythritol, mercaptopropionic acid, p-toluenesulfonic acid and cyclohexane in step s4 is 10 mmol: 45-50 mmol: 0.05-0.1 g: 50-60 mL.

[0018] As a further embodiment of the present invention: the diphenyldimethoxysilane, benzocyclobutene monomer, flame retardant monomer, γ-aminoethylaminopropyltrimethoxysilane, vinyltrimethoxysilane, anhydrous ethanol, deionized water and mercapto crosslinking agent in step s5 are used in a ratio of 70-80 mmol: 28-44 mmol: 12-18 mmol: 5-9 mmol: 2-6 mmol: 30-40 mL: 60-70 mL: 2-8 mmol.

[0019] As a further solution of the present invention: the mass fraction of the hydrochloric acid solution in step s5 is 15-20%; the mass fraction of the sodium hydroxide solution is 25-30%.

[0020] As a further solution of the present invention: the benzocyclobutene-modified phenyl silicone resin is prepared according to the preparation method of the benzocyclobutene-modified phenyl silicone resin.

[0021] Beneficial effects of the present invention:

[0022] The invention discloses a benzocyclobutene-modified phenyl silicone resin and a preparation method thereof. First, benzocyclobutene and liquid bromine are reacted, and the liquid bromine is used as a brominating agent to introduce bromine atoms into the benzene ring of the benzocyclobutene to obtain an intermediate product. Then, a Grignard reaction is performed to react the intermediate product with dimethoxymethylchlorosilane, so that the bromine atoms on the intermediate product are converted into a dimethoxymethylsilane structure to obtain a benzocyclobutene monomer. Then, DOPO and vinyltrimethoxysilane are reacted, and the PH on DOPO reacts with the alkenyl on the vinyltrimethoxysilane to obtain a flame retardant. The monomer is then reacted with pentaerythritol and mercaptopropionic acid, and the hydroxyl groups on the pentaerythritol and the carboxyl groups on the mercaptopropionic acid undergo an esterification reaction to introduce a large number of mercapto groups to obtain a mercapto crosslinking agent. Finally, diphenyldimethoxysilane, benzocyclobutene monomer, flame retardant monomer, γ-aminoethylaminopropyltrimethoxysilane, and vinyltrimethoxysilane are used as polymerization monomers to form a silicone resin. The mercapto groups of the mercapto crosslinking agent react with the alkenyl groups in the silicone resin to form a complex crosslinking network, thereby greatly improving its stability to obtain a benzocyclobutene-modified phenyl silicone resin.

[0023] The benzocyclobutene modified phenyl silicone resin contains a large number of benzene rings, which gives it excellent high temperature resistance. After the introduction of the benzocyclobutene structure, the benzocyclobutene can form a polymer with a cross-linked network structure due to its unique thermal ring-opening polymerization mechanism, which further improves its thermal stability. In addition, the molecular structure of the benzocyclobutene modified phenyl silicone resin also contains a large number of phosphorus-containing structures and nitrogen-containing structures. The phosphorus-containing molecules will generate strong acids such as metaphosphoric acid and polymetaphosphoric acid when burned, which promotes the formation of a carbon layer in the condensed phase to isolate heat exchange. The nitrogen-containing molecules will form a carbon layer in the condensed phase to isolate heat exchange. When decomposing at high temperatures, a large amount of non-combustible gas is produced, which can dilute the oxygen concentration near the flame and form a protective layer when heated, resulting in an increase in pyrolytic carbon and an improvement in the carbon's oxidation resistance. The enhanced carbon oxidation resistance can retain more carbon and effectively block the transfer of heat, achieving the purpose of flame retardancy and ablation resistance. The benzocyclobutene-modified phenyl silicone resin has excellent high-temperature resistance, ablation resistance, flame retardancy and carbon-forming properties, and can be widely used in aerospace, electrical industry, semiconductor packaging and other fields. In addition, the preparation method is simple, easy to operate, and suitable for industrial production. DETAILED DESCRIPTION

[0024] 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 any creative efforts shall fall within the scope of protection of the present invention.

[0025] Example 1:

[0026] This embodiment is a method for preparing a benzocyclobutene-modified phenyl silicone resin, comprising the following steps:

[0027] Step s1: 10 mmol of benzocyclobutene, 0.01 g of iodine and 15 mL of 95% acetic acid solution were added to a three-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, and the mixture was stirred for 20 minutes at a temperature of -5°C and a stirring rate of 300 r / min. Then, 5 mL of liquid bromine was added dropwise while stirring, which was prepared by dissolving 11 mmol:5 mL of liquid bromine in 95% acetic acid solution. The dropping rate was controlled to be 1 drop / s. After the addition was completed, the stirring reaction was continued for 40 hours. After the reaction was completed, the reaction product was poured into distilled water, and then extracted twice with petroleum ether. The extracts were combined and washed twice with saturated sodium sulfite solution, saturated sodium carbonate solution and distilled water in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain an intermediate product.

[0028] Step s2: 13 mmol magnesium powder, 0.01 g iodine and 30 mL tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 25° C. and a stirring rate of 300 r / min for 20 min. Then, 20 mL of the intermediate product was added dropwise while stirring, and the intermediate product solution formed by dissolving the intermediate product in tetrahydrofuran at a ratio of 11 mmol:20 mL was added dropwise. The dropping rate was controlled to 1 drop / s. After the addition was completed, the mixture was heated to reflux and continued to stir for 1 h. The mixture was then cooled to 25° C. and 10 mmol dimethoxymethylsilyl chloride was added and continued to stir for 20 min. The mixture was then heated to reflux and continued to stir for 6 h. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. Petroleum ether was then used as an eluent for silica gel column chromatography to obtain a benzocyclobutene monomer.

[0029] Step s3: 10 mmol DOPO, 10 mmol vinyltrimethoxysilane, 0.02 g azobisisobutyronitrile, and 40 mL diethylene glycol dimethyl ether were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at 25° C. and a stirring rate of 300 r / min for 10 min. The mixture was then heated to 80° C. and stirred for 20 h. After the reaction, the reaction product was cooled to room temperature, and then rotary evaporated to remove the solvent. The product was then added to cyclohexane, and vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a flame retardant monomer.

[0030] Step s4: 10 mmol of pentaerythritol, 45 mmol of mercaptopropionic acid, 0.05 g of p-toluenesulfonic acid, and 50 mL of cyclohexane were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser. The mixture was stirred at 25° C. and a stirring rate of 300 r / min for 10 minutes. The mixture was then heated to reflux and stirred for 6 hours. After the reaction, the reaction product was rotary evaporated to remove the solvent to obtain a thiol crosslinking agent.

[0031] Step s5: 70mmol diphenyldimethoxysilane, 28mmol benzocyclobutene monomer, 12mmol flame retardant monomer, 5mmolγ-aminoethylaminopropyltrimethoxysilane, 2mmol vinyltrimethoxysilane, 30mL anhydrous ethanol and 60mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred and reacted for 10 minutes at a temperature of 25°C and a stirring rate of 300r / min. After that, the pH was adjusted to 4 with a 15% mass fraction hydrochloric acid solution, and then the temperature was raised to 35°C and the stirring reaction was continued for 3h. After that, 2mmol of thiol crosslinking agent was added and the temperature was raised to 65°C and the stirring reaction was continued for 3h. After the reaction, the reaction product was cooled to room temperature, and then the pH was adjusted to 7 with a 25% mass fraction sodium hydroxide solution. The solvent was then removed by rotary evaporation to obtain benzocyclobutene-modified phenyl silicone resin.

[0032] Example 2:

[0033] This embodiment is a method for preparing a benzocyclobutene-modified phenyl silicone resin, comprising the following steps:

[0034] Step s1: 10 mmol of benzocyclobutene, 0.02 g of iodine and 18 mL of 95% acetic acid solution were added to a three-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, and stirred for 25 minutes at a temperature of -3°C and a stirring rate of 350 r / min. Then, 6 mL of liquid bromine was added dropwise while stirring, which was prepared by dissolving 13 mmol:5 mL of liquid bromine in 95% acetic acid solution. The dropping rate was controlled to be 1 drop / s. After the addition was completed, the stirring reaction was continued for 45 hours. After the reaction was completed, the reaction product was poured into distilled water, and then extracted twice with petroleum ether. The extracts were combined and washed twice with saturated sodium sulfite solution, saturated sodium carbonate solution and distilled water in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain an intermediate product.

[0035] Step s2: 15mmol magnesium powder, 0.02g iodine and 35mL tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The reaction was stirred at a temperature of 28°C and a stirring rate of 350r / min for 25min, and then 22mL of the intermediate product was added dropwise while stirring. The intermediate product solution formed by dissolving 12mmol:20mL of the intermediate product in tetrahydrofuran was added dropwise, and the dropping rate was controlled to be 1 drop / s. After the addition was completed, the temperature was raised to reflux and the reaction was continued with stirring for 1.5h. The temperature was then lowered to 28°C and 10mmol of dimethoxymethylsilyl chloride was added and the reaction was continued with stirring for 28min. The temperature was then raised to reflux and the reaction was continued with stirring for 7h. After the reaction was completed, the reaction product was cooled to room temperature, and the solvent was removed by rotary evaporation. Petroleum ether was then used as an eluent for silica gel column chromatography to obtain benzocyclobutene monomer;

[0036] Step s3: 10 mmol DOPO, 10 mmol vinyltrimethoxysilane, 0.03 g azobisisobutyronitrile, and 45 mL diethylene glycol dimethyl ether were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at 28° C. and a stirring rate of 350 r / min for 12 min. The mixture was then heated to 82° C. and stirred for 25 h. After the reaction, the reaction product was cooled to room temperature, and then rotary evaporated to remove the solvent. The product was then added to cyclohexane, and vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a flame retardant monomer.

[0037] Step s4: 10 mmol of pentaerythritol, 48 mmol of mercaptopropionic acid, 0.08 g of p-toluenesulfonic acid, and 55 mL of cyclohexane were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser. The mixture was stirred at 28° C. and a stirring rate of 350 r / min for 12 minutes. The mixture was then heated to reflux and stirred for 7 hours. After the reaction, the reaction product was rotary evaporated to remove the solvent to obtain a thiol crosslinking agent.

[0038] Step s5: 75mmol diphenyldimethoxysilane, 36mmol benzocyclobutene monomer, 15mmol flame retardant monomer, 7mmol γ-aminoethylaminopropyltrimethoxysilane, 4mmol vinyltrimethoxysilane, 35mL anhydrous ethanol and 65mL deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The reaction was stirred at a temperature of 28°C and a stirring rate of 350r / min for 12 minutes, and then the pH was adjusted to 4.5 with a hydrochloric acid solution with a mass fraction of 18%. The stirring reaction was continued at 38°C for 3.5h. Then, 5mmol of thiol crosslinking agent was added and the temperature was raised to 68°C and the reaction was stirred for 3.5h. After the reaction, the reaction product was cooled to room temperature, and then the pH was adjusted to 7 with a sodium hydroxide solution with a mass fraction of 28%. The solvent was then removed by rotary evaporation to obtain benzocyclobutene-modified phenyl silicone resin.

[0039] Example 3:

[0040] This embodiment is a method for preparing a benzocyclobutene-modified phenyl silicone resin, comprising the following steps:

[0041] Step s1: 10 mmol of benzocyclobutene, 0.03 g of iodine and 20 mL of 95% acetic acid solution were added to a three-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, and the mixture was stirred for 30 minutes at a temperature of 0°C and a stirring rate of 400 r / min. Then, 7 mL of liquid bromine was added dropwise while stirring, which was prepared by dissolving 15 mmol:5 mL of liquid bromine in 95% acetic acid solution. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the stirring reaction was continued for 50 hours. After the reaction was completed, the reaction product was poured into distilled water, and then extracted with petroleum ether for 3 times. The extracts were combined and washed with saturated sodium sulfite solution, saturated sodium carbonate solution and distilled water for 3 times in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain an intermediate product.

[0042] Step s2: 17 mmol magnesium powder, 0.03 g iodine and 40 mL tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 30 minutes. Then, 25 mL of the intermediate product was added dropwise while stirring, and the intermediate product solution formed by dissolving the intermediate product in tetrahydrofuran at a ratio of 13 mmol:20 mL was added dropwise. The dropping rate was controlled to 2 drops / s. After the addition was completed, the mixture was heated to reflux and continued to stir for 2 hours. The mixture was then cooled to 30° C. and 10 mmol dimethoxymethylsilyl chloride was added and continued to stir for 30 minutes. The mixture was then heated to reflux and continued to stir for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. Petroleum ether was then used as an eluent for silica gel column chromatography to obtain a benzocyclobutene monomer.

[0043] Step s3: 10 mmol DOPO, 10 mmol vinyltrimethoxysilane, 0.04 g azobisisobutyronitrile, and 50 mL diethylene glycol dimethyl ether were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at 30° C. and a stirring rate of 400 r / min for 15 min. The mixture was then heated to 85° C. and stirred for 30 h. After the reaction, the reaction product was cooled to room temperature, and then rotary evaporated to remove the solvent. The product was then added to cyclohexane, and vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a flame retardant monomer.

[0044] Step s4: 10 mmol of pentaerythritol, 50 mmol of mercaptopropionic acid, 0.1 g of p-toluenesulfonic acid, and 60 mL of cyclohexane were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at 30° C. and a stirring rate of 400 rpm for 15 minutes. The mixture was then heated to reflux and stirred for 8 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent to obtain a thiol crosslinking agent.

[0045] Step s5: 80mmol of diphenyldimethoxysilane, 44mmol of benzocyclobutene monomer, 18mmol of flame retardant monomer, 9mmol of γ-aminoethylaminopropyltrimethoxysilane, 6mmol of vinyltrimethoxysilane, 40mL of anhydrous ethanol and 70mL of deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred and reacted for 15 minutes at a temperature of 30°C and a stirring rate of 400r / min. After that, the pH was adjusted to 5 with a 20% by mass hydrochloric acid solution, and then the temperature was raised to 40°C and the stirring reaction was continued for 4 hours. After that, 8mmol of thiol crosslinking agent was added and the temperature was raised to 70°C and the stirring reaction was continued for 4 hours. After the reaction, the reaction product was cooled to room temperature, and then the pH was adjusted to 7 with a 30% by mass sodium hydroxide solution. The solvent was then removed by rotary evaporation to obtain benzocyclobutene-modified phenyl silicone resin.

[0046] Comparative Example 1:

[0047] This comparative example is a preparation method of a benzocyclobutene-modified phenyl silicone resin, comprising the following steps:

[0048] 80 mmol of diphenyldimethoxysilane, 40 mL of anhydrous ethanol and 70 mL of deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The reaction was stirred at a temperature of 30°C and a stirring rate of 400 r / min for 15 minutes. Then, the pH was adjusted to 5 with a 20% mass fraction hydrochloric acid solution, and then the temperature was raised to 40°C and the stirring reaction was continued for 4 hours. Then, the temperature was raised to 70°C and the stirring reaction was continued for 4 hours. After the reaction, the reaction product was cooled to room temperature, and then the pH was adjusted to 7 with a 30% mass fraction sodium hydroxide solution. The solvent was then removed by rotary evaporation to obtain a phenyl silicone resin.

[0049] Comparative Example 2:

[0050] This comparative example is a preparation method of a benzocyclobutene-modified phenyl silicone resin, comprising the following steps:

[0051] Step s1: 10 mmol of benzocyclobutene, 0.03 g of iodine and 20 mL of 95% acetic acid solution were added to a three-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, and the mixture was stirred for 30 minutes at a temperature of 0°C and a stirring rate of 400 r / min. Then, 7 mL of liquid bromine was added dropwise while stirring, which was prepared by dissolving 15 mmol:5 mL of liquid bromine in 95% acetic acid solution. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the stirring reaction was continued for 50 hours. After the reaction was completed, the reaction product was poured into distilled water, and then extracted with petroleum ether for 3 times. The extracts were combined and washed with saturated sodium sulfite solution, saturated sodium carbonate solution and distilled water for 3 times in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain an intermediate product.

[0052] Step s2: 17 mmol magnesium powder, 0.03 g iodine and 40 mL tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 30 minutes. Then, 25 mL of the intermediate product was added dropwise while stirring, and the intermediate product solution formed by dissolving the intermediate product in tetrahydrofuran at a ratio of 13 mmol:20 mL was added dropwise. The dropping rate was controlled to 2 drops / s. After the addition was completed, the mixture was heated to reflux and continued to stir for 2 hours. The mixture was then cooled to 30° C. and 10 mmol dimethoxymethylsilyl chloride was added and continued to stir for 30 minutes. The mixture was then heated to reflux and continued to stir for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. Petroleum ether was then used as an eluent for silica gel column chromatography to obtain a benzocyclobutene monomer.

[0053] Step s3: 80 mmol of diphenyldimethoxysilane, 44 mmol of benzocyclobutene monomer, 40 mL of anhydrous ethanol and 70 mL of deionized water were added to a three-necked flask equipped with an agitator, a thermometer and an air duct, and nitrogen was introduced for protection. The reaction was stirred at a temperature of 30°C and a stirring rate of 400 r / min for 15 minutes. Then, the pH was adjusted to 5 with a 20% mass fraction hydrochloric acid solution, and then the temperature was raised to 40°C and the stirring reaction was continued for 4 hours. Then, the temperature was raised to 70°C and the stirring reaction was continued for 4 hours. After the reaction, the reaction product was cooled to room temperature, and then the pH was adjusted to 7 with a 30% mass fraction sodium hydroxide solution. The solvent was then removed by rotary evaporation to obtain a benzocyclobutene-modified phenyl silicone resin.

[0054] Comparative Example 3:

[0055] This comparative example is a preparation method of a benzocyclobutene-modified phenyl silicone resin, comprising the following steps:

[0056] Step s1: 10 mmol of benzocyclobutene, 0.03 g of iodine and 20 mL of 95% acetic acid solution were added to a three-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, and the mixture was stirred for 30 minutes at a temperature of 0°C and a stirring rate of 400 r / min. Then, 7 mL of liquid bromine was added dropwise while stirring, which was prepared by dissolving 15 mmol:5 mL of liquid bromine in 95% acetic acid solution. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the stirring reaction was continued for 50 hours. After the reaction was completed, the reaction product was poured into distilled water, and then extracted with petroleum ether for 3 times. The extracts were combined and washed with saturated sodium sulfite solution, saturated sodium carbonate solution and distilled water for 3 times in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain an intermediate product.

[0057] Step s2: 17 mmol magnesium powder, 0.03 g iodine and 40 mL tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 30 minutes. Then, 25 mL of the intermediate product was added dropwise while stirring, and the intermediate product solution formed by dissolving the intermediate product in tetrahydrofuran at a ratio of 13 mmol:20 mL was added dropwise. The dropping rate was controlled to 2 drops / s. After the addition was completed, the mixture was heated to reflux and continued to stir for 2 hours. The mixture was then cooled to 30° C. and 10 mmol dimethoxymethylsilyl chloride was added and continued to stir for 30 minutes. The mixture was then heated to reflux and continued to stir for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. Petroleum ether was then used as an eluent for silica gel column chromatography to obtain a benzocyclobutene monomer.

[0058] Step s3: 80 mmol of diphenyldimethoxysilane, 44 mmol of benzocyclobutene monomer, 9 mmol of γ-aminoethylaminopropyltrimethoxysilane, 6 mmol of vinyltrimethoxysilane, 40 mL of anhydrous ethanol and 70 mL of deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred and reacted for 15 minutes at a temperature of 30°C and a stirring rate of 400 r / min. After that, the pH was adjusted to 5 with a 20% by mass hydrochloric acid solution, and then the temperature was raised to 40°C and the stirring reaction was continued for 4 hours. After that, the temperature was raised to 70°C and the stirring reaction was continued for 4 hours. After the reaction, the reaction product was cooled to room temperature, and then the pH was adjusted to 7 with a 30% by mass sodium hydroxide solution. The solvent was then removed by rotary evaporation to obtain a benzocyclobutene-modified phenyl silicone resin.

[0059] Comparative Example 4:

[0060] This comparative example is a preparation method of a benzocyclobutene-modified phenyl silicone resin, comprising the following steps:

[0061] Step s1: 10 mmol of benzocyclobutene, 0.03 g of iodine and 20 mL of 95% acetic acid solution were added to a three-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, and the mixture was stirred for 30 minutes at a temperature of 0°C and a stirring rate of 400 r / min. Then, 7 mL of liquid bromine was added dropwise while stirring, which was prepared by dissolving 15 mmol:5 mL of liquid bromine in 95% acetic acid solution. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the stirring reaction was continued for 50 hours. After the reaction was completed, the reaction product was poured into distilled water, and then extracted with petroleum ether for 3 times. The extracts were combined and washed with saturated sodium sulfite solution, saturated sodium carbonate solution and distilled water for 3 times in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain an intermediate product.

[0062] Step s2: 17 mmol magnesium powder, 0.03 g iodine and 40 mL tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 30 minutes. Then, 25 mL of the intermediate product was added dropwise while stirring, and the intermediate product solution formed by dissolving the intermediate product in tetrahydrofuran at a ratio of 13 mmol:20 mL was added dropwise. The dropping rate was controlled to 2 drops / s. After the addition was completed, the mixture was heated to reflux and continued to stir for 2 hours. The mixture was then cooled to 30° C. and 10 mmol dimethoxymethylsilyl chloride was added and continued to stir for 30 minutes. The mixture was then heated to reflux and continued to stir for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. Petroleum ether was then used as an eluent for silica gel column chromatography to obtain a benzocyclobutene monomer.

[0063] Step s3: 10 mmol DOPO, 10 mmol vinyltrimethoxysilane, 0.04 g azobisisobutyronitrile, and 50 mL diethylene glycol dimethyl ether were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser, and stirred at 30° C. and a stirring rate of 400 r / min for 15 min. The mixture was then heated to 85° C. and stirred for 30 h. After the reaction, the reaction product was cooled to room temperature, and then rotary evaporated to remove the solvent. The product was then added to cyclohexane, and vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a flame retardant monomer.

[0064] Step s4: 80 mmol of diphenyldimethoxysilane, 44 mmol of benzocyclobutene monomer, 18 mmol of flame retardant monomer, 9 mmol of γ-aminoethylaminopropyltrimethoxysilane, 40 mL of anhydrous ethanol and 70 mL of deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred and reacted for 15 minutes at a temperature of 30°C and a stirring rate of 400 r / min. After that, the pH was adjusted to 5 with a 20% by mass hydrochloric acid solution, and then the temperature was raised to 40°C and the stirring reaction was continued for 4 hours. After that, the temperature was raised to 70°C and the stirring reaction was continued for 4 hours. After the reaction was completed, the reaction product was cooled to room temperature, and then the pH was adjusted to 7 with a 30% by mass sodium hydroxide solution. The solvent was then removed by rotary evaporation to obtain a benzocyclobutene-modified phenyl silicone resin.

[0065] Comparative Example 5:

[0066] This comparative example is a preparation method of a benzocyclobutene-modified phenyl silicone resin, comprising the following steps:

[0067] Step s1: 10 mmol of benzocyclobutene, 0.03 g of iodine and 20 mL of 95% acetic acid solution were added to a three-necked flask equipped with a stirrer, a thermometer and a constant pressure dropping funnel, and the mixture was stirred for 30 minutes at a temperature of 0°C and a stirring rate of 400 r / min. Then, 7 mL of liquid bromine was added dropwise while stirring, which was prepared by dissolving 15 mmol:5 mL of liquid bromine in 95% acetic acid solution. The dropping rate was controlled to be 2 drops / s. After the addition was completed, the stirring reaction was continued for 50 hours. After the reaction was completed, the reaction product was poured into distilled water, and then extracted with petroleum ether for 3 times. The extracts were combined and washed with saturated sodium sulfite solution, saturated sodium carbonate solution and distilled water for 3 times in sequence, and then dried over anhydrous sodium sulfate. After vacuum filtration, the filtrate was rotary evaporated to remove the solvent to obtain an intermediate product.

[0068] Step s2: 17 mmol magnesium powder, 0.03 g iodine and 40 mL tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 30° C. and a stirring rate of 400 r / min for 30 minutes. Then, 25 mL of the intermediate product was added dropwise while stirring, and the intermediate product solution formed by dissolving the intermediate product in tetrahydrofuran at a ratio of 13 mmol:20 mL was added dropwise. The dropping rate was controlled to 2 drops / s. After the addition was completed, the mixture was heated to reflux and continued to stir for 2 hours. The mixture was then cooled to 30° C. and 10 mmol dimethoxymethylsilyl chloride was added and continued to stir for 30 minutes. The mixture was then heated to reflux and continued to stir for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature, and then the solvent was removed by rotary evaporation. Petroleum ether was then used as an eluent for silica gel column chromatography to obtain a benzocyclobutene monomer.

[0069] Step s3: 10 mmol of pentaerythritol, 50 mmol of mercaptopropionic acid, 0.1 g of p-toluenesulfonic acid, and 60 mL of cyclohexane were added to a three-necked flask equipped with a stirrer, a thermometer, and a reflux condenser. The mixture was stirred at 30° C. and a stirring rate of 400 rpm for 15 minutes. The mixture was then heated to reflux and stirred for 8 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent to obtain a mercapto crosslinking agent.

[0070] Step s4: 80 mmol of diphenyldimethoxysilane, 44 mmol of benzocyclobutene monomer, 6 mmol of vinyltrimethoxysilane, 40 mL of anhydrous ethanol and 70 mL of deionized water were added to a three-necked flask equipped with a stirrer, a thermometer and an air duct, and nitrogen was introduced for protection. The mixture was stirred and reacted for 15 minutes at a temperature of 30°C and a stirring rate of 400 r / min. After that, the pH was adjusted to 5 with a 20% mass fraction hydrochloric acid solution, and then the temperature was raised to 40°C and the stirring reaction was continued for 4 hours. Then, 8 mmol of a thiol crosslinker was added and the temperature was raised to 70°C and the stirring reaction was continued for 4 hours. After the reaction, the reaction product was cooled to room temperature, and then the pH was adjusted to 7 with a 30% mass fraction sodium hydroxide solution. The solvent was then removed by rotary evaporation to obtain a benzocyclobutene-modified phenyl silicone resin.

[0071] The properties of the benzocyclobutene-modified phenyl silicone resins of Examples 1-3 and Comparative Examples 1-5 were tested in the following manner:

[0072] Benzocyclobutene-modified phenyl silicone resin and DY-HMQ102 hydrogenated MQ silicone resin were mixed in a mass ratio of 9:1, and then 20 ppm of Karstedt catalyst was added to the total mass. The mixture was continued to be mixed until evenly mixed and poured into a mold. The mixture was heat treated at 120°C for 1 hour, and the bubbles were removed by vacuum. The temperature was then continued to be raised and heat treated at 180°C for 1 hour. The performance was tested after curing.

[0073] The test results are shown in the following table:

[0074] sample <![CDATA[T 5% ,℃]]> Linear ablation rate, mm / s Residual weight, % LOI, % Example 1 515 0.017 81.59 45.9 Example 2 527 0.015 83.04 46.6 Example 3 540 0.012 84.33 47.5 Comparative Example 1 372 0.063 64.25 29.1 Comparative Example 2 447 0.028 70.56 39.2 Comparative Example 3 402 0.034 67.28 35.3 Comparative Example 4 496 0.021 80.89 43.6 Comparative Example 5 478 0.024 77.05 40.9

[0075] Referring to the data in the above table, it can be seen that the benzocyclobutene-modified phenyl silicone resin of the present application has excellent high temperature resistance, ablation resistance and excellent char-forming property.

[0076] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0077] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a benzocyclobutene-modified phenyl silicone resin, characterized in that: The following steps are involved: Step s1: stirring benzocyclobutene, iodine, and acetic acid solution to react, then adding liquid bromine solution dropwise while stirring, continuing to stir the reaction after the addition is complete, pouring the reaction product into distilled water, and then extracting, washing and drying the extract, and then vacuum filtering, and rotary evaporating the filtrate to obtain an intermediate product; Step s2: stirring magnesium powder, iodine, and tetrahydrofuran for reaction, then adding the intermediate product solution dropwise while stirring, continuing to stir the reaction after the addition is complete, then adding dimethoxymethylsilyl chloride and continuing to stir the reaction, and after the reaction is complete, cooling the reaction product, then rotary evaporating it, and then performing silica gel column chromatography to obtain benzocyclobutene monomer; Step s3: stirring DOPO, vinyltrimethoxysilane, azobisisobutyronitrile, and diethylene glycol dimethyl ether to react. After the reaction, the reaction product is cooled, then rotary evaporated, and then added to cyclohexane. After vacuum filtration, the filtrate is rotary evaporated to obtain a flame retardant monomer. Step s4: stirring pentaerythritol, mercaptopropionic acid, p-toluenesulfonic acid and cyclohexane to react, and after the reaction is completed, rotary evaporating the reaction product to obtain a mercapto crosslinking agent; Step s5: diphenyldimethoxysilane, benzocyclobutene monomer, flame retardant monomer, γ-aminoethylaminopropyltrimethoxysilane, vinyltrimethoxysilane, anhydrous ethanol and deionized water are stirred for reaction, and then the pH is adjusted with hydrochloric acid solution, and then a thiol crosslinking agent is added and the stirring reaction is continued. After the reaction is completed, the reaction product is cooled, and then the pH is adjusted with sodium hydroxide solution, and then rotary evaporated to obtain a benzocyclobutene-modified phenyl silicone resin; the amount ratio of the diphenyldimethoxysilane, benzocyclobutene monomer, flame retardant monomer, γ-aminoethylaminopropyltrimethoxysilane, vinyltrimethoxysilane, anhydrous ethanol, deionized water and thiol crosslinking agent is 70-80mmol:28-44mmol:12-18mmol:5-9mmol:2-6mmol:30-40mL:60-70mL:2-8mmol.

2. The method for preparing a benzocyclobutene-modified phenyl silicone resin according to claim 1, wherein: The usage ratio of the benzocyclobutene, iodine, acetic acid solution and liquid bromine solution in step s1 is 10 mmol: 0.01-0.03 g: 15-20 mL: 5-7 mL.

3. The method for preparing a benzocyclobutene-modified phenyl silicone resin according to claim 1, wherein: The liquid bromine solution in step s1 is a solution formed by dissolving liquid bromine in acetic acid solution at a ratio of 11-15 mmol:5 mL; the mass fraction of the acetic acid solution is 95%.

4. The method for preparing a benzocyclobutene-modified phenyl silicone resin according to claim 1, wherein: The usage ratio of the magnesium powder, iodine, tetrahydrofuran, intermediate product solution and dimethoxymethylchlorosilane in step s2 is 13-17 mmol: 0.01-0.03 g: 30-40 mL: 20-25 mL: 10 mmol.

5. The method for preparing a benzocyclobutene-modified phenyl silicone resin according to claim 1, wherein: The intermediate product solution in step s2 is a solution formed by dissolving the intermediate product in tetrahydrofuran at a ratio of 11-13 mmol:20 mL.

6. The method for preparing a benzocyclobutene-modified phenyl silicone resin according to claim 1, wherein: The usage ratio of the DOPO, vinyltrimethoxysilane, azobisisobutyronitrile and diethylene glycol dimethyl ether in step s3 is 10 mmol: 10 mmol: 0.02-0.04 g: 40-50 mL.

7. The method for preparing a benzocyclobutene-modified phenyl silicone resin according to claim 1, wherein: The usage ratio of the pentaerythritol, mercaptopropionic acid, p-toluenesulfonic acid and cyclohexane in step s4 is 10 mmol: 45-50 mmol: 0.05-0.1 g: 50-60 mL.

8. The method for preparing a benzocyclobutene-modified phenyl silicone resin according to claim 1, wherein: The mass fraction of the hydrochloric acid solution in step s5 is 15-20%; the mass fraction of the sodium hydroxide solution is 25-30%.

9. A benzocyclobutene-modified phenyl silicone resin, characterized in that: The benzocyclobutene-modified phenyl silicone resin is prepared according to the preparation method of the benzocyclobutene-modified phenyl silicone resin according to any one of claims 1 to 8.