High-temperature-resistant silicon-boron dual-modified phenolic resin and preparation method thereof

Abstract

The invention relates to the technical field of phenolic resin preparation, in particular to high-temperature-resistant silicon-boron dual-modified phenolic resin and a preparation method thereof.The preparation method comprises the steps that firstly, specific silane, phenylboronic acid, a specific catalyst and ethyl alcohol are added into a reactor, after the reaction is completed, reduced pressure distillation is conducted to remove ethyl alcohol, and a boron-silicon modifier is obtained; 2, mixing a phenolic compound with a dehydrating agent, stirring, heating, sequentially adding a borosilicate modifier and a basic catalyst, adjusting the pH value, and carrying out a dehydration esterification reaction under a reduced pressure condition; 3, after the esterification reaction is finished, an aldehyde compound is added, stirring and heating are conducted, decompression dehydration and addition polycondensation reaction are conducted at the same time, and finally the boron-silicon modified phenolic resin is prepared. In the scheme, high-bond-energy boron-oxygen bonds and silicon-oxygen bonds are introduced into the phenolic resin, part of phenolic hydroxyl groups are blocked, the number of phenolic resin benzene rings is increased, and therefore the phenolic resin is prepared; the synthesized borosilicate phenolic resin has high residual carbon content and excellent high temperature resistance, ablation resistance and oxidation resistance, and has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of phenolic resin preparation, and in particular to a high-temperature resistant silicon-boron double-modified phenolic resin and a preparation method thereof. Background Art

[0002] Phenolic resin is an ablative-resistant polymer material formed by the polycondensation of phenols and aldehydes under the action of acidic or alkaline catalysts. Phenolic resin is widely used in many technical fields such as construction, transportation, electronics, aerospace, etc. as a variety of functional materials such as coatings, adhesives, and thermal insulation foams due to its excellent heat resistance, electrical insulation, good dimensional stability, and high mechanical strength. However, the phenolic hydroxyl groups in the molecular structure of phenolic resin are prone to oxidation and water absorption reactions, which affect its heat resistance and oxidation resistance, and limit its development in ablative-resistant materials. Therefore, chemically modifying the molecular structure of phenolic resin to improve its heat resistance and oxidation resistance has gradually become the main research direction for optimizing resin performance.

[0003] To improve the heat resistance of phenolic resin, the modification methods currently mainly include: 1. Introducing high bond energy BO bonds (774.04 kJ / mol), Si-O bonds (472.5 kJ / mol), Ti-O bonds (662 kJ / mol) and other metal covalent bonds that are greater than CC bonds (334.72 kJ / mol); 2. Adding aromatic (hetero) ring structures with stable molecular structures to improve their rigidity and thermal stability; 3. Using the high temperature resistance of resin oligomers or monomers such as bismaleimide and phthalonitrile to isolate or block some phenolic hydroxyl groups and improve heat resistance. However, the above-mentioned modification methods of high temperature resistant phenolic resins have improved the heat resistance temperature of the material to a certain extent, but due to the limitations of its structure and components, the improvement is limited, and its comprehensive performance still needs to be improved.

[0004] In contrast, the high-temperature resistant silicon-boron double-modified phenolic resin proposed in the present invention innovatively introduces two elements, silicon and boron, for synergistic modification. The silicon element can form a stable silicon-oxygen bond network structure in the resin system, effectively improving the thermal stability and oxidation resistance of the resin; the boron element can interact with the phenolic resin molecular chain, enhance the degree of cross-linking between molecules, and further improve the heat resistance of the resin. Compared with traditional modification methods, this double modification method can more significantly enhance the working performance of phenolic resin in high temperature environments. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a high temperature resistant silicon-boron double-modified phenolic resin and a preparation method thereof, thereby solving the technical problems mentioned in the background technology.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A method for preparing a high temperature resistant silicon-boron double-modified phenolic resin, characterized in that it comprises the following steps:

[0008] Step 1: preparing a borosilicate modifier by addition reaction, adding specific silane, 4-vinylbenzeneboric acid, a specific catalyst and ethanol into a reactor, reacting for 2-4.5 hours, and after the reaction is completed, removing ethanol by reduced pressure distillation to obtain a borosilicate modifier;

[0009] Step 2: Carry out esterification reaction, mix the phenolic compound with the dehydrating agent, stir evenly and heat to 80-130° C., add borosilicate modifier and alkaline catalyst sodium hydroxide in sequence, adjust the pH to 7.00-7.50, and carry out dehydration esterification reaction under reduced pressure for 1.5-3.5 hours;

[0010] Step 3: Perform addition polycondensation reaction. After the esterification reaction is completed, add aldehyde compounds, stir and heat to 110-130° C., and decompress and dehydrate at the same time, perform addition polycondensation reaction for 2-4 hours, and finally obtain borosilicate modified phenolic resin.

[0011] In a possible implementation, the specific silane is trimethoxysilane, triethoxysilane, bistrimethylsiloxymethylsilane, tributylsilane or tris(trimethylsiloxy)silane; the molar ratio of the specific silane to 4-vinylphenylboronic acid is 1:1-3; the specific catalyst is platinum (0)-1,3-diethene-1,1,3,3-tetramethyldisiloxane, chloroplatinic acid, and the mass ratio of the catalyst to phenylboric acid and silane is 1:5000.

[0012] In a possible implementation, in the addition reaction, the reaction temperature is 50-65°C.

[0013] In a possible implementation, the phenolic compound is phenol, methylphenol, naphthol, phenylphenol, resorcinol and hydroquinone, the dehydrating agent is toluene and benzene, the mass ratio of the phenolic compound to the dehydrating agent is 1:1-1.5; the molar ratio of the borosilicate modifier to the phenolic compound is 1:2-3; the molar ratio of the phenolic compound to sodium hydroxide is 1:0.01-0.03.

[0014] In a possible implementation, the aldehyde compound is formaldehyde solution, paraformaldehyde, trioxymethylene, acetaldehyde and salicylaldehyde, and the molar ratio of the phenolic compound to the aldehyde compound is 1:1.1-1.5.

[0015] In a possible implementation, the high temperature resistant borosilicate double-modified phenolic resin prepared by the high temperature resistant borosilicate double-modified phenolic resin preparation method, the structural formula of the borosilicate modifier is as follows:

[0016]

[0017] Among them, R is methyl, ethyl, butyl, or trimethylsilyl.

[0018] In a possible implementation, the high temperature resistant borosilicate modified phenolic resin prepared by the high temperature resistant silane modified phenolic resin preparation method has the following structural formula:

[0019]

[0020] Among them, n is 1-18, x is 1-20, and y is 1-15.

[0021] Beneficial effects compared with the prior art:

[0022] 1. In this scheme, by introducing high-bond-energy boron-oxygen bonds and silicon-oxygen bonds into phenolic resin, part of the phenolic hydroxyl groups are blocked, and the number of benzene rings in the phenolic resin is increased. The synthesized borosilicate phenolic resin has high residual carbon, excellent high temperature resistance, ablation resistance and oxidation resistance, and has broad application prospects;

[0023] 2. In this solution, the stability of the resin molecular structure is greatly enhanced under high temperature environment through the synergistic effect of silicon and boron elements. The presence of silicon-oxygen bonds effectively hinders the thermal degradation process of the molecular chain, and the cross-linked structure promoted by the boron element further improves the thermal stability of the resin. At high temperatures, the resin of the present invention can maintain a higher carbon content and maintain good structural integrity, thereby effectively extending the service life of the material in high-temperature component applications such as aerospace, improving the reliability and safety of equipment under high temperature conditions, and reducing the risk of failure caused by insufficient high temperature resistance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0025] Figure 1 Schematic diagram of the general reaction formula of the synthetic borosilicate modifier of the present invention;

[0026] Figure 2 It is a schematic diagram of the general reaction formula of synthesizing boron-silicon-modified phenolic resin of the present invention;

[0027] Figure 3 This is a schematic diagram of the GPC test results of the borosilicate modified phenolic resin of the present invention;

[0028] Figure 4 The present invention is a flow chart of the method for preparing borosilicate modified phenolic resin. DETAILED DESCRIPTION

[0029] The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be implemented in various forms, so the present invention is not limited to the embodiments described below. In addition, in order to more clearly describe the present invention, components that are not connected with the invention will be omitted from the drawings.

[0030] The technical solution in the embodiment of the present application is to solve the problems of the above-mentioned background technology, and the overall idea is as follows:

[0031] Embodiment 1:

[0032] This embodiment introduces a method for preparing a high temperature resistant silicon-boron double-modified phenolic resin, comprising the following steps:

[0033] Step 1: In a 1000mL four-necked flask that has been strictly cleaned and dried, accurately weigh 244.4g of trimethoxysilane, 295.94g of 4-vinylphenylboronic acid, 0.11g of platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane, and add 500mL of analytical pure ethanol. After installing the stirring device, thermometer and reflux condenser, start stirring and stabilize the stirring speed at 400 rpm to fully mix the reactants. Then, place the four-necked flask in a temperature-controllable heating jacket and heat it to 65°C at a slow rate of 2°C / min. During the entire reaction, the operator needs to pay attention to the changes in the thermometer reading at all times, and ensure that the reaction temperature is always maintained at a constant state of 65°C by fine-tuning the heating power. The reaction time is controlled to 3 hours. During this process, silane and phenylboronic acid undergo an addition reaction to generate a borosilicate modifier. The reaction equation is as follows:

[0034]

[0035] (where R = methyl)

[0036] After the reaction was completed, the reaction apparatus was quickly connected to a reduced pressure distillation system to remove ethanol at a constant temperature of 45°C and a vacuum degree of -0.09 MPa, ultimately obtaining 464.69 g of borosilicate modifier, with a yield of 85.6% after precise calculation.

[0037] Step 2: Add 150g of phenol and 172mL of toluene to another reactor equipped with a strong stirring and efficient distillation device that has also been pretreated, set the stirring speed to 350 rpm, stir evenly, and heat to 100°C at a heating rate of 3°C / min. Next, use a constant pressure dropping funnel to slowly add 430.65g of the prepared borosilicate modifier and 0.64g of sodium hydroxide, and the dropping process lasts for 35 minutes. Sodium hydroxide, as an alkaline catalyst, promotes the esterification reaction in the reaction. During the dropping process, the operator closely observes the situation in the reactor to prevent the reaction from being too violent due to excessive drop acceleration or excessive concentration of local reactants. After the dropwise addition is completed, the pH of the reaction system is carefully adjusted to 7.15 using a calibrated pH meter and sodium hydroxide or dilute hydrochloric acid solution. Then, the dehydration esterification reaction is carried out under reduced pressure conditions (vacuum degree -0.09MPa) for 1.5 hours, and the temperature is stabilized at 100°C by a temperature controller during the reaction. During the esterification reaction, a dedicated person records the temperature and pressure data every 15 minutes to ensure stable reaction conditions and promote full reaction between phenolic compounds and borosilicate modifiers to form intermediate products with specific structures and properties.

[0038] Step 3: After the esterification reaction is completed, add 159.56g of formaldehyde aqueous solution (36%) to the reactor, continue stirring and heat to 120°C at a heating rate of 4°C / min, while maintaining a reduced pressure dehydration state (vacuum degree -0.08MPa), and perform addition polycondensation for 2 hours. During the polycondensation reaction, formaldehyde reacts with the phenol intermediate containing the modified group, the molecular chain gradually grows and cross-links, and finally forms a borosilicate modified phenolic resin. The reaction equation is as follows:

[0039]

[0040] (Wherein, R = methyl, n = 1-18, x = 1-20, y = 1-15.)

[0041] During the reaction, the stirring speed was maintained at 300 rpm, and the changes in temperature and pressure were always noted to ensure the uniformity and sufficiency of the reaction. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain 351.00 g of borosilicate modified phenolic resin with a solid content of 85.44% and a residual carbon rate of 67.89% at 800°C.

[0042] Embodiment 2:

[0043] This embodiment is based on the first embodiment, the raw materials are changed, and a preparation method of a high temperature resistant silicon-boron double modified phenolic resin is introduced:

[0044] Step 1: Add 667.5g of bistrimethylsiloxymethylsilane, 443.91g of 4-vinylphenylboronic acid, 0.22g of chloroplatinic acid and 900mL of ethanol in a 1500mL four-necked flask. Turn on the stirring device and set the stirring speed to 500 rpm. After the reactants are fully mixed, the temperature is raised to 65°C at a heating rate of 3°C / min by the heating jacket, and the reaction is continued at this temperature for 3 hours. During this reaction, silane and phenylboronic acid react under the action of a catalyst to generate a borosilicate modifier. During the reaction, the temperature sensor and intelligent controller are used to control the stability of the reaction temperature so that the temperature fluctuation does not exceed ±0.3°C, so as to avoid excessive temperature fluctuations on the reaction rate and product quality. After the reaction is completed, ethanol is recovered by vacuum distillation, the distillation temperature is set to 50°C, and the vacuum degree is -0.09MPa. Finally, 889.13g of borosilicate modifier is obtained, and the yield is 87.2% after careful calculation.

[0045] Step 2: Take 200g of p-cresol and 229.36mL of toluene and place them in a reactor, set the stirring speed to 400 rpm, stir evenly, and heat to 90°C at a heating rate of 3°C / min. Then, 685.37g of borosilicate modifier and 0.74g of sodium hydroxide are slowly added dropwise by a peristaltic pump, wherein the amount of sodium hydroxide added is accurately calculated based on the molar ratio of phenolic compounds to sodium hydroxide, and the addition time is controlled at about 45 minutes. After the addition is completed, the pH is adjusted to 7.10 using a calibrated pH meter and sodium hydroxide or dilute hydrochloric acid solution, and then the esterification reaction is carried out under reduced pressure (vacuum degree -0.09MPa) for 3.5 hours, and the reaction temperature is maintained at 90°C during the reaction. During the esterification reaction, the temperature, vacuum degree and pH value of the reaction system are checked and recorded every 20 minutes to ensure that the reaction conditions meet the requirements, so that p-cresol and the borosilicate modifier react fully to form an esterification product.

[0046] Step 3: After the esterification reaction is completed, add 208.33g of paraformaldehyde solution (32%), stir and heat to 110°C at a heating rate of 4°C / min, and dehydrate under reduced pressure (vacuum degree -0.08MPa) to carry out addition polycondensation reaction for 2.5 hours. During the polycondensation reaction, paraformaldehyde reacts with the esterification product, and the molecular chain continues to grow and cross-link to form borosilicate modified phenolic resin. After the reaction is completed, after cooling and filtering operations, 571.22g of borosilicate modified phenolic resin is obtained, the solid content of which is 88.26%, and the residual carbon rate at 800°C is 69.70%.

[0047] Embodiment three:

[0048] Step 1: Add 164.28g triethoxysilane, 147.97g 4-vinylbenzeneboronic acid, 0.06g chloroplatinic acid and 300mL ethanol to a 1000mL four-necked flask, turn on the stirring device, adjust the stirring speed to 450 rpm, stir evenly, heat to 50°C in a water bath at a heating rate of 2°C / min, and react for 4 hours. In this addition reaction, ensure that the reactants are fully mixed, the reaction temperature and time are accurately controlled, and use a water bath and a high-precision thermometer to ensure that the temperature fluctuates within the range of ±0.4°C to ensure the synthesis quality of the borosilicate modifier. The reaction equation is as follows:

[0049]

[0050] (where R = ethyl)

[0051] After the reaction was completed, ethanol was removed by using a reduced pressure distillation apparatus at 60° C. and a vacuum degree of -0.08 MPa to obtain 249.80 g of borosilicate modifier, with a calculated yield of 83.5%.

[0052] Step 2: Add 100g of naphthol and 113.64mL of benzene to the reactor, set the stirring speed to 350 rpm, stir evenly, and heat to 100°C at a heating rate of 3°C / min. Then slowly add 215.45g of borosilicate modifier and 0.28g of sodium hydroxide through a separatory funnel, adjust the pH to 7.12, and carry out esterification reaction under reduced pressure (vacuum degree -0.09MPa) for 3.5 hours, and maintain the temperature at 100°C during the reaction. During the esterification reaction, check the reaction every 15 minutes to ensure that naphthol reacts effectively with the borosilicate modifier to generate an intermediate product with a specific structure.

[0053] Step 3: After the above reaction is completed, add 77.7g of paraformaldehyde solution (32%), stir and heat to 125°C at a heating rate of 4°C / min, and decompress and dehydrate (vacuum degree -0.08MPa) to carry out addition polycondensation reaction for 2.5 hours. During the polycondensation reaction, paraformaldehyde reacts with the naphthol intermediate containing the modified group to form 334.53g of borosilicate modified phenolic resin. After the reaction is completed, the borosilicate modified phenolic resin is obtained after fine treatment, and its solid content is 84.61%, and the residual carbon rate at 800°C is 67.46%.

[0054] Embodiment 4:

[0055] Step 1: In a 1200mL four-necked flask, add 325.6g tributylsilane, 343.12g 4-vinylphenylboronic acid, 0.13g platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane and 600mL ethanol. Turn on the stirring device and adjust the stirring speed to 500 rpm. After the reactants are fully mixed, heat the temperature to 55°C at a heating rate of 3°C / min and react for 4.5 hours. During the reaction, continue stirring and monitor the temperature in real time to ensure that silane and phenylboronic acid react smoothly to form a borosilicate modifier. The reaction equation is as follows:

[0056]

[0057] (where R = butyl)

[0058] After the reaction was completed, ethanol was removed by a vacuum distillation apparatus at 55° C. and a vacuum degree of -0.09 MPa to obtain 536.82 g of borosilicate modifier, with a yield of 86.3% after precise calculation.

[0059] Step 2: Mix 180g of phenylphenol and 207.36mL of benzene and stir evenly, set the stirring speed to 450 rpm, heat to 95°C, then add 483.14g of the borosilicate modifier prepared above and 0.81g of sodium hydroxide in sequence, adjust the pH to 7.18, and carry out esterification reaction under reduced pressure (vacuum degree -0.09MPa) for 2 hours, and maintain the temperature at 95°C during the reaction. During the esterification reaction, check and record the temperature, pressure and pH value of the reaction system every 20 minutes to ensure that the reaction conditions meet the requirements, so that the phenylphenol and the borosilicate modifier react fully to form an esterification product.

[0060] Step 3: After the above reaction is completed, add 192.45g of trioxymethylene, stir and heat to 115°C at a heating rate of 4°C / min, react for 3 hours, and dehydrate under reduced pressure (vacuum degree -0.08MPa) to finally obtain 428.67g of borosilicate modified phenolic resin. During the polycondensation reaction, trioxymethylene reacts with the esterification product, and the molecular chain grows and cross-links to form borosilicate modified phenolic resin. The product was tested for performance, and its solid content was 86.12%, and the residual carbon rate at 800°C was 68.34%.

[0061] Embodiment five:

[0062] Step 1: Place 287.3g tris(trimethylsiloxy)silane, 268.45g 4-vinylbenzeneboronic acid, 0.11g chloroplatinic acid and 450mL ethanol into a 1000mL reactor, turn on the stirring device, adjust the stirring speed to 450 rpm, stir evenly, heat to 60°C at a heating rate of 2°C / min, and react for 3.5 hours. In this step, ensure that the reactants are fully mixed and the reaction temperature is stable, and control the temperature fluctuation to not exceed ±0.4°C to facilitate the synthesis of the borosilicate modifier. The reaction equation is as follows:

[0063]

[0064] (where R = trimethylsilyl)

[0065] After the reaction was completed, ethanol was recovered by reduced pressure distillation at a distillation temperature of 50° C. and a vacuum degree of -0.08 MPa to obtain 423.78 g of borosilicate modifier with a calculated yield of 84.8%.

[0066] Step 2: First, 160g of resorcinol and 208mL of toluene were mixed and stirred evenly, the stirring speed was set to 400 rpm, and the mixture was heated to 105°C. 512.36g of borosilicate modifier and 0.72g of sodium hydroxide were added in sequence, the pH was adjusted to 7.16, and the esterification reaction was carried out under reduced pressure (vacuum degree -0.09MPa) for 2.5 hours, and the temperature was maintained at 105°C during the reaction. During the esterification reaction, the reaction was checked every 15 minutes to allow the resorcinol to fully react with the borosilicate modifier to generate a stable intermediate product.

[0067] Step 3: After the above reaction is completed, 176.54g of salicylaldehyde is added, stirred and heated to 128°C at a heating rate of 4°C / min, reacted for 4 hours, and simultaneously decompressed and dehydrated (vacuum degree -0.08MPa), and an addition polycondensation reaction is performed to obtain 489.32g of borosilicate modified phenolic resin. In the polycondensation reaction, salicylaldehyde reacts with the resorcinol intermediate product containing the modified group to form a borosilicate modified phenolic resin. The product is analyzed for various properties, and its solid content is 87.03%, and the residual carbon rate at 800°C is 69.11%.

[0068] Comparative Example:

[0069] 300g of phenol, 319.12g of formaldehyde aqueous solution (36%), 1.28g of sodium hydroxide, adjusted to pH 7.15, stirred at 350 rpm, heated to 120°C, reacted for 2 hours, and simultaneously dehydrated under reduced pressure (vacuum degree -0.09 to 0.10 MPa), and carried out addition polycondensation reaction to obtain 248.92g of phenolic resin. This comparative example was prepared according to a conventional phenolic resin synthesis method without introducing a borosilicate modifier, and its solid content was 77.82%, and the residual carbon rate at 800°C was 55.91%.

[0070] The test results of solid content and residual carbon rate of Examples 1 to 5 and the comparative example are as follows:

[0071] Table 1 Solid content and residual carbon rate of the embodiments and comparative examples

[0072] project Solid content (%) 800℃ residual carbon rate (%) Embodiment 1 85.44 67.89 Embodiment 2 88.26 69.70 Embodiment 3 84.61 67.46 Embodiment 4 86.12 68.34 Embodiment 5 87.03 69.11 Comparative Example 77.82 55.91

[0073] Compared with the comparative example, the solid contents of Examples 1 to 5 were increased by 7.62%, 10.44%, 6.79%, 8.30% and 9.21%, respectively, and the residual carbon rates were increased by 11.98%, 13.79%, 11.55%, 12.43% and 13.20%, respectively, indicating that the introduction of borosilicate modifier significantly enhanced the heat resistance and ablation resistance of phenolic resin.

[0074] Finally, it should be noted that: Obviously, the above embodiments are only examples for clearly explaining the present invention, and are not intended to limit the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the scope of protection of the present invention.

Claims

1. A method for preparing a high temperature resistant silicon-boron double-modified phenolic resin, characterized in that: The following steps are involved: Step 1: preparing a borosilicate modifier by addition reaction, adding specific silane, 4-vinylbenzeneboric acid, a specific catalyst and ethanol into a reactor, reacting for 2-4.5 hours, and after the reaction is completed, removing ethanol by reduced pressure distillation to obtain a borosilicate modifier; Step 2: Carry out esterification reaction, mix the phenolic compound with the dehydrating agent, stir evenly and heat to 80-130° C., add borosilicate modifier and alkaline catalyst sodium hydroxide in sequence, adjust the pH to 7.00-7.50, and carry out dehydration esterification reaction under reduced pressure for 1.5-3.5 hours; Step 3: Perform addition polycondensation reaction. After the esterification reaction is completed, add aldehyde compounds, stir and heat to 110-130° C., and decompress and dehydrate at the same time, perform addition polycondensation reaction for 2-4 hours, and finally obtain borosilicate modified phenolic resin.

2. The method for preparing a high temperature resistant silicon-boron double-modified phenolic resin according to claim 1, characterized in that: The specific silane is trimethoxysilane, triethoxysilane, bistrimethylsiloxymethylsilane, tributylsilane or tris(trimethylsiloxy)silane; the molar ratio of the specific silane to 4-vinylphenylboronic acid is 1:1-3; the specific catalyst is platinum (0)-1,3-diethene-1,1,3,3-tetramethyldisiloxane and chloroplatinic acid, and the mass ratio of the catalyst to phenylboric acid and silane is 1:5000.

3. A high temperature resistant silicon-boron double modified phenolic resin and a preparation method thereof as claimed in claim 1, characterized in that: In the addition reaction, the reaction temperature is 50-65°C.

4. The method for preparing a high temperature resistant silicon-boron double-modified phenolic resin according to claim 1, characterized in that: The phenolic compounds are phenol, methylphenol, naphthol, phenylphenol, resorcinol and hydroquinone, the dehydrating agents are toluene and benzene, the mass ratio of the phenolic compounds to the dehydrating agents is 1:1-1.5; the molar ratio of the borosilicate modifier to the phenolic compounds is 1:2-3; the molar ratio of the phenolic compounds to sodium hydroxide is 1:0.01-0.

03.

5. The method for preparing a high temperature resistant silicon-boron double-modified phenolic resin according to claim 1, characterized in that: The aldehyde compound is formaldehyde solution, paraformaldehyde, trioxymethylene, acetaldehyde and salicylaldehyde, and the molar ratio of the phenol compound to the aldehyde compound is 1:1.1-1.

5.

6. The high temperature resistant borosilicate double modified phenolic resin prepared by the method for preparing the high temperature resistant borosilicate double modified phenolic resin according to any one of claims 1 to 5, characterized in that: The structural formula of the borosilicate modifier is as follows: Among them, R is methyl, ethyl, butyl, or trimethylsilyl.

7. The high temperature resistant borosilicate modified phenolic resin prepared by the method for preparing a high temperature resistant silane modified phenolic resin according to any one of claims 1 to 5, characterized in that: The structural formula of the high temperature resistant borosilicate double modified phenolic resin is as follows: Among them, n is 1-18, x is 1-20, and y is 1-15.

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