Preparation method of phosphorus-silicon synergistic grafting type high-temperature and low-temperature impact-resistant flame-retardant resin

Abstract

The invention discloses a preparation method of phosphorus-silicon synergistic grafting type flame-retardant resin resistant to high and low temperature impact. The preparation method comprises the following steps: (1) preparing a product DOPO-DAPEG from DOPO and DAPEG; (2) carrying out a reaction on the product DOPO-DAPE and APE (Aminopropyltriethoxysilane), so as to prepare a product DOPO-DAPE-APE; (3) the product DOPO-DAPE-APE and gamma-mercaptopropyltrimethoxysilane are subjected to a reaction under the action of a photoinitiator and under the irradiation of ultraviolet light, and a silane end-capped product is prepared; and (4) reacting the silane end-capped product with allyl glycidyl ether to obtain the phosphorus-silicon synergistic grafting type high and low temperature impact-resistant flame-retardant resin. According to the method, phosphorus and silicon elements are grafted into a resin molecular chain through chemical bonds, efficient flame retardance is achieved through the phosphorus-silicon synergistic effect, and meanwhile the high and low temperature impact resistance is improved by introducing a flexible chain segment. The limit oxygen index of the product is greater than or equal to 32%, the vertical combustion grade reaches UL94 V-0 grade, the mechanical property retention rate is greater than or equal to 90% after 50 times of high and low temperature circulation at-40 DEG C to 120 DEG C, and the terminal epoxy group endows the product with good reaction activity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional polymer materials, and specifically relates to a preparation method of a phosphorus-silicon synergistic grafted high and low temperature impact resistant flame-retardant resin. The resin prepared by the method has excellent flame-retardant performance and high and low temperature impact resistance, and can be widely applied to fields such as electronic packaging, rail transportation, aerospace and other fields with strict requirements for material safety and environmental adaptability. BACKGROUND

[0002] With the development of modern industry towards high-end and extreme, the performance requirements of polymer materials in complex service environments are increasing. Especially in the fields of electronics, electrical appliances, aerospace and other fields, materials not only need to have reliable flame-retardant performance to meet safety standards, but also need to withstand the impact caused by extreme temperature cycles to avoid structural damage or performance degradation due to thermal expansion and cold contraction.

[0003] Traditional flame-retardant resins mostly use additive flame retardants, such as bromine, magnesium hydroxide, etc. Although they can achieve basic flame-retardant effect, they have problems such as poor compatibility with the matrix, easy migration and precipitation, and mechanical property degradation, and it is difficult to simultaneously meet the requirements of high and low temperature impact resistance. The reaction type flame-retardant resin introduces flame-retardant elements into the molecular chain through chemical bonds, which improves the compatibility and durability, but the synergistic effect of single flame-retardant element such as only containing phosphorus or only containing silicon is insufficient, which makes it difficult to balance the flame-retardant efficiency and environmental stability.

[0004] In the prior art, a nitrogen-phosphorus-silicon tetra-functional epoxy resin is disclosed in Chinese patent document CN119875305B, wherein the nitrogen-phosphorus-silicon tetra-functional epoxy resin is prepared by condensation, addition and other reactions of various raw materials, forming a nitrogen-phosphorus-silicon synergistic flame-retardant system, but the high and low temperature impact resistance is poor due to high crosslinking density. In the Chinese patent document CN115678912B, a polyurethane toughened epoxy resin is used, which improves the low temperature toughness but significantly reduces the high temperature resistance, and the toughening agent has poor compatibility with the resin matrix.

[0005] The phosphorus-silicon synergistic flame-retardant system is concerned because of its "gas phase-condensed phase" dual flame-retardant mechanism: phosphorus elements can promote the formation of carbon layer during combustion, and silicon elements can enhance the carbon layer density and inhibit the release of smoke. However, the existing phosphorus-silicon flame-retardant resin is mostly random copolymer or simple blending structure, with low grafting efficiency and uneven distribution of silicon elements in the molecular chain, which leads to insufficient flexibility of molecular chain segments under high and low temperature impact, and easy cracking. In addition, some preparation methods have problems such as harsh reaction conditions, high toxicity of catalyst, and difficulty in product purification, which limits their industrial application.

[0006] Therefore, it is a research focus in the field of functional materials to develop a high and low temperature impact resistant flame-retardant resin with significant phosphorus-silicon synergistic effect and green controllable preparation process. SUMMARY

[0007] To address the challenges of balancing flame retardant efficiency and high / low temperature impact resistance in existing flame-retardant resins, as well as the complexity of their preparation processes, this invention aims to provide a phosphorus-silicon synergistic grafted high / low temperature impact resistant flame-retardant resin and its preparation method. By precisely controlling the grafting reaction process, a regular structure of "phosphorus flame-retardant unit - flexible segment - silane crosslinking unit" is constructed. The synergistic effect of phosphorus and silicon enhances the flame retardant performance, while the synergistic optimization of the flexible segment and crosslinking structure improves the material's high / low temperature impact resistance.

[0008] To achieve the above-mentioned objectives, the preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin provided by the present invention includes the following steps: (1) Dissolve 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and polyethylene glycol diallyl ether (DAPEG) in solvents respectively. Under nitrogen protection and a temperature of 100-130°C, add the initiator di-tert-butyl peroxide to the DOPO solution, and then slowly add the DAPEG solution dropwise, allowing DOPO and DAPEG to react in a molar ratio of 1:1.1-1.2. After the addition is complete, continue to react fully under nitrogen protection and a temperature of 100-130°C. After the reaction is complete, remove the unreacted DAPEG first, and then remove the solvent to obtain the product DOPO-DAPEG. The DAPEG solution is added dropwise over 1.5-2 hours, and the reaction time is 4-6 hours. Unreacted DAPEG can be removed through a semi-permeable membrane, and the solvent can be removed by distillation at a temperature of 60-80℃ and a pressure of -0.08 to -0.09 MPa. The amount of solvent used should be sufficient to completely dissolve the solute. To improve the flowability of the system and ensure a more complete reaction, the amount of solvent is generally equal to the mass of the dissolved solute.

[0009] (2) Under nitrogen protection and at a temperature of 20-40℃, pentaerythritol triallyl ether (APE) is slowly added dropwise to the product DOPO-DAPEG. Using phosphazene base as a catalyst, the product DOPO-DAPEG and APE are reacted in a molar ratio of 1.0-1.1:1. After the addition is complete, the reaction is continued under nitrogen protection and at a temperature of 20-40℃ until the reaction is complete. The product DOPO-DAPEG-APE is obtained. The addition time is generally 1-1.5h, and the reaction time after addition is 2-3h. (3) The product DOPO-DAPEG-APE and γ-mercaptopropyltrimethoxysilane (KH590) were mixed with the photoinitiator 2,2-dimethoxy-2-phenylacetophenone (BDK) and the antioxidant in a molar ratio of 1:2. The mixture was then subjected to a full reaction under ultraviolet light irradiation at 365 nm and a temperature of 15-40 °C. After the reaction was completed, 2,2-dimethoxy-2-phenylacetophenone was removed to obtain the silane-terminated product. The reaction time was 1-2 h. (4) Mix the silane-terminated product, initiator benzoyl peroxide, chain growth control agent 2,4-diphenyl-4-methyl-1-pentene, and solvent. Under nitrogen protection at 70-90℃, add allyl glycidyl ether dropwise at a molar ratio of 1-1.05:1 between the silane-terminated product and allyl glycidyl ether. After the addition is complete, continue the reaction under nitrogen protection at 70-90℃ until the reaction is complete. After the reaction is complete, remove the solvent to obtain a phosphorus-silicon synergistic grafted high and low temperature impact resistant flame retardant resin. The dropwise addition time is 20-30 min, and the reaction time is 3-6 h. The solvent can be removed by distillation at 50-60℃ and a pressure of -0.08 to -0.09 MPa. The amount of solvent used should be limited to completely dissolving the dissolved solute. Considering the need to improve the flow properties of the system and make the reaction more complete, the amount of solvent is generally equal to the mass of the silane-terminated product.

[0010] In step (1), the number average molecular weight of DAPEG is 400~1000, preferably 600~800.

[0011] In step (1), the amount of di-tert-butyl peroxide is 1.5% to 3% of the total mass of DOPO and DAPEG, preferably 2.0% to 2.5%.

[0012] In step (2), the phosphazene base is one or a mixture of two of t-BuP2 and t-BuP4 in any mass ratio, and the amount used is 0.8% to 1.5% of the total mass of DOPO-DAPEG and APE, preferably t-BuP4.

[0013] In step (3), the amount of 2,2-dimethoxy-2-phenylacetophenone is 0.5% to 1% of the total mass of DOPO-DAPEG-APE and γ-mercaptopropyltrimethoxysilane, preferably 0.6% to 0.8% of the total mass of DOPO-DAPEG-APE and γ-mercaptopropyltrimethoxysilane.

[0014] In step (3), the intensity of ultraviolet light irradiation is 5~10mW / cm², preferably 8~10mW / cm².

[0015] In step (3), the antioxidant is antioxidant 1010, and the amount used is 0.1%-0.3% of the total mass of DOPO-DAPEG-APE and γ-mercaptopropyltrimethoxysilane, preferably 0.2%-0.3%.

[0016] In step (3), the photoinitiator 2,2-dimethoxy-2-phenylacetophenone is removed by silica gel column chromatography.

[0017] In step (1), the solvent is any one of dimethylformamide and dimethylacetamide or a mixture of two of them in any mass ratio; in step (4), the solvent is any one of toluene, xylene, and propylene glycol methyl ether or a mixture of two or more of them in any mass ratio, with xylene being the preferred solvent.

[0018] In step (4), the amount of benzoyl peroxide used is 0.2% to 2.0% of the total mass of the silane-terminated product and allyl glycidyl ether, and the amount of the chain growth control agent 2,4-diphenyl-4-methyl-1-pentene used is 0.2% to 1.0% of the total mass of the silane-terminated product and allyl glycidyl ether.

[0019] The present invention has the following beneficial effects: This invention utilizes a multi-step chemical reaction to stably graft phosphorus and silicon elements into the resin molecular chain via chemical bonds, avoiding the precipitation problem of traditional additive flame retardants and improving compatibility and durability. The synergistic effect of phosphorus and silicon significantly enhances flame retardant performance, optimizing the insufficient synergistic effect of single flame retardant elements and solving the problem of balancing flame retardant efficiency and environmental stability. γ-mercaptopropyltrimethoxysilane is grafted into the molecular structure via a mercapto-olefin radical addition reaction, increasing the char yield and density of char residue during combustion, thereby enhancing the thermal stability and flame retardancy of the epoxy resin, while also suppressing smoke and reducing toxicity. The flexible polyethylene glycol diallyl ether segments introduced into the resin molecular structure effectively alleviate internal stress under high and low temperature impacts, giving the material excellent resistance to high and low temperature impacts. The epoxy groups at the resin terminals possess good reactivity and can be cross-linked and cured into a three-dimensional network structure under the action of a curing agent, increasing the cross-linking density and improving the material strength. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention. Example 1

[0021] (1) Dissolve 43.2g of DOPO in 43.2g of dimethylacetamide and 144g of DAPEG (number average molecular weight 600) in 144g of dimethylacetamide. Add the DOPO solution to a four-necked flask equipped with a constant pressure dropping funnel, condenser, stirrer, thermometer and nitrogen inlet tube. Purge the air with nitrogen three times. Add 4.3g of di-tert-butyl peroxide. Turn on the stirrer and condenser, mix evenly and raise the temperature to 120℃. Put the DAPEG solution into the constant pressure dropping funnel and slowly add it dropwise to the four-necked flask. Add the solution dropwise for 2 hours. After the addition is completed, continue the reaction for 5 hours. After the reaction is completed, remove the unreacted product DAPEG through a semi-permeable membrane. Remove the dimethylacetamide by vacuum distillation under a pressure of -0.09MPa and a temperature of 80℃ to obtain the product DOPO-DAPEG. (2) Add 81.6g of product DOPO-DAPEG to a four-necked flask, purge the air with nitrogen three times, turn on the stirrer, heat to 35℃, and slowly add the mixture of APE25.6 and 1.1g of phosphazene base t-BuP4 from the constant pressure dropping funnel to the four-necked flask for 1h. After the addition is complete, continue the reaction for 2h to obtain product DOPO-DAPEG-APE. (3) 107.2 g (0.1 mol) of product DOPO-DAPEG-APE was added to a UV reactor, along with 47.6 g of γ-mercaptopropyltrimethoxysilane, 1.23 g of BDK, and 0.31 g of antioxidant 1010. After stirring evenly, the mixture was reacted for 1.5 h under UV light irradiation at a wavelength of 365 nm and an intensity of 8 mW / cm² at a temperature of 25 °C. After the reaction was completed, the residual BDK was removed by silica gel column chromatography to obtain the product, which is the silane-terminated product. (4) Add 154.8 g of silane-terminated product, 154.8 g of xylene, 1.6 g of benzoyl peroxide, and 1.6 g of 2,4-diphenyl-4-methyl-1-pentene to a four-necked flask. Turn on the stirrer, introduce cooling water, and purge the air with nitrogen three times. After heating to 85°C, slowly add 11.4 g of allyl glycidyl ether, which is placed in a constant pressure dropping funnel, to the four-necked flask. The addition takes 30 min, and the reaction continues for 5 h after the addition is complete. After the reaction is complete, remove xylene by vacuum distillation under a pressure of -0.09 MPa and a temperature of 60°C to obtain a phosphorus-silicon synergistic grafted high and low temperature impact resistant flame retardant resin. Example 2

[0022] (1) Dissolve 43.2g of DOPO in 43.2g of dimethylacetamide and 132g of DAPEG (number average molecular weight 600) in 132g of dimethylacetamide. Add the DOPO solution to a four-necked flask equipped with a constant pressure dropping funnel, condenser, stirrer, thermometer and nitrogen inlet tube. Purge the air with nitrogen three times. Add 4.3g of di-tert-butyl peroxide. Turn on the stirrer and condenser, mix evenly and raise the temperature to 120℃. Put the DAPEG solution into the constant pressure dropping funnel and slowly add it dropwise to the four-necked flask. Add the solution dropwise for 2 hours. After the addition is completed, continue the reaction for 5 hours. After the reaction is completed, remove the unreacted product DAPEG through a semi-permeable membrane. Remove the dimethylacetamide by vacuum distillation under a pressure of -0.09MPa and a temperature of 80℃ to obtain the product DOPO-DAPEG. (2) Add 81.6g of product DOPO-DAPEG to a four-necked flask, purge the air with nitrogen three times, turn on the stirrer, heat to 35℃, and slowly add the mixture of APE25.6 and 1.1g of phosphazene base t-BuP2 from the constant pressure dropping funnel to the four-necked flask for 1h. After the addition is complete, continue the reaction for 2h to obtain product DOPO-DAPEG-APE. (3) 107.2 g (0.1 mol) of product DOPO-DAPEG-APE was added to a UV reactor, along with 47.6 g of γ-mercaptopropyltrimethoxysilane, 1.23 g of BDK, and 0.31 g of antioxidant 1010. After stirring evenly, the mixture was reacted for 1.5 h under UV light irradiation at a wavelength of 365 nm and an intensity of 8 mW / cm² at a temperature of 25 °C. After the reaction was completed, residual BDK was removed by silica gel column chromatography to obtain the product, which is the silane-terminated product. (4) Add 154.8 g of silane-terminated product, 154.8 g of propylene glycol methyl ether, 1.6 g of benzoyl peroxide, and 1.6 g of 2,4-diphenyl-4-methyl-1-pentene to a four-necked flask. Turn on the stirrer, introduce cooling water, and purge the air with nitrogen three times. After heating to 85°C, slowly add 10.9 g of allyl glycidyl ether, which is placed in a constant pressure dropping funnel, to the four-necked flask. The addition takes 30 min, and the reaction continues for 5 h after the addition is complete. After the reaction is complete, remove the propylene glycol methyl ether by vacuum distillation under a pressure of -0.09 MPa and a temperature of 65°C to obtain a phosphorus-silicon synergistic grafted high and low temperature impact resistant flame retardant resin. Example 3

[0023] (1) Dissolve 43.2g of DOPO in 43.2g of dimethylacetamide and 132g of DAPEG (number average molecular weight 600) in 132g of dimethylacetamide. Add the DOPO solution to a four-necked flask equipped with a constant pressure dropping funnel, condenser, stirrer, thermometer and nitrogen inlet tube. Purge the air with nitrogen three times. Add 3.74g of di-tert-butyl peroxide. Turn on the stirrer and condenser, mix evenly and raise the temperature to 110℃. Put the DAPEG solution into the constant pressure dropping funnel and slowly add it dropwise to the four-necked flask. Add the solution dropwise for 2 hours. After the addition is completed, continue the reaction for 5 hours. After the reaction is completed, remove the unreacted product DAPEG through a semi-permeable membrane. Remove the dimethylacetamide by vacuum distillation under a pressure of -0.09MPa and a temperature of 80℃ to obtain the product DOPO-DAPEG. (2) Add 81.6g of product DOPO-DAPEG to a four-necked flask, purge the air with nitrogen three times, turn on the stirrer, heat to 35°C, and slowly add the mixture of APE28.1 and 1.1g of phosphazene base t-BuP4 from the constant pressure dropping funnel to the four-necked flask for 1h. After the addition is complete, continue the reaction for 2h to obtain product DOPO-DAPEG-APE. (3) 107.2 g (0.1 mol) of product DOPO-DAPEG-APE was added to a UV reactor, along with 47.6 g of γ-mercaptopropyltrimethoxysilane, 1.23 g of BDK, and 0.31 g of antioxidant 1010. After stirring evenly, the mixture was reacted for 1.5 h under UV light irradiation at a wavelength of 365 nm and an intensity of 8 mW / cm² at a temperature of 25 °C. After the reaction was completed, residual BDK was removed by silica gel column chromatography to obtain the product, which is the silane-terminated product. (4) Add 154.8 g of silane-terminated product, 154.8 g of propylene glycol methyl ether, 1.6 g of benzoyl peroxide, and 1.6 g of 2,4-diphenyl-4-methyl-1-pentene to the above four-necked flask. Turn on the stirrer, introduce cooling water, and purge the air with nitrogen three times. After heating to 85°C, slowly add 11.4 g of allyl glycidyl ether, which is placed in a constant pressure dropping funnel, to the four-necked flask. The addition takes 30 min, and the reaction continues for 5 h after the addition is completed. After the reaction is completed, remove the propylene glycol methyl ether by vacuum distillation under a pressure of -0.09 MPa and a temperature of 55°C to obtain a phosphorus-silicon synergistic grafted high and low temperature impact resistant flame retardant resin. Example 4

[0024] (1) Dissolve 43.2g of DOPO in 43.2g of dimethylacetamide and 144g of DAPEG (number average molecular weight 600) in 144g of dimethylacetamide. Add the DOPO solution to a four-necked flask equipped with a constant pressure dropping funnel, condenser, stirrer, thermometer and nitrogen inlet tube. Purge the air with nitrogen three times. Add 3.74g of di-tert-butyl peroxide. Turn on the stirrer and condenser, mix evenly and raise the temperature to 110℃. Put the DAPEG solution into the constant pressure dropping funnel and slowly add it dropwise to the four-necked flask. Add the solution dropwise for 2 hours. After the addition is completed, continue the reaction for 5 hours. After the reaction is completed, remove the unreacted product DAPEG through a semi-permeable membrane. Remove the dimethylacetamide by vacuum distillation under pressure of -0.09MPa and temperature of 80℃ to obtain the product DOPO-DAPEG. (2) Add 81.6 g of product DOPO-DAPEG to the above four-necked flask, purge the air with nitrogen three times, turn on the stirrer, heat to 35°C, and slowly add the mixture of APE28.1.6 and 1.1 g of phosphazene base t-BuP2 into the four-necked flask from the constant pressure dropping funnel for 1 h. After the addition is complete, continue the reaction for 2 h to obtain product DOPO-DAPEG-APE. (3) 107.2g of product DOPO-DAPEG-APE was added to a UV reactor, along with 47.6g of γ-mercaptopropyltrimethoxysilane, 1.23g of BDK, and 0.31g of antioxidant 1010. After stirring evenly, the mixture was reacted for 1.5h under UV light irradiation at a wavelength of 365nm and an intensity of 8mW / cm² at a temperature of 25℃. After the reaction was completed, residual BDK was removed by silica gel column chromatography to obtain the product, which is the silane-terminated product. (4) Add 154.8 g of silane-terminated product, 154.8 g of xylene, 1.6 g of benzoyl peroxide, and 1.6 g of 2,4-diphenyl-4-methyl-1-pentene to the above four-necked flask. Turn on the stirrer, introduce cooling water, and purge the air with nitrogen three times. After heating to 85°C, slowly add 10.9 g of allyl glycidyl ether, which is placed in a constant pressure dropping funnel, to the four-necked flask. The addition takes 30 min, and the reaction continues for 5 h after the addition is completed. After the reaction is completed, remove xylene by vacuum distillation under a pressure of -0.09 MPa and a temperature of 60°C to obtain a phosphorus-silicon synergistic grafted high and low temperature impact resistant flame retardant resin. Comparative Example 1

[0025] (1) The steps are the same as those in step (1) of Example 1; (2) The steps are the same as those in step (2) of Example 1; (3) Replace γ-mercaptopropyltrimethoxysilane in step (3) of Example 1 with dodecyl mercaptothiol, which has a molecular weight close to that of γ-mercaptopropyltrimethoxysilane, and the rest are the same as step (3) of Example 1. (4) The steps are the same as those in step (4) of Example 1; A resin containing phosphorus but without silicon was produced. Comparative Example 2

[0026] (1) Use diethyl ethoxymethylene malonate, which has a molecular weight close to that of DOPO, instead of DOPO in step (1) of Example 1, and the rest of the steps are the same as those in step (1) of Example 1; (2) The steps are the same as those in step (2) of Example 1; (3) The steps are the same as those in step (3) of Example 1; (4) The steps are the same as those in step (4) of Example 1; A resin containing silicon but free of phosphorus was prepared. Comparative Example 3

[0027] DOPO 21.6g, γ-mercaptopropyltrimethoxysilane 47.6g and epoxy resin (E51) 210g were directly mechanically mixed to prepare a physically blended phosphorus-silicon flame retardant material.

[0028] The matrix resins prepared in all the above examples and comparative examples were cured completely with diethylenetriamine at room temperature, and the performance was tested according to the following standards. The test results are shown in Table 1.

[0029] High and low temperature cycling tensile strength retention rate: According to standard GB / T 2423.22-2012, after 50 cycles of -40℃×2h→120℃×2h, the tensile strength was tested and the retention rate was calculated; Low-temperature impact strength: Tested at -40℃ according to standard GB / T 1843-2008; High-temperature creep deformation: The creep deformation after 100 hours at 180℃ and 10MPa pressure, according to standard GB / T 11546-2008. Thermal decomposition temperature (T5%): The temperature at which the resin mass loss is 5% is tested using thermogravimetric analysis according to standard GB / T 27761-2011. Limiting Oxygen Index (LOI): Tested according to standard GB / T 2406.2-2009; Vertical flammability rating: Tested according to standard UL94-2013.

[0030]

[0031] As can be seen from the table above, the products of Examples 1-4 of this invention are superior to the comparative examples in terms of flame retardancy, high and low temperature impact resistance, and stability. The LOI of the products prepared in Examples 1-4 all exceed 32%, the vertical burning rating reaches V-0, and the tensile strength retention rate after high and low temperature cycling exceeds 90%. In contrast, the product prepared in Comparative Example 1 does not contain silicon, and the product prepared in Comparative Example 2 does not contain phosphorus. Due to the lack of phosphorus-silicon synergy, the flame retardancy and high and low temperature resistance are significantly reduced. Comparative Example 3 was prepared by physical blending. Due to the weak bonding force between the flame retardant and the matrix, serious precipitation problems occurred, resulting in extremely poor mechanical properties and flame retardant stability. This fully demonstrates the superiority of the technical solution of this invention.

[0032] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Various equivalent modifications or substitutions can be made to the embodiments of the present invention by those skilled in the art without departing from the spirit and essence of the invention, and such modifications or substitutions should all be within the scope of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should also be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin, characterized in that: The method includes the following steps: (1) Dissolve DOPO and DAPEG in solvent respectively. Under nitrogen protection and temperature of 100-130℃, add di-tert-butyl peroxide as an initiator to the DOPO solution, and then slowly add the DAPEG solution dropwise, allowing DOPO and DAPEG to react in a molar ratio of 1:1.1-1.

2. After the addition is complete, continue to react fully under nitrogen protection and temperature of 100-130℃. After the reaction is complete, remove the unreacted DAPEG first, and then remove the solvent to obtain the product DOPO-DAPEG. (2) Under nitrogen protection and at a temperature of 20-40℃, pentaerythritol triallyl ether (APE) was slowly added dropwise to the product DOPO-DAPEG. Using phosphazene base as a catalyst, the product DOPO-DAPEG and APE were reacted in a molar ratio of 1.0-1.1:

1. After the addition was completed, the reaction was continued under nitrogen protection and at a temperature of 20-40℃ until the reaction was completed. The product DOPO-DAPEG-APE was obtained. (3) The product DOPO-DAPEG-APE and γ-mercaptopropyltrimethoxysilane were mixed with the photoinitiator 2,2-dimethoxy-2-phenylacetophenone and the antioxidant in a molar ratio of 1:2 and then reacted thoroughly under ultraviolet light irradiation at 365 nm and temperature of 15-40 °C. After the reaction was completed, 2,2-dimethoxy-2-phenylacetophenone was removed to obtain the silane-terminated product. (4) Mix the silane-terminated product, the initiator benzoyl peroxide, the chain growth control agent 2,4-diphenyl-4-methyl-1-pentene, and the solvent. Under the conditions of 70-90℃ and nitrogen protection, add allyl glycidyl ether dropwise according to the molar ratio of silane-terminated product to allyl glycidyl ether of 1-1.05:

1. After the addition is completed, continue to react fully under the conditions of 70-90℃ and nitrogen protection. After the reaction is completed, remove the solvent to obtain the phosphorus-silicon synergistic grafted high and low temperature impact resistant flame retardant resin.

2. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin as described in claim 1, characterized in that: In step (1), the number average molecular weight of DAPEG is 400~1000.

3. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin as described in claim 1, characterized in that: In step (1), the amount of di-tert-butyl peroxide used is 1.5% to 3% of the total mass of DOPO and DAPEG.

4. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin as described in claim 1, characterized in that: In step (2), the phosphazene base is one or a mixture of two of t-BuP2 and t-BuP4 in any mass ratio, and the amount used is 0.8% to 1.5% of the total mass of DOPO-DAPEG and APE.

5. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact resistant flame retardant resin as described in claim 1, characterized in that: In step (3), the amount of 2,2-dimethoxy-2-phenylacetophenone used is 0.5% to 1% of the total mass of DOPO-DAPEG-APE and γ-mercaptopropyltrimethoxysilane.

6. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin as described in claim 1, characterized in that: In step (3), the intensity of ultraviolet radiation is 5~10mW / cm².

7. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin as described in claim 1, characterized in that: In step (3), the antioxidant is antioxidant 1010, and the amount used is 0.1-0.3% of the total mass of DOPO-DAPEG-APE and γ-mercaptopropyltrimethoxysilane.

8. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin as described in claim 1, characterized in that: In step (3), the photoinitiator 2,2-dimethoxy-2-phenylacetophenone is removed by silica gel column chromatography.

9. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin as described in claim 1, characterized in that: In step (1), the solvent is any one of dimethylformamide and dimethylacetamide or a mixture of two of them in any mass ratio; in step (4), the solvent is any one of toluene, xylene, and propylene glycol methyl ether or a mixture of two or more of them in any mass ratio.

10. The preparation method of the phosphorus-silicon synergistic grafted high and low temperature impact-resistant flame-retardant resin as described in claim 1, characterized in that: In step (4), the amount of benzoyl peroxide used is 0.2% to 2.0% of the total mass of the silane-terminated product and allyl glycidyl ether, and the amount of the chain growth control agent 2,4-diphenyl-4-methyl-1-pentene used is 0.2% to 1.0% of the total mass of the silane-terminated product and allyl glycidyl ether.

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