Preparation method of terminated brominated epoxy resin

Abstract

The invention discloses a preparation method of end-capped brominated epoxy resin, which comprises the following steps: carrying out polymerization reaction on tetrabromobisphenol A and tetrabromobisphenol A diglycidyl ether to obtain tetrabromobisphenol A type resin of which the terminal group is phenolic hydroxyl group, adding 2, 4, 6-tetrabromobisphenol A type resin, and reacting to obtain the end-capped brominated epoxy resin. And carrying out end capping on tetrabromobisphenol A type resin of which the terminal group is phenolic hydroxyl group by using 2, 3, 6-tribromophenol glycidyl ether to prepare the end-capped brominated epoxy resin. The preparation method of the end-capped brominated epoxy resin provided by the invention is simple in process, and the product is good in thermal stability and high in bromine content and has good industrial popularization and application values.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of a capped brominated epoxy resin. BACKGROUND

[0002] In recent years, with the rapid development of new energy vehicles, 5G communication and other industries and the continuous improvement of national fire prevention standards, the development of flame retardant industry has been greatly promoted. Among them, brominated epoxy resin (BEO) is an environmentally friendly polymer flame retardant, which has the characteristics of high decomposition temperature, good compatibility with the flame-retardant substrate, little influence on the mechanical properties and electrical properties of the substrate, etc., and is widely used in the flame retardation of ABS, HIPS, PP, PBT and other materials.

[0003] BEO can be divided into EP type and EC type according to the end group structure. Compared with EP type brominated epoxy resin, EC type has higher bromine content, better heat resistance and flow stability, and is an ideal flame retardant for HIPS, ABS and PP thin-walled products such as electronic and electrical housings. At present, the preparation of EP type BEO mainly adopts the polymerization method of tetra-bromobisphenol A bis-glycidyl ether and tetra-bromobisphenol A. On the basis of EP type, EC type BEO can be obtained by using tri-bromophenol as end-capping. However, the polymerization degree and epoxy value of EP type BEO prepared by high-temperature polymerization fluctuate greatly, which causes great difficulty in the addition amount of tri-bromophenol. If the addition amount of tri-bromophenol is insufficient, the epoxy groups on the resin will remain, the end-capping will be incomplete, and the bromine content will be low. If the addition amount of tri-bromophenol is too much, the remaining tri-bromophenol will be free in the resin material, resulting in low thermal weight loss and affecting the flame retardation. Even if the epoxy value of each batch of EP type BEO is tested and the addition amount of tri-bromophenol is accurately calculated, the epoxy groups are also easy to oxidize, ring-opening and cross-linking during the high-temperature melting stage of EP type BEO and tri-bromophenol, resulting in the remaining of tri-bromophenol. Therefore, the quality of the capped BEO product obtained by using tri-bromophenol as end-capping is unstable. SUMMARY

[0004] The present application provides a new process route for preparing a capped brominated epoxy resin to solve the problems of unstable quality, poor thermal stability and existence of 2,4,6-tri-bromophenol monomer in the polymer of the capped brominated epoxy resin prepared by the existing process route.

[0005] The preparation method of the capped brominated epoxy resin provided by the present application is as follows: first, tetra-bromobisphenol A and tetra-bromobisphenol A bis-glycidyl ether are subjected to a polymerization reaction to obtain a tetra-bromobisphenol A type resin with phenolic hydroxyl groups as end groups, and then 2,4,6-tri-bromophenol glycidyl ether is added to end-cap the tetra-bromobisphenol A type resin with phenolic hydroxyl groups as end groups to obtain the capped brominated epoxy resin.

[0006] The specific operation steps of the preparation method of the capped brominated epoxy resin of the present application are as follows: The four-bromophenol A and the four-bromophenol A diglycidyl ether are mixed under nitrogen protection, heated to a molten state at a temperature of 110-140℃, then a catalyst is added and the polymerization reaction is carried out at a temperature of 140-170℃, then the glycidyl ether of 2,4,6-tribromophenol is added and the addition reaction is carried out at a temperature of 140-170℃, and the capped brominated epoxy resin is prepared after the addition reaction is completed.

[0007] The high-temperature discharge is carried out after the addition reaction is completed, and the capped brominated epoxy resin particles are obtained after the product is cooled, solidified and crushed.

[0008] The temperature of the high-temperature discharge is 140-170℃.

[0009] The catalyst is any one of tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride and benzyltriphenylphosphonium bromide.

[0010] The amount of the catalyst is 0.1-0.6% of the mass of the four-bromophenol A diglycidyl ether.

[0011] The polymerization reaction time is 0.25-1.0 hour, and the addition reaction time is 0.5-1.5 hour.

[0012] The molar amount of the four-bromophenol A is more than that of the four-bromophenol A diglycidyl ether, i.e. the amount of the four-bromophenol A is more than that of the four-bromophenol A diglycidyl ether in terms of molar number.

[0013] The mass ratio of the four-bromophenol A to the four-bromophenol A diglycidyl ether is 1.01-1.24:1.

[0014] The addition amount W of the glycidyl ether of 2,4,6-tribromophenol satisfies the following formula: { (mass of the four-bromophenol A×bromine content of the four-bromophenol A) + (mass of the four-bromophenol A diglycidyl ether×bromine content of the four-bromophenol A diglycidyl ether) + (W×bromine content of the glycidyl ether of 2,4,6-tribromophenol)} / (mass of the four-bromophenol A+mass of the four-bromophenol A diglycidyl ether+W) = the set percentage content of bromine in the capped brominated epoxy resin.

[0015] The set percentage content of bromine in the capped brominated epoxy resin is 54-56%.

[0016] The method for preparing end-capped brominated epoxy resin provided by this invention allows for the calculation of the amount of 2,4,6-tribromophenol glycidyl ether added as the end-capping reagent, based on the set bromine content of the target product (i.e., end-capped brominated epoxy resin). This method makes it easier to control the bromine content of the target product and ensures better flame retardant performance of the material. Existing 2,4,6-tribromophenol end-capping processes require determining the amount of 2,4,6-tribromophenol added based on the epoxy value of the resin before end-capping. Since the amount of 2,4,6-tribromophenol added cannot be fixed, the bromine content of the target product fluctuates, resulting in variations in the flame retardant performance of the obtained resin.

[0017] Existing end-capped brominated epoxy resins are prepared by reacting tetrabromobisphenol A with tetrabromobisphenol A diglycidyl ether, followed by end-capping with 2,4,6-tribromophenol; the preparation route is shown in the following formula: .

[0018] This invention prepares a capped brominated epoxy resin by first polymerizing tetrabromobisphenol A with tetrabromobisphenol A bisglycidyl ether, and then adding 2,4,6-tribromophenol glycidyl ether for end-capping; the preparation route is shown in the following formula: .

[0019] The existing process for preparing end-capped brominated epoxy resin is as follows: tetrabromobisphenol A (with a molar amount less than tetrabromobisphenol A diglycidyl ether) is polymerized with tetrabromobisphenol A diglycidyl ether to obtain a tetrabromobisphenol A type resin with epoxy ends. Then, 2,4,6-tribromophenol is added to react with the epoxy groups at the ends of the resin to complete the end-capping of the resin. However, this process has many defects: (1) The number of epoxy groups in the resin obtained by polymerizing tetrabromobisphenol A with tetrabromobisphenol A diglycidyl ether fluctuates, and the number of epoxy groups needs to be determined according to the tested epoxy value. Since epoxy groups have strong reactivity, they can react with alkyl hydroxyl groups on the resin chain at high temperatures. Temperature, reaction time and other factors will have a great influence on the epoxy value of the resin, and the parallelism of the epoxy value index of the polymer product is not easy to control. (2) The amount of 2,4,6-tribromophenol added is not easy to control precisely. The amount of 2,4,6-tribromophenol added needs to be determined based on the epoxy value index. The epoxy value needs to be determined by sampling and testing. During the sampling and testing period, the epoxy groups are still undergoing chemical reactions such as cross-linking and addition, and the stability of the resin is poor. Therefore, it is difficult to accurately calculate the amount of 2,4,6-tribromophenol added. If 2,4,6-tribromophenol is added in excess, the remaining 2,4,6-tribromophenol will be free in the resin material, resulting in a lower thermal weight loss and affecting its use. If 2,4,6-tribromophenol is added inadequately, the bromine content will be low, and there may be unreacted epoxy groups. When flame retardant other polymer materials, the epoxy groups may undergo further cross-linking reactions, affecting the viscosity and flowability of the matrix resin. (3) 2,4,6-tribromophenol is easy to sublimate, and the sublimation temperature is only 90℃. Under higher end-capping temperature (at least 130℃ or above, otherwise the resin will not melt and cannot be mixed and reacted), the reaction is easily incomplete due to sublimation, which requires high end-capping equipment. Existing processes produce end-capped brominated epoxy resins with significant performance variations and unstable quality.

[0020] This invention uses tetrabromobisphenol A diglycidyl ether, tetrabromobisphenol A, and 2,4,6-tribromophenol glycidyl ether as raw materials. First, tetrabromobisphenol A, in a molar amount greater than that of tetrabromobisphenol A diglycidyl ether, is polymerized with tetrabromobisphenol A diglycidyl ether to obtain a tetrabromobisphenol A type resin with phenolic hydroxyl groups at the end. Then, 2,4,6-tribromophenol glycidyl ether is added to the tetrabromobisphenol A type resin with phenolic hydroxyl groups at the end to continue the reaction, yielding a capped brominated epoxy resin. In this process, the epoxy value of the resin does not need to be controlled in the polymerization step of tetrabromobisphenol A diglycidyl ether and tetrabromobisphenol A; only the degree of polymerization needs to be controlled. After polymerization, the resulting resin has phenolic hydroxyl groups at the end, and the resin structure does not contain any active groups, resulting in good resin stability. Based on molar quantities, the amount of tetrabromobisphenol A used in this invention is more than that of tetrabromobisphenol A diglycidyl ether, thus obtaining a tetrabromobisphenol A type resin with a phenolic hydroxyl terminal group. The mass ratio of tetrabromobisphenol A to tetrabromobisphenol A diglycidyl ether is preferably 1.01 to 1.24:1.

[0021] The end-capping reagent used in this invention is 2,4,6-tribromophenol glycidyl ether, which eliminates the problem of residual end-capping reagent. Even if there is an excess of 2,4,6-tribromophenol glycidyl ether, the excess 2,4,6-tribromophenol glycidyl ether can be completely reacted by extending the reaction time of the end-capping stage, and the alcohol hydroxyl groups in the tetrabromobisphenol A resin chain can react completely.

[0022] The end-capped brominated epoxy resin preparation process provided by this invention is easier to control than existing processes. It eliminates the need for epoxy value testing, and the amount of 2,4,6-tribromophenol glycidyl ether added can be calculated using the formula provided by this invention. In the second step, 2,4,6-tribromophenol glycidyl ether is used to cap the phenolic hydroxyl-terminated resin polymer. Compared to the traditional method of capping epoxy group-terminated resins with 2,4,6-tribromophenol, there is no residual capping reagent, and 2,4,6-tribromophenol glycidyl ether does not sublimate. The resulting product exhibits better thermal stability and lower molecular weight polydispersity, demonstrating significant technical advantages and making it suitable for industrial application. Attached Figure Description

[0023] Figure 1 Thermogravimetric analysis (TGA) spectrum of the product prepared in Example 1; Figure 2 Gel permeation chromatography (GPC) chromatogram of the product prepared in Example 1; Figure 3 Thermogravimetric analysis (TGA) spectrum of the product prepared in Comparative Example 1; Figure 4 Gel permeation chromatography (GPC) chromatogram of the product prepared for Comparative Example 1. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention. Example 1

[0025] Preparation of end-capped brominated epoxy resin with a bromine content of 55.4%: 196.8 g (0.3 mol) tetrabromobisphenol A bisglycidyl ether and 219.8 g (0.404 mol) tetrabromobisphenol A were added to a 500 mL reaction vessel. Under nitrogen protection, mechanical stirring, and heating at 120 °C, the mixture was melted and mixed evenly. Then, 0.3 g (0.00045 mol) benzyltriphenylphosphonium chloride was added, and the temperature was raised to 150 °C and reacted for 0.5 hours. After the reaction was completed, 85.1 g (0.220 mol) 2,4,6-tribromophenol glycidyl ether was added, and the mixture was reacted at 170 °C for 1.0 hour. After the reaction was completed, the mixture was discharged at 170 °C. After the liquid cooled and solidified, it was pulverized to obtain end-capped brominated epoxy resin particles. The weight-average molecular weight (Mw) of the end-capped brominated epoxy resin particles was determined to be 4905, the polydispersity was 2.15, the 1% thermal decomposition temperature was 337℃, and the bromine content was 55.5%. Example 2

[0026] Preparation of end-capped brominated epoxy resin with a bromine content of 55.3%: 196.8 g (0.3 mol) tetrabromobisphenol A bisglycidyl ether and 207.0 g (0.381 mol) tetrabromobisphenol A were added to a 500 mL reaction vessel. Under nitrogen protection, mechanical stirring, and heating at 130 °C until homogeneous melting was achieved, 0.2 g (0.00068 mol) tetrabutylphosphonium chloride was added, and the temperature was raised to 140 °C for 1 hour. After the reaction was completed, 90.1 g (0.233 mol) 2,4,6-tribromophenol glycidyl ether was added, and the reaction was carried out at 160 °C for 1.5 hours. After the reaction was completed, the material was discharged at 160 °C. After the liquid cooled and solidified, it was pulverized to obtain end-capped brominated epoxy resin particles. The weight-average molecular weight (Mw) of the end-capped brominated epoxy resin particles was determined to be 5833, the polydispersity was 2.28, the 1% thermal decomposition temperature was 335℃, and the bromine content was 55.3%. Example 3

[0027] Preparation of end-capped brominated epoxy resin with a bromine content of 56.0%: 196.8 g (0.3 mol) tetrabromobisphenol A bisglycidyl ether and 243.0 g (0.447 mol) tetrabromobisphenol A were added to a 500 mL reaction vessel. Under nitrogen protection, mechanical stirring, and heating at 140 °C, the mixture was melted and mixed evenly. Then, 0.3 g (0.00069 mol) benzyltriphenylphosphonium bromide was added, and the temperature was raised to 140 °C for 0.25 hours. After the reaction was completed, 127.4 g (0.329 mol) 2,4,6-tribromophenol glycidyl ether was added, and the mixture was reacted at 160 °C for 1 hour. After the reaction was completed, the mixture was discharged at 160 °C. After the liquid cooled and solidified, it was pulverized to obtain end-capped brominated epoxy resin particles. The weight-average molecular weight (Mw) of the end-capped brominated epoxy resin particles was determined to be 2944, the polydispersity was 2.19, the 1% thermal decomposition temperature was 330℃, and the bromine content was 56.2%. Example 4

[0028] Preparation of end-capped brominated epoxy resin with a bromine content of 55.3%: 196.8 g (0.3 mol) tetrabromobisphenol A bisglycidyl ether and 198.8 g (0.366 mol) tetrabromobisphenol A were added to a 500 mL reaction vessel. Under nitrogen protection, mechanical stirring, and heating at 110 °C, the mixture was melted and mixed evenly. Then, 1.18 g (0.003 mol) benzyltriphenylphosphonium chloride was added, and the temperature was raised to 150 °C and reacted for 0.4 hours. After the reaction was completed, 93.3 g (0.241 mol) 2,4,6-tribromophenol glycidyl ether was added, and the mixture was reacted at 150 °C for 0.5 hours. After the reaction was completed, the mixture was discharged at 150 °C. After the liquid cooled and solidified, it was pulverized to obtain end-capped brominated epoxy resin particles. The weight-average molecular weight (Mw) of the end-capped brominated epoxy resin particles was determined to be 6222, the polydispersity was 2.40, the 1% thermal decomposition temperature was 340℃, and the bromine content was 55.2%. Example 5

[0029] Preparation of end-capped brominated epoxy resin with a bromine content of 55.4%: 196.8 g (0.3 mol) of tetrabromobisphenol A bisglycidyl ether and 219.8 g (0.404 mol) of tetrabromobisphenol A were added to a 500 mL reaction vessel. Under nitrogen protection, mechanical stirring, and heating at 130 °C, the mixture was melted and thoroughly mixed. Then, 0.79 g (0.0027 mol) of tetrabutylphosphonium chloride was added, and the temperature was raised to 160 °C for 0.25 hours. After the reaction was complete, 85.1 g (0.220 mol) of 2,4,6-tribromophenol glycidyl ether was added, and the reaction was carried out at 160 °C for 1.5 hours. After the reaction was completed, the mixture was discharged at 160 °C. After cooling and solidification, the mixture was pulverized to obtain end-capped brominated epoxy resin particles. The weight-average molecular weight (Mw) of the end-capped brominated epoxy resin particles was determined to be 4915, the polydispersity was 2.33, the 1% thermal decomposition temperature was 331℃, and the bromine content was 55.6%. Example 6

[0030] Preparation of end-capped brominated epoxy resin with a bromine content of 54.0%: 196.8 g (0.3 mol) tetrabromobisphenol A bisglycidyl ether and 198.8 g (0.366 mol) tetrabromobisphenol A were added to a 500 mL reaction vessel. Under nitrogen protection, mechanical stirring, and heating at 120 °C, the mixture was melted and mixed evenly. Then, 0.2 g (0.00068 mol) tetrabutylphosphonium chloride was added, and the temperature was raised to 160 °C for 0.75 hours. After the reaction was completed, 11.5 g (0.030 mol) 2,4,6-tribromophenol glycidyl ether was added, and the mixture was reacted at 170 °C for 0.5 hours. After the reaction was completed, the mixture was discharged at 170 °C. After the liquid cooled and solidified, it was pulverized to obtain end-capped brominated epoxy resin particles. The weight-average molecular weight (Mw) of the end-capped brominated epoxy resin particles was determined to be 6211, the polydispersity was 2.66, the 1% thermal decomposition temperature was 338℃, and the bromine content was 54.2%. Example 7

[0031] Preparation of end-capped brominated epoxy resin with a bromine content of 54.4%: 196.8 g (0.3 mol) tetrabromobisphenol A bisglycidyl ether and 207.0 g (0.381 mol) tetrabromobisphenol A were added to a 500 mL reaction vessel. Under nitrogen protection, mechanical stirring, and heating at 110 °C, the mixture was melted and mixed evenly. Then, 0.3 g (0.00069 mol) benzyltriphenylphosphonium bromide was added, and the temperature was raised to 170 °C and reacted for 0.6 hours. After the reaction was completed, 27.2 g (0.007 mol) 2,4,6-tribromophenol glycidyl ether was added, and the mixture was reacted at 170 °C for 1.5 hours. After the reaction was completed, the mixture was discharged at 170 °C. After the liquid cooled and solidified, it was pulverized to obtain end-capped brominated epoxy resin particles. The weight-average molecular weight (Mw) of the end-capped brominated epoxy resin particles was determined to be 5421, the polydispersity was 2.81, the 1% thermal decomposition temperature was 338℃, and the bromine content was 54.3%. Comparative Example 1

[0032] The difference between Comparative Example 1 and Example 1 is that the molar amounts of tetrabromobisphenol A and tetrabromobisphenol A diglycidyl ether are reversed. Comparative Example 1 uses 2,4,6-tribromophenol for end-capping. Other aspects are basically the same as Example 1. The specific steps are as follows: 265.0 g (0.404 mol) of tetrabromobisphenol A diglycidyl ether and 163.2 g (0.3 mol) of tetrabromobisphenol A are added to a 500 mL reaction vessel. Under nitrogen protection, mechanical stirring, and heating at 120°C, the mixture is melted and mixed evenly. Then, 0.3 g (0.00045 mol) of benzyltriphenylphosphonium chloride is added, and the temperature is raised to 150°C for 0.5 hours. After the reaction is complete, 85.1 g (0.22 mol) of 2,4,6-tribromophenol is added, and the reaction is carried out at 170°C for 1.0 hour. After the reaction is complete, the mixture is discharged at 170°C. After the liquid cools and solidifies, it is pulverized to obtain end-capped brominated epoxy resin particles. The weight-average molecular weight (Mw) is 4871, the polydispersity is 2.57, the 1% thermal decomposition temperature is 298℃, and the bromine content is 54.3%.

[0033] The weight-average molecular weight (Mw) and polydispersity of the end-capped brominated epoxy resin particles prepared in the above embodiments were determined by gel permeation chromatography (GPC). The sample was dissolved in tetrahydrofuran eluent to prepare the test solution. The sample solution was injected into the GPC system, and the solute in the eluent was eluted from the column and continuously detected by the detector. The corresponding concentration was measured by a differential refractive index detector to obtain the corresponding spectrum. The relative molecular weight distribution and weight-average molecular weight were calculated using the calibration curve determined by the system. The 1% thermal decomposition temperature was determined by a thermogravimetric / differential thermal analyzer. The analyzer was initially heated to 500°C at a rate of 10°C / min, and the nitrogen protective gas flow rate in the sample chamber was 40 mL / min. The bromine content was determined by the oxygen flask combustion method. The sample was burned in an oxygen flask containing sodium hydroxide and hydrogen peroxide absorbent. The halogen in the sample was converted into sodium salt. Under slightly acidic conditions, the bromide ion content was titrated with silver nitrate standard titration solution, and the titration endpoint was determined by the abrupt change in electrode potential.

[0034] Figure 1 The thermogravimetric analysis (TGA) spectrum of the product prepared in Example 1 is shown below. Figure 2 The gel permeation chromatography (GPC) chromatogram of the product prepared in Example 1. Figure 3 The thermogravimetric analysis (TGA) spectrum of the product prepared in Comparative Example 1 is shown below. Figure 4 The gel permeation chromatography (GPC) chromatogram of the product prepared in Comparative Example 1 is shown. (Comparison) Figure 1 and Figure 3 The spectra show that the 1% thermogravimetric temperature of the product obtained in Example 1 is significantly higher than that of the product in Comparative Example 1, indicating that the product of Example 1 has better thermal stability. (Comparison) Figure 2 and Figure 4 As can be seen from the spectrum, the GPC spectrum of the product of Example 1 has almost no other small peaks after the main peak (smoother), while the GPC spectrum of the product of Comparative Example 1 has a large bulging peak after the main peak. This bulging peak indicates that there are more small molecules in the product. Therefore, the 1% thermal weight loss temperature of the product of Comparative Example 1 is significantly lower than that of the product of Example 1.

Claims

1. A method for preparing an end-capped brominated epoxy resin, characterized in that: This method involves first polymerizing tetrabromobisphenol A with tetrabromobisphenol A diglycidyl ether to obtain a tetrabromobisphenol A type resin with phenolic hydroxyl groups at the end, and then adding 2,4,6-tribromophenol glycidyl ether to end the tetrabromobisphenol A type resin with phenolic hydroxyl groups to obtain an end-capped brominated epoxy resin.

2. The method for preparing end-capped brominated epoxy resin according to claim 1, characterized in that: The specific steps of this method are as follows: Under nitrogen protection, tetrabromobisphenol A and tetrabromobisphenol A diglycidyl ether were mixed and heated to a molten state at 110℃~140℃. Then, a catalyst was added and the polymerization reaction was carried out at 140℃~170℃. After the polymerization reaction was completed, 2,4,6-tribromophenol glycidyl ether was added and the addition reaction was carried out at 140℃~170℃. After the addition reaction was completed, the end-capped brominated epoxy resin was obtained.

3. The method for preparing end-capped brominated epoxy resin according to claim 2, characterized in that: After the addition reaction is completed, the material is discharged at high temperature. After the product is cooled and solidified, it is pulverized to obtain end-capped brominated epoxy resin particles. The temperature of the high-temperature discharge is 140℃~170℃.

4. The method for preparing the end-capped brominated epoxy resin according to claim 2 or 3, characterized in that: The catalyst is any one of tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride, and benzyltriphenylphosphonium bromide.

5. The method for preparing the end-capped brominated epoxy resin according to claim 2 or 3, characterized in that: The amount of catalyst used is 0.1% to 0.6% of the mass of tetrabromobisphenol A diglycidyl ether.

6. The method for preparing the end-capped brominated epoxy resin according to claim 2 or 3, characterized in that: The polymerization reaction time is 0.25 to 1.0 hours; the addition reaction time is 0.5 to 1.5 hours.

7. The method for preparing the end-capped brominated epoxy resin according to any one of claims 1-3, characterized in that: The molar amount of tetrabromobisphenol A is greater than the molar amount of tetrabromobisphenol A diglycidyl ether.

8. The method for preparing end-capped brominated epoxy resin according to claim 7, characterized in that: The mass ratio of tetrabromobisphenol A to tetrabromobisphenol A diglycidyl ether is 1.01 to 1.24:

1.

9. The method for preparing the end-capped brominated epoxy resin according to any one of claims 1-3, characterized in that: The amount W added to the 2,4,6-tribromophenol glycidyl ether conforms to the following formula: {(mass of tetrabromobisphenol A × bromine content of tetrabromobisphenol A) + (mass of tetrabromobisphenol A diglycidyl ether × bromine content of tetrabromobisphenol A diglycidyl ether) + (W × bromine content of 2,4,6-tribromophenol glycidyl ether)} / (mass of tetrabromobisphenol A + mass of tetrabromobisphenol A diglycidyl ether + W) = the set percentage content of bromine in the end-capped brominated epoxy resin.

10. The method for preparing the end-capped brominated epoxy resin according to claim 9, characterized in that: The set percentage content of bromine in the end-capped brominated epoxy resin is 54% to 56%.

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