Polyhydroxy DOPO derivative, polyhydroxy DOPO derivative / organic montmorillonite composite material and preparation method of polyhydroxy DOPO derivative / organic montmorillonite composite material

Abstract

The invention belongs to the field of flame retardants, and particularly relates to a polyhydroxy DOPO derivative, a polyhydroxy DOPO derivative / organic montmorillonite composite material and a preparation method thereof. In order to further improve the flame retardance of an epoxy resin composite material and maintain better thermal performance of the composite material, DL-tyrosine, vanillin and DOPO are taken as reactants, P-H in a DOPO structure and C = N in a Schiff base intermediate generated by Schiff base reaction of the DL-tyrosine and the vanillin are subjected to addition reaction, and the hydroxyl-containing DOPO-based flame retardant is synthesized. The method is used for modifying the EP / OMMT nano composite material, and the EP / OMMT / DV-DOPO nano composite material with high flame retardance and enhanced carbon layer strength and mechanical properties is prepared.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of flame retardants, and in particular to a polyhydroxy DOPO derivative, a polyhydroxy DOPO derivative / organic montmorillonite composite material and a preparation method thereof. BACKGROUND

[0002] In recent years, the research on flame-retardant epoxy resins (EP) has attracted widespread attention [1-4] Among them, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and its derivatives are popular due to their excellent flame-retardant properties and high reactivity. The free radicals of the phosphorus-containing groups in DOPO are quenched in the gas phase after thermal decomposition, and the phosphoric acid and pyrophosphoric acid generated by decomposition catalyze the formation of a dense carbon layer, thereby playing a role in both the gas phase and the condensed phase.

[0003] At present, various DOPO-based derivatives have been used as flame retardants for EP. However, due to the limited number of active functional groups in the molecular structure of these derivatives or their low reactivity in the curing reaction with epoxy resins, the crosslinking density of the cured system is insufficient, which restricts the improvement of the comprehensive performance of epoxy resins, especially the mechanical properties. Therefore, developing new DOPO-based derivative flame retardants that can impart good flame-retardant properties to epoxy resins while maintaining or improving their mechanical properties has become a key problem that needs to be solved in this field. SUMMARY

[0004] To solve the problems in the prior art, the present application provides a polyhydroxy DOPO derivative (DV-DOPO).

[0005] The present application further provides a composite flame retardant containing the above-mentioned polyhydroxy DOPO derivative.

[0006] The present application also provides a preparation method of the above-mentioned polyhydroxy DOPO derivative and composite flame retardant.

[0007] The technical scheme adopted by the present application to achieve the above-mentioned purposes is as follows: The present application provides a polyhydroxy DOPO derivative, the structural formula of which is as follows: .

[0008] The present application also provides a preparation method of the above-mentioned polyhydroxy DOPO derivative, which comprises the following steps: (1) Dissolve vanillin and DL-tyrosine in N,N-dimethylformamide to obtain a mixture; heat and stir the mixture to obtain a Schiff base intermediate; (2) Add the Schiff base intermediate to a DOPO solution dissolved in N,N-dimethylformamide, and after reaction, filter, wash with water and dry to obtain the polyhydroxy DOPO derivative.

[0009] Preferably, in step (1), the molar ratio of vanillin and DL-tyrosine is 1:1; the reaction is heating the mixture to 85℃ and stirring for 8 h.

[0010] Preferably, in step (2), the concentration of DOPO in N,N-dimethylformamide is 1.2 mmol / mL; the molar ratio of vanillin and DOPO is 1:1; the reaction is incubating at 85℃ for 18 h.

[0011] The application also provides a composite material containing the above polyhydroxyl DOPO derivative, which is composed of flame-retardant epoxy resin EP, organic montmorillonite OMMT, polyhydroxyl DOPO derivative and curing agent PA.

[0012] The composite material provided by the application has the following mass percentage composition: flame-retardant epoxy resin EP 55.8-59.4%, organic montmorillonite OMMT 1-7%, polyhydroxyl DOPO derivative 14-20%, and curing agent PA 19.6-23.2%.

[0013] The application further provides a preparation method of the above composite material, which comprises the following steps: (a) heating the epoxy resin at a constant temperature of 95℃, then adding the epoxy resin, OMMT and polyhydroxyl DOPO derivative mixture and stirring at 95℃ for 1 h to obtain a mixture; (b) melting the curing agent PA, then mixing the curing agent with the mixture and slowly stirring until the mixture is fully mixed and solidified.

[0014] Preferably, in step (a), the constant temperature heating is heating at 95℃ for 10-15 min; and the stirring is incubating and stirring at 95℃ for 1 h.

[0015] Preferably, in step (b), the solidification is at 75℃ for more than 24 h.

[0016] The application is to further improve the flame retardancy of the epoxy resin composite material while maintaining the good thermal performance of the composite material. A hydroxyl-containing DOPO-based flame retardant is synthesized by the addition reaction of C=N in the Schiff base intermediate generated by the Schiff base reaction of P-H in the structure of DOPO with DL-tyrosine and vanillin, using DL-tyrosine, vanillin and DOPO as reactants, which is used to modify the EP / OMMT nanocomposite material, and an EP / OMMT / DV-DOPO nanocomposite material with high flame retardancy, enhanced carbon layer strength and mechanical properties is prepared.

[0017] The synthesis route of the polyhydroxyl DOPO derivative is as follows: The beneficial effects of the present application are: (1) The present application first synthesizes a hydroxyl-containing DOPO-based derivative from DL-tyrosine, vanillin and DOPO, which has good compatibility with the matrix and good flame-retardant effect and stable performance; (2) The hydroxyl-containing DOPO-based derivative synthesized from DL-tyrosine, vanillin and DOPO is used to modify EP / OMMT nanocomposites to prepare EP / OMMT / DV-DOPO nanocomposites. When 1wt% of OMMT and 20wt% of DV-DOPO are added, the composite material shows good synergistic effect in terms of heat release, smoke production, thermal stability and mechanical properties. OMMT and DV-DOPO synergistically promote the formation of a dense carbon layer, and DV-DOPO decomposes at a lower temperature to produce a gas phase product containing phosphorus, which plays a gas phase flame-retardant role. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Preparation flow chart of OMMT; Figure 2 FTIR spectra of vanillin, DL-tyrosine, DOPO and DV-DOPO; Figure 3 Video screenshots of pure EP and EP composites; Figure 4 Cone calorimeter test curves of pure EP and EP composites; wherein (a) heat release rate (kW·m⁻²), (b) total heat release (MJ·m⁻²), (c) smoke generation rate (m²·s⁻¹), (d) total smoke generation (m²); Figure 5 (a) TGA and (b) DTG of pure EP and EP composites; Figure 6 Digital images of residual carbon of composites after cone calorimeter test; wherein (a) EP, (b) EP / OMMT, (c) EP / DV-DOPO, (d) EP / OMMT-1 / DV-DOPO-20, (e) EP / OMMT-3 / DV-DOPO-18, (f) EP / OMMT-5 / DV-DOPO-16, (g) EP / OMMT-7 / DV-DOPO-14; Figure 7 FTIR spectra of pyrolysis gas phase products of EP / OMMT-1 / DV-DOPO-20 at different temperatures; Figure 8 Mechanical property test results of pure EP and EP composites. DETAILED DESCRIPTION

[0019] The technical solutions of the present application will be further explained and described below with specific examples.

[0020] The preparation process of the organic montmorillonite OMMT used in the present application is shown in Figure 1 The specific preparation method is as follows: 10 g of MMT is added to a 500 mL three-necked flask, 200 mL of deionized water is added, water bath heating is performed, and a stirrer is used for slow stirring. 2 g of cetyltrimethylammonium bromide (CTAB) is added to a beaker, dissolved in 50 mL of deionized water, and placed in a water bath for heating. When the temperature in the three-necked flask is increased to 60°C, the quaternary ammonium salt solution is added, and heating and stirring are continued. When the temperature is increased to 80°C, it is kept constant for 3 h. After the solution is left to stand and stratify, the clear liquid is removed, and a white flocculent precipitate is obtained. Then, deionized water is added, and multiple washing and suction filtration are performed until no white or light yellow precipitate appears in the upper solution when 1% AgNO3 is added. The white flocculent material produced is placed in an oven at 80°C for 48 h, crushed into powder, and sieved to obtain OMMT. The prepared OMMT is placed in a dry and sealed plastic bottle for preparation of the composite material.

[0021] Example 1 (I) Experimental materials The experimental reagents used are shown in Table 1.

[0022] Table 1 Experimental materials (1) Synthesis of DV-DOPO Vanillin (10.87 g, 0.06 mol) and DL-tyrosine (9.13 g, 0.06 mol) are dissolved in 90 mL of N, N-dimethylformamide, and the mixture is placed in a 250 mL three-necked flask equipped with a reflux condenser and a mechanical stirrer. The mixture is heated to 85°C, and stirred at this temperature for 8 h to obtain a Schiff base intermediate. Then, a solution of DOPO (12.97 g, 0.06 mol) dissolved in 50 mL of N, N-dimethylformamide is added, and the reaction is carried out at 85°C for 18 h. After the reaction is completed, the precipitate is filtered, and the crude product is washed with water. After drying in a vacuum drying oven at 75°C for 48 h, grinding is performed to obtain a light yellow powder.

[0023] (2) Characterization of DV-DOPO The FTIR test spectra of vanillin, DL-tyrosine, DOPO, and DV-DOPO are shown in Figure 2 From the figure, it can be seen that in the infrared spectrum of DV-DOPO, the vibration absorption peak of P-H bond in phosphoryl group is at 2437 cm -1 , the stretching vibration absorption peaks of N-H in amino group are at 3207 cm -1 and 3110 cm -1 , and the absorption peak of C=O is at 1667 cm-1 characteristic peak of C=0 in aldehyde group disappeared. In addition, the infrared spectrum of DV-DOPO also had C=0 stretching vibration at 2929 cm -1 , which was caused by the stretching vibration between the hydroxyl group and the carbon atom on the side chain of tyrosine. The additional absorption peak of P-O-Ph in phosphaphenanthrene was shown at 757 cm -1 , 1032 cm -1 and 1275 cm -1 , which was derived from the molecular structure of DV-DOPO.

[0024] Example 2 Preparation of composite material Firstly, the EP / DV-DOPO composite material formula was screened by single factor experiment method, and the results showed that when DV-DOPO was added by 21wt%, the composite material reached the best balance in mechanical properties, flame retardant properties and combustion performance. On this basis, the synergistic ratio optimization design was carried out: keeping the total addition amount of flame retardant system 21wt% unchanged, the gradient compounding design of OMMT and DV-DOPO was carried out. By setting the compounding gradient of OMMT / DV-DOPO, such as OMMT-1 / DV-DOPO-20, OMMT-3 / DV-DOPO-18 and other groups of ratio, the sample formula was determined. According to the formula, the corresponding mass percentage of EP, OMMT, DV-DOPO and curing agent PA was weighed, and the sample formula was shown in Table 2. The epoxy resin was placed in a constant temperature water bath, and the viscosity was reduced at 95℃. After about 10 min, the resin fluidity became good, then the EP and OMMT, DV-DOPO mixture was added into a three-necked flask and placed in a water bath for stirring at 95℃ for 1h. The curing agent PA was weighed according to the amount of resin, and was placed in an oven to be heated to 70℃ for melting. When the stirring of EP and OMMT, DV-DOPO mixture was finished, the curing agent was mixed with the mixture, slowly stirred with a glass rod, mixed fully, and then poured into a mold, and then placed in an oven to keep at 75℃ for 24h or more.

[0025] Table 2 EP / OMMT / DV-DOPO sample formula (I) Analysis of flame retardant properties of composite material The flame retardant properties of EP composite material were evaluated by UL-94 and LOI test. As Figure 3and Table 3. From the video screenshots of pure EP and EP composites during UL-94 vertical burning test, it can be seen that after the ignition of pure EP, the fire spreads rapidly from the bottom to the top, and cannot self-extinguish. Similarly, the composite added with OMMT also continues to burn and cannot self-extinguish, indicating that OMMT does not have sufficient flame retardant performance to prevent the spread and sustained combustion of the flame. The EP / DV-DOPO-21 composite has good flame retardant performance, no dripping, and can self-extinguish. White smoke is released during the combustion process, which is related to the phosphorus-containing free radicals generated by the decomposition of DV-DOPO, promoting the rapid extinguishing of the flame. After the second ignition, it is immediately extinguished, showing a carbon layer barrier effect, and the UL-94 level reaches V-2 level. Compared with the composites added with OMMT or DV-DOPO alone, the EP / OMMT / DV-DOPO nanocomposite has better flame retardant performance, among which the flame retardant performance of EP / OMMT-1 / DV-DOPO-20 is the best, and the UL-94 level reaches V-1 level, which is attributed to the more stable carbon layer formed by the initiation of OMMT and DV-DOPO. The LOI of pure EP is 21.0%, while the LOI of EP / OMMT-1 / DV-DOPO-20 composite can be increased to 25.5% with the increase of the addition amount of DV-DOPO, which is higher than that of EP / OMMT-1 and EP / DV-DOPO-21, indicating that there is a synergistic effect between DOPO derivatives and OMMT on the improvement of LOI.

[0026] Table 3 LOI and UL-94 test results of pure EP and EP composites The average time of flame burning after the first and second ignition.

[0027] The sample strip was ignited and burned to the clamping end.

[0028] (II) Analysis of the combustion behavior of the composite The combustion behavior of the epoxy resin composite was tested and studied using a cone calorimeter, Figure 4 Typical data of the cone test results of pure EP and EP composites. The PHRR of pure EP is 924.2 kW·m -2 Compared with pure EP, the PHRR of EP / OMMT-1 and EP / DV-DOPO-21 is reduced by 11.7% and 35.6%, respectively. When 1wt% of OMMT and 20wt% of DV-DOPO are added to EP, the PHRR of the composite is 424.9 kW·m -2The flame retardant effect is the best, which is reduced by 54.0% compared with pure EP. This shows that OMMT and DV-DOPO have inhibitory effect on heat release of epoxy resin during combustion, and the synergistic flame retardant effect is better. From Table 4, it can be observed that the TTI value of EP / OMMT / DV-DOPO nanocomposite increases from 42 s to 56 s with the increase of OMMT content and the decrease of DV-DOPO content, which is shorter than that of pure EP. On the one hand, OMMT inhibits the early pyrolysis gas of EP composite, delays the combustion, on the other hand, DV-DOPO can decompose at lower temperature to generate free radicals, induce matrix pyrolysis and release of volatile matter. Therefore, the TTI of EP / OMMT-1 / DV-DOPO-20 flame retardant epoxy resin composite is reduced. At the same time, EP / OMMT-1 / DV-DOPO-20 has the smallest FGI and the largest FPI, which shows that it has the smallest fire risk.

[0029] Figure 4 The smoke release rate and total smoke release amount of pure EP, EP / OMMT-1, EP / DV-DOPO-21 and EP / OMMT / DV-DOPO nanocomposites are also shown. As can be seen from the figure, pure EP has higher heat release and large amount of smoke release. With the addition of OMMT and DV-DOPO, the SPR and TSR of epoxy resin composite are reduced, which shows that OMMT and DV-DOPO can effectively inhibit the generation of smoke during combustion. Compared with pure EP, the PSPR of EP / OMMT-1 / DV-DOPO-20 composite is reduced by 33.3%, and the TSP is reduced by 28.8%. The carbon layer formed by the synergistic effect of OMMT and DV-DOPO plays a role in blocking and shielding the internal matrix material, thereby inhibiting the diffusion of smoke.

[0030] Table 4 Typical data of cone calorimeter test results of pure EP and EP composite (Three) Thermal stability analysis of composite The thermal stability of EP and EP composite in nitrogen was studied by TGA. The TGA and DTG curves are shown in Figure 5 Table 5 summarizes the related data, including the initial decomposition temperature T 5% , the maximum weight loss rate temperature T max , the maximum weight loss rate and the carbon residue at 700℃.

[0031] The thermal decomposition of pure EP shows one-step decomposition, mainly occurring between 300-500℃, T 5% and T max314.3 °C and 430.6 °C, respectively, and almost complete pyrolysis occurred, with negligible char residue at 700 °C. The thermal decomposition of the composite with 1 wt% OMMT also showed one-step decomposition, with T 5% and T max decreased to 285.4 °C and 425.5 °C, respectively, due to the loss of water of crystallization and the decomposition of the intercalating agent CTAB. The addition of OMMT promoted the formation of carbon layers, resulting in an increase in the amount of char residue. The composite with 21 wt% DV-DOPO decomposed in the temperature range of 280-400 °C, and T 5% and T max decreased more significantly to 290.8 °C and 390.8 °C, respectively, due to the lower bond energy of O=P-O on DV-DOPO than C-C, and the degradation of these phosphorus-containing groups at a relatively low temperature.

[0032] The TGA and DTG curves of the EP / OMMT / DV-DOPO nanocomposites were similar to those of EP / OMMT-1, but changed significantly compared to EP / DV-DOPO-21. With an increase in the content of DV-DOPO, the T 5% decreased, T max decreased, and the char residue increased in the EP / OMMT / DV-DOPO nanocomposites, while the total amount of flame retardant added remained unchanged. A reasonable explanation is that the intercalating agent and the phosphorus-containing groups decompose at a lower temperature, and the phosphorus-containing groups promote the dehydration of the EP matrix to form stable carbon layer structures, while DV-DOPO is a polyhydroxyl phosphate that acts as a phosphorus-containing carbon source in the composite, and synergistically promotes the formation of carbon layers in the condensed phase under the catalytic action of OMMT to form carbon. These carbon layer structures accumulate on the surface of the material, which can act as a protective barrier to inhibit the migration of flame and heat energy to the EP matrix, delay the emission of volatile degradation products, and thus effectively improve the thermal stability of the EP / OMMT / DV-DOPO nanocomposites.

[0033] Table 5 Thermal gravimetric analysis and differential thermal gravimetric data of pure EP and EP composites (Four) The apparent morphology of the char residue of the composites To further understand the synergistic effect of OMMT and DV-DOPO on carbon formation, the macroscopic structure of the char residue of the composites after the cone calorimeter test was observed. The digital images of the char residue of the samples are shown in Figure 6The tin foil was burned through, exposing the glass wool inside the sample box. The composite with 1 wt% OMMT alone had no complete carbon residue layer, and the scattered carbon layer surface was continuous and dense, with a smooth surface, but the amount of carbon residue was small, and the carbon layer was very thin. The composite with 21 wt% DV-DOPO alone formed a complete carbon residue layer, which acted as a barrier to the internal matrix, which may be due to the generation of phosphorus-containing acid during the decomposition of DV-DOPO, which promotes the dehydration of EP matrix to form carbon, thereby generating a dense carbon layer rich in phosphorus elements. However, the surface of the carbon layer is uneven due to internal pores, and there are pores on the surface, making the carbon layer prone to brittle fracture. The EP / OMMT / DV-DOPO nanocomposite has a significant decrease in the number of pores and cracks on the surface of the carbon layer as the DV-DOPO content increases, and the density increases, with a smoother and more compact surface, as shown in Figure 6 (d-e), which acts as a barrier to the internal matrix, and the dense and continuous carbon layer can effectively isolate the volatile gases, oxygen and heat during the combustion process. At the same time, the carbon layer has a certain physical strength and is not prone to brittle fracture. This change in macroscopic morphology further confirms the synergistic effect of OMMT and DV-DOPO in improving the carbonization ability of EP composites. However, when the OMMT content is ≥5 wt%, as shown in Figure 6 (f-g), the carbon layer integrity decreases, with more cracks and irregular fragments in the middle of the carbon layer. This change in macroscopic morphology indicates that when the OMMT content is <5 wt%, it can synergistically promote the formation of a dense and smooth carbon layer with DV-DOPO.

[0034] (V) Analysis of gas products of the composite TGA-FTIR was used to characterize the combustion products and further analyze the gas products generated during the combustion of the composite. Figure 7 The FTIR spectra of EP / OMMT-1 / DV-DOPO-20 pyrolysis products at 8 different temperatures are shown. It can be seen that the main pyrolysis products of EP / OMMT-1 / DV-DOPO-20 are water or hydroxyl at 3650 cm -1 , hydrocarbons at 2950 cm -1 , carbon dioxide at 2350 cm -1 , carbonyl compounds at 1730 cm -1 , and aromatic compounds at 1508 cm -1 . In addition, at 380°C, the infrared absorption peaks are at 1254 cm -1 and 1170 cm -1The stretching vibration belonging to P=O and P-O-C indicates that DV-DOPO in the composite can decompose at a lower temperature to produce phosphorus-containing gas phase products, which can not only dilute the combustible gas on the surface of the composite, but also react with the ·OH free radicals generated when the composite is heated to form a chain reaction, thereby playing a quenching role and a gas phase flame-retardant role.

[0035] (VI) Mechanical properties of the composite The mechanical properties are an important factor for evaluating the applicability of the epoxy resin material, and affect the application field of the epoxy resin material. The electronic universal tensile testing machine was used to test and characterize the mechanical properties of pure EP and EP composite, Figure 8 The mechanical properties of pure EP and EP composite were tested. As can be seen from the figure, pure EP showed high tensile strength and bending strength, which were 65.65±1.72 MPa and 61.34±2.20 MPa, respectively. The tensile strength and bending strength of the composite added with 1wt% OMMT alone were significantly improved, which were 77.76±1.97 MPa and 76.25±0.66 MPa, respectively, increased by 18.44% and 24.31%. The layered structure of montmorillonite in the epoxy resin makes it have nanoscale dispersibility. When subjected to external force, the nanostructure acts as a stress concentration point, and the montmorillonite sheet layer not only initiates small cracks, but also terminates large cracks, thereby improving the mechanical properties of the material. The mechanical properties of the sample were improved by adding 21wt% DV-DOPO alone, and the tensile strength and bending strength were increased to 72.36±0.76 MPa and 66.22±2.08 MPa, respectively. A reasonable explanation is that DV-DOPO contains multiple hydroxyl groups, which can form chemical bonds or physical crosslinking with the epoxy resin, thereby improving the mechanical properties of the composite. It is worth noting that when OMMT and DV-DOPO are used to prepare flame-retardant EP, the addition of a small amount of OMMT increases the tensile strength and bending strength of the EP / OMMT / DV-DOPO blend, indicating that the appropriate amount of OMMT has a strengthening effect on the matrix due to its nanostructure and greater stiffness. Under the condition that the total amount of flame retardant is constant, the mechanical properties of the EP / OMMT / DV-DOPO nanocomposite show a trend of decreasing strength and toughness with the increase of the amount of OMMT. On the one hand, when the content of montmorillonite is too high, the already exfoliated montmorillonite sheet layer is easy to re-aggregate, resulting in a decrease in its mechanical properties. On the other hand, the decrease in the content of DV-DOPO reduces the content of hydroxyl groups involved in crosslinking reactions, resulting in a decrease in the mechanical properties of the composite.

Claims

1. A polyhydroxy DOPO derivative, characterized by, The structural formula is: 。 2. A method of preparing a polyhydroxy DOPO derivative as claimed in claim 1, characterized by, The method comprises the following steps: (1) Vanillin and DL-tyrosine are dissolved in N, N-dimethylformamide to obtain a mixture; the mixture is heated and stirred to react to obtain a Schiff base intermediate; (2) The Schiff base intermediate is added into a DOPO solution dissolved in N, N-dimethylformamide, and after reaction, filtration, water washing and drying, a polyhydroxy DOPO derivative is obtained.

3. The production method according to claim 2, characterized by, In step (1), the molar ratio of vanillin to DL-tyrosine is 1:1; the reaction is that the mixture is heated to 85 DEG C and stirred for 8 h.

4. The production method according to claim 2 or 3, characterized by, In step (2), the concentration of DOPO in N, N-dimethylformamide is 1.2 mmol / mL; the molar ratio of vanillin to DOPO is 1:1 in terms of vanillin; and the reaction is that the reaction is carried out at 85 DEG C for 18 h.

5. A composite material comprising the polyhydroxylated DOPO derivative of claim 1 or prepared by the method of any one of claims 3-4, characterized in that, The composite material is composed of flame-retardant epoxy resin EP, organic montmorillonite OMMT, polyhydroxy DOPO derivative and curing agent PA.

6. The composite material of claim 5, wherein, The composite material comprises, by mass percentage, 55.8-59.4% of flame-retardant epoxy resin EP, 1-7% of organic montmorillonite OMMT, 14-20% of polyhydroxy DOPO derivative and 19.6-23.2% of curing agent PA.

7. A method of producing a composite material as claimed in claim 5 or 6, characterised in that, The method comprises the following steps: (a) The epoxy resin is heated at a constant temperature of 95 DEG C, and then the mixture of the epoxy resin, OMMT and polyhydroxy DOPO derivative is added and stirred at 95 DEG C for 1 h to obtain a mixture; (b) The curing agent PA is melted, and then the curing agent is mixed with the mixture and slowly stirred until the mixture is fully mixed and then cured.

8. The preparation method according to claim 7, characterized in that, In step (a), the constant temperature heating is heating at 95 DEG C for 10-15 min; and the stirring is stirring at 95 DEG C for 1 h.

9. The production method according to claim 7 or 8, characterized by, In step (b), the curing is curing at 75 DEG C for more than 24 h.

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