Organophosphorus nitrogen metal complex compound flame retardant, and boron nitride hybrid / epoxy resin composite material and preparation method thereof

Abstract

The present application relates to a kind of organic phosphorus nitrogen metal complex compound flame retardant, and its boron nitride hybrid / epoxy resin composite material and preparation method, wherein with organic phosphine compound, i.e. 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as raw material, with the imidazole of unsaturated bond is added to obtain organic phosphorus nitrogen compound, different nitrate is reacted with the synthesized organic phosphorus nitrogen compound, and different organic phosphorus nitrogen metal complex compound flame retardant is synthesized.Compared with prior art, the preparation process of the organic phosphorus nitrogen metal complex compound boron nitride hybrid involved in the present application is simple, easy to mass production;The organic phosphorus nitrogen metal complex compound boron nitride hybrid / epoxy resin composite material prepared in the present application not only has excellent flame retardant performance, but also has outstanding heat conduction performance, can be applied in new energy battery packaging material, electronic component packaging material and other thermal management field.

Description

Technical Field

[0001] This invention relates to the field of functional materials preparation technology, and in particular to an organophosphorus-nitrogen metal coordination compound, an organophosphorus-nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material, and a preparation method thereof. Background Technology

[0002] Epoxy resins possess advantages such as high bonding strength, low shrinkage, excellent electrical insulation, thermal stability, good processability, and mechanical properties, making them widely used in coatings, adhesives, composite materials, and electronics. For example, in the field of electronic packaging materials, epoxy resins are commonly used to manufacture adhesives and encapsulation materials for integrated circuits and electronic devices. With the miniaturization and high integration of the electronics industry, the number of electronic components per unit area is increasing, leading to a sharp rise in heat density per unit area. This places higher demands on the thermal conductivity of materials used in electronic components. If heat dissipation is not timely during operation, the accumulation of large amounts of heat can affect equipment operation and even cause fires. Therefore, more stringent requirements are placed on the thermal conductivity and flame retardancy of the materials used. However, the oxygen index of epoxy resins is generally around 19.8%, classifying them as flammable materials; moreover, epoxy resins have poor thermal conductivity, with a thermal conductivity coefficient generally around 0.2 W / (m·K), which is insufficient to meet the thermal conductivity requirements of materials used in the electronics field. Therefore, research on the flame retardancy and thermal conductivity of epoxy resins has attracted increasing attention.

[0003] Boron nitride (BN) is a thermally conductive filler with high thermal conductivity, good chemical stability, and excellent insulation properties, and is widely used in thermal management. While adding BN as a filler to polymers can effectively improve their thermal conductivity, BN's flame retardant efficiency is low. Therefore, flame-retardant functionalization modification of BN is necessary to enhance its flame-retardant properties.

[0004] Patent CN114836007A discloses a high thermal conductivity insulating epoxy resin material and its preparation method. Specifically, the preparation process involves immersing a boron nitride nanomaterial—a POSS framework—into an epoxy resin matrix, subjecting it to vacuum treatment to obtain a boron nitride nanosheet-POSS framework epoxy resin matrix material prepreg. After curing at a higher temperature, a boron nitride / epoxy resin-based insulating material with a three-dimensional thermally conductive framework is obtained. The boron nitride forms a continuous framework structure within the epoxy resin, creating dense thermally conductive pathways and improving the insulation and thermal conductivity of the epoxy resin. Patent CN114806090A discloses a high thermal conductivity and insulating epoxy resin composite material using modified boron nitride and modified carbon fiber as inorganic fillers, and its preparation method. The main components are: 100 parts epoxy resin, 20-30 parts curing agent, and 5-35 parts inorganic filler. The specific steps involve modifying boron nitride with a silane coupling agent, modifying carbon fiber with dopamine hydrochloride solution, mixing the modified boron nitride and modified carbon fiber evenly, adding the epoxy resin, stirring and dispersing, and then heating and curing in stages to obtain the epoxy resin composite material, thus improving the thermal conductivity of the epoxy resin. However, these inventions only use boron nitride as a thermally conductive filler; the flame retardant properties of the prepared epoxy resin composite material are not significantly improved.

[0005] Patent CN114989395A discloses a DOPO derivative flame retardant / epoxy resin composite, which comprises the following components: 40 parts epoxy resin, 10-15 parts DOPO derivative, 30 parts curing agent, and 20-60 parts flame retardant synergist. By adding DOPO to p-hydroxybenzophenone, a DOPO derivative with hydroxyl groups is obtained. This derivative is then compounded with the flame retardant synergist and applied to epoxy resin to prepare a flame-retardant functionalized epoxy resin composite with good flame retardant properties. However, this patent only considers the flame-retardant effect of the DOPO derivative on the epoxy resin and does not improve its thermal conductivity. Summary of the Invention

[0006] To address the shortcomings of poor flame retardancy and thermal conductivity of epoxy resin, this invention proposes an organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material and its preparation method. The prepared epoxy resin composite material exhibits excellent flame retardancy and good thermal conductivity.

[0007] First, the inventor believed during the conceptualization process that:

[0008] Organophosphorus and nitrogen metal coordination compounds are halogen-free, safe, and environmentally friendly. Their synthesis process is simple, and they are not easily hydrolyzed. In recent years, they have been found to exhibit excellent flame-retardant properties in polymers (including epoxy resins). Therefore, this invention loads organophosphorus and nitrogen metal coordination compounds onto boron nitride microsheets to prepare a hybrid of organophosphorus and nitrogen metal coordination compounds and boron nitride microsheets. This hybrid improves the flame-retardant properties of the boron nitride microsheets while also leveraging their excellent thermal conductivity.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] The first aspect of this invention provides an organophosphorus-nitrogen metal coordination compound flame retardant, wherein the organophosphorus-nitrogen compound ligand has the following general structural formula:

[0011]

[0012] In the formula, R represents H or CH3.

[0013] A second aspect of the present invention provides a method for preparing the organophosphorus nitrogen metal coordination compound flame retardant as described above, comprising the following steps:

[0014] S1: DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) was reacted with an equimolar amount of 1-vinylimidazolium compound under reflux at 140-180 °C for 4-12 hours to obtain organophosphorus nitrogen compound ligands;

[0015] S2: After cooling, the organophosphorus nitrogen compound ligand is first dissolved in anhydrous ethanol to obtain an ethanol solution of the organophosphorus nitrogen compound ligand. Then, the ethanol solution of nitrate is slowly added and reacted at room temperature for 1 to 4 hours to obtain the organophosphorus nitrogen metal coordination compound.

[0016] Further, in S2, the nitrate is selected from one or more of zinc nitrate, aluminum nitrate, copper nitrate, ferric nitrate, or chromium nitrate.

[0017] Furthermore, in S2, the molar ratio of the organophosphorus nitrogen compound ligand to the nitrate is 1:1 to 10:1, the reaction temperature is 25 to 95 °C, the reaction time is 1 to 24 h, and the pH is 1 to 10.

[0018] The third aspect of the present invention provides an organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material, comprising the following raw materials in parts by weight: 5-15 parts of organophosphorus nitrogen metal coordination compound@boron nitride micro flakes, 15-20 parts of curing agent, and bisphenol A type epoxy resin to make up to 100 parts.

[0019] The organophosphorus nitrogen metal coordination compound@boron nitride hybrid was prepared by the following method: an ethanol solution of boron nitride microflakes, an ethanol solution of the organophosphorus nitrogen metal coordination compound flame retardant, and an ethanol solution of nitrate were added to a reactor, and after uniform stirring and reaction, the product was centrifuged, washed with alcohol, and dried to obtain the organophosphorus nitrogen metal coordination compound@boron nitride hybrid.

[0020] More preferably, the amount of organophosphorus nitrogen metal coordination compound@boron nitride hybrid is 15 parts.

[0021] Furthermore, the organophosphorus-nitrogen metal coordination compound flame retardant is selected from one or more organophosphorus-nitrogen zinc coordination compounds, organophosphorus-nitrogen aluminum coordination compounds, organophosphorus-nitrogen copper coordination compounds, organophosphorus-nitrogen iron coordination compounds, and organophosphorus-nitrogen chromium coordination compounds.

[0022] More preferably, the organophosphorus-nitrogen metal coordination compound flame retardant is an organophosphorus-nitrogen-iron coordination compound.

[0023] Furthermore, the mass ratio of the organophosphorus nitrogen metal coordination compound to the boron nitride microsheets is 1:5 to 3:1.

[0024] More preferably, the mass ratio of the organophosphorus nitrogen metal coordination compound to the boron nitride microflakes is 1:1 to 1:6, and more preferably 1:1 to 1:3.

[0025] Furthermore, the curing agent is selected from one or more of heterocyclic amine curing agents, aromatic amine curing agents, acid anhydride curing agents, or alicyclic amine curing agents.

[0026] A fourth aspect of the present invention provides a method for preparing an organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material as described above, comprising the following steps:

[0027] Weigh out the bisphenol A type epoxy resin, organophosphorus nitrogen metal coordination compound@boron nitride hybrid and curing agent according to the formula, stir evenly at 100 ℃ and put into polytetrafluoroethylene mold, and cure in different temperature ranges and time periods. The curing temperature is 100 ℃~150 ℃ and the curing time is 2~5 h.

[0028] Compared with existing technologies, it has the following beneficial effects:

[0029] 1) This invention incorporates an organophosphorus nitrogen metal coordination compound@boron nitride hybrid into epoxy resin. By controlling the feeding ratio of the two, the mass ratio of the organophosphorus nitrogen metal coordination compound to boron nitride microflakes in the modified boron nitride can be directly controlled. Furthermore, the organophosphorus nitrogen metal coordination compound@boron nitride hybrid is added to the epoxy resin matrix to obtain an epoxy resin composite material that combines high thermal conductivity and excellent flame retardant properties. The organophosphorus nitrogen metal coordination compound is a flame retardant additive prepared by coordinating organophosphorus nitrogen compounds with metal ions. The organophosphorus nitrogen compounds are synthesized through the addition reaction of DOPO with 1-vinylimidazolium compounds. When heated, organophosphorus nitrogen flame retardants can promote the carbonization of the epoxy resin matrix to form an expanded char layer. The presence of metal ions can improve the quality of the char layer. Boron nitride microflakes, as high-temperature resistant and highly thermally conductive fillers, also have a certain physical barrier effect during epoxy resin combustion. Therefore, the organophosphorus nitrogen metal coordination compound@boron nitride hybrid exhibits excellent flame retardant properties in epoxy resin.

[0030] 2) Although boron nitride microsheets have a high thermal conductivity, their excellent thermal conductivity is difficult to fully realize due to poor compatibility with epoxy resin and a high interfacial thermal resistance at the interface. Loading organophosphorus nitrogen metal coordination compounds onto boron nitride microsheets can improve the compatibility between the microsheets and epoxy resin, reduce the interfacial thermal resistance, and thus effectively improve the thermal conductivity of epoxy resin composites. Detailed Implementation

[0031] Overall, this invention relates to the synthesis of organophosphorus-nitrogen metal coordination compound flame retardants, organophosphorus-nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite materials, and their preparation methods. Specifically, it includes the following steps: using an organophosphorus compound, namely 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), as a raw material, it undergoes addition reaction with an imidazole containing an unsaturated bond to obtain an organophosphorus-nitrogen compound; different nitrates are used to react with the synthesized organophosphorus-nitrogen compounds to synthesize different organophosphorus-nitrogen metal coordination compound flame retardants; during the reaction of the nitrates with the organophosphorus-nitrogen compounds, boron nitride microsheets are added to prepare different organophosphorus-nitrogen metal coordination compound@boron nitride hybrids; and then these are compounded with epoxy resin to prepare organophosphorus-nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite materials. The preparation process of the organophosphorus-nitrogen metal coordination compound@boron nitride hybrids involved in this invention is simple and easy to mass-produce. The organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material prepared by this invention not only has excellent flame retardant properties, but also outstanding thermal conductivity, and can be applied in thermal management fields such as new energy battery packaging materials and electronic component packaging materials.

[0032] The organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material of the present invention comprises the following raw materials in parts by weight: 5-15 parts of organophosphorus nitrogen metal coordination compound@boron nitride hybrid, 20-24 parts of curing agent, and bisphenol A type epoxy resin to make up to 100 parts; preferably, the organophosphorus nitrogen metal coordination compound@boron nitride hybrid is 15 parts.

[0033] Furthermore, the organophosphorus-nitrogen metal coordination compound is selected from one or more of organophosphorus-nitrogen zinc coordination compounds, organophosphorus-nitrogen aluminum coordination compounds, organophosphorus-nitrogen copper coordination compounds, organophosphorus-nitrogen iron coordination compounds, and organophosphorus-nitrogen chromium coordination compounds.

[0034] Furthermore, the mass ratio of the organophosphorus nitrogen metal coordination compound to the boron nitride microflakes is 1:5 to 5:1.

[0035] Furthermore, the selected curing agent is selected from one or more of heterocyclic amine curing agents, aromatic amine curing agents, acid anhydride curing agents, or alicyclic amine curing agents.

[0036] Furthermore, the organophosphorus nitrogen metal coordination compound@boron nitride hybrid is prepared by the following method: an ethanol solution of boron nitride microflakes, an ethanol solution of the organophosphorus nitrogen compound, and an ethanol solution of nitrate are added to a reactor, and after uniform stirring and reaction, the product is centrifuged, washed with alcohol, and dried to obtain the organophosphorus nitrogen metal coordination compound@boron nitride hybrid.

[0037] Further, the organophosphorus nitrogen compound is characterized by the following method: DOPO is refluxed with an equimolar amount of a 1-vinylimidazolium compound at 140-180°C for 4-12 hours to obtain the organophosphorus nitrogen compound; after cooling, the product is dissolved in anhydrous ethanol to obtain an ethanol solution of the organophosphorus nitrogen compound.

[0038] Furthermore, the nitrate is selected from one or more of zinc nitrate, aluminum nitrate, copper nitrate, ferric nitrate, or chromium nitrate.

[0039] Furthermore, the molar ratio of the organophosphorus nitrogen compound to the nitrate is 1:1 to 10:1, the reaction temperature is 25 to 95°C, the reaction time is 1 to 24 hours, and the pH is 1 to 10.

[0040] A method for preparing an organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material: bisphenol A type epoxy resin, organophosphorus nitrogen metal coordination compound@boron nitride hybrid and curing agent are weighed according to the specified ratio, stirred evenly at 100℃, placed into a polytetrafluoroethylene mold, and cured in stages by heating at a curing temperature of 100℃~150℃ for 2~5 h.

[0041] The present invention will now be described in detail with reference to specific embodiments, but this is by no means a limitation thereof. Any preparation methods, materials, structures, or compositional ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0042] Example 1

[0043] 43.2 g of DOPO (0.2 mol) was heated to 140 °C, 18.8 g of 1-vinylimidazole (0.2 mol) was added, and the temperature was raised to 160 °C. The mixture was stirred and refluxed for 12 h. Then, the temperature was lowered to 70 °C, 200 mL of anhydrous ethanol was added, and the mixture was stirred until no layering occurred, yielding an ethanol solution of organophosphorus nitrogen compounds (DMZ / ethanol solution). 12.1 g of copper nitrate trihydrate was dissolved in 100 mL of anhydrous ethanol, and 70 g of boron nitride microflakes (average size 5 μm) were dispersed in 200 mL of anhydrous ethanol. The above solution was then mixed with the ethanol solution of organophosphorus nitrogen compounds, and the ethanol solution of copper nitrate was added dropwise while stirring. After the addition was complete, stirring was continued for 1 h. The mixture was centrifuged, washed with ethanol, and dried under vacuum at 80 °C for 6 h to obtain organophosphorus nitrogen copper compound@boron nitride hybrid CuDMZ@BN (where the mass ratio of organophosphorus nitrogen copper compound to boron nitride microflakes was 1:1).

[0044] It should be noted that, in addition to 1-vinylimidazole, 2-methyl-1-vinylimidazole was also used in this scheme, both of which achieved flame retardant performance of UL-94 V-0 rating and improved thermal conductivity similar to those in this embodiment. Therefore, 1-vinylimidazole (0.2 mol) is used in this scheme for description.

[0045] 76.0 g of epoxy resin and 5.0 g of organophosphorus-nitrogen-copper compound@boron nitride hybrid were weighed and added to a stainless steel cup. The mixture was heated to 100 °C with continuous stirring until homogeneous. Then, 19.0 g of 4,4′-diaminodiphenylmethane curing agent was added and stirring continued for 3 min. The mixture was then vacuumed at 100 °C for 5 min. Finally, a polytetrafluoroethylene mold was added, and the mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h. The resulting epoxy resin composite material (organophosphorus-nitrogen-copper compound@boron nitride hybrid) was obtained (the amount of organophosphorus-nitrogen-copper compound@boron nitride hybrid added was 5 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0046] Example 2

[0047] 72.0 g of epoxy resin, 10.0 g of the organophosphorus-nitrogen-copper compound@boron nitride hybrid prepared according to Example 1, and 18.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare the organophosphorus-nitrogen-copper compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-copper compound@boron nitride hybrid added was 10 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0048] Example 3

[0049] 68.0 g of epoxy resin, 15.0 g of the organophosphorus-nitrogen-copper compound@boron nitride hybrid prepared according to Example 1, and 17.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare the organophosphorus-nitrogen-copper compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-copper compound@boron nitride hybrid added was 15 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0050] Example 4

[0051] In Example 1, 12.1 g of copper nitrate trihydrate was dissolved in 100 mL of anhydrous ethanol, and 13.5 g of ferric nitrate nonahydrate was dissolved in 100 mL of anhydrous ethanol. The rest of the synthesis method was the same to prepare organophosphorus-nitrogen-iron compound@boron nitride hybrid FeDMZ@BN (wherein the mass ratio of organophosphorus-nitrogen-iron compound to boron nitride microflakes was 1:1).

[0052] 76.0 g of epoxy resin, 5.0 g of organophosphorus-nitrogen-iron compound@boron nitride hybrid, and 19.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare an organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 5 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0053] Example 5

[0054] 72.0 g of epoxy resin, 10.0 g of the organophosphorus-nitrogen-iron compound@boron nitride hybrid prepared according to Example 4, and 18.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare the organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 10 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0055] Example 6

[0056] 68.0 g of epoxy resin, 15.0 g of the organophosphorus-nitrogen-iron compound@boron nitride hybrid prepared according to Example 4, and 17.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare the organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 15 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0057] Example 7

[0058] In Example 1, 12.1 g of copper nitrate trihydrate was dissolved in 100 mL of anhydrous ethanol, and 70 g of boron nitride microflakes (average size 5 μm) were dispersed in 200 mL of anhydrous ethanol. Instead, 13.5 g of ferric nitrate nonahydrate was dissolved in 100 mL of anhydrous ethanol, and 210 g of boron nitride microflakes (average size 5 μm) were dispersed in 200 mL of anhydrous ethanol. All other synthesis methods were the same as in Example 1 to prepare organophosphorus iron nitrogen compound@boron nitride hybrid FeDMZ@BN (wherein the mass ratio of organophosphorus iron nitrogen compound to boron nitride microflakes was 1:3).

[0059] 76.0 g of epoxy resin, 5.0 g of organophosphorus-nitrogen-iron compound@boron nitride hybrid, and 19.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare an organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 5 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0060] Example 8

[0061] 72.0 g of epoxy resin, 10.0 g of the organophosphorus-nitrogen-iron compound@boron nitride hybrid prepared according to Example 7, and 18.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare the organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 10 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0062] Example 9

[0063] 68.0 g of epoxy resin, 15.0 g of the organophosphorus-nitrogen-iron compound@boron nitride hybrid prepared according to Example 7, and 17.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare the organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 15 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0064] Example 10

[0065] In Example 1, 12.1 g of copper nitrate trihydrate was dissolved in 100 mL of anhydrous ethanol, and 70 g of boron nitride microflakes (average size 5 μm) were dispersed in 200 mL of anhydrous ethanol. Instead, 13.5 g of ferric nitrate nonahydrate was dissolved in 100 mL of anhydrous ethanol, and 420 g of boron nitride microflakes (average size 5 μm) were dispersed in 200 mL of anhydrous ethanol. All other synthesis methods were the same as in Example 1 to prepare organophosphorus-nitrogen-iron compound@boron nitride hybrid FeDMZ@BN (wherein the mass ratio of organophosphorus-nitrogen-iron compound to boron nitride microflakes was 1:6).

[0066] 76.0 g of epoxy resin, 5.0 g of organophosphorus-nitrogen-iron compound@boron nitride hybrid, and 19.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare an organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 5 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0067] Example 11

[0068] 72.0 g of epoxy resin, 10.0 g of the organophosphorus-nitrogen-iron compound@boron nitride hybrid prepared according to Example 10, and 18.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare the organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 10 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0069] Example 12

[0070] 68.0 g of epoxy resin, 15.0 g of the organophosphorus-nitrogen-iron compound@boron nitride hybrid prepared according to Example 10, and 17.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, injected into a polytetrafluoroethylene mold, and cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h to prepare the organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 15 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0071] Compare with Example 1

[0072] 80.0 g of epoxy resin was added to a stainless steel cup and heated to 100 °C with continuous stirring. Then, 20 g of 4,4′-diaminodiphenylmethane curing agent was added and stirring continued for 3 min. The mixture was then vacuumed at 100 °C for 5 min, and finally poured into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for 2 h, yielding the unmodified epoxy resin material. The composition, flame retardant properties, and thermal conductivity of the epoxy resin material are shown in Tables 1, 2, and 3.

[0073] 80.0 g of epoxy resin and 18.0 g of 4,4′-diaminodiphenylmethane curing agent were mixed evenly according to the method in Example 1, and then injected into a polytetrafluoroethylene mold. The mixture was cured at 120 °C for 2 h, followed by curing at 150 °C for another 2 h to prepare an organophosphorus-nitrogen-iron compound@boron nitride hybrid epoxy resin composite material (the amount of organophosphorus-nitrogen-iron compound@boron nitride hybrid added was 10 wt%). The composition, flame retardant properties, and thermal conductivity of the epoxy resin composite material are shown in Tables 1, 2, and 3.

[0074] As shown in Table 2, the addition of organophosphorus nitrogen metal coordination compounds@boron nitride hybrids to epoxy resins significantly enhances their flame retardant properties. At an addition amount of 15 wt%, organophosphorus nitrogen iron compounds@boron nitride hybrids with loading ratios of 1:1, 1:3, and 1:6 show a more significant improvement in flame retardant properties than organophosphorus nitrogen copper compounds, with both LOI and flame retardant rating improved. Furthermore, increasing the loading ratio or the amount of modified boron nitride added also enhances the flame retardant properties of the epoxy resin composites.

[0075] As shown in Table 3, with the same addition amount (15 wt%), Examples 3 and 6 demonstrate that the organophosphorus nitrogen-iron compound@boron nitride hybrid improves the thermal conductivity of epoxy resin composites better than the organophosphorus nitrogen-copper compound@boron nitride hybrid. Examples 6, 9, and 12 show that as the loading ratio of organophosphorus nitrogen-iron compound to boron nitride microflakes decreases, i.e., the actual addition amount of boron nitride microflakes increases, the thermal conductivity of the epoxy resin composite increases sequentially, ranging from 0.31 to 0.47 W / (m·K). The organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite can significantly improve the thermal conductivity of the composite while meeting the UL-94 V-0 flame retardant rating. The thermally conductive and flame-retardant epoxy resin composite material described in this invention is expected to be widely used in thermal management fields such as new energy battery packaging materials and electronic component packaging materials.

[0076] Table 1 Formulation table of organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composites for examples and control examples

[0077]

[0078] Note: Organophosphorus-nitrogen-copper compound@boron nitride hybrid: CuDMZ@BN; Organophosphorus-nitrogen-iron compound@boron nitride hybrid: FeDMZ@BN; Epoxy resin: EP; 4,4′-diaminodiphenylmethane: DDM.

[0079] Table 2. Flame retardant properties of organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composites prepared in the examples and comparative examples.

[0080]

[0081] Table 3. A summary of the thermal conductivity of organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composites prepared in the examples and comparative examples.

[0082]

[0083] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. An organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material, characterized in that, The raw materials include the following components in parts by weight: 5-15 parts of organophosphorus nitrogen metal coordination compound@boron nitride micro flakes, 15-20 parts of curing agent, and bisphenol A type epoxy resin to make up to 100 parts; The organophosphorus nitrogen metal coordination compound@boron nitride hybrid was prepared by the following method: an ethanol solution of boron nitride micro flakes, an ethanol solution of the organophosphorus nitrogen metal coordination compound flame retardant, and an ethanol solution of nitrate were added to a reactor, and after uniform stirring and reaction, the product was centrifuged, washed with alcohol, and dried to obtain the organophosphorus nitrogen metal coordination compound@boron nitride hybrid. The organophosphorus-nitrogen metal coordination compound flame retardant is selected from organophosphorus-nitrogen copper coordination compounds or organophosphorus-nitrogen iron coordination compounds. In the organophosphorus nitrogen metal coordination compounds, the general structural formula of the organophosphorus nitrogen compound ligands is: In the formula, R is H or CH3; The preparation method of the organophosphorus nitrogen metal coordination compound flame retardant includes the following steps: S1: DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) was reacted with an equimolar amount of 1-vinylimidazolium compound under reflux at 140-180 °C for 4-12 hours to obtain organophosphorus nitrogen compound ligands; S2: After cooling, the organophosphorus nitrogen compound ligand is first dissolved in anhydrous ethanol to obtain an ethanol solution of the organophosphorus nitrogen compound ligand. Then, the ethanol solution of nitrate is slowly added and reacted at room temperature for 1 to 4 hours to obtain the organophosphorus nitrogen metal coordination compound. In S2, the nitrate is selected from copper nitrate or ferric nitrate.

2. The organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material according to claim 1, characterized in that, In S2, the molar ratio of the organophosphorus nitrogen compound ligand to the nitrate is 1:1 to 10:1, the reaction temperature is 25 to 95 °C, the reaction time is 1 to 24 h, and the pH is 1 to 10.

3. The organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material according to claim 1, characterized in that, The organophosphorus-nitrogen metal coordination compound flame retardant is an organophosphorus-nitrogen-iron coordination compound.

4. The organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material according to claim 1, characterized in that, The mass ratio of the organophosphorus nitrogen metal coordination compound to the boron nitride microflakes is 1:5 to 3:

1.

5. The organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material according to claim 1, characterized in that, The curing agent is selected from one or more of heterocyclic amine curing agents, aromatic amine curing agents, acid anhydride curing agents, or alicyclic amine curing agents.

6. A method for preparing an organophosphorus nitrogen metal coordination compound@boron nitride hybrid / epoxy resin composite material as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Weigh out the bisphenol A type epoxy resin, organophosphorus nitrogen metal coordination compound@boron nitride hybrid and curing agent according to the formula, stir evenly at 100 ℃ and put into polytetrafluoroethylene mold, and cure in different temperature ranges and time periods. The curing temperature is 100 ℃~150 ℃ and the curing time is 2~5 h.

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