Synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant and high-flame-retardant polymer composition prepared by using the same

Abstract

This application relates to the technical field of flame retardant preparation, in particular to a synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant and a highly flame-retardant polymer composition prepared by using the same. Synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant: After stirring ellagic acid, an acid-binding agent, and an organic solvent evenly, add diaminophosphoryl chloride at room temperature, continue to react at room temperature for 3 to 4 hours, and finally filter and drain the solvent to obtain the bio-based phosphorus-nitrogen synergistic flame retardant. The flame retardant in this application contains a super-large conjugated structure and has high thermal stability. Introducing phosphorus and nitrogen elements into its structure as a bio-based phosphorus-nitrogen synergistic flame retardant not only meets the requirements of green chemistry and sustainable development, promotes green and low-carbon development, but also can exert the flame retardant synergistic effect of phosphorus and nitrogen, enabling the polymer material to promote the formation of a carbonized layer during combustion, isolate oxygen and energy transfer, reduce the concentration of combustible gases and the release of toxic flue gas, and improve the flame retardant performance of the material.

Description

Technical Field

[0001] This application relates to the technical field of flame retardant preparation, and particularly to a synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant and a highly flame-retardant polymer composition prepared by using the same. Background Art

[0002] Fires can cause serious damage to the lives and property of the people. With the development of polymer material technology, polymer materials have been integrated into all aspects of modern life. However, the application of a large number of combustible and flammable polymer materials (polymer materials) makes them the main factor causing fires (especially urban building fires). In order to improve the flame retardant safety performance of polymer materials, the research on flame retardant functional additive materials has become an important and urgent research topic.

[0003] At present, the flame retardants that have been industrialized and widely used include metal oxide flame retardants and halogen-based flame retardants. However, each of the above four categories has its own defects in the actual application process. For example, the polarity difference between metal oxides and most polymer materials is huge, making it difficult to be fully dispersed inside the polymer materials, resulting in poor flame retardant effects; while the materials added with halogen-based flame retardants will release strong toxic and corrosive hydrogen halides during the combustion process. Although hydrogen halides have the effect of eliminating active free radicals generated by the combustion reaction, thereby slowing down or terminating the chain reaction of combustion and achieving the effect of flame retardant and fire prevention, the release of hydrogen halides will inevitably cause harm to the human body.

[0004] Phosphorus-based flame retardants and nitrogen-based flame retardants have the advantages of good flame retardant effects, safety and non-toxicity, and have received more and more attention in recent years. It is expected to replace metal oxide flame retardants and halogen-based flame retardants as the mainstream flame retardants in various fields of production and life. Research shows that the two elements of phosphorus and nitrogen have a synergistic flame retardant effect, and it is of great significance to develop phosphorus-nitrogen synergistic flame retardants.

[0005] A Chinese invention patent, application number 2024100619689, discloses a method for preparing a phosphorus-nitrogen synergistic flame retardant using cyanuric chloride, phosphorus spirocycle, 3-aminopropyltrimethoxysilane, etc. as raw materials. The prepared flame retardant contains three flame retardant elements of silicon, phosphorus, and nitrogen, which can play a synergistic flame retardant role. The flame retardant molecules have a certain ability to inhibit smoke release due to the presence of more silicon elements.

[0006] Another example is a Chinese invention patent, application number 2022114279999, which discloses a polyhydroxy cage-like phosphorus-nitrogen synergistic flame retardant. The prepared flame retardant has the advantages of good symmetry, high decomposition temperature, good compatibility with materials, being able to adapt to the processing of most materials, easy availability of raw materials, halogen-free and environmentally friendly, etc. It is easy to form carbon, has no melt dripping, low toxicity and low smoke during the combustion process, and has good flame retardant effects.

[0007] To meet the production requirements of industrialization, not only does the synthesized flame retardant need to have good flame retardant and fire prevention effects, but also the production cost of the flame retardant needs to be comprehensively considered. The flame retardant synthesis materials in the above-mentioned existing technologies are uniformly non-biological source raw materials (i.e., materials extracted from the petroleum industry), resulting in a relatively high production cost of the finally prepared flame retardant, which limits its application and promotion. The present invention uses renewable resources - biological source raw materials to synthesize a phosphorus-nitrogen synergistic flame retardant, ensuring that the prepared phosphorus-nitrogen synergistic flame retardant has good flame retardant and fire prevention safety, wide sources of synthetic raw materials, relatively low production costs, facilitating the promotion and application of the prepared phosphorus-nitrogen synergistic flame retardant. At the same time, the synthesis process meets the requirements of green chemistry and sustainable development, and can promote green and low-carbon development. Summary of the Invention

[0008] To solve the technical problems existing in the above-mentioned existing technologies, the present application provides a method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant and a highly flame-retardant polymer composition prepared by using the same. The present invention uses a biological source material - ellagic acid as the main synthetic raw material, and uses simple chemical reactions to prepare a bio-based phosphorus-nitrogen synergistic flame retardant. The preparation method is simple and easy to operate, the reaction conditions are mild, the sources of synthetic raw materials are wide, and the production cost is relatively low. That is, the prepared bio-based phosphorus-nitrogen synergistic flame retardant has good flame retardant and fire prevention safety, and has relatively low production costs, facilitating the promotion and application of the phosphorus-nitrogen synergistic flame retardant.

[0009] The method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant provided by the present application is achieved through the following technical solutions:

[0010] A bio-based phosphorus-nitrogen synergistic flame retardant is made from ellagic acid, diaminophosphoryl chloride, an acid-binding agent, and an organic solvent.

[0011] The synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: Step 1, first add 10 parts by mass of ellagic acid to a reaction flask, and then sequentially add 10 - 80 parts by mass of an acid-binding agent and 100 - 300 parts by mass of an organic solvent to the reaction flask, and stir evenly to obtain a mixed solution; Step 2, at room temperature, add 10 - 80 parts by mass of diaminophosphoryl chloride dropwise to the mixed solution in Step 1. After the addition of diaminophosphoryl chloride is completed, continue to react at room temperature for 3 - 4 hours; Step 3, after the reaction is completed, filter the reaction solution in the reaction flask to remove solid filter residues, and remove the organic solvent under reduced pressure to obtain the target product - a bio-based phosphorus-nitrogen synergistic flame retardant.

[0012] Preferably, the acid-binding agent is an inorganic alkali metal carbonate and / or an organic base.

[0013] Preferably, the acid-binding agent is at least one of triethylamine, pyridine, 4-dimethylaminopyridine, sodium carbonate, and potassium carbonate.

[0014] Preferably, the organic solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphoramide, tetrahydrofuran, 1,4-dioxane, chloroform, N-methylpyrrolidone, and xylene.

[0015] Preferably, the general structural formula of the diamino phosphoryl chloride is as follows: , wherein R1, R2, R3, and R4 are independently selected from one of hydrogen, C1-C20 alkyl, aryl, alkenyl, alkynyl, alkoxy, hydroxyl, ester, and hydroxyalkyl.

[0016] Preferably, the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant is as follows, , wherein R is independently selected from one of hydrogen, C1-C20 alkyl, aryl, alkenyl, alkynyl, alkoxy, hydroxyl, ester, and hydroxyalkyl.

[0017] Preferably, the diamino phosphoryl chloride is one of bis(N,N-dimethylamino)phosphoryl chloride, bis(diethylamino)phosphoryl chloride, and bis(diphenylamino)phosphoryl chloride.

[0018] Preferably, R in the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant is independently selected from one of methyl, ethyl, and aryl.

[0019] A highly flame-retardant polymer composition prepared by a synthesis method using a bio-based phosphorus-nitrogen synergistic flame retardant provided by this application is achieved through the following technical solutions:

[0020] A highly flame-retardant polymer composition prepared by using a bio-based phosphorus-nitrogen synergistic flame retardant, which is made of the following raw materials in parts by mass: 0.5-1.5 parts of the bio-based phosphorus-nitrogen synergistic flame retardant, 98.5-99.5 parts of a polymer material; the polymer material is one of polylactic acid resin, polyurethane resin, epoxy resin, acrylic resin, and phenolic resin.

[0021] Further preferably, the highly flame-retardant polymer composition prepared by the synthesis method of using the bio-based phosphorus-nitrogen synergistic flame retardant is made of the following raw materials in parts by mass: 0.5-1.5 parts of bio-based phosphorus-nitrogen synergistic flame retardant, 0.05-0.2 parts of synergist, and 98.5-99.5 parts of polymer material; the polymer material is one of polylactic acid resin, polyurethane resin, epoxy resin, acrylic resin, and phenolic resin; the mass ratio of the bio-based phosphorus-nitrogen synergistic flame retardant to the synergist in the highly flame-retardant polymer composition is (9-19):1; the synergist is at least one of carbon nanotubes grafted with aluminum hydroxide on the surface, carbon nanotubes grafted with magnesium hydroxide on the surface, and carbon nanotubes grafted with zinc hydroxide on the surface; or the synergist is at least one of carbon nanotubes grafted with aluminum hydroxide on the surface, carbon nanotubes grafted with magnesium hydroxide on the surface, and carbon nanotubes grafted with zinc hydroxide on the surface combined with zinc borate whiskers to form a mixed synergist.

[0022] The phosphorus-nitrogen synergistic flame retardant in this application can effectively improve the flame retardancy and fire prevention performance of the polymer composition and has good cost economy.

[0023] Compared with the existing phosphorus-nitrogen synergistic flame retardants, the ellagic acid-based phosphorus-nitrogen synergistic flame retardant disclosed in the present invention has the following advantages:

[0024] 1) The present invention synthesizes the phosphorus-nitrogen synergistic flame retardant using bio-derived raw materials, ensuring that the prepared phosphorus-nitrogen synergistic flame retardant has good flame retardancy and fire prevention safety, and the synthetic raw materials are widely sourced, with relatively low production costs, facilitating the popularization and application of the prepared phosphorus-nitrogen synergistic flame retardant. At the same time, the synthesis process meets the requirements of green chemistry and sustainable development, and can promote green and low-carbon development.

[0025] 2) The present invention uses renewable resources of biological origin as raw materials, which meets the requirements of green chemistry and sustainable development, can promote green and low-carbon development, and is of great significance.

[0026] 3) The preparation method provided by the present invention only requires simple operations and is easy to implement, which is beneficial to reducing the total production cost.

[0027] 4) The flame retardant structure of the present invention contains the super-large conjugated structure of ellagic acid, endowing it with high thermal stability and carbon-forming performance. The introduction of phosphorus and nitrogen elements as bio-based phosphorus-nitrogen synergistic flame retardants in the flame retardant structure can exert the flame retardant synergistic effect, promote the formation of a carbonized layer, isolate oxygen and energy transfer, reduce the concentration of combustible gases and the release of toxic flue gas, and thus endow the prepared flame retardant with excellent ability to improve the flame retardancy and safety of polymer materials.

[0028] 5) The phosphorus-nitrogen synergistic flame retardant in the present invention has excellent compatibility and is suitable for the flame retardant modification of various general polymer materials. Description of the Drawings

[0029] Figure 1 It is a diagram showing the reaction equation of the bio-based phosphorus-nitrogen synergistic flame retardant in Example 1 of the present invention.

[0030] Figure 2 It is a diagram showing the reaction equation of the bio-based phosphorus-nitrogen synergistic flame retardant in Example 2 of the present invention.

[0031] Figure 3 It is a diagram showing the reaction equation of the bio-based phosphorus-nitrogen synergistic flame retardant in Example 3 of the present invention.

[0032] Figure 4 It is the nuclear magnetic resonance hydrogen spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant A1 prepared in Example 1 of the present invention.

[0033] Figure 5 It is the nuclear magnetic resonance phosphorus spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant A1 prepared in Example 1 of the present invention.

[0034] Figure 6 It is the infrared spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant A1 prepared in Example 1 of the present invention. Detailed implementation manners

[0035] To further understand the present invention, the preferred implementation manners of the present invention will be described below in conjunction with examples and comparative examples. Examples

[0036] A bio-based phosphorus-nitrogen synergistic flame retardant is made from ellagic acid, diaminophosphoryl chloride, an acid-binding agent, and an organic solvent.

[0037] A synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant is as follows:

[0038] Step 1: First, add 10 parts by mass of ellagic acid to a reaction flask, and then successively add 10-80 parts by mass of an acid-binding agent and 100-300 parts by mass of an organic solvent to the reaction flask, and stir evenly to obtain a mixed solution;

[0039] Step 2: At room temperature, add 10-80 parts by mass of diaminophosphoryl chloride dropwise to the mixed solution in Step 1. After the addition of diaminophosphoryl chloride is completed, continue to react at room temperature for 3-4 hours;

[0040] Step 3: After the reaction is completed, filter the reaction solution in the reaction flask to remove the solid filter residue, and remove the organic solvent by reduced pressure distillation to obtain the target product - the bio-based phosphorus-nitrogen synergistic flame retardant.

[0041] Preferably, the acid-binding agent is an inorganic alkali metal carbonate and / or an organic base. Further preferably, the acid-binding agent is at least one of triethylamine, pyridine, 4-dimethylaminopyridine, sodium carbonate, and potassium carbonate.

[0042] Preferably, the organic solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphoramide, tetrahydrofuran, 1,4-dioxane, chloroform, N-methylpyrrolidone, and xylene.

[0043] Preferably, the general structural formula of the diamino phosphoryl chloride is as follows: , wherein, R1, R2, R3, and R4 are independently selected from one of hydrogen, C1-C20 alkyl, aryl, alkenyl, alkynyl, alkoxy, hydroxyl, ester group, and hydroxyalkyl.

[0044] More preferably, the diamino phosphoryl chloride is one of bis(N,N-dimethylamino)phosphoryl chloride, bis(diethylamino)phosphoryl chloride, and bis(diphenylamino)phosphoryl chloride.

[0045] Preferably, the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant is as follows, , wherein, R is independently selected from one of hydrogen, C1-C20 alkyl, aryl, alkenyl, alkynyl, alkoxy, hydroxyl, ester group, and hydroxyalkyl. Preferably, R in the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant is independently selected from one of methyl, ethyl, and aryl.

[0046] A highly flame-retardant polymer composition prepared using a bio-based phosphorus-nitrogen synergistic flame retardant, which is made from the following raw materials in parts by mass: 0.5-1.5 parts of the bio-based phosphorus-nitrogen synergistic flame retardant, 98.5-99.5 parts of a polymer material, and the polymer material is one of polylactic acid resin, polyurethane resin, epoxy resin, acrylic resin, and phenolic resin.

[0047] More preferably, a highly flame-retardant polymer composition prepared using a bio-based phosphorus-nitrogen synergistic flame retardant, which is made from the following raw materials in parts by mass: 0.5-1.5 parts of the bio-based phosphorus-nitrogen synergistic flame retardant, 0.05-0.2 parts of a synergist, 98.5-99.5 parts of a polymer material. The polymer material is one of polylactic acid resin, polyurethane resin, epoxy resin, acrylic resin, and phenolic resin. The mass ratio of the bio-based phosphorus-nitrogen synergistic flame retardant to the synergist in the highly flame-retardant polymer composition is (9-19):1. Preferably, the mass ratio of the bio-based phosphorus-nitrogen synergistic flame retardant to the synergist in the highly flame-retardant polymer composition is 15:1. The synergist is at least one of carbon nanotubes grafted with aluminum hydroxide on the surface, carbon nanotubes grafted with magnesium hydroxide on the surface, and carbon nanotubes grafted with zinc hydroxide on the surface. Or the synergist is at least one of carbon nanotubes grafted with aluminum hydroxide on the surface, carbon nanotubes grafted with magnesium hydroxide on the surface, and carbon nanotubes grafted with zinc hydroxide on the surface in combination with zinc borate whiskers to form a mixed synergist.

[0048] Example 1: The synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: Weigh 10 parts of ellagic acid and add it to a reaction flask. Then, add 40 parts of pyridine and 200 parts of dimethyl sulfoxide to the reaction flask in sequence and stir evenly. Subsequently, measure 40 parts of bis(dimethylamino)phosphoryl chloride (bis(N,N-dimethylamino)phosphoryl chloride, molecular formula: C4H12ClN2OP, molecular weight 170.04, CAS: 1605-65-8), and add it dropwise to the reaction flask at room temperature. Subsequently, continue the reaction at room temperature for 3 hours. After the reaction is completed, filter the reaction solution to remove the solid filter residue, and distill off dimethyl sulfoxide under reduced pressure to obtain the bio-based phosphorus-nitrogen synergistic flame retardant A1. The yield of the bio-based phosphorus-nitrogen synergistic flame retardant synthesis method provided in Example 1 is 92%.

[0049] Example 2: The synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: Weigh 10 parts of ellagic acid and add it to a reaction flask. Then, add 40 parts of pyridine and 200 parts of dimethyl sulfoxide to the reaction flask in sequence and stir evenly. Subsequently, measure 40 parts of bis(diethylamino)phosphoryl chloride (molecular formula C8H20ClN2OP, molecular weight 226.684, CAS number: 1794-24-7), and add it dropwise to the reaction flask at room temperature. Subsequently, continue the reaction at room temperature for 3 hours. After the reaction is completed, filter the reaction solution to remove the solid filter residue, and distill off dimethyl sulfoxide under reduced pressure to obtain the bio-based phosphorus-nitrogen synergistic flame retardant A2. The yield of the bio-based phosphorus-nitrogen synergistic flame retardant synthesis method provided in Example 2 is 85%.

[0050] Example 3: The synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: Weigh 10 parts of ellagic acid and add it to a reaction flask. Then, add 40 parts of pyridine and 200 parts of dimethyl sulfoxide to the reaction flask in sequence and stir evenly. Subsequently, measure 40 parts of bis(diphenylamino)phosphoryl chloride (purchased from Henan Wenhua Chemical Co., Ltd., CAS number: 95489-12-6), and add it dropwise to the reaction flask at room temperature. Subsequently, continue the reaction at room temperature for 3 hours. After the reaction is completed, filter the reaction solution to remove the solid filter residue, and distill off dimethyl sulfoxide under reduced pressure to obtain the bio-based phosphorus-nitrogen synergistic flame retardant A3. The yield of the bio-based phosphorus-nitrogen synergistic flame retardant synthesis method provided in Example 3 is 94%.

[0051] Analysis was carried out on the flame retardant A1 prepared in Example 1:

[0052] Figure 4 This is the nuclear magnetic resonance hydrogen spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant prepared in Example 1 of the present invention. The peaks in the range of 7.0 - 8.0 ppm can be attributed to the resonance peaks of the hydrogen on the conjugated structure of the benzene ring of ellagic acid; the resonance peak at 2.8 ppm can be attributed to the peak of the methyl group.

[0053] Figure 5The phosphorus nuclear magnetic resonance spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant prepared in Example 1 of the present invention. Due to the symmetry of the molecular structure of flame retardant A1, although it has four phosphorus atoms, they are only in two chemical environments, so only two resonance peaks appear in the phosphorus spectrum, and the chemical shifts are 11.8 ppm and 0.8 ppm respectively.

[0054] Figure 6 The infrared spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant prepared in Example 1 of the present invention, where the peak at 1721 cm -1 is the resonance absorption peak of the lactone group, and the peaks in the range of 1550 - 1450 cm -1 can be attributed to the resonance absorption peak of the benzene ring, the peak at 1258 cm -1 is the resonance absorption peak of P=O, and the peak at 908 cm -1 is the absorption peak of the P-N bond.

[0055] Example 4: A polylactic acid composite material prepared by using the synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is made of 0.5 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1 and 99.5 g of polylactic acid resin.

[0056] The preparation method of a polylactic acid composite material prepared by using the synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is as follows: Add 99.5 g of pure polylactic acid PLA (CAS: 26100 - 51 - 6, molecular weight 10,000, purchased from Shanghai Yuanye Bio-Technology Co., Ltd.) and 0.5 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1 into a high-speed blender, and premix for 5 min at a rotation speed of 300 rpm / min to obtain a premix. Then, place the obtained premix in a twin-screw extruder, melt extrude, draw, cool, and pelletize at 190 °C, and finally dry to obtain the pellets of the polylactic acid composite material PLA0.5.

[0057] The difference between Example 5 and Example 4 is that: A polylactic acid composite material prepared by using the synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is made of 1 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1 and 99 g of polylactic acid resin.

[0058] The difference between Example 6 and Example 4 is that: A polylactic acid composite material prepared by using the synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is made of 1.5 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1 and 98.5 g of polylactic acid resin.

[0059] The difference between Example 7 and Example 4 is that: A polylactic acid composite material prepared by using the synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is made of 1 g of the bio-based phosphorus-nitrogen synergistic flame retardant A2 in Example 2 and 99 g of polylactic acid resin.

[0060] Example 8 is different from Example 4 in that a polylactic acid composite material prepared by a synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant is made of 1 g of the bio-based phosphorus-nitrogen synergistic flame retardant A3 in Example 3 and 99 g of polylactic acid resin.

[0061] Example 9 is different from Example 4 in that a polylactic acid composite material prepared by a synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant is made of 0.9 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1, 0.1 g of a synergist, and 99 g of polylactic acid resin. The synergist is carbon nanotubes with aluminum hydroxide grafted on the surface.

[0062] The preparation method of carbon nanotubes with aluminum hydroxide grafted on the surface is as follows: S1. Dissolve 0.26 g of aluminum nitrate nonahydrate in 150 mL of distilled water, stir magnetically at 80 rpm / min for 0.5 h, then add 1.0 g of carbon nanotubes (industrial multi-walled carbon nanotubes TNIM6, with a diameter of 20 - 40 nm, a length of 10 - 30 microns, and a purity greater than 95 wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences). Stir magnetically at 80 rpm / min for 80 min, then add ammonia water with a concentration of 3.0 wt%. After the ammonia water is added until Al is completely precipitated, continue to stir magnetically at 80 rpm / min for 3.0 h, and let it stand for 24 h to obtain an Al(OH)3 / multi-walled carbon nanotube binary colloid; S2. Wash the prepared Al(OH)3 / multi-walled carbon nanotube binary colloid three times with distilled water, then filter it to obtain a solid powder. The obtained solid powder is placed in a vacuum drying oven and vacuum dried at 10 Pa and 125 °C for 12 h. Then it is transferred to an atmosphere tube furnace for calcination treatment. It is heated to 580 °C at a rate of 20 °C / min in an air atmosphere and calcined for 10 min. The obtained solid is placed in a planetary ball mill, zirconia is used as the grinding beads, and ball milled at a speed of 60 rpm for 45 min to obtain carbon nanotubes with aluminum hydroxide grafted on the surface. Aluminum hydroxide is grafted on the surface of the obtained carbon nanotubes with aluminum hydroxide grafted on the surface, and part of the aluminum hydroxide decomposes to form nano-scale alumina at the stage of calcination at 680 °C for 10 min, that is, a small amount of alumina is grafted on the surface of the carbon nanotubes, improving the compatibility with polar resins.

[0063] Example 10 is different from Example 9 in that the synergist is carbon nanotubes with magnesium hydroxide grafted on the surface.

[0064] The preparation method of carbon nanotubes grafted with magnesium hydroxide on the surface is as follows: S1. Dissolve 0.23 g of magnesium nitrate hexahydrate in 150 mL of distilled water and stir magnetically at 80 rpm / min for 0.5 h. Then add 1.0 g of carbon nanotubes (industrial multi-walled carbon nanotubes TNIM6, with a tube diameter of 20 - 40 nm, a length of 10 - 30 μm, a purity greater than 95 wt%, provided by Chengdu Organic Chemicals Co., Ltd., Chinese Academy of Sciences). After stirring magnetically at 80 rpm / min for 80 min, add ammonia water with a concentration of 3.0 wt%. After the addition of ammonia water until Al is completely precipitated, continue to stir magnetically at 80 rpm / min for 3.0 h, and let it stand for 24 h to obtain a Mg(OH)2 / multi-walled carbon nanotube binary colloid; S2. Wash the prepared Mg(OH)2 / multi-walled carbon nanotube binary colloid three times with distilled water and then filter it to obtain a solid powder. The obtained solid powder is placed in a vacuum drying oven and vacuum dried at 10 Pa and 125 °C for 12 h. Transfer it to an atmosphere tube furnace for calcination treatment. Under an air atmosphere, heat it to 400 °C at a rate of 20 °C / min and calcine for 10 min. The obtained solid is placed in a planetary ball mill, with zirconia as the grinding beads, and ball milled at a speed of 60 rpm for 45 min to obtain carbon nanotubes grafted with magnesium hydroxide on the surface.

[0065] The difference between Example 11 and Example 9 is that the synergist is carbon nanotubes grafted with zinc hydroxide on the surface.

[0066] The preparation method of carbon nanotubes grafted with zinc hydroxide on the surface is as follows: S1. Dissolve 0.25 g of zinc nitrate hexahydrate in 150 mL of distilled water and stir magnetically at 80 rpm / min for 0.5 h. Then add 1.0 g of carbon nanotubes (industrial multi-walled carbon nanotubes TNIM6, with a tube diameter of 20 - 40 nm, a length of 10 - 30 μm, a purity greater than 95 wt%, provided by Chengdu Organic Chemicals Co., Ltd., Chinese Academy of Sciences). After stirring magnetically at 80 rpm / min for 80 min, add ammonia water with a concentration of 3.0 wt%. After the addition of ammonia water until Al is completely precipitated, continue to stir magnetically at 80 rpm / min for 3.0 h, and let it stand for 24 h to obtain a Zn(OH)2 / multi-walled carbon nanotube binary colloid; S2. Wash the prepared Zn(OH)2 / multi-walled carbon nanotube binary colloid three times with distilled water and then filter it to obtain a solid powder. The obtained solid powder is placed in a vacuum drying oven and vacuum dried at 10 Pa and 95 °C for 16 h. Transfer it to an atmosphere tube furnace for calcination treatment. Under an air atmosphere, heat it to 150 °C at a rate of 10 °C / min and calcine for 5 min. The obtained solid is placed in a planetary ball mill, with zirconia as the grinding beads, and ball milled at a speed of 60 rpm for 45 min to obtain carbon nanotubes grafted with zinc hydroxide on the surface.

[0067] Example 12 is different from Example 9 in that the synergist is carbon nanotubes with surface-grafted aluminum hydroxide and zinc borate whiskers prepared in Example 9, and the mass ratio of carbon nanotubes with surface-grafted aluminum hydroxide to zinc borate whiskers is 4:1.

[0068] The preparation method of zinc borate whiskers is as follows: Add 50 mL of 0.1 mol / L Na2B4O7·10H2O solution and 1 g of trioctyl phosphate into a three-necked flask and mix evenly. Place the three-necked flask in an ultrasonic cleaner and ultrasonicate for 0.5 hours. On the premise of continuous stirring, add 10 mL of 2 mol / L Zn(NO3)2·6H2O solution to the three-necked flask at a dropping rate of 1 drop / 5 s. After reacting at a constant temperature of 70 °C for 0.5 hours, add 0.1 mol / L NaOH solution to the three-necked flask to adjust the pH of the solution to 8, and then continue to react at a constant temperature of 70 °C for 7 hours. After the reaction is completed, filter, wash, vacuum dry, and then place it in a planetary ball mill for ball milling and refinement. Dry ball mill at 80 rpm for 15 min to obtain zinc borate whiskers.

[0069] Comparative Example 1 is pure lactic acid PLA.

[0070] Comparative Example 2 is different from Example 4 in that a polylactic acid composite material prepared using a bio-based phosphorus-nitrogen synergistic flame retardant is composed of 0.9 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1, 0.1 g of carbon nanotubes (industrial multi-walled carbon nanotubes TNIM6, with a tube diameter of 20 - 40 nm, a length of 10 - 30 microns, and a purity greater than 95 wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences), and 99 g of polylactic acid resin.

[0071] The performance detection test is as follows:

[0072] 1. Flame retardancy evaluation: The pellets of the polylactic acid composite material are fully dried and then injection molded into test specimens (125 mm * 13 mm * 1.6 mm). Based on UL (Underwriters Laboratories)-94 (the standard is shown in Table 1), a 20 mm vertical burning test was carried out on the specimens to judge the flame retardancy grade of the specimens.

[0073] Table 1 Flame retardancy test UL-94 standard

[0074]

[0075] 2. Limiting oxygen index evaluation: The pellets of the polylactic acid composite material are fully dried and then injection molded into test specimens (100 mm * 6.5 mm * 3 mm). Use an oxygen index meter to evaluate the measured limiting oxygen index LOI of the specimens.

[0076] 3. Mechanical property evaluation: The pellets of the polylactic acid composite material were dried thoroughly and then injection-molded into test specimens. Subsequently, a 5569 Instron universal tensile testing machine was used to test its tensile properties in accordance with the national standard GB / T 1040.2-2006.

[0077] Table 2 is the test parameter table of the polylactic acid composite materials in Examples 4-12 and Comparative Examples 1-2.

[0078]

[0079] Combined with Examples 4-6 and Comparative Example 1 and Table 2, it can be seen that the bio-based phosphorus-nitrogen synergistic flame retardant in the present invention can endow the polylactic acid composite material with good flame retardant and fire safety performance at an addition amount of 1.0-1.5 wt%, reaching UL-94 V0.

[0080] Combined with Example 5 and Examples 7-8 and Table 2, it can be seen that the bio-based phosphorus-nitrogen synergistic flame retardants in Example 5 and Examples 7-8 can endow the polylactic acid composite material with good flame retardant and fire safety performance at an addition amount of 1.0 wt%, reaching UL-94 V0. At the same addition amount (1.0 wt%), the flame retardant performance of the polylactic acid composite material prepared with the bio-based phosphorus-nitrogen synergistic flame retardant in Example 8 is relatively good. The R group is a benzene ring structure. The introduction of nitrogen and phosphorus elements and the benzene ring structure into the bio-based phosphorus-nitrogen synergistic flame retardant can improve the overall flame retardant performance and high-temperature processing performance of the bio-based phosphorus-nitrogen synergistic flame retardant. Due to the introduction of the benzene ring structure in the bio-based phosphorus-nitrogen synergistic flame retardant in Example 8, the elongation at break of the polylactic acid composite material prepared is relatively poor compared to that of Example 5 and Example 7, while its tensile strength is relatively better.

[0081] Combined with Example 5, Examples 9-12 and Comparative Example 2 and Table 2, it can be seen that the carbon nanotubes grafted with metal hydroxides provided in the present invention can improve the overall flame retardant and fire safety performance of the polylactic acid composite material, that is, the carbon nanotubes grafted with metal hydroxides and the bio-based phosphorus-nitrogen synergistic flame retardant can play a good flame retardant effect when used in combination. The reasons are as follows: The metal hydroxides in the carbon nanotubes grafted with metal hydroxides decompose endothermically, reducing the heat feedback to the matrix and lowering the matrix temperature; the thermal decomposition products are water vapor, which is environmentally friendly and can dilute the oxygen concentration in the air; a dense metal oxide layer may be formed to hinder the transfer of energy and substances; and the carbon nanotubes in the carbon nanotubes grafted with metal hydroxides form a continuous network structure in the matrix, and the network structure forms a continuous and complete protective layer during combustion, which can improve the quality of the char layer. The char layer covers the surface of the sample, isolating and reducing the migration of volatile substances into the gas phase.

[0082] Combined with Example 5, Examples 9 - 12 and Comparative Example 2 and in conjunction with Table 2, it can be seen that the carbon nanotubes grafted with metal hydroxides on the surface provided in the present invention can improve the overall mechanical tensile properties of the polylactic acid composite material. The reason is that the carbon nanotubes grafted with metal hydroxides on the surface improve their own polarity and have good compatibility with the polylactic acid matrix, can be relatively dispersed inside the TPU matrix, and can improve the overall mechanical tensile properties of the polylactic acid composite material while enhancing the flame retardant and fire prevention performance.

[0083] The difference between Example 13 and Example 5 is that a TPU composite material prepared using a bio - based phosphorus - nitrogen synergistic flame retardant is made of 1 g of the bio - based phosphorus - nitrogen synergistic flame retardant A1 in Example 1 and 99 g of thermoplastic polyurethane elastomer TPU.

[0084] The preparation method of the TPU composite material is as follows: 99 g of thermoplastic polyurethane elastomer TPU (BASF TPU1195A) and 1 g of the bio - based phosphorus - nitrogen synergistic flame retardant A1 in Example 1 are added to a high - speed blender and premixed at a rotation speed of 300 rpm / min for 5 min to obtain a premix. Then, the obtained premix is placed in a twin - screw extruder, melt - extruded, drawn, cooled, and pelletized at 150 °C, and finally dried to obtain the pellets of the polylactic acid composite material TPU 1.0.

[0085] The difference between Example 14 and Example 5 is that a TPU composite material prepared using a bio - based phosphorus - nitrogen synergistic flame retardant is made of 0.9 g of the bio - based phosphorus - nitrogen synergistic flame retardant A1 in Example 1, 0.1 g of a synergist, and 99 g of thermoplastic polyurethane elastomer TPU. The synergist is the carbon nanotubes grafted with aluminum hydroxide prepared in Example 9.

[0086] Comparative Example 3 is pure thermoplastic polyurethane elastomer TPU resin TPU 1195A.

[0087] The difference between Comparative Example 4 and Example 14 is that a TPU composite material prepared using a bio - based phosphorus - nitrogen synergistic flame retardant is made of 0.9 g of the bio - based phosphorus - nitrogen synergistic flame retardant A1 in Example 1, 0.1 g of carbon nanotubes (industrial - grade multi - walled carbon nanotubes TNIM6, with a tube diameter of 20 - 40 nm, a length of 10 - 30 microns, and a purity greater than 95 wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) and 99 g of thermoplastic polyurethane elastomer TPU.

[0088] Table 3 is the test parameter table of the TPU composite materials in Examples 13 - 14 and Comparative Examples 3 - 4

[0089]

[0090] Combined with Example 13 and Comparative Example 3 and Table 3, it can be seen that the bio-based phosphorus-nitrogen synergistic flame retardant in the present invention can endow the TPU composite material with good flame retardant and fire safety performance at an addition amount of 1.0 wt%, reaching UL-94 V0 level.

[0091] Combined with Example 14 and Comparative Example 4 and Table 3, it can be seen that the carbon nanotubes grafted with metal hydroxides provided in the present invention can improve the overall flame retardant and fire safety performance of the TPU composite material, that is, the carbon nanotubes grafted with metal hydroxides and the bio-based phosphorus-nitrogen synergistic flame retardant can play a good flame retardant effect when used in combination. In addition, the carbon nanotubes grafted with metal hydroxides improve their own polarity and have good compatibility with the TPU matrix, and can be relatively dispersed inside the TPU matrix, which can improve the flame retardant and fire performance while improving the overall mechanical tensile performance of the TPU composite material.

[0092] The difference between Example 15 and Example 1 is that a phenolic resin composite material prepared using a bio-based phosphorus-nitrogen synergistic flame retardant is made of 1.0 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1 and 99 g of phenolic resin.

[0093] The preparation method of a phenolic resin composite material prepared using a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: 99 g of phenolic resin liquid is mixed evenly with 1.0 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1 and added to the corresponding mold, and then cured at 80 °C for 24 h, and finally demolded to obtain the phenolic resin composite material, and test specimens are prepared by this method.

[0094] The difference between Example 16 and Example 1 is that a phenolic resin composite material prepared using a bio-based phosphorus-nitrogen synergistic flame retardant is made of 0.9 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1, 0.1 g of a synergist, and 99 g of phenolic resin. The synergist is the carbon nanotubes grafted with aluminum hydroxide prepared in Example 9.

[0095] Comparative Example 5 is pure phenolic resin (purchased from Hangmo New Materials Group Co., Ltd.).

[0096] The difference between Comparative Example 6 and Example 16 is that a phenolic resin composite material prepared using a bio-based phosphorus-nitrogen synergistic flame retardant is made of 0.9 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1, 0.1 g of carbon nanotubes (industrial multi-walled carbon nanotubes TNIM6, with a diameter of 20-40 nm, a length of 10-30 microns, and a purity greater than 95 wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) and 99 g of phenolic resin.

[0097] Table 4 is the test parameter table of the phenolic resin composite materials in Examples 15-16 and Comparative Examples 5-6

[0098]

[0099] Combined with Example 15 and Comparative Example 5 and Table 4, it can be seen that the bio-based phosphorus-nitrogen synergistic flame retardant in the present invention can endow the phenolic resin composite with good flame retardant and fire safety performance at an addition amount of 1.0 wt%, reaching UL-94 V0 level.

[0100] Combined with Example 16 and Comparative Example 6 and Table 4, it can be seen that the carbon nanotubes grafted with metal hydroxides on the surface provided in the present invention can improve the overall flame retardant and fire safety performance of the phenolic resin composite, that is, the carbon nanotubes grafted with metal hydroxides on the surface and the bio-based phosphorus-nitrogen synergistic flame retardant can play a good flame retardant and fire prevention effect when used in combination.

[0101] Combined with Example 16 and Comparative Example 6 and Table 4, it can be seen that the carbon nanotubes grafted with metal hydroxides on the surface improve their own polarity and have good compatibility with the phenolic resin matrix, can be relatively dispersed inside the phenolic resin matrix, and can improve the overall mechanical tensile performance of the phenolic resin composite while enhancing the flame retardant and fire prevention performance.

[0102] In summary, the present invention uses the biogenic material - ellagic acid as the main synthetic raw material, and prepares the bio-based phosphorus-nitrogen synergistic flame retardant by simple chemical reactions. The preparation method is simple and easy to operate, the reaction conditions are mild, the synthetic raw materials are widely sourced, and the production cost is relatively low. That is, the prepared bio-based phosphorus-nitrogen synergistic flame retardant has good flame retardant and fire safety, and has a relatively low production cost, which is convenient for the popularization and application of the phosphorus-nitrogen synergistic flame retardant.

[0103] This specific embodiment is only an interpretation of the present application and does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant, characterized in that: The bio-based phosphorus-nitrogen synergistic flame retardant is made from ellagic acid, diaminophosphoryl chloride, acid-binding agent, and organic solvent; The acid-binding agent is pyridine; the organic solvent is dimethyl sulfoxide; the diaminophosphoryl chloride is bis(dimethylamino)phosphoryl chloride or bis(diethylamino)phosphoryl chloride or bis(diphenylamino)phosphoryl chloride; the synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is as follows: Step 1, first add 10 parts by mass of ellagic acid into a reaction flask, and then successively add 10 - 80 parts by mass of acid-binding agent and 100 - 300 parts by mass of organic solvent into the reaction flask, and stir evenly to obtain a mixed solution; Step 2, at room temperature, add 10 - 80 parts by mass of diaminophosphoryl chloride dropwise to the mixed solution in Step 1. After the addition of diaminophosphoryl chloride is completed, continue to react at room temperature for 3 - 4 hours; Step 3, after the reaction is completed, filter the reaction solution in the reaction flask to remove the solid filter residue, and remove the organic solvent under reduced pressure to obtain the target product - the bio-based phosphorus-nitrogen synergistic flame retardant; the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant is as follows: , wherein, R is methyl or ethyl or phenyl.

2. The synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 1, characterized in that: The specific steps are as follows: Weigh 10 parts of ellagic acid and add it into a reaction flask, then successively add 40 parts of pyridine and 200 parts of dimethyl sulfoxide into the reaction flask and stir evenly; then measure 40 parts of bis(dimethylamino)phosphoryl chloride and add it dropwise into the reaction flask at room temperature, and then continue to react at room temperature for 3 hours; after the reaction is completed, filter the reaction solution to remove the solid filter residue, and remove dimethyl sulfoxide under reduced pressure to obtain the bio-based phosphorus-nitrogen synergistic flame retardant A1. The yield of the provided synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is 92%; the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant A1 is as follows: 。 3. The synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 1, characterized in that: The specific steps are as follows: Weigh 10 parts of ellagic acid and add it into a reaction flask, then successively add 40 parts of pyridine and 200 parts of dimethyl sulfoxide into the reaction flask and stir evenly; then measure 40 parts of bis(diethylamino)phosphoryl chloride and add it dropwise into the reaction flask at room temperature, and then continue to react at room temperature for 3 hours; after the reaction is completed, filter the reaction solution to remove the solid filter residue, and remove dimethyl sulfoxide under reduced pressure to obtain the bio-based phosphorus-nitrogen synergistic flame retardant A2. The yield of the provided synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is 85%; the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant A2 is as follows: 。 4. The synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 1, characterized in that: The specific steps are as follows: Weigh 10 parts of ellagic acid and add it into a reaction flask, then successively add 40 parts of pyridine and 200 parts of dimethyl sulfoxide into the reaction flask and stir evenly; then measure 40 parts of bis(diphenylamino)phosphoryl chloride and add it dropwise into the reaction flask at room temperature, and then continue to react at room temperature for 3 hours; after the reaction is completed, filter the reaction solution to remove the solid filter residue, and remove dimethyl sulfoxide under reduced pressure to obtain the bio-based phosphorus-nitrogen synergistic flame retardant A3. The yield of the provided synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is 94%; the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant A3 is as follows: 。 5. A highly flame-retardant polymer composition prepared using a bio-based phosphorus-nitrogen synergistic flame retardant, characterized in that: The high-flame-retardant polymer composition is made from the following raw materials in parts by mass: 0.5 - 1.5 parts of bio-based phosphorus-nitrogen synergistic flame retardant, 98.5 - 99.5 parts of polymer material; The polymer material is one of polylactic acid resin, polyurethane resin, epoxy resin, acrylic resin, and phenolic resin; The bio-based phosphorus-nitrogen synergistic flame retardant is selected from bio-based phosphorus-nitrogen synergistic flame retardant A1, bio-based phosphorus-nitrogen synergistic flame retardant A2, or bio-based phosphorus-nitrogen synergistic flame retardant A3; The structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant A1 is as follows: ； The structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant A2 is as follows: ； The structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant A3 is as follows: 。 6. A highly flame-retardant polymer composition prepared using a bio-based phosphorus-nitrogen synergistic flame retardant, characterized in that: The highly flame-retardant polymer composition is made from the following raw materials in parts by mass: 0.5 - 1.5 parts of the bio-based phosphorus-nitrogen synergistic flame retardant, 0.05 - 0.2 parts of the synergist, and 98.5 - 99.5 parts of the polymer material; the polymer material is one of polylactic acid resin, polyurethane resin, epoxy resin, acrylic resin, and phenolic resin; the mass ratio of the bio-based phosphorus-nitrogen synergistic flame retardant to the synergist in the highly flame-retardant polymer composition is (9 - 19):1; the synergist is at least one of carbon nanotubes grafted with aluminum hydroxide on the surface, carbon nanotubes grafted with magnesium hydroxide on the surface, and carbon nanotubes grafted with zinc hydroxide on the surface; or the synergist is a mixed synergist formed by at least one of carbon nanotubes grafted with aluminum hydroxide on the surface, carbon nanotubes grafted with magnesium hydroxide on the surface, and carbon nanotubes grafted with zinc hydroxide on the surface in combination with zinc borate whiskers.

Images