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

Abstract

The invention relates to the technical field of preparation of flame retardants, in particular to a synthetic method of a bio-based phosphorus-nitrogen synergistic flame retardant and a high-flame-retardant polymer composition prepared by using the bio-based phosphorus-nitrogen synergistic flame retardant. The synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant comprises the following steps: uniformly stirring the ellagic acid, the acid-binding agent and the organic solvent, then adding the diamido phosphoryl chloride at room temperature, continuously reacting for 3-4 hours at room temperature, and finally filtering and draining the solvent to obtain the bio-based phosphorus-nitrogen synergistic flame retardant. The flame retardant contains a super-large conjugated structure and has very high thermal stability, phosphorus and nitrogen elements are introduced into the structure to serve as the bio-based phosphorus-nitrogen synergistic flame retardant, the requirements of green chemistry and sustainable development are met, green and low-carbon development is promoted, the phosphorus-nitrogen synergistic flame retardant gain effect can be achieved, and the flame retardant efficiency is improved. And in the combustion process of the high polymer material, the formation of a carbonization layer is promoted, oxygen and energy transfer are isolated, the concentration of combustible gas is reduced, the release of toxic smoke is reduced, and the flame retardant property of the material is improved.

Description

Technical Field

[0001] The present application relates to the technical field of flame retardant preparation, and in particular to a method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant and a highly flame-retardant polymer composition prepared using the same. Background Art

[0002] Fire can cause serious damage to people's lives and property safety. 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 flammable and combustible polymer materials (polymer materials) has made them the main factor causing fires (especially urban building fires). In order to improve the flame retardant safety performance of polymer materials, the research of flame retardant additive materials has become an important and urgent research topic.

[0003] At present, flame retardants that have been industrialized and widely used include metal oxide flame retardants and halogen flame retardants. However, the above four categories have their own defects in actual application. For example, the polarity of metal oxides is very different from that of most polymer materials, making it difficult to fully disperse in polymer materials, resulting in poor flame retardant effects; and materials with halogen flame retardants will release highly toxic and corrosive hydrogen halides during combustion. Although hydrogen halides have the effect of eliminating active free radicals produced by combustion reactions, thereby slowing down or terminating the chain reaction of combustion and achieving flame retardant and fireproof effects, 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 effect, safety and non-toxicity. They have received more and more attention in recent years and are expected to replace metal oxide flame retardants and halogen flame retardants as mainstream flame retardants in various fields of production and life. Studies have shown that phosphorus and nitrogen have a synergistic flame retardant effect, and the development of phosphorus-nitrogen synergistic flame retardants is of great significance.

[0005] The Chinese invention patent, application number 2024100619689, discloses a method of 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, silicon, phosphorus, and nitrogen, which can play a synergistic flame retardant role. The flame retardant molecules contain a large amount of silicon elements, which give them a certain ability to inhibit smoke release.

[0006] Another example is a polyhydroxy caged phosphorus-nitrogen synergistic flame retardant disclosed in the Chinese invention patent application number 2022114279999. The prepared flame retardant has good symmetry, high decomposition temperature, good compatibility with materials, can adapt to the processing of most materials, and the raw materials are easy to obtain. It is halogen-free and environmentally friendly. It is easy to form carbon during the combustion process, has no droplets, low toxicity and low smoke, and has a good flame retardant effect.

[0007] In order to meet the needs of industrial production, not only is it required that the synthesized flame retardant has good flame retardant and fireproofing effects, but the production cost of the flame retardant also needs to be comprehensively considered. The flame retardant synthetic materials in the above-mentioned prior art are uniformly non-biological raw materials (i.e. materials extracted from the petroleum industry), which leads to a high production cost of the final prepared flame retardant, thereby limiting its application and promotion. The present invention uses renewable resources-biological raw materials to synthesize phosphorus-nitrogen synergistic flame retardants, ensuring that the prepared phosphorus-nitrogen synergistic flame retardant has good flame retardant and fireproof safety, and the source of synthetic raw materials is wide, and the production cost is relatively low, which is convenient for 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] In order to solve the technical problems existing in the above-mentioned prior art, the present application provides a method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant and a highly flame-retardant polymer composition prepared using the same. The present invention uses ellagic acid, a biological source material, as the main synthetic raw material, and uses a simple chemical reaction to prepare the bio-based phosphorus-nitrogen synergistic flame retardant. The preparation method is simple and easy to operate, the reaction conditions are mild, the source of synthetic raw materials is 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 safety, and has a relatively low production cost, which is convenient for the promotion and application of phosphorus-nitrogen synergistic flame retardants.

[0009] The present application provides a method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant, which is achieved through the following technical solutions: A bio-based phosphorus-nitrogen synergistic flame retardant is prepared from ellagic acid, carbon dioxide diamine phosphoryl chloride, an acid-binding agent and an organic solvent.

[0010] A method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: step 1, first adding 10 parts by weight of ellagic acid into a reaction bottle, then sequentially adding 10 to 80 parts by weight of an acid binding agent and 100 to 300 parts by weight of an organic solvent into the reaction bottle, and stirring to obtain a mixed solution; step 2, dripping 10 to 80 parts by weight of diaminophosphoryl chloride into the mixed solution in step 1 at room temperature, and continuing to react for 3 to 4 hours at room temperature after the dripping of diaminophosphoryl chloride is completed; step 3, after the reaction is completed, filtering the reaction solution in the reaction bottle to remove the solid filter residue, and removing the organic solvent under reduced pressure to obtain the target product-bio-based phosphorus-nitrogen synergistic flame retardant.

[0011] Preferably, the acid binding agent is an inorganic alkali metal carbonate and / or an organic base.

[0012] Preferably, the acid binding agent is at least one of triethylamine, pyridine, 4-dimethylaminopyridine, sodium carbonate and potassium carbonate.

[0013] Preferably, the organic solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphoric triamide, tetrahydrofuran, 1,4-dioxane, chloroform, N-methylpyrrolidone and xylene.

[0014] Preferably, the diaminophosphoryl chloride has the following general structural formula: , wherein R1, R2, R3, and R4 are independently selected from one of hydrogen, C1-C20 alkyl, aryl, alkenyl, alkynyl, alkoxy, hydroxyl, ester, and hydroxyalkyl.

[0015] 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.

[0016] Preferably, the diaminophosphoryl chloride is one of bis(N,N-dimethylamino)phosphoryl chloride, bis(diethylamino)phosphoryl chloride and bis(diphenylamino)phosphoryl chloride.

[0017] 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.

[0018] The present application provides a highly flame-retardant polymer composition prepared by a synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant, which is achieved by the following technical scheme: A highly flame-retardant polymer composition prepared by using a bio-based phosphorus-nitrogen synergistic flame retardant comprises the following raw materials in parts by weight: 0.5-1.5 parts of a bio-based phosphorus-nitrogen synergistic flame retardant and 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.

[0019] Further preferably, the highly flame-retardant polymer composition prepared by the synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant comprises 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 with aluminum hydroxide grafted on the surface, carbon nanotubes with magnesium hydroxide grafted on the surface, and carbon nanotubes with zinc hydroxide grafted on the surface; or the synergist is at least one of carbon nanotubes with aluminum hydroxide grafted on the surface, carbon nanotubes with magnesium hydroxide grafted on the surface, and carbon nanotubes with zinc hydroxide grafted on the surface, combined with zinc borate whiskers to form a mixed synergist.

[0020] The phosphorus-nitrogen synergistic flame retardant in the present application can effectively improve the flame retardant and fireproof performance of the polymer composition and has good cost-effectiveness.

[0021] 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 improvements: 1) The present invention uses biological raw materials to synthesize the phosphorus-nitrogen synergistic flame retardant, which ensures that the prepared phosphorus-nitrogen synergistic flame retardant has good flame retardancy and fire safety, and the synthetic raw materials are from a wide range of sources, and the production cost is relatively low, which is convenient for 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.

[0022] 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.

[0023] 3) The preparation method provided by the present invention only requires simple operations and is easy to implement, which is conducive to reducing the total production cost.

[0024] 4) The flame retardant of the present invention contains an ultra-large conjugated structure of ellagic acid, which gives it high thermal stability and carbon-forming properties. The phosphorus and nitrogen elements are introduced into the structure of the flame retardant as a bio-based phosphorus-nitrogen synergistic flame retardant, which can exert the flame retardant gain effect of phosphorus-nitrogen synergism, promote the formation of a carbonized layer, isolate oxygen and energy transfer, reduce the concentration of combustible gases and reduce the release of toxic fumes, thereby giving the prepared flame retardant excellent ability to improve the flame retardant safety of polymer materials.

[0025] 5) The phosphorus-nitrogen synergistic flame retardant in the present invention has excellent compatibility and is suitable for flame retardant modification of various general polymer materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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.

[0027] Figure 2 This is a diagram showing the reaction equation of the bio-based phosphorus-nitrogen synergistic flame retardant in Example 2 of the present invention.

[0028] Figure 3 This is a diagram showing the reaction equation of the bio-based phosphorus-nitrogen synergistic flame retardant in Example 3 of the present invention.

[0029] Figure 4 This is the hydrogen nuclear magnetic resonance spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant A1 prepared in Example 1 of the present invention.

[0030] Figure 5This 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.

[0031] Figure 6 This is the infrared spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant A1 prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples and comparative examples. Example

[0033] A bio-based phosphorus-nitrogen synergistic flame retardant is prepared from ellagic acid, carbon dioxide diamine phosphoryl chloride, an acid-binding agent and an organic solvent.

[0034] A method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: Step 1, first add 10 parts by weight of ellagic acid into a reaction bottle, then add 10 to 80 parts by weight of an acid binding agent and 100 to 300 parts by weight of an organic solvent into the reaction bottle in sequence, and stir to obtain a mixed solution; Step 2: add 10 to 80 parts by weight of diaminophosphoryl chloride to the mixed solution in step 1 at room temperature. After the diaminophosphoryl chloride is added, continue the reaction at room temperature for 3 to 4 hours. Step 3: After the reaction is completed, the reaction liquid in the reaction bottle is filtered to remove the solid residue, and the organic solvent is removed under reduced pressure to obtain the target product - bio-based phosphorus-nitrogen synergistic flame retardant.

[0035] Preferably, the acid binding agent is an inorganic alkali metal carbonate and / or an organic base, and more preferably, the acid binding agent is at least one of triethylamine, pyridine, 4-dimethylaminopyridine, sodium carbonate and potassium carbonate.

[0036] Preferably, the organic solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphoric triamide, tetrahydrofuran, 1,4-dioxane, chloroform, N-methylpyrrolidone and xylene.

[0037] Preferably, the diaminophosphoryl chloride has the following general structure: , wherein R1, R2, R3, and R4 are independently selected from one of hydrogen, C1-C20 alkyl, aryl, alkenyl, alkynyl, alkoxy, hydroxyl, ester, and hydroxyalkyl.

[0038] More preferably, the diaminophosphoryl chloride is one of bis(N,N-dimethylamino)phosphoryl chloride, bis(diethylamino)phosphoryl chloride and bis(diphenylamino)phosphoryl chloride.

[0039] 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. 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.

[0040] A highly flame-retardant polymer composition prepared by using a bio-based phosphorus-nitrogen synergistic flame retardant comprises the following raw materials in parts by weight: 0.5-1.5 parts of a bio-based phosphorus-nitrogen synergistic flame retardant and 98.5-99.5 parts of a polymer material, wherein the polymer material is one of polylactic acid resin, polyurethane resin, epoxy resin, acrylic resin and phenolic resin.

[0041] Further preferably, a highly flame-retardant polymer composition prepared using a bio-based phosphorus-nitrogen synergistic flame retardant comprises the following raw materials in parts by mass: 0.5-1.5 parts of a bio-based phosphorus-nitrogen synergistic flame retardant, 0.05-0.2 parts of a synergist, and 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 with aluminum hydroxide grafted on the surface, carbon nanotubes with magnesium hydroxide grafted on the surface, and carbon nanotubes with zinc hydroxide grafted on the surface. Or the synergist is at least one of carbon nanotubes with aluminum hydroxide grafted on the surface, carbon nanotubes with magnesium hydroxide grafted on the surface, and carbon nanotubes with zinc hydroxide grafted on the surface, and is combined with zinc borate whiskers to form a mixed synergist.

[0042] Example 1: A method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: weigh 10 parts of ellagic acid and add it to a reaction bottle, then add 40 parts of pyridine and 200 parts of dimethyl sulfoxide to the reaction bottle in sequence, and stir evenly; then measure 40 parts of bis(dimethylamino)phosphoryl chloride (bis(N,N-dimethylamino)phosphonyl chloride, molecular formula: C4H12ClN2OP, molecular weight 170.04, CAS: 1605-65-8), and add it dropwise to the reaction bottle 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 residue, and remove the 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%.

[0043] Example 2: A method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: weigh 10 parts of ellagic acid and add it to a reaction bottle, then add 40 parts of pyridine and 200 parts of dimethyl sulfoxide to the reaction bottle in sequence, and stir evenly; then 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 bottle 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 residue, and remove the 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%.

[0044] Example 3: A method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: weigh 10 parts of ellagic acid and add it to a reaction bottle, then add 40 parts of pyridine and 200 parts of dimethyl sulfoxide to the reaction bottle in sequence, and stir evenly; then measure 40 parts of bis(diphenylamino)phosphoryl chloride (purchased from Henan Wenhua Chemical Co., Ltd., CAS No.: 95489-12-6) and add it dropwise to the reaction bottle 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 residue, and remove the 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%.

[0045] The flame retardant A1 prepared in Example 1 was analyzed: Figure 4 This is the hydrogen nuclear magnetic resonance 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 to 8.0 ppm can be attributed to the resonance peaks of 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.

[0046] Figure 5 This is the nuclear magnetic resonance phosphorus spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant prepared in Example 1 of the present invention. Since the molecular structure of flame retardant A1 is symmetrical, although it has four phosphorus atoms, they are only in two chemical environments. Therefore, only two resonance peaks are shown in the phosphorus spectrum, and the chemical shifts are 11.8 ppm and 0.8 ppm respectively.

[0047] Figure 6 This is the infrared spectrum of the bio-based phosphorus-nitrogen synergistic flame retardant prepared in Example 1 of the present invention, where 1721 cm -1 The peak at 1550-1450 cm -1 The peaks in the interval can be attributed to the resonance absorption peak of the benzene ring, 1258 cm -1 The peak at 908 cm is the resonance absorption peak of P=O.-1 The peak at is the absorption peak of PN bond.

[0048] Example 4: A polylactic acid composite material prepared by using the synthesis method of a 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.

[0049] A preparation method of a polylactic acid composite material prepared by a synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant is as follows: 99.5 g of pure polylactic acid PLA (CAS: 26100-51-6, molecular weight 1w, purchased from Shanghai Yuanye Biotechnology Co., Ltd.) and 0.5 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1 are added to a high-speed blender and mixed at a speed of 300 rpm / min for 5 minutes to obtain a premix, and then the obtained premix is ​​placed in a twin-screw extruder, melt-extruded at 190°C, drawn, cooled, granulated, and finally dried to obtain pellets of the polylactic acid composite material PLA0.5.

[0050] The difference between Example 5 and Example 4 is that a polylactic acid composite material prepared by using the 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 A1 in Example 1 and 99 g of polylactic acid resin.

[0051] The difference between Example 6 and Example 4 is that a polylactic acid composite material prepared by using the synthesis method of a 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.

[0052] The difference between Example 7 and Example 4 is that a polylactic acid composite material prepared by using the 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 A2 in Example 2 and 99 g of polylactic acid resin.

[0053] The difference between Example 8 and Example 4 is that a polylactic acid composite material prepared by using the 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.

[0054] The difference between Example 9 and Example 4 is that a polylactic acid composite material prepared by the 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 a polylactic acid resin. The synergist is a carbon nanotube with aluminum hydroxide grafted on the surface.

[0055] The preparation method of carbon nanotubes with surface grafted aluminum hydroxide is as follows: S1. 0.26g of aluminum nitrate nonahydrate is dissolved in 150mL of distilled water and magnetically stirred at 80rpm / min for 0.5h, then 1.0g of carbon nanotubes (industrial grade multi-walled carbon nanotubes TNIM6, diameter 20-40nm, length 10-30 microns, purity greater than 95wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) is added, magnetically stirred at 80rpm / min for 80min, then 3.0wt% ammonia water is added, and after the ammonia water is delivered until Al is completely precipitated, the magnetic stirring is continued at 80rpm / min for 3.0h, and the mixture is allowed to stand for 24h to obtain Al(OH)3 / multi-walled carbon nanotube binary colloid; S2. Al(OH)3 / multi-walled carbon nanotube binary colloid is prepared by distilled water. H) 3 / multi-walled carbon nanotube binary colloid is washed three times and then filtered to obtain solid powder, the obtained solid powder is placed in a vacuum drying oven, vacuum dried at 10Pa and 125°C for 12 hours, calcined in a transposed atmosphere tubular furnace, heated to 580°C at 20°C / min in an air atmosphere and calcined for 10 minutes, the obtained solid is placed in a planetary ball mill, zirconium oxide is used as grinding beads, and ball milled at 60rpm for 45 minutes to obtain carbon nanotubes with surface grafted with aluminum hydroxide, the surface of the obtained carbon nanotubes with surface grafted with aluminum hydroxide is grafted with aluminum hydroxide, and part of the aluminum hydroxide is decomposed to form nano-scale aluminum oxide during the calcination at 680°C for 10 minutes, that is, a small amount of aluminum oxide is grafted on the surface of the carbon nanotubes to improve the compatibility with polar resins.

[0056] The difference between Example 10 and Example 9 is that the synergist is carbon nanotubes with magnesium hydroxide grafted on the surface.

[0057] The preparation method of carbon nanotubes with surface grafted magnesium hydroxide is as follows: S1. 0.23 g of magnesium nitrate hexahydrate is dissolved in 150 mL of distilled water, and magnetically stirred at 80 rpm / min for 0.5 h, and then 1.0 g of carbon nanotubes (industrial grade multi-walled carbon nanotubes TNIM6, diameter 20-40 nm, length 10-30 microns, purity greater than 95 wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) is added, and magnetically stirred at 80 rpm / min for 80 min, and then 3.0 wt% ammonia water is added, and the ammonia water is delivered until Al is completely precipitated and magnetically stirred at 80 rpm / min for 3 hours. .0h, and let it stand for 24h to obtain Mg(OH)2 / multi-walled carbon nanotube binary colloid; S2. The prepared Mg(OH)2 / multi-walled carbon nanotube binary colloid was washed three times with distilled water and then filtered to obtain a solid powder. The obtained solid powder was placed in a vacuum drying oven and vacuum dried at 10Pa and 125°C for 12h. It was calcined in a transposed atmosphere tubular furnace, and the temperature was increased to 400°C at 20°C / min in an air atmosphere and calcined for 10min. The obtained solid was placed in a planetary ball mill, using zirconium oxide as grinding beads, and ball milled at 60rpm for 45min to obtain carbon nanotubes with surface grafted magnesium hydroxide.

[0058] The difference between Example 11 and Example 9 is that the synergist is carbon nanotubes with zinc hydroxide grafted on the surface.

[0059] The preparation method of carbon nanotubes with surface grafted zinc hydroxide is as follows: S1. 0.25 g of zinc nitrate hexahydrate is dissolved in 150 mL of distilled water, and magnetically stirred at 80 rpm / min for 0.5 h, and then 1.0 g of carbon nanotubes (industrial grade multi-walled carbon nanotubes TNIM6, diameter 20-40 nm, length 10-30 microns, purity greater than 95 wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) is added, and magnetically stirred at 80 rpm / min for 80 min, and then 3.0 wt% ammonia water is added, and the ammonia water is delivered until Al is completely precipitated and magnetically stirred at 80 rpm / min. 3.0h, let it stand for 24h to obtain Zn(OH)2 / multi-walled carbon nanotube binary colloid; S2. The prepared Zn(OH)2 / multi-walled carbon nanotube binary colloid was washed three times with distilled water and then filtered to obtain a solid powder. The solid powder was placed in a vacuum drying oven and vacuum dried at 10Pa and 95°C for 16h. It was calcined in a transposed atmosphere tubular furnace. The temperature was increased to 150°C at 10°C / min in an air atmosphere and calcined for 5min. The solid was placed in a planetary ball mill with zirconium oxide as grinding beads and ball milled at 60rpm for 45min to obtain carbon nanotubes with surface grafted zinc hydroxide.

[0060] The difference between Example 12 and Example 9 is that the synergist is the carbon nanotubes with aluminum hydroxide grafted on the surface and the zinc borate whiskers prepared in Example 9, and the mass ratio of the carbon nanotubes with aluminum hydroxide grafted on the surface to the zinc borate whiskers is 4:1.

[0061] The preparation method of zinc borate whiskers is as follows: add 50mL of 0.1mol / L Na2B4O7·10H2O solution and 1g of trioctyl phosphate into a three-necked flask and mix them evenly, place the three-necked flask in an ultrasonic cleaner for 0.5 hour, add 10mL of 2mol / L Zn(NO3)2·6H2O solution into the three-necked flask at a drop rate of 1 drop / 5s under continuous stirring, react at 70°C for 0.5 hour, add 0.1mol / L NaOH solution into the three-necked flask, adjust the pH of the solution to 8, and then continue to react at 70°C for 7 hours. After the reaction is completed, filter, wash, vacuum dry, place in a planetary ball mill for ball milling, and dry ball mill for 15 minutes at a speed of 80rpm to obtain zinc borate whiskers.

[0062] Comparative Example 1 is pure lactic acid PLA material.

[0063] The difference between Comparative Example 2 and Example 4 is that a polylactic acid 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, a purity greater than 95 wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) and 99 g of polylactic acid resin.

[0064] The performance test is as follows: 1. Evaluation of flame retardant performance: After fully drying, the pellets of the polylactic acid composite material were injection molded into test specimens (125mm*13mm*1.6mm). Based on UL (Underwriters Laboratories)-94 (standard see Table 1), a 20mm vertical burning test was carried out on the specimens to determine the flame retardant level of the specimens.

[0065] Table 1 Flame retardant test UL-94 standard

[0066] 2. Limiting oxygen index evaluation: After fully drying the pellets of the polylactic acid composite material, injection molding was performed to obtain test specimens (100mm*6.5mm*3mm). The limiting oxygen index LOI of the specimens was evaluated using an oxygen index meter.

[0067] 3. Mechanical property evaluation: After being fully dried, the pellets of the polylactic acid composite material were injection molded to obtain test specimens, and then the tensile properties were tested using a 5569 Instron universal tensile testing machine in accordance with the national standard GB / T1040.2-2006.

[0068] Table 2 is a table of test parameters of the polylactic acid composite materials in Examples 4-12 and Comparative Examples 1-2

[0069] It can be seen from Examples 4-6 and Comparative Example 1 and Table 2 that the bio-based phosphorus-nitrogen synergistic flame retardant in the present invention can give the polylactic acid composite material good flame retardant and fire safety performance at an addition amount of 1.0-1.5wt%, reaching UL-94V0.

[0070] Combining Example 5 and Example 7-8 and Table 2, it can be seen that the bio-based phosphorus-nitrogen synergistic flame retardant in Example 5 and Example 7-8 can give the polylactic acid composite material good flame retardant and fire safety performance at an addition amount of 1.0wt%, reaching UL-94 V0. At the same addition amount (1.0wt%), the flame retardant performance of the polylactic acid composite material prepared by the bio-based phosphorus-nitrogen synergistic flame retardant in Example 8 is relatively good, the R group is a benzene ring structure, and the introduction of nitrogen elements and phosphorus elements into the bio-based phosphorus-nitrogen synergistic flame retardant and the introduction of benzene ring structure at the same time 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, the polylactic acid composite material prepared by the bio-based phosphorus-nitrogen synergistic flame retardant in Example 8 is relatively poor in the elongation at break test relative to that of Example 5 and Example 7, but its tensile strength is relatively better.

[0071] Combining Example 5, Examples 9-12 and Comparative Example 2 and Table 2, it can be seen that the use of carbon nanotubes with surface grafted 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 with surface grafted metal hydroxides and the bio-based phosphorus and nitrogen synergistic flame retardant can be used synergistically to achieve a good flame retardant effect. The reason is that: the metal hydroxide in the carbon nanotubes with surface grafted metal hydroxides decomposes and absorbs heat, reduces the heat fed back to the matrix, and lowers the matrix temperature; the thermal decomposition product is water vapor, which is environmentally friendly and can dilute the oxygen concentration in the air; a dense metal oxide layer may be generated, which hinders the transfer of energy and matter; and the carbon nanotubes in the carbon nanotubes with surface grafted metal hydroxides form a continuous network structure in the matrix, and the network structure forms a continuous and complete protective layer during the combustion process, which can improve the quality of the residual carbon layer, and the residual carbon layer covers the surface of the sample, isolating and reducing the migration of volatile substances into the gas phase.

[0072] It can be seen from Example 5, Examples 9-12 and Comparative Example 2 and Table 2 that the carbon nanotubes with surface grafted metal hydroxides 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 with surface grafted metal hydroxides have improved their own polarity and better compatibility with the polylactic acid matrix, can be more dispersed in the TPU matrix, can improve the flame retardant and fireproof properties while improving the overall mechanical tensile properties of the polylactic acid composite material.

[0073] 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 a thermoplastic polyurethane elastomer TPU.

[0074] 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 mixed at a speed of 300 rpm / min for 5 minutes to obtain a premix, and then the obtained premix is ​​placed in a twin-screw extruder, melt-extruded at 150°C, wire-drawn, cooled, granulated, and finally dried to obtain pellets of the polylactic acid composite material TPU 1.0.

[0075] 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 a thermoplastic polyurethane elastomer TPU. The synergist is the carbon nanotubes with surface grafted aluminum hydroxide prepared in Example 9.

[0076] Comparative Example 3 is pure thermoplastic polyurethane elastomer TPU resin TPU 1195A.

[0077] 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, 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.

[0078] Table 3 is a table of test parameters of TPU composite materials in Examples 13-14 and Comparative Examples 3-4

[0079] Combining Example 13 and Comparative Example 3 with Table 3, it can be seen that the bio-based phosphorus-nitrogen synergistic flame retardant in the present invention can give the TPU composite material good flame retardant and fire safety performance at an addition amount of 1.0wt%, reaching UL-94 V0 level.

[0080] Combining Example 14 and Comparative Example 4 with Table 3, it can be seen that the use of carbon nanotubes with surface grafted 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 with surface grafted metal hydroxides and the bio-based phosphorus and nitrogen synergistic flame retardant can play a good flame retardant effect. In addition, the carbon nanotubes with surface grafted metal hydroxides have improved their own polarity and good compatibility with the TPU matrix, and can be more dispersed inside the TPU matrix, which can improve the flame retardant and fire safety performance while improving the overall mechanical tensile properties of the TPU composite material.

[0081] 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.

[0082] A 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 and 1.0 g of the bio-based phosphorus-nitrogen synergistic flame retardant A1 in Example 1 are evenly mixed and added to a corresponding mold, followed by curing at 80°C for 24 hours, and finally demolding to obtain a phenolic resin composite material, and test specimens are prepared by this method.

[0083] The difference between Example 16 and Example 1 is that a phenolic resin composite material prepared by 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 a phenolic resin. The synergist is the carbon nanotubes with surface grafted aluminum hydroxide prepared in Example 9.

[0084] Comparative Example 5 is pure phenolic resin (purchased from Hangmo New Materials Group Co., Ltd.).

[0085] 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 grade multi-walled carbon nanotubes TNIM6, with a tube diameter of 20-40 nm, a length of 10-30 microns, a purity greater than 95 wt%, provided by Chengdu Organic Chemistry Co., Ltd., Chinese Academy of Sciences) and 99 g of phenolic resin.

[0086] Table 4 is a table of test parameters of the phenolic resin composite materials in Examples 15-16 and Comparative Examples 5-6

[0087] Combining Example 15 and Comparative Example 5 with Table 4, it can be seen that the bio-based phosphorus-nitrogen synergistic flame retardant in the present invention can impart good flame retardant and fire safety performance to the phenolic resin composite material at an addition amount of 1.0 wt%, reaching UL-94 V0 level.

[0088] It can be seen from Example 16 and Comparative Example 6 and Table 4 that the carbon nanotubes with surface grafted metal hydroxides provided in the present invention can improve the overall flame retardant and fire safety performance of the phenolic resin composite material, that is, the carbon nanotubes with surface grafted metal hydroxides and the bio-based phosphorus-nitrogen synergistic flame retardant can be used synergistically to achieve good flame retardant and fire safety effects.

[0089] From Example 16 and Comparative Example 6 and Table 4, it can be seen that the carbon nanotubes with metal hydroxide grafted on the surface have improved their polarity and good compatibility with the phenolic resin matrix, can be more dispersed inside the phenolic resin matrix, can enhance the flame retardant and fireproof properties while improving the overall mechanical tensile properties of the phenolic resin composite material.

[0090] In summary, the present invention uses the bio-source material - ellagic acid as the main synthetic raw material, and utilizes a simple chemical reaction 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 source of synthetic raw materials is wide, and the production cost is relatively low. That is, the prepared bio-based phosphorus-nitrogen synergistic flame retardant has good flame retardancy and fire safety, and has a relatively low production cost, which is convenient for the promotion and application of phosphorus-nitrogen synergistic flame retardants.

[0091] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant, characterized in that: The bio-based phosphorus-nitrogen synergistic flame retardant is made of ellagic acid, carbon dioxide diaminophosphoryl chloride, an acid binding agent, and an organic solvent. The synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant is as follows: step 1, first adding 10 parts by weight of ellagic acid into a reaction bottle, then sequentially adding 10 to 80 parts by weight of an acid binding agent and 100 to 300 parts by weight of an organic solvent into the reaction bottle, and stirring to obtain a mixed solution; step 2, under room temperature, dropwise adding 10 to 80 parts by weight of diaminophosphoryl chloride into the mixed solution in step 1, and after the dropwise addition of diaminophosphoryl chloride is completed, continuing the reaction at room temperature for 3 to 4 hours; step 3, after the reaction is completed, filtering the reaction solution in the reaction bottle to remove the solid filter residue, and removing the organic solvent under reduced pressure to obtain the target product-bio-based phosphorus-nitrogen synergistic flame retardant.

2. The method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 1, characterized in that: The acid binding agent is an inorganic alkali metal carbonate and / or an organic base.

3. The method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 2, characterized in that: The acid binding agent is at least one of triethylamine, pyridine, 4-dimethylaminopyridine, sodium carbonate and potassium carbonate.

4. The method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 1, characterized in that: The organic solvent is at least one of N,N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphoric triamide, tetrahydrofuran, 1,4-dioxane, chloroform, N-methylpyrrolidone and xylene.

5. The method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 1, characterized in that: The diaminophosphoryl chloride structural formula 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.

6. The method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 5, characterized in that: 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.

7. The method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 5, characterized in that: The diamino phosphorus oxychloride is one of bis(N,N-dimethylamino)phosphonyl chloride, bis(diethylamino)phosphonyl chloride and bis(diphenylamino)phosphonyl chloride.

8. The method for synthesizing a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 7, characterized in that: In the structural formula of the bio-based phosphorus-nitrogen synergistic flame retardant, R is independently selected from one of methyl, ethyl and aryl.

9. A highly flame-retardant polymer composition prepared by the synthesis method of the bio-based phosphorus-nitrogen synergistic flame retardant according to any one of claims 1 to 8, characterized in that: The highly flame-retardant polymer composition 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 described in any one of claims 1-8, and 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.

10. The highly flame-retardant polymer composition prepared by the synthesis method of a bio-based phosphorus-nitrogen synergistic flame retardant according to claim 9, characterized in that: The highly flame-retardant polymer composition comprises the following raw materials in parts by mass: 0.5-1.5 parts of the bio-based phosphorus-nitrogen synergistic flame retardant described in any one of claims 1-8, 0.05-0.2 parts of a synergist, and 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; the synergist is at least one of carbon nanotubes with aluminum hydroxide grafted on the surface, carbon nanotubes with magnesium hydroxide grafted on the surface, and carbon nanotubes with zinc hydroxide grafted on the surface; or the synergist is at least one of carbon nanotubes with aluminum hydroxide grafted on the surface, carbon nanotubes with magnesium hydroxide grafted on the surface, and carbon nanotubes with zinc hydroxide grafted on the surface, combined with zinc borate whiskers to form a mixed synergist.

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