Preparation method of bio-based phytate induced ammonium polyphosphate layered interface assembled flame retardant

Abstract

The invention discloses a preparation method of a bio-based phytate induced ammonium polyphosphate layered interface assembled flame retardant. The preparation method comprises the following steps: S1, preparing an ammonium polyphosphate suspension; s2, preparing a transition metal compound solution: weighing a proper amount of a transition metal compound, and dissolving the transition metal compound in deionized water to prepare a solution A with an adaptive concentration; s3, preparing a phytic acid solution: measuring a certain volume of 70% phytic acid solution, and diluting the 70% phytic acid solution with a solvent to a predetermined concentration to obtain a solution B; s4, constructing a mixed reaction system: slowly pouring the solution A into the ammonium polyphosphate turbid liquid, and adding the solution B drop by drop under the condition of continuous violent stirring; s5, performing reflux reaction in an inert atmosphere: after the mixed system is fully uniform, performing reflux reaction in an inert gas protection atmosphere; and S6, purifying the product. According to the preparation method, low-cost renewable raw materials are adopted, the preparation process with high controllability is designed, the efficient finished product conversion efficiency can be achieved, and the fireproof protection requirements of diversified materials are met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flame-retardant material preparation, and particularly relates to a preparation method of a bio-based phytate-induced ammonium polyphosphate layered interface assembly flame retardant. BACKGROUND

[0002] In today's industrial production field, phosphorus compounds have been widely used as the main flame-retardant component for a long time, among which the phosphorus-nitrogen synergistic system composed of ammonium polyphosphate and melamine is quite representative. However, it cannot be ignored that the global phosphorus ore reserves are showing a significant depletion trend. According to the authoritative data released by the United States Geological Survey in 2023, the static reserve-production ratio of phosphorus ore has broken through the 50-year warning line, and due to the serious unevenness of its regional distribution, the risk of the supply end is further aggravated. This severe resource situation makes the traditional phosphorus flame retardant face unprecedented challenges in the sustainable application in the future.

[0003] In view of the above real difficulties, in the field, it is urgent to carry out related research work, aiming to develop a new flame-retardant system. The system needs to have high-efficiency flame-retardant performance, good environmental adaptability and resource sustainability, which has become a key technical problem to be solved in the field.

[0004] In view of the existing situation, the core components of various existing flame-retardant technologies mostly depend on non-sustainable mining of ore phosphorus resources. This dependence is contrary to the increasingly strict environmental protection policy and the long-term sustainable development strategy. Therefore, from the perspective of industry development, it is urgent to explore and develop a new flame-retardant preparation method. The method should effectively reduce the use of ore phosphorus resources in the flame-retardant field, and overcome the limitations of existing technologies. SUMMARY

[0005] The purpose of the present application is to solve the key technical bottlenecks of the prior art, such as high dependence on non-renewable mineral raw materials and environmental pollution in the production process, and to provide a preparation method of a bio-based phytate-induced ammonium polyphosphate layered interface assembly flame retardant. The method uses low-cost renewable raw materials and designs a highly controllable preparation process, which can realize high-efficiency product conversion efficiency and meet the fire protection needs of diversified materials.

[0006] To achieve the above purpose, the technical solution adopted by the present application is: a preparation method of a bio-based phytate-induced ammonium polyphosphate layered interface assembly flame retardant, comprising the following steps:

[0007] S1, preparing an ammonium polyphosphate suspension;

[0008] S2, preparation of transition metal compound solution: weigh the appropriate amount of transition metal compound and dissolve in deionized water to prepare solution A with appropriate concentration;

[0009] S3, preparation of phytic acid solution: take a certain volume of 70% phytic acid solution, dilute with solvent to the predetermined concentration to obtain solution B;

[0010] S4, construction of mixed reaction system: slowly pour solution A into ammonium polyphosphate suspension, and add solution B drop by drop under continuous vigorous stirring;

[0011] S5, inert atmosphere reflux reaction: after the above mixed system is fully uniform, carry out reflux reaction under inert gas protection atmosphere;

[0012] S6, product purification treatment.

[0013] Further, in step S1, a certain amount of ammonium polyphosphate solid is dispersed in deionized water to form a suspension with a specific concentration.

[0014] Further, in step S1, the amount of ammonium polyphosphate is controlled at 2-5 g, and the volume of deionized water is 400-800 mL.

[0015] Further, in step S2, the amount of transition metal compound is 0.2-0.5 g, and it is dissolved in 40-70 mL of deionized water.

[0016] Further, in step S2, the transition metal compound is manganese trichloride or nickel chloride hexahydrate.

[0017] Further, in step S3, the amount of 70% phytic acid solution is 0.3-0.7 g, and the total volume of solvent is 70-150 mL.

[0018] Further, in step S5, the inert gas is argon or nitrogen, and the reaction time is set to 2-4 h.

[0019] Further, in step S6, after the reflux reaction is completed, the system is cooled to room temperature, and deionized water is used for repeated washing; then drying treatment is carried out, and the target flame retardant sample is obtained after grinding and sieving.

[0020] Further, the drying conditions are vacuum oven temperature 70-90℃, drying time 8-14 h, and the mesh size after grinding is ≤500 mesh.

[0021] The flame retardant prepared by the above method can be widely used in fireproof treatment of various materials.

[0022] The beneficial effects of the application are: as a typical bio-based flame retardant monomer, phytic acid (PA) is considered as an ideal precursor for developing new bio-based flame retardants due to its high phosphorus content of up to 28wt%, excellent molecular modifiability, non-toxicity and sustainable regeneration advantages. However, due to the complexity of the compounding modification technology and the technical difficulties of the cost-benefit balance, the current phytic acid derived flame retardants are still in the research and development exploration stage, and the product types are limited. The core innovation goal of the application is to develop a new generation of phosphorus-based flame retardant based on APP-P@Mn and APP-P@Ni composite system. By skillfully constructing a composite component system of bio-based phosphorus source and mineral phosphorus source, the synergistic flame retardant effect between different phosphorus sources is fully played, and the prepared APP-P@Mn and APP-P@Ni flame retardants exhibit excellent comprehensive performance, and the flame retardant efficiency can reach the average level of current commercial application products, which provides a feasible technical path for breaking through the resource constraints of traditional phosphorus-based flame retardants

[0023] Additional aspects and advantages of the application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 SEM images of (a) APP-P@Mn, (b) APP-P@Ni, (c) APP for different magnifications;

[0025] Figure 2 Downward fire spread temperature evolution of (a) pure cellulose bed, (b) APP, (c) APP-P@Mn, (d) APP-P@Ni bed adsorbed;

[0026] Figure 3 Downward fire spread process diagram of (a) pure cellulose bed, (b) APP, (c) APP-P@Mn, (d) APP-P@Ni bed adsorbed;

[0027] Figure 4 SEM images of carbon residue containing (a) APP-P@Mn and (b) APP-P@Ni;

[0028] Figure 5 FTIR and (b) XPS curves of (a) carbon residue;

[0029] Figure 6 XPS spectra of (a) C1s and (b) P2p of carbon residue. DETAILED DESCRIPTION

[0030] The technical solutions described in the present application will be described in detail below through specific experimental examples. It should be particularly noted that the following examples only represent preferred embodiments of the present application and do not constitute any limitation on the protection scope of the present application. Based on the following examples, those skilled in the art can make reasonable modifications, adjustments or extensions without departing from the core idea and technical principles of the present application.

[0031] Example 1: Preparation of APP-P@Mn flame retardant

[0032] Initial system construction: 3 g of ammonium polyphosphate (APP) was taken and placed in a 1000 mL beaker, 600 mL of deionized water was added, and stirring was performed to form a uniform suspension;

[0033] Solution preparation: 0.4 g of manganese trichloride (MnCl3) was weighed and dissolved in 50 mL of deionized water to prepare solution A; 0.5 g of phytic acid (PA) was dissolved in 100 mL of deionized water to prepare solution B;

[0034] Complex reaction process: solution A was slowly poured into the APP suspension, high-speed mechanical stirring was started, and solution B was added dropwise at the same time;

[0035] Reflux reaction stage: after the dropwise addition was completed, the reaction system was placed in a 80°C constant temperature water bath, argon gas was introduced as a protective gas, and the reflux reaction was continued for 3 hours;

[0036] Product purification treatment: after the reaction was completed, the system was naturally cooled to room temperature, deionized water was repeatedly washed until the filtrate was clear; then it was transferred to a vacuum drying oven and dried at 80°C for 12 hours; after grinding, it was passed through a 200 mesh standard sieve, and finally the APP-P@Mn flame retardant sample was obtained.

[0037] Example 2: Preparation of APP-P@Ni flame retardant

[0038] Initial system construction: 4 g of ammonium polyphosphate (APP) was weighed and placed in a 1000 mL beaker, 600 mL of deionized water was added, and stirring was performed to form a stable suspension;

[0039] Solution preparation: 0.5 g of nickel chloride hexahydrate (NiCl2·6H2O) was weighed and dissolved in 50 mL of deionized water to prepare solution A; 0.4 g of phytic acid (PA) was dissolved in 100 mL of deionized water to prepare solution B;

[0040] Complex reaction process: solution A was slowly poured into the APP suspension, high-speed mechanical stirring was started, and solution B was added dropwise at the same time;

[0041] Reflux reaction stage: after the dropwise addition is completed, the reaction system is placed in a 80°C constant temperature water bath, argon gas is introduced as a protective gas, and the reflux reaction is continued for 2 hours;

[0042] Product purification treatment: after the reaction is completed, natural cooling to room temperature is adopted, deionized water is repeatedly washed until the filtrate is clear; then it is transferred to a vacuum drying oven and dried at 80°C for 12 hours; after grinding, it is passed through a 200 mesh standard sieve, and finally the APP-P@Ni flame retardant sample is obtained.

[0043] The following uses the cellulose material bed method (see Fire Saf. J. 153 (2025) 104382; Int. J. Biol. Macromol. 323 (2025) 147199) as a performance evaluation carrier, and systematic flame retardant efficiency research is carried out for two examples of APP-P@Mn and APP-P@Ni. Select the mainstream commercial phosphorus flame retardant ammonium polyphosphate (APP) as a control sample, and through oxygen index determination, UL-94 vertical burning test and thermal gravimetric analysis and other core indicators, the flame suppression ability of the three inhibitors is comprehensively quantified. The experiment sets low (4×10 -4 mol / g), medium (8×10 -4 mol / g), and high (1.2×10 - ³ mol / g) three adsorption concentration gradients, and deeply explores the flame retardant behavior law under different loadings.

[0044] Table 1 Oxygen index and vertical burning test results of examples and comparative examples

[0045]

[0046] As shown in Table 1, the UL-94 vertical burning test results show that the flame retardant performance of APP-P@Ni is equivalent to that of commercial APP, showing good practical application prospects; APP-P@Mn is on a par with APP at low and medium concentrations, and is only slightly lower than the control sample at high concentration, still reaching the V1 standard. The oxygen index test results further verify the above conclusion: the oxygen index of APP-P@Mn at low, medium and high concentrations reaches 95.2%, 95.9% and 97.7% of APP, respectively, indicating that it has stable flame retardant properties; APP-P@Ni performs particularly outstanding at high concentration, with an oxygen index 0.7% higher than APP, highlighting its excellent flame retardant performance at high loading, and the oxygen index at medium and low concentrations also reaches 98.6% and 97.9% of APP, respectively.

[0047] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above examples do not limit the protection scope of the present application in any form, and any technical solutions obtained by equivalent replacement or the like fall within the protection scope of the present application. The parts not involved in the present application are the same as or can be realized by using the prior art.

Claims

1. A method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant, characterized in that, Includes the following steps: S1. Prepare ammonium polyphosphate suspension; S2. Preparation of transition metal compound solution: Weigh an appropriate amount of transition metal compound and dissolve it in deionized water to prepare solution A of appropriate concentration; S3. Preparation of phytic acid solution: Measure a certain volume of 70% phytic acid solution and dilute it with solvent to the predetermined concentration to obtain solution B; S4. Construct a mixed reaction system: Slowly pour solution A into the ammonium polyphosphate suspension, and add solution B dropwise under continuous vigorous stirring. S5. Reflux reaction under inert atmosphere: After the above mixture is fully homogenized, a reflux reaction is carried out under an inert gas protective atmosphere. S6. Product purification process.

2. The method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant according to claim 1, characterized in that, In step S1, a certain amount of ammonium polyphosphate solid is dispersed in deionized water to form a suspension of a specific concentration.

3. The method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant according to claim 1 or 2, characterized in that, In step S1, the amount of ammonium polyphosphate is controlled at 2-5 g, corresponding to a deionized water volume of 400-800 mL.

4. The method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant according to claim 1, characterized in that, In step S2, the amount of transition metal compound used is 0.2–0.5 g, dissolved in 40–70 mL of deionized water.

5. A method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant according to claim 1 or 4, characterized in that, In step S2, the transition metal compound used is manganese trichloride or nickel chloride hexahydrate.

6. The method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant according to claim 1, characterized in that, In step S3, the amount of 70% phytic acid solution used is 0.3-0.7 g, and the total volume of solvent is 70-150 mL.

7. The method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant according to claim 1, characterized in that, In step S5, argon or nitrogen is selected as the inert gas, and the reaction time is set to 2-4 hours.

8. The method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant according to claim 1, characterized in that, In step S6, after the reflux reaction is completed, the system is cooled to room temperature and repeatedly washed with deionized water; then it is dried, ground and sieved to obtain the target flame retardant sample.

9. The method for preparing a bio-based phytate-induced ammonium polyphosphate layered interfacial assembly flame retardant according to claim 8, characterized in that, The drying conditions are: vacuum oven temperature 70-90℃, drying time 8-14 h, and sieve mesh size ≤500 after grinding.

10. The application of the flame retardant prepared by the method of claim 1 in fire-resistant materials.

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