Macromolecular coupling agent as well as preparation method and application thereof

Abstract

The invention relates to a macromolecular coupling agent as well as a preparation method and application thereof, belongs to the technical field of fire extinguishing products, and is used for solving at least one of the problems of low flame retardant efficiency, high cost, easiness in caking, poor solubility and the like of ammonium polyphosphate treated by an existing method. The invention relates to a preparation method of a macromolecular silane coupling agent, which comprises the following steps: adding a silane coupling agent KH550 and a silane coupling agent KH570 into a solvent to obtain a mixture; adding concentrated hydrochloric acid into the mixture, and hydrolyzing to obtain a hydrolysate; and adjusting the pH value of the hydrolysate, and reacting under stirring to obtain the macromolecular silane coupling agent. A hydrophobic chain segment in the macromolecular silane coupling agent synthesized by the method is longer than that of monomolecular silane, so that infiltration of small water drops on the surface of APP can be reduced, and the macromolecular silane coupling agent has a better hydrophobic effect; and a longer hydrophobic chain segment has an interference effect on the formation of a crystal bridge, so that the strength of the formed crystal bridge is reduced, and the caking rate of the APP powder is lower.

Description

Technical Field

[0001] This invention relates to the field of fire extinguishing product technology, and in particular to a macromolecular coupling agent, its preparation method, and its application. Background Technology

[0002] Ammonium polyphosphate (APP), as a highly efficient inorganic flame retardant, is widely used in fire extinguishing agents. However, its strong polarity and hydrophilicity lead to poor compatibility with non-polar polymer matrices, making it prone to migration and moisture absorption, which in turn degrades the mechanical properties and long-term flame-retardant stability of composite materials. Surface coating is a key approach to improving the performance of APP.

[0003] While modifying APP with common small-molecule silane coupling agents can improve compatibility to some extent, existing technologies have significant limitations. The coating layer formed after the hydrolysis and condensation of small-molecule silanes is thin and lacks density, and the interaction between its single active functional group and the APP surface is limited. In use, the barrier effect against moisture is not long-lasting, making it difficult to fundamentally solve the problems of moisture absorption and migration of APP. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a macromolecular coupling agent, its preparation method and application, to solve at least one of the problems of decreased flame retardant efficiency and easy agglomeration of ammonium polyphosphate treated by existing methods.

[0005] In a first aspect, the present invention provides a method for preparing a macromolecular silane coupling agent, comprising the following steps: (1) Place silane coupling agent KH550 and silane coupling agent KH570 in a solvent, stir and mix evenly to obtain a mixture; (2) The pH of the mixture is lowered, and the mixture is stirred at room temperature to carry out hydrolysis to obtain the hydrolysis product; (3) Increase the pH of the hydrolysis product, raise the temperature, react with stirring, cool down, purify and wash to obtain the macromolecular silane coupling agent (denoted as KH-Si).

[0006] Furthermore, in step (1), the molar ratio of the silane coupling agent KH550 and the silane coupling agent KH570 is 1:2-2:1.

[0007] Furthermore, in step (1), the stirring rate is 200-400 r / min and the stirring time is 5-20 min.

[0008] Furthermore, in step (2), the pH value is reduced to 4-6, and the hydrolysis time is 2-4 hours.

[0009] Furthermore, in step (2), the stirring rate is 200-400 r / min and the stirring time is 2-4 h.

[0010] Furthermore, in step (3), the pH value is increased by 8~10.

[0011] Furthermore, in step (3), the temperature is raised to 50-60℃, and the stirring rate remains unchanged to continue the reaction for 0.5-2h.

[0012] Secondly, the present invention provides a macromolecular silane coupling agent prepared by the above method, wherein the structural formula of the macromolecular silane coupling agent is as follows: ; Where n is the number of repeating units, and the average value of n is 1 to 3.

[0013] Thirdly, the present invention provides an application of the above-mentioned macromolecular silane coupling agent in the modification of ammonium polyphosphate.

[0014] Fourthly, the present invention provides an ultrafine dry powder fire extinguishing agent, comprising ammonium polyphosphate modified with the above-mentioned macromolecular silane coupling agent.

[0015] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: (1) The macromolecular silane coupling agent of the present invention is obtained by condensation of silane coupling agent KH550 and silane coupling agent KH570. The hydrophobic segments in the macromolecular silane coupling agent synthesized by the method of the present invention are longer than those in monomolecular silane, which can reduce the wetting of small water droplets on the APP surface and have better hydrophobic effect; and the longer hydrophobic segments interfere with the formation of crystal bridges, reduce the strength of the formed crystal bridges, and make the agglomeration of APP powder easier to break. The combination of macromolecular silane coupling agent and APP powder is limited to the combination site between the two, and the dispersion in APP powder is more uniform, which improves the solubility. (2) In the synthesis of macromolecular silanes in this invention, it is necessary to control the pH of each reaction step to prevent the reaction rate from being too fast and to reduce the generation of by-products; (3) In the application of the macromolecular silane coupling agent of the present invention, modified ammonium polyphosphate is used as the main raw material in the fire extinguishing agent. Since the modified ammonium polyphosphate has a high solubility and a low agglomeration rate, the fire extinguishing agent prepared has water-repellent and moisture-proof properties, strong anti-agglomeration ability, and extends the product's storage period.

[0016] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0017] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Figure 1 NMR spectrum of the macromolecular silane coupling agent prepared in Example 1 of this invention; Figure 2 The infrared spectrum of the macromolecular silane coupling agent prepared in Example 2 of this invention; Figure 3 This is the XPS spectrum of ammonium polyphosphate before modification in Example 3 of the present invention; Figure 4 This is the XPS spectrum of the modified ammonium polyphosphate in Example 3 of the present invention; Figure 5 This is a physical image of the agglomeration rate test in this invention. Detailed Implementation

[0018] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0019] The chemical formulas of the silane coupling agents KH550 and KH570 used in this invention are shown in Table 1. Unless otherwise specified, all raw materials used in this invention are commercially available products or prepared using existing methods.

[0020] Table 1

[0021] A specific embodiment of the present invention discloses a method for preparing a macromolecular silane coupling agent, comprising the following steps: (1) Place silane coupling agent KH550 and silane coupling agent KH570 in a solvent, stir and mix evenly to obtain a mixture; (2) The pH of the mixture is lowered, and the mixture is stirred at room temperature to carry out hydrolysis to obtain the hydrolysis product; (3) Increase the pH of the hydrolysis product, raise the temperature, react with stirring, cool down, purify and wash to obtain the macromolecular silane coupling agent (denoted as KH-Si).

[0022] It should be noted that the reaction equations for the hydrolysis of silane coupling agent KH550 and silane coupling agent KH570 in step (2) of this invention are shown in reaction one and reaction two: ; The equation for the reaction in step (3) is shown in reaction three: ; Specifically, in step (1), the molar ratio of the silane coupling agent KH550 and the silane coupling agent KH570 is 1:2-2:1, for example, 1:2, 1:1.8, 1:1.6, 1:1.4, 1:1.2, 1:1, 1:0.8, 1:0.6, 1:0.5, and the mass concentration of the silane coupling agent KH550 in the mixture is 1-25%, for example, 1%, 3%, 5%, 7%, 9%, 11%, 13%, 15%, 17%, 19%, 21%, 23%, 25%.

[0023] Specifically, in step (1), the solvent is ethanol or methanol, which are miscible with KH550 and KH570.

[0024] Specifically, in step (1), the stirring rate is 200-400 r / min, for example, 200 r / min, 220 r / min, 240 r / min, 260 r / min, 280 r / min, 300 r / min, 320 r / min, 340 r / min, 360 r / min, 380 r / min, 400 r / min, and the stirring time is 5-20 min, for example, 5 min, 7 min, 9 min, 11 min, 13 min, 15 min, 17 min, 19 min, 20 min.

[0025] Specifically, in step (2), the pH value is reduced to 4~6, for example, 4, 4.2, 4.4, 4.6, 4.8, 5.0, 5.2, 5.4, 5.6, 5.8, 6, and the hydrolysis time is 2-4h, for example, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3.0h, 3.2h, 3.4h, 3.6h, 3.8h, 4h.

[0026] It should be noted that a pH value below 4 will cause the hydrolysis rate to be too fast, generating byproducts; a pH value above 6 will cause the hydrolysis rate to be too slow.

[0027] Specifically, in step (2), the stirring rate is 200-400 r / min, for example, 200 r / min, 220 r / min, 240 r / min, 260 r / min, 280 r / min, 300 r / min, 320 r / min, 340 r / min, 360 r / min, 380 r / min, 400 r / min, and the stirring time is 2-4 h, for example, 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3.0 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h.

[0028] Specifically, in step (3), the pH value is increased by 8~10, for example, 8, 8.2, 8.4, 8.6, 8.8, 9, 9.2, 9.4, 9.6, 9.8, 10.

[0029] It should be noted that a pH value greater than 10 will cause explosive polymerization and produce byproducts; a pH value less than 8 will result in a slow condensation reaction rate, or even no reaction at all.

[0030] It should be noted that in this invention, concentrated hydrochloric acid, glacial acetic acid, formic acid, and other acids that are miscible with the solvent and readily volatile are used to lower the pH; triethylamine, ammonia, and other bases that are miscible with the solvent and readily volatile are used to raise the pH.

[0031] Specifically, in step (3), the temperature is raised to 50-60℃, for example, 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃, 60℃, and the stirring rate remains unchanged to continue the reaction for 0.5-2h, for example, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h.

[0032] Specifically, in step (3), the temperature is lowered to room temperature.

[0033] The structural formula of the macromolecular coupling agent prepared by the above method is as follows: ; Where n is the number of repeating units (degree of aggregation), and the average value of n is 1 to 3, for example, 1, 1.2, 1.4, 1.6, 1.8, 2.0, 2.2, 2.4, 2.6, 2.8, 3.

[0034] Another specific embodiment of the present invention discloses the application of the above-mentioned macromolecular silane coupling agent in the modification of ammonium polyphosphate, wherein the ammonium polyphosphate modified by the macromolecular silane coupling agent is used in fire extinguishing agent raw materials.

[0035] During storage, the gaps formed between APP particles during contact create capillaries that absorb moisture from the air. This moisture, accumulating on the particle surface, dissolves the APP, forming a saturated solution. As the temperature rises, the concentration of the saturated solution increases; as the temperature drops, the solution becomes supersaturated, causing crystals to precipitate. Alternatively, as the moisture evaporates, the solution becomes supersaturated again, also leading to crystal precipitation. Over time, this process repeats itself, and these crystals combine to form crystal bridges, binding the particles together and gradually forming large clumps.

[0036] After coating APP with the macromolecular silane coupling agent of the present invention, not only is the agglomeration rate reduced, but the solubility remains unaffected. This is because the hydrophobic segments in the macromolecular silane coupling agent synthesized in this invention are longer than those in monomolecular silane, which reduces the wetting of small water droplets on the APP surface and provides better hydrophobicity. Furthermore, the longer hydrophobic segments interfere with the formation of crystal bridges, reducing the strength of the formed crystal bridges and making it easier to break up APP powder agglomerates. The improved solubility is due to the fact that the bonding between the macromolecular silane coupling agent and the APP powder is limited to the bonding sites, resulting in more uniform dispersion within the APP powder.

[0037] Another specific embodiment of the present invention discloses a method for preparing modified ammonium polyphosphate, comprising: dispersing ammonium polyphosphate in anhydrous ethanol by stirring, adding the above-mentioned macromolecular silane coupling agent, stirring to carry out the reaction, filtering, washing, and drying to obtain the modified ammonium polyphosphate (denoted as KH-Si@APP).

[0038] Specifically, the mass fraction of the ammonium polyphosphate in anhydrous ethanol is 5-50%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, and 50%.

[0039] Specifically, the mass ratio of the ammonium polyphosphate to the macromolecular silane coupling agent is 100:0.5~2.5, for example, 100:0.5, 100:0.7, 100:0.9, 100:1.1, 100:1.3, 100:1.5, 100:1.7, 100:1.9, 100:2.1, 100:2.3, 100:2.5. Preferably, the mass ratio is 100:0.5~1.5.

[0040] Specifically, the stirring rate is 400~600 r / min, for example, 400 r / min, 420 r / min, 440 r / min, 460 r / min, 480 r / min, 500 r / min, 520 r / min, 540 r / min, 560 r / min, 580 r / min, 600 r / min; the stirring reaction temperature is 25~55℃, for example, 25℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃; and the stirring reaction time is 3-6h, for example, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h.

[0041] Preferably, the washing is an ethanol wash at least three times.

[0042] Preferably, the drying temperature is 40-80℃, for example, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, and the drying time is 4-12h, for example, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h.

[0043] Another specific embodiment of the present invention discloses a modified ammonium polyphosphate prepared by the above method, wherein the modified ammonium polyphosphate is composed of an ammonium polyphosphate core and a macromolecular silane coupling agent coated on the surface of the ammonium polyphosphate.

[0044] Another specific embodiment of the present invention discloses the application of the above-mentioned modified ammonium polyphosphate in ultrafine dry powder fire extinguishing agents.

[0045] Another specific embodiment of the present invention discloses an ultrafine dry powder fire extinguishing agent, wherein the raw materials of the fire extinguishing agent, by weight, include: 75-95 parts of modified ammonium polyphosphate (e.g., 75 parts, 77 parts, 79 parts, 81 parts, 83 parts, 85 parts, 87 parts, 89 parts, 91 parts, 93 parts, 95 parts) and 0.5-5.0 parts of mica powder (e.g., 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3 parts). 5 parts, 4 parts, 4.5 parts, 5 parts), perlite 0.5~5.0 parts (e.g. 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts), silicone oil 1.5~6.0 parts (e.g. 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, 5.0 parts, 5.5 parts, 6.0 parts), magnesium stearate 1.0~2. 0 parts (e.g., 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 parts), 2.3-6.3 parts fumed silica (e.g., 2.3, 2.5, 2.7, 2.9, 3.1, 3.3, 3.5, 3.7, 3.9, 4.1, 4.3, 4.5, 4.7, 4... 0.9 parts, 5.1 parts, 5.3 parts, 5.5 parts, 5.7 parts, 5.9 parts, 6.1 parts, 6.3 parts), sodium dodecylbenzenesulfonate 0.5 to 2.0 parts (e.g., 0.5 parts, 0.7 parts, 0.9 parts, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, 1.9 parts, 2 parts), and activated clay 0.1 to 0.5 parts (e.g., 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts).

[0046] Preferably, the raw materials of the fire extinguishing agent include: 85-92 parts of modified ammonium polyphosphate, 0.5-1.2 parts of mica powder, 0.5-1.8 parts of perlite, 2.0-4.0 parts of silicone oil, 1.0-1.8 parts of magnesium stearate, 3.0-5.0 parts of fumed silica, 0.8-1.3 parts of sodium dodecylbenzenesulfonate, and 0.1-0.3 parts of activated clay.

[0047] Compared with existing technologies, the fire extinguishing agent of this invention uses modified ammonium polyphosphate as the main raw material. Modified ammonium polyphosphate has high solubility and low agglomeration rate. It also has good compatibility with silicone oil, making it easier for silicone oil to adsorb onto the surface of the ammonium polyphosphate. Both the coating layer on the surface of the modified ammonium polyphosphate and the silicone oil have moisture-proof properties. Furthermore, the modified ammonium polyphosphate, through coating with a macromolecular silane coupling agent and adsorption with fumed silica, reduces the moisture content and hygroscopicity of the particles, resulting in water-repellent and moisture-proof properties, strong anti-agglomeration ability, and extended product shelf life.

[0048] Another specific embodiment of the present invention discloses a method for preparing the above-mentioned fire extinguishing agent, comprising the following steps: (a) Modified ammonium polyphosphate, sodium dodecylbenzenesulfonate, mica powder and perlite are ground to obtain the first product; (b) Stir silicone oil, magnesium stearate and fumed silica in ethanol until homogeneous, add water and activated clay and stir to disperse to obtain the second product; (c) The second product is added to the first product under stirring, ground, and dried to obtain the fire extinguishing agent.

[0049] The preparation method of the fire extinguishing agent of the present invention first grinds modified ammonium polyphosphate, sodium dodecylbenzenesulfonate, mica powder and perlite, and then adds a second product for grinding. This achieves full contact and stepwise fine dispersion of each component under dry and wet conditions. The method of the present invention makes the modified ammonium polyphosphate particles smaller and the dispersion effect better, which can effectively improve the fire extinguishing effect of the fire extinguishing agent.

[0050] The method for preparing the fire extinguishing agent of the present invention is simple to operate, easy to control, has low production cost, and is suitable for industrial production.

[0051] Specifically, in step (a), the grinding is carried out in a mechanical pulverizer with a grinding speed of 300~500 r / min, for example, 300 r / min, 320 r / min, 340 r / min, 360 r / min, 380 r / min, 400 r / min, 420 r / min, 440 r / min, 460 r / min, 480 r / min, 500 r / min, and a grinding time of 0.5-4 h, for example, 0.5 h, 1.0 h, 1.5 h, 2.0 h, 2.5 h, 3 h, 3.5 h, 4 h.

[0052] Specifically, in step (b), the total mass ratio of silicone oil, magnesium stearate, and fumed silica to ethanol is 1:15-1:25, for example, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24, 1:25.

[0053] Specifically, the volume ratio of water to ethanol is 1:10 to 1:5, for example, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5.

[0054] Specifically, in step (b), the stirring and dispersion rate is 600-800 r / min, for example, 600 r / min, 620 r / min, 640 r / min, 660 r / min, 680 r / min, 700 r / min, 720 r / min, 740 r / min, 760 r / min, 780 r / min, 800 r / min, and the stirring temperature is 55-65 ℃, for example, 55 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃, 60 ℃, 61 ℃, 62 ℃, 63 ℃, 64 ℃, 65 ℃.

[0055] It should be noted that too low a stirring rate or too low a stirring temperature will result in low sample dispersion; too high a stirring rate will cause rotor instability, and too high a stirring temperature will cause sample decomposition.

[0056] Specifically, in step (c), the stirring rate is 600~900 r / min, for example, 600 r / min, 620 r / min, 640 r / min, 660 r / min, 680 r / min, 700 r / min, 720 r / min, 740 r / min, 760 r / min, 780 r / min, 800 r / min, 820 r / min, 840 r / min, 860 r / min, 880 r / min, 900 r / min, and the stirring time is 20~30 min, for example, 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min.

[0057] It should be noted that too low a stirring rate or too short a stirring time will result in low sample dispersion; too high a stirring rate will cause rotor instability and excessive stirring time, wasting processing time.

[0058] Specifically, in step (c), the grinding speed is 400~800 r / min, for example, 400 r / min, 420 r / min, 440 r / min, 460 r / min, 480 r / min, 500 r / min, 520 r / min, 540 r / min, 560 r / min, 580 r / min, 600 r / min, 620 r / min, 640 r / min, 660 r / min, 680 r / min, 700 r / min, 720 r / min, 740 r / min, 760 r / min, 780 r / min, 800 r / min.

[0059] It should be noted that if the grinding speed is too low, the sample particle size will not meet the required standard; if the grinding speed is too high, the grinding mill temperature will be too high, leading to sample decomposition.

[0060] Specifically, in step (c), the drying temperature is 50~80℃, for example, 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, 62℃, 64℃, 66℃, 68℃, 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, and the drying time is 30~50min, for example, 30min, 32min, 34min, 36min, 38min, 40min, 42min, 44min, 46min, 48min, 50min, until the moisture content is <0.15%.

[0061] This invention introduces macromolecular silane coupling agents into the field of APP surface coating. Compared with traditional small-molecule silanes, macromolecular silanes have significantly higher molecular weights and longer molecular chains, and typically contain multiple active reaction sites. This structural characteristic allows them to form stronger and more stable chemical bonds on the APP surface through multi-point anchoring. Simultaneously, their long molecular chain structure facilitates the construction of a more cross-linked, denser, and thicker organic hydrophobic protective layer. This coating layer effectively blocks the erosion of environmental moisture, significantly reducing the hygroscopic rate of APP; and fundamentally inhibits APP migration through enhanced steric hindrance and excellent interfacial entanglement with the polymer matrix. Therefore, the development of macromolecular silane coupling agents specifically for APP coating is of crucial industrial significance for the preparation of high-performance, long-life flame retardants.

[0062] The technical solution of the present invention will be further explained below with reference to specific embodiments.

[0063] Preparation Example 1 The structural formula of a macromolecular silane coupling agent prepared in this example is as follows: , where n has an average value of 2.

[0064] The preparation method of the macromolecular coupling agent in this example includes the following steps: (1) Mix silane coupling agent KH550 and silane coupling agent KH570 in ethanol at a stirring rate of 200 r / min for 10 min until homogeneous to obtain a mixture; The molar ratio of the silane coupling agent KH550 to the silane coupling agent KH570 is 1:1, and the mass concentration of the silane coupling agent KH550 is 4.42%.

[0065] (2) Add concentrated hydrochloric acid to the mixture, adjust the pH value to between 4 and 5, stir at room temperature at a stirring rate of 200 r / min for 2 h, and perform hydrolysis to obtain hydrolysis products; (3) Add triethylamine to the hydrolysis product, adjust the pH value to between 8 and 9, heat to 60°C, continue to maintain the stirring rate at 200 r / min, and react for 1 hour under stirring. Cool down to room temperature and terminate the reaction. Drop the reaction liquid into an open container and allow ethanol, water, hydrogen chloride, triethylamine and other substances to fully evaporate at room temperature to obtain a gel-like substance. Wash with ethanol to remove excess small molecules. Repeat the above evaporation operation to obtain a gel-like substance, namely the macromolecular silane coupling agent (denoted as KH-Si).

[0066] The macromolecular silane coupling agent prepared in this preparation example was subjected to NMR analysis, and the NMR spectrum is shown below. Figure 1 As shown. From Figure 1 As can be seen, the peaks at 6.00 ppm and 5.66 ppm indicate the presence of two H atoms on the CH2=C- group. 1 The peak at 1.86 ppm indicates the presence of the H atom of the methyl group on the CH2=C(CH3)-. 1 Peak; H of the terminal methylene group of KH550 is observed at 2.79 ppm. 1 The peak at 0.67 ppm shows the H atom of the first methylene group of silylpropyl-Si-CH2-. 1 The peak at 1.69 ppm indicates the H atom of the second methylene group of silylpropyl-Si-CH2-CH2-. 1 The peak at 1.86 ppm indicates the H+ of the primary amine -NH2. 1 Peak. No H-representation of methoxy groups was found in KH570 at 3.5–3.6 ppm. 1 The peak was not found at 307-308 ppm for KH550 regarding the ethoxy group. 1 The peak indicates that KH550 and KH570 have completely reacted, with no residual small molecules. NMR spectroscopy confirms that KH550 and KH570 form a macromolecular silane coupling agent.

[0067] The macromolecular silane coupling agent prepared in this example was subjected to infrared analysis, and the infrared spectrum is shown below. Figure 2 As shown. Figure 2 The infrared spectrum of KH-Si is shown. The peak related to the KH550 molecule is at 3407 cm⁻¹. -1 The stretching vibration peak corresponding to the primary amine -NH2 is 1102 cm⁻¹. -1 Corresponding to the stretching vibration peak of the silicon-carbon bond (Si-C); KH570 molecular-related peak: 1102 cm⁻¹ -1 The corresponding stretching vibration peak of the silicon-carbon bond (Si-C) is 1714 cm⁻¹. -1 The corresponding stretching vibration peak for the carbon-oxygen double bond C=O is 1193 cm⁻¹. -1 The corresponding stretching vibration peak for the carbon-oxygen bond (CO) is 1634 cm⁻¹. -1 This corresponds to the stretching vibration peak of the carbon-carbon double bond C=C. 1029 cm⁻¹ -1 The stretching vibration peak corresponding to the Si-O-Si bond of silicon-carbon indicates that the silane coupling agent has been successfully cross-linked, generating a macromolecular silane coupling agent.

[0068] Preparation Example 2 The structural formula of a macromolecular silane coupling agent prepared in this example is as follows: , where n has an average value of 1.8.

[0069] The preparation method of the macromolecular coupling agent in this example includes the following steps: (1) Mix silane coupling agent KH550 and silane coupling agent KH570 in ethanol at a stirring rate of 300 r / min for 20 min until homogeneous to obtain a mixture; The molar ratio of the silane coupling agent KH550 to the silane coupling agent KH570 is 2:1, and the mass concentration of the silane coupling agent KH550 is 4.42%.

[0070] (2) Add glacial acetic acid to the mixture, adjust the pH value to between 4 and 5, stir at room temperature at a stirring rate of 300 r / min for 3 h, and carry out hydrolysis to obtain hydrolysis products; (3) Add ammonia to the hydrolysis product, adjust the pH value to between 8 and 9, heat to 50°C, continue to maintain the stirring rate at 300 r / min, and react for 0.5 h under stirring. Cool down to room temperature and terminate the reaction. Drop the reaction liquid into an open container and allow methanol, water, acetic acid, ammonia and other substances to fully evaporate at room temperature to obtain a gel-like substance. Wash with ethanol to remove excess small molecules. Repeat the above evaporation operation to obtain a gel-like substance, namely the macromolecular silane coupling agent (denoted as KH-Si).

[0071] The macromolecular silane coupling agent prepared in this preparation example was subjected to NMR analysis, and the results were consistent with those of Preparation Example 1. Due to space limitations, they will not be listed one by one.

[0072] Preparation Example 3 The structural formula of a macromolecular silane coupling agent prepared in this example is as follows: , where n has an average value of 2.4.

[0073] The preparation method of the macromolecular coupling agent in this example includes the following steps: (1) Mix silane coupling agent KH550 and silane coupling agent KH570 in ethanol at a stirring rate of 400 r / min for 5 min until homogeneous to obtain a mixture; The molar ratio of the silane coupling agent KH550 to the silane coupling agent KH570 is 1:2, and the mass concentration of the silane coupling agent KH550 is 11.05%.

[0074] (2) Add formic acid to the mixture, adjust the pH value to between 4 and 5, stir at room temperature at a stirring rate of 400 r / min for 4 h, and perform hydrolysis to obtain the hydrolysis product; (3) Add triethylamine to the hydrolysis product, adjust the pH value to between 8 and 9, heat to 55°C, continue to maintain the stirring rate at 400 r / min, and react for 2 hours under stirring. Cool down to room temperature and terminate the reaction. Drop the reaction liquid into an open container and allow ethanol, water, formic acid, triethylamine and other substances to fully evaporate at room temperature to obtain a gel-like substance. Wash with ethanol to remove excess small molecules. Repeat the above evaporation operation to obtain a gel-like substance, namely the macromolecular silane coupling agent (denoted as KH-Si).

[0075] The macromolecular silane coupling agent prepared in this preparation example was subjected to NMR analysis, and the results were consistent with those of Preparation Example 1. Due to space limitations, they will not be listed one by one.

[0076] The degree of polymerization of ammonium polyphosphate (APP) in the following examples is explained using 5-20 as an example, but it is not limited to this. The industrial-grade ammonium polyphosphate with an effective content of 99% is manufactured by Shandong Benniu Chemical Co., Ltd. In the following application examples, 1 part is 1g as an example for explanation.

[0077] Example 1 The preparation method of modified ammonium polyphosphate in this embodiment includes the following steps: Ammonium polyphosphate was dispersed in anhydrous ethanol by stirring, wherein the mass fraction of ammonium polyphosphate in anhydrous ethanol was 20%, and the macromolecular silane coupling agent prepared in Preparation Example 1 was added, wherein the mass ratio of ammonium polyphosphate to macromolecular silane coupling agent was 100:1. The mixture was stirred at 40°C and a stirring rate of 500 r / min for 4 h, filtered, washed three times with ethanol, and dried at 60°C for 6 h to obtain the modified ammonium polyphosphate (denoted as KH-Si@APP).

[0078] XPS analysis was performed on the ammonium polyphosphate before and after modification in this embodiment. The results were basically the same as those in Example 1. Due to space limitations, they will not be listed one by one.

[0079] Example 2 The preparation method of modified ammonium polyphosphate in this embodiment includes the following steps: Ammonium polyphosphate was dispersed in anhydrous ethanol by stirring, wherein the mass fraction of ammonium polyphosphate in anhydrous ethanol was 50%. The macromolecular silane coupling agent prepared in Preparation Example 1 was added, wherein the mass ratio of ammonium polyphosphate to macromolecular silane coupling agent was 100:0.5. The mixture was stirred at 40°C and a stirring rate of 400 r / min for 4.5 h. After filtration, the mixture was washed three times with ethanol and dried at 60°C for 12 h to obtain the modified ammonium polyphosphate (denoted as KH-Si@APP).

[0080] XPS analysis was performed on the ammonium polyphosphate before and after modification in this embodiment. The results were basically the same as those in Example 1. Due to space limitations, they will not be listed one by one.

[0081] Example 3 The preparation method of modified ammonium polyphosphate in this embodiment includes the following steps: Ammonium polyphosphate was dispersed in anhydrous ethanol by stirring, wherein the mass fraction of the ammonium polyphosphate in anhydrous ethanol was 5%. The macromolecular silane coupling agent prepared in Preparation Example 1 was added, wherein the mass ratio of the ammonium polyphosphate to the macromolecular silane coupling agent was 100:1.5. The mixture was stirred at 55°C and a stirring rate of 600 r / min for 3 h. After filtration, the mixture was washed three times with ethanol and dried at 60°C for 4 h to obtain the modified ammonium polyphosphate (denoted as KH-Si@APP).

[0082] XPS analysis was performed on the surface of the ammonium polyphosphate before and after modification in this embodiment, such as... Figure 3 and 4 As shown.

[0083] according to Figure 3 The XPS spectrum of ammonium polyphosphate (APP) before modification shows that there is no Si2p peak at the binding energy of 103 eV, while... Figure 4In the XPS spectrum of KH-Si@APP, a Si 2p peak at a binding energy of 103 eV is observed. Elemental composition analysis shows that Si accounts for 1.71% of APP, while in KH-Si@APP it accounts for 11.91%, further demonstrating the successful encapsulation of APP by the macromolecular silane coupling agent.

[0084] Example 4 The preparation method of modified ammonium polyphosphate in this embodiment includes the following steps: Ammonium polyphosphate was dispersed in anhydrous ethanol by stirring, wherein the mass fraction of ammonium polyphosphate in anhydrous ethanol was 20%, and the macromolecular silane coupling agent prepared in Preparation Example 1 was added, wherein the mass ratio of ammonium polyphosphate to the macromolecular silane coupling agent was 100:2.5. The mixture was stirred at 55°C and a stirring rate of 600 r / min for 4 h, filtered, washed three times with ethanol, and dried at 60°C for 6 h to obtain the modified ammonium polyphosphate (denoted as KH-Si@APP).

[0085] XPS analysis was performed on the ammonium polyphosphate before and after modification in this embodiment. The results were basically the same as those in Example 3. Due to space limitations, they will not be listed one by one.

[0086] Example 5 The preparation method of modified ammonium polyphosphate in this embodiment includes the following steps: Ammonium polyphosphate was dispersed in anhydrous ethanol by stirring, wherein the mass fraction of the ammonium polyphosphate in anhydrous ethanol was 50%. The macromolecular silane coupling agent prepared in Preparation Example 2 was added, wherein the mass ratio of the ammonium polyphosphate to the macromolecular silane coupling agent was 100:1. The mixture was stirred at 40°C and a stirring rate of 400 r / min for 4.5 h. After filtration, the mixture was washed three times with ethanol and dried at 60°C for 12 h to obtain the modified ammonium polyphosphate (denoted as KH-Si@APP).

[0087] XPS analysis was performed on the ammonium polyphosphate before and after modification in this embodiment. The results were basically the same as those in Example 3. Due to space limitations, they will not be listed one by one.

[0088] Example 6 The preparation method of modified ammonium polyphosphate in this embodiment includes the following steps: Ammonium polyphosphate was dispersed in anhydrous ethanol by stirring, wherein the mass fraction of the ammonium polyphosphate in anhydrous ethanol was 50%, and the macromolecular silane coupling agent prepared in Preparation Example 3 was added, wherein the mass ratio of the ammonium polyphosphate to the macromolecular silane coupling agent was 100:1. The mixture was stirred at 40°C and a stirring rate of 400 r / min for 4.5 h, filtered, washed three times with ethanol, and dried at 60°C for 12 h to obtain the modified ammonium polyphosphate (denoted as KH-Si@APP).

[0089] XPS analysis was performed on the ammonium polyphosphate before and after modification in this embodiment. The results were basically the same as those in Example 3. Due to space limitations, they will not be listed one by one.

[0090] Example 7 The preparation method of modified ammonium polyphosphate in this embodiment includes the following steps: Ammonium polyphosphate was dispersed in anhydrous ethanol by stirring, wherein the mass fraction of ammonium polyphosphate in anhydrous ethanol was 50%. The macromolecular silane coupling agent prepared in Preparation Example 3 was added, wherein the mass ratio of ammonium polyphosphate to macromolecular silane coupling agent was 100:1.5. The mixture was stirred at 40°C and a stirring rate of 400 r / min for 4.5 h. After filtration, the mixture was washed three times with ethanol and dried at 60°C for 12 h to obtain the modified ammonium polyphosphate (denoted as KH-Si@APP).

[0091] XPS analysis was performed on the ammonium polyphosphate before and after modification in this embodiment. The results were basically the same as those in Example 3. Due to space limitations, they will not be listed one by one.

[0092] Application Example 1 This application example of an ultrafine dry powder fire extinguishing agent comprises, by weight, 89 parts of modified ammonium polyphosphate prepared in Example 3, 1.0 part of mica powder, 0.5 parts of perlite, 3.0 parts of silicone oil, 1.0 part of magnesium stearate, 4.3 parts of fumed silica, 1.0 part of sodium dodecylbenzenesulfonate, and 0.2 parts of activated clay.

[0093] The preparation method of the ultrafine dry powder fire extinguishing agent in this application example includes the following steps: (a) Modified ammonium polyphosphate, sodium dodecylbenzenesulfonate, mica powder and perlite were ground in a mechanical pulverizer at a speed of 500 r / min for 1 h to obtain the first product; (b) Silicone oil, magnesium stearate and fumed silica are stirred evenly in ethanol, with the total mass ratio of silicone oil, magnesium stearate and fumed silica to ethanol being 1:20. Water and activated clay are added and stirred to disperse the mixture, with the volume ratio of water to ethanol being 1:8. The stirring and dispersion rate is 700 r / min and the stirring temperature is 60 °C to obtain the second product. (c) The second product is added to the first product under stirring at a stirring rate of 800 rpm for 30 min. The mixture is then ground at a grinding speed of 800 r / min and dried at a temperature of 70°C for 40 min to obtain the fire extinguishing agent.

[0094] Application Example 2 This application example of an ultrafine dry powder fire extinguishing agent comprises, by weight, 89 parts of modified ammonium polyphosphate prepared in Example 2, 1.0 part of mica powder, 0.5 parts of perlite, 3.0 parts of silicone oil, 1.0 part of magnesium stearate, 4.3 parts of fumed silica, 1.0 part of sodium dodecylbenzenesulfonate, and 0.2 parts of activated clay.

[0095] The preparation method of the ultrafine dry powder fire extinguishing agent in this application example includes the following steps: (a) Modified ammonium polyphosphate, sodium dodecylbenzenesulfonate, mica powder and perlite were ground in a mechanical pulverizer at a speed of 300 r / min for 1.5 h to obtain the first product; (b) Silicone oil, magnesium stearate and fumed silica are stirred evenly in ethanol, with the total mass of silicone oil, magnesium stearate and fumed silica to the mass-volume ratio of ethanol being 1:15. Water and activated clay are added and stirred to disperse, with the volume ratio of water to ethanol being 1:5. The stirring and dispersion rate is 600 r / min and the stirring temperature is 55°C to obtain the second product. (c) The second product is added to the first product under stirring at a stirring rate of 600 rpm for 25 min, then ground at a grinding speed of 400 r / min and dried at 50°C for 50 min to obtain the fire extinguishing agent.

[0096] Application Example 3 This application example provides an ultrafine dry powder fire extinguishing agent. By weight, the raw materials of the fire extinguishing agent include: 89 parts of modified ammonium polyphosphate prepared in Example 4, 1.0 part of mica powder, 0.5 parts of perlite, 3.0 parts of silicone oil, 1.0 part of magnesium stearate, 4.3 parts of fumed silica, 1.0 part of sodium dodecylbenzenesulfonate, and 0.2 parts of activated clay. The preparation method of this application example's ultrafine dry powder fire extinguishing agent includes the following steps: (a) Modified ammonium polyphosphate, sodium dodecylbenzenesulfonate, mica powder and perlite were ground in a mechanical pulverizer at a speed of 400 r / min for 4 h to obtain the first product; (b) Silicone oil, magnesium stearate and fumed silica are stirred evenly in ethanol, with the total mass of silicone oil, magnesium stearate and fumed silica to the mass-volume ratio of ethanol being 1:25. Water and activated clay are added and stirred to disperse, with the volume ratio of water to ethanol being 1:10. The stirring and dispersion rate is 800 r / min and the stirring temperature is 65 ℃ to obtain the second product. (c) The second product is added to the first product under stirring at a stirring rate of 900 rpm for 20 min. The mixture is then ground at a grinding speed of 600 r / min and dried at 80°C for 30 min to obtain the fire extinguishing agent.

[0097] Application Example 4 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the sodium dodecylbenzenesulfonate in the fire extinguishing agent raw material is 2.0 parts.

[0098] Application Example 5 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the sodium dodecylbenzenesulfonate in the fire extinguishing agent raw material is 0.5 parts.

[0099] Application Example 6 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the amount of silicone oil in the fire extinguishing agent raw material is 6.0 parts.

[0100] Application Example 7 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the amount of silicone oil in the fire extinguishing agent raw material is 1.5 parts.

[0101] Application Example 8 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the fumed silica in the fire extinguishing agent raw material is 6.3 parts.

[0102] Application Example 9 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the fumed silica in the fire extinguishing agent raw material is 2.3 parts.

[0103] Application Example 10 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the modified ammonium polyphosphate is 75 parts, mica powder is 3.0 parts, perlite is 3.0 parts, magnesium stearate is 1.5 parts, and activated clay is 0.1 parts.

[0104] Application Example 11 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the modified ammonium polyphosphate is 95 parts, mica powder is 5.0 parts, perlite is 5.0 parts, magnesium stearate is 2.0 parts, and activated clay is 0.5 parts.

[0105] Application Example 12 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the modified ammonium polyphosphate prepared in example 3 is replaced with the modified ammonium polyphosphate prepared in example 5.

[0106] Application Example 13 The raw materials and preparation method of the ultrafine dry powder fire extinguishing agent in this comparative example are similar to those in application example 1, except that the modified ammonium polyphosphate prepared in example 3 is replaced with the modified ammonium polyphosphate prepared in example 6.

[0107] Comparative Example 1 The preparation method of this comparative example of modified ammonium polyphosphate is similar to that of Example 1, except that the macromolecular silane coupling agent is replaced with silane coupling agent KH550.

[0108] Comparative Example 2 The preparation method of this comparative example of modified ammonium polyphosphate is similar to that of Example 1, except that the macromolecular silane coupling agent is replaced with silane coupling agent KH570.

[0109] Comparative Example 3 The preparation method of this comparative example of modified ammonium polyphosphate is similar to that of Example 1, except that the macromolecular silane coupling agent is used to replace silane coupling agents KH550 and KH570 in a 1:1 molar ratio.

[0110] Comparative Example 4 The preparation method of the modified ammonium polyphosphate in this comparative example is similar to that in Example 1, except that the mass ratio of the ammonium polyphosphate to the macromolecular silane coupling agent is 100:0.3.

[0111] Comparative Example 5 This comparative example of an ultrafine dry powder fire extinguishing agent is similar to that in Application Example 1, except that modified ammonium polyphosphate is replaced with ammonium polyphosphate in the raw materials of the fire extinguishing agent.

[0112] Comparative Example 6 This comparative example of an ultrafine dry powder fire extinguishing agent is similar to that of Application Example 1, except that the modified ammonium polyphosphate in the fire extinguishing agent raw materials is replaced with the modified ammonium polyphosphate prepared in Comparative Example 1.

[0113] Comparative Example 7 This comparative example of an ultrafine dry powder fire extinguishing agent is similar to that of Application Example 1, except that the modified ammonium polyphosphate in the fire extinguishing agent raw materials is replaced with the modified ammonium polyphosphate prepared in Comparative Example 2.

[0114] Comparative Example 8 This comparative example of an ultrafine dry powder fire extinguishing agent is similar to that of Application Example 1, except that the modified ammonium polyphosphate in the fire extinguishing agent raw materials is replaced with the modified ammonium polyphosphate prepared in Comparative Example 3.

[0115] Comparative Example 9 This comparative example of an ultrafine dry powder fire extinguishing agent is similar to that in Application Example 1, except that silicone oil is not added to the raw materials of the fire extinguishing agent, but is replaced with an equal mass of modified ammonium polyphosphate.

[0116] Comparative Example 10 This comparative example of an ultrafine dry powder fire extinguishing agent is similar to that of Application Example 1, except that fumed silica is not added to the raw materials of the fire extinguishing agent, but is replaced with an equal mass of modified ammonium polyphosphate.

[0117] Comparative Example 11 This comparative example of an ultrafine dry powder fire extinguishing agent is similar to that of Application Example 1, except that in the preparation method, all raw materials are mixed and ground at a grinding speed of 500 r / min for 1 h.

[0118] Experimental Example 1 The agglomeration rate and solubility of the modified ammonium polyphosphate and unmodified ammonium polyphosphate prepared in Examples 1-7 and Comparative Examples 1-4 were tested respectively, and the results are shown in Table 2.

[0119] The clumping rate was tested using the following method: (1) Take 10g of the raw material to be tested with a particle size of 250 mesh and put it into a 250mL beaker. Add 50ml of pure water to a 120*150mm specimen bottle. Place the beaker into the specimen bottle and cover the top of the beaker with a transparent glass plate. Figure 5 As shown.

[0120] (2) Place the entire experimental apparatus in an oven at 60°C and let it stand for 24 hours. Then take it out and place it at room temperature for 24 hours. Repeat this process 3 times and then take out the powder.

[0121] (3) Pass the powder through a 50-mesh sieve. Powder with a particle size larger than 50 mesh will not pass through the sieve, which is considered to be agglomerated. Weigh the mass of the agglomerated powder as mg, and the agglomeration rate = m / 10 × 100%. When the agglomeration rate is ≤20%, the material can be considered to have good anti-agglomeration properties.

[0122] The reason for covering the top of the beaker with a transparent glass plate is to prevent water droplets condensing on the top of the specimen bottle from falling into the beaker, causing powder to clump together and affecting the accuracy of the experiment.

[0123] Solubility is tested using the following method: Take 5g of the raw material powder to be tested and dissolve it in 100g of water. Observe the dissolution of the powder as shown in Table 2. √ represents complete dissolution, and ○ represents incomplete dissolution with flocculent matter.

[0124] Table 2

[0125] As shown in Table 2, the agglomeration rate of the modified ammonium polyphosphate prepared by the method of the present invention is ≤8.3%, preferably 4.1~8.3%.

[0126] During storage, the gaps formed between APP particles during contact create capillaries that absorb moisture from the air. This moisture, accumulating on the particle surface, dissolves the APP, forming a saturated solution. As the temperature rises, the concentration of the saturated solution increases; as the temperature drops, the solution becomes supersaturated, causing crystals to precipitate. Alternatively, as the moisture evaporates, the solution becomes supersaturated again, also leading to crystal precipitation. Over time, this process repeats itself, and these crystals combine to form crystal bridges, binding the particles together and gradually forming large clumps.

[0127] When APP is coated with a silane coupling agent, the agglomeration rate decreases significantly; however, this reduces the solubility of APP, resulting in flocculent precipitates in aqueous solutions. Comparing Comparative Example 1 and Comparative Example 2, it can be seen that KH550, containing the hydrophilic group -NH3, compared to the more hydrophobic KH570, produces APP-coated powder with a higher agglomeration rate, but its solubility in water is stronger.

[0128] Compared with Comparative Example 1, Comparative Example 3 uses a combination of hydrophilic and hydrophobic silane coupling agents. After the APP powder is coated with the silane coupling agent, the agglomeration rate is lower than that of APP coated with only hydrophilic silane coupling agent. The solution in water also has only a small amount of flocculent precipitate. Since KH550 has good solubility, the solubility of the two after being combined is lower than that of APP coated with only hydrophobic silane coupling agent.

[0129] When two silane coupling agents are used in combination, a small amount of flocculent precipitate may occur. This invention addresses this issue by hydrolyzing and condensing the two silane coupling agents to generate a macromolecular silane coupling agent, which is then used to coat APP. The results showed that coating APP with the macromolecular silane coupling agent not only reduced the agglomeration rate but also did not affect its solubility.

[0130] Compared with Examples 1-4, Comparative Example 4 has a coating amount of 0.5-1.5% for the condensed silane coupling agent KH-Si. At this coating amount, the solubility and anti-caking ability can be balanced, and the agglomeration rate is <10%. When the coating amount is further increased (compared with Examples 1-3 in Example 4), the solubility decreases and the anti-caking ability increases. When the coating amount is reduced, the solubility increases and the anti-caking ability decreases.

[0131] As shown in Examples 1-4, increasing the coating amount of the silane coupling agent improves the anti-caking ability. However, when the coating amount increases to the level of Example 4, the solubility decreases, resulting in flocculent precipitate. Compared to Example 2, Example 5 shows that increasing the amount of KH550 in the synthesized macromolecular silane coupling agent improves the anti-caking ability. Examples 6 and 7 demonstrate that increasing the amount of KH570 in the synthesized macromolecular silane coupling agent improves the anti-caking ability, but decreases the solubility, resulting in flocculent precipitate in Example 7.

[0132] This is because the macromolecular silane synthesized in this invention has longer hydrophobic segments than monomolecular silane, which reduces the wetting of small water droplets on the APP surface and provides better hydrophobicity. Furthermore, the longer hydrophobic segments interfere with crystal bridge formation, reducing the strength of the formed crystal bridges and making it easier to break up APP powder agglomerates. The improved solubility is due to the fact that small-molecule silanes are randomly dispersed at various points in the APP powder, causing some APP powder to bind excessive amounts of small-molecule silanes, forming flocculent precipitates. However, with the same mass of silane coupling agent, the macromolecular silane binds to the APP powder only at the binding sites, resulting in more uniform dispersion in the APP powder and thus improved solubility.

[0133] It should be noted that the coating amount in this invention refers to the percentage of the mass of the macromolecular silane coupling agent to the mass of the ammonium polyphosphate.

[0134] Experimental Example 2 The performance of the extinguishing agents in Application Examples 1-13 and Comparative Examples 5-11 was tested according to GA578-2005. The results are shown in Table 3.

[0135] Table 3

[0136] As shown in Table 3, the extinguishing agent prepared by the present invention has a water content ≤0.11%, preferably 0.06~0.11%, a moisture absorption rate ≤0.93%, preferably 0.43~0.93%, and meets the requirements for water repellency. It also has an anti-caking property (penetration) ≥39.8mm, preferably 39.8~44.2mm, and 90% of the particles have a diameter ≤15.30μm, preferably 8.70~15.30μm.

[0137] Furthermore, based on Table 3, the following conclusions can be drawn: (1) Through application examples 1, 4 and 5, it can be seen that increasing or decreasing the amount of surfactant will cause the particle size D90 to increase. (2) Through application examples 1, 6 and 7, it can be seen that increasing the amount of silicone oil will cause the particle size D90 to increase, and decreasing the amount of silicone oil will cause the moisture absorption rate to increase; in comparative example 9, the absence of silicone oil will cause the moisture absorption rate and particle size D90 to increase. (3) Through Application Examples 1, 8, and 9, it can be seen that increasing the amount of fumed silica increases the moisture absorption rate, while decreasing the amount of fumed silica increases the particle size D90. In Comparative Example 10, the absence of fumed silica results in a further increase in the particle size D90. In Application Example 1, the amount of surfactant (sodium dodecylbenzenesulfonate) was 1 part, the amount of silicone oil was 3 parts, and the amount of fumed silica was 4.3 parts. Both the moisture absorption rate and the particle size D90 remained relatively low, indicating that the hydrophobic ultrafine dry powder fire extinguishing agent performed well.

[0138] In Application Example 1 and Comparative Example 5, the fire extinguishing agent made of modified ammonium polyphosphate meets the requirements of a hydrophobic ultrafine dry powder fire extinguishing agent, but its moisture absorption rate and particle size D90 are relatively large. Comparative Example 6 uses KH550 coating, Comparative Example 7 uses KH570 coating, and Comparative Example 8 uses the same proportion of KH550 and KH570 coating. The moisture absorption rate and particle size D90 are lower than those of the uncoated Comparative Example 5, but the performance is worse than that of Application Example 1.

[0139] In Application Example 1, the ratio of ammonium polyphosphate to macromolecular silane coupling agent was 100:1; in Application Example 2, the ratio was 100:0.5; and in Application Example 3, the ratio was 100:2.5. As the amount added gradually increased, the moisture absorption rate and particle size D90 gradually decreased.

[0140] Compared with Application Example 1, Comparative Example 11 changed the process by mixing all the raw materials together and grinding them. The moisture absorption rate was higher and the particle size D90 did not meet the requirements, indicating that the product produced by this process was not effective.

[0141] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a macromolecular silane coupling agent, characterized in that, Includes the following steps: (1) Place silane coupling agent KH550 and silane coupling agent KH570 in a solvent, stir and mix evenly to obtain a mixture; (2) The pH of the mixture is lowered, and the mixture is stirred at room temperature to carry out hydrolysis to obtain the hydrolysis product; (3) Increase the pH of the hydrolysis product, raise the temperature, react with stirring, cool down, purify and wash to obtain the macromolecular silane coupling agent.

2. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of the silane coupling agent KH550 and the silane coupling agent KH570 is 1:2-2:

1.

3. The preparation method according to claim 1, characterized in that, In step (1), the stirring rate is 200-400 r / min and the stirring time is 5-20 min.

4. The preparation method according to any one of claims 1-3, characterized in that, In step (2), the pH value is reduced to 4-6 and the hydrolysis time is 2-4 hours.

5. The preparation method according to any one of claims 1-3, characterized in that, In step (2), the stirring rate is 200-400 r / min and the stirring time is 2-4 h.

6. The preparation method according to any one of claims 1-3, characterized in that, In step (3), the pH value is increased by 8~10.

7. The preparation method according to any one of claims 1-3, characterized in that, In step (3), the temperature is raised to 50-60℃, and the stirring rate is kept constant to continue the reaction for 0.5-2h.

8. A macromolecular silane coupling agent prepared by the method according to any one of claims 1-7, characterized in that, The structural formula of the macromolecular silane coupling agent is as follows: ； Where n is the number of repeating units, and the average value of n is 1 to 3.

9. The application of a macromolecular silane coupling agent prepared by the method of any one of claims 1-7 or the macromolecular silane coupling agent of claim 8 in the modification of ammonium polyphosphate.

10. An ultrafine dry powder fire extinguishing agent, characterized in that, This includes macromolecular silane coupling agents prepared by the method described in any one of claims 1-7, or polyphosphate amines modified with the macromolecular silane coupling agent described in claim 8.

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