A modified process for the production of antimony trioxide

Abstract

This invention relates to the field of inorganic materials, specifically to a modification process for antimony trioxide. The process involves surface modification of antimony trioxide particles using a double-bonded silane coupling agent to obtain modified antimony trioxide; free radical polymerization of the modified antimony trioxide with polyvinyl chloride and vinylpyridine to obtain hybrid particles; dispersion of the hybrid particles in ethanol, followed by the addition of rare earth binary complexes for coordination reaction. The modified antimony trioxide obtained by this invention can significantly improve the flame retardant properties and mechanical strength of polyvinyl chloride materials.

Description

Technical Field

[0001] This invention relates to the field of inorganic materials, specifically to a modification process for antimony trioxide. Background Technology

[0002] Antimony trioxide, as an important inorganic flame retardant synergist, is widely used in the flame retardant modification of polymers such as polyvinyl chloride (PVC). Its flame retardant mechanism mainly involves synergistic action with halogens, generating volatile antimony halides during combustion, which capture free radicals in the gas phase, thereby interrupting the combustion chain reaction. However, unmodified antimony trioxide powder has a highly polar surface, easily absorbing moisture from the air to form polar groups, leading to powder agglomeration. Meanwhile, PVC and other polymers typically have non-polar surfaces, resulting in poor compatibility between the two. Direct blending makes uniform dispersion difficult, not only affecting the synergistic flame retardant effect but also degrading the mechanical properties of the composite material.

[0003] To address the aforementioned issues, surface organic modification of antimony trioxide has become an industry consensus. Common modification methods include coupling agent modification (such as silane coupling agents, aluminate coupling agents, titanate coupling agents, etc.), surfactant modification, and in-situ polymerization modification. Among these, coupling agent modification introduces organic functional groups onto the surface of inorganic particles through chemical bonding, effectively reducing surface energy and improving compatibility with the resin matrix. However, traditional coupling agent modification still has limitations. The modified particle surface is only coated with a small molecule organic layer, which is prone to desorption during high-shear processing, and lacks strong chemical bonding with the matrix resin, resulting in dispersion stability that needs further improvement.

[0004] To address the aforementioned technical issues, this field needs to develop a novel antimony trioxide modification process. This process involves anchoring polymer segments and rare earth functional components onto the surface of antimony trioxide particles through chemical bonding, thereby constructing hybrid particles with a core-shell structure. The aim is to improve the compatibility of inorganic particles with polymer materials such as polyvinyl chloride (PVC) while introducing the synergistic flame-retardant and smoke-suppressing functions of rare earth components, thus achieving synergistic optimization of flame-retardant and mechanical properties. Summary of the Invention

[0005] Purpose of the invention: To address the above-mentioned technical problems, this invention proposes a modification process for antimony trioxide.

[0006] The technical solution adopted is as follows: A modification process for antimony trioxide includes the following steps: Surface modification of antimony trioxide particles was carried out using a double-bonded silane coupling agent to obtain modified antimony trioxide. The modified antimony trioxide was subjected to free radical polymerization with polyvinyl chloride and vinylpyridine to obtain hybrid particles; The obtained hybrid particles were dispersed in ethanol, and a rare earth binary complex was added to carry out a coordination reaction. After the reaction was completed, the particles were separated and dried to obtain the final product.

[0007] The core design concept of this invention is as follows: First, polymerizable carbon-carbon double bond active sites are introduced onto the surface of antimony trioxide using a double-bonded silane coupling agent. Second, these surface double bonds are used to initiate free radical polymerization reactions with polyvinyl chloride (PVC) macromolecules and vinylpyridine monomers. During this process, the active hydrogen on the PVC chain can generate free radicals under the action of an initiator to participate in polymerization, thereby chemically grafting PVC segments onto the particle surface. Simultaneously, polyvinylpyridine segments formed by the polymerization of vinylpyridine monomers are also incorporated through copolymerization, ultimately forming hybrid particles with antimony trioxide as the core and PVC / polyvinylpyridine copolymer as the shell. Finally, utilizing the lone pair electrons of the nitrogen atom on the pyridine ring in the polyvinylpyridine segment, which can coordinate with rare earth ions, a rare earth binary complex with synergistic flame-retardant function is anchored onto the surface of the hybrid particles through a coordination reaction. The final product obtained is a functionalized particle with a multi-level structure: the core is the flame retardant synergist antimony trioxide, the middle layer is a polyvinyl chloride / polyvinylpyridine copolymer segment with the same chemical structure as polyvinyl chloride matrix, and the outer layer is an anchored rare earth complex.

[0008] As a preferred embodiment of the present invention, the double-bonded silane coupling agent is Methacryloxypropyltrimethoxysilane, or KH-570. The methacryloyloxy group in KH-570 provides the carbon-carbon double bond required for polymerization, which is a key bridge for establishing chemical bonds between antimony trioxide and subsequent organic layers.

[0009] As a preferred embodiment of the present invention, the surface modification method is as follows: Antimony trioxide particles were added to a mixed solvent consisting of deionized water and anhydrous ethanol, and ultrasonically dispersed until uniform. Then, KH-570 was added, and the pH of the system was adjusted to 3-4 with acetic acid. The mixture was stirred at 55-75℃ for 2-6 hours. After the reaction was completed, the solid product was separated by centrifugation or filtration. The solid product was washed 2-3 times with anhydrous ethanol to remove the physically adsorbed coupling agent. Finally, it was vacuum dried at 60-80℃ to constant weight to obtain modified antimony trioxide.

[0010] In this preferred embodiment, a mixed solvent of deionized water and anhydrous ethanol (e.g., volume ratio 1:1-1:5) provides the medium for the hydrolysis of KH-570. Acidic conditions (pH 3-4) catalyze the hydrolysis of silanoxy groups, generating silanol groups (Si-OH). These silanol groups then undergo a condensation reaction with the hydroxyl groups (Sb-OH) on the surface of antimony trioxide, forming stable Sb-O-Si covalent bonds. The reaction temperature is controlled at 55-75℃ to ensure the reaction rate while avoiding excessive temperature that could lead to self-polymerization of the coupling agent. Ultrasonic dispersion helps break up the soft aggregates of antimony trioxide, increasing the reaction contact area and improving the uniformity of the modification effect.

[0011] As a preferred technical solution of the present invention, in step (2), the mass ratio of the modified antimony trioxide to polyvinyl chloride and vinylpyridine is 1:0.5-1:0.1-0.5.

[0012] Controlling this ratio aims to balance the thickness of the grafted layer with the controllability of the polymerization reaction. If the PVC ratio is too low, there will be insufficient PVC segments grafted onto the particle surface, limiting the effect of improving compatibility; if the ratio is too high, it may lead to excessive system viscosity, easy bridging and agglomeration between particles, and even the formation of a large amount of ungrafted homopolymer, increasing the difficulty of post-processing. The vinylpyridine ratio also needs to be optimized; too little will not provide enough coordination sites to anchor rare earth complexes; too much may lead to excessively long polyvinylpyridine segments or excessive homopolymer.

[0013] As a preferred embodiment of the present invention, the method for preparing hybrid particles is as follows: Modified antimony trioxide was dispersed in nitrobenzene to obtain a dispersion. Vinylpyridine and polyvinyl chloride were dissolved in another part of nitrobenzene to form a transparent solution. The two were mixed, and nitrogen gas was introduced to remove oxygen. A free radical initiator was added to carry out free radical polymerization. After the reaction was completed, the reaction solution was poured into methanol to collect the crude product. Then, methanol was used as an extractant for Soxhlet extraction and purification.

[0014] As another preferred embodiment of the present invention, the method for preparing hybrid particles is as follows: Modified antimony trioxide was dispersed in nitrobenzene and ultrasonically treated to obtain a uniform dispersion (denoted as solution A). A measured amount of vinylpyridine and polyvinyl chloride were dissolved in another portion of nitrobenzene and heated and stirred until completely dissolved (denoted as solution B). Under nitrogen protection, solution A and solution B were mixed evenly, and then a free radical initiator was added. The mixture was stirred at 60-70℃ for 8-24 hours. After the reaction was completed, the reaction solution was slowly added to a large amount of methanol and filtered. The crude product was placed in a Soxhlet extractor and purified for 24-48 hours using methanol as the extractant. Finally, the purified product was vacuum dried at 50-60℃ to constant weight to obtain hybrid particles.

[0015] In this preferred embodiment, nitrobenzene is a good solvent for polyvinyl chloride (PVC), capable of dissolving vinylpyridine monomer and PVC, and exhibiting good wetting and dispersing ability for modified antimony trioxide. Nitrogen gas is introduced to remove oxygen and prevent its inhibitory effect on free radical polymerization. The free radical initiator can be selected from commonly used oil-soluble initiators such as di(2-phenoxyethyl) percarbonate (BPPD), azobisisobutyronitrile (AIBN), and benzoyl peroxide (BPO). The polymerization temperature of 60-70℃ is determined based on the decomposition temperature range of the initiator to ensure a suitable free radical generation rate. Post-reaction methanol precipitation and Soxhlet extraction are crucial steps for removing impurities and obtaining a pure product, ensuring that the polymer chains in the final product are chemically bonded to the particle surface.

[0016] As a preferred embodiment of the present invention, in step (3), the rare earth binary complex is obtained by reacting a soluble rare earth salt with benzoylacetone. The preparation method is as follows: Soluble rare earth salts (such as cerium chloride, cerium nitrate, etc.) are dissolved in anhydrous ethanol, and benzoyl acetone is also dissolved in anhydrous ethanol. The benzoyl acetone ethanol solution is added dropwise to the rare earth salt ethanol solution under stirring. The pH is adjusted to 6-7, and the reaction is carried out at 50-70℃ for 1-3 hours. The mixture is then concentrated, cooled, filtered, washed, and dried to obtain the rare earth binary complex.

[0017] As a preferred embodiment of the present invention, the soluble rare earth salt is cerium chloride or its hydrate. Cerium is a rare earth element that is abundant, relatively inexpensive, and has good flame retardant and smoke-suppressing effects.

[0018] As a preferred embodiment of the present invention, in step (3), the mass ratio of the hybrid particles to the rare earth binary complex is 1:0.01-0.1. Controlling this ratio aims to ensure that the rare earth complex has sufficient loading on the particle surface to exert its effect, while avoiding excessive rare earth complex from undergoing multilayer adsorption or self-aggregation on the particle surface, which would affect dispersibility.

[0019] As a preferred embodiment of the present invention, in step (3), the temperature of the coordination reaction is 70-75℃ and the reaction time is 12-48h. At this temperature, it is beneficial for the full dispersion of hybrid particles and the diffusion and coordination of rare earth complexes.

[0020] The beneficial effects of this invention are: This invention provides a modification process for antimony trioxide. First, polymerizable carbon-carbon double bond active sites are introduced on the surface of antimony trioxide through a double-bonded silane coupling agent. This step utilizes the condensation reaction between silane hydrolysis and the hydroxyl groups on the antimony surface to establish a strong covalent bond connection, laying the foundation for subsequent chemical bonding at the organic-inorganic interface. Subsequently, these surface-anchored double bonds are used to perform free radical polymerization with polyvinyl chloride (PVC) and vinylpyridine. This allows PVC segments with the same chemical structure as the matrix resin to be covalently grafted onto the surface of antimony trioxide, forming a "homogeneous" polymer brush that is thermodynamically compatible with PVC. At the same time, polyvinylpyridine segments formed by the polymerization of vinylpyridine are also introduced through copolymerization, constructing a functional shell rich in nitrogen coordination sites on the particle surface. This chemically grafted core-shell structure allows the PVC segments on the surface of the inorganic particles to undergo sufficient segmental entanglement and even co-crystallization with the PVC molecular chains during subsequent blending with PVC. This fundamentally eliminates the interfacial tension between the inorganic and organic phases, achieving uniform dispersion at the nanoscale and avoiding the aggregation and phase separation problems caused by weak interfacial bonding in traditional physical blending or small molecule coupling agent modification.

[0021] Building upon this, utilizing the lone pair electrons of the nitrogen atom on the pyridine ring in the polyvinylpyridine chain, a pre-synthesized rare-earth binary complex is selectively anchored onto the surface of hybrid particles via a coordination reaction. The rare-earth complexes are firmly bound by coordination bonds rather than simple physical adsorption, ensuring their stability during processing and use. When the final product is used for flame-retardant modification of polyvinyl chloride (PVC), the highly dispersed antimony trioxide core efficiently captures hydrogen chloride produced by PVC decomposition and generates antimony trichloride, which enters the gas phase to capture combustion free radicals. Meanwhile, the surface-anchored rare-earth complexes catalyze the crosslinking of PVC into char in the condensed phase, forming... A dense and stable protective carbon layer is formed, which can not only isolate the transfer of heat and oxygen to the interior of the material, but also fix carbon elements in the condensed phase, thereby significantly inhibiting smoke generation. This forms a dual flame retardant mechanism of "gas phase capture of free radicals" and "condensed phase catalytic carbonization". At the same time, the presence of rare earth complexes further optimizes the interfacial interaction, so that the composite material can achieve a significant improvement in limiting oxygen index, a significant reduction in heat release and smoke release, and improved tensile strength. It achieves synergistic optimization of mechanical properties, flame retardant properties and smoke suppression properties, and shows a wide range of applications in polymer materials such as polyvinyl chloride. Attached Figure Description

[0022] Figure 1 This is a SEM image of the carbon layer after testing with a cone calorimeter on the sample of experimental group 1.

[0023] Figure 2 This is a SEM image of the carbon layer after cone calorimetry testing of the control group sample. Detailed Implementation

[0024] Unless otherwise specified in the examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Techniques not mentioned in this invention refer to existing technologies. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters. Example 1

[0025] A modification process for antimony trioxide includes the following steps: Weigh 100g of dried antimony trioxide (Nippon Concentrate Co., Ltd., average particle size...). The mixture was added to 500 ml of a mixed solvent of deionized water and anhydrous ethanol in a volume ratio of 1:4, and ultrasonically dispersed (400 W, 40 kHz) for 30 min. Then, 5 g of KH-570 was added, and the pH of the system was adjusted to 3-4 with acetic acid. The system was transferred to a three-necked flask equipped with a stirrer, thermometer, and reflux condenser, and stirred in a 65 °C water bath for 4 h. After the reaction was completed, the solid product was separated by centrifugation, washed three times with anhydrous ethanol, and finally dried in a 70 °C vacuum drying oven for 12 h to obtain KH-570 modified antimony trioxide.

[0026] Weigh 10g of KH-570 modified antimony trioxide and disperse it in 100ml of nitrobenzene. Sonicate for 30min to obtain solution A. Weigh 7.5g of polyvinyl chloride (SG-5) and 2.5g of 4-vinylpyridine and dissolve them in another 100ml of nitrobenzene. Stir and dissolve at 50℃ to obtain solution B. Mix solutions A and B thoroughly in a 500ml four-necked flask equipped with a stirrer, thermometer, nitrogen inlet tube, and reflux condenser. Purge with high-purity nitrogen for 30min to remove oxygen from the system. Then add 0.1g of initiator BPPD (dissolved in a small amount of nitrobenzene). Under nitrogen protection, heat to 70℃ and stir for 12h. After the reaction is complete, slowly pour the reaction solution into 2000ml of vigorously stirred methanol, filter, and collect the crude product. The crude product was wrapped in filter paper and placed in a Soxhlet extractor. Methanol was used as the extractant and the product was extracted for 36 hours. After extraction, the product was removed and dried in a vacuum drying oven at 50°C for 24 hours to obtain polyvinyl chloride / polyvinylpyridine / antimony trioxide hybrid particles.

[0027] 0.01 mol of cerium chloride hexahydrate was dissolved in 50 ml of anhydrous ethanol to obtain solution C. 0.06 mol of benzoylacetone was dissolved in 50 ml of anhydrous ethanol to obtain solution D. Solution D was slowly added dropwise to solution C with stirring, and the pH of the reaction solution was adjusted to 6.5. The reaction was then stirred in a 60°C water bath for 2 h. After the reaction was complete, the solution was concentrated, cooled, filtered, and the product was washed three times with cold anhydrous ethanol and dried in a 50°C vacuum drying oven for 12 h to obtain a rare earth binary complex. 5 g of polyvinyl chloride / polyvinylpyridine / antimony trioxide hybrid particles were dispersed in 100 ml of anhydrous ethanol and sonicated for 30 min. 0.25 g of the rare earth binary complex was then weighed and dissolved in 20 ml of anhydrous ethanol. The two were slowly mixed and stirred in a 70°C water bath for 24 h. After the reaction was complete, the mixture was brought to room temperature, the solid product was separated by centrifugation, washed three times with anhydrous ethanol, and dried in a 50°C vacuum drying oven for 12 h. Example 2

[0028] This comparative example is basically the same as Example 1, except that the proportions of KH-570 modified antimony trioxide, polyvinyl chloride, and vinylpyridine were adjusted, specifically as follows: KH-570 modified antimony trioxide: 10g Polyvinyl chloride (SG-5): 5g 4-Vinylpyridine: 1g. Example 3

[0029] This comparative example is basically the same as Example 1, except that the proportions of KH-570 modified antimony trioxide, polyvinyl chloride, and vinylpyridine were adjusted, specifically as follows: KH-570 modified antimony trioxide: 10g Polyvinyl chloride (SG-5): 10g 4-Vinylpyridine: 5g. Example 4

[0030] This comparative example is basically the same as Example 1, except that the proportions of KH-570 modified antimony trioxide, polyvinyl chloride, and vinylpyridine were adjusted, specifically as follows: KH-570 modified antimony trioxide: 10g Polyvinyl chloride (SG-5): 5g 4-Vinylpyridine: 5g. Example 5

[0031] This comparative example is basically the same as Example 1, except that the proportions of KH-570 modified antimony trioxide, polyvinyl chloride, and vinylpyridine were adjusted, specifically as follows: KH-570 modified antimony trioxide: 10g Polyvinyl chloride (SG-5): 10g 4-Vinylpyridine: 1g. Example 6

[0032] This comparative example is basically the same as Example 1, except for the ratio of polyvinyl chloride / polyvinylpyridine / antimony trioxide hybrid particles to rare earth binary complexes, which is as follows: Polyvinyl chloride / polyvinylpyridine / antimony trioxide hybrid particles: 5g Rare earth binary complex: 0.05g. Example 7

[0033] This comparative example is basically the same as Example 1, except for the ratio of polyvinyl chloride / polyvinylpyridine / antimony trioxide hybrid particles to rare earth binary complexes, which is as follows: Polyvinyl chloride / polyvinylpyridine / antimony trioxide hybrid particles: 5g Rare earth binary complex: 0.5g. Example 8

[0034] This comparative example is basically the same as Example 1, except that the temperature of the free radical polymerization is adjusted to 60°C.

[0035] Comparative Example 1 This comparative example is basically the same as Example 1, except that no modification treatment is performed on antimony trioxide; raw antimony trioxide powder (Nippon Concentrate Co., Ltd., average particle size) is used directly. ).

[0036] Comparative Example 2 This comparative example is basically the same as Example 1, except that in this comparative example, only antimony trioxide is modified with KH-570, without subsequent polymerization and coordination steps.

[0037] Comparative Example 3 This comparative example is basically the same as Example 1, except that in this comparative example, only antimony trioxide is modified with KH-570 and subjected to free radical polymerization, without subsequent coordination steps.

[0038] Performance testing: The antimony trioxide prepared in Examples 1-8 and Comparative Examples 1-3 of this invention were used as samples for corresponding performance tests.

[0039] The sample was mixed with PVC paste resin, dioctyl phthalate and calcium zinc stabilizer in a mass ratio of 0.06:1:0.45:0.03 to obtain a mixture, which was designated as experimental group 1-11. The control group did not add the sample. The mixture was placed in an extruder and melt-extruded at a temperature range of 140-160℃ to prepare a composite material. Then, it was placed in a micro injection molding machine and injection molded at 145℃ with a pressure of 15MPa. Finally, it was cut into the test strips required for performance testing.

[0040] ①Oxygen index data were collected using a JF-3 oxygen index tester. The test standard was in accordance with GB / T 2406-2009 Oxygen Index Determination Method. The sample size was 100mm×6.5mm×3mm.

[0041] ② Flame retardant performance data were collected using a cone calorimeter, with testing standards conforming to ISO 5660-1:2015. The sample size was 100mm×100mm×3mm, and the radiation intensity was selected as... .

[0042] ③ Tensile properties were tested using an electronic universal testing machine according to GB / T1040-2006 Test Method for Tensile Properties of Plastics, at a speed of 50.0 mm / min.

[0043] The test results are shown in Table 1 below: Table 1: As shown in Table 1 above, the antimony trioxide modified by the method of the present invention can greatly improve the flame retardant properties and mechanical strength of polyvinyl chloride materials.

[0044] The comparison of experimental groups 1-11 shows that the coating of KH-570 improves the interfacial compatibility between antimony trioxide particles and polyvinyl chloride matrix, reduces stress defects caused by agglomerates, and the improved dispersion allows the flame retardant synergistic effect of antimony trioxide particles to be fully exerted. However, since the surface is only a small molecular layer, there is no chemical bond with the matrix and no rare earth elements are introduced, resulting in a limited overall improvement.

[0045] A copolymer layer was grafted onto the surface of antimony trioxide particles via free radical polymerization, forming a robust "anchoring" structure. This enabled the particles to achieve nanoscale dispersion in the polyvinyl chloride matrix, significantly reducing internal defects and improving mechanical properties. Furthermore, the uniformly dispersed antimony trioxide could react more effectively with the hydrogen chloride produced by the decomposition of polyvinyl chloride, thus improving flame retardant efficiency.

[0046] Rare earth elements are introduced onto the surface of antimony trioxide through the coordination reaction of rare earth ions with pyridine. During combustion, these rare earth elements catalyze the cross-linking of polyvinyl chloride (PVC) into char, forming a denser char layer that effectively blocks the escape of flammable gases and heat transfer. Simultaneously, the carbon elements are fixed within the char layer rather than released into the flue gas. The catalytic char formation of rare earth elements, combined with the antimony-halogen synergy, forms a dual flame-retardant mechanism of "condensed phase + gas phase," significantly improving flame-retardant performance. The anchored rare earth complexes may further increase the polarity of the particle surface or its interaction with the matrix, and the good dispersion prevents the rare earth elements from agglomerating into new defects, thus further enhancing tensile strength.

[0047] Figure 1 This is a SEM image of the carbon layer after testing with a cone calorimeter on the first sample of experimental group 1. Figure 2 The image shows a SEM image of the carbon layer after testing with a cone calorimeter on the control group 1 sample. It can be seen that the addition of the sample in Example 1 can catalyze carbonization, isolate gas and heat transfer, and improve flame retardant performance.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modification process for antimony trioxide, characterized in that, include: Modified antimony trioxide was obtained by surface modification of antimony trioxide particles using a double-bonded silane coupling agent. Modified antimony trioxide was subjected to free radical polymerization with polyvinyl chloride and vinylpyridine to obtain hybrid particles; The hybrid particles are dispersed in ethanol, and then rare earth binary complexes are added to carry out a coordination reaction.

2. The antimony trioxide modification process as described in claim 1, characterized in that, The double-bonded silane coupling agent is KH-570.

3. The antimony trioxide modification process as described in claim 2, characterized in that, The surface modification methods are as follows: Antimony trioxide particles are added to a mixed solvent consisting of deionized water and anhydrous ethanol, ultrasonically dispersed, and then KH-570 is added. The pH of the system is adjusted to 3-4 with acetic acid, and the reaction is stirred at 55-75℃. After the reaction is completed, the solid is separated, washed, and dried.

4. The antimony trioxide modification process as described in claim 1, characterized in that, The mass ratio of modified antimony trioxide to polyvinyl chloride and vinylpyridine is 1:0.5-1:0.1-0.

5.

5. The antimony trioxide modification process as described in claim 1, characterized in that, The preparation method of hybrid particles is as follows: Modified antimony trioxide was dispersed in nitrobenzene to obtain a dispersion. Vinylpyridine and polyvinyl chloride were dissolved in another part of nitrobenzene to form a transparent solution. The two were mixed, and nitrogen gas was introduced to remove oxygen. A free radical initiator was added to carry out free radical polymerization. After the reaction was completed, the reaction solution was poured into methanol to collect the crude product. Then, methanol was used as an extractant for Soxhlet extraction and purification.

6. The antimony trioxide modification process as described in claim 5, characterized in that, The temperature for free radical polymerization is 60-70℃.

7. The antimony trioxide modification process as described in claim 1, characterized in that, The rare earth binary complex is obtained by reacting soluble rare earth salts with benzoylacetone.

8. The antimony trioxide modification process as described in claim 7, characterized in that, The soluble rare earth salt is cerium chloride or its hydrate.

9. The antimony trioxide modification process as described in claim 1, characterized in that, The mass ratio of the hybrid particles to the rare earth binary complex is 1:0.01-0.

1.

10. The antimony trioxide modification process as described in claim 1, characterized in that, The temperature for the coordination reaction is 70-75℃.

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