Composite synergistic flame retardant, preparation method and application thereof

Abstract

The application discloses a composite synergistic flame retardant, a preparation method and application thereof, and belongs to the technical field of flame retardant materials. Antimony trioxide nanoparticles are loaded on the inner surface and the outer surface of tubular kaolin, and then are modified by using a coupling agent to obtain the composite synergistic flame retardant; the particle size of the antimony trioxide nanoparticles is 30-80 nm; the mass ratio of the tubular kaolin to the antimony trioxide nanoparticles is (50-60):(40-50), and the mass ratio of the total mass of the tubular kaolin and the antimony trioxide nanoparticles to the mass of the coupling agent is 100:(1-3). The composite synergistic flame retardant takes the tubular kaolin as a matrix and loads the antimony trioxide nanoparticles, so that the mechanical properties and the flame retardant properties are further improved while the cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant materials technology, specifically relating to a composite synergistic flame retardant, its preparation method, and its application. Background Technology

[0002] Kaolin can form a relatively dense network structure at high temperatures, which provides good thermal insulation. At the same time, kaolin decomposes at high temperatures to produce solid products such as SiO2 and Al2O3. These products cover the material surface and form a protective layer, thus playing a certain role in synergistic flame retardancy. However, the synergistic flame retardancy effect of using kaolin alone is not significant.

[0003] Antimony trioxide is currently the most widely used and highly efficient flame retardant synergist, significantly improving flame retardant effects. However, its high price leads to high downstream costs. Furthermore, antimony trioxide exhibits dispersion issues in plastic matrices, affecting the mechanical properties of plastic products to some extent. Patent application CN112457528A discloses a composite flame retardant consisting of layered double hydroxide, antimony trioxide, and decabromodiphenyl ethane. This composite flame retardant is prepared from layered double hydroxide intercalated with tripolyphosphate and covalently modified with sodium oleate, antimony trioxide, and decabromodiphenyl ethane. The limiting oxygen index of this composite flame retardant is 24.3%–24.9%, and the tensile strength is 17.6–19.3 MPa.

[0004] Therefore, it is necessary to develop a low-cost, high-performance flame retardant synergist. Summary of the Invention

[0005] The first objective of this invention is to provide a composite synergistic flame retardant that uses tubular kaolin as a matrix and loads antimony trioxide, thereby reducing costs while further improving mechanical and flame retardant properties.

[0006] The second objective of this invention is to provide a method for preparing a composite synergistic flame retardant.

[0007] The third objective of this invention is to provide an application of a composite synergistic flame retardant in the preparation of flame retardant materials.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a composite synergistic flame retardant, which is obtained by loading antimony trioxide nanoparticles onto the inner and outer surfaces of tubular kaolin, followed by modification with a coupling agent; the particle size of the antimony trioxide nanoparticles is 30-80 nm; the mass ratio of the tubular kaolin to the antimony trioxide nanoparticles is (50-60):(40-50), and the mass ratio of the total mass of the tubular kaolin and the antimony trioxide nanoparticles to the mass of the coupling agent is 100:(1-3).

[0009] Furthermore, the tubular kaolin has a purity of not less than 95% and a fineness of not more than 5000 mesh.

[0010] Furthermore, the coupling agent is one or more of titanate coupling agents, aluminate coupling agents, and organosilicon.

[0011] Secondly, the present invention provides a method for preparing the composite synergistic flame retardant as described above, comprising the following steps: S1: Dissolve antimony salt in the first solvent to obtain solution A, disperse tubular kaolin in the second solvent and adjust the pH to acidic to obtain solution B; S2: Add solution A obtained from S1 to solution B obtained from S1, add alkaline solution to adjust the pH to 5-8, stir, and then age under vacuum pressure to obtain a colloid; S3: After the colloid obtained in S2 is first dried, it is pulverized and washed to obtain the composite matrix; S4: Mix the composite matrix obtained in S3 with the coupling agent evenly, granulate, and perform a second drying to obtain the composite synergistic flame retardant.

[0012] Furthermore, the antimony salt in S1 is one or more of antimony chloride, antimony nitrate, and antimony acetate; the mass ratio of the antimony salt to the tubular kaolin is (62.6-105.6):50.

[0013] Furthermore, the mass ratio of the antimony salt to the first solvent in S1 is 1:(1-2), and the first solvent is ethanol; the mass ratio of the tubular kaolin to the second solvent is 1:(1-2), and the second solvent is water; adjusting the pH to acidity includes adjusting the pH to 1-3.

[0014] Furthermore, the alkaline solution in S2 is dilute ammonia water with a mass fraction of 5%, the vacuum degree is 0.05-0.1 MPa, and the pressure holding and aging time is 12-18 h.

[0015] Furthermore, the temperature of the first drying in S3 is 100–180°C, and the time is 8–16 h.

[0016] Furthermore, in S4, the second drying temperature is 80–120°C, the time is 1–3 h, and the mass of the coupling agent is 1%–3% of the mass of the composite matrix.

[0017] Thirdly, the present invention provides an application of the composite synergistic flame retardant as described above in the preparation of flame retardant materials.

[0018] The beneficial effects of this invention are: The composite synergistic flame retardant of this invention uses tubular kaolin as a carrier and loads antimony trioxide nanoparticles onto the tubular kaolin, constructing a composite structure of tubular kaolin and antimony trioxide nanoparticles. The tubular kaolin and antimony trioxide nanoparticles can exert a synergistic flame retardant effect, thereby improving the flame retardant performance of the composite synergistic flame retardant.

[0019] The composite synergistic flame retardant of this invention utilizes the hollow tubular structure of tubular kaolin, which can form an air insulation layer within the cavity. This layer can delay heat transfer to a certain extent during combustion, thereby improving the flame retardant performance of the material. Furthermore, tubular kaolin is widely available and inexpensive. By combining it with antimony trioxide nanoparticles, the amount of antimony trioxide nanoparticles used can be reduced while maintaining the flame retardant effect, thus helping to lower the cost of flame retardant materials.

[0020] In the composite synergistic flame retardant of the present invention, tubular kaolin serves as a carrier for antimony trioxide nanoparticles, which can disperse and load the antimony trioxide nanoparticles, reduce the aggregation between them, thereby improving the dispersion uniformity of antimony trioxide nanoparticles in the composite flame retardant material matrix. This is beneficial for fully utilizing the flame retardant effect of antimony trioxide nanoparticles and improving the overall performance of the resulting composite flame retardant material. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the composite synergistic flame retardant in Example 1; Figure 2 The images show SEM images of tubular kaolin and composite synergistic flame retardant from Example 1. In the images, A is the SEM image of tubular kaolin and B is the SEM image of composite synergistic flame retardant from Example 1. Figure 3 The XRD pattern of the composite synergistic flame retardant in Example 1 is shown below. Figure 4 This is a schematic diagram of the composite synergistic flame retardant in the plastic matrix of Example 1. Detailed Implementation

[0022] The following will provide further details with reference to embodiments of the present invention. Example 1

[0023] The preparation method of the composite synergistic flame retardant in Example 1 includes the following steps: Weigh 62.6 g of antimony chloride and dissolve it in 80 g of anhydrous ethanol to obtain solution A.

[0024] Weigh 50 g of tubular kaolin and evenly disperse it in 50 g of water, adjusting the pH to 2.5 to obtain solution B. The tubular kaolin must have a purity of not less than 95% and a fineness of not more than 5000 mesh.

[0025] Slowly add the obtained solution A to the obtained solution B, stir and mix for 15 minutes to obtain solution C.

[0026] The pH was adjusted to 6 by slowly adding 5% dilute ammonia to solution C, and after stirring, the solution was vacuumed and aged under vacuum conditions of 0.08 MPa for 12 h to obtain the colloid.

[0027] The obtained colloid was dried at 120℃ for 10 h, then removed, crushed, and washed to obtain the composite matrix.

[0028] The obtained composite matrix was mixed evenly with 1.3 g of aluminate coupling agent DL411, granulated, and then dried at 110℃ for 1 h to obtain the composite synergistic flame retardant.

[0029] The composite synergistic flame retardant of Example 1 was prepared by the preparation method of the composite synergistic flame retardant of Example 1. In the obtained composite synergistic flame retardant, antimony trioxide was loaded on the inner and outer surfaces of tubular kaolin in the form of nanoparticles. The particle size of the antimony trioxide nanoparticles was 45 nm. The mass ratio of tubular kaolin to antimony trioxide nanoparticles was 55:40. The mass ratio of the total mass of tubular kaolin and antimony trioxide nanoparticles to the mass of the coupling agent was 66:1.

[0030] Figure 2 The image shows a SEM image of tubular kaolin and a composite synergistic flame retardant from Example 1. Figure 2 As can be seen from A and B, a layer of particulate matter is generated on the surface of the tubular kaolin in the composite synergistic flame retardant, and it is tightly bound to the kaolin. Figure 3 The image shows the XRD pattern of the composite synergistic flame retardant of Example 1. As can be seen from the image, kaolin, Sb2O3 and Sb4O5Cl2 were detected simultaneously in the composite synergistic flame retardant of Example 1, indicating that Sb2O3 and Sb4O5Cl2 were generated on the surface of the tubular kaolin, thus demonstrating the successful preparation of the composite synergistic flame retardant of Example 1. Example 2

[0031] The preparation method of the composite synergistic flame retardant in Example 2 includes the following steps: 78.25 g of antimony chloride was weighed and dissolved in 80 g of anhydrous ethanol to obtain solution A.

[0032] Weigh 50 g of tubular kaolin and evenly disperse it in 50 g of water, then adjust the pH to 3 to obtain solution B. The tubular kaolin must have a purity of not less than 95% and a fineness of not more than 5000 mesh.

[0033] Slowly add the obtained solution A to the obtained solution B, stir and mix for 15 minutes to obtain solution C.

[0034] The pH was adjusted to 7 by slowly adding 5% dilute ammonia to solution C, and after stirring, the solution was vacuumed and aged under vacuum conditions of 0.08 MPa for 16 h to obtain the colloid.

[0035] The obtained colloid was dried at 120°C for 12 h, then removed, crushed, and washed to obtain the composite matrix.

[0036] The obtained composite matrix was mixed evenly with 0.95 g of aluminate coupling agent DL411, granulated, and then dried for 1 h at 110°C to obtain the composite synergistic flame retardant.

[0037] The composite synergistic flame retardant of Example 2 was prepared by the preparation method of the composite synergistic flame retardant of Example 2. In the obtained composite synergistic flame retardant, antimony trioxide was loaded on the inner and outer surfaces of tubular kaolin in the form of nanoparticles. The particle size of the antimony trioxide nanoparticles was 60 nm. The mass ratio of tubular kaolin to antimony trioxide nanoparticles was 50:45. The mass ratio of the total mass of tubular kaolin and antimony trioxide nanoparticles to the mass of the coupling agent was 100:1. Example 3

[0038] The preparation method of the composite synergistic flame retardant in Example 3 includes the following steps: 105.6 g of antimony nitrate was weighed and dissolved in 150 g of anhydrous ethanol to obtain solution A.

[0039] Weigh 50 g of tubular kaolin and evenly disperse it in 60 g of water, adjusting the pH to 1.5 to obtain solution B. The tubular kaolin must have a purity of not less than 95% and a fineness of not more than 5000 mesh.

[0040] Slowly add the obtained solution A to the obtained solution B, stir and mix for 15 minutes to obtain solution C.

[0041] The pH was adjusted to 6 by slowly adding 5% dilute ammonia to solution C, and after stirring, the solution was vacuumed and aged under vacuum conditions of 0.06 MPa for 12 h to obtain the colloid.

[0042] The obtained colloid was dried at 150℃ for 8 hours, then removed, crushed, and washed to obtain the composite matrix.

[0043] The obtained composite matrix was mixed evenly with 1.4 g of titanate coupling agent GR-110, granulated, and then dried for 2 h at 120℃ to obtain the composite synergistic flame retardant.

[0044] The composite synergistic flame retardant of Example 3 was prepared by the preparation method of the composite synergistic flame retardant of Example 3. In the obtained composite synergistic flame retardant, antimony trioxide was loaded on the inner and outer surfaces of tubular kaolin in the form of nanoparticles. The particle size of the antimony trioxide nanoparticles was 55 nm. The mass ratio of tubular kaolin to antimony trioxide nanoparticles was 50:45. The mass ratio of the total mass of tubular kaolin and antimony trioxide nanoparticles to the mass of the coupling agent was 68:1. Example 4

[0045] The preparation method of the composite synergistic flame retardant in Example 4 includes the following steps: Weigh 62.6 g of antimony chloride and dissolve it in 80 g of anhydrous ethanol to obtain solution A.

[0046] Weigh 50 g of tubular kaolin and evenly disperse it in 50 g of water, adjusting the pH to 2.5 to obtain solution B. The tubular kaolin must have a purity of not less than 95% and a fineness of not more than 5000 mesh.

[0047] Slowly add the obtained solution A to the obtained solution B, stir and mix for 15 minutes to obtain solution C.

[0048] The pH was adjusted to 5 by slowly adding 5% dilute ammonia to solution C, and after stirring, the solution was vacuumed and aged under vacuum conditions of 0.06 MPa for 18 h to obtain the colloid.

[0049] The obtained colloid was dried at 150°C for 10 h, then removed, crushed, and washed to obtain the composite matrix.

[0050] The obtained composite matrix was mixed evenly with 1.8 g of silane coupling agent KH550, granulated, and then dried for 2 h at 110℃ to obtain the composite synergistic flame retardant.

[0051] The composite synergistic flame retardant of Example 4 was prepared by the preparation method of the composite synergistic flame retardant of Example 4. In the obtained composite synergistic flame retardant, antimony trioxide was loaded on the inner and outer surfaces of tubular kaolin in the form of nanoparticles. The particle size of the antimony trioxide nanoparticles was 50 nm. The mass ratio of tubular kaolin to antimony trioxide nanoparticles was 55:40. The mass ratio of the total mass of tubular kaolin and antimony trioxide nanoparticles to the mass of the coupling agent was 48:1.

[0052] Comparative Example 1 The preparation method of the synergistic flame retardant in Comparative Example 1 includes the following steps: Weigh 62.6 g of antimony chloride and dissolve it in 80 g of anhydrous ethanol to obtain solution A.

[0053] 50 g of tubular kaolin was weighed and evenly dispersed in 50 g of water to obtain solution B. The purity of the tubular kaolin was not less than 95%, and its fineness was not greater than 5000 mesh.

[0054] Slowly add the obtained solution A to the obtained solution B, stir and mix for 15 minutes to obtain solution C.

[0055] The pH was adjusted to 6 by slowly adding 5% dilute ammonia to solution C, and after stirring, the solution was vacuumed and aged under vacuum conditions of 0.08 MPa for 12 h to obtain the colloid.

[0056] The obtained colloid was dried at 120℃ for 10 h, then removed, crushed, and washed to obtain the composite matrix.

[0057] The obtained composite matrix was mixed evenly with 1.3 g of aluminate coupling agent DL411, granulated, and then dried at 110℃ for 1 h to obtain the synergistic flame retardant.

[0058] Comparative Example 2 The preparation method of the synergistic flame retardant in Comparative Example 2 includes the following steps: Weigh 62.6 g of antimony chloride and dissolve it in 80 g of anhydrous ethanol to obtain solution A.

[0059] Weigh 50 g of tubular kaolin and evenly disperse it in 50 g of water, adjusting the pH to 2.5 to obtain solution B. The tubular kaolin must have a purity of not less than 95% and a fineness of not more than 5000 mesh.

[0060] Slowly add the obtained solution A to the obtained solution B, stir and mix for 15 minutes to obtain solution C.

[0061] Slowly add 5% (w / w) dilute ammonia to solution C to adjust the pH to 6, stir, and age for 12 h to obtain the colloid.

[0062] The obtained colloid was dried at 120℃ for 10 h, then removed, crushed, and washed to obtain the composite matrix.

[0063] The obtained composite matrix was mixed evenly with 1.3 g of aluminate coupling agent DL411, granulated, and then dried at 110℃ for 1 h to obtain the synergistic flame retardant.

[0064] Comparative Example 3 The preparation method of the synergistic flame retardant in Comparative Example 3 includes the following steps: Weigh 50 g of tubular kaolin with a purity of not less than 95% and a fineness of not more than 5000 mesh.

[0065] Tubular kaolin was mixed evenly with 0.75 g of aluminate coupling agent DL411, granulated, and dried at 110℃ for 10 h to obtain a synergistic flame retardant.

[0066] Comparative Example 4 Comparative Example 4 used commercially available antimony trioxide as a synergistic flame retardant, provided by Pande (Shanghai) International Trading Co., Ltd.

[0067] Experimental Example 1 The composite synergistic flame retardants prepared in Examples 1-4 and the synergistic flame retardants prepared in Comparative Examples 1-4 were used to fill PVC composite materials, and the resulting PVC composite materials were subjected to performance tests to evaluate the flame retardant properties of the flame retardants obtained in Examples 1-4 and Comparative Examples 1-4 and their impact on the overall performance of PVC composite materials.

[0068] The PVC composite material comprises, by weight, the following raw materials: 50 parts PVC resin, 1.5 parts zinc borate, 25 parts dioctyl terephthalate (DOTP), 20 parts calcium carbonate, 2.5 parts kaolin, and 1 part flame retardant. The flame retardant is the composite synergistic flame retardant prepared in Examples 1-4 or the synergistic flame retardant prepared in Comparative Examples 1-4. After the above raw materials are mixed evenly, they are melt-blended in a torque rheometer to obtain the PVC composite material.

[0069] The obtained PVC composite material was tested according to standard GB / T 8815-2008, and the test results are shown in Table 1.

[0070] Table 1. Test results of flame retardant and mechanical properties of PVC composites prepared with different flame retardants.

[0071] Compared with the preparation method of the composite synergistic flame retardant in Example 1, Comparative Example 1 omitted the pH adjustment of solution B, resulting in an excessively rapid formation rate of antimony trioxide, which weakened its bonding with kaolin, increased crystal size, and uneven distribution on the kaolin surface, thus affecting the subsequent bonding strength with resin and flame retardant performance. Comparative Example 2 omitted the vacuum treatment, and solution C was only aged under normal pressure, making it difficult for the solution to penetrate into the kaolin tube, resulting in no antimony trioxide formation on the inner surface of the kaolin, thereby reducing the ratio of antimony trioxide to kaolin. As can be seen from Table 1, the mechanical properties and flame retardant properties of the PVC material prepared using the composite synergistic flame retardant of Example 1 are superior to those of Comparative Examples 1 and 2, indicating that the preparation method of the composite synergistic flame retardant of the present invention can improve the flame retardant performance and reinforcing effect of the composite synergistic flame retardant, thereby improving the flame retardant performance and mechanical properties of PVC composite materials.

[0072] As can be seen from Table 1, the mechanical properties and flame retardant properties of the PVC composite materials prepared using the composite synergistic flame retardants of Examples 1-4 are better than those of the PVC composite materials prepared using the single-component synergistic flame retardants of Comparative Examples 3-4, indicating that the composite synergistic flame retardant of the present invention has a better synergistic flame retardant effect and reinforcing effect.

Claims

1. A composite synergistic flame retardant, characterized in that, Antimony trioxide nanoparticles are loaded onto the inner and outer surfaces of tubular kaolin, and then modified with a coupling agent to obtain the product; the particle size of the antimony trioxide nanoparticles is 30-80 nm; the mass ratio of the tubular kaolin to the antimony trioxide nanoparticles is (50-60):(40-50), and the mass ratio of the total mass of the tubular kaolin and the antimony trioxide nanoparticles to the mass of the coupling agent is 100:(1-3).

2. The composite synergistic flame retardant according to claim 1, characterized in that, The tubular kaolin has a purity of not less than 95% and a fineness of not more than 5000 mesh.

3. The composite synergistic flame retardant according to claim 1, characterized in that, The coupling agent is one or more of titanate coupling agents, aluminate coupling agents, and organosilicon.

4. A method for preparing a composite synergistic flame retardant as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1: Dissolve antimony salt in the first solvent to obtain solution A, disperse tubular kaolin in the second solvent and adjust the pH to acidic to obtain solution B; S2: Add solution A obtained from S1 to solution B obtained from S1, add alkaline solution to adjust the pH to 5-8, stir, and then age under vacuum pressure to obtain a colloid; S3: After the colloid obtained in S2 is first dried, it is pulverized and washed to obtain the composite matrix; S4: Mix the composite matrix obtained in S3 with the coupling agent evenly, granulate, and perform a second drying to obtain the composite synergistic flame retardant.

5. The method for preparing the composite synergistic flame retardant according to claim 4, characterized in that, The antimony salt in S1 is one or more of antimony chloride, antimony nitrate, and antimony acetate; the mass ratio of the antimony salt to tubular kaolin is (62.6-105.6):

50.

6. The method for preparing the composite synergistic flame retardant according to claim 4, characterized in that, The mass ratio of the antimony salt to the first solvent in S1 is 1:(1-2), and the first solvent is ethanol; the mass ratio of the tubular kaolin to the second solvent is 1:(1-2), and the second solvent is water; adjusting the pH to acidity includes adjusting the pH to 1-3.

7. The method for preparing the composite synergistic flame retardant according to claim 4, characterized in that, The alkaline solution in S2 is dilute ammonia water, the vacuum degree is 0.05-0.1 MPa, and the pressure holding and aging time is 12-18 h.

8. The method for preparing the composite synergistic flame retardant according to claim 4, characterized in that, The first drying process in S3 is carried out at a temperature of 100–180°C for 8–16 hours.

9. The method for preparing the composite synergistic flame retardant according to claim 4, characterized in that, S4 The second drying temperature is 80-120°C, the time is 1-3 h, and the mass of the coupling agent is 1%-3% of the mass of the composite matrix.

10. The application of a composite synergistic flame retardant as described in any one of claims 1 to 3 in the preparation of flame retardant materials.

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