Glass fiber induced columnar aluminum diethylphosphinate flame retardant, its preparation method and application

Abstract

This invention relates to a glass fiber-induced columnar aluminum diethylphosphonate flame retardant, its preparation method, and its application, belonging to the field of flame retardant technology. The flame retardant comprises glass fibers and columnar aluminum diethylphosphonate grown on and around the surface of the glass fibers; wherein the content of the glass fibers is 0.01wt%~300wt% of the columnar aluminum diethylphosphonate; the average length of the columnar aluminum diethylphosphonate is 1.0μm~4.53μm; the 1% thermal weight loss temperature of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is >355℃, and the 5% thermal weight loss temperature is >415℃; the loose pack density of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is 0.58g / cm³. 3 ~1.22g / cm 3 This flame retardant, when used in engineering plastics, can improve their mechanical properties, increase flame retardant efficiency, reduce powder flying during mixing, and mitigate the problem of flame retardant precipitation.

Description

Technical Field

[0001] This invention relates to the field of flame retardant technology, and in particular to a glass fiber-induced columnar aluminum diethylphosphinate flame retardant, its preparation method, and its application. Background Technology

[0002] Aluminum diethylphosphonate (ADP), a novel and highly efficient phosphorus-based halogen-free flame retardant, has stood out due to its excellent comprehensive performance, becoming a core choice for flame retardant modification of engineering plastics. ADP boasts advantages such as high phosphorus content, excellent thermal stability, and environmental compliance. It does not release dioxins, halogens, or other toxic and harmful substances during combustion, and is widely used in engineering plastics such as polyamide (PA), polybutylene terephthalate (PBT), and polyethylene terephthalate (PET).

[0003] However, the aluminum diethylphosphonate currently used industrially is mostly amorphous with a loose crystal structure, resulting in low flame retardant efficiency. To achieve the desired flame retardant effect, a high proportion of flame retardant is often required, which not only increases production costs but may also affect the processing and mechanical properties of engineering plastics. Furthermore, in engineering plastics, to balance flame retardant and mechanical properties, aluminum diethylphosphonate is often compounded with glass fiber. However, when amorphous aluminum diethylphosphonate is directly mixed with glass fiber, problems such as powdering, flame retardant precipitation, and other issues arise due to poor interfacial compatibility and weak interparticle forces. Powdering affects the production environment and operator health, and also wastes flame retardant. Flame retardant precipitation leads to surface blooming, performance degradation, and even loss of flame retardant effect in engineering plastic products. In summary, when aluminum diethylphosphonate is used in engineering plastics, there are problems such as insufficient mechanical properties and flame retardant properties, easy mixing and powdering, and flame retardant precipitation. These problems seriously limit the application of aluminum diethylphosphonate in engineering plastics.

[0004] Therefore, it is necessary to develop a flame retardant that can solve the above-mentioned technical defects, so as to improve the mechanical properties and flame retardant properties of engineering plastics, reduce powder flying during mixing, and improve the problem of flame retardant precipitation. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a glass fiber-induced columnar aluminum diethylphosphinate flame retardant, its preparation method, and its application. When used in engineering plastics, this glass fiber-induced columnar aluminum diethylphosphinate flame retardant can improve the mechanical properties of the engineering plastics, increase flame retardant efficiency, reduce powder flying during mixing, and alleviate the problem of flame retardant precipitation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a glass fiber-induced columnar aluminum diethylphosphonic acid flame retardant, comprising glass fibers and columnar aluminum diethylphosphonic acid grown on and around the surface of the glass fibers; wherein the content of the glass fibers is 0.01wt%~300wt% of the columnar aluminum diethylphosphonic acid; the average length of the columnar aluminum diethylphosphonic acid is 1.0μm~4.53μm; the 1% thermal decomposition temperature of the glass fiber-induced columnar aluminum diethylphosphonic acid flame retardant is >355℃, and the 5% thermal decomposition temperature is >415℃; the loose pack density of the glass fiber-induced columnar aluminum diethylphosphonic acid flame retardant is 0.58g / cm³. 3 ~1.22g / cm 3 .

[0008] The glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention comprises glass fiber and columnar aluminum diethylphosphonate grown on and around the glass fiber. The glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention has the following characteristics: (1) The aluminum diethylphosphonate grown on and around the glass fiber has a columnar morphology, which can improve the compatibility of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant with the substrate when used in engineering plastics and reduce precipitation; (2) The regular crystal structure of the columnar aluminum diethylphosphonate gives the glass fiber-induced columnar aluminum diethylphosphonate flame retardant a higher thermal decomposition temperature, enabling it to adapt to more processing scenarios; (3) The glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention has a higher specific surface area, improving flame retardant performance and reducing the amount of flame retardant required when used in engineering plastics. (4) In the glass fiber-induced columnar aluminum diethyl phosphonate flame retardant of the present invention, aluminum diethyl phosphonate and glass fiber are both columnar structures. The columnar aluminum diethyl phosphonate can play a similar role to glass fiber, enhancing the mechanical strength of engineering plastics. (5) In the glass fiber-induced columnar aluminum diethyl phosphonate flame retardant of the present invention, the columnar aluminum diethyl phosphonate grows on the surface and around the glass fiber, that is, there is a certain degree of "composite" relationship between the columnar aluminum diethyl phosphonate and the glass fiber. This can reduce the problem of powder flying when the glass fiber-induced columnar aluminum diethyl phosphonate flame retardant is used in engineering plastics, while improving the efficiency of flame retardant use and reducing the amount of flame retardant used.

[0009] Further, the glass fiber content is 1wt%~200wt% of the columnar aluminum diethylphosphonate; the average length of the columnar aluminum diethylphosphonate is 1.80μm~3.85μm; the 1% thermal weight loss temperature of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is 356.0℃~379.2℃, and the 5% thermal weight loss temperature is 416.9℃~425.4℃; the loose pack density of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is 0.60g / cm³. 3 ~0.98g / cm 3 The glass fibers have a length of 1.5 mm to 4.5 mm and a diameter of 10 μm to 13 μm. As a preferred embodiment of the present invention, the glass fiber-induced columnar aluminum diethylphosphinate flame retardant having the above-mentioned preferred characteristics performs better when used in engineering plastics. Furthermore, it should be emphasized that the above-mentioned range of glass fiber length and diameter is only a preferred embodiment. The present invention can induce the formation of columnar aluminum diethylphosphinate using any glass fiber, and the present invention does not impose any particular limitation on the length, diameter, etc., of the glass fibers.

[0010] The present invention also provides a method for preparing the glass fiber-induced columnar aluminum diethylphosphinate flame retardant described above, comprising the following steps: (1) Raw material preparation: Prepare sodium diethylphosphonate aqueous solution, aluminum sulfate aqueous solution, and glass fiber; The concentration of sodium diethylphosphonate in the aqueous solution is 10wt%~30wt%; the concentration of aluminum sulfate in the aqueous solution is 10wt%~30wt%; the amounts of aluminum sulfate and sodium diethylphosphonate are such that the molar ratio of aluminum sulfate to sodium diethylphosphonate is (1.0~1.1):6; and the amount of glass fiber is 0.01wt%~300wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of aluminum sulfate and sodium diethylphosphonate. (2) Dispersion pretreatment: Sodium diethylphosphonate aqueous solution and glass fiber are mixed and stirred to obtain a uniform and stable dispersion; (3) Synthesis reaction: Add aluminum sulfate aqueous solution to the dispersion and react for 1h to 5h at a reaction temperature of 60℃~95℃ and a stirring speed of 300rpm~500rpm. After the reaction is completed, filter, wash and dry in sequence to obtain the glass fiber induced columnar aluminum diethylphosphinate flame retardant.

[0011] The method for preparing glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention, based on the preparation of aluminum diethylphosphonate using sodium diethylphosphonate and aluminum sulfate as raw materials, involves adding glass fiber. During the formation of aluminum diethylphosphonate, glass fiber is induced to form a columnar crystal structure on and around the surface of the glass fiber, thereby obtaining the glass fiber-induced columnar aluminum diethylphosphonate flame retardant. Specifically, in the preparation method of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention, in step (2), sodium diethylphosphonate is used as the precursor of aluminum diethylphosphonate, glass fiber is used as the induction template, and water is used as the dispersion medium. By mixing and stirring, sodium diethylphosphonate is uniformly dispersed on the surface and around the glass fiber, providing a reaction environment for subsequent induced growth. In step (3), by adding an aqueous aluminum sulfate solution to the dispersion, under the above reaction conditions, aluminum sulfate and sodium diethylphosphonate undergo a metathesis reaction. Under the induction of the glass fiber, regular columnar aluminum diethylphosphonate is generated on the surface and around the glass fiber, thereby obtaining the glass fiber-induced columnar aluminum diethylphosphonate flame retardant.

[0012] This invention reveals that the addition of glass fibers can induce the formation of columnar aluminum diethylphosphinate. The core mechanism is as follows: glass fibers act as a heterogeneous nucleation substrate, inducing one-dimensional preferential growth of aluminum diethylphosphinate crystals and restricting lateral growth through interfacial interactions, resulting in a columnar crystal structure. In conventional (glass fiber-free) aluminum diethylphosphinate synthesis systems, crystals mainly form through homogeneous nucleation. After random nucleation in the liquid phase, the precursor grows isotropically, easily forming random particles or aggregates, making it difficult to form a regular columnar morphology. However, this invention, by adding glass fibers and utilizing the abundant polar sites on the glass fiber surface, allows for the enrichment of the aluminum diethylphosphinate precursor (Et₂PO₂) through hydrogen bonding and electrostatic attraction within the aluminum diethylphosphinate synthesis system. - A1 3+ This provides a stable template for crystal nucleation, significantly reducing the nucleation activation energy and enabling heterogeneous nucleation. Heterogeneous nucleation increases the number of crystal nuclei, reduces their size, and ensures uniform distribution, effectively suppressing the formation and aggregation of large crystals. Simultaneously, the one-dimensional linear structure of the glass fibers and the directional arrangement of surface polar sites promote the one-dimensional extension of the diethylphosphinate crystals, forming uniformly sized and well-dispersed small columnar crystals. Furthermore, the local shearing during synthesis and the increased local supersaturation on the glass fiber surface further enhance the formation and stability of the small columnar morphology.

[0013] In the preparation method of this invention, in step (1), the concentration of sodium diethylphosphonate aqueous solution is controlled to be 10wt%~30wt%. This ratio range ensures that sodium diethylphosphonate reacts fully in step (3), while avoiding excessive water leading to low reaction concentration and decreased reaction efficiency, or insufficient water leading to uneven dispersion and poor induced growth effect. This invention also limits the concentration of the aluminum sulfate aqueous solution to 10wt%~30wt%. If the concentration is too high, the reaction will be too violent, and the generated aluminum diethylphosphonate crystals will have irregular morphology; if the concentration is too low, the reaction will be incomplete, affecting the yield and flame retardant performance. This invention controls the amount of aluminum sulfate aqueous solution and sodium diethylphosphonate aqueous solution to meet the following: the molar ratio of aluminum sulfate to sodium diethylphosphonate is (1.0~1.1):6, which can ensure the full conversion of sodium diethylphosphonate and complete crystal growth; at the same time, it avoids the generation of free impurities and improves the purity of the product.

[0014] In the preparation method of this invention, the amount of glass fiber used is 0.01wt% to 300wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of sodium diethylphosphonate and aluminum sulfate. Sodium diethylphosphonate and aluminum sulfate undergo a metathesis reaction to produce aluminum diethylphosphonate, and the reaction is complete. Therefore, theoretically, the phrase "the content of glass fiber is 0.01wt% to 300wt% of the columnar aluminum diethylphosphonate" in the glass fiber-induced columnar aluminum diethylphosphonate flame retardant of this invention refers to the content of glass fiber being 0.01wt% to 300wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of sodium diethylphosphonate and aluminum sulfate. Preferably, in step (1), the amount of glass fiber used is 1wt% to 200wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of sodium diethylphosphonate and aluminum sulfate.

[0015] Regarding the "columnar aluminum diethylphosphonate grown on and around the glass fiber" in the glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention, it can be understood that: during the preparation process, sodium diethylphosphonate and aluminum sulfate undergo a metathesis reaction, and under the induction of the glass fiber, columnar aluminum diethylphosphonate is first generated on the surface of the glass fiber; and as the reaction proceeds, the columnar aluminum diethylphosphonate can act as seed crystals to continue to induce the generation of columnar aluminum diethylphosphonate, thereby growing columnar aluminum diethylphosphonate on and around the glass fiber.

[0016] Furthermore, in step (3), an aqueous solution of aluminum sulfate is added to the dispersion at a uniform dripping rate of 1 mL / min to 10 mL / min. The above-mentioned dripping rate can ensure uniform crystal growth. Too slow a dripping rate will result in low efficiency, while too fast a dripping rate will easily lead to excessively rapid crystallization, which is not conducive to the formation of columnar crystals.

[0017] Furthermore, in step (3), deionized water is used for washing, and the conductivity of the filtrate after washing is <15 mS / cm. Washing removes impurities such as sodium sulfate generated during the reaction, thus preventing these impurities from affecting the performance of the flame retardant and the processing of engineering plastics.

[0018] Furthermore, in step (3), the drying temperature is 100℃~110℃, and the drying time is 3h~24h. Drying can effectively remove moisture from the flame retardant and avoid excessive moisture affecting the subsequent application of the flame retardant in engineering plastics.

[0019] The present invention also provides the application of the glass fiber-induced columnar aluminum diethylphosphinate flame retardant described above in engineering plastics. This flame retardant, as a halogen-free flame retardant, is applied in the field of flame retardant modification of engineering plastics.

[0020] By using the glass fiber-induced columnar aluminum diethylphosphonate flame retardant in engineering plastics, the mechanical properties of engineering plastics can be improved, the flame retardant efficiency can be increased, the amount of powder flying during mixing can be reduced, and the problem of flame retardant precipitation can be mitigated.

[0021] In the engineering plastics of the present invention, since the glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention contains a certain amount of glass fiber, when the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is used in engineering plastics, the addition of glass fiber can be reduced or even eliminated. Furthermore, the engineering plastics of the present invention can use the glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention alone, or can add at least one of the following synergistic flame retardants: nitrogen-based, silicon-based, phosphorus-based, phosphorus-nitrogen-based, aluminum hydroxide, or magnesium hydroxide, thereby obtaining engineering plastics with excellent flame retardancy. Preferably, the flame retardant of the present invention can be compounded with melamine polyphosphate and applied to PA6, PA66, or PBT systems.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: First, this invention is the first to utilize the heterogeneous induction effect of glass fibers to grow regular columnar aluminum diethylphosphonate crystals on and around the glass fiber surface, replacing the traditional irregular particulate structure. In the flame retardant prepared by this invention, the columnar aluminum diethylphosphonate grows on and around the glass fiber surface. When used in engineering plastics, this flame retardant not only imparts excellent flame retardant properties to the engineering plastics but also effectively transfers and disperses stress, compensating for the decline in mechanical properties of plastics caused by traditional flame retardants, and significantly improving the tensile strength, impact toughness, and other mechanical properties of the products. Second, in the flame retardant of this invention, the columnar aluminum diethylphosphonate growing on and around the glass fiber surface greatly improves the compatibility of the flame retardant with the plastic substrate, effectively inhibiting the migration and precipitation of the flame retardant, avoiding blooming and performance degradation on the product surface, extending the service life of engineering plastic products, and significantly increasing the bulk density of the flame retardant, effectively solving the problem of powder mixing and flying powder. Third, the flame retardant prepared by this invention has a thermal weight loss temperature of over 355°C at 1% and over 415°C at 5%, which is superior to conventional aluminum diethylphosphonate. It can withstand the high-temperature extrusion and injection molding processing conditions of engineering plastics and is suitable for more high-end engineering plastic processing scenarios. Attached Figure Description

[0023] Figure 1 SEM image of glass fiber-induced columnar aluminum diethylphosphinate flame retardant of Example 4; Figure 2 SEM image of glass fiber-induced columnar aluminum diethylphosphinate flame retardant of Example 5; Figure 3 SEM image of aluminum diethylphosphonate flame retardant in Comparative Example 1; Figure 4 TGA diagram of glass fiber-induced columnar aluminum diethylphosphinate flame retardant of Example 4; Figure 5 The image shows the TGA diagram of the glass fiber-induced columnar aluminum diethylphosphinate flame retardant of Example 5. Detailed Implementation

[0024] The present invention is further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from the conventional market. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are within the scope of protection claimed by the present invention.

[0025] Example 1 This embodiment provides a glass fiber-induced columnar aluminum diethylphosphonate flame retardant, which is prepared through the following specific steps: (1) Raw material preparation: Prepare sodium diethylphosphonate aqueous solution, aluminum sulfate aqueous solution, and glass fiber; The sodium diethylphosphonate aqueous solution contains 30 wt% sodium diethylphosphonate; the aluminum sulfate aqueous solution contains 30 wt% aluminum sulfate; and the amounts of aluminum sulfate and sodium diethylphosphonate aqueous solution satisfy the following conditions: the molar ratio of aluminum sulfate to sodium diethylphosphonate is 1.0:6; the glass fiber diameter is 13 μm, the length is 4.5 mm, and the amount of glass fiber used is 0.01 wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of aluminum sulfate and sodium diethylphosphonate. (2) Dispersion pretreatment: Sodium diethylphosphonate aqueous solution and glass fiber are mixed and stirred to obtain a uniform and stable dispersion; (3) Synthesis reaction: Aluminum sulfate aqueous solution was added dropwise to the dispersion at a rate of 1 mL / min. The reaction was carried out at a reaction temperature of 95℃ and a stirring speed of 500 rpm for 5 h. After the reaction was completed, the solution was filtered and washed. The conductivity of the filtrate after washing was <15 mS / cm. The solution was then dried at 100℃ for 24 h to obtain the glass fiber induced columnar aluminum diethylphosphinate flame retardant.

[0026] Example 2 This embodiment provides a glass fiber-induced columnar aluminum diethylphosphonate flame retardant, which is prepared through the following specific steps: (1) Raw material preparation: Prepare sodium diethylphosphonate aqueous solution, aluminum sulfate aqueous solution, and glass fiber; The sodium diethylphosphonate aqueous solution contains 30 wt% sodium diethylphosphonate; the aluminum sulfate aqueous solution contains 20 wt% aluminum sulfate; and the amounts of aluminum sulfate and sodium diethylphosphonate aqueous solution satisfy the following conditions: the molar ratio of aluminum sulfate to sodium diethylphosphonate is 1.1:6; the glass fiber diameter is 10 μm, the length is 1.5 mm, and the amount of glass fiber used is 1 wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of aluminum sulfate and sodium diethylphosphonate. (2) Dispersion pretreatment: Sodium diethylphosphonate aqueous solution and glass fiber are mixed and stirred to obtain a uniform and stable dispersion; (3) Synthesis reaction: Aluminum sulfate aqueous solution was added dropwise to the dispersion at a rate of 5 mL / min. The reaction was carried out at a reaction temperature of 60℃ and a stirring speed of 400 rpm for 1 h. After the reaction was completed, the solution was filtered and washed. The conductivity of the filtrate after washing was <15 mS / cm. The solution was then dried at 110℃ for 12 h to obtain the glass fiber induced columnar aluminum diethylphosphinate flame retardant.

[0027] Example 3 This embodiment provides a glass fiber-induced columnar aluminum diethylphosphonate flame retardant, which is prepared through the following specific steps: (1) Raw material preparation: Prepare sodium diethylphosphonate aqueous solution, aluminum sulfate aqueous solution, and glass fiber; The sodium diethylphosphonate aqueous solution contains 20 wt% sodium diethylphosphonate; the aluminum sulfate aqueous solution contains 20 wt% aluminum sulfate; and the amounts of aluminum sulfate and sodium diethylphosphonate aqueous solution satisfy the following conditions: the molar ratio of aluminum sulfate to sodium diethylphosphonate is 1.05:6; the glass fiber diameter is 11 μm, the length is 3 mm, and the amount of glass fiber used is 100 wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of aluminum sulfate and sodium diethylphosphonate. (2) Dispersion pretreatment: Sodium diethylphosphonate aqueous solution and glass fiber are mixed and stirred to obtain a uniform and stable dispersion; (3) Synthesis reaction: Aluminum sulfate aqueous solution was added dropwise to the dispersion at a rate of 5 mL / min. The reaction was carried out at a reaction temperature of 90℃ and a stirring speed of 300 rpm for 3 h. After the reaction was completed, the solution was filtered and washed. The conductivity of the filtrate after washing was <15 mS / cm. The solution was then dried at 105℃ for 12 h to obtain the glass fiber induced columnar aluminum diethylphosphinate flame retardant.

[0028] Example 4 This embodiment provides a glass fiber-induced columnar aluminum diethylphosphonate flame retardant, which is prepared through the following specific steps: (1) Raw material preparation: Prepare sodium diethylphosphonate aqueous solution, aluminum sulfate aqueous solution, and glass fiber; The sodium diethylphosphonate aqueous solution contains 10 wt% sodium diethylphosphonate; the aluminum sulfate aqueous solution contains 10 wt% aluminum sulfate; and the amounts of aluminum sulfate and sodium diethylphosphonate aqueous solution satisfy the following conditions: the molar ratio of aluminum sulfate to sodium diethylphosphonate is 1.05:6; the glass fiber diameter is 11 μm, the length is 3 mm, and the amount of glass fiber used is 200 wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of aluminum sulfate and sodium diethylphosphonate. (2) Dispersion pretreatment: Sodium diethylphosphonate aqueous solution and glass fiber are mixed and stirred to obtain a uniform and stable dispersion; (3) Synthesis reaction: Aluminum sulfate aqueous solution was added dropwise to the dispersion at a rate of 5 mL / min. The reaction was carried out at a reaction temperature of 90℃ and a stirring speed of 300 rpm for 3 h. After the reaction was completed, the solution was filtered and washed. The conductivity of the filtrate after washing was <15 mS / cm. The solution was then dried at 105℃ for 12 h to obtain the glass fiber induced columnar aluminum diethylphosphinate flame retardant.

[0029] Example 5 This embodiment provides a glass fiber-induced columnar aluminum diethylphosphonate flame retardant, which is prepared through the following specific steps: (1) Raw material preparation: Prepare sodium diethylphosphonate aqueous solution, aluminum sulfate aqueous solution, and glass fiber; The sodium diethylphosphonate aqueous solution contains 10 wt% sodium diethylphosphonate; the aluminum sulfate aqueous solution contains 10 wt% aluminum sulfate; and the amounts of aluminum sulfate and sodium diethylphosphonate aqueous solution satisfy the following conditions: the molar ratio of aluminum sulfate to sodium diethylphosphonate is 1.05:6; the glass fiber diameter is 11 μm, the length is 3 mm, and the amount of glass fiber used is 300 wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of aluminum sulfate and sodium diethylphosphonate. (2) Dispersion pretreatment: Sodium diethylphosphonate aqueous solution and glass fiber are mixed and stirred to obtain a uniform and stable dispersion; (3) Synthesis reaction: Aluminum sulfate aqueous solution was added dropwise to the dispersion at a rate of 10 mL / min. The reaction was carried out at a reaction temperature of 90℃ and a stirring speed of 300 rpm for 5 h. After the reaction was completed, the solution was filtered and washed. The conductivity of the filtrate after washing was <15 mS / cm. The solution was then dried at 105℃ for 12 h to obtain the glass fiber induced columnar aluminum diethylphosphinate flame retardant.

[0030] Comparative Example 1 This comparative example provides a diethylphosphonic acid aluminum flame retardant, which is prepared by the same method as that in Example 1, except that glass fiber is not used in this comparative example.

[0031] Physicochemical property characterization The physicochemical properties of the products obtained in Examples 1-5 and Comparative Example 1 were characterized respectively: Morphology: The morphology of the product was observed using a scanning electron microscope (SEM); Average length: The average crystal length of aluminum diethylphosphinate crystals in the SEM image is calculated by measuring the crystal length using the built-in SEM software and then averaging the result. Decomposition temperature (TGA): The decomposition temperature of the product at 1% and 5% thermal weight loss was tested according to GB / T 27761-2011 "Test method for weight loss and residual amount of thermogravimetric analyzer". Loose packing density: The loose packing density of the product was tested according to GB / T 1479.1-2011 "Determination of loose packing density of metal powders - Part 1: Funnel method".

[0032] Please refer to Table 1 for the results: Table 1. Comparison of physicochemical properties of products obtained from Comparative Example 1 and Examples 1-5

[0033] As shown in Table 1, the aluminum diethylphosphonate flame retardant of Comparative Example 1, without the addition of glass fiber to induce the formation of aluminum diethylphosphonate during preparation, yielded a mixed-morphology crystal containing needle-like, blocky, and plate-like forms. The average length of the aluminum diethylphosphonate crystals was small (0.54 μm), and they were isotropic and randomly packed, such as... Figure 3 As shown. The glass fiber-induced columnar aluminum diethylphosphonate flame retardants of Examples 1-5 of this invention are formed by adding glass fibers to induce the formation of columnar aluminum diethylphosphonate crystals on and around the glass fibers. Figure 1 The image shows a SEM image of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant of Example 4. The columnar aluminum diethylphosphonate grows on and around the glass fiber, and the average length of the aluminum diethylphosphonate crystals is 3.85 μm. Figure 2 The image shows a SEM image of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant of Example 5. The aluminum diethylphosphonate has a typical columnar morphology with an average crystal length of 4.53 μm.

[0034] Furthermore, as shown in Table 1, compared to Comparative Example 1, the TGA and loose density of the glass fiber-induced columnar aluminum diethylphosphinate flame retardants prepared in Examples 1-5 were improved due to the addition of glass fiber during the preparation process. As the amount of glass fiber (as a percentage of the theoretical yield of aluminum diethylphosphinate) increased from 0.01 wt% to 300 wt%, the 1% thermogravimetric temperature loss (compared to Comparative Example 1) of the glass fiber-induced columnar aluminum diethylphosphinate flame retardant increased by approximately 8°C to 33°C, and the 5% thermogravimetric temperature loss (compared to Comparative Example 1) increased by approximately 5°C to 13°C. Figure 4 The TGA graph shows the glass fiber-induced columnar aluminum diethylphosphonate flame retardant obtained in Example 4. The 1% and 5% thermal weight loss temperatures reached 379.2°C and 420.9°C, respectively. Figure 5 The TGA graph shows the glass fiber-induced columnar aluminum diethylphosphonate flame retardant obtained in Example 5. The 1% and 5% thermogravimetric losses (TGs) reached 376°C and 425.2°C, respectively. The glass fiber-induced columnar aluminum diethylphosphonate flame retardants prepared in Examples 1-5 of this invention exhibit improved temperature resistance due to the addition of glass fiber, making them more suitable for sample preparation in engineering plastics and for use on substrates with higher processing temperatures. Furthermore, the loose bulk density of the glass fiber-induced columnar aluminum diethylphosphonate flame retardants in Examples 1-5 of this invention increased from 0.51 g / cm³ initially (without glass fiber, i.e., Comparative Example 1). 3 It can be increased to 1.22 g / cm³. 3This invention effectively reduces losses such as fly powder during product preparation and improves the efficiency of flame retardant use and flame retardancy. These two results can be attributed to the fact that the glass fiber-induced columnar aluminum diethylphosphonate flame retardant prepared in this invention grows on and around the glass fiber, meaning that there is a certain degree of "composite" relationship between the columnar aluminum diethylphosphonate and the glass fiber. This effectively reduces problems such as fly powder during mixing when the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is used in engineering plastics.

[0035] Application performance testing The glass fiber-induced columnar aluminum diethylphosphonate flame retardants of Examples 1-5 and the aluminum diethylphosphonate flame retardant of Comparative Example 1 were used for flame retardancy of PBT to prepare engineering plastics with PBT as the base material. Specifically: The ingredients were prepared according to the formulations in Table 2, and engineering plastics 1' and 1-5 were produced using conventional processes. Specifically, the aluminum diethylphosphinate flame retardant of Comparative Example 1 was used to prepare engineering plastic 1', and the glass fiber-induced columnar aluminum diethylphosphinate flame retardants of Examples 1-5 were used to prepare engineering plastics 1-5, respectively. The total weight of each engineering plastic 1' and engineering plastics 1-5 was set to 3000g; the specific formulations are shown in Table 2.

[0036] In the glass fiber-induced columnar aluminum diethylphosphonate flame retardants of Examples 1-5, the amount of glass fiber used accounts for 0.01wt%, 1.00wt%, 100.00wt%, 200.00wt%, and 300.00wt% of the theoretical yield of aluminum diethylphosphonate, respectively. Referring to Table 2, in engineering plastics 1-5, in addition to the glass fiber-induced columnar aluminum diethylphosphonate flame retardants of Examples 1-5, 900g, 895g, 450g, 0g, and 0g of glass fiber are added respectively according to the corresponding formulations; in engineering plastic 1', in addition to the aluminum diethylphosphonate flame retardant of Comparative Example 1, 900g of glass fiber is added.

[0037] After preparing engineering plastic 1' and engineering plastics 1~5, the following performance tests were conducted, and the test results are shown in Table 2.

[0038] Tensile strength: According to ISO 527 standard for testing plastics under tensile stress, the testing rate is 5.0 mm / min; Flexural strength and flexural modulus: according to ISO 178 standard for testing the flexural properties of plastics, rate: 2.0 mm / min; Impact strength: According to ISO 180 standard for the determination of impact strength of simply supported plastic beams, the sample thickness is 4 mm; Flame retardant performance: UL-94, 1.6mm; Precipitation test: The engineering plastic was placed at 85℃ and 85%RH for 1000h, and the precipitation on the surface of the engineering plastic was observed.

[0039] Table 2 Test results of the formulation and application performance

[0040] As shown in Table 2, engineering plastic 1', which uses aluminum diethylphosphonate and glass fiber alone (as in Comparative Example 1), exhibits the worst mechanical and flame-retardant properties and suffers from flame retardant precipitation. Engineering plastics 1-5, which use glass fiber-induced columnar aluminum diethylphosphonate flame retardants from Examples 1-5 respectively, demonstrate superior mechanical, flame-retardant, and anti-precipitation properties compared to engineering plastic 1'. This is because, compared to the mixed-morphology aluminum diethylphosphonate in Comparative Example 1, the columnar aluminum diethylphosphonate in Examples 1-5 grows on and around the glass fiber, effectively compensating for the decline in mechanical properties caused by traditional flame retardants while imparting excellent flame-retardant properties to the engineering plastics. This significantly improves tensile strength, impact toughness, and other mechanical properties, while also greatly enhancing the compatibility of the flame retardant with the plastic substrate and effectively inhibiting flame retardant migration and precipitation.

[0041] The performance results of engineering plastics 1-4 show that, under the condition that the total amount of aluminum diethyl phosphonate and the total amount of glass fiber in the engineering plastics are constant (in engineering plastics 1-4, the total amount of aluminum diethyl phosphonate is 450g, and the total amount of glass fiber is 900g whether or not it is added), the higher the proportion of glass fiber in the glass fiber-induced columnar aluminum diethyl phosphonate flame retardant, the better the application performance. The glass fiber-induced columnar aluminum diethyl phosphonate flame retardant prepared according to a mass ratio of glass fiber to theoretical yield of aluminum diethyl phosphonate of 200wt% (Example 4) has the best mechanical and flame retardant properties. This is because, in the flame retardant structure of the present invention, columnar aluminum diethyl phosphonate grows on and around the glass fiber surface. When the amount of glass fiber is sufficient and no additional glass fiber is needed, the compatibility with the substrate can be further improved, thereby achieving better mechanical properties.

[0042] The content of aluminum diethylphosphonate in engineering plastic 5 is lower than that in engineering plastic 4. A comparison of the performance results of engineering plastic 4 and engineering plastic 5 shows that the flame retardant performance of engineering plastic 5 is still at a level comparable to that of Example 4. This indicates that the glass fiber-induced columnar aluminum diethylphosphonate flame retardant of the present invention can maintain good flame retardant performance in engineering plastics even with a reduction in the amount of aluminum diethylphosphonate.

[0043] Furthermore, the content of aluminum diethylphosphonic acid in engineering plastic 5 is lower than that in engineering plastic 1'. A comparison of the performance results of engineering plastic 5 and engineering plastic 1' shows that engineering plastic 5 still maintains good mechanical and flame-retardant properties, both superior to those of engineering plastic 1'. This also indicates that using the glass fiber-induced columnar aluminum diethylphosphonic acid flame retardant of the present invention in engineering plastics can maintain good flame-retardant properties even with a reduced amount of aluminum diethylphosphonic acid.

[0044] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A glass fiber-induced columnar aluminum diethylphosphinate flame retardant, characterized in that, The flame retardant comprises glass fibers and columnar aluminum diethylphosphonate grown on and around the surface of the glass fibers; wherein the content of the glass fibers is 0.01wt% to 300wt% of the columnar aluminum diethylphosphonate; the average length of the columnar aluminum diethylphosphonate is 1.0μm to 4.53μm; the 1% thermal weight loss temperature of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is >355℃, and the 5% thermal weight loss temperature is >415℃; the loose pack density of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is 0.58g / cm³. 3 ~1.22g / cm 3 .

2. The glass fiber-induced columnar aluminum diethylphosphinate flame retardant according to claim 1, characterized in that, The glass fiber content is 1wt%~200wt% of the columnar aluminum diethylphosphonate; the average length of the columnar aluminum diethylphosphonate is 1.80μm~3.85μm; the 1% thermal weight loss temperature of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is 356.0℃~379.2℃, and the 5% thermal weight loss temperature is 416.9℃~425.4℃; the loose pack density of the glass fiber-induced columnar aluminum diethylphosphonate flame retardant is 0.60g / cm³. 3 ~0.98g / cm 3 The glass fiber has a length of 1.5mm to 4.5mm and a diameter of 10μm to 13μm.

3. A method for preparing the glass fiber-induced columnar aluminum diethylphosphinate flame retardant according to any one of claims 1 to 2, characterized in that, Includes the following steps: (1) Raw material preparation: Prepare sodium diethylphosphonate aqueous solution, aluminum sulfate aqueous solution, and glass fiber; The concentration of sodium diethylphosphonate in the aqueous solution is 10wt%~30wt%; the concentration of aluminum sulfate in the aqueous solution is 10wt%~30wt%; the amounts of aluminum sulfate and sodium diethylphosphonate are such that the molar ratio of aluminum sulfate to sodium diethylphosphonate is (1.0~1.1):6; and the amount of glass fiber is 0.01wt%~300wt% of the theoretical yield of aluminum diethylphosphonate produced by the reaction of sodium diethylphosphonate and aluminum sulfate. (2) Dispersion pretreatment: Sodium diethylphosphonate aqueous solution and glass fiber are mixed and stirred to obtain a uniform and stable dispersion; (3) Synthesis reaction: Add aluminum sulfate aqueous solution to the dispersion and react for 1h to 5h at a reaction temperature of 60℃~95℃ and a stirring speed of 300rpm~500rpm. After the reaction is completed, filter, wash and dry in sequence to obtain the glass fiber induced columnar aluminum diethylphosphinate flame retardant.

4. The method for preparing the glass fiber-induced columnar aluminum diethylphosphinate flame retardant according to claim 3, characterized in that, In step (1), the amount of glass fiber used is 1wt% to 200wt% of the theoretical yield of aluminum diethylphosphonate produced after the reaction of sodium diethylphosphonate and aluminum sulfate.

5. The method for preparing the glass fiber-induced columnar aluminum diethylphosphinate flame retardant according to claim 3, characterized in that, In step (3), aluminum sulfate aqueous solution is added to the dispersion by uniform dripping at a rate of 1 mL / min to 10 mL / min.

6. The method for preparing the glass fiber-induced columnar aluminum diethylphosphinate flame retardant according to claim 3, characterized in that, In step (3), deionized water is used for washing, and the conductivity of the filtrate after washing is <15mS / cm.

7. The method for preparing the glass fiber-induced columnar aluminum diethylphosphinate flame retardant according to claim 3, characterized in that, In step (3), the drying temperature is 100℃~110℃ and the drying time is 3h~24h.

8. The application of the glass fiber-induced columnar aluminum diethylphosphinate flame retardant according to any one of claims 1 to 2 in engineering plastics, characterized in that: This flame retardant, as a halogen-free flame retardant, is used in the field of flame retardant modification of engineering plastics.

9. The application of the glass fiber-induced columnar aluminum diethylphosphinate flame retardant according to claim 8 in engineering plastics, characterized in that: This flame retardant is compounded with melamine polyphosphate and applied to PA6, PA66 or PBT systems.

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