High-strength polyester fiber and preparation method thereof

Abstract

The invention relates to the technical field of polyester fibers, and discloses a high-strength polyester fiber and a preparation method thereof.The preparation method comprises the following preparation steps that polyester chips are dried and then mixed and stirred with a composite flame-retardant material, and a blended material is obtained; and carrying out melt spinning, drafting and winding molding on the blended material to obtain the high-strength polyester fiber. In the composite flame-retardant material, lanthanum phenylphosphonate with a layered structure coats the upper and lower surfaces of alpha-zirconium phosphate nanosheets, an effective barrier layer can be formed in the polyester fiber, the combustion process is slowed down, and the composite layered material can absorb external stress and improve the mechanical property of the polyester fiber; in the composite flame-retardant material, the potassium titanate whiskers loaded with the porous carbon adsorb the phosphonitrilic chloride trimer derivative and the carboxymethyl cellulose, migration and precipitation of the flame-retardant material are avoided, and the potassium titanate whiskers have high length-diameter ratio, are disorderly distributed in the polyester fiber and show excellent toughness, so that the mechanical property of the polyester fiber is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyester fibers, in particular to a high-strength polyester fiber and a preparation method thereof. BACKGROUND

[0002] Polyester fiber, also known as polyester, is a synthetic fiber made from organic diacid and diol through chemical polycondensation, which belongs to a kind of high molecular compound. It has excellent wrinkle resistance and shape retention. The clothes made of polyester fiber are not easy to wrinkle during wearing, and can maintain the original shape of the clothes. In addition, polyester fiber has high strength and elastic recovery ability, so that the woven fabric is firm and durable, and can quickly recover to its original shape. In addition, polyester fiber also has the characteristics of anti-wear and no hair sticking, etc., which makes the fabric look more tidy, and is widely used in the fields of textile and garment manufacturing, etc.

[0003] The limiting oxygen index of polyester fiber is low, only 21%, which belongs to flammable material and cannot meet the fireproof needs in daily life. Therefore, it is necessary to endow polyester fiber with flame retardant property. More and more researchers pay attention to the flame-retardant dripping modification of polyester fiber. The polyester fiber prepared by blending inorganic flame-retardant materials, organic flame-retardant materials and polyester chips has excellent flame-retardant property. However, the inorganic flame-retardant materials are easy to agglomerate, and the small molecule flame-retardant materials have poor thermal stability and are easy to migrate and precipitate, which leads to the decrease of flame-retardant property. In addition, the inorganic agglomerates will become stress concentration points, which reduces the mechanical strength of polyester fiber material. How to ensure the strength of polyester fiber and improve the flame-retardant effect is a problem to be solved at present. SUMMARY

[0004] The present application provides a high-strength polyester fiber and a preparation method thereof, which solves the problems of insufficient flame retardance and mechanical strength of the existing polyester fiber.

[0005] The technical scheme of the present application is as follows: A preparation method of a high-strength polyester fiber, comprising the following preparation steps: S1. After drying the polyester chips at 100-120℃ for 1-2h, mix them with a composite flame-retardant material, stir at 500-600r / min for 30-40min to obtain a blended material; S2. The blended material is melt-spun, drawn and wound to form a high-strength polyester fiber; The composite flame-retardant material is obtained by mixing and reacting a composite layered material, modified potassium titanate whiskers and tetraethyl orthosilicate, and then freeze-drying; The composite layered material is obtained by mixing and reacting polydopamine surface modified alpha-zirconium phosphate nanosheets, lanthanum chloride and phenyl phosphonic acid; The modified potassium titanate whiskers are obtained by mixing and calcining potassium titanate whiskers and glucose, and then mixing and reacting with carboxymethyl cellulose and hexachlorocyclotriphosphazene derivative.

[0006] Further, the mass ratio of the polyester chip and the composite flame-retardant material is (100-120):(20-25).

[0007] Further, the melt spinning is performed on a double-screw high-speed composite spinning machine, the spinning speed is 800-1200 m / min, and the spinning machine temperature is 260-290℃.

[0008] Further, the drawing is performed on a parallel drawing machine, the temperature is 60-90℃, the drawing speed is 300-400 m / min, and the drawing multiple is 5.5-6.5.

[0009] Further, the composite flame-retardant material is prepared by the following steps: A1. The alpha-zirconium phosphate nanosheet is added to the Tris-HCl buffer solution, stirred uniformly, dopamine is added, stirred and reacted for 3-5 h, filtered, washed, and dried to obtain the polydopamine modified alpha-zirconium phosphate nanosheet; A2. The polydopamine modified alpha-zirconium phosphate nanosheet is added to the deionized water, stirred uniformly, lanthanum chloride and ethanol are added, stirred for 30-40 min, phenyl phosphonic acid is added, stirred uniformly, placed in a reaction kettle, reacted at 100-120℃ for 10-12 h, cooled to room temperature, filtered, washed, and dried to obtain the composite layered material; A3. Glucose is added to ethanol, stirred uniformly, potassium titanate whiskers are added, stirred and mixed at 80-90℃ for 30-40 min, placed in a tube furnace, potassium hydroxide solution is added, nitrogen is introduced, carbonized at 800-900℃ for 3-5 h, cooled to room temperature, taken out, washed, and dried to obtain the porous carbon loaded potassium titanate whisker; A4. Hexachlorocyclotriphosphazene, p-hydroxybenzaldehyde, and potassium carbonate are added to tetrahydrofuran, argon is introduced, stirred and reacted for 3-5 h, tetrahydrofuran is distilled out under reduced pressure, placed in deionized water, stirred until a precipitate is formed, filtered to obtain the precipitate, the precipitate is washed and dried to obtain the hexachlorocyclotriphosphazene derivative; A5. The hexachlorocyclotriphosphazene derivative is added to tetrahydrofuran to obtain solution A, carboxymethyl cellulose is added to deionized water, stirred uniformly to obtain solution B, solution A and solution B are mixed, the porous carbon loaded potassium titanate whisker is added, tetrahydrofuran is removed by distillation under reduced pressure, and dried to obtain the modified potassium titanate whisker; A6. The modified potassium titanate whisker and the composite layered material are added to ethanol and deionized water, stirred uniformly, ammonia water is added to adjust the pH, tetraethyl orthosilicate is added, stirred and reacted at 40-50℃ for 1-2 h, cooled to room temperature, and freeze-dried to obtain the composite flame-retardant material.

[0010] Further, in the above A1 reaction process, dopamine can self-polymerize on the surface of the alpha-zirconium phosphate nanosheet to form polydopamine in the Tris-HCl buffer solution, forming an alpha-zirconium phosphate nanosheet surface modified with polydopamine, so that the alpha-zirconium phosphate nanosheet has excellent adhesion, which is beneficial to the synthesis of layered lanthanum phenylphosphonate on the alpha-zirconium phosphate nanosheet.

[0011] Further, in the above A2 reaction process, the surface of the polydopamine modified alpha-zirconium phosphate nanosheet contains a large number of phenolic hydroxyl structures, which can combine with lanthanum ions in lanthanum chloride, so that the lanthanum ions are adsorbed on the surface of the polydopamine modified alpha-zirconium phosphate nanosheet, and the lanthanum element can form a ligand with the phosphonic acid group in the phenylphosphonic acid and bond with the phosphorus atom, so that the phenylphosphonic acid is uniformly attached to the upper and lower surfaces of the nanosheet. After hydrothermal reaction, layered lanthanum phenylphosphonate is formed on the upper and lower surfaces of the alpha-zirconium phosphate nanosheet, forming a composite layered material.

[0012] Further, in the above A3 reaction process, glucose is dissolved in ethanol and coated on the surface of potassium titanate whiskers, and after high-temperature carbonization, glucose is decomposed by heat to form a dense carbon layer, and the activator potassium hydroxide molecules are decomposed to form pores on the surface of the dense carbon layer, thereby synthesizing porous carbon on the surface of the potassium titanate whisker and obtaining a porous carbon loaded potassium titanate whisker.

[0013] Further, in the above A4 reaction process, in the organic solvent tetrahydrofuran, potassium carbonate acts as a catalyst to promote the reaction of hexachlorocyclotriphosphazene and p-hydroxybenzaldehyde, so that p-hydroxybenzaldehyde is grafted on the hexachlorocyclotriphosphazene molecule to form a hexachlorocyclotriphosphazene derivative.

[0014] Further, in the above A5 reaction process, carboxymethyl cellulose is mixed with the hexachlorocyclotriphosphazene derivative. Carboxymethyl cellulose contains more oxygen-containing functional groups, and the porous carbon loaded potassium titanate whisker has adsorption properties, which can adsorb carboxymethyl cellulose and hexachlorocyclotriphosphazene derivative on the surface of the porous carbon loaded potassium titanate whisker to obtain modified potassium titanate whisker.

[0015] Further, in the above A6 reaction process, tetraethyl orthosilicate is hydrolyzed to form a silica aerogel structure, and the surface of the composite layered lanthanum phenylphosphonate and the modified potassium titanate whisker contains a large number of hydroxyl structures, which can combine with the silicon hydroxyl groups produced by the hydrolysis of tetraethyl orthosilicate, so that the composite layered lanthanum phenylphosphonate and the modified potassium titanate whisker are embedded in the silica aerogel structure to obtain a composite flame retardant material.

[0016] Further, in step A1, the amount ratio of the alpha-zirconium phosphate nanosheet, Tris-HCl buffer solution and dopamine is (4.2-4.4) g:(40-50) mL:(0.3-0.5) g.

[0017] Further, in step A2, the polydopamine modified zirconium alpha-phosphate nanosheet, deionized water, lanthanum chloride, ethanol and phenyl phosphonic acid are used in a ratio of (5-6) g:(45-55) mL:(1.5-1.9) g:(45-55) mL:(2-3) g.

[0018] Further, in step A3, the glucose, ethanol, potassium titanate whisker and potassium hydroxide solution are used in a ratio of (4-5) g:(45-55) mL:(10-11) g:(4-6) mL.

[0019] Further, in step A4, the hexachlorocyclotriphosphazene, p-hydroxybenzaldehyde, potassium carbonate, tetrahydrofuran and deionized water are used in a ratio of (1-2) g:(2-3) g:(0.4-0.6) g:(35-45) mL:(70-90) mL.

[0020] Further, in step A5, the hexachlorocyclotriphosphazene derivative, tetrahydrofuran, carboxymethyl cellulose, deionized water and porous carbon loaded potassium titanate whisker are used in a ratio of (2-3) g:(25-35) mL:(1-2) g:(25-35) mL:(7-8) g.

[0021] Further, in step A6, the modified potassium titanate whisker, composite layered material, ethanol, deionized water and tetraethyl orthosilicate are used in a ratio of (2.2-2.4) g:(1.6-1.8) g:(45-55) mL:(10-20) mL:(8-12) g.

[0022] Further, the potassium titanate whisker has a diameter of 10-15 nm and a length of 1.5-2 μm.

[0023] The present application has the following beneficial effects: (1) In the technical scheme of the present application, a large number of proton acid sites are exposed on the nanosheet layer of the alpha-zirconium phosphate nanosheet during the combustion process, which catalyzes the cross-linking of polyester chains in the polyester fiber to form residual carbon, thereby having flame retardant performance. As a rigid nanosheet, the alpha-zirconium phosphate nanosheet can improve the mechanical properties of the polyester fiber by transferring stress. The layered structure of the phenyl phosphonic acid lanthanum is coated on the upper and lower surfaces of the alpha-zirconium phosphate nanosheet to form a composite layered material. On the one hand, the composite layered material forms an effective barrier layer in the polyester fiber, which can prevent the transmission of oxygen and heat, thereby slowing down the combustion process. In addition, the phenyl phosphonic acid lanthanum in the composite layered material can catalyze the rapid cross-linking of polyester molecular chains in the polyester fiber into carbon during the combustion process, thereby forming a more dense carbon layer and improving the flame retardant performance. On the other hand, the composite layered material can absorb external stress, further improving the mechanical properties of the polyester fiber. In addition, the layered structure of the phenyl phosphonic acid lanthanum coated on the alpha-zirconium phosphate nanosheet further strengthens the density and gas barrier performance of the carbon layer, significantly enhancing the barrier combustion effect.

[0024] (2) In the technical scheme of the present application, porous carbon is synthesized on the surface of potassium titanate whiskers to form a concave-convex layer, increase the surface roughness, and improve the contact area between the potassium titanate whiskers and the polyester fiber matrix. In addition, the synthesized porous carbon has a porous structure and exhibits excellent heat resistance, thereby improving the heat resistance of the polyester fiber. Furthermore, the potassium titanate whiskers have a high aspect ratio and are randomly distributed in the polyester fiber, showing excellent toughness and improving the mechanical properties of the polyester fiber. The p-hydroxybenzaldehyde is grafted on the hexachlorocyclotriphosphazene molecule, providing a large number of reactive functional groups and rigid benzene ring structures for the p-hydroxybenzaldehyde, which acts on the polyester fiber to improve its mechanical strength. In addition, the hexachlorocyclotriphosphazene contains phosphorus and nitrogen elements, which can form a phosphorus-nitrogen synergistic system during the combustion process. This system can deposit inorganic solid phase on the surface of the polyester fiber, preventing combustion.

[0025] (3) In the technical scheme of the present application, the hexachlorocyclotriphosphazene derivative is adsorbed on the surface of the porous carbon-loaded potassium titanate whisker. The porous carbon-loaded potassium titanate whisker serves as a carrier for the hexachlorocyclotriphosphazene derivative and carboxymethyl cellulose, preventing the migration and precipitation of the flame retardant material. In addition, the carboxymethyl cellulose provides a carbon source, which provides a large amount of carbon layer during the combustion process. The composite layered lanthanum phenyl phosphonate and modified potassium titanate whisker are embedded into the silica aerogel structure, increasing the cross-linking density of the silica aerogel and enhancing the mechanical properties. In addition, the formed silica aerogel has a porous structure and can adsorb molten polyester chips, allowing the silica aerogel to be uniformly pulverized in the polyester fiber, thereby improving the mechanical properties and flame retardant properties of the polyester fiber. DETAILED DESCRIPTION

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] The raw materials used in the embodiments of this invention are shown below, and all reagents used are analytical grade.

[0028] Polyester chips, item number HH7110OKPUYA, Dongguan Ruiqian New Materials Co., Ltd.

[0029] Potassium titanate whiskers have a diameter of 0.3 μm and a diameter-to-length ratio of 5 μm. (Hubei Yamaide Biomedical Co., Ltd.)

[0030] α-Zirconium phosphate nanosheets are prepared by the following steps: 4 g of zirconium oxychloride octahydrate was added to 40 mL of 6 M phosphoric acid solution, stirred until homogeneous, placed in a reaction vessel, heated at 200°C for 5 h, cooled to room temperature, and centrifuged at 5000 r / min for 10 min to separate the white precipitate. The precipitate was washed 5 times with deionized water and dried in a 70°C oven for 20 min to obtain α-zirconium phosphate nanosheets. Example

[0031] A method for preparing high-strength polyester fiber includes the following preparation steps: S1. After drying the polyester chips at 100℃ for 1 hour, mix them with the composite flame retardant material and stir at 500 r / min for 30 minutes to obtain the blend. S2. The blended material is melt-spun, drawn, and wound to form high-strength polyester fibers; The mass ratio of polyester chips to composite flame-retardant materials is 100:20. Melt spinning was carried out on a twin-screw high-speed composite spinning machine at a spinning speed of 800 m / min and a spinning machine temperature of 260℃. The drawing was performed on a parallel drawing machine at a temperature of 60℃, a drawing speed of 300m / min, and a drawing ratio of 5.5.

[0032] The composite flame-retardant material is prepared by the following steps: A1. Add 4.2g of α-zirconium phosphate nanosheets to 40mL of Tris-HCl buffer solution with pH 8.5, stir well, add 0.3g of dopamine, stir for 3h, filter, wash 3 times with deionized water, and dry in an oven at 70℃ for 10min to obtain polydopamine-modified α-zirconium phosphate nanosheets. A2. 5 g of polydopamine modified zirconium alpha-phosphate nanosheet was added to 45 mL of deionized water, stirred uniformly, 1.5 g of lanthanum chloride and 45 mL of ethanol were added, stirred for 30 min, 2 g of phenyl phosphonic acid was added, stirred uniformly, placed in a reaction kettle, reacted at 100℃ for 10 h, cooled to room temperature, filtered, washed with deionized water 5 times, dried in an oven at 80℃ for 15 min, to obtain a composite layered material; A3. 4 g of glucose was added to 45 mL of ethanol, stirred uniformly, 10 g of potassium titanate whisker was added, stirred and mixed at 80℃ for 30 min, placed in a tube furnace, 5 mL of 52.8% mass fraction potassium hydroxide solution was added, nitrogen was introduced, carbonized at 800℃ for 3 h, cooled to room temperature, taken out, washed with deionized water 3 times, dried in an oven at 70℃ for 10 min, to obtain a porous carbon loaded potassium titanate whisker; A4. 1 g of hexachlorocyclotriphosphazene, 2 g of p-hydroxybenzaldehyde, and 0.4 g of potassium carbonate were added to 35 mL of tetrahydrofuran, argon was introduced, and the reaction was stirred for 3 h. After the tetrahydrofuran was distilled off under reduced pressure at 40℃, it was placed in 70 mL of deionized water and stirred until a precipitate was formed. The precipitate was filtered to obtain a precipitate, which was washed with deionized water 3 times and dried in an oven at 50℃ for 10 min to obtain a hexachlorocyclotriphosphazene derivative; A5. 2 g of hexachlorocyclotriphosphazene derivative was added to 25 mL of tetrahydrofuran to obtain solution A. 1 g of carboxymethyl cellulose was added to 25 mL of deionized water and stirred uniformly to obtain solution B. Solution A and solution B were mixed, 7 g of porous carbon loaded potassium titanate whisker was added, and the tetrahydrofuran solvent was removed by vacuum distillation at 45℃. The mixture was dried in an oven at 105℃ for 10 min to remove water to obtain modified potassium titanate whisker; A6. 2.2 g of modified potassium titanate whisker and 1.6 g of composite layered material were added to 45 mL of ethanol and 10 mL of deionized water, stirred uniformly, 8 g of tetraethyl orthosilicate was added, and the pH was adjusted to 8.5 by adding 45% mass fraction ammonia water. The mixture was stirred and reacted at 40℃ for 1 h, cooled to room temperature, and freeze-dried at -20℃ for 20 h to obtain a composite flame retardant material. Embodiment

[0033] A method for preparing a high-strength polyester fiber, comprising the following preparation steps: S1. The polyester chip was dried at 110℃ for 1.5 h, then mixed with the composite flame retardant material, stirred at 550 r / min for 35 min to obtain a blend; S2. The blend was melt-spun, drawn, and wound to form a high-strength polyester fiber; Wherein the mass ratio of polyester chip to composite flame retardant material is 110:23; The melt spinning is performed on a double-screw high-speed composite spinning machine, the spinning speed is 1000 m / min, and the spinning machine temperature is 270 DEG C; The drawing is performed on a parallel drawing machine, the temperature is 75 DEG C, the drawing speed is 350 m / min, and the drawing multiple is 6.

[0034] The composite flame-retardant material is prepared by the following steps: A1. 4.3 g of α-zirconium phosphate nanosheets is added to 45 mL of Tris-HCl buffer with a pH of 8.5, stirred uniformly, 0.4 g of dopamine is added, stirred for 4 h, filtered, washed with deionized water for 3 times, dried in a 70 DEG C oven for 10 min, and α-zirconium phosphate nanosheets modified by polydopamine is obtained; A2. 5.4 g of α-zirconium phosphate nanosheets modified by polydopamine is added to 50 mL of deionized water, stirred uniformly, 1.7 g of lanthanum chloride and 50 mL of ethanol are added, stirred and mixed for 35 min, 2.5 g of phenyl phosphonic acid is added, stirred uniformly, placed in a reaction kettle, reacted at 110 DEG C for 11 h, cooled to room temperature, filtered, washed with deionized water for 5 times, and dried in an 80 DEG C oven for 15 min to obtain a composite layered material; A3. 4.5 g of glucose is added to 50 mL of ethanol, stirred uniformly, 10.5 g of potassium titanate whiskers is added, stirred and mixed at 85 DEG C for 35 min, placed in a tube furnace, 5 mL of 52.8% potassium hydroxide solution is added, nitrogen is introduced, carbonized at 850 DEG C for 4 h, cooled to room temperature, taken out, washed with deionized water for 3 times, and dried in a 70 DEG C oven for 10 min to obtain potassium titanate whiskers loaded with porous carbon; A4. 1.5 g of hexachlorocyclotriphosphazene, 2.5 g of p-hydroxybenzaldehyde, and 0.5 g of potassium carbonate are added to 40 mL of tetrahydrofuran, argon is introduced, stirred and reacted for 4 h, tetrahydrofuran is distilled out under reduced pressure at 40 DEG C, placed in 80 mL of deionized water, stirred until a precipitate is formed, left to stand, filtered to obtain the precipitate, the precipitate is washed with deionized water for 3 times, and dried in a 50 DEG C oven for 10 min to obtain a hexachlorocyclotriphosphazene derivative; A5. 2.6 g of the hexachlorocyclotriphosphazene derivative is added to 30 mL of tetrahydrofuran to obtain solution A, 1.5 g of carboxymethyl cellulose is added to 30 mL of deionized water, stirred uniformly to obtain solution B, solution A and solution B are mixed, 7.6 g of potassium titanate whiskers loaded with porous carbon is added, tetrahydrofuran solvent is removed by distillation under reduced pressure at 45 DEG C, placed in a 105 DEG C oven and dried for 10 min to remove water, and modified potassium titanate whiskers are obtained; A6. 2.3 g modified potassium titanate whiskers and 1.7 g composite layered material were added into 50 mL of ethanol and 15 mL of deionized water, stirred uniformly, 45% ammonia water was added to adjust the pH to 8.5, 10 g of tetraethyl orthosilicate was added, stirred at 45℃ for 1.5 h, cooled to room temperature, and freeze-dried at -20℃ for 20 h to obtain a composite flame retardant material. Embodiment

[0035] A method for preparing a high-strength polyester fiber, comprising the following preparation steps: S1. After drying the polyester chips at 120℃ for 2 h, mix with the composite flame retardant material, stir at 600 r / min for 40 min to obtain a blend; S2. The blend is melt-spun, drawn, and wound to form a high-strength polyester fiber; wherein the mass ratio of polyester chips to composite flame retardant material is 120:25; The melt spinning is carried out on a double-screw high-speed composite spinning machine, the spinning speed is 1200 m / min, and the spinning machine temperature is 290℃; The drawing is carried out on a parallel drawing machine, the temperature is 90℃, the drawing speed is 400 m / min, and the drawing ratio is 6.5.

[0036] The composite flame retardant material is prepared by the following steps: A1. 4.4 g of α-zirconium phosphate nanosheets were added to 50 mL of Tris-HCl buffer with a pH of 8.5, stirred uniformly, 0.5 g of dopamine was added, stirred for 5 h, filtered, washed with deionized water 3 times, and dried in a 70℃ oven for 10 min to obtain polydopamine-modified α-zirconium phosphate nanosheets; A2. 6 g of polydopamine-modified α-zirconium phosphate nanosheets were added to 55 mL of deionized water, stirred uniformly, 1.9 g of lanthanum chloride and 55 mL of ethanol were added, stirred and mixed for 40 min, 3 g of phenyl phosphonic acid was added, stirred uniformly, placed in a reaction kettle, reacted at 120℃ for 12 h, cooled to room temperature, filtered, washed with deionized water 5 times, and dried in an 80℃ oven for 15 min to obtain a composite layered material; A3. 5 g of glucose was added to 55 mL of ethanol, stirred uniformly, 11 g of potassium titanate whiskers was added, stirred and mixed at 90℃ for 40 min, placed in a tube furnace, 6 mL of 52.8% potassium hydroxide solution was added, nitrogen was introduced, carbonized at 900℃ for 5 h, cooled to room temperature, removed, washed with deionized water 3 times, and dried in a 70℃ oven for 10 min to obtain porous carbon-loaded potassium titanate whiskers; A4. 2g hexachlorocyclotriphosphazene, 3g p-hydroxybenzaldehyde, 0.6g potassium carbonate were added into 45mL tetrahydrofuran, argon was bubbled, the reaction was stirred for 5h, tetrahydrofuran was evaporated under reduced pressure at 40℃, then it was placed in 90mL deionized water, stirred until a precipitate was formed, the precipitate was filtered, washed with deionized water for 3 times, dried in a 50℃ oven for 10min, to obtain hexachlorocyclotriphosphazene derivative; A5. 3g hexachlorocyclotriphosphazene derivative was added into 35mL tetrahydrofuran to obtain solution A, 2g carboxymethyl cellulose was added into 35mL deionized water, stirred uniformly to obtain solution B, solution A and solution B were mixed, 8g porous carbon loaded potassium titanate whisker was added, tetrahydrofuran solvent was removed by distillation under reduced pressure at 45℃, then it was placed in a 105℃ oven and dried for 10min to remove water, to obtain modified potassium titanate whisker; A6. 2.4g modified potassium titanate whisker and 1.8g composite layered material were added into 55mL ethanol and 20mL deionized water, stirred uniformly, 45% mass fraction of ammonia water was added to adjust the pH to 8.5, 12g tetraethyl orthosilicate was added, stirred at 50℃ for 2h, cooled to room temperature, and freeze-dried at -20℃ for 20h, to obtain composite flame retardant material.

[0037] Comparative Example 1 A method for preparing a high-strength polyester fiber, comprising the following preparation steps: S1. After the polyester chip was dried at 120℃ for 2h, it was mixed with the composite flame retardant material, stirred at 600r / min for 40min to obtain a blend; S2. The blend was melt-spun, drawn, and wound to form a high-strength polyester fiber; wherein the mass ratio of the polyester chip to the composite flame retardant material is 120:25; The melt spinning was performed on a double-screw high-speed composite spinning machine, the spinning speed was 1200m / min, and the spinning machine temperature was 290℃; The drawing was performed on a parallel drawing machine, the temperature was 90℃, the drawing speed was 400m / min, and the drawing multiple was 6.5.

[0038] The composite flame retardant material was prepared by the following steps: A1. 6g α-zirconium phosphate nanosheet was added into 55mL deionized water, stirred uniformly, 1.9g lanthanum chloride and 55mL ethanol were added, stirred and mixed for 40min, 3g phenyl phosphonic acid was added, stirred uniformly, placed in a reaction kettle, reacted at 120℃ for 12h, cooled to room temperature, filtered, washed with deionized water for 5 times, and dried in an 80℃ oven for 15min to obtain a composite layered material; A2. 5 g of glucose was added to 55 mL of ethanol, stirred uniformly, 11 g of potassium titanate whisker was added, the mixture was stirred at 90℃ for 40 min, placed in a tube furnace, 6 mL of 52.8% mass fraction potassium hydroxide solution was added, nitrogen was introduced, carbonization was carried out at 900℃ for 5 h, cooled to room temperature, taken out, washed with deionized water for 3 times, dried in a 70℃ oven for 10 min, to obtain potassium titanate whisker loaded with porous carbon; A3. 2 g of hexachlorocyclotriphosphazene, 3 g of p-hydroxybenzaldehyde, and 0.6 g of potassium carbonate were added to 45 mL of tetrahydrofuran, argon was introduced, and the reaction was stirred for 5 h. After the tetrahydrofuran was distilled off under reduced pressure at 40℃, it was placed in 90 mL of deionized water and stirred until a precipitate was formed. The precipitate was filtered, washed with deionized water for 3 times, and dried in a 50℃ oven for 10 min to obtain a hexachlorocyclotriphosphazene derivative; A4. 3 g of the hexachlorocyclotriphosphazene derivative was added to 35 mL of tetrahydrofuran to obtain solution A. 2 g of carboxymethyl cellulose was added to 35 mL of deionized water and stirred uniformly to obtain solution B. Solution A and solution B were mixed, 8 g of potassium titanate whisker loaded with porous carbon was added, and the tetrahydrofuran solvent was removed by vacuum distillation at 45℃. The mixture was placed in a 105℃ oven for 10 min to remove water to obtain modified potassium titanate whisker; A5. 2.4 g of the modified potassium titanate whisker and 1.8 g of the composite layered material were added to 55 mL of ethanol and 20 mL of deionized water, stirred uniformly, and the pH was adjusted to 8.5 by adding 45% mass fraction ammonia water. 12 g of tetraethyl orthosilicate was added, and the reaction was stirred at 50℃ for 2 h. The mixture was cooled to room temperature and freeze-dried at -20℃ for 20 h to obtain a composite flame-retardant material.

[0039] Comparative Example 2 A method for preparing a high-strength polyester fiber, comprising the following preparation steps: S1. After the polyester chip was dried at 120℃ for 2 h, it was mixed with the composite flame-retardant material, and stirred at 600 r / min for 40 min to obtain a blend; S2. The blend was melt-spun, drawn, and wound to form a high-strength polyester fiber; wherein the mass ratio of the polyester chip to the composite flame-retardant material is 120:25; The melt spinning was performed on a double-screw high-speed composite spinning machine, with a spinning speed of 1200 m / min and a spinning machine temperature of 290℃; The drawing was performed on a parallel drawing machine, with a temperature of 90℃, a drawing speed of 400 m / min, and a drawing ratio of 6.5.

[0040] The composite flame-retardant material was prepared by the following steps: A1. 4.4 g of zirconium alpha-phosphate nanosheets were added to 50 mL of Tris-HCl buffer with a pH of 8.5, stirred uniformly, 0.5 g of dopamine was added, stirred for 5 h, filtered, washed with deionized water for 3 times, dried in an oven at 70°C for 10 min, and polydopamine modified zirconium alpha-phosphate nanosheets were obtained; A2. 5 g of glucose was added to 55 mL of ethanol, stirred uniformly, 11 g of potassium titanate whiskers was added, stirred at 90°C for 40 min, placed in a tube furnace, 6 mL of 52.8% potassium hydroxide solution was added, nitrogen was introduced, carbonized at 900°C for 5 h, cooled to room temperature, removed, washed with deionized water for 3 times, dried in an oven at 70°C for 10 min, and porous carbon loaded potassium titanate whiskers were obtained; A3. 2 g of hexachlorocyclotriphosphazene, 3 g of p-hydroxybenzaldehyde, and 0.6 g of potassium carbonate were added to 45 mL of tetrahydrofuran, argon was introduced, stirred for 5 h, after removing tetrahydrofuran at 40°C under reduced pressure, placed in 90 mL of deionized water, stirred until a precipitate was formed, the precipitate was filtered, washed with deionized water for 3 times, and dried in an oven at 50°C for 10 min, and hexachlorocyclotriphosphazene derivative was obtained; A4. 3 g of hexachlorocyclotriphosphazene derivative was added to 35 mL of tetrahydrofuran to obtain solution A, 2 g of carboxymethyl cellulose was added to 35 mL of deionized water, stirred uniformly to obtain solution B, solution A and solution B were mixed, 8 g of porous carbon loaded potassium titanate whiskers was added, removed tetrahydrofuran solvent by vacuum distillation at 45°C, placed in an oven at 105°C for 10 min to remove water, and modified potassium titanate whiskers were obtained; A6. 2.4 g of modified potassium titanate whiskers and 1.8 g of polydopamine modified zirconium alpha-phosphate nanosheets were added to 55 mL of ethanol and 20 mL of deionized water, stirred uniformly, the pH was adjusted to 8.5 by adding 45% ammonia water, 12 g of tetraethyl orthosilicate was added, stirred at 50°C for 2 h, cooled to room temperature, and freeze-dried at -20°C for 20 h to obtain a composite flame retardant material.

[0041] Comparative Example 3 A method for preparing a high-strength polyester fiber, comprising the following preparation steps: S1. After drying the polyester chip at 120°C for 2 h, the polyester chip was mixed with the composite flame retardant material, stirred at 600 r / min for 40 min to obtain a blend; S2. The blend was melt-spun, drawn, and wound to form a high-strength polyester fiber; wherein the mass ratio of the polyester chip to the composite flame retardant material is 120:25; The melt spinning was performed on a double-screw high-speed composite spinning machine, the spinning speed was 1200 m / min, and the spinning machine temperature was 290°C. The drawing is performed on a parallel drawing machine at a temperature of 90 DEG C, a drawing speed of 400 m / min, and a drawing ratio of 6.5.

[0042] The composite flame-retardant material is prepared by the following steps: A1. 4.4 g of α-zirconium phosphate nanosheets are added to 50 mL of Tris-HCl buffer with a pH of 8.5, stirred uniformly, 0.5 g of dopamine is added, stirred for 5 h, filtered, washed with deionized water for 3 times, dried in a 70 DEG C oven for 10 min, and α-zirconium phosphate nanosheets modified by polydopamine are obtained; A2. 6 g of α-zirconium phosphate nanosheets modified by polydopamine are added to 55 mL of deionized water, stirred uniformly, 1.9 g of lanthanum chloride and 55 mL of ethanol are added, stirred and mixed for 40 min, 3 g of phenyl phosphonic acid is added, stirred uniformly, placed in a reaction kettle, reacted at 120 DEG C for 12 h, cooled to room temperature, filtered, washed with deionized water for 5 times, dried in an 80 DEG C oven for 15 min, and a composite layered material is obtained; A3. 2 g of hexachlorocyclotriphosphazene, 3 g of p-hydroxybenzaldehyde, and 0.6 g of potassium carbonate are added to 45 mL of tetrahydrofuran, argon is introduced, stirred and reacted for 5 h, tetrahydrofuran is distilled out under reduced pressure at 40 DEG C, placed in 90 mL of deionized water, stirred until a precipitate is formed, filtered to obtain the precipitate, the precipitate is washed with deionized water for 3 times, dried in a 50 DEG C oven for 10 min, and a hexachlorocyclotriphosphazene derivative is obtained; A4. 3 g of the hexachlorocyclotriphosphazene derivative is added to 35 mL of tetrahydrofuran to obtain solution A, 2 g of carboxymethyl cellulose is added to 35 mL of deionized water, stirred uniformly to obtain solution B, solution A and solution B are mixed, 8 g of potassium titanate whiskers are added, tetrahydrofuran solvent is removed by distillation under reduced pressure at 45 DEG C, placed in a 105 DEG C oven to dry for 10 min to remove water, and modified potassium titanate whiskers are obtained; A5. 2.4 g of the modified potassium titanate whiskers and 1.8 g of the composite layered material are added to 55 mL of ethanol and 20 mL of deionized water, stirred uniformly, ammonia water with a mass fraction of 45% is added to adjust the pH to 8.5, 12 g of tetraethyl orthosilicate is added, stirred and reacted at 50 DEG C for 2 h, cooled to room temperature, and freeze-dried at -20 DEG C for 20 h to obtain the composite flame-retardant material.

[0043] Comparative Example 4 A method for preparing a high-strength polyester fiber, comprising the following preparation steps: S1. After the polyester chip is dried at 120 DEG C for 2 h, the composite flame-retardant material is mixed, stirred at 600 r / min for 40 min, and a blend is obtained; S2. The blend is melt-spun, drawn, and wound to form a high-strength polyester fiber. wherein the mass ratio of the polyester chip and the composite flame-retardant material is 120:25; The melt spinning is performed on a double-screw high-speed composite spinning machine, the spinning speed is 1200 m / min, and the spinning machine temperature is 290 DEG C; The drawing is performed on a parallel drawing machine, the temperature is 90 DEG C, the drawing speed is 400 m / min, and the drawing multiple is 6.5.

[0044] The composite flame-retardant material is specifically prepared by the following steps: A1. 4.4 g of alpha-zirconium phosphate nanosheets is added to 50 mL of Tris-HCl buffer with a pH of 8.5, stirred uniformly, 0.5 g of dopamine is added, stirred for 5 h, filtered, washed with deionized water for 3 times, dried in a 70 DEG C oven for 10 min, and polydopamine modified alpha-zirconium phosphate nanosheets are obtained; A2. 6 g of polydopamine modified alpha-zirconium phosphate nanosheets is added to 55 mL of deionized water, stirred uniformly, 1.9 g of lanthanum chloride and 55 mL of ethanol are added, stirred and mixed for 40 min, 3 g of phenyl phosphonic acid is added, stirred uniformly, placed in a reaction kettle, reacted at 120 DEG C for 12 h, cooled to room temperature, filtered, washed with deionized water for 5 times, and dried in an 80 DEG C oven for 15 min to obtain a composite layered material; A3. 5 g of glucose is added to 55 mL of ethanol, stirred uniformly, 11 g of potassium titanate whiskers is added, stirred and mixed at 90 DEG C for 40 min, placed in a tube furnace, 6 mL of 52.8% potassium hydroxide solution is added, nitrogen is introduced, carbonized at 900 DEG C for 5 h, cooled to room temperature, taken out, washed with deionized water for 3 times, and dried in a 70 DEG C oven for 10 min to obtain potassium titanate whiskers loaded with porous carbon; A4. 3 g of hexachlorocyclotriphosphazene is added to 35 mL of tetrahydrofuran to obtain solution A, 2 g of carboxymethyl cellulose is added to 35 mL of deionized water, stirred uniformly to obtain solution B, solution A and solution B are mixed, 8 g of potassium titanate whiskers loaded with porous carbon is added, the tetrahydrofuran solvent is removed by vacuum distillation at 45 DEG C, and the moisture is removed by drying in a 105 DEG C oven for 10 min to obtain modified potassium titanate whiskers; A5. 2.4 g of modified potassium titanate whiskers and 1.8 g of composite layered material are added to 55 mL of ethanol and 20 mL of deionized water, stirred uniformly, the pH is adjusted to 8.5 by adding 45% ammonia water, 12 g of tetraethyl orthosilicate is added, stirred and reacted at 50 DEG C for 2 h, cooled to room temperature, and freeze-dried at -20 DEG C for 20 h to obtain a composite flame-retardant material.

[0045] Comparative Example 5 A preparation method of a high-strength polyester fiber, comprising the following preparation steps: S1. After drying the polyester chips at 120℃ for 2h, mix with the composite flame retardant material, stir at 600r / min for 40min to obtain a blend; S2. The blend is melt-spun, drawn, and wound to form high-strength polyester fibers; wherein the mass ratio of polyester chips to composite flame retardant material is 120:25; The melt spinning is performed on a double-screw high-speed composite spinning machine, the spinning speed is 1200m / min, and the spinning machine temperature is 290℃; The drawing is performed on a parallel drawing machine, the temperature is 90℃, the drawing speed is 400m / min, and the drawing multiple is 6.5.

[0046] The composite flame retardant material is specifically prepared by the following steps: A1. Add 4.4g of alpha-zirconium phosphate nanosheets to 50mL of Tris-HCl buffer with a pH of 8.5, stir until uniform, add 0.5g of dopamine, stir for 5h, filter, wash with deionized water 3 times, and dry in a 70℃ oven for 10min to obtain polydopamine-modified alpha-zirconium phosphate nanosheets; A2. Add 6g of polydopamine-modified alpha-zirconium phosphate nanosheets to 55mL of deionized water, stir until uniform, add 1.9g of lanthanum chloride and 55mL of ethanol, stir and mix for 40min, add 3g of phenyl phosphonic acid, stir until uniform, place in a reaction kettle, react at 120℃ for 12h, cool to room temperature, filter, wash with deionized water 5 times, and dry in an 80℃ oven for 15min to obtain a composite layered material; A3. Add 5g of glucose to 55mL of ethanol, stir until uniform, add 11g of potassium titanate whiskers, stir and mix at 90℃ for 40min, place in a tube furnace, add 6mL of a 52.8% by mass potassium hydroxide solution, introduce nitrogen, and carbonize at 900℃ for 5h, cool to room temperature, remove, wash with deionized water 3 times, and dry in a 70℃ oven for 10min to obtain porous carbon-loaded potassium titanate whiskers; A4. Add 2g of hexachlorocyclotriphosphazene, 3g of p-hydroxybenzaldehyde, and 0.6g of potassium carbonate to 45mL of tetrahydrofuran, introduce argon, stir and react for 5h, evaporate the tetrahydrofuran under reduced pressure at 40℃, place in 90mL of deionized water, stir until a precipitate forms, filter the precipitate, wash the precipitate with deionized water 3 times, and dry in a 50℃ oven for 10min to obtain a hexachlorocyclotriphosphazene derivative; A5. 3 g of hexachlorocyclotriphosphazene derivative was added to 35 mL of tetrahydrofuran to obtain solution A, 2 g of carboxymethyl cellulose was added to 35 mL of deionized water and stirred uniformly to obtain solution B, solution A and solution B were mixed, 8 g of porous carbon loaded potassium titanate whisker was added, the tetrahydrofuran solvent was removed by distillation under reduced pressure at 45°C, and the water was removed by drying in an oven at 105°C for 10 min to obtain modified potassium titanate whisker; A6. 2.4 g of modified potassium titanate whisker and 1.8 g of composite layered material were mixed to obtain a composite flame retardant material.

[0047] The high-strength polyester fibers prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to performance testing.

[0048] Flame retardant performance test: using a high temperature oxygen index tester, the high-strength polyester fibers prepared above were wound on a length tester for 40 m, and twisted with a twist number of 130, folded in half along the middle to form a strand, and the ends were fixed. The limiting oxygen index was tested according to the "Polyester Fiber Flame Retardant Performance Test Method Oxygen Index Method FZT50017-2001". The vertical burning (UL-94) combustion test box was used to test the flame retardant grade of the high-strength polyester fibers prepared above.

[0049] Elongation at break test: the high-strength polyester fibers prepared above were subjected to elongation at break test on a multifilament strength tester with a pre-tension of 3 cN, a tensile speed of 200 mm / min, and a clamping distance of 200 mm.

[0050] Breaking strength test: the breaking strength of the high-strength polyester fibers prepared above was tested according to the GB / T14344-2022 standard with a clamping distance of 250 mm and a tensile speed of 200 mm / min.

[0051] As shown in Table 1 below.

[0052] Table 1 Performance testing of high-strength polyester fibers prepared in Examples 1-3 and Comparative Examples 1-5 Item Filament fineness dtex Elongation at break / % Breaking strength cN / Tex Limiting oxygen index / % UL-94 rating Example 1 2.4 71.3 3.63 33.2 V-0 Example 2 2.5 72.2 3.78 34.5 V-0 Example 3 2.3 70.8 3.56 32.8 V-0 Comparative Example 1 2.1 61.2 2.05 25.3 V-1 Comparative Example 2 2.0 56.3 1.65 23.1 V-2 Comparative Example 3 2.1 59.7 1.98 25.9 V-1 Comparative Example 4 2.0 55.1 1.59 31.5 V-0 Comparative Example 5 2.2 62.3 2.35 26.8 V-1 As can be seen from the data in Table 1, the high-strength polyester fibers prepared in Examples 1-3 have high mechanical properties and flame retardancy.

[0053] In Comparative Example 1, the polydopamine modified α-zirconium phosphate nanosheet was replaced by α-zirconium phosphate nanosheet to prepare a composite flame retardant material, which was added to the high-strength polyester fiber, and the mechanical strength and flame retardant performance decreased, proving that the polydopamine modified α-zirconium phosphate nanosheet made the α-zirconium phosphate nanosheet have excellent adhesion performance, which was beneficial to the synthesis of layered lanthanum phenylphosphonate on the α-zirconium phosphate nanosheet, and improved the mechanical properties and flame retardant properties of the polyester fiber.

[0054] The composite flame-retardant material prepared by replacing the composite layered material with the polydopamine modified α-zirconium phosphate nanosheet in Comparative Example 2 is added to the high-strength polyester fiber, and the mechanical strength decreases, which proves that the layered structure of the lanthanum phenyl phosphonate coating on the upper and lower surfaces of the α-zirconium phosphate nanosheet can form an effective barrier layer in the polyester fiber, slow down the combustion process, and catalyze the polyester molecular chains in the polyester fiber to crosslink into carbon quickly, and the formed composite layered material can absorb external stress and improve the mechanical properties of the polyester fiber.

[0055] In Comparative Example 3, the composite flame-retardant material prepared by replacing the porous carbon loaded potassium titanate whisker with the modified potassium titanate whisker is added to the high-strength polyester fiber, and the mechanical strength and flame-retardant performance decrease, which proves that the synthesis of porous carbon on the surface of the potassium titanate whisker increases the surface roughness and improves the contact area between the potassium titanate whisker and the polyester fiber matrix, so that the polyester fiber exhibits excellent heat stability and mechanical properties, and the porous carbon loaded potassium titanate whisker acts as a carrier for hexachlorocyclotriphosphazene derivatives and carboxymethyl cellulose, avoiding the migration and precipitation of the flame-retardant material and improving the flame-retardant performance.

[0056] In Comparative Example 4, the composite flame-retardant material prepared by replacing the hexachlorocyclotriphosphazene derivative with hexachlorocyclotriphosphazene is added to the high-strength polyester fiber, and the mechanical strength decreases, which proves that the p-hydroxybenzaldehyde grafted on the hexachlorocyclotriphosphazene molecule provides a large number of reactive functional groups of hydroxyl and rigid benzene ring structures, which act on the polyester fiber to improve the mechanical strength of the polyester fiber.

[0057] In Comparative Example 5, the composite flame-retardant material prepared without adding tetraethyl orthosilicate is added to the high-strength polyester fiber, and the mechanical strength and flame-retardant performance decrease, which proves that the composite layered lanthanum phenyl phosphonate and the modified potassium titanate whisker are embedded in the silica aerogel structure, increasing the crosslinking density of the silica aerogel and enhancing the mechanical properties, and the formed silica aerogel has a porous structure, which can adsorb molten polyester chips, so that the silica aerogel is uniformly pulverized in the polyester fiber, improving the mechanical properties and flame-retardant performance of the polyester fiber.

[0058] In the description of the specification, the description of the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0059] The above merely illustrates and describes the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or adopt similar ways to replace, as long as the modifications or supplements do not deviate from the present application or exceed the scope defined by the present application, and should belong to the protection scope of the present application.

Claims

1. A process for the production of high-strength polyester fibers, characterized in that, The preparation steps include: S1. After drying the polyester chip at 100-120℃ for 1-2h, mix it with the composite flame retardant material, stir at 500-600r / min for 30-40min to obtain a blend; S2. The blend is melt-spun, drawn and wound to form high-strength polyester fibers; The composite flame retardant material is obtained by mixing and reacting the composite layered material, modified potassium titanate whisker and tetraethyl orthosilicate, and then freeze-drying; The composite layered material is obtained by mixing and reacting the polydopamine surface modified alpha-zirconium phosphate nanosheet, lanthanum chloride and phenyl phosphonic acid; The modified potassium titanate whisker is obtained by mixing and reacting the potassium titanate whisker, glucose, carboxymethyl cellulose and hexachlorocyclotriphosphazene derivative after calcination.

2. The method for preparing high-strength polyester fiber according to claim 1, characterized in that, The composite flame retardant material is prepared by the following steps: A1. Add the alpha-zirconium phosphate nanosheet to the Tris-HCl buffer solution, stir until uniform, add dopamine, stir for 3-5h, filter, wash and dry to obtain the polydopamine modified alpha-zirconium phosphate nanosheet; A2. Add the polydopamine modified alpha-zirconium phosphate nanosheet to the deionized water, stir until uniform, add lanthanum chloride and ethanol, stir for 30-40min, add phenyl phosphonic acid, stir until uniform, place in a reaction kettle, react at 100-120℃ for 10-12h, cool to room temperature, filter, wash and dry to obtain the composite layered material; A3. Add glucose to ethanol, stir until uniform, add potassium titanate whisker, stir and mix at 80-90℃ for 30-40min, place in a tube furnace, add potassium hydroxide solution, introduce nitrogen, carbonize at 800-900℃ for 3-5h, cool to room temperature, take out, wash and dry to obtain the porous carbon loaded potassium titanate whisker; A4. Add hexachlorocyclotriphosphazene, p-hydroxybenzaldehyde and potassium carbonate to tetrahydrofuran, introduce argon, stir for 3-5h, evaporate tetrahydrofuran under reduced pressure, place in deionized water, stir until a precipitate is formed, filter to obtain the precipitate, wash and dry the precipitate to obtain the hexachlorocyclotriphosphazene derivative; A5. Add the hexachlorocyclotriphosphazene derivative to tetrahydrofuran to obtain solution A, add carboxymethyl cellulose to deionized water, stir until uniform to obtain solution B, mix solution A and solution B, add the porous carbon loaded potassium titanate whisker, evaporate tetrahydrofuran under reduced pressure, dry to obtain the modified potassium titanate whisker; A6. Add the modified potassium titanate whisker and the composite layered material to ethanol and deionized water, stir until uniform, add ammonia water to adjust the pH, add tetraethyl orthosilicate, stir at 40-50℃ for 1-2h, cool to room temperature, freeze-dry to obtain the composite flame retardant material.

3. The method for preparing high-strength polyester fiber according to claim 2, characterized in that, In step A1, the amount ratio of the alpha-zirconium phosphate nanosheet, Tris-HCl buffer solution and dopamine is (4.2-4.4)g:(40-50)mL:(0.3-0.5)g.

4. The method for preparing high-strength polyester fiber according to claim 2, characterized in that, In step A2, the polydopamine modified α-zirconium phosphate nanosheet, deionized water, lanthanum chloride, ethanol and phenyl phosphonic acid were used in a ratio of (5-6) g:(45-55) mL:(1.5-1.9) g:(45-55) mL:(2-3) g.

5. The method for preparing high-strength polyester fiber according to claim 2, characterized in that, In step A3, the glucose, ethanol, potassium titanate whisker and potassium hydroxide solution were used in a ratio of (4-5) g:(45-55) mL:(10-11) g:(4-6) mL.

6. The method for preparing high-strength polyester fiber according to claim 2, characterized in that, In step A4, the hexachlorocyclotriphosphazene, p-hydroxybenzaldehyde, potassium carbonate, tetrahydrofuran and deionized water were used in a ratio of (1-2) g:(2-3) g:(0.4-0.6) g:(35-45) mL:(70-90) mL.

7. The method for preparing high-strength polyester fiber according to claim 2, characterized in that, In step A5, the hexachlorocyclotriphosphazene derivative, tetrahydrofuran, carboxymethyl cellulose, deionized water and porous carbon loaded potassium titanate whisker were used in a ratio of (2-3) g:(25-35) mL:(1-2) g:(25-35) mL:(7-8) g.

8. The method for preparing high-strength polyester fiber according to claim 2, characterized in that, In step A6, the modified potassium titanate whisker, composite layered material, ethanol, deionized water and tetraethyl orthosilicate were used in a ratio of (2.2-2.4) g:(1.6-1.8) g:(45-55) mL:(10-20) mL:(8-12) g.

9. A high-strength polyester fiber prepared by the method of any one of claims 1-8.