Modified polyester material for high-strength fabric and method for preparing the same
By extending the chain of polyester materials and introducing phosphate ester groups and sulfonic acid groups, the problem of maintaining high strength and high modulus while improving the moisture absorption and antistatic properties of polyester materials was solved, achieving multiple improvements in the flame retardancy, moisture absorption, antistatic properties and dyeing properties of high-strength fabrics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HONGYU TEXTILE ZHEJIANG CO LTD
- Filing Date
- 2026-06-01
- Publication Date
- 2026-06-30
AI Technical Summary
While improving wearing comfort and moisture absorption, existing polyester materials sacrifice high strength and high modulus properties, and also suffer from problems such as static electricity buildup and dyeing difficulties.
Polyester was modified by introducing chain extender modifiers. Flame retardant monomers were prepared by cross-dehydrogenation coupling reaction of p-aminophenol and diethyl phosphite, and then obtained by Michael addition reaction with sodium vinyl sulfonate to obtain hygroscopic monomers. Finally, modified copolyester fibers were prepared by ring-opening esterification reaction with 2,3,6,7-naphthalenetetracarboxylic dianhydride. The combination of multiple modifications of phosphate ester groups and sulfonic acid groups improved the hygroscopicity, antistatic properties and flame retardant properties of the material.
It achieves improvements in the strength, moisture absorption, antistatic properties, and flame retardancy of polyester materials, while retaining the linear regularity and abrasion resistance of the fibers, thus improving the comfort and processing performance of the materials.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of textile technology, specifically to a modified polyester material for high-strength fabrics and its preparation method. Background Technology
[0002] Polyester fiber, commonly known as polyester, is widely used in industrial fabrics, tents, webbing, ropes, and high-performance outdoor clothing due to its excellent mechanical properties such as high tensile strength, high elastic modulus, and good dimensional stability. Its high strength is microscopically attributed to the highly linearly symmetrical structure of its chain segments. During melt spinning and post-stretching, it readily crystallizes along the axial direction with high orientation, forming a dense oriented crystalline region structure, which endows the monofilament with extremely high axial tensile strength.
[0003] However, conventional polyester, when used as clothing or industrial fabrics, suffers from inherent defects such as extremely poor moisture absorption, severe static electricity buildup, a stiff and waxy feel, and the need for high-temperature and high-pressure environments for dyeing. To improve these aspects of wearing comfort and processing performance, existing technologies mainly involve chemical copolymerization modification of polyester to adjust the chemical structure and aggregation state of the macromolecular chain. For example, introducing a third monomer containing sodium sulfonate groups during the esterification or polycondensation stage can prepare cationic dyeable polyesters, utilizing the strong polarity and ionic properties of sulfonate groups to impart atmospheric pressure boiling dyeing, moisture absorption, and antistatic properties to the fiber. Alternatively, polyethylene glycol segments can be introduced to enhance hydrophilicity through hydrogen bonding of ether bonds. 2,5-furandicarboxylic acid can be used to replace terephthalic acid to prepare polyethylene furanate, utilizing the hydrogen bond acceptor effect and nonlinear structure of the oxygen atom in the furan ring to provide a new path for improving the moisture absorption of polyester. However, while optimizing wearing comfort, these copolymerization modification methods often come at the cost of sacrificing the inherent high strength and high modulus of polyester. The introduction of polar side groups such as sulfonic acid groups and ether bonds or irregular comonomers severely disrupts the linear regularity and stereosymmetry of polyester macromolecular chains, resulting in a significant decrease in the orientation crystallization ability of molecular chains during spinning and stretching, a significant increase in the proportion of amorphous regions, and a decrease in fiber breaking strength.
[0004] Based on this, the present invention will provide a method for preparing a modified polyester material for high-strength fabrics. Summary of the Invention
[0005] To address the shortcomings mentioned in the background art, the present invention aims to provide a modified polyester material for high-strength fabrics and its preparation method. By modifying polyester with a chain extender, the hygroscopicity, antistatic properties, colorfastness, flame retardancy, and abrasion resistance of the polyester material can be improved.
[0006] A modified polyester material for high-strength fabrics comprises the following raw materials in parts by weight: 100-110 parts modified copolyester, 0.1-0.3 parts antioxidant, 0.5-1.5 parts carbodiimide, and 0.2-0.4 parts light stabilizer; The modified copolyester is prepared by copolymerization of terephthalic acid, ethylene glycol and chain extender. The chain extender is prepared by cross-dehydrogenation coupling reaction of p-aminophenol and diethyl phosphite to obtain a flame retardant monomer, followed by Michael addition of the flame retardant monomer with sodium vinyl sulfonate to obtain a hygroscopic monomer, and then ring-opening esterification reaction of the hygroscopic monomer with 2,3,6,7-naphthalenetetracarboxylic dianhydride.
[0007] More preferably, the antioxidant is antioxidant 1010, antioxidant 330, or antioxidant 1098.
[0008] More preferably, the light stabilizer is UV-944, UV-622, or UV-770.
[0009] More preferably, the method for preparing the modified copolyester includes the following steps: Terephthalic acid, ethylene glycol, and chain extender were placed in a reactor. Trimethyl phosphate stabilizer and antimony catalyst were added under a nitrogen atmosphere. The reactor was placed at 230-250℃ for 2-4 hours. After the reaction was completed, the temperature was raised to 260-270℃. After a 40-60 minute pre-condensation reaction under vacuum, the temperature inside the reactor was controlled at 270-280℃ and the vacuum degree was below 60 Pa. The reaction was continued for 2-3 hours to obtain the modified copolyester.
[0010] More preferably, the antimony-based catalyst is antimony trioxide or antimony glycol.
[0011] More preferably, the addition ratio of terephthalic acid, ethylene glycol, chain extender, trimethyl phosphate stabilizer and antimony catalyst is 64-70g: 27-31mL: 20-22g: 0.025-0.027g: 0.025-0.027g.
[0012] More preferably, the preparation method of the chain extender modifier includes the following steps: S1. Take p-aminophenol, diethyl phosphite, and iodine into a reactor, add toluene, stir and react at room temperature for 30-40 min. After the reaction is complete, remove the solvent by rotary evaporation of the mixture, extract with ethyl acetate and retain the organic phase, wash the organic phase with saturated brine and dry it to obtain the flame retardant monomer. S2. Take flame retardant monomer, lithium hydroxide and ethanol into a reactor, add sodium vinyl sulfonate dropwise. After the addition is complete, stir the reaction at room temperature for 3-5 hours. After the reaction is complete, filter the mixture and retain the filtrate. Then, remove the solvent by rotary evaporation and cool the filtrate to crystallize and obtain the hygroscopic monomer. S3. Take the hygroscopic monomer, N,N dimethylformamide and place them in a reactor. Add 2,3,6,7-naphthalenetetracarboxylic dianhydride and an organic base catalyst. React at 50-60℃ for 5-7 hours. After the reaction is completed, quench the reaction solution with ice water. Then extract the quenched solution with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and then dry and rotary evaporate to obtain the chain extender modifier.
[0013] More preferably, the addition ratio of p-aminophenol, diethyl phosphite, and iodine in step S1 is 11-14g: 16-20mL: 0.02-0.024g.
[0014] More preferably, the addition ratio of flame retardant monomer, lithium hydroxide, and sodium vinyl sulfonate in step S2 is 20-22g: 1.8-2.2g: 10-11mL.
[0015] More preferably, the organic base catalyst in step S3 is pyridine or triethylamine.
[0016] More preferably, in step S3, the addition ratio of the hygroscopic monomer, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and organic base catalyst is 22-25g:7.2-8g:6-6.6mL.
[0017] A method for preparing a modified polyester material for high-strength fabrics includes the following steps: Modified copolyester, antioxidant, carbodiimide, and light stabilizer are added to a screw extruder for melt extrusion, and then melt-spun to produce modified polyester fibers. Modified polyester materials are obtained by weaving and finishing processes.
[0018] More preferably, the melt extrusion temperature is 260-280℃.
[0019] The beneficial effects of this invention are: The phosphate ester groups in the modified monomer of this invention release phosphoric acid and metaphosphoric acid free radicals upon thermal decomposition. These phosphorus free radicals effectively capture active hydrogen free radicals and hydroxyl free radicals generated during combustion, inhibiting the continued combustion chain reaction and thus preventing the spread of flames. Simultaneously, the decomposition products form a glassy protective layer around the polymer, preventing the generated organic combustibles from spreading to the flame surface and isolating air. In addition, phosphate esters can promote the carbonization of combustible surfaces, forming a dense protective char layer, further blocking the transfer of heat and oxygen. The nitrogen and sulfur in the phosphate esters release non-combustible gases upon heating, diluting the concentration of combustible gases and inflating the char layer, thus playing an expansion flame-retardant role. The rigid naphthalene ring skeleton and phosphorus-containing groups work together to increase the viscosity and rigidity of the melt at high temperatures, effectively inhibiting the melting and dripping phenomenon during polyester combustion, preventing further fire spread and skin burns. The synergistic effect of these multiple actions enables the modified polyester material to achieve excellent flame-retardant performance.
[0020] The sulfonic acid groups and ether bonds in the modified monomer of this invention are extremely strong hydrophilic polar groups. Through hydrogen bonds, they firmly grasp water molecules, forming a continuous water molecule film on the fiber surface. This effectively adsorbs and locks in free water molecules, achieving a water absorption effect. After dissolving trace amounts of sulfonate, this water film becomes an electrolyte solution layer, providing a pathway for migratable ions and surface water film conductivity, significantly reducing fiber surface resistance and eliminating static electricity buildup. The sulfonic acid groups can also strongly adsorb water molecules through ion-dipole interactions, creating an osmotic pressure difference within the fiber, driving water vapor conduction, effectively improving the moisture regain of the modified polyester and eliminating a stuffy feeling. Furthermore, the sulfonate groups, as cationic dye acceptors, can also firmly adsorb dye cations through Coulomb attraction, achieving atmospheric pressure boiling dyeing with extremely high color fastness and vibrant, rich colors. Together, these factors improve the moisture absorption, antistatic, and dyeing properties of polyester materials.
[0021] Meanwhile, the chain extender modifier of this invention is a large-volume planar conjugated structure composed of two fused benzene rings. Compared with the original single-benzene ring para-structure, the naphthalene ring has a higher rotational barrier and heat distortion temperature. It can significantly improve the initial modulus and abrasion resistance of the fiber, while improving the glass transition temperature and heat distortion stability of the material. Furthermore, the chain extender modifier has a highly symmetrical bilateral equivalent substitution design, preserving the linear regularity of the copolyester molecular chain, so that the macromolecular chain can still maintain a high degree of extension and orientation ability in spatial orientation. Detailed Implementation
[0022] 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.
[0023] Example 1
[0024] A modified polyester material for high-strength fabrics comprises the following raw materials in parts by weight: 100 parts modified copolyester, 0.1 parts antioxidant 1010, 0.5 parts carbodiimide, and 0.2 parts light stabilizer UV-944; The method for preparing the modified copolyester includes the following steps: 64g of terephthalic acid, 27mL of ethylene glycol, and 20g of chain extender were placed in a reactor. Under a nitrogen atmosphere, 0.025g of trimethyl phosphate stabilizer and 0.025g of antimony catalyst were added. The reactor was placed at 230℃ for 4 hours. After the reaction was completed, the temperature was raised to 260℃. After a 60min vacuum pre-condensation reaction, the temperature inside the reactor was controlled at 270℃ and the vacuum degree was below 60Pa. The reaction was continued for 3 hours to obtain the modified copolyester. The preparation method of the chain extender modifier includes the following steps: S1. Take 11g of p-aminophenol, 16mL of diethyl phosphite and 0.02g of iodine into a reactor, add 150mL of toluene, stir the reaction at room temperature for 30min. After the reaction is completed, remove the solvent by rotary evaporation of the mixture, extract with ethyl acetate and retain the organic phase, wash the organic phase with saturated brine and dry it to obtain the flame retardant monomer. S2. Take 20g of flame retardant monomer, 1.8g of lithium hydroxide, and 100mL of ethanol into a reactor, add 10mL of sodium vinyl sulfonate dropwise, and stir the reaction at room temperature for 3h after the addition is complete. After the reaction is complete, filter the mixture and retain the filtrate. Then, remove the solvent by rotary evaporation and cool the filtrate to crystallize and obtain the hygroscopic monomer. S3. Take 22g of hygroscopic monomer and 100mL of N-N dimethylformamide into a reactor, add 7.2g of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 6g of organic base catalyst pyridine, and react at 50℃ for 7h. After the reaction is completed, quench the reaction solution with ice water, then extract the quenched solution with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and then dry and rotary evaporate to obtain the chain extender modifier. A method for preparing a modified polyester material for high-strength fabrics includes the following steps: 100g of modified copolyester, 0.1g of antioxidant 1010, 0.5g of carbodiimide, and 0.2g of light stabilizer UV-944 were added to a screw extruder and melt-extruded at 260℃. The resulting material was then melt-spun into modified polyester fiber, which was then woven and shaped to obtain the modified polyester material.
[0025] Example 2
[0026] A modified polyester material for high-strength fabrics comprises the following raw materials in parts by weight: 110 parts modified copolyester, 0.3 parts antioxidant 330, 1.5 parts carbodiimide, and 0.4 parts light stabilizer UV-622; The method for preparing the modified copolyester includes the following steps: 70g of terephthalic acid, 31mL of ethylene glycol, and 22g of chain extender were placed in a reactor. Under a nitrogen atmosphere, 0.027g of trimethyl phosphate stabilizer and 0.027g of antimony catalyst were added. The reactor was placed at 250℃ for 2 hours. After the reaction was completed, the temperature was raised to 270℃. After a 40-minute vacuum pre-condensation reaction, the temperature inside the reactor was controlled at 280℃ and the vacuum degree was below 60Pa. The reaction was continued for 2 hours to obtain the modified copolyester. The preparation method of the chain extender modifier includes the following steps: S1. Take 14g of p-aminophenol, 20mL of diethyl phosphite and 0.024g of iodine into a reactor, add 159mL of toluene, stir the reaction at room temperature for 40min. After the reaction is completed, remove the solvent by rotary evaporation of the mixture, extract with ethyl acetate and retain the organic phase, wash the organic phase with saturated brine and dry it to obtain the flame retardant monomer. S2. Take 22g of flame retardant monomer, 2.2g of lithium hydroxide, and 100mL of ethanol into a reactor, add 11mL of sodium vinyl sulfonate dropwise, and stir the reaction at room temperature for 5h after the addition is complete. After the reaction is complete, filter the mixture and retain the filtrate. Then, remove the solvent by rotary evaporation and cool the filtrate to crystallize and obtain the hygroscopic monomer. S3. Take 25g of hygroscopic monomer and 125mL of N,N dimethylformamide into a reactor, add 8g of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 6.6mL of triethylamine, and react at 60℃ for 5h. After the reaction is completed, quench the reaction solution with ice water, then extract the quenched solution with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and then dry and rotary evaporate to obtain the chain extender modifier. A method for preparing a modified polyester material for high-strength fabrics includes the following steps: 110g of modified copolyester, 0.3g of antioxidant 330, 1.5g of carbodiimide, and 0.4g of light stabilizer UV-622 were added to a screw extruder and melt-extruded at 280℃. The resulting material was then melt-spun into modified polyester fiber, which was then woven and shaped to obtain the modified polyester material.
[0027] Example 3
[0028] A modified polyester material for high-strength fabrics comprises the following raw materials in parts by weight: 105 parts modified copolyester, 0.2 parts antioxidant 1098, 1.0 part carbodiimide, and 0.3 parts light stabilizer UV-770; The method for preparing the modified copolyester includes the following steps: 67g of terephthalic acid, 29mL of ethylene glycol, and 21g of chain extender were placed in a reactor. Under a nitrogen atmosphere, 0.026g of trimethyl phosphate stabilizer and 0.026g of antimony catalyst were added. The reactor was placed at 240℃ for 3 hours. After the reaction was completed, the temperature was raised to 265℃. After a 50-minute vacuum pre-polymerization reaction, the temperature inside the reactor was controlled at 275℃ and the vacuum degree was below 60Pa. The reaction was continued for 2.5 hours to obtain the modified copolyester. The preparation method of the chain extender modifier includes the following steps: S1. Take 12.5g of p-aminophenol, 18mL of diethyl phosphite, and 0.022g of iodine into a reactor, add 150mL of toluene, stir the reaction at room temperature for 35min, after the reaction is completed, remove the solvent by rotary evaporation of the mixture, extract with ethyl acetate and retain the organic phase, wash the organic phase with saturated brine and dry it to obtain the flame retardant monomer. S2. Take 21g of flame-retardant monomer, 2.0g of lithium hydroxide, and 100mL of ethanol into a reactor, add 10.5mL of sodium vinyl sulfonate dropwise, and stir the reaction at room temperature for 4h after the addition is complete. After the reaction is complete, filter the mixture and retain the filtrate. Then, remove the solvent by rotary evaporation and cool the filtrate to crystallize and obtain the hygroscopic monomer. S3. Take 23.5g of hygroscopic monomer and 100mL of NN dimethylformamide into a reactor, add 7.6g of 2,3,6,7-naphthalenetetracarboxylic dianhydride and 6.3mL of pyridine, and react at 55℃ for 6h. After the reaction is completed, quench the reaction solution with ice water, then extract the quenched solution with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and then dry and rotary evaporate to obtain the chain extender modifier. A method for preparing a modified polyester material for high-strength fabrics includes the following steps: 105g of modified copolyester, 0.2g of antioxidant 1098, 1.0g of carbodiimide, and 0.3g of light stabilizer UV-770 were added to a screw extruder and melt-extruded at 270℃. The mixture was then melt-spun into modified polyester fibers, which were then woven and shaped to obtain modified polyester materials.
[0029] Comparative Example 1
[0030] A modified polyester material for high-strength fabrics comprises the following raw materials in parts by weight: 105 parts copolyester, 0.2 parts antioxidant 1098, 1.0 part carbodiimide, and 0.3 parts light stabilizer UV-770; The method for preparing the copolyester includes the following steps: 67g of terephthalic acid and 29mL of ethylene glycol were placed in a reactor. Under a nitrogen atmosphere, 0.026g of trimethyl phosphate stabilizer and 0.026g of antimony catalyst were added. The reactor was placed at 240℃ for 3 hours. After the reaction was completed, the temperature was raised to 265℃. After a 50-minute vacuum pre-condensation reaction, the temperature inside the reactor was controlled at 275℃ and the vacuum degree was below 60Pa. The reaction was continued for 2.5 hours to obtain the modified copolyester. A method for preparing a modified polyester material for high-strength fabrics includes the following steps: 105g of copolyester, 0.2g of antioxidant 1098, 1.0g of carbodiimide, and 0.3g of light stabilizer UV-770 were added to a screw extruder and melt-extruded at 270℃. The resulting material was then melt-spun into modified polyester fiber, which was then woven and shaped to obtain polyester material.
[0031] Performance testing
[0032] Hygroscopicity and antistatic properties testing: The nominal mass of each group of textile materials was tested according to GB / T 9994-2018, and the nominal moisture regain was calculated by testing the nominal mass of each group of materials. The half-life of each group of composite yarns was monitored in real time by a non-contact electrostatic voltage probe using high voltage corona discharge according to GB / T 12703.1-2021. The hygroscopicity and antistatic properties monitoring data obtained are shown in Table 1.
[0033] Table 1: Statistical Table of Monitoring Data on Hygroscopicity and Antistatic Properties
[0034] As can be seen from Table 1, compared with Comparative Example 1, Examples 1-3 have higher nominal mass and nominal moisture regain as well as shorter half-life, which shows that modifying polyester can effectively improve the moisture absorption and antistatic properties of the modified fabric.
[0035] Color fastness and flame retardancy: The color fastness grade of each group of materials with methylene blue as dye was tested according to GB / T 23976.1-2009, and the limiting oxygen index (IOR) of each group of materials was tested according to GB / T 5454-1997. The monitoring data of color fastness and flame retardancy are shown in Table 2.
[0036] Table 2: Statistical Table of Monitoring Data on Color Fixation and Flame Retardant Properties
[0037] As can be seen from Table 2, compared with Comparative Example 1, Examples 1-3 have higher color fastness grades and oxygen limiting index, which shows that modifying polyester can effectively improve the color fastness and flame retardant properties of the modified fabric.
[0038] Abrasion resistance test: Referring to GB / T 21196.2-2007, the polyester materials of Examples 1-3 and Comparative Example 1 were woven into plain weave and twill weave fabrics with warp and weft densities of 300D and 450D, respectively. The total number of friction cycles of each group of fabrics was tested. The fabrics were rubbed by planar motion with a Lissajious pattern. The sample clamps rotated freely around an axis perpendicular to the horizontal plane. The friction endpoint was the breakage of the polyester fabric. The abrasion resistance monitoring data obtained are shown in Table 3.
[0039] Table 3: Statistical Table of Wear Resistance Monitoring Data
[0040] As shown in Table 3, under the same specifications and weave conditions, the total number of friction cycles in Examples 1-3 was significantly higher than that in Comparative Example 1. This indicates that the introduction of a rigid naphthalene ring skeleton structure by the chain extender significantly improved the fiber's breaking strength while preserving the linear regularity of the macromolecular chain, making the fiber more resistant to surface wear and fiber breakage during friction. The abrasion resistance of the 300D modified polyester plain weave fabrics in Examples 1-3 was significantly higher than that of the 300D plain weave fabric and 450D twill fabric in Comparative Example 1. This result shows that through the synergistic effect of the chain extender on material modification and weave structure optimization, the abrasion resistance of low-specification modified polyester fabrics is stronger than that of high-specification unmodified polyester fabrics.
[0041] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.
Claims
1. A modified polyester material for high strength fabric, characterized by, The raw materials include the following parts by weight: 100-110 parts modified copolyester, 0.1-0.3 parts antioxidant, 0.5-1.5 parts carbodiimide, and 0.2-0.4 parts light stabilizer; The modified copolyester is prepared by copolymerization of terephthalic acid, ethylene glycol and chain extender. The chain extender is prepared by cross-dehydrogenation coupling reaction of p-aminophenol and diethyl phosphite to obtain a flame retardant monomer, followed by Michael addition of the flame retardant monomer with sodium vinyl sulfonate to obtain a hygroscopic monomer, and then ring-opening esterification reaction of the hygroscopic monomer with 2,3,6,7-naphthalenetetracarboxylic dianhydride.
2. A modified polyester material for high strength fabric as claimed in claim 1, wherein, The antioxidant is antioxidant 1010, antioxidant 330, or antioxidant 1098.
3. The modified polyester material for high strength fabric according to claim 1, characterized in that, The light stabilizer is UV-944, UV-622, or UV-770.
4. The modified polyester material for high strength fabric according to claim 1, characterized in that, The preparation method of the modified copolyester includes the following steps: Terephthalic acid, ethylene glycol, and chain extender were placed in a reactor. Trimethyl phosphate stabilizer and antimony catalyst were added under a nitrogen atmosphere. The reactor was placed at 230-250℃ for 2-4 hours. After the reaction was completed, the temperature was raised to 260-270℃. After a 40-60 minute pre-condensation reaction under vacuum, the temperature inside the reactor was controlled at 270-280℃ and the vacuum degree was below 60 Pa. The reaction was continued for 2-3 hours to obtain the modified copolyester.
5. The modified polyester material for high strength fabric according to claim 4, characterized in that, The antimony-based catalyst is antimony trioxide or antimony glycol; the addition ratio of terephthalic acid, ethylene glycol, chain extender, trimethyl phosphate stabilizer and antimony-based catalyst is 64-70g: 27-31mL: 20-22g: 0.025-0.027g: 0.025-0.027g.
6. The modified polyester material for high strength fabric according to claim 4, characterized in that, The preparation method of the chain extender modifier includes the following steps: S1. Take p-aminophenol, diethyl phosphite, and iodine into a reactor, add toluene, stir and react at room temperature for 30-40 min. After the reaction is complete, remove the solvent by rotary evaporation of the mixture, extract with ethyl acetate and retain the organic phase, wash the organic phase with saturated brine and dry it to obtain the flame retardant monomer. S2. Take flame retardant monomer, lithium hydroxide and ethanol into a reactor, add sodium vinyl sulfonate dropwise. After the addition is complete, stir the reaction at room temperature for 3-5 hours. After the reaction is complete, filter the mixture and retain the filtrate. Then, remove the solvent by rotary evaporation and cool the filtrate to crystallize and obtain the hygroscopic monomer. S3. Take the hygroscopic monomer, N,N dimethylformamide and place them in a reactor. Add 2,3,6,7-naphthalenetetracarboxylic dianhydride and an organic base catalyst. React at 50-60℃ for 5-7 hours. After the reaction is completed, quench the reaction solution with ice water. Then extract the quenched solution with ethyl acetate and retain the organic phase. Wash the organic phase with saturated brine and then dry and rotary evaporate to obtain the chain extender modifier.
7. A modified polyester material for high strength fabric as claimed in claim 6, wherein the modified polyester material is a copolymer of terephthalic acid and 1,4-butanediol. In step S1, the addition ratio of p-aminophenol, diethyl phosphite, and iodine is 11-14g: 16-20mL: 0.02-0.024g.
8. The modified polyester material for high strength fabric according to claim 6, characterized in that, In step S2, the addition ratio of flame retardant monomer, lithium hydroxide, and sodium vinyl sulfonate is 20-22g: 1.8-2.2g: 10-11mL.
9. The modified polyester material for high strength fabric according to claim 6, characterized in that, In step S3, the organic base catalyst is pyridine or triethylamine; the addition ratio of hygroscopic monomer, 2,3,6,7-naphthalenetetracarboxylic dianhydride and organic base catalyst is 22-25g:7.2-8g:6-6.6mL.
10. A method for preparing a high-strength modified polyester material for fabrics according to any one of claims 1-9, characterized in that, Includes the following steps: Modified copolyester, antioxidant, carbodiimide, and light stabilizer are added to a screw extruder for melt extrusion, and then melt-spun to produce modified polyester fibers. Modified polyester materials are obtained by weaving and finishing processes.