A method for preparing regenerated polyester fiber

Abstract

The invention discloses a preparation method of a regenerated polyester fiber, and relates to the technical field of polyester fibers. The present invention first utilizes (4-formylphenyl) phosphonic acid to combine with 2-(3-nitroaniline) acetohydrazide to form a Schiff base structure, achieves antibacterial effect, and simultaneously introduces phosphorus element to achieve flame retardant and anti-wear effect; then forms a modified wear-resistant agent of a cross-linked network structure with butanediol, significantly enhancing the wear-resistant effect of fiber; then utilizes 1,7-octadiene-3-ol and octene trichlorosilane copolymerization to make a modifier, form a cross-linked network structure, enhance wear-resistant effect, and simultaneously be able to suppress the burning of flame, achieve flame retardant effect; then attracts the modifier by hydroxylated carbon nanotubes to prepare modified carbon nanotubes in situ polymerization on its surface, improve carbon nanotube dispersibility, prevent fiber from falling off, and improve the wear resistance of material; finally, regenerated polyester fiber, modified wear-resistant agent, and composite modified carbon nanotube are mixed and melt-spun to achieve wear-resistant, antibacterial, flame-retardant effect.

Description

Technical Field

[0001] The present invention relates to the technical field of polyester fibers, in particular to a method for preparing regenerated polyester fibers. Background Art

[0002] With society's growing emphasis on renewable energy, recycled polyethylene terephthalate (RPET) fibers are gaining widespread application. Recycled polyester fiber products are used in a wide range of applications, including nonwovens, home textiles, and automotive applications. However, a lack of focus on product development has resulted in shrinking profit margins for recycled polyester production. Consequently, companies are increasingly focusing on developing multifunctional fiber products to increase the added value of recycled polyester (RPET) fibers.

[0003] In recent years, there has been a huge market demand for flame-retardant fiber products. Multifunctional fibers that combine flame retardancy with other functions have significantly increased the added value of fiber products, providing a competitive advantage in the increasingly competitive market. With the rapid development of the high-speed rail, aviation, and automotive industries, the demand for interior textiles for high-speed rail, aircraft, and automobiles is increasing. These sectors are demanding textiles that go beyond flame retardancy to include multifunctional products that combine flame retardancy with hygiene and health functions, such as flame-retardant and antibacterial products, flame-retardant wear-resistant products, and flame-retardant anion products. However, the limiting oxygen index (LOI) of waste polyester is only 20% to 22%, making it a flammable fiber. Therefore, recycling waste polyester and modifying polyester materials to provide flame retardancy, antibacterial properties, and wear resistance are of great significance. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing regenerated polyester fiber to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing regenerated polyester fiber, comprising the following preparation steps:

[0006] (1) 10-20 parts of (4-formylphenyl)phosphonic acid, 8-16 parts of 2-(3-nitroaniline)acetohydrazide, and 96-192 parts of anhydrous ethanol were mixed uniformly, heated to 74-80°C, and stirred at 100 rpm for 5-7 hours to obtain a crude product, which was purified to obtain a composite agent;

[0007] (2) 3-9 parts of the composite agent, 7-21 parts of butanediol, and 80-240 parts of toluene were mixed uniformly, heated to 100-110°C, stirred at 90 rpm for 6-8 hours, cooled to 25°C, and concentrated at a vacuum degree of -0.1 MPa and 40°C for 4-6 hours to obtain a modified wear-resistant agent;

[0008] (3) Under a nitrogen atmosphere, 3 to 7 parts of 1,7-octadien-3-ol, 8 to 12 parts of octene trichlorosilane, and 85 to 145 parts of toluene were mixed uniformly, the temperature was raised to 50 to 60° C., 5 to 9 parts of methylaluminoxane toluene solution were added dropwise at a rate of 1 drop / s, and the mixture was stirred at 80 rpm for 4 to 8 hours to obtain a reaction solution, which was crystallized to obtain a modifier;

[0009] (4) placing 14 to 22 parts of carbon nanotubes in a container, adding 32 to 50 parts of 15 wt% sulfuric acid and 28 to 46 parts of 15 wt% nitric acid, ultrasonically treating at 20 to 30°C for 1.5 to 2.5 hours, heating to 80 to 100°C for reaction for 1 to 3 hours, filtering the solid, washing it three times with deionized water, and drying it in an oven at 45 to 55°C for 6 to 10 hours to obtain hydroxylated carbon nanotubes;

[0010] (5) 12 to 36 parts of hydroxylated carbon nanotubes and 48 to 112 parts of tetrahydrofuran were mixed uniformly, and 6 to 14 parts of a modifier were added at 50 to 60°C under nitrogen protection. After reacting for 12 to 30 hours, the solid product was collected, washed with tetrahydrofuran three times, and dried in an oven at 30 to 40°C for 10 to 16 hours to obtain composite modified carbon nanotubes;

[0011] (6) adding 68 to 92 parts of waste polyester bottle chips, 10 to 14 parts of modified anti-wear agent, and 3 to 5 parts of composite modified carbon nanotubes into a mixer and mixing for 20 to 30 minutes, extruding through a mixing extruder, and slicing to obtain recycled polyester chips;

[0012] (7) The regenerated polyester chips are pre-crystallized and dried at 90-100°C, melted and ejected at 275-295°C in a spinning machine, cooled, and placed in a drawing machine for drawing to 2.0-2.4 times, then curled at 150-170°C, relaxed and heat-set at 200-220°C, and cut to obtain regenerated polyester fibers.

[0013] Furthermore, the purification step in step (1) is as follows: add 1 part of the crude product to 6 parts of ethanol, stir at 100 rpm for 10 to 30 minutes, filter and collect the solid, repeat twice, add 10 parts of deionized water, stir at 90 rpm for 20 to 40 minutes, filter and collect the solid, wash with deionized water 3 times, and place in an oven at 45 to 55 ° C to dry for 10 to 16 hours.

[0014] Furthermore, the content of methylaluminoxane in the methylaluminoxane toluene solution in step (3) is 5 wt%.

[0015] Furthermore, the crystallization step in step (3) is as follows: adding 1 part of the reaction solution to 4 parts of hydrochloric acid ethanol solution, stirring at 120 rpm for 20 to 40 minutes, filtering out the solid, washing it alternately with anhydrous ethanol and deionized water for 3 times, and drying it in an oven at 45 to 55°C for 8 to 12 hours.

[0016] Furthermore, the content of hydrochloric acid in the hydrochloric acid ethanol solution is 20 wt%.

[0017] Furthermore, the temperature of the mixer in step (6) is 230-240°C.

[0018] Furthermore, the parameters of the mixing extruder in step (6) are: head temperature 280-290° C., screw speed 160-220 r / min, and extrusion pressure 6-10 MPa.

[0019] Furthermore, the cooling in step (7) is performed at a cooling air temperature of 15 to 19° C., a wind speed of 0.8 to 1.6 m / s, a wind pressure of 500 to 700 Pa, and a cooling time of 10 to 20 min.

[0020] Furthermore, the nozzle pressure of the spraying in step (7) is 0.3 to 0.5 MPa.

[0021] Furthermore, in step (7), the temperature of the drawing machine is 200-230° C., and the winding speed is 1300-1500 m / min.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The invention achieves the effects of wear resistance, antibacterial and flame retardancy by mixing recycled polyester fibers, modified wear-resistant agents and composite modified carbon nanotubes for melt spinning.

[0024] First, the modified wear-resistant agent utilizes the aldehyde group of (4-formylphenyl)phosphonic acid to combine with the amino group of 2-(3-nitroaniline)acetohydrazide to form a Schiff base structure, which can bind to the ribosomes of bacteria, prevent the bacteria from synthesizing proteins, and achieve an antibacterial effect. At the same time, the phosphorus element is introduced, and the decomposition reaction during combustion generates non-combustible products such as phosphates and phosphate esters, thereby achieving a flame retardant effect. The hydrazide structure is assisted, and a tribochemical reaction occurs during metal friction to generate nitrogen-containing compounds with low shear strength, thereby improving the wear resistance of the fiber. On this basis, the presence of the benzene ring can significantly improve the thermal stability of the wear-resistant agent and indirectly improve the flame retardant effect of the fiber; then, it dehydrates and condenses with butanediol to form a cross-linked network structure, which significantly enhances the mechanical properties of the fiber, and can deform and bend under the action of external force, thereby achieving a wear-resistant effect.

[0025] Secondly, 1,7-octadien-3-ol and octene trichlorosilane are copolymerized to form a modifier to form a cross-linked network structure, improve shear resistance, thereby increasing the stability of the connection and preliminarily improving the wear resistance of the fiber. The long-chain alkane molecules of octene trichlorosilane can enhance the adsorption stability of the molecule, thereby enhancing the wear resistance. At the same time, the presence of trichlorosilane makes it possible for the silicon element to form a glass-like film covering the fiber surface when combustion occurs, isolating the heat and oxygen from entering, and cooperating with the chlorine element to decompose and produce gas, forming a porous foam layer, thereby suppressing the combustion of the flame and achieving a flame retardant effect; then, the hydroxylated carbon nanotubes are used to attract the modifier to polymerize in situ on its surface, improving the dispersion of the carbon nanotubes while promoting the formation of an intertwined structure between the carbon nanotubes and the fiber molecules, preventing the fiber from falling off on the friction surface, thereby improving the wear resistance of the material. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the test methods of various indicators of the regenerated polyester fibers prepared in the following examples.

[0028] Breaking strength: The same weight of the embodiment and the comparative example were tested according to GB / T 14337.

[0029] Wear amount: Take the same weight of the embodiment and the comparative example, test the wear resistance of the plastic with reference to GB / T 3960, and record the wear mass.

[0030] Antibacterial rate: Take the same weight of the embodiment and the comparative example, and make the composite fiber non-woven fabric of the same specification (weight 400g / m 2 ) fabrics, tested according to GB / T 20944.3.

[0031] Limiting oxygen index: Take the same weight of the embodiment and the comparative example, and make the composite fiber non-woven fabric of the same specification (weight 400g / m 2 ) fabrics, tested according to ISO4589-2.

[0032] Example 1: (1) 10 parts of (4-formylphenyl)phosphonic acid, 8 parts of 2-(3-nitroaniline)acetohydrazide, and 96 parts of anhydrous ethanol were mixed uniformly, heated to 74°C, and stirred at 100 rpm for 5 hours to obtain a crude product. 1 part of the crude product was added to 6 parts of ethanol, stirred at 100 rpm for 10 minutes, and the solid was filtered out. This was repeated twice. 10 parts of deionized water was added, stirred at 90 rpm for 20 minutes, and the solid was filtered out. The solid was washed three times with deionized water and dried in a 45°C oven for 10 hours to obtain a composite agent.

[0033] (2) 3 parts of the composite agent, 7 parts of butanediol, and 80 parts of toluene were mixed evenly, heated to 100°C, stirred at 90 rpm for 6 hours, cooled to 25°C, and concentrated at a vacuum degree of -0.1 MPa and 40°C for 4 hours to obtain a modified wear-resistant agent;

[0034] (3) Under a nitrogen atmosphere, 3 parts of 1,7-octadien-3-ol, 8 parts of octene trichlorosilane, and 85 parts of toluene were mixed uniformly, the temperature was raised to 50°C, 5 parts of 5 wt% methylaluminoxane toluene solution were added dropwise at a rate of 1 drop / s, and the mixture was stirred at 80 rpm for 4 h to obtain a reaction solution. 1 part of the reaction solution was added to 4 parts of 20 wt% hydrochloric acid ethanol solution, and the mixture was stirred at 120 rpm for 20 min. The solid was filtered and washed three times with anhydrous ethanol and deionized water alternately, and dried in an oven at 45°C for 8 h to obtain a modifier;

[0035] (4) 14 parts of carbon nanotubes were placed in a container, 32 parts of 15 wt% sulfuric acid and 28 parts of 15 wt% nitric acid were added, ultrasonicated at 20°C for 1.5 hours, heated to 80°C for 1 hour, filtered to obtain the solid, washed three times with deionized water, and dried in an oven at 45°C for 6 hours to obtain hydroxylated carbon nanotubes;

[0036] (5) 12 parts of hydroxylated carbon nanotubes and 48 parts of tetrahydrofuran were mixed evenly, and 6 parts of modifier were added at 50°C under nitrogen protection. After reacting for 12 hours, the solid product was collected, washed with tetrahydrofuran three times, and dried in an oven at 30°C for 10 hours to obtain composite modified carbon nanotubes;

[0037] (6) 68 parts of waste polyester bottle chips, 10 parts of modified anti-wear agent, and 3 parts of composite modified carbon nanotubes were added to a mixer and mixed at 230°C for 20 minutes. The chips were extruded through a mixing extruder with a head temperature of 280°C, a screw speed of 160 r / min, and an extrusion pressure of 6 MPa to obtain recycled polyester chips.

[0038] (7) The recycled polyester chips were pre-crystallized and dried at 90°C, melted at 275°C in a spinning machine, ejected at a pressure of 0.3 MPa, cooled for 10 min at a cooling air temperature of 15°C, a wind speed of 0.8 m / s, and a wind pressure of 500 Pa, and placed in a drawing machine for drawing to 2.0 times, wherein the drawing machine temperature was 200°C and the winding speed was 1300 m / min, and then curled at 150°C, relaxed and heat-set at 200°C, and cut to obtain recycled polyester fibers.

[0039] Example 2: (1) 15 parts of (4-formylphenyl)phosphonic acid, 12 parts of 2-(3-nitroaniline)acetohydrazide, and 144 parts of anhydrous ethanol were mixed uniformly, heated to 77°C, and stirred at 100 rpm for 6 hours to obtain a crude product. 1 part of the crude product was added to 6 parts of ethanol, stirred at 100 rpm for 20 minutes, and the solid was filtered out. This was repeated twice. 10 parts of deionized water was added, stirred at 90 rpm for 30 minutes, and the solid was filtered out. The solid was washed three times with deionized water and dried in a 50°C oven for 13 hours to obtain a composite agent.

[0040] (2) 6 parts of the composite agent, 14 parts of butanediol, and 160 parts of toluene were mixed evenly, heated to 105°C, stirred at 90 rpm for 7 hours, cooled to 25°C, and concentrated at a vacuum degree of -0.1 MPa and 40°C for 5 hours to obtain a modified wear-resistant agent;

[0041] (3) Under a nitrogen atmosphere, 5 parts of 1,7-octadien-3-ol, 10 parts of octene trichlorosilane, and 115 parts of toluene were mixed uniformly, heated to 55°C, and 7 parts of a 5 wt% methylaluminoxane toluene solution were added dropwise at a rate of 1 drop / s. The mixture was stirred at 80 rpm for 6 h to obtain a reaction solution. 1 part of the reaction solution was added to 4 parts of a 20 wt% hydrochloric acid ethanol solution, stirred at 120 rpm for 30 min, and the solid was filtered and washed three times with anhydrous ethanol and deionized water alternately. The solid was dried in an oven at 50°C for 10 h to obtain a modifier.

[0042] (4) 18 parts of carbon nanotubes were placed in a container, 41 parts of 15 wt% sulfuric acid and 37 parts of 15 wt% nitric acid were added, ultrasonicated at 25°C for 2.0 h, heated to 90°C for 2 h, filtered to obtain the solid, washed three times with deionized water, and dried in an oven at 50°C for 8 h to obtain hydroxylated carbon nanotubes;

[0043] (5) 24 parts of hydroxylated carbon nanotubes and 80 parts of tetrahydrofuran were mixed evenly, and 10 parts of a modifier was added at 55°C under nitrogen protection. After reacting for 21 hours, the solid product was collected, washed with tetrahydrofuran three times, and dried in an oven at 35°C for 13 hours to obtain composite modified carbon nanotubes;

[0044] (6) 80 parts of waste polyester bottle chips, 12 parts of modified anti-wear agent, and 4 parts of composite modified carbon nanotubes were added to a mixer and mixed at 235°C for 25 minutes. The chips were extruded through a mixing extruder with a head temperature of 285°C, a screw speed of 190 r / min, and an extrusion pressure of 8 MPa, and sliced ​​to obtain recycled polyester chips;

[0045] (7) The recycled polyester chips were pre-crystallized and dried at 95°C, melted at 285°C in a spinning machine, ejected at a pressure of 0.4 MPa, cooled for 15 min at a cooling air temperature of 17°C, a wind speed of 1.2 m / s, and a wind pressure of 600 Pa, and placed in a drawing machine for drawing to 2.2 times, wherein the drawing machine temperature was 215°C and the winding speed was 1400 m / min, and then curled at 160°C, relaxed and heat-set at 210°C, and cut to obtain recycled polyester fibers.

[0046] Example 3: (1) 20 parts of (4-formylphenyl)phosphonic acid, 16 parts of 2-(3-nitroaniline)acetohydrazide, and 192 parts of anhydrous ethanol were mixed uniformly, heated to 80°C, and stirred at 100 rpm for 7 hours to obtain a crude product. 1 part of the crude product was added to 6 parts of ethanol, stirred at 100 rpm for 30 minutes, and the solid was filtered out. This was repeated twice. 10 parts of deionized water was added, and the mixture was stirred at 90 rpm for 40 minutes. The solid was filtered out, washed three times with deionized water, and dried in a 55°C oven for 16 hours to obtain a composite agent.

[0047] (2) 9 parts of the composite agent, 21 parts of butanediol, and 240 parts of toluene were mixed uniformly, heated to 110°C, stirred at 90 rpm for 8 hours, cooled to 25°C, and concentrated at a vacuum degree of -0.1 MPa and 40°C for 6 hours to obtain a modified wear-resistant agent;

[0048] (3) Under a nitrogen atmosphere, 7 parts of 1,7-octadien-3-ol, 12 parts of octene trichlorosilane, and 145 parts of toluene were mixed uniformly, the temperature was raised to 60°C, 9 parts of 5 wt% methylaluminoxane toluene solution were added dropwise at a rate of 1 drop / s, and the mixture was stirred at 80 rpm for 8 h to obtain a reaction solution. 1 part of the reaction solution was added to 4 parts of 20 wt% hydrochloric acid ethanol solution, and the mixture was stirred at 120 rpm for 40 min. The solid was filtered and washed three times with anhydrous ethanol and deionized water alternately, and dried in an oven at 55°C for 12 h to obtain a modifier;

[0049] (4) 22 parts of carbon nanotubes were placed in a container, 50 parts of 15 wt% sulfuric acid and 46 parts of 15 wt% nitric acid were added, ultrasonicated at 30°C for 2.5 hours, heated to 100°C for reaction for 3 hours, filtered to obtain the solid, washed three times with deionized water, and dried in an oven at 55°C for 10 hours to obtain hydroxylated carbon nanotubes;

[0050] (5) 36 parts of hydroxylated carbon nanotubes and 112 parts of tetrahydrofuran were mixed evenly, and 14 parts of a modifier was added at 60°C under nitrogen protection. After reacting for 30 hours, the solid product was collected, washed with tetrahydrofuran three times, and dried in an oven at 40°C for 16 hours to obtain composite modified carbon nanotubes;

[0051] (6) 92 parts of waste polyester bottle chips, 14 parts of modified anti-wear agent, and 5 parts of composite modified carbon nanotubes were added to a mixer and mixed at 240°C for 30 minutes. The chips were extruded through a mixing extruder with a head temperature of 290°C, a screw speed of 220 r / min, and an extrusion pressure of 10 MPa, and sliced ​​to obtain recycled polyester chips;

[0052] (7) The recycled polyester chips were pre-crystallized and dried at 100°C, melted at 295°C in a spinning machine, ejected at a pressure of 0.5 MPa, cooled for 20 min at a cooling air temperature of 19°C, a wind speed of 1.6 m / s, and a wind pressure of 700 Pa, and placed in a drawing machine for drawing to 2.4 times, wherein the drawing machine temperature was 230°C and the winding speed was 1500 m / min, and then curled at 170°C, relaxed and heat-set at 220°C, and cut to obtain recycled polyester fibers.

[0053] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that step (1) is omitted, and step (2) is changed to: 6 parts of 2-(3-nitroaniline)acetohydrazide, 14 parts of butanediol, and 160 parts of toluene are mixed uniformly, heated to 105°C, stirred at 90 rpm for 7 hours, cooled to 25°C, and concentrated at a vacuum degree of -0.1 MPa and 40°C for 5 hours to obtain a modified anti-wear agent. The remaining steps are the same as those in Example 2.

[0054] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that step (1) is omitted, and step (2) is changed to: 6 parts of (4-formylphenyl)phosphonic acid, 14 parts of butanediol, and 160 parts of toluene are uniformly mixed, heated to 105°C, stirred at 90 rpm for 7 hours, cooled to 25°C, and concentrated at a vacuum degree of -0.1 MPa and 40°C for 5 hours to obtain a modified anti-wear agent. The remaining steps are the same as in Example 2.

[0055] Comparative Example 3: Comparative Example 3 differs from Example 2 in that step (2) is omitted and step (6) is modified as follows: 80 parts of waste polyester bottle flakes, 12 parts of a compounding agent, and 4 parts of composite modified carbon nanotubes are added to a mixer and mixed at 235°C for 25 minutes. The mixture is then extruded through a mixing extruder at a feed head temperature of 285°C, a screw speed of 190 r / min, and an extrusion pressure of 8 MPa, and sliced ​​to produce recycled polyester chips. The remaining steps are the same as in Example 2.

[0056] Comparative Example 4: Comparative Example 4 differs from Example 2 in that steps (1) and (2) are omitted, and step (6) is modified as follows: 80 parts of waste polyester bottle flakes, 2 parts of (4-formylphenyl)phosphonic acid, 1 part of 2-(3-nitroaniline)acetohydrazide, 7 parts of butanediol, and 4 parts of composite modified carbon nanotubes are added to a mixer and mixed at 235° C. for 25 minutes. The mixture is then extruded through a mixing extruder at a head temperature of 285° C., a screw speed of 190 r / min, and an extrusion pressure of 8 MPa, and sliced ​​to produce recycled polyester chips. The remaining steps are the same as those in Example 2.

[0057] Comparative Example 5: The difference between Comparative Example 5 and Example 2 is that step (3) is omitted. Step (5) is modified as follows: 24 parts of hydroxylated carbon nanotubes and 80 parts of tetrahydrofuran are uniformly mixed, 10 parts of octenetrichlorosilane are added at 55°C under nitrogen protection, and the reaction is continued for 21 hours. The solid product is collected, washed three times with tetrahydrofuran, and dried in an oven at 35°C for 13 hours to obtain composite modified carbon nanotubes. The remaining steps are the same as those in Example 2.

[0058] Comparative Example 6: The difference between Comparative Example 6 and Example 2 is that step (3) is omitted, and step (5) is changed to: 24 parts of hydroxylated carbon nanotubes and 80 parts of tetrahydrofuran are mixed uniformly, and 10 parts of 1,7-octadien-3-ol are added at 55°C under nitrogen protection. After reacting for 21 hours, the solid product is collected, washed three times with tetrahydrofuran, and dried in an oven at 35°C for 13 hours to obtain composite modified carbon nanotubes. The remaining steps are the same as those in Example 2.

[0059] Effect Examples

[0060] Table 1 below shows the performance analysis results of the regenerated polyester fibers of Examples 1 to 3 of the present invention and Comparative Examples 1 to 6.

[0061] Table 1

[0062]

[0063] From the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Example 1, it can be found that the phosphorus element is introduced by using (4-formylphenyl)phosphonic acid, and the decomposition reaction during combustion generates non-combustible products such as phosphates and phosphate ester salts, thereby achieving a flame retardant effect; from the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Example 2, it can be found that through the hydrazide structure in 2-(3-nitroaniline)acetohydrazide, a tribochemical reaction occurs during metal friction to generate nitrogen-containing compounds with low shear strength, thereby improving the wear resistance of the fiber. At the same time, the presence of the benzene ring can significantly improve the thermal stability of the wear-resistant agent and improve the flame retardant effect of the fiber; from the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Example 3, it can be found that by dehydration condensation with butanediol, a cross-linked network structure is formed, which significantly enhances the mechanical properties of the fiber, and can be deformed and bent under the action of external force, thereby achieving a wear-resistant effect; from the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Example 4, it can be found that Now, the aldehyde group of (4-formylphenyl)phosphonic acid is combined with the amino group of 2-(3-nitroaniline)acetohydrazide to form a Schiff base structure, which can bind to the ribosome of bacteria, prevent the bacteria from synthesizing protein, and have an antibacterial effect; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 5, it can be found that the use of 1,7-octadien-3-ol to participate in the polymerization reaction can form a cross-linked network structure, improve shear resistance, increase connection stability, and improve fiber wear resistance; from the comparison of the experimental data of Examples 1, 2, and 3 with Comparative Example 6, it can be found that the long-chain alkane molecules of octene trichlorosilane can enhance the adsorption stability of the molecule and enhance the wear resistance. At the same time, the presence of trichlorosilane makes it possible that when combustion occurs, the silicon element is heated to form a glass-like film covering the fiber surface, isolating heat and oxygen from entering, and cooperates with the chlorine element to decompose and produce gas to form a porous foam layer, which can suppress the combustion of the flame and achieve a flame retardant effect.

[0064] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A method for preparing regenerated polyester fiber, characterized in that: The method comprises the following preparation steps: (1) 10-20 parts of (4-formylphenyl)phosphonic acid, 8-16 parts of 2-(3-nitroaniline)acetohydrazide, and 96-192 parts of anhydrous ethanol were mixed uniformly, heated to 74-80°C, and stirred at 100 rpm for 5-7 hours to obtain a crude product, which was purified to obtain a composite agent; (2) 3-9 parts of the composite agent, 7-21 parts of butanediol, and 80-240 parts of toluene were mixed uniformly, heated to 100-110°C, stirred at 90 rpm for 6-8 hours, cooled to 25°C, and concentrated at a vacuum degree of -0.1 MPa and 40°C for 4-6 hours to obtain a modified wear-resistant agent; (3) Under a nitrogen atmosphere, 3 to 7 parts of 1,7-octadien-3-ol, 8 to 12 parts of octene trichlorosilane, and 85 to 145 parts of toluene were mixed uniformly, the temperature was raised to 50 to 60° C., 5 to 9 parts of methylaluminoxane toluene solution were added dropwise at a rate of 1 drop / s, and the mixture was stirred at 80 rpm for 4 to 8 hours to obtain a reaction solution, which was crystallized to obtain a modifier; (4) placing 14 to 22 parts of carbon nanotubes in a container, adding 32 to 50 parts of 15 wt% sulfuric acid and 28 to 46 parts of 15 wt% nitric acid, ultrasonically treating at 20 to 30°C for 1.5 to 2.5 hours, heating to 80 to 100°C for reaction for 1 to 3 hours, filtering the solid, washing it three times with deionized water, and drying it in an oven at 45 to 55°C for 6 to 10 hours to obtain hydroxylated carbon nanotubes; (5) 12 to 36 parts of hydroxylated carbon nanotubes and 48 to 112 parts of tetrahydrofuran were mixed uniformly, and 6 to 14 parts of a modifier were added at 50 to 60°C under nitrogen protection. After reacting for 12 to 30 hours, the solid product was collected, washed with tetrahydrofuran three times, and dried in an oven at 30 to 40°C for 10 to 16 hours to obtain composite modified carbon nanotubes; (6) adding 68 to 92 parts of waste polyester bottle chips, 10 to 14 parts of modified anti-wear agent, and 3 to 5 parts of composite modified carbon nanotubes into a mixer and mixing for 20 to 30 minutes, extruding through a mixing extruder, and slicing to obtain recycled polyester chips; (7) The regenerated polyester chips are pre-crystallized and dried at 90-100°C, melted and ejected at 275-295°C in a spinning machine, cooled, and placed in a drawing machine for drawing to 2.0-2.4 times, then curled at 150-170°C, relaxed and heat-set at 200-220°C, and cut to obtain regenerated polyester fibers.

2. The method for preparing regenerated polyester fiber according to claim 1, characterized in that: The purification step in step (1) is as follows: add 1 part of the crude product to 6 parts of ethanol, stir at 100 rpm for 10 to 30 minutes, filter and collect the solid, repeat twice, add 10 parts of deionized water, stir at 90 rpm for 20 to 40 minutes, filter and collect the solid, wash with deionized water 3 times, and place in an oven at 45 to 55 ° C to dry for 10 to 16 hours.

3. The method for preparing regenerated polyester fiber according to claim 1, characterized in that: The content of methylaluminoxane in the methylaluminoxane toluene solution in step (3) is 5 wt%.

4. The method for preparing regenerated polyester fiber according to claim 1, wherein: The crystallization step in step (3) is as follows: add 1 part of the reaction solution to 4 parts of hydrochloric acid ethanol solution, stir at 120 rpm for 20 to 40 minutes, filter out the solid, wash it alternately with anhydrous ethanol and deionized water for 3 times, and dry it in an oven at 45 to 55°C for 8 to 12 hours.

5. The method for preparing regenerated polyester fiber according to claim 4, characterized in that: The content of hydrochloric acid in the hydrochloric acid ethanol solution is 20 wt %.

6. The method for preparing regenerated polyester fiber according to claim 1, characterized in that: The mixer temperature in step (6) is 230-240°C.

7. The method for preparing regenerated polyester fiber according to claim 1, characterized in that: The parameters of the mixing extruder in step (6) are: head temperature 280-290° C., screw speed 160-220 r / min, and extrusion pressure 6-10 MPa.

8. The method for preparing regenerated polyester fiber according to claim 1, characterized in that: The cooling in step (7) is performed at a cooling air temperature of 15 to 19° C., a wind speed of 0.8 to 1.6 m / s, a wind pressure of 500 to 700 Pa, and a cooling time of 10 to 20 min.

9. The method for preparing regenerated polyester fiber according to claim 1, characterized in that: The nozzle pressure of the spray in step (7) is 0.3 to 0.5 MPa.

10. The method for preparing regenerated polyester fiber according to claim 1, characterized in that: The temperature of the drawing machine in step (7) is 200-230° C. and the winding speed is 1300-1500 m / min.

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