A method for preparing multifunctional triporous fibers from recycled polyester

Abstract

This invention relates to a method for preparing multifunctional triporous fibers from recycled polyester, belonging to the field of synthetic fiber technology. The invention first synthesizes a self-made flame retardant containing double bonds using DOPO as a base, then prepares quaternized vinyl imidazole-modified acrylate-based self-made antistatic particles. These two are then blended with recycled PET chips grafted with double-bonded monomers and an initiator, followed by melt spinning using a triangular spinneret to obtain the target fiber. The three-dimensional cross-linked network, the dispersion and toughening of functional particles, the rigid reinforcement of the flame retardant, and the formation of the triporous fiber synergistically enhance the fiber's mechanical properties. The polar groups of the flame retardant form ion pairs with the quaternary ammonium salt, effectively improving ionic conductivity and imparting good antistatic properties to the fiber. The charring and heat insulation of the flame retardant, combined with the gas-phase flame retardancy achieved by the antistatic particles releasing hydrogen halides to capture free radicals, synergistically achieve excellent flame retardant effects. The fiber prepared by this invention exhibits excellent mechanical properties, antistatic properties, and flame retardant properties.

Description

Technical Field

[0001] This invention relates to the field of synthetic fiber technology, specifically to a method for preparing multifunctional triporous fibers from recycled polyester. Background Technology

[0002] With the rapid development of the polyester resource recycling industry, melt spinning of recycled PET to produce fibers has become an important way to achieve resource recycling. However, the mechanical properties of recycled PET chips have decreased significantly after multiple processing, and their single function can no longer meet the needs of high-end textile fields for multiple properties such as flame retardancy and antistatic properties.

[0003] In existing technologies, the multifunctional modification of recycled polyester fibers mostly employs physical blending with commercially available flame retardants and antistatic agents. This method suffers from poor compatibility between the functional components and the PET matrix, leading to easy migration and precipitation, resulting in poor fiber functional stability and further deterioration of mechanical properties. Simultaneously, conventionally spun fibers have a small specific surface area, uneven melt cooling, and incomplete crystallization, making it difficult to achieve a synergistic improvement in both mechanical and functional properties. Furthermore, existing flame retardant and antistatic modifications are mostly single-effect modifications, failing to fully utilize their synergistic effect and thus failing to achieve excellent comprehensive mechanical, flame retardant, and antistatic properties, limiting the high-end applications of recycled polyester fibers. Therefore, developing a multifunctional recycled polyester fiber with synergistic performance and good stability is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing multifunctional triporous fibers from recycled polyester, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a recycled polyester multifunctional triporous fiber, comprising the following steps: (1) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-naphthoquinone and tetrahydrofuran were mixed in a mass ratio of 2~3:1~2:20. The mixture was stirred and reacted at 50~60℃ for 4~6h under a nitrogen atmosphere. After naturally cooling to 5℃, 0.8~0.9 times the mass of 1,4-naphthoquinone acryloyl chloride and 1~1.2 times the mass of 1,4-naphthoquinone acid binder were slowly added dropwise. The mixture was stirred and kept warm at 200rpm for 1h. The temperature was then raised to 30~40℃ and stirred and reacted for 2~4h. The mixture was filtered and concentrated under reduced pressure. After vacuum filtration, the mixture was washed three times with petroleum ether and dried under vacuum at 50℃ for 12h to obtain the self-made flame retardant. (2) Bromoalkyl, 1-vinylimidazolium and anhydrous ethanol are mixed in a mass ratio of 2~3:1~1.5:10 and stirred and refluxed at 70~90℃ for 8~10h. After filtration and washing, the mixture is dried under vacuum at 40℃ for 24h to obtain a quaternized intermediate. Then, polymer particles obtained by emulsion polymerization of acrylate monomers, the quaternized intermediate, the catalyst and toluene are mixed in a mass ratio of 5~6:1~2:0.1:10 and stirred and refluxed at 100~110℃ for 5~7h. After filtration and washing, the mixture is dried at 90℃ and vacuum degree -0.09MPa for 12h to obtain self-made antistatic particles. (3) Modified PET grafted with glycidyl methacrylate, self-made flame retardant, self-made antistatic particles and initiator are mixed at a mass ratio of 80~90:5~10:4~8:0.5, mixed at high speed for 30 minutes, melt spun through a spinneret with three holes arranged in a triangular pattern, and then stretched, shaped and wound to obtain recycled polyester multifunctional three-hole fiber.

[0006] Furthermore, the rate of slow addition in step (1) is 1 mL / min.

[0007] Furthermore, the acid-binding agent in step (1) is triethylamine.

[0008] Furthermore, the bromoalkane mentioned in step (2) is: bromotetradecane.

[0009] Furthermore, the acrylate monomers in step (2) are methyl methacrylate and butyl acrylate.

[0010] Furthermore, the polymer particles in step (2) have a particle size of 300~500nm.

[0011] Furthermore, the catalyst in step (2) is p-toluenesulfonic acid.

[0012] Furthermore, the PET mentioned in step (3) is: recycled PET chips with an intrinsic viscosity of 0.70 dL / g.

[0013] Furthermore, the initiator in step (3) is dicumyl peroxide.

[0014] Furthermore, the recycled polyester multifunctional triporous fiber mentioned in step (3) has a single filament diameter of 12 μm and a porosity of 20%.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: This invention combines a self-made flame retardant and a self-made antistatic particle with modified PET and melt-spun to obtain a multifunctional recycled polyester, achieving excellent mechanical properties, antistatic properties, and flame retardant properties.

[0016] This invention first involves nucleophilic addition of DOPO and 1,4-naphthoquinone, followed by esterification with acryloyl chloride to obtain a self-made flame retardant containing double bonds. Then, a quaternization reaction is performed between a brominated hydrocarbon and vinylimidazolium, followed by esterification grafting onto the surface of a polymer obtained by emulsion polymerization of acrylate monomers to obtain self-made antistatic particles containing double bonds. These two self-made materials are then blended with recycled PET chips grafted with esterified double-bonded monomers and an initiator, and melt-spun using a triangular spinneret to obtain multifunctional three-porous recycled polyester fibers. The three-dimensional cross-linked polymer network enhances the fiber's tensile strength while preventing physical separation of functional components from the matrix. Furthermore, the dispersion and toughening effect of the self-made antistatic particles, the rigid group reinforcement of the self-made flame retardant, and the increased porosity of the three-porous fibers contribute to the fiber's overall strength. The specific surface area allows for a more uniform melt cooling rate during melt spinning, resulting in a more complete crystalline zone. These three factors work synergistically to endow the fiber with excellent mechanical properties. The polar groups in the self-made flame retardant can form ion pairs with the quaternary ammonium salt groups, increasing the concentration of free ions and improving ion conductivity, thus giving the fiber good antistatic properties. The self-made flame retardant can form a dense and continuous char layer during high-temperature combustion, effectively blocking heat transfer to the interior. Furthermore, the conjugated naphthalene ring can promote the aromatization and graphitization of the char layer, improving its thermal stability and density, further enhancing the flame retardant effect. At the same time, the self-made antistatic particles decompose at high temperatures to generate hydrogen halide gas, which can capture active free radicals during combustion and inhibit chain combustion reactions in the gas phase. The synergistic effect of these two factors endows the fiber with excellent flame retardant properties. Detailed Implementation

[0017] 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.

[0018] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the recycled polyester multifunctional triporous fiber produced in the following embodiments are as follows: Mechanical property testing: The fibers prepared in Examples 1-5 and Comparative Examples 1-6 were tested for mechanical properties according to GB / T14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments". The specific test conditions were as follows: the pre-tension value was set to 5cN, the clamping length was set to 250mm, the tensile rate was set to 250mm / min, and each group of fiber samples was tested 10-20 times until stable data was obtained. The CV value was required to be kept within 15%.

[0019] Flame retardant performance test: The oxygen index method was used. Under the specified test conditions, a mixture of oxygen and nitrogen was introduced, and the fiber samples prepared in Examples 1-5 and Comparative Examples 1-6 were ignited. The minimum oxygen concentration required to just maintain the combustion of the sample was measured and expressed as the oxygen index.

[0020] Antistatic performance test: The surface resistivity of the fibers prepared in Examples 1-5 and Comparative Examples 1-6 was tested according to standard GB / T12703.4-2010.

[0021] Example 1; (1) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-naphthoquinone and tetrahydrofuran were mixed in a mass ratio of 2:1:20. Under a nitrogen atmosphere, the mixture was stirred at 50°C and 300 rpm for 4 h. After naturally cooling to 5°C, 0.8 times the mass of 1,4-naphthoquinone acryloyl chloride and 1 times the mass of 1,4-naphthoquinone triethylamine were slowly added dropwise at a rate of 1 mL / min. The mixture was stirred at 200 rpm and kept warm for 1 h. Then, the temperature was raised to 30°C and stirred for 2 h. The triethylamine hydrochloride solid was removed by filtration. The filtrate was concentrated under reduced pressure at 40°C and -0.09 MPa on a rotary evaporator to remove most of the tetrahydrofuran. The concentrate was poured into excess cold petroleum ether, and the solid was precipitated and filtered. The solid was washed three times with cold petroleum ether and dried at 50°C and -0.09 MPa for 12 h to obtain the self-made flame retardant. (2) Bromotetradecane, 1-vinylimidazole and anhydrous ethanol were mixed in a mass ratio of 2:1:10 and refluxed at 70°C and 300 rpm for 8 h. After cooling to room temperature, the reaction solution was poured into excess anhydrous diethyl ether and stirred vigorously at 1500 rpm, resulting in the precipitation of a white viscous solid. The supernatant was discarded, and the solid was washed three times with anhydrous diethyl ether and then dried at 40°C and a vacuum of -0.09 MPa for 24 h to obtain the quaternized intermediate. (3) Sodium dodecylbenzenesulfonate and deionized water were mixed at a mass ratio of 0.05:10 and stirred at 800 rpm for 2-4 h at 60 °C to obtain an aqueous emulsion; methyl methacrylate, butyl acrylate and divinylbenzene were mixed at a mass ratio of 6:1:1:10 and stirred at 200 rpm for 1 h at room temperature, and added to the same volume of aqueous emulsion, and stirred at 500 rpm for 30 min for pre-emulsification to obtain a pre-emulsion; ammonium persulfate was added at a mass ratio of 0.4 times that of sodium dodecylbenzenesulfonate. Mix with 10 times the amount of deionized water containing ammonium persulfate, and add dropwise at 2 mL / min to the milky white pre-emulsion prepared above. Heat to 60°C and stir at 300 rpm for 5 h. Add 10 wt% sodium chloride aqueous solution to break the emulsion, and continue stirring at 60°C for 30 min. Filter and wash three times with 50°C deionized water, then wash once with room temperature deionized water. Dry at 50°C and vacuum degree -0.09 MPa for 6-8 h to obtain polymer particles with a particle size of 300-500 nm. (4) The polymer particles, quaternization intermediate, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 5:1:0.1:10 and stirred and refluxed at 100°C and 500 rpm for 5 h. The mixture was filtered and the filter cake was washed twice with toluene to remove unreacted quaternary ammonium salt and catalyst. The mixture was then washed once with anhydrous ethanol to remove residual toluene. The mixture was filtered until no liquid dripped from the filter cake and dried at 90°C and vacuum degree -0.09 MPa for 12 h to obtain the self-made antistatic particles. (5) Mix recycled PET chips with an intrinsic viscosity of 0.70 dL / g, glycidyl methacrylate and stannous octoate in a mass ratio of 100:5:0.3, put them into a high-speed mixer, adjust the mixing temperature to 120℃, the speed to 2000 rpm, mix for 30 min to make the raw materials uniformly mixed, and feed them into a twin-screw extruder. Set the temperature of each section of the extruder as follows: feed section 250℃, melt section 260℃, die head section 255℃, screw speed 180 rpm, connect the extruder outlet to a pelletizer, and extrude and pelletize to obtain modified PET with a particle size of 3 mm. (6) Modified PET, self-made flame retardant, self-made antistatic particles, and dicumyl peroxide are mixed in a mass ratio of 80:5:4:0.5 and placed in a high-speed mixer. The mixing temperature is adjusted to 120℃ and the rotation speed is 2000rpm. The mixture is mixed for 30min to ensure uniform dispersion of the raw materials and obtain a blend. The blend is then melt-spun through a spinneret with a 0.3mm orifice and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, and spinneret temperature 280℃. The spinning machine is turned on and preheated for 30min to ensure complete melting of the blend. The melt pressure is adjusted to 1. At 5 MPa, the spinneret assembly is turned on, and the spinneret rate is controlled. At the same time, the cooling air is turned on at a temperature of 25℃ and a speed of 0.8 m / s to cool and set the molten filament after spinning. The cooled and set fiber is then sent to the stretching device, where the stretching temperature is set to 85℃ and the stretching ratio is 3.5 times to perform stretching treatment and improve the mechanical properties of the fiber. The stretched fiber is then sent to the setting device, where the setting temperature is set to 120℃ and the setting time is 5 seconds. Then it is sent to the winding device, where the winding speed is adjusted to 2800 m / min to perform winding, resulting in a multifunctional three-porous recycled polyester fiber with a monofilament diameter of 12 μm and a porosity of 20%.

[0022] Example 2; (1) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-naphthoquinone and tetrahydrofuran were mixed in a mass ratio of 2.2:1.2:20. The mixture was stirred at 52°C and 300 rpm for 4.5 h under a nitrogen atmosphere. After naturally cooling to 5°C, 0.8~0.9 times the mass of 1,4-naphthoquinone acryloyl chloride and 1.05 times the mass of 1,4-naphthoquinone triethylamine were slowly added dropwise at a rate of 1 mL / min. The mixture was stirred at 200 rpm and kept warm for 1 h. The temperature was then raised to 32°C and stirred for 2.5 h. The triethylamine hydrochloride solid was removed by filtration. The filtrate was concentrated under reduced pressure at 42°C and -0.09 MPa in a rotary evaporator to remove most of the tetrahydrofuran. The concentrate was poured into an excess of cold petroleum ether, the solid was precipitated and filtered, the solid was washed three times with cold petroleum ether, and dried at 50°C and vacuum degree -0.09MPa for 12h to obtain the self-made flame retardant. (2) Bromotetradecane, 1-vinylimidazolium and anhydrous ethanol were mixed in a mass ratio of 2.2:1.2:10 and refluxed at 75°C and 300 rpm for 8.5 h. After cooling to room temperature, the reaction solution was poured into excess anhydrous diethyl ether and stirred vigorously at 1500 rpm, resulting in the precipitation of a white viscous solid. The supernatant was discarded, and the solid was washed three times with anhydrous diethyl ether and then dried at 40°C and a vacuum of -0.09 MPa for 24 h to obtain the quaternized intermediate. (3) Sodium dodecylbenzenesulfonate and deionized water were mixed at a mass ratio of 0.05:10 and stirred at 800 rpm for 2.5 h at 60 °C to obtain an aqueous emulsion; methyl methacrylate, butyl acrylate and divinylbenzene were mixed at a mass ratio of 6.5:1.5:1:10 and stirred at 200 rpm for 1 h at room temperature, and added to the same volume of aqueous emulsion, and stirred at 500 rpm for 30 min for pre-emulsification to obtain a pre-emulsion; 0.45 times the mass of sodium dodecylbenzenesulfonate was added. Ammonium persulfate was mixed with 10 times its volume of deionized water and added dropwise at 2 mL / min to the milky white pre-emulsion prepared above. The mixture was heated to 65 °C and stirred at 300 rpm for 5.5 h. 10 wt% sodium chloride aqueous solution was added to break the emulsion. The mixture was stirred at 62 °C for 30 min. The mixture was filtered and washed three times with 50 °C deionized water and once with room temperature deionized water. The mixture was then dried at 50 °C and a vacuum of -0.09 MPa for 6 h to obtain polymer particles with a particle size of 350 nm. (4) The polymer particles, quaternization intermediate, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 5.2:1.2:0.1:10 and stirred and refluxed at 102℃ and 500rpm for 5.5h. The mixture was filtered and the filter cake was washed twice with toluene to remove unreacted quaternary ammonium salt and catalyst. The mixture was then washed once with anhydrous ethanol to remove residual toluene. The mixture was filtered until no liquid dripped from the filter cake and dried at 90℃ and vacuum degree -0.09MPa for 12h to obtain the self-made antistatic particles. (5) Mix recycled PET chips with an intrinsic viscosity of 0.70 dL / g, glycidyl methacrylate and stannous octoate in a mass ratio of 100:5:0.3, put them into a high-speed mixer, adjust the mixing temperature to 120℃, the speed to 2000 rpm, mix for 30 min to make the raw materials uniformly mixed, and feed them into a twin-screw extruder. Set the temperature of each section of the extruder as follows: feed section 250℃, melt section 260℃, die head section 255℃, screw speed 180 rpm, connect the extruder outlet to a pelletizer, and extrude and pelletize to obtain modified PET with a particle size of 3 mm. (6) Modified PET, self-made flame retardant, self-made antistatic particles, and dicumyl peroxide are mixed in a mass ratio of 82:6:5:0.5 and placed in a high-speed mixer. The mixing temperature is adjusted to 120℃ and the rotation speed is 2000rpm. The mixture is mixed for 30min to ensure uniform dispersion of the raw materials and obtain a blend. The blend is then melt-spun through a spinneret with a 0.3mm orifice and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, and spinneret temperature 280℃. The spinning machine is turned on and preheated for 30min to ensure complete melting of the blend. The melt pressure is adjusted to 1. At 5 MPa, the spinneret assembly is turned on, and the spinneret rate is controlled. At the same time, the cooling air is turned on at a temperature of 25℃ and a speed of 0.8 m / s to cool and set the molten filament after spinning. The cooled and set fiber is then sent to the stretching device, where the stretching temperature is set to 85℃ and the stretching ratio is 3.5 times to perform stretching treatment and improve the mechanical properties of the fiber. The stretched fiber is then sent to the setting device, where the setting temperature is set to 120℃ and the setting time is 5 seconds. Then it is sent to the winding device, where the winding speed is adjusted to 2800 m / min to perform winding, resulting in a multifunctional three-porous recycled polyester fiber with a monofilament diameter of 12 μm and a porosity of 20%.

[0023] Example 3; (1) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-naphthoquinone and tetrahydrofuran were mixed in a mass ratio of 2.5:1.5:20. The mixture was stirred at 55°C and 300 rpm for 5 h under a nitrogen atmosphere. After naturally cooling to 5°C, 0.85 times the mass of 1,4-naphthoquinone acryloyl chloride and 1.1 times the mass of 1,4-naphthoquinone triethylamine were slowly added dropwise at a rate of 1 mL / min. The mixture was stirred at 200 rpm and kept warm for 1 h. The temperature was then raised to 35°C and stirred for 3 h. The triethylamine hydrochloride solid was removed by filtration. The filtrate was concentrated under reduced pressure at 45°C and -0.09 MPa in a rotary evaporator to remove most of the tetrahydrofuran. The concentrate was poured into an excess of cold petroleum ether, the solid was precipitated and filtered, the solid was washed three times with cold petroleum ether, and dried at 50°C and vacuum degree -0.09MPa for 12h to obtain the self-made flame retardant. (2) Bromotetradecane, 1-vinylimidazole and anhydrous ethanol were mixed in a mass ratio of 2.5:1.3:10 and refluxed at 80°C and 300 rpm for 9 h. After cooling to room temperature, the reaction solution was poured into excess anhydrous diethyl ether and stirred vigorously at 1500 rpm, resulting in the precipitation of a white viscous solid. The supernatant was discarded, and the solid was washed three times with anhydrous diethyl ether and then dried at 40°C and a vacuum of -0.09 MPa for 24 h to obtain the quaternized intermediate. (3) Sodium dodecylbenzenesulfonate and deionized water were mixed at a mass ratio of 0.05:10 and stirred at 800 rpm for 3 h at 60 °C to obtain an aqueous emulsion; methyl methacrylate, butyl acrylate and divinylbenzene were mixed at a mass ratio of 7:2:1:10 and stirred at 200 rpm for 1 h at room temperature, and added to the same volume of aqueous emulsion, and stirred at 500 rpm for 30 min for pre-emulsification to obtain a pre-emulsion; 0.5 times the mass of sodium dodecylbenzenesulfonate was added to a supersulfurized solution. Ammonium persulfate was mixed with 10 times the amount of deionized water and added dropwise at 2 mL / min to the milky white pre-emulsion prepared above. The mixture was heated to 70 °C and stirred at 300 rpm for 6 h. A 10 wt% sodium chloride aqueous solution was added to break the emulsion. The mixture was stirred at 65 °C for 30 min. The mixture was filtered and washed three times with 50 °C deionized water and then once with room temperature deionized water. The mixture was then dried at 50 °C under a vacuum of -0.09 MPa for 6 h to obtain polymer particles with a particle size of 400 nm. (4) The polymer particles, quaternization intermediate, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 5.5:1.5:0.1:10 and stirred and refluxed at 105℃ and 500rpm for 6h. The mixture was filtered and the filter cake was washed twice with toluene to remove unreacted quaternary ammonium salt and catalyst. The mixture was then washed once with anhydrous ethanol to remove residual toluene. The mixture was filtered until no liquid dripped from the filter cake and dried at 90℃ and vacuum degree -0.09MPa for 12h to obtain the self-made antistatic particles. (5) Mix recycled PET chips with an intrinsic viscosity of 0.70 dL / g, glycidyl methacrylate and stannous octoate in a mass ratio of 100:5:0.3, put them into a high-speed mixer, adjust the mixing temperature to 120℃, the speed to 2000 rpm, mix for 30 min to make the raw materials uniformly mixed, and feed them into a twin-screw extruder. Set the temperature of each section of the extruder as follows: feed section 250℃, melt section 260℃, die head section 255℃, screw speed 180 rpm, connect the extruder outlet to a pelletizer, and extrude and pelletize to obtain modified PET with a particle size of 3 mm. (6) Modified PET, self-made flame retardant, self-made antistatic particles, and dicumyl peroxide are mixed in a mass ratio of 85:7:6:0.5 and placed in a high-speed mixer. The mixing temperature is adjusted to 120℃ and the rotation speed is 2000rpm. The mixture is mixed for 30min to ensure uniform dispersion of the raw materials and obtain a blend. The blend is then melt-spun through a spinneret with a 0.3mm orifice and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, and spinneret temperature 280℃. The spinning machine is turned on and preheated for 30min to ensure complete melting of the blend. The melt pressure is adjusted to 1. At 5 MPa, the spinneret assembly is turned on, and the spinneret rate is controlled. At the same time, the cooling air is turned on at a temperature of 25℃ and a speed of 0.8 m / s to cool and set the molten filament after spinning. The cooled and set fiber is then sent to the stretching device, where the stretching temperature is set to 85℃ and the stretching ratio is 3.5 times to perform stretching treatment and improve the mechanical properties of the fiber. The stretched fiber is then sent to the setting device, where the setting temperature is set to 120℃ and the setting time is 5 seconds. Then it is sent to the winding device, where the winding speed is adjusted to 2800 m / min to perform winding, resulting in a multifunctional three-porous recycled polyester fiber with a monofilament diameter of 12 μm and a porosity of 20%.

[0024] Example 4; (1) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-naphthoquinone and tetrahydrofuran were mixed in a mass ratio of 2.8:1.8:20. The mixture was stirred at 58°C and 300 rpm for 5.5 h under a nitrogen atmosphere. After naturally cooling to 5°C, 0.88 times the mass of 1,4-naphthoquinone acryloyl chloride and 1.15 times the mass of 1,4-naphthoquinone triethylamine were slowly added dropwise at a rate of 1 mL / min. The mixture was stirred at 200 rpm and kept warm for 1 h. The temperature was then raised to 38°C and stirred for 3.8 h. The triethylamine hydrochloride solid was removed by filtration. The filtrate was concentrated under reduced pressure at 48°C and -0.09 MPa on a rotary evaporator to remove most of the tetrahydrofuran. The concentrate was poured into an excess of cold petroleum ether, the solid was precipitated and filtered, the solid was washed three times with cold petroleum ether, and dried at 50°C and vacuum degree -0.09MPa for 12h to obtain the self-made flame retardant. (2) Bromotetradecane, 1-vinylimidazole and anhydrous ethanol were mixed in a mass ratio of 2.8:1.4:10 and refluxed at 85°C and 300 rpm for 9.5 h. After cooling to room temperature, the reaction solution was poured into excess anhydrous diethyl ether and stirred vigorously at 1500 rpm, resulting in the precipitation of a white viscous solid. The supernatant was discarded, and the solid was washed three times with anhydrous diethyl ether and then dried at 40°C and a vacuum of -0.09 MPa for 24 h to obtain the quaternized intermediate. (3) Sodium dodecylbenzenesulfonate and deionized water were mixed at a mass ratio of 0.05:10 and stirred at 800 rpm for 3.5 h at 60 °C to obtain an aqueous emulsion; methyl methacrylate, butyl acrylate and divinylbenzene were mixed at a mass ratio of 7.5:2.5:1:10 and stirred at 200 rpm for 1 h at room temperature, and added to the same volume of aqueous emulsion, and stirred at 500 rpm for 30 min for pre-emulsification to obtain a pre-emulsion; 0.55 times the mass of sodium dodecylbenzenesulfonate was added. Ammonium persulfate was mixed with 10 times its volume of deionized water and added dropwise at 2 mL / min to the milky white pre-emulsion prepared above. The mixture was heated to 75 °C and stirred at 300 rpm for 6.5 h. 10 wt% sodium chloride aqueous solution was added to break the emulsion. The mixture was stirred at 68 °C for 30 min. The mixture was filtered and washed three times with 50 °C deionized water and once with room temperature deionized water. The mixture was then dried at 50 °C and vacuum degree -0.09 MPa for 6 h to obtain polymer particles with a particle size of 450 nm. (4) The polymer particles, quaternization intermediate, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 5.8:1.8:0.1:10 and stirred and refluxed at 108℃ and 500rpm for 6.5h. The mixture was filtered and the filter cake was washed twice with toluene to remove unreacted quaternary ammonium salt and catalyst. The mixture was then washed once with anhydrous ethanol to remove residual toluene. The mixture was filtered until no liquid dripped from the filter cake and dried at 90℃ and vacuum degree -0.09MPa for 12h to obtain the self-made antistatic particles. (5) Mix recycled PET chips with an intrinsic viscosity of 0.70 dL / g, glycidyl methacrylate and stannous octoate in a mass ratio of 100:5:0.3, put them into a high-speed mixer, adjust the mixing temperature to 120℃, the speed to 2000 rpm, mix for 30 min to make the raw materials uniformly mixed, and feed them into a twin-screw extruder. Set the temperature of each section of the extruder as follows: feed section 250℃, melt section 260℃, die head section 255℃, screw speed 180 rpm, connect the extruder outlet to a pelletizer, and extrude and pelletize to obtain modified PET with a particle size of 3 mm. (6) Modified PET, self-made flame retardant, self-made antistatic particles, and dicumyl peroxide are mixed in a mass ratio of 88:9:7:0.5 and placed in a high-speed mixer. The mixing temperature is adjusted to 120℃ and the rotation speed is 2000rpm. The mixture is mixed for 30min to ensure uniform dispersion of the raw materials and obtain a blend. The blend is then melt-spun through a spinneret with a 0.3mm orifice and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, and spinneret temperature 280℃. The spinning machine is turned on and preheated for 30min to ensure complete melting of the blend. The melt pressure is adjusted to 1. At 5 MPa, the spinneret assembly is turned on, and the spinneret rate is controlled. At the same time, the cooling air is turned on at a temperature of 25℃ and a speed of 0.8 m / s to cool and set the molten filament after spinning. The cooled and set fiber is then sent to the stretching device, where the stretching temperature is set to 85℃ and the stretching ratio is 3.5 times to perform stretching treatment and improve the mechanical properties of the fiber. The stretched fiber is then sent to the setting device, where the setting temperature is set to 120℃ and the setting time is 5 seconds. Then it is sent to the winding device, where the winding speed is adjusted to 2800 m / min to perform winding, resulting in a multifunctional three-porous recycled polyester fiber with a monofilament diameter of 12 μm and a porosity of 20%.

[0025] Example 5; (1) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-naphthoquinone and tetrahydrofuran were mixed in a mass ratio of 3:2:20. Under a nitrogen atmosphere, the mixture was stirred at 60°C and 300 rpm for 6 h. After naturally cooling to 5°C, 0.9 times the mass of 1,4-naphthoquinone acryloyl chloride and 1.2 times the mass of 1,4-naphthoquinone triethylamine were slowly added dropwise at a rate of 1 mL / min. The mixture was stirred at 200 rpm and kept warm for 1 h. Then, the temperature was raised to 40°C and stirred for 4 h. The triethylamine hydrochloride solid was removed by filtration. The filtrate was concentrated under reduced pressure at 50°C and -0.09 MPa on a rotary evaporator to remove most of the tetrahydrofuran. The concentrate was poured into excess cold petroleum ether, and the solid precipitated and filtered. The solid was washed three times with cold petroleum ether and dried at 50°C and -0.09 MPa for 12 h to obtain the self-made flame retardant. (2) Bromotetradecane, 1-vinylimidazole and anhydrous ethanol were mixed in a mass ratio of 3:1.5:10 and refluxed at 90°C and 300 rpm for 10 h. After cooling to room temperature, the reaction solution was poured into excess anhydrous diethyl ether and stirred vigorously at 1500 rpm, resulting in the precipitation of a white viscous solid. The supernatant was discarded, and the solid was washed three times with anhydrous diethyl ether and then dried at 40°C and a vacuum of -0.09 MPa for 24 h to obtain the quaternized intermediate. (3) Sodium dodecylbenzenesulfonate and deionized water were mixed at a mass ratio of 0.05:10 and stirred at 800 rpm for 4 h at 60 °C to obtain an aqueous emulsion; methyl methacrylate, butyl acrylate and divinylbenzene were mixed at a mass ratio of 8:3:1:10 and stirred at 200 rpm for 1 h at room temperature, and added to the same volume of aqueous emulsion, and stirred at 500 rpm for 30 min for pre-emulsification to obtain a pre-emulsion; 0.6 times the mass of sodium dodecylbenzenesulfonate was added to a supersulfurized solution. Ammonium persulfate was mixed with 10 times the amount of deionized water and added dropwise at 2 mL / min to the milky white pre-emulsion prepared above. The mixture was heated to 80 °C and stirred at 300 rpm for 7 h. A 10 wt% sodium chloride aqueous solution was added to break the emulsion. The mixture was stirred at 70 °C for 30 min. The mixture was filtered and washed three times with 50 °C deionized water and then once with room temperature deionized water. The mixture was then dried at 50 °C under a vacuum of -0.09 MPa for 6 h to obtain polymer particles with a particle size of 500 nm. (4) The polymer particles, quaternization intermediate, p-toluenesulfonic acid and toluene were mixed in a mass ratio of 6:2:0.1:10 and stirred and refluxed at 110°C and 500 rpm for 7 h. The mixture was filtered and the filter cake was washed twice with toluene to remove unreacted quaternary ammonium salt and catalyst. The mixture was then washed once with anhydrous ethanol to remove residual toluene. The mixture was filtered until no liquid dripped from the filter cake and dried at 90°C and vacuum degree -0.09 MPa for 12 h to obtain the self-made antistatic particles. (5) Mix recycled PET chips with an intrinsic viscosity of 0.70 dL / g, glycidyl methacrylate and stannous octoate in a mass ratio of 100:5:0.3, put them into a high-speed mixer, adjust the mixing temperature to 120℃, the speed to 2000 rpm, mix for 30 min to make the raw materials uniformly mixed, and feed them into a twin-screw extruder. Set the temperature of each section of the extruder as follows: feed section 250℃, melt section 260℃, die head section 255℃, screw speed 180 rpm, connect the extruder outlet to a pelletizer, and extrude and pelletize to obtain modified PET with a particle size of 3 mm. (6) Modified PET, self-made flame retardant, self-made antistatic particles, and dicumyl peroxide are mixed in a mass ratio of 90:10:8:0.5 and placed in a high-speed mixer. The mixing temperature is adjusted to 120℃ and the rotation speed is 2000rpm. The mixture is mixed for 30min to ensure uniform dispersion of the raw materials and obtain a blend. The blend is then melt-spun through a spinneret with a 0.3mm orifice and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, and spinneret temperature 280℃. The spinning machine is turned on and preheated for 30min to ensure complete melting of the blend. The melt pressure is adjusted to... At 15 MPa, the spinneret assembly is turned on, and the spinneret rate is controlled. At the same time, the cooling air is turned on at a temperature of 25℃ and a speed of 0.8 m / s to cool and set the molten filament after spinning. The cooled and set fiber is then sent to the stretching device, where the stretching temperature is set to 85℃ and the stretching ratio is 3.5 times to perform stretching treatment and improve the mechanical properties of the fiber. The stretched fiber is then sent to the setting device, where the setting temperature is set to 120℃ and the setting time is 5 seconds. Then it is sent to the winding device, where the winding speed is adjusted to 2800 m / min to perform winding, resulting in a multifunctional three-porous recycled polyester fiber with a monofilament diameter of 12 μm and a porosity of 20%.

[0026] Comparative Example 1 The difference between Comparative Example 1 and Example 3 is that step (1) is omitted, and step (6) is changed to: Modified PET, self-made antistatic particles and dicumyl peroxide are mixed in a mass ratio of 85:6:0.5, placed in a high-speed mixer, the mixing temperature is adjusted to 120℃, the rotation speed is 2000rpm, and the mixture is mixed for 30min to make the raw materials uniformly dispersed to obtain a blended raw material. The blended raw material is melt-spun through a spinneret with a 0.3mm aperture and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, spinneret temperature 280℃. The spinning machine is turned on and preheated for 30min to make the blended raw material completely melted. The melt temperature is adjusted. The body pressure is brought up to 15 MPa, the spinneret assembly is turned on, the spinneret rate is controlled, and the cooling air is turned on at a temperature of 25°C and a speed of 0.8 m / s to cool and set the molten filament after spinning. The cooled and set fiber is then sent to a stretching device, where the stretching temperature is set to 85°C and the stretching ratio is 3.5 times to perform stretching treatment and improve the mechanical properties of the fiber. The stretched fiber is then sent to a setting device, where the setting temperature is set to 120°C and the setting time is 5 seconds. Then it is sent to a winding device, where the winding speed is adjusted to 2800 m / min to perform winding, resulting in a recycled polyester multifunctional triporous fiber with a monofilament diameter of 12 μm and a porosity of 20%. The remaining steps are the same as in Example 3.

[0027] Comparative Example 2 The difference between Comparative Example 2 and Example 3 is that step (2) is omitted, and step (4) is changed to: mixing polymer particles, p-toluenesulfonic acid and toluene in a mass ratio of 5.5:1.5:0.1:10, stirring and refluxing at 105°C and 500 rpm for 6 h, filtering and washing the filter cake twice with toluene to remove unreacted quaternary ammonium salt and catalyst, washing once with anhydrous ethanol to remove residual toluene, filtering until no liquid drips from the filter cake, and drying at 90°C and vacuum degree -0.09 MPa for 12 h to obtain self-made antistatic particles. The remaining steps are the same as in Example 3.

[0028] Comparative Example 3 The difference between Comparative Example 3 and Example 3 is that steps (3) and (4) are omitted, and step (6) is changed to: Modified PET, self-made flame retardant, quaternized intermediate and dicumyl peroxide are mixed in a mass ratio of 85:7:6:0.5 and placed in a high-speed mixer. The mixing temperature is adjusted to 120°C and the rotation speed is 2000 rpm. The mixture is mixed for 30 min to make the raw materials uniformly dispersed and obtain a blended raw material. The blended raw material is melt-spun through a spinneret with a 0.3 mm orifice and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260°C, screw zone 2 270°C, screw zone 3 275°C, spinneret temperature 280°C. The spinning machine is turned on and preheated for 30 min to make the blended raw material completely melt. Melt the filaments, adjust the melt pressure to 15 MPa, turn on the spinneret assembly, control the spinneret rate, and simultaneously turn on the cooling air at a temperature of 25°C and a speed of 0.8 m / s to cool and set the filaments. Then, send the cooled and set fibers into a stretching device, set the stretching temperature to 85°C and the stretching ratio to 3.5 times, and perform stretching treatment to improve the mechanical properties of the fibers. The stretched fibers are then sent into a setting device, set the setting temperature to 120°C and the setting time to 5 seconds, and then sent into a winding device. The winding speed is adjusted to 2800 m / min for winding to obtain a recycled polyester multifunctional triporous fiber with a monofilament diameter of 12 μm and a porosity of 20%. The remaining steps are the same as in Example 3.

[0029] Comparative Example 4 The difference between Comparative Example 4 and Example 3 is that steps (2), (3), and (4) are omitted, and step (6) is changed to: Modified PET, self-made flame retardant, and dicumyl peroxide are mixed in a mass ratio of 85:7:0.5, placed in a high-speed mixer, and the mixing temperature is adjusted to 120℃, the rotation speed to 2000 rpm, and mixed for 30 minutes to ensure uniform dispersion of the raw materials, resulting in a blend. This blend is then melt-spun through a spinneret with a 0.3mm orifice and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, and spinneret temperature 280℃. The spinning machine is turned on and preheated for 30 minutes to ensure complete melting of the blend. Reduce the melt pressure to 15 MPa, turn on the spinneret assembly, control the spinneret rate, and simultaneously turn on the cooling air at a temperature of 25°C and a speed of 0.8 m / s to cool and set the spun melt filaments. Then, send the cooled and set fibers into a stretching device, set the stretching temperature to 85°C and the stretching ratio to 3.5 times, and perform stretching treatment to improve the mechanical properties of the fibers. After stretching, send the fibers into a setting device, set the setting temperature to 120°C and the setting time to 5 seconds, and then send them into a winding device. Adjust the winding speed to 2800 m / min and perform winding to obtain a recycled polyester multifunctional triporous fiber with a monofilament diameter of 12 μm and a porosity of 20%. The remaining steps are the same as in Example 3.

[0030] Comparative Example 5 The difference between Comparative Example 5 and Example 3 is that step (5) is omitted, and step (6) is changed to: Recycled PET chips with an intrinsic viscosity of 0.70 dL / g, self-made flame retardant, self-made antistatic particles, and dicumyl peroxide are mixed in a mass ratio of 85:7:6:0.5, placed in a high-speed mixer, and the mixing temperature is adjusted to 120℃, the rotation speed to 2000 rpm, and mixed for 30 minutes to ensure uniform dispersion of the raw materials, resulting in a blend. This blend is then melt-spun through a spinneret with a 0.3mm orifice and a three-hole triangular arrangement. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, and spinneret temperature 280℃. The spinning machine is then turned on and preheated for 30 minutes. The blended raw materials were completely melted, and the melt pressure was adjusted to 15 MPa. The spinneret was turned on, and the spinning rate was controlled. At the same time, the cooling air was turned on at a temperature of 25°C and a speed of 0.8 m / s to cool and set the molten filaments after spinning. The cooled and set fibers were then sent to a stretching device, where the stretching temperature was set to 85°C and the stretching ratio was 3.5 times to perform stretching treatment and improve the mechanical properties of the fibers. The stretched fibers were then sent to a setting device, where the setting temperature was set to 120°C and the setting time was 5 seconds. Then, the fibers were sent to a winding device, where the winding speed was adjusted to 2800 m / min to perform winding, resulting in a recycled polyester multifunctional triporous fiber with a monofilament diameter of 12 μm and a porosity of 20%. The remaining steps were the same as in Example 3.

[0031] Comparative Example 6 The difference between Comparative Example 6 and Example 3 lies in step (6). Step (6) is changed to: mixing modified PET, self-made flame retardant, self-made antistatic particles and dicumyl peroxide in a mass ratio of 85:7:6:0.5, placing them in a high-speed mixer, adjusting the mixing temperature to 120℃, the rotation speed to 2000rpm, mixing for 30min to ensure uniform dispersion of the raw materials, obtaining a blended raw material, and performing melt spinning. The parameters are set as follows: screw zone 1 260℃, screw zone 2 270℃, screw zone 3 275℃, spinneret temperature 280℃, turning on the spinning machine, preheating for 30min to ensure complete melting of the blended raw material, and adjusting the melt... The pressure was increased to 15 MPa, the spinneret assembly was turned on, the spinneret rate was controlled, and the cooling air was turned on at a temperature of 25°C and a speed of 0.8 m / s to cool and set the molten filament after spinning. The cooled and set fiber was then sent to a stretching device, where the stretching temperature was set to 85°C and the stretching ratio was 3.5 times to perform stretching treatment and improve the mechanical properties of the fiber. The stretched fiber was then sent to a setting device, where the setting temperature was set to 120°C and the setting time was 5 seconds. Then it was sent to a winding device, where the winding speed was adjusted to 2800 m / min to perform winding, resulting in a recycled polyester multifunctional fiber with a single filament diameter of 12 μm. The remaining steps were the same as in Example 3.

[0032] Example of effect Table 1 below presents the performance analysis results of the recycled polyester multifunctional triporous fibers using Examples 1 to 5 and Comparative Examples 1 to 6 of the present invention.

[0033] Table 1

[0034] A comparison of the experimental data on the tensile strength of the examples and comparative examples reveals that the present invention first uses DOPO and 1,4-naphthoquinone via nucleophilic addition, followed by esterification with acryloyl chloride to obtain a self-made flame retardant containing double bonds; then, after quaternization of bromoalkyl and vinylimidazole, it is grafted onto the surface of a polymer obtained by emulsion polymerization of acrylate monomers to obtain self-made antistatic particles containing double bonds; the above two self-made materials are blended with recycled PET chips grafted with monomers containing double bonds through esterification and an initiator, and then melt-spun through a "T-shaped" spinneret assembly to obtain recycled polyester multifunctional triporous fibers; the three-dimensional cross-linked polymer network improves the tensile strength of the fibers, while also avoiding the physical separation of functional components from the matrix. Furthermore, the dispersion and toughening effect of the self-made antistatic particles, the rigid group reinforcement of the self-made flame retardant, and the increased specific surface area of ​​the triporous fibers result in a faster melt cooling rate during melt spinning. More uniform and more complete crystalline regions are formed, and the three factors work synergistically to endow the fiber with excellent mechanical properties. A comparison of the oxygen index experimental data of the examples and comparative examples reveals that the self-made flame retardant in this invention can form a dense and continuous char layer during high-temperature combustion, effectively blocking heat transfer to the interior. Furthermore, the conjugated naphthalene ring can promote the aromatization and graphitization of the char layer, improving its thermal stability and density, further enhancing the flame retardant effect. Simultaneously, the self-made antistatic particles decompose at high temperatures to generate hydrogen halide gas, which can capture active free radicals during combustion and inhibit chain combustion reactions in the gas phase. The synergistic effect of these two factors endows the fiber with excellent flame retardant properties. A comparison of the surface resistivity experimental data of the examples and comparative examples reveals that the polar groups in the self-made flame retardant in this invention can form ion pairs with quaternary ammonium salt groups, increasing the concentration of free ions and improving ion conductivity, thus giving the fiber good antistatic properties.

[0035] 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 implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A multifunctional triporous fiber made from recycled polyester, characterized in that, Includes the following steps: (1) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 1,4-naphthoquinone and tetrahydrofuran were mixed in a mass ratio of 2~3:1~2:

20. The mixture was stirred and reacted at 50~60℃ for 4~6h under a nitrogen atmosphere. After naturally cooling to 5℃, 0.8~0.9 times the mass of 1,4-naphthoquinone acryloyl chloride and 1~1.2 times the mass of 1,4-naphthoquinone acid binder were slowly added dropwise. The mixture was stirred and kept warm at 200rpm for 1h. The temperature was then raised to 30~40℃ and stirred and reacted for 2~4h. The mixture was filtered and concentrated under reduced pressure. After vacuum filtration, the mixture was washed three times with petroleum ether and dried under vacuum at 50℃ for 12h to obtain the self-made flame retardant. (2) Bromoalkyl, 1-vinylimidazolium and anhydrous ethanol are mixed in a mass ratio of 2~3:1~1.5:10 and stirred and refluxed at 70~90℃ for 8~10h. After filtration and washing, the mixture is dried under vacuum at 40℃ for 24h to obtain a quaternized intermediate. Then, polymer particles obtained by emulsion polymerization of acrylate monomers, the quaternized intermediate, the catalyst and toluene are mixed in a mass ratio of 5~6:1~2:0.1:10 and stirred and refluxed at 100~110℃ for 5~7h. After filtration and washing, the mixture is dried at 90℃ and vacuum degree -0.09MPa for 12h to obtain self-made antistatic particles. (3) Modified PET grafted with glycidyl methacrylate, self-made flame retardant, self-made antistatic particles and initiator are mixed at a mass ratio of 80~90:5~10:4~8:0.5, mixed at high speed for 30 minutes, melt spun through a spinneret with three holes arranged in a triangular pattern, and then stretched, shaped and wound to obtain recycled polyester multifunctional three-hole fiber.

2. The multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The slow dripping rate in step (1) is 1 mL / min.

3. The multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The acid-binding agent in step (1) is triethylamine.

4. The multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The bromohydrocarbon mentioned in step (2) is bromotetradecane.

5. The multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The acrylate monomers mentioned in step (2) are methyl methacrylate and butyl acrylate.

6. The multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The polymer particles in step (2) have a particle size of 300~500nm.

7. The multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The catalyst in step (2) is p-toluenesulfonic acid.

8. The multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The PET mentioned in step (3) is: recycled PET chips with an intrinsic viscosity of 0.70 dL / g.

9. The multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The initiator in step (3) is dicumyl peroxide.

10. A multifunctional triporous fiber of recycled polyester according to claim 1, characterized in that, The recycled polyester multifunctional triporous fiber mentioned in step (3) has a single filament diameter of 12μm and a porosity of 20%.

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