A production process for cationic trilobal profiled recycled polyester fiber

Abstract

This invention discloses a production process for cationic trilobal profiled recycled polyester fiber, belonging to the field of spinning technology, including the following steps: (1) feeding recycled cationic polyester chips into a crystallization drying system for crystallization drying treatment; (2) melting the dried recycled cationic polyester chips and a modifier, or melting the dried recycled cationic polyester chips to obtain a spinning melt, then conveying the melt to a spinning box, metering it with a metering pump, and then pressing it into a spinning assembly to extrude and form a nascent filament bundle; (3) subjecting the nascent filament bundle to post-heating, airless zone, ring blowing cooling, bundling and oiling treatment, and then to pre-networking, stretching and shaping, and winding to obtain cationic trilobal profiled recycled polyester fiber. The cationic trilobal profiled recycled polyester fiber of this invention can increase the dyeing rate and quick-drying performance of polyester fiber, and the introduction of a core-shell structure with ammonium polyphosphate as the core and chitosan as the shell can increase the flame retardant performance of the fiber.

Description

Technical Field

[0001] This invention relates to the field of spinning technology, and more specifically, to a production process for cationic trilobal profiled recycled polyester fibers. Background Technology

[0002] Cationic trilobal polyester fibers can create a visually three-dimensional design in fabrics through a two-tone effect, and are commonly used in high-end sportswear, fashion apparel, and home furnishings. Their unique fiber cross-sectional shape enhances the fabric's anti-pilling properties, breathability, and cohesion, while also improving the fabric's feel and appearance. Cationic trilobal polyester fibers are also used in the production of two-tone effect fabrics and blended fabrics. They solve the dyeing difficulties associated with ordinary polyester fibers and impart antistatic and quick-drying properties to the fabric.

[0003] Although cationic trilobal shaped polyester fibers can improve the dyeing rate of polyester fibers, their flame retardant properties are significantly insufficient. Core-shell structured materials with flame-retardant properties can be introduced to enhance this function. However, the interfacial compatibility between flame retardants and polyester fibers is poor, which in turn affects the mechanical properties of the fibers. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a production process for cationic trilobal profiled recycled polyester fiber.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A process for producing cationic trilobal profiled recycled polyester fiber includes the following steps:

[0007] (1) The recycled cationic polyester chips are put into the crystallization drying system for crystallization drying treatment;

[0008] (2) The dried recycled cationic polyester chips and modifier are fed to the screw extruder for melting, or the dried recycled cationic polyester chips are fed to the screw extruder for melting to obtain the spinning melt. The melt is then fed to the spinning box, metered by the metering pump, and then pressed into the spinning assembly to form a non-circular cross section of the nascent filament bundle.

[0009] (3) The nascent filament bundles with irregular cross sections are heated, cooled in a windless zone, cooled by ring blowing, and bundled and oiled. Then, they are pre-networked, drawn and shaped, and wound to obtain cationic trilobal irregular cross section recycled polyester fibers.

[0010] Furthermore, in step (1), the crystallization temperature is 150-160℃, the drying temperature is 150-170℃, and the drying air pressure is 0.05-0.15MPa.

[0011] Furthermore, in step (2), the modifier is ammonium polyphosphate powder coated with chitosan and di(ethylene glycol butyl ether) phthalate auxiliary agent.

[0012] Furthermore, in step (2), the heating temperatures of each melting zone are 270-280℃ for zone 1, 280-290℃ for zone 2, 280-290℃ for zone 3, 280-290℃ for zone 4, and 280-290℃ for zone 5.

[0013] Furthermore, in step (2), the temperature of the spinning box is 280-290℃, and the pump supply of the metering pump is 50-60g / min.

[0014] Furthermore, in step (3), the post-heating temperature of the irregular cross-section nascent filament bundle is 280-300℃, the height of the windless zone is 40-60mm, and the air pressure of the ring-blowing cooling is 40-50Pa.

[0015] Furthermore, in step (3), during the oiling process of the irregular cross-section nascent filament bundle, the distance between the oil nozzle and the spinneret is 800-1200mm, and the distance between the bundle guide hook and the oil nozzle is 150-250mm.

[0016] Furthermore, in step (3), during the oiling process of the irregular cross-section nascent filament bundle, the oil concentration ratio is 11% by mass, and the pressure of the pre-network is 0.05-0.15 MPa.

[0017] Furthermore, in step (3), during the stretching and shaping process, the rotation speed of the first stretching roller is 2000-3000 m / min, and the rotation speed of the second stretching roller is 2400-2500 m / min.

[0018] Furthermore, in step (3), during the winding process, the winding tension is 15-20cN and the winding speed is 2400-2500m / min.

[0019] In summary, the present invention has the following beneficial effects:

[0020] The cationic trilobal profiled recycled polyester fiber of the present invention can increase the dyeing rate and quick-drying performance of polyester fiber. The introduction of a core-shell structure with rigid ammonium polyphosphate as the core and flexible chitosan as the shell can increase the flame retardant performance of the fiber. While maintaining high dyeing rate and quick-drying performance, the mechanical properties of the fiber are also increased. Attached Figure Description

[0021] Figure 1 The cross-sectional shape of the fiber under a microscope;

[0022] Figure 2 This is a schematic diagram of the spinneret orifice.

[0023] In the figure: discharge hole 31, arc 311, end 312. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] A process for producing cationic trilobal profiled recycled polyester fiber includes the following steps:

[0026] (1) The recycled cationic polyester chips are put into the crystallization drying system for crystallization drying treatment. The crystallization temperature is 150-160℃, the drying temperature is 150-170℃, and the drying air pressure is 0.05-0.15MPa.

[0027] (2) The dried recycled cationic polyester chips and modifier are fed to a screw extruder for melting, or the dried recycled cationic polyester chips are fed to a screw extruder for melting. The modifier is ammonium polyphosphate powder coated with chitosan and di(ethylene glycol butyl ether) phthalate auxiliaries to obtain spinning melt. The melt is then fed to the spinning box, metered by a metering pump, and pressed into the spinning assembly to form a shaped cross section of nascent filament bundle. The heating temperatures of each melting zone are 270-280℃ for zone 1, 280-290℃ for zone 2, 280-290℃ for zone 3, 280-290℃ for zone 4, and 280-290℃ for zone 5. The temperature of the spinning box is 280-290℃, and the pump supply of the metering pump is 50-60g / min.

[0028] (3) The nascent filaments with irregular cross-sections undergo post-heating, airless zone, ring-blown cooling, and bundling and oiling treatments, followed by pre-networking, stretching and setting, and winding to obtain cationic trilobal irregular cross-section recycled polyester fibers. The post-heating temperature of the nascent filaments with irregular cross-sections is 280-300℃, the height of the airless zone is 40-60mm, and the air pressure of the ring-blown cooling is 40-50Pa. During the bundling and oiling treatment of the nascent filaments with irregular cross-sections, the distance between the oil nozzle and the spinneret is 800-1200mm, and the bundling guide hook is used. The distance from the oil nozzle is 150-250mm. During the oiling process of the irregular cross-section nascent filament bundle, the oil concentration ratio is 11% by mass, the pre-network pressure is 0.05-0.15MPa, the speed of the first drafting roller is 2000-3000m / min, the speed of the second drafting roller is 2400-2500m / min, and the winding tension is 15-20cN and the winding speed is 2400-2500m / min.

[0029] Example 1

[0030] (1) The recycled cationic polyester chips were put into the crystallization drying system for crystallization drying treatment. The crystallization temperature was 155℃, the drying temperature was 160℃, and the drying air pressure was 0.1MPa.

[0031] (2) The dried recycled cationic polyester chips are fed to a screw extruder for melting (the screw extruder has a diameter of 90 mm, an aspect ratio of 25, and the temperatures of the five heating zones of the screw extruder are 278℃, 282℃, 284℃, 286℃, and 288℃ respectively; the extrusion pressure is 11.5 MPa, and the filtration pressure is 9.2 MPa) to obtain a spinning melt. The melt is then fed to the spinning box, where the temperature is 286℃ (the spinneret of the spinning assembly has a trilobal cross-section, such as...). Figure 2 As shown), the metering pump has a pump supply of 57g / min. After being metered by the metering pump, the melt is pressed into the spinning assembly (the assembly uses 120g of 100-mesh metal sand and a 40μm filter screen with nine layers of 800-mesh mesh) and extruded to form a primary filament bundle with an irregular cross-section.

[0032] The spinneret includes a discharge orifice 31, which has a Y-shaped cross-section and is a centrally symmetrical trilobal type. The three ends 312 of the discharge orifice 31 are all semi-circular, and adjacent ends 312 are connected by an arc 311. Figure 2 For reference, the vertical distance L1 = 0.2mm between the center line connecting the ends 312 of the two lower discharge holes 31 and the center of the end 312 of the upper discharge hole 31, the radius R1 of the arc 311 is 0.22mm, and the radius R2 of the end 312 is 0.03mm.

[0033] (3) The nascent filament bundles with irregular cross-sections undergo post-heating, airless zone, ring-blown cooling, and bundling and oiling treatments, followed by pre-networking, drafting and setting, and winding. The post-heating temperature is 295℃, the height of the airless zone is 54mm, and the air pressure of the ring-blown cooling is 45Pa. During the bundling and oiling process, the distance between the oil nozzle and the spinneret is 1000mm, the distance between the bundling guide hook and the oil nozzle is 200mm, the oil concentration ratio is 11% by mass, the pressure of the pre-networking is 0.08MPa, the rotation speed of the first drafting roller is 2440m / min, the rotation speed of the second drafting roller is 2450m / min, and the winding speed is 2428m / min with a winding tension of 18cN, resulting in cationic trilobal irregular cross-section recycled polyester fiber POY. Figure 1 The image shows the cross-sectional shape of the fiber under a microscope, revealing that all fiber cross-sections are triangular.

[0034] Example 2

[0035] (1) Take 10g of ammonium polyphosphate (APP, Shanghai Yuanye Biotechnology Co., Ltd., S67475-500g), add 200mL of deionized water, and stir for 30min at room temperature to obtain an ammonium polyphosphate suspension. Take 1g of chitosan (CS, degree of deacetylation >95%, viscosity 100~200MPa.s, Shandong Haiyihua Biotechnology Co., Ltd., 9012-76-4), add 100mL of acetic acid solution (acetic acid solution mass fraction is 1%), and stir for 30min to obtain a chitosan solution. Add the chitosan solution dropwise to the ammonium polyphosphate suspension, stir for 2h, wash with anhydrous ethanol, centrifuge at 3000rpm for 3min to obtain a precipitate, remove the supernatant, and dry at 80℃ for 24h to obtain chitosan-coated ammonium polyphosphate powder, denoted as APP@CS.

[0036] Phthalic anhydride (analytical grade, purchased from Shanghai Maclean Biochemical Technology Co., Ltd., catalog number: P816733-500g), diethylene glycol butyl ether (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., catalog number: B110647-100ml), aqueous solution toluene, and SO4 2- TiO2 catalyst was added to a reflux condenser reactor equipped with a water separator at a molar ratio of 2:6:2:0.08. The reaction solution was heated to boiling, and the reactor temperature and top temperature were recorded simultaneously. Water generated during the process was separated out as needed, while ensuring that the water-carrying agent was returned to the reactor for recycling. The reaction ended when no more water was produced from the reaction system. After the reaction, the mixture was filtered, and impurities (toluene and ethylene glycol ether) were removed under a vacuum of 0.09 MPa. A small amount of sodium hydroxide aqueous solution was added for neutralization to remove unreacted monoesters. After decolorization with activated carbon, filtration, and dehydration, di(ethylene glycol butyl ether) phthalate auxiliaries were obtained.

[0037] SO4 2- Preparation method of TiO2 catalyst: A quantitative amount of TiCl4 was dissolved in cyclohexane to prepare a 20% (w / w) solution. While stirring, a 28% (w / w) ammonia solution was slowly added dropwise to adjust the pH to 10, resulting in an amorphous Ti(OH)4 precipitate. The precipitate was allowed to stand for 24 hours and then washed repeatedly with anhydrous ethanol and distilled water until no chloride ions were found (tested with 0.1 mol / L AgNO3 solution). After drying at 100℃, the precipitate was ground and sieved through a 100-mesh sieve to obtain TiO2 powder. TiO2 powder was weighed and added to a 0.75 mol / L sulfuric acid solution at a ratio of 1 g:16 mL. The mixture was refluxed and stirred at 60℃ for 12 hours, filtered, and calcined at 450℃ for 4 hours to obtain SO42-. 2- / TiO2 catalyst.

[0038] The recycled cationic polyester chips were put into a crystallization and drying system for crystallization and drying treatment. The crystallization temperature was 155℃, the drying temperature was 160℃, and the drying air pressure was 0.1MPa.

[0039] (2) The dried recycled cationic polyester chips, APP@CS powder, and di(ethylene glycol butyl ether) phthalate additive were added to a mixer at a mass ratio of 100:3:5 and mixed evenly. The mixture was then fed to a screw extruder for melting (the screw extruder had a diameter of 90 mm, an aspect ratio of 25, and five heating zones with temperatures of 278℃, 282℃, 284℃, 286℃, and 288℃ respectively; the extrusion pressure was 11.5 MPa, and the post-filtration pressure was 9.2 MPa) to obtain a spinning melt. The melt was then fed to a spinning box at a temperature of 286℃ (the spinneret of the spinning assembly had a trilobal cross-section, such as...). Figure 2 As shown), the metering pump has a pump supply of 57g / min. After being metered by the metering pump, the melt is pressed into the spinning assembly (the assembly uses 120g of 100-mesh metal sand and a 40μm filter screen with nine layers of 800-mesh mesh) and extruded to form a primary filament bundle with an irregular cross-section.

[0040] (3) The nascent filament bundle with irregular cross-section undergoes post-heating, airless zone, ring air cooling, and bundle oiling treatment, followed by pre-networking, stretching and setting, and winding. The post-heating temperature is 295℃, the height of the airless zone is 54mm, and the air pressure of the ring air cooling is 45Pa. During the bundle oiling treatment, the distance between the oil nozzle and the spinneret is 1000mm, the distance between the bundle guide hook and the oil nozzle is 200mm, the oil concentration ratio is 11% by mass, the pressure of the pre-network is 0.08MPa, the rotation speed of the first stretching roller is 2440m / min, the rotation speed of the second stretching roller is 2450m / min, and the winding speed is 2428m / min with a winding tension of 18cN to obtain cationic trilobal irregular cross-section recycled polyester fiber POY.

[0041] Comparative Example 1

[0042] The cationic trilobal cross-section recycled polyester fiber POY was prepared according to Example 2, except that: in step (1), ammonium polyphosphate powder coated with chitosan was not prepared, and in step (2), solid ammonium polyphosphate, di(ethylene glycol butyl ether) phthalate auxiliaries and recycled polyester fiber chips were directly fed to a screw extruder for melt extrusion.

[0043] Comparative Example 2

[0044] The cationic trilobal cross-section recycled polyester fiber POY was prepared according to Example 2, except that: in step (1), the polyphosphate powder coated with chitosan and the di(ethylene glycol butyl ether) phthalate additive were not prepared, and the solid polyphosphate was directly mixed with the recycled polyester fiber chips and fed to the screw extruder for melt extrusion.

[0045] Comparative Example 3

[0046] The cationic trilobal cross-section recycled polyester fiber POY was prepared according to Example 2, except that: in step (1), di(ethylene glycol butyl ether) phthalate was not prepared, and in step (2), the chitosan-coated ammonium polyphosphate powder and recycled polyester fiber chips were directly fed to the screw extruder for melt extrusion.

[0047] Comparative Example 4

[0048] The cationic trilobal cross-section recycled polyester fiber POY was prepared according to Example 2, except that: in step (1), ammonium polyphosphate powder coated with chitosan was not prepared, and in step (2), di(ethylene glycol butyl ether) phthalate auxiliaries and recycled polyester fiber chips were directly fed to a screw extruder for melt extrusion.

[0049] The cationic trilobal shaped cross-section recycled polyester fiber POY prepared in Examples 1-2 and Comparative Examples 1-4 were subjected to physical property tests. The tests showed that the obtained cationic trilobal shaped cross-section recycled polyester fiber POY has advantages such as high breaking strength, high thermal stress, and stable strength. Table 1 shows the physical property data of cationic trilobal shaped cross-section recycled polyester fiber POY in Examples 1 and 2.

[0050] Table 1. Physical properties of cationic trilobal profiled recycled polyester fiber (POY)

[0051]

[0052] Linear density was tested according to GB14343-2008 "Test Method for Linear Density of Chemical Fiber Filaments"; breaking strength was tested according to GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments"; breaking elongation was tested according to GB / T14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments"; thermal stress was tested according to ISO 12834:2024 international standard "Textiles - Determination of Dynamic Thermal Stress of Pre-oriented Synthetic Fiber Filaments"; 60% elongation strength was tested according to GB / T14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments"; evenness (CV) was tested according to GB / T3292.1-2008 "Textiles - Test Method for Yarn Unevenness - Part 1: Capacitance Method"; oil content was tested according to GB / T 6504-2017 "Test Method for Oil Content of Chemical Fibers"; drying rate was tested according to GB / T The test shall be conducted in accordance with 21655.1-2023 "Evaluation of the moisture absorption and quick-drying properties of textiles - Part 1: Single combination test method".

[0053] The test results showed that the elongation at break of Comparative Examples 1 to 4 were 155%, 142%, 138%, and 146%, respectively; and the uniformity of the strips of Comparative Examples 1 to 4 were 0.79%, 0.81%, 0.85%, and 0.75%, respectively.

[0054] Phthalic anhydride and diethylene glycol butyl ether react under catalysis to yield di(ethylene glycol butyl ether) phthalate auxiliaries. The auxiliaries have carboxyl and ester groups on their side chains, which can adsorb onto the surface of core-shell structured particles to form a coating layer, effectively inhibiting flame retardant aggregation. Simultaneously, the phthalate ester structure in the auxiliaries is similar to the ester bond and benzene ring structure of polyester fibers, allowing it to insert between polyester fiber molecular chains and significantly improve the compatibility between chitosan and polyester fibers. The physical performance test results showed that Comparative Examples 2 and 3, which only added flame retardants without di(ethylene glycol butyl ether) phthalate, performed poorly, indicating that the compatibility between a single flame retardant and polyester fibers was not good. Compared with Examples 1 and 4, Example 2, which added di(ethylene glycol butyl ether) phthalate, showed significantly improved performance, proving that di(ethylene glycol butyl ether) phthalate can effectively enhance the interfacial compatibility between flame retardants and cationic trefoil cross-section recycled polyester fibers.

[0055] The finished cationic trilobal irregular cross-section recycled polyester fiber POY was prepared according to the methods of Examples 1-2 and Comparative Examples 1-4, and the dyeing rate was tested, as shown in Table 2.

[0056] Table 2 Dyeing Rate Test

[0057]

[0058] The dyeing rate was tested according to FZ / T 50020-2013 "Test Method for Dyeing Rate of Cationic Dyeable Modified Polyester".

[0059] The cationic trilobal cross-section recycled polyester fiber of this invention, after chemical modification, introduces anionic groups such as sulfonic acid groups into the recycled cationic polyester molecular chain. During the dyeing process, positively charged cationic dyes can form ionic bonds with these groups. Simultaneously, the trilobal cross-section design of the fiber effectively increases the specific surface area, further enhancing the adsorption effect on dyes, thus giving the fiber excellent dyeing uptake performance.

[0060] The finished cationic trilobal irregular cross-section recycled polyester fiber POY was prepared according to the methods of Examples 1-2 and Comparative Examples 1-4, and the oxygen index was tested, as shown in Table 3.

[0061] Table 3 Oxygen Index Test

[0062]

[0063] The oxygen index was tested on cationic trilobal profiled recycled polyester fiber according to FZ / T 50016-2023 "Test Method for Combustion Performance of Chemical Fibers - Oxygen Index Method".

[0064] The oxygen index test results of the cationic trilobal cross-section recycled polyester fiber POY of the present invention show that after adding ammonium polyphosphate flame retardant (Example 2, Comparative Examples 1-3), the flame retardant performance of the polyester fiber is increased to a certain extent. Example 2 reaches the highest value of 30.8%, indicating that the core-shell structure flame retardant prepared with ammonium polyphosphate as the core and chitosan as the shell can effectively enhance the flame retardant performance of cationic trilobal cross-section recycled polyester fiber.

[0065] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A production process for cationic trilobal profiled recycled polyester fiber, characterized in that, Includes the following steps: (1) The recycled cationic polyester chips are put into the crystallization drying system for crystallization drying treatment; (2) The dried recycled cationic polyester chips and modifier are fed to the screw extruder for melting, or the dried recycled cationic polyester chips are fed to the screw extruder for melting to obtain the spinning melt. The melt is then fed to the spinning box, metered by the metering pump, and then pressed into the spinning assembly to form a non-circular cross section of the nascent filament bundle. (3) The nascent filament bundles with irregular cross sections are heated, cooled in a windless zone, cooled by ring blowing, and bundled and oiled. Then, they are pre-networked, drawn and shaped, and wound to obtain cationic trilobal irregular cross section recycled polyester fibers.

2. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (1), the crystallization temperature is 150-160℃, the drying temperature is 150-170℃, and the drying air pressure is 0.05-0.15MPa.

3. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (2), the modifier is ammonium polyphosphate powder coated with chitosan and di(ethylene glycol butyl ether) phthalate auxiliary agent.

4. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (2), the heating temperatures of each melting zone are 270-280℃ for zone 1, 280-290℃ for zone 2, 280-290℃ for zone 3, 280-290℃ for zone 4, and 280-290℃ for zone 5.

5. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (2), the temperature of the spinning box is 280-290℃, and the pump supply of the metering pump is 50-60g / min.

6. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (3), the post-heating temperature of the irregular cross-section nascent filament bundle is 280-300℃, the height of the windless zone is 40-60mm, and the air pressure of the ring blowing cooling is 40-50Pa.

7. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (3), during the oiling process of the irregular cross-section nascent filament bundle, the distance between the oil nozzle and the spinneret is 800-1200mm, and the distance between the bundle guide hook and the oil nozzle is 150-250mm.

8. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (3), during the oiling process of the irregular cross-section nascent filament bundle, the oil concentration ratio is 11% by mass, and the pressure of the pre-network is 0.05-0.15 MPa.

9. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (3), during the stretching and setting process, the rotation speed of the first stretching roller is 2000-3000 m / min, and the rotation speed of the second stretching roller is 2400-2500 m / min.

10. The production process of cationic trilobal profiled recycled polyester fiber according to claim 1, characterized in that, In step (3), the winding tension is 15-20 cN and the winding speed is 2400-2500 m / min.

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