Preparation method of composite high-elastic polyamide FDY (Fully Drawn Yarn) filament

Abstract

The invention relates to a preparation method of a composite high-elastic polyamide FDY (Fully Drawn Yarn) filament, which comprises the following steps: step 1, respectively compressing, melting and homogenizing PA6 slices and PA56 slices through two screw extruders to obtain two melts; 2, enabling the two melts to respectively flow through a metering pump, a guide plate in a spinning assembly, metal sand and a distribution plate, and then compounding and extruding at a parallel spinneret plate to form a melt trickle; 3, cooling and curing the melt trickles through cross air blowing, bundling and oiling to obtain nascent fibers; and 4, preparing the nascent fiber into the composite high-elastic polyamide FDY filament through a drafting and winding integrated machine.

Description

Technical Field

[0001] The present invention relates to the technical field of polyamide filaments, and particularly to a preparation method of composite high-elastic polyamide FDY filaments. Background Art

[0002] With the rapid development of various industries, the performance requirements for polyamide fibers are increasing day by day. Especially in the field of high-performance textiles, it has become an urgent task to develop polyamide filaments with more excellent performance. Taking high-end sportswear as an example, consumers not only pursue the wearing comfort of clothing but also require good elastic recovery performance during exercise and still maintain shape and performance stability after multiple washes.

[0003] Currently, there are some related patented technologies. For example, Patent No. CN118422375 discloses an elastic polyamide fiber and its manufacturing method. This technology uses a polyamide elastic composite as the skin layer and a blend polyamide as the core layer to form an eccentric composite elastic polyamide fiber. By specific copolymer polyamide 6 / 66 molecular structure design and an off-chain hydrogen bond regulator ionic liquid to regulate the hydrogen bonds between polyamide molecular chains, but the preparation process of this technology is complex and difficult.

[0004] Patent No. CN109208113A discloses a polyamide 6 elastic fiber and its preparation method. This technology requires the preparation of modified polyamide chips to make the fiber have the characteristics of light weight, high strength, high elongation at break, low modulus, and high resilience. Patent No. CN113174654A discloses a polyamide-based side-by-side composite elastic fiber and its preparation method. This technology melts and side-by-side composite spins a polyamide 6 thermoplastic elastomer with polyamide 6 or polyamide 66 to prepare the fiber, but the process route is complex and the production efficiency is low.

[0005] Patent No. CN110820079A discloses a preparation method of nano-doped polyamide side-by-side elastic composite fibers. This technology melts and blends or in-situ polymerizes, doping one or several of nano-layered silicates, metal compounds, and rare earth compounds into polyamide, and regulating the molecular interaction between the components of the composite fiber to prepare polyamide self-crimping side-by-side composite fibers. However, this method requires the introduction of expensive materials, with high costs and complex processes. Summary of the Invention

[0006] The object of the present invention is to provide a preparation method of composite high-elastic polyamide FDY filaments, which can melt and side-by-side composite spin PA6 chips and PA56 chips by utilizing the shrinkage rate difference between them, and construct fibers with high elasticity, high strength, good dimensional stability, and excellent comprehensive performance to meet the needs of high-performance textile applications.

[0007] To achieve the above object, the present invention provides the following technical solution: A method for preparing a composite high-elastic polyamide FDY filament, comprising the following steps:

[0008] Step 1: Compress, melt, and homogenize PA6 chips and PA56 chips respectively through two screw extruders to obtain two kinds of melts;

[0009] Step 2: Let the two kinds of melts flow through a metering pump, a flow guide plate, metal sand, and a distribution plate in a spinning pack respectively, and then compound and extrude at a side-by-side spinneret to form a melt stream;

[0010] Step 3: Cool and solidify the melt stream by side blowing, and after bundling and oiling, obtain a nascent fiber;

[0011] Step 4: Prepare a composite high-elastic polyamide FDY filament from the nascent fiber through a draw-winding integrated machine.

[0012] Further, in the step 1, the mass percentage of PA6 chips to PA56 chips is 40%:60% to 60%:40%, and the PA6 chips and PA56 chips are respectively one of dull, semi-dull, and bright.

[0013] Further, in the step 1, in the screw extruder, the temperatures of the first to fifth zones of PA6 chips are respectively controlled at 245-250°C, 247-255°C, 248-255°C, 250-260°C, 253-260°C, and after compression, melting, and homogenization, a PA6 melt is obtained; in the screw extruder, the temperatures of the first to fifth zones of PA56 chips are respectively 258-270°C, 260-275°C, 265-280°C, 270-280°C, 275-280°C, and after compression, melting, and homogenization, a PA56 melt is obtained.

[0014] Further, in the step 2, the two kinds of melts respectively flow through the metering pump at a frequency of 12-40 Hz, the specification of the metal sand filter material in the spinning pack is 35 / 45 mesh to 60 / 80 mesh, and the pressure of the spinning pack is 110-210 pa.

[0015] Further, in the step 2, a plurality of round hole pairs composed of 2 small holes closely adjacent are evenly distributed on the side-by-side spinneret, and the two kinds of melts are respectively extruded from the adjacent small holes at the same time, and are compounded at the spinneret outlet to form a melt stream with a side-by-side structure.

[0016] Further, in the step 3, the side blowing temperature is 19-23°C, the wind speed is 0.45-0.55 m / s, the frequency of the oil agent gear pump in the bundling and oiling is 35-70 Hz, and the vertical distance between the oiling point and the spinneret is 600-1200 mm.

[0017] Further, step 4 is further as follows: the virgin fibers are pre-networked and held together, stretched and heat-set through three godets, and further strengthened in terms of holding together by the main network. Finally, they are wound and formed by a winding machine.

[0018] Further, in step 4, the pre-network air pressure is 1.1 - 1.4 bar, and the main network air pressure is 3.4 - 3.7 bar; three godets are used in the stretching and heat-setting process. The speed of the first godet is 3000 - 3900 m / min, the speed of the second godet is 4000 - 4800 m / min, and the speed of the third godet is 4000 - 4700 m / min; the heating temperature of the second godet is 145°C - 170°C; the winding speed of the winding machine is 3900 - 4800 m / min, and the winding forming angle is 5.3 - 7.5.

[0019] Advantages of the present invention: Based on the significant difference in the number of hydrogen bonds between PA6 chips and PA56 chips, and taking advantage of the unique performance advantages resulting from the difference in shrinkage rate between the two, the present invention innovatively adopts the melt side-by-side composite spinning technology. Through the interlocking and complementary process parameters of each step, composite fibers with high elasticity, high strength, excellent dimensional stability and outstanding comprehensive performance are successfully prepared. Compared with the prior art, the present invention effectively solves the problems of complex traditional preparation processes, high costs and insufficient fiber performance. Without adding any additives, it has low costs and is suitable for industrialized large-scale production by the company, not limited to small-scale tests for scientific research, providing a brand-new technical solution. At the same time, the present invention opens up a new path for the development of functional and differentiated fibers, significantly improves the application value of the fibers, and has broad market prospects and considerable economic benefits. Description of the Drawings

[0020] Figure 1 is the cross-sectional view of the fiber in Example 1.

[0021] Figure 2 is the cross-sectional view of the fiber in Example 2.

[0022] Figure 3 is the partial view of the fiber in Example 2.

[0023] Figure 4 is the structural schematic diagram of the spinneret.

[0024] Figure 5 is the sectional view of the spinneret.

[0025] Wherein: 1, spinneret; 2, pair of round holes; 3, outlet. Detailed Embodiments

[0026] The present invention will be further described below with reference to the drawings.

[0027] Please refer toFigures 1 to 5 , the present invention provides an embodiment: a method for preparing a composite high-elastic polyamide FDY filament, comprising the following steps:

[0028] Step 1: Compress, melt, and homogenize PA6 chips and PA56 chips respectively through two screw extruders to obtain two kinds of melts;

[0029] Step 2: Let the two kinds of melts flow through a metering pump, a deflector plate, metal sand, and a distribution plate in a spinning pack respectively, and then compound and extrude at a side-by-side spinneret 1 to form melt filaments;

[0030] Step 3: Cool and solidify the melt filaments by side air blowing, and after bundling and oiling, obtain nascent fibers;

[0031] Step 4: Prepare the composite high-elastic polyamide FDY filament from the nascent fibers through a draw-winding integrated machine.

[0032] Please continue to refer to Figures 1 to 5 As shown, in one embodiment of the present invention, in the said Step 1, the mass percentage of PA6 chips to PA56 chips is 40%:60% to 60%:40%, and the PA6 chips and PA56 chips are respectively one of dull, semi-dull, and bright. When the ratio is 70%:30% or 30%:70%, the spinning condition is extremely poor and it is impossible to wind into filaments, while in the ratio range of 40%:60% to 60%:40%, the spinning condition is better.

[0033] Please continue to refer to Figures 1 to 5 As shown, in one embodiment of the present invention, in the said Step 1, in the screw extruder, the temperatures of the first to fifth zones of PA6 chips are respectively controlled at 245 - 250°C, 247 - 255°C, 248 - 255°C, 250 - 260°C, 253 - 260°C, and after compression, melting, and homogenization, PA6 melt is obtained; in the screw extruder, the temperatures of the first to fifth zones of PA56 chips are respectively 258 - 270°C, 260 - 275°C, 265 - 280°C, 270 - 280°C, 275 - 280°C, and after compression, melting, and homogenization, PA56 melt is obtained. By setting the above temperatures, the risk of material blockage in the screw extruder can be reduced, and the manual time consumption can be reduced.

[0034] Please continue to refer to Figures 1 to 5 As shown, in one embodiment of the present invention, in the said Step 2, the frequencies of the metering pumps through which the two kinds of melts flow are 12 - 40 Hz respectively, the specification of the metal sand filter material in the spinning pack is 35 / 45 mesh - 60 / 80 mesh, and the pressure of the spinning pack is 110 - 210 pa.

[0035] Please continue to refer to Figure 4 , Figure 5As shown in the figure, in one embodiment of the present invention, in the step 2, a plurality of round hole pairs 2 each composed of two closely adjacent small holes are evenly distributed on the coaxial spinneret 1. Two kinds of melts are respectively extruded from the adjacent small holes at the same time, and are compounded at the outlet 3 of the spinneret 1 to form a melt stream with a coaxial structure. The round hole pair 2 composed of two closely adjacent small holes has a coaxial structure, which enables the respective characteristics of PA6 and PA56 to be maintained and the fiber crimping effect to be achieved.

[0036] Please continue to refer to Figures 1 to 5 As shown in the figure, in one embodiment of the present invention, in the step 3, the side blowing temperature is 19 - 23°C, the wind speed is 0.45 - 0.55 m / s, the frequency of the oil agent gear pump in the bunching and oiling is 35 - 70 Hz, and the vertical distance between the oiling point and the spinneret 1 is 600 - 1200 mm.

[0037] Please continue to refer to Figure 5 As shown in the figure, in one embodiment of the present invention, the step 4 is further as follows: the nascent fiber is pre-networked and held together, stretched and heat-set through three godets, and further strengthened in terms of the holding together property through the main network, and finally wound and formed by a winder.

[0038] Please continue to refer to Figures 1 to 5 As shown in the figure, in one embodiment of the present invention, in the step 4, the pre-network air pressure is 1.1 - 1.4 bar, and the main network air pressure is 3.4 - 3.7 bar; three godets are used in the stretching and heat-setting process. The speed of the first godet is 3000 - 3900 m / min, the speed of the second godet is 4000 - 4800 m / min, and the speed of the third godet is 4000 - 4700 m / min; the heating temperature of the second godet is 145°C - 170°C; the winding speed of the winder is 3900 - 4800 m / min, and the winding forming angle is 5.3 - 7.5.

[0039] Example 1:

[0040] (1) The delustered (FD) PA6 chips with a mass percentage of 50% and the delustered (FD) PA56 chips with a mass percentage of 50% enter the screw extruder simultaneously and respectively.

[0041] (2) The PA6 chips are melted, compressed and homogenized in a screw extruder with the temperatures in zones 1 - 5 being 245°C, 248°C, 250°C, 253°C, 256°C respectively, and the diphenyl temperature being 255°C; at the same time, the PA56 chips are melted, compressed and homogenized in a screw extruder with the temperatures in zones 1 - 5 being 265°C, 268°C, 270°C, 274°C, 278°C respectively, and the diphenyl temperature being 278°C.

[0042] (3) The PA6 melt is regulated by a metering pump with a frequency of 20.18 Hz, and the PA56 melt is regulated by a metering pump with a frequency of 15.12 Hz. Subsequently, 50 g of a 60 / 80 mesh metal sand filter material is used for the PA6 melt, and 100 g of a 60 / 80 mesh metal sand filter material is used for the PA56 melt. The aspect ratio of the micropores in the spinneret is 3. The component pressure of the PA6 melt is 116 pa, and the component pressure of the PA56 melt is 108 pa;

[0043] (4) The side blow air temperature is 22 °C, the wind speed is 0.45 m / s, the oil agent concentration is 7%, the frequency of the oil agent gear pump is 40 Hz, and the vertical distance from the oil application and bundling point to the spinneret is 700 mm to obtain the nascent fiber;

[0044] (5) The nascent fiber is pre-networked and held together. The pre-network air pressure is 1.30 bar. The speed of the first godet roller is 3200 m / min, the speed of the second godet roller is 4530 m / min, and the speed of the third godet roller is 4510 m / min. The heating temperature of the second godet roller in the heat setting is 150 °C. The main network air pressure is 3.65 bar, the winding speed is 4500 m / min, the starting value of the winding forming angle is 5.5, and the winding forming angles during the winding movement are 5.8, 6.1, 6.5, 6.8, 6.5, 6.2, 5.8, 5.5, 5.3 in sequence, to prepare 40D / 24F FD composite high elastic polyamide FDY filaments. The cross-section is shown in Figure 1 as shown.

[0045] Example 2:

[0046] (1) 50% by mass of semi-dull (SD) PA6 chips and 50% by mass of delustered (FD) PA56 chips enter the screw extruder simultaneously and separately;

[0047] (2) The PA6 chips are melted, compressed, and homogenized in a screw extruder with temperatures in zones 1 to 5 being 248 °C, 250 °C, 253 °C, 256 °C, and 258 °C respectively, and the diphenyl temperature is 258 °C. At the same time, the PA56 chips are melted, compressed, and homogenized in a screw extruder with temperatures in zones 1 to 5 being 260 °C, 273 °C, 276 °C, 278 °C, and 280 °C respectively, and the diphenyl temperature is 280 °C;

[0048] (3) The PA6 melt is regulated by a metering pump with a frequency of 25.21 Hz, and the PA56 melt is regulated by a metering pump with a frequency of 18.90 Hz. Subsequently, 50 g of a 60 / 80 mesh metal sand filter material is used for the PA6 melt, and 100 g of a 60 / 80 mesh metal sand filter material is used for the PA56 melt. The aspect ratio of the micropores in the spinneret is 3. The component pressure of the PA6 melt is 149 pa, and the component pressure of the PA56 melt is 150 pa;

[0049] (4) The side blowing air temperature is 22.5 °C, the wind speed is 0.45 m / s, the oil agent concentration is 7%, the frequency of the oil agent gear pump is 45 Hz, and the vertical distance from the oil application bundling point to the spinneret is 800 mm, obtaining the nascent fiber;

[0050] (5) The nascent fiber is subjected to pre-network coiling. The pre-network air pressure is 1.30 bar, the speed of the first godet roller is 3600 m / min, the speed of the second godet roller is 4515 m / min, the speed of the third godet roller is 4495 m / min, the heating temperature of the second godet roller in heat setting is 150 °C, the main network air pressure is 3.65 bar, the winding speed is 4500 m / min, the starting value of the winding forming angle is 5.8, and the winding forming angles following the winding movement are 6.3, 6.6, 7.0, 7.3, 7.0, 6.7, 6.3, 6.0, 5.8 in sequence, preparing 50D / 24F SD composite high elastic polyamide FDY filaments, and the cross-section is shown in Figure 2 as shown.

[0051] The above are only the preferred embodiments of the present invention, and should not be construed as limitations to this application. All equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope covered by the present invention.

Claims

1. A preparation method of a composite highly elastic polyamide FDY filament, characterized in that: It includes the following steps: Step 1: Compress, melt, and homogenize PA6 chips and PA56 chips respectively through two screw extruders to obtain two kinds of melts; Step 2: Let the two kinds of melts flow through a metering pump, a deflector plate, metal sand, and a distribution plate in a spinning pack respectively, and then compound and extrude at a side-by-side spinneret to form melt filaments; Step 3: Cool and solidify the melt filaments by side blowing, and after bundling and oiling, obtain virgin fibers; Step 4: Prepare composite high-elastic polyamide FDY filaments from the virgin fibers through a drawing and winding integrated machine.

2. The preparation method of a composite highly elastic polyamide FDY filament according to claim 1, characterized in that: In the said Step 1, the mass percentage of PA6 chips to PA56 chips is 40%:60% to 60%:40%, and the PA6 chips and PA56 chips are respectively one of dull, semi-dull, and bright.

3. The preparation method of a composite high-elastic polyamide FDY filament according to claim 1, characterized in that: In the said Step 1, in the screw extruder, the temperatures of the first to fifth zones of PA6 chips are respectively controlled at 245 - 250°C, 247 - 255°C, 248 - 255°C, 250 - 260°C, 253 - 260°C, and after compression, melting, and homogenization, PA6 melt is obtained; in the screw extruder, the temperatures of the first to fifth zones of PA56 chips are respectively 258 - 270°C, 260 - 275°C, 265 - 280°C, 270 - 280°C, 275 - 280°C, and after compression, melting, and homogenization, PA56 melt is obtained.

4. The preparation method of a composite high-elastic polyamide FDY filament according to claim 1, characterized in that: In the said Step 2, the two kinds of melts respectively flow through a metering pump with a frequency of 12 - 40 Hz, the metal sand filter material in the spinning pack has a specification of 35 / 45 mesh to 60 / 80 mesh, and the pressure of the spinning pack is 110 - 210 Pa.

5. The preparation method of a composite high-elastic polyamide FDY filament according to claim 1, characterized in that, In the said Step 2, a plurality of round hole pairs composed of 2 small holes closely adjacent are evenly distributed on the side-by-side spinneret, and the two kinds of melts are respectively extruded from the adjacent small holes at the same time, and are compounded at the spinneret outlet to form a melt filament with a side-by-side structure.

6. The preparation method of a composite high-elastic polyamide FDY filament according to claim 1, characterized in that: In the said Step 3, the side blowing temperature is 19 - 23°C, the wind speed is 0.45 - 0.55 m / s, the frequency of the oil agent gear pump in the bundling and oiling is 35 - 70 Hz, and the vertical distance from the oiling point to the spinneret is 600 - 1200 mm.

7. The preparation method of a composite high-elastic polyamide FDY filament according to claim 7, characterized in that: The said Step 4 is further that the virgin fibers are pre-networked and held together, stretched and heat-set through three godets, and further strengthened in terms of holding together by a main network, and finally wound and formed by a winder.

8. The preparation method of a composite high-elastic polyamide FDY filament according to claim 7, characterized in that: In the said Step 4, the pre-network air pressure is 1.1 - 1.4 bar, and the main network air pressure is 3.4 - 3.7 bar; three godets are used in the stretching and heat-setting process, the speed of the first godet is 3000 - 3900 m / min, the speed of the second godet is 4000 - 4800 m / min, the speed of the third godet is 4000 - 4700 m / min; the heating temperature of the second godet is 145°C - 170°C; the winding speed of the winder is 3900 - 4800 m / min, and the winding forming angle is 5.3 - 7.5.

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