Method and texturing apparatus for preparing PBT-DTY matte elastic memory fiber filaments

Abstract

This invention discloses a method for preparing PBT-DTY matte elastic memory fiber filaments and a texturing preparation apparatus. The preparation method includes the following steps: S1, PBT polyester melt preparation; S2, PBT direct spinning; S3, PBT-POY fiber texturing. The texturing preparation apparatus includes a specific heating box comprising a cylindrical body. Several guide rails are provided in the lower middle part of the box, and a guide device is provided at each end of the box. A main nitrogen pipe is provided on each of the two side walls of the box corresponding to the front end of the front section of the heating zone, and an auxiliary nitrogen pipe is provided on the top of the box corresponding to the front end of the rear section of the heating zone. This invention employs a melt direct spinning process, which has the advantages of a short process flow, low unit output infrastructure investment costs, low energy consumption, and low product cost. Furthermore, the PBT-POY fibers exhibit uniform tension, good evenness, few fuzz, and large package size, offering greater flexibility in post-processing. This allows the fiber filaments to evaporate and decompose oils as much as possible during their entry into the long rear section of the heating zone, while ensuring uniform heating.

Description

Technical Field

[0001] This invention relates to the field of PBT melt spinning technology, specifically to a method for preparing PBT-DTY matte elastic memory fiber filaments and a texturing preparation device. Background Technology

[0002] Polybutylene terephthalate (PBT) is a polyester produced by the polycondensation of terephthalic acid and 1,4-butanediol, and is an important thermoplastic polyester. There are two main methods for PBT production: transesterification and direct esterification polycondensation. Direct esterification polycondensation is more economical and widely used, but because the process involves materials in a high-temperature, high-vacuum molten state, it is more complex in terms of equipment materials, equipment structure, material conveying, and reaction condition control. Therefore, several patented technologies have been developed. A well-known example is the Lurgi Zemmer technology, which uses three reactors: esterification, pre-polymerization, and polycondensation. The polycondensation reactor is a horizontal disc reactor, and a single production line can reach a capacity of 120,000 tons / year. The products are of high quality, and the byproduct tetrahydrofuran can be directly used in the production of polytetrahydrofuran. The Japanese Hitachi technology has four different types of reactors, which can simultaneously produce both high-viscosity and medium-viscosity products, with a single production line capacity of up to 60,000 tons / year. The Uhde Inyenta Fischer technology uses a tower reactor, where esterification and polycondensation can be completed in one reactor, producing PBT products with a degree of polymerization of 20-35. If products with a degree of polymerization of 80-150 are to be produced, the process can be moved to another horizontal polycondensation reactor called DISCAGE.

[0003] The development of filament spinning technology has progressed from conventional spinning to high-speed and ultra-high-speed spinning, from small-capacity to large-capacity spinning, and from chip spinning to melt direct spinning. Among these advancements, high-speed spinning, especially melt direct spinning, has seen continuous improvement, and the widespread adoption of the direct spinning process route represents the most revolutionary progress. Melt direct spinning offers advantages such as a shorter process flow, lower infrastructure investment per unit output, and lower energy consumption and product costs. However, direct spinning requires high levels of process continuity, stability, and uniformity. Due to limitations in melt pipe length, production operations have limited flexibility, and products cannot be frequently changed. Furthermore, it demands a high level of operational and management expertise. This is particularly true when using high-speed spinning and winding processes to produce pre-oriented yarn (POY) to prepare PBT-DTY matte elastic memory fiber filaments, where the operational steps and equipment requirements become even more precise. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing PBT-DTY matte elastic memory fiber filaments and a texturing preparation apparatus.

[0005] The technical solution of this invention is:

[0006] The method for preparing PBT-DTY matte elastic memory fiber includes the following steps:

[0007] S1. Preparation of PBT polyester melt: By weight, 1 part of purified terephthalic acid solid powder and 2-3 parts of 1,4-butanediol solution are mixed and stirred, then added to the esterification reactor. 0.02 parts by weight of catalyst are added to carry out the esterification reaction. The material is then transported to the prepolymerization reactor for preliminary polycondensation reaction under a vacuum of 2 kPa. The material is then transported to the final polymerization reactor for film stretching polycondensation reaction under a vacuum of 150 Pa to obtain PBT polyester melt.

[0008] S2, PBT direct spinning: The PBT polyester melt obtained in step S1 is transported to the spinning box through a melt booster pump. The PBT polyester melt is extruded and then air-cooled and shaped, then bundled and oiled, and wound to form PBT-POY fiber.

[0009] S3. PBT-POY Fiber Texturing: The PBT-POY fibers obtained in step S2 are sequentially processed through a primary roller, a primary hot box deformation, a cooling plate, a false twister for twisting and untwisting, a secondary roller, a secondary hot box setting, a mesh nozzle to increase the mesh density, and a tertiary roller to obtain PBT-DTY matte fiber filaments. The draw ratio of the secondary roller to the primary roller is 1.16–1.18. In the primary hot box deformation, a specific hot box is divided into a front hot zone and a rear hot zone. The front section of the hot zone occupies 1 / 4 ± 1 / 8 of the total specific hot zone, and the rear section occupies 3 / 4 ± 1 / 8 of the total specific hot zone. The set temperature of the front section is 280-300℃, and the set temperature of the rear section is 220-240℃. At the same time, nitrogen is introduced into the specific hot zone during one hot zone deformation. In the front section, the nitrogen temperature is 30-40℃ lower than the set temperature of the front section, and in the rear section, the nitrogen temperature is 10-20℃ lower than the set temperature of the rear section.

[0010] Furthermore, in step S1, the catalyst is tetrabutyl titanate, the esterification reaction is carried out under negative pressure, the stirring speed is 100-150 rpm, and the stirring time is 30-60 min.

[0011] Note: Acetic acidification is a reversible reaction, so the small molecules produced in the reaction must be removed before the forward reaction can proceed. Therefore, the entire reaction process is carried out under negative pressure.

[0012] Furthermore, in step S2, the delivery pressure of the melt booster pump is 1-5 MPa, the delivery temperature is 320-340°C, and the extrusion temperature is 280-320°C.

[0013] Note: Optimal pressure and temperature for melt pumping are used to prevent melt degradation.

[0014] Furthermore, in step S3, the nitrogen pressure is 0.005-0.2 bar, and the set temperature for the secondary heating chamber is 50-100℃.

[0015] Note: By filling the hot box with nitrogen, oxidation of PBT-POY fibers can be avoided. Optimizing the nitrogen injection temperature and pressure can minimize the risk of the hot box temperature dropping too much due to the injected nitrogen, which could cause a significant decrease in the processing temperature of PBT-POY fibers.

[0016] This invention also provides a texturing preparation apparatus used in the preparation method of PBT-DTY matte elastic memory fiber filaments, including a specific heating box. The specific heating box includes a cylindrical box body. A first heating plate is provided at the bottom of the box body corresponding to the front section of the heating zone, and a second heating plate is provided at the bottom of the box body corresponding to the rear section of the heating zone. Several guide rails are provided in the lower middle part of the box body. A guide device is provided at each end of the box body. The guide device at the front end guides the PBT-POY fiber into each of the guide rails. A main nitrogen pipe is provided on each of the two side walls of the box body corresponding to the front end of the front section of the heating zone, and a main nitrogen pipe is provided on the top of the box body corresponding to the rear section of the heating zone. An auxiliary nitrogen pipe is provided at the front end of the hot zone. The bottom of the auxiliary nitrogen pipe passes through the bottom of the top wall of the box and is provided with several rotating fan blades for guiding nitrogen. A first upper guide plate and a first lower guide plate are symmetrically arranged on both sides of the inner wall of the box, corresponding to the front hot zone. The outlet of the main nitrogen pipe is located between the first upper guide plate and the first lower guide plate. A second upper guide plate and a second lower guide plate are symmetrically arranged on both sides of the inner wall of the box, corresponding to the rear hot zone. The connection between the second upper guide plate and the second lower guide plate and the first upper guide plate and the first lower guide plate is a nitrogen mixing section. The rotating fan blades are located in the nitrogen mixing section.

[0017] Furthermore, a hollow fixed rod is provided below the auxiliary nitrogen pipe located inside the housing. A hollow rotating rod is rotatably connected to the bottom of the hollow fixed rod. The hollow rotating rod has several through holes in its middle, which communicate with the interior of the hollow fixed rod. A hollow turntable is provided at the rear end of the hollow rotating rod. Rotating fan blades are evenly spaced on the side wall of the hollow turntable, and the hollow turntable communicates with the interior of the rotating fan blades. An exhaust hole is provided at the end of the rotating fan blades, so that the nitrogen inside the auxiliary nitrogen pipe passes sequentially through the interior of the hollow fixed rod, the through holes, the interior of the hollow rotating rod, and the hollow turntable. The gas is ejected from the interior of the rotating fan blades and then from the outlet. A connecting rod is located at the center of the rear side of the hollow turntable, and the end of the connecting rod is provided with a first bevel tooth. A drive motor for driving the rotation of the hollow turntable is located at the top of the box corresponding to the rear of the auxiliary nitrogen pipe. The output end of the drive motor is provided with a drive rod that penetrates through the top of the box. The bottom of the drive rod is provided with a second bevel tooth, which meshes with the first bevel tooth for rotatable connection. A return pipe is provided on the upper part of the rear side wall of the box. A heater is provided in the middle of both the main nitrogen pipe and the auxiliary nitrogen pipe. The return pipe is connected to the heater on the auxiliary nitrogen pipe.

[0018] Explanation: The drive motor drives the drive rod to rotate, which in turn drives the hollow turntable and the rotating fan blades to rotate, promoting the mixing of two nitrogen gases at different temperatures, thereby achieving the temperature transition from the front hot zone to the rear hot zone. The rotation of the fan blades also promotes the flow of nitrogen gas inside the chamber.

[0019] Furthermore, a rotating ring is provided on the front side of the hollow rotating rod, and a rotating groove is provided on the front side of the bottom of the hollow fixed rod. The rotating ring is rotatably connected to the rotating groove. A limiting block is provided on the front side of the bottom of the hollow fixed rod above the rotating groove. The bottom of the limiting block extends into the rotating groove to prevent the rotating ring from coming out.

[0020] Explanation: The setting of the limit block enables the rotating ring to rotate stably within the rotating groove, thereby maintaining the stability of the rotating fan blades and the hollow turntable.

[0021] Furthermore, the length of the nitrogen mixing section is 1 / 16 of the length of the casing.

[0022] Note: By optimizing the length of the nitrogen mixing section, the mixing of two nitrogen gases at different temperatures is made more uniform and stable, preventing a significant drop in the processing temperature of PBT-POY fibers at that location.

[0023] Furthermore, the second upper guide plate has an arc-shaped notch on one side corresponding to the nitrogen mixing section, and the guide wire hot rail is V-shaped, with a total of three guide wire hot rails.

[0024] The beneficial effects of this invention are:

[0025] (1) The method for preparing PBT-DTY matte elastic memory fiber filaments of the present invention adopts melt direct spinning process, which has the advantages of short process flow, low unit output infrastructure investment cost, low energy consumption and product cost; the high-speed spinning and winding process is used to produce pre-oriented PBT-POY fiber, which not only saves investment, land area and reduces production cost, but also the PBT-POY fiber has uniform tension, good evenness, less fuzz, large package size, and the product can be stored and transported for a long time, and has greater flexibility in post-processing; finally, the texturing process of PBT-POY fiber is optimized, especially the stretch ratio of the secondary roller and the primary roller is optimized, and the specific hot box in the primary hot box deformation is divided into a front hot zone and a rear hot zone, so that the fiber filaments can evaporate and decompose the oil agent as much as possible when entering the long rear hot zone, and ensure uniform heating.

[0026] (2) The method for preparing PBT-DTY matte elastic memory fiber filament of the present invention fills the hot box with nitrogen by injecting nitrogen during the deformation of the hot box, which can avoid oxidation of PBT-POY fiber. Preferably, the temperature and pressure of nitrogen injection can minimize the risk of the hot box temperature dropping too much due to the injected nitrogen, thus avoiding a significant reduction in the processing temperature of PBT-POY fiber.

[0027] (3) The PBT-DTY matte elastic memory fiber filament preparation device of the present invention provides a proprietary specific hot box based on the temperature setting in the primary hot box deformation of the present invention method. The drive motor drives the drive rod to rotate, thereby driving the hollow turntable and the rotating fan blade to rotate, promoting the mixing of two nitrogen gases at different temperatures, thereby realizing the temperature transition from the front hot zone to the rear hot zone. The rotation of the rotating fan blade can also promote the flow of nitrogen gas inside the box. The setting of the limiting block can make the rotating ring rotate stably in the rotating groove, thereby maintaining the stability of the rotating fan blade and the hollow turntable. By optimizing and adjusting the length of the nitrogen gas mixing section, the mixing of two nitrogen gases at different temperatures is more uniform and stable, and the processing temperature of PBT-POY fiber at this position will not drop significantly. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the PBT-DTY matte elastic memory fiber filament texturing preparation device of the present invention;

[0029] Figure 2 This is a schematic diagram of the rear internal structure of the PBT-DTY matte elastic memory fiber filament texturing preparation device of the present invention;

[0030] Figure 3 This is a schematic diagram of the internal structure of the PBT-DTY matte elastic memory fiber filament texturing preparation device of the present invention;

[0031] Figure 4 This is a schematic diagram of the rear internal structure of the PBT-DTY matte elastic memory fiber filament texturing preparation device of the present invention;

[0032] Figure 5 This is a schematic diagram of the internal structure of the nitrogen mixing section of the PBT-DTY matte elastic memory fiber filament texturing preparation device of the present invention;

[0033] Figure 6 This is a schematic diagram of the internal structure of the hollow rotating rod in the PBT-DTY matte elastic memory fiber filament texturing preparation device of the present invention;

[0034] Figure 7 This is a schematic diagram of the connection between the rotating ring and the rotating groove of the PBT-DTY matte elastic memory fiber filament texturing preparation device of the present invention;

[0035] Figure 8 This is a schematic diagram of the internal structure of the rotating fan blade of the PBT-DTY matte elastic memory fiber filament texturing preparation device of the present invention.

[0036] Among them, 1-box body, 11-first heating plate, 12-second heating plate, 13-first upper guide plate, 14-first lower guide plate, 15-second upper guide plate, 151-arc-shaped notch, 16-second lower guide plate, 17-return pipe, 2-guide wire hot rail, 3-guide wire device, 4-main nitrogen pipe, 5-auxiliary nitrogen pipe, 51-hollow fixing rod, 52-hollow rotating rod, 53-through hole, 54-hollow turntable, 55-rotating ring, 56-rotating groove, 57-limiting block, 6-rotating fan blade, 61-air outlet, 62-connecting rod, 63-first bevel tooth, 7-drive motor, 71-drive rod, 72-second bevel tooth, 8-heater. Detailed Implementation

[0037] Example 1

[0038] The method for preparing PBT-DTY matte elastic memory fiber includes the following steps:

[0039] S1. Preparation of PBT polyester melt: By weight, 1 part of purified terephthalic acid solid powder and 2.5 parts of 1,4-butanediol solution are mixed and stirred, then added to the esterification reactor. 0.02 parts by weight of catalyst are added to carry out the esterification reaction. The material is then transferred to the prepolymerization reactor for preliminary polycondensation reaction under a vacuum of 2 kPa. The material is then transferred to the final polymerization reactor for film stretching polycondensation reaction under a vacuum of 150 Pa to obtain PBT polyester melt. The catalyst is tetrabutyl titanate. The esterification reaction is carried out under negative pressure. The stirring speed is 120 rpm and the stirring time is 40 min.

[0040] S2, PBT direct spinning: The PBT polyester melt obtained in step S1 is transported to the spinning box 1 through a melt booster pump. The PBT polyester melt is extruded and then air-cooled and shaped, then bundled and oiled, and wound to form PBT-POY fibers. The conveying pressure of the melt booster pump is 2MPa, the conveying temperature is 330℃, and the extrusion temperature is 300℃.

[0041] S3. PBT-POY Fiber Texturing: The PBT-POY fibers obtained in step S2 are sequentially processed through a primary roller, a primary hot box deformation, a cooling plate, a false twister for twisting and untwisting, a secondary roller, a secondary hot box setting, a mesh nozzle to increase the mesh density, and a tertiary roller to obtain PBT-DTY matte fiber filaments. The draw ratio of the secondary roller to the primary roller is 1.17. In the primary hot box deformation, the specific hot box is divided into a front hot zone and a rear hot zone. The front hot zone... The front section accounts for 1 / 4 of the total specific hot zone, while the rear section accounts for 3 / 4. The set temperature of the front section is 290℃, and the set temperature of the rear section is 230℃. Nitrogen is introduced into the specific hot zone during the first hot zone deformation. The nitrogen temperature in the front section is 35℃ lower than the set temperature of the front section, and the nitrogen temperature in the rear section is 15℃ lower than the set temperature of the rear section. The nitrogen pressure is 0.1 bar. The set temperature for the second hot zone shaping is 75℃.

[0042] Example 2

[0043] The difference between this embodiment and Embodiment 1 is that the specific parameter settings are different.

[0044] By weight, 1 part of purified terephthalic acid solid powder and 2 parts of 1,4-butanediol solution were mixed and stirred, then added to an esterification reactor. 0.02 parts by weight of catalyst were added to carry out the esterification reaction. The material was then transferred to a prepolymerization reactor for a preliminary polycondensation reaction under a vacuum of 2 kPa. The material was then transferred to a final polymerization reactor for a film stretching polycondensation reaction under a vacuum of 150 Pa to obtain PBT polyester melt. The catalyst was tetrabutyl titanate. The esterification reaction was carried out under negative pressure. The stirring speed was 100 rpm and the stirring time was 30 min.

[0045] S2, PBT direct spinning: The PBT polyester melt obtained in step S1 is transported to the spinning box 1 through a melt booster pump. The PBT polyester melt is extruded and then air-cooled and shaped, then bundled and oiled, and wound to form PBT-POY fibers. The conveying pressure of the melt booster pump is 1MPa, the conveying temperature is 320℃, and the extrusion temperature is 280℃.

[0046] S3. PBT-POY Fiber Texturing: The PBT-POY fibers obtained in step S2 are sequentially processed through a primary roller, a primary hot box deformation, a cooling plate, a false twister for twisting and untwisting, a secondary roller, a secondary hot box setting, a mesh nozzle to increase the mesh density, and a tertiary roller to obtain PBT-DTY matte fiber filaments. The draw ratio of the secondary roller to the primary roller is 1.16. In the primary hot box deformation, the specific hot box is divided into a front hot zone and a rear hot zone, with the front hot zone accounting for [percentage missing]. The total specific hot zone accounts for 3 / 8 of the total specific hot zone, and the rear hot zone accounts for 5 / 8 of the total specific hot zone. The set temperature of the front hot zone is 280℃, and the set temperature of the rear hot zone is 220℃. At the same time, nitrogen is introduced into the specific hot zone during the first hot zone deformation. In the front hot zone, the nitrogen temperature is 30℃ lower than the set temperature of the front hot zone, and in the rear hot zone, the nitrogen temperature is 10℃ lower than the set temperature of the rear hot zone. The nitrogen pressure is 0.005 bar. The set temperature of the second hot zone shaping is 50℃.

[0047] Example 3

[0048] The difference between this embodiment and Embodiment 1 is that the specific parameter settings are different.

[0049] By weight, 1 part of purified terephthalic acid solid powder and 3 parts of 1,4-butanediol solution were mixed and stirred, then added to an esterification reactor. 0.02 parts by weight of catalyst were added to carry out the esterification reaction. The material was then transferred to a prepolymerization reactor for a preliminary polycondensation reaction under a vacuum of 2 kPa. The material was then transferred to a final polymerization reactor for a film stretching polycondensation reaction under a vacuum of 150 Pa to obtain PBT polyester melt. The catalyst was tetrabutyl titanate. The esterification reaction was carried out under negative pressure. The stirring speed was 150 rpm and the stirring time was 60 min.

[0050] S2, PBT direct spinning: The PBT polyester melt obtained in step S1 is transported to the spinning box 1 through a melt booster pump. The PBT polyester melt is extruded and then air-cooled and shaped, then bundled and oiled, and wound to form PBT-POY fibers. The conveying pressure of the melt booster pump is 5MPa, the conveying temperature is 340℃, and the extrusion temperature is 320℃.

[0051] S3. PBT-POY Fiber Texturing: The PBT-POY fibers obtained in step S2 are sequentially processed through a primary roller, a primary hot box deformation, a cooling plate, a false twister for twisting and untwisting, a secondary roller, a secondary hot box setting, a mesh nozzle to increase the mesh density, and a tertiary roller to obtain PBT-DTY matte fiber filaments. The draw ratio of the secondary roller to the primary roller is 1.18. In the primary hot box deformation, the specific hot box is divided into a front hot zone and a rear hot zone. The front hot zone... The front section accounts for 1 / 8 of the total specific hot zone, while the rear section accounts for 7 / 8. The set temperature of the front section is 300℃, and the set temperature of the rear section is 240℃. Nitrogen is introduced into the specific hot zone during the first hot zone deformation. The nitrogen temperature in the front section is 40℃ lower than the set temperature of the front section, and the nitrogen temperature in the rear section is 20℃ lower than the set temperature of the rear section. The nitrogen pressure is 0.2 bar. The set temperature for the second hot zone shaping is 100℃.

[0052] Example 4

[0053] This embodiment describes the texturing apparatus used in the PBT-DTY matte elastic memory fiber preparation method of Example 1, such as... Figures 1-3 As shown, the device includes a specific heating box, which comprises a cylindrical box body 1. A first heating plate 11 is located at the bottom of the box body 1 corresponding to the front heating zone, and a second heating plate 12 is located at the bottom of the box body 1 corresponding to the rear heating zone. Three guide wire heating rails 2 are located in the lower middle part of the box body 1, and the guide wire heating rails 2 are V-shaped. A guide wire device 3 is located at each end of the box body 1. The guide wire device 3 at the front end guides PBT-POY fibers into each guide wire heating rail 2. A main nitrogen pipe 4 is located on each of the two side walls of the box body 1 at the front end corresponding to the front end of the front heating zone. An auxiliary nitrogen pipe 5 is located at the top of the box body 1 at the front end corresponding to the rear heating zone. The bottom of the auxiliary nitrogen pipe 5 penetrates the lower part of the top wall of the box body 1 and has several swirls for guiding nitrogen gas. The rotating fan blade 6 is located between the first upper guide plate 13 and the first lower guide plate 14, which are symmetrically arranged on both sides of the inner wall of the housing 1, corresponding to the front hot zone. The outlet of the main nitrogen pipe 4 is located between the first upper guide plate 13 and the first lower guide plate 14. The second upper guide plate 15 and the second lower guide plate 16 are symmetrically arranged on both sides of the inner wall of the housing 1, corresponding to the rear hot zone. The second upper guide plate 15 has an arc-shaped notch 151 on one side corresponding to the nitrogen mixing section. The joint between the second upper guide plate 15 and the second lower guide plate 16 and the first upper guide plate 13 and the first lower guide plate 14 is the nitrogen mixing section. The rotating fan blade 6 is located in the nitrogen mixing section. The length of the nitrogen mixing section is 1 / 16 of the length of the housing 1.

[0054] like Figures 4-6As shown in Figure 8, a hollow fixed rod 51 is located below the auxiliary nitrogen pipe 5 inside the housing 1. A hollow rotating rod 52 is rotatably connected to the bottom of the hollow fixed rod 51. Several through holes 53 are provided in the middle of the hollow rotating rod 52, which communicate with the interior of the hollow fixed rod 51. A hollow turntable 54 is provided at the rear end of the hollow rotating rod 52. Rotating fan blades 6 are evenly spaced on the side wall of the hollow turntable 54, and the hollow turntable 54 communicates with the interior of the rotating fan blades 6. An exhaust hole 61 is provided at the end of the rotating fan blades 6, which allows the nitrogen inside the auxiliary nitrogen pipe 5 to pass sequentially through the interior of the hollow fixed rod 51, the through holes 53, the interior of the hollow rotating rod 52, the interior of the hollow turntable 54, and the rotating fan blades 6. The air is ejected from the interior of the blade 6 through the air outlet 61. A connecting rod 62 is provided at the center of the rear side of the hollow turntable 54. The end of the connecting rod 62 is provided with a first bevel tooth 63. A drive motor 7 for driving the hollow turntable 54 to rotate is provided at the top of the box body 1 corresponding to the rear of the auxiliary nitrogen pipe 5. The drive motor 7 is a commercially available gear reduction motor. The output end of the drive motor 7 is provided with a drive rod 71 that penetrates the top of the box body 1. The bottom of the drive rod 71 is provided with a second bevel tooth 72. The second bevel tooth 72 meshes with the first bevel tooth 63 and rotates. A return pipe 17 is provided on the upper part of the rear side wall of the box body 1. A heater 8 is provided in the middle of both the main nitrogen pipe 4 and the auxiliary nitrogen pipe 5. The return pipe 17 is connected to the heater 8 on the auxiliary nitrogen pipe 5.

[0055] like Figure 7 As shown, a rotating ring 55 is provided on the front side of the hollow rotating rod 52, and a rotating groove 56 is provided on the front side of the bottom of the hollow fixed rod 51. The rotating ring 55 is rotatably connected to the rotating groove 56. A limiting block 57 is provided on the front side of the bottom of the hollow fixed rod 51 above the rotating groove 56. The bottom of the limiting block 57 extends into the rotating groove 56 to prevent the rotating ring 55 from coming out.

[0056] Working principle: The working principle of the texturing preparation device used in the preparation method of PBT-DTY matte elastic memory fiber of the present invention will be briefly explained below.

[0057] In use, the housing 1 is first sealed. The nitrogen inside the main nitrogen pipe 4 is heated by the heater 8 and injected into the front end of the housing 1. The injected nitrogen moves along the front hot zone under the action of the first upper guide plate 13 and the first lower guide plate 14. At the same time, the drive motor 7 is turned on to drive the drive rod 71 to rotate. Under the meshing action of the first bevel gear 63 and the second bevel gear 72, the hollow turntable 54 is rotated. The heater 8 heats the nitrogen inside the auxiliary nitrogen pipe 5 and injects it into the front end of the rear hot zone of the housing 1. The nitrogen enters the through hole 53 through the hollow fixed rod 51. Because the hollow rotating rod 52 rotates continuously, the through holes 53 on the hollow rotating rod 52 rotate continuously until they are connected to the inside of the hollow fixed rod 51, thereby realizing the delivery of nitrogen. It is then delivered to the hollow turntable through the hollow rotating rod 52 and finally sprayed out through the internal space of the rotating fan blade 6 and the air outlet 61. At this time, the nitrogen heated by the heater 8 on the pre-set auxiliary nitrogen pipe 5 is... The temperature must be between the required nitrogen temperatures of the two hot zones (the nitrogen temperature in the first hot zone is 35°C lower than the set temperature of the first hot zone, and the nitrogen temperature in the second hot zone is 15°C lower than the set temperature of the second hot zone). This ensures that the lower-temperature nitrogen mixes with the higher-temperature nitrogen to reach the required nitrogen temperature in the second hot zone. The rotating fan blades 6 continuously rotate to accelerate the mixing of nitrogen and promote the flow of the mixed nitrogen, thereby reaching the required nitrogen temperature in the second hot zone. The second upper guide plate 15 and the second lower guide plate 16 are connected to the first upper guide plate 13 and the first lower guide plate 14, which can form continuous flow inertia. Under the action of the arc-shaped notch 151, the mixed nitrogen can flow well over the surface of the PBT-POY fiber on the guide wire hot rail 2. Finally, the nitrogen is recovered through the return pipe 17 and the internal pressure of the box 1 is adjusted in real time to achieve circulation. The circulated nitrogen is reheated by the heater 8 to reach the required temperature.

[0058] Experimental Example

[0059] The properties of the PBT-DTY matte fiber filament prepared by the method of the present invention are tested below, taking Example 1 as an example. Several comparative examples are also provided.

[0060] The difference between Comparative Example 1 and Example 1 is that the front section of the hot zone accounts for 1 / 3 of the total specific hot zone of the hot box, and the rear section of the hot zone accounts for 2 / 3 of the total specific hot zone of the hot box.

[0061] The difference between Comparative Example 2 and Example 1 is that the set temperature of the front hot zone is 330°C;

[0062] The difference between Comparative Example 3 and Example 1 is that the set temperature of the rear hot zone is 280°C;

[0063] The difference between Comparative Example 4 and Example 1 is that nitrogen gas was not injected.

[0064] The comparison results are shown in the table below:

[0065]

[0066]

[0067] As can be seen from the data in the table, compared with Comparative Example 1, the PBT-DTY matte fiber filament prepared in Example 1 has slightly better performance in all aspects, especially the increased crimp shrinkage rate. This is mainly because the high-temperature section of the front hot zone in Comparative Example 1 is longer, which is unfavorable for subsequent production. Compared with Comparative Example 2, the PBT-DTY matte fiber filament prepared in Example 1 has improved elongation and crimp shrinkage, but reduced breaking strength. This is because Comparative Example 2 uses a higher high-temperature temperature in the front hot zone, which can improve breaking strength, but the overall performance is not as good as Example 1. Further analysis of the data in Comparative Example 3 shows that increasing the set temperature of the rear hot zone can improve the crimp shrinkage rate to a certain extent, but the breaking strength and elongation both decrease. Finally, a comparison of Comparative Example 4 shows that the PBT-DTY matte fiber filament prepared without nitrogen injection has slightly worse performance in all aspects. Therefore, the method parameters in Example 1 are preferred.

Claims

1. A method for preparing PBT-DTY matte elastic memory fiber filaments, characterized in that, Includes the following steps: S1, PBT polyester melt preparation: By weight, 1 part of purified terephthalic acid solid powder and 2-3 parts of 1,4-butanediol solution are mixed and stirred, then added to the esterification reactor. 0.02 parts by weight of catalyst are added to carry out the esterification reaction. The material is then transported to the prepolymerization reactor for preliminary polycondensation reaction under a vacuum of 2 kPa. The material is then transported to the final polymerization reactor for film stretching polycondensation reaction under a vacuum of 150 Pa to obtain PBT polyester melt. S2, PBT direct spinning: The PBT polyester melt obtained in step S1 is transported to the spinning box (1) through a melt booster pump. The PBT polyester melt is extruded and then air-cooled and shaped, then bundled and oiled, and wound to form PBT-POY fiber. S3. PBT-POY Fiber Texturing: The PBT-POY fibers obtained in step S2 are sequentially processed through a primary roller, a primary hot box deformation, a cooling plate, a false twister for twisting and untwisting, a secondary roller, a secondary hot box setting, a mesh nozzle to increase the mesh density, and a tertiary roller to obtain PBT-DTY matte fiber filaments. The draw ratio between the secondary and primary rollers is 1.16~1.

18. In the primary hot box deformation, a specific hot box is divided into a front hot zone and a rear hot zone. The front section of the hot zone occupies 1 / 4 ± 1 / 8 of the total specific hot zone, and the rear section occupies 3 / 4 ± 1 / 8 of the total specific hot zone. The set temperature of the front section is 280~300℃, and the set temperature of the rear section is 220~240℃. At the same time, nitrogen is introduced into the specific hot zone during one hot zone deformation. In the front section, the nitrogen temperature is 30~40℃ lower than the set temperature of the front section, and in the rear section, the nitrogen temperature is 10~20℃ lower than the set temperature of the rear section. The texturing preparation device used in the PBT-DTY matte elastic memory fiber preparation method includes a specific heating box, which includes a cylindrical box (1). The bottom of the box (1) is provided with a first heating plate corresponding to the front section of the heating zone, and the bottom of the box (1) is provided with a second heating plate (12) corresponding to the rear section of the heating zone. Several guide rails (2) are provided in the middle and lower part of the box (1). A guide device (3) is provided at each end of the box (1). The guide device (3) at the front end guides the PBT-POY fiber into each of the guide rails (2). A main nitrogen pipe (4) is provided on each of the two side walls of the box (1) corresponding to the front end of the front section of the heating zone, and an auxiliary nitrogen pipe (5) is provided on the top of the box (1) corresponding to the front end of the rear section of the heating zone. The auxiliary nitrogen pipe (5) has several rotating fan blades (6) for guiding nitrogen gas through the bottom of the top wall of the box (1). The inner walls of the box (1) are symmetrically provided with a first upper guide plate (13) and a first lower guide plate (14) above and below the front hot zone. The outlet of the main nitrogen pipe (4) is located between the first upper guide plate (13) and the first lower guide plate (14). The inner walls of the box (1) are symmetrically provided with a second upper guide plate (15) and a second lower guide plate (16) above and below the rear hot zone. The connection between the second upper guide plate (15) and the second lower guide plate (16) and the first upper guide plate (13) and the first lower guide plate (14) is a nitrogen mixing section. The rotating fan blades (6) are located in the nitrogen mixing section.

2. The method for preparing PBT-DTY matte elastic memory fiber filaments according to claim 1, characterized in that, In step S1, the catalyst is tetrabutyl titanate, the esterification reaction is carried out under negative pressure, the stirring speed is 100~150 rpm, and the stirring time is 30~60 min.

3. The method for preparing PBT-DTY matte elastic memory fiber filaments according to claim 1, characterized in that, In step S2, the melt booster pump delivers at a pressure of 1-5 MPa, a delivery temperature of 320-340°C, and an extrusion temperature of 280-320°C.

4. The method for preparing PBT-DTY matte elastic memory fiber filaments according to claim 1, characterized in that, In step S3, the nitrogen pressure is 0.005-0.2 bar, and the set temperature for the secondary heating chamber is 50-100℃.

5. The method for preparing PBT-DTY matte elastic memory fiber filaments according to claim 1, characterized in that, A hollow fixed rod (51) is provided below the auxiliary nitrogen pipe (5) located inside the housing (1). A hollow rotating rod (52) is rotatably connected to the bottom of the hollow fixed rod (51). Several through holes (53) are provided in the middle of the hollow rotating rod (52). The through holes (53) are connected to the inside of the hollow fixed rod (51). A hollow turntable (54) is provided at the rear end of the hollow rotating rod (52). The rotating fan blades (6) are evenly spaced on the side wall of the hollow turntable (54). The hollow turntable (54) is connected to the inside of the rotating fan blades (6). An air outlet (61) is provided at the end of the rotating fan blades (6) to allow the nitrogen inside the auxiliary nitrogen pipe (5) to pass sequentially through the inside of the hollow fixed rod (51), the through holes (53), the inside of the hollow rotating rod (52), the inside of the hollow turntable (54), and the rotating fan blades (6). The fan blade (6) is ejected from the air outlet (61) inside. A connecting rod (62) is provided at the center of the rear side of the hollow turntable (54). The end of the connecting rod (62) is provided with a first bevel tooth (63). A drive motor (7) for driving the hollow turntable (54) is provided at the rear of the auxiliary nitrogen pipe (5) on the top of the box (1). The output end of the drive motor (7) is provided with a drive rod (71) that penetrates the top of the box (1). The bottom of the drive rod (71) is provided with a second bevel tooth (72). The second bevel tooth (72) meshes with the first bevel tooth (63) and rotates. A return pipe (17) is provided on the upper part of the rear side wall of the box (1). A heater (8) is provided in the middle of both the main nitrogen pipe (4) and the auxiliary nitrogen pipe (5). The return pipe (17) is connected to the heater (8) on the auxiliary nitrogen pipe (5).

6. The method for preparing PBT-DTY matte elastic memory fiber filaments according to claim 5, characterized in that, The hollow rotating rod (52) has a rotating ring (55) on its front side, and the hollow fixed rod (51) has a rotating groove (56) on its bottom front side. The rotating ring (55) is rotatably connected to the rotating groove (56). A limiting block (57) is provided on the bottom front side of the hollow fixed rod (51) above the rotating groove (56). The bottom of the limiting block (57) extends into the rotating groove (56) to prevent the rotating ring (55) from coming out.

7. The method for preparing PBT-DTY matte elastic memory fiber filaments according to claim 1, characterized in that, The length of the nitrogen mixing section is 1 / 16 of the length of the box (1).

8. The method for preparing PBT-DTY matte elastic memory fiber filaments according to claim 1, characterized in that, The second upper guide plate (15) has an arc-shaped notch (151) on one side corresponding to the nitrogen mixing section. The guide wire hot rail (2) is V-shaped and there are three guide wire hot rails (2).

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