Preparation method of fine denier FDY slub yarn

Abstract

The invention discloses a preparation method of fine-denier FDY slub yarn, which comprises the following steps: a polyester melt is extruded from a spinneret plate and enters a filter element air duct to be cooled and formed into tows, and a plurality of reducing through holes which penetrate through the filter element air duct along the radial direction and through which cooling air passes are formed in the peripheral side of the filter element air duct; the tows are oiled; the oiled tows are drafted through a drafting roller assembly; and the drafted tows are shaped by a heat shaping roller to form the slub yarn. The technical problems that in the prior art, energy consumption is large, and bamboo joint convex lines are not obvious are solved.

Description

Technical Field

[0001] This invention relates to the field of spinning technology, specifically to a method for preparing fine denier FDY slub yarn. Background Technology

[0002] Existing FDY slub filament technology uses an alternating air pressure cooling method to cool the fibers after the polyester melt is spun. By controlling the alternation between the cooled and uncooled sections, the fibers form a slub-like structure. For example, Chinese invention patent CN119352174B discloses "A polyester drawn slub filament and its preparation method." The cooling air pressure corresponding to area A on the spinneret alternates between 35-42 Pa and 65-70 Pa, with each alternation time interval being 0.25 s; the cooling air pressure corresponding to area B on the spinneret alternates between 20-25 Pa and 55-60 Pa, with each alternation time interval being 0.25 s. By using alternating air pressure, the breaking elongation and boiling water shrinkage rate of the continuous fibers can alternate between large and small periods. After heat dyeing, the fabric will show a situation where one section shrinks tightly and is deeply dyed, while another section shrinks less and is lightly dyed, achieving the effect of fancy differential shrinkage. However, the alternating air pressure cooling method has the following problems: 1) Variable frequency compressed air injection can easily cause excessive local expansion of fibers, resulting in a decrease in the strength of bamboo segments. Imitation hemp-style bamboo filaments require continuous adjustment of the compressed air system, which consumes a lot of energy. In addition, it has strict requirements for the precision of the air pressure control equipment, which also consumes a lot of energy. 2) Because the wind pressure alternation cycle is long, it is impossible to produce millimeter-level fine denier short bamboo-joint fibers; 3) Because fine denier polyester filaments have poor spinnability under fluctuating wind pressure conditions, they are prone to breakage during production. 4) Because the through holes of the air duct are of equal diameter, the cooling air enters the through holes and forms a horizontal airflow, which makes the uniformity of the FDY bamboo strands relatively small, generally less than 0.5%, and the bamboo joint texture is not obvious.

[0003] Therefore, a new technical solution is urgently needed to solve at least one of the above technical problems. Summary of the Invention

[0004] In view of the above shortcomings, the purpose of this invention is to provide a method for preparing fine denier FDY bamboo-joint fibers, which solves the technical problems of high energy consumption, limited variety in bamboo-joint style, and indistinct bamboo-joint texture in existing technologies.

[0005] To achieve the above-mentioned technical objectives and meet the above-mentioned technical requirements, the technical solution adopted by the present invention is as follows: A method for preparing fine denier FDY bamboo-joint fibers, characterized by comprising the following steps: Polyester melt is extruded from the spinneret and enters the filter element air duct for cooling and forming into filament bundles. The outer periphery of the filter element air duct is provided with multiple variable diameter through holes that pass through it radially to allow cooling air to pass through. The filament bundle is oiled; After being oiled, the filament bundle is drawn through the drawing roller assembly; The drawn filament bundles are shaped into bamboo-joint filaments by heat-setting rollers.

[0006] As a preferred technical solution, the variable diameter through hole is trumpet-shaped, and the larger diameter end of the variable diameter through hole is located on the inner circumference of the filter element air duct.

[0007] As a preferred technical solution, the expansion angle of the variable diameter through hole is 10°-15°.

[0008] As a preferred technical solution, the drawing assembly includes a first drawing roller and a second drawing roller, the first drawing roller and the second drawing roller are respectively fitted with a first roller shell and a second roller shell, and a non-smooth area is provided on the outer peripheral side of the end of the first roller shell.

[0009] As a preferred technical solution, the non-smooth area includes multiple concentric pits, with adjacent pits staggered in the axial direction.

[0010] As a preferred technical solution, the bottom surface of the recess is arc-shaped.

[0011] As a preferred technical solution, the maximum depth of the pit is 3-5mm.

[0012] As a preferred technical solution, the wind speed of the cooling air is 0.3m / s-2.5m / s.

[0013] As a preferred technical solution, the filament bundle is oiled through an oil nozzle and an oil pump. The oil pump has a gear, and a plurality of first gear teeth are provided on the outer periphery of the gear. A second gear tooth is provided between two adjacent first gear teeth. The diameter of the tip circle of the first gear tooth is larger than the diameter of the tip circle of the second gear tooth.

[0014] As a preferred technical solution, the filament bundle is shaped into bamboo-like filaments by a heat-setting roller and then wound into a winding machine.

[0015] Compared with traditional technical solutions, the beneficial effects of the present invention are: 1) Cooling air enters the variable diameter through-hole, which changes the cooling air from a horizontal flow to a turbulent flow. The purpose of the turbulent flow is to create turbulent cooling when the filaments extruded from the spinneret pass through the filter core air duct. Turbulent cooling causes the filaments to sway in the turbulent air, making the melt unstable from extrusion from the spinneret orifice to cooling. The originally smooth, straight filaments with uniform axial thickness become uneven in thickness, forming a shape similar to "candied hawthorn". The change in thickness is an important step in the formation of fine denier bamboo joint filaments. Therefore, it is not necessary to change the air pressure, and problems such as filament breakage, excessive local fluffing, and poor bamboo joint strength will not occur. It is suitable for the preparation of fine denier FDY bamboo joint filaments, reducing energy consumption while making the bamboo joint texture more obvious. 2) The horn-shaped variable diameter through-hole structure is simple. The small diameter end of the horn shape serves as the air inlet, and the large diameter end of the horn shape serves as the air outlet, resulting in good turbulence. 3) If the expansion angle of the variable diameter through hole is less than 10°, the turbulence effect is not obvious. If the expansion angle of the variable diameter through hole is greater than 15°, the turbulence effect of the cooling air will also be reduced. 4) Set up non-smooth areas to disrupt the position of the drawing point. The position of the drawing point is used as the contact friction point. The pit and the filament bundle do not contact each other, which eventually forms uneven drawing. The filament bundle is stretched into long filaments of uneven thickness, and finally forms bamboo joint filaments with obvious structural characteristics. 5) The gears of the oil pump can provide different oiling speed and frequency variations. Different combinations of gear tip circle diameters result in different oil coating thicknesses on the filament bundle. The different oil coating thicknesses lead to different friction coefficients between the filament bundle and the filament path, which in turn leads to different tensions on the filament bundle running on the filament path, resulting in microscopic fluctuations. This further affects the uniformity of subsequent stretching, providing the condition of uneven tension before drawing for the formation of bamboo-like filaments. Stretching under uneven tension can further achieve the result of uneven stretching of the filament bundle, thus enabling the filament bundle to form bamboo-like filaments. Attached Figure Description

[0016] Figure 1 This is a structural diagram of a filter cartridge air duct in existing technology; Figure 2 This is a structural diagram of a gear in the prior art; Figure 3 This is a structural diagram of an oil pump provided in one embodiment of the present invention. Figure 4 This is a line graph showing the uniformity of fine denier FDY bamboo filaments during the cooling process through through-holes of equal diameter, as described in existing technology. Figure 5 This is a line graph showing the uniformity of fine denier FDY bamboo-joint filaments during the cooling process through a variable diameter through-hole, according to an embodiment of the present invention. Figure 6 This is a flowchart of a preparation method provided in one embodiment of the present invention; Figure 7 This is a structural diagram of a spinning assembly provided in one embodiment of the present invention; Figure 8 This is a cross-sectional view of a filter cartridge air duct provided in one embodiment of the present invention; Figure 9 This is a structural diagram of a filter cartridge air duct provided in one embodiment of the present invention; Figure 10 This is a structural diagram of a variable diameter through hole provided in one embodiment of the present invention; Figure 11 This is a schematic diagram of a cooling air cooling filament bundle provided in an embodiment of the present invention; Figure 12 This is a structural diagram of the first roller shell provided in one embodiment of the present invention; Figure 13 This is a structural diagram of the first roller shell provided in a preferred embodiment of the present invention; Figure 14 This is a structural diagram of the first roller shell provided in another preferred embodiment of the present invention; Figure 15 This is a structural diagram of a drawing assembly provided in one embodiment of the present invention; Figure 16 This is a detailed view of the first roller shell provided in one embodiment of the present invention; Figure 17 This is a texture image of the fine denier FDY bamboo-joint fibers prepared in Example 1; Figure 18 This is a texture image of the fine denier FDY bamboo-joint fibers prepared in Example 2; Figure 19 This is a texture image of the fine denier FDY bamboo-joint filaments prepared in Example 3.

[0017] exist Figures 1-19 In the middle: 1. Spinneret; 2. Spinning air box; 3. Filter air duct; 301. Variable diameter through hole; 4. Oil nozzle; 5. Oil pump; 501. First gear; 5011. First tooth; 5012. Second tooth; 502. Second gear; 5021. First gear tooth; 5022. Second gear tooth; 503. Oil inlet; 504. Oil outlet; 6. First drafting roller; 601. First roller shell; 6011. Dent; 7. Second drafting roller; 701. Second roller shell; 8. Heat setting roller; 9. Winding machine; 10. Yarn bundle. Detailed Implementation

[0018] The invention will now be further described with reference to the accompanying drawings.

[0019] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "top", "bottom", "left", "right", "front", "rear", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0020] Please refer to Figures 1-19 An embodiment of the present invention provides a method for preparing fine denier FDY bamboo-joint fibers, comprising the following steps: S1. Polyester melt is extruded from spinneret 1 into filter element air duct 3 for cooling and forming into filament bundle 10. The outer periphery of filter element air duct 3 is provided with multiple variable diameter through holes 301 that pass through it radially for cooling air to pass through. S2. Apply oil to the filament bundle 10; S3. The oiled filament bundle 10 is drawn through the drawing roller assembly; S4. The drawn filament bundle 10 is shaped into bamboo-joint filaments by the heat-setting roller 8; S5. Bamboo-joint filaments enter the winding machine 9 for winding.

[0021] Cooling air enters the variable diameter through-hole 301, which changes the cooling air from a horizontal flow to a turbulent flow. The purpose of the turbulent flow is to create disordered cooling when the filament bundle 10 extruded from the spinneret 1 passes through the filter core air duct 3. The disordered cooling causes the filament bundle 10 to sway in the turbulent air, making the melt unstable from extrusion from the spinneret 1 hole to cooling. The originally smooth, straight filament bundle 10 with uniform axial thickness becomes uneven in thickness, forming a shape similar to "candied hawthorn". The change in thickness is an important step in the formation of fine denier bamboo joint filaments. Therefore, it is not necessary to change the air pressure, and problems such as filament breakage, excessive local fluffing, and poor bamboo joint strength will not occur. It is suitable for the preparation of fine denier FDY bamboo joint filaments, reducing energy consumption while making the bamboo joint filament texture more obvious.

[0022] like Figures 1-19As shown, the variable diameter through hole 301 is trumpet-shaped. The larger diameter end of the variable diameter through hole 301 is located on the inner circumference of the filter element air duct 3. The trumpet-shaped variable diameter through hole 301 has a simple structure. The smaller diameter end of the trumpet shape serves as the air inlet, and the larger diameter end serves as the air outlet. The resulting turbulence effect is good. Since the through hole of the air duct is of equal diameter, the cooling air forms a horizontal flow after entering the through hole, which makes the cv% (strip uniformity) of the fine denier FDY bamboo filaments relatively small, generally less than 0.5%. The fine denier FDY bamboo filaments prepared by the trumpet-shaped variable diameter through hole 301 have a cv% of more than 5.0% and have significant bamboo joint texture characteristics.

[0023] like Figures 1-19 As shown, the expansion angle of the variable diameter through hole 301 is 10°-15°. If the expansion angle of the variable diameter through hole 301 is less than 10°, the turbulence effect is not obvious. If the expansion angle of the variable diameter through hole 301 is greater than 15°, the turbulence effect of the cooling air will also be reduced.

[0024] like Figures 1-19 As shown, specifically, the spinning assembly includes a spinneret 1, a spinning air box 2, an oil nozzle 4, an oil pump, a drafting assembly, a heat-setting roller 8, and a winding machine 9. A filter cartridge air duct 3 is installed inside the spinning air box 2. The drafting assembly includes a first drafting roller 6 and a second drafting roller 7. The first drafting roller 6 and the second drafting roller 7 are respectively fitted with a first roller shell 601 and a second roller shell 701. A non-smooth area is provided on the outer periphery of the end of the first roller shell 601. Both the first drafting roller 6 and the second drafting roller 7 have heating functions. The filament bundle 10 wraps around the first roller shell 601, then around the second roller shell 701, and then around the first roller shell 601 again, exiting from the end of the first roller shell 601. The purpose is to heat the filament bundle 10 to its glass transition temperature when it exits the end of the first roller shell 601. A speed difference in drafting is formed between the heat setting roller 8 and the heat setting roller 8. The rotational speed of the heat setting roller 8 is higher than that of the first drafting roller 6 and the second drafting roller 7. Stretch deformation occurs at the end of the second roller shell 701. The point where the stretching begins is called the drafting point of the filament bundle 10. After exiting the drafting point, the filament bundle 10 begins to lengthen, reducing its diameter and increasing its strength. The stability of the drafting point position is crucial for the production of conventional FDY. Therefore, the drafting rollers of conventional FDY have a smooth and uniform surface from the inside out. However, the technical solution of this invention utilizes the filament bundle 10 at the end of the first roller shell 601, setting a non-smooth area to form an uneven drafting point, ultimately creating uneven drafting. This stretches the filament bundle 10 into long filaments of uneven thickness, finally forming bamboo-joint filaments with obvious bamboo-joint texture.

[0025] like Figures 1-19As shown, the non-smooth area includes multiple rings of pits 6011. Two adjacent pits 6011 in the axial direction are staggered. The pits 6011 are set to disrupt the position of the drawing point. The drawing point is located at the contact friction point between the pit 6011 and the filament bundle 10. Different patterns of bamboo-joint filaments can also be prepared by changing the spacing of the same ring of pits 6011 and the maximum diameter of the pits 6011.

[0026] like Figures 1-19 As shown, the bottom surface of the recess 6011 is arc-shaped, the maximum depth of the recess 6011 is 3-5mm, and the shape of the recess 6011 is circular. If the maximum depth of the recess 6011 is less than 3mm, the oil will easily accumulate in the recess 6011 and overflow, which will affect the spinning. If the maximum depth of the recess 6011 is greater than 5mm, the thickness of the first roller shell 601 needs to be increased, which is not conducive to heat conduction and increases the material cost.

[0027] like Figures 1-19 As shown, the wind speed of the cooling air is 0.3m / s-2.5m / s. Within this range, the forming effect of the filament bundle 10 is good, and different wind speeds can produce bamboo-like textures with different granular textures.

[0028] like Figures 1-19 As shown, the filament bundle 10 is oiled via an oil nozzle 4 and an oil pump 5. The oil pump 5 has an oil inlet 503 and an oil outlet 504. The oil pump 5 has a gear 501, and the outer circumference of the gear 501 is provided with a plurality of first gear teeth 5011. A second gear tooth 5012 is provided between two adjacent first gear teeth 5011. The diameter of the tip circle of the first gear teeth 5011 is larger than the diameter of the tip circle of the second gear teeth 5012. In this way, the first gear teeth 5011 and the second gear 502 can... The ability to provide different oiling speeds and frequencies ultimately results in different coating thicknesses of the oil on the filament bundle 10. The different oil thicknesses lead to different coefficients of friction between the filament bundle 10 and the filament path, which in turn leads to different tensions on the filament bundle 10 running on the filament path, resulting in microscopic fluctuations. This further affects the uniformity of subsequent stretching, providing the condition of uneven tension before drawing for the formation of bamboo-like filaments. Stretching under uneven tension can further achieve the result of uneven stretching of the filament bundle 10, thereby enabling the filament bundle 10 to form bamboo-like filaments.

[0029] It is worth noting that the present invention improves the structure of the first gear 501 and the second gear 502, while the other structures of the oil pump 5 remain unchanged and adopt conventional settings. The size of the gears of the oil pump 5 is different, and various combinations of different sizes can be designed to affect the changes in the bamboo joint effect, which will not be elaborated further.

[0030] The spinneret 1 has a conventional circular spinneret hole. The existing spinneret 1 used for coarse denier FDY bamboo joint yarn has irregularly shaped spinneret holes such as cross-shaped or trilobal-shaped holes. Irregularly shaped spinneret holes are difficult to process and have high equipment investment costs. The difference in fiber cross-section deformation after false twisting may lead to a rough feel of bamboo joint segments. It can only be used for coarse denier FDY bamboo joint yarn and cannot be used for fine denier FDY bamboo joint yarn. Example

[0031] The spinning assembly includes a spinneret 1, an oil nozzle 4, an oil pump, a drafting assembly, a heat setting roller 8, and a winding machine 9. The drafting assembly includes a first drafting roller 6 and a second drafting roller 7. The first drafting roller 6 and the second drafting roller 7 are respectively fitted with a first roller shell 601 and a second roller shell 701. The outer periphery of the end of the first roller shell 601 is provided with four concave pits 6011. The bottom surface of the concave pits 6011 is arc-shaped, the edge spacing of the concave pits 6011 is 10mm, the diameter of the concave pits 6011 is 20mm, and the maximum depth of the concave pits 6011 is 5mm.

[0032] The oil pump 5 has gears. The outer circumference of the first gear 501 is provided with a plurality of first gear teeth 5011. A second gear tooth 5012 is provided between two adjacent first gear teeth 5011. The diameter of the tip circle of the first gear tooth 5011 is larger than the diameter of the tip circle of the second gear tooth 5012.

[0033] A method for preparing fine denier FDY bamboo-joint fibers includes the following steps: S1. Polyester melt is extruded from spinneret 1 into filter cartridge duct 3 for cooling and forming into filament bundle 10. The outer periphery of the filter cartridge duct 3 is provided with multiple radially penetrating through holes 301 for cooling air to pass through. The holes 301 are trumpet-shaped and have an expansion angle of 10°. The air velocity of the cooling air is 2.3 m / s. S2. The filament bundle 10 is oiled through the oil nozzle 4 and the oil pump 5; S3. After being oiled, the filament bundle 10 is drawn by the drawing roller assembly, that is, the filament bundle 10 is wrapped around the first roller shell 601, then around the second roller shell 701, then around the first roller shell 601 again, and exits from the end of the first roller shell 601. The temperature of the first drawing roller 6 is 70℃ and the rotation speed is 1000m / min. The temperature of the second drawing roller 7 is 70℃ and the rotation speed is 1000m / min. S4. The drawn filament bundle 10 is shaped into bamboo-joint filaments by the heat setting roller 8. The rotation speed of the heat setting roller 8 is 4000m / min and the temperature is 120℃. S5. Bamboo-joint filaments enter the winding machine 9 for winding.

[0034] The final fine denier FDY bamboo strands have the following specifications: 33 dtex / 12f, bamboo strand length of 5-8 mm, bamboo strand diameter of 0.08-0.1 mm, breaking strength of 4.1 cN, and CV% of 5.1%. It is worth noting that the prepared fine denier FDY bamboo strands will have multiple bamboo strands of different sizes. Therefore, the bamboo strand length and diameter are given as examples within a range. Example

[0035] The spinning assembly includes a spinneret 1, an oil nozzle 4, an oil pump, a drafting assembly, a heat setting roller 8, and a winding machine 9. The drafting assembly includes a first drafting roller 6 and a second drafting roller 7. The first drafting roller 6 and the second drafting roller 7 are respectively fitted with a first roller shell 601 and a second roller shell 701. The outer periphery of the end of the first roller shell 601 is provided with four concave pits 6011. The bottom surface of the concave pits 6011 is arc-shaped, the edge spacing of the concave pits 6011 is 5mm, the diameter of the concave pits 6011 is 10mm, and the maximum depth of the concave pits 6011 is 3mm.

[0036] The oil pump 5 has gears. The outer circumference of the first gear 501 is provided with a plurality of first gear teeth 5011. A second gear tooth 5012 is provided between two adjacent first gear teeth 5011. The diameter of the tip circle of the first gear tooth 5011 is larger than the diameter of the tip circle of the second gear tooth 5012.

[0037] A method for preparing fine denier FDY bamboo-joint fibers includes the following steps: S1. Polyester melt is extruded from spinneret 1 into filter cartridge duct 3 for cooling and forming into filament bundle 10. The outer periphery of the filter cartridge duct 3 is provided with multiple radially penetrating through holes 301 for cooling air to pass through. The holes 301 are trumpet-shaped and have an expansion angle of 12°. The air velocity of the cooling air is 1.5 m / s. S2. The filament bundle 10 is oiled through the oil nozzle 4 and the oil pump 5; S3. After being oiled, the filament bundle 10 is drawn by the drawing roller assembly, that is, the filament bundle 10 is wrapped around the first roller shell 601, then around the second roller shell 701, then around the first roller shell 601, and exits from the end of the first roller shell 601. The temperature of the first drawing roller 6 is 55℃ and the rotation speed is 1400m / min. The temperature of the second drawing roller 7 is 55℃ and the rotation speed is 1400m / min. S4. The drawn filament bundle 10 is shaped into bamboo-joint filaments by the heat setting roller 8. The rotation speed of the heat setting roller 8 is 3800m / min and the temperature is 110℃. S5. Bamboo-joint filaments enter the winding machine 9 for winding.

[0038] The final fine denier FDY bamboo fiber has the following specifications: 22 dtex / 12f, bamboo node length of 3-5 mm, bamboo node diameter of 0.05-0.08 mm, breaking strength of 3.9 cN, and CV% of 4.8%. Example

[0039] The spinning assembly includes a spinneret 1, an oil nozzle 4, an oil pump, a drafting assembly, a heat setting roller 8, and a winding machine 9. The drafting assembly includes a first drafting roller 6 and a second drafting roller 7. The first drafting roller 6 and the second drafting roller 7 are respectively fitted with a first roller shell 601 and a second roller shell 701. The outer periphery of the end of the first roller shell 601 is provided with eight concave pits 6011. The bottom surface of the concave pits 6011 is arc-shaped, the edge spacing of the concave pits 6011 is 3mm, the diameter of the concave pits 6011 is 5mm, and the maximum depth of the concave pits 6011 is 4mm.

[0040] The oil pump 5 has gears. The outer circumference of the first gear 501 is provided with a plurality of first gear teeth 5011. A second gear tooth 5012 is provided between two adjacent first gear teeth 5011. The diameter of the tip circle of the first gear tooth 5011 is larger than the diameter of the tip circle of the second gear tooth 5012.

[0041] A method for preparing fine denier FDY bamboo-joint fibers includes the following steps: S1. Polyester melt is extruded from spinneret 1 into filter cartridge duct 3 for cooling and forming into filament bundle 10. The outer periphery of the filter cartridge duct 3 is provided with multiple radially penetrating through holes 301 for cooling air to pass through. The holes 301 are trumpet-shaped and have an expansion angle of 15°. The air velocity of the cooling air is 0.6 m / s. S2. The filament bundle 10 is oiled through the oil nozzle 4 and the oil pump 5; S3. After being oiled, the filament bundle 10 is drawn by the drawing roller assembly, that is, the filament bundle 10 is wrapped around the first roller shell 601, then around the second roller shell 701, then around the first roller shell 601, and exits from the end of the first roller shell 601. The temperature of the first drawing roller 6 is 50℃ and the rotation speed is 1600m / min. The temperature of the second drawing roller 7 is 50℃ and the rotation speed is 1600m / min. S4. The drawn filament bundle 10 is shaped into bamboo-joint filaments by the heat setting roller 8. The rotation speed of the heat setting roller 8 is 3500m / min and the temperature is 105℃. S5. Bamboo-joint filaments enter the winding machine 9 for winding.

[0042] The final fine denier FDY bamboo fiber has the following specifications: 22dtex / 24f, bamboo node length of 1-2mm, bamboo node diameter of 0.03-0.05mm, breaking strength of 3.7cN, and CV% of 4.2%.

[0043] The fine denier FDY bamboo fibers prepared in Examples 1-3 are delicate and have a soft luster, exhibiting a silk-like drape and hazy beauty, suitable for modern minimalist, light luxury, or forest style. In terms of touch, they are soft and skin-friendly, with a delicate touch close to natural fibers, suitable for wearing next to the skin, and can be used to make high-end women's clothing (such as dresses, shirts), underwear, lightweight bedding, scarves, and bio-based smart textiles.

[0044] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values ​​less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are explicitly described in this specification in a similar manner.

[0045] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0046] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0047] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0048] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A method for preparing fine denier FDY bamboo-joint fibers, characterized in that, include: Polyester melt is extruded from the spinneret and enters the filter element air duct for cooling and forming into filament bundles. The outer periphery of the filter element air duct is provided with multiple variable diameter through holes that pass through it radially to allow cooling air to pass through. The filament bundle is oiled; After being oiled, the filament bundle is drawn through the drawing roller assembly; The drawn filament bundles are shaped into bamboo-joint filaments by heat-setting rollers.

2. The method for preparing fine denier FDY bamboo-joint fibers according to claim 1, characterized in that, The variable diameter through hole is trumpet-shaped, and the larger diameter end of the variable diameter through hole is located on the inner circumference of the filter element air duct.

3. The method for preparing fine denier FDY bamboo-joint fibers according to claim 1, characterized in that, The expansion angle of the variable diameter through hole is 10°-15°.

4. The method for preparing fine denier FDY bamboo-joint fibers according to claim 1, characterized in that, The drawing assembly includes a first drawing roller and a second drawing roller. The first drawing roller and the second drawing roller are respectively fitted with a first roller shell and a second roller shell. A non-smooth area is provided on the outer peripheral side of the end of the first roller shell.

5. The method for preparing fine denier FDY bamboo-joint fibers according to claim 4, characterized in that, The non-smooth region includes multiple concentric rings of pits, with unequal spacing between pits in adjacent rings.

6. The method for preparing fine denier FDY bamboo-joint fibers according to claim 1, characterized in that, The bottom surface of the pit is arc-shaped.

7. The method for preparing fine denier FDY bamboo-joint fibers according to claim 1, characterized in that, The maximum depth of the pit is 3-5 mm.

8. The method for preparing fine denier FDY bamboo-joint fibers according to claim 1, characterized in that, The cooling air velocity is 0.3m / s-2.5m / s.

9. The method for preparing fine denier FDY bamboo-joint fibers according to claim 1, characterized in that, The filament bundle is oiled through an oil nozzle and an oil pump. The oil pump has a gear, and a plurality of first gear teeth are provided on the outer circumference of the gear. A second gear tooth is provided between two adjacent first gear teeth. The diameter of the tip circle of the first gear tooth is larger than the diameter of the tip circle of the second gear tooth.

10. The method for preparing fine denier FDY bamboo-joint fibers according to claim 1, characterized in that, The filament bundle is shaped into bamboo-like filaments by a heat-setting roller and then enters a winding machine for winding.

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