Coarse denier, few-hole, super-heavy mesh dty fiber and method of making same

Abstract

The application discloses a coarse denier few-hole super heavy network DTY fiber and a preparation method thereof, and relates to the technical field of spinning. The preparation method of the coarse denier few-hole super heavy network DTY fiber comprises the following steps: step S10, preparing a spinning melt, wherein polydimethylsiloxane is added in the spinning melt; step S20, preparing a pre-oriented yarn; the spinning melt is extruded through a spinneret, and after being cooled and solidified, the pre-oriented yarn is obtained through oiling and winding; the spinneret is provided with circular spinning holes and rectangular spinning holes, and the number of the rectangular spinning holes accounts for 15% to 25% of the total number of the spinning holes; and step S30, performing drafting and false twisting processing on the pre-oriented yarn to obtain the coarse denier few-hole super heavy network DTY fiber. The coarse denier few-hole super heavy network DTY fiber and the preparation method thereof provided in the specification can enable monofilaments to closely hold together, enhance network firmness, and reduce the swelling effect to better maintain the shape.

Description

Technical Field

[0001] This specification relates to the field of spinning technology, and in particular to a coarse denier, low-pore, ultra-heavy web DTY fiber and its preparation method. Background Technology

[0002] DTY (Draw Textured Yarn) is a type of textured yarn, also known as elastic yarn. It is made from polyester chips (PET) as raw material, which is spun into pre-oriented polyester yarn (POY) at high speed, and then drawn and false-twisted. DTY is characterized by a short process, high efficiency, and good quality, and is commonly used in the production of decorative fabrics, clothing fabrics, and linings.

[0003] Coarse denier, low-pore DTY generally uses coarse denier round-hole yarn with no more than 48 holes. Main varieties include 150 / 48, 150 / 36, and 200 / 48. It is widely used in downstream water-jet and air-jet woven products. Because of its strong network structure, it can be used directly on the machine without sizing. The POY cross-section used in coarse denier, low-pore DTY is mainly circular. Due to its low yarn count, high monofilament fineness, and small specific surface area, there are large gaps between the monofilaments, making it difficult for airflow to wind and bind the monofilaments together. Even with various nozzle types and air pressures, ideal firmness cannot be achieved during texturing.

[0004] Currently, coarse denier, low-pore DTY (dimethyl methacrylate) fabrics suffer from insufficient strength, preventing air-jet looms from increasing speed and significantly reducing product profitability. Texturing currently uses large-diameter nozzles and high air pressure to increase network strength; however, not only does it fail to significantly improve network strength, but the high-speed airflow also breaks monofilaments, causing fuzz, and increases air consumption, leading to higher production costs. Summary of the Invention

[0005] The inventors discovered that flat yarns with rectangular cross-sections exhibit significantly better cohesion between filaments than round yarns with circular cross-sections. Flat yarns can greatly improve the fabric's resistance to snagging and cutting. Flat yarns are produced using shaped spinnerets. Because their filament cross-sections are approximately rectangular, they have a larger specific surface area compared to circular cross-sections, increasing the light reflection area and making the fabric more lustrous.

[0006] The production process of flat filaments is basically the same as that of ordinary round filaments. However, due to the shear stress experienced by the melt in the spinneret, it stores a large amount of elastic potential energy. Elastic recovery occurs after extrusion, and the difference in normal stress during melt shear flow causes an expansion zone larger than the die diameter to appear after the melt exits the die. The presence of this expansion zone makes it difficult for the rectangular cross-section to maintain its shape. Ensuring that the melt retains its shape after exiting the die is crucial to the successful production of flat filaments.

[0007] In view of the shortcomings of the prior art, one object of this specification is to provide a coarse denier, low-pore, ultra-heavy web DTY fiber and its preparation method, which enables the monofilaments to be tightly bound together, enhances the network strength, and reduces the swelling effect to better maintain shape.

[0008] To achieve the above objectives, this application provides a method for preparing coarse denier, low-pore, ultra-heavy mesh DTY fiber, comprising the following steps: Step S10: Prepare a spinning melt, wherein polydimethylsiloxane is added to the spinning melt; Step S20: Pre-oriented yarn preparation; the spinning melt is extruded through a spinneret, cooled and solidified, then oiled and wound to obtain the pre-oriented yarn; the spinneret is provided with circular spinneret holes and rectangular spinneret holes, and the number of rectangular spinneret holes accounts for 15% to 25% of the total number of spinneret holes; Step S30: The pre-oriented yarn is drawn and false-twisted to obtain coarse denier, low-pore, ultra-heavy web DTY fiber.

[0009] In a preferred embodiment, step S10 includes the following steps: Step S11: Prepare a slurry from terephthalic acid and ethylene glycol; Step S12: Add a catalyst, a stabilizer, and polydimethylsiloxane to the slurry to carry out an esterification reaction to obtain bis(hydroxyethylene) terephthalate; the catalyst is one of antimony trioxide, antimony glycolate, or antimony acetate, and the stabilizer is one of triphenyl phosphate, trimethyl phosphate, or trimethyl phosphite. Step S13: The bis(hydroxyethylene) terephthalate is subjected to polycondensation reactions in a near-vacuum stage and a high-vacuum stage in sequence to obtain the spinning melt.

[0010] In a preferred embodiment, the molar ratio of terephthalic acid to ethylene glycol is 1:1.2~2.0; the degree of polymerization of the polydimethylsiloxane is 5~12, the melting point is -40℃~-30℃, the dynamic viscosity is ≤1Pa·s, the mass of the polydimethylsiloxane is 0.2%~0.5% of the mass of the slurry; the amount of catalyst added is 0.01%~0.05% of the weight of the terephthalic acid; and the amount of stabilizer added is 0.01%~0.05% of the weight of the terephthalic acid.

[0011] In a preferred embodiment, the esterification reaction is carried out in a nitrogen pressurized atmosphere, with a pressure of atmospheric pressure to 0.3 MPa; the temperature of the esterification reaction is 250°C to 260°C; in the near-vacuum stage, the reaction pressure is steadily reduced from atmospheric pressure to below 500 Pa absolute pressure, the reaction temperature is controlled at 260°C to 270°C, and the reaction time is 30 min to 50 min; in the high-vacuum stage, the reaction pressure is controlled at below 100 Pa absolute pressure, the reaction temperature is controlled at 275°C to 285°C, and the reaction time is 50 min to 90 min.

[0012] In a preferred embodiment, in step S20, the area of ​​the circular spinneret is equal to the area of ​​the rectangular spinneret; the outlet surface of the spinneret plate is provided with four rings of spinnerets, which are arranged from the inside out as a circular spinneret, a rectangular spinneret, a circular spinneret, and a circular spinneret; each ring of spinnerets is evenly spaced in the circumferential direction, and the center line connecting the centers of each ring of spinnerets forms four concentric circles.

[0013] In a preferred embodiment, the aspect ratio of the rectangular spinneret is 8 to 12, and the long side of the rectangular spinneret is parallel to the radial direction; the diameter of the circular spinneret is 0.26 mm to 0.30 mm; and the spacing between adjacent spinnerets is 2.2 mm or more.

[0014] In a preferred embodiment, the swell ratio of the spinning melt extruded from the spinneret is 1.08 to 1.25.

[0015] In a preferred embodiment, the pre-oriented yarn prepared in step S20 has a fineness of 260 dtex to 350 dtex, a linear density deviation of ≤0.5%, a breaking strength of ≥2.58 cn / dtex, a breaking strength coefficient of variation of ≤4%, a breaking elongation of 135±3%, a breaking elongation coefficient of variation of ≤8%, a yarn unevenness coefficient of variation of ≤2%, and a flatness of ≥3.

[0016] This application also provides a coarse denier, low-pore, ultra-heavy mesh DTY fiber, which is prepared by the preparation method described in any of the above embodiments.

[0017] In a preferred embodiment, the linear density of the coarse denier, low-pore, ultra-heavy DTY fiber is 167 dtex to 200 dtex, with a linear density deviation of ≤1%; the breaking strength is ≥3.9 cn / dtex, with a breaking strength coefficient of variation of ≤2%; and the breaking elongation is ≥18%, with a breaking elongation coefficient of variation of ≤8%. Beneficial effects

[0018] The method for preparing coarse denier, low-pore, ultra-heavy web DTY fiber provided in this embodiment involves redesigning the spinneret and introducing a certain proportion (15%~25%) of rectangular spinneret holes to increase the specific surface area of ​​the monofilaments, increase the contact area between the monofilaments, enable the monofilaments to tightly bind together, enhance the web strength, and provide a solution to the problem of shape retention difficulties caused by extrusion expansion of rectangular cross-sections. This produces POY (pre-oriented yarn) that meets the requirements of ultra-heavy webs. After stretching and deformation and web bonding, the POY is used to obtain ultra-heavy web DTY.

[0019] This invention incorporates polydimethylsiloxane (CMS), with the chemical formula (CH3)3SiO2((CH3)2SiO)nSi(CH3)3, into the polyester melt to enhance the lubricity between the melt and the spinneret orifice wall during extrusion. This effectively reduces the pressure drop of the melt within the spinneret orifice, thereby lowering the melt shear stress and normal stress difference. The melt relaxes more quickly within the spinneret orifice, effectively mitigating extrusion swell and reducing the extrusion swell ratio, resulting in a product with excellent shape retention. Furthermore, PMS does not damage the structure of the polyester fiber, preserving its excellent properties. Its refractive index is 1.402~1.403, lower than the refractive index of polyester (1.52~1.54). It not only does not affect the transparency of the product but also increases the brightness of the polyester fiber.

[0020] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.

[0021] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0022] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart illustrating the steps of a method for preparing coarse denier, low-pore, ultra-heavy mesh DTY fiber provided in this embodiment. Figure 2 This is a top view of a spinneret provided in this embodiment; Figure 3 This is a bottom view of a spinneret provided in this embodiment; Figure 4 This is a partial cross-sectional structural diagram of a spinneret provided in this embodiment.

[0025] Explanation of reference numerals in the attached figures: 1. Spinneret; 2. Spinneret orifice; 21. Circular spinneret orifice; 22. Rectangular spinneret orifice; 3. Inlet. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0027] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] Please see Figure 1 This application provides a method for preparing coarse denier, low-pore, ultra-heavyweight DTY fiber, comprising the following steps: Step S10: Prepare a spinning melt, wherein polydimethylsiloxane is added to the spinning melt; Step S20: Pre-oriented yarn is prepared; the spinning melt is extruded through spinneret 1, cooled and solidified, then oiled and wound to obtain the pre-oriented yarn; the spinneret 1 is provided with circular spinneret holes 21 and rectangular spinneret holes 22, and the number of rectangular spinneret holes 22 accounts for 15% to 25% of the total number of spinneret holes 2; Step S30: The pre-oriented yarn is drawn and false-twisted to obtain coarse denier, low-pore, ultra-heavy web DTY fiber.

[0030] The method for preparing coarse denier, low-pore, ultra-heavy web DTY fiber provided in this embodiment involves redesigning the spinneret 1 and introducing a certain proportion (15%~25%) of rectangular spinneret holes 22 to increase the specific surface area of ​​the monofilaments, increase the contact area between the monofilaments, enable the monofilaments to tightly bind together, enhance the web strength, and provide a solution to the problem of shape retention difficulties caused by extrusion expansion of rectangular cross-sections. This produces POY (pre-oriented yarn) that meets the requirements of ultra-heavy webs. After stretching and deformation and web bonding, the POY is used to obtain ultra-heavy web DTY.

[0031] The proportion of rectangular spinnerets 22 is 15% to 25%. This is because if the proportion of rectangular spinnerets 22 is less than 15%, it cannot meet the requirements of heavy-duty mesh, and the final DTY mesh will not have sufficient strength. If the proportion of rectangular spinnerets 22 is greater than 25%, it will lead to a decrease in POY strength and elongation, and consequently, a decrease in DTY strength and elongation. Furthermore, since rectangular spinnerets 22 are irregularly shaped holes, their shearing rates differ significantly from round holes, and poor process control can easily result in core-sheathed wires, increasing processing difficulty. A number of rectangular spinnerets 22 accounting for 15% to 25% of the total number of spinnerets 2 can meet the requirements of heavy-duty mesh. For example, the number of rectangular spinnerets 22 can be 8, 10, 12, etc., corresponding to a total number of spinnerets 2 on the spinneret 1 of 48, 60, 72, etc.

[0032] This invention incorporates polydimethylsiloxane (CMS), with the chemical formula (CH3)3SiO2((CH3)2SiO)nSi(CH3)3, into the polyester melt to enhance the lubricity between the melt and the spinneret orifice 2 wall during extrusion. This effectively reduces the pressure drop of the melt within the spinneret orifice 2, thereby lowering the melt shear stress and normal stress difference. The melt relaxes more quickly within the spinneret orifice 2, effectively mitigating extrusion swell and reducing the extrusion swell ratio, resulting in a product with excellent shape retention. Furthermore, PMS does not damage the structure of the polyester fiber, preserving its excellent properties. Its refractive index is 1.402~1.403, lower than the refractive index of polyester (1.52~1.54). It not only does not affect the transparency of the product but also increases the brightness of the polyester fiber.

[0033] Specifically, the methyl group (-CH3) of polydimethylsiloxane is a nonpolar group, compatible with nonpolar polyester melts, while its siloxy group (-SiO-) is a polar group, incompatible with polyester melts. Furthermore, the dynamic viscosity of polydimethylsiloxane is much lower than that of the polyester melt. This characteristic allows polydimethylsiloxane to migrate and flow through the polyester melt to the polyester surface, forming an interfacial film effect with the metal surface of the spinneret 2. This interfacial film effectively reduces the frictional force exerted on the melt by the wall of the spinneret 2, thereby reducing the pressure drop, shear stress, and normal stress difference. This reduces the expansion effect of the melt after exiting the spinneret 2, allowing the rectangular spinneret 22 to better maintain its shape.

[0034] In this embodiment, step S10 specifically includes the following steps: Step S11: Prepare a slurry from terephthalic acid and ethylene glycol; Step S12: Add catalyst, stabilizer and polydimethylsiloxane to the slurry to carry out esterification reaction to obtain bis(hydroxyethylene) terephthalate; Step S13: The bis(hydroxyethylene) terephthalate is subjected to polycondensation reactions in a near-vacuum stage and a high-vacuum stage in sequence to obtain the spinning melt.

[0035] In step S11, the molar ratio of terephthalic acid to ethylene glycol is 1:1.2~2.0. In step S12, the catalyst is one of antimony trioxide, antimony glycolate, or antimony acetate. The amount of catalyst added is 0.01%~0.05% of the weight of terephthalic acid. The stabilizer is one of triphenyl phosphate, trimethyl phosphate, or trimethyl phosphite. The amount of stabilizer added is 0.01%~0.05% of the weight of terephthalic acid.

[0036] The degree of polymerization of the polydimethylsiloxane is 5-12, i.e., in (CH3)3SiO2((CH3)2SiO)nSi(CH3)3, the value of n is 5-12. The melting point of the polydimethylsiloxane is -40℃ to -30℃, and the dynamic viscosity is ≤1 Pa·s. The mass of the polydimethylsiloxane is 0.2% to 0.5% of the mass of the slurry.

[0037] Specifically, the esterification reaction in step S12 is carried out under a nitrogen pressurized atmosphere, with a pressure of atmospheric pressure to 0.3 MPa. The temperature of the esterification reaction is 250℃ to 260℃. The esterification reaction is considered to have ended when the amount of water distilled off in the esterification reaction reaches more than 90% of the theoretical value. At this point, the reactant is mainly the oligomer BHET di(hydroxyethylene) terephthalate.

[0038] In step S13, during the near-vacuum stage, the reaction pressure is steadily reduced from atmospheric pressure to below 500 Pa absolute pressure, the reaction temperature is controlled at 260℃~270℃, and the reaction time is 30min~50min. Then, vacuuming continues. During the high-vacuum stage, the reaction pressure is controlled below 100 Pa absolute pressure, the reaction temperature is controlled at 275℃~285℃, and the reaction time is 50min~90min.

[0039] In this embodiment, in step S20, the area of ​​the circular spinneret 21 and the area of ​​the rectangular spinneret 22 are made equal to ensure that the outlet flow rate is the same, the stretching ratio is consistent, and the filament thickness is consistent.

[0040] like Figure 2 and Figure 3 As shown, the spinneret 1 has four rings of spinneret holes 2, arranged from the inside out as a ring of circular spinneret holes 21, a ring of rectangular spinneret holes 22, a ring of circular spinneret holes 21, and a ring of circular spinneret holes 21. Correspondingly, the spinneret 1 has four rings of inlets 3, which can be circular. The spinneret holes 2 are evenly spaced circumferentially, and the center lines of each ring of spinneret holes 2 form four concentric circles. The spacing between adjacent spinneret holes 2 is greater than 2.2 mm to ensure uniform cooling.

[0041] Specifically, the aspect ratio of the rectangular spinneret 22 is 8-12 to ensure that the flatness of the subsequently formed pre-oriented yarn is above 3.0, for example, it can be 3.2. An aspect ratio of 8-12 for the rectangular spinneret 22 is a necessary condition to ensure that the flatness of the finished product is greater than or equal to 3.0. If the aspect ratio is lower than this range, the flatness of the finished product will not reach 3.0, resulting in poor high-weight web performance; if the aspect ratio is higher than this range, the POY core-sheath structure will be severe, and the strength and elongation will be reduced. The long side of the rectangular spinneret 22 is parallel to the radial direction, that is, the rectangular spinneret 22 is set to be evenly distributed inwards towards the center, facilitating contact and bonding with the surrounding monofilaments. The diameter of the circular spinneret 21 is 0.26mm-0.30mm, which is a suitable range for processing 150D to 250D fibers. When the diameter of the circular spinneret 21 is less than 0.26 mm, the shear rate is too high, which can lead to melt rupture and prevent normal spinning in severe cases. When the diameter of the circular spinneret 21 is greater than 0.30 mm, the melt stays in the spinneret for too long, which can lead to melt degradation and yellowing, as well as a drop in component pressure, making it prone to slurry leakage and fiber drift. The diameter of the spinneret 1 is set to 80 mm to 95 mm, and the length-to-diameter ratio at the die end (i.e., the length-to-diameter ratio of the spinneret 1, the ratio of the length to the diameter at the exit of the spinneret 1, i.e....) is... Figure 4 The ratio of the height to the diameter of the spinneret 2 shown is 3.0 to 3.5.

[0042] In step S20, the spinning temperature is maintained at 270℃~300℃, the initial pressure of the spinneret 1 (i.e., the pressure of the spinning melt entering the spinneret) is 8MPa~12MPa, the height of the windless zone is 50mm~70mm, the ring blower pressure is 50Pa~60Pa, the cooling temperature is 20℃~30℃, the oil rack height is 900mm~1200mm, and the spinning speed is 2500m / min~2800m / min.

[0043] Based on the dynamic images of the spinning melt being extruded from the spinneret 2, a three-dimensional simulation dynamic graphic was established, and the ratio of the maximum cross-sectional area of ​​the spinning melt after extrusion from the spinneret 2 to the diameter of the spinneret 2 and the extrusion swell ratio were calculated. Through multiple sets of measurements, the swell ratio of the spinning melt extruded from the spinneret 2 in this embodiment is 1.08~1.25.

[0044] In this embodiment, the fineness of the pre-oriented yarn prepared in step S20 is 260dtex~350dtex, the linear density deviation is ≤0.5%; the breaking strength is ≥2.58cn / dtex, the breaking strength CV (coefficient of variation) is ≤4%; the breaking elongation is 135±3%, the breaking elongation CV is ≤8%; and the yarn unevenness CV is ≤2%.

[0045] In step S30, the specific process route can be: first roller—first heating box—cooling plate—false twister—tension meter—network nozzle—auxiliary roller—second heating box—third roller—black roller—winding and forming. The processing speed is 680m / min~750m / min, the first heating box temperature is 185℃~195℃, the disc assembly is 1-5-1, the nozzle model is P213, the network pressure is 0.28MPa~0.36MPa, and the second heating box temperature is 165℃~175℃. The auxiliary roller's function is to ensure stable tension in the filament, facilitating network formation. Specifically, the pre-oriented yarn (POY finished product) is heated in a hot box and stretched between the first and second rollers. The stretched POY is cooled and solidified by a cooling plate and then false-twisted by a false-twisting machine. After the stretched and false-twisted POY exits the second roller, it is webbed between the second roller and the auxiliary roller through a central web nozzle. The webbed POY then enters the second hot box through the auxiliary roller for heat setting. After heat setting, the POY passes through the third roller and is then wound onto a black roller to obtain the DTY finished product (i.e., coarse denier, low-pore, ultra-heavy web DTY fiber).

[0046] The linear density of the coarse denier, low-pore, ultra-heavy web DTY fiber prepared in step S30 is 167 dtex to 200 dtex, with a linear density deviation of ≤1%; the breaking strength is ≥3.9 cn / dtex, with a breaking strength CV ≤2%; the breaking elongation is ≥18%, with a breaking elongation CV ≤8%.

[0047] Based on the same concept, this embodiment of the invention also provides a coarse denier, low-pore, ultra-heavy mesh DTY fiber, which is prepared by the preparation method provided in any of the above embodiments.

[0048] In this embodiment, the implementation of the coarse denier, low-pore, ultra-heavy mesh DTY fiber corresponds to the implementation of the preparation method. It can solve the technical problems solved by the implementation of the preparation method and achieve the corresponding technical effects of the implementation of the preparation method. The specific details will not be repeated here.

[0049] In a specific application scenario, a spinneret 1 with a specification of 167 / 48 (i.e., a linear density of 167 dBT and 48 holes, meaning that 10,000 meters of DTY weighs 167g and consists of 48 monofilaments) is selected. In the spinneret 1, the number of rectangular spinneret holes 22 accounts for 16.6% of the total number of spinneret holes 2, and the number of circular spinneret holes 21 accounts for 83.4% of the total number of spinneret holes 2. The coarse denier, low-pore, ultra-heavy DTY fiber prepared by the preparation method provided in this application has 110, 111, 110, 112, 111 and 109 network numbers at spindle positions 193, 194, 195, 196, 197 and 198, respectively, and the network strength is high.

[0050] In contrast, a spinneret with a specification of 167 / 48 was selected. The spinneret contained only circular spinneret holes and no rectangular spinneret holes. The same texturing process as above was used. The number of webs at spindle positions 193, 194, 195, 196, 197 and 198 were 101, 103, 101, 102, 99 and 100 respectively, and the web strength was light.

[0051] It can be found that, compared with spinnerets that only have circular spinnerets, introducing a certain proportion of rectangular spinnerets 22 can make the resulting fibers have better network cohesion.

[0052] The criteria for determining the weight of the net as described in this application are as follows: In terms of the number of net points, for example, for 167 / 48 weighted net with P213 nozzle, the number of net points should not be less than 110 per meter; in terms of net strength, weighted net DTY is not easily pulled apart, while ordinary heavy net is relatively easy to pull apart; in terms of water jet or air jet weaving, weighted net DTY can be used directly without sizing and is highly efficient, while ordinary heavy net requires slight sizing before use, which is more complex and has higher processing costs.

[0053] It should be noted that, unless otherwise stated, "multiple" in this specification means two or more.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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 coarse denier, low-pore, ultra-heavyweight DTY fiber, characterized in that, Includes the following steps: step S10: Prepare a spinning melt, wherein polydimethylsiloxane is added to the spinning melt; Step S20: Prepare pre-oriented yarn; The spinning melt is extruded through a spinneret, cooled and solidified, then oiled and wound to obtain the pre-oriented yarn. The spinneret has circular spinneret holes and rectangular spinneret holes, with the number of rectangular spinneret holes accounting for 15% to 25% of the total number of spinneret holes; Step S30: The pre-oriented yarn is drawn and false-twisted to obtain coarse denier, low-pore, ultra-heavy web DTY fiber; the number of pores in the coarse denier, low-pore, ultra-heavy web DTY fiber is no more than 48 pores, and the number of network points is no less than 110 / m; Step S10 includes the following steps: Step S11: Prepare a slurry from terephthalic acid and ethylene glycol; Step S12: Add a catalyst, a stabilizer, and polydimethylsiloxane to the slurry to carry out an esterification reaction to obtain bis(hydroxyethylene) terephthalate; the catalyst is one of antimony trioxide, antimony glycolate, or antimony acetate, and the stabilizer is one of triphenyl phosphate, trimethyl phosphate, or trimethyl phosphite. Step S13: The bis(hydroxyethylene) terephthalate is subjected to polycondensation reactions in a near-vacuum stage and a high-vacuum stage in sequence to obtain the spinning melt.

2. The method for preparing coarse denier, low-pore, ultra-heavy DTY fiber according to claim 1, characterized in that, The molar ratio of terephthalic acid to ethylene glycol is 1:1.2~2.0; the degree of polymerization of the polydimethylsiloxane is 5~12, the melting point is -40℃~-30℃, the dynamic viscosity is ≤1Pa·s, and the mass of the polydimethylsiloxane is 0.2%~0.5% of the mass of the slurry; the amount of catalyst added is 0.01%~0.05% of the weight of the terephthalic acid; and the amount of stabilizer added is 0.01%~0.05% of the weight of the terephthalic acid.

3. The method for preparing coarse denier, low-pore, ultra-heavy DTY fiber according to claim 2, characterized in that, The esterification reaction is carried out in a nitrogen-pressurized atmosphere, with a pressure of atmospheric pressure to 0.3 MPa; the temperature of the esterification reaction is 250℃ to 260℃; in the near-vacuum stage, the reaction pressure is steadily reduced from atmospheric pressure to below 500 Pa absolute pressure, the reaction temperature is controlled at 260℃ to 270℃, and the reaction time is 30 min to 50 min; in the high-vacuum stage, the reaction pressure is controlled at below 100 Pa absolute pressure, the reaction temperature is controlled at 275℃ to 285℃, and the reaction time is 50 min to 90 min.

4. The method for preparing coarse denier, low-pore, ultra-heavy DTY fiber according to claim 1, characterized in that, In step S20, the area of ​​the circular spinneret is equal to the area of ​​the rectangular spinneret; the outlet surface of the spinneret plate is provided with four rings of spinnerets, which are arranged from the inside out as a circular spinneret, a rectangular spinneret, a circular spinneret, and a circular spinneret; each ring of spinnerets is evenly spaced in the circumferential direction, and the center line connecting the rings of spinnerets forms four concentric circles.

5. The method for preparing coarse denier, low-pore, ultra-heavyweight DTY fiber according to claim 4, characterized in that, The aspect ratio of the rectangular spinneret is 8 to 12, and the long side of the rectangular spinneret is parallel to the radial direction; the diameter of the circular spinneret is 0.26 mm to 0.30 mm; the spacing between adjacent spinnerets is more than 2.2 mm.

6. The method for preparing coarse denier, low-pore, ultra-heavy DTY fiber according to claim 5, characterized in that, The swell ratio of the spinning melt extruded from the spinneret is 1.08 to 1.

25.

7. The method for preparing coarse denier, low-pore, ultra-heavyweight DTY fiber according to claim 1, characterized in that, The pre-oriented yarn prepared in step S20 has a fineness of 260 dtex to 350 dtex, a linear density deviation of ≤0.5%, a breaking strength of ≥2.58 cn / dtex, a breaking strength coefficient of variation of ≤4%, a breaking elongation of 135±3%, a breaking elongation coefficient of variation of ≤8%, a yarn unevenness coefficient of variation of ≤2%, and a flatness of ≥3.

8. A coarse denier, low-pore, ultra-heavy web DTY fiber, characterized in that, The coarse denier, low-pore, ultra-heavy mesh DTY fiber is prepared by the preparation method according to any one of claims 1 to 7.

9. The coarse denier, low-pore, ultra-heavy DTY fiber according to claim 8, characterized in that, The linear density of the coarse denier, low-pore, ultra-heavy DTY fiber is 167 dtex to 200 dtex, with a linear density deviation of ≤1%; the breaking strength is ≥3.9 cn / dtex, with a breaking strength coefficient of variation of ≤2%; the breaking elongation is ≥18%, with a breaking elongation coefficient of variation of ≤8%.

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