A segmented fdy / polyester po y combined segmented cotton-like polyester filament and a preparation method thereof

Abstract

The application discloses a kind of bamboo joint FDY / tac POY combination bamboo joint cotton-like dacron filament and its preparation method.The filament is formed by bamboo joint FDY as component A and tac POY as component B and bundle and air interlacing, and conventional section and bamboo joint section are alternately distributed.Preparation is according to bamboo joint section position synchronous signal, and the air supply pressure of interlacing nozzle is segmented locking modulation, so that bamboo joint section forms interlacing enhanced area, and the rest section forms interlacing reference area, and interlacing enhanced area and bamboo joint section are synchronous alignment;Subsequently, limited relaxation heat treatment is carried out, so that component B and component A form certain dry heat shrinkage difference, so that component B forms loop / micro-porous loose structure in interlacing enhanced area, and conventional section is inhibited.The application can realize clear bamboo joint texture, cotton-like loose concentration, improve bundle stability and weavability, reduce opening loose yarn and broken end risk, and is suitable for large-scale production of cotton-like style fabric.

Description

Technical Field

[0001] This invention belongs to the field of textile materials, specifically relating to a slub FDY / polyester POY composite slub cotton-like polyester filament and its preparation method. Background Technology

[0002] Existing polyester slub-like filaments typically achieve this through two pathways: "slub appearance and fluffy / fuzzy feel." One approach utilizes slub filaments (such as slub FDY / DTY) to create variations in thickness along the filament length, achieving a cotton-like stripe and texture. The other approach improves weaving stability and enhances the fluffy feel through heat shrinkage looping and air interlocking (network points) cohesion with low-orientation components (such as POY). For example, Chinese patent CN101748502A discloses an FDY polyester slub filament and its preparation method. By employing uneven stretching in the FDY process and combining it with a pre-network / main network (network density approximately 15±5 nodes / m), the cohesion of the filament bundle is improved, resulting in a snowflake-like slub effect with a relatively simplified process.

[0003] This type of technology can effectively solve the problems of formation and spinnability of single FDY slub filaments, but it is still mainly oriented towards the idea of ​​"single-component FDY slub filaments and uniform network points". The network points are more used for overall cohesion and suppressing filament breakage. It does not involve the mechanism of obtaining a stable cotton-like fluffy structure by bundling slub FDY and polyester POY together and then using "differential shrinkage to form loops". In actual development, when slub FDY and POY are directly bundled and conventionally interlaced before heat relaxation finishing, common problems arise: Different linear density sections (slub sections / conventional sections) exhibit differences in airflow force, tension response, and friction, leading to random or locally excessively dense / sparse interlacing points along the filament length. During post-processing, the shrinkage and looping of POY are amplified by the "locked position" of the interlacing points. If the position of the interlacing points is uncontrollable, loops / micro-bulges will randomly appear along the filament length, easily resulting in uneven fabric hairiness, messy stripes, weakened slub outlines, and even problems such as insufficient slub segment cohesion causing open-end fraying and weaving breakage. To improve these defects, traditional methods often involve increasing the overall interlacing strength or intensifying post-processing, but this can lead to side effects such as a stiffer hand feel, uneven yarn evenness, and increased costs. Therefore, existing technologies still lack a technical solution that can "synchronously segment and interweave according to the position of bamboo segments" in the direction of filament length, so that the interweaving enhancement effect corresponds to the bamboo segment and is stably repeated, thereby taking into account the clear appearance of bamboo segments, the fluffy and concentrated imitation cotton, and good weavability. Summary of the Invention

[0004] The technical objective of this invention is to provide a method for preparing a bamboo-joint FDY / polyester POY composite filament that achieves alignment between the interlacing enhancement zone and the bamboo joint through synchronous segmented interlacing of bamboo joint segments and forms a localized, fluffy, and exposed bamboo joint under differential shrinkage relaxation, so as to balance the stability of the cotton-like appearance and weavability.

[0005] To achieve the above-mentioned technical objectives, the present invention provides the following technical solution.

[0006] In a first aspect, the present invention provides a slub-joint imitation cotton polyester filament, wherein the filament is formed by bundling slub FDY as component A and polyester POY as component B together and interlacing them with air; component A has alternating distribution of conventional segments and slub segments along the filament length direction, the linear density of the slub segments is 1.2 to 3.0 times that of the conventional segments, the length of the slub segments is 5 to 50 mm, and the internode spacing is 50 to 300 mm; During air interlocking, the air supply pressure of the interlocking nozzle is segmented and locked based on the synchronous signal of the bamboo segment position: enhanced interlocking parameters are used in the filament length section corresponding to the bamboo segment, and reference interlocking parameters are used in the other filament length sections, thereby forming an enhanced interlocking zone and a reference interlocking zone along the filament length direction; the enhanced interlocking zone is synchronously aligned with the bamboo segment with an alignment error ≤ ±10mm, the coverage ratio of the enhanced interlocking zone to the bamboo segment is ≥60%, and the density of interlocking points in the enhanced interlocking zone is 1.5 to 4.0 times that of the reference interlocking zone; The mass ratio of component A to component B is 30-70:70-30; after the filament is subjected to relaxation heat treatment at 160-200℃, component B forms a ring / micro-fluffy exposed structure in the interlacing reinforcement zone, and the difference in dry heat shrinkage rate between component B and component A is 6-20%.

[0007] Preferably, the gas supply pressure of the interlocking nozzle corresponding to the enhanced interlocking parameters and the reference interlocking parameters are 0.25-0.60 MPa and 0.10-0.25 MPa, respectively.

[0008] Preferably, the bamboo segment position synchronization signal is obtained by any one or a combination of photoelectric / laser diameter measurement and identification, tension fluctuation feature identification, image recognition, or component A silk supply encoding signal.

[0009] Preferably, the length of the intercalation enhancement zone is 0.8 to 1.5 times the length of the corresponding bamboo segment.

[0010] Preferably, the equivalent overfeed rate of component B in the intercalation enhancement region is higher than that in the intercalation reference region, with a difference of 2-15%.

[0011] As a preferred method, the air interlocking adopts a two-stage interlocking method, including pre-interlocking and main interlocking. Pre-interlocking is used to form a reference interlocking point throughout the entire process, while main interlocking is used to form an enhanced interlocking point in the silk length section corresponding to the bamboo node segment.

[0012] Secondly, the present invention also provides a method for preparing the slub-joint imitation cotton polyester filament described in the first aspect, comprising the following steps: S1, yarn supply and bundling: Supply slub FDY as component A and polyester POY as component B and bundle them together; S2. Synchronous Positioning: Online detection of bamboo segment position or reading of component A silk supply code to obtain bamboo segment position synchronization signal; S3. Segmented locking air interlacing: Based on the synchronization signal, the air supply pressure of the interlacing nozzle is switched segment by segment. Enhanced interlacing parameters are used in the silk length section corresponding to the bamboo joint segment, and reference interlacing parameters are used in the other silk length sections to form an enhanced interlacing area and a reference interlacing area with a synchronous alignment error of ≤±10mm with the bamboo joint segment, a coverage ratio of ≥60%, and an interlacing point density ratio of 1.5~4.0. S4. Relaxation heat treatment: The composite yarn after interlacing is subjected to relaxation heat treatment at 160-200℃, so that component B forms a ring / micro-loose exposed structure in the interlacing reinforcement zone and obtains a dry heat shrinkage rate difference of 6-20%. S5. Winding: The finished filament is obtained by winding.

[0013] Preferably, the online detection in step S2 uses laser diameter measurement or photoelectric detection to identify abrupt changes in the diameter of bamboo segments, and / or uses a tension sensor to identify the tension characteristics of bamboo segments.

[0014] Preferably, step S3 corrects the gas supply pressure amplitude of the interlacing nozzle based on the online counting results of interlacing points, so as to maintain the interlacing point density ratio between the interlacing enhancement zone and the interlacing reference zone at 1.5 to 4.0.

[0015] Preferably, step S4 is restricted relaxation with a relaxation ratio of 1.03 to 1.20, in order to suppress random loop formation in the interlacing reference region and enhance the exposure of loops in the interlacing enhancement region.

[0016] The working mechanism of this invention is as follows: after slub FDY and polyester POY are bundled together, the air supply pressure of the interlacing nozzle is segmented and locked and modulated according to the synchronous signal of the slub segment position during the air interlacing process. This makes the filament length section corresponding to the slub segment form the interlacing reinforcement zone, and the remaining sections form the interlacing reference zone, and makes the reinforcement zone and the slub segment synchronously aligned. Under the subsequent relaxation heat treatment, the differential shrinkage driving force generated by POY relative to FDY is released in an orderly manner near the "anchor point" of the interlacing reinforcement zone, so that POY forms a ring / micro-fluffy exposure in the section corresponding to the slub segment, while the exposure of the regular section is suppressed, realizing the structural construction of "localized ring formation and zoned shaping".

[0017] The beneficial technical effects achieved by this invention are as follows: the synchronous alignment of the interlacing enhancement zone and the slub segment makes the slub segment cohesion more stable, significantly reduces bundle slippage and open filament scattering, improves the stability of the high-speed weaving process and reduces the risk of breakage; at the same time, the micro-fluff exposure is restricted to the corresponding slub segment, avoiding uneven hairiness and messy stripes caused by random looping throughout the length, making the slub texture clearer, the cotton-like fluffy hand feel more concentrated and the batch consistency better; without the need for complex processes such as gluing or coating, comprehensive optimization of appearance, hand feel and weavability can be achieved, making it suitable for the large-scale production of cotton-like filaments and their fabrics. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0019] I. Explanation of Basic Terminology Slub FDY: refers to polyester filaments formed through full drawing, exhibiting a linear density structure with alternating "regular segments" and "slub segments" along the filament length. The linear density of the slub segments is significantly higher than that of the regular segments. The formation of slub segments can be achieved through programmed drawing fluctuations, metering pump perturbations, and drawing roller speed fluctuations during the spinning process. This invention does not limit the specific method of slub formation in FDY.

[0020] Polyester POY: refers to pre-oriented polyester filament, which has a relatively low degree of orientation and crystallinity. It can exhibit high shrinkage potential after being heated. Under subsequent relaxation heat treatment conditions, it is more likely to produce length shrinkage, local ring formation and micro-ring structure.

[0021] Air interlocking (interlocking) and interlocking points (network points): refers to the use of high-speed compressed air from interlocking nozzles to generate turbulence / vortexes inside the yarn bundle, causing the bundled yarns to randomly entangle and form cohesion points (called interlocking points or network points), thereby improving the cohesion and weavability of the bundled yarns.

[0022] Enhanced / Reference Intersection Parameters: These refer to the influence of the intersection nozzle supply pressure (and, if necessary, nozzle airflow structure, nozzle model, etc.) on the intensity and density of the intersection point formation when under different settings. This invention employs at least a two-stage switching between "high pressure (enhanced)" and "low pressure (reference)" to achieve segmented intersection.

[0023] Bamboo segment position synchronization signal: This refers to a signal that characterizes "when / where the bamboo segment passes through the interlacing nozzle," and can come from online detection (such as laser diameter measurement, photoelectric diameter measurement, tension fluctuation feature recognition, image recognition) or from the filament feeding encoding signal / program timing signal at the bamboo segment FDY forming end. This invention preferably employs a combination of online detection and meter counting encoding to improve alignment accuracy.

[0024] Synchronization alignment error: refers to the deviation between the position of the intercalation enhancement zone and the bamboo node segment. For ease of quantification, this invention uses "the difference in distance between the center position of the enhancement intercalation zone and the center position of the bamboo node segment along the fiber length direction" as a preferred definition of alignment error. A boundary definition can also be used; those skilled in the art can implement this according to the specification without substantial deviation.

[0025] Dry heat shrinkage difference: The difference in shrinkage rates between component B and component A under specified dry heat conditions is used to characterize the magnitude of the "relative shrinkage driving force" generated by the composite yarn during thermal relaxation. Dry heat conditions can be achieved using a hot air oven or a hot plate device; reproducible experimental conditions are given in the embodiments of this specification.

[0026] II. Overall Technical Solution Concept and Core Mechanism Explanation 1. The key contradiction of the traditional approach In the development of composite filaments that achieve both a "slub-like appearance and cotton-like fluffiness," a common industry process combination is: slub filaments provide varying textures, POY provides heat shrinkage potential, and interlacing provides cohesive force. However, if the interlacing points are uniformly generated along the filament length, the following contradiction can easily arise in a slub FDY and POY bundled system: Contradiction A: The difference in stress between bamboo segments and regular segments leads to randomization of internodes. Bamboo segments have higher linear density and stronger instantaneous tension response. The cross-sectional shape, density, and airflow penetration path of the filament bundle when entering the interlocking nozzle are different. Under the same interlocking air pressure, the interlocking point may be "insufficiently generated" or "overly stacked" in the bamboo segment, resulting in insufficient local cohesion or hard nodes.

[0027] Contradiction B: POY heat shrinkage curling has a "position amplification effect". POY shrinks during relaxation heat treatment and tends to form micro-loops / micro-bulges. Intersection points are equivalent to "local locking points / anchor points". If the locking point positions are random, the exposed positions of the micro-loops are also random, resulting in uneven fabric hairs, messy stripes, and even obscuring the slub texture.

[0028] Contradiction C: Increasing the overall network strength to resolve randomization will have side effects. While increasing the overall interlocking pressure or interlocking point density may improve cohesion, it can easily lead to problems such as hard knots, stiff feel, increased friction and temperature, and increased breakage in the regular segment. It can also inhibit the formation of soft and fluffy POY in the target area.

[0029] Therefore, the fundamental problem with existing solutions is not whether there are intersections, but that the spatial distribution of intersection points lacks structural coordination with bamboo segments.

[0030] 2. The core mechanism of this invention: synchronous segmented locking and interlocking to construct a structural chain of "fixed-point anchoring - localized loop formation". This invention proposes that, during the air exchange process, the air supply pressure of the exchange nozzle is segmented and locked and modulated based on the synchronization signal of the bamboo segment position, thereby achieving: In the bamboo segment corresponding to the silk length section, enhanced interlacing parameters (higher air pressure) are applied to form an enhanced interlacing zone (the interlacing points are denser / stronger). In the remaining filament length sections, a reference interlacing parameter (lower air pressure) is used to form an interlacing reference zone (with sparser / softer interlacing points).

[0031] The resulting structural chain can be summarized as follows: Bamboo segments have "innate protrusions" and enhanced interlacing with "fixed-point anchoring".

[0032] Bamboo segments, due to their higher linear density, are essentially structural protrusions. Enhanced interlacing causes the interlacing points to be more concentrated in the corresponding sections of the bamboo segments, forming a stable, cohesive "anchoring zone." This anchoring zone can resist slippage and prevent the bamboo segments from fraying or becoming loose.

[0033] The thermal retraction force of POY is released in an orderly manner by the "anchoring zone". During the relaxation heat treatment, polyester POY generates a shrinkage driving force relative to slub FDY. When the interlacing points are concentrated in the corresponding sections of the slub segment, the shrinkage of POY is more likely to form controllable micro-rings exposed near the anchoring area, and presents a "cotton-like fluffiness" along the circumference of the slub segment. However, due to the weaker interlacing and sparse locking points in the regular section, the exposure of micro-rings is suppressed, thus forming an appearance of "fluffiness at the slub segment and cleanliness in the regular section".

[0034] Synchronous alignment error control ensures repeatability By controlling the alignment error between the enhanced interlacing zone and the bamboo segment to within ±10mm and ensuring that the enhanced zone covers no less than 60% of the bamboo segment, the structure formation has good batch stability, avoiding insufficient bamboo segment cohesion or excessive interlacing of conventional segments due to the offset of the enhanced interlacing.

[0035] Establish a "strong / weak partitioning" threshold based on the density ratio of intersection points. The density ratio of the intersection points between the reinforced zone and the reference zone is controlled at 1.5 to 4.0 times, so that the "strong and weak zones" can reflect the differences in the finishing process, but the reinforced zone is not too stiff or too dense, which would cause weaving friction and deterioration of hand feel.

[0036] The above mechanism enables the present invention to achieve the comprehensive effect of "clear slub appearance, cotton-like fluffiness and stable weavability" in an all-polyester system without relying on adhesives or coatings.

[0037] III. Systems and Process Equipment This invention can be implemented on conventional bundling and post-processing production lines. The following is a reproducible set of equipment: Bundling wire guide system: including tension frame, wire guide ceramic component, and bundling unit, which requires stable tension control capability.

[0038] Online detection module: laser diameter sensor, installed 0.5 to 1.5 m upstream of the interlacing nozzle, or tension sensor, sampling frequency ≥200 Hz; Meter wheel / encoder, used to convert detection signals into wire length position; Interchange module: Air interchange nozzle, equipped with a fast-response proportional valve or a two-position three-way solenoid valve, to achieve rapid switching of air supply pressure between enhanced and reference levels.

[0039] Relaxation heat treatment module: hot air relaxation furnace, hot roller box or hot plate channel are all acceptable; preferably, it has controllable relaxation ratio (set by the speed ratio of front and rear traction rollers) and stable temperature uniformity.

[0040] Winding module: Standard winding machine, as long as the winding tension is stable.

[0041] IV. Preparation Method and Steps The preparation method of this invention includes the following steps: S1 provides wire feeding and bundling. Slub FDY as component A and polyester POY as component B are placed on separate racks, and after passing through an independent tensioner, they are bundled together and enter the bundler, so that the two components form a stable bundle of bundled yarns before entering the interlacing nozzle.

[0042] The mass ratio of component A to component B is 30–70:70–30; The linear speed can be selected according to the equipment capacity, such as 600-1200 m / min.

[0043] S2 synchronous positioning An online detection module is arranged upstream of the interlacing nozzle to identify bamboo segments and output a synchronous signal indicating the position of the bamboo segments. The preferred method is as follows: Laser diameter measurement identification: As the diameter / equivalent linear density of bamboo segments increases, a peak appears in the diameter measurement curve; Tension feature identification: The tension of the bamboo segment exhibits characteristic fluctuations after entering the guide wire path; Metering encoding conversion: The moment when "the start point or center of the bamboo segment is detected" is converted into "silk length position" through the metering wheel, providing a trigger point for the switching of interlacing pressure.

[0044] To ensure that the alignment error is ≤±10mm, the following method can be used: after detecting a bamboo segment, compensation is performed according to a preset delay length (distance from the sensor to the nozzle) before triggering the cross-connection switch.

[0045] S3 segmented locking air communication Based on the synchronization signal of the bamboo segment position, the air supply pressure of the interlacing nozzle is controlled to switch between two levels in stages: By using higher air supply pressure in the filament length section corresponding to the bamboo joint segment, enhanced interlacing parameters are applied to form an interlacing enhancement zone; A reference crossover zone is formed by using a lower gas supply pressure and applying reference crossover parameters in the remaining filament length sections.

[0046] Preferred control parameters: Synchronous alignment: The center of the intercalating segment should be aligned with the center of the bamboo node segment as much as possible; the alignment error should be controlled to ≤±10mm; Coverage ratio: Enhance the coverage ratio of intercalating segments to bamboo segments ≥ 60%; Intersection point density ratio: The intersection point density in the enhanced region is 1.5 to 4.0 times that in the reference region; Pressure switching response: The faster the proportional valve or solenoid valve responds, the smaller the positioning error.

[0047] S4 relaxation heat treatment The cross-linked composite yarns are then fed into a relaxation heat treatment module and subjected to relaxation heat treatment at 160–200°C. This causes a 6–20% difference in dry heat shrinkage between component B and component A, and causes component B to form a ring / micro-fluffy exposed structure in the cross-linking reinforcement zone.

[0048] The preferred mode is "restricted relaxation": by setting the relaxation ratio of 1.03 to 1.20 by the speed ratio of the front and rear traction rollers in the hot zone, the shrinkage is released within a controllable range, avoiding excessive coiling throughout the process, which would result in a rough feel and uncontrolled appearance.

[0049] S5 winding forming After cooling and setting, the filaments are wound into tubes to obtain the finished slub-joint imitation cotton polyester filament.

[0050] V. Testing Methods The following standardized testing method was used, and all samples from the same batch were tested under the same conditions: 1. Intersection point density measurement Ten segments were randomly sampled, each 2m in length. The number of intersection points was counted, and the point density (points / m) was calculated. The point density and ratio of the corresponding sections (reinforced areas) of bamboo nodes and the corresponding sections (baseline areas) of regular segments were statistically analyzed.

[0051] 2. Measurement of synchronous alignment error The center of the protrusion, i.e. the center of the bamboo segment, is identified by diameter measurement, weighing, or visual inspection; the center of the segment with significantly high interlacing density, i.e. the center of the interlacing enhancement zone, is identified; and the difference in the distance between the two along the fiber length direction is calculated as the alignment error.

[0052] For each sample, 30 bamboo nodes were counted, and the average and maximum values ​​were calculated.

[0053] 3. Dry heat shrinkage rate and shrinkage difference Samples were allowed to shrink freely in a 180℃ hot air oven for 5 minutes, then removed and cooled to measure their length. The dry heat shrinkage rate S was then calculated.

[0054] The shrinkage rate of component A and component B was measured separately, and the difference in shrinkage rate was calculated.

[0055] 4. Ring / Slightly fluffy exposed index Under standard light source, a 1m sample is taken, and the number of exposed rings or the proportion of exposed length in the enhanced area and the reference area are counted. In this embodiment of the invention, the count is done manually.

[0056] 5. Evaluation of weaveability and fabric appearance Weaving breakage: Weave the same plain weave fabric on the same air-jet loom and record the number of breaks per 10,000 wefts or per 10,000 meters. If the number of breaks is less than 10,000, convert it to times / 10,000 wefts or times / 10,000 meters based on the actual number of breaks. Appearance rating: Three judges scored “clearness of bamboo joints, uniformity of feathers, cleanliness of stripes, and cotton-like feel” on a scale of 1 to 5 under blind evaluation conditions, and the average score was taken. Pilling tendency: Rated using Martindale pilling test, from 1 to 5.

[0057] VI. Examples and Comparative Examples The following examples and comparative examples all use PET raw material system. The only differences are in "whether the interlocking is synchronously segmented", "whether the interlocking is uniform", and "relaxation heat treatment and shrinkage difference control".

[0058] 1. Common raw materials and processes Component A (Bamboo Joint FDY): Nominal 75D / 72F; Component B (Polyester POY): Nominal 75D / 36F; Bundle mass ratio: A:B=50:50; Linear velocity: 900 m / min; Relaxation heat treatment: hot air passage, temperature 180℃, time approximately 2.5 minutes; Restricted relaxation ratio: 1.08.

[0059] Example 1 (E1): Synchronous segmented locking network.

[0060] Bamboo joint structure: The linear density of bamboo segments is 2.0 times that of regular segments; The length of the bamboo segment is 20mm; the internode spacing is 150mm.

[0061] Synchronous segmented network: Bamboo segment position synchronization signal: laser diameter measurement identification and meter counting encoding compensation; Interlocking nozzle air supply pressure: The standard section corresponds to the benchmark cross-sectional pressure in MPa. The corresponding section of the bamboo segment increases the interlocking pressure (MPa); Alignment control: The center of the reinforced section is aligned with the center of the bamboo node, with a target error of ≤±10mm; the reinforced section covers ≥80% of the bamboo node.

[0062] Relaxation heat treatment: 180℃, limited relaxation ratio 1.08.

[0063] The test sample standard consists of 3 batches, with 10 samples taken from each batch.

[0064] 2. Test Results The test results of Example 1 are shown in Tables 1 and 2.

[0065] Table 1. Results of E1 Structure and Process Control

[0066] Table 2 E1 Exposed and Weaving Properties

[0067] As shown in Tables 1 and 2, when the E1 sample was straightened on the table for observation, the bamboo joint section showed a "full but not hard" protrusion, and fine micro-rings were visible around the bamboo joint protrusion. The surface of the regular section was relatively clean. During the trial weaving on the loom, the opening was stable and the loosening phenomenon was significantly reduced.

[0068] Example 2 (E2): Increase the density ratio of bamboo nodes and moderately increase the interlacing strength.

[0069] Different from E1: bamboo segment linear density ratio is 2.6 times; bamboo segment length is 15mm; internode distance is 120mm; Interlocking pressure: MPa, MPa; the rest are the same.

[0070] The test results of Example 2 are shown in Table 3.

[0071] Table 3 Results of Key E2 Indicators

[0072] As shown in Table 3, when the bamboo nodes are more obvious, but the interlacing is stronger, some samples feel slightly "firm" in the bamboo node section, while the appearance still maintains a good cleanliness.

[0073] Example 3 (E3): Two-level network (pre-network full process, main network synchronous enhancement).

[0074] Unlike E1: It adds a pre-interlacing nozzle, forming basic cohesion at 0.14MPa throughout the process; The main interlocking nozzle adopts E1 synchronous segmentation: MPa, MPa.

[0075] The test results of Example 3 are shown in Table 4.

[0076] Table 4 E3 Key Indicator Results

[0077] As shown in Table 4, the two-level interlacing makes the bundling more stable, the alignment control easier, and the weaving breakage further reduced.

[0078] Example 4 (E4): Increase the proportion of polyester POY.

[0079] Unlike E1: A:B = 40:60; otherwise the same as E1.

[0080] The test results of Example 4 are shown in Table 5.

[0081] Table 5 Results of Key E4 Indicators

[0082] As shown in Table 5, the fluffiness is more pronounced, but the increased POY content makes the yarn bundle more sensitive to friction during high-speed weaving, resulting in a slight increase in yarn breakage.

[0083] Example 5 (E5): Restricted relaxation ratio adjustment.

[0084] Unlike E1, the restricted relaxation ratio is adjusted from 1.08 to 1.15 to release more retraction, while the baseline cross pressure is slightly reduced to 0.16 MPa to keep the regular segment clean.

[0085] The test results of Example 5 are shown in Table 6.

[0086] Table 6 Results of Key E5 Indicators

[0087] As shown in Table 6, at higher relaxation ratios, without synchronous segmented cross-linking, regular segments are more likely to form random loops.

[0088] Comparative Example Comparative Example 1 (C1): Unsegmented locking, asynchronous alignment, uniform interleaving.

[0089] It uses the same raw materials and bamboo-joint structure as E1, but the air supply pressure of the interlacing nozzle is constant at 0.28MPa, and the interlacing is uniform throughout; there is no synchronous signal control.

[0090] The test results for Comparative Example 1 are shown in Table 7.

[0091] Table 7 C1 Key Indicator Results

[0092] As shown in Table 7, the micro-rings are randomly exposed along the filament length, resulting in uneven fabric texture and dirty-looking stripes; some bamboo segments still have loose filaments / opening fluctuations.

[0093] Comparative Example 2 (C2): Segmented voltage regulation without synchronous alignment.

[0094] Similar to E1, but the enhanced interbranching pressure switching is triggered at a fixed cycle and is not synchronized with the position of the bamboo segment, resulting in a large misalignment between the enhanced area and the bamboo segment.

[0095] The test results for Comparative Example 2 are shown in Table 8.

[0096] Table 8 Results of C2 Key Indicators

[0097] As shown in Table 8, segmented pressure adjustment without synchronous alignment is equivalent to "applying enhanced interlocking in the wrong place," resulting in an increase in hard nodes in the regular segments and insufficient cohesion of bamboo segments, leading to unstable effects.

[0098] Comparative Example 3 (C3): Synchronous detection exists but voltage regulation is not segmented.

[0099] It uses the same detection system as E1, but the interlocking pressure is kept constant at 0.28MPa (without switching), and only bamboo joint signals are recorded.

[0100] The test results were similar to C1, with low scores for exposure randomization and appearance.

[0101] Comparative Example 4 (C4): Synchronous segmental cross-linking is established, but the shrinkage rate difference is insufficient.

[0102] Similar to E1, it uses synchronous segmented interlocking, but the relaxation heat treatment temperature is reduced to 150°C or the time is insufficient, resulting in only about 3-4%.

[0103] The test results for Comparative Example 4 are shown in Table 9.

[0104] Table 9 Results of C4 Key Indicators

[0105] As shown in Table 9, synchronous segmented interlacing provides "fixed-point anchoring," but without sufficient differential shrinkage driving force, it is difficult to form obvious micro-rings and a fluffy cotton feel, which illustrates the importance of shrinkage difference to the finished product effect.

[0106] VII. Comprehensive Comparison To facilitate a direct comparison, the key indicators of representative samples (E1 vs C1 vs C2) are summarized in Table 10.

[0107] Table 10: Comprehensive Comparison of Representative Samples

[0108] E1 concentrates the interlocking in the corresponding section of the bamboo segment, so that the POY thermal retraction is released in an orderly manner near the anchorage area and forms an exposed micro-ring. Therefore, the exposure concentration is significantly better than that of C1. C1 uniform interlacing results in the locking points being randomly distributed along the entire filament length, the starting position of POY loops being random, and the appearance being uneven with fuzziness. Although C2 is segmented, it is not aligned synchronously. The enhanced interlacing is applied to the wrong segment, which results in insufficient cohesion between the hard nodes and bamboo nodes of the regular segment. It can be seen that the present invention establishes a structure by synchronous segmented locking interlacing and differential shrinkage relaxation forming, achieving a balance between localized fluffiness at the bamboo joint segment and overall weavability, and has stable and repeatable process value.

[0109] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A type of slub-joint imitation cotton polyester filament, characterized in that: The filament is formed by bundling bamboo joint FDY as component A and polyester POY as component B and then interlacing them with air; component A has regular segments and bamboo joint segments alternately distributed along the filament length direction, the linear density of bamboo joint segments is 1.2 to 3.0 times that of regular segments, the length of bamboo joint segments is 5 to 50 mm, and the internode spacing is 50 to 300 mm. During air interlocking, based on the synchronous signal of the bamboo node position, enhanced interlocking parameters are used in the silk length section corresponding to the bamboo node, and reference interlocking parameters are used in the other silk length sections, thereby forming an enhanced interlocking zone and a reference interlocking zone along the silk length direction; the enhanced interlocking zone is synchronously aligned with the bamboo node with an alignment error ≤ ±10mm, the enhanced interlocking zone covers ≥60% of the bamboo node, and the density of interlocking points in the enhanced interlocking zone is 1.5 to 4.0 times that of the reference interlocking zone; The mass ratio of component A to component B is 30-70:70-30; after the filament is subjected to relaxation heat treatment at 160-200℃, component B forms a ring / micro-fluffy exposed structure in the interlacing reinforcement zone, and the difference in dry heat shrinkage rate between component B and component A is 6-20%.

2. The slub-joint imitation cotton polyester filament according to claim 1, characterized in that: The gas supply pressures of the interlocking nozzles corresponding to the enhanced interlocking parameters and the baseline interlocking parameters are 0.25–0.60 MPa and 0.10–0.25 MPa, respectively.

3. The slub-joint imitation cotton polyester filament according to claim 1, characterized in that: The bamboo segment position synchronization signal is obtained by any one or a combination of photoelectric / laser diameter measurement and identification, tension fluctuation feature identification, image recognition, or component A silk supply encoding signal.

4. The slub-joint imitation cotton polyester filament according to claim 1, characterized in that: The length of the intercalation enhancement zone is 0.8 to 1.5 times the length of the corresponding bamboo segment.

5. The slub-joint imitation cotton polyester filament according to claim 1, characterized in that: The equivalent overfeed rate of component B in the interlacing enhancement region is higher than that in the interlacing reference region, with a difference of 2-15%.

6. The slub-joint imitation cotton polyester filament according to claim 1, characterized in that: The air interlocking adopts a two-level interlocking method, including pre-interlocking and main interlocking. Pre-interlocking is used to form the reference interlocking point throughout the entire process, while main interlocking is used to form the enhanced interlocking point in the silk length section corresponding to the bamboo node segment.

7. A method for preparing the slub-joint imitation cotton polyester filament according to any one of claims 1 to 6, characterized in that, include: S1, yarn supply and bundling: Supply slub FDY as component A and polyester POY as component B and bundle them together; S2. Synchronous Positioning: Online detection of bamboo segment position or reading of component A silk supply code to obtain bamboo segment position synchronization signal; S3. Segmented locking air interlacing: Based on the synchronization signal, the air supply pressure of the interlacing nozzle is switched segment by segment. Enhanced interlacing parameters are used in the silk length section corresponding to the bamboo joint segment, and reference interlacing parameters are used in the other silk length sections to form an enhanced interlacing area and a reference interlacing area with a synchronous alignment error of ≤±10mm with the bamboo joint segment, a coverage ratio of ≥60%, and an interlacing point density ratio of 1.5~4.

0. S4. Relaxation heat treatment: The composite yarn after interlacing is subjected to relaxation heat treatment at 160-200℃, so that component B forms a ring / micro-loose exposed structure in the interlacing reinforcement zone and obtains a dry heat shrinkage rate difference of 6-20%. S5. Winding: The finished filament is obtained by winding.

8. The method according to claim 7, characterized in that: The online detection in step S2 uses laser diameter measurement or photoelectric detection to identify abrupt changes in the diameter of bamboo segments, and / or uses a tension sensor to identify the tension characteristics of bamboo segments.

9. The method according to claim 7, characterized in that: Step S3 corrects the gas supply pressure amplitude of the interlacing nozzle based on the online counting results of the interlacing points, so as to maintain the interlacing point density ratio between the interlacing enhancement zone and the interlacing reference zone at 1.5 to 4.

0.

10. The method according to claim 7, characterized in that: Step S4 is a restricted relaxation with a relaxation ratio of 1.03 to 1.20, in order to suppress random loop formation in the interlacing reference region and enhance the exposure of loops in the interlacing enhancement region.

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