Preparation method of high-resilience seamless clothes based on dual-channel heat setting

Abstract

The invention belongs to the technical field of textiles, particularly relates to a preparation method of high-resilience seamless clothes based on dual-channel heat setting, and aims to solve the problems of interface slippage and poor resilience durability caused by thermal response mismatch of nylon and elastic fibers in a traditional process. The method comprises the following steps: integrally weaving composite yarns of nylon coated elastic fibers on a seamless circular knitting machine to form a micropore array gray fabric penetrating through the thickness of the fabric, the aperture of micropores is 0.5-0.6 mm, and the density is 10-15 pores / cm < 2 >; the preparation method comprises the following steps: firstly, carrying out first-stage heat setting for 30-45 seconds under the conditions that the temperature is 110-120 DEG C and the relative humidity is 40-50%, and constructing a nylon pre-crystallization framework; and carrying out second-stage heat setting for 20-30 seconds in a saturated steam environment with the temperature of 160-170 DEG C and the relative humidity of not less than 95%, so that the elastic fibers are uniformly heated through micropores to generate phase change shrinkage, and are embedded into skeleton gaps to form a mechanical interlocking rebound network. Through the synergistic effect of step-by-step heat setting and micropore directional heat transfer, material performance decoupling and structural stability are achieved, the rebound consistency, the deformation recovery rate and the long-term use durability of clothes are remarkably improved, the process is compatible with existing equipment, and industrial popularization is facilitated.

Description

Technical Field

[0001] This application belongs to the field of textile technology, specifically relating to a method for preparing high-resilience seamless garments based on dual-channel heat setting. Background Technology

[0002] With the widespread application of functional close-fitting apparel in sports and health and everyday wear, seamless fabrics with high resilience and low residual deformation have become a key technological direction for improving wearing comfort and durability. Traditional seamless clothing often uses blended yarns of nylon and elastic fibers (such as spandex or polyether ester elastomers), achieving dimensional stability and elastic shaping through a single heat setting process. However, because nylon has a high glass transition temperature and melting point, while elastic fibers soften and shrink at lower temperatures, their thermal response behaviors differ significantly. This makes it difficult to simultaneously complete structural setting during conventional high-temperature setting processes, thus affecting the overall resilience and dimensional stability of the fabric.

[0003] Among them, the high-resilience seamless garment manufacturing method based on dual-channel heat setting focuses on solving the phase mismatch problem of different fiber components during heat treatment. This technology aims to construct a synergistic resilience mechanism by controlling the temperature and humidity environment in stages, allowing nylon to first form a stable crystalline skeleton, and then activating the shape memory phase transition of elastic fibers. Its core lies in precisely controlling the heat and moisture transfer path and the fiber response sequence to achieve functional integration at the microstructural level.

[0004] Existing technologies typically employ uniform high-temperature steam treatment, neglecting the fundamental differences in thermodynamic behavior between nylon and elastic fibers. This leads to excessive shrinkage of elastic fibers before nylon has fully crystallized, causing interfacial slippage and stress concentration. Simultaneously, conventional fabric structures lack directional heat and mass transfer channels, making it difficult for steam to penetrate evenly into the fabric interior. This results in uneven activation of elastic fibers, leading to delayed rebound or even permanent deformation in localized areas. Furthermore, current processes lack a systematic consideration of the coupling relationship between microstructure design and heat setting parameters, making it difficult to maintain the structural integrity of the fabric under multiple stretching cycles while ensuring high resilience. Therefore, a synergistic heat setting scheme that balances material property matching and structural heat transfer optimization is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing high-resilience seamless garments based on dual-channel heat setting, which solves the problems of interfacial slippage, poor resilience and durability, and uneven activation inside the fabric caused by the thermal response mismatch between nylon and elastic fibers in the prior art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing high-resilience seamless garments based on dual-channel heat setting includes the following specific steps:

[0008] Step (1) Using composite yarns with nylon-coated elastic fibers, a fabric with a microporous array is integrally woven on a seamless circular knitting machine:

[0009] The composite yarn consists of polyamide 66 as the outer sheath and a polyether ester elastomer as the inner core, compounded at a mass ratio of 80:20 to 85:15. The composite yarn has a core-sheath structure, where polyamide 66 completely covers the elastic fiber core, ensuring that the elastic fibers are not directly exposed to high temperatures during heat treatment. A microporous array penetrating the fabric thickness is simultaneously constructed during the weaving process using a seamless circular knitting machine. The micropores have a pore size of 0.5 mm to 0.6 mm and a density of 10 pores / cm². 2 Up to 15 holes / cm 2 The micropore array is regularly distributed on the fabric surface. The micropores penetrate the entire thickness direction of the fabric, the pore walls are smooth and burr-free, and the pore diameter tolerance is controlled within the allowable error range to ensure that the steam is efficiently conducted in the direction perpendicular to the fabric plane during the second stage of heat setting, avoiding local overheating or uneven activation caused by lateral diffusion.

[0010] Step (2) Perform the first stage of heat setting on the greige fabric:

[0011] Treatment at 110°C to 120°C and 40% to 50% relative humidity for 30 to 45 seconds induces initial orientation of the polyamide 66 molecular chains and forms a pre-crystalline framework. This framework possesses rigid support capabilities while retaining a certain degree of deformation space, with crystallinity controlled at 25% to 30%.

[0012] Under these temperature and humidity conditions, the polyamide 66 molecular chain segments gain enough energy to overcome local barriers and undergo directional migration and stacking along the fiber axis to form crystalline regions with a size of 10nm to 25nm. The crystalline regions are connected by amorphous regions to form a three-dimensional network skeleton, which provides sufficient rigid support to resist deformation in the subsequent high humidity environment, while retaining the flexibility of the amorphous regions to accommodate the shrinkage and deformation of the elastic fibers.

[0013] Step (3) allows the fabric to pass through a temperature and humidity transition buffer zone:

[0014] Between the first and second stages of heat setting, the fabric passes through a temperature and humidity transition buffer zone, with a length of 1.5m to 1.8m. Within the buffer zone, the temperature and relative humidity gradually change from the first stage conditions (110°C to 120°C, relative humidity 40% to 50%) to the second stage conditions (160°C to 170°C, relative humidity not less than 95%) according to a preset gradient, to prevent thermal shock or fiber damage to the fabric due to sudden environmental changes during the area transition.

[0015] Step (4) Perform the second stage of heat setting:

[0016] The fabric is treated for 20 to 30 seconds in a saturated steam environment at 160°C to 170°C and relative humidity of not less than 95%. The saturated steam penetrates into the fabric rapidly and uniformly in a direction perpendicular to the fabric plane through a microporous array as a directional heat and mass transfer channel, activating the shape memory phase of the elastic fibers, causing them to undergo a phase change and shrink.

[0017] Under these conditions, the polyether ester elastomer transforms from the α phase to the β phase, with a volume shrinkage rate of 15% to 20%. The shrunken elastic fibers tightly fill the microscopic voids in the pre-crystallized polyamide 66 skeleton, and their surfaces physically interlock with the amorphous regions of the skeleton, forming a mechanical anchoring structure in three-dimensional space.

[0018] Formation of the mechanically interlocked resilient network: The mechanically interlocked resilient network is composed of a pre-crystallized polyamide 66 skeleton and shrunken elastic fibers. The polyamide 66 skeleton provides tensile strength and dimensional stability, while the elastic fibers provide high resilience and deformation recovery. The two work synergistically at the microscale through physical interlocking rather than chemical bonding, avoiding interfacial delamination.

[0019] Seamless circular knitting machines are standard commercial models that do not require structural modifications to the equipment. They only need to embed micro-hole loop-forming instructions into the weaving program to simultaneously form a micro-hole array during the weaving process. They have strong process compatibility and are suitable for close-fitting clothing categories with high stretch requirements, such as yoga wear, sports bras, and compression garments.

[0020] Preferably, the greige fabric can undergo pre-relaxation treatment before entering the dual-zone heat setting machine to eliminate internal stress generated during weaving. Pre-relaxation is carried out for 55 to 60 seconds at 90°C to 95°C and relative humidity of 60% to 65% to ensure that the fabric dimensional changes are controllable during subsequent heat setting and to avoid deformation distortion caused by residual stress release.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. Achieve stepwise material response and resolve phase conflict issues.

[0023] By employing a dual-channel heat setting process, the crystallization of polyamide 66 and the phase transition of elastic fibers are decoupled into two independent and ordered thermodynamic processes. The first stage preferentially constructs a pre-crystallized polyamide 66 framework under medium-temperature and low-humidity conditions, preventing it from softening due to lack of setting in high-temperature and high-humidity environments. The second stage precisely activates the shape memory phase transition of the elastic fibers in high-temperature saturated steam. These two processes respond separately in time and space, significantly reducing interfacial slippage and stress concentration caused by differences in thermal response, thus resolving the core contradiction of phase mismatch between nylon and elastic fibers in traditional single heat setting processes.

[0024] 2. Microporous structure optimizes heat and moisture transfer paths, improving rebound consistency.

[0025] The microporous array embedded in the fabric serves as a directional heat and mass transfer channel, enabling saturated vapor to penetrate vertically through the fabric thickness during the second-stage heat setting, achieving uniform activation of the internal fibers. Compared to traditional dense fabrics that rely on slow lateral diffusion heat transfer, the microporous design of this invention significantly shortens the heat and moisture transfer path, ensuring that the elastic fibers in each region complete phase change and shrinkage simultaneously, thereby exhibiting highly consistent resilience on a macroscopic scale and avoiding localized relaxation or permanent deformation.

[0026] 3. Constructing a mechanically interlocked springback network significantly improves durability.

[0027] The polyamide 66 pre-crystallized skeleton and the shrunken elastic fibers form a physically interlocked structure at the microscale. This structure maintains interfacial integrity through mechanical anchoring during multiple stretch-rebound cycles. Experimental data shows that after 500 cycles of 50% strain stretching, the residual strain does not exceed 3% (2.7% in Example 1), and the springback recovery rate remains stable above 92% (93.5% in Example 1). This is far superior to the common residual strain of 5%-8% and springback recovery rate of around 85% in existing technologies, fully verifying the structural stability of the network under long-term dynamic loads.

[0028] 4. Excellent overall performance

[0029] Breathability: Air permeability reaches 135mm / s (coefficient of variation 2.4%), and moisture permeability reaches 1.01×10⁻⁶. 4 g / (m 2 • 24h); Anti-pilling performance: 3-4 levels, far superior to ordinary knitted fabrics; Anti-snagging performance: 3-4 levels in the straight direction and 4 levels in the transverse direction; Fit retention rate: higher than 95% after 500 cycles (96.2% in Example 1); Contact cooling coefficient: 0.21 J / (cm) 2 It provides a comfortable cool touch; it has excellent antistatic properties: the electrostatic half-life is only 0.052s.

[0030] 5. Strong process compatibility, lowering the threshold for industrialization.

[0031] The composite yarn used in this invention can be produced using conventional core-spun yarn technology, without the need for special customization; the micropore array is achieved through standard seamless circular knitting machine programming, requiring no equipment modification; the dual-zone heat setting parameters are all within the capabilities of existing heat setting machines. The overall process is simple and controllable, adaptable to existing seamless garment production lines, significantly reducing technology transfer costs and facilitating the large-scale commercial application of high-resilience functional garments. Attached Figure Description

[0032] Figure 1This is a schematic diagram of the process flow for the preparation method of high-resilience seamless garments based on dual-channel heat setting according to the present invention, showing the complete process from raw material weaving to dual-channel heat setting and then to the final product.

[0033] Appendix to the Instruction Manual

[0034] Table 1: Summary of Dual-Channel Heat Setting Process Parameters

[0035] Table 2: Summary of Performance Comparisons between Examples and Comparative Examples

[0036] Table 3: Microstructure Characterization Data of Example 1 Detailed Implementation Example 1

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0038] Currently, traditional seamless close-fitting garments often employ a single heat-setting process for nylon and elastic fiber blends. Because nylon's glass transition temperature (approximately 50°C) and melting point (approximately 220°C) are much higher than those of elastic fibers (e.g., spandex's softening point is approximately 180°C, but its optimal setting temperature is 160–170°C), during conventional high-temperature setting, nylon encounters excessive shrinkage of the elastic fibers before it has fully crystallized. This leads to interfacial slippage and phase mismatch, resulting in problems such as delayed rebound hysteresis and permanent deformation. Furthermore, existing fabric structures lack effective heat and mass transfer pathways, making it difficult for steam or hot air to penetrate evenly into the fabric, causing uneven activation of the elastic fibers and a decrease in localized rebound performance. Therefore, a synergistic setting solution that considers both material properties and structural heat transfer is urgently needed.

[0039] To address the aforementioned technical problems, this invention proposes a method for preparing high-resilience seamless garments based on dual-channel heat setting. Raw materials used in the examples:

[0040] Core elastic yarn: a core-spun yarn consisting of 85% polyamide 66 (40D) coated with 15% polyether ester elastic fiber (60D).

[0041] Loom: The loom is made of Italian Santoni SM8-TOP1 8-channel single-sided electronic jacquard seamless circular loom.

[0042] In the above-mentioned method for preparing high-resilience seamless garments based on dual-channel heat setting, step (1) involves using a composite yarn of nylon-coated elastic fibers, which is integrally woven on a seamless circular knitting machine to form a fabric with a microporous array. Specifically, the composite yarn consists of nylon as the outer layer and elastic fibers as the inner core. During the weaving process, a microporous array penetrating the fabric thickness is simultaneously constructed using a seamless circular knitting machine. The micropores have a predetermined pore size and density. The nylon material is polyamide 66, and the elastic fibers are polyether ester elastomers. The two are combined at a mass ratio of 85:15. The composite yarn structure is a core-wrapped structure, in which the nylon completely covers the elastic fiber core layer, ensuring that the elastic fibers are not directly exposed to the high-temperature environment during heat treatment. The microporous array is regularly distributed on the fabric surface. The micropores penetrate the entire thickness direction of the fabric, with smooth, burr-free pore walls and a pore size tolerance controlled within ±0.05 mm. This ensures that steam is efficiently conducted in the direction perpendicular to the fabric plane during the second stage of heat setting, avoiding local overheating or uneven activation caused by lateral diffusion. Seamless circular knitting machines are standard commercial models that require no structural modifications. Simply embedding micropore loop-forming instructions into the knitting program allows for the simultaneous formation of a micropore array during the weaving process. This provides strong process compatibility, making it suitable for close-fitting garments with high stretch requirements, such as yoga wear, sports bras, and compression clothing. During knitting, the micropore loop-forming instructions control the coordinated movement of the sinker plate on the needle bed and the needles, skipping loop-forming actions in specific fabric areas to create gaps that penetrate the fabric's thickness. These gaps, after subsequent heat treatment and setting, become micropores. The micropore diameter is set to 0.5mm, and the density is 10 pores / cm². 2 This parameter combination has been experimentally verified to achieve the efficiency of steam penetrating a 3mm thick fabric within 25 seconds, while maintaining the mechanical integrity of the fabric. Before entering the dual-zone heat setting machine, the greige fabric undergoes a pre-relaxation treatment to eliminate internal stress generated during weaving. The pre-relaxation is carried out at 95°C, 60% relative humidity, and a treatment time of 60 seconds to ensure that the fabric dimensional changes are controllable during the subsequent heat setting process and to avoid deformation distortion caused by the release of residual stress.

[0043] In the above-mentioned method for preparing high-resilience seamless garments based on dual-channel heat setting, step (2) involves the first stage of heat setting on the fabric: treating it at 110–120°C and 40–50% relative humidity for 30–45 seconds to induce the nylon molecular chains to undergo initial orientation and form a pre-crystalline skeleton. The skeleton has rigid support capabilities but retains a certain space for deformation. Specifically, the temperature, relative humidity, and treatment time for the first stage of heat setting are set to a combination of parameters of 115°C, 45% relative humidity, and 40 seconds, so that the polyamide 66 molecular chains can achieve orderly arrangement in the range below its melting point (220°C) but above its glass transition temperature (50°C), forming a pre-crystalline network with alternating distribution of nanoscale crystalline and amorphous regions. The network maintains structural stability in subsequent high-humidity and high-temperature environments. Under these temperature and humidity conditions, the polyamide 66 molecular chains gain sufficient energy to overcome local potential barriers, undergoing directional migration and stacking along the fiber axis to form crystalline regions with a size of 10–20 nm. These crystalline regions are connected by amorphous regions, forming a three-dimensional network framework. The crystallinity of the framework is controlled at 25%–30%. X-ray diffraction (XRD) testing in this embodiment shows an actual crystallinity of 28% and a crystalline region size of 18 nm (calculated using the Scherrer formula). This provides sufficient rigid support to resist deformation in subsequent high-humidity environments while retaining the flexibility of the amorphous regions to accommodate the shrinkage and deformation of the elastic fibers. The heat setting equipment uses the first zone of a dual-zone heat setting machine, which is equipped with an infrared radiation heating unit and an ultrasonic atomization humidification system. The infrared radiation power density is 5 kW / m². 2 (Wavelength range 2.5-15μm), atomized particle diameter 5μm, ensuring uniform distribution of temperature and humidity fields on and inside the fabric surface, with temperature fluctuation less than ±2°C and humidity fluctuation less than ±3%. The greige fabric passes through the first zone at a linear velocity of 1.2m / min and a residence time of 40s. This time is sufficient to complete the initial orientation of the molecular chains, but not enough to cause excessive crystallization leading to embrittlement.

[0044] In the above-mentioned method for preparing high-resilience seamless garments based on dual-channel heat setting, step (4) involves a second stage of heat setting: the garment is treated in a saturated steam environment at 160–170°C and relative humidity ≥95% for 20–30 seconds. The steam penetrates uniformly through microporous channels, activating the shape memory phase of the elastic fibers, causing them to undergo a phase change and shrink, embedding themselves into the gaps of the nylon pre-crystallized skeleton to form a mechanically interlocked elastic network. Specifically, the second stage of heat setting uses a saturated steam environment, with the temperature, relative humidity, and treatment time set to a parameter combination of 165°C, 98% relative humidity, and 25 seconds. Under these conditions, the elastic fibers transform from the α phase to the β phase, and the volume shrinkage rate is controlled within the range of 15%–20%. The shrunken elastic fibers tightly fill the microscopic gaps in the nylon skeleton, forming a three-dimensional mechanical anchoring structure. Saturated steam is generated by a boiler, adjusted to 0.3 MPa gauge pressure by a pressure reducing valve, and then evenly injected into the second zone of the dual-zone heat setting machine via a distributor. A microporous array serves as a directional heat and mass transfer channel, allowing steam to penetrate rapidly along a direction perpendicular to the fabric plane, achieving a penetration rate of 0.12 mm / s. This ensures that the elastic fibers in each layer of the fabric undergo phase transformation synchronously within 25 seconds. During the phase transformation, the hard segment microdomains of the polyether ester elastomer rearrange, transforming from a disordered α phase to an ordered β phase, accompanied by molecular chain coiling and volume shrinkage. The elastic fibers undergo phase transformation shrinkage, with a volume shrinkage rate of 18% (density before phase transformation: 1.15 g / cm³, determined by density method). 3 After the phase transition, the density is 1.40 g / cm³. 3 The surface of the nylon pre-crystallized skeleton forms a physical interlock with the amorphous region of the nylon, with an interlocking depth of 0.8–1.2 μm (observed and measured by transmission electron microscopy, TEM, magnification 50000×). The mechanically interlocked elastic network is composed of the nylon pre-crystallized skeleton and the shrunken elastic fibers. The nylon skeleton provides tensile strength and dimensional stability, while the elastic fibers provide high resilience and deformation recovery. The two work synergistically at the microscale through physical interlocking rather than chemical bonding, avoiding interfacial delamination. A temperature and humidity transition buffer section is set between the first and second zones of the dual-zone heat setter. The buffer section is 1.5 m long, and the temperature and relative humidity gradually change from 115°C / 45%RH to 165°C / 98%RH in a linear gradient within the buffer section. The heating rate is 33.3°C / m, and the humidification rate is 35.3% / m, preventing thermal shock or fiber damage to the fabric due to sudden environmental changes when switching zones.

[0045] In the aforementioned method for preparing high-resilience seamless garments based on dual-channel heat setting, the garments prepared by this method, after undergoing 500 cycles of 50% strain in high-dynamic tensile areas such as the knee joint, waist, abdomen, and shoulder blades, exhibit residual strain ≤3%, rebound recovery rate ≥92%, and fit retention rate >95%, indicating that they can maintain excellent morphological stability and wearing comfort during long-term use. The rebound recovery rate was determined using the ASTM D2594 standard test method (temperature 20±2°C, relative humidity 65±5%, sample size 200mm×50mm, clamping distance 100mm), residual strain was measured using digital image correlation (DIC) technology, and fit retention rate was calculated by comparing a three-dimensional human body scan with the initial model.

[0046] Long-term durability testing: The finished product of Example 1 was subjected to 5000 cycles of 50% strain. The results showed that the residual strain was 4.2% and the springback recovery rate was 90.5%, maintaining excellent resilience performance. In contrast, the control sample prepared using the conventional process had a residual strain of 12.5% ​​and a springback recovery rate of 78.2% after 5000 cycles.

[0047] Specific application example: the preparation of high-resilience yoga clothing.

[0048] First, prepare the composite yarn: use polyamide 66 filament (40D fineness, relative viscosity 2.4-2.6) as the outer layer and polyether ester elastomer filament (60D fineness, elastic modulus 500-600MPa) as the inner core. Use a ring spinning core-spun yarn machine to spin the core-spun yarn at a mass ratio of 85:15, control the wrapping angle at 15°, and the wrapping density at 80 twists / 10cm to ensure that the nylon layer completely covers the elastic fiber core with no exposed points.

[0049] Secondly, fabric weaving: On a seamless circular knitting machine (such as the Santoni SM8-TOP1 model), the aforementioned core-spun yarn is used as both the face and back yarns, programmed according to the yoga garment pattern. In high-stretch areas such as the knees, waist, and shoulders, micro-perforation looping instructions are embedded, setting the micro-perforation diameter to 0.5mm and the perforation spacing to 3.16mm (corresponding to a density of 10 holes / cm²). 2 The micropores are arranged in a square grid. During the weaving process, the loom needle speed is 120 rpm, and the yarn tension is controlled at 8 cN to ensure that the edges of the micropores are free of burrs and the pore walls are smooth. After weaving, the fabric undergoes a pre-relaxation treatment at 95°C, 60%RH, and 60s to eliminate internal stress.

[0050] Third, dual-channel heat setting: The pre-relaxed fabric is fed into a dual-zone heat setter. Zone 1 parameters: 115°C, 45%RH, 40s. Infrared heating and ultrasonic humidification work synergistically to form a pre-crystallized skeleton of polyamide 66 with 28% crystallinity. Subsequently, the fabric enters a 1.5m long buffer section, where the temperature and humidity linearly transition to 165°C / 98%RH. Zone 2 parameters: 165°C, 98%RH, 25s. Saturated steam penetrates vertically through micropores, activating the phase change of the elastic fibers. After the phase change, the elastic fibers shrink by 18% in volume, embedding themselves in the gaps of the nylon skeleton to form a mechanically interlocked structure. After the second stage of heat setting, the fabric is allowed to cool naturally at room temperature for 5 minutes, then washed (40°C pure water, 5 minutes), dehydrated (800rpm, 3 minutes), and air-dried naturally (room temperature, 24 hours).

[0051] Fourth, performance testing: The finished yoga wear underwent 500 cycles of 50% strain testing (according to ISO 13934-1, Tensile Properties of Fabrics Test Method, tensile rate 100 mm / min, preload force 2 N). Residual strain and rebound rate were determined according to ASTM D2594 standard. Fit retention was assessed using three-dimensional human body scanning (using [TC]). 2 Measurements were taken using a KX-16 3D scanner. Test results showed that the residual strain in the knee joint region was 2.7%, with a rebound recovery rate of 93.5%; the residual strain in the waist and abdomen region was 2.4%, with a rebound recovery rate of 94.1%; and the residual strain in the scapular region was 2.9%, with a rebound recovery rate of 92.8%. 3D scanning showed a fit retention rate of 96.2%. Microstructural analysis (SEM) confirmed a 1.0 μm physical interlocking between the nylon skeleton and the elastic fibers, with no interfacial delamination.

[0052] Fifth, process compatibility verification: The core-spun yarn used in this process can be produced by conventional ring spinning equipment; micro-perforation weaving only requires modification of the electronic jacquard program of Santoni SM8-TOP1, without hardware modification; the dual-zone heat setting parameters are all within the capability range of dual-zone heat setting equipment (such as Monforts Montex-Steamer 6000) (temperature range 30–180°C, humidity range 30–100%RH). Process compatibility testing shows that compared with the traditional single heat setting process, the process time of this invention increases by about 25% (from 96s / piece to 120s / piece), but the yield rate increases by 12% (from 82% to 94%), and the overall production efficiency increases by about 8%. In terms of equipment investment, only a buffer section needs to be added to the existing setting machine (costing about 50,000 yuan / unit), without replacing the main equipment. Example 2

[0053] Manufacturing of high-durability sports bras

[0054] In this embodiment, different material ratios and micropore parameters are used to meet the dual requirements of high breathability and high elasticity for sports underwear.

[0055] In the above-mentioned method for preparing high-resilience seamless garments based on dual-channel heat setting, step (1) involves using a composite yarn of nylon-coated elastic fibers, which is integrally woven on a seamless circular knitting machine to form a fabric with a microporous array. Specifically, the nylon material is polyamide 66, and the elastic fiber is a polyether ester elastomer, which are combined at a mass ratio of 80:20. The composite yarn structure is a core-spun structure, in which the nylon completely covers the elastic fiber core layer. The microporous array is distributed in a hexagonal honeycomb pattern on the fabric surface, with micropores penetrating the entire thickness direction of the fabric. The pore diameter is 0.6 mm, and the density is 15 pores / cm. 2 The pore walls are treated with plasma to control the surface roughness Ra at 0.2 μm, thereby enhancing the steam condensation nucleation effect and accelerating heat and moisture transfer. The fabric undergoes pre-relaxation treatment before entering the dual-zone heat setter, which is carried out at 90°C, 65% relative humidity, and a processing time of 55 seconds.

[0056] In the above-mentioned method for preparing high-resilience seamless garments based on dual-channel heat setting, step (2) involves the first stage of heat setting on the fabric: treatment at 118°C and 48% relative humidity for 38 seconds to form a pre-crystallized skeleton with a crystallinity of 26% for the polyamide 66 molecular chains. Under this parameter combination, the crystalline region size of the nylon skeleton is 15–25 nm, and the amorphous region accounts for 74%, providing sufficient flexibility to accommodate the shrinkage of a higher proportion of elastic fibers.

[0057] In the above-mentioned method for preparing high-resilience seamless garments based on dual-channel heat setting, step (4) involves a second stage of heat setting: treatment in a saturated steam environment at 168°C and 99% relative humidity for 22 seconds. Under these conditions, the volume shrinkage rate of the elastic fiber is 19%, and the surface of the shrunken fiber forms a micro-wrinkled structure, which forms multi-point anchoring with the amorphous region of the nylon skeleton, increasing the mechanical interlocking strength by 12%. The buffer section of the dual-zone heat setting machine has a length of 1.8m, and the temperature and humidity gradients are 27.8°C / m and 28.3% / m.

[0058] Specific application example: the preparation of high-durability sports underwear.

[0059] First, the composite yarn is prepared by spinning core-spun yarn with polyamide 66 (30D) and polyether ester elastomer (70D) at a mass ratio of 80:20, with a wrapping angle of 12° and a wrapping density of 85 twists / 10cm.

[0060] Secondly, fabric weaving: On a Lonati DL12 seamless circular knitting machine, micropores with a diameter of 0.6 mm and a density of 15 pores / cm are set in high sweat evaporation areas such as the armpits and back. 2The hexagonal arrangement is used. After weaving, the fabric is pre-relaxed at 90°C, 65%RH, and for 55 seconds.

[0061] Third, heat setting: Zone 1 118°C / 48%RH / 38s; Buffer zone 1.8m; Zone 2 168°C / 99%RH / 22s.

[0062] Fourth, performance testing: After 500 cycles of 50% strain, the residual strain in the underarm area was 2.5%, and the rebound rate was 94.3%; the air permeability (ASTM D737) reached 120 mm / s, which is 20% higher than that of Example 1.

[0063] Comparing Examples 1 and 2, it can be seen that when the proportion of elastic fibers increases from 15% to 20%, the rebound recovery rate increases from 93.5% to 94.3%, the residual strain decreases from 2.7% to 2.5%, and the air permeability increases by 20%. This indicates that appropriately increasing the proportion of elastic fibers and the micropore density is beneficial to improving resilience and air permeability. Example 3

[0064] To verify the full coverage of the parameter range of the claims, this embodiment uses an intermediate ratio and micropore parameters.

[0065] Main parameters:

[0066] Composite yarn weight ratio: 82:18

[0067] Micropore size: 0.55mm

[0068] Micropore density: 12 pores / cm 2

[0069] First stage heat setting: 113°C, 43%RH, 35s

[0070] Second stage heat setting: 163°C, 96%RH, 27s

[0071] Performance test results: After 500 cycles of 50% strain, the residual strain in the knee joint area was 2.6%, and the rebound recovery rate was 93.2%. Example 4

[0072] Main parameters: Composite yarn mass ratio: 80:20; Micropore diameter: 0.5mm; Micropore density: 10 pores / cm³ 2 The first stage of heat setting was 110°C, 40%RH, for 30 seconds; the second stage of heat setting was 160°C, 95%RH, for 20 seconds; the remaining steps were the same as in Example 1.

[0073] Performance test results: After 500 cycles of 50% strain, the residual strain in the knee joint area was 2.9%, and the rebound rate was 92.1%. XRD testing showed that the crystallinity of the pre-crystallized skeleton was 25%, and the crystal size was 10 nm. The volume shrinkage rate of the elastic fiber was 15%. Example 5

[0074] Main parameters:

[0075] Composite yarn mass ratio: 85:15; micropore size: 0.6 mm; micropore density: 15 pores / cm³ 2 The first stage of heat setting was 120°C, 50%RH, for 45 seconds; the second stage of heat setting was 170°C, 99%RH, for 30 seconds; the remaining steps were the same as in Example 1.

[0076] Performance test results: After 500 cycles of 50% strain, the residual strain in the knee joint area was 2.4%, and the rebound rate was 94.8%. XRD testing showed that the crystallinity of the pre-crystallized skeleton was 30%, and the crystal size was 25 nm. The volume shrinkage rate of the elastic fiber was 20%. Example 6 (Cross-validation)

[0077] Main parameters: Composite yarn mass ratio: 85:15; Micropore diameter: 0.6mm; Micropore density: 15 pores / cm³ 2 The first stage of heat setting was 115°C, 45%RH, for 40 seconds; the second stage of heat setting was 165°C, 98%RH, for 25 seconds; the remaining steps were the same as in Example 1.

[0078] Performance test results: After 500 cycles of 50% strain, the residual strain in the knee joint area was 2.5%, and the rebound recovery rate was 94.5%. The air permeability reached 130 mm / s.

[0079] Comparative Example 1

[0080] The same composite yarn and microporous array fabric as in Example 1 were used, but a conventional single heat setting process was employed.

[0081] Process parameters: One-time heat setting: 165°C, 95%RH, 60s;

[0082] Test results:

[0083] After 500 cycles of 50% strain, the residual strain in the knee joint area was 6.8%, and the rebound recovery rate was 85.3%.

[0084] Comparative Example 2

[0085] Fabrics using the same process but without microporous arrays are subjected to dual-channel heat setting.

[0086] Process parameters:

[0087] Same as in Example 1, but the fabric is a regular woven structure without microporous array.

[0088] Test results:

[0089] After 500 cycles of 50% strain, the residual strain in the knee joint area was 4.2%, the rebound recovery rate was 89.7%, and the fit retention rate was 91.3%.

[0090] Various testing standards

[0091] 1. Moisture permeability test:

[0092] GB / T 12704.12009, Test chamber environment: 38.0℃, 90.0% relative humidity, permeation time: 1h, Method: moisture absorption method.

[0093] 2. Air permeability (mm / s) test:

[0094] GB / T 54531997, pressure drop: 100Pa, test area: 20cm² 2 Face up.

[0095] 3. Anti-wrinkle performance (grade) test:

[0096] GB / T 29257-2012, Standard value and tolerance: Grade 34.

[0097] 4. Contact cooling coefficient test:

[0098] GB / T 35263-2017; Sample stage material: polystyrene foam; Instrument model: Roaches QMax; Hot plate temperature: 35.0℃; Cold plate temperature: 20.0℃.

[0099] 5. Abrasion resistance (10,000 revolutions) (cycles) Front test:

[0100] GB / T 21196.22007, Load: 9kPa, Abrasive: Wool abrasive.

[0101] 6. Static voltage half-life test:

[0102] GB / T 12703.12021, Temperature: 20.1℃, Relative Humidity: 37.5%.

[0103] 7. Washability test:

[0104] Size variation: GB / T 86292017A type, washing machine program: 10x4N, hanging to dry.

[0105] Post-drying test: GB / T 13769-2009 A type washing machine 5-wash-dry cycle program: 5A, tumble drying.

[0106] To clearly illustrate the process parameter settings of this invention, the parameters for each stage are summarized below (see Table 1):

[0107] Table 1 Summary of Dual-Channel Heat Setting Process Parameters

[0108]

[0109] To visually compare the performance differences between the present invention and the prior art, the test results of each sample are summarized as follows (see Table 2):

[0110] Table 2 Summary of performance comparison between the examples and comparative examples

[0111]

[0112] Table Notes:

[0113] The data in Example 1 and Comparative Example 1 are test results for the knee joint area. The data in Example 2 are test results for the axillary region.

[0114] The data from Example 3 and Comparative Example 2 are test results for the knee joint area.

[0115] Comparative analysis:

[0116] 1. The effect of dual-channel heat setting: Comparing Example 1 and Comparative Example 1, it can be seen that after adopting the dual-channel heat setting process, the residual strain decreased from 6.8% to 2.7% (a reduction of 60%), and the elasticity recovery rate increased from 85.3% to 93.5% (an increase of 9.6%). This indicates that dual-channel heat setting effectively solves the problem of thermal response mismatch between nylon and elastic fibers through a step-by-step response mechanism.

[0117] 2. The effect of the microporous array: Comparing Example 1 and Comparative Example 2, it can be seen that the microporous array reduced the residual strain from 4.2% to 2.7% (a reduction of 36%), and increased the springback recovery rate from 89.7% to 93.5% (an increase of 4.2%). This indicates that the microporous array achieves uniform activation of the elastic fibers by optimizing the heat and moisture transfer path.

[0118] 3. Impact of parameter optimization: Comparing Example 1 and Example 2, it can be seen that when the proportion of elastic fibers increases from 15% to 20% and the micropore density increases from 10 pores / cm, the effect of parameter optimization is significantly improved. 2 Increased to 15 holes / cm 2At that time, the rebound rate increased from 93.5% to 94.3%, and the air permeability increased from 100mm / s to 120mm / s (an increase of 20%). This indicates that appropriately increasing the proportion of elastic fibers and micropore density is beneficial to improving rebound performance and air permeability.

[0119] 4. Long-term durability comparison: After 5000 cycles, the residual strain of Example 1 was 4.2% and the springback recovery rate was 90.5%, while the residual strain of Comparative Example 1 after 5000 cycles reached 12.5% ​​and the springback recovery rate dropped to 78.2%. The mechanically interlocked springback network of the present invention shows significant advantages in long-term use.

[0120] Table 3 Microstructure characterization data

[0121]

[0122] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high-resilience seamless garments based on dual-channel heat setting, comprising the following steps: A composite yarn consisting of nylon-coated elastic fibers is integrally woven on a seamless circular knitting machine to form a fabric with a microporous array. The composite yarn consists of nylon as the outer sheath and elastic fibers as the inner core. The microporous array has a pore size of 0.5 mm to 0.6 mm and a density of 10 pores / cm². 2 Up to 15 holes / cm 2 The micropores penetrate the thickness direction of the fabric and are arranged in a square grid or hexagonal honeycomb pattern on the fabric surface; The fabric is subjected to a first-stage heat setting at 110°C to 120°C and 40% to 50% relative humidity for 30 to 45 seconds, so that the nylon molecular chains are initially oriented and form a pre-crystallized skeleton with rigid support capacity but retaining deformation space. Between the first and second stages of heat setting, the fabric passes through a temperature and humidity transition buffer zone, where the temperature and relative humidity gradually change from the first stage conditions to the second stage conditions in a gradient. The second stage of heat setting is carried out by treating the fabric in a saturated steam environment at 160°C to 170°C and relative humidity of not less than 95% for 20 to 30 seconds. The saturated steam penetrates vertically into the fabric through the microporous array, activating the shape memory phase of the elastic fibers, causing them to undergo a phase change and shrink. The shrunken elastic fibers are embedded in the gaps of the pre-crystallized skeleton, forming a mechanically interlocked rebound network composed of the nylon skeleton and the elastic fibers.

2. The method for preparing high-resilience seamless garments based on dual-channel heat setting according to claim 1, characterized in that, The fabric undergoes a pre-relaxation treatment before entering the first stage of heat setting. The pre-relaxation is carried out for 55 to 60 seconds at 90°C to 95°C and relative humidity of 60% to 65% to eliminate internal stress during weaving.

3. The method for preparing high-resilience seamless garments based on dual-channel heat setting according to claim 1, characterized in that, The first stage of heat setting is carried out at a temperature of 110°C to 120°C, a relative humidity of 40% to 50%, and a processing time of 30s to 45s, so that polyamide 66 forms a pre-crystallized skeleton with a crystallinity of 25% to 30%.

4. The method for preparing high-resilience seamless garments based on dual-channel heat setting according to claim 1, characterized in that, The second stage of heat setting is carried out at a temperature of 160°C to 170°C, with a relative humidity of not less than 95% and a processing time of 20 to 30 seconds, causing the elastic fibers to undergo thermal phase change shrinkage with a volume shrinkage rate of 15% to 20%.

5. The method for preparing high-resilience seamless garments based on dual-channel heat setting according to claim 1, characterized in that, The temperature and humidity transition buffer section is 1.5m to 1.8m long, and the temperature and relative humidity gradually change from the first stage conditions to the second stage conditions within the buffer section according to a gradient.

6. The method for preparing high-resilience seamless garments based on dual-channel heat setting according to claim 1, characterized in that, The micropore array is formed by embedding a micropore loop-forming instruction in the seamless circular knitting program. This instruction controls the knitting needles to skip the loop-forming action at a predetermined position, forming micropores that penetrate the thickness of the fabric.

7. The method for preparing high-resilience seamless garments based on dual-channel heat setting according to claim 1, characterized in that, In the mechanically interlocked spring network, the shrunken elastic fibers and the amorphous regions of the nylon pre-crystallized skeleton form a physical interlock, and the two achieve a synergistic effect through mechanical anchoring in three-dimensional space.

8. A high-resilience seamless composite yarn for clothing, comprising a nylon outer sheath and an elastic fiber inner core, wherein the nylon is polyamide 66, the elastic fiber is a polyether ester elastomer, the polyamide 66 has a mass percentage content of 80wt%-85wt%, the polyether ester elastomer has a mass percentage content of 15wt%-20wt%, and the nylon completely covers the elastic fiber core.

9. A high-resilience seamless garment fabric, woven from composite yarns of nylon-coated elastic fibers, wherein: The composite yarn consists of polyamide 66 as an outer layer and polyether ester elastomer as an inner core, with a mass ratio of 80:20 to 85:

15. The polyamide 66 completely covers the elastic fiber core layer. The fabric surface has a micropore array with a pore size of 0.5 mm to 0.6 mm and a density of 10 pores / cm². 2 Up to 15 holes / cm 2 The micropores penetrate the thickness direction of the fabric and are arranged in a square grid or hexagonal honeycomb pattern on the fabric surface.

10. A high-resilience seamless garment prepared by the method of any one of claims 1 to 7, wherein after 500 cycles of 50% strain in the knee joint, waist and abdomen or scapular region, the residual strain does not exceed 3%, the rebound recovery rate is not less than 92%, and the fit retention rate is higher than 95%.

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