High-density stretch denim fabric and production process

Abstract

The present application relates to a kind of high-density four-way stretch denim fabric and production process, belong to the technical field of textile fabric.The warp yarn is arranged by 7s slub yarn and 75D+20D spandex core yarn according to 1:1 proportion, weft yarn adopts double elastic yarn, total warp root number is 7700, finished product width is 154-156cm.Production process includes ball warp beaming, string dyeing, heavy warp machine winding, double warp beam sizing, harness threading, weaving and post-finishing;Double warp beam makes the tension of two kinds of warp yarn be controlled respectively, cooperates 1,5,2,6,3,7,4,8 fancy harness threading and 1-4 pieces and 5-8 pieces layering configuration, effectively eliminates weaving defects;Post-finishing uses water desizing and loose drying.The present application realizes bidirectional high elasticity of warp and weft while maintaining the style of jean slub, and the fabric is flat and dimensionally stable.

Description

Technical Field

[0001] This invention relates to the field of textile fabric technology, specifically to a high-density four-way stretch denim fabric and its production process. Background Technology

[0002] Four-way stretch denim fabric, with its elastic elongation and recovery capabilities in both warp and weft, provides excellent comfort and fit, and has gained widespread consumer favor in recent years, becoming an important development direction in the denim fabric industry. Currently, four-way stretch denim fabric typically achieves its two-way elasticity by introducing elastic yarns in both the warp and weft directions. The warp elasticity often utilizes elastic yarn systems such as cotton-wrapped spandex, cotton-wrapped polyester, or cotton-wrapped polyester-wrapped spandex. However, existing four-way stretch denim fabrics still face many technical challenges in production and application. First, the warp shrinkage rate is relatively high and fluctuates significantly, requiring extremely strict control in finishing processes; even slight deviations can lead to excessive shrinkage. Second, the fabric's dimensional stability is generally poor, posing significant difficulties for garment factories in pattern design and cutting processes. Furthermore, four-way stretch denim fabrics containing spandex suffer from inherent defects such as spandex's inability to withstand high temperatures and alkalis, and its susceptibility to aging; with increased wear time and washing cycles, the fabric's elasticity gradually loosens and may even be lost. Meanwhile, existing products also struggle to achieve a good balance in terms of feel. If warp elasticity is prioritized over fabric firmness, the fabric often becomes too soft and lacks structure, lowering its overall quality. Conversely, sacrificing elasticity for a stiffer feel fails to meet consumer demand for comfort. Furthermore, high-elasticity warp yarns are prone to problems such as fabric width narrowing and hem curling during weaving, significantly complicating production. These combined issues result in high quality control difficulties and low product yield for four-way stretch denim fabric, hindering its large-scale promotion and application.

[0003] To further enrich the style expression of denim fabrics, some four-way stretch denim fabrics incorporate slub yarn into the warp yarns to achieve a denim style with a slub texture and retro feel. When slub yarn and elastic core-spun yarn are mixed and arranged in a certain ratio (e.g., 1:1) as warp yarns, there are significant differences in the fiber composition, elastic modulus, shrinkage properties, and surface morphology of the two yarns—slub yarn is a short-fiber yarn with a loose structure, high stiffness, and low elongation; elastic core-spun yarn contains spandex elastic filaments, with low elastic modulus, high elongation, and high shrinkage. When both are fed on the same warp beam with the same tension, the difference in elongation results in varying degrees of warp elongation, leading to severely uneven tension distribution during weaving. This makes the fabric surface prone to defects such as wrinkles, warp shrinkage, and uneven weft density. Even with the use of dual warp beams to control the warp tension of the two warp yarns separately, the lack of a matching differentiated heddle threading process and warp layering configuration means that the mutual interference and tension fluctuations of the two warp yarns during shedding cannot be effectively eliminated. Furthermore, in rope dyeing, the mixed warp yarn system containing slub yarn and elastic yarn is prone to uneven dyeing and color differences due to the different dye adsorption properties of the two yarns. In the finishing process, the alkali agents and high-temperature treatments in conventional desizing processes can cause irreversible elastic damage to the spandex fibers in the elastic core-spun yarn, further exacerbating the contradiction between maintaining fabric elasticity and dimensional stability. Therefore, how to retain the retro denim style provided by slub yarn while solving the above-mentioned technical problems in the weaving, dyeing, and finishing processes of the mixed warp yarn system of slub yarn and elastic core-spun yarn has become a technical bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0004] In order to solve the problems of the prior art, the present invention provides a high-density four-way stretch denim fabric and its production process.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: Firstly, a high-density four-way stretch denim fabric, comprising warp yarns and weft yarns, wherein the warp yarns include A yarn and B yarn, and the arrangement ratio of A yarn to B yarn is 1:1; the A yarn is 7s slub yarn, and the B yarn is 75D+20D Lycra core-spun yarn; the weft yarn is (TAR)8 / (70+75D) double stretch yarn; the total number of warp yarns in the fabric is 7700, the number of inner warp yarns is 7620, the number of edge warp yarns is 80, the weft density after weaving is 38 yarns / cm, and the finished width is 154-156cm.

[0006] In one specific embodiment of the first aspect, the warp yarns are woven using a double warp beam, with the A yarn and B yarn respectively disposed on different warp beams.

[0007] In one specific embodiment of the first aspect, the warp yarns of the fabric are threaded in the following manner: the B yarn is threaded through heddles 1, 2, 3, and 4, and the A yarn is threaded through heddles 5, 6, 7, and 8; the inner warp yarns are threaded in the following order: 1, 5, 2, 6, 3, 7, 4, and 8; and the edge warp yarns are threaded through heddles 1 and 2.

[0008] In one specific embodiment of the first aspect, the fabric has a box number of 49, an inner warp count of 4, a side warp count of 4, and a box width of 78.57 cm.

[0009] In one specific embodiment of the first aspect, the fabric is JR Magnolia.

[0010] Secondly, a production process for a high-density four-way stretch denim fabric includes the following steps: (1) Ball warp alignment; (2) Rope dyeing; (3) Rewinding on a warp winding machine; (4) Sizing: Sizing is performed using two warp beams, with yarn A and yarn B placed on different warp beams; (5) Threading heddles and reeds; (6) Weaving: Weaving is carried out using a double warp beam loom; (7) Post-processing: singeing, desizing with water, drying, shaping and pre-shrinking are carried out in sequence.

[0011] The beneficial effects of this invention are as follows: 1. This invention effectively solves the weaving difficulties caused by tension differences when weaving warp yarns with different properties on the same axis in existing technologies, through the synergistic cooperation of independent warp feed control on two warp beams and a differentiated heddle structure. Specifically, this invention sets the elastic core-spun yarn and slub yarn on the upper and lower warp beams respectively, each equipped with an independent warp feed tension adjustment system. This ensures that both types of warp yarns maintain a constant tension output during weaving, avoiding differences in warp elongation caused by differences in yarn elastic modulus, thereby significantly reducing the probability of fabric wrinkling and warp breakage. Simultaneously, the use of layered heddle patterns (1, 2, 3, 4 and 5, 6, 7, 8) and fancy heddle sequence (1, 5, 2, 6, 3, 7, 4, 8) creates alternating movement trajectories for the two types of warp yarns during the shedding process, effectively dispersing dynamic tension peaks during weaving and further ensuring the stability of warp yarn operation. The resulting denim fabric has a smooth and uniform surface with consistent weft density, completely eliminating fabric defects such as horizontal bars and arching caused by uneven tension in traditional single warp beam weaving. 2. Based on the elasticity retention requirements of four-way stretch denim fabric, this invention constructs a systematic low-tension processing system throughout the entire process from warp preparation to finishing. In the sizing stage, appropriate sizing temperature ranges are set according to the fiber composition of the two warp yarns, avoiding high-temperature damage to the elasticity of the spandex fibers in the elastic core-spun yarn, while ensuring sufficient sizing of the slub yarn, providing strong support for subsequent weaving. In the finishing process, a combination of water desizing and loose drying effectively removes sizing agents while avoiding chemical corrosion and thermal shrinkage of the elastic fibers by alkalis and high temperatures, maintaining the original elastic recovery ability of the warp elastic yarns. Combined with tension optimization control in the setting and pre-shrinking processes, the internal stress of the fabric under humid and hot conditions is fully released, and the warp and weft dimensions tend to stabilize. Through the comprehensive application of the above technical means, this invention achieves excellent elastic elongation and elastic recovery performance in both warp and weft directions while maintaining the traditional slub texture characteristics and retro style of denim fabric, while also taking into account the dimensional stability and color fastness of the fabric, resulting in a significantly superior overall quality compared to similar products. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the double warp shaft threading and reed structure of the high-density four-way stretch denim fabric of the present invention. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all 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 scope of protection of the present invention.

[0014] like Figure 1 This paper shows a high-density four-way stretch denim fabric and its production process.

[0015] (a) Ball warp alignment The full width of warp yarn is divided into several bundles according to the capacity of the yarn bobbin, with each bundle containing 350-400 warp yarns. After being bundled with equal tension, the yarns are cross-wound into spherical or cylindrical packages. During the warping process, the tension of each yarn is controlled to be uniform, with the tension deviation controlled within ±5%. The warping length is 10,000-15,000 meters.

[0016] Input: Package yarn (A yarn 7s slub yarn, B yarn 75D+20D Lycra core-spun yarn); Output: Spherical or cylindrical warp yarn rolls.

[0017] Process parameters: Number of warp yarns per bundle: 350–400; Warping length: 10,000–15,000 m; Single yarn tension deviation: ≤±5%.

[0018] (2) Rope dyeing 12 to 36 strands of rope-like warp yarns are fed side-by-side into a continuous dyeing machine for rope dyeing. Indigo dye or a dye of the corresponding color family (JR Magnolia in this example) is used for dyeing, and the dyeing process is completed through multiple immersion and oxidation cycles. The advantages of rope dyeing are uniform and stable dyeing, smaller transverse color difference in the finished fabric, and a neat appearance and soft, comfortable feel.

[0019] After dyeing, the warp yarns are rope-like. After washing to remove excess dye, they proceed to the next process.

[0020] Input: Warp rolls after warping; Output: Dyed rope-like warp yarns.

[0021] Process parameters: Rope strand count: 12–36 strands; Number of immersions: 6 to 8; Oxidation time: 3-5 min / cycle; Staining temperature: room temperature to 50℃; Reduction temperature: 45~55℃.

[0022] (iii) Re-warping machine winding After dyeing, the rope-like warp yarns are dispersed and wound into individual warp yarns on a re-warping machine, and then rewound into warp beams according to the required total number of warp yarns (7700). Since this product is woven with double warp beams, it needs to be wound into two warp beams: the upper beam (B yarn, 3850 yarns) and the lower beam (A yarn, 3850 yarns).

[0023] Input: Dyed rope-like warp yarns; Output: Double warp beam (3850 B yarns on the upper warp beam and 3850 A yarns on the lower warp beam).

[0024] Process parameters: Number of warp yarns on the upper shaft: 3850 (B yarn); Number of warp yarns on the lower shaft: 3850 (A yarn); Winding tension: The tension of the upper shaft is slightly less than that of the lower shaft.

[0025] (iv) Sizing Sizing is performed on two warp beams separately. Due to the significant performance differences between yarn A (7s slub yarn) and yarn B (75D+20D Lycra core-spun yarn), the sizing process parameters need to be controlled separately.

[0026] A-type sizing: 7S slub yarn is cotton fiber yarn, sized using conventional starch-based sizing agents or environmentally friendly sizing agents. Sizing temperature is controlled at 85-95℃, sizing speed at 30-50m / min, and sizing rate at 8%-12%. Sizing of B-yarn: 75D+20D Lycra core-spun yarn contains elastic fibers, so the sizing temperature should be appropriately reduced to avoid damaging the elasticity of the Lycra fibers due to high temperatures. The sizing temperature should be controlled at 75–85℃, the sizing speed at 25–40 m / min, and the sizing rate at 6%–10%. During the sizing process, the warp tension should be kept uniform to avoid excessive stretching of the elastic yarn.

[0027] Input: Double warp beam (upper warp beam B yarn, lower warp beam A yarn).

[0028] Output: Twin propeller shaft.

[0029] Process parameters: Sizing temperature for yarn A: 85~95℃; Sizing temperature for yarn B: 75~85℃; Sizing speed: 25-50 m / min; Sizing rate of yarn A: 8%~12%; Sizing rate of yarn B: 6%~10%; (v) Threading heddles and reeds After sizing, the warp yarns are threaded through heddles and reeds according to the designed process.

[0030] Inner warp threading: A patterned threading method is used, with the threading sequence being 1, 5, 2, 6, 3, 7, 4, 8. Yarn B is threaded through heddles 1, 2, 3, and 4 (upper warp); yarn A is threaded through heddles 5, 6, 7, and 8 (lower warp).

[0031] Border warp: warp 1 and 2 warp pieces.

[0032] Reed: Inner warp number 4, side warp number 4, box number 49.

[0033] Input: Twin propeller shaft; Output: The warp beam completed by threading the heddles and reeds.

[0034] (vi) Weaving The weaving is performed using a double warp beam loom. The double warp beam allows for separate control of the feed tension of the two warp yarns. The tension of the upper beam (B yarn, Lycra core-spun yarn) should be slightly less than that of the lower beam (A yarn, slub yarn) to ensure that the two warp yarns are fed out synchronously during the weaving process, avoiding fabric wrinkling or warp yarn breakage.

[0035] The loom used is either a rapier loom or an air-jet loom, and the fabric structure is a twill weave. The weft density is 38 threads / cm. During the weaving process, strict control of workshop temperature and humidity is required, with the temperature maintained between 25 and 30°C and the relative humidity between 65% and 75%.

[0036] Input: warp beam completed by heddle and reed threading + weft yarn ((TAR)8 / (70+75D) double elastic yarn).

[0037] Output: Denim greige fabric.

[0038] Process parameters: Upper shaft tension: slightly less than lower shaft tension; Weft density: 38 threads / cm; Workshop temperature: 25~30℃; Workshop relative humidity: 65%~75%.

[0039] (vii) Post-processing The finishing process is as follows: singeing, desizing with clean water, loose drying, setting, and pre-shrinking.

[0040] 1. Singeing A singeing machine is used to remove fuzz from the fabric surface, resulting in a smooth and even surface. The singeing nozzle temperature is 900–1000℃, and the machine speed is 60–80 m / min. After singeing, the fabric surface should be smooth and free of obvious fuzz.

[0041] Input: Denim greige fabric.

[0042] Output: Singed fabric.

[0043] Process parameters: Singeing temperature: 900~1000℃; Vehicle speed: 60~80m / min.

[0044] 2. Desizing with clean water This product uses a water-based desizing process and is specifically designed for four-way stretch denim fabrics. The desizing tank temperature is controlled at 55–60℃, and the desizing time is 20–30 minutes. During the desizing process, the pH value of the desizing solution must be controlled between 6 and 7. Desizing should be thorough, with a desizing rate of ≥90%, while avoiding high-temperature damage to the elastic fibers.

[0045] Input: singed fabric.

[0046] Output: Desized fabric.

[0047] Process parameters: Desizing temperature: 55~60℃.

[0048] Desizing time: 20-30 minutes.

[0049] pH value: 6-7.

[0050] Desizing rate: ≥90%.

[0051] 3. Loose drying A loose-feature drying system is used to avoid excessive tension affecting the fabric's elasticity. The drying temperature is controlled at 100–120℃, and the machine speed is 30–50 m / min. The moisture content of the fabric after drying is controlled at 5%–8%.

[0052] Input: Fabric after desizing.

[0053] Output: Dried fabric.

[0054] Process parameters: Drying temperature: 100~120℃; Vehicle speed: 30-50 m / min; Finished product moisture content: 5%~8%.

[0055] 4. Shaping The setting process stabilizes fabric dimensions and controls shrinkage rates in both warp and weft directions. The setting temperature is 160–170℃, the setting speed is 30–50 m / min, the overfeed rate is 10%–15%, and the setting width is 148–152 cm. During the setting process, care must be taken to protect the elasticity of the Lycra fibers and avoid excessively high temperatures that could lead to elasticity loss.

[0056] Input: Fabric after drying.

[0057] Output: Fabric after shaping.

[0058] Process parameters: Setting temperature: 160~170℃; Setting speed: 30-50 m / min; Overfeeding rate for shaping: 10%–15%; Standard width: 148~152cm.

[0059] 5. Pre-shrinkage The final pre-shrinking treatment eliminates potential shrinkage stress in the fabric, ensuring that the warp and weft shrinkage rates of the finished product are controlled to ≤12%. Pre-shrinking is performed using a steam pre-shrinking machine at a temperature of 100–110℃ and a speed of 20–30 m / min. After pre-shrinking, the finished product width meets the requirement of 154–156 cm.

[0060] Input: Fabric after shaping.

[0061] Output: Finished fabric.

[0062] Process parameters: Pre-shrinkage temperature: 100~110℃; Vehicle speed: 20-30 m / min; Finished width: 154-156cm.

[0063] V. Examples Example 1 Raw material preparation: Yarn A: 7s slub yarn (YJ0396), 3850 strands; B yarn: 75D+20D Lycra core-spun yarn, 3850 ends; Weft yarn: (TAR) 8 / (70+75D) double stretch yarn.

[0064] Process flow: (1) Warping of the ball: Warp A yarn and B yarn separately, with 380 yarns per bundle and a warping length of 12,000m. The tension deviation of the single yarn is controlled within ±5%.

[0065] (2) Rope dyeing: 24 rope-shaped warp yarns are fed into a continuous dyeing machine in parallel and dyed with indigo dye to achieve JR black magnolia color. The dyeing is carried out 7 times, with each oxidation lasting 4 minutes. The dyeing temperature is 45℃ and the reduction temperature is 50℃.

[0066] (3) Warping on a re-warping machine: The dyed rope-like warp yarns are dispersed and wound into single warp yarns, which are then wound into an upper shaft (3850 B yarns) and a lower shaft (3850 A yarns).

[0067] (4) Sizing: A yarn sizing temperature 90℃, sizing speed 40m / min, sizing rate 10%; B yarn sizing temperature 80℃, sizing speed 35m / min, sizing rate 8%.

[0068] (5) Threading heddles and reeds: The inner warp threading sequence is 1, 5, 2, 6, 3, 7, 4, 8. B yarn is threaded through 1-4 heddles, and A yarn is threaded through 5-8 heddles; the edge warp is threaded through 1 and 2 heddles; thread the reed 4 times, box number 49.

[0069] (6) Weaving: A double warp beam rapier loom is used, with the upper beam tension slightly less than the lower beam tension. The lower beam weft density is 38 threads / cm. The workshop temperature is 28℃ and the relative humidity is 70%.

[0070] (7) Post-processing: Singeing: Temperature 950℃, speed 70m / min; Desizing with clean water: temperature 58℃, time 25min, pH value 6.5; Loose drying: temperature 110℃, speed 40m / min.

[0071] Setting: Temperature 165℃, speed 40m / min, overfeed rate 12%, width 150cm.

[0072] Pre-shrinkage: Temperature 105℃, vehicle speed 25m / min.

[0073] Finished product inspection: Finished width: 155cm; Warp elongation: 28%; Weft elastic elongation: 32%; Warp shrinkage rate: -8%; Weft shrinkage rate: -6%; Color fastness (wash fastness): ≥4.

[0074] Example 2 The difference from Example 1 is as follows: (1) Rope staining: immersion 6 times, oxidation 3 min each time, staining temperature 40℃, reduction temperature 45℃.

[0075] (2) Sizing: A yarn sizing temperature 88℃, sizing speed 45m / min, sizing rate 9%; B yarn sizing temperature 78℃, sizing speed 30m / min, sizing rate 7%.

[0076] (3) Post-processing: Desizing with clean water: temperature 55℃, time 30min, pH value 6.0; Setting: Temperature 160℃, speed 35m / min, overfeed rate 15%, width 148cm; Pre-shrinkage: Temperature 100℃, vehicle speed 30m / min.

[0077] The remaining process parameters are the same as in Example 1.

[0078] Finished product inspection: Finished width: 154cm; Warp elongation: 26%; Weft elastic elongation: 30%; Warp shrinkage rate: -9%; Weft shrinkage rate: -7%; Color fastness (wash fastness): ≥4.

[0079] Example 3 The difference from Example 1 is as follows: (1) Rope staining: immersion 8 times, oxidation 5 min each time, staining temperature 50℃, reduction temperature 55℃.

[0080] (2) Sizing: A yarn sizing temperature 92℃, sizing speed 35m / min, sizing rate 11%; B yarn sizing temperature 82℃, sizing speed 40m / min, sizing rate 9%.

[0081] (3) Post-processing: Desizing with clean water: temperature 60℃, time 20min, pH value 7.0.

[0082] Setting: Temperature 170℃, speed 45m / min, overfeed rate 10%, width 152cm; Pre-shrinkage: Temperature 110℃, vehicle speed 20m / min; The remaining process parameters are the same as in Example 1.

[0083] Finished product inspection: Finished width: 156cm; Warp elongation: 30%; Weft elastic elongation: 35%; Warp shrinkage rate: -7%; Weft shrinkage rate: -5%; Color fastness (wash fastness): ≥4.

[0084] VI. Experimental Examples Experimental Example 1: Fabric Elasticity Test.

[0085] Test method: The test was conducted in accordance with the FZ / T 13036-2016 standard "Yarn-dyed stretch denim". A constant load method was used: a 50N load was applied, held for 10 minutes, and then the elongation was measured. After release, the recovery was measured.

[0086] Test results: ; Results analysis: The warp and weft elastic elongation of the three embodiments were all ≥26%, and the elastic recovery rate was all ≥90%, which met the elasticity requirements of four-way stretch denim fabric.

[0087] Experimental Example 2: Fabric Dimensional Stability Test.

[0088] Test method: The test was conducted in accordance with GB / T 8628-2013 "Preparation, marking and measurement of fabric samples and garments for the test of dimensional change in textiles" and GB / T 8629-2017 "Domestic washing and drying procedures for testing textiles". The dimensional change rate of the samples was measured after 5 standard washes.

[0089] Test results: ; Results analysis: The warp and weft shrinkage rates of the three embodiments are all ≤9%, which meets the dimensional stability requirements of four-way stretch denim fabric.

[0090] Experimental Example 3: Fabric color fastness test.

[0091] Test method: The test was conducted in accordance with GB / T 3921-2008 "Textiles - Tests for color fastness to washing" and GB / T3920-2008 "Textiles - Tests for color fastness to rubbing".

[0092] Test results: ; Results analysis: All color fastness indicators of the three embodiments met or exceeded the industry standard requirements.

[0093] Experiment Example 4: Testing of the physical and mechanical properties of fabrics.

[0094] Test methods: The tests were conducted in accordance with GB / T 3923.1-2013 "Textiles - Tensile properties of fabrics - Part 1: Determination of breaking strength and elongation at break (strip method)" and GB / T 19976-2005 "Textiles - Determination of bursting strength - Steel ball method".

[0095] Test results: ; Results analysis: All physical and mechanical performance indicators of the three embodiments met or exceeded the industry standard requirements.

[0096] VII. Comparative Experiment Comparative Experiment 1: Comparison of single warp beam and double warp beam weaving.

[0097] Experimental objective: To verify the effect of double warp beam weaving on improving the quality of four-way stretch denim fabric compared to single warp beam weaving.

[0098] Experimental plan: Example 1: Double warp beam weaving (A yarn and B yarn are set on different warp beams).

[0099] Comparative Example 1: Single warp beam weaving (yarn A and yarn B are on the same warp beam), with the remaining process parameters the same as in Example 1.

[0100] Test results: ; Results analysis: Example 1, which uses double warp beam weaving, significantly outperforms Comparative Example 1, which uses single warp beam weaving, in terms of fabric wrinkling rate, warp breakage rate, and weft density unevenness. It also exhibits higher warp elastic elongation. This indicates that double warp beam weaving can effectively solve weaving problems caused by the differences in the properties of the two warp yarns.

[0101] Comparative Experiment 2: Comparison of different heddle threading methods.

[0102] Experimental objective: To verify the influence of the pattern threading method (1, 5, 2, 6, 3, 7, 4, 8) of the present invention on the fabric style.

[0103] Experimental plan: Example 1: Using a pattern (1, 5, 2, 6, 3, 7, 4, 8).

[0104] Comparative Example 2: The sequential threading method (1, 2, 3, 4, 5, 6, 7, 8) was adopted, and the remaining process parameters were the same as in Example 1.

[0105] Test results: ; Results analysis: Example 1, which uses a patterned weave, has a clear bamboo texture, a uniform fabric surface, and a soft feel, which better meets the style requirements of denim fabric; while Example 2, which uses a straight weave, has a blurry bamboo texture, warp stripes on the fabric surface, and does not perform well in terms of denim style.

[0106] Comparative Experiment 3: Comparison of different finishing processes.

[0107] Experimental objective: To verify the effects of the finishing process of this invention (singeing, desizing with water, loose drying, setting, and pre-shrinking) on ​​the elasticity and dimensional stability of four-way stretch denim fabric.

[0108] Experimental plan: Example 1: The post-finishing process of the present invention is adopted.

[0109] Comparative Example 3: The conventional finishing process (singeing, alkali desizing, high-temperature drying, shaping, and pre-shrinking) was adopted, and the remaining process parameters were the same as those in Example 1.

[0110] Test results: ; Results Analysis: Example 1, employing the clean water desizing + loose drying process of this invention, significantly outperformed Comparative Example 3, which used the conventional alkali desizing + high-temperature drying process, in terms of both elastic elongation and shrinkage. This indicates that the finishing process of this invention can better protect the elasticity of elastic fibers while effectively controlling shrinkage.

[0111] Comparative Experiment 4: Comparison of different weft yarn configurations.

[0112] Experimental objective: To verify the contribution of the weft yarn ((TAR)8 / (70+75D) double elastic yarn) of the present invention to the weft elasticity.

[0113] Experimental plan: Example 1: The weft yarn is (TAR) 8 / (70+75D) double elastic yarn.

[0114] Comparative Example 4: The weft yarn is ordinary polyester-spandex core-spun yarn, and the other process parameters are the same as in Example 1.

[0115] Test results: ; Results analysis: Example 1, which uses (TAR) 8 / (70+75D) double elastic yarn, is superior to Comparative Example 4, which uses ordinary polyester-spandex core-spun yarn, in terms of weft elastic elongation, elastic recovery rate, hand feel, and wrinkle resistance.

[0116] The high-density four-way stretch denim fabric and its production process of this invention achieve a balance between high elasticity and high density in both warp and weft directions through double-warp weaving, rope dyeing, and optimized finishing processes. The fabric retains the slub style and retro texture of traditional denim while also offering the comfortable wearing experience of four-way stretch, with a warp and weft elastic elongation rate ≥25% and a warp and weft shrinkage rate ≤12%. The process of this invention is stable and reliable, suitable for mass industrial production, and can be widely used in high-end jeans, denim jackets, and other apparel products.

[0117] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-density four-way stretch denim fabric, characterized in that, The fabric includes warp and weft yarns. The warp yarns consist of A yarn and B yarn, with an arrangement ratio of 1:

1. The A yarn is 7s slub yarn, and the B yarn is 75D+20D Lycra core-spun yarn. The weft yarn is (TAR)8 / (70+75D) double elastic yarn. The total number of warp yarns in the fabric is 7700, the inner warp yarns are 7620, the edge warp yarns are 80, the weft density is 38 weft threads / cm, and the finished width is 154-156cm.

2. The high-density four-way stretch denim fabric according to claim 1, characterized in that, The warp yarns are woven using a double warp beam, with the A yarn and B yarn respectively set on different warp beams.

3. The high-density four-way stretch denim fabric according to claim 1, characterized in that, The warp threading method of the fabric is as follows: the B yarn is threaded through heddles 1, 2, 3, and 4, and the A yarn is threaded through heddles 5, 6, 7, and 8; the inner warp threading sequence is 1, 5, 2, 6, 3, 7, 4, and 8; the edge warp is threaded through heddles 1 and 2.

4. The high-density four-way stretch denim fabric according to claim 1, characterized in that, The fabric has a box number of 49, an inner warp count of 4, a side warp count of 4, and a box width of 78.57cm.

5. The high-density four-way stretch denim fabric according to claim 1, characterized in that, The fabric is JR Magnolia.

6. A manufacturing process for high-density four-way stretch denim fabric as described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Ball warp alignment; (2) Rope dyeing; (3) Rewinding on a warp winding machine; (4) Sizing: Sizing is performed using two warp beams, with yarn A and yarn B placed on different warp beams; (5) Threading heddles and reeds; (6) Weaving: Weaving is carried out using a double warp beam loom; (7) Post-processing: singeing, desizing with water, drying, shaping and pre-shrinking are carried out in sequence.

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