Knitted twill cooling denim fabric for leggings

Abstract

Provided is a knitted twill cooling denim fabric for leggings. Also provided is a method for preparing a knitted twill cooling denim fabric for leggings. Further provided is the use of the knitted twill cooling denim fabric in leggings.

Description

FIELD OF TECHNOLOGY

[0001] The present disclosure is related to the field of textile, in particular, to a knitted twill cooling denim fabric for leggings.BACKGROUND

[0002] After development and evolution in more than one hundred years, denim clothing has always been loved by people due to its unique style while undergoing small changes in type and design. The improvement on the denim clothing lies more in the wearing comfort and functionality. Evolved from simple woven twill cloth, the denim fabric is currently obtained by weaving with a variety of yarns with different structural properties, including knitted denim, imitation denim, printed denim, etc., accumulating a variety of styles through continuous development.

[0003] In hot summers, people require clothing with a cool-feeling effect. When people exercise outdoors, they sweat heavily. Due to the limited space and weak convection between the skin and clothing, sweat evaporates slowly, preventing the efficient dissipation of body heat and resulting in stuffiness and discomfort. Current technologies often apply cooling agent finishing to fabrics, such as mint-based cooling agents, but these provide suboptimal user experiences, and the cooling effect diminishes significantly with repeated washing.SUMMARY

[0004] The present disclosure provides a knitted twill cooling denim fabric for leggings, addressing the drawbacks of existing fabrics where cooling agent finishing is applied to the fabric but results in suboptimal experiential effects and near-complete loss of the cooling effect with increased washing cycles, thereby providing a denim fabric with enhanced contact cooling performance.

[0005] In the first aspect, the present disclosure provides a knitted twill cooling denim fabric for leggings. The fabric adopts a single-sided three-track knitted structure including multiple minimum stitch repeat units. Each of the minimum stitch repeat units includes three wale columns and six-position course rows. A structural unit formed by a first wale and the six-position course rows is configured as follows: loop-forming stitch units are formed at positions 2, 4, 5, and 6 of the six-position course rows; and float stitch units are formed at positions 1 and 3 of the six-position course rows. A structural unit formed by a second wale and the six-position course rows is configured as follows: float stitch units are formed at positions 1 and 5 of the six-position course rows; and loop-forming stitch units are formed at positions 2, 3, 4, and 6 of the six-position course rows. A structural unit formed by a third wale and the six-position course rows is configured as follows: loop-forming stitch units are formed at positions 1, 2, 4, and 6 of the six-position course rows; and float stitch units are formed at positions 3 and 5 of the six-position course rows.

[0006] In the second aspect, the present disclosure provides a method for preparing a knitted twill cooling denim fabric for leggings, including: knitting with yarns to form a grey fabric, followed by post-finishing treatments to obtain the desired fabric.

[0007] In the third aspect, the present disclosure provides the use of a knitted twill cooling denim fabric in the production of leggings.

[0008] The knitted twill cooling denim fabric for leggings provided by the present disclosure has the following advantages.

[0009] (1) Compared to traditional denim fabrics with post-sanforized finishing, the knitted twill cooling denim fabric of the present disclosure exhibits a tight texture, substantial weight, vibrant coloration, and distinct weave patterns. Through yarn selection, structural design, patterning, and finishing techniques, this fabric achieves the visual appearance and woven-like texture of traditional denim while offering superior softness and comfort over traditional denim fabrics.

[0010] (2) The knitted twill cooling denim fabric of the present disclosure demonstrates significantly enhanced elasticity compared to traditional denim fabrics.

[0011] (3) The knitted twill cooling denim fabric of the present disclosure also retains the traditional twill texture in appearance. Controlled dyeing processes further enable gradated wash-down effects akin to those of traditional denim fabrics.

[0012] (4) By integrating the loop-forming properties of the knitted structure with inherently cooling filament fibers, the knitted twill cooling denim fabric of present disclosure maximizes skin contact with the cooling side of the fabric, delivering instant cooling sensations.

[0013] (5) Through performance evaluations of elasticity, lightweight properties, moisture permeability, and cooling performance, the knitted twill cooling denim fabric of the present disclosure demonstrates its comfort advantages. The fabric provides permanent cooling effects, resolving the issue of water wash-induced degradation of cooling performance in conventionally treated fabrics (e.g., cooling agent finishing). Compared to traditional woven stretch denim garments, this fabric significantly reduces heat retention during wear, while its elasticity and lightweight characteristics surpass those of garments made from traditional woven stretch denim fabrics.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a knitting diagram of a knitted twill cooling denim fabric for leggings in the present disclosure, where 1 is a cylinder knitting needle; 2 is a loop-forming stitch unit knitted using the cylinder knitting needle; and 3 is a float stitch unit knitted using the cylinder knitting needle; 11 to 16 represent positions 1 to 6 of the six-position course rows, respectively; and 21 represent a minimum stitch repeat unit.

[0015] FIG. 2 is an actual stitch diagram of the knitted twill cooling denim fabric for leggings in the present disclosure, where 11 to 16 represent positions 1 to 6 of the six-position course rows, respectively.DETAILED DESCRIPTION

[0016] The following provides detailed descriptions of the embodiments of a knitted twill cooling denim fabric for leggings in the present disclosure. However, certain detailed explanations may be omitted where appropriate. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. This is to prevent unnecessary prolixity in the following descriptions and to facilitate comprehension by those skilled in the art. In addition, the following descriptions are provided for those skilled in the art to fully understand the present disclosure and are not intended to limit the subject matter defined in the claims.DEFINITION OF TERMS

[0017] In weft-knitted fabrics, the loop-forming stitch units indicate full needle engagement where the knitting needle completes the entire loop-forming process, creating intermeshed loops. Thus, the loop-forming stitch units are also referred to as loop structural units. The float stitch units indicate zero needle engagement, producing linear yarn floats on the fabric's technical back, alternatively termed non-knitting units.

[0018] In the knitted fabric, a row of loops aligned along the fabric's width is referred to as a course, while a column of vertically interlooped loops constitutes a wale. For an n-position course row (where n is a positive integer not less than 1), the positions are sequentially designated as position 1, position 2 . . . position n from left to right. Correspondingly, n wale columns (where n is a positive integer ≥1) are sequentially designated as wale 1, wale 2 . . . wale n from top to bottom.

[0019] The “range” disclosed in the present disclosure is defined in the form of a lower limit and an upper limit, where a specified range is bounded by selecting a lower boundary and an upper boundary. The range defined in this way may be inclusive or exclusive of the end values and may be combined arbitrarily. That is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if minimum range values of 1 and 2 are listed, and maximum range values of 3, 4, and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present disclosure, unless otherwise specified, the numerical range “a-b” represents an abbreviation for any combination of real numbers between a and b, wherein a and b are both real numbers. For example, the numerical range “0-5” means that all real numbers between “0-5” have been listed in this article, and “0-5” is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0020] Unless otherwise specified, all embodiments and optional embodiments of the present disclosure can be combined with each other to form a new technical solution.

[0021] Unless otherwise specified, all technical features and optional technical features of the present disclosure can be combined with each other to form a new technical solution.

[0022] Unless otherwise specified, all the steps of the present disclosure can be performed sequentially or in any arbitrary order, preferably sequentially. For example, a method comprising steps (1) and (2), indicates that the method may include steps (1) and (2) performed sequentially, or alternatively steps (2) and (1) performed sequentially. When the method is described as optionally comprising step (3), it indicates that step (3) may be incorporated in any sequence permutation. For example, the method may include steps (1), (2), and (3), or may include steps (1), (3) and (2), or may include steps (3), (2) and (1), etc.

[0023] Unless otherwise specified, the terms “including” and “comprising” as used in the present disclosure shall be construed as either open-ended or closed-ended. For example, the terms “including” and “comprising” may indicate that additional unlisted components may also be encompassed, or may be limited to solely the explicitly listed components.

[0024] Unless otherwise specified, in the present disclosure, the term “or” is inclusive. For example, the phrase “A or B” shall be interpreted as “A, B, or both A and B.” More specifically, any of the following conditions satisfies the requirement of “A or B”: A is true (or present) and B is false (or absent); A is false (or absent) and B is true (or present); or both A and B are true (or present).

[0025] In the first aspect, the present disclosure provides a knitted twill cooling denim fabric for leggings. As shown in FIGS. 1 and 2, the fabric adopts a single-sided three-track knitted structure including multiple minimum stitch repeat units. Each of the minimum stitch repeat units includes three wale columns and six-position course rows.

[0026] A structural unit formed by a first wale and the six-position course rows is configured as follows: loop-forming stitch units are formed at positions 2, 4, 5, and 6 of the six-position course rows; and float stitch units are formed at positions 1 and 3 of the six-position course rows.

[0027] A structural unit formed by a second wale and the six-position course rows is configured as follows: float stitch units are formed at positions 1 and 5 of the six-position course rows; and loop-forming stitch units are formed at positions 2, 3, 4, and 6 of the six-position course rows.

[0028] A structural unit formed by a third wale and the six-position course rows is configured as follows: loop-forming stitch units are formed at positions 1, 2, 4, and 6 of the six-position course rows; and float stitch units are formed at positions 3 and 5 of the six-position course rows.

[0029] In the above fabric, the back side of the fabric is in a twill appearance.

[0030] In the second aspect, the present disclosure provides a method for preparing a knitted twill cooling denim fabric for leggings, including: knitting with yarns to form a grey fabric, followed by post-finishing treatments to obtain the desired fabric.

[0031] In the above method, the yarns are filament yarns, cellulosic yarns, or elastic fibers.

[0032] In some embodiments, the filament yarns are chemically modified fibers with cooling properties, including but not limited to polyester and nylon. Specifically, the material of the filament yarns is polyester or nylon.

[0033] In some embodiments, a material of the cellulosic yarns includes but is not limited to cotton, linen, viscose, and lyocell. Specifically, the material of the cellulosic yarns is cotton, linen, viscose, or lyocell.

[0034] In some embodiments, a material of the elastic fibers includes but is not limited to spandex and polyolefin. Specifically, the material of the elastic fibers is spandex or polyolefin.

[0035] In some embodiments, two types of yarns are used for knitting. The positions 1, 3, and 5 of the six-position course rows employ filament yarns; and the positions 2, 4, and 6 of the six-position course rows employ cellulosic yarns and elastic fibers knitted simultaneously.

[0036] In some embodiments, the ratio of filament yarns, cellulosic yarns, and elastic fibers is 1:1:1.

[0037] In the above method, the knitting process is performed using a single-sided four-track circular knitting machine operated in a single-sided three-track knitting mode.

[0038] In the above method, the single-sided three-track knitting process employs three-step needles for the cylinder knitting needles, with the cylinder needle arrangement following an ABC cyclic pattern.

[0039] In the above method, the knitting process forms a minimum stitch repeat unit using three wales and six-position course rows, and constructs the fabric surface through multiple such units to obtain a grey fabric.

[0040] In some embodiments, in the minimum stitch repeat unit, loop-forming stitch units are formed by the first wale with positions 2, 4, 5, and 6 of the 6-position course rows; float stitch units are formed by the first wale with positions 1 and 3 of the 6-position course rows; float stitch units are formed by the second wale with positions 1 and 5 of the 6-position course rows; loop-forming stitch units are formed by the second wale with positions 2, 3, 4, and 6 of the 6-position course rows; loop-forming stitch units are formed by the third wale with positions 1, 2, 4, and 6 of the 6-position course rows; and float stitch units are formed by the third wale with positions 3 and 5 of the 6-position course rows. The detailed structure of the minimum stitch repeat unit is shown in Table 1.TABLE 1First wale——Second wale——Third wale——six-positionPositionPositionPositionPositionPositionPositioncourse123456In Table 1,  represents a loop-forming stitch unit, and — represents a float stitch unit.

[0041] In the above method, the post-finishing treatments include: singeing, scouring, alkali weight reduction, dyeing, and setting of the grey fabric. In some embodiments, the singeing is performed using a gas singeing machine.

[0042] In some embodiments, the singeing parameters are as follows: flame application with one front and one back pass (double-sided singeing); fabric speed controlled at 80-120 m / min, such as 80-100 m / min or 100-120 m / min; distance between fabric and flame maintained at 0.8-1.0 cm, such as 0.8-0.9 cm or 0.9-1.0 cm; gasoline vaporization rate set to 20-25 kg / h, such as 20-23 kg / h or 23-25 kg / h; and vaporization temperature ≥80° C., preferably 80° C.

[0043] During spinning and weaving, mechanical friction generates excessive lint on the fabric. The singeing can remove the lint.

[0044] In some embodiments, the scouring is performed by using caustic soda, a degreasing agent, a scouring agent, and other scouring auxiliaries. The scouring can remove oiling agents and impurities from fibers.

[0045] Specifically, under controlled temperature in an alkaline bath, caustic soda, degreasing agents, scouring agents, and other auxiliaries act through dissolution, degradation, and emulsification, a portion of impurities is directly dissolved in the scouring liquor; another portion, whose adhesion to fibers is weakened by swelling, is removed from the fabric through washing; the remaining portion is stripped off via the emulsifying action of the auxiliaries.

[0046] In some embodiments, a dosage of the caustic soda added to the scouring liquor ranges from 3 to 5 g / L, such as 3-4 g / L and 4-5 g / L. The caustic soda is sodium hydroxide.

[0047] In some embodiments, the degreasing agent is conventional. Specifically, the degreasing agent is TF-101H Special Oil Remover produced by Transfar Chemical, which is in the form of a solid powder.

[0048] The primary components of the degreasing agent include inorganic salt and a surfactant, which play a key role in oil removal during scouring.

[0049] In some embodiments, a dosage of the degreasing agent added to the scouring liquor ranges from 1 to 1.5 g / L, such as 1-1.3 g / L and 1.3-1.5 g / L. In some embodiments, the scouring agent is conventional. Specifically, the scouring agent is a blend of phosphate ester surfactants and fatty alcohol polyoxyethylene ethers, which enhances the thermal stability of the fabric in the solution. The scouring agent is in the form of a solid powder.

[0050] In some embodiments, a dosage of the scouring agent added to the scouring liquor ranges from 1 to 2 g / L, such as 1-1.5 g / L and 1.5-2 g / L.

[0051] In some embodiments, the other scouring auxiliaries include sodium silicate and sodium bisulfite, which are used to adsorb impurities and improve fabric whiteness, respectively.

[0052] In some embodiments, a dosage of the sodium silicate added to the scouring liquor ranges from 1.5 to 3 g / L, such as 1.5-2 g / L and 2-3 g / L.

[0053] In some embodiments, a dosage of the sodium bisulfite added to the scouring liquor ranges from 0.5 to 1.5 g / L, such as 0.5-1 g / L and 1-1.5 g / L.

[0054] In some embodiments, a temperature of the scouring ranges from 110 to 120° C., such as 110-115° C., and 115-120° C.

[0055] In some embodiments, a scouring duration ranges from 30 to 50 min, such as 30-40 min and 40-50 min.

[0056] In some embodiments, the alkali weight reduction employs an aqueous solution of sodium hydroxide.

[0057] In some embodiments, a concentration of the aqueous solution of sodium hydroxide ranges from 10 to 15 g / L, such as 10-12 g / L and 12-15 g / L.

[0058] In some embodiments, a temperature of the alkali weight reduction ranges from 120 to 130° C., such as 120-125° C. and 125-130° C., preferably 125° C.

[0059] In some embodiments, the duration of the alkali weight reduction ranges from 35 to 45 min, such as 35-40 min and 40-45 min, preferably 40 min.

[0060] The alkali weight reduction utilizes the peeling effect of sodium hydroxide (caustic soda) on polyester to enhance softness and reduce pilling. Specifically, during alkali weight reduction, the polyester surface is corroded by the alkali, resulting in reduced fabric weight, finer fiber diameter, surface pitting, decreased fiber rigidity, elimination of polyester gloss, and increased inter-yarn spacing.

[0061] These effects collectively yield a softer hand feel, subdued luster, and improved moisture-wicking properties.

[0062] In some embodiments, the dyeing is performed only on the cellulosic yarns within the grey fabric.

[0063] In some embodiments, the dyeing process involves: adding water to the grey fabric, adjusting the pH, introducing a sulfur dye for heated dyeing, followed by adding sodium sulfate to maintain temperature during continued dyeing, and finally draining the liquor.

[0064] In some embodiments, a weight ratio of the grey fabric to the water ranges from 1:10 to 1:15, such as 1:10 to 1:12, and 1:12 to 1:15.

[0065] In some embodiments, the pH is adjusted to 5-6.

[0066] In some embodiments, a weight ratio of the sulfur dye to the grey fabric ranges from 1:0.8 to 1:1.2, such as 1:0.8 to 1:1.0 and 1:1.0 to 1:1.2.

[0067] In some embodiments, the sulfur dye is conventional and has a weak reducing property.

[0068] Specifically, the sulfur dye is a sulfur-containing dye synthesized from aromatic amines or phenolic compounds via fusion with sodium polysulfide or sulfur. These dyes require reduction to their leuco form using a reducing agent, preferably sodium sulfide, before application to the fibers. The leuco form of sulfur dyes exists as anions in the dye bath, exhibiting substantivity to cellulosic fibers. They adsorb onto the fiber surface, diffuse into the fiber interior, and oxidize to fix the color. This dyeing process selectively colors the cellulosic yarns in the fabric.

[0069] In some embodiments, the sulfur dye is added over 18-22 min, such as 18-20 min and 20-22 min, preferably 20 min. The sulfur dye is slowly introduced into the water after thorough mixing.

[0070] In some embodiments, the heated dyeing with a sulfur dye proceeds as follows: maintain at 20-30° C. for 8-12 minutes (preferably 25° C. for 10 minutes); gradually raise the temperature to 90-100° C. and hold for 8-12 minutes (preferably heat at 1-2° C. / min to 95° C. and hold for 10 minutes).

[0071] In some embodiments, a weight ratio of the sodium sulfate to the grey fabric ranges from 1:20 to 2:20, such as 1:20, 1.5:20, and 2:20.

[0072] During sodium sulfate addition, it is dissolved in water and introduced as a solution. Sodium sulfate enhances the uptake of the leuco sulfur dyes, improving color yield.

[0073] In some embodiments, a temperature-maintained dyeing duration ranges from 30 to 40 min, such as 30-35 min and 35-40 min,

[0074] In some embodiments, a temperature of the setting ranges from 180 to 190° C., such as 180-185° C., and 185-190° C.

[0075] In some embodiments, a speed of the setting ranges from 30 to 40 m / min, such as 30-35 m / min and 35-40 m / min.

[0076] In some embodiments, an overfeed during the setting ranges from 1% to 3%, such as 1% to 2%, and 2% to 3%.

[0077] In some embodiments, the duration of the setting ranges from 40 to 50 s, such as 40-45 s and 45-50 s.

[0078] Post-setting, the fabric achieves enhanced dimensional stability, resisting deformation even under humid and hot conditions during subsequent processing or garment use.

[0079] In some embodiments, the post-setting process includes fabric inspection and packaging.

[0080] In the third aspect, the present disclosure provides the use of a knitted twill cooling denim fabric for leggings in leggings.

[0081] The following examples illustrate specific implementations of the present disclosure. Those skilled in the art may readily extrapolate other advantages and operational efficiencies from the disclosed content. The present disclosure may also be adapted or applied through additional embodiments, with modifications or variations permissible within the inventive scope as defined by the claims.

[0082] In the following embodiments, unless otherwise specified, raw materials or processing techniques are conventional commercially available conventional products or standard industry practices.Embodiment 1

[0083] The knitting process was performed using a single-sided four-track circular knitting machine operated in a single-sided three-track knitting mode. A minimum stitch repeat unit was formed by 3 wale columns and six-position course rows. Multiple minimum stitch repeat units constructed a fabric surface to produce a grey fabric sample 1 #. Loop-forming stitch units were formed by the first wale with positions 2, 4, 5, and 6 of the 6-position course rows; float stitch units were formed by the first wale with positions 1 and 3 of the 6-position course rows; float stitch units were formed by the second wale with positions 1 and 5 of the 6-position course rows; loop-forming stitch units were formed by the second wale with positions 2, 3, 4, and 6 of the 6-position course rows; loop-forming stitch units were formed by the third wale with positions 1, 2, 4, and 6 of the 6-position course rows; and float stitch units were formed by the third wale with positions 3 and 5 of the 6-position course rows. Thereby the minimum stitch repeat unit was formed.

[0084] Two types of yarns were used for knitting. The filament yarns were used at positions 1, 3, and 5 of the six-position course rows; and cellulosic yarns and elastic fibers were knitted simultaneously at positions 2, 4, and 6 of the six-position course rows. The material of the filament yarns was polyester, the material of the cellulosic yarns was cotton, and the material of the elastic fibers was spandex. The ratio of filament yarns, cellulosic yarns, and elastic fibers was 1:1:1.

[0085] In the single-sided three-track knitting process, three-step needles were selected for the cylinder knitting needles, with the cylinder needle arrangement following an ABC cyclic pattern.

[0086] The post-finishing treatments of the grey fabric sample 1 #include: singeing, scouring, alkali weight reduction, dyeing, setting, fabric inspection, and packaging.

[0087] The singeing was performed on a gas singeing machine under the following parameters: double-sided singeing (one front / back pass), fabric speed controlled at 100 m / min, fabric-to-flame distance maintained at 0.9 cm, gasoline vaporization rate set to 23 kg / h, and vaporization temperature at 80° C.

[0088] The scouring was conducted at 115° C. for 40 minutes using a scouring liquor, including sodium hydroxide (4 g / L), TF-101H Special Oil Remover (1.3 g / L), a scouring agent (1.5 g / L, blend of phosphate ester surfactants and fatty alcohol polyoxyethylene ether), sodium silicate (2.3 g / L), and sodium bisulfite (1.0 g / L).

[0089] The alkali weight reduction is performed within a sodium hydroxide aqueous solution (12 g / L) at 125° C. for 40 minutes.

[0090] The dyeing was applied to the cellulosic yarns in grey fabric sample 1 #by adding water, adjusting the pH, adding sulfur dyes for heated dyeing, followed by adding sodium sulfate and maintaining temperature during continued dyeing, and finally draining the liquor. The grey fabric-to-water weight ratio was 1:12, with the pH adjusted to 5.5. Weakly reducible sulfur dyes were thoroughly mixed and slowly added into the water over 20 minutes, wherein a sulfur dye-to-grey fabric weight ratio of 1:1. The dye bath was initially held at 25° C. for 10 minutes, then gradually heated at 1.5° C. / min to 95° C. and maintained for 10 minutes. Sodium sulfate was subsequently added, and temperature-maintained dyeing continued for 35 minutes before draining the liquor. The sodium sulfate-to-grey fabric weight ratio was 1.5:20, with sodium sulfate dissolved in water and introduced as a solution of specified concentration.

[0091] The setting was performed at 185° C. for 45 seconds with a speed of 35 m / min, 2% overfeed. After fabric inspection and packaging, the fabric sample 1 #was obtained.Embodiment 2

[0092] The knitting process was performed using a single-sided four-track circular knitting machine operated in a single-sided three-track knitting mode. A minimum stitch repeat unit was formed by 3 wale columns and six-position course rows. Multiple minimum stitch repeat units constructed a fabric surface to produce a grey fabric sample 2 #. The minimum stitch repeat unit was formed in the same manner as described in Embodiment 1.

[0093] Two types of yarns were used for knitting. The filament yarns were used at positions 1, 3, and 5 of the six-position course rows; and cellulosic yarns and elastic fibers were knitted simultaneously at positions 2, 4, and 6 of the six-position course rows. The material of the filament yarns was nylon, the material of the cellulosic yarns was linen, and the material of the elastic fibers was polyolefin. The ratio of filament yarns, cellulosic yarns, and elastic fibers was 1:1:1.

[0094] In the single-sided three-track knitting process, three-step needles were selected for the cylinder knitting needles, with the cylinder needle arrangement following an ABC cyclic pattern.

[0095] The post-finishing treatments of the grey fabric sample 2 #include: singeing, scouring, alkali weight reduction, dyeing, setting, fabric inspection, and packaging.

[0096] The singeing was performed on a gas singeing machine under the following parameters: double-sided singeing (one front / back pass), fabric speed controlled at 110 m / min, fabric-to-flame distance maintained at 1.0 cm, gasoline vaporization rate set to 21 kg / h, and vaporization temperature at 90° C.

[0097] The scouring was conducted at 110° C. for 45 minutes using a scouring liquor, including sodium hydroxide (3 g / L), TF-101H Special Oil Remover (1.5 g / L), a scouring agent (1.3 g / L, blend of phosphate ester surfactants and fatty alcohol polyoxyethylene ether), sodium silicate (2.0 g / L), and sodium bisulfite (0.8 g / L).

[0098] The alkali weight reduction is performed within a sodium hydroxide aqueous solution (14 g / L) at 120° C. for 45 minutes.

[0099] The dyeing was applied to the cellulosic yarns in grey fabric sample 2 #by adding water, adjusting the pH, adding sulfur dyes for heated dyeing, followed by adding sodium sulfate and maintaining temperature during continued dyeing, and finally draining the liquor. The grey fabric-to-water weight ratio was 1:14, with the pH adjusted to 5.2. Weakly reducible sulfur dyes were thoroughly mixed and slowly added into the water over 22 minutes, wherein a sulfur dye-to-grey fabric weight ratio of 1:1.2. The dye bath was initially held at 27° C. for 9 minutes, then gradually heated at 1.0° C. / min to 92° C. and maintained for 12 minutes. Sodium sulfate was subsequently added, and temperature-maintained dyeing continued for 32 minutes before draining the liquor.

[0100] The setting was performed at 188° C. for 42 seconds with a speed of 32 m / min, 3% overfeed. After fabric inspection and packaging, the fabric sample 2 #was obtained.Embodiment 3

[0101] The knitting process was performed using a single-sided four-track circular knitting machine operated in a single-sided three-track knitting mode. A minimum stitch repeat unit was formed by 3 wale columns and six-position course rows. Multiple minimum stitch repeat units constructed a fabric surface to produce a grey fabric sample 3 #. The minimum stitch repeat unit was formed in the same manner as described in Embodiment 1.

[0102] Two types of yarns were used for knitting. The filament yarns were used at positions 1, 3, and 5 of the six-position course rows; and cellulosic yarns and elastic fibers were knitted simultaneously at positions 2, 4, and 6 of the six-position course rows. The material of the filament yarns was polyester, the material of the cellulosic yarns was cotton, and the material of the elastic fibers was spandex. The ratio of filament yarns, cellulosic yarns, and elastic fibers was 1:1:1.

[0103] In the single-sided three-track knitting process, three-step needles were selected for the cylinder knitting needles, with the cylinder needle arrangement following an ABC cyclic pattern.

[0104] The post-finishing treatments of the grey fabric sample 3 #include: singeing, scouring, alkali weight reduction, dyeing, setting, fabric inspection, and packaging.

[0105] The singeing was performed on a gas singeing machine under the following parameters: double-sided singeing (one front / back pass), fabric speed controlled at 90 m / min, fabric-to-flame distance maintained at 0.8 cm, gasoline vaporization rate set to 25 kg / h, and vaporization temperature at 100° C.

[0106] The scouring was conducted at 120° C. for 35 minutes using a scouring liquor, including sodium hydroxide (5 g / L), TF-101H Special Oil Remover (1 g / L), a scouring agent (1.8 g / L, blend of phosphate ester surfactants and fatty alcohol polyoxyethylene ether), sodium silicate (2.5 g / L), and sodium bisulfite (1.2 g / L).

[0107] The alkali weight reduction is performed within a sodium hydroxide aqueous solution (10 g / L) at 130° C. for 35 minutes.

[0108] The dyeing was applied to the cellulosic yarns in grey fabric sample 3 #by adding water, adjusting the pH, adding sulfur dyes for heated dyeing, followed by adding sodium sulfate and maintaining temperature during continued dyeing, and finally draining the liquor. The grey fabric-to-water weight ratio was 1:10, with the pH adjusted to 5.8. Weakly reducible sulfur dyes were thoroughly mixed and slowly added into the water over 18 minutes, wherein a sulfur dye-to-grey fabric weight ratio of 1:0.8. The dye bath was initially held at 23° C. for 11 minutes, then gradually heated at 2.0° C. / min to 98° C. and maintained for 8 minutes. Sodium sulfate was subsequently added, and temperature-maintained dyeing continued for 38 minutes before draining the liquor.

[0109] The setting was performed at 182° C. for 47 seconds with a speed of 38 m / min, 1% overfeed. After fabric inspection and packaging, the fabric sample 3 #was obtained.Test Example 1

[0110] The fabric samples 1 #to 3 #in Embodiments 1 to 3 have a structure as shown in FIG. 1 and FIG. 2.

[0111] As shown in FIG. 1 and FIG. 2, the float stitch units formed at position 1 of the 6-position course rows are offset longitudinally by one needle spacing from those formed at position 3, while the float stitch units formed at position 5 are offset longitudinally in the opposite direction from those at position 3. These float stitch units are covered by loop-forming stitch units from the subsequent course rows and remain on the fabric's backside, collectively creating a twill texture appearance. Specifically, the float stitch units at positions 1, 3, and 5 of the 6-position course rows are each covered by loop-forming stitch units from the subsequent course rows, and remain on the fabric's backside (i.e., the skin-contact surface).

[0112] Simultaneously, since the yarns at positions 1, 3, and 5 of the 6-position course rows are cooling-effect filament yarns, their exposed float stitch units on the fabric's backside directly contact the skin, enhancing the instantaneous cooling sensation during wear.

[0113] Furthermore, float stitch units require less yarn consumption compared to loop-forming stitch units. A higher proportion of loop-forming stitch units increases the fabric's lateral stretch capacity, whereas more float stitch units restrict lateral stretch. In this test example, the increased density of lateral float stitch units results in reduced lateral stretch performance. However, longitudinally, the loop-forming stitch units at position 2 of the 6-position course rows (covering the float stitch units from position 1) consume additional yarn length, while the interconnected loop-forming stitch units along the wales provide ample stretch space. This configuration ensures superior longitudinal stretch performance. For optimal garment functionality, the fabric is preferably cut transversely during apparel production (i.e., aligning the fabric's warp direction with the garment's lateral axis), thereby maximizing stretch performance and delivering exceptional wearing comfort.Test Example 2

[0114] A comparative analysis was conducted between the fabric sample 1 #from Embodiment 1 and a traditional woven stretch denim fabric. The woven denim fabric, which incorporates spandex-covered yarns for elasticity, was selected to match the thickness of Fabric Sample 1 #. Garments were cut transversely from both fabrics, and their stretch performance was tested, with specific results detailed in Table 2 below.TABLE 2The fabric sample 1#The traditional wovenTest results of thestretch denim fabricgarments after(Referring to A&FItemwashingultra-fit jeans)PhysicalSpecification340 gsm450 gsmpropertyComponent48% of polyester6% of polyester42% of cotton93% of cotton10% of spandex1% of spandexElongationWeft direction15040LTD03Warp direction7510(%)RecoveryWeft direction90N / A(%)Warp direction92N / A

[0115] As shown in Table 2, traditional denim fabrics exhibit a tightly woven texture, substantial weight, vibrant coloration, and distinct weave patterns after anti-shrinkage finishing. In contrast, the knitted denim-style fabric (e.g., fabric sample 1 #from Embodiment 1) achieves comparable visual aesthetics and woven-like texture through optimized yarn selection, structural design, patterning, and post-finishing treatments, while offering superior softness and comfort. Furthermore, at equivalent thickness, fabric sample 1 #is 24% lighter in grammage than the woven denim, demonstrating exceptional lightweight properties. In terms of elasticity, the weft-wise stretch of fabric sample 1 #in garment form is 3.75 times that of woven denim, while the warp-wise stretch reaches 7.5 times that of woven denim. Additionally, fabric sample 1 #maintains a recovery rate exceeding 90%, highlighting its outstanding stretch performance. These results confirm that fabric sample 1 #outperforms traditional woven stretch denim in both elasticity and lightweight characteristics.Test Example 3

[0116] The fabric sample 1 #in Embodiment 1 was subjected to a contact cool feeling test. That is, a cool-feeling property of the fabric sample 1 #was evaluated based on a contact cool feeling coefficient Q-max (J / (cm2·s)), measured in accordance with the Chinese national standard GB / T 35263-2017 “Textiles-Testing and Evaluation for Cool Feeling in Contact Instant”. As per GB / T 35263-2017, a fabric is deemed to exhibit the contact cool feeling if its coefficient Q-max (J / (cm2·s)) is greater than or equal to 0.15. The test parameters included a sample platform material of polystyrene foam, an instrument model of Roaches Q-Max, ambient conditions of 20.1° C. temperature and 65.0% humidity, a hot plate temperature maintained at 35.0±0.5° C., a cold plate temperature set to 20.0±0.5° C., and the sample contact surface designated as the skin-facing side. Specific test results for the contact cool feeling coefficient are shown in Table 3.TABLE 3Contact cool feelingPre-washPost-30-wash-cyclecoefficient (J / (cm2 · s))fabric sample 1#fabric sample 1#10.210.2220.220.2130.230.2240.230.2150.230.22Average value0.220.22

[0117] As indicated in Table 3, all five Q-max measurements of fabric sample 1 #, as well as their average value, exceeded 0.15 J / (cm2·s), confirming compliance with GB / T 35263-2017 and validating its cool-feeling properties. This cool feeling effect is achieved by maximizing the skin-contact area of the fabric's cooling-functional side, which combines the loop-forming characteristics of the knitted structure with inherently cooling filament fibers in the yarn. Additionally, post-30-wash-cycle Q-max test results and their average, as shown in Table 3, remained above the required threshold of 0.15 J / (cm2·s), demonstrating permanent cooling efficacy. This addresses the common issue of water wash durability in fabrics relying on cooling agent finishes, where cooling effects typically degrade after repeated laundering.Test Example 4

[0118] The fabric sample 1 #in Embodiment 1 was subjected to a moisture permeability test. This test simulates the fabric's ability to transfer moisture vapor (generated by the human body under varying activity levels) to the external environment, ensuring breathability and preventing discomfort during wear. Moisture permeability refers to the mass or efficiency of water vapor transmission through the fabric, reflecting both the vapor emitted by the body during movement and the influence of external environmental humidity. The test method involves sealing a fabric specimen over a moisture permeability cup containing distilled water at a specified temperature. The assembly is placed in a sealed environment with controlled temperature and humidity. Under maintained temperature-humidity conditions on both fabric surfaces, the mass of water vapor vertically transmitted per unit area over a defined period is measured in grams per square meter per hour [g / (m2·h)]. Specific test results are shown in Table 4.TABLE 4StandardTest valueSamplenumberIndex nameTest dataUnitThe fabric sample 1#GB / Moisture1311.5g / (m2 ·Test results of theT12704.2permeability24 h)garments after beingwashedThe traditional wovenGB / Moisture633.8g / (m2 ·stretch denim fabricT12704.2permeability24 h)Referring to A&Fultra-fit jeans

[0119] As shown in Table 4, the moisture permeability rate of fabric sample 1 #exceeds twice that of traditional woven stretch denim fabric, demonstrating that fabric sample 1 #provides significantly reduced stuffiness and superior comfort compared to traditional woven stretch denim during wear.

[0120] The above descriptions are merely preferred embodiments of the present disclosure and shall not be construed as limitations to the present disclosure. It should be noted that for those skilled in the art, several improvements and supplements may be made without departing from the technical solution of the present disclosure, which shall also be regarded as falling within the protection scope of the present invention. Those skilled in the art may utilize the technical content disclosed above to make minor alterations, modifications, and equivalent changes in practice without departing from the scope of the present invention, which shall be deemed as equivalent embodiments of the present invention. Meanwhile, any equivalent alterations, modifications, and changes made to the aforementioned embodiments based on the essential technology of the present invention shall still belong to the scope of the technical solutions of the present invention.

Claims

1. A knitted twill cooling denim fabric, wherein the fabric adopts a single-sided three-track knitted structure comprising multiple minimum stitch repeat units, and each of the minimum stitch repeat units comprises three wale columns and six courses;a structural unit formed by a first wale and the six courses is configured as follows: loop-forming stitch units are formed at positions 2, 4, 5, and 6 of the six courses; and float stitch units are formed at positions 1 and 3 of the six courses;a structural unit formed by a second wale and the six courses is configured as follows: float stitch units are formed at positions 1 and 5 of the six courses; and loop-forming stitch units are formed at positions 2, 3, 4, and 6 of the six courses; anda structural unit formed by a third wale and the six courses is configured as follows: loop-forming stitch units are formed at positions 1, 2, 4, and 6 of the six courses; and float stitch units are formed at positions 3 and 5 of the six courses.

2. A method for preparing a knitted twill cooling denim fabric, comprising:knitting with yarns to form a grey fabric, wherein a knitting process forms stitch repeat unit comprising three wales and six courses, and a plurality of the stitch repeat units are sequentially arranged to form a fabric surface; andsubjecting the grey fabric to post-finishing treatments to obtain the knitted twill cooling denim fabric;wherein the three wales of the stitch repeat unit comprise a first wale, a second wale, and a third wale, and the six courses comprise a first course, a second course, a third course, a fourth course, a fifth course, and a sixth course;wherein the stitch repeat unit comprises: loop-forming stitch units in the first wale, formed at the second course, the fourth course, the fifth course, and the sixth course; float stitch units in the first wale, formed at the first course and the third course;float stitch units in the second wale, formed at the first course and the fifth course; loop-forming stitch units in the second wale, formed at the second course, the third course, the fourth course, and the sixth course; loop-forming stitch units in the third wale, formed at the first course, the second course, the fourth course, and the sixth course; and float stitch units in the third wale, formed at the third course and the fifth course;wherein the float stitch units in the first, third, and fifth courses of the stitch repeat unit are arranged on a skin-contact surface of the grey fabric, wherein the float stitch units on the skin-contact surface extending in a course direction form a heat-conducting path and create a twill texture appearance;wherein two types of yarns are used for knitting, a first type comprising filament yarns is used in the first, third, and fifth courses, and a second type comprising cellulosic yarns and elastic fibers knitted together is used in the second, fourth, and sixth courses;wherein a material of the filament yarns comprises at least one of polyester and nylon.

3. (canceled)4. The method of claim 2, wherein the second yarns comprise one or more of the following:A2) a material of the cellulosic yarns comprises but is not limited to cotton, linen, viscose, and lyocell; andA3) a material of the elastic fibers comprises but is not limited to spandex and polyolefin.

5. (canceled)6. (canceled)7. The method of claim 1, wherein the filament yarns are polyester filament yarns, and the post-finishing treatments comprise: singeing, scouring, alkali weight reduction, dyeing, and setting of the grey fabric.

8. The method of claim 7, wherein the post-finishing treatments comprise one or more of the following:B1) the singeing parameters are as follows: a front and a back of the grey fabric passing a flame to singe both surfaces of the grey fabric; a moving speed of the grey fabric when being singed controlled at 80-120 m / min; a distance between the fabric and the flame maintained at 0.8-1.0 cm; gasoline vaporization rate set to 20-25 kg / h; and vaporization temperature ≥80° C.;B2) the scouring is performed by using caustic soda, a degreasing agent, a scouring agent, and scouring auxiliaries;B3) a temperature of the scouring ranges from 110 to 120° C.;B4) a duration of the scouring ranges from 30 to 50 min;B5) the alkali weight reduction employs an aqueous solution of sodium hydroxide;B6) a temperature of the alkali weight reduction ranges from 120 to 130° C.;B7) a duration of the alkali weight reduction ranges from 35 to 45 min;B8) the dyeing is performed only on the cellulosic yarns within the grey fabric;B9) the dyeing process involves: adding water to the grey fabric, adjusting the pH, introducing a sulfur dye for heated dyeing, followed by adding sodium sulfate and maintaining temperature during continued dyeing, and finally draining the liquor;B10) a temperature of the setting ranges from 180 to 190° C.;B11) a speed of the setting ranges from 30 to 40 m / min;B12) an overfeed of the setting ranges from 1% to 3%;B13) a duration of the setting ranges from 40 to 50 s; andB14) a post-setting process comprises fabric inspection and packaging.

9. The method of claim 8, wherein the post-finishing treatments comprise B2), B5) and B9), and the method further comprises one or more of the following:B21) in B2), a dosage of the caustic soda added to a scouring liquor ranges from 3 to 5 g / L;B22) in B2), a dosage of the degreasing agent added to the scouring liquor ranges from 1 to 1.5 g / L;B23) in B2), a dosage of the scouring agent added to the scouring liquor ranges from 1 to 2 g / L;B24) in B2), the scouring auxiliaries comprise sodium silicate and sodium bisulfite;wherein a dosage of the sodium silicate added to the scouring liquor ranges from 1.5 to 3 g / L; and / or, a dosage of the sodium bisulfite added to the scouring liquor ranges from 0.5 to 1.5 g / L;B51) in B5), a concentration of the aqueous solution of sodium hydroxide ranges from 10 to 15 g / L;B91) in B9), a weight ratio of the grey fabric to the water ranges from 1:10 to 1:15;B92) in B9), the pH is adjusted to 5-6;B93) in B9), a weight ratio of the sulfur dye to the grey fabric ranges from 1:0.8 to 1:1.2;B94) in B9), the sulfur dye is added over 18 to 22 min;B95) in B9), the heated dyeing with a sulfur dye proceeds as follows: maintain at 20-30° C. for 8-12 minutes; gradually raise the temperature to 90-100° C. and hold for 8-12 minutes;B96) in B9), a weight ratio of the sodium sulfate to the grey fabric ranges from 1:20 to 2:20; andB97) in B9), a temperature-maintained dyeing duration ranges from 30 to 40 min.

10. A method for preparing leggings, comprising stitching the knitted twill cooling denim fabric of claim 1 into leggings.

11. A method for preparing a knitted twill cooling denim fabric, comprising:knitting with yarns to form a grey fabric, wherein a knitting process forms a stitch repeat unit comprising three wales and six courses, wherein cooling-effect filament yarns are knitted to form float stitch units at first, third, and fifth courses of the stitch repeat unit, wherein the float stitch units are staggered by one needle position in a wale direction and arranged on a skin-contact surface of the grey fabric;knitting a plurality of the stitch repeat units to form the grey fabric, wherein the float stitch units on the skin-contact surface extending in a course direction form a heat-conducting path and create a twill texture appearance; andsubjecting the grey fabric to post-finishing treatments to obtain the knitted twill cooling denim fabric;wherein the cooling-effect filament yarns comprise polyester and nylon.

12. The method according to claim 11, wherein two types of yarns are used for knitting, a first type comprising the cooling-effect filament yarns used in the first, third, and fifth courses, and a second type comprising cellulosic yarns and elastic fibers knitted together used in second, fourth, and sixth courses.

13. The method according to claim 12, wherein the cooling-effect filament yarns are selected as the polyester filament yarns, and the post-finishing treatments comprise: singeing, scouring, alkali weight reduction, dyeing, and setting of the grey fabric.

14. The method of claim 13, wherein the post-finishing treatments comprise one or more of the following:B1) the singeing parameters are as follows: a front and a back of the grey fabric passing a flame to singe both surfaces of the grey fabric; a moving speed of the grey fabric when being singed controlled at 80-120 m / min; a distance between the fabric and the flame maintained at 0.8-1.0 cm; gasoline vaporization rate set to 20-25 kg / h; andvaporization temperature ≥80° C.;B2) the scouring is performed by using caustic soda, a degreasing agent, a scouring agent, and scouring auxiliaries;B3) a temperature of the scouring ranges from 110 to 120° C.;B4) a duration of the scouring ranges from 30 to 50 min;B5) the alkali weight reduction employs an aqueous solution of sodium hydroxide;B6) a temperature of the alkali weight reduction ranges from 120 to 130° C.;B7) a duration of the alkali weight reduction ranges from 35 to 45 min;B8) the dyeing is performed only on the cellulosic yarns within the grey fabric;B9) the dyeing process involves: adding water to the grey fabric, adjusting the pH, introducing a sulfur dye for heated dyeing, followed by adding sodium sulfate and maintaining temperature during continued dyeing, and finally draining the liquor;B10) a temperature of the setting ranges from 180 to 190° C.;B11) a speed of the setting ranges from 30 to 40 m / min;B12) an overfeed of the setting ranges from 1% to 3%;B13) a duration of the setting ranges from 40 to 50 s; andB14) a post-setting process comprises fabric inspection and packaging.

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