A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn

Abstract

This invention relates to the field of textile manufacturing, and more particularly to a method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn. The method involves forming a hot-melt adhesive layer on the surface of a core yarn, then covering the core yarn with a sheath yarn. Heating softens the hot-melt adhesive, followed by cooling to solidify it, resulting in the low-twist, high-strength, and highly breathable mechanically covered yarn. The process of forming the hot-melt adhesive layer on the core yarn surface involves transferring molten hot-melt adhesive onto the core yarn via a glue-applying roller, then passing the core yarn sequentially through a twister, a untwist device, and a scraper, followed by natural cooling until the hot-melt adhesive on the core yarn solidifies. This invention improves the breaking strength and breathability of the covered yarn, avoids problems such as increased sheath yarn twist and the stiff hand feel caused by full glue coating of the core yarn, and reduces covering costs. It has significant application prospects in the field of high-performance textiles.

Description

Technical Field

[0001] This invention relates to the field of textile manufacturing, and in particular to a method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn. Background Technology

[0002] Covered yarn is a composite of two or more fibers, which can compensate for the shortcomings of single-component fibers and give full play to the advantages of composite fibers. Therefore, it is of great significance to study the preparation method of covered yarn. At present, the main preparation methods of covered yarn are hollow spindle covering method and air covering method. Among them, the basic process of hollow spindle covering method is that the core yarn enters the hollow spindle at a certain speed, while the outer covering yarn is unwound from the hollow spindle yarn tube and twisted on the core yarn to achieve the function of covering and fixing.

[0003] In the current process of preparing covered yarn, the magnitude of the covering twist has a significant impact on yarn performance. Increasing the covering twist is often used to improve yarn breaking strength. However, increasing the covering twist can lead to a stiffer yarn feel, reduced elasticity, and poor drape in woven fabrics. Furthermore, some applications require covered yarns with high strength and low twist, such as yarns for napped fabrics and cold-weather fabrics. Both require yarns that meet the strength requirements under high-speed weaving. The former requires low covering twist to facilitate napping, while the latter requires low covering twist to increase the gaps between fibers, thereby increasing the amount of still air. In addition, existing technologies also use hot melt adhesives to bond the core yarn and the outer yarn, but the adhesive application method is mainly impregnation. This coating method reduces the air permeability of the covered yarn and limits its softness.

[0004] For example, patent application CN117306040A discloses a nylon-spandex covered yarn, an ultra-soft, ultra-elastic, high-coated drag-reducing fabric, and its preparation method. It uses ultra-fine denier spandex as the core and high-twist nylon as the covering. By twisting multiple ultra-fine denier spandex filaments together and covering them with high-twist nylon, the prepared covered yarn has a soft hand feel, increased density, and improved breaking strength. However, its high twist of the outer yarn results in a heavy machine load and high covering cost.

[0005] For example, patent application CN118186647A discloses a method for preparing composite core-spun yarn. This method involves impregnating the core yarn with a hot melt adhesive, then stretching and thinning the core yarn coated with the melt adhesive layer. The resulting core-spun yarn exhibits good strength and abrasion resistance. However, this impregnation method results in excessive adhesive coating, which reduces the breathability and softness of the composite core-spun yarn.

[0006] Therefore, given the shortcomings of existing technologies in achieving low twist, high breaking strength, and high air permeability in coated yarn, it is necessary to develop a new method for preparing coated yarn. Summary of the Invention

[0007] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide a method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn involves forming a hot melt adhesive layer on the surface of a core yarn, then covering the core yarn with a sheath yarn, heating to soften the hot melt adhesive, and then cooling to solidify the hot melt adhesive, thus obtaining the low-twist, high-strength, and highly breathable mechanically covered yarn. The process of forming a hot melt adhesive layer on the surface of the core yarn is as follows: molten hot melt adhesive is transferred to the core yarn through a glue-applying roller, and the core yarn is then passed sequentially through a twister, a untwister, and a scraper (the scraper's function is to make the hot melt adhesive on the core yarn surface thin and uniform), and then naturally cooled until the hot melt adhesive on the core yarn solidifies. The glue-applying roller has an uneven circumference, is partially immersed in the molten hot melt adhesive, and rotates uniformly around its own central axis. The molten hot melt adhesive is located in a heating tank. The core yarn has a twist of 0 before passing through the twister and a twist of 0 after passing through the untwister.

[0010] The purpose of twisting in this invention is to control the helical movement of the core yarn, so that the adhesive dots are evenly distributed and initially fixed. The purpose of untwisting is to eliminate the helical twist of the core yarn, but retain the uniform adhesive dot structure formed during the twisting process. Because the adhesive application method of this invention is roller coating, the amount of adhesive applied is small, and the product has high air permeability. Because this invention can achieve uniform distribution of adhesive dots, it can enable the covered yarn to have the same breaking strength as high-coverage-twist yarn even with a low-coverage-twist yarn.

[0011] As a preferred technical solution:

[0012] As described above, in the preparation method of a low-twist, high-strength, and highly breathable mechanically covered yarn, the ratio of the fineness of the core yarn to the twist of the core yarn after passing through the twister (that is, the ratio of the fineness of the uncoated core yarn to the twist of the core yarn after passing through the twister) is 1D:14-15 twists / m. This makes the bonding point distance uniform and the breaking strength of the covered yarn higher.

[0013] The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn as described above involves a circumferential surface roughness of 1.5 μm for the feeding roller, a diameter of 300 mm for the feeding roller, a covering angle of 70° for the core yarn on the feeding roller (the encirclement angle formed by the core yarn on the feeding roller when the core yarn contacts the surface of the feeding roller), a running time of 1 s for the core yarn between the feeding roller and the twister, a running time of 2.5 s for the core yarn between the twister and the untwisting device, a running time of 1.5 s for the core yarn between the untwisting device and the scraper, a rotational speed of 100 r / min for the feeding roller, and a uniform speed of 95 m / min for the core yarn during the formation of a hot melt adhesive layer on the surface of the core yarn.

[0014] The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn as described above uses PES (polyester) hot melt adhesive or PA (polyamide) hot melt adhesive as the hot melt adhesive.

[0015] In the preparation method of the low-twist, high-strength, and highly breathable mechanically covered yarn described above, the thickness of the hot melt adhesive layer is 7 μm.

[0016] The preparation method of a low-twist, high-strength, and highly breathable mechanically covered yarn as described above involves the following process: the core yarn is guided by the first yarn guide of the covering machine, enters the central tube of the hollow spindle from the bottom end, and is drawn out from the top end. During this process, the outer yarn is unwound as the hollow spindle rotates. When the outer yarn and the core yarn reach the confluence guide hook, the outer yarn is spirally wrapped onto the core yarn. The rotation speeds of the hollow spindle and the glue roller do not need to be matched because they are not part of an integrated machine.

[0017] The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn as described above has a covering twist of 300 twists / m, a spindle rotation speed of 15000 r / min, and a core yarn draft ratio of 3.2.

[0018] The preparation method of a low-twist, high-strength, and highly breathable mechanically covered yarn as described above, wherein heating to soften the hot melt adhesive and then cooling to solidify the hot melt adhesive refers to controlling the core yarn of the surface-covered yarn to pass sequentially through a hot air zone (during which the hot melt adhesive is heated and softens, bonding the fibers on the surface of the yarn) and a cold air zone.

[0019] As described above, in the preparation method of a low-twist, high-strength, and highly breathable mechanically coated yarn, the temperature of the hot air zone is 5-10°C higher than the softening temperature of the hot melt adhesive. The length of the hot air zone is 10cm, and the wind speed is 1m / s. This allows the hot melt adhesive on the surface of the core yarn to be heated and softened rapidly. The temperature of the cold air zone is 20°C, the length of the cold air zone is 20cm, and the wind speed is 0.5m / s. This ensures that the hot melt adhesive is completely cooled and cured, and that the adhesive film is stable, reducing defects.

[0020] The preparation method of the low-twist, high-strength, and highly breathable mechanically covered yarn described above, wherein the core yarn is spandex yarn with a specification of 20-40D / 3F; the outer yarn is polyester DTY yarn with a specification of 75-150D / 72-144F, or the outer yarn is nylon DTY yarn with a specification of 30-70D / 24F.

[0021] As described above, the preparation method of a low-twist, high-strength, and highly breathable mechanically covered yarn has a cross-section of either triangular or trefoil shape in the monofilament of the yarn. Because the irregular cross-section of the yarn is not circular, its surface has a groove structure. The presence of these grooves creates a strong capillary effect, enabling the fiber to quickly transport and diffuse water, remove moisture and sweat from the skin surface, and improve the moisture absorption and wicking properties of the fiber.

[0022] The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn as described above has the following characteristics: the linear density of the low-twist, high-strength, and highly breathable mechanically covered yarn is 50.3-194.5 dtex, the breaking strength is 3.0-4.6 cN / dtex, the breaking elongation is 22.7-41.2%, the wicking height is 8.8-65.8 mm, and the air permeability of the fabric made from the low-twist, high-strength, and highly breathable mechanically covered yarn is 153-515 mm / s.

[0023] The present invention also provides a method for forming a hot melt adhesive layer on the surface of yarn. After transferring molten hot melt adhesive to the yarn through a glue-applying roller, the yarn is passed sequentially through a twister, a untwisting device, and a scraper, and then naturally cooled until the hot melt adhesive on the yarn solidifies. The glue-applying roller has an uneven circumferential surface, is half-immersed in the molten hot melt adhesive, and rotates at a uniform speed around its own central axis. The molten hot melt adhesive is located in a heating tank. The yarn has zero twist before passing through the twister and zero twist after passing through the untwisting device.

[0024] As a preferred technical solution:

[0025] In the method described above for forming a hot melt adhesive layer on the surface of yarn, the ratio of the yarn fineness to the yarn twist after passing through the twister is 1D: 14-15 twists / m.

[0026] In the method described above for forming a hot melt adhesive layer on the surface of yarn, the roughness of the circumferential surface of the glue-feeding roller is 1.5 μm, the diameter of the glue-feeding roller is 300 mm, the wrap angle of the yarn on the glue-feeding roller is 70°, the running time of the yarn between the glue-feeding roller and the twister is 1 s, the running time of the yarn between the twister and the untwisting device is 2.5 s, and the running time of the yarn between the untwisting device and the scraper is 1.5 s.

[0027] The method described above for forming a hot melt adhesive layer on the surface of a yarn, wherein the hot melt adhesive is a PES hot melt adhesive or a PA hot melt adhesive.

[0028] The method described above for forming a hot melt adhesive layer on the surface of a yarn has a thickness of 7 μm.

[0029] The method described above for forming a hot melt adhesive layer on the surface of a yarn, wherein the yarn is spandex filament with a specification of 20-40D / 3F.

[0030] Beneficial effects:

[0031] (1) The present invention applies glue to the core yarn by applying glue to the rubber roller, and then passes it through a twister and a detwisting device. The core yarn has a twist of 0 before passing through the twister and a twist of 0 after passing through the detwisting device. This makes the spun covered yarn still tightly wrapped under the low twist condition of the outer yarn, which not only improves the breaking strength of the covered yarn, but also has the soft hand feel of the covered yarn under the low twist condition of the outer yarn. This avoids the problem of the covered yarn feeling hard and the drape of the woven fabric being poor due to the increased twist of the outer yarn. At the same time, it also improves the air permeability of the covered yarn.

[0032] (2) The present invention reduces the coating twist. Under the condition of low coating twist, the core yarn is subjected to less pressure and the load of the coating machine is small, which is conducive to reducing the coating cost and also conducive to the core yarn maintaining a stable state in the hollow spindle, reducing the possibility of core deviation and the defect rate. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the equipment structure used for gluing, twisting, and untwisting in this invention (the arrows in the diagram represent the running direction of the core yarn).

[0034] Figure 2 This is a schematic diagram of the coating machine equipment used in the present invention (the arrows in the diagram represent the running direction of the equipment).

[0035] Figure 3 A schematic diagram of the equipment structure used for impregnation in Comparative Example 2 (the arrows in the diagram represent the running direction of the core yarn).

[0036] In the diagram, 101-core yarn, 102-hot melt adhesive, 103-scraper, 201-first yarn guide roller, 202-first yarn guide, 203-hollow spindle, 204-leather yarn, 205-converging yarn guide hook, 206-hot air zone, 207-cold air zone, 208-lateral yarn guide, 209-winding roller, 210-second yarn guide roller, 211-yarn guide rod, 301-guide roller, 302-first pressure roller, 303-second pressure roller, 304-glue roller, 305-third pressure roller, 306-twisting device, 307-untwisting device. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0038] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0039] (1) Linear density: According to GB / T 14343-2008 "Test method for linear density of chemical fiber filament", the test was conducted using a yarn length measuring instrument and an electronic balance.

[0040] (2) Breaking strength: The test was conducted in accordance with GB / T 3916-2013 "Determination of breaking strength and elongation at break of single yarn in packaged textiles" and FZ / T 50006-2013 "Test method for tensile properties of spandex yarn". The YG023B fully automatic single yarn strength tester was used. The test was repeated 10 times under the test conditions of 50mm spacing, 500mm / min tensile speed and 0.5cN / tex pretension. The average value was calculated after removing outliers from the original data.

[0041] (3) Elongation at break: The test was conducted in accordance with GB / T 3916-2013 "Determination of breaking strength and elongation at break of single yarn in packaged textiles" and FZ / T 50006-2013 "Test method for tensile properties of spandex yarn". The YG023B fully automatic single yarn strength tester was used. The test was repeated 10 times under the test conditions of 50mm spacing, 500mm / min tensile speed and 0.5cN / tex pretension. The average value was calculated after removing outliers from the original data.

[0042] (4) Cumulus height: Tested according to FZ / T1071-2008 "Textiles Capillary Effect Test Method".

[0043] (5) Air permeability: According to GB / T 5453-1997 "Determination of air permeability of textile fabrics", the yarns were woven into plain weave fabrics with a fabric weight of 130 g / m². 2 The air permeability of the fabric was tested using a YG416D digital fabric air permeability meter. The pressure drop across the fabric was 100 Pa, and the sample area was slightly larger than 20 cm². 2 Select appropriate circular vent holes at different locations on each sample, repeat the measurement at least 10 times, and take the average value of the results.

[0044] Example 1

[0045] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn, employing methods such as... Figure 1 and Figure 2 The specific steps for the device shown are as follows:

[0046] (1) Prepare raw materials;

[0047] Hot melt adhesive: PES hot melt adhesive masterbatch, manufactured by Suzhou Huiyang Adhesive Products Co., Ltd.

[0048] Core yarn: Spandex yarn, specification 40D / 3F;

[0049] Leather yarn: Polyester DTY yarn, specification is 150D / 144F, the cross-section of the single filament is triangular;

[0050] (2) A hot melt adhesive layer is formed on the surface of the core yarn;

[0051] Adopting such Figure 1 The device shown places hot melt adhesive 102 in a heating tank and heats it to 140°C to melt the hot melt adhesive 102. First, the core yarn 101 passes sequentially through the upper edge of the guide roller 301, the lower edge of the first pressure roller 302, the lower edge of the second pressure roller 303, and then through the upper edge of the glue-feeding roller 304. The molten hot melt adhesive 102 is transferred to the core yarn 101 through the glue-feeding roller 304. Then, the core yarn 101 passes through the lower edge of the third pressure roller 305, and then sequentially through the twister 306, the untwisting device 307, and the scraper 103. Finally, the hot melt adhesive 102 placed on the core yarn 101 at room temperature (20-25°C) solidifies. The thickness of the hot melt adhesive layer on the surface of the core yarn 101 is 7μm.

[0052] The peripheral surface of the glue-feeding roller 304 is uneven, with a roughness of 1.5 μm. The diameter of the glue-feeding roller 304 is 300 mm. The glue-feeding roller 304 is half-immersed in the molten hot melt adhesive 102 and rotates uniformly around its own central axis at a speed of 100 r / min. The wrapping angle of the core yarn 101 on the glue-feeding roller 304 is 70°.

[0053] The core yarn 101 has a twist of 0 before passing through the twister 306, and the core yarn 101 has a twist of 0 after passing through the untwisting device 307;

[0054] The ratio of the fineness of the core yarn 101 before passing through the twister 306 to the twist of the core yarn 101 after passing through the twister 306 is 1D:15 twists / m;

[0055] The core yarn 101 travels for 1 second between the feeding roller 304 and the twister 306, 2.5 seconds between the twister 306 and the untwisting device 307, and 1.5 seconds between the untwisting device 307 and the scraper 103. The core yarn travels at a constant speed of 95 m / min.

[0056] (3) Wrap the outer yarn over the core yarn;

[0057] Adopting such Figure 2The device shown in the figure guides the core yarn 101 obtained in step (2) into the center tube of the hollow spindle 203 from the bottom and out from the top under the guidance of the first yarn guide roller 201 and the yarn guide 202 of the covering machine. During this process, the leather yarn 204 is unwound as the hollow spindle 203 rotates. When the leather yarn 204 and the core yarn 101 reach the confluence guide hook 205, the leather yarn 204 is wrapped around the core yarn 101 in a spiral manner to obtain the core yarn 101 with the surface covered by the leather yarn 204.

[0058] The wrapping twist is 300 twists / m, the rotation speed of the hollow spindle 203 is 15000 r / min, and the draft ratio of the core yarn 101 is 3.2.

[0059] (4) Heat the hot melt adhesive to soften it, then cool it down to solidify it;

[0060] Adopting such Figure 2 The device shown takes the core yarn 101 of the surface-coated yarn 204 obtained in step (3) through the second yarn guide roller 210 and the yarn guide rod 211, and controls the core yarn 101 of the surface-coated yarn 204 to pass through the hot air area 206 and the cold air area 207 in sequence, so as to obtain a low-twist, high-strength and high-breathability mechanically coated yarn.

[0061] The temperature of hot air zone 206 is 115℃, the length of hot air zone 206 is 10cm, and the wind speed of hot air zone 206 is 1m / s.

[0062] The temperature of cold air zone 207 is 20℃, the length of cold air zone 207 is 20cm, and the wind speed of cold air zone 207 is 0.5m / s;

[0063] (5) Winding;

[0064] Adopting such Figure 2 The device shown has a low-twist, high-strength, and highly breathable mechanically covered yarn wound onto the bobbin driven by the friction drive of the winding roller 209 as the traverse yarn guide 208 swings back and forth, ready for use.

[0065] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 193.9 dtex, a breaking strength of 3.5 cN / dtex, a breaking elongation of 33.7%, and a wicking height of 10.2 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 174 mm / s.

[0066] Comparative Example 1

[0067] A method for preparing mechanically covered yarn differs from Example 1 only in that the twister and untwisting device are omitted in step (2).

[0068] The final mechanically covered yarn has a linear density of 193.0 dtex, a breaking strength of 2.7 cN / dtex, a breaking elongation of 21.0%, a wicking height of 8.2 mm, and an air permeability of 146 mm / s for the fabric made from the mechanically covered yarn.

[0069] Compared with Example 1, the linear density of the mechanically covered yarn prepared in Comparative Example 1 did not change significantly, but the breaking strength decreased by 22.9%, the breaking elongation decreased by 37.7%, the wicking height decreased by 19.6%, and the air permeability of the fabric decreased by 16.1%. This is because: In Example 1, during the twisting process, the initially attached discrete adhesive dots, along with the fiber twisting, penetrated into the fiber gaps, and the originally flat block adhesive dots were dispersed, eventually forming adhesive dots that were more evenly distributed along the core yarn axis. The core yarn of the prepared covered yarn was more evenly stressed, the outer yarn adhered more tightly to the core yarn, and the breaking strength and breaking elongation of the covered yarn were higher; the twisting-untwisting process formed relatively continuous and uniformly sized capillaries inside the covered yarn, resulting in less resistance to moisture climbing and a higher wicking height; the twisting-untwisting process made the gaps between the yarns of the covered yarn more regular and the connectivity better, resulting in higher air permeability of the fabric. In Comparative Example 1, after omitting twisting and untwisting, the local fibers of the covered yarn will slip rapidly during the stretching process and then break quickly, resulting in a decrease in breaking strength and breaking elongation. The covered yarn cannot form relatively continuous and uniform capillaries, and the wicking height is reduced. The regularity of the gaps between the yarns is reduced, the connectivity is worsened, and the air permeability of the fabric is reduced.

[0070] Comparative Example 2

[0071] A method for preparing mechanically coated yarn differs from Example 1 only in that: step (2) uses an impregnation method to form a hot melt adhesive layer on the surface of the core yarn, such as... Figure 3 As shown, the specific process is as follows:

[0072] Hot melt adhesive 102 is placed in a heating tank and heated to 140°C to melt it. Core yarn 101 is then introduced into the heating tank at a speed of 5 cm / s through guide roller 301, so that core yarn 101 is completely immersed in hot melt adhesive 102 and remains there for 10 seconds. After the surface of core yarn 101 is coated with hot melt adhesive 102, the core yarn 101 with the hot melt adhesive 102 coating is passed through scraper 103 to make the hot melt adhesive 102 on the surface of core yarn 101 evenly distributed. Then, the hot melt adhesive 102 on the core yarn 101 solidifies at room temperature (20-25°C). The thickness of the hot melt adhesive 102 layer on the surface of core yarn 101 is 7 μm.

[0073] The final mechanically covered yarn has a linear density of 195.2 dtex, a breaking strength of 2.9 cN / dtex, a breaking elongation of 20.2%, a wicking height of 7.4 mm, and an air permeability of 135 mm / s for the fabric made from the mechanically covered yarn.

[0074] Compared with Example 1, the linear density of the mechanically covered yarn prepared in Comparative Example 2 did not change significantly, but the breaking strength decreased by 17.1%. The breaking elongation decreased by 40.1%, the wicking height decreased by 27.5%, and the air permeability of the fabric decreased by 22.4%. This is because: the twisting-untwisting process can increase the covering effect of the outer yarn on the core yarn while retaining the micro-gaps between the core yarn fibers. During stretching, the outer yarn and the core yarn are stressed synchronously. However, the impregnation method restricts the elastic deformation of the fibers, and the fibers cannot buffer the stress through appropriate slippage, causing the yarn to break suddenly during stretching. This reduces the breaking strength and breaking elongation of Comparative Example 2. The hot melt adhesive of the impregnation will fill the gap between the outer yarn and the core yarn. After curing, the two are tightly bonded, and the capillary channels at the interface between the outer yarn and the core yarn will be blocked. Moisture is difficult to diffuse between the core yarn and the outer yarn, which inhibits the wicking effect and reduces the wicking height. The rigidity of the impregnated yarn increases due to the curing of the adhesive layer. The yarn structure is dense and the loft is low. During the fabric weaving process, the gaps between the warp and weft yarns are compressed, and gas is difficult to circulate through the gaps inside or between the yarns, reducing the air permeability of the fabric.

[0075] Example 2

[0076] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn differs from Example 1 only in that the ratio of the fineness of the core yarn before passing through the twister to the twist of the core yarn after passing through the twister is 1D:11 twists / m.

[0077] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 193.4 dtex, a breaking strength of 3.0 cN / dtex, a breaking elongation of 31.4%, and a wicking height of 9.0 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 159 mm / s.

[0078] Compared with Example 1, the linear density of the mechanically covered yarn obtained in Example 2 did not change significantly, but the breaking strength decreased by 14.3%, the breaking elongation decreased by 6.8%, the wicking height decreased by 11.8%, and the air permeability of the fabric decreased by 8.6%. This is because: when the twist is lower, the fiber cohesion is relatively loose, the number of glue points after untwisting is less and the distance between them is larger, and the fibers slip or break to some extent during stretching, resulting in a decrease in breaking strength and breaking elongation; fewer glue points weaken the adhesion of water between fibers, slow down the climbing speed, and reduce the wicking height; the yarn bonding is loose, and the yarns are squeezed against each other during weaving, and the loose yarns are stretched and deformed to some extent, resulting in a decrease in the orderliness of the internal pore distribution of the fabric, an increase in gas flow resistance, and a decrease in air permeability.

[0079] Example 3

[0080] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn differs from Example 1 only in that the ratio of the fineness of the core yarn before passing through the twister to the twist of the core yarn after passing through the twister is 1D:18 twists / m.

[0081] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 194.5 dtex, a breaking strength of 3.2 cN / dtex, a breaking elongation of 30.7%, and a wicking height of 8.8 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 153 mm / s.

[0082] Compared with Example 1, the linear density of the mechanically covered yarn obtained in Example 3 did not change significantly, but the breaking strength decreased by 8.6%, the breaking elongation decreased by 8.9%, the wicking height decreased by 13.7%, and the fabric's air permeability decreased by 12.1%. This is because: when the twist is high, the fibers are excessively spirally wound, and the adhesive dots are forcibly squeezed into the narrow spiral gaps, forming local adhesive dot accumulation. After untwisting, the accumulated adhesive dots may form hard knots. When the covered yarn is stretched, the force cannot be transmitted smoothly and evenly, but can only be concentrated in the hard knots and surrounding areas. This causes the material at the hard knots to reach its bearing limit prematurely. During stretching, the yarn cannot deform flexibly enough, resulting in a decrease in breaking strength and breaking elongation. Local adhesive dot accumulation may block some capillary channels, making it difficult for moisture to fully penetrate and diffuse, resulting in a decrease in wicking height. The fiber spiral is tighter, the gaps between the yarns after weaving are reduced, the air circulation is worse, and the fabric's air permeability is reduced.

[0083] Example 4

[0084] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn, employing methods such as... Figure 1 and Figure 2 The specific steps for the device shown are as follows:

[0085] (1) Prepare raw materials;

[0086] Hot melt adhesive: PES hot melt adhesive masterbatch, manufactured by Suzhou Huiyang Adhesive Products Co., Ltd.

[0087] Core yarn: Spandex yarn, specification 20D / 3F;

[0088] Leather yarn: Polyester DTY yarn, specification 75D / 72F, the cross-section of the monofilament is trilobal;

[0089] (2) A hot melt adhesive layer is formed on the surface of the core yarn;

[0090] Adopting such Figure 1 The device shown places hot melt adhesive 102 in a heating tank and heats it to 140°C to melt the hot melt adhesive 102. First, the core yarn 101 passes sequentially through the upper edge of the guide roller 301, the lower edge of the first pressure roller 302, the lower edge of the second pressure roller 303, and then through the upper edge of the glue-feeding roller 304. The molten hot melt adhesive 102 is transferred to the core yarn 101 through the glue-feeding roller 304. Then, the core yarn 101 passes through the lower edge of the third pressure roller 305, and then sequentially through the twister 306, the untwisting device 307, and the scraper 103. Finally, the hot melt adhesive 102 placed on the core yarn 101 at room temperature (20-25°C) solidifies. The thickness of the hot melt adhesive layer on the surface of the core yarn 101 is 7μm.

[0091] The peripheral surface of the glue-feeding roller 304 is uneven, with a roughness of 1.5 μm. The diameter of the glue-feeding roller 304 is 300 mm. The glue-feeding roller 304 is half-immersed in the molten hot melt adhesive 102 and rotates uniformly around its own central axis at a speed of 100 r / min. The wrapping angle of the core yarn 101 on the glue-feeding roller 304 is 70°.

[0092] The core yarn 101 has a twist of 0 before passing through the twister 306, and the core yarn 101 has a twist of 0 after passing through the untwisting device 307;

[0093] The ratio of the fineness of the core yarn 101 before passing through the twister 306 to the twist of the core yarn 101 after passing through the twister 306 is 1D:14 twists / m;

[0094] The core yarn 101 travels for 1 second between the feeding roller 304 and the twister 306, 2.5 seconds between the twister 306 and the untwisting device 307, and 1.5 seconds between the untwisting device 307 and the scraper 103. The core yarn travels at a constant speed of 95 m / min.

[0095] (3) Wrap the outer yarn over the core yarn;

[0096] Adopting such Figure 2The device shown in the figure guides the core yarn 101 obtained in step (2) into the center tube of the hollow spindle 203 from the bottom and out from the top under the guidance of the first yarn guide roller 201 and the yarn guide 202 of the covering machine. During this process, the leather yarn 204 is unwound as the hollow spindle 203 rotates. When the leather yarn 204 and the core yarn 101 reach the confluence guide hook 205, the leather yarn 204 is wrapped around the core yarn 101 in a spiral manner to obtain the core yarn 101 with the surface covered by the leather yarn 204.

[0097] The wrapping twist is 300 twists / m, the rotation speed of the hollow spindle 203 is 15000 r / min, and the draft ratio of the core yarn 101 is 3.2.

[0098] (4) Heat the hot melt adhesive to soften it, then cool it down to solidify it;

[0099] Adopting such Figure 2 The device shown in step (3) has a core yarn 101 of surface-coated yarn 204. After passing through the second yarn guide roller 210 and the yarn guide rod 211, the core yarn 101 of surface-coated yarn 204 is controlled to pass through the hot air area 206 and the cold air area 207 in sequence, thus obtaining a low-twist, high-strength, and highly breathable mechanically coated yarn.

[0100] The temperature of hot air zone 206 is 115℃, the length of hot air zone 206 is 10cm, and the wind speed of hot air zone 206 is 1m / s.

[0101] The temperature of cold air zone 207 is 20℃, the length of cold air zone 207 is 20cm, and the wind speed of cold air zone 207 is 0.5m / s;

[0102] (5) Winding;

[0103] Adopting such Figure 2 The device shown has a low-twist, high-strength, and highly breathable mechanically covered yarn wound onto the bobbin driven by the friction drive of the winding roller 209 as the traverse yarn guide 208 swings back and forth, ready for use.

[0104] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 96.2 dtex, a breaking strength of 3.9 cN / dtex, a breaking elongation of 25.3%, and a wicking height of 14.1 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 387 mm / s.

[0105] Example 5

[0106] The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn differs from Example 4 only in that the ratio of the fineness of the core yarn before passing through the twister to the twist of the core yarn after passing through the twister is 1D:11 twists / m.

[0107] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 95.8 dtex, a breaking strength of 3.4 cN / dtex, a breaking elongation of 23.8%, and a wicking height of 13.2 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 362 mm / s.

[0108] Compared with Example 4, the linear density of the mechanically coated yarn obtained in Example 5 did not change significantly, but the breaking strength decreased by 12.8%, the breaking elongation decreased by 5.9%, the wicking height decreased by 6.4%, and the air permeability of the fabric decreased by 6.5%. The reasons are the same as in Example 2.

[0109] Example 6

[0110] The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn differs from Example 4 only in that the ratio of the fineness of the core yarn before passing through the twister to the twist of the core yarn after passing through the twister is 1D:18 twists / m.

[0111] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 96.7 dtex, a breaking strength of 3.5 cN / dtex, a breaking elongation of 22.7%, and a core suction height of 12.6 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 355 mm / s.

[0112] Compared with Example 4, the linear density of the mechanically covered yarn obtained in Example 6 did not change significantly, but the breaking strength decreased by 10.2%, the breaking elongation decreased by 10.3%, the wicking height decreased by 10.6%, and the air permeability of the fabric decreased by 8.3%. The reasons are the same as in Example 3.

[0113] Example 7

[0114] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn, employing methods such as... Figure 1 and Figure 2 The specific steps for the device shown are as follows:

[0115] (1) Prepare raw materials;

[0116] Hot melt adhesive: PA hot melt adhesive masterbatch, manufactured by Suzhou Huiyang Adhesive Products Co., Ltd.;

[0117] Core yarn: Spandex yarn, specification 40D / 3F;

[0118] Leather yarn: Nylon DTY yarn, specification 70D / 24F, the cross-section of the single filament is triangular;

[0119] (2) A hot melt adhesive layer is formed on the surface of the core yarn;

[0120] Adopting such Figure 1The device shown places hot melt adhesive 102 in a heating tank and heats it to 130°C to melt the hot melt adhesive 102. First, the core yarn 101 passes sequentially through the upper edge of the guide roller 301, the lower edge of the first pressure roller 302, the lower edge of the second pressure roller 303, and then through the upper edge of the glue-feeding roller 304. The molten hot melt adhesive 102 is transferred to the core yarn 101 through the glue-feeding roller 304. Then, the core yarn 101 passes through the lower edge of the third pressure roller 305, and then sequentially through the twister 306, the untwisting device 307, and the scraper 103. Finally, the hot melt adhesive 102 placed on the core yarn 101 at room temperature (20-25°C) solidifies. The thickness of the hot melt adhesive layer on the surface of the core yarn 101 is 7μm.

[0121] The peripheral surface of the glue-feeding roller 304 is uneven, with a roughness of 1.5 μm. The diameter of the glue-feeding roller 304 is 300 mm. The glue-feeding roller 304 is half-immersed in the molten hot melt adhesive 102 and rotates uniformly around its own central axis at a speed of 100 r / min. The wrapping angle of the core yarn 101 on the glue-feeding roller 304 is 70°.

[0122] The core yarn 101 has a twist of 0 before passing through the twister 306, and the core yarn 101 has a twist of 0 after passing through the untwisting device 307;

[0123] The ratio of the fineness of the core yarn 101 before passing through the twister 306 to the twist of the core yarn 101 after passing through the twister 306 is 1D:14 twists / m;

[0124] The core yarn 101 travels for 1 second between the feeding roller 304 and the twister 306, 2.5 seconds between the twister 306 and the untwisting device 307, and 1.5 seconds between the untwisting device 307 and the scraper 103. The core yarn travels at a constant speed of 95 m / min.

[0125] (3) Wrap the outer yarn over the core yarn;

[0126] Adopting such Figure 2 The device shown in the figure guides the core yarn 101 obtained in step (2) into the center tube of the hollow spindle 203 from the bottom and out from the top under the guidance of the first yarn guide roller 201 and the yarn guide 202 of the covering machine. During this process, the leather yarn 204 is unwound as the hollow spindle 203 rotates. When the leather yarn 204 and the core yarn 101 reach the confluence guide hook 205, the leather yarn 204 is wrapped around the core yarn 101 in a spiral manner to obtain the core yarn 101 with the surface covered by the leather yarn 204.

[0127] The wrapping twist is 300 twists / m, the rotation speed of the hollow spindle 203 is 15000 r / min, and the draft ratio of the core yarn 101 is 3.2.

[0128] (4) Heat the hot melt adhesive to soften it, then cool it down to solidify it;

[0129] Adopting such Figure 2 The device shown in step (3) has a core yarn 101 of surface-coated yarn 204. After passing through the second yarn guide roller 210 and the yarn guide rod 211, the core yarn 101 of surface-coated yarn 204 is controlled to pass through the hot air area 206 and the cold air area 207 in sequence, thus obtaining a low-twist, high-strength, and highly breathable mechanically coated yarn.

[0130] The temperature of hot air zone 206 is 105℃, the length of hot air zone 206 is 10cm, and the wind speed of hot air zone 206 is 1m / s.

[0131] The temperature of cold air zone 207 is 20℃, the length of cold air zone 207 is 20cm, and the wind speed of cold air zone 207 is 0.5m / s;

[0132] (5) Winding;

[0133] Adopting such Figure 2 The device shown has a low-twist, high-strength, and highly breathable mechanically covered yarn wound onto the bobbin driven by the friction drive of the winding roller 209 as the traverse yarn guide 208 swings back and forth, ready for use.

[0134] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 112.7 dtex, a breaking strength of 4.4 cN / dtex, a breaking elongation of 41.2%, and a wicking height of 52.3 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 343 mm / s.

[0135] Example 8

[0136] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn differs from Example 7 only in that the ratio of the fineness of the core yarn before passing through the twister to the twist of the core yarn after passing through the twister is 1D:11 twists / m.

[0137] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 112.3 dtex, a breaking strength of 3.9 cN / dtex, a breaking elongation of 38.7%, and a wicking height of 48.3 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 321 mm / s.

[0138] Compared with Example 7, the linear density of the mechanically covered yarn obtained in Example 8 did not change significantly, but the breaking strength decreased by 11.4%, the breaking elongation decreased by 6.1%, the wicking height decreased by 7.6%, and the air permeability of the fabric decreased by 6.4%. The reasons are the same as in Example 2.

[0139] Example 9

[0140] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn differs from Example 7 only in that the ratio of the fineness of the core yarn before passing through the twister to the twist of the core yarn after passing through the twister is 1D:18 twists / m.

[0141] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 113.1 dtex, a breaking strength of 4.0 cN / dtex, a breaking elongation of 37.2%, and a wicking height of 46.1 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 310 mm / s.

[0142] Compared with Example 7, the linear density of the mechanically covered yarn obtained in Example 9 did not change significantly, but the breaking strength decreased by 9.1%, the breaking elongation decreased by 9.7%, the wicking height decreased by 11.9%, and the air permeability of the fabric decreased by 9.6%. The reasons are the same as in Example 3.

[0143] Example 10

[0144] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn, employing methods such as... Figure 1 and Figure 2 The specific steps for the device shown are as follows:

[0145] (1) Prepare raw materials;

[0146] Hot melt adhesive: PA hot melt adhesive masterbatch, manufactured by Suzhou Huiyang Adhesive Products Co., Ltd.;

[0147] Core yarn: Spandex yarn, specification 20D / 3F;

[0148] Leather yarn: Nylon DTY yarn, specification 30D / 24F, the cross-section of the monofilament is trilobal;

[0149] (2) A hot melt adhesive layer is formed on the surface of the core yarn;

[0150] Adopting such Figure 1 The device shown places hot melt adhesive 102 in a heating tank and heats it to 130°C to melt the hot melt adhesive 102. First, the core yarn 101 passes sequentially through the upper edge of the guide roller 301, the lower edge of the first pressure roller 302, the lower edge of the second pressure roller 303, and then through the upper edge of the glue-feeding roller 304. The molten hot melt adhesive 102 is transferred to the core yarn 101 through the glue-feeding roller 304. Then, the core yarn 101 passes through the lower edge of the third pressure roller 305, and then sequentially through the twister 306, the untwisting device 307, and the scraper 103. Finally, the hot melt adhesive 102 placed on the core yarn 101 at room temperature (20-25°C) solidifies. The thickness of the hot melt adhesive layer on the surface of the core yarn 101 is 7μm.

[0151] The peripheral surface of the glue-feeding roller 304 is uneven, with a roughness of 1.5 μm. The diameter of the glue-feeding roller 304 is 300 mm. The glue-feeding roller 304 is half-immersed in the molten hot melt adhesive 102 and rotates uniformly around its own central axis at a speed of 100 r / min. The wrapping angle of the core yarn 101 on the glue-feeding roller 304 is 70°.

[0152] The core yarn 101 has a twist of 0 before passing through the twister 306, and the core yarn 101 has a twist of 0 after passing through the untwisting device 307;

[0153] The ratio of the fineness of the core yarn 101 before passing through the twister 306 to the twist of the core yarn 101 after passing through the twister 306 is 1D:15 twists / m;

[0154] The core yarn 101 travels for 1 second between the feeding roller 304 and the twister 306, 2.5 seconds between the twister 306 and the untwisting device 307, and 1.5 seconds between the untwisting device 307 and the scraper 103. The core yarn travels at a constant speed of 95 m / min.

[0155] (3) Wrap the outer yarn over the core yarn;

[0156] Adopting such Figure 2 The device shown in the figure guides the core yarn 101 obtained in step (2) into the center tube of the hollow spindle 203 from the bottom and out from the top under the guidance of the first yarn guide roller 201 and the yarn guide 202 of the covering machine. During this process, the leather yarn 204 is unwound as the hollow spindle 203 rotates. When the leather yarn 204 and the core yarn 101 reach the confluence guide hook 205, the leather yarn 204 is wrapped around the core yarn 101 in a spiral manner to obtain the core yarn 101 with the surface covered by the leather yarn 204.

[0157] The wrapping twist is 300 twists / m, the rotation speed of the hollow spindle 203 is 15000 r / min, and the draft ratio of the core yarn 101 is 3.2.

[0158] (4) Heat the hot melt adhesive to soften it, then cool it down to solidify it;

[0159] Adopting such Figure 2 The device shown in step (3) has a core yarn 101 of surface-coated yarn 204. After passing through the second yarn guide roller 210 and the yarn guide rod 211, the core yarn 101 of surface-coated yarn 204 is controlled to pass through the hot air area 206 and the cold air area 207 in sequence, thus obtaining a low-twist, high-strength, and highly breathable mechanically coated yarn.

[0160] The temperature of hot air zone 206 is 105℃, the length of hot air zone 206 is 10cm, and the wind speed of hot air zone 206 is 1m / s.

[0161] The temperature of cold air zone 207 is 20℃, the length of cold air zone 207 is 20cm, and the wind speed of cold air zone 207 is 0.5m / s;

[0162] (5) Winding;

[0163] Adopting such Figure 2 The device shown has a low-twist, high-strength, and highly breathable mechanically covered yarn wound onto the bobbin driven by the friction drive of the winding roller 209 as the traverse yarn guide 208 swings back and forth, ready for use.

[0164] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 50.6 dtex, a breaking strength of 4.6 cN / dtex, a breaking elongation of 32.5%, and a core suction height of 65.8 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 515 mm / s.

[0165] Example 11

[0166] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn differs from Example 10 only in that the ratio of the fineness of the core yarn before passing through the twister to the twist of the core yarn after passing through the twister is 1D:11 twists / m.

[0167] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 50.3 dtex, a breaking strength of 4.1 cN / dtex, a breaking elongation of 30.4%, and a wicking height of 61.0 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 483 mm / s.

[0168] Compared with Example 10, the linear density of the mechanically covered yarn obtained in Example 11 did not change significantly, but the breaking strength decreased by 10.9%, the breaking elongation decreased by 6.5%, the wicking height decreased by 7.3%, and the air permeability of the fabric decreased by 6.2%. The reasons are the same as in Example 2.

[0169] Example 12

[0170] A method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn differs from Example 10 only in that the ratio of the fineness of the core yarn before passing through the twister to the twist of the core yarn after passing through the twister is 1D:18 twists / m.

[0171] The final low-twist, high-strength, and high-breathability mechanically covered yarn has a linear density of 51.0 dtex, a breaking strength of 4.3 cN / dtex, a breaking elongation of 29.2%, and a wicking height of 59.4 mm. The fabric made from the low-twist, high-strength, and high-breathability mechanically covered yarn has an air permeability of 472 mm / s.

[0172] Compared with Example 10, the linear density of the mechanically covered yarn obtained in Example 12 did not change significantly, but the breaking strength decreased by 6.5%, the breaking elongation decreased by 10.2%, the wicking height decreased by 9.7%, and the air permeability of the fabric decreased by 8.3%. The reasons are the same as in Example 3.

Claims

1. A method for preparing a low twist high strength high air permeability mechanical wrap yarn, characterized in that, After the hot melt adhesive layer is formed on the surface of the core yarn, the sheath yarn is wrapped on the core yarn, the hot melt adhesive is softened by heating, and then the hot melt adhesive is solidified by cooling, so that the low-twist high-strength high-breathability mechanical wrapped yarn is obtained. The process of forming the hot melt adhesive layer on the surface of the core yarn is: after the molten hot melt adhesive is transferred to the core yarn through the glue roller, the core yarn passes through the twisting device, the untwisting device and the scraper in sequence, and then is naturally cooled to solidify the hot melt adhesive on the core yarn, wherein the surface of the glue roller is uneven, the glue roller is half immersed in the molten hot melt adhesive and rotates at a uniform speed around its central axis, the molten hot melt adhesive is located in the heating tank, the twist of the core yarn before passing through the twisting device is 0, and the twist of the core yarn after passing through the untwisting device is 0. The ratio of the fineness of the core yarn to the twist of the core yarn after passing through the twisting device is 1D:14-15 twists / m.

2. The method for preparing a low twist high strength high air permeability mechanical wrap yarn according to claim 1, characterized in that, The roughness of the surface of the glue roller is 1.5 μm, the diameter of the glue roller is 300 mm, the wrapping angle of the core yarn on the glue roller is 70°, the running time of the core yarn between the glue roller and the twisting device is 1 s, the running time of the core yarn between the twisting device and the untwisting device is 2.5 s, the running time of the core yarn between the untwisting device and the scraper is 1.5 s, and the rotation speed of the glue roller is 100 r / min. The core yarn runs at a uniform speed of 95 m / min during the process of forming the hot melt adhesive layer on the surface of the core yarn.

3. The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn according to claim 1, characterized in that, The thickness of the hot melt adhesive layer is 7 μm.

4. The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn according to claim 1, characterized in that, The process of wrapping the sheath yarn on the core yarn is: the core yarn is guided by the first yarn guide of the wrapping machine, enters the central tube of the hollow spindle from the lower end and is drawn out from the upper end, in this process, the sheath yarn is unwound with the rotation of the hollow spindle, when the sheath yarn and the core yarn reach the convergence guide hook, the sheath yarn is wrapped on the core yarn in a spiral manner.

5. The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn according to claim 4, characterized in that, The wrapping twist is 300 twists / m, the rotation speed of the hollow spindle is 15000 r / min, and the draft ratio of the core yarn is 3.

2.

6. The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn according to claim 1, characterized in that, After the hot melt adhesive is softened by heating, the hot melt adhesive is solidified by cooling, which means: the core yarn wrapped with the sheath yarn passes through the hot air area and the cold air area in sequence.

7. The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn according to claim 6, characterized in that, The temperature of the hot air area is 5-10 ℃ higher than the softening temperature of the hot melt adhesive, the length of the hot air area is 10 cm, and the wind speed of the hot air area is 1 m / s; the temperature of the cold air area is 20 ℃, the length of the cold air area is 20 cm, and the wind speed of the cold air area is 0.5 m / s.

8. The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn according to claim 1, characterized in that, The core yarn is spandex filament with a specification of 20-40 D / 3F; the sheath yarn is polyester DTY filament with a specification of 75-150 D / 72-144 F, or the sheath yarn is nylon DTY filament with a specification of 30-70 D / 24 F.

9. The method for preparing a low-twist, high-strength, and highly breathable mechanically covered yarn according to claim 1, characterized in that, The linear density of the low-twist high-strength high-breathability mechanical wrapped yarn is 50.3-194.5 dtex, the breaking strength is 3.0-4.6 cN / dtex, the breaking elongation is 22.7-41.2%, the wicking height is 8.8-65.8 mm, and the air permeability of the fabric made of the low-twist high-strength high-breathability mechanical wrapped yarn is 153-515 mm / s.

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