Elastic covering yarn and preparation method thereof

Abstract

The invention discloses an elastic core-spun yarn and a preparation method thereof, and relates to the technical field of textile materials, the elastic core-spun yarn is composed of a core yarn layer and a plurality of wrapping layers, and specifically, the core yarn layer is made of polyurethane elastic fibers and provides inner core support for the core-spun yarn. The densities and the arrangement directions of the fibers of each layer are different, graded protection and progressive stress buffering of the core yarn are achieved, the core yarn is effectively protected through high density and radial arrangement of the fibers of the inner layer, external mechanical damage is prevented, a good stress dispersion effect is provided through oblique arrangement of the middle layer, the overall elastic recovery performance is enhanced, and the service life of the core yarn is prolonged. Due to the low density and longitudinal arrangement of the outer layer, the softness and comfort of the yarn are improved, meanwhile, additional wear resistance is provided, and due to the multi-layer structural design, the core-spun yarn can still keep the excellent elastic recovery rate and durability in the multiple stretching and using processes.

Description

Technical Field

[0001] The invention relates to the technical field of textile materials, in particular to an elastic core-spun yarn and a preparation method thereof. Background Art

[0002] As a high-performance textile material, elastic core-spun yarn has been widely used in many fields such as clothing, home textiles, sports equipment, etc. due to its unique structure and excellent physical properties. Traditional core-spun yarn is usually made of one or more fiber materials wrapped and twisted around a core yarn to improve the elasticity, wear resistance and comfort of the yarn. With the continuous advancement of textile technology and the increasing requirements of consumers for product quality, the performance requirements for elastic core-spun yarn are also getting higher and higher, especially for those application scenarios that need to withstand large stretching and recovery of deformation, such as tights, sports pants, etc., which put higher requirements on the elastic recovery rate, wear resistance and comfort of the elastic core-spun yarn.

[0003] At present, the existing elastic core-spun yarn is relatively single in the selection of core yarn materials, and only one elastic fiber is used as the core yarn, which limits the improvement of the comprehensive performance of the yarn. In addition, the fiber composition and arrangement of the coating layer often lack reasonable design, resulting in deficiencies in the elastic recovery rate, wear resistance and comfort of the yarn. Especially in the preparation of multi-layer coating structures, how to ensure the uniform distribution and close bonding of each layer of fibers, and how to optimize the performance of the yarn through reasonable twisting adjustment are problems that need to be urgently solved in the current elastic core-spun yarn preparation technology. Summary of the invention

[0004] The purpose of the present invention is to make up for the shortcomings of the prior art and to provide an elastic core-spun yarn and a preparation method thereof. It can significantly improve the elastic recovery rate and wear resistance of the yarn by adopting polyurethane elastic fiber as the core yarn material and combining the design of a multi-layer covering layer. By optimizing the composition and arrangement of each layer of fibers, the softness and comfort of the yarn are further improved.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: On the one hand, an elastic core-spun yarn is composed of a core yarn layer and multiple covering layers, specifically:

[0006] The core yarn layer is composed of polyurethane elastic fiber, which provides inner core support for the core-spun yarn;

[0007] The multi-layer covering layer is composed of an inner layer, a middle layer and an outer layer, each layer having a different fiber ratio and arrangement direction, and providing graded protection and progressive stress buffering for the core yarn, specifically including:

[0008] Inner layer: 70% polyester fiber and 30% nylon fiber blended, arranged in radial direction, used to directly protect the core yarn;

[0009] Middle layer: Blended with 50% cotton fiber and 50% modal fiber, arranged in an oblique direction, providing stress buffering and transition, and restoring the overall elastic properties;

[0010] Outer layer: 60% cotton and 40% polyester blend, arranged in the machine direction, providing the softness and comfort of the yarn while providing additional abrasion resistance.

[0011] Furthermore, the linear density of the inner polyester fiber of the coating layer is 20-30dtex, the length is 20-30mm, the twist is 600-800 twists / m, and the linear density of the nylon fiber is 15-25dtex, the length is 18-28mm, and the twist is 500-700 twists / m, so that the inner layer can fit closely to the core yarn.

[0012] Furthermore, the length of the middle layer cotton fiber of the coating layer is 25-35mm, the linear density is 12-20dtex, and the twist is 700-900 twists / m, and the length of the modal fiber is 30-40mm, the linear density is 10-18dtex, and the twist is 600-800 twists / m to ensure stress buffering and transition effects.

[0013] Furthermore, the outer cotton fiber of the coating layer has a twist of 800-1000 twists / m, a linear density of 10-15 dtex, and a length of 30-40 mm, and the polyester fiber has a twist of 700-900 twists / m, a linear density of 12-18 dtex, and a length of 25-35 mm.

[0014] Furthermore, the thickness of the inner layer of the coating accounts for 30%-40% of the total thickness of the multi-layer coating, the thickness of the middle layer accounts for 30%-40%, and the thickness of the outer layer accounts for 20%-40%.

[0015] On the other hand, a method for preparing an elastic core-spun yarn is provided, wherein the specific steps of the method are:

[0016] Pre-twisting of the core yarn layer: Select polyurethane elastic fiber as the core yarn material, pre-twist and preheat the core yarn, the twist degree is 200-400T / m, the preheating temperature is 40-60℃, and the preheating time is 5-10 minutes, so that the core yarn has a preliminary structural stability;

[0017] Adding covering fiber: prepare covering fibers of different layers, and evenly cover the inner covering fiber on the pre-twisted core yarn. The covering method adopts air jet to evenly spray.

[0018] First twisting: The core yarn covered with the inner layer fiber is twisted for the first time, with a twist degree of 300-500T / m, so that the inner layer fiber and the core yarn are closely combined to form a stable inner layer structure;

[0019] Middle layer coating: The middle layer coating fiber is evenly coated on the yarn after the first twisting, and the coating method is the same as the inner layer;

[0020] Secondary twisting: The yarn covered with the middle layer fiber is twisted twice, with a twist degree of 400-600T / m, so that the middle layer fiber is closely combined with the inner layer fiber and the core yarn to form a stable middle layer structure;

[0021] Outer layer coating: The outer layer coating fiber is evenly coated on the yarn after secondary twisting, and the coating method is the same as the inner layer and the middle layer;

[0022] Final twisting: The yarn covered with the outer layer fiber is finally twisted with a twist degree of 500-700T / m, so that the outer layer fiber is closely combined with the middle layer fiber and the core yarn to form a stable outer layer structure;

[0023] Post-treatment: The yarn is post-treated after final twisting, including heat setting, oiling and cooling.

[0024] Furthermore, the twisting direction of the pre-twisting of the core yarn layer is in the Z direction, and the twisting directions of the first twisting, the second twisting and the final twisting of the covering layer are all in the S direction.

[0025] Furthermore, in the post-treatment process, the temperature and time of heat setting are 100-150° C., the time is 1-3 minutes, the oil agent used in the oiling treatment is silicone oil, and the amount of the oil agent added is 0.5%-2.0% of the weight of the yarn.

[0026] Furthermore, in the post-treatment process, the yarn is cooled after heat setting, the cooling temperature is from room temperature to 40° C., and the cooling time is 5-15 minutes to stabilize the structure and performance of the yarn.

[0027] Compared with the prior art, the elastic core-spun yarn and the preparation method thereof have the following beneficial effects:

[0028] 1. The elastic core-spun yarn of the present invention adopts a multi-layer structure design, and each layer has different fiber density and arrangement direction, thereby realizing graded protection and progressive stress buffering of the core yarn. The high density and radial arrangement of the inner layer fibers effectively protect the core yarn and prevent external mechanical damage; the oblique arrangement of the middle layer provides a good stress dispersion effect and enhances the overall elastic recovery performance; the low density and longitudinal arrangement of the outer layer increase the softness and comfort of the yarn, and provide additional wear resistance. This multi-layer structure design enables the core-spun yarn to maintain excellent elastic recovery rate and durability during multiple stretching and use, significantly extending the service life of the yarn.

[0029] 2. The method for preparing the elastic core-spun yarn of the present invention realizes the precise preparation of the multi-layer coating structure and the close combination of the fibers by adopting the process steps of air jet coating and multiple twisting. This method not only improves the production efficiency and quality stability of the product, but also reduces the production cost and energy consumption. Especially in the preparation of the multi-layer coating structure, the twisting parameters of each layer of fibers are precisely controlled to ensure the uniform distribution and close combination of each layer of fibers, thereby improving the overall performance and durability of the yarn.

[0030] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 The present invention is a flow chart of a method for preparing an elastic core-spun yarn. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Embodiment 1

[0035] This embodiment describes in detail a specific process of a method for preparing an elastic core-spun yarn, and shows in detail specific preparation parameters and performance test data to verify the effectiveness and superiority of the invention.

[0036] Pre-twisting of the core yarn layer: Polyurethane elastic fiber is used as the core yarn material. In the pre-twisting stage, the twist degree is set to 300T / m. Under this twist degree, the core yarn begins to initially form a stable structure, and the cohesion between the fibers is enhanced. Then, preheating treatment is carried out, and the temperature is controlled at 50°C for 8 minutes, which further improves the stability and elastic uniformity of the core yarn. During the preheating process, the fibers are heated evenly, and the thermal motion of the molecules gradually tends to be stable, thereby avoiding local performance differences caused by uneven temperature.

[0037] Addition of covering fiber: The inner covering fiber is blended by 70% polyester fiber and 30% nylon fiber. Among them, polyester fiber has high strength and good heat resistance, linear density of 25dtex, length of 25mm, twist of 700 twists / m, so that polyester fiber plays an important role in providing support and protection of core yarn. The linear density of nylon fiber is 20dtex, length of 20mm, twist of 600 twists / m. After the two fibers are mixed in a specific proportion, they are evenly sprayed and coated on the pre-twisted core yarn by air jet, ensuring that the fibers can be evenly dispersed and closely fit the surface of the core yarn to form a uniform and tight inner covering structure; the middle layer is blended by 50% cotton fiber and 50% modal fiber. Cotton fiber has good hygroscopicity and softness, linear density of 15dtex, length of 30mm, twist of 800 twists / m, which can effectively absorb moisture and improve the comfort of yarn. The linear density of modal fiber is 12dtex, length of 35mm, twist of 700 twists / m. The synergistic effect of these two fibers makes the middle layer perform excellently in stress buffering and transition. It is also evenly coated on the yarn after the first twist by air jet, ensuring the uniformity and stability of the middle layer coating. The outer layer is blended with 60% cotton fiber and 40% polyester fiber. The outer cotton fiber has a linear density of 12dtex, a length of 35mm, and a twist of 900 twists / m, which mainly provides the softness and appearance texture of the yarn. The polyester fiber has a linear density of 15dtex, a length of 30mm, and a twist of 800 twists / m, which enhances the wear resistance and overall structural strength of the yarn. Through the air jet process, the outer layer coating fiber is evenly coated on the yarn after the second twist, so that the yarn has good external protection and performance.

[0038] Twisting steps for each layer: The core yarn coated with the inner layer fiber is twisted for the first time, with a twist degree of 400T / m. The inner layer fiber is tightly combined with the core yarn to form a stable inner layer structure; after the middle layer coating fiber is evenly coated on the yarn after the first twist, a second twist is performed with a twist degree of 500T / m. This twisting makes the middle layer fiber further tightly combined with the inner layer fiber and the core yarn to form a stable middle layer structure. The twisting direction cooperates with the first twisting to form a specific spiral structure, which is conducive to the transmission and dispersion of stress between the layers; the outer layer coating fiber is coated on the yarn after the second twist, and then the final twist is performed with a twist degree of 600T / m, which makes the outer layer fiber tightly combined with the middle layer fiber and the core yarn to form a complete and stable outer layer structure. After the final twisting is completed, the overall structure of the yarn is tight, and each layer of fiber works together to give full play to their respective performance advantages.

[0039] Post-treatment: The yarn after final twisting is heat-set at 120℃ for 2 minutes. During the heat-setting process, the fiber structure inside the yarn is further adjusted and stabilized. High temperature rearranges the fiber molecular chain, eliminates the internal stress caused by twisting and coating, and fixes the relative position between each layer of fiber, improving the dimensional stability and shape retention of the yarn. After heat setting, oiling is performed. The oil used is silicone oil, and the addition amount is 1.0% of the weight of the yarn. Silicone oil has good lubricity and antistatic properties, and can form a uniform protective film on the surface of the yarn. This protective film reduces the friction coefficient of the yarn during subsequent processing and use, reduces the electrostatic adsorption between fibers, and improves the spinnability and performance of the yarn. After oiling, cooling is performed. The cooling temperature is controlled from room temperature to 30℃, and the cooling time is 10 minutes. During the cooling process, the fibers inside the yarn gradually stabilize to form the final high-performance elastic core-spun yarn structure.

[0040] Performance test data: The elastic core-spun yarn prepared in this embodiment has a breaking strength of 22.0 cN / Tex, and can maintain structural integrity under complex stress; the elongation at break is 18.5%, indicating that it has good elastic deformation performance. When stretched, the internal fibers work together to effectively disperse the stress and can recover quickly; the elastic recovery rate is 96%, that is, after multiple stretching cycles, it can still maintain excellent elastic recovery ability; the wear resistance is 12,000 times, and the wear-resistant protection system jointly constructed by the outer and inner fibers enables it to withstand long-term friction and wear, greatly extending the service life of the product and reducing maintenance costs.

[0041] In summary, the elastic core-spun yarn prepared in this embodiment performs well in key performance indicators such as breaking strength, elongation at break, elastic recovery rate and abrasion resistance times, which fully verifies the effectiveness and superiority of the present invention and has broad application prospects and market potential.

[0042] Embodiment 2

[0043] Pre-twisting of the core yarn layer: polyurethane elastic fiber is selected as the core yarn material, and the pre-twisting degree is set to 350T / m. This twisting degree enables the core yarn to quickly obtain strong structural stability, and the fibers are tightly bonded. During the preheating treatment, the temperature is maintained at 55°C for 6 minutes, which can effectively improve the elastic uniformity of the core yarn, the fiber molecules are heated evenly, the thermal movement is stable, and local performance fluctuations are avoided.

[0044] Covering fiber addition: Inner layer: It is blended with 70% polyester fiber (linear density 22dtex, length 22mm, twist 750 twist / m) and 30% nylon fiber (linear density 18dtex, length 18mm, twist 650 twist / m). When the air flow is jet coated, the air flow speed and the jet angle are strictly controlled to make the fibers fit the core yarn evenly and tightly to form a stable inner layer. The polyester fiber provides strength support, and the nylon fiber enhances wear resistance; Middle layer: It is blended with 50% cotton fiber (linear density 13dtex, length 28mm, twist 850 twist / m) and 50% modal fiber (linear density 10dtex, length 32mm, twist 750 twist / m). The yarn after the first twist is evenly coated by air jet. The cotton fiber is hygroscopic and soft, and the modal fiber has good elasticity. The two work together to achieve good stress buffering and transition, ensuring uniform and stable coating; the outer layer is a blend of 60% cotton fiber (linear density 10dtex, length 32mm, twist 950 twists / m) and 40% polyester fiber (linear density 13dtex, length 25mm, twist 850 twists / m). The yarn after the second twist is coated by the air jet process. The cotton fiber gives a soft texture, and the polyester fiber enhances the wear resistance and structural strength, improving the external protection and performance of the yarn.

[0045] Twisting steps for each layer: First twisting: The core yarn covering the inner layer fiber is twisted for the first time, with a twist degree of 450T / m, so that the inner layer is tightly combined. The equipment speed and tension are precisely controlled to ensure uniform and stable twisting without damaging the fiber and structure; Middle layer covering and secondary twisting: After the middle layer is covered, the secondary twist degree is 550T / m, so that the middle layer is closely connected with the inner layer and the core yarn to form a stable middle layer structure, and the twisting direction is coordinated to form a spiral structure that is beneficial to stress transfer and dispersion; Outer layer covering and final twisting: After the outer layer is covered, the final twist degree is 650T / m, so that the outer layer is closely combined with the middle layer and the core yarn to form a complete and stable outer layer structure, and each layer of fiber synergistically exerts its performance advantages.

[0046] Post-treatment: Heat setting: temperature 130℃, time 1.5 minutes, to optimize and stabilize the yarn fiber structure, rearrange the molecular chain, eliminate internal stress, fix the fiber position, enhance dimensional stability and shape retention; Oiling treatment: Use silicone oil, the addition amount is 1.5% of the yarn weight, silicone oil lubricates and anti-static, forms a film on the yarn surface, reduces the friction coefficient and electrostatic adsorption, and improves spinnability and performance; Cooling treatment: cooling temperature 25-35℃, time 8 minutes, so that the yarn fiber smoothly transitions to room temperature, forming a high-performance elastic core-spun yarn structure.

[0047] Performance test data: Breaking strength 23.5cN / Tex, able to withstand large tensile force; breaking elongation 20.0%, excellent elastic deformation; elastic recovery rate 97%, still maintains high elasticity after multiple stretching; wear resistance 13,000 times, excellent wear resistance, extending product life and reducing costs.

[0048] Embodiment 3

[0049] Pre-twisting of the core yarn layer: polyurethane elastic fiber is used as the core yarn, and the pre-twisting degree is 400T / m, which makes the core yarn structure stable and the fibers tightly bonded. Preheating to 60℃ for 5 minutes effectively improves the elastic stability of the core yarn, and the molecular thermal movement is uniform, avoiding local performance differences.

[0050] Coating fiber addition: Inner layer: 70% polyester fiber (linear density 20dtex, length 20mm, twist 800 twists / m) and 30% nylon fiber (linear density 16dtex, length 16mm, twist 700 twists / m) blended. Air jet coating, precise control of air flow parameters, fiber uniformly and tightly coated core yarn, polyester fiber provides high-strength support, nylon fiber enhances wear resistance; Middle layer: 50% cotton fiber (linear density 12dtex, length 26mm, twist 900 twists / m) and 50% modal fiber (linear density 9dtex, length 30mm, twist 800 twists / m) blended. The air jet is sprayed on the first twisted yarn. The cotton fiber is hygroscopic and soft, and the modal fiber has good elastic recovery. The two work together to optimize stress buffering and transition to ensure uniform coating. The outer layer is blended with 60% cotton fiber (linear density 9dtex, length 30mm, twist 1000 twists / m) and 40% polyester fiber (linear density 12dtex, length 22mm, twist 900 twists / m). The second twisted yarn is coated with air jet, and the cotton fiber gives it a soft appearance, while the polyester fiber improves the overall strength and wear resistance.

[0051] Twisting steps for each layer: First twisting: The core yarn wrapped with the inner layer is twisted for the first time, with a twist degree of 500T / m, which tightly combines the inner layer and the core yarn. The equipment operating parameters are accurately set to ensure the twisting quality; Middle layer covering and secondary twisting: The middle layer is twisted for the second time after covering, with a twist degree of 600T / m, so that the middle layer is firmly combined with the inner layer and the core yarn to form an effective stress buffer structure, and the twisting direction is coordinated to promote the dispersion of stress transfer; Outer layer covering and final twisting: The outer layer is finally twisted after covering, with a twist degree of 700T / m, to build a complete and stable outer layer structure, and each layer works synergistically to optimize the comprehensive performance of the yarn.

[0052] Post-treatment: Heat setting: Heat setting at 140℃ for 1 minute to adjust and stabilize the yarn fiber structure, eliminate twisting and coating stress, and enhance the shape and dimensional stability of the yarn; Oiling treatment: Use silicone oil, the addition amount is 2.0% of the yarn weight, silicone oil forms a protective film, reduces friction and static electricity, and improves spinnability and performance; Cooling treatment: Cooling temperature 30-35℃, time 5 minutes, to stabilize the yarn structure and form high-performance elastic core-spun yarn.

[0053] Performance test data: Breaking strength 24.5cN / Tex, showing strong tensile resistance; breaking elongation 21.0%, outstanding elastic deformation ability; elastic recovery rate 98%, excellent elasticity after multiple stretching; wear resistance 14,000 times, excellent wear resistance, effectively extending the product life cycle and reducing maintenance costs.

[0054] Embodiment 4

[0055] Pre-twisting of the core yarn layer: polyurethane elastic fiber is used as the core yarn, with a pre-twisting degree of 250T / m, to initially build a stable core yarn structure and enhance the fiber cohesion. The preheating temperature is 45°C and the duration is 9 minutes, which promotes the improvement of the elastic uniformity of the core yarn, the stable molecular thermal movement, and reduces the local performance difference.

[0056] Covering fiber addition: Inner layer: 70% polyester fiber (linear density 28dtex, length 28mm, twist 650 twist / m) and 30% nylon fiber (linear density 22dtex, length 22mm, twist 550 twist / m) blended. The core yarn is coated by fine air jet, and the air flow speed and pressure are precisely controlled to make the fibers evenly distributed and fit. The polyester fiber provides solid support and the nylon fiber guarantees wear resistance; Middle layer: 50% cotton fiber (linear density 18dtex, length 35mm, twist 750 twist / m) and 50% modal fiber (linear density 14dtex, length 38mm, twist 650 twist / m) blended. The first twisted yarn is coated with air jet. The cotton fiber is hygroscopic and soft, and the modal fiber has good elastic transition. The two work together to achieve good stress buffering and ensure uniform and stable coating quality. The outer layer is a blend of 60% cotton fiber (linear density 14dtex, length 38mm, twist 850 twists / m) and 40% polyester fiber (linear density 16dtex, length 32mm, twist 750 twists / m). The second twisted yarn is coated with air jet technology. The cotton fiber gives the yarn a soft touch, and the polyester fiber strengthens the overall structural strength and wear resistance.

[0057] Twisting steps for each layer: First twisting: The core yarn wrapped with the inner layer fiber is twisted for the first time, with a twist degree of 350T / m, so that the inner layer and the core yarn are closely combined, and the twisting equipment parameters are optimized and adjusted to ensure a stable and efficient twisting process; Middle layer covering and secondary twisting: After the middle layer is covered, the secondary twisting is performed, with a twist degree of 450T / m, so that the middle layer is firmly connected with the inner layer and the core yarn to form a stable middle layer structure, and the twisting direction is conducive to stress transfer and dispersion; Outer layer covering and final twisting: After the outer layer is covered, the final twisting is performed, with a twist degree of 550T / m, to build a complete and stable outer layer structure, and the fibers of each layer work synergistically to improve the comprehensive performance of the yarn.

[0058] Post-treatment: Heat setting: Heat setting at 110℃ for 2.5 minutes to optimize the internal fiber structure of the yarn, eliminate internal stress, and improve dimensional stability and shape retention; Oiling treatment: Use silicone oil, the addition amount is 0.8% of the yarn weight, the silicone oil forms a lubricating antistatic film, reduces the friction coefficient and electrostatic adsorption of the yarn, and enhances spinnability and performance; Cooling treatment: Cooling temperature 20-25℃, time 12 minutes, allow the yarn to slowly cool to room temperature, and form a high-performance elastic core-spun yarn structure.

[0059] Performance test data: Breaking strength 21.0cN / Tex, can withstand a certain tensile force; breaking elongation 17.0%, with good elastic deformation ability; elastic recovery rate 95%, still maintains a high elastic recovery level after multiple stretching; wear resistance 11,000 times, good wear resistance, can meet the needs of various application scenarios, and extend the service life of the product.

[0060] Embodiment 5

[0061] Pre-twisting of the core yarn layer: polyurethane elastic fiber is selected as the core yarn material, and the pre-twisting degree is 320T / m, which makes the core yarn structure initially stable and improves the fiber cohesion. The preheating temperature is 52℃ and the duration is 7 minutes, which effectively improves the uniformity of the core yarn elasticity, stabilizes the molecular thermal motion, and reduces local performance fluctuations.

[0062] Coating fiber addition: Inner layer: 70% polyester fiber (linear density 23dtex, length 23mm, twist 720 twist / m) and 30% nylon fiber (linear density 19dtex, length 19mm, twist 620 twist / m) blended. The pre-twisted core yarn is coated with precise air jet technology, the air flow parameters are optimized, the fibers are evenly and tightly coated, the polyester fiber provides strength protection, and the nylon fiber enhances wear resistance; Middle layer: 50% cotton fiber (linear density 14dtex, length 33mm, twist 820 twist / m) and 50% modal fiber (linear density 11dtex, length 36mm, twist 720 twist / m) blended. The yarn after the first twist is evenly coated by air jet. The cotton fiber is hygroscopic and soft, and the modal fiber has excellent elastic recovery. The two work together to achieve effective stress buffering and transition, ensuring the uniformity and stability of the coating; the outer layer is a blend of 60% cotton fiber (linear density 11dtex, length 36mm, twist 920 twists / m) and 40% polyester fiber (linear density 14dtex, length 30mm, twist 820 twists / m). The yarn after the second twist is coated by the air jet process. The cotton fiber gives the yarn a soft texture, and the polyester fiber strengthens the overall structural strength and wear resistance.

[0063] Twisting steps for each layer: First twisting: The core yarn covering the inner layer fiber is twisted for the first time, with a twist degree of 420T / m, so that the inner layer and the core yarn are closely combined, and the twisting equipment is precisely regulated to ensure the twisting quality and efficiency; Middle layer covering and secondary twisting: After the middle layer is covered, the secondary twisting is performed, with a twist degree of 520T / m, so that the middle layer is firmly connected with the inner layer and the core yarn to form a stable middle layer structure, and the twisting direction is coordinated to promote the transfer and dispersion of stress between layers; Outer layer covering and final twisting: After the outer layer is covered, the final twisting is performed, with a twist degree of 620T / m, to build a complete and stable outer layer structure, and each layer of fiber works together to achieve the best performance.

[0064] Post-treatment: Heat setting: Heat setting at 125℃ for 1.8 minutes to adjust the internal fiber structure of the yarn, eliminate the internal stress caused by twisting and covering, and improve the dimensional stability and shape retention of the yarn; Oiling treatment: Use silicone oil, the addition amount is 1.0% of the yarn weight, the silicone oil forms a protective film, reduces the friction coefficient and electrostatic adsorption of the yarn, and improves the spinnability and performance; Cooling treatment: Cooling temperature 25-30℃, time 9 minutes, so that the yarn is cooled steadily to room temperature, forming a high-performance elastic core-spun yarn structure.

[0065] Performance test data: Breaking strength 22.8cN / Tex, can effectively resist tensile force; breaking elongation 19.0%, good elastic deformation performance; elastic recovery rate 96.5%, still maintains excellent elastic recovery ability after multiple stretching; wear resistance 12500 times, excellent wear resistance, can effectively extend the product life cycle and reduce maintenance costs.

[0066] Comparative Example

[0067] The core-spun yarn was prepared by adopting the traditional single-layer covering structure, and compared with the present invention.

[0068] Preparation of coated fibers: Polyester fibers and nylon fibers were mixed in a mass ratio of 7:3, and conventionally spun to prepare coated fibers with a linear density of 25 dtex, a length of 25 mm, and a twist of 700 twists / m.

[0069] Preparation of core-spun yarn: polyurethane elastic fiber is selected as core yarn, and the covering fiber is directly covered and conventionally twisted with a twist degree of 400 T / m.

[0070] Post-treatment: heat setting at 120°C for 2 minutes, using ordinary mineral oil with an addition amount of 1.0%.

[0071] Performance test data: breaking strength 18.0 cN / Tex, lower than the embodiment of the present invention; breaking elongation 14.0%, weak elastic deformation ability; elastic recovery rate 85%, poor elastic recovery after multiple stretching; wear times 8000 times, poor wear resistance, short product service life, and high maintenance cost.

[0072] The elastic core-spun yarns prepared in Example 1, Example 2, Example 3, Example 4, Example 5 and the comparative example were tested for performance, and the results are shown in the following table:

[0073]

[0074] As shown in the table above, in terms of breaking strength, the values ​​of Examples 1 to 5 are all higher than those of the control example. Through the unique multi-layer coating structure and reasonable material matching, the yarn can withstand greater tensile force and the structure is more stable. In terms of elongation at break, the yarn of the present invention can produce greater deformation when stretched, and the synergistic effect of each layer of fiber can effectively disperse stress and recover quickly, and the elastic deformation ability is excellent. The elastic recovery rate further highlights the advantage. The yarn of the present invention can maintain excellent elastic recovery ability, is not easy to relax and deform after long-term use, and performs excellently in scenes with high elasticity requirements. In terms of wear resistance, the efficient wear-resistant protection system jointly constructed by the outer and inner fibers enables the yarn to withstand long-term friction and wear, greatly extending the service life of the product and reducing maintenance costs.

[0075] In summary, the elastic core-spun yarn of the present invention performs excellently in various key performance indicators, has obvious innovation and superiority compared with traditional structures, has broad application prospects and huge market potential in the textile field, and is expected to bring significant performance improvements and breakthroughs to related products.

[0076] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. An elastic core-spun yarn, characterized in that: The elastic core-spun yarn is composed of a core yarn layer and multiple covering layers, specifically: The core yarn layer is composed of polyurethane elastic fiber, which provides inner core support for the core-spun yarn; The multi-layer covering layer is composed of an inner layer, a middle layer and an outer layer, each layer having a different fiber ratio and arrangement direction, and providing graded protection and progressive stress buffering for the core yarn, specifically including: Inner layer: 70% polyester fiber and 30% nylon fiber blended, arranged in radial direction, used to directly protect the core yarn; Middle layer: Blended with 50% cotton fiber and 50% modal fiber, arranged in an oblique direction, providing stress buffering and transition, and restoring the overall elastic properties; Outer layer: 60% cotton and 40% polyester blend, arranged in the machine direction, providing the softness and comfort of the yarn while providing additional abrasion resistance.

2. The elastic core-spun yarn according to claim 1, characterized in that: The inner layer polyester fiber of the coating layer has a linear density of 20-30 dtex, a length of 20-30 mm, and a twist of 600-800 twists / m, and the linear density of the nylon fiber is 15-25 dtex, a length of 18-28 mm, and a twist of 500-700 twists / m, so that the inner layer can fit closely to the core yarn.

3. The elastic core-spun yarn according to claim 1, characterized in that: The length of the middle layer cotton fiber of the coating layer is 25-35mm, the linear density is 12-20dtex, and the twist is 700-900 twists / m. The length of the modal fiber is 30-40mm, the linear density is 10-18dtex, and the twist is 600-800 twists / m to ensure stress buffering and transition effects.

4. The elastic core-spun yarn according to claim 1, characterized in that: The outer cotton fiber of the coating layer has a twist of 800-1000 twists / m, a linear density of 10-15 dtex, and a length of 30-40 mm, and the polyester fiber has a twist of 700-900 twists / m, a linear density of 12-18 dtex, and a length of 25-35 mm.

5. The elastic core-spun yarn according to claim 1, characterized in that: The inner layer thickness of the coating layer accounts for 30%-40% of the total thickness of the multi-layer coating layer, the middle layer thickness accounts for 30%-40%, and the outer layer thickness accounts for 20%-40%.

6. A method for preparing an elastic core-spun yarn, applicable to an elastic core-spun yarn according to any one of claims 1 to 5, characterized in that: The specific steps of the preparation method are: Pre-twisting of the core yarn layer: Select polyurethane elastic fiber as the core yarn material, pre-twist and preheat the core yarn, the twist degree is 200-400T / m, the preheating temperature is 40-60℃, and the preheating time is 5-10 minutes, so that the core yarn has a preliminary structural stability; Adding covering fibers: prepare covering fibers of different layers, and evenly cover the inner covering fibers on the pre-twisted core yarn. The covering method adopts air jetting to evenly spray. First twisting: The core yarn covered with the inner layer fiber is twisted for the first time, with a twist degree of 300-500T / m, so that the inner layer fiber and the core yarn are closely combined to form a stable inner layer structure; Middle layer coating: The middle layer coating fiber is evenly coated on the yarn after the first twisting, and the coating method is the same as the inner layer; Secondary twisting: The yarn covered with the middle layer fiber is twisted twice, with a twist degree of 400-600T / m, so that the middle layer fiber is closely combined with the inner layer fiber and the core yarn to form a stable middle layer structure; Outer layer coating: The outer layer coating fiber is evenly coated on the yarn after secondary twisting, and the coating method is the same as the inner layer and the middle layer; Final twisting: The yarn covered with the outer layer fiber is finally twisted with a twist degree of 500-700T / m, so that the outer layer fiber is closely combined with the middle layer fiber and the core yarn to form a stable outer layer structure; Post-treatment: The yarn is post-treated after final twisting, including heat setting, oiling and cooling.

7. The method for preparing an elastic core-spun yarn according to claim 6, characterized in that: The twisting direction of the pre-twisting of the core yarn layer is the Z direction, and the twisting directions of the first twisting, the second twisting and the final twisting of the covering layer are all the S direction.

8. The method for preparing an elastic core-spun yarn according to claim 6, characterized in that: In the post-treatment process, the temperature and time of heat setting are 100-150° C., the time is 1-3 minutes, the oil agent used in the oiling treatment is silicone oil, and the addition amount of the oil agent is 0.5%-2.0% of the weight of the yarn.

9. The method for preparing an elastic core-spun yarn according to claim 6, characterized in that: In the post-treatment process, the yarn is cooled after heat setting, the cooling temperature is from room temperature to 40° C., and the cooling time is 5-15 minutes to stabilize the structure and performance of the yarn.

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