Composite textile yarn and process for its preparation

Abstract

This invention provides a composite textile yarn and its preparation process, relating to the field of textile yarn technology. The composite textile yarn of this invention consists of three yarns with significantly different boiling water shrinkage rates. The first yarn has the highest boiling water shrinkage rate, the second yarn has a normal shrinkage rate, and the third yarn is an elastic fiber. During high-temperature heat treatment, the first yarn preferentially undergoes directional shrinkage, creating a uniform pulling effect on the second yarn and further fluffing the crimped structure of the second yarn, thereby endowing the composite textile yarn with a three-dimensional porous structure and a rich, full physical structure. Combined with the highly elastic third yarn, a three-dimensional composite textile yarn with a "high-shrinkage skeleton + cotton-like soft core + durable resilience" is obtained.

Description

Technical Field

[0001] This invention belongs to the field of textile yarn technology, and relates to a composite textile yarn and its preparation process. Background Technology

[0002] The textile industry has long faced the technical challenge of the incompatibility between high shrinkage performance and elasticity. High-shrinkage fibers are often produced using low-stretching, low-heat-box processes, resulting in significant internal latent stress. During wet-heat processing, this stress is released violently and randomly. Elastic fibers, on the other hand, possess inherent permanent crimp characteristics, and their wet-heat shrinkage rate and deformation patterns differ greatly from those of high-shrinkage fibers. When high-shrinkage and elastic fibers are directly compounded, subsequent wet-heat processes such as scouring, dyeing, and setting can lead to conflicts due to asynchronous shrinkage and mutual tension of internal stresses, easily causing defects such as claw-like patterns, cloud-like wrinkles, and subtle color variations on the fabric surface. Meanwhile, excessive shrinkage of high-shrinkage fibers can lock the curling and rebound space of elastic fibers, resulting in fabrics that either meet the shrinkage rate but feel stiff and lose elasticity, or retain elasticity but fail to achieve the preset high-shrinkage effect. This seriously restricts the mass production stability and finished product quality of fabrics that combine high-shrinkage texture and high-elasticity comfort. Moreover, existing conventional twisting and heat setting processes cannot reconcile the inherent contradiction between the shrinkage stress of high shrinkage and elastic curling deformation, making it difficult to achieve a synergistic balance between high shrinkage characteristics and high elasticity. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a composite textile yarn and its preparation process.

[0004] The technical solution of the present invention is as follows:

[0005] A composite textile yarn is composed of a first yarn, a second yarn, and a third yarn. The boiling water shrinkage rate of the first yarn is 35-70%; The second yarn has a boiling water shrinkage rate of 2-15%; The third yarn is an elastic fiber with a boiling water shrinkage rate of no more than 10%. The first yarn and the second yarn are each selected from POY.

[0006] Preferably, the difference between the boiling water shrinkage rate of the first yarn and the boiling water shrinkage rate of the second yarn is not less than 30%.

[0007] Preferably, the first yarn has a breaking elongation of 130±5% at 25°C; The second yarn has a breaking elongation of 105±5% at 25°C.

[0008] More preferably, the first yarn has a thermal stretching ratio of 1.2-1.35 times and a thermal stretching temperature that is 25-40°C higher than the glass transition temperature of the first yarn.

[0009] More preferably, the second yarn has a heat stretching ratio of 1.5-1.6 times and a heat stretching temperature of 160-175°C.

[0010] Preferably, the first yarn and the second yarn are each selected from fully dull POY.

[0011] Preferably, the F-number of the second yarn and the F-number of the third yarn are each not less than 72; The first yarn and the second yarn are each made of PET, and the third yarn is made of PTT.

[0012] Preferably, the first yarn and the second yarn are combined and then combined with the third yarn to obtain the composite textile yarn.

[0013] A method for preparing a composite textile yarn according to any of the above embodiments, wherein the first yarn is twisted by S to obtain an A yarn; The second yarn is twisted in a Z-shape to obtain yarn B; The A yarn and the B yarn are connected by a network nozzle and then subjected to high-temperature shrinkage treatment to obtain a composite yarn core; The third yarn is stretched by rollers and then combined with the composite yarn core to obtain the composite textile yarn.

[0014] Preferably, the temperature for the high-temperature shrinkage treatment is 170-220℃; The roller stretching ratio is 1.02-1.04.

[0015] The beneficial effects of this invention are: the composite textile yarn of this invention constructs a three-dimensional composite structure of "high shrinkage skeleton + cotton-like soft core + long-lasting resilience", which fundamentally avoids the conflict in subsequent dyeing and finishing caused by the large difference in shrinkage rate between high shrinkage fiber and elastic fiber, and effectively solves the industry pain point that high shrinkage and high elasticity of textile yarn cannot coexist. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the preparation process of the composite textile yarn in Example 1.

[0017] Figure 2 This is a schematic diagram of the structure of the composite textile yarn obtained in Example 1; Wherein, 1-first yarn, 2-second yarn, 3-third yarn. Detailed Implementation

[0018] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0019] On the one hand, the present invention proposes a composite textile yarn, which is composed of a first yarn, a second yarn and a third yarn; The boiling water shrinkage rate of the first yarn is 35-70%; The boiling water shrinkage rate of the second yarn is 2-15%; The third yarn is an elastic fiber with a boiling water shrinkage rate of no more than 10%. The first and second yarns are selected separately from POY.

[0020] In this invention, the composite textile yarn is composed of a first yarn, a second yarn, and a third yarn. The first yarn has a high boiling water shrinkage rate and preferentially undergoes directional shrinkage during hot box treatment, releasing latent stress and forming a uniform pulling effect on the second yarn with a normal boiling water shrinkage rate. This further fluffs up the crimped structure of the second yarn, giving the composite textile yarn a three-dimensional pore structure and a rich and full physical structure. After being combined with the elastic fiber third yarn, it forms a composite textile yarn with a three-dimensional composite structure of "high shrinkage skeleton + cotton-like soft core + long-lasting resilience".

[0021] In the subsequent dyeing and finishing process, the first yarn releases secondary latent stress, which makes the composite yarn even more fluffy. The second yarn provides a delicate cotton-like texture and fabric stability, while the third yarn continuously provides soft elasticity. The deformation rhythm of the three yarns is highly coordinated, ultimately achieving a composite yarn that combines high fluffiness, a soft and cotton-like feel, and excellent tensile recovery performance. This effectively solves the industry pain point that the high shrinkage and elasticity of traditional yarns cannot coexist.

[0022] For example, the boiling water shrinkage rate of the first yarn can be 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, etc. Further, the boiling water shrinkage rate of the first yarn can be 45-60%. If the boiling water shrinkage rate of the first yarn is high, its strength is low, and it is prone to breakage during subsequent stretching and other processes. The boiling water shrinkage rate of the second yarn can be 2%, 5%, 7%, 8%, 10%, 12%, 15%, etc., and the boiling water shrinkage rate of the third yarn can be 3%, 5%, 7%, 10%, etc.

[0023] In this invention, the boiling water shrinkage rate is tested according to the method of GB / T 6505-2017 "Test Method for Heat Shrinkage Rate of Chemical Fiber Filaments".

[0024] In some embodiments, the difference between the boiling water shrinkage rate of the first yarn and the boiling water shrinkage rate of the second yarn is not less than 30%. The first yarn and the second yarn exhibit significant differences in shrinkage properties. During the hot box treatment, the first yarn preferentially undergoes directional shrinkage, creating a uniform tension on the second yarn, further fluffing the crimped structure of the second yarn, thereby imparting a three-dimensional porous and rich physical structure to the composite textile yarn. For example, the difference between the boiling water shrinkage rate of the first yarn and the boiling water shrinkage rate of the second yarn can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc.

[0025] In some embodiments, the breaking elongation of the first yarn at 25°C is 130±5%; The breaking elongation of the second yarn at 25°C is 105±5%.

[0026] In some embodiments, the hot stretching ratio of the first yarn is 1.2-1.35 times, and the hot stretching temperature is 25-40°C higher than the glass transition temperature of the first yarn.

[0027] The heat stretch ratio of the first yarn is much lower than the conventional heat stretch ratio (around 1.7 times), and the heat stretching temperature is also significantly lower than the conventional heat stretching temperature (generally 160-170℃). This is considered ultra-low stretching, meaning the fiber macromolecules are almost not straightened, retaining more of the original orientation, less axial orientation, and lower crystallinity, resulting in high latent shrinkage stress. The heat stretching temperature of the first yarn is near the critical softening temperature, allowing for stretching and false twisting processes, and is considered ultra-low stretching. For example, the glass transition temperature (Tg) of polyester is generally 67-81℃, so the heat stretching temperature of the first yarn could be 95-120℃, or even further, 100-105℃.

[0028] In some embodiments, the second yarn has a heat stretching ratio of 1.5-1.6 times and a heat stretching temperature of 160-175°C. The second yarn, using the aforementioned heat stretching process, achieves high-temperature setting, allowing for axial orientation and crystallization while avoiding excessive orientation and crystallization. The second yarn maintains a suitable boiling water shrinkage rate and forms a difference in boiling water shrinkage rate compared to the first yarn.

[0029] In some embodiments, the first yarn and the second yarn are individually selected from fully matte POY. Fully matte POY can achieve a uniform matte texture while improving dyeing performance and hiding power, resulting in higher quality composite textile yarns.

[0030] In some embodiments, the F number of the second yarn and the F number of the third yarn are each not less than 72; The first and second yarns are made of PET, and the third yarn is made of PTT.

[0031] For example, the F number of the second yarn can be 72, 96, 144, etc. Furthermore, the F number of the second yarn can be 144, and the F number of the third yarn can be 72.

[0032] In some embodiments, the first yarn and the second yarn are compounded together and then compounded together with the third yarn to obtain a composite textile yarn.

[0033] The first and second yarns are first combined. During the hot box treatment, the first yarn, due to its lower crystallinity, preferentially undergoes directional shrinkage and exerts a uniform pulling effect on the second yarn, further fluffing up the crimped structure of the second yarn. This results in a composite yarn with a three-dimensional porous structure and a rich, full physical structure. After the first and second yarns are combined, they are then combined with a third yarn. This allows the elastic properties of the third yarn to be synergistically utilized, resulting in a composite yarn with a three-dimensional composite structure of "high-shrinkage skeleton + cotton-like soft core + durable resilience".

[0034] On the other hand, the present invention also proposes a method for preparing composite textile yarn according to any of the above embodiments, wherein the first yarn is twisted by S to obtain the A yarn; The second yarn is twisted by Z to obtain yarn B; Yarn A and yarn B are connected through a network nozzle and then subjected to high-temperature shrinkage treatment to obtain a composite yarn core. The third yarn is stretched by rollers and then combined with the composite yarn core to obtain the composite textile yarn of the present invention.

[0035] In some embodiments, the temperature for high-temperature shrinkage treatment is 170-220°C; The roller stretching ratio is 1.02-1.04.

[0036] Due to the low stretching ratio and low stretching temperature process, the first yarn cannot form a stable crystalline structure and has low crystallinity. A large number of polymer segments are "frozen" in a high-energy straightening conformation, storing significant residual orientation stress internally. In this invention, when preparing the composite textile yarn, the first and second yarns are respectively subjected to S-twist and Z-twist, then passed through a network nozzle and undergo high-temperature shrinkage treatment to obtain the composite yarn core. During the high-temperature shrinkage treatment, the mobility of the polymer segments in the amorphous region of the first yarn is significantly enhanced. The originally bound polymer segments can overcome intermolecular forces through thermal motion, achieving a shrinkage rate of 40%-60%. The second yarn has already undergone high-temperature setting, resulting in a lower shrinkage rate during high-temperature shrinkage treatment, for example, 3-7%. The high-temperature shrinkage treatment causes the first yarn to preferentially undergo directional shrinkage, forming a uniform pulling effect on the second yarn and creating a complementary network structure. It also promotes further fluffing of the second yarn's crimped structure, thereby endowing the composite textile yarn with internal three-dimensional pores and a rich, full physical structure. After the third yarn is stretched by the rollers, it is combined with the composite yarn core to obtain the composite textile yarn of the present invention with a three-dimensional composite structure of "high shrinkage skeleton + cotton-like soft core + durable elasticity".

[0037] The temperatures for the aforementioned high-temperature shrinkage treatment can be 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, etc., and further, the high-temperature shrinkage treatment temperature can be 190-220℃. The roller stretching ratio can be 1.02, 1.03, 1.04, etc.

[0038] The technical solutions of the present invention will be further described and explained below with reference to various embodiments.

[0039] Example 1 The preparation process of the composite textile yarn in this embodiment is as follows: Figure 1 As shown.

[0040] The original yarn (polyester) of the first yarn has a breaking elongation of 130% at 25℃. After passing through roller W1.1, it is subjected to a low-temperature and low-elongation treatment at a stretch ratio of 1.3 times by passing through a hot roller at 100℃ to obtain the first yarn. The boiling water shrinkage rate is measured to be 52%. The first yarn is a fully dull POY.

[0041] The original yarn (polyester) of the second yarn has a breaking elongation of 105% at 25℃. After passing through roller W1.0, it is heated in a 170℃ heating box with a stretch ratio of 1.5 and then subjected to high-temperature setting treatment. After passing through a cooling plate, the second yarn is obtained. The boiling water shrinkage rate is measured to be 8%. The second yarn is a fully dull F144 low elongation POY.

[0042] The first yarn enters the S-twist through the rotating ceramic part, and the second yarn enters the Z-twist. They both pass through roller W2 and then through the mesh nozzle (light mesh, fastness about 60%, 80 nodes / meter). After exiting, they pass through roller W2X and then enter the 190℃ lower heating box for high-temperature shrinkage to obtain the composite yarn core.

[0043] The third yarn's raw yarn (F72 T400 elastic fiber, PPT material) passes through roller W1.2 with a stretch ratio of 1.02, then through a fixed ceramic piece and into a fixed yarn guide. It then passes through a temperature-free bypass (no heating, room temperature) and is meshed with the composite yarn core through a mesh nozzle (air pressure 2.2 bar). After meshing, it passes through rollers W3 and W4 respectively, and is wound up to obtain the composite textile yarn.

[0044] A schematic diagram of the composite textile yarn obtained in this embodiment is attached. Figure 2 As shown, the first yarn shrinks significantly when heated, becoming shorter and less curled; the second yarn, due to the shrinkage of the first yarn, exhibits a more pronounced arc diameter; the third yarn, being an elastic fiber, curls like a sawtooth with distinct folds, resembling a spring spiral (see attached image). Figure 2 (The image is represented by a straight line).

[0045] Comparative Example 1 The difference between this comparative example and Example 1 is that in Example 1, the temperature of the hot roller during the hot stretching of the first yarn was adjusted from 100°C to 160°C. The remaining steps remained unchanged. The boiling water shrinkage rate of the first yarn was measured to be 32%.

[0046] Comparative Example 2 The difference between this comparative example and Example 1 is that in Example 1, the temperature of the hot roller during the hot stretching of the first yarn was adjusted from 100°C to 160°C, and the stretching ratio was adjusted from 1.3 times to 1.7 times. The remaining steps remained unchanged. The boiling water shrinkage rate of the first yarn was measured to be 24%.

[0047] Example 2 The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the raw yarn of the first yarn, after passing through roller W1.1, is adjusted to a stretch ratio of 1.2 by a 100°C hot roller at a stretch ratio of 1.3. The remaining steps remain unchanged. The boiling water shrinkage rate of the first yarn was measured to be 67%.

[0048] Example 3 The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the temperature of the hot roller during the hot stretching of the first yarn was adjusted from 100℃ to 105℃. The remaining steps remained unchanged. The boiling water shrinkage rate of the first yarn was measured to be 45%.

[0049] Example 4 The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the stretch ratio of the second yarn's raw yarn when passing through the heating box was adjusted from 1.5 to 1.6. The measured boiling water shrinkage rate of the second yarn was 5%.

[0050] Example 5 The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the temperature of the hot roller during the hot stretching of the first yarn was adjusted from 100℃ to 105℃, and the stretching ratio of the second yarn during its passage through the upper heating box was adjusted from 1.5 to 1.6. The boiling water shrinkage rate of the first yarn was measured to be 45%, and the boiling water shrinkage rate of the second yarn was 21%.

[0051] Composite textile yarn performance testing Boiling water shrinkage rate: according to the method of GB / T 6505-2017 "Test method for heat shrinkage rate of chemical fiber filament".

[0052] Breaking strength: According to GB / T 3916-2013 "Determination of breaking strength and elongation at break of single yarn in packaged textiles".

[0053] Loft: Refer to the method in FZ / T 5009.4-2019 "Test Method for Loft and Elasticity of Hollow Polyester Staple Fiber". Take 30g of the sample after boiling water treatment and place it in a fixed cross-section volume. Apply standard weight pressure (100g) and let it stand for 30s. Calculate the volume of the yarn under pressure and calculate the loft. Loft = Volume under pressure / 30g.

[0054] The results are shown in Table 1 below.

[0055] Table 1

[0056] Therefore, as can be seen from the data in Table 1 above, the composite textile yarn of the present invention has a high shrinkage rate, good mechanical strength and bulkiness, and combines high shrinkage and high elasticity.

[0057] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A composite textile yarn, characterized in that, It is composed of a first yarn, a second yarn, and a third yarn; The boiling water shrinkage rate of the first yarn is 35-70%; The second yarn has a boiling water shrinkage rate of 2-15%; The third yarn is an elastic fiber with a boiling water shrinkage rate of no more than 10%. The first yarn and the second yarn are each selected from POY.

2. The composite textile yarn according to claim 1, characterized in that, The difference between the boiling water shrinkage rate of the first yarn and the boiling water shrinkage rate of the second yarn is not less than 30%.

3. The composite textile yarn according to claim 1, characterized in that, The first yarn has a breaking elongation of 130±5% at 25°C; The second yarn has a breaking elongation of 105±5% at 25°C.

4. The composite textile yarn according to claim 3, characterized in that, The first yarn has a hot stretching ratio of 1.2-1.35 times and a hot stretching temperature that is 25-40°C higher than the glass transition temperature of the first yarn.

5. The composite textile yarn according to claim 3, characterized in that, The second yarn has a heat stretching ratio of 1.5-1.6 times and a heat stretching temperature of 160-175℃.

6. The composite textile yarn according to claim 1, characterized in that, The first yarn and the second yarn are each selected from fully dull POY.

7. The composite textile yarn according to claim 1, characterized in that, The F-number of the second yarn and the F-number of the third yarn are each not less than 72; The first yarn and the second yarn are each made of PET, and the third yarn is made of PTT.

8. The composite textile yarn according to claim 1, characterized in that, The first yarn and the second yarn are combined and then combined with the third yarn to obtain the composite textile yarn.

9. A method for preparing the composite textile yarn according to any one of claims 1-8, characterized in that, The first yarn is twisted by S to obtain yarn A; The second yarn is twisted in a Z-shape to obtain yarn B; The A yarn and the B yarn are connected by a network nozzle and then subjected to high-temperature shrinkage treatment to obtain a composite yarn core; The third yarn is stretched by rollers and then combined with the composite yarn core to obtain the composite textile yarn.

10. The method for preparing composite textile yarn according to claim 9, characterized in that, The temperature for the high-temperature shrinkage treatment is 170-220℃; The roller stretching ratio is 1.02-1.04.

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