A three-component double-helix fatigue-resistant elastic yarn and its preparation method and application

Abstract

The present invention belongs to the field of textile material science and technology, and relates to a three-component double-helix fatigue-resistant elastic yarn and its preparation method and application. The three-component double-helix fatigue-resistant elastic yarn includes a core yarn, an inner covering yarn and an outer covering yarn, the core yarn is an elastic yarn, and the inner covering yarn is formed by twisting two PTT / PET parallel composite fibers with different finenesses; in the PTT / PET parallel composite fibers, the PTT component and the PET component are both semicircular; the fineness of the two PTT / PET parallel composite fibers with different finenesses is 30D and 50D respectively; the twist coefficient of the twisting is 300-400; the preparation method is: first prepare the inner covering yarn, and then sequentially cover the inner covering yarn and the outer covering yarn on the surface of the core yarn; the application is to prepare pressure therapy textiles, and the obtained pressure therapy textiles have both high elasticity and fatigue resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of textile material science and technology, and relates to a three-component double-helix fatigue-resistant elastic yarn and a preparation method and application thereof. Background Art

[0002] Pressure therapy, as a non-invasive physical therapy, has the unique advantage of avoiding the side effects of drug therapy and the new trauma caused by surgery, providing patients with a safe, effective and non-invasive treatment option. This therapy is widely used in the prevention and inhibition of hypertrophic scars after burns, as well as in the treatment of various diseases such as venous hypertension, varicose veins, edema, post-thrombotic syndrome, lower limb venous ulcers and lymphedema. Its core principle is to apply appropriate pressure on the skin surface to achieve therapeutic effects such as promoting blood circulation, reducing edema, and inhibiting scar hyperplasia.

[0003] Currently, pressure therapy mainly uses bandage pressure therapy, manual drainage, and pressure fabric therapy. Among them, bandage pressure therapy is low-cost, but it requires professional skills and there is a risk of skin damage due to improper binding. Manual drainage is difficult to popularize due to limited resources and high prices. Pressure fabric therapy is widely popular in daily life for its convenience.

[0004] The pressure therapy textiles used in pressure fabric therapy, such as compression stockings, are not only easy to put on and take off, but also have good breathability and comfort. Patients can wear them for a long time or even all day without obvious discomfort. In addition, most pressure therapy textiles are easy to clean and maintain, and patients can easily carry out daily cleaning work to maintain the hygiene and functionality of the fabric.

[0005] High elasticity and fatigue resistance are particularly important for compression therapy textiles. High elasticity ensures that compression therapy textiles can closely fit the body curves, adapt to various movement states, provide uniform and effective pressure distribution, and thus optimize the treatment effect. At the same time, fatigue resistance ensures that compression therapy textiles can still maintain their shape and pressure characteristics after repeated use, extending their service life and stabilizing the treatment effect.

[0006] Patent application CN112442770A discloses an innovative elastic composite yarn coating process for compression stockings. This process successfully combines the spandex core yarn with the nylon outer layer through fine raw material winding and double-layer nylon coating technology to form an elastic composite yarn with excellent strength and appearance. However, the elastic composite yarn for compression stockings produced by this patent still has obvious deficiencies in fatigue resistance. Considering that pressure therapy textiles usually need to be worn for a long time (about 23 hours a day), the yarn is prone to stress relaxation under continuous tension, resulting in the gradual attenuation of fabric pressure, which in turn affects the effect of pressure therapy. This stress relaxation phenomenon is due to the hysteresis characteristics of elastomeric yarns under constant deformation conditions. Specifically, after the elastomeric yarn remains in a stretched state for a long time, its internal stress will gradually release, resulting in the gradual weakening of the pressure applied by the fabric. This phenomenon is called stress relaxation, which is a manifestation of the hysteresis characteristics of elastomeric materials under constant deformation.

[0007] Therefore, it is of great significance to develop an elastic yarn with both high elasticity and fatigue resistance. Summary of the invention

[0008] The purpose of the present invention is to solve the problems existing in the prior art and to provide a three-component double-helix fatigue-resistant elastic yarn and a preparation method and application thereof.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A three-component double-helix fatigue-resistant elastic yarn comprises a core yarn, an inner covering yarn and an outer covering yarn, wherein the core yarn is an elastic yarn, and the inner covering yarn is formed by twisting two PTT / PET parallel composite fibers of different finenesses; in the PTT / PET parallel composite fibers, both the PTT component and the PET component are semicircular; the finenesses of the two PTT / PET parallel composite fibers of different finenesses are 30D and 50D respectively; and the twist coefficient of the twisting is 300-400.

[0011] The three-component double-helix fatigue-resistant elastic yarn of the present invention has excellent fatigue resistance, that is, its stress drop rate is low under the condition of long-term constant elongation, which is a mechanical property urgently needed by pressure fabrics and can ensure its therapeutic effect. The main reason is that the inner covering yarn of the present invention is twisted by two PTT / PET parallel composite fibers of different fineness.

[0012] PTT / PET parallel composite fiber is different from general elastic fiber. Its elasticity is determined by its material molecular structure and its macroscopic physical structure (three-dimensional spiral structure), which makes it have good structural stability when repeatedly stretched. After multiple cycles of stretching (200 times), it can still maintain an elastic recovery rate of up to 98%.

[0013] After the yarn formed by twisting two PTT / PET parallel composite fibers of different fineness is used as the inner covering yarn to be coated on the core yarn, the spiral structure formed by the inner covering yarn itself during the twisting process of the two PTT / PET parallel composite fibers of different fineness (referred to as the internal spiral structure) is combined with the spiral structure generated when the core yarn is coated and wound (referred to as the external spiral structure), together forming a unique double spiral structure, which can make the yarn produce a step-by-step stretching effect during the stretching process, and the step-by-step stretching of the yarn can significantly reduce the stress relaxation rate of the yarn. The stretching process is as follows:

[0014] (1) Under the action of external force, the external spiral structure begins to be stretched. At this time, the yarn itself is not fully stretched, and the wrapped spiral angle is large. Once the external force is removed, the yarn can quickly return to its original state, showing good elastic recovery ability;

[0015] (2) As the external force gradually increases, the external helical structure continues to stretch, while the helical angle of the coating gradually decreases. When this change reaches a certain extent, the internal helical structure begins to stretch. At this time, the inner coating yarn is in a prestressed state due to the existence of twist. This state makes the inner coating yarn exhibit higher rigidity, higher elastic modulus and lower elongation.

[0016] (3) As the stretching proceeds, the fibers inside the inner covering yarn will gradually be straightened from the equilibrium state, the twist will gradually be released, the friction between the fibers will decrease, and the inner covering yarn will begin to stretch. During the stretching process, there will be interaction forces (such as friction, cohesion, etc.) between different PTT / PET parallel composite fibers, which can significantly improve the strength of the inner covering yarn on the one hand, and help the inner covering yarn maintain its structural integrity on the other hand;

[0017] (4) When the external force is removed, the yarn will shrink due to the elastic recovery force of the internal fibers.

[0018] In summary, the inner covered yarn formed by twisting two PTT / PET parallel composite fibers of different finenesses enhances the overall elastic properties of the yarn and significantly reduces the stress relaxation phenomenon, thereby improving the fatigue resistance of the pressure fabric.

[0019] In addition, the inner covering yarn is formed by twisting two PTT / PET parallel composite fibers with different finenesses, which is also conducive to fully exerting the mechanical properties of the PTT / PET parallel composite fibers.

[0020] As the preferred technical solution:

[0021] In the three-component double-helix fatigue-resistant elastic yarn as described above, in the PTT / PET parallel composite fiber, the mass ratio of the PTT component to the PET component is 40-60:60-40.

[0022] As described above, the three-component double-helix fatigue-resistant elastic yarn, the core yarn is spandex yarn or rubber yarn, the fineness of the core yarn is selected according to the required fabric pressure level, when the fabric pressure level is level I, the fineness of the core yarn is 360D, when the fabric pressure level is level II, the fineness of the core yarn is 420D, when the fabric pressure level is level III, the fineness of the core yarn is 560D.

[0023] The three-component double-helix fatigue-resistant elastic yarn as described above, the outer covering yarn is nylon filament or silk, and the fineness is 50-90D.

[0024] As described above, a three-component double-helix fatigue-resistant elastic yarn, the inner covering yarn is covered on the core yarn in a Z-twist manner and the twist t1 is 700-900 T / m, the outer covering yarn is covered on the core yarn in an S-twist manner and the twist t2 is 0.7t1-0.9t1, the twist indicates the degree of covering of the core yarn by the covering yarn layer, the size of the twist determines the strength and elongation of the covering yarn and the feel of the yarn, and the ratio of t2 to t1 determines the strength, elongation and feel of the yarn.

[0025] As described above, the three-component double helix fatigue-resistant elastic yarn has a stress relaxation rate of 4.439-9.453% (about 33% lower than that of commercial nylon coated yarn), an elastic recovery rate of 79.428-95.631% (about 15% higher than that of commercial nylon coated yarn), and a breaking strength of 5.356-10.277 cN / tex (about 7% higher than that of commercial nylon coated yarn).

[0026] CN101942723A discloses a three-component composite yarn and a manufacturing method thereof, wherein the yarn is composited with an inner core yarn (5%-30%) and an outer staple fiber (70%-95%), wherein the inner core yarn is made of polyester / nylon and spandex after air deformation. However, when the tensile deformation does not exceed 40%, its elastic recovery rate is only 0-12%. The document "Research on Textile Structure and Mechanical Properties of Medical Compression Stockings [D]. Donghua University, 2014." points out that the stress relaxation rate of the coated yarn is relatively high, ranging from 24% to 47.03%, which may affect the pressure effect of long-term use. By comparison, it can be seen that the stress relaxation rate of the three-component double-helix fatigue-resistant elastic yarn of the present invention is significantly lower than that of the prior art, and the elastic recovery rate is significantly higher than that of the prior art.

[0027] The present invention also provides a method for preparing a three-component double-helix fatigue-resistant elastic yarn as described in any one of the above items, wherein the equipment used includes a lower conveying roller, a feeding roller, a lower pressure roller, a lower hollow spindle, a lower balloon wire guide hook, an upper hollow spindle, an upper balloon wire guide hook, a drafting roller, an upper pressure roller, an upper conveying roller, and a winding roller, and the steps are as follows:

[0028] Two PTT / PET parallel composite fibers with different finenesses are twisted together to obtain an inner covering yarn;

[0029] The core yarn is passed through the lower conveying roller in sequence between the feeding roller and the lower pressing roller and the lower hollow spindle;

[0030] The inner covering yarn and the core yarn are passed through the lower balloon yarn guide hook and the upper hollow spindle in sequence, and then passed through the upper balloon yarn guide hook, the drafting roller and the upper pressure roller in sequence together with the outer covering yarn, and then passed through the upper conveying roller and the winding roller in sequence to obtain the three-component double-helix fatigue-resistant elastic yarn.

[0031] As the preferred technical solution:

[0032] In the method described above, the speed ratio of the drafting roller to the feeding roller (i.e., the drafting multiple of the core yarn) is 4.0-4.8, the elasticity of the coated yarn is mainly provided by the core yarn, and the drafting multiple of the core yarn determines its elasticity and elastic recovery performance. The rotation speed of the lower hollow spindle is 8000-12000rpm, and the rotation speed of the upper hollow spindle is 7000-12000rpm. The spindles are driven by dragon belts to rotate at high speed, and the spindle speed is generally unchanged, which will affect the coated air ring, resulting in changes in the coating tension, thereby affecting the size of the coated yarn twist circle and the uniformity of the twist. The speed ratio of the take-up roller to the drafting roller (i.e., the winding rate) is 0.004-0.006. The larger the winding rate, the greater the tension of the yarn winding, which will cause the coated yarn to increase in plastic deformation during storage and increase the stress relaxation rate.

[0033] The present invention also provides an application of a three-component double-helix fatigue-resistant elastic yarn as described in any of the above items, which is used to prepare pressure therapy textiles. The stress relaxation rate of the pressure therapy textiles is 6.364-9.746%, and the elastic recovery rate is 94.545-97.364%.

[0034] The document "Effect of spandex content on elastic recovery properties of nylon-wrapped spandex knitted fabrics [J]. Shanghai Textile Science and Technology, 2014, 42(02): 35-36+43." deeply explores the effect of spandex content on the elastic properties of nylon-wrapped spandex knitted fabrics. However, it is worth noting that the pressure fabrics tested in this study showed a relatively high stress relaxation rate, with a specific value range of 20.59% to 25.63%. The document "Research on the relationship between spandex dosage and fabric elasticity in nylon-wrapped spandex warp flat velvet elastic fabrics [J]. Knitting Industry, 2000, (03): 15-17+13." studied the relationship between spandex dosage and fabric elasticity. The elastic recovery rate of spandex elastic fabrics can only reach 88.83% at most. By comparison, it can be seen that the stress relaxation rate of the pressure treatment textiles of the present invention is significantly lower than that of the prior art, and the elastic recovery rate is significantly higher than that of the prior art.

[0035] Beneficial effects:

[0036] 1. When preparing the three-component double-helix fatigue-resistant elastic yarn, the present invention adopts an inner covering yarn formed by twisting two PTT / PET parallel composite fibers of different finenesses, and a double-helix structure formed together with the core yarn and the outer covering yarn can release stress step by step during the stretching process, effectively reducing the stress relaxation rate of the yarn and maintaining a high elastic recovery rate.

[0037] 2. The present invention applies three-component double-helix fatigue-resistant elastic yarn to prepare pressure therapy textiles, and the prepared pressure therapy textiles have both high elasticity and fatigue resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic structural diagram of a three-component double-helix fatigue-resistant elastic yarn according to Example 1 of the present invention;

[0039] Figure 2 This is a schematic diagram of preparing a three-component double-helix fatigue-resistant elastic yarn using a HKV141A (II) covered yarn machine in Example 1 of the present invention;

[0040] Figure 3 This is a SEM image of the three-component double-helix fatigue-resistant elastic yarn of Example 1 of the present invention; wherein, Figure 3 a is a plane diagram, Figure 3 b is a cross-sectional view. Figure 3 Figure c is a tensile deformation diagram (stretched to a fixed elongation of 100% with an initial load of 0.1 cN and a loading rate of 50 mm / min);

[0041] Figure 4 This is a stress-strain curve of the three-component double-helix fatigue-resistant elastic yarn of Example 1 of the present invention;

[0042] Figure 5 It is a schematic diagram of the load-elongation curve of the 6th cycle when testing the stress relaxation rate and elastic recovery rate;

[0043] Among them, 1-1 is the core yarn, 1-2 is the inner covering yarn, 1-3 is the outer covering yarn, 2-1 is the lower conveying roller, 2-3 is the feeding roller, 2-4 is the lower pressure roller, 2-5 is the lower hollow spindle, 2-6 is the lower iron copper spindle, 2-7 is the lower balloon wire guide hook, 2-8 is the upper hollow spindle, 2-9 is the upper iron cylinder, 2-10 is the upper balloon wire guide hook, 2-11 is the drawing roller, 2-12 is the winding roller, 2-13 is the yarn cone, 2-14 is the upper conveying roller, and 2-15 is the upper pressure roller. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0045] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0046] Stress relaxation rate and elastic recovery rate: measured according to FZ / T50006 standard. First, the yarn is placed in a standard atmosphere without tension to relax freely and humidify for at least 4 hours (the initial length after humidification is recorded as L 0 , unit: mm); then, 6 stretching and recovery cycles were performed according to the constant elongation load test method, and the load-elongation curve of the 6th cycle was recorded; Figure 5 As shown in the figure, during the sixth cycle test, the yarn is first stretched to a set fixed elongation value (the fixed elongation value is recorded as l 1 , unit: %; the corresponding length is recorded as L 1 , unit: mm). At this time, the tensile curve is segment AB, and the force value recorded at point B is F 1 Then, the yarn length remains constant. Due to the relaxation of internal stress, the load gradually decreases. The curve reaches point C from point B after t1 time (t1 corresponds to the constant elongation time). The force value recorded at this time is F 2 After that, the yarn undergoes a recovery process, and the stretching curve returns to the origin O from point C via point D. After staying at the origin for t2 time (t2 corresponds to the recovery dwell time), the yarn is stretched again until tension appears and reaches point E corresponding to the pre-tension value (0.75 cN). At this time, the elongation is l 2 (The corresponding length is recorded as L 2 , unit: mm); finally, according to the recorded data, the tensile force under a fixed elongation is obtained from the tensile curve, and the retractive force under a fixed elongation is obtained from the recovery curve, and then the elastic recovery rate and stress relaxation rate are calculated; wherein, the gauge length of each cycle is 50 mm, the tensile speed is 50 mm / min, the fixed elongation is 100%, the fixed elongation time is 10 s, and the recovery dwell time is 10 s;

[0047] The elastic recovery rate is calculated as follows:

[0048] ;

[0049] The calculation formula of stress relaxation rate is as follows:

[0050] .

[0051] Breaking strength: measured using a YG061FQ single yarn strength tester in accordance with GB / T 3916-2013 “Determination of breaking strength and elongation of single yarn in packaged textile yarn”; the gauge length is 50 mm and the tensile speed is 50 mm / min.

[0052] Example 1

[0053] A method for preparing a three-component double-helix fatigue-resistant elastic yarn, using a doubling and twisting combined machine and a HKV141A (II) type covering yarn machine, such as Figure 2 As shown, the HKV141A (II) type covered yarn machine includes an upper conveying roller 2-14, a lower conveying roller 2-1, an upper pressure roller 2-15, a lower pressure roller 2-4, a feeding roller 2-3, a lower balloon wire guide hook 2-7, an upper hollow spindle 2-8, an upper balloon wire guide hook 2-10, a drafting roller 2-11, a winding roller 2-12, an upper iron bobbin 2-9, a lower iron bobbin 2-6, a lower hollow spindle 2-5, and a yarn bobbin 2-13. The specific steps are as follows:

[0054] (1) Preparation of raw materials;

[0055] PTT / PET parallel composite fiber a: The specification is 30D / 24F, the mass ratio of PTT component to PET component is 50:50, and both PTT component and PET component are semicircular;

[0056] PTT / PET parallel composite fiber b: the specification is 50D / 32F, the mass ratio of PTT component to PET component is 50:50, and both PTT component and PET component are semicircular;

[0057] Core yarn: spandex yarn, fineness is 560D;

[0058] Outer covering yarn: nylon filament, fineness is 70D;

[0059] (2) First, PTT / PET parallel composite fiber a and PTT / PET parallel composite fiber b are twisted in a twisting machine at a twist coefficient of 350 to obtain inner covered yarn, and then the inner covered yarn is wound onto a lower iron bobbin 2-6 and put on a lower hollow spindle 2-5, and then the outer covered yarn is wound onto an upper iron bobbin 2-9 and put on an upper hollow spindle 2-8;

[0060] (3) The core yarn is passed through the lower conveying roller 2-1, between the feeding roller 2-3 and the lower pressing roller 2-4, and the lower hollow spindle 2-5 in sequence;

[0061] (4) After the inner covering yarn and the core yarn are passed through the lower balloon yarn guide hook 2-7 and the upper hollow spindle 2-8 in sequence, the inner covering yarn and the core yarn are passed through the upper balloon yarn guide hook 2-10, the drafting roller 2-11 and the upper pressure roller 2-15 in sequence, and then are wound on the yarn bobbin 2-13 through the upper conveying roller 2-14 and the winding roller 2-12 in sequence, so as to obtain the three-component double helix fatigue-resistant elastic yarn;

[0062] In steps (2) to (4), the speed ratio of the stretching roller 2-11 to the feeding roller 2-3 is 4, the rotation speed of the upper hollow spindle 2-8 is 7000 rpm, the rotation speed of the lower hollow spindle 2-5 is 10000 rpm, and the speed ratio of the winding roller 2-12 to the stretching roller 2-11 is 0.005.

[0063] like Figure 1 , Figure 3 As shown in FIG. 1 , the three-component double helix fatigue-resistant elastic yarn finally prepared consists of a core yarn 1-1, an inner covering yarn 1-2 and an outer covering yarn 1-3. The inner covering yarn 1-2 is covered on the core yarn 1-1 in a Z-twist manner with a twist of 700 T / m, and the outer covering yarn 1-3 is covered on the core yarn 1-1 in an S-twist manner with a twist of 490 T / m. The stress relaxation rate of the three-component double helix fatigue-resistant elastic yarn is 5.973%, the elastic recovery rate is 93.427%, and the breaking strength (stress-strain curve is shown in FIG. 1 ) ... and the elastic recovery rate is 93.427%. Figure 4 As shown) is 9.373cN / tex.

[0064] A pressure therapy textile is made of the three-component double-helix fatigue-resistant elastic yarn prepared in this embodiment. The tissue structure of the pressure therapy textile is a plain padding tissue with a thickness of 0.746 mm, a warp density of 56 coils / 50 mm, a weft density of 27 coils / 50 mm, a stress relaxation rate of 7.573%, and an elastic recovery rate of 96.836%.

[0065] Comparative Example 1

[0066] A method for preparing an elastic yarn is basically the same as that in Example 1, except that the inner covering yarn is formed by combining PTT / PET parallel composite fiber a (same as in Example 1) and PTT / PET parallel composite fiber b (same as in Example 1).

[0067] The stress relaxation rate of the elastic yarn finally produced was 16.548%, and the elastic recovery rate was 79.394%.

[0068] A pressure therapy textile is basically the same as Example 1, except that it is made of the elastic yarn prepared in this comparative example; the stress relaxation rate of the pressure therapy textile is 20.937%, and the elastic recovery rate is 70.232%.

[0069] Compared with Example 1, the stress relaxation rate of the elastic yarn and the pressure therapy textile in Comparative Example 1 is significantly increased, and the elastic recovery rate is significantly decreased. This is because the inner covering yarn of the elastic yarn in Comparative Example 1 is a combined composite fiber, the yarn has a smaller wrapping force, a loose structure, and reduced stability.

[0070] Comparative Example 2

[0071] An elastic yarn is basically the same as the first embodiment, except that the positions of the inner covering yarn and the outer covering yarn are interchanged.

[0072] The stress relaxation rate of the elastic yarn is 17.384%, the elastic recovery rate is 78.376%, and the breaking strength is 6.539 cN / tex.

[0073] A pressure therapy textile is basically the same as Example 1, except that it is made of the elastic yarn prepared in this comparative example; the stress relaxation rate of the pressure therapy textile is 21.075%, and the elastic recovery rate is 73.866%.

[0074] Compared with Example 1, the stress relaxation rate of the elastic yarn and the pressure therapy textile in Comparative Example 2 increases, the elastic recovery rate decreases, and the breaking strength decreases. This is because the yarn formed by twisting two PTT / PET parallel composite fibers in Comparative Example 2 is located in the outer layer, and is not in direct contact with the core yarn, but is separated by nylon filaments. During the stretching process, it is constrained by the nylon yarn, and the spandex cannot fully exert its elastic properties. Nylon fails to provide strong support, and the breaking strength decreases.

[0075] Comparative Example 3

[0076] A method for preparing a three-component double-helix fatigue-resistant elastic yarn is basically the same as that of Example 1, except that the specification of the PTT / PET parallel composite fiber b is 30D / 24F.

[0077] The stress relaxation rate of the finally obtained three-component double-helix fatigue-resistant elastic yarn is 11.244%, the elastic recovery rate is 87.343%, and the breaking strength is 6.394 cN / tex.

[0078] A pressure therapy textile is basically the same as Example 1, except that it is made of the yarn prepared in this example; the stress relaxation rate of the pressure therapy textile is 12.375%, and the elastic recovery rate is 93.472%.

[0079] Comparative Example 4

[0080] A method for preparing a three-component double-helix fatigue-resistant elastic yarn is basically the same as that of Example 1, except that the specification of the PTT / PET parallel composite fiber a is 50D / 32F.

[0081] The stress relaxation rate of the finally obtained three-component double-helix fatigue-resistant elastic yarn is 10.374%, the elastic recovery rate is 88.329%, and the breaking strength is 9.458 cN / tex.

[0082] A pressure therapy textile is basically the same as Example 1, except that it is made of the yarn prepared in this example; the stress relaxation rate of the pressure therapy textile is 12.434%, and the elastic recovery rate is 94.573%.

[0083] Comparative Example 5

[0084] A method for preparing a three-component double-helix fatigue-resistant elastic yarn is basically the same as in Example 1, except that the inner covering yarn is twisted with three identical PTT / PET parallel composite fibers (the same as the PTT / PET parallel composite fibers a in Example 1) at a twist coefficient of 350.

[0085] The stress relaxation rate of the finally obtained three-component double-helix fatigue-resistant elastic yarn is 11.273%, the elastic recovery rate is 89.344%, and the breaking strength is 10.278 cN / tex.

[0086] A pressure therapy textile is basically the same as Example 1, except that it is made of the yarn prepared in this example; the stress relaxation rate of the pressure therapy textile is 12.374%, and the elastic recovery rate is 90.374%.

[0087] Comparative Example 6

[0088] A method for preparing a three-component double-helix fatigue-resistant elastic yarn is basically the same as in Example 1, except that the inner covering yarn is formed by twisting three identical PTT / PET parallel composite fibers (the same as the PTT / PET parallel composite fibers b in Example 1) with a twist coefficient of 350.

[0089] The stress relaxation rate of the finally obtained three-component double-helix fatigue-resistant elastic yarn is 12.472%, the elastic recovery rate is 88.384%, and the breaking strength is 12.774 cN / tex.

[0090] A pressure therapy textile is basically the same as Example 1, except that it is made of the yarn prepared in this example; the stress relaxation rate of the pressure therapy textile is 12.947%, and the elastic recovery rate is 89.237%.

[0091] Example 2

[0092] A preparation method of a three-component double-helix fatigue-resistant elastic yarn adopts a doubling and twisting combined machine and a HKV141A (II) type covered yarn machine, wherein the HKV141A (II) type covered yarn machine comprises an upper conveying roller, a lower conveying roller, an upper pressure roller, a lower pressure roller, a feeding roller, a lower balloon wire guide hook, an upper hollow spindle, an upper balloon wire guide hook, a drafting roller, a winding roller, an upper iron bobbin, a lower iron bobbin, a lower hollow spindle, a feeding pressure roller, and a yarn bobbin, and the specific steps are as follows:

[0093] (1) Preparation of raw materials;

[0094] PTT / PET parallel composite fiber a: The specification is 30D / 24F, the mass ratio of PTT component to PET component is 50:50, and both PTT component and PET component are semicircular;

[0095] PTT / PET parallel composite fiber b: the specification is 50D / 32F, the mass ratio of PTT component to PET component is 50:50, and both PTT component and PET component are semicircular;

[0096] Core yarn: spandex yarn, fineness is 560D;

[0097] Outer covering yarn: nylon filament, fineness is 70D;

[0098] (2) First, PTT / PET parallel composite fiber a and PTT / PET parallel composite fiber b are twisted in a twisting machine at a twist coefficient of 350 to obtain inner covering yarn, and then the inner covering yarn is wound onto a lower iron bobbin and put on a lower hollow spindle, and then the outer covering yarn is wound onto an upper iron bobbin and put on an upper hollow spindle;

[0099] (3) The core yarn is passed through the lower conveying roller and the space between the feeding roller and the lower pressure roller, and then through the lower hollow spindle;

[0100] (4) The inner covering yarn and the core yarn are passed through the lower balloon yarn guide hook and the upper hollow spindle in sequence, and then the inner covering yarn and the core yarn are passed through the upper balloon yarn guide hook, the drafting roller and the upper pressure roller in sequence, and then are wound on the yarn bobbin through the upper conveying roller and the winding roller in sequence, so as to obtain the three-component double helix fatigue-resistant elastic yarn;

[0101] In steps (2) to (4), the speed ratio of the drafting roller to the feeding roller is 4.4, the rotation speed of the upper hollow spindle is 7000 rpm, the rotation speed of the lower hollow spindle is 10000 rpm, and the speed ratio of the winding roller to the drafting roller is 0.005.

[0102] The final three-component double-helix fatigue-resistant elastic yarn consists of a core yarn, an inner covering yarn and an outer covering yarn. The inner covering yarn is covered on the core yarn in a Z-twist manner with a twist of 800 T / m, and the outer covering yarn is covered on the core yarn in an S-twist manner with a twist of 560 T / m. The stress relaxation rate of the three-component double-helix fatigue-resistant elastic yarn is 4.439%, the elastic recovery rate is 95.631%, and the breaking strength is 10.277 cN / tex.

[0103] A pressure therapy textile is made of the three-component double-helix fatigue-resistant elastic yarn prepared in this embodiment. The tissue structure of the pressure therapy textile is a plain padding tissue with a thickness of 0.734 mm, a warp density of 56 coils / 50 mm, a weft density of 27 coils / 50 mm, a stress relaxation rate of 6.364%, and an elastic recovery rate of 97.364%.

[0104] Example 3

[0105] A preparation method of a three-component double-helix fatigue-resistant elastic yarn adopts a doubling and twisting combined machine and a HKV141A (II) type covered yarn machine, wherein the HKV141A (II) type covered yarn machine comprises an upper conveying roller, a lower conveying roller, an upper pressure roller, a lower pressure roller, a feeding roller, a lower balloon wire guide hook, an upper hollow spindle, an upper balloon wire guide hook, a drafting roller, a winding roller, an upper iron bobbin, a lower iron bobbin, a lower hollow spindle, a feeding pressure roller, and a yarn bobbin, and the specific steps are as follows:

[0106] (1) Preparation of raw materials;

[0107] PTT / PET parallel composite fiber a: The specification is 30D / 24F, the mass ratio of PTT component to PET component is 50:50, and both PTT component and PET component are semicircular;

[0108] PTT / PET parallel composite fiber b: the specification is 50D / 32F, the mass ratio of PTT component to PET component is 50:50, and both PTT component and PET component are semicircular;

[0109] Core yarn: spandex yarn, fineness is 560D;

[0110] Outer covering yarn: nylon filament, fineness is 70D;

[0111] (2) First, PTT / PET parallel composite fiber a and PTT / PET parallel composite fiber b are twisted in a twisting machine at a twist coefficient of 350 to obtain inner covering yarn, and then the inner covering yarn is wound onto a lower iron bobbin and put on a lower hollow spindle, and then the outer covering yarn is wound onto an upper iron bobbin and put on an upper hollow spindle;

[0112] (3) The core yarn is passed through the lower conveying roller and the space between the feeding roller and the lower pressure roller, and then through the lower hollow spindle;

[0113] (4) The inner covering yarn and the core yarn are passed through the lower balloon yarn guide hook and the upper hollow spindle in sequence, and then the inner covering yarn and the core yarn are passed through the upper balloon yarn guide hook, the drafting roller and the upper pressure roller in sequence, and then are wound on the yarn bobbin through the upper conveying roller and the winding roller in sequence, so as to obtain the three-component double helix fatigue-resistant elastic yarn;

[0114] In steps (2) to (4), the speed ratio of the drafting roller to the feeding roller is 4.8, the rotation speed of the upper hollow spindle is 7000 rpm, the rotation speed of the lower hollow spindle is 10000 rpm, and the speed ratio of the winding roller to the drafting roller is 0.005.

[0115] The final three-component double-helix fatigue-resistant elastic yarn consists of a core yarn, an inner covering yarn and an outer covering yarn. The inner covering yarn is covered on the core yarn in a Z-twist manner with a twist of 900 T / m, and the outer covering yarn is covered on the core yarn in an S-twist manner with a twist of 630 T / m. The stress relaxation rate of the three-component double-helix fatigue-resistant elastic yarn is 9.049%, the elastic recovery rate is 91.395%, and the breaking strength is 8.168 cN / tex.

[0116] A pressure therapy textile is made of the three-component double-helix fatigue-resistant elastic yarn prepared in this embodiment. The tissue structure of the pressure therapy textile is a plain padding tissue with a thickness of 0.782 mm, a warp density of 56 coils / 50 mm, a weft density of 27 coils / 50 mm, a stress relaxation rate of 8.375%, and an elastic recovery rate of 95.269%.

[0117] Example 4

[0118] A preparation method of a three-component double-helix fatigue-resistant elastic yarn adopts a doubling and twisting combined machine and a HKV141A (II) type covered yarn machine, wherein the HKV141A (II) type covered yarn machine comprises an upper conveying roller, a lower conveying roller, an upper pressure roller, a lower pressure roller, a feeding roller, a lower balloon wire guide hook, an upper hollow spindle, an upper balloon wire guide hook, a drafting roller, a winding roller, an upper iron bobbin, a lower iron bobbin, a lower hollow spindle, a feeding pressure roller, and a yarn bobbin, and the specific steps are as follows:

[0119] (1) Preparation of raw materials;

[0120] PTT / PET parallel composite fiber a: The specification is 30D / 24F, the mass ratio of PTT component to PET component is 40:60, and both PTT component and PET component are semicircular;

[0121] PTT / PET parallel composite fiber b: specification is 50D / 32F, the mass ratio of PTT component to PET component is 40:60, and both PTT component and PET component are semicircular;

[0122] Core yarn: rubber yarn, fineness is 420D;

[0123] Outer covering yarn: silk, fineness is 50D;

[0124] (2) First, PTT / PET parallel composite fiber a and PTT / PET parallel composite fiber b are twisted in a twisting machine at a twist coefficient of 300 to obtain inner covering yarn, and then the inner covering yarn is wound onto a lower iron bobbin and put on a lower hollow spindle, and then the outer covering yarn is wound onto an upper iron bobbin and put on an upper hollow spindle;

[0125] (3) The core yarn is passed through the lower conveying roller and the space between the feeding roller and the lower pressure roller, and then through the lower hollow spindle;

[0126] (4) The inner covering yarn and the core yarn are passed through the lower balloon yarn guide hook and the upper hollow spindle in sequence, and then the inner covering yarn and the core yarn are passed through the upper balloon yarn guide hook, the drafting roller and the upper pressure roller in sequence, and then are wound on the yarn bobbin through the upper conveying roller and the winding roller in sequence, so as to obtain the three-component double helix fatigue-resistant elastic yarn;

[0127] In steps (2) to (4), the speed ratio of the drafting roller to the feeding roller is 4.4, the rotation speed of the upper hollow spindle is 10000 rpm, the rotation speed of the lower hollow spindle is 12000 rpm, and the speed ratio of the winding roller to the drafting roller is 0.004.

[0128] The final three-component double-helix fatigue-resistant elastic yarn consists of a core yarn, an inner covering yarn and an outer covering yarn. The inner covering yarn is covered on the core yarn in a Z-twist manner with a twist of 800 T / m, and the outer covering yarn is covered on the core yarn in an S-twist manner with a twist of 720 T / m. The stress relaxation rate of the three-component double-helix fatigue-resistant elastic yarn is 8.486%, the elastic recovery rate is 80.473%, and the breaking strength is 5.356 cN / tex.

[0129] A pressure therapy textile is made of the three-component double-helix fatigue-resistant elastic yarn prepared in this embodiment. The tissue structure of the pressure therapy textile is a plain padding tissue with a thickness of 0.738 mm, a warp density of 56 coils / 50 mm, a weft density of 27 coils / 50 mm, a stress relaxation rate of 8.376%, and an elastic recovery rate of 95.347%.

[0130] Example 5

[0131] A preparation method of a three-component double-helix fatigue-resistant elastic yarn adopts a doubling and twisting combined machine and a HKV141A (II) type covered yarn machine, wherein the HKV141A (II) type covered yarn machine comprises an upper conveying roller, a lower conveying roller, an upper pressure roller, a lower pressure roller, a feeding roller, a lower balloon wire guide hook, an upper hollow spindle, an upper balloon wire guide hook, a drafting roller, a winding roller, an upper iron bobbin, a lower iron bobbin, a lower hollow spindle, a feeding pressure roller, and a yarn bobbin, and the specific steps are as follows:

[0132] (1) Preparation of raw materials;

[0133] PTT / PET parallel composite fiber a: The specification is 30D / 24F, the mass ratio of PTT component to PET component is 60:40, and both PTT component and PET component are semicircular;

[0134] PTT / PET parallel composite fiber b: specification is 50D / 32F, the mass ratio of PTT component to PET component is 60:40, and both PTT component and PET component are semicircular;

[0135] Core yarn: rubber yarn, fineness is 360D;

[0136] Outer covering yarn: silk, fineness is 90D;

[0137] (2) First, PTT / PET parallel composite fiber a and PTT / PET parallel composite fiber b are twisted in a twisting machine at a twist coefficient of 400 to obtain inner covering yarn, and then the inner covering yarn is wound onto a lower iron bobbin and put on a lower hollow spindle, and then the outer covering yarn is wound onto an upper iron bobbin and put on an upper hollow spindle;

[0138] (3) The core yarn is passed through the lower conveying roller and the space between the feeding roller and the lower pressure roller, and then through the lower hollow spindle;

[0139] (4) The inner covering yarn and the core yarn are passed through the lower balloon yarn guide hook and the upper hollow spindle in sequence, and then the inner covering yarn and the core yarn are passed through the upper balloon yarn guide hook, the drafting roller and the upper pressure roller in sequence, and then are wound on the yarn bobbin through the upper conveying roller and the winding roller in sequence, so as to obtain the three-component double helix fatigue-resistant elastic yarn;

[0140] In steps (2) to (4), the speed ratio of the drafting roller to the feeding roller is 4.4, the rotation speed of the upper hollow spindle is 12000 rpm, the rotation speed of the lower hollow spindle is 8000 rpm, and the speed ratio of the winding roller to the drafting roller is 0.006.

[0141] The final three-component double-helix fatigue-resistant elastic yarn consists of a core yarn, an inner covering yarn and an outer covering yarn. The inner covering yarn is covered on the core yarn in a Z-twist manner with a twist of 800 T / m, and the outer covering yarn is covered on the core yarn in an S-twist manner with a twist of 560 T / m. The stress relaxation rate of the three-component double-helix fatigue-resistant elastic yarn is 9.453%, the elastic recovery rate is 79.428%, and the breaking strength is 5.734 cN / tex.

[0142] A pressure therapy textile is made of the three-component double-helix fatigue-resistant elastic yarn prepared in this embodiment. The tissue structure of the pressure therapy textile is a plain padding tissue with a thickness of 0.749 mm, a warp density of 56 coils / 50 mm, a weft density of 27 coils / 50 mm, a stress relaxation rate of 9.746%, and an elastic recovery rate of 94.545%.

Claims

1. A three-component double-helix fatigue-resistant elastic yarn, comprising a core yarn, an inner covering yarn and an outer covering yarn, wherein the core yarn is an elastic yarn, characterized in that: The inner covered yarn is formed by twisting two PTT / PET parallel composite fibers of different fineness; in the PTT / PET parallel composite fibers, the PTT component and the PET component are both semicircular; the fineness of the two PTT / PET parallel composite fibers of different fineness are 30D and 50D respectively; the twist coefficient of the twisting is 300-400.

2. The three-component double-helix fatigue-resistant elastic yarn according to claim 1, characterized in that: In the PTT / PET parallel composite fiber, the mass ratio of the PTT component to the PET component is 40-60:60-40.

3. The three-component double-helix fatigue-resistant elastic yarn according to claim 1, characterized in that: The core yarn is spandex yarn or rubber yarn.

4. The three-component double-helix fatigue-resistant elastic yarn according to claim 1, characterized in that: The outer covering yarn is nylon filament or silk with a fineness of 50-90D.

5. The three-component double-helix fatigue-resistant elastic yarn according to claim 1, characterized in that: The inner covering yarn is covered on the core yarn in a Z-twist manner and the twist t1 is 700-900 T / m, and the outer covering yarn is covered on the core yarn in an S-twist manner and the twist t2 is 0.7t1-0.9t1.

6. A three-component double-helix fatigue-resistant elastic yarn according to any one of claims 1 to 5, characterized in that: The stress relaxation rate of the three-component double-helix fatigue-resistant elastic yarn is 4.439-9.453%, the elastic recovery rate is 79.428-95.631%, and the breaking strength is 5.356-10.277 cN / tex.

7. A method for preparing a three-component double-helix fatigue-resistant elastic yarn as claimed in any one of claims 1 to 6, characterized in that: The equipment used includes lower conveying roller, feeding roller, lower pressure roller, lower hollow spindle, lower balloon wire guide hook, upper hollow spindle, upper balloon wire guide hook, drafting roller, upper pressure roller, upper conveying roller, and winding roller. The steps are as follows: Two PTT / PET parallel composite fibers with different finenesses are twisted together to obtain an inner covering yarn; The core yarn is passed through the lower conveying roller in sequence between the feeding roller and the lower pressing roller and the lower hollow spindle; The inner covering yarn and the core yarn are passed through the lower balloon yarn guide hook and the upper hollow spindle in sequence, and then passed through the upper balloon yarn guide hook, the drafting roller and the upper pressure roller in sequence together with the outer covering yarn, and then passed through the upper conveying roller and the winding roller in sequence to obtain the three-component double-helix fatigue-resistant elastic yarn.

8. The method according to claim 7, characterized in that The speed ratio of the drafting roller to the feeding roller is 4.0-4.8, the rotation speed of the lower hollow spindle is 8000-12000rpm, the rotation speed of the upper hollow spindle is 7000-12000rpm, and the speed ratio of the winding roller to the drafting roller is 0.004-0.

006.

9. The use of a three-component double-helix fatigue-resistant elastic yarn according to any one of claims 1 to 6, characterized in that: Used to prepare pressure therapy textiles, the stress relaxation rate of the pressure therapy textiles is 6.364-9.746%, and the elastic recovery rate is 94.545-97.364%.

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