A thermoplastic polyurethane elastomer foamed yarn, its preparation method and application

Abstract

This invention discloses a thermoplastic polyurethane elastomer foamed yarn, its preparation method, and its applications. The thermoplastic polyurethane elastomer foamed yarn comprises a thermoplastic polyurethane elastomer foamed core and a thermoplastic polyurethane adhesive layer covering the core. The thermoplastic polyurethane elastomer foamed yarn is obtained through a one-step impregnation, foaming, setting, and cooling process using a thermoplastic polyurethane hot melt adhesive. The thermoplastic polyurethane elastomer foamed yarn of this invention possesses excellent properties such as high strength, good hand feel, light weight, and ease of weaving.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic polyurethane elastomer foam materials, specifically to a thermoplastic polyurethane elastomer foam yarn, its preparation method, and its application. Background Technology

[0002] Thermoplastic polyurethane elastomer (TPU) is a semi-crystalline block polymer material prepared by combining diisocyanate, long-chain diol and short-chain diol in a certain proportion through reactive extrusion equipment. It has excellent mechanical properties, heat and chemical resistance, and wear resistance. Due to its special block structure, products with a very wide range of hardness can be obtained by adjusting the proportion of each component.

[0003] TPU yarn is a new type of environmentally friendly textile material. Compared with traditional textile fibers, it has excellent abrasion resistance and bending resistance, high tear strength, easy shaping, environmental friendliness, and recyclability. At the same time, TPU yarn can also improve the strength of the shoe upper, provide strong support, make the shoe upper more shapely, and make it more resistant to abrasion, folding, and puncture, facilitating lightweight design.

[0004] However, current TPU yarns suffer from a stiff feel and heavy weight, limiting their application in areas such as shoe uppers, seat fabrics, and cushioning. Patents CN116770454A and CN116770455A both describe the use of thermoplastic polyurethane as the main component to prepare thermoplastic polyurethane elastomer foam yarns. Compared to traditional TPU yarns, thermoplastic polyurethane elastomer foam yarns have a significantly lower density, are lighter, and have a softer feel. However, their mechanical properties are somewhat reduced, and the presence of micropores on the surface increases roughness, which is detrimental to the weaving of the foam yarn, thus limiting their application. Summary of the Invention

[0005] To address the aforementioned technical problems and shortcomings in this field, the present invention provides a thermoplastic polyurethane elastomer foamed yarn, its preparation method, and its applications. The thermoplastic polyurethane elastomer foamed yarn of the present invention possesses excellent properties such as high strength, good hand feel, light weight, and ease of weaving. The preparation method of the present invention is simple to operate, safe and environmentally friendly, and can be continuously produced.

[0006] The specific technical solution is as follows:

[0007] In a first aspect, the present invention provides a thermoplastic polyurethane elastomer foamed yarn, comprising a thermoplastic polyurethane elastomer foamed core yarn and a thermoplastic polyurethane adhesive layer covering the thermoplastic polyurethane elastomer foamed core yarn.

[0008] The diameter of the thermoplastic polyurethane elastomer foam yarn can be 0.4 to 1.5 mm.

[0009] The thermoplastic polyurethane elastomer foamed yarn can be obtained by one-step impregnation, foaming, shaping, and cooling of thermoplastic polyurethane elastomer yarn impregnated with high-pressure fluid.

[0010] The one-step impregnation and foaming process described in this invention refers to the simultaneous execution of the foaming process and the impregnation process.

[0011] The impregnation can be done using thermoplastic polyurethane hot melt adhesive.

[0012] In some embodiments, the high-pressure fluid is a supercritical fluid.

[0013] The high-pressure fluid may include at least one of nitrogen and carbon dioxide.

[0014] The pressure of the high-pressure fluid can be 5 to 30 MPa.

[0015] The high-pressure fluid impregnated thermoplastic polyurethane elastomer yarn contains 0.5 to 8.0 wt.% of high-pressure fluid.

[0016] The diameter of the thermoplastic polyurethane elastomer yarn can be 0.05 to 0.3 mm, for example, 0.1 mm.

[0017] The thermoplastic polyurethane elastomer yarn can be obtained by thermoplastic polyurethane elastomer extrusion stretching and shaping.

[0018] The Shore hardness of the thermoplastic polyurethane elastomer can be 70-90A, such as 80A, 85A, etc.

[0019] The extrusion temperature can be 150–220°C.

[0020] The thermoplastic polyurethane elastomer yarn impregnated with the high-pressure fluid can be stored at -20 to 10°C (e.g., 0°C) before use, and the weight loss rate of the high-pressure fluid is preferably not higher than 25% (preferably not higher than 20%).

[0021] The high-pressure fluid impregnated thermoplastic polyurethane elastomer yarn is obtained by impregnating the thermoplastic polyurethane elastomer yarn in a high-pressure fluid. The impregnation temperature can be -10 to 50°C. The impregnation time can be 1 to 10 hours.

[0022] In some embodiments, the initial flow temperature of the thermoplastic polyurethane hot melt adhesive is not higher than 120°C, and may be further 90–120°C.

[0023] In some embodiments, the temperature of the one-step impregnation and foaming is 130–180°C.

[0024] In some embodiments, the dwell time for the one-step impregnation and foaming is 10 to 20 seconds.

[0025] The shaping temperature can be 40–60°C, and the time can be 10–20 seconds.

[0026] The shaping process can be hot air shaping.

[0027] The cooling can be spray cooling. The cooling can also be achieved using cooling water. Furthermore, the temperature of the cooling water can be 5–10°C. The cooling time can be 5–10 seconds.

[0028] A constant-speed drawing operation can be added between the shaping and cooling processes. The constant-speed drawing speed can be 3 to 5 m / min.

[0029] The thermoplastic polyurethane elastomer foam core wire may be composed of one or more thermoplastic polyurethanes. The thermoplastic polyurethane adhesive layer may also be composed of one or more thermoplastic polyurethanes. The thermoplastic polyurethanes constituting the thermoplastic polyurethane elastomer foam core wire and the thermoplastic polyurethanes constituting the thermoplastic polyurethane adhesive layer may be completely identical, partially identical, or completely different. The present invention does not particularly limit the raw material composition of these thermoplastic polyurethanes and may use materials commonly used in the art, such as polyols, isocyanates, and chain extenders. The polyols may include at least one of polyester diols, polyether diols, and polycarbonate diols. The isocyanates may include at least one of diphenylmethane-4,4' diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, phenylmethane diisocyanate, and hydrogenated phenylmethane diisocyanate. The chain extenders may include at least one of aliphatic, aromatic, or alicyclic diol compounds.

[0030] In a second aspect, the present invention provides a method for preparing the thermoplastic polyurethane elastomer foamed yarn described in the first aspect, comprising:

[0031] The thermoplastic polyurethane elastomer yarn impregnated with high-pressure fluid is impregnated, foamed, shaped, and cooled in one step to obtain the thermoplastic polyurethane elastomer foamed yarn.

[0032] The impregnation adhesive is a thermoplastic polyurethane hot melt adhesive.

[0033] In the preparation method described in the second aspect, the specific selection and optimization of the technical solution can be made with reference to the content of the first aspect of the present invention.

[0034] In the preparation method described in the second aspect, the feeding speed of the thermoplastic polyurethane elastomer yarn impregnated by high-pressure fluid can be 30-70 mm / s.

[0035] The one-step impregnation and foaming process can be carried out using a one-step impregnation and foaming device.

[0036] In some embodiments, the one-step impregnation and foaming device contains a thermoplastic polyurethane hot melt adhesive liquid. The one-step impregnation and foaming device is provided with a wire feeding guide wheel, a wire guide wheel, a wire unloading guide wheel and a diameter limiter in sequence along the wire feeding direction, and the diameter limiter is positioned higher than the liquid surface of the thermoplastic polyurethane hot melt adhesive liquid.

[0037] The number of guide wheels can be zero or one or more.

[0038] The high-pressure fluid impregnated thermoplastic polyurethane elastomer yarn undergoes both impregnation and foaming processes simultaneously in the thermoplastic polyurethane hot melt adhesive.

[0039] The diameter of the limiting device can be 0.5 to 1.5 mm.

[0040] Thirdly, the present invention provides the application of the thermoplastic polyurethane elastomer foam yarn described in the first aspect in shoe uppers, seat fabrics, cushions, watch straps, thermal insulation shells, shock-absorbing covering shells, and bags.

[0041] Compared with the prior art, the beneficial effects of this invention are as follows:

[0042] The thermoplastic polyurethane elastomer foamed yarn of this invention features a double-layer structure: an inner layer of foamed yarn filaments and an outer layer of thermoplastic polyurethane adhesive. The inner foamed layer provides a good hand feel and significantly reduces plasticity. The outer adhesive layer ensures the strength of the thermoplastic polyurethane elastomer foamed yarn and allows for low-temperature thermoforming. Products woven from this thermoplastic polyurethane elastomer foamed yarn can be manufactured into desired shapes using a low-temperature heat-setting process, while preventing air leakage from the inner foamed yarn filaments. Furthermore, the invention combines the two steps of overmolding and TPU yarn foaming in the preparation of the thermoplastic polyurethane elastomer foamed yarn into a single step, improving production efficiency and reducing energy consumption. In addition, the outer thermoplastic polyurethane adhesive layer reduces the surface roughness of the foamed yarn, minimizing friction between yarns during weaving and improving the continuity and yield of the foamed yarn fabric.

[0043] This invention eliminates the need for the two-step process of foaming followed by impregnation, and avoids the need for secondary heating of the foamed fibers, thus preventing problems such as air leakage or pore collapse of the foamed fibers during the impregnation process. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of a one-step impregnation and foaming device used in this invention. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Operating methods not specifically specified in the following embodiments are generally performed under conventional conditions or as recommended by the manufacturer.

[0046] See Figure 1 A one-step impregnation and foaming device 9 is provided, with an inlet 6 on the bottom side and a heating module 8 on the bottom surface. Molten thermoplastic polyurethane hot melt adhesive enters the one-step impregnation and foaming device 9 through the inlet 6 and is temperature-controlled by the heating module 8. The one-step impregnation and foaming device 9 is equipped with temperature controllers 3 to monitor the temperature of the molten thermoplastic polyurethane hot melt adhesive. There can be one or more temperature controllers 3; in this example, there are two. When there are multiple temperature controllers 3, they can be set at different heights and positions to fully reflect the overall temperature distribution of the molten thermoplastic polyurethane hot melt adhesive within the one-step impregnation and foaming device 9. The temperature controllers 3 can form an interlock control with the heating module 8. The heating module 8 can adjust its heating operation (including on / off switching, heating power adjustment, etc.) based on a comparison between the molten thermoplastic polyurethane hot melt temperature fed back by the temperature controllers 3 and the set temperature. The one-step impregnation and foaming device 9 is equipped with a feeding guide roller 1, a guide roller 7, a retraction guide roller 4, and a diameter limiter 5 arranged sequentially along the yarn feeding direction. The diameter limiter 5 is positioned higher than the liquid level of the thermoplastic polyurethane hot melt adhesive in the one-step impregnation and foaming device 9. The number of guide rollers 7 can be zero or one or more; in this example, there are six. One or more of the feeding guide rollers 1, guide rollers 7, and retraction guide rollers 4 can be partially or completely immersed in the thermoplastic polyurethane hot melt adhesive. The thermoplastic polyurethane elastomer yarn 10, impregnated by high-pressure fluid, advances under the action of the feeding guide rollers 1, guide rollers 7, and retraction guide rollers 4, comes into contact with the thermoplastic polyurethane hot melt adhesive, and completes the impregnation and foaming process simultaneously in the thermoplastic polyurethane hot melt adhesive in one step, finally passing through the diameter limiter 5. The one-step impregnation and foaming device 9 is also equipped with a liquid level limiter 2, which can be one or more; in this example, there are two. The liquid level limiter 2 can provide feedback when the liquid level of the thermoplastic polyurethane hot melt adhesive reaches a preset height, and is used to control the liquid level of the thermoplastic polyurethane hot melt adhesive to be below the limiter 5.

[0047] The one-step impregnation and foaming equipment used below are all as follows Figure 1 The structure shown above.

[0048] Example 1

[0049] The preparation of thermoplastic polyurethane elastomer foamed yarn includes the following steps:

[0050] a. Preparation of thermoplastic polyurethane elastomer yarn primary product of thermoplastic polyurethane A-1.

[0051] b. The initial thermoplastic polyurethane elastomer yarn product is placed in a high-pressure device and impregnated with supercritical fluid (supercritical CO2 fluid) to form an equilibrium state. After impregnation, the thermoplastic polyurethane filament is removed and subjected to low-temperature gas-locking treatment to obtain impregnated thermoplastic elastomer filament. The amount of supercritical fluid dissolved in the thermoplastic elastomer filament is 5.0 wt.%, the low-temperature gas-locking temperature is -20℃, and the weight loss rate of supercritical fluid during the low-temperature gas-locking treatment is not higher than 20%.

[0052] c. The high-pressure fluid-impregnated thermoplastic polyurethane elastomer yarn prepared in step b is loaded onto an unwinding reel, passes through a one-step impregnation and foaming device, a hot air tunnel constant-speed drafting unit, and a spray cooling unit, and is rewound at the other end to obtain a high-strength thermoplastic polyurethane elastomer foamed yarn. During this process, the selection of thermoplastic polyurethane B is listed in Table 1. Thermoplastic polyurethane B-1 is added to the one-step impregnation and foaming device. The one-step impregnation and foaming temperature is 130℃, and the residence time in the device is 20s. The tunnel setting temperature is 60℃, and the residence time is 20s. The constant-speed drafting speed is 3m / min. The cooling water temperature used in the spray cooling unit is 10℃, and the cooling time is 10s. The diameter limiter size is 0.5mm. The performance evaluation of the thermoplastic polyurethane elastomer foamed yarn is listed in Table 3.

[0053] Table 1

[0054]

[0055] The specific preparation process of step a includes:

[0056] A primary product of thermoplastic polyurethane elastomer yarn containing thermoplastic polyurethane A was prepared. According to the components and their molar ratios shown in Table 2, all components of thermoplastic polyurethane A were dried, fed into a twin-screw extruder, melt-extruded, and cooled to obtain thermoplastic polyurethane fiber filaments. These filaments were then wound to obtain the primary product of thermoplastic polyurethane elastomer yarn. The drying was performed by hot air drying, resulting in a moisture content of less than 0.07 wt.%, a winding speed of 2 m / s, and a diameter of 0.10 mm for the primary product of thermoplastic polyurethane elastomer yarn. The molar ratios and characteristics of each component of thermoplastic polyurethane A are listed in Table 2.

[0057] Table 2

[0058]

[0059] Example 2

[0060] The preparation of thermoplastic polyurethane elastomer foamed yarn includes the following steps:

[0061] a. Preparation of the initial product of thermoplastic polyurethane elastomer yarn of thermoplastic polyurethane A-1; the specific process is the same as in Example 1.

[0062] b. The initial thermoplastic polyurethane elastomer yarn product is placed in a high-pressure device and impregnated with supercritical fluid (supercritical CO2 fluid) to form an equilibrium state. After impregnation, the thermoplastic polyurethane filament is removed and subjected to low-temperature gas-locking treatment to obtain impregnated thermoplastic elastomer filament. The amount of supercritical fluid dissolved in the thermoplastic elastomer filament is 5.0 wt.%, the low-temperature gas-locking temperature is -20℃, and the weight loss rate of supercritical fluid during the low-temperature gas-locking treatment is not higher than 20%.

[0063] c. The high-pressure fluid-impregnated thermoplastic polyurethane elastomer yarn prepared in step b is loaded onto an unwinding reel, passes through a one-step impregnation and foaming device, a hot air tunnel constant-speed drafting unit, and a spray cooling unit, and is rewound at the other end to obtain a high-strength thermoplastic polyurethane elastomer foamed yarn. During this process, thermoplastic polyurethane B-1 is added to the one-step impregnation and foaming device. The one-step impregnation and foaming temperature is 150℃, and the residence time in the one-step impregnation and foaming device is 20s. The tunnel setting temperature is 60℃, and the residence time in the tunnel is 20s. The constant-speed drafting speed is 3m / min. The cooling water temperature used in the spray cooling unit is 5℃, and the cooling time is 10s. The diameter limiter size is 1mm. The performance evaluation of the thermoplastic polyurethane elastomer foamed yarn is listed in Table 3.

[0064] Example 3

[0065] The preparation of thermoplastic polyurethane elastomer foamed yarn includes the following steps:

[0066] a. Preparation of thermoplastic polyurethane elastomer yarn primary product of thermoplastic polyurethane A-2; the specific process is the same as in Example 1, the main difference being that the components of thermoplastic polyurethane A-1 in Example 1 are replaced with the components of thermoplastic polyurethane elastomer A-2.

[0067] b. The initial thermoplastic polyurethane elastomer yarn product is placed in a high-pressure device and impregnated with supercritical fluid (supercritical CO2 fluid) to form an equilibrium state. After impregnation, the thermoplastic polyurethane filament is removed and subjected to low-temperature gas-locking treatment to obtain impregnated thermoplastic elastomer filament. The amount of supercritical fluid dissolved in the thermoplastic elastomer filament is 5.0 wt.%, the low-temperature gas-locking temperature is -20℃, and the weight loss rate of supercritical fluid during the low-temperature gas-locking treatment is not higher than 20%.

[0068] c. The high-pressure fluid-impregnated thermoplastic polyurethane elastomer yarn prepared in step b is loaded onto an unwinding reel, passes through a one-step impregnation and foaming device, a hot air tunnel constant-speed drafting unit, and a spray cooling unit, and is rewound at the other end to obtain a high-strength thermoplastic polyurethane elastomer foamed yarn. During this process, thermoplastic polyurethane B-2 is added to the one-step impregnation and foaming device. The one-step impregnation and foaming temperature is 160℃, and the residence time in the one-step impregnation and foaming device is 10s. The tunnel setting temperature is 40℃, and the residence time in the tunnel is 10s. The constant-speed drafting speed is 5m / min. The cooling water temperature used in the spray cooling unit is 5℃, and the cooling time is 5s. The diameter limiter size is 1mm. The performance evaluation of the thermoplastic polyurethane elastomer foamed yarn is listed in Table 3.

[0069] Example 4

[0070] The preparation of thermoplastic polyurethane elastomer foamed yarn includes the following steps:

[0071] a. Preparation of the initial product of thermoplastic polyurethane elastomer yarn of thermoplastic polyurethane A-1; the specific process is the same as in Example 1.

[0072] b. The initial thermoplastic polyurethane elastomer yarn product is placed in a high-pressure device and impregnated with supercritical fluid (supercritical CO2 fluid) to form an equilibrium state. After impregnation, the thermoplastic polyurethane filament is removed and subjected to low-temperature gas-locking treatment to obtain impregnated thermoplastic elastomer filament. The amount of supercritical fluid dissolved in the thermoplastic elastomer filament is 5.0 wt.%, the low-temperature gas-locking temperature is -20℃, and the weight loss rate of supercritical fluid during the low-temperature gas-locking treatment is not higher than 20%.

[0073] c. The high-pressure fluid-impregnated thermoplastic polyurethane elastomer yarn prepared in step b is loaded onto an unwinding reel, passes through a one-step impregnation and foaming device, a hot air tunnel constant-speed drafting unit, and a spray cooling unit, and is rewound at the other end to obtain a high-strength thermoplastic polyurethane elastomer foamed yarn. During this process, thermoplastic polyurethane B-2 is added to the one-step impregnation and foaming device. The one-step impregnation and foaming temperature is 180℃, and the residence time in the one-step impregnation and foaming device is 10s. The tunnel setting temperature is 40℃, and the residence time in the tunnel is 10s. The constant-speed drafting speed is 5m / min. The cooling water temperature used in the spray cooling unit is 5℃, and the cooling time is 5s. The diameter limiter size is 1.5mm. The performance evaluation of the thermoplastic polyurethane elastomer foamed yarn is listed in Table 3.

[0074] Comparative Example 1

[0075] The difference between Comparative Example 1 and Example 1 is that in step c of Comparative Example 1, thermoplastic polyurethane B-1 was not added to the one-step impregnation and foaming device. Instead, 130°C saturated water vapor was used to replace it and entered the one-step impregnation and foaming device from the glue inlet. The other parameters remained unchanged, and thermoplastic polyurethane foamed fibers were obtained. The performance evaluation is listed in Table 3.

[0076] Comparative Example 2

[0077] The difference between Comparative Example 2 and Comparative Example 1 is that the thermoplastic polyurethane foam fiber obtained in Comparative Example 1 is loaded onto an unwinding reel, passes through a one-step impregnation and foaming device, a hot air tunnel constant-speed drafting unit, and a spray cooling unit, and is rewound at the other end to obtain a two-stage impregnated thermoplastic polyurethane elastomer foam yarn. During this process, thermoplastic polyurethane B-1 is added to the one-step impregnation and foaming device. The temperature of the one-step impregnation and foaming is 130℃, and the residence time in the device is 20s. The temperature of the tunnel setting is 60℃, and the residence time in the tunnel is 20s. The constant-speed drafting speed is 3m / min. The cooling water temperature used in the spray cooling unit is 10℃, and the cooling time is 10s. The diameter limiter size is 0.5mm. The performance evaluation of the thermoplastic polyurethane elastomer foam yarn is listed in Table 3.

[0078] Comparative Example 3

[0079] The difference between Comparative Example 3 and Comparative Example 1 is that the thermoplastic polyurethane foam fiber obtained in Comparative Example 1 is loaded onto an unwinding reel, passes through a one-step impregnation and foaming device, a hot air tunnel constant-speed drafting unit, and a spray cooling unit, and is rewound at the other end to obtain a thermoplastic polyurethane elastomer foam yarn simulating secondary impregnation and heating. During this process, 130°C saturated water vapor enters the one-step impregnation and foaming device from the inlet, with a residence time of 20 seconds. The tunnel setting temperature is 60°C, the residence time in the tunnel is 20 seconds, the constant-speed drafting speed is 3 m / min, and the cooling water temperature used in the spray cooling unit is 10°C with a cooling time of 10 seconds. The diameter limiter size is 0.5 mm. The performance evaluation of the thermoplastic polyurethane elastomer foam yarn is listed in Table 3.

[0080] Table 3

[0081]

[0082] The comparison data in Table 3 shows that:

[0083] The thermoplastic polyurethane elastomer foamed yarn of the present invention has superior tensile strength, elongation at break, and tear strength compared to Comparative Example 1, and the surface smoothness of the product is also better. This indicates that the thermoplastic polyurethane elastomer foamed yarn of the present invention has superior mechanical properties compared to the unimpregnated thermoplastic polyurethane elastomer foamed yarn.

[0084] Compared to Comparative Example 2, which uses a two-step impregnation foaming method, the thermoplastic polyurethane elastomer foamed yarn of the present invention achieves lower foam density, higher tensile strength, elongation at break, and tear strength at the same foaming temperature. Furthermore, the surface smoothness of the finished product is better. This indicates that the thermoplastic polyurethane elastomer foamed yarn of the present invention, produced using a one-step impregnation foaming method, has better film coverage and higher foaming efficiency compared to the two-step impregnation foaming method.

[0085] Compared to the polyurethane elastomer foamed yarn prepared in Comparative Example 3, which simulated a secondary impregnation and heating process, the density of the foamed yarn in Comparative Example 1 significantly increased after reheating following foaming. This indicates that during the two-step impregnation foaming process, the original gas in the pores expands due to heat, and the pores cannot contain the increased pressure gas, resulting in gas leakage. Pore shrinkage leads to increased foam fiber density. Comparing the fiber diameters of Comparative Examples 1, 2, and 3 shows that during the two-step impregnation process, the foamed fibers are reheated. Due to heat exchange, the hot melt adhesive initially forms a shell covering the fibers upon contact. As the residence time increases, gas escapes from the pores, and the fibers shrink, causing a tendency for separation between the fibers and the already coated hot melt adhesive. This results in poor coating properties between the two-step hot melt adhesive and the foamed fibers, leading to poor mechanical properties of the two-step impregnated thermoplastic polyurethane elastomer foamed yarn.

[0086] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0087] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A thermoplastic polyurethane elastomer foamed yarn, characterized in that, It includes a thermoplastic polyurethane elastomer foam core wire and a thermoplastic polyurethane adhesive layer covering the thermoplastic polyurethane elastomer foam core wire; The thermoplastic polyurethane elastomer foamed yarn is obtained by one-step impregnation, foaming, shaping, and cooling of thermoplastic polyurethane elastomer yarn impregnated with high-pressure fluid. The impregnation adhesive is a thermoplastic polyurethane hot melt adhesive; The initial flow temperature of the thermoplastic polyurethane hot melt adhesive is not higher than 120°C. The temperature for the impregnation and foaming step is 130~180℃; The dwell time for the one-step impregnation and foaming process is 10-20 seconds; The shaping temperature is 40~60℃, and the time is 10~20 s.

2. The thermoplastic polyurethane elastomer foamed yarn according to claim 1, characterized in that, The high-pressure fluid includes at least one of nitrogen and carbon dioxide; The pressure of the high-pressure fluid is 5~30 MPa; The high-pressure fluid impregnated thermoplastic polyurethane elastomer yarn contains 0.5~8.0 wt.% of high-pressure fluid dissolved in it.

3. The thermoplastic polyurethane elastomer foamed yarn according to claim 1, characterized in that, The diameter of the thermoplastic polyurethane elastomer yarn is 0.05~0.3 mm; The diameter of the thermoplastic polyurethane elastomer foam yarn is 0.4~1.5 mm.

4. The thermoplastic polyurethane elastomer foamed yarn according to claim 1 or 3, characterized in that, The thermoplastic polyurethane elastomer yarn is obtained by thermoplastic polyurethane elastomer extrusion stretching and shaping; The Shore hardness of the thermoplastic polyurethane elastomer is 70~90A.

5. The thermoplastic polyurethane elastomer foamed yarn according to claim 1, characterized in that, The thermoplastic polyurethane elastomer yarn impregnated with high-pressure fluid is stored at -20~10℃ before use, and the weight loss rate of the high-pressure fluid is not higher than 25%.

6. The thermoplastic polyurethane elastomer foamed yarn according to claim 1, characterized in that, The high-pressure fluid impregnated thermoplastic polyurethane elastomer yarn is obtained by impregnating thermoplastic polyurethane elastomer yarn in a high-pressure fluid. The immersion temperature is -10~50℃; The soaking time is 1 to 10 hours.

7. The thermoplastic polyurethane elastomer foamed yarn according to claim 1, characterized in that, The initial flow temperature of the thermoplastic polyurethane hot melt adhesive is 90~120℃.

8. The method for preparing thermoplastic polyurethane elastomer foamed yarn according to any one of claims 1 to 7, characterized in that, include: The thermoplastic polyurethane elastomer yarn impregnated with high-pressure fluid is impregnated, foamed, shaped, and cooled in one step to obtain the thermoplastic polyurethane elastomer foamed yarn. The impregnation adhesive is a thermoplastic polyurethane hot melt adhesive.

9. The preparation method according to claim 8, characterized in that, The one-step impregnation and foaming process is performed using a one-step impregnation and foaming device. The one-step impregnation and foaming device is filled with thermoplastic polyurethane hot melt adhesive liquid. The one-step impregnation and foaming device is arranged in sequence along the wire feeding direction with wire feeding guide wheel (1), wire guide wheel (7), wire unloading guide wheel (4) and diameter limiter (5), and the diameter limiter (5) is positioned higher than the liquid surface of thermoplastic polyurethane hot melt adhesive liquid. The number of guide wheels (7) is one or more; The high-pressure fluid impregnated thermoplastic polyurethane elastomer yarn undergoes both impregnation and foaming processes simultaneously in the thermoplastic polyurethane hot melt adhesive.

10. The application of the thermoplastic polyurethane elastomer foam yarn according to any one of claims 1 to 7 in shoe uppers, seat fabrics, cushions, watch straps, thermal insulation shells, shock-absorbing covering shells, and bags.

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