Lightweight high-strength foamed TPU wrap yarn as well as preparation method and application thereof

Abstract

The invention provides a light-weight high-strength foamed TPU wrap yarn and a preparation method and application thereof. The light-weight high-strength foamed TPU wrap yarn comprises a core yarn and a skin layer, the core yarns are high-strength yarns; the skin layer is foamed TPU, and the preparation raw materials of the skin layer comprise TPU and a foaming agent. According to the foamed TPU wrap yarn provided by the invention, the high-strength yarn is combined with a TPU foaming technology, so that the foamed TPU wrap yarn is light in weight; the high-strength yarn is used as the core yarn, the foamed TPU is used as the skin layer to wrap the core yarn, and the core yarn can be kept in the original shape in the high-temperature process and is not damaged; after foaming, the light weight and soft effects can be achieved under the same wire diameter, and the problem that the mechanical property of TPU is reduced after foaming can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of yarns and relates to a lightweight and high-strength foamed TPU coated yarn and a preparation method and application thereof. Background Art

[0002] With technological advancements, the textile industry is placing higher demands on specialty yarns in terms of lightweighting and high strength. Conventional TPU (thermoplastic polyurethane) yarns are known to be stiff and heavy. Foamed TPU yarns significantly reduce density, resulting in a lighter, softer feel, but their mechanical properties are somewhat compromised.

[0003] CN119194861A discloses a foamed yarn and a method for preparing the same. The method comprises the following steps: sizing the yarn in a mixture of a curing agent and a slurry, followed by curing and foaming to obtain the foamed yarn; the slurry comprises a foaming resin and heat-expandable microspheres. In this method, the slurry is cured and foamed to form a foamed coating composed of a flexible resin and an elastic filler on the yarn. The foamed coating improves the softness and resilience of the yarn; the heat-expandable microspheres contained in the foamed coating improve the bulk and air permeability of the yarn after expansion; the curing agent in the foamed coating cross-links with the foamed resin, improving the hydrolysis resistance and flexural resistance of the foamed coating. However, this invention utilizes a microsphere coating process, which is complex and expensive, making it unsuitable for large-scale industrial production.

[0004] Therefore, in this field, it is expected to develop a foamed yarn that is not only lightweight and high-strength, but also has a simple process and low cost, and is suitable for large-scale industrial production. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the object of the present invention is to provide a lightweight, high-strength foamed TPU coated yarn, and a preparation method and application thereof. The present invention combines TPU foaming technology with high-strength yarn, uses a coating process, and produces a skin-core structure, thereby achieving lightweight characteristics at the same wire diameter, and preparing a special yarn with low material consumption, high weaving efficiency, high strength, wear resistance, and light weight. The present invention adds high-strength yarn to the core layer to solve the problem of decreased mechanical properties of foamed TPU, which is conducive to further promoting high-performance special yarns and expanding their scope of application. In addition, the process of the present invention is simple and convenient, the process technology is relatively mature, and the cost is low, making it more suitable for large-scale industrial production.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a lightweight, high-strength foamed TPU coated yarn, wherein the lightweight, high-strength foamed TPU coated yarn comprises a core yarn and a skin layer;

[0008] The core yarn is a high-strength yarn;

[0009] The skin layer is foamed TPU, and the raw materials for preparing the skin layer include TPU and a foaming agent.

[0010] The foamed TPU coated yarn provided by the present invention is lightweight by combining high-strength yarn with TPU foaming technology; the high-strength yarn is used as the core yarn, and the foamed TPU is used as the skin layer to cover the core yarn, which can keep the core yarn in its original shape during high temperature and not be destroyed; after foaming, the same wire diameter can achieve a lightweight and soft effect, which can solve the problem of decreased mechanical properties of TPU after foaming.

[0011] In the present invention, the lightweight high-strength foamed TPU coated yarn refers to the density of the foamed TPU coated yarn being 0.6-0.8 g / cm 3 , for example 0.6 g / cm 3 , 0.65g / cm 3 , 0.7g / cm 3 , 0.75g / cm 3 , 0.8g / cm 3 Etc., high strength refers to the breaking strength of the foamed TPU coated yarn is 5-7cN / dtex.

[0012] Preferably, the high-strength yarn is a yarn having a breaking strength in the range of 5-7 cN / dtex (e.g., 5 cN / dtex, 5.5 cN / dtex, 6 cN / dtex, 6.5 cN / dtex, 7 cN / dtex, etc.).

[0013] Preferably, the high-strength yarn comprises any one of ultra-high molecular weight polyethylene, nylon, polyester, carbon fiber, polyimide, and high-strength polyarylate, or a combination of at least two thereof.

[0014] Preferably, the melting point of the TPU is 120-160°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, etc.

[0015] Preferably, the foaming agent includes any one of dichloromethane, cyclopentane, nitrogen, and carbon dioxide, or a combination of at least two thereof.

[0016] Preferably, the raw material for preparing the skin layer, based on the weight amount of TPU as 100%, the amount of the foaming agent is 5%-15%, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc.

[0017] Preferably, the density of the lightweight and high-strength foamed TPU coated yarn is at least 0.2 g / cm2 lower than that of ordinary TPU coated yarn at the same volume. 3 , such as 0.2g / cm 3 , 0.3g / cm 3 , 0.4g / cm 3 , 0.5g / cm 3 wait.

[0018] Preferably, the ratio of the cross-sectional area of the cortex and the core yarn is (2.5-3.5):(6.5-7.5), wherein the cortex accounts for 25%-35%, for example, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, etc., and the core yarn accounts for 65%-75%, for example, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, etc.

[0019] In a second aspect, the present invention provides a method for preparing the lightweight, high-strength foamed TPU coated yarn as described in the first aspect, the preparation method comprising the following steps:

[0020] (1) melting TPU and then adding a foaming agent to obtain modified TPU;

[0021] (2) The modified TPU is coated on the surface of the high-strength yarn and foamed to obtain the lightweight high-strength foamed TPU coated yarn.

[0022] Preferably, the foaming in step (2) can be carried out by microwave heating and hot air curing to cause the foaming agent in the TPU to induce slight low-density foaming, thereby forming a special yarn with a skin-core structure with slightly foamed TPU as the skin layer and ultra-high molecular weight polyethylene as the core layer.

[0023] Preferably, the preparation method specifically comprises the following steps:

[0024] (A) placing TPU in a twin-screw extruder for melting, then adding a foaming agent, extruding, cooling, and pelletizing to obtain modified TPU slices;

[0025] (B) The modified TPU slices are added to a twin-screw extruder, heated and melted, and then extruded. The high-strength yarn is loaded on a reel and pulled to an extrusion die. The melted modified TPU passes through the extrusion die and is gradually coated on the surface of the high-strength yarn. The coated yarn is then passed through a hot air tunnel for foaming to obtain the lightweight, high-strength foamed TPU coated yarn.

[0026] Preferably, the TPU in step (A) is a TPU slice.

[0027] Preferably, the melting temperature in step (A) is 120-170°C, for example, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, etc.

[0028] Preferably, the cooling in step (A) is carried out in a cold water tank.

[0029] Preferably, the temperature of the cold water tank is 8-15°C, such as 8°C, 10°C, 12°C, 13°C, 15°C, etc.

[0030] Preferably, the step (B) further comprises drying the modified TPU chips before adding the modified TPU chips into the twin-screw extruder, so that the moisture content thereof is controlled to be below 0.2%.

[0031] Preferably, the drying temperature is 70-90°C, such as 70°C, 75°C, 80°C, 85°C, 90°C, etc., and the drying time is 2-4 hours, such as 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, etc.

[0032] Preferably, the parameters of the twin-screw extruder in step (B) are: an extrusion temperature of 100-115°C in the first zone (e.g., 100°C, 105°C, 110°C, 115°C, etc.), an extrusion temperature of 120-130°C in the second zone (e.g., 120°C, 125°C, 130°C, etc.), an extrusion temperature of 135-140°C in the third zone (e.g., 135°C, 138°C, 140°C, etc.), an extrusion temperature of 145-155°C in the fourth zone (e.g., 145°C, 150°C, 155°C, etc.), a motor speed of 15-25rpm (e.g., 15rpm, 18rpm, 20rpm, 22rpm, 23rpm, 25rpm, etc.), and a melt pressure of 0.2-0.4MPa (e.g., 0.2MPa, 0.25MPa, 0.3MPa, 0.35MPa, 0.4MPa, etc.).

[0033] Preferably, the hot air temperature of the hot air tunnel is 100-120°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C, etc.

[0034] Preferably, after the foaming through the hot air tunnel in step (B), the method further comprises the following steps: passing through a cooling unit and a stretching unit in sequence, and rewinding at the other end.

[0035] In a third aspect, the present invention provides a woven fabric, which is woven from the lightweight, high-strength foamed TPU coated yarn described in the first aspect, or the woven fabric is woven from the lightweight, high-strength foamed TPU coated yarn described in the first aspect and other yarns.

[0036] Preferably, the other yarns comprise polyester yarns.

[0037] Preferably, the braided fabric includes woven fabric and flyweave fabric. When the present invention uses flyweave for braiding, the main body is a knitted fabric, which is composed of the above-mentioned lightweight high-strength foamed TPU coated yarn of the skin-core structure or a composite braided fabric of the same with other yarns.

[0038] In a fourth aspect, the present invention provides a woven shoe upper, which includes the lightweight, high-strength foamed TPU coated yarn described in the first aspect, or the woven shoe upper is obtained by ironing the woven fabric described in the third aspect.

[0039] Preferably, the ironing temperature is 120-135°C, for example, 120°C, 125°C, 130°C, 135°C, etc., and the ironing time is 120-150s, for example, 120s, 125s, 130s, 135s, 140s, 145s, 150s, etc.

[0040] In a fifth aspect, the present invention provides a use of the braided shoe upper described in the fourth aspect in outdoor shoes, mountaineering shoes, hiking shoes, and road cycling shoes. The braided shoe upper provided by the present invention is expected to play a significant role in these fields, providing a new product for the domestic shoe upper market and significantly improving professional athletic performance.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The foamed TPU coated yarn provided by the present invention is lightweight by combining high-strength yarn with TPU foaming technology; the high-strength yarn is used as the core yarn, and the foamed TPU is used as the skin layer to cover the core yarn, which can keep the core yarn in its original shape during high temperature and not be destroyed; after foaming, the same wire diameter can achieve a lightweight and soft effect, which can solve the problem of decreased mechanical properties of TPU after foaming. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a flow chart for preparing the lightweight, high-strength foamed TPU coated yarn provided in Example 1.

[0044] Figure 2 This is a schematic structural diagram of the lightweight, high-strength foamed TPU coated yarn provided in Example 1;

[0045] Among them, 1-ultra-high molecular weight polyethylene core yarn, 2-foamed TPU skin layer.

[0046] Figure 3A This is the design organization diagram drawn in Application Example 1.

[0047] Figure 3B Schematic diagram of the structure of the woven fabric provided for Application Example 1.

[0048] Figure 4A This is the design layout drawn in Application Example 5.

[0049] Figure 4B Schematic diagram of the structure of the flywoven fabric provided for Application Example 5. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0051] Example 1

[0052] In this embodiment, a lightweight and high-strength foamed TPU coated yarn is provided, and the preparation flow chart is as follows: Figure 1 As shown, the preparation method comprises the following steps:

[0053] S1: Prepare the materials. Select the following raw materials: TPU slice material with a melting point of 150°C and a core yarn of ultra-high molecular weight polyethylene with a molecular weight of 2 million;

[0054] S2: Modification: Place the dried TPU slices in a twin-screw extruder for melting at a melting temperature of 155°C; add a foaming agent (cyclopentane) when the slices are melted into a fluid state for modification and extrusion;

[0055] Wherein, based on the weight of the TPU slice being 100%, the amount of the foaming agent is 8%;

[0056] S3: Cooling and pelletizing: placing the modified TPU into a cold water tank for water cooling and pelletizing to obtain modified TPU slices, wherein the temperature of the cold water tank is 10°C;

[0057] S4: Drying: Drying the modified TPU slices in hot air at 80°C for 4 hours to remove moisture from the slices and control the moisture content to 0.2%;

[0058] S5: Coating, the dried modified TPU slices are put into a twin-screw extruder, heated and melted, and then extruded. The ultra-high molecular weight polyethylene is pulled onto the extrusion die. The melted modified TPU passes through the extrusion die and is gradually coated on the surface of the ultra-high molecular weight polyethylene. The extrusion temperatures in each zone of the extruder are: 110°C, 120°C, 140°C, and 145°C, the motor speed is 20 rpm, and the melt pressure is 0.3 MPa;

[0059] S6: Foaming: passing the coated yarn through a hot air tunnel and hot air curing to perform slight foaming, wherein the hot air temperature is 110°C;

[0060] S7: Winding: The prepared modified TPU foam yarn is wound up by a winding device to obtain a lightweight and high-strength foamed TPU coated yarn whose core yarn is ultra-high molecular polyethylene.

[0061] The structural diagram of the lightweight and high-strength foamed TPU coated yarn provided in this embodiment is as follows: Figure 2 shown.

[0062] Example 2

[0063] In this embodiment, a lightweight, high-strength foamed TPU coated yarn is provided, and a preparation method thereof comprises the following steps:

[0064] S1: Prepare the materials. Select the following raw materials: TPU slice material, melting point 160℃, core yarn is high-strength polyarylate, brand VECTRAN TM ;

[0065] S2: Modification: Place the dried TPU slices in a twin-screw extruder for melting at a melting temperature of 165°C; add a foaming agent (nitrogen) when the slices are melted into a fluid state to modify the material and extrude;

[0066] Wherein, the amount of the foaming agent is 10% based on the weight of the TPU slice as 100%;

[0067] S3: Cooling and pelletizing: placing the modified TPU into a cold water tank for water cooling and pelletizing to obtain modified TPU slices, wherein the temperature of the cold water tank is 10°C;

[0068] S4: Drying: Drying the modified TPU slices in hot air at 80°C for 4 hours to remove moisture from the slices and control the moisture content to 0.2%;

[0069] S5: Coating, the dried modified TPU slices are put into a twin-screw extruder, heated and melted, and then extruded, and the high-strength polyarylate is pulled onto the extrusion die. The melted modified TPU passes through the extrusion die and is gradually coated on the surface of the high-strength polyarylate. The extrusion temperatures of various zones of the extruder are: 110°C, 120°C, 140°C, and 150°C, the motor speed is 20 rpm, and the melt pressure is 0.3 MPa;

[0070] S6: Foaming: passing the coated yarn through a hot air tunnel and hot air curing to perform slight foaming, wherein the hot air temperature is 110°C;

[0071] S7: Winding up the prepared modified TPU foam yarn through a winding device to obtain a lightweight and high-strength foamed TPU coated yarn whose core yarn is a high-strength polyarylate.

[0072] Example 3

[0073] In this embodiment, a lightweight, high-strength foamed TPU coated yarn is provided, and a preparation method thereof comprises the following steps:

[0074] S1: Prepare the materials. Select the following raw materials: TPU slice material with a melting point of 150°C and a core yarn of ultra-high molecular weight polyethylene with a molecular weight of 2 million;

[0075] S2: Modification: Place the dried TPU slices in a twin-screw extruder for melting at a melting temperature of 155°C; add a foaming agent (cyclopentane) when the slices are melted into a fluid state for material modification and extrusion;

[0076] Wherein, based on the weight of the TPU slice being 100%, the amount of the foaming agent is 15%;

[0077] S3: Cooling and pelletizing: placing the modified TPU into a cold water tank for water cooling and pelletizing to obtain modified TPU slices, wherein the temperature of the cold water tank is 10°C;

[0078] S4: Drying: Drying the modified TPU slices in hot air at 80°C for 4 hours to remove moisture from the slices and control the moisture content to 0.2%;

[0079] S5: Coating, the dried modified TPU slices are put into a twin-screw extruder, heated and melted, and then extruded. The ultra-high molecular weight polyethylene is pulled onto the extrusion die. The melted modified TPU passes through the extrusion die and is gradually coated on the surface of the ultra-high molecular weight polyethylene. The extrusion temperatures in each zone of the extruder are: 110°C, 120°C, 140°C, and 145°C, the motor speed is 20 rpm, and the melt pressure is 0.3 MPa;

[0080] S6: Foaming: passing the coated yarn through a hot air tunnel and hot air curing to perform slight foaming, wherein the hot air temperature is 110°C;

[0081] S7: Winding: The prepared modified TPU foam yarn is wound up by a winding device to obtain a lightweight and high-strength foamed TPU coated yarn whose core yarn is ultra-high molecular polyethylene.

[0082] Example 4

[0083] The only difference between this embodiment and embodiment 1 is that the blowing agent cyclopentane is replaced by the same weight of the blowing agent heat-expandable microspheres. 909DU 80.

[0084] Comparative Example 1

[0085] In this comparative example, a TPU ultra-high molecular weight polyethylene coated yarn is provided, which is different from Example 1 only in that the core yarn is ultra-high molecular weight polyethylene and is coated with unmodified TPU as the skin layer (i.e., no foaming agent is added to S2).

[0086] The density of the coated yarn provided in the embodiment and the comparative example was tested. The test method was as follows: 100m of coated yarn was weighed and its mass was recorded. Then, the yarn was placed in a container with a scale and a volume of 10cm. 2 A 2kg weight was placed in a water tank, and the resulting volume of water was recorded as V1. The weight was then attached to 100m of covered yarn, and the resulting volume of water was recorded as V2. The volume of the covered yarn was V2-V1, and its density was calculated using the formula ρ = m(100m) / V2-V1. The test results are shown in Table 1 below.

[0087] Table 1

[0088]

[0089]

[0090] It can be seen from Table 1 that the foamed TPU coated yarns provided in the embodiments of the present invention all have a relatively low density, and the addition of different contents of foaming agent affects the foaming degree of the lightweight and high-strength foamed TPU coated yarn. The higher the amount of foaming agent added, the higher the foaming degree.

[0091] The breaking strength of the covered yarns provided in the examples and comparative examples was tested using the test method in accordance with GB / T 19975-2005. The test results are shown in Table 2 below.

[0092] Table 2

[0093]

[0094] It can be seen from Table 2 that the foamed TPU coated yarns provided in the embodiments of the present invention all have high breaking strength, and the change of the added core yarn has an effect on the strength of the lightweight and high-strength foamed TPU coated yarn, but the change of the foaming agent content and type has no obvious effect on the strength.

[0095] Application Example 1

[0096] In this application example, a woven fabric is provided, and a preparation method thereof includes the following steps:

[0097] S1: Prepare yarns, using the lightweight, high-strength foamed TPU-coated yarn provided in Example 1 as weft yarns and P-DTY150D / 48F*2 biodegradable polyester doubled yarns as warp yarns;

[0098] S2: Warping, arranging the prepared high-strength polyester yarn onto the warp;

[0099] S3: Sizing, using low-temperature sizing and sizing process, sizing temperature of 43 ° C, single dipping and single pressing, sizing rate of 8%, sizing moisture regain below 3%;

[0100] S4: Threading the warp: according to the requirements of the process design, the warp yarn wound on the weaving beam is passed through the heddle eye and the reed teeth in a regular pattern, and then an open warp stop piece is inserted on the warp yarn;

[0101] S5: Read the sample and import the drawn design organization chart program (such as Figure 3A As shown), shuttle loom reading sample;

[0102] S6: Weaving pattern, weaving using weft and warp yarns according to the process;

[0103] S7: Activation and shaping: collect the woven fabrics, the activation temperature is 130℃, and the activation time is about 140s.

[0104] The structural diagram of the woven fabric provided in this application example is as follows Figure 3B shown.

[0105] Application Examples 2-4

[0106] The only difference from Application Example 1 is that the lightweight, high-strength foamed TPU covered yarn provided in Example 1 is replaced by the lightweight, high-strength foamed TPU covered yarn provided in Examples 2-4.

[0107] Comparative Application Example 1

[0108] The only difference between this comparative application example and application example 1 is that the lightweight high-strength foamed TPU coated yarn provided in Example 1 is replaced by the TPU ultra-high molecular weight polyethylene coated yarn provided in Comparative Example 1.

[0109] Corresponding to Use Cases 2-4 and Comparative Application Example 1, the same size woven fabrics were tested and their physical properties were tested according to the QP-LN-P006 Running Shoe Upper Stress Part Product Property Standard (LX-P-006);

[0110] The test results are shown in Table 3.

[0111] Table 3

[0112]

[0113] As can be seen from Table 3, the woven fabric prepared by the TPU coated yarn using the lightweight low-density foaming technology of the present invention has the same excellent bursting strength, tear strength and tensile strength as the woven fabric prepared by the ordinary ultra-high molecular weight polyethylene coated yarn, and the weight of the product is lighter, indicating that the TPU coated woven fabric using the lightweight low-density foaming technology of the present invention has the same excellent mechanical properties as the TPU ultra-high molecular weight polyethylene coated woven fabric.

[0114] Application Example 5

[0115] In this application example, a flywoven fabric is provided, and a preparation method thereof includes the following steps:

[0116] S1: The lightweight and high-strength foamed TPU coated yarn provided in Example 1 is used as the yarn;

[0117] S2: Read the sample and import the drawn design layout program (such as Figure 4A As shown), computer flat knitting machine reads the sample;

[0118] S3: threading the yarn into the yarn guide port on the flying loom according to the pattern, wherein the yarn is the lightweight and high-strength foamed TPU coated yarn provided in Example 1;

[0119] S4: knitting sample, the flying loom knits according to the knitting pattern, the front needle bed knits the loops on the front side, the knitting density is 250, and the pulling main roller parameter is 25;

[0120] S5: Activation and shaping: collect the woven fabrics, the activation temperature is 130℃, and the activation time is about 150s.

[0121] The structural diagram of the flywoven fabric provided in this application example is as follows Figure 4B shown.

[0122] Application Examples 6-8

[0123] The only difference from Application Example 5 is that the lightweight, high-strength foamed TPU covered yarn provided in Example 1 is replaced by the lightweight, high-strength foamed TPU covered yarn provided in Examples 2-4.

[0124] Comparative Application Example 2

[0125] The only difference between this comparative application example and application example 5 is that the lightweight high-strength foamed TPU coated yarn provided in Example 1 is replaced by the TPU ultra-high molecular weight polyethylene coated yarn provided in Comparative Example 2.

[0126] The flywoven fabrics of the same size as provided in Example 5-8 and Comparative Example 2 were tested, and their physical properties were tested according to the QP-LN-P006 Running Shoe Upper Stress Part Product Property Standard (LX-P-006);

[0127] The test results are shown in Table 4.

[0128] Table 4

[0129]

[0130] As can be seen from Table 4, the fly-woven fabric prepared by the TPU coated yarn using the lightweight low-density foaming technology of the present invention has the same excellent bursting strength, tear strength and tensile strength as the fly-woven fabric prepared by using the ordinary TPU ultra-high molecular weight polyethylene coated yarn, and the weight of the product is lighter, indicating that the fly-woven fabric made of the TPU coated yarn using the lightweight low-density foaming technology of the present invention has the same excellent mechanical properties as the fly-woven fabric made of the TPU ultra-high molecular weight polyethylene coated yarn.

[0131] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the lightweight, high-strength foamed TPU-coated yarn, its preparation method, and its application. However, the present invention is not limited to the above-mentioned embodiments, which does not mean that the present invention must rely on the above-mentioned embodiments for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for the raw materials used in the present invention, addition of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A lightweight, high-strength foamed TPU coated yarn, characterized in that: The lightweight and high-strength foamed TPU coated yarn includes a core yarn and a skin layer; The core yarn is a high-strength yarn; The skin layer is foamed TPU, and the raw materials for preparing the skin layer include TPU and a foaming agent.

2. The lightweight and high-strength foamed TPU coated yarn according to claim 1, characterized in that: The high-strength yarn is a yarn with a breaking strength in the range of 5-7 cN / dtex; Preferably, the high-strength yarn comprises any one or a combination of at least two of ultra-high molecular weight polyethylene, nylon, polyester, carbon fiber, polyimide, and high-strength polyarylate; Preferably, the melting point of the TPU is 120-160°C; Preferably, the foaming agent includes any one of dichloromethane, cyclopentane, nitrogen, and carbon dioxide, or a combination of at least two thereof; Preferably, the amount of the foaming agent used in the preparation of the skin layer is 5%-15% based on the weight of TPU as 100%; Preferably, the density of the lightweight and high-strength foamed TPU coated yarn is at least 0.2 g / cm2 lower than that of ordinary TPU coated yarn at the same volume. 3 .

3. The lightweight, high-strength foamed TPU coated yarn according to claim 1 or 2, characterized in that: The cross-sectional area ratio of the cortex and the core yarn is (2.5-3.5):(6.5-7.5), wherein the cortex accounts for 25%-35% and the core yarn accounts for 65%-75%.

4. A method for preparing a lightweight, high-strength foamed TPU coated yarn according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: (1) melting TPU and then adding a foaming agent to obtain modified TPU; (2) The modified TPU is coated on the surface of the high-strength yarn and foamed to obtain the lightweight high-strength foamed TPU coated yarn.

5. The preparation method according to claim 4, characterized in that The preparation method specifically comprises the following steps: (A) placing TPU in a twin-screw extruder for melting, then adding a foaming agent, extruding, cooling, and pelletizing to obtain modified TPU slices; (B) adding the modified TPU slices into a twin-screw extruder, heating and melting them, and then extruding them. The high-strength yarn is pulled onto the extrusion port die. The melted modified TPU passes through the extrusion port and is gradually coated on the surface of the high-strength yarn. The coated yarn is then passed through a hot air tunnel for foaming to obtain the lightweight high-strength foamed TPU coated yarn.

6. The preparation method according to claim 5, characterized in that The TPU in step (A) is a TPU slice; Preferably, the melting temperature in step (A) is 120-170°C; Preferably, the cooling in step (A) is carried out in a cold water tank; Preferably, the temperature of the cold water tank is 8-15°C.

7. The preparation method according to claim 5 or 6, characterized in that: Before adding the modified TPU slices into the twin-screw extruder in step (B), the modified TPU slices may be dried; Preferably, the drying temperature is 70-90°C and the drying time is 2-4 hours; Preferably, the parameters of the twin-screw extruder in step (B) are: extrusion temperature in the first zone is 100-115°C, extrusion temperature in the second zone is 120-130°C, extrusion temperature in the third zone is 135-140°C, extrusion temperature in the fourth zone is 145-155°C, motor speed is 15-25 rpm, and melt pressure is 0.2-0.4 MPa; Preferably, the hot air temperature of the hot air tunnel is 100-120°C; Preferably, after the foaming through the hot air tunnel in step (B), the method further comprises the following steps: passing through a cooling unit and a stretching unit in sequence, and rewinding at the other end.

8. A woven fabric, characterized in that: The woven fabric is woven from the lightweight, high-strength foamed TPU coated yarn according to any one of claims 1 to 3, or the woven fabric is woven from the lightweight, high-strength foamed TPU coated yarn according to any one of claims 1 to 3 and other yarns; Preferably, the other yarns include polyester yarns; Preferably, the woven fabric includes woven fabric and flywoven fabric.

9. A woven shoe upper, characterized in that: The woven shoe upper comprises the lightweight, high-strength foamed TPU coated yarn according to any one of claims 1 to 3, or the woven shoe upper is obtained by ironing the woven fabric according to claim 8; Preferably, the ironing temperature is 120-135° C., and the ironing time is 120-150 seconds.

10. Use of the braided shoe upper according to claim 9 in outdoor shoes, mountaineering shoes, hiking shoes, and road cycling shoes.

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