High resilience thick denier single-hole spandex and its preparation method

Abstract

The present invention provides a high-elasticity thick-denier single-hole spandex and a preparation method thereof. The high-elasticity thick-denier single-hole spandex is formed by a polyurethane spinning solution ejected through a single-hole spinning orifice and then successively passing through a hot air duct and a silicone oil medium to complete the rapid diffusion of medium- and low-boiling-point solvents and the rapid solidification of a polyurethane prepolymer. The preparation method utilizes the compatibility of silicone oil with medium- and low-boiling-point solvents and the relatively high heat capacity of silicone oil, enabling the medium- and low-boiling-point solvents to volatilize fully and the spandex fibers to be formed rapidly, thereby preparing thick-denier spandex fibers with high-elasticity characteristics. These spandex fibers can be directly used in the subsequent processing of textile fabrics, and the efficient forming process can effectively shorten the spinning process to ensure the full volatilization of solvents, showing great prospects for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of spandex material preparation, and particularly relates to a high-elasticity thick-denier single-hole spandex and a preparation method thereof. Background Art

[0002] Polyurethane fibers have excellent elasticity and resilience and have been widely used in fields such as textile and clothing, biomedicine, and energy sensing. Their preparation processes mainly include dry spinning, wet spinning, melt spinning, and chemical reaction spinning. Among them, dry solution spinning has been explored for many years, and the technology has become mature. It can be continuously produced, with high efficiency and good product performance, so it has been widely used. However, due to reasons such as complex production equipment and large investment, the expansion of its production scale is limited. Moreover, in the process of using hot air in the tunnel to volatilize the solvent in dry solution spinning, problems such as incomplete solvent volatilization and difficult recovery of hot air are likely to occur, which have become obstacles to the further development of dry solution spinning.

[0003] The invention patent with the publication number CN108796635A discloses a spandex spinning tunnel air duct device. The device includes a control motor box with a T-shaped blower installed thereon, automatic constant pressure devices and air supply valves provided on both sides of the bottom outlet of the T-shaped blower, an inverted U-shaped air supply duct fixedly connected below the T-shaped blower, a spinning tunnel with a wind blade opening embedded in the bottom of the inverted U-shaped air supply duct, a wind speed stabilizer provided on the side wall of the spinning tunnel, an exhaust duct with an exhaust valve arranged in a row at the bottom of the spinning tunnel in sequence, and a return air collecting box, aiming to overcome the deficiencies such as incomplete cooling and shaping of the fiber bundle in the tunnel in the prior art. By improving the direction of the air duct in the ventilation duct of the spinning tunnel, the cooling time and effect are ensured, thereby improving the spandex spinning quality. However, the above device still has the technical defect of incomplete solvent volatilization, is not suitable for the development of thick-denier fibers, and there are also defects of high equipment investment and operation costs when improving the device.

[0004] The invention patent with the publication number CN103668490A discloses a spandex dry spinning medium circulation method and system. Taking the mixture of DMAC and the medium discharged from the spinning tunnel as the treatment object, the DMAC in the mixture is recovered through a heat exchanger (group) and a membrane separation process system. The separated DMAC is sent to the DMAC storage tank, and the remaining medium is returned to the spinning tunnel after being heated to a certain temperature to be used as hot air for drying the solvent in the spinning dope. However, it has the technical deficiencies that it is not suitable for the development of thick-denier high-elasticity spandex fibers. In a continuous high-temperature air atmosphere, a highly dense layer is easily formed on the fiber surface quickly, resulting in slow formation of polyurethane inside the thick-denier fibers, leading to deviation of the fiber shape from a circle and formation of skin-core structure defects.

[0005] In view of this, it is necessary to design an improved high-elasticity thick-denier single-hole spandex and its preparation method to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-elasticity thick-denier single-hole spandex and its preparation method. By utilizing the characteristics of the medium-low boiling point of the polyurethane solvent and the high heat capacity of the silicone oil, through the affinity and synergistic effect between the silicone oil and the polyurethane solvent, and based on the compatibility and rapid diffusion of the medium-low boiling point solvent in the silicone oil, a high-elasticity transparent thick-denier single-hole spandex is prepared.

[0007] To achieve the above-mentioned invention purpose, the present invention provides a high-elasticity thick-denier single-hole spandex, which is formed by extruding a polyurethane spinning solution through a single-hole spinning orifice, and then successively passing through a hot air duct and a silicone oil medium to complete the rapid and complete diffusion of the medium-low boiling point solvent and the rapid solidification of the polyurethane prepolymer.

[0008] Calculated by mass percentage, the polyurethane spinning solution is composed of 15-45% of polyurethane prepolymer and 55-85% of medium-low boiling point solvent.

[0009] The single filament linear density of the high-elasticity thick-denier single-hole spandex is 100-560 D, the breaking strain reaches 500-1000%; the elastic recovery rate after 300% elongation reaches 95-99%; the boiling water shrinkage rate reaches 1-8%.

[0010] As a further improvement of the present invention, the polyurethane prepolymer is one of thermoplastic polyether-based polyurethane, thermoplastic polyester-based polyurethane, and thermoplastic polyether-polyester-based polyurethane.

[0011] As a further improvement of the present invention, the medium-low boiling point solvent is one or a mixture of two of tetrahydrofuran and dioxane.

[0012] As a further improvement of the present invention, the silicone oil medium is one or a combination of two or more of dimethyl silicone oil, diethyl silicone oil, benzyl silicone oil, hydroxy silicone oil, and methyl hydrogen-containing silicone oil.

[0013] As a further improvement of the present invention, the heating temperature of the silicone oil medium is 70-120 °C.

[0014] As a further improvement of the present invention, the temperature range of the hot air duct is 40-100 °C, and the distance is 10-20 mm.

[0015] To achieve the above-mentioned invention purpose, the present invention also provides a preparation method of the above-mentioned high-elasticity thick-denier single-hole spandex, including the following steps:

[0016] S1. Preparation of polyurethane spinning solution: Add polyurethane prepolymer to medium and low boiling point solvents in a predetermined ratio, mechanically stir and mix evenly, and then perform degassing treatment to obtain a polyurethane spinning solution;

[0017] S2. Preparation method of high resilience thick denier single-hole spandex: Place the polyurethane spinning solution in a spinning device, spray it out at a predetermined rate through a single-hole spinning orifice of a predetermined size. After the preformed polyurethane filament passes through a hot air duct of a predetermined distance, it enters a silicone oil medium at a predetermined heating temperature. Under the action of high-temperature silicone oil, the medium and low boiling point solvents in the preformed polyurethane filament rapidly diffuse, and the concentration of the polyurethane prepolymer continuously increases until the filament rapidly solidifies and forms, obtaining the first high resilience thick denier single-hole spandex. Or, subject the solidified filament to a stretching treatment at a predetermined temperature and a predetermined draw ratio to obtain the second high resilience thick denier single-hole spandex.

[0018] As a further improvement of the present invention, in step S2, the distance between the preformed polyurethane filament entering the silicone oil medium and the surface of the silicone oil medium is 20 - 50 mm.

[0019] As a further improvement of the present invention, in step S2, the temperature of the stretching treatment is 40 - 90 °C.

[0020] As a further improvement of the present invention, in step S2, the draw ratio is 1 - 2.

[0021] The beneficial effects of the present invention are:

[0022] 1. The preparation method of high resilience thick denier single-hole spandex provided by the present invention introduces a liquid silicone oil-induced solvent volatilization forming process, ensuring complete contact between the liquid medium silicone oil and the polyurethane filament. The medium and low boiling point solvents in the polyurethane spinning solution can completely enter the high-temperature silicone oil, and the continuous and rapid volatilization of the medium and low boiling point solvents is maintained, solving the technical problems of uneven and incomplete solvent volatilization rates inside and outside in the dry spinning method; Utilizing the medium and low boiling points of the polyurethane solvent and the high heat capacity characteristics of the silicone oil, during the production process, the temperature of the silicone oil is set lower than the softening point of the polyurethane polymer but higher than the boiling point of the medium and low boiling point good solvent. Utilizing the synergistic effect of the affinity between the silicone oil and the polyurethane solvent, each serves as a condition for solvent volatilization. Utilizing the compatibility and rapid diffusion characteristics of the medium and low boiling point solvents in the silicone oil, the medium and low boiling point solvents volatilize rapidly and completely, and high resilience transparent thick denier single-hole spandex is prepared.

[0023] 2. The preparation method of the high-elasticity thick-denier single-hole spandex provided by the present invention, on the one hand, utilizes the medium and low boiling point characteristics of the good solvent of polyurethane adopted, and constructs a high-temperature medium silicone oil system in the process of forming polyurethane filaments, which accelerates the rapid volatilization of the medium and low boiling point solvents in the preformed polyurethane fiber filaments, is beneficial to shortening the spinning forming time, and is also beneficial to the formation of a uniform and dense structure of polyurethane fibers. On the other hand, when the preformed polyurethane fiber filaments enter the heated silicone oil, by utilizing the affinity between the good solvent of polyurethane adopted and the silicone oil, the large amount of silicone oil outside the fiber during the solidification process has a greater acting force on the fiber, promoting the further rapid diffusion of the medium and low boiling point solvents in the fiber into the silicone oil, and accelerating the forming speed of polyurethane fibers. Since the forming process is fast and thorough, there will be no skin-core structure caused by the separation of rich and poor phases, and no wrinkle structure caused by different shrinkage degrees due to the difference in forming curing, and the obtained fiber is dense inside and has excellent performance. On the third hand, the plasticizing effect of the high-temperature medium silicone oil during the forming process is beneficial to the orientation drawing of the fiber.

[0024] 3. The preparation method of the high-elasticity thick-denier single-hole spandex provided by the present invention, the filaments prepared by the high-temperature oil bath spinning method have a uniform network structure, and can also be further drawn, transforming the randomly oriented macromolecular network into a continuous oriented structure oriented along the fiber axis, which can effectively improve the strength, modulus and elastic recovery rate of spandex.

[0025] 4. The preparation method of the high-elasticity thick-denier single-hole spandex provided by the present invention uses liquid high-temperature silicone oil as the medium for the formation of polyurethane fibers. The liquid silicone oil can quickly spread on the surface of the filaments, and the high-temperature silicone oil enables the medium and low boiling point solvents to be completely volatilized, reducing the difficulty of the spinning process and enabling the preparation of high-quality densified spandex fibers. Its preparation process is simple. By using the oil bath spinning method, single-hole thick-denier spandex fibers without skin-core structure, with a densified circular cross-section and high-elasticity performance can be quickly obtained, having good economic benefits.

[0026] 5. The high-elasticity thick-denier single-hole spandex provided by the present invention has high-elasticity characteristics. This spandex fiber can be directly used in the processing of subsequent textile fabrics, and the efficient forming process can effectively shorten the spinning process to ensure the full volatilization of the solvent, having great industrial production prospects. Description of the Drawings

[0027] Figure 1 is the electron micrograph of the high-elasticity thick-denier single-hole spandex provided by the present invention ( Figure 1 in which a is Example 1, and the scale bar is 50 μm; Figure 1 in which b is Example 26, and the scale bar is 50 μm; Figure 1 in which c is Example 27, and the scale bar is 30 μm; Figure 1 in which d is Example 28, and the scale bar is 30 μm; Figure 1In e, it is Example 29, and the scale bar is 30 μm; Figure 1 In f, it is Example 30, and the scale bar is 50 μm). Detailed implementation manners

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Here, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, and other details less related to the present invention are omitted.

[0030] In addition, it should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0031] The present invention provides a method for preparing a high-elasticity thick-denier single-hole spandex, comprising the following steps:

[0032] S1, preparation of a polyurethane spinning solution: adding a polyurethane prepolymer to a medium- and low-boiling-point solvent in a predetermined ratio, mechanically stirring and mixing evenly, and then performing degassing treatment to obtain a polyurethane spinning solution;

[0033] S2, method for preparing a high-elasticity thick-denier single-hole spandex: placing the polyurethane spinning solution in a spinning device, spraying it out at a predetermined rate through a single-hole spinning orifice of a predetermined size, after the preformed polyurethane filament passes through a hot air duct of a predetermined distance, entering a silicone oil medium at a predetermined heating temperature, under the action of high-temperature silicone oil, the medium- and low-boiling-point solvents in the preformed polyurethane filament rapidly diffuse, and the concentration of the polyurethane prepolymer continuously increases until the filament rapidly solidifies and forms a first high-elasticity thick-denier single-hole spandex;

[0034] Or, subjecting the solidified filament to a drawing treatment at a predetermined temperature and a predetermined draw ratio to obtain a second high-elasticity thick-denier single-hole spandex, and finally winding it into a roll.

[0035] Preferably, in step S2, the distance between the preformed polyurethane filament entering the silicone oil medium and the surface of the silicone oil medium is 20-50 mm.

[0036] Preferably, in step S2, the temperature of the drawing treatment is 40-90 °C.

[0037] Preferably, in step S2, the draw ratio is 1-2.

[0038] The present invention will be further described below with specific embodiments.

[0039] Example 1

[0040] In Example 1 of the present invention, a preparation method of a high-elasticity thick-denier single-hole spandex was prepared, including the following steps:

[0041] S1. Weigh 25 g of PTMG-type polyether polyurethane (shore A 85) prepolymer and 75 g of tetrahydrofuran solvent and uniformly prepare a mixed solution, stir evenly under the condition that the room temperature is 20-30 °C, and perform vacuum degassing treatment on the polyurethane spinning solution under the condition that the temperature is 20-30 °C to obtain a polyurethane spinning solution with a solid content of 25%.

[0042] S2. Place the polyurethane spinning solution in a spinning device, and spray it out from a single-hole spinning orifice with an inner diameter of 0.9 mm at a spinning speed of 3 mm / min. After passing through a hot air spinning channel with a length of 10 mm and a temperature of 60 °C, it enters a dimethyl silicone oil medium at 105 °C. Without stretching, a single-hole spandex is prepared, and the spinning is wound up.

[0043] After performance testing, the single-filament linear density of the high-elasticity thick-denier single-hole spandex prepared in Example 1 is 150 D, and the breaking strain reaches 739%; the elastic recovery rate after 300% elongation reaches 99%; the boiling water shrinkage rate reaches 3%, and it has good elastic recovery performance.

[0044] Comparative Example 1

[0045] The difference from Example 1 is that in step S2, ordinary water bath (the medium is water) is used for coagulation treatment to prepare spandex.

[0046] Comparative Example 2

[0047] The difference from Example 1 is that in step S2, normal-temperature silicone oil (lower than the temperature of medium and low boiling point solvents) is used for coagulation treatment to prepare spandex.

[0048] After performance testing, the single-filament linear density of the single-hole spandex prepared in Comparative Example 1 is 145 D, and the breaking strain reaches 300%; the elastic recovery rate after 300% elongation reaches 85%; the boiling water shrinkage rate reaches 12 %, and the fiber cross-section is an oval porous structure with an obvious skin-core structure.

[0049] The single-filament linear density of the single-hole spandex prepared in Comparative Example 2 is 146 D, and the breaking strain reaches 800%; the elastic recovery rate after 300% elongation reaches 89%; the boiling water shrinkage rate reaches 15%, and the fiber cross-section is a flat belt shape.

[0050] The above shows that, compared with Comparative Examples 1-2, the method provided by the present invention, which uses high-temperature silicone oil medium as the coagulation bath to perform rapid forming treatment on the preformed polyurethane filament, is beneficial to the formation of dense and highly transparent circular cross-section fibers. At the same time, the fibers have good elastic recovery rate and low boiling water shrinkage rate, stable morphological dimensions, and are beneficial to textile production and processing applications.

[0051] Examples 2-7

[0052] Different from Example 1: During the spinning process, the solid content of the spinning solution was set differently, and the others were the same as in Example 1, which will not be elaborated here. The solid content settings and the performance increments compared with Example 1 are shown in Table 1.

[0053] Table 1 shows the spinning parameter settings and performance increment parameters in Examples 2-7

[0054]

[0055] As can be seen from Table 1, when the solid content of the polyurethane spinning solution (the proportion of polyurethane prepolymer) increases, the breaking stress of the prepared spandex increases significantly. Among them, when the solid content is 45%, the increment can reach 26%. However, when the solid content is relatively high, the strain and elastic recovery rate of the fiber decrease to a certain extent. When the solid content is relatively low, the boiling water shrinkage rate of the fiber increases significantly. The above shows that a certain concentration of solid content is beneficial to improving the stress, strain, elastic recovery rate and boiling water shrinkage rate of spandex fibers.

[0056] Examples 8-9

[0057] Different from Example 1: During the spinning process, the medium and low boiling point solvents were set differently, and the others were the same as in Example 1, which will not be elaborated here. The types of low boiling point solvents set and the performance increments compared with Example 1 are shown in Table 2.

[0058] Table 2 shows the spinning parameter settings and performance increment parameters in Examples 8-9

[0059]

[0060] As can be seen from Table 2, when the types of medium and low boiling point solvents in the spinning solution change, the breaking stress of the prepared spandex increases slightly, the breaking strain decreases, its elastic recovery rate increases, and the boiling water shrinkage rate hardly changes.

[0061] Examples 10-13

[0062] Different from Example 1: During the spinning process, the types of silicone oil were set differently, and the others were the same as in Example 1, which will not be elaborated here. The types of silicone oil set and the performance increments compared with Example 1 are shown in Table 3.

[0063] Table 3 shows the spinning parameter settings and performance increment parameters in Examples 10 - 13.

[0064]

[0065] As can be seen from Table 3, during the spinning process, the change in the type of silicone oil has little effect on the properties of spandex.

[0066] Examples 14 - 18

[0067] Different from Example 1: During the spinning process, the heating temperature of the silicone oil is set differently, and the rest are the same as in Example 1, which will not be elaborated here. The silicone oil heating temperature settings and the performance increments compared to Example 1 are shown in Table 4.

[0068] Table 4 shows the spinning parameter settings and performance increment parameters in Examples 14 - 17.

[0069]

[0070] As can be seen from Table 4, when the temperature of the silicone oil increases during the spinning process, the breaking stress of the spandex prepared increases, the elastic recovery rate decreases, and the boiling water shrinkage rate slightly increases.

[0071] Example 18

[0072] Example 18 of the present invention provides a method for preparing a high - resilience thick - denier single - hole spandex, which includes the following steps:

[0073] S1. Weigh 25 g of PTMG - type polyether - type polyurethane (shore A 85) prepolymer and 75 g of tetrahydrofuran solvent, and uniformly mix them to form a mixed solution. Stir evenly under the condition that the room temperature is 20 - 30 °C, and perform vacuum degassing treatment on the polyurethane spinning solution at a temperature of 20 - 30 °C to obtain a polyurethane spinning solution with a solid content of 25%.

[0074] S2. Place the polyurethane spinning solution in a spinning device, spray it out from a single - hole spinning orifice with an inner diameter of 0.9 mm, pass through a hot - air spinning channel with a length of 10 mm and a temperature of 60 °C, and then enter a dimethyl silicone oil medium at 100 °C, so that the medium - and low - boiling - point solvents in the filament rapidly diffuse and are carried away by the silicone oil. The concentration of the polyurethane prepolymer in the filament continuously increases until it solidifies. Then, pass through a drafting roller at a drafting temperature of 40 °C, and after being subjected to a drafting treatment with a drafting ratio of 1.2, a single - hole spandex is obtained, and finally wound into a roll.

[0075] Examples 19 - 22

[0076] Different from Example 18: During the spinning process, the drafting ratio is set differently, and the rest are the same as in Example 18, which will not be elaborated here. The drafting ratio settings and the performance increments compared to Example 1 are shown in Table 5.

[0077] Table 5 shows the spinning parameter settings and performance increment parameters in Examples 18 - 23.

[0078]

[0079] As can be seen from Table 5, when the spinning draft increases during the spinning process, the breaking stress of the spandex prepared increases significantly. Conversely, the breaking strain of the fiber decreases accordingly, and there is no obvious effect on the elastic recovery rate and boiling water shrinkage rate of the fiber.

[0080] Examples 23 - 27

[0081] Different from Example 18, during the spinning process, the draft temperature is set differently, and the others are the same as in Example 18, which will not be elaborated here. The draft temperature settings and the performance increments compared with Example 1 are shown in Table 6.

[0082] Table 6 shows the spinning parameter settings and performance increment parameters in Examples 23 - 27.

[0083]

[0084] As can be seen from Table 6, when the draft temperature increases during the spinning process, the breaking stress of the spandex prepared is significant. Conversely, the breaking strain of the fiber increases accordingly, and there is no obvious change in its elastic recovery rate and boiling water shrinkage rate.

[0085] Please refer to Figure 1 As shown, the cross-section of the spandex fiber prepared by the method provided by the present invention is circular and has no pores, and the inside of the fiber is dense, indicating that the fiber appearance morphology prepared by the method provided by the present invention is good.

[0086] It should be noted that those skilled in the art should understand that the polyurethane prepolymer in the embodiments of the present invention can also be one of other thermoplastic polyether-based polyurethanes, thermoplastic polyester-based polyurethanes, and thermoplastic polyether-polyester-based polyurethanes. In the embodiments of the present invention, the inner diameter of the single-hole spinning hole can also be adaptively adjusted according to actual application requirements, and high-elasticity thick-denier single-hole spandex can be prepared.

[0087] In summary, the present invention provides a high-elasticity thick-denier single-hole spandex and a preparation method thereof. By using the solution spinning method, a high-concentration spinning solution is injected into a heated silicone oil medium through a single-channel spinning nozzle. The heat effect of the silicone oil and its interaction with the medium and low-boiling-point solvents in the spinning solution cause the medium and low-boiling-point solvents to rapidly diffuse, thereby preparing a thick-denier spandex single filament with high-elasticity performance. The preparation method provided by the present invention utilizes the compatibility of the silicone oil with the medium and low-boiling-point solvents and the relatively high heat capacity of the silicone oil, enabling the medium and low-boiling-point solvents to fully volatilize and the spandex fibers to rapidly form. By fully utilizing the relationship between the medium and low-boiling points of the spinning solvent and the temperature of the heated silicone oil, the compatibility between the spinning solvent and the silicone oil, and the distribution of the hard and soft segments of the polyurethane, parameters such as the type and temperature of the silicone oil, the solid content of the spinning solution, and the draw ratio are regulated during the spinning process to prepare spandex fibers with high-elasticity characteristics. These spandex fibers can be directly used in the subsequent processing of textile fabrics, and the efficient forming process can effectively shorten the spinning process and ensure the full volatilization of the solvents, showing great prospects for industrial production.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high resilience thick denier single-hole spandex, characterized in that: The high-elasticity thick-denier single-hole spandex is formed by extruding a polyurethane spinning solution through a single-hole spinning orifice, sequentially passing through a hot air duct and a high-temperature silicone oil medium, and completing the processes of rapid and complete diffusion of medium- and low-boiling-point solvents and rapid solidification and molding of polyurethane prepolymers to form spandex fibers; Calculated by mass percentage, the polyurethane spinning solution is composed of 15-45% of polyurethane prepolymer and 55-85% of medium- and low-boiling-point solvents; Among them, the low-boiling-point solvent is one or a mixture of tetrahydrofuran and dioxane, and the silicone oil medium is one or a combination of dimethyl silicone oil, diethyl silicone oil, benzyl silicone oil, hydroxy silicone oil, and methyl hydrogen-containing silicone oil; The single-filament linear density of the high-elasticity thick-denier single-hole spandex is 100-560 D, the breaking strain reaches 500-1000%; the elastic recovery rate after 300% elongation reaches 95-99%; the boiling water shrinkage rate reaches 1-8%.

2. The high resilience thick denier single-hole spandex according to claim 1, characterized in that: The polyurethane prepolymer is one of thermoplastic polyether-based polyurethane, thermoplastic polyester-based polyurethane, and thermoplastic polyether-polyester-based polyurethane.

3. The high resilience thick-denier single-hole spandex according to claim 1, characterized in that: The heating temperature of the silicone oil medium is 70-120 °C.

4. The high-elasticity thick-denier single-hole spandex according to claim 1, characterized in that: The temperature range of the hot air duct is 40-100 °C, and the distance is 10-20 mm.

5. A method for preparing the high resilience thick denier single-hole spandex according to any one of claims 1 to 4, characterized in that: It includes the following steps: S1, Preparation of polyurethane spinning solution: Add the polyurethane prepolymer to the medium- and low-boiling-point solvents according to a predetermined ratio, mechanically stir and mix evenly, and then perform degassing treatment to obtain the polyurethane spinning solution; S2, Preparation method of high-elasticity thick-denier single-hole spandex: Place the polyurethane spinning solution in a spinning device, extrude it through a single-hole spinning orifice of a predetermined size at a predetermined rate, and after the preformed polyurethane filament passes through a hot air duct of a predetermined distance, enter the silicone oil medium at a predetermined heating temperature. Under the action of high-temperature silicone oil, the medium- and low-boiling-point solvents in the preformed polyurethane filament rapidly and fully diffuse, and the concentration of the polyurethane prepolymer continuously increases until the filament rapidly solidifies and forms, obtaining the first high-elasticity thick-denier single-hole spandex; Or, the solidified and formed filament is further subjected to stretching treatment at a predetermined temperature and a predetermined draw ratio to obtain the second high-elasticity thick-denier single-hole spandex.

6. The preparation method of the high resilience thick denier single-hole spandex according to claim 5, characterized in that: In step S2, the distance between the preformed polyurethane filament entering the silicone oil medium and the surface of the silicone oil medium is 20-50 mm.

7. The preparation method of the high resilience thick denier single-hole spandex according to claim 5, characterized in that: In step S2, the temperature of the stretching treatment is 40-90 °C.

8. The preparation method of the high resilience thick denier single-hole spandex according to claim 5, characterized in that: In step S2, the draw ratio is 1-2.

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