Cooling PVA filament melt spinning preparation method and cooling fabric

Abstract

The application discloses a melt spinning preparation method of cool PVA filaments and a cool fabric, and comprises water-containing PVA filament preparation and PDMS coating sizing; the preparation process of the water-containing PVA filaments comprises melt extrusion, primary drawing and secondary drawing; the preparation process of the modified PVA gel comprises the following steps: PVA particles with an alcoholysis degree of 99% are placed in an oven for drying; a water-polyol-dimethyl sulfoxide ternary compound plasticizing system is proportionally constructed, the dried PVA particles and the ternary compound plasticizing system are mixed under stirring, and after swelling, a heat stabilizer is added; dissolution, cooling forming and granulation are carried out; and a PDMS hydrophobic film is formed on the surface through the sizing process. The melt spinning method is more environmentally friendly, water is used as a heat storage system, long-acting cool feeling effect can be achieved through continuous heat absorption of water, and the dependence of traditional cool fibers on chemical additives is fundamentally solved.

Description

Technical Field

[0001] This invention relates to a melt spinning method for preparing cooling PVA filaments and cooling fabrics, belonging to the technical field of cooling PVA filaments. Background Technology

[0002] With the increasing frequency of extreme heatwaves globally and the upgrading of consumer demands, consumers have placed higher requirements on the coolness, comfort, environmental friendliness, and functionality of summer textiles. Cooling functional fibers have become a research hotspot and a key industrial direction in the textile materials field. Currently, most commercially available cooling fibers use petroleum-based synthetic fibers such as polyester and nylon as the matrix, primarily achieving the cooling effect through inorganic cooling powder blending modification, irregular cross-sectional structure design, or fabric finishing techniques. While these methods can improve the cooling sensation to some extent, unavoidable industry pain points remain: (1) Petroleum-based matrices are non-biodegradable, and both the production and disposal processes have a high environmental burden, which is contrary to the green and sustainable development trend of the textile industry; (2) Inorganic powder blending modification is prone to problems such as powder agglomeration and poor compatibility with the matrix. After long-term use and washing, powder is prone to fall off, resulting in insufficient durability of the cooling function. (3) The finishing technology has defects such as easy shedding of auxiliaries, deterioration of fabric hand feel, and reduced breathability, making it difficult to balance the cooling effect and wearing comfort.

[0003] PVA, as the only non-petroleum-based water-soluble biodegradable polymer material that can be mass-produced industrially, has a molecular chain rich in highly reactive hydroxyl groups, exhibiting excellent hydrophilicity, biocompatibility, and fiber-forming properties, making it an ideal matrix for preparing green, cooling fibers. Furthermore, it's worth noting that water has a high specific heat capacity of 4.2 × 10⁻⁶. 3 J / (kg・℃) is a widely available, green and pollution-free natural cooling medium. Based on the strong hydrophilicity of PVA fiber, a water-based heat storage system is constructed. It can achieve a long-lasting cooling effect through the continuous heat absorption of water, fundamentally solving the problem of the strong dependence of traditional cooling fibers on chemical additives. It has significant environmental advantages and performance potential.

[0004] Because PVA (polyvinyl alcohol) has a chemical structure with strong hydrogen bonds in multiple hydroxyl groups, its melting point and decomposition temperature are very close, resulting in a very small processing window. Therefore, PVA spinning generally cannot be carried out using melt spinning methods. To date, PVA spinning has mostly employed wet spinning, gel spinning, or dry spinning. These spinning methods are solution-based, complex, require large investments, and cause serious environmental pollution. PVA's molecular chain contains a large number of hydroxyl groups, forming numerous hydrogen bonds between molecules and intermolecular forces, resulting in high crystallinity. Since PVA does not have a specific melting point, its initial thermal decomposition temperature is 200-220℃, making melt spinning generally impossible. Melt spinning, compared to methods like wet spinning, is more environmentally friendly. The problem to be solved is how to prepare a cooling PVA filament using melt spinning and then fabricate a cooling PVA fabric from it. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a melt spinning method for preparing cooling PVA filaments and a cooling fabric.

[0006] To solve the above-mentioned technical problems, the objective of this invention is achieved as follows: The present invention relates to a melt spinning method for preparing cool-feeling PVA filaments, comprising the preparation of water-containing PVA filaments and PDMS coating and sizing; The preparation process of the water-containing PVA filament includes melt extrusion, primary drawing, and secondary drawing; The melt extrusion process involves heating the modified PVA gel to a melt using a screw extruder and extruding it through a spinneret. The preparation process of the modified PVA gel includes the following steps: S1.1 Pre-drying: Place PVA particles with a degree of alcoholysis of 99% in an oven for drying; S1.2 Pre-swelling: Construct a water-polyol-dimethyl sulfoxide ternary compound plasticizing system according to the proportion. Weigh the dried PVA particles and mix them with the ternary compound plasticizing system under stirring conditions. Swell for a set time in a closed environment at a set temperature. After swelling, add a heat stabilizer. S1.3 Dissolution: Transfer the swollen material to a constant temperature container equipped with a stirring device, set the dissolution temperature, and continuously stir to form PVA fluid; S1.4 Cooling and molding: Cooling the dissolved PVA fluid into a solid gel; S1.5, Pelletizing: The solid gel formed in the previous step is granulated to form gel particles; The PDMS coating and sizing process includes the following steps: S2.1 Preparation of PDMS coating solution: The PDMS coating solution is formed by mixing and stirring PDMS prepolymer and curing agent; S2.2 Sizing: PDMS coating solution is applied to the surface of water-containing PVA filaments; S2.3 Curing: The aqueous PVA filaments coated with PDMS coating liquid are cured at the curing temperature for a certain time to obtain cool-feeling PVA filaments.

[0007] Furthermore, in step S1.1, the PVA particles are dried at 80°C for 2 hours.

[0008] Furthermore, in step S1.2, the ratio of PVA:water:polyol:dimethyl sulfoxide by weight is 100:240:60:25.

[0009] Furthermore, in step S1.2, the swelling is performed in a closed environment at 60°C for 1-2 hours.

[0010] Furthermore, the heat stabilizer is Mg(OH)2.

[0011] Furthermore, in step S1.3, the dissolution temperature is 90℃, and the stirring time is 3-5 hours.

[0012] Furthermore, during the melt extrusion, the screw speed is 1300 rpm and the die temperature is 90℃; the first drafting involves setting a room temperature drafting roller below the spinneret 4, with the roller speed at 300 r / min, to obtain PVA prepolymerized yarn; the second drafting involves drafting the PVA pre-oriented yarn in a pair of hot drafting rollers, with the drafting roller temperature at 130℃ and the drafting ratio at 5, to obtain fully drafted PVA yarn.

[0013] Furthermore, in step S2.1, the PDMS prepolymer and curing agent are mixed at a mass ratio of 10:1, magnetically stirred at room temperature for 30 minutes, and then vacuum degassed.

[0014] Furthermore, in step S2.2, the aqueous PVA filaments are passed through an impregnation tank containing PDMS coating solution, and then the PDMS coating solution is applied to the surface of the aqueous PVA filaments by a sponge filament clamp.

[0015] Furthermore, the sponge wire clamp includes a wire clamp shaft, on which a first pressure adjusting nut, a first pressure adjusting spring, a first washer, a first sponge sheet, a second sponge sheet, a second washer, a second pressure adjusting spring, and a second pressure adjusting nut are sequentially sleeved.

[0016] The present invention also relates to a cooling fabric, wherein the yarn used comprises the cooling PVA filament prepared above.

[0017] The beneficial effects of the present invention are as follows: The melt spinning preparation method of cooling PVA filament and the cooling fabric involved in the present invention adopt the melt spinning method, which makes the preparation of cooling PVA filament more environmentally friendly. Furthermore, by using water as a heat storage system, a long-lasting cooling effect can be achieved through the continuous heat absorption of water, fundamentally solving the dependence of traditional cooling fibers on chemical additives. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the preparation process of cooling PVA filaments; Figure 2 This is a schematic diagram of the preparation process of modified PVA gel; Figure 3 This is a schematic diagram of PDMS coating and sizing of water-containing PVA filaments and a structural schematic diagram of a sponge filament clamp. Figure 4 The diagram shows the structure of a cooling PVA filament; (a) is a macroscopic image; (b) are SEM images of PVA fibers sized with and without PDMS; and (c) is an SEM image of the PDMS film peeled off from the outer layer of the PVA. Figure 5 This is a SEM image of a cooling PVA filament; Figure 6 The figures show a comparison of the surface impregnation properties of the cooling fabric and the control group fabric; (a) dynamic hydrophilicity of the ordinary fabric; (b) static water contact angle of the fabric containing PDMS@PVA cooling fibers. Figure 7 The dynamic transport properties of liquid water in the control group and the cooling fabric; Figure 8 This is a line graph showing the change of surface temperature over time for the control group and the cool-feeling fabric under the action of a hot roller. Figure 9 These are the infrared test results of ordinary fabric and cooling fabric under the action of a heated roller. (a) Ordinary fabric, (b) Cooling fabric. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] Combination Figure 1 , Figure 2 and Figure 3 This invention will be described in detail below. The present invention relates to a melt spinning method for preparing cool-feeling PVA filaments, comprising the preparation of water-containing PVA filaments and PDMS coating sizing. The main raw materials used in this invention are shown in Table 1, and the main equipment used is shown in Table 2.

[0021] Table 1.1 Main Raw Materials and Reagents Table 2 Main Instruments and Equipment The preparation process of the water-containing PVA filament includes melt extrusion, primary drawing, and secondary drawing; the melt extrusion is to heat the modified PVA gel to melt using a screw extruder and extrude it from the spinneret.

[0022] The preparation process of the modified PVA gel includes the following steps: S1.1 Pre-drying: In order to eliminate the influence of raw material moisture on the accuracy of the proportion, PVA particles with a degree of alcoholysis of 99% are placed in a forced-air drying oven and dried at 80°C for 2 hours; PVA particles are high-temperature water-soluble PVA (alcoholysis degree 99%, such as PVA1799), and low-alcoholysis PVA cannot be used. Low-alcoholysis PVA can be water-soluble at medium and low temperatures and is not suitable for making fabrics (such as PVA1788).

[0023] S1.2 Pre-swelling: A water-polyol PGL-dimethyl sulfoxide DMSO ternary compound plasticizing system was constructed according to the specified ratio. Dried PVA particles were weighed and mixed with the ternary compound plasticizing system under stirring conditions, and swelled for a set time in a closed environment at a set temperature. Specifically, the ratio of PVA:H2O:DMSO:PGL was 100:240:60:25. During the addition of the liquid compound plasticizing system, the magnetic stirrer was maintained at a low speed (50-100 r / min) to ensure that the liquid could uniformly coat the surface of the PVA particles. Swelling was carried out in a closed environment at 65℃ for 1-2 h. This step significantly reduced energy consumption in the subsequent dissolution process and prevented localized yellowing due to uneven dissolution. After sufficient swelling, the heat stabilizer Mg(OH)2 was added and stirred evenly. The amount of Mg(OH)2 was 1%-2% of the PVA mass; in this example, 1% was selected.

[0024] S1.3 Dissolution: Transfer the swollen material to a constant-temperature container equipped with a stirrer. Set the dissolution temperature and continue stirring until a colorless, transparent, or slightly milky white, high-viscosity, uniform PVA fluid is formed. Specifically, the dissolution temperature is 90℃, and the stirring time is 3 hours. The rotation speed of the magnetic rotor is 250-300 r / min; speeds higher than this are prone to generating bubbles.

[0025] S1.4 Cooling and Molding: The dissolved PVA fluid is transformed into a solid gel through controlled cooling to facilitate subsequent granulation and feeding. The high-temperature fluid is poured into a pre-made mold and allowed to cool naturally, forming a more uniform and solidified gel during the cooling process.

[0026] S1.5, Pelletizing: The solid gel formed in the previous step is pelletized to form gel particles. Specifically, a pelletizer, cutter, scissors, or other means are used to cut the gel block into regular gel particles of about 2-4 mm, which are used for the next step of melt extrusion.

[0027] In this invention, a two-step roller drawing process is used. Melt extrusion involves adding PVA gel chips into the extrusion hopper. Under the shearing and heating action of the screw extruder, the PVA gel melts and is extruded from the spinneret. During this process, the screw speed is 1300 rpm and the die temperature is 90°C. The first drawing involves placing a room-temperature drawing roller 40 cm below the spinneret at a speed of 300 r / min. The PVA melt undergoes a first cold drawing on the roller to obtain PVA pre-oriented yarn (PVA-POY). The second drawing involves feeding the PVA filament wound on the room-temperature roller to a pair of hot drawing rollers for a second hot drawing (roller temperature 130°C, draw ratio 5), resulting in fully drawn PVA yarn (PVA-FDY). At this point, the water content of the PVA-FDY is approximately 50%, and the diameter of the water-containing PVA-FDY is approximately 300 μm.

[0028] The PDMS coating and sizing process includes the following steps: S2.1 Preparation of PDMS coating solution: Mix PDMS prepolymer and curing agent at a mass ratio of 10:1 and stir to form a PDMS coating solution. The PDMS prepolymer is vinyl-terminated polydimethylsiloxane (Sylgard 184 A), and the curing agent is a uniformly mixed mixture of hydrogen-containing silicone oil and platinum complex catalyst (Sylgard 184 B) at a weight ratio of 10:1. Of course, other compounding ratios can be selected according to actual needs.

[0029] S2.2 Sizing: PDMS coating solution is applied to the surface of the water-containing PVA filaments. Specifically, the water-containing PVA filaments are passed through an impregnation tank containing PDMS coating solution, and then through a sponge clamp to attach the PDMS coating solution to the surface of the water-containing PVA filaments. The sponge clamp includes a clamp shaft 1, on which a first pressure adjusting nut 2, a first pressure adjusting spring 3, a first washer 4, a first sponge sheet 5, a second sponge sheet 6, a second washer 7, a second pressure adjusting spring 8, and a second pressure adjusting nut 9 are sequentially mounted. The impregnated water-containing PVA filaments are placed between the first sponge sheet 5 and the second sponge sheet 6, and the pressure provided by the springs causes a certain amount of PDMS coating solution to adhere to the surface of the water-containing PVA filaments.

[0030] S2.3 Curing: The aqueous PVA filaments coated with PDMS coating solution are cured at a curing temperature for a certain time to obtain cooling PVA filaments. Specifically, the aqueous PVA filaments coated with PDMS coating solution are sent into a hot air circulating oven and cured at 80°C for 15 min to allow the PDMS prepolymer to be completely cross-linked and cured, forming a continuous and dense hydrophobic coating layer on the fiber surface. Finally, a cooling PVA filament with a core layer of high water content PVA and a skin layer of PDMS hydrophobic film is obtained, wherein the diameter of the aqueous PVA filament is 300 μm and the thickness of the PDMS hydrophobic film is approximately 13 μm.

[0031] This invention also relates to a cooling fabric, which is prepared as a plain weave fabric using a semi-automatic sample loom or other types of looms. A 65 / 35 polyester / cotton blended yarn (20 count) is used as the warp yarn, and cooling PVA filament is used as the weft yarn. The weaving parameters are: warp density 320 ends / 10 cm, weft density 280 ends / 10 cm, and fabric width 5 cm (referred to as: cooling fabric). As a blank control group (referred to as: ordinary fabric), a fabric of the same size is woven using 65 / 35 polyester / cotton blended yarn as both warp and weft yarns.

[0032] The following tests need to be performed on the prepared cooling PVA filament fabric: (1) Fiber morphology analysis: The surface and cross-sectional morphology of the fiber were observed using a scanning electron microscope. Before the test, the sample was sputtered with gold for 20 seconds.

[0033] (2) Mechanical property test: The tensile properties of the fiber were tested using a universal tensile testing machine, referring to GB / T14344-2008 "Test method for tensile properties of chemical fiber filament".

[0034] (3) Water-locking test of PDMS@PVA fiber: The dynamic transfer characteristics of liquid moisture in the fabric were tested using a liquid moisture management instrument. The duration of a single test was 2 minutes.

[0035] (4) Cooling performance test of fabric: The surface temperature change of the fabric on the hot roller within 45 seconds was recorded in real time by infrared thermal imager (the hot roller is the same as the secondary stretching equipment used in the preparation of water-containing PVA filament), the infrared display temperature at different times was recorded, the temperature rise curve was plotted, and its transient and continuous cooling performance was characterized.

[0036] (5) Water contact angle test: The hydrophilic / water repellent properties of the fabric were determined in accordance with GB / T42694—2023 "Detection and evaluation of the anti-wetting properties of textile surfaces - contact angle and roll-off angle".

[0037] Combination Figure 4 and Figure 5The structure of the cooling PVA filament is described. (a) shows the macroscopic fiber morphology after PDMS coating, (b) shows SEM images of sized and unsized PVA fibers, and (c) shows the SEM image after PDMS removal. It can be seen that the surface of the PDMS-coated cooling PVA filament is smooth, the PDMS coating is uniformly distributed on the fiber surface with no significant thickness difference, no obvious agglomeration or defects, and it can form a stable water-locking structure, effectively inhibiting the evaporation and loss of moisture in the core layer. The thickness of the PDMS hydrophobic film in the cooling PVA filament is 13 micrometers.

[0038] The mechanical properties of the cooling PVA filaments were tested, and the test structure is shown in Table 3.

[0039] Table 3 Mechanical properties of PVA cooling fiber The results showed that the average tensile strength of the filaments was greater than 8 MPa, and the elastic modulus was above 1000 MPa, exhibiting excellent rigidity and tensile properties, which can meet the mechanical performance requirements of subsequent weaving processing. The results also showed that the fiber elongation at break was very low (less than 1%), exhibiting certain brittle characteristics. This property mainly stems from two changes in the fiber preparation process: firstly, the high moisture content affects the crystalline structure of the PVA fibers, limiting their deformation capacity; secondly, although the PVA fibers in the core layer have a certain elongation at break, their overall extensibility is poor after being combined with the outer PDMS layer.

[0040] The water-repellent properties of the prepared cooling fabric were analyzed, including surface wetting properties and fabric water-locking properties. Figure 6 As can be seen, droplets penetrate quickly into ordinary fabrics, failing to form a stable water contact angle (as shown in Figure (a)). In contrast, the cooling fabric exhibits better water repellency, with a static water contact angle of 111.6°. This is due to the strong water repellency of PDMS, which improves the overall water repellency of the fabric.

[0041] Figure 7The dynamic transfer performance of liquid water in fabrics tested by a liquid moisture management instrument is shown in the figure (UT inside: representing the skin-contact side of the fabric, UB outside: representing the environmental side of the fabric). As shown in Figure (a), for ordinary fabrics, the moisture content of both the UB outside and UT inside begins to rise sharply at around 12 seconds, indicating that the fabric rapidly absorbs moisture. It can also be seen that the rise speed of the UB outside curve is faster than that of the UT inside curve, and the peak value is also higher, indicating that ordinary fabrics have a one-way moisture-wicking function, drawing moisture from the skin side to the outside of the garment, keeping the skin-contact side relatively dry. After reaching the peak, both curves show a slow downward trend, indicating that moisture begins to diffuse to the surrounding area. As shown in Figure (b), for the cooling fabric, the UB outside and UT inside curves remain at 0 throughout the entire 120-second test cycle, indicating that the instrument's sensor did not detect moisture absorption or conduction, reflecting that the cooling fabric is hydrophobic, which is consistent with... Figure 5 The results of the water contact angle test were consistent, which also indicates that PDMS can effectively lock in the moisture inside PVA.

[0042] Analysis of the cooling properties of cooling fabrics. Figure 8 The image shows the trend of fabric surface temperature change over time as obtained from infrared thermal imaging. It can be seen that under constant-temperature heating, the surface temperature of ordinary fabric rapidly rises to 25.5℃ at 5 seconds, continues to increase to 30℃ within 5-15 seconds, and then the heating rate slows down, reaching 32.7℃ at 45 seconds. In contrast, the surface temperature of the cooling fabric rises to 15.7℃ within 5 seconds, and the heating rate accelerates between 5 and 30 seconds, reaching 32.6℃ at 45 seconds (the same as the ordinary fabric). Figure 9 The demonstration showcased the actual testing process using an infrared imager. The temperature rise curves of both fabrics showed that, within 30 seconds, the cooling fabric experienced a significantly lower temperature rise than the ordinary fabric. The core reason for this is that the water-based medium in the fiber core layer possesses a high specific heat capacity, continuously absorbing heat during the heating process and slowing down the rise in fabric surface temperature, thus exhibiting significant resistance to external heat intrusion.

[0043] This invention relates to the preparation of cooling PVA filaments by coating them with water-containing PVA filaments using a sizing method and a water-repellent PDMS material. Cooling fabrics are then prepared through fabric weaving. By fully utilizing the strong hydrophilic properties of PVA melt-spun fibers, and combining the preparation of high-water-content PVA fibers with a PDMS surface coating process, a continuous, uniform, and microporous / gap-free hydrophobic skin can be formed on the fiber surface. This successfully prepares a water-medium PVA fiber with a high-water-content core and a hydrophobic skin structure of PDMS@water-containing PVA. The cooling fabric prepared from the PVA cooling filaments exhibits a significant cooling effect and possesses excellent hydrophobic and impermeable capabilities.

Claims

1. A method for preparing cool-feeling PVA filaments by melt spinning, characterized in that, This includes the preparation of water-containing PVA filaments and PDMS coating and sizing; The preparation process of the water-containing PVA filament includes melt extrusion, primary drawing, and secondary drawing; The melt extrusion process involves heating the modified PVA gel to a melt using a screw extruder and extruding it through a spinneret. The preparation process of the modified PVA gel includes the following steps: S1.1 Pre-drying: Place PVA particles with a degree of alcoholysis of 99% in an oven for drying; S1.2 Pre-swelling: Construct a water-polyol-dimethyl sulfoxide ternary compound plasticizing system according to the proportion. Weigh the dried PVA particles and mix them with the ternary compound plasticizing system under stirring conditions. Swell for a set time in a closed environment at a set temperature. After swelling, add a heat stabilizer. S1.3 Dissolution: Transfer the swollen material to a constant temperature container equipped with a stirring device, set the dissolution temperature, and continuously stir to form PVA fluid; S1.4 Cooling and molding: Cooling the dissolved PVA fluid into a solid gel; S1.5, Pelletizing: The solid gel formed in the previous step is granulated to form gel particles; The PDMS coating and sizing process includes the following steps: S2.1 Preparation of PDMS coating solution: The PDMS coating solution is formed by mixing and stirring PDMS prepolymer and curing agent; S2.2 Sizing: PDMS coating solution is applied to the surface of water-containing PVA filaments; S2.3 Curing: The aqueous PVA filaments coated with PDMS coating liquid are cured at the curing temperature for a certain time to obtain cool-feeling PVA filaments.

2. The melt spinning method for preparing cool-feeling PVA filament according to claim 1, characterized in that, In step S1.1, the PVA particles are dried at 80°C for 2 hours.

3. The melt spinning method for preparing cool-feeling PVA filament according to claim 1, characterized in that, In step S1.2, the ratio of PVA:water:polyol:dimethyl sulfoxide by weight is 100:240:60:

25.

4. The melt spinning method for preparing a cooling PVA filament according to claim 1, characterized in that, In step S1.2, the swelling is performed in a closed environment at 60°C for 1-2 hours.

5. The melt spinning method for preparing a cooling PVA filament according to claim 1, characterized in that, The heat stabilizer is Mg(OH)2.

6. The method for preparing a cooling PVA filament by melt spinning according to claim 1, characterized in that, In step S1.3, the dissolution temperature is 90℃ and the stirring time is 3-5 hours.

7. The method for preparing a cooling PVA filament by melt spinning according to claim 1, characterized in that, During melt extrusion, the screw speed is 1300 rpm and the die temperature is 90℃; the first drafting is performed by setting a room temperature drafting roller below the spinneret, with the roller speed at 300 r / min, to obtain PVA prepolymerized yarn; the second drafting is performed by drafting the PVA pre-oriented yarn in a pair of hot drafting rollers, with the temperature of the drafting rollers at 130℃ and the drafting ratio at 5, to obtain fully drafted PVA yarn.

8. The melt spinning method for preparing a cooling PVA filament according to claim 1, characterized in that, In step S2.1, the PDMS prepolymer and curing agent are mixed at a mass ratio of 10:1, magnetically stirred at room temperature for 30 minutes, and then vacuum degassed.

9. The method for preparing a cooling PVA filament by melt spinning according to claim 1, characterized in that, In step S2.2, the aqueous PVA filaments are passed through an impregnation tank containing PDMS coating solution, and then the PDMS coating solution is applied to the surface of the aqueous PVA filaments by a sponge filament clamp.

10. The melt spinning method for preparing a cooling PVA filament according to claim 8, characterized in that, The sponge wire clamp includes a wire clamp shaft, on which a first pressure adjusting nut, a first pressure adjusting spring, a first washer, a first sponge sheet, a second sponge sheet, a second washer, a second pressure adjusting spring, and a second pressure adjusting nut are sequentially sleeved.

11. A cooling fabric, characterized in that, The yarn used includes the cooling PVA filament prepared according to any one of claims 1 to 9.

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