A high-strength polyester fiber for outdoor use with radiative cooling function and its preparation method

Abstract

This invention provides a high-strength polyester fiber for outdoor use with radiative cooling function. The preparation method includes the following steps: titanium dioxide, silicon dioxide, silicon carbide, and zirconium phosphate are blended and ground in a certain proportion, dispersed in an acetone solution with a dispersant added, and then ultrasonically treated to form a nanoparticle dispersion; the nanoparticle dispersion is mixed with polyester chips; the mixed composite material is fed into a screw extruder for melt blending to form a spinning solution; the spinning solution is precisely metered by a metering pump and extruded through a spinneret to form fiber bundles, the spinneret being equipped with a slow-cooling heating device; the fiber bundles are post-treated to obtain high-strength polyester fibers. This invention selects a specific combination of titanium dioxide, silicon dioxide, silicon carbide, and zirconium phosphate, combined with specific slow-cooling technology and high-ratio stretch setting, to give the fiber excellent radiative cooling performance and mechanical strength, which can be widely used in outdoor clothing, awnings, car covers, and other fields.

Description

Technical Field

[0001] This invention relates to the field of functional polyester fiber preparation technology, and in particular to a high-strength outdoor polyester fiber with radiative cooling function and its preparation method. Background Technology

[0002] Polyester fiber is widely used due to its high strength, good abrasion resistance, and low cost. However, traditional polyester fiber has poor moisture absorption and breathability, and tends to retain heat when used outdoors or in high-temperature environments, resulting in poor thermal comfort for the human body.

[0003] Radiation cooling technology is a zero-energy cooling method that achieves radiation heat dissipation to the environment by enhancing the high reflectivity of objects in the solar spectrum (0.3-2.5 μm) and the high emissivity in the mid-infrared atmospheric window band (8-13 μm).

[0004] Currently, the mainstream approach to applying radiation cooling technology to textiles has significant limitations:

[0005] 1. Functional fiber pathway:

[0006] For example, the prior art discloses a radiation-cooling fiber, its preparation method, and its application (CN 112853522 A). The preparation method involves mixing inorganic micro / nano particles and a substrate material to obtain a spinning solution of micro / nano particles and a substrate material; then, the spinning solution of micro / nano particles and a substrate material is subjected to dry-wet spinning to obtain radiation-cooling fibers. Preferably, the inorganic micro / nano particles are titanium dioxide, zinc oxide, or silicon nitride, and the polymer substrate material is preferably cellulose, polyacrylonitrile, polyvinyl alcohol, or chitosan. These preferred materials are natural polymers or hydrophilic polymers, suitable for use with hydrophilic substrates to prepare radiation-cooling fibers via dry-wet spinning, resulting in excellent radiation-cooling effects. However, the mechanical properties of the substrate material itself or the resulting fibers, especially their strength, are far below the standards for industrial polyester filaments, failing to meet the requirements for outdoor or high-temperature environments.

[0007] Although the scheme mentions polyethylene terephthalate (PET), also known as polyester, in a broad range of substrate materials, polyester is a typical hydrophobic and highly crystalline polymer. There is no obvious solvent that can dissolve it at room temperature or near room temperature to prepare a solution suitable for wet and dry spinning, which presents process compatibility issues. If a strongly polar or acidic solvent is used, there will be problems such as deterioration of inorganic micro-nano particle dispersion and loss of mechanical properties.

[0008] 2. Functional coating path:

[0009] For example, the prior art discloses a radiation-cooling bilayer nanocoating (CN 105348892 A). The upper layer of this coating is a reflective nanoparticle layer formed by nanoparticles with a particle size range of 200-1000 nm, and the lower layer is an emitting nanoparticle layer formed by nanoparticles with a particle size range of 40-100 nm. The reflective nanoparticle layer contains one or more of TiO2, ZnO, ZnS, ZrO2, or Y2O3, and the emitting nanoparticle layer contains one or more of SiC, SiO2, and BN. This radiation-cooling bilayer nanocoating has significant application value in building energy conservation, electronic device heat dissipation, and food preservation. However, its technical field differs fundamentally from that of the textile fiber field, and the material system and processing technology are incompatible. This coating is difficult to bond with polyester fiber matrix, has insufficient firmness, and its function will significantly degrade during use.

[0010] Existing technology also discloses a multifunctional protective coating material for fair-faced concrete and its preparation method. This material adds nano-phosphates as functional fillers to a resin coating, utilizing the high emissivity of phosphates in the 8-13μm atmospheric window band to achieve radiative heat dissipation. The nano-phosphates are nano-aluminum phosphate, nano-zinc phosphate, nano-zirconium phosphate, and nano-yttrium phosphate. This technology belongs to the field of concrete protection and differs fundamentally from the textile industry. If used on polyester, it would suffer from poor washability, poor fabric feel, reduced breathability, and a short functional lifespan.

[0011] Other methods, such as embedding functional particles into the fiber through blend spinning, can solve the durability problem, but nanoparticles are prone to agglomeration in high-temperature and high-viscosity polymer melts, resulting in problems such as poor spinnability, reduced fiber strength, and functional failure.

[0012] In summary, existing technologies cannot provide a polyester fiber that can be prepared through melt spinning process, possessing both long-lasting and efficient radiation cooling function and maintaining high strength.

[0013] Therefore, the technical problem to be solved by this invention is to provide a preparation method based on melt spinning, which overcomes the technical bottlenecks caused by the introduction of various functional nanoparticles during high-temperature melt spinning, such as deterioration of spinnability and significant decrease in fiber strength, to obtain radiation-cooled polyester fibers with excellent radiation cooling function and mechanical properties. Summary of the Invention

[0014] This invention provides a high-strength polyester fiber for outdoor use with radiative cooling function and its preparation method. By combining a specific combination of nanoparticles with an optimized melt spinning process, multiple functional nanoparticles are uniformly dispersed inside the fiber to obtain a polyester fiber with both long-lasting radiative cooling and excellent mechanical properties.

[0015] The present invention adopts the following technical solution:

[0016] A method for preparing high-strength polyester fiber for outdoor use with radiative cooling function includes the following steps:

[0017] S1. Preparation of radiation-cooled nanoparticles: By weight, take 2-5 parts of titanium dioxide, 5-10 parts of silicon dioxide, 1-3 parts of silicon carbide, and 1-3 parts of zirconium phosphate, mix them together, and grind them with a ball mill to obtain a uniform powder; add the uniform powder to a small amount of acetone solution, add a dispersant, and ultrasonically vibrate for 20 minutes to form a stable dispersion of radiation-cooled nanoparticles.

[0018] S2. Blending: The radiation-cooling nanoparticle dispersion prepared in step S1 is mixed with untackified polyester chips, wherein the mass of the solid functional powder contained in the radiation-cooling nanoparticle dispersion is 1.5%-3.5% of the mass of the polyester chips;

[0019] S3. Melting and Deviation: The mixed material is fed into a screw extruder and melt-blended at a temperature of 270℃-290℃. The acetone solvent is removed by the vacuum deviation device configured in the extruder to form a uniform spinning solution.

[0020] S4. Spinning and slow cooling: After the spinning solution is precisely metered by the metering pump, it is extruded by the spinneret to form fiber bundles. A slow cooling heating device is installed below the spinneret. The temperature of the slow cooling heating device is controlled to be 8℃-12℃ higher than the surface temperature of the spinneret. The surface temperature of the spinneret is controlled between 275℃ and 300℃.

[0021] S5. Post-processing: The fiber bundle is cooled by ring blowing, oiled, pre-networked, stretched and shaped by multi-stage hot rollers, and then wound into a cylinder to obtain the high-strength polyester fiber.

[0022] Furthermore, in step S1, the dispersant is a silane coupling agent KH-550 or KH-560.

[0023] Furthermore, in step S5, the cooling air temperature of the ring blowing cooling process is 19-21℃, the humidity is 70-80%RH, and the wind speed is 0.6-0.8 m / min.

[0024] Furthermore, in step S5, the oiling process uses dual oil nozzles for oiling, with an oiling rate of 0.8%-0.9%.

[0025] Furthermore, the stretching and shaping is performed using three pairs of hot rollers, with temperatures set at 80-100℃, 110-130℃, and 200-220℃ respectively, and a total stretching ratio of 4.5-5.5.

[0026] Furthermore, in step S5, the winding speed of the winding process is 2300-2500 m / min.

[0027] An outdoor high-strength polyester fiber with radiative cooling function, prepared by the above method, wherein the tensile strength of the high-strength polyester fiber is not less than 7.0 cN / dtex.

[0028] A textile comprising the above-mentioned high-strength polyester fiber for outdoor use with radiative cooling function.

[0029] The beneficial effects of this invention, which discloses a high-strength polyester fiber for outdoor use with radiative cooling function and its preparation method, are as follows:

[0030] 1. A specific combination of titanium dioxide, silicon dioxide, silicon carbide and zirconium phosphate (TiO2-SiO2-SiC-ZrP) is selected. Titanium dioxide and silicon dioxide provide efficient solar light scattering, while silicon carbide and zirconium phosphate synergistically enhance the infrared emissivity of the fiber in the atmospheric window band (8-13μm). The synergistic effect of this quaternary combination gives the fiber efficient and balanced radiative cooling performance, which is superior to the simple combination of hydrophilic substrate and inorganic micro-nano particles.

[0031] 2. By controlling the low addition amount of solid functional powder (1.5%-3.5%), and using specific slow cooling technology and high stretch setting, the fiber has excellent radiative cooling performance while achieving unexpected mechanical strength (≥7.0 cN / dtex).

[0032] 3. Since the nanoparticles are embedded inside the fiber through blend spinning rather than as a surface coating, the products made from this fiber are resistant to washing, friction, and light exposure, and have long-lasting functionality, thus solving the durability problem of functional coating paths in existing technologies.

[0033] 4. Based on the mainstream melt spinning process, it creatively integrates vacuum devolatilization and slow cooling heating devices, which can be directly modified and promoted on existing industrial equipment, and has cost and efficiency advantages. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a method for preparing outdoor high-strength polyester fiber with radiative cooling function according to the first embodiment of the present invention;

[0035] Figure 2 This is a morphology diagram of the composite material after blending in the first embodiment of the present invention. Detailed Implementation

[0036] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more explicit definition of the scope of protection of the present invention. However, the scope of protection of the present invention is not limited thereto.

[0037] In the first embodiment, high-strength polyester fiber for outdoor use with radiative cooling function is prepared using the following steps:

[0038] S1. Preparation of radiation-cooled nanoparticles: Take 3 parts of titanium dioxide, 7 parts of silicon dioxide, 2 parts of silicon carbide, and 2 parts of zirconium phosphate, and ball mill them together to obtain a uniform powder. Slowly add the uniform powder to an appropriate amount of acetone solvent (solid-liquid ratio of 1:15), and add 1.0% of the total mass of the powder of silane coupling agent KH-550 as a dispersant and surface modifier. Place the mixture in an ultrasonic cell disruptor and treat it with ultrasonic vibration at 600W power for 20 minutes to form a radiation-cooled nanoparticle dispersion. In this process, the ultrasonic cavitation effect can effectively break the soft agglomeration of nanoparticles. At the same time, the alkoxy groups of KH-550 molecules react with the hydroxyl groups on the particle surface, and the long-chain organic groups at the other end improve the compatibility of the particles with the subsequent polyester matrix.

[0039] S2. Blending: The above nanoparticle dispersion is uniformly added to polyester chips with an intrinsic viscosity of 0.65 dl / g that have not undergone thickening treatment. By controlling the amount of dispersion added, the mass of solid functional powder contained in the nanoparticle dispersion is 1.5% of the mass of polyester chips. The mixture is placed in a high-speed mixer and premixed at 800 rpm for 5 minutes to ensure that the initial dispersion is uniform.

[0040] S3. Melting and Deviation: The mixture is melt-blended in a screw extruder at 285°C, and acetone is removed by vacuum devolatilization (the system vacuum is maintained at -0.095 MPa) to obtain the spinning solution. The vacuum devolatilization can completely extract and recover the acetone solvent added in step S1 and any trace amounts of water that may be present, effectively preventing the solvent from vaporizing and causing bubble fibers in the subsequent high-temperature spinning, and also avoiding the hydrolysis and degradation of the polyester polymer, thus ensuring the purity and stability of the spinning solution.

[0041] S4. Spinning and Slow Cooling: After the spinning solution is precisely metered by the metering pump, it is extruded through a 36-hole spinneret to form fiber bundles. The surface temperature of the 36-hole spinneret is controlled at 295℃. The slow cooling heating device, which is set 5mm directly below the spinneret, is a ring-shaped hollow metal shell with hot air flowing inside (the hot air is regulated by a precision temperature control system). Its temperature is precisely controlled and stabilized at 307℃ (i.e., 12℃ higher than the surface temperature of the spinneret). The function of this slow cooling zone is to provide a high-temperature buffer zone for the fiber bundles after they leave the spinneret, which can significantly slow down the cooling rate of the melt stream.

[0042] S5. Cooling and oiling: The fiber bundles are cooled by a ring blower (air temperature 20℃, humidity 75%RH, air speed 0.7m / min), and then oiled with polyester oiling agent through a double oil nozzle. The oiling rate is 0.85%, which reduces the unevenness of the fiber bundles and improves production stability.

[0043] S6. Pre-networking: The oiled fiber bundles are pre-networked by a pre-networker.

[0044] S7. Stretching and Shaping: Three pairs of rollers are used to stretch and shape the pre-networked fiber bundles. The stretching ratio is 5.0. The temperatures of the three pairs of rollers are set to 90℃, 120℃ and 210℃ respectively, so as to make the fiber bundles have good uniformity and improve the mechanical properties of the fiber bundles.

[0045] S8. Main network: The stretched and shaped fiber bundles are networked by the main networker.

[0046] S10, Winding: The fiber bundles passing through the main network are wound automatically at a speed of 2400m / min to avoid unwinding difficulties and obtain high-strength polyester fibers for outdoor use with radiative cooling function.

[0047] In addition, the specific selection of each component in step S1 is as follows: 2 parts of titanium dioxide (rutile type, average particle size 300nm), silicon dioxide (amorphous, average particle size 500nm), silicon carbide (β type, average particle size 800nm), and zirconium phosphate (crystalline type, average particle size 600nm).

[0048] In the second embodiment, high-strength polyester fiber for outdoor use with radiative cooling function is prepared using the following steps:

[0049] S1. Preparation of radiation-cooled nanoparticles: Take 4 parts of titanium dioxide, 9 parts of silicon dioxide, 2.5 parts of silicon carbide, and 2.5 parts of zirconium phosphate, and ball mill them together to obtain a uniform powder. Add the powder to an acetone solution, and add 1% of KH-550 silane coupling agent by weight of the powder. Sonicate for 20 minutes to form a dispersion of radiation-cooled nanoparticles.

[0050] S2. Blending: The above nanoparticle dispersion is mixed with polyester chips so that the mass of the solid functional powder contained in the nanoparticle dispersion is 3% of the mass of the polyester chips;

[0051] S3. Melting and Deviation: The blended composite material is fed into a screw extruder and melt-blended at 280°C. Acetone is then removed by vacuum devolatilization to obtain the spinning solution.

[0052] S4. Spinning and slow cooling: After the spinning solution is precisely metered by the metering pump, it is extruded through a 36-hole spinneret to form fiber bundles. The surface temperature of the 36-hole spinneret is controlled at 290℃, and the temperature of the slow cooling heating device is controlled at 300℃ (10℃ higher).

[0053] S5. Cooling and oiling: The fiber bundles are cooled by a ring blower (air temperature 20℃, humidity 75%RH, air speed 0.6m / min), and then oiled with polyester oil through a double oil nozzle, with an oiling rate of 0.85%.

[0054] S6. Pre-networking: The oiled fiber bundles are pre-networked by a pre-networker.

[0055] S7. Stretching and setting: The pre-networked fiber bundle is stretched and set using three pairs of rollers with a stretching ratio of 5.0. The temperatures of the three pairs of rollers are set to 90℃, 120℃ and 210℃ respectively.

[0056] S8. Main network: The stretched and shaped fiber bundles are networked by the main networker.

[0057] S10, Winding: The fiber bundles passing through the main network are automatically wound at a speed of 2400m / min to obtain high-strength polyester fibers.

[0058] In the first comparative example, no radiation-cooled nanoparticles were added. The preparation steps were: melting and devolatilization, spinning and slow cooling, cooling, oiling, pre-networking, stretching and shaping, main networking and winding. The preparation conditions were the same as in the first embodiment.

[0059] In the second comparative example, zirconium phosphate was not added during the preparation of the radiation-cooled nanoparticles. The other three components (titanium dioxide, silicon dioxide, and silicon carbide) were increased proportionally, that is, the initial ratio of TiO2, SiO2, and SiC in the nanoparticles (3:7:2) remained unchanged, and the mass of the solid functional powder was still 1.5% of the mass of the polyester chips. The other preparation conditions were the same as in the first example.

[0060] In the third comparative example, no slow cooling heating device is set in step S4, the surface temperature of the spinneret is the same as in the first embodiment, and the preparation steps are: preparation of radiation-cooled nanoparticles, blending, melting and devolatilization, spinning, cooling, oiling, pre-networking, stretching and shaping, main networking and winding, and the preparation conditions are the same as in the first embodiment.

[0061] The polyester fibers prepared in the first embodiment, second embodiment, first comparative example, second comparative example, and third comparative example were used to manufacture fabrics with a plain weave structure. The radiation cooling performance of the fabrics was tested, and the radiation cooling performance and fiber strength are shown in the table below:

[0062]

[0063] Cooling temperature refers to the peak temperature drop of simulated skin covered by the fabric woven from the fibers of this invention compared to the exposed environment under a standard solar simulator (irradiance 1000 W / m²).

[0064] It can be seen from the above table:

[0065] In the first comparative example, the fiber strength obtained without the addition of radiation-cooling nanoparticles was between 7.3 and 7.6 cN / dtex, and the cooling effect was only 2-2.5℃. In the first and second embodiments, the radiation-cooling performance of the fabric increased with the increase of the composite material concentration. From the perspective of mechanical properties, the addition of composite materials had little impact on fiber properties, and the fiber strength was slightly reduced.

[0066] The second comparative example, without the addition of zirconium phosphate, showed that although the fiber strength remained at 7.0 cN / dtex, the cooling effect was only about 3.5℃, demonstrating that the synergistic effect of this specific combination of titanium dioxide, silicon dioxide, silicon carbide, and zirconium phosphate is crucial to the cooling performance of the fiber.

[0067] The third comparative example shows that without the use of a slow cooling and heating device, the breakage rate during spinning increases significantly, and the strength of the resulting fiber decreases to about 6 cN / dtex, with uneven yarn distribution. This demonstrates that a slow cooling and heating device is a necessary condition to ensure that the fiber is spinnable and to guarantee its high strength.

[0068] The beneficial effects of this invention, which discloses a high-strength polyester fiber for outdoor use with radiative cooling function and its preparation method, are as follows:

[0069] 1. A specific combination of titanium dioxide, silicon dioxide, silicon carbide and zirconium phosphate (TiO2-SiO2-SiC-ZrP) is selected. Titanium dioxide and silicon dioxide provide efficient solar light scattering, while silicon carbide and zirconium phosphate synergistically enhance the infrared emissivity of the fiber in the atmospheric window band (8-13μm). The synergistic effect of this quaternary combination gives the fiber efficient and balanced radiative cooling performance, which is superior to the simple combination of hydrophilic substrate and inorganic micro-nano particles.

[0070] 2. By controlling the low addition amount of solid functional powder (1.5%-3.5%), and using specific slow cooling technology and high stretch setting, the fiber has excellent radiative cooling performance while achieving unexpected mechanical strength (≥7.0 cN / dtex).

[0071] 3. Since the nanoparticles are embedded inside the fiber through blend spinning rather than as a surface coating, the products made from this fiber are resistant to washing, friction, and light exposure, and have long-lasting functionality, thus solving the durability problem of functional coating paths in existing technologies.

[0072] 4. Based on the mainstream melt spinning process, it creatively integrates vacuum devolatilization and slow cooling heating devices, which can be directly modified and promoted on existing industrial equipment, and has cost and efficiency advantages.

[0073] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing high-strength polyester fiber for outdoor use with radiative cooling function, characterized in that, Includes the following steps: S1. Preparation of radiation-cooled nanoparticles: By weight, take 2-5 parts of titanium dioxide, 5-10 parts of silicon dioxide, 1-3 parts of silicon carbide, and 1-3 parts of zirconium phosphate, mix them together, and grind them with a ball mill to obtain a uniform powder; add the uniform powder to a small amount of acetone solution, add a dispersant, and ultrasonically vibrate for 20 minutes to form a stable dispersion of radiation-cooled nanoparticles. S2. Blending: The radiation-cooling nanoparticle dispersion prepared in step S1 is mixed with untackified polyester chips, wherein the mass of the solid functional powder contained in the radiation-cooling nanoparticle dispersion is 1.5%-3.5% of the mass of the polyester chips; S3. Melting and Deviation: The mixed material is fed into a screw extruder and melt-blended at a temperature of 270℃-290℃. The acetone solvent is removed by the vacuum deviation device configured in the extruder to form a uniform spinning solution. S4. Spinning and slow cooling: After the spinning solution is precisely metered by the metering pump, it is extruded by the spinneret to form fiber bundles. A slow cooling heating device is installed below the spinneret. The temperature of the slow cooling heating device is controlled to be 8℃-12℃ higher than the surface temperature of the spinneret. The surface temperature of the spinneret is controlled between 275℃ and 300℃. S5. Post-processing: The fiber bundle is cooled by ring blowing, oiled, pre-networked, stretched and shaped by multi-stage hot rollers, and then wound into a cylinder to obtain the high-strength polyester fiber.

2. The method for preparing a high-strength polyester fiber for outdoor use with radiative cooling function according to claim 1, characterized in that, In step S1, when the uniform powder is added to the acetone solvent, the solid-liquid ratio is 1:

15.

3. The method for preparing a high-strength polyester fiber for outdoor use with radiative cooling function according to claim 1, characterized in that, In step S1, the dispersant is a silane coupling agent KH-550 or KH-560.

4. The method for preparing a high-strength polyester fiber for outdoor use with radiative cooling function according to claim 1, characterized in that, In step S2, the mixture is placed in a high-speed mixer and premixed for 5 minutes at a speed of 800 rpm.

5. The method for preparing a high-strength polyester fiber for outdoor use with radiative cooling function according to claim 1, characterized in that, In step S5, the cooling air temperature of the ring blowing cooling process is 19-21℃, the humidity is 70-80% RH, and the wind speed is 0.6-0.8 m / min.

6. The method for preparing a high-strength polyester fiber for outdoor use with radiative cooling function according to claim 1, characterized in that, In step S5, the oiling process uses dual oil nozzles for oiling, with an oiling rate of 0.8%-0.9%.

7. The method for preparing a high-strength polyester fiber for outdoor use with radiative cooling function according to claim 1, characterized in that, The stretching and shaping process is carried out using three pairs of hot rollers, with temperatures set at 80-100℃, 110-130℃, and 200-220℃ respectively, and a total stretching ratio of 4.5-5.

5.

8. The method for preparing a high-strength polyester fiber for outdoor use with radiative cooling function according to claim 1, characterized in that, In step S5, the winding speed of the winding process is 2300-2500 m / min.

9. A high-strength polyester fiber for outdoor use with radiative cooling function, prepared by any one of the preparation methods described in claims 1-8, characterized in that, The high-strength polyester fiber has a breaking strength of not less than 7.0 cN / dtex.

10. A textile product, characterized in that, It includes the high-strength polyester fiber for outdoor use with radiative cooling function as described in claim 9.

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