Modified preparation method of PPS short fiber for high-performance high-temperature filter yarn

Abstract

The invention discloses a modification preparation method of PPS short fibers for high-performance high-temperature filter yarns. The method comprises the following steps: (1) raw material blending: uniformly mixing dried PPS resin, a plasticizer, an organic nucleating agent and polyamide resin (PA6) in a high-speed mixer; wherein in terms of 100 parts by weight of the PPS resin, the addition amount of the plasticizer is 2-5 parts by weight, the addition amount of the organic nucleating agent is 0.2-0.8 part by weight, and the addition amount of the polyamide resin (PA6) is 5-15 parts by weight; (2) melt blending granulation; (3) melt spinning; (4) drafting and heat setting; and (5) post-treatment: curling and cutting off to obtain the modified PPS short fiber. The PPS short fiber has the advantages that the PPS short fiber keeps excellent high temperature resistance, chemical corrosion resistance and flame retardance, and also has excellent elongation at break and toughness.

Description

Technical Field

[0001] This invention relates to the field of polymer materials and fiber manufacturing technology, specifically to a method for modifying and preparing polyphenylene sulfide (PPS) short fibers, which is particularly suitable for spinning high-performance high-temperature filter yarns. Background Technology

[0002] Polyphenylene sulfide (PPS) short fibers have excellent high temperature resistance, chemical corrosion resistance and flame retardancy. They are often used to spin high-performance high-temperature filter yarns and are widely used in industrial dust removal filter media, high-temperature filter materials, battery separator supports and other fields.

[0003] However, the PPS short fibers prepared by existing methods still have some drawbacks: (1) High brittleness: PPS crystallizes slowly and is prone to forming large spheroids during spinning, which leads to stress concentration and increased brittleness inside the fiber. This results in low elongation at break of PPS fibers. The elongation at break of ordinary PPS short fibers is usually between 25% and 35%. It lacks impact resistance and flexibility. In complex filtration conditions, such as frequent pulse cleaning and violent shaking of filter media, existing PPS fibers are prone to breakage due to fatigue, which leads to filter media damage and shortens the service life of the filter media. (2) Poor processing performance: The melt viscosity is high and the spinning fluidity is poor. During the spinning process, the yarn is prone to breakage and fuzzing, which affects the spinning efficiency and yarn quality. Summary of the Invention

[0004] The purpose of this invention is to provide a modified preparation method for PPS short fibers for high-performance high-temperature filter yarns. This method combines a specific blending modification formula with an optimized spinning process to improve melt flowability and spinning stability. While maintaining excellent high-temperature resistance, chemical corrosion resistance and flame retardancy, it also significantly improves the elongation at break and toughness of PPS short fibers.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn, comprising the following steps: (1) Raw material blending: The dried PPS resin, plasticizer, organic nucleating agent and polyamide resin (PA6) are uniformly mixed in a high-speed mixer; wherein, based on 100 parts by weight of the PPS resin, the amount of plasticizer added is 2 to 5 parts by weight, the amount of organic nucleating agent added is 0.2 to 0.8 parts by weight, and the amount of polyamide resin (PA6) added is 5 to 15 parts by weight. (2) Melt blending and granulation: The mixture obtained in step (1) is melt blended, extruded, cooled and granulated by a twin-screw extruder to obtain modified PPS masterbatch; (3) Melt spinning: After vacuum drying, the modified PPS masterbatch obtained in step (2) is fed into a screw extruder for melt extrusion to obtain modified PPS melt. The extrusion temperature is controlled at 265-275℃ and the melt pressure is 10-20MPa. The modified PPS melt is then precisely metered by a metering pump and extruded through a spinneret to form nascent fibers. (4) Stretching and heat setting: The nascent fibers are subjected to two-stage stretching and heat setting treatment; wherein, the first-stage stretching ratio is 2.5 to 3.5 times, and the stretching temperature is 80 to 100℃; the second-stage stretching ratio is 1.5 to 2.0 times, and the stretching temperature is 120 to 150℃; the total stretching ratio is controlled at 4.0 to 5.5 times; the heat setting temperature is 160 to 200℃; and the heat setting time is controlled at 20 to 60 seconds. (5) Post-processing: After curling and cutting, modified PPS short fibers are obtained.

[0006] Furthermore, in the aforementioned method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn, the plasticizer is one of triphenyl phosphate (TPP) and dioctyl phthalate (DOP).

[0007] Furthermore, in the aforementioned method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn, the organic nucleating agent is one of sorbitol-based organic nucleating agents and sodium benzoate.

[0008] Furthermore, in the aforementioned method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn, the sorbitol-based organic nucleating agent is selected as dibenzyl sorbitol (DBS).

[0009] Furthermore, in the aforementioned method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn, in step (2), the twin-screw extruder is divided into 5 temperature zones along the material conveying direction: feeding zone 260-270℃, melting zone 270-280℃, mixing zone 280-285℃, homogenizing zone 275-280℃, and die head zone 265-275℃; the screw speed is 200-300 rpm.

[0010] Furthermore, in the aforementioned method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn, in step (3), the cross-sectional shape of the spinneret micro-orifice is circular, the diameter of the spinneret micro-orifice is 0.33-0.35 mm, and the aspect ratio of the spinneret micro-orifice is (3-4):1.

[0011] Furthermore, in the aforementioned method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn, in step (4), a gradient temperature is used during the heat setting process: 160℃→180℃→200℃, with each stage held for 10 to 20 seconds.

[0012] The beneficial effects of this invention are: by combining a specific blending modification formula with an optimized spinning process, the melt viscosity is effectively reduced, the stability of the spinning process is improved, the phenomenon of broken fibers and fuzzy fibers is greatly reduced, the production efficiency and yarn quality are improved, and while maintaining the excellent high temperature resistance, chemical corrosion resistance and flame retardancy of PPS short fibers, its breaking elongation and toughness are significantly improved, so that PPS short fibers have sufficient impact resistance and flexibility, are not easy to break due to fatigue, and can adapt to complex filtration conditions that require high temperature, high strength and high toughness. Attached Figure Description

[0013] Figure 1 This is a top view of the spinneret in this invention.

[0014] Figure 2 This is a cross-sectional view of the spinneret in this invention. Detailed Implementation

[0015] A method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn includes the following steps: (1) Raw material blending: The dried PPS resin, plasticizer, organic nucleating agent and polyamide resin (PA6) are uniformly mixed in a high-speed mixer; wherein, based on 100 parts by weight of the PPS resin, the amount of plasticizer added is 2 to 5 parts by weight, the amount of organic nucleating agent added is 0.2 to 0.8 parts by weight, and the amount of polyamide resin (PA6) added is 5 to 15 parts by weight.

[0016] The plasticizer is either triphenyl phosphate (TPP) or dioctyl phthalate (DOP). The plasticizer effectively reduces the viscosity of the PPS melt, improves its fluidity, and stabilizes the subsequent spinning process, thereby reducing fiber breakage and fuzzing, and ultimately improving spinning efficiency and yarn quality. The amount of plasticizer added must be strictly controlled between 2 and 5 parts. Excessive addition (greater than 5 parts) will significantly reduce the heat resistance and strength of the PPS fiber. Insufficient addition (less than 2 parts) will not effectively exert its plasticizing effect, and the reduction in PPS melt viscosity will be insignificant, failing to significantly improve melt fluidity and spinning stability. Therefore, the addition range of 2 to 5 parts is crucial for achieving a balance between improving processing performance and maintaining excellent heat resistance and mechanical properties of the fiber.

[0017] The organic nucleating agent is one of sorbitol-based organic nucleating agents and sodium benzoate. When the organic nucleating agent is a sorbitol-based organic nucleating agent, dibenzyl sorbitol (DBS) is preferred. The function of the above-mentioned organic nucleating agent (DBS / sodium benzoate) is to provide more nucleation sites for PPS crystallization, shorten the PPS crystallization time, form finer and more uniform grains, thereby refining the crystal size of PPS, improving crystallization uniformity, reducing internal fiber defects, and significantly improving fiber toughness (elongation at break) and strength. Furthermore, the amount of organic nucleating agent added must be strictly controlled between 0.2 and 0.8 parts. If the amount added is too high (…),… Adding more than 0.8 parts not only leads to excessively dense nucleation sites, resulting in insufficient crystal growth space and affecting crystal perfection, negatively impacting the mechanical properties of PPS fibers, but also adversely affects the rheological properties of the melt. Adding too little (less than 0.2 parts) results in insufficient nucleation site density, making it difficult to effectively refine the PPS crystal structure and fully utilize its role in inducing heterogeneous nucleation and inhibiting the formation of large spherulites. This limits its effect on improving fiber toughness and strength, failing to achieve the intended effect of this invention. Therefore, the addition range of 0.2 to 0.8 parts is the optimal choice for effectively refining PPS crystals and thus synergistically improving fiber strength and toughness.

[0018] The role of the polyamide resin (PA6) mentioned above is as follows: PA6 is an engineering plastic with excellent toughness, and its introduction can effectively improve the toughness (elongation at break) of PPS fibers; and the amount of polyamide resin (PA6) added needs to be strictly controlled between 5 and 15 parts; if the amount added is too small (less than 5 parts), the PA6 phase will not be sufficiently dispersed in the PPS matrix, and an effective toughening network structure cannot be formed, resulting in a negligible improvement in the toughness of PPS fibers, making it difficult to achieve the synergistic toughening effect aimed at achieving this invention; if the amount added is too large (more than 15 parts), it will damage the inherent excellent heat resistance and chemical stability of PPS fibers, and lead to a significant decrease in the tensile strength of PPS fibers; therefore, the addition range of 5 to 15 parts is the optimal balance range for achieving effective toughening of PA6 without compromising the core performance of PPS fibers.

[0019] (2) Melt blending and granulation: The mixture obtained in step (1) is melt blended, extruded, cooled and granulated by a twin-screw extruder to obtain modified PPS masterbatch; The twin-screw extruder is divided into five temperature zones along the material conveying direction: feeding zone 260-270℃, melting zone 270-280℃, mixing zone 280-285℃, homogenizing zone 275-280℃, and die head zone 265-275℃; the screw speed is 200-300 rpm.

[0020] (3) Melt spinning: After vacuum drying, the modified PPS masterbatch obtained in step (2) is fed into a screw extruder for melt extrusion to obtain modified PPS melt. The extrusion temperature is controlled at 265-275℃ and the melt pressure is 10-20MPa. The modified PPS melt is then precisely metered by a metering pump and extruded through a spinneret to form nascent fibers.

[0021] like Figure 1 As shown, the spinneret 1 typically consists of a spinneret guide hole 2 and a spinneret micro-hole 3. The cross-sectional shape of both the spinneret guide hole 2 and the spinneret micro-hole 3 of the spinneret 1 is circular. The purpose of the circular cross-section design is to ensure that the modified PPS melt is subjected to uniform force during the extrusion process, avoid dead zones in the flow, ensure the uniformity and stability of the nascent fiber structure, and thus improve the stability of the nascent fiber in the subsequent drawing process.

[0022] The spinneret micro-orifice 3 has an aperture of 0.33–0.35 mm. This aperture range is set to precisely match the melt viscosity characteristics of the modified PPS with the final fiber fineness target. Its core function is to reduce the spinning breakage rate and ensure that the initial fiber thickness is suitable for subsequent drawing processes. Specific details are as follows: a) Reduce melt flow resistance and decrease filament breakage: If the aperture is too small (less than 0.33 mm), the melt flow resistance in the channel will increase sharply, which will easily lead to unstable melt supply and thus directly cause frequent filament breakage during spinning, making it impossible for the production line to operate continuously and stably, and greatly reducing spinning efficiency and finished product; if the aperture is too large (greater than 0.35 mm), the diameter of the nascent fiber will be too coarse, requiring a higher draw ratio to achieve the target fineness. However, the total draw ratio of this invention is only 4.0 to 5.5 times. This draw ratio is matched with the 0.33 to 0.35 mm spinneret micro-orifice diameter to ensure that the nascent fiber, after subsequent draw, yields PPS fiber with a fiber fineness that meets the requirements of high-temperature filter yarn. b) Adapting melt pressure parameters to ensure melt flowability: The melt pressure of melt spinning in this invention is set to 10-20 MPa. The spinneret micro-orifice diameter of 0.33-0.35 mm is matched with this pressure range, which can ensure smooth and stable flow of PPS melt under a pressure of 10-20 MPa, uniform filament formation, and prevent unstable melt flow, dripping, and other phenomena, thereby further reducing the filament breakage rate.

[0023] Among them, the aspect ratio of the spinneret micro-orifice 3 is (3~4):1; such as Figure 2As shown, the length of the spinneret micro-orifice 3 is H, and the diameter of the spinneret micro-orifice 3 is D. This aspect ratio design can achieve the best balance between ensuring sufficient homogenization of the melt and avoiding excessive resistance, extending the residence time of the melt in the spinneret micro-orifice 3, and ensuring stable extrusion. If the aspect ratio is too small (less than 3:1), the residence time of the melt in the spinneret micro-orifice 3 will be too short, which will lead to insufficient shearing action on the melt, which is not conducive to further homogenization of the melt and elimination of flow marks, resulting in poor uniformity of the nascent fiber structure, significantly increasing the occurrence rate of "breakage" and "fuzz" in the spinning process, making it impossible to carry out stable production. If the aspect ratio is too large (greater than 4:1), it will lead to excessive melt flow resistance, requiring extremely high extrusion pressure, which will not only increase the equipment load and energy consumption, but may also cause unstable material discharge due to poor melt delivery, which is not conducive to the stability of the spinning process.

[0024] (4) Stretching and heat setting: The nascent fibers are subjected to two-stage stretching and heat setting treatment; wherein, the first-stage stretching ratio is 2.5 to 3.5 times, and the stretching temperature is 80 to 100℃; the second-stage stretching ratio is 1.5 to 2.0 times, and the stretching temperature is 120 to 150℃; the total stretching ratio is controlled at 4.0 to 5.5 times; the heat setting temperature is 160 to 200℃; and the heat setting time is controlled at 20 to 60 seconds. This invention employs a two-stage drawing process. This gradual two-stage drawing mode greatly improves the reliability of continuous and stable operation of the spinning production line and reduces the occurrence of yarn breakage caused by sudden high-ratio drawing. The preferred heat setting time is 30 to 60 seconds, and a gradient temperature is used during the heat setting process: 160℃→180℃→200℃, with each stage held for 10 to 20 seconds. This invention performs thorough heat setting at 160-200℃ and adopts a gradient heating mode, which can effectively relax the residual stress inside the fiber. This process stabilizes the fiber structure and optimizes the fiber's breaking elongation to 35%-45%, thereby greatly improving the fiber's flexibility and fatigue resistance.

[0025] (5) Post-processing: After curling and cutting, modified PPS short fibers are obtained.

[0026] The present invention will be further described in detail below with reference to embodiments, but the scope of protection of the present invention is not limited thereto. Example 1

[0027] A method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn includes the following steps: (1) Raw material blending: Dry PPS resin, triphenyl phosphate (TPP), dibenzyl sorbitol (DBS), and polyamide resin (PA6) are uniformly mixed in a high-speed mixer; wherein, PPS resin is 10.0 kg (i.e., 100 parts), triphenyl phosphate (TPP) is 0.2 kg (2 parts), dibenzyl sorbitol (DBS) is 0.02 kg (0.2 parts), and polyamide resin (PA6) is 0.5 kg (5 parts); The total mass of the formulation composition is approximately 10.72 kg, and the mass percentage of each component is approximately as follows: PPS resin 93.28%, triphenyl phosphate (TPP) 1.87%, dibenzyl sorbitol (DBS) 0.19%, and polyamide resin (PA6) 4.66%. (2) Melt blending and granulation: The mixture obtained in step (1) is melt blended, extruded, cooled and granulated by a twin-screw extruder to obtain modified PPS masterbatch; The twin-screw extruder is divided into 5 temperature zones along the material conveying direction: feeding zone 260℃, melting zone 270℃, mixing zone 280℃, homogenizing zone 275℃, and die head zone 265℃; the screw speed is 200 rpm.

[0028] (3) Melt spinning: After vacuum drying, the modified PPS masterbatch obtained in step (2) is fed into a screw extruder for melt extrusion to obtain modified PPS melt. The extrusion temperature is controlled at 265℃ and the melt pressure is 10MPa. The modified PPS melt is then precisely metered by a metering pump and extruded through a spinneret to form nascent fibers. The cross-sectional shape of the spinneret's micro-orifice is circular, the orifice diameter is 0.33mm, and the length-to-diameter ratio of the micro-orifice is 3:1. (4) Stretching and heat setting: The nascent fibers are subjected to two-stage stretching and heat setting treatment; the first-stage stretching ratio is 2.5 times and the stretching temperature is 80℃; the second-stage stretching ratio is 1.5 times and the stretching temperature is 120℃; the total stretching ratio is controlled at 4.0 times; the heat setting process adopts gradient heating, and the heat setting temperature gradient is: 160℃→180℃→200℃, each stage is held for 10 seconds; (5) Post-processing: After curling and cutting, modified PPS short fibers are obtained. Example 2

[0029] A method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn includes the following steps: (1) Raw material blending: Dry PPS resin, dioctyl phthalate (DOP), dibenzyl sorbitol (DBS), and polyamide resin (PA6) are uniformly mixed in a high-speed mixer; The composition includes 10.0 kg (100 parts) of PPS resin, 0.4 kg (4 parts) of dioctyl phthalate (DOP), 0.06 kg (0.6 parts) of dibenzyl sorbitol (DBS), and 1 kg (10 parts) of polyamide resin (PA6). The total mass of the formulation composition is approximately 11.46 kg, and the mass percentage of each component is approximately as follows: PPS resin 87.26%, dioctyl phthalate (DOP) 3.49%, dibenzyl sorbitol (DBS) 0.52%, and polyamide resin (PA6) 8.73%. (2) Melt blending and granulation: The mixture obtained in step (1) is melt blended, extruded, cooled and granulated by a twin-screw extruder to obtain modified PPS masterbatch; The twin-screw extruder is divided into 5 temperature zones along the material conveying direction: feeding zone 265℃, melting zone 275℃, mixing zone 283℃, homogenizing zone 278℃, and die head zone 270℃; the screw speed is 250 pm.

[0030] (3) Melt spinning: After vacuum drying, the modified PPS masterbatch obtained in step (2) is fed into a screw extruder for melt extrusion to obtain modified PPS melt. The extrusion temperature is controlled at 270℃ and the melt pressure is 15MPa. The modified PPS melt is then precisely metered by a metering pump and extruded through a spinneret to form nascent fibers. The cross-sectional shape of the spinneret's micro-orifice is circular, the orifice diameter is 0.34mm, and the length-to-diameter ratio of the micro-orifice is 3.5:1.

[0031] (4) Stretching and heat setting: The nascent fibers are subjected to two-stage stretching and heat setting treatment; the first-stage stretching ratio is 3 times and the stretching temperature is 90℃; the second-stage stretching ratio is 1.8 times and the stretching temperature is 135℃; the total stretching ratio is controlled at 4.8 times; the heat setting process adopts gradient heating, and the heat setting temperature gradient is: 160℃→180℃→200℃, 160℃ is held for 20 seconds, 180℃ is held for 20 seconds, and 200℃ is held for 10 seconds; (5) Post-processing: After curling and cutting, modified PPS short fibers are obtained. Example 3

[0032] A method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn includes the following steps: (1) Raw material blending: The dried PPS resin, triphenyl phosphate (TPP), sodium benzoate and polyamide resin (PA6) are uniformly mixed in a high-speed mixer; The composition includes 10.0 kg (100 parts) of PPS resin, 0.5 kg (5 parts) of triphenyl phosphate (TPP), 0.08 kg (0.8 parts) of sodium benzoate, and 1.5 kg (15 parts) of polyamide resin (PA6). The total mass of the formulation composition is approximately 12.08 kg, and the mass percentage of each component is approximately as follows: PPS resin 82.78%, triphenyl phosphate (TPP) 4.14%, sodium benzoate 0.66%, and polyamide resin (PA6) 12.42%. (2) Melt blending and granulation: The mixture obtained in step (1) is melt blended, extruded, cooled and granulated by a twin-screw extruder to obtain modified PPS masterbatch; The twin-screw extruder is divided into 5 temperature zones along the material conveying direction: feeding zone 270℃, melting zone 280℃, mixing zone 285℃, homogenizing zone 280℃, and die head zone 275℃; the screw speed is 300 rpm.

[0033] (3) Melt spinning: After vacuum drying, the modified PPS masterbatch obtained in step (2) is fed into a screw extruder for melt extrusion to obtain modified PPS melt. The extrusion temperature is controlled at 275℃ and the melt pressure is 20MPa. The modified PPS melt is then precisely metered by a metering pump and extruded through a spinneret to form nascent fibers. The cross-sectional shape of the spinneret's micro-orifice is circular, the orifice diameter is 0.35 mm, and the length-to-diameter ratio of the micro-orifice is 4:1. (4) Stretching and heat setting: The nascent fibers are subjected to two-stage stretching and heat setting treatment; the first-stage stretching ratio is 3.5 times and the stretching temperature is 100℃; the second-stage stretching ratio is 2.0 times and the stretching temperature is 150℃; the total stretching ratio is controlled at 5.5 times; during the heat setting process, a gradient temperature is adopted, and the heat setting temperature gradient is: 160℃→180℃→200℃, 160℃ is held for 20 seconds, 180℃ is held for 20 seconds, and 200℃ is held for 20 seconds; (5) Post-processing: After curling and cutting, modified PPS short fibers are obtained.

[0034] The modified PPS masterbatches obtained in Examples 1-3 of this invention will be subjected to performance tests, and the test results will be compared with those of commercially available ordinary PPS resin. The comparison results are shown in Table 1 below: Table 1:

[0035] As shown in Table 1 above, the melt flow rate of the modified PPS masterbatches prepared in Examples 1 to 3 is better than that of commercially available ordinary PPS resin, indicating that the processing performance has been improved.

[0036] The modified PPS staple fibers obtained in Examples 1-3 of this invention will be tested for performance, and the test results will be compared with those of commercially available ordinary PPS staple fibers. The comparison results are shown in Table 2 below: Table 2:

[0037] From Table 2 above, we can see that: (1) The elongation at break (40% to 45%) of Examples 1 to 3 is greater than that of ordinary PPS fibers (25% to 35%), indicating that the mechanical properties of PSS fibers are effectively improved.

[0038] (2) The limiting oxygen index and high temperature shrinkage of Examples 1 to 3 are comparable to those of ordinary PPS short fibers, indicating that the modified PPS fibers maintain the excellent flame retardancy and high temperature resistance of ordinary PPS.

[0039] The advantages of this invention are: by combining a specific blending modification formula with an optimized spinning process, the melt viscosity is effectively reduced, the stability of the spinning process is improved, the breakage and fuzzing phenomena are significantly reduced, production efficiency and yarn quality are improved, and the prepared PPS short fibers maintain excellent high temperature resistance, chemical corrosion resistance and flame retardancy while significantly improving their breaking elongation and toughness. This gives the PPS short fibers sufficient impact resistance and flexibility, making them less prone to fatigue breakage and able to adapt to complex filtration conditions requiring high temperature, high strength and high toughness.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn, characterized in that: Includes the following steps: (1) Raw material blending: The dried PPS resin, plasticizer, organic nucleating agent and polyamide resin (PA6) are uniformly mixed in a high-speed mixer; wherein, based on 100 parts by weight of the PPS resin, the amount of plasticizer added is 2 to 5 parts by weight, the amount of organic nucleating agent added is 0.2 to 0.8 parts by weight, and the amount of polyamide resin (PA6) added is 5 to 15 parts by weight. (2) Melt blending and granulation: The mixture obtained in step (1) is melt blended, extruded, cooled and granulated by a twin-screw extruder to obtain modified PPS masterbatch; (3) Melt spinning: After vacuum drying, the modified PPS masterbatch obtained in step (2) is fed into a screw extruder for melt extrusion to obtain modified PPS melt. The extrusion temperature is controlled at 265-275℃ and the melt pressure is 10-20MPa. The modified PPS melt is then precisely metered by a metering pump and extruded through a spinneret to form nascent fibers. (4) Stretching and heat setting: The nascent fibers are subjected to two-stage stretching and heat setting treatment; wherein, the first-stage stretching ratio is 2.5 to 3.5 times, and the stretching temperature is 80 to 100℃; the second-stage stretching ratio is 1.5 to 2.0 times, and the stretching temperature is 120 to 150℃; the total stretching ratio is controlled at 4.0 to 5.5 times; the heat setting temperature is 160 to 200℃; and the heat setting time is controlled at 20 to 60 seconds. (5) Post-processing: After curling and cutting, modified PPS short fibers are obtained.

2. The method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn according to claim 1, characterized in that: The plasticizer is one of triphenyl phosphate (TPP) and dioctyl phthalate (DOP).

3. The method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn according to claim 1, characterized in that: The organic nucleating agent is one of the sorbitol-based organic nucleating agents and sodium benzoate.

4. The method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn according to claim 3, characterized in that: Dibenzyl sorbitol (DBS) is selected as the organic nucleating agent for sorbitol derivatives.

5. The method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn according to claim 1, characterized in that: In step (2), the twin-screw extruder is divided into 5 temperature zones along the material conveying direction: feeding zone 260-270℃, melting zone 270-280℃, mixing zone 280-285℃, homogenizing zone 275-280℃, and die head zone 265-275℃; the screw speed is 200-300 rpm.

6. The method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn according to claim 1, characterized in that: In step (3), the cross-sectional shape of the spinneret micro-orifice is circular, the diameter of the spinneret micro-orifice is 0.33-0.35 mm, and the length-to-diameter ratio of the spinneret micro-orifice is (3-4):

1.

7. The method for modifying and preparing PPS short fibers for high-performance high-temperature filter yarn according to claim 1, characterized in that: In step (4), a gradient temperature is used during the heat setting process: 160℃→180℃→200℃, with each stage held for 10 to 20 seconds.

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