Organic-inorganic hybrid wave-absorbing polyester filament and preparation method thereof

Abstract

This invention relates to the field of chemical fiber technology, and discloses an organic-inorganic hybrid microwave-absorbing polyester filament and its preparation method. The preparation method of the microwave-absorbing polyester filament includes the following steps: grinding nano-silver powder, superconducting graphite, ceramic microspheres, coupling agent, dispersant, and matrix material, controlling the rotation speed to prepare a conductive masterbatch; then drying polyester chips and melt-spinning them with the conductive masterbatch to obtain the microwave-absorbing polyester filament; wherein the components of the conductive masterbatch, by mass percentage, include: matrix material 50-90%, nano-silver powder 1%-20%, superconducting graphite 1-30%, ceramic microspheres 1-5%, coupling agent 0.3-5%, and dispersant 1-10%. The microwave-absorbing fiber prepared by the above method simultaneously possesses the characteristics of being lightweight, mildew-resistant, having high tensile strength, high high-frequency absorption intensity, and broadband microwave absorption, and is widely used in the preparation of camouflage nets, decoys, military tents, and equipment camouflage tarpaulins.

Description

Technical Field

[0001] This invention relates to the field of chemical fiber technology, and in particular to an organic-inorganic hybrid microwave-absorbing polyester filament and its preparation method. Background Technology

[0002] Polyester fiber, commonly known as polyester fiber, is obtained by spinning polyester, which is formed by the condensation of organic diacids and diols. It is also known as PET fiber. Polyester fiber has good wrinkle resistance, high strength, and is durable, making it the largest variety of synthetic fiber.

[0003] Wave-absorbing polyester filaments can be woven into wave-absorbing fabric, which can then be processed into military camouflage nets, camouflage tents, decoys, camouflage tarpaulins, and other products. This type of camouflage base fabric represents a novel structural form, integrating the base material and wave-absorbing agent into one unit. Currently, most commonly used camouflage base fabrics employ a coating structure, applying one or more layers of wave-absorbing coating to conventional fiber fabric. Most camouflage fabrics currently on the market utilize this coating method. For example, a certain ultralight camouflage fabric from the United States has a mass of 216 g / m³. 2 This camouflage fabric, made of sparse polyester fabric and a coating, is used for camouflage of attack helicopters. The camouflage fabric of the Teledyen In C lightweight camouflage and obscuring system, manufactured in the United States, is a fabric woven from a blend of polyester and stainless steel fibers, joined together with nylon webbing featuring small hooks. A US patent discloses an infrared camouflage fabric coated with a flame-retardant material having a porous structure, with a supporting material being a polyester fabric incorporating metal fibers. A Japanese patent discloses a camouflage fabric with a polyester fiber base material, including fibrous metal sheets, plastic sheets, and a camouflage coating, which is convenient and effective to use. The RABSORBCND camouflage fabric produced in Hungary is made of polyester bulky yarn coated with a coating, with varying mesh sizes; this camouflage fabric has radar-absorbing properties. The FMS Army camouflage fabric produced in Israel is made of 100% polyester yarn with four layers of coating.

[0004] The main domestic and international technologies for polyester filament include the one-step spinning and drawing process (FDY process), the two-step UDY-DT process, and the two-step POY-DT process. The FDY process uses high-viscosity polyester chips and requires a slow cooling device during the spinning process, resulting in high manufacturing costs, especially when producing fine denier filaments below 150D. The UDY-DT two-step process first spins undrawn yarn and then performs multiple stages of high-ratio drawing, but the resulting polyester filaments have low strength, lack effective setting, and have a high heat shrinkage rate, and have been largely phased out. Patent CN101086086B uses the POY-DT two-step process, sequentially performing primary drawing, tension heat setting, secondary drawing, relaxation heat setting, and winding to produce fine denier, high-strength, low-shrinkage, and low-elongation polyester filaments. The strength and boiling water shrinkage rate of the obtained polyester filaments can meet the requirements of medium-to-high-grade filament sewing threads. However, its process is lengthy, energy-intensive, and has a high breakage rate during production, resulting in high production costs. Patent CN112680814 A uses FDY one-step melting spinning, low-speed spinning, two-stage high-ratio drawing, tension heat setting, and other process conditions such as drawing temperature, speed, drawing ratio and their distribution relationship, and setting temperature. However, this patent uses this method to prepare an antistatic polyester filament, and fibers with wave absorption properties have not been applied.

[0005] Therefore, there is an urgent need for a microwave-absorbing polyester filament and its preparation method to solve the above problems. Summary of the Invention

[0006] Based on the above, the purpose of this invention is to provide an organic-inorganic hybrid microwave-absorbing polyester filament and its preparation method, so that the microwave-absorbing fiber simultaneously possesses the characteristics of being lightweight, mildew-resistant, having high tensile strength, high microwave absorption intensity in the high-frequency band, and having broadband microwave absorption.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament includes the following steps:

[0009] S1. Nano-silver powder, superconducting graphite, ceramic microspheres, coupling agent, dispersant and matrix material are ground and the rotation speed is controlled to prepare conductive masterbatch;

[0010] S2. The polyester chips are dried and then melt-spun with the conductive masterbatch to obtain microwave-absorbing polyester filament.

[0011] In step S1, the components of the conductive masterbatch include, by mass percentage:

[0012]

[0013] In a preferred embodiment of a method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament, the rotation speed in step S1 is 2000–4000 r / min.

[0014] In a preferred embodiment of a method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament, in step S1, the matrix material is a polyester with a viscosity of 1.0 to 1.15 dL / g.

[0015] In a preferred embodiment of a method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament, the nano-silver powder in step S1 has a particle size of 10–50 nm.

[0016] In a preferred embodiment of a method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament, the superconducting graphite in step S1 has an electrical conductivity of 100–300 S / cm.

[0017] In a preferred embodiment of a method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament, the ceramic microspheres in step S1 have a particle size of 3–5 nm.

[0018] In a preferred embodiment of a method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament, in step S1, the dispersant comprises a sulfonic acid- and carboxyl-modified multihydroxy block zigzag polymer; and the coupling agent comprises a siloxane coupling agent.

[0019] In a preferred embodiment of a method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament, in step S2, the conductive masterbatch accounts for 5-30% of the polyester content; and the viscosity of the polyester chips is 0.64-0.65 dL / g.

[0020] As a preferred embodiment of the preparation method of organic-inorganic hybrid microwave-absorbing polyester filament, in step S2, the melt spinning process adopts a method of low-speed spinning, two-stage high-ratio drawing, and tension heat setting; wherein in the two-stage high-ratio drawing process, the first hot roller and the second hot roller are each equipped with a roller, and the third hot roller and the fourth hot roller are used in pairs.

[0021] An organic-inorganic hybrid microwave-absorbing polyester filament is prepared by the above-described method.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention provides an organic-inorganic hybrid microwave-absorbing polyester filament and its preparation method. The polyester filament is first prepared by using nano-silver powder, superconducting graphite, ceramic microspheres, coupling agent, dispersant and matrix material in a certain ratio to prepare a conductive masterbatch. Then, the conductive masterbatch is blended and melt-spun with ordinary viscosity polyester chips that have been dried. The spinning process includes low-speed spinning, multi-stage high-ratio drawing and tension heat setting. The process conditions such as drawing temperature, speed, drawing ratio and their distribution relationship and setting temperature are properly handled. Finally, a special microwave-absorbing polyester filament with lightweight, mildew resistance, high tensile strength, high high-frequency microwave absorption intensity and wide-band microwave absorption characteristics is prepared.

[0024] First, this invention uses polyester chips of conventional viscosity (0.64-0.65 dL / g) to replace high-viscosity chips (1.0-1.15 dL / g) through a drying and thickening process for melt spinning, preparing high-strength, low-heat-shrinkage wavelength-absorbing fibers. By controlling the multiple stretching and winding speed, the fibers achieve regular molecular arrangement and crystal structure during stretching, improving the strength of the wavelength-absorbing fibers and solving the mechanical strength problem. The coupling agent and dispersant utilize their -OH, -COO-, -SO3 bonds, with one end attached to the conductive filler and the other end attached to the organic polyester PET, forming a stable state that allows the conductive powder to be evenly distributed in the fiber.

[0025] Secondly, ceramic microspheres act as lubricants for the nano-silver powder and superconducting graphite in the microwave-absorbing fibers. After the filament bundle is ejected from the spinneret, before it cools, the nano-silver powder and superconducting graphite slide within the PET, arranging themselves along the drawing direction for better uniform mixing and orientation, thus improving the electromagnetic wave attenuation performance. During the stretching process, friction between the filaments and the hot rollers is reduced, significantly decreasing filament breakage and reinforcing the fibers. The silver powder in the microwave-absorbing fibers also provides anti-mildew protection, reducing the need for an anti-mildew coating and lowering the fabric's surface density. The surface density of the woven microwave-absorbing fabric is only 153 g / m². 2 Coated absorber fabric typically has a surface density of 300 g / m². 2 Compared to coated fabric, its surface density is significantly lower, while its surface density is significantly higher. This fiber can be woven into fabric and then used to prepare camouflage nets, decoys, military tents, equipment camouflage tarpaulins, and many other applications.

[0026] Finally, this invention uses nano-silver powder and superconducting graphite as conductive agents. Through formulation design, the impedance of the fiber surface is matched with that of radar waves. The radar wave attenuation of the woven absorbing fabric is as follows: average attenuation value ≥3.8dB in L and S bands, average attenuation value ≥8.5dB in C and X bands, and average attenuation value ≥18dB in Ku, K, and Ka bands. Its radar absorption performance is significantly better than that of conventional coated fabrics. Detailed Implementation

[0027] To facilitate understanding of the present invention, a more comprehensive description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention. Unless otherwise defined, all technical and scientific terms used in this invention pertain to the technical field of the invention.

[0028] This embodiment provides an organic-inorganic hybrid microwave-absorbing polyester filament and its preparation method. The polyester filament is first prepared by grinding and mixing nano-silver powder, superconducting graphite, ceramic microspheres, coupling agent, dispersant and matrix material, controlling the rotation speed to 2000-4000 r / min to ensure uniform mixing, and preparing a conductive masterbatch. Then, the conductive masterbatch is blended and melt-spun with ordinary viscosity polyester chips that have been dried. The spinning process includes low-speed spinning, multi-stage high-ratio drawing, and tension heat setting. The process conditions such as drawing temperature, speed, drawing ratio and their distribution relationship and setting temperature are properly handled. Finally, a special microwave-absorbing polyester filament with lightweight, mildew resistance, high tensile strength, high high-frequency microwave absorption intensity and wide-band absorption characteristics is prepared.

[0029] Specifically, the components of the conductive masterbatch, by mass percentage, include: 50-90% matrix material, 1%-20% nano silver powder, 1-30% superconducting graphite, 1-5% ceramic microspheres, 0.3-5% coupling agent, and 1-10% dispersant.

[0030] Furthermore, the conductive masterbatch contains 10-50 nm silver nanoparticles with a silver coin-shaped structure, and the superconducting graphite has a conductivity of 100-300 S / cm. Using these two components as conductive agents, the formula is designed to match the impedance of the fiber surface with radar waves. The dielectric properties of the conductive filler reduce radar wave attenuation. The woven radar-absorbing fabric exhibits the following radar wave attenuation: average attenuation value ≥3.8 dB in L and S bands, average attenuation value ≥8.5 dB in C and X bands, and average attenuation value ≥18 dB in Ku, K, and Ka bands, demonstrating excellent radar absorption performance. This silver powder also provides anti-mildew properties, reducing the need for an anti-mildew coating layer and lowering the fiber's areal density.

[0031] Furthermore, the ceramic microspheres are 3-5 nm spherical solid beads that act as lubricants for nano-silver powder and superconducting graphite in the microwave absorbing fibers. After the filament bundle is ejected from the spinneret, before the bundle cools down, the nano-silver powder and superconducting graphite can slide in the PET and be arranged along the drawing direction, which can better achieve uniform mixing and orientation, and improve the loss performance of electromagnetic waves. During the stretching process, the friction between the filament and the hot roller is reduced, which greatly reduces filament breakage and also strengthens the fibers.

[0032] Furthermore, the dispersant includes sulfonic acid- and carboxyl-modified polyhydroxy block zigzag polymers, and the coupling agent includes siloxane coupling agents. The coupling agent and dispersant can utilize their -OH, -COO-, -SO3, and other bonds to bond one end to the conductive filler and the other end to the organic polyester PET, forming a stable state, so that the conductive powder can be evenly distributed in the fiber.

[0033] Furthermore, the matrix material is PET polyester with a viscosity of 1.0 to 1.15 dL / g.

[0034] Furthermore, when the conductive masterbatch is blended and melt-spun with ordinary viscosity polyester chips that have been dried, the conductive masterbatch accounts for 5% to 30% of the polyester content, and the viscosity of the polyester chips is 0.64 to 0.65 dL / g. This process is mainly to dilute the silver powder, graphite and other components in the conductive masterbatch so that the spinning process is not easy to break.

[0035] Specifically, polyester chips need to undergo a drying process. Wet chips of ordinary viscosity are transported to a high-level tank via a pulse system, and then from the high-level tank to a pre-crystallizer and main drying tower for drying and thickening, ensuring the moisture content of the dry chips is ≤20ppm. The dried chips are then transported to a dry chip storage tank. Conventional viscosity polyester chips are used to replace high-viscosity chips for melt spinning through drying and thickening, producing high-strength, low-heat-shrinkage wavelength-absorbing fibers. By controlling multiple stretching and winding speeds, the fibers achieve regular molecular arrangement and crystal structure during stretching, improving the strength of the wavelength-absorbing fibers and solving the mechanical strength problem. Furthermore, conventional viscosity polyester chips are less expensive and the spinning process is more convenient.

[0036] Further, the spinning process mainly includes: the conductive masterbatch is mixed with dry polyester chips and then fed into a single-screw extruder for melt extrusion. The melt then enters a filter, spinning box, metering pump, and spinneret. The filaments extruded from the spinneret are virgin filaments. These virgin filaments then undergo secondary drafting and tension heat setting through a series of processes including "side-blown cooling → spinning duct → oiling roller → pre-networker → first hot roller → second hot roller → third and fourth hot rollers → main networker → winding". Controlling the moisture and heat and oxidative degradation during the spinning process, controlling the temperature and melt uniformity in each zone, and properly managing the side-blown air and spinning speed are crucial. The drafting process has a significant impact on the orientation and crystallization of the filaments, requiring careful management of the drafting temperature, speed, drafting ratio, and their distribution.

[0037] Specifically, the main technical parameters are as follows: pre-crystallizer temperature: 168–171℃; residence time in the pre-crystallizer: 17–20 min; main drying temperature: 168–170℃; residence time in the main drying tower: 6 h; temperature distribution of each zone of the screw extruder: Zone 1: 263–268℃, Zone 2: 268–272℃, Zone 3: 272–275℃, Zone 4: 275–278℃, Zone 5: 278–281℃, Zone 6: 278–281℃; die head temperature: 281–283℃; spinning box temperature: 278–281℃; die head pressure: 15 MPa; melt filter outlet pressure: 15 MPa. 11.5~13MPa; the metal grit in the component is composed of one or more combinations of 20~30 mesh, 40~60 mesh, and 60~80 mesh; pre-network pressure: 0.13MPa, main network pressure: 0.32MPa, oil application: 0.9~1.5%, side blowing air temperature: 22℃, air velocity: 0.4~0.55m / s, first hot roller temperature: 110℃, speed: 550~650m / s, second hot roller temperature: 120℃, speed: 2300~2350m / s, third hot roller temperature: 240℃, speed: 3300~3800m / s, winding speed: 3300~3350m / s.

[0038] More specifically, the oiling method adopts the oiling wheel oiling method, the oil concentration is 9-11%, and the oiling amount is 0.8-1.5%. A pair of guide rollers are added below the oil wheel and above the pre-networker. The purpose of adding guide rollers is to prevent the yarn from shaking and causing the yarn to collide with each other on the first hot roller, thereby reducing the breakage rate.

[0039] Furthermore, in the secondary drafting mechanism, the first and second hot rollers are each equipped with a roller, while the third and fourth hot rollers are used in pairs. This differs from the three-pair hot roller production method commonly used in polyester industrial yarn production, thus reducing energy consumption. The third-stage hot roller adopts a double-roller configuration, primarily to reduce boiling water shrinkage. The addition of conductive masterbatch in the microwave-absorbing fiber can easily cause crystallization of the internal orientation molecular chain segments. Therefore, adding a hot roller reduces this situation and prevents breakage. The filament is wound 8 times on the first hot roller, 5 times on the second hot roller, and 8 times on the third hot roller. The first and second hot rollers are chrome-plated with a low coefficient of friction, while the third and fourth hot rollers are enamel-plated with a high coefficient of friction. Through multiple stretching and controlled winding speeds, the fibers achieve regular molecular arrangement and crystal structure during the stretching process, improving the strength and microwave absorption performance of the microwave-absorbing fiber.

[0040] The invention will be further illustrated below with specific embodiments.

[0041] Example 1

[0042] Preparation of conductive masterbatch:

[0043] The components of the conductive masterbatch, by mass percentage, include: 9% nano silver powder, 13% superconducting graphite, 3% ceramic microspheres, 5% coupling agent, 5% dispersant, and 65% matrix material.

[0044] Nano-silver powder, superconducting graphite, ceramic microspheres, coupling agent, and dispersant were mixed and ground in a ball mill at a controlled rotation speed of 3500 r / min to ensure uniform mixing. The uniformly ground conductive slurry was then precisely metered with high-viscosity PET chips (1.15 dL / g) using a metering valve and fed into the feed inlet of a twin-screw extruder through two conical tanks. The extruder was then used for granulation.

[0045] Preparation of microwave absorbing fibers:

[0046] Wet polyester PET chips with a viscosity of 0.65 dL / g are used. Powder and large particles are removed by a vibrating screen. The chips are then conveyed to a high-level feed tank by a pulse device. The chips then enter the pre-crystallizer from the high-level feed tank. They stay in the pre-crystallizer for 18 minutes at a drying temperature of 169°C. They then stay in the main drying tower for 6 hours at a drying temperature of 168°C. The final moisture content of the chips is ≤20 ppm.

[0047] The conductive masterbatch was metered using a metering valve and then fed simultaneously with dried PET chips into a single-screw extruder for melt extrusion. The conductive masterbatch accounted for 11% of the mass, and the dried PET chips accounted for 89% of the mass. The temperatures of each zone of the screw were as follows: Zone 1: 265℃, Zone 2: 268℃, Zone 3: 272℃, Zone 4: 276℃, Zone 5: 280℃, Zone 6: 281℃, Die head temperature: 283℃, and Spinning box temperature: 281℃.

[0048] After passing through the screw extruder, the melt enters the melt filter, then the static mixer, and finally the spinning box. It is then distributed to various metering pumps, which meter it before it enters the spinning assembly.

[0049] After exiting the spinneret, the filaments enter the spinning window for cooling. The side-blowing air velocity is set to 0.45 m / s, the temperature to 23℃, and the humidity to 75%. The fibers are oiled using an oiling wheel with an oil concentration of 10% and an oiling amount set to 1.0%. Then, a pre-networking process is performed to ensure the oil is more evenly distributed on the filament surface. The pre-networking pressure is set to 0.13 MPa. After passing through the pre-network, the filaments enter the drafting hot rollers. This practical application uses a low-speed spinning and high-ratio drafting method. The first hot roller speed is set to 550 m / s, the temperature to 110℃, and 8 windings; the second hot roller speed is set to 2306 m / s, the temperature to 120℃, and 5 windings; the third and fourth hot roller speeds are set to 3130 m / s, the temperature to 238℃, and 8 windings. After being shaped by the third hot roller, the filament enters the main network device for twisting to improve its strength. The main network pressure is 0.3 MPa. After passing through the main network, the filament enters the winding mechanism, with a winding speed of 3105 m / s, ultimately yielding microwave-absorbing fibers.

[0050] Example 2

[0051] Preparation of conductive masterbatch:

[0052] The components of the conductive masterbatch, by mass percentage, include: 1% nano silver powder, 1% superconducting graphite, 1% ceramic microspheres, 0.3% coupling agent, 6.7% dispersant, and 90% matrix material.

[0053] Nano-silver powder, superconducting graphite, ceramic microspheres, coupling agent, and dispersant were mixed and ground in a ball mill at a controlled rotation speed of 2000 r / min to ensure uniform mixing. The uniformly ground conductive slurry was then precisely metered with high-viscosity PET chips (1.0 dL / g) using a metering valve and fed into the feed inlet of a twin-screw extruder through two conical tanks. The extruder was then used for granulation.

[0054] Preparation of microwave absorbing fibers:

[0055] Based on the above, the conductive masterbatch has a mass percentage of 30%, the dried PET chips have a mass percentage of 70%, and other preparation processes are consistent with those in Example 1, ultimately yielding microwave absorbing fibers.

[0056] Example 3

[0057] Preparation of conductive masterbatch:

[0058] The components of the conductive masterbatch, by mass percentage, include: 20% nano silver powder, 20% superconducting graphite, 5% ceramic microspheres, 4% coupling agent, 1% dispersant, and 50% matrix material.

[0059] Nano-silver powder, superconducting graphite, ceramic microspheres, coupling agent, and dispersant were mixed and ground in a ball mill at a controlled rotation speed of 4000 r / min to ensure uniform mixing. The uniformly ground conductive slurry was then precisely metered with high-viscosity PET chips (1.1 dL / g) using a metering valve and fed into the feed inlet of a twin-screw extruder through two conical tanks. The extruder was then used for granulation.

[0060] Preparation of microwave absorbing fibers:

[0061] Based on the above, the conductive masterbatch has a mass percentage of 20%, the dried PET chips have a mass percentage of 80%, and other preparation processes are consistent with those in Example 1, ultimately yielding microwave absorbing fibers.

[0062] Example 4

[0063] Preparation of conductive masterbatch:

[0064] The components of the conductive masterbatch, by mass percentage, include: 8% nano silver powder, 30% superconducting graphite, 1% ceramic microspheres, 1% coupling agent, 10% dispersant, and 50% matrix material.

[0065] Nano-silver powder, superconducting graphite, ceramic microspheres, coupling agent, and dispersant were mixed and ground in a ball mill at a controlled rotation speed of 3500 r / min to ensure uniform mixing. The uniformly ground conductive slurry was then precisely metered with high-viscosity PET chips (1.1 dL / g) using a metering valve and fed into the feed inlet of a twin-screw extruder through two conical tanks. The extruder was then used for granulation.

[0066] Preparation of microwave absorbing fibers:

[0067] Based on the above, the conductive masterbatch has a mass percentage of 5%, the dried PET chips have a mass percentage of 95%, and other preparation processes are consistent with those in Example 1, ultimately yielding microwave absorbing fibers.

[0068] To further illustrate the key aspects of this patent, comparative examples are provided.

[0069] The microwave-absorbing fibers obtained after spinning in this application are woven into fabric to obtain microwave-absorbing cloth. A comparison of the performance tests of Snark coated cloth and Xinhua coated cloth is shown in Table 1.

[0070] Table 1 Comparison of Key Performance Indicators

[0071]

[0072]

[0073] As can be seen from the table above, the microwave absorbing fiber produced in this application can simultaneously possess the characteristics of being lightweight, mildew resistant, having high tensile strength, high high-frequency absorption intensity, and having broadband absorption properties. It can be widely used in the preparation of camouflage nets, decoys, military tents, equipment camouflage tarpaulins, and many other applications.

[0074] The above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for preparing an organic-inorganic hybrid microwave-absorbing polyester filament, characterized in that, Includes the following steps: S1. Nano-silver powder, superconducting graphite, nano-ceramic materials, coupling agent, dispersant and matrix material are ground and the rotation speed is controlled to prepare conductive masterbatch; The particle size of the nano-ceramic material is 3~5nm; S2. The polyester chips are dried and then melt-spun with the conductive masterbatch to obtain microwave-absorbing polyester filament. In step S1, the components of the conductive masterbatch, by mass percentage, include: Matrix material 50~90% Nano silver powder 1% ~ 20% Superconducting graphite 1~30% Nano-ceramic materials 1~5% Coupling agent 0.3~5% Dispersant 1~10%.

2. The method for preparing organic-inorganic hybrid microwave-absorbing polyester filament according to claim 1, characterized in that, In step S1, the rotation speed is 2000~4000 r / min.

3. The method for preparing organic-inorganic hybrid microwave-absorbing polyester filament according to claim 1, characterized in that, In step S1, the matrix material is a polyester with a viscosity of 1.0~1.15 dL / g.

4. The method for preparing organic-inorganic hybrid microwave-absorbing polyester filament according to claim 1, characterized in that, In step S1, the particle size of the nano-silver powder is 10~50nm.

5. The method for preparing organic-inorganic hybrid microwave-absorbing polyester filament according to claim 1, characterized in that, In S1, the electrical conductivity of the superconducting graphite is 100~300 S / cm.

6. The method for preparing organic-inorganic hybrid microwave-absorbing polyester filament according to claim 1, characterized in that, In S1, the dispersant includes a sulfonic acid- and carboxyl-modified multihydroxy block zigzag polymer; the coupling agent includes a siloxane coupling agent.

7. The method for preparing organic-inorganic hybrid microwave-absorbing polyester filament according to claim 1, characterized in that, In step S2, the conductive masterbatch accounts for 5-30% of the polyester content; the viscosity of the polyester chips is 0.64-0.65 dL / g.

8. The method for preparing organic-inorganic hybrid microwave-absorbing polyester filament according to claim 1, characterized in that, In S2, the melt spinning process employs a method of low-speed spinning, two-stage high-ratio drawing, and tension heat setting; wherein in the two-stage high-ratio drawing process, the first and second hot rollers are each equipped with a roller, and the third and fourth hot rollers are used in pairs.

9. An organic-inorganic hybrid microwave-absorbing polyester filament, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

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