Anti-far and anti-near infrared polyester fabric and preparation method thereof

Abstract

The invention relates to a far-infrared and near-infrared prevention polyester fabric and a preparation method thereof in the field of polyester fabric production, and the preparation method specifically comprises the following steps: melting polyester, and adding 0.01%-10% of far-infrared prevention particles; preparing the molten polyester into a spinning solution for spinning, and weaving into polyester fabric; the method comprises the following steps: washing polyester fabric with alkali for later use, dyeing the polyester fabric with two or more disperse dyes, and enabling dye liquor to circularly flow in a dyeing device through a centrifugal pump in the dyeing process during dyeing; in the circular flowing process, the quality of the circulating dye liquor of the dyeing device is detected, color fixation is conducted after dyeing, efficient and accurate far-infrared and near-infrared prevention polyester fabric preparation is achieved, through circular dyeing management, real-time dye liquor detection, the heat exchange unit, the step-by-step dyeing method and the like, the preparation efficiency is improved, and the production cost is reduced. And the reflection performance of the cloth in a specific infrared band is ensured to meet the design requirements.

Description

Technical Field

[0001] The present invention relates to a polyester fabric and a preparation method thereof, and in particular to a far- and near-infrared resistant polyester fabric used in the field of polyester fabric production and a preparation method thereof. Background Art

[0002] Existing technologies for polyester fabrics that block far- and near-infrared radiation primarily focus on developing fibers and coatings with specialized properties to enhance the fabric's ability to reflect or absorb infrared radiation. These fabrics typically achieve this by doping polyester fibers with specific metal oxides, carbon-based materials, or other infrared reflectors. For example, the addition of materials such as tin oxide or zinc oxide can enhance the fabric's infrared reflection properties, thereby achieving infrared protection. Additionally, some fabrics utilize surface coating or lamination techniques with infrared-absorbing nanomaterials or specialized coatings to reduce infrared radiation transmittance.

[0003] These technologies not only improve the infrared protection performance of the fabric, but also maintain the original advantages of polyester fabric, such as lightness, durability and easy cleaning. In the fields of military, security and privacy protection, this kind of polyester fabric with far and near infrared protection has broad application prospects.

[0004] The specification of Chinese invention patent CN103290703B discloses a processing technology for polyester anti-infrared camouflage printed webbing, which uses polyester as raw material and achieves the purpose of infrared protection through processes such as dyeing, printing and baking. The processing method of this processing technology ensures that both product quality and functionality are achieved. The polyester material cost is lower, which reduces the cost for users, making it easier for users to accept and more conducive to the company's market development and long-term development.

[0005] The specification of Chinese invention patent CN106049092B discloses an infrared-proof military camouflage fabric and its printing and dyeing process. The warp and weft yarns of the camouflage fabric are both made of cotton-polyester blended yarns, which are blended from cotton fiber, polyester fiber, nylon fiber and silk fiber. The dyeing process adopts disperse bath dyeing with vat dyes and disperse dyes; the printing process adopts the same slurry printing with vat dyes and disperse dyes. The infrared-proof military camouflage fabric and its printing and dyeing process of the invention have the advantages of good infrared-proof camouflage performance, high color fastness, rich color and low cost.

[0006] Existing technologies mainly improve the fabric's ability to reflect or absorb infrared rays by doping with specific metal oxides, carbon-based materials or other infrared reflectors, but they do not achieve the ideal reflectivity in the infrared band. In addition, the dyeing process may have problems such as unstable dye concentration and difficult to detect dye contamination, which affects the quality of the final fabric. Summary of the Invention

[0007] In response to the above-mentioned existing technologies, the technical problem to be solved by the present invention is that the existing technologies mainly improve the fabric's ability to reflect or absorb infrared rays by doping with specific metal oxides, carbon-based materials or other infrared reflectors, but fail to achieve the ideal infrared band reflectivity. In addition, the dyeing process may have problems such as unstable dye concentration and difficult detection of dye contamination, which affects the quality of the final fabric.

[0008] To solve the above problems, the present invention provides a method for preparing a far- and near-infrared resistant polyester fabric, which specifically comprises the following steps:

[0009] S1, melting the polyester and adding 0.01%-10% of far-infrared shielding particles;

[0010] S2, preparing the molten polyester into a spinning solution for spinning, and then weaving the molten polyester using an air jet loom to obtain a polyester fabric;

[0011] S3, the polyester cloth is cleaned and set aside, the alkali washing conditions are 0.4g / L-2g / L soda ash, and the alkali washing temperature is 80℃;

[0012] S4, dye solution preparation, selecting two or more disperse dyes to dye the polyester fabric, the disperse dyes matching the 700nm-1300nm infrared reflectivity curve, and the reflectivity is 10%-70%;

[0013] S5, prepare for dyeing, dissolve disperse dye in organic solvent at a total concentration of 0.5%-6%, add environmentally friendly carrier, leveling agent and pH adjuster;

[0014] S6, dyeing, heating to 100-110°C at 2°C / min, keeping warm for 60 minutes, and circulating the dye solution in the dyeing device by a centrifugal pump during the dyeing process; during the circulation process, the quality of the dye solution circulating in the dyeing device is tested, and when accumulation of pollutants in the dye solution is detected, the dye solution is completely replaced; when the dye concentration is lower than the set value, new dye solution is dynamically added and an equal amount of old dye solution is discharged, and the discharged old dye solution is used to preheat the input new dye solution;

[0015] S7, color fixing, after dyeing, use hydrosulfite and caustic soda to wash at 80℃ for 15 minutes to remove floating color and improve color fastness, and finally acid wash until the fabric pH is neutral.

[0016] In the above-mentioned preparation method of far- and near-infrared resistant polyester fabric, efficient and accurate preparation of far- and near-infrared resistant polyester fabric is achieved through cyclic dyeing management, real-time dye solution detection, heat exchange unit and step-by-step dyeing method.

[0017] As a further improvement of the present application, the dyeing device includes a dyeing tank and a circulation pipe, the circulation pipe includes an upper guide tank and a lower guide pipe, the lower guide pipe is connected to a drain pipe and communicates with a centrifugal pump, and the upper guide tank is connected to a compensation pipe and communicates with the dyeing tank;

[0018] A centrifugal pump is installed between the dyeing tank and the circulation pipe, and a main output pipe and a dye liquid detection unit 4 are connected between the centrifugal pump and the dyeing tank. The dye liquid detection unit includes a shunt pipe connected to the main output pipe, and an electrochemical sensor and an optical fiber in-situ sensor are installed in the shunt pipe; the dye liquid detection unit detects the dye liquid concentration and impurity content during the dye liquid circulation process.

[0019] As a further improvement of the present application, the dye liquid detection unit includes a sampling and analysis structure, which includes a detection box arranged on the outside of the shunt tube, a branch tube connected to the shunt tube arranged in the detection box, at least two sampling tubes connected to the branch tube, and a visual detection module and a spectral detection module matching the sampling tube arranged in the detection box.

[0020] As a further improvement of the present application, a heat exchange unit is installed at the output end of the centrifugal pump, and the heat exchange unit includes a main infusion pipe for connecting the centrifugal pump and the circulation pipe. The outer side of the main infusion pipe is sleeved with an outer heat exchange shell, and a heat exchange pipe wrapped around the main infusion pipe is passed through the outer heat exchange shell. The input end of the heat exchange pipe is connected to the secondary dye liquid tank, and the output end of the heat exchange pipe is connected to the compensation pipe.

[0021] As another improvement of the present application, the secondary dye liquid tank is used to prepare the compensation dye liquid, and an agitator and a quantitative feeding device are installed in the secondary dye liquid tank.

[0022] As another improved supplement of the present application, disperse dyes include red, yellow, blue, navy, black, golden yellow and turquoise blue.

[0023] As another improved supplement of the present application, the particle size range of the far-infrared protection microparticles includes 5 nanometers to 5 microns, and the fineness range of the spun single fiber is: 0.3-1.5 deniers.

[0024] As another improvement of the present application, during S5 dyeing, a low-refractive-index dye is first used for pre-dyeing to form a base reflective layer, and then a high-refractive-index dye is superimposed for main dyeing.

[0025] A polyester fabric that is resistant to far and near infrared radiation, with a PU coating sprayed on the polyester fabric.

[0026] In summary, this solution achieves efficient and precise preparation of far- and near-infrared resistant polyester fabrics. Through cyclic dyeing management, real-time dye liquor detection, heat exchange units, and step-by-step dyeing methods, it not only improves preparation efficiency but also ensures that the fabric's reflective performance within a specific infrared band meets design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flow chart of the preparation method of the first and second embodiments of the present application;

[0028] Figure 23D diagrams of dyeing devices according to the first and second embodiments of the present application;

[0029] Figure 3 This is a dye liquor circulation path diagram of the dyeing device of the first and second embodiments of the present application;

[0030] Figure 4 This is a cross-sectional view of the heat exchange unit of the second and third embodiments of the present application;

[0031] Figure 5 This is a cross-sectional view of the dye solution detection unit according to the second and third embodiments of the present application;

[0032] Figure 6 for Figure 5 Schematic diagram of the structure at A in the middle;

[0033] Figure 7 This is a detection workflow diagram for the third implementation method of this application.

[0034] Description of the numbers in the figure:

[0035] 1. Dyeing tank; 2. Circulation pipe; 21. Upper guide tank; 22. Lower guide pipe; 3. Centrifugal pump; 4. Spectral detection module; 41. Diversion pipe; 42. Branch pipe; 43. Sampling tube; 5. Heat exchange unit; 51. Main infusion pipe; 52. External heat exchange shell; 53. Heat exchange tube. DETAILED DESCRIPTION

[0036] The following describes five implementation methods of the present application in detail with reference to the accompanying drawings.

[0037] The first implementation method:

[0038] Figures 1-6 A method for preparing a far- and near-infrared resistant polyester fabric is shown, which specifically includes the following steps:

[0039] S1. Melting polyester and adding 0.01%-10% far-infrared shielding particles; the particle size of the far-infrared shielding particles ranges from 5 nanometers to 5 microns; the far-infrared shielding particles include one or more metals, non-metals, metal oxides, or metal compounds, specifically including nickel, zirconium, titanium, zinc, silver, aluminum, silicon, copper, carbon, nitrogen, and sulfur; those skilled in the art can select appropriate particles to add according to needs;

[0040] The skilled person in the art may select a suitable method of adding particles in the prior art to add particles, such as a pre-dispersed masterbatch method and an in-situ polymerization dispersion method;

[0041] S2, melted polyester is made into a spinning solution for spinning, and then woven using an air-jet loom to obtain polyester cloth; the fineness of the spun single fiber ranges from 0.3 to 1.5 deniers; the air-jet loom uses a warp and weft yarn combination of 50D / 72FFDY×50D / 72F FDY, with a weaving density of 185×107 and a gram weight of 60-70g / m 2 ;

[0042] S3, the polyester cloth is cleaned and set aside, the alkali washing conditions are 0.4g / L-2g / L soda ash, and the alkali washing temperature is 80℃;

[0043] S4, dye solution preparation, selecting two or more disperse dyes to dye the polyester fabric, the disperse dyes matching the 700nm-1300nm infrared reflectivity curve, and the reflectivity is 10%-70%; disperse dyes include red, yellow, blue, navy blue, black, golden yellow and turquoise blue;

[0044] S5, preparing for dyeing, dissolving disperse dye in an organic solvent at a total concentration of 0.5% to 6%, adding an environmentally friendly carrier, a leveling agent, and a pH adjuster, wherein the environmentally friendly carrier includes modified lignin sulfonate;

[0045] S6, dyeing, heating at 2°C / min to 100-110°C and holding for 60 minutes; the final dyed color matches the target color, that is, matches the core parameters of the CIELAB color space of the target color, including: lightness, red-green axis, yellow-blue axis, chroma, and hue angle, and the reflectance curve of the fabric in the wavelength range of 700nm-1300nm deviates from the environmental target value within 5%;

[0046] During the dyeing process, the dye liquor is circulated in the dyeing device by the centrifugal pump 3; during the circulation process, the quality of the dye liquor circulated in the dyeing device is detected, and the dye concentration is detected in real time by the micro-spectrometer or optical fiber sensor at the dye liquor detection unit 4;

[0047] When accumulation of dye liquor pollutants is detected (i.e., when heavy metal content is too high or organic pollution is serious), the dye liquor should be completely replaced;

[0048] When completely replacing the dye liquor: first cool the dye liquor to below 90°C at a rate of 2°C / min, then drain the old liquid from dyeing tank 1; then inject 80°C hot water for a 5-minute circulation rinse to remove residual dyes and oligomers; inject the preheated new dye liquor into dyeing tank 1; finally, restart centrifugal pump 3 and adjust the flow rate and pressure to meet the process requirements;

[0049] When the dye concentration is lower than the set value, new dye solution is dynamically added and an equal amount of old dye solution is discharged. The discharged old dye solution is used to preheat the new dye solution. For example, when the dye concentration in the dye solution is lower than 1g / L, new dye solution is added to maintain the dyeing depth. If the concentration is still higher than 1g / L, it can be directly recycled 4-6 times, and only a small amount of deionized water needs to be added each time.

[0050] The specific operation of dynamically adding dye liquor includes: gradually adding premixed new dye liquor at a ratio of 20%-30% each time, that is, the amount of new dye liquor injected each time is 20%-30% of the amount of old dye liquor in the dyeing tank 1, and discharging an equal amount of old dye liquor when injecting new dye liquor; when adding new dye liquor, controlling the operation of the centrifugal pump 3 to maintain the flow rate of the circulating dye liquor ≥25L / (kg·min) to ensure that the new and old dye liquors are evenly mixed; after each injection of new dye liquor and after mixing, the dye concentration is detected. If the dye concentration is still lower than the set value, the above-mentioned new dye liquor injection operation is repeated. If the dye concentration is higher than the set value, the new dye injection is stopped;

[0051] S7, color fixing, after dyeing, use hydrosulfite and caustic soda to wash at 80℃ for 15 minutes to remove floating color and improve color fastness, and finally acid wash until the pH of the fabric is neutral to obtain the finished fabric.

[0052] This embodiment realizes the efficient preparation of far-infrared and near-infrared resistant polyester fabric. The fabric can not only effectively block far-infrared radiation, but also has a certain degree of protection against near-infrared light. Through a sophisticated preparation process, especially the precise dye selection and cyclic dyeing management in steps S4 to S6, it is ensured that the reflectivity of the fabric in a specific infrared band meets the design requirements, thereby improving the comprehensive protective performance of the fabric.

[0053] Second implementation method:

[0054] Figure 2-Figure 7 As shown, the dyeing device includes a dyeing tank 1 and a circulation pipe 2. The circulation pipe 2 includes an upper guide tank 21 and a lower guide pipe 22. The lower guide pipe 22 is connected to a drain pipe and communicates with a centrifugal pump 3. The drain pipe is used to discharge the old dye liquid.

[0055] The upper guide tank 21 is connected to a compensation pipe and communicates with the dyeing tank 1; a heater is installed in the upper guide tank 21; the compensation pipe is used to input new dye solution;

[0056] The centrifugal pump 3 is installed between the dyeing tank 1 and the circulation pipe 2, and the main output pipe and the dye liquid detection unit 4 are connected between the centrifugal pump 3 and the dyeing tank 1. The dye liquid detection unit 4 includes a shunt pipe 41 connected to the main output pipe, and an electrochemical sensor and an optical fiber in-situ sensor are installed in the shunt pipe 41. The dye liquid detection unit 4 detects the dye liquid concentration and impurity content during the dye liquid circulation process;

[0057] The dye solution detection unit 4 includes a sampling and analysis structure, which includes a detection box arranged outside the shunt tube 41. A branch tube 42 connected to the shunt tube 41 is provided in the detection box. At least two sampling tubes 43 are connected to the branch tube 42. The sampling tubes 43 are made of transparent material. The opening and closing of the sampling tubes 43 and the branch tubes 42 are both achieved by solenoid valves in the prior art.

[0058] One end of the sampling tube 43 is connected to the branch tube 42, and the other end is connected to a one-way valve, and the one-way valve is connected to the cleaning liquid input pipe. When the old dye liquid is discharged, the sampling tube 43 discharges the sampled dye liquid, and at the same time, the cleaning liquid is injected through the one-way valve to clean the sampling tube 43 and the branch tube 42, so that the sampling tube 43 is cleaned simultaneously when the old dye liquid is discharged.

[0059] A visual detection module and a spectrum detection module that match the sampling tubes 43 are provided in the detection box. The visual detection module and the spectrum detection module detect the two sampling tubes 43 respectively.

[0060] When the dye liquor circulates, part of the dye liquor is diverted to the dye liquor detection unit 4, and the dye liquor is detected in real time by the electrochemical sensor and the optical fiber in-situ sensor in the shunt tube 41 to preliminarily detect the heavy metal content and dye concentration. If the detection value reaches the set warning value or the set sampling inspection time point, the sampling analysis structure is controlled to open the branch tube 42. At this time, the dye liquor fills the branch tube 42. At this time, the spectral detection module detects the dye concentration and heavy metal content through spectroscopy, and the visual detection module collects images. Then, the turbidity change is analyzed by the HSV color model to determine the organic pollution status. The visual detection module and the spectral detection module both adopt existing technologies, and those skilled in the art can select appropriate spectral detection equipment and visual detection equipment in the existing technology for installation.

[0061] If the heavy metal content is greater than the set value or the organic pollution exceeds the set standard, the dye solution will be completely replaced;

[0062] The dye liquor detection unit 4 of this embodiment enables real-time monitoring of dye liquor concentration and rapid analysis of impurity content. During dye liquor circulation, electrochemical sensors can sensitively detect impurities such as heavy metal ions in the dye liquor, ensuring that the dye liquor quality meets production requirements. Simultaneously, an optical fiber in-situ sensor accurately measures dye concentration to maintain concentration stability during the dyeing process. When the detection value reaches a preset warning value, the system automatically triggers the sampling and analysis mechanism, collecting dye liquor samples through the branch pipe 42. Further in-depth analysis using the spectral detection module and the visual detection module effectively determines the organic contamination status. This series of detection and analysis measures not only improves dyeing accuracy but also effectively guarantees the quality and performance of the final fabric product.

[0063] The third implementation method:

[0064] Figure 3-Figure 7 As shown, a heat exchange unit 5 is installed at the output end of the centrifugal pump 3. The heat exchange unit 5 includes a main liquid infusion pipe 51 for connecting the centrifugal pump 3 and the circulation pipe 2. The outer side of the main liquid infusion pipe 51 is sleeved with an outer heat exchange shell 52. A heat exchange pipe 53 wrapped around the main liquid infusion pipe 51 is passed through the outer heat exchange shell 52. The input end of the heat exchange pipe 53 is connected to the secondary dye liquid tank, and the output end of the heat exchange pipe 53 is connected to the compensation pipe; the secondary dye liquid tank is used to prepare the compensation dye liquid, and an agitator and a quantitative feeding device are installed in the secondary dye liquid tank.

[0065] When preheating the new dyeing liquid during the full dyeing liquid replacement operation, the dyeing liquid tank 1 prepares the new dyeing liquid and inputs it into the heat exchange pipe 53. At the same time, 80° hot water is input into the outer heat exchange shell 52 (after the hot water heat exchange is completed and output from the outer heat exchange shell 52, the discharged hot water can be reheated and then injected into the dyeing tank 1 for cleaning). The new dyeing liquid in the heat exchange pipe 53 is preheated by the hot water in the outer heat exchange shell 52. After the preheated new dyeing liquid is input into the upper guide tank 21, the new dyeing liquid can be further heated to a specified temperature by the heater and then injected into the dyeing tank 1.

[0066] When dye liquid is added dynamically, the old dye liquid discharged preheats the new dye liquid. The old dye liquid discharged from the dyeing tank 1 is input into the main liquid infusion pipe 51, and the new dye liquid is input into the heat exchange pipe 53. The heat exchange pipe 53 exchanges heat with the main liquid infusion pipe 51, so that the new dye liquid in the heat exchange pipe 53 absorbs the waste heat of the old dye liquid. The old dye liquid discharged from the main liquid infusion pipe 51 is transported to the lower guide pipe 22 and discharged through the drain pipe, realizing the utilization of the waste heat of the old dye liquid before discharge. After the new dye liquid is input into the upper guide tank 21, it can be heated to a specified temperature by the heater and then injected into the dyeing tank 1.

[0067] The heat exchange unit 5 of this embodiment effectively preheats the new dye solution and fully utilizes the residual heat of the old dye solution. During a complete dye solution replacement, the new dye solution is preheated in the hot water within the outer heat exchange shell 52 via the heat exchange tube 53, raising the temperature of the new dye solution and reducing the energy required for subsequent heating, thereby saving energy. During the dynamic dye solution addition process, the residual heat of the old dye solution as it flows out of the main liquid infusion tube 51 is absorbed by the new dye solution within the heat exchange tube 53, achieving effective energy recovery and reuse, further improving energy utilization efficiency.

[0068] The fourth implementation method:

[0069] When dyeing S5, first use a low refractive index dye to pre-dye to form a base reflective layer, such as yellow dye, and the pre-dyeing temperature is 115°C;

[0070] After the pre-dyeing is completed, the dye solution in the dyeing tank 1 is replaced with a dye solution of a high refractive index dye by using the same comprehensive dye solution replacement operation as in the first embodiment or the third embodiment, and the main dyeing is performed superimposed;

[0071] High refractive index dyes such as navy blue and black dyes are heated gradually to 130℃ and then kept warm, and then dyed to the desired color;

[0072] This embodiment effectively enhances the reflective properties of polyester fabric within a specific infrared band by pre-dyeing with a low-refractive-index dye to form a base reflective layer, then applying a high-refractive-index dye for the main dyeing. This step-by-step dyeing method not only enhances the fabric's near- and far-infrared protection, but also results in a more uniform color and improved colorfastness in the final product. Furthermore, this embodiment retains the advantages of previous implementations, such as cyclic dyeing management, precise dye concentration control, and efficient energy utilization, ensuring the efficient production and excellent performance of far- and near-infrared-resistant polyester fabric.

[0073] The fifth implementation method:

[0074] The polyester fabric after S6 dyeing is sprayed with PU coating. The polyester fabric is sprayed with PU coating using the existing PU coating technology at 0.5g / m 2 The PU coating is sealed, and the formed polyester fabric that is resistant to far and near infrared has both infrared resistance and conductivity.

[0075] The far- and near-infrared protection polyester fabric of this embodiment achieves a combination of efficient protection and versatility. The introduction of PU coating not only further enhances the fabric's protection against far and near infrared light, but also gives the fabric good conductive properties, broadening its application scenarios.

[0076] In summary, this solution achieves efficient and accurate preparation of far- and near-infrared resistant polyester fabrics. Through cyclic dyeing management, real-time dye liquor detection, heat exchange unit 5, and step-by-step dyeing method, it not only improves the preparation efficiency but also ensures that the reflective performance of the fabric in a specific infrared band meets the design requirements.

[0077] In view of current actual needs, the protection scope of the above-mentioned implementation mode adopted in this application is not limited to this. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. A method for preparing a far- and near-infrared resistant polyester fabric, characterized by: The specific steps include: S1, melting the polyester and adding 0.01%-10% of far-infrared shielding particles; S2, preparing the molten polyester into a spinning solution for spinning, and then weaving the molten polyester using an air jet loom to obtain a polyester fabric; S3, the polyester cloth is cleaned and set aside, the alkali washing conditions are 0.4g / L-2g / L soda ash, and the alkali washing temperature is 80℃; S4, dye solution preparation, selecting two or more disperse dyes to dye the polyester fabric, the disperse dyes matching the 700nm-1300nm infrared reflectivity curve, and the reflectivity is 10%-70%; S5, prepare for dyeing, dissolve disperse dye in organic solvent at a total concentration of 0.5%-6%, add environmentally friendly carrier, leveling agent and pH adjuster; S6, dyeing, heating to 100-110°C at 2°C / min, keeping the temperature for 60 minutes, and circulating the dye solution in the dyeing device by a centrifugal pump (3) during the dyeing process; during the circulation process, the quality of the dye solution circulating in the dyeing device is detected, and when accumulation of pollutants in the dye solution is detected, the dye solution is completely replaced; when the dye concentration is lower than the set value, new dye solution is dynamically added and an equal amount of old dye solution is discharged, and the discharged old dye solution is used to preheat the input new dye solution; S7, color fixing, after dyeing, use hydrosulfite and caustic soda to wash at 80℃ for 15 minutes to remove floating color and improve color fastness, and finally acid wash until the fabric pH is neutral.

2. The method for preparing a far- and near-infrared resistant polyester fabric according to claim 1, characterized in that: The dyeing device comprises a dyeing tank (1) and a circulation pipe (2), the circulation pipe comprising an upper guide tank (21) and a lower guide pipe (22), the lower guide pipe (22) being connected to a drain pipe and communicating with a centrifugal pump (3), and the upper guide tank (21) being connected to a compensation pipe and communicating with the dyeing tank (1); The centrifugal pump (3) is installed between the dyeing tank (1) and the circulation pipe (2), and a main output pipe and a dye liquid detection unit (4) are connected between the centrifugal pump (3) and the dyeing tank (1). The dye liquid detection unit (4) comprises a shunt pipe (41) connected to the main output pipe, and an electrochemical sensor and an optical fiber in-situ sensor are installed in the shunt pipe (41); the dye liquid detection unit (4) detects the dye liquid concentration and impurity content during the dye liquid circulation process.

3. The method for preparing a far- and near-infrared resistant polyester fabric according to claim 2, characterized in that: The dye liquor detection unit (4) includes a sampling and analysis structure, which includes a detection box arranged outside the shunt tube (41), a branch tube (42) connected to the shunt tube (41) is arranged in the detection box, at least two sampling tubes (43) are connected to the branch tube (42), and a visual detection module and a spectrum detection module matched with the sampling tube (43) are arranged in the detection box.

4. The method for preparing a far- and near-infrared resistant polyester fabric according to claim 1, characterized in that: A heat exchange unit (5) is installed at the output end of the centrifugal pump (3), and the heat exchange unit (5) comprises a main liquid infusion pipe (51) for connecting the centrifugal pump (3) and the circulation pipe (2); an outer heat exchange shell (52) is sleeved on the outer side of the main liquid infusion pipe (51); a heat exchange pipe (53) wound around the main liquid infusion pipe (51) is passed through the outer heat exchange shell (52); the input end of the heat exchange pipe (53) is connected to the secondary dyeing liquid tank, and the output end of the heat exchange pipe (53) is communicated with the compensation pipe.

5. The method for preparing a far- and near-infrared resistant polyester fabric according to claim 1, characterized in that: The auxiliary dye liquid tank is used for preparing the compensation dye liquid, and an agitator and a quantitative feeding device are installed in the auxiliary dye liquid tank.

6. The method for preparing a far- and near-infrared resistant polyester fabric according to claim 1, characterized in that: The disperse dyes include red, yellow, blue, navy, black, golden yellow and turquoise blue.

7. The method for preparing a far- and near-infrared resistant polyester fabric according to claim 1, characterized in that: The particle size range of the far-infrared protection particles includes 5 nanometers to 5 micrometers, and the fineness range of the spun single fiber is: 0.3-1.5 deniers.

8. The method for preparing a far- and near-infrared resistant polyester fabric according to claim 1, characterized in that: During the S5 dyeing, a low-refractive-index dye is first used for pre-dyeing to form a base reflective layer, and then a high-refractive-index dye is superimposed for main dyeing.

9. A far- and near-infrared resistant polyester fabric obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The polyester fabric is sprayed with a PU coating.

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