Polyester fabric recovery method

Abstract

The invention discloses a polyester fabric recycling method. The polyester fabric recycling method comprises the following steps. And decolorizing the polyester fabric to form the decolorized polyester fabric. The decolorized polyester fabric is mixed with a tackifying material to form an initial feed. The initial feed is subjected to liquid polymerization to form a liquid polymerization product. The liquid polymerization product is refluxed to mix with the initial feed to form an intermediate feed. The intermediate feed is conducted to form a final polymerization product.

Description

Technical Field

[0001] This invention relates to a method for recycling polyester fabrics. Background Technology

[0002] The conventional physical (mechanical) recycling method for waste polyester (e.g., polyethylene terephthalate, PET) fabrics involves mixing them with PET flakes to increase their intrinsic viscosity (IV), thus facilitating subsequent spinning. However, due to the significant difference in IV between the fabric and PET flakes, even after mixing in a mixer and extruder, the mixing is only macroscopic, resulting in poor microscopic uniformity. Furthermore, the IV of both the fabric and PET flakes decreases after heat treatment, leading to poor IV stability (excessive variability) in the mechanically recycled PET fabric granules. This makes it impossible to effectively control the quality of IV, resulting in poor subsequent spinning processability, such as insufficient filament strength and easy breakage. Summary of the Invention

[0003] This invention provides a method for recycling polyester fabrics, which can improve the uniformity of the intrinsic viscosity of recycled polyester.

[0004] The present invention provides a method for recycling polyester fabrics, comprising the following steps: Decolorizing the polyester fabric to form a decolorized polyester fabric; mixing the decolorized polyester fabric with a thickening agent to form an initial feed; liquid polymerizing the initial feed to form a liquid polymerization product; refluxing the liquid polymerization product back to the initial feed for mixing to form an intermediate feed; and liquid polymerizing the intermediate feed to form a final polymerization product.

[0005] In one embodiment of the present invention, the weight ratio of the decolorized polyester fabric to the adhesive material is 5:95 to 80:20.

[0006] In one embodiment of the present invention, the temperature of the liquid polymerization is 210°C to 290°C, and the pressure of the liquid polymerization is 0.1 torr to 5.0 torr.

[0007] In one embodiment of the present invention, the residence time of the above-mentioned decolorized polyester fabric and the thickening material during liquid polymerization is about 5 minutes to 200 minutes.

[0008] In one embodiment of the present invention, the intrinsic viscosity of the final polymer product is 0.60 or higher.

[0009] In one embodiment of the present invention, the standard deviation of the intrinsic viscosity of the final polymer product is less than 0.0036.

[0010] In one embodiment of the present invention, the CIELAB color of the final polymer product is defined as having an L value of 70 or higher, an a value of -3.0 to +3.0, and a b value of -10.0 to +10.0.

[0011] In one embodiment of the present invention, the weight ratio of the reflux rate of the liquid polymerization product to the initial feed rate is 5:1 to 50:1.

[0012] In one embodiment of the present invention, the initial feed rate is equal to the final output rate of the polymerization product.

[0013] In one embodiment of the present invention, the aforementioned polyester fabric includes greige fabric, dyed fabric, or fabric containing a surface treatment agent.

[0014] In one embodiment of the present invention, the intrinsic viscosity (IV) of the above-mentioned polyester fabric is 0.50 to 0.70.

[0015] In one embodiment of the present invention, the intrinsic viscosity of the above-mentioned decolorized polyester fabric is 0.45 to 0.65.

[0016] In one embodiment of the present invention, the CIELAB color of the above-mentioned decolorized polyester fabric is defined as an L value of 85 or above, an a value of -5.0 to +5.0, and a b value of -15.0 to +15.0.

[0017] In one embodiment of the present invention, the above-mentioned decolorization treatment is carried out using solvent extraction or aqueous solution extraction.

[0018] In one embodiment of the present invention, the thickening material is PET bottle flakes, and the intrinsic viscosity of the PET bottle flakes is 0.75 to 0.95.

[0019] In one embodiment of the present invention, the aforementioned thickening material is PET bottle flakes, and the CIELAB color definition of PET bottle flakes is an L value of 80 or above, an a value of -2.0 to +2.0, and a b value of -4.0 to +4.0.

[0020] Based on the above, the polyester fabric recycling method of the present invention allows the liquid polymerization product to be repeatedly refluxed for liquid polymerization, which not only improves IV uniformity while increasing IV, but also improves the hue performance of the final polymerization product.

[0021] To further understand the features and technical content of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0022] Figure 1This is a schematic flowchart of a method for recycling polyester fabrics according to an embodiment of the present invention.

[0023] Figure 2 This is a cross-sectional schematic diagram of a liquid polymerization unit according to an embodiment of the present invention. Detailed Implementation

[0024] The embodiments of the present invention will now be described in detail. However, these embodiments are illustrative, and the present invention is not limited thereto.

[0025] In this document, the range expressed as "from one value to another" is a concise way of representing a range to avoid listing all the values ​​in that range in the specification. Therefore, the description of a particular range of values ​​covers any value within that range as well as the smaller range of values ​​defined by that value, just as the arbitrary value and the smaller range of values ​​are described in the explanatory text of the specification.

[0026] Figure 1 This is a schematic flowchart of a method 100 for recycling polyester fabrics according to an embodiment of the present invention.

[0027] Please refer to Figure 1 In step S1, firstly, the decolorized polyester fabric is mixed with a tackifying material to disperse the tackifying material substantially uniformly within the decolorized polyester fabric, thus forming an initial feed. The weight ratio of the decolorized polyester fabric to the tackifying material can be from 5:95 to 80:20. For example, the weight ratio of the decolorized polyester fabric to the tackifying material is 1:4, 1:2, or 1:1. The decolorized polyester fabric can be waste polyester fabric that has undergone decolorization treatment. For example, the waste polyester fabric is waste PET fabric, and the decolorized waste polyester fabric is decolorized PET fabric, but the polyester of the present invention is not limited to PET. In some embodiments, the waste PET fabric includes greige fabric, dyed fabric, or fabric containing a surface treatment agent. In some embodiments, the surface treatment agent contained in the waste PET fabric includes polyurethane (PU), acrylic, thermoplastic polyester elastomer (TPEE), or a combination thereof.

[0028] In some embodiments, the intrinsic viscosity (IV) of the waste PET fabric is approximately 0.50 to 0.70. In some embodiments, the intrinsic viscosity of the decolorized PET fabric is approximately 0.45 to 0.65 due to the thermal history of the decolorization process. In some embodiments, the decolorized PET fabric has a hue (CIELAB color definition) with an L value of 85 or higher, an a value of -5.0 to +5.0, and a b value of -15.0 to +15.0.

[0029] Decolorization is the process of removing dyes and other impurities from waste polyester fabrics to achieve a decolorizing effect. Decolorization can be carried out using solvent extraction or aqueous solution extraction, which respectively use solvents and aqueous solutions to extract dyes or destroy the functional groups that produce color, thereby achieving the decolorization effect.

[0030] Solvents used in solvent extraction methods may include aromatic hydrocarbon solvents, alcohol ether solvents, benzene alcohol solvents, alcohol solvents, or amide solvents. In some embodiments, aromatic hydrocarbon solvents include benzene, toluene, or xylene. In some embodiments, alcohol ether solvents include propylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, or anisole. In some embodiments, alcohol solvents include ethylene glycol, butanol, pentanol, or hexanol. In some embodiments, amide solvents include dimethylformamide, dimethylacetamide, or N-methylpyrrolidone. In some embodiments, the above solvents include propylene glycol monomethyl ether, anisole, dimethylacetamide, dimethylformamide, ethylene glycol, N-methylpyrrolidone, or combinations thereof.

[0031] The aqueous solution used in the aqueous extraction method may contain an alkali, a surfactant, a reducing agent, an oxidizing agent, or a combination thereof. In some embodiments, the aqueous solution used in the aqueous extraction method may contain sodium hydroxide, sodium hypochlorite, calcium hypochlorite, sodium thiosulfate, sodium dithionite, thiourea dioxide, or a combination thereof.

[0032] The thickening material can be a material with an intrinsic viscosity greater than that of the decolorized polyester fabric. For example, the thickening material is PET flakes, but the invention is not limited thereto. In some embodiments, the intrinsic viscosity of the PET flakes is about 0.75 to 0.95. In some embodiments, the PET flakes have a hue with an L value of about 80 or higher, an a value of about -2.0 to +2.0, and a b value of about -4.0 to +4.0.

[0033] Next, in step S2, the mixed decolorized polyester fabric and the tackifier (i.e., the initial feed) are fed into an extruder for extrusion to produce a molten mixture of the decolorized polyester fabric and the tackifier. The extruder may be equipped with a single screw or a twin screw, and the extrusion can be performed at a temperature above room temperature. In some embodiments, the extrusion temperature is 210°C to 290°C, for example, 220°C to 250°C, 250°C to 280°C, or 240°C to 270°C. In some embodiments, the extrusion time is 0.3 minutes to 30 minutes, for example, 1 minute to 10 minutes, 10 minutes to 20 minutes, or 15 minutes to 25 minutes.

[0034] Next, in step S3, the molten mixture of the decolorized polyester fabric and the tackifier is maintained at the extrusion temperature and filtered to further remove impurities, producing a filtered molten mixture. The molten mixture of the decolorized polyester fabric and the tackifier can be filtered through a sieve. In some embodiments, the sieve has a mesh size of 30 μm to 120 μm (e.g., 40 μm to 100 μm or 50 μm to 80 μm), but the invention is not limited thereto.

[0035] Next, in step S4, the filtered molten mixture is fed into a liquid polymerization unit for liquid polymerization to form a liquid polymerization product. Figure 2 This is a cross-sectional schematic diagram of a liquid polymerization unit 200 according to an embodiment of the present invention. The liquid polymerization unit 200 may include an input pipe 210, a static mixer 220, a liquid polymerization tank 230, a return pipe 240, and an output pipe 250. The input pipe 210 may be connected to the inlet of the static mixer 220. The outlet of the static mixer 220 may be connected to the inlet of the liquid polymerization tank 230. The outlet of the liquid polymerization tank 230 may be connected to the input end of the return pipe 240 and the output pipe 250, and the output end of the return pipe 240 may be connected to the inlet of the static mixer 220.

[0036] The liquid polymerization unit 200 may also include multiple valves V1, V2, and V3. For example, valve V1 may be installed on the input pipe 210, valve V2 may be installed on the return pipe 240, and valve V3 may be installed on the output pipe 250, for controlling the flow rate in each pipe.

[0037] The filtered molten mixture can enter the liquid polymerization unit 200 via inlet pipe 210. Next, the filtered molten mixture can enter the static mixer 220 via inlet pipe 210 for static mixing. Then, the filtered molten mixture can leave the static mixer 220 and enter the liquid polymerization tank 230 for liquid polymerization, forming a liquid polymerization product. Next, the liquid polymerization product can leave the liquid polymerization tank 230 and return to the static mixer 220 via return pipe 240 to mix with other filtered molten mixtures or liquid polymerization products, forming an intermediate feed; alternatively, the liquid polymerization product can leave the liquid polymerization unit 200 as the final polymerization product via outlet pipe 250. The weight ratio of the return flow rate of the liquid polymerization product to the static mixer 220 to the feed rate of the filtered molten mixture entering the static mixer 220 can be 5:1 to 50:1, for example, 10:1 to 40:1 or 20:1 to 30:1. Through the reflux mechanism of the reflux pipe 240, the liquid polymerization product can be refluxed to the static mixer 220 multiple times to mix with other filtered molten mixtures or liquid polymerization products, and enter the liquid polymerization tank 230 multiple times for liquid polymerization. This allows the decolorized polyester fabric and the thickening material to be mixed uniformly at the microscopic level, and the final polymerization product can have a stable and uniform IV (small variation), thereby improving the processability and quality of subsequent spinning.

[0038] The liquid polymerization tank 230 may include a sprayer 232, a retention tank 234, and a return pipe 236. The sprayer 232 may have an orifice diameter of 0.01 mm to 10 mm (e.g., 0.05 mm to 5.0 mm). Through the sprayer 232, the filtered molten mixture and liquid polymerization product can be sprayed more evenly into the retention tank 234 of the liquid polymerization tank 230, where liquid polymerization takes place. Afterward, the product is discharged through the return pipe 236 to the return pipe 240 and the output pipe 250.

[0039] During operation of the liquid polymerization unit 200, the liquid polymerization unit 200 may be maintained at a temperature between 210°C and 290°C (e.g., 220°C to 280°C), and the liquid polymerization tank 230 may be maintained at a pressure between 0.1 torr and 5.0 torr (e.g., 0.2 torr to 3.0 torr). In some embodiments, the residence time for liquid polymerization of the decolorized polyester fabric and the tackifier is approximately 5 minutes to 200 minutes (e.g., 10 minutes to 100 minutes). In some embodiments, during operation of the liquid polymerization unit 200, a filtered molten mixture may be continuously fed into the liquid polymerization unit 200, and the final polymerization product may be continuously discharged from the liquid polymerization unit 200. In some embodiments, the amount of filtered molten mixture fed is approximately equal to the amount of the final polymerization product discharged.

[0040] Next, in step S5, the final polymerization product leaving the liquid polymerization unit 200 can be cooled. Then, in step S6, the cooled final polymerization product can be granulated to produce mechanically recycled polyester fabric granules for subsequent applications. In some embodiments, the mechanically recycled polyester fabric granules have an IV of 0.60 or higher, an IV standard deviation of less than 0.0036, an L value of 70 or higher, an a value of -3.0 to +3.0, and a b value of -10.0 to +10.0. The mechanically recycled polyester fabric granules can be used in spinning, weaving, and dyeing and finishing to form a waste fabric recycling system.

[0041] The following examples illustrate in detail the method for recycling polyester fabrics proposed in this invention. However, these examples are not intended to limit the scope of the invention.

[0042] <Preparation of Solvent-Decolorized PET Fabrics Using Solvent Extraction>

[0043] Take 108.7 kg of waste PET fabric, with an intrinsic viscosity of approximately 0.55, an L value of approximately 22.4, an a value of approximately 2.7, and a b value of approximately 2.8. The fabric contains 8.7 kg of dye and 100 kg of PET. Next, cut it into 3 cm squares and place it in a 1m... 3 The fabric was placed in a mixing tank. Next, 600 kg of dimethylacetamide (DMAc) was added to the mixing tank, heated to 130°C, and stirred for 30 minutes. The DMAc was then separated by filtering through a 1 cm filter. The fabric was then returned to the mixing tank, and 500 kg of DMAc was added. The mixture was heated to 130°C and stirred for 30 minutes, and the DMAc was separated by filtering. This process was repeated four times. The fabric was then dried in an oven at 120°C and 5 torr for 6 hours. The dried decolorized PET fabric weighed 96.2 kg, with an intrinsic viscosity of approximately 0.48, an L value of approximately 90.1, an a value of approximately 0.9, and a b value of approximately 3.2. 962 kg of solvent-decolorized PET fabric was prepared in this manner.

[0044] <Preparation of Aqueous-Aqueous Decolorized PET Fabrics Using Aqueous Extraction>

[0045] Take 108.7 kg of waste PET fabric, with an intrinsic viscosity of approximately 0.55, an L value of approximately 22.4, an a value of approximately 2.7, and a b value of approximately 2.8. The fabric contains 8.7 kg of dye and 100 kg of PET. Next, cut it into 3 cm squares and place it in a 2m... 3The mixture was placed in a stirring tank. Next, 1,000 kg of water, 5 kg of NaOH, and 3 kg of sodium thiosulfate were added to the stirring tank, and the mixture was heated to 137°C and held for 30 minutes. The tank was pressurized with nitrogen at 5 bar, and then the water was drained. This process was repeated once. Then, another 1,000 kg of water and 3 kg of calcium hypochlorite were added, and the mixture was heated to 137°C and held for 30 minutes. The tank was pressurized with nitrogen at 5 bar, and then the water was drained. Next, the fabric was dried in an oven at 120°C and 5 torr for 6 hours. The dried decolorized PET fabric weighed 97.8 kg, with an intrinsic viscosity of approximately 0.50, an L value of approximately 89.0, an a value of approximately 1.2, and a b value of approximately 8.4. 978 kg of aqueous solution decolorized PET fabric was prepared in this manner.

[0046] <PET bottle tablets>

[0047] Take a used PET bottle, remove the cap and label, break it into 3 cm square pieces, wash it with an aqueous solution containing surfactant, rinse it with water, and then dry it in an oven at 105°C for 6 hours. The resulting PET bottle flakes have an intrinsic viscosity of approximately 0.81, an L value of approximately 85, an a value of approximately 0.7, and a b value of approximately 1.4.

[0048] Example 1

[0049] Please also refer to Figure 1 and Figure 2 200 kg of solvent-decolorized PET fabric and 800 kg of PET bottle flakes are mixed to form the initial feed. The initial feed is injected into a twin-screw extruder at a flow rate of 6 kg / min and the extruder temperature is 260°C. The extruded molten PET is then filtered through a 60 μm mesh. The filtered molten PET is then fed into the liquid polymerization unit 200 for liquid polymerization to form a liquid polymerization product, such as liquid polymerized PET.

[0050] More specifically, the filtered molten PET (feed rate approximately 6 kg / min) enters the static mixer 220 and mixes with the liquid polymerized PET that is returned to the static mixer 220 via the return pipe 240 (return flow rate approximately 60 kg / min). After mixing in the static mixer 220, the two streams of fluid are sprayed into the retention tank 234 through a sprayer with a 1.0 mm orifice. The temperature in the retention tank 234 is 265°C, and the pressure is 0.5 torr. The weight of the filtered molten PET and liquid polymerized PET retained in the retention tank 234 is approximately 150 kg. After multiple recirculations and liquid polymerizations, the final polymerization product is discharged from the liquid polymerization tank 230 at a rate of 6 kg / min. The residence time of the filtered molten PET in the retention tank 234 is approximately 25 minutes. Subsequently, the final polymerization product was cooled and solidified to produce recycled PET granules. The quality analysis of the recycled PET granules was performed, and the results showed that the IV was approximately 0.65, the standard deviation of IV was approximately 0.0020, the L value was approximately 78, the a value was approximately 0.9, and the b value was approximately 2.8. This indicates that the IV was effectively improved, the distribution of IV was highly stable, and the color was excellent.

[0051] Example 2

[0052] PET recycled pellets were manufactured using a method largely the same as in Example 1, with the main difference being the change in the feed rate and return flow rate of solvent-decolorized PET fabric and PET bottle flakes. The quality analysis results of the PET recycled pellets in Example 2 are shown in Table 1.

[0053] Example 3

[0054] PET recycled pellets were manufactured using a method largely similar to that of Example 1, with the main differences being the changes in the feed rate, reflux rate, liquid polymerization temperature, and liquid polymerization pressure of the solvent-decolorized PET fabric and PET bottle flakes. The quality analysis results of the PET recycled pellets of Example 3 are shown in Table 1.

[0055] Examples 4-6

[0056] The PET recycled pellets of Examples 4 to 6 were manufactured using a method substantially the same as that of Examples 1 to 3, with the main difference being that aqueous solution-decolorized PET fabric was used instead of solvent-decolorized PET fabric. The quality analysis results of the PET recycled pellets of Examples 4 to 6 are shown in Table 1.

[0057] The preparation methods and test results of Examples 1 to 6 are summarized in Table 1 below.

[0058] [Table 1]

[0059]

[0060]

[0061] Comparative Example 1

[0062] PET recycled granules are manufactured using a method largely similar to that in Example 1, the main difference being that the liquid polymerization unit 200 is not equipped with a static mixer 220 and a return pipe 240. In other words, the filtered molten PET in the input pipe 210 directly enters the liquid polymerization tank 230 for liquid polymerization, and the liquid polymerized PET flowing out of the liquid polymerization tank 230 leaves the liquid polymerization unit 200 directly through the output pipe 250, without flowing back to the liquid polymerization tank 230 for further liquid polymerization. Therefore, the weight ratio of return flow rate to feed rate is 0.

[0063] Comparative Example 2

[0064] PET recycled granules are manufactured using a method largely similar to that in Example 2, the main difference being that the liquid polymerization unit 200 is not equipped with a static mixer 220 and a return pipe 240. In other words, the filtered molten PET in the input pipe 210 directly enters the liquid polymerization tank 230 for liquid polymerization, and the weight ratio of return flow rate to feed rate is 0.

[0065] Comparative Example 3

[0066] PET recycled pellets were manufactured in a manner substantially the same as in Example 3, except that the liquid polymerization unit 200 was not equipped with a static mixer 220 and the weight ratio of reflux flow rate to feed rate was 1.0.

[0067] Comparative Example 4

[0068] PET recycled granules are manufactured in a manner largely the same as in Example 4, with the main difference being that the liquid polymerization unit 200 is not equipped with a static mixer 220 and a return pipe 240. In other words, the filtered molten PET in the input pipe 210 directly enters the liquid polymerization tank 230 for liquid polymerization, and the weight ratio of return flow to feed flow is 0.

[0069] Comparative Example 5

[0070] PET recycled granules are manufactured in a manner largely the same as in Example 5, with the main difference being that the liquid polymerization unit 200 is not equipped with a static mixer 220 and a return pipe 240. In other words, the filtered molten PET in the input pipe 210 directly enters the liquid polymerization tank 230 for liquid polymerization, and the weight ratio of return flow to feed flow is 0.

[0071] Comparative Example 6

[0072] PET recycled pellets were manufactured in a manner substantially the same as in Example 6, except that the liquid polymerization unit 200 was not equipped with a static mixer 220 and the weight ratio of reflux flow rate to feed rate was 1.0.

[0073] The preparation methods and test results of Comparative Examples 1 to 6 are summarized in Table 2 below.

[0074] [Table 2]

[0075]

[0076]

[0077] As can be seen from the quality analysis results in Table 1, the standard deviation of IV for the recycled PET pellets in Examples 1 to 6 is less than 0.0036, indicating high IV stability, with IV values ​​reaching above 0.60. Furthermore, the L values ​​for Examples 1 to 6 are all greater than 70, the a values ​​are all less than 2.5, and the b values ​​are all less than 8.5, indicating good color.

[0078] As can be seen from the quality analysis results in Table 2, the standard deviation of IV in the recycled PET particles of Comparative Examples 1 to 6 is greater than 0.004, indicating that they cannot stabilize the IV distribution and cannot effectively control IV. Furthermore, the L values ​​of Examples 1 to 6 are greater than those of Comparative Examples 1 to 6, the a values ​​of Examples 1 to 6 are less than those of Comparative Examples 1 to 6, and the b values ​​of Examples 1 to 6 are less than those of Comparative Examples 1 to 6, indicating that the hue performance of Examples 1 to 6 is significantly better than that of Comparative Examples 1 to 6.

[0079] In summary, the polyester fabric recycling method of the present invention, by repeatedly refluxing the liquid polymerization product to repeat the liquid polymerization, can not only effectively stabilize the IV distribution to improve IV uniformity while increasing IV, but also improve the hue performance of the recycled polyester.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recycling a polyester fabric, characterized by, comprising: bleaching the polyester fabric to form a bleached polyester fabric; mixing the bleached polyester fabric with a tackifying material to form an initial charge; liquid polymerizing the initial charge to form a liquid polymerization product; backflowing the liquid polymerization product to mix with the initial charge to form an intermediate charge; and liquid polymerizing the intermediate charge to form a final polymerization product.

2. The method of claim 1, wherein, The bleached polyester fabric and the tackifying material are mixed in a weight ratio of 5:95 to 80:

20.

3. The method of claim 1, wherein, The liquid polymerization is performed at a temperature of 210°C to 290°C and a pressure of 0.1 torr to 5.0 torr.

4. The method of claim 1, wherein, The bleached polyester fabric and the tackifying material are mixed in a weight ratio of 5:95 to 80:

20.

5. The method of claim 1, wherein, The final polymerization product has an intrinsic viscosity of 0.60 or more.

6. The method of claim 1, wherein, The final polymerization product has an intrinsic viscosity standard deviation of less than 0.0036.

7. The method of claim 1, wherein, The final polymerization product has a CIELAB color definition of an L value of 70 or more, an a value of -3.0 to +3.0, and a b value of -10.0 to +10.

0.

8. The method of claim 1, wherein, The backflow amount of the liquid polymerization product and the charge amount of the initial charge are mixed in a weight ratio of 5:1 to 50:

1.

9. The method of claim 8, wherein, The charge amount of the initial charge is equal to the discharge amount of the final polymerization product.

10. The method of claim 1, wherein, The polyester fabric includes a greige fabric, a dyed fabric, or a fabric containing a surface treatment agent.

11. The method of claim 1, wherein, The polyester fabric has an intrinsic viscosity (IV) of 0.50 to 0.

70.

12. The method of claim 1, wherein, The bleached polyester fabric has an intrinsic viscosity of 0.45 to 0.

65.

13. The method of claim 1, wherein, The bleached polyester fabric has a CIELAB color definition of an L value of 85 or more, an a value of -5.0 to +5.0, and a b value of -15.0 to +15.

0.

14. The method of claim 1, wherein, The bleaching is performed using a solvent extraction method or an aqueous solution extraction method.

15. The method of claim 1, wherein, The tackifying material is a bale strip having an intrinsic viscosity of 0.75 to 0.

95.

16. The method of claim 1, wherein, The tackifying material is a bale strip having a CIELAB color definition of an L value of 80 or more, an a value of -2.0 to +2.0, and a b value of -4.0 to +4.0.

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