Method for preparing polyester fiber from waste polyester raw material
By introducing epoxy chain extenders into waste polyester fibers and preparing them by reacting sulfonic acid triazine phenol with epichlorohydrin, the problem of poor mechanical properties of waste polyester fibers was solved, enabling the preparation and reuse of high-performance polyester fibers and improving the mechanical and dyeing properties of the fibers.
Patent Information
- Application Number
- CN202511266962.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-05
- Publication Date
- 2025-11-11
AI Technical Summary
The existing technology for preparing polyester fibers from waste polyester has poor mechanical properties, resulting in insufficient mechanical strength and making it difficult to achieve efficient secondary utilization.
Epoxy chain extenders were used to modify recycled polyester. The epoxy chain extenders were prepared by reacting sulfonic acid triazine phenol with epichlorohydrin under alkaline conditions. By reacting with the end groups of polyester, the molecular weight was increased. Combined with sulfonate structure, siloxane chain and triazine ring structure, the mechanical properties and dyeing properties of the fiber were improved.
It increases the molecular weight and mechanical strength of polyester fibers, enhances the softness and dyeing properties of the fibers, realizes the efficient secondary utilization of waste polyester, and improves the added value and wearing comfort of the fibers.
Smart Images
Figure QLYQS_1
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polyester fiber technology, specifically relating to a method for preparing polyester fibers using waste polyester raw materials. Background Technology
[0002] Nowadays, polyester bottles are receiving increasing attention due to their excellent performance, with demand increasing year by year. They have relatively mature technology and are very durable. However, at the same time, the environmental pollution and resource waste caused by waste PET bottles have also attracted attention. Therefore, the recycling of waste PET bottles has become a widely concerned issue.
[0003] PET bottles are mainly made of polyethylene terephthalate. Currently, physical and chemical methods are used to process waste polyester bottles. Physical recycling mainly refers to cleaning the polyester bottles before reuse. Chemical recycling is divided into the following types: (1) Recycling technology for direct fiber production. First, waste polyester bottles are sorted and recycled, then purified and dried. During granulation, the required additives are added for processing to meet the requirements for spinning. No chemical degradation is required in this process. The obtained recycled polyester raw materials can be made into short fibers by melt spinning, and then processed to produce some daily necessities. (2) Waste polyester bottle materials are transformed into polyester resin raw materials through alcoholysis and hydrolysis processes. This method degrades waste polyester bottles, breaking down large molecules into smaller molecules, and then applies them to the polyester production process. Using this method to recycle waste polyester bottles can achieve high economic benefits, but the process is complex and consumes a lot of material and human resources. Currently, the most common application is to directly produce fibers from recycled PET bottles. However, compared with virgin polyester materials, waste polyester is severely degraded, and the reduction in molecular weight leads to poor mechanical strength of waste polyester products. Therefore, it is necessary to provide a method for preparing polyester fibers from waste polyester raw materials, so as to produce high-performance polyester fibers and realize the secondary utilization of waste. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing polyester fibers using waste polyester raw materials, thereby solving the problem of poor mechanical properties of polyester fibers prepared from existing waste polyester materials.
[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing polyester fibers using waste polyester raw materials includes the following steps: (1) The waste polyester raw materials are sorted, cleaned, crushed and dried to obtain recycled polyester; (2) The recycled polyester is transported to a drying device and dried at 120-140℃ for 10-30 min and at 140-170℃ for 3-6 h. Then the dried recycled polyester and epoxy chain extender are added to a screw extruder for melt mixing. The melt obtained by melt mixing is transported to the spinning unit to obtain raw silk. The raw silk is oiled, crimped and drawn to obtain polyester fiber.
[0006] The mass ratio of dried recycled polyester to epoxy chain extender is 100:0.5-3.
[0007] Furthermore, the epoxy chain extender is prepared by chemical reaction of sulfonic acid triazine phenol and epichlorohydrin.
[0008] Furthermore, the molecular structure of the sulfonic acid triazine phenol is as follows: .
[0009] Furthermore, the preparation process of the epoxy chain extender is as follows: Sulfonated triazine phenol, potassium hydroxide, and anhydrous ethanol were added sequentially to a flask and stirred for 3-5 minutes. Epichlorohydrin was then added, and the mixture was heated to 70°C under a nitrogen atmosphere and stirred for 4 hours. The temperature was then lowered to 20-30°C, and potassium hydroxide solution was added dropwise. After the addition was complete, the temperature was raised to 60°C, and the mixture was stirred for 6-8 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, and the filtrate was evaporated to dryness to obtain the epoxy chain extender.
[0010] Furthermore, the ratio of sulfonic acid triazine phenol, potassium hydroxide, anhydrous ethanol, epichlorohydrin, and potassium hydroxide solution is 26.5-28 g: 2.8 g: 200-300 mL: 9.25 g: 8.42 g, and the mass fraction of potassium hydroxide solution is 35-45%. Sulfonic acid triazine phenol and epichlorohydrin react under alkaline conditions via nucleophilic substitution ring-opening-ring-closing reaction to obtain an epoxy chain extender.
[0011] Furthermore, the preparation process of the sulfonic acid triazine phenol is as follows: S1. Add cyanuric chloride to a flask containing acetone, cool to 0-5℃, and add potassium hydroxide aqueous solution containing aminoethanesulfonic acid dropwise while stirring. During the dropwise addition, maintain the pH of the system at 7-8 with 1mol / L potassium carbonate solution. After the dropwise addition is complete, stir the reaction for 12h. After the reaction is complete, filter to obtain potassium sulfonate dichlorotriazine. S2. Add potassium sulfonate dichlorotriazine to a flask containing deionized water. Under nitrogen protection, stir and heat to 20-25℃. Add an acetone solution of p-aminophenol dropwise. During the dropwise addition, maintain the pH of the system at 7-8 with 1 mol / L potassium carbonate solution. Stir the reaction for 12 hours. After the reaction is completed, remove the acetone by vacuum distillation to obtain the intermediate product. S3. Add 1,3-bis(3-aminopropyl)tetramethyldisiloxane and potassium carbonate to a flask containing anhydrous ethanol. Under nitrogen protection, stir and heat to 80-85°C. Add the aqueous solution of the intermediate product in three equal batches, with an interval of 2-3 min between each batch. Stir and react for 12 h. After the reaction is complete, remove the anhydrous ethanol by rotary evaporation. Wash the rotary evaporated product with ethyl acetate. Then concentrate, crystallize and dry the washed product to obtain sulfonic acid triazine phenol.
[0012] Furthermore, the mass ratio of cyanuric chloride to aminoethanesulfonic acid in S1 is 9.23:6.3-6.8, and the potassium hydroxide aqueous solution containing aminoethanesulfonic acid is composed of aminoethanesulfonic acid and 1 mol / L potassium hydroxide aqueous solution in a dosage ratio of 6.3-6.8 g:55 mL.
[0013] Furthermore, the mass ratio of potassium sulfonate dichlorotriazine to p-aminophenol in S2 is 15.5-16.0:6, and the acetone solution of p-aminophenol is composed of p-aminophenol and acetone in a dosage ratio of 6g:55mL.
[0014] Furthermore, the mass ratio of 1,3-bis(3-aminopropyl)tetramethyldisiloxane, potassium carbonate, and intermediate product in S3 is 5.48 g: 5.5 g: 21.5-22 g, and the aqueous solution of the intermediate product is composed of the intermediate product and deionized water in a ratio of 1 g: 10 mL.
[0015] Furthermore, the waste polyester raw material is waste polyester cola bottle (intrinsic viscosity 0.58 g / dl).
[0016] Furthermore, the screw extruder has a screw diameter of 65mm, a screw length-to-diameter ratio of 30, and five temperature zones, with temperatures of 235-240℃, 250-260℃, 260-265℃, 265-270℃, and 265-270℃ respectively.
[0017] Furthermore, the main parameters of the spinning unit are as follows: melt filter filtration accuracy 25μm, spinning box temperature 270-275℃, spinneret orifice number 40-48, spinneret orifice diameter 0.2-0.4mm, spinneret orifice length-to-diameter ratio 1-1.5, cooling air temperature 25-30℃, humidity 55-65%, wind speed 2-4m / min, and spinning speed 1500-2500m / min.
[0018] The beneficial effects of this invention are: This invention provides a method for preparing polyester fiber using waste polyester raw materials. The recycled polyester is modified by using an epoxy chain extender. The active epoxy groups on the epoxy chain extender can react with the polyester end groups (hydroxyl / carboxyl groups) to connect polyester chain segments, effectively increasing the molecular weight, improving the intrinsic viscosity of the recycled polyester, and improving its extrusion processing performance. Furthermore, compared with existing polyester chain extenders (such as bisoxazolinebenzene and pyromellitic anhydride), the polyester chain extender in this application also carries sulfonate structures, siloxane chains (-Si-O-Si-), and triazine and benzene ring structures. Among them, the sulfonate group is an anionic group, which has good binding properties with cationic dyes. Therefore, the introduction of the sulfonate group effectively improves the dyeing rate of polyester fibers and has good color fastness. The siloxane chain has high molecular chain flexibility, which increases the softness of polyester fibers and enhances the added value and wearing comfort of polyester fiber products. The triazine and benzene ring structures are rigid reinforcing units, which are beneficial to improving the mechanical strength and thermal stability of polyester fibers. In summary, the epoxy chain extender of this invention is a recycled polyester auxiliary agent that integrates "chain repair, toughening, reinforcement, flammability, and heat resistance," which not only realizes the secondary utilization of waste polyester but also endows recycled polyester fibers with good performance characteristics. Detailed Implementation
[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0020] The following is a detailed description with reference to specific examples.
[0021] Preparation Example 1 An epoxy chain extender, the preparation process is as follows: 26.5 g of sulfonic acid triazine phenol, 2.8 g of potassium hydroxide, and 200 mL of anhydrous ethanol were added sequentially to a flask. After stirring for 3 min, 9.25 g of epichlorohydrin was added. The mixture was heated to 70 °C under a nitrogen atmosphere and stirred for 4 h. Then, the temperature was lowered to 20 °C, and 8.42 g of 35 wt% potassium hydroxide solution was added dropwise. After the addition was complete, the temperature was raised to 60 °C and stirred for 6 h. After the reaction was complete, the mixture was cooled to room temperature, filtered, and the filtrate was evaporated to dryness to obtain the epoxy chain extender.
[0022] The preparation process of sulfonic acid triazine phenol is as follows: S1. Add 9.23g of cyanuric chloride to a flask containing 100mL of acetone, cool to 0℃, and add dropwise a mixture of 6.3g of aminoethanesulfonic acid and 55mL of 1mol / L potassium hydroxide aqueous solution while stirring. During the dropwise addition, maintain the pH of the system at 7 with 1mol / L potassium carbonate solution. After the dropwise addition is complete, stir the reaction for 12h. After the reaction is complete, filter to obtain potassium sulfonate dichlorotriazine. S2. Add 15.5g of potassium sulfonate dichlorotriazine to a flask containing 150mL of deionized water. Under nitrogen protection, stir and heat to 20℃. Add a mixed solution of 6g of p-aminophenol and 55mL of acetone dropwise. During the dropwise addition, maintain the pH of the system at 7 with 1mol / L potassium carbonate solution. Stir and react for 12h. After the reaction is completed, remove the acetone by vacuum distillation to obtain the intermediate product. S3. Add 5.48 g of 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 5.5 g of potassium carbonate to a flask containing 100 mL of anhydrous ethanol. Under nitrogen protection, stir and heat to 80 °C. Add in three equal batches a solution consisting of 21.5 g of intermediate product and 215 mL of deionized water, with an interval of 2 min between each batch. Stir and react for 12 h. After the reaction is complete, remove the anhydrous ethanol by rotary evaporation. Wash the rotary evaporated product with ethyl acetate. Then concentrate, crystallize and dry the washed product to obtain sulfonic acid triazine phenol.
[0023] Preparation Example 2 An epoxy chain extender, the preparation process is as follows: 27g of sulfonic acid triazine phenol, 2.8g of potassium hydroxide, and 250mL of anhydrous ethanol were added sequentially to a flask. After stirring for 4 minutes, 9.25g of epichlorohydrin was added. The mixture was heated to 70°C under a nitrogen atmosphere and stirred for 4 hours. Then, the temperature was lowered to 25°C, and 8.42g of 40wt% potassium hydroxide solution was added dropwise. After the addition was complete, the temperature was raised to 60°C and stirred for 7 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, and the filtrate was evaporated to dryness to obtain the epoxy chain extender.
[0024] The preparation process of sulfonic acid triazine phenol is as follows: S1. Add 9.23g of cyanuric chloride to a flask containing 130mL of acetone, cool to 2℃, and add dropwise a mixture of 6.5g of aminoethanesulfonic acid and 55mL of 1mol / L potassium hydroxide aqueous solution while stirring. During the dropwise addition, maintain the pH of the system at 7 with 1mol / L potassium carbonate solution. After the dropwise addition is complete, stir the reaction for 12h. After the reaction is complete, filter to obtain potassium sulfonate dichlorotriazine. S2. Add 15.8 g of potassium sulfonate dichlorotriazine to a flask containing 180 mL of deionized water. Under nitrogen protection, stir and heat to 22 °C. Add a mixed solution of 6 g of p-aminophenol and 55 mL of acetone dropwise. During the dropwise addition, maintain the pH of the system at 7 with 1 mol / L potassium carbonate solution. Stir and react for 12 h. After the reaction is complete, remove the acetone by vacuum distillation to obtain the intermediate product. S3. Add 5.48 g of 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 5.5 g of potassium carbonate to a flask containing 100 mL of anhydrous ethanol. Under nitrogen protection, stir and heat to 85 °C. Add in three equal batches a solution consisting of 21.5 g of intermediate product and 220 mL of deionized water, with an interval of 2 min between each batch. Stir and react for 12 h. After the reaction is complete, remove the anhydrous ethanol by rotary evaporation. Wash the rotary evaporated product with ethyl acetate. Then concentrate, crystallize and dry the washed product to obtain sulfonic acid triazine phenol.
[0025] Preparation Example 3 An epoxy chain extender, the preparation process is as follows: 28g of sulfonic acid triazine phenol, 2.8g of potassium hydroxide, and 300mL of anhydrous ethanol were added sequentially to a flask. After stirring for 5 minutes, 9.25g of epichlorohydrin was added. The mixture was heated to 70°C under a nitrogen atmosphere and stirred for 4 hours. Then, the temperature was lowered to 30°C, and 8.42g of 45wt% potassium hydroxide solution was added dropwise. After the addition was complete, the temperature was raised to 60°C, and the mixture was stirred for 8 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, and the filtrate was evaporated to dryness to obtain the epoxy chain extender.
[0026] The preparation process of sulfonic acid triazine phenol is as follows: S1. Add 9.23g of cyanuric chloride to a flask containing 150mL of acetone, cool to 5℃, and add dropwise a mixture of 6.8g of aminoethanesulfonic acid and 55mL of 1mol / L potassium hydroxide aqueous solution while stirring. During the dropwise addition, maintain the pH of the system at 8 with 1mol / L potassium carbonate solution. After the dropwise addition is complete, stir the reaction for 12h. After the reaction is complete, filter to obtain potassium sulfonate dichlorotriazine. S2. Add 16.0 g of potassium sulfonate dichlorotriazine to a flask containing 200 mL of deionized water. Under nitrogen protection, stir and heat to 25 °C. Add a mixed solution of 6 g of p-aminophenol and 55 mL of acetone dropwise. During the dropwise addition, maintain the pH of the system at 8 with 1 mol / L potassium carbonate solution. Stir and react for 12 h. After the reaction is complete, remove the acetone by vacuum distillation to obtain the intermediate product. S3. Add 5.48 g of 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 5.5 g of potassium carbonate to a flask containing 100 mL of anhydrous ethanol. Under nitrogen protection, stir and heat to 85 °C. Add three equal portions of a solution consisting of 22 g of intermediate product and 220 mL of deionized water, with a 3 min interval between each portion. Stir and react for 12 h. After the reaction is complete, remove the anhydrous ethanol by rotary evaporation. Wash the rotary evaporated product with ethyl acetate. Then concentrate, crystallize and dry the washed product to obtain sulfonic acid triazine phenol.
[0027] Compare with Example 1 This comparative example is sulfonic acid triazine phenol, and the preparation process is the same as in Preparation Example 1.
[0028] Example 1 A method for preparing polyester fibers using waste polyester raw materials includes the following steps: (1) The waste polyester raw materials are sorted, cleaned, crushed and dried to obtain recycled polyester; (2) The recycled polyester is transported to a drying device and dried at 120°C for 10 min and at 140°C for 3 h. Then the dried recycled polyester and the epoxy chain extender of Preparation Example 1 are added to a screw extruder for melt mixing. The melt obtained by melt mixing is transported to the spinning unit to obtain raw silk. The raw silk is oiled, crimped and stretched to obtain polyester fiber.
[0029] In this case, the mass ratio of dried recycled polyester to epoxy chain extender in Example 1 was 100:0.5.
[0030] The waste polyester raw material is waste polyester cola bottles (intrinsic viscosity 0.58 g / dl).
[0031] The screw extruder has a screw diameter of 65mm and a length-to-diameter ratio of 30. It has five temperature zones with temperatures of 235℃, 250℃, 260℃, 265℃, and 265℃, respectively.
[0032] The main parameters of the spinning unit are: melt filter filtration accuracy 25μm, spinning box temperature 270℃, spinneret orifice number 40, spinneret orifice diameter 0.2mm, spinneret orifice length-to-diameter ratio 1, cooling air temperature 25℃, humidity 55%, air velocity 2m / min, and spinning speed 1500m / min.
[0033] Example 2 A method for preparing polyester fibers using waste polyester raw materials includes the following steps: (1) The waste polyester raw materials are sorted, cleaned, crushed and dried to obtain recycled polyester; (2) The recycled polyester is transported to a drying device and dried at 130°C for 20 min and at 150°C for 4 h. Then the dried recycled polyester and the epoxy chain extender of Preparation Example 1 are added to a screw extruder for melt mixing. The melt obtained by melt mixing is transported to the spinning unit to obtain raw silk. The raw silk is oiled, crimped and stretched to obtain polyester fiber.
[0034] In this case, the mass ratio of dried recycled polyester to epoxy chain extender in Example 1 was 100:1.5.
[0035] The waste polyester raw material is waste polyester cola bottles (intrinsic viscosity 0.58 g / dl).
[0036] The screw extruder has a screw diameter of 65mm and a length-to-diameter ratio of 30. It has five temperature zones with temperatures of 235℃, 250℃, 260℃, 265℃, and 265℃, respectively.
[0037] The main parameters of the spinning unit are: melt filter filtration accuracy 25μm, spinning box temperature 270℃, spinneret orifice number 40, spinneret orifice diameter 0.2mm, spinneret orifice length-to-diameter ratio 1, cooling air temperature 25℃, humidity 55%, air velocity 2m / min, and spinning speed 1500m / min.
[0038] Example 3 A method for preparing polyester fibers using waste polyester raw materials includes the following steps: (1) The waste polyester raw materials are sorted, cleaned, crushed and dried to obtain recycled polyester; (2) The recycled polyester is transported to a drying device and dried at 140°C for 30 min and at 170°C for 3 h. Then the dried recycled polyester and the epoxy chain extender of Preparation Example 1 are added to a screw extruder for melt mixing. The melt obtained by melt mixing is transported to the spinning unit to obtain raw silk. The raw silk is oiled, crimped and stretched to obtain polyester fiber.
[0039] In this case, the mass ratio of dried recycled polyester to epoxy chain extender in Example 1 was 100:3.
[0040] The waste polyester raw material is waste polyester cola bottles (intrinsic viscosity 0.58 g / dl).
[0041] The screw extruder has a screw diameter of 65mm and a length-to-diameter ratio of 30. It has five temperature zones with temperatures of 240℃, 260℃, 265℃, 270℃, and 270℃, respectively.
[0042] The main parameters of the spinning unit are: melt filter filtration accuracy 25μm, spinning box temperature 275℃, spinneret orifice number 48, spinneret orifice diameter 0.2mm, spinneret orifice length-to-diameter ratio 1.5, cooling air temperature 30℃, humidity 65%, air velocity 4m / min, and spinning speed 2500m / min.
[0043] Example 4 A method for preparing polyester fibers using waste polyester raw materials, which differs from Example 1 only in that the epoxy chain extender in Example 1 is replaced with an equal mass of the product obtained in Example 2.
[0044] Example 5 A method for preparing polyester fibers using waste polyester raw materials, which differs from Example 1 only in that the epoxy chain extender in Example 1 is replaced with an equal mass of the product obtained in Example 3.
[0045] Comparative Example 1 A method for preparing polyester fiber using waste polyester raw materials, which differs from Example 1 only in that the epoxy chain extender in Example 1 is replaced with an equal mass of bisoxazolinobenzene.
[0046] Comparative Example 2 A method for preparing polyester fiber using waste polyester raw materials, which differs from Example 1 only in that the epoxy chain extender in Example 1 is replaced with an equal mass of pyromellitic anhydride.
[0047] Comparative Example 3 A method for preparing polyester fibers using waste polyester raw materials, which differs from Example 1 only in that the epoxy chain extender in Example 1 is replaced with the same mass of the substance in Control Example 1.
[0048] The polyester fibers obtained in Examples 1-5 and Comparative Examples 1-3 were subjected to performance tests, and the test procedures are as follows: Breaking strength and breaking elongation: Using a fiber tensile tester, in accordance with GB / T 14337-2022 "Test Method for Tensile Properties of Chemical Fibers Short Fibers", the tension clamp and clamping length required by the standard are selected based on the nominal linear density of the fiber; 180℃ dry heat shrinkage rate: Using a single fiber heat shrinkage rate tester, in accordance with GB / T 43015-2023 "Test method for dry heat shrinkage rate of synthetic short fibers", the tension clamp required by the standard is selected according to the nominal linear density of the fiber. The change in fiber length before and after dry heat treatment in an oven at 180℃ for 30 min is tested. The instrument automatically generates a report and displays the 180℃ dry heat shrinkage rate. Dye uptake rate: Prepare two identical dye baths: cationic brilliant blue RL 0.5% (owf), leveling agent 1227 0.5% (owf), adjust the pH to 4.5 with acetic acid, add polyester fiber to one dye bath and not add it to the other, and use the same dyeing process until dyeing is completed. The dyeing process is as follows: liquor ratio 30:1, dyeing at 40℃, continuous dyeing under boiling for 60 minutes, after dyeing is completed, cool down to room temperature and take out the sample; Dilute the staining residue to 500 mL with distilled water, then transfer 20 mL to a 100 mL volumetric flask and dilute again to 100 mL with distilled water. max The absorbance B of the staining residue was measured at λ. The standard staining solution that had undergone the staining process was also diluted to 500 mL, and 5 mL was transferred to a 100 mL volumetric flask. This flask was then diluted to 100 mL with distilled water. max处 Measure the absorbance A of the standard dye solution, and then calculate the dyeing rate (%) using the following formula: Dyeing rate = 100% - X; X = [B / (Axn)x100%] Where: X - mass fraction of dye in dyeing residue (%); A - absorbance of standard dye; B - absorbance of dyeing residue; n - The multiple of the test concentration of the standard dye solution and the residual dye solution.
[0049] The test results are shown in Table 1: Table 1 project Fracture strength (cN / dtex) Elongation at break (%) Dry heat shrinkage rate at 180℃ (%) Dye uptake rate (%) Example 1 5.2 24.2 6.2 93.5 Example 2 5.9 25.3 6.0 94.1 Example 3 5.6 24.6 5.7 94.3 Example 4 5.1 24.0 6.3 93.4 Example 5 5.3 24.1 6.2 93.2 Comparative Example 1 4.6 19.8 8.4 62.4 Comparative Example 2 4.2 18.5 7.6 60.3 Comparative Example 3 3.6 15.2 8.6 71.2 Analyzing the data recorded in Table 1, the polyester fibers prepared in Examples 1-3 have a breaking strength ≥ 5.1 cN / dtex, a breaking elongation ≥ 24.0%, a dry heat shrinkage rate ≤ 6.3% at 180℃, and a dye uptake rate ≥ 93.2%. This indicates that the epoxy chain extender in this invention is a recycled polyester auxiliary agent that integrates "chain repair, toughening, reinforcement, flammability, and heat resistance," which not only realizes the secondary utilization of waste polyester but also endows the recycled polyester fibers with good performance characteristics.
[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing polyester fibers using waste polyester raw materials, characterized in that, Includes the following steps: Waste polyester raw materials are sorted, cleaned, crushed and dried to obtain recycled polyester; The recycled polyester is fed into a drying unit and dried at 120-140℃ for 10-30 minutes and at 140-170℃ for 3-6 hours. Then, the dried recycled polyester and epoxy chain extender are added to a screw extruder for melt mixing. The melt obtained from the melt mixing is fed into the spinning unit to obtain raw silk. The raw silk is then oiled, crimped, and drawn to obtain polyester fiber. The epoxy chain extender is prepared by a chemical reaction between sulfonic acid triazine phenol and epichlorohydrin. The molecular structure of the sulfonyl triazine phenol is as follows: 。 2. The method for preparing polyester fiber using waste polyester raw materials according to claim 1, characterized in that, The mass ratio of dried recycled polyester to epoxy chain extender is 100:0.5-3.
3. The method for preparing polyester fiber using waste polyester raw materials according to claim 1, characterized in that, The preparation process of the epoxy chain extender is as follows: Sulfonated triazine phenol, potassium hydroxide, and anhydrous ethanol were added sequentially to a flask and stirred for 3-5 minutes. Epichlorohydrin was then added, and the mixture was heated to 70°C under a nitrogen atmosphere and stirred for 4 hours. The temperature was then lowered to 20-30°C, and potassium hydroxide solution was added dropwise. After the addition was complete, the temperature was raised to 60°C, and the mixture was stirred for 6-8 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered, and the filtrate was evaporated to dryness to obtain the epoxy chain extender.
4. The method for preparing polyester fiber using waste polyester raw materials according to claim 3, characterized in that, The ratio of sulfonic acid triazine phenol, potassium hydroxide, anhydrous ethanol, epichlorohydrin and potassium hydroxide solution is 26.5-28g: 2.8g: 200-300mL: 9.25g: 8.42g, and the mass fraction of potassium hydroxide solution is 35-45%.
5. The method for preparing polyester fiber using waste polyester raw materials according to claim 1, characterized in that, The preparation process of the sulfonic acid triazine phenol is as follows: S1. Add cyanuric chloride to a flask containing acetone, cool to 0-5℃, and add potassium hydroxide aqueous solution containing aminoethanesulfonic acid dropwise while stirring. During the dropwise addition, maintain the pH of the system at 7-8 with 1mol / L potassium carbonate solution. After the dropwise addition is complete, stir the reaction for 12h. After the reaction is complete, filter to obtain potassium sulfonate dichlorotriazine. S2. Add potassium sulfonate dichlorotriazine to a flask containing deionized water. Under nitrogen protection, stir and heat to 20-25℃. Add an acetone solution of p-aminophenol dropwise. During the dropwise addition, maintain the pH of the system at 7-8 with 1 mol / L potassium carbonate solution. Stir the reaction for 12 hours. After the reaction is completed, remove the acetone by vacuum distillation to obtain the intermediate product. S3. Add 1,3-bis(3-aminopropyl)tetramethyldisiloxane and potassium carbonate to a flask containing anhydrous ethanol. Under nitrogen protection, stir and heat to 80-85°C. Add the aqueous solution of the intermediate product in three equal batches, with an interval of 2-3 min between each batch. Stir and react for 12 h. After the reaction is complete, remove the anhydrous ethanol by rotary evaporation. Wash the rotary evaporated product with ethyl acetate. Then concentrate, crystallize and dry the washed product to obtain sulfonic acid triazine phenol.
6. The method for preparing polyester fiber using waste polyester raw materials according to claim 5, characterized in that, The mass ratio of cyanuric chloride to taurine in S1 is 9.23:6.3-6.
8. The potassium hydroxide aqueous solution containing taurine is composed of taurine and 1 mol / L potassium hydroxide aqueous solution in a dosage ratio of 6.3-6.8 g:55 mL.
7. The method for preparing polyester fiber using waste polyester raw materials according to claim 5, characterized in that, The mass ratio of potassium sulfonate dichlorotriazine to p-aminophenol in S2 is 15.5-16.0:
6. The acetone solution of p-aminophenol is composed of p-aminophenol and acetone in a ratio of 6g:55mL.
8. A method for preparing polyester fiber from waste polyester raw materials according to claim 5, characterized in that, In S3, the mass ratio of 1,3-bis(3-aminopropyl)tetramethyldisiloxane, potassium carbonate, and intermediate product is 5.48 g: 5.5 g: 21.5-22 g. The aqueous solution of the intermediate product is composed of the intermediate product and deionized water in a ratio of 1 g: 10 mL.
9. The method for preparing polyester fiber using waste polyester raw materials according to claim 1, characterized in that, The screw extruder has a screw diameter of 65mm, a screw length-to-diameter ratio of 30, and five temperature zones, with temperatures of 235-240℃, 250-260℃, 260-265℃, 265-270℃, and 265-270℃ respectively.
10. A method for preparing polyester fiber from waste polyester raw materials according to claim 1, characterized in that, The main parameters of the spinning unit are as follows: melt filter filtration accuracy 25μm, spinning box temperature 270-275℃, spinneret orifice number 40-48, spinneret orifice diameter 0.2-0.4mm, spinneret orifice length-to-diameter ratio 1-1.5, cooling air temperature 25-30℃, humidity 55-65%, wind speed 2-4m / min, and spinning speed 1500-2500m / min.