High moisture-absorbing and low fuzzing and pilling regenerated polyester fiber and preparation of blended yarn thereof

Abstract

This invention discloses a highly absorbent, low-pilling recycled polyester fiber and the blended yarn prepared therefrom, belonging to the technical field of polyester fiber materials. It addresses the technical problem that the absorbency, mechanical strength, and anti-pilling properties of recycled polyester fibers and their blended yarns in the prior art need further improvement. The recycled polyester fiber comprises a recycled fiber matrix and a functionalized layer on the surface of the matrix. This invention involves introducing sodium isophthalic acid-5-sulfonate, adipic acid, and esterified polyether into the polyester backbone, which then interacts with epoxy activated particles. A hydrophilic interface layer rich in polar groups is formed on the fiber surface through dopamine coating and glycidyl ring-opening reaction. The recycled polyester fiber is then blended with modal fiber, effectively improving not only the absorbency, moisture diffusion, and evaporation properties of the blended yarn, but also its tensile properties and anti-pilling properties.

Description

Technical Field

[0001] This invention relates to the field of polyester fiber material technology, specifically to a highly absorbent, low-pilling recycled polyester fiber and the blended yarn prepared therefrom. Background Technology

[0002] Polyester fiber has been widely used in clothing, home textiles and industrial textiles due to its advantages such as high strength, good dimensional stability, excellent abrasion resistance, easy washing and quick drying and reasonable cost. As the main type of polyester fiber, polyester fiber occupies an important position in the textile industry. With the development of technology for recycling waste polyester products, recycled polyester fiber has become one of the important development directions in the field of chemical fibers because it can effectively realize the resource utilization of waste PET, reduce the consumption of petrochemical resources and reduce the environmental burden.

[0003] Currently, due to the low polarity and poor moisture absorption of polyester molecular chains, the fibers are prone to problems such as stuffiness, static electricity buildup, and insufficient comfort when worn, making it difficult to meet the requirements of modern textiles for moisture absorption, wicking, and wearing comfort. At the same time, during the recycling, cleaning, melting, and reprocessing of waste PET, oligomers, degradation byproducts, coloring impurities, and other pollutants are often introduced, leading to a decrease in the uniformity of the recycled polyester molecular structure, which in turn affects the mechanical properties, spinnability, and quality of the final product.

[0004] In terms of blended yarn preparation, although blending with natural fibers or regenerated cellulose fibers can improve the moisture absorption and comfort of polyester products to some extent, relying solely on simple blending often fails to fundamentally solve the problem of insufficient moisture absorption of the regenerated polyester itself. Moreover, regenerated polyester fibers and their blended products generally suffer from pilling and fuzzing problems during weaving and wearing, especially when there are micro-defects on the fiber surface, insufficient yarn cohesion, or increased friction between fibers, the fiber ends are more likely to escape from the yarn and entangle to form fuzz balls.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a highly absorbent, low-pilling recycled polyester fiber and the blended yarn prepared therefrom, in order to solve the technical problem that the wettability, mechanical strength and anti-pilling properties of recycled polyester fibers and the blended yarns prepared therefrom need to be further improved in the prior art.

[0007] The objective of this invention can be achieved through the following technical solution: a highly absorbent, low-pilling recycled polyester fiber, wherein the recycled polyester fiber comprises a recycled fiber matrix and a functionalized layer located on the surface of the recycled fiber matrix;

[0008] The regenerated fiber matrix comprises the following components by weight: 100 parts of wet-modified PET, 10-15 parts of epoxy activated particles, and 3-5 parts of additives;

[0009] The functionalized layer includes a polydopamine coating layer deposited on the surface of the regenerated fiber matrix, and a glycidyl open-ring hydrophilic layer grafted onto the polydopamine coating layer.

[0010] Furthermore, the wettability-modified PET is prepared by the following steps:

[0011] A1. Crush the waste polyester bottle flakes and mix them with the dissolving solution. Heat the reaction system to 110-120℃ and stir until the system is dissolved. Add impregnated alkali activated carbon to the reaction system and keep it at the temperature for 3-5 hours. Then perform post-treatment to obtain pretreated PET.

[0012] A2. Under an inert gas atmosphere, pretreated PET, sodium isophthalic acid-5-sulfonate, adipic acid, ethylene glycol, and catalyst are mixed. The reaction system is heated to 175-185℃ and kept at this temperature for 4-5 hours. Esterified polyether and antimony trioxide are added to the reaction system. The reaction system is then subjected to a negative pressure of -0.1MPa. The reaction system is heated to 235-245℃ and kept at this temperature for 2-3 hours. The material is discharged while hot to obtain wettability modified PET.

[0013] The synthesis reaction equation for hydrophilic modified PET is:

[0014]

[0015] In the formula, R is or or .

[0016] Further, in step A1, the ratio of the waste polyester bottle flakes, the dissolving solution, and the impregnated alkaline activated carbon is 10g:70-80mL:2-3g. The dissolving solution is composed of phenol and carbon tetrachloride in a volume ratio of 2:1. The post-treatment includes: after the reaction is complete, filtering while hot, cooling the filtrate to room temperature, adding anhydrous ethanol to the filtrate, stirring and dispersing for 30-50 minutes, filtering, washing the filter cake three times with anhydrous ethanol and drying it, transferring the filter cake to a drying oven at a temperature of 70-80℃, and drying it to constant weight to obtain pretreated PET.

[0017] Furthermore, in step A2, the weight ratio of the pretreated PET, sodium isophthalate-5-sulfonate, adipic acid, ethylene glycol, catalyst, esterified polyether, and antimony trioxide is 100:4-5:8-10:50-60:0.1:28-32:0.05, and the catalyst is zinc acetate.

[0018] Furthermore, the preparation method of alkali-impregnated activated carbon is as follows: the activated carbon and alkali solution are mixed, ultrasonically dispersed at room temperature for 20-30 minutes, filtered, the filter cake is washed three times with anhydrous ethanol and then dried, the filter cake is transferred to a drying oven at a temperature of 60-70℃ and dried to constant weight to obtain alkali-impregnated activated carbon.

[0019] Furthermore, the solid-liquid ratio of the activated carbon and the alkaline solution is 1:10, and the alkaline solution is an aqueous solution of potassium hydroxide with a concentration of 10-12 mol / L.

[0020] Furthermore, the preparation method of esterified polyether is as follows: under an inert gas atmosphere, polyethylene glycol, acetone and triethylamine are mixed, the reaction system is cooled to 3-5℃, acetyl chloride solution is added dropwise to the reaction system, the reaction is kept at the temperature for 60-80 min, the reaction system is naturally heated to room temperature, the reaction is kept at the temperature for 3-5 h, and then post-processed to obtain esterified polyether.

[0021] The synthesis reaction formula for esterified polyether is as follows:

[0022]

[0023] Furthermore, the ratio of polyethylene glycol, acetone, triethylamine, and acetyl chloride solution is 10g:50mL:1.2-1.3g:14-15g, the acetyl chloride solution is composed of acetyl chloride and acetone in a weight ratio of 1:5, the polyethylene glycol is PEG-800, and the post-treatment includes: after the reaction is complete, the reaction system is heated to 60°C, and low-boiling substances are removed by vacuum evaporation to obtain esterified polyether.

[0024] Furthermore, the preparation method of epoxy activated particles is as follows: diatomaceous earth, anhydrous ethanol and KH-560 are mixed, the reaction system is heated to 55-65℃, sodium hydroxide solution is added to the reaction system, the reaction is kept at the temperature for 40-60 min, and then post-processed to obtain epoxy activated particles.

[0025] Furthermore, the ratio of diatomaceous earth, anhydrous ethanol, KH-560, and sodium hydroxide solution is 7g:70mL:2.3-2.7g:6-8mL, and the concentration of sodium hydroxide solution is 2-3mol / L. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at 70-80℃ and dried to constant weight to obtain epoxy activated particles.

[0026] Furthermore, the regenerated fiber matrix is ​​obtained through the following steps:

[0027] Wet-modified PET, epoxy activated particles, and additives are mixed and placed in a drying oven at 95-105℃ and dried until the moisture content is below 30ppm to obtain pretreated dried material.

[0028] The pretreated and dried material was added to a twin-screw extruder. The temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end were set to 255℃, 260℃, 260℃, 265℃, and 265℃ respectively, and the die temperature was set to 270℃. After melting and mixing for 3 minutes, the mixture was filtered through a 40-mesh sieve and melt-extruded into a melt spinning machine. The melt spinning temperature was set to 288℃, and the fibers were spun out through a spinneret with an aperture of 0.2mm and an aspect ratio of 3:1. The spinning speed was set to 600m / min, and the spinning was cooled by air with a temperature of 18℃, a humidity of 75%, and an air velocity of 0.6m / s to obtain crude regenerated fiber.

[0029] The recycled fiber crude product is hot-stretched at a temperature of 110-130℃ with a stretching ratio of 5-7 times to obtain the recycled fiber matrix.

[0030] Furthermore, the functionalized layer is prepared by the following steps:

[0031] B1. Mix dopamine hydrochloride and buffer solution and stir until the system is dissolved. At room temperature, add regenerated fiber matrix to the reaction system, keep warm and impregnate for 30-50 minutes, and then perform post-treatment to obtain dopamine-coated polyester fiber.

[0032] B2. Mix dopamine-coated fiber, glycidol, ethanol and alkali solution and sonicate. Heat the reaction system to 60-70℃ and keep it at that temperature for 3-5 hours. After post-treatment, a functionalized layer is formed on the outside of the regenerated fiber matrix to obtain regenerated polyester fiber.

[0033] Further, in step B1, the ratio of dopamine hydrochloride, buffer solution, and crude regenerated polyester fiber is 2g:1L:10-13g, the buffer solution is a 0.5mol / L Tris buffer solution with pH=8.5, and the post-treatment includes: after the reaction is complete, the fiber is taken out of the solution, washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at a temperature of 60-70℃ and dried to constant weight to obtain dopamine-coated polyester fiber.

[0034] Further, in step B2, the ratio of dopamine-coated fiber, glycidyl ether, ethanol, and alkali solution is 10g:1.3-1.8g:100mL:30mL, and the alkali solution is a 0.1-0.3mol / L sodium hydroxide aqueous solution. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at a temperature of 60-70℃ and dried to constant weight to obtain recycled polyester fiber.

[0035] The present invention also proposes a blended yarn prepared from highly absorbent, low-pilling recycled polyester fiber, which, by weight, comprises 60-70 parts of highly absorbent, low-pilling recycled polyester fiber and 25-30 parts of modal fiber.

[0036] The present invention has the following beneficial effects:

[0037] 1. This invention utilizes impregnated alkaline activated carbon to deeply adsorb and remove oligomers, acidic degradation byproducts, coloring impurities, and polar pollutants from the waste PET dissolution system, thereby effectively improving the purity and reaction uniformity of recycled polyester raw materials and reducing the risk of side reactions and thermal degradation during subsequent polycondensation. Then, sodium isophthalic acid-5-sulfonate, adipic acid, and esterified polyether are used in the transesterification and polycondensation reactions, synergistically introducing ionic hydrophilic groups, flexible aliphatic segments, and polyether hydrophilic segments into the polyester backbone. The sodium sulfonate groups provide stable polar water absorption sites, the polyether segments enhance the transfer and diffusion of water molecules within the material, and the adipic acid reduces segment rigidity, improves chain structure regularity and balanced crystallization behavior, promoting a more uniform distribution of the hydrophilic structure in the polyester matrix and alleviating the increased brittleness often associated with hydrophilic modification. This improves the hygroscopicity of polyester fibers while simultaneously increasing the breaking strength and elongation at break of the recycled fibers.

[0038] 2. This invention also uses KH-560 to epoxidize and activate diatomaceous earth, forming a functional interface on its surface that combines an organic phase compatibility layer and reactive epoxy groups. During melt blending and spinning, it undergoes ring-opening reactions with the carboxyl and hydroxyl groups at the ends of the polyester chains or forms strong interfacial bonds, significantly improving the dispersion and bonding strength of inorganic particles in the polyester matrix. This avoids the strength reduction and frictional detachment caused by agglomeration and interfacial debonding of ordinary fillers. Moreover, the porous structure and high specific surface area retained by diatomaceous earth can form a moisture-absorbing layer inside the fiber and promote capillary transfer. The microscopic channels are guided; dopamine self-polymerizes to form a polydopamine coating rich in phenolic hydroxyl and amine groups on the fiber surface, and then glycidol is used to perform ring-opening grafting under alkaline conditions to construct a stable polyhydroxy hydrophilic layer on the fiber surface. While significantly accelerating the wetting, spreading and diffusion process of water droplets on the fiber surface, it can passivate and cover micro-defects and friction-sensitive sites on the fiber surface, reduce the probability of the end of the single fiber being hooked out, entangled and forming a fuzz ball under external friction, and simultaneously improve the moisture absorption, moisture wicking, quick drying and low pilling performance of the regenerated fiber.

[0039] 3. This invention also involves blending recycled polyester fibers with modal fibers to prepare blended yarns. Modal fibers themselves have high hygroscopicity, good softness, and a relatively smooth surface morphology. When combined with recycled polyester fibers, they can further improve the absorption and transfer efficiency of moisture in the yarn and fabric, forming a continuous pathway for moisture absorption, rapid surface wetting, and yarn-level moisture conduction. This allows moisture to quickly diffuse from the contact point to the surrounding area and form a large evaporation surface, achieving not only a high water absorption rate, a short drip diffusion time, and a fast drying rate, but also, the good cohesion and low surface hairiness of modal fibers can form a more stable and uniform yarn structure with the surface-modified recycled polyester fibers of this invention, reducing fiber end exposure and friction entanglement during fabric use, thereby improving the pilling and fuzzing level. Detailed Implementation

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[0041] In this application, the polyethylene glycol is PEG-800;

[0042] In this application, the modal fiber has a fineness of 1.0 dtex and a length of 34-38 mm;

[0043] In this application, the diatomaceous earth has a particle size of 20-50 nm and a content of 98%.

[0044] In this application, KH-560 is γ-glycidyl etheroxypropyltrimethoxysilane, CAS number 2530-83-8.

[0045] Example 1

[0046] This embodiment provides a method for preparing wettable modified PET, specifically including the following steps:

[0047] Step 1: Preparation of pretreated PET

[0048] Activated carbon and 10 mol / L potassium hydroxide aqueous solution were added to a reaction flask at a solid-liquid ratio of 1:10 and mixed. The mixture was ultrasonically dispersed at room temperature for 20 min, filtered, and the filter cake was washed three times with anhydrous ethanol and then dried under vacuum. The filter cake was transferred to a drying oven at 60℃ and dried to constant weight to obtain alkali-impregnated activated carbon.

[0049] Waste polyester bottle flakes are washed, crushed, and passed through a 20-mesh sieve to obtain waste polyester powder.

[0050] Phenol and carbon tetrachloride were mixed evenly at a volume ratio of 2:1 to obtain a solution;

[0051] Weigh 500g of waste polyester powder and 3500mL of dissolving solution and add them to a reaction flask. Heat the reaction flask to 110℃ and stir until the system is dissolved. Add 100g of alkali-impregnated activated carbon to the reaction flask and keep it at this temperature for 3 hours. Filter while hot. Cool the filtrate to room temperature and add 8L of anhydrous ethanol to the filtrate. Stir and disperse for 30 minutes. Filter again. Wash the filter cake three times with anhydrous ethanol and dry it. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain pretreated PET.

[0052] Step 2: Preparation of esterified polyether

[0053] Acetyl chloride and acetone were mixed evenly at a weight ratio of 1:5 to obtain an acetyl chloride solution;

[0054] Weigh out 200g of polyethylene glycol, 1000mL of acetone, and 24g of triethylamine and add them to an argon-protected reaction flask. Stir the mixture and cool the reaction flask to 3°C. Add 240g of acetyl chloride solution to the reaction flask and keep it at this temperature for 60min. Then, allow the reaction flask to naturally warm to room temperature and keep it at this temperature for 3h. Finally, heat the reaction flask to 60°C and remove low-boiling-point substances by vacuum distillation to obtain esterified polyether.

[0055] Step 3: Preparation of wettophilic modified PET

[0056] Weigh out 500g of pretreated PET, 20g of sodium isophthalic acid-5-sulfonate, 40g of adipic acid, 250g of ethylene glycol, and 0.5g of zinc acetate catalyst, and add them to an argon-protected reaction flask. Stir the mixture and heat it to 175℃. Keep the temperature for 4 hours. Add 140g of esterified polyether and 0.25g of antimony trioxide to the reaction flask. Apply a negative pressure of -0.1MPa to the reaction flask and heat it to 235℃. Keep the temperature for 2 hours. Discharge the mixture while it is still hot. After cooling and curing, slice the mixture to a thickness of 0.1mm to obtain the wettability modified PET.

[0057] Example 2

[0058] This embodiment provides a method for preparing wettable modified PET, specifically including the following steps:

[0059] Step 1: Preparation of pretreated PET

[0060] Activated carbon and 11 mol / L potassium hydroxide aqueous solution were added to a reaction flask at a solid-liquid ratio of 1:10 and mixed. The mixture was ultrasonically dispersed at room temperature for 25 min, filtered, and the filter cake was washed three times with anhydrous ethanol and then dried under vacuum. The filter cake was transferred to a drying oven at 65℃ and dried to constant weight to obtain alkali-impregnated activated carbon.

[0061] Waste polyester bottle flakes are washed, crushed, and passed through a 20-mesh sieve to obtain waste polyester powder.

[0062] Phenol and carbon tetrachloride were mixed evenly at a volume ratio of 2:1 to obtain a solution;

[0063] Weigh 500g of waste polyester powder and 3750mL of dissolving solution into a reaction flask and mix. Heat the reaction flask to 115℃ and stir until the system is dissolved. Add 125g of alkali-impregnated activated carbon to the reaction flask and keep it at this temperature for 4 hours. Filter while hot. Cool the filtrate to room temperature and add 8L of anhydrous ethanol to the filtrate. Stir and disperse for 40 minutes. Filter again. Wash the filter cake three times with anhydrous ethanol and dry it. Transfer the filter cake to a drying oven at 75℃ and dry it to constant weight to obtain pretreated PET.

[0064] Step 2: Preparation of esterified polyether

[0065] Acetyl chloride and acetone were mixed evenly at a weight ratio of 1:5 to obtain an acetyl chloride solution;

[0066] Weigh out 200g of polyethylene glycol, 1000mL of acetone, and 25g of triethylamine and add them to an argon-protected reaction flask. Stir the mixture and cool the reaction flask to 4°C. Add 270g of acetyl chloride solution to the reaction flask and keep it at this temperature for 70min. Then, allow the reaction flask to naturally warm to room temperature and keep it at this temperature for 4h. Finally, heat the reaction flask to 60°C and remove low-boiling-point substances by vacuum distillation to obtain esterified polyether.

[0067] Step 3: Preparation of wettophilic modified PET

[0068] Weigh out 500g of pretreated PET, 23g of sodium isophthalic acid-5-sulfonate, 45g of adipic acid, 275g of ethylene glycol, and 0.5g of zinc acetate catalyst, and add them to an argon-protected reaction flask. Stir the mixture and heat the flask to 180℃. Maintain the temperature for 4.5h. Add 150g of esterified polyether and 0.25g of antimony trioxide to the reaction flask. Apply a negative pressure of -0.1MPa to the reaction flask and heat it to 240℃. Maintain the temperature for 2.5h. Discharge the mixture while it is still hot. After cooling and curing, slice the mixture to a thickness of 0.15mm to obtain the wettability modified PET.

[0069] Example 3

[0070] This embodiment provides a method for preparing wettable modified PET, specifically including the following steps:

[0071] Step 1: Preparation of pretreated PET

[0072] Activated carbon and 12 mol / L potassium hydroxide aqueous solution were added to a reaction flask at a solid-liquid ratio of 1:10 and mixed. The mixture was ultrasonically dispersed at room temperature for 30 min, filtered, and the filter cake was washed three times with anhydrous ethanol and then dried under vacuum. The filter cake was transferred to a drying oven at 70℃ and dried to constant weight to obtain alkali-impregnated activated carbon.

[0073] Waste polyester bottle flakes are washed, crushed, and passed through a 20-mesh sieve to obtain waste polyester powder.

[0074] Phenol and carbon tetrachloride were mixed evenly at a volume ratio of 2:1 to obtain a solution;

[0075] Weigh 500g of waste polyester powder and 4000mL of dissolving solution and add them to a reaction flask. Heat the reaction flask to 120℃ and stir until the system is dissolved. Add 150g of alkali-impregnated activated carbon to the reaction flask and keep it at this temperature for 5 hours. Filter while hot. Cool the filtrate to room temperature and add 8L of anhydrous ethanol to the filtrate. Stir and disperse for 50 minutes. Filter again. Wash the filter cake three times with anhydrous ethanol and dry it. Transfer the filter cake to a drying oven at 80℃ and dry it to constant weight to obtain pretreated PET.

[0076] Step 2: Preparation of esterified polyether

[0077] Acetyl chloride and acetone were mixed evenly at a weight ratio of 1:5 to obtain an acetyl chloride solution;

[0078] Weigh out 200g of polyethylene glycol, 1000mL of acetone, and 26g of triethylamine and add them to an argon-protected reaction flask. Stir the mixture and cool the reaction flask to 5°C. Add 300g of acetyl chloride solution to the reaction flask and keep it at this temperature for 80min. Then, allow the reaction flask to naturally warm to room temperature and keep it at this temperature for 5h. Finally, heat the reaction flask to 60°C and remove low-boiling-point substances by vacuum distillation to obtain esterified polyether.

[0079] Step 3: Preparation of wettophilic modified PET

[0080] Weigh out 500g of pretreated PET, 25g of sodium isophthalic acid-5-sulfonate, 50g of adipic acid, 300g of ethylene glycol, and 0.5g of zinc acetate catalyst, and add them to an argon-protected reaction flask. Stir the mixture and heat the flask to 185℃. Maintain the temperature for 5 hours. Add 160g of esterified polyether and 0.25g of antimony trioxide to the reaction flask. Apply a negative pressure of -0.1MPa to the reaction flask and heat it to 245℃. Maintain the temperature for 3 hours. Discharge the mixture while it is still hot. After cooling and curing, slice the mixture to a thickness of 0.2mm to obtain the wettability modified PET.

[0081] Example 4

[0082] This embodiment provides a method for preparing highly absorbent, low-pilling, recycled polyester fiber, including the following steps:

[0083] Step I: Preparation of epoxy activated particles

[0084] Weigh out 70g of diatomaceous earth, 700mL of anhydrous ethanol and 23g of KH-560 and add them to the reaction flask. Stir the mixture and heat the reaction flask to 55℃. Add 60mL of 2mol / L sodium hydroxide solution to the reaction flask and keep it at this temperature for 40min. Cool the reaction flask to room temperature and filter it. Wash the filter cake with purified water until it is neutral and then dry it. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain epoxy activated particles.

[0085] Step II: Preparation of regenerated fiber matrix

[0086] Zinc stearate, ethylene bis-stearamide, triphenyl phosphite, antioxidant 1010, and antistatic agent SN are mixed evenly in a weight ratio of 6:4:3:2:2 to obtain the additives.

[0087] Weigh out the following by weight: 100 parts of the wettable modified PET prepared in Example 1, 10 parts of epoxy activated particles, and 3 parts of additives. Mix them together and place them in a drying oven at 95°C. Dry them until the moisture content is less than 30 ppm to obtain the pretreated dried material.

[0088] The pretreated and dried material was added to a twin-screw extruder. The temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end were set to 255℃, 260℃, 260℃, 265℃, and 265℃ respectively, and the die temperature was set to 270℃. After melting and mixing for 3 minutes, the mixture was filtered through a 40-mesh sieve and melt-extruded into a melt spinning machine. The melt spinning temperature was set to 288℃, and the fibers were spun out through a spinneret with an aperture of 0.2mm and an aspect ratio of 3:1. The spinning speed was set to 600m / min, and the spinning was cooled by air with a temperature of 18℃, a humidity of 75%, and an air velocity of 0.6m / s to obtain crude regenerated fiber.

[0089] The recycled fiber crude product was hot-stretched at a temperature of 110℃ with a stretching ratio of 5 times to obtain a recycled fiber matrix with a fineness of 2dtex.

[0090] Step III: Preparation of dopamine-coated polyester fibers

[0091] Weigh out 20g of dopamine hydrochloride and 20L of 0.5mol / L Tris buffer solution (pH=8.5), mix and stir until dissolved. Immerse 100g of regenerated fiber matrix in the solution at room temperature for 30min. Remove the fiber from the solution, wash with purified water until neutral, and then dry. Transfer the filter cake to a drying oven at 60℃ and dry to constant weight to obtain dopamine-coated polyester fiber.

[0092] Step IV: Preparation of recycled polyester fibers

[0093] Weigh out 100g of dopamine-coated fiber, 13g of glycidyl ether, 1000mL of ethanol and 300mL of 0.1mol / L sodium hydroxide aqueous solution and add them to a reaction flask. Mix the mixture, heat the reaction flask to 60℃, and ultrasonically disperse for 3h. Cool the reaction flask to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Transfer the filter cake to a drying oven at 60℃ and dry it to constant weight to obtain recycled polyester fiber.

[0094] Example 5

[0095] This embodiment provides a method for preparing highly absorbent, low-pilling, recycled polyester fiber, including the following steps:

[0096] Step I: Preparation of epoxy activated particles

[0097] Weigh out 70g of diatomaceous earth, 700mL of anhydrous ethanol and 25g of KH-560 and add them to the reaction flask. Stir the mixture and heat the reaction flask to 60℃. Add 70mL of 2.5mol / L sodium hydroxide solution to the reaction flask and keep it at this temperature for 50min. Cool the reaction flask to room temperature, filter it, wash the filter cake with purified water until neutral, and then dry it. Transfer the filter cake to a drying oven at 75℃ and dry it to constant weight to obtain epoxy activated particles.

[0098] Step II: Preparation of regenerated fiber matrix

[0099] Zinc stearate, ethylene bis-stearamide, triphenyl phosphite, antioxidant 1010, and antistatic agent SN are mixed evenly in a weight ratio of 6:4:3:2:2 to obtain the additives.

[0100] Weigh out the following by weight: 100 parts of the wettable modified PET prepared in Example 2, 13 parts of epoxy activated particles, and 4 parts of additives. Mix them together and place them in a drying oven at 100°C. Dry them until the moisture content is less than 30 ppm to obtain the pretreated dried material.

[0101] The pretreated and dried material was added to a twin-screw extruder. The temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end were set to 255℃, 260℃, 260℃, 265℃, and 265℃ respectively, and the die temperature was set to 270℃. After melting and mixing for 3 minutes, the mixture was filtered through a 40-mesh sieve and melt-extruded into a melt spinning machine. The melt spinning temperature was set to 288℃, and the fibers were spun out through a spinneret with an aperture of 0.2mm and an aspect ratio of 3:1. The spinning speed was set to 600m / min, and the spinning was cooled by air with a temperature of 18℃, a humidity of 75%, and an air velocity of 0.6m / s to obtain crude regenerated fiber.

[0102] The crude regenerated fiber was thermally stretched at 120°C with a stretching ratio of 6 times to obtain a regenerated fiber matrix with a fineness of 1.75 dtex.

[0103] Step III: Preparation of dopamine-coated polyester fibers

[0104] Weigh out 20g of dopamine hydrochloride and 20L of 0.5mol / L Tris buffer solution (pH=8.5), mix and stir until dissolved. Immerse 115g of regenerated fiber matrix in the solution at room temperature for 40min. Remove the fiber from the solution, wash with purified water until neutral, and then dry. Transfer the filter cake to a drying oven at 65℃ and dry to constant weight to obtain dopamine-coated polyester fiber.

[0105] Step IV: Preparation of recycled polyester fibers

[0106] Weigh out 100g of dopamine-coated fiber, 15.5g of glycidyl ether, 1000mL of ethanol and 300mL of 0.2mol / L sodium hydroxide aqueous solution and add them to the reaction flask. Mix the mixture, heat the reaction flask to 65℃, and ultrasonically disperse for 4h. Cool the reaction flask to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Transfer the filter cake to a drying oven at 65℃ and dry it to constant weight to obtain recycled polyester fiber.

[0107] Example 6

[0108] This embodiment provides a method for preparing highly absorbent, low-pilling, recycled polyester fiber, including the following steps:

[0109] Step I: Preparation of epoxy activated particles

[0110] Weigh out 70g of diatomaceous earth, 700mL of anhydrous ethanol and 27g of KH-560 and add them to the reaction flask. Stir the mixture and heat the reaction flask to 65℃. Add 80mL of 3mol / L sodium hydroxide solution to the reaction flask and keep it at this temperature for 60min. Cool the reaction flask to room temperature and filter it. Wash the filter cake with purified water until it is neutral and then dry it. Transfer the filter cake to a drying oven at 80℃ and dry it to constant weight to obtain epoxy activated particles.

[0111] Step II: Preparation of regenerated fiber matrix

[0112] Zinc stearate, ethylene bis-stearamide, triphenyl phosphite, antioxidant 1010, and antistatic agent SN are mixed evenly in a weight ratio of 6:4:3:2:2 to obtain the additives.

[0113] Weigh out the following by weight: 100 parts of the wettable modified PET prepared in Example 3, 15 parts of epoxy activated particles, and 5 parts of additives. Mix them together and place them in a drying oven at 105°C. Dry them until the moisture content is less than 30 ppm to obtain the pretreated dried material.

[0114] The pretreated and dried material was added to a twin-screw extruder. The temperatures of the five temperature zones of the twin-screw extruder from the feed end to the discharge end were set to 255℃, 260℃, 260℃, 265℃, and 265℃ respectively, and the die temperature was set to 270℃. After melting and mixing for 3 minutes, the mixture was filtered through a 40-mesh sieve and melt-extruded into a melt spinning machine. The melt spinning temperature was set to 288℃, and the fibers were spun out through a spinneret with an aperture of 0.2mm and an aspect ratio of 3:1. The spinning speed was set to 600m / min, and the spinning was cooled by air with a temperature of 18℃, a humidity of 75%, and an air velocity of 0.6m / s to obtain crude regenerated fiber.

[0115] The crude regenerated fiber was thermally stretched at 130°C with a stretching ratio of 7 times to obtain a regenerated fiber matrix with a fineness of 1.5 dtex.

[0116] Step III: Preparation of dopamine-coated polyester fibers

[0117] Weigh out 20g of dopamine hydrochloride and 20L of 0.5mol / L Tris buffer solution (pH=8.5), mix and stir until dissolved. Immerse 130g of regenerated fiber matrix in the solution at room temperature for 50min. Remove the fiber from the solution, wash with purified water until neutral, and then dry. Transfer the filter cake to a drying oven at 70℃ and dry to constant weight to obtain dopamine-coated polyester fiber.

[0118] Step IV: Preparation of recycled polyester fibers

[0119] Weigh out 100g of dopamine-coated fiber, 18g of glycidyl ether, 1000mL of ethanol and 300mL of 0.3mol / L sodium hydroxide aqueous solution and add them to a reaction flask. Mix the mixture, heat the reaction flask to 70℃, and ultrasonically disperse for 5h. Cool the reaction flask to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain recycled polyester fiber.

[0120] Example 7

[0121] This embodiment provides a blended yarn prepared from highly absorbent, low-pilling recycled polyester fiber, which, by weight, comprises: 60 parts of recycled polyester fiber prepared in Example 4 and 25 parts of modal fiber, with a linear density of 25±0.5 tex.

[0122] Example 8

[0123] This embodiment provides a blended yarn prepared from highly absorbent, low-pilling recycled polyester fiber, which, by weight, comprises: 65 parts of recycled polyester fiber prepared in Example 5 and 27 parts of modal fiber, with a linear density of 25±0.5 tex.

[0124] Example 9

[0125] This embodiment provides a blended yarn prepared from highly absorbent, low-pilling recycled polyester fiber, which, by weight, comprises: 70 parts of recycled polyester fiber prepared in Example 6 and 30 parts of modal fiber, with a linear density of 25±0.5 tex.

[0126] Comparative Example 1

[0127] The difference between this comparative example and Example 9 is that, in the preparation of the recycled polyester fiber used in this invention, activated carbon is used instead of the impregnated alkali activated carbon used in step 1 to prepare the pretreated PET.

[0128] Comparative Example 2

[0129] The difference between this comparative example and Example 9 is that, in the preparation of the recycled polyester fiber used in this invention, adipic acid was not added during the preparation of the wet-modified PET.

[0130] Comparative Example 3

[0131] The difference between this comparative example and Example 9 is that, in the preparation of the recycled polyester fiber used in this invention, no esterified polyether was added during the preparation of the wet-modified PET.

[0132] Comparative Example 4

[0133] The difference between this comparative example and Example 9 is that, in the preparation of the recycled polyester fiber used in this invention, steps III-IV are omitted, and the prepared recycled fiber matrix is ​​used instead of the recycled polyester fiber.

[0134] Comparative Example 5

[0135] The difference between this comparative example and Example 9 is that cotton fibers are used instead of modal fibers.

[0136] Performance testing:

[0137] The breaking strength and elongation at break of the blended yarn samples prepared in Examples 7-9 and Comparative Examples 1-5 were determined in accordance with the standard GB / T 3916-2013 "Determination of breaking strength and elongation at break of single yarn in packaged textiles (CRE method)".

[0138] The blended yarn samples prepared in Examples 7-9 and Comparative Examples 1-5 were woven using a circular loom to prepare textile fabric samples with a warp density of 120 ends / 10cm and a weft density of 95 ends / 10cm.

[0139] The water absorption rate, water droplet diffusion time (s), and drying rate (g / h) of textile fabric samples were determined in accordance with the standard GB / T 21655.1-2023 "Evaluation of moisture absorption and quick-drying properties of textiles - Part 1: Single combination test method".

[0140] According to the standard GB / T 4802.1-2008 "Textiles - Determination of pilling properties of fabrics - Part 1: Circular trajectory method", a pressure of 490cN was applied to the sample for testing. After the test, the pilling rating of the sample was evaluated. The specific test data are shown in Table 1 below.

[0141] Table 1 - Performance Test Data of Samples

[0142]

[0143] Performance testing:

[0144] Comparative analysis of the data in Table 1 shows that the tensile strength prepared by this invention reaches 23.2-23.6 cN / tex, the elongation at break reaches 16.5-16.9%, the water absorption rate of the prepared textile fabric sample reaches 209-215%, the water droplet diffusion time is reduced to 1.02-1.08 s, the drying rate reaches 2.28-2.35 g / h, and the pilling rating reaches 4.5. All performance test data are superior to the comparative example, indicating that this invention purifies waste PET by impregnating it with alkaline activated carbon to prepare pretreated PET, and through the use of isophthalic acid- Sodium 5-sulfonate, adipic acid, and esterified polyether are synergistically introduced into the polyester backbone, endowing recycled polyester with stable hygroscopic properties and good mechanical properties. Diatomaceous earth activated by KH-560 constructs a moisture-wicking microstructure inside the fiber, and forms a hydrophilic interface layer rich in polar groups on the fiber surface through dopamine coating and glycidyl ring-opening reaction, thereby enhancing the fiber's moisture absorption, diffusion, quick-drying, and anti-friction properties. Then, the recycled polyester fiber is blended with modal fiber, which not only effectively improves the hygroscopicity, moisture diffusion and evaporation properties of the blended yarn, but also improves the tensile properties and anti-pilling properties of the blended yarn.

[0145] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A highly absorbent, low-pilling, recycled polyester fiber, characterized in that, The recycled polyester fiber includes a recycled fiber matrix and a functionalized layer located on the surface of the recycled fiber matrix; The regenerated fiber matrix comprises the following components by weight: 100 parts of wet-modified PET, 10-15 parts of epoxy activated particles, and 3-5 parts of additives; The functionalized layer includes a polydopamine coating layer deposited on the surface of the regenerated fiber matrix, and a glycidyl open-ring hydrophilic layer grafted onto the polydopamine coating layer.

2. The highly absorbent, low-pilling, recycled polyester fiber according to claim 1, characterized in that, The wettability-modified PET is prepared by the following steps: A1. Crush the waste polyester bottle flakes and mix them with the dissolving solution. Heat the reaction system to 110-120℃ and stir until the system is dissolved. Add impregnated alkali activated carbon to the reaction system and keep it at the temperature for 3-5 hours. Then perform post-treatment to obtain pretreated PET. A2. Under an inert gas atmosphere, pretreated PET, sodium isophthalic acid-5-sulfonate, adipic acid, ethylene glycol, and catalyst are mixed. The reaction system is heated to 175-185℃ and kept at this temperature for 4-5 hours. Esterified polyether and antimony trioxide are added to the reaction system. The reaction system is then subjected to a negative pressure of -0.1MPa. The reaction system is heated to 235-245℃ and kept at this temperature for 2-3 hours. The material is discharged while hot to obtain wettability modified PET.

3. The highly absorbent, low-pilling, recycled polyester fiber according to claim 2, characterized in that, In step A1, the ratio of waste polyester bottle flakes, dissolving solution, and impregnated alkaline activated carbon is 10g:70-80mL:2-3g. The dissolving solution is composed of phenol and carbon tetrachloride in a volume ratio of 2:

1. The post-treatment includes: after the reaction is complete, hot filtration is performed, the filtrate is cooled to room temperature, anhydrous ethanol is added to the filtrate, and the mixture is stirred and dispersed for 30-50 minutes. The mixture is then filtered, the filter cake is washed three times with anhydrous ethanol, and then dried. The filter cake is transferred to a drying oven at 70-80℃ and dried to constant weight to obtain pretreated PET. In step A2, the weight ratio of pretreated PET, sodium isophthalate-5-sulfonate, adipic acid, ethylene glycol, catalyst, esterified polyether, and antimony trioxide is 100:4-5:8-10:50-60:0.1:28-32:0.

05. The catalyst is zinc acetate.

4. The highly absorbent, low-pilling, recycled polyester fiber according to claim 2, characterized in that, The preparation method of esterified polyether is as follows: under an inert gas atmosphere, polyethylene glycol, acetone and triethylamine are mixed, the reaction system is cooled to 3-5℃, acetyl chloride solution is added dropwise to the reaction system, the reaction is kept at the temperature for 60-80 min, the reaction system is naturally heated to room temperature, the reaction is kept at the temperature for 3-5 h, and then post-processed to obtain esterified polyether.

5. The highly absorbent, low-pilling, recycled polyester fiber according to claim 4, characterized in that, The ratio of polyethylene glycol, acetone, triethylamine, and acetyl chloride solution is 10g:50mL:1.2-1.3g:14-15g. The acetyl chloride solution is composed of acetyl chloride and acetone in a weight ratio of 1:

5. The polyethylene glycol is PEG-800. The post-treatment includes: after the reaction is complete, the reaction system is heated to 60°C, and low-boiling substances are removed by vacuum evaporation to obtain esterified polyether.

6. The highly absorbent, low-pilling, recycled polyester fiber according to claim 1, characterized in that, The preparation method of epoxy activated particles is as follows: diatomaceous earth, anhydrous ethanol and KH-560 are mixed, the reaction system is heated to 55-65℃, sodium hydroxide solution is added to the reaction system, the reaction is kept at the temperature for 40-60 min, and then post-processed to obtain epoxy activated particles.

7. The highly absorbent, low-pilling, recycled polyester fiber according to claim 6, characterized in that, The ratio of diatomaceous earth, anhydrous ethanol, KH-560, and sodium hydroxide solution is 7g:70mL:2.3-2.7g:6-8mL, and the concentration of sodium hydroxide solution is 2-3mol / L. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral, dried, and the filter cake is transferred to a drying oven at 70-80℃ and dried to constant weight to obtain epoxy activated particles.

8. The highly absorbent, low-pilling, recycled polyester fiber according to claim 1, characterized in that, The functionalized layer is prepared by the following steps: B1. Mix dopamine hydrochloride and buffer solution and stir until the system is dissolved. At room temperature, add regenerated fiber matrix to the reaction system, keep warm and impregnate for 30-50 minutes, and then perform post-treatment to obtain dopamine-coated polyester fiber. B2. Mix dopamine-coated fiber, glycidol, ethanol and alkali solution and sonicate. Heat the reaction system to 60-70℃ and keep it at that temperature for 3-5 hours. After post-treatment, a functionalized layer is formed on the outside of the regenerated fiber matrix to obtain regenerated polyester fiber.

9. The highly absorbent, low-pilling, recycled polyester fiber according to claim 8, characterized in that, In step B1, the ratio of dopamine hydrochloride, buffer solution, and crude regenerated polyester fiber is 2g:1L:10-13g. The buffer solution is a 0.5mol / L Tris buffer solution with pH=8.

5. The post-treatment includes: after the reaction is complete, the fiber is taken out of the solution, washed with purified water until neutral, and then dried. The filter cake is transferred to a drying oven at 60-70℃ and dried to constant weight to obtain dopamine-coated polyester fiber. In step B2, the ratio of dopamine-coated fiber, glycidyl ether, ethanol, and alkaline solution is 10g:1.3-1.8g:100mL:30mL. The alkaline solution is a 0.1-0.3mol / L sodium hydroxide aqueous solution. The post-treatment includes: after the reaction is complete, the reaction system is cooled to room temperature, filtered, the filter cake is washed with purified water until neutral, and then dried. The filter cake is transferred to a drying oven at 60-70℃ and dried to constant weight to obtain regenerated polyester fiber.

10. A blended yarn made from highly absorbent, low-pilling recycled polyester fiber, characterized in that, By weight, it includes 60-70 parts of highly absorbent, low-pilling recycled polyester fiber and 25-30 parts of modal fiber as described in any one of claims 1-9.

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