Modified polyester fiber, preparation method thereof and functional modifier

Abstract

The invention discloses a modified polyester fiber, a preparation method thereof and a functional modifier, the functional modifier is innovatively based on a metal organic framework material, the structural design of the functional modifier is optimized, specifically, antibacterial metal ions (such as titanium ions, copper ions, zinc ions and the like) are adopted as a core structure, and the antibacterial polyester fiber is prepared by compounding the metal organic framework material and the functional modifier. Harmful ions such as heavy metal with radiation are prevented from being used; meanwhile, a reactive organic chain is used as a chain extender, so that the compatibility of the metal organic framework material and a PET matrix is improved; the method specifically comprises the following steps: firstly, carrying out solvothermal reaction on metal ions and ligands; then diamine and an imidazole ligand on the surface layer of the metal organic framework material are subjected to a replacement reaction; and finally, carrying out ring-opening reaction with an epoxy compound to obtain a target material, and carrying out functional modification on the polyester fiber by using the target material through a melt spinning technology, so that the obtained modified polyester fiber at least has the functions of mechanical property, durability, antibacterial function, anti-ultraviolet function, formaldehyde removal and the like.

Description

Technical Field

[0001] This invention relates to the field of polyester fiber modification technology, specifically to a modified polyester fiber, its preparation method, and a functional modifier. Background Technology

[0002] Polyethylene terephthalate (PET) is a polymer material with excellent comprehensive properties, widely used in electronic devices, synthetic fibers, and engineering plastics. Particularly in the synthetic fiber sector, its most widespread use is in clothing, one of the essential elements of daily life. As a fiber, it is also known as polyester. Polyester fiber possesses excellent physical and mechanical properties, abrasion resistance, and is easy to wash and quick-drying, making it widely used in textile products. Since its introduction, polyester fiber has been popular and enjoys high recognition. However, polyester is easily stained by fatty oils and can breed bacteria. Furthermore, polyester textiles need to provide UV protection for the human body outdoors. Therefore, antibacterial and UV-resistant functions are currently important directions for the development of outdoor fabric products. There are two main solutions to the above problems. The first method addresses the issue at its source: adding UV-resistant additives such as nano-zinc oxide, titanium dioxide, or rare earth elements to PET polyester chips via melt spinning to obtain UV-resistant polyester fibers. However, the rare earth powders used in this method have biotoxicity and radiation risks, posing safety concerns. Only with high concentrations of nano-zinc oxide or nano-titanium dioxide can ideal UV-resistant and antibacterial effects be achieved, but this significantly reduces the mechanical properties of the polyester fibers. The second method involves applying UV-resistant and antibacterial auxiliaries to the surface of the polyester fibers using a wet finishing process. However, the polyester fibers obtained using this method have poor wash resistance and generate a large amount of wastewater during the process. Furthermore, commercially available polyester fibers also suffer from problems such as inability to remove formaldehyde and a tendency to generate static electricity, leading to insufficient wearing comfort.

[0003] It should be noted that the information disclosed in the background section above is only for understanding the background of this application. Therefore, the background section of this invention may include background information about the problems or environment of this invention, and is not necessarily a description of the prior art. Thus, the content included in the background section does not constitute an admission of the prior art by the applicant. Summary of the Invention

[0004] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide a new modified polyester fiber that can at least take into account the functions of durability, antibacterial function, anti-ultraviolet function and formaldehyde removal.

[0005] In addition, the modified polyester fiber of this invention also possesses superior mechanical properties and good antistatic effects.

[0006] The present invention also provides a functional modifier that can be used to prepare the above-mentioned modified polyester fibers and a method for preparing the above-mentioned modified polyester fibers.

[0007] To achieve the above objectives, the present invention employs the following technical solution: A modified polyester fiber, wherein the raw material of the modified polyester fiber comprises polyethylene terephthalate and a functional modifier; The functional modifier is prepared by the following method: water-soluble metal salts, carboxyl compounds, and alkyl imidazoles are dissolved in water to form a metal-organic framework material via a solvothermal method; A diamine is subjected to a substitution reaction with the imidazole structure in the metal-organic framework material to generate an amino-modified metal-organic framework material. The amino-modified metal-organic framework material is reacted with an epoxy compound to undergo an epoxy ring-opening reaction, thereby generating the functional modifier. Wherein, the water-soluble metal salt is selected from one or more combinations of titanium salt, copper salt and zinc salt, the diamine is an aliphatic diamine, and the functionality of the carboxyl compound and the functionality of the epoxy compound are both greater than or equal to 2.

[0008] Another technical solution provided by the present invention: a modified polyester fiber, wherein the raw material of the modified polyester fiber comprises polyethylene terephthalate and a functional modifier; The functional modifier is prepared by heating a water-soluble metal salt, a carboxyl compound, and an alkyl imidazole in water to produce a metal-organic framework material. The diamine is reacted with the metal-organic framework material to generate an amino-modified metal-organic framework material. The amino-modified metal-organic framework material is reacted with an epoxy compound to generate the functional modifier; The water-soluble metal salt is selected from one or more combinations of titanium salts, copper salts and zinc salts, and the functionality of the carboxyl compound and the functionality of the epoxy compound are both greater than or equal to 2.

[0009] In some embodiments of the present invention, during the preparation of the metal-organic framework material, the molar ratio of the water-soluble metal salt, the carboxyl compound, and the alkyl imidazole is 2-4:1:0.5-0.75.

[0010] In some embodiments of the present invention, the water-soluble metal salt is a metal nitrate, a metal sulfate, or a metal halide.

[0011] In some embodiments of the present invention, the carboxyl compound is selected from one or more combinations of terephthalic acid, pyromellitic acid, pyromellitic tetracarboxylic acid, 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, 4-oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid, pyridine-2,6-dicarboxylic acid, oxalic acid, succinic acid, citric acid, and aspartic acid.

[0012] In some embodiments of the present invention, the alkylimidazole is 2-C. 1-6 Alkyl imidazole. Further, the alkyl imidazole is 2-methylimidazolium and / or 2-ethylimidazolium.

[0013] In some embodiments of the present invention, the diamine is an aliphatic diamine, and further, the aliphatic diamine comprises one or more combinations of ethylenediamine, 1,3-propanediamine, tetramethylenediamine or 1,6-hexanediamine.

[0014] In some embodiments of the present invention, the molar ratio of the diamine to the alkylimidazole is 1:10-15.

[0015] In some embodiments of the present invention, the epoxy compound comprises one or more combinations of diglycidyl ether, neopentyl glycol diglycidyl ether, 2,2'-hexane-1,6-dimethyldiglycidyl ether, 1,2,5,6-diglycidyl ether, 1,2,7,8-diglycidyl ether, glycerol propoxy triglycidyl ether, and pentaerythritol glycidyl ether.

[0016] In some embodiments of the present invention, the molar ratio of the epoxy compound to the diamine is 0.8-1.2:1.

[0017] In some embodiments of the present invention, the reaction temperature of the heating reaction is controlled to be 100-140°C. Further, the reaction time of the heating reaction is controlled to be 4-12 hours.

[0018] In some embodiments of the present invention, the diamine is reacted with the metal-organic framework material under reflux conditions.

[0019] In some embodiments of the present invention, the amino-modified metal-organic framework material is reacted with the epoxy compound at 25-40°C.

[0020] In some embodiments of the present invention, the polyethylene terephthalate is added as a raw material in the form of PET chips and / or recycled PET chips.

[0021] According to the present invention, the use of recycled PET chips as raw materials can realize the resource reuse of waste.

[0022] According to some specific aspects of the present invention, polyethylene terephthalate has an intrinsic viscosity range of 0.65-0.90 dL / g and a melting point of 235-270°C.

[0023] In some embodiments of the present invention, the amount of the functional modifier added, by weight percentage, is 0.1%-5% of the amount of polyethylene terephthalate added, and more specifically 1%-3%.

[0024] In some embodiments of the present invention, the raw material of the modified polyester fiber further includes a fiber treatment agent, an antioxidant, and a lubricant; wherein, by weight, the raw material of the modified polyester fiber contains 100 parts of polyethylene terephthalate, 1-3 parts of functional modifier, 0.5-1.5 parts of fiber treatment agent, 0.2-0.8 parts of antioxidant, and 0.1-0.3 parts of lubricant.

[0025] In some embodiments of the present invention, the fiber treatment agent is a sodium phosphate salt, which comprises one or more combinations of sodium pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, sodium pentapolyphosphate, and sodium hexametaphosphate. Further, according to some specific aspects of the present invention, the fiber treatment agent is composed of sodium pyrophosphate and sodium tripolyphosphate, and even further, the mass ratio of sodium pyrophosphate to sodium tripolyphosphate is 2-4:1.

[0026] In some embodiments of the present invention, the antioxidant comprises hindered phenolic antioxidants and / or phosphite antioxidants. Further, the antioxidant is composed of hindered phenolic antioxidants and phosphite antioxidants in a mass ratio of 1:1-3. According to some specific aspects of the present invention, the hindered phenolic antioxidant may be antioxidant 1010, antioxidant 1076, antioxidant 264, antioxidant 2246, etc.; the phosphite antioxidant may be antioxidant 168, antioxidant 242, antioxidant TPP, etc.

[0027] According to one specific aspect of the present invention, the antioxidant is composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1-3.

[0028] In some embodiments of the present invention, the lubricant comprises one or more combinations of erucamide, oleamide, ethylene bis-stearamide, and oxidized polyethylene wax. Further, the lubricant is composed of oleamide and ethylene bis-stearamide, and even further, the mass ratio of oleamide to ethylene bis-stearamide is 1.5-2.5:1.

[0029] In some embodiments of the present invention, modified polyester fibers are prepared by adding functional modifiers to PET polyester chips using melt spinning technology.

[0030] Another technical solution provided by the present invention: a method for preparing the above-mentioned modified polyester fiber, the preparation method comprising: A portion of polyethylene terephthalate, a functional modifier, and a selective antioxidant are mixed together as the first component, and the remaining raw materials are used as the second component. The first component is added from the main feed port of the extruder, and the second component is added from the side feed port of the extruder. The components are melt-blended, then spun, and post-treated to obtain modified polyester fibers.

[0031] Furthermore, the temperatures of each zone of the extruder are: Zone 1 250-260℃, Zone 2 260-270℃, Zone 3 270-275℃, Zone 4 270-275℃, Zone 5 270-275℃, Zone 6 275-280℃, Zone 7 280-285℃, and Zone 8 280-285℃. The side feed port is located on the outer wall above Zone 3 or Zone 4 of the extruder temperature zone.

[0032] In some implementations, the side feed port and the main feed port are fed simultaneously.

[0033] Another technical solution provided by the present invention: a functional modifier, wherein the functional modifier is prepared by the following method: Metal-organic framework materials are prepared by heating water-soluble metal salts, carboxyl compounds, and alkyl imidazoles in water. The diamine is reacted with the metal-organic framework material to generate an amino-modified metal-organic framework material. The amino-modified metal-organic framework material is reacted with an epoxy compound to generate the functional modifier; Wherein, the water-soluble metal salt is selected from one or more combinations of titanium salts, copper salts and zinc salts, the carboxyl compound is a compound having two, three or more carboxyl groups, and the epoxy compound is a compound having two, three or more epoxy groups.

[0034] In some embodiments of the present invention, during the preparation of metal-organic framework materials, water is used as the reaction medium in a closed reaction vessel, and water-soluble metal salts, carboxyl compounds and alkyl imidazoles are used as reaction raw materials to synthesize metal-organic framework materials by a solvothermal method.

[0035] Another technical solution provided by the present invention: a functional modifier, wherein the functional modifier is prepared by the following method: Metal-organic framework materials are prepared by solvothermal reaction of water-soluble metal salts, carboxyl compounds, and alkyl imidazoles in water. A diamine is subjected to a substitution reaction with the imidazole structure in the metal-organic framework material to generate an amino-modified metal-organic framework material. The amino-modified metal-organic framework material is reacted with an epoxy compound to undergo an epoxy ring-opening reaction, thereby generating the functional modifier. Wherein, the water-soluble metal salt is one or more of titanium salts, copper salts and zinc salts, the diamine is an aliphatic diamine, the carboxyl compound is a compound having two, three or more carboxyl groups, and the epoxy compound is a compound having two, three or more epoxy groups.

[0036] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: This invention addresses the shortcomings of commercially available polyester fibers in terms of washability, mechanical properties, UV resistance, and antibacterial properties. It innovatively provides a modified polyester fiber by using a multi-modified metal-organic framework material as a functional modifier during melt extrusion, endowing the resulting modified polyester fiber with excellent antibacterial, UV-resistant, formaldehyde-removing, and antistatic properties. Furthermore, the addition of this functional modifier significantly improves the mechanical properties of the obtained modified polyester fiber. The functional modifier possesses a "quasi-hyperbranched structure" with polyepoxy groups. Although the addition of the functional modifier reduces the crystallinity of PET to some extent, thus lowering its mechanical strength, the chain extension reaction between the epoxy groups of the functional modifier and the carboxyl and hydroxyl groups generated during PET pyrolysis increases the crosslinking degree between fiber filaments. This, to some extent, compensates for the loss of mechanical strength due to the reduced crystallinity of PET, and may even improve it. Detailed Implementation

[0037] The purpose of this invention is to develop a modified polyester fiber to address the shortcomings of polyester fibers in terms of antibacterial and UV resistance. The main concept is to innovatively optimize the structure of a metal-organic framework (MOF) based on this material. Specifically, it employs antibacterial metal ions (such as titanium, copper, and zinc ions) as the core structure, avoiding the use of harmful ions such as radioactive heavy metals. Simultaneously, it uses reactive organic chains as chain extenders to improve the compatibility between the MOF and the PET matrix. The reaction mechanism is as follows: first, a solvothermal reaction occurs between metal ions and ligands; then, a diamine undergoes a substitution reaction (nucleophilic substitution) with the imidazole ligands on the surface of the MOF; finally, a ring-opening reaction occurs with an epoxy compound to obtain the target material. This target material is then used to functionally modify polyester fibers using melt spinning technology, overcoming some of the problems existing in current polyester fibers.

[0038] Furthermore, the principle of the functional modifier of the present invention for modifying polyester fiber mainly includes: (1) The present invention uses melt spinning technology to functionally modify polyester fiber, which overcomes the problem of poor wash fastness of modified polyester fiber obtained by wet impregnation of polyester fiber. The functional modifier used in the melt spinning process is an epoxy-modified metal-organic framework material, which contains epoxy groups in its molecular structure. The melt spinning process can carry out chain extension reaction with the hydroxyl and carboxyl groups of PET after melt shear decomposition, which inhibits the pyrolysis of PET to a certain extent and is very beneficial to improving the mechanical properties of the obtained modified polyester fiber. (2) The metal-organic framework material in the modified polyester fiber has a porous structure. The metal cations in the metal-organic framework material can adsorb various bacteria as active sites. The various active metal cations work together to give the obtained modified polyester fiber more excellent broad-spectrum antibacterial properties. The porous structure of the metal-organic framework material and the unsaturated bonds in the ligands can absorb or scatter ultraviolet light, so that the obtained modified polyester fiber has good anti-ultraviolet properties. (3) The modified polyester fiber obtained by the present invention also has a good formaldehyde removal effect. The formaldehyde removal effect is achieved by a variety of active sites such as the metal center, ligand, pore structure and surface defects of the metal-organic framework material in the modified polyester fiber. These active sites promote the separation and migration of photogenerated charge carriers through synergistic effect, generate active oxygen species, adsorb and activate formaldehyde molecules, thereby achieving efficient photocatalytic decomposition of formaldehyde.

[0039] Specifically, the present invention provides a modified polyester fiber comprising the following raw materials in parts by weight: 100 portions of recycled PET chips; 1-3 parts of functional modifier; 0.5-1.5 parts of fiber treatment agent; Antioxidant 0.2-0.8 parts; Lubricant 0.1-0.3 parts.

[0040] The preparation method of the above-mentioned functional modifier includes the following steps: (1) Add 4.0-8.0 mmol of metal salt (one or more of titanium salt, copper salt or zinc salt) to deionized water and dissolve it completely. Then add N,N-dimethylformamide solution containing 2.0 mmol of carboxyl compound and 1.0-1.5 mmol of alkylimidazolium. After magnetic stirring, transfer the mixed solution to a polytetrafluoroethylene reactor and react at 100-140℃ for 4-12 h. After the reaction is completed, cool to room temperature. Centrifuge the obtained reaction solution (centrifugation speed is 5000-20000 r / min, centrifugation time can be 1-20 min) and dry the obtained solid product (drying temperature can be 50-70℃, drying time can be 5-20 h) to obtain metal-organic framework material.

[0041] The carboxyl compound may be at least one of terephthalic acid, pyromellitic acid, pyromellitic tetracarboxylic acid, 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, 4-oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid, pyridine-2,6-dicarboxylic acid, oxalic acid, succinic acid, citric acid, and aspartic acid; and the carboxyl compound in the following embodiments of the present invention may be a mixture obtained by mixing terephthalic acid and aspartic acid in a molar ratio of 4:1.

[0042] Alkyl imidazoles can be 2-methylimidazolium, 2-ethylimidazolium, etc.

[0043] In this invention, both carboxyl compounds and alkyl imidazoles act as organic ligands to form the framework structure in metal-organic framework materials. Alkyl imidazoles also act as structure-directing agents, influencing the spatial structure of the metal-organic framework materials.

[0044] In this invention, the size of the metal-organic framework material is generally between tens of nanometers and tens of micrometers.

[0045] (2) 1g of metal-organic framework material was added to anhydrous ethanol, ultrasonically dispersed, and then diamine was added. The mixture was stirred and refluxed. During the reaction, the reaction was monitored using FTIR. The reaction was stopped when the concentration of the metal-organic framework material reached 1504 cm⁻¹. -1 When the absorption peak of the -C=N- coordination bond no longer weakens in the infrared spectrum, the reaction is complete. After cooling to room temperature, the reaction solution is filtered and the insoluble matter is collected. The obtained insoluble matter is washed with anhydrous ethanol and then dried (drying temperature can be 50-70℃, drying time can be 5-20h) to obtain amino-modified metal-organic framework material. The above-mentioned diamine is added according to the molar ratio of alkylimidazolium to diamine of (10.0-15.0):1.0; The aforementioned diamine is an aliphatic diamine. In its molecular structure, one amino group serves as the site for substituting alkyl imidazoles, while the other amino group forms an amino pendant structure. This pendant amino group serves as the basis for the next reaction. If the amino chain in the aliphatic diamine structure is too long, it is difficult to form an amino pendant structure; if the chain length is too short, the reaction efficiency is low, affecting the efficiency of the next modification reaction. Furthermore, the aliphatic structure is beneficial for improving the flexibility and reactivity of the functional modifier. Therefore, the aliphatic diamine can be ethylenediamine, 1,3-propanediamine, tetramethylenediamine, or 1,6-hexanediamine, etc.; and tetramethylenediamine is preferred.

[0046] In this invention, the reaction between the diamine and the metal-organic framework material is actually a substitution reaction between the diamine and the imidazole structure in the metal-organic framework material, and further, a ligand exchange reaction in which the diamine replaces the alkyl imidazole. Because alkyl imidazoles have greater steric hindrance, their coordination ability is slightly weaker than that of aliphatic diamines. Under the condition of their co-existence, the primary amine of the diamine can replace the dimethyl imidazole. Furthermore, the reaction between the diamine and alkyl imidazole is not direct; rather, the primary amine of the diamine replaces the imidazole group coordinated with the metal. Since the alkyl imidazole is added as a structure-directing agent as one of the raw materials in the early stage of the reaction, it is distributed inside and on the surface of the metal-organic framework material. The alkyl imidazole on the surface can be replaced by the diamine, while the alkyl imidazole inside is difficult to replace due to the cage effect affecting diffusion. When one end of the diamine coordinates with the metal-organic framework material, it affects the diffusion efficiency and reactivity of the diamine. With sufficient free diamine, a reaction preferentially forms with one end coordinated and the other end retained.

[0047] (3) Add 1g of amino-modified metal-organic framework material to N,N-dimethylformamide, stir and mix evenly, and then add it dropwise to N,N-dimethylformamide containing epoxy compound by stirring with a peristaltic pump. After the addition is completed, stir the reaction at a constant temperature of 25-40℃ and monitor the reaction progress with FTIR. When the absorption peak of epoxy group in the reaction system no longer weakens in the infrared spectrum, the reaction is over. Cool naturally to room temperature, filter the reaction solution and take the insoluble matter. Wash the obtained insoluble matter with anhydrous ethanol several times, and dry the obtained solid product (drying temperature can be 30-50℃, drying time can be 5-24h) to obtain epoxy-modified metal-organic framework material, i.e. functional modifier.

[0048] The amount of epoxy compound in N,N-dimethylformamide is added according to a molar ratio of 1:1 between the epoxy compound and the diamine.

[0049] The above-mentioned epoxy compounds have an average functionality ≥ 2; they can be difunctional, trifunctional, or tetrafunctional epoxy compounds or mixtures thereof; the difunctional epoxy compounds can be diepoxide ethers, neopentyl glycol diepoxide ethers, 2,2'-hexane-1,6-dimethyldiepoxide, 1,2,5,6-diepoxide hexane, 1,2,7,8-diepoxide octane, etc.; and neopentyl glycol diepoxide ethers are preferred; the trifunctional epoxy compounds can be glycerol propoxy triglycidyl ethers, etc.; the tetrafunctional epoxy compounds can be pentaerythritol glycidyl ethers.

[0050] The ring-opening reaction between an amino group (primary amine) and an epoxy group can be carried out at room temperature with some stirring. Adding a catalyst (a basic catalyst, such as triethylamine) can greatly accelerate the ring-opening reaction. In this invention, N,N-dimethylformamide solvent is used, which promotes the ring-opening reaction.

[0051] The intrinsic viscosity of the above-mentioned recycled PET chips ranges from 0.65 to 0.90 dL / g, and the melting point is 235-270℃.

[0052] The aforementioned antioxidants are hindered phenolic antioxidants and phosphite antioxidants added at a mass ratio of 1:(1-3). The hindered phenolic antioxidants may be antioxidants 1010, 1076, 264, 2246, etc.; and antioxidant 1010 is preferred. The phosphite antioxidants may be antioxidants 168, 242, TPP, etc.; and antioxidant 168 is preferred.

[0053] The aforementioned lubricants can be erucamide, oleamide, ethylene bis-stearamide, oxidized polyethylene wax, etc.

[0054] The fiber treatment agent mentioned above is a sodium phosphate salt; it can be sodium pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, sodium pentapolyphosphate, sodium hexametaphosphate, or a mixture thereof.

[0055] The functional modifiers obtained in this invention have the following types and antibacterial mechanisms: The antibacterial mechanism of Ti@metal-organic framework materials (metal-organic framework materials with titanium salts modified with epoxy groups) includes photocatalysis: under light irradiation, it can generate reactive oxygen species (such as hydroxyl radicals and singlet oxygen), which can destroy the cell membrane and cell wall of bacteria, thus achieving broad-spectrum antibacterial activity; physical adsorption: its porous structure and high specific surface area can physically adsorb bacteria, thereby achieving antibacterial effect.

[0056] Cu@metal-organic framework materials (metal-organic framework materials with epoxy groups modified by copper salts) possess intrinsic antibacterial properties and exhibit multiple antibacterial mechanisms, such as chemokinetic sterilization: copper ions generate reactive oxygen species through a catalytic Fenton reaction, which can effectively kill microorganisms; mechanical sterilization: the micro-nano structure of Cu@MOF can physically disrupt the cell walls and cell membranes of microorganisms, thereby achieving a mechanical sterilization effect; pH-responsive release of copper ions: Cu@metal-organic framework materials can rapidly dissolve in local acidic microenvironments, achieving stable, controllable, and efficient release of copper ions, thus achieving active antibacterial defense in local acidic microenvironments.

[0057] The antibacterial mechanism of Zn@metal-organic framework materials (metal-organic framework materials with zinc salts and epoxy groups) includes photocatalysis: under light irradiation, reactive oxygen species (such as hydroxyl radicals and singlet oxygen) can be generated, which can disrupt the bacterial cell membrane and cell wall, thus exhibiting broad-spectrum antibacterial activity. Metal ion release: Zn in Zn@metal-organic framework materials... 2+ It can be released into the environment, interacting with proteins and DNA on bacterial cell membranes, disrupting bacterial structure and function, thereby inhibiting bacterial growth and reproduction. Physical adsorption: Its porous structure and high specific surface area allow for the physical adsorption of bacteria, achieving an antibacterial effect. Metal-organic framework materials prepared by doping with various metal ions can achieve simultaneous antibacterial action through multiple mechanisms, exhibiting synergistic effects and enhancing the antibacterial efficacy.

[0058] The functional modifier obtained in this invention has the following UV-resistant mechanism: For example, the central metal ions of the three metal-organic framework materials (Ti@MOF, Cu@MOF, and Zn@MOF) can absorb ultraviolet light and generate photogenerated carriers under illumination. The unsaturated double bonds in the ligands of the metal-organic framework materials also have excellent absorption capacity for ultraviolet light, and their porous structure can scatter ultraviolet light, resulting in a highly efficient UV-resistant effect. Through multiple synergistic effects, the UV-resistant effect of the obtained polyester fibers is enhanced.

[0059] Furthermore, the functional modifier obtained by this invention also exhibits good formaldehyde purification and antistatic effects. As a metal-organic framework material, its porous structure can effectively adsorb small molecules such as formaldehyde (i.e., physical adsorption), while the unsaturated metal sites in the metal-organic framework material structure have highly efficient catalytic activity, resulting in a highly efficient formaldehyde purification effect (i.e., chemical reaction adsorption). Furthermore, when a metal-organic framework (MOF) absorbs photon energy, its internal electrons transition from the valence band to the conduction band, forming photogenerated electron-hole pairs. These photogenerated electrons and holes possess strong reducing and oxidizing capabilities. Electrons in the conduction band can react with oxygen molecules adsorbed on the surface of the MOF to generate superoxide anion radicals, while holes in the valence band can react with water molecules or hydroxide ions to generate hydroxyl radicals. These reactive oxygen species have strong oxidizing properties and can react with formaldehyde molecules adsorbed on the surface of the MOF, oxidizing and decomposing them into carbon dioxide and water.

[0060] In particular, the metal ions in metal-organic framework materials can react chemically with formaldehyde molecules to form coordination bonds or other chemical bonds. For example, the metal center in a metal-organic framework material can coordinate with the oxygen atom in a formaldehyde molecule, causing the formaldehyde molecule to adsorb around the metal center, thereby activating the formaldehyde molecule, reducing the activation energy of the formaldehyde oxidation reaction, and thus catalyzing its decomposition.

[0061] The functional modifier is a polyepoxy group modified structure. During the preparation process, the organic ligands all contain heteroatoms with lone pairs of electrons, which makes the obtained modified polyester fiber have good hygroscopicity. At the same time, the epoxy ring-opening reaction between amino and epoxy groups during the preparation of modified polyester fiber generates a large number of hydroxyl structures, which further enhances the hygroscopic effect of the obtained modified polyester fiber. In the chain extension reaction between polyepoxy modified polyester fiber and PET, a large number of hydroxyl structures are also generated. The abundant polyhydroxyl structures are linked together with metal ions in the metal-organic framework material structure to form a three-dimensional conductive pathway, giving the modified polyester fiber excellent antistatic effect.

[0062] The functional modifier obtained by this invention has better dispersibility in the PET substrate due to the inclusion of aliphatic organic chains (which belong to the same organic structure as PET and both contain heteroatoms O). The compatibility between the functional modifier and PET can be improved through chain extension reaction, which is conducive to the functional modifier better exerting its antibacterial, anti-ultraviolet and formaldehyde removal effects.

[0063] Meanwhile, through formulation design and combined with side-feed extrusion process, the dispersibility and compatibility of functional modifiers in PET are further improved, which can maximize the comprehensive performance of polyester fibers, such as mechanical properties, antibacterial properties, and UV resistance.

[0064] The modified polyester fiber of the present invention is prepared according to the following method: S1: Mixing; After drying each raw material, take the dry amount of the formulated functional modifier, the formulated amount of the formulated antioxidant, and 30%-50% of the formulated amount of recycled PET chips and mix them evenly to obtain component I; mix the remaining raw materials evenly to obtain component II.

[0065] S2: Melt extrusion; Component I is added from the main feed port of the extruder, while component II is added from the side feed port, and the mixture is melt-blended and extruded to obtain a melt.

[0066] In the above melt extrusion process, the screw length-to-diameter ratio of the twin-screw extruder is 40-50:1, and the rotation speed is 300-400 rpm; the temperatures of each zone are: Zone 1 250-260℃, Zone 2 260-270℃, Zone 3 270-275℃, Zone 4 270-275℃, Zone 5 270-275℃, Zone 6 275-280℃, Zone 7 280-285℃, Zone 8 280-285℃; the above side feed port is opened above the extruder corresponding to the temperature zone of Zone 3 or Zone 4 of the extruder.

[0067] S3: Spinning, post-processing, and packaging yield modified polyester fibers; The obtained melt is pumped to a secondary filter, and the filtered melt is mixed by a static mixer installed in the pipeline before entering the spinning box. The obtained nascent fibers are sequentially drawn, tensioned and heat-set, crimped and relaxed to obtain modified polyester fibers with a fiber diameter of about 10-30μm.

[0068] The primary oil bath stretching temperature is 60-70℃, the secondary steam stretching temperature is 105-115℃, and the traction-to-stretch ratio is 3.5-4.5; the tension heat setting temperature is 195-205℃; the coiling temperature is 95-105℃, the main pressure is 165-175kPa, the back pressure is 195-205kPa; the relaxation heat setting temperature is 115-125℃, and the setting time is 0.4-0.6h.

[0069] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0070] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0071] The recycled PET chips used in the following examples are recycled (semi-dull) PET chips produced by Jiangsu Ruibang Technology Co., Ltd., batch number SAO1 / 5211. The fiber treatment agent—sodium phosphate—in the following examples is composed of sodium pyrophosphate and sodium tripolyphosphate added at a mass ratio of 3:1; the antioxidants in the following examples are antioxidant 1010 and antioxidant 168 added at a mass ratio of 1:2; the lubricant in the following examples is oleamide and ethylene bis-stearamide added at a mass ratio of 2:1.

[0072] Example 1: This example provides a modified polyester fiber and its preparation method. The raw material composition, by weight, is as follows: 100 portions of recycled PET chips; 2.0 parts of functional modifier; Antioxidant 0.6 parts; 0.2 parts lubricant; 1.1 parts fiber treatment agent.

[0073] The functional modifier is prepared by the following method: 6 mmol of a metal salt (the metal salt was prepared by mixing titanium chloride and copper nitrate in a molar ratio of 1:2) was added to 50 mL of deionized water and dissolved completely. Then, 20 mL of an N,N-dimethylformamide solution containing 2.0 mmol of a carboxyl compound (the carboxyl compound was prepared by mixing terephthalic acid and aspartic acid in a molar ratio of 4:1) and 1.2 mmol of 2-methylimidazole was added. The mixture was magnetically stirred for 0.5 h, and then transferred to a polytetrafluoroethylene reactor. The mixture was reacted at 120 °C for 10 h. After the reaction was completed, the temperature was lowered to room temperature. The resulting reaction solution was centrifuged at 10000 r / min for 5 min, and the resulting solid product was dried at 60 °C for 8 h to obtain the metal-organic framework material.

[0074] (2) 1 g of metal-organic framework material was added to 150 mL of anhydrous ethanol and ultrasonically dispersed for 2 h. Then, diamine was added, and the mixture was stirred and refluxed. During the reaction, the reaction was monitored using FTIR. The reaction was stopped when the concentration of the metal-organic framework material in the reaction system reached 150 mL / cm³. -1 The absorption peak of the -C=N- coordination bond no longer weakens in the infrared spectrum, the reaction is over, the reaction is cooled to room temperature, the reaction solution is filtered and the insoluble matter is taken, the obtained insoluble matter is washed with anhydrous ethanol and dried at 60℃ for 12h to obtain amino-modified metal-organic framework material. The above-mentioned diamine was added according to a molar ratio of 2-methylimidazole to diamine of 12:1.0; The aforementioned diamine is tetramethylenediamine.

[0075] (3) Add 1g of amino-modified metal-organic framework material to 100mL of N,N-dimethylformamide, stir and mix evenly, and then add it dropwise to 50mL of N,N-dimethylformamide containing neopentyl glycol diglycidyl ether by a peristaltic pump while stirring. After the addition is completed, stir the reaction at 25℃ and monitor the reaction progress by FTIR. When the absorption peak of the epoxy group in the reaction system no longer weakens in the infrared spectrum, the reaction is over. Cool naturally to room temperature, filter the reaction solution and take the insoluble matter. Wash the obtained insoluble matter three times with 100mL of anhydrous ethanol. Dry the obtained solid product at 40℃ for 12h to obtain the epoxy-modified metal-organic framework material, i.e., the functional modifier. The molar ratio of neopentyl glycol diepoxyglycerol ether to diamine is 1:1.

[0076] The modified polyester fiber is prepared according to the following method: S1: Mixing; After drying each raw material at 80℃ for 24 hours, the following components were mixed evenly: the dry amount of functional modifier, the amount of antioxidant, and 40% of the amount of recycled PET chips to obtain component I; the remaining raw materials were mixed evenly to obtain component II.

[0077] S2: Melt extrusion; Component I is added from the main feed port of the extruder, while component II is added from the side feed port, and the mixture is melt-blended and extruded to obtain a melt.

[0078] In the above melt extrusion process, the screw length-to-diameter ratio of the twin-screw extruder is 44:1, and the rotation speed is 340 rpm; the temperatures of each zone are: Zone 1 255℃, Zone 2 265℃, Zone 3 270℃, Zone 4 272℃, Zone 5 275℃, Zone 6 278℃, Zone 7 282℃, and Zone 8 282℃; the above side feed ports are opened on the upper outer wall of the extruder corresponding to the three zones of the extruder.

[0079] S3: Spinning, post-processing, and packaging yield modified polyester fibers; The obtained melt is pumped to a secondary filter, and the filtered melt is mixed by a static mixer installed in the pipeline before entering the spinning box. The obtained nascent fibers are sequentially drawn, tensioned and heat-set, crimped and relaxed to obtain modified polyester fibers with a fiber diameter of about 30μm.

[0080] The primary oil bath stretching temperature is 65℃, the secondary steam stretching temperature is 110℃, and the traction stretching ratio is 4.0; the tension heat setting temperature is 200℃; the coiling temperature is 100℃, the main pressure is 170kPa, the back pressure is 200kPa; the relaxation heat setting temperature is 120℃, and the setting time is 0.5h.

[0081] Example 2: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1, except that in Example 2, the amount of functional modifier added is 1 part by weight, the amount of antioxidant added is 0.2 parts by weight, the amount of lubricant added is 0.3 parts by weight, and the amount of fiber treatment agent added is 1.5 parts by weight. During melt extrusion, the twin-screw extruder has a screw length-to-diameter ratio of 50:1 and a rotation speed of 400 rpm; the temperatures of each zone are: Zone 1 250℃, Zone 2 260℃, Zone 3 270℃, Zone 4 270℃, Zone 5 270℃, Zone 6 275℃; Zone 7 280℃; Zone 8 280℃; the side feed port is located on the outer wall above the extruder corresponding to Zone 4.

[0082] Example 3: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1, except that in Example 3, the amount of functional modifier added is 3 parts by weight, the amount of antioxidant added is 0.8 parts by weight, the amount of lubricant added is 0.1 parts by weight, and the amount of fiber treatment agent added is 0.5 parts by weight. During melt extrusion, the twin-screw extruder has a screw length-to-diameter ratio of 40:1 and a rotation speed of 300 rpm; the temperatures of each zone are: Zone 1 260℃, Zone 2 270℃, Zone 3 273℃, Zone 4 275℃, Zone 5 275℃, Zone 6 270℃; Zone 7 285℃; Zone 8 285℃; the side feed port is located on the outer wall above the extruder corresponding to Zone 3.

[0083] Example 4: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1, except that the amount of functional modifier added in Example 4 is 1.5 parts by weight, the amount of antioxidant added is 0.6 parts by weight, the amount of lubricant added is 0.2 parts by weight, and the amount of fiber treatment agent added is 1.1 parts by weight.

[0084] Example 5: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1, except that the amount of functional modifier added in Example 5 is 2.5 parts by weight, the amount of antioxidant added is 0.6 parts by weight, the amount of lubricant added is 0.2 parts by weight, and the amount of fiber treatment agent added is 1.1 parts by weight.

[0085] Example 6: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1. The difference is that in the preparation process of the functional modifier in Example 6, the amount of metal salt added is 4 mmol and the amount of 2-methylimidazole added is 1 mmol.

[0086] Example 7: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1. The difference is that in the preparation process of the functional modifier in Example 7, the amount of metal salt added is 8 mmol and the amount of 2-methylimidazole added is 1.5 mmol.

[0087] Example 8: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1, except that the metal salt in Example 8 is a mixture of titanium chloride and zinc nitrate in a molar ratio of 1:2.

[0088] Example 9: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1, except that the metal salt in Example 9 is titanium chloride.

[0089] Example 10: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1, except that the metal salt in Example 10 is copper nitrate.

[0090] Example 11: This example provides a modified polyester fiber and its preparation method, which is basically the same as Example 1, except that in Example 11, an equal molar amount of glycerol propoxy triglycidyl ether is used to replace neopentyl glycol diglycidyl ether in Example 1.

[0091] Example 12: This example provides a modified polyester fiber and its preparation method, which is basically the same as in Example 1, except that in Example 12, the same molar amount of pentaerythritol glycidyl ether is used to replace neopentyl glycol diglycidyl ether in Example 1.

[0092] Comparative Example 1: The results are basically the same as in Example 1, except that no functional modifier was added to the raw materials of the polyester fiber in Comparative Example 1.

[0093] Comparative Example 2: The basic structure is the same as that of Example 1, except that Comparative Example 2 uses the metal-organic framework material obtained in step (1) of Example 1 with the same weight as the functional modifier in Example 1.

[0094] Comparative Example 3: The basic process is the same as in Example 1, except that the metal salt used in the preparation of the functional modifier in Comparative Example 3 is a mixture of titanium chloride and ferric chloride in a molar ratio of 1:2.

[0095] Comparative Example 4: The basic structure is the same as in Example 1, except that in Comparative Example 4, the amino-modified metal-organic framework material obtained in step (2) of Example 1 is added in the same weight proportion to replace the functional modifier in Example 1.

[0096] Comparative Example 5: The basic structure is the same as in Example 1, except that in Comparative Example 5, the functional modifier in Example 1 is replaced by a mixture of amino-modified metal-organic framework material obtained in step (2) of Example 1 and neopentyl glycol diglycidyl ether in a mass ratio of 35.3:1.

[0097] Comparative Example 6:

[0098] The basic structure is the same as in Example 1, except that the epoxy compound used in Comparative Example 6 is n-butyl glycidyl ether.

[0099] Comparative Example 7: The basic principle is the same as in Example 1, except that in Comparative Example 7, all raw materials are added simultaneously from the main feed port.

[0100] Performance testing: The modified polyester fibers obtained in Examples 1-12 and Comparative Examples 1-7 of this invention were subjected to relevant performance tests, and the specific test results are shown in Table 1. The test methods are as follows: (1) Tensile strength: The test shall be conducted in accordance with the method described in GB / T 14337 2008.

[0101] (2) Elongation at break: The test shall be conducted in accordance with the method described in GB 9997-88.

[0102] (3) Antibacterial properties: The method described in standard GB / T 20944.3 2008 "Evaluation of antibacterial properties of textiles" was used for testing.

[0103] (4) UV resistance: Tested according to the method described in GB / T 18830 2009.

[0104] (5) Formaldehyde adsorption performance: a. According to the national standard GB / T15516-1995, the concentration of formaldehyde was measured by the acetylacetone spectrophotometric method in this experiment. Formaldehyde reacts with acetylacetone in an acetate-ammonium acetate buffer solution at pH=6 to form a stable yellow compound, diacetyldihydrorutidine, under water bath conditions, which has an absorption peak at a wavelength of 413 nm.

[0105] b. Preparation of 0.25% acetylacetone solution Weigh 25g of ammonium acetate, dissolve it in a small amount of water, then transfer it to a 100mL volumetric flask, add 3mL of glacial acetic acid and 0.25mL of acetylacetone, then add distilled water to the mark and shake well.

[0106] c, the standard curve obtained from the test. 0.1 mL, 1 mL, 2 mL, 4 mL, 6 mL, 8 mL, and 10 mL of a 12.8 μg / mL formaldehyde aqueous solution were respectively added to 25 mL volumetric flasks and diluted to volume. Then, 4 mL of the diluted formaldehyde aqueous solution was transferred to each test tube, and 4 mL of 0.25% acetylacetone solution was added to each test tube. The tubes were placed in a water bath at 40 °C for 30 min for color development. After development, the tubes were removed and allowed to cool naturally at room temperature for 30 min. The absorbance of formaldehyde was then measured at a wavelength of 413 nm, and a standard curve was plotted. The fitted curve equation is Y = 0.03926X + 0.04772.

[0107] d. Determination of formaldehyde adsorption capacity A formaldehyde aqueous solution with an initial concentration of 6.4 μg / mL was prepared. The modified polyester fibers obtained in the embodiments and comparative examples of this invention were placed in conical flasks, and 50 mL of the prepared formaldehyde aqueous solution with an initial concentration of 6.4 μg / mL was poured in. The flasks were immediately sealed and placed in a constant temperature water bath (18℃) with shaking for 24 hours for adsorption. After the reaction was completed, the concentration of formaldehyde in the solution was measured, and a blank test with the corresponding concentration (without the addition of modified polyester fibers) was set up. The formula for calculating the formaldehyde adsorption capacity is as follows: Q = (((A0-As)×Bs) / m)×(V1 / V2); Where A0 is the absorbance of the blank test; AS is the absorbance of the test solution; Bs is the calibration factor, the reciprocal of the slope of the standard curve; V1 is the volume of the formaldehyde aqueous solution, mL; V2 is the volume of the sample taken for testing, mL; and m is the mass of the modified polyester fiber, g.

[0108] (6) Volume resistivity: Tested according to the method described in GB / T 14342-2015.

[0109]

[0110] First, as can be seen from Examples 1-12 in Table 1, the modified polyester fiber obtained by the present invention has excellent mechanical properties, antibacterial and UV resistance, formaldehyde removal properties, and also excellent antistatic properties.

[0111] Comparing Example 1 with Comparative Example 1, it can be seen that the functional additives in the modified polyester fibers obtained by the present invention have excellent antibacterial and UV resistance, formaldehyde adsorption, and antistatic properties. Furthermore, they can improve the mechanical properties of the modified polyester fibers. The possible reasons are: the functional modifiers adjust the regularity of the PET molecular chains, reduce the crystallinity of PET, and improve the flexibility of the modified polyester fibers; on the other hand, the chain extension reaction of the functional modifiers increases the molecular weight of PET, thereby improving the strength of the obtained modified polyester fibers.

[0112] A comparison of Example 1 with Comparative Examples 2-4 shows that the epoxy-modified metal-organic framework material of the present invention has a better promoting effect on the antibacterial, anti-ultraviolet, antistatic and mechanical properties of the obtained modified polyester fibers.

[0113] Comparing Example 1 with Comparative Example 5, it can be seen that, compared with physical blending, the functional modifier has excellent mechanical properties after chemical modification, and its anti-ultraviolet, antibacterial, and antistatic properties are better.

[0114] Comparing Example 1 with Comparative Example 6, it can be seen that the functional modifier has an epoxy-terminated structure, which has excellent chain extension effect. At the same time, the chain extension generates a large number of hydroxyl groups, which is reflected in the excellent mechanical properties, better anti-ultraviolet and antistatic effects.

[0115] Comparing Example 1 with Comparative Example 7, it can be seen that the modified polyester fiber obtained by using a combination of main feed and side feed melt extrusion has better mechanical properties and UV resistance, antibacterial properties.

[0116] In summary, this invention provides a modified polyester fiber. During the melt extrusion process, an epoxy-modified metal-organic framework material is used as a functional modifier, which endows the obtained modified polyester fiber with excellent mechanical properties, antibacterial and UV resistance, formaldehyde removal, and antistatic properties, and has good market prospects.

[0117] Furthermore, this invention relates to the field of polyester fiber modification technology, specifically to a method for functionalizing polyester fibers with UV resistance and other properties. Conventional wet impregnation finishing methods result in modified polyester fibers with poor UV resistance, antibacterial properties, and insufficient wash fastness. To address these technical problems, this invention utilizes melt spinning technology to add epoxy-modified metal-organic framework (MOF) materials as functional modifiers to recycled PET chips. The metal cations in the MOF material's structure act as active sites, adsorbing various bacteria and endowing the obtained modified polyester fibers with excellent broad-spectrum antibacterial properties. The porous structure of the MOF material and the unsaturated bonds in the ligands can absorb or scatter ultraviolet light, resulting in modified polyester fibers with good UV resistance. Simultaneously, it achieves unexpectedly excellent results in mechanical properties and antistatic properties, overcoming the problems of poor wash fastness, insufficient UV resistance, and insufficient antibacterial properties found in existing modified polyester fibers.

[0118] As used throughout the specification and claims, the term "comprising" is an open-ended term and should be interpreted as "comprising but not limited to." "Substantially" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect. It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the product or system comprising said element.

[0119] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0120] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A modified polyester fiber, characterized in that, The raw materials for the modified polyester fiber include polyethylene terephthalate and functional modifiers; The functional modifier is prepared by the following method: water-soluble metal salts, carboxyl compounds, and alkyl imidazoles are dissolved in water to form a metal-organic framework material via a solvothermal method; A diamine is subjected to a substitution reaction with the imidazole structure in the metal-organic framework material to generate an amino-modified metal-organic framework material. The amino-modified metal-organic framework material is reacted with an epoxy compound to undergo an epoxy ring-opening reaction, thereby generating the functional modifier. Wherein, the water-soluble metal salt is selected from one or more combinations of titanium salt, copper salt and zinc salt, the diamine is an aliphatic diamine, and the functionality of the carboxyl compound and the functionality of the epoxy compound are both greater than or equal to 2.

2. The modified polyester fiber according to claim 1, characterized in that, In the preparation of metal-organic framework materials, the molar ratio of the water-soluble metal salt, the carboxyl compound, and the alkyl imidazole is 2-4:1:0.5-0.75; and / or, the water-soluble metal salt is a metal nitrate, metal sulfate, or metal halide; and / or, the carboxyl compound is selected from one or more combinations of terephthalic acid, trimesic acid, pyromellitic acid, 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, 4-oxo-1,4-dihydro-2,6-pyridinedicarboxylic acid, pyridine-2,6-dicarboxylic acid, oxalic acid, succinic acid, citric acid, and aspartic acid; and / or, the alkyl imidazole is 2-C 1-6 Alkyl imidazole, further wherein the alkyl imidazole is 2-methylimidazolium and / or 2-ethylimidazolium.

3. The modified polyester fiber according to claim 1, characterized in that, The aliphatic diamine comprises one or more combinations of ethylenediamine, 1,3-propanediamine, tetramethylenediamine, or 1,6-hexanediamine; and / or, the molar ratio of the diamine to the alkylimidazole is 1:10-15.

4. The modified polyester fiber according to claim 1, characterized in that, The epoxy compound comprises one or more combinations of diepoxyglycerol ether, neopentyl glycol diepoxyglycerol ether, 2,2'-hexane-1,6-dimethyldiepoxyethylene, 1,2,5,6-diepoxyhexane, 1,2,7,8-diepoxyoctane, glycerol propoxy triglycidyl ether, and pentaerythritol glycidyl ether; and / or, the molar ratio of the epoxy compound to the diamine is 0.8-1.2:

1.

5. The modified polyester fiber according to claim 1, characterized in that, The reaction temperature of the heating reaction is controlled at 100-140°C; and / or, the diamine is reacted with the metal-organic framework material under reflux conditions; and / or, the amino-modified metal-organic framework material is reacted with the epoxy compound at 25-40°C.

6. The modified polyester fiber according to claim 1, characterized in that, The polyethylene terephthalate is added as a raw material in the form of PET chips and / or recycled PET chips; and / or, by mass percentage, the amount of the functional modifier added is 0.1%-5% of the amount of polyethylene terephthalate added, and more specifically 1%-3%.

7. The modified polyester fiber according to claim 1, characterized in that, The modified polyester fiber raw material further includes a fiber treatment agent, an antioxidant, and a lubricant; wherein, by weight, the modified polyester fiber raw material contains 100 parts polyethylene terephthalate, 1-3 parts functional modifier, 0.5-1.5 parts fiber treatment agent, 0.2-0.8 parts antioxidant, and 0.1-0.3 parts lubricant; and / or, The fiber treatment agent is a sodium phosphate salt, which comprises one or more combinations of sodium pyrophosphate, sodium tripolyphosphate, sodium tetrapolyphosphate, sodium pentapolyphosphate, and sodium hexametaphosphate; and / or, The antioxidant comprises hindered phenolic antioxidants and / or phosphite antioxidants; and / or, The lubricant comprises one or more of erucamide, oleamide, ethylene bis-stearamide, and oxidized polyethylene wax.

8. The modified polyester fiber according to claim 7, characterized in that, The antioxidant is composed of hindered phenolic antioxidants and phosphite antioxidants in a mass ratio of 1:1-3; and / or, the lubricant is composed of oleamide and ethylene bis-stearamide in a mass ratio of 1.5-2.5:1; and / or, the fiber treatment agent is composed of sodium pyrophosphate and sodium tripolyphosphate in a mass ratio of 2-4:

1.

9. A method for preparing the modified polyester fiber according to any one of claims 1-8, characterized in that, The preparation method includes: A portion of polyethylene terephthalate, a functional modifier, and a selective antioxidant are mixed together as the first component, and the remaining raw materials are used as the second component. The first component is added from the main feed port of the extruder, and the second component is added from the side feed port of the extruder. The components are melt-blended, then spun, and post-treated to obtain modified polyester fibers.

10. A functional modifier, characterized in that, The functional modifier is prepared by the following method: Metal-organic framework materials are prepared by solvothermal reaction of water-soluble metal salts, carboxyl compounds, and alkyl imidazoles in water. A diamine is subjected to a substitution reaction with the imidazole structure in the metal-organic framework material to generate an amino-modified metal-organic framework material. The amino-modified metal-organic framework material is reacted with an epoxy compound to undergo an epoxy ring-opening reaction, thereby generating the functional modifier. Wherein, the water-soluble metal salt is one or more of titanium salts, copper salts and zinc salts, the diamine is an aliphatic diamine, the carboxyl compound is a compound having two, three or more carboxyl groups, and the epoxy compound is a compound having two, three or more epoxy groups.

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