Mordant-free dyeing method

Abstract

A method of dyeing a textile, the method including depositing a metal-organic framework (MOF) on at least one surface of the textile thereby forming a MOF functionalized textile; contacting the MOF functionalized textile with a dye thereby forming a dyed textile; and optionally drying the dyed textile. Metal-organic framework functionalized textiles can be dyed with natural dyes effectively with higher dye uptake and colorfastness without the use of traditional mordants.

Description

MORDANT-FREE DYEING METHOD 無媒染劑的染色方法 TECHNICAL FIELD [1] The present disclosure generally relates to a mordant-free textile dyeing method and dyed textile products thereof. BACKGROUND [2] Synthetic dyes have been commonly used to dye textile fibers and fabrics due in part to their ease of application, low cost, and good colorfastness. However, both synthetic dye production and waste treatment processes have created severe environmental hazards. In particular, azo dye-containing effluent can lead to environmental hazards, because azo-based dyes and their breakdown products are toxic to aquatic life and mutagenic to humans. Thus, many countries have restricted the use of certain azo-based dyes. [3] Natural dyes are sustainable and biodegradable. However, their application is limited due to their poor affinity with textile fibers and fabrics, leading to low dye uptake, colorfastness, and reproducibility. Thus, natural dyes are usually used with mordants. Common mordants include ferrous sulphate, copper sulfate, chrome, alum, and stannous chloride. However, the use of harmful heavy metal mordants can lead to water pollution, which can incur additional cost for wastewater treatment. In addition, the amount of mordant needs to be carefully controlled, as using too much mordant can lead to discoloration and damage to textile fibers and fabrics. [4] Different methods have been utilized to enhance natural dye uptake of fabrics. Some involve the development of new mordant baths with the use of inorganic salts, e.g., alum, soda ash, or rare earth elements. However, the use of such mordants can also lead to water pollution. CN102199883A discloses a mordant-free dyeing method for protein fiber in which sodium alginate was used as an environmentally-friendly additive to replace conventional mordants. However, this method is limited to dyeing protein fiber with monascorubin. CN102561058B discloses a method for improving natural dyeing property of cotton fabric by using silk peptide. The cotton fiber is modified via a two-step process before dyeing: (1) oxidation; (2) coating of silk peptide on the oxidized cotton. The K / S value of the treated fabric was almost 4 times 1 HK 20106287 B higher than that of the control fabric. The resulting dyed fabric obtained 3 – 4 grades of soaping fastnesses, and 4 – 5 grades of crock fastness. However, sodium periodate was used as the oxidizing agent in the surface modification process, which is toxic. Plasma treatment has been used to induce surface charge on a fabric surface, which enhances the dyeing effect of natural dyes. Examples are WO2015088920A1, CN103485160A and CN102277754A. However, plasma treatment is a costly process. [5] Metal-organic frameworks (MOFs) are a class of compounds consisting of metal ions or clusters coordinated to organic ligands having one-, two-, or three-dimensional crystalline frameworks. With different combinations of metal ions and ligands, the pore size of the MOFs can be adjusted, fitting for various adsorption applications such as hydrogen storage, gas separation, etc. For examples, MOFs were utilized as selective adsorbents for gas separation purposes in US20150027309A1 and WO2011123795A1. Two MOFs, namely ZIF-8 and MIL- 101, were applied to non-woven bags for micro SPE applications in CN103599764A and CN103611510A respectively. DE102009042643A1 discloses MOF-functionalized fabrics for application in textile filter material. In US11092562B2 and US20210230191A1, the MOF- functionalized fabrics can be used for sensors to detect analytes such as nitric oxide (NO), dopamine (DA), hydrogen sulfide (H2S), etc. [6] In the context of the above, there remains a need in the art for an effective and general natural dyeing method for common fabrics without the use of harmful mordants. Therefore, there is a need to develop a mordant-free natural dyeing method, so that the natural dye uptake and colorfastness can be enhanced. With the improvement of dyeing performance, the use of more environmentally friendly natural dyes can be promoted in the textile industry. SUMMARY [7] The present disclosure provides a mordant-free dyeing method for fabrics, that can enhance the dyeing performance of natural dyes. With fabric surface modification by MOF prior to dyeing, the functionalized fabric can adsorb natural dyes at greater extent, leading to better dye uptake and colorfastness. Thus, the natural dyeing performance can be improved. [8] In a first aspect, provided herein is a method of dyeing a textile, the method comprising: depositing a metal-organic framework (MOF) on at least one surface of the textile thereby 2 HK 20106287 B forming a MOF functionalized textile; contacting the MOF functionalized textile with a dye thereby forming a dyed textile; and optionally drying the dyed textile. [9] In certain embodiments, the MOF comprises at least one metal ion selected from the group consisting of sodium (I), potassium (I), calcium (II), magnesium (II), aluminum (III), copper (II), zinc (II), titanium (IV), zirconium (IV), and combinations thereof.

[10] In certain embodiments, the MOF comprises at least one ligand selected from the group consisting of an aryl dicarboxylate, a heteroaryl dicarboxylate, an aryl tricarboxylate, a heteroaryl tricarboxylate, an aryl tetracarboxylate, a heteroaryl tetracarboxylate, an imidazole, a benzimidazole, and conjugate acids thereof.

[11] In certain embodiments, the MOF comprises at least one metal ion selected from the group consisting of magnesium (II), aluminum (III), copper (II), zinc (II), titanium (IV), and zirconium (IV); and at least one ligand selected from the group consisting of 2-methyl-1H- imidazole, 2-ethyl-1H-imidazole, 2-methyl-1H-benzimidazole, 2,5-furandicarboxylate, 1,4- benzenedicarboxylate, 2-aminobenzene-1,4-dicarboxylate, 2-hydroxybenzene-1,4- dicarboxylate, 1,3-benzenedicarboxylate, naphthalene-1,4-dicarboxylate, 4-(4- carboxyphenyl)benzoate, benzene-1,3,5-tricarboxylate, 4,4’,4’’-benzene-1,3,5-triyl- tribenzoate, 1,2,4,5-benzenetetracarboxylate, and conjugate acids thereof.

[12] In certain embodiments, the MOF comprises aluminum (III) benzene-1,3,5- tricarboxylate, zinc (II) 2,5-furandicarboxylate, or a conjugate acid thereof.

[13] In certain embodiments, the method does not comprise a mordant.

[14] In certain embodiments, the dye is a natural dye.

[15] In certain embodiments, the step of depositing the MOF comprises: contacting the textile with a MOF precursor solution thereby forming the MOF functionalized textile, wherein MOF precursor solution comprises: at least one metal ion selected from the group consisting of magnesium (II), aluminum (III), copper (II), zinc (II), titanium (IV), and zirconium (IV); and at least one ligand selected from the group consisting of an aryl dicarboxylate, a heteroaryl dicarboxylate, an aryl tricarboxylate, a heteroaryl tricarboxylate, an aryl tetracarboxylate, a heteroaryl tetracarboxylate, an imidazole, a benzimidazole, and 3 HK 20106287 B conjugate acids thereof; or contacting the textile with a first solution comprising at least one metal salt and a second solution comprising at least one ligand thereby forming the MOF functionalized textile, wherein the at least one metal salt comprises magnesium (II), aluminum (III), copper (II), zinc (II), titanium (IV), zirconium (IV), or a combination thereof; and the at least one ligand is selected from the group consisting of an aryl dicarboxylate, a heteroaryl dicarboxylate, an aryl tricarboxylate, a heteroaryl tricarboxylate, an aryl tetracarboxylate, a heteroaryl tetracarboxylate, an imidazole, a benzimidazole, and conjugate acids thereof, wherein the first solution and the second solution are contacted with the textile sequentially or concurrently.

[16] In certain embodiments, the MOF precursor solution comprises the at least one metal salt at a concentration between 0.1 to 0.5 M and the at least one ligand at a concentration between 0.05 to 0.5 M; or the first solution comprises the at least one metal salt at a concentration between 0.1 to 0.5 M and the second solution comprises the at least one ligand at a concentration between 0.05 to 0.5 M.

[17] In certain embodiments, the step of depositing the MOF is repeated one or more times.

[18] In certain embodiments, the step of depositing the MOF further comprises ultrasonication.

[19] In certain embodiments, the method further comprises the step of contacting the textile with citric acid prior to the step of depositing the MOF.

[20] In certain embodiments, the textile comprises cotton, wool, or polycotton.

[21] In certain embodiments, the dye is a natural dye.

[22] In certain embodiments, the MOF functionalized textile is contacted with an aqueous solution of the dye at a temperature between 40-95 °C.

[23] In certain embodiments, the dye is a natural dye; and the aqueous solution comprises the natural dye at 0.5 to 20 on-weight-fabric (owf)%.

[24] In certain embodiments, the textile comprises cotton, wool, or polycotton; the MOF comprises aluminum (III) benzene-1,3,5-tricarboxylate, zinc (II) 2,5-furandicarboxylate, or a 4 HK 20106287 B conjugate acid thereof; and the step of depositing the MOF comprises: contacting the textile with a MOF precursor solution comprising a metal salt comprising aluminum (III) or zinc (II) and a ligand selected from the group consisting of benzene-1,3,5-tricarboxylate, 2,5- furandicarboxylate, and conjugate acids thereof, wherein the metal salt and the ligand are independently present a concentration between 0.05 to 0.5 M in the MOF precursor solution; or the step of depositing the MOF comprises: contacting the textile with a first solution comprising a metal salt comprising aluminum (III) or zinc (II) and a second solution comprising a ligand selected from the group consisting of benzene-1,3,5-tricarboxylate, 2,5- furandicarboxylate, and conjugate acids thereof, wherein the metal salt is present in the first solution at a concentration of 0.1 to 0.5 M and the ligand is present in the second solution at a concentration of 0.05 to 0.5 M.

[25] In certain embodiments, the step of contacting the textile with the MOF precursor solution further comprises ultrasonication; or the step of contacting the textile with the first solution and the second solution further comprises ultrasonication.

[26] In certain embodiments, the MOF functionalized textile is contacted with an aqueous solution of the dye at a temperature between 70-90 °C, wherein the dye is a natural dye; and the aqueous solution comprises the natural dye at 0.5 to 20 on-weight-fabric (owf)%.

[27] A dyed textile prepared according to a method described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[28] Figure 1 depicts Fourier-transform infrared (FTIR) spectroscopy spectrums of cotton, ZnFDCA, and ZnFDCA@cotton.

[29] Figure 2 depicts FTIR spectrums of cotton, MIL-96, and MIL-96@cotton.

[30] Figure 3 depicts FTIR spectrums of polycotton, MIL-96, and MIL-96@polycotton.

[31] Figure 4 depicts FTIR spectrums of wool, MIL-96, and MIL-96@wool.

[32] Figure 5 depicts a scanning electron microscopy SEM image and an Energy-dispersive X-ray spectroscopy (EDX) image of MIL-96@cotton.

[33] Figure 6 depicts a SEM image and a EDX image of MIL-96@polycotton. 5 HK 20106287 B

[34] Figure 7 depicts a SEM image and a EDX image of MIL-96@wool.

[35] Figure 8 depicts exemplary ligands useful in the preparation of the MOF functionalized textiles in accordance with certain embodiments of the methods described herein. DETAILED DESCRIPTION

[36] Definition

[37] The following terms shall be used to describe the present invention. In the absence of a specific definition set forth herein, the terms used to describe the present invention shall be given their common meaning as understood by those of ordinary skill in the art.

[38] Throughout the application, where compositions are described as having, including, or comprising specific components, or where processes are described as having, including, or comprising specific process steps, it is contemplated that compositions of the present teachings can also consist essentially of, or consist of, the recited components, and that the processes of the present teachings can also consist essentially of, or consist of, the recited process steps.

[39] In the application, where an element or component is said to be included in and / or selected from a list of recited elements or components, it should be understood that the element or component can be any one of the recited elements or components, or the element or component can be selected from a group consisting of two or more of the recited elements or components. Further, it should be understood that elements and / or features of a composition or a method described herein can be combined in a variety of ways without departing from the spirit and scope of the present teachings, whether explicit or implicit herein.

[40] It should be understood that the order of steps or order for performing certain actions is immaterial so long as the present teachings remain operable. Moreover, two or more steps or actions may be conducted simultaneously.

[41] The use of the singular herein includes the plural (and vice versa) unless specifically stated otherwise. In addition, where the use of the term "about" is before a quantitative value, the present teachings also include the specific quantitative value itself, unless specifically stated otherwise. As used herein, the term "about" refers to a ±10%, ±7%, ±5%, ±3%, ±1%, or ±0% variation from the nominal value unless otherwise indicated or inferred.

[42] As used herein, "heteroatom" refers to an atom of any element other than carbon or 6 HK 20106287 B hydrogen and includes, for example, nitrogen, oxygen, silicon, sulfur, phosphorus, and selenium.

[43] As used herein, "aryl" refers to an aromatic monocyclic hydrocarbon ring system or a polycyclic ring system in which two or more aromatic hydrocarbon rings are fused (i.e., having a bond in common with) together or at least one aromatic monocyclic hydrocarbon ring is fused to one or more cycloalkyl and / or cycloheteroalkyl rings. An aryl group can have 6 to 24 carbon atoms in its ring system (e.g., C6-24 aryl group), which can include multiple fused rings. In certain embodiments, a polycyclic aryl group can have 8 to 24 carbon atoms. Any suitable ring position of the aryl group can be covalently linked to the defined chemical structure. Examples of aryl groups having only aromatic carbocyclic ring(s) include phenyl, 1-naphthyl (bicyclic), 2-naphthyl (bicyclic), anthracenyl (tricyclic), phenanthrenyl (tricyclic), pentacenyl (pentacyclic), and like groups. Examples of polycyclic ring systems in which at least one aromatic carbocyclic ring is fused to one or more cycloalkyl and / or cycloheteroalkyl rings include, among others, benzo derivatives of cyclopentane (i.e., an indanyl group, which is a 5,6-bicyclic cycloalkyl / aromatic ring system), cyclohexane (i.e., a tetrahydronaphthyl group, which is a 6,6-bicyclic cycloalkyl / aromatic ring system), imidazoline (i.e., a benzimidazolinyl group, which is a 5,6-bicyclic cycloheteroalkyl / aromatic ring system), and pyran (i.e., a chromenyl group, which is a 6,6-bicyclic cycloheteroalkyl / aromatic ring system). Other examples of aryl groups include benzodioxanyl, benzodioxolyl, chromanyl, indolinyl groups, and the like. In certain embodiments, aryl groups can be optionally substituted. In certain embodiments, an aryl group can have one or more halogen substituents, and can be referred to as a "haloaryl" group. Perhaloaryl groups, i.e., aryl groups where all of the hydrogen atoms are replaced with halogen atoms (e.g., - C6F5), are included within the definition of "haloaryl." In certain embodiments, an aryl group is substituted with another aryl group and can be referred to as a biaryl group. Each of the aryl groups in the biaryl group can be optionally substituted.

[44] As used herein, "heteroaryl" refers to an aromatic monocyclic ring system containing at least one ring heteroatom selected from oxygen (O), nitrogen (N), sulfur (S), silicon (Si), and selenium (Se) or a polycyclic ring system where at least one of the rings present in the ring system is aromatic and contains at least one ring heteroatom. Polycyclic heteroaryl groups 7 HK 20106287 B include those having two or more heteroaryl rings fused together, as well as those having at least one monocyclic heteroaryl ring fused to one or more aromatic carbocyclic rings, non- aromatic carbocyclic rings, and / or non-aromatic cycloheteroalkyl rings. A heteroaryl group, as a whole, can have, for example, 5 to 24 ring atoms and contain 1-5 ring heteroatoms (i.e., 5-20 membered heteroaryl group). The heteroaryl group can be attached to the defined chemical structure at any heteroatom or carbon atom that results in a stable structure. Generally, heteroaryl rings do not contain O-O, S-S, or S-O bonds. However, one or more N or S atoms in a heteroaryl group can be oxidized (e.g., pyridine N-oxide thiophene S-oxide, thiophene S,S-dioxide). Examples of heteroaryl groups include, for example, the 5- or 6-membered monocyclic and 5-6 bicyclic ring systems shown below: where T is O, S, NH, N-alkyl, N-aryl, N-(arylalkyl) (e.g., N-benzyl), SiH2, SiH(alkyl), Si(alkyl)2, SiH(arylalkyl), Si(arylalkyl)2, or Si(alkyl)(arylalkyl). Examples of such heteroaryl rings include pyrrolyl, furyl, thienyl, pyridyl, pyrimidyl, pyridazinyl, pyrazinyl, triazolyl, tetrazolyl, pyrazolyl, imidazolyl, isothiazolyl, thiazolyl, thiadiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, indolyl, isoindolyl, benzofuryl, benzothienyl, quinolyl, 2-methylquinolyl, isoquinolyl, quinoxalyl, quinazolyl, benzotriazolyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxadiazolyl, benzoxazolyl, cinnolinyl, lH-indazolyl, 2H-indazolyl, indolizinyl, isobenzofuyl, naphthyridinyl, phthalazinyl, pteridinyl, purinyl, oxazolopyridinyl, thiazolopyridinyl, imidazopyridinyl, furopyridinyl, thienopyridinyl, pyridopyrimidinyl, pyridopyrazinyl, pyridopyridazinyl, thienothiazolyl, thienoxazolyl, thienoimidazolyl groups, and the like. Further examples of heteroaryl groups include 4,5,6,7-tetrahydroindolyl, tetrahydroquinolinyl, benzothienopyridinyl, benzofuropyridinyl groups, and the like. In certain embodiments, heteroaryl groups can be substituted as described herein. In certain embodiments, heteroaryl groups can be optionally substituted.

[45] The term "optionally substituted" refers to a chemical group, such as alkyl, cycloalkyl aryl, and the like, wherein one or more hydrogen may be replaced with a substituent as described herein, for example, halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamido, ketone, aldehyde, ester, heterocyclyl, 8 HK 20106287 B aromatic or heteroaromatic moieties, -CF3, -CN, or the like

[46] The term "nitro" is art-recognized and refers to -NO2; the term "halogen" is art- recognized and refers to -F, -Cl, -Br or -I; the term "sulfhydryl" is art-recognized and refers to -SH; the term "hydroxyl" means -OH; and the term "sulfonyl" and “sulfone” is art-recognized and refers to -SO2-. "Halide" designates the corresponding anion of the halogens.

[47] The present disclosure provides a method of dyeing a textile, the method comprising: depositing a MOF on at least one surface of the textile thereby forming a MOF functionalized textile; contacting the MOF functionalized textile with a dye thereby forming a dyed textile; and optionally drying the dyed textile.

[48] Advantageously, the methods described herein do not require the use of a mordant, and in particular toxic mordants comprising chromium or tin. Mordants are typically used to enhance the binding of dyes on textiles. Common inorganic mordants include salts of aluminum, iron, tin, copper, cobalt, chromium, tungsten, iodine, and the like. Exemplary inorganic mordants, include, but are not limited to, alum, ferrous sulfate, stannous chloride, copper sulfate, potassium dichromate, stannous sulfate, cobalt sulfate, aluminum sulfate, magnesium sulfate, zinc sulfate, manganese sulfate, nickel sulfate, stannic chloride, ferric chloride, aluminum chloride, copper chloride, zinc chloride, aluminum nitrate, calcium hydroxide, zinc tetrafluoroborate, zirconium oxychloride, rhenium trichloride, neodymium trichloride, lanthanum oxide, and the like. Plant-based mordants are also known in the art, such as tannic acid, Eucalyptus spp., Entada spiralis, Acacia catechu, Emblica officinalis, Memecylon scutellatum, Punica granatum, Quercus infectoria, Rhus coriaria, Rumex hymenosepolus, Tamarindus indica, Prosopis spp., Terminalia bellerica, Terminalia chebula, Enterolobium cyclocarpum, Caesalpinia coriaria, Symplococcus spp., Aporusa spp., Baccaurea racemosa, Xanthophyllum lanceatum, Eurya acuminate, Pyrus pashia, and the like

[49] The textile can be individual staple fibers or filaments, yarns, fabrics, and articles (e.g., garments). Yarns may include, for instance, multiple staple fibers that are twisted together, filaments laid together without twist, filaments laid together with a degree of twist, and a single filament with or without twist. The yarn may or may not be texturized. Suitable fabrics may likewise include, for instance, woven fabrics, knit fabrics, and non-woven fabrics. Garments 9 HK 20106287 B may be apparel and industrial garments. Fabrics and textiles may include home goods, such as linens, drapery, and upholstery (automotive, boating, airline included).

[50] The method of the present disclosure is applicable to all types of textiles, including but are not limited to synthetic fibers, such as polyester, a polyamide, a polyolefin, an acrylic, modacrylic, an acetate, a polyurethane, or combinations thereof. Exemplary synthetic fibers include, but are not limited to polyethylene terephthalate (PET), Kevlar, nomex, spandex, nylon, and the like; organic fibers, such as celluloses, such as one or more of wood, bamboo, cotton, banana, piña, hemp ramie, linen, coconut palm, soya, milk, hoya, bagasse, kanaf, retting, mudrar, silk, wool, cashmere, alpaca, angora wool, mohair, shearling, vicuña, shahtoosh, and the like; semi-synthetic fibers, such as viscose, cuprammonium, rayon, polynosic, lyocell, cellulose acetate, and the like and combinations thereof.

[51] In certain embodiments, the textile comprises cotton, a PET / cotton blend (polycotton), wool, or a combination thereof.

[52] MOFs are coordination polymers having an inorganic-organic framework comprising metal ions and organic bridging ligands between the metal ions, which can exist as two- or three-dimensional lattices in which the metal ions are bound by the organic bridging ligands. The organic ligands can be bi-, tri-, or tetra-dentate. Figure 8 depicts exemplary ligands that can be used to prepare the MOF functionalized textiles in accordance with certain embodiments described herein.

[53] Advantageously, the application of the MOF on at least one surface of the textile improves both dye uptake and colorfastness. The MOF can also impart additional functional properties to the textile, such as antibacterial and infrared protection.

[54] The application of the MOF on at least one surface of the textile can result in a MOF functionalized textile comprising the MOF deposited on at least on surface of the textile and / or in the interior of the of the functionalized textile.

[55] The MOF can comprise at least one metal ion selected from the group consisting of sodium (I), potassium (I), calcium (II), magnesium (II), aluminum (III), copper (II), zinc (II), titanium (IV), zirconium (IV), and combinations thereof. In certain embodiments, the MOF comprises aluminum (III) or zinc (II). In certain embodiments, the MOF does not comprise chromium, iron, or tin ions. 10 HK 20106287 B

[56] The MOF can comprise at least one ligand selected from the group consisting of an aryl dicarboxylate, a heteroaryl dicarboxylate, an aryl tricarboxylate, a heteroaryl tricarboxylate, an aryl tetracarboxylate, a heteroaryl tetracarboxylate, an imidazole, a benzimidazole, and conjugate acids thereof. Exemplary ligands include, but are not limited to the ligands depicted in Figure 8, such as terephthalate, isophthalate, 2-hydroxyterephthalate, 5-hydroxyisophthalate, 2-aminoterephthalate, benzene-1,3,5-tricarboxylate, benzene-1,2,4,5- tetracarboxylate, thiophene-2,5-dicarboxylate, furan-2,5-dicarboxylate, [1,1'-biphenyl]-4,4'- dicarboxylate, naphthalene-2,7-dicarboxylate, naphthalene-1,4-dicarboxylate, naphthalene- 2,6-dicarboxylate, 5'-(4-carboxylatophenyl)-[1,1':3',1''-terphenyl]-4,4''-dicarboxylate, 4,4',4''- (1,3,5-triazine-2,4,6-triyl)tribenzoate, 2-methyl-1H-imidazole, 2-ethyl-1H-imidazole, 2- methyl-1H-benzo[d]imidazole, 2-ethyl-1H-benzo[d]imidazole. In certain embodiments, the MOF comprises a ligand selected from the group consisting of benzene-1,3,5-tricarboxylate and furan-2,5-dicarboxylate. In certain embodiments, the ligand is not tartrate.

[57] In certain embodiments, the MOF comprises aluminum (III) benzene-1,3,5- tricarboxylate, zinc (II) 2,5-furandicarboxylate, or a conjugate acid thereof. In certain embodiments, the MOF is not aluminum (III) tartrate.

[58] In certain embodiments, cellulosic textiles, such as cotton and cotton blends, are first treated with citric acid in order to increase the degree of substitution (DS) thereby introducing additional carboxylic acid groups onto the surface, such that MOFs can be anchored more efficiently. In certain embodiments, the DS of the cellulosic textile after reaction with citric acid is between 0.001 and 0.5.

[59] The MOF functionalized textile can increase the uptake and colorfastness of any type of dye. As such, the dye used in the methods described herein is not particularly limited. However, given the poor uptake and color fastness of natural dyes, the methods described herein are particularly useful for natural dyes. The natural dye can be plant-derived, animal- derived, mineral-derived, or fungi-derived.

[60] The plant-derived natural dye can be derived from the plant leaves, stems, bark, roots, flowers, fruits, nuts, and the like. The plant-derived dye can be obtained from any plant species, such as indigo grass, kiai, shellfish purple, carrots, gardenia, saffron, annatto, orange, tomato, turmeric, gadgets, shoga, yellowfin, yellow lotus, large yellow, black-tailed grass, apples, 11 HK 20106287 B cherries, grapes, oyster grasshoppers, peony, roses, buzzards, carnations, kumazasa, mulberry, aloe, riyasu, bayberry, sophora, garcinia, scutellaria, chestnuts, kepracho, yasha fushiko, milobaran, catechu, pomegranate, coffee, walnut, ume, sou, logwood, and the like.

[61] Depending on the desired hue, the plant-derived natural dye can be, for example, an anthraquinone derivative, an anthocyan (such as 3,5,7-trihydroxy-2-phenylbenzobililium, anthocyanin, anthocyanidin, pelargonidin, cyanidin, peonidin, delphinidin, petunidin, malvidin and the like), a carotenoid (such as zeta-carotene), a chalcone derivative (such as, chalcone, chalcone glycoside, querchycene, cyanidin and the like), a chlorophyll derivative, a dihydropyran derivative, a diketone, a flavonoid (such as apigenin, apiin, gencanin, luteolin, baicalein, baicalin, ougonine, plantaginine, vitexin, orientin, swellticin, kaempferol, astragalin, aphzelin, quercetin, quercitrin, isoquercitrin, rutin, myricetin, morin and icariin, liquiritigenin, liquiritin, naringenin, naringin, sakuranetin, sakuranin, hesperetin, hesperidin, neohesperidin; daidzein, daidzin, puerarin, formonetin, genistin, genistin, flavan-3-ol, kaempferol, myricetin, quertisene, and the like), an indole derivative (such as indigo, indoxyl, indigo isomers, indirubin and the like), an isohinohan derivative (such as berberine, violacein, prodigiosin and the like), a naphthoquinone derivative (such as 9,10-anthraquinone, alizarin, anthraquinone-2- sulfonic acid, 2,3-dibromoanthraquinone and the like), and a tannin (such as catechin, epicatechin, epigallocatechin, ganvir tannin, gallic acid, ellagic acid, quinic acid, shikimic acid, geraniin, cinnamtannin A1 , cinnamtannin B1, and the like).

[62] Animal-derived dyes include, but are not limited to, dyes derived from cochineal, kermes, lac scale insects, tyrian purple (sea snail).

[63] Mineral-derived dyes include, but are not limited to, dyes derived from ferrous sulfate, ochre, clay, and the like.

[64] In certain embodiments, the natural dye is curcumin, madder, cochineal, lac, onion peel, indigo carmine, indigo, areca nut, black walnut, kamala, red sandal wood, or sappan wood.

[65] The MOF can be deposited on textile by contacting a solution comprising the MOF or MOF precursor(s) on the textile.

[66] In certain embodiments, the step of depositing the MOF comprises: contacting the textile with a MOF precursor solution thereby forming the MOF functionalized textile, wherein MOF precursor solution comprises: at least one metal ion selected from the group 12 HK 20106287 B consisting of magnesium (II), aluminum (III), copper (II), zinc (II), titanium (IV), and zirconium (IV); and at least one ligand selected from the group consisting of an aryl dicarboxylate, a heteroaryl dicarboxylate, an aryl tricarboxylate, a heteroaryl tricarboxylate, an aryl tetracarboxylate, a heteroaryl tetracarboxylate, an imidazole, a benzimidazole, and conjugate acids thereof.

[67] The MOF precursor solution can comprise any solvent in which the at least one metal ion and at least one ligand is at least partially soluble. In certain embodiments the MOF precursor solution comprises water.

[68] The MOF precursor solution can be prepared using the at least one ligand in deprotonated form (i.e., the conjugate acids of the recited carboxylates) or they can be prepared in situ by reacting the conjugate acids with a suitable base. Any base can be used for the in situ generation of the deprotonated ligands, such as alkali or alkaline earth hydroxides, carbonates, bicarbonates, or alkoxides, ammonia, trialkylamines, and the like.

[69] The metal ion can be present in the MOF precursor solution with one or more anions. The type of anion is not particularly limited. In certain embodiments, the anion is halide (e.g., chloride, bromide, and iodide), carbonate, bicarbonate, sulfate, phosphate, nitrate, acetate, formate, methoxide, ethoxide, isopropoxide, and the like. In certain embodiments, the at least one metal salt is zinc (II) acetate or aluminum (III) nitrate.

[70] The MOF precursor solution can comprise the at least one metal salt at a concentration between 0.1 to 0.5 M, 0.1 to 0.4 M, 0.1 to 0.3 M, 0.15 to 0.25 M, or 0.1 to 0.2 M. In certain embodiments, the MOF precursor solution comprises the metal salt at a concentration of about 0.2 M.

[71] The MOF precursor solution can comprise the at least one ligand at a concentration between 0.01 to 0.5 M, 0.01 to 0.4 M, 0.01 to 0.3 M, 0.01 to 0.2 M, 0.01 to 0.15 M, or 0.05 to 0.15 M.

[72] The step of contacting the MOF precursor solution and the textile can be conducted at any temperature between 23-90 °C.

[73] In certain embodiments, the step of depositing the MOF comprises: contacting the textile with a first solution comprising at least one metal salt and a second solution comprising at least one ligand thereby forming the MOF functionalized textile, wherein the at least one 13 HK 20106287 B metal salt comprises magnesium (II), aluminum (III), copper (II), zinc (II), titanium (IV), zirconium (IV), or a combination thereof; and the at least one ligand comprises an aryl dicarboxylate, a heteroaryl dicarboxylate, an aryl tricarboxylate, a heteroaryl tricarboxylate, an aryl tetracarboxylate, a heteroaryl tetracarboxylate, an imidazole, a benzimidazole, and conjugate acids thereof, wherein the first solution and the second solution are contacted with the textile sequentially or concurrently.

[74] The first solution and the second solution can comprise any solvent in which the at least one metal ion and at least one ligand, respectively, are at least partially soluble. In certain embodiments the first solution and the second solution comprise water.

[75] The second solution can be prepared using the at least one ligand in deprotonated form (i.e., the conjugate acids of the recited carboxylates) or they can be prepared in situ by reacting the conjugate acids with a suitable base. Any base can be used for the in situ generation of the deprotonated ligands, such as alkali or alkaline earth hydroxides, carbonates, bicarbonates, or alkoxides, ammonia, trialkylamines, and the like.

[76] The at least one metal salt can comprise one or more anions. The type of anion is not particularly limited. In certain embodiments, the anion is halide (e.g., chloride, bromide, and iodide), carbonate, bicarbonate, sulfate, phosphate, nitrate, acetate, formate, methoxide, ethoxide, isopropoxide, and the like. In certain embodiments, the at least one metal salt is zinc (II) acetate or aluminum (III) nitrate.

[77] The first solution can comprise the at least one metal salt at a concentration between 0.1 to 0.5 M, 0.1 to 0.4 M, 0.1 to 0.3 M, 0.15 to 0.25 M, or 0.1 to 0.2 M. In certain embodiments, the first solution comprises the metal salt at a concentration of about 0.2 M.

[78] The second solution can comprise the at least one ligand at a concentration between 0.01 to 0.5 M, 0.01 to 0.4 M, 0.01 to 0.3 M, 0.01 to 0.2 M, 0.01 to 0.15 M, or 0.05 to 0.15 M. In certain embodiments, the second solution comprises the at least one ligand at a concentration of about 0.1 M.

[79] The step of contacting the first solution and the second solution with the textile can each be independently conducted at any temperature between 23-90 °C.

[80] The MOF precursor solution, first solution, and second solution can be applied to the surface of the textile using any method known to those of skill in the art including, but not 14 HK 20106287 B limited to spin coating, printing, print screening, spraying, painting, doctor-blading, slot-die coating, and dip coating. The step of applying one or more of the MOF precursor solution, first solution, and second solution to the textile can optionally further comprise ultrasonication. In certain embodiments, the step of applying one or more of the MOF precursor solution, first solution, and second solution to the textile comprises dip coating and ultrasonication.

[81] The step of depositing the MOF can be repeated one or more times. In certain embodiments, the step of depositing the MOF is repeated 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more times.

[82] The textile can be optionally dried between each deposition cycle and / or between contacting the first solution and the second solution. The drying temperature can be between 23-90 °C.

[83] The MOF functionalized textile can also optionally be dried prior to dyeing. In certain embodiments, the MOF functionalized textile is dried at a temperature between 23-80 °C.

[84] The MOF functionalized textile can be dyed using any dyeing methods known to those of skill in the art. The dyeing conditions can depend on the desired hue, type of dye being employed, type of textile being dyed, etc. The selection of the appropriate dyeing conditions is well within the skill of a person of ordinary skill in the art.

[85] In certain embodiments, the MOF functionalized textile is dyed by contacting the MOF functionalized textile with an aqueous solution of the dye.

[86] The aqueous solution can comprise the dye at a concentration between 0.1 to 50 owf%, 0.1 to 40 owf%, 0.1 to 30 owf%, 0.1 to 20 owf%, or 0.5 to 20 owf%.

[87] The MOF functionalized textile can be dyed at a temperature between 23-95 °C, 40-95 °C, 50-95 °C, 60-95 °C, 70-90 °C, or 75-85 °C. In certain embodiments, the MOF functionalized textile is dyed at about 80 °C.

[88] In certain embodiments, the textile is functionalized with the MOF via a layer-by-layer approach. Metal ion and ligand are first dissolved separately in water to form the respective metal ion solution and ligand solution. The solutions are used to functionalize textile surface in the subsequent dipping cycle(s) as described as follows. In certain embodiments, the textile may be functionalized for 1 to 10 dipping cycles. For each dipping cycle, it comprises of the following steps: 15 HK 20106287 B 1. The textile is immersed in the metal ion solution under ultrasonication at room temperature for 1 – 5 minutes. 2. The textile is then dried under room temperature or inside an oven at a temperature up to 80 °C. 3. The textile is then immersed in the ligand solution under ultrasonication at room temperature for 1 – 5 minutes. 4. The textile is then dried under room temperature or inside an oven at a temperature up to 80 °C.

[89] In certain embodiments, the textile surface is functionalized with MOF by an in-situ growth approach. Metal ions and ligand ions are first dissolved together in water to form a MOF solution. The textile is then immersed in the MOF solution under ultrasonication at room temperature for 1 hour. After that, the treated textile is then dried under room temperature or inside an oven under no higher than 80 °C.

[90] EXAMPLES

[91] The present disclosure is further defined in the following Examples. It should be understood that these Examples, while indicating certain preferred embodiments of the disclosure, are given by way of illustration only. The amounts thereof, as well as the conditions elaborated should not be limited in the Examples only.

[92] EXAMPLE 1

[93] Preparation conditions of MOF-functionalized fabrics (MOF@fabrics) summarized in Table 1 were prepared and used in the subsequent Examples. To prepare the MOF@fabrics, the metal ion solutions were prepared by directly mixing zinc acetate dihydrate or aluminum nitrate nonahydrate in water at the concentration as stated in the table. To prepare 2,5- furandicarboxylic acid or benzene-1,3,5-tricarboxylic acid solution, sodium hydroxide in equivalent mole ratio to the carboxylic acid groups of the ligand was added in the aqueous mixture, in order to enhance the solubility in water by promoting deprotonation.

[94] The MOF@fabrics were prepared by layer-by-layer approach, in which the fabrics were immersed alternatively in metal ion solutions and ligand solutions twice.

[95] Table 1. Preparation conditions of MOF@fabrics. 16 HK 20106287 B MOF@ fabric ZnFDCA@ cotton MIL-96@ cotton MIL-96@ polycotton MIL-96@ wool MOF ZnFDCA MIL-96 MIL-96 MIL-96 Metal ion Zinc acetate dihydrate (0.2 M) Aluminum nitrate nonahydrate (0.2 M) Aluminum nitrate nonahydrate (0.2 M) Aluminum nitrate nonahydrate (0.2 M) Ligand 2,5- Furandicarboxyli c acid (0.1 M) Benzene-1,3,5- tricarboxylic acid (0.1 M) Benzene- 1,3,5- tricarboxylic acid (0.1 M) Benzene-1,3,5- tricarboxylic acid (0.1 M) Base Sodium hydroxide (0.2 M) Sodium hydroxide (0.2 M) Sodium hydroxide (0.2 M) Sodium hydroxide (0.2 M) Fabric Cotton Cotton Polycotton Wool Preparation method Layer-by-layer (2 dipping cycles) Layer-by-layer (2 dipping cycles) Layer-by- layer (2 dipping cycles) Layer-by-layer (2 dipping cycles)

[96] EXAMPLE 2

[97] Fourier-transform infrared spectroscopy (FTIR) spectroscopy was used to characterized the MOFs and MOF@fabrics as prepared in Example 1. In FIG. 1A, the decreased intensity of stretching peak at 3309 cm-1 of ZnFDCA@cotton implies the successful formation of coordination between ZnFDCA and cotton fabric. And the stretching peaks at 1558 cm-1 and 1360 cm-1 correspond to symmetric stretching of C-O bonded to zinc, and asymmetric stretching of C-O bonded to zinc respectively.

[98] In FIG. 1B and 1C, the reduced intensity of stretching peak at 3300 cm-1 of MIL- 96@cotton and MIL-96@polycotton implies the successful formation of coordination between MIL-96 and cotton / polycotton fabrics. Similarly, the stretching peaks at 1576cm-1 and 1388 cm-1 correspond to symmetric stretching of C-O bonded to aluminum, and asymmetric stretching of C-O bonded to aluminum respectively. 17 HK 20106287 B

[99] The FTIR spectrum of MIL-96@wool does not show characteristic peaks from MIL- 96 (FIG. 1D), probably due to overlapping of peaks from wool. The presence of Al-MOF is further confirmed in Example 3.

[100] EXAMPLE 3

[101] Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were utilized to characterize the MOF@fabrics as prepared in Example 1. In FIG. 2A to 2C, the SEM images showed the presence of MOFs distributing evenly on the fabric surface. And the presence of C, O, and Al were further confirmed by the EDX spectra, implying successful immobilization of MIL-96 onto the fabric surface.

[102] EXAMPLE 4

[103] Untreated cotton and MIL-96@cotton were dyed yellow, red and blue respectively. The fabrics were dyed at 80 °C for 1 hour in the respective aqueous dyeing bath, which consisting of the respective natural dye at 1 owf% in water without the addition of mordants or other additives. The dyed fabrics were then washed with water, and dried under room temperature. The K / S values at absorption maxima were compared in Table 2. It is obvious that the K / S value of MIL-96@cotton is 337% (curcumin - yellow), 50% (madder - red) and 372% (indigo carmine - blue) higher than those of the control cotton fabrics.

[104] Table 2. Comparison of color strength of cotton fabric and MIL-96@cotton fabric after natural dyeing. Color K / S value of dyed cotton K / S value of dyed MIL- 96@cotton Yellow (curcumin) 0.12 ± 0.01 0.50 ± 0.03 Red (madder) 0.15 ± 0.01 0.23 ± 0.01 Blue (indigo carmine) 0.15 ± 0.01 0.71 ± 0.06

[105] EXAMPLE 5 18 HK 20106287 B

[106] The colorfastness of dyed cotton and MIL-96@cotton were tested according to AATCC 100, and the results are listed as follows (Table 3). The colorfastness performance of MIL-96@cotton is maintained in most of the cases. In particular, the colorfastness to laundering is better to that of control fabric sample.

[107] Table 3. Summary of colorfastness results. Fabric Color Dyestuff concentration Colorfastness Laundering (AATCC 61) Perspiration (AATCC 15) Water (AATCC 107) Crocking (AATCC 8) Dry Wet Cotton Yellow (curcumin) 1 owf% 3.0 4.5 4.5 4.5 4.5 MIL-96 @cotton Yellow (curcumin) 1 owf% 3.5 4.5 4.5 4.5 4.5

[108] EXAMPLE 6

[109] The antibacterial tests were conducted on ZnFDCA@cotton, ZnFDCA@polycotton and ZnFDCA@wool, against S. aureus and K. pneumoniae according to AATCC 100. The percentages of reduction of bacteria are >99.99% (Table 4).

[110] Table 4. Summary of colorfastness results. MOF@fabric Percent of reduction in bacteria (AATCC 100; test bacteria: S. aureus) Percent of reduction of bacteria (AATCC 100; test bacteria: K. pneumoniae) ZnFDCA@cotton >99.99% >99.99% ZnFDCA@polycotton >99.99% >99.99% ZnFDCA@wool >99.99% >99.99%

[111] EXAMPLE 7

[112] The skin irritability of ZnFDCA@cotton, ZnFDCA@polycotton and ZnFDCA@wool were tested according to ISO 10993.10-2010. Their skin irritability was categorized as negligible. INDUSTRIAL APPLICABILITY 19 HK 20106287 B

[113] The present disclosure provides a mordant-free dyeing method for textiles, that can enhance the dyeing performance of natural dyes. With fabric surface modification by MOF prior to dyeing, the functionalized fabric can adsorb natural dyes at greater extent, leading to better dye uptake and colorfastness. Thus, the natural dyeing performance can be improved.

[114] While the present disclosure has been described and illustrated with reference to specific embodiments thereof, these descriptions and illustrations are not limiting. It should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the present disclosure as defined by the appended claims. The illustrations may not necessarily be drawn to scale. There may be distinctions between the artistic renditions in the present disclosure and the actual apparatus due to manufacturing processes and tolerances. There may be other embodiments of the present disclosure which are not specifically illustrated. The specification and the drawings are to be regarded as illustrative rather than restrictive. Modifications may be made to adapt a particular situation, material, composition of matter, method, or process to the objective, spirit and scope of the present disclosure. All such modifications are intended to be within the scope of the claims appended hereto. While the methods disclosed herein have been described with reference to particular operations performed in a particular order, it will be understood that these operations may be combined, sub-divided, or re-ordered to form an equivalent method without departing from the teachings of the present disclosure. Accordingly, unless specifically indicated herein, the order and grouping of the operations are not limitations. 20 HK 20106287 B 1 What is claimed is: 1. A method of dyeing a textile, the method comprising: depositing a metal-organic framework (MOF) comprising aluminum (III) benzene- 1,3,5-tricarboxylate on at least one surface of the textile thereby forming a MOF functionalized textile; contacting the MOF functionalized textile with a natural dye thereby forming a dyed textile; and optionally drying the dyed textile; wherein the step of depositing the MOF comprises: contacting the textile with a first solution comprising a metal ion, wherein the metal ion is aluminum (III); and contacting the textile with a second solution comprising a ligand, wherein the ligand is benzene-1,3,5-tricarboxylate or a conjugate acid thereof; wherein the second solution comprises the ligand in deprotonated form; wherein the step of depositing the MOF further comprises immersing the textile alternatively in the first solution and the second solution; and wherein the step of depositing the MOF is repeated one or more times. 2. The method of claim 1, wherein the method does not comprise a mordant. 3. The method of claim 1, wherein the first solution and the second solution are contacted with the textile sequentially. 4. The method of claim 1, wherein the first solution comprises the metal ion at a concentration between 0.1 to 0.5 M and the second solution comprises the ligand at a concentration between 0.05 to 0.5 M. 5. The method of claim 1, wherein the step of depositing the MOF further comprises ultrasonication. 6. The method of claim 1, further comprising the step of contacting the textile with citric acid prior to the step of depositing the MOF. HK 20106287 B 2 7. The method of claim 1, wherein the textile comprises cotton, wool, or polycotton. 8. The method of claim 1, wherein the MOF functionalized textile is contacted with an aqueous solution of the natural dye at a temperature between 40-95 °C. 9. The method of claim 8, wherein the aqueous solution comprises the natural dye at 0.5 to 20 on-weight-fabric (owf)%. 10. The method of claim 1, wherein the textile comprises cotton. 11. The method of claim 1, wherein the step of contacting the textile with the first solution and the second solution further comprises ultrasonication. 12. The method of claim 1, wherein the MOF functionalized textile is contacted with an aqueous solution of the natural dye at a temperature between 70-90 °C, wherein the aqueous solution comprises the natural dye at 0.5 to 20 on-weight-fabric (owf)%. 13. The method of claim 1, wherein the natural dye comprises curcumin, madder, cochineal, lac, onion peel, indigo carmine, indigo, areca nut, black walnut, kamala, red sandal wood, or sappan wood. 14. The method of claim 1, wherein the method further comprises deprotonating the ligand in the second solution by adding to the second solution a base in an amount equivalent to at least one carboxylic acid group of the ligand, thereby forming at least one deprotonated carboxylate group. 15. The method of claim 4, wherein the first solution comprises the metal ion at a concentration of about 0.2 M and the second solution comprises the ligand at a concentration of about 0.1 M. 16. A dyed textile prepared according to the method of claim 1. HK 20106287 B 1 / 4 FIG. 1 FIG. 2 HK 20106287 B 2 / 4 FIG. 3 FIG. 4 HK 20106287 B 3 / 4 FIG. 5 FIG. 6 FIG. 7 HK 20106287 B 4 / 4 FIG. 8 HK 20106287 B

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