Method of treating a material

Abstract

The present invention provides a method of treating a material with water- insoluble particles, the method comprising: (a) providing a suspension of water-insoluble particles in water; (b) applying the suspension of water-insoluble particles to the material; (c) applying a chitosan solution to the material to obtain treated material; and (d) drying the treated material at a temperature not exceeding 100 0C, preferably at a temperature of less than 70 0C, wherein the material comprises textile, preferably fabric, yarn, and / or fibre.

Description

[0001] Method of Treating a Material

[0002] INTRODUCTION

[0003] The present invention relates to a method of treating a material with waterinsoluble particles, to uses of the method, and to materials obtained or obtainable by the method.

[0004] BACKGROUND

[0005] There is frequently a need in the textile industry to treat materials with certain particles, in order to impart desired properties to the materials and the textile articles resulting therefrom. However, challenges arise when the particles of interest are waterinsoluble, which makes it harder to promote association of the particles with the material structure and to achieve the desired treatment result.

[0006] Traditional methods known in the art have focused on solubilising the particles before the treatment of the material. However, such methods generate very large amounts of highly coloured polluted waste water. Alternative methods have been associated with energy-intensive, high-temperature curing steps, also having a negative environmental impact.

[0007] For example, there is a particular want for a more sustainable method for dyeing denim materials with indigo. The standard process is very polluting, due to the intensive chemistry of indigo reduction needed to solubilise the indigo dye, with large amounts of waste-water also generated.

[0008] Green Chem., 2021 , 23, 7937-7944 proposed the use of nanofibrillar cellulose (NFC) as a mesh to entrap indigo dye particles, followed by a chitosan treatment and high temperature curing (150 °C). It is proposed that the NFC forms a mesh around the particles and that chitosan strengthens the NFC network. However, this method requires the use of energy-intensive, high-temperature curing, as well as the use of additive polymers. US9506187 similarly relates to a method of dyeing a material using a dyed nanocellulose dispersion, though without disclosure of a chitosan treatment. This method again suffers from a need for additive polymers.

[0009] There therefore exists a need for a greener, more sustainable method of material treatment when using water-insoluble particles. The method should lead to effective, long-lasting treatment of materials, ideally with a diverse range of particle types.

[0010] SUMMARY OF THE INVENTION

[0011] 15029876-2 Viewed from a first aspect, the present invention provides a method of treating a material with water-insoluble particles, the method comprising:

[0012] (a) providing a suspension of water-insoluble particles in water;

[0013] (b) applying the suspension of water-insoluble particles to the material;

[0014] (c) applying a chitosan solution to the material to obtain treated material; and

[0015] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein the material comprises textile, preferably fabric, yarn, and / or fibre.

[0016] Viewed from a further aspect, the present invention provides use of a method as hereinbefore described to impart colour to a material, to colour a material, and / or to dye a material.

[0017] Viewed from a further aspect, the present invention provides use of a method as hereinbefore described to apply antioxidant to a material, or to impart antioxidant activity to a material.

[0018] Viewed from a further aspect, the present invention provides a material obtained or obtainable, preferably obtained, by a method as hereinbefore described.

[0019] DEFINITIONS

[0020] As used herein, the “treating” of a material with particles refers to the association of the particles with the material and / or to the imparting of certain properties to the material by the particles.

[0021] As used herein, the term “fibres” refers to material in a form wherein its length is significantly longer than its width.

[0022] As used herein, the term “yarn” refers to material wherein one or more fibres are interlocked. This term encompasses thread.

[0023] As used herein, the term “fabric” refers to material constructed from fibres, yarn or combinations thereof. A fabric may be woven or unwoven. It may be knitted.

[0024] As used herein, the term “textile” encompasses fibres, yarn, and fabric.

[0025] As used herein, the term “suspension” refers to a liquid in which undissolved solid particles are present, e.g. in which undissolved solid particles are dispersed.

[0026] As used herein, the term “water-insoluble particles” refers to particles which form a suspension in water, e.g. at room temperature and atmospheric pressure. Preferred levels of solubility are given below. Water-solubility can preferably be determined using ISO 787-8, especially for pigments and fillers.

[0027] 15029876-2 As used herein, the term “colour-agent” encompasses dyes and pigments. It will be understood that particles of colour-agent to be used in the present invention are water-insoluble.

[0028] As used herein, the term “ambient” temperature preferably refers to a temperature in the range of 10 to 35 °C, preferably about 25 °C.

[0029] DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention provides a method of treating a material with waterinsoluble particles, the method comprising:

[0031] (a) providing a suspension of water-insoluble particles in water;

[0032] (b) applying the suspension of water-insoluble particles to the material;

[0033] (c) applying a chitosan solution to the material to obtain treated material; and

[0034] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein the material comprises textile, preferably fabric, yarn, and / or fibre.

[0035] It has been found that the method of the present invention leads to effective treatment of such materials with water-insoluble particles, including with a variety of colour-agent particles and antioxidant particles. Treatment is long-lasting and shows strong resistance to washing.

[0036] Surprisingly, neither the addition of polymer agents nor the use of high temperature curing steps was found to be required in the method, offering the possibility of a more environmentally-friendly method. The efficacy of the method with particle suspensions also obviates the need to dissolve the particles, offering a greener process which avoids the need for chemically intensive solubilisation steps.

[0037] Material

[0038] The method of the present invention is a method of treating a material. The material comprises textile, preferably fabric, yarn, and / or fibre. The material may preferably consist of, or consist essentially of, textile, which may in turn preferably consist of, or consist essentially of, fabric, yarn, and / or fibre. The material preferably is a textile, and more preferably is a fabric, yarn, and / or fibre or fibres.

[0039] Textile, in particular fabric and yarn, are particularly preferred. It will be understood that cloth, thread, string, twine, fibre strands and other fibre structures, and other forms of material, are encompassed by the material of the present invention.

[0040] 15029876-2 Materials for use in the method may preferably be selected from those suitable for use in the textile industry or for use in textile applications, for example in the fashion industry. The material may be a textile article. Materials may be woven or un-woven. Materials may be knitted.

[0041] The material may be a natural material, a synthetic material, or a semi-synthetic material, preferably a natural material. In other words, the material may be derived from, or may comprise, natural fibres, synthetic fibres, or semi-synthetic fibres, preferably natural fibres.

[0042] In the present invention, fibres are preferably textile fibres.

[0043] Example materials include cellulose, protein fibre, mineral fibre, and / or petroleum-based materials, preferably selected from cotton, nylon, polyester, wool, silk, and / or linen materials. Accordingly, textiles - preferably yarns, fabrics, and / or fibres - of these materials may be used. Particularly preferred materials are cellulose materials, in particular cotton cellulose materials, a preferred example of which is denim. For example, the material may comprise, or may be, denim textile, more preferably denim fabric or yarn. The treatment of denim with water-insoluble particles, in particular the dyeing of denim with indigo, has traditionally been associated with chemically-intensive solubilisation steps, creating a particular need for a greener, more sustainable method.

[0044] Particles

[0045] The method of the present invention treats a material with water-insoluble particles. It has been found that the method of the present invention yields effective results when using a diverse range of different types of water-insoluble particles. Preferred examples of water-insoluble particles are water-insoluble colour-agent, antioxidant, drug (e.g. synthetic drugs), enzyme (e.g. immobilised enzyme), and / or bioactive (e.g. plant-based bioactives) particles, more preferably water-insoluble colouragent and / or antioxidant particles.

[0046] As mentioned, the water-insoluble particles may be water-insoluble drug and / or bioactive particles, preferably water-insoluble drug particles. Treatment of materials using the method of the present invention may desirably allow such particles to be released slowly from, or consumed slowly on, the material over time, for example enabling the treated material to provide a therapeutic or prophylactic effect over time. Drugs may, for example, be a natural product or, preferably, a synthetic drug. Preferred examples of drugs include antimicrobials, for example antibiotics, antifungals, and / or antivirals. Such examples may desirably reduce the ability of the material to carry

[0047] 15029876-2 pathogens, or may provide a barrier between the user of the material and pathogens. Another preferred example of a drug is an anti-inflammatory. A preferred example of a bio-active is powdered frankincense, which may be rich in bioactive boswellic acids, and / or antimicrobial bioactives, such as those which are plant-derived. The particles may also be water-insoluble pesticide particles, which may be of particular use if the material is to form a bag or sack for applications in which pests should be avoided.

[0048] The water-insoluble particles may be water-insoluble enzyme particles (e.g. particles of immobilised enzyme). The use of such particles may be useful in the preparation of biocatalytic materials.

[0049] Particularly preferred water-insoluble particles are water-insoluble colour-agent and / or antioxidant particles.

[0050] Preferably, the water-insoluble particles are water-insoluble colour-agent particles. In such a case, the method can be considered a method of imparting colour to the material, of colouring the material, and / or of dyeing the material. The use of waterinsoluble colour-agent particles advantageously allows the material to be imparted with a desired colour, which has been found to be long-lasting and resilient to washing. The particles may, for example, be water-insoluble colour pigment and / or dye particles. As with all particles in the present invention, the colour-agent may be organic or inorganic.

[0051] Preferred examples of colour-agents are natural or synthetic indigo, red or yellow iron oxide, charcoal (e.g. particles of micronised charcoal), disperse dyes / pigments (e.g disperse blue (e.g. disperse blue 56), disperse red (e.g. disperse red 1), disperse yellow (e.g. disperse yellow 3), disperse orange (e.g. disperse orange 25), disperse violet (e.g. disperse violet 1), disperse brown (disperse brown 27), and / or disperse black (e.g. disperse black 9)), vat dyes / pigments (e.g. vat blue (e.g. vat blue 1 or), and / or vat green (e.g. vat green 1)), and / or indanthrone blue.

[0052] Particularly preferred examples of colour-agent are natural or synthetic indigo, red or yellow iron oxide, and / or charcoal (e.g. particles of micronised charcoal). More preferably, the colour-agent is natural or synthetic indigo. The treatment of materials with indigo is particularly desired in the fashion industry, for example to colour materials such as denim. The treatment of materials with indigo has traditionally been associated with chemically-intensive solubilisation steps, creating a particular need for a greener, more sustainable method.

[0053] Preferably, the water-insoluble particles are water-insoluble antioxidant particles. In such a case, the method can be considered a method of applying antioxidant to the material, and / or of imparting antioxidant activity to the material. Treatment of a material

[0054] 15029876-2 with such particles may thus impart the material with antioxidant properties. This offers the possibility of protecting the material from oxidative damage and / or of protecting and enhancing skin health in cosmetotextile applications. Treatment using the method of the present invention has been found to be long-lasting and resistant to washing.

[0055] Antioxidants may be natural or synthetic antioxidants. Preferred examples include: curcumin, quercetin, resveratrol, naringenin, lycopene, beta-carotene, lutein, zeaxanthin, astaxanthin, carnosic acid, ellagic acid, tocopherol (vitamin e), tocotrienol, silymarin, rosmarinic acid, piperine, butylated hydroxytoluene (bht), butylated hydroxyanisole (bha), propyl gallate, tert-butylhydroquinone (tbhq), Irganox (e.g. Irganox 1010, Irganox 1076, Irganox 1098, Irganox 245, Irganox 1035, Irganox 3114), and / or Cyanox (e.g. Cyanox 1790, Cyanox 425, Cyanox 2246). Other preferred examples include micronized plant parts, for example turmeric, which may be used for poulticetype applications.

[0056] Particularly preferred antioxidants are quercetin and resveratrol.

[0057] The particles used in the present invention are water-insoluble, as defined above. The particles are preferably water-insoluble at room temperature, more preferably at 25 °C. The particles are preferably water-insoluble at atmospheric pressure, more preferably at 1 atm of pressure.

[0058] The particles preferably have a water solubility of less than 100 mg / L, more preferably less than 75 mg / L, still more preferably less than 50 mg / L, still more preferably less than 35 mg / L, still more preferably less than 10 mg / L, still preferably less than 5 mg / L, most preferably less than or equal to 1 mg / L. Preferably, the particles have a watersolubility of greater than 0.01 mg / L, more preferably greater than 0.05 mg / L, still more preferably greater than 0.1 mg / L, still more preferably greater than 0.25 mg / L, still more preferably greater than 0.5 mg / L. The aforementioned solubility values are preferably to be taken at room temperature (e.g. 25 °C) and atmospheric pressure (e.g. 1 atm of pressure).

[0059] Water-solubility is preferably determined using ISO 787-8, especially for pigments and fillers.

[0060] The particles may optionally be coated with a substance, e.g. a wax, for reducing their water solubility.

[0061] Suspension

[0062] The method of the present invention comprises a step (a) of providing a suspension of water-insoluble particles in water. Such a step may involve providing a

[0063] 15029876-2 pre-prepared suspension, although such a step preferably comprises preparing the suspension.

[0064] Preparing a suspension of water-insoluble particles in water may comprise adding the particles to water and / or preferably mixing the particles in water.

[0065] Without wishing to be bound by any theory, it is thought that a reduction in particle size may contribute to a more rapid treatment of the material, and a treatment which is more resistant to washing. Accordingly, the method preferably comprises a step which reduces the size of the particles in the suspension. The method preferably comprises subjecting the particles to milling (e.g. jet milling and / or ball milling) high pressure homogenisation, spray drying, and / or sonication.

[0066] It has been found that treating particles using sonication leads to more rapid treatment of the material, and leads to treatment which is more resistant to washing. Without wishing to be bound by any theory, it is thought that this effect may relate to a reduction in particle size. Accordingly, the method preferably comprises sonicating the particles in water, the sonication preferably being an ultra-sonication, more preferably a low power ultra-sonication. Sonication may, for example, be at a power density of 0.01 1 W / ml, preferably 0.025 to 0.5 W / ml, more preferably 0.05 to 0.25 W / ml, still more preferably 0.06 to 0.15 W / ml, still more preferably 0.075 to 0.125 W / ml, e.g. about 0.1 W / ml.

[0067] The use of nanoparticles in material treatment can undesirably be associated with safety concerns, which can be avoided by preparing a suspension of larger particles. The particles in the suspension are therefore preferably not nanoparticles. In other words, the particles are preferably larger than nanoparticles, e.g. having an average diameter of at least 1 micrometre.

[0068] Instead, the particles in the suspension are preferably micrometre-scale particles. For example, the particles preferably have an average diameter of between 1 to 100 micrometres, more preferably 1 to 50 micrometres, still more preferably 1 to micrometres, still more preferably 1 to 10 micrometres. Methods of measuring average diameter are known to those skilled in the art, including microscopy, laser diffraction, and / or dynamic light scattering.

[0069] The suspension may consist essentially, or consist, of the particles and water. Alternatively, the suspension may comprise one or more additives, which may include surfactants, cross-linkers (e.g glutaraldehyde), and / or genipin (which may serve to enmesh the chitosan).

[0070] 15029876-2 The suspension may comprise an additive polymer, such as starch polymer, a nanocellulose, nanofibrillated cellulose (NFC), and / or carboxymethyl cellulose. However, it has surprisingly been found that the method of the present invention does not require an additive polymer to achieve effective material treatment. It is therefore preferred that the suspension does not comprise an additive starch, nanocellulose, nanofibrillated cellulose (NFC), or carboxymethyl cellulose polymer, more preferably wherein the suspension does not comprise an additive polymer. For example, the suspension may preferably comprise such additives in an amount of less than 1 %, more preferably less than 0.5 %, still more preferably less than 0.1 %, still more preferably less than 0.05 %, still more preferably less than 0.01 %, still more preferably about 0 %, most preferably 0 % w / v, based on the volume of the suspension.

[0071] Preferably, the suspension and / or the chitosan solution does not comprise an additive starch, nanocellulose, nanofibrillated cellulose (NFC), or carboxymethyl cellulose polymer, more preferably wherein the suspension and / or the chitosan solution does not comprise an additive polymer. For example, the suspension and / or the chitosan solution may preferably comprise such additives in an amount of less than 1 %, more preferably less than 0.5 %, still more preferably less than 0.1 %, still more preferably less than 0.05 %, still more preferably less than 0.01 %, still more preferably about 0 %, most preferably 0 % w / v, based on the volume of the suspension and / or the chitosan solution.

[0072] The amount of particles in the suspension can be adjusted by the skilled person. A balance will need to be struck between having sufficient particles present to achieve the desired degree of treatment, without making the suspension too viscous to handle. The suspension preferably comprises greater than 0.5 %, preferably greater than 1 %, more preferably greater than 2 %, still more preferably greater than or equal to about 2.5 % w / v of the particles, based on the volume of the suspension. The suspension preferably comprises less than 20 %, more preferably less than 10 %, still more preferably less than 7.5 %, still more preferably less than 6.5 % w / v of the particles, based on the volume of the suspension. The suspension preferably comprises between 0.5 to 10 %, preferably 1.5 to 7.5 %, more preferably 2 to 6.5 % w / v of the particles, based on the volume of the suspension.

[0073] It is preferred that step (a) is conducted at a temperature of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred step (a) is conducted at a temperature of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or

[0074] 15029876-2 equal to, e.g. less than, about 25 °C. It is preferred that step (a) is conducted at room temperature, or ambient temperature.

[0075] For example, the suspension is preferably provided at a temperature of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. The suspension is preferably provided at a temperature of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that the suspension is provided at room temperature, or ambient temperature

[0076] When the suspension is prepared, it is preferred that the preparation is conducted at temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that the preparation is conducted at temperatures of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that the preparation is conducted at room temperature, or ambient temperature.

[0077] The method of the present invention comprises a step (b) of applying the suspension of water-insoluble particles to the material. This step has a purpose of enabling the treatment of the material with the particles in the suspension. Application can be by any method, including by brushing and / or by immersing, preferably by immersing. The application can be to the whole of the material, or to just a part of the material which is desired to be treated. Following application, excess suspension can be removed, e.g. by brushing, by use of a roller, and / or by sponging.

[0078] It is preferred that step (b) is conducted at a temperature of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred step (b) is conducted at a temperature of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that step (b) is conducted at room temperature, or ambient temperature. It is preferred that applying the suspension does not comprise heating steps, e.g. to the afore-mentioned temperatures. For example, it is preferred that the suspension is not heated (e.g. to the afore-mentioned temperatures) and / or that the material is not heated (e.g. to the afore-mentioned temperatures).

[0079] 15029876-2 Chitosan

[0080] The method of the present invention makes use of a chitosan solution. The method can therefore be considered to involve the provision of a chitosan solution.

[0081] The chitosan solution may be provided as a pre-prepared solution, or the method may comprise preparing a chitosan solution. The chitosan is preferably substantially entirely dissolved. The chitosan solution is preferably a solution of chitosan in water, i.e. an aqueous solution of chitosan.

[0082] Preferably, the chitosan solution comprises 0.25 to 10 %, preferably 0.5 to 5 %, still more preferably 0.75 to 2 %, e.g. about 1 % w / v chitosan, based on the total volume of the solution. The chitosan solution preferably comprises less than 5 %, preferably less than 2.5 %, more preferably less than 2 %, still more preferably less than 1.5 % w / v chitosan, based on the total volume of the solution. The chitosan solution preferably comprises greater than 0.25 %, preferably greater than 0.5 %, more preferably greater than 0.75 % chitosan, based on the total volume of the solution.

[0083] The viscosity of the chitosan solution can be controlled by the skilled person. It may be desirable to ensure that the viscosity is sufficient to achieve effective association of the chitosan with the material, without being too viscous to handle or prepare. Preferably, the chitosan solution has a viscosity of greater than 20 cps, more preferably greater than 100 cps, still more preferably greater than 200 cps, still more preferably greater than 300 cps, still more preferably greater 400 cps. Preferably, the chitosan solution has a viscosity of less than 5000 cps, more preferably less than 2500 cps, still more preferably less than 1000 cps, still more preferably less than 800 cps. Preferably, the chitosan solution has a viscosity of between 100 to 5000 cps, more preferably 250 to 1000 cps, still more preferably 300 to 800 cps, still more preferably 400 to 750 cps.

[0084] Viscosity values, including those aforementioned, can be measured according to the method given in https: / / doi.Org / 10.1016 / i.lwt.2013.07.013. They are preferably to be taken at 24 + 0.5 °C. A viscometer may be used, e.g. at 20 rpm, using an RV-I spindle.

[0085] The chitosan solution may be homogenised, e.g. by spinning, preferably at an rpm of greater than 10,000. This may contribute to more uniform treatment of the material.

[0086] The chitosan solution may consist essentially, or consist, of chitosan in water. Alternatively, the chitosan solution may comprise one or more additional additives. It is preferred that the solution is an acidic solution, preferably having a pH of between 4 to 7, more preferably between 5 to 6. This may assist in the solubilisation of the chitosan,

[0087] 15029876-2 especially if chitosan in a free amine form is used. The solution preferably includes one or more acids, more preferably one or more weak acids, e.g. a carboxylic acid such as acetic acid.

[0088] The chitosan may be modified or unmodified chitosan. The chitosan preferably has a high degree of deacetylation, preferably greater than 50%, more preferably greater than 60%, still more preferably greater than 70%, still more preferably greater than 80% deacetylation. It is preferred that the chitosan has free -NH2 groups, and / or that the chitosan comprises modified -OH and / or modified NH2 groups.

[0089] Preferably, the chitosan is provided as a water-soluble salt, e.g. a chloride salt (e.g. an HCI salt), an acetate salt, and / or a formate salt, preferably a chloride salt (e.g. an HCI salt) and / or an acetate salt. This may improve the solubility of the chitosan solution.

[0090] The chitosan is preferably bio-derived chitosan, e.g. plant-derived or animal- derived, more preferably crustacean-derived or mushroom-derived. Obtaining chitosan from such renewable sources improves the potential sustainability of the method of the present invention.

[0091] The method of the present invention comprises a step (c) of applying the chitosan solution to the material to obtain treated material. Such a step has been found to be important in providing effective treatment of the material. As with step (b), application can be by any method, including by brushing and / or by immersing, preferably by immersing. The application can be to the whole of the material, or to just a part of the material which is desired to be treated. It will be understood that application should be to the same area to which the suspension is applied. Following application, excess solution can be removed, e.g. by brushing, by use of a roller, and / or by sponging.

[0092] It is preferred that step (c) is conducted at a temperature of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred step (c) is conducted at a temperature of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that step (c) is conducted at room temperature, or ambient temperature. It is preferred that applying the chitosan solution does not comprise heating steps, e.g. to the afore-mentioned temperatures. For example, it is preferred that the chitosan solution is not heated (e.g. to the aforementioned temperatures) and / or that the material is not heated (e.g. to the aforementioned temperatures).

[0093] 15029876-2 For example, the chitosan solution is preferably provided at a temperature of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. The chitosan solution is preferably provided at a temperature of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that the chitosan solution is provided at room temperature, or ambient temperature

[0094] When the chitosan solution is prepared, it is preferred that the preparation is conducted at temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that the preparation is conducted at temperatures of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that the preparation is conducted at room temperature, or ambient temperature.

[0095] Steps

[0096] The method of the present invention comprises a step (d) of drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C. Preferably, this temperature is less than 100 °C. This step has a purpose of drying the treated material following the application of the suspension and chitosan solution. It has surprisingly been found that the method of the present invention does not require high temperatures, e.g. high temperature curing, to achieve effective treatment. This means that a greener method can be provided, without compromising treatment performance. The avoidance of high temperatures also means that any damage to the material and / or to the properties of the particles can advantageously be avoided.

[0097] It is preferred that the treated material is dried at a temperature of less than 90 °C, more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less than 60 °C. It is preferred that the treated material is dried at a temperature of less than 50 °C, more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, 25 °C. It is preferred that the treated material is dried at a temperature of less than 70 °C.

[0098] It is preferred that the treated material is dried at a temperature not exceeding 50 °C, more preferably not exceeding 35 °C, still more preferably not exceeding 30 °C, still more preferably not exceeding about 25 °C.

[0099] 15029876-2 It is preferred that, during the step (d) of drying, the material is submitted only to temperatures of less than 100 °C, preferably less than 90 °C, more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less than 60 °C. It is preferred that, during the step (d) of drying, the material is not submitted to temperatures exceeding 100 °C, preferably not exceeding 50 °C, more preferably not exceeding 35 °C, still more preferably not exceeding 30 °C, still more preferably not exceeding about 25 °C. It is preferred that, during the step (d) of drying, the material is submitted only to temperatures of less than 100 °C, preferably less than 50 °C, more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is particularly preferred that drying is at room temperature, or at ambient temperature. This further reduces the energy consumption, and thus environmental impact, of the method of the present invention.

[0100] It is preferred that the material is not submitted to temperatures exceeding 100 °C, more preferably not exceeding 50 °C, still more preferably not exceeding 35 °C, still more preferably not exceeding 30 °C, still more preferably not exceeding about 25 °C. It is preferred that the material is submitted only to temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that the material is submitted only to temperatures of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C.

[0101] It is preferred that during the method the material is submitted only to temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that during the method the material is submitted only to temperatures of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that during the method the material is not submitted to temperatures exceeding 100 °C, more preferably not exceeding 50 °C, still more preferably not exceeding 35 °C, still more preferably not exceeding 30 °C, still more preferably not exceeding about 25 °C.

[0102] It is particularly preferred that the material is not submitted to temperatures exceeding room temperature, or ambient temperature. It is preferred that the material is kept at room or ambient temperature. It is preferred that the method does not comprise heating the material, the suspension, and / or the chitosan solution, e.g. to the

[0103] 15029876-2 aforementioned temperatures or otherwise. It is particularly preferred that during the method the material is not submitted to temperatures exceeding room temperature, or ambient temperature. It is preferred that during the method the material is kept at room or ambient temperature. It is preferred that the method does not comprise heating the material, the suspension, and / or the chitosan solution, e.g. to the aforementioned temperatures or otherwise.

[0104] For example, it is preferred that during each of steps (b), (c), and (d) the material is submitted only to temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that during each of steps (b), (c), and (d) the material is submitted only to temperatures of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that during each of steps (b), (c), and (d) the material is not submitted to temperatures exceeding room temperature, or ambient temperature. It is preferred that during each of steps (b), (c), and / or (d) the material is kept at room temperature or ambient temperature. It is preferred that the method does not during each of steps (a), (b), (c), and (d) comprise heating the material, the suspension, and / or the chitosan solution, e.g. to the aforementioned temperatures.

[0105] It is preferred that each of steps (a), (b), (c), and (d) are conducted at temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that each of steps (a), (b), (c), and (d) are conducted at temperatures of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that each of steps (a), (b), (c), and (d) are conducted at temperatures not exceeding room temperature, or ambient temperature. It is preferred that each of steps (a), (b), (c), and (d) are conducted at room temperature or ambient temperature. It is preferred that the method does not comprise heating the material, the suspension, and / or the chitosan solution, e.g. to the aforementioned temperatures.

[0106] It is preferred that during and between each of steps (a), (b), (c), and (d) the material is submitted only to temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that during and between each of steps (a), (b), (c), and / or (d) the material is submitted only to temperatures of less than 100 °C, more

[0107] 15029876-2 preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that during and between each of steps (a), (b), (c), and / or (d) the material is not submitted to temperatures exceeding room temperature, or ambient temperature. It is preferred that during and between each of steps (a), (b), (c), and (d) the material is kept at room temperature or ambient temperature. It is preferred that the method does not during and between each of steps (a), (b), (c), and / or (d) comprise heating the material, the suspension, and / or the chitosan solution, e.g. to the aforementioned temperatures.

[0108] It is preferred that the method does not comprise a step of drying, curing, heating or baking the material at a temperature of greater than 90 °C, more preferably at a temperature of greater than 80 °C, still more preferably at a temperature of greater than 70 °C, still more preferably at a temperature of greater than 60 °C. It is preferred that the method does not comprise a step of drying, curing, heating or baking the material at a temperature of greater than 50 °C, more preferably at a temperature of greater than 40 °C, still more preferably at a temperature of greater than 30 °C, still more preferably at a temperature of greater than 25 °C. It is preferred that the method does not comprise a step of drying, curing, heating, or baking the material at a temperature of greater than room or ambient temperature.

[0109] It is preferred that the method does not comprise a step of drying, curing, heating, or baking the material during, between, or after any of steps (a), (b), (c), or (d) at a temperature of greater than 90 °C, more preferably at a temperature of greater than 80 °C, still more preferably at a temperature of greater than 70 °C, still more preferably at a temperature of greater than 60 °C. It is preferred that the method does not comprise a step of drying, curing, heating, or baking the material during, between, or after any of steps (a), (b), (c), or (d) at a temperature of greater than 50 °C, more preferably at a temperature of greater than 40 °C, still more preferably at a temperature of greater than 30 °C, still more preferably at a temperature of greater than 25 °C. It is preferred that the method does not comprise a step of drying, curing, heating, or baking the material during, between, or after any of steps (a), (b), (c), or (d) at a temperature of greater than room or ambient temperature.

[0110] It is preferred that during the whole method the material is submitted only to temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that during the whole method the material is submitted only to temperatures

[0111] 15029876-2 of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that during the whole method the material is not submitted to temperatures exceeding room temperature, or ambient temperature. It is preferred that during the whole method the material kept at room temperature or ambient temperature. It is preferred that during the whole method neither the material, the suspension, and / or the chitosan solution is heated, e.g. to the aforementioned temperatures or otherwise.

[0112] It is preferred that the whole method is conducted at temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C. It is preferred that the whole method is conducted at temperatures of less than 100 °C, more preferably less than 50 °C, still more preferably less than 35 °C, still more preferably less than 30 °C, still more preferably less than or equal to, e.g. less than, about 25 °C. It is preferred that the whole method is conducted at temperatures not exceeding room temperature, or ambient temperature. It is preferred that the whole method is conducted at room temperature or ambient temperature. It is preferred that during the whole method neither the material, the suspension, and / or the chitosan solution is heated, e.g. to the aforementioned temperatures or otherwise.

[0113] The steps of the present invention may, for example, be conducted at temperatures of greater than 10 °C, greater than 15 °C, or greater than 20 °C.

[0114] It has been found that the method of the present invention offers effective treatment performance, without the need for conventional chemically-intensive particle solubilisation. Preferably, the method of the present invention therefore does not comprise the reduction and / or oxidation of the particles. Preferably, the method of the present invention does not comprise a step of solubilising the particles in water.

[0115] It has been found that the ordering of steps (b) and (c) has an impact on treatment performance. It has been found that the step (c) of applying chitosan solution occurring after, preferably immediately after, the step (b) of applying the suspension leads to improved treatment performance. Meanwhile, it has been found that step (b) and step (c) occurring simultaneously, in other words the chitosan solution and the suspension being applied to the material simultaneously, also offers effective treatment performance.

[0116] It is therefore preferred that: the step (c) of applying chitosan solution occurs after, preferably immediately after, the step (b) of applying the suspension; or step (b) and step (c) occur simultaneously, in other words that the chitosan solution and the

[0117] 15029876-2 suspension are applied to the material simultaneously. More preferably, the step (c) of applying chitosan solution occurs after, preferably immediately after, the step (b) of applying the suspension.

[0118] The step (b) of applying the suspension could instead occur after, preferably immediately after, the step (c) of applying chitosan solution. However, as this was found to offer reduced treatment performance, it is preferred that the steps are not performed in this order.

[0119] In the method of the present invention, each of steps (b), (c), and (d) may be performed once or may be performed a plurality of times, in any order. Some preferred examples of such orderings are as follows: after the step (d) of drying the treated material, steps (b) to (d) may be repeated; after the step (d) of drying the treated material, steps (c) to (d) may be repeated; and / or after the step (d) of drying the treated material, step (b) and step (d) may be repeated, optionally followed by steps (c) and (d) being repeated.

[0120] The method may be employed on just one type of particle, or on a plurality of (i.e. two or more) different particle types. As non-limiting examples, the method may treat the material with a plurality of different colour-agents, with a plurality of different antioxidants, or with a colour-agent and an antioxidant.

[0121] Where a plurality of different particle types are employed, the material may be treated with each particle type sequentially, separately, or simultaneously.

[0122] For example, the suspension provided in step (a) may comprise a plurality of different types of water-insoluble particles. In other words, the suspension may comprise at least a first type of water-insoluble particle and a second type of water-insoluble particle.

[0123] Alternatively, the method may comprise providing a plurality of suspensions of water-insoluble particles in water, each suspension comprising a different composition of water-insoluble particles, and performing a step (b) with each suspension.

[0124] Uses

[0125] The present invention also relates to the use of a method as hereinbefore described to impart colour to a material, to colour a material, and / or to dye a material. In such a case, as hereinbefore described, the particles are preferred to be particles of a colour-agent.

[0126] 15029876-2 The present invention also relates to the use of a method as hereinbefore described to apply antioxidant to a material, and / or to impart antioxidant activity to a material. In such a case, as hereinbefore described, the particles are preferred to be particles of an antioxidant.

[0127] The uses hereinbefore described are to be applied to a material comprising textile, preferably fabric, yarn, and / or fibre, as hereinbefore discussed.

[0128] The present invention also relates to a material obtained or obtainable, preferably obtained, by a method as hereinbefore described. Such a material benefits from a treatment by the particles, which is desirably long-lasting and resistant to washing. The material may subsequently be formed into an article, preferably a textile article, for example garments, furnishings, bedding, curtains, towels, medical dressings (e.g. bandages or treatment patches), sacks, and / or bags.

[0129] Preferred Methods

[0130] Some preferred methods of the present invention are as follows.

[0131] A method of imparting colour to a material, colouring a material, and / or dyeing a material, the method comprising:

[0132] (a) providing a suspension of water-insoluble colour-agent particles in water;

[0133] (b) applying the suspension of water-insoluble particles to the material;

[0134] (c) applying a chitosan solution to the material to obtain treated material; and

[0135] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein: the material comprises textile, preferably fabric, yarn, and / or fibre, preferably wherein: the material is a cotton cellulose material, preferably denim; and / or the colour-agent is natural or synthetic indigo.

[0136] A method of applying antioxidant to a material, and / or imparting antioxidant activity to a material, the method comprising:

[0137] (a) providing a suspension of water-insoluble antioxidant particles in water;

[0138] (b) applying the suspension of water-insoluble particles to the material;

[0139] (c) applying a chitosan solution to the material to obtain treated material; and

[0140] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein the material comprises textile, preferably fabric, yarn, and / or fibre,

[0141] 15029876-2 preferably wherein: the material is a cotton cellulose material, preferably denim; and / or the antioxidant is quercetin and / or resveratrol.

[0142] A method of treating a material with water-insoluble particles, the method comprising:

[0143] (a) providing, preferably preparing, a suspension of water-insoluble particles in water, and preferably sonicating the particles in water;

[0144] (b) applying the suspension of water-insoluble particles to the material;

[0145] (c) applying a solution of chitosan in water to the material to obtain treated material, wherein the solution has a viscosity of greater than 20 cps, preferably greater than 100 cps, more preferably greater than 200 cps, still more preferably greater than 300 cps, still more preferably greater 400 cps; and

[0146] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at room or ambient temperature, wherein the material comprises textile, preferably fabric, yarn, and / or fibre, wherein the step (c) of applying chitosan solution occurs after, preferably immediately after, the step (b) of applying the suspension; or step (b) and step (c) occur simultaneously, and preferably wherein: the particles are water-insoluble colour-agent and / or antioxidant particles; the material is a cotton cellulose material, preferably denim; and / or the suspension does not comprise an additive starch, nanocellulose, nanofibrillated cellulose (NFC), or carboxymethyl cellulose polymer, more preferably wherein the suspension does not comprise an additive polymer.

[0147] A method of treating a material with water-insoluble particles, the method comprising:

[0148] (a) providing a suspension of water-insoluble particles in water;

[0149] (b) applying the suspension of water-insoluble particles to the material;

[0150] (c) applying a solution of chitosan in water to the material to obtain treated material, wherein the solution preferably has a viscosity of greater than 20 cps, more preferably greater than 100 cps, still more preferably greater than 200 cps, still more preferably greater than 300 cps, still more preferably greater 400 cps; and

[0151] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at room or ambient temperature, wherein: the material comprises textile, preferably fabric, yarn, and / or fibre; and

[0152] 15029876-2 the suspension does not comprise an additive starch, nanocellulose, nanofibrillated cellulose (NFC), or carboxymethyl cellulose polymer, more preferably wherein the suspension does not comprise an additive polymer.

[0153] A method of treating a material with water-insoluble particles, the method comprising:

[0154] (a) providing a suspension of water-insoluble particles in water;

[0155] (b) applying the suspension of water-insoluble particles to the material;

[0156] (c) applying a chitosan solution to the material to obtain treated material; and

[0157] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein: the material comprises textile, preferably fabric, yarn, and / or fibre; and the step (c) of applying chitosan solution occurs after, preferably immediately after, the step (b) of applying the suspension; or step (b) and step (c) occur simultaneously.

[0158] A method of treating a material with water-insoluble particles, the method comprising:

[0159] (a) providing a suspension of water-insoluble particles in water;

[0160] (b) applying the suspension of water-insoluble particles to the material;

[0161] (c) applying a chitosan solution to the material to obtain treated material; and

[0162] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein: the material comprises textile, preferably fabric, yarn, and / or fibre; and the particles in the suspension are not nanoparticles.

[0163] A method of treating a material with water-insoluble particles, the method comprising:

[0164] (a) providing a suspension of water-insoluble particles in water;

[0165] (b) applying the suspension of water-insoluble particles to the material;

[0166] (c) applying a chitosan solution to the material to obtain treated material; and

[0167] (d) drying the treated material at a temperature of less than 70 °C, wherein: the material comprises textile, preferably fabric, yarn, and / or fibre.

[0168] A method of treating a material with water-insoluble particles, the method comprising:

[0169] 15029876-2 (a) providing a suspension of water-insoluble particles in water, preferably wherein the suspension is provided at a temperature of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C.;

[0170] (b) applying the suspension of water-insoluble particles to the material;

[0171] (c) applying a chitosan solution to the material to obtain treated material; and

[0172] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein: the material comprises textile, preferably fabric, yarn, and / or fibre; step (b) is conducted at a temperature of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C; and step (c) is conducted at a temperature of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, still more preferably less 60 °C.

[0173] A method of treating a material with water-insoluble particles, the method comprising:

[0174] (a) providing a suspension of water-insoluble particles in water;

[0175] (b) applying the suspension of water-insoluble particles to the material;

[0176] (c) applying a chitosan solution to the material to obtain treated material; and

[0177] (d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein: the material comprises textile, preferably fabric, yarn, and / or fibre; and the method does not comprise a step of drying, curing, heating or baking the material at a temperature of greater than 90 °C, more preferably at a temperature of greater than 80 °C, still more preferably at a temperature of greater than 70 °C, still more preferably at a temperature of greater than 60 °C.

[0178] A method of treating a material with water-insoluble particles, the method comprising:

[0179] (a) providing a suspension of water-insoluble particles in water;

[0180] (b) applying the suspension of water-insoluble particles to the material;

[0181] (c) applying a chitosan solution to the material to obtain treated material; and

[0182] 15029876-2 (d) drying the treated material at a temperature of less than 100 °C, preferably less than 70 °C, wherein: the material comprises textile, preferably fabric, yarn, and / or fibre; and the material is submitted only to temperatures of less than 100 °C, more preferably less than 90 °C, still more preferably less than 80 °C, still more preferably less than 70 °C, preferably wherein the material is kept at room or ambient temperature.

[0183] EXAMPLES

[0184] General Treatment Procedure

[0185] This procedure was used as an overall treatment method, and is followed for subsequent Examples, with variations as specified.

[0186] Strips of scoured cotton fabric (Cotton drill unbleached, Wolfin Materials) of 8 cm length and 3 cm width were cut from a sheet.

[0187] Individual strips of cotton were immersed in a suspension of water-insoluble particles, the nature of the suspension being as specified. Any further additives, if present, are as specified. A stipple brush was used to ensure the particles were evenly dispersed and well penetrated into the fabric. Excess particles were removed with a silicone roller.

[0188] Unless specified otherwise, the fabric strip was immediately immersed in chitosan solution for 30 seconds, then excess chitosan removed using a sponge. The nature of the chitosan solution is as specified.

[0189] In some Examples where specified, the treated fabric was then dried / cured at elevated temperatures. Otherwise, the treated fabric was dried at room temperature.

[0190] General Procedure for Assessing Treatment

[0191] This procedure was used to assess treatment of the material when using particles of colour-agent, and is followed for subsequent Examples, with variations as specified.

[0192] To assess material treatment when using particles of colour-agent, the lightness (L) of the fabric was measured by colorimetry before and after washing. A Color Muse colorimeter was used to determine RGB values and L value, having a 4 mm diameter measurement size. For each strip of fabric a total of 6 readings were taken, 3 on each side of the fabric then calculating an average value.

[0193] 15029876-2 For washing, strips of fabric were stapled to a tea towel so that they were exposed to typical washing movements and friction. The tea towel was washed in a domestic washing machine (Beko, up to 10 kg load) under normal load conditions (by adding 4 additional bath towels), at 40°C, 75 minutes wash time, with a spin cycle of 1400 rpm. A biological detergent pod was used (Aerial). Samples were allowed to dry fully at 22°C prior to taking colorimetry measurements.

[0194] Example 1 Sonication of synthetic indigo

[0195] The purpose of this Example was to prepare an indigo suspension for use in subsequent Examples.

[0196] A suspension of 5% w / v synthetic indigo (12.5 g, 36009 Indigo Synthetic VAT Blue 1 AP Fitzpatrick) was prepared in water (250 mL). This was pumped at 100 mL / min in a recirculation mode through a glass jacketed flow cell containing a 1” diameter ultrasonic probe (P100, Sonic Systems Ltd). The suspension was cooled to 15°C then subjected to sonication at 25W power input. The dye was sampled at 3, 6 and 12 minutes of sonication time, examining under a microscope for change in gross morphology. As shown in Figure 1 , the indigo changed from a grainy appearance to a smooth homogeneous appearance and upon standing did not settle visibly after 12 minutes when placed in a 50 mL glass bottle.

[0197] This Example was repeated using a 10% w / v suspension of indigo, giving an identical result when the suspension was examined under the microscope, as shown in Figure 2.

[0198] Example 2 Sonication of natural indigo

[0199] The purpose of this Example was to prepare an indigo suspension for use in subsequent Examples.

[0200] A suspension of 10% w / v natural indigo (25 g, Ama Herbal Laboratories, Lucknow, India) was prepared in water (250 mL). This was pumped at 100 mL / min in a recirculation mode through a glass jacketed flow cell containing a 1” diameter ultrasonic probe (P100, Sonic Systems Ltd). The suspension was cooled to 15°C then subjected to sonication at 25W power input. The dye was sampled at 6 and 12 minutes of sonication time, examining under a microscope for change in gross morphology.

[0201] As shown in Figure 3, the indigo changed from a grainy appearance to a smooth homogeneous appearance.

[0202] 15029876-2 Example 3: dye performance under different conditions

[0203] The purpose of this Example was to compare dyeing performance under different conditions.

[0204] Example 3a: preparation of particle suspension

[0205] The purpose of this sub-example was to prepare particle suspensions for testing.

[0206] A series of indigo suspensions was prepared containing different polymers, with the compositions shown in Table 1. The polymers were obtained from the following sources:

[0207] Nanofibrillar cellulose- Borregard, Exilva F 01 -L 108663, a 2% suspension;

[0208] Carboxymethyl cellulose- Intra Laboratories;

[0209] Soluble potato starch- Atom Scientific 5273.

[0210] The polymers were dissolved or suspended in water, followed by addition of indigo then homogenized at 20,000 rpm for 1 minute to give a viscous paste (except for where no polymer was added which was not viscous). The final indigo concentration was 5% w / v in each case.

[0211] Table 1

[0212] Example 3b: preparation of chitosan solution

[0213] The purpose of this Example was to prepare a chitosan solution for use in the dyeing process.

[0214] A solution of chitosan (water insoluble from mushroom, 600 cps, Qingdao ChiBio Biotech Co., Ltd, China) was prepared by stirring chitosan (1 g) in water (100 mL) at ambient temperature then adding acetic acid (373 mg) to give a final pH of 5.38. Residual gel particles were dispersed by homogenizing at 20,000 rpm for 2 minutes.

[0215] 15029876-2 Example 3c: dyeing process

[0216] The purpose of this Example was to dye fabric. The general procedure hereinbefore described was followed.

[0217] Strips of scoured cotton fabric (Cotton drill unbleached, Wolfin Textiles) of 8 cm length and 3 cm width were cut from a sheet.

[0218] Individual strips of cotton were immersed in indigo / polymer suspension prepared in Example 3a, using a stipple brush to ensure the dye was evenly dispersed and well penetrated into the fabric. Excess dye was removed with a silicone roller.

[0219] The fabric strip was immediately immersed in chitosan solution prepared in Example 3b for 30 seconds, then excess chitosan removed using a sponge.

[0220] The dyed (chitosan-treated) fabric was then cured at 140°C for 20 minutes.

[0221] Example 3d: process for assessment of dye particle binding

[0222] The purpose of this Example was to assess dye particle binding following

[0223] Example 3c, using the general procedure hereinbefore described.

[0224] The lightness values (L) before and after washing are shown in Table 2 below.

[0225] Table 2

[0226] Surprisingly, it was found that no polymer was needed and gave the best result, with no lightening evident. Nanofibrillar cellulose has conventionally been proposed to be needed for forming a mesh around the particles, but there was no measurable benefit from using this or any of the other polymers, all of which showed a degree of shade lightening.

[0227] Example 3e: effect of curing

[0228] The purpose of this example was to investigate variations to the curing step described in Example 3c.

[0229] 15029876-2 The experiment was repeated, but with the high temperature curing of at 140°C of Example 3c replaced with drying the strips for 1 hour at 22°C. The purpose was to see if the high temperature curing was needed. The results are shown in Table 3 below.

[0230] Table 3

[0231] Surprisingly, it was found that high temperature curing at 140°C was not needed. This offers the possibility of performing the process without energy-intensive heating requirements.

[0232] Example 3f: effect of chitosan treatment

[0233] The purpose of this example was to investigate the omission of the chitosan treatment step described in Example 3c.

[0234] The experiment was repeated, omitting the chitosan treatment of Example 3c and with the high temperature curing at 140°C replaced with drying the strips for 1 hour at 22°C.

[0235] Table 4.

[0236] This shows that the chitosan treatment step is clearly important for achieving good dyeing performance.

[0237] Example 4: varying the drying temperature

[0238] The purpose of this Example was to investigate the effect of drying / curing temperature on dyeing performance.

[0239] The temperature of the drying / curing step was varied. The general treatment procedure hereinbefore described was followed, with 5% w / v synthetic indigo treatment followed by 1% w / v chitosan (600 cps, water insoluble as in Example 3b) treatment with drying / curing at various times and temperatures. The results are shown below in Table 5.

[0240] 15029876-2

[0241] Table 5

[0242] The results show that at all the temperatures tested there was no loss of colour. The colour shade darkened at higher temperature. This offers the possibility of performing the process without energy-intensive heating requirements.

[0243] Example 5: comparing grades of chitosan

[0244] The purpose of this Example was to investigate the effect of different grades of chitosan on dyeing performance.

[0245] Different grades of chitosan (Qingdao ChiBio Biotech Co., Ltd, China) were tested to investigate the influence of molecular weight / viscosity on the dyeing process. Except for 600 cps chitosan (prepared as in Example 3b), the other grades of chitosan were water soluble as their HCI salts. The general treatment procedure hereinbefore described was followed, with 5% w / v synthetic indigo treatment followed by 1 % w / v chitosan treatment with drying at 22°C, with the identity of the chitosan varied. The results are shown below in Table 6.

[0246] Table 6.

[0247] The results show that higher molecular weight / viscosity chitosan offers improved dyeing performance.

[0248] Example 6: comparing indigo concentration

[0249] The purpose of this example to was to investigate the effect of indigo concentration on dyeing performance.

[0250] Different concentrations of indigo dye were tested to see if the process is effective at lower indigo dye concentration. The general treatment procedure hereinbefore described , with 5% w / v synthetic indigo dye and 2.5% w / v synthetic indigo dye treatment followed by 1% w / v chitosan (600 cps, water insoluble as in Example 3b) treatment with drying at 22°C. The results are shown below in Table 7.

[0251] 15029876-2

[0252] Table 7.

[0253] The results show that the process works well at lower indigo dye concentration with acceptable shade lightening. This presents the possibility of performing the process at different indigo dye concentrations.

[0254] Example 7 comparing indigo particle size

[0255] The purpose of this Example was to investigate the impact of indigo particle size on dyeing performance.

[0256] Different particle sizes of indigo were tested to see if the process is more effective with reduced indigo particle size, as shown in Figure 4. Indigo suspensions (5% w / v) from Example 1 (sonicated) and untreated indigo powder were used in the general treatment procedure hereinbefore described, with 1 % w / v chitosan (600 cps, as prepared in Example 3b) treatment with drying at 40°C. The results are shown below in Table 8.

[0257] Table 8.

[0258] The results show that sonicated indigo gave a lower shade lightening than untreated indigo powder. This compares with a AL of 5.5% for homogenized indigo as in Example 6. In addition, it was noted that application of the indigo to the fabric was significantly easier (i.e. faster) using sonicated powdered indigo.

[0259] Example 8: comparing chitosan concentration

[0260] The purpose of this Example was to investigate the effect of chitosan concentration on dyeing performance.

[0261] Different concentrations of chitosan (Qingdao ChiBio Biotech Co., Ltd, China) were tested to investigate the influence of concentration on the dyeing process. 600 cps Chitosan (600 cps, water insoluble) was prepared at 2% w / v as in Example 3b. The general treatment procedure hereinbefore described was used, with 5% w / v synthetic indigo treatment followed by 2% w / v chitosan treatment with drying at 22°C. The results are shown below in Table 9.

[0262] 15029876-2

[0263] Table 9

[0264] The results show that 2% w / v chitosan concentration is as effective as 1%, presenting the possibility of performing the process with different chitosan concentrations. However, when using 1 % w / v chitosan concentration the fabric was found to be desirably less stiff in texture, including after washing.

[0265] Example 9: comparing process sequence

[0266] The purpose of this Example was to investigate the effect on dyeing performance of the ordering of indigo dyeing and chitosan treatment steps.

[0267] The general treatment procedure hereinbefore described, altering the sequence of events: a) indigo dyeing followed by chitosan treatment; b) chitosan treatment followed by indigo dyeing; or c) indigo dyeing and chitosan treatment occurring at the same time.

[0268] For samples 9-1 and 9-2, dyeing was performed with 2.5% w / v sonicated synthetic indigo from Example 1 (5% w / v indigo diluted 1 :1 with water) and 0.5% w / v chitosan as in Example 3b (1% chitosan diluted 1 :1 with water), with the order of steps varied. For Sample 9-3, 5% w / v indigo from Example 1 was mixed with an equal volume of 1% w / v chitosan from Example 3b to give a mixture of indigo (2.5% w / v) and chitosan (0.5% w / v). After dyeing, all samples were dried at 35°C for 30 minutes.

[0269] Table 10.

[0270] Indigo dye followed by chitosan treatment desirably gave the lowest lightening of the three experiments.

[0271] Example 10 - repeated washing

[0272] 15029876-2 The purpose of this Example was to investigate the effect of repeated washing on dyeing performance.

[0273] The general treatment procedure hereinbefore described was performed on 7 strips of cotton fabric with 5% w / v synthetic indigo as prepared in Example 1. The process was performed with 1 % w / v chitosan treatment followed by drying at 22°C. The L value of each of the 7 strips was measured and then the strips stapled to a tea towel. Seven consecutive washes were performed as in the general method hereinbefore described. After each washing cycle a fabric strip was removed and dried for measurement of the L value. The results are shown below in Table 11 .

[0274] Table 11

[0275] The results show that there is desirably no consistent continual loss of dye with sequential washes, for example after 7 washes the L value is the same as before washing commenced.

[0276] Example 11 - natural indigo

[0277] The purpose of this Example was to investigate the use of natural indigo.

[0278] The general treatment procedure hereinbefore described = with 5% w / v natural indigo as prepared in Example 2, by diluting 10% w / v natural indigo suspension with an equal volume of water. The process was done with and without 1% w / v chitosan treatment followed by drying at 40°C. The results are shown below in Table 12.

[0279] Table 12.

[0280] 15029876-2 The results show that natural indigo colour retention is very good with chitosan treatment, but if chitosan treatment is omitted there is considerable lightening of shade.

[0281] Example 12: charcoal

[0282] The purpose of this Example was to investigate the use of charcoal.

[0283] The general treatment procedure hereinbefore described was performed with 5% w / v charcoal (Nature Coatings Inc. USA, NCI-7-C+ black pigment dispersion) treatment with and without 1% w / v chitosan treatment followed by drying at 22°C. The results are shown below in Table 13.

[0284] Table 13

[0285] The results show that charcoal colour retention is very good with chitosan treatment, but if the chitosan treatment is omitted there is lightening of shade.

[0286] Example 13: yellow iron oxide

[0287] The purpose of this Example was to investigate the use of yellow iron oxide.

[0288] The general treatment procedure hereinbefore described, with 5% w / v yellow iron oxide used instead of indigo. To prepare the iron oxide suspension, (1 g, AP Fitzpatrick) was dispersed in 20 mL water, homogenising at 20,000 rpm for 1 minute. Fabric samples were prepared with and without 1% w / v chitosan treatment followed by drying at 40°C. The results are shown below in Table 14.

[0289] Table 14

[0290] The results show that yellow iron oxide colour retention is very good with chitosan treatment, but if the chitosan treatment is omitted there is lightening of shade.

[0291] Example 14: red iron oxide

[0292] 15029876-2 The purpose of this Example was to investigate the use of red iron oxide.

[0293] The general treatment procedure hereinbefore described, with 5% w / v red iron oxide used instead of indigo. To prepare the iron oxide suspension, (1 g, The Crafters Shop) was dispersed in 20 mL water, homogenising for 1 minute. Fabric samples were prepared with and without 1% w / v chitosan treatment followed by drying at 40°C. The results are shown below in Table 15.

[0294] Table 15

[0295] The results show that red iron oxide colour retention is very good with chitosan treatment, but if the chitosan treatment is omitted there is considerable lightening of shade. Examples 12, 13 and 14 thus demonstrate the desirable utility of the method for dye particles beyond indigo.

[0296] Example 15: antioxidants

[0297] The purpose of this Example was to investigate the use of antioxidants

[0298] Example 15a - assay for antioxidant activity

[0299] The ferric reducing antioxidant power (FRAP) assay was used to determine the antioxidant activity of fabric containing bound antioxidant particles. The following solutions were prepared:

[0300] 1. 40 mM HCI. 1 mL 36% HCI (11.6 M) was added to 290 mL water.

[0301] 2. 0.3 M acetate buffer, pH 3.6. 3.1 g sodium acetate trihydrate (Alfa Aesar A16230.36) and 16 mL glacial acetic acid was added to water to make up 1 L.

[0302] 3. 20 mM FeCh. 324 mg FeCh (Alfa Aesar 012357.22) was dissolved in 100 mL water.

[0303] 4. 10 mM 2,4,6-tri-(2-pyridyl)-1 ,3,5-triazine (TPTZ, Alfa Aesar H36052.03) in 40 mM HCI. 50 mg TPTZ was dissolved in 16 mL 40 mM HCI.

[0304] 5. 10 mM FeSC>4(7H2O). 278 mg FeSC>4.(7H2O) (Intralabs) was dissolved in 100 mL water.

[0305] Preparation of Fe2+standard curve and FRAP assay. A series of dilutions of FeSC>4(7H2O) was prepared from 1 mM to 0 mM. A FRAP stock solution was prepared by mixing 25 mL 0.3M acetate buffer, 2.5 mL 20mM FeCh and 2.5 mL 10 mM TPTZ solution.

[0306] 15029876-2 To perform an assay 960 mL of FRAP buffer was mixed with 40 iL of the FeSC FW) solutions and the absorbance at 593 nm measured after incubating at 22°C for 5 minutes, using the FRAP solution as a blank. Figure 5 shows the standard curve obtained.

[0307] To perform a FRAP assay with fabric, 30 mg fabric and 1 mL FRAP reagent were placed in a 2 mL centrifuge tube for and agitated 4 minutes at 22°C. The tube was centrifuged and the absorbance of the supernatant measured at 593 nm, diluting fourfold with water to achieve a reading in the linear range. Results were expressed as mM equivalents of Fe2+from the standard curve.

[0308] Example 15b: quercetin

[0309] Quercetin dihydrate (1 g, Oxford Vitality) was suspended in water (20 mL) and subjected to sonication at 25 W for 3 minutes. The resulting suspension was applied to samples of fabric according to the general treatment procedure hereinbefore described, with and without subsequent 1% w / v chitosan treatment, and with drying at 22°C. Samples of treated cloth were assayed for antioxidant activity as described in Example 15a before and after washing. The results are shown below in Table 16.

[0310] Table 16

[0311] The results showed that with chitosan treatment the antioxidant increased slightly after washing but that severe loss of antioxidant activity occurred in the absence of chitosan treatment.

[0312] Example 15c: resveratrol

[0313] Resveratrol (1 g, Hellenia, Premium Grade Ingredients) was suspended in water (20 mL) and subjected to sonication at 25 Wfor 3 minutes. The resulting suspension was applied to samples of fabric as described in the general treatment procedure hereinbefore described, with and without subsequent 1 % w / v chitosan treatment, and with drying at 22°C. Samples of treated cloth were assayed for antioxidant activity as described in Example 15a before and after washing. The results are shown below in Table 17.

[0314] 15029876-2

[0315] Table 17

[0316] The results showed that with chitosan treatment the antioxidant decreased only slightly after washing, but that severe loss of antioxidant activity occurred in the absence of chitosan treatment.

[0317] Example 15 thus demonstrates that the method can desirably be applied to particles other than dye particles, such as antioxidants.

[0318] Conclusion

[0319] The Examples demonstrate that the method of the present invention leads to effective treatment of textile materials with insoluble particles, including with a variety of dye particles and antioxidant particles. Treatment shows strong resistance to washing, including after repeated washing steps. A step of chitosan treatment has been shown to be particularly important.

[0320] Advantageously, the method has been shown to work with different particle sizes and concentrations. Surprisingly, neither the addition of polymer agents nor the use of high temperature curing steps was found to be required, offering the possibility of a more environmentally-friendly method.

[0321] 15029876-2

Claims

CLAIMS:

1. A method of treating a material with water-insoluble particles, the method comprising:(a) providing a suspension of water-insoluble particles in water;(b) applying the suspension of water-insoluble particles to the material;(c) applying a chitosan solution to the material to obtain treated material; and(d) drying the treated material at a temperature not exceeding 100 °C, preferably at a temperature of less than 70 °C, wherein the material comprises textile, preferably fabric, yarn, and / or fibre.

2. A method according to claim 1 , wherein the material is a cotton cellulose material, preferably denim.

3. A method according to claim 1 or claim 2, wherein the suspension comprises a plurality of different types of water-insoluble particles.

4. A method according to any preceding claim, wherein the particles are waterinsoluble colour-agent and / or antioxidant particles.

5. A method according to any preceding claim, wherein the particles are waterinsoluble colour-agent particles, preferably wherein the colour-agent is natural or synthetic indigo, red or yellow iron oxide, and / or charcoal (e.g. particles of micronised charcoal)6. A method according to any preceding claim, wherein the particles are waterinsoluble antioxidant particles, preferably wherein the antioxidant is quercetin and / or resveratrol.

7. A method according to any preceding claim, wherein the particles have a solubility in water which is less than 100 mg / L, preferably less than 75 mg / L, more preferably less than 50 mg / L, still more preferably less than 35 mg / L.

8. A method according to any preceding claim, wherein step (a) comprises preparing the suspension.15029876-29. A method according to any preceding claim, wherein the method comprises sonicating the particles in water, preferably wherein the sonication is an ultra-sonication.

10. A method according to any preceding claim, wherein the particles in the suspension are micrometre-scale particles, preferably having an average diameter of between 1 to 100 micrometres.

11. A method according to any preceding claim, wherein the suspension comprises between 0.5 to 10 %, preferably 1.5 to 7.5 %, more preferably 2 to 6.5 % w / v of the particles, based on the volume of the suspension.

12. A method according to any preceding claim, wherein the suspension and / or the chitosan solution does not comprise an additive starch, nanocellulose, nanofibrillated cellulose (NFC), or carboxymethyl cellulose polymer, preferably wherein the suspension and / or the chitosan solution does not comprise an additive polymer.

13. A method according to any preceding claim, wherein the chitosan has a viscosity of greater than 20 cps, preferably greater than 100 cps, more preferably greater than 200 cps, still more preferably greater than 300 cps, still more preferably greater 400 cps.

14. A method according to any preceding claim, wherein the chitosan solution comprises 0.25 to 10 %, preferably 0.5 to 5 %, still more preferably 0.75 to 2 %, e.g. about 1 % w / v chitosan, based on the total volume of the solution.

15. A method according to any preceding claim, wherein the chitosan solution is an acidic solution, preferably having a pH of between 4 to 7, more preferably between 5 to 6.

16. A method according to any preceding claim, wherein the chitosan is provided as a water-soluble salt.

17. A method according to any preceding claim, wherein the chitosan is bio-derived chitosan, e.g. plant-derived or animal-derived, preferably crustacean-derived or mushroom-derived.15029876-218. A method according to any preceding claim, wherein the step (c) of applying chitosan solution occurs after, preferably immediately after, the step (b) of applying the suspension.

19. A method according to any preceding claim, wherein step (b) and step (c) occur simultaneously.

20. A method according to any preceding claim, wherein during the step (d) of drying, the material is not submitted to temperatures exceeding 100 °C, preferably not exceeding 50 °C, more preferably not exceeding 35 °C, still more preferably not exceeding 30 °C, still more preferably not exceeding about 25 °C.

21. A method according to any preceding claim, wherein drying is at room temperature or at ambient temperature.

22. A method according to any preceding claim, wherein, after the step (d) of drying the treated material, steps (b) to (d) are repeated.

23. Use of a method according to any preceding claim to impart colour to a material, to colour a material, and / or to dye a material.

24. Use of a method according to any one of claims 1 to 22 to apply antioxidant to a material, and / or to impart antioxidant activity to a material.

25. A material obtained or obtainable, preferably obtained, by a method according to any preceding claim.15029876-2

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