Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P5/00—Other features in dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form
  • D06P5/15—Locally discharging the dyes
  • D06P5/153—Locally discharging the dyes with oxidants

Definitions

• the present invention relates to an environmentally friendly method to improve the treatment for changing the color and tone of a dyed fabric. It is related to a method for increasing the bleaching intensity and improving the reproducibility of ozone bleaching of dyed fabrics by an environmentally friendly aqueous ozone booster, which also ensures time stability of the achievable bleaching effect e.g. during dwelling of the textile before ozone treatment.
• Sandblasting as a very cheap method used in earlier times, was officially banned from production processes due to highly negative impacts on workers' health (silicosis).
• a whole denim textile product is wetted with water and then bleached with ozone.
• the dry ozone treatment process includes spraying water to desired areas of the textile product and bleaching with ozone.
• a drum is loaded with denim textile products together with wetted cotton fabric scraps for cross-wetting, followed by ozone treatment.
• JP2004019084A discloses a method for treating a textile material with ozone after moisturizing it with water.
• a powdery body or granules consisting of water soluble salt are sprinkled over the pre-wetted textile material before ozone treatment.
• Said powder or granules adhere non-uniformly and randomly onto convex parts of the surface, in which discoloration is suppressed at the respective areas by absorption of the surrounding moisture.
• Respective water soluble salts described in this application are sodium sulfate (Na2SO 4 ), calcium chloride (CaC ), magnesium chloride (MgC ), magnesium sulfate (MgS0 4 ) etc., including respective anhydrides or hydrates of said salts.
• Na2SO 4 sodium sulfate
• CaC calcium chloride
• MgC magnesium chloride
• MgS0 4 magnesium sulfate
• alkaline or reducing agents are used to destroy ozone locally, thus preventing discoloration at respective treated areas.
• WO20121 19532A1 There a method for treating denim jeans by topical abrasion, followed by rinsing with water, ozone treatment and final rinsing with water is described, in which no other chemicals are used in any of the steps except water and ozone.
• initial rinsing is necessary to remove the bulk of sizing and to establish moist conditions, which is essential for successful ozone bleaching action as described above.
• a method for changing the color of a dyed material such as, for example, cellulosic fiber, yarn, fabric, or garment in order to obtain a vintage or used look, wherein said dyed material is subjected to a pre- treatment with a hygroscopic substance and thereafter the dyed material is ozone treated.
• the ozone booster is an environmentally friendly and non-hazardous substance or mixture.
• the ozone booster comprises at least one hygroscopic substance.
• the method for increasing the color value change of dyed material comprises the following steps:
• a further embodiment of the invention relates to a method for increasing the color value change of dyed material comprising the following steps:
• the present invention further relates to a garment obtained by the inventive method of applying a hygroscopic substance for increasing the color value change of a dyed material by subsequent ozone treatment.
• Figure 1 Results of ozone bleaching after pretreatment with samples 1 -4 (c.f. Table 1 ) and water as a reference.
• Figure 2 Ozone bleaching after application of different aqueous solutions of hygroscopic substances onto indigo dyed denim textiles.
• Figure 3 Bleaching effect by ozone treatment after application onto indigo, sulfur top and sulfur bottom dyed denim textiles.
• the yarn is treated with high alkalinity during a short period of time.
• This treatment is changing the crystalline structure of the cellulose fibers, swelling and shrinking the fibers, and additionally rounding them off.
• the pretreatment by alkali is responsible for more intense color in the subsequent dyeing step, brighter shades and more ring dyeing as well as superficial dyeing.
• dyeing of cotton yarn for standard blue denim cotton fabrics is carried out with indigo as the main dyestuff.
• the second most important dyestuffs are sulfur dyes, which can be applied solely or in combination with indigo in order to create new effects (so-called bottoming or topping with sulfur dye).
• the bleaching or "used effect” can e.g. be obtained by KMnO 4 , chlorine, organic peroxides, persulfates, reducing agents (e.g. glucose), laser treatment, ozone treatment or even by the action of enzymes (e.g. cellulases, laccases, peroxidases).
• reducing agents e.g. glucose
• enzymes e.g. cellulases, laccases, peroxidases.
• Ozone is already used in the jeans industry. Normally it is used for a final clean-up of the garment before the article of clothing is ready for customers, and to adjust the color of the whole garment. This means that there are many ozone- generators/machines available; however, by virtue of the sole use during the clean-up step and color adjustment, the capacities of these machines are usually not fully exploited. So far it was not possible to carry out reproducible local bleaching on e.g. jeans garments using ozone, since the ozone gas is commonly applied to the whole garment. In contrast, potassium permanganate can be applied to the fabric or garment onto very well-defined areas e.g. by spraying, and is thus preferred in terms of reproducibility and local applicability.
• US20140068871 A1 discloses a method for local jeans bleaching with ozone.
• the garment is moistened locally in order to be efficiently bleached during ozonation.
• Only ozone gas which is dissolved in water in turn acts as an effective bleaching agent.
• any moisture applied locally to the jeans is mostly gone, either by drying or random diffusion into the bulk textile.
• the present invention overcomes this major disadvantage by using an ozone booster for wetting the garment, which comprises at least one chemical of hygroscopic nature.
• the ozone booster may inter alia be applied by spraying directly on the dyed material at desired areas, enabling subsequent local ozone bleaching even after prolonged dwelling.
• the principle of the invention turned out to primarily be based on ensuring a long-lasting and persistent humidity at desired areas of the dyed material, additionally protecting the dyed material against drying due to the special chemical composition of the ozone booster. Only by this it is possible to bleach dyed material reproducibly even after temporary storage.
• the invention can easily be used directly on site with existing equipment and replace environmentally hazardous potassium permanganate spray.
• a completely non-toxic ozone booster is in a first step sprayed or applied otherwise directly on desired and selected areas of the dyed material or on the whole garment; the actual bleaching is subsequently carried out in closed ozonation drums e.g. at room temperature without the need of additional water. This process does not burden the health of the employees and the environment.
• ozone is a very efficient bleaching agent comprising - due to the chemical structure - high selectivity e.g. towards indigo or sulfur dyes.
• direct destruction of the dye by ozone gas is very limited due to decreased reactivity at the solid/gas interface.
• a liquid support is thus enhancing the reactivity and bleaching effect significantly.
• Due to environmental issues in some embodiments an aqueous solution is used as the medium of choice.
• DMSO representing a hygroscopic solvent
• further compounds such as an additional swelling agent, may be used in combination with water for swelling of the cellulose fibers, rendering more reactive sites accessible to bleaching and thus enhancing the bleaching effect even more.
• additional swelling agent may be used in combination with water for swelling of the cellulose fibers, rendering more reactive sites accessible to bleaching and thus enhancing the bleaching effect even more.
• composition of the ozone booster other parameters influencing the bleaching effect are the humidity of the ambient air, the temperature, air pressure, ozone concentration as well as treatment time. High humidity of the ambient air in the factory is prolonging the drying time; the same is true for lower temperatures.
• Ozone is produced directly on-site in closed chambers from ambient air after concentration of oxygen followed by electric discharge, according to the following chemical formula:
• one embodiment of the invention relates to a method for increasing the color value change of a dyed material comprising the following steps:
• One embodiment of the invention relates to a method for increasing the color value change of a dyed material comprising following steps:
• step (b) applying the mixture of step (a) to dyed material
• the fabric or garment is dwelled or pre- dried to a certain extent, preferably at room temperature, but also at elevated temperatures, e.g., up to 120°C.
• the term "textile material” or “fabric” are used interchangeably and each refer to fibers, yarns, fabrics, flexible knitted, woven or non- woven material consisting of a network of natural or artificial fibers (yarn or thread).
• the textile material may also be used in production of further goods such as cloths, garments, carpets, bags, shoes, jewelry, furnishings, artifacts, etc.
• the respective textile material is represented as
• the respective material is a textile material represented by a variety of garments including jeans skirts, jeans jackets, jeans shorts, jeans vests, jeans dresses, and/or corduroy and twill garments.
• the material may be dyed or coated with a dye, in which the dye may be selected from natural or synthetic dyes of every class; the industry currently preferably uses indigo dye, sulfur dyes and other dyestuff classes (e.g. dischargeable dyes etc.), or combinations thereof as top and bottom blends or mixtures.
• a dye in which the dye may be selected from natural or synthetic dyes of every class; the industry currently preferably uses indigo dye, sulfur dyes and other dyestuff classes (e.g. dischargeable dyes etc.), or combinations thereof as top and bottom blends or mixtures.
• the textile material may be of cellulosic origin and selected from natural fibers, such as bast fibers like jute, flax, hemp, leaf fibers such as sisal, seed fibers such as cotton, or bamboo fibers, or man-made fibers such as lyocell fibers, viscose, rayon type fibers, modal, cupro and/or acetate type cellulosic fibers and optionally mixtures with synthetic fibers, if applicable and chemically compatible.
• natural fibers such as bast fibers like jute, flax, hemp, leaf fibers such as sisal, seed fibers such as cotton, or bamboo fibers
• man-made fibers such as lyocell fibers, viscose, rayon type fibers, modal, cupro and/or acetate type cellulosic fibers and optionally mixtures with synthetic fibers, if applicable and chemically compatible.
• the fabric or garment is dwelled for at least 5 minutes or up to 24 hours, or even longer if necessary.
• ozone booster refers to an environmentally friendly and non-hazardous compound or mixture.
• Hazardous compounds such as for example listed in the ECHA database of substances of very high concern, are thus avoided.
• Suitable non-hazardous compounds are e.g. hygroscopic substances.
• the hygroscopic substance may be, but not limited to, selected from the group of hygroscopic inorganic salts, organic compounds, liquids and solvents, alcohols, dicarboxylic and carboxylic acids and deliquescent compounds as well as respective an hydrates or hyd rated forms, or mixtures thereof.
• the hygroscopic compound may be selected from the group, but not limited to, D SO, aluminum chloride, aluminum nitrate, calcium chloride, calcium nitrate, calcium bromide, carnallite, lithium chloride, lithium bromide, lithium iodide, lithium nitrate, lithium sulfate, magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium bromide, manganese sulfate, tin sulfate, dicarboxylic acids such as malonic acid or oxalic acid, glutaric acid, urea, alpha hydroxy acids such as lactic acid, polyols as for example sorbitol, xylitol, maltitol, glycerol, sodium bromide, sodium sulfate, sodium bisulfate, sodium chloride, sodium nitrate, tachyhydrite, zinc chloride, zinc nitrate, potassium chloride, potassium nitrate, potassium sulf
• the concentration of the hygroscopic substance in aqueous solution is typically in the range of 0.1 -90 w-%, preferably in the range of 10-80%, more
• the hygroscopic substance is solely limited by its respective solubility in water, in which also saturated solutions may be applied, but more preferably the concentration is at least 5-10% below the limit of solubility due to reasons of stability of the solution and the avoidance of unwanted precipitation.
• textile auxiliary chemicals may be added to the at least one hygroscopic substance in any combination and concentration in solid or liquid form to improve the usability and performance of the said mixture comprising at least one hygroscopic substance and water according to what is required: e.g. dispersants, wetting agents, surfactants, thickening agents, colorants, tinting agents, silicones, leveling agents, antifoams, antimigration agents, antibackstaining agents, softeners, stabilizers, buffer substances, substances for pH adjustment, and optical brightening agents.
• dispersants e.g. dispersants, wetting agents, surfactants, thickening agents, colorants, tinting agents, silicones, leveling agents, antifoams, antimigration agents, antibackstaining agents, softeners, stabilizers, buffer substances, substances for pH adjustment, and optical brightening agents.
• Further chemicals may be added to impart more desirable improvement of the textile in hand feel or other property like softness, waterproofing, antimicrobial or microbe-reducing chemicals, encapsulated perfumes, etc., or co-solvents (alcohols, ketones, protic solvents, aprotic solvents, polar solvents, apolar solvents, nonionic solvents, ionic solvents, ionic liquids, emulsifying and dispersing agents etc.).
• co-solvents alcohols, ketones, protic solvents, aprotic solvents, polar solvents, apolar solvents, nonionic solvents, ionic solvents, ionic liquids, emulsifying and dispersing agents etc.
• Respective thickening agents may be selected from, but not limited to, compounds which are commonly used as textile auxiliaries, food additives, in cosmetics and personal hygiene products, i.e. starch and modified starches, cellulose and modified celluloses (i.e. methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropylmethyl cellulose, hydroxypropyl cellulose, ethylhydroxyethyl cellulose), alginates (i.e.
• the thickening agent or mixtures thereof may increase the viscosity of the aqueous solution up to 10,000 cP, more preferably up to 1 ,000 cP, most preferably 100-200 cP, or similar to water.
• the solution is preferably an aqueous solution, but it may be also applied separately and stepwise or as at least one pure hygroscopic substance or mixture in powdered or any solid form.
• the textile material may also be evenly or unevenly impregnated with said composition using any of the conventional techniques.
• at least one marker dye is added to the aqueous mixture.
• the marker dye is selected from, for example, but not limited to, acid dyes, azoic dyes like methylene red, basic dyes, dispersing dyes, vat dyes, sulfur dyes and others or food dyes such as for example 8'-Apo- -caroten-8'-al, Allura Red AC, Aluminum, Amaranth, Annatto (Norbixin), Anthocyane, Azorubin, Betanin, Brillant black, Brillant blue, Brown FK, Brown HT, Canthaxanthin, Capsanthin, Carmoisine, Carotin, Chinolin yellow, Chlorophyll, chromene (e.g.
• the marker dye is preferably a food dye.
• the aqueous mixture may further comprise a colorant.
• the colorant is selected from the same group of dyes as indicated above.
• the colorant may be added in order to increase the visibility of the aqueous mixture during spraying.
• the colorant may be added in a concentration in the range of 0.0001 to 10%, preferably in the range of 0.01 to 5%, most preferably in the range of 0.01 to 2%.
• the aqueous mixture may further comprise a wetting agent or surfactant.
• the wetting agent/surfactant is added for increasing the penetration activity of the aqueous solution.
• the wetting agent is for example a nonionic or ionic surfactant, most preferably a nonionic surfactant.
• the wetting agent is a mixture of polyglycol ethers of fatty acid alcohols, thus an alcohol alkoxylate.
• the wetting agent may be added in a concentration in the range of 0.001 to 10%, but more preferably in the range of 0.01 to 5%, most preferably 0.01 -1 %.
• the aqueous mixture may further comprise a softening agent.
• the softening agent is for example an anionic/cationic but also a zwitterionic/non-ionic, sometimes silicone-based, surface active compound.
• the softening agent may be added in a concentration in the range of 0.1 to 25%, or more preferably in the range of 0.1 to 10%.
• the aqueous solution comprises up to 10- 95 w-% DMSO.
• the hygroscopic substance containing aqueous solution is applied onto a desized dyed textile.
• the treated textile is subjected to ozone treatment after application of the aqueous solution containing at least one hygroscopic substance.
• Ozone treatment means contacting the said treated textile with ozone gas in batch or continuous systems. This can for example be done in a washing machine, which is dedicated to ozone washing and thus connected to an ozone generator.
• the ozonation is typically carried out at room temperature during tumbling of the textile without the use of additional water. New machine types are being recently used or are under development which e.g. apply ozone gas in continuous processes, are suitable as well.
• the ozonation time is depending on the ozone concentration and ozone production capacity of the respective ozone generator as well as the desired bleaching effect. The lower the ozone concentration, the longer the reaction time for achieving a desired effect is.
• a drum is loaded with denim textile products together with pre-wetted cotton fabric scraps (previously soaked in an aqueous solution comprising at least one hygroscopic substance) for cross-wetting, followed by ozone treatment. This way it is possible to achieve random bleaching enhancement at cross-wetted areas.
• a fabric is soaked into a solution containing at least one hygroscopic substance.
• the fabric is then dried and optionally a cover layer comprising a polymer coating and/or sizing agent is applied e.g. by spraying, dipping etc. Sizing or coating agents are well-known to a person skilled in the art.
• the fabric is then dried again. After mechanical abrasion (handsanding) and/or laser treatment the textile is allowed to dwell followed by subsequent ozonized. A contrast will be achieved by the above treatment even if no hygroscopic substance is used. However, the presence of the hygroscopic substance will significantly increase the contrast between the abraded and non-abraded parts of the fabric.
• the intensity of the contrast between the abraded and non-abraded parts of the fabric is apparent when compared to non-treated fabric.
• the hygroscopic salt is added to a sizing bath or coating of a yarn. The yarn is then converted into a fabric by e.g.
• the textile After removing the surface coating by means of mechanical abrasion (handsanding) and/or laser treatment etc., the textile is allowed to dwell and subsequently ozonized.
• the hygroscopic salt is applied below the size layer of a yarn or textile.
• the key dependent variable in replicating the worn out look is the abrasion intensity, brightness or whiteness of the image.
• Intensity refers to the purity of a hue. Intensity is also known as chroma or saturation.
• the highest intensity refers to the purity of a hue.
• the highest intensity or purity of a hue is the hue as it appears in the spectrum or on the color wheel. A hue reduced in intensity is called a tone.
• Color also has a value, i.e. a relative degree of lightness or darkness. Most colors are recognizable in a full range of values; e.g. we identify as a form of "red" everything from the palest pink to the darkest maroon. Even though we assign different names to the different values of red we still know that they are derived from red. All hues have a normal value; the lightness or darkness of that hue as it appears in the spectrum. Yellow, for example, is a light-valued color while violet is a dark-valued color. As a result, there will be an uneven range of light or dark values for each hue.
• the color can be measured by means of spectrophotometers and tristimulus colorimeters (Chroma Meters). They measure reflected and transmitted color of objects. These are used in industrial fields and other areas for color quality control, grading by color, and CCM applications on a wide variety of subjects, including automotive parts, paint, plastic, textiles, construction materials and foods, and correcting vision problems.
• the space itself is a three-dimensional real number space that contains an infinite number of possible representations of colors.
• the space is usually mapped onto a three-dimensional integer space for device-independent digital representation, and for these reasons, the L * , a * , and b * values are usually absolute, with a pre-defined range.
• the red/green opponent colors are represented along the a * axis, with green at negative a * values and red at positive a * values.
• the yellow/blue opponent colors are represented along the b * axis, with blue at negative b * values and yellow at positive b * values.
• a denim garment is treated with an aqueous solution containing at least one hygroscopic substance and subsequently subjected to ozonation.
• a denim garment is treated with sandpaper to roughen parts of the surface and then treated with an aqueous solution containing at least one hygroscopic substance and subsequently subjected to ozonation.
• a denim garment is treated locally with an aqueous solution containing at least one hygroscopic substance, allowed to dwell under ambient or elevated temperature conditions for several hours and subsequently subjected to ozonation.
• a denim garment is optionally pretreated with desizing agents, enzymes, chlorine, glucose, peroxides, etc., and dried, then treated locally with an aqueous solution containing at least one hygroscopic substance, allowed to dry under ambient or elevated temperature conditions for several hours and subsequently subjected to ozonation.
• a whole denim garment is treated with an aqueous solution containing at least one hygroscopic substance by immersion, then centrifuged and subsequently subjected to ozonation.
• a dyed fabric is treated with an aqueous solution containing at least one hygroscopic substance and subsequently subjected to ozonation.
• a dyed yarn is treated with an aqueous solution containing at least one hygroscopic substance by immersion, then coated, dried and processed into a garment and subsequently subjected to ozonation.
• a colored yarn is treated with an aqueous solution containing at least one hygroscopic substance by immersion, then sized, dried and processed into a garment, in which the size is removed by any means of scraping, lasering, etc. and
• a whole denim garment is treated with an aqueous solution containing at least one hygroscopic substance, allowed to dry under ambient or elevated
• a material is treated with an aqueous solution containing at least one hygroscopic substance, allowed to dry and then dyed and then subjected to ozonation.
• the said aqueous solution comprising at least one hygroscopic salt is applied either by brushing, foaming, immersion, padding, printing, sponging, nebulizing, spraying, or by other methods such as stone and/or powder carrier (contact method).
• the treated garment is ozonized directly or after drying/dwelling or storage for several hours - like during common production conditions in the industry, respectively.
• auxiliary chemicals are added to and dissolved in the liquid ozone booster in any combination and concentration: this applies to antibackstaining agents, antifoaming agents, antimigration agents, colorants, dispersants, leveling agents, optical brighteners, silicones, softeners, stabilizers, surfactants, thickening agents, tinting agents and wetting agents.
• the said treated garment is ozonized directly or after drying/dwelling or storage for several hours, respectively.
• a raw denim garment was abraded by laser or hand sanding to mark specific used look areas. Subsequently said inventive aqueous solution containing at least one hygroscopic substance was sprayed or applied by brush or sponge on the abraded areas and then subjected to ozone treatment.
• a raw denim garment was desized and dried. Subsequently an aqueous solution containing at least one hygroscopic substance was sprayed or applied by brush or sponge on the abraded areas. [00101 ] A raw denim garment is used as it is, or desized, and/or stonewashed or enzyme washed and/or bleached if desired and dried. Subsequently an aqueous solution containing at least one hygroscopic substance is sprayed or applied by brush or sponge or towel on specific areas of the garment.
• Table 1 depicts compositions of aqueous solutions which were applied to denim garments.
• a raw denim fabric is used as it is, or desized, and/or stonewashed or enzyme washed and/or bleached if desired and dried. Subsequently said aqueous solution containing at least one hygroscopic substance is sprayed or applied by brush or sponge or towel on specific areas of the garment. The treated fabric is then ozonized directly or after drying or storage for several hours, respectively, in
• humectants were tested as shown in Table 1 .
• Water plus thickener was used as a control and reference experiment. AL values were measured against the untreated part of the fabric in the middle of each sample (c.f. Fig. 1 ).
• Fig. 1 The effect of boosting the ozone bleaching intensity is shown in Fig. 1 for samples 1 -4 including the control sample (pure water + thickener). Samples were treated with ozone for 6 min at room temperature; one half of the sample area was sprayed with the respective solutions as shown in Table 1 and allowed to dwell/hang for two hours at ambient conditions. The other half was freshly sprayed before ozonation in order to compare the bleaching effect to the respective aged sample.
• the garment is then allowed to stand/dwell under ambient conditions for several hours simulating industrial process streams and waiting periods.
• the garment is then subjected to ozonation in a closed drum for a certain period of time (typically several minutes up to hours), in which the actual bleaching by ozone is taking place. Due to the wetting properties of the applied solution only pre-treated areas get locally bleached efficiently, whereas non-treated and thus dry regions undergo traditional "cleaning-up", in which comparably intense bleaching is not possible.
• Fig. 1 the results of ozone bleaching after pretreatment with samples 1 -4 and thickened water as a reference are depicted.

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