Indigo-free fabric with jean visual appearance

Abstract

The present invention relates to an indigo-free fabric having the visual appearance of denim and to a method for producing said fabric.

Description

Technical Field

[0001] The present invention relates to the technical field of denim fabrics and garments and methods for manufacturing such denim fabrics and garments. Background Art

[0002] Denim is a strong and durable fabric with a twill weave, where each warp yarn is interlaced with multiple weft yarns (usually 2 - 4). The unique appearance of denim fabric is mainly attributed to denim weaving. Usually only the warp yarns are dyed, for example, indigo dyed, while the weft yarns remain white. Denim is different from other fabrics because it has diagonal ribs on one side.

[0003] Industrial methods for manufacturing denim fabrics include yarn production, yarn dyeing, weaving, and finishing. Indigo, indigo derivatives, and sulfur dyes are the main colorants used for dyeing the yarns used in the denim manufacturing process. Although it is a fact that indigo, its derivatives, and sulfur dyes are vat dyes, they have poor affinity for cellulose fibers when in their reduced and solubilized form, which is different from other vat dyes. Because of the poor dye absorbency, a multi-padding and dyeing procedure with intermediate drying is usually required to achieve a gradual shade build-up. For example, to obtain a deep shade, it is necessary to immerse up to eight times in a leuco indigo bath, making the manufacturing process lengthy. Additionally, the dyeing method produces a large volume of wastewater. For example, dyeing one denim garment consumes about 50 - 100L of water loaded with toxic reducing agents and alkalis, and the toxic reducing agents and alkalis remain in the wastewater as effluents. Moreover, the currently used indigo dyeing method can produce single-tone yarns and fabrics, which need to be stored before further processing, thus increasing production costs. Another disadvantage of the currently used manufacturing method is the back-staining of denim fabrics and / or garments during the finishing step, especially during stone washing and / or enzyme washing. Back-staining means that the detached indigo or leuco indigo soils the weft yarns and / or pocket linings, and results in a decrease in the contrast between the white weft yarns and the blue warp yarns.

[0004] Therefore, there is a need for a method for manufacturing fabrics and garments with a denim visual appearance that alleviates the above disadvantages. Specifically, there is a need for a cost-effective and advantageous method for manufacturing fabrics with a denim visual appearance and their garments that is environmentally friendly, especially in terms of water and energy consumption, and can advantageously produce multiple fabrics with a denim visual appearance. Summary of the Invention

[0005] Therefore, an object of the present invention is to provide an indigo-free method for manufacturing a fabric with a denim visual appearance, which comprises the following steps:

[0006] a) providing an uncolored fabric containing at least 70 wt% of cellulose fibers;

[0007] b) Contact the uncolored fabric with an alkaline solution;

[0008] c) Inkjet print a parallel straight line pattern on the back side of the fabric or in a certain area of the back side of the fabric with one or more inks to provide the visual appearance of the back side of denim,

[0009] wherein

[0010] each of the one or more inks contains a reactive dye and preferably has a viscosity of 5 cP - 9 cP at a shear rate of 25 °C and 200 - 400 s, -1 more preferably 6 cP - 7 cP;

[0011] d) Dry the fabric;

[0012] e) Inkjet print on the front side of the fabric or in a certain area of the front side of the fabric with one or more inks to provide the visual appearance of the front side of denim,

[0013] wherein

[0014] each of the one or more inks contains a reactive dye and preferably has a viscosity of 5 cP - 9 cP at a shear rate of 25 °C and 200 - 400 s, -1 more preferably 6 cP - 7 cP;

[0015] f) Fix the reactive dye to the fabric; and

[0016] g) Optionally wash and dry the fabric.

[0017] This document also claims and describes a method for manufacturing an indigo - free garment, preferably denim, having the visual appearance of denim, which includes the step of transforming the fabric claimed and described herein into a garment.

[0018] According to another aspect of the present invention, there is provided an indigo - free fabric having the visual appearance of denim. The indigo - free fabric contains at least 70 wt% of cellulose fibers. The cellulose fibers contain hydroxyl groups substituted by a structural moiety of the general formula Chr - L -, where Chr is a chromogen and - L - is a linking group that links the chromogen to the oxygen of the hydroxyl group. The back side of the fabric or a certain area of the back side has an inkjet - printed parallel straight line pattern and the visual appearance of the back side of denim. The front side of the fabric or a certain area of the front side has an inkjet - printed pattern having the visual appearance of the front side of denim.

[0019] According to another aspect of the present invention, there is provided an indigo - free garment, preferably denim, which is made of the indigo - free denim fabric claimed and described herein or obtained by the manufacturing method claimed and described herein. Description of the Drawings

[0020] Figure 1 shows a woven fabric according to the present invention and a sample of a denim garment according to the present invention. The fabric and the garment are manufactured by the method claimed herein. The fabric and the garment have the visual appearance and texture of black denim.

[0021] A) The back side of the fabric with a printed pattern of parallel straight lines. The lines are printed at an angle of 110° with respect to the rib, and the width is 0.3 mm. The distance between every two adjacent lines is 0.7 mm;

[0022] B) The front side of the fabric with a printed pattern;

[0023] C) A sample of a denim garment made from the fabric.

[0024] Figure 2 shows a woven fabric according to the present invention and a sample of a garment according to the present invention. The fabric and the garment are manufactured by the method claimed herein. The fabric and the garment have the visual appearance and texture of blue denim.

[0025] A) The back side of the fabric with a printed pattern of parallel straight lines. The lines are printed at an angle of 110° with respect to the rib, and the width is 0.2 mm. The distance between every two adjacent lines is 0.6 mm;

[0026] B) The front side of the fabric with a printed pattern;

[0027] C) A sample of a denim garment made from the fabric. Detailed Description of the Invention

[0028] Accordingly, an object of the present invention is to address the need for a method for cost - effectively manufacturing a fabric and its garment, which fabric and garment have the visual appearance of denim, excellent color fastness properties, and no risk of reverse dyeing during washing, which is environmentally friendly, and which is capable of advantageously producing multiple fabrics having the visual appearance of denim. This object is achieved by the manufacturing method according to claims 1 and 10, the fabric according to claims 11 and 14, and the garment according to claim 15. Preferred embodiments are disclosed in the description and the dependent claims.

[0029] The present invention will be described in more detail below.

[0030] When the present specification refers to "preferred" embodiments / features, it is considered that combinations of these "preferred" embodiments / features are also disclosed, provided that the specific combinations of "preferred" embodiments / features are technically meaningful.

[0031] Unless otherwise indicated, the following definitions shall apply to the present specification:

[0032] As used herein, the terms "a", "an", "the" and similar terms used in the context of the present invention (especially in the context of the claims) are to be construed as covering both the singular and the plural, unless otherwise indicated herein or clearly contradictory in context.

[0033] As used herein, the term "and / or" means that members of the group can all be present or only one can be present. For example, "A and / or B" means "only A, or only B, or both A and B". In the case of "only A", the term also includes the possibility of the absence of B, i.e., "only A, not B".

[0034] As used herein, the terms "comprising", "including" and "containing" are used herein in their open-ended, non-limiting sense. It should be understood that different embodiments, preferences and ranges can be combined as needed. Thus, for example, a solution containing compound A can contain other compounds in addition to A. However, as a specific embodiment thereof, the term "comprising" also covers the more restrictive meanings of "consisting essentially of" and "consisting of". Thus, for example, "a solution containing A, B and optionally C" can also (essentially) consist of A and B, or (essentially) consist of A, B and C. As used herein, the transitional phrase "consisting essentially of" (and its grammatical variants) is construed to include the recited materials or steps and those that do not materially affect the basic and novel characteristics of the claimed invention. Thus, the term "consisting essentially of" should not be construed as equivalent to "comprising".

[0035] As used herein, the term "about" means that the quantity or value being discussed can be the specific value claimed or some other value adjacent thereto. Generally, the term "about" indicating a value is intended to mean within the range of ±5% of that value. As an example, the expression "about 100" means a range of 100 ± 5, i.e., a range of 95 - 105. Preferably, the range indicated by the term "about" means within ±3% of that value, more preferably ±1%. Generally, when the term "about" is used, it can be expected that similar results or effects according to the present invention can be obtained within the range of ±5% of the indicated value.

[0036] Surprisingly, it has been found that a method comprising the following steps provides an indigo-free fabric having a realistic denim visual appearance, as shown in FIGS. 1 and 2:

[0037] a) providing an uncolored fabric containing at least 70 wt% of cellulose fibers;

[0038] b) contacting the uncolored fabric with an alkali solution;

[0039] c) Inkjet print, preferably piezo inkjet print, parallel straight line patterns on the back side of the fabric or in a certain area of the back side of the fabric with one or more inks to provide the visual appearance of the back side of the denim,

[0040] wherein

[0041] each of the one or more inks contains a reactive dye and preferably has a viscosity of 5 cP - 9 cP, more preferably 6 cP - 7 cP at a shear rate of 200 - 400 s-1 at 25 °C; -1

[0042] d) Dry the fabric;

[0043] e) Inkjet print, preferably piezo inkjet print, on the front side of the fabric or in a certain area of the front side of the fabric with one or more inks to provide the visual appearance of the front side of the denim, wherein

[0044] each of the one or more inks contains a reactive dye and preferably has a viscosity of 5 cP - 9 cP, more preferably 6 cP - 7 cP at a shear rate of 200 - 400 s-1 at 25 °C; -1

[0045] f) Fix the reactive dye onto the fabric; and

[0046] g) Optionally wash and dry the fabric. Due to the color gamut, high quality and printing speed (up to 600 m / h) of the inkjet printing technology, the manufacturing method claimed herein can produce a variety of fabrics in a reproducible, cost-effective and advantageous manner, including small-batch fabrics with the visual appearance of denim. The use of reactive dyes prevents the backstaining phenomenon encountered in manufacturing methods using indigo as a colorant. Advantageously, the manufacturing method claimed and described herein does not produce a large amount of wastewater as in the manufacturing method using indigo as a colorant and is environmentally friendly, especially in terms of energy and water consumption. 2

[0047] Preferably, the width of the parallel straight lines printed in step c) is 0.1 mm - 2 mm, and the distance between every two adjacent lines is 0.1 mm - 5 mm. More preferably, the width of the straight lines is 0.1 mm - 1 mm, and / or the distance between two adjacent lines is 0.1 mm - 1 mm.

[0048] As used herein, the term "indigo-free method" refers to a method in which the fabric is dyed without using indigo or indigo derivatives.

[0049] ​​​The term "indigo derivative" refers to an indigo molecule substituted with one or more substituents. The substitution can be carried out at any available position in the indole structural moiety. Examples of substituents include, but are not limited to, alkyl, alkoxy, aryl, aryloxy, acyl, fluoro, chloro, bromo, and iodo groups.

[0050] The term "undyed fabric" refers to a fabric made of fibers that have not been previously contacted with a colorant. The undyed fabric described herein can be any woven or knitted fabric containing at least 70 wt% of cellulose fibers.

[0051] Preferably, the undyed fabric is a cotton fabric, a lyocell fabric, a linen fabric, a viscose fabric, a hemp fabric, or a regenerated cellulose fabric, more preferably a cotton fabric, optionally containing elastomeric fibers and / or polyester (PES) fibers. Examples of cotton fabrics include, but are not limited to, 100% cotton, 70% / 30% cotton and PES blends, and 94 - 97% / 6 - 3% cotton and elastomeric fiber blends.

[0052] As used herein, a certain area on the back side / front side of the fabric accounts for at least 70%, preferably at least 80%, of the total area of the back side / front side of the fabric. The remaining non - printed areas on the back side and / or front side of the fabric can be used to personalize the fabric and its garments, such as adding photos, patterns, or logos.

[0053] To obtain a fabric with the visual appearance and texture of denim, the undyed fabric is preferably a knitted fabric with a diagonal rib, such as a fabric with such a twill weave, where each warp thread interlaces with a plurality of weft threads, and parallel straight lines are printed at an angle of 60° - 120° relative to the rib. Thus, a preferred manufacturing method according to the present invention includes the following steps:

[0054] a) Providing an undyed fabric containing at least 70 wt% of cellulose fibers, wherein the fabric is a knitted fabric with a diagonal rib;

[0055] b) Contacting the fabric with an alkali solution;

[0056] c) Ink - jet printing a parallel straight - line pattern on the back side of the fabric or in a certain area of the back side of the fabric with one or more inks to provide the visual appearance of the back side of denim,

[0057] wherein

[0058] each of the one or more inks contains a reactive dye and preferably has a viscosity of 5 cP - 9 cP at a shear rate of 25 °C and 200 - 400 s, -1 more preferably 6 cP - 7 cP,

[0059] The lines are printed at an angle of 60° - 120° relative to the ribbing, and

[0060] preferably the width of the lines is 0.1 mm - 2 mm, and the distance between every two adjacent lines is 0.1 mm - 5 mm;

[0061] d) Dry the fabric;

[0062] e) Inkjet print the front side of the fabric or a certain area of the front side of the fabric with one or more inks to provide the visual appearance of the front side of denim, wherein

[0063] each of the one or more inks contains a reactive dye, and preferably at 25 °C and 200 - 400 s -1 the viscosity at a shear rate is 5 cP - 9 cP, more preferably 6 cP - 7 cP;

[0064] f) Fix the reactive dye to the fabric; and

[0065] g) Optionally wash and dry the fabric.

[0066] In the method claimed and described herein, step c) is carried out before step e), i.e., the back side of the fabric is printed before the front side of the fabric. This order of steps c), d) and e) reduces the risk of color contamination from the front side and ensures high quality of the parallel straight line pattern printed on the back side of the fabric.

[0067] Using inkjet printing technology in the manufacturing method claimed and described herein enables the production of such a fabric having different hues and / or colors on the front side and the back side of the fabric. In a preferred method according to the present invention, the obtained fabric has at least two different hues on the front side. In another preferred method according to the present invention, the obtained fabric has a first hue on the front side and a second hue on the back side, the first hue being different from the second hue.

[0068] The one or more inks used for inkjet printing in steps c) and e) of the manufacturing method claimed and described herein contain reactive dyes. As is well known to those skilled in the art, reactive dyes contain a chromogen or chromophore moiety, and one or more reactive functionalities which are connected to the chromogen via a bridging unit. The chromogen or chromophore moiety provides the color for the dye. The one or more reactive functionalities react with the cellulose fibers contained in the fabric by a nucleophilic substitution or nucleophilic addition mechanism to form covalent bonds. Due to the strong covalent bonds between the dye and the cellulose fibers, reactive dyes provide significant fastness properties. Examples of suitable reactive dyes include, but are not limited to C Yellow C - 5G (Supplier: Huntsman), C Orange C-G (Supplier: Huntsman), C Red C-2G (Supplier: Huntsman), C Red C-R (Supplier: Huntsman), C Blue C-4R (Supplier: Huntsman), C Turqouise C-GN (Supplier: Huntsman), C Black C-N (Supplier: Huntsman), EVERPLUS Yellow L-6G (Supplier: EVERLIGHT), EVERPLUS Orange L-2R (Supplier: EVERLIGHT), EVERPLUS CYAN L-G (Supplier: EVERLIGHT), EVERPLUS Blue L-3R (Supplier: EVERLIGHT; CAS No.: 61968-93-2), EVERPLUS Red L-6B (Supplier: EVERLIGHT; CAS No.: 113653-03-5) and EVERPLUS Black SGR (Supplier: EVERLIGHT; CAS No.: 17095-24-8).

[0069] Preferably, one or more inks used in steps c) and / or e) of the manufacturing method claimed and described herein have a viscosity of 5 cP - 9 cP at a shear rate of 25 °C and 200 - 400 s -1 and more preferably 6 cP - 7 cP, and / or contain

[0070] - 10 - 25 wt% of a reactive dye;

[0071] - 25 - 28 wt% of a wetting agent;

[0072] - 0.25 - 1 wt% of a biocide;

[0073] - 0.02 - 0.5 wt% of a surfactant;

[0074] - 0.5 - 2 wt% of a complexing agent;

[0075] - 2 - 15 wt% of a solubilizer;

[0076] - 0.25 - 1% of an acid;

[0077] - up to 2 wt% of a thickening agent; and

[0078] - the balance being water.

[0079] The ink may contain 15 wt% of C Yellow C-5G, or 17 wt% of C Orange C-G, or 18 wt% of C Red C-2G, or 20 wt% of C Red C-R, or 21 wt% of C Blue C-4R, or 18 wt% of C Turquoise C-GN, or 23 wt% of C Black C-N.

[0080] Examples of wetting agents include but are not limited to propylene glycol (IUPAC name: propane-1,2-diol). Examples of biocides include but are not limited to Proxel GXL (IUPAC name: benzisothiazolinone; supplier: Azelis Switzerland). Examples of surfactants include but are not limited to Zonyl FSO (fluorosurfactant, commercially available from Sigma-Aldrich). Examples of complexing agents include but are not limited to M (supplier: BASF). Examples of solubilizers include but are not limited to caprolactam (IUPAC name: azepan-2-one). Examples of acids include but are not limited to citric acid. Examples of thickeners include but are not limited to polyethylene glycol P41 (commercially available from Omya).

[0081] Without being limited to theory, it can be considered that in the manufacturing methods claimed and described herein, the CMYK set of co-blendable inks (i.e., cyan (C) ink, magenta (M) ink, yellow (Y) ink, and black (K) ink) is sufficient to achieve the entire color space of denim. To be able to expand the color space, additional inks such as orange, blue, green, and gray inks can be used in step c) and / or e). An example of a suitable ink for the method of the present invention is an ink having the following composition:

[0082]

[0083] Another ink suitable for the manufacturing method of the present invention is the SwissJet NR7HD ink commercially available from SPC Switzerland (e.g.: SwissJet NR7 HD Yellow, SwissJet NR7HD Magenta, SwissJet NR7 HD Cyan, SwissJet NR7 HD Black).

[0084] In a preferred embodiment, the reactive dyes present in one or more inks used in step c) and one or more inks used in step e) are mono-reactive dyes containing one reactive functionality. The reactive functionality is preferably selected from mono-chlorotriazine reactive functionality, mono-fluorotriazine reactive functionality, and mono-vinylsulfone reactive functionality, more preferably selected from mono-chlorotriazine reactive functionality and mono-vinylsulfone reactive functionality. Examples of suitable mono-reactive dyes include, but are not limited to, EVERPLUS Yellow L-6G (supplier: EVERLIGHT), EVERPLUS Orange L-2R (supplier: EVERLIGHT), EVERPLUS CYAN L-G (supplier: EVERLIGHT), EVERPLUS Blue L-3R (supplier: EVERLIGHT; CAS number: 61968-93-2), EVERPLUS Red L-6B (supplier: EVERLIGHT; CAS number: 113653-03-5), and EVERPLUS Black SGR (supplier: EVERLIGHT; CAS number: 17095-24-8). In this embodiment, step b) preferably includes:

[0085] b-1) padding the uncolored fabric with an aqueous alkali solution containing the following components:

[0086] - 120 - 200 g / L of urea;

[0087] - 80 - 150 g / L of a thickener, such as an alginate thickener;

[0088] - 30 - 45 g / L of sodium carbonate;

[0089] - 2 - 5 g / L of a degassing agent, such as Croscolor PTM (supplier: Eurodye-CTC); and

[0090] - 10 - 20 g / L of an anti-reducing agent, such as Croscolor ARI (supplier: Eurodye-CTC); and

[0091] b-2) drying the fabric from step b-1) at a temperature of 120°C - 140°C for at least 1 minute.

[0092] The aqueous alkali solution preferably does not contain an organic solvent (i.e., water is the only solvent contained therein). As is well known in the field of textile chemistry, a "degassing agent", also referred to as an "air release agent" or a "deaerating agent", is a textile auxiliary that is designed to rapidly release air in a fabric, for example, during a fabric pretreatment / dyeing / post-treatment process. Due to their wetting, defoaming, and penetration properties, degassing agents remove hidden air traps in the fabric, including tightly packed and tightly woven fabrics, during the pretreatment process, thereby ensuring better ink permeability and performance. Examples of suitable degassing agents include known silicone-based degassing agents and sodium hexametaphosphate (SHMP). Examples of commercially available degassing agents include Croscolor PTM (supplier: Eurodye-CTC), sodium hexametaphosphate, DYNAPAN 360F (supplier: SILITEX), and TEGO Antifoam 1488 (supplier: EVONIK). As is well known in the field of textile chemistry, an "anti-reducing agent" is an oxidizing agent that prevents dyes, such as reactive dyes, from being reduced during a printing and dyeing process. As used herein, the term anti-reducing agent refers to an anti-reducing agent for reactive dyes and includes sodium m-nitrobenzenesulfonate and a degassing agent sold under the trade name Croscolor ARI.

[0093] Preferably, step b-2) is carried out by subjecting the fabric obtained in step b-1) to air at a temperature of 120°C - 140°C for less than 5 minutes, preferably less than 3 minutes, for example 2 minutes.

[0094] To fix a single reactive dye onto the fabric, the fabric obtained in step e) is preferably steam-treated at a temperature of 100°C - 105°C for 5 - 15 min, preferably 7 - 13 min. Accordingly, preferably step f) includes steam-treating the fabric at a temperature of 100°C - 105°C for 5 - 15 min.

[0095] In an alternative and more preferred embodiment, the reactive dyes present in one or more inks used in step c) and one or more inks used in step e) are bis-reactive dyes containing a first reactive functionality and a second reactive functionality. The first reactive functionality and the second reactive functionality are independently selected from a monochlorotriazine reactive functionality, a monofluorotriazine reactive functionality, a mono vinylsulfone reactive functionality, and a fluorochloropyrimidine reactive functionality. The bis-reactive dye can comprise, for example, a mono vinylsulfone reactive functionality and a fluorochloropyrimidine reactive functionality, or a monofluorotriazine reactive functionality and a mono vinylsulfone reactive functionality. Examples of suitable bis-reactive dyes include, but are not limited to C Yellow C-5G (supplier: Huntsman), Orange C-G (supplier: Huntsman), C Red C-2G (Supplier: Huntsman), C Red C-R (Supplier: Huntsman), C Blue C-4R (Supplier: Huntsman), C Turqouise C-GN (Supplier: Huntsman) and C Black C-N (Supplier: Huntsman). In this embodiment, step b) preferably includes:

[0096] b-3) Padding the uncolored fabric with an aqueous alkaline solution containing the following components:

[0097] - 15 - 35 g / L, preferably 15 - 25 g / L of sodium hydroxide;

[0098] - 60 - 80 g / L, preferably 70 g / L of sodium alginate; and

[0099] b-4) Drying the fabric from step b-3) at a temperature of 120°C - 140°C for at least 1 minute, preferably 2 minutes. The aqueous alkaline solution preferably does not contain an organic solvent (i.e., water is the only solvent contained therein). Preferably, step b-4) is carried out by passing the fabric obtained in step b-3) through air at a temperature of 120°C - 140°C. In order to fix the bis-reactive dye to the fabric, the fabric obtained in step e) is preferably held at a temperature of 20°C - 30°C for 5 - 9 hours. Accordingly, preferably step f) includes holding the fabric at a temperature of 20°C - 30°C for 5 - 9 hours.

[0100] In step d) of the manufacturing method of the present invention, the fabric obtained in step c) is dried to remove the solvent contained in one or more inks used for printing the back side of the fabric. Preferably, the drying is carried out by passing the fabric through hot air (e.g., air at a temperature of 120°C - 140°C).

[0101] The method claimed and described herein may optionally include step g):

[0102] g) Washing and drying the fabric. Washing may include soaping the fabric, followed by rinsing with water. The washed fabric may then be dried by exposure to hot air (e.g., air at a temperature of 120°C - 140°C).

[0103] Advantageously, steps c) - e) of the claimed and described method are fully automated and can be carried out on a digital printing press (e.g., the Reggiani ReNoir PRO digital printing press commercially available from EFI) connected to an air dryer to directly print the fabric.

[0104] A second aspect of the present invention relates to a method for manufacturing an indigo-free garment having the visual appearance of denim, which comprises the step of converting the obtained denim fabric into a garment. The garment having the visual appearance of denim is preferably selected from denim clothing, jackets, shirts, short skirts and long skirts. In a preferred embodiment, the garment having the visual appearance of denim is denim clothing.

[0105] The method for manufacturing an indigo-free garment as claimed and described herein may further comprise step h):

[0106] h) Post-finishing the garment.

[0107] The post-finishing step can change the appearance of the garment and thus customize the garment, for example, by removing color, creating contrast effects such as a worn visual effect, and / or softening the fabric surface. Preferably, when present, the post-finishing step involves laser treatment followed by water washing to remove the degraded reactive dyes. Laser treatment is a fast, precise and most environmentally friendly post-finishing method, which can customize the garment by creating incisions, holes, abrasions and "vintage" effects. Advantageously, in the manufacturing method described herein, no backstaining occurs.

[0108] A third aspect of the present invention relates to an indigo-free fabric having the visual appearance of denim. The fabric comprises at least 70 wt% cellulose fibers. The cellulose fibers comprise hydroxyl groups substituted by a structural moiety of the general formula Chr-L-, wherein Chr is a chromogen and -L- is a linking group that links the chromogen to the oxygen of the hydroxyl group. The back side of the fabric or a certain area of the back side has an inkjet-printed parallel straight line pattern, wherein preferably the distance between every two adjacent lines is 0.1 mm - 5 mm, and the width of the line is 0.1 mm - 2 mm. The front side of the fabric or a certain area of the front side has an inkjet-printed pattern having the appearance of denim. The indigo-free fabric as claimed and described herein has excellent color fastness properties and no risk of backstaining during the washing process.

[0109] The chromogen Chr is a chromogen derived from a reactive dye such as a mono-reactive dye or a bis-reactive dye. The linking group -L- that links the chromogen to the oxygen of the hydroxyl group comprises the bridging unit of the reactive dye and the remaining reactive functionality (e.g., the monochlorotriazine, monofluorotriazine, mono vinylsulfone of the reactive dye), which is obtained after nucleophilic substitution or nucleophilic addition with the hydroxyl group of the cellulose fiber. For example, if the reactive dye used for printing the fabric has the following structure:

[0110]

[0111] Then the chromogen Chr will have the following structure:

[0112]

[0113] And the linking group -L- will have the following structure:

[0114]

[0115] According to a preferred embodiment of the present invention, there is provided an indigo-free fabric as described herein, wherein the fabric is a woven fabric with diagonal ribs, and the parallel straight lines are printed at an angle of 60° - 120° relative to the ribs. Such an indigo-free fabric not only has a visual appearance but also has the texture of denim.

[0116] The indigo-free fabric described herein may have different colors and / or hues on the front side and the back side. For example, the indigo-free fabric may have at least two different hues on the front side, or the fabric may have a first hue on the front side and a second hue on the back side, with the first hue being different from the second hue.

[0117] According to a fourth aspect of the present invention, there is provided an indigo-free fabric having the visual appearance of denim, which is obtained by the methods claimed and described herein.

[0118] According to a fifth aspect of the present invention, there is provided an indigo-free fabric having the visual appearance of denim, which comprises the indigo-free fabric claimed and described herein. The clothing is preferably selected from denim, jackets, shirts, skirts, and long dresses, and more preferably denim.

[0119] To further illustrate the present invention, the following examples are provided. These examples are not intended to limit the scope of the present invention.

[0120] Examples

[0121] An uncolored woven fabric containing at least 70 wt% cellulose fibers (supplier: Evlox) was pad-dyed (absorption rate: 70 - 80%) with an aqueous alkali solution containing the following components: 120 g / L urea, 100 g / L alginate thickener, 30 g / L sodium carbonate, 2 g / L Croscolor PTM (supplier: Eurodye-CTC; degassing agent), and 10 g / L Croscolor ARI (supplier: Eurodye-CTC; anti-reducing agent).

[0122] After drying for 2 minutes at a temperature of 120°C - 140°C, the fabric roll is loaded onto a Reggiani ReNoir PRO digital printer (manufacturer: EFI) connected to an air dryer to inkjet print a parallel straight line pattern on its back side, the fabric is dried by exposure to hot air (120°C - 140°C) for 1 minute, and a pattern is inkjet printed on the front side of the fabric. The color containers of the printer are filled with SwissJet NR7 HD Yellow ink, SwissJet NR7 HD Magenta ink, SwissJet NR7 HD Cyan ink, and SwissJet NR7 HD Black ink, all commercially available from SPC Switzerland.

[0123] Thereafter, the fabric is steam treated at about 102°C for 8 minutes to fix the reactive dye.

[0124] The inkjet printed fabric is then soaped at a temperature of 95°C - 98°C and dried with hot air (120°C - 140°C) for 2 minutes.

[0125] Denim is made from the fabric obtained as described above.

[0126] Figures 1 and 2 are photos of two fabrics and denim obtained as described above (Figure 1: black fabric and denim; Figure 2: blue fabric and denim).

Claims

1. An indigo-free method for manufacturing a fabric having the visual appearance of denim, comprising the following steps: a) providing an uncolored fabric containing at least 70 wt% of cellulose fibers; b) contacting the uncolored fabric with an alkali solution; c) inkjet printing a parallel straight line pattern on the back side of the fabric or in a certain area of the back side of the fabric with one or more inks to provide the visual appearance of the back side of denim, wherein Each of the one or more inks contains a reactive dye and preferably has a viscosity of 5 cP - 9 cP, more preferably 6 cP - 7 cP, at a shear rate of 25 °C and 200 - 400 s -1 The viscosity at a shear rate of is 5 cP - 9 cP, more preferably 6 cP - 7 cP; d) drying the fabric; e) inkjet printing on the front side of the fabric or a certain area of the front side of the fabric with one or more inks to provide the visual appearance of the front side of denim, wherein Each of the one or more inks contains a reactive dye and preferably has a viscosity of 5 cP - 9 cP, more preferably 6 cP - 7 cP, at a shear rate of 25 °C and 200 - 400 s -1 The viscosity at a shear rate of 25 °C and 200 - 400 s is 5 cP - 9 cP, more preferably 6 cP - 7 cP; f) fixing the reactive dye to the fabric; and g) optionally washing and drying the fabric.

2. The method according to claim 1, wherein the distance between every two adjacent lines is 0.1 mm - 5 mm, and the width of the line is 0.1 mm - 2 mm.

3. The method according to claim 2, wherein the fabric is a woven fabric with diagonal ribs, and the parallel straight lines are printed at an angle of 60° - 120° relative to the ribs.

4. The method according to any one of claims 1 - 3, wherein the reactive dye present in one or more inks used in step c) and one or more inks used in step e) is a mono-reactive dye containing one reactive functionality, and the reactive functionality is preferably selected from a monochlorotriazine reactive functionality, a monofluorotriazine reactive functionality, and a mono vinyl sulfone reactive functionality.

5. The method according to claim 4, wherein step b) comprises: b-1) padding the uncolored fabric with an aqueous alkali solution containing the following components: - 120 - 200 g / L of urea; - 80 - 150 g / L of a thickener; - 30 - 45 g / L of sodium carbonate; - 2 - 5 g / L of a degassing agent; and - 10 - 20 g / L of an anti-reducing agent; and b-2) drying the fabric of step b-1) at a temperature of 120°C - 140°C for at least 1 minute.

6. The method according to claim 4 or 5, wherein step f) comprises steaming the fabric at a temperature of 100°C - 105°C for 5 - 15 min.

7. The method according to any one of claims 1 - 3, wherein the reactive dye present in one or more inks used in step c) and one or more inks used in step e) is a bis-reactive dye containing a first reactive functionality and a second reactive functionality, and the first reactive functionality and the second reactive functionality are independently selected from a monochlorotriazine reactive functionality, a monofluorotriazine reactive functionality, a mono vinyl sulfone reactive functionality, and a fluorochloropyrimidine reactive functionality.

8. The method according to claim 7, wherein step b) comprises: b-3) padding the uncolored fabric with an aqueous alkali solution containing the following components: - 15 - 35 g / L of sodium hydroxide; - 60 - 80 g / L of sodium alginate; and b-4) drying the fabric of step b-3) at a temperature of 120°C - 140°C for at least 1 minute.

9. The method according to claim 7 or 8, wherein step f) comprises holding the fabric at a temperature of 20°C - 30°C for 5 - 9 hours.

10. A method for manufacturing an indigo-free garment, preferably denim, having the visual appearance of denim, which comprises the step of converting the fabric according to any one of claims 1 - 9 into a garment.

11. An indigo-free fabric having the visual appearance of denim, wherein: the back side of the fabric or a certain area of the back side has an inkjet-printed parallel straight line pattern and the visual appearance of the back side of denim, the front side of the fabric or a certain area of the front side has an inkjet-printed pattern having the visual appearance of the front side of denim, and the fabric contains at least 70 wt% of cellulose fibers, the fibers containing hydroxyl groups substituted by structural moieties of the general formula Chr-L-, where Chr is a chromogen and -L- is a linking group that links the chromogen to the oxygen of the hydroxyl group.

12. The fabric according to claim 11, wherein the distance between every two adjacent lines is 0.1 mm - 5 mm, and the width of the line is 0.1 mm - 2 mm.

13. The fabric according to claim 12, wherein the fabric is a woven fabric having a diagonal rib, and the parallel straight lines are printed at an angle of 60° - 120° with respect to the rib.

14. The fabric according to any one of claims 1 - 13, wherein the inkjet-printed parallel straight line pattern is a piezoelectric inkjet-printed parallel straight line pattern, and the inkjet-printed pattern is a piezoelectric inkjet-printed pattern.

15. An indigo-free garment, preferably denim, having the visual appearance of denim, which comprises the indigo-free fabric according to any one of claims 11 - 14.

Images