WO2022183093A1 - Plage de colorants soufrés et procédés, et fils et tissus produits à partir de ceux-ci - Google Patents

Plage de colorants soufrés et procédés, et fils et tissus produits à partir de ceux-ci Download PDF

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Publication number
WO2022183093A1
WO2022183093A1 PCT/US2022/018073 US2022018073W WO2022183093A1 WO 2022183093 A1 WO2022183093 A1 WO 2022183093A1 US 2022018073 W US2022018073 W US 2022018073W WO 2022183093 A1 WO2022183093 A1 WO 2022183093A1
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Prior art keywords
dye
stage
sulfur
range
seconds
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PCT/US2022/018073
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English (en)
Inventor
Alpesh Patel
Heath Colwell
Jr. Darryl J. Costin
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CleanKore, LLC
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Publication of WO2022183093A1 publication Critical patent/WO2022183093A1/fr

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    • 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
    • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
    • D06P1/30—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using sulfur dyes
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06B—TREATING TEXTILE MATERIALS USING LIQUIDS, GASES OR VAPOURS
    • D06B23/00—Component parts, details, or accessories of apparatus or machines, specially adapted for the treating of textile materials, not restricted to a particular kind of apparatus, provided for in groups D06B1/00 - D06B21/00
    • D06B23/24—Means for regulating the amount of treating material picked up by the textile material during its treatment
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06B—TREATING TEXTILE MATERIALS USING LIQUIDS, GASES OR VAPOURS
    • D06B3/00—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating
    • D06B3/04—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating of yarns, threads or filaments
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06B—TREATING TEXTILE MATERIALS USING LIQUIDS, GASES OR VAPOURS
    • D06B3/00—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating
    • D06B3/10—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating of fabrics
    • D—TEXTILES; PAPER
    • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
    • D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
    • D06L1/00—Dry-cleaning or washing fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods
    • D06L1/12—Dry-cleaning or washing fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods using aqueous solvents
    • 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
    • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
    • D06P1/0024—Dyeing and bleaching in one process
    • 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
    • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
    • D06P1/0032—Determining dye recipes and dyeing parameters; Colour matching or monitoring
    • 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
    • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
    • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
    • D06P1/445—Use of auxiliary substances before, during or after dyeing or printing
    • 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
    • D06P3/00—Special processes of dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form, classified according to the material treated
    • D06P3/58—Material containing hydroxyl groups
    • D06P3/60—Natural or regenerated cellulose
    • D06P3/6025—Natural or regenerated cellulose using vat or sulfur dyes
    • 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
    • D06P5/20—Physical treatments affecting dyeing, e.g. ultrasonic or electric
    • D06P5/2005—Treatments with alpha, beta, gamma or other rays, e.g. stimulated rays

Definitions

  • the present invention generally relates to fabric dyeing, such as fabric dyeing using sulfur dyes.
  • a process is provided which provides a dyed yarn having reduced dye penetration and a white core.
  • the process involves modification of existing sulfur dye ranges in order to more efficiently and in an environmentally improved method produce dyed fabrics.
  • the invention also is directed to yams dyed on dye ranges through use of the process, and fabrics formed from the dyed yarns.
  • Sulfur dyes are typically utilized when the desired color is a shade of blue that is darker than can be readily made with indigo dyes alone. Other times, sulfur dyes are used to achieve colors that do not involve blue at all. Most commonly, black or grey colors call for the use of sulfur dyes, but other colors are achievable as well.
  • Sulfur dye is different from indigo dye in many ways; and fading characteristic is one of them.
  • the molecules of indigo are relatively small when compared to the molecules of both the cotton fibers and the molecules of sulfur dyes. How well a dye tends to maintain its bond to the fiber (typically cotton or cotton blend) is generally referred to as fastness. How well a dye has fasted to the yarn determines the amount of energy, water, or chemistry that is necessary to remove the dye from the yarn after oxidation occurs. With the larger molecules of sulfur dyes, sulfur dyes have much stronger bonds with the yarn fibers, meaning the sulfur dyes tend to resist fading from both wash and wear more than indigo dyes.
  • a dye range is an array of equipment that is used together to dye yarns. There are many stages to a dye range, and each dye range may differ from another. When a design involves a darker shade than is easily achievable with indigo alone but still involves the color blue and intentional fading, two dyeing technologies, indigo dyeing and sulfur dyeing, may be blended. There are several range configurations used for blending indigo and sulfur dyes in the industry:
  • Some dye ranges are equipped with the ability to make sulfur bottom, indigo top. This involves first exposing yams to a sulfur dye process (immersion and oxidation) and then exposing the yams to the indigo dye process. 2 Ranges can also be equipped to apply indigo as the bottom dye, and sulfur dye last, referred to as indigo bottom, sulfur top.
  • Ranges are often equipped to apply sulfur dyes alone, without indigo dyes. This is particularly appealing when the goal is a very dark grey or black color.
  • sulfur dyes can be made to be almost any color.
  • the sulfur chemistry is identical, but a different chromophore is used to achieve the different colors.
  • CleanKore which is not specific to the color, but rather the methods used to achieve the dyeing results.
  • the dye ranges where the indigo dye and sulfur dye alternate repeatedly in layers are, e.g., sulfur indigo, indigo sulfur, or indigo sulfur indigo, demonstrating both unique dye ranges as well as techniques.
  • sulfur indigo indigo sulfur
  • indigo sulfur indigo indigo sulfur indigo
  • the dye range may even be equipped to have drying stages between dyeing stages with the thought being that dry yarns that are then subsequently immersed in the tank that follows will more quickly pull dye into the yams.
  • sulfur dyeing In a design environment that often favors an appearance of wear, distress, or color loss, sulfur dyeing has a significant disadvantage in that it is substantially more difficult to remove the dyes whether that be using oxidation, laser irradiation, or mechanical abrasion. This in turn results in an inordinate amount of energy used to achieve a particular appearance while using sulfur dyes. Sometimes the dye proves so difficult to remove that sulfur dyeing is avoided altogether.
  • the present invention provides a solution to the issue of excessive dye penetration of the yarns through the implementation of several embodiments.
  • the inventive processes also referred to herein as CleanKore
  • CleanKore have proven to reduce dye penetration in the sulfur dyeing process.
  • the optimization of dye penetration, as well as the minimization of dye penetration variation for sulfur dyeing processes, results for the first time in yams that form a fabric that is significantly more receptive to laser abrasion, manual abrasion, and oxidizer treatments used to remove color based on the style specification.
  • the processes disclosed herein increase yarn dye consistency and optimization comes with fewer rejected garments resulting in chargebacks throughout the supply chain.
  • the present invention identifies, improves upon, and modifies one or more steps in existing conventional sulfur dye ranges to achieve dyeing of the yam while retaining a white core at the center of the yarn.
  • FIG. 1 which shows cross-sections of five different dyed yarns at different levels of dye penetration, the peripheral portions of the yarns are dyed (black), and the center of the cross-section remains white (not dyed).
  • the yams 1.1 and 1.2 are dyed completely, or nearly completely to the core, leaving very little original white core to be revealed.
  • Yarns 1.1 and 1.2 when viewed as a cross-section, may appear to be solid in color, or possibly lighter in color toward the core but still obviously dyed through the core, thus providing an example of a yam that has significant dye penetration and, to the unassisted eye, still appears quite dark.
  • the core of the yarns 1.1 and 1.2 may be an even lighter color, or possibly even have a few fibers within the center that appear white, but the excessive penetration creates a barrier impenetrable by laser abrasion.
  • Yarn 1.3 is an example of a core that with the unassisted eye may appear to have a white, or significantly lighter shade core, but the dye penetration is still impenetrable by laser abrasion as it extends too far from the perimeter of the yarn.
  • Yarn 1.4 is an example of a yam that is dyed without consistency as measured from the perimeter of the yarn. This yam may appear exceptional to the naked eye, displaying a larger area of the yarn that is undyed revealing lighter shades of dye, or even large areas of white in the yams. These are some of the least desirable yarns, as they result in streaking and inconsistencies after weaving, with uncontrolled portions being dyed vs undyed.
  • Yarn 1.5 is an example of the goal of ring dyeing: low yarn penetration while still displaying consistency in dye penetration, with a dark shade on the exterior perimeter of the yarn and a white or nearly white core. This type of yarn readily receives laser energy sufficiently to replace potassium permanganate in the manufacturing process as the chemical bleaching is unnecessary. Yarn 1.5 is most comparable to the yarns dyed with the present invention.
  • Cotton fibers are naturally occurring, with the randomness of the fibers introducing some variables, which, when paired with inconsistencies in twist, etc., result in some variation in dye penetration relative to the perimeter of the yarn, but the results of the inventive technology are to minimize this effect as much as possible.
  • implementation of the present invention results in consistent dye penetration about 10% to about 35% of the cross-sectional area of the yarn.
  • Dying the periphery with controlled depth penetration and allowing the core to remain white is advantageous, particularly when the resulting fabric is subjected to laser abrasion, manual abrasion, and/or oxidizer treatments to remove color.
  • the present invention modifies the scouring stage (or phase), the scour rinsing stage, the dyeing stage, the oxidation stage, and/or the dye rinsing phase of existing dye ranges.
  • the modifications may be applied individually or any combinations thereof to existing dye ranges to reduce and optimize sulfur dye penetration in order to form dyed yams resembling Yarn 1.5..
  • FIG. l is a drawing showing cross-sections of five different dyed yams with different dye penetration levels
  • FIG. 2A is a micrograph showing an example of a conventionally dyed sulfur black yarn; [017] FIG. 2B is a drawing rendition of FIG. 2A;
  • FIG. 3 A micrograph showing an example of a sulfur black yam dyed using the present invention
  • FIG. 3B is a drawing rendition of FIG. 3 A;
  • FIG. 4A is a photograph of a denim garment with the left leg (wearer’s right leg) made from conventional sulfur dyed fabric and the right leg (wearer’s left leg) made from the CleanKore sulfur dyed fabric;
  • FIG. 4B is a drawing rendition of FIG. 4A;
  • FIG. 5 is a diagram showing a dye range
  • FIG. 6 is a drawing showing an exemplary vat in the dye range
  • FIG. 7 is a drawing showing a yam being threaded through the vat of FIG. 6 using all of the rollers.
  • FIGS. 8.1-8.8 are drawings showing different configurations of a yam being re-threaded through the vat of FIG. 6 using some of the rollers while skipping others.
  • Dye ranges include many large containers called vats 102 (or boxes or tanks). These vats 102 are commonly filled with thousands of liters of chemicals, water, and/or dye. The vats 102 serve different purposes and therefore have chemicals that differ from vat to vat.
  • rollers 104 nip rollers 104a and regular rollers 104b are referred herein collectively as rollers 1044 that range from a few inches to a couple of feet in diameter.
  • rollers 104 are found within the vats 102, as well as outside the vats 102. Nip rollers 104a pull the yarns through the range 100 while also squeezing moisture from the yams 106; and regular rollers 104b are simply rollers that the yams 106 pass over. Nip rollers 104a will be addressed in greater detail below. The yarns 106 pass over (or under) the various rollers 104 as they progress through the range 100.
  • An exemplary vat 102 and associated rollers 104a, 104b are shown in FIG. 6. A plurality of regular rollers are used and are denoted in FIG. 6 with subscript numerals.
  • the dye range 100 first scours the yarns 106 to wash them of impurities, such as oils and waxes, in scouring vats (tanks or boxes) 102a.
  • the scouring process (scouring stage) prepares the yarns 106 for dyeing.
  • the yams 106 are washed, typically a vat filled with water that is flowing with fresh water causing contaminated water to overflow to a drain, in a scour rinsing vat 102d to remove chemicals used in the scour vat 102a from the yarns 106 (scour rinsing stage).
  • the yams 106 are then dyed in a plurality of dye vats 102b (dyeing stage). After each dye vat 102b, the yarns 106 are exposed to air by passing through a plurality of regular rollers 104b above the dye vats 102b to allow the dye to oxidize (oxidation stage). After dyeing, the yams 106 are passed through rinsing vats 102c to remove excess dyes on the yams 106 (dye rinse stage). Once rinsed, the yarns 106 are dried, e.g., such as by using drying cans 108. [028] The dye range 100 begins with the scouring process.
  • the scouring process traditionally involves one or more scouring tanks or vats 102a within which yams 106 are passed over and under a series of rollers 104a, 104b.
  • the scouring vats 102a are filled with water and chemicals, such as caustic soda, chelate agents, and wetting agents, such as PrimasolTM from Archroma, for example; and composed of a series of regular rollers 104b that cause the yams 106 to be immersed in the chemicals as the yarns 106 move through the range 100.
  • the yarns 106 are then rinsed in water.
  • the scour rinse is desirable and removes the caustic and contaminants before the yarns 106 are passed through the dye vats 102b containing dye chemistries.
  • Dye vats 102b are large tanks containing a dye solution (or dye chemistry), within which the yarns 106 pass over a series of rollers 104.
  • the size of the dye vats 102b is typically over 250 gallons each, with some as large as 700 gallons.
  • the yarn path over or under regular rollers 104b in dye vat 102b typically immerses the yarns 106 in the dye chemistry.
  • the yams 106 are processed through a nip roller 104a and then enter a dye oxidation stage. It is during the dye oxidation stage that the yarns 106 are exposed to air through a series of regular rollers 104b. Sulfur and indigo dyes are not water- soluble. During the immersion stage, the dyes are reduced to a soluble state through the removal of oxygen. Once the yams 106 exit the immersion vats 102b and begin the exposure to oxygen, the dye returns to an insoluble state, effectively bonding the dye to the yams 106.
  • the yarns 106 proceed to a dye rinse stage, which typically occurs in one or more dye rinse vats 102c.
  • This dye rinse stage rinses the yarns 106 of excess dye and removes dye that has not fasted to the yams 106 during the oxidation phase.
  • the number of dye rinse vats 102c at a given mill on a given range 100 may vary between one to three.
  • the present invention involves modifying conventional dyeing ranges and processes to produce a yam with a sulfur dyed periphery, while its core remains white.
  • the CleanKore technology also provides significant savings in chemicals, water, and energy compared to conventional sulfur dyeing processes.
  • the modifications include, but are not limited to, changing the scouring stage, limiting sulfur dye immersion, rethreading the yarn path, reducing sky oxidation, expose sulfur dyes to water for oxidation, and/or limiting water rinses (dye rinse stage) after dyeing.
  • a sulfur black dye style was issued as a “control.”
  • This control had a scour (often referred to as prewet) box 102a immersion time of 22 seconds and scour chemistry consisting of 6 grams per liter of wetting agent and 20 grams per liter of caustic (100% concentration).
  • Wetting agents act as surfactants and are available commercially.
  • One exemplary wetting agent is Primasol NF, distributed by Archroma.
  • the caustic in the scour vat 102a was reduced to a mere 4.5 grams per liter (100% concentration) and the wetting agent was reduced to 2 grams per liter.
  • the immersion time was also lowered from the conventional 22 seconds to approximately 9 seconds at room temperature.
  • the CleanKore range for scour immersion time is between 4 and 18 seconds, with a preferred range of 7 seconds to 12 seconds.
  • Air or “sky” time can be understood by those skilled in the art to be the time yarns 106 spend on rollers 104 outside of each respective immersion. These air oxidation times were typically 52 and 22 seconds, respectively. These dwell or sky times were reduced to 5 seconds from the exit of the yarns from the nip roller on the scour tank to the immersion into the scour rinse, because the time the yarns 106 spent in the air only afforded the chemistry on the yarns 106 extended time to impart their effect.
  • the dwell time was reduced to about 5 seconds, but the general CleanKore approach is to significantly lessen or minimize this dwell time, depending on the limitations of each individual range.
  • the dwell time may be capable of being reduced to 5 seconds or less.
  • Other dye ranges may require a dwell time that is longer.
  • the minimization of this sky time was to better control or limit the amount of time the scour chemistry may dwell or continue to act upon the yams 106.
  • the caustic chemicals used in the scour process remove the waxes and oils naturally found in cotton yams, thereby reducing their desirable hydrophobic properties.
  • Wetting agents act as a penetrant, dramatically increasing the efficacy of the caustic, which again works to reduce the hydrophobic properties naturally occurring in cotton yarns.
  • CleanKore technology works through modifications of yarn characteristics, as well as dyeing chemistries, and exposure to chemicals. By employing yarns of a higher twist, in a range of 4.5- 5.0 Twist Multiple (TM) and reducing the exposure of the yarns 106 to chemicals that would encourage core penetration, a larger, whiter core is retained with the CleanKore techniques.
  • Reducing yarn 106 exposure to the scouring chemicals is done through modification of the time the yarns 106 spend in contact with the chemicals in each of the vats by changing the threading or pathing of the yarns associated with scouring, dyeing, and rinsing stages. Also, for the scouring, dyeing, and/or rinsing stages, these methods involve the changing of concentration of the chemicals, the temperature of the process, and, when possible, the expediency and efficacy of the oxidation as described later in this application. Some or all of the chemicals can be eliminated as well. For example, the caustic may be removed from the scour tank 102a, or the scour process could be entirely skipped, and the yarns 106 could go directly to a rinse tank.
  • the caustic could be removed from the scouring stage entirely, and the wetting agent, e.g., a wetting agent such as Primasol NF distributed by Archroma, reduced to a mere 0.5 grams to 2.0 grams per liter.
  • the purpose was to optimize the least amount of wetting agent required while still removing streaks from the dye application on the yams.
  • Dye ranges are typically set up with dye immersion times of 18-24 seconds per dye vat 102b at normal operating speeds. Normal operating speed may depend on the specific dye range and may range from 5-32 meters/second. Some ranges may operate from 5-10 m/s, while others from 15 to 25 m/s.
  • Another inventive step is to, however possible, limit the yam exposure to dye chemistry to a range of 2 to 14 seconds per immersion. Ideally, that range is between 4.0 and 11 seconds.
  • the reduction in sulfur dye immersion is, therefore, an embodiment of the CleanKore technology.
  • These abbreviated immersion times may occur in a single dye tank 102b, or they may be repeated in multiple dye tanks 102b in order to achieve the necessary shade.
  • the yarn immersion times may be adjusted due to many variables, but one of the most significant is the range type. Slasher ranges can and typically do expose the yarns to much higher tensions throughout the range compared to rope ranges. With increased yam tension, the dye is slower to be absorbed into the yarns. In the preferred range, the 6 seconds to 14 seconds is preferred for slasher style ranges with higher tensions, and 3.0 to 12.0 seconds is preferred with the rope style range with the lower yarn tension.
  • Slasher ranges generally involve operators painstakingly dragging individual yarns (thousands of them) through the dye range.
  • Rope ranges involve a multitude of bundles of yarns called ropes. Rope ranges cannot be driven with high tension as the tension reduces the capability of the dye to flow through the fibers of the ropes. Because slashers involve individual yarns, they can operate at higher tension because each yam is equally exposed to the dye chemistry.
  • the dye ranges typically operation at tensions high enough to get the yarns through effectively, but not so high as to break them (for slasher ranges) or such that the dye cannot penetrate the center of the rope (for rope ranges).
  • the primary method used in adjusting the immersion times and another embodiment of the invention is what the inventors refer to as “rethreading” various parts of the dye range, such as the tanks 102a, 102b, 102c and conventional air oxidation stage as the examples depict in FIGS. 8.1 - 8.8.
  • Dye ranges are configured such that the yarns conventionally follow a default path involving all rollers across the dye range, as shown in FIG. 7.
  • the Applicants have traveled to dozens of locations in a dozen different countries and have yet to experience a dye range threaded in such a way that could be described as anything other than “normal.” Normal, in this context, means that they follow the maximum length path prescribed by the manufacturer of the dye range, e.g., as depicted in FIG. 7, where all of the rollers 104 are used in threading of the yarns 106.
  • the re-threading of these yarn paths is a novel embodiment necessary in solving the dye penetration problem that arises from excessive immersion times which are conventional.
  • the inventive re-threading process involves skipping some rollers 104b (which particular to each specified range configuration) to shorten the path and time through stages.
  • the different exemplary ways to rethread the yarns 106 through a vat 102 is depicted in FIGS. 8.1 - 8.8.
  • FIG. 8.1 re-threads the yarns 106 by skipping rollers 104b3 and 104bs;
  • FIG. 8.2 skips rollers 104b2 and 104b5;
  • the preferred method is to thread the yarns 106 in such a way that a bit too much time would be spent in the dye tanks 102b if run at the conventional maximize productivity, which is yet another embodiment of the invention.
  • Changing the path of the yarns 106 by rethreading the range is an embodiment of the CleanKore process.
  • the rethreading of the yarns 106 may be used to reduce the time the yams 106 spend in any stage of the dye range.
  • One of the novelties of this invention is in recognizing that the air oxidation stages that follow the dye immersion, although sufficient for indigo dyes, are too slow for sulfur dye.
  • the air oxidation cycle can be too slow to oxidize the sulfur dye quickly enough, such that the sulfur dye only oxidizes on the perimeter of the yarn for the sulfur dyeing process.
  • Conventional threading paths and sulfur dyeing techniques involve exposing the yarns 106 to sulfur dye vats 102b and then exposing the yams to air for 50 - 150 seconds (oxidation stage), and oftentimes repeating these two steps more than once.
  • the yams 106 processed conventionally with the conditions disclosed prior involved a sky oxidation time of 56 seconds. Rethreading the yarns 106 through the dye tanks 102b or other tanks does not, by itself, address dye oxidation.
  • the yarns 106 are not skyed at all or are only skyed or oxidized conventionally in the air for much briefer periods, such as 1-30 seconds.
  • the air oxidation time (or sky time) should be reduced to 30 seconds or less. Ideally this sky oxidation time is minimized, or as close to 0 seconds as possible, where the process still yields acceptable results with limited sky time, such as 1-30 seconds.
  • the elimination or reduction of the air oxidation time significantly reduces the time the dye chemistry may continue to migrate toward the core and is an embodiment of the invention.
  • the time spent in air oxidation is a tunable component with additional rethreading of the yams 106 on the roller path, depending on the yarn twist, yam size, desired shade, and chemicals involved in the dye range. Incremental additions to the specified range of time spent in air oxidation will result in incrementally diminished gains in white core retention but reducing or eliminating air oxidation time is an embodiment of the CleanKore process.
  • the water oxidation may use tanks added to the process or existing tanks that are removed from the process.
  • each time the yarns 106 are exposed to sulfur dye they are subsequently exposed to water oxidation in a vat containing water.
  • the introduction of freshwater oxidation immersion stages is a novel concept.
  • traditional sulfur dyeing involves the yarns 106 passing from the dye vat(s) 102b to air oxidation (repeating several times)
  • the CleanKore process minimizes or eliminates air oxidation.
  • the yarns 106 are exposed to water oxidation, and only then are optionally exposed to a subsequent sulfur dye immersion, depending on shade requirements.
  • Immersion times in the water oxidation stage can be higher or lower than the time range disclosed above based on the efficacy of the waterflow to the water oxidation boxes to maintain a preferred basic pH of 11.5 or less , but should be exposed to an oxidizing rinse with water after a sulfur dye immersion.
  • This control of pH is achieved with the increase of water flow to this water oxidation stage as necessary to maintain the desire pH.
  • rinses can be measured and determined minimally effective dye reducing chemistry when the pH of said vat is below approximately 10.5 and the mV (oxidation-reduction potential measurement) is -550 or higher (for the sake of clarity, examples of a greater number could be -440, -340, -240, -140, or 0).
  • Increasing the water flow to the rinse tanks could reduce or solve the issue with excessive dye penetration with indigo following this same inventive step, but this would not resolve the significantly lighter shades and wasted indigo. With room temperature water (tap water without additional heating) oxidation, the sulfur dye is too insufficiently reduced to make the increased yarn exposure problematic.
  • Sulfur dye specifically designed to be soluble at lower temperatures is, however, an exception and results in a need for a higher water flow to the water oxidation stage to maintain a pH value of >10.2 and even perhaps shorter exposure or immersion times. Deviations from this specification may result in an improved core compared to conventional sulfur dyeing, but still are not optimal in comparison to the specified parameters of the CleanKore process. Exposure to water oxidation following dye immersion for sulfur dyes is then an embodiment of the CleanKore process.
  • sulfur dye operates with a pH of 12.6 to 13.2. CleanKore applications work more proficiently at a pH in the sulfur dye tank of less than 12.6, with an ideal pH of 12.0 to 12.5. 6. Limit rinses post-dye
  • an embodiment of the CleanKore technology reduces rinsing after sulfur dyeing stages with the objective of reducing reliance on water for the production of dyed yarns.
  • FIG. 3 reveals a white yam core with a dark ring of black sulfur dye around the perimeter of the yarn produced with the parameters disclosed for the CleanKore technology.
  • Yarns dyed using the CleanKore techniques outlined throughout this application can be expected to perform similarly while exhibiting excellent dye fastness. However, and most importantly, significantly less energy or chemical is required to remove the perimeter of the dye to reveal partially or wholly the white or near white core of the yarn 106.
  • the average savings across three trials was (per 10,000 meters) 22,572 liters of water, 5704 kWh of energy, and 590.7 kg of chemicals. This is a major benefit of the invention which is not realized with the prior art processing of sulfur dyes.
  • the preferred immersion time in the scour stage is from 3 seconds to 14 seconds, where 3 seconds to 12 seconds is ideal for a slasher style range with increased tension, and the preferred immersion time in scour on a rope range is from 6 seconds to 14 seconds.
  • This dramatic reduction in scour chemistry, temperature and immersion duration significantly improves the wax retention in the core of the yarn, which in turn favorably reduces dye penetration inwards towards the core.
  • the three heated scour rinse boxes 102d that previously followed the scouring stage were replaced by a single, room-temperature scour rinse box 102d.
  • This single remaining rinse box 102d was maintained with a flow rate of approximately 2500 liters per hour, but this flow rate, instead of being fixed, was adjusted to maintain a pH of the scour rinse box of ⁇ 10.5.
  • the monitoring of scour rinse boxes 102d for pH levels is a novel CleanKore embodiment. This concept is a unique approach to lessening the impact of the caustic and wetting agents on the yarn center’s original waxy makeup. The reduced time in the rinse tanks also plays a role as well. [053] III.
  • Dye box set up for the conventional sulfur dyed yarns [054] After processing the yarns through the scour and scour rinse stages, the conventionally dyed yarns skipped the next eight (8) dye vats] and were then subjected to two successive dye boxes 102b.
  • the eight skipped dye boxes were part of the existing dye range, which was used for both indigo dye, which was typically associated with a larger number of tanks, and sulfur dye. While any two boxes could be used on the dye range, it was preferred that the boxes at the beginning of the range were skipped, such that the time, from when the yarns 106 left the last dye box to the time it reached the rinse tanks that follow, was minimal.
  • This threading path can result in a variety of immersion times based on the specifications of the dye box 102b, as dye boxes are unique in depth and length from range to range. Where the dye boxes 102b are too deep and/or too long, an alternative may be a threading path, such as the one depicted in FIG. 8.4, which results in a shallow immersion, typically providing a minimal immersion time.
  • a threading path such as the one depicted in FIG. 8.4
  • the yarns 106 can alternatively be threaded through a box designated for a different purpose, such as a rinse tank. The rethreading, however, may be used with any tank in the dye range.
  • the tank chosen to serve as a dye tank simply requires a source of heating the sulfur dye solution, as well as a supply from chemical feed tanks, also referred to as “the kitchen.”
  • This inventive step reduces the time that the yams 106 are exposed to dye, as well as the caustic and other reducing chemistries, for example, sodium sulfide (a sulfur dye reducing agent) within the dyestuff, which all affect dye penetration.
  • the dye feed to the dye tank 102b was increased from 220 grams of dye per liter to 250 grams per liter to safely offset the reduction in immersion time while still achieving the target shade.
  • the reducer was reduced to 10 grams per liter of water (from 350 grams per liter); the wetting agent was eliminated; and the 50% concentration caustic was reduced from 40 grams per liter to a mere 2.5 grams per liter.
  • the pH of the dye tank 102b was controlled by the amount of caustic in the tank to a range of 11.7 to 13.1. The caustic is used in the dye tank 102b to achieve a near oxygen free environment to make the dyes water soluble.
  • the yarn 106s passed from dye immersion, through the respective nip rollers 104b, and then, as quickly as possible, exposed to a water bath bypassing the air oxidation stage to the extent possible (some ranges, because of their roller configuration, require at least some air oxidation) in order to immerse the dye and yams into a water vat to serve as an oxidation bath and rinse at room temperature (tap water temperature with no additional heat added) for approximately 3-12 seconds, but preferably 5-10 seconds. Less time in the water rinse/oxidation stage would result in a drop in oxidation thoroughness and decrease efficacy of loose dye removal.
  • the water flow rate in the water rinse/oxidation box is, according to the CleanKore technology, monitored to maintain a pH of ⁇ 10.5. This often requires a water flow of at least twice the capacity of the tank being used, which is an embodiment. For example, if a water rinse/oxidation tank is 800 liters, a freshwater flow rate of 1600 liters per hour may be used to maintain a pH of ⁇ 10.5. Variables on the dye range impact the contamination rate of the tank and consequently the rinse tank flow rate can be adjusted accordingly.
  • Some examples of these variables could be range speed (higher speed results in more yam passing through the vat in a given amount of time, requiring higher flow) and yarn diameter (larger diameter yarn carries more chemistry from preceding tanks, lower diameter yarn carries less chemistry from preceding tanks).
  • This flow rate can be adjusted according to the pH, often resulting in even more water savings when compared to using a greater number of tanks, even when the flow rates to individual conventional boxes may be lower. CleanKore uses fewer tanks with the disclosed flow rate often results in a water savings.
  • the conventionally dyed yarn passed through three (3) 2,000-liter dye rinse stages with an average immersion time of 21 seconds with a flow rate of 3000 liters per hour each, heated to 70°C, 70°C, and 50°C respectively, resulting in tremendous energy consumption.
  • Sulfur dye achieves increased solubility with temperatures above 70°. So, in addition to wasted energy, these higher immersion times and temperatures increase the likelihood of dye migration towards the core of the yams 106, as these temperatures approach the temperatures required for dyeing conditions with sulfur dyes.
  • the CleanKore technology used with sulfur black dye required two room temperature water rinse/oxidation vats. These were conducted in two 2,000-liter tanks, with the flow rate in the first tank maintained at 3,000 liter per hour and the flow rate in the second tank reduced to 2400 liters per hour.
  • the yarns 106 were immersed in the dye rinse tanks 102c for 7 and 11 seconds, respectively.
  • the shorter duration of the first dye rinse tank 102c served to reduce the contamination level within that tank, making the replenishment of freshwater much more effective and maintaining a relatively clean oxygen-rich water in which the sulfur dye can be quickly oxidized (here dye rinse and oxidation occurred in the same tank (water rinse/oxidation process)). Reduction in the contamination level of all water rinse/oxidation tanks is an important element of the CleanKore technology.
  • the monitoring of dye rinse boxes 102c for pH levels (pH ⁇ 10.5) is a novel CleanKore embodiment.
  • the yarns 106 are then processed through a longer duration dye rinse cycle from approximately 11 seconds to 18 seconds for the yarns 106 to experience increased strain (the strain yarns experience as passed over rollers 104a, 104b) through the roller path, as well as exposure to the water to further remove loose dyes not removed from the first dye rinse vat 102c.
  • the process of the yams 106 passing over rollers 104a, 104b serves to wring dye from the yarns 106. This is selectively used to rid the yarns 106 of some of the dye in the first dye rinse tank 102c without the over contamination that can result from a longer rinse immersion in this stage.
  • Nip rollers 104a are placed at the exit of each immersion stage for scouring boxes 102a, scour rinse boxes 102d, dye boxes 102b, and dye rinse boxes 102c. These nip rollers 104a are responsible for squeezing the chemistry from the yarns 106 and redepositing them into the vat from which the yarns just emerged. Increasing the nip pressure improves the efficacy of this wringing action to reduce the amount of chemistry carried on the yarns into the subsequent stages.
  • the conventionally dyed yarns had nip pressures of 60 PSI throughout their range.
  • CleanKore selectively increases the nip pressures following the immersions that have the greatest impact on dye penetration.
  • the nip pressures on the scouring box 102a nip roller 104a were increased to 85 PSI or maximum pressure allowable on a given range to further eliminate caustic from the yarn 106, reducing the time the caustic acts on the yam 106, as well as reducing the contamination into the scour rinse tank 102d.
  • the dye immersion and dye rinse stages also had their nip pressures increased in a similar fashion to lessen the duration that the chemistries imparted their chemical impact on the yarn 106.
  • the increase in nip pressures is another embodiment.
  • the CleanKore parameters ware determined through rigorous testing, retesting, and analysis of yarn dyeing techniques.
  • the heating of the scour tanks certainly increases the efficacy of the caustic in ridding the yarns of impurities, but the Applicants realized that this was counterproductive to retaining a white core with a thin circumferential ring of appropriate dark dyed yarns.
  • This same lengthy approach has been applied to the dye stages, the nip rollers 104a between the stages, the scour rinse stage, the water purity in the water rinse/oxidation tanks, as well as the chemistries and even distributors of chemicals and their variations in the quality of chemical products.
  • the CleanKore technology involves methods that take centuries-old dye technology and significantly improve the process with major advancements in the technology for dyeing denim.
  • a dye range 100 can be installed nearly anywhere in the world at an expense in excess of one million USD ($1,000 000.00 USD) and carries with it no more improvements in yarn core preservation than what was experienced previously. It is through the manipulation of these dye ranges and chemistries as, for example, is itemized throughout this application that results in modern and novel dye results that have been unprecedented.
  • One embodiment of this invention is the application of sulfur black dye in the scouring tank 102a. It is common that a light (l%-4%) application of sulfur dye is applied in the scour tank 102a, which is referred to as sulfur bottom, where the yarns 106 would subsequently be exposed to indigo dyes.
  • the purpose of the sulfur application in a sulfur bottom scenario is to have a darker version of indigo dye with a low (l%-4%) add on of sulfur dye. This results in indigo dye being applied on a grayish yam rather than a white yarn, which aids in creating a darker blue appearance.
  • This is referred to as sulfur-scour combination dyeing.
  • the yarns 106 enter the sulfur-scour combination dyeing dry.
  • the yarns 106 then proceed to the end of the dye range 100, bypassing each of the tanks associated with dyeing and dye rinsing, to the extent possible on any given dye range 100 (the scour and dyeing process is combined).
  • Successful experiments have been conducted practicing this method with a mere 1 gram per liter of wetting agent.
  • the dye chemistry was supplemented with 3 - 7 grams per liter of caustic for a 5% - 20% shade (the amount of dye on the yam) which resulted in excellent white core retention in the yam.
  • these yarns could also be transferred from a dye rinse/oxidation process to additional sulfur dye immersions before a final water rinse/oxidation in order to achieve shades darker than can be achieved in the single scour/dye vat.
  • the same sourced cotton on a slasher range may require 2 grams per liter to counter with the reduced penetration of chemicals associated with the increased yarn tension on the slasher range, which can be determined by the presence or lack of streaking in the dyed and undyed portions of the yams.
  • the CleanKore method involves using the least amount of wetting agent as possible while still avoiding streaking.
  • Another embodiment of this invention is the tuning of the caustic according to pH.
  • Dye ranges all over the world consist of machinery that is polluted with chemistry to varying extents and even the water being used varies in the pH levels.
  • caustic is added to maintain a pH of 11.2-12.2 within the scour box 102a, with a preferred range of 11.6-12.0. Maintaining this range helps control the pH in the scour rinse tank 102d. Excess chemistry in any given stage increases the chance of contamination in subsequent stages.
  • the means to maintaining this pH goal can be varied, but a couple of examples are as follows:
  • the scour tank 102a may be filled with water from a source which would normally introduce caustic, to take the contamination of all equipment into consideration.
  • This water could be sampled and taken to a lab to be measured for pH levels.
  • Caustic could be added incrementally until the pH reaches the desired goal, within the range of 11.2 to 12.2.
  • the caustic dosage can be determined as necessary to maintain the pH from the mixing tanks to the actual scour box.
  • the caustic dosage is determined by the machine based on the target pH.
  • the equipment typically has a feed of caustic with a valve that opens to feed caustic into the tank as necessary to maintain the target pH.
  • the scour chemistry could simply be mixed with a very light dosage of caustic, such as 0.5 gram per liter to 3.0 grams per liter, and then incrementally raised until the pH reaches the target range.
  • a very light dosage of caustic such as 0.5 gram per liter to 3.0 grams per liter
  • the maintenance of this pH range and methods to do so are embodiments of the CleanKore technology.
  • Washing and abrasion technologies are used to reveal varying degrees of contrast between the dyed cast (the background color) of the garment and the original color of the yam, as it was before receiving dye.
  • Acid wash, stone wash, laser abraded, hand sand, sandblasted and laser-pattern jeans are all types of garments that consist of combinations of dark, dyed colors and varying levels of lighter shades that resemble white or lighter shades throughout the garment.
  • these garments have been made conventionally resulting in extraordinary measures being necessary to reveal these lighter colors.
  • These measures utilize staggering amounts of freshwater, require the application of hazardous chemicals, such as potassium permanganate and sodium hypochlorite, electricity, millions of hours of manual labor resulting in countless repetitive injuries, all in attempts to reveal both a dark and light color within garments.
  • the ring dye perimeter is substantially smaller and consistent, meaning less of the yarn cross-section is dyed.
  • CleanKore dyeing technology has shown repeatedly and consistently to reduce dependence on water, energy, and chemicals in the production of yarns and increased production in the washing and dry processing of denim garments. This reduced dependence on natural resources makes for a more environmentally friendly solution with reduced costs at the mill, at the garment laundry, and eventually for the brands which sell garments constructed with CleanKore technology.
  • FIG. 4 shows a garment constructed with a conventionally dyed sulfur fabric on the left leg after it had been laser abraded and then washed. The same garment is constructed with CleanKore fabric on the right leg of the garment.

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Abstract

La présente invention concerne de manière générale la teinture au soufre de tissus. En particulier, l'invention concerne un procédé qui fournit un fil teint au soufre ayant une pénétration de colorant réduite et un âme blanche. Le procédé implique la modification de plages de colorants soufrés existantes afin de produire des tissus teints, plus efficacement et dans un procédé amélioré sans danger pour l'environnement. Le procédé consiste à modifier le temps d'immersion, la température, le pH et/ou l'oxydation de colorant de plages existantes de colorants soufrés. Les fils obtenus peuvent ensuite être tissés en étoffes utilisées pour produire des vêtements.
PCT/US2022/018073 2021-02-26 2022-02-28 Plage de colorants soufrés et procédés, et fils et tissus produits à partir de ceux-ci WO2022183093A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5514187A (en) * 1994-09-20 1996-05-07 Burlington Industries, Inc. Reduced indigo dye penetration
US10508388B1 (en) 2017-05-15 2019-12-17 Revolaze, LLC Yarn material with a white center
WO2020096650A1 (fr) * 2018-11-07 2020-05-14 Revolaze, LLC Procédé amélioré de teinture en anneau et matériau produit selon ce procédé

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5514187A (en) * 1994-09-20 1996-05-07 Burlington Industries, Inc. Reduced indigo dye penetration
US10508388B1 (en) 2017-05-15 2019-12-17 Revolaze, LLC Yarn material with a white center
US10711397B1 (en) 2017-05-15 2020-07-14 Revolaze, LLC Yarn material with a white center
WO2020096650A1 (fr) * 2018-11-07 2020-05-14 Revolaze, LLC Procédé amélioré de teinture en anneau et matériau produit selon ce procédé

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