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
  • 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
  • D06P1/0004—General aspects of dyeing
  • D06P1/0016—Dye baths containing a dyeing agent in a special form such as for instance in melted or solid form, as a floating film or gel, spray or aerosol, or atomised 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
  • D06B19/00—Treatment of textile materials by liquids, gases or vapours, not provided for in groups D06B1/00 - D06B17/00
  • D06B19/0088—Treatment of textile materials by liquids, gases or vapours, not provided for in groups D06B1/00 - D06B17/00 using a short bath ratio liquor
  • D06B19/0094—Treatment of textile materials by liquids, gases or vapours, not provided for in groups D06B1/00 - D06B17/00 using a short bath ratio liquor as a foam
• • 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
  • D06P1/22—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 vat dyestuffs including indigo
• • 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
  • D06P1/22—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 vat dyestuffs including indigo
  • D06P1/228—Indigo
• • 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
  • D06P1/96—Dyeing characterised by a short bath ratio
  • D06P1/965—Foam dyeing
• • 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
  • D06P3/003—Special processes of dyeing or printing textiles, or dyeing leather, furs, or solid macromolecular substances in any form, classified according to the material treated 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
  • 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

Definitions

• the present invention relates to the technical field of dyeing with indigo.
• Indigo has been known since ancient times to be a useful dye for dyeing textile materials.
• it is used particularly for dyeing warp yarns in the manufacture of denim articles such as blue jeans for example.
• Indigo is water insoluble and has no affinity for fiber and therefore must first be reduced to the water-soluble leuco form, which has moderate affinity for fiber and which, after it has gone onto the material to be dyed, is oxidized back to the indigo pigment.
• Sodium dithionite is one example of a reducing agent used to reduce the indigo, but other reducing agents such as thiourea dioxide and hydroxyacetone can also be used. However, it is more advantageous to effect the reduction through catalytic hydrogenation to obtain a solution of leucoindigo, which can be metered directly into the dyebath, see EP 0 692 042 B1 .
• Another disadvantage is that the dyeing machines required are very large and have a warp yarn sheet length of 105 to 500 meters.
• WO 2008/056256 A1 discloses a device and a continuous dyeing process with indigo.
• EP 1 591 578 A2 discloses a process wherein a cellulosic textile material has applied to it, on one side at least, a leucoindigo-containing foam and is subsequently exposed to an oxidizing medium, i.e., preferably air.
• the foam which is produced in a foam generator, is applied to the textile material by means of nozzles. It is a particular advantage of this process that the front and back of a fabric can be dyed with different dyes or at least in different hues, providing special effects.
• dyeing warp yarns or an open sheet of warp yarn by following this process is a difficult undertaking in practice and, more particularly, does not lead to uniform dyeing of warp yarns.
• the present invention relates to a process for dyeing cellulosic warp yarns with indigo by applying a leucoindigo foam to the warp yarns and subsequently oxidizing the leucoindigo to indigo, wherein the warp yarns are led through an entry opening into a sealed foam chamber and have leucoindigo foam applied to them therein before they reemerge from the foam chamber through an exit opening, the longitudinal tension of the warp yarns being closed loop controlled such that they are in a state of free suspension within the foam chamber, wherein the warp yarn sheet is very substantially cooled down immediately before entry into the foam chamber.
• Cellulosic warp yarns herein are cotton warp yarns in particular, but also warp yarns composed of blends of cotton with materials such as polyester and polyamide.
• the leucoindigo foam is obtainable for example by foaming an aqueous solution of leucoindigo by means of an inert gas in a commercially available foam generator.
• the aqueous solution of leucoindigo is obtainable by reduction of indigo with a reducing agent, in particular with sodium dithionite.
• Indigo solution may preferably be fed directly to the foam generator from the tank container in which the indigo solution is supplied by the manufacturer. It may be the case that additional water also has to be supplied to the foam generator. This additional water is preferably first degassed and then mixed with an inert gas, preferably nitrogen.
• the inert gas used is preferably nitrogen, but can also be any other inert gas. It is particularly advantageous for the foam generator to be admixed with carbon dioxide as well as the inert gas, particularly nitrogen, and thereby to lower the pH of the foam and enhance the affinity of the leucoindigo for the warp yarn.
• carbon dioxide is preferably used in amounts of 5% to 80% by volume, more preferably in amounts of 20% to 50% by volume.
• the pH of the foam is preferably in the range from 12.6 to 10.4 and more preferably in the range from 11.6 to 11.0.
• foaming is effected with the assistance of a foam-former.
• foam-formers include in particular anionic or nonionic surfactants which are known and commercially available. Suitable surfactants are discernible from EP 0 162 018 for example.
• Foaming can further be effected in the presence of further auxiliaries.
• Wetting agents capable of enhancing the penetration of the leucoindigo into the warp yarn can be added for example.
• Such wetting agents are commercially available, and mixtures of mono- and diesters of phosphoric acid with, for example, 2-ethylhexanol are particularly useful.
• Wetting agents are preferably used in amounts of 1% to 20%, more preferably 2% to 8%, based on the mixture to be foamed.
• Foaming can further be effected in the presence of auxiliaries which bring about a fastness improvement and also of auxiliaries which minimize yellowing of the indigo-dyed textile material under the influence of harmful gases such as ozone or nitrogen oxides.
• auxiliaries are available.
• Useful fastness-improving auxiliaries include for example reactive resins capable of crosslinking on the surface of the textile material.
• reactive resins capable of crosslinking on the surface of the textile material.
• epichlorohydrin-modified polyamides or polyamidoamines will be found particularly advantageous here.
• Useful yellowness inhibitors include for example condensation products of fatty acids with hydroxyalkylamines.
• Preferred reaction components here include for example stearic acid, tallow fatty acid and oleic acid and also di- and triethanolamine and also N-(aminoethyl)ethanolamine. It is additionally advantageous when the nitrogen in the reaction product is additionally quaternized in a second reaction step.
• Quaternizing agents used include, for example, dimethyl sulfate or methyl p-toluenesulfonate.
• polymers having long-chain hydrocarbyl chains and forming barrier layers also find use as yellowness inhibitors.
• hydrocarbyl chain should preferably have a length of more than 12 carbon atoms in order that an effective barrier layer can be formed.
• auxiliaries mentioned are preferably used in amounts of 1% to 15% and more preferably 2% to 8%, based on the mixture to be foamed.
• Foam generators are known and can operate statically or preferably dynamically. They are described in DE 25 23 062 and US 4,118,526 for example and are commercially available.
• the foam generator It is preferable to maintain the foam at a constant temperature, in which case temperatures of 15 to 70°C particularly of 25 to 40°C are particularly preferred. It is particularly helpful for this purpose to equip the foam generator with a double-walled housing through which a heat transfer medium circulates to maintain the desired temperature.
• the leucoindigo foam is applied to the warp yarns in the foam chamber.
• the foam chamber is equipped with or connected to at least one suitable leucoindigo foam applicator device which is supplied from the foam generator.
• the applicator device used can be any device which presses or sucks the foam uniformly onto the warp yarns. Such applicator devices are known and described in DE 2523062 for example.
• Preferred applicator devices are those which include a parabolic distribution chamber, as described for example in US 4,655,056 and EP 1 065 308 A2 . It is preferable, in the process of the present invention, for a plurality of applicator devices, in particular 2 to 5, to each be disposed transversely to the warp yarn sheet at short distances apart, so that the foam chamber is supplied with foam uniformly over the entire width of the warp yarn sheet. It is advantageous in this connection for all applicator devices to be supplied from one foam generator.
• the foam chamber is ideally small in dimensions and encloses the warp yarn sheet as closely as possible.
• the entry and exit openings for the warp yarn sheet are advantageously slot shaped such that the warp yarn sheet can pass through without touching at the top or bottom.
• gas locks to be disposed upstream of the entry opening and downstream of the exit opening.
• the warp yarn sheet is very substantially cooled down immediately before entry into the foam chamber. More particularly, the warp yarn sheet is cooled down to temperatures of 25 to -10°C, more preferably 15 to -5°C.
• Cooling can be effected by following any known cooling process, but preference is given to using contact cooling which operates via cooling cylinders. It is particularly preferable to cool through brief direct contact of the warp yarn sheet with a liquid coolant, for example liquid ammonia or, in particular, liquid nitrogen.
• a liquid coolant for example liquid ammonia or, in particular, liquid nitrogen.
• the warp yarn sheet is subjected to a pretreatment before dyeing.
• auxiliaries and/or colorants can be applied to the warp yarn sheet.
• auxiliaries are for example the commercially available wetting agents described above and also the fastness improvers also described above.
• Colorants are for example customary sulfur, vat, reactive and direct dyes.
• the pretreatment typically is followed by a drying step which in turn is followed by the dyeing step.
• the process of the present invention provides in particular an acceptable depth of shade on a single pass of the warp yarn sheet through the foam chamber. As a result, appreciably smaller volumes of wastewater are generated, so that appreciable economic advantages are achieved.

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Publications (2)

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• 2009
  • 2009-06-02 BR BRPI0914987A patent/BRPI0914987A2/pt not_active IP Right Cessation
  • 2009-06-02 EP EP09772251A patent/EP2288747B1/en active Active
  • 2009-06-02 MX MX2010013459A patent/MX2010013459A/es not_active Application Discontinuation
  • 2009-06-02 WO PCT/EP2009/056709 patent/WO2010000551A2/en active Application Filing
  • 2009-06-02 CN CN2009801184387A patent/CN102046875B/zh not_active Expired - Fee Related
  • 2009-06-05 TW TW98118716A patent/TW201030210A/zh unknown

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