Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M13/00—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment
  • D06M13/322—Treating fibres, threads, yarns, fabrics or fibrous goods made from such materials, with non-macromolecular organic compounds; Such treatment combined with mechanical treatment with compounds containing nitrogen
  • D06M13/46—Compounds containing quaternary nitrogen atoms
  • D06M13/463—Compounds containing quaternary nitrogen atoms derived from monoamines
• • 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
  • D06P3/02—Material containing basic nitrogen
  • D06P3/04—Material containing basic nitrogen containing amide groups
  • D06P3/14—Wool
  • D06P3/141—Wool using vat or sulfur dyes
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M2101/00—Chemical constitution of the fibres, threads, yarns, fabrics or fibrous goods made from such materials, to be treated
  • D06M2101/02—Natural fibres, other than mineral fibres
  • D06M2101/10—Animal fibres
  • D06M2101/12—Keratin fibres or silk

Definitions

• the literature on wool discloses that the molecular grid of wool (Keratin) consists of polypeptide chains bound together by salt linkages and the covalent disulphide (-S-S) linkages. Such a literature further discloses that the disulphide bond is easily and readily degraded in the presence of alkali. Alkali disrupts the disulphide bonds and the fission of disulphide bonds results in the formation of thiol groups, which are very labile.
• indigo dyeing is carried out under highly alkaline pH values and that leuco indigo has an anionic charge.
• silk and wool have a tendency to lose their cationic property in presence of alkali. Both fibre and the dye being anionic under alkaline conditions, the net result is loss of dye- fibre affinity, lighter dyeing and poor fastness.
• Two of the silk properties that determine its colour behaviour are, firstly, very fine fibre fibrils and, secondly high fiber orientation. These fine fibrils produce a large fiber surface. Such a large fiber surface results in the colour yield being very low and about twice as much dye is required for achieving a given dark shade. Further, the fastness is poor. A large fiber surface also leads to a high dye-strike rate even at very low temperature resulting into rapid saturation at the fiber surface and unlevel dyeing. The high orientation of the fibres, which is a barrier to 5 diffusion, causes a very slow rate of further dye absorption, after the first rapid saturation.
• k is very easily chafed by abrasion particularly when the material is in wet swollen state.
• the polypeptide -chains of silk fibroin may hydrolyze in boiling I o water or in steam. This becomes critical in the presence of acids or alkalis. Higher concentrations of alkalis rapidly dissolve silk and wool. Degradation of silk and wool is determined by pH and the type of alkali. The mechanical stress leads to splicing of silk threads, which is severe and irreparable damage.
• Still another object of this invention is to propose a novel process for the dyeing of wool, silk or blends thereof with indigo, which reduces the severity of dyeing conditions.
• a further object of this invention is to propose a novel process for the dyeing of wool, silk or blends thereof with indigo, which avoids any damage being caused to wool or silk.
• a mordanting of wool and silk in the form of cationization on line enhances dye-fibre affinity by virtue of imparted cation ⁇ cxiye-cornbitiing sites for indigo which is anionic in alkaline media.
• Such mordanting also reduces the heterogeneity in the substrate and offer thereby level dyeing.
• Wool and silk are sensitive to alkali and might degrade significantly when in contact with alkali particularly caustic soda for any appreciable length of time. In case of wool, such a normally negative point is instead taken advantage of by using generated thiol groups as additional dye combining sites.
• a process for the pretreatment of wool, silk or blends thereof comprising the step of online cationization of silk, wool or blends thereof to render it receptive to indigo dyeing by imparting a cationic charge and generating dye-combining sites.
• the treatment comprises in the step of cationization by passing wool, silk or blends thereof through pretreatment baths and then subjecting to the step of a passage in air, which is preferably online.
• the online pretreatment could be effected either at ambient temperature or at sub-ambient temperature,
• the pretreatment bath comprises 3- to 120 gpl, and preferably 3 to 80 gpl of cationizing compound and 3 to 25 gpl of caustic soda either separately or in admixture. Wool, silk or their blends is subjected to a treatment in the pretreatment baths for 5 to 30 seconds each and to the
• step of dyeing of silk or wool with indigo subsequent to the pretreatment step comprises in passing in tandem the pretreated silk, wool or blend through a plurality of 15 indigo dye baths following the dip-squeeze-air (oxidation) steps.
• the dye bath contains (leuco) indigo, soda ash sodium hydroxide, sodium hydrosulphite and known chemical auxiliaries.
• wool and silk have a tendency to lose its cationic charge in the presence of alkali.
• the addition of alkali to the dye bath is necessary in order to render the dye soluble.
• the pretreatment step renders silk or wool receptive to anionic leuco dye by virtue of imparted cationization and generated dye combining sites in the substrate.
• each dye bath contains 1.0 to 3.5 gpl indigo and upto 8 dye baths may be provided.
• the passage of wool or silk through each dye bath is for a period of 5 to 30 seconds each followed by the step of squeez and oxidation for a period of 30 to 180 seconds for each step of oxidation.
• the dye-bath recipe contains soda ash mostly and between 15-20 gpl, in place of caustic soda. The latter is used for fine tuning of dye bath pH.
• the caustic soda and the cationizing chemical in the pre-treatment are kept at subambient treatment in accordance with on embodiment of this invention. This is to reduce the severity of the process and help substrate retain its original strength. Reference is made to the online pretreatment step in distinction to a batch process.
• One of the aspects of the present invention resides in the online pretreatment step which provides a short period of contact of wool, silk of its blends with caustic soda and cationizing chemicals. It is known that wool, silk or its blend is sensitive to caustic soda. Thus, one of the aspects of the present invention is to ensure that the wool, silk or its blends is not deteriorated or damaged by the pretreatment step, which is ensured by a reduced contact period with the cationizing chemicals by such an online step.
• the nitrogen content of the cationizing chemical viz., 3-chloro-2- hydroxy propyl trimethyl ammonium chloride is 9.18%.
• the 0.35% increase in nitrogen content in cationized sample would therefore mean 5.8 gram of cationizing chemical was added up to 100 grams of wool.
• the nitrogen increase in case of silk was 0.2% which means 3.3 gms of cationizing chemical was deposited onto 100 gms of silk.
• the pretreatment apparatus contains Box 1 and Box 2 with squeeze rollers SRl therebetween.
• First box Box 1 may contain cationizing chemical solution followed by aeration thereafter which allows time for cationizing chemical to penetrate well into wool/ silk substrate.
• the second box Box 2 may contain caustic soda solution also followed by aeration.
• Aeration allows time for reaction between wool/ silk and cationizing chemical in the presence of caustic soda.
• Box 1 may contain both cationizing chemicals and caustic soda.
• the second box Box 2 in such an instance could be empty-or could be used for a water-rinse Indigo dyeing then follow in tandem, with conventional and known steps of indigo dyeing, viz., dip-squeeze-air.
• the pretreated substrate then passes through a plurality of dye boxes, for example 1 to 8 dye boxes, followed each time by aeration.
• the substrate is then subjected to post dyeing wash off in wash boxes and then passed through drying cans.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Coloring (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Treatment Of Fiber Materials (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (3)

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Family Applications (1)

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Cited By (2)

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Citations (4)

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• 2006
  • 2006-06-27 WO PCT/IN2006/000216 patent/WO2007000775A2/en not_active Ceased
  • 2006-06-27 JP JP2008519140A patent/JP2008544111A/ja active Pending
  • 2006-06-27 EP EP06756266.0A patent/EP1913196B1/en not_active Not-in-force
  • 2006-06-27 US US11/994,202 patent/US20100205751A1/en not_active Abandoned
• 2014
  • 2014-08-04 JP JP2014158732A patent/JP2015007305A/ja active Pending

Patent Citations (4)

Non-Patent Citations (1)

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