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
  • D06P1/30—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
  • 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
  • D06P3/32—Material containing basic nitrogen containing amide groups leather skins
  • D06P3/3246—Material containing basic nitrogen containing amide groups leather skins using vat, sulfur or indigo dyes

Definitions

• the present invention relates to a process for dyeing leather with water-insoluble sulfur dyes in finely divided form, the dyeing being carried out from an aqueous liquor by the exhaust process without the addition of reducing agents and / or oxidizing agents.
• the water-insoluble sulfur dye with reducing agents is first converted into the water-soluble leuco form, which is drawn onto the cotton fiber and then oxidized on the fiber with oxidizing agents to the water-insoluble form.
• This well-known dyeing process is described, for example, in the following review articles: Melliand Textilber. 12 , 1314 (1973); Ullmann's Encyclopedia of Technical Chemistry, Volume 21, 65 (1982); Rev. Progress Coloring, Vol. 7, 80 (1976)).
• reducing agents no dye fixation occurs on the cotton fiber impregnated with finely dispersed sulfur dyes.
• water-soluble sulfur dyes can also be used for dyeing non-textile fiber materials, for example for dyeing chrome-tanned leather types (Rev. Progress Coloring Vol. 7, 83 (1976)).
• Colored salts are used as water-soluble sulfur dyes (K.Venkataraman, The Chemistry of Synthetic Dyes, Vol. VII, 36 (1974)) are obtained by the dyeing processes (Leather 178 , 27 (1976)) which are weak in color with good coloration (Leather 177 , 4406 (1975)) by the dyeing processes customary for acid dyes. Due to the low substantivity, these colored salts do not completely absorb leather and cause a high pollution of the dyeing waste water. Deeper dyeings with colored salts can only be obtained if special aids are used at the same time (German patents 3 601 721, 3 617 636), the aids in the dyeing waste water also being environmentally harmful.
• the present invention accordingly relates to a process for dyeing leather by the exhaust process, characterized in that water-insoluble sulfur dyes are used in dispersed form.
• pretreat leather prefferably to be dyed in the manner that is customary in the known exhaust process with water-soluble leather dyes (see, for example, K.Eitel "The Dyeing of Leather", Volume 5, pp. 269 ff., Umschau-Verlag, Frankfurt / m. (1987)).
• the process according to the invention itself is also advantageously carried out under the dyeing conditions which are customary for the known exhaust process with water-soluble leather dyes.
• the leather is dyed in an aqueous liquor which contains 20 to 400%, preferably 50 to 200% water, based on the fold weight of the leather, at a temperature of 20 to 100 ° C., preferably 30 to 60 ° C., with 0, 5 to 8%, preferably 1.5 to 6% of dispersed sulfur dyes in pigment form.
• the pH is preferably 3.8 to 5.5.
• the sulfur dyes can be combined in dispersed form with a dispersion of an inorganic or organic pigment and / or with a water-soluble acid or direct dye.
• Pigment dispersions are preferred in amounts of 0.1 to 6 % By weight, particularly preferably 0.1 to 3% by weight, based on the shaved weight of the leather.
• Water-soluble acid or direct dyes are preferably used in amounts of 0.1 to 6% by weight, particularly preferably 0.1 to 4% by weight, based on the shaved weight of the leather.
• the dispersed sulfur dyes can be combined in any order in the dye liquor with the other colorants mentioned. In addition, it is possible to mix the individual color components used before they are introduced into the dyeing liquor.
• the total dyeing time is normally 20 to 300, preferably 30 to 120 minutes.
• additives for example wetting or dispersing agents, leveling aids, color deepening agents and / or degreasing agents, can be added to the dyebath before, during or after the dyeing.
• salts such as sodium sulfite, sodium hydrogen sulfite or sodium pyrosulfite act as color deepening agents.
• the entire dyeing process is normally completed by lowering the pH of the dye liquor, to pH 3.8 to 5.5, preferably with formic acid.
• the added formic acid is allowed to act in the usual way for 10 to 60 minutes.
• the dyed leather is then prepared and finished in a manner known per se.
• the water-insoluble sulfur dyes used in the process according to the invention are in dispersed form and preferably have an average particle size of 10 nm to 2000 nm, particularly preferably 50 nm to 1000 nm.
• the finely divided sulfur dye dispersions are obtained in a manner known per se by grinding the water-insoluble sulfur dyes in suitable grinding units, for example in bead or sand mills, preferably in the presence of dispersants.
• Anionic surfactants and / or amphoteric surfactants and / or nonionic and / or cationic surfactants are preferred as dispersants.
• An overview of suitable surfactants can be found e.g. in Ullmann's Encyclopedia of Technical Chemistry, volume 16, 724-742 (1965), volume 22, 455-516 (1982), A 8, 315-350 (1987); E. Daruwalla, in K. Venkataraman, The Chemistry of Synthetic Dyes, Vol. VII, pages 86-92 (1974).
• sulfur dyestuff dispersions are used in the form of an aqueous dough, they can also contain organic solvents, e.g. from the series of mono- or polyhydric alcohols, polydiols or polyethylene, or polypropylene glycols, and / or contain preservatives known per se.
• Dispersed sulfur dyestuffs in pigment form are yellow, red, blue, green, brown and black sulfur dyestuffs, which are prepared using known processes, for example by baking or cooking melts of aromatic compounds with sulfur or alkali polysulfides, or by special processes, for example using disulphur dichloride, can be obtained.
• sulfur dyes based on copper phthalocyanine, perylene tetracarboxylic acid and oxazine dyes can also be used.
• Preferred sulfur dyes which can be used in finely divided, dispersed form by the dyeing process according to the invention are, for example, the sulfur dyes listed in the Color Index, Vol.5, 3rd Edition (1982) and (1987): Sulfur Black 1, Sulfur Black 2, Sulfur Black 6, Sulfur Black 8, Sulfur Black 9, Sulfur Black 11; Sulfur Brown 1, Sulfur Brown 10, Sulfur Brown 12, Sulfur Brown 15, Sulfor Brown 16, Sulfur Brown 20, Sulfur Brown 21, Sulfur Brown 31, Sulfur Brown 38, Sulfur Brown 46, Sulfur Brown 51, Sulfur Brown 52, Sulfur Brown 60, Sulfur Brown 93, Sulfur Brown 96; Sulfur Blue 2, Sulfur Blue 5, Sulfur Blue 6, Sulfur Blue 7, Sulfur Blue 10, Sulfur Blue 11, Sulfur Blue 12, Sulfur Blue 13; Sulfur Orange 2; Sulfur Green 2, Sulfur Green 3, Sulfur Green 5, Sulfur Green 8, Sulfur Green 9, Sulfur Green 12, Sulfur Green 19,
• sulfur or sulfur vat dyes are: Sulfur Black 1, Sulfur Black 2, Sulfur Black 6, Sulfur Black 8, Sulfur Black 11; Sulfur Brown 51, Sulfur Brown 96; Sulfur Green 36; Vat Green 14; Sulfur Red 10, Sulfur Red 14.
• Preferred pigments which can be used in combination with finely dispersed sulfur dyes of the type mentioned by the dyeing process according to the invention are, for example: black pigments based on elemental carbon, e.g. Pigment Black 6, 7, 8, 9, 10, Pigment Yellow 74, Pigment Orange 34, Pigment Orange 36, Pigment Brown 1, Pigment Red 112, Pigment Blue 15: 3. Pigment Black 7 is particularly preferred.
• Preferred acid and direct dyes which can be used in combination with finely dispersed sulfur dyes of the type mentioned by the dyeing process according to the invention are, for example: Solubilized Sulfur Black 1, Direct Black 168.
• the method according to the invention is for all types of leather, e.g. mineral or vegetable tanned grain, suede, suede or nubuck leather, suitable for beef, goat, sheep or pork.
• leather e.g. mineral or vegetable tanned grain, suede, suede or nubuck leather, suitable for beef, goat, sheep or pork.
• All types of leather have level dyeings of high color strength with good fastness properties, in particular good light fastness, wet fastness, wet and dry rubbing fastness, lick fastness, solvent fastness, sweat fastness and diffusion fastness compared to soft PVC.
• the good coloration of the leather dyed by the process according to the invention is surprising.
• percentages mean percentages by weight, based on the shaved weight (Examples 1 and 4) or on the dry weight (Examples 2 and 3) of the leather.
• the dyed leather is finished by rinsing with water, stretching, drying at 50 to 60 o C and millen.
• the dyed leather is finished in accordance with Example 1.
• the dyed leather is finished in accordance with Example 1.
• the dyed leather is finished in accordance with Example 1.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Coloring (AREA)

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Publications (1)

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• 1991
  • 1991-02-23 DE DE4105772A patent/DE4105772A1/de not_active Withdrawn
• 1992
  • 1992-02-07 EP EP92102027A patent/EP0501197A1/fr not_active Withdrawn
  • 1992-02-12 US US07/834,669 patent/US5240466A/en not_active Expired - Fee Related
  • 1992-02-20 BR BR929200559A patent/BR9200559A/pt not_active Application Discontinuation
  • 1992-02-21 JP JP4035289A patent/JPH06306775A/ja not_active Withdrawn
  • 1992-02-21 CA CA002061632A patent/CA2061632A1/fr not_active Abandoned

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Non-Patent Citations (2)

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