Bleaching and dyeing; fluid treatment and chemical modification – Bleaching – Chemical
Reexamination Certificate
2001-05-11
2002-06-25
Kopec, Mark (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Bleaching
Chemical
C008S102000, C008S401000, C008S573000, C008S137000, C008S138000, C510S281000, C510S321000, C510S393000, C548S259000
Reexamination Certificate
active
06409771
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel method of removing excess dye from newly printed or dyed fabric or yarn as well as a system and a composition for use in the method.
2. Description of Related Art
Printing and dyeing of textiles is carried out by applying dyes to the textile by any appropriate method for binding the dyestuff to the fibres in the textiles. Excess soluble dyestuff not bound to the fibres must be removed after dyeing to ensure fastness of the dyed textiles and to prevent unwanted dye transfer during laundering of the textiles by the consumer.
Generally, a large amount of water is required for complete removal of excess dye. In a conventional process the printed or dyed textile is first rinsed with cold water, then washed at high temperature with the addition of a suitable additive to decrease back-staining, like poly(vinylpyrrolidone) (PVP). The process is repeated until a satisfactory amount of dyestuff (and thickeners) has been removed. PVP can be added to reduce back-staining during rinsing, but this compound does not bleach the dye and is relatively expensive. Furthermore, the waste liquor from a conventional process tends to be strongly colored and may represent a disposal problem, which is not reduced by the use of PVP.
WO 92/18687 discloses a method of bleaching excess dye from printed or dyed fabric by treating with a liquor containing an enzyme exhibiting peroxidase activity or oxidase activity, an O
2
or H
2
O
2
source as applicable, and optionally an additional oxidizable substrate, such as a metal ion, a halide ion or an organic compound, such as a phenol.
However, the concentrations of such additional substrates necessary for enzymatically bleaching the excess dye in the rinse liquor may present a risk of bleaching the dyed textiles themselves.
Accordingly, it is an object of the present invention to provide a method for removing or bleaching excess dye without bleaching the dyed textile This is achieved by a process for removal of excess dye from newly manufactured printed or dyed fabric or yarn comprising treatment with a rinse liquor comprising
at least one enzyme selected from the group consisting of enzymes exhibiting peroxidase activity or laccase activity,
an oxidation agent, and
at least one mediator selected from the group consisting of aliphatic, cyclo-aliphatic, heterocyclic or aromatic compounds containing the moiety >N—OH, and
optionally additives.
In the present invention the term “mediator” means an additional oxidizable substance improving the bleaching performance.
By suitable combination of mediator and enzyme it is possible to avoid bleaching of the dyed textile while bleaching dyes in solution, thereby reducing the amount of unbleached dye deposited on the fibres and thus increasing the wet fastness of the dyed or printed textile.
By this process it is furthermore possible to reduce the number of rinsing steps and the temperature of the rinsing water in the rinsing steps compared to the conventional processes, thereby saving energy and costs.
Another object of the present invention is a system for removal of excess dye from newly manufactured printed or dyed fabric or yarn, which is a multi-component system comprising at least one enzyme selected from the group consisting of enzymes exhibiting peroxidase activity or laccase activity, an oxidation agent, and at least one mediator selected from the group consisting of aliphatic, cyclo-aliphatic, heterocyclic or aromatic compounds containing the moiety >N—OH, and optionally additives, such as rinsing additives.
The components of the system may be combined as a solution, a slurry or granulates depending on the specific enzymes and mediators selected.
A further object of the present invention is the use of the components specified above for the preparation of a multi-component system for removal of excess dye or print from newly manufactured fabric or yarn.
DETAILED DESCRIPTION OF THE INVENTION
Fabric or Yarn
The process of the invention is applicable to all types of textile materials, both natural fibres and synthetic fibres as well as blends thereof. Typical examples are cellulosic fibres (cotton and flax), modified cellulose fibres (e.g. acetate and triacetate), protein fibres (e.g. wool and silk), polyamide fibres (e.g. nylon 6 and 6,6), polyester fibres (e.g. poly(ethylene terephthalate)) and acrylic fibres.
The process of the invention may be applied to dyed yarn, to knitted, woven or non-woven fabric, or to garments made from dyed and/or printed fabric, especially garments made from differently colored material.
Printing Method
The process of the invention is suited for excess dye bleaching after any kind of textile printing. Examples of commonly used techniques are printing on a Rotation film, a Rouleaux, a Flash film, or a Transfer film device. After printing the dye is fixed on the textile by e.g. steaming or treatment with hot air.
Dyeing Method
The process of the invention is suited for excess dye bleaching after any kind of dyeing. The dyeing of textiles is for example carried out by passing the fabric through a concentrated solution of dye, followed by storage of the wet fabric in a vapour tight enclosure to permit time for diffusion and reaction of the dye with the fabric substrate prior to rinsing off un-reacted dye. Alternatively, the dye may be fixed by subsequent steaming of the textile prior to rinsing.
The process applies to any kind of dyes, such as reactive dyes.
Enzyme
Enzymes exhibiting peroxidase activity or laccase activity are those which by using hydrogen peroxide or molecular oxygen, respectively are capable of oxidising a variety of compounds, such as phenols and aromatic amines.
According to the invention the concentration of enzyme is 0.005 to 5 mg enzyme protein per 1 of rinse liquor, preferably, 0.02 to 2 mg enzyme protein per 1 of rinse liquor, more preferably 0.05 to 1 mg enzyme protein per 1 of rinse liquor. According to the liquor ratio, this may be translated to dosages of enzyme per kg of fabric, e.g. at a liquor ratio of 10:1, the most preferred enzyme dosage is from 0.5 to 10 mg enzyme per kg of textile fabric.
Peroxidase Activity Exhibiting Enzymes
An enzyme exhibiting peroxidase activity may be any peroxidase comprised by the enzyme classification (EC 1.11.1.7), or a haloperoxidase, such as a chloride peroxidase (EC 1.11.1.10) or any fragment or synthetic or semisynthetic derivatives thereof exhibiting enzymatic activity (e.g. porphyrin ring systems or microperoxidases, cf. e.g. U.S. Pat. No. 4,077,768, EP 537 381, WO 91/05858 and WO 92/16634). Such enzymes are known from microbial, plant and animal origins.
Preferably, the peroxidase employed in the method of the invention is producible by plants (e.g. horseradish or soybean peroxidase), in particular soybean peroxidase, or by microorganisms, such as fungi (including filamentous fungi and yeasts) or bacteria.
Some preferred fungi include strains belonging to the subdivision Deuteromycotina, class Hyphomycetes, e.g., Fusarium, Humicola, Tricoderma, Myrothecium, Verticillum, Arthromyces, Caldariomyces, Ulocladium, Embellisia, Cladosporium or Dreschlera, in particular
Fusarium oxysporum
(DSM 2672),
Humicola insolens, Trichoderma resii, Myrothecium verrucana
(IFO 6113),
Verticillum alboatrum, Verticillum dahie, Arthromyces ramosus
(FERM P-7754),
Caldariomyces fumago, Ulocladium chartarum, Embellisia alli
or
Dreschlera halodes.
Other preferred fungi include strains belonging to the subdivision Basidiomycotina, class Basidiomycetes, e.g. Coprinus, Phanerochaete, Coriolus or Trametes, in particular Coprinus cinereus f. microsporus (IFO 8371),
Coprinus macrorhizus, Phanerochaete chrysosporium
(e.g. NA-12) or Trametes (some classes previously called Polyporus have been renamed to Trametes), e.g.,
T. versicolor
(e.g. PR4 28-A).
Further preferred fungi include strains belonging to the subdivision Zygomycotina, class Mycoraceae, e.g. Rhizopus or Mucor, in particular
Mucor hiemalis.
Some preferred bacteria include stra
Damhus Ture
Schneider Palle
Vogt Uwe
Garbell Jason I.
Kopec Mark
Lambiris Elias J.
Mruk Brian P.
Novozymes A/S
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