Bleaching and dyeing; fluid treatment and chemical modification – Dye or potential dye composition – additive – treatment,... – Mixed dyes – noncomplexed
Reexamination Certificate
1999-11-22
2001-09-11
Einsmann, Margaret (Department: 1751)
Bleaching and dyeing; fluid treatment and chemical modification
Dye or potential dye composition, additive, treatment,...
Mixed dyes, noncomplexed
C008S642000, C008S650000, C008S652000
Reexamination Certificate
active
06287349
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a process for dyeing fibrous substrates which comprises the steps of: providing a fibrous substrate; providing at least one sulfur dye; providing at least one reduction stable direct dye; and applying said reduction stable direct dye to said fibrous substrate in the presence of a suitable reducing agent.
BACKGROUND OF THE INVENTION
As has been known for many years, sulfur dyes are advantageously used in the dyeing and/or printing of cellulose fiber materials and/or cellulosic blended textile fibers. In traditional dyeing processes the sulfur dyes are applied in the alkali soluble (pre)reduced form, i.e. “leuco state”, and are brought in contact with the cellulosic fibers in one of a variety of methods and subsequently oxidized in order to achieve color development and/or impart a degree of dye fastness to the dyed cellulosic textile substrate.
Reducing agents traditionally employed for the application of sulfur dyes are in particular: sodium hydrogen sulphide, sodium sulfide and sodium polysulphides. Other chemical reducing agents that do not contain sulfide ions (i.e. “non-sulfide” reducing agents) known to be useful for the reduction of sulfur dyestuffs include: sodium borohydride, formamidinesulphinic acid, glyceraldehyde, hydroxyacetone, hydroxylamine sulfate, lignin sulphonates, sodium formaldehydesulphoxylate, sodium hydrosulphite, thioglycolic acid, and various reducing sugars.
The prior art teaches the processing of only vat and sulfur dyes in a reducing medium. It has been believed that the use of direct dyes in such conditions would result in the destruction of the chromophore. Direct dyes may have been used to shade sulfur dyeings but not applied in combination with sulfur dyes dyed simultaneously in a reduction medium.
SUMMARY OF THE INVENTION
A process for dyeing fibrous substrates which comprises the steps of: providing a fibrous substrate; providing at least one sulfur dye; providing at least one reduction stable direct dye; and applying said reduction stable direct dye and sulfur dye to said fibrous substrate in the presence of a suitable reducing agent.
Further, it has been surprising to find that these reduction stable direct dyes can be processed without a sulfur dye present. This results in a process for dyeing fibrous substrates which comprises the steps of: providing a fibrous substrate; providing a reduction stable direct dye; and applying said reduction stable direct dye to said fibrous substrate in the presence of a suitable reducing agent.
Still further, it has been surprising to find that reduction stable direct dyes can be processed with vat dyes and optionally also sulfur dyes. The result is a process for dyeing fibrous substrates which comprises the steps of: providing a fibrous substrate; providing at least one vat dye; providing at least one reduction stable direct dye; and applying said reduction stable direct dye and vat dye to said fibrous substrate in the presence of a suitable reducing agent.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A process for dyeing fibrous substrates which comprises the steps of: providing a fibrous substrate; providing at least one sulfur dye; providing at least one reduction stable direct dye; and applying said reduction stable direct dye and sulfur dye to said fibrous substrate in the presence of a suitable reducing agent.
The fibrous substrate is selected from the group of: cellulosic fibrous material, cellulosic-mixed fiber materials and blends of cellulosic fibers with synthetic non-cellulosic fiber. By “cellulosic fibrous material” it is to be understood a substrate which comprises cellulose fibers and which may further comprise non-cellulosic fibers, which may be mixed with the cellulosic fibers, and is preferably textile material. Contemplated non-cellulosic fibers include semi-synthetic and fully synthetic polymeric fibrous material including, but not limited to, cellulose acetates, polyamides (alkyl and aromatic), polyesters, polyolefin, polyacrylonitrile, as well as others known in the art as useful in forming mixed fiber blends with cellulose fibers. Further, the fibers may be in any conventional form, including, but not limited to, raw stock, threads, yarns, or in semi-finished product form, that is to mean, in the form of twisted hanks or skeins of yarns or fibers, spooled threads, knitted or woven textile such as fabrics, as well as in final product form such as garments.
The sulfur dyes (S) which may be used in accordance with the process of the invention include those which are either provided in the non-reduced form (S
1
) for subsequent reduction by suitable sulfur dye reducing agent(s) in the application bath, or they may be provided to the bath as pre-reduced sulfur dyes (S
2
), in particular as liquid concentrated compositions, which are frequently aqueous alkaline solutions containing the alkali soluble leuco sulfur dye thiolate, or as dry compositions. As pre-reduced sulfur dyes (S
2
) there are more specifically meant pre-reduced sulfur dyes which are in a partially reduced form as is sufficient in order to be readily soluble in alkaline solutions and which may, if desired, be further reduced for application, and further or fully reduced sulfur dyes which are readily soluble in alkaline solutions and are directly usable for application. Both are embraced by the term leuco sulfur dyes. Solubilized sulfur dyes (Bunte salts) (S
3
) may also be employed according to the invention.
Exemplary sulfur dyes (S) which may be utilized in accordance with the process of the invention include but are not necessarily limited to the following (“C.I.” stands for “Colour Index”):
C.I. Sulfur Yellow 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 16, 20 and 23, C.I. Leuco Sulfur Yellow 2, 4, 7, 9, 12, 15, 17, 18, 21, 22 and 23 and C.I. Solubilized Sulfur Yellow 2, 4, 5, 19, 20 and 23;
C.I. Sulfur Orange 1, 2, 3, 4, 5, 6, 7 and 8, C.I. Leuco Sulfur Orange 1, 3, 5 and 9 and C.I. Solubilized Sulfur Orange 1, 3, 5, 6, 7 and 8;
C.I. Sulfur Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12 and 13, C.I. Leuco Sulfur Red 1, 4, 5, 6, 11 and 14 and C.I. Solubilized Sulfur Red 3, 6, 7, 11 and 13;
C.I. Sulfur Violet 1, 2, 3, 4 and 5, C.I. Leuco Sulfur Violet 1 and 3 and C.I. Solubilized Sulfur Violet 1;
C.I. Sulfur Blue 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19, C.I. Leuco Sulfur Blue 1, 2, 3, 5, 7, 8, 9, 11, 13, 15 and 20 and C.I. Solubilized Sulfur Blue 1, 2, 4, 5, 6, 7, 10, 11, 13, and 15;
C.I. Sulfur Green 1, 2, 3, 4, 5, 6, 7, 8:1, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32 and 33, C.I. Leuco Sulfur Green 1, 2, 3, 4, 7, 11, 16 30, 34, 35, 36, and 37 and C.I. Solubilized Sulfur Green 1, 2, 3, 6, 7, 9, 19, 26 and 27;
C.I. Sulfur Brown 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 14:1, 15, 15:1, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 53:1, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 84, 85, 87, 88, 89, 90, 91, 93 and 94, C.I. Leuco Sulfur Brown 1, 3, 4, 5, 8, 10, 11, 12, 14, 15, 21, 23, 26, 31, 37, 43, 44, 81, 82, 86, 87, 90, 91, 92, 93, 94, 95 and 96 and C.I. Solubilized Sulfur Brown 1, 4, 5, 8, 10, 11, 12, 14, 15, 16, 21, 26, 28, 31, 51, 52, 56, 60, 75, 80 and 83;
C.I. Sulfur Black 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 and 17,
C.I. Leuco Sulfur Black 1, 2, 6, 9, 10, 11 and 18 C.I. Solubilized Sulfur Black 1, 2, 5, 7 and 11.
A more complete and particularized listing of the dyestuffs mentioned above may be found in the Colour Index, 3rd. Ed., published by the Society of Dyers and Colourists (London, GB), as well as in the supplementary volumes published thereto.
The sulfur dyes (S) may be employed in a form as commercially available; the soluble reduced or pre-reduced, i.e. leuco sulfur dyes (S
2
), may in particular be employed in a form as commercially available, and which may contain some residual excess reducing agent
Carlough Mark S.
Hipp J. Michael
Sherrill William T.
Stahala Peter
Clariant Finance (BVI) Limited
Einsmann Margaret
Hanf Scott E.
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