Salt free dyeing of cellulosic fibers with anionic dyes

Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system

Reexamination Certificate

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C544S204000, C544S207000, C544S208000, C544S210000, C544S211000, C544S212000, C524S100000, C008S537000, C008S543000, C008S544000

Reexamination Certificate

active

06350872

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to compounds and processes for using the same to improve the dyeability of textile fibers and fibrous assemblies. More particularly, the present invention relates to quaternary ammonium compounds and processes for using the same to dye cellulosic fibers and fibrous assemblies with anionic dyes without the use of salt.
BACKGROUND OF THE INVENTION
Many dyestuffs are rendered water-soluble by the incorporation of anionic groups into the dye molecule. However, the surface of cellulosic substrates is also negatively charged, and thus tends to repel anionic dyestuffs. Therefore, prior to the instant invention, virtually all dyes classified as anionic required some level of salt to speed the dyeing process.
Specifically, in a typical anionic dyeing process, the dye and the cellulosic substrate (cotton, rayon, etc.) are placed into a hot water bath, in which the cellulosic substrate swells. Salt is then added to the water to “salt” the dye out of solution and into the fiber. Indeed, conventional anionic dyeing processes for cellulosic fibers can employ significant amounts of salt, such as sodium chloride or sodium sulfate, as a dyebath exhausting agent. However, use of salts in dyeing can result in environmental problems relating to disposal of the exhausted dyebath.
Fiber reactive quaternary ammonium compounds have been used in conjunction with anionic dyes to increase various dyeing characteristics (such as color, color fastness, and the like). Salt free dyeing of cellulosic substrates has also been reported. For example, U.S. Pat. Nos. 5,330,541 and 5,489,313, both to Hall et al., report the use of a quaternary ammonium pretreat to eliminate salt in anionic dyeing of cellulose. In particular, the Hall et al.patents are directed to the use of an epoxy propyl trimethyl ammonium chloride pretreatment to eliminate salt in dyeing.
While these and other compounds can be useful in the dyeing of cellulosic fibrous assemblies, commercial use of such compounds has been limited. Such compounds can lack sufficient substantivity for the cellulose to provide subsequent dye color yield values comparable to those achieved when dyeing in the presence of salt. In addition, such processes can exhibit limited adaptability to various dye processes, and in particular to exhaustion or long liquor processes using conventional liquor ratios. In addition, it can be difficult to uniformly apply these compounds and/or control increased dyestuff rate-of-strike. Still further, these reagents can react sluggishly so that fixation of the compounds to a fabric must be conducted under relatively drastic conditions, for example, at elevated temperatures, high pH, and/or lengthy reaction times.
SUMMARY OF THE INVENTION
The present invention provides processes for dyeing textile fibrous assemblies having notable ecological advantages over conventional dyeing processes requiring the addition of salt to the dye-bath. Specifically, the present invention provides processes for improving the dyeability of textile fibrous assemblies containing cellulosic fibers without requiring a salt to drive the dyestuff into the cellulosic fiber. As a result, the expense, handling difficulties and disposal problems associated with salt can be eliminated. In addition, the dyes can exhaust completely to the fibrous assemblies and provide desirable deeper shades, thus maximizing dye utilization and allowing significant reductions in dyestuff usage. Further, the resulting textiles can be uniformly dyed and possess good colorfastness, thereby eliminating or minimizing the need for a fixative. Still further, the processes of the invention can be used with a variety of dyeing techniques, such as pad batch and exhaustion processes. Indeed, in contrast to prior salt-free dyeing techniques, the present invention allows the use of conventional liquor ratios in an exhaustion process. Thus the processes of the invention can also provide significant advantages in efficiency and cost as compared to conventional dyeing processes.
In the invention, fibrous assemblies comprising cellulosic fibers are treated with an aqueous composition comprising a novel highly substantive fiber reactive cationic compound of the formula (I) below:
wherein:
R
1
, R
2
, and R
3
each are independently selected from the group consisting of C
1
to C
20
alkyl, C
5
-C
12
cycloalkyl, and C
6
-C
10
aryl, each of which is optionally substituted by 1-3 halogen, amino, hydroxyl, C
1
-C
4
alkoxy or C
1
-C
4
alkyl; or R
1
and R
2
, together with N, form a 5, 6 or 7 membered heterocyclic ring, such as pyrrolidine, pyrrolidone, piperidine, morpholine, piperazine and the like, or form a 5, 6, or 7 membered heterocyclic aromatic ring such as pyridine, pyrrole, pyrimidine, imidazole, nicotinamide and the like, wherein each of said heterocyclic ring or heterocyclic aromatic ring may be optionally substituted by one or more hydroxyl, amine, amide, carboxyl, carbonyl or C
1
-C
4
alkyl; or R
1
, R
2
, and R
3
, together with N, form a bridged heterocyclic ring, such as quinuclidine, 1,4-diazabicyclo[2.2.2]octane (DABCO), and the like, optionally substituted by one or more hydroxyl, amine, amide, carboxyl, carbonyl or C
1
-C
4
alkyl;
R
4
is hydrogen or C
1
-C
4
alkyl;
X is C
1
-C
10
alkylene, preferably substituted by hydroxyl;
R
5
is a 5 or 6 membered heterocyclic aromatic ring, preferably containing one or more nitrogen atoms, and having at least one reactive substituent capable of bonding with hydroxyl and amine groups;
Y is —NH—, —NR
4
— or —S—;
Z is C
6
-C
10
aryl, C
5
-C
12
cycloalkyl, or C
2
-C
10
alkylene; and
An
(−)
is an anion.
Preferably, each R
1
, R
2
, and R
3
is C
1
to C
4
alkyl; R
4
is hydrogen; X is of the formula:
wherein X
1
is C
1
-C
10
-alkylene; R
5
is a triazine ring substituted with at least one halogen; each Y is —NH— or —NCH
3
—; and Z is benzene. In an especially preferred embodiment of the invention, the compound has the formula
The cellulosic substrate is also treated with a suitable alkaline agent, such as sodium carbonate, under conditions sufficient to allow the pretreatment compound to covalently react with the cellulosic fibers of the fabric. The cationic reactant and alkaline agent can be applied to the fabric simultaneously or sequentially.
The fabric can then be dyed using a variety of anionic dyes, such as fiber reactive dyes, direct dyes, sulfur dyes, and vat dyes, using various dyeing techniques. Because the compounds of the invention can exhibit pronounced reactivity with hydroxyl groups of the cellulosic fibers, the compounds of the present invention can be applied under mild conditions. Accordingly, the process can be carried out at lower temperatures, lower pH values, and/or shorter reaction times than that required for prior fixing agents, such as those noted above which include an epoxy group as the reactive radical. In addition, such pretreated fibrous assemblies can be dyed using an exhaustion process with conventional process conditions. Further, the dyestuffs are substantially fully exhausted onto the fibrous assembly, resulting in a dyed material having good, uniform color and colorfastness. The remaining dye-bath effluent is substantially colorless (water-white) and free from undesirable salts, contaminants and the like.
Compounds of Formula (I) above are also provided in another aspect of the invention. The compounds of the invention can exhibit improved substantivity for cellulosic fibers as compared to traditional quaternary amines, in particular low molecular weight quaternary amines such as epoxy propyl trimethyl ammonium chloride. Due to its high substantivity, the compound can be applied to the cellulosic fibers under so-called long-liquor conditions, and the treated cellulosic fibers can subsequently be dyed with, for example, reactive dyes having water solubilizing groups such as sulphonate groups, without salt additions to the dyebath. In addition, the compounds allow use of a wider range of commercial process equipment to pretreat the fiber, wh

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