EP0699797A2 - Process for dyeing by the exhaust method, with sulphur dyes - Google Patents

Abstract

A process for the extn. dyeing of cellulose fibre materials with sulphide dyes comprises: (a) contacting the material with an aq. dye liq. contg.: (S) sulphide dye(s) in at least partly soluble form (Sa), and (R) sulphide-free reducing agent(s) in a closed vessel under a reduced-oxygen atmos., and then (b) oxidising the dye. Also claimed is a concentrated leuco dye prepn. contg.: (S2) a leuco-sulphide dye, (R) a sulphide-free reducing agent, and (C) a chelating agent.

Description

The invention relates to exhaust dyeing processes which are suitable for dyeing cellulose-containing fiber material.

As has been known for many years, sulfur dyes are advantageously used for dyeing and / or printing cellulosic fiber material and / or cellulosic textile fiber mixtures. In conventional dyeing processes, the sulfur dyes are in a water-soluble (pre) reduced form, i.e. applied in leuco form and are applied to the cellulose fiber in a variety of methods and then oxidized in order to achieve a color development and / or a level of authenticity of the colored cellulose substrate.

Reducing agents which are usually used for the application of sulfur dyes are in particular: sodium hydrogen sulfide, sodium sulfide and sodium polysulfides. For example, Japanese Kokai 60-17185 and 60-119285 and US Pat. No. 4,082,502 describe dyeing processes in which sulfur dyes are reduced with sulfide, the dyeing being carried out in closed apparatus, specifically in Japanese Kokai 60 -17185 and 60-119285 with the addition of nitrogen or an inert gas and in US Pat. No. 4,802,502 under HT conditions with the addition of steam. Other chemical reducing agents that do not contain sulfide ions (ie, "sulfide-free" reducing agents) known to reduce sulfur dyes include: sodium borohydride, formamidine sulfinic acid, glyceraldehyde, hydroxyacetone, hydroxylamine sulfate, lignin sulfonates, sodium formaldehyde sulfoxylate, sodium hydrosulfite, thioglycolic acid, and various reducing agents. Although effective, these reducing agents are known to have certain disadvantages. For example, although sulfides are known to be effective reducing agents that are fairly insensitive to atmospheric oxidation, they can be of concern with safety, malodour, and waste disposal. On the other hand, the use of sulfide-free reducing agents offers the advantage that they do not cause the same environmental concerns and appropriate waste disposal as sulfide-containing reducing agents, but their applicability is largely limited because of the instability of their corresponding reducing liquors against oxidation in the presence of atmospheric oxygen. This is particularly the case for sulfur dyes other than black sulfur dyes. In addition, when using special dyeing machines, especially reel runners and jet dyeing machines, in which, due to the manner in which the textile material to be dyed is carried, which entrains the adhering air (and consequently oxygen), the use of such sulfide-free reducing agents is mostly unsuccessful except to a certain extent if the dye used is a black sulfur dye .

That is why it is The object of the invention to provide an improved process for dyeing cellulose fiber materials and cellulose mixed fiber materials, in which one or more sulfur dyes are used and one or more sulfide-free reducing agents are used, especially when using non-black sulfur dyes.

The invention thus relates to a process for dyeing cellulose-containing fiber material with a sulfur dye by the exhaust process, which is characterized in that the fiber material in an enclosed vessel and under an atmosphere with reduced oxygen content with an aqueous dye liquor containing at least one sulfur dye (p ) in at least partially soluble form (S _A ) and contains at least one sulfide-free reducing agent (R), brings them into contact and then oxidizes them.

An atmosphere with a reduced oxygen content is here an atmosphere in which the oxygen content is lower than that of normal air, which contains about 21% by volume of oxygen. The atmosphere with reduced oxygen content advantageously contains no more than 12 volume% oxygen, preferably no more than 10 volume%.

The cellulose-containing fiber material means a substrate which contains cellulose fibers and may optionally contain fibers other than cellulose fibers which can be mixed with the cellulose fibers, and is preferably textile material. Other fibers than cellulose fibers are semisynthetic and fully synthetic polymeric fiber materials, in particular cellulose acetates, polyamides (also aramids), polyesters, polyolefins, polyacrylonitriles and also others which are known in the art as being suitable for forming fiber mixtures with cellulose fibers. The fibers can be in any customary processing form, in particular as loose fibers, threads, yarns or semi-finished products, primarily in the form of twisted yarn or fiber strands or docks, yarn spools, knitted fabrics or fabrics, or also finished products such as clothing. The fiber material, in particular the textile material, advantageously contains at least 15% by weight of cellulose fibers, primarily at least 40% by weight, ie 40-100% by weight of cellulose fibers.

Suitable sulfur dyes (S) which can be used according to the invention are those which are used either in non-reduced form (S₁) for subsequent reduction by sulfide-free reducing agents for sulfur dyes in the dyebath, or (pre) reduced sulfur dyes (S₂) in particular as liquid concentrated preparations, which are mostly aqueous alkaline solutions containing alkali-soluble leucosulfur dye thiolates, or as dry dye preparations. (Pre) reduced sulfur dyes (S₂) are in particular (pre) reduced sulfur dyes (S₂ '), which are present in a partially reduced form, which is sufficient for them to be readily soluble in alkaline solution and, if desired, to be further reduced for application, as well as further or fully reduced sulfur dyes (S₂ ''), which are easily soluble in alkaline solutions and can be used directly for application. Both (S₂ ') and (S₂'') are included in the term "leuco sulfur dyes". Thiosulfonate sulfur dyes (colored salts) (S₃) can also be used according to the invention. The dyes (S _A ), which are at least partially dissolved in the alkaline dye liquor, are alkali-soluble forms of sulfur dyes, such as colored salts (S₃), pre-reduced sulfur dyes (S₂ '), further reduced sulfur dyes (S₂'') or alkali-soluble thionation products (S₁''). If the dye is in insoluble form (S₁ '), a soluble form is formed in the (R) -containing dye bath; in the dyebath the dissolved dyes (S _A ) are reduced, if necessary or desired, to a reduced form (S _A ') which is suitable for dyeing and which in particular (S₂) and at least partially reduced forms of (S₃), ie (S₃') , includes.

Suitable sulfur dyes (S) which can be used in the process according to the invention are, for example, those of the following "Color Index" names ("CI" stands for "Color Index"):
CI Sulfur Yellow 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 16, 20 and 23, CI Leuco Sulfur Yellow 2, 4, 7, 9, 12, 15 , 17, 18, 21, 22 and 23 and CI Solubilized Sulfur Yellow 2, 4, 5, 19, 20 and 23;
CI Sulfur Orange 1, 2, 3, 4, 5, 6, 7 and 8, CI Leuco Sulfur Orange 1, 3, 5 and 9 and CI Solubilized Sulfur Orange 1, 3, 5, 6, 7 and 8;
CI Sulfur Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12 and 13, CI Leuco Sulfur Red 1, 4, 5, 6, 11 and 14 and CI Solubilized Sulfur Red 3, 6 , 7, 11 and 13;
CI Sulfur Violet 1, 2, 3, 4 and 5, CI Leuco Sulfur Violet 1 and 3 and CI Solubilized Sulfur Violet 1;
CI Sulfur Blue 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19, CI Leuco Sulfur Blue 1, 2, 3 , 5, 7, 8, 9, 11, 13, 15 and 20 and CI Solubilized Sulfur Blue 1, 2, 4, 5, 6, 7, 10, 11, 13, and 15;
CI 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, CI Leuco Sulfur Green 1, 2, 3, 4, 7, 11, 16 30, 34, 35, 36, and 37 and CI Solubilized Sulfur Green 1, 2, 3, 6, 7, 9, 19, 26 and 27;
CI 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, CI 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 CI 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;
CI Sulfur Black 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 and 17, CI Leuco Sulfur Black 1, 2, 6, 9, 10 , 11 and 18 CI Solubilized Sulfur Black 1, 2, 5, 7 and 11.

A more complete and detailed list of the above dyes can be found in the Color Index, 3rd edition (Society of Dyers and Colorists, London, GB) and in the supplementary works.

Particular nuances of sulfur dyes for which the process according to the invention is particularly suitable include shades of yellow, orange, red, violet, blue, green and brown and combinations thereof, blue (also navy blue) dyes being particularly preferred.

According to the invention, a sulfur-free reducing agent (R) is used in the dye liquor; it can be used to reduce a sulfur dye (S₁) and (S₃) or a pre-reduced dye (S₂ ') present in the dyeing liquor or to obtain the reduced state (leuco form) of a (pre) reduced dye (S₂).

The dyes (S) can be used in a commercially available form: the soluble, reduced or pre-reduced dyes, ie leucosulfur dyes (S₂), can be used in particular in commercially available forms, which may contain other reducing agents from their production and, if necessary, especially in liquid form or if desired may contain additional reducing agent to stabilize the reduced form against the oxidizing influence of the ambient air.

It is advantageous, especially for ecological reasons, that the sulfide content of (S) be as low as possible, preferably <3%, particularly preferably <0.1%, based on the dry weight of the dye.

Suitable sulfide-free reducing agents (R) are those mentioned above, among which the organic ones are preferred, in particular reducing sugars, hydroxyacetone, glyceraldehyde, sodium formaldehyde sulfoxylate, formamidine sulfinic acid and thioglycolic acid. (R) is particularly preferred a reducing agent which contains neither nitrogen atoms nor sulfur atoms, in particular a reducing sugar, hydroxyacetone or glyceraldehyde, among which reducing sugars are most preferred.

Particular advantages associated with the use of the sulfide-free reducing agents (R) according to the invention, in particular the organic reducing agents, and in particular the preferred, especially the reducing sugars, for reducing the sulfur dyes include: a safer chemical system because of the reduced likelihood of developing dangerous substances Hydrogen sulfide gas when the dye liquor is acidified compared to sulfide reducing agent; reduced environmental concerns with regard to waste disposal, since the sulfide-free reducing agents (R), especially the organic ones, and especially the preferred ones, especially the reducing sugars, are readily biodegradable, and the elimination of the formation of malodors from the aqueous sulfur dye liquor.

A preferred group of sulfide-free reducing agents thus contains reducing sugars, which are particularly effective in the process according to the invention for reducing sulfur dyes (S₁) and also (S₃) or (S₂ ') to their reduced forms, and consequently particularly suitable for dyeing cellulose fiber material or cellulose fiber mixtures are. Effective reducing sugars are meant those that are capable of reducing Fehling's solution and include a variety of carbohydrates, especially mono- and oligosaccharides, some of which are already known in the art. Usable reducing sugars are in particular those which are referred to as aldo- and / or keto-triose, -tetrose, -pentose and -hexose, but are not limited thereto. Examples of such reducing sugars are fructose, Galactose, glucose, mannose, maltose and lactose; other reducing sugars which are able to reduce the Fehling's solution and consequently also a sulfur dye to its (pre) reduced form can also be used.

Sodium hydrosulfite, also known as sodium dithionite, is known in the art as a vat dye reductant (Vat Dyes, as defined in the Color Index), but the use thereof in conventional sulfur dye liquors leads to the observed difficulties in controlling the degree of reduction of the sulfur dye so that these Method does not find a general acceptance in the professional world. An over-reduction of some sulfur dyes leads to the destruction of the dye chromophore, while an under-reduction makes the reduced dye bath unstable against air oxidation, which can lead to "bronzed" dyeings; both of these disadvantages lead to nuance variations and deviations that are observed in the ultimately colored product compared to the expected pattern. These disadvantages are eliminated according to the invention.

Thiourea dioxide, also called formamidine sulfinic acid, is also a useful reducing agent for vat dyes known in the art, but likewise there is no general decrease in the use for the application of sulfur dyes, because of the same difficulties mentioned above for sodium hydrosulfite and the like. the uneven reduction of sulfur dyes. These disadvantages are eliminated according to the invention.

The dyeing is expediently carried out under alkaline conditions, advantageously at pH values ≧ 10, in particular in the range from 10 to 14, preferably 10.5 to 13, particularly preferably 11 to 12.5. The liquor length can fluctuate in any range as is suitable for dyeing processes in closed vessels, in particular in reel runners or jet dyeing machines, and is advantageously in the range from 1: 4 to 1:20, preferably 1: 6 to 1:12, particularly preferably 1: 8 to 1:10. The concentration of (R) can be selected depending on the type, amount and concentration of the dye used and the type of (R) and can also vary depending on the type of substrate and the particular dyeing method. The reducing agent (R) is expediently used in an amount which is suitable for reducing a sulfur dye, in particular (S₁) and also (S₃) or (S₂ '), in a suitable manner to its reduced form under the dyeing conditions used and / or to obtain the reduced state of a (pre) reduced sulfur dye, in particular (S₂). The concentration of the reducing agent (R) is advantageously in the range from 0.5 to 15% by weight, preferably 1 to 10% by weight, particularly preferably 2 to 6% by weight, in particular 3 to 5% by weight, based on the dry weight of the substrate. The dyeing temperature can also vary depending on the dyeing method and the dyeing apparatus and is advantageously in the range from 35 to 130 ° C., primarily 45 to 105 ° C., preferably 60 to 100 ° C.

Concentrations of 1 to 10 g / l reducing sugar, e.g. Glucose is preferred in order to achieve a reduction at dyeing temperatures in the range from 70 to 130 ° C., the sulfur dye being present in such a concentration as is required by the dyeing conditions and the desired depth and shade of dyeing.

For aqueous dyeing liquors in which sodium hydrosulfite is used as a reducing agent, the sodium hydrosulfite is advantageously used in concentrations of 1 to 4 g / l in order to effectively reduce a sulfur dye (S₁) and (S₃) or (S₂ '). Concentrations higher or lower than these can be considered, depending on the aqueous sulfur dye liquor in which the sodium hydrosulfite is used. The dyeing temperatures can generally correspond to those used for sulfide-reduced sulfur dye liquors and are primarily above 38 ° C., with good results in the temperature range from 49 to 105 ° C., preferably 60 to 100 ° C., in particular 70 to 93 ° C. , can be achieved.

For aqueous dyeing liquors in which thiourea dioxide is used as a reducing agent, the concentration of thiourea dioxide is preferably in the range from 1 to 4 g / l in order to effectively reduce a sulfur dye (S₁) and (S₃) or (S₂ '). Higher or lower concentrations can also be considered, depending on the aqueous sulfur dye liquor used in which the thiourea dioxide is used. The dyebath temperatures can generally correspond to those used for sulfide-reduced sulfur dye liquors and are primarily in the range above 38 ° C, with good results in the temperature range from 49 to 105 ° C, preferably 60 to 100 ° C, in particular 70 to 93 ° C, can be achieved.

For aqueous dye liquors in which thioglycolic acid, also known as mercaptoacetic acid, is used as a reducing agent, the thioglycolic acid is advantageously used in concentrations of 1 to 5 g / l in order to effectively reduce the sulfur dye (S₁) or (S₃) or (S₂ ') to achieve. Concentrations lower or higher than this can be considered depending on the aqueous sulfur dye liquor in which the thioglycolic acid is used. The dye liquor temperatures can generally correspond to those used for sulfide-reduced sulfur dye fleets and are predominantly above 38 ° C., good results in the temperature range from 49 to 105 ° C., preferably 60 to 100 ° C., in particular 70 to 93 ° C. can be achieved.

Other sulfide-free reducing agents which are known to be useful for the reduction of sulfur dyes can also be used according to the invention. An additional advantage of the process according to the invention is that less reducing agent can be used than is otherwise required.

The suitable or preferred amount of (R) depends essentially on the type and amount of (S) and is, for example, in the range from 0.5 to 10 g / l, based on the volume of the dyeing liquor. Even if the dye (S) is used in (pre) reduced form (S₂), a certain amount of (R) must be present in the liquor, preferably 0.5 to 5 g / l, also depending on the type of substrate and Amount of trapped air that is carried through and in the substrate and to maintain unoxidized conditions during dyeing. The amount of reducing agent (R), which may optionally be in a commercial form of (S₂), can also be included in the calculation. The process can be used for any dyeing process in which dyeing is carried out using sulfur dyes using sulfide-free reducing agents or, if the dye already contains a reducing agent (R), even in the absence of added reducing agent. For example, in the case of a non-reduced form of a sulfur dye (S₁) or (S₃) a sulfide-free reducing agent (R) is used, while in the case of a (pre) reduced form of a sulfur dye (S₂), as indicated above, the presence of an added reducing agent (R ) is not absolutely necessary. These processes are advantageously carried out in aqueous alkaline dye liquors.

According to a particular embodiment of the invention, the reducing agent (R) is used in the presence of a chelating agent (C), in particular an exhaustively carboxymethylated derivative of a low amino compound, such as ethylenediaminetetraacetic acid or diethylenetriaminepentaacetic acid or nitrilotriacetic acid, preferably in alkali metal salt form, for example in a concentration in the range from 0 , 1 to 2 wt .-% (C) based on the dry weight of the substrate, for example in the range of 1 to 20 wt .-% (C) based on the weight of (R). If a leucosulfur dye (S₂) is used in the form of a concentrated (R) -containing preparation, a chelating agent (C) can also be contained in such a preparation, which is preferably alkaline, for example in a concentration of 3 to 40 parts by weight (C) per 100 parts by weight (S₂). In these concentrated preparations, the (S₂) content is preferably ≧ 8.5% by weight, mainly ≧ 12% by weight; they can be aqueous or dry and are preferably alkaline.

According to a particular embodiment of the invention, the first stage of the process according to the invention is characterized in that the cellulose fiber is brought into contact with a sulfur dye dyeing liquor in the presence of a sulfide-free reducing agent (R) and in the presence of an inert gas, the inert gas to form an inert gas atmosphere or / and for flushing out the atmosphere that is in contact with the dye liquor. During the extraction phase, the inert gas is used to maintain the inert gas atmosphere above or in contact with the dye liquor, so that an inert atmosphere is obtained within the dyeing apparatus. According to another embodiment, the first stage is carried out under vacuum or reduced pressure. According to a further process variant, the first stage of the dyeing process is carried out after or after purging the atmosphere with steam and introducing another inert gas, which is then used to maintain the inert gas atmosphere within the dyeing apparatus. The process described here is particularly advantageous in reel runners and nozzle dyeing machines.

Inert gases which are suitable for the process according to the invention are in particular one or more of the following: noble gases (preferably argon), nitrogen or water vapor and, if appropriate, carbon dioxide. Inert gases are understood in particular to mean those which do not tend to react, in particular to oxidize, with the reduced sulfur dye in the dyeing liquor which is contained in the dyeing apparatus, and which are capable of reducing the amount of oxygen which is present in the Vessel captured atmosphere is included to effectively degrade to the values given above. The inert gas is advantageously nitrogen, a noble gas or carbon dioxide, preferably nitrogen or a noble gas, particularly preferably nitrogen.

According to one embodiment of the method according to the invention, the substrate to be colored is loaded in a conventional coloring apparatus, in which the internal volume which is not filled with liquid, ie the "trapped atmosphere" or simply "atmosphere", is first flushed out with an inert gas the amount of oxygen contained in the trapped atmosphere to not more than 12% by volume, preferably not more than 10% by volume, especially not more than 7% by volume belittling. A reduction to a total absence of oxygen is within the scope of the invention, but is unnecessary and expensive to achieve. The oxygen content is preferably in the range from 0.5 to 7.0% by volume, particularly preferably in the range from 1.0 to 5.0% by volume. The indicated reduced oxygen contents are advantageously obtained during the entire first stage of the dyeing process, ie during the extraction of the at least partially reduced and soluble dye (S _A ').

Two categories of dyeing machines in which the method set out here is advantageously used are nozzle dyeing machines and reel skid dyeing machines. The reason why these devices are used with advantage is because of the way in which the substrate to be colored is handled: in both devices the substrate is transported mechanically through the dyeing liquor and then through the captured atmosphere inside the device and then back into and by the dye liquor; and this process continues until a sufficient color is obtained. This repeated mechanical conveyance through the captured atmosphere and then through the dye liquor, etc. is a cause why the gas content of the captured atmosphere is introduced into the liquor by carrying gas trapped in the substrate. This phenomenon will be understood by those skilled in the art and is a major means by which entrained atmospheric oxygen can be introduced into the aqueous sulfur dye liquor composition. While this is not necessarily a disadvantage if the sulfur dye dyeing liquor is one in which sulfide is used as the reducing agent, it has been found that the opposite is the case when a sulfide-free reducing agent is used in the presence of air with undiminished oxygen content.

According to a further embodiment, water vapor can also be used as a rinsing agent. The vapor may be unsaturated, saturated or supersaturated, but is preferably unsaturated or saturated vapor, and the vapor pressure should be sufficient to remove and purge the trapped atmosphere from the dyeing machine. After rinsing the atmosphere within the dyeing apparatus at a temperature below the boiling point, the vapor generally cools and condenses so that vacuum or reduced pressure (ie less than one atmosphere, ie <0.98 bar) conditions within the dyeing apparatus arise which conditions may be desired or undesirable. If such a reduced pressure is compatible with the equipment used and if a reduced pressure can be obtained, no further measures are required to achieve the desired reduced To reach oxygen level. However, if such reduced pressures are undesirable, after steam condensation within the dyeing apparatus, an amount of inert gas may be introduced into the dyeing apparatus to form an inert gas atmosphere therein.

According to another further embodiment of the invention, the dyeing machine can be equipped with a vacuum suction device, e.g. a vacuum pump, are connected, whereby the captured atmosphere of the dyeing vessel is conducted under reduced pressure or vacuum. The use of such a vacuum apparatus can offer the advantages that a regular flow of inert gas can be maintained from the gas feed through the internal volume of the vessel not occupied by liquid and also through the vacuum suction apparatus. Since this method requires a regular sweeping of inert gas through the dyeing machine, it offers the further advantage that any atmospheric oxygen that can penetrate into the interior of the apparatus, if the apparatus is not properly sealed, is also extracted and is not retained. The operating pressure of such a vacuum apparatus can be at any pressure which is suitable for achieving the above effects, preferably at a pressure which is slightly below the inlet pressure of the inert gas which is fed into the dyeing apparatus.

According to yet another embodiment, the vacuum apparatus can be used alone, without simultaneous feeding in of inert gas, etc. so that the inert gas previously introduced into the dyeing apparatus is slowly extracted and a reduced pressure is created in the interior of the dyeing apparatus which is not occupied by liquid.

If desired, further dyeing aids can be used in the process according to the invention, in particular wetting agents, defoamers, deaerating agents, water-soluble mineral salts (preferably sodium sulfate or chloride) and - to adjust the pH to the desired value - bases (e.g. alkali metal hydroxides or carbonates) or acids ( especially low molecular weight aliphatic carboxylic acids, for example with 2 to 4 carbon atoms, preferably acetic acid), as is customary per se in dyeings. The concentration of soluble mineral salts added (especially as an extractant) can be kept at a very low level, e.g. <30 g / l (0 to 30 g / l) based on the dye liquor.

Preferably, the first stage (exhaust phase) of the dyeing process is completed with a rinsing out of the liquor, which is advantageously carried out as long as the atmosphere's oxygen content has decreased is still preserved. It is particularly preferred to rinse with water until the rinsing liquor is clear.

After the pull-out phase has ended, the treated substrates are subjected to an oxidative treatment in a second phase, in particular using an oxidizing agent (B). In this second stage, which is advantageously carried out under acidic conditions, the dye on the substrate is oxidized, in particular in order to achieve color development and a fastness level.

Any (oxidizing agents) which can usually be used per se for sulfur dyes, e.g. a gaseous form of oxygen (oxygen, ozone, air or air enriched with oxygen and / or ozone or a mixture of inert gas and oxygen and / or ozone), hydrogen peroxide or preferably an oxidizing salt, e.g. Sodium or potassium perborate, percarbonate, bichromate, chlorate, iodate or bromate, the latter preferably in the presence of a suitable activator, e.g. Alkali metal metavanadate; among them, the bromate is particularly preferred, especially in the presence of sodium or potassium metavanadate.

For the second stage, i.e. for the oxidative stage, the atmosphere can be relieved of the reduced oxygen level of the first stage or set to a higher oxygen level, advantageously> 12% by volume, preferably> 15% by volume, particularly preferably> 18% by volume, e.g. up to 21 vol.% or higher. This is advantageously accomplished by introducing a gaseous form of oxygen as described above, e.g. by relieving a previous vacuum or reduced pressure or by ventilating the highly inert atmosphere of the first stage or by introducing a gaseous form of oxygen at excess pressure, e.g. between 0.1 and 2 bar, e.g. if the reducing dye bath is drained and / or if necessary after the above-mentioned rinsing of the liquor. According to a particular embodiment of the invention, the oxygen level is increased before the second stage by introducing air, advantageously at an excess pressure in the range from 0.2 to 1.5 bar, preferably 0.4 to 1 bar. The oxidation with the dissolved oxidizing agent in the presence of this "air cushion" is particularly advantageous and leads to colorations of optimal yield and fastness.

The oxidation bath suitably contains an effective amount of oxidizing agent (B), which is preferably an oxidizing salt (B₁), advantageously in the range from 0.2 to 12 g / l, preferably 0.5 to 5 g / l, particularly preferably 1 to 2 g / l, based on the liquor volume. The liquor ratio is advantageously in the same range as in the first stage. The oxidation is advantageously carried out with mild heating, preferably in the temperature range from 40 to 75 ° C., particularly preferably 49 to 71 ° C., and at a pH in the range from 4 to 6, preferably 4.5 to 5.5.

After the second stage has been completed, the oxidized material can be rinsed and neutralized, e.g. with sodium carbonate, as is customary after a sulfur dye dyeing, and can be finished in a conventional manner, e.g. by rinsing, drying and / or, if desired, finishing in a suitable manner with conventional finishing agents.

Very level, clear dyeings of high yield and depth and excellent fastness properties, e.g. Light fastness, wet fastness, especially wash fastness and fastness to staining).

• a) das Wegfallen einer unerwünschten Oxydation des reduzierten Schwefelfarbstoffes im Färbebad welche auch als vorzeitige Farbstoffoxydation bezeichnet wird, was zu einer effizienteren und reproduzierbareren Führung des Färbeverfahrens führt, da das Reduktionsbad leichter zu kontrollieren ist, und weniger Bronzierung des Fabstoffes vorkommt;
• b) unter den Färbebedingungen mit reduziertem Sauerstoffniveau gemäß vorliegender Vorschrift sind kleinere Flottenlängen möglich, welche einen erhöhten Farbstoffauszug ermöglichen und dadurch die allgemeine Leistung des Färbeverfahrens verbessern und die Menge an ausgezogener Flotte herabsetzten, die in den Ablauf zur Aufarbeitung oder Abwasserreinigung geleitet wird;
• c) es sind niedrigere Konzentrationen an Salz bei kleineren Flottenlängen erforderlich, wodurch die Menge an Elektrolyten herabgesetzt wird, die in den Ablauf geleitet wird;
• d) ein niedrigerer Verbrauch an Wasser und Energie, wegen der niedrigeren Flottenlängen die erfindungsgemäß möglich sind, setzt die allgemeinen Kosten des Färbeverfahrens herab und
• e) wegen der Färbebedingungen unter herabgesetztem Sauerstoffniveau, die durch das Verfahren erreicht werden, werden niedrigere Mengen an chemischen Reduktionsmitteln erforderlich, um ein stabiles Reduktionsbad für die Applikation des Schwefelfarbstoffes zu erhalten [d.h. es wird ein stabiles Reduktionsbad unter Verwendung einer kleineren Menge an sulfidfreiem Reduktionsmittel (R) als unter sonst gleichen Bedingungen, aber ohne herabgesetztem Sauerstoffgehalt der Atmosphäre erhalten], wodurch die Menge an chemischen Nebenprodukten, die in den Ablauf geleitet werden, auch herabgesetzt wird, und die Kosten der Farbstoffapplikation und weiter bis zur Abwasseraufarbeitung und Rückgewinnung herabgesetzt werden.

In addition to the use of a sulfide-free reducing agent (R), the process according to the invention leads to many advantages, inter alia

• a) the elimination of undesired oxidation of the reduced sulfur dye in the dye bath, which is also referred to as premature dye oxidation, which leads to a more efficient and reproducible control of the dyeing process, since the reduction bath is easier to control and less bronzing of the dye occurs;
• b) under the dyeing conditions with reduced oxygen level according to the present regulation, smaller liquor lengths are possible, which enable an increased dye extraction and thereby improve the general performance of the dyeing process and reduce the amount of liquor drawn off which is passed into the process for processing or wastewater treatment;
• c) lower concentrations of salt are required with smaller liquor lengths, thereby reducing the amount of electrolytes that are discharged into the drain;
• d) a lower consumption of water and energy, because of the shorter liquor lengths that are possible according to the invention, reduces the general costs of the dyeing process and
• e) because of the dyeing conditions under reduced oxygen level, which are achieved by the process, lower amounts of chemical reducing agents are required in order to obtain a stable reducing bath for the application of the sulfur dye [ie it becomes a stable reducing bath using a smaller amount of sulfide-free reducing agent (R) as obtained under otherwise identical conditions, but without a reduced oxygen content of the atmosphere], which also reduces the amount of chemical by-products which are passed into the outlet, and the costs of the dye application and further down to the waste water treatment and recovery .

In addition to the advantages mentioned, the method according to the invention allows the application of all nuances of sulfur dye to cellulose fiber material and / or cellulose blend fiber material in a closed vessel, such as a nozzle dyeing apparatus or a reel runner, especially of sulfur dyes other than black sulfur dyes. Further advantages, even if not expressly described, will be obvious to the person skilled in the art.

Examples of the method according to the invention are described below. These examples are given to illustrate the invention and are not meant to limit the scope of the invention.

EXAMPLES example 1

A textile substrate is dyed in a nozzle dyeing machine as follows: 500 g of 100% cotton jersey are loaded into a MATHIS Laboratory Jet type JFO dyeing machine. The dyeing machine is then filled with 4500 g of an aqueous solution containing 1 g of ethylenediaminetetraacetic acid sodium salt, 60 g of sodium carbonate, 35 g of glucose and 175 g of sodium sulfate. This liquor is then heated to 49 ° C as the substrate is transported through the machine. During this time to make the atmosphere inert, nitrogen is loaded into the dyeing vessel until an overpressure of 0.6 bar is reached, at which point the vessel is degassed and reloaded with nitrogen. This process is repeated until 5 nitrogen flushes have occurred and then the pressure in the vessel is released so that the coloring is at atmospheric pressure is started. Then an aqueous solution, the 27 g CI Leuco Sulfur Black 1 is introduced into the dyeing vessel via a measuring pump. The dyeing machine is then heated to 93 ° C at a rate of 2.8 ° C / min and held at this temperature for 45 minutes. The jet dyeing machine is then cooled to 71 ° C and rinsed with water in the overflow until the dye liquor is clear. Then 10 g of an aqueous solution containing 1.2 g of sodium bromate and 0.1 g of sodium metavanadate and 5 g of glacial acetic acid are added, and the liquor is then heated to 60 ° C. and kept at this temperature for 10 minutes. The liquor is then drained off and the jet dyeing machine is refilled with water. The fabric is rinsed for 5 minutes, the liquor is then drained and the machine is refilled with water. 5 g of sodium carbonate are added to this liquor and the machine is heated to 88 ° C. and held at this temperature for 10 minutes. A full black color of the textile material with good levelness is obtained.

Example C1

The dyeing process is carried out under identical conditions as described in Example 1, except that the inerting process via nitrogen flushing is omitted; only a medium-deep black color of insufficient levelness was obtained.

Example 2

A textile substrate is dyed in a nozzle dyeing machine as follows: 500 g of 100% cotton jersey are loaded into a MATHIS Laboratory Jet type JFO dyeing machine. The dyeing machine is then filled with 4500 g of an aqueous liquor which contains 1 g of ethylenediaminetetraacetic acid sodium salt, 60 g of sodium carbonate, 35 g of glucose and 175 g of sodium sulfate. This treatment bath is then heated to 49 ° C as the substrate is passed through the machine. In order to make the atmosphere inert, nitrogen is loaded into the staining vessel during this time until an overpressure of 0.6 bar is reached, at which point the vessel is degassed and reloaded with nitrogen. This process is repeated until 5 nitrogen flushes have taken place and the pressure in the vessel is relieved, so that the coloring begins at atmospheric pressure. Then an aqueous solution containing 27 g of CI Leuco Sulfur Blue 20 is added to the dyeing vessel via a measuring pump. The dyeing machine is then at a speed of 2.8 ° C / min. heated to 93 ° C and held at this temperature for 45 minutes. The jet dyeing machine is then cooled to 71 ° C and it is rinsed with water in the overflow until the liquor is clear. Then 10 g an aqueous solution containing 1.2 g of sodium bromate and 0.1 g of sodium metavanadate and 5 g of glacial acetic acid is added, and the liquor is then heated to 60 ° C. and kept at this temperature for 10 minutes. The liquor is then drained off and the jet dyeing machine is refilled with water. The fabric is rinsed for 5 minutes and the machine emptied and refilled with water. 5 g of sodium carbonate are added to this liquor and the machine is then heated to 88 ° C. and held at this temperature for 10 minutes. A deep navy blue coloration of good levelness is obtained.

Example C2

The dyeing process is repeated under identical conditions as described in Example 2, with the difference that the atmospheric inerting process via the nitrogen purges is omitted; a pale blue color of the fabric, of poor levelness, was obtained.

Example 3

A textile substrate is dyed in a nozzle dyeing machine as follows: 500 g of 100% cotton jersey are loaded into a MATHIS Laboratory Jet type JFO dyeing machine. The dyeing machine is then filled with 4500 g of an aqueous solution containing 1 g of ethylenediaminetetraacetic acid sodium salt, 60 g of sodium carbonate, 35 g of glucose and 175 g of sodium sulfate. This liquor is then heated to 49 ° C as the fabric is carried through the machine. During this time, in order to render the atmosphere inert, nitrogen is loaded into the dyeing vessel until an overpressure of 0.6 bar is reached, at which point the vessel is degassed and reloaded with nitrogen. This process is repeated until 5 nitrogen flushes have been carried out and the pressure in the vessel is relieved, so that the coloring is started at atmospheric pressure. Then an aqueous solution containing 27 g of CI Leuco Sulfur Blue 20 is added to the dyeing vessel via a measuring pump. The dyeing machine is then at a speed of 2.8 ° C / min. heated to 93 ° C and held at this temperature for 45 minutes. Then the jet dyeing machine is cooled to 71 ° C and it is rinsed with water in the overflow until the liquor is clear. An air cushion of 0.4 to 1 bar overpressure is introduced and repeated three times in order to increase the oxygen content of the atmosphere inside the vessel to a level> 15% by volume, between 15 and 21% by volume. 10 g of an aqueous solution containing 1.2 g of sodium bromate and 0.1 g of sodium metavanadate and 5 g of glacial acetic acid are then added and the liquor is then heated to 60 ° C and held at this temperature for 10 minutes. The liquor is then drained off and the jet dyeing machine is refilled with water. The fabric is rinsed for 5 minutes and then the liquor is drained and the machine is refilled with water. 5 g of sodium carbonate are added to this liquor and the machine is heated to 88 ° C. and held at this temperature for 10 minutes. A deep navy blue coloration of good levelness is obtained.

Example 4

A textile substrate is dyed in a nozzle dyeing machine as follows: 500 g of 100% cotton interlock jersey are loaded into a MATHIS Laboratory Jet type JFO dyeing machine. The dyeing machine is then filled with 4500 g of an aqueous solution containing 1 g of ethylenediaminetetraacetic acid sodium salt, 15 g of sodium carbonate, 25 g of 50% sodium hydroxide, 17.7 g of glucose and 100 g of sodium sulfate. This liquor is then heated to 49 ° C as the fabric is carried through the machine. During this time, nitrogen is loaded into the coloring vessel until an overpressure of 0.6 bar is reached and then the vessel is degassed and reloaded with nitrogen. This process is repeated until three nitrogen flushes have taken place and the pressure in the vessel is relieved, so that the coloring begins at atmospheric pressure. Then an aqueous solution containing 2.7 g of C.I. Leuco Sulfur Blue 13 is metered into the dyeing machine via a measuring pump. The dyeing machine is then at a speed of 2.8 ° C / min. heated to 93 ° C and held at this temperature for 45 minutes. The jet dyeing machine is then cooled to 71 ° C and it is rinsed with water in the overflow until the liquor is clear. Then 10 g of an aqueous solution containing 1.2 g of sodium bromate and 0.1 g of sodium metavanadate and 5 g of glacial acetic acid are added and the liquor is then heated to 60 ° C. and kept at this temperature for 10 minutes. This liquor is then drained off and the nozzle dyeing machine is refilled with water. The fabric is rinsed for 5 minutes, then the liquor is drained and the machine is refilled with water. 5 g of sodium carbonate are added to this liquor and the machine is heated to 88 ° C. and held at this temperature for 10 minutes. A light blue coloration of the textile substrate with good levelness is obtained.

Example C4

The dyeing process is repeated under identical conditions as described in Example 4, with the difference that the atmospheric inerting process is carried out via the nitrogen purge process is omitted. A pale blue coloration of the substrate with poor levelness was obtained.

Example 5

The dyeing procedure described in Example 4 is repeated, with the difference that instead of 2.7 g of C.I. Leuco Sulfur Blue 13, 16 g C.I. Index Leuco Sulfur Blue 20 are used and the staining is carried out for 45 minutes at 71 ° C instead of 93 ° C. A deep navy blue dyeing of the fabric with good levelness is obtained.

Example 6

2500 g of a 100% cotton knitwear are loaded into a reel runner BENZ Laboratory Winch-Beck type LH dyeing machine. The dyeing machine is then filled with 50 l of an aqueous solution containing 2.6 g of ethylenediaminetetraacetic acid sodium salt, 200 g of an aqueous 25% sodium hydroxide solution, 200 g of glucose and 2250 g of sodium sulfate. This liquor is then heated to 49 ° C as the fabric is fed through the machine. During this time, nitrogen is loaded into the dyeing vessel, blowing it through the liquor and flushing the atmosphere in the vessel and forming an inert gas atmosphere over the liquor. Then an aqueous solution containing 90 g of C.I. Add Solubilized Sulfur Black 2 to the staining jar. The fabric is passed through the liquor for 10 minutes while maintaining the temperature at 49 ° C. The dyeing machine is then heated to 82 ° C and held at this temperature for 20 minutes. The fabric is then rinsed with water in the overflow until the liquor is clear. 50 g of an aqueous solution of 6 g of sodium bromate and 0.5 g of sodium metavanadate and 25 g of glacial acetic acid are added and the liquor is heated to 66 ° C. and kept at this temperature for 50 minutes. This liquor is then drained off and the reel skid dyeing machine is refilled with water. The fabric is rinsed for 5 minutes and the rinse liquor is drained and then the machine is refilled with water. 50 g of sodium carbonate are added to this liquor and the machine is then heated to 71 ° C. and held at this temperature for 10 minutes. A full black color of good levelness is obtained.

Example C6

The dyeing process described in Example 6 is repeated under identical conditions with the Difference that the atmosphere inerting process via the nitrogen purge is omitted; a full black color of the fabric is obtained, which has poor levelness.

Example 7

A jet dyeing machine is loaded with a cotton fabric to be dyed and with enough water to give a liquor ratio of 1:10 and the contents are heated to 49 ° C. At this temperature 0.5 g / l of a 40% aqueous ethylenediaminetetraacetic acid sodium salt solution, 0.5 g / l SODYECO Defoamer DSV (mixture of petroleum derivatives - trademark), 25 g / l sodium sulfate, 5 g / l calcined soda, 5 g / l aqueous 50% sodium hydroxide solution and 5 g / l of a mixture of 94.5% by weight glucose, 5% by weight sodium lignin sulfonate and 0.5% by weight dedusting oil were added to the bath. Such an amount of an aqueous 33% by weight of C.I. Sulfur Black 1 containing suspension metered in, which is sufficient to achieve a concentration of 16% dye, based on the weight of the textile material, and the mixture obtained at a heating rate of 2.75 ° C / min. heated to 71 ° C while the atmosphere above the liquor is purged with nitrogen in the apparatus. The dye bath obtained is then at a rate of 2.75 ° C / min. heated to 93 ° C and held at this temperature for 45 minutes. The dyebath is then cooled to 71 ° C and the contents are rinsed in the overflow with unheated water until the liquor water is clear. The liquor ratio is reset to 1:10 and the liquor is heated to 49 ° C. while the interior of the apparatus is aerated. Now 2 g / l of 56% acetic acid and 2 g / l of an aqueous solution containing 12% sodium bromate and 1% sodium metavanadate are added and the oxidation liquor obtained is heated to 65 ° C. and kept at this temperature for 10 minutes. The liquor is then rinsed out in the overflow and drained and the apparatus is refilled with water, to which 1 g / l of calcined soda are added. The dyed textile material is then rinsed in the resulting liquor at 88 ° C. for 10 minutes. The liquor is then cooled to 71 ° C. and the colored material is unloaded.

In the above examples, ethylenediaminetetraacetic acid sodium salt can be in the form of the commercially available chelating agent SULFALOX 100 (an aqueous alkaline solution of ethylenediaminetetraacetic acid). CI Leuco Sulfur Black 1 can be used in the form of the commercial dye SANDOZOL Black 4G-RDT, CI Leuco Sulfur Blue 13 can be used in the form of the commercial preparation SANDOZOL Blue 2GB-RDT in liquid form, CI Leuco Sulfur Blue 20 can be used in the form of Commercial dye SANDOZOL navy blue GF-RDT can be used in liquid form, CI Solubilized Sulfur Black 2 can be used in the form of the commercial preparation SANDOZOL Black R powder and the mixture of sodium bromate and sodium metavanadate can be used in the form of commercially available aqueous solutions of sodium bromate / sodium metavanadate, such as DYETONE or CHEM -OXY SG.

Claims (18)

Process for the dyeing of cellulose fiber material with a sulfur dye, in which the fiber material is brought into contact with an aqueous dye liquor which contains at least one sulfur dye (S) in at least partially soluble form (S _A ) and at least one sulfide-free reducing agent (R) in a closed one Vessel is brought into contact in an atmosphere with reduced oxygen content and then oxidized. The method according to claim 1, wherein the sulfide-free reducing agent (R) is an organic reducing agent selected from the group consisting of: a reducing sugar, hydroxyacetone, glyceraldehyde, sodium formaldehyde sulfoxylate, formamidine sulfinic acid and thioglycolic acid. A method according to claim 1 or 2, wherein (S) is made of (S₁) a sulfur dye in an oxidized form (S₂) a (pre) reduced sulfur dye (S₃) a thiosulfonic acid sulfur dye (colored salt) is selected. A process according to any one of claims 1 to 3, wherein the sulfur dye (S) is an insoluble, oxidized sulfur dye (S₁ '), the at least partially dissolved form (S _A ) of which is formed in the (R) -containing dye bath. Method according to one of claims 1 to 4, wherein the dyeing with at least one sulfur dye in at least partially soluble and at least partially reduced form (S _A ') is carried out under alkaline conditions. Process according to one of claims 1 to 5, characterized in that (R) is present in a smaller amount than would otherwise be necessary in order to obtain a stable reduction bath under the same conditions but without a reduced oxygen content of the atmosphere. Method according to one of claims 1 to 6, characterized in that the oxidation is carried out under neutral to acidic conditions. Method according to one of claims 1 to 7, which is carried out in a nozzle dyeing apparatus or in a reel runner. A method according to any one of claims 1 to 8, wherein the reduced oxygen atmosphere contains an added inert gas. Method according to one of claims 1 to 8, wherein the reduced oxygen content is generated by applying a vacuum or reduced pressure. The method of claim 9, wherein the gas added is nitrogen, a rare gas or carbon dioxide, or a mixture of two or more thereof. A method according to any one of claims 1 to 11, wherein (R) is used in combination with a chelating agent (C). Method according to one of claims 1 to 12, characterized in that the aqueous liquor is rinsed out under the atmosphere of reduced oxygen content. A method according to any one of claims 1 to 13, wherein the oxidation is carried out by adding a dissolved oxidizing agent (B). The method of claim 14, wherein (B) is a salt. Method according to one of claims 1 to 15, wherein after the coloring with (S _A ') and before the oxidation, the oxygen content of the atmosphere in the vessel is increased by adding oxygen. Concentrated leucosulfur dye preparation containing a leucosulfur dye (S₂), a sulfide-free reducing agent (R) and a chelating agent (C). A method according to claim 12, characterized in that a leucosulfur dye (S₂) is used in the form of a concentrated aqueous or dry preparation according to claim 14.