FR2676742A1 - NEW FORMS LEUCO DYES OF DYES IN SULFUR THEIR PREPARATION AND THEIR USE FOR THE DYEING OF CELLULOSIC MATERIALS AND POLYAMIDES. - Google Patents

Abstract

The subject of the invention is a process for preparing the water-soluble dry leuco form of a sulfur dye (L), a process according to which the sulfur dye (S) is reacted in an aqueous medium and at a temperature above 60 degree C with an effective amount of, (A) a reducing carbonyl compound in the presence of (B) an alkali metal hydroxide, and is dried.

Description

For dyeing substrates (eg cellulosic substrates)

  with sulfur dyes, the latter are advantageously applied in their leuco form, namely the dyes known as leuco sulfur dyes. Said dyes can be prepared by reducing the corresponding sulfur dyes with reducing agents, in particular with sodium sulphide. or with reducing sugars, for example with glucose, as

  described in British Patent Application 2,201,165.

  Since the reduction of sulfur dyes to provide the leuco form of such dyes causes the formation of mineral (poly) sulfides (mainly Na 2 S, Na 252 and / or Na HS) and / or the sulfide may be present in excess, which constitutes a disruptive element in the final product (because it can cause a release of H 2 S during the handling of the dye or when dyeing with said dye and / or leads to the presence of mineral sulphides in the waste waters of the dye), an attempt has been made to minimize the mineral sulphide content in the leuco form of sulfur dyes. Thus, British Patent Application 2,201,165 describes

  a process for the preparation of the leuco form of

  However, even if the mineral sulphide content can be as low as about 1%, it can still be a source of H 2 S. This content can even increase

  when storing the dye, because of a decomposition

  occasionally, by possible desulfurization of the oligosulfide bridges, which causes the formation of mineral sulfide which, in turn, can produce the undesirable H In addition, when these dyes are purified to obtain a mineral sulphide content of less than 1%, these dyes tend to oxidize in contact with the air This oxidation is favored in the liquid forms, so that at rest, in contact with the air, it can form an unwanted film of oxidized product on

  the surface of the liquid compositions of such dyes.

  The liquid (especially aqueous) forms of such

  dyes can oxidize or destabilize fast-

  during storage, which discourages their

  cialisation or even prevent from preparing in advance a stock solution which must be stored for a certain time before dyeing For such dyes, a

  minimum of about 2-3% of mineral sulphides is

  necessary to prevent oxidation and to

  marketing and storage of stock solutions.

  The Applicant has now found that

  can further reduce the amount of sulphide ions

  desirable and obtain a water-soluble leuco form of a sulfur dye having a high stability without having to use a reducing sulfide, when the sulfur dye is reduced to a high temperature in an aqueous medium in the presence of an alkali metal hydroxide and also preferably an alkali metal (bi) sulfide, with a reducing carbonyl compound as specified hereinafter, and the reaction mixture is

  dried directly, preferably at elevated temperature.

  The invention relates to a novel process, process products, compositions containing such products and dyeing substrates with said products. The invention therefore relates to a process for the preparation of the water-soluble leuco-dry form of a

  sulfur dye (L), a process according to which the colourant

  sulfur (S) is reacted in an aqueous medium and at a temperature above 601 C with an effective amount of (A) a reducing carbonyl compound in the presence of (B) an alkali metal hydroxide,

and is dried.

  According to a particular aspect of the invention, the reaction of (S) with (A) is also carried out in the presence of a sulphite and / or an alkali metal bisulfite.

  preparation of a stabilized and hydrous leuco form

  soluble sulfur dyestuff (L), wherein the sulfur dye (S) is reacted in an aqueous medium at a temperature above 601 C with an effective amount of (A) in the presence of (B) and C) an alkali metal sulfite and / or bisulfite,

and is dried.

  Sulfur dyes (S) are generally understood to mean the known dyes, defined for example as "Sulfur Dyes" and "Sulfurized Vat Dyes" in VENKATARAMAN "The Chemistry of Synthetic Dyes" Vol II (Chapters Xx XV and XXXVI) (1952 ) and Vol VII (1974) or defined for example in the "Color Index" as "Sulfur Dyes" and also as "Vat Dyes" with the additional indication "sulphur", as well as the structure number and the method of synthesis involving These are essentially dyes containing oligosulfide bridges linked to aromatic residues which can be reduced to thiol groups and can optionally have an oligomeric polymer structure.

  essentially by thionation of international products

  respective mediates at an elevated temperature, for example above 1000 C, in particular at a temperature between 110 and 3001 C (for example by heating the melt or in the presence of water

  and / or an inert organic solvent).

  The exact structure of the sulfur dyes is unknown or only partially known, even when the starting materials are known, since the number and / or position of the oligosulfide bridges, the number of sulfur atoms in an oligosulfide bridge, the number of heterocycles and / or NH bridges and / or the number of monomeric sequences in the sulfur dye molecule may vary depending on the

  starting materials and synthesis conditions.

  According to the invention, it is possible to use as sulfur dye (S) any known sulfur dye which can be reduced to leuco form, for example

  sulfur dyes and the sulfur dyestuffs pre-

  Known Leuk Sulphur or reduced Vat (Sulfur) Color Indexl: Leuco Sulphur Black 1, CAS: 6624111-0 Leuco Sulfur Black 2, CAS: 101357-26-0 Leuco Sulfur Black 11, CAS : 90480-94-7 Leuco Sulfur ICD Black 18, CAS: 90170-71-1 I Leuco Sulfur Red 10, CAS: 1326-96-1 I Leuco Sulfur Red 14, CAS: 68585-53-5 I Leuco Sulfur Blue 3, CAS: 85566-77-4 Leuco Sulfur Blue 7, CAS: 69900-21-6 Leuco Sulfur Blue 11, CAS: 90480-94-7 Leuco Sulfur Blue 13, CAS: 12262-26-9 CI Leuco Sulphur Blue 15, CAS: 100208-97-7 Leuco Sulfur Blue 20 CI, CAS: 85940-25-6 CI Reduced Vat Blue 43, CAS: 1327-79-3 CI Leuco Sulfur Green 2, CAS: 12262-32- 7 Leuco Sulfur Green IC 16, CAS: 70892-38-5 Leuco Sulfur Green 35 CI, CAS: 90170-23-3 Leuco Sulfur Green CI 36, CAS: 90295-17-3 Leuco Sulfur Brown CI 1, CAS: 1326- 37-0 CI Leuco Sulfur Brown 3, CAS: 100208-66-0 CI Leuco Sulfur Brown 10, CAS: 12262-27-0 CI Leuco Sulfur Brown 21, CAS : 97467-78-2 Leuco Sulfur Brown CI 26, CAS: 71838-68-1 I Leuco Sulfur Brown 31, CAS: 1327-11-3 CI Leuco Sulfur Brown 37, CAS: 70892-34-1 CI Leuco Sulfur Brown 52, CAS: 68511-02-4 Leuco Sulphur Brown 95 CI, CAS: 90268-97-6 Leuco Sulfur Brown CI 96, CAS: 85736-99-8 CI Leuco Sulphur Orange 1, CAS: 1326-49-4 CI Leuco Sulphur Yellow 9, CAS: 85737-01-5 CI Leuco Sulfur Yellow 22, CAS: 90268-98-7 especially the respective CI Sulfur Dyes or CI Vat (Sulfur) Dyes dyes (respectively the corresponding starting materials, when the synthesis

  sulfur dye and its reduction according to the invention.

  tion, are carried out in a single reaction

  which, according to the method of the invention, give

  the corresponding stabilized leuco form.

  The sulfur dyes (S) are preferably used in the form of an aqueous mass (P) containing (S), in particular in the form of an aqueous paste. The aqueous mass (P) can be prepared for example by suspending in water, a commercially available sulfur dye or a sulfur dye prepared by heating or melting the mass. Preferably, the aqueous mass (P) is the aqueous reaction mixture.

  from the preparation of the sulfur dye in pre-

  or a preferred aspect of the invention is an aqueous filter cake from the filtration of an aqueous reaction mixture obtained by thionation, which thionation reaction mixture may have been precipitated by example by oxidation and / or acidification; according to another particular aspect of the invention, (P) is a reaction mixture obtained

  by thionation, reduction with a sulphide and re-pre-

  cipitation of the dye by oxidation (for example with air) or (P) is a filter cake from

  filtration of such a reaction mixture.

  The reducing agent (A) is preferably aliphatic and is preferably a carbonyl compound having, at the α-position of the carbonyl group, a donor as a substituent; it is preferably a hydroxyl group, optionally etherified, in particular a methoxy group, or an optionally acetylated amino group. As (A), mention may be made of aliphatic compounds containing from 3 to 6 carbon atoms, in particular especially 1-hydroxyacetone, carbohydrates containing from 3 to 6 carbon atoms and derivatives thereof in which one or more of the hydroxy groups present are etherified with a methyl group or replaced by an amino group or an acetylamino group, in particular those aldoses and ketoses and their oligomers and / or their deoxy derivatives and the corresponding uronic acids The preferred carbonyl compounds (A) have the following formulas:

R 1 R 1

R 3 -HO R 3 O-CH OH

  R 2 (1) MR 2 (II) wherein one of R 1 and R 2 is hydrogen and the other is -OH, -OCH 3 or -NH 2, R 3 is -CH 3, -CH OH, -CHO or -COOM, M means hydrogen or a cation and

  n is an integer from 1 to 5.

  M advantageously means a cation

  color, preferably an alkali metal cation, more

preferably sodium.

  When in the formula (I) N means an integer from 2 to 5, the N symbols R 1 may be identical or different and the N symbols R 2 may be identical or different In the formula (I),

  one of R 1 and R 2 means hydrogen and the other signifies

  preferably a hydroxy group; in formula (I), R 3 preferably means -CH 2 H or, when n is from 2 to 5, also a carboxy group; in the

  formula (I), N preferably means 3 or more

  When N stands for 3, 4 or 5 in the

  formula (II), the (n-1) symbols R 1 may be identical

  different and different (n-J) symbols R 2 may be identical or different In formula (II), one of the two symbols R 1 and R 2 signifies hydrogen and

  the other preferably means a hydroxy group.

  When N is 1 in formula (II), R 3 preferably means - CH 3 or -CH 2 OH; when N is 2, 3, 4 or 5 in formula (II), R 3 is preferably -CH 2 O. Among the compounds of formula (II),

  those in which N stands for 1, 3 or 4

  saccharides of formula (I) and formula (II) may also be in pyrannosic or furanic form; the uronic acids of formula (I) and of formula (II) may also be in the form

of lactones.

  Suitable reducing sugars include, in particular, aldopentoses, especially arabinose, ribose and xylose, and hexoses, especially glucose, fructose, mannose and the like.

  galactose and their desoxy, disdesoxy and amino derivatives

  Deoxy (A) can also be used oligosaccharides, especially disaccharides, especially sucrose, lactose, maltose, melibiose and cellobiose, and tri-, tetra and pentasaccharides, especially melezitose and raffinose, and other syrups such as corn syrup, malt syrup and molasses containing reducing sugars The preferred reducing sugar is glucose. The amount of (A) used should be sufficient to achieve substantially complete reduction of the sulfur dye (S) used. The required amount of (A) and also the preferred amount of (A) can vary depending on the sulfur dye, the synthesis method used for its preparation and the compound (A) chosen is advantageously used between 1 and 40, preferably between 5 and 15% by weight of (A) by

  relative to the weight of the final product (L) in the dry state.

  Expressed in relation to the weight of the active ingredient which here represents the total amount of polymer products obtained in the preparation of the sulfur dye

  (S), the amounts of (A) used are advantageously

  between 1 and 80, preferably between 5 and more preferably between 10 and 20% by weight. The appropriate or particularly preferred amount of (A)

  can be determined by preliminary tests.

  Since (B) is a dry or preferably aqueous alkali metal hydroxide, especially aqueous lithium, sodium or potassium hydroxide, preferably sodium or potassium hydroxide solutions (B) may be used in the form of usual aqueous solutions, in particular at a concentration of> 10% by weight, preferably> 20%

  by weight, preferably at a higher concentration

  higher, so that the amount of water to be evaporated and the evaporation time are minimized (B) is preferably used in the form of 30-50% aqueous alkali metal hydroxide, especially in the form of hydroxide The amount of (B) that is reacted can vary, not only according to (S), but also as a function of (A) and (C) and their relative amounts. The amount and concentration alkali metal hydroxide are advantageously chosen so that an excess of alkali metal hydroxide, i.e. metal hydroxide

  alkali (B) which does not react, is present, advantageously

  Preferably, an excess of 0.5 to 20%, preferably 3 to 10% by weight, based on the weight of the final product (L) in the dry state, expressed in relation to the weight of the active ingredient (as defined above). ), the

  quantities in excess of (B) are advantageously

  between 1 and 40, preferably between 5 and 20

  weight The concentration of (B) in the mixture

  The reaction medium is such that the pH is greater than 12, preferably greater than 14. In the reaction medium, the concentration of alkali metal hydroxide is such that it is present as a 1 N solution at 12 N, preferably 2.5 N at 8 N, relative to the total amount of water present in the reaction medium In the concentrated aqueous solution of alkali metal hydroxide, the reducing sugars can form reductones. As (C), lithium, sodium or potassium sulfite or bisulfite or a mixture of two or more of these compounds,

  preferably sodium sulphite and / or more preferably

  Sodium bisulphite (C) is advantageously used in an amount of from 1 to 40, preferably from 2 to 24, more preferably from 5 to 10,% by weight, based on the weight of the stabilized product (L). Dry state Expressed in relation to the weight of the active ingredient (as defined more

  above), the quantities used of (C) are advantageously

  between 1 and 80, preferably between 5 and

  more preferably between 10 and 20% by weight.

  The weight ratio of (A) to (C) may vary widely, in particular between 1:10 and 10: 1, advantageously between 1: 5 and 5: 1, preferably between 2: 1 and 1: 2, more preferably between

1: 1.5 and 1.5: 1.

  The total water content of the mixture

  at the beginning of the reaction must be at least such that it allows the mixture to be stirred easily and that the aqueous phase represents the continuous phase and is advantageously <95%, preferably> 8% by weight; it can vary according to the reaction products used The water content of the reaction mixture at the beginning of the reaction is at least 10%, in particular

  from 10 to 90%, preferably from 20 to 80% by weight.

  The water content of (P) can vary widely

  according to its preparation, and may advantageously be between 5 and 95%, preferably between 10 and 90% by weight relative to the total weight of (P) When (P) is the reaction mixture resulting from the thionation in medium aqueous (and, depending on the dye, possibly precipitation by acidification and / or oxidation) for the preparation of the sulfur dye (S), it can be used as it is or can be filtered beforehand, the choice depending essentially on the content of water, mineral sulfides and / or salts of the dye suspension, and also its filterability and the desired concentration of dry dye. Reaction mixtures having a water content of> 95% by weight or even> 90% by weight are preferably subjected to filtration (if necessary in the presence of a filter aid) The water content can be substantially reduced by filtration and represent for example between 8 and 90% by weight of the filter cake, depending on the consistency of the dye in suspension, the filtration system and the presence or absence of a filter aid The water content of (P) is comprised of

  preferably between 20 and 80% by weight.

  The reduction is carried out at temperatures

  It is preferred that they are higher than 600.degree. C., advantageously between 65.degree. and 2000.degree. C., preferably between 95.degree. and 1901.degree. C., if necessary under pressure, in particular at a temperature between 100 and 140.degree. C., especially for prolonged periods of reaction (ie to say> 1

  hour, in particular between 2 and 30 hours,

  with at least partially simultaneous drying as described below) and higher temperatures.

  in particular between 130 and 1900 C, more preferably

  between 145 and 1900 C for short reaction times as described hereinafter, especially with at least partially simultaneous drying (i.e. <1 hour, in particular between 2 and 30 minutes or 4 and

minutes).

  The reaction may be carried out with exclusion of oxygen, in particular air, for example under nitrogen, or preferably without exclusion of air. The reaction is advantageously continued until the corresponding leuco-form reduction is substantially complete. that is, until the reduction product obtained is easily and completely soluble in water and is substantially free of insoluble and unreduced sulfur dye residues. This can be demonstrated by a simple test of water solubility, for example by dissolving with stirring 5 g of the reduction product in 95 g of demineralized water at room temperature (= 201 ° C.) until complete dissolution of the soluble product in a 5% solution and filtration through a filter paper from "Schleicher & Sch ll" 589/2 A completely soluble product does not leave undissolved particles on the filter The fact that the reduction is practically complete and that the reduced product is easily soluble in water means that most

  or virtually all the oligosulfide bridges of the colo-

  sulfur (in particular at least 95%, preferably

  The process of the invention can be carried out in two steps, first comprising reduction to obtain an alkaline aqueous solution of the leuco form of the sulfur dye and

  drying of the resulting solution, or preferably

  the reduction and evaporation of water (drying) being carried out simultaneously or in part at the same time (in this case, the reduction is completed during drying). As for the reduction, the drying can be carried out in a single step. carried out in the presence or absence of air, for example under nitrogen When the process is carried out in 2 steps, preferably at least one of the two stages, the reduction and drying, is carried out in the presence of air; more preferably, both reduction and drying are carried out in the presence of air. The reaction time may vary widely depending on the apparatus used, the composition of the reaction mixture and the reaction parameters and may be between 2 minutes and 30

  hours, preferably between 4 minutes and 12 hours.

  The drying is preferably carried out at temperatures above 60.degree. C., in particular between and at 200.degree. C., advantageously between 95.degree. And 1901.degree. C., especially between 100.degree. And 1400.degree. C., especially for long drying (> 1 hour, especially between 2 and 30.degree. hours), and between 130 and 1900 C, preferably between 145 and 1901 C for short drying (<1 hour, especially between 2 minutes and 30 minutes) According to one aspect

  of the invention, the reaction mixture is dried

  at a temperature substantially identical to that used for the + 200 reaction, preferably + The drying can be carried out according to the usual methods and in known apparatuses (for example in evaporators), for example by spray drying or layer drying thin (for example on carrier ribbons heated for example by infra-red radiation, microwaves or by other devices, or on drying drums heated for example by steam or provided with heating envelopes) and, if necessary the dried product can be pulverized to obtain the desired particle size, resulting in a reduced, dry and water-soluble product, for example in the form of granules,

powder or scales.

  When the reaction is carried out at least partly simultaneously with the evaporation (drying) of the aqueous mixture, according to the preferred embodiment of the invention, the total time required for evaporation depends on the drying system used, the temperature used, the consistency of the mass and its thickness, and can vary widely for example between 4 minutes and 30

  hours, preferably between 5 minutes and 12 hours.

  Thus, with continuous systems such as thin film drying on conveyor belts or in drying drums or by spray drying, the drying time and in particular the total time

  necessary for the implementation of the process of the in-

  It can be as short as 4 to 30 minutes, preferably 5 to 20 minutes. The reaction mixture is preferably directly dried, so that the reduction takes place during the evaporation of the water to obtain directly in one step the reduced product

and dry.

  As dry product, in particular as dry product (L), is meant a solid leuco form of sulfur dye obtainable by drying as described above, especially with a content of

  water <5%, preferably <2% by weight.

  According to the process of the invention, it is possible to obtain in a very simple manner and without the addition of other reaction products (in particular without addition of sulphide) and auxiliaries (in particular in the absence of surfactants). -active), forms

  leuco stabilized sulfur dyes (L) concentration

  are substantially free of sulphide ions, in particular in which the mineral sulphide content of the dry product is less than 1%, more particularly even less than 0.2% by weight, and even products which are free of sulphides

  minerals (as evidenced by the analytical methods

  usual ticks with a sensitivity of 0.01%) and which, in the presence of acids, do not release organoleptically detectable H 2 S In addition, the dyes (L) obtained have excellent stability to oxidation atmospheric in their solid form and also

  particularly in the form of

  aqueous mother preparations (as prepared in general

before dyeing).

  The leuco-dry forms of sulfur dyes (L) are readily soluble in water and can be formulated as liquid compositions, in particular aqueous compositions, by simple dilution with water, aqueous solutions of high concentration which can even be obtained, in particular from a

  concentration> 5% by weight of (L) up to the concentration

  saturation treatment For the formulation of

  concentrated concentrations, containing for example from 5 to 50, preferably from 10 to 40% by weight of (L), it may be advantageous to add formulation auxiliaries,

  solubilizers and / or hydrophilic agents

  tropes, for example urea, a C 1 -C 4 alkyl monoether of mono-, di or triethylene glycol, a C 1 -C 4 alkyl monoether of mono-, di or tripropylene glycol, mono-, di or triethanolamine or mono-, di or

  triisopropanolamine, and / or anionic surfactants

  for example sulpho-containing surfactants having from 6 to 24 carbon atoms in lipophilic residues (for example sodium xylene sulphonate, lignin sulphonate or dinaphthylmethane disulphonate) and / or reducing stabilizers chosen for example from the usual redox products

  free from sulphides, such as thiourea dioxide.

  Such liquid compositions, in particular those of the products (L) obtained in the presence of (C), are very stable and their tendency to form on the surface, by oxidation by the action of air, an annoying film is also considerably reduced, even when diluted in water prior to dyeing to form stock solutions, so that the concentrated liquid compositions can be transported and / or stored for several days or weeks without disturbing alteration of the composition, and stock solutions can be prepared and stored,

  if necessary, before dyeing without

  troublesome ration, especially without formation, by oxidation, an undesirable film on the surface of the solution. The stabilized leuco forms of sulfur dyes (L> thus obtained can probably be considered as (hemi-thioacetals of the compounds

  reducing carbonyls (A) (or corresponding reductones)

  as leuco form of sulfur dyes in which at least a portion of the mercapto groups or their salts have reacted with the reducing carbonyl group to give the corresponding (hemi) thioacetal which is stabilized during drying, which makes the dye stable to oxidation by

air and internal disproportionation.

  The products (L) obtainable according to the process of the invention are low affinity, water-soluble dyes which are suitable for dyeing textile or non-textile substrates dyeable with sulfur dyes; those obtained in the presence of (C) have a water solubility and

  excellent stability also in pre-diluted form (especially in the form of stock solutions); those obtained in

  the absence of (C) are also particularly suitable for coloring the paper They are advantageously applied to the substrate in their leuco form and are then oxidized

  on the substrate, which gives the oxidized form corresponding to

  (this process is particularly suitable for dyeing cellulosic textile materials) or are fixed by another method, for example by precipitation on the substrate (especially when using a binder or a primer) or by fixing on the binder or primer which is fixed on the substrate, in particular for primed textiles,

  bonded nonwovens or bonded paper.

  As materials that can be dyed with

  dyes of the invention in an aqueous medium with oxy-

  subsequent dyeing or other fixation of the dye, in particular fibrous materials,

  mainly cellulosic materials and poly-

  natural or synthetic amides (for example wool, leather or synthetic polyamides) The fibrous substrate may be in any form usually used for dyeing, for example in the form of fluff, filaments, yarns, skeins, skeins, bobbins, nonwovens, felts, woven or knitted articles, carpets, velvets, tufted fabrics and semi-finished or finished articles The colorant may be applied by typical, for example by exhaustion (in short or long bath, for example with a ratio between 1: 2 and 1: 120, preferably between 1:10 and 1:40)

  or by impregnation (for example by padding, immersing

  spraying, application of foam or printing

  The dyebaths may also contain additives, in particular wetting agents, leveling agents, sequestering agents, builders, reducing agents and / or

  other additives from, for example, the use of

  Dyestuffs in the form of liquid formulations, in particular as described above Advantageously, the dyebath contains a reducing agent

  sulphide-free, for example sulphide formaldehyde

  xylate, thiourea dioxide, sodium or potassium dithionite or a carbonyl compound, preferably as defined above for (A), in particular

  hydroxyacetone or a mono or oligosaccharide

  ductor, preferably glucose; the reducing compound is advantageously present in the dye bath at

  a concentration of between 5 and 100, preferably

  Between 10 and 80% by weight based on the weight of the dyestuff. For impregnation, the bath can contain,

  if necessary, a thickening agent.

  Exhaustion dyeing can be carried out on textiles at temperatures

  usual, for example between 60 and 1400 C, if ne-

  under pressure, on textile materials

  cellulosic and / or poly-textile materials

  synthetic amides at temperatures advantageously between 90 and 1350 ° C, for example under HT (high temperature) conditions, preferably

  between 102 and 1300 ° C., or preferably at 900 ° C.

  in particular between 950 C and boiling, and

  under conditions of neutral to basic p H (preferably

  at a pH> 7.5, more preferably> 12, for example at a pH of 12 to 14), preferably with the addition of a reducing agent as indicated above and suitably with an adequate amount of an alkali metal hydroxide, in particular NaOH, and advantageously a water-soluble mineral salt such

  usually used in exhaust dyeing.

  such as chloride, sulphate or

  sodium carbonate, to facilitate the climb.

  The impregnating baths may have a composition similar to that of the exhaustion baths, and at a concentration suitable for the chosen application, and may also contain other additives suitable for the chosen impregnation method, for example thickeners. The impregnated articles may be fixed according to the usual methods, for example by heating, preferably at temperatures> 1000 ° C., for example with dry heat, for example between 130 ° C. and 180 ° C., or preferably by steam treatment. for example between 100 and 1050 C. The dyeing is advantageously completed by fixing the dye, essentially by oxidation or by another method. The oxidation can be carried out with the usual oxidation agents, for example with air oxygen, peroxides or halogenated oxidizing compounds (eg alkali metal bromates, iodates, chlorates or chlorites) at a pH to preferably between 4 and 8, in particular between 4.5 and 7.5 when the oxidation is carried out with halogenates, peroxides, oxygen or air, or at an alkaline pH, in particular between 8 and 11, more preferably between 9 and 10.5 when the oxidation is carried out with alkali metal halogenites, especially sodium chlorite. Peroxides, in particular H 202, can also be used under alkaline conditions. tap water or (partially) demineralized water as commonly used in dyeing plants contains a small amount of dissolved oxygen, oxidation can also be carried out by rinsing with quantities

significant amounts of water.

  Fixation of the dye by a method other than oxidation may for example be carried out by precipitation with a suitable auxiliary or attachment to a suitable auxiliary used as fixing agent or finishing resin for example on textiles or nonwovens, or used as a flocculation agent, de-watering agent or agent

  retention and / or bonding agent for the pre-

  paration of the paper, in particular the calcium or aluminum salts, preferably aluminum sulphate (which is particularly suitable for coloring

paper).

  The paper is advantageously colored in the mass, preferably in the form of a suspension

  aqueous pulp, preferably at temperatures of

  between 15 and 400 ° C. (or more simply at room temperature) and preferably at a pH of between 8 and 11 μl, especially as is the case when a dye (L) containing a metal hydroxide is dissolved. The dye can then be precipitated onto the fibers by the addition of a suitable sizing agent and / or dripping agent or retention agent, preferably under weakly acidic conditions, in particular at a pH of between 4.5 and 6.5, or to set it for example on

the gluing agent.

  Dyes with optimum yields and fastnesses are obtained. During dyeing, a minimum of soiling is formed in the dyeing machines. Using the leuco form of the sulfur dyes (L) of the invention, the release of hydrogen sulphide

  disturbance and / or formation of inorganic sulphides

  desirable in wastewater dyeing.

  The following examples illustrate the invention without in any way limiting its scope. In these examples, the percentages are by weight and the

  temperatures are given in degrees Celsius

  The solubility of the products is determined according to the following method: 100 ml of a 5% solution of the reduction product are prepared in demineralized water at 200, and the mixture is stirred until the product is completely dissolved (this takes about 5 minutes). ) and filtered on paper filter Schleicher & Schilll 589/2 of 7 cm in diameter; Filtration of the product easily and completely dissolved lasts a few seconds and does not

  leave no undissolved residue on the filter.

  The sulphide content of the product can be determined as follows: in a first container, it is acidified with 2 ml of 80% acetic acid, 100 ml of a 1% solution of the product in distilled water and collected. any release of H 2 S by passing through the solution a current of C 02 or N 2 that one

  then move on to one or more other

  containers which contain a liquid capable of fixing H 2 S (for example an aqueous solution of a metal oxide or hydroxide or a heavy metal salt) in which the sulphide can be analyzed according to the usual methods.

Example 1

  a) For 2 hours, 1000 g of 2,4-dinitrochlorobenzene is reacted with 169 g of a 50% aqueous solution of sodium hydroxide. The product obtained is added to a mixture of 200 g of sodium sulphide in 200 g of water and 127 g of sulfur The mixture is brought to 116-1200 and heated at reflux at this temperature for 10-15 hours. The mixture is then diluted with 200 g of water and aerated at room temperature. passing air through the solution until the dye precipitates The resulting mixture is then filtered and washed with water to give a black dye filtration cake having a water content

40-60%.

  b) In a 1-liter evaporation vessel, this filter cake is mixed with 100 g of a 50% aqueous solution of sodium hydroxide and 26 g of glucose. This mixture is heated to 120-1300 ° C. and maintained at 120-1300 for 12 hours until dry. 260 g of a dry black product (1) is obtained which is easily and completely soluble in water, which is free of mineral sulfides and stable in water. oxidation by air

  even as a 1% aqueous solution.

Example 2

  a) For 2 hours, 1000 g of 2,4-dinitrochlorobenzene are reacted with 169 g of a 50% aqueous solution of sodium hydroxide. The product obtained is added to a mixture consisting of a solution of 200 g. of sodium sulphide in g of water and 127 g of sulfur. The mixture is brought to 116-1200 and then heated to

  reflux at this temperature for 10-15 hours.

  b) 100 g of a 50% solution of sodium hydroxide and 35 g of glucose are then added, and the resulting mixture is reacted and dried at 120-130 in a 1 liter evaporation vessel for 12 hours. hours 590 g of a dry black powder (2) is obtained which is easily and completely soluble in water and whose sulfur content

sodium is <0.1%.

  Examples 3 and 4: The procedure is as described in Example 1 and

  example 2, but instead of 2,4-di-

  nitrochlorobenzene, a mixture in equi-

  of picric acid and 2,4-dinitrochlorobenzene.

  The respective products obtained, the products (3) and (4), are easily and completely soluble in water. Examples ibis at 4 bis: The procedure is as described in Examples 1, 2 and 4, but instead of glucose an equivalent quantity of maltose is used. The dry products obtained, the products (la), (2 a), (3 a) and (4 a), are

  easily and completely soluble in water.

  Examples 1 ter to 4 ter: The procedure is as described in Examples 1, 2 and 4, but instead of glucose an equivalent amount of lactose is used. The dry products obtained, the products (1b), (2b), (b) and (4 (b), are

  easily and completely soluble in water.

  Examples 1c to 4c: The procedure is as described in Examples 1, 2 and 4, but instead of glucose an equivalent amount of xylose is used. The dry products obtained, the products (1c), (2c), (c) and (4c), are

  easily and completely soluble in water.

Example 5

  a) 200 g of thionation product obtained by reacting sodium polysulfide with sulfonated copper phthalocyanine (having 4 sulfo groups) are diluted with water and oxidized with air until the dye precipitates. The mixture is neutralized with sulfuric acid, filtered off and washed with water to give 560 g of filter cake of a green dye.

having a water content of 80-85%.

  b) In a 1-liter evaporation vessel, 250 g of this filter cake are mixed with water, 34 g of a 50% aqueous solution of sodium hydroxide and 13.5 g of glucose. the mixture is heated to 1000 and maintained at this temperature for 10 hours. 60 g of a green dye powder (5) in reduced form, which contains 5% by weight of NaOH relative to the weight of the final product, are obtained. dry state; the dye is free of mineral sulphides, is easily and completely soluble in water and dyes the cotton in an intense green shade,

  when applied in the presence of

  appropriate drivers (eg glucose) and

  of sodium hydroxide with subsequent oxidation.

Example 6

  a) At 2800, a mixture of 45 g of sulfur is heated for 24 hours in a rotary drum,

  54 g of 60% sodium sulfide and 45 g of 2,4-di-

  Aminotoluene The solid product obtained is dissolved in 500 g of water and 20 g of Na OH for 3 hours at 1000. The mixture obtained is diluted with 500 g of water and air is passed through the solution until oxidation of the sulphide and precipitation of the dye The pH 7 is then adjusted by addition of sulfuric acid, the resulting mixture is filtered off and

  the filter cake is washed with water.

  b) The filter cake obtained (having a water content of 75-85%) is mixed with 50 g of a 50% aqueous solution of sodium hydroxide, 18 g of glucose and 50 g of water. react and the mixture is simultaneously dried in an evaporation vessel for 10 hours at 120-130. 110 g of the leuco-dry form of a dye are obtained

  brown sulfur (6) which is easily and completely

  water-soluble and which, when suitably applied in the presence of a reducing agent as indicated above (eg glucose) and NaOH and then oxidized, gives dyes with a slight yellowish brunette

intense on the cotton.

Example 7

  250 g of the filter cake obtained in Example 1a) are mixed with 66 g of aqueous sodium hydroxide solution and 16 g of glucose. An evaporation vessel is charged with 20 g of this mixture. A thin layer is heated to 1650 and dried for 8 minutes. 7 g of a dry black product (7) is obtained which is easily and completely soluble in water, is free of mineral sulphides and is stable on the surface. oxidation by air even in form

a 1% solution.

The filter cakes of Examples 5 (a) and 6 (a) and the refluxed mixture of Example 2 (a) can be reduced and dried in a manner analogous to

  that described in Example 7 for the filter cake.

example).

Example 8

  In a 1 liter evaporation vessel, the filter cake obtained is mixed with the example

  la), with 120 g of a 50% aqueous solution of hydro-

  sodium hydroxide, 28 g of glucose and 28 g of sodium bisulfite. This mixture is heated to 120-1400 and maintained for 8 hours at 120-140 until the mixture is dry. reduced solid black product (8) which is easily and completely soluble in water, is free of mineral sulfides and is stable to oxidation by air, even in the form of

of a 1% aqueous solution.

Example 9

  To the product obtained in Example 2 a), g of a 50% aqueous solution of sodium hydroxide, 35 g of glucose and 25 g of sodium bisulfite are added and the mixture obtained is reacted and dried. 12 hours at 120-1300 in a 1 liter evaporation vessel 626 g of a dry black powder (9) is obtained which is easily and completely soluble in water

  and has a sodium sulfide content <0.1%.

  Examples 10 and 11: The procedure is as described in Examples 8 and 9, but an equimolar mixture of picric acid is used.

  and 2,4-dinitrochlorobenzene in place of 2,4-di-

  nitrochlorobenzene The dry products (10) and (11) obtained are easily and completely soluble in water. Examples 8 bis to 11 bis: The procedure is as described in Examples 8, 9 and 11, but an equivalent quantity of maltose is used in place of glucose. The dry products obtained respectively (8 a), (9 a), a) and (11 a) are

  easily and completely soluble in water.

  Examples 8b to 11b: The procedure is as described in Examples 8, 9 and 11, but an equivalent amount of lactose is used in place of glucose. The dry products obtained respectively (8b), (9b), (b) and (11 b) are

  easily and completely soluble in water.

  Examples 8c to 11c: The procedure is as described in Examples 8, 9 and 11, but an equivalent amount of xylose is used in place of glucose. The dry products obtained

  respectively (8c), (9c), (10c) and (11c) are easily

  completely soluble in water.

Example 12

  In a 1-liter evaporation vessel, 250 g of the filter cake obtained in Example 5 (a) are mixed with 120 g of water, 44 g of a solution

  aqueous 50% sodium hydroxide, 13.5 g of

  sodium sulphite and 13.5 g of glucose, the mixture is heated to 100 and maintained at this temperature for 10 hours. 72 g of a green dye powder (12) in reduced form, which contains 5% of NaOH based on dry final product weight, is free of mineral sulfides, easily and completely soluble in water and dyes cotton to an intense green shade when applied in the presence of suitable reducing agents (for example,

  glucose) and sodium hydroxide with sub-

secant.

Example 13

  a) For 24 hours, one warms up to 300

  mixture of 140 g of sulfur and 45 g of 2,4-diamino-

  toluene in a rotary drum The solid product obtained is dissolved in 200 g of water and 150 g of NaOH for 2-4 hours at the boiling point. The mixture obtained is diluted with 800 g of water and the mixture is stirred. air through the solution until oxidation of the sulfide and precipitation of the dye is then adjusted to pH 7 by addition of sulfuric acid, the resulting mixture is filtered and washed the cake of

filtration with water.

  b) The filter cake obtained (having a water content of 75-85%) is mixed with 60 g of a 50% aqueous solution of sodium hydroxide, 18 g of glucose and 15 g of sodium bisulfite. The mixture is reacted and the mixture is simultaneously dried in an evaporation vessel for 10 hours at -1300. 130 g of the dry leuco form are obtained.

  orange sulfur dye (13) which is easily

  completely soluble in water and which, suitably applied in the presence of a reducing agent as indicated above and Na OH with subsequent oxidation, gives dyes

  an intense yellowish orange hue on the cotton.

Example 14

  250 g of the filter cake obtained in Example 1a) are mixed with 64 g of a 50% aqueous solution of sodium hydroxide, 15 g of glucose and 16 g of sodium bisulfite. 28 g of this mixture are introduced. as a thin layer in an evaporation vessel heated to 150- 1600 and dried for minutes 7 g of a dry black product (14) is obtained which is easily and completely soluble in water,

  is free of mineral sulphides and is stable to oxy-

  dation by air even in the form of an aqueous solution

at 1%.

  The filter cakes of Examples 5 (a) and 6 (a) and the refluxed mixture of Example 2 (a) can be reduced and dried in a manner analogous to

  that described in Example 14 for the filter cake.

example).

  Composition 1: 50 g of the dry product (1) of Example 1 are dissolved in 210 g of water, with 66 g of urea, g of diethylene glycol ethyl ether and 10 g of 40% aqueous sodium xylenesulphonate solution. and heated to 700 for 20-30 minutes. Then cooled to 40 and treated with 10 g of monoethanolamine and 2.5 g of thiourea dioxide. A good solution of the reduced dye, which is free of sulfides and polysulfides, is obtained. has a high stability to oxidation and film formation and also low affinity for cotton; by applying the leuco dye to the cotton in the presence of a suitable reducing agent as indicated above (for example glucose) and sodium hydroxide with subsequent oxidation, dyes of an intense black shade with excellent fastness. Compositions 7, 8 and 14: The procedure is as described for composition 1, but using 50 g of product (7), (8) or (14) in place of product (1), good dye solutions are obtained. respective reductions which are free of sulfides and polysulfides and have high stability to oxidation and film formation and also low affinity for cotton; by applying these leuco dyes to the cotton in the presence of a suitable reducing agent as indicated above (by

  glucose) and sodium hydroxide with oxy-

  Subsequently, shade dyes are obtained.

  intense black with excellent fastness.

  Compositions 2, 3, 4, 5, 6, 9, 10, 11, 12 and 13: The procedure is as described for composition 1, but products (2), (3), (4), (5) are used respectively. ), (6), (9), (10), (11), (12) and (13) in place of the product (1), in amounts corresponding to

respective solubilities.

  Application Example A: 5 g of leuco (1) sulfur dye powder obtained in Example 1 are dissolved in 1 ml of water containing 0.1 g of EDTA (sodium salt of ethylenediamine tetraacetic acid). 0.1 g of a commercial wetting agent (alkyl phosphate) is then added 2.5 g of dextrose and 2.0 g of a 50% aqueous solution of sodium hydroxide and diluted mixture obtained with cold water to a total volume of 100 ml With this bath, a cotton cloth of 10 g (50 cm x 8 cm) is padded to a absorption rate of 100% and steamed for 1 minute at 1020 The treated fabric is then rinsed with water and oxidized for 1 minute at 50 in a solution of 7 g / liter of hydrogen peroxide at 30% and 7 g / liter 80% acetic acid The treated fabric is then dried. An intense black shade is obtained with good fastness to washing, rubbing and light. After the dyeing, the machine used e for dyeing is cleaner than after dyeing obtained in the same manner but with a dye containing sodium sulphide and obtained according to conventional methods known in the art. Abis Application Example: The procedure is as described in Application Example A, but the sulfur dye powder in leuco (7), (8) or (14) form is used in place of the dye powder. with sulfur in leuco form

  (1) Intense black dyes are obtained

  feeling good fastness to washing, rubbing and light After dyeing, the machine used for dyeing is cleaner than after dyeing

  obtained in the same way but with a coloring agent

  sodium sulphide and obtained by conventional methods. Application Example B: 1 g of the leuco (1) leuco dye dry powder obtained in Example 1 is added to a solution of 200 ml of water, 0.2 g of EDTA, 0, 2 g of a

  wetting agent (as used in the application example

  A), 0.8 g of dextrose and 0.8 g of a solution

  50% sodium hydroxide solution and shake until

  solution of the dye In this bath, a skein of cotton of 10 g is introduced, the bath is heated for minutes at 950 by stirring the skein continuously and

  then hold it for 20 minutes at this temperature.

  8 g of sodium chloride are then added, the dyeing is continued for 30 minutes at 95, the skein is removed from the bath, washed with water and treated for 15 minutes at 50 with a solution of 0.5 g / liter of hydrogen peroxide and 0.5 g / liter of acid

  acetic acid for oxidation of the dye After oxidation

  wash and dry the skein.

  intense black dye with good fastness.

  Application Example Bbis: The procedure is as described in Application Example B, but the sulfur dyestuff powder in leuco (7), (8) or (14) form is used in place of the dye powder. with sulfur in leuco form

  (1) Intense black dyes are obtained first

feeling good solidity.

  In application examples A and B, the dyestuff powders (1), (7), (8) and (14) of Examples 1, 7, 8 and 14 can be replaced by dyestuff powders (2). (3), (4), (5), (6), (1a), (2a), (3a), (4a), (1b), (2b), (3b), ( 4 (b), (lc), (2c), (3c), (4c), (9), (10), (11), (12), (13), (8a), (9) a), (10), (11a), (8b), (9b), (10b), (11b), (8c), (9c), (10c), and (llc), which gives dyes of corresponding shade In place of dry powders, it is possible to use the

  corresponding liquid formulations 1 to 14.

  Application Example C: 0.5 g of the black powder of the sulfur dye in leuco (1) form obtained in Example 1 Au are introduced with stirring in 500 ml of a 1% suspension of paper pulp. After 10 minutes, 0.1 g of glue is added to the resin (sodium rosinate) and a sufficient amount of aluminum sulphate to obtain a pH between 4.5 and 5.0, which causes the precipitate to precipitate. dye on the pulp From this

  colored pulp, a sheet of paper is formed.

  The paper is colored in an intense black shade and the residual bath is completely transparent, colorless and

free of mineral sulfides.

  By proceeding in an analogous manner, it is possible to use the powders of the leuco forms of sulfur dyestuffs (2), (3), (4), (5), (6), (7), (la), (2 a) , (3a), (4a), (1b), (2b), (3b), (4b), (1c), (2c), (3c), and (4c), which gives colorings on the paper of corresponding shades In the place of the dry powders,

  the corresponding liquid formulations can be used

1 to 7.

Claims (14)

REVENDI CATI ONS   1 a process for preparing the water-soluble leuco-dry form of a sulfur dye (L), characterized in that the sulfur dye (S) is   to react in an aqueous medium and at a higher temperature   less than 600 C with an effective amount of (A) a reducing carbonyl compound in the presence of (B) an alkali metal hydroxide, and is dried.   A process according to claim 1 for the preparation of the water-soluble form of a sulfur dye (L), characterized in that the sulfur dye (S) is reacted in an aqueous medium and at a temperature above 600 with an effective amount of (A) in the presence of (B) and (C) a sulfite and / or an alkali metal bisulfite, and is dried.   A process according to claim 1,   characterized in that the total water content of the   aqueous mixture of (S), (A) and (B) at the beginning of the reaction is <95% by weight.   A process according to claim 2,   characterized in that the total water content of the   aqueous mixture of (S), (A), (B) and (C) at the beginning of reaction is <95% by weight.   A process according to claim 3, characterized in that the aqueous mixture of (S), (A) and (B) at the start of the reaction has a water content of 20 to % in weight.   A process according to claim 4, characterized in that the aqueous mixture of (S), (A), (B) and (C) at the beginning of the reaction has a water content from 20 to 80% by weight.   7 A process according to any one of   Claims 1 to 6, characterized in that it is dry without exclusion of air.   8 A process according to any one of   Claims 1 to 7, characterized in that react without exclusion of air.   9 A process according to any one of   Claims 1 to 8, characterized in that (S) is   used in the form of an aqueous mass (P) containing (S). A process according to claim 9, characterized in that (P) is an aqueous reaction mass of the sulfur dye preparation (S),   having a water content of 8 to 95%.   A process according to claim 9 or   characterized in that (P) is a filter cake   wet treatment with a water content of 8 to 95%.   12 A process according to any one of   Claims 1 to 11, characterized in that (A) is a aldosis or ketosis.   13 A process according to any one of   Claims 1 to 12, characterized in that the drying   is performed at least partly simultaneously with the reduction. A leuco-dry form of a sulfur dye (L), obtainable by the process   specified in any one of claims 1 to 13.   A leuco-dry form of a sulfur dye (L) according to claim 14 and containing a   excess alkali metal hydroxide (B).   A process for dyeing substrates that can be dyed with sulfur dyes, characterized in that the substrates are dyed with a leuco form of sulfur dyes (L) according to Claim 14 or 15.   A process according to claim 16, characterized in that the cellulosic textile material is dyed in an alkaline medium in the presence of a sulphide-free reducing agent, with subsequent oxidation. A process according to claim 16, characterized in that a pulp suspension is dyed with (L) and then treated with a tackifier and / or a flocculation agent, an agent   dewatering agent and / or a retention agent.   An aqueous concentrate composition containing (L) as defined in claim 14 or 15.   An aqueous composition according to the   19, characterized in that it also contains   a solubilising agent and / or anionic surfactant.   and / or a reduction stabilizer free of sulfide.