MXPA96001452A - Stable liquid suspensions and method to analyze mys - Google Patents

Abstract

The present invention relates to providing stable, pour-on aqueous suspensions of sulfur dyes, especially suspensions which are characterized by a very low content of inorganic sulphides and inorganic polysulfides. The suspensions are produced using certain suspension stabilizing agents consisting mainly of water-soluble polysaccharide gums, such as xanthan gum, whose solutions in water are pseudoplastic. The suspensions may additionally comprise a reducing agent other than sulfur and / or a dispersing agent. An improved method is also provided to determine the potential of such suspensions to release hydrogen sulfide upon acidification at a given temperature, which method comprises acidifying a sample of the suspension to pH 2.9-3.7, capturing or entrapping all of the hydrogen sulfide. released during acidification in an aqueous alkaline mixture and measuring the sulfur ion content of the aqueous alkaline suspension

Description

STABLE LYOTHT SUSPENSIONS AND METHOD TO ANALYZE IAS insuas. DESCRIPTION OF THE INVENTION The invention relates to stable (flowable) suspensions of finely divided particulate dyes or sulfuric (sulfur) dyes and with a useful method for determining their ability to emit hydrogen sulfide. In the textile dyeing technique it is often preferred to use products which are in the form of flowable (liquid) compositions. Such liquid compositions have certain advantages over powder or granular compositions. They are free of dust and are more suitable for use in automated equipment where they are pumped in dosed quantities from a storage or maintenance container to a dyeing apparatus. It is often desired that the successive charges be uniform. Therefore, it is important that each charge of a given flowable dye composition be of the same strength, so that consistent dyeings can be obtained during a given period of time during which several successive charges can be delivered from a given container. to a given dyeing apparatus. Therefore, in particular it is desirable that the flowable dye composition remain pumpable and easily agitable, so that uniformity can be restored, if necessary, when a load is to be delivered from the container to a dyeing apparatus. , for example an apparatus for textile dyeing. It is also desirable that the flowable composition (which can flow) be sufficiently stable so that it remains uniform during the period of its stay in the container. In the field of dyes or sulfur dyes (sulfur) the change from dry powders or granules to flowable compositions in the form of liquids, in particular for the dyeing of textiles, has been done for several years with the advent of sulfur coloring liquids (pre ) reduced, ie, aqueous solutions of sulfur dyes which are in (pre) reduced form (ie, leuco). Such liquids are often produced by heating the sulfur dye in an aqueous alkaline medium and invariably involve the presence of one or more inorganic sulfides, such as sodium sulfide and / or one or more inorganic sulphides. Such a compound can be obtained by a thionation reaction by which the sulfur dye is produced, or it can be generated in situ during the solubilization of said dye as a result of the reaction of the alkali on the unreacted sulfur of the reaction of tionation, which is present in the dye, or can be added to the aqueous alkaline medium as a reducing agent during the solubilization of the dye or, in small quantities for the purpose of avoiding premature reoxidation of leuco sulfur dye during transport or storage , or its presence may result from the combination of these factors. Aqueous suspensions of sulfur dyes can be produced in solid particulate form which are free of sulfur or the sulfur content is so low that they have little or no sulfur related hazard to humans or their environment. However, such compositions may be destabilized and / or the suspended dye may settle out by a prolonged standing time. It has been proposed to combine the insoluble dyes with substantial amounts of high molecular weight polymers, in particular polycarboxylates, aminoplast resin polycondensates or nonionic copolymers of > .65% ethylene oxide with an additional olefin oxide, optionally together with a minor proportion of xanthan gum, in order to produce stable aqueous dye suspensions. It has now been found that aqueous suspensions of sulfur dyes that do not contain large amounts of the above synthetic polymers or that preferably do not contain any such synthetic polymers, but that contain only a small proportion of a stabilizing agent in suspension (A) of Pseudoplastic rheology consisting mainly of a water soluble polysaccharide gum or a mixture thereof as defined above, have surprisingly good properties of stability and fluency. It has further been found that the inorganic sulfur content of such suspensions can be verified to a highly precise extent, so that it is possible to produce sulfur dye suspensions practically free of sulfur as described below, while reducing to a minimum the risk of over-acidification or over-oxidation-for the purpose of removing sulfur ions such as H2S or by oxidation, or by both methods. The invention relates to defined stabilized sulfur dye suspensions, their production and use, as well as to the analytical method for measuring the ability of the sulfur dye composition to release hydrogen sulfide upon acidification. Therefore, the invention provides a pourable suspension (S) of a sulfur dye or a mixture of sulfur dyes in an aqueous liquid containing a suspension stabilizing agent (A), aqueous solutions which exhibit a behavior pseudoplastic and consisting mainly of a water-soluble polysaccharide gum, in a concentration from 0.01 to 10% by weight, based on the weight of the suspension. By the term "pourable" is meant that the suspension (S) is flowable, ie, having a viscosity which allows it to flow freely from a container, preferably a viscosity not exceeding 10,000 centipoise (cP) ), more preferably not more than 5000 cP, more preferably not more than 4000 cP, especially not more than 3000 cP. Advantageously, a suspension (S) according to the invention will have a viscosity of at least 30 cP, preferably at least 100 cP, more preferably at least 250 cP, more preferably at least 300 cP, especially at least 400 cP. Sulfur dye suspensions (S) according to the invention having viscosities in the range of 250 to 2000 cP, especially 350 to 2000 cP, are particularly preferred. The viscosities established in the above are those determined in the known manner, at 25 ° C and 60 rpm using a Brookfield rotational viscometer, model LVT, with a rod or shaft # 3 for viscosities up to 2000 cP and a rod # 4 for viscosities greater than 2000 cP. Preferably, a suspension (S) according to the invention is one in which the distribution of the solid sulfur dye particles are throughout the liquid in substantially uniform forms. This means that any two equal volumetric portions of the suspensions which are extracted therefrom at the same time will contain substantially equal amounts, by weight, of solid particles. By "substantially equal amounts, by weight" is meant that the amounts, by weight, of the sulfur dye in their respective portions are sufficiently identical so that the two volumetric portions, when used separately for the purpose designed under identical conditions , will produce substantially identical results. For example, the two equal volumetric portions, when used in two identical, but separate, dyeing procedures, in particular textile dyeing processes, will produce dyeings of substantially equal dyeing strength, ie, within a + 5% sign, so preferable ± 3%, relative to one another, measured in the known manner using a spectrophotometer, such as the CS-5 model which, together with a set of appropriate computer programs, is available from Applied Color Systems, Incorporated. More preferably, the weights of the solid particulate material in each portion are, in themselves, within ± 5% of each other. Preferably, the uniformity described in the above is further applied to the distribution of the suspension stabilizing agent (A) which is described more fully below. The concentration of the solid particulate sulfur dye in the suspension may vary within very narrow limits, depending, for example, in addition to the designed use. For example, its concentration may be dictated in part by the desired tinting force of the suspension. In general, concentrations of 5% or more are contemplated, based on the total weight of the composition, with concentrations of 20% or more being preferred. The concentrations of the solid sulfur dye particles can be as high as 60%, with concentrations as high as 50% being preferred. Concentrations in the range of 10 to 45% by weight are especially suitable. The size of the solid particles may vary, depending on the additional characteristics of the suspension. They should not be so large that they are so large that they tend to settle out of suspension. Although such a trend can be suppressed to a significant extent by the use of a suspension stabilizing agent (A) as described in the following, the particles should not be so large as to require the presence of a suspension stabilizing agent in such a large amount. large that increases the viscosity of the suspension at a point where it can no longer be poured. In addition, the solid sulfur dye particles must be small enough to dissolve easily during the dyeing process. Suitable particle sizes can be determined and produced by a person ordinarily skilled in the art without undue experimentation. Preferably, at least 99%, ideally all of the particles are less than 400 μm (diameter), more preferably less than 200 μm, with particles smaller than 120 μm being preferred, with average particle diameters ( volume distribution) <; 50 μm being especially suitable. The particle size can be measured using a Microtrac II particle size distribution analyzer model # 7997-10 or # 7997-20, or by using a "Malvern Mastersizer" model MS1002 from Malvern Instruments, Malven, England. For many sulfur dyes a suitable particle size is often obtained directly from the thionation reaction or, if necessary, from a subsequent treatment in which the dye is precipitated from the thionation reaction mixture, as is described below, with little or no mechanical size reduction treatment. In other cases, a mechanical reduction of conventional size, such as ground, can be carried out, if necessary. Preferably, a composition (ie, a suspension) (S) according to the invention is stable insofar as it will retain the uniformity described above for a period of at least 24 hours. More preferably for at least two weeks, more preferably at least two months, even up to 6 months or more, by letting it stand at temperatures in the range of 2 to 35 ° C. Preferably, a composition (S) according to the invention is also stable against an irreversible change in viscosity for the times and under the conditions specified in the preceding paragraph. By "change in viscosity" is meant an increase that will return to the suspension incapable of being poured or a decrease that adversely affects the stable uniformity described above. More preferably, it means a change of more than 50%, measured in cP, as described above. By "irreversible" is meant a change which can not be reversed by agitation, pumping or some other method of agitation of the suspension. More preferably, the suspension (S) of the invention is stable against any change in viscosity, either reversible or irreversible, which renders it incapable of being poured or which substantially modifies the rate or flow rate, for example, in more than 50% or even, preferably, more than 20%. The aqueous liquid component of the suspension (S) is water or a mixture of water and an organic solvent, in which the material comprising the solid particulate material is insoluble or soluble to a degree no greater than about 20%, preferably not greater than 10%, more preferably not greater than 5%, more preferably not greater than 1%, by weight of the material, at 22 ° C at concentrations to which it must be present in the suspension. The liquid component is also one in which the suspension stabilizing agent (A) is soluble in the amounts used, in particular at temperatures in the range of 5 to 80 ° C, especially 10 to 50 ° C. Preferably, it is water or a mixture of water and not more than 60%, more preferably not more than about 20%, in particular, not more than 10% by weight of such a mixture, of an organic liquid miscible with water suitable, such as acetone or an aliphatic alcohol of 2 to 4 carbon atoms, in particular isopropanol, ethylene glycol, propylene glycol, diethylene glycol or glycerol. More preferably, the liquid component consists solely of water.

Advantageously, the sulfur dye or dye is sufficiently free of inorganic sulphides and polysulfides that an aqueous mixture of the dye, when acidified to pH 3 with phosphoric acid at 22 ° C, will generate no more hydrogen sulfide than it can produce a maximum of 1000 parts per million by weight of sulfur ion (S ~~) in an aqueous alkali, based on the weight of the dye, preferably no more hydrogen sulfide than that which can produce a maximum of 500 ppm, preferably a maximum of 250, more preferably 100 , especially 50 ppm by weight sulfur ion, based on the weight of the dye. Preferably, the sulfur dye is in the oxidized form. As used herein, the term "sulfur dye" is understood to include those dyes which are known as "sulfur dyes" or "sulphurized vat dyes" of VENKATARAMAN "The Chemistry of Synthetic Dyes" (" The chemistry of synthetic dyes ") Volume II, Chapters XXXV and XXXVI (1952) and Volume VII (1974), or as defined in the Color Index as" sulfur dyes "or as" vat dyes "with an indication of sulfurization in the method for its synthesis. The representative dyes are black 1 sulfur C.I., blue 7 and 13 sulfur C.I., red 10 and 14 sulfur C.I., green 2 and 16 sulfur C.I., brown 3, 37 and 96 sulfur C.I. and blue 43 from Cuba C.I. Of greater interest are those dyes which are known as "sulfur dyes" of the references mentioned above, particularly black 1 sulfur C.I. The particles of solid sulfur dye can be obtained from a thionation reaction which, in turn, can be obtained by a conventional ionization reaction. Such reactions are well known in the art for manufacturing sulfur dyes, as described in the references mentioned above. The particular thionation reaction used is not critical to this invention, but rather is dictated by the particular sulfur dye which it is desired to produce. Sulfur dyes which are characterized by the degree of freedom described above from inorganic sulphides and polysulfides can be produced in various ways. Preferably, the thionation reaction mass is oxidized. This has the effect of causing the dissolved sulfur dye which may be present in its (partially) reduced (ie, leuco) form in the thionation reaction mass to precipitate to convert such dye to its oxidized form insoluble in water and converting the inorganic sulphide and / or polysulfide salts present in the mass to thiosulfate salts. The oxidation can be carried out using various known electron acceptor substances or oxygen sources, for example, sodium nitrite, sodium sulfite, a peroxide (for example H202 or sodium peroxide), gaseous oxygen, air or oxygen mixed with air. Strong oxidizing agents (such as peroxides) can cause depolymerization of some suspension stabilizers, such as xanthan gum. This can be avoided either by not using an excess of such an oxidizing agent or by removing any excess of the dye before combining the dye with a suspension stabilizer or by not using a strong oxidizing agent. Preferably, the oxidation is carried out with moderate oxidizing agents (for example sodium nitrite, sodium sulfite or air), more preferably by aeration of an aqueous mixture of the crude thionation reaction product, for example, Bubbling air into the aqueous mixture while stirring. The rate of aeration is not critical, but preferably it must be such that it produces particles of the particle size described above or sufficiently close to such a particle size that mechanical reduction of excessive size is not required. Within the skills of the technique are determining the proper speed without undue experimentation. Satisfactory results can be obtained at an aeration rate of about 0.01 to 0.02 m 3 of air (particularly normal air) per minute per kilogram of total mass that is being aerated. During aeration, the temperature of the reaction mixture is often maintained in the range of 50 to 90, preferably 60 to 85 ° C. The pH may vary from 7 to 14, preferably from 9 to 12. The oxidation preferably continues until all the sulfur dye has precipitated. A convenient method to determine when this point has been reached is to carry out a spot test. According to this test, a representative sample of the resulting suspension is placed to form a spot on a P8 crepe filter paper at 40 ° C. The greater the proportion of dye that has precipitated, the greater the amount of dye solids in the center of the stain and the lower the amount of color in the stain dispersion. When all of the dye has precipitated, the center of the stain will contain the dye solids and the dispersion will be clear (preferably clear as water). The aeration time can vary considerably, depending on the particular dye, the rate of aeration and the amount of the thionation reaction product that is aerated. For some dyes, such as black 1 of sulfur CI, a significant proportion of the dye is dispersed from the solution at the end of the thionation reaction and aeration times of approximately 0.5 to 4 hours are sufficient to precipitate the rest, while Aeration times of up to 48 hours may be required for other dyes which dissolve more completely in the thionation reaction mixture. The aqueous suspension of water-insoluble sulfur dye particles prepared as described above can be used as such to produce a stable suspension (S) according to the invention. On the other hand, the solid dye can be separated from the original aqueous medium by conventional methods, for example, filtration and optionally washed, and subsequently produce a fresh suspension by mixing the filter cake with a fresh amount of water or a mixture of water and water. an organic liquid miscible in water as described above. This latter technique is preferred for black 1 of sulfur CI, and for any other of the sulfur dyes in which it is desired to decrease the salt content of the thionation product, ie, when the initial aqueous suspension may have a content of salt higher than desired It can also be used in cases where the initial suspension still contains part of the dissolved sulfur dye. Another method for obtaining the sulfur dye in a suitable state (preferably in particulate solid form) from the thionation reaction mixture is to add sufficient acid to the reaction mixture to cause the dissolved dye to be converted to a form insoluble in water and convert the inorganic sulphides and polysulfides which may be present, to hydrogen sulfide which can be separated from the dye by means of a washing apparatus. The acidification is preferably carried out at pH 5-6 using a strong acid, for example sulfuric or hydrochloric acid. The degree to which the dye has precipitated can be verified by using the stain test described above. The acidification can be carried out until the desired amount of dissolved dye has been converted to a water-insoluble form and the inorganic sulfur content of the resulting mixture has been sufficiently decreased and the resulting mixture can be used directly to form the final suspension or the acidified mixture may first be filtered and optionally washed, to separate the dye precipitate from any dye which has not precipitated and sulphides and / or inorganic polysulphides which may remain dissolved in the mixture, and the filter cake The resultant can then be mixed with a fresh supply of a suitable aqueous medium which can constitute the liquid component of the final suspension (S). If the dye sulfur occurs mainly in solid particulate form by the thionation reaction, the reaction mixture can be filtered and the filter cake and then be mixed with fresh aqueous liquid and oxidized or acidified to pH 5 to 6 , as necessary, to convert the inorganic sulfide and / or polysulfide salts, which may be present, to hydrogen sulphides, which may be extracted by known methods. The two methods can also be combined (ie, oxidation - in particular aeration - and acidification). Regardless of which of the above methods of treating the reaction mass thionation is carried out, an oxidation or sufficient acidification be carried out, optionally with sufficient removal of inorganic sulphides and / or inorganic polysulphides unconverted by filtration or decantation, of so that the solid particles of the sulfur dye that are present in the final suspension are free of such sulfides and polysulfides as described above. This can be determined by testing an aliquot portion of the liquid that contains the solid dye by acidifying it., for example at pH 3, with phosphoric acid at 22 ° C, which reacts all of the hydrogen sulfide produced by it in aqueous sodium hydroxide and measures the concentration of the sulfide ion in the resulting solution by ionic chromatography, as it is described more fully in the following. If the concentration of the sulfide ion is greater than 1000 ppm by weight, based on the weight of the dye, preferably greater than 50C ppm, more preferably if it is greater than 250 or even 100 ppm, it should be carried out Preferably an additional oxidation and / or acidification reaction and in addition preferably more liquid containing sulfur and / or inorganic polysulfide should be separated from the solid dye particles. The pH of the suspensions (S) can vary over a broad spectrum. It is preferred that the pH of the sulfur dye (S) slurries of the invention be in a range of weak acid to weak base, in particular in a pH range of 6 to 9. In this pH range, the product it is less corrosive and less dangerous than in the strongest acid or base ranges. The pH can be adjusted, as necessary, by the controlled addition of an effective amount of a suitable acid, such as acetic acid, phosphoric acid or, preferably, sulfuric acid to the liquid containing the sulfur dye. This can be done before or after the addition of the suspension stabilizing agent (A), but preferably it is carried out in advance. When the dye has been precipitated and the content of inorganic sulphides and polysulfides is adequately low, the water can be extracted from the aqueous dye mixture (for example, if the mixture has not been filtered) or can be added to the dye mixture. aqueous (for example, if the mixture has been filtered and optionally washed, and is in the form of a filter cake, for example filter-press cake), as necessary, to adjust the dyeing strength to a predetermined standard. This can be done before or after adding the suspension stabilizing agent (A). The suspension stabilizing agent (A) is characterized by its pseudoplastic behavior in aqueous solution and consists mainly of a water soluble polysaccharide gum, which has in particular the function of preventing a solid particulate sulfur dye, as described above, The suspension of the suspension in the aqueous liquid, as described above, for a period of time as described above without irreversibly increasing the viscosity of the suspension to the point where it can not be poured. Preferably, it is a polysaccharide gum which is effective to stabilize the substantially uniform distribution, as described above, of solid particulate sulfur dyes or dyes in the liquid without increasing the viscosity of the suspension, reversibly or irreversibly, until the point where it can not be poured. More preferably, it is a water soluble polysaccharide gum which is effective to stabilize the uniformity of the distribution of the solid sulfur dye particles in the aqueous liquid. If desired, the suspension stabilizing agent (A) may also contain a minor amount of an additional substance which is effective to prevent the solid particulate material, as described above, from settling and separating from the suspension in the suspension. an aqueous liquid, as described above, for a period of time as described above without the viscosity of the suspension being increased irreversibly to a point where it can not be poured. Preferably, it is a substance other than a polysaccharide gum, which also contributes to stabilizing the substantially uniform distribution, as described above, of solid particulate sulfur dyes or dyes in the liquid without increasing the viscosity of the suspension, reversible or irreversibly, even at a point where it can not be poured. More preferably, it is a water soluble substance which is effective to stabilize the uniformity of the distribution of the solid sulfur dye particles in the aqueous liquid. The fact that (A) consists mainly of a water-soluble polysaccharide gum means that the soluble polysaccharide gum: in water represents a major proportion, ie, >50% by weight, preferably > 80%, more preferably 100% by weight of (A). Preferred suspension stabilizing agents (A) are those substances which are effective to stabilize the uniformity of a suspension of a solid particulate material in an aqueous liquid, as described above, when present in an amount less than 10%, of preferably less than 5%, more preferably less than 1% and much more preferably less than 0.5%, by weight of the suspension. Thus most preferably, the stabilizing properties of the suspension (A) are related to their ability to increase the viscosity of an aqueous liquid in which is dissolved and, more particularly, the solutions of the polysaccharide gums (A) in water they are of pseudoplastic rheology or - more briefly - they are pseudoplastic. By "pseudoplastic" it is meant that the apparent viscosity of the solution progressively decreases as the solution is subjected to shear stress or shear stress increasing, in particular that the aqueous solution is substantially non-thixotropic. The viscosity begins almost instantaneously to return to its total magnitude to the extent that the shear stress is reduced to zero. The most preferred suspension stabilizing agents, such as xanthan gum, are also non-thixotropic under most conditions of use. By "non-thixotropic" is meant that an aqueous solution of such agent does not decrease in viscosity under constant shear stress over a period of time. Another preferred typical feature of the stabilizing polysaccharide gums (A) is that their solutions in an aqueous liquid are viscoelastic. Preferably the polysaccharides (A) are heteropolysaccharides. Among the rubbers (A) are preferred polysaccharide stabilizer microbial polysaccharides such as dextran, gellan gum, rhamsan gum, gum and xanthan gum puelano, the last two of which are preferred. Xanthan gum is described in the literature and it is mentioned that it has the following structural formula: where M is Na, K ol / 2Ca and n is approximately 2000. Xanthan gum is an exocellular heteropolysaccharide, which occurs naturally in plants belonging to the cabbage family and is produced commercially by fermentation submerged aerobic using the bacterium X? mthaponas caitpestris in a fermentation medium containing a carbohydrate (such as sugar) and nitrogen. A method for their production is described in U.S. Patent No. 3,427,226, the disclosure of which is incorporated herein by reference. The TSCA inventory of the Uited States Environmental Protection Agency (CAS # 11138-66-2) is found. Additional information about this product, including the formula above, is contained in the brochure entitled "XANTHAN GUM Natural biogum for scientific water control" ("RUBBER OF XANTANE, natural biogoma for scientific control of water"), fifth edition (1994) , distributed by Kelco (formerly a division of Merck &Co., Inc., and now a unit of Monsanto Company), the description of which is incorporated herein by reference. According to the invention, a stable suspension (S) can be prepared by mixing the suspension stabilizing agent (A), the solid particulate sulfur dye or dyes and the aqueous liquid. The solid particulate material and the aqueous liquid can be combined first and the stabilizing agent is added thereto, either the stabilizing agent and the aqueous liquid can be combined first and the solid particulate material is added thereto either the stabilizing agent and the stabilizing agent. Solid particulate material can be added to separate portions of the aqueous liquid, and the two aqueous mixtures are subsequently combined. The stabilizing agent (A) of the suspension can be added to an aqueous suspension of water insoluble or sparingly soluble sulfur dye particles, the suspension which has been produced as described above, or such a suspension or a filter cake of The sulfur dye particles can be added to a solution of the stabilizing agent. The components mentioned in the above of the suspension can be combined over a wide range of temperatures, for example, from 10 to 70 ° C, obtaining excellent results at a temperature similar to room temperature. Preferably, the suspension stabilizing agent (A) can be added to the aqueous suspension with stirring and at a rate such that lumping is prevented. This can be done by slowly introducing the stabilizing agent into the upper portion of a vortex created by stirring the aqueous suspension. A particularly suitable method for mixing the stabilizing agent with the aqueous suspension comprises using an apparatus of the type described on page 20 of the aforementioned brochure on xanthan gum. This apparatus comprises a. Mixing tank equipped with an agitator and located below a liquid supply line to which a mixing eductor and a funnel is attached. Before introducing the stabilizing agent (A), the mixing tank is filled with sufficient slurry of aqueous sulfur dye to cover the mixer blades of the agitator when the vortex is going to develop. The agitator is then turned on and started to supply a flow of aqueous liquid from the supply pipe within the eductor at a pressure of 3.5 to 7.0 kg / cm2 (50 to 100 psi) and the dry stabilizing agent (A) is poured into it. the funnel, which is attached to the upper part of the eductor. In this way a mixture of aqueous liquid and stabilizing agent (A) is introduced via the eductor, into the aqueous suspension which is already in the mixing tank. The resulting fluid is continuously stirred until the stabilizing agent (A) dissolves and the suspension (S) is formed. The amount of suspension stabilizing agent (A) may vary, depending on the specific nature of the solid particulate sulfur dye, the aqueous liquid and the stabilizing agent, and also on the concentration of the suspension. It is within the ability of the technique to determine an adequate amount for each situation. As indicated above, it must be such an amount as to stabilize the uniformity of the suspension without permanently increasing (i.e., irreversibly) its viscosity to a point where it can no longer be poured at 25 ° C, preferably without returning it. even temporarily (ie, reversibly) unable to be poured at 25 ° C. More preferably, it must be such as to cause the suspension to have a viscosity within the limits specified above, in centipoises. Preferably, this amount should be less than 5% (ie, from 0.01 to 5%), for example from 0.05 to 5%, more preferably less than 1%, by weight of the suspension, much more preferable less than 0.5%, for example from 0.1 to 0.4%. In order to avoid the formation of molds or bacteria over a prolonged period, it is often advantageous to add an effective amount of a biocide or preservative. The particular compound used will depend on the particular microorganisms on which protective action of the composition (S), the particular components of the suspension and the pH is desired. The Technical Bulletin DB-31 entitled "Preservatives for Kelco Polymers Used in Industrial Applications" ("Condoms for Kelco Polymers Used in Industrial Applications") by Kelco (1986), the description of which is incorporated herein by reference , list thirty-five representative condoms which have been used successfully with xanthan gum and among which a person skilled in the art can make an appropriate selection in undue experimentation. Among these are sodium dimethyldithiocarbamate (AQUATREAT DNM-30); or sodium phenylphenate (DO ICIDE-A); formaldehyde; 6-aceto-2,4-m-dioxane (GIV-GUARD DXN); dichlorophene (GIVAUDAN G-4); 2-hydroxypropyl methanethiol sulfonate (HPMTS-10); tributyltin oxide (INTERCIDE 340A); 5-chloro-2-methyl-4-isothiazolin-3-one plus 2-methyl-4-isothiazolin-3-one (KATHON WT); benzyl bromoacetate (MERBAC 35); potassium trichlorophenate (METASOL CP); N- [- (l-Nitroethyl) benzyl] ethylenediamine (METASOL J-26); methyl p-hydroxybenzoate (METHYL PARASEPT); 2-bromo-2-nitropropane-l, 3-diol (MYACIDE AS); hexachlorodimethyl sulfone (STAUFFER N-1386); 1,2-dibromo-2,4-dicyanobutane (TEKTAMER 38); and 2- [(hydroxymethyl) amino] ethanol (TROYSAN N-174). Advantageously, from about 0.05 to 0.40%, particularly from 0.15 to 0.35%, and especially from 0.25 to 0.35%, based on the total weight of the stabilized suspension, of PROXEL GXL liquids from ICI Americas, Specialty Chemicals Div can be used. ., a condom constituted by 19% of 1,2-benzisothiazolin-3-one, 5-8% of sodium hydroxide, 40-60% of dipropylene glycol and 10-40% of water. Other condoms may be used, for example those listed above, in equivalent quantities. A suspension (S) according to the invention may also contain a dispersing agent, preferably an anionic dispersing agent. For these suspensions (S) which contain a dispersing agent, quantities in the range from 0.5 to 15%, especially from 1 to 5% by weight of the suspension are preferred. A preferred anionic dispersing agent is the reaction product of lignin with disodium sulfite and formaldehyde (CAS # 105859-97-0) available as REAX 83A. For some dyes, such as blue 7 for sulfur CI, blue 43 for Cuba, red 10 for sulfur CI, coffee 96 for sulfur CI, and particularly black 1 for sulfur CI, stable suspensions can be produced in accordance with the invention which do not contain a dispersing agent. It is within the ability of the art to determine whether a suspension of a particular sulfur dye can benefit from the presence of such a dispersing agent. According to a further embodiment of the invention there is provided a suspension (S) of sulfur dye as described above which also contains a reducing reagent (R) different from sulfur for the sulfur dye. By "reducing agent other than sulfur" is meant a reducing agent which is neither sulfur nor a polysulfide. The reducing agent (R) different from particular sulfur, may vary depending on the particular sulfur dye which is used. Essentially, it must be one which does not have a reducing effect on the sulfur dye under the conditions to which the suspension is maintained before being used, but which is effective in reducing the same dye in an aqueous medium under conditions which are more favorable for such reduction. More particularly, the reducing agent (R) must be one which does not cause reduction to the dye at temperature and pH at which it is maintained before being used in a dyeing process, ie at a pH of 9 or less , especially in the range from 5 to 8, more especially from 6 to 7, and at a temperature below 60 ° C, especially below 45 ° C, but which does not cause reduction of the dye to a pH higher than 9.5, especially above 10, and at a temperature above 60 ° C, especially above 70 ° C. A reducing agent (R) is one which has the properties mentioned above and is a carbonyl compound, especially an aliphatic carbonyl compound which contains in the alpha position with respect to the carbonyl group an amino group which may be acetylated or, preferably, an hydroxy group or an etherified hydroxy group, for example a methoxy group. Of special interest are the aliphatic compounds with 3 to 6 carbon atoms, such as 1-hydroxyacetone, 1,3-dihydroxyacetone, 3-hydroxy-2-butanone, carbohydrates with 3 to 6 carbon atoms and their derivatives in which one or more of the hydroxy groups present are etherified with methyl or substituted with an amino or acetylamino group, in particular reducing sugars, for example aldo sugars and keto sugars, and their oligomers and / or deoxy derivatives and also their uronic acids. Preferred carbonyl compounds can be represented by the following formulas wherein one of Rx and R2 is hydrogen and the other is -OH, -OCH3 or -NH2, R3 is -CH3, -CH2OH, -CHO or -COOM ^ x is hydrogen or a cation and m is an integer of 1 to 5.

Advantageously, M x is a colorless cation, preferably an alkali metal cation, more preferably sodium. If in the formula (I), m is an integer from 2 to 5, the m symbols of t can have, independently, the same meaning or different meanings, and the m symbols of R2 can have, independently, the same meaning or different meanings. In formula (I), one of R and R2 is hydrogen and the other is preferably hydroxy, R3 preferably means -CH2OH or if m means from 2 to 5, also a carboxy group and m preferably means 3 or, more preferably, 4. If, in formula (II), m means 3, 4 or 5, the (m - 1) symbols of Rx can, independently, have the same meaning or different meanings and the (m - 1) symbols of R2 can , independently, have the same meaning or different meanings. In formula (II) one of the two symbols Rx and R2 means hydrogen and the other preferably means hydroxy. If in formula (II), m means 1, R 3 preferably denotes -CH 3 or -CH 2 OH; if in formula (II), m means 2, 3, 4 or 5, R3 preferably means -CH 2 OH. Of the compounds of formula (II), those in which m means 1, 3 or 4 are preferred. The monosaccharides of formula (I) and of formula (II) may also be in the form of pyranoside or furanoside and the uronic acids of Formula (I) and Formula (II) may also be in lactone form. Representative reducing sugars are, in particular, aldopentoses, especially arabinose, ribose and xylose and hexoses, especially glucose, fructose, mannose and galactose, as well as their deoxy, dideoxy and aminodeoxy derivatives. As the reducing agent (R) it is also possible to use oligosaccharides, in particular disaccharides, especially sucrose, lactose, maltose, melibiose and cellobiose, and trisaccharides, tetrasaccharides and pentasaccharides, especially melezitose and raffinose, as well as syrups such as corn syrup, syrup malt and melasas which contain reducing sugars. The most preferred reducing agents (R) are those which reduce the Fehling solution, particularly reducing sugars, for example d-glucose. The reducing agent (R) may interact to some extent with the suspension stabilizing agent (A) for its stabilizing effectiveness. If such an interaction leads to a diminished stabilizing effectiveness, it can be compensated by increasing the corresponding amount of (A). Preferably, the reducing agent (R) is one which does not interact with the stabilizing agent (A) of the suspension so that it does not excessively decrease its stabilizing effectiveness. This means that the reducing agent (R) is one whose presence in the suspension (S) does not need an increase of more than about 50% in the amount of stabilizing agent (A) required, based on the weight proportion of the stabilizing agent. (A) with respect to the total undissolved solids in the suspension (S), to provide the same stability as the non-increased amount that the same stabilizing agent provides to an otherwise identical suspension which contains the same total weight of solids not dissolved in the form of sulfur dye alone, and does not contain a reducing agent (R). More preferably, the reducing agent (R) is one which does not decrease the stabilizing effectiveness of the stabilizing agent (A) of the suspension, for example, it is one of the above aldoazúcares or oligosaccharides. It is within the usual practice of the art to perform this optimization without undue experimentation when comparing samples with and without the respective reducing agent. The amount of the reducing agent (R) in the suspension (S) can vary, depending on the particular combination of reducing agent and sulfur dye, the amount of sulfur dye and the purpose for which the reducing agent is added. An amount of reducing agent (R) which is effective to reduce the total sulfur dye with which it is combined in the suspension (S) with the corresponding leuco sulfur dye, when such combination is subjected to effective conditions, can be used. for such reduction, as described above, particularly in a dyeing bath. This option offers the advantage that the correct amount of reducing agent required is already present together with the dye or dye, so that the end user does not need to calculate, weigh and add the reducing agent separately. On the other hand, the reducing agent (R) may also be present in a smaller amount, which provides the advantage of decreasing the amount of reducing agent which must be added separately to a dyeing bath by the end user to effect the reduction of the total sulfur dye. Preferably, the amount of reducing agent (R) is in the range of 1 to 60%, more preferably 15 to 50%, more preferably 20 to 40% by weight of the suspension (S) . Preferably, the reducing agent (R) is completely dissolved in the suspension (S) at 25 ° C at the concentration at which it is present. However, a reducing agent (R) which is soluble under the conditions at which the reduction is carried out, but which does not dissolve or only partially dissolves in the suspension (S) under the conditions a which the suspension is maintained before being used in a dyeing process. In the latter situation, the reducing agent (R) must be one whose undissolved amount can also be kept uniformly distributed throughout the suspension (S) by the stabilizing agent (A) which, if desired, is it can be used in an increased amount, provided it does not cause me to vary the viscosity of the suspension (S) of the parameters described above. The reducing agent (R) can be mixed with the sulfur dye before, during or after the addition of the stabilizing agent (A) of the suspension. More particularly, the reducing agent (R) can be added to a slurry of sulfur dye containing stabilizer produced as described above, or a mixture of the reducing agent (R) and the stabilizing agent (A) can be mixed with the sulfur dye, or the reducing agent (R) can be mixed with an aqueous suspension of sulfur dye particles produced as described above and the stabilizing agent (A) of the suspension is subsequently added to the resulting mixture. Conveniently, the reducing agent (R) is premixed with part of the water which constitutes the aqueous phase of the suspension (S). It is considered that the use of preferred reducing agents described above, particularly a reducing sugar such as glucose, may provide the additional advantage of decreasing the need which may exist in certain situations for the above-described addition of a biocide or preservative. For example, the use of a reducing sugar in an amount of about 30% by weight of the suspension, can decrease the required amount of biocide or preservative by approximately 50% or more, while amounts of approximately 50% or more of reducing sugar , in weight of suspension could, in some cases, eliminate the need for a biocide or preservative when such a compound might be necessary in some other way. It will be appreciated that the results will vary, depending on the stabilizing agent (A) of particular suspension, the particular reducing agent (R) and the particular microorganisms against whose action the suspension (S) is to be protected. The stable sulfur dye suspensions (S) of the invention are distinguished by surprising stability and fluidity, even with small proportions of (A), such as = X of (A) with reference to the total weight of (S). Much lower contents of inorganic sulphides and inorganic polysulfides can be obtained by the production method described above, in particular with the help of the analytical verification described before sulfur ions. The process satisfies the same criteria for the sulfides as set forth above for the aqueous mixtures of solid sulfur dye particles from which they are produced, when tested in the same manner as described more fully below. Suspensions (S) which produce less than 50 ppm sulfide ion, based on the weight of the dye, can be obtained as a result of the oxidation or acidification of the dye before the addition of the suspension stabilizer, as described above, and / or as a result of further oxidation which may be carried out during or after the addition of the stabilizer (A). The suspensions (S) according to the invention are particularly suitable for use when a pourable, flowable and pourable composition is desired, particularly a composition in which a uniform distribution of the solid particulate sulfur dye is desired. discontinued. Sulfur dye suspensions (S) can be used to dye substrates that can be dyed with sulfur dyes, especially textile material, in particular cellulosic textile material such as cotton, using conventional dyeing methods per se for dyeing such substrates with sulfur dyes, in particular continuous dyeing or exhausting methods. More particularly, the dye is rendered substantive to the textile material by treatment with a suitable reducing agent in an aqueous alkaline medium and then oxidized back to its water-insoluble form once it has been uniformly applied to the textile material. Just as the very low sulfur content and the use of (A) -especially when (A) consists essentially of only a water-soluble polysaccharide gum of pseudoplastic rheology- the advantageous (S) suspensions of the invention are manufactured from the point in view of the environment, the use of these suspensions in a dyeing process in which only reducing agents that do not contain sulfur in an aqueous alkaline medium are used is also advantageous for the environment. Such a process is described in U.S. Patent No. 5,234,465, the disclosure of which is incorporated herein by reference. Another suitable method comprises carrying out dyeing using only reducing agents other than sulfur in an atmosphere with a decreased oxygen content, preferably one in which the oxygen content is not more than 12% by volume, more preferably not higher of 10% by volume, more preferably not more than 7% by volume. In addition to the sulfur-reducing agents described above, other reducing agents are thiourea dioxide, sodium hydrosulfide and thioglycolic acid. When the reducing sugar is used as the reducing agent, amounts in the range of 1 to 10 grams per liter are generally used, at temperatures in the range of 70 to 130 ° C and an alkaline pH. A decreased oxygen content of the atmosphere can be obtained by purging the dyeing apparatus with an inert gas, such as nitrogen. The dyeing apparatus is preferably a jet dyeing machine or a tub dyeing machine with nozzle. A vacuum pump can be connected to the dyeing apparatus to extract oxygen and establish a constant flow of inert gas from an inert gas supply. Another aspect of the invention is a method for determining the potential of a sulfur dye composition to release hydrogen sulfide when acidified. More particularly, it is a method for determining the potential of the amount of hydrogen sulfide that can be brought to acidification by a sulfur dye composition comprising material which forms hydrogen sulfide by reacting with an acid, especially a composition comprising sulfides inorganic and / or inorganic polysulfides. The purpose of this method, which is essentially a test method, is to enable a person skilled in the art to predict what is the maximum amount of hydrogen sulfide which would be released from a composition, particularly a sulfur dye composition containing sulfur and / or Inorganic polysulphide at a given temperature, in which it is acidified.

According to this method, an aliquot of the composition to be tested, in particular in the form of a solution or a dispersion or suspension of particles of sulfur dye in a liquid at a pre-established temperature are acidified to the extent that cause hydrogen sulfide gas to be generated, an inert gas is introduced into the liquid in an amount effective to remove the hydrogen sulfide gas from the liquid and place it in an aqueous solution of a known concentration of an alkaline compound which is reactive with hydrogen sulphide to form a water-soluble sulfide salt, the reaction of the alkaline compound with the hydrogen sulfide takes place and the sulfide ion content of the resulting solution is measured. The composition to be tested can be any sulfur dye composition such as an industrial waste or a sulfur dye, which also contains another material and in which the inorganic sulfide and / or inorganic polysulfide is present as an initial component. or as a pollutant. The "other material" itself may also be capable of forming hydrogen sulfide by acidification but, preferably, this will not be the case. The composition contains solid particles, any such particles in which the sulfide or polysulfide may be trapped preferably must be no larger than they would be in normal use, ie, no greater than would normally be at the time they were contact (for example, intentionally or accidentally) with an acid in a situation different from that which occurs during the test method of the invention, so that the test will provide a reliable indication of how much hydrogen sulfide gas can be released as a result of acidification in the other situation. More preferably, any solid particle is in finely divided form. More preferably, and particularly when the composition is a sulfur dye composition, the particle size is as specified above for the sulfur dye suspensions which constitute another aspect of the invention. The method of the invention is especially suitable for determining the amount of hydrogen sulfide that can be potentially released as a result of the acidification of a sulfur dye composition which contains inorganic sulphides and / or inorganic polysulfides. Such a composition can be one in which the sulfur dye is essentially in the form of a particulate solid, as in suspensions, and in the stable, pourable suspensions described above, or it can be a liquid composition of a sulfur dye ( ) reduced, soluble in water, that is, a leuco sulfur dye. By "inorganic sulphides and / or inorganic polysulfides" it is meant water-soluble salts, especially alkali metal, such as sodium sulfide and sodium polysulfide. In the following, for brevity, the term "(poly) inorganic sulfide" will be used to refer to inorganic sulphides and / or inorganic polysulfides, unless a differentiation between them is desired. The following description focuses on inorganic (poly) sulfides, but it will be understood that similar considerations apply to situations in which the composition to be tested is made up of another material which can generate hydrogen sulfide upon acidification. The liquid in which the acidification takes place can be any liquid in which the inorganic (poly) sulfide and the acid can react to form hydrogen sulfide. Preferably, it is an aqueous liquid, that is, water or a mixture of water with an amount of a water miscible liquid which does not interfere with the reaction, for example, as mentioned above. Preferably, it is water alone. The amount of liquid in which the acidification takes place will preferably be such that all of the accessible inorganic (poly) sulfide present in the amount of the composition is tested., so that it dissolves therein before beginning the acidification reaction. This is not essential, since the additional inorganic poly (sulfide) solution in the liquid can take place since the one already in solution is converted to hydrogen sulfide and removed or extracted from the liquid. More particularly, the amount of liquid is sufficient to further dissolve any other component of the composition which is soluble in the liquid. It has been found that for sulfur dye compositions, reliable results are obtained when the amount of liquid is such that the concentration of the dye is in the range of 0.1 to 2.0%. Preferably, the liquid contains an alkaline substance to provide a buffer for better pH control during acidification. The addition of sufficient sodium hydroxide to produce 0.05N NaOH solutions has been found satisfactory. The temperature of the liquid at the beginning of the acidification will be the temperature at which it is desired to know how much hydrogen sulfide can be released by acidification of another quantity of the same composition. The temperature can be any temperature which it is considered that another amount of the composition is likely to be found when acidified, for example, during storage, handling or actual use. The method of the invention can be carried out at various temperatures, preferably in the range of 15 to 65 ° C. Temperatures in this range of average environmental temperatures, for example 20 to 25 ° C, are more significant, because they are the temperatures at which accidental acidification can probably occur. Any acid which is capable of converting the available inorganic sulfur and the inorganic polysulfide present to hydrogen sulfide can be used. Preferably, an acid which is strong enough to maintain the acidification reaction mixture at the desired pH described above is used. In those situations where it is known that an inorganic polysulfide is not present, a wide range of acids can be used, including acetic acid, hydrochloric acid, methanesulfonic acid, sulfuric acid and phosphoric acid. Otherwise, it is preferred to use a stronger acid than acetic acid, such as methanesulfonic acid, hydrochloric acid, sulfuric acid or especially phosphoric acid, which, although they are strong enough to decompose the inorganic polysulfide, in the form of their partial salts of alkali metal establish an easier pH control. The amount of acid used must be that amount which converts the largest amount of inorganic (poly) sulfur to recoverable hydrogen sulfide. Care should be taken to avoid over-acidification which can cause protonation of hydrogen sulfide, making it more soluble in water and more difficult to recover. Preferably, an amount of acid is used such that it causes the liquid medium to have a pH in the range of 2.9 to 3.7, more preferably, 3.0 to 3.5 during acidification. Preferably, the rate of acid addition is controlled to maintain the pH so that it does not fall below 2.9. Any inert gas capable of acting as a carrier for the hydrogen sulfide gas can be used for the method of the invention. Helium and nitrogen are preferably considered, the latter being more preferred. Preferably, the inert gas should contain less than 20 parts per million (ppm) by volume of oxygen, more preferably less than 10 ppm, more preferably less than 5 ppm, especially less than 1 ppm. This can be carried out by pre-treating the gas in a commercially available oxygen extraction device, such as a SUPELCO oxygen trap, or by bubbling it through an aqueous solution of oxalic acid. You can start with a commercially available gas that is already low in oxygen (for example, about 20 ppm), such as ultra high purity nitrogen, and pretreat it as described above. Preferably, the rate of inert gas supply is such that a regular, positive flow is established without splashing. More preferably, it is in the range of 750 to 850 milliliters per minute, for example in a test sample of 235 ml. The flow rate can be verified in a conventional flow meter. Preferably, the entire system is saturated or purged with the pre-treated inert gas before acidification begins. The inert gas is allowed to flow through the system until the maximum amount of hydrogen sulfide has been cleared or removed from the container in which the acidification is to take place. Often it is sufficient to continue the flow for approximately 30 minutes after the acidification reaction has ended. The aqueous alkaline solution in which the hydrogen sulfide gas is washed by the inert gas can be a solution of any base which can react with the hydrogen sulfide to form a water-soluble sulfur salt without introducing ions which interfere with the subsequent analysis of the sulfur ion concentration. Preferably, the base is an alkali metal hydroxide such as potassium hydroxide or, more preferably, sodium hydroxide. This solution can be of a known volume and contain at least a stoichiometric amount of the base with respect to the amount of hydrogen sulfide. The atmosphere above the alkaline solution can be checked for the presence of hydrogen sulfide gas using lead acetate paper. If the test is positive, more base must be added to the solution or to a second solution of the base, which also has a known volume, which must be used to trap any excess of hydrogen sulfide which has not been captured in the first solution, and the test method must be repeated completely with a new quantity of composition to be tested. Preferably, the concentration of sodium hydroxide in the first solution is >.2% by weight; often this concentration is sufficient to trap all of the hydrogen sulfide of the sulfur dye compositions described above. When the hydrogen sulfide can be trapped as described above and is captured in the aqueous alkaline solution, the resulting solution is analyzed for the sulfide ion content using methods known in the art, such as titration with excess iodine followed by retrotitulation with sodium thiosulfate or, more preferably, by ion chromatography. The above method allows to check the (poly) sulfide content of a thionation mass before being processed to (S). Therefore, the invention further provides a process for the production of a suspension (S) as defined above, in which during the acidification and / or oxidation reaction, the (poly) sulfide content is verified by means of of the previous analytical method. In this way, the used amount of acid and / or oxidizing agent can be optimized to a minimum, so that over-acidification and / or over-oxidation can be avoided, insofar as no undesirable amounts of (poly) sulfide remain entrapped. or of H2S in (S) or, respectively, in (A). The following examples illustrate the invention. Unless stated otherwise, all parts and percentages are by weight, and all temperatures are in degrees Celsius. "C.I." means "color index" EXAMPLE 1 The reaction mixture obtained by a conventional thionation reaction to produce the black dye 1 of sulfur CI, is aerated at 65-75 ° C and pH 9.5 until the acidification of a sample of the resulting suspension at pH 3 with phosphoric acid at 22 ° C. ° C which generates enough hydrogen sulfide to produce, by dissolving in excess aqueous sodium hydroxide, less than 50 ppm sulfur ion, based on the weight of the dye. The aeration rate is approximately 15 m3 per minute per kilogram of thionation reaction mixture. The suspension is filtered, and 1.918 grams of the resulting filter-press cake, which has a solids content of 65.7%, is mixed with 1.082 grams of water, with stirring. 11.3 grams of 98% sulfuric acid are added to this mixture, so the pH is decreased from 8.9 to 7.5, and then 6 grams of xanthan gum are added slowly (KELZAN from Kelco, a unit of Monsanto Company), room temperature, to the upper portion of the vortex created by rapid agitation of the mixture. To the resulting suspension 750 grams of water are added to adjust the dyeing strength and an additional 1.5 grams of xanthan gum. The resulting product has a viscosity of 800 cP and, when acidified to pH 3 with phosphoric acid at 22 ° C, generates less hydrogen sulfide than can produce 50 ppm of sulfur ion in aqueous sodium hydroxide, as measured by ion chromatography .

EXAMPLE 2 To 300 grams of crude aqueous thionation reaction mixture for the blue sulfurized vat dye 43 of Cuba C., produced in a conventional manner, is added 300 grams of water and 15 grams of sodium nitrite. The resulting mixture is heated to reflux for about two hours until the spot test shows a clear run. The pH of the resulting suspension is adjusted to 7.5 with sulfuric acid and diluted with an additional 600 grams of water to adjust the dyeing strength. To the diluted product, 0.37% KELZAN xanthan gum, based on the total weight, is added at room temperature and with stirring. Analysis of the resulting suspension as described above, shows that less than 10 ppm sulfur ion, based on the weight of the dye. It is stable with respect to the uniform distribution of dye particles for more than two months.

EXAMPLE 3 In 6.475 grams of water, 8.725 grams of the filter-press cake of black dye 1 of sulfur C.I., produced as in example 1, but having a solids content of 66.2%, is stirred. After stirring for 10 minutes, the pH is adjusted to 7.25 with 130.5 grams of 98% sulfuric acid and then with 33.4 grams of KANZAN xanthan gum which are added with rapid stirring at room temperature for a period of 10 minutes. Stirring is continued for about an hour and then 2.255 grams of water are added with further stirring to adjust the strength of the dye. The resulting suspension has a viscosity of 482 cP and produces less than 50 ppm of sulfur ion, based on the weight of the dye, when tested as described above. For protection against degradation due to microorganisms, a condom can be added as described above.

EXAMPLE 4 Twelve grams of the product of Example 1 and 205 grams of water are mixed in a beaker. To this mixture is added 19 grams of 50% aqueous sodium hydroxide, followed by 20 ml of a 53% glucose solution in water and then 2.0 ml of mixed onophosphate and diphosphate esters of 2-ethylhexanol. This mixture is poured and passed through a pad drying apparatus, heated to 38 to 54 ° C and stirred for 10 minutes. A length of cotton fabric is impregnated with the heated dye liquor and then treated with steam for at least 60 seconds in a Greenville / Aztec steam boiler. The dried material is immediately washed in water for at least 30 seconds and then oxidized for at least 60 seconds at 60 ° C in a 2% aqueous solution of a 50:50 mixture of sodium bromate catalyzed with sodium vanadate (DYETONE) and glacial acetic acid, solution which also contains an effective amount of a sodium salt of an acrylic acid homopolymer (SANDOPURE RSK) as an anti-redeposition aid. It is then moistened in hot running water for at least 30 seconds and dried in a flat bed press.

EXAMPLE 5 A jet-drying machine is loaded with a cotton fabric that can be dried and with enough water to provide a liquor ratio of approximately 10: 1 and the contents are heated to 49 ° C. To the heated bath add 0.5 g / 1 of SULPHALOX 100 (aqueous alkaline solution of ethylenediamine-tetraacetic acid), 0.5 g / 1 of SODYECO defoamer DSV (patented mixture of petroleum products), 25 g / 1 of sodium sulfate, 5 g / 1 of soda ash, 5 g / 1 of caustic soda (50%) and 5 g / 1 of a mixture of 94.5% glucose, 5% reducing dispersing agent and 0.5% oil against dust. An amount of the product of example 1 sufficient to provide 16% dye based on the weight of the textile material is gradually added over 5 minutes and the resulting mixture is heated to 7 ° C at a rate of 2.75 ° C / minute, while the atmosphere above the liquor in the apparatus is kept purged with nitrogen. The resulting dye bath is then heated to 93 ° C at a rate of 2.75 ° C / minute, and maintained at that temperature for 45 minutes. Subsequently the dyeing bath is cooled to 71 ° C and the content is wetted by overflow with subheated water until the bath water is clear. The liquor / goods ratio is readjusted to 10: 1 and the bath is heated to 49 ° C while the interior of the appliance is aerated. Two g / l of acetic acid (56%) and 2 g / l of DYETONE (12% aqueous sodium bromate solution / 1% sodium vanadate) are added and the resulting oxidation bath is heated to 65 ° C. and it is kept at that temperature for 10 minutes. The bath is then wetted by overflow and drained, and the apparatus is refilled with water to which 1 g / 1 of soda ash has been added. The dried textile material is then cleaned in the resulting liquor for 10 minutes at 88 ° C. Afterwards the bath is cooled to 71 ° C and the dyed material is removed from it.

EXAMPLE 6 In a solution < When prepared by mixing 176 g of water and 150 g of d-glucose, 174 g of filter cake / black 1 press of sulfur CI, prepared as in example 1, but containing about 70% by weight of solids and 30% water. The pH of the resulting suspension is adjusted to 7-7.5 with 1.1 g of 98% sulfuric acid and then 2.0 g of KANZAN xanthan gum are added thereto. The resulting suspension has a viscosity of 560 cP measured with a Brookfield rotational viscometer with a # 3 rod at 60 rpm.

EXAMPLE 7 a) Generation of Hydrogen Sulfide and Isolation of Sulfur Ions A 250 ml three-neck flask with 24/40 gaskets containing a magnetic stir bar is held over a magnetic stirrer. A pH electrode is placed, which is attached to a calibrated pH meter (with an adapter) in the center neck, and a 60 ml granulated addition funnel with pressure equalizer is placed in one of the necks, and a Purge tube with a gas inlet / outlet adapter is placed in the other neck. The nitrogen gas regulator outlet attached to an ultra-high purity nitrogen source is connected to a Kings Instrument Inc. Flow Meter flow meter (470 to 940 ml / min) with 3.4 mm (1/4 inch) Tygon tubing and from here to a 250 ml gas wash bottle with a fritted glass diffuser that is used as an oxygen trap. Lt Tygon tubing of the oxygen trap is separated with a "T" connector from which one branch is connected to the purge tube of the three-neck flask and the other branch is equipped with a clamp to suspend the flow of nitrogen, the which is connected to a graduated addition funnel. The output of the adapter with the tube < ie purge of the three-necked flask is connected by means of Tygon tubing to the purge tube of another 250 ml gas wash bottle with a fritted glass diffuser, which serves as a hydrogen sulfide trap, and the outlet of The hydrogen sulfide trap is connected to a fan. All connections are sealed with suitable fasteners, such as Keck fasteners on all 24/40 joints, and moistened lead acetate paper tapes are placed on all joints to detect any leakage of hydrogen sulfide. Dissolve one gram of oxalic acid with abundant mixing in 100 grams of deionized water and 100 ml of this solution is placed in the oxygen trap. A small magnetic stir bar, 50.0 ml of 4% aqueous sodium hydroxide, which was produced by mixing 40 grams of sodium hydroxide grit with 960 grams of deionized water and allowing it to be purged for 30 minutes with nitrogen, and 50.0 ml of deionized water are placed in the bottle that serves as a hydrogen sulfide trap, the upper part of the diffuser tube is joined and the bottle is placed on a magnetic stirrer. Half a gram is placed (± 0.1 mg) of the product of example 3 in the three neck flask. A mixture of 5 ml of 4% aqueous sodium hydroxide and 170 ml of deionized water purged with nitrogen is introduced into the three-necked flask. 60 ml of an 8.5% phosphoric acid solution prepared by mixing 100 grams of 85% phosphoric acid with 900 ml of deionized water is added to the graduated addition funnel in the side neck of the three-necked flask and then the funnel is added. wash for approximately 10 seconds with the pretreated nitrogen when opening the clamp of the Tygon pipe attached to it. The clamp is then tightened, so that the nitrogen flows only through the purge tube on the other side of the neck of the three-necked flask. The magnetic stirrers are activated and the flow of nitrogen is started at a rate such that there is no splashing of the contents of the containers comprising the apparatus described above, preferably about 770 mi per minute. The dropwise addition of the phosphoric acid solution then begins at a rate of about 10 ml per minute. When the pH of the acidification reaction mixture has decreased to about 4, the addition is continued at a slower rate until the pH is in the range of 2.97 to 3.03. At this point, the addition of acid is suspended and re-added only when it is necessary to return the pH to the indicated range from a higher pH which develops as the acid reacts. When the pH is stabilized in the range of 2.97 to 3.03, the addition of acid is completed, but the flow of nitrogen is continued for an additional 30 minutes, during which time the reaction is finished and all hydrogen sulfide generated should to be washed in the bottle that serves as a hydrogen sulfide trap and contains the 100 ml of sodium hydroxide solution.

Then, the hydrogen sulfide content in the trap is analyzed by ion chromatography to determine the sulfide ion content. b) Determination of the Concentration of Ton Sul furo by Ion Chromatography Instrumentation: Dionex 450Oi chromatograph equipped with a gradient eie pump, amperometric pulse detector and an AI450 data station.

Instrumentation Parameters: Column: Column Dionex IonPac HPIC-AS7 together with an AG7 protection column; Eluent: 100% sodium acetate 0.5 M, 0.1 M sodium hydroxide (C02 free), 0.5% (v / v) ethylene diamine (99%) in deionized water purged with helium; Flow rate: 1.0 mi per minute; Detector: Pulse amperometric detector with silver electrode at zero voltage; 50 μl circuit; Injection: Temperature: environment.

Sample preparation: In a 100 ml volumetric flask, 0.01 grams (± 0.01 mg) of the sulfur-containing solution of part (a) of this example is diluted with 10 ml of 0.1 sodium hydroxide solution. N prepared by dissolving 8.0 grams of 50% NaOH (w / w) free of CO2 in 1 liter of deionized water purged with helium.

Standard Preparation: In a volumetric flask, 7.5 mg (± 0.01 mg) of sodium sulfide nonahydrate (98% ACS grade) is diluted in 100 ml of 1 N sodium hydroxide purged with helium and 0.5 ml of this solution is diluted 10 ml with 0.1 N sodium hydroxide prepared as described above. Three portions of this standard are analyzed to obtain an average response factor before analyzing the sample. The ion chromatography system is purged with helium for at least one hour to exclude the presence of carbon dioxide. The ion chromatography of the sample is carried out and the amount of sulfide ion is calculated according to the equation: Concentration of sulfur ion in the sample * x 1,000,000 Concentration of S ~~ (ppm) Concentration of the sample ** * weight of the sulfur ion in 100 ml of the NaOH solution ** weight of the dye suspension (ie, 0.5 g) in 100 ml of the NaOH solution.

It is determined that the suspension produced according to Example 3 generates an amount of hydrogen sulphide which produces less than 10 ppm sulfur ion according to this test method. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (28)

1. Unasuspension (S), which can be reversed, sulfur-bleached or sulfur-dyeing a mixture of sulphurous colorants and sulfur-based liquids, suspension which is characterized in that it contains an agent (A) suspension stabilizer, aqueous solutions which exhibit a pseudoplastic behavior and consist essentially of a water-soluble polysaccharide gum in a concentration from 0.01 to 10% by weight, with reference to the weight of the suspension.

2. The suspension (S) according to claim 1, characterized in that (A) is present in an amount effective to maintain a uniform distribution of the solid particulate material in the suspension for a period of at least 24 hours.

3. The suspension (S) according to claim 1, characterized in that the distribution of solid particles is uniform for at least two months.

4. The suspension (S) according to claim 1, characterized in that it has a viscosity not higher than 5000 cP.

5. The suspension (S) according to claim 3, characterized in that it has a viscosity in the range of 3000 to 4000 cP.

6. The suspension (S) according to claim 1, characterized in that it is stable for at least two months against an irreversible change in viscosity, which renders it incapable of being poured.

7. The suspension (S) according to claim 6, characterized in that it is stable against a change in viscosity of more than 50%, measured in centipoise.

8. The suspension (S) according to claim 1, characterized in that the concentration of the suspension stabilizing agent (A) is less than 5% by weight of the suspension.

9. The suspension (S) according to claim 7, characterized in that the concentration of the stabilizing agent (A) of the suspension is less than 1% by weight.

10. The suspension (S) according to claim 1, characterized in that the agent (A) stabilizing the suspension is substantially non-thixotropic.

11. The suspension (S) according to any of claims 1 to 10, characterized in that the polysaccharide (A) is a heteropolysaccharide.

12. The suspension (S) according to any of claims 1 to 11, characterized in that the suspension stabilizing agent (A) is a microbial polysaccharide gum.

13. The suspension (S) according to claim 12, characterized in that the stabilizing agent (A) of the suspension is a welano gum or xanthan gum.

14. The suspension (S) according to any of claims 1 to 13, characterized in that the sulfur binder or sulfur sulfur is black 1 sulfur C.

15. The suspension (S) according to any of claims 1 to 14, characterized in that upon acidification to pH 3 with phosphoric acid at 22 ° C, it will generate hydrogen sulfide no greater than that which can react with aqueous sodium hydroxide to form 500 parts per million sulfur ion, S "~, based on the weight of the sulfur dye.

16. The suspension (S) according to claim 15, characterized in that, upon acidification to pH 3 with phosphoric acid at 22 ° C, it will generate hydrogen sulfide no greater than that which can react with aqueous sodium hydroxide to form 50 parts per million of Sulfide ion, S "~, based on the weight of the sulfur dye.

17. The suspension (S) according to any of claims 1 to 16, further characterized in that it comprises a reducing agent (R) different from sulfur.

18. The suspension (S) according to any of claims 1 to 17, characterized in that it also contains a dispersing agent.

19. The suspension (S) according to claim 14, characterized in that it does not contain dispersing agent.

20. A process for the production of a suspension (S) according to any of claims 1 to 19, which is characterized in that it comprises combining an aqueous liquid, a solid particulate sulfur dye or a mixture of sulfur dyes which are insoluble or sparingly soluble in the liquid, and an effective amount of a suspension stabilizing agent (A), which is soluble in the aqueous liquid and optionally a reducing agent (R) different from sulfur and / or a dispersing agent.

21. The process according to claim 20, characterized in that the solid particulate sulfur dye or the mixture of sulfur dyes is in the form of a thionation mass, which optionally has been acidified and / or oxidized and / or optionally has undergone mechanical reduction of particle size and filtered and optionally washed.

22. The process according to claim 21, characterized in that the solid particulate sulfur dye or mixture of sulfur dyes is in the form of a thionation mass, which has not been subjected to a mechanical reduction in particle size.

23. He . process according to claim 20 to 22, characterized in that the thionation mass is oxidized and / or acidified in order to eliminate altering amounts of (poly) sulfide ions.

24. The process according to any of claims 20 to 23 characterized in that the sulfur dye which is sufficiently free of inorganic sulphides and inorganic polysulfides compared to an aqueous suspension thereof, when acidified to pH 3 with phosphoric acid at 22 °. C, will generate hydrogen sulfide no greater than that which can be produced by the reaction with aqueous sodium hydroxide, 100 parts per million sulfur ion, based on the weight of the dye.

25. A method for measuring the ability of a sulfur dye composition to generate hydrogen sulfide by being acidified at a given temperature, characterized in that it comprises acidifying an aqueous liquid containing a sample of the composition at a given temperature to a pH in the range from 2.9 to 3.7 with an acid which is strong enough to substantially convert all of the accessible inorganic sulfides and inorganic polysulfides present in the sample to hydrogen sulfide, wash the acidification reaction mixture with an inert gas amount effective to substantially remove all of the hydrogen sulfide therefrom, collect substantially all of the hydrogen sulfide from the acidification reaction mixture in an aqueous alkaline solution and measure the amount of sulfide ion in the alkaline solution.

26. The process according to claim 23, for the production of a suspension (S) according to any of claims 1 to 19, characterized in that during the acidification and / or oxidation of the thionation mass, the content of ( poly) sulfide by means of an analytical method defined in accordance with claim 25.

27. A process for dyeing or staining a substrate dyeable with sulfur dyes, wherein the sulfur dye is used in the form of a suspension according to any of claims 1 to 19.

28. The process according to claim 27, characterized in that it is used for the dyeing of cellulosic textile material.