US2267609A - Vat dye composition - Google Patents

Description

Patented Dec. 23, 1941 UNITED STATE S PATENT OFFICE vA'r DYE COMPOSITION Jean G. Kern, Buffalo, N. Y., assignor to National Aniline & Chemical Company, Inc., New York, N. Y., a corporation of New York No Drawing. Application January 28, 1939,

Serial No. 253,345

further treatment to fix the dye. In general, vat

15 Claims.

In the art of dyeing with vat dyes, two general methods are ordinarily employed. In accordance with one method, a vat comprising an alkaline solution of a reduced vat dye is prepared and the fibrous material to be dyed is worked in this solution whereby the fiber takes up the reduced compound of the dye. The material is then subjected to oxidation and other finishing treatments to convert the vat dye from the reduced to the unreduced form and further complete the fixing of the dye and finishing of the material. In accordance with the other method the dye is applied to the material to be dyed while in the unreduced form; it is then subjected to a reducing treatment whereby the dye is converted to the soluble form in the presence of the fiber and is then taken up by the fiber. It is then subjected to oxidation and/or other finishing treatments tofix the dye on the fiber, remove undesired residual material, and complete th'e finishing of the material.

In dyeing with vat dyes by the latter method, one of two procedures is usually followed, depending upon whether the material is to be dyed a solid color or with a pattern in one or more colors. If the material is to be dyed a solid color, the pigment padding (pad and jig) process is ordinarily employed, and if the material is to be dyed with a pattern, the printing process is generally utilized,

dye printing pastes, in addition to the unreduced vat dye, contain substances which in themselves do not reduce the vat dye under the conditions of the printing operation but which in subsequent operations react with the dye to convert it to the soluble form (such as sodium formaldehydesulfoxylate and potassium carbonate), other substances or assistants which pro mote the reduction of the dye and/or absorption of the reduced compound by the fiber, and suitable gums or thickeners. The fixing treatment usually comprises subjecting the printed fabric to a so-called steaming or ageing" In the pigment padding process, the unreduced vat dye in finely-divided form is suspended in a suitable suspension medium, usually water containing added materials such as thickeners and alkaline substances. The material to be dyed is passed th'rough this suspension, the fiber mechanically picks up the particles of insoluble dye, and the material is subsequently worked in a reducing bath whereby the dye is reduced to the soluble form and is absorbed and/or adsorbed by the fiber. The material is finally subjected to oxidation and finishing treatments to reconvert the dye to the insoluble form, fix it on the fiber, and further complete the finishing of the material.

The printing process of dyeing a textile fabric generally involves applying a so-called printing paste to the fabric in the form of a design (e. g., by meansof a screen, a stencil, or an engraved roll), and then subjecting the printed fabric to the pigment padding or printing processes, the

success of the operation is in a large measure dependent upon the uniformity with which the vat dye (e. g., the unreduced vat dye) is applied to the fabric. The vat dyes in unreduced form, as is well known, are insoluble in water and are not readily wetted by water. In preparing a padding bath or printing paste it is important that the vat dye be in finely-divided form, that it be uniformly distributed throughout the bath or paste, and in condition such that it may be taken up by the fiber. Further, it is important that the vat dye be capable of rapid and substantially complete reduction to the reduced form. The vat dyes, especially those which are intended for use in the pigment padding and printing processes, are generally marketed in the form of so-called dye pastes or color pastes, and dye powders. A dye paste of this kind is usually an aqueous mixture or suspension of finely-divided vat dye, which generally makes up 10 to 20 per cent of the paste. The paste usually contains a small amount of a dispersing agent such as Leukanol (a condensation product of femaldehyde and a naphthalene sulfonic acid) and the remainder is mainly water, a part of which is sometimes replaced by other liquids such as amino alcohols, polyhydroxy alkyl ethers or other polyhydroxy alkyl compounds, and cyclic ethers; as, for example, glycol ethers, glycol, glycerine, poly-glycerines, poly-glycols', .etc. These vat dye pastes are ordinarily produced by stirring the dispersing and other agents with the filter cake of the dye resulting from filtration of a precipitate of the dye obtained in its manufacture, or by precipitation in the finelydiivided form from a vat or sulfuric acid or other solution.

As noted above. vat dyes for use in the preparation of padding baths and printing paste may be supplied in the form of vat dye powders. In the case of the powders, it is important that the vat dyes contained therein not only have the properties pointed out above in connection with the vat dye pastes, but also that the powders be rapidly converted to uniform suspensions of the vat dye. Especially successful vat dye powders are described in my United States Patents Nos. 2,067,926 and 2,145,193. These vat dye powders are prepared by incorporating with the usual vat dye paste, e. g., one containing a small amount of a dispersing agent) a soluble salt of an acid alkyl ester of an oxygen-containing polybasic inorganic acid (e. g., a soluble salt of the sulfuric acid ester of a lower aliphatic alcohol) and preferably also an added substance such as, for example, dextrine, sugar, gum arabic, and the like, and then drying and grinding the resulting composition.

It is the principal object of the present invention to provide vat dye compositions which are productive of excellent dyeings and printings when employed in the usual ways. Another object of the invention is to provide vat dye pastes and powders which are adapted for use in the ei ilcient preparation of padding baths and printing pastes containing uniformly distributed therethrough the finely-divided particles of the vat dves. Another object of the invention is to provide vat dye pastes and powders which when used in the preparation of padding baths and printing pastes are productive of compositions characterized by the marked efficiency with which the dye is initially taken up by the fiber and the increased brilliancy andstrength of the resulting dyeings and printings as compared with the dveings and printings obtained by the use of padd ng baths and printing pastes prepared from ordinarv vat dye pastes. A further object of the invention is to provide vat dye pastes which remain fluid on standing and which may be easily and quickly mixed with the ingredients making up the conventional padding baths and printing pastes to form homogeneous compositions containing the vat dyes in well-dispersed condition.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The vat dye compositions of the present invention consist essentially of a vat dye compound in the unreduced or other form and a soluble organic ester of a saturated aliphatic mono-carboxylic acid containing not more than 8 aliphatic carbon atoms joined carbon to carbon. The esters that have been found to be adapted for use in the compositions of the invention contain at least one sulfate, sulfonate, or phosphate group, and their ester groups are free from aliphatic radicals containing more than a total of 12 aliphatic carbon atoms per aliphatic radical and from straight carbon chains of more than 8 aliphatic carbon atoms. In speaking of soluble esters it is meant esters that are soluble in water and or in alkaline solutions. The invention is based upon the discovery that esters of this class possess a combi nation of properties which make them valuable for use in compositions containing vat dyes, and

especially in vat dye compositions in paste or powder form intended for use in the preparation of padding baths or printing pastes.

In preparing a vat dye paste in accordance with the present invention, a vat dye, usually in the form of a press cake (a mixture of a vat dye in finely-divided form with water as obtained in the course of manufacture of the dye) is mixed with an ester of the above class and also preferably with a dispersing agent (for example, Leukanol or sulfite waste liquor).

The resulting mixture isthen diluted with water to the desired dye-strength; or if the paste is to be a so-called non-drying paste, that is to say, one in which the water is replaced in whole or part by a water-miscible, high-boiling alcohol such as isobutyl alcohol, glycerine, glycol, polyglycerines, polyglycols, and alkyl ethers of these compounds, the requisite amount of such alcohol is added to the mixture and water is removed therefrom by evaporation until the paste has the desired dye strength. The compositions prepared in this way comprise fluid pastes consisting of dispersions of the finely-divided vat dye. The compositions are relatively stable and do not settle on standing over a relatively long period of time. Furthermore, as compared with many available vat dye pastes, they are in a fluid or free-running state. Thus they are adapted to be efliciently and quickly incorporated with the other ingredients of padding baths and printing pastes to prepare such baths and pastes in a form such that the resulting compositions may be emciently employed in dyeing and printing.

When preparing the vat dye compositions of the present invention in the form of vat dye flakes, scales, grains, powders, and the like, the pastes prepared as described above, but usually with little or no high-boiling water-miscible alcohol therein, may be concentrated and or dried, as by means of a vacuum or atmospheric rotary drum drier, by spray drying, or by means of the addition to the paste of an anhydrous hydrate-forming inorganic salt. It is preferable, however, when preparing the powders to add to the paste before drying a substance such as sugar, dextrine, gum or starch, or derivatives of alginic acids and/or other suitable additions. In preparing the dry products employing a mechanical drier, the dry product scraped from the drier is in the form of flakes,'scales or grains, and may be used as such, but may also be ground to produce a finely-divided powder.

The esters employed in the vat dye compositions of the present invention are such as are derivable from any saturated aliphatic monocarboxylic acid containing less than 9 carbon atoms (such as, for example, acetic acid, propionic acid, normal and isobutyric acids, normal and isocaproic acids, normal and isovaleric acids, normal and isoheptylic acids, caprylic acid, their isomeric acids, etc.), and an organic hydroxy compound, especially an alcohol, containing not more than Baliphatic carbon atoms in a straight carbon chain and a total of not more than 12 aliphatic carbon atoms. The aliphatic monocarboxylic acids from which the esters are derivable may contain substituents; such as, for example, halogens, hydroxy], amino, and aromatic radicals.

The said esters may be derivatives of openchain aliphatic monohydric or polyhydric alcohols, or of monoor polyhydric hydroaromatic alcohols, cycloaliphatic alcohols, heterocyclic alcohols, aralkyl alcohols, mixed aliphatichydroaromatic alcohols, or of monoand polyhydric alcohol ethers. As examples of such alcohols there may be mentioned ethyl, propyl, allyl, butyl, amyl, hexyl, heptyl, octyl, and the like alcohols; cyclohexanol, methyl cyclohexanol, cyclopentanol, tetrahydrofurfuryl alcohol, benzyl 2,261,609 alcohol, phenyl ethyl alcohol, phenyl, methylcarbinol, the various terpene alcohols; ethylene, propylene, di-ethylene, and triethylene glycols, and the like; and the methyl and ethyl ethers of ethylene, di-ethylene, or other glycols. As typical alcohols there may .be also mentioned the following alcohols which are obtainable as by-products in the production of methanol by the catalytic hydrogenation of mixtures of carbon monoxide and carbon dioxide: a-methyll-pentanol; '2-methyl-1-pentanol; 2,4-dimethyll-pentanol; 3-methyl-2-pentanol; 2,4-dimethylare particularly valuable for use in the vat dye compositions.

Where the appended claims an ester of an alcohol and an aliphatic monocarboxylic acid is referred to it will be understood that an ester derivable from an alcohol selected from any of the above described classes and an aliphatic monocarboxylic acid is intended, unless otherwise indicated.

It will be understood that the alcohols from which the esters are derivable may contain substituents which do not alter the essential physical or chemical characteristics of the esters. As indicated above, polyhydric alcohols may be employed and in this case either one or both of the hydroxyl groups may be esteriiied with the carboxylic acid group of the acid employed. When only one of the hydroxyl groups is esterifled, one or more free hydroxyl groups remain, which are not objectionable and in some cases appear to have an advantageous effect upon the properties of the esters. The amino group may also be mentioned as an example of a substituent which may be present in the alcohol residue of the esters, valuable esters adapted for use in the vat dye compositions being derivable from amino alcohols.

It has been found that the best results are obtained with esters of the above class which contain sulfonate and/or sulfate groups and which display high solubility in aqueous solutions and/or alkaline printing pastes. ingly, the preferred esters are those which are derived from lower aliphatic alcohols (l. e., containing 2 to 6 carbon atoms), cycloalkyl alcohols, and aromatic alcohols. It has been found that esters which are derivatives of isobutyl alcohol are of markedly high value. For similar reasons, the esters derived from the shorter chainlength aliphatic monocarboxylic acids (i. e., containing 2 to 4 carbon atoms) are of particular value. Acetic acid is preferred as the aliphatic monocarboxylic acid. While preferred esters contain one or more sulfonate and/or sulfate groups, it has been found that those esters which contain at least one sulfonate group ar especially valuable. Further, although the solubilizing group of the sulfonated and/or sulfated esters may be in the ester radical, the acyl radical, or both, it is preferred to employ such esters in which the solubilizing group, preferably a Accordethane sulionate group, is in the acyl radical and the ester radical is free from solubilizing groups.

- view of the foregoing disclosure, it will be rea ly apparent that a large number of esters are available for use in the compositions of the invention. The following esters (described in the form of the free acids of the inorganic acidresidues contained therein) are given as examples of typical esters of the class hereinabove disclosed: isobutyl sulfoacetate; n-amyl-betasulfo-beta-furylpropionate; n-amyl sulfoacetate; isobutyl sulfatobutyrate; isobutyl phosphatobutyrate; C-phenyl-isobutyl sulfopropionate; normal-hexyl sulfoacetate; cyclohexyl-sulfoacetate; normal-amyl sulfatobutyrate; 4-methyl1- pentyl sulfoacetate; isobutyl sulfobutyrate; 2- methyl-l-pentyl sulfobutyrate; 2,4-dimethyl-1- pentyl sulfoacetate; tri-isopropylcarbinol sulfoacetate; glyceryl-di-(sulfoacetate) 4-methyl-1- hexyl sulfoacetate; monoethyl-ether of triethylene glycol sulfoacetate; triethylene glycol sulfoacetate; triethylene glycol sulfatoacetate; mono-acetylglycerine sulfoacetate; methyl-cyclohexyl sulfoacetate; tetrahydroiurfuryl sulfobutyrate; tetra-hydrofuriuryl-aminoethyl sulfoacetate; phenyl-methyl-carbinol sulfoacetate; secondary octyl sulfoacetate; octyl sulfoacetate; thesulfuric acid esters or phosphoric acid esters of the glyceryl esters of acetic acid; the glyceryl esters of glycollic or lactic acid which are "sulfated or phosphated in the glyceryl radicals;

the sulfoethyl ester of beta-hydroxyethylamidopropionic acid (the sulfoethyl ester of N-hydroxyethyl succinamic acid); sulfatopropyleneglycol acetate; sulfatoethyleneglycol butyrate; and the monosulfate of glycerine monosulfoacetate.

The esters employed in the present invention may be prepared in any well-known or suitable manner. For example, the sulfated esters may be prepared by reacting the ester of the corresponding unsaturated aliphatic acid with concentrated sulfuric acid or the ester of the corresponding hydroxy-aliphatic acid with chlorsulfonic acid, and neutralizing the resulting product with the desired inorganic or organic base. The sulfonated esters may be prepared by reacting the ester of the corresponding halogenated aliphatic acid with sodium sulfite.

The esters are preferably employed in the form of their neutral soluble salts. The alkali-metal salts, and the salts obtained by neutralizing the acid esters with organic derivatives of ammonia, are especially important. As examples of suitable organic derivatives of ammonia, the

following are mentioned: the alkylolamines (e. g., mono-, di-, or triethanolamine); the alkylol diamines (e. g., l,2-di-(2'-ethanolamino) and l,3-di-(2'-ethanolamin0) -2-propanol); the quaternary alkylolamines, the diquaternary alkylolamines (e. g., tetra-hydroxyethylamine ammonium hydroxide, hexa-hydroxy-ethyl-ethylene diammonium hydroxide); and the quaternary aralkyl-alkyl ammonium hydrcxides or the aralkyl-hydroxyalkyl-ammonium hydroxides (e. g., tri-methyl-benzyl ammonium hydroxide, tri (hydroxy ethyl) benzylammonium hyroxide, etc.).

The valuable eflects resulting from the inclusion of the above described esters in vat dye compositions in accordance with the present invention are noticed both in vat dye pastes and in powders from which dyeing compositions (baths and printing pastes) are prepared and also in the , parently to prevent flocculation of the dye particles. In the vat dye powders, the esters make possible the rapid disintegration of the dye particles in dye baths and aqueous printing compositions, a result which is believed to be due to the fact that the esters are so combined or commingled with the vat dye particles as to :form therewith a composition resembling a solid dispersed suspension. The particles of the vat dyes, therefore, are prevented from combining to form larger particles which would be difficult to disperse in a padding bath or printing paste.

When the vat dye pastes and powders are incorporated with the other usual ingredients of vats, padding baths, or printing pastes, several advantageous results are obtained. First, as previously noted, the compositions may be mixed readily with such ingredients to form homogeneous dyeing compositions. Further, it appears that the esters act to increase the solubility of ieuco dyes and increase the strength and brilliancy of the dyeings and printings obtained. This is because, while ieuco vat dyes are regarded as being soluble in alkaline solutions, and because of this solubility may be taken up by the fiber to be dyed, they are not freely soluble and their increased solubility caused by the esters accelerates the rate of their absorption oradsorption by the fiber.

The vat dye compositions of the present invention are particularly valuable as compared with ordinary vat dye compositions when they are applied to synthetic fibers composed of regenerated cellulose, or to unbleached natural fibers, such as cotton and raw silk. It is known that these latter fibers do not, as a rule, readily absorb the reduced vat dyes because of their coating of natural waxes which act as resist agents.

As before stated, the soluble esters of this invention may be used per se or in admixture with other substances ordinarily used in the art of dyeing or printing textiles. These substances may be in the nature of the alkyl partial inorganic esters specifically disclosed in my patents above referred to, other substances used in dyeing and printing, such as the alkylolamines, polyhydric alcohols, and ethers, e. g., the ethers of diethylene glycol, glucosic compounds, dextrines, gums, starches, etc., or compounds in the nature of printing catalysts, such as heavy metal compounds or the heavy metal salts of alkyl partial esters, such as isobutyl-nickel-sulfate, or the heavy metal salts of the soluble carboxylic esters of the present invention, themselves.

Inasmuch as the quality and dispersibility of the resulting dye composition are dependent to a considerable extent upon the original degree of dispersion of the dye in the suspension or in the dry form, the vat dye is preferably treated in the highly dispersed form. A suitable dispersing agent is preferably incorporated into the dispersion or suspension so as to aid in preventing precipitation and agglutination of the dye particles during storage or during the drying and to increase the fluidity and render easier the incorporation of the soluble salts of the carboxylic acid esters.

Among the dispersing agents which may be employed for this purpose there may be mentioned, for example, the sulfonic acids of henzene, hydyroxybenzenes, naphthalene, hydroxynaphthalenes, their nuclear alkyl, nuclear aralkyl, and hydrogenated derivatives, as well as aldehyde condensation products thereof (as for example, 2,6-naphthalene-disulfonic acid, 1.7- naphthalene-disulfonic acid, 2,8-naphthalenedisulfonic acid, isopropyl-naphthalene-sulfonic acids, dibutyl-naphthalene-sulfonic acids, amylnaphthalene-sulfonic acids, butyl-benzyl-naphthalene-sulfonic acids, cyclo-hexyl-naphthalenesulfonic acids, methylene-(ii(p-naphthalene-sulfonic acid), methylene-di(di-isopropyl-naphthalene-sulfonic acid), in the form of the free acids or salts (e. g., alkali metal salts), etc.; sulflte cellulose waste liquors and their mildly oxidized products and evaporated residues; sulfonated resins; abietene, abietine, and abietane sulfonic acids; soaps; sulfonated higher fatty acids, fats and oils; and the like, as well as mixtures of two or more of such substances.

Further, additional substances having diluent antifoaming, assisting, wetting, catalytic, enolyzing, or other suitable action in the subsequent use of the compositions may also be incorporated into the compositions of the present invention, preferably while the latter are ,in the form of aqueous suspensions or in the form of non-drying pastes containing high boiling alcohols or alcohol ethers.

In preparing the vat dye pastes and powders in accordance with a preferred manner of proceeding, the mixture of vat dye in aqueous or high boiling solvent dispersion is agitated with the appropriate amount of the carboxylic acid ester salt together with the other substances, if added, until a homogeneous paste is formed, or the mixture of the aqueous suspension of the dispersed vat dye and acarboxylic acid ester salt together with the other substances, if added, is evaporated with agitation until a thick paste is formed, with or without the aid of vacuum and preferably at a temperature not exceeding C. The resulting paste constitutes a valuable vat dye paste. If desired, it may be brought to substantial dryness to form a dry vat dye composition. Thus, the paste may be evaporated to dryness on an atmospheric or vacuum rotary drum drier, and the dry product scraped off in the form of flakes. scales, or grains which may be used as such; or the paste, with or without preliminary evaporation, may be admixed with a suitable hydrateforming soluble salt in an anhydrous condition,

such as anhydrous trisodium phosphate, and the,

admixture stirred to produce a dry product. If desired, the dry product may be disintegrated in any suitable manner into a powder.

Mixtures of the carboxylic acid ester salts or mixtures of them with alkyl inorganic ester salts, disclosed in my patents referred to above may also be employed in accordance with the present invention. Further, the esters used in the compositions of the invention may be used together with or in place of the esters disclosed in my applications Serial Nos. 253,346 and 253,347, filed of even date herewith.

The amount of the soluble carboxylic acid esters employed in the preparation of the compositions of the present invention may be varied over a considerable range, depending in part' upon the concentration of-vat dye in the composition, the use to which the composition is to be put, and whether or not other diluents and other materials having a catalytic, assisting, wetting, enolyzing, dispersing, or other action, are included in the composition.

The invention may be employed in connection with vat dyes of all types including those derived from anthraquinones, indophenols, various indigoid, thioindigoid and indirubin compounds, etc.: as for example, indanthrones, pyranthrones, flavanthrones, dibenzanthrones, isodibenzanthrones, perylene quinones, anthranthrones, dibenzpyrene quinones, anthrimidocarbazoles, naphthacrldones, indigo, thioindigo, indirubin, etc., including derivatives thereof, such as their halogen,'nitro, sulfur, and/or alkoxy derivatives.

It should be noted that while the vat dyes in the compositions of the invention are preferably in the unreduced form, they may also be in the reduced or leuco form. For example, leuco ester salts of vat dyes and leuco compounds of vat dyes prepared by careful acidification of an alkaline vat, or by other methods, may be used, if desired.

Although it is generally preferable and desirable, in order to take full advantage of their properties, to employ the esters in vat dye pastes in this way, the dye may be introduced into the mixture in the form of a press cake or an ordinary dye or other form of paste, the ester or esters being added at any desired or suitable point in the preparation of the compositions.

In the forgoing description, the use of the vat dye compositionsin the dyeing and/or printing of textile materials has been stressed since this is the most important application of the compositions. The compositions, however, especially when in the form of powders, may be used in the preparation of dispersions of vat dyes for use in the pigment form in the dyeing of paper, the tinting of fibers and other materials, and the like. The ready dispersibility of the compositions makes them especially valuable for such purposes.

The invention will be further described in connection with the following specific examples (in which the parts are by weight) which are given condition on standing. The paste is especially adapted for incorporation with the usual additional ingredients for the preparation of padding baths and printing pastes which give dyeings and printings of increased strength and brilliancy as compared with the dyeings and printings obtained with the same compositions but omitting the sodium isobutyl sulfoacetate.

Example 2 Example 3 3600 parts of National Vat Pink FF (6,6'-dicider-4,4-dimethyl-thioindigo) in the form of a press cake containing about per cent of dye solids and the rest principally water are mixed thoroughly with 480 parts of sulfite buck (a sulfite waste liquor product) dissolved in 800 parts water. To the resulting mixture 8.l5 parts of caustic soda, 3180 parts of dynamite g ycerine,

to illustrate the invention. It will be realized, 1

however, that the invention is not limited thereto but that changes may be made in the materials treated and their proportions, manipulative steps, and other conditions without departing from the scope of the appended patent claims.

Example 1 1800 parts of National Vat Brown G (di-naphthyl-thioindigo) in the form of a press cake containing about 16 per cent of dye solids and the rest principally water, are mixed with 36 parts of Tamol NNO (which is the sodium salt of a naphthalene sulfonic acid condensed with formaldehyde), 80 parts of the ethyl ether of ethylene glycol and 100 parts of glycerine, and 187 parts of sodium isobutyl sulfoacetate are then added and the whole is mixed thoroughly. The resulting dilute paste is then evaporated at a temperature of about 100 C. to form 1800 parts of a vat dye paste in which the vat dye particles are thoroughly dispersed and which remains in fluid and 540 parts of sodium isobutyl sulfoacetate are added and the resulting mixtureis agitated to form a dilute paste which is then evaporated as described in Example 1 to form 6000 parts of a vat dye paste. Similarly to the paste described in Example 1, the vat dye paste of this example is especially adapted for use in the preparation of padding baths and printing pastes which give unusually valuable dyeings and printings.

Example 4 400 parts of indigo paste (containing 20 per cent pure indigo as shown by indigotin titration and resulting from the precipitation of indigo from an alkaline solution of indoxyl by aeration) are stirred with 2 parts Leukanol (a condensation product of naphthalene sodium sulfonate with formaldehyde) until a thin fluid paste is obtained. 13 parts cane sugar and 5 parts 2-methyl-1-pentanol sodium sulfobutyrate are then added, the mixture being stirred until solution of the sulfo alkyl ester is complete, and the resulting mixture is then evaporated with stirring until a thick paste is formed. The thick paste is then evaporated to substantial dryness either by means of a rotary double drum drier or else placed in drying pans in vacuum. The dry product is ground and screened. An indigo powder is obtained containing 80 per cent indigo which. when added to water or the dye liquor, disperses readily. When employed for the preparation of an indigo vat with the aid of the usual reducing agents (e. g., sodium hydrosulfite and caustic soda) the powder disperses instantly and reduces very rapidly producing a clear vat which dyes cotton'yarns an even blue shade of high tinctorial value.

Example 5 and screened through a 60 mesh screen. The resulting product is a violet colored powder instantly dispersible when added to water and is especially suitable for the dyeing of piece goods by the pad-jig dyeing process. When the powder is made into a printing paste containing the usual ingredients used for the printing of vat dyes, the prints obtained therewith yield very brilliant violet shades, fully penetrated and level.

Example 6 2765 parts of Carbanthrene Flavine GC (Color Index No. 1095) press cake containing 13.8 per cent total solids, of which approximately 11 per cent represent actual dyestuff, are stirred in a beaker while 95 parts Tamol NNO are added until a fluid paste is obtained. Thereafter, parts trisodium citrate, 320 parts sodium isobutyl sulfoacetate dissolved in 320 parts water, and 1600 parts dynamite glycerine are added in succession and the 5111 parts then obtained are subjected to evaporation until 3200 parts of a color paste are obtained. This paste is then passed through a micropulverizer, finally screened through a 200 mesh screen, and is ready for use as a printing color. Unusually strong and well penetrated yellow prints are obtained therewith.

Example 7 To 4410 parts Brilliant Indigo KMR (6,6'- dibrom-indigo) paste containing 20 per cent actual dye solids, 1800 parts dynamite glycerine are added and the mixture is then evaporated in a glycerine bath at 100 C. to a total of 2923 parts of concentrated color paste. A color paste espe-- cially suitable for printing is then obtained therefrom as follows:

To 2260 parts .of the above concentrated color paste, 200 parts water, 140 parts isobutyl sodium sulfoacetate dissolved in 172 parts water, and 28 parts diacetone alcohol are added, giving a total of 2800 parts of an Indigo KMR color paste which when thoroughly mixed is screened and is then ready for use. When made up into a vat dye printing paste, very deep and fully penetrated navy blue shades are obtained therewith.

In the above examples, the esters used may be replaced by equivalent amounts of anyone or a mixture of the class herein disclosed; for example, any one or a mixture of the esters specifically mentioned above.

The process'of making the vat dye compositions of the invention, either in paste, powder, or flake form, is further applicable to any vat dye. Thus any vat dye of the previous examples may be replaced by any of the following:

- Color Index No. Brilliant Indigo 4G 1189 National Vat Scarlet G 1228 National Vat Violet R 1222 National Vat Green G 1199 Carbanthrene Yellow G 1118 Carbanthrene Golden Orange 2RT 1097 Carbanthrene Golden Orange G 1096 CarbanthreneBlue Green FFB 1173 Carbanthrene Violet 2R 1104 Carbanthrene Dark Blu DR 1099 Carbanthrene Flavin GC 1095 Carbanthrene Blue GCD 1113 National Vat'Orange R 1217 The process is of special value for the compounding of blacks of the anthraquin'one or indigo-thioindigoid series.

The esters of this invention may also be added directly to printing pastes whereby unusual re- Example 8 A standard printing thickener is prepared as foll0ws:

Parts Corn starch British g 300 Gum tragacanth 5% solution" 100 Water 500 are thoroughly mixed together and boiled to a smooth paste. To 520 parts of the above paste are added 170 parts K200: and 60 parts H20. and heat applied until a homogeneous paste is obtained. After cooling of this paste to about 150 F. there are added 140 parts sodium formaldehyde sulfoxylate, 50 parts glycerine and 60 parts water, and the paste stirred until all ingredients are thoroughly mixed and dissolved. A blue vat dye printing paste is then prepared by adding to 200 parts Carbanthrene Blue GCD (Color Index No. 1113) 680 parts of the above printing thickener, and parts n-amyl sodium sulfoacetate, stirring until the ingredients are thoroughly mixed and dissolved. Cotton and rayon fabrics are printed therewith by means of a rotary intaglio printing machine; the material is then dried and aged for 4 minutes in an air-free ager at 102 C. (saturated steam) after which the prints are rinsed in cold running water, soaped at the boil, rinsed, and dried. Thus a very brilliant heavy shade of blue is obtained which shows superiority in brilliance, penetration, levelling and fastness to crocking versus prints obtained with the same printing paste but when the n-amyl sodium sulfoacetate has been left out.

In the above example the n-amyl sodium sulfoacetate may be replaced by any one of the esters disclosed above.

I claim:

1. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding processes comprising, in addition to a vat dye compound and a small amount of a dispersing agent, a soluble organic ester of an aliphatic monocarboxylic acid containing 2 to 4 carbon atoms and an aliphatic alcohol containing 2 to 6 carbon atoms, said ester containing at least one solubilizing radical selected from the group consisting of the sulfonate, sulfate, and phosphate radicals.

2. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding processes comprising, in addition to a vat dye compound and a small amount of a dispersing agent, a soluble alkali metal salt of an organic ester of an aliphatic monocarboxylic acid containing 2 to 4 carbon atoms and an aliphatic alcohol containing 2 to 6 carbon atoms, said ester containing in the acyl radical thereof at least one solubilizing radical selected from the group consisting of the sulfonate, sulfate, and phosphate radicals.

3. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding processes comprising, in addition to an unreduced vat dye and a small amount of a dispersing agent, a soluble organic ester of an aliphatic monocarboxylic acid containing 2 to 4 carbon atoms and an aliphatic alcohol containing 2 to 6 carbon atoms, said ester containing a sulfonate radical in the acyl radical thereof.

4. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding processes comprising, in addition to an unreduced vat dye and a small amount of a dispersing agent, an alkali metal salt of an ester of an aliphatic alcohol and an aliphatic monocarboxylic acid containing 2 to 4 carbon atoms, the alcohol residue of said ester containing 2 to 6 carbon atoms, said ester containing a sulfonate radical in the acyl radical thereof.

5. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding processes comprising, in addition to a vat dye compound and a small amount of a dispersing agent, a soluble salt 01' an ester oi an aliphatic alcohol and sulfoacetic acid, the alcohol residue of said ester containing 2 to 6 carbon atoms.

6. A vat dye composition for use in the preparation ot printing pastes and padding baths comprising an unreduced vat dye, a dispersing agent, and an alkali metal salt an ester of an allphatic alcohol and sulfoacetic acid, the alcohol residue of said ester containing 2 to 6 carbon atoms.

7. A vat dye paste for use in the preparation of printing pastes and padding baths comprising an unreduced vat dye, a dispersing agent, and sodium isobutyl sulioacetate.

8. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding p comprising, in addition to a vat dye compound and a small amount oi a dispersing agent, a neutral soluble salt of isobutyl sulioacetate.

9. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding p comprising, in addition to an unreduced vat dye and a small amount oi a dispersing agent, an alkali metal salt of isobutyl sulioacetate.

10. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding processes comprising, in addition to a vat dye compound and a small amount of a dispersing agent, a neutral soluble salt of isobutyl sulfobutyrate.

11. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding processes comprising, in addition to an unreduced vat dye and a small amount of a dispersing agent, an alkali metal salt of isobutyl sultobutyrate.

12. A vat dye paste for use in the preparation of printing pastes and padding baths comprising an unreduced vat dye, a dispersing agent, and sodium isobutyl suliobutyrate. Y

13. A vat dye composition for use in connection with the coloring oi textile fibers by printing and pigment padding processes comprising, in addition to a vat dye compound and a small amount of a dispersing agent, a neutral soluble salt of an ester of an aliphatic monocarboxylic acid containing 2 to 4 carbon atoms with an alcohol containing 6 carbon atoms.

14. A vat dye composition for use in connection with the coloring of textile fibers by printing and pigment padding processes comprising. in addition to an unreduced vat dye and a small amount of a dispersing agent, an alkali metal salt of cyclohexyl sulfoacetate.

15. A vat dye paste tor use in the preparation oi printing pastes and padding baths comprising an unreduced vat dye, a dispersing agent, and

sodium cyclohexyl sulioacetate.

JEAN G. KERN.