Патент USA US2130416код для вставки
Patented Sept. .20, 1938 2,130,416 ' UNITED STATES PATENT OFFICE 2,130,416 DYEING Arthur J. Buchanan, Charlotte, N.- 0., assignor, by mesne assignments, to Southern Dyestu?? Corporation, Charlotte, N. 0., a corporation of North Carolina .No Drawing. Application June 19, 1936, Serial No. 86,078 2 Claims. (Cl. 8-6) This invention relates to improvements in the etc.; in which case the sulphur dyestufi is ?rst dissolved and reduced in a highly alkaline solu art of dyeing with sulphur or sulphurized dye stuiis, andmore particularly to the production tion of sodium sulphide and the alkalinity of the of concentrated solutions of such dyestu?s, and solution is subsequently reduced in an attempt it includes an improved method. of making such to prevent or minimize injury to the ?bers and solutions and the concentrated liquid sulphurized other objectionable effects of strongly alkaline dyestuffs resulting therefrom. ~ The sulphur or sulphurized dyestu?s are gen erally speaking insoluble or sparingly soluble in water, but they are soluble in solutions of sodium sulphide. In order to use these colors for dyeing purposes it is necessary that they be made soluble and reduced. It is also important that these colors, after being dissolved and reduced; remain in solution in the reduced state until the dyeing operation is complete. - The usual procedure in applying sulphur dye stu?s to the ?ber is to dissolve and reduce the . dyestuif with the aid of sodium sulphide and an 20 alkali such as sodium carbonate (soda ash). Other or additional reducing and solubilizing agents are sometimes used, either alone or With sodium sulphide. The ‘ dissolved and reduced dye liquors. ' The present invention is based upon the dis covery that improved results can be obtained by the use of sodium disulphide (NazSz) instead of the ordinary sodium sulphide <NazS), as the dis solving and reducing agent for sulphurized dye stuffs. The sodium disulphide has a greater reduction capacity or potential for a given unit of weight of strength than does the ordinary sodium sul phide, due evidently to the greater amount of combined low valent sulphur which the sodium disulphide contains. Because of this it is possi ble to use less of the sodium disulphide, with resulting bene?cial results in that there is less alkali present during the dyeing and, conse quently, less saponification of the natural oils and waxes in the cotton; consequently the cot ton is left in better condition, more nearly ap proximating natural, untreated cotton. It is dyestuifs are subsequently diluted and the cot 25 ton or other fabric or ?ber immersed in the liquor, with subsequent exposure to the air, etc. In dyeing cotton, for example, ‘the cotton is com ' possible also to produce shades which are brighter monly immersed in the dye liquor at a tempera ture near the boiling point’for a suitable period 30 of time, e. g., around one hour, followed by ex posure to the air, etcl and fuller. . _ The use of sodium disulphide as a reducing agent has the added advantage or additional bene?cial property that it is more stable toward The preparation of dye liquors by dissolving oxidation than sodium sulphide; that is, it oxi and reducing the sulphurized dyestuffs with sodium sulphide, or with sodium sulphide and 35 alkali, has certain well known and commonly recognized objections. The solutions are strong dizes more slowly and this makes it a more de ly alkaline and have the disadvantage of remov ing the natural waxes and fats from vegetable and animal ?bers and tend to leave the dyed ma 40 terial depleted in these constituents and with a harsh texture, unlike the softness of. texture of the original undyed material. Sodium sulphide, when used as a reducing and dissolving agent for the sulphur colors, also has the objection that 45 it is readily oxidized by the air, thus tending to lose its value for keeping the dyestuff in a state of reduction and in solution. Sodium sulphide crystallizes from‘ strong solutions and is conse sirable reducing agent for use in concentrated liquid dyestu? solutions which are marketed in that form. Because of the advantageous properties which sodium disulphide possesses as a dissolving and reducing agent for sulphurized dyestuffs, highly concentrated dye solutions can be obtained by it use, which concentrated solutions, because of their desirable properties, can advantageously be marketed in that form._ _ The use of solutions of sodium disulphide for dissolving and reducing the sulphurized dye 45 stu?‘s gives directly a solution of the reduced dye which is less caustic and more stable toward oxidation than when sodium sulphide is used. quently dl?icult to ?lter in high concentrations. ' The dyestuffs are readily kept in solution in a In an attempt to overcome the objections to the use'oi sodium sulphide in preparing reduced solutions of sulphur dyes, it has been proposed to reduce the high alkalinity of the dye solution, for example, by the use of sodium bisulphite, 55 sodium hydrosulphite, glucose, salts of ammonia, '- sodium disulphide solution and can be handled 50 in a concentrated form. Such dye solutions in general produce brighter and fuller shades, leav ing the dyed material less harsh, and are less alkaline and of a lower pH value than solu tions in sodium sulphide. 2 2,130,416 The new dye liquors or solutions can readily be used for dyeing vegetable ?bers and fabrics and various arti?cial ?bers, and also for print ing with the sulphur colors. The method of application of the new dye stuif solutions is similar to that with sodium sulphide solutionsbut with the use of materially lower temperatures; since it has been found that the dyeing temperature can be reduced to around 150° F. with bene?cial results, whereas it is cus tomary to dye with sodium sulphide dye solutions at around 200“ F. This use of a lower tempera ture involves not only a saving in time and cost of steam for heating but leaves’ the dyed cotton 15 in a better condition. ‘ _ I have also found that sodium disulphide can advantageously be employed in combination with sodium hydrosulphide, for example, using the sodium disulphide and sodium hydrosulphide in 20 about equal proportions. I have also found that a very small quantity of caustic soda may be used with the sodium disulphide in which case the solution consists mainly of sodium disulphide with a small amount 25 of sodium sulphide. I have also found that a very small quantity of caustic soda can be used along with the com bination of disulphide and hydrosulphide; in which case the resulting composite solution con 30 tains sodium sulphide, sodium hydrosulphide and sodium disulphide in varying proportions; but the resulting solution has a lower pH value than a sodium sulphide solution and gives bene ?cial results, such as those above mentioned. In making the new dye solutions, and in carry 35 ing out the new dissolving and reduction proc ess, the sodium disulphide is advantageously used in a solution of about 30% strength. Such a solution has a similar reduction capacity to 40 that of a solution of sodium'hydrosulphide of about the same strength and considerably greater reduction capacity as compared with a sodium sulphide solution of similar strength. Highly concentrated solutions of sulphur col 45 ors ‘can be prepared with relative ease by dis solving and-reducing them in a solution of the sodium disulphide, and such highly concentrated solutions can be readily ?ltered, stored, trans ported and used. Solutions of similar high con 50 centration can similarly‘be obtained by the use of admixed sodium disulphide and sodium hy drosulphide without or with the addition of a very small amount of caustic soda. When the sodium disulphide and sodium hydrosulphide are 55 used together with a small amount of caustic soda, the composite solution contains sodium sulphide, sodium hydrosulphide and sodium di sulphide in varying proportions, e. g., with' the quantities of each that may be present in the 60 composite solution varying from a minimum of around 10% up to a maximum of around 80%. In applying the sodium disulphide solution of the sulphurized dyestu?, the highly concentrated solution can be handled much the same as so 65 dium sulphide solutions of the dyestuffs, but with added advantages, such as the use of lower tem peratures and other advantages above men tioned. The concentrated solution-can, for ex ample, be diluted and the fiber or fabric dyed 70 therein and the dyestuif exhausted by the addi tion of sodium chloride, sodium sulphate, am monium sulphate, sodium hydrosulphite, sodium bisulphite, etc. . The sulphur dyestu?’s-are commonly marketed 75 in the form of powders, usually admixed or diluted with more or less salt. Additional salt can be added to aid in the dyeing operation and in exhausting the dye bath. It is common to add a small amount of soda ash or caustic soda to the dye bath; and such alkalies in small amount can be added in the practice of the present proc ess, although excellent results have been ob tained without such addition. ‘ A particularly valuable application of the in vention results from the use of the moist press cake which is produced in the manufacture of sulphur dyes, and without the drying of the dyes to produce a dry ‘powder. Such moist dyestu? press-cakes are readily dissolved and reduced in a strong solution of sodium disulphite, and the resulting solutions are particularly advantageous for use in the dyeing of textile ?bers and fabrics. The use of the fresh moist press-cake and its re duction and dissolving in the sodium disulphide solution eliminates or minimizes the changes 20 which take place on drying of the press-cake to form dry dye powders. Solutions of the sul phurized dyes can be more readily and advan tageously prepared by using the moist press cake than by using the dried dyestuffs which are 25 produced by the drying of the press-cake and which are generally less soluble ‘and. less readily dissolved and reduced. The new disulphide solutions of the sulphur dyes are readily prepared without the use of 30 neutralizing agents such as have heretofore been added to sodium sulphide solutions to reduce their alkalinity. The new dye solutions can thus be prepared free or relatively free from sulphites or bisulphites or other added neutralizing agents. 35 The solutions are initially prepared by dissolving and reducing the sulphur dyes in the disulphide‘ solution so that the solutions are initially of much lower alkalinity and pH value than sodium sulphide solutions, and with other advantages, 40 such as those above mentioned. The invention will be further illustrated by the following specific examples, but it will be under stood that the invention is not limited thereto, since different sulphur or sulphurized dyestuffs 45 can be employed, and somewhat varying amounts and strengths of solutions of sodium disulphide. The following examples are typical: Example 1.-—100 pounds of commercial sul phur black in the form of a dry powder having common salt admixed therewith for standardiza tion are dissolved in from 100 to 200 pounds of a 30% solution of sodium disulphide at a tempera ture of about 80° C., and with accompanying re duction of the dyestu?f. At this temperature and 55 concentration the solution can be readily ?ltered, decanted, etc., to remove insoluble, objectionable matter and a strong, stable solution of the dye stufl thus obtained suitable for storage and transportation or ready for use, by dilution, etc., 60 in making a dye bath for dyeing textile ?bers or fabrics. On cooling of the solution to ordinary temperatures the dyestu? remains in solution, and is ready for use, after dilution, etc. Example 2.-100 pounds of commercial sulphur blue in the form of a dry powder having salt ad mixed- therewith for standardization are dis solved in from 100 to 200 pounds of a 30% solu ‘tion or sodium disulphide and the process is otherwise carried out in a manner similar to that 70 described in Example 1. Example 3.--A sulphurized dyestu?, such as sulphur black or, sulphur blue, sulphur brown, etc., is used in the form of a moist press-cake containing e. 3. around 45% of water; and 100 75 3 2,130,410 pounds of this press-cake is dissolved in from Where the sodium disulphide is used in admix 100 to 200 pounds of a 30% solution of sodium ture with sodium hydrosulphide, the proportions disulphide. The dissolving and reduction take of disulphide and hydrosulphide can be varied, place more readily in this case than with the as above indicated. Similarly, where a .small amount of caustic soda is used in addition to the dry sulphurized dye powder, and somewhat im proved dye solutions are thus obtained without the necessity of isolating‘ and drying the sulphur dye and subsequent handling of dry dye powders with their well known objections due to dusting, 10 and the irritating or toxic effect of the dust, etc. sodium disulphide and sodium hydrosuiphide, the resulting composite solution of sodium sul phide, sodium disulphide and sodium hydrosul phide may also vary in its proportions, as pre _ viously pointed out. The following examples illustrate the produc tion of concentrated solutions of sulphurlzed dye-_ It' is one 01’ the advantages oi‘ the new com posite dye liquor, as well as an advantage of the stu?'s with a composite solution 01' sodium disul dye liquor made with sodium disulphide alone, phide and sodium hydrosulphite either without that lower temperatures can be used in the dye ing process than with the sodium sulphide solu or with the addition of a small amount of caustic soda, in which case the composite solutions con tain sodium disulphide, sodium sulphide and so dium hydrosulphide. _ Example 4.--100 pounds of commercial sulphur black in the form of a dry powder having com monsalt admixed therewith for standardization are dissolved in from 100 to 200 pounds of a com posite solution of sodium hydrosulphide and sodium disulphide containing approximately equal amounts of the hydrosulphide and disul phide in amount su?icient to give a solution of about 30% strength and at a temperature of about 80° C.-, with accompanying reduction of the dyestuff. At this temperature and concentration 30 the solution can be readily ?ltered, decanted, etc., to remove insoluble, objectionable matter and a strong, stable solution of the dyestu? thus ob tained suitable for storage and transportation or ready for use, by dilution, etc., in making a dye 35 bath for dyeing textile ?bers or fabrics. On cooling of the solution to ordinary temperatures the dyestuii‘ remains in solution, and is ready for use, after dilution,’ etc. - Example 5.—A sulphurlzed dyestuii', such as sulphur black or sulphur blue, etc., is used in the form of a moist press-cake containing e. g., around 45% of water; and 100 pounds ot'this press-cake is dissolved, in from 100 to 200 pounds of a 30% solution, containing approximately equal proportions of sodium hydrosulphide, so dium sulphide and sodium disulphide. The dis solving and reduction take place more readily in this case than with the dry sulphurlzed dye powder, and somewhat improved dye solutions - are thus obtained without the necessity oi’ isolat ing and drying the sulphur dye and subsequent handling of dry dye powders with‘ their well known objections due to dusting, and the irritat ing or toxic effect of the dust, etc. The solutions produced in accordance with the above examples are typical and may be used: without or with additional substances, by dilu tion, etc., in making dye liquors or dye baths for dyeing and printing textile ?bers and fabric-a tions commonly used. ' The new composite dyestuif solutions, pro duced by reducing the sulphurized dyestuffs with the sodium disulphide'red'ucing agent, or with the composite reducing agent containing sodium disulphide, are advantageously marketed com mercially as concentrated, reduced dyestuiI solu tions ready for the dyer to use. Various sulphur dyestuifs and various shades of sulphurlzed dyestuffs can be used in making the new dyestu? solutions; for example, such sulphurlzed dyestuilfs and such shades of sul phurized dyestuifs as black, blue, tan, yellow, green, etc., sulphurized dyes. . ‘ , ‘ It will be evident that the above examples can be varied, e. g., in the particular sulphurlzed dye stuil’ employed and in the particular composi tion of the reducing solution, particularly where a composite reducing solution is used. I claim: 1.. Liquid sulphur dye being a concentrated, ?i terable solution of sulphurlzed dyestu? dissolved and reduced in a-concentrated composite solu tion of sodium sulphide, sodium disulphide and sodium hydrosulphide, in which the sodium sul phide, sodium disulphide and sodium hydrosul phide are present in approximately equal amounts, said dye solution containing approxi mately from 18% to 50% of the sulphurized dye stuii', and being characterized by improved sta bility toward oxidation and by relatively low pH value. - v 2. Liquid sulphur dye, being a concentrated, ?lterable solution of suiphurized dyeatu?' dis solved and reduced in a concentrated composite solution of sodium disulphide and sodium hydro sulphide, in which the sodium disulphide, and sodium hydrosulphide are present in approxi mately equalcamounts, said dye ‘solution con taining approximately from 18% to 50% of the sulphurlzed dy'estu?, and being characterized by improved stability toward oxidation and by rela tively low pH value. . ~ ARTHUR. J. BUCHANAN.