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Патент USA US2130416

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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.
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