Process for Dyeing Loose Cotton, Cotton Thread, and Woven Fabrics.
Year: 1892

page_text: Date of Application, 18th Mar., 1892
Complete Specification Left, 19th Dec., 1892-Accepted, 18th Mar., 1893
PROVISIONAL SPECIFICATION.
Process for Dyeing Loose Cotton, Cotton Thread, and Woven
Fabrics.
I, GUSTAV JAGENBURG of Rydboholm in the Kingdom of Sweden, Chemist,
do hereby declare the nature of this invention to be as follows:-
The present invention relates to a process for dyeing loose cotton, cotton thread,
and woven fabrics, with an aniline black which is permanent, and will in no way
injure the fibres. The process consists in producing insoluble, or only slightly
soluble, combinations of aniline and a metallic salt, with the simultaneous use of
"re-acting "quantities of chlorates, chromates, permanganates, peroxides, or other
oxydising substances; then fixing the above mentioned combinations in the fibres;
allowing the same to become, while dry, partially oxydised, when the resulting
color will be finally transformed into a deep black.
If a concentrated solution of aniline salt be mixed with a similar one of acetate of
copper, two different and well characterised precipitates of double combinations of
either salt, according to the proportion of the quantities, will be obtained.
If the aniline salt were greatly in excess, a dark olive-colored, glittering, metallic,
crystalline precipitate would be obtained; contrariwise, if the acetate of copper
were to preponderate, a scaly, dull, greenish-yellow tinted body would be the
result. Both are but slightly soluble in water; in fact, the yellow is almost
insoluble; but both readily dissolve in acetic acid, muriatic acid, and other acids,
both change and oxydise in the air; and can be transformed into aniline black
by suitable means. If cotton be dipped in the separated salt solutions, first in
one and then in another, so will (according to the order in which this takes
place) the one or the other of the above precipitates be obtained upon it.
If some acetic acid be added to the aniline salt solution, and then precipitated
with acetate of copper, the solution assumes an olive green tint; it throws down,
however, no precipitate; the liquid remains clear.
According to the new process of dyeing with aniline black, I operate as
follows:-
(1.) I impregnate the cotton with the clear bath liquor of an aniline salt; for
instance, muriate, sulphate, nitrate, oxalate of aniline; a salt of copper, iron,
manganese, or vanadium, and free acetic acid, e.g. :—

page_text: the moment of complete drying, the fibres assume an olive green tint, that is, of
course, if copper acetate be employed.
Then follows:-
(3.) The half oxydation, in the dry state, of the cotton, by laying it out or
hanging it up in rooms or compartments ventilated and warmed to a moderate
temperature of about 25° to 30° Cels., for from 3 to 4 days, till the cotton assumes a
grass green tint. This half oxydation serves the purpose of more completely fixing
the aniline in the fibres by half oxydising the double combinations formed during
drying. It is, in fact, a half oxydation, because it is not oxydised far enough to
produce the well known dark emerald green, such as has been obtained by the usual
methods. This moderate oxydation makes it also impossible that the fibres should
be injured, or that the black should come off.
Lastly: The transformation into a full aniline black, by an oxydising bath of
chromate and chlorate of soda, or of chromate of soda and a salt of oxide of iron,
at a temperature not exceeding 40° C., for from 1 to 6 hours, according to the
progress of the process. The cotton is allowed to remain in this bath till a deep,
full black is obtained, which will not turn green; it is then washed and dried.
These oxydation baths, which, if the work is properly carried on, must keep quite
clear, consist of:
COMPLETE SPECIFICATION.
Process for Dyeing Loose Cotton, Cotton Thread, and Woven
Fabrics.
I, GUSTAV JAGENBURG of Rydboholm, in the Kingdom of Sweden, Chemist, do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
The present invention relates to a process for dyeing loose cotton, cotton thread,
and woven fabrics, with an aniline black, which is permanent, and will in no way
injure the fibres. The said fabrics may consist either of cotton alone, or of a
mixture of cotton with wool or silk, and termed half wool or half silk fabrics.
The process consists in producing insoluble, or only slightly soluble, combinations
of aniline and a metallic salt, without the simultaneous use of "re-acting" quantities
of chlorates, chromates, permanganates, peroxides, or other oxydising substances;
then fixing the above mentioned combinations in the fibres; allowing the same to
become, while dry, partially oxydised, when the resulting color will be finally
transformed into a deep black.
If a concentrated solution of aniline salt be mixed with a similar one of acetate
of copper, or with a mixture of acetate of copper and acetate of alumina, two
different and well characterised precipitates of double combinations of either-salt,
according to the proportions of the materials used, will be obtained.
If the aniline salt were greatly in excess, a dark-olive colored,glittering, metallic,
crystalline precipitate would be obtained. Contrariwise, if the acetate of copper,
or the mixture of acetate of copper and acetate of alumina, were to preponderate,
a scaly, dull, greenish yellow tinted body would be the result. Both are but slightly

page_text: soluble in water; in fact, the yellow is almost insoluble, but both readily dissolve
in acetic acid, muriatic acid, and other acids; both change and oxidize easily in
the air, and can be tranformed into aniline black by suitable means.
If cotton be
dipped in the separated salt solutions, first in one and then in another, so will
(according to the order in which this takes place) the one or the other of the
above precipitates be obtained upon it.
If, now, some acetic acid or other suitable acid be added to the aniline salt
solution, and the mixture be further treated with acetate of copper, or a mixture of
acetate of copper and acetate of alumina, the solution assumes an olive green tint ;
it throws down, however, no precipitate; the liquid remains clear, and retains its
lustre for a long time.
According to the new process of dyeing with aniline black, I operate as
follows:-
(1). I impregnate the cotton with the clear bath liquor of an aniline salt, for
instance, muriate, sulphate, nitrate, oxalate &c., of aniline, a salt of copper, iron,
manganese, alumina or vanadium, and a suitable acid, for instance, acctic or
oxalic acid, e.a. :—
100
"
acetate of alumina ;
15.30
"
acetic acid, of 8 Bé.
The addition of chloric salts, etc., may be entirely omitted,-
-or only used in small
quantities, say, from 2 to 4 gr. to the 1000 gr. of liquid, in order that the chloric
acid set free by the oxidation may absorb sufficient of the metal salts, which have
now become basic, and may not attack and weaken the cotton.
The impregnation is effected by hand or machine in the customary way, or with
the assistance of vacuum apparatuses. The surplus of the bath, which remains
unchanged and retentive for a considerable time, is drawn off and used again.
The next step is :-
(2). The drying of the cotton or other goods at a not too great temperature,
about 25 to 30 Cels. As the result of this, the solutions concentrate, the acetic
acid evaporates, and is removed by ventilation. The precipitate of the above
mentioned double combination between aniline and a metallic salt, forms on, and
fixes itself in, the fibres. Immediately after complete drying has been effected, the
fibres assume an olive green tint.
(3). After this has been done, the fibre is laid out or stored in a suitable room
or compartment, warmed to a temperature of about 25° to 30° Cels., until it assumes
a grass-green tint. This "half oxydation" serves the purpose of more completely
fixing the analine in and upon the fibres, by half-oxydising the double combinations
formed during drying. This oxydation is, in fact, a half oxydation, because it is
not oxydised far enough to produce the well known dark emerald green, such as
has been obtained by the usual methods. This moderate half-oxydation makes it
also impossible that the fibres should be injured.
(4). Lastly follows the transformation into a full aniline black, by a sufficiently
strong (2 to 4° Beaumé) oxydising bath of chromate of soda or potash, or of
chromate of soda or potash in combination with a chloric salt (in equal parts), or
with a salt of oxide of iron (in this case, 4 parts of a chromic salt and 1 part of an
iron oxide salt), at a temperature not exceeding 40° C.
The cotton or other goods are treated in batches in this oxydation bath, and each
separate batch, after being taken out of the bath, is wrung out until it only retains
just its own weight of liquid.
The liquid wrung or pressed out of the batches, is allowed to flow back into the
bath, and there is added to it, so much fresh liquid, before immersing the new batch,
as is equal to the weight of this batch, or as the previous batch has abstracted
from the bath.

page_text: After 2 or 3 such batches of dyed goods have been treated in the bath, there is
formed in the oxydation bath, at the same time, an aniline dye bath, in consequence
of the aniline particles which have not become sufficiently fixed in the fibre, becoming
detached from the goods during agitation in the bath. This process is repeated
with every batch treated in the bath.
The aniline dye bath formed in this manner, has this advantage, that all the
dye stuff that the aniline salt employed can yield, is deposited on the fibre, because
the aniline particles detached from the various batches, are taken up by the
succeeding ones, these again parting with a portion of their aniline. This giving
off and re-absorbing of the aniline salt goes on, however, without affecting the
clearness of the bath. The remaining aniline left in the bath is used up by
re-dipping the first two or three batches of goods that were treated in the bath.
In this way, the aniline is completely used up, and a cheap method of dyeing
thereby results.
The batches so treated are hung up or laid out in a cool place for several hours,
or in a chamber heated to from 36 to 40 C. for about half an hour. The goods are
then washed thoroughly, and the operation is then finished.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A process for dyeing an aniline black, that will not turn green, is not fugitive,
and will not attack the fibres, loose cotton, cotton yarn, and woven fabrics, either
wholly of cotton or cotton and wool, or cotton and silk, in which process a complete
absorption of the aniline employed and also of the oxydation material (and conse-
quently a cheap mode of dyeing) is obtained, such process consisting therein, that
the fibrous mass, after being impregnated with a bath of an aniline salt, a metal
acetate, an organic acid, and water (to which may be added a small quantity of
chloric salt), and then dried, is laid in or hung up in a ventilated chamber, to
effect a "half" oxydation, after which the fibre is taken in batches and immersed
in a lukewarm (40° C. at the most) solution of a chromic acid salt, or of a
chromic acid salt and an oxide of iron salt, or of a chromic acid salt and a chloric
acid salt, and in which process, before treating a fresh batch, so much chromic
solution (oxydation solution) is added, as the previous batch had absorbed, the
batches, after being freed from the superfluous oxydation liquid, being spread out
or hung up in a cool place for 5 or 6 hours, or in a warm room for or of an
hour, and finally thoroughly washed.