Improved Process for the Dyeing of Textile Fabrics.
Year: 1899

page_text: Date of Application, 22nd Mar,, 1899-Accepted, 5th Aug., 1899
COMPLETE SPECIFICATION,
Improved Process for the Dyeing of Textile Fabrics.
I, GIOVANNI TAGLIANI, of 26, Via Victoria Colonna, Milan, in the Kingdom
of Italy, 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:.
This invention relates to a process for dyeing raw or bleached cotton or other
textile fabrics in such a manner that the two sides receive different shades for
example, so that by the use of the same colour one side of the fabric may be
dyed darker than the other. For some purposes it is desirable that the stuff
be dyed or coloured on the front side differently from the back side, by which
means a considerable economy of colouring-matter may be obtained.
In carrying out this invention a caustic solution, of an alkali or a salt exer-
cising a strong alkaline reaction, such as aluminate of sodium, in a state of
concentration depending upon the colour in question and the character of the
fabric, is transferred to the side of the fabric which it is desired should receive
This opera-
the deeper colour by means of a roller or any other suitable means.
tion has the advantage, compared with all earlier processes for treating fabrics
with mordants and the usual mercerising processes, that the shrinking of the
fabric or any other physical alteration is avoided, as the contraction which
might take place upon the one side is avoided by the fact that the greater part
of the fabric is not touched by the mordant liquid and the merely superficial
action of the mordant is thus equalised. In this process it is unnecessary to
use a stretching device either before the treatment or afterwards to prevent
shrinkages, as is the case to the great disadvantage of the fabric in the various
mercerising processes adapted in practice. By the application of the concentrated
alkaline solution to the one side of the fabric, this side obtains the property of
absorbing the dye more readily than the other side which has not been so
treated, so that even by using very little dye an exceptionally dark and brilliant
colour can be obtained.
According to the character of the colour used, the action of the alkalies can
be assisted by the presence of metallic salts. such as those of iron, copper, or
manganese and in this manner also any desired shade can be obtained. Care
must be taken that these salts he used in such a form that insoluble precipitates
do not take place upon the fibres in consequence of the action of the alkalies,
and it is therefore advisable to mix the metallic salts with the alkaline solutions
with a slight addition of glycerine, glucose or alcohol and thus prevent the
formation of a film. As it is only of importance to obtain the metallic salts for
obtaining the shades, or rather the oxides of same in a soluble form, it is not
necessary that glycerine and the like he used for some purposes but a solution
of oxide of copper in a lye of soda or iron or manganese-saccharate may for
example be used.
Any oxides arising during the action upon the dres, as well as the excesses
of the metal salts in the solution of alkali may be removed by passing the
fabric after the treatment through sulphuric acid, hydrochloric acid, or sulphurous

page_text: oxalic acid. In order to obtain different shades of the same colour upon
both sides, the salts or alkalies etc. can be applied on both sides and the relative
intensity of the shades then depends upon the relative strength of the solutions
used. If the same amount of substance is applied to both sides the same colour
is obtained, but with greater rapidity and brilliancy.
"
It is self-evident that this process can also be used in combination with the
usual mordant and " reserve methods which do not require to be modified in
any manner. For this purpose the mordant solutions of alkali should preferably
be used at a concentration of 30° Bé., or more, and they can, as already remarked,
be replaced by solutions of aluminate of sodium with or without addition of
lye of soda.
The present process which is suitable for all kinds of dyes can for example be
carried out in the following manner:
For instance litre of a solution of acetate of chromium at 10° Bé. can be
used with 2 litres of lye of soda or potash at 40° Bé.; or instead of the above,
75 grammes of powdered ferro-cyanide of potassium in about 75 c.c. of water with
litre glycerine and 2600 c.c. of Ive of soda can be used. Instead of ferro-
cyanide of potassium, sulphate of iron or hydrate of iron can also be used. When
inanganese salts are used the following proportions may for example be adopted:-
100 grammes chloride of manganese in 100 c.c. glycerine and 2600 c.c. lye
of soda of 40° Bé. The lye of soda or potash can vary between 20-40° Bé.
Instead of the acetate of chromium in the first example freshly precipitated
hydroxide of chromium with or without the addition of glycerine etc. may be
used.
When copper salts are used the following proportions have been found to be
advantageous for most purposes:-
50 grammes of acetate of copper or freshly precipitated hydroxide of copper
with 100 c.c. commercial ammonia, 100 c.c. glycerine and 2700 c.c. lye of soda.
As an example of the use of aluminate of sodium the following sample may be
given: 100 grammes sulphate of aluminium or the equivalent quantity of
freshly precipitated hydroxide of aluminium are used mixed with 200 c.c. water
and 2700 c.c. 40° Bé. of soda.
These proportions may of course vary according to requirements. Also,
beside the salts of iron, manganese, chromium, and copper mentioned above, salts
of tin, zinc, uranium and other metals may be used.
For the production of reserve work the following course is adopted: -The
reserve is pressed on as usual either with a cloth printing machine or with rollers
and the caustic lye is applied over this printed surface of the fabric; the fabric
is then dyed as usual and passes through sulphuric or hydrochloric acid.
In mordant printing the caustic solution is applied to the entire surface of
the fabric by rollers or in any other suitable manner, the fabric is then dyed
and passed through acids such as sulphuric or hydrochloric acid.
These dyed fabrics can be treated with mordants such as bichromate of sodium,
if passed through a solution composed as follows:
4000 parts of water.
200 parts of oxalic acid.
175 parts of sulphuric acid of 50° Bé.
40 parts of glucose.
This solution has a specific gravity of 65° Bé., and it is used at a temperature of
from 50 55° C. The concentration may be varied for special cases. If Mather &
Platts apparatus is used the dyed fabrics are treated with steam mordants
(caustic chlorates).
-
The metallic oxides formed by the alkaline solutions act partially as oxygen
carriers, partially by direct formation of lakes and are preferably only used for
obtaining the deained, chado at the nants of the fahnia tranted and t waist and

page_text: The process is applicable with equal advantage for all goods suitable for
mordant colours whether dry or moist, raw or bleached printed or not printed
and the fabrics can be dyed perfectly evenly on one side only with the greatest
ease and a considerable economy of material.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what
I claim is:―
1st. A process for obtaining a deeper shade of colour on textile fabrics in
dyeing which consists in first applying concentrated caustic lyes with or without
the addition of oxides of aluminium, iron, chromium, manganese, copper, tin,
zinc or uranium, or a mixture of these oxides, soluble in caustic alkalies by
themselves or in the presence of glycerine to the whole surface, not to parts
thereof, of that side of the fabric which it is desired should receive a darker
shade, substantially as described.
2nd. A process for obtaining a deeper shade of colour on textile fabrics in
dyeing which consists in first applying concentrated caustic lyes with an addition
of an oxide of a metal such as aluminium, iron, chromium, manganese, copper,
tin, zinc, or uranium to the whole surface, not to parts thereof, of that side of
the fabric which it is desired should receive a darker shade, substantially as
described.
3rd. A process for obtaining a deeper shade of colour on textile fabrics in
dyeing which consists in first applying concentrated caustic lyes with an addition
of a mixture of two or more of the oxides of aluminium, iron, chromium, manga-
nese, copper, tin, zinc and uranium to the whole surface, not to parts thereof,
of that side of the fabric which it is desired should receive a darker shade,
substantially as described.
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