Improvements in the Development or Treatment of Colouring Matters in Textile Fabrics or Materials.
Year: 1890

page_text: 'Date of Application, 3rd June, 1890-Accepted, 30th Aug., 1890
COMPLETE SPECIFICATION.
Improvements in the Development or Treatment of Colouring
Matters in Textile Fabrics or Materials.
1 JOHN JOSEPH HART, of The Merrimack Manufacturing Company of Lowell, in
the State of Massachusetts one of the United States of America, Calico Printer
do hereby declare the nature of this invention and in what manner the same is
to, he performed, to be particularly described and ascertained in and by the following
statement:
'
This invention relates to a novel method by which a lake or color fixed in a
textile fabric, may be developed or varied in shade to produce the shade of color
desired.
In color printing, as now commonly practiced, the fabric, either cotton or wool
or mixture of both, in the form of a web, is subjected to the following chief
operations or steps, viz. -The coloring matter mixed with a mordant or like
mixture of reacting bodies, which constitates the color or dye of the printer, is
printed upon or applied to the fabric by means of suitable printing machinery,
such as rollers;
2nd. The said color or dye is then fixed or formed into a lake in the cloth by
the ordinary operations, such as drving or steaming, and the said lake or color
fixed in the cloth is then developed or brought to the required shade, by passing
the printed fabric through a hot bath containing the reagent or developing sub-
stance, which for example may be bichromate of potash, tartar emetic, or other
suitable or well known reagent.
As the printed fabric passes through the hot bath referred to, the chemical
reaction between the lake and the developing reagent is effected by the heat of
the bath, which is maintained at the temperature suitable to effect the chemical
reaction, which temperature may be varied according to the nature of the reagent
or fabric, that is, the lake or color fixed in the fabric is chemically reacted upon
by the bichromate or other reagent to produce the desired shade of color.
It has been found in practice that a portion of the lake or color printed upon
the fabric by the printing rollers together with foreign matters on the cloth, such
as starch, etc., applied in the prior preparations of the cloth, is mechanically
detached or dissolved by the agitation of the liquid of the hot bath referred to,
and also by the passage of the fabric through the apparatus, so that the detached
or dissolved color or lake and foreign matters not only conta ninates the said bath
and renders it worthless after little use, and before the bichromate or other reagent
has been entirely or wholly utilized, but also stains or otherwise disfigures the
pattern printed upon the fabric.
This is especially true when a portion of the fabric is not printed upon, so as
to leave a white ground or figure in the design, and in this case the white portion
not only becomes discolored or injured by the contaminated solution of the bath,
but also by the detached or dissolved lake or color running down over the fabric,
as it is passed through the portion of the apparatus above the vat containing
contaminated reagent.
I have discovered by experiment that the deleterious effects obtained in the
developing part or process of color printing, as now commonly practiced and above
referred to, may be obviated by effecting the chemical reaction between the
developing reagent and the color or lake in the fabric, after the printed fabric
has passed out of and away from the bath of the developing reagent.
In accordance with my invention therefore, the bath of developing reagent is
maintained at a suitable temperature below the point necessary to effect the desired
| chemical reaction, (it being preferably cold) and the said chemical reaction between

page_text: the reagent and color or lake in the fabric is effected outside of the said bath, by
passing the fabric over or about hot cylinders or in other well known manner of
heating, such as by passing it through a steam chest.
The particular features in which my invention consists will be pointed out in the
claim at the end of this Specification.
Fig. 1 shows in section a sufficient portion of one form of apparatus with which to
practice my invention, to enable it to be understood, the vat containing the reagent
being in section, and
Fig. 2, a modification to he referred to.
The vat A containing a solution A¹ of bichromate, tartar-emetic, or other developing
reagent, supports a frame a in which is mounted bearings a¹, a² of rolls a³, a, the
hearing a being herein shown as fixed or stationary, it being fastened as shown by
bolts a, and the bearing a being movable in the frame a as shown, by means of
adjusting screws a°, only one of which is shown, to adjust the position of the roll a¹
with relation to the roll a³ for a purpose as will be described.
The roll a will preferably be of brass or other suitable metal, and the roll a'
preferably of india rubber or other elastic or yielding material, or it may be a
wooden or other roll having a covering of india rubber or other elastic or yielding
material.
The fabric b, which may be of cotton, wool, or a mixture of both, or other textile
material on which a mixture of coloring matter and mordant or like reacting body
has been previously applied in any suitable or well known manner, and then fixed or
formed into a lake in the cloth by subsequent operations, such as steaming or drying,
etc., is first passed under a roller b', as shown in Figs. 1 and 2, then over a roller 2
and under a third roller 3, and then between the squeezing rollers a³, a³, by which
the surplus liquid or solution A¹ in the fabric is pressed out thereof, it dropping by
gravity back into the vat A.
The solution A containing the developing reagent, such as bichromate of potash or
soda, tartar-emetic, or other suitable reagent, may be supplied to the vat A, by a
suitable pipe not shown.
The solution A¹ in the vat is maintained at any temperature suitable, but below the
point or degree of heat necessary to effect the chemical reaction between it and the
lake or color fixed in the fabric; the said solution being preferably admitted into
the vat cold, whereby the color or lake in the fabric is not. dissolved or detached.
"'
The rollers 6, 63, serve to bind the cloth upon the roller 62, technically known as
the "stretcher or opener," by which the cloth is opened and freed from folds and
serimps.
The roll a may he removed toward or away from the roll a³ to expel more or less
of the solution containing the developing reagent from the fabric as the case requires,
so that the proper amount of developing reagent may be left in the fabric to effect the
best or desired result.
In practice, the fabric is passed through the vat A in the form of a web, it being
composed of a number of separate pieces sewed or othewise secured together.
After passing the squeezing rolls a³, a', the web of cloth b containing the color or
lake and solution of developing reagent is heated to effect the chemical reaction
between the color or lake and the developing reagent.
As shewn in Fig. 1, the heat referred to is obtained by means of revolving
cylinders c, c', around about which the web b is passed, it being first passed, as
shewn, over a roller c² located substantially as shewn, to utilize the maximum amount
of the heating surface of the cylinder c.
The cylinders c, c', are shown as supported by a frame consisting of brackets e
secured to standards, only one of which is shown, the said cylinder being preferably
heated by steam--admitted..into them- through a suitable inlet, not shown, as for
instance a hollow journal, as usual with apparatus of this class:-
Instead of the steam cylinders c, c¹, the necessary heat to effect the chemical
reaction may be obtained by means of a steam chest c, see Fig. 2, provided with a
steam inlet and outlet, not shown, or in other suitable or usual manner.

page_text: By subjecting the printed fabric to the solution containing the developing reagent
maintained substantially cold, that is, below the temperature or point of reaction, the
said fabric becomes saturated, padded, or impregnated with the said developing
solution, which being substantially cold does not dissolve or detach the color or lake
and foreign matter from the goods during their short immersion, so that the developing
solution expressed from the fabric by the squeezing rolls returns to the vat A clear
and uncontaminated with foreign coloring matter.
It will thus be seen that the solution containing the developing reagent may be
entirely consumed or utilized, thus obviating delays necessary to replace the con-
taminated solution, and rendering the process continuous, whereby a greater quantity
of work may be accomplished in a given time.
Furthermore, the discoloring or staining of the white ground or figure of the
fabric is also entirely obviated.
I do not desire to limit my invention to the use of rolls to free the surplus
developing solution or reagent from the fabric, as other devices may be employed, as
for instance centrifugal machines, or the fabric may be allowed to drain before being
heated, in which case the cold or substantially cold developing liquid running down
over the fabric would not dissolve out or detach any of the color or dye from the
fabric.
In practice the fabric is not entirely dried by the cylinders c, c¹.
In order that my invention may be fully comprehended I will specifically describe
my process as applied in practice, viz.:
-
The coloring matter mixed with tannic acid is applied to the cloth by printing
rollers or in other suitable manner, preferably in the form of a design, and the cloth
is then treated, as by steaming, to effect a chemical reaction between the coloring
matter and the mordant, that is, the tannic acid, and from an insoluble precipitate or
lake in the fibre.
So far this is the ordinary mode of procedure.
The cloth is then passed through a bath containing antimony and maintained below
the degree necessary to effect the desired reaction between the color or lake, and
reagent, that is, the tannic acid and antimony.
The cloth is then subjected to heat outside the bath and the chemical reaction
thoroughly effected between the tannic acid and the antimony, whereby the shade of
the color or lake printed upon the cloth is developed to produce the desired shade and
fixity of color.
In case the coloring matter requires oxidation to produce the desired shade, as for
instance catechu, the color is mixed with a mordant, acetate of chromium, and the
mixture applied to the fabric and a lake formed, as by drying or steaming.
The color is fixed in the cloth but has not been oxidized or developed to bring it
up to the required shade, and in order to effect this result, the cloth is passed through
a bath of oxidizing or developing reagent, such as bichromate of potash, but maintained
cold or substantially cold.
The development of the color or lake is then effected by the subsequent application
of heat outside the bath.
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 : :-
1: That improvement in the art or method of developing lakes or colors fixed on
textile fabrics, which consists, first, in subjecting the fabric containing the lake or
fixed color to a solution of developing reagent at a temperature below the point or
degree necessary to effect the chemical reaction between the lake or fixed color and
the developing reagent, and then exposing the fabric containing the fixed color or
lake and developing reagent to the action of heat to effect the chemical reaction
between the lake or fixed color and developing reagent, substantially as described.
2-That improvement in the art or method of developing lakes or colors fixed in
design on textile fabrics, which consists first in passing the fabric containing the lake

page_text: or color fixed in design through a bath of solution of developing reagent maintained
- at a temperature below the point or degree necessary to effect the chemical reaction
hetween the lake or fixed color and the developing reagent, and then exposing the
fabric containing the fixed color or lake and developing reagent to the 'action of heat
to effect the chemical reaction between the lake and fixed color and developing
reagent, substantially as described.
3-The herein before described method or treatment of lake or colouring matter
in the dyeing or colouring of textile fabric or material.
Dated the 3rd day of June 1890
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.