Improvements in Dyeing.
Year: 1896

page_text: Improvements in Dyeing.
I, ELIZA JESSIE STEWART, of 74 Abingdon Road, Kensington, in the County of
London, Gentlewoman, do hereby declare the nature of the invention to be as
follows:-
My Invention relates to an improved process for the production of the colour
known as "Khaki" and more particularly to the dyeing of fabrics such as the
drill worn by the Military in India and other Countries within the tropics.
The climatic conditions to which such goods are exposed are such as to cause
any but the fastest colours to fade rapidly and so great is the difficulty in obtaining
a dye of sufficient permanence that the manufacture of khaki goods is almost
entirely confined to a very few firms and the price is consequently high.
Now according to my invention such goods may be dyed of a good khaki colour
which is very permanent and well suited for the purpose required and at a very
moderate cost.
In carrying out my Invention, I employ a vegetable product not hitherto known
as a dye Stuff, and treat the articles to be dyed therewith, or with a compound
thereof, in such manner that the colour produced may be reinforced or modified
and at the same time rendered fast and permanent.
The vegetable product which I have discovered to be useful for this purpose is
the outer shell or husk of the pods of the Cotton Plant which have hitherto been
regarded as a waste product of little or no value being occasionally used as an
inferior kind of fodder.
The colouring matter is extracted from the cotton pod by boiling in water and
decanting; otherwise, in place of the extract obtained as above, I employ an extract
made in like manner from the bark of the Babool tree (which substance has been
used as a dye, but has never been made to yield a permanent khaki dye; or
alternatively, Catechu may likewise be prepared in solution and used for the same
purpose. This substance although well known as a dye has not hitherto been
known to be capable of yielding a permanent khaki dye such as that resulting
from its treatment according to my process.
In order to use any of the substances above mentioned for dyeing in fixed colours
I heat it and add myrobalans and sulphate or other like salt of iron and in this
mixture either hot or boiling I steep the fabric to be dyed and then leave it to
soak for some hours after which I pass it through or rinse it in water and then
either dry it or not according to circumstances.
After this I steep it for some time in a, preferably warm, solution of Bichromate
of Potash and then rinse thoroughly and dry and finish. The colour is then
effectually fixed.
Doted the 13th day of November 1896
NEWNHAM BROWNE,
Agent for the Applicant.

page_text: I, ELIZA JESSIE STEWART, of 74 Abingdon Road, London, Gentlewoman, 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:-
My Invention relates to improvements in dyeing and which improvements are
specially useful in the production of certain fast shades known as Khaki and in
dyeing fabrics in fast colours in browns drabs and greenish yellows.
I have discovered that if the outer shells or husks of the pods of the Cotton Plant
which have hitherto been regarded as a waste product be extracted by boiling in
water and decanting and straining the resulting solution, that a clear brown liquid
is obtained which on evaporation at a slow rate leaves a glossy brown residue.
This clear liquid or a solution of the residue in water forms a most valuable dye
stuff not unlike Catechu in its properties for which it may in many cases be used
as a substitute and which is easily oxidised and rendered insoluble by a bath of
bichromate of potash or by mere exposure to the air. A convenient strength of
extract is obtained by boiling 1 lb. of pods in 16 gallons of water and carefully
straining the resulting brown liquid, an extract of about this strength will give
good results though the final colour will be deeper the stronger this extract is
made. The colouring matter can be obtained in a pure state by evaporating a
strong extract of the pods to dryness and in this condition is more portable than
the pods are and if used in this form it must be redissolved in the requisite quantity
of hot water.
To cause the colour to penetrate the fibre of the material to be dyed I may use
a bath of myrobalans as a mordant and to vary the colour produced I may add
salts of iron or copper or other salts to the bath as is well understood in the working
of astringent dyes.
In order to produce the very fast and permanent dye of the peculiar shade known
as Khaki I proceed as follows:-To each gallon of the hot or boiling solution of
the extract obtained from cotton pods as above described I add about 4 drachms
of myrobalans and about 1 graius of sulphate of iron or other like salt of iron
(the particular quantity of the salt depending on the shade of Khaki required,
but the more iron is used the greener will be the final shade) and in the bath either
hot or boiling I steep the fabric to be dyed and then leave it to soak for some
hours after which I pass it through or rinse it in water and then either dry it or
not. The fabric is then steeped in a warm bath of a weak solution of bichromate
of potash after which it is thoroughly washed dried and finished. I have also
discovered that in the above process the cotton pod extract may be replaced by
catechu or by extract prepared in like manner from the bark of the Babool Tree
and if the same process is carried out a very fast Khaki dye will be produced and
if catechu is employed a bath of 20 grains of catechu to the gallon will give good
results.
The cotton pod extract is of great value as a colouring matter in that it is
produced from a waste product and is therefore very cheap and easy to obtain its
shades are easily modified from browns to yellows and yellowish greens by the
use of suitable salts, it produces a faster dye than even catechu and fabrics
steeped in a weak hot solution of the extract and then left to oxidise in the air
without further treatment will be found to have taken a colour varying from
pinkish brown to brown which is unaltered by washing with soap and even boiling.
As a further instance of the way in which the cotton pod extract may be used

page_text: instead of catechu it will be found that a bath containing 1 oz. of pods and
10 grains of acetate of copper to the gallon used hot and with a subsequent
bichromate of potash bath will dye a fast brown shade or with nitrate or sulphate
of copper (instead of acetate) a yellowish brown shade will be obtained this of
course is merely the substitution of the extract for catechu in a well known
catechu process.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. In dyeing the employment of cotton pod extract made as herein before
as described.
2. The improved process for the production of a Khaki dye consisting of the
use of a bath of cotton pod extract a salt of iron and myrobalans with a subsequent
bath of bichromate of potash or other similar oxidising agent substantially as
described.
3. The improved process for the production of a Khaki dye consisting of the
use of a bath of catechu or babool bark extract a salt of iron and myrobalans with
a subsequent bath of bichromate of potash or other similar oxidising agent
substantially as described.
Dated the 2ith day of July 1807