An Improved Process of Mordanting Fibres or Fabrics.
Year: 1898

page_text: Date of Application, 5th Apr., 1898-Accepted, 25th June,
1898
COMPLETE SPECIFICATION.
An Improved Process of Mordanting Fibres or Fabrics.
I, FRANCIS JAMES OAKES, of 58, Stone Street, in the City and State of New York,
United States of America, Manufacturer, 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 statements: -
This invention relates to a method for producing a mordant deposit of a
chromium compound on any textile material, using for this purpose commercial
tannic acid and either soluble chromates or bichromates in an acid or neutral bath.
According to my improvement, after appropriate cleansing, the textile material,
whether fibre or fabric, of vegetable or animal origin, or a mixture of
fibres or fabrics of different origins is first placed into a bath consisting
of a solution of commercial tannic acid such as extracts of hemlocks,
chestnut, nut galls, sumac or any other product consisting of tannic acid. The
textile material thus treated is freed from the surplus tannic acid liquor, and is then
passed into a chrome bath when a rapid change takes place and chromium is
deposited in an insoluble form upon the fibre or fabric. Upon this mordanted
material the desired colour is then dyed.
In carrying out my improvement, after suitable cleansing, the fibre or fabric is
immersed in a bath consisting of a solution of tannic acid such as hemlock,
chestnut, nut galls, sumac or pure tannic acid.
I may make a suitable solution by dissolving twenty-five pounds of commercially
pure sumac extract in a sufficient quantity of water to enable me to immerse one
hundred pounds of the fibre or fabric. The temperature of this bath will vary
from an ordinary room temperature to the boiling point of the solution. The
length of time of immersion will also vary from a few minutes to twenty-four
hours, both temperature and time depending upon the nature and texture of the
material under treatment.. The material is now freed from the surplus tannic
acid liquor in a suitable manner as for example, by wringing with the hands or by
nipping between rollers or by subjecting to the action of a centrifugal machine.
Then the fibre or fabric will be subjected to a chrome bath, as for instance, to a
solution consisting of bichromate of soda or potash or ammonia, either with or
without a free acid, or a chromic acid. Upon immersion in this bath a rapid change
takes place and chromium in an insoluble form will be deposited on the fibre.
The temperature of this bath will vary from room temperature to the boiling point
of the solution, and the time from a few minutes to several hours, depending upon
the nature and manufacture of the fibre or fabric. The amount of tannic acid or
of chrome taken will depend upon the depth of the shade to be subsequently
dyed upon the mordanted fibre or fabric. When this process is completed, the
material is washed and is then ready for the actual dyeing operation.
The fibre or fabric thus prepared will be thoroughly and evenly impregnated
with the chromium compound having great affinity for dye-stuffs. For example,
I may wish to produce a black and use for this purpose twenty pounds of logwood
extract dissolved in an amount of boiling water sufficient to cover the one hundred
pounds of textile material, and after immersing the material, boil the same gently
for one hour when it will be dyed a full black.

page_text: As my process is suited alike to animal and vegetable fibre, it is applicable and
of course advantageous for fabrics composed of both.
Having now particularly described and ascertained the nature of my
invention and in what manner the same is to be performed, I declare that what
I claim is:-
The process of mordanting a fibre or fabric consisting in first subjecting it to
a solution of tannic acid, and afterwards subjecting it to a bichromate or chromic
acid bath, thus fitting it for dyeing with any desired color, substantially as
specified.
Dated this 5th day of April 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.