Improvements in the Process of Dyeing.
Year: 1893

page_text: United States of America)
Date of Application (in United Kingdom), 28th Sept., 1893
Complete Specification Left, 28th Sept., 1893-Accepted, 30th Dec., 1893
Date of Application (in United Kingdom), 28th Sept., 1893
Complete Specification Left, 28th Sept., 1893-Accepted, 30th Dec., 1893
COMPLETE SPECIFICATION.
Improvements in the Process of Dyeing.
I, OTTO PAUL AMEND, Chemist, of 205 Third Avenue, New York City, United
States of America, 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 especially to the production of a fast mordant on fibrous
substances, and consists of the features hereinafter set forth.
In carrying out my invention I first treat the fibrous substance, whether it be
wool fibre, silk fibre or fibre of some other substance, with a cold solution of
chromic acid in the presence of some other acid that will not produce a secondary
oxidizing effect on the fibre. The resultant of this step of the process is a new
chemical compound which may be described as an insoluble chromate of whatever
fibre may have been so treated. I then subject the fibre to the action of a reducing
agent in solution, as for example, proto-sulphate of iron, monochloride of copper, the
sulphites or bi-sulphites of soda, lime, or any other of the well known reducing
agents. Both of these steps of the process are performed at the ordinary temperature
and no boiling whatever is required. The resultant is a mordant upon the fibre
treated of great value and superior in every way to those produced by the old and
well known processes employing bichromate of potash, tartaric acid, acetate of
chromium or fluoride of chromium etc., all of which require the treated fibre to be
boiled before the mordant is produced.
The mordant produced by my process admits of the formation of any of the
metallic lakes upon the fibre. Compound metallic mordants in combination with
chromium may thus be produced and the results obtained will be found infinitely
superior to anything so far produced. Especially in connection with the alizarine
series are the mordants of my process of great value, and I have thus succeeded in
producing the much sought for copper lake of the alizarine blue.
Again it will be found that logwood and other natural dye-stuffs, as well as
artificial dyes which produce lakes with metallic compounds will produce much
brighter, more permanent and in every way more desirable colors when used in
connection with the mordant of my process than when used with the mordants of the
old and well known processes.
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 :-
The process of producing a mordant on fibrous substances which consists in first,
treating the fibre with a cold solution of free chromic acid in the presence of another
nonoxidizing acid, and second, in treating the thus prepared fibre with a solution
containing one or more metallic or non-metallic reducing agents, whereby the fibre

page_text: is prepared for the reception of a color to be applied by any known process, substan-
tially as set forth.
Dated this 24th day of August 1892.
OTTO PAUL AMEND.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.