Year: 1888

page_text: We JEAN CLAUDE LOUIS DURAND KOECHLIN, DANIEL EDOUARD HUGUENIN
KOECHLIN and ADOLPHE JEAN JAMES D'ANDIRAN KOECHLIN composing the firm of
La Société L. Durand Huguenin et Cie. of Bâle, Switzerland, Manufacturers 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:
Owing to the cost of indigo as a dye, many attempts have been made to compound
it with other substances, but without success, for though at first the composite dyes
may closely imitate indigo, they are so acted on by air, acids, alkalies, chlorine &c. or
by friction that they are not satisfactory.
We after long investigation have arrived at a solution of the problem_by_com-
pounding with indigo the substance Indophenol (supposed formula C₁₁ N, 0)
which was discovered by Koechlin of Loerrach and Witt of Charlottenburg and is
the subject of Patent No. 1373 of 1881.
For producing and applying the composite dye, the process is as follows:-
The two substances are bruised either separately or together and formed into a
paste which is diluted with water and has added to it the various substances called
reducers" such as zinc powder, sodium bisulphite, tin salt, caustic soda or any of
the reducers ordinarily employed. The proportions of the ingredients are approxi-
mately, 1 kilo of dry indophenol in powder,-100 litres of water, 10 kilo. of bruised
indigo in paste compounded in the proportion of 250 grammes of dry indigo to the
litre of water-10 litres of sodium bisulphite at 39° to 40° B.-2 kilo of tin salt (tin
chloride) 2500 kilo of zinc powder. This mixture is agitated for an hour and
then has added to it 8 litres of caustic soda solution at 38° Be. The mixture is again
agitated, and on the following day has added to it twice its volume of cold water.
After vigorous agitation the mixture is allowed to rest for 24 hours or more, until
in fact the liquid becomes clear. It is then applied for dyeing in any of the usual
ways.
If the materials dyed are at once passed through a cold solution of bichromate
of potash in the proportion of 2 grammes of bichromate to a litre of water the color
has its intensity enhanced by 10 to 15 per cent.

page_text: The advantages resulting from the use of the composite dye are
(a) Considerable reduction of cost, three baths of the composite dye give the same
color as five to seven baths of indigo used by itself.
(b) Color as fast as that from indigo alone, withstanding air, friction, contact
of acids, alkalies, chlorine or other discoloring agents.
(c) Facility of application to any animal or vegetable materials that can be dyed by
indigo alone, the operation being in both cases the same.
(d) Economy of time and cost resulting from the fact that whereas indigo deposits
slowly especially when the ferro-calcic solution is employed, there is no need to wait
for the clearing of the composite bath which can be fed during the operation, and the
result of the dyeing can be observed on every piece dyed.
It is to be noted that Indophenol if employed by itself with the same reducers as
those used for indigo, becomes deoxidated with difficulty and does not readily take
on the fibre, it gives moreover a strong violet blue color without much lustre, which
fades to a greyish violet, it holds only moderately to the fibre and therefore it is not
to be recommended as a dye stuff by itself. On the other hand when it is compounded
with indigo and influenced by the same reducers, the mixture behaves exactly as
indigo does, freely taking on the fibre, becoming oxidated in the air as fully and
rapidly as indigo, and strengthening the color without appreciably changing it. The
composite dye, morcover, resists better than indigo the action of discoloring agents
and takes more fully on dead cottons.
When alkaline chromates or analogous agents are applied, the results are the same
with the composite dye as with indigo alone, requiring only a larger proportion of
chromate. The materials on being taken from the composite bath, may be passed
through a bath consisting of 100 litres of cold water, and 2500 kilo of bichromate
of potash or soda, whereby the intensity of the color is enhanced 10 per cent. or more.
Instead of the bichromate, other oxidants may be employed such as calcium hypo-
chlorite, very weak.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1
The use of a composite dye consisting of indophenol and indigo compounded
substantially as described and applied for the purposes herein set forth.
1000
ABEL & IMRAY,
Agents for the Applicants.