Year: 1898

page_text: I, PAUL BERTRAM, Colorist, Nieder-Schönhausen, near Berlin, in the Empire
of Germany, do hereby declare the nature of this invention to be as follows;-
It is known that fur may be dyed by treating on the hair with oxidising agents,
easily oxidizable substances such as p-phenylene diamine, p-amidophenol,
pyrogallol. Likewise deep shades may be produced on fur by a treatment with
logwood and with oxidizing agents, such as potassium chromate.
These processes however are troublesome and their results are to a certain
degree imperfect.
As the oxidation must be effected at a low temperature and by means of weak
oxidizing agents which are not too acid, in order to prevent shrinking and
hardening of the fur, dyeing black or brown is effected very slowly and must be
continued for from 2 to 10 days, according to the oxidizable substances used.
Therefore much time is necessary for drying which must be effected at a low
temperature in order to avoid shrinkage.
In any case the fur hardens and must be softened by a mechanical treatment
or by means of grease.
Moreover, portions of the oxidizable substances are lost, as generally these
substances are put on the hair along with the oxidising agent, and thus oxidation
is partly effected not on the hair.
I have now discovered a new process by which these inconveniences may be
avoided.
This process consists in treating the fur first with sodium hyposulphite and
then with potassium chromate. The furs thus prepared may then be introduced
into a hot solution of the oxidizable substances without any shrinkage taking
place. Dyeing is effected very quickly and without any further addition of
oxidizing agents.
The furs remain soft and may be dried at a high temperature, no further treat-
ment being necessary. The solution of the oxidizable substances may be used
again, as there is no essential loss by oxidation of the dissolved substances. Thus
the oxidizable substance may be completely exhausted. For dyeing fur black,
the process may be as follows.
The fur is treated at a temperature of about 25° C. with a sodium hyposulphite
solution of 20° Bé.; it is then treated with a potassium chromate solution at the
same temperature and with the addition of from 2 to 5 grammes of acid for each
litre.
The furs which are dyed yellow by this treatment are well rinsed and then
passed at about 90° C. through a p-phenylenediamine solution containing from
5 to 10 grammes in 1 litre. After some minutes the fur is dyed a deep black.
By substituting p-amidophenol or pyrogallol for p-phenylene diamine, brown
shades are produced.

page_text: If dye wood extracts, such as logwood, are to be used, the fur must be first
passed through a solution of sodium carbonate before treating it with hyposulphite.
Dated this 25th day of March 1898.
ABEL & IMRAY,
Agents for the Applicant.
Improvements in the Dyeing of Hair and Fur.
3
I, PAUL BERTRAM, Colorist, Nieder-Schönhausen, near Berlin, in the Empire
of Germany, 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:-
It is known that fur may be dyed by treating on the hair with oxidising agents,
easily oxidizable substances such as p-phenylene diamine, p-amidophenol,
pyrogallol. Likewise deep shades may be produced on fur by a treatment with
logwood and with oxidizing agents, such as potassium chromate.
These processes however are troublesome and their results are to a certain
degree imperfect.
As the oxidation must be effected at a low temperature and by means of weak
oxidizing agents which are not too acid, in order to prevent shrinking and
hardening of the fur, dyeing black or brown is effected very slowly and must be
continued for from 2 to 10 days, according to the oxidizable substances used.
Therefore much time is necessary for drying which must be effected at a low
temperature in order to avoid shrinkage.
In any case the fur hardens and must be softened by a mechanical treatment
or by means of grease.
Moreover, portions of the oxidizable substances are lost, as generally these
substances are put on the hair along with the oxidizing agent and thus oxidation
is partly effected not on the hair.
I have now discovered a new process by which these inconveniences may be
avoided.
This process consists in treating the fur first with sodium hyposulphite and
then with potassium chromate.
The furs thus prepared may then be introduced into a hot solution of the
oxidizable substances without any shrinkage taking place. Dyeing is effected
very quickly and without any further addition of oxidizing agents.
The furs remain soft and may be dried at a high temperature, no further treat-
ment being necessary.
The solution of the oxidizable substances may be used again, as there is no
essential loss by oxidation of the dissolved substances. Thus the oxidizable sub-
stance may be completely exhausted. For dyeing fur black, the process may be
as follows.
The fur is treated at a temperature of about 25° C. with a sodium hyposulphite
solution of 200 Bé.; it is then treated with a potassium chromate solution of
50 Bé., at the same temperature and with the addition of from 2 to 5 grammes
of acid for each litre.
The furs which are dyed yellow by this treatment are well rinsed and then
passed at about 90° C. through a p-phenylenediamine solution containing from
5 to 10 grammes in 1 litre.
After some minutes the fur is dyed a deep black.

page_text: By substituting p-amidophenol or pyrogallol for p-phenylenediamine, brown
shades are produced.
If dye wood extracts, such as logwood, are to be used, the fur must be first
passed through a solution of sodium carbonate before treating it with hyposulphite.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is:-
A process for dyeing hair and fur by successive treatment first with solution
of hyposulphite then with solution of chromate and finally either with an easily
oxidisable substance, such as para-phenylenediamine, para-amidophenol, or
pyrogallol or with dyewood extract, substantially as described.
1……. of Nombor 1898
ABEL & IMRAY,
Agents for the Applicant.