IMPROVEMENTS IN THE PROCESS FOR TANNING TAWED LEATHER
Year: 1884

page_text: I CAESAR KAESTNER of Magdeburg in the German Empire, do hereby declare
the nature of said Invention for "IMPROVEMENTS IN THE PROCESS FOR TANNING
TAWED LEATHER," to be as follows:-
This invention relates to a process for tanning hides and has for its object to
produce in 10 to 16 days leather having the same properties as leather produced
by the ordinary tanning process which requires from 1 to 2 years.
For this purpose I use tawed hides (dressed with alum) which if steeped for a
short time in water would again be transformed into raw hides.
Tawed leather (the production of which by the well known process requires
8 days, is placed into a mixture of alcohol and tannic acid and left in the same
for 8 days at the most. Thereupon the leather is removed from this mixture,
dried, carefully washed with pure water and scraped.
The tanning process proper is now terminated and a well tanned leather is
thus obtained in 16 days at the most, and may be made up into any kind of
leather by the well known process.
By treating tawed leather with tannic acid and water, this mixture produces
immediately a superficial tanning of the leather, but obstructs the cellular tissue in
such manner that the complete and thorough tanning requires a comparatively
long time.
By replacing the water with alcohol, the pores of the leather are not obstructed,
so that the process of tanning is shortened as described above.
The composition of the solution may vary without substantially lengthening the
tanning process.
The composition consists of about 80 per cent of alcohol and 14 per cent of
tannic acid.
The following tannic acids may be cimployed: Tannin, Pikrin, Catechu, and
similar materials, either alone, or mixed together.
Dated this 19th day of August 1884.

page_text: I, CAESAR KAESTNER, of Magdeburg in the German empire, do hereby declare
the nature of my invention for IMPROVEMENTS IN THE PROCESS FOR TANNING
TAWED LEATHER, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :—
This invention relates to a process for tanning hides and has for its object to 5
produce in 10 to 16 days leather having the same properties as that produced by
the ordinary tanning process which requires from 1 to 2 years.
For this purpose I use tawed hides (dressed with alum) which, if steeped for
n-short time in water, would again be transformed into raw hides.
Tawed leather (the production of which by the well known process requires 1
8 days), is placed into-a-mixture-of-alcohol and tannie-acid, and left in the same
for a period not exceeding 8 days. Thereupon-the-leather-is-removed frour this-
mixture, dried, carefully washed with pure water, and scraped.
The tanning process proper is now terminated, and a well tanned leather is thus
obtained-in-16-days at the most, which may be made up into various descriptions 1
of leather by well known processes.
-
If tawed leather-is-treated with tannic acid and water, this-mixture-produces
immediately a superficial tanning of tlie leather, but obstructs. the cellular tissue
in such manner that the completo and thorough tanning requires a comparatively.
long time.
By replacing the water with alcohol, the pores of the leather are not obstructed,-
8 that the process of tanning is shortened as described above.
The composition of the solution may vary without substantially lengthening the
tanning process, but preferably I take about 80 per cent of alcohol and 14 per cent
of tannic acid.
The following tannic acids may be employed: Tannin, Pikrin, Catechu, and
similar materials, either alone or mixed together.
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,
The process of tanning tawed leather, which consists in subjecting the leather to
a mixture of alcohol and tannic acid, substantially as described.
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יה ניר
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