Improvements in Compounds for Chemical Tanning, and in the Process of Tanning without the Use of Tan-bark or Tannic Acid
Year: 1888

page_text: Date of Application, 7th June, 1888
Specification Accepted, 13th July, 1888
Improvements in Compounds for Chemical Tanning, and in the
Process of Tanning without the Use of Tan-bark or Tannic Acid
I, ELIAS GERSON, of 24 George Street West, in the City of Sydney and Colony of
New South Wales, Tanner and Currier, do hereby declare the nature of my Invention
for "IMPROVEMENTS IN COMPOUNDS FOR CHEMICAL TANNING, AND IN THE PROCESS
OF TANNING WITHOUT THE USE OF TAN-BARK OR TANNIC ACID," and in what
manner the same is to be carried out and performed to be particularly described and
ascertained in ind by the following statement
This Invention relates to an improved compound for use in the tanning of hides,
skins, and animal or gelatinous tissues, without the use of tan-bark or tannic acid,
and it also relates to an improved process for manufacturing leather from such
substances
The object of the invention is to supply a compound by means of which hides, shins,
and animal or gelatinous tissues may be tanned in 1 shorter space of time, and at a
cheaper rate than have been attainable by any of the ordinary methods in which
tannin or infusions of the same are used The invention combines with these advan-
tages of economy in time and saving of expense, the subjecting of the hides, skins, or
tissues to a more complete and effective process of tanning, resulting in the production
of more durable leather of superior waterproof quality, and is an advantage of
secondary importance, it is free from the smell of tan which is so objectionable
characteristic of leathers produced by the action of tan-bark or tannic acid
In carrying out my said invention 1 adopt the same washing, depilatory, and other
processes to which hides and skins are subjected in tanning by tannin compounds, up to
the point at which the said hides and skins are ready for immersion in the tan pits
I then, instead of putting them in the said pits, immerse them in a solution compounded
as follows
-
Sodium Chloride (Salt)-
Common Alum-
Potassium Birchromate-
Acetic Acid
-
Two hundred pounds
Four hundred pounds
Six hundred pounds
One hundred pounds
These quantities of the Sodium Chloride, Common Alum, and Potassium Bichromate
are dissolved together in water prefer ibly heated to nearly boiling point The solution
15 then allowed to cool, when the Acetic Acid is thrown in, and the whole diluted in
about six thousand pounds of cold water This quantity of the compound will be
found sufficient for the treatment at the one operation of about one hundred bullock
hides The potassium bichromate though added for the purpose of imparting a grun
and colour possesses the valuable property of renduring insoluble the gelatinous tissues
of the ludes or shins to which it is applied The material known to tanners as
"Bismarck Brown," may be partially substituted for the potassium bichromate, but I

page_text: prefer that the bichromate alone should be used If, however, the bichromate should
be used in combination with the Bismarck Brown, I prefer th it the mixture should be
in the proportions of five of the former to one of the latter, or there ɩbouts
"
During the time the hides or shins are undergoing treatment in the bath thus com-
pounded, they are several times subjected to the process of "handling" or "slinging'
in the pits, as in the buk process Hides and similar tissues require about three days
treatment in this way, shins require but one day's treatment
After this treatment the hides or skins are taken out of the pits and thoroughly
washed, and are then treated in a second bath which is compounded as follows
Bran
Grun Malt
Water -
Three hundred pounds
Three hundred pounds
Six thousand pounds
-
In this bath the hides or skins are immersed during from one to one and half
days, the exact time being determined by the description of leather to be icted upon,
little time, more or less being sometimes required in treating extremely soft or
extremely hard leathers, thus dress leathers require but one days treatment, whilst
solo leither requires to be treated for one and a half days
Treatment in this bath makes the leather soft and mallow
When tanning sole leather I prefer to scour the leather with vinegar or acetic acid
to which has been added a little water, after it has been treated in the second bath
The currying and dressing of the leather is effected in the ordinary manner as under
the bark process
Although I have specified the quantitics in which the several ingredients forming
the baths used in the process are to be mixed or compounded, and particularised the
strength of the solutions, and fixed the length of time necessary for the treatment of
the hides, skins, and tissues, I wish it to be understood that I do not limit myself to
the specific quantitics or exict proportions of the ingredients or the precise stiengths
of the baths or solutions, or the exact periods of time necessary for the treatment of
Indes or shins in the respective baths, for it is evident that these relative proportions
and times may be varied according to the thickness of the hides or skins to be treated
or the description of the leather to be produced
Having now particularly described and scort uned the nature of my sud
invention und in what manner the same is to be performed I declare that what
I clum 18
1 The compound of Acetic Acid, Sodium, Chloride, Alum and Bichromate of
Potassium substantially in the proportions of one hundred pounds of Acetic Acid,
two hundred pounds Sodium Chloride four hundred pounds common alum and six
hundred pounds Potassium Bichiomite the whole-being-diluted-in-about-six thousand
-pounds of water the said compound being intended for use in the process of tinning
hides, skins and animal or gelatinous tissues subst intilly as described
2 The Compound of Brin ind Grun Milt in the proportions of three hundred
pounds of eich diluted together in about six thousand pounds of water for use in the
process of tinning hides, skins, and animal or gel itinous tissues to soften the leather
ind render it mallow, after the tanning proper has been effected substantially as described
3 The process of tanning hides, skins, and animal or gelatinous tissues with the
Compounds and in the quantities herein set forth subst intilly as described
Dated thus 7th day of June 1888.