AN IMPROVED PROCESS OF TANNING HIDES OR SKINS to be as follows:
Year: 1884

page_text: I JOHN SALAMON, of Wennington, in the County of Essex, Gentleman do
hereby declare the nature of said invention for "AN IMPROVED PROCESS OF
TANNING HIDES OR SKINS to be as follows:-
"
My invention relates to an improved process of tanning bides or skins by means
of organic alkalies or their derivatives, and is designed to effect this operation with
rapidity and without swelling the hides or skins.
Weak acids have usually been employed in tanneries for swelling the hides or
skins, with the sole object of enabling the latter to absorb the tannin, because the
more a hide or skin is swelled, the greater the avidity with which it imbibes or
absorbs the tannin.
I am aware that there are processes whereby hides or skins can be tanned with
very little delay; I will cite only that of Seguin, who has tanned hides or sking
very rapidly by means of sulphuric acid, which he employed at 1/800; but these
means are too active and remove from the leather all its good quality by dispersing
or displacing the fibres of the hides or skins, which fibres do not resume their
proper position during the drying; hence the production of spongy or porous
leather, or leather of bad quality.
By my improved process which is carried into effect without swelling the
leather, I tan the hides or skins just after they have been soaked in water, that
is to say, without separation or displacement of the fibres.
I employ, for this purpose, organic alkalies or their derivatives, but I prefer
aniline, which coagulates the albumenoids with great facility; but as aniline is
only slightly soluble in water, I employ one of its derivatives viz-the aniline
orange yellow a tinctorial substance soluble in water.
I employ this substance in the following manner in the proportions named, that
is to say For bides or skins laid in pits, for liquor-tanning, for tanning by means
of extracts or of concentrated tanning liquor, and in fact for all kinds of tanning
whatever be the tanning substance employed, the quantity of aniline or its deriva-
tives required is the same, viz;-One gramme per twenty kilogrammes of-hides or
skins. But by increasing the quantity of alkali employed I can effect the tanning
more rapidly, if desired.

page_text: The quantity of bark or tan to be employed for perfect tanning is first placed in
direct contact with the hide or skin, without the risk, usual in such cases, of the
fatal superficial combination of the tannin and protein substance, which, immedi-
ately becoming impermeable, prevents the active liquor from penetrating to the
centre. The hide or skin being coagulated by an organic alkali or one of its
derivatives, there is no risk of this combination taking place. In fact a hide or
skin coagulated under these conditions becomes porous immediately.
It is only necessary, therefore, to dissolve in the water of imbibition one gramme
of organic alkali or its derivatives for every twenty kilogrammes of hides or skins
to be tanned.
By my process fine calf is tanned in fifteen days; medium calf in twenty days;
strong calf in thirty days; and cow and ox hide in one hundred and twenty days.
But I can effect the tanning more rapidly with the extracts.
HASELTINE, LAKE & Co.,
For the Applicant.

page_text: I, JOHN SALAMON, of Wennington, in the County of Essex, Gentleman, do
hereby declare the nature of my invention for "AN IMPROVED PROCESS OF
TANNING HIDES OR SKINS 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 to the utilization of organic alkalies or their derivatives
in the tanning of hides or skins, and comprises an improved process whereby the
tanning is effected very rapidly and without swelling the hides or skins.
It has been customary heretofore, in tanneries, to employ weak acids for swelling
the hides or skins, with the sole object of enabling them to absorb the tannin,
because the more a hide or skin is swelled, the greater will be the avidity with
which it imbibes or absorbs the tannin.
800
There are various known processes whereby hides or skins can be tanned
with very little delay; for example, that of Seguin, whereby hides or skins have
been tauned very rapidly by the employment of sulphuric acid at 1/coo for swelling
the hides or skins; but this treatment tends to impair or deteriorate the quality of
the leather by spreading or displacing the fibres of the hides or skins, which fibres
do not resume their proper position during the drying; hence the production of
spongy or porous leather or leather of bad quality.
By my improved process, which is carried into effect without swelling the hides
or skins, I tan the latter in the condition in which they are left after they have
been soaked in water, that is to say, without separation or displacement of the
fibres.
I employ, for this purpose, organic alkalies or their derivatives, such as aniline,
which coagulates the albumenoids with great facility; but, as aniline is only
slightly soluble in water, I prefer to employ one of its derivatives, viz :--the aniline
orange yellow, a tinctorial substance soluble in water.
For hides or skins laid in pits, for liquor-tanning, or for tanning by means of
extracts or by means of concentrated tanning-liquor, in fact for all kinds of tanning
whatever be the tanning substance employed, the quantity of the organic alkali or
its derivative, which should be used in the process, is the same, viz ;--about one
gramme per twenty kilogrammes of hides or skins. But, by increasing the quantity
of alkali employed, I can effect the tanning more rapidly, if desired.
I dissolve the organic alkali or the derivative thereof in the water of imbibition.
The quantity of bark or tan which is to be employed for the complete tanning is
placed in direct contact with the hide or skin. The said hide or skin being coagu-
lated by the organic alkali or derivative thereof, there is no liability to the
injurious superficial combination of the tannin and protein substance, which usually
takes place and which immediately renders the bide or skin impermeable and
prevents the active liquor from penetrating to the centre thereof. A hide or skin
coagulated under the conditions above named becomes porous immediately.
By my process fine calf can be tanned in fifteen days, medium calf in twenty
days, strong calf in thirty days and cow and ox hide in one hundred and
twenty days. But I can effect the tanning more rapidly with the extracts above
referred to.
I can employ, for the purpose of my invention, all kinds of organic alkalies
(whether natural or artificial, liquid, solid, or volatile) or their derivatives.
I sometimes take the hides or skins in the condition in which they are left after
they have been soaked in water, and immerse them in a tannic solution prepared
as above described. After immersion for one hour, I press or squeeze them

page_text: between cylinders or rollers to free them from the water which they contain.
I then again immerse them in the said tannic solution, so that the quantity of
water expelled is immediately replaced by tannin. I repeat this operation until
the tanning is accomplished. By these means I can complete the tanning in a few
hours. .
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 above described improved process of tanning hides or skins, in which
process I employ aniline or aniline orange yellow, or other organic alkali or
derivative thereof, as, and for the purpose, specified.
HASELTINE, LAKE & Co.,
.For the Applicant.