Improvements relating to the Treatment of Hides and Skins.
Year: 1893

page_text: Date of Application, 4th Feb., 1893
Complete Specification Left, 1st Nov., 1893-Accepted, 2nd Dec., 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by ADOLPHE JACOB STRAUSS, of 118, Rue du
Temple, Paris, in the Republic of France, Dealer in Hides and Leather.]
Improvements relating to the Treatment of Hides and Skins.
I. HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby declare
the nature of this invention to be as follows:-
This invention relates to a process of transforming the tanned goat, sheep, calf
and other hides into tawed hides so as to combine the suppleness and other qualities
imparted to the hides by the tawing with the strength obtained by tanning.
The invention consists essentially in taking a hide which has already tanned, that
is to say converted into leather, an imputrescible compact body composed of tannin
combined with the animal material in an indissoluble manner, and untanning this
hide in order, if not to bring it back to its primitive state, to cleanse it from
injurious material with which it had been impregnated at the time of the tanning,
then treating it by a series of operations some of which are similar to those of
ordinary tawing, while others are different as will be seen from the following
description of the new process.
As regards the manipulations and the proportions of the compounds and
ingredients employed I will assume that a dozen goat skins which have already
been tanned are to be treated. The following are the operations in the order in
which they must be effected to realize the desired result:-
(1) I commence by working the hides with tepid water for about two hours in a
turning wheel or drum.
(2) I continue this working, but only for half an hour, in a bath composed of
pure potash, in the proportion of 30 grammes for 60 litres of water.
(3) When the hides have been removed from this bath they are soaked for five
minutes in very weak solution of hydrochloric acid which has the effect of
neutralizing the potash.
By these first three operations, which I call preliminary operations, the hides
are perfectly cleansed from injurious tanning materials, but although the tannin is
discharged they preserve the semi-compact and imputrescible state, that is to say
the properties and advantages of the tanning which they had undergone.
I then proceed with the treatment under new conditions which will now be
explained.
(4) In a suitable receptacle 1 prepare a solution of quebracho (wood from
Brazil and La Plata containing much tannin) in the proportion of 30 litres of
pulverized quebracho to 150 litres of water. The maceration and extraction are
promoted by heating with the aid of a boiling nozzle or the like.
This solution of quebracho serves as a base for the following tawing bath:
Solution of quebracho
-
15 litres

page_text: are placed one upon the other flesh against flesh on a marble table where they are
rubbed with a stone generally consisting of grit, such as is used by tanners.
(6) The hides thus united and rubbed on both sides are then brushed over
with an ammoniacal solution composed of 100 grammes of ammonia and 15 litres of
water.
(7) They are then impregnated with a solution of campeachy wood, which is
prepared by boiling for 2 hours 16 kilogrammes of wood in 110 litres of water.
This operation is repeated several times. The hides still united are plunged in a
vat provided with a false bottom which contains a solution of campeachy; they
are then withdrawn in order to be put on a table, this being done several times so
as to oxidize the solution of campeachy by the air. I stop when the colour has
attained a deep chestnut.
(8) Then I lay the united hides upon a curved table, brush them with a solution
of sulphate of iron and sulphate of copper in the proportion of 60 grammes
and 15 litres of water.
(9) The hides are then put again in a pit containing another bath of campeachy
(8 litres of campeachy extract and 100 litres of water), whereupon they are
separated and rinsed one by one in pure water.
(10) The last operation is the airing of the separated hides; they are placed on
a table and rubbed upon the hair side with round edged tool, which has the effect of
causing the veins to disappear and rendering the hide perfect, smooth and flat.
I now proceed with the finishing operations, which are known in tawing and need
not be enumerated.
The hides obtained by the process hereinbefore described combine the qualities
of tanning and of the new treatment which forms the subject of this invention.
The hides have preserved the compact and imputrescible state of leather, but have
lost its stiffness and they are cleansed from the fatty and other foreign materials
which have been introduced at the time of the tanning. After the new treatinent
they have acquired the qualities of tawed hides with the advantage of being
stronger, less liable to crack and less expensive.
Dated this 4th day of February 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements relating to the Treatment of Hides and Skins.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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:-
This invention relates to a process of transforming tanned goat, sheep, calf and
other hides into tawed hides so as to combine the suppleness and other qualities
imparted to the hides by tawing with the strength obtained by tanning.
The invention consists essentially in taking a hide which has already been tanned,
that is to say, converted into leather, an imputrescible compact body, composed of
tannin combined with the animal material in an indissoluble manner, and untanning
this hide in order, if not to bring it back to its primitive state, to cleanse it from
injurious material with which it had been impregnated at the time of the tanning,
then treating it by a series of operations some of which are similar to those of
ordinary tawing, while others are different as will be hereinafter seen from the
following description of the improved process.
As regards the manipulation and the proportions of the compounds and ingredients
employed I will assume that a dozen goat skins which have already been tanned,

page_text: are to be treated. The following are the operations in the order in which they
must be effected to realize the desired result:-
(1) I commence by working the hides with tepid water for about two hours in a
turning wheel or drum.
(2) I continue this working, but only for half an hour, in a bath composed of
pure potash, in the proportion of 30 grammes to 60 litres of water.
(3) When the hides have been removed from this bath they are soaked for five
minutes in a very weak solution of hydrochloric acid which has the effect of
neutralizing the potash.
By these first three operations, which I call the preliminary operations, the hides
are perfectly cleansed from injurious tanning materials, but although the tannin
is discharged they preserve the semi-compact and imputrescible state, that is
to say, the properties and advantages of the tauning process which they had
undergone.
I then proceed with the treatment under new conditions which will now be
explained.
(4) In a suitable receptacle I prepare the solution of quebracho (wood from
Brazil and La Plata containing much tannin) in the proportion of 30 litres of
pulverized quebracho to 150 litres of water. Maceration and extraction are
promoted by heating with the aid of a steam jet, or the like.
This solution of quebracho serves as a base for the following tawing bath :
the whole being diluted and well mixed in 30 litres of tepid water.
Into this bath I plunge the hides which are pounded and worked about therein
for from 2 to 3 hours.
(5) On leaving this bath the bides are taken in pairs, that is to say, two hides
are placed one upon the other, flesh against flesh on a marble table where they are
rubbed with a stone, generally consisting of grit, such as is used by tanners.
(6) The hides thus arranged and rubbed on both sides are then brushed over
with an ammoniacal solution, composed of 100 grammes of ammonia and 15 litres
of water.
(7) They are then impregnated with a solution of campeachy wood, which
solution is prepared by boiling for 2 hours, 16 kilogrammes of the wood in 110 litres
of water.
This operation is repeated several times. The hides still together are plunged
in a vat provided with a false bottom, which contains a solution of campeachy;
they are then withdrawn in order to be placed on a table, this being done several
times so as to oxidize the solution of campeachy by action of the air.
operation when the colour has attained a deep chestnut.
I stop this
(8) Then I lay the said hides, still together, upon a curved table, and brush
them with a solution of sulphate of iron and sulphate of copper in the proportion
of 60 grammes and 15 litres of water.
(9) The hides are then again placed in a pit containing another bath of
campeachy (8 litres of campeachy extract to 100 litres of water), and afterwards
separated and rinsed one by one in pure water.
(10) The last operation is the airing of the separated hides; the said hides
are placed on a table and rubbed upon the hair side with round edged tool,
which has the effect of causing the veins to disappear and rendering the hide
perfectly smooth and flat.
The final operations which are known in tawing need not be herein described.
The hides obtained by the process herein before described combine the qualities
of tanning and of the new treatment which forms the subject of this invention.

page_text: The hides have preserved the compact and imputrescible state of leather, but have
lost its stiffness and they are cleansed from the fatty and other foreign materials
which have been introduced at the time of the tanning. After the new treatment
they have acquired the qualities of tawed hides with the advantage of being
stronger, less liable to crack and less expensive.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :—
First. The improved process of transforming tanned hides into tawed hides,
consisting in the untanning of the hides previously tanned or the cleansing of
the said bides by the aid of the three preliminary operations hereinbefore
described.
Second. The transformation of the cleansed hides into tawed hides by the
combination of the operations hereinbefore described and especially those which
consist in the immersion of the hides in the quebracho bath, the brushing of the
paired hides with an ammoniacal solution, and in the successive steeping of the said
hides in a solution of campeachy, then in a solution of sulphate of iron and sulphate
of copper, in the manner substantially hereinbefore set forth.
Dated this 1st day of November 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant..