AN IMPROVED TREATMENT FOR SOFTENING, UNHAIRING, PURING, UNGREASING AND PRESERVING HIDES AND SKINS
Year: 1882

page_text: LETTERS PATENT to Alexander Melville Clark of the firm of A M and
W Clark of 53, Chancery Lane, in the County of Middlesex, Patent Agents,
for an invention of AN IMPROVED TREATMENT FOR SOFTENING, UNHAIRING,
PURING, UNGREASING AND PRESERVING HIDES AND SKINS A communication
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 10th May 1882.
ALEXANDER MELVILLE CLARK of the firm of A. M. &. W. Clark of 53 Chancery
Lane in the County of Middlesex, Patent Agents, "AN IMPROVED TREATMENT
FOR SOFTENING, UNHAIRING, PURING, UNGREASING AND PRESERVING HIDES AND
SKINS." [A communication from abroad by Jules Louis Moret, of Paris, France.]
This Invention relates to improvements on the Inventions for which Letters
Patent were granted to me respectively dated September 3rd 1880 No 3583, and
March 23rd 1881 No 1287, and it has for its object to enable hides and skins of
all kinds to be immediately unhaired and prepared for tanning or to be preserved
in a fresh state for a limited time, or in a dried state for an indefinite length of
time for transport or storage without danger of dry cracking, putrefaction, and
the attacks of vermin and insects and to enable the hides and skins to be at once
unhaired after being so preserved without further treatment than a few hours
steeping in pure water. It has also for its object to effect the ungreasing of sheep
and other skins and the softening of china hides, East India kips and other dried
hides and skins.
This improved treatment of hides and skins with a view to immediate unhairing
is essentially inoffensive in its character and it comprises two operations, viz―
1st. The unhairing process proper, and
2nd. What is termed a scudding puring and ungreasing operation (in which
however no offensive "bate" is used) to remove the undergrowth, down, or
remaining short hair left after the first operation.
The first of these operations may be performed in either of two ways (except
when sheep skins are being treated) viz-by immersion, or by application with a

page_text: In
brush, the strength of the vat or composition depending on the mode of use.
the case of sheep skins the second alternative method only is employed, viz-
application of the composition with a brush in order to avoid injury to the wool.
The composition of this Invention from which the solutions or liquors employed
in these two above mentioned operations, are prepared, consists of a solution of
American potash or caustic potash, or the potash of the "suint" or "yolk" of the
wool itself at the proper temperature with the addition of 1/10 to 2/10 of a kilo-
gramme of red orpiment or realgar in powder to each kilogramme of potash and
with or without the further addition of 2/10 3/10 or 1/10 of a kilogramme of lime for
each kilogramme of potash, the proportions depending on the kind of potash used
and on the manner in which the composition is to be applied or used. The
composition is allowed to settle and the clear liquor decanted off for use in either
of the following ways.
1st. For application with a brush to the flesh side of the hide or skin for the
purpose of unhairing the same, the composition is reduced to the proper strength
by the addition of a certain quantity of water.
2nd To form a vat or bath in which the hides are to be immersed as a first
operation for the purpose of unhairing them, or as a second operation for the
purpose of removing the undergrowth or down remaining after the first operation,
and for the purpose of puring and ungreasing the composition is still more diluted
with water. In either case for the purposes of this second or so called scudding
puring and ungreasing operation a greater proportion of red orpiment or realgar
and lime is used than for the first or unhairing operation.
For the purpose of preserving hides and skins for transport and preparing them
for unhairing at any subsequent time by a simple steeping in water, the proportion
of potash is increased and 1 may or may not also add a salt known as preservative
salt, or merely a small proportion of salicylate of soda, the composition being in
this case applied either with a brush or by immersion, the hides or skins being
afterwards dried. In this state they may be preserved for an indefinite period
and may be at any subsequent time very quickly restored to their original green
and natural condition by simply steeping them for about 12 hours in water. They
may then be unhaired and treated in the same way as fresh skins. The water in
which the hides and skins have been so steeped serves for preparing the baths or
vats used in the first and second operations. This mode of preservation forms an
admirable substitute for the salting treatment hitherto generally used for preserving
hides and renders unnecessary the injurious liming or other treatment for unhairing.
The softening of dried hides is effected by steeping in a very weak solution of
either of the above mentioned compositions.
I would remark that I do not restrict myself to the above mentioned proportions
of the ingredients but reserve the option of varying the same according to the
kind of hides or skins treated and I may employ the operations herein described
separately. or in combination with one another, or with other known processes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
10th November 1882.
ALEXANDER MELVILLE CLARK of the Firm of A, M, and W, Clark of 53 Chancery
"AN IMPROVED TREATMENT
Lane in the County of Middlesex Patent Agents
FOR SOFTENING, UNHAIRING, PURING, UNGREASING AND PRESERVING HIDES AND
SKINS."
A communication from abroad by Jules Louis Moret of Paris, France.
This Invention relates to improvements which are in part based upon, or
connected with, the Inventions for which Letters Patent were granted to me,
respectively dated September 3rd 1880 No. 3583, and March 23rd 1881 No 1287.
It has for its object to enable hides and skins of all kinds to be immediately
unhaired and prepared for tanning, or to be preserved in a fresh state for a limited
time, or in a dried state for any requisite length of time for transport or storage.
It obviates the difficulties which have hitherto existed in treating skins or hides,
arising from danger of dry cracking, or putrefaction, or from the attacks of vermin
and insects, and it further enables the hides and skins to be at once unhaired after
being so preserved, without further treatment other than a few hours steeping in
pure water.
It has also for its object to effect the ungreasing of sheep and other
skins, and the softening of China hides, East India kips, and other dried hides and
skins by a more efficient and economical method than any hitherto employed or
endeavoured to be applied for like purposes.
This improved treatment of hides and skins with a view to immediate unhairing
is essentially inoffensive in its character, and it comprises two operations, viz :—
(1) The unbairing process proper, and (2) What is termed a scudding, puring, and
" bate
ungreasing operation, in which however offensive
is dispensed with,
thereby effecting a great improvement over the old processes, while the under-
growth down, or remaining short hair, left after the first operation, is removed
with success, and in such a state that it is fit to be used for various purposes as
what may be termed raw material.
The first of these operations may be performed in either of two ways (except
when sheep skins are being treated) viz-by immersion, or by application with a
brush or mop, the strength of the composition or chemical agent employed being
adapted in the respective cases to the mode of use. In the case of sheep skins the
second alternative method only is employed, viz-application of the composition,
with a brush or mop on the flesh side in order to avoid injury to the wool.
37
The composition forming the solutions or liquors employed in these two above
mentioned operations according to this Invention, is prepared in the following
way. A solution of what is known commonly as American potash, or of ordinary
yolk
caustic potash (or of potash which may be obtained from the "suint" or
of the wool itself, as described in the specification of Letters Patent dated the
3rd September 1880, No. 3583) is made of the required strength and is raised to a
temperature of from about 180° to 200 F. I then add (stirring the composition
well meanwhile by means or an agitator) about 2 oz to 31, oz of realgar in powder
to each pound (avoirdupois) of potash employed together with or without the
further addition of 3 oz, 5 oz, or 7 oz of quick lime for each pound of potash, the
proportions depending on the kind of potash used, and on the manner in which
the composition is to be applied or used,
The quick lime may be omitted when the potash is found to be sufficiently
strongly caustic without adding the lime, and it is to be noted that the employment
of quick lime in the composition used according to this Invention is limited to

page_text: those cases where it is required in order to ensure that the potash is sufficiently
caustic, and only so much should be used in any case as may be required to effect
this object. By observing this precaution and following the method of treatment
of this Invention, the inconveniences arising from stench caused by using what is
termed "bate or otherwise which have been hitherto experienced in the ordinary
treatment of hides and skins are obviated, and this is one of the great advantages
obtained by the use of this improved process of treatment.
"
The composition is allowed to settle and the clear liquor decanted off and is in
that state employed with great advantage in either of the following ways.
1st. For application with a brush or mop to the flesh side of the hide or skin for
the purpose of unhairing the same, the composition is reduced to the proper
strength by the addition of the required quantity of water. The strength of the
decanted composition for light skins is to be froin about 8° to 14° Beaumé and for
heavy skins and hides from about 12° to 14° Beaumé.
2nd. To form a vat or bath in which the hides and skins are to be immersed
(for the purpose of removing the undergrowth or down, for scudding, puring, and
ungreasing) the composition is still more diluted with water, the strength in this
case being from about 1° to 4° according to the nature of the skin.
To form a vat or bath in which the hides and skins are to be immersed as a first
operation for the purpose of unhairing them, I wash with water two or more times
until exhausted, the residue left after drawing off the clear liquor in preparing the
above mentioned composition, stir up well, let settle, and draw off clear, and with
these clear washing waters added together, I make a saturated solution of potash.
I reduce this with water to from /° to 8° Beaumé.
Instead of washing the residue left from the preparation of a previous com-
position, I may make the vat or bath at once in the same way as above described
for the composition itself, the proportions in this case being 1 oz (more or less) of
realgar and 2 oz, 4 oz, or 5 oz of quicklime to each pound of potash employed. The
quick lime may however be dispensed with in this case also when the potash is
strongly caustified.
For the purpose of preserving hides and skins for transport, and preparing them
for unhairing at any subsequent time by a simple steeping in water, I use a
solution of American potash at 8° to 15° with the addition of 30 grains (or more)
of salicylate of soda or other preservative salt to every cwt of composition at 10° B,
the composition being in this case applied either with a brush or mop or by
immersion, the hides or skins being left in this state or dried, according as they
are to be kept a greater or less length of time. In the dry preserved state they
may be kept for an indefinite period and may be at any subsequent time restored
to their original green and natural condition by simply steeping them for about
12 hours in water, when the hair and scud may be removed without further
treatment with chemical agents. The water in which the preserved hides and
skins have been so steeped, serves for preparing the baths or vats used in the first
and second operations. This mode of preservation forms an admirable substitute
for the salting treatment hitherto generally used for preserving hides and renders
unnecessary the injurious liming or other treatment for unhairing. The quality of
the leather obtained from hides thus preserved by this improved process, will be
found to be superior to that of hides treated in the ordinary way.
The softening of China hides, East India kips, and other dried hides is effect.ed
by steeping in a very weak solution (2° Beaume) of either of the above
mentioned compositions.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is.
1st. The herein described method of effecting by means of the agents referred to,
the unhairing of hides or skins by an economical and efficient, and at the same!
time, comparatively inoffensive process, substantially as set forth.
2nd. The herein described method of effecting the successive operations of

page_text: unhairing, scudding, puring, and ungreasing hides and skins, substantially in the
manner and by means of the Agents herein specified.
3rd. The use of the chemical agents employed in the above mentioned method
of treatment combined with a salicylate or other preservative salt for treating and
preserving hides and skins, and the production of hides in a preserved state
ready for being unhaired after a simple steeping process, substantially as herein
described.
In Witness whereof I the said Alexander Melville Clark have hereunto set
set my hand and seal this tenth day of November, A.D. 1882.