IMPROVEMENTS IN UNHAIRING HIDES OR SKINS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office of
the Commissioners of Patents on the 21st July 1882. Communicated to
him from abroad by Bernard Etcheverry of Paris in the Republic of France.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN UNHAIRING HIDES OR SKINS" a communication
to me from abroad by Bernard Etcheverry of Paris in the Republic of France.
This Invention relating to unhairing hides or skins consists essentially of
submitting the hides or skins to the action of hot water in the manner herein-
after described in place of effecting the description by means of lime as heretofore
practised.
The operation of unhairing hides or skins is usually performed by arranging the
hides or skins in pits or tanks and covering them with a milk of lime. This
method involves the occupation of a large space and is tedious and laborious and
the lime used to remove the hair and wool also acts prejudicially on the hides or
skins and seriously affects the quality of the product.
Moreover the hides or skins prepared in this manner do not take the tannin
well because their pores are contracted and also owing to the immediate formation
of tannate of lime.
All these disadvantages are obviated according to this invention by subjecting
the hides or skins to the action of water heated to about 80 degrees Centigrade or
less than boiling heat and dispensing with the lime heretofore employed.
In carrying out this Invention the hides or skins are first washed with cold
water when they are received from the slaughterers and any fragments of flesh still
adhering are removed by the aid of a suitable tool. The hides or skins are then
immersed in water contained in suitable receptacles and heated to about eighty
degrees Centigrade or preferably maintained at a temperature just below the
boiling point of water. Care must be taken to agitate the hides or skins while in™
the water where they are allowed to remain for the space of about one minute; this
time will necessarily vary according to the size and nature of the materials under
treatment but is always very short.
When taken out of the water the skin is placed on a block or table and the
whole of the hair or wool may then be easily and expeditiously removed by means
of a stone rubber or other suitable tool.

page_text: After this operation the leather is passed through the usual bath and undergoes
the regular processes of tanning in the ordinary manner but under much more
favourable conditions than when it has been unhaired by the ordinary treatinent.
Leather treated as herein before described retains all its natural strength and
elasticity the pores are opened by the action of the hot water so that it is in the
best possible condition for absorbing the acting principle of the tannin whereby a
leather is obtained of fine quality good weight and very superior texture to that
which has been subjected to the action of lime.
The cost of the apparatus and the time and labour required are also reduced
and the putrid exhalations from the lime pits are avoided by employing the
improved treatment hereinbefore described.