Swelling or Puffing the same.
Year: 1888

page_text: Date of Application, 16th Oct., 1888
Specification Accepted, 16th Nov., 1888
Swelling or Puffing the same.
I, JULIUS HAUFF, of Fenerbach, near Stattgart, Wurtembergh, Germany,
Manufacturer, 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 novel means of removing lime from skins, kips, and
hides by means of a watery solution of creosotic acid.
Hitherto, no process has been made known by means of which, lime can be
effectually removed from skins, kips, or hides, which meet all the requirements of
practice. The nearest approach in this direction is the treatment by means of
muriatic acid but its general use offers a great many dangers which prevents its being
properly handled or manipulated.
With muriatic acid rank first of all, certain organic acids, which owe their origin
to an acid fermentation or putrid decomposition. Their action upon the substances
under treatment and the extension to the latter of the process of decomposition which
originated the said acids, destroy these substances in a very short time.
A very promising Patented process for the removal of lime of Nesbitt
(D R P No. 39265) has not succeeded in practice.
According to the researches of Eitner ("The Tanner" XIIIth year of publication
No. 319 page 281) the removal of lime by means of carbonic acid is illusory.
Likewise the many other processes constantly proposed do not retain a lasting
position in practice.
All the dangers and defects attending the methods hitherto proposed for the removal
of lime from skins, kips and hides disappear by the use of creosotic acid. Its small
solubility in water (the same fluctuates amongst its isomers obtainable from cresol
extracted from coal tar between 1: 1200 and 1:3000) permits to effect a dangerless and
get thorough removal of lime from the skins, kips and hides treated thereby since
any large excess of creosotic acid possibly added to the lime removing liquid can be
used without any injury resulting therefrom.

page_text: While thus added in excess, it remains visible to the tanner and hence forms the
best outward and practical indicative sign for acids still existing in excess.
It only
disappears from sight in the mass as it is becoming neutralized by the lime of the
skins, kips, or hides. By the addition of a volume of muriatic acid equivalent to its
own, the excess of creosotic acid according to the above ratio of solubility is
separated and can be again employed in a similar vessel, or it can be worked in
practice without running any risk with an excess of muriatic acid by precipitating
the same with muriatic acid, filtering off and drying, thus winning the substance
back again in the most simple manner or it can be used when freshly precipitated.
Furthermore, the lime removing process is thereby rendered nearly as cheap as by
using muriatic acid alone as only the volume of the latter acid requisite for
precipitation need be taken into consideration while the creosotic acid remaining in
solution after precipitation for the purpose of winning an excess thereof back again
does not lose in weight owing to the infallibility and simplicity of the process.
Morcover the decomposition of the skins, kips and hides is owing to the high
antiseptic properties of creosotic acid entirely avoided and these go even further as a
decomposition or putrid process already set up in the said skins, kips and hides owing
to their being laid down for too long a time is immediately arrested by a diluted
solution of creosotic acid.
The skins, kips or hides freed from their lime are swollen or puffed in a fresh
solution of creosotic acid a most important operation in the preparation of leather for
H. GARDNER,
166, Fleet Street, London,
Agent for the said J. Hauff.
Dated this 16th day of October 1888.
H. GARDNER,
166, Fleet Street, London,
Agent for the said J. Hauff.