Improvements in Treating Hides and Skins.
Year: 1898

page_text: Date of Application, 28th Dec., 1898-Accepted, 11th Feb., 1899
COMPLETE SPECIFICATION.
Improvements in Treating Hides and Skins.
I, JOHN KIEL TULLIS, of 1, Ford Road, Kelvinside, in the County of the City
of Glasgow, North Britain, Tanner and Currier, 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:-
My invention relates to improvements in treating and tanning hides or skins,
and the objects of the invention are to provide
1. A one bath process, which is simple, rapid and cheap, to produce a soft, tough,
and pliable leather suitable for a variety of purposes, and
2. A combination tannage whereby the present known tannic acid tanning
mediums, such as oak bark hemlock bark, valonea, gambir, divi-divi, canaigre root,
chesnut, etc etc., also mineral salts tannages, such as the chromium and iron com-
pounds, are used in conjunction with the new process or invention herein claimed,
in order to greatly accelerate the actual time required to tan or make leather, with-
out in any way impairing the quality of the leather so produced.
My invention consists essentially in subjecting the hides or skins to be tanned
to the action of acetic aldehyde (C, H, O), either as an aqueous solution or as a
natural nascent gas in such a manner or proportion and for such a period of time
that the hide or skin under treatment may require to convert it into leather. Such
treatment by acetic aldehyde (C, H, O) renders the hide or skin very absorbtive
and it imbibes the tanning medium with great avidity, and very strong tanning
liquors may be employed without "drawing" the grain, or otherwise injuring the
hide or skin. Acetic aldehyde (CHO) may be prepared from methylated spirit
or from other suitable source.
In the practical working of my process or invention I proceed as follows:--The
hides or skins are prepared by the usual or common modes of washing, unhairing,
fleshing, bating, drenching, etc
(a) The hides or skins are suspended in an aqueous solution of acetic
aldehyde (C, H, 0), varying in strength of from one fifth per mille to five per centum
of acetic aldehyde according to the kind, thickness, and character of the hides or
skins to be treated, and allowed to remain in this solution from 12 to 24 hours,
during which time they are frequently "handled" or moved by mechanical means.
In order to test if the acetic aldehyde (CHO) has sufficiently acted on the ludes
or skins, a small piece should be cut off and sharply bent flesh inwards and then
grain inwards, and should'the bent parts show up white or rose white and present
a dry appearance, the action of the acetic aldehyde has been sufficient and complete
The hides or skins are now removed to the tanning pits or to mechanically driven
druma, and are rapidly tanned therein in tanning liquors or extracts varying
from 30 to 16° of Twaddells hydrometer. Heavy hides may be tanned in from 10
to 15 days by any of the well-known tannic acid processes in still liquors, and in
36 to 48 hours when suitable mechanical appliances are used. When chromium
or iron salts are used as a tanning medium 3 to 4 days will suffice for complete
tannage in still liquors, and 24 to 36 hours when suitable mechanical appliances
n
077

page_text: are used. The hides or skins are then curried and finished by the usual process
Skins or hides to be finished without removing hair, fur, or wool, may also be
treated with acetic aldehyde either in the form of a gas or as an aqueous solution.
(b) The hides on skins are suspended in a chamber capable of being hermetically
alosed and connected with any suitable form of apparatus for generating acetic
aldehyde gas. When the hides or skins have been suspended in this chamber and
the chamber closed, acetic aldehyde gas is then introduced in such quantity or
volume as is necessary for the treatment of the hides or skins, or until such hides
or skins shall be thoroughly and intimately permeated by the acetic aldehyde gas
or mixed gas and aqueous vapour and successfully stand the application of the test
described under paragraph a
I find that the volume of acetic aldehyde gas required to treat or tan hides or
skins varies from one fifth per mille to 5% of the capacity of the chamber filled
with an at the ordinary temperature according to the thickness, quality, and
character of the skins or hides The atmosphere of the acetic aldehyde gas
chamber should be agitated from time to time by suitable mechanical means 90
as to produce a uniform density of vapour throughout the chamber and I find that
the period of time required for the acetic aldehyde gas to act sufficiently upon
the hides and skins as per test in paragraph, is from 2 to 12 hours according to
the thickness, character, and quality of the skins or hides used
The hides or skins are now removed to the tanning pits on to mechanically
diven drums, and are rapidly tanned therein in tanning liquors or extracts vary-
ing from 30 to 16° of Twaddells hydrometer Heavy hides may be tanned in
from 10 to 15 days by any of the well known tannic acid processes in still liquors,
and in 36 to 48 hours when suitable mechanical appliances are used
When
chromium or non salts are used as a tanning medium to 4 days will suffice for
complete tannage in still liquors, and 24 to 36 hours when suitable mechanical
appliances are used. The hides oi skins are then cued and finished by the usual
process.
(c) The hides or skins may also be first subjected to weak tanning liquors for
48 hours and then follow the processes as described under paragraphs a and b
Having now particularly described and ascertained the nature of my said
invention and in what manner the same 18 to be performed, I declare that what
I claim is..
1. Acetic aldehyde in the form of a gas or as an aqueous solution as a new
article of manufacture for use in the tanyard.
2. Tanning or curing hides or skins as herein described, that is to say subjecting
the hide or skin to be tanned or cured to the action of acetic aldehyde (CHO)
as herein act forth
3 The process herein described of tanning or curing, that is to say, subjecting
the hide or skin to be tanned or cured to the action of acetic aldehyde (CHO)
gas co-mingled with aqueous vapour, substantially as herein set forth
4 The process herein described of teating hides and skins with acetic aldehyde
in combination with treating of them with tanning or like substances, substantially
as herein set forth.
יו
L
1000
BOTTOMLEY & LIDDLE,
154, St Vincent Street, Glasgow, Applicant's Patent Agents.