IM- PROVEMENTS IN THE TREATMENT OF OLD OR WASTE LEATHER, HIDES, AND SKINS, OR THE SCRAPS, CUTTINGS, AND RESIDUES THEREOF, IN ORDER TO PRODUCE THEREFROM A FABRIC RESEMBLING LEATHER, AND IN RECOVERING TASTY OF TANNED LEATHER."
Year: 1878

page_text: LETTERS PATENT to Thomas Henry Cobley, of Dunstable, in the County of
Bedford, Chemist, and James Storer, of Glasgow, in the County of Lanark,
North Britain, Colour and Varnish Manufacturer, for the Invention of "IM-
PROVEMENTS IN THE TREATMENT OF OLD OR WASTE LEATHER, HIDES, AND
SKINS, OR THE SCRAPS, CUTTINGS, AND RESIDUES THEREOF, IN ORDER TO
PRODUCE THEREFROM A FABRIC RESEMBLING LEATHER, AND IN RECOVERING
TASTY OF TANNED LEATHER."
PROVISIONAL SPECIFICATION left by the said Thomas Henry Cobley and
James Storer at the Office of the Commissioners of Patents on the 12th April
1878.
THOMAS HENRY COBLEY, of Dunstable, in the County of Bedford, Chemist, and
JAMES STORER, of Glasgow, in the County of Lanark, North Britain, Colour and
Varnish Manufacturer. "IMPROVEMENTS IN THE TREATMENT OF OLD OR WASTE
LEATHER, HIDES, AND SKINS, OR THE SCRAPS, CUTTINGS, AND RESIDUES THEREOF, IN
ORDER TO PRODUCE THEREFROM A FABRIC RESEMBLING LEATHER, AND IN RE-
COVERING THE TANNIN OF TANNED LEATHER."
The nature of our said Invention consists in this, that, by certain improved pro-
cesses herein-after described, we utilize old or waste leather, hides, or skins,
or the scraps, cuttings, residues, and fragments thereof by producing therefrom an
artificial fabric resembling leather, and capable of being used for many purposes
instead of leather; and that in the case of tanned leather we recover the tannin
contained therein.
And the means by which the said Invention is carried into effect are as follows,
videlicet:—The first step of our process, when we deal with hides or skins that

page_text: have not been tanned, or with tanned leather which we do not require or desire to
untan, is by moistening and then slicing, chipping, or mincing, and, finally, rasping
or tearing by means of suitable instruments or machinery to reduce the material
to the condition of fibrous pulp.
For the production of the leather-like fabric above mentioned from old or waste
leather containing tannin it is not necessary that we remove or destroy the tannin ;
but we can do so if it is desired, either by treating it before or after pulping with
caustic alkalis or carbonates of the alkalis, or with tartaric or acetic acid in solution,
according to the known method, or by treating it with wood spirit, methylated
spirit, or fusel oil or equivalent forms of alcohol, or mixtures of alcohol and acetic
or pyroligneous acid, as herein-after described.
Our object is not to gelatinize more than is needed, nor otherwise to destroy the
fibre of the hide.
Strong solutions of caustic alkalis or alkaline carbonates and mineral acids, and even
strong solutions of organic acids, especially with the acid of heat, not only remove the
tannin by converting it into gallic acid, which in alkaline solutions rapidly absorbs
oxygen, and passes into ellagic acid and ulterior products of a humic character,
which do not retain the power of fixing themselves on the animal fibre as tannin
does, but tend to alter the character of the fibre itself in a way which prevents
the proper formation of the fabric we wish to produce.
If used to remove the tannin the alkalis, alkaline carbonates, and mineral acids,
and also the organic acids above mentioned, must be used very cautiously, and in
weak solutions, or with great dilution and in the cold, so as not to effect too
destructively the fibre of the hide.
If the object is simply to destroy the tannin without wishing to recover it, per-
manganate of potash may be applied to the pulp, which will oxidise the tannin
Linto products incapable of remaining combined with the fibre of the hide, and will
.do so without injuriously affecting the fibre.
We prefer, however, to use for removing the tannin such alcohols as can be pro-
cured cheaply, and in particular wood naphtha, otherwise known as wood spirit,
pyroligneous spirit or ether, or crude methylic alcohol, which also generally contains
a certain admixture of acetic or pyroligneous acid; or, again, any cheap form of
vinic or ethylic alcohol, such as methylated spirit, or any of the cheap varieties of
"fusel" oil.
We digest the leather chips or leather pulp with these alcoholic re-agents in the
cold for several days, or until such time as the tannin is well dissolved out into
the menstruum, taking care, if we wish to recover the tannin for use again, to
hinder the access of atmospheric air, as solutions of tannin are liable to pass under
the influence of oxygen into gallic acid, and other compounds useless for tanning
purposes.
The liquor containing the tannin thus dissolved out into it is separated from the
chips or pulp by pressure, and this liquor may then be distilled whon the wood
naphtha or alcohol passes over into the refrigerator in a purified condition, carrying
with it any acetic acid, and leaving behind the tannic acid which may be preserved
for use by well-known methods and the distillate consisting of alcohol, and, as the
case may be; also, acetic acid may be either further treated to separate the alcohol
and acetic acid, or may be used over again without any further treating.
Tannin or tannic acid, when extracted by an acid menstruum or in acid solution,
passes into gallic acid; but the latter does not, as in alkaline solutions, pass into
ellagic acid or further products of decomposition. The gallic acid of dilute acid or
alcoholic solutions may be re-converted into tannic acid by boiling these solutions
with arsenic acid..
The fibrous pulp, whether previously subjected to the untanning process or not,
is treated in the cold and moist condition with the sulphurous acid, either in the
form of dry gas passed into and through it, which is preferable, or in the form of
aqueous sulphurous acid.

page_text: A convenient method is to keep the moist pulp well stamped, or beaten or ground,
while the sulphurous acid is being gradually added to or passed through it.
If the pulp be pressed into sheets at once without this treatment with sul-
phurous acid or some equivalent treatment, as after mentioned, we find that the
product is frush, or short, brittle, and inflexible; and the object of this treatment
with sulphurous acid, before pressing into sheets, is to produce greater agglutination
or adhesiveness of the fibres among themselves when afterwards pressed, and to
give greater pliancy to the fabric to be obtained by pressure. The pulp is then
subjected to moderate pressure in the first instance to express superfluous moisture,
which may be done in wire moulds, or in a centrifugal machine, or by other well-
known means.
It is then pressed into sheets with hot plates, or rolled with hot
rollers; or the same result may be effected by hydraulic or other couvenient pressure.
Instead of using sulphurous acid, as herein-before described, we find that we can
use other re-agents, such as sulphuretted hydrogen, the acid sulphites of the alkalis
and earths, sulphide of barium, carbolic acid, tartaric acid, corrosive sublimate, and
urine.
The sheets obtained by the rolling or pressing are then allowed to dry slowly;
they are then tanned or tawed if necessary or desirable; but, whether tanned or
tawed or not, they are again heavily rolled or pressed, and finished.
In case of tanning we use the bark of the willow, on account of the salicylic
acid contained in it having a more favourable effect upon the material, where the
gelatine is in the peculiar modification found in old leather.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Henry Cobley and James Storer in the Great Seal Patent
Office on the 11th October 1878.
THOMAS HENRY COBLEY, of Dunstable, in the County of Bedford, Chemist, and
JAMES STORER, of Glasgow, in the County of Lanark, North Britain, Colour and
Varnish Manufacturer. "IMPROVEMENTS IN THE TREATMENT OF OLD OR WASTE
LEATHER, HIDES, AND SKINS, OR THE SCRAPS, CUTTINGS, AND RESIDUES THEREOF,
IN ORDER TO PRODUCE THEREFROM A FABRIC RESEMBLING LEATHER, AND IN RE-
COVERING THE TANNIN OF TANNED LEATHER."
The nature of our said Invention consists in this, that, by certain improved pro-
cesses herein-after described, we utilize old or waste leather, hides, or skins, or the
scraps, cuttings, residues, and fragments thereof by producing therefrom an artificial
fabric resembling leather, and capable of being used for many purposes instead of
leather; and that in the case of tanned leather we recover the tannin contained
therein.
And the means by which the said Invention is carried into effect are as follows,
videlicet:-The first step of our process, when we deal with hides or skins that
have not been tanned, or with tanned leather which we do not require or desire
to untan is by moistening, and then slicing, chipping, or mincing; and, finally
rasping or tearing by means of suitable instruments or machinery to reduce the
material to the condition of fibrous pulp.
For the production of the leather-like fibre above mentioned from old or waste
leather containing tannin it is not necessary that we remove or destroy the tannin;
but we can do so if it is desired, either by treating it before or after pulping, with
caustic alkalis or carbonates of the alkalis or with tartaric or acetic acid in solution,
according to the known method, or by treating it with wood spirit, methylated
spirit, or fuscl oil, or equivalent forms of alcohol or mixtures of alcohol and acetic
or pyroligneous acid, as herein-after described.
Our object is not to gelatinize more than is needed, nor otherwise to destroy the
fibre of the hide.
J
Strong solutions of caustic alkalis or alkaline carbonates and mineral acids, and
even strong solutions of organic acids, especially with the aid of heat, not only
remove the tannin by converting it into gallic acid, which in alkaline solutions
rapidly absorbs oxygen, and passes into ellagic acid and ulterior products of a
humic character, which do not retain the power of fixing themselves on the animal
fibre as tannin does, but tend to alter the character of the fibre itself in a way which
prevents the proper formation of the fabric we wish to produce.
If used to remove the tannin the alkalis, alkaline carbonates, and mineral acids,
and also the organic acids above mentioned, must be used very cautiously, and in
weak solutions, or with great dilution and in the cold, so as not to affect too
destructively the fibre of the hide.
If the object is simply to destroy the tannin without wishing to recover it, per-
manganate of potash may be applied to the pulp, which will oxidise the tannin
into products incapable of remaining combined with the fibre of the hide, and will
do so without injuriously affecting the fibre.
We prefer, however, to use for removing the tannin such alcohols as can be pro-
cured cheaply, and in particular wood naphtha, otherwise known as wood spirit,
pyroligueous spirit or either, or crude methylic alcohol, which also generally contains
a certain admixture of acetic or pyroligneous acid; or, again, any cheap form of
vinic or ethylic alcohol, such as methylated spirit, or any of the cheap varieties of
fusel oil.
Wo digest the leather chips or leather pulp with these alcoholic re-agents in the
cold for several days, or until such time as the tannin is well dissolved out into
the menstruum, taking care, if we wish to recover the tannin for uso again, to

page_text: hinder the access of atmospheric air, as solutions of tannin are liable to pass under
the influence of oxygen into gallic acid, and other compounds uscless for tanning
purposes.
The liquor containing the tannin thus dissolved out into it is separated from the
chips or pulp by pressure, and this liquor may then be distilled when the wood
naphtha or alcohol passes over into the refrigerator in a purified condition, carrying
with it any acetic acid, and leaving behind the tannic acid which may be preserved
for use by well-known methods, and the distillate consisting of alcohol, and, as the
case may be, also acetic acid may be either further treated to separate the alcohol
and acetic acid, or may be used over again without further treating.
The alkaline liquor containing the tannin may, instead of being distilled or
otherwise treated to separate the tannin in pure form, be utilized by the addition
of ferric sulphate, which will precipitate the tannin as tannate of iron; and this
last-mentioned substance may be used for the manufacture of a blacking for
coating leather and similar substances, including the leathor-like fabric abovo
mentioned.
Tannin or tannic acid, when extracted by an acid menstruum or in acid solution,
passes into gallic acid; but when the latter does not, as in alkaline solutions, pass
into ellagic acid, or further products of decomposition, the gallic acid of dilute acid
or alcoholic solutions may be re-converted into tannic acid by boiling these solutions
with with arsenic acid.
The fibrous pulp, whether previously subjected to the untanning process or not,
is treated in the cold and in moist condition with sulphurous acid, either in the
form of dry gas passed into and through it, which is preferable, or in the form of
aqueous sulphuric acid...
A convenient method is to keep the moist pulp well stamped, or beaton or ground,
while the sulphurous acid is being gradually added to or passed through it.
If the pulp be pressed into sheets at once without this treatment with sulphurous
acid, or some equivalent treatment, as after mentioned, we find that the product is
frush or short, brittle, and inflexible; and the object of this treatment with sul-
phurous acid, before pressing into sheets, is to produce greater agglutination or
adhesiveness of the fibres among themselves when afterwards pressed, and to give
greater pliancy to the fabric to be obtained by pressure. The pulp is then sub-
jected to moderate pressure, in the first instance, to express superfluous moisture,
which may be done in wire moulds or in a centrifugal machine, or by other
well-known means. The pulp thus prepared is most conveniently formed into
sheets by the same means as those employed in making hand-made paper with
vats, moulds, and presses; or it may be pressed into blocks or forms for the heels
of boots and shoes. After pressing, and previous to rolling, it should be sized with
pinite of alumina or boracic solution of casein, glycerate of lead. To render them
more impervious to moisture the sheets thus obtained may be coated with gutta
percha by immersing them in a solution of gutta percha, and then rolling them.
It is then pressed into sheets with hot plates, or rolled with hot rollers, or the
same result may be effected by hydraulic or other convenient pressure.
Instead of using sulphurous acid, as berein-before described, we find that we can
use other re-agents, such as sulphuretted hydrogen, the acid sulphites of the alkalis
and earths, sulphide of barium, carbolic acid, tartaric acid, corrosive sublimate, and
urine.
The sheets obtained by the rolling or pressing are then allowed to dry slowly;
they are then tanned or tawed if necessary or desirable; but, whether tanned or
tawed or not, they are again heavily rolled or pressed, and finished.
In case of tanning we use the bark of the willow on account of the salicylic acid
contained in it having a more favourable effect upon the material, where the
gelatine is in the peculiar modification found in old leather.
Having now described and particularly ascertained the nature of our said Inven-
tion, and the system, mode, or manner in or under which the same is or may be
used or practically carried into effect, we would observe in conclusion that what

page_text: we consider to be novel and original, and therefore claim as the Invention secured
to us by the herein-before in part recited Letters Patent is,-
First. The improvements in the treatment of old scrap or waste leather, hides,
and skins herein-before described.
Second. Untanning leather waste, and recovering the tannin by the means herein
set forth without impairing the fibre or removing the gelatine, as herein-before
described.
Third. The production of colloidal tannate of iron for blacking and polish manu-
facture from the alkaline tannates produced in the preparation of the waste leather,
as heroin-before described.
Fourth. The herein-before described means of converting the untanned leather
waste into "leatherine" or fabric resembling leather.
Fifth. The use of salicylic acid liquor (willow bark extract) for retanning the
"leatherine," as herein-before described.
Sixth. The use of boracic solution of casein and glycerate of lead for sizing, as
herein-before described.
"
Seventh. Coating the "leatherine' thus prepared with a coating of gutta
percha, as herein-before described.
In witness whereof, I, the said Thomas Henry Cobley, on behalf of James
Storer and myself, have hereunto set my hand and seal, this Ninth day of
October, One thousand eight hundred and seventy-eight.
T. H. COBLEY. (LS.)