Improvements in Treating Hides and Skins
Year: 1897

page_text: 66
PROVISIONAL SPECIFICATION.
'Improvements in Treating Hides and Skins."
We, SAMUEL MILLAR, 2 Broompark Terrace, Dennistoun, in the County of
Glasgow, North Britain, Tanner, and CHARLES EDWARD MILLER, 6, Gibson Street,
Hillhead, in the same County, Technical Chemist, do hereby declare the nature
of this Invention to be as follows, that is to say:
This Invention has for its object the treating of hides and skins in an improved,
expeditious, and economical manner, and so as to obtain results like those
ordinarily obtained by tanning.
The Invention consists in treating the hides and skins after removal of hair and
flesh, with formalin or a solution of formic aldehyde. The hides and skins are
steeped in the solution during a few hours, and the formic aldehyde acts on the
gelatinous constituents in a manner to render them insoluble and is otherwise
advantageous. In somes cases the hides and skins may be superficially tanned
or treated with bark or the like in the ordinary way before being treated with
the formalin. The hides and skins may be finished by any suitable known process
or combination of processes.
Dated this fifth day of February 1897
EDMUND HUNT.
Applicants' Agent.
66 Improvements in Treating Hides and Skins."
We, SAMUEL MILLAR, 2 Broompark Terrace, Dennistoun, in the County of
Glasgow, North Britain, Tanner, and CHARLES. EDWARD MILLER, G, Gibson Street,
Hillhead, in the same County, Technical Chemist, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement:-that is
to say:
This Invention has for its object the treating of hides and skins in an improved,
expeditious, and economical manner, and so as to obtain results like or superior
to those obtained by ordinary tanning processes.
An essental constituent of the Invention is the use of formalin or a solution
of formic aldehyde; and we find it can be used to most advantage when combined
with ordinary tanning processes. We may treat the hides and skins after
removal of hair and flesh with the formalin and afterwards with tannin materials;
or we may use formalin and tanning solutions together; or we may first subject
Price 8d 1

page_text: the hides and skins to tanning processes and subsequently treat them with
formalin.
The details of the combined processes to be adopted in carrying out the Inven-
tion may be considerably varied in practice according to the requirements in each
case and other circumstance; but very good results are obtainable by operating
in the following manner.
The hides or skins are unhaired in the usual way, and put into weak tanning
liquors for three or four days until the lime in them is neutralised. They are
then suspended in a weak solution of formalin (of a strength of about 40 per cent.
formic aldehyde) three to four gallons of the formalin being used for 100 hides,
weighing on an average 80 pounds each, in from 1400 to 1800 gallons of water.
The first pack of 100 hides will require five to six gallons of formalin, but for
any subsequent pack three to four gallons will suffice, it being unnecessary to
renew the water in the vat for each fresh pack. The formalin renders the gelatine
in the hides or skins insoluble and at the same time greatly increases the absorp
tive power, so that the hides or skins take the tannin very rapidly.
The hides or skins may remain in the formalin solution for from 24 to 48
hours. To test if the formalin has acted sufficiently a small piece may be cut
off and boiled in water for two minutes. If on cooling the hide or skin remains
tough, pliable, and not easy to tear, the action is complete and the hides, or skins
may be taken from the formalin vat, and be subjected to any of the well known
tanning processes, such processes, however, occupying much less time than has
hitherto been required.
The hides or skins can at once be put into a strong tanning liquor, say of a
strength of 14 degrees Twaddell, and the liquor may be maintained at that
strength or made stronger, without in any way drawing the grain, destroying,
or weakening the fibre, the leather produced being tough, firm, and mellow. The
time required for tanning an 80 pound hide is from 11 to 14 days. If mechanical
appliances are used for moving the hides or skins or stirring, the liquors the
tanning operation may be completed in a few hours.
Very light-weighing leather for belting, harness, or dressing purposes can be
produced by taking the hides from the tan pits before the tannin has penetrated
through the hide; or the hide may be partially tanned by regular process; and
in either case then treated with formalin solution to render insoluble the gelatine
in the centre of the hide which has not been acted on by the tannin.
Skins to be finished without removing hair, fur, or wool, may also be treated
wth formalin solution.
The treatment with formalin solution may also be advantageously combined
with what are known as chrome-tanning processes.
Having now particularly described and ascertained the nature of the said Inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
The treating of hides and skins with formalin in combination with the treating
of them with tanning or like substances substantially as herein before described.
Dated this third day of November, 1897.
EDMUND HUNT.
Applicants' Agent.