Improvements in the Manufacture of Enamelled Leather.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Enamelled Leather.
We, WALTER FRANCIS REID, of Fieldside, Addlestone, in the County of Surrey,
Civil Engineer, and EDWARD JOHN VAVASOUR EARLE, of 139, Queen Victoria
Street, in the City of London, Merchant, do hereby declare the nature of this
invention to be as follows:-
In the manufacture of ordinary enamelled leather, the enamel, which is
largely composed of boiled linseed oil, has a tendency to harden and crack even
before it is made up into boots or similar articles. To prepare an enamelled
leather free from this defect we employ a solution of nitro-cellulose and nitro-
linolein or nitro-ricinolein in any of the usual solvents of nitro-cellulose. The
leather, having been prepared for enamelling in the ordinary way, is first treated
with a weak solution applied either to the grain or flesh side. After the surface
of the leather has been prepared in this way more concentrated solutions are
applied and finally the proportion of solvent may be still further reduced and a
paste being used of such consistency that when a portion of it is placed upon a
level surface it will flow and show a glossy surface. Any desired colouring
matter may be added to the solutions or paste, preferably in the form of alcohol-
soluble colours.
If preferred, the solution may be converted into a film by pouring it upon
a glass or other polished surface, the film thus produced being united to the
leather by moistening with a solvent and then applying pressure.
After the leather has been coated it may be heated to about 100° Fahrenheit
for 24 hours and is then ready for use.
Improvements in the Manufacture of Enamelled Leather.
We, WALTER FRANCIS REID, of Fieldside, Addlestone, in the County of Surrey,
vil Engineer, and EDWARD JOHN VAVASOUR EARLE, of 139, Queen Victoria
[Price 8d.]

page_text: Street, in the City of London, Merchant, 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:-
In the manufacture of ordinary enamelled leather the enamel which is largely
composed of boiled linseed oil has a tendency to harden and crack even before
it is made up into boots or similar articles.
To prepare an enamelled leather free from this defect we employ an enamel
composed of nitro-cellulose and nitro-linolein or nitro-ricinolein. Such com-
pounds form the subject of our Patent of the 19th day of October 1895, No. 21995.
A very suitable mixture is that of 11 parts by weight of nitrated castor oil
to 5 parts of soluble nitro-cellulose..
..
The leather is first "buffed in the ordinary way to prepare it for enamelling
and it is then treated with a weak solution of the mixture in any of the usual
solvents of nitro-cellulose. Preferably we employ 95 parts, of acetone to 5 parts
of the mixture. This solution is applied either to the grain or the flesh side of
the leather by means of a brush or otherwise. One or more coats of a stronger
solution containing say 10 parts of the mixture to 90 parts of acetone are then
applied, or in place of the second and subsequent liquid coats a paste formed
of say 15 parts of the mixture to 85 parts of acetone may be applied by mechanical
spreaders such as are used for india rubber. The object of the preliminary
weak solution is to carry the mixture of nitro-compounds into the leather so as
to get a firm hold on it; if a strong solution or paste were used in the first instance
it would be liable to merely form a readily detachable skin on the surface.
A very beautiful polished surface may be obtained by employing a film
produced by pouring a fairly fluid solution containing say 6 or 7 parts of the
mixture to 94 or 93 parts of acetone upon a sheet of glass or the like and evapora-
ting the solvent. The leather is dipped in acetone or the like, is passed between
rollers to squeeze out the superfluous solvent and is then pressed by means of a
roller or otherwise upon the film whilst it is still on the glass. The solvent is
evaporated from the uncovered surface of the leather, and the glass with the film
and leather on it is put into an atmosphere saturated with moisture and the
leather with the film adhering to it can then be readily stripped off the glass.
The effect of this method is similar to that first described, for the solvent in the
leather attacks the surface of the film making a weak solution which as the sol-
vent evaporates from the uncovered surface is drawn up into the leather by
capillary attraction thus firmly uniting the film to the leather.
After the leather has been coated it should be kept at a temperature of
about 100° Fahrenheit to completely evaporate the solvent.
Colouring matters may be mixed with the solutions; if an
desired the colours should be soluble in the solvents employed, insoluble colours
even tint be
give a mottled effect. Coloured designs may also be made on the glass or
other sheet before pouring on the solution or the sheet may be engraved with
a pattern.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. Leather enamelled with a mixture of nitro-cellulose and nitro-linolein or
nitro-ricinolein.
2. The process of enamelling leather consisting in impregnating its surface
with a weak solution of a mixture of nitro-cellulose and nitro-linolein or
nitro-ricinolein, applying more of the mixture to the surface so prepared and
then evaporating the solvent.
3. The process of enamelling leather consisting in impregnating its surface
with a weak solution of nitro-cellulose and nitro-linolein or nitro-ricinolein, then

page_text: coating the surface with a stronger solution or solutions or paste of the same
and evaporating the solvent.
4. The process of enamelling leather consisting in impregnating its surface
with a solvent applying a film of nitro-cellulose and nitro-linolein or nitro-
ricinolein and evaporating the solvent.
5. Enamelled leather and the processes for making the same substantially
as described.
Dated this 30th day of July 1898
WALTER FRANCIS REID.
EDWARD JOHN VAVASOUR EARLE.