Improvements in the Treatment of Nitrocellulose,
Year: 1898

page_text: Date of Application, 24th Aug., 1898
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Nitrocellulose,
We, ALFRED LUCK, of Brentcote, Dartford, Kent, Chemist, and CHARLES
FREDERICK CROss, of 4, New Court, London, W.C., Chemist, do hereby declare tho
nature of this invention to be as follows:-
In the Specification No. 5286 of 1898, is described a method of treating nitro-
celluloses by solutions which have the effect of disintegrating the fibrous nitrates
producing more or less structureless powders or masses.
Thus
The solutions in question are the solvents of the higher cellulose nitrates diluted
with an inert liquid so as to limit or restrain their normal solvent action.
while acetone itself completely gelatinises and dissolves cellulose nitrate of
a wide range of composition the addition of 10 % of its volume of water converts
it into a liquid having an action of entirely different character. This difference
of action is especially marked in the case where the nitrates are treated in the
form of soft grains. Small masses of nitrates in this form may be treated with
the dilute acetone in excess, being entirely converted under its action into com-
pact more or less structureless grains, without any tendency of these grains to
cohere. The final hardening of the grains results from the removing of the
acetone and in their finished state they have considerable hardness and offer a
satisfactory resistance to crushing.
The treatment described is also applicable to composite grains. Thus we may
first prepare a soft fibrous grain composed of a cellulose nitrate and a restrain-
ing substance such for instance as carbon powder added to slow its combustion.
These grains may then receive a coating of a higher nitrate, also in the fibrous
form.
The composite grain is then put through the hardening treatment that is to say
the action of dilute acetone in excess and after the action is complete the acetone
is removed by farther diluting and drawing off from the granules.
Dated this 24th day of August 1898.
ABEL & IMRAY,
Agents for the Applicants.
Improvements in the Treatment of Nitrocellulose.
We, ALFRED LUCK, of Brentcote, Dartford, Kent, Chemist, and CHARLES
FREDERICK CROSS, of 4, New Court, London, W.C., Chemist, do hereby declare the
[Price 8d.1

page_text: 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 Specification No. 5286 of 1898, is described a method of treating nitro-
celluloses by solutions which have the effect of disintegrating the fibrous nitrates
producing more or less structureless powders or masses.
The solutions in question are the solvents of the higher cellulose nitrates
diluted with an inert liquid so as to limit, or restrain, or stop their normal
solvent action. Thus while acetone itself completely gelatinises and dissolves
cellulose nitrate of a wide range of composition the addition of 10% of its volume
of water converts it into a liquid having an action of entirely different character.
This difference of action is especially marked in the case where the nitrates are
treated in the form of soft grains. Small masses of nitrates in this form may
be treated with the dilute acetone in excess, being entirely converted under its
action into compact more or less structureless grains, without any tendency of
these grains to cohere. The final hardening of the grains results from the
removing of the acetone and in their finished state they have considerable hard-
ness and offer a satisfactory resistance to crushing.
The treatment described is also applicable to composite grains. Thus we may
first prepare a soft fibrous grain composed of a cellulose nitrate and a restrain-
ing substance, such for instance as carbon powder added to slow its combustion.
These grains may then receive a coating of a higher nitrate, also in the fibrous
form.
'
The composite grain is then put through the hardening treatment that is to say
the action of dilute acetone in excess and after the action is complete the acetone
is removed by farther diluting and drawing off from the granules.
The following is an example of this hardening process applied to a cellulose
nitrate containing about 13% nitrogen (ordinary guncotton). It is first formed
into soft grains in the usual well known manner by the action of a revolving
drum or a machine similar to that used for the coating of pills.
The formation of the grains may be facilitated by mixing starch paste with the
nitrocellulose and passing the mass through a sieve having meshes suited to
the size of the grains desired. The grains may be treated while moist, but they
are preferably dried before treatment. The liquid for the treatment is prepared
of more or less strength according to the degree of hardness or density required,
in quantity about 5 litres for each kilo. of the grains. The grains are run into
the liquid which is gently agitated, and if it is required to increase the final
hardening effect, the liquid containing the grains may be heated or boiled. After
soaking the grains in the liquid for about 10 minutes, the action is stopped by
the addition of water in excess, whereupon the grains quickly lose their soft
gelatinous condition and become uniformly hardened. Instead of adding water
to reduce the strength of the liquid, the acetone may be distilled off."
strength of the liquid may be varied between considerable limits. For instance,
soft grains formed from ordinary guncotton may be thoroughly hardened by
treatment with a mixture of 90 parts by volume of acetone to 10 parts of water,
giving finished grains which occupy only about half the bulk, of the same soft
grains treated with 60 parts of acetone to 40 of water.
The
After hardening, the grains are washed and heated to free them as much as
possible from the solvent.
Instead of forming soft grains from cellulose nitrate alone, they may be
formed from cellulose nitrate mixed with ingredients, such as graphite, or lamp-
black or un-nitrated cellulose. The addition of such substances renders the
finished grains more restrained in combustion, it at the same time renders the
grains more difficult to ignite in shot guns. This difficulty may be overcome
and grains may be produced sufficiently restrained in combustion to prevent
dangerous pressures in firearms and at the same time capable of quick ignition
by forming what may be termed "composite grains" in the following manner:-
The soft grains composed of nitro-cellulose (preferably of highest nitration)

page_text: mixed with restraining substance, are coated with nitro-cellulose alone or mixed
with other ingredients so that this outside coating is less restrained than the
core. For instance, soft grains consisting of 70 parts of nitrated cellulose, con-
taining 13.3% nitrogen mixed with 10 parts of graphite have added to them
(preferably while they are in the graining machine) about 20 parts of the
nitrated cellulose dry and the motion is continued until the whole of the added
nitro-cellulose is taken up.
As another example, restrained grains consisting of 70 parts of nitrated cellu-
lose contining 12% nitrogen may be coated with 30 parts of nitrated cellulose
containing 13.3% nitrogen.
The composite grains may be hardened as described.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what
we claim is;-
1. The herein described process for hardening grains consisting of nitro-cellulose
alone or compounded with restraining or other substancos, by subjecting the
soft grains to the action of a diluted solvent, washing and drying.
2. Simple or composite grains of nitro-cellulose hardened as above set forth.
1
1
1
1000
ABEL & IMRAY,
Agents for the Applicants.