Improvements in Explosive Material and in the Manufacture thereof.
Year: 1893

page_text: Date of Application, 11th Jan., 1893-Accepted, 25th Feb., 1893
COMPLETE SPECIFICATION.
Improvements in Explosive Material and in the Manufacture thereof.
I, BENJAMIN JOSEPH BARNARD MILLS of 23 Southampton Buildings in the
County of Middlesex Patent Agent, do hereby declare the nature of this inven-
tion, (a communication to me from Charles Edward Munroe, Chemist, residing at
the Naval Torpedo Station at Newport, State of Rhode Island, one of the United
States of America) and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The object of the invention is to produce a powder or material for use as a
propellant in fire arms, which shall be capable of giving a high velocity to the
projectile without the production of a dangerous pressure in the barrel of the gun,
and without the production of smoke to any serious extent, and which is incapable
of being exploded with detonation. To accomplish this gun cotton is used, and it
is best, in order to secure a perfect and uniforin product, to first purify the same
by exposure to the action of a solvent such as methyl alcohol which acts upon the
lower cellulose nitrates and other soluble products of nitration but not upon the
higher nitrate to any material extent, and which by percolation through the gun-
cotton-removes the soluble portions.
The solvent which it is preferred to employ is methyl alcohol which preferably
has been previously freed by distillation, saponification, or other known or suitable
process from acetone and such other impurities as have a solvent action on the
bigher cellulose nitrates. There are many ways in which the solvent can be
effectively applied, but it is preferred to make use of a process of exhaustion by
means of a constant circulating extractor in which the solvent is in a warm condition
when it is brought in contact with the gun cotton, and in which a single charge of
the solvent is, by repeated distillation and condensation, repeatedly brought into
contact. with the same charge of gun cotton, or with successive charges, until
exhaustion is complete. By this means, or by other equivalent or suitable methods,
the gun-cotton may be practically freed from the lower nitrates and from all other
impurities of nitration, and the resulting product brought to a highly pure and
uniform condition, it consisting wholly or substantially so of that form of cellulose
nitrate which is known as the insoluble gun-cotton as distinguished from the
soluble form.
A uniform material is thus obtained instead of one containing a variable and
uncertain quantity of the lower nitrates, and therefore having an uncertain value
as an explosive, as has been the case with the gun-cotton heretefore employed for
military purposes. This material is mixed with a liquid nitro-substitution product
such as nitro-benzene, (C.H.NO,), the same being incorporated thoroughly. with
the gun-cotton in a mill or between rolls, so that the gun-cotton is acted upon
throughout by the nitro-benzene and by which preferably, it is shaped into sheets.
The material, which is now of a plastic, coherent and homogeneous character, is
then preferably cut, moulded, rolled or, otherwise. formed into strips, grains, wires
or other forms, the size and form given to the material being varied according to
the use to which it is to be put. This process by which the dry gun-cotton is
converted into a plastic homogeneous, coherent and non-explosive substance which
retains its coherency and plasticity even while it is exposed to the air, and which

page_text: is capable of being indurated or converted into a hard, horny product by the
process hereinafter described I term "colloidizing." Nitro-benzene is believed
to be the most suitable colloidizing agent, but the present invention is not
confined to the use of such material, for I consider the use of any agent by
which the gun-cotton may be converted into a material of sufficient plasticity to
enable the thorough incorporation of the colloidizing agent to be effected and
which retains its plasticity and coherency while exposed to the air and which is
capable of induration as hereinafter described, to be within the scope of the present
invention. I prefer to use from about nine-tenths to about one and eight-tenths
parts of nitro-benzene to one part of gun cotton.
The material may be mixed with suitable oxidizing salts to perfect combustion;
the kind and quantity of such oxidizing salts being varied according to the use to
which the product is to be put, as will be understood.
The material is now indurated by the action of heated liquids or the vapours
thereof. It is preferred to employ water or steam or both. It has been discovered
that nitrated cellulose after being colloidized in the manner described by. me, if
treated by hot liquid or vapour, becomes indurated and is converted into a material
having the consistency of bone, ivory and like substances, and by so treating the
colloidized material a substance is obtained of much density, great toughness, very
close grained texture, great superficial hardness and smoothness, which is insoluble
in water and completely resists disintegration thereby. The material is also
incapable of being exploded by detonation, but burns with such rapidity as to
produce a high velocity of the projectile when used in firearms, but without creating
a dangerous pressure in the barrel, and also without the presence of smoke to any
material extent.
To this new explosive material has been given the name ❝ Indurite."
Any suitable method and apparatus for applying the heated liquid or vapour
may be employed; for instance, the material may be placed in a vessel through
which the liquid is caused to circulate, and through which also the heated steam
or vapour is caused to pass.
The time of exposure to the liquid depends upon the degree of sub division of
the material; for instance, the small grains best adapted to use with small arms
require an exposure of about twelve hours with water at the boiling point to
complete the process. With larger pieces the time required is proportionately
longer.
÷
It is not essential that the plastic colloidized material shall be immediately
exposed to the indurating process, since the plastic material may be conveniently
stored and transported, it being non-explosive, and the indurating step may be
performed subsequently or as the material is required for use.
If instead of employing the first step of purifying the ordinary gun cotton of
commerce, is colloidized and indurated a material is obtained which while it has
not the uniformity which makes it suitable for military uses, is useful for blasting
and other purposes.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that do not
claim as my invention the application per se of heated liquids or vapours to nitro-
cellulose in the manufacture of explosive material, but I claim this step only in the
process involving the previous step of colloidization what I claim is :-
1. The explosive powder or material called "indurite " made by mixing aud
incorporating with gun cotton a colloidizing agent such as nitro-benzene, and then
indurating the colloidized material, as by treatment with heated liquids or vapours,
substantially as hereinbefore described.
"
2. The explosive powder or material called "indurite made by mixing and
incorporating a colloidizing agent such as nitro-benzene with gun-cotton which has
first been purified and freed from the lower or soluble products of nitration by the
action of a solvent such as methyl alcohol, and then indurating the colloidized

page_text: material as by treatment with heated liquids or vapours substantially as herein-
before described.
3. The explosive powder or material called "indurite" made by mixing and
incorporating a colloidizing agent such as nitro-benzene with gun cotton which
has first been purified and freed from the lower or soluble products of nitration
by the action of a solvent such as methyl alcohol, then dividing the plastic
colloidized material into strips, grains or other forms, and then indurating the
colloidized material as by treatment with heated liquids or vapours substantially as
herein before described.
Dated 141 3.
B. J. B. MILLS,
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.