Improvements in the Preparation of Explosive Compounds.
Year: 1889

page_text: Date of Application, 5th June, 1889
Complete Specification Left, 3rd Apr., 1390-Accepted, 3rd May, 1890
PROVISIONAL SPECIFICATION.
[Communicated from abroad by ALFRED NOBEL, of 53, Avenue Malakoff, in the
Republic of France, Engineer.]
Improvements in the Preparation of Explosive Compounds.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 6 Bream's Buildings,
Chancery Lane, in the County of Middlesex, Mechanical Draughtsman, do hereby
declare the nature of this invention to be as follows:-
In the specification of Letters Patent dated 31st January 1888, No. 1471, I
described various modes of making, from nitro-glycerine and soluble nitro-cellulose, a
horny or semi-horny explosive compound.
It has since been found that an explosive compound similar to that described
in the aforesaid patent, can be produced by somewhat varying the process of
manufacture.
Thus, a very simple and easy mode of preparing such an explosive compound,
consists in immersing, in a bath of nitro-glycerine, kept at the lowest practicable
temperature, (say 5 to 8 degrees Centigrade), such quantity of soluble nitro-cellulose
as can be conveniently soaked therein. The spongy mass thus obtained is then
brought under a press, and so much of the nitro-glycerine is squeezed out, as will
leave absorbed in the said nitro-cellulose, say, only its own weight of nitro-
glycerine.
If the nitro-cellulose employed contains water, which it may, without much incon-
venience, up to 30% of its weight, then the nitro-glycerine left should be pro-
portionate only to the quantity contained therein of dry nitro-cellulose. The quantity
of nitro-glycerine which the nitro-cellulose still retains, is ascertained by weighing
the quantity of nitro-glycerine squeezed out, and for which ready outflow should be
provided.
Instead of soaking nitro-cellulose in nitro-glycerine, as aforesaid, and extracting
the surplus liquid by pressure, the two substances may be mixed together in equal
proportions, but it is very difficult thus to obtain a homogeneous distribution of the
liquid explosive throughout the large bulk of nitro-cellulose needed, and therefore the
operation of soaking and extracting as above described, is preferable. The compressed
cake thereby obtained is taken out of the press, and immersed in boiling water, when
the dissolving action of the nitro-glycerine on the nitro-cellulose immediately begins.
The incorporation is thus more rapidly completed than by heating the said cake in a
water bath, but either of the two methods may be used. When the incorporation is
completed, the compound thus obtained is laminated between steam-heated mixing
rollers in the manner described in the aforesaid patent No. 1471, or compressed, when
heated, to say, 80° Centigrade, in a press, but malaxation between steam-heated
rollers permits of obtaining the most perfect product.
In the process herein described, great care should be taken to have the nitro-
cellulose in such state of division that the nitro-glycerine gets easy access to all its
pores, and becomes uniformly distributed therein.
Should nitro-cellulose used in the aforesaid operation be of such nature as to be
partly soluble in nitro-glycerine at the aforesaid temperature, and tend to thicken the
said explosive liquid, in such case it will be necessary to add a small portion of benzol
or analogous liquid, sufficient, however, to prevent the said dissolving action,-it being
necessary to preserve to the nitro-glycerine squeezed out, as aforesaid, its fluidity, so
as to render it suitable for succeeding operations of the same kind. The small
quantity of benzol added readily evaporates, when exposed to the open air, or to a
current of air directed thereon.
The explosive compound may be obtained by immersing nitro-cellulose in nitro-

page_text: glycerine, as aforesaid, but I extract, by pressure, less nitro-glycerine, leaving in the
nitro-cellulose, say, double its own weight of nitro-glycerine. After due heating and
incorporation in manner already described, the explosive substance obtained is too
soft for severance into so-called grains. For the purpose of hardening it, it is rolled
out into very thin sheets, which are then immersed in a bath having the property of
dissolving nitro-glycerine, but not nitro-cellulose. Such a bath is conveniently formed
by diluting methylic alcohol with water, say, 25 per cent. of its weight.
With a little practice, the degree of denitroglycerining required is easily and rapidly
obtained, and the nitro-glycerine dissolved is recouped either by cooling the solution,
or by further diluting it with water, or by distilling over part of the methylic alcohol
until the nitro-glycerine becomes insoluble. In this way, a product can be obtained
which contains only one part by weight of nitro-glycerine for two parts by weight of
nitro-cellulose, and which offers as great consistency as ordinary celluloid. The
product obtained as above described, when brought under steam-heated rollers, gets
freed from adhering methylic alcohol and water (which evaporate), and may be, if the
rollers are kept at sufficiently high temperature, rolled out into sheets of suitable size
and thickness.
A dissolving bath may also be made to extract the camphor_contained in the
explosive compound described in the aforesaid patent No. 1471. For such purpose,
said compound, rolled out into thin sheets, of, say, 4th millimetre thickness, or cut up
into fine grains, is immersed in a bath of bisulphide of carbon, or analogous solvent,
which extracts the camphor without dissolving a notable quantity of nitro-glycerine.
As in the case heretofore cited, a little practice will permit of easily ascertaining when
the operation is at an end. The sheets thus obtained are then brought under steam-
heated rollers, and rolled out into any required thickness.
Dated this 5th day of June 1889.
NEWTON & SON,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Preparation of Explosive Compounds.
I, ALFRED VINCENT NEWTON of the Office for Patents, 6 Bream's Buildings
Chancery Lane in the County of Middlesex, Mechanical Draughtsman, 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 specification of Letters Patent dated 31st January 1888, No. 1471, obtained
on behalf of the communicator of the present invention, I described various modes of
making, from nitro-glycerine and soluble nitro-cellulose, a horny or semi-horny,
explosive compound. I pointed out in said specification, that an addition of camphor,
or other suitable solvent, to nitro-glycerine facilitates the incorporating with the latter
a quantity of nitro-cellulose sufficient to obtain such a product, capable of being cut
up into so-called grains for use in firearms.
By subsequent experiments it has been found that an explosive substance similar to
the one described in the aforesaid patent may he very conveniently produced by other
processes of manufacture, which constitute the subject of the present invention, and
which I will now proceed to describe in the words of my correspondent.
In carrying out my improved manufacture, I either make nitro-cellulose absorb the
exact quantity of nitro glycerine which the final explosive material is intended to
retain, or an excess of nitroglycerine, which in such case is removed in the subsequent
course of manufacture.
The relative proportions of nitro-glycerine and nitro-cellulose are such as are
described in Letters Patent No. 1471, aforesaid, and generally a compound composed
of equal parts by weight of nitro glycerine and nitro cellulose, answers well for
explosive uses. These proportions can of course be varied when explosives of special
quality are required.

page_text: In manufacturing said compound, I make use, by preference, of nitro-cellulose
containing as great a proportion of dinitrocellulose as a wholesale manufacture will
permit. I also use said nitro-cellulose well pulped and wet.
The presence of water in said nitro cellulose, by retarding the dissolving action of
nitro-glycerine and otherwise, facilitates the intimate mixture of nitro cellulose and
nitro-glycerine.
I mix by hand, or any suitable mixing machinery, say, 100 parts of nitro-glycerine
with so much wet nitro-cellulose before described, as contains, say, 100 parts of dry
nitro-cellulose. I operate at the lowest convenient temperature of the ingredients
(say 5° to 10° Centigrade), and continue to mix until only water escapes on squeezing
the material, and all the nitro-glycerine has been well absorbed in the nitro-cellulose.
I then immerse the mass obtained in hot water of, say, 80° Centigrade, taking care,
first, to divide it into small fragments, in order to facilitate the penetration of heat.
Generally one hour's heating suffices, the time of exposure, however, depending on
the greater or lesser division of the mixed material; on the heat of the water bath;
and on the thoroughly uniform distribution of the nitro-glycerine in the pores of the
nitro-cellulose. When the said material has become well gelatinized, so that pressure
will not squeeze out any liquid nitro-glycerine, it is treated between steam-heated
roliers until plates or sheets of uniform horny or semihorny aspect have been obtained,
which are then cut up into so-called grains, or otherwise dealt with, as described in
the aforesaid Letters Patent No. 1471, which also describes the said process of
laminating said material between steam-heated rollers, and generally the process of
manufacture from the gelatinized raw material aforesaid.
The water contained in the aforesaid wet nitro-cellulose is in a great measure easily
extracted in a press or centrifugal apparatus, or by the pressure exercised between
steam-heated rollers; and the remaining portion is evaporated during the rolling-
out process.
The incorporation of nitro-cellulose and nitro-glycerine is still more facilitated by
making use of an excess of nitro-glycerine over and above the proportion thereof which
the final product is intended to contain, but in such case, said excess of nitro-glycerine
has to be eliminated by one of the following processes, viz. :-
First process:-Nitro-cellulose, moist or dry, is allowed to absorb as much of nitro
glycerine as its capillary action will permit, and that operation is performed whilst
the ingredients are kept at the lowest convenient temperature (say 5° to 10° Centi-
grade), in order to prevent nitro-glycerine from exercising any dissolving action on
the nitro-cellulose in which it becomes absorbed, since such dissolving action, by
rendering said nitro-glycerine viscous, would prevent the extraction by pressure, as
hereinafter described, of the excess of nitro-glycerine added. Should nitro-cellulose
be made use of, which, under the aforesaid conditions, is not quite insoluble in nitro-
glycerine, then such insolubility has to be ensured by mixing with the nitro-glycerine,
say, 20 per cent. of its weight of benzol. Such admixture, by lowering the freezing
point of nitro-glycerine, permits of operating at a lower temperature than when
nitro-glycerine is used without benzol, and it should be understood that the lower the
temperature is, the less tendency the nitro-glycerine will have to dissolve even traces
of nitro-cellulose.
The mass obtained by the aforesaid mixing is brought (due care being taken not
raise the temperature) under a press, where the aforesaid excess of nitro-glycerine
is extracted by pressure.
In order to control the extraction of the nitro-glycerine, so
as to arrive at a uniform and desired composition of the final product, the drained-off
liquid is run into a receiver placed on a balance close to said press, and thus the
quantity of nitro-glycerine recovered will be clearly indicated. The mass remaining
after said treatment, is then immersed in hot water, as above described, or otherwise
heated to produce its gelatinization, and it is then subjected to pressure between steam
heated rollers, and generally treated as above described.
This process is advantageous, especially when the nitro-cellulose which forms part of
its composition is to be used in a dry state or slightly damp.
Second process :-I mix thoroughly nitro cellulose dry or damp, or wet, with, say

page_text: two or three times its weight of nitro-glycerino, which is not to be extracted by
pressure, as above described. I then immerse the mass obtained in hot water, as
heretofore described, or otherwise heat it, until it is well gelatinized. It is then
treated between steam-heated or water heated rollers, and rolled out into thin sheets,
or formed, while still plastic, into any desired shape. I then submit it to a process of
denitroglycerinization, which consists in immersing it in a liquid possessing the
property of dissolving nitro-glycerine without dissolving nitro-cellulose. A suitable
liquid of such kind is methylic alcohol, diluted with, say, 25 per cent. of its weight of
water. That liquid, moreover, provides for the facile recovery of the extracted
nitro-glycerine, since it suffices to lower its temperature to, say, 5° Centigrade, when
nearly all the dissolved nitro-glycerine separates, & may be decanted. The time of
immersion needed thus to extract a certain proportion of nitro-glycerine, depends on
the thickness of the material exposed, and must therefore be practically ascertained to
suit each individual mode of operating. Said material is, when denitroglycerinized,
as herein described, treated between steain-heated or water heated rollers, and generally
dealt with as heretofore described.
This process offers the advantage of very easy gelatinization at a comparatively
low temperature, say 50° to 60° Centigrade, and exposure thereto of very short
duration.
Owing, however, to its great simplicity, I generally give preference to the first
above-named mode of operating, viz. :-mixing and incorporating nitro-cellulose of
due composition, as heretofore specified, in a wet state, with only such proportion of
nitro-glycerine as the final product is destined to retain.
Since nitro-cellulose is never, when manufactured on a large scale, a completely
uniform product, the aforesaid material will accordingly slightly vary, as varies
the nitro-cellulose therein contained. The so called insoluble, or trinitro-cellulose,
always contains nitro-cellulose soluble in nitro-glycerine, and, on the other hand, the
so-called soluble nitro-cellulose generally contains some insoluble portion.
The explosive material herein described is prepared and cut up into so-called grains,
or otherwise dealt with, for explosive purposes, as described in aforesaid patent
No. 1471.
Having now particularly described and ascertained the nature of the said Inven-
tion, and in what manner the same is to be performed, as communicated to me from
abroad, I declare that what I claim is :-
The herein-described processes for manufacturing an explosive compound, of horny
or semi-horny consistency, from nitro-glycerine and nitro-cellulose.
Dated this 3rd day of April 1890.
NEWTON & SON,
Agents for the Applicant.