IMPROVEMENTS IN THE MANUFACTURE OF PYROXYLINE AND OTHER NITROCELLULOSE
Year: 1878

page_text: LETTERS PATENT to Frank Wirth, of the Firm of Wirth and Company, Patent
Solicitors, at Frankfort-on-the-Main, in the Empire of Germany, for the Inven-
tion of "IMPROVEMENTS IN THE MANUFACTURE OF PYROXYLINE AND OTHER
NITROCELLULOSE." A communication from the "Dynamite Manufacturing
Company, late Alfred Nobel and Company," at Hamburg, in the Empire of
Gerinany.
Sealed the 10th December 1878, and dated the 24th June 1878.
PROVISIONAL SPECIFICATION left by the said Frank Wirth at the Office of
the Commissioners of Patents on the 24th June 1878.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors; at
Frankfort-on-the-Main, in the Empire of Germany. "IMPROVEMENTS IN THE
MANUFACTURE OF PYROXYLINE AND OTHER NITROCELLULOSE." [A communication
from the "Dynamite Manufacturing Company, late Alfred Nobel and Company," at
Hamburg, in the Empire of Germany.]
Heretofore the cotton or other cellulose used as raw material for the manufacture
of pyroxyline or other nitrocellulose has been employed in an undivided or in an
imperfectly divided state effected by rending or lacerating the said cellulose.
:
This undivided or imperfectly divided form of the raw material has the following
disadvantages, namely:-The "nitration" is an incomplete one, so that even the
best quality of English pyroxyline contains some untransformed cellulose. Further-
more, the washing and the neutralizing is rendered difficult by the coarse form of
the raw inaterial; and finally, the product obtained allows but an insufficient com-:
pression, and consequently a compaiatively low concentration of force.
;
These disadvantages are remedied by converting the cellulose before the "nitra-
tion" into a fine and impalpable powder by the following process, that is to say :-
The vegetable fibre is soaked with diluted sulphuric acid of from 40 to 45° Baumé,
and allowed to remain in contact therewith for some time, the length of which;

page_text: depends on the nature of the vegetable fibre; the fibre is then washed by means of
pure water and dried.
°
Or the fibre may be soaked with a weak acid liquid (water containing 5% of
sulphuric acid) heated to 100° centigrade, and kept at such temperature for a
time.
•
Or the fibre may be dissolved in a mixture of sulphuric acid and water; then
precipitated by mixing with water, and finally dried.
The cellulose treated by one of the above-described methods becomes after drying
a fine impalpable powder.
In lieu of the sulphuric acid a solution of chloride of zinc may be used.
The powder thus obtained is in the well-known manner converted into pyroxy-
line or other nitrocellulose.
I am aware that the fact that cellulose treated by the above-described method is
converted into powder is already known, but the use of such powder for the manu-
facture of pyroxyline is new. The use of such powder has the advantage that a
more effectual explosive compound is obtained, as the "nitration" aud compression
aro more complete, and consequently the concentration of power may be made more
considerable than heretofore.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frank Wirth in the Great Seal Patent Office on the 18th December
1878.
FRANK WIRTH, of the Firm of Wirth and Company, Patent Solicitors, at
Frankfort-on-the-Maine, in the Empire of Germany. "IMPROVEMENTS IN THE
MANUFACTURE OF PYROXYLINE AND OTHER NITROCELLULOSE." A communication
from the "Dynamite Manufacturing Company, late Alfred Nobel and Company," at
Hamburg, in the Empire of Germany.
Heretofore the cotton or other cellulose used as raw material for the manufacture
of pyroxyline or other nitrocellulose has been employed in an undivided or in an
imperfectly divided state produced by rending or lacerating the said cellulose.
This undivided or imperfectly divided form of the raw material has the following
disadvantages, namely:-The nitrification is incomplete, so that even the best
quality of English pyroxyline contains some untransformed cellulose. Furthermore,
the washing and neutralizing are rendered difficult by the coarse form of the raw
material; and finally, the product obtained allows but an insufficient compression,
and consequently a comparatively low concentration of force.
These disadvantages are avoided by converting the cellulose before the nitrifi-
cation into a fine and impalpable powder by the following process, that is to say:-
The vegetable fibre is soaked with diluted sulphuric acid of from 40 to 45° Baumé,
and allowed to remain [in contact therewith for some time, the length of which

page_text: depends on the nature of the vegetable fibre; the fibre is then washed with pure
water and dried.
Or the fibre may be soaked with a weak acid liquid (water containing five per
cent. of sulphuric acid) heated to 100° centigrade, and kept at such temperature
for a time.
Or the fibre may be dissolved in a mixture of sulphuric acid and water; then
precipitated by mixing with water, and finally dried.
The cellulose treated by one of the above-described methods becomes after
drying a fine impalpable powder.
In lieu of the sulphuric acid a solution of chloride of zinc may be used.
The powder obtained by my process or method is converted in the usual well-
known manner into pyroxyline or other nitrocellulose.
I am aware of its being already known that cellulose treated by the above-
described method is converted into powder, but the use of this powder for the
manufacture of pyroxyline has not been heretofore known. The use of such
powder has the advantage that a more effectual explosive compound is obtained as
the nitrification and compression are more completo, and consequently the con-
centration of power may be greater than heretofore.
Having thus fully described the said Invention, and the manner of performing
the same, I wish it understood that I claim, the manufacture of nitrocellulose by
the use of cellulose, which, previous to the nitrification, has, by one of the above-
described methods, been converted into a fine powder.
In witness whereof, I, the said Frank Wirth, have hereunto set my hand and
seal, this Twelfth day of December, in the year of our Lord One thousand
eight hundred and seventy-eight.
FRANK WIRTH. (L.S.)