The Treatment of Cellulose for the Manufacture of Cellulose Nitrates or Gun Cotton.
Year: 1891

page_text: Date of Application, 7th Jan., 1891
Complete Specification Left, 7th Oct., 1891-Accepted, 21st Nov., 1891
PROVISIONAL SPECIFICATION.
The Treatment of Cellulose for the Manufacture of Cellulose Nitrates
or Gun Cotton.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this invention which has been com-
municated to me from abroad by Zellstoff-fabrik Waldhof of Waldhof near
Mannheim in the Empire of Germany to be as follows :—
The cellulose of commerce is not in a favourable condition for the manufacture of
cellulose nitrates especially hexanitrate or gun cotton. This cellulose obtained
from wood by the sulphite or other known process is usually in the form of a
mixture composed partly of cellulose of varying degrees of purity and freedom from
incrusting matter and partly of various kinds of conglomerates more or less closely
adhering together.
The chemical purity of the matter to be nitrated is of the utmost importance in
the manufacture of a pure cellulose nitrate and the uniformity of the action of the
nitrating agents (nitric and sulphuric acid) and the thoroughness of the washing by
which these acids are subsequently removed from the nitrated product depends in
great measure upon the uniformity or completeness of the mechanical condition of
division of the cellulose employed.
The attempts which have heretofore been made to bring the collulose of commerce
into a condition in which it is free from the defects hereinbefore mentioned have
failed partly because the material employed was not perfectly freed from incrusting
matter and partly because sufficient attention has not been paid to the uniformity
of the mechanical division of the cellulose fibre when subjected to the nitrating
process.
Now the present invention consists in carrying on the chemical treatment of the
raw wood fibre until all incrusting matter and soluble substances are removed and
then most thoroughly washing and drying when the cellulose will be colourless or
almost colourless. It is then converted into a uniform pulverulent mass which
under gentle pressure gathers into flakes but is immediately formed into a loose
uniform paste with water and after nitration washing and drying forms a product
which when tested by heating for a considerable time to about 71 degrees Centigrade
is not decomposed and does not yield a product capable of turning test paper
blue.
The high degree of mechanical division for the purposes of this invention com-
bined with great productiveness is preferably obtained by the employment of the
disintegrating apparatus hereinafter described but any other reducing mechanism
such for example as a carding machine or a tearing machine or devil capable of
producing the required effect may be employed.
The said disintegrator consists mainly of two rings or discs carried on two separate
shafts placed in line with one another and rotating in opposite directions at a speed
of say about 1,500 revolutions or more per minute. These discs carry pins so
disposed that the pins on the one disc pass between the pins on the other disc and
the cellulose being introduced through a central orifice in one of the discs is thrown
outwards by centrifugal force and becomes thoroughly and uniformly comminuted
or reduced by the action of the pins. The cellulose is caused to pass through the
machine say 4 or 5 times or until a sample after undergoing nitrating washing
and drying is found to be of the required quality.
Dated thin 7th dox of Tonu 1801
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London.

page_text: COMPLETE SPECIFICATION.
The Treatment of Cellulose for the Manufacture of Cellulose Nitrates
or Gun Cotton.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex,
Gentleman, do hereby declare the nature of this invention, which has been
communicated to me from abroad by Zellstoff-fabrik Waldhof of Waldhof near
Mannheim in the Empire of Germany, and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
The cellulose of commerce is not in a favourable condition for the manufacture of
cellulose nitrates especially hexanitrate or gun cotton. This cellulcse obtained
from wood by the sulphate or other known process is usually in the form of a
mixture composed partly of cellulose of varying degrees of purity and freedom from
incrusting matter and partly of various kinds of conglomerates more or less closely
adhering together.
The chemical purity of the matter to be nitrated is of the utmost importance in
the manufacture of a pure cellulose nitrate and the uniformity of the action of the
nitrating agents (nitro-sulphuric acid) and the thoroughness of the washing by
which the acid is subsequently removed from the nitrated product depends in great
measure upon the uniformity or completeness of the mechanical condition of division
of the cellulose employed.
The attempts which have heretofore been made to bring the cellulose of commerce
into a condition, in which it is free from the defects hereinbefore mentioned have
failed partly because the material employed was not perfectly freed from incrusting
matter and partly because sufficient attention has not been paid to the uniformity
of the mechanical division of the cellulose fibre, when subjected to the nitrating
process.
The present invention consists in carrying on the chemical treatment of the raw
wood fibre until all incrusting matter and soluble substances are removed and then
most thoroughly washing and drying, when the cellulose will be colourless or almost
colourless. It is then converted into a uniform pulverulent mass, which under gentle
pressure gathers into flakes but is immediately formed into a loose uniform paste with
water and after nitration washing and drying forms a product which when tested by
heating for a considerable time to about 70 or 71 degrees Centigrade is not decom-
posed and does not yield a product capable of turning test paper blue.
The high degree of mechanical division obtained according to this invention
combined with great productiveness is preferably produced by the employment of a
disintegrating apparatus such as that illustrated in Figure 1 of the accompanying
drawings but any other reducing mechanism (such for example as the carding
machine illustrated in longitudinal section in Figure 2 or a tearing machine or
devil as represented in longitudinal and transverse section in Figure 3) capable of
producing the required effect may be employed.
The disintegrator represented in side and end elevation partly in section in
Figure 1 consists mainly of two rings or discs d d' attached to plates a and b carried
on two separate shafts placed in line with one another and rotating in opposite
directions at a speed of say about 1,500 revolutions or more per minute.
These
rings carry concentric lines of pins c about inch in diameter disposed so that the
pins on the one ring pass between the pins on the other ring and the cellulose being
introduced through a hopper e to a central orifice in one of the discs is thrown out-
wards by centrifugal force and becomes thoroughly and uniformly comminuted or
reduced by the action of the pins.
To obtain the cellulose in a fine state of division the materials being chemically
purified and dried as hereinbefore described are caused to pass through the machine
say 4 or 5 times or through a series of machines until a sample after undergoing
nitrating washing and drying is found to be of the required quality.

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
A process for converting sulphite cellulose or cellulose obtained from wood by
any other known process into a condition favourable for the manufacture of
cellulose nitrates especially of pure cellulose hexanitrate (term according to
Beilstein 2nd edition)-(CH(NO3) O"), which process consists in taking
dry cellulose previously entirely freed from incrusting matters and other soluble
constituents and reducing it to such a degree, by means of a suitable reducing
machine (disintegrator, carding machine, devil or the like), that by treatment of a
sample of the so produced comminuted material with nitrosulphuric acid a nitrate
is obtained, which is not decomposed at a temperature of 70 degrees Centigrade,
substantially as herein before described.
Dated this 7th day of October 1891.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, W.C., Agents.