IMPROVEMENTS IN THE MANU- FACTURE AND TREATMENT OF PYROXYLINE FOR THE PRODUCTION OF A SOLID COMPOUND THEREFROM, AND IN THE APPARATUS EMPLOYED THEREFOR."
Year: 1878

page_text: "
LETTERS PATENT to Charles Denton Abel, of Southampton Buildings, in the
County of Middlesex, for the Invention of IMPROVEMENTS IN THE MANU-
FACTURE AND TREATMENT OF PYROXYLINE FOR THE PRODUCTION OF A SOLID
COMPOUND THEREFROM, AND IN THE APPARATUS EMPLOYED THEREFOR." A
communication from abroad by Victor Tribouillet, Manufacturing Chemist, and
Louis Auguste de Besaucèle, Gentleman, both of Paris, France.
led the 27th May 1879, and dated the 10th December 1878.
PROVISIONAL SPECIFICATION left by the said Charles Denton Abel at the
Office of the Commissioners of Patents on the 10th December 1878.
CHARLES DENTON ABEL, of Southampton Buildings, in the County of Middlesex.
"IMPROVEMENTS IN THE MANUFACTURE AND TREATMENT OF PYROXYLINE FOR THE
PRODUCTION OF A SOLID COMPOUND THEREFROM, AND IN, THE APPARATUS EMPLOYED
THEREFOR." [A cominunication from abroad by Victor Tribouillet, Manufacturing
Chemist, and Louis Auguste de Besaucèle, Gentleman, both of Paris, France.
This Invention relates to an improved manufacture of a substance known as
celluloide, compounded of pyroxyline or gun cotton, and other substances which
are employed for imitation ivory and the like.
The present improvements consist, firstly, in an improved manufacture of
the pyroxyline itself; and, second, in the agglomeration thereof into the required
solid form by means of camphor.
For producing the pyroxyline are employed fibrous, vegetable substances, such
as paper, rags, wood, fibrous plants, and the like, consisting in great part of
cellulose and rendered perfectly free from grease. These substances are completely
dried in a stove at a temperature of 212° Fahr., and are then disintegrated by any
suitable known means and converted into pyroxyline. For this purpose the sub-
stances are introduced into a vessel charged with a mixture of sulphuric and
Prine 621

page_text: nitric acids in the proportion of three parts of the former at 66° and 2 parts of the
latter, nitrous gas being dissolved into the mixture in order to render the pyroxy-
line more soluble. The vessel consists of a flat basin of glass, earthenware,
enamelled iron or other material, little or not at all affected by the acids, which has a
double bottom, through which cold water is made to circulate, and which is covered
by a glass dome having, firstly, a hopper closed by a slide at top for introducing
the fibrous substances; secondly, two side openings having caoutchouc sleeves
attached thereto for the introduction of the arms of the operator for working up
the materials in the acid by means of a trowel; and, thirdly, a side discharge
opening, through which the material when sufficiently treated is discharged into a
strong enamelled iron perforated cylinder, in which it is subjected to pressure by a
piston of granite or other suitable material worked by a screw press, so as to remove
the greater portion of the acid, which is collected in a vat. When sufficiently pressed
the material is removed through a side door, and is placed in a second vessel of the
same construction as first described, containing acid mixture of greater strength
than in the first where it is worked up until the cellulose is entirely converted.
The acids may be economised by employing a bath already used and raising its
temperature to 30° to 35° centigrade, but in that case the mass must be allowed to
remain several hours. The temperature and duration of the immersion can be reduced
by adding to the bath about one third of its weight of a mixture of sulphuric and
nitric acids, or of the latter alone, or of sulphate or bi-sulphate of soda or any other
sulphate soluble in water in a perfectly dry and powdered state. The mass is then
subjected to the action of a second press, constructed as above described, for
removing the greater part of the acids; and it is then washed, for the entire
removal of the free acids.
For this purpose for the first washing a vessel of the same construction as those
for treating with the acids is used, after which the mass is again pressed, and
is rinsed in a wooden vat containing acidulated water. It is then placed in
wooden vats with perforated bottoms covered with wire gauze or felt, so that the
water runs through the mass into a trough below; or a number of such vats
mounted on wheels may be arranged on an incline in terrace form, so that the
water passing from the vat above runs into that below, and so on, thus subjecting
the pyroxyline to a progressive washing from one stage to another. Lastly, the
mass is rinsed in water containing a small quantity of carbonate of soda or
ammonia, or silicate of soda, and then in pure water, after which it is dried either
by a press or by a centrifugal machine.
The acids after use may be employed for various purposes, such as the manu-
facture of sulphuric acid; and the acids mixed with water may be used for the manu-
facture of oxalic acid, dextrine, &c.
Thus the solution can be saturated with sulphate of lime, the soluble nitrate
being collected and mixed with that derived from the wasting of the sulphate and
cvaporated for the market; or again, these nitrates can be treated with sulphate of
potash or soda, giving a nitrate which is rendered solid by evaporation and
crystallisation.
For the production of the solid pyroxyline compound the pyroxyline is mixed with
liquid or solid solvents, the former being preferred for producing the compound in
a transparent or translucent condition.
For producing imitation ivory and the like, camphor ground in water is used,
from 42 to 50 parts thereof being mixed with 100 parts of the pyroxyline. This
mixture is wrapped in a strong envelope and placed between the plates of a hot
press similar to that used in the manufacture of stearine, the plates being arranged
horizontally and made hollow and heated by steam. The press is surrounded by a
sheet iron casing provided with a door, and also an opening connected by a pipe to
a condensing chamber, in which the vapours of camphor and of other substances
evolved in the press are condensed, such chamber being provided with a number
of shevles arranged in zig zag position, over which water is made to flow.
The compound having been removed from the press is then subjected to farther

page_text: pressure in cylinders heated by a steam jacket, and is then placed in a chamber
heated by a steam jacket, in which a partial vacuum is maintained by a pump, and
containing substances such as chloride of calcium or concentrated sulphuric acid for
absorbing all moisture. The thin discs of the compound can then be united
together by moistening their surfaces with alcohol and subjecting them to pressure
in the presence of heat.
The compound, which may contain resinous or colouring matters, may be
rendered less inflammable by washing the pyroxiline in the first instance in a solution
of silicate of soda, and mixing therewith phosphate of ammonia or soda and
borate of lead or the more fusible solvents used by painters on porcelain or glass.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles Denton Abel in the Great Seal Patent Office on the 10th
June 1879.
sex..
"
CHARLES DENTON ABEL, of Southampton Buildings, in the County of Middle-
IMPROVEMENTS IN THE MANUFACTURE AND TREATMENT OF PYROXYLINE For
THE PRODUCTION OF A SOLID COMPOUND THEREFROM, AND IN THE APPARATUS
EMPLOYED THEREFOR." A communication from abroad by Victor Tribouillet,
Manufacturing Chemist, and Louis Auguste de Besaucèle, Gentleman, both of Paris,
France.
This Invention relates to an improved manufacture of a substance known as
celluloide, compounded of pyroxyline or gun cotton and other substances for pro-
ducing imitation of ivory and like materials. The present improvements relate to
the manufacture of the pyroxyline itself, and to its composition with camphor and
like substances in the solid forms desired. For the production of pyroxyline the
raw materials employed are paper and rags of cotton, linen, and hemp fabrics
thoroughly cleaned, and especially free from fatty matter; certain white woods,
stalks of fibrous plants, such as esparto, which consist chiefly of cellulose, and
contain few incrusting ingredients. The cellulose material is thoroughly dried in
a stove at a temperature of 212° Fahr.; then disintegrated and bruised in a mill or
other suitable apparatus, after which it is kept free from damp, and finally trans-
formed into pyroxyle by means of the following apparatus:-There are required
three basins A, a vertical section of one of which is shewn at Fig. 1 of the accom-
panying Drawings, and a plan at Fig. 2. Each of the basins may be made of one
or more plates of glass, or plate enamelled with a glaze containing little alkali or
lead to prevent it from being attacked by powerful acids. They might also be
made of ceramic ware, or of thin cast iron enamelled or not. Each basin rests on
a lower basin made of wood or metal, through which circulates a gentle stream of
water to the bottom of the basin A. Each basin is enclosed by a glazed cover V
to prevent the weakening of the acids by access of damp air, and to protect the
workmen from the fumes. This cover is surmounted by a hopper T closed at its
bottom by a valve s, and it has a lateral orifice C opening like a window, and two
circular orifices o, to which are attached sleeve tubes m of caoutchouc or gutta-
percha, by which the arms of workmen can be inserted to agitate the contents.
Two of the basins serve for treatment with acid, and the third for washing with
pure water. There are also required three cylindrical vessels, one of which is shewn
in vertical section and sectional plan at Figs. 3 and 4. The internal diameter is
the same throughout, but the external diameter increases downwards. These
vessels are made of cast iron enamelled both inside and outside, and are per-
forated, and especially at the lower parts, with numerous small holes, permitting
issue of liquid when the contents are subjected to pressure. The pressing piston-P
is of cast iron enamelled, or of ceramic ware or granite provided with a rod t.
material pressed in the cylinder is taken out by a door E extending half round the
circumference, and about three fifths of the height. This door is securely bolted to
resist pressure. For each cylinder is required a screw press of any known kind.
They act on the pistons of the vessels D, which are placed on a stage for the
extraction of liquid from the material treated. Two of the basins of the cylinders
and of the presses are employed for treatment of the cellulose with acids; the third
of each for preliminary washing with water. For the succeeding washings are
employed wooden vessels F, shewn in vertical section at Fig. 5. The bottom only
is perforated with small holes, and covered with fabric G of cloth, felt, or the like,
which acts as a filter retaining the pyroxyle. Under the filter is placed a receiver H
of wood to receive the liquid, which has passed through the pyroxyle. The size
and number of the washing vessels and receivers depend on the extent of the
manufacture. The washing vessels may be arranged in stages, so that the liquid
The

page_text: from each receiver may flow by gravity through the successive masses of pyroxyle.
The washing vessels may in such case be of less height, as shewn in Fig. 6, and
may have unequal wheels, so that they may be placed on an incline, and run there-
from when the washing is completed.
In conducting the manufacturing operations the acids employed are contained in
close vessels placed at a higher level than the basins, so that their contents may
flow into the latter by gravity. The acid vessels may be of enamelled iron, or of
ceramic ware, or thin granite. The acid liquid consists of 3 parts sulphuric acid at
66° to 2 parts of the concentrated nitric acid of commerce. In the mixture is
dissolved nitrous gas, which renders the pyroxyle more soluble. Fig. 7 is a general
plan of the arrangement of the factory. The acid mixture cooled to 45° to 55°
Fahr. is introduced into the second basin A² to a depth of an inch or more. Into the
first basin A is introduced a somewhat larger quantity of acid that has already been
used, and in this is immersed the dry divided cellulose introduced by the hopper T,
Fig. 1, in such quantity as the liquid will moisten. An operator then passing his arm
into one of the sleeve tubes m violently stirs the mass for 10 to 15 minutes, after
which the whole contents are placed in one of the cylinders D₁; he then introduces the
piston P, and puts the press X' in action. The liquid pressed out is received in a special
reservoir. The press is then unscrewed, the piston is removed, and the pressed cake
is taken out by the side door and plunged in the concentrated acid in A². A sort
of trowel worked by the hands inserted at the sleeve tubes breaks up the cake.
Stirring is continued until the cellulose is quite dissolved, the mass is discharged
into the second cylinder D-and-subjected-to-a-considerably-greater-pressure-than-
in the first cylinder. The acid liquids pressed out are charged into the first basin
A¹ to act in the first place on the cellulose. The cake of pyroxyle remains impreg-
nated with about one third of the acid employed. Acid may be economised by
employing a bath of that which has previously served, raising its temperature to
about 50° Fahr., but the material must be kept for several hours in this bath. The
temperature and the time of immersion may be reduced by adding to the bath that
has served about one third of its weight of a mixture of nitric and sulphuric acids,
or sulphuric acid alone or sulphate or bisulphate of soda, or any other sulphate
soluble in water adding it quite dry in powder. After its transformation into
pyroxyle, the material is pressed as already described. The washing of the
pyroxyline is intended to clear the nitrated cellulose from the acids which would
destroy it and render it spontaneously combustible, and at. the same time to collect
those acids which if run to waste would be noxious. The first washing of the
cakes charged with concentrated acid is effected in a basin Z, Fig. 7, like those
employed for treating the cellulose; and it is then pressed in the cylinder Ds. For
the second washing the cake is divided in a vat of wood, containing acidulated
water, then the whole is charged into the first of the wooden filters F¹ mentioned
above. The washing then proceeds methodically, that is to say, the first becomes
the second F2, then the third F³, the first receiving the washing liquid from the
second, the second from the third, and the last receiving pure water. The washing
might if required be rendered more complete by employing three or four basins
with a like number of presses. Finally the material is washed in water containing
a very small proportion of carbonate of soda or ammonia, or rather silicate of soda;
and then with water only, the greater part of the moisture being then removed
from the pyroxyle by means of a centrifugal machine or strong pressure. The
pyroxyline is kept for further use iminersed in water. The acids which cannot
further serve for treating the cellulose may be employed for various purposes,
particularly for the manufacture of sulphuric acid. The liquor from the washings
can be used for the manufacture of oxalic acid, dextrine, pickling liquor and other
purposes. From the acid waste by saturation with carbonate of lime may be
collected the soluble nitrate, to which may be added sulphate from the washing;
the whole may be subjected to evaporation and disposed of. Or the nitrates may
be treated with sulphate of potassa or soda, so as to produce nitrates solidified by
evaporation and crystallisation.

page_text: As the cost of pyroxyline is greatly enhanced by the large quantity of acid
required for its production, it is of importance to economise this expenditure by
mixing with the sulphuric and nitric acids that have been already used and have
consequently become weakened, a variable quantity of bisulphate and a little
nitrate of potassa or soda. These salts should be separately dried at a temperature
which does not decompose them, and then pulverised. Sufficient concentration is
thus obtained to enable the acids to be used several times in treating cellulose.
For the alkaline, bisulphate and nitrate may be substituted a proportion of nitric
acid at 45° to 48° Beaumè, and sulphuric acid a few degrees above 66°. By treating
the acids in either of these ways they become finally available for the production
of nitric acid, by adding the nitrate of potassa or soda. The sulphuric acid
assisted by heat dissolves the salt leaving the nitric acid free, which is separated
by distillation. Should it be preferred to prepare the pyroxyline by the old
method, that is to say by treatment with a nitrate and sulphuric acid, the operation
may be conducted as follows:-The pulverised nitrate is mixed with the acid in a
vessel, where after agitation the mixture is allowed to settle. The liquid portion is
decanted into a vessel where the cellulose is immersed in it. After removal of the
pyroxyline, the liquid as well as the deposit is heated and treated in the usual way
for production of nitric acid. The acid liquors after having transformed cellulose
into pyroxyline, may also be applied in the treatment of phosphate of lime, to
produce a soluble bi-phosphate with sulphate and nitrate of lime. The cellulose in
the cheap condition of thin unsized paper, cotton waste, or rags is treated in the
known manner with suitable proportions of acid at the usual temperatures, and for
the usual periods in apparatus consisting of a large basin heated by steam pipes at
the bottom, and of a number of baskets or vessels of enamelled wire or perforated
plate, or of ceramic ware. One of these vessels is shewn in sectional plan at Fig. 10.
It is of segmental form with its side perforated. This being charged with the
cellulose in a state of division, is immersed in the acid bath and agitated. After
the cellulose is transformed into pyroxyline the vessel with its contents is placed in
a sloping position to let it drain, and then a number of the vessels are placed on a
centrifugal machine for the more complete expulsion of moisture. After this the
vessels are plunged in a basin containing the acidulated water coming from the
other basins. All this apparatus is arranged within a glass chamber, the manual
operations being effected by means of flexible sleeve tubes, as above described,
attached to holes in the sides of the chamber. The vapours are conducted from
the chamber to a condenser. The vessels or baskets containing the pyroxyline to
be washed are introduced successively into basins mounted on trucks, the washing
being carried on methodically, that is to say, when the first vessel or basket is
taken from one of the basins, the second takes its place and so on.
The pyroxyline is bleached by permanganate of potassa and sulphurous acid.
For 4 cwt. of pyroxyline we dissolve in water about 1 lb. of the permanganate, mix
the whole with 2 to 3 tons of water, agitate and blow through the mass a current
of sulphurous acid till the bleaching is complete. This may be done in a vat with
revolving agitators or in a rag mill, whereby the pyroxyline is at the same time
reduced to pulp. Instead of the current of sulphurous acid sulphuric acid and salt
may be employed, mixing about 150 lbs. of the former and about 60 or 70 lbs. of
the latter with the mass containing the permanganate; or instead of these materials
about 5 lbs. of hyposulphite of soda, with about 50 gallons of water, and 11 lbs. of
hydrochloric acid may be added slowly to the mass under agitation, causing the
colour given by the permanganate to disappear entirely. Hyposulphite alone may
be used for bleaching, or for final bleaching after a preliminary bleaching, as above
described.
The apparatus employed in compounding the pyroxyline are as follows:-1, a
paper or rag mill of beater to bruise the pyroxyline and camphor; 2, an apparatus
similar to the heated presses used for the manufacture of stearine with the following
modifications, as shewn in Fig. 9; a, the cakes, rectangular, square, or round, are
placed horizontally to avoid a preliminary pressure which solidifies the mixture of

page_text: camphor and pyroxyline; b, the press, which may be a screw or hydraulic, is
entirely surrounded by a casing of plate provided with a door. The rod of the press
passes through a stuffing box in the casing 3; at the side of the casing an opening
connected to a coil for condensing vapours 4; a chamber with which the coil com-
municates for receiving the condensed camphor and other solid matters. This
chamber, shewn in section at Fig. 8, is provided with removeable trays over which
water flows; 5, a press with steam heated rollers to complete the compression pre-
viously made; 6, moulds of various forms; 7, an air pump to exhaust the chamber;
8, a stove or chamber, having a capacity of about 100 cubic feet, made with tight
joints, having a casing for steam or hot air to heat the exterior, while steam or hot
air pipes heat the interior. A large opening permits the placing or removal of the
trays, and it is closed quite tight so that a vacuum can be maintained within ;
9, lastly, a still and its condenser.
The pyroxyline is treated as required with solid or liquid solvents. The liquid
are to be preferred for the production of transparent and even translucent pyroxyline,
for the solution can be filtered and then distilled in an alembic to remove the solvent,
the pyroxyline being then in a state of paste, which can be moulded and then com-
pletely dried. For imitations of ivory and other opaque substances camphor is
employed, which is bruised with water, 42 to 50 parts of camphor being added to
100 parts of pyroxyline, both being considered as dry. After a thorough mixture
the material is enclosed in strong fabric and placed in a hair bag between the plates
of the heated press, where it is pressed for an hour or more. The cakes left in the
-fabric-covers-may-then-be-subjected-to-the-action-of-the-hot-roller-press,_and_then_
placed in the vacuum chamber in presence of absorbents, such as chloride of calcium
or concentrated sulphuric acid to remove all moisture. During the hot pressing
superheated steam or air or liquid heated above 212° Fahr. may be employed, the
higher temperature being required to effect the solution of pyroxyline in camphor.
The thin plates can then be united by heat and pressure, moistening them or not
with alcohol, ether, and the like. Into the products may be introduced any resinous
or other substance, or colouring matter, making paste of uniform colour, or
spotted, or marbled. The pyroxyline is rendered less combustible by washing it
before compounding in a solution of silicate of soda, and introducing into it phos-
phate of ammonia or of soda, or borate of lead, or the more fusible fluxes used for
painting on porcelain or glass. As pyroxyline is not readily attacked by acids, it
may be used as a material for many parts of the apparatus employed for its manu-
facture.
Having thus described the nature of the said Invention, and in what manner the
same is to be performed, as communicated to me by my foreign correspondents, I
claim in respect of the manufacture and treatment of pyroxyline,
First. The combination of processes herein described for the production of pyroxy-
line and solid compounds therefrom.
Second. In the processes referred to in the preceding claim, the use of apparatus
constructed and operating as herein described.
Third. Economising the acids used for conversion by employing the liquor
resulting from successive washings, and reinforcing the same by the addition of acids
or dry salts, as herein described.
In witness whereof, I, the said Charles Denton Abel, have hereunto set my
hand and seal, this Ninth day of June, in the year of our Lord. One thou-
sand eight hundred and seventy nine.
CHA. D. ABEL. (L.S.)