Improved Process and Apparatus for the Extraction of Gutta Percha from the Leaves and Twigs of the Isonandra Gutta and Kindred Plants.
Year: 1896

page_text: Date of Application, 28th Aug., 1896
Complete Specification Left, 22nd May, 1897-Accepted, 10th July, 1897
PROVISIONAL SPECIFICATION.
Improved Process and Apparatus for the Extraction of Gutta Percha
from the Leaves and Twigs of the Isonandra Gutta and Kindred
Plants.
We, SIEMENS BROTHERS & CO., LIMITED, of 12 Queen Anne's Gate, Westininster,
in the County of London, Electrical Engineers, and EUGENE FREDERICK AUGUST
OBACH of 2 Victoria Road, Old Charlton in the County of Kent, Chemist, do hereby
declare the nature of this Invention to be as follows:-
Several processes have already been proposed for extracting Gutta Percha from the
leaves and twigs of Gutta percha trees by means of suitable solvents, and two
different methods have hitherto been employed for obtaining the gutta in a solid
form from these solutions, viz. firstly, the removal of the solvent by evaporation or
distillation, and secondly, the precipitation of the gutta by the addition to the
solution of another liquid in which gutta is insoluble. The first named method
impairs the quality of the Gutta percha and the second is complicated and
expensive.
The present invention relates to a simple but at the same time effective process for
the extraction of Gutta from the leaves and twigs of gutta percha trees, preferably
the Isonandra Gutta of Hooker; it consists mainly in the employment for this
purpose of certain hydrocarbons of the paraffin series, such as are contained in
petroleun, and more particularly the lighter distillates therefrom such as benzoline,
gasolene, rigolene &c. it having been discovered that such hydrocarbons have the
property of dissolving gutta when heated to or near to their boiling temperatures,
and of precipitating it again on being cooled to the ordinary temperature, say about
60° F.
The leaves and twigs are for the above purpose dried by exposure to the air or if
necessary, by a gentle artificial heat on a stove or in a kiln, they are then preferably
passed between revolving steel rollers having only a sinall clearance between then.
In this way the stems and twigs are flattened and the leaves broken and opened up,
but not pulverised, consequently no dust is produced during this operation.
The crushed leaves and twigs are then tightly packed in baskets consisting of wire
guage, perforated metal, or other suitable permeable material and these are lowered
into suitable receptacles. These receptacles, or digesters, which are provided with
side tubes aud condensers, are then tightly closed with lids or covers, and the said
solvent is allowed to run in until the leaves are covered. Steam is now admitted into
the jacket, surrounding the lower part of the digester, and the solvent is kept at boiling
emperature for some time, the condenser acting as a reflux-condenser. After cooling
somewhat, the solution is drawn off through a strainer into the precipitating
vessel, which is provided with a jacket or system of pipes, through which
stream of cold water can be passed. Fresh solvent is then run
n to the leaves in the digester and heated to its boiling
before, the
point as
second solution, "the washings' are mixed with the first,
and both cooled down together for precipitation. Steam is then admitted to the
59
[Dmion 1

page_text: jacket and interior of the digester and the remaining solvent distilled off from the
leaves. The digester is now opened and the basket with the exhausted leaves
removed and replaced by another with fresh leaves. After precipitating the gutta
from the solution, the solvent is drawn off and the precipitate repeatedly washed
with fresh solvent until it is nearly colourless, the remaining solvent is then distilled
off from the precipitate by direct steam. On opening the vessel, the gutta is found
in a plastic state; it may either be compressed into bricks, loaves etc., or else be put
direct into the usual washing machine and subsequently masticated and rolled out
into sheets for further use. The solvent drawn off from the precipitate, can be used
over again until it is nearly saturated with impurities, when it must be redistilled
before being further used. Instead of the liquid hydrocarbons above mentioned,
melted paraffin wax can also be employed for extracting gutta from the leaves. On
cooling, the precipitated gutta remains embedded in the solidified paraffin wax, being
thereby hermetically sealed in and completely protected from the access of air. In
this state it is under very suitable conditions for storage and transport.
Dated this 90th day of August. 1896.
ABEL & IMRAY,
Agents for the Applicants.
Improved Process and Apparatus for the Extraction of Gutta Percha 2
from the Leaves and Twigs of the Isonandra Gutta and Kindred
Plants.
We, SIEMENS BROTHERS & CO. LIMITED, of 12 Queen Anne's Gate, Westminster, in
the County of London, Electrical Engineers, and EUGENE FREDERICK AUGUST OBAOB,
of 2, Victoria Road, Old Charlton, in the County of Kent, Chemist, do hereby declare 2
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:-
Several processes have already been proposed for extracting Gutta Percha from the
leaves and twigs of Gutta Percha trees by means of suitable solvents, and two different
inethods have hitherto been employed for obtaining the Gutta in a solid form froin
these solutions, viz.-firstly, the removal of the solvent by evaporation or distillation,
and secondly, the precipitation of the gutta by the addition to the solution of
another liquid in which gutta is insoluble. The first named method impairs the
quality of the Gutta percha and the second is complicated and expensive.
The present invention relates to a simple but at the same time effective process for
the extraction of Gutta from the leaves and twigs of gutta percha trees, preferably
the Isonandra Gutta of Hooker; it consists mainly in the employment for this purpose
of certain hydrocarbons of the paraffin series, such as are contained in petroleum,
and more particularly the lighter distillates therefrom such as benzoline, gasolene,
rigolene &c. it having been discovered that such hydrocarbons have the property of
dissolving gutta when heated to or near to their boiling temperatures, and of precipitating
it again on being cooled to the ordinary temperature, say about 60° F. or preferably
below. The leaves and twigs are for the above purpose dried by exposure to the air
or if necessary, by a gentle artificial heat on a stove or in a kiln, they are then
preferably passed between revolving steel rollers having only a small clearance between
them.
In this way the stems and twigs are flattened and the leaves broken up, but not
pulverised, consequently no dust is produced during this operation.
The crushed leaves and twigs are then tightly packed in baskets consisting of wire
gauze, perforated metal, or other suitable perineable material and these are lowered

page_text: into suitable receptacles. These receptacles or digesters, which are provided with
side tubes and condensers, are then tightly closed with lids or covers, and the said
solvent is allowed to run in until the leaves are covered. Steam is now admitted into
the jacket, surrounding the lower part of the digester, and the solvent is kept at
5 boiling temperature for some time, the condenser acting as a reflux-condenser. After
cooling somewhat, the solution is drawn off through a strainer into the precipitating
vessel, which is provided with a jacket or system of pipes, through which a stream of
cold water can be passed. Fresh solvent is then run on to the leaves in the digester
and heated to its boiling point as before, the second solution, "the washings" are
mixed with the first, and both cooled down together for precipitation.
Steam is then admitted to the jacket and interior of the digester and the remaining
solvent distilled off from the leaves.
The digester is now opened and the basket with the exhausted leaves reinoved and
replaced by another with fresh leaves. After precipitating the gutta from the solution,
the solvent is drawn off and the precipitate is repeatedly washed with fresh solvent
until it is colourless, the remaining solvent is then distilled off from the precipitate by
direct steam. On opening the vessel, the gutta is found in a plastic state, it may
either be compressed into bricks, loaves etc., or else be put direct into the usual
washing machine and subsequently masticated and rolled out into sheets for further
use. The solvent drawn off from the precipitate can be used over again until it is
nearly saturated with impurities, when it must be redistilled before being further
used. Instead of the liquid hydrocarbons above mentioned, melted paraffin wax can
also be employed for extracting gutta from the leaves. On cooling, the precipitating
gutta remains imbedded in the solidified paraffin wax, being thereby hermetically
sealed in and completely protected from the access of air. In this state it is under
very suitable conditions for storage and transport.
The gutta can be separated from the paraffin wax by treating the latter with
petroleum spirit when the wax is dissolved and the gutta left behind in a finely
divided flocculent condition.
The accompanying drawing shews a convenient arrangement of apparatus for
treating the crushed leaves and stems as above described. D1 D2 are two jacketted
digesting receptacles which communicate by pipes B' B2 6 and 7 with either the upper
or the lower end of a coil condenser C, and also by a pipe 9 with a low level tank T,
and by pipes 2, 1 and 5 with two high level tanks T T³, all these pipe connections
having suitable threeway and other cocks or valves by which the flow of fluid may be
directed as desired. The lower parts of the digesters D¹ D' communicate by pipes 3
with a low level tank T. Pumps P1 P2 are provided to draw the liquid from the
low level tanks T and T and force it up to the high level tanks T, 1 respectively.
The digesters D' D' are provided with pressure gauges G1 G and their jackets have
pipes for circulation of steam or water.
Steam can also be admitted to the interior of the digesters at their bottoms by
pipes 8 and water run off by pipes p provided with cocks. The condenser C, and the
tanks T T T T are provided with air pipes v which preferably are all connected
together and led to a receiver where such vapours of the solvent as they carry can be
condensed and collected.
The process of extraction as carried on with the apparatus may be understood from
the following example. A basket containing dry crushed leaves and stems is placed
in D and either fresh solvent or solvent that has been previously used is run in from
the one or the other of the upper tanks until a small overflow is reached. The
solvent is then heated to boiling by steam admitted to the jacket, the cocks
from B¹ to the lower end of the condenser coil C being open, while the upper end of
the coil is open to the air pipes v.
After drawing off solutions from the digester for precipitation of the gutta as above
described the residue of the solvent is distilled off from the material left in D', steam
being admitted by the pipes and the pipe B' being put in communication with the
upper end of the coil C, while its lower end communicates by pipe 9 with the tank T.
The operations with the other digester D are carried on in like manner, the flow of

page_text: the fluids being so determined by the cocks governing the several communications
that the material may be first subjected to the action of solvent that had been
previously used, and then to that of fresh solvent, which in its turn is used for fresh
inaterial, and so on in regular sequence.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed we declare that what we
claim is :-
1. The herein described process for extraction of gutta percha by subjecting the
dry crushed leaves and stems of plants such as Isonandra Gutta to the action of
certain heated hydrocarbon solvents, and precipitating the gutta percha by cooling
the solution.
2. Apparatus for operating as set forth in the preceding claim, substantially as
described and illustrated by the drawing.
1907
ABEL & IMRAY,
Agents for the Applicants.