Improvements in or connected with, and Apparatus for, the Obtainment or Extraction of Gutta Percha or the like.
Year: 1892

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c. Act, 1883) as allowed by
the decision of the Chief Examiner of the 26th day of August 1897.
Date of Application, 14th June, 1892
Complete Specification Left, 14th Mar., 1893-Accepted, 13th May, 1893
Improvements in or connected with, and Apparatus for, the
Obtainment or Extraction of Gutta Percha or the like.
I, HIPPOLYTE EUGENE SERULLAS of 20 Rue Moliére Paris in the Republic of
France Chemist do hereby declare the nature of my invention to be as follows:-
This invention relates to a process for the extraction of the gutta percha or the
like which is contained in the leaves stalks or other parts of the gutta percha or
like plant which may be readily gathered. I will refer to the product as gutta
percha.
It is well known that the process now in use for the extraction of gutta percha
entail the destruction of the trunk or stem of the plant although it is possible to
extract gutta ercha from other parts of the plant without the necessity of
sacrificing the trunk or, stem.
The process of extracting gutta percha according to this invention has for its
object the direct elimination of the gutta percha from the dried and pulverized
parts of the plant by the aid of a solvent such as toluene.
If toluene be taken as a solvent and the toluene solution of gutta percha be
distilled under certain conditions for example by means of steam, toluene is
separated and may be again employed.
Or the gutta percha may be precipitated from its solution for example by means
of a liquid such as methylated spirit, or in a current of ammonia gas capable of
being entirely regenerated. If the material before being subjected to the dissolving
agent such as toluene be triturated in water with certain agents such as soda or
potash (and afterwards desiccated or not) the draining of the said material is more
readily accomplished.
The following is a description of an apparatus suited for the purpose of carrying
this process into effect but I do not confine myself to details of construction which
may be varied as desired.
This apparatus comprises a digester for holding the material to be treated and
provided with a jacket; a reservoir (with a like jacket) for the toluene, a
refrigerator, and a still for the gutta percha.
The digester contains an agitator with paddles or any other like arrangement
operated by suitable mechanism, and a filter which may be placed between two
perforated plates.
There is an inlet (capable of being hermetically closed) for the introduction of
the material to be treated. Into the digester pass two pipes for connecting the
upper art thereof with the toluene reservoir one of the said pipes being a syphon.
At the lower part of the digester is a pipe with a cock and communicating with the

page_text: still for the discharge of the toluene solution of the gutta percha. It is preferred
to place a decanting arrangement between the digester and the still. A pipe
conducts vapour to the interior of the digester below the filter and the second pipe
discharges it into any suitable refrigerator.
The digester is warmed by a jet of steam introduced into the jacket by a pipe
and discharging by another pipe each of these pipes being provided with a cock.
A like arrangement may be applied to the toluene reservoir which latter also has
a manometer.
The
The still is provided with a coil supplied with steam and perforated to produce
suitable discharge of vapour which passes off by an elbow pipe above.
working of the apparatus may be described under two heads the first treating of
the dissolving of the gutta percha, the second aiming more especially at the recovery
of the toluene employed as the dissolving agent.
THE DISSOLVING PROCESS.
'
The material to be treated (such as leaves stalks or other parts which may be
readily gathered from the gutta percha plant) are preferably pulverized and placed
in the digester on the filter the digester is then closed and the toluene is jassed
from the refrigerator into the reservoir where it is heated by steam which passes
through the jacket thereof.
ป'
By means of the syphon the contents of this reservoir pass into the digester
where the complete heating of the toluene is accomplished by the steam passing
through the jacket thereof.
The toluene thus introduced into the digester is intimately mixed by means of
the agitator with the material to be treated. The agitator by constantly stirring
the mass hastens the dissolving action of the toluene. At the end of an hour or
thereabouts a fresh supply of toluene may be introduced which may be accomplished
automatically by regulating the syphon and the flow from the refrigerator into the
reservoir. Some time after the supply of toluene has been introduced the cock on
the pipe which leads to the still is opened so as to discharge the toluene solution
into the said still. The cock is then closed and fresh toluene is admitted into the
digester to effect a further dissolving from the material contained therein. This
operation is repeated until the material is completely exhausted of its gutta percha.
Three successive draining operations usually suffice for causing the gutta percha
contained in the material under treatment to pass completely into solution.
Although the dissolving operation of the toluene may be effected without heat it
is preferred to employ heat as described.
After the dissolving has been effected the still contains a toluene solution of
gutta percha and the digester contains a mass drained of the dissolved gutta percha
but still containing some toluene.
The rest of the process consists in distilling the solution so as to obtain the
gutta percha from the solution and recover the toluene. It is also necessary to
recover the toluene contained in the drained mass. This recovery of the solvent
is necessary in order to reduce to a minimum the cost of extraction.
THE RECOVERY PROCESS.
To recover the toluene from the drained mass a jet of steam is caused to pass up
through the bottom of the digester which steam removes the last traces of toluene.
Pure toluene boils at about 110° C. but it is found that it can be completely and
readily withdrawn by a current of steam at 100° C. The toluene contained in the
drained mass is thus removed by a jet of steam and if a refrigerator is fitted to the
outlet pipe it may be readily condensed.
In like manner the toluene is separated from the toluene solution contained in
the still. A jet of steam is introduced through the perforated coil therein causing
the separation of the toluene which may be recovered in a refrigerator connected
for this purpose to the outlet pipe from the still.
The toluene thus withdrawn condenses in the refrigerator (or refrigerators)
above a layer of water where it is easy to separate it by simple decantation. It

page_text: may be then dried by leaving it for some hours in chloride of calcium; but in
practice this decantation is not indispensable as the recovered toluene may be used
immediately after distillation and may be forced by a pump or other suitable
means to the refrigerator for further use.
The gutta percha which remains as a residue on the water of condensation in
the still may be conveyed to a drying apparatus analogous to those employed for
refining gutta percha.
In the working of the apparatus there should be no communication between the
digester and the outside air so as to avoid all possible loss through. leakages; the
arrangement of the apparatus as described accomplishes this result.
The siphon
introduces intermittently the toluene previously warmed in the reservoir. Moreover
the elastic force of the toluene vapour in the digester need not be feared since if
there be an excess of pressure in the latter the toluene vapour passes up by a
pipe into the reservoir and from thence if necessary into the refrigerator in
communication therewith where it is condensed and falls back into the reservoir.
As a modification of the process hereinbefore described gutta percha can De
obtained by submitting the pulverized leaves or the like for a period say of
two hours or less to the action of an alkaline lye kept at a temperature of
about 110° C. and at a pressure of about 6 atmospheres the said solution containing
preferably a quantity of potash or soda equal to say about three per cent. by
weight of the material to be treated after the said material has been dried at say
about 100° C. After this the mass is separated from the liquid while still warm
by filtration or other means and is then washed with water preferably warm.
After this washing it is drained by an ammoniacal copper solution and when it
ceases to yield anything to this liquor it is washed in ammoniacal water.
resulting solid material which remains as a residue is gutta percha which may then
be treated in-a current of steam and dried by suitable means such as those usually
employed for the purification of gutta percha in order to obtain it entirely free
from ammonia and sufficiently rid of the water which it may have absorbed during
the previous operations.
Dated this 14th dor of Tune 1900
The
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in or connected with, and Apparatus for, the
Obtainment or Extraction of Gutta Percha or the like.
I HIPPOLYTE EUGENE SÉRULLAS of 20 Rue Moliére Paris in the Republic of
France, Chemist 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:
This invention relates to a process for the extraction of gutta percha or like
gums contained in the leaves branches or other removeable parts of the gutta
percha or like plant.
It is well known that the processes now in use for the extraction of gutta percha
or like gums entail the destruction of the trunk or stem of the tree although it 19
possible to extract the gum or gutta percha from other parts of the plant without
injury to the trunk or stem.
The process of extracting the gum according to this invention has for its object
the direct extraction of the gum from the dried and pulverized parts of the plant

page_text: by the aid of a dissolving agent such as toluene which has not heretofore been
employed as a solvent of gutta percha.
If toluene be taken as a solvent and the toluene solution of gutta percha be
distilled under certain conditions for example by driving off the solvent by means
of steam, all traces of toluene can be removed and the solvent thus regenerated
may be again employed.
Or the gum or gutta percha may be precipitated from its solution for example
by means of a liquid such as methylated spirit or in a current of ammonia gas
capable of being entirely regenerated. If the material before being subjected to
the dissolving agent such as toluene be triturated in water with certain agents such
as soda or potash (and afterwards desiccated or not) the extraction of the product
is more readily accomplished.
The accompanying drawing represents in vertical section an apparatus suited for
the purpose of carrying this process into effect but I do not confine myself to the
details of construction shewn in the drawing which may be varied as desired.
This apparatus comprises a digester A for holding the material to be treated and
provided with a jacket A', a reservoir B (with a like jacket B') for the toluene, a
refrigerator C, and a still D, for the gutta percha in solution.
The digester A contains an agitator a with revolving blades or any other like
agitating arrangement actuated by suitable mechanism and a filter f placed between
two perforated plates and is provided with an opening closed by a tight fitting
cover capable of being removed for the introduction and removal of the material
to be treated. Into the digester pass two pipes 61 for connecting the upper part
thereof with the toluene reservoir B the pipe being a syphon. At the lower part
of the digester is a pipe d provided with a cock and communicating with the
still D for the discharge of the toluene solution of the gum. Steam can be intro-
duced into the digester below the filter ƒ through a pipe r and a pipe r¹ is provided
for the escape of the steam into a suitable condenser or refrigerator not shown in
the drawing.
The digester is heated by steam introduced into the jacket by the pipe and
discharged by the pipe cach of these pipes being provided with a.cock. A like
heating arrangement is applied to the toluene reservoir B which latter'also liás a
manometer or pressure gauge m. The still D is provided with a coil e supplied
with steam by the pipe and perforated to produce suitable discharge of steam
which passes off by the elbow pipe. The lower part of this vessel is provided
with a cock g.
.
The operation consists firstly in dissolving out the gutta percha, and secondly in
separating or recovering the toluene employed as the dissolving agent.
THE DISSOLVING PROCESS.
The material to be treated (such as leaves branches or other removeable parts of
the tree or plant) are pulverized and placed in the digester A on the filter f; the
digester is then closed and the toluene is passed from the refrigerator C into the
reservoir B where it is heated by the steam which circulates in the jacket thereof.
When the toluene has risen to a sufficient height to start the syphon the contents
of this reservoir pass into the digester A where the heating of the toluene is com-
pleted by the steam passing through the jacket of the said digester. The toluene
thus introduced into the digester is intimately mixed by means of the agitator a
with the material to be treated. The agitator by constantly stirring the mass
hastens the dissolving action of the toluene. At the end of an hour or thereabouts
a fresh supply of toluene is introduced which may be accomplished automatically
by suitably regulating the height of the syphon band the rate at which the toluene
flows from the refrigerator C into the reservoir B. After the second supply of
toluene has had time to take effect upon the materials the cock is opened so as
to discharge the toluene solution into the still D. The cock is then closed and
fresh toluene is admitted into the digester in order to dissolve the gum Femain-
ing in the materials. This operation is repeated until the material is completely
exhausted of its gum or gutta percha. Three successive dissolving operations

page_text: usually suffice for causing the wholo of the gum or gutta percha contained in the
material under treatment to be dissolved in the toluene.
1
Although the extraction by the aid of toluene may be effected without heat it is
preferred to employ heat as described.
At this stage of the operations the still 1) contains a toluene solution of gum or
gutta percha and the digester A contains materials deprived of gum but still con-
taining some toluene. The subsequent operations consist in distilling the solution
so as to separate or obtain the gum or gutta percha from the solution and recover
the toluene. It is also necessary to recover the toluene contained in the exhausted
materials. This recovery or regeneration of the solvent is necessary simply for, the
sake of economy.
"
THE REGENERATING PROCESS.
To recover the toluene remaining in the exhausted materials steam is caused to
pass up through the bottom of the digester A. By these means all traces of toluene
can be removed from the materials contained in the digester which is heated during
the operation. Pure toluene boils at about 110° C. but it is found that it can be
completely and readily driven off by a current of steam at 100° C. The toluene
contained in the exhausted materials being thus removed by the action of the steam
may be readily separated or recovered by condensation by connecting the pipel
with a suitable refrigerator. In like manner the toluene is separated from the
toluene solution contained in the still 1). For this purpose a supply of steam
introduced through the perforated pipe or coil c carries over the toluene which may
be collected in a refrigerator connected for this purpose with the pipe The
toluene thus withdrawn condenses in the refrigerator (or refrigerators) and floats
upon a layer of water from which it can be readily separated by decantation. It
may be then dried by leaving it for some hours in the presence of chloride of
calcium; but in practice this operation is not indispensable as the regenerated
toluene may be used immediately after distillation and may be forced by a pump or
other suitable means into the refrigerator C for further use.
The gum or gutta percha which remains as a residue floating on the water of
condensation in the still D may be conveyed to a kneading and drying apparatus
analagous to those employed for purifying or refining gutta percha and may be
rolled if desired in order to render it fit for immediate use.
When the apparatus is in action there should be no communication between the
digester and the outside air so as to avoid all possible waste of toluene through
leakages; the arrangement of the apparatus as described complies with this
condition. The syphon intermittently introduces into the digester the toluene
which is previously warmed in the jacketted reservoir B. Moreover the expansive
force of the toluene vapour in the digester cannot do any harm because if there be
an excess of pressure in the latter the toluene vapour simply passes up through the
pipe b¹ into the reservoir B and from thence if necessary into the refrigerator C
where it is condensed and returned to the reservoir B.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I desire to say that I am
aware that a solvent of a wholly different kind to toluene, viz.:-disulphide of
carbon has been proposed to be used in the extraction of gutta percha, but such a
solvent has a deleterious effect on the product and I make no claim to the herein
described process when used with such solvent, but subject thereto I declare that
what I claim is:
1. Extracting gutta percha or like gums contained in the leaves branches and
other removable parts of the plant by the use of toluene as a solvent the said
solvent being separated or regenerated by means of steam substantially as herein-
before described.
2. Extracting gutta percha or like gums contained in the leaves branches and
other removable parts of the plant by the use of a solvent or dissolving agent in

page_text: combination with the regeneration or recovery of the latter by means of steam
substantially as hereinbefore described.
3. The apparatus for conducting the process for extracting gutta percha or like
gums by the use of toluene or other suitable solvent the said apparatus comprising
a digester A for the material to be treated, a reservoir B for the toluene or the
like, and a still D for the distillation of the solvent from the gutta percha or
the like the whole in combination with means for supplying steam for heating the
materials and for the separation or carrying over and regeneration of the solvent
substantially as and for the purpose hereinbefore described and illustrated in the
accompanying drawing.
141
L.-ו
1000
J. H. JOHNSON & Co.,
Agents.