Improvements connected with the Treatment of India-rubber, Gutta-percha, and other Gums.
Year: 1898

page_text: Date of Application, 16th Feb., 1898
Complete Specification Left, 12th Nov., 1898-Accepted, 17th Dec. 1898
Improvements connected with the Treatment of India-rubber,
Gutta-percha, and other Gums.
We, ROWLAND HARRY BIFFEN, of Emmanuel College, Cambridge, in the County of
Cambridge, Demonstrator of Botany, and ESME WILLIAM HOWARD, of Ravenstone,
Keswick, in the County of Cumberland, Gentleman, do hereby declare the nature of
this invention to be as follows:-
This invention relates to the treatment of india-rubber, gutta-percha and other
gums.
It is well known that the latex which exudes from the trees and contains the gum
also contains a very large percentage of substances which have to be separated to
obtain the gum. Hitherto it has been the usual custom to treat the latex with salt,
acid or other substance or in some other manner in order to coagulate the entire mass
and render it fit for transport. This coagulation of the mass, however, renders the
subsequent separation of the gum difficult and expensive and also necessitates the
transport of large quantities of waste material.
According to our invention we separate the gum from the latex whilst the latter is
in a liquid or semi-fluid condition whereby the necessity for coagulation of the entire
mass is avoided and whereby the bulk to be transported is greatly reduced and
standard qualities of gum can be obtained.
In practice we effect this separation by subjecting the latex to centrifugal action
in a suitable machine in which the impurities being of greater specific gravity than
the gum are thrown off in solution whilst the gum particles collect and form a separate
layer which is skimmed off.
Improvements connected with the Treatment of India-rubber,
Gutta-percha, and other Gums.
We, ROWLAND HARRY BIFFEN, of Emmanuel College, Cambridge, in the County
of Cambridge, Demonstrator of Botany, and Esme WILLIAM HOWARD, of Ravenstone,
Keswick, in the County of Cumberland, Gentleman, do hereby declare the nature of
this invention and in what manner the same 1S to be performed, to be par-
ticularly described and ascertained in and by the following statement :—
This invention relates to the treatment of india-rubber, gutta-percha and other

page_text: It is well known that the latex or milk from which india-rubber is prepared is a
complex emulsion containing in a watery solution albumen, globulin and other
proteids and various ferments and salts, and in which the rubber is suspended in
minute solid particles.
Hitherto it has been the usual custom to treat the latex chemically or in some
other manner in order to coagulate the entire mass and render it fit for transport.
This mode of treatment, however, possesses a number of disadvantages the chief of
which are the following,
(1) A large bulk of foreign material has to be transported with the rubber and
upon this foreign material freight charges and customs dues have to be paid as for
rubber.
(2) The coagulated mass frequently emits a very unpleasant smell and is liable to
fermentation with the result that the quality of the rubber is deteriorated.
(3) The treatment of the mass after coagulation is difficult and expensive and in
the washing process, which forms a part of the treatment for the purification of the
rubber, a certain percentage of pure rubber lost.
According to our invention we obviate all the above disadvantages by separating
the gum from the latex and other impurities whilst the latter is in the liquid or
semi-fluid condition in which it exudes from the trees.
In carrying out our invention the latex diluted with water, when necessary, is
exposed to the action of centrifugal force in a separating machine wherein owing to
the fact that the rubber is of lighter specific gravity than the other constituents of
the latex, the rubber particles separate as a thick creamy mass from the other con-
stituents in solution. This creamy mass is removed and solidified either by pressure,
or by spreading the rubber mass over porous tiles which absorb the small quantity of
water remaining; in this way sheets or blocks of rubber of purer quality than
hitherto can be obtained.
It is to be understood that although we have described our process as being
applied to india-rubber gums the same process may be applied to gutta-percha
and other gums.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
" 1. In the treatment of india-rubber, gutta-percha and other gums subjecting the
latex or milk to the action of centrifugal force, skimming off the rubber from
the other constituents in the latex and then drying the rubber, substantially as
described.
2. In the manufacture of india-rubber the process consisting in separating the
rubber from the latex or milk in a centrifugal machine and then spreading such
rubber over porous tiles, substantially as described.
Dated this 12th day of November 1898.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.