A Novel Method of Producing variously Colored Objects of Marble- like or other Ornamental Appearance from Rubber and like Vulcanizable Material.
Year: 1899

page_text: Date of Application, 8th Feb., 1899-Accepted, 1st Apr., 1899
COMPLETE SPECIFICATION.
A Novel Method of Producing variously Colored Objects of Marble-
like or other Ornamental Appearance from Rubber and like
Vulcanizable Material.
I, WILHELM LANDAU, of 1, Bismarckstrasse, Friedberg, Hesse, German Empire,
Dentist, 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 has reference to a novel method by which it is practicable to
obtain ornamental and useful articles of the most varied marbled or other
ornamental appearance. With this object, an impression of the desired object is
first taken in plaster of Paris from a model in a suitable mould. When the
model has been removed, one half of the negative impression is filled with damp
strips of rubber or other vulcanisable material of any desired shape, size and
color, and which have been prepared for vulcanisation, the filling being so effected
that the portion projecting from the plaster receives the appearance of the desired
object. Acording to the variation of the different colored rubber or like strips
employed it is possible to produce articles or goods of the most varied appearances,
as for example imitations of agate, coral and ivory, or articles which may be
compared to so-called Japan goods, or it may be mosaic.
When the one half of the negative impression has been filled or packed with the
different rubber strips and these have been united to form one piece by mechanical
pressure, the second half of the mould is placed in position, a corresponding
portion of the negative impression having been previously produced therein by
filling same with wet plaster and pressing it upon the other or model-containing
portion. The halves are then pressed together in a press in order that the rubber
object, may receive a greater compactness and consequently have a better appear-
ance when finished. The whole is then heated in a suitable apparatus to 160°-
165° C., the vulcanisation and hardening of the rubber being complete after about
an hour. After removal and cooling, the mould is taken apart, the article removed
from the plaster cast, cleaned and made ready for the market by any suitable
further treatment.
I will now proceed to give an example of the process above referred to.
The mould may with advantage be in the form of a metal box or cuvette, made
in two parts. The under half of the box consists of a single piece while the upper
half is provided with a removable cover.
The under half is filled with wet plaster of Paris and the waxen, gutta-percha or
the like model after being well coated with oil (oil being preferably also applied
to the surface of the moist plaster) is pressed into the plaster while this is moist,
this being effected in such manner that the portion corresponding to the part of
the rubber article which is to subsequently receive the desired appearance pro-
trudes above the surface of the plaster. The second half of the mould, that pro-
vided with the cover, is then filled with wet plaster, and after the surface of the
model and of the plaster in the lower half of the mould have been well coated
with oil, the halves are pressed together. The portion of the model projecting

page_text: from the under half of the mould becomes impressed in the soft plaster of the
second half; the surplus plaster issues from the interstices which the removable
cover forms with the second half of the mould. When the plaster has set, the
mould is taken apart, and since the model-containing portion of the mould has
previously been well oiled, the parts may be separated without injury to the
plaster. The wax or gutta-percha model is soaked with boiling water, and by this
means becomes softened, and when in this condition it can be readily removed
from the plaster. The whole operation of removal is conducted so quickly that
no plaster is dissolved by the hot water; the oil. coating assisting the removal and
preventing the plaster being dissolved by the water.
In the place of the model, the rubber is now filled into the lower half of the
mould, in such a manner that the portion to receive the desired ornamental appear-
ance projects above the surface of the plaster in the lower half mould, the rubber
having been previously softened in warm water and prepared for vulcanisation.
The subsequent appearance of the article depends chiefly upon this operation of
packing the negative cast. The appearance of the finished article varies, as will
be well understood, according as the rubber is used in the form of cube-shaped
or prism-like or other shaped pieces or strips. The color of the rubber can be
infinitely varied, and the differently colored strips can be combined in any desired
manner, so that any desired imitations of articles of say agate or marble may be
produced; it is also practicable to obtain imitations of precious stones, coral or
ivory by employing correspondingly colored rubber.
When the filling or packing operation is complete, the upper half of the mould
with the lid is again put on and the whole then put under the press in order to
impart a firmer texture to the rubber article; the expressed rubber escapes through
grooves or channels previously cut in the plaster.
The cuvette is then screwed up in a clamp-frame and subjected for an hour to
a heat of 1600-165° C. This is effected in a suitable manner in a vulcanising
apparatus containing a little water, and sufficiently large to receive many moulds
at a time.
After about an hour the vulcanisation is finished. The mould is removed from
the apparatus, allowed to cool and taken apart, the article to be produced being
thus obtained in its unfinished state. The article is then removed from the
plaster cast, cleaned with brush and water, and then finished with files, tools &c.
Finally it is rubbed up with sandpaper and subjected to treatment in a polishing
machine with brushes, oil and emery, and to enhance the polish with chalk and
spirit ground to a fine paste.
Brooches, shirt- and sleeve buttons, hairpins, mounts for cigarette cases, veneer
or facing for small tables and other furniture may be produced from rubber goods
manufactured in accordance with the above described method, according to the
particular manipulation employed. The articles so made are lasting, and so to
speak unbreakable.
The method may be modified by employing other materials, as for example
mother of pearl, small metal plates, mica and the like, in conjunction with rubber
for filling the negative cast. These become incrusted in or united to the rubber
during the vulcanisation, and the beautiful appearance of the finished articles is
thus still enhanced.
Further, any other vulcanisable material besides rubber can be used.
It is not absolutely necessary that the model be made of soft material; for many
articles a wooden, papier mache or metal model may be employed. If such a
model be used it should be well oiled before being pressed into the plaster, in order
that it may be readily removed subsequently.
1.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. Improved method of manufacture of articles of variously colored marbled

page_text: or other ornamental appearance, for example imitations of Japan goods, articles
of agate and marble, mosaic &c. from rubber and similar vulcanisable material,
which method consists in first taking a negative impression from a model of the
desired article and filling or packing therein rubber strips or strips of other
vulcanisable material colored and arranged according to the final effect desired,
insuring the proper location of the strips by mechanical pressure, and finally
vulcanising the rubber or other material, all substantially as described.
2. In combination with the method specified in Claim 1, the employment, in the
packing or filling of the negative cast, of other materials, e.g. mother of pearl
small metal plates, ivory &e. in conjunction with the vulcanisable material, where-
by the same become incrusted in said vulcanisable material and enhance the
appearance of the finished articles, substantially as described.
Dated this 8th day of February 1899.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane; London, Chartered Patent Agents.