Improvements in the Manufacture of Plastic Mixtures or Compounds.
Year: 1896

page_text: Date of Application, 14th Feb., 1896-Accepted, 25th Apr., 1896
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Plastic Mixtures or
Compounds.
I, LOUIS FRITZ ALBERT MAGDOLF, of 144, Reichenbergerstrasse, Berlin, in
the German Empire, Manufacturer, 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 preparation of homogeneous mixtures
or compounds adapted for use in the manufacture of moulded articles of all kinds
by pressure. Such mixtures must necessarily be composed of binding and filling
materials and many suggestions have already been made for the composition of such
mixtures.
Hitherto in manufacturing plastic masses, resins or other binding materials such
as casein, albumen and the like have generally been employed with cellulose,
wood-pulp, saw-dust and other waste products, which have a great affinity for
water as filling material.
These mixtures and others which have been used for the same purpose all
possess the great disadvantage that they are not homogeneous and are not mixed
in proportions which are suitable to the purpose for which they are required and
consequently articles moulded from such materials by pressure are neither
homogeneous in structure nor of very good appearance.
According to this invention a homogeneous mixture, composed of binding and
filling materials in the requisite proportions and adapted for use in the manufacture
of moulded articles, is obtained by employing as a binding material shellac, copal,
dammara resin, realgar gum, elemi, mastic, and the like, and as filling material
substances which are unaffected by water such as finely ground chalk, kaolin, glass,
infusorial earth and clay (burnt or unburnt) slate or minerals, the mixture being
manufactured by the following process:-
The binding material, for instance dry resin, is dissolved in alcohol or its
products such as ether or chloroform, that is to say, in solvents which combine with
water. The filling material, ground as finely as possible, is then mixed with the
above solution and the proportions of the two substances forming the mixture are
determined by the specific gravities of the two substances in a dry condition, that
is to say: If the binding material bas a specific gravity when dry of 1 and the
filling material has a specific gravity when dry of 2 then one part of the binding
material is mixed with 24 parts of the filling material.
The mixture of binding and filling materials or of the solution of the binding
material with the filling material is effected by constant stirring by means of
suitable devices.
When colouring matters are added to the mixture their specific gravity is
reckoned together with that of the filling material when deciding the proportions
to be used.
When this mixture of binding and filling material in proportions relative to
their specific gravity is obtained as above described, it is stirred with the addition
of water until the binding material separates with the filling material from the
solvent, for instance, alcohol. By this means a deposit is obtained of finely divided
and finely distributed material such as, for instance, shellac and a filling material
with or without colouring matter, which are intimately bound together and form a
thick pulp in the water which contains the solvent for instance alcohol, that is to

page_text: say, in other words, the binding material is not separated from the filling material
by the precipitation.
The pasty mass obtained in the above described manner is then separated from
the water employed for precipitating the solvent of the binding material, compressed
in order to remove any water and solvent which may still remain in the same, and
then dried and finely powdered so as to form the finished material.
The powder obtained in this way and which is homogeneous in structure is
introduced into moulds (after being in some cases heated beforehand) for the
manufacture of articles of all kinds in the ordinary manner.
It will be understood that the moulds must be heated sufficiently to melt the
finely divided and evenly distributed binding material so that it becomes intimately
united with the filling material.
The above described compounds or mixtures are suitable for the manufacture of
buttons, handles for umbrellas, sticks and doors, insulating bodies for electrical
purposes and particularly as a substitute for hard rubber, horn and the like.
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 :-
The manufacture and use of homogeneous mixtures suitable for the manufacture
of moulded articles of all kinds, such manufacture consisting in intimately mixing
together the binding material, the filling material and, if desired, colouring matters, all
in a finely divided condition and in proportions corresponding to their respective
specific gravities in the dry condition, the binding material having been first dissolved
in a solvent which combines with water such as, for instance, alcohol, and in them
adding water to the mixture with constant stirring until the binding material and
the filling material with the admixed colouring matters have become intimately
combined with one another and have been precipitated, in the water containing the
solvent, as a thick pulp which is then removed from the water or freed from the
same, dried and finely powdered, substantially as described.
Dated this 14th day of February 1896.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.