Improvements relating to the Production of a Plastic Moulding Material and to Articles made therefrom.
Year: 1891

page_text: Date of Application, 24th Feb., 1891-Accepted, 28th Mar., 1891
COMPLETE SPECIFICATION.
[Communicated from abroad by EMIL SOCHACZEWSKI, of Waltershausen
(Thuringia), in the Empire of Germany.]
Improvements relating to the Production of a Plastic Moulding
Material and to Articles made therefrom.
1, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent
Agents, 45, Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention, and in what manner the same is to be
perfornied, to be particularly described and ascertained in and by the following
statement:-
This invention relates to the production of a plastic moulding material and to
articles made therefrom.
It has heretofore been assumed that burnt gypsum can bear only a small addition
of foreign substances and experience also shows that in the case of an addition
which amounts to more than one-tenth, at most one sixth part of the gypsum
employed the latter binds with great difficulty, moreover it loses the strength which
it otherwise possesses and becomes crumbly and soft.
The method which constitutes the subject of the aforesaid invention enables
gypsum to be mixed with other substances, chiefly consisting of glue and lime, the
quantity of which may be equal to its own the moulding material thus obtained
being plastic, hardening rapidly and presenting a strength and resisting force which
have not hitherto been attained with gypsum and which are sufficient for most
practical purposes.
For producing this result the aforesaid substances are heated to the temperature
of boiling water both before and after the addition of the gypsum.
The method of producing the improved plastic moulding material is as follows:-
Upon part of French or Cologne glue are poured 3 parts of water, and when
swollen it is dissolved in a boiling water-bath. After the complete dissolution the
heating is continued and 14 parts of strongly burnt marble are added while con-
tinually stirring. To this mixture are added 1½ parts of burnt gypsum while
heating and while stirring, the latter operation being continued until the ingredients
of the hot fluid mass have become intimately mixed. For the aforesaid burnt
marble other pure or mixed minerals such as porcelain material may be substituted.
The employment of this material and the manufacture of articles therefrom
differ from the method heretofore practised inasmuch as the moulds are made of
metal and placed in cold water or are otherwise cooled before being used. This
operation has also to take place after the casting until the material has become
quite cool.
For certain purposes, for instance, when the finished articles are to be employed
in hot chambers it may be expedient to add about part of colophony or other
resin in the molten state. But the use of this substance is well known in the trade
and is altogether immaterial to the method and to the success of the same.
The articles made of the improved material, which without being coloured present
the appearance of plaster casts, become in a short time as hard as a stone, and
resist to a high degree even blows of a hammer, so that the improved method by
reason of its economy is well adapted for many uses where gypsum has hitherto
been excluded, more especially as the method of casting is simpler, the time
necessary for the hardening by cooling less than when unmixed gypsum is
employed.

page_text: Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
First. The method of producing a moulding material of high resisting force for
plastic articles, characterized by adding to 1 part of glue dissolved in a water bath
with 3 parts of water, while continually stirring and while heat is applied, 14 parts
of strongly burnt marble or a mixture of the same with porcelain material, or the
latter alone, and by adding while heat is again applied 1½ parts of burnt gypsum
and intimately mixing the ingredients, either with or without an addition of
about part of dissolved colophony.
Second. The production of articles from the material specified in the first claim
by casting the same in metallic moulds which are strongly cooled in cold water
or in any other suitable manner both before the introduction and after the filling.
Dated this 24th day of February 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicant.