Improvements in the Manufacture of a Hard Insulating Material.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of a Hard Insulating Material.
I, RICHARD PAPE, of 183, Oranienstrasse, Berlin, Germany, 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 an improved manufacture, or material, that can
be compressed to a hard solid body and used for insulating purposes.
The material consists of 2 parts of powdered chalk, or magnesia and chalk,
mixed with and worked up with 3 parts of soapstone, in such a manner that the
greasy nature of the soapstone is imparted as much as possible to the powdered
chalk. This amalgamation is performed by means of rotating rollers or drums and
is continued until the powdered chalk or material has a soapy touch. This
mechanical soaping or greasing of the powdered chalk or material has the effect of
producing, when in compressed and afterwards finished picces, a material having a
very fine gloss, which does not crumble or chip away when it is worked up or
tooled, and the tools are not so easily blunted. The powdered chalk prepared with
soapstone as above, can be compressed without crumbling and to a very dense
state.
To the powdered chalk prepared with soapstone, and to give it a binding or
cementing nature, there is added 3 parts of resin or shellac dissolved in alcohol.
The mixing of the prepared chalk with the dissolved resin is done gradually and in
such a manner that by persistent kneading, an even and homogeneous dough is
produced, which is afterwards dried and powdered. After this has been done, the
powder is slowly warmed and constantly stirred until the temperature of about
30° Centigrade is reached. It is kept at this temperature until it is placed into hot
moulds and compressed. The purpose of the constant stirring whilst heating, is to
expel the gases which are formed.
Various qualities of the material can be manufactured by adding to the previously
prepared chalk or lime powder, a portion of very fine suitable fibrous material such
as asbestos.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The herein described manufacture or material for use for insulators for
electrical and other purposes, which consists of powdered chalk, magnesia or lime,
amalgamated with soapstone, in such a manner that the greasy nature of the
soapstone is imparted to a large extent to the whole body, and it is rendered
capable of being moulded and finished; as set forth.
2. The herein described manufacture or material for use for insulators for electrical
and other purposes, consisting of chalk, magnesia, or lime, and soapstone, treated as
described, to which is added resin dissolved in alcohol, the compound being heated
and stirred and compressed in suitable moulds as and for the purposes described.
Dated this 23rd day of November 1891.
CHEESBROUGH & ROYSTON, Fels. Chart. Inst. P.A.,
15, Water Street, Liverpool, Agents for the Applicant.