A Process for Imparting a Pearl-like Appearance in Various Colours to Articles Made of Horn, such as Combs, Ornaments for the Hair, Fans, and the like.
Year: 1889

page_text: Date of Application, 26th Sept., 1889-Accepted, 28th Dec., 1889
COMPLETE SPECIFICATION.
A Process for Imparting a Pearl-like Appearance in Various Colours
to Articles Made of Horn, such as Combs, Ornaments for the
Hair, Fans, and the like.
I, JUSTE FRÉDÉRIC EDMOND BENARD, of 68, Boulevard Saint Marcel, Paris, in the
republic of France, Comb Manufacturer, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed to be particularly describedt
and ascertained in and by the following statement :-
My invention relates to a process for imparting a pearl-like appearance in white,
blue, green, rose or red colours to articles made of horn, such for example, as combs,
ornaments for the hair, fans and the like.
According to my invention the articles which are to have a pearl-like appearance
given to them are immersed in a suitable alkaline solution, the effect of which is
to saponify the fatty matters which naturally exist in the horn and also those which
have been introduced therein in the treatment to which it has been subjected in
the ordinary flattening operation. These saponified products are carried away by the
washing waters. The fibres of the horn which are more or less twisted or irregular
may already, in this first operation present a slightly pearly appearance. The
article is afterwards submitted to a treatment by which the sulphurous products
contained in the composition of the horn are converted into white sulphate.
Various means may be adopted for obtaining this result; the most simple, however,
consists in placing the article in a medium highly charged with oxygen gas, such
as oxygenated water HO 2.
After a time, varying with the nature of the horn and the temperature, the article
is placed in a 5 to 20 per cent. solution of a salt of lead, cadmium or bismuth, by
preference an acetate or a nitrate.
The deposit, which is yet invisible, of this salt is ultimately changed into a
chloride of the same base in a bath of water strongly charged with hydrochloric
acid HCl. The article is then washed, dried, polished and finished.
To obtain pearly green the hereinbefore described preliminary alkaline bath and
the bath of oxygenated water are not required the articles being, instead, immersed
for several minutes in a bath of pure nitric acid very slightly diluted with water
the articles, after they have been washed, being placed in a bath of acetate or nitrate
of lead, then washed and treated with hydrochloric acid and, finally, after another
washing, dried and polished.
To obtain pearly blue the same operations must be used as for white, but a sufficient
quantity (according to the depth of colour to be produced) of chloride of iron
(Fe 2 C13) must be added to the metallic bath, and to the last bath a sufficient quantity
of yellow prussiate of potash (Fe Cy 2 K Cyx 3 HO) is added.
To produce a red colour the same process is observed as for blue except that the
prussiate is replaced by sulpho-cyanide of potassium KS Cy S.
Abundant, washing should be used in every case.
It is in the last bath that the article assumes all its pearly appearance and its
colour. Each bath should be filtered before and after each operation. The article
of horn remaining for a relatively long time (5 to 6 days) in all these baths has a
tendency to become misshapen and it is only with very great precautions that the
desired result can be obtained. But this loss of time and these difficulties can be
partially avoided by treating these articles under pressure in a digester according to
a known process patented in France under No. 178249.

page_text: .
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
(1) The production on the surface of horn of a pearl-like appearance.
(2) The herein described process of giving a pearl-like appearance to horn.
Dated the 26th day of Santamber 1889
G. F. REDEERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.