Improvements in and connected with Varnishing in Colours.
Year: 1893

page_text: Date of Application, 10th Nov., 1893-Accepted, 16th Dec., 1893
COMPLETE SPECIFICATION.
Improvements in and connected with Varnishing in Colours.
I, Dr. JACQUES PERL, of Scharnhorststrasse No. 7 Berlin, in the Empire of
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:―
Since the discovery of the celluloid varnishes which has enabled colourless
varnishing to be effected by dipping or immersing the articles to be treated in a
bath of colorless varnish, many attempts have been made to also provide such
articles with a coat of colored varnish in a similar manner.
Of the various methods employed for this purpose, that of coloring the bath of
celluloid varnish was in most cases not successful, because the colored varnish
accumulated at the lower parts of the dipped goods in such a manner as to give
them when dry, a darker appearance than the upper parts; richly ornamented
articles in particular assumed a very irregular coloring.
Attempts have also been made to dip articles that have been previously_coated
with colorless celluloid varnish, in colored solutions and in this manner to dye the
same. But although this method when. properly carried out, is successful, it has
been abandoned for years because the use of unsuitable ingredients led to bad
results. The colored coat always became opaque, and the color was extremely,
sensitive to light.
Now according to the present invention, a perfectly uniform and light-resisting
coat of colored varnish can be applied to smooth and also ornamented articles,
whether the latter be large or small, have a dead or a polished surface.
The articles, especially such of metal, bone, and celluloid, are coated in the
ordinary manner with a colorless varnish, and thoroughly dried for about half-an-
hour at a temperature of 60 Celsius, or for a proportionately longer period at a lower
temperature.
To dye the articles thus prepared, I employ a solution of vegetable, aniline, or
alizarine coloring matters. The solvents which I prefer to employ for these coloring
matters are strong alcohols such as methyl-alcohol, ethyl-alcohol, and amyl-alcohol,
also ethyl-acetate, or amyl-acetate and acetone. The said solution I shall herein-
after term the "coloring bath." The articles having been previously highly
heated, and attached in a suitable manner to wires, or, as in the case of a great
number of articles of small size, having been arranged in bundles or placed in
boxes provided with perforated or draining bottoms, are immersed for an instant
in the cold coloring bath and on withdrawal are freed from excess of the coloring
liquid by energetic centrifugal action or by shaking, and are finally dried at a
gentle heat.
The coloring bath employed according to this invention requires only about
to % of coloring matter in order to produce a rich shade of color, whereas with
the colored transparent varnishes heretofore employed, at least 15 times as much is
necessary to produce an equal result. This fact allows of employing in the process
herein described the alizarine colors which are distinguished for their great
resistance to the action of light, and which could not heretofore be employed for
dyeing metals on account of their extremely small solubility in alcohols.
To obtain a fiery gold color on brass, which shall be absolutely light-resisting,
the following coloring bath is to be employed, viz. :-100 grammes of alizarine red
dissolved in 100 litres of absolute alcohol.
Darker gold shades can be produced by the addition of small quantities of sodium
hydrate, riz. About 20 grammes per 100 litres of coloring dip. Any other alkali
soluble in alcohol can be employed in the place of sodium hydrate.

page_text: It is essential for the production of a uniform coloring without dimness, that the
articles to be treated should be first thoroughly dried, and well warmed, and after
removal from the coloring bath, be well drained by being skilfully swung or shaken,
and that the coloring bath should be free from fat or oil.
All previous attempts-to-varnish-in-colors by dipping, have been frustrated by
the lack of appreciation of these four points.
The light-resisting property of the colored coats produced according to this
invention greatly exceeds, when alizarine colors are used, that of the best
varnishes.
Also the polish of highly polished surfaces remains perfectly unimpaired after
treatment by this process; this has not been the case with varnishes employed as
heretofore.
But the main advantage of my improved process consists in a great saving of
time and labour.
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. An improved process of varnishing articles, especially of metal, bone and
celluloid, in colors, consisting in heating the articles that have been coated with
colorless varnish and dried, dipping the articles thus treated in a solution of coloring
matter (the "coloring bath"), and then freeing the dipped articles from superfluous
coloring solution, substantially as set forth.
2. A coloring bath for use in the process specified in the preceding claim,
consisting of a solution of vegetable aniline or alizarine colouring matters (free
from fat) in alcohols ethyl-acetate, amyl-acetate or acetone with or without the
addition of alkalies, substantially as set forth.
Dated this 10th day of November 1893.
JACQUES PERL,
Per J. G. L.