Improvements relating to Compounds suitable as Protective Coatings or Paints for Iron and Steel.
Year: 1892

page_text: Date of Application, 11th July, 1892-Accepted, 21st Jan., 1893
COMPLETE SPECIFICATION.
Improvements relating to Compounds suitable as Protective Coatings
or Paints for Iron and Steel.
I, PAUL LEHMANN, Managing Director of the Actiengesellschaft für
Asphaltirung und Dachbedeckung, formerly Johannes Jeserich, of Wassergasse
No. 18, Berlin, Germany, do hereby declare the nature of this inyention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
If parts of iron are being coated with oil paint or lacquer, in the usual manner,
the paint covers indeed the surfaces, but it does not penetrate into the pores of
the iron, owing to the semi-fluid consistency or viscosity of these materials;
consequently, if the pores contain some moisture, or if the layer of rust is very
thick, the protecting coat of paint peels off, or beneath it the formation of rust
proceeds.
The present invention relates to a new or improved material called "Siderosthen,"
which not only possesses in a high degree the qualities of a good paint, but also
obviates the inconveniences mentioned above.
Siderosthen is produced from the tar obtained from gas works producing fat gas,
by adding to the tar a suitable quantity of "goudron," or it consists of the fat gas
tar mixed with sulphur.
per cent.
With goudron" I wish to designate a product consisting of about 85
of purified Trinidad asphalte (Trinidad épuré) and about 15 per cent. of refined
asphalte oil, (see also Karmarsch & Heeren's Technical Dictionary III. edition,
vol. ix., fol. 51, 2, and Dietrich's Kunststrassenbaus).
With "fat gas
of coal.
"
I wish to designate gas produced from oil or animal fat, instead
Chemical analysis of the pure fat gas tar has shown, that the same contains:
2,265 per cent. of ingredients (water and benzene) boiling at
It follows, that the said tar contains relatively small quantities of volatile
hydrocarbons, but considerably more hydrocarbons boiling at a high temperature
and therefore difficult to evaporate.
These two constituents (high boiling and low boiling hydrocarbons) are free
from sulphur or chemical combinations of the same and are of viscous consistency.
The greatest part of the said tar (about 50 per cent.) consists of a mass, which is
viscous when heated, and stiff, asphalte-like at ordinary temperatures, and which
contains perceptible quantities of sulphur in chemical combination. In the above
analytical table, this part is shortly designated as asphalte."
«
To this fat gas tar I add a suitable quantity of "goudron," until the product is
composed of the following ingredients

page_text: I thus obtain a mass richer in hydrocarbons boiling at a high temperature and
poor in hydrocarbons boiling at a low temperature, which property renders it
suitable and useful for painting parts of iron, as it consists throughout of hydro-
carbons which will not easily decompose and therefore offer great resistance to
external influences.
Besides the mixture described above, numerous experiences have shown, that we
may obtain also extremely advantageous results by mixing the fat gas tar with 5
to 8 per cent. of sulphur, instead of "goudron," so as to produce an oil varying in
its composition similarly as the mixture of goudron and fat gas tar, but said product
is much more suitable for the painting of iron parts.
If fat
gas
tar is heated to a high temperature, and sulphur is added, the latter
dissolves in the tar. During the further heating a double result is effected. At
first, the hydrocarbons are sulphureted and then they are deprived of a part of
their hydrogen, so that they become comparatively richer in carbon.
Siderosthen is, for the reasons explained above, quite indifferent against the
atmosphere, water and the like, and owing to its contents in fat gas tar, it penetrates
into the iron, loosens the rust and envelopes the ingredients of the paint in such a
manner that the same have no noxious effects on the iron. Besides, the paint
remains elastic, and does not come off in case of expansion, and is not liable to
crack, which would promote a new formation of rust, a very important feature for
the construction of iron bridges.
The production or process of manufacture of the improved mass is as follows:
The fat gas tar is freed of water, as much as possible, by pouring off the water
which floats on the surface owing to its smaller specific gravity; subsequently the
tar is heated in vessels of cast iron, and when it has attained a temperature of
about 100° C., either 10 per cent. of its weight of "goudron," or 5 to 8 per cent. of
sulphur is added, then the mass is heated, to promote the mixture or dissolution,
about another quarter of an hour. In such a manner, the tar is at first freed of
water, subsequently carbureted and sulphureted.
The product resulting from this process is now ready for painting and may be
used immediately. If this is not possible, it is allowed to cool and re-heated when
it is to be used for painting.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. A material suitable as a protective coating or paint for iron and steel, said
material consisting of tar produced by fat gas works, and "goudron" in the propor-
tions substantially as described.
2. A material suitable as a protective coating or paint for iron and steel, said
material consisting of tar produced by fat gas works and sulphur in the proportions
substantially as described.
3. The manufacture of compounds suitable as protective coatings or paints from
certain kinds of tar and "goudron or sulphur, in the manner substantially as
described.
"
Dated this 11th day of July 1892.
PAUL LEHMANN,
By Fairfax & Wetter,
433, Strand, London, Agents.
PAUL LEHMANN,
By Fairfax & Wetter,
433, Strand, London, Agents.