IMPROVEMENTS' IN THE TREATMENT OF THE TEXTILE FIBRES DYED BLACK OR GREY OR SHADES APPROACHING, WITH
Year: 1882

page_text: LETTERS PATENT to William Jules Samuel Grawitz of Fontenay-sous-Bois
in the department of the Seine, France, Civil Engineer for an Invention of
IMPROVEMENTS' IN THE TREATMENT OF THE TEXTILE FIBRES DYED BLACK
PROVISIONAL SPECIFICATION left by the said William Jules Samuel
Grawitz at the Office of the Commissioners of Patents on the 31st July'
1882
WILLIAM JULES SAMUEL GRAWITZ of Fontenay-sous-Bois in the department
of the Seine, France, Civil Engineer. IMPROVEMENTS IN THE TREATMENT OF
THE TEXTILE FIBRES DYED BLACK OR GREY OR SHADES APPROACHING, WITH
ANILINE
My Invention consists in treating textile materials dyed with aniline, black or
grey, or shades approaching black or grey, by means of non-alkaline reducing.
agents such as for example: sulphurous acid or other acids possessing reducing
properties, or the proto-salts of iron or other non alkaline metallic salts possessing;
reducing properties.
It is preferred to use these reducing agents in presence of a free acid.
After this treatment the textile materials are carefully washed before being
dried.
This treatment removes the bronze or violet tint or shade of aniline blacks and
greys. Moreover it modifies or partially dissolves the metallic oxides fixed on the
fibres in combination with the color
The textile materials are thus rendered well adapted to receive the usual chemical
treatment such as soaping, oiling &c or to be subjected to mechanical preparation
such as calendering, glossing &c

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Jules Samuel Grawitz in the Great Seal Patent Office on
the 29th January 1883.
WILLIAM JULES SAMUEL GRAWITZ of Fontenay-sous-Bois in the Department
of the Seine France Civil Engineer. "IMPROVEMENTS IN THE TREATMENT OF
THE TEXTILE FIBRES DYED BLACK OR GREY OR SHADES APPROACHING WITH
ANILINE."
My Invention consists in treating textile materials dyed with aniline, black or
grey or shades approaching black or grey, by means of non-alkaline reducing agents
such as for example, sulphurous acid or other. acids possessing reducing properties,
or the proto-salts of iron or other non-alkaline metallic salts possessing reducing
properties.
It is preferred to use these reducing agents in presence of a free acid.
After this treatment the textile materials are carefully washed before being
dried.
This treatment removes the bronze or violet tint or shade, of aniline blacks and
greys. Moreover it modifies or partially dissolves the metallic oxides fixed on the
fibres in combination with the color.
The textile materials are thus rendered well adapted to receive the usual chemical
treatment such as soaping oiling &c or to be subjected to mechanical preparation
such as calendering glossing &c.
Take for example 110 lbs of cotton dyed fast black with 11 lbs of aniline and the
proper quantity of bichromate of potash and acid. To about 200 gallons of water
I add half a gallon of bisulphite of soda at 30° Beaumé and half a gallon of
concentrated sulphuric acid. I immerse the 110 lbs of cotton in this bath for about
half an hour moving it about therein as usual in dyeing, after which I wash the
cotton in hot or cold water and dry it.
The greater the quantity of the reducing agent employed the more the nuance of
the black inclines to green.
4
The reaction is quicker and more energetic when effected with the aid of heat.
The quantity of the reducing agent to be employed depends upon the quantity
of aniline fixed on the fibres in dyeing.
Having described the nature of the said Invention and the manner of performing
the same I declare that what I claim is :-
The treatment of textile materials dyed aniline black or grey or shades
approaching black or grey, by means of non-alkaline reducing agents substantially
as herein specified.
In witness whereof I the said William Jules Samuel Grawitz have hereunto
set my hand and seal this twenty third day of January in the year of our
Lord One thousand eight hundred and eighty three.