Improvements in Dyeing Black with Logwood.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Dyeing Black with Logwood.
I, GEORGE WILLIAM JOHNSON, of 47, Lincoln's Inn Fields, in the County of
London, Patent Agent, do hereby declare the nature of this invention (which
has been communicated to me from abroad by Kalle & Co., of Biebrich-on-Rhine,
in the German Empire) to be as follows:-
The object of this invention is to provide in place of the complicated process
or means hitherto used for the production of black on textile fibres by means of
logwood, a process or means by which very fine black shades are obtained by
means of logwood in the simplest manner. The invention is principally applic-
able to vegetable fibres, although it can be employed for animal fibres. It consists
in printing the fabric with a mixture of logwood-extract (haemateine) an iron
salt, and an organic acid, and treating the fibre thus prepared with a neutral
nitrite solution. This treatment with nitrite may for example be effected by
passing the material through a nitrite-bath, or by printing with nitrite, or the
fabric previously padded with nitrite may be printed with the aforesaid mixture.
The organic acid in the said mixture may be omitted or be replaced by an acid
salt, for instance bisulphate of soda.
The said process can be combined with other processes for the production of
dyestuffs on the fibre and multi-coloured effects be obtained.
The process is illustrated by the following examples but the invention is not
limited thereto

page_text: Improvements in Dyeing Black with Logwood.
I, GEORGE WILLIAM JOHNSON, of 47, Lincoln's Inn Fields, in the County of
London, Chartered Patent Agent, do hereby declare the nature of this invention
(which has been communicated to me from abroad by Kalle & Co., of Biebrich-on-
Rhine, in the German Empire) and in what manner the same is to be performed to
be particularly described and ascertained in and by the following statement:-
The object of this invention is to provide in place of the complicated process
or means hitherto used for the production of black on textile fibres by means of
logwood, a process, or means, by which very fine black shades are obtained by
means of logwood in the simplest manner.
The invention is principally applicable to vegetable fibres, although it can be
employed for animal fibres. It consists in printing the fabric with a mixture
of logwood-extract, (haemateine), an iron salt, and an organic acid, and treating
the fibre thus prepared with a neutral nitrite-solution. This treatment with
nitrite may for example be effected by passing the material through a nitrite-bath;
or by printing with nitrite, or the fabric previously padded with nitrite may be
printed with the aforesaid mixture. The organic acid in the said mixture may
be omitted or be replaced by an acid salt. for instance bisulphate of soda.
The said process can be combined with other processes for the production of
dyestuffs on the fibre and multi-coloured effects be obtained.
The process is illustrated by the following examples but the invention is not
limited thereto
EXAMPLE I.
The fabric is printed with a mixture of
110 gr. Haematcine
70
14
"
وو
Copperas
Tartaric acid
446 British gum
"
360
Water
99
and overprinted with
150 gr. Nitrite
290 British gum
560
"

page_text: may be reversed first padding the fabric with nitrite, and then overprinting
with a mixture of haemateine, mordant and acid.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.