An Improvement or Improvements in White and Colour Discharge, or Enlevage Printing of Dyed Paranitraniline Red and Related Substances.
Year: 1897

page_text: Date of Application, 27th May., 1897-Accepted, 23rd Oct.,
1897
COMPLETE SPECIFICATION.
An Improvement or Improvements in White and Colour Discharge,
or Enlevage Printing of Dyed Paranitraniline Red and Related
Substances.
We, Dr. HENRY ZUBLIN, and Dr. ADOLPHUS ZINGG, both of Fratte di Salerno, Italy,
Chemists, 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 :-
The known process (invented by the Farbwerke, vormals Meister Lucius &
Brüning of Hoechst a/M) for white and colured discharge or enlevage printing on
dyed para-nitraniline red, by means of tin salt with an addition of glycerine, acetine
and similar substances, has the disadvantage that a pure white cannot be produced
without corroding the fibre, and further that such coloured prints have only a very
moderate degree of fastness.
By our process these two drawbacks are entirely removed.
The new process is based on the observation that finished dyed para-nitraniline and
other azo-colouring matters which are produced directly upon the fibre, are reduced by
glucose or other kinds of sugar in an alkaline solution in the presence of alcohol,
phenol, naphthol, glycerine or analogous substances.
Now our process differs from the well known alkaline discharge or enlevage
printing process upon Turkey red (according to which the alumina-alizarine lake is
split up into its constituents by the strong lye, and the glucose enters in the process
only when indigo colour is printed on at the same time) essentially in the fact, that
according to the new process the colouring matter undergoes an alkaline reduction on
the fibre.
The mode of operation which we employ as follows:
The bleached and dried material or fabric (which is impregnated with ẞ-naphthol-
sodium, for instance for dyeing red) is passed through diazo-para-nitraniline, washed,
and if necessary, soaped, dried, impregnated on one or on both sides with glucose or
other kinds of sugar, again dried and then printed, with a strongly alkaline discharging
or enlevage-colour which contains, in addition to glucose and glycerine or similar
bodies of the ihydrooxyd group (OH) as Naphthol, Phenol, alcohol, etc., a thickening
agent such as gum, British gum, tragacanth &c. After the printing and drying
operations, the fabric is steamed for a short time, passed through acids, well washed,
and soaped.
When printing with colours containing a great deal of sugar, such as can be used
in "perrotine printing," that is to say in other words, when printing styles which
allow using an abundance of colour, the previous sugaring of the fabric may be
omitted.
Besides white, which is obtained by printing the above named discharging
composition, blue, yellow, green or black can be simultaneously printed by mixing to
he discharging composition, Indigo and caustic alkali for blue, leadoxyd of soda for
yellow, a mixture of the two last for green and steam aniline black for black.
printed goods are dried, steamed, passed through acid, soap, chromate and finished.
The obtained colours are quite fast and the fibres will keep their original strength.
The

page_text: Some proportions of the Agents used for Enlevage Printing of dyed Paranitraniline
red and related substances are as follows:-
Strength of Glucose solution, used for impregnating the paranitraniline dyed cloth
16® Bé. = 25° Tw.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
The improvement in the white and colour-discharge or enlevage-printing of
finished dyed para-nitraniline red and similar azo-colouring matters or dyes produced
direct on the fibre as above described, characterized by the fact that these coloring
matters or dyes are reduced by alkaline process without injury to the vegetable fibre,
and can be completely discharged or imprinted upon with entirely fast discharge
colours.
COT
LUTIT TO Cun
IT AT
BREWER & SON,
London and Leeds, Agents for the Applicants.