A Method of Dyeing with Sulphur Dyestuffs.
Year: 1899

page_text: Date of Application, 8th Dec., 1899
Complete Specification Left, 7th Sept., 1900-Accepted, 10th Nov., 1900
PROVISIONAL SPECIFICATION.
A Method of Dyeing with Sulphur Dyestuffs.
I, OLIVER IMRAY, of Birkbeck_Bank Chambers, Southampton Buildings, in
the County of London, Chartered Patent Agent, do hereby declare the nature of
this invention (as communicated to me from abroad by Die Farbwerke vormals
Meister Lucius & Brüning, of Hoechst a/Main, in the Empire of Germany,
Chemical Manufacturers) to be as follows:-
Sulphur dyestuffs obtained by heating various organic substances with sulphur,
with, or without sulphides of alkali metals are now of great and increasing
importance in the dye industry.
The process now generally adopted in dyeing with dyestuffs of this class,
consists in preparing the bath with the sulphur dye, common salt, sodium car-
bonate and a sulphide of an alkali metal, the dyeing taking place at nearly
boiling point, the material being kept as much as possible below the surface of
the bath.
This mode of working, however, has great drawbacks and requires scrupulous
attention. For, if the goods be exposed to the air, even for a comparatively short
time, uneveness will ensue by the dyestuff separating out on the parts exposed
to the air and thus spots are produced which cannot be removed.
The reason why sulphur colours produce uneven and spotted dyes is found by
my foreign correspondents to be the following:-
Sodium sulphide, which the dyestuff either contains when manufactured or
which is added to the bath on dissolving the dyestuff, has a reducing influence
besides a dissolving action on the dyestuff. Besides the dissolved dyestuff the
bath contains also the dyestuff reduced to the leuco-compound. Both appear to
possess different great affinities for the fibre and as the leuco-compound readily
oxidises in contact with the oxygen of the air at ordinary temperature,
an opportunity is given by the present mode of dyeing for producing uneveness
and spots by the dyestuff separating out on the material near the boiling point
when exposed to air, which on further working in the dyebath cannot be removed
or only incompletely, there being no excess of reducing agents in the bath.
Relying on these observations, my foreign correspondents have found that
very good results may be obtained in dyeing with sulphur dyes by transforming
them completely into their leuco-compounds, dyeing with them in this form and
finally transforming the leuco-compounds into the dyestuff by oxidation by the
air or other oxidising agents, in fact by dyeing the dyestuffs according to the
indigo-vat dyeing process.
The hydrosulphite-vat is best suited for reduction, whilst the sulphate of
iron-lime- or zincdust- lime-vat gives worse results to be accounted for by the
formation of compounds soluble with difficulty of the metallic salts and the leuco-
compounds of sulphur dyes. The raw melts are best not employed for reduction,
but the dye-acids obtained by oxidising or acidifying the dissolved raw melts.

page_text: The preparation of the vat and the dyeing therein is in general the same as
with indigo, only the additional excess of lime is generally not required as
when dissolving indigo-white. The leuco-compounds possess great affinity for
the fibre; they dye rapidly and evenly, whilst cold rinsing will hardly, if at
all, remove them from the fibre. The turning green" of the shade begins
immediately in an exceedingly even manner on the goods being taken out of
the bath and rinsed. The formation of the dyestuff being completed by exposure
to the air, the shades may be transformed into thorough fast tints by subsequent
treatment with metallic salts or other oxidising agents, as is done after dyeing
in a bath containing sulphides of alkali metals.
As with the indigo-vat, the same material may be introduced several times,
the colours becoming stronger and deeper by giving two or more ends. The re-
markable fact here is, that the shades treated with oxidising agents, such as sulphate
of copper, after the first immersion, yield on a second and subsequent immersion
disproportionately stronger and more powerful colours than when merely exposed
to the air.
The method described is of particular importance, as the reduction of the
sulphur dyes may be combined with the vat-dyeing of indigo, it thus being
possible to obtain in one vat with the recognised fast sulphur dyes and indigo,
shades just as fast, yet essentially cheaper, than those obtained with indigo
alone and also faster shades, than those of indigo which are topped with
other colours.
For dyeing in the vat the most suitable are the dyestuffs known as immedial-
blue C, immedial-black G and V extra (Cassella), katigen-blue (Bayer), noir
vidal (St. Denis), Clayton-fast-black D and other sulphur dyestuffs.
EXAMPLE.
4 kilos. of the dyestuff obtained according to our Patent Application No. 24538
of 1898 are treated with 60 litres of hydrosulphite solution of 13° Bé. specific
gravity at 50-60° C., till the colour of the solution becomes brown yellow.
The leuco-compound thus obtained is then poured into the vat containing about
2,000 litres of cold water.
The mode of working this vat depends upon the nature of the material to be
dyed and is carried out according as loose material, yarns, stuffs, cops cta.
are employed, in a similar manner as with indigo.
Dated this 8th day of December 1899.
ABEL & IMRAY,
Agents for the Applicant.
A Method of Dyeing with Sulphur Dyestuffs.
I, OLIVER IMRAY, of Birkbeck Bank Chambers, Southampton Buildings, in
the County of London, Chartered Patent Agent, do hereby declare the nature of
this invention (as communicated to me from abroad by Die Farbwerke vormals
Meister Lucius & Brüning, of Hoechst a/Main, in the Empire of Germany,
Chemical Manufacturers) and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
Sulphur dyestuffs obtained by heating various organic substances with sulphur
with or without sulphides of alkali metals are now of great and increasing
importance in the dye industry.
The process now generally adopted in dyeing with dyestuffs. of this class,

page_text: onsists in preparing the bath with the sulphur dye, common salt, sodium car-
onate and a sulphiae of an alkali metal, the dyeing taking place at nearly
boiling point, the material being kept as much as possible below the surface of
he bath.
This mode of working, however, has great drawbacks and requires scrupulous
attention. For, if the goods be exposed to the air, even for a comparatively short
time, uneveness will ensue by the dyestuff separating out on the parts exposed
to the air and thus spots are produced which cannot be removed.
The reason why sulphur colours produce uneven and spotted dyes is found by
my foreign correspondents to be the following:
―
Sodium sulphide, which the dyestuff either contains when manufactured or
which is added to the bath on dissolving the dyestuff, has a reducing influence
besides a dissolving action on the dyestuff. Besides the dissolved dyestuff, the
bath contains also the dyestuff reduced to the leuco-compound. Both appear to
as the leuco-compound readily
possess great affinity for the fibre and
oxidises in contact with the oxygen of the air at ordinary temperature.
in the present mode of dyeing uneveness and spots are liable to be produced by
the dyestuff separating out on the material, when the bath is near the boiling
point, on exposure to air, and on further working in the dyebath these spots
cannot be removed or only incompletely, there being no excess of reducing agents
in the bath. As a result of these observations, my foreign correspondents have
found that very good results may be obtained in dyeing with sulphur dyes by
transforming them completely into their leuco-compounds, dyeing with them
in this form and finally transforming the leuco-compounds into the dyestuff by
oxidation by the air or other oxidising agents, in fact by dyeing with the dye-
stuffs in the manner of indigo-vat dyeing process.
The hydrosulphite-vat alone is well suited for reduction, whilst the sulphate of
iron and lime, or zinc-dust and lime-vat gives bad results. The crude products
obtained by the heating process in making the dyestuffs are best not employed for
reduction but the dye acids obtained by oxidising or acidifying the dissolved
crude product answer well..
*
The preparation of the vat and the dyeing therein is in general the same as
with indigo, only the addition of excess of lime is generally not required, as
when dissolving indigo-white. The leuco-compounds possess great affinity for
the fibre; they dye rapidly and evenly, whilst cold rinsing will hardly, if at
turning green" of the shade begins
all, remove them from the fibre. The
immediately in an exceedingly even manner on the goods being taken out of
the bath and rinsed. The formation of the dyestuff being completed by exposure
to the air, the shades may be transformed into thoroughly fast tints by subsequent
treatment with metallic salts or other oxidising agents, as is done after dyeing
in a bath containing sulphides of alkali metals.
As with the indigo-vat, the same material may be introduced several times,
the colours becoming stronger and deeper by giving two or more immersions. It is
remarkable that the shades treated with oxidising agents, such as sulphate
5 of copper, after the first immersion, yield on a second and subsequent immersion
disproportionately stronger and more powerful colours than when merely exposed
to the air.
The method described is of particular importance, as the reduction of the
sulphur dyes may be combined with the vat-dyeing of indigo, it thus being
possible to obtain in one vat with the recognised fast sulphur dyes and indigo,
shades just as fast, yet essentially cheaper. than those obtained with indigo
alone and also faster shades, than those of indigo topped with other colours.
For dyeing in the vat, the most suitable are the dyestuffs known as immedial-
blue C; the dyestuffs obtained according to Specification No. 24538 of 1898;
55 the dyestuffs obtained by heating with sulphur and sodium sulphide in an aqueous
solution para-amidophenol, para-amidophenolcarboxylic acid, para-amidophenol-
sulphonic acid, the condensation products of dinitrochlorobenzene with para-amido-

page_text: Immedial-black G and V extra (Cassella); katigen-blue (Bayer); noir vidal
(St. Denis); Clayton-fast-black D and other sulphur dyestuffs.
EXAMPLE.
4 kilos. of the dyestuff obtained according to our Patent Application No. 24538
of 1898 are treated with 60 litres of hydrosulphite solution of 13° Bé. specific
gravity at 50-60° C., till the colour of the liquid becomes brown yellow.
The solution of leuco-compound thus obtained is then poured into the vat
containing about 2,000 litres of cold water.
The mode of working this vat depends upon the nature of the material to be
dyed and is carried out accordingly, as loose material, yarns, stuffs, cops, etc.,
are employed, in a similar manner with indigo.
Having now particularly described and ascertained the nature of my. said
invention and in what manner the same is to be performed, I declare that what
I claim is:
The herein described method of dyeing with sulphur dyestuffs, after the
manner employed in the indigo-vat dyeing process, by first transforming them by
hydrosulphites into their leuco-compounds, then dyeing with them in this form
and finally developing the dyestuff by oxidation.
Dated this 7th day of September 1900.
ABEL & IMRAY,
Agents for the Applicant.