The Production of Yellow Colour in or upon Silk by the Aid of Diazo-compounds or Nitrosamines.
Year: 1894

page_text: Date of Application, 10th Aug., 1894
Complete Specification Left, 16th Apr., 1895-Accepted, 18th May, 1895
PROVISIONAL SPECIFICATION.
The Production of Yellow Colour in or upon Silk by the Aid of
Diazo-compounds or Nitrosamines.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of London
Gentleman do hereby declare the nature of the said invention (which has been
communicated to me from abroad by The Badische Anilin & Soda Fabrik of
Ludwigshafen-on-Rhine in the Empire of Germany) to be as follows:-
This invention relates to the production of yellow colour in or upon silk by
suitably treating the silk with diazo-compounds or with nitrosamines. A chemical
combination appears to take place resulting in the conversion of the silk or some
constituent thereof into a coloured body. The colour of the silk so produced is in
many cases very fast against the action of light water and soap.
A large variety of diazo compounds can be used but I believe that those which
contain substituting nitro- or halogen-groups and the like will be found best in
practice and similarly that nitrosamines which contain such substituting groups will
be found best but at the same time the invention is not restricted to the use of
these diazo-compounds and nitrosamines as a large variety of both classes of bodies
can be used.
The production of the yellow silk can be effected by treating the silk with a cold
dilute solution of the diazo-compound or of the nitrosamine moving the silk
constantly in the liquid. Or the silk may be printed with a suitably thickened
solution of diazo-compound or of nitrosamine. The colour produced can be
discharged by reducing agents; further if the silk be printed with suitable
dyestuff components then on subsequently treating with the diazo-compounds or
nitrosamines besides the production of the yellow colour azo-dyes will be produced
simultaneously so that colours may be produced on a yellow ground. These
instances indicate the large variety of ways in which the invention can be used.
The diazo compounds are preferably used in the presence of sodium acetate, but
this is not invariably necessary; the nitrosamines can be used in the form of their
soluble salts, in some cases acetic acid or chloride of ammonia may advantageously
be added.
The following examples will serve to further illustrate the nature of the invention
but I do not confine myself to the details given.
The parts are by weight.
EXAMPLE 1.
Convert about one part by weight of the sodium salt of para nitro-phenyl-
nitrosamine into diazo compound and dilute the solution with water so that about
five thousand parts of solution result. To the solution add one part of sodium
acetate and then introduce about one hundred parts of silk previously soaked with
water, move the silk through and through the bath for about half an hour when the
colouration will be ended and the bath exhausted or nearly so. Wash, pass through
dilute acetic acid and dry. In order to prevent too rapid dyeing the silk may be
introduced before the addition of the sodium acetate to the bath and this may be
added gradually and in small quantities at a time during the operation.

page_text: If the dyeing operation be effected by the use of para-nitro-diazo-benzene-
chloride alone the operation proceeds slowly and the dye-bath is only exhausted
with difficulty.
By using the diazo-compound of sulphanilic acid in the presence of sodium
acetate the silk also becomes yellow, but the operation takes longer and it is
advantageous to use more concentrated baths; the baths are only exhausted very
slowly or incompletely.
EXAMPLE 2.
Dissolve one part of para di-chloro-phenyl-nitrosamine in about five thousand
If the dyeing operation be effected by the use of para-nitro-diazo-benzene-
chloride alone the operation proceeds slowly and the dye-bath is only exhausted
with difficulty.
By using the diazo-compound of sulphanilic acid in the presence of sodium
acetate the silk also becomes yellow, but the operation takes longer and it is
advantageous to use more concentrated baths; the baths are only exhausted very
slowly or incompletely.
EXAMPLE 2.
Dissolve one part of para di-chloro-phenyl-nitrosamine in about five thousand
parts of water and then introduce about one hundred parts of silk previously well
soaked with water. Move the silk through and through the bath till this is
exhausted. If it be desired to work quickly heat the bath to about fifty degrees
Centigrade.
Dated this 10th day of August 1894
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
The Production of Yellow Colour in or upon Silk by the Aid of
Diazo-compounds or Nitrosamines.
1, JAMES YATE JOHNSON, of 47 Lincoln's Inn Fields, in the County of
London, Gentleman, do hereby declare the nature of this invention (which has
been communicated to me from abroad by The Badische Anilin & Soda Fabrik,
of Ludwigshafen-on-Rhine, in the Empire of Germany) and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
The invention relates to the production of yellow colour in or upon silk by
suitably treating the silk with diazo-compounds or with nitrosamines. A chemical
combination appears to take place resulting in the conversion of the silk, or some'
constituent thereof, into a coloured body. The colour of the silk so produced is,
in many cases, very fast against the action of light, water and soap.
A large variety of diazo-compounds can be used, but I believe that those which
contain substituting nitro- or halogen-groups and the like will be found best in
practice, and similarly that nitrosamines which contain such substituting groups
will be found best but at the same time the invention is not restricted to the use of
these diazo-compounds and nitrosamines as a large variety of both classes of bodies
can be used.
The production of the yellow silk can be effected by treating the silk with a cold
dilute solution of the diazo-compound or of the nitrosamine, moving the silk
constantly in the liquid. Or the silk may be printed with a suitably thickened
solution of diazo-compound or of nitrosamine. The colour produced can be
discharged by reducing agents. Further if the silk be printed with suitable
dyestuff components then on subsequently treating with the diazo compounds or
nitrosamines besides the production of the yellow colour, azo dyes will be
produced simultaneously so that colours may be produced on a yellow ground.
These instances indicate the large variety of ways in which the invention can
be used.
The diazo compounds are preferably used in the presence of sodium acetate but
this is not invariably necessary. The nitrosamines can be used in the form of their
soluble salts. In some cases acetic acid or chloride of ammonia may advantageously
be added.

page_text: Slightly different shades of yellow are obtained by the use of different diazo-
compounds or nitrosamines, as is illustrated by the following table :-
The following examples will serve to further illustrate the nature of the
invention and the manner in which it can be carried into practical effect but I do
not confine myself to the details given. The parts are by weight.
EXAMPLE 1.
Convert about one part by weight of the sodium salt of para-nitro-phenyl-
nitrosamine into diazo-compound and dilute the solution with water so that about
five thousand parts of solution result. To the solution add one part of sodium
acetate and then introduce about one hundred parts of silk previously soaked with
water, move the silk through and through the bath for about half an hour when
the colouration will be completed and the bath exhausted, or nearly so. Wash,
pass through dilute acetic acid and dry. In order to prevent too rapid dyeing the
silk may be introduced before the addition of the sodium acetate to the bath and
this may be added gradually and in smail quantities at a time during the
operation.
If the dyeing operation be effected by the use of para-nitro-diazo-benzene-
chloride alone the operation proceeds slowly and the dye bath is only exhausted
with difficulty.
By using the diazo-compound of sulphanilic acid in the presence of sodium
acetate the silk also becomes yellow, but the operation takes longer and it is
advantageous to use more concentrated baths; the baths are only exhausted very
slowly or incompletely.

page_text: parts of water and then introduce about one hundred parts of silk previously well
soaked with water. Move the silk through and through the bath till this is
exhausted. If it be desired to work quickly heat the bath to about fifty degrees
Centigrade.
EXAMPLE 3.
Dissolve five parts of naphthyl-nitrosamine, as sodium salt, in about ten thousand
parts of water. To this add one hundred and twenty parts of dilute acetic acid
(containing one per cent. real acid C,H,O₂) or a similar quantity of a one per cent.
solution of ammonium chloride. Introduce about one hundred parts of silk and
move it through the bath for about a quarter of an hour, wash and brighten
the colour by passing a few times through a very dilute acid bath. The dye bath
is not exhausted.
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. The production of yellow colour in or upon silk by treating it with a solution
of diazo-compounds or nitrosamines of primary aromatic amido-compounds all
substantially as described.
2. The production of yellow colour in or upon silk according to the methods
hereinbefore described in the examples.
3. As a new article of manufacture, silk dyed yellow by combination therewith
of diazo compounds or nitrosamines of primary aromatic amnido compounds and
such as can be obtained substantially as hereinbefore described.
Dated this 16th day of April 1895.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.