Improvements in Treating Paranitraniline Røds and Analogous Colors when applied on Vegetable Fibres or Silk, to Render them Fast to Light.
Year: 1897

page_text: Date of Application, 30th June, 1897
Complete Specification Left, 30th Mar., 1898-Accepted, 18th June, 1898
Improvements in Treating Paranitraniline Røds and Analogous
Colors when applied on Vegetable Fibres or Silk, to Render them
Fast to Light.
I, HORACE KOECHLIN, of 17, Avenue du Mont Riboudet, Rouen, France, Chemist,
do hereby declare the nature of this invention to be as follows:-
Paranitraniline red and the reds obtained with nitrosamine.or azophore &c. offer
only a poor resistance to light. An exposure of some days to the sun suffices to
attack the shade, which at once fades very quickly and soon completely disappears.
I have discovered a method of rendering these reds very fast to light, while at
the same time increasing the beauty and the brilliancy of the shade.
For this purpose, after having fixed the reds by the ordinary known processes,
upon vegetable fibres in the form of either skeins, or wound on bobbins, or in the
piece, I pass these into a boiling, or it may be a cold, bath of dilute nitric acid alone
or to which has been added an oxidant-in the form of a metallic salt such as a
bichromate, or a copper salt; or I may first submit the fibres to the nitric acid bath
and then submit them to the bichromate or to a solution of an acetate of an alkaline
earth.
Acids other than nitric acid either do not act at all or only increase the resistance
of the red to a relatively small degree.
In carrying out my invention, I proceed for example as follows:-I take a solution
of nitric acid containing 5 cubic centimetres of acid per litre, and into this boiling
solution I pass for some minutes the dyed red fibre. then wash. The red becomes
brighter and absolutely fixed to light; the fibre is in no way changed and undergoes
no shrinkage.
By the addition of 5 grammes of an alkaline bi-chromate per litre of dilute
nitric acid and passing the red into the boiling mixture the shade becomes still
more fixed to light.
The addition of a copper salt in small quantity does not turn the red brownish,
as occurs when these salts are employed alone, and its fastness is increased.
It will be understood that instead of working at the boiling point, my invention may
be carried out in the cold, but in this case it will be necessary to use more con-
centrated acid and to lengthen the duration of immersion. For instance, I may
then employ a bath containing 100 to 200 cubic centimetres of nitric acid per litre,
and keep the lyed fibre for 1 hour in this solution at a temperature of 15° C.
A yet superior result is attained if, after the treatment with nitric acid, cold or
hot, the dyed fibre is kept for some minutes in a boiling solution of acetate of lime
or of magnesia containing for example 100 cubic centimetres per litre. The passage
through the nitric acid may also be repeated twice or thrice.
I have further found that if the red is submitted to a treatment in B-naphthol
alone or with an addition of soap, before passing it into the nitric acid bath, or
after treatment in the nitric acid bath, the final result is better.

page_text: Or the red may with advantage be submitted to a soap bath containing about 20
grammes of soap per litre of water before or after treatment in the nitric acid
bath.
To render the red more bluish in shade I may, either before or after the treatment
with acid, pass the dyed fibres into concentrated caustic soda solution, hot or cold,
containing glycerine to prevent mercerizing; for example I take 250 cc. glycerine
per litre of caustic soda of 30° Bé.
I wish it to be well understood that the times and quantities indicated above as
examples may be modified within certain limits according to the goods to be
treated.
3'
I
Also the red which is to be rendered fast may be applied on the fibre either by
dyeing, printing or in any other way.
Improvements in Treating Paranitraniline Reds and Analogous
Colors when applied on Vegetable Fibres or Silk, to Render them
Fast to Light.
I; CECILE KOECIILIN, of 17, Avenue du Mont Riboudet, Rouen, France, Widow
and Administratrix of Horace Kocchlin, deceased, late of the same address, Chemist,
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:
Paranitraniline red and the coloring matters which are obtained with nitrosamine,
azophore or other products containing paranitraniline in whatever form it may be,
possess only an indifferent fastness to light. When such colours have been exposed
for some days to sunlight their shade is seriously affected, and this alteration rapidly
proceeds, and even leads to complete destruction of the color.
!
Now the present invention has for object a method of rendering such red dyes
exceedingly fast to light, while at the same time increasing the beauty and brilliancy
of their shade.
་
With this object the spun fibre (in the form of hanks or spools) or in the piece;"
after the red lias been fixed thereon in the known manner, is led through boiling
or cold dilute nitric acid, which may either be employed alone or may contain a
suitable oxidant such as a metallic salt, for example a bichromate or a salt. of
copper, or the dyed fibre may be immersed first in a bath of nitric acid and then in
a bichromate bath or a solution of an acetate of an alkaline earth:
Acids other than nitric acid either do not act at all, or increase the resistance of
the red dye to a very small extent.
:
The following example will serve to more closely indicate how this invention can
be carried into effect.
.
The dyed fibre is steeped for some minutes in a boiling solution containing 5 ccm.
nitric acid per litre, and then washed. The red becomes much more brilliant and is
completely fast to light. The fibre is quite unattacked and suffers no contraction
or 'slirinkage.
"
1
If bichromate of an alkali be added to the nitric acid in the proportion of 5 'gr.
per litre, and the dyed fibre be steeped in this boiling bath, the color. is rendered
still more fast to light.
F

page_text: The addition to the dilute nitric acid of a small proportion of a copper salt does
not turn the red brownish, which would occur if these salts were employed alone;
the fastness is moreover increased.
Instead of operating at a boiling temperature the method may be carried out in
5 the cold; in this case, however, it is necessary to employ a more concentrated acid,
and the duration of steeping must be increased. For example in this case
100-200 ccm. nitric acid per litre would be taken and the dyed fibre kept in this
solution for an hour at 150 C.
A still better result may be attained if after the hot or cold treatment with nitric
acid the dyed fibre be immersed for some minutes in a boiling solution of acetate
of lime or of magnesium (containing for example 100 ccm. of the commercial product
per litre of water). The treatment with nitric acid may also be repeated two or
three times.
Finally it has been discovered that the result is still better when the dyed fibre
is treated with betanapthol (under the conditions in which this body is ordinarily
employed to produce azo colors directly on fibre) alone or with the addition of soap,
before being submitted to the action of the nitric acid bath, or after treatment
therein.
Or the red may with advantage be submitted to a soap bath containing about
20 gr. of soap per litre of water before or after treatment in the nitric acid bath.
In order to render the red of a bluer shade the fibre may be steeped, before or
after the acid treatment, in a hot or cold concentrated soda lye to which glycerine
has been added to prevent mercerisation; there are employed for example 1 litre
soda lye of 30° Beaumé and 250 ccm. glycerine.
It is to be well understood that the times and proportions above given only serve
as examples, and can be varied within certain limits according to the goods to bo
treated. Further, the red may be produced upon the fibre by dyeing or printing
or in any other manner.
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
in respect of the treatment of colors of the kind hereinbefore referred to when
applied on vegetable fibres or silk is:—
1. The method or process which consists in submitting the fibre after the color has
been fixed thereon, to a bath of dilute nitric acid, substantially as and for tho
purpose hereinbefore described.
2. The method or process which consists in submitting the fibre after the color
has been fixed thereon, to a bath of dilute nitric acid containing a suitable oxidant
preferably an alkaline bichromate, substantially as and for the purpose hereinbefore
described.
3. The method or process which consists in submitting the fibre after the color
has been fixed thereon, first to a bath of dilute nitric acid and then to a bath con-
taining a suitable oxidant, preferably an alkaline bicliromate, substantially as and
for the purpose hereinbefore described.
4. The method or process which consists in submitting the fibre after the color
has been fixed thereon, first to a bath of dilute nitric acid and then to a boiling
solution of acetate of an alkaline earth, substantially as and for the purpose set
forth.
5. The method or process which consists in submitting the fibre after the color has
been fixed thereon, and before or after treatment in a bath of dilute nitric acid as
described, to treatment with beta-napthol, alone or with the addition of soap,
substantially as and for the purpose set forth.
6. The method or process which consists in submitting the fibre after the color
has been fixed thereon and before or after treatment in a bath of dilute nitric acid
as described; to a soap bath, substantially as set forth.
7. The method or process which consists in submitting the fibre after the color
has been fixed thereon and before or after treatment in a bath of dilute nitric acid

page_text: as described, to a concentrated soda lye containing glycerine, substantially as and
for the purposes set forth.
Dated this 30th day of March 1898.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.