Process for the Partial or Total Destruction of Beta Naphthol on the Fibre by Oxidation by Means of Persulphates.
Year: 1895

page_text: Date of Application, 22nd June, 1895
Complete Specification Left, 21st Mar., 1896-Accepted, 25th Apr., 1896
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE FARBWERKE, vormals MEISTER LUCIUS
AND BRUNING, of Hoechst a Main, in the Empire of Germany, Chemical
Manufacturers.]
Process for the Partial or Total Destruction of Beta Naphthol on
the Fibre by Oxidation by Means of Persulphates.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, do hereby declare the nature of this
invention to be as follows:-
The production of insoluble naphthol azo colouring matters on cotton fibre has
attained some extent and importance not only by the discovery of a whole series of
very suitable amido bases, but also by the institution of simple and suitable dyeing
and printing processes, which facilitate the combination of these colouring matters
with each other and the production of discharge and reserve articles.
While suitable methods exist for producing white discharge or reserve effects
with the naphthol azo-colouring matters, the production of coloured discharge
reserves (for instance blue, yellow, green &c. on red or blue grounds) have hitherto
not lead to any perfectly satisfying result.
The use of discharge colours which, when printed on the goods impregnated
with naphthol sodium, contain tannin or albumen body colours mixed with suitable
tin compounds, gives colours that are neither soap- nor light-proof, as a fixing
thereof by steaming before the following dyeing in the diazo solution could not be
effected. As the use of steam colours appears to be excluded, the only possible
and logically correct process appears to be that which also allows the discharge
colours to be produced as naphthol azo colours upon the fibre.
This is based upon two possibilities:
1. The diazo compound of the imprinted colour completely saturates at the
printed portions the entire quantity of the naphthol, so that at the following
dyeing of the ground there will no longer exist at those places any excess of
naphthol.
2. At the printed places the excess of naphthol is deprived of its property of
farther coupling when dyeing in the diazo solution.
In the first case, I have a saturation process, in the second case an actual
discharge process.
The first is little suitable for practical working, as it only succeeds with difficulty
to impress in each separate case just so much of the diazo compound as is required
by the naphthol sodium preparation, which is often very concentrated, and this
process appears to be only suited for dark discharge colours, and not for middle
and light colours.
The second process requires the use of a substance that can be added to the diazo
printing colour without damaging it, and only acts on the excess of naphthol that
is to say, destroys it, after the coupling of the diazo compound.
My correspondents have discovered in the persulphates a means which when added
to the diazo printing colour, does not detrimentally affect the diazo-compound, and,
after printing, converts the remaining excess of naphthol by oxidation into a
compound that is no longer capable of coupling.
As is known, the persulphates are well preservable in acid solution and they
exercise a strong oxidising action on phenol-like compounds in neutral or alkaline
condition. If cotton fabric impregnated with alkaline naphthol-sodium solution is

page_text: printed upon with slightly acetic thickened persulphate solutions, the naphthol will
be converted under heating, at the parts printed upon into a substance that is no
longer capable of coupling. If now the fabric be afterwards dyed in a diazo-
solution, there will result, according to the concentration of the persulphate
discharge colour employed, lighter shades, up to nearly colourless ones.
This reaction of persulphate upon naphthol, first observed by my correspondents,
can be employed in various ways in discharge-printing with naphthol azo colouring
matters.
For example, to produce blue patterns on a red ground in imitation of the
perfect Schlieper-Baum article-indigo blue printed in discharge upon turkey
red, which it is so difficult to obtain, there is printed on white cotton fabric padded
with naphthol sodium, a printing colour, containing ammonium persulphate and
composed of diazotised dianisidin, and a suitable copper compound; after drying,
the fabric is dyed in a diazo solution prepared from paranitranilin.
In carrying out the invention my correspondents have observed that the certain
metallic salts for instance tetrachloride of tin, exercise a favorable influence in the
oxidation of the ẞ naphthol by means of persulphate; they are best added to the
persulphate diazo printing colour. In order furthermore to obviate the detrimental
action of the copper salt of the dianisidin printing colour on the dyed nitranilin red,
there is added oxalate of ammonia, both to the diazo dye bath of p. nitraniline, and
in the following soap bath.
Example. The white bleached cotton fabric is impregnated with the naphthol
grounding; after drying it is printed with the blue discharge colour, dried, passed
through the developing bath, washed, and soaped with addition of oxalate of
ammonia.
NAPHTHOL ROUNDING.
200 grammes
Beta naphthol
Soda lye 22° Bé.
Recinolate of ammonia
Traganth water +880
Acetate of soda crystals
320 cube cm.
-
600 gr.
1000 gr.
250 gr.
dissolved
in 10 litres.

page_text: Process for the Partial or Total Destruction of Beta Naphthol on
the Fibre by Oxidation by Means of Persulphates.
I, OLIVER IMRAY, of No. 28 Southampton Buildings, Chancery Lane, in the
County of London, Chartered Patent Agent, 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 production of insoluble naphthol azo colouring matters on cotton fibre has
attained some extent and importance not only by the discovery of a whole series of
very suitable amido bases, but also by the institution of simple and suitable dyeing
and printing processes, which facilitate the combination of these colouring matters
with each other and the production of discharge and reserve articles.
While suitable methods exist for producing white discharge or reserve effects
with the naphthol azo colouring matters, the production of coloured discharge
reserves (for instance, blue, yellow, green, &c. on red or blue grounds) have
hitherto not led to any perfectly satisfying result. The use of discharge colours
which, when printed on the goods impregnated with naphthol sodium, contain
tannin or albumen body colours mixed with suitable tin compounds, gives colours
that are neither soap nor light proof, as a fixing thereof by steaming before the
following dyeing in the diazo solution could not be effected. As the use of steam
colours appears to be excluded, the only possible and logically correct process
appears to be that which also allows the discharge colours to be produced as
naphthol azo colours upon the fibre.
This is based upon two possibilities :
1. The diazo compound of the imprinted colour completely saturates at the
printed portions the entire quantity of the naphthol, so that at the following dyeing
of the ground there will no longer exist at those places any excess of naphthol.
2. At the printed places the excess of naphthol is deprived of its property of
farther coupling when dyeing in the diazo solution.
In the first case,
discharge process.
I have a saturation process, in the second case an actual
The first is little suitable for practical working, as it only succeeds with
difficulty to impress in each separate case just so much of the diazo compound as is
required by the naphthol sodium preparation, which is often very concentrated, and
this process appears to be only suited for dark discharge colours, and not for
middle and light colours.
The second process requires the use of a substance 'that can be added to the
diazo printing colour without damaging it, and only acts on the excess of naphthol
that is to say destroys it, after the coupling of the diazo compound.
My correspondents have discovered in the persulphates a means which when
added to the diazo. printing colour, does not detrimentally affect the diazo
compound, and, after printing, converts the remaining excess of naphthol by
oxidation into a compound that is no longer capable of coupling.
As is known, the persulphates are well preservable in acid solution and they
exercise a strong oxidising action on phenol-like compounds in neutral or alkaline
condition.
If cotton fabric impregnated with alkaline naphthol-sodium solution is
printed upon with slightly acetic thickened persulphate solutions, the naphthol
will be converted under heating, at the parts printed upon into a substance that is
no longer capable of coupling. If now the fabric be afterwards dyed in a diazo-
solution, there will result, according to the concentration of the persulphate
discharge colour employed, lighter shades, up to nearly colourless ones.

page_text: This reaction of persulphate upon naphthol, first observed by my correspondents
can be employed in various ways in discharge-printing with naphthol azo colouring
matters.
For example, to produce blue patterns on a red ground in imitation of the
perfect Schlieper-Baum article-indigo blue printed in discharge upon turkey red,
which it is so difficult to obtain, there is printed on white cotton fabric padded
with naphthol sodium, a printing colour, containing ammonium persulphate and
composed of diazotised dianisidine, and a suitable copper compound; after drying,
the fabric is dyed in a diazo solution prepared from paranitranilin.
In carrying out the invention my correspondents have observed that the certain
metallic salts for instance tetrachloride of tin, exercise a favorable influence in the
oxidation of the ẞ naphthol by means of persulphate; they are best added to the
persulphate diazo printing colour. In order furthermore to obviate the detrimental
action of the copper salt of the dianisidine printing colour on the dyed nitranilin
red, there is added oxalate of ammonia, both to the diazo dye bath of p. nitraniline
and in the following soap bath.
Example. The white bleached cotton fabric is impregnated with the naphthol
grounding; after drying it is printed with the blue discharge colour, dried, passed
through the developing bath, washed, and soaped with addition of oxalate of
ammonia.
HOCADING.
200 grammes
320 cube cm.
-
->
600 gr.
-
1000 gr.
-
250 gr.
dissolved in
10 litres.
Beta naphthol
Soda lye 22° Bé.
-
-
Recinolate of ammonia
Traganth water 1880
Acetate of soda crystals -

page_text: usual manuer with naphthol sodium, with persulphates, either alone or in
combination with diazo or tetrazo compounds with or without addition of metallic
salts, substantially as described.
Dated this 21st day of March 1906
ABEL & IMRAY,
Agents for the Applicant.