An Improved Mordanting Agent and Process for Vegetable Fibres.
Year: 1896

page_text: Date of Application, 10th Oct., 1896
Complete Specification Left, 29th May, 1897-Accepted, 10th July, 1897
PROVISIONAL SPECIFICATION.
An Improved Mordanting Agent and Process for Vegetable Fibres.
-
J. ALEXANDER MELVILLE CLARK of the Firm of A. M. & Wm. Clark of 58
Chancery Lane in the County of Middlesex, Fellow of the Chartered Institute of
Patent Agents: do hereby declare the nature of this Invention (a communication
to me by the Firm of C. H. Boehringer Sohn of the Chemical Works, Niederingel-
heim-on-the-Rhine, Germany:) to be as follows:-
An examination of compounds of antimony and lactic acid has shewn that a
direct combination of lactic acid with antimonic oxide (i.e. a lactate of antimony)
is.only formed and maintained in the presence of a large excess of acid. This
lactate is therefore unsuitable for use in mordanting fibres previously treated with
tannin, because from the strongly acid solution the tannic acid is able to
precipitate upon the fibre but very little of the antimonic oxide employed.
Double salts of antimony lactate with lactates of the alkalies and alkali earths,
produced according to the following process, are more efficient in this respect whilst
others, produced by mixing antimonic chloride with alkalies or alkali earths, are
of little use by reason of the large amount of acid required to retain them in
solution.
The following is a method of producing a double lactate of antimony which is
very suitable for mordanting direct without addition of acid, since under ordinary
conditions of working it yields the whole of its antimony to the tannic acid, that
is to the fibre:-
One molecule of antimony oxide is digested in heat with two molecules of acid
lactate of calcium. This produces a clear solution of antimonic oxide. From this
solution there may be obtained by evaporation by heat, a white crystalline
substance which is however very hygroscopic and cannot therefore be kept at a
fixed constant percentage of antimony and for this reason an unalterable
concentrated solution is more suitable for mordanting purposes.
In order to produce upon 100 kilos of cotton previously treated or mordanted in
he usual way with 5% tannin, as strong a mordanting effect as that produced
with 2.5 kilos of tartar emetic containing 43% of antimonic oxide (or with 2.5
ilos of antimony-fluorate of ammonium sulphate having 46% of antimonic oxide),
may employ 2.5 litres of a solution of the aforesaid antimony calcium lactate
ontaining 120 grammes of antimonic oxide to the litre.
Analysis of the exhausted or spent mordanting baths has shewn that no
listinguishable traces of antimonic oxide are left in the antimony.calcium lactate
ath, that is to say the whole of the antimony has been utilized; whereas there is
till contained:-
(a) In the tartar emetic bath 28% of the quantity of antimonic oxide used;
(b) In the antimony fluorate-ammonium sulphate bath 22% of the quantity of
ntimonic oxide used."
The obvious explanation of this fact is that in using antimony calcium lactate
he antimonic oxide is taken up by the tannic acid and the acid lactate of calcium
ormed is not able to dissolve the tannate of antimonic oxide, whereas in the other

page_text: cases the free acids formed either prevent in part the formation of tannate of
antimonic oxide or re-dissolve it.
The new mordanting process hereinbefore described enables a very material
saving of antimony to be effected, a large amount of antimony having been hitherto
lost in consequence of the non-exhaustion of the antimony baths.
Dated this 10th day of October 1896.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
COMPLETE SPECIFICATION.
An Improved Mordanting Agent and Process for Vegetable Fibres.
I, ALEXANDER MELVILLE CLARK of the Firm of A. M. & Wm. Clark of 53
Chancery Lane in the County of Middlesex, Fellow of the Chartered Institute of
Patent Agents do hereby declare the nature of this Invention (a communication
to me by the Firm of C. I. Boehringer Sohn of the Chemical Works, Niederingel-
heim-on-the-Rhine, Germany;) and in what manner the same is to be performed
to be particularly described and ascertained in and by the following statement:-
. An examination of compounds of antimony and lactic acid has shewn that a
lactate of antimony produced by the direct combination of lactic acid with anti-
imonic oxide is only formed, and only remains stable, in the presence of a large
excess of acid. This lactate. is therefore unsuitable for use in mordanting fibres
which have been previously treated with tannin, because from the strongly acid
solution the tannic acid is able to precipitate upon the fibre but very little of the
antimonic oxide employed.
Double salts of antimony lactate with lactates of the alkalies and alkali earths,
produced according to the following process, are more efficient in this respect whilst
others, produced by mixing antimonic chloride with alkalies or alkali earths, are
of little use by reason of the large amount of acid required to retain them in
solution.
The following is a method of producing a double lactate of antimony which is
very suitable for mordanting direct without addition of acid, since under ordinary
conditions of working it yields the whole of its antimony to the tannic acid, that
is to the fibre:-
One molecule of antimony oxide is digested in heat with two molecules of acid
lactate of calcium. This produces a clear solution of antimonic oxide. From this
solution there may be obtained by evaporation by heat, a white crystalline
substance which is however very hygroscopic and cannot therefore be kept at a
fixed constant percentage of antimony and for this reason an unalterable
concentrated solution is more suitable for mordanting purposes.
In order to produce upon 100 kilos of cotton previously treated or mordanted in
the usual way with 5% tannin, as strong a mordanting effect as that produced
with 2.5 kilos of tartar emetic containing 43% of antimonic oxide (or with 2.5
kilos of antimony-fluorate of ammonium sulphate having 46% of antimonic oxide)
I may employ 2.5 litres of a solution of the aforesaid antimony calcium lactate
containing 120 grammes of antimonic oxide to the litre.
Analysis of the exhausted or spent mordanting baths has shewn that no
distinguishable traces of antimonic oxide are left in the antimony calcium lactate
bath, that is to say the whole of the antimony has been utilized; whereas there
still remains in the tartar emetic bath 28% of the quantity of antimonic oxide used
and in the antimony fluorate-ammonium sulphate bath 22% of the quantity of
autimonic oxide used.

page_text: The obvious explanation of this fact is that in using antimony calcium lactate
the antimonic oxide is taken up by the tannic acid and the acid lactate of calcium
formed is not able to dissolve the tannate of antimonic oxide, whereas in the other
cases the free acids formed either prevent in part the formation of tannate of
antimonic oxide or re-dissolve it.
The new mordanting process hereinbefore described enables a very material
saving of antimony to be effected, a large amount of antimony having been hitherto
lost in consequence of the non-exhaustion of the antimony baths.
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 antimony calcium lactate from antimonic oxide and acid
calcium lactate substantially as and for the purpose specified.
2. In the process of mordanting vegetable fibres with tannic acid, the preparation
and use of a bath composed of antimony calcium lactate whereby to enable the
whole of the antimonic oxide to be utilized as specified.
Dotad this 25th day of Mox 1807
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.