IMPROVEMENTS IN INDIGO VATS AND IN VATS FOR DYEING WITH NOIR BLEU OR WITH MIXTURES OF NOIR BLEU AND INDIGO
Year: 1884

page_text: I, FREDERICK WILLIAM RENAUT, of The Cottage, Burstow (By Crawley), in
the County of Surrey, do hereby declare the nature of the said invention for
"IMPROVEMENTS IN INDIGO VATS AND IN VATS FOR DYEING WITH NOIR BLEU
OR WITH MIXTURES OF NOIR BLEU AND INDIGO" to be as follows:-
--
This invention relates to the Indigo Vats used by dyers, and to similar vats in
which Indigo is replaced either partially or entirely by the material which is
known in France as Noir Bleu, and which will hereinafter be spoken of as Blue
Black.
In such vats, the colouring matter employed has to be reduced. There are
various kinds of such vats, depending upon different methods of effecting the said
reduction. The kind most generally employed is one in which the reduction
depends on the fermentation of various organic matters. It is to this latter kind
of such vats that the present invention relates.
For the bran and molasses which are at present used in the vats in question, by
their present invention my correspondents substitute glucose or grape sugar and
soluble starch, or one or both of these, and they prefer to use also, in addition
to the quantity of alkali necessary to form indigotate, or other corresponding
compound, as will be well understood, either calcined magnesia or finely divided
carbonate of magnesia.
The fermentation which takes place in vats composed according to the present
invention is always fermentation of grape sugar or glucose, the soluble starch used
in it being converted in the vats first into dextrine and then into glucose.
As the glucose ferments, there is a disengagement of hydrogen and carbonic acid,
and formation of an acid or acids which enter into solution. If these latter were
not neutralized as they form, colouring matter would be precipitated thereby.
The vat must therefore contain a base which shall combine with these acids as
they are produced, but this base must not be a soluble one, or the vats would
be too alkaline to permit the necessary fermentation. It is for the purpose of

page_text: neutralizing the acid or acids which form during the fermentation, without
rendering the vats too alkaline, that my correspondents thus propose to employ,
in addition to the alkali necessary to form indigotate or other corresponding
compound, calcined magnesia or finely divided carbonate of magnesia.
The loss of colouring matter which takes place in the fermentation vats which
have been used hitherto frequently amounts to as much as fifty per cent. This
loss can be wholly avoided by composing the vats according to the present
invention. Moreover, the magnesia or calcined magnesia gives the vats a more
brilliant colour; while the materials used tend to cause the Indigo or Blue Black
to be held in suspension, and so to enable it to become reduced more rapidly than
when it lies at the bottom of the vats as at present.
The starch to be used under this invention should first be boiled for a few
minutes with a sufficient quantity of water, in which is dissolved one part of
carbonate of soda or thereabout for each ten parts of starch so treated.
The. ferment used in vats composed according to the present invention may
either be the ferment which is ordinarily used in fermentation vats, or any other
suitable ferment; but my correspondents prefer the ferment prepared according to
another invention of theirs, an application for a patent for which will be deposited
at the Patent Office on the same day as the present specification.
What is new in this invention thus consists:
Firstly, in employing, in fermentation vats for the reduction of Indigo or of Blue
Black, or of a mixture of both Indigo and Blue Black, soluble starch and grape
sugar or glucose, or one or both of these; and,
Secondly, in employing therein also calcined magnesia or finely divided carbonate
of magnesia, substantially as is above described.

page_text: I, FREDERICK WILLIAM RENAUT, of The Cottage, Burstow, in the County of
Surrey, Secretary, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN INDIGO VATS AND IN VATS FOR DYEING WITH NOIR BLEU OR WITH
MIXTURES OF NOIR BLEU AND INDIGO," (a Communication from Charles Collin
and Lucien Benoist, both of Paris, in the Republic of France) and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This invention relates to the indigo vats used by dyers, and to similar vats in
which indigo is replaced either partially or entirely by the material which is known
in France as Noir Bleu, and which will hereinafter be spoken of as Blue Black.
In such vats, the colouring matter employed has to be reduced. There are
various kinds of such vats, depending upon different methods of effecting the said
reduction. The present invention relates to vats in which the reduction of the
colouring matter is effected by the fermentation of organic bodies, and it consists in
employing in such vats certain fermentiscible bodies which have not hitherto been
employed therein.
The fermentiscible materials, the use of which in vats for dyeing either with
indigo, with blue black, or with a mixture of indigo and blue black, thus constitutes
the present invention, are glucose or grape sugar, and starch which has been
rendered soluble by boiling it with a dilute solution of carbonate of soda, or by
other equivalent means.
Starch to be used under the present invention may conveniently be prepared for
use in the vats in which it is to be employed by boiling it for a few minutes with
a sufficient quantity of water in which one part of carbonate of soda or thereabout
is dissolved per ten parts of starch so treated. The proportion of water to starch
is not very material, but ten of water to one of starch answers very well.
In the vats, starch does not undergo fermentation until it has undergone
conversion first into dextrine and then into glucose. The material by the fermen-
tation of which indigo and blue black are reduced by the present invention is thus
always glucose, such glucose being either supplied to the vat as already formed
glucose, or being formed in the vat itself from starch. The ultimate result is thus
the same, whether the vats be fed with starch only, of with a mixture of starch and
glucose in whatever proportions; but the fermentation takes place more rapidly
when the vats are fed with ready formed glucose than when they are fed with a
material which has first to be converted into glucose in the vats themselves.
Hence, whether starch. only is used, or glucose only, or both glucose and starch, and
in the latter case in what proportions, must depend on the rapidity with which it
is desired that fermentation should take place.
It will be well understood by practical men that fermentation vats must be
supplied, not only with fermentiscible material, but also with an alkali to combine
with the reduced colouring matter and with the acids formed during the fermen-
tation taking place in the vats. It is customary, in the fermentation vats at
present in use, to employ both soda and lime; but my correspondents have found
it better not to employ lime. They prefer to employ soda only, or potash only, or
a mixture of soda and potash.
Soda, as being the cheaper alkali, will usually be preferred. My correspondents,
though they do not confine themselves to such proportions, have found that, when
using soda in vats supplied with glucose or starch or both, from 45 to 67-parts of
soda per 100 parts of starch, or per 100 parts of glucose, or per 100 parts of total
starch and glucose are suitable proportions. The smaller proportion usually suffices

page_text: during the ordinary working of the vat, but the larger proportion is usually
necessary during the six or seven days required for the preparation of a new vat.
My correspondents have found that about four parts of starch, or four parts of
glucose (meaning thereby the quantity of commercial or other glucose containing
four parts of real glucose) or a total of four parts of glucose and starch, used in
whatever proportions one to the other, suffice, as sustenance for a working vat, for
the reduction of about five parts of indigo of average quality that is to say, of
indigo containing about 60 per cent. of indigotine. In vats in which indigo is used
in admixture with blue black, no additional quantity of starch or glucose, above.
the quantity thus indicated for indigo alone, need be employed. When blue black
is employed without indigo, the proportion of starch or glucose employed may vary
considerably, but smaller proportions than those indicated for indigo alone will
suffice.
In mounting new vats, the fermentiscible material or a part of the fermentiscible
material to be supplied to which is starch or glucose or a mixture of both, my
correspondents prefer to use the ferment prepared by their other invention an
application for a patent for which was deposited at the Patent Office on the
29th. April, 1884, and was numbered 6973. The temperature at which fermentation
best takes place under the influence of this ferment is from 50 to 52 degrees
Centigrade, or from about 122 to 126 degrees Fahrenheit. The vats may be main-
tained however at about 48 degrees Centigrade, or about 118 degrees Fahrenheit,
without disadvantage.
In order that the proper working of the vat should not be interfered with by the
production of fermentations other than that produced by the ferment just referred
to, the temperature of the vat should preferably from time to time be raised to
from 70 to 80 degrees Centigrade, or to from about 158 to 176 degrees Fahrenheit,
since this temperature kills most of the organisms which would produce prejudicial
fermentations, but does not kill the ferment which my correspondents have found
to produce the most favourable results.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is the use, as the fermentiscible material, or part of the fermentiscible
materials, to be employed in fermentation vats for the reduction of Indigo, or of
Blue Black, or of any mixture of both Indigo and Blue Black, of either starch
which has been rendered soluble, or glucose, or both starch and glucose.
Dated this first day of December 1884.