IMPROVEMENTS IN BLEACHING SILK AND OTHER FIBRES
Year: 1875

page_text: LETTERS PATENT to Thomas James Smith, of the Firm of Robertson,
Brooman, and Company, of 166, Fleet Street, in the City of London,
Patent Agents, for the Invention of "IMPROVEMENTS IN BLEACHING
SILK AND OTHER FIBRES."-A communication from abroad by Cyprien
Marie Tossié du Motay of Paris, France.
PROVISIONAL SPECIFICATION left by the said Thomas James Smith
at the Office of the Commissioners of Patents, with his Petition,
on the 10th August 1875.
I, THOMAS JAMES SMITH, of the Firm of Robertson, Brooman, and
Company, of 166, Fleet Street, in the City of London, Patent Agents,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
BLEACHING SILK AND OTHER FIBRES," (communicated to me from abroad by
Cyprien Marie Tessie du Motay, of Paris, France,) to be as follows:―
The object of my Invention is a new method of bleaching, par-
ticularly applicable to silks from the wild silkworm, to Tussah or Tussore

page_text: silks, and to other silks or fibres of animal origin which hitherto have
been bleached only by the ordinary processes, and generally to all silks
and wools which alkalis, soap, and sulphurous acid bleach insufficiently.
The base of this method is the employment of binoxide of barium alone
or of the same binoxide with the addition of either permanganic acid
or the permanganates of magnesia and lime, or a mixture of these per-
manganates with alkaline permanganates.
The manner of operating is as follows:-Into a bath of boiling water
intended for the bleaching I add, in the state of-finely pulverized powder,
binoxide of barium, previously washed in order to separate it from the
free baryta which it may contain, or which has undergone the action.
of carbonic acid in order to attain the same object.. This binoxide is
very little soluble, but at the temperature of the bleaching bath from
30° to 90° centigrade it yields up little by little to the fibres and tissues
of vegetable origin its oxygen in the nascent state without the aid of any
intermediate body such as an acid.
The bath of warm water and of binoxide of barium prepared, I plunge
therein the fibres or fabrics to be bleached, and I maintain the bath at
a temperature ranging between 30° and 99° centigrade during one or
two hours when silks in general and silks from the wild silkworms in
particular is being acted upon, and at a less elevated temperature when
wools or other bodies of a like nature, such as when goats' or other
hair is under operation. This having been accomplished, the substances
submitted to the bleaching are washed and steeped in acidulated water,
and then after a last washing in pure water they are dried when they
have attained the degree of whiteness desired, or steeped again in a
second bath of water and binoxide of barium when they still contain
colouring matters, and so on until they are perfectly bleached.
The quantity of binoxide of barium employed for bleaching silks from
the wild silkworm, and especially Tussah or Tussore silk, varies from 50
to 100 per cent. of the weight of the material to be bleached.
Silks of other kinds and wools are bleached by a very much less pro-
portion of binoxide.
When the consecutive action of the bath containing the binoxide
of barium is not sufficient for the complete bleaching of silks and wools,
I have recourse to the employment of several cold baths containing
i

page_text: in solution either permanganic acid or permanganate of magnesia or lime,
or a mixture of these latter permanganates with alkaline permanganates.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas James Smith in the Great Seal Patent'
Office on the 8th February 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
JAMES, SMITH, of the Firm of Robertson, Brooman, and Company, of
166, Fleet Street, in the City of London, Patent Agents, send greeting.
1
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing, date the Tenth day of August, in the year of
our Lord One thousand cight hundred and seventy-five, in the thirty-
ninth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas James Smith, Her special license
that I, the said Thomas James Smith, my executors, administrators,
and assigns, or such others as I, the said Thomas James Smith, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN BLEACHING SILK AND OTHER FIBRES," (communicated to me
from abroad by Cyprien Marie Tessic du Motay, of Paris, France,) upon
the condition (amongst others) that I, the said Thomas James Smith,
my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Thomas James Smith, do hereby'

page_text: is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say:
-
The object of this Invention is a new method of bleaching fibres of
an animal origin. It is particularly applicable to silks from the wild
silkworm, to Tussal or Tussore silks, to silks from silkworms feeding
upon oak, and to other silks which hitherto have not been capable of
being bleached by the ordinary processes, and generally to all silks and
wools which soap and sulphurious acid bleach insufficiently. The base
of this method is the employment of binoxide of barium alone, or of
the same binoxide of barium, with the addition of either permanganic
acid or the permanganates of magnesia and lime, or a mixture of these
permanganates with alkaline permanganates.
Instead of the manganic compounds just mentioned I can also
employ aqua regia or a solution of oxygenated water in hydrochloric
acid.
The manner of operating is as follows:-Into a bath of boiling water
intended for the bleaching I add, in the state of finely pulverized powder,
binoxide of barium, previously washed in order to separate it from the
free baryta which it may contain, or which has undergone the action
of carbonic acid in order to attain the same object. This binoxide is
very little soluble, but at the temperature of the bleaching bath from 30°
to 90° centigrade it yields up little by little to the fibres and tissues of
vegetable origin its oxygen in the nascent state without the aid of any
intermediate body such as an acid.
The bath of warm water and of binoxide of barium prepared, I plunge
therein the fibres or fabrics to be bleached, and I maintain the bath at
a temperature ranging between 30° and 90°, or even 100° centigrade,
during one or two hours when silks in general and silks from the wild silk-
worm in particular is being acted upon, and at a less elevated temperaturo
when wools or other bodies of a like nature, such as goats or other hair
is under operation. In the latter case to quicken the action of the
binoxide I add to the bath caustic soda or caustic potash. This having
been accomplished, the substances submitted to the bleaching are washed
and steeped in acidulated water, and then after a last washing in pure
water they are dried when they have attained the degree of whiteness
desired, or steeped again in a second bath of water and binoxide of

page_text: barium if they still contain colouring matters, and so on until they are
perfectly bleached.
The quantity of binoxide of barium employed for the bleaching silks
from the, wild silkworm, and especially Tussah or Tussore silks, varies
from 50 to 100 per cent. of the weight of the material to be bleached.
Silks of other kinds and wools are bleached by a very much less pro-
portion of binoxide, according to their nature.
When the consecutive action of the bath containing the binoxide of
barium is not sufficient for the complete bleaching of silks and wools I
have recourse to the employment of one or several cold baths containing
in solution either permanganic acid or permanganate of magnesia or
lime, or a mixture of these latter permanganates with alkaline perman-
ganates, aqua regia, or a solution of oxygenated water in hydrochloric
acid.
By the above described method all the substances of animal origin can
be completely deprived of colour without alteration.
And having now described the nature of the said Invention, and in
what manner the same is to be performed, I declare that I claim, the
above described method of bleaching silk and other fibres of animal
origin.
In witness whereof, I, the said Thomas James Smith, have here-
unto set my hand and seal, this Eighth day of February, One
thousand eight hundred and seventy-five.