Improvements in the Treatment of Jute Bast, China Grass, Rhea, and like Plants for use in Textile Industries.
Year: 1897

page_text: Date of Application, 12th May, 1897--Accepted, 7th Aug., 1897
COMPLETE SPECIFICATION.
Improvements in the Treatment of Jute Bast, China Grass, Rhea, and
like Plants for use in Textile Industries.
I, AUGUST HERMANN PRINZ, of 46 Baumgartenstrasse, Baumgarten, Vienna,
Austria, 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:-
My Invention has for its object the extraction of cellulose from plant fibres
without the aid of heat in order to better adapt such fibres for use in textile
industries.
By way of example, I shall in the following description, apply my process to the
extraction of fibres from jute bast, although I may in a similar manner extract fibres
from china grass, rhea and other vegetable matter.
1. Mechanical treatment of the crude jute bast. The stricks of jute are loosened
by mechanical means with a machine of known construction. The loosened jute bast
is freed by hand or by machinery from the tips and root ends in order to obtain the
jute bast in as uniform a state as possible.
2. Chemical treatment. The jute bast mechanically treated in the manner above
described is first subjected to a macerating process in an alkiline solution and without
the aid of heat.
A. MACERATING PROCESS.
I have discovered in the course of my experiments that caustic soda lyes are most
suitable and economical for such maceration. To macerate without the aid of heat, I
use by way of example caustic soda lyes having a specific gravity of 1035 and I have
noticed that the concentration of the macerating lyes varies according to the quality of
the jute bast under treatment. The macerating process has for its object the opening
of the intercellular substance of the jute or vegetable fibres and to prepare the
incrustations for the subsequent chlorination process, while not impairing the solidity
of these fibres by their maceration with alkalies.
This macerating process is carried on in the following manner :
a. The jute bast cut into lengths of about from 1 to 1.5 metres and freed from root
ends and tips, is laid lengthwise in a sheet iron receptacle having a double perforated
bottom and an outlet cock, 5 cubic metres of crude jute bast may, by way of example,
be placed in such a receptacle.
6. After having thus laid the jute bast in the reservoir, the caustic soda lyes of a
specific gravity of 1.035 are added thereto say for instance 700 litres (in volume) of
such lyes to 100 kilos. of crude jute bast.
6. To operate with economy, that is to say, to carry on the treatment with the

page_text: smallest possible quantity of caustic soda lyes, I proceed by successive stages in the
following manner for instance.
GAD DIAVE.
100 kilos. of crude jute bast are macerated with the lyes expressed and discharged
from the first stage with the addition of 200 litres of fresh caustic soda lyes of the
same specific gravity of 1.035 in order to increase the volume of the said lyes which
remain from the 100 kilos. of jute bast after expression.
3RD STAGE.
The whole of the lyes expressed and discharged from the second stage with an
addition of 200 litres of fresh caustic soda lyes of a specific gravity of 1.035 are used
to increase the volume and treat a third 100 kilos. of jute i.e. to economically macerate,
according to the indications furnished under 1, 300 kilos. of crude jute bast, which
is thus treated by 1100 litres instead of by 700 × 3=2100 litres of caustic soda lyes.
c. The duration of the maceration that is to say the time during which the caustic
soda lyes is allowed to act on the jute bast in the receptacle should amount to about
from 4 to 6 hours at an ordinary temperature that is to say without the aid of
heat.
d. After the lapse of this maceration time of about 4 to 6 hours, the macerating
lyes are drawn off from the receptacle by the discharge cock and the macerated jute
bast is removed from the said receptacle and freed from the macerating lyes which it
may still contain by means of iron cylindrical rollers; the drawn off as well as the
expressed lyes from the first stage of the operation being utilized to macerate, with
the addition of fresh yes as indicated under b', the jute bast in the second stage
which is carried on in the same manner as the first stage. After the third stage of the
no further used and are thrown
macerating process, the macerating lyes are
away.
B. III. CHLORINE PROCESS.
The jute bast macerated in the caustic soda lyes and freed therefrom by expression
contains about 7% of fixed caustic soda and is subjected to a chlorine process.
e. In a chlorine chamber preferably made of brickwork lined internally with enamelled
tiles and provided with a trellis of wooden laths or the like as a support for the
macerated jute bast, the macerated and expressed jute bast being suspended length-
wise in the chlorine chamber on the said trellis. As soon as this chlorine chamber is
closed gas tight and the lead pipe which starts from the centre thereof has been
connected to the chlorine generating apparatus, chlorine gas is admitted into the said
chamber. The duration of the chlorine process depends on the quantity of the jute
to be treated and on the bulk of the charge of the manganese salts and sulphuric acid;
for example, with a preparation of 100 kilos. of crude jute bast, the duration is
from 8 to 12 hours.
..
f. According to my experiments 100 kilos. of jute bast require as much chlorine
for the chlorination process as is produced by the mixture of 30 kilos. of peroxide
of manganese having a yield of from 60 to 70% 60 kilos. of chloride of sodium and
120 kilos. of sulphuric acid at 58° Beaumé.
g. This chlorine process for the treatment of the macerated jute has for its object
(in presence of the caustic soda contained in the macerated and expressed jute bast
submitted, according to the indications furnished under d, to the chlorine treatment)
to form a compound with the incrustations, and in particular with the rosin "Jutin "
discovered by me in the jute bast, which compound is subsequently entirely removed

page_text: in the course of the following cold treatment owing to its being readily dissolved.
The aforesaid "Jutin "is a rosin in composition similar to common or yellow rosin
and is a particular ingredient of the crude jute bast.
C. IV. RECUPERATION OR PURIFICATION OF THE CHLORINATED JUTE BAST WITH
CAUSTIC SODA LYES.
h. After having been subjected to the chlorine process, the chlorinated jute which
has now an acid reaction is removed from the chlorine chamber and is washed with cold
water in a suitable washing machine until the washing water ceases to have an acid
reaction whereupon the washed jute is subjected to a process of revivification. For
this purpose the chlorinated and clean washed jute is transferred to a reservoir of
sheet iron being placed lengthwise therein. As soon as the jute is placed in the
reservoir, the chlorinated jnte is covered with caustic soda lyes of a specific gravity
of 1.035 until the level of the lyes is above that of the jute. 100 kilos. of chlorinated
jute bast require, according to experiments, about 417 litres of caustic soda lyes of a
specific gravity of 1.035 to carry out revivification process, the lyes being left for
about 6 hours in contact with the chlorinated jute bast.
i. After this time the lyes are removed from the jute bast and as they are discharged
they have assumed in consequence of the dissolved incrustations a dark reddish
brown colour. The jute bast left in the reservoir which is now entirely free from
incrustations and appears in the form of fine fibres is washed in the same reservoir
with cold water until the washing water is thoroughly clean and has no alkaline
reaction whatsoever. These clean washed jute fibres are now subjected to a bleaching
treatment.
D. V. BLEACHING OPERATION.
k. The purified and cleanly washed jute fibres treated according to the indications
furnished under i, are placed for this purpose in a reservoir preferably made of cement.
It is advisable to have the bottom of the bleaching reservoir covered with a wooden
trellis (double bottom) or the like, so that the bleaching lyes may come, through the
opening in the trellis work uniformly in contact with every portion of the jute fibres
thus laid on such trellis. As soon as the jute fibres have been transferred to the
bleaching reservoir, the bleaching lyes are poured thereon, in the form of an aqueous
solution of a hypo-chlorite of soda having a specific gravity of 0.5 Beaumé, until the
jute fibres are covered over by the same.
1. By using hypo-chlorite of soda as bleaching means for the jute fibres, I derive
an advantage, as compared with the bleaching means hitherto used that is to say with
a solution of chloride of lime, in so far that by the use of hypo-chlorite of soda as
bleaching means no lime can adhere to the fibres, i.e. no lime particle can become
fixed in the intercellular substance of the fibres, whereas in the bleaching of fibres by
means of a solution of chloride of lime or chloride of lime lyes there was a deposit of
lime on the fibres which could not be removed by a long washing operation and which
was the ultimate cause of their brittleness and rigidity.
m. The jute fibres are left in the bleaching bath from about 4 to 6 hours, after
which the bleaching lyes are drawn off from the jute fibres while the latter are left in
the bleaching reservoir for another 2 or 4 hours so as to be still further bleached.
n. The duration of this further bleaching as above set forth is a matter of great
importance as the particles of bleaching lyes still adhering to the jute fibres
(hypochlorite of soda) is regenerated by the absorption of oxygen from the air and
supplies oxygen in a highly oxidizing state (in statu nascente) to the jute fibres which
oxygen or ozone acts as a powerful bleaching means, so that this subsequent bleaching
permits of fully benefiting by the utilization of the bleaching process.
o. After the bleaching has been effected according to the indications furnished
under m and n the jute fibres are removed from the reservoir and are washed with

page_text: cold water in a suitable washing machine until the bleached and washed jute fibres
cease to give a chlorine reaction.
p. The bleached and well washed jute fibres are subsequently drained and dried at
a temperature of about 40° C.
The crude jute fibres treated in the manner above indicated appear after being
bleached and dried as a fibre which is entirely free from incrustations or impurities
having a particularly beautiful silky gloss, and when such fibres are spun into yarns and
woven into fabrics either alone or mixed with wool and silk, they make a product
hitherto unknown in the textile industries.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what I
claim is
1. A new or improved process characterized by the maceration, without the aid of
heat, of crude jute bast, china grass and other plants by means of caustic soda lyes
according as set forth in the description under the headings bb' c and d in section A,
this cold maceration of the vegetable fibres with caustic soda lyes having particularly
for its object to open the inter-cellular substance of the jute or vegetable fibres and to
prepare the incrustations for the subsequent chlorination process, while moreover not
impairing the solidity of these fibres by their cold maceration with alkalies.
2. A new or improved process characterized by the chlorine treatment that is to say
by the chlorination of the fibres macerated in caustic soda lyes according as set forth
under the headings e, f and g in section B, this chlorine process having for its object
to convert, by the direct action of chlorine gas on the fibres macerated in caustic soda
lyes, the incrustations into a chlorine compound which is subsequently removed by
the purification indicated under headings h and i section C with the aid of caustic
soda lyes, without the aid of heat and without injuring the fibres of these plants and
with but a very trifling loss of fibres.
3. A new or improved process characterized by the use of hypochlorite of soda as
bleaching means according as set forth under the headings k, l, m and n in the
description.