Improvements in the Treatment of Exogenous Fibrous Plants, Flax, Jute, Rhea, and the like.
Year: 1887

page_text: Date of Application, 11th Mar., 1887
Complete Left, 7th Dec., 1887
Complete Accepted, 13th Jan., 1888
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Exogenous Fibrous Plants,
Flax, Jute, Rhea, and the like.
We, JAMES LONGMORE, Chemist and WILLIAM LIVINGSTONE WATSON, Merchant
both of Leadenhall Street in the City of London, do hereby declare the nature of
this invention to be as follows:-
This invention is designed for the extraction of fibre from exogenous plants
principally Boehmeria nivea, and the method we prefer to adopt is as follows.
The stems of Boehmeria nivea either in the green or dry state, are made into
bundles of convenient size and boiled for a few minutes in an open vessel in an
alkaline solution usually caustic soda, this dissolves the gun and the outside black
bark is then removed preferably by passing the hand down the stem from end to end.
The fibres thus cleaned are then stripped from the stem and washed in water
and dried.
Instead of removing the outer bark as before described the dried stems may be
dipped in cold concentrated sulphuric acid for a few minutes: this decomposes the
outer bark or pellicle but leaves the gum. The stems are then placed in cold water
and the bark swells up and is then easily removed and the fibre is then stripped or
pulled off.
In some manufactures it is an advantage to have the gum left in but
when it is desired to get rid of this it may be done by one of the well known processes
or by boiling the stems as before described in a solution of caustic soda or potash.
Dated this 11th day of March 1887.
W. P. THOMPSON & BOULT,
Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in the Treatment of Exogenous Fibrous Plants,
Flax, Jute, Rhea, and the like.
We JAMES LONGMORE Chemist, and WILLIAM LIVINGSTONE WATSON, Merchant,
both of 34 Leadenhall Street, in the City of London 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:-
Various and so far insurmountable difficulties have been experienced in the
utilization of this fibre, the object of obtaining filasse completely free from gum,
wood, pith and the outer hark of the plant, without injury to the staple, strength, and
lustre of the fibre not having hitherto been accomplished, except in the case of China
grass in which the objectionable outer bark and part of the gun has been previously
removed by iedious native hand labour.
In the case of machines the fibre prepared invariably contains a proportion of
wood, pith and bark, preventing its being successfully spun and is more or less
bruised and broken, also in any case machine prepared fibre requires to be completed
by a chemical process as it still contains 15 per cent, to 50 per cent. of gum.
In the case of decortication of the stems by hand labor alone, or by steam, or by
boiling in water, and then stripping by hand labor, the separated fibre still contains
all the gum and outer bark, and these methods are valueless in themselves without
the aid of other processes.
Various methods of alkaline treatment have been proposed for dealing with China
grass, and the fibre obtained by the last methods of decortication. In both cases we
have found that although a seemingly finely divided filasse may be obtained, yet that
after the gum has been allowed to dry and set upon the fibre as in the case of ribbons
and China grass, it is impossible to completely or chemically free in from gam
however small the percentage left, and that to this cause is likely to be principally
due the hardness of the woven fabric which has hitherto been a deleci, and as also
producing a coarse fibre increasing the difficulty experienced of spinning line yarns:
moreover this also lessens its capacity and attraction for dyes. We have found that
to overcome this defeet the gum must be removed in the green state before it has set,
or from the stem.
Also in open vessels the prolonged treatment required destroys the chief beauty of
the fibre, its lustre, and renders it harsh. With close vessels and high pressure the
difficulties and risks of working are almost insuperable, and the fibre more or less
suflers. In the case of China grass from which the bark has been removed previously.
the results by these methods are fairly clean but if the ribbons are thus treated the
coloring matter of the bark is diffused over the fibre, entailing extra treatment for its
removal, and the bark itself which is not dissolved by alkalies, is so intimately mixed
with the filasse as to be practically irremovable.
Now we have found that by direct treatment of the fibre on the stem by caustic

page_text: soda, the difficulties that have been stated are obviated, and totally different results
produced from those resulting when the separated ribbons are treated in the
same way.
The process we adopt is as follows
The stems of Boehmeria nivea either in the green or dry state, are made into
bundles of convenient size and boiled in an open vessel with an alkaline solution
preferably of caustic soda. The solution we prefer to use marks 12 degrees Twaddle,
60 degrees Fahrenheit and with this strength, the time necessary is about 15 minutes
the boiling being conducted with as little ebullition as possible. The exact strength
stated is not important as affecting the quality of the fibre produced, and the time
necessary varies with the degree used. If great strength of soda however is used the
fibre is apt to separate completely from the stem in the boiling, and become tangled
and mixed with the outer bark, which interferes with the subsequent operations, and
in the boiling and handling of the stems care should be taken to keep both the outer
bark or pellicle, and the fibre, undisturbed and intact, and as much in their natural
position on the stem as possible. In the boiling the gum is softened and the greater
part of it removed, and the operation may be considered finished when the outer
black bark can be easily detached from the inner layer of fibre by a touch of the
finger. The boiled stems are then placed in a vat of water and allowed to stand in
this for 10 to 12 hours in which time the pasty gum still adhering to the stem and
fibre dissolves oui, together with the excess of alkali and the stems are ready for the
removal of the black outer bark. This could be done immediately after the boiling
but the stems are then strongly alkaline, and the continued action of the caustic
would be apt to affect the hands of the operators; it is therefor advisable first to
remove the excess of alkali by steeping, which at the same time further removes the
gum and much improves the quality of the fibre.
It will be seen that the gum having been thus removed by treating the stem direct,
and without altering the natural position of fibre and bark, the latter remains as an
outer layer covering the inner layer of fibre but quite distinct and without adhesion,
and presenting a round even surface is easily stripped by hand it is therefore
removed by the workman taking the boiled stem by the root end in one hand, then
passing the other with a light pressure rapidly down the stem from root end to thin
end, he strips of the whole of the black bark leaving the clean ungununed fibre on
the stem.
This fibre having no adhesion is easily separated by grasping the ends of
the fibre and pulling it off or shaking the stem oui.
This method of ungumming the stem, and consequently enabling the outer bark to
he removed by hand, therefore obviates the necessity experienced in ungumming
ribbons (in which the bark becomes intimately mixed with the filasse) of subjecting
the fibre to a delicate and complex treatment at great pressure, sufficiently prolonged
and severe to decompose and completely dissolve and remove the bark that this
latter is possible at all, is more than doubtful, but it is quite certain that it cannot be
done practically, without also destroying the fibre. Moreover if a Rhea siem be
examined it will be found that the fibre is in layers; that the inner layer is almost
without gum but the outer is imbedded in and covered with a thick micilage, which
on drying sets like varnish. Now in treating fibres with caustic soda as soon as the
incrusting matters are removed the fibre itself is attacked. It is obvious therefore
that when Rhea ribbons separated from the stem are boiled in caustic soda, the layer
of fibre unprotected by gum will be immediately attacked and affected, long before
the gum surrounding the rest of the fibre is removed. On this account therefore, and
the impossibility of removing the bark the treatment of the ribbons in alkaline
solutions is impracticable. In the case of China grass, all the fibre has become
imbedded in gum by reason of the previous native processes it has gone through, and
though the result is more equal still it requires very careful treatment to preserve
either strength or lustre, the method chiefly in use occupying nearly a fortnight, as
against the 15 minutes on the stem.
On the other hand the construction of the plant favors the application of alkaline
solutions to the stems. The bark is outside and is first attacked then a layer of gum,

page_text: next is a layer of fibre imbedded in gum, while the fibre next the stem which is
unprotected by gum is not reached until the operation is finished which being
conducted in an open vessel can be ascertained at any time.
It is not necessary to continue the soda treataneni sufficiently long to remove all
the gum, but merely to soften and render it. soluble, and thus the staining of the fibre
by the coloring matier of the bark is avoided.
Instead of removing the outer bark as before described the dried stems may be
dipped in cold concentrated sulphuric acid for a few minutes; this decomposes the
outer bark or pellicle but leaves the gum. The stems are then placed in cold
water and the bark swells up and is easily removed and the fibre stripped or
pulled off.
In some manufactures it is an advantage to have the gum left in but
when it is desired to get rid of this it may be done by one of the well known
or by boiling the stems as before described in a solution of caustic soda or potash.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is :-
processes
1. The method of removing the bark and gum from the fibre of exogenous fibrous
plants by treating it while still upon the stem in the manner substantially as
specified.
2. The method of removing the outer bark by first dissolving the gum which holds
it and then stripping off the bark substantially as specified.
3. The method of removing the outer bark by steeping the dry stems in cold
concentrated sulphuric acid.
Dated this 12th day of May 1887.
JAMES LONGMORE.
W. L. WATSON.
Witness,
JNO. D. TANNAHILL,
34, Leadenhall Street, London.