Improvements in the Mode of Bleaching Rhea, Ramie, China Grass and other Vegetable Fibres, and Undyed Fabrics Made from Vegetable Fibres.
Year: 1895

page_text: Date of Application, 27th May, 1895
Complete Specification Left, 26th Feb., 1896-Accepted, 28th Mar., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Mode of Bleaching Rhea, Ramie, China Grass
and other Vegetable Fibres, and Undyed Fabrics Made from
Vegetable Fibres.
We RALPH WALDO EMERSON MACI VOR of No. 31 Fleet Street London
Professor of Chemistry and JOHN CHESTER of No. 1 Brick Court Temple
London Barrister-at-Law, do hereby declare the nature of this invention to be as
follows:-
If fibres are to be bleached they should preferably be in a condition of freedom
from bark and gum resin and (for convenience of treatment) should be contained in
a wide meshed cage. They should then be thoroughly washed in hot water and
then immersed in a vat or bath of water to which peroxide of hydrogen has been
previously added.
A solution of permanganate of potash is then poured into the vat or bath and
the cage containing the fibre should then be moved to and fro in the liquid
until the bleaching is accomplished.
If fabrics are to be bleached they should be washed thoroughly in hot water
and then treated in the manner above directed with regard to fibres except that
the fabrics need not be contained in a cage.
Dated this 27th day of May 1895.
R. W. EMERSON MACIVOR.
JOHN CHESTER.
COMPLETE SPECIFICATION.
Improvements in the Mode of Bleaching Rhea, Ramie, China Grass
and other Vegetable Fibres, and Undyed Fabrics Made from
Vegetable Fibres.
We, RALPH WALDO EMERSON MACIVOR, of No. 31, Fleet Street, London,
Professor of Chemistry and JOHN CHESTER, of No. 1, Brick Court, Temple,
London, Barrister-at-Law, 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 :-
This invention has for its object improvements in the mode of bleaching rhea
ramie China grass and other vegetable fibres and undyed fabrics made from
vegetable fibres.
When fibre is to be treated all bark (if any) and resin or gum (if any) is iu the
first place removed and then the fibre should be thoroughly washed in hot water.
Afterwards the fibre is to be immersed in a solution in water of permanganate of
potassium or sodium, not exceeding in strength one and a quarter per cent. The
immersion should be continued for a period not exceeding two hours.
At the end of the period of immersion a solution of peroxide of hydrogen of a
strength not exceeding 2 per cent. should be added to the fluid in which the fibre
has been immersed and such solution should be added in the proportion 1quired
Price 8d.1

page_text: to completely decompose the permanganate in the bath and this will be indicated
by the solution losing its purple colour. After remaining in the bath for a further
period of half an hour the fibre is removed from the bath and thoroughly washed.
Any oxide of manganese which may be found adhering to the fibre after washing
may be removed by rinsing in water containing a small quantity of bisulphite of
soda. After again rinsing in water the fibre is dried. We have stated above
the maximum strengths which we consider it expedient to employ but for fibres
which are easily bleached much weaker solutions and a less prolonged treatment
will suffice.
It is advisable always to make preliminary trials on small samples of the fibre 1
and to regulate the treatment accordingly using as weak solutions as the nature
and condition of the fibre admits.
Fabrics made from vegetable fibre are treated in a similar manner.
The order of the process may be reversed the peroxide of hydrogen being first
applied and the permanganate afterwards added. In either case the result is that 1
nascent oxygen reacts on the coloring matter of the fibre.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
The subjection of vegetable fibres and fabrics to the combined action of
permanganate and peroxide of hydrogen substantially as described wherefrom
bleaching results.
TA 1
2000
R. W. EMERSON MACIVOR.
JOHN CHESTER.