Improvements in the Treatment of Logwood Colouring Matter.
Year: 1897

page_text: Date of Application, 9th June, 1897
Complete Specification I oft Oth Mor 1808 Accented 20th Mov
1808
PROVISIONAL SPECIFICATION.
Improvements in the Treatment of Logwood Colouring Matter.
We, JAMES EDWARD BEDFORD and CHARLES SAMUEL BEDFORD, both of 27.
Kirkstall Road, in the City of Leeds, Chemists, do hereby declare the nature of
this invention to be as follows:-
-
This invention has for its object the oxidation of the logwood colouring matter
either in extract form or in the dyebath by means of manganese dioxide.
It is well known that a decoction of fresh logwood is unsuitable for dyeing
certain classes of woollen goods especially those which require redyeing such as
torn woollen rags. If logwood be rasped and aged in the ordinary manner the
colouring matter within the wood is then in a more favourable condition for dyeing
these articles.
We effect the oxidation of decoctions of fresh logwood by allowing the liquors
with or without addition of acetic acid to stand for some hours in contact with
finely divided manganese dioxide at the ordinary or a slightly elevated tempera-
ture agitating by means of a current of air or some stirring device.
As soon as the liquors have developed a deep brown red colour, a sample tinting
cold water cherry red, we allow the manganese dioxide to settle out & concentrate
the supernatent liquid in a vacuum pan to the requisite density.
We also dye woollen goods with fresh logwood or decoctions or dried extracts
of fresh logwood by addition of manganese dioxide to the dyebath or by admix-
ture of that substance with the decoctions or dried extracts.
Dated this 7th day of June 1897.
JAMES E. BEDFORD.
CHAS. S. BEDFORD.
COMPLETE SPECIFICATION.
Improvements in the Treatment of Logwood Colouring Matter.
We, JAMES EDWARD BEDFORD and CHARLES SAMUEL BEDFORD, both of 27,
Kirkstall Road, Leeds, in the County of York, Chemists, 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 the oxidation of the logwood colouring matter
either in extract form or in the dyebath by means of manganese dioxide.
It is well known that a decoction of fresh logwood is unsuitable for dyeing
certain classes of woollen goods especially those which require redyeing such as
torn woollen rags. If logwood be rasped and aged in the ordinary manner the
D017

page_text: colouring matter within the wood is then in a more favourable condition for dyeing
these articles.
We effect the oxidation of decoctions of fresh logwood by allowing the liquors
with or without addition of acetic acid to stand for some hours in contact with
finely divided manganese dioxide at the ordinary or a slightly elevated tempera-
ture agitating by means of a current of air or some stirring device.
As soon as the liquors have developed a deep brown red colour a sample tinting
cold water cherry red, we allow the manganese to settle out and concentrate the
supernatent liquors in a vacuum pan to the requisite density.
In order to effect the oxidation simultaneously with the extraction of the
colouring matter we add manganese dioxide to the chipped logwood in the
extracting vessels. These vessels are of copper & of the usual form each capable of
holding 1 ton of chipped logwood. They are connected together in series so that
the liquors from No. 1 may flow on to the fresh logwood contained in No. 2 &
from thence in similar manner to the logwood in No. 3. From the last vessel the
liquors pass to the vacuum pan for concentration.
Each vessel is charged with 1 ton of chipped logwood, 60 lbs. manganese dioxide
being scattered in with the wood during the filling. The colouring matter is then
extracted in the usual way by successive boilings with water. Usually six liquors
are sufficient to remove most of the colouring matter but the last portions are
removed by an alkaline boil formed by addition of 50 lbs. sodium carbonate to
each vessel as the liquor is circulated round. This alkaline liquor is neutralised
before evaporation.
The liquors are concentrated to 52° Twaddle.
We also dye woollen goods with fresh logwood or decoctions or dried extracts
of fresh logwood by addition of manganese dioxide to the dyebath or by admix-
ture of that substance with the decoctions or dried extracts.
Chipped ligwood requires in the dyebath an addition of 4% manganese dioxide
to effect the oxidation. Logwood extract of 45°-50° Twaddle, 15 to 20 % by
weight.
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:
-
1. The use of manganese dioxide for the oxidation of logwood colouring matter
in order to render the same more suitable for wool dyeing.
°
2. The employment of manganese dioxide in the extraction of logwood for the
preparation of oxidised logwood extract or hematin.
Dated this Eighth day of March 1898.
JAMES E. BEDFORD.
CHAS. S. BEDFORD.