Improvements in or relating to Treating Vegetable Fibres or Fabrics for Dyeing Purposes.
Year: 1895

page_text: Date of Application, 26th Sept., 1895-Accepted, 26th Sept., 1896
COMPLETE SPECIFICATION.
7
Improvements in or relating to Treating Vegetable Fibres or
Fabrics for Dyeing Purposes.
We, RICHARD THOMAS of 110 Blumenthalstrasse and EMMANUEL PREVOST
of 143 Peterstrasse both in Crefeld, in the Empire of Germany, Dyers, 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:-
If vegetable fibres be subjected to the action of strong alkaline lyes or strong
acids the said fibres become chemically changed and acquire a particular property
of attraction or affinity for all colouring or dyeing matters and mordants.
This peculiarity may be utilized for the purpose of producing dark or black
colours upon the vegetable fibre in mixed goods and to impart any other desired
shades to the silk therein whereas heretofore goods of this kind had to be dyed in
the hank or the cotton dyed a fast black was woven together with the silk and
then the latter was dyed in the piece. If for example direct (substantive) dyes be
employed for dyeing in a comparatively weak dye bath the prepared cotton dyes
very dark whilst the silk by reason of the small quantity of dye contained in the
bath remains quite light and can then be subsequently dyed in all shades.
By weaving together fast dyed warp threads or weft threads a variety of effects
can be produced; these effects also may be produced by weaving together prepared
and non-prepared cotton into stuffs velvets plushes ribbons etc.
This however entails the drawback that the vegetable fabric or vegetable fibres
in the fabric shrinks excessively so that this process could not heretofore be
utilized in practical work.
Now the present invention is as follows:-
The vegetable fibre-in the form of hanks or as a woven fabric-is subjected
(whilst tightly stretched) to the action of suitable acids and bases and (after the
re-action is completed) is washed whilst still under tension until the strong internal
If now the fibre be removed from the
stress present in the fibre has ceased.
stretching apparatus or released it can be further treated without fear of its
shrinking.
Or the vegetable fibres in the hank or as a woven fabric are prepared without
stretching so that they can shrink then whilst still wet with the lye they are
stretched to their original breadth and length and while thus stretched they are
washed as before.
As an alkaline lye we may advantageously employ a concentrated solution of
caustic potash or caustic soda of say 15-32° Beaume which has not any injurious
action in a cold state upon the strength of the silk and cotton fibres but which
rather increases their strength. As acid it is advantageous to employ strong
sulphuric acid of say 49.5°-55-5° Beaume but when this is used the process must
be effected with more care and in particular the acid must be washed out
thoroughly at once after a short period of action.
:
The reaction takes place in a very short time especially when the cotton has
been previously well deprived of fat and is treated whilst in a somewhat moist
condition.
The completion of the re-action is indicated by a parchment-like appearance of
the fibre or fabric.

page_text: The cotton fibre thus prepared can be mordanted and dyed with all or any of the
chemicals which are generally employed or suitable in this process for treating
cotton.
Prepared cotton draws about twice as much tannin from a mordanting bath of
the same strength as ordinary cotton does..
Shrinking of the vegetable fibre in this process is obviated in the following
manner:
In the case of woven fabrics where the warp consists of silk and the weft is of
cotton such can be treated after having been woven.
For this purpose the dry or wet fabrics are stretched out wide and in this state
are watered or sprinkled with the lye for example.
After the re-action has set in which as already stated may be perceived by the
parchmenty appearance the fabrics are sprinkled with water until the very great
tension that set in with the treatment with the lye has ceased. Then the fabrics
are released and are neutralized in a special bath. Fabrics treated in this manner
do not shrink any more.
When the process is to be applied to narrow firm-edged ribbons velvet ribbons
with satin backing or to velvets with cotton pile and the like where the fibre to be
prepared cannot be subjected to tension or only with great difficulty such are
prepared before being woven.
This is then done in the hank and under tension by means of suitable mechanical
appliances of any well known character for stretching. The preparing itself is
effected as herein before described.
Instead of stretching the vegetable fibres-either in the hank or as a woven
fabric before treating them with the lye they may be first treated with the lye
and then the shrunk materials whilst still wet with the lye may be stretched to
their original length (or width) by known mechanical appliances and then be
washed in the stretched state until the tension or stress of the fibres has ceased.
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 herein-described improvement in treating vegetable fibres for dyeing
purposes with alkaline lyes or with acids consisting in subjecting the vegetable
fibre (in the hank or as a woven fabric) for the purpose of preventing shrinking of
the fibre whilst firmly stretched to the action of the bases or acids and then
washing the fibre whilst still stretched until the internal stress or tension thereof
has ceased substantially as and for the purposes set forth.
2. The herein described improvement in treating vegetable fibres for dyeing
purposes with alkaline lyes or with acids consisting in subjecting without stretching
the vegetable fibre (in the hank or as a woven fabric) to the action of bases-or
acids and then whilst it is still wet with the lye and shrunken-stretching same
to its original length and breadth and thereafter washing same while stretched as
before substantially as and for the purposes set forth.
Dated this 26th day of September 1895.
TONGUE & BIRKBECK,
Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicants.