Improvements in the Manufacture of Ornamental Fabrics.
Year: 1888

page_text: Date of Application, 28th Nov., 188 -Accepted, 20th July, 1889
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Ornamental Fabrics.
I FREDERIC HUNGERFORD BOWMAN of Halifax in the West Riding of the County
of York Cotton Spinner 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 relates to that class of woven knitted or lace fabrics principally com-
posed of wool or silk or a mixture of wool and silk, but into which during the process
of weaving or manufacture certain threads of cotton or linen or other vegetable fibre
are introduced called "iraw-threads " or "drag-threads" for the purpose of forming
peculiarities in the pattern.
These draw-threads" not being required to appear in the finished article have
hitherto been removed from the fabric either by hand or by mechanical means, a
tedious and expensive operation.
But by the use of my invention they will be removed in a much more simple and
economical manner by chemical means as hereinafter described.
For the purposes of my invention I take a piece of the woven knitted or lace material
with the cotton or other vegetable "draw threads therein as above mentioned, and
place the said fabric in a bath of dilute sulphuric acid, (the ordinary sulphuric acid of
commerce diluted with about ten times its volume of water I have found to be the
best for the purpose when sulphuric acid is used, but it will do much weaker if a
longer time is taken in the process) until the whole of the cotton or linen "draw-
threads are completely saturated with the acid solution.
"
The solution is best used cold although when tepid or about sixty degrees
(Fahrenheit) it seems to absorb into the cotton or linen best. About ten minutes
immersion is usually sufficient but the time may be varied with the texture and
thickness of the cotton or other threads.
The fabric is then removed from the acid bath and after all superflous moisture is
removed by wringing passing through rollers or any suitable process, the fabric is
slowly dried in a drying temperature not exceeding one hundred degrees (Fahrenheit).
I then place the fabric in a closed chamber uniformly heated by steam hot air or
any other suitable means care being taken that the temperature is not too high. I
have found that a temperature of two hundred degrees (Fahrenheit) works very well
in ordinary cases.
The heat is to be applied until the whole of the cotton or linen fibre just changes
color in consequence of the carbonization of the same so that the fibre is then reduced
to a disintegrated condition.
The fabric is then removed and subjected to a blast of air or a jet or spray, of water
or dry steam, or the fabric may be placed between two pieces of thick cloth or other
material or wrapped up in the cloth so as to preserve the reticulated fabric of silk
woollen or similar fibre and beaten until the whole of the carbonized cotton or linen
draw threads are removed in the form of fine dust leaving the silk or other ornamental
fabric in the form required.
This process when the wrapper is used is
removal of the fabric from the wrapper and by
otherwise which assists the removal of the dust.
dust from coming freely into the place where the
It should be removed by artificial currents or
being whaled by any operator.
materially assisted by a frequent
shaking the fabric either by hand or
Care should be taken to prevent the
operation is carried on.
otherwise so as to prevent it from
The silk, woollen or other fabric is next cleansed by washing with water either with
or without the addition of a small quantity of alkali so as to remove all traces of acid

page_text: after which the fabric is ready for drying and finishing, or it may be dyed or bleached
and stiffened and finished in any suitable manner.
It is obvious that in some cases a stronger or weaker acid may be used for acting
on the cotton or linen fibre, and a higher or lower temperature may be employed in
the above processes of drying and heating according to the character of the fabric
operated upon and the results which it is desired to produce.
These variations will be readily made as required by an operator of experience.
In some cases the operations above referred to for drying and carbonizing may be
carried on in the same chamber, the temperature being raised as required.
Where the cotton or linen draw threads are strong and the silk woollen or other
fabric has to be dyed in dark colors I have found the usual sulphuric acid most
advantageous but I do not confine my invention to the use of such acid as other acids
which are known to act upon cotton or linen in a similar manner may be employed.
Again some salts such as aluminium or zinc chloride or other salts which as
chemists would know give off acids by decomposition may be used for acting upon
the cotton or linen. Again mixtures of these agents may in some cases be employed
and where their action is too energetic they should be diluted as required to suit the
nature of the fabric operated upon, regard being had in all cases to the action of the
degree of heat which may be used to produce the required results.
'
Where color is an object and any remains of carbonized cotton or linen would be
objectionable use chlorine or hydrochloric acid either in a closed chamber as a dilute
gas or in solution.
For the solution I use the ordinary hydrochloric acid of commerce about thirty two
degrees (Twaddle) diluted with about ten times its volume of water and proceed exactly
in the same way as described above with the dilute sulphuric acid except that I with-
draw the fabric from the final heating chamber as soon as the cotton or linen fibre
is sufficiently acted upon to be reduced (when rubbed between the fingers) into a fine
white powder, which may be ascertaine by removing a small piece of the same from
time to time and testing, or it is usually indicated by a slight change to a greyish
white tinge.
The use of hydrochloric acid in the form of a gas can only be safely employed when
the fabric is thick in the figured part and in such case the fabric should be previously
soaked in water. As a rule the solution answers best for all light fabrics.
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 :-
The manufacture of ornamental fabrics of silk, wool, or other similar animal fibres
or mixtures of the same by weaving such silk wool or animal fibre together with
"draw-threads" of cotton or linen or other vegetable fibre and then removing the
said draw threads by treating the fabric with acid or gas followed by the action of heat
substantially in the manner and for the purposes herein described.
Dated this 27th day of November 1888.
GEORGE
DAVIES,
4, St. Ann's Square, Manchester, Agent for the Applicant.