Improved Treatment of Textile Fabrics for Stiffening same, and Production of Material suitable for Use as Tracing Cloth.
Year: 1893

page_text: Date of Application, 5th Sept., 1893
Complete Specification Left, 5th June, 1894-Accepted, 7th July, 1894
PROVISIONAL SPECIFICATION.
Improved Treatment of Textile Fabrics for Stiffening same, and
Production of Material suitable for Use as Tracing Cloth.
I, EDWIN JOHN GOODWIN, of Stakehill Works, Castleton, near Manchester,
in the County of Lancaster, Agent, do hereby declare the nature of this invention
to be as follows:-
This invention has reference to the treatment of textile fabrics for stiffening
same and production of material suitable for use as tracing cloth.
•
In the Specification of a former application for Letters Patent filed by me,
No. 22566, dated 8 December 1892, I have described the manufacture of sheet
material specially suitable for use as label cloth and book binders' cloth by saturating
textile fabric or cloth having a close texture and composed of vegetable fibres with
dilute sulphuric acid having a specific gravity of 115 degrees Twaddle or thereabout
(whilst at a temperature of from 64 to 65 degrees Fabt.) and after treatment of the
fabric or cloth for removal of sulphuric acid, subjecting the treated fabric or cloth
to pressure between rolls, such as calendering rolls to impart to it the desired
finished appearance and complete the closing of the pores or interstices.
Now I have discovered since the date of my said first Application that by the
process referred to with certain modifications hereinafter described vegetable
textile fabrics having an open nature such as lace goods can have imparted to them
a stiffness and finish that renders them suitable for use after washing and drying
without the application as heretofore usual of a stiffening or dressing agent such as
starch.
For this purpose I saturate the fabric in a bath of dilute sulphuric acid having
a specific gravity of from 115 to 117 degrees Twaddle at a temperature of from 64
to 65 degrees Faht., and after removing excess of free sulphuric acid by passing
between squeezing rollers, washing with water, neutralizing in a weak alkaline bath
and drying, I subject the treated fabric to pressure between rolls such as calendering
rolls as described in my former Specification with reference to the treatment of
vegetable textile fabrics or cloth having a close texture.
I have also discovered that sheet material of a transparent or translucent
character suitable for use as a substitute for ordinary tracing cloth (which it closely
resembles) can be produced by treating a finely woven cloth such as lawn, muslin,
jaconet, or the like in the same manner, but using a bath of dilute sulphuric acid
having a specific gravity of from 128 to 132 degrees Twaddle at a temperature
that may vary from 64 to 72 degrees Faht.
The finely woven cloth is passed through the bath of dilute sulphuric acid so as
to be saturated thereby; then squeezed between rollers by which much of the
sulphuric acid is removed; then washed and subjected to treatment with alkaline
solution to neutralize remaining acid; dried, and passed between calendering or
finishing rolls. The cloth is subjected to the action of the dilute sulphuric acid
for a short time only, about 3 or 4 seconds being usually sufficient from the time it
enters the acid bath to the time it passes between the squeezing rollers.
Dated this 4th day of September 1893.

page_text: COMPLETE SPECIFICATION
Improved Treatment of Textile Fabrics for Stiffening same, and
Production of Material suitable for Use as Tracing Cloth.
I, EDWIN JOHN GOODWIN, of Stakehill Works, Castleton, near Manchester,
in the County of Lancaster, Agent, 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 reference to the treatment of textile fabrics for stiffening same
and production of material suitable for use as tracing cloth.
In the Specification of a former application for Letters Patent filed by me,
No. 22566, dated 8 December 1892, I have described the manufacture of sheet
material specially suitable for use as label cloth and book-binders' cloth by
saturating textile fabric or cloth having a close texture and composed of
vegetable fibres with dilute sulphuric acid having a specific gravity of 115 degrees
Twaddle or thereabout and after treatment of the fabric or cloth for removal of
sulphuric acid, subjecting the treated fabric or cloth to pressure between rolls, such
as calendering rolls to impart to it the desired finished appearance and complete
the closing of the pores or interstices.
Now I have discovered since the date of my said first Application that by the
process referred to, with certain modifications hereinafter described, vegetable
textile fabrics having an open nature such as lace goods, can have imparted to them
a stiffness and finish that renders them suitable for use after washing and drying,
without the application as heretofore usual of a stiffening or dressing agent such as
starch.
For this purpose I saturate the fabric in a bath of dilute sulphuric acid having a
specific gravity of from 115 to 117 degrees Twaddle at a temperature of from 54
to 65 degrees Faht., and after removing excess of free sulphuric acid by passing
between squeezing rollers, washing with water, neutralizing in a weak alkaline bath
and drying, I subject the treated fabric to pressure between rolls such as calendering
rolls as described in my former Specification with reference to the treatment of
vegetable textile fabrics or cloth having a close texture.
And in order that my invention may be fully understood I will now describe
with reference to the accompanying illustrative drawings the best way known to me
of carrying it into practical effect.
In the said drawings,
Fig. 1 is a longitudinal section; and
Fig. 2 a plan illustrating diagrammatically, apparatus suitable for carrying out
.my invention, but which apparatus is not claimed.
1 is a lead-lined vessel containing a bath 2 of dilute sulphuric acid prepared as
hereinafter described. In the bath is immersed a guide bar or roller 3 formed of
suitable material such as wood, or wood covered with lead, under which the
vegetable textile fabric. 4 of the kind mentioned is drawn. 5 is a roller over
which the fabric, after leaving the bath, is led into a washing vessel 6 for the
purpose of removing as completely as practicable the free sulphuric acid from the
fabric. This washing vessel in the example shown, is provided with a series of
guide rollers 7 over and under which the fabric is drawn so that the excess of
sulphuric acid is washed out by streams of water discharged over the upper and
lower surfaces of the fabric from perforated pipes 8 8ª respectively. These pipes
are a ranged longitudinally of the vessel above and below the guide rollers 7 and
near the ends thereof as shown. With a view of reducing the quantity of washing
water that would otherwise be necessary to remove the last traces of free sulphuric
acid from the treated fabric, it is advantageous to pass the said fabric through a
bath consisting of a very weak solution of an alkali, for example caustic alkali, or

page_text: ammonia which will neutralize the said traces of free acid and form therewith au
alkaline salt that will be washed out of the fabric as it passes through the said
bath. This bath should be tested from time to time by suitable means such as
litmus paper to ascertain that it is slightly alkaline, fresh alkali being added
thereto from time to time, as occasion may require. A suitable construction of
neutralizing apparatus is shown in the accompanying drawings and comprises a
vessel 9 provided with a series of rollers 10 immersed in the alkaline bath 11 and
so arranged that the fabric, which is led direct from the washing vessel 6 between:
squeezing and guiding rollers 12 and 12, passes through the said bath in a zig-zag
manner whence it is led (with or without a final washing in water) to the drying
cylinders and calendering rolls. The excess of acid may be neutralized by leading
the treated fabric direct into an alkaline bath and then washing to remove the
alkaline salt thereby formed, but this method of removing the excess of free
sulphuric acid is not so advantageous as the method previously described on
account of the greater cost and difficulty of working. The fabric after being thus.
free from sulphuric acid, is dried by being led over and under drying cylinders as
well understood and is then passed between calendering rolls whereby the desired
finished appearance is imparted to the material. The drying cylinders and
calendering rolls may be of the ordinary construction, employed in the manner.
usually followed in drying and calendering textile fabric, and will therefore be
readily understood without further description. If the fabric is to be dyed, it is
led through a dye batb after removal of the sulphuric acid, and before passing over
the drying cylinders.
In order that the sulphuric acid shall not be rapidly carried over from the acid
vessel 1 to the washing vessel 6 by the fabric, and thereby wasted, and also to
enable the washing of the treated fabric to be effected with as small a quantity of
water as practicable, I use in conjunction with the roller 5, a second similar
roller 5, and so arrange these rollers that the treated fabric in passing between
them, will be subjected to considerable pressure so that the greater portion of the
free sulphuric acid will be squeezed out and returned to the vessel 1 for re-use. In.
this way I also obviate injurious heating of the treated fabric, such as would be
liable to occur, if it were passed, whilst saturated with acid, into a washing vessel
.such as described, using a comparatively small quantity of washing water.
When
a pair of rollers 5 5ª is used as described, one of such rollers is driven by suitable
means such as a belt, so as to draw the fabric through the bath at the required rate..
Similarly driven squeezing rollers fixed at the out-going end of each washing or
neutralizing vessel as shown then serve to draw the fabric from the squeezing
rollers 55 through the washing and neutralizing vessels and supply it to the drying
cylinders. This bath is prepared by adding sulphuric acid to water in such a
proportion that the resulting dilute sulphuric acid will have a specific gravity
of from about 115 to 117 degrees Twaddle when at a temperature of from
54 to 65 degrees Faht. at about which temperature it is used for treating the
fabric in the manner described, and whereby the fibres of which the fabric is
composed, are partly converted into a parchment-like state. The fabric to be
treated should be in a pure condition, that is to say, without any dressing or other
impurities. It should be scoured and then thoroughly dried in which state it should
be fed into the bath of sulphuric acid so as to obviate heating of the said fabric,
and consequent injury to the resulting product, such as would ensue if the fabric
were fed into the bath of dilute sulphuric acid in a wet or damp state. To ensure
that the fabric shall be completely saturated with the dilute sulphuric acid, the
roller 3 under which it is drawn may advantageously be so arranged that its bottom.
portion will be about 8 or 10 inches below the level of the bath.
The time during which the fabric is to be subjected to the converting action of
the dilute sulphuric acid, that is to say from the moment it enters the bath to the
moment it passes between the rolls 5, 5" will vary from about three to fifteen
seconds, according to the nature of the fabric and its consequent ability to absorb
the said acid; the thicker the fabric the longer must it be subjected to the action

page_text: of the sulphuric acid. When treating light fabrics, such as muslin goods, three
seconds will usually be sufficient, whilst for heavier fabrics such as
about
seconds will usually be necessary to ensure a satisfactory result.
Textile fabric stiffened and finished as described has no objectionable smell, is not
liable to undergo chemical change by exposure in a moist atmosphere, and does not
lose its stiffness when dried after being wetted.
I have also discovered that sheet material of a transparent or translucent
character suitable for use as a substitute for ordinary tracing cloth (which it closely
resembles) can be produced by treating a finely woven cloth such as lawn, muslin,
jaconet, or the like in the manner and by the means hereinbefore described with
reference to and shown in the accompanying drawings, but using a bath of dilute
sulphuric acid having a specific gravity of from 128 to 132 degrees Twaddle at a
temperature that may vary from 64 to 72 degrees Faht.
The cloth in this case is subjected to the action of the dilute sulphuric acid for a
short time only, about 3 or 4 seconds being usually sufficient from the time it enters
the acid bath to the time it passes between the squeezing rollers.
In this case the passage of the treated cloth, when dried, between the calendering
rolls, not only imparts the desired finished appearance to the cloth but also
completes the closing of the pores or interstices therein.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The hereinabove described improved treatment of vegetable textile fabrics
having an open nature such as lace goods, consisting in saturating the same with
dilute sulphuric acid having a specific gravity of 115 to 117 degrees Twaddle or
thereabout, whilst at a temperature of about 54° to 65° Fahr., and after treatment
of the fabric for removal of sulphuric acid and moisture, subjecting the treated
fabric to pressure between rolls such as calendering rolls, whereby such fabrics
have imparted to them a stiffness and finish that renders them suitable for use,
after washing and drying without the application as heretofore usual of a stiffening
or dressing agent.
2. The manufacture or production of sheet material suitable for use as tracing
cloth by saturating a finely woven cloth such as lawn, muslin, jaconet or the like,
with dilute sulphuric acid having a specific gravity of from about 128 to 132 degrees
Twaddle at a temperature of from about 64 to 72 degrees Fahr. and after treatment
of the cloth for removal of sulphuric acid and moisture, subjecting the cloth to
pressure between rolls such as calendering rolls to impart to it the desired finished
appearance and complete the closing of the pores or interstices therein.
3. The hereinabove described improved manufacture of sheet material specially
suitable for use as tracing cloth.