Improvements in Treating Paper and other Fabrics, and in the Preparation of Solutions for that Purpose, and the Obtainment of a Bye-product in the said Preparation.
Year: 1894

page_text: Date of Application, 10th Mar., 1894
Complete Specification Left, 28th Apr., 1894-Accepted, 9th Feb., 1895
PROVISIONAL SPECIFICATION.
Improvements in Treating Paper and other Fabrics, and in the
Preparation of Solutions for that Purpose, and the Obtainment of
a Bye-product in the said Preparation.
We ALFRED ELKANAH HEALEY of Willesden Paper and Canvas Works,
Willesden Junction in the County of Middlesex Manufacturer and JAMES
WILLIAMS of the same place Chemist do hereby declare the nature of this
invention to be as follows:-
This invention has for its object improvements in treating paper and other fabrics
and in the preparation of solutions for that purpose and the obtainment of a bye
product in the said preparation.
It is well known that the liquid prepared by dissolving copper in a watery
solution of ammonia in the presence of air has the property of dissolving cellulose,
and such a liquid has been extensively employed in treating and waterproofing
paper and fabrics such as canvas by the method usually known as the "Willesden
process."
We find that by the addition of a soluble chromate (such as chromate or bichro-
mate of potash soda or ammonia) to the solution of copper thus prepared a liquid is
obtained which is better suited for treating certain kinds of paper and textile fabrics
than the copper solution without such addition. A more brightly tinted product
and greater durability of colour are obtained and fabrics thus treated can be more
readily dyed, the oxidising action of the chromate on the cellulose enabling it to
take up and retain more permanently certain colouring matters.
After dipping fabrics in the solution we prefer to pass them through hot or
boiling water partly to wash out any soluble matters present and partly to improve
the water resisting qualities of the fabric when subsequently dried. When the
fabrics are to be dyed, the colouring matters to be employed may in many cases be
conveniently dissolved in the boiling water used for this operation.
We further find that we can prepare an equally effective fluid in an economical
way (without the presence of air to oxidise metallic copper) by the employment of
chromate of aminonia or other chromium compound which will give rise to chromate
of ammonia when in contact with free ammonia such as chromic acid, or bichromate of
potash or of soda or of ammonia. For this purpose we prefer to use bichromate
of potash. We add to fragments of clean copper (preferably sheet copper)
bichromate of potash in quantity equal to about 3 times the weight of the copper
required to be dissolved. These materials are placed in a closed vessel capable of
revolving or supplied with an agitator. Aqueous ammonia solution is then run
into the vessel of strength varying from 8 to 15 per cent. After digestion and
agitation for a period sufficient to obtain the required amount of copper in solution
(the oxygen necessary for such solution having been furnished at the expense of
the chromate of ammonia originally present) together with precipitation of an
equivalent amount of hydrated oxide of chromium, the liquor is run off into a settling
tank. After the precipitate has fully settled the clear liquor forms the new solution
for the purposes described. The precipitate is then washed with successive
quantities of weaker ammonia and finally with water and utilised as a pigment, or
otherwise, the washings are mixed with strong ammonia solution and employed in
the preparation of a fresh batch of liquor.

page_text: The quantity of soluble chromate contained in the copper solution thus prepared
varies according to the amount originally employed relatively to the copper dissolved
being the excess present over and above that which has furnished oxygen to the
copper thereby becoming reduced to sesquioxide of chromium.
Instead of treating fabrics with a mixed solution containing simultaneously
cupra-ammonia and a soluble chromate, we find that in certain cases the same result
may be brought about by first treating the fabrics with cupra-ammonia solution as
in the ordinary process of preparing "Willesden" goods and then subsequently
passing them through a bath containing a solution of a suitable chromate. Or the
goods may be first passed through the bath of soluble chromate, dried, and
subsequently treated with cupra-ammonia solution.
Dated this 10th day of March 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
UUMI LUI DIEVITICATION.
Improvements in Treating Paper and other Fabrics, and in the
Preparation of Solutions for that Purpose, and the Obtainment of
a Bye-product in the said Preparation.
We, ALFRED ELKANAH HEALEY of Willesden Paper and Canvas Works,
Willesden Junction, in the County of Middlesex, Manufacturer, and JAMES
WILLIAMS, of the same place, Chemist, 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 treating paper and other fabrics
and in the preparation of solutions for that purpose and the obtainment of a bye-
product in the said preparation.
It is well known that the liquid prepared by dissolving copper in a watery solution
of ammonia in the presence of air has the property of dissolving cellulose and such
a liquid has been extensively employed in treating and waterproofing paper and
fabrics such as canvas by the method usually known as the "Willesden process."
According to this invention it has been found that by the addition to the solution
of copper thus obtained of a soluble chromate (such as chromate or bichromate of
potash soda or ammonia) a liquid is obtained which is better suited for treating
paper and textile fabrics than is the copper solution without such addition.
A more brightly tinted product and greater durability of colour are obtained
and paper or fabrics thus treated can be more readily dyed, the oxidizing action of
the chromate on the cellulose enabling it to take up and retain more permanently
certain colouring matters.
After dipping the paper or fabric in the solution and passing through squeezing
rollers and drying, it is sometimes preferred to pass the said paper or fabric through
water preferably hot to wash out any soluble matters present.
When the paper or fabric is to be dyed the colouring matters to be employed
may in many cases be conveniently dissolved in the water used for this operation.
An effective fluid can be prepared in an economical way (without the presence of
air to oxidize metallic copper) by the employment, in conjunction with ammonia
solution and copper, of chromate of ammonia or other chromium compound which
will give rise to chromate of ammonia when in contact with free ammonia and
preferably of bichromate of potash or of soda. The following is a convenient way
of performing this :-There is added to fragments of clean copper (preferably sheet
copper) contained in a drum or vessel of suitable material (such as iron for instance)
bichromate of potash in weight equal to about three times the weight of the copper

page_text: .
required to be dissolved. Aqueous ammonia solution of a strength varying from
eight to fifteen per cent. is then run into the drum or vessel. The drum or vessel is
preferably closable and capable of being rotated or of the contents being agitated
in any other convenient way. After digestion and agitation for a period of from
two to twelve hours (according to extent of agitation strength of ammonia and
proportion of bichromate) sufficient to obtain the required amount of copper in
solution (the oxygen necessary for such solution having been furnished at the expense
of the chromate of ammonia originally present) together with precipitation of an
equivalent amount of hydrated oxide of chromium the liquor is run off into a settling
tank. After the precipitate has fully settled the clear liquor forms the new solution
for the purposes described and can be run off for use." The precipitate is then
washed with successive quantities of weak ammonia liquor and finally with water
and filtered pressed and dried and may be utilized as a pigment or otherwise. The
washings can be mixed with strong liquor ammonia and employed in the preparation
of a fresh quantity of the solution as aforesaid.
The quantity of soluble chromate contained in the copper solution, prepared as
aforesaid, varies according to the amount originally employed relatively to the
copper dissolved, being the excess present over and above that which has furnished
oxygen to the copper thereby becoming reduced to sesqui-oxide of chromium.
The paper or fabric is treated as usual in the ordinary Willesden process that is
it is dipped in the said solution and passed between squeezing rollers and dried.
If required to wash out soluble matters it can then be soaked in hot water and again
dried when it possesses a more or less bright green colour. If other colour be
required the paper or fabric can be treated with a solution of colouring matter
instead of with water.
Instead of treating fabrics with a mixed solution containing simultaneously
cupra-ammonia and a soluble chromate it is preferred in some cases to treat the
paper or fabric with cupra-ammonia solution as in the ordinary process of preparing
"Willesden" goods and either before or after that treatment passing the said paper
or fabric through a bath containing a hot or boiling solution of the suitable
chromate.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The treatment of paper, or other fabric, with a compound solution containing
cupra-ammonia and a soluble chromate, for the purposes hereinbefore described.
2. The preparation of a solution, suitable for treating paper, or other fabric, by
dissolving copper in ammonia liquor with the addition of bichromate of potash, suda
or ammonia or any chromium compound which will give rise to chromate of ammonia
when in contact with free ammonia, substantially as hereinbefore described.
3. A solution suitable for treating paper, or other fabric, the said solution having
been prepared by the use of or containing, copper ammonia, and a soluble chromate,
substantially as hereinbefore described.
4. The treatment of paper, or other fabric, first with cupra-ammonium solution,
and afterwards with a soluble chromate, or vice versa, substantially as herein-
before described.
5. The bye-product or pigment produced as aforesaid in the preparation of a
solution such as is hereinbefore described.
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JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.