Improvements in and connected with the Production of Coloured Discharge Patterns on Indigo-dyed Cotton Fabrics in Calico, Printing.
Year: 1897

page_text: Date of Application, 1st Feb., 1897
Complete Specification Left, 1st Nov., 1897-Accepted, 4th Dec., 1897
PROVISIONAL SPECIFICATION.
Improvements in and connected with the Production of Coloured
Discharge Patterns on Indigo-dyed Cotton Fabrics in Calico,
Printing.
WILLIAM WATSON, of 60, George-street, Manchester, in the County of Lancaster,
Calico Printer, and ERNEST BENTZ, of The Royal Technical Institute, Salford, in the
County of Lancaster, Technical Chemist, do hereby declare the nature of this
invention to be as follows:-
This invention relates to the production in calico printing of patterns on
indigo-dyed cotton fabrics, and it has for its object the production of coloured
discharge-patterns in a better and more economical manner than heretofore.
The said invention consists substantially in preparing indigo-dyed cotton fabrics
with beta-naphthol and printing upon them diazotised solutions of paranitraniline,
metanitraniline, orthonitroparaphenetidine, alphanaphthylamine and of certain
other aromatic amines, suitably thickened for calico printing and mixed with a
soluble lead salt, drying the printed fabrics, and then converting the lead salt into
lead chromate and afterwards passing the fabrics into an acid bath in order to cause
the chromic acid of the lead chromate to be liberated and so destroy the indigo in
the printed parts of the fabrics.
To produce a pattern in red on a blue ground, for example, we pad the indigo-dyed
fabric with an alkaline solution of beta-naphthol, dry it, and print it with a suitably
thickened solution of diazoparanitrobenzene nitrate, obtained by diazotising
par anitraniline with sodium nitrite and nitric acid or by any other known method, to
which solution or mixture lead acetate or a mixture of lead acetate and lead nitrate
is further added. We then pass the printed fabric into a solution of potassium,
sodium or ammonium chromate, or a mixture of any or all of such salts, and, after
washing in water, pass it into a bath of sulphuric and oxalic acids at a temperature
of from 150 to 200 degrees Fahrenheit. The fabric is then rinsed in water and dried.
In an alternative method, instead of treating the printed fabric with alkali chromate
as herein before described, we first treat it with sodium, potassium or ammonium
carbonate, silicate, phosphate, arsenate or sulphate and then with potassium, sodium
or ammonium dichromate and then, after washing, treat it with a mixture of sulphuric
and oxalic acids.
Again in the methods herein before described we may dry the fabric after converting
the lead into lead chromate and after washing, before passing the fabric into the
bath of sulphuric and oxalic acids.
day of Tonuary 1907
WILLIAM WATSON..
ERNEST BENTZ.

page_text: Improvements in and connected with the Production of Coloured
Discharge Patterns on Indigo-dyed Cotton Fabrics in Calico
Printing.
We, WILLIAM WATSON of 60, George Street, Manchester, in the County of
Lancaster, Calico Printer, and ERNEST BENTZ, of 5, Demesne Road, Whalley Range,
Manchester, in the County of Lancaster (formerly of the Royal Technical Institute,
Salford) Printworks 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 relates to the production in calico printing of patterns on indigo
dyed cotton fabrics, and it has for its object the production of coloured discharge
patterns in a better and more economical manner than heretofore.
The said invention consists substantially in preparing indigo dyed cotton fabrics
with beta-naphthol and printing upon them diazotised solutions of paranitraniline,
metanitraniline, orthonitroparaphenetidine, and alpha-naphthylamine, suitably
thickened for calico printing and mixed with a soluble lead salt, drying the printed
fabrics and converting the lead salt into lead chromate and afterwards passing the
fabrics into a suitable acid bath, in order to cause the chromic acid of the lead
chromate to the liberated, and so destroy the indigo in the printed parts of the
fabrics.
To produce a pattern in red on a blue ground, for example, we pad the indigo dyed
fabric with an alkaline solution of beta-naphthol, dry it and print upon it a suitably
thickened solution of diazoparauitrobenzene nitrate, prepared by diazotising
paranitraniline with sodium nitrite and nitric acid, or by any other known method,
to which solution or mixture lead acetate or a mixture of lead acetate and lead nitrate
is further added. We then pass the printed fabric into a solution of potassium or
sodium chromate, or a mixture of both of these salts, and after washing it in water,
we pass it into a bath of sulphuric and oxalic acids at a temperature of 150
to 200 degrees Fahrenheit. The fabric is then rinsed in water, and dried, or
otherwise treated as may be desired.
Thus, according to the method hereinbefore described, we pad the indigo dyed
cotton fabric in a solution prepared by dissolving, for instance, 6 ounces by weight of
beta-naphthol by means of 5 fluid ounces of caustic soda solution of a density of 70
degrees Twaddell, in 1 gallon of water to which 1 gill of castor oil soap or Turkey-red
oil (containing 25 per cent. of fatty acid) is added, we then dry the fabric and print
upon it a printing mixture prepared by heating together until sufficiently thick for
calico printing
1 gallon of water,
8 lb. of lead acetate.

page_text: fabric again in water, or if it be desired to remove the lead sulphate or oxalate from
it, we treat the fabric with hot dilute hydrochloric or hydrofluoric acid.
In an alternative method, we effect the discharge of the indigo by employing
a mixture of hydrochloric and oxalic acids, or of hydrofluoric and oxalic acids, or of
hydrochloric, hydrofluoric and oxalic acids. In this case, we use 1 gill of concentrated
hydrochloric or hydrofluoric acid or of a mixture of both acids, with 4 ounces of
oxalic acid, per gallon of water, at a temperature of about 200 degrees Fahrenheit.
In another alternative method, instead of treating the printed fabric with potassium
or sodium chromate as hereinbefore described, we first treat it with sodium or
potassium carbonate and then with potassium or sodium dichromate, and then, after
washing the fabric, we treat it with a mixture of sulphuric and oxalic acids, or of
hydrochloric and oxalic acids, or of hydrofluoric and oxalic acids, as hereinbefore
described. We obtain suitable baths for this alternative process by dissolving
8 ounces of sodium carbonate in 1 gallon of water at the ordinary temperature, and
by dissolving 4 ounces of sodium dichromate in 1 gallon of water at a temperature
of from 120 to 160 degrees Fahrenheit, and so using them.
Again in the methods hereinbefore described we may dry the fabric after
converting the lead into lead chromate and after washing, before we pass the fabric
into the acid discharging bath.
The quantity of lead acetate given above refers to the printing of fabrics dyed
a dark shade of indigo: for medium and pale shades of indigo a smaller proportion of
lead acetate than that herein given, will suffice.
To produce coloured discharge patterns by the use of metanitraniline, orthonitro-
paraphenetidine, and alpha-naphthylamine, these bases are substituted for the
paranitraniline in the example herein before given, in the proportion of 138 parts of
metanitraniline, 158 parts of orthonitroparaphenetidine, and 143 parts of alpha-
naphthylamine to 138 parts of paranitraniline.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed we would have it
understood that we do not confine ourselves to the particular proportions or
strengths of the materials employed. as described herein but declare that what we
claim is
Producing coloured discharge patterns on indigo dyed cotton fabrics in calico
printing, substantially as described.
D
011 1
1.
1001
WILLIAM WATSON.
ERNEST BENTZ.