Improvements in Dyeing with Vidal Black and Colours of the same Group.
Year: 1898

page_text: Date of Application, ɔth Apr., 1898
Complete Specification Left. 23rd Dec., 1898-Accepted, 11th Feb.,
1899.
Date of Application, ɔth Apr., 1898
Complete Specification Left. 23rd Dec., 1898-Accepted, 11th Feb., 1899...
PROVISIONAL SPECIFICATION.
Improvements in Dyeing with Vidal Black and Colours of the same
Group.
I, EWALD HÖLKEN, of Barmen, Germany, Chemist, do hereby declare the nature
of this invention to be as follows:-
"Vidal black
.bs
Hitherto dyeing with what is known as
has proved defective
owing to want of uniformity and the appearance of reddish stains and blotches
also the brown sometimes greenish colour of the dyed material.
The reddish stains and blotches are due to products of oxidation at the places
of the material which are exposed to air during the dyeing these after cooling on
the fibre becoming permanent and incapable of being removed chemically or
otherwise.
'
My present invention relates to a process whereby a pure uniform black dye is
obtained. For this purpose the skeins are taken out in small quantities such as
one kilogram at a time and are wrung several times quickly, thus squeezing out
the boiling liquid which carries with it such oxides as may have been formed; the
twisting also having the effect of spreading the dye uniformly. In this way a
quite uniform black dye without stains or blotches is obtained."
For developing a bluish black the known process is objectionable as the result
is generally a dirty brownish or greenish dye, because it has not been sufficiently
oxidised.
According to my invention, for dyeing bluish black the cotton receives com-
plementary treatment after the known treatment with the bath of potassium bi-
chromate and sulphuric acid, instead of which sodium bichromate and sulphuric
acid are employed, or other suitable oxidising agents such as potassium or sodium
chlorate, animonium vanadate or the like. After eliminating the acid by successive
washings the cotton is subjected to supplementary oxidation in moist air at a
temperature of 40° to 60° C. for 6 to 12 hours. After this treatment the dye
becomes fully developed in the soap bath slightly acidulated with acetic acid, as
a beautiful deep bluish black, quite fast to acids, alkalies, light and air.
Dated this 5th day of April 1898.
ABEL & IMRAY,
Agents for the Applicant.
1
COMPLETE SPECIFICATION.
Improvements in Dyeing with Vidal Black and Colours of the same
Group.
I, EWALD HÖLKEN, of Barmen, Germany, 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:
Hitherto dreing with what is known as "Vidal black" has proved defective

page_text: owing to want of uniformity and the appearance of reddish stains and blotches
also of the brown sometimes greenish colour of the dyed material.
The reddish stains and blotches are due to products of oxidation at the places
of the material which are exposed to air during the dyeing, these after cooling on
the fibre becoming permanent and incapable of being removed chemically or
otherwise.
My present invention relates to a process whereby a pure uniform black dye is
obtained. For this purpose the skeins are taken out in small quantities such as
one kilogram at a time and are wrung several times qu
quickly, thus squeezing out
the boiling liquid which carries with it such oxides as may have been formed; the
twisting also having the effect of spreading the dye uniformly. In this way a
quite uniform black dye without stains or blotches is obtained."
For developing a bluish black the known process is objectionable as the result
is generally a dirty brownish or greenish dye, because it has not been- sufficiently
oxidised.
►
1
According to my invention, for dyeing bluish black the cotton receives com-
plementary treatment after the known treatment with the bath of potassium bi-
chromate and sulphuric acid, instead of which sodium bichromate and sulphuric
acid are employed, or other suitable oxidising agents such as potassium or sodium
chlorate, ammonium vanadate or the like. After eliminating the acid by successive
washings the cotton is subjected to supplementary oxidation in moist air at a
temperature of 40° to 60° C. for 6 to 12 hours. After this treatment the dye
becomes fully developed in the soap bath slightly acidulated with acetic acid, as
a beautiful deep bluish black, quite fast to acids, alkalies, light and air.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I declare that what I claim is:-
The herein described process of dyeing with Vidal black by wringing and
squeezing the dyed material so as to expel the liquid, then after treating the
material with chrome and freeing it from acid by frequent washing subjecting it
to oxidation for several hours in moist air at a temperature of 40° to 60° C.
before the soap bath for the purpose set forth.
Dated this 23rd day of December 1898.
ABEL & IMRAY,
Agents for the Applicant.