IMPROVEMENTS IN MORDANTS USED IN PRINTING AND DYEING
Year: 1855

page_text: LETTERS PATENT to Emile Kopp, of Accrington, in the County of
Lancaster, Chymist, for the Invention of "IMPROVEMENTS IN MORDANTS
USED IN PRINTING AND DYEING."
Sealed the 12th October 1855, and dated the 10th July 1855.
PROVISIONAL SPECIFICATION left by the said Emile Kopp at the Office
of the Commissioners of Patents, with his Petition, on the 10th July
1855.
I, EMILE KOPP, of Accrington, in the County of Lancaster, Chymist, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN MOR-
DANTS USED IN PRINTING AND DYEING" to be as follows:-
In preparing mordants it has hitherto been customary to use the acetates
of certain salts; now, my Invention consists in substituting in their stead
the hyposulfites of the same salts, or solutions made by acids or alkalis of
arseniates, or phosphates, or chromates of the same salts. I also prepare a
mordant with solutions of bismuth, containing nitric and acetic acids, and
use this mordant alone or combined with iron salts.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Emile Kopp in the Great Seal Patent Office on the 8th
January 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EMILE
Korr, of Accrington, in the County of Lancaster, Chymist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of July, in the year of our Lord One
thousand eight hundred and fifty-five, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Emile Kopp, Her special license that I, the said Emile Kopp, my
executors, administrators, and assigns, or such others as I, the said Emile
Kopp, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for IMPROVEMENTS IN MORDANTS USED
IN PRINTING AND DYEING," upon the condition (amongst others) that I, the
said Emile Kopp, by an instrument in writing under my hand and scal,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Emile Kopp, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
Specification thereof (that is to say):-
My said Invention of improvements in mordants used in printing and
dyeing, consists,―
First, in the preparation of mordants with hyposulfites instead of acctates.
Secondly, in the preparation of mordauts with solutions made by acids or
alkalies of arseniates, phosphates, and chromates, instead of acetates.
Thirdly, in the preparation of a mordant with solutions of bismuth con-
taining nitric and acetic acids, and in the use of this mordant alone or com
bined with iron salts.
And in order that my Invention may be fully understood and readily
carried into effect, I will proceed to describe the manner of performing the
same.

page_text: Firstly, the acetates, for which I substitute hyposulfites, are, the acetates of
potash, soda, lime, alumina, chrome, iron, and tin. The preparation of the
hyposulfites being well known by manufacturers and chemists, I have only to
observe, that the hyposulfites of potash, soda. and lime, like the corresponding
acetates, are no mordants by themselves, yet form mordants when mixed with
the ordinary salts of alumina, chrome, iron, and tin, by converting these salts
into hyposulfites. I prepare pure byposulfite of alumina by decomposing forty-
one pounds of ordinary sulphate of alumina or sixty pounds of alum with forty-
eight pounds of crystallised byposulfite of lime; sulphate of lime is precipitated,
and hyposulfite of alumina remains in solution, either alone or mixed with
a potash or ammonia salt, when alum has been used. In these operations
boiling must be avoided, the hyposulfite of alumina being decomposed with
disengagement of sulphurous acid by long continued ebullition. For this
reason I prefer generally to prepare the mordant of hyposulfite of alumina
by adding to a solution of sixty pounds of alum, or forty-one pounds of
sulphate of alumina, or the corresponding quantity of chloruret or nitrate of
alumina, forty-six pounds of crystallised byposulfite of soda, or thirty pounds
of the same salt perfectly dried; sulphate, chloruret, or nitrate of soda are
formed, and the hyposulphurous acid combines with the alumina. Instead of
decomposing the alum and other alumina salts completely by the byposulfites
of lime or soda, I have found it advantageous to add to the thickened solutions
of alumina salts such a quantity of hyposulfite of lime or soda, that only two-
thirds or three-fourths of the alumina salt (either alum, or sulphate, chloruret,
or nitrate of alumina,) may be decomposed; the pure hyposulfite of alumina,
I
like the pure acetate of alumina, being in many cases not a good mordant.
prepare in the following manner a cheap and good alumina mordant:-
A hot solution of alum or sulphate of alumina is decomposed with a clear
alkaline solution of chloruret of calcium (obtained in dissolving as much as
possible lime in the solution of chloruret of calcium) in such a quantity that
only two-thirds or three-fourths of the alum or the sulphate of alumina may
be decomposed. After cooling, the mixture is filtered, and the precipitate of
sulphate of lime is well pressed. The clear liquid, containing basic chloruret
of alumina, can now be thickened with gum, starch, or flour, in the manner
generally employed in thickening alumina mordants. When the thickened
paste has cooled down to about ninety degrees Fahrenheit, hyposulfite of soda
is added in such a quantity that again only two-thirds or three-fourths of the
hydrochloric and sulphuric acids combined with the alumina may be saturated
by the soda of the hyposulfite; the colour being well mixed is now ready for
use. The mordant after a certain time presents, especially at the surface, a

page_text: whitish milky appearance, and smells somewhat like sulphurous acid. The
colour may stand several days in a covered vessel without being spoiled, and it
is used exactly in the same manner as the ordinary alumina mordants. The
advantages are, its cheapness, and the quickness with which the alumina is
fixed upon the fibrous materials; it possesses the peculiar property to hinder
or impede the fixation of iron mordants as long as byposulfite of alumina
remains to be fixed. The preparation of the hyposulfite of chrome is very
similar to that of the hyposulfite of alumina. I decompose chrome, alum, or
sulphate of chrome by hyposulfite of lime, the soluble byposulfite of chrome
being separated by filtration and pressure from the precipitate of sulphate of
lime; or I add hyposulfite of soda to solutions, either thickened or not
thickened, of sulphate, chloruret, or nitrate of chrome. The hyposulfite of
chrome is a mordant much less stable than the hyposulfite of alumina, and
requires to be used a short time after its preparation. The mordant being
printed, the dessication fixes completely the oxide of chrome, and it is not
necessary to pass the fabrics through alkali. All heating of the hyposulfite of
chrome mordant before its application must be carefully avoided, and for this
reason, when thickening with starch is required, it must take place before the
addition of the alkaline byposulfite. All salts of peroxyde of iron in contact
with hyposulfites being immediately converted into salts of protoxyde of iron,
the hyposulfite of protoxide of iron exists alone. This reducing property of the
hyposulfites can be made useful in such printing and dyeing processes in
which it is necessary to reduce peroxyde of iron to the state of protoxyde, and
for which hitherto chloruret of tin has been principally employed. Hyposulfite of
protoxide of iron is prepared in decomposing crystallised sulphate of ironoxydul
by itsweight of crystallised hyposulfite of lime, or in adding simply byposulfite
of soda to a solution of a salt (sulphate, chloruret, acetate.) of protoxyde of
iron. The hyposulfite of iron is used exactly in the same manner as the
acetate of iron, commonly called iron liquor, in the printing and dyeing process.
When this mordant is used in combination with alumina mordants in order to
produce with madder or garancine chocolate colours, care must be taken to
have the fabrics impregnated or printed with the compound mordant, exposed
to the action of the air during a sufficient length of time (twenty-four to
thirty-six hours), because the oxyde of iron becomes oxydised and fixed only
after all the alumina has been combined with the fibrous material. I
prepare
the mordant of hyposulfite of tin by adding to cold solutions of proto or
per-chlorurct of tin previously thickened (when thickening is required), such a
quantity of hyposulfites of soda or line, that only one-third or one-half of the
tin salts may be decomposed by the alkaline hyposulfites. The heating of the

page_text: mordant must be avoided before its application upon the fabrics, because the
byposulfite of tin is very easily decomposed by heat in disengaging sulphurous
acid. For the same reason, it has been found advantageous not to dry too
quickly or too strongly the fabric impregnated with the new tin mordant. The
hyposulfite of tin being decomposed spontaneously after a certain time, it is
necessary to add the alkaline byposulfites to the tin salts only a short time
before the use of the mordant.
Having now described the manner of preparing and using the new hypo-
sulfite mordants, I have only to add, that the fixation of those mordants upon
the fabrics is obtained by drying only, and that the passing through cow-dung
bath, the cleaning, washing, and drying processes, are performed afterwards,
exactly in the same manner as when acetate mordants have been employed.
Secondly, the acetates for which I substitute solutions of the corresponding
arseniates, phosphates, or chromate, either in acids or in alkalis, are the
acetates of zinc, mangan, iron, alumina, chrome, copper, and tin. I prepare
first the insoluble arseniates of these metals by precipitating soluble salts of
zine, mangan, iron, alumina, chrome, copper, and tin with alkaline soluble
arseniates, especially arseniate of soda, taking care to maintain in the mixture
a slight alkaline reaction, and adding, if necessary, a small quantity of caustic
soda. The precipitates of insoluble arseniates are well washed, pressed, and
kept for use in a wet state. In the same manner I prepare the insoluble
phosphates, in substituting only for the alkaline arseniate phosphate of soda.
Having obtained the insoluble arseniates and phosphates, I prepare my acid
mordants in dissolving, with the assistance of a gentle beat, the arseniates of
zinc, mangan, alumina, chrome, copper, protoxyde and peroxyde of iron, and
of protoxyde of tin in as great a quantity as possible, in strong acids, and, by
preference, in a mixture of four parts of strong hydrochloric acid with one part
of nitric acid. I prepare my alkaline mordants in dissolving as much as
possible the arseniates and phosphates of zinc, copper, and peroxyde of iron in
strong liquid ammonia, and the arseniates and phosphates of zinc, alumina,
chrome, and tin, in caustic liquid potash or soda. When per-chloruret of tin
is not precipitated by phosphate or arseniate of soda, I use the mixture of
these salts. The only chromate whose use I have found advantageous is the
chromate of copper; I prepare it in precipitating a solution of a copper salt
with a solution of alkaline chromate of potash or soda. The precipitate, after
being well washed and pressed, is dissolved in strong liquid ammonia, forming a
beautiful green solution. In a few cases the solution of chromate of copper in
nitric acid can also be used as a mordant. Having obtained the acid and
alkaline solutions of arseniates, phosphates, and chromate in the manner above

page_text: described, I use them as mordants. When thickening is required, the alkaline
ammoniacal solutions are best thickened with gum, and in some cases with
leiocome. The alkaline potash or soda solutions are best thickened with
leiocome; the acid solutions can be thickened either with gum and leiocome,
or with starch and flour. In the latter case some precautions must be taken
to prevent the liquefaction of the paste, by the strong acid reaction of the
mordant, added to the influence of a high temperature. I have found advan-
tageous first to prepare the paste in thickening flour and starch only with
water at two hundred and twelve degrees Fahrenheit, to let the paste become
nearly cool, and to incorporate the strong and concentrated acid mordant in
The fixation of the
proportion to the required strength of the colour.
mordant after printing is obtained by drying and exposing to the action of the
air. When strong acid mordants are used, the drying process must not be
performed too quickly or too strongly, in order that the solidity of the fibrous
materials may not be injured. In the same case it will sometimes be found
useful to pass the fabrics, after the dessication and before the cow-dung bath,
through a weak alkaline or a chalk bath. After the application of these new
mordants upon the textile materials, the other parts of the printing and dyeing
process are performed exactly in the same manner as when ordinary mordants
have been employed. I have only to observe, that the mordants of zinc,
mangan, copper, and tin, when dyed with garancine, require that the tempera-
ture of the dyeing bath should not be raised above one hundred and cighty
degrees Fahrenheit, the colours being spoiled by ebullition. For the purples
or lilacs to be obtained with garancine, I prefer to use acid solutions of a
mixture of arseniates of protoxyde and peroxyde of iron, the latter a little in
excess; they will be found advantageous especially for the darker purple shades.
In dyeing the ammoniacal chromate of copper mordant with garancine, peculiar
brown crimson shades will be obtained, and in dyeing the same mordant with
sapan or logwood, fine colours, having a peculiar metallic appearance, can be
produced.
Thirdly, I prepare the mordant of aceto-nitrate of bismuth by dissolving as
much bismuth as possible in hot nitric acid diluted with half its weight of
water. In cooling, yellowish crystals are deposited; these crystals, dissolved in
acetic acid at eight degrees of Twaddle's hydrometer, constitute my improved
mordant. The solution can be mixed with water without being decomposed,
and without giving a white precipitate of subnitrate of bismuth. This mordant
is very easily thickened with gum or leiocome. When thickening with starch or
flour is required, the paste must first be made with acetic acid alone, more or
less diluted with water, and when the paste has completely cooled, the crystals

page_text: of bismuth salt are added and the colour well mixed. The thickened colour
can be kept for a long time without being spoiled or decomposed. The print-
ing of the mordant is performed in the ordinary manner, and the fixation takes
place by exposure to the air and drying. By using a very strong acid mordant
some precautions must be observed in drying to avoid injuring the fibrous
materials. The aceto-nitrate of bismuth mordant dyed with garancine pro-
duces peculiar bright crimson shades. In mixing this mordant thickened with
starch with a solution of arseniate of iron in nitric acid thickened with gum
(gum being used to prevent the precipitation of insoluble arseniate of bismuth)
in various proportions, and printing and dyeing in the ordinary manner with
garancine, dark crimson and purple crimson shades are obtained, which
cannot be produced with a mixture of the ordinary iron and alumina
mordants.
Having now described the nature of my Invention, and the manner in which
the same is to be performed, I declare that I claim as my Invention,-
First, the use of the hyposulfites instead of acetates for the preparation
of mordants.
Secondly, the use of acid or alkaline solutions of arseniates, phosphates, and
chromate, instead of acetates for the preparation of mordants.
And, thirdly, the use of aceto-nitrate of bisnuth, either alone or mixed with
iron salts, as mordants for garancine colours.
In witness whereof, I, the said Emile Kopp, have hereunto set my hand
and seal, this Second day of January, in the year of our Lord One
thousand eight hundred and fifty-six.
EMILE NOPP. (L.S.)