IMPROVEMENTS IN TANNING SKINS AND IN THE MANUFACTURE OF COMPOUNDS THEREFOR
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, WILLIAM CLARK of the Firm of A. M. & W Clark of 58, Chancery.
Lane, in the County of Middlesex, Fellow of the Institute of Patent Agents, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN TANNING
SKINS AND IN THE MANUFACTURE OF COMPOUNDS THEREFOR," communicated to
me from abroad by Professor Emanuel Herrmann of Vienna in the Empire of
Austria, Doctor of Law, through his Agents Wirth and Company of Frankfort on
the Main in the Empire of Germany, to be as follows:-
This Invention relates to the manufacture and employment of new combinations.
of ingredients which not only have a tanning action but by the formation of very
fine and durable coatings on the fibres of the skin impart all the qualities of leather
thereto.
These leather forming compounds are crystallisable bodies produced by treating
resin, wax, fat, oil, sugar and dextrin or glue with metallic salts suitable for or used.
to promote the tanning process, whereby substances soluble in water are produced,
which when precipitated on the fibres of the skin become insoluble and form
leather.
The new leather forming compounds are produced by boiling resin, wax, fat, oil,
sugar and dextrin or glue for several hours (preferably by steam heat in 'boilers'
provided with agitators) with from 5 to 35 times the weight of metallic salts'
(particularly the sulphates of alumina, magnesia, zinc,, copper, iron and chromium)
previously dissolved in water, and either evaporating to dryness or reducing to a
density of 50° Baumé and allowing to crystallize out preferably in lead lined
wooden vessels. The above ingredients may be boiled separately with one of the
metallic salts aforesaid but it is preferable to boil all the ingredients to be used
together, to incorporate them, and thereby form easily crystallisable bodies. Care

page_text: сорин
Tallow or its derivatives,.
Grape sugar or grape sugar syrup,
Dextrin,
Glue,
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10
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I Lo +
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These ingredients can be used separately or in groups.
Amongst the numerous combinations which may be used with success the
following may be particularly noted:-, rd, the and th the quantities of the
sulphates of magnesia, zinc, and iron, and 3rd, 4ths and 13 the quantity of chrome
aluin may be employed and the proportions of the remaining ingredients
accordingly.
The tallow can be partially replaced or supplemented by the following materials
in like proportions for the kinds of leather undermentioned, viz ;-
(a.) For wash leather by glycerine and vaseline.
(b.) For kid leather by petroleum or olive oil.
(c) For upper leather by vaseline and eloine, also margarine.
(d.) For strup leather by crude vaseline and paraffin, also by rape oil and
ozokerit.
(e.) For solo leather by ceretin and stearine, and also by linseed oil.
For light kinds of leather, (wash, kid, and upper leather) cane sugar may be used
instead of grape sugar. For sole leather grape sugar (or cane sugar and cane sugar
syrup) dextrin and glue may be used in two to four times the above proportions
and resin oil may be replaced by oil of turpentine or by liquid resin.
The operation is as follows:-The goods prepared in the usual way are placed in
an aqueous solution of the new compound. During the operation the strength of
this solution may be raised from one-half to 15 per cent. The addition of common.
salt or of potassium or sodium nitrate in the proportion of to the weight of the
compound hastens and improves the operation.
The operation is completed in 3 to 14 days for the lighter kinds of leather, and
in 12 to 40 days for strap and sold leather.
If the metallic salts be compounded separately with separate parts of resin, wax,
fat, oil, sugar, dextrin, and glue, and these be first combined together and with
chrome-alum in the bath, the combination of aluminum and glue must first he
effected, but the boiling of the whole of the ingredients together as above described,
is preferred.
In order to rapidly produce leather resembling ordinary tanned leather in touch,
color, and smell, the goods are first treated with a solution of the compound of this
Invention and then tanned in the usual bark extract liquor, or vice versa. But in
this case the sulphate of iron is to be omitted and it may also be omitted in other
cases for glove and wash leather.

page_text: COMPLETE SPECIFICATION,
"
I, WILLIAM CLARK, of the firm of A. M. and Wm. Clark, of 53, Chancery Lane,
in the County of Middlesex, Fellow of the Institute of Patent Agents, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN TANNING SKINS AND
IN THE MANUFACTURE OF COMPOUNDS THEREFOR," (a communication to me from
abroad by Professor Emanuel Herrmann of Vienna in the Empire of Austria,
Doctor of Law, through his Agents Wirth and Company of Frankfort on the Main
in the Empire of Germany,) and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:,
This Invention consists in the production and employment of a combination of
materials, which possess tanning properties and cover the fibre of the skin with
a fine and permanent formation giving all the properties of leather.
The essential feature of this invention is the production and use for tanning
purposes, of certain new and singular combinations of mineral salts which are
soluble in water with resins and other organic tanning substances, a considerable
proportion of which is not soluble in water, the resulting product being a substance,
the components of which are partly soluble in water and partly, if not soluble in
water, at least atomizable or emulsifiable in water. The essential condition of
a good tanning agent is its solubility, or at least its thorough atomizability or
emulsifiability in water, which serves us the vehicle to bring the said dissolved and
atomized or emulsified substances into intimate contact with the fibre of the hide,
the said substances becoming by such contact insoluble and precipitated on the
fibre. By this Invention an intimate union of two very valuable tanning agents
viz mineral salts and resin, fat or other organic tanning substances is effected,
the product of such union being capable of being carried by water into and
through the hides and into intimate contact with its tibres, which act as précipitants
for said combined substances. By this means both. a mineral and an organic
tanning is effected at one and the same time, whereas previous to this invention,
only a mineral or only a vegetable or organic tanning, or a mineral tanning
following or preceding a vegetable or organic tanning, has been possible.
The new tanning materials (leather formers) are produced from rosin, wax, fat,
oil, sugar, dextrine or glue, mixed with five to thirty times their weight of tanning
metallic salts, that is to say metallic salts, which further the process of tanning,
preferably with the sulphates of aluminum, magnesium, zinc, copper, iron and
chromium, with the addition of as much cold water as is necessary to dissolve the
Balts. These materials are boiled together for several hours under continual
stirring, preferably by steam heat. This boiling is either continued until the mass
is evaporated and dried or else it is boiled down to a concentrated solution of
45° to 50° Beaumé. During the process of boiling no more water has to be added,
unless the mass begins to adhere to the sides of the vessel, this however can be
avoided by careful boiling,-when it is drawn off to crystallize in suitable vessels ;
wooden vessels lined with lead are considered best for the purpose. The boiling
is best effected in open vessels, so that the concentration can be continually
observed.

page_text: I have found the following materials mixed in the proportions mentioned to
produce an excellent tanning composition
39 to 46 parts by weight sulphate of alumina.
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Epsom salts.
Zinc vitriol (sulphate of zinc).
Green vitriol (sulphate of iron).
chromate of álum.
rosin, oil and about twice as much oil of.
turpentine.
Japanese wax or bees wax.
tallow or its derivatives stearine, Oleine,
glycerine &c &c.
grapo Bugar or grape sugar syrup.
dextrino.
gluo, gluten, carragheen or lineeed slime.
Among the many combinations of the above named materials, which have been
employed with success, the materials and proportions mentioned below are those
which I especially recommend.
The metallic salts can be employed in increased proportions to the weights given,
up to 6 times as much as named while the proportions of the other materials
remain unaltered.
In particular the bitter-salt (sulphate, of zinc) and green vitriol (sulphate of iron)
can be employed in the proportion of up to be of the above mentioned weight
and the chromate of alum in the proportion of 4, 4 and 1.
The tallow named above as a part of the new tanning material, can be replaced
by the following materials in tanning the following leathers, the proportions in
weight remaining the same.
(a) For chamois-leather, by glycerine and vaseline.
(b) For glovo-leather, by petroleum or olive oil.
For upper leather, by vaseline, oleine (elaine), or margarine.
For machine belt leathers, by raw vaseline and paraffine, also by rape oil
(oil of rape seed) and ozokerite.
(6) For sole leather (butts) by claine (oleine) and ceresine.
Besides which, in place of grape-sugar, cane-sugar and also syrup can be
employed for the lightest sorts of chamois, glovo and upper leather. This how-
ever does not exclude the use of the specified materials as tanning materials for
other sorts of leather.
The necessary proportions are shown by the foregoing, and can be easily
determined by any chemist.
These materials can also be arranged in groups,-which is even advisable in
some sorts of leather.
By boiling, the whole of the materials or their substitutes, they unite with each
other in the proportions of weight stated, and form a uniform crystallizable
substance.
According to the proportion of water and according to the composition of the
natural tanning materials, the proportion of the colloids to the metallic salts and
the other crystallizers, the new tanning material is either crystalline, or a paste,
or a watery fluid. This new tanning material is employed for tanning in the
same manner as ordinary bark extracts, that is to say dissolved in water in a
stronger or weaker solution. Common salt or saltpetre can be added to the new
tanning material in the process of tanning chamois leather in the same proportions
and manner as is now done in order to accelerate the tanning process. This cannot
be done when extracts of bark are employed.
The process of tanning with this new tanning material is as follows:-
The skins to be treated are prepared in the usual manner for tanning but in
place of using bark or similar vegetable tanning substances, they are steeped in a

page_text: solution of the new tanning substance. The strength of this bath can be gradually
increased during the tanning process from 7 to 75% weight. An addition of one
third to one half of the weight of the tanning materials, of common salt or nitrate
of soda or nitrate of potash accelerates and perfects the tanning process.
The process of tanning is complete for light sorts of leather in 3 to 14 days;
with sole and belt leathers however in 12 to 40 days.
The tanning process is quite as quick as the mineral tanning process but differs
from this most essentially in the fact that it is dependent on the employment at
the same time of organic and inorganic matters combined in the form of double
salts which are tannic, that is to say are leather-formers.
The process of vegetable tanning can be combined with this process if desired.
In this case the hides are first subjected to the tanning action with this composition
and then treated with vegetable tanning liquor, or vice versa; in this case however
the sulphate of iron (green vitriol) must be omitted.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is
1st The process of producing combinations which are partly soluble and partly
atomizable or emulsifiable in water, and suitable for tanning purposes, the process
consisting in boiling together aqueous solutions of metallic salts and organic
tanning substances, such as resins or their equivalents, substantially as described.
2nd As an article of manufacture, the herein before described partly soluble and
partly atomizable or emulsifiable combinations of metallic salts with organic
tanning substances.
3rd The process of tanning hides by means of the herein before described partly
soluble and partly atomizable or emulsifiable combinations of metallic salts with
organic tanning substances, the said combinations being used alone or in co-operation
with or subsequent or precedent to other known tanning agents.
4th As an article of manufacture, leather which has been made, tanned or
prepared by means of the herein before described partly soluble and partly
atomizable or emulsifiable combinations of metallic salts with organic tanning
substances.