IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL LEATHER
Year: 1870

page_text: LETTERS PATENT to Peter Christian Thamsen, of Copenhagen, in the
Kingdom of Denmark, at present residing at No. 40, Great Tower
Street, in the City of London, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF ARTIFICIAL LEATHER.”—A communication from
abroad by Soren Sörensen, of Ebeltoft, in the Kingdom of Denmark.
PROVISIONAL SPECIFICATION left by the said Peter Christian Thamsen
at the Office of the Commissioners of Patents, with his Petition,
on the 11th March 1870.
I, PETER CHRISTIAN THAMSEN, of Copenhagen, in the Kingdom of
Denmark, at present residing at No. 40, Great Tower Street, in the
City of London, do hereby declare the nature of the said Invention for
“IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL LEATHER," to be as
follows:-
This Invention has for its object improvements in the manufacture of
artificial leather. For this purpose I take leather waste, leather cuttings,
leather shavings, either new or old, and reduce it to a kind of pulp by

page_text: hand labour, or by a machine or mill (either by grinding, pounding,
cutting, rasping, carding, or grating). This matter or pulp is then
kneaded with india-rubber, which is rendered fluid or dissolved in oil
of turpentine treated with ammonia, after which the mass is pressed
into forms or moulds by machine or hand labour to the shapes required, 5
or by means of rollers it is made into sheets. It is afterwards dried,
and is then ready for use.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Peter Christian Thamsen in the Great Seal Patent
Office on the 9th September 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, PETER
CHRISTIAN THAMSEN, of Copenhagen, in the Kingdom of Denmark, at
present residing at No. 40, Great Tower Street, in the City of London,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of March, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-third
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Peter Christian Thamsen, Her special licence
that I, the said Peter Christian Thamsen, my executors, administrators, 1
and assigns, or such others as I, the said Peter Ohristian Thamsen, 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
THE MANUFACTURE OF ARTIFICIAL LEATHER," a communication to me from
abroad by Soren Sörensen, of Ebeltoft, in the Kingdom of Denmark,
upon the condition (amongst others) that I, the said Peter Christian
Thamsen, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, 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.

page_text: NOW KNOW YE, that I, the said Peter Obristian Thamsen, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say :-
This Invention has for its object improvements in the manufacture of
artificial leather. For this purpose I take leather waste, leather cuttings,
leather shavings, or other small bits of leather, either new or old, and.
reduce it to a kind of fibrous pulp by hand labor or by a machine
or mill (either by grinding, pounding, cutting, rasping, carding, or
grating); if old waste is used it should first be cleaned thoroughly.
This matter or pulp is then kneaded with india-rubber, which is
rondered fluid or dissolved in oils or spirits and treated with ammonia.
I prefer to dissolve the india-rubber in oil of turpentine. To effect this
I cut the india-rubber into pieces and mix it with the oil, after which I
let it remain quiet in a closed vessel until it is dissolved. When the
india-rubber is dissolved I add ammonia of a strength of 30 per cent. in the
proportion of about equal parts by weight of ammonia to the india-rubber
contained in the solution. When the mass has become of a greyish-
white color it is ready to be mixed with the pulp. Previous to mixing
the pulp with the india-rubber solution I prefer to place the pulp in the
upper part of a vessel, which is divided in two parts by a net or sieve,
or similar contrivance. In the lower part of the vessel is placed
ammonia, and the vapours rising from the ammonia are caused to
permeate through the pulp. This operation may be hastened by heating,
but the heat must not exceed 25 degrees Reamur. This operation of
acting on the pulp with ammonia vapour is not indispensable, but is
beneficial. The pulp is afterwards kneaded with the india-rubber
solution, which has been treated with ammonia as before described,
which kneading should be carefully effected and continued until the
matter is an even mass. The proportion of pulp to the solution
may be varied according to the quality of the latter. The following
proportions give good results :-

page_text: is employed I use by preference about 4 parts oil to one part india-
rubber, or if African rubber is used about 2%, parts oil to one of rubber.
The ammonia may be added weaker, or in a smaller quantity than
stated, according to the amount of flexibility it is desired to give to
the artificial leather. The method of operation above described gives a
good leather for soles.
When the mixture of pulp and solution has been kneaded as above
described to an even mass it is pressed in forms, or by rollers or other-
wise, into the required shape. To prevent the mass sticking to the
form or roller some soft cloth or other medium must be placed between
the mass and the form or roller. If forms are used they should have a
loose bottom. The first pressure is given immediately when forming
the mass or leather, and it is sufficient if this pressure only lasts a few
minutes. The leather is then allowed to dry for about twenty-four hours,
after which it is again pressed with the cloth still on it; after this
pressure the cloth is taken off, the leather is then allowed to dry com-
pletely, after which it is pressed again between even surfaces, and is
then ready for use.
In some cases I dispense with the use of the india-rubber solution,
and employ ammonia only to act upon the leather pulp. The ammonia
is allowed to saturate the pulp and is kneaded therewith; the pulp is
then pressed in forms and allowed to dry. Leather thus made is as
hard as horn, and though useful for some purposes it cannot be used
generally in this state as a substitute for natural leather.
The quality of this artificial leather can be improved by vulcanizing.
For this purpose I take one part of chloride of sulphur (C 7. 8. 2.)
with 40 parts sulphide of carbon (C. S¹.). In this liquid the leather
remains for 5 or 6 minutes, when the intended effect has been produced.
The leather must be completely dry for this operation. The mixed
liquid may also be added to the solution of india-rubber and ammonia,
in which case I take of the liquid half the weight of the india-rubber
contained in the solution.
Having thus described the nature of my Invention and the manner
of performing the same, I would have it understood that what I claim
is,-
First. The manufacturing artificial leather from leather waste reduced

page_text: Second. The manufacturing artificial leather from leather waste
reduced to pulp and combined with ammonia and a solution of india-
rubber or similar gum as herein described.
In witness whereof, I, the said Peter Christian Thamsen have here-
unto set my hand and seal, this Thirtieth day of August, in
the year of our Lord One thousand eight hundred and seventy.