Improved Manufacture of Substitute for Leather.
Year: 1892

page_text: Date of Application, 23rd Apr., 1892-Accepted, 28th May, 1892
COLELE DIEVITICALIVE.
Improved Manufacture of Substitute for Leather.
A communication from AUGUST EMIL EBERT, of Dresden-Altstadt, Saxony, in
the German Empire, Merchant.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Member of the Institution of Mechanical Engineers, 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 consists in a process by which felt or other fibrous materials
suitably treated or impregnated may be worked into a material capable in many
cases of replacing leather. It is especially intended to manufacture soles for shoes
in this manner which will be found water-tight and damp-proof and will equal
leather soles in durability.
The process mainly consists in immersing the felt or other material in a bath
made of asphalt, fat, varnish, and oxide of iron and rendered liquid by the action
of heat. The material so immersed is then pressed and caused to pass through
calenders.
In the following detailed description of the various stages of the process, felt
is supposed to be the material chosen for the operation though all that is to be said
about it will equally apply to worsted, linen, or other fabrics, which may be sub-
stituted for it.
The best kind of felt is hair-felt containing a small proportion of wool, but it
must be well fulled and should not contain any substances soluble in water. The
projecting hairs should be removed by burning or singeing preferably by means of
a heated iron plate, so as to obtain a neat, smooth material.
For the impregnating process a pan or basin of sheet-iron may be used, which
should be somewhat larger than the pieces of felt to be treated. Into this vessel
the impregnating mass is introduced, the composition of which is particularly
specified further on. This mass is heated until it becomes quite liquid, in which
condition it may be maintained by keeping up a low fire. The mass, should,
however on no account be allowed to boil, as this would injuriously affect the felt.
The pieces of felt, before being introduced into the hath are thoroughly heated so
that every trace of moisture is removed therefrom, and it becomes capable of more
readily absorbing the impregnating liquid. For this purpose a frame is preferably
used across which wires are stretched and which is provided with handles by means
of which it is placed in and removed from the bath. The pieces of felt are by
such means easily handled and the drawback is avoided which would result from
the lowest piece of felt coming into immediate contact with the hot bottom surface
of the pan. According to the thickness of the pieces of felt, it takes them from
10 to 20 minutes to become thoroughly impregnated with the liquid in the bath.
The following is a detailed recipe of the bath,-
1 part of ozokerite or cerasine (mineral wax) is melted and to this are added
2 parts of melted beef or mutton dripping. This mixture is diluted by the addition
of from 6 to 8 parts of varnish, so that it acquires the consistency of a salve or
pomade, whereupon 2 or 3 parts of oxide of iron are added. Besides the applicant
has found it suitable in some cases to add to the mixture about % of oxide of
manganese.
This mixture is now mixed with 5 parts of asphalt, which completes the pre-
paration of the impregnating substance such as has been found by practical
experiment to answer best the purpose of the invention.
If required to increase the fluidity of the bath, resin oil may be added, which
will also prevent the liquid from hardening too quickly when no longer acted upon

page_text: by heat. In some cases an addition of turpentine-oil has also been found advan-
tageous.
After being impregnated the pieces of felt are removed from the bath one by
one, and spread over a plate, where by means of a pressure-roller, the liquid in
excess in wrung out of them; or the pieces of felt may be passed between wringing
rollers.
The next stage is the pressing of the felt, which is effected by placing each sheet
of felt between two sheets of metal covered with German or Frankfurt black and
moistened with water to prevent adhesion. A whole batch of sheets so spread are
then submitted to the action of a powerful press for a period of from 6 to 12 hours,
more pressure being preferably given from time to time. After pressing the sheets
of felt are calendered between rollers, the pressure of which is also increased
several times during the operation.
Upon issuing from the calendering rolls the felt or other material may be dressed
or varnished by being treated with very dilute asphalt varnish with the addition of
cerasine and turpentine-oil. When this is dry, brilliancy may be imparted to the
surface of the material by means of brushes or the like.
The felt may now be employed as suggested in the introduction to this Speci-
fication for cutting or stamping out soles, and other similar purposes.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is,-
1. A method of manufacture of a substitute for leather from felt or other
similar fibrous materials treated by an impregnating process which consists in
immersing the pieces of material to be treated in, and soaking them with a mixture
of asphalt fat varnish and oxide of iron rendered liquid by heating and then pressing
and calendering them.
2. The substitute for leather substantially as described.
ALFRED J. BOULT,
Chartered Patent Agent.