Improvements in and relating to the Drying of Cellulose-products.
Year: 1899

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to the Drying of Cellulose-products.
We, Dr. MAX FREMERY, Chemist, and JOHANN URBAN, Engineer, both of
Dorfstrasse, Oberbruch, Reg. Bez. Aachen, in the German Empire, do hereby
declare the nature of this invention to be as follows:-
-
A process is already known wherein, in order to obtain more solid or firmer
and more glossy cellulose-products made from cellulose which is separated or
precipitated from solvents thereof, or from hydro-cellulose or amyloid, these
cellulose-products, after their manufacture, are dried at a temperature not
exceeding 40 degrees Centigrade. This process can be promoted by employing
a vacuum or a current of air. In this connection, it is to be taken into con-
sideration, that these cellulose-products (such as threads, films or the like) are
wound on rollers, whilst they are subjected to this drying process, the cylin-
drical rollers everywhere acting uniformly in opposition to the natural con-
traction which takes place, whilst the gradual removal of water produces an
uniform tension of the thread or film throughout, which is necessary for attain-
ing the high gloss and the close similarity to silk.
In practical experiments with this process, it has been observed that the
drying takes place in two stages or phases. A first part of the water contained
in the threads evaporates fairly rapidly, the greater part however, only evaporates
very slowly.
We concluded from this, that this larger part of the contained
water is in a fixed, possibly chemical, combination with the cellulose. This
slowly evaporating part of the water may therefore be called here
hydration of the cellulose."
water of
Further experiments were therefore undertaken, which had the object of
rendering the water of hydration" at least looser in its combination with the
cellulose, in order, possibly, by these means, to be able to evaporate this firmly
united quantity of water contained in the cellulose-products, in the drying pro-
cess, more rapidly than or as rapidly as the first part of the water contained
therein.
The desired result cannot be attained by a simple elevation of the tempera-
ture of the drying chamber, since a browning er discolouration of the cellulose
thread takes place, and the gloss and firmness thereof are deteriorated.
In these experiments, we arrived at the following process, forming the sub-
ject of our present invention :
The rollers, on which the still more or less gelatinous cellulose threads or
films are wound, are dipped for a short time in hot water (at a temperature of
from 70 to 100 degrees Centigrade) or brought into contact with a current of
steam, that is to say, the rollers, on which the manufactured cellulose-products
are wound, are subjected to the action of a high temperature (from 70 to
100 degrees Centigrade) in the presence of water (liquid or gaseous). By this
action, the result is actually attained that the whole of the water is now easily
removable by drying. After this treatment, the cellulose threads, films or the
like on the rollers are subjected to a suitable drying process, for example, they

page_text: are subjected to a moderate heat (up to about 40 degrees Centigrade) preferably
in suitable drying chambers, wherein this drying process can be promoted by
employing a vacuum or an accelerated change of the. air (attained by ventila-
tion) By employing the preliminary treatment above mentioned (action of a
high temperature in the presence of water) for this drying process, only about
a quarter of the time heretofore required for the latter, is necessary. The
threads or films here also have the valuable high degree of firmness or solidity
and the silk-like gloss.
1
101
1
1
1000
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.
Improvements in and relating to the Drying of Cellulose-products.
We, Dr. MAX FREMERY, Chemist, and JoHANN URBAN, Engineer, both of
Dorfstrasse, Oberbruch, Reg. Bez. Aachen, in the German Empire, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
In the Specification of former Letters Patent granted to us and dated 29th
March 1899, No. 6735, a process is described which consists in that, in order to
obtain more solid or firmer and more glossy cellulose-products made from cellu-
lose which is separated or precipitated from solvents thereof, or from hydro-
cellulose or amyloid, these cellulose-products, after their manufacture, are dried
at a temperature not exceeding 40 degrees Centigrade. This process can be
promoted by employing a vacuum or a current of air.. In this connection,
it is to be taken into consideration, that these cellulose-products (such as threads,
films or the like) are wound on rollers whilst they are subjected to this drying
process, the cylindrical rollers everywhere acting uniformly in opposition to the
natural contraction which takes place, whilst the gradual removal of water
produces an uniform tension of the thread or film throughout, which is neces-
sary for attaining the desired high gloss tensile strength and elasticity.
In practical experiments with this process, it has been observed that the
drying takes place in two stages or phases. A. first part of the water contained
in the threads evaporates fairly rapidly, the greater part however, only evaporates
very slowly. We concluded from this, that this larger part of the contained
water is in a fixed, possibly chemical, combination with the cellulose. This
slowly evaporating part of the water may therefore be called here
hydration of the cellulose."
« water of
Further experiments were therefore undertaken, which had the object of
rendering the water of hydration" at least looser in its combination with the
cellulose, in order, possibly, by these means, to be able to evaporate this firmly
united quantity of water contained in the cellulose-products, in the drying pro-
cess, more rapidly than or as rapidly as the first part of the water contained
therein.
The desired result cannot be attained by a simple elevation of the tempera-
ture of the drying chamber, since a browning or discolouration of the cellulose
thread takes place, and the gloss and firmness thereof are deteriorated.
In these experiments, we arrived at the following process, forming the sub-
ject of our present invention:

page_text: The rollers, on which the still more or less gelatinous cellulose threads or
films are wound, are dipped for a short time in hot water (at a temperature of
from 70 to 100 degrees Centigrade) or brought into contact with a current of
steam, that is to say, the rollers, on which the manufactured cellulose-products
are wound, are subjected to the action of a high temperature (from 70 to
100 degrees Centigrade) in the presence of water (liquid or gaseous). By this
action, the result is actually attained that the whole of the water is now easily
removable by drying. After this treatment, the cellulose threads, films or the
like on the rollers are subjected to a suitable drying process, described
in our said former Specification, No. 6735, wherein they are sub-
jected to a moderate heat (up to about 40 degrees Centigrade) preferably
in suitable drying chambers, wherein this drying process can be promoted by
emploving a vacuum or an accelerated change of the air (attained by ventila-
tion) By employing the preliminary treatment above mentioned (action of a
high temperature in the presence of water) for this drying process, only about
a quarter of the time heretofore required for the latter, is necessary.
threads or films here also have the valuable high degree of firmness or solidity
and the silk-like gloss.
The
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. An improvement in the process for attaining greater firmness or solidity
and silk-like gloss for cellulose-products made from cellulose which is separated
or precipitated from its solvents, or from hydro-cellulose or amyloid during
drying of these cellulose-products at a low temperature not exceeding about
40 degrees Centigrade as set forth in the Specification of Letters Patent No. 6735
of 1899, characterized thereby that these cellulose-products are in the first place
subjected for a short time to the action of a high temperature (from about 70
to 100 degrees Centigrade) in the presence of water (liquid or gaseous) and the
drying then carried out at a low temperature.
2. The process claimed in Claim 1, carried out whilst the cellulose-products
are wound on cylindrical rollers.
TL thi 1417
J
T
1000
D. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.