An Improved Process for Drying Cellulose Products.
Year: 1899

page_text: Date of Application, 29th Mar., 1899
Complete Specification Left, 23rd Dec., 1899-Accepted, 17th Feb., 1900
PROVISIONAL SPECIFICATION,
An Improved Process for Drying 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:-
The process forming the subject of our present invention is designed to impart
a greater solidity or firmness and a glossy appearance to the cellulose which is
separated from one of its known solvents (ammoniacal solution of cupric oxide,
zinc chloride, and the like), or to hydrocellulose or better, hydrate of cellulose,
In this
or amyloid, after the preparation thereof into threads, films and so on.
application amyloid means a modification of cellulose obtainable by the action of
sulphuric acid, phosphoric acid, chloride of zinc or the like on cellulose and
having a certain exterior resemblance to starch; according to "Cross and Bevan
this cellulose-amyloid is represented by the formula n(C₁ HO₁) the semi-
hydrate of n(C H₁0 O₂).
23
We have found that, when the threads, films or like products manufactured
from cellulose which is separated from its solution, or from hydrocellulose, or
better, hydrate of cellulose, are dried according to the usual method of drying
the cellulose is always converted into a porcelain-like, brittle mass, without gloss
and of little firmness or solidity.
For this reason its employment for many purposes, for example, for the
manufacture of artificial silk, was precluded.
This objection is obviated by the present invention.
After it was established, by investigations made for this purpose, which led
to the present invention, that this brittleness and lack of gloss of these cellulose
products is due to the method of drying, by further investigation, a process was
discovered whereby these cellulose products can be dried so as, at the same
time, to obtain greater firmness or solidity and a splendid silky gloss. Our
improved process consists in that the cellulose product is not brought immediately
to a temperature of 80 to 100 degrees C. in order to dry it, but is subjected to a
temperature of not above 40 degrees C., wherein the cellulose threads or the
like are retained in position in such a manner that a contraction of the cellulose
particles cannot take place. This process can be assisted by employing a vacuum
or by increasing the rate at which the air is changed. By these means, the
cellulose products give up their water of hydration and become firm and glossy.
The usual further treatment (for example, moistening, or the action of baths
followed by drying at high temperatures) can now be undertaken without in-
juring the firmness or solidity and gloss of the cellulose. For example, the
process in the manufacture of artificial silk would take place as follows:-
After the cellulose precipitated from the solvent liquid is formed into threads
and wound onto rollers, the threads at this natural tension are heated, if desired,
in a vacuum or in a strong current of air, to a temperature which does not
od 10 donross C

page_text: In this manner, transparent, highly glossy and firm cellulose threads are
formed.
The process can similarly be arranged for other operations.
Dated the 29th day of March 1899.
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:
-
The process forming the subject of our present invention relates to imparting
a greater solidity or firmness and glossy appearance to the cellulose (or cellulose
derivatives, such as hydrocellulose, the various hydrates of cellulose, or amyloid)
which have been separated in a gelatinous state from one of the known solvents
(ammoniacal solution of cupric oxide, zine chloride, and the like) and make up
into threads, films and so on. In this application, amyloid means the known
modification of cellulose obtainable by the action of sulphuric acid, phosphoric
acid, chloride of zinc or the like on cellulose.
We have found that, when the threads, films or like products manufactured
from cellulose or its above mentioned derivatives which are separated from their
solution, are dried according to the usual method of drying, these gelatinous pro-
ducts aro always converted into a porcelain-like, brittle mass, without gloss and
of little firmness and solidity.
For this reason, its employment for many purposes, for example, for the
manufacture of artificial silk, has heretofore been precluded.
This objection is obviated by the present invention.
After establishing by investigations made for this purpose, that the brittleness
and the lack of gloss of these cellulose products are due to the method of drying,
we discovered a process whereby these cellulose products can be dried so as to
obtain at the same time, greater firmness or solidity and a splendid silky gloss.
Our improved process consists in that the cellulose product is not brought immedi
ately to a temperature of 80 to 100 degrees C. in order to dry it, but is subjected
to a temperature of not above 40 degrees C., the cellulose threads or the like
being retained at the same time in such a position that a contraction of the
cellulose particles cannot take place. This process can be assisted by employing
a vacuum or by increasing the rate at which the air is changed. By these
means, the cellulose products give up their water of hydration and become firm
and glossy.
After this first drying, the usual further treatments (for example,
moistening, or treating in dyeing or other baths followed by drying at high
temperatures) can now be undertaken without injuring the firmness or solidity
and gloss of the cellulose. For example, the process in the manufacture of
artificial silk would take place as follows:-
After the cellulose precipitated from the solvent liquid, is formed into threads
it is wound on rollers or spools of a diameter the larger the better, and washed
out; the threads under this condition are heated, if desired, in a vacuum or in
a strong current of air, to a temperature not exceeding 40 degrees C.

page_text: In this manner, transparent, highly glossy and firm cellulose threads are
formed.
The process can similarly be arranged for other operations.
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. A process or method of drying cellulose-products (such as threads, films and
the like, obtained by separation of dissolved cellulose or cellulose derivatives
from their solvents), wherein the said products are heated to a temperature not
exceeding about 40 degrees C., the process being assisted, if desired, by the
action of a vacuum or of a current of air, substantially as, and for the purpose,
set forth.
2. A process or method of drying cellulose-products, consisting in winding the
said products on rollers or spools and then heating them to a temperature not
exceeding about 40 degrees C. thereby retaining the products in such a position
that a contraction of the cellulose particles is prevented, which method or process
may be assisted, if desired, by the action of a vacuum or of a current of air,
substantially as, and for the purpose, set forth.
1000
1. YOUNG & Co.,
11 & 12, Southampton Buildings, London, W.C.,
Agents for the Applicants.