An Improved Process for the Metallic Coating and Ornamenting of Paper.
Year: 1897

page_text: Date of Application, 5th Oct., 1897-Accepted, 5th Oct., 1898
COMPLETE SPECIFICATION.
An Improved Process for the Metallic Coating and Ornamenting of
Paper.
I, CARL ENDRU WEIT, of 12, Triftstrasse, Berlin, W., in the Empire of Germany,
Manufacturer, 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 relates to an improved process for coating paper with metal
by a galvanic process, hitherto it has only been possible to produce separate
sheets of metal paper, and consequently the use for which it is applicable. is
limited. By the process herein described it is possible, to produce metal paper
in any length and of various widths and its use is thus applicable to more vary-
ing purposes in industry.
In order to produce metallic paper in continuous rolls and of different metals
or alloys, an apparatus or the combination of different apparatus is used and is
shown in the annexed drawing. The single metal plates used hitherto for pro-
ducing metal paper are here replaced by an endless metal band B serving as
cathode and corresponding with the width of the metallic paper to be produced,
this metal band being guided over a convenient number of guiding rollers R.
The outward surface of this metal band can be either highly polished, or ground
dull or provided with lightly engraved or punched designs according to the
pattern if any which is to be produced on the metal paper. This metal band B
is brought into perpetually progressive movement by turning the rollers R,
which movement can be effected either quickly or slowly according to the thick-
ness of the metal deposit required by correspondingly varying the gearing wheels
of the driving mechanism.
The different rollers R are electrically connected together; the metallic guiding
cylinders or rollers R, outside the galvanic baths are connected to the negative
pole, whilst the positive pole is connected directly with the anode of the copper
or nickel bath. The speed of travel of the band is regulated so that with a
current of 2 amperes per square decimeter the cathode band is moved 15 minutes
through the copper bath. This shows that for obtaining the required thickness
of metallic precipitation the speed can be very different, for if the copper bath
and consequently the cathode band is very long, this latter must be moved quicker
than if they are only short in which case the cathode band is moved more slowly.
Suppose for instance the cathode band guided upon the rollers R is 25 m. long,
only 10 of them touching the copper bath, consequently the rapidity must be
only 066 m. in a minute. During its passage the metal band first passes an
appropriate grinding or polishing device S, which serves to remove unevenness.
and spots etc. during the passage of the band; then the band passes to a
receiver F containing, for the purpose of forming an insulating layer, a solution
of potassium tri-sulphide of hydric sulphide or sulphide of hydrogen with potas-
sium sulphide (for instance five parts by weight of potassium tri-sulphide and
100 parts water); and passing over the receiver F the moving band is wetted
071

page_text: with the said liquid by means of an appropriate mop or any other convenient
arrangement and then guided over a rubber roller G.
After the band has passed the latter it is washed with water by means of an
appropriate washing device V and passes then successively first, when for
instance nickel paper is to be produced, through a nickel bath (containing for
example a 5 per cent. solution of sulphate of nickel and ammonia) and from
there into a copper bath (containing for instance a 25 per cent. solution of copper
sulphate). The copper bath is shown in the drawing as being considerably
longer than the nickel bath, because only a thin layer of nickel is needed on the
metal band whilst the successive copper layer to be deposited on the already
produced nickel layer has to be much stronger since it serves for strengthening
the nickel layer. The baths can also be replaced by those made with other metal
solutions. In the baths the anode plates A are shaped to follow the course of the
band. After the metal band has passed the last of the baths, it immediately
undergoes a thorough washing and passes then to the place where a continuous
paper is guided down from a paper roll P on to the metal band. The paper is
simultaneously exposed to treatment by a roller L with a sticking cement made
of glue and starch dissolved in water to which there is added one per cent. of a
solution of ammonium sulph-hydrate, mercaptan or sulphide of allyl and then it
is pressed on the metal band by means of two rubber rollers G¹; thereupon the
metal band united with the paper passes to a drying device T consisting of a box
and traversed by heat radiators, where the sticking cement is dried. Imme-
diately after passing this drying device the finished product consisting of the
paper with the metal coating now adhering thereto is disengaged from the metal
band and is wound upon a roller W.
Fig. 2 shows a partial variation of the before described apparatus, in which
the anodes are arranged as flat plates under the cathode plate constituting the
band B, so that only a small free space remains between the cathode plates and
the anode plates, into which the liquid from the baths is constantly pumped by
means of appropriate pumping devices, so that the bath is in constant circulation.
Having now particularly described and ascertained the nature of this in-
vention and in what manner the same is to be performed I declare that what I
claim is
An improved process for the metallic coating of paper in rolls, in which an
endless metal band guided over guiding rollers and conveniently insulated on
its surface is guided through a number of galvanic baths in a quicker or slower
manner according to the thickness of the deposit to be formed and to which a
paper band running from a roller is then applied, such paper band having been
previously coated with a cementing matter, the two bands being then guided
through a drying apparatus and afterwards detached so that the paper band carries
away the metallic coating from the metal band.
Dated this 5th day of October 1897.
HERBERT HADDAN & Co.,
Agents to Applicant,
18, Buckingham Street, Strand, London.