IMPROVEMENTS IN THE TREATMENT OF INDIARUBBER, AND OF PRODUCTS MADE THEREFROM."
Year: 1881

page_text: COMPLETE SPECIFICATION filed by Herbert John Haddan at the Office of
the Commissioners of Patents on the 30th September 1881. A communi-
cation from abroad by Professor Doctor Ulrich Kreusler, of Bonn, Germany,
and Doctor Emil Budde, of Rome, Italy.
HERBERT JOHN HADDAN, of Kensington, Middlesex.
"IMPROVEMENTS IN THE
TREATMENT OF INDIARUBBER, AND OF PRODUCTS MADE THEREFROM." A com-
munication from abroad by Professor Doctor Ulrich Kreusler, of Bonn, Germany,
and Doctor Emil Budde, of Rome, Italy.
The principle of the process consists in saturating the indiarubber with paraffin.
This is effected by the direct contact of indiarubbor with molten paraffin; according
to the different kinds of indiarubber brought into commerce the details of the
process are subject to modifications, as will be seen from the following description:-
A.) Common or Uuvulcanized Indiarubber.-The indiarubber when used in its
crude state is to be purified and comminuted in the manner well known in every
rubber factory, after that the required quantity of paraffin is added, the mixture
exposed to a temperature of 100° C., and kept at this temperature whilst frequently
kneading and turning. (Considerable deviations from the temperature of 100° C.
are allowed, but this temperaturo is most advantageous for the process and casy to
maintain.) Within a few hours the indiarubber and paraffin combine to form a
homogeneous substance, sticky in the heat and capable of being drawn into threads.
At this stage of the process the paraffinizing is finished, and the further treatment
of the substance like that of common indiarubber, that is to say, it is placed when
still warm between woven sheets sprinkled with talc, and is rolled into sheets or
formed under strong pressure into solid blocks which can be cut into plates, &c. of
suitable thickness. The cooled product is a homogeneous mass more or less like
indiarubber, but superior to the latter through its great durability, especially
against chemicals, and therefore especially used for stopping or closing apertures.
Thin sheets of it stretched with slight tension over the mouth of a vessel will
adhere to it and shut the vessel hermetically without the use of strings.
The quantity of paraffin to be used depends upon the alteration which is to be given
to the indiarubber. If the paraffin forins from 10 to 25 per cent. of the whole mass
the product is still much like pure indiarubber and very elastic; with 30 to 40 per

page_text: cent of paraffin the elasticity is much diminished but the toughness still very great.
With this proportion the material is most suitable for manufacturing thin
diaphragms. If the proportion of paraffin rises to 50 per cent. or more the product
loses more and more the character of indiarubber, and is in its properties somewhat
like yellow wax.
If instead of the crude material the purified indiarubber from the factory is to be
had it can be used directly for paraffinizing by bringing it together in a comminuted
form with the paraffin and treating it as described.
Thin pieces of crude indiarubber of the best quality (para-caoutchouc) can be
paraffinized without previous comminution.
They are simply brought together with a suitable quantity of paraffin subjected
to a temperature of 100° C. till they have sucked up the paraffin, and are then
rolled out.
B. Vulcanized Grey or Red Indiarubber.-The ready made articles, such as tubes,
stoppers, plates, etc., are dipped into a bath of molten paraffin (temperature of
100° C. as before, advantageous but not strictly necessary). If the articles are
small they are left in the bath from a few seconds to a minute, if they are larger,
a few minutes, after which they are taken out and brought with the paraffin
coating into a chamber heated to about 100° C. where they are hung up on wires
or spread out on nets or blotting paper. Only a small portion of the paraffin
sticking to the articles will drop-down, the larger portion of it will be sucked up by
the indiarubber. When the articles seem to be dry the process is finished; they are
very littlo altered in their outward appearance, but inore durable and especially
better able to resist light and chemicals.
-
By
the-process-just-described-vulcanized articles suck up from 2 to 8 per cent.
of paraffin according to the_length_of_time_during_which they-are-left-in-the-bath.
If they are left in the paraffin longer they can be saturated much more, but the
latter is usually less expedient.
If it is required to secure a certain stock of articles against cracking or
deterioration in the store rooms, it will suffice to dip the vulcanized articles once
into molten paraffin and to store them up with the paraffin coating. Afterwards
the paraffin can be rubbed off if desired, or the process of paraffinizing completed
as described above.
C.) Desulphurized Indiarubber or Vulcanized Caoutchouc from which the super-
fluous Sulphur is Extracted by Boiling with Caustic Lye.-The paraffinizing process
is principally used for thin plates of this material as they are found in the market.
They are simply dipped into paraffin of about 100° C. and left in it from a few
seconds to several hours, according to the quantity of paraffin to bo incorporated
with them. They suck up in the shortest time about 10, in the longest time about
90 per cent. (calculated on the total quantity of the product) of paraffin and expand
accordingly. Afterwards they are put into a chamber of 100° C., as described
under B, when they are dry the operation is finished. To prevent the plates from
sticking together they may be rubbed with some talc.
Under "
paraffin" I understand the ordinary pure paraffin as it is found in
commerce. It is of variable composition, but these variations are of little influence
on this process as long as there is no unusually strong contamination.
quantity of sulphur dissolved in the melting paraffin is rather favourable to the
process, but it has no material influenco.
A small
Some substances can replace the paraffin partly or wholly as regards its action
on indiarubber; such substances are ozokerit, whose composition resembles much
that of paraffin, ceresin, neftgil, also naphtalene, anthracen, and similar solid hydro-
carbons;
besides these, wax (bec's wax and vegetable wax of any kind), stearin,
and the solid acids of the stearic acid group.
With the application of these substances the mode of procedure remains the
same as described above.
Not only articles consisting entirely of vulcanized, desulphurized, or pure india-
rubber, but also articles made from other materials and impregnated or coated with

page_text: indiarubber, or provided with indiarubber cores, may be treated by the above
described method, for instance, woven fabrics with or without indiarubber cores,
ready made garments, covers, &c., paper, various kinds of cardboard, parchment
paper, parchment, leather, further wire, and other metal work, instruments, &c.
coated or impregnated with indiarubber inay be treated with paraffin or with one
or more of the above mentioned substitutes by the process designated as para-
ffinizing indiarubber."
"
1. The process of treating indiarubber of any description or ready made articles
of such material with paraffin or substances containing paraffin, substantially as
described, and called "paraffinizing indiarubber."
2. The separate or joint application of ozokerit, ceresin, neftgil, naphtalene,
anthracen, and similar solid hydro-carbons, furthermore of wax of any kind,
stearin, and solid acids of the stearic acid group in varying proportions as partial
or complete substitutes of the paraffin in the process designated as "paraffinizing
indiarubber."
3. The treatment of articles coated or impregnated with or containing layers of
any kind of indiarubber, such as woven articles coated or impregnated with india-
rubber, with or without indiarubber cores, ready made garments, covers, &c.,
paper, various kinds of cardboard, parchment paper, parchment, leather, further
wire, and other metal work, instruments with paraffin or one of the substitutes
indicated under claim (2), or a mixture of the said substances in various
proportions, substantially as described and designated as paraffinizing india-
rubber.
In witness whereof, I, the said Herbert John Haddan, have hereunto set
my hand and seal. this Twenty-ninth day of September, A.D. 1881.