HAVING REFERENCE TO THE TREATMENT OF GROUND CAOUTCHOUC, AND FOR THE PURPOSE OF RENDERING IT ELASTIC OR IMPROVING ITS ELASTICITY, AS WELL AS IMPARTING TO SUCH CAOUTCHOUC OTHER USEFUL PROPERTIES
Year: 1863

page_text: LETTERS PATENT to Liveras Hull, of the State of Massachusetts, of the
United States of America, for the Invention of "HAVING REFERENCE TO
THE TREATMENT OF GROUND CAOUTCHOUC, AND FOR THE PURPOSE OF RENDERING
IT ELASTIC OR IMPROVING ITS ELASTICITY, AS WELL AS IMPARTING TO SUCH
CAOUTCHOUC OTHER USEFUL PROPERTIES."
Sealed the 6th April 1863; and dated the 8th January 1863.
COMPLETE SPECIFICATION filed by the said Liveras Hull at the Office.
of the Commissioners of Patents, with his Petition and Declaration,
on the 8th January 1863, pursuant to the 9th Section of the Patent
Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, BE IT KNOWN
that I, LIVERAS HULL, of the State of Massachusetts, of the United States of
America, have made a new and useful Invention, "HAVING REFERENCE TO THE
TREATMENT OF GROUND CAOUTCHOUC, AND FOR THE PURPOSE OF RENDERING IT ELASTIC
OR IMPROVING ITS ELASTICITY, AS WELL AS IMPARTING TO SUCH CAOUTCHOUC OTHER
USEFUL PROPERTIES," and I do hereby declare that the nature of my said
Invention, and the manner in which the same is to be performed, are described
as follows:-
Caoutchouc when ground by means of rollers loses much of its original
elasticity, which may be restored in a measure by the ordinary process of "vul-
canizing" or mixing sulphur with the caoutchouc, and subjecting the mixture
to a high degree of heat.
My Invention differs from the said vulcanizing process, as I employ no
sulphur in mixture with with the caoutchouc, nor do I require any high or

page_text: even low degree of heat, but I make use of certain chemical liquids, simply
dipping or immersing the caoutchouc for a very short period in the compound
of them, or spreading it on them, and afterwards suffering the surface or
surfaces wet by the compound to dry.
In carrying out my Invention, I employ in connection with chloride of
sulphur the light fluid termed in commerce "carbon spirits," whose specific
gravity generally varies from 650 to 750. It is now made from the "rock
oil," which is produced from the oil wells of Pennsylvania and Canada, and is
a peculiar liquid, differing in its properties from either benzole or benzine or
coal naphtha. It has been known only during the past two or three years. It
differs from the liquids above named both in its physical and chemical charac-
teristics,; first in its specific gravity; next, in its boiling point; next, in its
evaporating without leaving any residuum; next, in not being affected by the
same chemical agents; next, in odor; next, in its special adaptation to forming
a solvent for chloride of sulphur when to be used in the treatment of
caoutchouc. When coal naphtha is mixed with chloride of sulphur the com-
pound becomes turbid, and soon deposits a bulky mass, dependent on the action
of the chloride of sulphur on one of the constituents of the naphtha; when the
compound has been applied to caoutchouc this effect continues, and even after
the chloride of sulphur has evaporated or been decomposed an adhesive matter
remains in the caoutchouc. In respect to benzole or benzine when mixed
with the chloride of sulphur and the mixture is applied to caoutchouc, the
tendency of the benzole or benzine to rapidly form a solution with the
caoutchouc causes the latter to become pulped or distended, so that the
chloride of sulphur has to act on a larger mass, and to effect in an imperfect
manner the changes which should follow its action. The employment of
benzole in other ways has so increased its demand and raised its price as to
render it too expensive a liquid to be employed practically and to economical
advantage in the treatment of caoutchouc, but the carbon spirits, besides having
all the advantages and useful properties of the benzole in its mixture with the
chloride of sulphur, and the application thereof to caoutchouc, is productive of
new, useful, and highly important results, that is to say, it does not readily
pulp the caoutchouc as is the case with the benzine or benzole; furthermore,.
it perfectly evaporates from the caoutchouc without leaving behind any body,
adhesive or otherwise, calculated to injure it. Its remarkable or important
character in connection with chloride of sulphur is, that it provides for the
decomposition of any excess of the chloride and removes it from the caoutchouc
at the same time, and thus prevents the injury arising from its after action,
which has hitherto attended the use of the chloride of sulphur when employed

page_text: .
in connection with caoutchouc. At the instant of application the carbon spirits
exerts a restraining action upon the chloride of sulphur, the latter having a
disposition to destroy the texture of the caoutchouc. Alcohol has been used
to restrain the action of the chloride of sulphur, but with imperfect results, and
this after the caoutchouc has passed from a solution of the chloride with
naphtha or other solvent. When naphtha and chloride of sulphur are mixed
together the mixture must be used immediately, otherwise it becomes decom-
posed and changed, but a mixture of carbon spirits and chloride of sulphur
may be suffered to stand for months without being used and still will retain
all its useful properties unimpaired. Furthermore, when naphtha or benzole
or benzine is used in connection with the chloride of sulphur and in the treat-
ment of caoutchouc, a very disagreeable odor remains in the caoutchouc, which
is not the case when carbon spirits is employed.
In the practical application of my Invention to caoutchouc I take one
measure of the chloride of sulphur to forty of the carbon spirits, and mix them
together. I do not, however, confine my Invention to these precise propor-
tions, as they may be somewhat varied and yet be productive of like results.
Into this mixture or solution of carbon spirits and chloride of sulphur I
immerse the ground caoutchouc for about one minute, after which it should be
removed and suffered to dry. The action of the mixture not only prevents the
caoutchouc from becoming tacky, but neutralizes the tackey properties when
present. It also restores the lost elasticity, and imparts to the caoutchouc all
the useful characteristics which it receives from the ordinary processes of
vulcanizing, without any of their disadvantages.
I do not claim the application of coal naphtha or sulphide of carbon and
chloride of sulphur to caoutchouc, nor do I claim the application of benzine or
benzole and chloride of sulphur to caoutchouc for the purposes for which such
have been used.
I claim the application of carbon spirits as described and chloride of sulphur
to ground caoutchouc, substantially as and for the improvement of it as
specified.
In witness whereof, I have hereunto set my hand and seal, this 18th