IMPROVEMENTS IN TREATING INDIA- RUBBER, AND IN THE MANUFACTURE THEREFROM OF FABRICS AND OF INSULATED TELEGRAPHIC CONDUCTORS
Year: 1868

page_text: LETTERS PATENT to
of Surroy, for the
William Hooper, of Mitcham, in the County
Invention of "IMPROVEMENTS IN TREATING INDIA-
RUBBER, AND IN THE MANUFACTURE THEREFROM OF FABRICS AND OF INSULATED
TELEGRAPHIC CONDUCTORS"
Sealed the 18th September 186, and dated the 19th March 1868.
PROVISIONAL SPECIFICATION left by the said William Hooper at
the Office of the Commissioners of Patents, with his Petition, on
the 19th March 1868.
I, WILLIAM HOOPER, of Mitcham, in the County of Surrey, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN TREATING
INDIA-RUBBER, AND IN THE MANUFACTURE THEREFROM OF FABRICS AND OF
INSULATED TELEGRAPHIC CONDUCTORS," to be as follows:-
This Invention has for its object improvements in treating india-
rubber, and in the manufacture therefrom of fabrics and of insulated
telegraphic conductors.
In the manufacture of india-rubber when the crude india-rubber has
been washed and cleaned before masticating, com pressing, grinding, or

page_text: dissolving it, as the case may be, I place it in a closed heated chamber
and raise it to a temperature of about 250 degrees Fahrenheit, and
maintain this heat for about two hours. The india-rubber after this
treatment is much easier to masticate or grind than india-rubber which
has not been so operated upon. It also, if compressed without mas-
tication, forms a solid block very similar to a block made from masticated
rubber, and also it is more readily dissolved in solvents than is the
crude rubber.
In preparing an india-rubber fabric it has before been proposed to
cement a batt or fleece of cotton or other fibre with a solution of india-
rubber, and to pass it between rollers. I according to my Invention
obtain a new and superior fabric by mixing sulphur or matter con-
taining sulphur with the india-rubber solution, and by exposing the
fabric to a vulcanizing heat after it has been made.
In the manufacture of insulated telegraphic conductors where a strand
of metal wire is insulated partially or wholly by means of a vulcanized
coating, I coat the central wire of the strand with india-rubber or a
compound of india-rubber, and into this coating the outer wires of the
strand bed themselves, and a solid strand is thus obtained.
I prefer
to use a compound of india-rubber such as can be applied to the wire
through a die.
The materials which have heretofore been used to fill up the interstices
of conducting strands will not bear the heat necessary for vulcanization.
Now according to my Invention heat necessary for vulcanization may be
used without injury.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Hooper in the Great Seal Patent Office
on the 19th September 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HOOPER, of Mitcham, in the County of Surrey, send greeting.
year of
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of March, in the
our Lord One thousand eight hundred and sixty-eight in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give

page_text: and grant unto me, the said William Hooper, Her special licence, that
I, the said William Hooper, my executors, administrators, and assigns,
or such others as I, the said William Hooper, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN TREATING
INDIA-RUBBER, AND IN THE MANUFACTURE
THEREFROM OF FABRICS AND OF
INSULATED TELEGRAPHIC CONDUCTORS," upon the condition (amongst others)
that I, the said William Hooper, my executors or administrators, by
an instrument in writing under my, or their, or one of their hand and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said William Hooper, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say:-
In the manufacture of india-rubber when the crude india-rubber has
been washed and cleaned before masticating, compressing, grinding, or
dissolving it, as the case may be, I place it in a closed heated chamber and
raise it to a temperature of about 250 degrees Fahrenheit, and maintain
this heat for about two hours. The closed heated chamber into which
the rubber is placed I prefer to heat by means of a steam jacket around
it, as steam must not be allowed to come in contact with the rubber.
I place the rubber in sheets as it comes from the rollers of the washing
machine ordinarily employed for washing and cleansing the rubber into
the heated chamber, such sheets being by preference placed one above
the other to the depth only of about two to three inches, so that the
heat of the chamber will readily penetrate through the piles of sheets.
The india-rubber after this treatment is much easier to masticate or
grind than india-rubber which has not been so operated upon. It also,
if compressed without mastication, forms a solid block very similar to
a block made from masticated rubber, and may be cut into sheets or
threads and elastic fabrics manufactured therefrom; and also it is more

page_text: readily dissolved in solvents than is the crude rubber, and such dissolved
india-rubber may be used to produce waterproof fabrics.
In the manufacture of insulated telegraphic conductors where a strand
of metal wires is insulated partially or wholly by means of a vulcanized
coating, I coat the central wire of the strand with india-rubber or a
compound of india-rubber, and into this coating the outer wires of the
strand bed themselves, and a solid strand is thus obtained. I prefer to
use a compound of india-rubber such as can be applied to the wire
through a die.
The materials which have heretofore been used to fill up the interstices
of conducting strands will not bear the heat necessary for vulcanization,
but would become charred or vapourized if subjected to such heat.
Now according to my Invention heat necessary for vulcanization may be
used without injury.
The composition I have found in practice suitable consists of a
mixture of india-rubber and oxide of zinc in the proportion of 32 lbs. of
india-rubber to 16 lbs. of oxide of zinc. I have found that about three
hours grinding by means of heated rollers is sufficient to make such
a composition work through a die or orifice. It is necessary that the
cylinder which feeds the die should have a steam chamber or jacket
around it or be otherwise heated, and be kept at a temperature of
about 250° Fahrenheit, so that the compound may be sufficiently plastic
to be moulded by the die. In place however of the compound of india-
rubber above given, other compounds of india-rubber with materials
which will bear the heat necessary for vulcanization may be employed.
In witness whereof, I, the said William Hooper, have hereunto
set my hand and seal, this Nineteenth day of September, in
the year of our Lord One thousand eight hundred and sixty-
eight.
WILLIAM HOOPER (L.S.)