IMPROVEMENTS IN RE-WORKING OR RE-MANUFACTURING COMPOUNDS OF INDIA-RUBBER AND SULPHUR
Year: 1859

page_text: LETTERS PATENT to William Hooper, of Mitcham, in the County of
Surrey, India-rubber Manufacturer, for the Invention of "IMPROVEMENTS
IN RE-WORKING OR RE-MANUFACTURING COMPOUNDS OF INDIA-RUBBER AND
SULPHUR."
Sealed the 7th October 1859, and dated the 8th April 1859.
PROVISIONAL SPECIFICATION left by the said William Hooper at the
Office of the Commissioners of Patents, with his Petition, on the
8th April 1859.
I, WILLIAM HOOPER, of Mitcham, in the County of Surrey, India-rubber
Manufacturer, do hereby declare the nature of the Invention for "IM-
PROVEMENTS IN RE-WORKING OR RE-MANUFACTURING COMPOUNDS OF INDIA-RUBBER
AND SULPHUR," to be as follows:-
This Invention has for its object improvements in re-working or re-
manufacturing compounds of india-rubber and sulphur. At the present.
time articles of vulcanized and hard india-rubber which have been injured.
in the process of manufacture, or which have become worn out, have but a.
small commercial value in consequence of the great difficulty of again working
up the material. Now, according to my Invention, I grind the material to.
powder by means of crushing rollers or otherwise; or if in the form in which
the material is obtained it is too soft to be so ground, I first heat it to render,

page_text: the material sufficiently bard to grind; when it is reduced to a fine powder
I mix it with a small quantity of raw india-rubber, or with other substance
which will make the powder adhere together, and I usually add a proportion
of sulphur; I then mould or form the eompound to the shape desired, and
submit it to heat sufficient to change it to a hard or semi-hard substance; and
I find that for this purpose a less heat is required than is usually employed to
convert mixtures of raw india-rubber and sulphur into the well-known hard or
semi-hard substance formed by heating such mixtures. The heat necessary
to produce the change may be still further reduced by adding to the compound
lime, shellac, and hard bituminous substances. By mixing a larger quantity
of raw india-rubber with the ground material, and employing less heat, a
substance in some degree approaching in character to ordinary vulcanized
india-rubber may be obtained.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by tho said William Hooper in the Great Seal Patent Office on the
8th October 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HOOPER, of Mitcham, in the County of Surrey, India-rubber Manufacturer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of April, in the year of our Lord
One thousand eight hundred and fifty-nine, in the twenty-second year of
Her reign, did, for Herself, Her heirs and successors, give 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, administrators, 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 RE-WORKING OR RE-MANUFACTURING COMPOUNDS OF INDIA-
RUBBER AND SULPHUR," 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 hands and scals, should par-
ticularly 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

page_text: 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 per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
This Invention has for its object improvements in re-working or re-
manufacturing compounds of india-rubber and sulphur.
At the present
time articles of vulcanized and hard india-rubber which have been injured
in the process of manufacture, or which have become worn out, have but
a small commercial value in consequence of the great difficulty of again
working up the material. Now, according to my Invention, I grind the
material to powder by means of crushing rollers or otherwise; or if in the
form in which the material is obtained, it is too soft to be so ground, I first
heat it to render the material sufficiently hard to grind; when it is reduced
to a fine powder I mix it with a small quantity of raw india-rubber, or with
other substance which will mako the powder adhere together, and I usually
add a proportion of sulphur; I then mould or form the compound to the
shape desired, and submit it to heat sufficient to change it to a hard or semi-
hard substance; and I find that for this purpose a less heat is required than
is usually employed to convert mixtures of raw india-rubber and sulphur into
the well-known hard or semi-hard substance formed by heating such mixtures.
The heat necessary to produce the change may be still further reduced by
adding to the compound, lime, shellac, and hard bituminous substances. By
mixing a larger quantity of raw india-rubber with the ground material, and
employing less heat, a substance in some degree approaching in character to
ordinary vulcanized india-rubber may be obtained.
Having thus stated the nature of my said Invention; I will proceed more
fully to describe the manner of performing the same.
The waste or old vulcanized india-rubber, or hard compound of india-rubber
and sulphur, are first reduced into as fine a state as may be by grinding, as has
heretofore been practised, and to which I lay no claim; but I prefer to employ
that process of grinding which consists of two rollers moving at different sur-
face speeds. Having reduced such sulphur compounds to powder, I mix and
masticate the same with a quantity of raw india-rubber and sulphur, with or
without other matters (such as have before been used when making hard and
semi-hard compounds of india-rubber and sulphur by heat), and the mixture
is then subjected to heat. A convenient mixture (though the proportions may
be varied) is obtained by combining at the rate of thirty parts by weight of

page_text: the ground product obtained from waste or old converted sulphur compounds
of india-rubber, ten parts by weight of raw india-rubber, seventeen to twenty
parts by weight of sulphur, and four parts by weight of lime, or of magnesia,
or of silicate of magnesia. These are masticated or ground, and the mixture
is then moulded or formed into the articles desired. When moulded, tho
articles are heated whilst in the moulds, as is well understood, in order to
convert the combined matters into a hard compound. When the articles are
not moulded, then they are to be heated and converted in like manner to that.
in which similar articles are converted when compounded of raw india-rubber
and sulphur. In converting compounds of india-rubber such as above
described, I do not find that so much heat is required as when using raw
india-rubber and sulphur; on the contrary, I have usually found that the
process of converting such compounds by heat takes less time, but in other.
respects is conducted as heretofore. When using large proportions of raw
india-rubber and small proportions of the ground product, articles may be
made more nearly resembling vulcanized india-rubber.
Having thus described the nature of my Invention, and the manner of
performing the same, I would have it understood that what I claim is, the.
combining raw india-rubber and sulphur, or matters containing sulphur (with
or without other substances) with the ground product of waste or old con-
verted sulphur compounds of india-rubber, and subjecting the same to high
degrees of heat to convert or change the same into elastic and hard
compounds.
In witness whereof, I, the said William Hooper, have hereunto set
my hand and seal, this Seventh day of October, in the year of our
Lord One thousand eight hundred and fifty-nine.
WILLIAM HOOPER. (L.S.)