IMPROVEMENTS IN RE-WORKING WASTE VULCANISED INDIA-RUBBER
Year: 1861

page_text: LETTERS PATENT to Thomas Forster, of Sparrow Hall, Streatham, in the
County of Surrey, India-rubber Manufacturer, for the Invention of
"IMPROVEMENTS IN RE-WORKING WASTE VULCANISED INDIA-RUBBER."
PROVISIONAL SPECIFICATION left by the said Thomas Forster at the
Office of the Commissioners of Patents, with his Petition, on the 16th
October 1861.
I, THOMAS FORSTER, of Sparrow Hall, Streatham, in the County of Surrey,
India-rubber Manufacturer, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN RE-WORKING WASTE VULCANISED INDIA-RUBBER," to be as
follows:-
This Invention has for its object improvements in re-working waste
vulcanized india-rubber. For this purpose the vulcanized india-rubber is
suitably reduced by crushing rollers or otherwise, and is then mixed with
gutta percha and sulphur, for example, three parts of waste vulcanized india-
rubber may be combined with one part of gutta percha, six ounces of sulphur
being added to each pound of the mixture, but these proportions may bé
greatly varied; this compound is moulded or rolled to the form required, and
is cured by heat, as is usual in the production of bard india-rubber or

page_text: vulcanite. In this manner a material very closely resembling vulcanite is
obtained, and which may be applied to similar uses.
Pigments may be added to the mixture of vulcanized india-rubber, gutta
percha, and sulphur, if desired.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Forster in the Great Seal Patent Office on the
16th April 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
FORSTER, of Sparrow Hall, Streatham, in the County of Surrey, India-rubber
Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of October, in the year of our
Lord One thousand eight hundred and sixty-one, in the twenty-fifth year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Thomas Forster, Her special licence that I, the said
Thomas Forster, my executors, administrators, and assigns, or such others
as I, the said Thomas Forster, 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 WASTE VULCANIZED INDIA-RUBBER," upon the
condition (amongst others) that I, the said Thomas Forster, my executors
or administrators, by an instrument in writing under my, or their, or one
of their hands 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 1, the said Thomas Forster, 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 waste
vulcanized india-rubber.
For this purpose the vulcanized india-rubber is

page_text: suitably reduced
crushing rollers or otherwise, and is then mixed with
gutta percha and sulphur.
Pigments may be added to the mixture of vulcanized india-rubber, gutta
percha, and sulphur, if desired.
I find that a very useful compound is formed by combining vulcanized
rubber at the rate of 75 lbs. of vulcanized waste rubber with 25 lbs. of gutta
percha and 35 lbs. of sulphur to the above, 100 lbs. when intended to produce
a hard gum; (if for soft goods, 5 lbs. of sulphur only.) To combine the above
I first clean and thoroughly dry both the vulcanized india-rubber and gutta
percha; I then pass the waste india-rubber several times between a pair of
rollers, heated by steam to about 120° Fahrenheit, until it is finely pulverized,
and somewhat adhesive; I then divide the bulk into parcels of 15 lbs., and
add to each parcel 5 lbs. of gutta percha; and 7 lbs. or other proportion of
sulphur; when they are thoroughly combined I put the, mass into a hot
chamber or box, heated to about 120° Fahrenheit, until the remaining parcels
are combined, when I place the whole into a hot masticator, and having well
incorporated the parcels of the compound I proceed as in making blocks of
other kinds of india-rubber, viz., I press the masses in moulds, and cut the
moulded masses into sheets by the usual machines, all of which is well under-
stood; or I at once mould the compound into the forms desired, and submit
the same to heat in order to convert or cure them.
Suppose the article required to be moulded is a tea tray, I use a sheet of
the compound rather more in weight than it is to be when the article is
finished. I slightly grease and warm the parts of the mould which is to bę
used, and I make the sheet of india-rubber compound hot on a steam chest.
The india-rubber compound is to be placed between the parts of the mould
which are to be pressed tightly together in a screw or other press. When
cold the mould may be opened, and the partially formed tray taken out, pared,
and replaced in the mould, which is again greased before replacing the tray
therein. The tray is then again pressed and subjected to heat whilst in the
mould for about five and a half hours, preferring a heat of about 300° Fahren-
heit, by which the well known change will be produced in the india-rubber
compound.
It should be stated that the above proportions of waste vulcanized india-
rubber and gutta percha may be greatly varied; for instance, more or less
gutta percha may be employed in proportion to the waste vulcanized india-
rubber or raw india-rubber may be substituted for part of the waste vulcanized
india-rubber; coloring or other matters may also be combined with compounds

page_text: of vulcanized india-rubber aud gutta percha. The compound when hot may
be rolled out on to fabrics or pressed into moulds without being made into
sheets, and sheets of such compounds may be worked up as other sheet india-
rubber usually is.
The peculiarity of my Invention consists in combining waste vulcanized
india-rubber with gutta percha and sulphur, as herein described.
In witness whereof, I, the said Thomas Forster, have hereunto set my
hand and seal, this Fifteenth day of April, in the year of our Lord
One thousand eight hundred and sixty-two.
THOMAS FORSTER. (L.s.)