IMPROVEMENTS IN PREPARING COMPOSITIONS OF INDIA-RUBBER AND OTHER MATTERS FOR FORMING ARTICLES THEREFROM, AND FOR THE COATING OF SURFACES OF LEATHER AND WOVEN AND OTHER FABRICS
Year: 1844

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
FORSTER, of Streatham, in the County of Surrey, Manufacturer, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Sixth day of March, in the seventh year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said Thomas
Forster, Her especial licence, full power, sole privilege and authority, that I,
the said Thomas Forster, my exors, admors, and assigns, or such others as
I, the said Thomas Forster, my exors, admors, or assigns, should at any
time agree with, and no others, from time to time and at all times during the
term of years therein expressed, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed,
my Invention of "IMPROVEMENTS IN PREPARING COMPOSITIONS OF INDIA-RUBBER
AND OTHER MATTERS FOR FORMING ARTICLES THEREFROM, AND FOR THE COATING OF
SURFACES OF LEATHER AND WOVEN AND OTHER FABRICS;" in which said Letters
Patent is contained a proviso, that I, the said Thomas Forster, shall cause a
particular description of the nature of my said Invention, and in what manner
the same is to be performed, to be inrolled in Her said Majesty's High Court
of Chancery within six calendar months next and immediately after the date
of the said in part recited Letters Patent, as in and by the same, reference
being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, 1
Thomas Forster, do hereby declare that the nature of my Invention, and the
manner in which the same is to be performed, are fully described and ascer-
tained in and by the following statement thereof, reference being had to the
Drawing hereunto annexed, and to the figures and letters marked thereon, that
is to say:
The Invention has for its objects the combining india-rubber with shell lac or
other gum, or resins, or bitumens, not soluble in water, and with arseniate of
potash or other mineral preservative of vegetable matter, by the aid of grinding
or mechanical mixing and a proper solution, and using such compositions for
casting or moulding articles, and for making sheets or other articles therefrom,
and also for rendering leather and fabrics waterproof, by applying a coating of
such composition to the surfaces thereof, or between two surfaces thereof.
And in order that the Invention may be most fully understood and readily
carried into effect, I will proceed to describe the means pursued by me.
In the first place, I will suppose that it is desired to make articles by casting
in moulds, such as balls, the legs, arms, heads, or other parts of dolls or figures,
or other articles, in which case the composition of shell lac or resinous gums
will be in large quantities in respect to the india-rubber than when the
composition is for spreading over the surfaces of fabrics or of leather. I take
twenty pounds of india-rubber, cut in slices of about half an inch thick, in a
gum
clean state and of good quality, and ten pounds of shell lac, two pounds of
copal, one pound of asphaltum (sometimes called Jews' pitch), and half pound
of arseniate of potash crushed fine. I melt the gum copal in an iron pot, and,
when melted, I add to it the asphaltum and the shell lac, these two having
been first mixed, and then I add the arseniate of potash; I stir the mixture
with an iron rod until the whole is well mixed, and I pour the mixture on to a
surface so as to produce a thin sheet, which I allow to cool. I put the india-
rubber into a suitable machine for grinding or masticating it, as is well under-
stood, and by preference as hereafter explained, and I gradually mix the
mixture above described, the machine being externally heated with steam to
about one hundred and fifty degrees of Fahrenheit. This composition, whilst
hot, I put into iron moulds, and by screw or other pressers I retain the parts
of the moulds together till the composition therein is cold, when the projecting
fins or edges caused by the moulds are dressed off, and the article thus moulded
in dies or moulds will retain the figure and character given by the moulds. I
it be desired to retain the elasticity of the india-rubber, then less of the other
.ingredients will be employed. The object of using the arseniate of potash is to
preserve the india-rubber, but other mineral preservatives for vegetable matte

page_text: may be used in place thereof, and other gums or bitumens insoluble in water
may be used. When I require sheets or thin threads of a composition of
india-rubber and gum with a mineral preservative, I employ more or less of
the ingredients with the india-rubber, according as I wish to retain more or
less of the elasticity of the india-rubber, and having ground the india-rubber
with the other matters together, as above explained, I place the same in
moulds, and submit the composition to pressure till cold, in the same manner
as india-rubber is now made into blocks, and I cut such blocks into sheets or
other forms, as may be desired. When the composition is intended to render
leather or fabrics waterproof, or to give a smooth finished surface thereto, I
prefer to employ at the rate of one pound of the dark colored shell lac, one
one pound of gum copal, two pounds of asphaltum (Jews' pitch), one pound of
artificial asphaltum (from coal tar), and half a pound of arseniate of potash,
these are to be mixed in the manner above described; and I apply about four
pounds of the mixture to every twenty pounds of india-rubber, and I grind
and mix them in a suitable masticating machine, preferring that hereafter
described, and I mix therewith any suitable solvent of india-rubber, so as to
reduce the composition to a consistency of about that which india-rubber is
usually brought by solutions for cementing purposes, as is well understood;
and I apply this composition to the surface or surfaces of leather, or to one or
both surfaces of cloth or other fabric, to render the same waterproof, and also
to produce a smooth even surface thereon, or I cement to surfaces of fabric or
of leather together with the composition, the composition being spread on to
the leather or cloth in like manner to that now generally well known for
spreading dissolved india-rubber on to fabrics. And it is important to call
attention to the peculiar effect which the rays or light of the sun has on this com-
position, as the effect of such light constitutes an important part of the process
employed by me. It will be found that on submitting a surface prepared with a
composition of india-rubber with the other ingredients, or a sheet of the same,
to the light of the sun for a few hours, the surface becomes smooth, and loses
all its sticking character, and will not afterwards be injured by any heat which
it may be afterwards subjected to by being in the sun and exposed to air, and
at the same time it will be found to resist india-rubber cement and also the
semi-fluid composition itself; hence the composition, when spread on canvass,
calico, or other fabric, becomes highly useful, resembling leather on the surface,
and thoroughly waterproof, and the surfaces of leather are not only rendered
waterproof by having the above composition spread thereon, but the surface
thus obtained gives a very finished character to the leather. And when I wish
to make long sheets of the composition, above mentioned, I first prepare a long

page_text: piece of calico or other fabric by coating it over with the composition, and then
submit it for six to eight hours to the sun's rays, when the surface will not
allow the composition afterwards laid on to adhere; and I apply a coating more
or less thick of the composition to the prepared surface, by means of a guage
or by rollers, in the ordinary manner of spreading a solution of india-rubber,
and I submit the same to the sun's rays, and the coating thus laid on may then
be readily peeled off, and may be cut up for any purpose to which it may be
applicable. If for any purpose I require the composition, when spread on
leather or on fabrics, to be retained in a state capable of having one piece
cemented to another by the semi-fluid composition, then, in place of submitting
such surfaces to the action of the sun's light, I roll up the surfaces and keep
them in the dark till used. The machine or masticating instrument which I
prefer to use consists of two angularly grooved rollers, the angular projections
of one working in the angular grooves of the other, and the two rollers are placed
in a pan, which is heated externally by steam in an external jacket. The
Drawing annexed shews this apparatus or machine. a, a, are the two grooved
rollers, one of them being driven by a steam engine or other power, the other
being driven by the angular projections of the one put in motion entering into
the grooves of the other; and when grinding the ingredients together, I have
found that by applying a small quantity of potash (an ounce in a quart of
water), run into the mill a small quantity at a time, prevents the composition
adhering to the rollers.
Having thus described the nature of my Invention, and the best means I am
acquainted with for performing the same, I would have it understood that I
do not confine myself to the quantities of the matters herein mentioned, as they
may be varied, but I have given what I have found to be the best quantities
for the particular purposes herein explained; and I would state that I am
aware that india-rubber has before been mixed with shellac, and a suitable
solvent to be used as a cement; and I am also aware that india-rubber with
shell lac have been ground together, by what is called masticating, with fibrous
materials, and formed into sheets, and such sheets have been stuck on to
fabrics; and I mention these in order to state that I do not claim the same.
But what I claim is,-
First, the applying or spreading a composition of india-rubber and shell lac,
or other resinous gum or bitumen (not soluble in water), together with a
solvent, and with or without arseniate of potash or other mineral preserver of
vegetable matter, on one or more surfaces of leather and woven or other
fabrics, to render the same waterproof, and for obtaining a smooth and even
surface, as above described.

page_text: gum,
Secondly, I claim the combining such a quantity of shell lac or other
with or without arseniate of potash, with india-rubber, as to produce a com-
position which may be moulded into various forms and retain the desired
figure, as herein described.
Thirdly, I claim the making of sheets of the composition herein described,
by spreading the same on a previously prepared surface, as herein described.
And, fourthly, I claim the grinding and mixing the materials herein
described in a machine composed of two angular rollers placed in a heated
vessel, as above explained."
In witness whereof, I, the said Thomas Forster, have hereunto set my
hand and seal, this Fifth day of September, in the year of our Lord
One thousand eight hundred and forty-four.
THOMAS (L.S.) FORSTER.
AND BE IT REMEMBERED, that on the Fifth day of September, in
the
year of our Lord 1844, the aforesaid Thomas Forster came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Enrolled the Sixth day of September, in the year of our Lord One
thousand eight hundred and forty-four.