Year: 1888

page_text: A communication from WILLIAM KIEL, residing at Butler, in the County of Morris,
in the State of New Jersey, United States of America.
,I ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.1.M.E. do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement :-
This compound is especially adapted to the manufacture of vessels, receptacles or
other articles used for chemical or electrical purposes, and also of articles now made
of rubber or other plastic materials.
The following is a description of the invention:-The composition consists of the
following ingredients: India-rubber, sulphur and pumice stone, to which is usually
and preferably added oil and beeswax. The exact proportions of the ingredients used
in the manufacture of the composition are not invariable, for the reason that the
proportions and quantities vary with the quality of greater or less elasticity of the
material to be produced; for articles where elasticity is required a smaller quantity
of pumice stone is used, where less elasticity is necessary a larger quantity of pumice
stone is used in the proportions indicated below. It is preferable to use crude rubber
which has been washed only, as it is better adapted to the purpose than rubber
which has been passed between hot rollers.
The quantity of pumice stone to be used, varies in weight from one to five times
the weight of the crude rubber.
It is found that it is not practical to use less than even parts of pumice stone and
crude rubber, or more than five times as much pumice stone as rubber. The quantity
of the other ingredients varies according to the quantity of pumice stone and the
quality of the rubber.
Less sulphur is needed with inferior rubber.
A quantity of sulphur is used equal to one-half of the weight of pumice stone,
when the minimum quantity of pumice stone is used; oil equal to one-fifth, beeswax

page_text: equal to one-twentieth of the weight of the minimuin quantity of pumice stone;
thus for example, with ten pounds of pumice stone to ten pounds of crude rubber of
ordinary fair grade, my correspondent finds the best results obtainable by using
five pounds of sulphur with two pounds of oil and one-half pound of beeswax.
The quantity of sulphur used increases with the quantity of pumice stone and at
the rate of one-tenth of the quantity of sulphur for each additional part of pumice
stone, but my correspondent finds it preferable when using the maximum proportion
of pumice stone to use twice the proportionate weight of sulphur used with the
minimum quantity of pumice stone.
The quantity of oil (in weight) used, is equal to one-fifth of that of pumice stone ;
the quantity of beeswax in weight varies from 0.006 of the quantity of pumice stone;
when the minimum quantity of pumice stone is used, to 0.01 of the quantity of
pumice stone when the maximum quantity is used.
.
It is found useful to mix powdered hard rubber with the other ingredients in
quantity equal or less to the quantity of sulphur used; but this is not necessary.
The solid ingredients other than the crude india-rubber are to be finely powdered
and mixed together with the liquids.
They are then with the rubber to be rolled between heated rollers until the various
ingredients are thoroughly incorporated with each other in a manner similar to that
employed in the manufacture of hard rubber. The compound is then ready to be put
in moulds or otherwise treated to produce any desired form and then vulcanised; the
heat in that process varying according to the nature of the article moulded, or the use
to which it is to be put.
This compound should have in vulcanisation a pressure of from fifty to sixty pounds
during a space of from ten to fourteen hours, according to the quantity of pumice
stone used. My correspondent finds it preferable to gradually increase the pressure
instead of using the highest pressure immediately. The compound, must be kept in
the vulcanizer not less than ten or more than fourteen hours. The best results are
produced with a lower pressure and longer vulcanization.
I have above described the new compound as made of india-rubber, sulphur, pumice
stone, oil and beeswax, but it will be understood that other equivalent ingredients
may be substituted for the oil and beeswax or both or, under certain conditions, such
ingredients may be omitted, the principal feature of novelty and value in this con-
position being the use of pumice stone in a vulcanizable compound as giving thereto
new and valuable properties.
My correspondent has found that by mixing pumice stone with the ingredients
constituting hard rubber, a change takes place in the resulting material during the
process of vulcanization, which is different from the change occurring during the
vulcanization of hard rubber and its other compounds, and by it an article is
produced, which, while it has the same hardness as hard rubber possesses a superior
elasticity and toughness, and resulting greater strength, qualities which as far as my
correspondent knows, no other known ingredient other than pumice stone imparts
to vulcanized plastic compound. In the manufacture of hard rubber it is a well
known fact that hard rubber cannot be vulcanized at one time in thicknesses of over
three quarters of an inch. By using this invention I can, at one time, vulcanize
this material of at least two and a half inches in thickness at one operation, without
difficulty and without failure.
The advantages of this invention over ordinary hard rubber and other known,
vulcanized plastic compounds, are that: It is easier to work than hard rubber or
other compounds and is less likely to ignite during the process of manufacture than
hard rubber and its compounds, and generally the process of manufacture of this
compound is greatly facilitated by the use of pumice stone. It is not affected by the
most intense cold. It will stand a very high temperature, much higher than hard
rubber itself. It burns with difficulty. Its ingredients mix faster and more uniformly
than those of other compounds or even hard rubber itself. It is a tough, elastic and
hard material capable of resisting blows which would crush, destroy or fracture
articles made of other vulcanized plastic compounds. It is non-porous and therefore

page_text: well adapted to be made into vessels or receptacles to be used for holding fluids, and
in particular it is adapted to the manufacture of receptacles for holding acids as it
is capable of resisting their attacks and those of other corrosive substances.
It is a perfect insulating material and in insulating properties is superior to any
other vulcanized plastic compound that my correspondent knows of and even superior
to hard rubber in practical use, as it is more durable than the latter substance.
Furthermore it is cheaper and for that reason articles made of it can be used where
hard rubber and other vulcanized plastic compounds as now manufactured cannot be
applied by reason of their cost. It can with success be made into nearly every kind
of article for which hard rubber is now used.
It is believed that none of the vulcanized plastic compounds now in use have the
certain qualities possessed by this compound, and valuable for the inanufacture of
receptacles or vessels and generally for insulating purposes, for the reason that such
compounds are apt to be either too brittle or too porous or are fusible at too low a
temperature. Vessels made of this compound and intended to be used for chemical
purposes are also more capable of resisting the attacks of acids and of preventing the
percolation of liquids through them, when such liquids are confined therein for any
length of time. This compound is also better adapted for the manufacture of vessels
or other articles which are likely to be subjected to violent shocks or sudden jars
(like a storage battery on a railroad train) for the reason that it is less brittle than
any other plastic compound.
It is not intended to limit the use of this compound to the manufacture of the
particular articles for electrical or chemical purposes, nor does my correspondent
confine himself to the proportions herein indicated, but may vary them as circum-
stances may require, but merely names them to give the best results of his
experiments.
I do not claim in this application any special articles of manufacture made from
this compound such as for instance a receptacle for holding acids to be used as a
battery cell or other similar purposes, and tubes or similar articles made of this
material for insulating electrical wires and conductors for electrical sub-ways, or
other purposes as such special articles are the subject of separate applications for
patents.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what 1 claim is :-
1. The herein described composition of matter consisting of pumice stone, india-
rubber, sulphur, united by vulcanization, substantially as described.
2. The herein described composition of matter consisting of pumice stone, india-
rubber, sulphur, oil and beeswax, united by vulcanization substantially as described.
Dated this 4th day of December 1888.