IMPROVEMENTS IN THE MANUFACTURE OF RUBBER COMPOSITIONS
Year: 1884

page_text: TROYIONAL SPECIFICATION.
I, JOHN JOSEPH CHARLES SMITH of Passaic in the County of Passaic and State
of New Jersey, United States of America India Rubber Manufacturer do hereby
declare the nature of said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
RUBBER COMPOSITIONS" to be as follows:-
This Invention consists in producing a vulcanizable composition of India rubber
or Caoutchouc combined with ozocerite, mineral wax or paraffine and sulphur.
I have found that a mixture of mineral wax with caoutchouc and sulphur,
vulcanized, produces remarkably good effects, whether manufactured in the form of
soft, elastic, semi-hard or hard rubber. By thus employing mineral wax or paraffine
as a portion of the body of the composition there is effected a great saving in
caoutchouc, and by the improved process herein described a vulcanized rubber is
produced which in all its forms will possess and retain the softness, elasticity and
strength of pure rubber compound and which is at the same time in many respects
superior thereto. The semi-hard rubber thus produced possessos qualities similar
to those of pliable leather, that is to say, it may be folded, crimped and sewed like
leather, while it is at the same time absolutely waterproof. The soft elastic rubber
made from this composition is also waterproof and retains an exceedingly soft and
velvet-like appearance.
By experiment I have found that paraffino ozocerite or mineral wax when used
to cheapen and improve rubber compounds if it be mixed with caoutchouc and
sulphur alone, will enter into very imperfect combination with the rubber by
vulcanization so that the mineral wax will separate from the compound if the
rubber be subjected after vulcanization to a moderate heat. Compounds thus
formed are also lacking in strength and elasticity. I have discovered that by the
addition of a certain quantity of rosin or resinous substances with ozocerite a
perfect union of the rubber and sulphur with the mineral wax is effected and
a much stronger and more clastic composition produced.
In preparing the composition the ozocerite is first melted with rosin and the
caoutchouc and sulphur added and then mixed in a regular rubber mill when it
is ready for working into articles in the same manner as other rubber compounds.
In vulcanizing steam is preferably employed for giving at the same time the
requisite heat and pressure.

page_text: The proportions of the ingredients and the time of vulcanization are varied
according to the article to be produced, whether soft, elastic, semi-hard or hard
rubber.
Different metallic oxides are employed for varying the colour of the rubber, and
for producing more rapid vulcanization oxide of lead and lamp-black may be added,
or if a cheap black elastie compound is to be produced coal tar equal in quantity
to the mineral wax may be employed.
For electrical insulating purposes a somewhat larger proportion of mineral was
is employed than for a composition intended for ordinary purposes.
Dated this 18th day of November 1884
J. HENRY JOHNSON,
47, Lincoln's Inn Fields, London, W.C.,
Agent for the said John Joseph Charles Smith.

page_text: 1 JOHN JOSEPH Charles SMITHI of Passaic in the County of Passaic and State
of New Jersey India rubber Manufacturer do hereby declare the nature of said
invention for "IMPROVEMENTS IN THE MANUFACTURE OF RUBBER COMPOSITIONS "
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
This Invention consists in producing a vulcanizable composition of india rubber
or caoutchouc combined with ozocerite, mineral wax or paraffine and sulphur.
I have found that the mixture of mineral wax with caoutchouc and sulphur,
vulcanized, produces remarkably good effects, whether manufactured in the form of
soft, elastic semi-hard or hard rubber.
The objects of this Invention are to effect by the use of mineral wax or paraffine
a great saving in caoutchouc and, at the same time, to produce a vulcanized rubber
which in all its forms will possess and retain the softness, elasticity and strength of
pure rubber compounds and be in inany respects superior thereto. Further, by this",
combination I can produce a semi-hard rubber which possesses qualities similar to
those of fine pliable leather, that is to say, it may be bent, folded, crimped and
sewed like leather and, at the same time, be absolutely waterproof.
The soft elastic rubber made by this composition is also waterproof and retains
an exceedingly soft and velvet-like appearance.
I
Most rubber manufacturers use sundry prepared vulcanizable oils to mix with the
rubber to produce cheaper compounds, but such oils can only be used in small
quantities for fear of seriously affecting the quality of the rubber. In my improved
composition however, I can use from 25 to 40 per cent of earth wax or ozocerite or
paraffine with rubber and still produce a compound having for many purposes all
the good qualities of nearly pure rubber compounds and being at the same time in
many respects far superior thereto.
It has been proposed in the manufacture of so called kerite to use ozocorite, cartlı
wax or paraffine with vegetable oils for the purpose of preventing' too quick
vulcanization of the compound. But I am not aware that earth wax has been
used as proposed by me with rubber to produce a composition superior to those
before made.
In my experimenting I have found that paraffine, ozocerite or mineral wax when
used to cheapen and improve rubber compounds, if it be mixed with caoutchouc
and sulphur alone, will enter into a very imperfect combination with the rubber by
vulcanization so that the mineral wax will separate from the compound if the rubber
be subject after vulcanization to a moderate heat. Compounds thus formed are
also lacking in strength and elasticity.
To overcome this objectionablo feature I went through a long series of experiments
and I found that a certain quantity of rosin or resinous substance mixed with
ozocerite would effect a perfect union of the rubber and sulphur with the mineral
wax and thus produce a much stronger and more elastic composition.
The following is the preferred method of preparation of my improved rubber
composition.
1 take one pound of ozocerite, otherwise called mineral wax or earth wax,
paraffine or cerosine, with which I melt from one quarter to one half pound of
common rosin. This compound I then mix with four pounds of caoutchouc and
one pound sulphur in a regular rubber mill and when well mixed it is ready for
working into articles, in the same manner as the other rubber compounds. The

page_text: vulcanization of the articles is preferably effected by steam so as at the same time
to gain the advantage of the pressure of the steam.
For soft or elastic rubber the time of vulcanization is two hours, starting at
235° Fahrenheit for one-half hour and continuing at a heat of 245° Fahrenheit for
the rest of the period.
For semi-hard products the time for vulcanization is three hours at the same
heat.
For hard rubber or vulcanite I use two pounds of sulphur for the above-cited
quantity of caoutchouc and mineral wax compound. The time for the vulcanization
of hard rubber is from seven to eight hours, starting with 235° Fahrenheit, heating
at this temperature for one hour and continuing at 250° to 200° Fahrenheit for the
remainder of the time.
To obtain various colors for the rubber composition I may add metallic oxido for
example such as vermillion, white lead, or oxide of zinc or terra alba.
For rapid vulcanization I may add oxide of lead and lamp black, the proportions
of each not to exceed in weight one-half the quantity of mineral wax used for a
given quantity of the compound.
For a cheap black elastic compound for rubber I use also coal tar equal in
quantity to the mineral wax.
For electrical insulating purposes I use a larger quantity of mineral wax with
the rubber, in about the following proportions: two pounds of mineral wax; one
. pound of rosin; four pounds of caoutchouc; and two and a half pounds of
sulphur; but these proportions may be changed according to the circumstances.
The various rubber products containing my mineral wax and rosin mixture
possess some remarkably good qualities.
The soft elastic rubber possesses as good qualities as does that made of the purest
rubber and sulphur. It is perfectly waterproof and retains all these good qualities
unchanged.
The semi-hard rubber is a product the like of which has not been produced in
the rubber industry. It is very like soft pliable fibrous leather and is absolutely
waterproof.
The hard rubber is also a much finer material than the ordinary hard rubber.
It takes a high polish and can be easily and smoothly cut.
Having now particularly described and ascertained the nature of any said
Invention and in what manner the same is to be performed I declare that what
I claiin is -
First The improved rublier compound consisting of mineral wax or paraffine
combined with rosin, sulphur and rubber substantially as herein before described.
Second-The improved mode of making rubber compounds, consisting in first
melting together rosin and ozocerite or similar material and mixing this compound
with caoutchouc and sulphur in about the proportions mentioned and vulcanizing.
Dated the 22nd day of January 1885.