IMPROVEMENTS IN THE TREATMENT OF CRUDE INDIA-RUBBER, GUTTA PERCHA, OR OTHER VULCANIZABLE GUMS, AND IN THE MANUFACTURE THEREFROM OF WHAT ARE USUALLY CALLED HARD RUBBER ARTICLES
Year: 1858

page_text: TTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in
the County of Middlesex, and of 166, Buchanan Street, in the City of
Glasgow, North Britain, Gentleman, for the Invention of "IMPROVEMENTS
IN THE TREATMENT OF CRUDE INDIA-RUBBER, GUTTA PERCHA, OR OTHER
VULCANIZABLE GUMS, AND IN THE MANUFACTURE THEREFROM OF WHAT ARE
USUALLY CALLED HARD RUBBER ARTICLES."-A communication from Austin
G. Day, of Seymour, Connecticut, United States of America.
Sealed the 7th December 1858, and dated the 13th August 1858.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson'
at the Office of the Commissioners of Patents, with his Petition, on the
13th August 1858.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North
Britain, Gentleman, do hereby declare the nature of the said Invention for.
"IMPROVEMENTS IN THE TREATMENT OF CRUDE INDIA-RUBBER, GUTTA PERCHA, OR
OTHER VULCANIZABLE GUMS, AND IN THE MANUFACTURE THEREFROM OF WHAT ARE
USUALLY CALLED HARD RUBBER ARTICLES," a communication from Austin G. Day,
of Seymour, Connecticut, United States of America, to be as follows:-
This Invention relates, first, to an improved system or mode of removing.
bark, sticks, sand, sap, and other foreign matters from crude india-rubber,

page_text: gutta percha, or other vulcanizable gums, the presence of which interferes
with and influences the time and temperature employed in the vulcanizing
process. In carrying out this portion of my Invention, so as to reduce crude
rubber to a common standard for manufacturing into various articles, the
crude rubber or other similar gum- to be subsequently vulcanized is reduced
or cut into slices by rotatory disc cutters in the form of a circular saw, water
being allowed to drip over it during the cutting process. The slices are then
passed between toothed rollers running in water, which rollers stretch and
pinch the material, and wash it at the same time. The material is next
transferred to an exhaust cylinder and charged with a solution of caustic
alkali, when the air is exhausted from the cylinder to remove foreign gases
and vapours, and atmospheric pressure is again let in, to bring the alkali into
close contact with the foreign matters contained in the gum, and aid in
releasing the same therefrom. The material is now transferred to the rollers
again, where it is repeatedly pressed, crimped, and washed, to remove the
alkali, when, it is finally taken to a drying chamber for the purpose of being
dried and seasoned.
The second portion of this Invention consists in mixing and grinding
together two parts by weight, or thereabouts, of rubber or other vulcanizable
gum, previously cleaned as herein-before described, with one part by weight of
ordinary flour of sulphur, into what is usually called the plastic state. The
previous.cleaning and preparing operation is such that it reduces the crude
gums of commerce to a common standard of character, so that East India,
African, and South American rubbers may be all used in the making of hard
rubber manufactures. The peculiar character of this composition depends on
the fact that no foreign earthy or other matter is mixed with the rubber or
sulphur. To, vulcanize into a hard elastic rubber, it will require from sixteen
to thirty hours, commencing at a temperature of about 275° Fahrenheit, and
running up to 320°, or thereabouts, whilst the Hancock composition vulcanizes
within an hour, and the Goodyear within six hours.
It may be here stated that the pure sulphuret of rubber obtained according
to this Invention is an entirely different compound, and requires different
treatment in vulcanizing from the sulphuret mixed with foreign matters as
have been hitherto employed.
The third portion of this Invention relates to a mode of producing an a
artificial circulation of heat in the steam heater.
The goods or articles to be vulcanized, previously covered over with some
pulverulent matter, aro enclosed in a strong iron cylinder, and a current of
steam is introduced, the heat being raised gradually from 275° Fahrenheit to

page_text: 300° or 320°. But it has been found in practice that the vulcanization made
at these high temperatures is not uniform in all parts of the heater, owing to a
want of uniformity of heat therein. To obviate this difficulty, it is proposed
to establish an artificial current by connecting the two ends of the cylinder
by an external pipe, in the centre of which pipe is placed a forcing and
exhausting pump, or a rotatory fán, or other equivalent apparatus worked by
steam or other power, so as to exhaust the air and steam from one end of the
cylinder and force it into the other end. This arrangement ensures a free
circulation and equable heat throughout the interior of the heater.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson in the Great Seal Patent Office on the
12th February 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex, and
of 166, Buchanan Street, in the City of Glasgow,, North Britain, Gentleman,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of August, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the.
said John Henry Johnson, Her special license that I, the said John Henry
Johnson, my executors, administrators, and assigns, or such others as I, the said
John Henry Johnson, my executors, administrators, or 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 THE
TREATMENT OF CRUDE INDIA-RUBBER, GUTTA PERCHA, OR OTHER VULCANIZABLE GUMS,
AND IN THE MANUFACTURE THEREFROM OF WHAT ARE USUALLY CALLED HARD RUBBER"
ARTICLES," a communication from Austin G. Day, of Seymour, Connecticut,
United States of America, upon the condition (amongst others) that I, the
said John Henry Johnson, by an instrument in writing under my hand and
seal, 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.

page_text: NOW KNOW YE, that 1, the said John Henry Johnson, 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, reference being had to the accompanying Drawings, and to the
letters and figure marked thereon, that is to
say:
The said Invention relates, firstly, to the process of cleaning the crude
rubber or other vulcanizable gums, for which Letters Patent were granted to
mne on or about the Seventh of August, One thousand eight hundred and fifty;
five, No. 1787, but which process has since been modified and improved.
That Invention was described as a peculiar system or mode of treating
caoutchouc and other similar gums in the raw state, for the purpose of entirely
freeing such gums from dirt and all foreign bodies, and of removing therefrom
the noxious gases. The Specification stated in substance that the raw gum
is first cut or torn by any suitable machinery into small shreds, and is then
washed in the ordinary way. It has since been ascertained that instead of
treating the article in the above manner, it is a great improvement to pass it
in pieces of from six to ten or even thirty pounds weight. through a pair of
tooth rollers of a particular kind abundantly supplied with water. The Speci
fication also described the air exhausting apparatus and the pumps as confined
to exhausting the air without using any pressure above the ordinary atmo-
spheric pressure by means of the apparatus. But it has since been ascertained
that using alternate exhaustion and extra pressure beyond that of the atmo-
sphere has great practical advantages in forcing the alkaline liquor into the
interstices of the crude gum, and thereby bringing the liquor in contact with
the foreign bodies more extensively than would otherwise be possible to
accomplish. The said former Specification also described the preparation and
use of caustic alkali for cleansing the raw gum, but it has since been ascer
tained that carbonated alkali may, in many cases, be substituted for the caustic
alkalies, and in the majority of cases the cominon carbonate of soda and
carbonate of potash, the one or the other, may be substituted for the caustic
alkali. The first step in my improvements upon the cleaning process, patented
by me in One thousand eight hundred and fifty-five, as above. referred to,
consists in the method of reducing or disintegrating the crude commercial gum
by passing it in pieces of from six to thirty pounds weight between toothed
rollers, by which the gum, instead of being cut into shreds as described in the
Specification of the aforesaid Patent, is drawn out into .long sheets. or webs,
the rollers being plentifully supplied with water, which washes out and
removes most of the earthy and much other foreign matter. Without entering
into a description of any special form or arrangement of rollers as a novelty in

page_text: themselves, I may observe that any toothed rollers arranged either in pairs or
otherwise, the one travelling a little faster than the other, and a space of a:
quarter of an inch, more or less; being allowed between their peripheries, will:
answer the purpose of breaking down' and "sheeting," as it is called by the
workmen, the crude gum preparatory to the second step of the cleaning
operation, that is to say, the exhausting or alkaline treatment. Under the
before named Patent granted to me in One thousand eight hundred and fifty-
five, I only used exhaustion in connexion with the usual pressure of the
atmosphere, but I have since ascertained that when to such alternation of
exhaustion and pressure of the atmosphere there be added to the pressure of
the air within the cylinder some two or three or even more atmospheres, that
is, some thirty, forty-five, or more pounds of additional pressure on the square,
inch, and operating the alternate exhaustion and pressure by several repetitions,
though one repetition may generally answer the purpose, that the liquid more
readily finds its way to the finest pores of the crude rubber or other gum than
it could when using only exhaustion, as described in the Specification aforesaid.
The additional pressure here referred to and described may be had by leaving
or allowing a small space in the upper part of the exhausting cylinder to be.
filled with air, first closing all the stop-cocks leading to it, and then working
the force pump (used to force in liquid) till the pressure within shall be
sufficient to force the liquor into the smallest cavities of the gum. The same
result may be obtained by forcing air into the cylinder after the first ex-
haustion producing the additional pressure by means of the air force pump,
or any other equivalent apparatus. The devices, used to effect the alternate
exhaustion and compression are well known, and need not be particularly
described. In the use of the carbonated alkali in place of the caustic alkali
described in the Specification aforesaid, I would remark that when caustic
alkali is used, the strength need not be greater than 12° to 20° Baume's
hydrometer, but when carbonated alkali is used as a solution of sal-soda
(carbonate of soda), the strength should be 15° to 25° Baume's hydrometer.
The material having been treated in the manner above described, is transferred
to the toothed rollers again, where it is repeatedly pressed, crimped, and
washed to remove the alkali, after which it is finally taken to a drying
chamber, for the purpose of being dried and seasoned.
The second part of this Invention relates to what are usually called hard
rubber manufactures, by way of distinguishing them from the more common
india-rubber goods, which are soft and flexible. This part of the Invention
embraces three points, videlicet, a composition of matter, a process of heating,
and a circulation in the heater: Ilard compounds are generally made from

page_text: rubber, sulphur, and some earthy or oxide base, such has lead or lime. Some-
times the rubber ingredient is dispensed with, and its place supplied by an,
equivalent proportion of gutta percha or jintawan, or other vulcanizable gum;
and it has been found that in nearly all the articles composed of the vulca-
nizable gum and sulphur united with some eathly or other base, the com-
position is liable to become brittle, and thus be diminished in value.
To remedy this evil, it is proposed to employ a new composition of matter,
the manufacture of which requires a special method of operating. This com
position is composed as follows:-Having thoroughly cleaned any of the crude
gums of commerce, whether caoutchouc, gutta percha, jintawan, or other
crude gum, I mix the purified gum with sulphur, in the following pro-
:-
portions -
If the gum be Para rubber, I mix 1 lb. of rubber with 8 oz. of sulphur.
East India
Grayaquil or
Carthagena
"
1 lb.
"
1 lb.
. "
"
8-10
6-8
"
The last two being a harder species require less, while the East Indian and
African being soft require more sulphur than the Para article.
The mixture may be prepared in any of the modes of mixing the gum and
sulphur known to manufacturers.
In all cases where india-rubber proper is used the Para article is the one
referred to as the standard by which to compare other gums. But the medium
proportion of the ingredients is, gum 1 pound and sulphur pound. The gum
and sulphur being thoroughly mixed, and the articles to be manufactured duly
formed, they are placed in a steam chest or heater, usually made of cast iron,
and of suitable size to contain the articles to be vulcanized, and of sufficient
strength to resist the internal pressure of steam at a heat of 275 to 310 degrees
of Fahrenheit's thermometer, or thereabouts, as supplied from any convenient
boiler, and let in upon the goods, which are protected in dust, or in any other
way known to workers of hard compounds.
Before stating the details of running the heat, I would observe that that
the time and degree of heat are to be considerably varied with the size or
thickness of the goods to be heated, growing out of some of the phenomena of
vulcanization. Thus, it has been ascertained that the union of perfectly pure.
rubber and sulphur takes place in such compositions, as claimed herein, very
slowly, and at a very high degree of heat only, and that during the whole time
in which the materials are combining, a continued discharge of sulphuretted
hydrogen and sulphuret of carbon is found to take place through the dense
pores of the articles, and the thicker the articles, to be vulcanized the greater.

page_text: the heat, and the longer the time required to expel the eliminated gases. As
the pores of the compound are exceedingly fine, and the escape of the gases
proportionally slow and difficult, whilst in a vulcanizing compound containing
an earthly base, the base itself furnishes porosity, and consequently easy escape.
of gases; hence, it requires less time to vulcanize and less heat, but at the
same time the product has less toughness and strength, and morcover become
brittle by age. The composition of gum and sulphur having been fixed upon,
the time and the degree of heat must be adapted thereto, to produce the
article sought; therefore the composition of matter, the time of heating, and
the temperature constitute a new and distinct progress.
The following are examples of the details of running the heat, showing
the range of temperature and time required for vulcanizing this composition.
of matter.
In the first case the articles are supposed to be, say, a quarter of an inch in
thickness, and to require ten hours for vulcanizing.
1. The heat is run directly to
then to
275° for 4 hours,
280°
2
"
"
"
"
"
"
290° 2
"
- 295°
-
300°
-
305°
دو
39
1
33
".
33
I
33 2
"
2. Articles five-eighths of an inch in thickness, time 13 hours.
Heat run directly to
275° for 6 hours,
"
required for vulcanizing hard gum compound, but I do not mean to confine,
my process to the exact steps, nor to the exact temperatures, nor yet to the
precise length of time, so long as I embrace the higli range of temperature.
and the prolonged time beyond what has been hitherto attempted.
It has been found by experience in the hard gum manufacture, that it is
exceedingly difficult to maintain a uniform temperature throughout the heater,

page_text: during the progress of vulcanizing; articles in one portion of the apparatus
will be cured too much or burnt, whilst those in another part will be cured too
little! These iniperfections I have greatly obviated by establishing an artificial
circulation-in the heater, which equalizes the temperature in every part of it.
This may be done by means of a double-acting pump, or a rotatory fan, or other
equivalent device, which shall draw out the steam and air-from one end of the
cylinder, and transfer the same into the head of the opposite end; as shewn in
the accompanying Drawing, which représents à longitudinal section of an
ordinary heating cylinder lying on its side. A is the heating cylinder, which
is supplied with steam for heating it under pressure, by ineans of the pipe B.
The articles to be, heated or vulcanized are placed in A, and supported on
suitable. iron trays. resting on iron rails, and designed to be run in and out
thereon. The circulation for the purpose of equalizing the temperature in all
parts of the heater is made by working the pump C.or its equivalent, which
draws the ariel contents from the end a of the heater through the valve D,
and forces it through the valve E and pipe F, whence it strikes against the
head G, and is distributed through the perforated plate H, and thence through
the body of the cylinder.
"
It is evident that a single-acting pump or a double-acting pump or a rotatory
pump or a fan could be used for this purpose. I do not claim any special
form of apparatus, as a variety of apparatuses might be used, and perhaps
equally well. Even a current of steam forced in at one end and out at the
other would aid in equalizing the heat, although imperfectly.
:
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion
to describe or refer to, as variations may be made therefrom without deviating
from the principles or main features of the said Invention; but what I con-
sider to be novel and original, and therefore claim as-the Invention secured
to me by the herein-before in part recited Letters Patent, is,-.
First, the general system or mode of treating crude india-rubber, gutta
percha, or other vulcanizable gums, and the manufacture from gums so treated
of hard rubber articles, as herein-before described.
⚫ Second, passing the crude gum in' masses of from ten to thirty pounds
weight through toothed rollers having a slipping motion, in the manner and
for the purpose herein-before described.
Third, the application and use of alternative pressure and vacuum in the
cleansing process of raw gums, as herein-before described.

page_text: Fourth, the mixing and grinding together of two parts or thereabouts by
weight of caoutchouc or gutta percha, or other vulcanizable gum, and one part
of sulphur, when such composition is preparatory to the running of the heat,
as herein-before described.
Fifth, running the heat for vulcanizing flexible and elastic hard gum com-
pounds from a temperature of about two hundred and seventy-five degrees
Fahrenheit, at the commencement of the process, and carrying the same up to
three hundred degrees and upwards, as herein-before described.
Sixth, equalizing the temperature in the heating apparatus by mechanical
means, substantially as herein-before described.
In witness whereof, I, the said John Henry Johnson, have hereunto set
my hand and seal, the Eleventh day of February, One thousand eight
hundred and fifty-nine.
J. HENRY JOHNSON. (L.S.)