IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL HARD AND SOFT INDIA-RUBBER AND GUTTA-PERCHA
Year: 1883

page_text: LETTERS PATENT to William Henry Harrison, of 41 Great Russell Street, in
the County of Middlesex, Author and Journalist, for an Invention of
IMPROVEMENTS IN THE MANUFACTURE OF ARTIFICIAL HARD AND SOFT
INDIA-RUBBER AND GUTTA-PERCHA
PROVISIONAL SPECIFICATION left by the said William Henry Harrison
at the Office of the Commissioners of Patents on the 1st February 1883.
WILLIAM HENRY HARRISON, of 41 Great Russell Street, in the County of
Middlesex, Author and Journalist. IMPROVEMENTS IN THE MANUFACTURE OF
ARTIFICIAL HARD AND SOFT INDIA-RUBBER AND GUTTA-PERCHA
I take cellulose or hydrated cellulose in its cellular or flocculent condition,
avoiding it in its state of fibre or destroying that state in its treatment. In some
cases I take the cellulose from soft vegetable matter before the cellulose has
reached a liquified or passed the cuticular state. Sometimes I take entire soft
land or water plants or grasses or portions thereof, reduced to a syrup or paste,
and completely or partially disintegrate any cuticular tissue therein during some
part of the treatment. Or I take gluten, or hydrated gluten, or one of the
Or I take
compounds into which gluten can be separated by chemical treatinent.
mixtures of two or more of the aforementioned substances, to give flexibility and
tenacity to the final compound.
The flexible vegetable substance selected is brought into a state of solution, or
emulsion, or pasty syrup in a liquid, an preferably one in which it is wholly or
partially soluble; for instance, acetic anhydride diluted or undiluted, and with or
without the application of heat and pressure, is useful for the purpose. Several
other antiseptics are useful.
One or more resins, gum-resins, oils, waxes, fats, gums insoluble in water tars,
bituminous substances, or varieties of pitch, are selected to resist the absorption of
water by the final compound, and to impart to it some of their properties,
according to the use for which it is intended. All other conditions being equal, I

page_text: prefer to select water-resisting substances which are soluble in in the liquid selected
to dissolve or emulsify the flexible vegetable ingredient previously mentioned.
Otherwise they are dissolved in one of their own solvents, or are melted, and are
added to the mixture mentioned in the preceding paragraph, and are emulsified
with it if they still will not dissolve therein.
If the mixture is acid, it is more or less neutralised by the addition of an alkali
or an earth. If it is alkaline, it is more or less neutralised by the addition of an
acid. Or if the acid or alkali in in the mixture be volatile, it may sometimes be
advantageously removed by evaporation or distillation. If the waterproof particles
are fully produced in the mixture, despite the presence of an alkali or an acid, the
latter may be left to be separated by whatever method is adopted to separate the
watery part of the mixture from the waterproof particles in it.
When the watery liquid containing the waterproof particles is not required for
use as it is, the waterproof particles are separated from it, washed when necessary,
pressed or allowed to cohere into a viscous mass, and dried, or may be applied in
any of these stages to various useful purposes.
When desirable, I modify the characteristics of the final compound by, at some
stage of the operations mixing in colouring matter, scent, or an astringent
substance, such as alum, chrome alum, or one of the varieties of tannin, or mixtures
of astringents. Or I add vegetable matter, rich in some astringent. The
characteristics of the final compound are also modified, when desirable, by rolling,
pressing or mechanically manipulating the compound in air or water, before it has
set to its final degree of hardness.
The temperatures of the operations are regulated according to the ingredients
used. With some substances it is a cold and wet process all the way through, as
in the formation of natural india rubber and gutta percha by trees. The
compounds producible as berein set forth, have however a wide range of hardness
and softness.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Henry Harrison in the Great Seal Patent Office on the
1st August 1883.
WILLIAM HENRY HARRISON of 41 Great Russell Street in the County of
Middlesex Author and Journalist "IMPROVEMENTS IN THE MANUFACTURE OF
ARTIFICIAL HARD AND SOFT INDIA RUBBER AND GUTTA PERCHA "
This Invention has for its object Improvements in the manufacture of artificial
hard and soft india rubber and gutta percha.
For this purpose I take gluten or vegetable substance containing by preference
a large proportion of glutenous matter or gelatines preferably vegetable gelatines
and dissolve as much of it as I can in acetic acid which is usually diluted with
water for the purpose especially when the gluten used is dry. I prefer to use
vegetable matter which gives tenacious films of vegetable gelatine and have found
Agar Agar seaweed to be one of the best for the purpose. For instance I take a
solution of Agar Agar seaweed, in acetic acid and water. The acetic acid is of the
strength which becomes solid at 50 degrees Fahrenheit. The strength of the Agar
Agar solution is such as to register 10 degrees on Beaume's hydrometer for liquids
heavier than water at a temperature of 64 degrees Fahrenheit. The water in the
solution is equal in quantity to that of the acetic acid.
To obtain the solution of seaweed I by preference first soak it in water say for
about six hours and take note of how much water it absorbs; I then put the
swelled seaweed into vessel together with acetic acid equal in quantity to the
water absorbed and then raise to about boiling point with occasional agitation and
maintain it at this temperature until the required strength is obtained.
To the seaweed solution I afterwards add resins or gum resins which can be
dissolved in acetic acid or which become soluble in the above solution when
concentrated for example I add to 6 drachms by measure of the above solution of
Agar Agar 20 grains of powdered Cowrie gum, 5 grains of Pistacia gum, 5 minims
of castor oil and 4 minims of Stockholm tar; heat is then applied, also constant or
occasional stirring until an emulsion or solution of homogeneous nature is formed.
I usually continue the stirring and heating till the mixture has assumed about
the consistence of treacle. The temperature employed is about 230° Fahrenheit
but considerable variation is permissible on this point.
In place of the greater part of the water and acetic acid in the solution being
driven off after the addition of the resins or gum resins it may be previously
distilled off.
I regulate the degree of softness or hardness of the final compound chiefly by
the proportion of oil tar or soft greasy substance introduced; different resins or
different samples of resins of the same name generally require different proportions
of the softening material.
I also in some cases modify the nature of the final compound by admixing with
the viscous solution obtained as above described ozokerit or other such like
substance not soluble in acetic acid
The mixing operations already described are performed in a still, and the
evaporated liquid collected in a receiver when it is desired to economise the
latter.
The viscous mixture produced by the preceding operations is then boiled in
water for several hours rolled and put aside to dry. The water may be changed
during the boiling operations and the acetic acid recovered by any known means
from the earlier waters poured off.
After a homogeneous solution or emulsion of the substance has been established
I in some cases wholly or partially neutralise the acid in the compound with

page_text: ammonia. This may be done after some of the boiling in water has been
performed by then placing the compound for a short time in a weak solution of
ammonia in water
When ammonia is added to the homogeneous solution of the resins in acetic acid
when that solution has not become very viscous it sometimes forms a coagulum
and sometimes a milky emulsion of the material under manufacture which may be
boiled down as already stated.
Although I believe it to be best to employ acetic acid to dissolve both the
glutinous or gelatinous matter and the resins or resinous gums which are to be
combined therewith it is not essential that it should be employed as a solvent for
both one only of these substances might be dissolved in acetic acid and the other
added thereto having been if requisite dissolved in a separate solvent or otherwise
obtained in a fluid state.
By using as herein before described one solution only for dissolving or softening
the glutinous or gelatinous matter and the resins or gum resins a more intimate
mixture of the substances is obtained partaking more of the character of a solution
than an emulsion.
By the use also of acetic acid as a solvent for the resins or resinous gums several
advantages are obtained; it is easily got out and recovered-and its use permits
of no more soft oily or greasy matter being added than is necessary to give the
requisite softness.
Having thus described the nature of my invention and the manner of performing
the same I would have it understood that I claim :-
First The manufacture of hard and soft india rubber and gutta percha
substantially in the manner herein before described.
Second Jn the manufacture of artificial hard and soft india rubber and gutta
percha the employment of acetic acid for dissolving or emulsifying the glutenous
or gelatinous matter and the resins or gum resins to obtain an intimate mixture of
these substances.
Third In the manufacture of artificial hard and soft india rubber and gutta
percha the employment of acetic acid for dissolving or emulsifying either one
or other of the above substances prior to the addition thereto of the second
substance.
In witness whereof I the said William Henry Harrison have hereunto set my
hand and seal this First day of August in the year of our Lord One thousand
eight hundred and eighty three.
WILLIAM HENKY HAKKISON (L.S.)