IMPROVEMENTS IN THE MANUFACTURE OF PLASTIC COMPOUNDS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Herbert John Haddan at the Office
of the Commissioners of Patents on the 18th April 1882. A communication
from abroad by George Sidney Evans, of New York, United States of
America.
HERBERT JOHN HADDAN of Kensington, Middlesex, "IMPROVEMENTS IN THE
MANUFACTURE OF PLASTIC COMPOUNDS," a communication from abroad by George
Sidney Evans, of New York, United States of America.
The object of this invention is to produce an improved vulcanised plastic compound
suitable for electric insulating purposes, and for application as a water-repellent
coating to fabrics and applicable generally to all purposes for which plastic materials
are used in the arts. This invention consists in treating caoutchouc and gums, such
as gum kauri and gum manilla with palm oil, cocoanut oil, or other non-siccative
oil and vulcanizing the product, in the manner hereinafter described. The following
is a description of my process. I take one hundred parts of palm oil, cocoanut oil
or other non-siccative oil and heat it to a temperature above 212 degrees Fahrenheit
and then add about twenty three parts of caoutchouc, preferably cut into small
pieces to facilitate its solution in the oil. The heat is continued until the caoutchouc
is completely dissolved, the mixture being stirred meanwhile to hasten this result.
When the caoutchouc has become completely dissolved, a resinous gum, such as
gum kauri or gum manilla in a powdered condition and equal in quantity to the
mixture of oil and caoutchouc is slowly added to the mixture, a continued stirring
being maintained for the purpose of mixing the mass thoroughly and rapidly.
I find it advisable for the above operation to employ a temperature of about
350 degrees Fahrenheit. When the above operation has been continued until the
liquid ceases to froth and presents a clear and limpid appearance, the temperature
may be allowed to fall to about 280 or 270 degrees Fahrenheit, although this is not
absolutely necessary. The molten mass is then incorporated with about from five
to fifteen per cent (depending upon the degree of vulcanization desired) of chloride
of magnesium, or such other of the chlorides of the earthy alkalis as will answer
the purpose. The mass is allowed to remain at a high and uniform temperature
for several hours to complete the vulcanization, and the product is improved by

page_text: permitting this heat to continue for as much as 24 hours. At the expiration of the
Lime allowed, the mass is washed several times in hot water to reinove the free
chloride, and finally heated to a point below the decomposing point of the caoutchouc,
to expel whatever water it may contain. The product is then ready for use in the
several arts above stated. Another method is to mix gum kauri, or any of the
manilla gums with palm oil, coconnut oil, or other non-siccative oil in about the
proportion of two or three of the gum to one of the oil, the proportion of oil being
increased according to the hardness of the gum. The mixture is then melted and
slowly heated to about 400 degrees Fahrenheit (with suitable stirring to prevent
burning) for a period of from three quarters of an hour to an hour and a half or
more, until the mixture becomes clear and limpid. After the mixture has been
sufficiently cooked, it may at once be vulcanized, either in the ordinary way or by
having alumina added to it in the proportion of about one sixteenth or more of the
weight of the mixture, after which about one to one and a half per cent of sulphur
or its equivalent is added and heat continued until a antisfactory vulcanite is
obtained. I prefer however, to let the mixture of gum and oil cool after it is cooked,
working in the alumina while it is in that condition, then melting the mixture with
suitablo stirring, then allowing it to cool, then incorporating the sulphur or its
equivalent, and finally heating to vulcanize. The plastic material inado by heating
gums with palm oil, cocoanut oil, or other non-siccative oil is readily soluable in
turpentine and oils, and the solution may thus be applied to cloth or other fabrics
to water-proof them, and may be vulcanized upon the material if desired. The
solution may also be used as a water proof paint.