Improvements relating to the Manufacture of a Substitute for Leather, Rubber, and other Flexible Materials.
Year: 1898

page_text: Date of Application, 5th Apr., 1898-Accepted, 19th Nov., 1898
[Communicated from abroad by CHARLES CURTIS, of 220, Devonshire Street, Boston,
Massachusetts, United States of America, Gentleman.]
Improvements relating to the Manufacture of a
Substitute for
Leather, Rubber, and other Flexible Materials.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents, 45,
Southampton Buildings, in the County of Middlesex, 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 invention has for its object to produce a substitute for leather, rubber, and
other flexible materials, which shall be less expensive and shall possess inherent
qualities rendering it more desirable for a variety of purposes, among which may
be mentioned use in the manufacture of elastic tires for vehicles, although it is not
my intention to limit my invention hereinafter described to use in the manufacture
of vehicle-tires alone. The invention consists in the improved composition of
matter and in the improvements in the method of making the same, all of which aro
hereinafter described and claimed.
The accompanying drawing represents a sectional view of a vehicle-tire made
from my improved composition.
In carrying out my invention, I take a solution of rubber, such as the ordinary
rubber cement, which preferably contains a small proportion of sulphur.
After thoroughly mixing the rubber cement and sulphur, I add to the mixture
a quantity of dry pulverized chalk. I then take chemical wood-pulp, such as
ordinary sulphite pulp, and after thoroughly drying the same, I beat or
otherwise treat it to render it flocculent, so that the fibres will be practically_
separated from each other, and will not adhere to each other in dense masses of any
considerable size. With the flocculent fibre I mix a mass of the rubber cement and
chalk. The said ingredients are thoroughly mixed, so that the wood fibres are
practically enveloped in and saturated by the cement, the flocculence of the fibres
enabling the cement to gain access practically to the entire surface of each fibre,
it being my intention to avoid an assemblage of fibres lying in contact with each
other, or without an interposed layer or covering of rubber cement, at any part of
the mixture. The mixture is then rolled out into a sheet, and is subjected to
a degree of heat which is lower than that required by the vulcanization of rubber
as usually practised, the preferred degree being about two hundred or two hundred
and twenty-five degrees Fahrenheit. I find that the mixture subjected to heat of
about this degree is sufficiently cured to prevent softening of the mixture or of an
article made from it, by solar heat or its equivalent, this result being due to the
presence of the chalk as an ingredient of the mixture. In consequence of the
relatively low degree of heat employed, the rubber adheres firmly in the completed
article to the wood fibres, so that the tensile strength and toughness of the product
is not weakened as would be the case if the mixture were subjected to a vnlcanizing
temperature of about three hundred degrees Fahrenheit, such as that ordinarily
employed in connection with rubber articles. I have found that when a mixture of

page_text: rubber and wood-pulp is used without the chalk, the rubber requires such a degree
of heat for its proper protection against solarization as to materially weaken the
adhesion of the rubber to the wood fibres, the toughness and tensile strength of the
composition being correspondingly impaired. This difficulty is entirely avoided by
the use of chalk as an ingredient of the mixture. I do not limit myself, however,
to the use of chalk, as any like material which may be found to possess the same
properties will be within the scope of my invention.
The solvent contained in the rubber cement being evaporated, the sheet is left in
a somewhat porous and spongy condition, and is then subjected to pressure to
properly compact and solidify it. This may be accomplished by passing it between
rolls, or in any other suitable way.
I prefer to add a small proportion of lamp-black to the mixture, this
ingredient being preferably mixed with the chalk before the latter is mixed with
the rubber cement.
The preferred proportions of the various ingredients, by weight, when a substi
tute for rubber is desired, are as follows:-
JE

page_text: 2. The improved method of making a substitute for rubber or leather, consisting
in first drying a mass of chemical wood-pulp; scondly, separating the individual
dry fibres to bring the mass to a flocculent state; thirdly, mixing the flocculent
fibres with a mass of rubber cement and a pulverized mineral; fourthly, spreading
the mixture into a relatively thick sheet; fifthly, subjecting the sheet to a degree
of heat which is less than that usually employed for vulcanization; and lastly,
compressing the sheet.
3. A compacted sheet of material consisting of chemical wood fibres uniformly
mixed with and enveloped in a firmly adherent mass of cured rubber and pulverized
mineral.
4. As an article of manufacture, a vehicle-tire composed of compacted material,
said material consisting of chemical wood-fibres uniformly mixed with and
enveloped in a firmly adherent mass of cured rubber and pulverized mineral.
MIT
.
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.