IMPROVEMENTS IN THE MANUFACTURE OR PREPARATION OF PAPER, CLOTH, OR THE LIKE, FOR TRACING PURPOSES
Year: 1881

page_text: LETTERS PATENT to Walter Thomas Harvey, of 323, High Holborn, in the
County of Middlesex, for an Invention of "IMPROVEMENTS IN THE
MANUFACTURE OR PREPARATION OF PAPER, CLOTH, OR THE LIKE, FOR
TRACING PURPOSES."
PROVISIONAL SPECIFICATION left by the said Walter Thomas Harvey at
the Office of the Commissioners of Patents on the 9th May 1881.
_WALTER THOMAS HARVEY, of 323, High Holborn, in the County of Middlesex.
"IMPROVEMENTS IN THE MANUFACTURE OR PREPARATION OF PAPER, CLOTH, OR
THE LIKE, FOR TRACING PURPOSES."
This Invention consists essentially in thoroughly permeating the paper or other
material with boiled linseed oil or other drying oil. This permeation is easily
effected as the capillary attraction of the paper or linen causes it to absorb the oil
readily upon mere contact. In carrying my Invention into practice in a small
way I spread the oil on with a brush, sponge, or the like, or I may dip the material
in a bath of the oil in a large way by means of spreading rollers clad with felt and
supplied with oil from a reservoir, or by some other of the usual methods of
treating paper, cloth, and similar materials in sheets, long lengths, or rolls.
All drying oils, however, being usually a long time in drying, I find it well to
expedite this process as well as to give a better effect by mixing with the oil spirits.
of turpentine, benzole, or other volatile oil solvent.
This solvent in evaporating apparently carries away with it all the non drying
portions of the oil. The quantity of the solvent as compared to the oil may vary
from a mixture of equal quantities down to no solvent at all, depending entirely
upon the circumstances of the case.
I find also that I can improve the material by washing it after it has been treated,
in water by preference warm, though I may use it at other suitable temperatures,

page_text: this washing causing it to take colours, particularly water colours, and ink better
than before.
When desired, particularly in large works, arrangements can be made for con-
densing the volatile product. For further use, and when saturated with non drying
oil, the solvent may be carefully distilled in vacuo so as to separate it from the
impurity and save the latter as an oil or grease.
"
When "tracing cloth or linen is wanted, size or other suitable transparent
stiffening agent is added to stiffen it, and after drying if desirable it is passed
between polished metal rolls, strongly pressed together, and preferably heated inside
with steam.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Walter Thomas Harvey in the Great Seal Patent Office on the
9th November 1881.
WALTER THOMAS HARVEY, of 323, High Holborn, in the County of Middlesex.
"IMPROVEMENTS IN THE MANUFACTURE OR PREPARATION OF PAPER, CLOTH, OR
THE LIKE, FOR TRACING PURPOSES,"
The present state of the art in the manufacture of tracing paper is ably expressed
in Karmarsh's Technology, 5th edition, volume 2, page 1499 and 1118. In this
there are 6 receipts given for making tracing paper. The first of these is based on
the principle of filling the pores of the paper with a resin which had previously
been dissolved in a volatile solvent. There are many receipts for doing this, some
using Canada balsam, others gum damar, and indeed gum resins of all kinds, and
this is the ordinary way in which tracing paper is made. The nature of resin
however is to get brittle and more opaque with age. The second receipt is similar
to the first, except that solid fatty matters are added, which while making it
tougher and more transparent prevent the paper from taking ink or water colors.
The third receipt consists in oiling the paper with poppy seed and other varnish
oils. These oils beside being very expensive are also of a greasy nature, and the
paper while very useful for oil transparencies is useless for water colors. The
fourth receipt is for oil varnish diluted with benzine and boiled, and had these
been the only things used with the paper it would be very like my Invention
hereafter described, but the boiling of the oil and the mixing it with benzine are
for a very different purpose, for protoxide of lead is added and the boiling is
simply to make the oil combine with the oxide of lead to make lead soap, the
benzine being employed to keep the mass liquid while boiling and combining.
This lead soap is pressed into the paper. Just as common soap is a very different
thing from the grease it is partly made from, so is this soap paper (in which benzine
has been employed to keep the soap liquid so as to permeate the paper) a very
different thing from paper oiled with drying oil and purified with benzine without
being saponified at all. This paper is a stiff, hard, but very transparent material.
The fifth receipt is for a combination of the oil and the resin processes, so it is
needless to describe it further. The sixth, for a combination of the soap, the oil,
and the rezin processes. This, like all saponaceous paper, expands or contracts,
and goes more opaque when wetted. In all, either a brittle resinous paper, a greasy
paper that will not take water colors, or an expensive saponaceous paper made by
the aid of heat is made. Tracing cloth is now universally made by closely pressing
matters soluble in water into the pores of the cloth, and then polishing, a very
expensive plan, and bad in that I cannot wet it with water colors or water without
it loses its consistancy.
Now my tracing paper is tougher and cheaper than any of these, and both it
and my cloth will at the same time take oil, ink, or water color, and can be printed
on like ordinary paper. My Invention consists:
First. In treating the paper with an oxidysed oil, such as boiled linseed oil, so
changed by boiling or oxidation as to change on drying like linseed oil into a
solid non-greasy substance.
Second. In assisting this change and aiding the evaporation of all remaining oily
matter by adding to the boiled linseed oil a volatile solvent such as benzine that
shall fly off, carrying the true oily matters with it. It is not material however,
that the benzine should be mixed with the drying oil, it will do quite as well if
the paper treated with the boiled oil and partially dried is wiped over with benzine
or other solvent, the sole or chief use of the benzine being to carry off with it the
non-drying oil.

page_text: In large works the benzine vapours can be collected and condensed for further
use by drying in closed chambers and refrigerating the fumes, and when largely
contaminated with oil the benzine can be carefully distilled at the lowest
temperature at which it will distil at all. The oily matter is then left
behind.
When I require that the tracing paper should be bleached I treat it in the
following manner:-I wash the tracing paper so formed with a solution of chlorine
in water, say, one of the saturated solution to seven of water for thin paper, and to
one of the water for very thick paper, and before the paper dries again I wash it
with the peroxide of hydrogen. The chlorine makes it tasteless and odourless, and
the peroxide of hydrogen removes the odour of chlorine, bleaches the paper, and
finishes the washing. In actual practice in a small way I mix the boiled linseed
oil and benzine in any proportion from equal weights to all linseed oil, according as
I want to hurry the process and wish to secure perfectly greaseless paper or
otherwise. I lay the oxydysed oil on with a brush or sponge, or in large operations
by spreading rollers.
When making tracing cloth I well starch or size the cloth and then wet each
side with the linseed oil and benzine, and when dry pass it between ordinary
heated polished glazing rolls, and burnishers to glaze it. The paper, and in some
cases the cloth, I not merely use as tracing paper or cloth, but also for wrapping
paper to wrap up foods, chemicals, or tobacco. Its nearly waterproof and transparent
qualities admirably fitting it for these purposes.
Having now described my Invention, and the best modes known to me of
carrying it into effect, together with my latest improvements, I wish it to be
understood that what I believe to be new and desire to protect under the herein-
before in part recited Letters Patent is,-
First. The manufacture of tracing paper by treating it with boiled linseed or
other pure drying oil without saponification, so as to form a paper that is neither
greasy or soapy, but capable of taking water colors with facility.
Second. The use of benzine or other volatile solvent of oil to remove the
last traces of unchanged or non-drying oil from the paper, substantially as
described.
Third. As a new article of manufacture a tracing cloth formed of cloth impreg-
nated with glazing medium insoluble in water, substantially as described.
Fourth. As a new article of manufacture a transparent paper formed of any
ordinary kind of paper toughened and made transparent with boiled linseed oil,
substantially as aud for the purposes described.
In witness whereof, I, the said Walter Thomas Harvey, have hereunto set
my hand and seal, this Eighth day of November, in the year of our Lord
One thousand eight hundred and eighty one.
WALTEK THOMAS HARVEY. (L.S.)