Year: 1888

page_text: 1, THOMAS PRINGLE MILLIGAN, of South Orange, Essex County, New Jersey,
U.S.A., Manufacturer, 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:-
It is a well known fact that glue stock has been heretofore commonly treated to a
digest in the milk of lime for several weeks, then washed and dried.
Unless dried, it was found that the injurious fluids still present in the stock would
come out in the boiling and operate to the partial destruction of the gelatine forming,
and deprive it of the setting quality.
If this process has been properly conducted, the stock when dried may be converted
into gelatine, glue, or sizing, by soaking in cold water and boiling.
The resulting solution can then be chilled, cut into sheets, and dried on nets. My
process differs from the above and all other processes in almost every essential
particular, as will be seen in the following description: and, that each step may be
clearly understood, I will take for illustration my process, as applied to the treatment
of fresh pieces and fleshings from the tanners beam. This stock is as difficult to
prepare as any, and to succeed in producing good results from it, will enable any
one skilled in the art to apply my process successfully to any other kind of glue
stock.
If we now examine this stock we shall find that it contains about three times its
dry weight of water, a large portion of which it has absorbed in the sweating and
lime bath to which it has been treated by the tanner, while still part of the hide.
There is also in this stock (what is found in all green hides) the water of com-
position, which from its acidity and acrid nature, is very injurious to gelatine; a large
percentage of acid grease and tallow, these with a strong trace of lime, must be
removed before the stock will be in proper condition for boiling. As a preparatory
step, 1 first wash the stock clean in cold water. This may be done in a tank or washer
Price 6d l

page_text: made for the purpose, and there being nothing novel in washing stock in cold water,
I do not embrace the preliminary step in my process which may be considered as
commencing with, a shrinking of the stock effected by the action of very hot water,
or by steam.
In using hot water, I place the wet stock in a basket or other vessel, made in
convenient form, of wire, rattan, or other suitable material with interstices, small
enough to prevent the escape of the stock, while sufficiently large to freely admit the
passage of water.
The receiver containing the stock is now conveyed to a tank of water, about boiling
point, and plunged in, the stock almost instantly contracts and hardens, losing about
40 per cent. of watery fluids. Less than one minute is ordinarily required for this
operation, when the receiver may be drawn up and the stock placed on a drainer
ready to be conveyed to the dry loft. In using steam for the shrinking process, I
find that a jet from pipe or steam hose, directed upon a thin layer of stock placed on
a slanting floor is as easy and effective a way as any.
The stock under this treatment acts the same as in the hot water bath, and the
effect produced is precisely the same.
This step of the process may be practiced at the tanneries where the stock is
collected by the glue maker, and results in a considerable saving in the transportation
of the stock to the glue factory, as it greatly improves the condition of the stock for
handling, by hardening the tissues, and diminishes the bulk and weight of the stock
over 40 per cent.
I now convey the stock to a loft heated by steam and properly ventilated, the stock
being exposed to heated air on frames similar to those used for drying glue. The
temperature of the loft to range from 125 to about 170 fr., for this is hot enough to
melt the tallow and extract it from the body of the stock, the high temperature also
changes its nature, so that it may be easily removed by the alkali bath. Good results
however, can be obtained by drying in the open air, and under a summer sun.
The stock being now bone dry, I subject it to the action of an alkali bath at about
boiling point, and for this purpose I prefer to use sol-soda, and if the water is
naturally soft 12 pounds to 100 gallons of water will be found sufficient; if hard, use
a little more. The stock is placed in a receiver (similar to the one described for use
in hot water bath) and lowered into the boiling alkali, where it is left for about ten
minutes, or if stock is very greasy, a little longer; the object being to remove grease
and cleanse the stock from all deleterious matters without injury to the glue yielding
tissues.
The dry condition of the stock permits this to be accomplished thus quickly and
effectually.
I now plunge the stock which is still in the receiver, into a bath of hot water to
rinse off the alkali and any adhering grease, taking it out almost immediately; I rinse
off in cold water and then the stock is ready for a final bath in alum water.
This alum water I prepare by dissolving 10 pounds of alum for every 100 gallons
of water contained in the tank.
The stock is allowed to remain in this bath until hard. This will usually be in
about twenty minutes.
After which I return the stock to the dry loft, if it is to be kept for future use or
sale, and dry it.
at
It will then keep for years and be ready for conversion into gelatine, glue, or size,
any time.
If, however, the stock is to be made into gelatine, glue, or size, immediately, the
second drying is not necessary. In such case, the stock can be taken from the alum
bath and boiled, and a beautiful clear solution will be obtained which will set hard
when cold, and may be cut and dried on nets. It will be seen in following out my
improvement that I first drive out of the stock all injurious fluids, and then by
immersing the dry stock in a boiling alkali bath, the interior of the stock is reached
and acted upon to neutralize any acid substances remaining therein; while the grease
adhering to the exterior of the stock is floated off and removed.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what I
claim is :-
:―
1st. The treatment of glue stock to expel the contained fluids, consisting in the
application to the stock of hot water or steam at a temperature to produce a sudden
contraction of the tissues, substantially as herein set forth.
2nd. The treatment of glue stock to remove the fatty ingredients which consists in
drying the stock at a temperature sufficiently high to melt the tallow contained
therein, and to thus separate the same from the stock, substantially as herein set
forth.
3rd. The immersion of the glue stock in a dry state in a bath of hot alkali, to melt
and disengage the grease adhering thereto, substantially as herein set forth.
4th. The treatment of glue stock to expel the contained fluids and separate the
body of the tallow therefrom, consisting, first, in the application to the stock of hot
water or steam at a temperature to produce a sudden contraction of the tissues, and,
secondly, in drying the same stock at a heat sufficiently high to melt the tallow
contained therein, as and for the purpose set forth.
5th. The treatment of glue stock to fit it for boiling which consists first, in the
application to the stock of hot water or steam at a temperature to produce a sudden
contraction of the tissues, secondly, in drying the same stock at a heat sufficiently
high to melt the tallow contained therein, and thirdly, in immersing such dry stock
in a bath of hot alkali to separate the grease therefrom, as and for the purpose set
forth.
6th. The treatment of glue stock to fit it for boiling which consists first, in the
application to the stock of hot water or steam at a temperature to produce a sudden
contraction of the tissues, secondly, in drying the same stock at a heat sufficiently high
to melt the tallow contained therein, thirdly, in immersing such dry stock in a bath of
hot alkali to separate the grease therefrom, and, fourthly, the treatment of said stock
to a bath of alum water to neutralize the alkali and harden the stock, substantially as
herein set forth.
7th. As a new article of manufacture, dry glue stock saturated with alum, as and
for the purpose herein set forth.
D L 1:1
.. 1
M
1 1000
ALLISON BROS.,
Agents for the Applicant.