AN IMPROVED VEGETABLE PARCHMENT AND PROCESS FOR MAKING THE SAME
Year: 1875

page_text: PROVISIONAL SPECIFICATION leby William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on the
22nd December 1875.-A communication from abroad by Ambrose
G. Fell, of the City and State of New York, United States of
America.
'
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "AN IMPROVED VEGETABLE PARCHMENT AND
PROCESS FOR MAKING THE SAME," a communication, to be as follows:-
This Invention consists in a vegetable parchment composed of a
gelatinized fibre, and also in the process herein-after, particularly
described for producing the same. In describing this process I shall
divide it into three parts as follows :-
First. I prepare a solution of twenty-five parts of gelatine and one
hundred parts of water, to which I add two hundred parts of com-
mercial sulphuric acid; in this solution or bath I immerse unsized
paper of any desirable kind, whether made from paper, straw, linen,
cotton, or wood, the paper remaining in the bath from two to three

page_text: It is then
minutes, or until it is thoroughly saturated with the same.
withdrawn and the surplus solution drained from the paper and
returned to the bath, after which the paper is washed in water, or in
some other manner the acid contained in it is neutralized. The paper
then dried, and this completes the first process in the preparation of my
artificial parchment.
is
Second. I prepare a bath consisting of twenty-five parts of gelatine,
one hundred parts of water, and from twelve to fifteen parts of a
compound of tungstate of soda and chromate and bichromate of
potassa, with sufficient glycerine to give any required degree of supple-
ness to the paper. This bath is heated to a temperature of say 180°
Fahrenheit, and in it I immerse the paper which has been subjected to
the first process above described for from two to three hours, or until
the same is thoroughly saturated, the time required to effect this of
course depending upon the thickness of the paper.
Third. In a bath composed of three parts of proto or two parts of
persulphate of iron, and ten parts of water, together with the same
amount of glycerine that it had been found necessary to add in my
second process herein-before described, I immerse the material as it is
received wet from the before described bath named in my second
process. The material after being immersed in this last bath for a
length of time, that will depend upon its thickness, is next dried over
hot or cold calendar rolls.
t.
When the material is required to be soft and pliable the rolls should
he hot and the material dried thereon as quickly as possible.. When
however the material is required to be stiff as for leather, the rolls may
be of the ordinary temperature and the material dried slowly.
The effect of the first bath is to convert the unsized paper into the
ordinary vegetable parchment, except that the gelatine therein used
renders the parchment more open or porous to receive the gelatine and
chemicals named in the second part of my process. In the second
bath the chromic and tungstic acids, by the after action of the third bath
named, precipitate the gelatine in the pores of the parchment in an in-
soluble tough condition, it is rendered flexible however by the glycerine
which is present, the flexibility being rendered permanent by the
insoluble condition of the gelatine.
:

page_text: Although any acid or acid salt would act upon the tungstate or
chromate, liberating their respective acids and thereby precipitating the
gelatine and producing to some extent a similar product, still I find
that the proto or persulphate of iron acts more directly on the gelatine,
and by the formation of chromate and tungstate of iron produces a
stronger and more permanent material, and one more nearly resembling
the natural parchment.
From the process herein-before described an artificial parchment is
produced consisting of a gelatinized fibre that may be employed for all
the purposes for which parchment is now used, and for many of the
purposes for which leather is employed.