IMPROVEMENTS IN THE MANUFACTURE OF VEGETABLE PARCHMENT OR PARCHMENT PAPER
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on the
16th February 1870.-A communication from abroad by Colin
Campbell, of Buffalo, New York, United States of America..
I, WILLIAM ROBERT LAKE, of the "International Patent Office,"
Southampton Buildings, London, Consulting Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF VEGETABLE PARCHMENT OR PARCHMENT PAPER," a com-
munication, to be as follows:-
The said Invention relates to the manufacture of a material analogous
to what is commonly termed vegetable parchment.
To produce vegetable parchment common unsized paper is subjected
to the catalytic action of dilute sulphuric acid, whereby the paper is
changed into an article which in its structure and qualities somewhat
resembles ordinary animal parchment. The greatest care and delicacy
are required in manufacturing the article to determine the requisite
strength of the acid, the temperature of the room, and the length of time
the paper is subjected to its influence. If the acid is not sufficiently

page_text: diluted the material will be charred; if the solution is too weak and the
paper is left too long in it the latter will be partially converted into.
dextrine. Such parchment or membrane after it has become wet and
subsequently dried loses to a great degree its pliancy, becoming, hard
and stiff..
Experiments: have proved that by using sulphuric acid instead of
the dilute acid less care in the manipulation of the process is required,,
and that the acid can be used in a cold state, and the operation may be
earried on in an apartment at any ordinary temperature, while the
article produced is greatly-superior-to-that-made-by-the-usual-method,
as it retains the same desirable qualities after being wet and dried as.
before..
My Invention consists partly in passing paper, sized or unsized,
through a bath of undiluted commercial sulphuric acid or oil of vitrol
and then immersing it immediately in a water bath, whereby I am
enabled to produce a superior article of paper which possesses the
qualities herein-after enumerated. It also consists partly in passing the
paper through an alum bath preparatory to treating it with acid,
the alum preventing the undue penetration and action of the acid. In
the preparatory alum treatment the paper is simply passed through a
bath of alum in solution and then thoroughly dried, when it is ready for
the acid. It may be subjected to the acid treatment during the manu-
facture of the paper with or without the previous alum treatment by
allowing the web after it passes the drying rollers to dip into a tub of
the acid and then into the vat containing the water. I may simply dip
the pieces of paper to be treated in the vessel containing the acid, and
then drop them into a vat of water. The paper is then treated in an
alkaline bath and a subsequent water bath in the usual manner for.
removing the acid.
Written and printed paper can be subjected to treatment by my
improved process without materially affecting the clearness and dis-
tinctness of the letters.