IMPROVEMENTS IN THE PREPARATION OF IMPERMEABLE PAPER FOR MANUFACTURING SEVERAL FABRICS OR ARTICLES
Year: 1868

page_text: PROVISIONAL SPECIFICATION left by Charles Monestier and Ivar
Bang at the Office of the Commissioners of Patents, with their
Petition, on the 30th December 1868.
We, CHARLES MONESTIER and IVAR BANG, of Paris (Boulevard
St. Michel, No. 125), Manufacturers, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE PREPARATION OF IMPERMEABLE
PAPER FOR MANUFACTURING SEVERAL FABRICS OR ARTICLES," to be as follows:-
Our Invention consists, firstly, in manufacturing imitation collars,
cuffs, shirt fronts, petticoats, curtains, and other similar articles of
vegetable parchment or of paper or pasteboard that has partially under-
gone the process of conversion into vegetable parchment, and which is
called impervious paper; and, secondly, in the manufacture of lace
paper and that kind of material usually composed of cotton, cloth, or
other similar fabric placed between two layers of paper, pasteboard, or
paper pulp.
It is well known that by soaking unsized paper in a concentrated
solution of sulphuric acid vegetable parchment is obtained, which is

page_text: transparent, stiff, impervious to water, and of a yellowish color. Now
we have discovered that by treating sized paper by the same process a
slight layer of vegetable parchment is deposited on the surface of the
paper, for as the acid cannot penetrate the whole thickness the effect of
the treatment is limited to the surface only. By this process therefore
we obtain a paper only partially converted into vegetable parchment, a
material less stiff, brittle, and transparent, but one which is perfectly
waterproof, and can safely be washed in water with soap, alkalies, and
other cleansing substances. It is this action of sulphuric acid on sized
paper that forms the foundation of our Invention.
We soak sized paper or pasteboard in hydrated sulphuric acid for a
few minutes; we then thoroughly wash it in water, and after that in an
alkaline solution to efface the remaining traces of acid. This alkaline
solution is a more or less concentrated solution of carbonate of soda or
potash, or a solution of caustic soda or potash, or any other solution that is
capable of neutralizing the sulphuric acid that still remains in the paper.
In order to give to the paper thus far manufactured a white and shining
appearance we deposit on its surface a slight coat of mineral white, for
instance, by soaking it in a solution of salts of baryta, by which means
a layer of sulphate of baryta is deposited over the surface. The paper
can also have a blue tinge imparted to it by any known means. From
this paper or pasteboard thus manufactured we cut the imitation collars,
cuffs, and other articles above mentioned, all of which can be washed
and will not be injured by perspiration.
Sometimes we use pure vegetable parchment for the same purposes,
but as it is yellow and transparent instead of treating ordinary unsized
paper with sulphuric acid we operate upon unsized paper that has been
soaked beforehand in a solution either of salts of baryta, lime, or stron-
tian, lead being too dangerous for the purpose. The paper is then dried,
and afterwards soaked as usual in sulphuric acid; the acid converts the
paper into vegetable parchment, and at the same time in mixing with
the above-mentioned salts forms thereon a white insoluble sulphate,
which renders the parchment white and opaque. We can equally well
manufacture these articles of any desired tint by coloring the paper,
either before or after it has undergone the above-mentioned
with
process,
any coloring matter that cannot be decomposed by sulphuric acid, viz.,
any color of aniline, such as fuchsine, for imparting a red tinge to the

page_text: articles, or Hoffman's violet, or any similar compound. Our process
may be applied to paper made of rags, wood, straw, or any other paper
now in use, and when thus treated may be used for lace curtains,
paperhangings, counterpanes, boxes, playing cards, and many other
articles.