The Washington herald., 1907-10-06
WATERPR00FING PAPER.
Operations In Parchmentizing Pa
per-ChcmicuI Effect Remarkable.

Operations Ia ParchmentfzinE Pa
per-ChcmicuI Effect Remarkable.
There has been considerable study of
late years in Germany on the method Of
| treating paper, in its various forms. so
as TO increase it's usefulness for various
| industrial and household purposes.
/ United States Consul Norton says there
are several methods now in vogue in
I Chemnitz for rendering paper and paste
board waterproof which might advan-
/ tageously be utilized in the manufacture
of paper and cellulOse vessels. One, es-
/ pecially applied 20 cellulose. consists in
/ treating the sheets with hot mixture
/ Of asphalt, turpentine, and linseed oil
solution Of glue. Another consists Of
| saturating celluIose articles in a solution
of rosin in a mixture of petroleum, lin
! seed oil, and parafin oil. Solutions Of
varnish in hnseed oil are likewise en-
ployed for rendering surface water
proof
! A process which has given good results
/ is the following: Articles Of paper or
IceIlulose are soaked thoroughly in a So
luton OF rosiE soap. They are then i'm
/ mersed in a hot bath Of zinc chloride.
passed between rollers. are well washed
/ dried in a hot room. treated with paraffin
/ OIL and finally run through a calender
/ The resultant products are strong. .Cugh,
and pliable
| A waterproof pastebOard is secured by
immersing sheets Of ordinary paper in a
| bath Of nitric acid or the solution Of a
nitrate placing the sheets one on top Of
=.
/ heavy pressure. Experimental methods
based upon the fundamental principle Of
| changing paper into vegetable parch-
ment promise the most success in this
/ field. Waterproof cardboard has already
! been manufactured by pressing tightly
| together freshly prepared sheets of the
vegetable parchmen; befoEe being dried
/ The operations in parclUentizing
paper. like those in tanning. a essen
/ TALLY chemical. and effect a remarkable
/ change in physical properties. When
/ carried out with partly diluted sulphuric
! acid (tWO parts Of 60 degrees 10 one part
wateT) sheets OF pure cellulose paper are
/ immersed for a few seconds In the liquid,
/ then thoroughly washed in water, dipped
/ in an alkaline solution ammonia or sodi-
um carbonate) and washed again.
/ This brief treatment sufices 20 bring
| about the following changes: The thick
/ ness OF the paper decreases from 81 to g
per cent Its specific weight increas ases
/ in the same ratio. The strength IS tripled
and even QuadrUpled. There Is a notable
/ increase in homOgeneity and transpar-
/ ency. The product is unaffected and dis
/ integrated, as in the case with ordinary
/ paper while 1t has an increased affinity
/ for tinctorial substances
/ Chemically the brysf exposure to the
action of sulphuric acid has changed the
I exterior Of the CeuulOse hbeTS 10 a gelat-
/ inOus mass, the so-called amyloid. inter
mediary between celluloSe and dextrln.
! This gelati0us amyloid binds the fbers
/ SO closely and intimately together that
/ they form a continuous mass. which. be-
/ ing totally insoiuble, constitutes water
proof substance.
/ With the microscope IL is easy 10 see
| that parchment IS a sheet of ceIlulose
/ hbers. each one Of which is covered by
/ the thin transparent coating Of amyloid
/ the interstces OF pores likewise being
/ completely filed with the same sub
/ stance. II is essentially a surface ac-
! ton which has taken place Ideal con-
/ dltiOns Of success are relative thinness OF
/ the paper employed and a complete alb
sence therein of sluey substances and
mineral matter. Sulphuric acid can be
/ replaced by an aqueous solution Of zinc
/ chloride or an ammOniacai solution OF
cuprous oxide.
/ In order 10 render paper vessels water
| proof, the essential features OF the parch-
mentiziHg might be applied 10 their ex-
/ ternal surface This would involve no
material increase in the strength of the
entire mass.