CASTOR-OIL INDUSTRY. 39 
Among other uses in the rubber industry, castor oil finds application 
in the manufacture of gas tubing, insulating tape, and packing sheets. 
Cellulose nitrate ‘‘dope’’ is greatly improved by the addition of 5 
to 7 per cent of castor oil or treated tung oil. Greater elasticity of 
film and slow evaporation result. 
Castor oil lends elasticity to varnish and has been stated to be an 
ingredient in certain artificial skin preparations, the formula for one 
of which is shellac, 1 part; alcohol, 3 parts; castor oil, one-fifth part. 
It is also used in retouching varnishes and in photographic-negative 
varnishes. In general, its use in varnish is to lessen brittleness and 
minimize the attendant property of chipping and peeling. 7 
Castor soap is transparent, white, and quite hard. It dissolves in 
cold water without rendering the latter turbid. It lathers quickly 
and is very soluble. 
In the manufacture of tire cement castor oil forms an ingredient of 
good thick shellac varnish. It prevents the bicycle rim from becom- 
ing hard and brittle. 
-Many salts of the aniline series are soluble in castor oil and advan- 
tage has been taken of the fact to prepare typewriter inks of great 
copying power, which permit large numbers of copies to be taken 
from the same impression. Hopkins! states that such inks are very 
little affected by extremes of dryness, moisture, heat, or cold. He 
also states that the oil-soluble colors are not affected by the moisture 
of the hand. Castor oil also prevents the ink from drying on the pad 
and at the same time ‘‘bites’’ the oil-soluble aniline color into the 
paper and prevents it from rubbing. Objection, however, to the 
use of the oil is that impressions from such inks are often surrounded 
by greasy marks caused by the fats spreading in the pores of the paper, 
and that the present practice is to.make most of the stamping inks 
without grease by preparing mixtures of coal-tar dyes in glycerin. 
In the manufacture of fly paper castor oil is a necessary ingredient. 
Various combinations of castor oil, resin, and other products are 
spread upon heavy paper with a common glue sizing. It is stated 
that sugar is sometimes used to make the product more attractive. 
By heating nitrated oils to 130° C. or by oxidizing them with lead 
peroxid, rubberlike substances are obtained. Nitrated castor oil, 
made by nitratmg with a mixture of 2 parts sulphuric acid and 1 
part nitric acid, finds use in industry through its property of making 
homogeneous compounds with nitrocellulose. Such a mixture yields 
a product resembling ebonite. Solutions of nitrated oils in acetone 
are used as varnishes, as a basis for paint, and for enameling leather. 
Castor oil finds a further use in the textile industry as a so-called 
‘wool oil’? (sulphonated castor oil), and very commonly is referred to 
as ‘‘castor-soap oil,” both of which are used for degreasing special 
woolen products. 
1 Hopkins, A. A.,ed. Scientific American Cyclopedia of Formulas . . .1077p.,illus. New York, 1911. 
