108 CASEIN. 



To obtain a homogeneous compound of nitrocellulose and 

 casein, the latter is formed into a plastic mass with one of 

 its solvents, e.g., an aqueous solution of borax ; the excess of 

 water is removed, the mass is dipped in alcohol, to extract a 

 portion of the water absorbed by the casein, the excess of 

 liquid is removed from the mass, and the latter is then 

 kneaded along with plastic nitrocellulose until homogeneous. 



When camphor is used, 100 parts of nitrocellulose are 

 treated with 40 to 50 parts of camphor dissolved in 50 to 60 

 parts of 95 to 96 per cent, alcohol. The casein is rendered 

 plastic in the following manner? The casein is immersed for 

 twenty-four to forty hours in a 5 per cent, aqueous solution 

 of borax, or other casein solvent, e.g., sodium carbonate. It 

 is next dried, dipped in alcohol, acetone, sulphuric ether or 

 acetic acid, dried for several hours or pressed, and mixed 

 with the nitrocellulose. Another method is to dip the casein 

 for twenty-four to forty-eight hours in borax solution, or in 

 some other casein solvent containing 3 to 4 parts of alcohol 

 or other solvent of nitrocellulose. The casein and nitro- 

 cellulose products are afterwards rolled together for three 

 to four hours between rollers, and thus furnish a transparent 

 or translucent and perfectly homogeneous mass, which can 

 be drawn out into sheets 2 to 4 inches thick. These sheets 

 are pressed together, as in making celluloid, the block being 

 thereupon cut into plates of the desired thickness. Mineral 

 and other substances can be easily added to the mass. 

 According to an additional patent (23rd Feb., 1902) caseates 

 are added to nitrocellulose that has been treated with alco- 

 holic camphor, the mixture being then treated in the same 

 way as celluloid. 



According to the master patent (German patent 138.783), 

 a mass resembling celluloid is obtained by adding casein to 

 ordinary celluloid ; and pure casein may be replaced, for this 

 purpose, by a compound of casein with a metallic oxide. For 



