| 摘要 |
514,715. Cellulose nitrate film. KODAK, Ltd. May 14, 1938, No. 14429. Convention date, May 18, 1937. [Class 2 (ii)] Sheeting adapted for use as photographic film base is made by depositing in the form of a film on a film-forming surface a solution having a composition falling within the area under curve A in Fig. 1 of the drawings and consisting of cellulose nitrate dissolved in a mixture of methyl alcohol and one or more co-solvents, coagulating the solution in presence of steam, removing the film from the filmforming surface while still containing a large amount of solvent and then curing out the residual solvent. Co-solvents mentioned are acetone, methyl ethyl ketone, diethyl ketone, ethylacetate, butylacetate, ethylether, methyl ethyl ether, isopropyl ether, dioxane, ethyl " Cellosolve " (Registered Trade Mark), methyl " Cellosolve," dimethyl " Cellosolve," and methyl " Cellosolve" acetate. The filmforming composition may also contain butyl alcohol and plasticizers such as triphenyl phosphate and camphor. In Fig. 2, the filmforming solution is led from a hopper 9 on to the rotating casting wheel 2. Air entering through filter 12 is charged with steam by means of jet 13, and after passing through heater 14, is led through the wheel casing 6. The coagulated film leaves the wheel at the stripping roll 15 and passes to a curing chamber.
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