| 摘要 |
557,356. Films. LORD, W. E. April 8, 1942, No. 4585. [Class 2 (ii)] [Also in Group XXXVI] A film for use in a dry cell is made from a high-viscosity ester-soluble nitro-cotton, using a plasticizer such as castor oil or tricresyl phosphate. The film may be made by applying the film-forming solution to a moving band of porous paper coated with a water-soluble gum. After the solvent has evaporated, the resulting film can be removed by wetting the paper to dissolve the gum, thereby permitting the film to be stripped from the band. The solution from which the film is made may comprise nitro-cellulose, ethyl acetate, butyl acetate, toluol, butyl alcohol, acetone and tricresyl phosphate, proportions being given in the Specification. |
