| 摘要 |
508,822. Films ; coated sheets. BRITISH CELLOPHANE, Ltd. Aug. 22, 1938, No. 24705. Convention date, Aug. 23, 1937. [Class 2 (ii)] [Also in Group VIII] A regenerated cellulose film or sheet is coated with a solution of a product formed by the mixed polymerization of a compound containing an olefinic double bond with an ethylenealpha #-dicarboxylic acid or with an anhydride, substitution or other derivative of such acid, and then with a solution of a hydrophobic composition. The intermediate layer acts as an anchoring layer between the regenerated cellulose and the hydrophobic composition. The cellulosic layer may contain glycerol, glycol, or other softener. An acid chloride, alkyl or aryl acid ester, or anhydride, of maleic, fumaric, or other ethylenealpha#-dicarboxylic acid or the free acid may be. used as one component of the mixed polymer provided it is polymerizable. Maleic acid itself is not used. The polymers may be subjected to a heat treatment subsequently to their production. Ester polymers may be subjected to saponification prior to the heat treatment. The coated and finished lacquered films may be subjected to a heat treatment. The second component of themixed polymer may be a vinyl ether e.g. vinyl methyl ether. Equal quantities of the two components may be used in making the mixed polymers. The hydrophobic layer may be formed from a nitrocellulose lacquer containing wax and resin, or it may be a waterresistant glue, or a permanent adhesive material containing rubber. In an example, a cellulose hydrate film is coated with a solution of a condensation product of maleic anhydride and vinyl methyl ether dissolved in methyl acetate and cyclohexanone. The excess solution is removed and the film is dried. The film is then coated with a cellulose nitrate lacquer containing dibutyl phthalate, paraffin wax, dewaxed dammar resin, ethyl acetate, toluene, and ethyl alcohol. The coated film is dried. In another example, a cellulose hydrate film is coated with a solution of a condensation product of maleic anhydride and vinyl octadecyl ether in benzene, butyl acetate, and cyclo-hexanone. The excess solution is removed and the film is dried. One side of the film is then coated with a permanent adhesive having a basis of rubber. The film is cut into strips and wound into rolls. The coatings remain firmly attached to the film even when it is swollen by immersion in water. Specifications 376,479 and 376,481 are referred to. |
