watermelons of cellulosehydratfolien with vinylidene chloride mischpolymerisaten using a verankerungsmittels

摘要

766,827. Moistureproof regenerated cellulose film. BRITISH CELLOPHANE, Ltd. May 20, 1955 [May 26, 1954], No. 15601/54. Class 140. Regenerated cellulose film is treated with a polyalkylene imine before the application of a moistureproof coating comprising a vinylidene chloride copolymer. Preferred is polyethylene imine of viscosity 100 poises in 20 per cent aqueous solution at 20‹ C. The imine may be added to the viscose or cuprammonium cellulose from which the film is formed, or the film in the " gel state," before drying, may be passed through an aqueous bath containing say 0.01- 1 per cent imine at pH 4-11 and 15-80 ‹ C. In the latter case the film may be treated in a preceding bath with a softening agent, or a softening agent, e.g. glycerine or polyethylene glycol may be added to the aqueous bath. Alternatively, a thin coating of the imine may be applied to the finished dried film in solution, 0.01-1 per cent, in an organic solvent, e.g. ethyl alcohol, and the solvent evaporated by heat. The vinylidene chloride copolymer with e.g. acrylonitrile, methyl methacrylate, methyl acrylate, ethyl acrylate, with or without itaconic acid or anhydride, may be applied in aqueous dispersion or organic solvent solution to provide coatings 0.00005 inch thick on each side of the film. Specifications 622,481 and 655,732 are referred to.