moistureproof, they are yellow application examples packaging material, consisting of a cellulose hydrate film with a coating of vinylidene chloride - copolymer

摘要

805,072. Moistureproof sheet wrapping materials. BRITISH CELLOPHANE, Ltd. Aug. 2, 1957 [Aug. 8, 1956], No. 24332/56. Addition to 663,645 and 727,414. Class 140. A vinylidene chloride copolymer comprising (a) 91 to 94 parts by weight of monomeric vinylidene chloride, (b) 3 to 7 parts by weight of monomeric methyl methacrylate, and (c) 1 to 3 parts by weight of monomeric vinyl acetate (the total being 100 parts by weight) is coated on to a base film of water-sensitive organic non-fibrous material. Not more than 2 parts by weight of itaconic acid may be included as an anchoring agent. Between 0.1 and 3 per cent of an ester type wax such as carnauba, spermaceti, candelilla and palm wax, hydrogenated castor oil, benzyl stearate, pentaerythritol distearate, pentaerythritol tetrastearate and n-octadecyl stearate, may be included as a slip-agent. The coating may be applied from solution in an organic solvent such as tetrahydrofuran, or preferably as a colloidal aqueous dispersion. In an example an aqueous dispersion of vinylidene chloride, methyl methacrylate and vinyl acetate containing itaconic acid, ammonium octadecyl sulphate, a formaldehyde-naphthalene sulphonic acid condensate, ammonium persulphate and sodium metabisulphite is prepared. An emulsion of carnauba wax is added and the resulting dispersion coated on to both sides of a regenerated cellulose film. Specifications 655,006, 655,732, 749,276 and 756,851 also are referred to.