GB447371A - Improvements relating to cellulose derivative moisture-proofing compositions - Google Patents

Abstract

A moisture-proofing composition particularly for cellulose, cellulose derivative, gelatine &c. films or foils, consists of a solution in an organic solvent of nitrocellulose or other cellulose derivative, a plasticizer, chlorinated rubber and a wax, the amount of the wax exceeding 10 per cent of the solid constituents of the composition. Amounts of wax of 14 per cent may be employed while still obtaining a transparent and glossy coating, and this amount may be considerably increased if a gum or resin is included in the composition, regard being then had to any wax brought in by the gum or resin. The added wax may be paraffin or like hydrocarbon wax. Suitable proportions of the constituents are: chlorinated rubber, 10--40 per cent of the wax; gum or resin, 80--250 per cent of the combined weight of wax and chlorinated rubber. In preparing the composition, the nitrocellulose and the chlorinated rubber and wax are first dissolved separately, the wax being dissolved simultaneously with or subsequent to the chlorinated rubber; the gum or resin is usually dissolved and incorporated with the nitrocellulose or in the solvent for the chlorinated rubber either before or simultaneously with the wax; the solutions are finally mixed. In examples, the following solutions are mixed together: nitrocellulose, dimethyl phthalate, diethyl phthalate, triphenyl phosphate, dammar resin, ethyl acetate and toluene, and a chlorinated rubber and wax in solution in toluene; nitrocellulose, triphenyl phosphate, dimethyl phthalate and ethyl acetate, and dammar resin, chlorinated rubber, wax in solution in toluene. Specifications 283,109, [Class 140], and 437,140 are referred to.