An improved process for removing layers from used films or film waste by means of alkali lye without special mechanical treatment

摘要

Gelatine, albumen, and other coating layers are removed from used films or film waste by treating the films for a few minutes with a solution containing 8 per cent or more of caustic alkali at a temperature of about 60 DEG C. The time of treatment is shorter the higher the alkali concentration, and it may be 1--3 minutes for an alkali concentration of 15 per cent. Gelatine layers even when hardened or provided with a varnish coating are so completely dissolved away by the alkali treatment that a separate removal by brushes, scrapers, knives, or other mechanical device is not necessary. Albumen and other foundation layers are also dissolved away by the treatment. The celluloid film material thus recovered is free from cloudiness. The process may be applied to waste kinematograph and other photographic films, and to films containing no image layer. Specifications 331,006, [Class 2 (iii)], and 364,845, [Group XV], are referred to.