GB334271A - Improvements in the manufacture of films - Google Patents

Abstract

334,271. M³nch, C. April 4, 1929. Cigarettes.-A non-transparent composite film of cellulose ester, especially cellulose acetate, for use in tipping cigarettes comprises a very thin layer in which the colour or pigment if present is in insufficient quantity to destroy its waterproof character, and a very thin layer containing sufficient finely divided pigment to render it substantially non-waterproof and give it a matt surface. The film as a whole is waterproof and non- porous, but, owing to the matt surface and porosity of the non-waterproof layer, it may easily be united to the paper of a cigarette by means of an aqueous adhesive. The film may be made by casting one of the layers as a solution upon a surface from which it can afterwards be stripped, allowing it to dry, casting the other layer thereon, allowing this to dry, and finally stripping the united layers as a single film. The pigment in the waterproof layer may consist of dyestuffs, mineral pigments, or metal powder, and the finely divided filler in the non-waterproof layer may be barytes with colouring matter if desired. In an example, the waterproof layer contains 2 parts by weight of bronze powder to each part of acetyl cellulose, i.e. about 1 volume of bronze powder to 3 volumes of acetyl cellulose, and the non- waterproof layer contains about 1 volume of mineral pigment to 1 volume of acetyl cellulose. Reference has been directed by the Comptroller to Specification 337,501.