GB1102008A - Improvements in or relating to the manufacture of cellulosic films - Google Patents

Abstract

1,102,008. Cellulosic film. CELLOPHANE INVESTMENT CO. Ltd. 27 Sept., 1966 [30 Sept., 1965], No. 43140/66. Heading B5B. A cellulosic film contains uniformly dispersed therein solid organic polymeric particles of size 0À1-7À0Á, which modify the surface properties. Cellulosic film-forming composition, e.g. viscose or hydroxyethyl cellulose, containing the polymer, is extruded through a slit and treated with one or more liquids to form a coherent film. Polymeric materials listed are: amino-plastic, phenoplastic, polystyrene, polyvinyl, polyvinylidene, epoxy, polyacrylic, polymethacrylic, polyamide, alkyd, polyester, silicone, polyolefine, and polyfluoride resins; and exemplified are polyvinyl chloride, polychlorotrifluoroethylene and polyethylene; the polymers may be employed as pulverized particles or as latices, and mixed with the composition stream, or incorporated during the manufacture of viscose, e.g. during shredding of the alkali cellulose or during xanthation. The quantity of polymer should not be less than 0À05% by weight based on dry weight of cellulose content, and, if film is to be highly transparent, the quantity should not exceed 1À0%. Particles at or near the film surface layers protrude from the surfaces; the resultant film has improved antiblocking properties and has greater slip. A slip agent, e.g. an ester-, amide, or esteramide-wax, or a cationic surface active agent, may be applied to the film surface before the freshly formed film is dried; the slip agent may be incorporated in a bath containing glycerin.