The dry casting of viscose film

✍ Scribed by C. R. Price; V. C. Haskell

• Publisher: John Wiley and Sons
• Year: 1961
• Tongue: English
• Weight: 451 KB
• Volume: 5
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1961.070051804

✦ Synopsis

Abstract

Regenerated cellulose film prepared by a dry‐cast method has demonstrated outstanding superiority over similar film produced by the conventional wet‐cast process. Factors contributing to the superior quality of film prepared by the dry cast process are: (1) physical properties several times greater than for wet‐cast film of corresponding thickness; (2) high durability at conditions of low temperature and low humidity even without the addition of softening agents, and (3) outstanding dimensional stability when exposed to conditions of varying temperature and humidity. The dry‐cast cellophane differs structurally from the commercial product in having a lower degree of order, a lower degree of swelling in the gel form, and minor differences in molecular orientation. A commercial process for producing dry cast cellophane may be envisioned as a heated, polished support for drying the viscose film; a regenerating system of alcoholic hydrochloric acid, hot glycerine, or a hot, oxygenfree gas; a water both for purifying the film; and a conventional cellophane dryer. The ideal viscose composition for producing dry‐cast cellophane is high cellulose content, moderately high DP, sufficient degree of substitution on the cellulose to yield a high degree of dispersion, and low caustic content.