Improvements in or relating to the manufacture of moisture-proof, heat-sealable sheet wrapping materials

Abstract

Abstract A film-forming composition comprises an interpolymer of vinylidene chloride/acrylonitrile/acidic ethylenic compound prepared from a mixture of more than 80 per cent vinylidene chloride, between 0.1 and 2.5 per cent of acidic compound and the remainder acrylonitrile, and a solid polymer or interpolymer of ethylene incorporated in an amount up to 3 per cent of the weight of solids as a slip agent. The acidic ethylenic compound may be citraconic acid or anhydride, itaconic acid or anhydride, a mixture of citraconic and itaconic anhydrides obtained by distillation of citric acid, mesaconic acid or acrylic acid. The ratio of vinylidene chloride to acrylonitrile may be as high as 96 : 4, the preferred being 90 : 10. The interpolymers may be prepared as described in Specification 674,728. The composition may be applied in solution to a base film (see Group VIII), or may be converted into self-supporting films by casting &c. to produce a moisture-proof, heat-sealable sheet wrapping material. Suitable solvents are methyl ethyl ketone or a mixture of equal parts of toluene and methyl ethyl ketone. Specified ethylene interpolymers are those with 1,3-dioxolane; carbon monoxide; vinyl acetate, formate, chloride and cyanide; vinylidene chloride; acrylic, methacrylic and itaconic acids and their esters; tetrafluoroethylene; and styrene. Specification 600,164 also is referred to.

Inventors

• 👤 William Berry
• 👤 Charles Robert Oswin
• 👤 John Kay

Bibliographic Details