MELT-EXTRUDABLE POLYVINYL ALCOHOL COMPOSITIONS AND COLD WATER-SOLUBLE FILMS

摘要

Compositions consisting essentially of a (i) resin mixture containing a low molecular weight polyvinyl alcohol and a medium molecular weight polyvinyl alcohol, and optionally, a copolymer of vinyl alcohol and an ethylenically unsaturated ester and (ii) as a plasticizer a polyethylene glycol, which compositions can be used for preparing films by melt extrusion or aqueous casting. These films are suitable for use as packaging film in automatic packaging equipment. They can be used to package pulverulent materials, and the film package containing the pulverulent material can be charged directly to water in which the film will dissolve, thus eliminating the problem of user contact and exact measuring of the package contents, as well as disposal of containers in which the pulverulent materials would otherwise be packaged. Moreover, these films provide enhanced resistance to breakage of packages made therefrom when such packages are handled or shipped, even under cold or dry conditions.