METALLISED POLYPROPYLENE FILM WITH WELL-PRESERVED BARRIER PROPERTIES Russian patent published in 2011 - IPC B32B27/32 B32B15/08 B32B15/85 C08J5/18 B65D65/40 

FIELD: process engineering.

SUBSTANCE: invention relates to multilayer metallised biaxially-oriented polypropylene films used for food packing and to method of their production. Said film comprises main layer A made from crystalline home- or copolymers of propylene comprising bonds C₂-C₁₀ of alpha-olefine, one top layer B made from propylene copolymer containing 3 to 6 wt % of the bonds of linear C₄-C₁₀-1-alkene, and metal layer M applied on the surface of top layer B. Propylene copolymer of layer B has fraction soluble in xylene at 23°C, less than 4.0 wt %, Vick softening point above 135°C indenter depth in Vick test smaller than or equal to 0.05 mm at 120°C. Method of film production comprises co-extrusion of layers A and B, biaxial orienting of co-extruded layer A and B, treatment of top layer B surface and metal deposition on said layer.

EFFECT: multilayer metallised biaxially-oriented polypropylene films with high oxygen and steam barrier properties.