Sealable, opaque, biaxially oriented, multilayer polypropylene@ film

摘要

Sealable, opaque, biaxially-oriented, multilayer polypropylene (PP) film (I) is claimed, with a core layer (A), interlayer(s) (B) on one or both sides and outer layer(s) (C) on one or both sides; (a) layer (A) contains a PP polymer or PP mixt., CaCO3 with particle dia. 1-2 microns and opt. other additives, (b) (B) can be the same or different, (c) (B) contain PP polymer or PP mixt. and opt. additives, (d) (C) can be the same or different, (e) at least one layer (C) is not above 0.4 micron thick and (f) (C) is a copolymer of ethylene (E) and propylene (P), (E) and butylene (BU), (P) and (BU), or (E) or (P) and a 5-10C alpha-olefin (OL), or a terpolymer of E/P/BU or E/P/OL, or a mixt. of PP with one or more of the above co- and/or ter-polymers, or a mixt. of 2 or more of the above co- and/or ter-polymers, opt. contg. additives. Also claimed is a process for the prodn. of (I), by co-extrusion of the corresp. polymer melts through a sheet die, solidification by cooling, biaxial stretching and heat fixing, opt. followed by corona or polarised flame treatment of surface(s); at least one outer layer is sealable and is not above 0.4 micron thick.