Hermetically heat-sealable, pressure-reclosable packaging article containing substantially spherical homogeneous polyolefin

Abstract

A multilayer film has a hermetically heat-sealable, pressure-reclosable, outer heat seal layer which contains a blend of a substantially spherical homogeneous polyolefin (i.e., SSH polyolefin) with a different thermoplastic polymer. The SSH polyolefin is present in an amount of from about 20 to 80 weight percent, and the different thermoplastic polymer is present in the layer in an amount of from about 80 to 20 weight percent, based on total layer weight. The SSH polyolefin has at least 60 side chain branches per 1000 carbon atoms, and has a melt index of from about 1 to 10. The invention also includes a process for making the multilayer film. Also disclosed is a roll of film comprising a disposable outer layer which is directly and peelably adhered to a first surface of second layer comprising the SSH polyolefin, a packaging article comprising an inside layer comprising the SSH polyolefin. The invention also includes a process for making a sealed article in which the multilayer film is heat sealed to itself or another article by heating the seal layer to a temperature of at least 50° C. Finally, the invention includes a hermetically heat sealable, pressure reclosable multilayer film comprising a sealant layer comprising, at least 30% by weight of a single site catalyzed SSH polyolefin having a density of from about 0.85 to 0.89 g/cc, a melt index of 0.5 to 8 g/10 min, a Mw/Mn less than 3, and a short chain branching level of about 60 to 100 methyl groups per 1,000 carbon atoms, and an outer heat resistant layer comprising a thermoplastic polyolefin having DSC melting point or glass transition of at least about 100° C., the outer layer having a coefficient of friction of less than 0.5 as measured by ASTM D 1894.