Abstract: An expandable film includes a core layer and first and second non-expandable outer layers. The core layer includes expandable microspheres dispersed in a matrix having at least 40% of one or more matrix polymers selected from (i) ethylene/unsaturated ester copolymer having an unsaturated ester comonomer content of from 20% to 60%, (ii) ethylene/alpha-olefin copolymer having a density of less than 0.915 g/cc, and (iii) combinations thereof. The melting point of the one or more matrix polymers is at least 15° C. below the activation temperature of the expandable microspheres. The first and second non-expandable outer layers each independently include one or more thermoplastic polymers having a melting point at least 15° C. below the activation temperature of the expandable microspheres.

Abstract: A product is packaged in a pressure-reclosable package comprising a multilayer film having a heat-sealable, pressure-reclosable inside layer. The inside layer contains a hyperbranched polyolefin having at least 70 side chain branches per 1000 carbon atoms and a density of up to about 0.885 g/cc, and/or an ethylene/alpha-olefin elastomer having a density of up to about 0.885 g/cc. The package is opened and a portion of the product removed, and a pressure-induced seal is used to re-close the package at a temperature of at least 11° C. The reclosed package is then placed in an environment having a temperature of from about ?50° C to +1° C., so that a cooled pressure-reclosed seal at least doubles in strength.