Film is used as a bladder that expands in response to an increase in the internal pressure while contents are heated, such as micro-waved. A laser-scored vent(s) is provided with scoring of an reduced extensibility layer, such that expansion of the package due to internal pressure (steam) pulls the film across the width of the package causing it to stretch to the point that the vent point(s) breaks through or ruptures the sealant film allowing the pressure/steam to escape.
↧