Moisture-impermeable package

Claim 1

A moisture-Impermeable package comprising: A. a container having a bottom wall, upstanding side walls cooperating with said bottom wall for defining a compartment to retain product, and an upper wall defining an opening in communication with said compartment; B. a lid member movable between a closed position overlying said opening, and an open position exposing said opening; C. channel means integral with said container and circumscribing said opening, said channel means having an open upper end defined by spaced upstanding ledge members; D. a substantially air-impervious, thin, flexible plastic web disposed in a substantially flat condition over the open upper end of the channel means and the opening into the container compartment, said plastic web being adhered to the upstanding ledge members to provide a flexible, substantially airimpervious closure for both said channel and container compartment; E. separation means associated with the plastic web for permitting the formation of an opening through the plastic web in a region overlying the opening into the container compartment without disrupting the air-impervious closure of the channel means; and F. rib means projecting from the lid member in cooperative relationship with the plastic web and the lid member is in its closed position for engaging and flexing the plastic web intermediate the upstanding ledge members of said channel means to thereby provide a substantially moisture-impervious seal about the opening into the container compartment after the opening through the plastic web has been formed.