Abstract: An apparatus and method for producing microperforated patches for MAP includes drilling or punching microperforations through continuously advancing label stock. Holes can be drilled by at least one microperforating laser traversed across the label stock as it advances, a laser beam deflected or split using a servo-driven galvanometer, beam splitters, or a plurality of mirrors, or by drills mounted into a rotating die cylinder across which the stock passes as it is advanced. Numbers and sizes of microperforations can be adjusted by manipulation of laser control parameters, or by exchange of die cylinders. The laser can be a CO2 laser with between 10 W and 100 W output. The drills can be carbide drills. The label stock is typically 6-18 inches wide, and can include an adhesive covered by a release sheet. The stock to be microperforated can include separate rows of labels or can be suitable for die-cutting after microperforation.

Abstract: A package suitable for storing and cooking foods without user manipulation includes a venting mechanism actuated primarily or exclusively by temperature, rather than pressure. A vent hole can be sealed by a patch attached by a thermoplastic adhesive having a selected, well characterized Tg, or the patch itself can be a thermoplastic polymer having a selected Tg. The patch can be convection-heated, or a microwave absorbing susceptor material can be applied to the adhesive or patch for direct microwave heating. The patch can include a region that is melted by convection or by a susceptor material. A porous patch can be sealed by a low melting temperature polymer or by thermally sensitive ink. And/or, microwave susceptor material can be applied directly to a package wall and can melt a ventilation hole through the wall when a specified amount of microwave energy has been applied.

Abstract: An apparatus and method for producing microperforated patches for MAP includes drilling or punching microperforations through continuously advancing label stock. Holes can be drilled by at least one microperforating laser traversed across the label stock as it advances, a laser beam deflected or split using a servo-driven galvanometer, beam splitters, or a plurality of mirrors, or by drills mounted into a rotating die cylinder across which the stock passes as it is advanced. Numbers and sizes of microperforations can be adjusted by manipulation of laser control parameters, or by exchange of die cylinders. The laser can be a CO2 laser with between 10 W and 100 W output. The drills can be carbide drills. The label stock is typically 6-18 inches wide, and can include an adhesive covered by a release sheet. The stock to be microperforated can include separate rows of labels or can be suitable for die-cutting after microperforation.