Reclosable Microwave-Suitable Packaging

Abstract

The invention relates to a packaging suited for heating in microwave ovens, ovens or double boilers, which is comprised of a multilayer film material having at least one area that is rendered permeable when an internal pressure generated by the microwave heating is exceeded. The invention is characterized in that this area is formed by a microperforation that is covered by a label or by a hot stamping film or by a varnish coating.

1 ) Packaging suitable for heating in the microwave, oven, or water bath consisting of a multi-layered film material having at least one area which becomes permeable when the internal pressure produced by the microwave heating is exceeded characterized by this area being produced by a microperforation covered by a label, hot stamping film, or a varnish coating. 
     
     
         2 ) Packaging in accordance with  claim 1  characterized by the microperforated area having, for example, the shape of a circle, rectangle, square, trapezoid, triangle, an ellipsis or semi-ellipsis, but also the shape of specific marks, symbols, letters, text, and the like. 
     
     
         3 ) Packaging in accordance with one of  claims 1  or  2  characterized by the microperforation being shaped like a circle, a slit, a rectangle, a square, and the like. 
     
     
         4 ) Packaging in accordance with one of  claims 1  to  2  characterized by the microperforation being shaped like a logo. 
     
     
         5 ) Packaging in accordance with one of  claims 1  or  2  characterized by the microperforated area having a varnish coating based on a mixture or a polyester acrylate, or epoxyacrylate colophonium, acrylate, alkyde, melamine, PVA, PVC, isocynate, urethane systems, butadiene, a styrene system, or their copolymers. 
     
     
         6 ) Packaging in accordance with  claim 3  characterized by the varnish coating, the label, or the hot stamping film containing an energy-absorbing additive. 
     
     
         7 ) Packaging in accordance with one of  claims 1  to  4  characterized by intermediate layers being provided between the external and internal layers. 
     
     
         8 ) Packaging in accordance with  claim 5  characterized by the intermediate layers being barrier layers, absorber layers, browning layers, [layers which provide] flexibility, or strength, or rigidity, and/or printed layers. 
     
     
         9 ) Packaging in accordance with one of  claims 1  to  6  characterized by the side of the interior layer facing the interior space of the packaging having an absorber layer which is fixed in place by a membrane with a rupture site. 
     
     
         10 ) Packaging in accordance with one of  claims 1  to  7  characterized by different markings being applied to the area of the microperforation which show a definite change in the optical image after the valve is opened. 
     
     
         11 ) Film material for the manufacture of packagings in accordance with one of  claims 1  to  8 .