Package for cooking by microwave oven
Provided is a package for cooking in a microwave oven, in which a synthetic resin container body having a flange part is filled with contents and a lid is heat-sealed to the flange part to seal the package hermetically. Independent concave parts sandwiching a heat-sealed part are provided in a part of the flange part on the inner and outer sides of the heat-sealed part to form, on the heat-sealed part, a projection part directed to the inner direction of the container and serving as a steam releasing part by automatically opening. The package is prevented from being broken or deformed by preventing the heat-sealed part from being peeled immediately after the contents are placed in the container body. When heating cooking is performed in a microwave oven, the package improves the taste of the contents by the steaming effect. The lid is sure to automatically open by the increase of the pressure in the container.
1. A package for cooking in a microwave oven, in which a container body made of a synthetic resin and having a flange part is filled with contents, and a lid is heat-sealed to the flange part to seal the package hermetically via a heat-sealed part, wherein individual concave parts are provided only in a portion of the flange part to be opened automatically when the package is heated in a microwave oven, and wherein the respective individual concave parts are located on an inner side and an outer side of the heat-sealed part, opposite one another, thereby forming a projection part directed in an inward direction of a container at the heat-sealed part, and wherein the lid is heat-sealed to a flat surface of the flange other than the projection part.
2. A package for cooking in a microwave oven according to claim 1 , wherein an opening part projecting in an outward direction of the container is formed at a position opposed to the projection part of the heat-sealed part of the package for cooking in a microwave oven.
3. A package for cooking in a microwave oven according to claim 2 , wherein the container body made of a synthetic resin is a square container, and the projection part and an opening part are formed respectively in corner portions opposed to each other in the container.
4. A package for cooking in a microwave oven according to claim 2 , wherein the opening part is formed in a V-shape.
5. A package for cooking in a microwave oven according to claim 1 , wherein the projection part is formed in a U-shape or a V-shape.
6. A package for cooking in a microwave oven according to claim 1 , wherein a seal strength at the projection part formed at the heat-sealed part is 5 to 30 N/15 mm.
7. A package for cooking in a microwave oven according to claim 1 , wherein depths of the concave parts at both sides of the projection part are 0.05 to 3 mm.
8. A package for cooking in a microwave oven according to claim 1 , wherein a width of the heat-sealed part at the projection part is 0.5 to 5 mm.
9. A package for cooking in a microwave oven according to claim 1 , wherein the concave parts define the outline of the projection part.