JPH09254948A - Container used for microwave oven heating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly heat a center part of a container in a similar manner to a peripheral part by forming a bottom wall of the container to be a projected surface so as to be gradually higher from the peripheral part to the center part to facilitate transmission of the microwave in a microwave oven in the container having the bottom wall and the peripheral wall erected from a peripheral edge part. SOLUTION: A container 10 comprises a bottom wall 11, a peripheral wall 12 erected from a peripheral edge, and a flange 13 provided on an outer periphery of an upper edge, and the bottom wall 11 is formed spherical so as to be gradually higher on the whole from a peripheral part toward the center part. The spherical surface may be a true sphere, or an elliptical sphere, and the difference A in height between the center pat and the peripheral part is about 3-10mm. The container 10 is made of a synthetic resin with transmission property of the microwave and the heat, resistance such as polystyrene paper, and a crystalline polyester. The center part is heated more easily than other parts by reducing the thickness of the center part which is difficult for the microwave to transmit than the peripheral part, and the heating temperature is unified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin container suitable for housing foods and the like and heating them in a microwave oven.

[0002]

2. Description of the Related Art Containers of this type include a container having a flat bottom wall 1 as shown in FIG. 5 and a container having a step portion 1a formed on the bottom wall 1 as shown in FIG.

[0003]

SUMMARY OF THE INVENTION However, it is known that when a container such as the one described above is used for heating in a microwave oven, the contents are not heated uniformly, and the temperature of the central portion in particular does not rise.

Therefore, an object of the present invention is to provide a container in which the contents are heated uniformly in a microwave oven.

[0005]

In order to solve the above-mentioned problems, in the present invention, the bottom wall of the container has a convex surface which gradually increases from the peripheral portion toward the central portion.

As described above, by making the thickness of the central portion where microwaves are difficult to pass through smaller than that of the peripheral portion, that portion is more easily heated and the temperature is made uniform.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

As shown, the container 10 includes a bottom wall 11 and
The bottom wall 11 is composed of a peripheral wall 12 rising from the peripheral edge and a flange 13 provided on the outer periphery of the upper edge of the peripheral wall 12.
A spherical surface is formed so that the height gradually increases from the peripheral portion toward the central portion. This spherical surface may be either a true sphere or an ellipsoid. The height difference A between the central portion and the peripheral portion is preferably about 3 to 10 mm.

The bottom surface 11 is not limited to a spherical surface, but may be a linear inclined surface or a stepped convex surface having a mountain-shaped cross section.
The linear inclined surface is difficult to form, and in the case of a stepped shape, the release property of the food as the content is not good, so a spherical shape is preferable.

As a material of the container 10, for example, a synthetic resin having microwave transparency and heat resistance, such as polystyrene paper, crystallized polyester, a laminate of polypropylene and Eval, is used. It is also possible to partially form the microwave impermeable portion.

The corner portion 14 where the bottom wall 11 and the peripheral wall 12 are continuous is also preferably rounded as shown in the drawing.

The articles stored in the container 10 as described above are
Any food that can be cooked in the microwave, such as gratin or curry roux, can be used.

The planar shape of the container 10 is also arbitrary.
In addition to the elliptical shape shown, a circular shape, a polygonal shape, or the like can be adopted.

Next, examples and comparative examples will be described.

[0015]

Example: 25 m high made of polystyrene paper
An elliptical container having a volume of 200 m and a capacity of 200 cc was prepared. The bottom wall was formed so that the central portion was 5 mm higher than the peripheral portion, and a smooth spherical surface descending toward the peripheral portion was formed.

A commercially available frozen gratin is stored in this container,
After heating in a microwave oven of 500 W for 6 minutes, the temperature was measured by taking out and inserting a digital thermometer into the central part and the peripheral part. FIG. 4 shows the results.

[0017]

Comparative Example 1 The same container as in Example 1 was prepared. However, the bottom wall was made flat, and the same gratin was stored and heated in the same manner, and the temperature was measured.

[0018]

Comparative Example 2 A container similar to that of Example 1 was prepared. However, the bottom wall 12 was formed with a step portion having a height of 5 mm, which was separated from the peripheral edge portion by 7 mm.

The same gratin as in Example 1 was housed and heated in the same manner, and the temperature was measured.

[0020]

As described above, according to the present invention, since the bottom wall of the container is made to have a convex surface so that the central portion becomes high, the microwave of the microwave oven is easily transmitted in the central portion, and thus is easily heated, The heating can be performed uniformly as in the peripheral portion.

[Brief description of drawings]

FIG. 1 is a plan view of a container according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line I-I of the above.

FIG. 3 is a sectional view taken along the line II-II of FIG. 1;

FIG. 4 is a table showing temperature measurement results of Examples and Comparative Examples.

FIG. 5 is a sectional view showing a conventional container.

FIG. 6 is a sectional view showing another example of a conventional container.

[Explanation of symbols]

 A height difference 1 bottom wall 1a step 10 container 11 bottom wall 12 peripheral wall 13 flange 14 corner

Claims (1)

[Claims] 1. A microwave oven heating container having a bottom wall and a peripheral wall rising from a peripheral portion of the container, wherein the bottom wall is a convex surface that gradually increases from the peripheral portion toward the central portion. container.