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JP-2026075766-A - food packaging containers

JP2026075766AJP 2026075766 AJP2026075766 AJP 2026075766AJP-2026075766-A

Abstract

[Problem] To provide a microwave-safe food packaging container that can suppress the generation of resin powder by suppressing the generation of fluff. [Solution] A steam vent hole 30 is provided on the top surface of the lid, and a thickened portion 32 is provided on the opening edge of the steam vent hole 30. The cross-sectional shape of the thickened portion 32 is such that, when the length along the upper extension line 51 between the upper bulge starting point 50 and the upper intersection point 52 is LU, the length along the lower extension line 54 between the lower bulge starting point 53 and the lower intersection point 55 is LL, and the thickness of the sheet is T, then T ≤ LU and T ≤ LL. [Selection Diagram] Figure 5

Inventors

  • 内田 純巨

Assignees

  • 株式会社エフピコ

Dates

Publication Date
20260511
Application Date
20241023

Claims (4)

  1. A microwave-safe food packaging container comprising a container body and a lid thermoformed from a sheet of olefin resin that is attached to the container body, The top surface of the lid has a steam vent to release steam from inside the container to the outside during microwave heating. The opening edge of the steam vent is provided with thickened sections that bulge outwards on the upper and lower sides, extending around the entire circumference. In a cross-sectional view when the sheet is cut vertically across the steam vent, The outer edge of the thickened portion has an upward curved portion that curves upward and bulges out from the upper surface of the sheet, a downward curved portion that curves downward and bulges out from the lower surface of the sheet, and an inward curved portion that connects the upward curved portion and the downward curved portion and curves upward and bulges out towards the center of the steam vent hole. In the aforementioned cross-sectional view, Let LU be the length along the upper extension line between the upper bulge initiation point where the upward curved portion begins to bulge from the upper surface of the sheet, and the upper intersection point where the upper extension line, extended from the upper surface of the sheet toward the center of the steam vent hole, intersects with the outer shape of the thickened portion. Let LL be the length along the downward extension line between the downward curvature starting point where the downward curved portion begins to bulge from the underside of the sheet, and the downward intersection point where the downward extension line, extended from the underside of the sheet toward the center of the steam vent hole, intersects with the outer edge of the thickened portion. When the thickness of the sheet is T, A food packaging container where T ≤ LU and T ≤ LL.
  2. In the aforementioned cross-sectional view, Let A be the length of the line connecting the midpoint of the line connecting the upper bulge initiation point and the lower bulge initiation point, and the innermost point in the inwardly curved section that is closest to the center of the steam vent hole. When B is the distance in the thickness direction of the sheet between the highest point of the upper curved section and the lowest point of the lower curved section, A food packaging container according to claim 1, wherein 0.8 ≤ B/A ≤ 1.1.
  3. In the aforementioned cross-sectional view, A food packaging container according to claim 2, wherein 1.8 ≤ B/T ≤ 2.2.
  4. The shape of the steam vent in a plan view is an elongated hole shape with a width of 0.15 to 1 mm and a length of 2 to 30 mm along the steam vent, as described in any one of claims 1 to 3.

Description

This invention relates to a food packaging container for microwave heating, which has steam vents on the top surface of the lid. For example, prepared foods in supermarkets are placed in packaging containers. When these containers are microwaved, the steam generated from the food needs to be vented. One method of venting steam is to provide exhaust holes in the top surface of the container lid. Patent Document 1, shown below, describes a lid with multiple micro-holes 100 formed on its top surface by laser processing, as shown in Figure 11. Annular bulges 101 are provided around the periphery of these micro-holes 100. Furthermore, the cross-section of the micro-holes 100 is described as expanding from bottom to top. However, because the lid is molded from a biaxially oriented sheet of styrene resin, it is hard and brittle. Therefore, there is a risk of fuzzing occurring on the walls of the micropores 100 during the perforation process. If fuzzing occurs on the walls of the micropores 100, the fuzz may be removed and resin powder generated during packaging or transportation due to friction against the top surface of the lid, requiring the removal of this resin powder. Patent No. 6816224 A perspective view showing the open state of a food packaging container according to one embodiment of the present invention.Enlarged plan view of the lid of the food packaging container.Enlarged plan view of the main part of the steam vent hole in the same lid.Figure 3 shows a cross-sectional view along the line P-P.Enlarged view of section Q in Figure 4.An enlarged cross-sectional view of the main part of the steam vent hole in the lid of a food packaging container in another embodiment of the present invention.A photograph serving as a substitute for a diagram, showing a magnified cross-section of the steam vent.A photograph serving as a substitute for a diagram, showing a magnified cross-section of the steam vent.A partially enlarged plan view of the lid of a food packaging container in another embodiment of the present invention.Enlarged plan view of the main part of the steam vent hole in the same lid.Cross-sectional view of a conventional steam vent. The following description of a food packaging container according to one embodiment of the present invention will be made with reference to Figures 1 to 5. The container in this embodiment is for storing various foods and is microwave-safe, allowing it to be heated in a microwave oven while closed without being opened. The container comprises a container body 1 and a lid 2. Both the container body 1 and the lid 2 are formed from a synthetic resin sheet by various thermoforming (sheet molding) methods such as vacuum forming or pressure forming. The shape of the container in plan view is arbitrary and may be round, oval, roughly square, roughly polygonal, etc. In this embodiment, the shape of the container in plan view is circular. <Container body 1> The container body 1 has a circular opening that opens upwards. The lid 2 fits onto the container body 1 to close the opening of the container body 1. The fitting between the container body 1 and the lid 2 is preferably an internal fitting structure in which the fitting portion 23 of the lid 2 is brought into contact with the inside of the fitting portion 13 of the opening of the container body 1. By using an internal fitting structure, the sealing performance can be improved so that the soup or other contents contained inside does not leak when the lid is closed. If necessary, a tray (not shown) may be placed between the container body 1 and the lid 2. The container body 1 can hold various foods such as jelly-like soups, noodles, and dried ingredients, allowing them to be heated directly in a microwave oven and consumed. The container body 1 can be obtained by thermoforming a sheet made of heat-resistant resin material. For use in a microwave oven, it is particularly preferable to use a foamed heat-resistant resin material for the container body 1. This prevents the container from becoming hot to the touch when removed from the microwave after heating, reducing the risk of burns, and efficiently transmits the microwave's electromagnetic waves to the food, allowing for uniform and rapid heating. The container body 1 comprises a bottom portion 10, a side portion 11 extending upward from the outer edge of the bottom portion 10 while expanding upward, and a flange portion 12 extending outward from the upper end of the side portion 11. The bottom portion 10 may be provided with legs of various shapes (not shown). The bottom portion 10 may also be provided with a raised bottom portion (not shown). Preferably, a body fitting portion 13 is formed on the upper part of the side portion 11, into which the lid fitting portion 23 of the lid 2 (described later) fits inside. The shape of the body fitting portion 13 may vary, but one example is an inverse tapered shape that gradually decreases in diameter towards the top. When the body fitting