Packaging container and lid therefor
A packaging container according to the present invention is molded of a thin synthetic resin sheet. The outer peripheral edge of an opening of the packaging container 1, 18 has an outwardly extended flange 11. The outer peripheral edge 11a of the flange 11 is corrugated in the vertical or horizontal direction. By corrugating the outer peripheral edge 11a of the flange 11, the corrugated outer peripheral edge 11a can give a soft touch to user's hand or finger or a wrapping film contacting the same. As a result, user's hand or finger can be prevented from being hurt and the wrapping film can be prevented from being broken.
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This is a Continuation of U.S. application Ser. No. 10/523,005, filed Aug. 9, 2005, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a packaging container and a method of producing the same, and especially to an opening peripheral edge encompassing an opening of a packaging container.
2. Description of Related Art
Among synthetic resin packaging containers, containers having an inside storage part formed by sheet molding recently have come to need space saving property. Therefore, needs have changed from containers molded of a foamed sheet to containers molded of thin synthetic resin sheet. A synthetic resin sheet is molded into a container shape and then the peripheral edge of the container shape is cut, whereby a container molded of thin synthetic resin sheet can be obtained. Generally, such a packaging container has a shape provided with a wide opening. A packaging container of this shape comprises a bottom plate, a peripheral side wall upwardly extending from the periphery of the bottom plate, and an opening peripheral edge encompassing an opening and outwardly extended from the upper edge of the peripheral side wall.
Further, a lid to be put on a container is manufactured also by molding a thin synthetic resin sheet into a lid shape. Some lids are molded into complicated shapes in order to have a good design. However, generally, a lid has an opening peripheral edge encompassing a lid opening and extended outwardly, obliquely downwardly or downwardly in order to engage with the upper edge of the peripheral side wall and the opening peripheral edge of the container.
A container or a lid molded of a thin synthetic resin sheet is separated from the sheet by cutting the above-mentioned opening peripheral edge thereof. Therefore, the opening peripheral edge is elongated in straight and/or smoothly curved fashion along the outline of the container or the lid.
As a result, there is a problem that such an opening peripheral edge elongated along the outline of a container or a lid is apt to hurt user's hand or finger at the time of using the container or the lid since the material sheet thereof is thin.
Further, at the time of putting an article into such a container and wrapping the same with a wrapping film, the wrapping film is rubbed against the opening peripheral edge and sometimes cut. Therefore, there is a problem that much time and labor is required to wrap such a packaging container with a wrapping film.
SUMMARY OF THE INVENTIONTherefore, an object of the present invention is to solve the above-mentioned problems by providing a method for manufacturing a safe and easily treatable packaging container having an opening peripheral edge of an improved structure.
A packaging container according to the present invention is one whose opening peripheral edge encompassing an opening is cut, and the container is characterized in that the opening peripheral edge thereof is not elongated straight but is finely corrugated in the longitudinal direction.
Even though a packaging container according to the present invention is molded of a thin synthetic resin sheet, the finely corrugated opening peripheral edge in the longitudinal direction thereof has a lower sharpness than a thin peripheral edge elongated straight has. As a result, if user's hand, finger or the like is rubbed against the opening peripheral edge, the hand, finger or the like can be prevented from being hurt.
Further, even if a wrapping film is stretched on and rubbed against the opening peripheral edge, the wrapping film can be prevented from being broken.
In this embodiment, the container body 1 is explained as a packaging container. The container body 1 has a bottom plate 20 and a peripheral side frame (peripheral side wall) 10 standing obliquely outwardly at the periphery of the bottom plate 20. The bottom plate 20 has, for example, a substantially rectangular shape with rounded four corners. Therefore, the container body 1 has, as a whole, a shape of a deep rectangular dish. And the upper end of the peripheral side frame 10 defines an opening of the container body 1. An outwardly extended flange 11 is formed at the upper end of the peripheral side frame 10. The flange 11 constitutes a peripheral flange encompassing the upper end of the peripheral side frame 10, namely, encompassing a container opening. The flange 11 serves for reinforcing the container opening both in the inward and outward directions.
In the embodiment shown, the outer peripheral edge 11a of the flange 11 is finely corrugated when seen in the vertical direction. In this case, the difference d between the top and the bottom of the corrugated shape (waveform) is not more than 0.5 mm. Further, the pitch p (the distance between the tops or bottoms) of the corrugated shape (waveform) is about 1 mm.
In this respect, the difference d between the top and the bottom of the waveform may be in the range of 0.2-1.0 mm and is preferably not more than 0.5. And the pitch p may be in the range of 0.5-5.0 mm and is preferably about 1.0 mm.
By determining the size of the waveform in the above-mentioned value ranges, user's hand and finger can be prevented from being hurt and the wrapping film can be prevented from being broken by the outer peripheral edge 11a of the flange 11.
The direction of the corrugation of the outer peripheral edge 11a of the flange 11 may be a horizontal direction in which case the waveforms can be seen in plan view as in the above-mentioned embodiment, or may be a vertical direction in which case the waveforms can be seen in the lateral (horizontal) direction as in this embodiment.
Otherwise, by combining the above-mentioned embodiment and this embodiment, the outer peripheral edge 11a of the flange 11 may be complexly corrugated both in the lateral (horizontal) and vertical directions.
Anyway, since the outer peripheral edge 11a of the flange 11 is finely corrugated, the outer peripheral edge 11a does not form a straight edge such as one cut from a flat thin resin sheet but forms a finely waved or corrugated edge. As a result, the outer peripheral edge 11a of the flange 11 according to the present invention can prevent user's hand and finger from being hurt and prevent a packaging film from being broken by contacting the outer peripheral edge.
As shown in
In the case of this embodiment, the outer peripheral edge 11a of the flange 11 is also not straight but corrugated, so that the sharpness with respect to user's hand and finger and a packaging film can be reduced. The difference d between the top and the bottom of the corrugated shape (waveform) is not more than 0.5 mm. Further, the pitch p (the distance between the tops or bottoms) of the corrugated shape (waveform) is about 1 mm.
In the above-mentioned embodiments, described are package containers having a corrugated opening peripheral edge encompassing the opening of the container body 1. However, the present invention can be applied not only to the container body 1 but also to an opening peripheral edge of a lid to be put on the container body 1. That is, when a packaging container, especially one for packaging food or the like is molded of a thin synthetic resin sheet, not only a container body thereof but also a lid to be fitted to the container body is manufactured. Similarly to the case of the container body, the opening peripheral edge of the lid is cut out of a synthetic resin sheet. Therefore, by forming the opening peripheral edge of the lid in a corrugated shape, the opening peripheral edge of the lid can have a soft touch instead of a sharp touch.
As shown in
Further, when the projection 15 is projected, the outer peripheral edge of the projection 15 is preferably corrugated.
In the above-mentioned description with reference to
In the above-mentioned embodiments, provided is an outwardly extended flange at the opening of the container body or the lid. However, if there is no flange at the periphery of the opening of the container body or the lid, the opening peripheral edge can be corrugated.
FIGS. 7(A)-(C) are illustrative vertically sectional views of three kinds of container bodies. In the case that a flange 11 is provided at the periphery of the opening as shown in
Now, a method for manufacturing a container body of
A synthetic resin sheet from a whole roll is fed on a metal mold P1 for molding. The sheet is deformed in line with the shape of the metal mold P1, then transferred to a trimming die and cut by a cutting machine having e.g. a Thomson blade, whereby a molded container is separated from the sheet.
One example of a metal mold P1 for molding is shown in
If a flange has been corrugated in the vertical direction as shown in the embodiments of
It is preferable that an opening peripheral edge of a packaging container is cut in an atmosphere temperature range of 15° C.-55° C. This is because if the temperature of a molded product is not higher than 15° C., the molded product is apt to be cracked to become a bad product, and on the contrary, the temperature of a molded product is not lower than 55° C., the molded product is apt to be softened and deformed.
Although embodiments of the present invention have been described and illustrated in detail, it is clearly understood that these are by way of illustration and example only and are not to be taken by way of limitation, and the spirit and scope of the present invention are limited only by the terms of the appended claims.
This application corresponds to the Japanese Patent Application No. 2002-226431 filed in the Japan Patent Office on Aug. 2, 2002 and the Japanese Patent Application No. 2003-103250 filed in the Japan Patent Office on Apr. 7, 2003, and the whole disclosures of these Japanese applications are incorporated in this application by citation.
Claims
1. A packaging container molded resin sheet comprising:
- a container body having a bottom plate, a peripheral side wall standing at a periphery of the bottom plate, and an opening provided at an upper end of the side wall;
- a flange at the upper end of the peripheral side wall, which is extended outwardly from the upper end of the peripheral side wall, which has minute projections and recesses molded therein from opposing surfaces of the flange; and
- an outer peripheral edge of the flange including a corrugation obtained by cutting the flange with a cutting blade along a cutting line crossing a number of the minute projections and minute recesses.
2. A packaging container in accordance with claim 1, wherein cutting of the flange with the cutting blade is carried out in an atmosphere temperature range 15° C. to 55° C.
3. A packaging container according to claim 1, in which the difference between the top and the bottom of a waveform of the corrugation is in the range of 0.2-1.0 mm and the pitch (the distance between the tops or the bottoms of the waveforms) of the corrugation is in the range of 0.5-5.0 mm.
4. A packaging container according to claim 3, in which the difference between the top and the bottom of the waveform of the corrugation is not more than 0.5 mm and the pitch (the distance between the tops or the bottoms of the waveforms) of the corrugation is not more than 1.0 mm.
5. A lid molded of a synthetic resin sheet in a predetermined shape having an opening, and configured to be put on a packaging container,
- the lid including a flange projecting outwardly from the opening and having a plurality regularly formed minute surface variations,
- each surface variation being a minute projection or a minute recess, arcuate in vertical cross section, and arranged in a pattern of at least two rows and at least two columns,
- an outer peripheral edge of the flange forming a vertically corrugated edge defined by a line crossing the minute projections or minute recesses.
6. The lid according to claim 5, wherein the surface variations include a plurality of minute projections having:
- a height that differs by not more than 0.5 mm from a vertical distance between a top and a bottom of a waveform of the vertically corrugated edge; and
- a pitch, which is equal to a distance between tops and bottoms of the waveform, of not more than 1.0 mm.
7. The lid according to claim 6, wherein the surface variations include a plurality of minute recesses having:
- a depth that differs by not more than 0.5 mm from a vertical distance between a top and a bottom of a waveform of the vertically corrugated edge; and
- a pitch, which is equal to a distance between tops and bottoms of the waveform, of not more than 1.0 mm.
8. The lid according to claim 5, said outer peripheral edge comprising alternating said minute projections and said minute recesses.
9. The lid according to claim 5, wherein said flange is provided with regularly formed minute projections and minute recesses, both the minute projections and the minute recesses being arcuate in vertical cross section.
10. A lid molded of a synthetic resin sheet and configured to be put on a container, the lid comprising:
- a flange formed at a peripheral portion of the lid, which extends outwardly from the peripheral portion, including minute projections and recesses throughout the flange; wherein:
- an outer peripheral edge of the flange forms a vertically minute corrugation defined by a cutting line crossing a number of minute projections and a number of minute recesses formed throughout the flange.
11. The lid according to claim 10, wherein:
- the minute projections and recesses throughout the flange are made by molding a sheet using a metal mold, at least a part of the metal mold configured to mold the flange formed with minute projections and recesses; and
- the outer peripheral edge of the flange is obtained by cutting the flange with a cutting blade to form the cutting line.
12. The lid according to claim 10, said minute projections having a difference between a top and a bottom of a waveform of the vertically minute corrugation of not more than 0.5 mm and a pitch (a distance between tops and bottoms of the waveform) of the vertically minute corrugation of not more than 1.0 mm.
13. The lid according to claim 12, said minute recesses having a difference between a top and bottom of a waveform of the vertically minute corrugation of not more than 0.5 mm and a pitch (a distance between the tops and the bottoms of the waveforms) of the vertically minute corrugation of not more than 1.0 mm.
14. The lid according to claim 10, both the minute projections and the minute recesses being arcuate in vertical cross section.
Type: Application
Filed: Mar 27, 2009
Publication Date: Jul 30, 2009
Applicant: FP CORPORATION (Hiroshima)
Inventor: Yoshinori Fujii (Hiroshima)
Application Number: 12/382,991
International Classification: B65D 43/08 (20060101); B65D 1/44 (20060101);