JPH0536308B2 - - Google Patents

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a lid for a container containing food, oil, medicine, etc., which is made of plastic and can be easily opened without using any equipment such as a can opener. It's about sex.

``Prior art'' Conventional plastic easy-open lids (hereinafter referred to as easy-open lids) are shown in Figures 14 and 15.
There is one shown in the figure.

The easy-to-open lid shown in FIG. 14 is approximately disc-shaped and is made of a gas barrier layer 1 that prevents gas from passing through and a plastic layer 2 laminated thereon. The outer peripheral part of this easy-to-open lid is a flange part 3,
A score 6 is provided at a position slightly inward from the flange portion 3 over the entire circumference. In this easy-to-open lid, the score 6 is formed to have a V-shaped cross section.

Furthermore, in the case of the easy-open lid shown in FIG. 15, the score 6 is formed by exposing the gas barrier layer 1.

These easy-to-open lids, as shown in Figure 16,
It is used by being fixed to the periphery 5 of the opening of the can container main body 4 by the flange part 3. In these easy-to-open lids, the portion surrounded by the score 6 is an opening 7, and an opening tab 8 is attached to this opening 7. The opening 7 of these easy-to-open lids is opened by pulling up the ring portion 9 of the opening tab 8 and tearing the score 6 portion.

``Problem to be solved by the invention'' In all of these conventional easy-open lids, the portion with a score of 6 is formed thin, so the portion with a score of 6 may be damaged or damaged during the distribution stage. It was easy to get damaged, and there were concerns about the reliability of the airtight seal.

In addition, in the conventional easy-to-open lid, when a shock is applied to the can container with the lid attached, such as by dropping, the load of the contents of the container is concentrated on the score 6 portion of the lid, and the score 6 portion is It was easy to tear, and I was worried about its strength when dropped.

Therefore, to address these issues, score 6
If the portion is made thick, the force required to open the package will be large, causing a problem in which the ease of opening the package will be impaired.

As described above, with the conventional easy-to-open lids, there have been complaints that it is difficult to achieve both airtight reliability, can drop strength, and ease of opening.

``Object of the Invention'' The present invention was made in view of the above-mentioned circumstances, and an object thereof is to provide an easy-to-open plastic lid that is excellent in airtight reliability and can-drop strength, and is also satisfactory in unsealability.

"Means for Solving the Problems" The easy-to-open plastic lid of the present invention has a plastic layer laminated on a gas barrier layer that prevents gas from passing through, and an inner periphery of the plastic layer surrounded by a score. and an outer periphery thereof, and an easy-to-open plastic lid having an opening tab attached to the inner periphery so that its tip is located near the score, the inner periphery of the plastic layer The outer circumferential side of the part and the inner circumferential side of the outer circumferential part are curved or bent in the thickness direction so as to fit into each other, and are butted against each other, and furthermore, the outer circumferential edge part of the inner circumferential part The lower surface and the lower surface of the inner peripheral edge portion of the outer peripheral portion are located at the same height, and at least both of these lower surfaces are bonded to the gas barrier layer.

The plastic layer of the plastic easy-open lid (hereinafter abbreviated as easy-open lid) of the present invention can be formed from various moldable plastics. Specific examples include polyethylene resin,
Various types of resins include polyolefin resins such as polypropylene resins, ethylene-vinyl acetate copolymer resins, styrene resins such as polystyrene resins, styrene-butadiene copolymer resins, styrene-butadiene-acrylonitrile resins (ABS resins), and acrylic resins. can be mentioned. It is also possible for the inner and outer peripheries of the plastic layer to be made of different materials.

In the easy-to-open plastic lid of the present invention, the plastic layer has a shape that is curved or bent in its thickness direction so that the outer circumferential side of the inner circumferential part and the inner circumferential side of the outer circumferential part fit into each other. It is formed. Various shapes can be adopted as such a shape, such as one having a concave surface and the other having a convex surface, but especially an underside that prevents the inner circumference of the easy-to-open lid from coming off outward. A cut-shaped one is preferable. Furthermore, if the fit between the inner circumferential part and the outer circumferential part is too tight, the unsealing property will be impaired, and if the fit is too loose, the strength against dropping cans will not be sufficiently improved, so it is important to strike a balance between the two. Specific examples of this fitted state include shapes as shown in FIGS. 2 to 13.

The gas barrier layer of the easy-to-open lid of the present invention can be formed of a known material with low gas permeability, such as a metal foil such as aluminum foil, or a laminated sheet made by laminating a plastic film on a metal foil. can.

This easy-open lid can be manufactured by various methods. A preferred manufacturing method is to mold the outer and inner parts of the plastic layer separately, then combine and integrate them, and separately shape a sheet with gas barrier properties to create a gas barrier layer. Then, there is a method of welding these plastic layers and the gas barrier layer.

``Operation'' To open the easy-open plastic lid of the present invention, first push inward the portion of the inner periphery near the score. Then, the inner circumferential portion and the outer circumferential portion are disengaged, and then tearing force is applied to the gas barrier layer at the score portion, causing the gas barrier layer to be cut and opened.

In an easy-to-open plastic lid with such a structure, the inner and outer peripheries of the plastic layer are formed so that they fit together at the score, so the gas barrier layer is also formed by the plastic layer at the score. covered and protected.

In addition, in this easy-open plastic lid, the inner and outer peripheries of the plastic layer are fitted in the score part, so when the can is dropped, part of the impact applied to the score part is absorbed by the plastic layer. The stress applied to the gas barrier layer is also alleviated.

Furthermore, in the easy-to-open plastic lid of the present invention, as described above, the outer circumferential side of the inner circumferential portion of the plastic layer and the inner circumferential side of the outer circumferential portion are butted against each other, so that the distance between the inner circumferential portion and the outer circumferential portion is It is narrow, and the lower surface of the outer periphery of the inner periphery and the lower surface of the inner periphery of the outer periphery are located at the same height, and both of these lower surfaces are bonded to the gas barrier layer, so when opening the package as described above, , shearing force acts on the gas barrier layer.

Furthermore, in the easy-to-open plastic lid of the present invention, when the lid is alone, the lower surface of the outer periphery of the inner periphery of the plastic layer and the lower surface of the inner periphery of the outer periphery are bonded to the gas barrier layer. During manufacturing, the plastic layer and gas barrier layer can be firmly supported and crimped together.

EXAMPLES Hereinafter, the plastic easy-open lid of the present invention will be described in detail with reference to the drawings. Note that the same components as those in the conventional example are given the same reference numerals to simplify the explanation.

Example 1 FIG. 1 shows a first example of the easy-to-open lid of the present invention.

This easy-to-open lid is made by laminating a plastic layer 10 with a thickness of 1 mm and a gas barrier layer 1 with a thickness of 60 μm. The plastic layer 10 of this easy-open lid is made of polypropylene and is separated by a score 11 into an inner periphery 12 and an outer periphery 13. This plastic layer 10
As shown in an enlarged view in FIG. 2, a protruding strip 14 having a semicircular cross section is formed along the entire circumference of the inner circumferential portion 12 of the inner circumferential portion 12 . On the other hand, a groove 15 having a semicircular cross section is formed in the inner circumferential edge portion of the outer circumferential portion 13, into which the protruding strip 14 of the inner circumferential portion 12 is fitted.
The depth of this groove 15 was 0.5 mm and the width was 0.5 mm. In the inner circumference 12 of this plastic layer 10,
An opening tab 8 is attached.

The gas barrier layer 1 is formed of a laminated sheet in which a 20 μm thick polypropylene film is laminated on the front and back surfaces of a 20 μm thick aluminum foil. The gas barrier layer 1 and the plastic layer 10 are welded together.

Next, a method of manufacturing this easy-to-open lid will be explained.

First, a gas barrier layer 1 was created by press-molding a laminated sheet. Further, the inner circumferential portion 12 and the outer circumferential portion 13 of the plastic layer 10 were separately molded by injection molding polypropylene resin. At this time, a mold in which a cavity for molding the inner peripheral part 12 and a cavity for molding the outer peripheral part 13 were formed together was used, and both were injection molded at the same time.

Next, the injection-molded inner circumferential part 12 and outer circumferential part 13 were combined, and then overlapped with the gas barrier layer 1 and high-frequency welded. Next, the opening tab 8 was ultrasonically welded to the inner peripheral portion 12 of the plastic layer 10 to complete an easy-opening lid.

In the manufactured easy-to-open lid, when the ring portion 9 of the opening tab 8 was pulled up, the protruding stripes 14 on the inner circumferential portion 12 came off from the grooves 15 on the outer circumferential portion 13, and the gas barrier layer 1 was subsequently pushed and torn. It was opened. The force required at this time was equivalent to that of a conventional easy-to-open lid.

Next, put this easy-to-open lid on the can filled with water and the 15th
When each of the conventional easy-open lids shown in the figure was attached and dropped, it was found that the easy-open lids had approximately 20% higher strength when dropped than the conventional ones.

Example 2 An easy-to-open lid was manufactured that differed from Example 1 in that the fitting between the inner circumferential part 12 and the outer circumferential part 13 was structured as shown in FIG. Examined.

In this easy-open lid, a groove 15 having a rectangular cross section is formed in the lower part of the inner edge of the outer circumference 13, and a protrusion 14 that fits into the groove 15 is formed on the inner circumference 12. It protrudes from the lower part of the outer peripheral end.
The thickness of the plastic layer 10 of this easy-open lid is:
1 mm, the thickness of the protrusion 14 was 0.5 mm, and the protrusion length of the protrusion 14 was 1 mm.

When this easy-open lid was opened, it was found that the lid was easier to open than that of Example 1.

In addition, the drop strength is approximately 10% compared to conventional products.
It was improving.

"Effects of the Invention" As explained above, the easy-to-open plastic lid of the present invention provides the following effects.

In the easy-to-open plastic lid of the present invention, the outer peripheral side of the inner peripheral part of the plastic layer and the inner peripheral side of the outer peripheral part are formed in a shape that is curved or bent in the thickness direction so that they fit into each other. Since the inner circumferential portion and the outer circumferential portion are butted against each other, the score that separates them is extremely narrow and curved in the thickness direction. Therefore, in this easy-to-open plastic lid, the gas barrier layer is protected from the outside by the plastic layer even in the score portion. Therefore, the easy-open plastic lid of the present invention can reliably prevent the gas barrier layer from being damaged or tampered with in the portion where the score is provided, and has excellent airtight reliability.

Furthermore, in the easy-to-open plastic lid of the present invention, as described above, the plastic layer has a shape that is curved or bent in the thickness direction so that the outer circumferential side of the inner circumferential part and the inner circumferential side of the outer circumferential part fit into each other. and are butted against each other so that the inner and outer peripheries of the plastic layer fit together. As a result, a portion of the impact applied to the score portion when the can is dropped is also absorbed by the plastic layer, and the force applied to the gas barrier layer when the can is dropped is alleviated. Therefore, the easy-to-open plastic lid of the present invention has excellent can-drop strength and vibration resistance.

Furthermore, in the easy-to-open plastic lid of the present invention, as described above, the outer circumferential side of the inner circumferential portion of the plastic layer and the inner circumferential side of the outer circumferential portion are butted against each other, so that the distance between the inner circumferential portion and the outer circumferential portion is Moreover, the lower surface of the outer peripheral edge of the inner peripheral part and the lower surface of the inner peripheral edge of the outer peripheral part are located at the same height, and these lower surfaces are close to each other and are bonded to the gas barrier layer, so that it is difficult to open the package as described above. At this time, shearing force acts on the gas barrier layer. Therefore, in the easy-to-open plastic lid of the present invention, the gas barrier layer exhibits very little elongation when broken, and the gas barrier layer can be broken sharply, making it easy to open.

Furthermore, in the easy-to-open plastic lid of the present invention, when the lid is alone, the lower surface of the outer periphery of the inner periphery of the plastic layer and the lower surface of the inner periphery of the outer periphery are bonded to the gas barrier layer. During manufacturing, the plastic layer and the gas barrier layer can be firmly supported and crimped together. Therefore, according to the easy-to-open plastic lid of the present invention, the plastic layer can be evenly bonded to the gas barrier layer.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the easy-to-open plastic lid of the present invention, and FIG. 2 is a cross-sectional view showing an enlarged view of the fitting shape between the inner and outer peripheral portions of the plastic layer of the same embodiment. 3 to 13 are cross-sectional views showing other examples of the fitting shape between the inner and outer peripheral parts of the plastic layer, and FIG. 14 is a cross-sectional view showing a conventional easy-open plastic lid. 15 is a cross-sectional view showing the main parts of another example of a conventional plastic easy-open lid, and FIG. 16 is a cross-sectional view showing a can container equipped with a conventional plastic easy-open lid. 1...Gas barrier layer, 10...Plastic layer, 11...Score, 12...Inner peripheral part, 13...
Outer periphery, 14... Convex strip, 15... Concave groove.

Claims (1)

[Scope of Claims] 1. A plastic layer is laminated on a gas barrier layer that prevents gas permeation, and the plastic layer is separated into an inner peripheral part surrounded by a score and an outer peripheral part outside the score, In the plastic easy-to-open lid, in which an opening tab is attached to the inner periphery so that the tip thereof is located near the score, the outer periphery side of the inner periphery of the plastic layer and the inner periphery side of the outer periphery are mutually connected. They are curved or bent in the thickness direction so as to fit into each other, and are butted against each other, and the lower surface of the outer peripheral edge portion of the inner peripheral portion and the lower surface of the inner peripheral edge portion of the outer peripheral portion are at the same height. 1. An easy-open plastic lid, characterized in that the plastic lid is located on the gas barrier layer, and at least both lower surfaces thereof are bonded to the gas barrier layer.