JP2001151232A - Easy open can lid for beverage can having excellent falling strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy open can lid for a beverage can having excellent falling strength. SOLUTION: An easy open can lid for a beverage can having excellent falling strength has an S-shaped cross section at a part other than the seam part of the can lid and the S-shaped cross-sectional part contains no opening guide line and is provided outside the opening guide line. The S-shaped cross section has such a structure that the central part thereof is superposed on the outer surface side of a can and the seam part is superposed on the inner surface side of the can or the planar shape of an S-shape is closed and it is desirable that the closed side is superposed on the outer surface side of the can and the opened side is superposed on the inner surface side of the can. The overlap length of the S-shape is desirably 0.5-3 mm and the thickness thereof is desirably below 6 mm. The easy open can lid comprises a metal plate having a thermoplastic resin film at least on the inner surface side of the can.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easy-open can lid for beverage cans, and more particularly to an easy-open can lid for beverage cans in which an opening is pushed or torn off with an attached tab or finger.

[0002]

2. Description of the Related Art An easy open end used for beverage cans, general food cans, and the like is used to tear off a part or almost all of an opening piece of a container lid with a handle to separate it from a can body. There are a tear-off system and a stay-on tub system which is left attached to the can body. The easy-open can lid is made of painted aluminum plate or steel plate, punched into the basic lid shape, put it on a flat lower die, and presses the upper die with a score cutting blade with a pointed cross section projecting into the opening contour shape. Thus, an opening guide line having an opening shape is formed in the material. In order to facilitate the opening of the can, it is necessary to press the score processing blade so that the depth of the opening guide line reaches about 1/2 to 2/3 of the thickness before processing.
If the depth of the opening guide line is too shallow, the openability is poor. If the depth of the opening guide line is too deep, there is a problem in that the opening guide line exhibits cracks due to an external impact.

To solve these problems, Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open Nos. Hei 18-201851 and Hei 4-201852 propose to provide a recess for absorbing a metal surplus in an opening piece to improve can openability and improve drop strength. In Japanese Patent Application Laid-Open No. 8-164935, there is a proposal to improve the drop strength by providing another weakening line on the rivet side opposite to the score to form an easily bent portion, but further improvement is required. That is the fact.

[0004]

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide an easy-open can lid for beverage cans in which even if the remaining score thickness is small, the drop strength is increased and the score is not easily cracked when dropped. Is to provide.

[0005]

Means for Solving the Problems The present inventors have conducted various studies in order to solve the above-mentioned problems, and as a result, the opening guide line was not included in portions other than the tightened portion, and the outside of the opening guide line was not included. By adding a portion having an S-shaped cross section to
It has been found that the drop strength can be improved even if the remaining score is thin. That is, the gist of the present invention is as follows. (1) It has an excellent drop strength, characterized in that it has an S-shaped cross-sectional shape in a part other than the part to be wound of the lid, and the S-shaped does not include the opening guide line and is outside the opening guide line. Easy-open can lid for beverage cans. (2) The easy-to-use beverage can having excellent drop strength according to the above (1), wherein the S-shaped cross-section is such that the center portion overlaps the outer surface of the can and the tightened portion overlaps the inner surface of the can. Open lid.

(3) The excellent drop described in (1), wherein the S-shaped planar shape is a closed shape, and the closed side overlaps the outer surface of the can and the open side overlaps the inner surface of the can. Easy-to-open can lid for beverage cans with strength. (4) The easy-open can lid for beverage cans having excellent drop strength according to (1) to (3), wherein the overlapping length of the S-shape is 0.5 mm or more and 3 mm or less.

(5) The easy-open can lid for beverage cans according to the above (1) to (4), wherein the thickness of the S-shape is less than 6 mm. (6) The easy-open can lid for beverage cans having excellent drop strength according to the above (1) to (5), wherein the portion having the S-shape is a perfect circle as a planar shape.

(7) An easy-open can lid for a beverage can having excellent drop strength according to the above (1) to (6), comprising a metal plate having a thermoplastic resin film at least on the inner surface side of the can. . (8) The easy-open can lid for beverage cans having excellent drop strength according to (1) to (7), comprising a metal plate having a thermoplastic saturated polyester resin film on at least the inner surface of the can. is there. In addition, "the closed side is the can outer surface side and the open side is the can inner surface side" described in (3) means a case where an S-shape is formed as shown in FIG.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The present inventors provide a score having a S-shaped cross-section outside the opening guide line without including the opening guide line in a portion other than the tightened portion as shown in FIG. 1 or FIG. It has been found that the drop strength can be improved even if the remaining thickness is thin. Excluding the opening guide line in the parts other than the winding part,
By providing a portion having an S-shaped cross section outside the opening guide line, the stress due to the impact and water hammer action at the time of drop is absorbed by the S-shaped portion, so that the impact and water at the time of drop It is considered that the stress due to the hammering action is dispersed to prevent the stress from being concentrated on the score portion, thereby improving the drop strength.

As shown in FIG. 1, the cross section of the S-shape is preferably such that the central portion is the outer surface 1 of the can and the tightening portion is the inner surface 2 of the can from the viewpoint of shock absorption. Further, the S-shaped planar shape is a closed shape, and the S-shaped cross-sectional shape in which the closed side overlaps the can outer surface side 1 and the open side overlaps the can inner surface side 2 is a desirable shape from the viewpoint of shock absorption.

FIG. 3 shows an S-shaped cross section.
It is a desirable shape that the overlap length of the character is 0.5 mm or more and 3 mm or less. The overlapping length of the S-shape indicates the distance between two vertices of the bend. If the thickness is less than 0.5 mm, the effect of absorbing the stress due to the impact and water hammer action at the time of drop becomes small, and it becomes difficult to form an S-shaped cross-sectional shape stably in processing. If it exceeds 3 mm, the effect of absorbing the stress due to the impact / water hammer action at the time of drop saturates, and a large amount of material is required to form the S-shape, which is not economically preferable. Further, it is desirable that the thickness of the S-shape is less than 6 mm. 6
If it is more than 2.5 mm, the workability of the tightening operation is deteriorated, and more preferably less than 2.5 mm.

Further, as shown in FIG. 4, it is desirable that the portion having the S-shape is a perfect circle as a planar shape in order to stably absorb the stress caused by the impact and water hammer action when dropped. Reference numeral 3 indicates an S-shaped portion. In addition, since the processing of the portion having the S-shaped structure becomes severe, a metal plate lid having a thermoplastic resin film on at least the inner surface side of the can is used for contents having severe corrosion resistance. It is desirable to ensure the corrosion resistance of the steel. Furthermore, that the thermoplastic resin film is a saturated polyester resin film, flavor properties,
It is desirable from the viewpoint of workability.

In the present invention, a steel plate, a surface-treated steel plate, an aluminum plate and an aluminum alloy plate can be used, and the steel plate is usually of a thickness t _O : 0.080 to 0.250 mm.
, Hardness (HR30T) 46-68, elongation:
Those having mechanical properties of about 10 to 60% are used. On the surface of this steel sheet, Sn, Cr, Ni, Al, Zn
A surface-treated metal plate which has been subjected to one or more types of metal plating and subjected to a chemical conversion treatment such as a chromate treatment can also be used.

[0014] The steel sheet used specifically,
0.5-3.0 g / m^Two Chemical treatment after tin plating
Tin plated steel sheet, adhesion amount 0.3-2.0g / m^Two Nickel
Nickel-plated steel sheet subjected to chemical treatment after plating, Sn
And 0.5 to 2.0 g / m2 as Ni adhesion amount, respectively.^Two ,
0.01-0.5 g / m^Two After plating in order of Ni, Sn
Chemically treated Sn / Ni plated steel sheet, metal Cr adhesion
Amount 50-200mg / m ^Two , Cr oxide 5-30 mg / m
^Two Called normal TFS (Tin Free Steel)
There is a chromium-chromate treated steel plate that has been removed.

The aluminum plate used in the present invention usually has a thickness t _{O of} 0.18 to 0.32 mm. Further, as the alloy composition, 5052, 5082,
5182, 5352, 5349, 5017 series with tempering H
19 is desirable. A surface-treated metal plate obtained by subjecting the aluminum plate to a chromate treatment, a zirconate treatment, or a phosphoric acid-chromic acid chemical conversion treatment can also be used. Further, the above-mentioned metal plate having a surface coated with a coating film or a thermoplastic resin film can also be used.

[0016]

Hereinafter, examples of the present invention will be described together with comparative examples. Aluminum plate of 0.30mm thickness and 0.19mm thickness
The conventional lid shown in FIG. 8 using a tinplate or TFS plate, and an easy-open can having an S-shaped cross-sectional structure based on this conventional lid at the portion shown in FIG. 4, FIG. 5, FIG. 6 or FIG. The lid was molded. Reference numeral 4 denotes a rivet, reference numeral 5 denotes a tab, and reference numeral 6 denotes an opening guide line. Further, an aluminum plate, a tin plate or a TFS plate was used in which a thermoplastic resin film of polyethylene terephthalate or nylon 12 and a thermosetting resin film of epoxy phenol were previously laminated. As for the overlapping of the S-shape, molding was performed as shown in FIG. 1 (the center of the lid is the outer surface of the can) and FIG. 2 (the lid end was the outer surface of the can).
The overlapping length of the S-shape is in the range of 0.4 to 3.5 mm,
The thickness of the character was in the range of 1.5 to 6.5 mm.

The aluminum plate has a score remaining thickness (plate thickness of the opening guide line portion) of 115 μm, and the steel plate has a score remaining thickness of 55 μm.
m, an easy-open can lid having a can lid diameter of 60 mm was formed.
In each of the molded easy-open can lids, 200 cans each of the contents and pure water were wound around a steel can with a can wall plate thickness of 0.1 mm having an internal volume of 350 ml as the contents. The degree of vacuum in the can was 40 cm of mercury.

[0018] The filling can is dropped on a wooden board by a single unit.
The drop strength was evaluated. Drop height is 80cm and 90c
Each of the 100 cans was evaluated with two levels of m. All the cans with a small score were counted, and the results are shown in Table 1 as the number of falling crack cans. Table 1 summarizes the evaluation results. As can be seen from this example, by applying the present invention, an easy-open can lid having excellent drop strength can be obtained.

[0019]

[Table 1]

[0020]

As described above, the easy-open can lid according to the present invention has an excellent effect that the drop strength is extremely good.

[Brief description of the drawings]

FIG. 1 is a diagram showing an S-shaped cross-sectional structure.

FIG. 2 is a diagram showing an S-shaped cross-sectional structure.

FIG. 3 is a diagram showing a cross-sectional dimension of an S-shape.

FIG. 4 is a view showing an S-shaped planar portion (a perfect circular shape).

FIG. 5 is a diagram showing an S-shaped planar portion (elliptical shape).

FIG. 6 is a diagram showing an S-shaped planar portion (boat-shaped shape).

FIG. 7 is a diagram showing an S-shaped planar portion (divided type).

FIG. 8 is a diagram showing a typical example of a conventional easy-open can lid for beverage cans.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Can outer surface 2 Can inner surface 3 S-shaped part 4 Rivets 5 Tab 6 Opening guide line

Claims (8)

[Claims] 1. An excellent drop strength, wherein the lid has an S-shaped cross-section at a portion other than the tightened portion, and the S-shaped portion does not include the opening guide line and is outside the opening guide line. An easy-open can lid for a beverage can having a. 2. A beverage can having an excellent drop strength according to claim 1, wherein the S-shaped cross-section is such that the central portion overlaps the outer surface of the can and the tightened portion overlaps the inner surface of the can. Easy-open can lid. 3. The excellent drop strength according to claim 1, wherein the S-shaped planar shape is a closed shape, and the closed side overlaps the outer surface of the can and the open side overlaps the inner surface of the can. Easy-open can lid for beverage cans. 4. The overlapping length of the S-shape is 0.5 mm or more and 3 m.
The easy-open can lid for beverage cans having excellent drop strength according to any one of claims 1 to 3, wherein the lid is not more than m. 5. The easy-open can lid for beverage cans having excellent drop strength according to claim 1, wherein the thickness of the S-shape is less than 6 mm. 6. The easy-open can lid for beverage cans having excellent drop strength according to claim 1, wherein the portion having the S-shape is a perfect circle as a planar shape. 7. A metal plate having a thermoplastic resin film on at least the inner surface of the can.
2. An easy-open can lid for beverage cans having excellent drop strength according to item 1. 8. The easy-open can lid for beverage cans having excellent drop strength according to claim 1, comprising a metal plate having a thermoplastic saturated polyester resin film on at least the inner surface side of the can.