JPH0314452A - Double seam can lid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a double-sealed can lid for use with metal plates that are double-sealed to the flange portion of a can body.

(Prior art) Conventionally, double-sealed can lids were held on their inner surface.
It is shaped from a metal plate material provided with a coating resin layer, and has a curled part around the entire circumference of the center panel of the can lid, and a sealing compound is applied to the surface of the protective coating resin layer of the curled part. ing.

When the curled portion is double-sealed to the flange portion of the can body, the curled portion 3 of the can Ml is double-sealed to the flange portion of the can body, as shown in FIG.
The flange portion 5 of the flange portion 5 is bent and wrapped around the shaped body hook portion 6 through sealing compound 7, and the body hook portion 6 is appropriately long and the curled portion 3 is wrapped around the body hook portion 6. The cover footer portion 8 formed by the above must be inserted with an appropriate length, and the cover hook portion 8 and the body hook portion 6 must form an overlap portion 9 with an appropriate width.

Usually, such can lids are attached to two-piece cans or three-piece cans.
When double seaming is performed, seaming is performed using a seaming device as shown in Fig. 2, and the can I is placed in the seaming chuck lO of the device
1 and lift the can body 4 placed on the lifter l1, and as shown in FIG.
The sealing compound 7 is brought into contact with the portion of the curled portion 3 on which the sealing compound 7 is applied, and the lid is pressed at a predetermined pressure. next,
As shown in FIG. 4, the first seaming roll 12 is brought into contact with the curled portion 3 from the side and pressed, and as shown in FIG. I'm going to have a good time. Next, in the same manner as described above, the curled portion 3 is pressed by the second seaming roll 13 and formed along the shape of the opening, so that the flange portion 5 is in a hanging state as shown in FIG. At the same time, the body hook part 6 is formed, and the tip side of the curled part 3 is caught between the body hook part 6 and the can body 4, and the cover hook part 8 tightly sandwiched therebetween is formed, resulting in double winding. It is tightened. Further, at this time, the sealing compound 7 applied to the curled portion 3 is compressed and enters the space defined by the curled portion 3 and the flange portion 5, sealing the double-sealed portion.

However, for can lit, the first seaming roll ■2 and the second
Since the curled portion 3 is directly pressed by the seaming roll 13, the cover footer portion 8 is easily shaped to an appropriate length, but the flange portion 5 of the can body 4 follows the shape of the curled portion 3 and is bent. Therefore, as shown in FIG. 7, the body hook portion 6 may not be formed to an appropriate length.

For this reason, if the length of the body hook part 6 is short, the width of the overlap part 9 between the body hook part 6 and the cover hook part 8 becomes narrow, resulting in a disadvantage that the sealing performance of the can container is deteriorated. In order to solve this problem, there are methods such as changing the shape of the can III and the shape of the flange portion 5 of the can body 4, or increasing the seaming lid pressure of the seaming device seaming device seaming lid 11, but usually the latter method is used. measures have been taken.

Although it is possible to appropriately lengthen the body hook portion 6 using such a method of increasing the lifter pressure, in this case, a strong pressing force is also applied to the can body. In particular, can bodies formed using thin metal plates made possible by recent resource-saving measures have a thin body and other parts that are low in strength, so there is a problem that the can body deforms when the lifter pressure is increased. When the thickness of the can body is reduced, it is difficult to properly perform double seaming.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned disadvantages and provides a double-sealed can that can properly double-seal the flange portion of a can body using a thin metal plate. It is intended to provide a cover.

(Means for Solving the Problems) In order to achieve the above object, the present invention consists of a can material in which a protective coating resin layer is provided on at least the inner surface of a metal plate material for a can lid, and the central panel portion and the In the can lid for double seaming, which has a curled part curved around the entire circumference of the panel part, and a sealing compound is applied on the protective coating resin layer of the curled part, the can lid is provided on at least the curled part of the can lid. The protective coating resin layer is characterized in that it contains 0.3 to 4.0% by weight of polyethylene wax based on the solid content of the resin.

When double-sealing the curled portion of the can lid to the flange of the can body, when the flange is brought into contact with the relatively soft portion of the curled portion coated with sealing compound and pressed, the flange portion It bends when pressed against the
At this time, if the flange part is bent smoothly along the shape of the curled part, the length of the bent body hook part of the flange part will be an appropriate length, and if it is not bent smoothly, the length of the body hook part will be shortened.

Therefore, by containing an appropriate amount of polyethylene wax in the protective coating resin layer of the curled part, when the flange part is pressed against the curled part and bent, the resistance force at the contact area between the flange part and the curled part can be reduced. Thus, the flange portion can be bent to smoothly follow the shape change of the curled portion, and the length of the body hook portion can be set to an appropriate length.

As the polyethylene wax, a polyethylene copolymer, a modified polyethylene, or the like can be used alone or a blend thereof. In addition, the content in the protective coating resin layer is at least relative to the protective coating resin layer provided on the curled part, or in the case where the protective coating resin layer is formed by multiple resin layers, the content on the outermost surface thereof. The solid content of the resin in the resin layer is preferably in the range of 0.3 to 4.0% by weight, more preferably 0.5 to 4.0% by weight. If the content is less than 0.3% by weight, the resistance force will be less reduced when the flange portion contacts the curled portion, and the body hook portion may not have an appropriate length. In addition, when the content exceeds 4.0% by weight,
Wax precipitates on the surface of the protective coating resin layer, and wax adheres to various devices and conveyance devices in the lid manufacturing process, reducing the accuracy of lid processing and making the lid easy to stain, and causing damage to the protective coating resin layer. The adhesion between the can and the sealing compound applied to its surface deteriorates, and the sealing performance of the can container also deteriorates.

In addition, aluminum alloy material, tin plate material, stain-free steel material, etc. can be used as the metal plate material processed into the can lid, but aluminum alloy material with excellent seaming workability into the can lid is preferable. be.

In addition, the protective coating resin layer of the metal plate can be formed by coating with thermosetting epoxy resin paint, vinyl chloride resin organosol paint, thermosetting vinyl resin paint, thermosetting polyester resin paint, etc. Alternatively, it can be provided by laminating a thermoplastic resin film, but among the above, in consideration of the protective effect of the metal plate material and the influence on the contents, painting with thermosetting epoxy resin paint is particularly suitable. ing.

(Function) According to the above means, the can lid is double-sealed to the flange portion of the can body because the protective coating resin layer of the curled portion contains an appropriate amount of polyethylene wax. edge,
When bending the flange by press-contacting the flange at the curl, the resistance force at the contact area between the curl and the flange is reduced, the flange smoothly follows the change in shape of the curl during tightening, and the flange is fully tightened. This makes it possible to create a body hook portion with a long length.

For this reason, the can lid is made of thin metal plates for the can body and can lid itself, so that the flange part follows the shape of the curled part and bends easily without applying strong pressing force during double seaming. To enable double seaming with a body hook part of an appropriate length in a flange part, without deforming the can body and can lid itself due to the pressing force.

(Example) An example of implementation of the present invention will be described.

The can lid of this example uses a can material in which a protective coating resin layer containing polyethylene wax is provided on the inner surface of the can of an aluminum alloy plate with a thickness of 0.32n+m. It is punched and stamped using a certain device to form a can lid shape, and like a conventional can lid, it has a curled portion 3 around the entire circumference of the central panel portion 2 of the can M1, as shown in the third figure. A sealing compound 7 is applied onto the protective coating resin layer of the curled portion 3 in order to improve the adhesion with the flange portion 5 of the can body 4 after seaming.

The protective coating resin layer is formed using an epoxyphenol resin paint obtained from bisphenol A and epichlorohydrin to a film thickness of 4μ, and the content of polyethylene wax in the paint is determined as in the first example. There were two types, 1.0% by weight and 1.5% by weight as the second example, based on the resin solid content. In addition, a styrene-butadiene sealing compound is used as the sealing compound. The can lid 1 thus formed into a can lid shape is tightened as shown in FIGS. 3 to 6 by a known can lid tightening device shown in FIG. mf
1 aluminum DI can was double seamed. This 2
The settings for the can lid seaming device during heavy seaming are as follows: lifter pressure is 80 kg/cJ, seaming chuck height is 11, which is the distance between seaming chuck 10 and lifter 11.
The thickness of the curled portion 3 after being tightened by the first tightening roll l2 was set to 2.30 mm.

Next, a can lid having the same shape as in the first and second embodiments was manufactured using a can material in which only the content of polyethylene wax in the protective coating resin layer was outside the range of the present invention, and a can lid tightening device was installed. The can bodies were double seamed with the same settings, and the lengths of the body hook portion 6 and cover hook portion 8 were compared. The results are shown in Table 1.

Table 1 In Table 1, the can lid of Comparative Example 1 has a polyethylene wax content in the protective coating resin layer of 0.2% by weight, which is less than the range of the present invention than in Examples 2 and 2. . Although not shown in Table 1, Comparative Example 2 contains 5.0% polyethylene wax, which is beyond the scope of the present invention.

In both the first and second examples, the body footer portion is formed longer than in Comparative Example 1, which has a small content of polyethylene wax, and exhibits excellent double seaming properties. this is,
This is because the protective coating resin layer contains an appropriate amount of polyethylene wax, and when the flange part is pressed and bent by the curl part pressed during double seaming, the contact area between the curl part and the flange part By reducing the resistance force, the flange portion smoothly follows the shape change of the curled portion and is bent to form a longer body hook portion. In addition, because the content of polyethylene wax in Comparative Example 2 was too high, the wax precipitated on the surface of the coating film of the protective coating resin layer, resulting in poor appearance.Also, the precipitated wax adhered to the lid making equipment, causing the process line to deteriorate. It was unsuitable for practical use as it contaminated the surface.

Therefore, in the case of the can lid of this embodiment, when double seaming is performed under the same conditions and at the same end lid pressure, the body hook portion is formed long in the flange portion, and the sealing performance of the can container can be improved. On the other hand, in order to shape the body hook part to the same length, it is possible to properly shape the body hook part by using a low lifter pressure, and even if the can body is made of a thin plate, the lifter Double seaming is possible without deforming the can body etc. due to pressure.

(Effects of the Invention) As is clear from the above description, the present invention provides double seaming of the can lid to the can body by containing an appropriate amount of polyethylene wax in the protective coating resin layer of the curled portion of the can lid. When the flange part of the can body is pressed against the curled part and bent to follow the shape of the curled part, the resistance force at the contact part between the curled part and the flange part is reduced, and even with a low pressing force, the winding can be prevented. The flange part smoothly follows and bends as the shape of the curled part changes during tightening, making it possible to form a body hook part of an appropriate length, making it possible to easily adjust the shape of the lifter even if the can body is made of thin plate. This has the effect of providing a can lid for double seaming that can be double seamed without deforming the can body or the like due to pressure.

[Brief explanation of drawings]

1 to 6 show an example of the implementation of the present invention.
The figure is a cross-sectional view showing the part where the curled part of a double-sealed can lid is double-sealed to the flange part, and Figure 2 shows when the curled part is double-sealed to the flange part by the can lid seaming device. 3 is a sectional view showing the state in which the flange portion is in contact with the force roll, and FIG. 4 is the state in which the curled portion is being wound around the flange portion by the first tightening roll. A cross-sectional view showing
Figure 5 is a cross-sectional view showing the state when the curl part is wrapped around the flange part by the first seaming roll, and Figure 6 is a cross-sectional view showing the state when the curl part is double-sealed to the flange part by the second seaming roll. FIG. Further, FIG. 7 shows a conventional example, and is a sectional view showing a portion where the curl portion is double-sealed to the flange portion. l...Double-sealing can lid 2...Central panel portion 2...Curl portion 6...Sealing compound FIG. 1 F I G. 3 F I G. 4 FIG. 2 FIG. 5 F I G. 6-361-

Claims (1)

[Claims] It is made of a can material in which a protective coating resin layer is provided on at least the inner surface of a metal plate material for a can lid, and has a central panel portion and a curled portion curved around the entire circumference of the panel portion, and the protective coating of the curled portion Sealing compound applied on the resin layer 2
In the can lid for heavy seaming, the protective coating resin layer provided at least on the curled portion of the can lid contains 0.3 to 4.0% by weight of polyethylene wax based on the solid content of the resin. This is a double-sealed can lid.