JPH01279053A - Manufacture of container with metal lid - Google Patents

Abstract

PURPOSE:To obviate the need for application of corrective coating after stamping, by stamping a metal sheet into a metal lid, forming at least either an anticorrosion layer or thermoplastic resin layer on the inner surface of the metal lid and curling the peripheral edge of the metal lid around the flange of a plastic container body filled with its content. CONSTITUTION:An aluminum metal sheet is stamped into a metal lid 11 with the peripheral edge 12. The outer surface of the metal lid 11 is then coated with an outer coating material 21 and the inner surface thereof with an inner coating material 22. The outer coating may be applied before stamping. As the outer coating material 21, epoxy acryl layer is used and, as the inner coating material 22, the laminate of an anticorrosion layer 22a consisting of epoxy phenol and a thermoplastic resin layer 22b consisting of modified polyolefin is used. A container 10 with a metal lid is formed by curling the peripheral edge 12 of the metal lid formed as mentioned above around a flange 15 of a plastic container body 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a method for manufacturing a container with a metal lid, which comprises a plastic container body and a metal lid.

(Prior Art) Metal containers, such as metal cans, have various shapes, but can be classified into three-piece cans and two-piece cans based on the structure of the can body. A three-piece can, also known as a tin solder can, has a cylindrical body, lid, and bottom sealed with double seams.

On the other hand, a two-piece can is also called a stamped tin can, and has a structure in which the body and bottom (container body) are integrally molded, and the lid is double-sealed.

These metal cans are used as food packaging containers for various canned foods, juices, soft drinks, jams, dried foods, etc., and are rigid containers with particularly excellent sealing and preservation functions. However, metal cans have the following points to be improved. That is, (1) Since it is a metal can, there is a limit to its weight reduction.

■ If it is crushed by an impact, it will not recover and will be deformed.

■ Compared to plastic containers, the energy cost of manufacturing them is higher.

■ If the display effect of the container exterior is made of metal, it cannot be changed freely, and the only means of exterior packaging is printing.

■ It is impossible to create transparent containers that allow the contents to be checked without opening the can.

In order to solve these drawbacks of conventional metal cans,
Containers with metal lids are being considered, which are made by attaching a metal lid to a plastic container body.

Furthermore, when a metal lid is attached to a plastic container body, the peripheral edge of the metal lid is wrapped around the flange portion of the container body.

By the way, the metal lid of a container with a metal lid is created by applying a front coat and a back coat to both sides of a metal plate sheet made of aluminum or tinplate, and then press-molding the metal plate sheet.

The coating applied to both sides of this metal plate sheet is as follows:
Generally, an epoxy acrylic layer is used for the front coat, and an epoxy phenol layer is used for the back coat.

(Problems to be Solved by the Invention) As described above, the metal lid of a container with a metal lid is created by press-molding a metal plate sheet coated on both sides.

However, when a metal plate sheet is press-formed, cracks may occur in the front coat and back coat applied to both sides of the metal plate sheet due to this press-forming. In particular, the half-cut score section for easy open is prone to cracking. When cracks occur in this way, the contents inside the container with a metal lid reach the metal plate through the cracks in the back coat and corrode the metal plate.

Therefore, in order to prevent corrosion of the metal plate, a repair coat is further applied on the back coat of the metal lid after press forming to prevent corrosion from cracks that occur in the back coat.

However, application of such a bare coat adds a new work process, resulting in an increase in manufacturing time and manufacturing cost.

The present invention has been made in consideration of these points,
It is an object of the present invention to provide a method for manufacturing a container with a metal lid, which eliminates the need to apply a repair coat after press molding and can reduce manufacturing time and manufacturing cost.

[Structure of the invention]

(Means for Solving the Problem) The present invention creates a metal lid by press-molding a metal plate sheet, and then applies at least one layer of a corrosion-resistant layer or a heat-melting resin layer to the back side of the metal lid, This method of manufacturing a container with a metal lid consists of wrapping the metal lid around the plastic container body containing the contents.

(Function) According to the present invention, since at least one layer of the anti-corrosion layer or the hot-melt resin layer is applied to the back surface of the metal lid created by press molding, cracks do not occur in these layers due to press molding. There's nothing to do.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 4 are diagrams showing a first embodiment of the method for manufacturing a container with a metal lid according to the present invention.

As shown in FIG. 3, the container 10 with a metal lid has a front coat 21
and the peripheral edge 1 of the metal lid 11 coated with the back coat 22
2 is wound around the flange portion 15 of the plastic container body 14.

Next, a method for manufacturing such a container with a metal lid will be described in detail.

First, as shown in FIG. 1, an aluminum metal plate sheet having a thickness of 0.25+n+s is press-molded to create a metal lid 11 having a peripheral edge 12. Next, FIG. 4 shows an enlarged view of part A in FIG. 1. In FIG. 4, reference numeral 11a is the half-cut score of the easy open.

Subsequently, as shown in FIG. 2, a front coat 21 is applied to the surface of the metal Mll, and at the same time a back coat 22 is applied to the back surface of the metal lid 11. The surface coating layer may be formed before press molding.

As the surface coat 21, for example, an epoxy acrylic layer having a thickness of 0.03+o+s is used. Further, as the back coat 22, for example, a laminate of a corrosion-resistant layer 22a1 made of epoxy phenol with a thickness of 0.05 mm and a thermofusible resin layer 22b made of modified polyolefin with a thickness of 0.051 mm is used.

In other words, the layer structure in Figure 1 is as follows: becomes.

Among these layer structures, epoxy acrylic improves the glossiness and corrosion resistance of the metal M11. Furthermore, the epoxyphenol improves corrosion resistance, and the modified polyolefin has a heat-melting rejuvenation function.

Next, the metal tiEl, which has a front coat 21 applied to its surface and a back coat 22 applied to its back side, is coated with the contents 16 in advance.
The flange portion 15 of the container body 14 and the peripheral edge portion 12 of the metal lid 11 are overlapped with each other and are attached to the plastic container body 14 in which the container body 14 is housed.

Then, as shown in FIG. 3, the peripheral edge 12 of the metal lid 11 is wound around the flange 15 of the container body 14.

Plastic container body 1 used in this example
4 does not need to be particularly limited, as long as it has sufficient hardness and strength to withstand seaming, and laminated materials mainly made of olefin resin or polypropylene can be used.

Subsequently, the flange portion 15 of the container body 14 and the metal Yi 11
The tightening point with the peripheral edge part 12 of the metal Mll is heated, and the hot-melt resin layer 22b applied to the back surface of the metal Mll is melted, so that the flange part 15 of the container body 14 and the peripheral edge part 12 of the metal M11 are heated.
and are fused together.

According to this example, metal! ! 11 by press molding, a front coat 21 is applied to the surface of the metal lid, and a back coat 22 is applied to the back surface, so these front coats 2
1 and the back coat 22 due to press molding. For this reason, after press forming, the metal lid 1
There is no need to further apply a repair coat on the back coat 22 of No. 1.

Next, a second embodiment of the method for manufacturing a container with a metal lid according to the present invention will be described with reference to FIG.

In the second embodiment, a heat sealing member 23 is provided on the inner surface of the peripheral portion 12 after applying a front coat 21 to the surface of the press-formed metal M11 in the first embodiment and applying a back coat 22 to the back surface. This embodiment has additional operations, and the rest is the same as the first embodiment.

As this heat sealing member 23, modified polyolefin resin, ionomer resin, ethylene/acrylic acid copolymer, etc. can be considered.

According to this embodiment, when the seaming portion between the flange portion 15 of the container body 14 and the peripheral edge portion 12 of the metal lid 11 is heated,
Since the heat-melting resin layer 22b of the back coat 22 melts and the heat sealing member 23 also melts, the flange portion 15 of the container body 14 and the peripheral edge portion 12 of the metal lid 11 can be more completely fused.

In each of the above embodiments, an example was shown in which a laminate of the corrosion-resistant layer 22a and the heat-melt resin layer 22b was used as the back coat 22, but the invention is not limited to this, and only the heat-melt resin layer 22b made of modified polyolefin may be used. You may also use

In this case, the layer structure of the metal lid 11 is as follows.

Further, as the back coat 22, only the corrosion-resistant layer 22a made of epoxy phenol may be used.

In this case, the layer structure of the metal lid 11 is as follows.

Further, although an example is shown in which epoxy acrylic is used as the surface coat 21, the present invention is not limited to this, and a colored layer obtained by baking a coating liquid containing pigments and dyes may also be used. Alternatively, as the surface coat 21, a printed layer obtained by printing with metal ink may be used.

In this way, by using a colored layer or a printed layer as the front coat 21, the appearance of the metal lid 11 can be improved.

〔Effect of the invention〕

As explained above, according to the present invention, cracks do not occur in the anti-corrosion layer or the hot melt resin layer applied to the back surface of the metal lid. Therefore, since there is no need to further apply a repair coat after press molding, it is possible to reduce manufacturing time and manufacturing cost.

[Brief explanation of the drawing]

1 to 3 are diagrams showing a first embodiment of the method for manufacturing a container with a metal lid according to the present invention. The figure shows how the front and back coats are applied to the front and back sides of the metal lid, respectively. Figure 3 shows how the peripheral edge of the metal lid is tightened around the flange of the container body. 1st
It is an enlarged view of part A in the figure, and FIG. 5 is a diagram showing a second embodiment of the present invention. 10...Container with metal lid, 11...Metal lid, 12...
- Peripheral part, 14... Container body, 15... Flange part, 16... Contents, 21... Surface coat, 22...
Back coat, 22a...corrosion-proof layer, 22b...thermofusible resin layer. Figure 1 Figure 3

Claims (1)

[Claims] A metal lid is created by press-molding a metal plate sheet, and then at least one layer of a corrosion-resistant layer or a heat-melting resin layer is applied to the back side of the metal lid, and this metal lid is used as a plastic container containing the contents. A method for manufacturing a container with a metal lid, which comprises wrapping the container around the body.