JPS59103840A - Vessel made of metal with circumferential joining section - 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] The present invention relates to a metal container having a circumferential joint.

A metal container having a circumferential joint manufactured by fitting the open ends of two metal cup-shaped molded bodies having approximately equal diameters and relatively thin walls to each other via a film adhesive and joining the two. was proposed.

In such a metal container, in order to prevent the corrosion of the inner opening edge that does not have a protective coating or the metal leaching from this edge into the contents, a predetermined length of film adhesive is applied, for example. It is preferable to adhere the film adhesive to the outer periphery of the opening end, and then fold it back and adhere so that the film-like adhesive wraps the edge of the inner opening end and the subsequent inner peripheral surface.

Under the above circumstances, regarding this folded part, the circumferential length of the inner wall of the opening end σ is made to accurately match the length of the film adhesive, and the ends of the film adhesive are aligned. It is conceivable to glue them together with the two butted against each other. However, it is difficult to completely bond the adhesive to each other at these abutted parts, so during various processing steps or when opening the can, the edges of the film adhesive are There is a danger that the two may separate and cause damage. If the ends are separated, the edge of the open end without the protective coating will be exposed.

If such an exposed metal part exists inside the container, when the contents are filled and stored, metals will be leached into the contents, which will severely impair the taste and flavor. Further, metal corrosion under the protective coating layer tends to gradually spread starting from this exposed metal portion, resulting in a decrease in sustained adhesive strength and a significant weakening of the strength of the joint. If the corrosion is severe, leakage will occur from that area.

There are problems such as damage and holes.

The present invention has been made in view of the above situation.

The purpose of the present invention is to ensure that the film adhesive adheres to the entire circumference of the inner open end, thereby providing corrosion resistance and
An object of the present invention is to provide a metal container having a circumferential joint in which sealing performance and joint strength are significantly improved.

According to the present invention, an upper body and a lower body are each made of a metal cup-shaped molded body, and the upper body and the lower body are overlapped and joined together at their circumferential open ends via a film adhesive. In a metal container that is
A bonded metal container characterized in that the film adhesive is bonded to the edge of the inner open end of the overlapped joint and to the inner circumferential surface following this, with an overlapping portion in the circumferential direction. is provided.

Next, a metal container according to the present invention will be explained with reference to the accompanying drawings FIGS. 1 to 3.

This metal container 10 includes a lower body 12 and a lower body 14. These cup-shaped upper body 12 and lower body 14 are made of, for example, a light metal plate such as aluminum or ram, or an untreated steel plate (
black plate), various surface-treated steel sheets such as pan-plated steel sheets (tinplate), galvanized steel sheets, aluminized steel sheets, chrome-plated steel sheets, etc.; electrolytic treated steel sheets such as electrolytic chromic acid treated steel sheets; phosphoric acid and/or It is formed by drawing, drawing and ironing a chemically treated steel plate such as a chromic acid treated steel plate. In the case of drawing, the thickness of the metal material to be processed varies depending on the final dimensions of the container and the grade of the material, but generally it is 0.1 to 0.5 mm, particularly 0.2 to 0.35 mm. In the case of ironing, the thickness of the 41Q wall is preferably in the range of 0.05 to 0:3, particularly 0.06 to 0.20 tratr. 1st
The shapes of the upper body 12 and the lower body 14 shown in the figures are merely examples; for example, the height of the lower body 14 can be made high, and the height of the upper body can be made low to give it a flat shape. .

On the inner surfaces of the upper body 12 and the lower body 14, a protective layer, which is an anticorrosion coating film that preferably has excellent thermal adhesion with the film adhesive 16, is formed. A single layer of primer having excellent thermal adhesion to the film adhesive 16 is formed on the outer circumferential surface of 2o, if necessary.

The paints forming these protective layers and the primer layer include any paints made of thermosetting and thermoplastic resins; modified epoxy paints such as phenol-epoxy paints and amino-epoxy paints; beer chloride-vinyl acetate paints, etc. Vinyl or modified vinyl paints such as polymers, partially saponified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate, maleic anhydride copolymers, epoxy-modified-epoxyamino-modified-or epoxyphenol-modified-vinyl resin paints; Acrylic resin paints; synthetic rubber paints such as styrene-butadiene co-'TJ1 combination, etc. are used.

The inner diameter of the open end 18 of the upper body 12 and the outer diameter of the open end 20 of the lower body 14 are dimensioned to be approximately equal in size. If the thickness of the film adhesive is t, then the tightening margin S is expressed as follows.

S=(1)2+2t), DI open end 18
The mutual pressure acting on the fitting portions of and 20 is proportional to the size of this interference S. The inner diameter 5, outer diameter D2, and thickness t are selected so that appropriate mutual pressure is always applied.

The film adhesive 16 should have a softening point (melting point) of 100 to 240°C, especially 120 to 240°C, from the viewpoint of thermal adhesion and heat resistance, and should have a softening point (melting point) of 120 to 240°C, and has good flowability, wettability with materials, and adhesion. From the viewpoint of strength, etc., it is desirable that the adhesive has a melt viscosity of 1000 to 500,000 voids at a temperature 30°C higher than the softening point (melting point). However, the adhesive is reliably fused due to the pressure applied during pasting or folding, and the adhesive melts appropriately during bonding, allowing the fusion of the adhesives and the adhesion between the adhesive and the protective layer to occur completely. It will be done. Furthermore, in terms of the workability of coating the inner open end, the coating workability at 20°C is 0.
It is desirable to have a relatively low flexural modulus of 05X10' to 3X10'Kq/Cm2. The film adhesive is made of a thermoplastic resin capable of forming a film, and from the viewpoint of adhesion to edge metals, primers, etc., it is desirable to have a certain amount of polar groups in the main chain or side chains. ×× From this standpoint, carbonyl groups (-C-) are based on carboxylic acids, carboxylates, carboxylic anhydrides, carboxylic esters, carboxylic acid amides, ketones, carbonic esters, urea, urethane, etc. as thermoplastic resins. It is desirable to use a thermoplastic 1 polymer containing as its main component in the main chain or side chain. Resins that can be used in the process of the invention are, in order of importance, polyesters, polyamides, ionomers, acid-modified polyolefins, and polycarbonates.

These resins should have at least a sufficient molecular weight to be able to form a film, and if desired, these resins may be supplemented with compounding agents known per se, such as Shiyu (line absorbers,
Stabilizers, lubricants, antioxidants, fillers, pigments, dyes, antistatic agents, and the like can be blended according to known formulations.

The metal container according to the present invention is manufactured, for example, as follows.

First, a film adhesive 16 is attached to the outer periphery of the open end 20 of the lower body 14 formed in the above-mentioned hole. This film-like adhesive 16 can be obtained by cutting a tape-like material, or it can also be obtained by forming a film from a resin extruded from an extruder. The thickness of the film adhesive 16 is preferably between 0.01 and 0.3 mm, particularly preferably between 0.02 and 0.15 mm. The length of the film adhesive 16 is longer than the circumference of the open end 20 of the lower body 14, so that when the film adhesive 16 is attached to the open end 18, the film adhesive 1
6 will partially overlap. The film adhesive 16 is attached to the open end 20 so that a protruding portion is formed in the width direction (that is, the vertical direction in FIG. 1). That is, the lower part of the film adhesive 16 in the width direction is stuck to the open end 20, but the upper part is stuck to the open end 20.
It extends further beyond the uppermost edge 30 of o to form an overhang.

As shown in FIG.
It is bent inward so as to wrap around the edge 30 of 0 and the inner circumferential surface that follows it, folded back, and fused thereto.

Thereafter, the lower body 14 is fitted with the open end 18 of the upper body 12 so that the open end 20 of the lower body 14 is on the inside. Then, heat the fitting part with the two while applying mutual pressure,
The adhesive present in the fitting portion is melted, cooled and solidified to join both members. The joint can be heated by high frequency induction heating, infrared heating, hot air heating, etc., and cooling can be done by any operation such as natural cooling, air cooling, water cooling, etc.

- In the above folding process, a uniform force is applied from the inside to the outside to press the film adhesive 16 against the open end 20 of the lower body 14 in a heated state.

For example, FIG. 2 is a vertical cross-sectional view of the joint portion of the metal container 10 according to the present invention manufactured in this manner, and FIG. 3 is a cross-sectional view of the joint portion.
Shown in the figure.

In this metal container 10, the open end 1 of the upper body 12
8 and the open end 20 of the lower body 14 is compressed by the open ends 18 and 20 and heated during the bonding process, so that a film-like adhesive is formed. The thickness of the double layered portion of the agent 16 is approximately equal to the thickness of the other portions. On the other hand, in the inwardly folded portion, the thickness of the doubled overlapping portion 24 is thicker than the other portions.

The outer and inner walls of the open ends 18 and 20 of the pass-through shown in FIG. 2 are provided with the above-described pass-through protective layer or primer 1-26. However, when the cylindrical open ends of the cups are overlapped and joined together, the free edge of the metal material is inevitably exposed inside the joint.

In the metal container according to the present invention, a film adhesive 16 is bonded to the edge 30 of the inner open end 20 and the inner circumferential surface following the edge 30 with a circumferential self-overlapping portion 24. The length of this overlapping seam portion 24 is preferably between 0.1 and 10 mm, particularly between 0.5 and 5 mm, in consideration of the reliability and economy of adhesion between the film adhesives. Something is good. By providing this overlapping portion 24, the end faces of the film adhesive will not separate during various processing steps or during use of the can.
The edge 3o of the open end portion 20 that does not have a bulge is not exposed. Further, the weight portion 24 is heated while being subjected to pressing forces from the inside and outside during the folding process, for example. Therefore, in the overlapping portion 24, the adhesive film 16 is firmly bonded to itself and the free primer layer 26 and the adhesive film 16 are firmly bonded. Since the overlapping seam portion 24 has a greater thickness than the other portions, the pressing force acts particularly strongly, and the bonding is performed with a bonding force at least equal to that of the other portions.

Therefore, the container according to the present invention can be particularly suitably used as a container for accommodating corrosive contents, and further as a container for accommodating contents having autogenous pressure such as carbonated drinks, beer, and low-malt beer.

Next, examples will be described.

In each of the Examples, the content filling and storage test was carried out after storage at 37° C. for 6 months, and the following evaluation was performed for each test item. The amount of metal elution (iron, aluminum), flavor, discoloration, inner surface condition of the container, and deformation strength were all tested using 10 test containers.

Amount of metal eluted: Ratio of eluted metal amount (my) to content io1"joy (ppm) Flavor -: Results of flavor test conducted by 10 people 5: Excellent, 4: Good, 3: Average 2 : Poor, 1: Poor discoloration Color: Change in the color of the contents Container inner surface condition: Visual evaluation of the inner surface joints of the container after the can is opened (state of rust, changes in paint film, etc.) Deformation Strength: Contents An iron rope with a tip radius of 10 mm and a weight of 4 kg was dropped from a height of 30 rrrM onto the joint of a container filled with water. After applying modified vinyl paint to the inner and outer surfaces of rrvn's tin-plated steel plate and baking it, 94rr
An upper body with a spout provided on the upper wall was produced by punching out a circular plate with a diameter of 64 mm and press-forming using a conventional method (inner diameter of the upper body is 64 mm).
12 cities).

On the other hand, a tin-plated steel plate with a material thickness of 0.30 tan was punched into a disc with a diameter of 120 mm, and then formed into a cup shape with an inner diameter of 85 mm using a conventional press forming method. Next, this cup-shaped molded product was subjected to reproofing, and then ironed using an ironing punch with a diameter of 66.1 mm and an ironing die. After degreasing and cleaning the inner and outer surfaces, a conventional surface treatment (cynic acid system) was carried out, and a modified vinyl paint was applied and baked on the inner and outer surfaces. Next, neck-in processing is performed, and the neck-in outer diameter is 64.11 m.
A lower body with a neck implant length of 4.5 m was prepared.

Apply a film adhesive to the outer periphery of the open end (neck-in part) of this lower body as shown below, so that the 9 overlapping parts of the periphery are 2.5
It was attached so that the distance was ~3.0. Suwachi, width 6mm
5 A modified polyester film adhesive (softening point 180°C) with a film thickness of 80 μm was cut to a length of 205 mm, and was placed so as to locally surround the outer periphery of the open end of the lower body. Due to the high frequency heating coil, the temperature of the application site is 210℃.
The film adhesive was applied to the outer periphery of the open end of the lower body by heating to ~230°C. At this time, the length of the overlapping portion of the adhesive in the circumferential direction was 2 to 3 mm, and the length of protrusion from the open end was 1.5 rrnn.

Next, the protruding part of the film-like adhesive stuck to the open end was bent radially inward using a bending tool (having a guide hole with an inner diameter of 64.27 m and a circumferential step of <0.20 mm). Then bend the core into a 1mm surface (outer diameter 64mm).
．． 10mm) is inserted into the outer periphery of the open end, folded back inward in the axial direction, and heated to 190 to 210°C on the entire circumference by a high-frequency heating coil embedded inside the tool, forming a film on the inner wall of the open end. Fuse the adhesive.

The diameter of the open end of the lower body coated with the film-like adhesive thus obtained was reduced, and the open end of the lower body was fitted to the open end of the lower body so that the open end of the lower body was on the inside. Next, while applying mutual pressure to the mating part, the high-frequency heating coil disposed around the outer periphery of the mating part heats the mating part to a temperature in the range of 200 to 215°C without rotating the mating body. After heating to melt the adhesive, the adhesive was cooled and solidified to produce a metal container with a capacity of about 509 ml in which the upper body and the lower body were joined.

When I cut out the joint of this container and examined the inside surface, I found that
The film adhesive was completely adhered to the inner coating film around the entire circumference. The film adhesive had two to three overlapping edges, and the adhesives in the overlapping areas were also completely fused together.

Cola, beer, and synthetic carbonated beverages were cold-filled into the container thus obtained, and the spout was tightly plugged. These containers were subjected to heat killing treatment under the conditions shown in Table 1.

Table 1 During processing, no leakage was observed at the circumferential joint [f1].

Pack these bamboo containers into cartons (10 cases, 24 cans/
After storage at 37℃ for 6 months, the iron elution amount, flavor, discoloration, inner surface shape of the container, and deformation strength were determined by Mi, Tl.
Beta. The results are shown in Table 2.

From the results in Table 2, it can be seen that the container of the present invention has a perfect surface resistance at the inner end of the joint, so there is little metal leaching into the contents, excellent resistance to contents, and no corrosion occurs. No good,
It became clear that the container had excellent sealing properties and bonding strength.

Comparative Example 1 An upper body and a lower body were produced in the same manner as in Example 1. A modified polyester film adhesive with a width of 6 mm and a film thickness of 80 μm (softening point: 180°C) is applied to the outer periphery of the neck-in portion of this lower body.
was set to a length of 201.3 mm, cut, and adhered in the same manner as in Example 1 so that the film-like adhesives were butted without overlapping in the circumferential direction. At this time, the protruding length from the open end was 1.5 tra+.

Next, the IT protruding portion of this film adhesive was fused to the inner wall of the open end in the same manner as in Example 1.

After fitting the upper body and lower body obtained in this way, heating 1
A metal container with a capacity of about 5Q□+++/ was prepared by combining 55 pieces.

When we cut out the joint of this container and examined the inner surface, we found that
The circumferential ends of the film adhesive are not completely fused together, or the ends are separated, resulting in an open end i+M.
There were many things that were not completely detailed.

Cola, beer, and synthetic carbonated drinks were packed in the container thus obtained in the same manner as in Example 1. Some leakage was observed from the joints immediately after the pack.

Pack these containers into cartons (10 cases, 24 cases)
)k/case), after storage at 37°C for 6 months,
Buko who makes the same evaluation as 1. The respective results are shown in Table 2.

From the results of No. 21.--, containers other than those of the present invention do not completely protect the inner edge of the joint, so there is a lot of metal leaching into the contents, poor resistance to contents, and corrosion. It was also revealed that the leakage was inferior.

Example 2 An organosol-based coating film was applied on both sides in advance to a thickness of 0.
23 mm aluminum alloy plate (3004 material, HI3
) was punched and drawn in a conventional manner to produce an upper body having an inner diameter of 121.90 m at the edge of the joint and a spout with a diameter of 38 mm in the center.

On the other hand, a lower body having an outer diameter of 121.90 mm at the joint end f was manufactured by punching and drawing the same painted plate.A polyamide adhesive ( Softening point: 185°C) was processed using an extrusion frame attached with a gear pump to reduce width to 7wn% thickness -x], n.

It was extruded into a .mu.m film and coated by rotating the lower body about once. At this time, the circumferential overlapping length of the adhesive was 2.5 to 3.0 rrrIn, and the protruding length from the open end was 1.5 mm.

Next, fold the protruding part of the film adhesive stuck to the open +i end in the same manner as in Example 1. Fold back using a rubber core (outer diameter 121.60 + ns), 190
The film adhesive was fused to the inner wall of the open end by heating to ~210°C.

In this way, a metal Jig container with a drawing room size of about 2 tons was produced by fitting and heating the lower body and the lower body obtained in [-]. Cut out the joint of this container and examine the inner surface. At around ζ7, the film adhesive was completely adhered to the inner coating over the entire circumference, and the film adhesive had an overlap of 2.5 to 30 mm. The adhesive at the anal area was also completely fused together.

After filling beer into the container filled with VCl, the spout was tightly closed and sterilized at 65° C. for 30 minutes.

No peeling p'H1 or leakage of the circumferential joint occurred during the treatment. Torera containers (2 each (10Pni) to 3
After storage for 6 months at 7℃, aluminum leaching, flavor,
Discoloration, inner surface condition of the container, and deformation strength were investigated. The respective results are shown in Table 3.

From the results in Table 3, the container of the present invention completely protects the inner edge of the joint, so there is little metal leaching into the contents, it has excellent resistance to contents, and there is no corrosion. It was revealed that the container also has excellent sealing properties and bonding strength.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a metal container with a circumferential joint according to the invention. FIG. 2f:j, - An enlarged longitudinal cross-sectional view of the joint of the Zennichi container of FIG. 3 is an enlarged cross-sectional view of the metal container joint taken along line AA' of FIG. 2; FIG. 10...Metal container 12...Upper body 14...Lower body 16...Film adhesive 20...Opening part 1 of lower body 14 24... -1Fr portion 30...・Edge of open end 20

Claims (1)

[Claims] 1. An upper body and a lower body each made of a metal cup-shaped molded body are provided, and the upper body and the lower body are connected to each other at their circumferential open ends via a film adhesive. In a metal container that is overlapped and joined, the film adhesive has a circumferentially overlapping seam on the edge of the inner open end of the overlapped joint and on the inner circumferential surface following this. A metal bonded container characterized by being bonded. 2. The metal container according to claim 1, wherein the length of the overlapping υ portion is 0.1 to 10rrrrrn. 3. The metal pot container according to claim 1, wherein the length of the overlapping portion is 0.5 to 5 mm.