JPH01279045A - Can container - Google Patents

Abstract

PURPOSE:To improve the shape retention and strength of a container body, by bonding together the tops, flanges, rib edges and bottoms of an inner and outer container body with ribs formed thereon. CONSTITUTION:An inner container body 2 and an outer container body 3 are formed separately. The inner container body 2 having a plurality of wrinkles 6 at each corner thereof is formed by stamping a multiple layer film into a circular form which is set between metal dies, each of which has its own grooves, and by sliding the same in an internal metal die 11 under pressure. The outer container body 3 can be formed by injection molding thermoplastic resin and is provided with ribs 5 on the inner surface of the sidewalls and bottom thereof. The preformed inner container body 2 is then placed in the outer container body 3 and bonded together at predetermined locations by, for example, heat sealing the required locations with a heat pressing jig pressed against the inner surface of the inner container body 2. Preferably, the inner container body 2 of a container body 1 consists of at least three layers with a metal foil interposed between two heat sealable resins.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to can containers, and in particular, can containers made mainly of synthetic resin.
The present invention relates to a container body of a can container 2 that can be used as a can container, a beverage can, etc.

[Prior Art] In the above-mentioned can VJ device, a container using a multilayer film having an aluminum (Δβ) foil as an intermediate layer and plastic layers on both sides, instead of a metal can, has been proposed.

However, these containers do not have the rigidity of a container, so methods such as injection molding a thick, rigid synthetic resin layer on the outer surface, or adhering a separately molded synthetic resin layer in the form of a reinforcing tray are required. In this case, the container body consists of an inner container body and an outer container body that is in full contact with the inner container body. Since it is used to mold a certain container,
In order to transform from two-dimensional to three-dimensional, it is necessary to perform some kind of processing.

The same applicant of the present invention previously proposed molding the above container using a female mold 11 as shown in FIG. 9 and a male mold 12 as shown in FIG. 1986-
90130 and 60-90131).

The outline of the method is as follows, for example.

That is, a multilayer film is punched out to a suitable size and placed on the upper surface of a female mold 11 having a groove 13 as shown in FIG.

After placing the multilayer film on the upper surface 19 of the female mold 11,
When the male mold 12 shown in FIG. 1O is placed on the multilayer film and pressed, the male mold 12 slides within the groove 13 of the female mold 11.

A part of the corner corner of these female mold 11 and male mold 12 + 6
...-117... Since a clearance is created in between, the remainder of the multilayer base H is collected at a part of the corner and folding is performed,
At the same time, the storage portion of the container body is formed.

FIG. 11 shows a perspective view of the container inner body 2 thus formed.

This container inner body does not involve cutting the film to an appropriate size, folding it, or connecting them using adhesive, as in the past, so the cut surface does not come into contact with the contents of the can, so it is food hygienic. Preferably, the retort characteristics can also be improved by sealing the lid.

That is, the container inner body 2 can be used as a container as is.
Using one of the plastic layers formed on both sides of the β foil, a lid 21 as shown in FIG. 11(A) is attached to the top of the inner container body 2 shown in FIG. 11(B) by thermal bonding. It can be attached to form a tight container, which has good retortability, excellent gas barrier properties, and can withstand long-term storage.

On the other hand, as a single-can container, it prevents the container from being deformed and crushed during transportation and work (such as stacking containers), and from being destroyed by lightning, and also improves the container's shelf life (gas barrier properties, airtightness), and In order to provide a more practical function as a can container, an outer container body (tray) 3 as shown in FIG. 11(C) can be attached to the inner container body 2.

Furthermore, for the same purpose, a resin layer may be formed by injection molding on the outer surface of the container inner body 2 having wrinkles 6 over the entire circumference as shown in FIG. 6(c).

In this method, as shown in FIG. 6(D), the container inner body (container) 2 is attached to the male mold part of the injection mold 22, and the mold 24 having the gate 23 is attached to the male mold part of the injection mold 22 as shown in FIG. )
The mold is clamped as shown in , and the thermoplastic resin 25 is injected from the gate 23 of the mold 24 to form a container body 26 in which the resin layer 25 made of the injected resin and the opposing surfaces of the container 2 are welded over the entire surface. obtain.

FIG. 7 shows an external view of the container body (in the case of a round can container) 26, and FIG. 8 shows an external view of the container main body 27 in a horn container.

[Issues to be Solved by the Invention]However, as mentioned above, in the case of the container body 26, 27, the outer body for the container must be made considerably thick in order to prevent deformation and destruction during lightning strikes. Must not be too thick.
Providing ribs on the outer surface of the container outer body makes it difficult to print on the surface, and providing ribs on the inner surface of the container requires a separate process, both of which are undesirable. -Inner body for containers with
The purpose of the present invention is to provide a new container in which a container outer body is combined which effectively contributes to shape retention and breakage resistance.

Further, other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for Solving Notification '3] In order to solve these objects, the present inventor conducted theoretical research and found that ribs were provided on the inner surface of the outer body of the container, and the inner surface of the container with gas barrier properties was created. They discovered that the problem could be solved by attaching the body to the outer body, and completed the present invention. That is, the gist of the present invention is to provide a body and an upper end of the body inside an outer body for a thermoplastic resin container, which has a body and a bottom, the body or the upper end thereof having a flange. In a can container having an inner container body with gas barrier properties, which has a flange and a bottom, the inner wall surface of the body part and the inner wall surface of the bottom part of the outer container body are coated with a desired surface. The outer surface of the flange of the inner body for containers is joined to the upper end of the body without the flange of the outer body for containers, and the outer surface of the bottom of the inner body for containers is at least partially joined to the bottom inner surface of the container outer body;
These can containers are characterized in that each edge of the rib on the outer body for the container is in contact with the outer surface of the inner body for the container, and each edge of the rib on the inner wall surface of the body of the outer body for the container is The above-mentioned can container is characterized in that it is joined to the outer surface of the body of the container inner body, and further, when the container outer body has an elliptical or rectangular planar shape, the inner wall surface of the bottom of the container outer body is The can container is characterized in that the ribs are provided parallel to the short axis in the case of an ellipse or the short side in the case of a rectangle.

A brief summary of the invention disclosed in this application is as follows.

That is, regarding the present invention, first of all, in terms of its manufacturing method, a gas barrier multilayer film is preformed to form the container inner body 2 having the wrinkles 6 in the same way as in the conventional method. A heating process is added to sufficiently smooth the inner and outer surfaces.

On the other hand, by injection molding, an outer body for a container having a body portion each having ribs on the inner surface and a flange portion at the upper end of the body portion of the bottom is molded, and the outer body for the container made of the thermoplastic resin (for example, polypropylene) is molded. The inner container body 2 is inserted into the container inner body 2, and the outer surface of the flange 2c of the container inner body 2 is joined to the flange or the upper end of the body of the container outer body, or the container is further attached to each edge of the inner container rib. The inner and outer surfaces of the body are fixed with heat adhesive. In this case, the bottom parts of the inner and outer bodies are thermally bonded, so that the integrity of the inner and outer bodies 1nl is improved.

As a result, structurally, the can container body of the present invention has a rib between the inner and outer bodies for the container.

[Function] In the present invention, as described above, ribs are inserted into the inner and outer bodies of the container, and the upper end of the body, the flange, the edge of the ribs, the bottom, etc. are bonded, so that the shape retention of the container body is reduced by 1 strength. Contributes to direction E.

Further, the accuracy of alignment between the inner container body and the outer container body is not so problematic as in conventional insert molding. Since these are manufactured separately and partially bonded together, the shape of the flange of the container outer body can be made arbitrary.

Furthermore, by providing a gap with the ribs, the gap acts as a buffer, which is important for can containers.
can improve sex.

Furthermore, the presence of voids can be advantageous in preventing thermal deformation, especially when the can container is an oval can or a horn (rectangular can).

[Example] Next, embodiments of the present invention will be described based on the drawings.

1A, 2, and 3 are cross-sectional views of the container body of a can container showing an embodiment of the present invention, and the container body 1
are exemplified by round can containers.

These container bodies 1 each include an inner container body 2 and an outer container body 3. The container outer body 3 shown in FIG.
It consists of a body part 3A, a collar part 3c bent at the upper end of the body part 3A substantially parallel to the bottom part 3B, and the bottom part 3B, and the center part of the bottom part 3B is a raised bottom part. Moreover, the inner container body 2 is composed of a body 2A, a flange 2C bent at the upper end of the body 2A substantially parallel to the bottom 2B, and a bottom 2B.

As shown in the figure, the container main body l shown in FIG. The outer surface of the bottom part 2B of the body 2 is joined to the inner surface of the circular rib 3B' of the bottom part 3B of the outer container body 3, and there is a gap between the outer surface of the inner container body 2 and the inner surface of the outer container body 3. A void 4 (reinforcing ribs not shown) is formed.

The container main body l shown in FIG. 3 is similar to that shown in FIG.
'' is erected, and the lower end of the body 2A of the container inner body 2 is joined to the upper end of the ring 3B''.

In FIG. 1A, ribs 5 for reinforcing the container outer body are provided on the inner surface of the container outer body 3 by utilizing the fact that the container inner body 2 and the container outer body 3 are separated as described above. The first
Figure B shows a sectional view taken along line A--A in Figure 1A.

As shown in FIG. 1B, a plurality of ribs 5 are provided on the inner peripheral surface of the container outer body 3 at appropriate intervals.

The rib 5 protrudes from the upper end of the flange 3C of the container outer body 3 to the lower edge of the body 3A at a desired height.

The ribs 5 are attached to the bottom 3B of the container outer body 3 as shown in FIG. 1A.
It may also be provided on the inner surface.

Although not shown, the ribs 5 may be provided only on the inner surface of the bottom portion 3B of the container outer body 3.

The flange 3C of the container outer body 3 shown in FIG. 1A suppresses outward protrusion compared to the flange 3C shown in FIGS. 2 and 3,
In addition, the same side surface 3C'' adjacent to the top surface 3G' of the flange is an inclined surface.

As shown in FIG. 1A, the outer surface of the flange 2C of the container inner body 2 is joined from the top surface 3C' to the side surface 3C'', and the body 2A and bottom al12B of the container inner body 2 are joined together.
The outer surface of the container 3 is joined to ribs 5 protruding from the inner surfaces of the body 3A and the bottom 3B of the container outer body 3.

As shown in FIG. 1B, a plurality of gaps 4 are formed between the outer surface of the inner container body 2 and the inner surface of the inner container body 3 at the portions not joined by the ribs 5.

FIG. 4 shows an embodiment in which the present invention is applied to a rectangular container.

As shown in FIG. 4(B), the rectangular container outer body 3 in this embodiment includes a part 1 from the top surface 3C' of the flange 3C on one long side 30 of the outer body 3, a body i3A and a A large number of ribs 5 for reinforcing the outer body are arranged in parallel to the short side 32 of the outer body, extending from the bottom 3B to the top surface 3C' of the flange 3C on the other long side 31, like the ribs of a ship. A plurality of ribs 5 are also protrudingly provided on both short sides 32 and 32 at appropriate intervals. Therefore, in the body 3A of the outer body 3, the rib 5 is provided along the rectangular body wall surface.

Inside this outer container body 3, a rectangular inner container body 2 having wrinkles 6 at the corners as shown in FIG. It is joined to the inner surface of the flange 3C of the outer body 3 as shown in FIG. Bonded to the end face (surface).

FIG. 4(C) is a cross-sectional view of the main part of FIG. 4(B) taken along the line B-B after the joining, and even if it is in the container body 1, the inner part is not joined to the rib 5. A gap 4 is created between the outer body 2 and the outer body 3.

Next, a method for manufacturing a can container according to the present invention will be explained.

This manufacturing method includes, for example, the following steps.

(+1 The inner container body 2 and the outer container body 3 are formed separately.

The inner body 2 is molded by the method described above, i.e.
As shown in Figure 6, the multilayer film is punched out into a disc shape,
The mold 11 has grooves 110° and 120°, respectively.
12, press it and slide it inside the female mold 11 to form the container inner body 2 having a large number of wrinkles 6 at the corners as shown in FIG. 6(c) and FIG. 4(a). obtain.

The container outer body 3 can be made by injection molding of thermoplastic resin. On each inner surface of the outer body 3S1 part and the bottom,
Ribs 5 are provided.

(2) Next, the preformed inner body 2 is placed inside the outer body 3 for a container, and bonded (adhered) at predetermined locations.
This joining can be carried out, for example, by pressing a heated pressing jig (not shown) along the inner surface of the inner body 2 against the inner cylinder 2 and heat-sealing the necessary locations.

(3) On the top surface of the container body 1, which is composed of the inner body 2 and the outer body 3 and has a gap 4, there is a lid 2 as shown in FIG.
1 can be installed.

The container inner body 2 of the container body 1 according to the present invention is composed of a multilayer base material of at least three layers, the intermediate layer being a metal foil layer and the both sides thereof having heat-meltable (thermally bondable) resin layers. is preferred.

The cross-sectional configuration of the multilayer base material is illustrated in FIG. 5.

In FIG. 5, 7 is a multilayer base material, 8 is an intermediate metal foil layer, and 9 and 1O are each a thermoplastic resin layer.

The multilayer base material 7 and the inner body 2 need to have gas barrier properties.

That is, even after putting food or drinking water for one can in the inner body 2 formed by the base material 7 such as oxygen and water, and putting the lid on, the can container can be retort sterilized by steaming. It is necessary to have so-called gas barrier properties that prevent gaseous substances that may have an adverse effect on the contents of the can from penetrating or emitting odors from the contents.

Multilayer base! ;! 7 can maintain the gas barrier property due to the metal foil 8 in the middle thereof, and can be made into a can container that can be stored for a long period of time.

A typical example of the metal foil 8 is Aβ foil.

The thickness of the metal foil 8 may be less than 100 μm.

However, in the present invention, there is no need to go through a stretching process when forming the inner body 2, so the thickness of the multilayer base material, especially the metal foil, is uniform, and a thin one can also be used, so this is mainly for economic reasons and ease of use. From the viewpoint of combustibility, the thickness is preferably 50μ or less.

Resin layer 9 constituting multilayer base material 7. IO can be melted by heat, and the resin layer 9 can be bonded to the thermoplastic resin constituting the outer body 3 by heat, and the resin layer! 0, it is necessary that it can be thermally bonded to the lid attached to the top surface of the container body l.

Various resins can be used for forming these resin layers 9 and 10, but the resin should have excellent heat resistance, oil resistance, and heat sealability required for retort sterilization at high temperature and high pressure, and Examples include polyolefin-based synthetic resins such as polyethylene, polypropylene, and ethylene-propylene copolymers, which do not cause migration of plasticizers, stabilizers, etc. from the resin into the contents of cans such as foods.

The resin layer 9. The thickness of lO is 40μ or more, preferably 5
0 to 100μ is appropriate.

Examples of the thermoplastic resin constituting the container outer body 3 include polyolefin synthetic resins such as polypropylene resin. The ribs 5 may also be made of a similar thermoplastic resin and may be constructed integrally.

It is preferable to mix an inorganic filler with the thermoplastic resin. Mixing the inorganic filler has the following advantages.

■The dimensional stability of the container outer body is improved and the shrinkage rate is reduced, which is advantageous.

■ Improved heat resistance and increased heat distortion temperature, which is advantageous for retorting.

■The amount of calories burned during waste incineration is low and does not damage combustion furnaces.

■It can provide rigidity, which is advantageous in terms of product distribution.

■Good heat conduction, which is advantageous for retorting.

■Costs can be reduced.

Examples of inorganic fillers include aluminum oxide, calcium carbonate, and silica.

[Effects of the Invention] (1) The inner body constituting the can container of the present invention is obtained by setting a multilayer base material between male and female molds, sliding the multilayer base material into the hollow part of one of the molds, Unlike conventional drawing processing, the flat multilayer base material is made into a three-dimensional inner body without being stretched substantially, so it is possible to create a multilayer with a metal foil such as Aβ foil that is extremely thin, for example less than 40 μm. It was possible to provide a container body having an inner body made of a plastic base material.

This ensures gas barrier properties, allows the metal foil, which accounts for a large amount of weight when using a multilayer base material, to be regulated to the minimum thickness for the required level of barrier properties, and reduces manufacturing costs. I was able to do that. Furthermore, since thin AQ foil can be used, complete combustion is possible.

(2) As mentioned above, when creating a three-dimensional inner body from a flat multilayer base material, there is inevitably a surplus, but in the present invention, this can be absorbed as wrinkles or folds. can do.

(3) According to the present invention, by attaching an outer body made of thermoplastic resin to the inner body, it is possible to make use of the characteristics of the inner body having the above-mentioned characteristics and provide a more practical function as a can container; It was possible to prevent deformation and crushing during transportation and work as a can container, and further improve the storage stability (gas barrier properties, sealing performance) as a can container.

(4) In addition, when installing the above-mentioned outer body, instead of making the inner body and outer body stick together on the entire surface as in the past and making them integral (instead of installing ribs between the inner body and the outer body, Printing on the outer surface of the container body is also easy.

(5) In the present invention, the inner body and the outer body are not entirely joined but are partially joined, and a gap is provided between the inner body and the outer body.In addition to the above-mentioned advantages, the presence of the gap also provides the following advantages:
It had a cushioning effect and was able to improve the drop-drop resistance, which is an important matter for can containers. In addition, heat conduction was improved, which was advantageous for retorting.

Furthermore, due to the presence of the void, ribs for reinforcing the outer body can be provided on the inner surface of the outer body, and by providing the ribs, when the inner body with the above characteristics is disposed inside the outer body, The shape retention of the inner body could be further improved.

Such ribs are particularly advantageous in the case of horns and ovalizations, which are prone to deformation and collapse.

(6) According to the present invention, since the inner container body and the outer container body are molded separately and then joined and molded, the shape of the flange of the outer body can be made into any desired shape, as shown in FIG. 1A. In the case of the shape shown in FIG. 1A, it is difficult to release the gas by conventional integral molding by injection molding.

(7) Since the container body of the present invention has polyolefin synthetic resin on its outer surface, heat sealing is good, and a lid made of an appropriate material can be easily attached by heat sealing, etc., and it can be made into a tight container. It can be used in a wide range of applications, such as can-like containers that can be retorted, have good gas barrier properties, and can withstand long-term storage, such as canned containers, soup containers, and various beverage cans.

(8) According to the present invention, since the surface of the multilayer base material of the inner body is a resin layer, it is possible to provide a can-like container body that eliminates the disadvantages of metal cans such as deterioration in the taste of food. Furthermore, the outer body can be made more fashionable by selecting various resins and designs.

[Brief explanation of the drawing]

FIG. 1A is a cross-sectional view showing an embodiment of the present invention, FIG. 1B is a cross-sectional view taken along line A-A in FIG. 1A, FIG. 2 is a cross-sectional view showing another embodiment of the present invention, and FIG. FIG. 4(A) to FIG. 4(B) are perspective views showing embodiments of the present invention, and FIG. 4(C) is a sectional view showing still another embodiment of the present invention. FIG. 5 is a cross-sectional view of the structure of a multilayer base material showing an embodiment of the present invention, and FIGS.
(C) is an explanatory diagram of the molding process of the inner body for a container used in the present invention, FIGS. 6 (E) to (F) are explanatory diagrams of the conventional process, respectively, and FIGS. A perspective view showing an example, FIGS. 9 and 10 are perspective views of a mold used in the preform process, FIG. 1+ is a perspective view of an inner body for a container used in the present invention, and FIG. A) is a perspective view of the lid body, FIG. 12(B) is a perspective view of the inner body for the container, and FIG.
FIG. 2(c) is a perspective view of the outer body for a container. l... Container body 2... Inner body for container 2A... Body part 2B... Bottom part 2C... Flam part 3... Outer body for container 3A... Body part: 313...・Bottom part 3C...Brim part 4...Gap

Claims (1)

[Scope of Claims] 1. A body and an upper end of the body are placed inside an outer body for a thermoplastic resin container, which has a body with a flange on the body or its upper end, and a bottom. In a can container having an inner container body with gas barrier properties, which has a flange and a bottom, the inner wall surface of the body and the inner wall surface of the bottom of the outer container are coated with a desired surface. The outer surface of the flange of the inner body for containers is joined to the flange of the outer body for containers or the upper end of the body without the flange, and the outer surface of the bottom of the inner body for containers is is at least partially joined to the bottom inner surface of the container outer body,
A can container characterized in that each edge of the ribs of the outer container body is in contact with the outer surface of the inner container body. 2. The can container according to claim 1, wherein each edge of the rib on the inner wall surface of the body of the outer body for a container is joined to the outer surface of the body of the inner body for a container. 3. When the container outer body has an elliptical or rectangular planar shape, the ribs on the inner wall surface of the bottom of the container outer body are
The can container according to claim 1 or 2, wherein the can container is provided parallel to the short axis in the case of an ellipse or the short side in the case of a rectangle.