JPH02127247A - Lid made of pressure-resistant plastic - Google Patents

Abstract

PURPOSE:To improve resistance against pressure inside a can by providing bars made of synthetic resin having cuts formed from a lower direction toward a rear of a bottom section in a grid shape on the rear of the bottom of a can- like container lid base. CONSTITUTION:On a rear of a bottom section of a can like container lid base, a bar 12 made of synthetic resin is adhered while an appropriate number of cuts 13 are provided on the bar 12. The cut 13 is provided from a lower direction toward the rear of the bottom face while its depth does not reach the bottom rear face but the lower cut 13 on a score part 3 is deeper than other cuts 13 from the viewpoint of openability to reach the vicinity of the bottom rear face. When pressure inside the can is applied, it functions toward a direction that intervals between the cuts 13 are closed so that resistance against pressure inside the can can be improved. On the other hand, with respect to a direction of opening the can from an upper direction, force functions in a direction that said intervals become wider so that it does not prevent openability. In addition, providing of the bar 12 improves strength of a lid 8.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a lid constituting a can-like container, and in particular, a lid that is made mainly of plastic by injection molding and has high pressure resistance and can-drop strength. , relates to a pressure-resistant plastic lid that is easy to open.

[Prior Art] Can-like containers filled with beer, carbonated drinks, etc. are subjected to high-temperature retort processing, so pressure inside the can is applied to the lid and the like. When using plastic cans instead of conventional metal cans, in addition to issues such as moldability, food hygiene, and retort characteristics, resistance to pressure inside the can is also an important issue. In addition, the strength of cans when dropped is also an issue, especially when the can is dropped, the impact is often applied to the lid.Furthermore, with beer cans and beverage cans such as those mentioned above, when the lid is opened and the contents are Therefore, it is important to consider how easy it is to create an opening that can be opened easily.

The present inventors previously proposed the following regarding the plastic lid. An example of this will be explained based on the drawings. FIG. 4 is a plan view of the lid, and FIG. 5 is a sectional view taken along the line T-1 in FIG. 4.

As shown in FIG. 5, the lid includes a base material 1 for a can-like container lid, a synthetic resin 2, a score portion 3, and a tab 4.

In this example, the can-like container lid base material 1 has a three-layer structure, and the middle layer 5 is made of a so-called gas barrier base material that is impermeable to oxygen, water, etc. , made of aluminum (Aβ) foil. The can-like container lid base material 1 has a thermally bondable synthetic resin layer 6°7 on both sides of the Δβ7i5. Therefore, the can-like container base material 1 is made of a gas barrier multilayer base,
Its surface layer has a synthetic resin layer 6 that can be thermally bonded to the body of the can-like container, as will be described in detail later.

In addition, as shown in the figure, the can-like container swallow base material 1 includes a bottom part IA and a rising part I that is connected to the outer periphery of the bottom part IA.
B, and a flange portion IC projecting outward from the rising portion IB in parallel to the bottom portion IA.

The can-like container lid base material 1 has an intermediate layer 5 of, for example, 50
The synthetic resin layer 6.7 on both sides of the foil is formed to have a thickness of, for example, less than 100 μm, making the whole foil thin.

As shown in the figure, a synthetic resin layer 2 is laminated on the surface (outer surface) of the can-like container lid base material 1 opposite to the side on which the body of the can-like container is attached.

In the illustration, a synthetic resin layer 2 extends parallel to one part IB of the base material 1 from the edge of the flange IC of the base material 1 for a lid of a can-like container.
Although the flange portion IC is projected, the edge of the flange portion IC and the edge of the synthetic resin layer 2 may be aligned. In this case, when the end of the flange IC of the base material 1 is further extended parallel to the rising part IB and coincides with the edge of the synthetic resin 2, or as described above, There are cases where the edge of the flange IC of the base material 1 and the edge of the synthetic resin layer 2 are made to coincide without causing the resin layer 2 to protrude parallel to the rising portion IB.

In any case, in the lid 8, a synthetic resin layer 2 is laminated on a base material for a can-like container lid.

However, for the opening of the lid 8, it is necessary to install the score part 3 in the part that requires the opening, and the synthetic resin N2 is not laminated in the score part 3. That is, the surface of the thermally bondable synthetic resin layer 7 of the can-like container lid base material 1 is exposed to the outside.

In this example, the score section 3 is configured in a band-like track shape.

The score portion 3 is cut by a synthetic resin tab 4 attached to the upper surface of the synthetic resin layer 2, and thus the lid 8 is opened. FIG. 7 shows a plan view of the lid 8 after the corresponding period, and FIG. 8 shows a sectional view taken along the line 1-11 in FIG. When the rear end is held to one side as indicated by the arrow, the leading end presses the base material 1 for can-like container lids, and this is done by cutting the base material 1 at the score section 3. .

The method for forming the lid 8 can be carried out using an injection molding device, and an outline of the manufacturing method is as follows: A hair root-shaped can-like container lid base material 1 is installed in the device in advance, or Bottom I
The base material 1 on which A, the rising part IB, and the flange part IC are formed (preform molded) is installed in the apparatus in advance, and the synthetic resin forming the synthetic resin layer 2 is placed in the metal layer in the apparatus. This is done by injecting into the cavity after the mold is clamped. The tab 4 may be attached later to the upper surface of the synthetic resin layer (hereinafter referred to as the injection resin layer) 2 laminated by injection molding, but during the injection molding,
The process can be simplified by attaching the tab 4 in advance and attaching it at the same time. The score portion 3 can be formed by a method such as providing a convex portion in a mold during injection molding and preventing the injected resin layer 2 from reaching the convex portion.

As shown in FIG. 6, the lid 8 is attached to the body 9 by thermally bonding its peripheral edge. The body 9 is also constructed of a plastic body having a similar heat-bondable synthetic resin layer surface, and the body 9 is heated by melting the heat-bondable resin layer 7 of the can-like container lid base l. Join. In addition, in the 6th M, IO indicates the bottom cover.

11 constituted by the lid 8, the body 9, and the bottom lid 10;
The contents of the can such as beer, coffee, uron tea, cola, etc. are filled into the 7-type container 11.

FIG. 9 shows a perspective view of the lid 8 viewed from the back side.

[Problems to be Solved by the Invention] In the first container 8, a molten injection resin layer 2 is laminated on a resin layer 7 capable of heat-sealing 1iJ of the base material 1 for a lid of a 11-like container. Therefore, the adhesive strength is high, the can drop strength is high, the retort characteristics are good without peeling during retorting, the lid can be opened easily, and it maintains 61 pressure resistance to withstand the pressure inside the can. Due to the use of the thin-walled container base material 1, the lid 8 of the pressure-resistant can-like container may curve upward due to the pressure inside the can. Then, distortion may occur in the score section 3.

Therefore, the present invention provides the pressure-resistant PlusDeck lid,
The object of the present invention is to provide a technology that can improve resistance to internal pressure while not adversely affecting can drop strength and ease of opening.

Other objects and novel features of the present invention will become apparent from the entire description and drawings.

[Means for Solving the Problems] A brief summary of typical inventions disclosed in this application is as follows.

The present invention provides a lid as described in item 1, in which synthetic resin pillars having cuts formed from below toward the bottom back surface of a base material for a can-like container lid are attached in a grid pattern to the bottom back surface.

That is, as shown in FIG. 9, in the conventional example, the bottom IA back surface of the can-like container lid base material 1 constituting the lid 8 is a flat surface, but in the present invention, the bottom back surface is flat. A synthetic resin crosspiece with cuts was attached.

[Function] In this way, by attaching (adhering) the crosspieces, the thickness is partially increased over the entire bottom, which suppresses the bending of the bottom in two directions when F1 force is applied inside the can. 11-, and the machine is provided with a cut from the bottom to the back surface of the bottom, and the cut is closed in the direction of the pressure inside the can, so the pressure resistance against the pressure inside the can is improved by using white clay. can be done. On the other hand, the cut is made from the bottom, which is opposite to the downward can opening direction when lifting the rear end of the tab 4 and cutting the score part 3, as described above. It has the function of widening the interval between the cuts 1].

Therefore, by attaching a crosspiece having a cut to the back surface of the bottom, the resistance against the internal pressure of the can is increased, and the ease of opening is not adversely affected.

Furthermore, by installing this machine, it is possible to increase the strength of dropped cans and reduce the impact on the score section.

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

As shown in FIG.
A synthetic resin pillar 12 is attached to the back surface. The machine 12 is provided with an appropriate number of cuts 13. As shown in the figure, the cut 13 is provided from above to the back surface of the bottom IA. The depth of the cut 13 is such that it does not reach the bottom back surface, but from the viewpoint of easy opening, the lower cut 13 of the score part 3 is
It is preferable that the cut is deeper than the other cuts 13 and has a depth that reaches near the bottom back surface.

FIG. 2 shows a perspective view of the lid 8 according to the present invention, seen from the bottom side. The said FIG. 2 can be compared with the above-mentioned FIG. 9. The machine 12 is attached to the bottom back surface of the lid 8 in a grid pattern.

FIG. 3 is an enlarged explanatory view of part A in FIG. 2, in which two cuts 13 are provided in the crosspiece 12 in the horizontal direction in the drawing, at appropriate intervals in this embodiment. No cut 13 is provided in the crosspiece 12 in the vertical direction shown in the figure.

Intermediate layer 5 of gas barrier multilayer base material used in the present invention
Examples of the gas-barrier base material constituting the material include metal foils such as beta foils, as well as films and sheets of saponified edylene-vinyl acetate copolymers, polyvinylidene chloride, and the like.

The thickness of the intermediate layer 5 is preferably 50 μm or less, preferably 9 μm, in view of the ease of opening the lid and the drop strength of the product.
It is desirable that the thickness is ~30μ.

Examples of the synthetic resin constituting the injection resin layer 2 include polyolefin synthetic resins such as polypropylene and ethylene-propylene copolymer, which have excellent heat resistance against high temperatures during retort sterilization.

It is preferable to add an inorganic filler such as calcium carbonate to the resin. In addition, pigments and various additives may be added.

The above-described materials can be used for the synthetic resin tab 4 and the synthetic resin pillar 12.

According to the present invention, by attaching the synthetic resin pillar 11 to the back surface of the bottom 1A of the base material 1 for lid of a can-like container, the thickness is partially increased over the entire bottom of the lid 8. As shown by the arrow in Figure 1, when pressure inside the can is applied, it is possible to prevent the bottom from curving in the negative direction. A cut 13 is provided on the back side of the IA,
Since the cut 13 acts in the direction of closing the gap between the cuts 13 when the pressure inside the can increases, the resistance to the pressure inside the can can be improved. On the other hand, the cut 13 acts in the opposite direction to widen the gap in the direction of opening the can from above as indicated by the arrow in FIG. 1, so that it does not impair the ease of opening. Further, by attaching the machine 12, the strength of the lid 8 was reinforced, and the strength of the lid 8 to be dropped could be improved.

Although the invention made by the present invention has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above-mentioned Examples and can be modified in various ways without departing from the gist thereof. do not have.

For example, in the embodiment described above, the synthetic resin columns were provided in a grid pattern, but they may be provided in only one direction. Further, in the above embodiment, an example in which cuts are provided only in the horizontal direction is shown, but cuts may also be provided in the vertical crosspieces.

In addition to the lids shown in this embodiment, the present invention is also applicable to lids in which an exposed surface of the base material for can-like container lids is provided at the bottom of the tab in order to improve the strength of can-like container lids, for example, in order to improve the strength of can-like container lids. The surface is coated with a thin injection resin layer to create tambour resistance [
It can be applied to various plastic lids, including those with improved tamper-proof function.

[Effects of the Invention] According to the present invention, in the pressure-resistant plastic lid,
It has been possible to provide a technique that can improve resistance to internal pressure while not adversely affecting can drop strength and ease of opening.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the lid showing an embodiment of the present invention, Fig. 2 is a perspective view of the lid as seen from the bottom side, Fig. 3 is an enlarged explanatory view of the Δ section in Fig. 2, and Fig. 4 is a conventional example. 5 is a top view of the lid showing the 4th
1-1 line sectional view, FIG. 6 is a perspective view of the can-like container, FIG. 7 is a rear view after opening the lid shown in FIG. 4, and FIG. 8 is FIG. 7 II.
-II line sectional view and FIG. 9 are perspective views seen from the bottom side of a lid showing a conventional example. 13 - Base material for can-like container lid Injection resin layer Score part Synthetic resin tab Plastic lid Can-like container body Can-like container Synthetic resin pillar cut

Claims (1)

[Claims] A pressure-resistant plastic lid attached to the body of a pressure-resistant can-like container, comprising a gas barrier multilayer base material with a multilayer structure having a synthetic resin layer on the surface layer that can be thermally bonded to the body, and a bottom part and the bottom part. A can-like container lid base material in which a rising portion erected on the outer periphery and a flange portion curved outward from the rising portion are formed, and on the outer surface of the can-like container lid base material, A synthetic resin laminated by injection molding (hereinafter referred to as the injection resin layer) having a part on the peripheral end that can be attached to the body, and a score part provided in the part where an opening is required.
A plastic lid comprising a synthetic resin tab attached to the upper surface of the injection resin layer that can be opened by cutting the score portion, the bottom back surface of the can-like container lid base material of the lid. A pressure-resistant plastic lid characterized in that synthetic resin bars having cuts formed from below toward the back surface of the bottom are attached in a grid pattern or only in one direction.