WO2005037677A1

WO2005037677A1 - Closure for containers and method for the production thereof

Info

Publication number: WO2005037677A1
Application number: PCT/EP2004/011509
Authority: WO
Inventors: Frank Schellenbach
Original assignee: Frank Schellenbach
Priority date: 2003-10-13
Filing date: 2004-10-13
Publication date: 2005-04-28
Also published as: CA2545836A1; AU2004281942A1; EP1673289A1; BRPI0415461A

Abstract

The invention relates to a closure (1) for food storage containers, in particular for beer bottles and the like, said closure having a sealing face, for sealing the container or bottle opening. Said closure (1) is made of a support material and an oxygen scavenger, whereby the sealing face (4) of the closure (1) has an active surface, which is enlarged in relation to a substantially planar and/or smooth sealing face. Said sealing face (4) may be integrally embodied with the closure, in particular with the closing material. Alternatively, the sealing face may also be formed by a separate sealing element, in particular by a sealing disc, arranged inside the closure, or by a shaped sealing liner.

Description

Closure for containers and process for their manufacture

The invention relates to a closure for containers for storing food, in particular for beer bottles, and a method for producing such a closure.

Sealing caps for containers for storing food, in particular for beverage bottles, are generally formed in two parts. They consist of a cap and a sealing element in the form of a separate sealing ring or a circular sealing washer. Due to its strength, the harder cap ensures that the cap is held on the container. The sealing washer, which is inserted into the cap, is softer and fulfills the sealing function by pressing against the edge of the opening of the container. However, there are disadvantages in the manufacture and disposal of these closures. In this way, the cap and sealing disc are manufactured independently of one another and then joined into one another before the filled container or the filled bottle is closed. In particular before recycling, the components of the closure have to be separated again.

However, one-piece closures for bottles for soft drinks have already been proposed, for example in PCT / EP99 / 01357. These closures are made of plastic, especially polyethylene. The material of the closures is among others

determined that no material should get into the food from the cap. In addition, both the locking function, the sealing function and, under certain circumstances, the guarantee function must be fulfilled by a guarantee tape. For this purpose, different, sometimes contradicting requirements must be met when choosing the material and designing the closure. For example, the material must be hard enough to provide a secure hold for the cap screwed onto the bottle, and soft enough to ensure that it seals when pressed onto the bottle neck. The PE material can perform a secure sealing function, a good sealing function and, under certain circumstances, the guarantee function with a guarantee band. In the case of perishable foodstuffs, for example beer, there is also the problem that the oxygen enclosed in the container or penetrating into the container has a negative effect on the shelf life of the product and the prescribed shelf life guarantees cannot be fulfilled. For this reason, the bottle must either be deprived of oxygen when the bottle is closed or the oxygen contained in the bottle must be reduced.

For this purpose, closures, in particular for beer bottles, are equipped with a sealing disc which has an oxygen scavenger, ie a material with oxygen-scavenging or oxygen-withdrawing properties. Such oxygen scavengers are, for example, from EP 0 664 824 Bl. The sealing washers are approximately 0.28 mm thick, soft and must contain "oxygen scavenger" material in a certain minimum amount in order to provide sufficient oxygen scavenging capacity. Upon contact with the high humidity inside the container or bottle, these materials are activated after they have been stored dry before use and remove the oxygen from the inside of the container. They can also reduce the diffusion of oxygen into the interior of the container.

The closures used are, as described above, in two parts. The sealing disc must be made in addition to the cap and then joined together before closing the bottle. Alternatively, coatings can also be implemented inside and on the surface of the packaging materials. A one-piece cap, on the other hand, would be desirable for manufacturing reasons as well as for easier disposal and cheaper recycling.

So far, however, it has not been possible to produce a one-piece closure that satisfactorily fulfills the closure function, the sealing function and the deprivation of oxygen for the preservation function. The “oxygen scavenger” materials are soft and thus counteract a secure closure. A reduction in the proportion of “oxygen scavenger” material in the material of the closure cap could contribute to an increase in strength, in particular the required stress crack resistance of the closure. However, the guarantee requirements are then no longer met, since the oxygen scavenging capacity drops too much with a lower concentration of the "oxygen scavenger".

The object of the invention is to provide a closure which, in addition to the closure function, ensures a reliable sealing function and, moreover, also a very effective oxygen removal for the preservation function. According to a further aspect of the invention, this is to be ensured in particular for a one-piece closure for a container for storing food, in particular such as beer bottles, which is characterized by simple manufacture and a secure closure, as well as an effective preservation function for perishable foods.

According to the invention, this object is achieved by the measures of claim 1. For the manufacture of a one-piece closure, the solution is in accordance with the characterizing features of claim 3. However, the invention also relates to the provision of a sealing material or a liner for a closure, with which, in particular, effective oxygen removal and a good sealing function are ensured. To this end, the solution results from the features of the characterizing part of claim 2.

The invention is characterized in that the sealing surface of a closure is enlarged with respect to its active surface by providing it with an active surface which is enlarged compared to an essentially flat or smooth sealing surface. Such an enlargement of the effective sealing surface can be achieved in particular by eroding the sealing surface or by providing the sealing surface or the sealing element with projections and / or depressions for the purpose of enlarging the active sealing surface. This results in a roughly structured surface with a larger effective contact area and thus increased oxygen absorption.

Advantageously, the closure, in particular for use in beer bottles, is made in one piece from a material which contains a carrier material and an oxygen scavenger. Any oxygen scavenger known, for example, from the above-mentioned publication can be used as the oxygen scavenging material. However, the invention is not intended to be limited to these substances, but rather to include all possible suitable oxygen scavengers. Oxygen deprivation can be based, for example, on absorption, adsorption or other chemical reactions. The sealing surface which is in contact with the interior of the container is provided with an active surface which is enlarged compared to the active surface of a substantially flat or smooth sealing surface, so that a larger active surface is provided which removes oxygen from the interior of the bottle , The effectiveness of the oxygen uptake is increased in this way with a constant proportion of oxygen scavengers in the carrier material. The proportion of soft “oxygen scavenger” materials in the material of the closure cap can be reduced at least to such an extent that the strength of the closure, in particular the resistance to stress cracking, is sufficient to ensure a reliable closure function. oxygen scavengef material should be selected in such a way that due to the increased active oxygen-trapping area, so much oxygen can be extracted from the vessel that the required preservation requirements are met, so that the conflicting requirements for securing the closure function, the sealing function and the The size of the active surface of the sealing surface and the proportion of "oxygen scavenger" material are selected taking into account the other size. There is also the advantage that the closure can be manufactured in a single injection molding process due to the one-piece design. The second injection molding process required with conventional closures and the joining of the sealing washer with the closure cap are dispensed with. This results in a simplification of production and advantages in disposal or recycling.

According to a further independent concept, the sealing surface is formed by a separate sealing element, in particular a sealing disk arranged in a closure, or the sealing surface can be formed by a sealing liner molded onto the closure. The advantages of the inventive concept of the enlarged active sealing surface of a sealing element can thus also be applied to other, in particular conventional, closures or closure caps. The sealing element is nem oxygen scavenger, but has a significantly increased effective surface, which increases the oxygen deprivation and thus the preservation function is optimized. This can also be achieved with a separately molded liner on a closure. In the context of the invention, independent protection of such a sealing element, in particular in the manner of a sealing washer or linder, is therefore also claimed.

The enlargement of the sealing surface can in particular be achieved in that the active surface is at least partially formed by rough eroding of the sealing surface. In this context, rough erosion means rough roughening of the sealing surface.

The active surface of the sealing surface can have a structure with projections and / or depressions to enlarge the active surface. The shape and the dimensioning of the projections and the depressions can be chosen so that the size of the active area is sufficient for the fulfillment of the preservation function.

The enlarged active surface is preferably formed by punctures in the sealing surface. This measure can be particularly effective since the depth and the extent of the punctures can be selected so that the necessary active surface is achieved.

The enlarged active surface of the sealing surface can also be formed by a wave-like or rib-like structure in the sealing surface.

The active surface of the sealing surface will preferably be enlarged 2 to 3 times compared to an essentially smooth or flat sealing surface.

The closure is preferably made of plastic.

A polymer composition is generally used as the carrier material for this purpose. For example, polyethylene (PE) can be selected as the carrier material. On the one hand, polyethylene can guarantee the sealing function, on the other hand, it has the strength necessary to close the bottle.

In particular, an oxygen scavenger is used, which is activated by water or water vapor.

In addition, the material of the closure may further contain a catalyst to increase the rate of reaction of the oxygen scavenger with the oxygen.

The proportion of oxygen scavenger in the closure can in particular be selected such that the closure has the required strength to ensure the closure function on the one hand and the required oxygen scavenging capacity to guarantee the shelf life requirements for the food on the other.

The one-piece closure is usually designed as a twist lock. In principle, however, the invention can also be applied to detachable closures, such as crown caps, or twist-off crown caps.

The closure preferably has a guarantee band for fulfilling the guarantee function.

The closure can have an inner seal which presses against the inner wall of the container when the container is closed.

In addition, the closure can comprise a wedge seal which, when the container is closed, rests on its upper edge at the transition into the interior of the container.

Furthermore, the closure can have a cap wall with an annular seal, which lies against the outer wall of the container when the container is closed. In addition, the closure can have a tear-off guarantee band to fulfill a guarantee function.

A method for producing a closure described above comprises the steps of: producing a mixture comprising a carrier material and an oxygen scavenger; and producing the one-part closure from the mixture by injection molding, the active surface of the sealing surface of the closure being roughly eroded Compared to the manufacturing methods for conventional closures, the method eliminates at least the steps of manufacturing a sealing washer and assembling the sealing washer with the sealing cap, thereby reducing the effort and costs.

Further features and advantages of the invention result from the following exemplary embodiment.

The figure shows a sectional view of a closure for a beer bottle according to the invention.

An inventive closure 1 for a bottle, whether made of glass or plastic, is shown in the figure. An internal thread 9 is formed in the side wall 2 of the cap of the closure. The end wall 3 of the closure 1 has a sealing surface 4 which is in contact with the inside of the closed bottle.

On the end wall 3 there is an annular inner seal 5 which projects to the open end and is spaced apart from the cap wall 2. Their outer diameter tapers in the area of their free end. A bulge 5a is formed towards the cap wall 2, which bears against the inside of the bottle neck when the bottle is closed. The bead 5a comprises the area 5b which tapers in the outer diameter.

The inner surface 5c of the inner seal 5, on the other hand, runs essentially perpendicular to the sealing surface 4. On the side facing the cap wall 2, the inner seal 5 extends approximately in an arc shape to the bead 5a, that is to say it merges with the bead 5a, and tapers from there again in a roughly straight line in the outer diameter. The bead 5a is dimensioned or extends in such a way toward the cap wall 2 that the inner seal 5 or the bead 5a is pressed against the inner wall of the bottle in the region of the bottle mouth in the screwed-on state with a predetermined contact pressure.

The figure further shows that the end wall 3 in the area between the cap wall 2 and the inner seal 5 has a wedge seal 6 protruding from the end wall 3 and inclined towards the inner seal 5. The wedge seal 6 is positioned and dimensioned such that, in the screwed-on state, it bears against the radius or against the inside edge of the bottle neck or at the transition into the bottle mouth. This wedge seal 6 tapers to its free end.

It is also shown that the cap wall 2 in the upper region, i. H. in the area shortly before the transition to the end wall 3, has an approximately radially or inwardly projecting annular seal 7 for contacting the outer wall of the bottle neck. The seal 7 is dimensioned in such a way that it bears against the outer wall of the bottle under tension in the screwed-on state.

Caps with which beverage bottles or similar containers can be closed have to meet different requirements. On the one hand, the sealing of the beverage bottles or containers must be achieved in such a way that the beverage contained in them cannot escape from the container in the closed or locked state. If the containers to be sealed are beverage bottles, this requirement is determined by the viscosity of the liquid. Are the drinks contained in the bottles also with a pressurized gas such. B. carbonated, then the seal must also be gas-tight to prevent the gas from escaping from the bottle. Relatively high internal pressures can also arise in beer bottles, so that a secure and firm seal is required to prevent the gas from escaping. The invention achieves adequate sealing for the internal pressures which arise and for external loads. The seal can also be achieved in that a corrugated, ribbed structure is provided, which presses the sealant specifically against the upper edge of the container, thereby creating a sealing zone in which the sealant is pressed against the upper edge of the container with high pressure.

Furthermore, according to the figure, an annular guarantee band 8, which adjoins the cap wall 2 and can be torn off at a predetermined breaking point, is provided. The guarantee band 8 has, for example, two predetermined breaking points, which lie opposite one another, so that the guarantee band 8 is divided into roughly equal halves when torn open.

The closure cap according to the invention is made in one piece overall. The closure is made of a material which contains polyethylene as a carrier material and an oxygen scavenger. The one-piece design results in production advantages and disposal advantages.

As shown schematically in the figure, the sealing surface 4 is roughly eroded in order to enlarge the active surface, which is intended to extract oxygen from the inside of the bottle, compared to an essentially flat or smooth sealing surface. In this case, the enlargement of the active surface was achieved by a large number of depressions in the sealing surface. By a suitable selection of a proportion of “oxygen scavenger” in the carrier material and by the roughly eroded and thus enlarged sealing surface, the opposing requirements of a high strength of the closure cap for the closure function and a high oxygen-intercepting effect for the preservation function can be fulfilled at the same time "Oxygen scavenger" within the closure material can be significantly reduced without the oxygen trapping capacity falling too much. At the same time, the cap receives the necessary crack resistance to ensure a secure closure function. This enables a one-piece design of the closure cap, which makes it easier to manufacture. In addition, material costs can be saved by reducing the relatively more expensive oxygen scavenger. A two to three times enlargement of the active area is usually sufficient for the purposes mentioned. It may be sufficient to only partially roughen the sealing surface. Likewise, the inner surface 5c and / or the tapered area 5b of the inner seal 5 can also be eroded. In this way, a maximum active area that removes oxygen from the inside of the bottle can be created.

The active area can be eroded in different ways. The only important thing is that the active surface is enlarged compared to a surface that is essentially not roughened. The surface can be provided, for example, with recesses, waves, ribs, lamellas, depressions, projections, etc.

The subject of the application is not limited to closures for closing beer bottles. Rather, the closures are suitable for any type of container, for example for any type of food container. Furthermore, the closure cap according to the invention can be used both for reusable bottles and for disposable bottles. The closures are suitable, for example, for beer bottles that are packaged in a sealed six pack. In addition, the invention can be used not only in connection with screw caps, but also with crown caps, e.g. rotatable crown caps or detachable caps can be used.

Claims

Patentansprflche

1. Closure for containers for storing food, in particular for beer bottles and the like, with a sealing surface for sealing the container or bottle opening, characterized in that the closure (1) consists of a carrier material and an oxygen scavenger. is constructed, the sealing surface (4) being equipped with an active surface which is enlarged compared to that of an essentially flat or smooth sealing surface.

2. Closure according spoke 1, characterized in that the sealing surface is formed by a separate sealing element, in particular a sealing washer arranged in the closure or molded sealing liner.

3. Closure according to claim 1, characterized in that the sealing surface (4) is formed in one piece with the closure, in particular the closure material.

4. Closure according to one of claims 1 to 3, characterized in that the active surface is at least partially formed by rough erosion of the sealing surface (4).

5. Closure according to one of claims 1 to 4, characterized in that the sealing surface (4) has projections and / or depressions to enlarge the active surface.

6. Closure according to one of the preceding claims, characterized in that the enlarged active surface is formed by punctures in the sealing surface (4).

7. Closure according to one of the preceding claims, characterized in that the enlarged active surface is formed by a wave-like or rib-like structure in the sealing surface (4).

8. Closure according to one of the preceding claims, characterized in that the active surface of the sealing surface (4) compared to an essentially smooth or flat sealing surface is enlarged by a 2 to 5 times.

9. Closure according to one of the preceding claims, characterized in that the closure (1) is made of plastic.

10. Closure according to one of the preceding claims, characterized in that the carrier material is a polymer composition.

11. Closure according to one of the preceding claims, characterized in that the carrier material is polyethylene (PE).

12. Closure according to one of the preceding claims, characterized in that the oxygen scavenger is activated by water or steam.

13. Closure according to one of the preceding claims, characterized in that the material of the closure further contains a catalyst for increasing the reaction rate of the oxygen scavenger with the oxygen.

14. Closure according to one of the preceding claims, characterized in that the proportion of oxygen scavenger ("oxygen scavenger") is selected so that the closure (1) has a required strength to ensure the closure function and a required oxygen trapping capacity to ensure the shelf life requirements for the food having.

15. Closure according to one of the preceding claims, characterized in that the closure (1) is designed as a twist lock.

16. Closure according to one of the preceding claims, characterized in that the closure (1) has an inner seal (5) which presses against the inner wall of the container when the container is closed.

17. Closure according to one of the preceding claims, characterized in that the closure (1) comprises a wedge seal (6) which, when the container is closed, rests on its upper edge at the transition into the interior of the container.

18. Closure according to one of the preceding claims, characterized in that the closure (1) has a cap wall with an annular seal (7) which bears against the outer wall of the container when the container is closed.

19. Closure according to one of the preceding claims, characterized in that the closure (1) has a tear-off guarantee band (8).

20. A method for producing a closure according to one of claims 1, 2 or 4 to 19, comprising the steps of: producing a mixture comprising a carrier material and an oxygen scavenger; and producing the one-part closure from the mixture by Injection molding, the active surface of the sealing surface (4) of the closure being roughly eroded.