EP0778224A1 - Gastight container - Google Patents

Abstract

The gas-tight container has a part surface which can become curved, and around which is a continuous bead (3). In the form ready for use, this part surface is concave. The part surface is in the bottom (5) of the container, or itself forms the bottom of the container. The concave curvature in the form ready for use does not extend beyond the outer limits of the bottom edge (2). When the pressure inside is high, at normal external pressure, the concave curvature does extend beyond the outer limits of the bottom edge.

Description

The present invention relates to a gas-tight container, the bottom-side container edge of which rests in a line or ring on a base, containing a jacket surface made of metal or metal and plastic or metal and cellulose-containing material, and the jacket surface is composed of the bottom, lid and at least one side wall, the Shell surface has at least one curvilinear partial surface, which is surrounded by an endless bead and the partial surface in the use form of the container has a concave curvature. The invention further relates to the use of the container.

It is known to fill decomposable or perishable goods in order to protect them from external influences such as light, air, bacterial contamination, drying out, hygroscopic influences etc., in gas-tight and also radiation-impermeable containers and to seal the containers gas-tight. Typical containers of this type are food cans containing food for humans and animals or beverage cans, but also containers for pharmaceutical, cosmetic or medical products, as well as cleaning agents, pesticides and solvents, in particular on a biological basis, etc.

For example, due to microbial influences or chemical decomposition, gases can form in the container, for example in a can, which increase the internal pressure. When opened, this increased internal pressure leads to eruptions and, in some cases, to sudden and unwanted escaping of the can contents.

In addition to aspects such as pollution of the environment or even injuries to the person opening such a can, this leads to annoyance and resentment towards the manufacturer because inedible or unusable goods have been bought and problems with return and replacement have been negotiated.

The object of the present invention is to provide a solution with which it can be easily seen on a container that its contents have been subject to deterioration or decomposition.

According to the invention, this is achieved in that the partial surface is arranged in the base or the partial surface forms the base and the concave curvature in the use form does not protrude beyond the outer boundaries of the container rim on the bottom and the concave curvature, which is shaped to the outside under increased normal pressure and external normal conditions, is formed projects beyond the outer boundaries of the bottom edge of the container, the linear or ring-shaped support of the container edge on a base of a two-point support gives way and the container indicates a chemical or physical change in the contents due to an unstable position on a base.

The partial surface of the container advantageously has the concave curvature at normal internal pressure, which does not protrude beyond the outer boundaries of the bottom edge of the container, and at increased internal pressure under external normal conditions, the concave curvature is shaped into a convex curvature which protrudes beyond the outer boundaries of the bottom edge of the container .

The outer surface of the container made of the bottom, lid and one or more side walls can be, for example, a can with a polygonal, round or oval cross-section in plan view. Depending on the polygonal cross section, the box can have several side walls or, in the case of a round or oval cross section, an endless side wall. The side walls of the container end at a bottom edge of the container, which is e.g. a flanged edge, a fold, a connecting seam or by simply bending or bending the outer surface can be formed. The bottom edge of the container can have a linear or ring-shaped support surface on a flat or. form a smooth surface.

In addition to the side wall or the side walls, the container can have a bottom and a lid or can only have a bottom, the lid being formed by the dome-like retracted side wall or, in the case of a polygonal plan, by the side walls.

Other forms of containers are, for example, cups, tapestries, bowls, bottles, canisters or cans.

The material of the outer surface can be made of metal, for example, such as steel, iron, tin, zinc, galvanized iron, copper, aluminum and its alloys, tinplate, etc. The metal is preferably processed in the form of foils, strips or circular blanks and can be manufactured on Containers for example have a thickness of 10 microns to 400 microns. The metal can be coated on one or both sides with layers of metal such as tin; Chrome; Nickel or made of plastic, such as lacquers, extrudates, foils or foil composites, and can therefore also be a composite material. The metal can also be coated on one side with a cellulose-containing material, such as paper, cardboard or cardboard. Furthermore, it is possible to coat the metal on one side with the specified cellulose-containing materials and on the other side with the specified plastic layers. With such materials, for example, changing boxes can be produced. Shell surfaces made of metal are preferred.

Suitable plastics are e.g. thermoplastic or thermosetting plastics, which may be reinforced by fillers or fibers, knitted fabrics or fabrics. The plastics can contain or consist of polyvinyl chlorides, polyolefins, polyamides, polycarbonates, polyesters, acrylonitrile, methacrylonitrile, styrene, copolymers of acrylonitrile and styrene, copolymers of acrylonitrile, styrene and butadiene, epoxy resins, etc.

The different parts of the containers can also be made of different materials. For example, the side wall can be made of cellulose-based material combined with metal and the bottom and the lid can be made of plastic and metal.

Depending on the rigidity of the material, it can be advantageous for at least one further endless bead to be arranged in the partial area which is surrounded by an endless bead. The further bead or a plurality, for example 2, 3, 4, 5 and 6 further beads, can be arranged one inside the other and also arranged one inside the other in concentric circles or ovals. Embossing or deepening, etc. are synonymous with beads.

From the center of the partial area, further beads or embossing can be provided, running in a star shape against the edge of the container.

A single corrugation or one of the inner corrugations, in particular the innermost corrugation, can limit an outward protrusion or bulge in relation to the container. Such a protuberance or bulge or elevation can e.g. in the form of a spherical segment, a pyramid, a truncated pyramid, a cone or a truncated cone.

A container according to the invention is advantageous, in the partial surface of which is surrounded by an endless bead, at least one protuberance is arranged, which in use form does not protrude beyond the outer boundaries of the bottom edge of the container and, with increased internal pressure, protrudes beyond the outer boundaries of the container rim on the bottom, the lines protruding - Or annular support of the container edge, especially on a flat surface, gives way to a two-point support.

The partial surface, which has a concave curvature in the use form, jumps outwards when there is overpressure in the interior of the container, i.e. the partial surface that is initially more or less dented towards the inside of the container pops out or bulges out and can form a convexly shaped partial surface or a curved outer surface. The terms concave and convex refer to a viewer looking at the outside of the container.

The partial surface of the lateral surface, which in use form has a concave curvature, is arranged in the base or the partial surface forms the base itself and the base has a concave curvature. In use, the concave curvature does not protrude beyond the outer boundaries of the bottom edge of the container, i.e. The container stands stable on a level surface on the line or ring-shaped container edge. If the internal pressure in the container is increased, the concave curvature is deformed outwards into a convex curvature and the convex curvature projects beyond the outer boundaries of the bottom edge of the container. The linear or ring-shaped support of the container edge, in particular on a flat surface, then gives way to a two-point support in the case of a round container edge at the bottom, and a container, such as a can in a cylindrical shape, will stand at an angle and roll along its container edge even with slight force. Analogously, a container of polygonal shape will show a line and a dot support instead of the linear or ring-shaped support and the container will be inclined on a flat surface.

In practice, this means that not only does the visual effect of the protruding partial surface become effective, but that containers of this type are unstable on a flat surface, are slightly inclined and incline or turn with the slightest touch. This effect is particularly effective, for example in the case of cans containing food for humans or animal feed. Due to the oblique and occasionally unstable position of such cans on the shelves of a retail store, cans with spoiled contents are immediately apparent.

Containers according to the present invention can be manufactured in different ways. For example, cans can have a rounded or folded side wall and one or more glued, welded and / or flanged seams or seams in the side wall. The bottom and the lid can be cast, punched, shaped and then glued, welded, rolled or flanged at the ends of the side wall. The partial surface can, for example, be embossed in the floor during the manufacturing process.

Other containers are, for example, from a side wall made of composites parallel or spiral-wound composites containing plastics, plastic-paper, paper-metal foil or plastic-metal foil etc. and the bottom and lid are e.g. made of metal with plastic.

Containers which are preferably used are made of metal, such as steel, tinplate, chrome-plated or nickel-plated steel sheet, aluminum etc. or of laminates containing aluminum, steel and plastic layers. For example, it is made from a metal strip Rondelles punched out. The rondelles are deformed into shell-like preforms. The preforms are drawn through a series of drawing rings by means of a stamp which contains an insert for forming a base at the lower end. Towards the end of the drawing step, the stamp hits a die for the bottom contour, the material located between the punch and the die deforming into a correspondingly contoured bottom. By ironing, one-piece cans are produced, which after filling only have to be provided with a lid, for example with a lid with a zipper. The lid can, for example, be crimped, glued or welded on. During the ironing process, a contour with at least one bead can be embossed on the base which forms between the punch and the die, the base or part of the base then forming the partial surface

A preferred embodiment of the container according to the invention consists in that the partial surface, which in use form has a concave curvature, is the bottom, the side wall is shaped into a cylinder and the lid contains a zipper

The depth of the bead which delimits the partial area and the number and depth of the beads in the partial area can depend on the force which will later be required in use of the container in order to push the concave-shaped partial area outwards or the concave-shaped partial area impose convex shape.

In practice, the shapes of the partial areas can easily be determined by preliminary tests and the limit value of the internal pressure at which the partial area changes from the concave shape to the convex shape, flowing or erratic, can be selected. This can be done through the choice of material, preferably sheet steel, tinplate, chromed or nickel-plated steel sheet (tin free steel = T F S), aluminum, composites made of metals and plastics or composites made from metal and paper for changing boxes and through the material thickness, e.g. 60 to 400 and in particular 80 to 300 microns. The depth of the beads can e.g. 0.2 to 25 mm. The number of beads can e.g. 1, 2 or 3. The size of the partial area can preferably correspond to the entire floor area.

In the case of the gas-tight containers according to the invention, the volume difference in the container, between the initial volume with the partial surface with concave curvature and the state in which the curvature is shaped outwards or the partial surface has a convex curvature and projects beyond the outer limits of the bottom-side container edge, with increased internal pressure and under normal external conditions, for example up to 14 cm ³ , expediently 0.5 to 12 cm ³ , advantageously 1 to 10 cm ³ and particularly advantageously 2 to 5 cm ³ .

Under normal conditions, for example, temperatures in the region of room temperature, i.e. approx. 15 to 30 ° C, and the ambient pressure, i.e. around 1 bar, understood.

In industrial application, existing containers are usually shaped, if necessary lacquered, filled and gas-tightly covered, further process sequences such as shaping the side wall, attaching the bottom, filling and covering, etc. are also possible. After filling and before or especially after capping, the containers can be subjected to a sterilization or pasteurization treatment at temperatures up to 130 ° C or higher. Depending on whether the sterilization or pasteurization treatment is carried out with or without back pressure, the internal pressure increased under this heat load can result in a corresponding volume expansion. The partial surface can protrude from the concave to the convex shape. Due to a tendency to spring back, the concave shape must be restored when the container cools down with the decrease in internal pressure with respect to the partial surface. The same can occur in the case of external heat, such as strong sunlight and the like.

If such a gas-tight container is now stored and the contents e.g. the chemical reaction or microbial influence, such as spoilage or fermentation, with the evolution of gas, increases the internal pressure. Here, the partial surface with the concave shape is deformed, flowing or erratic, and changes into a convex shape.

For example, this applies to a metal can, e.g. an aluminum can, the internal protective coating of which is inadequate or has been damaged and aggressive, aqueous contents lead to corrosion due to an acidic or alkaline reaction. The aluminum is converted to aluminum oxide and hydrogen develops, which creates the internal pressure in the container.

It can be fermented by fermenting a content e.g. Carbon dioxide is produced in the area of nutrition for humans and animals, whereby the internal pressure in the container increases.

The present invention also relates to the use of the present containers for holding fill goods, such as substances which are subject to microbial and / or chemical degradation.

A preferred use of the container is to take up substances from the series of foods for humans and animal feed, in each case in particular in pasty to small-sized form.

Therefore existing containers are suitable e.g. for filling goods, such as water-containing foods with a pH of less than 5, such as freshly processed fruits, "mixed pickles", acidic, non-carbonated or low-carbonated beverages, or meat products, meat preparations, ready meals, animal feed, such as protein and / or starchy preparations in pasty to lumpy form, with a pH above 5, and also cosmetic or pharmaceutical-medical products, cleaning agents, pesticides, fertilizers or other substances.

1 to 5, the present invention is further illustrated by way of example on a container in the form of a can.

Figures 1a, 1b and 1c each show a cross section through differently shaped can bases.

Figure 2 shows the top view of a can bottom.

Figures 3a, 3b and 3c show the top view of a can bottom and two cross sections through the can bottom.

FIG. 4 shows a further embodiment of a can base with an out-of-center protuberance.

FIG. 5 shows the top view of another embodiment of a can base, the cross section through the can base being shown in FIG. 1c.

FIGS. 1a, 1b and 1c show, by way of example, different embodiments of can bases 5, which in the present case are formed, for example, by punching them out of a trellis, by shaping a shell-like preform and by ironing them into a one-piece can. For ironing, a stamp is used, which forms the actual can from the preform, an insert for shaping the base being attached in the base of the stamp and in the last working cycle of ironing, the base of the stamp is pressed against a die for the base contour, the Beads 3 and the protuberance 4 are molded.

In Figures 1a, 1b and 1c, the side wall 1 of a can can be seen, which passes over an edge or bead 2, which also forms the support surface for the can when standing vertically. The edge bead 2 represents the outer boundary of the container on the bottom side. Various beads 3 with different kink radii or arc radii are molded in and in the center a protuberance 4 is attached which, in the present case, does not protrude beyond the edge bead 2 with respect to a flat surface. FIGS. 1a and 1b show relatively deeply shaped beads and in each case the protuberance 4 in the center of the bottom 5, while in FIG. 1c a large number of fine beads 3 and the protuberance 4 arranged in a curvature can be seen.

With increasing internal pressure, the can base 5 bulges outwards and the protuberance 4 projects beyond the outer boundary formed by the edge bead 2. So that the box is at an angle and instead of the linear support over the entire rim on a flat surface, a two-point support has been used, which the stability or. Tilt resistance of the can influenced.

FIG. 2 shows a top view of a can base 5, again the edge bead 2, the beads 3 and protuberance 4 being recognizable.

FIG. 3a shows a further embodiment of a can base 5, a bead 3 being arranged concentrically therewith within the edge bead 2. A protuberance 4 is embossed in the center of the can base 5. FIG. 3b shows the can bottom 5 from FIG. 3a in section, the side wall 1 being delimited by the edge bead 2. The bead 3 is arranged concentrically to the bead 2 and the can bottom 5 continues under a concave curvature up to the center, which is formed by the protuberance 4. The can is in the form of use and the edge bead 2, as well as the protuberance 4, lie on a flat surface. FIG. 3c shows the same can as in FIG. 3b, with the side wall 1 and the edge bead 2, the bottom 5 being pressed outward by increased internal pressure, deforming along the bead 3 and deforming the bottom inside the bead 3. The can only stands with the protuberance 4 and punctiform with the bead 2 on the flat, flat surface, i.e. the standing position of the can is slanted and shaky.

In Figure 4, the circular edge bead 2 of a can base 5 is shown in plan view. The partial area is delimited by an oval endless bead 3 and a protuberance 4 is arranged off-center. With increased internal pressure of a can with such a bottom the concavely inwardly shaped partial surface is curved outwards, advantageously convexly outwards, at least the formation 4 protruding beyond the edge bead 2 and bringing the can into an unstable standing position.

FIG. 5 shows a further possible embodiment of a can base 5. Surrounded by the edge bead 2 is a concavely curved partial surface which is shaped by a plurality of beads 3 arranged concentrically in a ring. A protuberance 4 is arranged in the center and further beads 6 running outwards are arranged in a star shape from the center. In cross section, such a can bottom can correspond to the illustration according to FIG. 1c.

Typical examples of cans that can be used in practice are, for example, two-part cans, i.e. Cans from a lid and from a bottom and side wall part molded in one piece, which can be filled, for example, with contents of 100 to 800 g. For cans with a content of 800 to over 1200 g, for example, three-part cans, i.e. Cans from bottom, lid and side wall preferred. The lids can be, for example, easy-to-open lids which have notched and fastened a tear ring within the notch, or which are easy to open via an edge seam.

It can easily be seen from FIGS. 1a to 1c that even a slight bloating of the base, which is caused by only a slight increase in the internal pressure, leads to an unstable standing position of the can via the contact of the protuberance 4 with the base. The partial areas can be designed in such a way that, for example, with a pressure difference between the external pressure and the internal pressure of the can of 0.1 to 1 bar, the protuberance takes place, response values of 0.2 to 0.7 bar being preferred. In the transition from the concave to the convex shape of the partial surface, for example, there should be a height difference of at least 0.5 mm, expediently at least 1.0 mm between the can contact surface, formed by the protuberance 4 and the edge bead 2.

Claims (9)

Gas-tight container, the bottom-side container edge of which rests in a line or ring on a base, containing a jacket surface made of metal or metal and plastic or metal and cellulose-containing material, and the jacket surface is composed of bottom, lid and at least one side wall, the jacket surface having at least one curvature Has partial area which is surrounded by an endless bead and the partial area in use form has a concave curvature,
characterized in that
the partial area is arranged in the floor or the partial area forms the floor and the concave curvature in use form does not protrude beyond the outer boundaries of the bottom-side container edge and, with increased internal pressure and external normal conditions, the concave curvature is shaped into a curvature which defines the outer boundaries of the bottom-side container edge protrudes, the linear or ring-shaped support of the container edge giving way to a base of a two-point support and the container indicating a chemical or physical change in the content due to an unstable position on a base. Gas-tight container according to claim 1, characterized in that at least one further endless bead is arranged within the partial area which is surrounded by an endless bead. Gas-tight container according to claim 1, characterized in that the partial surface, which in use form has a concave curvature, is the bottom, the side wall is shaped into a cylinder and the lid contains a zipper. Gas-tight container according to claim 1, characterized in that the volume difference in the container, between the initial volume with the partial surface with concave curvature and the partial surface in a curvature which projects beyond the outer limits of the bottom-side container edge, with increased internal pressure and under external normal conditions, up to 14 cm ³ , expediently 0.5 to 12, advantageously 1 to 10 and advantageously 2 to 5 cm ³ . Gas-tight container according to claim 1, characterized in that the outer surface is formed from metal. Gas-tight container according to claim 1, characterized in that in the partial area, which is surrounded by an endless bead, at least one protuberance is arranged, which in use form does not protrude beyond the outer boundaries of the bottom edge of the container and, when the internal pressure is increased, protrudes beyond the outer boundaries of the container rim at the bottom , wherein the linear or ring-shaped support of the container edge, in particular on a flat surface, gives way to a two-point support. Gas-tight container according to claim 1, characterized in that, under normal internal pressure, the concave curvature does not protrude beyond the outer boundaries of the bottom-side container edge and, at increased internal pressure, the concave curvature is shaped into a convex curvature which projects beyond the outer boundaries of the bottom-side container edge. Use of the container according to claim 1 for receiving substances which are subject to microbial and / or chemical degradation. Use of the container according to claim 8 for receiving substances from the series of foods for humans and animal feed, in each case in particular in pasty to small-sized form.

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