DE2528598A1 - CONTAINER MADE OF CREEPABLE PLASTIC MATERIAL - Google Patents

Description

PATENT LAWYERS
DR. CLAUS REINLmNDER DIPL.-ING. ! CLAUS BERNHARDT

D-8 Munich 60 Orthstrasse 12 Telephone 832024/5 2528598

Telex 5212744 Telegrams Interpatent

PlO P4 D

PLASTONA (John Waddington) Limited »Leeds, Great Britain

Containers made from creepable plastic material Priority: June 29, 1974 - Great Britain - 28977/74

The invention relates to containers which are suitable for carbonated beverages and preferably also contain those and which are made of thin-walled plastic.

Much research and development has been made to manufacture thermoplastic containers that do this are suitable for containing carbonated beverages, such as beer or soft drinks. So far there are Drinks in large quantities in metal cans with flanged End caps, some of which have ring pull opening devices, or are stored in glass bottles with screw caps or crown locks are closed.

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Metal cans and glass bottles have made the market for carbonated Drinks have been dominated to a large extent, mainly because they have sufficient firmness to hold the to withstand the superatmospheric pressures prevailing in containers filled with carbonated beverages and are locked. These pressures still increase depending on the temperature of the environment in which the container is located be stored. In general, the internal pressure that is generated in the containers, the higher the higher the Ambient temperature. Another reason for using metal and glass for such beverages is that 'These materials are very impermeable to moisture and air, and carbonated drinks that come in containers made of glass or metal can be stored for a long time.

However, the use of glass and metal for such containers creates several disadvantages. First of all, it can be assumed that the cost of these materials will rise faster than that of plastic in the future, and from the standpoint of energy saving it must be taken into account that a lot of energy is required to manufacture such containers, compared with the energy required to produce thermoformed plastic containers. Glass bottles have the obvious disadvantage of being dangerous, and that is true, albeit perhaps to a lesser extent Dimensions, for metal cans. So there is a real need for containers made of plastic material that are suitable for contain carbonated beverages.

When a carbonated beverage is stored in a plastic container, the plastic material "creeps" over time and internal pressure, and stretches slightly. This inevitably has the effect that the base or The base plate of the container warps unevenly, so that if the container is free before the "creep" begins,

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he then tips over what is known as a "rocker". That is, the stability of the container for free standing is seriously deteriorated.

The invention addresses this problem and it is its object to provide a novel form of base or base plate for to provide a plastic container that creeps when filled with carbonated beverage and sealed so that he does not become a "rocker" despite the creep. The invention is mainly locked with Containers for carbonated drinks, but is not entirely limited to these, as it goes without saying the novel base according to the invention can also be used in containers containing other products, which can cause higher internal pressure under special circumstances.

If the containers are specifically designed for carbonated beverages, then they can be constructed to accommodate them form a gas barrier for the contents of the container so that there is a noticeable loss of carbonic acid gas over a storage period is prevented after the container is closed. In view of this, the plastic material can be in laminate form be constructed or coated inside, so that an outer housing and an inner lining are formed, the forms the gas barrier, with the outer housing providing more of the strength of the container. The container can consist of a single thickness of plastic, of course.

The container can consist of an outer housing made of polystyrene, polypropylene, Polyethylene or the like. Exist and the lining material can, for example, from high-barrier Acrylic material, polyvinyl chloride or a copolymer of the same or a coating such as SARAN.

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Containers of the general type mentioned are known and they are generally supplied with a carbonated one Filled drink and closed with a lid. When such a container is initially closed, the drink is usually cool and therefore tends to keep the carbonated gas in solution. When the temperature of the beverage rises to ambient temperature after the container is closed, the pressure within the rises Container in that part of the carbonic acid gas from Drink is released. The plastic material container creeps, as explained above, and such Creeping is not a problem, unless a "rocker" occurs, but of course the container should burst be avoided.

It is already known to build a thin-walled plastic container so that it has the opportunity to be under one To be able to expand to a limited extent after closing, and the increase in the gas pressure inside the container known proposal is that the container is provided with a bottom, which is a spherically concave Has area that can flip outward in a spherically convex shape when the pressure inside the container enters exceeds the specified maximum. This possibility of increasing the effective volume of the container has the advantage of to reduce the internal pressure and thus reduce the risk of the container subsequently exploding, however of course a "rocker" arises, which is undesirable.

The invention is intended to provide a thermoformed container be made joinable, which has a base shape designed to withstand higher internal pressures can, without fundamentally changing the shape, as happens with the known containers.

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According to a first aspect of the invention, a tightly closed, thin-walled plastic container is available which creeps by high internal pressure, and which has a wall and a base, and this one According to the invention, the container is characterized in that the base plate is defined by a central part which is surrounded by spaced feet which the container is free, and bracket parts, which radiate from the central part, extend between the feet and curve upwards to the wall, these bracket parts hinder the creeping movement of the central part, so that this is prevented from protruding through the plane containing the surfaces of the feet on which the container stands freely.

The temple parts and the central part of the base preferably lie on a spherical surface and define it partly.

With such a structure, the base's resistance to creep is hemispherical or partial spherical modulus, which means higher strength. The feet give the base the stability it needs to stand freely.

According to a specific embodiment of the invention, each foot generally has a kidney or bean-shaped cross-section and curves around the central area. The inner edge of each foot preferably has a central recess. These Recess on the inside of each foot provides additional resistance for the whole base that is underneath high internal pressure in the container is spherical. Furthermore, the strength of the base is maintained.

According to another embodiment, the feet can each have a generally triangular cross-section and extend from the central part expand outwards, whereby the opposite

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lying sides of adjacent feet are essentially flat and close together, so that the temple parts are small Have width.

The invention also makes a container available prior to filling and sealing.

The closure can be done by means of a cap made of metal or plastic, and the top of the container is shaped accordingly for this purpose.

The invention is to be explained in more detail with reference to exemplary embodiments shown in the drawing; show it:

1 shows a perspective view of a container according to an embodiment of the invention before it is closed;

Flg. Figure 2 is a side view of the container of Figure 1; 3 shows a bottom view of the container according to FIGS. 1 and 2; Fig. 4 and

5 shows sections along the lines Y-Y and Z-Z in FIG. 3;

6 shows a section of the upper part of the container corresponding to FIG. 4 after a closure lid has been applied;

Fig. 7, 8

and FIG. 9 representations corresponding to FIGS. 1, 2 and 3 of a second embodiment of the invention; and

Fig. 10

and 11 sections along the lines A-A and B-B in FIG. 9.

The container shown in Figures 1 to 6 is a thin-walled, Thermoformed cup 10 made of plastic with a generally frustoconical wall 12, on the

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Bottom a base 14 according to an embodiment of the invention is provided, and in the top there is a deinterleaving ring 16. The deinterleaving ring is closer shown in Fig. 4, it can be seen at the upper end of this ring is a flat, outwardly protruding Flange 18. This flange 10 is used to create an equivalent flange of a metal cover 20 in the one shown in FIG shown way. The lid is double crimped onto the flange 18 for an effective gas-tight seal To form a seal, and the metal lid, which may be of conventional shape, is provided with an opening ring device 22, to have access to the contents of the container, in this case carbonated drink.

The container described so far is known, apart from the special basic construction shown in the drawing and forms the novel feature of this embodiment of the invention.

In particular in Figures 1 and 3 and 5 it can be seen that the base 14 is based on the principle of a semi-spherical or partially spherical shape, which is best seen at 30 in FIG. 5. The base would consist entirely of this semi or part spherical shape 30, if not three of the same Angled feet 32 would be provided by the spherical shape 30 protrude downward, and form a means with which the container can stand free. the Feet 32 are arranged around a pitch circle so that they leave a central part 34 free, which is on the spherical Shape lies, and radial bracket parts 36, which also lie on this spherical shape and extend from the central part 34 extend from and are integral therewith; these parts curve upwards towards the lower part of the main wall 12.

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The feet 32 each have a generally flat floor 38, and these floors lie in a common transverse plane relative to the container axis, and each foot is generally kidney or bean-shaped in cross-section, as best can be seen in FIG. 3. Because the feet protrude from a spherical module, the outer walls of the feet are longer than the interior walls. The outer walls 40 lie essentially on a truncated cone surface with the same cone angle like the wall 12, while in the middle of each of the inner walls 42 there is a recess 44 into which the Central part extends in and which has the effect of increasing the area of the central, partially spherical area 34. The effect of these recesses 44 on the inner walls of the feet is to provide additional strength in this To achieve critical area and a resistance to deflection of the central part, as will be explained.

When using the container, it is filled with carbonated drink and the top is closed, as shown in FIG. As the internal pressure in the container increases over time, the plastic material "creeps" of the container. However, although some creep occurs in the base 14, the base practically changes their shape does not, and as a result of such creep, the base is not so deformed that the container becomes unstable will. As can be seen from Fig. 5, the surfaces of the feet 38, on which the container stands freely, lie in an A designated level before the plastic material of the container creeps. During the crawl, the middle part moves down to the position shown in broken lines in FIG. 5, and the insides of the feet 38 roll inwards and downwards. The formation of these recesses 44 resists this inward and downward rolling of the insides of the feet so that the basic shape of the base is retained. The function of the bracket parts 36 is important because this

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Temple parts resist the downward movement of the middle part 34 and prevent it from passing through the new level B. to wander through, in which the supporting surfaces of the feet are after crawling. The container is therefore behind as before free on the feet, because the central part 34 remains alone, where the level B contains the footrest surfaces. The amount of creep that has taken place in the base, can be viewed as the distance between planes A and B according to FIG. The dimensions of the container will be Due to the crawling, it is somewhat larger overall, but this enlargement is nowhere as great as in the base, namely This is because the resistance of the wall to annular stresses is greater than the resistance of the Feet 38 against stresses running in the form of a ring. In cross-section, the feet 38 are designed to be so close spherical as possible in order to obtain an optimal resistance against stresses running in a ring shape. The special shape chosen for the base gives it extreme strength, combined with providence a possibility that the container can stand freely on its base.

It can be seen that the shape of the base in the described embodiment is basically the same as after creeping before crawling. It is not necessary that this be the case because the central part, at least before crawling, may be inwardly concave, inwardly conical, or outwardly conical, provided that after creeping the central portion remains at a height which is higher than the supporting surfaces of the feet (plane B in Fig. 5). So if the central part is initially directed inwards, it can turn outwards as well as the internal pressure in the container increases crawl, however, he shouldn't be able to get below level B when all of the base crawl is taken into account.

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In the embodiment of the invention according to FIGS. 7 to 11, the container is basically constructed similarly to the container according to FIGS. 1 to 6 and is also used in this way. The exception is that the wall 12A extends to the top flange 18A and no deinterleaving ring 16 is provided, and also that the base has six feet 32A which are generally rectangular in cross-section and expand radially outward as shown in FIG 9 shown. In the inner region, the feet 32A gradually merge into the central part 34A, while in the outer region 40A the feet lie on a frustoconical surface with the same conical angle as the wall 12A. The opposing surfaces of adjacent feet are spaced significantly less than in the embodiment of Figures 1-6 and are generally flat to define narrow temple portions 36A and narrow radial gaps 37 between adjacent feet. All corners and edges of the feet are rounded for maximum resistance to creep and, as in the previous embodiment, the creep of the container base under internal pressure is such that the central portion 34A does not protrude above the plane on which the container is exposed stands.

It can be seen that containers with a basic construction according to the invention are in principle suitable for applications in which overpressure develops within the container during use, the basic construction can, however, if desired can also be used in applications where this overpressure is generated on request, for example by heating the contents of the container while they are still in the container.

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The container can be made of any suitable plastic, albeit if specifically designed for Carbonated drinks are intended, it is best to use a plastic material or a combination of Select plastic materials that will give the best gas barrier, provided that this is compatible with that little or no monomer from the plastic material in the drink is dispensed. In particular, the acrylonitriles are especially suitable for these containers, above all Nitrile polymers based on acrylonitriles. The polyester plastics are also extremely suitable, as do some of the polyolefins, particularly polyethylene and polypropylene. The polypropylene and polyethylene are best used when it is possible to provide an internal layer for the container as a gas barrier, for example a thin layer of nitrile polymer,

It should also be noted that while the container is preferably thermoformed, it is possible to form it in other ways, such as injection molding, although this process can currently prove to be more costly than thermoforming.

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Claims (12)

Claims Sealed, thin-walled container made of plastic which creeps under higher internal pressure and has a wall and a base plate, characterized in that the base plate is defined by a central part which is surrounded by spaced feet on which the container stands free and bracket parts which radiate from the central part, extend between the feet and curve upwards towards the wall, these stirrup parts hindering the creeping movement of the central part, so that it is prevented by the plane containing the surfaces of the feet on which the container stands free to preside. 2. A container according to claim 1, characterized in that each foot is generally kidney or bean-shaped in cross-section and is curved about the central region. 3. Container according to claim 2, characterized in that the inner surface of each foot has a central recess into which the central part extends. 4. Container according to claim 1, 2 or 3, characterized in that three identical feet are provided which are arranged at the same angles. 5. A container according to claim 1, characterized in that the feet are generally triangular in cross-section, flaring outwardly from the central portion and the opposing sides of adjacent feet are substantially flat and close together. ... / A2 509883/0392 -AT- 6. Container according to one of claims 1 to 5, characterized in that the container is thermoformed. 7. Container according to one of claims 1 to 6, characterized in that the container by means of a metal lid or plastic with a device for relief
of opening is tightly closed. 8. Container according to one of claims 1 to 7, characterized in that the bracket parts and the central part of the
Base plate lie on a spherical surface and
define part of the same. 9. Container according to one of claims 1 to 8, characterized in that it consists of acrylonitrile. 10. Container according to one of claims 1 to 8, characterized in that it consists of polyester. 11. Container according to one of claims 1 to 9, characterized in that the container is made of polystyrene and has an inner layer made of acrylonitrile, which acts as a gas barrier
works. 12. Container according to one of claims 1 to 8, characterized in that it consists of polypropylene. 509883/0392 Blank page