EP0684190A2 - Packaging system for delicate bulk goods - Google Patents

Abstract

The packaging system has an outer container of sufficiently stiff material with a base surface area matching a conventional pallet. It contains adjacent layers of cube-shaped plastics containers each filled with a vol. of 10-120 l, to give four layers stacked over each other.

Description

The homopolymers and powdered copolymers of tetrafluoroethylene are extremely sensitive to pressure. For example, when filling, a certain bulk height must not be exceeded, otherwise the powder will cake together and error-free processing can no longer be guaranteed. Material squeezes caused by pressure can lead to defects in the molded articles produced therefrom, such as compacts or extrudates, which are unacceptable, particularly in the case of thin-walled products such as wire coatings or foils.

The polymers mentioned must also be protected against dust and moisture. As an essential prerequisite for ensuring the required qualities, the polymers of tetrafluoroethylene are manufactured and processed with the greatest possible exclusion of dirt particles.

The invention was therefore based on the object of providing a packaging system which ensures the maintenance of the named quality standard even when filling, transporting and removing the powder.

It is common today to fill powdered polymers of tetrafluoroethylene into round plastic or fiber drums. These drums must be so stable that they can carry the load of at least three stacked, filled drums per pallet container and up to four such pallet stacks in the warehouse or two pallet stacks during transport. In practice, however, it has been shown that even thick-walled constructions made of polyethylene and polypropylene at storage temperatures of up to about 60 _° C. can lead to a deformation of the lowest drums with such a stack weight. If a stack of this type collapses as a result, it can - in addition to high property damage - also endanger people. Another disadvantage of these round drums is that they fill the base of conventional pallets insufficiently, so that up to 25% of valuable transport volume remains unused.

A frame-container combination is known from US-A 5 275 289, each container being enclosed by a frame. The frames are designed such that they snap into stacks stacked above and below and into a pallet, preferably four of the stacks thus formed being arranged on a standard pallet. The container is made of cardboard. An outer wrapping made of cardboard or film can be provided for the transport. This system is unsuitable for powdery bulk goods.

• a) einen Außenbehälter aus hinreichend steifem Material, dessen Grundfläche im wesentlichen der einer üblichen Palette entspricht,
• b) der mit nebeneinander in Lagen angeordneten, im wesentlichen quaderförmigen Innenbehältern aus Kunststoff von je 10 bis 120 I Volumen befüllt ist, wobei diese Innenbehälter so ausgestaltet sind, daß bis zu vier Lagen übereinandergestapelt sein können.

The packaging system according to the invention overcomes the disadvantages mentioned and, with little effort, leads to packaging which meets the requirements and is generally suitable for sensitive bulk goods, especially for powders. The system according to the invention is characterized by

• a) an outer container made of sufficiently rigid material, the base of which essentially corresponds to that of a conventional pallet,
• b) which is filled with essentially parallelepiped-shaped inner containers made of plastic, each with a volume of 10 to 120 liters, which are arranged next to one another in layers, these inner containers being designed such that up to four layers can be stacked on top of one another.

Preferred embodiments of the invention are explained in more detail below.

The design and the material of the outer container depend on the intended use. For example, the outer container can more or less completely enclose the inner container and, for example, can also be designed in a lattice shape. Accordingly, the material can be metal, wood or plastic, or preferably cardboard. However, a completely closed form is preferred since it offers the inner container optimum protection.

Disposal is one aspect of the design of the outer container: if the container is to be used several times, it is expediently designed to be collapsible. In these cases the material will preferably be metal or plastic. If it is to be used essentially as disposable packaging, it is advisable to choose cardboard that is easy to dispose of.

A preferred embodiment of a cardboard outer container consists of an inner base part with a cover put over it, this so-called telescopic cover essentially enclosing the inner part.

In particular, if the outer container does not completely enclose the inner container, an additional covering by a film can be expedient, which offers additional protection against transport influences. If the material of the outer container is cardboard, a surface protection in the form of a varnish or a film cover can also be advantageous.

In any case, the outer container must reliably bear the load of the other outer containers stacked on top. A standard pallet is usually equipped with an outer container. The outer container can be placed loosely on the pallet or connected to it permanently or releasably. A firm connection, for example by means of screws, clips or gluing, can be considered if the pallet is to be reused as a packaging system. A detachable connection can, for example, be made of wires or strips in a manner known per se Metal or plastic or a film cover exist. Usually up to four of these units are stacked on top of each other.

The basic size of the outer container advantageously matches that of the pallet. A protrusion of the outer container over the edge of the pallet is undesirable, since otherwise damage to the outer container can occur. If the pallet protrudes, on the other hand, valuable transport volume is given away.

The pallet is preferably a standard pallet, for example with the standard dimensions 1000 x 1200 mm or 800 x 1200 mm. The pallet can be made of wood, cardboard, metal, plastic or a combination of these materials.

The shape of the inner container is essentially cuboid, which should also be understood to mean cuboids, cubes, but also conical configurations, since this embodiment can be easily stacked into one another in the empty state and thus takes up little volume before filling and during return transport.

The volume of the inner container is advantageously 20 to 100 l, since on the one hand smaller containers are less economical due to the use of materials and the volume required, and on the other hand larger containers with sensitive goods such as tetrafluoroethylene polymers can lead to clumping. Containers of 40 to 100 l, in particular 40 to 80 l, are particularly advantageous. Taking these volume ratios into account, the inner containers are designed in such a way that the volume of the outer container is optimally utilized. Usually four to six of these inner containers per layer and two to four layers are stacked one above the other in the outer container. The stiffness of the inner container is measured according to the number of layers and the resulting load on the filled containers. This is therefore considerably less than with the known plastic drums, which were previously stacked in up to four pallet stacks without an outer container.

The material of the inner container consists of conventional plastics such as polyolefins, in particular polymers of ethylene and propylene, polyvinyl chloride, polyamides and polyesters. Polyethylene and polypropylene are preferred.

The inner containers can be produced by conventional methods, advantageously by injection molding. They can have different configurations and can be equipped, for example, with carrying handles and stiffening ribs.

The inner container can be firmly closed with a lid, which can be designed in the usual way, for example connected to the container or loose. A snap lock is preferred.

From US-A 3 547 309 open stackable baskets for fruit and vegetables are known, the stiffening ribs of which allow both longitudinal and transverse stacking. They can be stably arranged on pallets by suitable stacking.

In contrast, the invention allows the inner container to be made relatively thin-walled, which not only results in considerable weight and material savings, but also allows the use of simpler and smaller machines and is therefore less energy-intensive with higher output. The resulting low weight of the inner container thus allows configurations of the entire packaging system with a considerable weight reduction or a favorable ratio of gross to net weight of the packaged goods, especially if the outer container is made of cardboard. This favorable relation is achieved according to the invention in that the outer packaging takes on the stacking load and the protection against transport influences to a considerable extent. In contrast, in small containers for household items and cosmetics, in which a plastic container is surrounded by a carton, this carton often only serves as an advertising medium and does not have the protective and support function for the absorption of high loads in one as in the present invention the pallet load weight in the range between 300 and 600 kg.

DE-A 2 711 632 relates to a cardboard box for transporting an odd number of containers which have a handle in the lid part. Through a cutout in the lid of the outer carton, the handle of the middle container can be gripped and thus the entire container can be easily transported by one person with one hand. The inner containers are preferably cuboidal liquid canisters.

A preferred embodiment of the invention is shown in Figures 1 and 2.

FIG. 1 shows three stacked packaging systems, each consisting of an outer container 1 and a pallet 2. The bottom of the three outer containers is shown in longitudinal section, 4 representing the wall or walls of the outer container 1, stacked in the three layers of inner containers 3 arranged one above the other are.

In Figure 1, the cut wall of the outer container is shown schematically only as a double line.

FIG. 2 shows a cross section through a packaging system according to the invention comprising an outer container 1, which is congruent with the underlying pallet 2 (not shown), and 4 being the wall of the outer container 1 poses. In this outer container 1, six conical inner containers 3 of square cross section are arranged per layer, the smaller base areas of the inner container 3 being shown in dashed lines.

Claims (10)

1. Packaging system for sensitive bulk goods, characterized by a) an outer container made of sufficiently rigid material, the base of which essentially corresponds to that of a conventional pallet, b) which is filled with juxtaposed, essentially cuboidal inner containers made of plastic, each with a volume of 10 to 120 liters, these inner containers being designed such that up to four layers can be stacked one above the other in the outer container. 2. System according to claim 1, characterized in that the outer container consists of cardboard and / or is preferably closed. 3. System according to claim 1 or 2, characterized in that the inner container is designed to hold a powder. 4. System according to claim 3, characterized in that the inner container has a lid with a snap lock. 5. System according to one or more of the preceding claims, characterized in that the inner container has a square cross section. 6. System according to one or more of the preceding claims, characterized in that the inner container is conical. 7. System according to one or more of the preceding claims, characterized in that two to four layers of inner containers are stacked in the outer container and preferably 300 to 600 kg load is contained in the outer container. 8. System according to one or more of the preceding claims, characterized in that up to four of the outer containers are stacked. 9. System according to claim 8, characterized in that the entire container has an outer protective cover. 10. System according to one or more of the preceding claims, characterized in that the inner container is filled with a polymer of tetrafluoroethylene.

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