Patent Application
20230115825
This patent application claims the benefit under 35 U.S.C. 119 to German Utility Model Application No. DE 20 2021 003 146.4, filed on Oct. 7, 2021, the entirety of which is incorporated herein by reference.
The present invention relates to a ball can which can be particularly well recycled.
Ball cans for, for example, tennis balls or balls for padel tennis have been known for a long time. Typically, these balls are pressure packed, i.e., in order to avoid early pressure loss of the balls, which have a higher pressure inside than the atmospheric pressure, the balls are also stored in the packaging under higher pressure. The ball cans are typically made of a plastic material and have a breakaway aluminum closure. After the latter has been broken away to open the can for the first time, the can typically can be closed with a plastic cap or the like. Ball cans often are configured to be transparent, in order that the balls inside can be easily identified, and/or printed or provided with a band. However, this is disadvantageous in view of the recyclability of the individual can materials and/or components.
It is therefore an object of the present invention to provide a ball can which can be particularly well recycled or reprocessed. This object is achieved with a ball can according to claim 1. Preferred embodiments of the ball can according to the invention are described in the dependent claims.
Accordingly, the present invention is directed to a ball can comprising a can base and a, preferably cylindrical, can wall, wherein at least in one or more sections the can wall comprises a roughened surface and wherein, for marking the can, a layer of another material is applied to the can wall such that the surface roughened at least in one or more sections is at least partially exposed.
The ball can is preferably a ball can for tennis balls or balls for padel tennis. In principle, however, the ball can according to the invention is also suitable for other sports balls, in particular for other pressure-packed balls.
Although it is advantageous for the can wall to be circular cylindrical in view of the spherical shape of most balls, this is obviously not necessary. Rather, the can wall may also form a cylinder having a different base area, such as a triangular or square base area. The shape of the can wall can also deviate from a cylinder in the mathematical sense, for example in that the can wall is slightly corrugated, comprises indentations and/or bulges and/or deviates from the cylindrical shape in the region of the can base.
The ball can according to the invention is optimized for common recycling processes for several reasons. For example, it has turned out that the automatic recognition of different plastic materials during the recycling process can be carried out in a less error-prone manner if the corresponding material is roughened. Accordingly, the roughened surface of the can wall facilitates material recognition during the recycling process. For this purpose, it is further advantageous that the surface roughened at least in one or more sections is at least partially exposed, since a correct determination of the can material underneath the layer of the other material can be problematic.
Against this background, it is preferred that the can wall comprises an outer surface and that the layer of the other material covers at most 80%, more preferably at most 70%, even more preferably at most 60%, even more preferably at most 50% and particularly preferably at most 40% of this outer surface. Thus, a correspondingly large area is provided for correct material recognition.
The layer of another material for marking the can may be a sticker covering only a portion of the outer circumference of the can wall. However, it is preferred that the can wall comprises an outer circumference and that the layer of the other material extends around at least 50%, more preferably around at least 65%, even more preferably around at least 80% and particularly preferably around at least 90% of this outer circumference. However, in view of easy manufacturability of the ball can according to the invention and the simplest possible separation of the can from the layer of the other material, it is particularly preferred that the layer of the other material comprises a band or the like extending around the entire outer circumference of the ball can. The two ends of the band may be arranged to overlap one another in the longitudinal direction.
Preferably, the layer of the other material is adhered to the can wall, the adhesion preferably not being over the entire surface. Preferably, the adhesive area measures at most 3,000 mm2, more preferably at most 2,500 mm2, even more preferably at most 2,000 mm2, even more preferably at most 1,000 mm2 and particularly preferably at most 500 mm2. In the case of a band, for example, only an adhesive strip can be provided, which extends over the entire width of the band. Particularly preferably, only punctiform adhesion is effected at one or a few points. Minimizing the adhesive area facilitates the removal operation during the recycling process.
Against this background, it is particularly preferred that the adhesive is water-soluble so that a corresponding material separation can be carried out in a particularly environmentally friendly manner. Preferably, the adhesive comprises one or a combination of the following materials: hot-melt adhesive (hot glue) based on ethylene vinyl acetate (EVA) or on polyethylene.
It is further preferred that the material of the layer of the other material has another density than the density of the ball can material, wherein the difference in density is preferably at least 0.02 g/cm3, more preferably at least 0.05 g/cm3 and particularly preferably at least 0.1 g/cm3. Due to the different density, the layer of the other material can be relatively easily and automatically separated from the ball can material after detachment so that the latter is not contaminated during shredding.
The layer of the other material preferably comprises one or a combination of the following materials: oriented polypropylene (OPP), PET (polyethylene terephthalate), pearlescent BOPP films (BOPP=biaxially stretched polypropylene), coated paper, bio-polylactide (PLA), e.g. from corn starch.
The ball can, i.e. in particular the can base and the cylindrical can wall, preferably comprises one or a combination of the following materials: polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, aluminum, tin paper, wood, bamboo, coated paper.
In view of better processing during the recycling process, it is further preferred that the weight of the ball can, i.e. in particular of the can base and the cylindrical can wall without the lid and the layer of another material, is at most 40 g, more preferably at most 38 g and particularly preferably at most 37 g.
The roughness of the ball can wall can be characterized by one or more of the following parameters: Ra at least 0.5 μm, Ra at least 1.0 μm, Ra at least 1.5 μm, Ra at least 2.0 μm, Rz at least 2.0 μm, Rz at least 4.0 μm, Rz at least 6.0 μm, Rz at least 8.0 μm, Rz at least 10.0 μm.
The parameters Ra and Rz can be determined, for example, with the Surface Roughness Tester TR200 from the company Ovovo.
The ball can may further comprise a lid, wherein the material of the lid is preferably different from the material of the can and/or from the material of the layer of the other material. Also, the density differences between the layer of the other material and the can lid material and/or between the ball can material and the can lid material are preferably at least 0.02 g/cm3, more preferably at least 0.05 g/cm3, and particularly preferably at least 0.1 g/cm3.
Preferably, the roughened surface of the can wall is translucent, but still sufficiently transparent that it can be seen with the naked eye whether there is a ball in the ball can.
Preferably, apart from the can lid and the layer of the other material, the ball can consists of only one material, which is particularly advantageous in terms of recyclability. Against this background, it is also preferred that the ball can is not printed and that all marking is on the layer of the other material, since printing ink can also deteriorate the purity degree of the recycled material and/or render the reprocessing process complicated and expensive. For the same reasons, it is preferred that the ball can, i.e. in particular the can base and the can wall, is not inked.
In the following, a preferred embodiment of a ball can according to the invention is described in more detail with reference to
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2021 003 146.4 | Oct 2021 | DE | national |
