Receptacles – Receptacle having flexible – removable inner liner – Paint receptacle
Reexamination Certificate
1998-01-28
2001-03-13
Sewell, Paul T. (Department: 3728)
Receptacles
Receptacle having flexible, removable inner liner
Paint receptacle
C220S062150, C220S062220, C220S023910, C220S023900
Reexamination Certificate
active
06199713
ABSTRACT:
The invention relates to a reusable container, in particular for environmentally harmful substances, according to the preamble of claim
1
.
Such a container, in particular in the form of a plastic bucket for paint, adhesive and the like, is known from German Offenlegungsschrift DE-A1-4,102,326.
After use, containers for environmentally harmful substances still contain a residue of the contents, while the outside is often covered with spilt residues of the environmentally harmful substances. These substances and containers soiled therewith are generally regarded as chemical waste, and must therefore be collected and disposed of separately. Under current legislation in this field, the percentage by weight of the environmentally harmful substances relative to the container is an important factor in determining whether or not the container is to be regarded as chemical waste.
In modern society the authorities are seeking to make the producer of environmentally harmful materials or products responsible for this disposal after use. In the case of e.g. a paint manufacturer it means that this manufacturer may be obliged to take back and collect used paint cans and buckets and to ensure environmentally acceptable processing thereof. In order to limit this quantity of waste for processing, it is in the interest of such a manufacturer only to dispose of the environmentally harmful substances, while the container body (e.g. cans or buckets) is available for reuse.
In the case of the bucket known from DE-A-4,102,326 a pull-off film is used as the protective coating on the inside and/or outside of the container body, said film being applied thereto with or without the use of an adhesive. After use, the protective coating with residues is pulled off the bucket. Ethylene vinyl acetate is mentioned as an example of a suitable film. Such buckets can be manufactured by heating the container body to a high temperature, e.g. 100° C., and then placing a preformed film of the protective coating therein under pressure. If both the container and the film are made of a thermoplastic material, the desired adhesion can be obtained by using pressure and heating.
A disadvantage of such a coating, which can be removed from the container body by pulling it away, is the risk that the coating will tear while it is being pulled away, even in the case of a relatively thick 0.2 mm film. If the container body is a complex shape, for example if it has a flanged top edge, this risk is high. It can mean that soiling of the container body itself can still occur, which is undesirable. This problem has already been recognized in DE-A-4,102,326, where it is proposed that the coating should be provided with a loop which is connected to a reinforcement strip placed in the coating, as a result of which the chance of tearing when the coating is being pulled away is counteracted. However, the disadvantages here are that the costs of the coating itself are increased, and its manufacture becomes more complicated and consequently more expensive.
A further disadvantage of this known container is that such a removal step of pulling the coating away is labour-intensive, certainly if the coating consists of several parts. Besides, mechanization of such a method is not easy to achieve. Finally, after the removal of the pull-off film, the container body will generally have to be degreased before a new peel-off coating can be applied.
WO-A-91/05714 discloses a container for Hazardous substances, in particular agrochemicals, comprising an outer shell made from compressed fibrous material, having an associated barrier of a polymeric material and an inner water soluble or water dispersible envelope for containing the contents. This envelope together with the contents can be tipped into water for further processing the contents.
EP-A-0 468 244 discloses a reusable plastic container, comprising a container body, of which the inside is provided with a plastic coating layer, which is not soluble in the intended contents of the container and which is soluble in an aqueous detergent solution. The difference in solublity of the coating material in the intended contents and the aqueous detergent solution is related to the difference of the acidity of the contents, respectively the detergent solution.
The object of the invention is to provide a reusable container to which the protective coating can be applied in a simple manner, and from which it can be removed and collected separately from the container body in a simple manner, and the costs of which are relatively low.
The features of the reusable container of the abovementioned type according to the invention are defined in the characterizing portion of claim
1
.
In the context of the invention ambient temperature should be understood as the usual temperature at which the contents of the container are stored, transported and processed. Solvent-resistant should be understood as meaning that the coating material is resistant to the contents of the container and to solvents which are normally used for processing the contents. The protective coating will not dissolve, react or otherwise deteriorate at the usual processing temperature under the influence of the contents or under the influence of means used for processing the contents. Raised temperature should be understood as meaning a temperature which is higher than the normal processing temperature.
One advantage of the container according to the invention is that the protective coating can be removed in a simple manner using a heated solvent, preferably water. Such removal can be carried out quickly and completely and is simple to automate. Examples of this are washing with a heated solvent, immersion in a bath of such a solvent or spraying with a solvent under pressure. The coating material removed, with residues, can be separated from the solvent using known purification techniques or, if the concentrations of film-forming material and residues in water are sufficiently low (lower than the permissible concentration limits for discharging into the sewer), the water can be discharged directly into the sewer. Such a coating can advantageously be applied very thinly (of the order of magnitude of micrometers) to the container body, while the desired physical properties of the protective coating can still be obtained. This means that the quantity of waste material for disposal, coming from the coating itself, can be kept small.
After use of the container, both the remainder of the contents and all residues of environmentally harmful substances which have been spilt or are otherwise adhering to the outside of the container body can be removed with the coating, so that the container body is completely clean and is thus suitable for reuse through the application of a new coating thereto and subsequent refilling of the container. Such removal of the protective coating is easily carried out by the manufacturer himself, who takes back the containers from the user after use. After removal of the protective coating, it is possible to apply a simple cleaning operation, e.g. washing and drying, if such cleaning is considered necessary.
The demands to be made of the coating material include chemical resistance, for example to the environmentally harmful substances, as already stated above, and sufficient strength to prevent damage during use. Such damage can occur if, for example, the contents of the container have to be stirred or mixed in some other way before being processed.
Preferred materials suitable for use as protective coating materials according to the present invention include acrylic-based polymers or resins.
It is also advantageous for the outer coating to be transparent. This makes it possible to print the outside of the container body once, for example with a brand name and/or data concerning the contents of the container, without such data having to be applied to the outer coating. Since this coating part is transparent, the outside of the container body, and consequently these data, always remain visible.
A material which is particularly
Arnold Troy
Henkel Nederland B.V.
Ostrolenk Faber Gerb & Soffen, LLP
Sewell Paul T.
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