DE4203761A1 - Lining open container with thin or thick plastic film - by briefly heating outer side of film placed over container and applying pressure impulse to press film on to container surface - Google Patents

Abstract

Containers are lined and, in particular, reusable containers receive a soluble lining. Material sheet placed over or into the container, is softened, and pressed on to the inner face of the container by a pressure impulse; alternatively the container is a sheet metal bucket and/or the inner covering is pressed on the side away from the container to soften and/or thick sheets of material. ADVANTAGE - Thin or even relatively thick plastic films can be applied. Heating the film requires only very few secs. Pressure required is very low and a pressure impulse can use steam or air. In an example white metal bucket (1) is stood on the base (6) with its foam rubber top (7) and vacuum bores (8). Film (2) is placed over the top of the bucket (1) and a top tool (3) is lowered. Steam at 0.5 bar and 150 deg.C is applied to soften the film (20 which sags accordingly. Pressure in the head (3) is raised e.g. very rapidly, the bucket (1) is pressed down on the foam (7), and the air can be exhausted from inside the bucket (1), as the film (2) is pressed into it.

Description

The invention relates to a method for lining the inside of buckets, ins especially for the production of removable inner linings from Mehrwegbe patented conditions. ., Patent application P 41 02 326.

Based on the consideration, the packaging effort by creating a The proposal for a patent includes reducing reusable containers. ., Patent application P 41 02 326 the technical teaching, the bucket with a To provide inner lining. The inner lining should be made of plastic stand, which is placed in the bucket.

The outer surfaces of art are slightly plasticized fabric lining with the bucket.

The invention has for its object the concept of the inner lining of containers.

This is done on the one hand by application to metal containers, in particular buckets made of sheet metal. Such buckets usually have a capacity of up to 40 liters capital. It turns out that even with metallic containers a certain Adhesive effect is provided, provided the inner jacket of the containers is not provided with a release agent or with a release agent acting dirt.

The second is a further development of the patent. . , Patent application P 41 02 326 achieved in that not only foils of thin material thickness, but also relatively thick foils are used. The adhesive effect can be considerably reduced with thick foils. That means that for thick foils adhesive effects are already sufficient are insufficient for thinner films. The measure "sufficient" is due to the mechanical load acting on the inner lining. In the As a rule, the maximum degree of exposure to agitators is caused by where mixtures are generated or homogenized. The same applies for stirring other substances.  

Optionally, the foils can also be chosen so thick that they are according to their Deformation as inner lining even without adhesive effect the occurring me withstand the stress of the Chinese. As a rule, the necessary Material costs conflict with this, since the advantageous adhesive effect also without Additives or adhesives due to the plasticity of the plastic material and the contact pressure.

While in the patent. . , Patent application 41 02 326, still to be introduced the film or a blank is proposed, the film or the shape Another person sees warming at the contact surface with the container Alternative before, heat the film on the opposite side and thereby plasticizing.

The heating necessary for plasticizing takes a few seconds. The out sufficient warming is often evident from the fact that a horizontal over the Container held film loses the surface tension and down sags. In this heating state, a pressure surge can cause a Sudden deformation of the film leads to the desired inner lining. Steam can be used to heat the film. It is suitable Steam at 120-200 degrees Celsius temperature and 0.5-3 bar pressure. With this Pressure, especially in the range of 3 bar, is also without additional pressure given a deformation to an inner lining.

The pressure surge can therefore be omitted if there is sufficient pressure.

The pressure surge is carried out either with steam or air.

It is advantageous to apply the deformation of the film by applying a vacuum to support the space between the film and the inner casing. The air in the intermediate space then does not have to go any way seek to escape and build up no deformation resistance. The vacuum can be created by piercing the bottom of the container. It it is convenient to place the penetration openings on the edge of the container bottom. Furthermore, relatively small outlet openings for applying the vacuum are made reaching. For example, three needles may be sufficient. The needles are withdrawn before the container lining is formed or something specifically introduced that they do not protrude beyond the bottom of the container.  

Then the needles can remain in the container from the bottom if they are at the same time suitable openings for extracting air from the space between the film and the inner wall of the container. In this case so tubular needles, cannulas used.

After removing the needles, there is a small opening width remaining holes and due to the existing inner lining of the container no risk of leakage.

It can be a device with very ge for introducing the openings or needles with little effort. A device of this type is suitable Foam base in which the needles are sunk. The one described above Pressurizing the container compresses the foam base and pushed the needles through the bottom of the container.

The foils can be used as material webs or cuts. By prefabricated moldings that are already largely or in the container even partially protrude, the deformation process to a small extent Be limited.

Two exemplary embodiments of the invention are shown in the drawing.

Fig. 1 shows a device which consists of a foot 6 with a foam head 7 and evacuation lances or evacuation cannulas 8 and an upper part 3 .

The upper part 3 can be raised and lowered. A bucket 1 made of sheet metal (white metal) and a film web 2 are arranged between the upper part 3 and the base 6 .

Lowering the head 3 creates a closing connection with the bucket 1 and the intermediate film 2 .

After the head 3 has been lowered, the film 2 is subjected to superheated steam in the region of the surface covered by the head 3 . The superheated steam has a temperature of 150 degrees Celsius and, in the exemplary embodiment, 0.5 bar overpressure with respect to the surrounding atmosphere.

The pressure can fluctuate up to 3 bar. The film 2 is plasticized by the superheated steam. Depending on the thickness of the film, the plasticization takes a few seconds to 1 minute. With increasing plasticization, the film 2 bulges in the clamped area. As soon as a bulge is clearly recognizable, the pressure in the head 3 is increased. This happens suddenly in the exemplary embodiment. Due to the pressure force, the bucket 2 is pressed down. Optionally, the downward movement can also be caused briefly beforehand by the head 3 . During the downward movement, the plastic foam part 7 is compressed and the evacuation cannulae 8 penetrate into the sheet metal base.

After the evacuation cannulas 8 have penetrated, the space between the bucket 1 and the film 2 can be evacuated or the enclosed air can be given the opportunity to escape when the film 2 is deformed.

Excessive penetration of the evacuation cannulas 8 is preferably prevented by a stop which engages around the bucket rim in a manner not shown or is sunk in the plastic foam part 7 and in this way limits the bucket path 1 downwards.

The evacuation cannulas 8 are arranged in such a way that the passage openings are formed at the edge of the bucket.

In another embodiment, pre-perforated buckets are used, so that piercing is no longer required, but rather only the evacuation cannulae 8 are attached. If necessary, the evacuation cannulas 8 are also dispensed with, so that the trapped air escapes from the head 3 only because of the deformation pressure.

In a further exemplary embodiment, the sudden deformation process after plasticizing the film 2 is generated with the aid of compressed air additionally released in the head 3 .

Fig. 2 shows an embodiment with a pre-shaped body 10 in place of the film 2. The prefabricated molded body 10 has an edge 11 with which it is clamped between the head 3 and the bucket 1 .

The molded body 10 already largely corresponds to the profile of the bucket 1 , so that after the molded body 10 has softened, only a slight deformation is required in order to bring the molded body 10 into contact with the inner surface of the bucket 1 .

In the exemplary embodiment, the thicknesses of the film 2 or of the molded body 10 are selected such that the adhesive forces arising after the plasticization and pressing of the plastic onto the inner wall of the bucket 1 , with the associated adhesive effect, the dimensional stability of the resulting inner lining of the bucket 1 is essential carry along.

The film 2 and the molded body 10 consist of polyethylene, which behaves neutrally to numerous substances, in particular the substances provided here for filling the bucket, and at the same time is suitable for developing an adhesive effect.

Claims (9)

1. Process for lining the inside of containers, in particular for producing a removable inner lining of reusable containers according to the patent. . . , Patent application P 41 02 326, characterized in that a material web ( 2 ) or a material blank ( 11 ) is brought over or into the respective container ( 1 ), plasticized and brought to bear against the inside wall of the container by means of a pressure surge and / or that the container is formed by a metal bucket and / or loading of the inner lining on the side facing away from the container for plasticization and / or by thick-walled material webs or material blanks. 2. The method according to claim 1, characterized in that the blank ( 10 ) is a molding. 3. The method according to claim 1 or 2, characterized by a plasticization with Superheated steam. 4. The method according to one or more of claims 1-3, characterized by a pressure surge with steam or air. 5. The method according to one or more of claims 1-4, characterized by a simultaneous evacuation of the space between the inner wall of the container and the blank ( 10 ) or material web ( 2 ). 6. The method according to claim 5, characterized by the use of Eva kuierungskanulen ( 8 ). 7. The method according to claim 6, characterized in that the evacuation cannulas ( 8 ) penetrate the container wall. 8. The method according to claim 7, characterized by a perforation in the edge area of the container bottom. 9. The method according to one or more of claims 6-8, characterized by a resilient support (7), in which the evacuation cannulas (8) are recessed, wherein the container (1) against the support (7) and the cannula (8) is pressed.