EP0512875A1

EP0512875A1 - Device for discharging a hot-melt adhesive

Info

Publication number: EP0512875A1
Application number: EP92400989A
Authority: EP
Inventors: Klaus Hubschen
Original assignee: Bostik GmbH; Bostik SA; Bostik Ltd; Bostik AB
Current assignee: Bostik GmbH; Bostik SA; Bostik Ltd; Bostik AB
Priority date: 1991-04-10
Filing date: 1992-04-09
Publication date: 1992-11-11
Also published as: DE9104381U1

Abstract

Device for receiving plasticised substances 1 and for discharging these substances after their plasticising, comprising a film tube 2 receiving the substances and closed at the upper end, which tube is connected at its lower end to a rigid bottom plate 3 with a preferably centrally arranged outlet opening 10 for the plasticised substances 1, and with a cylindrical supporting enclosure supporting the film tube on the outside.

The film tube (2) provided with an aluminium layer is accomodated, in a manner sealed off at its lower end, between an essentially cylindrical part (12) of the bottom plate (3) and a likewise essentially cylindrical outer ring (8), and the supporting enclosure (4) is not connected to the film tube and can be opened for introducing the film tube or removed for taking out the film tube.

Description

The invention relates to a device for receiving and discharging plasticisable substances, in particular a hot-melt adhesive.
U.S. Patent No 4,953,739 discloses a moisture-proof container of solid, moisture-curable composition comprising a reusable tubular body portion open at one end, a closure member provided with an outlet removably secured to said open end to close said tubular body portion, a slideable piston-head confining the composition in the body portion between the piston-head and the closure member, said piston-head having a rim projecting towards the closure member and in sliding, sealing engagement with the inner walls of said tubular body portion a bag of heat-resistant resilient foil open at one end and secured around said open end by said closure member, said bag being unattached to said tubular body portion, and solid, moisture-curable composition contained within the receptacle defined by said bag and said closure member.
This device suffers a number of disadvantages: the filling of the film tube takes place in the following steps : the film tube, sealed off at the bottom, is introduced while empty into a receptacle having a removable bottom; the free upper end of the film tube is turned over the edge of the cylindrical body of the receptacle ; the film tube is filled with the hot, molten substance ; a closure element is placed on top, which element also serves to seal off the free edge of the film tube ; the device is turned through 180° and stored for cooling; the removable bottom, which is now at the top, is removed and the content of the full tube is melted by a heating device and pressed out downwards by a ram. This procedure is time-consuming and has the result that, after removing the bottom, the imperviousness of the pack then depends only on the imperviousness of the ram and of the film, the actual receptacle on the other hand does not contribute any longer to the imperviousness. A subsequent separation of film tube and cylindrical body is not possible, so that for example an exchange of filled or partly emptied film tubes within the receptacle cannot be carried out, instead it is necessary to dispose of the entire receptacle with the film tube partly or completely compressed by the ram. The required imperviousness of the film tube is therefore not provided also because the passage of gas in both directions is possible through the tube itself.
The invention is based on the aim of avoiding these disadvantages and further developing a device for receiving and discharging plasticisable substances in such a way that, while achieving absolute imperviousness, an exchange of the film tube is possible without any difficulties.
This is achieved by a device for receiving plasticised substances, in particular a hot-melt adhesive, and for discharging these substances after their plasticising, comprising a film tube receiving the substances and closed at the upper end, which tube is connected at its lower end to a rigid bottom plate with a preferably centrally arranged outlet opening for the plasticised substances, this bottom plate being intended for fitting on a heating device in the case of meltable substances, and with a cylindrical supporting enclosure supporting the film tube on the outside, characterized in that the film tube (2) provided with an aluminium layer is accomodated, in a manner sealed off at its lower end, between an essentially cylindrical part (12) of the bottom plate (3) and a likewise essentially cylindrical outer ring (8), and in that the supporting enclosure (4) is not connected to the film tube and can be opened for introducing the film tube or removed for taking out the film tube.
Due to the design of the film itself and due to its connection with the bottom plate, absolute imperviousness is achieved, so that an escape of the molten substance upon actuation of the ram is ruled out. Since a connection of the film tube with the supporting enclosure is avoided, the supporting enclosure can be removed without any problem for taking out the film tube. This can take place, for example in one embodiment, by a supporting enclosure designed such that it can be swung open or, in another embodiment, by a tubular supporting enclosure which can be drawn off downwards or upwards. Furthermore, the filling of the film tube is simplified, since it dispenses with the turning over of the receptacle for cooling and precautions against deformation due to shrinkage upon cooling can be dispensed with. The absolute imperviousness of the receptacle for receiving the substances makes the device designed according to the invention particularly suitable for receiving and discharging reactive and/ or perishable substances.
Further advantageous designs of the device are the subject of the subclaims.
The invention is explained in more detail below with reference to an exemplary embodiment represented in the drawing, in which :

Fig. 1 shows the axial longitudinal section through the device;
Fig. 2 shows an enlarged representation, in section, the connection of the film with the bottom plate in the region marked in Fig. 1 by A;
Fig. 3 shows a cross-section through the supporting enclosure.

The film tube 2 encloses a substance 1 or a mixture of substances. This is preferably a hot-melt adhesive, which is pressed out downwards in the molten state and applied in the desired way to an adhesion surface. The content of the film tube 2 is usually about 5 to 20 liters.
The film tube 2 is sealed off at the top by a closure 11. The lower end of the film tube is connected, in a sealed-off manner, to a bottom plate 3. The bottom plate 3 has a preferably centrally arranged outlet opening 10 and, on its rim, a downwardly directed cylindrical part 12. Between the outlet opening 10 and the cylindrical part 12 there is space for an approximately annular heating device 5.
The film tube 2 is surrounded by a cylindrical supporting enclosure 4, the supporting enclosure 4 serves as cylinder for a ram 6, which is actuated by a ram rod 7 in the vertical direction. Upon a movement downwards, the adhesive, softened in the lower part of the film tube 2 by the heating device 5, is pressed out downwards through the outlet opening 10 and the adjoining central opening in the heating device 5.
The supporting enclosure 4 also serves the purpose of avoiding a bulging of the film tube 2 and consequently a possible tearing-open of the film tube.
The lower rim of the supporting enclosure 4 is about level with the bottom plate 3 and is not involved in the connection of the film tube 2 with the bottom plate 3. This permits an absolutely impervious connection, which is shown in detail in Fig. 2.
As Fig. 2 reveals, the lower end of the film tube 2 is clamped between the cylindrical part 12 of the bottom plate 3 and a likewise cylindrical outer ring 8. At the lower end, these parts are folded outwards at least once with the film lying in between, more preferably the cylindrical part is folded twice, thereby producing two regions 12a and 12b each folded by 180°, and the outer ring 8 is folded once, thereby forming a region 8a lying between the regions 12a and 12b. Additionally, the film tube may also be adhesively bonded or welded to the part 12 and the outer ring 8. As shown in Fig. 3, the supporting enclosure 4 is divided lengthwise into two cylinder halves, of which one is articulated to the other by a hinge 9. The cylinder half 4a, which can thus be swung open sideways, is shown in the swung-open state by dashed lines. During use of the supporting enclosure 4, the cylinder half 4a which can be swung open is locked to the other cylinder half on the side opposite the hinge 9, as is indicated by the dot-dashed line passing through the two abutting flanges.
Designing the supporting enclosure 4 such that it can be swung open achieves the effect that a lateral relative movement between supporting enclosure 4 and film tube 2 can take place. This permits an exchange of the film tube 2 and consequently also repeated renewed use of film tubes already partly compressed. In addition, due to the independence of the supporting enclosure 4 from the film tube 2, constant re-use of the supporting enclosure 4 is possible. After use, all that has to be disposed of is the compressed film tube 2 with the bottom plate 3 connected to it.
It is important that the hollow body formed by the film tube 2 and the bottom plate 3 is absolutely impervious, in order that neither can the substance escape from the receptacle nor, for example, can undesirable moisture enter the receptacle from outside, which can happen if the filled film tube remains in the applicator for a long time. This objective is also served by the special design of the film for the film tube 2. The film is namely a composite film with an aluminium layer, thereby achieving absolute water-vapour impermeability. Preferably, a polypropylene / aluminium / polystyrene film or a polyethylene / aluminium / polystyrene film is used.

Claims

Device for receiving plasticised substances, and for discharging these substances after their plasticising, comprising a film tube receiving the substances and closed at the upper end, which tube is connected at its lower end to a rigid bottom plate with an outlet opening for the plasticised substances, and with a cylindrical supporting enclosure supporting the film tube on the outside, characterized in that the film tube (2) provided with an aluminium layer is accomodated, in a manner sealed off at its lower end, between an essentially cylindrical part (12) of the bottom plate (3) and a likewise essentially cylindrical outer ring (8), and in that the supporting enclosure (4) is not connected to the film tube and can be opened for introducing the film tube or removed for taking out the film tube.
Device according to Claim 1, characterized in that the supporting enclosure (4) is divided lengthwise into two cylinder halves, of which one cylinder half (4a) can be swung open sideways.
Device according to Claim 1, characterized in that the supporting enclosure (4) is a tubular enclosure which can be drawn off upwards or downwards.
Device according to any of Claims 1 to 3, characterized in that the film tube consists of a polypropylene / aluminium / polystyrene film or a polyethylene / aluminium / polystyrene film.
Device according to any of Claims 1 to 4, characterized in that the cylindrical part (12) of the bottom plate (3) and the outer ring (8), which receive between them the lower end of the film tube (2), are folded outwards at least once.
Device according to Claim 5, characterized in that the cylindrical part (12) is folded twice by 180°, and the outer ring is folded once.
Device according to one of Claims 1 to 6, characterized in that the lower part of the film tube (2) is adhesively bonded or welded to the cylindrical part (12) and to the outer ring (8).
Device according to Claim 2, characterized in that the cylinder halves of the supporting enclosure (4) are connected to each other by means of a hinge (9).
Device according to one of Claims 1 to 8, characterized in that there is a receiving depression for the upper closure (11) of the film tube (2) in the centre of the underside of the ram (6).