EP0619777A1

EP0619777A1 - Plastic foam molded body, process and device for producing the same

Info

Publication number: EP0619777A1
Application number: EP93923488A
Authority: EP
Inventors: Joachim Teubert
Original assignee: TEUBERT MASCHINENBAU GmbH
Current assignee: TEUBERT MASCHINENBAU GmbH
Priority date: 1992-11-04
Filing date: 1993-10-18
Publication date: 1994-10-19
Also published as: DE4237239A1; WO1994009982A1

Abstract

Un corps moulé en mousse alvéolaire, se présentant notamment sous forme de plaque en matériau alvéolaire (2), réalisé dans un matériau alvéolaire granulé préexpansé, se caractérise en ce qu'il comprend un noyau (4) réalisé dans un matériau alvéolaire usagé recyclé et comportant, sur au moins un côté, une couche de protection (6) réalisée dans un matériau alvéolaire frais, le cas échéant différent. Selon un procédé de fabrication d'un corps moulé en mousse alvéolaire (2) de ce type, il est prévu que, dans un premier temps, le noyau (4) soit réalisé de manière usuelle à partir d'un matériau alvéolaire broyé, recyclé, introduit dans la cavité d'un moule (12); que la cavité du moule soit ensuite élargie conformément au contour de l'enveloppe (6) tout en maintenant le noyau (4) dans une position définitive par rapport à la cavité élargie du moule; que ladite cavité élargie soit remplie d'un matériau alvéolaire brut, granulaire, frais, préécumé et que ce dernier soit en outre durci de manière usuelle, après quoi le corps moulé fini en mousse alvéolaire (2) est démoulé. Un dispositif (10) de mise en oeuvre dudit procédé peut comporter outre deux parois de moulage (14, 16) déplaçables l'une par rapport à l'autre, d'autres parois de moulage (18, 20) pouvant être entrées et sorties de manière coulissante, placées à la périphérie des premières parois de moulage et ayant une épaisseur correspondant à celle de la paroi de la couche de protection (6) à cet endroit là. Le dispositif peut également comprendre des organes de retenue (66) en forme de tiges qui peuvent être sortis des premières parois de moulage (14, 16) et peuvent pénétrer dans le noyau (4) moulé au début, ainsi que des organes de positionnement (64) se présentant sous forme de plaques, utilisés pour positionner latéralement le noyau par rapport auxdites parois de moulage.A molded body of cellular foam, in particular in the form of a plate of cellular material (2), made of a pre-expanded granulated cellular material, is characterized in that it comprises a core (4) made of a recycled used cellular material and comprising, on at least one side, a protective layer (6) made of a fresh cellular material, different if necessary. According to a method of manufacturing a molded alveolar foam body (2) of this type, provision is made that, initially, the core (4) is produced in the usual way from a crushed alveolar material, recycled , introduced into the cavity of a mold (12); that the mold cavity is then enlarged in accordance with the contour of the casing (6) while maintaining the core (4) in a final position with respect to the enlarged mold cavity; that said widened cavity is filled with a raw, granular, fresh, pre-skimmed cellular material and that the latter is further hardened in the usual way, after which the finished cellular foam molded body (2) is demoulded. A device (10) for implementing said method may comprise, in addition to two molding walls (14, 16) which can be moved relative to each other, other molding walls (18, 20) which can be entered and in a sliding manner, placed at the periphery of the first molding walls and having a thickness corresponding to that of the wall of the protective layer (6) at this place. The device can also comprise retaining members (66) in the form of rods which can be taken out of the first molding walls (14, 16) and can penetrate into the core (4) molded at the start, as well as positioning members ( 64) in the form of plates, used to position the core laterally relative to said molding walls.

Description

Foam molded article, process for its production and device for carrying out the process.

The invention relates to a foam molded body, in particular in the form of a foam sheet, made of pre-expanded, granular foam material, a method for its production and an apparatus for carrying out this method with a mold cavity delimited by a plurality of movable mold walls.

Foam moldings made of pre-expanded granular material, such as pre-expanded, pre-expanded polystyrene, are usually produced in such a way that the pre-expanded material is introduced as a granular raw material - usually by blowing - into a mold cavity, then exposed to steam for caking, then essentially through the Mold walls are cooled through with water and finally ejected mechanically or pneumatically as a finished molded body from the mold cavity which is then opened. In addition, the corresponding foam material that has already been recovered after mechanical comminution has also been used as the raw material for the production of such a molded foam body. However, this has the disadvantage that it is difficult to obtain as a clean material, especially its chemical nature. Accordingly, the moldings produced therefrom are mostly unsightly than those made from fresh raw material, which is why they often meet with rejection even where they could be used without disadvantage, for example as insulation material for construction purposes. The invention is intended to remedy this. It is based on the object of being able to process recovered, shredded foam material to give molded foam bodies, in particular sheets, which are more appealing but also of higher quality than corresponding conventional, produced from recovered foam material.

This object is achieved by the characterizing feature of claim 1. Claims 4 and 7 specify a method which is particularly suitable for the production of the foam molded article in question or a device which is particularly suitable for carrying out this method, while the respective subclaims designate advantageous design options for these objects.

With the claimed invention it is possible to use relatively small amounts of fresh foam raw material, from recovered foam material optically perfect as well as for many purposes for which a corresponding foam molded article produced solely from recovered foam material, for example because of its low binding, It would be qualitatively inadequate to create satisfactory molded foam articles.

Advantageous exemplary embodiments are described in more detail below with reference to the figures. It shows

1 shows a cross section through a corresponding foam molded body in the form of an insulator plate having step folds which correspond to one another on opposite edges,

2 shows a somewhat schematic cross section through a device for producing such a molded foam body using the claimed method in the production of the relevant core from recovered foam material, 3 shows a similar cross section through the same device with an enlarged mold cavity for receiving fresh foam raw material,

4 shows a similar cross section through the device after filling with the fresh foam raw material for the production of the cover layer covering the core of the molded body from this material and

5 shows an enlarged, somewhat schematic longitudinal section through a positioning unit with a pin-shaped holding member and a positioning member of the device according to FIGS. 2 to 4, which is coaxial therewith.

The molded foam body 2 shown in FIG. 1, an insulating plate, has a flat, cuboid core 4 made of recovered foam material and a cover layer 6 of fresh granular foam raw material that completely and completely surrounds the core 4 in this example, which covers the outer contour of the Foam molded body 2 determined. Thus, in the example shown in the cover layer 6, corresponding step folds 8 are formed on opposite edges, which make it possible to connect a plurality of such plates flush, but overlapping one another, as is customary with insulating plates in the construction industry.

The device 10 shown in FIGS. 2 to 4 - but only in its parts relevant to the invention - contains a mold cavity 12 which, at least in any case, is delimited by a plurality of mold walls 14, 16, 18 and 20 which are movable relative to one another. More specifically, the two main mold walls 14 and 16 are movable towards and away from each other, as is the case with foam molds, although it is only usual for opening and closing the mold cavity, while the lateral mold walls 18 and 20 are designed in the manner of a slide and are movable in order to enter the mold cavity 12 retracted or withdrawn from this to be able to. The movement takes place in a manner known per se via guide rods 22 and 24, 26 through working cylinders 28 and 30, 32, as is customary in the relevant technology.

The mold 34 described so far, regardless of the mobility of the mold wall 14, can be divided along the dash-dotted line 24 in a conventional manner in order to open the mold cavity 12 and to remove the finished foam molded body 2 produced therein , ie to be able to eject. In addition, each of the two molded parts 38 and 40 is enclosed by a box 42 and 44, which forms a steam and cooling chamber 46 and 48, respectively. From the steam and cooling chambers 46 and 48, the mold cavity 12 can in turn be acted upon in a conventional manner, for example by means of slot nozzles (not shown) provided in the mold walls 14 and 16, with steam and possibly air. Inside the steam and cooling chambers 46 and 48 there are spray pipes 50, from which cooling water can be sprayed onto the respective mold wall 14 or 16. The foam material is fed to the mold cavity 12 in the usual way through one or more injectors preferably provided in the mold wall 16 (not shown). So far, the device described above is conventional with the exception of the movable mold walls 14, 18 and 20. -

In the meantime, however, the mold cavity 12 continues outside the mold walls 18 and 20 in the form of pockets 52 and 54, which are to be covered by the slide-like mold walls 18 and 20 (as shown in FIG. 2) or are to be exposed (FIG. 3). In addition, the space exposed by the retracted mold walls 18 and 20 can also expand the mold cavity 12 (FIG. 3). The position and width of the pockets 52 and 54 can be determined, as shown, by insert pieces 56 and 58, respectively.

As additional elements, positioning units 60 and 62, each with a plate-shaped positioning member 64 and a coaxial, pin-shaped holding member 66, are also arranged in or on the mold walls 14 and 16, as shown in FIG 5 is shown in more detail and will be described in more detail later.

The device described so far and the function of the parts in question will now be explained on the basis of the method to be carried out with reference to FIGS. 2 to 4:

According to FIG. 2, the mold walls 14-20 assume their position intended for the production of the core 4 of the foam molded body 2 shown in FIG. 1. That the mold cavity 12 is closed by the mold walls 14-20. In this state, the mold cavity 12 is shredded with recovered foam material, e.g. foamed polystyrene, filled, then vaporized from the chambers 46 and 48 through the mold walls 14 and 16 and finally, if necessary, also cooled in order to give the core 4 thus produced sufficient strength so that it is self-supporting.

The mold cavity 12 is then expanded by withdrawing the mold walls 14, 18 and 20 according to FIG. 3, while the core 4 just formed is brought into the central position shown in FIG. 3 by the positioning units 60 and 62 and in it is held. More specifically, while the core 4 is held in suspension by the pin-shaped holding members 66, it is laterally positioned with respect to the mold walls 14 and 16 by the plate-like positioning members 64. The positioning members 64 are then withdrawn into corresponding recesses 68 in the mold walls (FIG. 5).

In the last-described state, the mold cavity 12 according to FIG. 4 is now filled with fresh granular foam raw material, as far as the core 4 leaves room for it. Thereupon, the holding members 66 are also withdrawn. Now the mold cavity 12 is again vaporized from the chambers 46 and 48, as a result of which the granular foam raw material introduced last bakes together and thereby also forms a bond with the core 4. Possibly. at this stage the binding of core 4 itself is also completed.

Now, again, the foam molded body 2, which has been completed so far, is cooled in a customary manner by water again sprayed onto the mold walls 14 and 16, after which the mold cavity 12 is opened and the molded foam body 2 is ejected.

This ejection can take place either by means of air which is blown from the chambers 46 and 48 through the mold walls 14 and 16 into the mold cavity 12, or else by means of the positioning members 64 provided on the mold walls 14 and 16, which thus fulfill a double function can.

As can be seen in FIG. 5, the respective positioning member 64 is located on a hollow shaft 70, in which the associated pin-shaped holding member 66 is guided in a longitudinally movable manner and is even guided in a longitudinally movable manner in a bore 72 in the relevant mold wall, here 16. The recess 68 already mentioned forms a flat, blind hole-like expansion of the bore 72 on the side of the mold cavity 12 in order to receive the positioning member 64 flush with the relevant inner wall surface 74.

The positioning member 64 and the holding member 66 are driven via working cylinders 76 and 78, respectively, which are shown here together and are in any case flanged to the mold wall 16 within the chamber 48. Both cylinders are double-acting. The shaft 70 forms the piston rod of the cylinder 76, while the pin-shaped holding member 66 forms the piston rod of the cylinder 78 and, for this purpose, is guided in a sealed manner through the rear end wall 80 of the cylinder 76.

Both cylinders, 76 and 78, can be controlled separately in an adjustable manner such that the holding member 66 together with the positioning member when the mold cavity 12 is expanded as shown in FIG. 3 - ^~ -

64 extends, but the latter, as already described above, returns before the holding member 66 after it has fulfilled its positioning function. In addition, the stroke of the holding member 66 is dimensioned such that, even when the positioning member 64 is extended, it still protrudes over the latter in order to drill into the core 4. In this way, the core 4 is kept at its original height after the mold walls 18 and 20 have been withdrawn, while its lateral position with respect to the mold walls 14 and 16 is determined by the positioning members 64.

After the mold cavity 12 has been filled with the fresh foam raw material, this takes over the function of the holding members 66, so that they can then also return to their starting position in order not to allow any holes to form in the cover layer 6.

If desired, the mold cavity 12 can be reduced again after filling or even during the subsequent setting process by mutually approaching the mold walls 14 and 16 in order to achieve a denser product and possibly also a better connection of the cover layer 6 to the core 4 to reach. A similar reduction in the size of the mold cavity can also take place during the manufacture of the core after filling with the relevant recovered foam material in order to impart greater density and strength to the core from the outset.

It goes without saying that in addition to foamed polystyrene, such as is available on the market under the trade name "Styrofoam", other foams made of pre-expanded granular foam material are also suitable for the invention, especially foamed polyolefins such as foamed polyethylene and ge ¬ foamed polypropylene. In addition, the core 4, in particular, can consist of a certain mixture of such materials as are often unavoidable in the case of recovered foam. Finally, core 4 and cover layer 6 can also be lent different materials. Insofar as these are unable to form a chemical-physical bond in the production processes under consideration here, such a desired one can also be achieved by a toothing-forming shape of the core 4. Instead of completely encasing the core 4 with the cover layer 6, this can, if desired, also be applied only on one or individual sides of the core, where improved strength and / or a perfect appearance of the molded body 2 is important.

Claims

Claims:

1. molded foam body, in particular -plate, (2) made of pre-expanded granular foam material, characterized in that it has a core (4) of recovered used foam material, which on at least one side has a cover layer (6) made of fresh, possibly also carries different foam aterial.

2. Foam molded body (2) according to claim 1, characterized gekenn¬ characterized in that the core (4) and / or cover layer (6) at least substantially made of foamed polystyrene or foamed polyolefins, such as. Polyethylene or polypropylene.

3. foam molded body (2) according to claim 1 or 2, characterized ge indicates that the core (4) and cover layer (6) are interlocked.

4. A process for the production of a foam molding (2) according to one of the preceding claims, characterized in that first the core (4) is produced in an otherwise customary manner from the recovered, crushed foam material introduced into a mold cavity (12), that thereupon the mold cavity (12) is expanded according to the contour of the cover layer (6) while the core (4) is held in a final position with respect to the expanded mold cavity, that the expanded mold cavity is filled with fresh pre-expanded granular foam raw material and that the latter is then set in the usual way, whereupon the finished molded foam body (2) is removed from the mold.

5. The method according to claim 4, characterized in that the recovered foam material initially, in the manufacture of the core (4), only imperfectly and with the setting of the Cover layer (6) forming foam raw material is only fully set.

6. The method according to claim 4 or 5, characterized in that the mold cavity (12) before or during the setting of the core (4) and / or the cover layer (6) forming foam material is reduced.

7. The device (10) for performing the method according to one of claims 4 to 6, with a by a plurality of movable mold walls (14, 16, 18, 20) limited mold cavity (12), characterized in that in addition to two opposite, ge ¬ oppositely movable mold walls (14, 16) on the periphery of which further slide-like mold walls (18, 20) are provided.

8. The device (10) according to claim 7, characterized in that the slide-like extendable and retractable mold walls (18, 20) have a thickness corresponding to the wall thickness of the cover layer (6) of the foam molded body (2) to be produced.

9. The device (10) according to claim 7 or 8, characterized gekennzeich¬ net that it has retractable pin-shaped holding members (66) for holding the core (4) in the mold cavity (12).

10. The device (10) according to claim 9, characterized in that in addition to the holding members (66) in the mold cavity (12) retractable plate-like positioning members (64) are provided.

11. The device (10) according to claim 10, characterized in that at least some of the positioning members (64) surround holding members (66).

12. The device (10) according to claim 11, characterized in that the relevant holding members (66) and positioning members (64) can be moved by coaxial working cylinders (78, 76) one behind the other.

13. The device (10) according to claim 11 or 12, characterized gekenn¬ characterized in that the movements of the holding members (66) and positioning members (64) are controlled such that the holding members penetrate into the core (4) produced while place the positioning elements on the core so that, before the expanded mold cavity (12) is filled with fresh foam raw material, the positioning elements return to their starting position with respect to the mold wall (14, 16) in question and that after the filling, even before the fresh foam raw material has set, the holding members also return to their starting position.