DE4315014C2 - Method and device for producing molded parts from plastic waste - Google Patents

Description

The invention first relates to a method for the manufacture provision of molded parts from shredded, with Plastic waste provided plastic material that in a filled in from the lower part and cover mold and Isobarically heated and sintered in at least one press is, the mold then in another press is transported.

Such a method is for example from the DE-OS 31 49 701 known, in which a method and Device for producing filter plates with a sealing edge and flat central area made of thermoplastic material is shown and described. This procedure and the Device are used in particular with filter plates of different strengths. For this purpose a compressible made of silicone rubber Edge strips and a prefabricated core frame and  Support cores made of solid plastic material in a lower part the form inserted, the areas between the Core frame and the support cores filled with plastic granulate become. After closing the mold, the latter is in one Heating press under constant pressure so far heated that the plastic granules melt and core frame and at least melt the support cores. This is supposed to an intimate connection between the aforementioned materials surrender.

Unfortunately, you can with the previously device described in no way on economic Wise molded parts from shredded, from different Produce plastic waste existing material.

The object of the invention is therefore one possible simple and economical process for the production of Molded parts made of plastic waste Creating plastic material.

The object of the invention is compared to the above. was standing the technology in particular through the following features of Claim 1 solved, after which the sintered, from the Plastic material existing plastic filling sealing immersion of the lid in the lower part isochoric is cooled in a controlled manner.

The method according to the invention initially has the essential advantage that it is economical is possible from large amounts of crushed, from different plastic waste material To manufacture intermediate or end products that have a high  Have dimensional accuracy, so that post-processing of manufactured products is not necessary. In that after the isobaric heating or sintering of the Plastic filling when changing the mold from the heating press the filling into the cooling press under the influence of the The resulting gas expands during the Cooling in the cooling press the possibility of the resulting To calibrate the product.

In addition, in the method according to the invention advantageous way in particular the filling process Plastic waste in the heating press as well as the heating press such simply be designed. By calibrating the Products to be manufactured only in the second process step during cooling, on the one hand, is an even one Distribution of the crushed plastic waste in the Heating press and on the other hand also a uniform introduction the pressure forces are not required. This doesn't simplify only the procedure, but sets the Investment costs one for the inventive method suitable heating press significantly.

In contrast to the closest prior art, at which the filling of the mold from a solid core frame and support cores as well as a small gap having plastic granulate filling, which at the heating only compressed by a small amount is, is a loose according to the inventive method Fill from different plastic wastes below Effect of pressure with simultaneous sintering in volume significantly reduced. While the plastic filling after the Invention is only sintered, d. H. the surfaces of the  Plastic components are melted on the stand technology at least completely the plastic granulate melted. There is also one in this state of the art special, all-round sealing of the mold cavity by the Compressible edge strips made of silicone rubber necessary.

In a further embodiment of the invention The process is that in a press mold Plastic filling first in different presses gradually heated and then cooled. This means on advantageous way that each individual press one in has substantially constant temperature, which is beneficial to the lifespan of the process needed devices affects.

The manufactured by the inventive method Molded parts also have the advantage that they are intermediate or manufactured using minimal energy End products that have a high strength and different from those despite their composition plastics do not pose a risk to the environment. So on the one hand, the existing ones in the plastic waste Germs killed by the heat treatment and others on the one hand, the finished molded part is not leachable.

Modifications of the method according to the invention result itself from further claims.

Furthermore, the invention relates to a device for Manufacture of molded parts from crushed, with Plastic material provided with plastic waste, with  at least one heatable and one coolable press and one consisting of a lower part and a lid Die, which by means of a transport device from a Press to the next is movable.

From the above-mentioned DE-OS 31 49 701 is already one Device for producing filter plates or the like. known, but with a prefabricated core frame massive plastic and only the rest of the Plastic starting material is filled in as granules. With With the help of this device it is not possible to economically large amounts of plastic waste to process customized products.

In addition, from DE-OS 36 37 905 (s. 4 and 5) a device for production known from objects made of thermoplastic, in which the lower part of a mold has a recess, in which dips a cover part. However, this device is not of the generic type, since this is the plastic granulate outside of the mold in a swiveling basket Hot air, steam or a similarly hot medium so far is heated that the surfaces of the plastic granules melt. After this heating process, the granules are in poured the mold and the movable molding inside of the depression pressed down.

This device has the disadvantage that it is relative is complex. In addition, it should be with this known device may be difficult to make accurate products produce, because a uniform filling of the  melted granules over the entire surface of the Deepening is difficult to achieve.

The object of the invention is therefore to provide a device for Manufacture of molded parts with plastic waste provided plastic material, which if possible is simple and allows it to be economical reasonable effort to produce molded parts.

The solution to this problem essentially arises from the fact that in the device the lower part of the mold at least one recess for receiving the Has plastic material, which during the Pressing process in the recess dipping lid is essentially completely sealed, as well as a Immersion of the lid limiting device is provided is, with the lower part of the mold parallel to Conveying direction arranged side flanges has, whereby the mold with the press open automatically coupled in motion with a transport device is.

With this simple solution according to the invention, it is now possible from large amounts of plastic waste each dimensionally accurate, high strength products to create, the starting material in the device according to the invention to about 20% of the original Volume is reduced. Due to the special constructive Features, especially those under sealing the recess immersed and self-centered lid as well as that Immersion of the lid-limiting device can on the one hand, the shape should be very simple and  on the other hand, there is no need to manufactured semi-finished and finished products due to possible existing inaccuracies afterwards to edit.

The inventive design of the molds made possible light it also that by simply opening the Press the mold almost onto the transport device falls and is automatically transported to the next press where it can be resumed directly. Here the transport system can advantageously be used as a conveyor chain, Conveyor belt, push bar system, guide roller system or the like be trained.

An advantageous further development of the fiction This device has several presses arranged in series on, which form an overall system, the presses starting from the first one arranged gradually increasing temperature thereafter gradually falling temperature.

This larger capacity device has the basic advantage that all are connected in series th presses with each other through the same transport device are connected, so that the effort for the transportation of a individual molds from press to press is very low. Dar moreover, the individual presses essentially have one constant temperature, so that the material stress reduced and the life of each press Lich increased.  

Ultimately, the invention also relates to a work process ren for the use of a device according to the claims 8 or 9, which consists of several presses arranged in series is formed by means of a transport device are interconnected, in any operating state each press has no mold and the presses, each with the press-free press between them include, open or close at the same time, the die, each in the die-free Press upstream press is arranged by means of Transport device in the mold-free in the conveying direction Press is moved.  

It is through this working method according to the invention possible in an advantageous manner with a device for Manufacture of molded parts with a relatively low order driving power for the presses, because with Verwen only two at a time Presses are opened or closed.

In summary, the costs for one of the like device due to the significantly reduced instal drive power reduced.

The invention is based on the following description of the embodiments in more detail explained.

Show it:

Fig. 1 is a perspective view of a compression mold,

Fig. 2 is a simplified sectional view of a closed press,

Fig. 3 is an illustration of Fig. 2 was in the open to,

FIGS. 4 and 5 is a schematic representation of an Ar beitsverfahrens for use of an existing from being arrange in series th press devices entire plant and

Fig. 6 is a schematic representation of an overall device constructed from parallel parallel devices.

In the drawings, a pressing device for the manufacture of molded parts from plastic waste is designated as a whole by the reference number 10 .

Fig. 1 shows the existing cast iron or aluminum die 11 which consists of a base 12 and a lid 13. The lower part 12 has a right-angled recess 14 for receiving the material to be pressed, the recess 14 having a size which enables the cover 13 to be immersed in the latter in a sealing manner while the lower part 12 is closed .

On both sides of the mold 11 , a transport device 15 is indicated by dash-dotted lines, with which the mold 11 can be transported in the direction of the arrow marked x. The transport device 15 can, for. B. as a conveyor chain, conveyor belt, push belt system, guide roller system or the like. The facing to the Transporteinrich device 15 side walls 16 are provided on both sides with a flange 17 , by means of which the mold 11 is mounted overall on the transport device 15 .

In FIGS. 2 and 3, a press apparatus 10 is shown including schematically IMP EXP. One can see an upper, movable press plate 18 and a lower, movable press senplatte 19 between which a mold 11 is arranged. On both sides of the pressing device 10 , the transport device 15 is also shown schematically.

Ultimately, heating and cooling pipes 20 are present in the upper and in the lower press plate 18 and 19 , with which the press plates 18 and 19 can be brought to a certain desired temperature. For this purpose, the heating or cooling tubes 20 can be charged with a heat exchanger medium.

In the closed state of the press device 10 shown in FIG. 2, the press mold 11 is pressed against the upper press plate 18 by means of the lower press plate 19 , the cover 13 tending to be immersed in the recess 14, not shown, of the lower part 12 . The lid 13 closes the recess 14 so that no plastic waste can escape to the outside. It is also seen that the die 11 direction when closing the Preßvor 10 is lifted by the transport device 15, so that the side 17 above the processing Transporteinrich arranged 15th

In Fig. 3, however, the open state can be seen a press. In this case, the lower press plate 19 moves downward, the mold 11 following this movement until the side flanges 17 rest on the transport device 15 . In this case, the transport device 15 moving in the x direction (see FIG. 1) can transport the mold 11 to the next pressing device 10 .

The operating sequence of a press device 10 shown in FIGS . 1 to 3 is now as follows:

First, a defined amount of coarsely comminuted plastic waste is filled into the depression 14 of a mold 11 and then the lid 13 is placed on it. Thereafter, the mold 11 is transported by means of the transport device 15 into a first pressing device 10 heated via the heating pipes 20 , which is then immediately closed. Under the action of a pressing force F (see FIG. 2), the cover 13 is pressed into the depression 14 of the lower part 12 . In the isochoric control of the pressing device 10 , for example, stops are present on the side walls of the depression 14 , which limit the immersion of the cover 13 .

In the manufacture of the molded parts there is a volume reduction of the filled plastic waste by about a factor of 5. As a result of the heating of the plastic waste in the mold 11 by means of the upper and lower press plates 18 and 19 , the contact heat acting on the mold 11 becomes Plastic waste is heated, the plastic chips being sintered together with softening.

Thereafter, the pressing device 10 opens until the pressing mold 11 with the side flanges 17 rests on the transport device 15 and can be transported to the next pressing device 10 . In this pressing device 10 , however, it is a cooled, in which the mold 11 and the blank is cooled after closing in the course of a further half an hour to the release state.

Basically, it is provided that the removed To use heat to heat other moldings  the energy expenditure for the production of a molding mini lubricated.

With a desired molded part thickness of approximately 25 mm, the heating time of the molded part is approximately half an hour, the plastic waste being heated to approximately 180 ° Celsius. Basically, the residence time of the plastic waste in a device 10 depends on the thickness of the molding to be produced. It should be taken into account that a quadrupling of the dwell time is necessary when the molding thickness is doubled.

FIGS. 4 and 5 then show a plurality of devices 10 Preßvor composite overall system R for the manufacture of molded parts from waste plastics, which switches ge in series and are connected to one another via the transport means 15. The peculiarity of this overall system R be is that each pressing device 10 has a gradually higher or lower temperature.

In the present example, the overall system R consists of pressing devices a to i, with, for example, the pressing devices a to e having a gradually higher temperature and the pressing device f to i a gradually lower temperature. In effect, this means that the plastic waste gradually passes through all the pressing devices a to i during the heating and cooling times. It should be noted that the filling station and the demolding station are not shown in FIGS. 4 and 5.

FIGS. 4 and 5 also show a completely be-determined working method of using such a Ge overall plant R. basis of this operating method is that the number of steps the overall system R passing through press molding 11 is always at one less than the number of press devices a to i of a complete system R.

In Fig. 4 is indicated schematically that the Preßvor directions e and g were opened or closed simultaneously in the direction of the arrows marked with y and z respectively. While there is a press mold 11 in each of the press devices e and g, the press device f has no press mold 11 . For this reason, the mold 11 of the pressing device e, which device e is uniformly connected to the transport device 15 when the pressing device e is opened, can be transported in the x-direction into the “empty” pressing device f. When the pressing device f is reached, the pressing mold 11 is then automatically picked up by the same and loaded with a pressing force F, while at the same time the pressing device d upstream of the pressing device 11 having no pressing mold 11 opens against the transport direction x.

In the next cycle, the mold 11 located in the pressing device d is transported by means of the transport device 15 into the "gap" which results in the pressing device e. Ultimately, the working process is continued in that the pressing device e closes and the pressing device c is opened at the same time.

In this way, the simultaneous opening or closing of two pressing devices and the transport of a mold 11 in the next, a "gap" having pressing device a to i, the drive power required for the overall system R is significantly reduced. This is achieved in that the drive power only has to be dimensioned such that two pressing devices a to i can be opened or closed at any time and the pressing force F provided in all other pressing devices a to i is maintained.

Due to this working process, the position moves the "press-free" press device constantly around.

Ultimately, Fig. 6 shows a further alternative to the construction of an overall system P from pressing devices 10 '. Here at the entire system P consists of a parallel connection of two series-connected Preßvorrichtun conditions 10 ', of which the first is heated and the second is cooled. This overall system P is enclosed by a common transport device 21 , the respectively arranged in series cooled or heated pressing devices 10 'are connected to each other with a further transport device 22 , which has a transport connection to the common transport devices 21 by means of a transfer station, not shown.

The entire system P thus consists of an essentially rotating transport device 21 , in the area of which a filling and demolding station 23 for the molds 11, including the lid placement station 24, can be seen. The filled with plastic waste molds 11 are then by means of the rotating transport device 21 , which, for. B. transfer car can be transported to the transfer station to the series-connected pressing devices 10 'leading further transport device 22 . There takes the form of a chain conveyor Transportein direction 22, the die 11 and transports it to the pressing devices 10 '. After the dwell time in the first, heated pressing device 10 ', the die 11 falls in the manner previously described on the chain tenbahn 22 and is transported to the cooled press device 10 . After the mold 11 has reached the Entformungszu stand, it is moved to the transfer point with the rotating common transport device 21 and from there to a cover removal station 25 and the Ent forming station 23 transported.

After removal from the mold, the molds 11 can in turn be filled with plastic waste in the filling station 23 .

Claims (14)

1. Process for the production of molded parts shredded, provided with plastic waste Plastic material, which is made from a base and lid existing mold and filled in at least one Press isobarically heated and sintered, the The mold is then transported to another press is in which the sintered, from the plastic material existing plastic filling when sealing the immersion Isochor controlled lid is cooled in the lower part. 2. The method according to claim 1, characterized in that that the plastic filling located in a mold first gradually heated in different presses and then cooled. 3. The method according to claim 1 or 2, characterized characterized that to hide the Plastic waste filling into the mold a Plastic film or a layer of granules is introduced. 4. The method according to any one of the preceding claims, characterized in that in the mold Reinforcement materials or fillers are introduced. 5. The method according to any one of the preceding claims, characterized in that the isochoric cooling energy generated to heat the plastic material is being used.   6. Apparatus for producing molded parts from comminuted plastic material provided with plastic waste, with at least one heatable and one coolable press ( 10 , 10 ', ai) and a mold ( 11 ) consisting of a lower part ( 12 ) and a cover ( 13 ) , Which can be moved by means of a transport device ( 15 , 22 ) from one press ( 10 , 10 ', ai) to the next, and in which the lower part ( 12 ) of the press mold ( 11 ) has at least one recess ( 14 ) for receiving the plastic material which is completely sealed by the dipping during the pressing into the recess (14) cover (13) substantially, and a dipping of the cover (13) defining means is provided, wherein the lower part of the mold on which is arranged parallel to the conveying direction limits side flanges has, whereby the mold is automatically coupled to a transport device when the press is open. 7. The device according to claim 6, characterized in that the transport device ( 15 , 22 ) is designed as a conveyor chain, conveyor belt, push bar system, guide roller system or the like. 8. Device according to one of claims 6 or 7, there characterized in that several Pres sen (a-i) form an overall system (R), the presses (a-i) starting from the first arranged one stu then gradually increasing temperature falling temperature.   9. The device according to claim 8, characterized in that that the device consists of a number (n) of presses (a-i) and a number (n-1) of dies. 10. Device according to one of claims 6 or 7, characterized in that each individual device consists of two, each shape ( 11 ) successively receiving presses ( 10 , 10 '), one of which can be heated and cooled. 11. The device according to claim 10, characterized in that a plurality of such devices are arranged parallel to each other in an overall system (P) having a common filling or demolding station ( 23 , 24 , 25 ), which with each device ( 10 ') Is connected via a common transport device ( 21 ). 12. The apparatus according to claim 11, characterized in that the presses ( 10 ) arranged one behind the other are connected to one another by means of chain tracks ( 22 ) and to the filling or demolding station ( 23 , 24 , 25 ) via transfer carriages. 13. The device according to one of claims 6 to 12, characterized in that the device is provided with a heat recovery system, which in the cool th presses ( 10 , 10 ', ai) energy for heating the upstream presses ( 10th , 10 ′, ai) uses. 14. Working method for the use of a device according to claims 8 or 9, which is formed from a plurality of presses arranged in series, which are connected to one another by means of a transport device, wherein in each operating state a press has no mold and the presses ( e and g; d and f), each of which enclose the press-free press (f; e) between them, are simultaneously opened or closed, the press mold ( 11 ), respectively, being upstream of the press-free press (f; e) Press (e; d) is arranged, is moved by means of the transport device ( 15 ) into the press (f; e) which is free of compression mold in the conveying direction (x).