EP0070285A1

EP0070285A1 - Method and device for the transformation of pvc wastes

Info

Publication number: EP0070285A1
Application number: EP82900300A
Authority: EP
Inventors: Laszlo Nagy
Original assignee: GRANFISH PLASTIC GmbH
Current assignee: GRANFISH PLASTIC GmbH
Priority date: 1981-01-27
Filing date: 1982-01-27
Publication date: 1983-01-26
Also published as: WO1982002512A1

Abstract

Lors de la fabrication et de la transformation de materiaux P.V.C. les dechets qui en resultent sont traites dans un laminoir compose de deux cylindres rotatifs (6, 7) tournant en sens inverse et avec des vitesses de rotation differentes, Les cylindres (6, 7) qui ne peuvent etre chauffes directement seront prechauffes a l'aide de corps de chauffe amovibles (16, 17) avec du courant bon marche durant la nuit Lors du fonctionnement leur temperature sera amenee par frottement et pression jusqu'au point de fusion du materiau P.V.C. Apres qu'une partie du chargement est transformee en une masse ayant une cohesion toute la charge est modelee pour prendre la forme d'un tapis et deposee sous forme d'un rouleau sur les cylindres. Le materiau fondant au contact avec les cylindres forme sur le pourtour du cylindre le plus rapide (7) une feuille qui est enlevee refroidie et enroulee.During the manufacture and transformation of PVC materials, the resulting waste is treated in a rolling mill composed of two rotary cylinders (6, 7) rotating in opposite directions and with different rotational speeds, The cylinders (6, 7) which cannot be heated directly will be preheated using removable heaters (16, 17) with cheap current overnight During operation their temperature will be brought by friction and pressure to the melting point of the PVC material After a part of the load is transformed into a mass having a cohesion all the load is shaped to take the form of a carpet and deposited in the form of a roll on the cylinders. The material melting on contact with the cylinders forms around the periphery of the fastest cylinder (7) a sheet which is removed cooled and rolled up.

Description

Process and device for processing PVC waste

The present invention relates to a method for processing PVC waste, which is obtained in irregular form during PVC film production, into films. the PVC waste being passed through the nip between two rollers rotating in opposite directions and at different speeds.

The invention further relates to a device used to carry out this method with two rotating and counter-rotating rollers of unequal speed, the mutual distance of which forms a nip can be adjusted.

In the industrial production and processing of foils from polyvinyl chloride (PVC), waste of irregular shape is produced in the context of the known kerf manufacturing and processing methods. These wastes are initially processed according to the method known today with regard to their further processing; granulated and then either fed to an extruder and formed into shaped parts or brought into sheet form in a directly heated rolling mill. Not only several separate machines and corresponding operating personnel are required to carry out these known methods, but also the

Further processing of the waste is also possible with a chen expenditure of energy. The processing of such PVC residues is therefore generally considered to be so unprofitable that only the PVC film manufacturers themselves have appropriate waste recycling facilities.

It is therefore the object of the present invention to propose a method and a device for processing the wastes which constantly arise during PVC film production and processing, in such a way that the processing can be carried out without interrupting operation on a single, relatively inexpensive device with considerable energy savings . The method according to the invention and the device used to carry it out are defined in independent patent claims 1 and 6.

While it was previously common for film manufacturers to process their own PVC waste for profitability reasons, the new process increases the economic efficiency of processing so significantly that the operation of their own PVC waste recycling plant is also worthwhile by other companies. The quality of the film obtained can be described as very good, especially since PVC waste containing dyes or foreign materials such as paper etc. can also be processed without any problems.

An exemplary embodiment of the method according to the invention is explained below with reference to the accompanying drawing. 1 is a simplified perspective view of a device for processing PVC waste,

2 to 9 are simplified vertical sections of the device and serve to illustrate different phases of the processing method and

FIG. 10 is a schematic perspective illustration of a cooling system downstream of the device according to FIG. 1.

The device shown in perspective in FIG. 1 in its important components has a housing designated in its entirety with 1, which has a bottom 2 and two side walls 3 and 4. Furthermore, a cover 5 is provided which can be placed on the housing from above and closes the same in a heat-insulating manner. All mentioned wall parts of the housing 1 are preferably designed so that the housing has the lowest possible heat losses during operation.

In the side walls 5 and k, a rolling mill is arranged, which has two rotatably mounted rollers 6 and 7. The rollers are connected in a known manner to a drive, not shown, and run in opposite directions, as indicated by the arrows. The speed of the two rollers 6 and 7 is different, ie the roller 6 rotates at a relatively low speed n, while the higher speed N of the roller 7 in a preferred embodiment between 1.1C and 1.27 times that Speed n lies. In a box 8 placed in front of the housing 1, a known mechanism is accommodated, which allows the roller gap (gap width) between the two rollers 6 and 7 to be regulated by means of a hand crank 9. A corresponding crank 10 acts on a similar mechanism provided on the side wall 4 of the housing. Of course, it would also be possible to actuate the two adjustment mechanisms by means of a single hand crank or also by means of a drive device.

On the upper edges of the side walls 3 and 4, two boundary plates 11 and 12 are loosely suspended, so that these plates, the lower edges of which are approximately 2 mm away from the rollers 6 and 7, can be loosely pivoted about their upper suspension axes against stop bolts 28. Depending on requirements, the two boundary plates 11 and 12 can also be lifted off the rollers and removed. The limit plates are held at the aforementioned distance from the rollers by the stop bolts 28.

Between the side walls 3 and 4, three auxiliary rollers 13, 14 and 15 are also hung loosely rotatable. The arrangement of these Kilfswalzen, the function of which will result from the description of the method, is to be chosen so that the auxiliary orphans can be easily assembled by hand and also removed again. The means for easily releasable storage of such rollers are known to the person skilled in the art and therefore do not need to be described in the present context. 2, the device is further provided with two radiators 16 and 17, the shape of which is adapted to the pair of rollers 6/7 and can be placed over the rollers from above and below. In this operating position, the rollers are thus enclosed by the radiators 16 and 17. The upper radiator is designated 16 'in its mounting position. The radiators are preferably made of a material with high heat storage capacity and have an electric heating element. After the end of work, the radiators are placed on the rollers and switched on in good time by a timer, for example 1 to 2 hours before the start of operation. The radiators are also put on during breaks for heat insulation and additional heating. In this way, the temperature of the two rollers 6 and 7 consisting of solid steel can be brought to the desired initial temperature of approximately 80 ° C. at low cost.

After the two rollers have been brought to the aforementioned initial temperature, the PVC waste to be processed, ie the entire batch, is introduced and the rollers are set in rotation. The roller spacing (gap width) denoted by d in FIG. 3 is set to an optimal value, for example 0.5 to 1.5 mm. The material is now conveyed downward through the roll gap, as shown in FIG. 3, the rolls heating up further due to friction and pressure. After this first pass of the material, approximately two thirds of the same are separated, while one third, as indicated by the dash-dotted line R ₁ , is again applied to the whales from above. This process continues until for example, repeated two to three times until the mentioned third of the waste batch emerges from the roll gap in a continuous manner, ie in the form of a partially tattered mat or web B (FIG. 4). The web B can now be placed around the faster rotating roller 7, whereupon the two thirds of the waste batch separated in an earlier phase are again fed onto the rollers from above (line R ₂ in FIG. 4). After the coating rotating on the roller 7 has been severed at some point S (FIG. 4) over the entire width of the roller, the web 3 collects at the bottom of the device and can now be moved from here into the space between the two boundary plates 11 and 12 fill in (Fig. 5).

Before attaching the boundary plates, the required dye or plasticizer can be added and processed with the web.

In all of the previously described and also the subsequent phases of the method according to the invention, it is of crucial importance that the roll nip always remains filled with a minimum amount of material. Above all, this is necessary so that orphans 6 and 7, whose mutual distance is extremely small, do not move together.

After the web 3 has been placed on the rollers according to FIG. 5, the cover 5 is put on so that the web material does not lose too much heat in the subsequent processing. The web emerging from the nip is now around the faster rotating orphan 7 laid (arrow in Fig. 4) and first runs around with it until the coating adhering to the roller circumference has the desired thickness, which is less than the thickness of the end product to be produced (PVC film). As soon as the covering has reached this thickness, it is separated at one point and removed from the roller in the form of a roll or a stack 18. In view of the very small gap width, the throughput time of the entire waste batch can be, for example, between 30 and 60 minutes. The roller temperature rises constantly due to the roller pressure and friction.

After the material bale 18 has reached a certain size, it is placed against the circumference of the roller 7, as shown in FIG. 6, and a first auxiliary roller 13 (cf. also FIG. 1) is hung into the device. The bale 18 thus rotates in contact with the roller 7 and the auxiliary roller 13 and grows gradually until the second auxiliary roller 14 and finally the third auxiliary roller 15 have to be used. Before the material located above the nip is completely used up, the bale 18 is placed on the two rollers 6 and 7, as shown in FIG. 7. The constantly rotating rollers 6 and 7 have now reached a temperature. which corresponds to the melting temperature of the PVC material. As a result, the bale melts at the contact points designated 19 and 20 and the melting material flows down the circumference of the rotating orphans through the nip. (Fig. 8). The width of the whale gap is now matched to the thickness of the desired PVC film, and so a film-like loading is formed on the circumference of the roller 7 lay F, which can be separated after a certain time and removed in the direction of the arrow (FIG. 9).

10, the film running off the roller 7 is passed through a cooling device which has a plurality of conveyor belts 21, 22 and 23 arranged one above the other and a plurality of fans 24, 25, 26. After the film F has passed through this cooling system, it is wound up on a roll 27.

The numerical data mentioned in connection with the above description are only examples and can be varied by the person skilled in the art within the scope of the inventive concept. For example, the amount branched off during the first pass of the material (FIG. 3) does not of course have to be exactly one third of the total batch, but can, for example - vary between a quarter and the total of the batch depending on the type of material.

In addition to the energy savings and the low purchase price of the entire system, the described method has the advantage that PVC contaminated with foreign bodies can also be processed. Dyes, paper and various textile residues are embedded in the PVC material as they pass through the rolling mill and mixed intensively with this material, so that a homogeneous mass is created.

In the embodiment according to FIG. 6, it would also be possible to place the auxiliary rollers at points 15, 14 'and 13' to attach. It is important here that the rotating material roll remains in constant contact with the hot roller 7.

The preheating of the rollers 6/7 can also be done directly, i.e. by heating elements built into the rollers, e.g. Steam pipe.

Claims

P a t e n t a n s r u c h e

1) Process for processing PVC waste, which are obtained in the PVC production and processing, into films, the PVC waste being passed through the nip between two rollers rotating in opposite directions and at different speeds, characterized in that the rollers before applying a batch of PVC waste to a temperature below the melting temperature of the PVC, the entire batch of PVC material is passed through the nip at least once, at least a fraction of the material passed through is repeatedly passed through the nip until the material emerges in the form of a coherent web, whereupon the web is laid around one of the two rollers, preferably the faster rotating one, and, after one or more further roller passes, cut and rolled up on the circumference of the roller and the rotating roller on the circumference of the roller for keeping warm and others Materialau Support is supported, whereupon the material roll thus formed, as soon as it has reached the desired final size, is placed on the two rolls over the roll gap and when the melting point is reached, the gap width is increased to the thickness of the desired film and the material from the circumference of the roll flows down through the nip and from the circumference of the faster rotating roller can be taken and cooled.

2) Method according to claim 1, characterized in that after the passage of the entire PVC material about 2/3 is separated and only about 1/3 is repeatedly passed through the nip, whereupon the remaining material, comprising about 2/3, is returned to the rolling mill is fed.

3) Method according to claim 2, characterized in that the rollers are accommodated in a thermally insulated housing which, after the addition of the remaining material, is closed to the previously separated fraction by an upper cover.

4) Method according to one of claims 1 to 3, characterized in that the two rollers are first preheated to about 80 ° C and the desired operating temperature is carried out by regulating the amount of material supplied to the rollers.

5) Method according to one of claims 1 to 4, characterized in that said material roll is supported by a loosely rotatable support roller arranged parallel to the faster rotating roller and further support rollers are mounted with the growth of the material roll, the distance from which by the Vertical and horizontal planes (E ₁ / E ₂ ) increases.

6) Facility to carry out the procedure according to claim 1, with two rotating and counter-rotating rollers of unequal speed, the mutual, a roller gap forming distance is adjustable, characterized in that both rollers are arranged in a thermally insulated housing and the material feed area located above the roller gap is limited by removable flaps which, in their operating position, come close to the roller surfaces, with a removable device which is independent of the rollers being provided for preheating the rollers.