CA2069812A1

CA2069812A1 - Method of processing plastic coated textiles and system for implementing this method

Info

Publication number: CA2069812A1
Application number: CA 2069812
Authority: CA
Inventors: Jurgen Rummer
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-05-31
Filing date: 1992-05-28
Publication date: 1992-12-01
Also published as: DE4121024A1; ATE123823T1; EP0515946B1; DE59202499D1; EP0515946A1

Abstract

ABSTRACT OF THE DISCLOSURE

A method is proposed for processing plastic coated textiles, particularly plastic backed textile floor covering and for recovering the textile fibers and plastics contained therein. The method includes the following process steps:
- chopping the materials to be processed into small chips approximately 5 x 5 to 10 x 10 mm2 in size;
- mixing the chips with water, thus forming a pumpable substance;
- comminuting the chips in a mill, thus forming a pulp;
- dewatering and drying the pulp;
- mechanically separating the fibers from the resulting plastic granules.
Also disclosed is a system for implementing the method which is characterized by the following component groups:
- a chip making device composed of longitudinal and transverse cutters for the materials to be processed;
- at least one intermediate storage means for the chips with connected dosing and transporting device;

- at least one stirrer for producing the chip suspension:
- at least one mill for converting the chip suspension into a pulp;

- at least one screening device with connected dryer;
- at least one mechanical separating device for separating the fibers from the resulting plastic granulate, with the component groups of stirrer, mill and screening device being connected with one another by means of lockable liquid conduits.

Description

~0~98~2 CROSS FcEFERENCE TO RELATED APPLI CATION

This application claims the priority of Applications Ser.
No. P 41 17 931.5, filed May 31, 1g91, and P 41 21 024.7, filed June 26~ 1991, in the Federal Republic of Germany, the subject matter of which is incorporated herein by reference.

BACKGROUND OF_THE INVENTION

The present invention relates to a method of processing plastic coated textiles, particularly plastic backed textile floor covarings and ~or recovering the textile fibers and plastics contained therein. The invention further relates to a system for implementing this method.
Textile floor coverings that are backed with plastic are employed, for example, as carpeting in living quarters, offices and other buildings. They also find widespread use in motor vehicles, particularly in passenger cars, but also in busses and other public transporting means. Due to the increasingly stricter rules for protection of the environment, the manufacturers of, or dealers in, such floor coverings are fre~uently obligated to take back the old coverings if a corresponding article is newly purchased. Moreover, considerable quantities of unusPd coverings are cut off along --: ~ -- 2 --:
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, . . - , , the edges, due to cuttiny around obstacles and the like during the production of such floor coverings. In every case it is necessary to reprocess the existing remnant pieces and thereby recover, as much as possible, the valuable textile fibers and also the plastic material employed to back the coverings.

However, textile ~loor coverings of the described type are not the only textile-plastic composite substances for which a reprocessing task exlsts. Plastic covered tarps and covers also are included in this task. In the past, it has been the custom in such cases to simply burn the remnants which, however, on the one hand, was a considerable stress on the environment and, on the other hand, involved the destruction of valuable raw materials.

SUMMARY OF THE INVENTION

To solve this problem, a method is proposed which is composed of the following method steps:
- chopping the materials to be processed into small chips, thus forming a pumpable substance;
- mixing the chips with water and comminuting them in a mill, thus ~orming a pulp;
~ dewatering and drying the pulp;

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- mechanically separating the fiber; from the resulting plastic granules.
In corresponding tests it has been observed that with such a treatment it is possible to practically completely separate the plastic particles from the fibers and cause the plastic to aggregate into small granulate particles. After the treatment, the textile fibers are available free from the plastic in an aqueous suspension so that it is possible to separate the two components ~after the pulp, that is, the comminuted material, has been dewatered and dried. Such a separation can bP accomplished in di~ferent ways, for example by mechanically beating the mixture (simi]ar to thrashing) but also by shaking it on screens or by blowing air over it.
In order to bring the material to be processed into a form suitable for processing in comminutors, that is mills, and forming a pulp, it is necessary to first break them into small chips, in which case the chips should have a size that is suitable to be stirred with water into a pumpable mixture.
In practical tests, a chip size of 5 x 5 to 10 x 10 mm2 has ~0 been found satisfactory. This size is here recommended with preference although the implementation of the method is not strictly bound to this size.
In the next process step, the chips are then further comminuted in a miIl and form a pulp. Devlces known from the :: :

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paper making industry, such as disc refiners or cone mills, have been found to be acceptable mills. These mills operate at a sufficient speed to be economical; on the other hand, they also do not transfer any more energy to the material being ground than is absolutely necessary for working; in particular, the textile fibers are treated very gently during their treatment in these mills, with the degree of working being adjustable by varying the grinding gap.
The pulp resulting from the grinding is then dewatered and finally dried completely. The then existing mixture of textile fibers and plastic granulate can be separated into fibers and granulate particles - as mentioned - by beating and blowing. The fibers as well as the granulate particles are reusable. The fibers may be processed, for example, into coarse yarns which can a~ain be used for the manufacture of floor coverings, but also for scrub rags and the like. The granulate particles may be melted in a known manner in extruders and can again be used as coatings. As is customary in the plastics industry, the recycled granulate should not be processed alone, rather these recycled materials should be added in quantities of 20 to 40% to fresh granules so as to obtain as the final product plastics that have the desired quality characteristics.

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8 ~. 2 However, it i5 easier to reprocess the granulate particles in heated mixers or heated stirrers.
If the fibers are composed o~ spinnable plastics, particularly polyamide, they may be spun again once they have been freed of the backing components. The advantage i5 here that new, unmixed polyamide (or some other spinnable plastic) is available again for reuse from which high quality yarns can again be produced.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention also relates to a system for implementing the method. This system will now be described in greater detail with reference to the attached drawing figure. q'he sole figure is a schematic representation of the system. The description below is dependent upon the flow of the materials to be processed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The carpet sections to be processed are initially transferred by way of a magnetic separator 1 to a feeder conveyor ~. The maqnetia sep r~t r removes all magnetizable : -.:

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metal components from the material to be pro~essed and thus protects the subsequent comminuting devices against damage.
From conveyor belt 2, the pieces travel into a chopping device 3 that is equipped with longitudinal and transverse cutters 4. In this device, the initially planar carpet pieces are broken into small chips of a size suitable for further processing. Their size is advantageously 5 x 5 to 10 x lo mm2. The chips produced in this way now travel over conveying means (not shown in detail) into intermediake containers 5, 5' and 5''. The drawing shows three such intermediate containers; the precise number depends of course on the size of the system and is not critical.
From the intermediate containers, the chips can be removed as desired and then travel to a subsequently arranged dosing and transporting system 6. With the aid of this device a predetermined quantity is conducted into a stirrer 7. The stirrer is additionally supplied with water through conduits 8, 9 and 10. Water conduit 8 is here in communication with a water reservoir 11 and may be supplied by way of a dosing pump 12.
In stirrer 7 a water-chips mixture is produced in this way which is composed according to an accurate recipe. This mlxture is conducted through a correspondingly dimensioned ccndu~t 13 and check valves 14 and 15 tc a mill 16, for - ' - ' - : :
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example a disc or cone refiner. This mill i~ driven with theaid of an electric motor 17 and comminutes the incoming chips to such a degree that they form a pulp together with the water that serves as the conveying means. The pulp may here be circulated as required through valves 18 and 19 as long as desired or it may be taken out of circulation through a valve 20 and a connected conduit 21. If necessary, water from container 11 may be added through a valve 22. Depending on the consistency of the materials to be comminuted, grinding may be necessary for a longer period of time in which case the chips-water mixture and the pulp resulting therefrom must be circulated. In such cases it may be useful to include an intermediate container (not shown in the drawing) in the circulation system.
The finished pulp as it finally leaves through conduit 21 travels through a collection staga 23 to a screening device 24. The drawing shows here a longitudinal screening device equipped with suction boxes 25. Instead of this longikudinal screening device, a circular-screen dewatering machine may also be employed.
The water extracted through suction boxes 25 travels through a separator 26 to conduit 10 which selectively conducts the clean water to stirrer 7 or to water container 11. If the latter is the case, a filter 27 may be connected ': ~ , :
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2B~98~2 in between. The air present in the separator is conducted outside through a conduit 28 and an exhaust ~an 29.
The dewatered comminuted material travels from screeniny device 24 to dryer 30 which is shown in the drawing as a belt dryer e~uipped with a suction hood 31.. Instead of a belt dryer, a drum dryer may also be employed to advantage.
Finally, the dry material~ which is now composed of a mixture of textile fibers and pla5tic granules, reach~s a separator 32 in which the fibers are separated from the granules and are separately discharged through conduits 33 and 34.
The wet portion of the system may be rinsed out using water container 11. In that way it can be ensured that ~ibers of different compositions or fibers to be processed 1~ successively are not mixed with on~ another.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

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Claims

1. A method for processing plastic coated textile materials, particularly plastic backed textile floor coverings and for recovering the textile fibers and plastics contained therein, characterized by the following method steps:
- chopping the materials to be processed into small chips;
- mixing the chips with water, thus forming a pumpable substance;
- comminuting the chips in a mill, thus forming a pulp;
- dewatering and drying the pulp;
- mechanically separating the fibers from the resulting plastic granules.

2. A method according to claim 1, characterized in that the substances to be processed are cut down to a chip size of 5 x 5 to 10 x 10 mm2.

3. A method according to claim 1, characterized in that the chips are comminuted in a disc or cone mill.

4. A method according to claim 1, characterized in that the dried comminuted material is separated into fibers and plastic granulate by beating and blowing.

5. A system for implementing the method of claim 1, characterized by the following component groups:
- a chip making device composed of longitudinal and transverse cutters for the materials to be processed;
- at least one intermediate storage means for the chips with connected dosing and transporting device;
- at least one stirrer for producing the chip suspension:
- at least one mill for converting the chip suspension into a pulp;
- at least one screening device with connected dryer;
- at least one mechanical separating device for separating the fibers from the resulting plastic granulate, with the component groups of stirrer, mill and screening device being connected with one another by means of lockable liquid conduits.

6. A system according to claim 5, characterized in that the mill is a cone or disc refiner.

7. A system according to claim 5, characterized in that the screening device is a longitudinal screening device equipped with associated suction boxes.

8. A system according to claim 5, characterized in that the screening device is a circular-screen dewatering machine.

9. A system according to claim 5, characterized in that the dryer is a belt dryer which is heated with hot air.

10. A system according to claim 5, characterized in that the suction boxes of the screening device are connected with the stirrer and/or the water container and the air extraction side of the separator is brought into the open by way of an exhaust fan.

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