WO1998041374A1

WO1998041374A1 - Disposal system for plastic

Info

Publication number: WO1998041374A1
Application number: PCT/JP1997/000915
Authority: WO
Inventors: Nobuaki Arakane; Masakatsu Hayashi; Yoshiyuki Takamura; Tsutomu Hasegawa
Original assignee: Hitachi, Ltd.
Priority date: 1997-03-19
Filing date: 1997-03-19
Publication date: 1998-09-24

Abstract

A disposal system for selecting and recovering reusable resources from used composite plastic comprising a crushing process, a washing and grain size adjusting process and a plastic selecting process. The composite plastic disposal system having combined the washing and grain size adjusting process in which mechanical impacts and frictional force are imparted to crushed plastic for washing it and adjusting the grain size thereof and the plastic selecting process in which a liquid cyclon is used can remarkably improve the accuracy in selecting plastic to be selected and recovered to thereby selectively obtain plastic of high purity, whereby it is possible to use recovered plastic as reusable resource material.

Description

Specification

Plastic processing systems

Technical field

The present invention relates to a composite plastic processing system for separating and recovering useful resources from a plastic composite product occupying most of general waste and a plastic bottle of container and packaging waste.

Background art

Plastic products include those that use composite plastics in which different types of plastics are combined in multiple layers and those that are formed by combining several types of plastics. Among them, the production of light, durable and sanitary plastic bottles is increasing rapidly. Therefore, the amount of plastic bottles, which are waste containers and packaging, in the large amount of general waste is increasing year by year. For PET (polyethylene terephthalate) bottles that belong to plastic bottles that were conventionally treated as general waste, urgent promotion of the use of recycled resources is urgently needed, and a system has been established that can promptly collect and recycle bottles. Is required.

As a conventional processing system for collecting recycled materials from plastic bottles, there is a recycling plant for PET bottles described in Environmental Technology (1996.vol.25 P19 ~ P22) 現状 Current Status and Issues of Bottle Recycling ''. .

The processing system at the recycling plant first cleans the collected plastic bottles and removes foreign substances such as aluminum caps. The plastic bottle is then crushed into flakes to facilitate material selection from the composite material used in the plastic bottle.L The crushed pieces from this plastic bottle are then washed with a flake washing machine using an Alririch cleaning solution. The crushed fragments are sorted into two types: those that float in the specific gravity liquid and those that settle. After that, through a drying process, to separate the plastic into higher-purity plastic, the crushed pieces from which the low-density labels were removed by using wind power were used to prevent the mixing of various colored desinka and other labels. Collect as recycled material. Only the crushed pieces selected here are washed and dried again, and Collect as stick.

In the above conventional technology, a large amount of washing water is sprayed plastically to wash dirt and odors attached to plastics, so large amounts of wastewater are generated from the treatment system. Also, capital investment is required for wastewater treatment considering secondary pollution caused by wastewater.

Further, the specific gravity separation process using a specific gravity liquid in the above-described conventional technique has a problem that the selection rate (recovery rate) is poor.

Also, there are known methods for treating used plastic bottles described in JP-A-1148517 and methods for recovering polyester resin recycled materials from bottles described in JP-A-68207. ing.

In the former, the used plastic bottles that have been heat-shrinked are separated by material, and then crushed by material to improve the sorting operation and crushing efficiency. The latter involves adding an inorganic powder material to the crushed PET bottle crushed pieces and using mechanical friction to select and collect the crushed pieces by material.

Both processing methods heat PET bottles to facilitate the separation of materials from the bottles, but the above separation method separates the materials by hand, and it takes human labor to process a large amount of plastic bottles. There is a problem of too much. The latter requires a step of washing the selected plastic and a step of collecting the inorganic powder material to remove the inorganic powder material adhering to the selected crushed pieces, which increases equipment costs.

An object of the present invention is to provide a plastic processing system that sorts and collects high-quality plastics by material so that used plastic bottles can be used as recycle materials.

Another object of the invention is to recover high quality plastics.

Disclosure of the invention

The purpose is to crush a composite plastic whose main material is made of plastic, and to apply mechanical impact force and frictional force to the crushed pieces crushed by this crushing device. This is achieved by providing a dry-type washing device, which can be used, and a sorting device that separates each plastic of the same system by utilizing the difference in specific gravity of the washed crushed pieces.

Further, the other objects are a crushing step of crushing a composite material plastic whose main material is formed of plastic, a washing step of washing crushed pieces crushed by the crushing device, and a specific gravity of the washed crushed pieces. A sorting step for separating each plastic of the same system by using the difference, wherein when switching to a composite plastic in which both or one or both of the color or the material of the composite plastic material to be treated is different, the washing or cleaning in each step This is achieved by providing a step of performing the following.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the flow of the plastic bottle processing system.

FIG. 2 is a schematic diagram of the processing system.

Figure 3 shows the flow of the plastic bottle processing system.

Figure 4 shows the flow of the plastic bottle processing system.

Fig. 5 is a schematic diagram of the metal sorting process in the plastic bottle treatment system.

FIG. 6 is a system flow of a pretreatment process.

Fig. 7 shows the operation flow when processing is performed by switching the plastic bottle of the product to be processed.

FIG. 8 is a diagram for explaining the details of the washing and sizing device.

FIG. 9 is a diagram illustrating details of the hydrocyclone.

BEST MODE FOR CARRYING OUT THE INVENTION

First Embodiment A first embodiment of the present invention will be described with reference to the processing system flow of the plastic bottle of FIG. 1 and the outline of the processing system of FIG.

Composite plastics include PP (polypropylene), PVC (polyvinyl chloride), and PUR (polyurethane) composites, PET (polyethylene terephthalate) and PP-composite plastic bottles, like automotive interior materials. However, in this embodiment, the composite plastic A plastic bottle will be described as an example.

The main types of plastic bottles used for beverages, foods, detergent liquids, etc. are PET (polyethylene terephthalate), PP (polypropylene), PE (polyethylene), PS (polystyrene), and PVC (polychlorinated). In this embodiment, a PET bottle will be described as an example of a resource recovery process from a used plastic bottle. In general, PET bottles are made of PET only and PET are used for the container, and PP is used for the neck.Plastic film labels are used on containers to identify self and other products. Wound force, or paper label glued.

The processing system 1 shown in Fig. 1, which collects the plastic used in the plastic bottles by material, consists of a crushing process 2, a washing and sizing process 3, a wind sorting process 4, and a plastic sorting process 5. .

In FIG. 2, the PET bottle 6 is first put into the crusher 7, crushed to a particle size suitable for the sorting process in the subsequent process, and the crushed pieces of the PET bottle 6 are washed. Supply to plastic polishing machine 8. The plastic polisher 8 includes a screw 11 that rotates by the drive of the input unit 9 and the motor 10, a screen 12 that removes finely pulverized materials, and a discharge that periodically discharges crushed pieces larger than the screen. It is composed of a valve 13 and outlets 14 and 15 for discharging fragments.

The impact of the rotation of the screw blade 11 is applied to the crushed pieces of the PET bottle charged from the charging section 9, and the crushed pieces remaining at the outermost periphery of the screw wing 11 are combined with the screw wing 11 and the screen. A frictional force is applied by compression of the crushed pieces that have stayed between 12 and inside the polishing machine 8. By applying impact and frictional force to the crushed pieces of the PET bottle in this way, the washing effect of removing labels and dirt attached to the surface of the crushed pieces can be obtained without using washing water, and the crushing process The treatment alone has the effect of sizing the crushed pieces having a coarse crushed section into a smooth shape.

Here, the principle of the dry washing and sizing method by the washing and sizing machine 8 will be described with reference to FIG. 8 by taking as an example a crushed piece of a PET bottle made of PET and PP crushed by the crusher 7. The washing / rectifier 8 has a screw blade 11 driven and rotated by a motor 10 at the center of a cylindrical container, and an inlet 9 for charging plastic is provided at the upper part of the container. On the lower wall surface of the container, a screen 12 is provided to allow a particle having a particle size of about 1 mm or less to pass therethrough, and the material passing through the screen 12 is discharged to a discharge port 14. In addition, a discharge valve 13 that automatically opens and closes periodically is provided on the downstream side of the flow of the crushed pieces at the bottom of the container. When the discharge valve 13 is opened, the plastic inside the container and the particle size becomes 1 Discharge 15 mm or more from the outlet. Air from the air cyclone flows from the inlet 9 to the outlet 14 inside the container.

When crushed pieces of plastic are introduced from the inlet 9, the crushed pieces falling into the container are conveyed to the downstream side by the rotation of the screw blades 11. If crushed pieces continue to be supplied, the density of crushed pieces that remain on the downstream side will increase, and pressure will be applied to the crushed pieces. Friction force is applied to the crushed pieces by friction. When an impact force and a frictional force are applied to these crushed pieces, the surface is polished, and a cleaning effect of removing dirt such as an adhesive adhered to the crushed pieces can be obtained. At the same time, the projections of the crushed pieces are polished to smooth the shape. That is, a sizing effect can be obtained.

The dirt and finely pulverized plastics removed from the crushed pieces by the washing and rectifying action pass through the screen 12 and are discharged from the discharge port 14 by the suction force of the air cyclone 16. When sufficient washing and sizing effects are obtained for the crushed pieces, the discharge valve 13 is opened, and the crushed pieces are discharged from the discharge port 15 by the suction force of the blower 19.

As described above, the cleaning / rectifier 8 not only does not use the cleaning liquid as in the related art, but also has higher continuity than a batch process in which the cleaning / rectifier 8 is placed in a cleaning tank and cleaned.

In Fig. 2, the fine powder that has passed through the screen 12 with a particle size of about 1 mm or less is injected into the air-cyclone 16 from the discharge unit 14 by the suction force of the air-cyclone 16 in the wind separation process 4 . The air cyclone 16 uses the swirling flow of air generated by driving the blower 16a to discharge gas with low specific gravity from above and solid with high specific gravity from below. You. As a result, crushed pieces of PET bottles are collected in the fine powder inlet 16b.

The crushed pieces from which the finely pulverized material has been removed (dry-cleaning) contain plastic or paper labels made of various colored designs in addition to the plastic of the container and neck. Since it is necessary to collect plastic of the same color and the same material for collection, the label must be removed from the crushed pieces. To remove the labels, the wind separation device 17 and air-cyclone 18 provided in the wind separation process 4 are used.

Fragments with a particle size of 1 or more are discharged from the discharge unit 15 by the suction force of the blower 19 by periodically opening and closing the discharge valve 13 installed in the discharge unit 15, and the wind separator 17 Supplied to In the wind separator 17, an updraft is generated by the drive of the fan 18 a provided in the air-cyclone 18, and the low specific gravity L, plastic film, paper, etc. 8 and collected at the collection port 20. On the other hand, PET and PP plastics, which are fragments of high specific gravity that cannot be transported by the ascending airflow, are discharged from below and sent to the plastic sorting process5.

In the plastic sorting process 5, the material is sorted by using the difference in specific gravity between the specific gravity liquid and the plastic, and the PET (specific gravity 1.27) and PP (specific gravity 0.97) of the target plastic have a specific gravity of 1 Because water is around 0, water is used as the specific gravity liquid. Depending on the object to be sorted, a specific gravity liquid different from water may be used.

The plastic sorting process includes a stirring tank 21, a liquid cyclone 23 for sorting plastic, and fcK devices 26 and 30 for dewatering the sorted plastic.

The stirring tank 21 is composed of a water tank for storing water as a specific gravity liquid and a stirrer 21a, and stirs the plastic put into the water to remove bubbles adhering to the surface of the plastic while placing the plastic on the bottom of the water tank. Water and plastic are supplied to the hydrocyclone 23 by settling and facilitating transport of the plastic by the circulation pump 22.

As will be described in detail later, the hydrocyclone 23 generates a swirling water flow due to the flow of water along the cylindrical wall surface, and at this time, forms a central air column of air sucked from a lower discharge portion, The water is discharged from the lower discharge part 23a and the upper discharge part 23b. When the mixed plastic of PET and PP is supplied to the hydrocyclone, the crushed pieces of high specific gravity PET are swirled on the wall of the hydrocyclone by the swirling water flow and discharged from the lower discharge section 23a, while the PP of low specific gravity is The crushed pieces are discharged from the upper discharge section 23b while rotating around the air column, and the ability to sort PET and PP is reduced.

The sorted PET crushed pieces are conveyed to the dehydrator 26 by the water amount adjuster 24 at a water amount suitable for transfer to the dehydrator 26, and excess water passes through the water amount adjusting plate 24a and is stored in the water tank. 2 5 The water in the water storage tank 25 is returned to the stirring tank 21 by the circulation pump 27 to circulate the water in the plastic sorting process. The dehydrator 26 cuts off the water adhering to the PET crushed pieces by the high speed rotation of the rotating blades 26a, and collects it in the collection port 28. Similarly, the selected PP is supplied with excess water to a water storage tank 25 by a water amount adjuster 29, and is recovered at a recovery port 31 by the treatment of a dehydrator 30.

Here, the principle of separation of the hydrocyclone 23 will be described with reference to FIG. 9 using a crushed plastic fragment of PET and PP. The hydrocyclone 23 was provided in a tangential direction with a cylindrical container having a conical discharge portion 23 a at the bottom, a cylindrical insertion tube 100 provided at the center of the container, and a container wall surface. It has an input port 101.

The water (specific gravity liquid) supplied from the inlet 101 generates a downward swirling flow 102 along the container wall, and an upward swirling flow 103 at the center. When the mixed plastic crushed pieces are supplied together with water into the container from the inlet 101, the PP plastic crushed pieces having a specific gravity of less than 1.0 are sucked into the upward swirling flow 103 (pushed out together with the water flow), The inside of the insertion tube 100 rises and is discharged from the upper discharge part 23 b of the hydrocyclone. PET plastic fragments with a specific gravity greater than 1.0 are strongly swirled by the centrifugal force and swirled downward. It is discharged from the lower discharge part 23a without any change. Based on such a principle, the mixed plastic crushed pieces are separated into those having a specific gravity larger than the specific gravity of water and those having a smaller specific gravity. In addition, when metals are selectively separated from a mixture of metals such as aluminum and plastic, upper and lower By controlling the suction force of the upward swirling flow by changing the parameters such as the diameter of the discharge section, the amount of water, the length of the insertion pipe, etc., plastic having a higher specific gravity than water is discharged from the upper discharge section, and only metals The metal is separated from the plastic by discharging the water from the lower discharge part by putting it on the downward swirling flow.

In order to verify the effect of combining the washing and sizing process in this example and the plastic sorting process using a hydrocyclone, the sorting performance was compared with the conventional technology. The plastics used were PET and PP, and two types of plastic were used: coarsely crushed pieces that had been coarsely crushed by a crusher and sized crushed pieces. In addition, the performance of the sorting device was compared using a specific gravity sorting device that sorts plastics only by floating up and down with respect to the specific gravity liquid. Table 1 shows the sorting performance of the combination of the crushed pieces and the sorting device. Sorting performance is compared with a recovery that indicates the quality of the plastic.

table 1

After passing through the dry washing and sizing steps as shown in this example, the crushed pieces are sorted by a conventionally known specific gravity (composite crushed pieces are put into slowly flowing water, and the crushed pieces are crushed more heavily than water. When the particles are settled and the lightly crushed pieces are put into a sorter, the recovery rate is only 872%, whereas the coarse crushed pieces are dry-cleaned and sized. The result showed that the recovery rate increased by 4.2% even with the same sorter. When the sorting method was a hydrocyclone, it was 96.1% for coarsely crushed pieces, but 99.3% for sized crushed pieces, which was a practically acceptable result. The reason will be described below. When a thin plastic injection molded like a plastic bottle is crushed, it is cut with a crusher.The crushed section of the plastic becomes coarse, and the crushed pieces of PET containers are peeled off by laminating sheet force. The shape looks like it hangs. If the plastic crushed pieces of such a shape are treated by a floating-sink type specific gravity selection method utilizing the specific gravity difference of the material using a specific gravity liquid, the crushed cross section and the ability to remove air bubbles attached to the gap between the laminated plates, It becomes difficult and the apparent specific gravity of the plastic changes due to the adhesion of air bubbles, and the sorting performance is reduced. For this reason, the purity of the recovered plastic is low and it is difficult to maintain the quality suitable for recycled materials.

On the other hand, in the case of the dry washing and sizing process, the particle size is adjusted, so that the adhesion rate of air bubbles is reduced, and the sorting / collection (recovery) power is greatly improved even with the conventional floating / sedimentation type specific gravity separator.

On the other hand, the liquid cyclone achieves a high recovery rate of 96.1% even with coarse crushed pieces, but unlike centrifugal separators of the sedimentation type based on the difference in specific gravity, the centrifugal force of the water flow is used as described above. For sorting. With this water flow, the crushed pieces that have undergone the dry washing and sizing process are almost free of bubbles, and a recovery rate of about 100% is obtained.

Next, a second embodiment will be described with reference to FIG. Fig. 3 shows the flow of the processing system that collects the plastic used in plastic bottles by material. The target plastic bottles 32 are bottle containers without aluminum caps and rings, plastic or paper labels, and are made up of PET for the container and PP for the neck. It is a plastic bottle. This may be performed in the pre-processing step in the reprocessing plant, or may be separated by the consumer in advance.

The plastic bottle 32 supplied to the processing system 33 composed of the crushing process 2, washing and sizing process 3, and plastic sorting process 3 is crushed in the crushing process 2 into crushed pieces having a particle size suitable for sorting. The crushed pieces are put into a dry washing and sizing step 3, where the dirt adhering to the plastic is removed, and the crushed pieces are sized in a smooth shape. Then, the washed and peeled crushed pieces are supplied to a plastic sorting step 5 where they are separated into PET and PP. As a result, in addition to the effects of the first embodiment described above, plus the crushed aluminum This has the effect of eliminating the need for a step of selecting tics.

Next, a third embodiment will be described with reference to FIGS. Fig. 4 shows the flow of the system, and Fig. 5 shows the outline of the metal separation process. In addition, the plastic bottle 37, which is the target of the sorting process, has an aluminum cap or ring, attached with a plastic or paper label, a PET container for the container, and a PP for the neck. It is composed of

A plastic bottle 37 is processed by a processing system 39 composed of a crushing process 2, a washing and sizing process 3, a wind sorting process 4, a metal sorting process 38, and a plastic sorting process 5. The composite crushed pieces used in the crushing step 2 are dry-washed in the washing and sizing step. The composite crushed pieces treated in the washing and sizing step 3 are fed to the wind separator 17 in the wind sorting step 4 to be converted into plastic and paper labels with low specific gravity and plastic and metal with high specific gravity. The labels are collected and collected by the air-cyclone 18 into the collection port 2 (). On the other hand, the crushed pieces of plastic and metal from which the labels have been removed are put into a stirring tank 40 comprising a water tank and a stirrer 41 in the metal sorting step 38, and are stirred by the stirrer 41 in the water tank. In addition, while removing bubbles adhering to the crushed pieces, the settling of the crushed pieces to the inner bottom of the stirring tank 40 is promoted, and the circulating pump 42 discharges the crushed pieces from the stirring tank 40 to remove the liquid cyclone 4. Conveyed to 3. A swirling water stream of water, which is a specific gravity liquid, is generated inside the hydrocyclone 43, and this water stream is a stream that swirls the wall of the hydrocyclone 43 and discharges water from the lower discharge portion 44, and a central portion. It is divided into a flow of sucking up the inside of the insertion tube 45 installed in the water and discharging water from the upper discharge part 46. The difference between the hydrocyclone 43 in the metal sorting process 38 and the hydrocyclone 23 in the plastic sorting process 5 is characterized by the balance of the amount of water discharged from above and below. The liquid cyclone 43, which is divided into aluminum (specific gravity 2.7) and plastic (specific gravity 0.97 to 36), which has a higher specific gravity, has a large upward discharge so that only all plastic is discharged from above. Is given.

The separation of aluminum and plastic by hydrocyclone 4 The water is discharged from the lower discharge part 44, passes through the water amount regulator 47, and removes the water adhered to the aluminum by the dehydrator 48, and collects it in the recovery port 49. The plastics are conveyed from the upper discharge section 46 to the plastic sorting process, and through the plastic sorting process 5 described above, the plastics are separated by PET and PP materials. Through these steps, plastic can be sorted and collected by plastic from plastic bottles containing aluminum. Next, a fourth embodiment will be described with reference to FIG. Fig. 6 shows the flow of pretreatment in a treatment system for sorting and collecting plastic bottles by material.

Plastic bottles 55 are not limited to PET bottles, but are of various types made of PVC and PP. In addition, colorless and colored bottles are available. The processing system 50 is a system having any of the processing functions described in Embodiments 1 to 4, and is used in combination with the preprocessing step 51 that enables advanced recovery processing from a plastic bottle. . This pre-treatment step 51 is composed of the work steps of removing the aluminum cap 52, selecting the material of the bottle 53, and selecting the color of the bottle 5. In the present embodiment, a processing method in which a PET bottle as a transparent container is selectively taken out from the plastic bottle 55 and the plastic is selected and collected by the processing system 50 will be described as an example.

When the plastic bottle 55 is carried into the pretreatment step 51, the aluminum cap and aluminum ring attached to the bottle container are manually removed in the aluminum removal step 52, and metals are mixed into the collected plastic pieces. To prevent This aluminum removal step 52 can also be configured by automatically cutting the neck of a pet bottle. Next, the plastic bottle container from which aluminum was removed is supplied to the container material selection process 53, and the spectroscopic method using near-infrared light is used.The container material is selected by a plastic material identification device, and the container material is selected. By collecting them separately, plastics such as PVC (specific gravity: 1.25 to 1.36) and PET (specific gravity: 1.27) that are difficult to sort in the plastic sorting process 5 near the specific gravity are preliminarily separated. The identification mark displayed on the plastic bottle can be read out by image processing for selection. Next, the PET containers whose materials have been selected are supplied to the container color selection process 54, and the color of the containers is determined by a plastic color identification device using an RGB comparison method of transmitted light. Sort and collect containers by color. Remove the cap from the plastic bottle 5 5 5 2, sort the material of the container 5 3, sort the color of the container 5 4, and supply the PET bottle of the transparent container taken out in the order of 4 to the processing system 50 to obtain high quality PET. Collect PP plastic.

Incidentally, if the processing order of the aluminum removing step 52 and the material selecting step 53 is changed, the aluminum removing step 52 is required for each material. For this reason, it is better not to change this order. Material sorting 53 and color sorting 54 can be interchanged.

Next, a seventh embodiment will be described with reference to FIG. Fig. 7 shows a system flow in which the processing system 50 switches to plastic bottles with different materials and containers of different colors in the pre-treatment process, and separates and collects the plastic in the processing system 50. In this embodiment, an operation method of the present system will be described by taking as an example a case where a PET bottle of a transparent container is processed in a process after processing a PET bottle of a colored container.

When the processing system 50 is operated by switching from colored PET bottles to transparent PET bottles, the colored PET crushed pieces that were processed in the previous process adhered and remained inside each machine such as crushers and sorters. The cleaning and cleaning of the treatment system 50 is performed to prevent the mixing of different-colored plastics into the collected plastics.

In the dry crushing process 2, the washing and sizing process 3, and the air separation process 4, the colored plastic is blown off using an airbrush and the colored plastic is removed by cleaning each device. In addition, in the wet metal sorting process 38 and the plastic sorting process 5, the water in the water tank is replaced, and the colored plastic adhered is removed by cleaning each device. By supplying a transparent PET bottle 57 to the processing system 50 from which colored plastic has been removed by washing and cleaning, transparent PET and PP are sorted and collected.

As described above, according to these embodiments, it is possible to increase the sorting rate in the sorting of plastics, and to reduce the reprocessing of water used in the process.

Claims

The scope of the claims

1. A crushing device that crushes composite plastics whose main material is made of plastic, a dry-type cleaning device that applies mechanical impact and friction to the crushed pieces crushed by the crushing device, A plastic processing system comprising a sorting device that uses the difference in the specific gravity of the crushed pieces to separate the same type of plastic.

2. The plastic processing system according to claim 1, wherein the sorting device is a hydrocyclone.

3. A crushing device that crushes composite plastics whose main material is made of plastic, a dry-type cleaning device that applies mechanical impact and friction to crushed pieces crushed by the crushing device, A plastic processing system comprising: a device for removing metal fragments from the crushed pieces; and a sorting device for separating the same type of plastic by utilizing a difference in specific gravity of the crushed pieces from which these metals have been removed.

4. The plastic processing system according to claim 3, wherein the apparatus for removing the metal pieces is a liquid cycle mouth, and the sorting apparatus is a liquid cycle mouth.

5. A crusher that crushes composite plastics whose main material is made of plastic, a dry-type cleaning device that applies mechanical impact force and frictional force to crushed pieces crushed by the crusher, A wind separator that removes crushed fragments from the washed crushed fragments by wind power and a crusher that separates each plastic of the same system by using the difference in specific gravity of crushed fragments obtained by the wind separation With plastic processing system.

6. The plastic processing system according to claim 5, wherein the sorting device is a hydrocyclone.

7. A crushing device for crushing composite plastics whose main material is made of plastic, a dry cleaning device for applying mechanical impact and frictional force to the crushed pieces by the crushing device, A wind power sorting device that removes crushed fragments having a low specific gravity from the washed crushed fragments by wind power, a device that removes metal fragments from crushed fragments obtained by the wind power sorting, and a device that removes these metals. Using the difference in the specific gravity of the crushed pieces A plastic processing system with a separating device.

8. A crushing step of crushing composite plastics whose main material is made of plastic, a washing step of washing crushed pieces crushed by the crusher, and a crushing step using the specific gravity difference of the washed crushed pieces. And a step of performing washing or cleaning in each of the steps when switching to a composite plastic in which both or one or both of the color and the material of the composite plastic material to be processed are different. Plastic processing method.