JP5093061B2 - Plastic sorting method and plastic sorting apparatus - Google Patents

Description

  The present invention relates to a plastic sorting method and a plastic sorting apparatus for sorting and collecting, for example, crushed plastic pieces used for recycling according to materials.

In order to reduce CO ₂ emissions related to global warming and to effectively use limited resources, methods for recycling plastics such as used home appliances have been actively developed in recent years. Plastics can be recycled by re-pelling used plastics to make new molded materials, thermal recycling to recover heat by burning, and thermal decomposition to oil and monomers for plastic raw materials. There is chemical recycling to reuse. Among them, material recycling is the most suitable method. However, in the reuse of plastics, the characteristics of recycled plastics deteriorate when mixed with plastics of different materials, so technology that identifies recovered plastics with high accuracy is important. It is. As a method for discriminating the material of plastic, infrared spectroscopy using infrared rays is an excellent method with high accuracy. However, in this spectroscopic method, when the recovered plastic to be discriminated is black, all of the irradiated infrared rays are absorbed, and a necessary spectrum cannot be obtained, making discrimination difficult.

Therefore, in the plastic identification device according to Patent Document 1, the surface is scraped with a blade to thin the plastic, the scraped plastic is collected and collected, the infrared spectrum is measured, and the spectrum obtained by infrared spectroscopy is used. There has been proposed a method for identifying plastics by comparing and comparing infrared spectra of various plastics obtained in advance. As a result, even if the recovered plastic is black, it is possible to accurately and reliably sort using the ATR (Attenuated Total Reflection) method.
JP 2002-168777 A

  However, in the conventional plastic identification device, the thinning method by scraping off the used product to be disassembled can be used for discriminating large parts at the level of manual disassembly, but different materials after disassembly are mixed. There was a problem that it was difficult to use for sorting plastic pieces.

  The present invention has been made to solve the above-described problems, and a plastic sorting method and plastic sorting capable of sorting and collecting a mixture of a plurality of types of crushed plastic pieces made of different materials according to materials. The object is to provide a device.

In order to solve the above-mentioned problem, the plastic sorting method according to claim 1 of the present invention is a process of thinning by heat softening and pressing a crushed plastic piece containing plastic with a small amount of infrared transmission. And the step of irradiating the thinned plastic flakes with infrared rays, the step of detecting the infrared transmission spectrum from the plastic flakes, and comparing the infrared transmission spectrum with the infrared transmission spectrum of a known plastic, The method includes a step of performing identification, and a step of sorting and collecting the identified plastic flakes for each material.

  Further, in the plastic sorting method according to claim 3 of the present invention, the step of melting the surface of the crushed plastic piece with a heated transfer roller, and transferring the surface layer of the melted plastic piece to the transfer roller; The process of irradiating the transferred plastic film with infrared light, the process of detecting the infrared transmission spectrum from the plastic film, and comparing the infrared transmission spectrum with the infrared transmission spectrum of a known plastic to identify the material of the plastic film And a step of sorting and collecting plastic pieces for each material from the identified plastic film material.

According to a fourth aspect of the present invention, there is provided a plastic separating apparatus comprising: a thinning device for thinning a piece of plastic by heat softening and pressing a crushed plastic piece containing plastic with a small amount of infrared transmission ; Infrared light source that irradiates the plastic flakes with infrared rays, an infrared detector that detects the infrared transmission spectrum from the plastic flakes, and compares the infrared transmission spectrum with the infrared transmission spectrum of known plastics to identify the plastic flake material And a collection device that sorts and collects the plastic flakes identified by the identification device according to the material.

  According to a sixth aspect of the present invention, there is provided a plastic sorting apparatus, wherein the surface of the crushed plastic piece is melted by a heated transfer roller, and the surface layer of the melted plastic piece is transferred to the transfer roller. Infrared light source that irradiates the transferred plastic film with infrared light, infrared detector that detects infrared transmission spectrum from the plastic film, and comparison of the infrared transmission spectrum with the known infrared transmission spectrum of plastic film And a collection device for sorting and collecting plastic pieces according to the material from the identified plastic film material.

According to the present invention, it is difficult to sort by infrared spectroscopy by heat softening and pressing a crushed plastic piece containing a plastic with a small amount of infrared transmission mixed with a plurality of different materials made of different materials. Even if it is the black plastic which is, there exists a remarkable effect that the plastic piece crushed with high precision can be sorted efficiently according to material.

Hereinafter, a plastic sorting method and a plastic sorting apparatus according to an embodiment of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a schematic perspective view showing a plastic sorting apparatus according to Embodiment 1 of the present invention. FIG. 2 is an enlarged view of the thinning unit.
As shown in FIG. 1, a plastic sorting device 1 supplies a first plastic piece 2a, a second plastic piece 2b, and these plastic pieces 2a and 2b made of different crushed materials to be sorted. A feeder 3; a shooter 4 for dispersing and conveying the plastic pieces 2a and 2b supplied by the feeder 3; a thinning device 7 comprising an extruding roller 5 and a rolling roller 6 for applying a constant pressure to the plastic pieces 2a and 2b; The shooter 9 that conveys the first plastic slice 8a and the second plastic slice 8b that have been sliced by the slicer 7, the infrared lamp 10 that irradiates the conveyed plastic slices 8a and 8b with infrared rays 10a, Infrared detector 11 for detecting the infrared transmission spectrum of plastic flakes 8a and 8b, and a known plastic The identification device 12 for comparing and comparing with the infrared transmission spectrum and identifying the material, the air gun 13 that operates according to the signal from the identification device 12, and the plastic flakes 8a and 8b that have been selected by the air gun 13 and blown in a predetermined direction are collected. And a recovery device 15 including recovery containers 14a and 14b.

Next, the operation principle of the plastic sorting apparatus will be described with reference to FIGS.
Crushed plastic pieces of different materials are produced in a variety of recycling processes that collect valuable metals and glass from used home appliances, office machines such as copy machines, or automobiles. It is a crushed mixture of resin molded products (outer diameter of several mm to several tens of mm). In order to reuse plastics, it is necessary to select and collect the plastic with as high purity as possible (for example, with a purity of about 99%) from the viewpoint of maintaining the quality of the recycled plastic.

  The to-be-sorted plastic in which the first plastic piece 2a and the second plastic piece 2b of different materials having a thickness of 2 to 3 mm crushed for recycling are mixed is supplied from the feeder 3 to the upper shooter 4. , Distributed and transported. Next, the plastic pieces 2a and 2b that have slipped down are crushed by pressing in a state of being heated and softened by the extruding roller 5 and the rolling roller 6 of the thinning device 7, and have a thickness less than 0.1 mm. Thinned. The temperature of the rolling roller 6 is set to be equal to or higher than the softening temperature of the plastic to be selected, for example, 100 ° C. Further, the thin plastic pieces 8 a and 8 b are transported by the lower shooter 9, and the infrared rays 10 a irradiated by the infrared lamp 10 are transmitted through the plastic thin pieces 8 a and 8 b and reflected by the surface of the shooter 9 while sliding down. The infrared transmission light 10b transmitted through the plastic thin pieces 8a and 8b again is detected by the infrared detection device 11, and the infrared transmission spectrum is obtained. The obtained infrared transmission spectrum is compared and compared with the known infrared transmission spectrum of plastic by the identification device 12, the material of the plastic flake irradiated with infrared rays is identified, and the time and position of sliding down on the shooter 9 are synchronized. When this plastic flake is the first plastic flake 8a, it is blown off by the air jetted from the air gun 13, and blown off by the air gun 13 and put into the collection container 14a. The plastic flake is also the second plastic flake 8b. In this case, the air gun 13 is not sprayed and is directly put into the collection container 14b, and the plastic pieces 2a and 2b are sorted and collected respectively.

  Since the rolling roller 6 heats and softens the resin, a metal such as aluminum or stainless steel is desirable, and the shooter 9 also serves as an infrared reflector, so a metal such as aluminum or stainless steel whose surface is mirror finished is suitable. is there. In consideration of the infrared transmission amount of plastic with a small amount of infrared transmission, the thickness of the plastic flakes must be 0.1 mm or less, and the gap between the extrusion roller 5 and the rolling roller 6 is 0.1 mm in accordance with this. It is set narrowly. Here, as the wavelength of infrared rays, those in the range of 1.0 μm to 2.5 μm can be used.

  In the plastic sorting apparatus of the present invention, since the material is identified by the infrared transmission spectrum, a plastic mixture (for example, ABS (acrylonitrile butadiene styrene) resin and PS (PS) is difficult to sort by the specific gravity sorting method because the specific gravity is close. It can also be applied to the selection of polystyrene) resin mixtures).

  In particular, black plastic usually has a small amount of transmitted infrared light and a large variation in the amount of transmitted light simply by crushing, and it is often difficult to identify the material, but in the present invention, the thickness of the plastic piece is reduced, By making the thickness uniform, the amount of transmitted infrared light is increased and variations are reduced to improve the identification accuracy.

  As described above, according to the first embodiment of the present invention, the plastic piece to be selected is thinned by the rolling roller, so that the material can be accurately obtained even if the amount of transmitted infrared rays is small like black plastic. Thus, it is possible to identify them, and there is a remarkable effect that the accuracy of sorting plastics can be improved.

  In the first embodiment, the case of measuring infrared transmission spectrum by irradiating a plastic piece that slides down on an inclined shooter and measuring infrared transmission spectrum is described. It may be the case of irradiating, irradiating the thinned plastic conveyed on the mesh belt with infrared light from the upper or lower part of the belt, and setting the infrared light transmitted through the thinned plastic to the lower or upper part of the belt It may be a method of obtaining an infrared transmission spectrum by receiving light with an infrared detecting device, and has an effect of facilitating identification with respect to a plastic made of a material having a small amount of transmitted light.

  In addition, as a thinning device for thinning a plastic piece, instead of an extrusion roller and a rolling roller, a flat heating plate and a pressure plate for pressing are used to heat and soften the plastic by batch processing. You may make it thin and produces the same effect.

Embodiment 2. FIG.
FIG. 3 is a schematic perspective view showing a plastic sorting apparatus according to Embodiment 2 of the present invention. FIG. 4 is an enlarged view of the thinning unit.
As shown in FIG. 3, in the plastic sorting apparatus according to the second embodiment, the sorting apparatus 1 includes a first plastic piece 2a, a second plastic piece 2b made of different materials to be sorted, and these plastics. The feeder 3 for supplying the pieces 2a, 2b, the shooter 4 for dispersing and transporting the plastic pieces 2a, 2b supplied by the feeder 3, and the introduction roller 16 for applying a certain pressure to the plastic pieces 2a, 2b and heating them. The transfer roller 17 is composed of a transfer device 18 that heats and melts the surfaces of the plastic pieces 2a and 2b and copies the image onto the transfer roller 17, and the transfer roller 17 rotates, and the plastic films 19a and 19b that are copied and attached to the transfer roller. Infrared lamp 10 for irradiating the infrared ray 10a and infrared transmission spectrum of the plastic films 19a and 19b An infrared detector 11 for detecting the material, an identification device 12 for comparing and comparing with an infrared transmission spectrum of a known plastic, identifying a material, a shooter 9 for conveying plastic pieces 22a and 22b partially copied, and a conveyance The collected plastic pieces 22a and 22b are collected by an air gun 13 that operates in response to a signal from the identification device 12, and collection containers 14a and 14b that collect the plastic pieces 22a and 22b that have been sorted by the air gun 13 and blown off in a predetermined direction. The apparatus 15 includes a remover 20 that peels off the plastic films 19a and 19b attached to the transfer roller 17, and a collection container 21 that collects the peeled plastic films 19a and 19b.

Hereinafter, the operation of the plastic sorting apparatus according to the second embodiment will be described with reference to FIGS.
The to-be-sorted plastic in which the first plastic piece 2a and the second plastic piece 2b of different materials having a thickness of 2 to 3 mm crushed for recycling are mixed is supplied from the feeder 3 to the upper shooter 4. , Distributed and transported. Next, the plastic pieces 2 a and 2 b that have slipped down are heated by the introduction roller 16 and the transfer roller 17 of the transfer device 18, and the plastic pieces 2 a and 2 b are heated by the transfer roller and the surfaces thereof are melted. Affixed as plastic films 19a and 19b. The temperature of the transfer roller 17 is set to 300 ° C. (here, for example, ABS), which is equal to or higher than the higher melting point of the plastic to be selected. Further, when the transfer roller 17 rotates, the plastic films 19a and 19b pass through the plastic films 19a and 19b, and the infrared rays 10a irradiated from the infrared lamp 10 are reflected by the surface of the transfer roller 17, and again the plastic films 19a and 19b. The infrared transmission light 10b that has passed through is detected by the infrared detection device 11, and an infrared transmission spectrum thereof is obtained. The obtained infrared transmission spectrum is compared with the known infrared transmission spectrum of plastic by the identification device 12, the material of the plastic films 19a and 19b irradiated with infrared rays is identified, and the corresponding surface is melted and removed from the plastic. When the pieces 22a and 22b slide down on the shooter 9 in synchronization with the time and position, the pieces 22a and 22b are blown away by the air injected from the air gun 13, and when the plastic piece is the first plastic piece 22a, the pieces are blown off by the air gun 13. If the plastic piece is the second plastic piece 22b and the plastic piece is the second plastic piece 22b, the air gun 13 is thrown into the collection container 14b as it is, and the plastic pieces 2a and 2b are sorted and collected respectively. . On the other hand, the identified plastic films 19 a and 19 b are peeled off by the remover 20 and collected in the collection container 21.

  Since the transfer roller 6 serves to heat and melt the resin and also serves as an infrared reflector, a metal such as aluminum or stainless steel having a mirror-finished surface is preferable. Considering the infrared ray transmission amount of plastic with a small amount of infrared ray transmission, the thickness of the plastic film to be transferred should be 0.1 mm or less, and if it is thin, selection of black plastic with little infrared attenuation and little transmission amount Suitable for. The gap between the introduction roller 16 and the transfer roller 17 may be a gap that presses the plastic pieces 2a and 2b against the transfer roller, and pressure may be applied. Here, since the remover 20 scrapes off the plastic films 19 a and 19 b transferred to the transfer roller 17, a canna-like stainless steel disposed so as to be in contact with the transfer roller 17 is preferable. As the wavelength of infrared rays, a wavelength in the range of 1.0 μm to 2.5 μm can be used as in the first embodiment.

  The temperature of the transfer roller 17 needs to melt the surface of the plastic to be sorted, and is set to be equal to or higher than the maximum melting temperature of the plastic to be sorted. For example, since the melting temperature of ABS is 250 ° C. and the melting temperature of PS and PP (polypropylene) is 150 ° C., when plastics containing ABS are selected, it may be set to 250 ° C. or higher, which is higher than the melting temperature of ABS. .

  As described above, according to the second embodiment of the present invention, the surface of the plastic piece to be selected is melted, and the transfer roller is irradiated with infrared rays in the state of forming a plastic film, thereby transmitting infrared rays like black plastic. Even if the amount is small, the material can be identified with higher accuracy, and the remarkable effect can be obtained that the accuracy of plastic selection can be further improved.

  In the second embodiment, the case where the plastic piece is supplied to the transfer roller by the inclined shooter has been described. However, the plastic piece may be conveyed by the belt conveyor and supplied to the transfer roller, and the same effect is obtained. Play. Further, a plastic film that is irradiated with infrared rays and whose material is identified may be selected and collected.

  In the first and second embodiments of the present invention, the case where an infrared lamp is used as the infrared light source has been described. However, an infrared laser or another light source may be used.

  Moreover, in the figure, the same code | symbol shows the same or an equivalent part.

1 is a schematic perspective view showing a plastic sorting device in Embodiment 1. FIG. FIG. 3 is an enlarged view of a thinning unit portion of the plastic sorting device in the first embodiment. FIG. 6 is a schematic perspective view showing a plastic sorting device in a second embodiment. 6 is an enlarged view of a transfer device section of a plastic sorting device according to Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sorting device 2a, 2b Plastic piece 5 Extruding roller 6 Rolling roller 7 Thinning device 8a, 8b Plastic thin piece 10 Infrared lamp 11 Infrared detector 12 Identification device 13 Air gun 14a, 14b Collection container 15 Collection device 16 Introduction roller 17 Transfer roller 18 Transfer device 19a, 19b Plastic film 20 Remover 21 Recovery container 22a, 22b Plastic piece

Claims (6)

A step of thinning by heat softening and pressing a crushed plastic piece containing plastic with a small amount of infrared transmission ; and
Irradiating the thin plastic flakes with infrared rays;
Detecting an infrared transmission spectrum from the plastic flakes;
Comparing the infrared transmission spectrum with a known plastic infrared transmission spectrum to identify the material of the plastic flakes;
Sorting and collecting the identified plastic flakes for each material;
A plastic sorting method characterized by comprising: 2. The plastic sorting method according to claim 1, wherein the step of thinning the plastic piece is performed by pressing a heated rolling roller. Melting the surface of the crushed plastic piece with a heated transfer roller, and transferring the surface layer of the molten plastic piece to the transfer roller;
Irradiating the transferred plastic film with infrared rays;
Detecting an infrared transmission spectrum from the plastic film;
Comparing the infrared transmission spectrum with the known infrared transmission spectrum of plastic to identify the material of the plastic film;
Selecting and collecting plastic pieces for each material from the identified plastic film material;
A plastic sorting method characterized by comprising: A thinning device for thinning treatment by softening and pressing a crushed plastic piece containing plastic with a small amount of infrared transmission ; and
An infrared light source for irradiating the thin plastic flakes with infrared light;
An infrared detector for detecting an infrared transmission spectrum from the plastic flake;
An identification device for comparing the infrared transmission spectrum with the known infrared transmission spectrum of plastic to identify the material of the plastic flake;
A collection device for sorting and collecting the plastic flakes identified by the identification device according to material;
A plastic sorting device characterized by comprising: 5. The plastic sorting apparatus according to claim 4, wherein the slicing device is by pressing of a heated rolling roller. A transfer device that melts the surface of the crushed plastic piece with a heated transfer roller, and transfers the surface layer of the melted plastic piece to the transfer roller;
An infrared light source for irradiating the transferred plastic film with infrared light;
An infrared detector for detecting an infrared transmission spectrum from the plastic film;
An identification device for comparing the infrared transmission spectrum with a known infrared transmission spectrum of plastic to identify the material of the plastic film;
A collection device for sorting and collecting the plastic pieces according to the material from the identified plastic film material;
A plastic sorting device characterized by comprising:

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