JP7285038B1 - Waste plastic recycling system - Google Patents

Abstract

A waste plastic recycling system capable of sorting pellets according to glass fiber content is provided. A granulator that melts and kneads waste plastic containing glass fiber and then granulates it into pellet pieces of the same shape and size; a metal detector that removes pellet pieces containing non-magnetic material by passing the pellet pieces between the transmitting coil and the receiving coil and changing the voltage of the receiving coil, and X-ray transmission of the pellet pieces The amount threshold can be set, and it is arranged downstream of the magnetic force sorting device and the metal detector, and sorts out pellet pieces with an X-ray transmission amount of the pellet pieces equal to or greater than the threshold value and pellet pieces with an X-ray transmission amount less than the threshold value. and a line inspection device, and the pellet pieces below the threshold value are used for the recycled plastic raw material. [Selection drawing] Fig. 2

Description

The present invention relates to a recycling system for reusing plastics used in automobile parts such as bumpers and instrument panels, transportation parts such as transportation pallets, returnable boxes and beer cases, and furniture such as doors and beds. It relates to a recycling system for reusing plastics containing glass fibers for retention.

Resin bumpers, which are automobile parts, are removed from automobiles and recycled when the automobiles are scrapped. Patent Document 1 discloses a method for using this resin bumper as a recycled resin material. In this method, coarsely crushed bumpers are subjected to a sorting process using the air force selection method and the water specific gravity sorting method to remove foreign matter, then extruded while being melted and kneaded in a twin-screw extruder, and the extruded molded product is cut. It is cut by machine and pelletized.

However, there is a problem that it is difficult to use the pellets obtained by the method described in Patent Document 1 for recycling bumpers. Bumpers contain glass fibers in a base material resin such as PP (polypropylene) or polyamide to maintain strength. The strength depends on the glass fiber content, and in order to maintain the strength of the bumper, it is necessary to use pellets containing a certain amount of glass fiber as the raw material for the recycled bumper. The method of Patent Document 1 only melts and kneads materials to form pellets, and it is unclear how much glass fiber is contained in the obtained pellets. For this reason, bumpers recycled using the pellets obtained by the method of Patent Document 1 may not be able to maintain a predetermined strength.

For this reason, it is conceivable to measure the glass fiber content in each pellet and sort the pellets according to the content, but measuring the glass fiber content of each pellet is very troublesome. A new problem arises that cannot be mass-processed. The above applies not only to automobile bumpers, but also to vehicle instrument panels, transportation pallets, returnable boxes, beer cases, and other transportation materials, furniture such as doors and beds, and waste plastics such as PET bottles and packaging plastic bags. But it's the same problem.

The present applicant has proposed a system for sorting pellet pieces of the same shape and size with a specific gravity sorter, as shown in Patent Document 2. According to this, only the selected pellet pieces of a certain weight can be used as regenerated raw materials, and parts having the same strength as the original parts can be regenerated. The present invention proposes another sorting system different from the gravity sorter for pellet pieces.

Japanese Unexamined Patent Application Publication No. 2011-20298 Japanese Patent No. 7152083

It is an object of the present invention to sort out acceptable products and unacceptable products according to the content of glass fibers in the waste plastic when recycling waste plastics such as bumpers of scrapped automobiles into the original parts. To provide a waste plastic recycling system capable of reliably regenerating parts having the same strength as the original parts.

A waste plastic recycling system according to the present invention comprises a granulator that melts and kneads waste plastic containing glass fibers and then granulates the pellet pieces into pellet pieces of the same shape and size; A magnetic force sorting device that sorts pellet pieces and pellet pieces that do not contain a magnetic substance by the magnetic force of a permanent magnet and removes pellet pieces that contain a magnetic substance; A metal detector that removes pellet pieces containing non-magnetic material by changing the voltage of the coil, and a threshold value for the amount of X-ray transmission of the pellet pieces can be set, downstream of the magnetic sorting device and the metal detector. an X-ray inspection device arranged on the side and sorting out pellet pieces having an X-ray transmission amount equal to or greater than the threshold value and pellet pieces having an X-ray transmission amount less than the threshold value when the pellet pieces are irradiated with X-rays, and is less than the threshold value is used as a recycled plastic raw material.

A crushing and pulverizing device for crushing and pulverizing the waste plastic is arranged upstream of the granulator.

The magnetic sorting device is arranged upstream of the metal detecting device.

A coating film removing device for removing the coating film of the waste plastic is disposed upstream of the granulator and downstream of the crushing and pulverizing device.

According to the waste plastic recycling system of the present invention, pellet pieces of the same shape and size are granulated by a granulator, and then pellet pieces containing magnetic metal are removed by a magnetic separator, Furthermore, a metal detector removes pellet pieces containing non-magnetic metal. are sorted out, and only pellet pieces below the threshold value are used as regenerated raw materials for the original parts, so parts having the same strength as the original parts can be reliably regenerated. That is, since the pellet pieces mixed with magnetic and non-magnetic metals are removed by the magnetic sorting device and the metal detector, the amount of glass fiber contained in the pellet pieces is determined as X Since it is determined by a line inspection device, more accurate selection is possible.

Since the crushing and pulverizing device for crushing and pulverizing the waste plastic is arranged upstream of the granulator, the waste plastic can be melted in the granulator after being crushed, thereby facilitating granulation of the waste plastic.

Since the magnetic force sorting device is arranged upstream of the metal detector, even if a large number of magnetic metal pieces are mixed, the magnetic metal pieces can be removed in advance, thereby reducing the load on the metal detector. That is, the non-magnetic metal can be removed without the metal detector being disturbed by the magnetic metal piece.

Since the coating film removing device for removing the coating film of the waste plastic is arranged upstream of the granulator and downstream of the crushing and pulverizing device, undesirable paint pieces can be removed.

1 is a flowchart showing processing of a waste plastic recycling system according to the present invention; 1 is an overall configuration diagram of a waste plastic recycling system according to the present invention; FIG. FIG. 4 is a diagram showing an example of signals of the metal detector; It is a figure which shows the signal example of an X-ray inspection apparatus. FIG. 4 is a cross-sectional view of a waste bumper; 1 is a structural diagram of a coating film removing device; FIG.

A waste plastic recycling system according to the present invention will be described with reference to the drawings. In the following embodiments, a bumper separated from a scrap car as waste plastic will be described as an example.

FIG. 1 is a flow chart showing the processing of the waste plastic recycling system according to the present invention, and FIGS. 2 and 3 show the specific structure of the recycling system according to the flow chart. As shown in FIG. 1, the recycling system includes a crushing and pulverizing stage 100, a coating film removing stage 110, a granulating stage 120, a magnetic material-containing pellet removing stage 130, and a non-magnetic material-containing pellet piece. It comprises a step of removing 140 and a step of sorting 150 the pellet pieces according to glass fiber content.

The crushing-grinding stage 100 uses a crushing-grinding device 50 (see FIG. 2). In the crushing and crushing device 50 , the waste bumper 1 is crushed into pieces of a predetermined size, and then crushed into smaller pieces to obtain waste bumper pieces (waste plastic pieces) 2 .

Granulation stage 120 uses a granulator 53 (see FIG. 2). In the granulator 51, the waste bumper pieces 2 are melted and extruded into pellet pieces 3 of the same shape and size. In the granulation stage 120 , pellet pieces 3 are granulated by melting and extruding the waste bumper pieces 2 by, for example, a screw-type extruder 5 having a heater 4 . In this form, it is cut to the same length by a cutter 6 when it is taken out from the outlet of the screw type extruder 5 . As a result, it is possible to continuously granulate pellet pieces 3 of the same shape and size having the same outer shape along the shape of the outlet and the same length.

In step 130 of removing pellets containing magnetic material, pellet pieces 3 containing magnetic metal are removed by magnetic force sorting device 90. In step 140 of removing pellet pieces containing non-magnetic material, metal detection device 91 is used. removes pellet pieces 3 containing non-magnetic metal.

The sorting step 150 of the pellet pieces according to glass fiber content uses an X-ray inspection device 92 (see FIG. 2). The X-ray inspection device 92 is arranged downstream of the magnetic force sorting device 90 and the metal detection device 91 . The X-ray inspection device 92 can set the threshold value of the amount of X-ray transmission of the pellet piece 3 . When the pellet pieces 3 are irradiated with X-rays, the pellet pieces 3 having an X-ray transmission amount equal to or greater than the threshold value and the pellet pieces 3 having an X-ray transmission amount less than the threshold value are selected, and the pellet pieces having an X-ray transmission amount less than the threshold value are used as recycled plastic raw materials.

The X-ray inspection device 92 is supplied with pellet pieces 3 of the same shape and size, and measures the X-ray transmission amount of the pellet pieces 3 of the same shape and size. Also, the threshold value is set based on the amount of X-ray transmission corresponding to the glass fiber content that can be used for bumper regeneration. The pellet pieces having an X-ray transmission amount equal to or higher than the threshold value are pellet pieces having a large X-ray transmission amount and containing little glass fiber, and are pellet pieces that are not suitable for bumper regeneration. The pellet pieces having an X-ray transmission amount less than the threshold value are pellet pieces having a low X-ray transmission amount and containing a large amount of glass fiber, and can be used for bumper regeneration.

In the present invention, of the pellet pieces granulated to have the same shape and size, only the pellet pieces having the X-ray transmission amount less than the threshold value are used to regenerate the original bumper. The strength of the bumper can be played back. In the present invention, since it is not necessary to measure the glass fiber content of each pellet piece, mass processing is possible, and a bumper having the strength of the original bumper can be easily regenerated.

The paint film removal step 110 is the step of removing the paint film, if any, on the bumper surface. An organic solvent having dissolving power for the paint is used to remove the paint film. Note that the amount of the coating film is extremely small with respect to the entire bumper, and since the coating film is kneaded into the resin material during granulation in the granulation step 120, there may be no problem in practical use. For this reason, the coating removal step 130 may be omitted.

FIG. 2 is an overall configuration diagram of a waste plastic recycling system 200 according to the present invention. A waste damper 1 removed from an automobile is crushed roughly into pieces using a crusher 50, and then crushed into smaller pieces to produce waste bumper pieces (waste plastic pieces) 2. do. More specifically, it is roughly cut by a crusher 7 into plastic pieces of approximately 10 cm, and then finely cut by a crusher 8 into waste bumper pieces (waste plastic pieces) 2 of approximately 1 cm.

Subsequently, the waste bumper pieces (waste plastic pieces) 2 are put into the granulator 52 . The granulator 52 melts the thrown-in waste bumper (waste plastic pieces) 2 by means of a screw-type extruder 5 equipped with a heater 4 and extrudes the waste bumpers (waste plastic pieces) 2 rightward in FIG. A cutter 6 cuts the rod-shaped member extruded from the outlet to a given length to produce pellet pieces 3 of the same shape and size. The pellet pieces 3 are subsequently introduced into a magnetic force sorting device 90 and a metal detecting device 91 following this.

The magnetic sorting device 90 and the metal detector 91 are housed in one housing. A metal detector 91 is arranged downstream of the magnetic sorter 90 . The magnetic force sorting device 90 has a structure in which the shell 25 is rotated around the permanent magnet 24 . A pellet piece 3 is dropped from above toward the shell 25. - 特許庁The structure is not limited to this, and a structure in which the permanent magnet 24 is incorporated at one end of the belt conveyor and the pellet pieces 3 are conveyed by the belt conveyor may be employed. When the pellet pieces 3 containing magnetic material pass through the shell 25 made of a cylindrical thin metal plate, the magnetic force of the permanent magnet 24 changes the flight curve. It is separated by passing through the inside (left side). The non-defective pellet pieces 3 containing no magnetic material are not affected by the permanent magnet 24, so they pass through the outside (right side) of the sorting flap 23 and fall.

The permanent magnet 24 is formed by alternately stacking discs and yokes serving as permanent magnets, and the discs are stacked so that N and S face each other. The overlapping length is about 50 cm. In this embodiment, the permanent magnet 24 is semicylindrical. As a result, magnetic lines of force can be generated over a wide range in the upper right direction of the shell 25 . The permanent magnet 24 is attached to the center shaft 26 together with the balancer so as to face the upper right direction and does not rotate. As the central shaft 26 rotates, the shell 25 rotates.

A speed control unit 21 is provided which can arbitrarily change the rotation speed of the shell 25 . again,
The sorting flap 27 is provided with a slide mechanism 22 that not only allows the angle to be freely changed, but also makes it slidable. These make it possible to finely adjust the position of the tip of the sorting flap 27 on the trajectory of the pellet pieces 3 .

The metal detector 91 separates the pellet pieces 3 containing non-magnetic metal pieces such as aluminum pieces. The metal detector 91 is provided with a transmission coil 91a and a reception coil 91b. When the pellet 3 containing non-magnetic material passes through, the voltage of the reception coil 91b changes. By actuating the sorting flap 28 and changing the angle, the pellet pieces 3 containing the non-magnetic material are separated.

In the X-ray inspection device 92 , the pellet pieces 3 are sent to the belt conveyor 30 . The X-ray tube 31 and the line sensor 32 determine whether the pellet piece 3 on the belt conveyor 30 is an image with a predetermined threshold value. As a result, the pellet pieces 3 whose X-ray transmission amount is greater than or equal to the threshold value and those whose X-ray transmission amount is less than the threshold value are sorted out. It can be divided into pellet pieces with an X-ray transmission amount greater than or equal to the threshold, that is, pellet pieces that do not contain much glass fiber, and pellet pieces 3 with an X-ray transmission amount that is less than the threshold, that is, pellet pieces 3 that contain a large amount of glass fiber. Then, the pellet pieces 3 below the threshold value are used as recycled plastic raw materials. Here, the amount of glass fiber contained in the pellet piece 3 is determined by the density of the image picked up by the X-ray inspection device 92 . Based on this determination, the sorting flap 29 is operated to change the angle, thereby separating the pellet pieces 3 containing a large amount of glass fibers and the pellet pieces 3 containing a small amount of glass fibers. The discharge box 9 contains the pellet pieces 3 above the threshold and the discharge box 10 contains the pellet pieces 3 below the threshold.

FIG. 3 is a diagram showing an example of signals from the metal detector 91. As shown in FIG. As shown in FIG. 3, if the pellet pieces 3 are not passed through the magnetic sorting device 90, a large number of signals are generated, and the performance of detecting pellet pieces containing non-magnetic material is lowered. When the pellet pieces 3 are passed through the metal detector 91 after passing through the magnetic sorting device 90, the signal indicating the pellet pieces containing non-magnetic material can be accurately detected.

FIG. 4 is a diagram showing an example of signals from the X-ray inspection device 95. As shown in FIG. As shown in FIG. 4, if the pellet pieces 3 are passed without passing through the magnetic sorting device 90 and the metal detector 91, a large number of signals due to the foreign matter are generated and the performance of the X-ray inspection device 95 is deteriorated. When the pellet pieces 3 are passed through the magnetic force sorting device 90 and the metal detector 91 and then put into the X-ray inspection device 95, noise signals are reduced and the captured image can be accurately judged.

FIG. 5 is a cross-sectional view of an example of the waste bumper 1. As shown in FIG. The base material 18 of the bumper is generally made of thermoplastic polypropylene mixed with glass fibers. A thermoplastic resin primer 17 is applied to the surface of the substrate 18, and a thermosetting resin coating 16 is formed thereon. As an example, if the thickness of the substrate 18 is 5 mm, the thickness of the primer 17 can be 10 μm and the thickness of the coating 16 can be 40 μm. Glass fibers are mixed into the substrate 18 .

FIG. 6 is a structural diagram when the coating film removing device 51 is incorporated. The coating film removing device 51 is arranged between the crushing and pulverizing device 50 and the granulating device 52 . Even if the coating film is pulverized, it may affect the quality of the pellet pieces 3 , and can be removed by the coating film removing device 51 . The coating film removing device 51 is equipped with a stirring rod 20 inside the drum 19, and the waste bumper pieces (waste plastic pieces) 2 are thrown in and stirred. A coating stripper is also introduced into the drum 19 to facilitate stripping of the coating.

In the above embodiments, a recycling system using waste plastics from automobile bumpers has been described. The same can be applied to furniture such as doors and beds, and waste plastics such as PET bottles and packaging plastic bags.

In the present invention, pellet pieces of the same shape and size are produced, and only pellet pieces of which the X-ray transmission amount of the pellet pieces of the same shape and size is less than the threshold value are used as recycled plastic raw materials, so that the strength of the recycled plastic is increased. can hold. Therefore, it is suitable as a recycling system for reusing plastics containing glass fibers.

1 waste bumper 2 waste plastic piece (waste bumper piece)
3 pellet piece 4 heater 5 screw extruder 6 cutter 7 crusher 8 crusher 9 discharge box (items with a certain weight or more)
10 Discharge box (things under a certain weight)
16 Coating film 17 Primer 18 Base material 19 Drum 20 Stirring bar 21 Speed control part 22 Slide mechanism 23 Guide 24 Permanent magnet 25 Shell 26 Center shaft 27 Sorting flap 28 Sorting flap 29 Sorting flap 30 Belt conveyor 31 X-ray tube 32 Line sensor 33 Feeder 50 Crushing and pulverizing device 51 Coating film removing device 52 Granulating device 90 Magnetic force sorting device 91 Metal detector 92 X-ray inspection device 200 Waste plastic recycling system S100 Crushing and pulverizing stage S110 Granulating stage S120 Coating film removing stage S130 Magnetic substance content Step of removing pellet pieces S140 Step of removing pellet pieces containing non-magnetic material S150 Step of sorting pellet pieces according to glass fiber content

Claims (4)

a granulator for melting and kneading waste plastics containing glass fibers and then granulating them into pellet pieces of the same shape and size;
A magnetic force sorting device that is supplied with the pellet pieces, sorts the pellet pieces containing the magnetic substance and the pellet pieces that do not contain the magnetic substance by the magnetic force of the permanent magnet, and removes the pellet pieces containing the magnetic substance;
a metal detector that passes the pellet pieces between a transmission coil and a reception coil and removes the pellet pieces containing non-magnetic material by changing the voltage of the reception coil;
A threshold value for the amount of X-ray transmission of the pellet pieces can be set, and is arranged downstream of the magnetic sorting device and the metal detection device, and the X-ray transmission amount when the pellet pieces are irradiated with X-rays is An X-ray inspection device that sorts out pellet pieces above the threshold and pellet pieces below the threshold,
A recycling system for waste plastic, characterized in that the pellet pieces below the threshold value are used as recycled plastic raw materials. 2. The waste plastic recycling system according to claim 1, wherein a crushing and pulverizing device for crushing and pulverizing the waste plastic is disposed upstream of the granulator. 3. The waste plastic recycling system according to claim 1, wherein the magnetic sorter is arranged upstream of the metal detector. 3. The recycling of waste plastics according to claim 2, wherein a coating film removing device for removing the coating film of the waste plastics is disposed upstream of the granulator and downstream of the crushing and crushing device. system.

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