JP5775343B2 - Recycling method for highly foamed plastic moldings - Google Patents

Description

  The present invention is expected to improve quality, cost, and productivity by enabling bulky, highly foamed plastic moldings to be efficiently crushed, reduced in volume, and re-pelletized in the same process of recycling plastic solid molded products. The present invention relates to a method for recycling a highly foamed plastic molding that can be used.

  In general, a highly foamed plastic molded body is bulky, and product stock and conveyance efficiency are poor. However, a used plastic product (solid product) is washed and pulverized as described in, for example, JP-A-2005-103950. It is possible to reduce the volume and to knead the virgin material at a predetermined ratio for recycling. In this technology, washed pulverized products are washed in the process after pulverization, so that deterioration of physical properties due to insufficient removal of dirt and weathering deterioration products will occur, so it is upgraded by mixing with high purity materials (virgin materials) There was a need to do.

Moreover, the said technique cannot be applied as it is to the processing of a highly foamed plastic molding. That is, volume reduction work such as softening, defoaming, and ingot processing is performed as a pretreatment for highly foamed plastic moldings, but ingots must be crushed and pelletized again in order to make raw materials. There was a problem of increased costs. For example, a foamed plastic volume reduction machine disclosed in Japanese Patent Application Laid-Open No. 2004-130234 has been proposed. This is provided with a crushing part and a compression part of foamed plastic, and the crushing part is provided with a horizontal cylinder communicating with a hopper into which the foamed plastic body is charged, and a hollow rotating shaft is passed through the center of the horizontal cylinder. A radial crushing arm is provided at regular intervals, and a crushing plate is provided on the inner wall of the horizontal trunk. Then, the foam sent from the hopper is crushed by a crushing arm and a crushing plate, and the crushed foam is advanced in a certain direction with a screw in the horizontal cylinder, and is pushed into a tapered body to form a rod shape. Compressed into A cooling medium flows through the hollow rotating shaft, controls the temperature rise of the rotating shaft installed in the crushing section, and adheres the melt to the rotating shaft during long-term operation and finally from the volume reducer. It is intended to reduce the variation in hardness of the discharged reduced volume.
JP 2005-103950 A JP 2004-130234 A

  However, the technique disclosed in Japanese Patent Application Laid-Open No. 2004-130234 is theoretically possible, but in reality, it is only intended to store and transport bulky and weightless materials such as highly foamed plastics. The volume reduction operation is a pretreatment to the last, and as described above, there is a problem that the number of steps increases in the normal raw material production step.

  The present invention was created in view of the above-described points that require many steps. The object of the present invention is to make it possible to efficiently and reliably reduce the volume of a highly foamed plastic molded body in one step. The object is to provide a method for recycling foamed plastic moldings.

In order to achieve the above object, the method for recycling the highly foamed plastic body of the present invention, when the highly foamed plastic molded body is put into a cutter compactor part of an extruder with a cutter compactor and pulverized, reduced in volume and pelletized, the homogeneous material plastic solid moldings cleaning ground product relative to the high foam molded plastics, more than 50 percent by weight, and quantified charged with a cutter compactor with extruders metering feeder in which includes the operating signal This product is characterized by adhering the washed and pulverized product as a semi-melted product to a highly foamed plastic molding to form a mixed melt, which can be pelletized while efficiently, uniformly and reliably reducing the volume. did.

  Further, in the recycling method of the highly foamed plastic body according to claim 2, the washed and pulverized product is pulverized while being washed with a large amount of water injected into a pulverizer while being washed with a grime, so that the dirt and weather resistance deteriorate. It is characterized by having the product removed, and it has the same high quality as a high-purity material (virgin material) by removing the dirt on the surface layer and weathering-deteriorated material by washing with rice cake during grinding to restore the initial physical properties. Recycled raw material was constructed.

  Furthermore, in the method for recycling the highly foamed plastic body according to claim 3, the highly foamed plastic molded body is used for a cushioning material or a partition plate used in a plastic container for transportation which is a plastic solid molded product. In the same process of reducing the volume of a plastic container for transportation, the high foamed plastic molded body discharged together with the plastic container for transportation is crushed, volume-reduced, and pelletized. The transportation cost of the molded body can be reduced, and the history of raw materials made into raw materials and environmental assets can be made available to the exhauster.

  According to the present invention, a plastic-washed and pulverized product mixed by 50% or more by weight with respect to a highly foamed plastic molded body has a small particle size, so the temperature rises quickly, so it melts in advance and is highly foamed. Fusing to a plastic molding. Therefore, the highly foamed plastic molded body increases its weight, melts in contact with the pulverized semi-melt, and is sent to the extrusion section of the extruder, so that it has an excellent effect that it can be reliably recycled into pellets.

  Further, according to the invention described in claim 2, the use of the pulverized washing product in which the dirt on the surface layer and the weather-resistant deterioration product are removed by pulverizing while washing and washing even if a large amount of water is poured into the pulverizer is The excellent effect of obtaining the same recycled material as that of high virgin material is obtained.

  Furthermore, according to the invention described in claim 3, in the same process of reducing the volume of the transport plastic container, the highly foamed plastic molded body discharged together with the transport plastic container is crushed, reduced in volume, and pelletized. Therefore, it has an excellent effect that the history of the recycled raw material and the environmental asset can be made available to the discharger.

  Next, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic front sectional view of a recycling apparatus used in the present invention, FIG. 2 is a schematic plan sectional view of the apparatus, and FIG. 3 is an enlarged view of a quantitative feeder.

  The apparatus 1 used in the present invention is one in which a highly foamed plastic molded body 4 is placed in a drum 3 having a disc 2 having a carter blade at the bottom, and pulverized, mixed, heated and reduced in volume. A highly foamed plastic molded body 4 can be transported and fed into the drum 3 by a conveyor belt 5.

  The highly foamed plastic molded body 4 is widely used as a cushioning material and a partitioning material when transporting semi-finished products and finished products. Since this is designed for a semi-finished product or a finished product, it is discarded or recycled because its use is limited. However, when it is discarded or recycled, it is bulky and expensive. There are many products of polystyrene (PS), polypropylene (PP), and polyethylene (PE) as representatives of the highly foamed plastic molding 4. The technology of the present invention is particularly effective for increasing the recycling efficiency of the highly foamed plastic body molding 4 that is 10 times or more bulky and inferior in repellency.

  The drum 3 has a cylindrical shape, and its top is open. In the center of the bottom, the rotary shaft 6 penetrates in a liquid-tight manner. The lower end of the rotary shaft 6 is connected to the external motor 7 of the drum 3, and the upper part is coupled so as to drive the disk 2 having the carter blade.

  The driving of the conveyor belt 5 is interlocked with the melting (processing) load of the drum 3. The conveyor belt 5 is provided with blades 5 ′ on which a highly foamed plastic molding (within the diameter of the top of the drum) 4 is placed and moored at equal intervals. Thus, in the lower part 5a, the highly foamed plastic molded body 4 placed manually or automatically is supplied from the upper part 5b into the drum 3 as indicated by an arrow A.

  Above the conveyor belt 5 on the lower 5a side, a quantitative feeder 8 is installed on an installation table 8a. The fixed quantity feeder 8 is taken out from a storage bag (suspended from the ceiling or the like) 10 of the plastic solid product washed and pulverized product 9 and received by the hopper 8b, and the conveyor belt 5 is fed at a constant rate through the screw 8c. Supply is possible between the blades 5 'and 5' as indicated by the broken line. That is, as shown in FIG. 3, the drive unit 5 </ b> K of the conveyor belt 5 is interlocked with the melting load of the drum 3 that is pulverized, melted, and reduced in volume. In other words, when the load (weight) in the drum 3 decreases, the drive unit 5K of the conveyor belt 5 operates to supply the highly foamed plastic molded body 4, and the drum is in a sufficient state (within the necessary load). ) Is stopped. In addition, the drive unit 8d of the fixed quantity feeder 8 crushes, melts, and reduces the inside of the drum 3 for the purpose of supplying the cleaning and pulverized product 9 in the hopper 8b into the drum at a constant rate by the action of the screw 8c. It is designed to be linked to the melting load to be stored. Therefore, the installation of the quantitative feeder 8 enables the automatic and simultaneous quantitative charging of a plurality of materials in one process.

  As the washed and pulverized product 9, for example, it is recycled (recycled) into a product of the same color and shape as a used plastic product (solid product) such as a plastic container (return box) or plastic pallet (loading tool) used by a certain manufacturer. In the delivery process, the original product is crushed with a large amount of water injected into the pulverizer while washing with rice bran to remove dirt and weather-resistant products, and has a size of 8 to 20 mm. That is, the washed and pulverized product 9 is substantially the same as a high-purity virgin material, and can be upgraded to obtain a high-quality recycled raw material. Of course, the washed and pulverized product 9 is made of the same material as the highly foamed plastic molding 4 or a compatible material.

  Since the high-foamed plastic molded body 4 is often used in the plastic container (return box), the plastic container is recycled (recycled) into a product of the same color and shape in the same process. If the highly foamed plastic molding is crushed, reduced, or pelletized, that is, as in the case of the present applicant, the plastic container is pulverized, reduced, pelletized, and the highly foamed plastic molded body is crushed, reduced, pelleted. The recycling bases for recycling are common, and the highly foamed plastic moldings can be carried using the space of the plastic container (return box), so that the transportation costs can be reduced and the recycling materials for the exhausters can be reduced. Enables history management and environmental assetization.

  A cutting blade 2 ′ is fixedly provided on the disk 2. When the bulky high-foamed plastic molded body 4 and the washed pulverized product 9 are put into the drum 3 by the conveyor belt 5, Is reliably pulverized and stirred by the action of the disk 2 provided with the cutting blade 2 ', and the temperature is raised by frictional heat between the respective resins. Due to this temperature rise, the semi-melted product 11 of the washed and pulverized product 9 adheres to the bulky highly foamed plastic molding 4 to increase the weight. Thus, the highly foamed plastic molding 4 is stirred and rubbed together with the washed pulverized product 9 while moving in the upper space in the drum 3 as indicated by arrows B and C, and is melted to flow as a mixed melt. It is supplied to the extruder 13 from the outlet 12.

  The mixed melt is reliably fed into the extruder 13 through the outlet 12 by the centrifugal force generated by the operation of the disk 2 rotating in the drum 3. In the cutter compactor (drum) 3, as described above, the temperature rises due to frictional heat between the resins, and thus no heater is installed. Of course, there is a temperature control value that controls the rise of the resin temperature too much. For example, when the set temperature of the cutter compactor is exceeded, the shower unit (not shown) reacts (water injection) to keep the temperature. The injected water evaporates and is discharged from the open top of the drum 3.

The mixed melt that has entered the extruder 13 from the discharge port 12 is kneaded by the screw 14 and removed from the vent port 16 provided in the cylinder 15 of the extruder 13 by the vacuum pump 18 through the pipe 17. Foamed. The kneaded and defoamed mixed melt is extruded as a linear product 20 through a die 19 of an extruder 13, cut into a granule by a pelletizer 22 through a cooler 21, and stored in a storage tank 23 as a recycled pellet raw material. The In addition, the linear product 20 extruded through the die 19 of the extruder 13 may be cut into particles by a hot cutting method using a rotary blade to be a recycled pellet raw material.

  Next, the Example about the extrusion amount of an extruder is shown. First, a 40-fold foamed polypropylene molded product and a polypropylene solid washed and pulverized product are put into a cutter compactor section (drum 3) of an extruder with a cutter compactor by means of a conveyor belt 5, and by the action of a disk 2 having a carter blade. Grind and stir. At this time, the temperature rises to 110 ° C due to the frictional heat between the resins, and the small-diameter washed and pulverized product first becomes a semi-molten product and adheres to the high-foamed polyethylene molded body. The mixed melt is supplied to the extruder 13 from the outlet 12 and is extruded as a linear product 20 through the die 19 of the extruder 13.

  The washed and pulverized product of the polypropylene solid is 40%, 50%, 60%, 80% of the amount of the polypropylene molded body expanded by 40 times, and the cutter compactor portion of the extruder with a cutter compactor ( A fixed amount was put into the drum 3) and extruded as a linear product 20 through the die 19 of the extruder 13. The extrusion amount at this time is shown in the following table.

[table]
Highly foamed polypropylene molding (foaming ratio 40 times) 20 40 50 60
Washed and pulverized product of polypropylene solid (% by weight) 80 60 50 40
Extrusion amount (Kg / h) 260 230 200 160

  As can be seen from the above table, the plastic-washed and pulverized product 9 is preferably 50% or more by weight with respect to the amount of the highly foamed plastic molded body 4. That is, if the weight ratio is less than 50%, the profitability is poor. If the weight ratio is 50% or more, mass production can be efficiently performed. Although there is no upper limit in terms of quality, it is preferable not to exceed 65% in terms of profitability.

  In the recycling method of the present application, the high-foamed plastic molding and the plastic washed and pulverized product are simultaneously put into a cutter compactor (drum), and the smaller particle size (washed and pulverized product) is melted first by frictional heat between resins. However, the highly foamed plastic molding is brought into contact with the melt while being crushed, melted, and sent to the extruder through the outlet. This can be used in the same process for volume reduction of used plastic products, and the industrial applicability is extremely high.

It is a schematic front sectional view of a recycling apparatus used in the present invention. It is a schematic plane sectional view of a recycling apparatus used in the present invention. It is an enlarged view of a fixed quantity feeder part.

DESCRIPTION OF SYMBOLS 1 Apparatus used for this application method 2 Disc 2 'Cutting blade 3 Cutter compactor (drum)
4 Highly foamed plastic molding 5 Conveyor belt 5K Driving machine 5a Lower 5b Upper 5 'Blade 6 Rotating shaft 7 Motor 8 Metering feeder 8a Installation stand 8b Hopper 8c Screw 8d Driving machine 9 Plastic cleaning pulverized product 10 Container (bag)
DESCRIPTION OF SYMBOLS 11 Semi-melt 12 Outlet 13 Extruder 14 Screw 15 Cylinder 16 Vent port 17 Pipe 18 Vacuum pump 19 Dice 20 Linear goods 21 Cooler 22 Pelletizer 23 Storage tank

Claims (3)

When the highly foamed plastic molding is put into the cutter compactor section of an extruder with a cutter compactor and pulverized, volume-reduced, or pelletized, previously washed and pulverized products of plastic solid molded products of the same material are used in the above-mentioned highly foamed plastic molding. 50% or more by weight of the body is quantitatively charged with a quantitative feeder linked to the operation signal of the extruder with a cutter compactor, and the washed pulverized product is adhered to the highly foamed plastic molded body as a semi-melt, A method for recycling a highly foamed plastic molding, characterized in that it is a mixed melt .   The washed and pulverized product is obtained by pulverizing a used plastic product while washing and washing with a large amount of water injected into a pulverizer to remove dirt and weather-resistant products. Recycling method of the highly foamed plastic molding described in 1.   2. The highly foamed plastic according to claim 1, wherein the highly foamed plastic molded body is used for a cushioning material or a partition plate used in a plastic container for transportation which is a plastic solid molded product. Recycling method of molded products.

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