JP5480848B2 - Recycling method and equipment for market recovered foamed plastic containers - Google Patents

Description

  The present invention relates to a method and an apparatus for recycling a foamed resin sheet molded container collected from the market as a recycled resin.

  Foamed resin containers are widely used in the market as food containers or trays. At present, how to treat used foamed resin containers is a social issue. Return the foamed resin containers collected from the market back to the resin for raw materials, that is, as recycled resin. Several proposals have been made regarding recycling.

  Patent Document 1 describes a recycling apparatus in which foamed polystyrene is melted in an organic solvent such as limonene, and then the organic solvent is vaporized and separated to obtain a pelletized recycled resin. In Patent Document 2, in order to recycle PET bottles that are not foamed, PET is pulverized into flakes, the flakes are washed using hot washing water, etc., and then rinsed to perform a rinsing step. A method and an apparatus for cleaning recycled PET flakes are described in which the passed PET flakes are drained and subjected to a hot air drying process using a hot air dryer.

JP 2005-179466 A JP 2002-320932 A

  In the recycling method described in Patent Document 1, since an organic solvent capable of easily dissolving the polystyrene foam is used, it is necessary to remove the organic solvent contained in the pellets obtained by recycling and to recover the removed organic solvent. Removal of the organic solvent requires ancillary equipment such as a large-scale vacuum device, which requires a lot of energy and time, and the recycled resin is also required to reduce the organic solvent to an allowable concentration of less than 50 ppm, for example. It is done. In the method and apparatus described in Patent Document 2, since no organic solvent is used, energy and time required for removing the organic solvent are not required, but it is necessary to drain the PET flakes that have undergone the rinsing process and dry them with hot air. It needs a lot of energy for hot air drying.

  For this reason, in order to obtain a recycled resin that can be used as a raw material resin from a resin product that has been used once, it takes a lot of energy and time, and the burden on the environment increases. Yes. Therefore, there is a need for a spent resin recycling method and apparatus that can obtain a recycled resin with less energy and in a shorter time.

  An object of the present invention is to provide a resin recycling method and apparatus capable of answering the above requirements. More specifically, a foamed resin sheet molded container recovered from the market can be obtained with less energy and in a short time. It is an object to provide a method and an apparatus that can be recycled as recycled resin.

  As a result of intensive investigations to solve the above problems, the present inventors have found that resin products, particularly resin products obtained by thermoforming foamed resin sheets, are crushed and then immersed in water for the purpose of washing or the like. In this case, it has been found that the washing water enters the inside of the pulverized material from the fracture surface and the water content becomes high. On the other hand, it has also been found that water adhering to the surface can be removed in a short time by physical dehydration such as centrifugation without performing a heat drying treatment.

  In addition, in order to obtain a recycled resin from a foamed resin product, it is necessary to put a pulverized product of the foamed resin product into a melt extruder, reduce the volume and melt and pelletize it. At that time, if the water content of the pulverized product to be charged is large, the molten resin cannot be extruded from the melt extruder in a stable state, and a high-quality recycled resin cannot be obtained. It has been found that the water content of the pulverized resin is preferably about 18 wt% or less, even if it varies depending on the deaeration performance of the melt extruder used.

  As described above, in the case of a pulverized product of a resin product obtained by thermoforming a foamed resin sheet, moisture adhering to the surface by a cleaning process or the like can be removed in a short time by a physical dehydration process. Therefore, the products collected from the market are processed in two stages, the first coarse pulverization and the next fine pulverization. The coarsely pulverized state is washed using water, alkali or soap, After dehydration, it is pulverized and put into a melt extruder. At that time, by setting the size of the coarsely pulverized product within a predetermined range, the amount of moisture entering the pulverized product from the fracture surface per fixed volume of the coarsely pulverized product can be kept low. Therefore, even if the coarsely pulverized product after washing is not subjected to heat drying treatment, only physical dehydration treatment such as centrifugal separation is performed, and there is no problem in putting it into the melt extruder. It has also been found that reducing the water content can be realized in a short time with less energy. The present invention has been made based on the above new findings.

That is, a first invention of the present application is a method for recycling a foamed resin sheet molded container recovered from the market as a recycled resin, and the market recovered foamed resin container is roughly roughened to an average size of about 7 to 300 cm ² . A step of pulverizing into a coarsely pulverized product, a step of washing the coarsely pulverized product with water, a step of washing the coarsely pulverized product after the water washing with hot water of about 30 to 70 ° C. containing alkali or soap, The step of reducing the water content to about 18 wt% or less by physical dehydration without heating and drying the coarsely pulverized product after washing with hot water, and the average size of the coarsely pulverized product dehydrated to about 18 wt% or less. The method includes at least a step of finely pulverizing to ² to 6 cm ² to obtain a finely pulverized product, and a step of reducing the volume and melting the finely pulverized product using a melt extruder to obtain a regenerated molten resin. City Is a method for recycling recovered foamed resin container.

The second invention of the present application is an apparatus for recycling a foamed resin sheet molded container recovered from the market as a recycled resin, and the market recovered foamed resin container is roughly roughened to an average size of about 7 to 300 cm ² . A coarse pulverizer for pulverizing into a coarsely pulverized product, a water washer for washing the produced coarsely pulverized product with water, and the roughly pulverized product after the water washing contains an alkali or soap approximately 30- A hot water washer for washing with warm water of 70 ° C., and a dehydrator capable of reducing the water content to about 18 wt% or less by physical dehydration without heating and drying the coarsely pulverized product after the hot water washing , The dehydrated coarsely pulverized product is finely pulverized to an average size of about 0.2 to 6 cm ² to obtain a finely pulverized product, and the finely pulverized product is reduced in volume and melted to be regenerated and melted. A melt extruder to make resin, Also it includes as a recycling device for market recovery foamed resin container according to claim.

  As described above, in order to recycle a market-recovered foamed resin container as a recycled resin, washing with water is necessary, and in order to obtain a molten resin using a melt extruder, much of the water used for washing is pulverized. Although it is necessary to remove it from the object, according to the present invention, it is possible to remove this moisture only by a physical dehydration process without performing a heat drying process such as hot air drying. Therefore, both the reduction of energy used and the reduction of processing time are possible, and the recycling processing method and apparatus can reduce the burden on the environment.

  In the present invention, in the physical dehydration treatment such as centrifugation, the moisture adhering to the surface of the coarsely pulverized product can be removed in a short time, but it is difficult to remove the moisture that has entered inside from the pulverized surface. Therefore, the water content per unit volume (for example, 100 L) of the coarsely pulverized product after the dehydration process (the total amount of water that has entered inside from the pulverized surface of each coarsely pulverized product) However, when passing through, it is necessary to keep it to be approximately equal to or less than the amount that can be discharged as vapor from the vent port.

In the experiments of the present inventors, when using a general melt extruder conventionally used for the recycling process of foamed resin, the coarsely pulverized product of the market recovered foamed resin container is smaller than the average size of about 7 cm ^2. When pulverized to a size, the total of the pulverized surfaces per unit volume of the coarsely pulverized product was too large, exceeding the ability to be discharged as vapor from the vent port, and a regenerated resin could not be obtained stably. In addition, when the average size of the coarsely pulverized product in the market-recovered foamed resin container is larger than 300 cm ² , there is a problem that a pipe is clogged when the coarsely pulverized product is transferred to the next process. Therefore, in the present invention, it is a necessary invention constituent to roughly pulverize the market-collected foamed resin container to an average size of approximately 7 to 300 cm ² to obtain a coarsely pulverized product.

  Some foamed resin sheet-molded containers recovered from the market still have dirt on the surface. Removing the dirt is a process necessary to obtain a high-quality recycled resin. In the present invention, washing the coarsely pulverized product with water is an invention constituent necessary for removing protein stains. Washing with is an invention constituent necessary for removing the dirt of oil and fat.

  As described above, the pulverized foam resin product is charged into a melt extruder to reduce the volume and melt, and in order to stably extrude from the melt extruder as a high-quality recycled resin, the water content in the melt resin is It should be as low as possible. For this purpose, the water content of the pulverized resin when it is charged into the melt extruder is at most 18 wt%, so that almost the entire amount can be discharged from the vent port. Therefore, in the present invention, it is necessary to reduce the water content to about 18 wt% or less in a short time and with less energy by physical dehydration without heating and drying the coarsely pulverized product after washing with hot water. Matters.

In a normal melt extruder, in order to satisfactorily reduce the volume and melt the pulverized product of the charged foamed resin, the size of the pulverized product is desirably about 0.2 to ⁶ cm ² on average. Therefore, in the present invention, it is necessary to constitute the finely pulverized product by finely pulverizing the coarsely pulverized product dehydrated to approximately 18 wt% or less to an average size of approximately 0.2 to 6 cm ^2. .

  In the present invention, the finely pulverized product is put into a melt extruder and subjected to volume reduction and melting treatment as in the conventional case. In the process, as described above, the moisture that has entered the finely pulverized product is released to the outside air from the vent port provided in the melt extruder. A high-quality recycled resin whose moisture content has been reduced to almost 0 wt% by releasing moisture is stably extruded from the extrusion port of the melt extruder, and is cut into pellets after cooling, Is done. Then, the obtained recycled resin alone or mixed with virgin resin is molded again into a container, a tray or the like.

  In the present invention, the melt extruder to be used may be a single extruder or a multi-stage extruder in which a first melt extruder and a second melt extruder are arranged in series. In the latter case, a multistage melt extruder in which a decompression chamber is formed at the connecting portion between the melt resin extrusion port of the first melt extruder and the melt resin inlet of the second melt extruder may be used. Good. When a multistage melt extruder having a decompression chamber at the connecting portion is used, volatile matter contained in the recycled resin can be further removed, and thus a higher quality recycled resin can be obtained.

  In the present invention, the resin type, expansion ratio, shape, and size of the foamed resin sheet-molded container recovered from the market are arbitrary and are not particularly limited. When the coarsely pulverized product is used, the amount of water permeating from the pulverized surface is small, and therefore, it is preferable to apply the present invention to recycling of a polystyrene foamed resin container having many closed cells. The expansion ratio depends on the expansion ratio of various types of foamed resin sheet molded containers collected from the market, but there are many containers in the range of about 5 to 22 times from the viewpoint of strength and heat insulation, and these are suitable for these containers. The present invention can be applied to.

  According to the present invention, the foamed resin sheet molded containers recovered from the market can be effectively recycled as recycled resin with less energy, in a short time, and without using a vacuum drying device or a hot air drying device. Become.

Process drawing explaining an example of the recycling system by this invention. The 1st figure explaining an example of the recycling apparatus by this invention. The 2nd figure following the 1st figure. The figure explaining an example of the melt extruder used by this invention.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the process diagram shown in FIG. 1 and the apparatus diagrams shown in FIGS.

  The resin container to be recycled in the present invention is a foamed resin sheet molded container collected from the market. In general, many types of resin containers collected from the market are mixed, and first, a molded container of a foamed resin sheet is selected from among them (S10). After sorting, if necessary, the sorted resin container is washed (S11). This process (S11) may be omitted. The resin container to be recycled is a foamed resin sheet molded container. The sorting operation may be performed manually, and the foamed resin sheet molded container is relatively light compared to the non-foamed resin molded container, so that a wind sorter or the like can be used.

Next, the selected resin container is coarsely pulverized so as to have an average size in the range of about 7 to 300 cm ² by using a conventionally known appropriate coarse pulverizer 1 (S12). . If necessary, it may be stored in the silo 2 as a buffer (S13). Next, the coarsely pulverized product is washed with water by the water washing machine 3 (S14). The water washing machine 3 is preferably a rotary blade or screw type, and water and a coarsely pulverized product are poured into the water washing machine 3 to wash away proteins and foreign matters (solid matter). Preferably, the water washer 3 is installed at an inclination of about horizontal to about 30 degrees, and water and the coarsely pulverized product are introduced from the inclined upstream end, and the washed coarsely pulverized product is taken out from the other end.

  Next, the coarsely pulverized product after washing is transferred while draining water on the conveyor 4 or the like (S15), and is put into the hot water washing machine 5 to perform hot water washing (S16). The hot water washer 5 is for washing an object with warm water of approximately 30 to 70 ° C. containing alkali or soap, and preferably removes oil and fat while stirring with a rotating blade or screw method. Also in the case of the hot water washer 5, it is preferably installed with an inclination of about horizontal to 30 degrees, and the cleaning water and the coarsely pulverized product are introduced from the inclined upstream end, and the washed coarsely pulverized product is taken out from the other end.

  Next, the coarsely pulverized product after the hot water washing is transferred by the washing movers 6 and 6 (S17, S18). The washing and moving machine 6 performs washing and transfer while hitting the coarsely pulverized product coming out of the hot water washing machine 5 with water, and may be one machine, or a plurality of machines may be arranged in series as shown. The installation angle is preferably inclined by 5 to 45 degrees toward the transfer direction in order to improve drainage.

  In the steps up to S18, the necessary cleaning process for the coarsely pulverized product is completed. Moisture adheres to the surface of the coarsely pulverized product drained in step S18, and moisture penetrates from the fracture surface to the inside by about 1 to 3 mm through the foamed bubbles appearing on the fracture surface.

  Next, the coarsely pulverized product coming out of the washing and moving machine 6 is put into the dehydrator 7 to perform a dehydration process (S19). The dehydrator 7 to be used may be a physical dehydrator such as a screw press method or a centrifugal separation method, and does not require the use of a dryer with a thermal treatment such as a heated hot air treatment. The dewatering process is performed by the dehydrator 7 until the water content of the coarsely pulverized product becomes approximately 18 wt% or less, preferably 10 wt% or less.

Next, the coarsely pulverized product having a water content of approximately 18 wt% or less is charged into the fine pulverizer 8, and is finely pulverized to an average size of approximately 0.2 to 6 cm ² to obtain a finely pulverized product (S20). If the finely pulverized product has this size, water can be sufficiently removed from the vent port of the melt extruder, and the volume reduction and melting of the finely pulverized product can be stably extruded. The finely pulverized material that has been finely pulverized by the fine pulverizer 8 is stocked in the silo 9 as required (S21).

  Finally, the finely pulverized product is charged into the melt extruder 10 (S22). The finely pulverized product charged is reduced in the process of passing through the melt extruder 10 and melted by being heated and pressurized. In the process, water of approximately 18 wt% or less, preferably 10 wt% or less, contained in the finely pulverized product is almost completely removed from the vent port provided in the melt extruder 10. Therefore, a high-quality recycled resin is stably extruded from the extrusion port of the melt extruder 10. There is no restriction | limiting in the form of a melt extruder, A twin with a push hopper, a single or a tandem type extruder etc. can be used suitably. The melt extruder 10 will be described in detail later.

  The recycled resin extruded from the melt extruder 10 is pelletized by, for example, a conventionally known pelletizer 11 (S23), and then appropriately stored in a bag or silo.

  As described above, in the recycling method and apparatus for the market-recovered foamed resin container according to the present invention, a thermal drying apparatus that requires a lot of energy is used to remove moisture adhering during cleaning from the pulverized product after cleaning. Even if it is not, water can be removed up to the required water content, and after making the coarsely pulverized product after moisture removal into a finely pulverized product, a good recycled resin can be obtained by putting it into a melt extruder . This makes it possible to regenerate the resin in a short time with less energy, at a lower cost, and with less expensive equipment than in the conventional recycling method and apparatus.

  In the present invention, the water supplied to the water washing machine 3 and the washing mobile machine 6 can be drained out of the system as they are after the treatment. However, in order to use the water efficiently, the water is circulated and recycled. It is desirable to use it. For this purpose, the water drained from the water washer 3, the washing mover 6 and the dehydrator 7 is directly returned to the water treatment facility 21 by the treated water return pump 20, where necessary water purification treatment is performed, and then water washing is performed again. It is recommended to supply to the machine 3 and the washing machine 6. Further, as shown in the process diagram of FIG. 1, the washing machine 3 uses more water. After being circulated, it may be returned to the water treatment facility 21 by the treated water return pump 20.

  In the present invention, the washing water used in the step of washing the coarsely pulverized product after washing with warm water of about 30 to 70 ° C. containing alkali or soap can also be drained out of the system as it is after the treatment. However, in order to efficiently use the wash water, it is desirable to construct and reuse the circulation system.

  An example of the circulation system is shown in the process diagram of FIG. Here, the circulation system includes a heat pump unit 31 as a heat source, a cushion tank 32 for securing a heat quantity necessary for heat exchange, a first unit 30 including a heat exchanger 33, and a washing mobile unit 6. A tank 41 for temporarily storing treated water, a coarse filter 42, a tank 43 for temporarily storing treated water from the coarse filter 42, a fine filter 44, and a treated water from the fine filter 44 are temporarily stored. The tank 45 and the second unit 40 including the heat exchanger 33 are configured.

  The 1st unit 30 is for raising the temperature of the washing | cleaning warm water supplied to the warm water washing machine 5 to about 30-70 degreeC, and the 40-80 degreeC heat medium (heat | fever) produced | generated by the heat pump unit 31 is used. Water) is sent to the heat exchanger 33, and heat is exchanged with the washing warm water containing alkali or soap passing therethrough, thereby raising the temperature of the washing warm water to approximately 30 to 70 ° C. The heat pump unit 31 is an example of a heat source, and in addition, boilers, heaters, self-generated power exhaust, cooling water exhaust heat, and the like can be reused.

  The second knit 40 is a circulation system of the washing hot water. The washing water containing alkali or soap in the alkaline water tank 46 is heated to about 30 to 70 ° C. by passing through the heat exchanger 33, and then poured or showered from the upper part of the inlet of the hot water washing machine 5. It is thrown. And it is discharged | emitted to the washing | cleaning movement machine 6 with the coarsely pulverized material from the exit upper part of the warm water washing machine 5. When passing through the cleaning mobile unit 6, the cleaning hot water and the coarsely pulverized product are separated, and the cleaning hot water is temporarily stored in the tank 41.

  Then, after the foreign substance is removed in the coarse filter 42, the washing hot water is again stored in the tank 43 and moves from there to the fine filter 44. The coarse filter 42 removes a visible level of foreign matter, and the fine filter 44 removes the foreign matter to a level that does not hinder the use of the heat exchanger 33. The coarse filter 42 and the fine filter 44 having such functions may be well known, and detailed description thereof is omitted. Washing hot water containing alkali or soap that has passed through the microfilter 44 is stored in the tank 45 and then moved again to the heat exchanger 33 described above. When the washing warm water circulates as described above, the insufficient washing water is replenished from the alkaline water tank 46 described above.

  Note that a thermometer 47 is attached to the tank 45 to measure the temperature of the washing hot water fed to the heat exchanger 33. The temperature information is sent to control means (not shown) and used for temperature control in the heat exchanger 33. The microfilter 44 and the tank 45 are also provided with treated water or water supply means 48 for backwashing the filter provided there.

  Next, the melt extruder 10 will be described. As described above, in the recycling method and apparatus for the market-recovered foamed resin container according to the present invention, the melt extruder 10 to be used appropriately uses a series or multiple melt extruder of the type conventionally known in this technical field. be able to. However, by using the novel melt extruder 10 shown in FIG. 4, a higher quality recycled resin can be obtained.

  The illustrated melt extruder 10 includes a first melt extruder 50 and a second melt extruder 60. The two melt extruders 10, 60 themselves may be conventionally known extruders. In this example, the first melt extruder 50 is supplied into the hopper 51 into which the finely pulverized material, which is the raw material of the recycled resin, is charged, the cylinder 52 to which the outlet side of the popper 51 is connected, and the cylinder 52. A screw 53 for transferring the raw material while reducing the volume and melting, and an extrusion port 54 through which the recycled resin reduced in volume and melted is extruded. The screw 53 is rotationally driven by an appropriate drive source M1. Although not shown, appropriate heating means such as a band heater for heating and melting the raw material is disposed on the outer periphery of the cylinder 52.

  The hopper 51 may be of any form, but in the illustrated example, it is a push-in hopper, and a supply screw 55 is attached to the hopper 51 so that the raw material can be press-fitted into the cylinder 52 by a certain amount.

  The screw 53 includes a first screw 53a on the upstream side in the raw material transfer direction and a second screw 53b on the downstream side connected to the first screw 53a. A connecting portion between the first screw 53a and the second screw 53b is a small-diameter portion 56, and a vent port 57 that functions to extract air or moisture is provided in a portion of the cylinder 52 that faces the connecting portion. ing. As described above, the moisture contained in the finely pulverized material that is the raw material of the recycled resin can escape from the vent port 57 together with the air, and the molten resin extruded from the extrusion port 54 contains almost no moisture. .

  The second melt extruder 60 also includes a cylinder 61, a screw 62 disposed in the cylinder 61 for transferring the regenerated molten resin, and a regenerated molten resin extrusion port 63. The screw 62 is rotationally driven by an appropriate drive source M2. Although not shown, appropriate heating means such as a band heater for controlling the temperature of the recycled molten resin is disposed on the outer periphery of the cylinder 61. The cylinder 61 has a recycled molten resin intake 64 on the upstream side, and the recycled molten resin extruded from the extrusion port 54 of the first melt extruder 50 passes through the connecting portion 100 described later and melts. Enter the resin inlet 64. The entered recycled molten resin is quantitatively sent to the extrusion port 63 by the rotation of the screw 62 for transferring the recycled molten resin, and is quantitatively discharged.

  The above-described connecting portion 100 will be described. The connecting part 100 includes a pipe line part 101 connected to the extrusion port 54 in the first melt extruder 50 and a decompression chamber 103 in which the downstream end 102 of the pipe line part 101 is opened. The downstream end of the decompression chamber 103 is connected to the resin intake 64 of the cylinder 61 described above. The entire connecting portion 100 has a sealed structure so that the recycled molten resin passing through the inside can pass without contacting with the outside air.

  The diameter of the pipe section 101 is the same as or substantially the same as the diameter of the extrusion port 54 and is not essential, but in this example, the pressure acting on the recycled molten resin passing through the pipe section 101 is adjusted in the middle. A pressure adjusting means 104 is provided. The pressure adjusting unit 104 is preferably a choke valve capable of variably controlling the diameter of the pipe line part 101 from the viewpoint of ease of configuration and ease of operation, but is not limited thereto, and the pipe line part is not limited thereto. A baffle plate such as a melt throughr may be disposed on the surface.

  The decompression chamber 103 described above is connected to a vacuum pump (not shown), and the interior of the chamber is maintained at a required reduced pressure by a control device (not shown). Further, although not essential, in the example shown in the figure, a flow dividing means 105 is attached to the downstream end of the pipe line portion 101 opened in the decompression chamber 103. The diversion means 105 diverts the regenerated molten resin flowing out from the pipe line portion 101 as a single flow into a plurality of flows, and is exposed to the depressurized state in the decompression chamber 103 by the diversion. The surface area of the molten resin is increased.

  In the above-described molten pressing machine 10, the raw material for the recycled resin, which is the finely pulverized product, is supplied from the hopper 51 into the cylinder 52. The supplied raw material is fed by the screw 53 toward the extrusion port 54 through the cylinder 52 while being heated by a heating device (not shown). A compressive force corresponding to the shape of the screw 53 acts on the raw material, and the resin raw material (finely pulverized product) is gradually reduced in volume and melted by the compression and shearing force. In addition, degassing from the raw material gradually proceeds. And the pressure which acts temporarily in the connection part of the 1st screw 53a and the 2nd screw 53b becomes low, and most of air, a water | moisture content, a volatile component, etc. in a raw material are deaerated from the vent port 57. FIG. .

  The degassed and dehydrated recycled molten resin flows into the pipe part 101 of the connecting part 100 from the extrusion port 54 of the cylinder 52 and is pushed out from the downstream end 102 into the decompression chamber 103. A diversion means 105 is provided at the extrusion port in the decompression chamber 103, and the regenerated molten resin pushed out (flows out) as a single flow from the pipe line portion 101 is diverted into a plurality. Thereby, the surface area of the regenerated molten resin increases in accordance with the number of diverted pipes.

  On the other hand, the inside of the decompression chamber 103 is decompressed to a required degree of vacuum by the action of a vacuum pump, and the recycled molten resin having a large surface area is exposed to a decompressed state. Thereby, the volatile components present on the surface and inside of the regenerated molten resin and the slight moisture when remaining are effectively removed from the regenerated resin. Then, the regenerated molten resin after the volatile components and moisture are almost completely removed flows into the cylinder 61 from the resin inlet 64 of the second melt extruder 60, and is supplied by the screw 62 for regenerated molten resin transfer. It is sent quantitatively to the extrusion port 63 and discharged from there. The recycled molten resin discharged quantitatively from the extrusion port 63 is one from which volatile components and moisture have been almost completely removed, and a high-quality recycled resin can be obtained.

  Note that the decompression chamber 103 has a space that can sufficiently evacuate volatile components and a small amount of remaining moisture, and has a size that prevents the flows of the regenerated molten resin that has been divided into a plurality from contacting each other. It is desirable. The residence time until the split recycled resin comes out of the splitting means 105 and contacts the screw 62 of the second melt extruder 60 is generally 1 second or longer, preferably 1.5 seconds or longer. This residence time can be adjusted by controlling the shape and size of the decompression chamber 103 and the amount of extrusion. When the residence time in the decompression chamber 103 is insufficient, a baffle device such as a wire mesh can be set, and if necessary, this can be set in multiple stages to adjust the residence time. The melt extruder shown in FIG. 4 is described in detail in Japanese Patent Application No. 2011-124371 related to the applicant's application.

  A melt extruder in which the decompression chamber 103 is removed from the melt extruder 40 shown in FIG. 4 or an extruder having only the first melt extruder 50 can also be used as the melt extruder according to the present invention.

Next, an actual example performed by the present inventors will be described. In the experiment, many of the temporarily used foamed resin sheet molding containers were collected from the market indiscriminately. The collected product is put into a pulverizer, and the size of the overnet attached under the pulverizer is changed, so that samples of coarsely pulverized products having an average coarse pulverization size (cm ² ) shown in Table 1 as 1 to 7 are shown. made. In addition, since the sample with an average size of 100 cm ² or more of the coarsely pulverized product could not be obtained with the used pulverizer, it was prepared with a press cutting device with a cutter blade.

About each sample, the process to S14-S22 in FIG. 1 was performed. In the process, the average washing time, the amount of pulverized powder, the average fine pulverization size, and the water content (after dehydration / fine pulverization) were measured. Further, as the melt extruder, a melt extruder in which the decompression chamber 103 is removed from the melt extruder 40 shown in FIG. 4 is dehydrated by the dehydrator 7 and the average size is 0.9 to 0.9 by the fine pulverizer 8. What was finely pulverized to 2.4 cm ² was stored in the silo 9, melted by the melt extruder 10, and evaluated when extruded from the nozzle of the extrusion port 63. The results are shown in Table 1.

The average coarsely pulverized product size and the average finely pulverized product size were measured as follows. That is, the pulverized product was scooped 5 times every 5 to 10 minutes while pulverizing the coarsely pulverized product into a cocoon with a side of 10 cm and the finely pulverized product with a heel of 5 cm on a side. However, grinding size collected in a plastic bag filled of 180 mm × 270 mm for those of 50 to 100 cm ^2, in excess of 100 cm ² were collected in a plastic bag filled of 300 mm × 450 mm, 5 to 10 minutes while a similarly comminuted Samples were scooped 5 times each. When the sample was not rectangular, the long direction was the long side and the perpendicular direction was the short side, and each length was measured to be the crossing area, and the average of the areas was calculated for each ridge. The same operation was repeated 5 times, and the weighted average was taken as the average value.

In Table 1,
The average washing time is the time for passing through the water washing machine 3, the conveyor 4, the hot water washing machine 5, the two washing moving machines 6 and 6, and the dehydrator 7.
-The amount of pulverized powder is the amount of powder generated during pulverization and washing. After the washing warm water containing alkali or soap discharged together with the coarsely pulverized product after washing with warm water is separated from the coarsely pulverized product, 60 A mesh wire mesh was installed, and the amount of powder filtered there was measured.
-The water content (after dehydration) was calculated from the difference in weight between 100 L after taking out the sample after passing through the dehydrator 7, and after being sufficiently dried in the dryer.

[Evaluation]
In Samples 1 and 2, the water content of the finely pulverized product after dehydration increased to 42 wt% and 27 wt%. Extrusion from the melt extruder was not stable due to the large amount of moisture. This is because the average pulverized size of the pulverized product when coarsely pulverized was too small as 4 cm ^2, and water was washed when the pulverized product per unit amount (for example, 100 L) was internally washed from the pulverized surface of each pulverized product. Intrusion increases the total amount of moisture, and sufficient dehydration cannot be performed only by the dehydration treatment by the dehydrator 7. Even if water is removed (dehydrated) from the vent port 57 of the melt extruder 10, moisture remains in the recycled molten resin. This is probably due to the fact that

  In Samples 1 and 2, since the average pulverized size of the pulverized product is small, the amount of finely pulverized powder in the next process also increases, and there is a tendency that the filtration load of the washing warm water increases accordingly.

In sample 7, the average particle size of the coarsely pulverized product was as large as 400 cm ^2, and it was difficult to transport air by piping between the processes, which caused a decrease in productivity. In addition, as a result of throwing into the melt extruder after fine grinding and observing the extrusion state, the extrusion was good.

  Samples 3 to 6 were excellent in air transportation by piping and high in productivity, and were able to be extruded with good stability and extrusion with a melt extruder.

From the above, the market-recovered foamed resin containers are roughly pulverized to an average size of about 7 to 300 cm ² and coarsely pulverized, and the average size of the coarsely pulverized product dehydrated to about 18 wt% or less is about 0.00. By finely pulverizing to ² to 6 cm ² to obtain a finely pulverized product, a high-quality recycled resin can be stabilized with less energy in a short time using a conventionally known melt extruder and without using a heat drying apparatus. It can be seen that it can be extruded.

1 ... Coarse grinder
2 ... Silo,
3 ... water washer,
4 ... conveyor,
5 ... Warm water washer,
6 ... Cleaning and moving machine,
7 ... Dehydrator
8 ... Fine grinding machine,
9 ... silos,
10: Melt extruder.

Claims (4)

A method for recycling foamed resin sheet molded containers collected from the market as recycled resin,
Roughly pulverizing the market recovered foamed resin container to an average size of approximately 7 to 300 cm ² to obtain a coarsely pulverized product;
Washing the coarsely pulverized product with water;
A step of washing the coarsely pulverized product after washing with water with warm water of approximately 30 to 70 ° C. containing alkali or soap;
Washing, transferring and draining while hitting the coarsely pulverized product after washing with warm water with water;
A step of reducing the water content to about 18 wt% or less by physical dehydration without heating and drying the drained coarsely pulverized product after the washing and transfer ;
A step of finely pulverizing the coarsely pulverized product dehydrated to approximately 18 wt% or less to an average size of approximately 0.2 to 6 cm ² ,
A step of reducing and melting the finely pulverized product using a melt extruder to obtain a recycled molten resin;
The recycling method of the market collection | recovery foamed resin container characterized by including at least.   The melt extruder includes a first melt extruder and a second melt extruder arranged in series, and a melt resin extrusion port of the first melt extruder and a melt resin inlet of the second melt extruder, The method for recycling a market-recovered foamed resin container according to claim 1, wherein a decompression chamber is formed in the connecting portion of the two and a melt extruder is used. An apparatus for recycling foamed resin sheet molded containers collected from the market as recycled resin,
A coarse pulverizer for coarsely pulverizing the market recovered foamed resin container to an average size of approximately 7 to 300 cm ² to obtain a coarsely pulverized product;
A water washing machine for washing the produced coarsely pulverized product with water;
A hot water washing machine for washing the coarsely pulverized product after washing with water with warm water of approximately 30 to 70 ° C. containing alkali or soap;
A washing and moving machine for washing, transferring and draining while hitting the coarsely pulverized product after washing with warm water with water;
A dehydrator capable of reducing the water content to about 18 wt% or less by physical dehydration without heating and drying the drained coarsely pulverized product after the washing transfer ;
A fine pulverizer for finely pulverizing the dehydrated coarsely pulverized product to an average size of approximately 0.2 to 6 cm ² ;
A melt extruder for reducing and melting the finely pulverized product to obtain a regenerated molten resin;
A recycling apparatus for a market-recovered foamed resin container, characterized by comprising at least:   The melt extruder includes a first melt extruder and a second melt extruder arranged in series, and a melt resin outlet of the first melt extruder and a melt resin inlet of the second melt extruder The recycling apparatus for a market-recovered foamed resin container according to claim 3, wherein a decompression chamber is formed at the connecting portion of the connecting portion and is a melt extruder.

Images