JP2001342288A - Method for recycling thermoplastic resin and apparatus used for the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide both a method for recycling a thermoplastic resin by which the thermoplastic resin is recycled without being deteriorated and an apparatus used therefor. SOLUTION: This method for recycling the thermoplastic resin comprises fuidizing a molded product made of the thermoplastic resin with a solvent substantially dissolving the thermoplastic resin, preparing a fluidized material of the molded product and then carrying out a step of separating the solvent and recovering a composite evaporated material for performing the addition of a substance incompatible with the solvent in the solvent-containing fluidized material and having a lower boiling point than that of solvent to the solvent, separation of the solvent from the solvent-containing fluidized material under conditions of a temperature not higher than the boiling point of the solvent and not lower than the boiling point of the low-boiling substance by evaporation of the solvent from the solvent-containing fluidized material and recovery of the composite evaporated material for recovering the separated solvent together with the above substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating a thermoplastic resin from a fluidized molded product obtained by dissolving a molded thermoplastic resin with a solvent, and an apparatus used for the method.

[0002]

2. Description of the Related Art In general, as a method for regenerating a molded article of thermoplastic resin such as styrene foam, a molded article is dissolved in a solvent, and then the solvent is removed from the solution by distillation at a temperature not lower than the boiling point of the solvent. Regeneration of thermoplastic resins has been performed. Conventionally, as a method for regenerating a thermoplastic resin, Japanese Patent Application Laid-Open No. 9-3239 discloses a method in which styrene-based resin waste is dissolved in a solvent and distilled at a temperature of 210 to 260 ° C. under a reduced pressure of 40 to 60 torr. Patent Document 1 discloses an invention in which a solvent is removed to regenerate a thermoplastic resin.

[0003]

However, in the above method, the resin solution must be heated to at least the evaporation temperature of the solvent under reduced pressure. For this reason, the resin is thermally decomposed, the molecular weight is reduced, the denaturation occurs, and the resin cannot be regenerated in a good state. Therefore, an object of the present invention is to solve the above problems, and at a low temperature not higher than the boiling point of the solvent to be used, to remove the solvent and to regenerate the thermoplastic resin without causing thermal decomposition. It is an object of the present invention to provide a method of reproducing an object and an apparatus used for the method.

[0004]

An object of the present invention is to provide a method for regenerating a thermoplastic resin, which comprises molding a thermoplastic resin molded article by using a solvent which substantially dissolves the thermoplastic resin. After preparing a fluidized molded product obtained by fluidizing a molded product, adding a substance having an incompatibility with the solvent and a low boiling point to the solvent-containing fluidized substance and a boiling point of the boiling point of the solvent or lower and the boiling point of the low boiling substance A heat separation / combined evaporate recovery step for performing separation by evaporation of the solvent from the solvent-containing fluidized material under the above temperature conditions and recovery of a combined evaporate for recovering the separated solvent together with the substance. This is a method for regenerating a plastic resin. The method for regenerating the thermoplastic resin preferably includes a step of liquefying the composite evaporant and a step of recovering the solvent from the liquefied substance.

In order to achieve the above object, a fluidized thermoplastic resin molded article obtained by using a solvent dissolving a thermoplastic resin is added to a fluidized molded article which is incompatible with the solvent and has a low boiling point. A substance is added, and the solvent is evaporated together with the low-boiling substance under a temperature condition equal to or lower than the boiling point of the solvent and equal to or higher than the boiling point of the low-boiling substance to be separated into a thermoplastic resin and a composite evaporate. This is a method for regenerating a thermoplastic resin in which a separated composite evaporate is recovered and liquefied, and then a solvent is recovered from the liquefied material. The low-boiling substance incompatible with the solvent is, for example, water. further,
The heating temperature of the solvent-containing fluidized material in the solvent separation / composite vapor recovery is preferably equal to or lower than the melting temperature of the regenerated thermoplastic resin. Further, the solvent separation / combined evaporate recovery is performed in a separation device, and the addition of a substance having a low boiling point and being incompatible with the solvent to the separation device is continuously performed little by little. It is preferable to be performed.
Further, the method of regenerating the thermoplastic resin, the solvent separation,
After the completion of the solvent separation from the fluidized material in the composite evaporant recovery step, a flake forming step of making the resin composition into a flake by simultaneously adding a cooling liquid to the resin composition and subdividing the resin composition. It is preferred to do so. Further, it is preferable that the method further comprises a filler addition step of adding a filler before the solvent separation / composite evaporation product recovery, during the solvent separation / composite evaporation product recovery, or after the solvent separation / composite evaporation product recovery. Further, the filler,
For example, it is at least one selected from wood powder, ceramic powder, resin, lubricant, pigment, stabilizer, paper powder, and fiber. And the thermoplastic resin molded product is, for example,
It is a molded product made of foamed thermoplastic resin.

[0006] Further, what achieves the above object is a regenerating apparatus used in a method for regenerating a molded article made of a thermoplastic resin, wherein the regenerating apparatus is provided with a separating device, and the separating device is provided. Is composed of a separation device and an evaporant recovery device.The separation device has a function of injecting a fluidized material obtained by fluidizing the object of regeneration processing using a solvent that dissolves the object of regeneration processing, and is added to the object of regeneration processing. A low-boiling substance adding function for adding a low-boiling substance for the solvent, a subdivision function for subdividing the object to be regenerated provided in the separation apparatus, A heating function for heating, wherein the evaporant recovery device is for recovering a mixed evaporate of a solvent and a substance for lowering the boiling point, and is used as a separation device for a thermoplastic resin molded product regenerating device. It is. Then, the mixed evaporant recovery function is a liquefaction function for liquefying the mixed evaporate, a tank for storing the liquefied material, and a solvent collected from the solvent and the low-boiling-point substance composite evaporate separated in the tank. Is preferably provided.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for regenerating a thermoplastic resin and an apparatus for regenerating a thermoplastic resin according to the present invention will be described with reference to the embodiments shown in the drawings. FIG. 1 is an explanatory view for explaining a thermoplastic resin regenerating apparatus according to an embodiment of the present invention, and FIG. 2 is an embodiment used for the thermoplastic resin regenerating apparatus shown in FIG.

[0008] The method for regenerating a thermoplastic resin according to the present invention comprises the steps of preparing a fluidized molded product obtained by fluidizing a molded product of a thermoplastic resin using a solvent that substantially dissolves the thermoplastic resin. The addition of a substance having a low boiling point to the solvent-containing fluidized substance and being incompatible with the solvent and separating the solvent from the solvent-containing fluidized substance under a temperature condition not higher than the boiling point of the solvent and not lower than the boiling point of the low-boiling substance; It is provided with a solvent separation / composite recovery step of recovering a composite in which the separated solvent is recovered together with a low-boiling substance. In addition, the method for regenerating a thermoplastic resin of the present invention uses a solvent that dissolves the thermoplastic resin, and a fluidized molded product obtained by fluidizing a thermoplastic resin molded product is incompatible with the solvent and has a low boiling point. A substance is added, and the solvent is evaporated together with the low-boiling substance by utilizing a low-boiling phenomenon under a temperature condition equal to or lower than the boiling point of the solvent and higher than the boiling point of the low-boiling substance. After separating into a composite evaporate and further collecting and liquefying the separated composite evaporate, a solvent is recovered from the liquefaction.

The thermoplastic resin to be subjected to the regeneration method of the present invention may be any thermoplastic resin in which a soluble solvent is present. Examples thereof include styrene-based resins such as polystyrene and acrylic styrene copolymer. Resins, olefin resins such as polyethylene and polypropylene, and vinyl chloride resins. In addition, any molding may be used as a recycled material, but a foam molding is particularly effective. Therefore, the objects to be regenerated by the regenerating method of the present invention are effective for styrofoam moldings, foamed polyethylene moldings, foamed polypropylene moldings, and the like. Specifically, trays, packing materials (shock absorbing materials), fish markets, Containers and the like used in fruit and vegetable markets are considered to be the main targets for reproduction. Also, sandals, shoe soles, packings, cushioning materials, foam sheets, furniture members, and the like made of vinyl chloride or the like are applicable. Hereinafter, as a method for regenerating a thermoplastic resin of the present invention, an example of a method for regenerating polystyrene using a molded styrene foam will be described.

In the method for regenerating a thermoplastic resin according to the present invention, first, a fluidized molded product is prepared by fluidizing a molded product of a thermoplastic resin using a solvent that substantially dissolves the thermoplastic resin. I do. The step of preparing a fluidized molded product is performed before the solvent separation / combined evaporate recovery performed later.
The location is not particularly limited. When processing a bulky object to be reproduced, such as a styrofoam molded product, it is preferable to perform the processing at the site where the object to be reproduced is generated or where the object to be reproduced is collected in consideration of distribution costs. Then, it is preferable to transport the reduced volume of the molded product as a fluidized product to a place where the solvent separation / combined evaporation product is collected. In addition,
The present invention is not limited to this, and may be performed at the same place. Before preparing the fluidized molded product, the molded product may be washed. The preparation of the fluidized molded product can be performed by immersing a thermoplastic resin molded product (reproduction target, specifically, a polystyrene foam molded product) in a solvent that substantially dissolves the resin. At this time, if necessary, heating of the solvent, stirring of the solvent after immersion, and the like may be performed.

As a solvent that substantially dissolves the molded article of the thermoplastic resin, a solvent that is hardly volatilized at room temperature is used. Further, as described later, in the present invention, water can be used as an additive for lowering the boiling point of the solvent, and therefore, the solvent is preferably incompatible with water. Further, the solvent differs depending on the target thermoplastic resin. When the resin to be regenerated is a styrene resin, an olefin resin, or a vinyl chloride resin, xylene, ethylbenzene, mixed C9 aromatics, isopropylbenzene, diethylbenzene, sec-butylbenzene, triethylbenzene, polyethylbenzene, high boiling point Hydrocarbons such as aromatics, butyl chlorides such as butyl chloride, ethylene dichloride, propylene dichloride, dicyclopentane, 1,1,2-trichloroethane, 1,2,3-trichloropropane, 1,1,2 , 2
-Chlorinated hydrocarbons such as tetrachloroethane, monochlorobenzene, dichlorobenzene, trichlorobenzene, and monochlorotoluene; ketones such as methylcyclohexanone and methyl isobutyl ketone; terpene solvents such as d-limonene, pinene, and dipentene; A mixture of two or more kinds can be used.

The term “substantially soluble” as used herein means that
It is not limited to the case where the molded product is completely dissolved, but refers to the fact that the solid that is the molded product and the liquid that is the solvent are almost uniformly mixed.The molded product is only partially dissolved and the molded product and the solvent are almost uniform. To a slurry. However, it does not include a sol state in which the solvent enters the inside of the molded product but the molded product and the solvent are not uniformly mixed. As the solvent, those capable of completely dissolving the resin component of the object to be regenerated are suitable.

Next, a substance having incompatibility with the solvent and having a low boiling point is added to the solvent-containing fluidized material, and the solvent-containing fluidized material is removed from the fluid containing the solvent by utilizing the phenomenon of lowering the boiling point under the temperature condition not higher than the boiling point of the solvent. The solvent separation / combined evaporant recovery step for separating the solvent will be described. The method for regenerating a resin from a fluidized material including the solvent separation / composite evaporation product recovery step can be performed, for example, using a regenerating apparatus as shown in FIG. Solvent separation
The case of using the apparatus shown in FIG. 1 for the composite evaporant recovery will be described as an example. As shown in FIG. 1, the thermoplastic resin regenerating apparatus 1 includes a first stirring tank 3, a second stirring tank 4, a third stirring tank 5, a separation device 2, and an evaporant collection tank 6. A condenser 7 for liquefying the vaporized mixed gas, a solvent recovery tank 8, an additive recovery tank 9 for lowering the boiling point, and a recycled thermoplastic resin recovery mechanism 10.

The thermoplastic resin regenerating apparatus 1 of the present invention comprises a first
2 stirring tanks 3 (capacity 1500 L), second stirring tank 4
(Volume 2000L) 1 tank, 3rd stirring vessel 5 (volume 100
0L) Two tanks are provided. As shown in FIG. 1, the container 11 containing the fluidized material is heated by steam or the like as necessary to maintain the viscosity of the fluidized material at a required value. At this time, the viscosity is preferably about 50 to 100 Pa · s. In addition, the above-described solvent may be added to lower the viscosity of the fluidized product. The fluidized slurry in the container 11a is sent to the first stirring tank 3 by the pump 12 and is stirred. The stirring is performed while the fluidized material is heated to 80 to 100 ° C. by the heating function 33 provided around the stirring tank 3. The stirring is performed by a filtration device 14 described later.
The viscosity is 10 so that it can easily pass through the filter of
The process is performed until the pressure becomes about 50 Pa · s. First stirring tank 3
Of the fluidized material is continuously performed from being fed to being discharged.

Next, the fluidized material stirred in the first stirring tank is sent to the filtration device 14 by the pump 13 and passes through the filter of the filtration device 14 to be contained in the solvent-containing fluidized material. Solids, such as fish scales, bones,
A piece of paper or the like is removed. 0.01m as a filter
What can capture the solid matter of about m or more is used. The fluidized material filtered by the filtration device is supplied to the pump 13
Is sent to the second stirring tank 4 to be stirred. Stirring is performed at 80 to 1 by a heating function 34 provided around the stirring tank 4.
The heating is performed at 00 ° C. until the viscosity becomes 10 to 50 Pa · s. The fluidized material stirred in the second stirring tank is
While adjusting the flow rate with the valve 15, it is sent to the third stirring tank 5 by the pump 16 and stirred. The stirring is performed while heating to 80 to 100 ° C. by the heating function 35 provided around the stirring tank 5 until the viscosity becomes 10 to 50 Pa · s. In the regenerating apparatus 1 of the embodiment, the solvent-containing fluidized material is fed in the order of the first stirring tank 3, the second stirring tank 4, and the third stirring tank 5, but the present invention is not limited to this.
For example, it may be directly sent from the first stirring tank 3 to the third stirring tank 5 via the filtration device 14, or may be sent directly from the first stirring tank 3 to the separation device 2 via the filtration device 14. It may be something.

Next, a solvent-incompatible and low-boiling substance is added to the solvent-containing fluidized substance and the solvent-containing fluidized substance is subjected to a temperature lower than the boiling point of the solvent and higher than the boiling point of the low-boiling substance. The solvent separation / composite recovery step of separating the solvent and recovering the separated solvent together with a low-boiling substance is performed. This solvent separation / combined evaporant recovery step is performed by a separation device including the separation device 2 and the evaporate recovery device. The separation device 2 has a function of injecting a fluidized material obtained by fluidizing the regenerating target using a solvent that dissolves the regenerating target, and a regenerating additive added to the regenerating target (for example, the aforementioned solvent). ), A function for adding a substance for lowering boiling point for adding a substance for lowering boiling point, a subdivision function (for example, a cutter) for subdividing an object to be regenerated, which is provided in the separation apparatus, and a separation apparatus. A heating function for heating the inside. The evaporant recovery device includes a condenser 7 for liquefying the evaporative gas mixture and an evaporant recovery tank 6.

Specifically, as shown in FIGS. 1 and 2, the separation device 2 has an addition function 23 for adding components in the distillation target and a low-boiling additive for lowering the boiling point. Subdivision function 22 that subdivides the object to be regenerated (solvent-containing fluidized material)
An evaporating gas outlet 25 provided at an upper portion, a fluidized material inlet 24, and a thermoplastic resin sampling port provided at a lower portion for removing a solvent-free thermoplastic resin (hereinafter referred to as a regenerated thermoplastic resin). 26. Further, when depressurizing the inside of the separation device, a depressurizing device is connected. In this embodiment, any additive having a lower boiling point than the solvent may be used as the additive for lowering the boiling point, as long as the additive has a specific gravity different from that of the solvent (preferably, the specific gravity is large) and is not compatible with the solvent.
Specifically, it is preferably water, and as an addition form, it is water vapor. In addition, as the additive for lowering the boiling point, alcohols such as ethyl alcohol and butyl alcohol can be used, but those which are difficult to ignite or ignite are preferable. Further, as the additive for lowering the boiling point, those having a boiling point lower than the melting temperature of the resin to be regenerated and the boiling point of the solvent are used. In this sense, water is also suitable as an additive for lowering the boiling point.

First, the fluidized material stirred in the third stirring tank 5 is injected into the separation device 2 while adjusting the flow rate with the valve 17 until the volume of the separation device 2 becomes 40 to 70% by volume. Then, water in a water vapor state is added to the inside of the separation device at normal pressure by an addition function (injection) 23 under a normal pressure.
Add while heating to 0-140 ° C. As a result, in the separation device, the solvent in the fluidized material evaporates together with water irrespective of the temperature below the boiling point due to the phenomenon of lowering the boiling point. The solvent separation is performed at a temperature equal to or lower than the boiling point of the solvent. The boiling point of the solvent in the solvent-containing fluidized material is reduced due to the partial pressure of water vapor (low boiling point phenomenon), and the solvent is sufficiently evaporated even at a low temperature. By utilizing the phenomenon of lowering the boiling point, the solvent can be separated (removed) at a low temperature (that is, a temperature sufficiently lower than the melting point of the thermoplastic resin and the boiling point of the solvent), and the thermal decomposition of the thermoplastic resin can be prevented. be able to.

It is preferable that the additive for lowering the boiling point (specifically, water) added in the solvent separation and the recovery of the combined evaporant is added in a sufficient amount with respect to the amount of the solvent in the fluid containing the solvent. Specifically, the amount of the solvent in the fluid containing the solvent is 10
It is preferable to add about 100 to 140 parts by weight to 0 parts by weight. In addition, in the solvent separation / combined evaporant recovery step, addition of the solvent-containing fluidized material into the separation device is performed as follows.
It is preferable to add the entirety of the fluid containing the solvent to be treated. In addition, you may perform by adding continuously little by little. It is preferred that the solvent-containing fluidized material is continuously added in a small amount and the low-boiling additive is simultaneously added. In addition, even when the solvent-containing fluidized material to be treated is added in its entirety, the addition of the low-boiling point additive is preferably performed continuously in a small amount. In addition, the solvent separation / combined evaporant recovery step may be performed under reduced pressure in the separation apparatus. By doing so, the lowering of the boiling point is promoted. In this case, the degree of reduced pressure in the separation device is preferably about 50 to 200 Torr.

Further, it is preferable that the solvent separation / combined evaporation product recovery step is performed while the solvent-containing fluidized substance added (filled) into the separation device is finely divided. Specifically, the solvent separation / composite evaporation product recovery is performed while chopping the solvent-containing fluidized material by a rotatable cutter (segmentation function 22) provided near the lower portion of the separation device 2 as shown in FIG. As a result, the specific surface area of the solvent-containing fluidized material increases, so that the solvent can be sufficiently and quickly removed from the solvent-containing fluidized material. The rotation speed of the cutter is 300-700rpm
m, preferably 325 to 650 rpm, and the rotation time of the cutter may be about 30 to 60 minutes. Due to the continuous fragmentation of the solvent-containing resin fluidized material by this cutter, the continuously fragmented fluidized material, while containing the solvent, is again integrated with the other fragmented materials while colliding with the separator wall. . By repeating this, the solvent separation from the fluidized material proceeds, and the viscosity of the fluidized material increases as the amount of solvent removed from the fluidized material increases. And it is preferable to perform the process of making the obtained regenerated thermoplastic resin into a flake shape. By performing such a step of forming the recycled thermoplastic resin flakes, the recycled thermoplastic resin can be easily taken out of the separation device, and can be used in the same manner as pellets. It will also be easier to use.

The solvent separation from the fluidized resin-containing material proceeds, and the viscosity of the fluidized material increases as the amount of solvent removed from the fluidized material increases. As a result, the load on the cutter increases, and the cutter current also increases (in the case of using a constant voltage source, the cutter voltage increases in the case of using a constant current source). When the load of the cutter reaches a predetermined value, specifically, the end of the solvent separation can be determined when the cutter current becomes equal to or more than the predetermined value (or when the cutter voltage becomes equal to or more than the predetermined value). Also, the end of solvent separation,
The determination can also be made based on a rise in temperature in the separation device due to frictional heat generated when the highly viscous fluidized material is subdivided by a cutter. The separation device used is provided with a temperature sensor (not shown) for measuring the temperature in the tank (for example, the temperature of the inner wall surface of the tank), and the temperature in the tank is constantly detected. As the amount of solvent removed from the fluidized material increases, the viscosity of the fluidized material increases, and when it exceeds a predetermined viscosity, frictional heat is generated. Then, when the temperature in the separation device reaches a predetermined value (specifically, when the temperature sensor detects the predetermined value), it is possible to determine the end of the solvent separation. It is preferable that the determination of the termination of the separation of the solvent from the fluidized material be made when both the above-described reaching of the predetermined value of the load of the cutter and the reaching of the predetermined value of the temperature in the tank are detected.

Then, as described above, after it is determined that the separation of the solvent from the fluid has been completed, cold water is supplied into the tank. The supply of cold water can be performed by the addition function (injection) 23 of water in a water vapor state. In particular, it is preferable to supply the mist. With the added cold water, the fluidized material is cooled and the surface is solidified.
It is subdivided by a cutter. By sequentially repeating this, a flake-like solidified material is obtained in a short time. At the time of supplying cold water, since the cold water is also supplied to the inside of the tank jacket, the temperature of the inner wall surface of the tank is also reduced, and even if the flake-like solidified material collides with the tank wall surface, it is not integrated again.
And, as the transition of fluidized material to flakes progresses,
The load on the cutter decreases, and the cutter current also decreases (in the case of using a constant voltage source, the cutter voltage decreases in the case of using a constant current source). When the load of the cutter reaches the second predetermined value, specifically, when the cutter current is equal to or less than the second predetermined value (or when the cutter voltage is equal to or less than the predetermined value), the flakes are formed. Can be determined.

Even if cold water is supplied as described above, the fluidized material is heated by the retained heat of the fluidized material, turned into steam, and removed.
The amount remaining in the recycled resin is extremely small. Also in this flake forming step, it is preferable to reduce the pressure inside the separation device. Then, the thermoplastic resin from which the solvent has been substantially removed (the thermoplastic resin in the form of flakes in this embodiment) is taken out from the separation device and used as a recycled material. Specifically, the regenerated thermoplastic resin taken out from the thermoplastic resin sampling port 26 is cooled by blowing, and then transported to the regenerated thermoplastic resin packaging device 10 via the empty transport line 21 and weighed, bagged, and the like. The recycled thermoplastic resin is used again as a thermoplastic resin molding material.

Further, the method for regenerating a thermoplastic resin comprises a solvent recovery step for separating a solvent from a solvent recovered by solvent separation and recovery of a composite evaporant and a composite evaporate having a low boiling point and being incompatible with the solvent. Is preferably performed. That is,
Since the solvent evaporated in the separation device is in a complex (mixed) state with the substance having a low boiling point, it is preferable to separate the solvent and water from this and reuse each. As shown in FIG. 1, the composite evaporate (solvent and water evaporate) recovered in the solvent separation / composite evaporate recovery step is:
It is liquefied by the condenser 7 communicating with the evaporative gas discharge port 25, stored in the composite liquid recovery tank 6, and left still.
In the tank 6, since the solvent and the additive are not compatible with each other, an upper layer is formed by a substance having a lower specific gravity, and a lower layer is formed by a substance having a higher specific gravity. In this embodiment, since the specific gravity of the solvent is smaller than the specific gravity of water, a solvent phase 61 is formed on the upper side and an aqueous phase 62 is formed on the lower side. The separated solvent is sent to a solvent recovery device by a pump 19 through a discharge port formed near the center of the recovery tank 6 as shown in FIG. Used for playback.
The separated water is collected by a pump 20 from a discharge port provided at a lower portion of the tank 6 into an additive collection tank 9 and is used again as a low boiling additive.

Further, a filler addition step for adding a filler may be provided before the solvent separation / composite recovery, during the solvent separation / composite recovery step, or after the solvent separation / composite recovery step. In the case where the filler addition step is performed before the solvent separation and the recovery of the composite evaporant, the addition is preferably performed after the solvent-containing fluidized material is filtered to remove impurities. In particular, it is preferable to add the filler during the solvent separation / composite recovery step, and the filler can be reliably dispersed in the resin by the stirring function of the cutter of the separation device without performing a special stirring operation. As filler, wood powder, ceramic powder, paper powder, resin, lubricant, pigment, stabilizer,
It is preferably at least one selected from a modifier and a fiber. Thereby, the properties of the resin can be improved. Fibers include glass fiber, metal fiber,
Non-resin fibers such as carbon fibers are used.

In the thermoplastic resin recycling apparatus 1 of the embodiment, the second stirring tank 4 or the third stirring tank 5 shown in FIG.
It is preferable to add a filler. In the case where the filler addition step is performed during the solvent separation and the recovery of the composite evaporant, the separation device 2 is used before the solvent-containing fluidized material is solidified by lowering the boiling point.
It is preferable to add and mix them. In addition, when the filler is added after the solvent separation and the recovery of the composite evaporant, it is preferable to add and mix the regenerated thermoplastic resin in a fluidized state by heating it to a moldable temperature. If the filler is wood flour,
It is considered that a filling rate of 30% by weight or more is sufficient.

[0027]

EXAMPLES Specific examples of the method for regenerating a thermoplastic resin of the present invention will be described below. (Example 1) About 60 kg of a food tray (made of expanded polystyrene) collected in a supermarket was prepared. A container having a capacity of 300 L and 200 L of a solvent (limonene) was prepared. While properly breaking the food tray by hand, put it into the solvent-filled container sequentially,
A 6 kg food tray was charged and dissolved to prepare a fluidized molded product.

Then, the fluidized material-filled container prepared as described above was transported to a regenerating apparatus installation place as shown in FIGS. 1 and 2, and regenerated. The solvent-containing fluidized material heated to about 40 ° C. by steaming the vessel was passed through the first stirring tank, and then filtered by a filtration device for 0.01 m.
m or more of the solid matter was removed, and after passing through the second and third stirring tanks, the mixture was injected into the separator. The temperature of the fluidized material at the time of injecting the fluidized material containing the solvent into the separation device is 1
The temperature was 00 ° C, and 200 L was charged. Then, the temperature in the separator was set to 120 ° C., the degree of pressure reduction was set to 150 Torr, and steam was injected into the separator. The steam injection conditions were 120 ° C., 2 × 10 ⁵ Pa, and the injection rate per hour was 200 kg / h. In addition, the cutter is continuously operated from the time when the solvent-containing fluidized material is introduced into the separation apparatus to the time when the separation is completed.
Rotated at 25 rpm. The combined evaporate evaporating from the separator was liquefied by a condenser and then collected in a tank.

When the current meter peak of the cutter rotating power (driven by the constant voltage source) reached 150 A, the solvent separation was terminated, the heating of the separator was stopped, and the steam injection was stopped. The steam injection time was about 30 minutes. Then, cold water was added to the separator from the steam injection nozzle by spraying, and the rotation of the cutter was maintained. The rotation speed was 325 rpm. The amount of cold water added per hour was 2000 g / min. Then, when the current meter of the cutter rotation power (driven by the constant voltage source) becomes 50 A, the resin composition flake formation is completed,
The addition of cold water and the rotation of the cutter were stopped. The cold water injection time was about 20 seconds. And about 55 kg of flake-like recycled polystyrene was obtained in this way. In addition,
The solvent content in the recycled polystyrene is 2% by weight,
The water content was 4% by weight. Also, the recycled polystyrene had not undergone thermal decomposition. The combined evaporant was separated into limonene in the upper layer and water in the lower layer in the tank, and each was separated and recovered from the tank.

(Example 2) Wood flour (average particle size: 3 mm) 15
kg in the same manner as in Example 1 except that wood flour was added into the separator at almost the same time as the solvent-containing fluidized material was injected into the separator, and the total amount of both was added in about 2 minutes. Approximately 66 kg of flaked recycled polystyrene containing wood flour
I got Incidentally, the solvent content in the recycled polystyrene,
It was 1.5% by weight and the water content was 4% by weight. Also, the recycled polystyrene had not undergone thermal decomposition.

[0031]

The method for regenerating a thermoplastic resin according to the present invention is a method for regenerating a thermoplastic resin, wherein a molded article made of a thermoplastic resin is molded using a solvent which substantially dissolves the thermoplastic resin. After preparing a fluidized product obtained by fluidizing the product, adding a substance having incompatibility and a low boiling point with respect to the solvent to the solvent-containing fluidized substance, and a boiling point of the solvent or less and a boiling point of the low boiling substance or more. A solvent separation / combined evaporant recovery step for separating the solvent from the fluidized material containing the solvent by evaporation under the above temperature conditions and recovering a combined evaporate for recovering the separated solvent together with the substance. Therefore, by lowering the boiling point of the solvent at a low temperature below the boiling point, the thermoplastic resin can be regenerated without deteriorating the thermoplastic resin. Furthermore, since a low-boiling substance is used that is incompatible with the solvent, it is easy to recover the solvent from the recovered composite evaporate, and the solvent can be reused. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a thermoplastic resin reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a separation device according to an embodiment used in the thermoplastic resin regeneration device shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Thermoplastic resin recycling device 2 Separation device 3 First stirring tank 4 Second stirring tank 5 Third stirring tank 6 Mixed solvent recovery tank 7 Condenser 8 Immersion solvent recovery tank 9 Additive solvent recovery tank 10 Recycled thermoplastic resin packaging Equipment 22 Subdivision function 23 Addition function

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D076 AA07 AA12 AA14 BA08 BC01 CB05 CD03 CD22 DA14 DA25 EA01X EA02Y EA08X EA11X EA12X EA16Y FA02 FA11 HA03 4F301 AA13 AA15 AA17 CA09 CA14 CA33 CA42 CA53 CA64 CA65

Claims (12)

[Claims] 1. A method for regenerating a thermoplastic resin, comprising preparing a fluidized molded product obtained by fluidizing a molded product made of a thermoplastic resin using a solvent that substantially dissolves the thermoplastic resin. After the addition of a low-boiling substance incompatible with the solvent to the solvent-containing fluidized substance and the solvent-containing fluidized substance under the temperature condition of the boiling point of the solvent or lower and the boiling point of the low-boiling substance or higher. A method for recovering a thermoplastic resin, comprising the steps of: separating by evaporation of the solvent and recovering a composite evaporant for recovering the separated solvent together with the substance. 2. The method for regenerating a thermoplastic resin according to claim 1, wherein the method for regenerating the thermoplastic resin includes a step of liquefying the composite evaporant and a step of recovering the solvent from the liquefied substance. 3. Using a solvent that dissolves a thermoplastic resin,
To a fluidized molded product obtained by fluidizing a thermoplastic resin molded product, a substance having an incompatibility with the solvent and a low boiling point is added,
The solvent is evaporated together with the low-boiling substance under a temperature condition equal to or lower than the boiling point of the solvent and equal to or higher than the boiling point of the low-boiling substance to be separated into a thermoplastic resin and a composite evaporate. A method for regenerating a thermoplastic resin, comprising recovering and liquefying, and then recovering a solvent from the liquefied product. 4. The method for regenerating a thermoplastic resin according to claim 1, wherein said substance having a low boiling point and being incompatible with said solvent is water. 5. The method for regenerating a thermoplastic resin according to claim 1, wherein a heating temperature of the solvent-containing fluidized material in the solvent separation / combined evaporate recovery is equal to or lower than a melting temperature of the regenerated thermoplastic resin. . 6. The method according to claim 1, wherein the separation of the solvent and the recovery of the combined evaporant are performed in a separation apparatus, and a small amount of a substance having a low boiling point and being incompatible with the solvent is added to the separation apparatus in a small amount. The method for regenerating a thermoplastic resin according to any one of claims 1 to 5, wherein the method is performed continuously. 7. The method for regenerating a thermoplastic resin includes the steps of: adding a cooling liquid to the resin composition and subdividing the resin composition after the completion of the solvent separation from the fluidized material in the solvent separation / combined evaporate recovery step. The method for regenerating a thermoplastic resin according to any one of claims 1 to 6, wherein a flake forming step is performed in which the resin composition is formed into flakes by simultaneously performing the forming. 8. A filler addition step for adding a filler before the solvent separation / combined evaporation collection, during the solvent separation / combined evaporation collection, or after the solvent separation / combination evaporation collection. 8. The method for regenerating a thermoplastic resin according to any one of the above items. 9. The filler may be wood powder, ceramic powder,
The method for regenerating a thermoplastic resin according to claim 8, wherein the method is at least one selected from a resin, a lubricant, a pigment, a stabilizer, a paper powder, and a fiber. 10. The method for regenerating a thermoplastic resin according to claim 1, wherein the thermoplastic resin molded product is a foamed thermoplastic resin molded product. 11. A regenerating apparatus used in a method for regenerating a molded article made of thermoplastic resin, the regenerating apparatus includes a separating device, and the separating device includes a separating device and an evaporant recovery. The separation device has a function of injecting a fluidized material obtained by fluidizing the reprocessing target using a solvent that dissolves the regenerating target, and a low boiling point for the solvent added to the regenerating target. Function for adding a chemical substance for reducing the boiling point, a subdivision function for subdividing the object of the regeneration treatment provided in the separation device, and heating for heating the interior of the separation device The apparatus for separating a thermoplastic resin molded product according to claim 1, wherein the apparatus has a function, and the evaporant recovery apparatus is for recovering a mixed evaporate of a solvent and a substance for lowering the boiling point. 12. The mixed evaporant recovery function includes: a liquefaction function for liquefying the mixed evaporate; a tank for storing the liquefied material;
The apparatus for separating a thermoplastic resin molded product according to claim 11, further comprising a collecting function for collecting a solvent from the solvent separated from the solvent and the substance having a low boiling point separated in the tank.