JPH07179651A - Process for treating thermoplastic resin waste - Google Patents

Abstract

PURPOSE:To reclaim a product of high value added especially e.g. difficultly combustible PVC in a process for treating thermoplastic resin wastes by dissolving the resin in a solvent, adding a precipitant to the solution and recovering the precipitated resin in the form of a solid powder. CONSTITUTION:This process comprises the steps of: (A) dissolving thermoplastic resin wastes in a solvent, (B) removing solid matter from the solution of A, (C) mixing the solution of B with a precipitant to precipitate the resin, (D) separating the deposited resin of C, (E) removing by aspiration the adherent matter from the precipitated resin of D and drying and recovering the resin, and (F) separating the solvent, the precipitant and the plasticizer from the solution from which the resin is removed and recirculating the separated substances to the upstream steps. The solvent of A is ethylene dichloride(EDC) or the like for PVC and is xylene or the like for polystyrene. If required, a plasticizer compatible with the precipirant is actively added. Although the precipitant of C is selected according to the solubility parameter, methanol or the like is usually used. Highly pure PVC can be recovered in high yields.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment process for separating and recovering a resin and a plasticizer from a waste of a thermoplastic resin for recycling.

[0002]

2. Description of the Related Art Various plastics such as polyethylene, polypropylene and polyvinyl chloride are widely used in various daily necessities and are essential materials for our modern life. On the other hand, the use of these various plastics makes daily life richer and more convenient, but on the other hand, the waste treatment of a large amount of plastics is a problem, and due to its non-oxidizing property and non-microbial degradability, it has become a problem in recent years. Is becoming a factor that complicates and increases Polyethylene, polypropylene, etc. can be burned, but polyvinyl chloride generates corrosive chlorine gas due to irritating odor when burning, and polystyrene has an unsaturated benzene ring, which makes the combustion furnace structure special. It is difficult to burn all plastic waste. In particular, polyvinyl chloride (hereinafter referred to as PVC) has excellent properties and is used in various fields.
In 990, the annual production exceeded 2 million tons, and a large amount was discharged as waste. Above all, PV for agriculture
C is contaminated with mud and the like and adsorbs various odors, so that it is only partially recycled to a product with low added value and landfilled.

[0003]

However, in the landfill treatment, the problem is that the bulk density of PVC waste is small and landfill sites must be secured one after another. On the other hand, in recycling, it is difficult to widely use for various purposes due to the problem of dirt and odor as described above, and it is profitable because it can be used only for products with low added value limited to applications such as outdoor piles. Is difficult, and the current situation is that recycling is not progressing. Under the present circumstances as described above, various PVC recycling methods have been proposed. For example, Japanese Patent Laid-Open Nos. 59-11581 and 59-2.
Nos. 21341, 61-185540 and the like propose a method of dissolving in a solvent, precipitating with a non-dissolving agent, recovering and regenerating. However, these proposed recycled PVC do not refer to the separation of the plasticizer at all, and it is difficult to separate and recover the plasticizer especially when water is used as the precipitating agent. Therefore, the amount of plasticizer in recycled PVC becomes indefinite, and when the plasticizer is to be reused as a molding material, it is necessary to measure the content of the plasticizer in advance and control whether or not the plasticizer needs to be added. In addition, the solvent and the precipitant are recycled P
Since it can be mixed with VC, there is a risk of quality deterioration, and the composition control of recycled PVC is complicated and impractical.

In view of the present situation of the plastic waste treatment as described above, the present invention establishes a recycling treatment process for recycling the waste plastic to save resources and solve the waste treatment problem, and is industrially used. The purpose is to convert. Further, in recycling, it is an object to obtain a high-value-added recycled product close to a virgin raw material. Initially, the inventors of the present invention used PV for the above-mentioned agricultural purposes and other large amounts of PV, which were discarded.
For the purpose of recycling C, the treatment method thereof was earnestly studied. As a result, they have found a recycling method for separating and recovering a PVC component and a plasticizer from waste PVC in high yield and with high purity. That is, the recycled PVC component can be used as high-purity PVC, as a vinyl chloride resin product, as a carrier such as an adsorbent, a separating agent, a catalyst, and as an additive for building materials and road paving materials, while the recovered plasticizer is It can be used as an additive and fuel for vinyl chloride resin products. The present invention has found a method for recycling the above PVC waste, and further
It is applicable to the recycling of all thermoplastic resin waste that is not suitable for combustion.

[0005]

According to the present invention, there is provided a process for treating a thermoplastic resin waste, which comprises (1) a resin dissolving step of dissolving the thermoplastic resin waste in a solvent, and (2) the resin dissolving step. A solids removing step of removing solids from the solution of the step, (3) a resin precipitation step of mixing the resin solution from which the solids are removed and a precipitation agent to precipitate a thermoplastic resin, (4) precipitation of a resin precipitation solution A resin separation step of making a resin and a resin separation liquid, (5) a resin recovery step of suction-desorbing the deposit of the deposited resin, and then drying to recover the thermoplastic resin; and (6) the resin separation liquid From the solvent, the precipitant and the plasticizer, and the solvent and the precipitant are circulated to the dissolving step and the precipitating step, respectively, and a plastic separating solution treatment step for recovering the plasticizer. Resin waste treatment process There is provided.

According to the present invention, a plasticizer compatible with the precipitating agent is positively added and treated in the resin dissolving step as needed, and the plasticizer recovered in the resin separating solution step is subjected to the resin dissolving step. It is used by circulating it. In the present invention, the resin precipitation step is one in which the resin solution and the precipitant are continuously supplied to a high-speed rotary mixing device for processing, or the resin solution is atomized and sprayed into the precipitant. Is preferably supplied to In this case, the atomization spray is preferably a method in which a double ring nozzle is used to eject the resin solution from the inner ring part and let the solvent or gas flow out from the outer ring part. Further, in the resin recovery step, preferably, the deposited resin is formed so that a hollow tube having a plurality of perforated holes on a peripheral surface and covered with a felt-like absorbent is rotatable and capable of sucking the inside. To the suction desorption device equipped with the squeeze roller, the adhering substances are continuously sucked and desorbed to collect the plasticizer, the solvent and the precipitating agent from the outside of the system. It is a fluidized process under reduced pressure. Furthermore, the present invention provides that the solvent and the plasticizer are compatible with the precipitant, and the solubility parameter of the precipitant (δ _D ) and the solubility parameter of the resin (δ _P )
And the difference (δ _D −δ _P ) is −1.8 to −2.5 or +
Those of 1.2 to +3.7 are preferable. The solubility parameter is a parameter that has been studied to numerically indicate the degree of difficulty of dissolving a plastic material in a solvent by using a thermodynamic method. It is well-known because it is defined for each plastic and solvent. It is a value, and in the present invention, the value described in “Technical Data”, Volume 72, page 6 issued by Mitsubishi Oil Co., Ltd. is used.

[0007]

The present invention is constituted as described above, and dissolves the thermoplastic resin waste in a predetermined solvent and removes the insoluble solid matter, and then deposits the resin component mixed with the predetermined precipitant at the same time. , The contained plasticizer is eluted into the precipitant and extracted from the resin component, and the resin component and the plasticizer are separated into a precipitate and a solution, so that they can be respectively recovered and recycled, and
When a predetermined solvent and a precipitating agent used for the treatment, and further, if necessary, a plasticizer is added to form a resin solution, the plasticizer may also be recovered and recycled to each use step for reuse. it can. To mix the precipitant and the resin solution, both are supplied to a high-speed rotary mixing device, and the resin solution is mixed with the precipitant while being atomized under shearing force, or sprayed under pressure from a double ring nozzle. By adopting a system in which the resin solution is made into fine particles and supplied to the precipitant and mixed, the precipitation of the resin component and the separation of the plasticizer can be continuously performed, which simplifies the apparatus.
Mass processing is possible. Furthermore, high-dispersion mixing into the precipitating agent is promoted, the precipitating agent easily penetrates into the resin solution, and the solvent, precipitating agent and plasticizer rarely remain in the precipitating resin. It is possible to obtain a pure thermoplastic resin component and a plasticizer in high yield.

When the resin solution is made into fine particles and highly dispersed and mixed in the precipitant as described above, most of the precipitated resin becomes granular or powdery, and the subsequent handling is easy. That is, as a pretreatment for drying the deposited resin component, a large amount of the solvent remaining on the surface of the resin component, the depositing agent and the plasticizer,
It can be removed by suction desorption treatment in advance, and in particular, by easily removing the plasticizer having a high boiling point, the resin component can be prevented from agglomerating and the load of the drying treatment can be reduced. Further, the drying treatment can be carried out under reduced pressure in a fluidized state, the temperature can be easily controlled to be constant at any of room temperature and heating, and uniform drying can be efficiently performed because the whole resin content is stirred. be able to. Furthermore, by making the solvent and the plasticizer compatible with the precipitant, the dissolved thermoplastic resin can be efficiently precipitated, and the effect of separating the plasticizer from the thermoplastic resin is enhanced. In addition, the solubility parameter (δ _D ) of the precipitating agent is set in the range of -1.8 to -2.5 smaller than the solubility parameter (δ _P ) of the dissolved plastic resin, or 1.2 to 3.7 larger. When the content is within the range, the plasticizer can be separated from the resin component in a high yield, and the thermoplastic resin component precipitated due to the template effect associated with the elution of the plasticizer at the time of deposition becomes porous and of high purity. The thermoplastic resin deposited in a porous state has improved quality and is suitable for application in various fields. Furthermore, depending on the content of the plasticizer in the resin to be treated, the plasticizer can be appropriately added when the resin is dissolved, and can be collected and recycled. Further, in the present invention, even when the odor of the thermoplastic resin waste to be treated is significant, the odor component is dissolved in the solvent or the precipitating agent and the odor is reduced, which is preferable.

[0009]

Embodiments of the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to the following examples. FIG. 1 is a process flow explanatory diagram of an embodiment of the present invention. In FIG. 1, a raw material thermoplastic resin waste is crushed in advance so as to be easily dissolved in a solvent and held in a raw material hopper 1. If the waste is contaminated with sludge or the like, it is preferable to wash it with water or the like and dry it before crushing. The size of the crushed pieces is especially
Not limited. It may be appropriately selected depending on the types of the thermoplastic resin and the solvent, and is usually about 0.5 to 2 cm square. The thermoplastic resin of the present invention is a synthetic resin containing a plasticizer such as PVC, polyvinyl acetate, polyvinylidene chloride, or polyvinyl alcohol, or a homopolymer before the plasticizer such as PVC is added, polystyrene, or polymeta A synthetic resin containing no plasticizer such as acrylate, which is compatible with the ordinary plasticizer used in the above PVC, can be suitably treated. Further, the waste in the present invention includes not only thermoplastic resin waste but also poorly molded waste, homopolymer of thermoplastic resin raw material, and the mixture thereof.

A crushed piece of thermoplastic resin waste is extracted from the bottom of the raw material hopper 1 using a rotary feeder or the like, and a predetermined amount, usually, is put in a dissolving tank 2 equipped with a stirrer and filled with a solvent in advance.
It is supplied so that the resin concentration is 0.25 to 15% by weight. In the dissolution tank 2, the solvent is heated to a temperature near its boiling point after a predetermined amount of resin waste is supplied or before the resin waste is supplied, and dissolves the resin waste while stirring. At this time, in order to increase the porosity of the precipitated resin, it is possible to further add a plasticizer, such as the amount of the plasticizer contained in the waste thermoplastic resin to be treated. In this case, the supply and dissolution of the resin waste can be performed continuously, but when each is performed in a batch system, the dissolution of the resin waste takes a considerable time, usually depending on the amount of the resin waste and the solvent. However, since it takes about 30 to 60 minutes, when the subsequent treatment is to be continued, a plurality of dissolving tanks may be provided, and a plurality of resin dissolving steps may be provided so as to be continuous. The solvent is appropriately selected from those capable of dissolving the thermoplastic resin to be treated and the plasticizer contained therein.
Regarding the solubility of a resin in a solvent, generally, those having solubility parameters (SP) values which are close to each other in the resin and the solvent tend to be easily dissolved. However, even if there are many exceptions and the SP value is used, it is difficult to predict completely,
The solvent is appropriately selected from conventionally known solvents and solvents that have been empirically found through trial and error according to the types of the thermoplastic resin waste to be treated. Further, the solvent of the present invention is selected to be compatible with the precipitation medium described later. Normally, PVC is 1,2-dichloroethane, cyclohexanone,
Methyl ethyl ketone, methyl isobutyl ketone, dioxane and the like are preferable, and if polystyrene, xylene,
Toluene, benzene, chloroform, acetone, methyl ethyl ketone, dioxane and the like are preferable.

After the resin waste is dissolved in the dissolution tank 2, the dissolution tank 2
The solution is extracted together with the insoluble solid matter from the bottom of the solution, and the solution is sent to the solid-liquid separator 3 such as a filter or a cyclone. After the insoluble solid matter is removed by the solid-liquid separator 3, the resin solution is sent to the resin precipitation step. To enter. In the resin precipitation step, the resin solution and the depositing agent are continuously supplied to the high-speed rotation mixing device 4 that applies a shearing force to the contents while rotating at a high speed, and the resin solution and the depositing agent are both supplied by the shearing force. At the same time as being finely divided into a highly dispersed state, the resin content is granular and the average diameter of the powder is about 0.5 to
It deposits in the form of small pieces of 5 mm. When the resin solution contains a plasticizer compatible with the resin in an amount of about 0.1 to 1.2 by weight, the precipitated resin becomes more pure and porous.
This is because the plasticizer acts as a kind of template. As described above, it is also possible to positively add a plasticizer depending on the content of the plasticizer in the treated thermoplastic resin, and to treat the above-mentioned weight ratio. Examples of the plasticizer include dibutyl phthalate (DBP), dihexyl phthalate, dioctyl phthalate (DOP), didodecyl phthalate (DD).
A resin that is compatible with the resin such as P) and also with the precipitation medium is selected.

In the resin precipitation step of the present invention, the resin solution to be supplied is mixed in the precipitant in a highly dispersed state, that is, in a finely divided state, and the resin precipitation rate and the plasticizer and solvent elution rate are Any method may be used as long as the solvent and the plasticizer in the solution can be easily eluted from the resin to the depositing agent in a balanced manner, and the method is not limited to the high speed rotation device 4. For example, the resin solution may be jetted under pressure to be atomized and supplied to the depositing agent. In this case, a double ring nozzle is further used to supply the resin solution to the inner ring portion and the solvent and / or gas of the resin solution to the outer ring portion so that the resin solution ejection port and the depositing agent do not come into contact with each other. It is possible to prevent clogging of the ejection port and ensure stable continuous operation. The precipitating agent used in the resin precipitating step of the present invention is appropriately selected from those which are incompatible with the dissolved thermoplastic resin of the resin solution and compatible with the plasticizer and the solvent.
This is because when the solvent and the precipitation medium are incompatible, the dissolved resin cannot be precipitated even if the resin solution and the precipitation agent are mixed. Further, when the plasticizer and the precipitation medium are incompatible, the extraction of the plasticizer is reduced, the separation between the dissolved resin and the contained plasticizer is deteriorated, and the purity of the precipitated resin is lowered, which is not preferable. Moreover, when it is desired to obtain the precipitated resin in a porous form, the purpose cannot be achieved. Further, in the case of supplying the atomized spray by the above-mentioned pressure jet, it is generally preferable that the specific gravity of the precipitation medium is smaller than the specific gravity of the solvent. This is because when the resin solution is spray-supplied into the precipitation medium from above, spontaneous precipitation causes the resin precipitation and the plasticizer elution to be balanced, and a highly pure and porous resin can be precipitated.

The thermoplastic resin and the precipitation medium used in the above-mentioned thermoplastic resin waste treatment process have respective solubility parameter SP values, that is, the solubility parameter (δ _P ) of the plastic and the solubility parameter (δ) of the precipitation medium. difference between _{D) (δ D -δ P)} is -1.8～-
It is preferably selected to be within the range of 2.5 or 1.2 to 3.7. For example, when the thermoplastic resin is PVC or polystyrene, methanol, ethanol, n-hexane or the like is usually used as the precipitation medium.
Moreover, you may use the mixed medium of these precipitation media and the solvent of a resin solution. For mixed medium, by varying the mixing ratio can be suitably adjusted the (δ _D -δ _P) value, preferred. When the precipitation medium whose (δ _D −δ _P ) in the region close to δ _P outside the above range is within the range of −1.8 to 1.2, the yield of plastics decreases, while δ _P When a precipitation medium having a (δ _D −δ _P ) far from -2.5 or 3.7 is used, a plasticizer remains in the precipitated plastic, the purity is low, and it does not become porous. .

The depositing solution in which the resin is deposited is then supplied to the filter 5 to separate the depositing resin from the solution. The separated precipitated resin is then supplied to the suction / desorption device 6. In the suction / desorption device 6, for example, at least a pair of hollow containers each having a plurality of perforated holes on the peripheral surface and covered with a felt-like absorbent member are rotated in contact with each other, and the inside of the hollow container is sucked under reduced pressure. When the deposited resin passes between the squeeze rollers, the plasticizer, solvent, and depositing agent remaining on the surface of the deposited resin are suction-desorbed, withdrawn from the hollow tube, and collected in the intermediate tank 8. It The precipitated resin, in which the plasticizer is mainly sucked and desorbed, is further fed into the fluidized-drying device 7. The fluidized-drying device 7 introduces a heating gas such as air heated from room temperature to about 100 ° C. from below, sucks it with a blower or the like from above, and dries while flowing the deposited resin on the support plate under reduced pressure. The dried precipitated resin is appropriately extracted from the drying device 7. Further, the solvent, the depositing agent, and the like mixed in the exhaust gas are cooled, condensed, separated by the gas-liquid separator, and collected in the intermediate tank 8.

In the present invention, an apparatus in which the suction / desorption apparatus 6 and the fluidized-drying apparatus 7 are integrated can be used. For example, a plurality of squeeze rollers each having the above-described configuration are connected to a suction pipe and are arranged at one or two or more predetermined beam ends in a fluidized bed formed by blowing heated gas into the deposited resin to form a beam. It is possible to use, for example, a device that rotates or connects a plurality of the squeeze rollers to a horizontal suction pipe and rotates the suction pipe to bring it into contact with the fluid deposition resin. Also in these devices, the plasticizer and the like desorbed by the squeeze roller can be collected in the intermediate tank 8 through the suction pipe. The solvent, the precipitant and the plasticizer recovered in the intermediate tank are, for example, fed into the distillation column 9 and subjected to a distillation treatment, separated, and stored in each solvent tank 10, the precipitant tank 11 and the plasticizer tank 12, respectively. Provide for reuse. For example,
The plasticizer may be taken out of the system and further purified and reused as a plasticizer.Also, when treating a thermoplastic resin waste that does not sufficiently contain a plasticizer such as polystyrene, a precipitated resin is used. It may be used by adding it to the resin solution in order to improve the porosity. The solvent and the precipitant are
It can be circulated and used in the dissolution tank 2 and the high-speed rotary mixing device 4, respectively.

Further, in the present invention, when the waste thermoplastic resin has an odor, most of the odor usually moves into the solvent or the precipitant, and the resin is deodorized and can be recovered by precipitation. On the other hand, the resin separation solution which has absorbed the odorous component can remove the malodor and the like by appropriately disposing a deodorizing step having a deodorant in the stripping deodorizing process and the separating process of each component. For example, a deodorizing device X, for example, a device filled with a deodorizing agent such as activated carbon is provided in the outflow passage of each fraction from the distillation column 9 for distilling and separating the recovered solvent and the depositing agent in the above process, and the solvent and the depositing agent The odor in the agent can be removed.

FIG. 2 is a flow chart for explaining another embodiment of the present invention. In FIG. 2, mixed contact between the resin solution and the depositing agent is carried out in the depositing tank 14 in which a plurality of double ring nozzles are arranged in the vapor phase portion above the depositing agent liquid surface to remove the deposits of the depositing resin. Drying is performed in the same tank by using a fluidization desorption / drying device 16 in which a squeeze roller is arranged in a fluidized bed in which the precipitated resin is fluidized, and the liquid separation tank 1 is used instead of the intermediate tank.
7 and a flash drum 18 are installed, and the same as in FIG. 1 except that water extraction, distillation, and separation by flash are enabled depending on the types of solvent and precipitant. In addition, the same reference numerals are given to those having the same functions as those in FIG.

Example 1 Soft PVC sheet waste was treated by the treatment process shown in FIG. 1 above. First, the soft PVC sheet waste after sludge removal, which had been thoroughly washed with water and dried, was crushed into about 1 cm square using a rotary shearing crusher, and the crushed PVC was supplied to the raw material hopper 1. Further, the plasticizer in the waste of the flexible PVC sheet was measured by infrared spectroscopy, and the DOP was about 5
The content was 0% by weight. Dioxane 9k as solvent
The dissolution tank 2 filled with g was heated and maintained at 93 ° C., and about 1 kg of crushed PVC was fed from the raw material hopper 1 through the rotary feeder for 1 hour while stirring to melt the material.
It took about 1 hour to dissolve all the crushed PVC. Then, the PVC solution is supplied together with the insoluble solids from the bottom of the dissolution tank 2 to the solid-liquid separator 3 at a flow rate of about 10 kg / hr through the rotary feeder to separate the mixed insoluble solids from the bottom. It was extracted and removed. About 1 solid is removed
It was 50 g. On the other hand, the PVC solution is a solid-liquid separator 3
N-supplied from the precipitating agent tank 11 at a rate of 30 kg / hour into the high-speed rotary mixer 4 at a rate of 10 kg / hour.
Highly dispersed and mixed with hexane at 50 ° C., a rotation speed of 850 rpm, and a residence time of 1 minute to deposit small PVC particles. At this time, the solvent tank 1 is appropriately added to each of the PVC solution inlet and the depositing agent n-hexane supplied to the high-speed rotary mixer 4.
From 0, dioxane can be added to prevent clogging of the PVC solution inlet and adjust the solubility parameter (δ _D ) of the precipitating agent. The PVC precipitation solution dispersed and mixed in the high-speed rotary mixer 4 then flowed into the filter 5 at 670 g / min to separate into a precipitation PVC and a solution. Precipitated PVC is separated and discharged at 0.67 kg / hour, and PVC separation solution is 3
It was discharged at 9.18 kg / hour and stored in the intermediate tank 8.

The deposited PVC separated by the filter 5 is supplied to a suction / desorption device 6 provided with a squeeze roller, and the surface-adhering plasticizer and the like are desorbed by vacuum suction at about -300 mm (water column), and then desorbed. , Fluidized drying device 7 extracted from the bottom
And fluidized and dried at about 70 ° C. Fluid drying is 80 ℃
Of heated air at a flow rate of about 20 m ³ / min. The total amount of the plasticizer, the solvent and the precipitant obtained by the suction desorption and the fluidized drying was about 0.2 kg / hour, and they were fed into the intermediate tank 8. The dried PVC was white powder having an average particle size of 2 mm and was obtained at a total amount of 0.47 kg / hour. The PVC separation solution stored in the intermediate tank 8 is 10
After heating to 0 ° C., it is supplied to the distillation column 9 to separate the plasticizer, the solvent and the depositing agent by distillation, and the solvent and the depositing agent are stored in the solvent tank 10 and the depositing agent tank 11 through the deodorizing step X, respectively. The plasticizer was stored in the plasticizer tank 12. The solvent dioxane separated from the PVC separation solution was 9 kg / hour, and the precipitation agent n-hexane was 29.8 kg.
/ H, the plasticizer DOP was 0.47 kg / h. The solvent and the depositing agent were circulated from the storage tank to the dissolution tank 2 and the high-speed rotary mixer 4, respectively.

Example 2 Soft PVC sheet waste was treated by the treatment process shown in FIG. 2 above. First, the soft PVC sheet waste after sludge removal, which had been sufficiently washed with water and dried, was crushed into about 1 cm square using a rotary shearing crusher, and the crushed PVC was supplied to the raw material hopper 1. Further, the plasticizer in the waste of the flexible PVC sheet was measured by infrared spectroscopy, and the DOP was about 5
The content was 0% by weight. The dissolution tank 2 containing 9 kg of ethylene dichloride (EDC) as a solvent was heated and maintained at 73 ° C., and the crushed PVC was crushed from the raw material hopper 1 through the rotary feeder for about 1 hour while stirring the inside of the tank.
kg was fed and dissolved. It took about 1 hour to dissolve all the crushed PVC. Then, from the bottom of the dissolution tank 2 through a rotary feeder, dissolve the PVC solution with the insoluble solids for about 10 k.
The mixture was supplied to the solid-liquid separator 3 at a flow rate of g / hour to separate the insoluble solid matter that had been mixed in, and was extracted from the bottom to the outside and removed. The amount of solid matter removed was about 200 g.

On the other hand, from the depositing agent tank, 10 kg /
Deposition tank 1 for holding 50 ° C methanol supplied at the time
PV from the solid-liquid separator 3 in the vapor phase portion above the liquid surface of the precipitating agent of No. 4
The C solution was sprayed at a pressure of 10 kg / hour through the inner ring portion of the double ring nozzle, dropped as fine particles, highly dispersed with the precipitant, and mixed and contacted. At this time, EDC was supplied from the solvent tank 10 to the outer ring portion of the double ring nozzle at 1 kg / hour. PVC with a residence time of 1 minute after the resin solution is jetted and dropped
Was precipitated, and then it was allowed to flow into the filter 5 at 347 g / min to separate the precipitated PVC and the solution. Precipitated PVC is 0.57
Separated and discharged at kg / h, PVC separation solution is 20.23
It was discharged at a rate of kg / hour and stored in the liquid separator 17. The precipitated PVC separated by the filter 5 is supplied to a fluidized-bed desorption dryer 16 equipped with a squeeze roller, and about 20 times from the bottom.
It is fluidized to 70 ° C. by heated air of 80 ° C. flowing in at a flow rate of m ³ / min, and at the same time, the surface-adhering plasticizer etc. is reduced by about −300.
While being desorbed by vacuum suction with mm (water column), it was fluidized and dried. Plasticizer obtained by this suction desorption fluidized drying,
The total amount of solvent and precipitant is about 0.1 kg / hour, and the filter 5
It was made to join with the PVC separation solution from and was sent to the liquid separator 17. The dried PVC was white powder having an average particle size of 2 mm and was obtained at a total amount of 0.47 kg / hour.

The PVC separation solution stored in the liquid separator 17 extracts methanol as a precipitating agent with water and causes the upper liquid phase of the water-methanol phase in the liquid separator 17 to overflow from the weir, so that the solvent and the plastic Separated from the agent. The separated water-methanol phase is then heated to 75 [deg.] C. and fed into the distillation column 19 to separate water and methanol by distillation to separate methanol into the depositing agent tank 1.
The water was stored in No. 1 and the water was circulated to the liquid separator 17 for reuse.
On the other hand, mainly the solvent EDC and the plasticizer DOP in the liquid separator 17
The lower liquid phase consisting of was extracted from the bottom and heated to 85 ° C., then was supplied to the flash drum 18, EDC and DOP were separated, and stored in the solvent tank 10 and the plasticizer tank 12, respectively. At this time, the solvent EDC separated from the PVC separation solution was 10 kg / hour, the precipitation agent methanol was 29.8 kg / hour, and the plasticizer DOP was 0.47.
It was kg / hour. The solvent and the depositing agent were circulated from the storage tanks 10 and 11 to the dissolving tank 2 and the depositing tank 14, respectively.

[0023]

INDUSTRIAL APPLICABILITY The present invention can treat thermoplastic resin waste continuously and stably, and can regenerate the thermoplastic resin into a highly pure and porous material. It is effective for the treatment of wastes, especially polyvinyl chloride and polystyrene that cannot be burned. Furthermore, the obtained recycled resin is highly pure and porous, and is not restricted in its use for reuse. It is useful for recycling. Further, the plasticizer can also be separated, removed, and collected for reuse.

[Brief description of drawings]

FIG. 1 is a flow explanatory diagram of an embodiment of the present invention.

FIG. 2 is a flowchart explaining another embodiment of the present invention.

[Explanation of symbols]

 1 Raw Material Hopper 2 Dissolution Tank 3 Solid-Liquid Separator 4 High Speed Rotation Mixer 5 Filtration Machine 6 Suction Desorption Device 7 Fluid Drying Device 8 Intermediate Tank 9, 19 Distillation Tower 10 Solvent Tank 11 Precipitant Tank 12 Plasticizer Tank 14 Precipitation Tank 16 Fluid desorption / drying device 17 Liquid separator 18 Flash drum

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI technical display location B29B 17/00 9350-4F C08J 11/18 7310-4F // B29K 105: 26

Claims (7)

[Claims] 1. A process for treating a thermoplastic resin waste, which comprises (1) a resin dissolving step of dissolving the thermoplastic resin waste in a solvent, and (2) a solid for removing solids from the solution of the resin dissolving step. Substance removal step, (3) resin precipitation step of mixing a resin solution from which solid matter has been removed and a precipitation agent to precipitate a thermoplastic resin, and (4) resin separation using the resin precipitation solution as a precipitation resin and a resin separation solution. Step, (5) a resin recovery step of suction-desorbing the deposit of the deposited resin and then drying to recover the thermoplastic resin, and (6) a solvent, a depositing agent and a plasticizer from the resin separated liquid, respectively. A process for treating a thermoplastic resin waste, which comprises a resin separation solution treatment step of separating and circulating a solvent and a precipitation agent to the dissolution step and the precipitation step, respectively, and recovering a plasticizer. 2. The resin dissolving step, wherein a plasticizer compatible with the depositing agent is added, and the plasticizer recovered in the resin separating solution treating step is circulated to the resin dissolving step. Thermoplastic waste treatment process. 3. The process for treating thermoplastic resin waste according to claim 1, wherein in the resin precipitation step, the resin solution and the precipitation agent are continuously supplied to a high-speed rotary mixing device. 4. The process for treating a thermoplastic resin waste according to claim 1, wherein, in the resin precipitation step, the resin solution is jetted under pressure and atomized and sprayed to be supplied into the precipitation agent. 5. The treatment of thermoplastic resin waste according to claim 4, wherein the atomized spray is made to eject the resin solution from the inner ring part and to let out the solvent or gas from the outer ring part by using a double ring nozzle. process. 6. In the resin collecting step, a hollow tube having a plurality of perforated holes in the peripheral surface and covered with a felt-like absorbent is formed so that the precipitated resin can be rotated and sucked inside. Was continuously supplied to the suction-desorption device equipped with the squeeze roller, and the adhering substances were suction-desorbed to collect the plasticizer, the solvent and the precipitant from the outside of the system, and then the suction-desorbed precipitation resin was removed. The process for treating a thermoplastic resin waste according to claim 1, wherein the process is carried out under a reduced pressure in a fluidized manner and dried. 7. The solvent and the plasticizer are compatible with the precipitant, and a difference (δ _D −δ _P ) between the solubility parameter (δ _D ) of the precipitant and the solubility parameter (δ _P ) of the resin is −
The process for treating thermoplastic waste according to claims 1 to 6, wherein the process is 1.8 to -2.5 or +1.2 to +3.7.