KR20230040545A - Manufacturing method of recycled plastics, manufacturing device of recycled plastics and recycled plastics - Google Patents

Abstract

The present invention provides a manufacturing method of recycled plastics, the recycled plastics, and a manufacturing device of the recycled plastics. The present invention is to provide the manufacturing method of the recycled plastics, which can efficiently remove additives and significantly increase the purity of the recycled plastics, the recycled plastics manufactured by the method and the manufacturing device of the recycled plastics.

Description

Recycled plastic manufacturing method, recycled plastic manufacturing device, and recycled plastic

The present invention relates to a method for manufacturing recycled plastic, an apparatus for manufacturing recycled plastic, and a recycled plastic produced by the manufacturing method.

Plastics are widely used in modern society because they are easy to process and easily change physical and chemical properties. Landfill or incineration methods are widely used to treat waste plastics that are discarded after use. However, since plastics are difficult to decompose naturally, landfilling can cause environmental problems such as water quality and soil contamination. In the case of incineration, Air pollution can cause environmental problems.

In order to solve these environmental problems, many studies have been conducted to recycle waste plastics by processing, refining, or transforming them, and some regeneration methods are actually being used.

Various additives such as stabilizers, slip agents, flame retardants, and lubricants are used in plastics to exhibit physical properties suitable for the purpose. As environmental and human harmfulness issues have emerged internationally, regulations on harmful additives that have been used have arisen. A melting/extrusion method that mechanically recycles plastics is used as a method for easily and quickly recycling plastics, but it is difficult to remove additives contained in plastics.

In addition to the above mechanical recycling method, a process of removing additives using a solvent extraction method from plastic and obtaining recycled plastic was applied. In the agitation process commonly performed in the solvent extraction method, additives cannot be effectively removed from waste plastics unless agitation is sufficiently performed.

Therefore, there is a continuous need for research on a method for manufacturing recycled plastics capable of significantly increasing the purity of recycled plastics by effectively removing additives from waste plastics.

Korean Patent Publication No. 2002-0042681

The present invention is to solve the problems of the conventional method for manufacturing recycled plastic, and is a method for manufacturing recycled plastic that can efficiently remove additives and greatly increase the purity of recycled plastic, recycled plastic produced thereby, and an apparatus for manufacturing recycled plastic. want to provide

An exemplary embodiment of the present invention comprises preparing a first solution by dissolving waste plastic in a solvent; preparing a second solution by adding a non-solvent to the first solution; preparing a third solution by adding an aqueous solution containing a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol to the second solution; precipitating a plastic raw material from the third solution and inducing phase separation of the solvent and the non-solvent; and obtaining a plastic raw material precipitated from the third solution.

An exemplary embodiment of the present invention is recycled plastic produced by the method for manufacturing recycled plastic, and provides recycled plastic having a recovery rate of 38.6% or more.

An exemplary embodiment of the present invention provides recycled plastic produced by the method for manufacturing recycled plastic, wherein the recycled plastic has an impurity of 13% or less.

An exemplary embodiment of the present invention is a first solution in which waste plastic is dissolved in a solvent, and an aqueous solution containing a non-solvent and a compound having a weight average molecular weight of 10,000 g / mol to 500,000 g / mol is added to the first solution. 3 reaction vessel for receiving the solution; and a filtration unit for obtaining the plastic raw material precipitated from the third solution in the reactor.

The method for producing recycled polyvinyl chloride and the apparatus for producing recycled polyvinyl chloride of the present invention can increase the mass productivity of recycled plastics and effectively remove additives to obtain recycled polyvinyl chloride with high purity.

1 shows an apparatus for manufacturing recycled plastic according to the present invention.

Hereinafter, specific exemplary embodiments will be described in more detail.

In the present specification, “include” means that other components may be further included without excluding other components unless otherwise specified.

An exemplary embodiment of the present invention comprises preparing a first solution by dissolving waste plastic in a solvent; preparing a second solution by adding a non-solvent to the first solution; preparing a third solution by adding an aqueous solution containing a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol to the second solution; precipitating a plastic raw material from the third solution and inducing phase separation of the solvent and the non-solvent; and obtaining a plastic raw material precipitated from the third solution.

Waste plastics contain additives such as stabilizers and plasticizers. Due to the strengthening of environmental regulations, the use of phthalate-based plasticizers or lead-based stabilizers among additives used in plastics has been prohibited, and the same regulations are applied to the production of recycled plastics.

The method for producing recycled plastic according to the present invention utilizes the difference in solubility of waste plastic in non-solvent and the difference in specific gravity between the non-solvent and an aqueous solution containing a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol. , It is possible to effectively obtain plastic raw materials from waste plastics to increase the mass productivity of recycled plastics, and to obtain recycled plastics with high purity by efficiently removing additives.

In particular, by using an aqueous solution containing a compound having a weight average molecular weight of 10,000 g / mol to 500,000 g / mol together with the non-solvent, the solubility of the plastic raw material in the non-solvent is lowered, thereby increasing the recovery rate of recycled plastic. , The compound having a weight average molecular weight of 10,000 g / mol to 500,000 g / mol is polar to help aggregation of the plastic raw material so that the plastic raw material can be better precipitated, adding a metal salt such as NaCl to the second solution In contrast, it is possible to increase the recovery rate of recycled plastic and reduce the content of impurities contained in recycled plastic.

The compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol may have a weight average molecular weight of 12,000 g/mol to 100,000 g/mol.

In one embodiment of the present invention, the weight average molecular weight (Mw) can be measured using gel permeation chromatography. Specifically, the weight average molecular weight can be measured using a THF-GPC instrument, a column of PLgel Mixed B x 2, a solvent of tetrahydrofuran (THF), a flow rate of 1.0 mL / min, and a temperature of 40 ° C. .

In one embodiment of the present invention, the term "plastic" is a general term for organic polymeric materials that have plasticity, are softened by heating, and can be molded into any shape.

The plastic is, for example, polyvinyl chloride (PVC), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyurethane (PU), polyamide (PA), polyester (PES), polyvinyl chloride It may be leaden (PVDC), polycarbonate (PC), polystyrene (PS) or polyethylene terephthalate (PET), but is not limited thereto. The plastic is preferably polyvinyl chloride (PVC).

In one embodiment of the present invention, the "waste plastic" refers to waste generated after using plastic products, and the waste may be industrial, commercial, or household waste, and used in transportation such as home appliances or automobiles. Plastics can be employed without limitation, and are not limited to any one. The waste may refer to a state in which a plastic product is no longer usable after it has been used for its intended purpose, as well as when the plastic product has been used once. In the present invention, for example, waste polyvinyl chloride may be applied.

In the present invention, "plastic raw material" means a resin that is the main raw material of the plastic.

In the present invention, the additive means various additives applied to plastic production, and may mean, for example, a plasticizer or a stabilizer. The plasticizer may be a phthalate plasticizer.

In the present invention, impurities may include the above additives, and may include calcium carbonate or heavy metals in addition to the above additives. In addition, the impurities may include inorganic materials including Ca, Mg, Ti, Al, or Zr.

In one embodiment of the present invention, the method for producing recycled plastic includes preparing a first solution by dissolving waste plastic in a solvent.

The temperature at the time of preparing the first solution is 0 ℃ to 150 ℃, preferably 60 ℃ to 80 ℃.

Based on 100 parts by weight of the solvent, the waste plastic may be included in an amount of 1 part by weight to 50 parts by weight. Preferably, the waste plastic may be included in an amount of 8 to 10 parts by weight based on 100 parts by weight of the solvent.

In one embodiment of the present invention, the solvent:non-solvent volume ratio is 1:1 to 1:50. Preferably, the volume ratio of the solvent to the non-solvent is 1:1 to 1:5.

When the solvent and the non-solvent satisfy the aforementioned volume ratio, precipitation of plastic raw materials from waste plastic is facilitated, and recycled plastic having improved purity can be obtained.

In one embodiment of the present invention, the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is polyvinyl alcohol, polyacrylic acid, poloxamer or polyvinylpyrrolidone.

Preferably, the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is polyvinyl alcohol, polyacrylic acid or poloxamer.

The compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol may be a water-soluble compound.

In one embodiment of the present invention, the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is based on 100 parts by weight of an aqueous solution containing a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol. It includes 0.5 parts by weight to 50 parts by weight.

Preferably, the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is present in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of an aqueous solution containing a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol. parts by weight, 0.5 parts by weight to 5 parts by weight or 0.5 parts by weight to 3 parts by weight.

When the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is included in the aqueous solution in the aforementioned weight part, the solubility of the plastic raw material in the non-solvent can be drastically lowered, and the compound is polar. , It can increase the coagulation rate of plastic raw materials, and can separate them from each other by using the difference in specific gravity between plastic raw materials and impurities.

In one embodiment of the present invention, the volume ratio of the first solution: the aqueous solution containing the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is 1:0.05 to 1:1.

When the first solution and the aqueous solution satisfy the aforementioned volume ratio, precipitation of plastic raw materials from waste plastic is facilitated, and recycled plastic having improved purity can be obtained.

In the step of precipitating the plastic raw material from the third solution and inducing phase separation of the solvent and the non-solvent, an aqueous solution in which the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is dissolved is added, The second solution and the aqueous solution are phase separated from the third solution through layer separation. At this time, the aqueous solution in which the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is dissolved is preferably added dropwise, and the dropping speed is not particularly limited.

Specifically, when phase separation occurs, a layer containing an aqueous solution containing a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is formed on the lower layer, and a layer containing the second solution is formed on the upper layer. The plastic raw material precipitated from the third solution may be distributed on the interface between the upper layer and the lower layer. In addition, impurities such as calcium carbonate may be distributed in the lower layer.

In one embodiment of the present invention, the step of precipitating the plastic raw material from the third solution and inducing phase separation of the solvent and the non-solvent includes stirring the third solution with a stirrer.

When the third solution is stirred by a stirrer, phase separation of the solvent and the non-solvent may be induced to occur rapidly.

In one embodiment of the present invention, stirring the third solution by a stirrer is stirring at a speed of 50 rpm to 400 rpm at a temperature of 0 ° C to 50 ° C for 1 hour to 24 hours.

When stirring by the stirrer is performed under the above conditions, phase separation of the third solution may be promoted.

In one embodiment of the present invention, the filter applied in the step of obtaining the plastic raw material precipitated from the third solution may be appropriately employed in the art and is not particularly limited. For example, the filter may have a size of 10 mesh to 500 mesh, preferably a filter of 50 mesh to 200 mesh. The filter may be included in a Buchner funnel.

In one embodiment of the present invention, the solvent is a ketone-based solvent; cyclic ether-based solvents; linear or cyclic carbonate-based solvents; or a hydrocarbon-based solvent having 1 to 10 carbon atoms.

The ketone-based solvent may be, for example, methyl ethyl ketone.

The cyclic ether-based solvent may be, for example, tetrahydrofuran.

In one embodiment of the present invention, the linear carbonate-based solvent is dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (EMC) or methyl It may be propyl carbonate (MPC), but is not limited thereto.

In one embodiment of the present invention, the cyclic carbonate-based solvent is ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate (BC), 2,3-butylene carbonate, 1,2- It may be pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate (VC), vinyl ethylene carbonate or fluoroethylene carbonate, but is not limited thereto. Preferably, the cyclic carbonate-based solvent may be propylene carbonate.

In one embodiment of the present invention, the hydrocarbon-based solvent having 1 to 10 carbon atoms may be methylene chloride or ethylene chloride, but is not limited thereto.

In one embodiment of the present invention, the solvent is preferably methyl ethyl ketone.

The non-solvent refers to a compound having a Hansen Solubility Parameter (HSP) of polyvinyl chloride of 10 or more.

In one embodiment of the present invention, the non-solvent is a hydrocarbon compound containing at least one selected from the group consisting of alcohol, ether, cycloalkane, ester, carboxylic acid, and nitrile.

In one embodiment of the present invention, the non-solvent is methanol, ethanol, acetone, ethyl acetate or acetonitrile. The non-solvent is preferably methanol.

In one embodiment of the present invention, after the step of obtaining the precipitated plastic raw material, dehydration of the plastic raw material; drying the plastic raw material; and at least one selected from the group consisting of the step of extruding the plastic raw material.

Preferably, the method for producing recycled plastic of the present invention includes, after the step of obtaining the precipitated plastic raw material, a dewatering step of the plastic raw material; drying the plastic raw material; and extruding the plastic raw material.

More preferably, the manufacturing method of the recycled plastic includes a step of drying the plastic raw material after the step of obtaining the precipitated plastic raw material.

Conditions for the dehydration step of the plastic raw material are not particularly limited, and conditions applied in the art may be appropriately employed.

Conditions for the drying step of the plastic raw material are not particularly limited, and conditions applied in the art may be appropriately employed.

The step of extruding the plastic raw material means manufacturing it into pellets using an extruder. Conditions applied when producing pellets using the extruder are not particularly limited, and conditions applied in the art may be appropriately employed.

An exemplary embodiment of the present invention is recycled plastic produced by the method for manufacturing recycled plastic, and provides recycled plastic having a recovery rate of 38.6% or more.

Specifically, the recovery rate of the recycled plastic is 38.7% or more and 45% or less, 38.7% or more and 43% or less, or 38.7% or more and 40.2% or less.

The recovery rate of the recycled plastic can be measured by NMR analysis.

Specifically, the recovery rate of the recycled plastic can be calculated by measuring the content of the resin through NMR analysis and calculating the ratio (content of the resin in the recycled plastic/content of the resin in the waste plastic) X100.

An exemplary embodiment of the present invention is recycled plastic produced by the method for manufacturing recycled plastic, and provides recycled plastic having an impurity of 13% or less.

Specifically, the impurity contained in the recycled plastic is 1% or more and 13% or less, 5% or more and 13% or less, 10% or more and 13% or less, or 10.5% or more and 12.6% or less.

The impurity contained in the recycled plastic can be measured by inductively coupled plasma emission spectrometry (ICP-OES) and gas chromatography mass spectrometry (GC-MS).

The impurity contained in the recycled plastic was determined by measuring the impurity content by inductively coupled plasma emission spectrometry (ICP-OES) and gas chromatography mass spectrometry (GC-MS), (impurity content/yield of recycled polyvinyl chloride) X 100 can be calculated as

When the impurity contained in the recycled plastic according to the present invention satisfies the above range, it can be seen that the purity of the recycled plastic is greatly improved by applying the method for manufacturing recycled plastic according to the present invention.

An exemplary embodiment of the present invention is a first solution in which waste plastic is dissolved in a solvent, and an aqueous solution containing a non-solvent and a compound having a weight average molecular weight of 10,000 g / mol to 500,000 g / mol is added to the first solution. 3 reaction vessel for receiving the solution; and a filtration unit for obtaining the plastic raw material precipitated from the third solution in the reactor.

In one embodiment of the present invention, the reaction vessel further includes a stirrer for stirring the third solution.

The description of the manufacturing apparatus of the recycled plastic may be applied to the description applied to the manufacturing method of the above-described recycled plastic.

In one embodiment of the present invention, the apparatus for producing the recycled plastic includes a dewatering unit for dehydrating the plastic raw material obtained from the filtering unit; a drying unit for drying the plastic raw material; And it may further include at least one selected from the group consisting of an extrusion unit for extruding the plastic raw material.

1 shows an apparatus for manufacturing recycled plastic according to an exemplary embodiment of the present invention. The apparatus for manufacturing recycled plastic is a product obtained by adding a first solution in which waste plastic is dissolved in a solvent, and an aqueous solution containing a non-solvent and a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol to the first solution. It includes a reaction tank (1) accommodating three solutions and a filtering part (2) for obtaining the plastic raw material precipitated from the third solution in the reaction tank. The reaction tank 1 may further include an agitator 10 for agitating the third solution. In the agitator 10, at least one or more propellers may be positioned on a long rod along a longitudinal direction of the rod. The agitator 10 may include a motor capable of providing power to rotate the propeller. That is, the stirrer 10 includes a motor, a rod, and one or more propellers, and the motor and the rod may be connected to each other. Although not specifically shown in FIG. 1, a filter is applied to the filtering unit 2, and the filter described above in the manufacturing method of the recycled plastic is applied.

Hereinafter, the present invention is illustrated in more detail through examples. The present invention is not limited by these examples, and the embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the examples detailed below. . The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Examples and Comparative Examples.

Example 1

Waste polyvinyl chloride, which is waste plastic, was added to 1 L of methyl ethyl ketone and dissolved at 70° C. for 1 hour to prepare a first solution, and then the first solution was filtered through a 60 mesh filter. The first solution was prepared to contain 10 parts by weight of waste plastic based on 100 parts by weight of methyl ethyl ketone.

A second solution was prepared by adding droplets of 2L of methanol, a non-solvent, to the filtered first solution.

Thereafter, an aqueous solution containing polyvinyl alcohol (PVA) having a weight average molecular weight of 60,000 g/mol was prepared in the second solution, and 100 ml of the aqueous solution was added dropwise to prepare a third solution. A plastic raw material was precipitated from the third solution, and phase separation between methyl ethyl ketone and methanol was induced. The aqueous solution was prepared to include 2 parts by weight of polyvinyl alcohol based on 100 parts by weight of the aqueous solution.

When the plastic raw material was precipitated from the third solution, it was stirred at 200 rpm at 25° C. for 1 hour using a stirrer, and after stirring, the plastic raw material precipitated was allowed to stand for 1 hour.

Thereafter, the plastic raw material precipitated from the third solution was obtained using a Buchner funnel including a 100 mesh filter, and dried at 60° C. for 24 hours to obtain recycled polyvinyl chloride, which is a recycled plastic.

Example 2

In Example 1, in the same manner as in Example 1, except that polyacrylic acid (PAA) having a weight average molecular weight of 100,000 g/mol was applied instead of polyvinyl alcohol (PVA) having a weight average molecular weight of 60,000 g/mol. Recycled polyvinyl chloride was obtained.

Example 3

In Example 1, a poloxamer (EO ₁₀₀ PO ₆₄ EO ₁₀₀ ) having a weight average molecular weight of 12,000 g/mol was used instead of an aqueous solution containing 2% by weight of polyvinyl alcohol (PVA) having a weight average molecular weight of 60,000 g/mol. Recycled polyvinyl chloride was obtained in the same manner as in Example 1, except that an aqueous solution containing 0.5% by weight was applied.

Comparative Example 1

Waste polyvinyl chloride, which is waste plastic, was added to 1 L of methyl ethyl ketone and dissolved at 70° C. for 1 hour to prepare a first solution, and then the first solution was filtered through a 60 mesh filter. The first solution was prepared to contain 10 parts by weight of waste plastic based on 100 parts by weight of methyl ethyl ketone.

A second solution was prepared by adding droplets of 2L of methanol, a non-solvent, to the filtered first solution.

The second solution was stirred for 1 hour using a stirrer, and left for 1 hour after stirring to settle the precipitated plastic material.

Thereafter, the plastic raw material precipitated from the second solution was obtained using a Buchner funnel, and dried at 60° C. for 24 hours to obtain recycled polyvinyl chloride, which is a recycled plastic.

Comparative Example 2

Waste polyvinyl chloride, which is waste plastic, was added to 1 L of methyl ethyl ketone and dissolved at 70° C. for 1 hour to prepare a first solution, and then the first solution was filtered through a 60 mesh filter. The first solution was prepared to contain 10 parts by weight of waste plastic based on 100 parts by weight of methyl ethyl ketone.

A second solution was prepared by dropping 2L of methanol, a non-solvent, in droplets on the filtered first solution, and 10% by weight of NaCl based on the total weight of the second solution was added to the second solution .

The second solution to which NaCl was added was stirred for 1 hour using a stirrer, and left for 1 hour after stirring to settle the precipitated plastic material.

Thereafter, the plastic raw material precipitated from the second solution was obtained using a Buchner funnel, and dried at 60° C. for 24 hours to obtain recycled polyvinyl chloride, which is a recycled plastic.

Comparative Example 3

In Comparative Example 2, except that 20% by weight of NaCl was applied based on the total weight of the second solution instead of adding 10% by weight of NaCl based on the total weight of the second solution to the second solution. Recycled polyvinyl chloride was obtained in the same manner as in Comparative Example 2.

Comparative Example 4

In Comparative Example 3, recycled polyvinyl chloride was obtained in the same manner as in Comparative Example 3, except that KCl was applied instead of NaCl.

experimental example.

The recovery rate of recycled polyvinyl chloride was measured by NMR analysis of the recycled polyvinyl chloride prepared by applying the method for manufacturing recycled plastic according to the above Examples and Comparative Examples, and inductively coupled plasma emission spectrometry (ICP-OES) and gas chromatography were performed. The impurity contained in the recycled polyvinyl chloride was measured by mass spectrometry (GC-MS), and it is shown in Table 1 below.

Recovery rate of recycled polyvinyl chloride

Dimethylformamide (DMF), an internal standard, was added to 0.1 g of waste polyvinyl chloride samples applied in Examples and Comparative Examples and 0.1 g of regenerated polyvinyl chloride samples prepared according to Examples and Comparative Examples to deplete heavy water. After dissolving in digested tetrahydrofuran (THF-d8) at 298K (24.85 ° C) and measuring 1H-NMR, the content of each polyvinyl chloride resin was calculated based on the integral value of the spectrum. The recovery rate of recycled polyvinyl chloride was calculated by (content of polyvinyl chloride resin contained in recycled polyvinyl chloride / content of polyvinyl chloride resin contained in waste polyvinyl chloride) X 100 and listed in Table 1 below.

Impurity contained in recycled polyvinyl chloride

0.1 g of the regenerated polyvinyl chloride sample according to Examples and Comparative Examples was put into 2 ml of sulfuric acid and heated to carbonize. When this was repeated and the sample became clear and transparent, sulfuric acid was removed by evaporation, leaving only about 1 mm. When the sample turned orange again, it was decomposed by adding 0.5 ml of nitric acid and hydrogen peroxide. When the sample was completely dissolved clearly, it was diluted to 10 ml with tertiary ultrapure water to prepare an analysis sample. Inorganic content including Ca, Mg, Ti, Al or Zr was calculated by measuring ICP-OES with the prepared analysis sample.

After dissolving 1 g of the regenerated polyvinyl chloride sample according to Examples and Comparative Examples in 10 ml of tetrahydrofuran, 40 ml of methanol was injected and stirred at room temperature for 6 hours, and then the supernatant was separated and GC-MS was measured to determine the phthalate plasticizer content with a spectrum. Calculated.

This was calculated as (impurity content/yield of recycled polyvinyl chloride) X100 and listed in Table 1 below. In this case, the impurity content refers to the previously calculated inorganic content and plasticizer content.

Recovery rate of recycled PVC (%) Impurity of recycled PVC (%) Example 1 40.2 10.5 Example 2 39.6 11.2 Example 3 38.7 12.6 Example 4 39.2 12.2 Comparative Example 1 24.4 25.2 Comparative Example 2 33.8 21.2 Comparative Example 3 38.3 18.9 Comparative Example 4 35.6 19.2

According to Table 1, it was confirmed that the recovery rate of recycled polyvinyl chloride was higher in the examples according to the present invention and the impurity of the recycled polyvinyl chloride was lower than in the comparative examples.

Accordingly, it was confirmed that, in the case of manufacturing recycled plastic by applying the method for manufacturing recycled plastic according to the present invention, it is possible to efficiently remove additives from waste plastic and obtain recycled plastic having improved purity.

1: reactor
2: filtering unit
10: agitator

Claims (14)

preparing a first solution by dissolving the waste plastic in a solvent;
preparing a second solution by adding a non-solvent to the first solution;
preparing a third solution by adding an aqueous solution containing a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol to the second solution;
precipitating a plastic raw material from the third solution and inducing phase separation of the solvent and the non-solvent; and
A method for producing recycled plastic comprising the step of obtaining a plastic raw material precipitated from the third solution. The method of claim 1, wherein the step of precipitating the plastic raw material from the third solution and inducing phase separation of the solvent and the non-solvent comprises stirring the third solution with a stirrer. . The method of claim 1, wherein the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is polyvinyl alcohol, polyacrylic acid, poloxamer, or polyvinylpyrrolidone. The method according to claim 1, wherein the solvent is a ketone-based solvent; cyclic ether-based solvents; linear or cyclic carbonate-based solvents; Or a method for producing recycled polyvinyl chloride that is a hydrocarbon-based solvent having 1 to 10 carbon atoms. The method of claim 1, wherein the non-solvent is a hydrocarbon compound containing at least one selected from the group consisting of alcohol, ether, cycloalkane, ester, carboxylic acid, and nitrile. The method of claim 2, wherein the stirring of the third solution by the stirrer is stirring at a speed of 50 rpm to 400 rpm at a temperature of 0 ° C to 50 ° C for 1 hour to 24 hours. The method according to claim 1, after the step of obtaining the precipitated plastic raw material, a dehydration step of the plastic raw material; drying the plastic raw material; and at least one selected from the group consisting of extruding the plastic raw material. The method according to claim 1, wherein the solvent:non-solvent volume ratio is 1:1 to 1:50. The method according to claim 1, wherein the compound having a weight average molecular weight of 10,000 g / mol to 500,000 g / mol
Method for producing a recycled plastic that contains 0.5 parts by weight to 50 parts by weight based on 100 parts by weight of an aqueous solution containing a compound having a weight average molecular weight of 10,000 g / mol to 500,000 g / mol. The method according to claim 1, wherein the volume ratio of the first solution to the aqueous solution containing the compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is 1:0.05 to 1:1. Recycled plastic produced by the method of manufacturing recycled plastic according to any one of claims 1 to 10, wherein the recovery rate of recycled plastic is 38.6% or more. Recycled plastic produced by the method of manufacturing recycled plastic according to any one of claims 1 to 10, wherein the recycled plastic has an impurity of 13% or less. A reaction tank accommodating a first solution in which waste plastic is dissolved in a solvent and a third solution in which an aqueous solution containing a non-solvent and a compound having a weight average molecular weight of 10,000 g/mol to 500,000 g/mol is added to the first solution; and
An apparatus for manufacturing recycled plastic comprising a filtering unit for obtaining a plastic raw material precipitated from the third solution in the reaction tank. The apparatus for manufacturing recycled plastic according to claim 13, wherein the reaction tank further comprises an agitator for agitating the third solution.

Images