TW202402498A - Plastic recycling method capable of recycling and reusing the solvent to reduces cost and avoid environmental problems - Google Patents

Abstract

The present invention provides a plastic recycling method, which uses a solvent in a heating step to dissolve the recycling target substance, and separates the solvent and the recycling target substance through negative pressure. In addition to having a high plastic recovery rate, the plastic recycling method of the present invention not only reduces costs but also avoids environmental problems since the solvent can be recycled and reused.

Description

Plastic recycling methods

The invention relates to a plastic recycling method, in particular to a plastic recycling method for recycling polypropylene.

The invention of plastic began in the 19th century. Due to its advantages of low production cost and high stability, it is widely used as the main material of daily necessities. For example, polypropylene (PP) has the advantages of heat resistance, acid and alkali resistance, and good toughness. , so it is widely used in beverage bottles, straws, microwaveable containers and trash cans, etc. In addition, PP has a lower cancer risk than other plastic materials, so it is widely used in food containers.

Since plastic is not easily decomposed in nature, it gradually causes environmental problems, especially single-use plastic bags or PET bottles and other containers. Current plastic recycling methods include: (1) Melt regeneration method: by recycling clean leftover materials from processing plants and reshaping them into recycled plastic; or recycling mixed plastic products for compound regeneration; and (2) Thermal cracking method : Recycle specific plastics into fuel. For example: Taiwan Patent Announcement No. TWI254115B cracks waste plastic into liquid oil and combustible gas.

Although countries are gradually implementing plastic reduction policies, the environmental problems caused by plastic waste still need to be solved urgently, so it is necessary to develop new plastic recycling methods.

In order to solve the above problems, the present invention provides a plastic recycling method, which includes: (1) Preparation step: prepare a plastic-containing material, the plastic-containing material contains a plastic, and the plastic contains polypropylene (PP); (2) Mixing step: mix the plastic material and a solvent to obtain a first mixture, wherein the plastic can be dissolved in the solvent; (3) Heating step: heat and stir the first mixture at a temperature of 80 ^○ C to 140 ^○ C, The plastic is dissolved in the solvent to obtain a solution; and (4) separation step: placing the solution into a negative pressure environment to obtain the plastic.

According to the present invention, first, a solvent is used to dissolve plastic as the recycling target, thereby achieving a high plastic recovery rate. Second, heating and stirring help dissolve the plastic, which can increase the plastic recycling rate. Third, evaporating the solvent in a negative pressure environment can not only effectively separate the solvent and the plastic that is the target of recycling, but also prevent the solvent or plastic from deteriorating due to overheating, so that the recycled solvent can also be reused. In order to further reduce recycling costs, this can not only attract more manufacturers to invest in the plastic recycling industry, but also avoid the cost increase and potential environmental problems caused by the discharge of solvents, so it can double reduce environmental problems.

The plastic-containing material of the present invention includes polymers, mixtures or combinations thereof.

According to the present invention, in the heating step, when the temperature is greater than 140 ^° C, the solution will begin to boil.

In one embodiment, the separation step further includes: insulating the solution at a temperature of 70 ^○ C to 100 ^○ C. The present invention reduces the boiling point of the solvent by creating a negative pressure environment, and maintains the solvent in a boiling state through heat preservation, thereby facilitating accelerated and stable recovery of the solvent and having the advantage of reducing energy consumption.

In an implementation, in the separation step, the pressure of the negative pressure environment is greater than or equal to 0 mbar and less than or equal to 90 mbar, such as: 1 mbar, 10 mbar, 30 mbar, 50 mbar. bar, 70 mbar or 90 mbar. Preferably, the pressure of the negative pressure environment is greater than or equal to 0 mbar and less than or equal to 20 mbar.

In one embodiment, the separation step lasts from 5 minutes to 1 hour. Preferably, when the pressure of the negative pressure environment is greater than or equal to 0 mbar and less than or equal to 20 mbar, the time of the separation step is 10 minutes to 20 minutes; and/or when the pressure of the negative pressure environment is When greater than 20 mbar and less than or equal to 80 mbar, the time of this separation step is from 20 minutes to 40 minutes.

In one embodiment, the plastic recycling method of the present invention does not use a precipitant to separate the plastic.

In one embodiment, the solvent includes any one of aromatic hydrocarbons, ketones, ethers, cycloalkanes, esters, or a combination thereof.

Preferably, the esters include alkyl esters.

Preferably, the aromatic hydrocarbon includes any one of benzole, toluene, xylene, tetralin, decalin or a combination thereof.

The above-mentioned xylene has the advantage of relatively low toxicity.

In an embodiment, in the mixing step, a solvent mutual solution is further added, and the solvent mutual solution contains any one of ether, ketone, lipid or a combination thereof.

Preferably, the ether contains tetrahydrofuran.

Preferably, the ketone includes cyclohexanone, acetone or a combination thereof.

Preferably, the ester includes any one of propylene glycol methyl ether acetate, butyl acetate, isoamyl acetate or a combination thereof.

According to the present invention, the "solvent miscible solution" is a liquid that is miscible with the solvent, and the use of the solvent miscible solution can reduce the usage of solvent while maintaining a high recovery rate, which helps to reduce costs, toxicity and improve environmental friendliness. degree.

In an embodiment, the difference between the solubility parameter of the solvent mutual solution and the solubility parameter of the solvent is greater than or equal to 0 and less than or equal to 2, for example: 0.1, 0.3, 0.5, 0.7, 0.9, 1.1, 1.3, 1.5 , 1.7, 1.9 or 2 to improve the dissolution effect. Preferably, the difference between the solubility parameter of the solvent mutual solution and the solubility parameter of the solvent is greater than or equal to 0 and less than or equal to 0.5.

The above-mentioned solubility parameter is a physical constant that measures the solubility of liquid materials, and its physical meaning is the square root of the cohesive energy density of the material.

In an embodiment, the plastic is poorly soluble in the solvent solution. Preferably, the plastic is substantially insoluble in the solvent solution. More preferably, the plastic is insoluble in the solvent solution.

The above-mentioned "hardly soluble" means that the plastic is essentially insoluble in the solvent solution at a temperature of 80 ^○ C to 140 ^○ C and a time of 40 minutes.

In one embodiment, based on the total volume of the solvent and the solvent mutual solution, the solvent is 45 volume percent to 60 volume percent, for example: 45 volume percent, 48 volume percent, 51 volume percent, 53 volume percent, 56 volume %, 59 volume % or 60 volume %; and the solvent mutual solution is 40 volume % to 55 volume %, for example: 40 volume %, 41 volume %, 44 volume %, 47 volume %, 49 volume %, 52 volume Percent or 55 volume percent.

Preferably, based on the total volume of the solvent and the solvent mutual solution, the solvent is 48 volume percent to 52 volume percent, and the solvent mutual solution is 48 volume percent to 52 volume percent. More preferably, based on the total volume of the solvent and the solvent mutual solution, the solvent is 50 volume percent, and the solvent mutual solution is 50 volume percent.

In one embodiment, the ratio of the volume of the solvent to the volume of the solvent solution is 0.8 to 1.5; for example: 0.8, 1.0, 1.2, 1.4 or 1.5. For example, when the solvent is 100 ml and the solvent mutual solution is 100 ml, the ratio of the volume of the solvent to the volume of the solvent mutual solution is 1; or when the solvent is 120 ml and the solvent mutual solution is 100 ml, the ratio of the volume of the solvent to the solvent mutual solution is 1. The solution is 100 ml, then the ratio of the volume of the solvent to the volume of the solvent solution is 1.2.

In one implementation, before or during the preparation step, a classification step is further included: preparing classification solutions with different specific gravity to float out plastic-containing materials with different specific gravity.

Preferably, the above classification step is to float out plastic-containing materials with different specific gravity ranges in order from low to high specific gravity.

In one embodiment, the specific gravity is 0.8 to 1.6, such as 0.8, 1.0, 1.2, 1.4 or 1.6. For example, flotation is carried out in the order of specific gravity of 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 and 1.6. Preferably, the specific gravity is 0.8 to 1.0. More preferably, the proportion is 0.8 to 0.9. Through flotation, the present invention can effectively screen out non-polypropylene materials to improve polypropylene recycling efficiency.

In one embodiment, the plastic-containing material is in the form of granules.

Preferably, the average diameter of the plastic material is greater than 0 mm and less than or equal to 5 mm, such as 1 mm, 2 mm, 3 mm, 4 mm or 5 mm.

The heating temperature of the heating step of the present invention is 80 ^○ C to 140 ^○ C, for example: 80 ^○ C, 100 ^○ C, 120 ^○ C or 140 ^○ C. Preferably, the heating temperature of the heating step is 130 ^○ C to 140 ^○ C, such as: 130 ^○ C, 133 ^○ C, 136 ^○ C, 139 ^○ C or 140 ^○ C.

In one embodiment, the stirring speed in the heating step is 15 rpm to 40 rpm, such as: 15 rpm, 20 rpm, 25 rpm, 30 rpm, 35 rpm or 40 rpm. The present invention can maintain the plastic material continuously suspended in the solvent through stirring, thereby improving the dissolution efficiency and recovery rate.

In one embodiment, the heating step lasts from 15 minutes to 60 minutes, such as 15 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes or 60 minutes.

In one embodiment, based on 100 ml of the solvent, the weight of the plastic material is greater than 0 grams and less than or equal to 2.2 grams, for example: 0.05 grams, 0.1 grams, 0.15 grams, 0.2 grams, 0.25 grams, 0.3g, 0.35g, 0.4g, 0.5g, 0.6g, 0.7g, 0.8g, 0.9g, 1.0g, 1.1g, 1.2g, 1.3g, 1.4g, 1.5g, 1.6g, 1.7g, 1.8g , 1.9g, 2.0g, 2.1g or 2.2g. Preferably, based on 100 ml of the solvent, the weight of the plastic material is 1.4 to 1.6 grams. According to the present invention, the ratio range between the volume of the solvent and the weight of the plastic-containing material not only makes the first mixture easy to stir, but also helps to increase the plastic recovery rate.

In an embodiment, based on the total volume of the solvent and the solvent solution being 100 ml, the weight of the plastic material is greater than 0 grams and less than or equal to 2.2 grams, for example: 0.05 grams, 0.1 grams, 0.15 Gram, 0.2g, 0.25g, 0.3g, 0.35g, 0.4g, 0.5g, 0.6g, 0.7g, 0.8g, 0.9g, 1.0g, 1.1g, 1.2g, 1.3g, 1.4g, 1.5g, 1.6g, 1.7g, 1.8g, 1.9g, 2.0g, 2.1g or 2.2g. Preferably, based on the total volume of the solvent and the solvent solution being 100 ml, the weight of the plastic material is 1.4 to 1.6 grams. According to the present invention, the ratio range between the total volume of the solvent and the solvent mutual solution and the weight of the plastic-containing material not only makes the first mixture easy to stir, but also helps to increase the plastic recovery rate.

In one embodiment, the (three) heating step includes: (three): heating and stirring the first mixture at a temperature of 80 ^○ C to 140 ^○ C to dissolve the plastic in the solvent to obtain a second mixture; and (3/2): filter the second mixture with a filter to obtain a solution. The present invention can thereby remove impurities that are insoluble in the solvent to improve the purity of the recovered product.

In one embodiment, the step (three-two) further includes a precipitation step, that is, after obtaining the second mixture, the second mixture is allowed to stand to obtain a rested second mixture; wherein, the second mixture is allowed to stand still. The temperature of the resting second mixture is lower than that of the second mixture and contains a supernatant liquid and a precipitate. The impurities in the supernatant liquid are then filtered with a filter to obtain the dissolved liquid. In other words, the present invention can remove impurities by removing undissolved components and suspended solids through a precipitation step, that is, letting the second mixture stand without heating, and using a filter.

Preferably, in the precipitation step, the second mixture is allowed to stand for 2 to 3 hours. In the present invention, by allowing the second mixture to stand at room temperature, and then filtering the supernatant through a filter screen after obvious precipitation occurs in the stood second mixture, compared to directly filtering the second mixture , which can shorten the time required for filtration and reduce the amount of impurities contained in the solution.

In summary, the plastic recycling method of the present invention has a high plastic recovery rate, and both the solvent and the solvent solution can be recycled and reused, which not only reduces costs, but also avoids environmental problems.

Several operating modes are provided below to illustrate the implementation of the present invention; those skilled in the art can easily understand the advantages and effects achieved by the present invention through the content of this description, and can perform various operations without departing from the spirit of the present invention. Modifications and changes to implement or apply the contents of the present invention.

As shown in Figure 1, the plastic recycling method of the present invention first proceeds to step S1: preparation step: prepare a plastic-containing material, the plastic-containing material includes a plastic, and the plastic includes polypropylene. Specifically, the plastic-containing material is a powder obtained by crushing and sieving industrial waste containing polypropylene. For example, it is sieved through a 10-mesh screen to obtain a plastic-containing material with a diameter of less than 2 mm. Plastic material particles.

Next, perform S2: mixing step: mix the plastic material and a solvent to obtain a first mixture, wherein the plastic can be dissolved in the solvent. Specifically, xylene is selected as the solvent, and the plastic material and xylene are mixed to obtain a first mixture.

After that, perform S3: heating step: heat and stir the first mixture at a temperature of 80 ^○ C to 140 ^○ C, and dissolve the plastic in the solvent to obtain a solution. Specifically, the heating temperature of the heating step is 140 ^° C, the stirring speed is 20 rpm to 30 rpm, and the time is 20 minutes to 40 minutes.

Finally, proceed to S4: separation step: place the solution into a negative pressure environment to obtain the plastic. Specifically, the dissolved liquid is moved to a vacuum concentration device and then sealed. A negative pressure is formed by pumping air to boil the dissolved liquid and separate the xylene to obtain flake or granular polypropylene.

Please refer to Figures 1 and 2. When the plastic-containing material is industrial waste containing polypropylene, since it contains components insoluble in solvents, the S3 heating step includes: S3-1: heating and stirring the first mixture, The temperature is 80 ^○ C to 140 ^○ C, and the plastic is dissolved in the solvent to obtain a second mixture; and S3-2: filter the second mixture with a filter to obtain a solution. Specifically, a strainer is used to remove undissolved solids to remove impurities. In addition, before using a filter to remove undissolved solids, the second mixture can be allowed to stand at room temperature. After obvious precipitation occurs in the stood second mixture, the supernatant can be filtered. .

Test Example 1 and Test Example 2: Solvent Recovery Condition Test

The separation step of step (4) of the present invention is to place the dissolved liquid into a negative pressure environment, so first test the pressure required in the negative pressure environment and the corresponding recovery time. The operation is as follows: select xylene as the solvent, and add 200 ml of After the xylene solution is poured into the sample bottle, it is then placed in a negative pressure environment, that is, a vacuum concentrator, to simulate the separation step of step (4) of the present invention; wherein, the sample bottles of Test Example 1 and Test Example 2 are in Water bath heating is performed in the vacuum concentrator. The temperature is set to 80 ^○ C. The rotation speed of the sample bottle is set to 20 rpm. The pressure is measured according to the pressure gauge equipped with the air pump, and it is recorded that the water bath heating starts from room temperature. The time required for 200 ml of xylene solution to completely evaporate. The results are shown in Table 1. In addition, the pump function is to pump air, and it is difficult to accurately control the negative pressure environment pressure. Therefore, only 20 mbar is used as a benchmark to test the two groups of negative pressure environment pressures.

Table 1: Negative pressure environment pressure, evaporation time and solvent recovery rate used in Test Example 1 and Test Example 2 Group Negative pressure environment pressure evaporation time Solvent recovery rate Test example 1 Greater than 20 mbar to 80 mbar 30 minutes ＞98% Test example 2 0 mbar to 20 mbar 15 minutes ＞98%

It can be seen from Table 1 that the negative pressure environment pressure of Test Example 1 is greater than 20 mbar to 80 mbar, which is about 20% to 80% of one atmosphere (1.013 bar), and the required evaporation time is about 30 minutes; Test Example The negative pressure environment pressure of 2 is 0 mbar to 20 mbar, which is about 0% to 20% of one atmosphere (1.013 bar). The required evaporation time is about 15 minutes, and the solvents in Test Examples 1 and 2 The recovery rates are all greater than 98%. It can be seen that reducing the negative pressure environment pressure can significantly reduce the time required for the separation step of step (4) of the present invention without affecting the solvent recovery rate, thereby improving efficiency.

Example 1 To the embodiment 7

The plastic-containing materials, solvents and solvent mutual solutions used in Examples 1 to 7 are shown in Table 2. First, the plastic-containing material is crushed with a crushing device and sieved through a 10-mesh screen to obtain plastic-containing material particles with a diameter of less than 2 mm. After adding 3 grams of plastic-containing material particles to a solvent (or a mixed solution containing a solvent and a mutual solution of the solvent), a first mixture is obtained. After that, the first mixture is heated to 140 ^○ C by an electric furnace, and during the heating process, the first mixture is stirred at a rotation speed of 20 to 30 rpm, and maintained at 140 ^○ C for 20 to 40 minutes to continue stirring. The plastic material particles are dissolved and a solution is obtained.

Move the dissolved solution to the vacuum concentration device, insulate the dissolved solution in a 90 ^○ C heated water bath, and turn on the water flow switch of the condenser tube. After confirming that the vacuum concentration system is sealed, open the exhaust pump to reduce the pressure in the system to 0 mbar to 20 mbar. After the solution begins to boil or evaporate, close the exhaust pump and use the condenser tube to condense. The vapor of the solvent (and solvent mutual solution) is used to recover the solvent (and solvent mutual solution) while keeping the pressure within the system from rising. Finally, after the solvent (and solvent mutual solution) is completely evaporated, solid polypropylene in the form of flakes or granules is obtained, which is washed with water to remove the residual xylene smell and then air-dried to obtain the recovered polypropylene, which is then weighed. And check the appearance, the results are shown in Table 3. The above-mentioned mixed solution containing a solvent and a solvent-to-solvent solution can be recycled and directly reused without separation; or the solvent and the solvent-to-solvent solution can be separated by utilizing the different boiling point characteristics of the solvent and the solvent-to-solvent solution.

The above-mentioned recovered solvent (and solvent mutual solution) is in a clear state and can be reused. In addition, Examples 5 to 7 of the present invention use industrial waste containing polypropylene, so they contain components insoluble in solvents. Therefore, between the heating step and the separation step, an additional filtration step is performed: with 500 mesh Stainless steel mesh filters to remove solids above 25 microns. In addition, before filtering the solution, let the solution stand at room temperature for 2.5 hours. After it cools down and obvious precipitation appears, take the supernatant and filter it. Finally, the polypropylene-containing industrial waste used in Examples 5 to 7 was first confirmed to contain polypropylene by optical methods before being dissolved, and strong oxidants were used to remove residual organic matter and impurities.

Table 2: Plastic-containing materials, solvents and solvent mutual solutions used in Examples 1 to 7 Group plastic material Solvent Solvent mutual solution Kind Volume (ml) Kind Volume (ml) Example 1 Commercially available polypropylene xylene 200 without 0 Example 2 Commercially available polypropylene xylene 100 Tetrahydrofuran 100 Example 3 Commercially available polypropylene xylene 100 cyclohexanone 100 Example 4 Commercially available polypropylene xylene 100 acetone 100 Example 5 Industrial waste containing polypropylene xylene 200 without 0 Example 6 Industrial waste containing polypropylene xylene 200 without 0 Example 7 Industrial waste containing polypropylene xylene 200 without 0

Table 3: Polypropylene recycling weight and appearance from Example 1 to Example 7 Group Polypropylene Polypropylene appearance Solvent recovery rate Recycling weight Recovery rate Example 1 2.81 grams 93.7% Except for the granular or flake shape, the other appearance characteristics are no different from commercially available polypropylene. ＞90% Example 2 2.73 grams 91% Except for the granular or flake shape, the other appearance characteristics are no different from commercially available polypropylene. ＞90% Example 3 2.78 grams 92.7% Except for the granular or flake shape, the other appearance characteristics are no different from commercially available polypropylene. ＞95% Example 4 2.77 grams 92.3% Except for the granular or flake shape, the other appearance characteristics are no different from commercially available polypropylene. ＞95% Example 5 2.01 grams without The shape is granular or flaky, and the color is darker than commercially available polypropylene. without Example 6 2.05 grams without The shape is granular or flaky, and the color is darker than commercially available polypropylene. without Example 7 2.02 grams without The shape is granular or flaky, and the color is darker than commercially available polypropylene. without

From the comparison of Example 1 to Example 4, it can be seen that the polypropylene recovery weight obtained by using xylene as the solvent is the highest, and is as high as 93.7% (the calculation formula is 2.81/3*100%), and when the solvent mutual solution is used instead When a portion of the solvent is used, the recovered weight of polypropylene is only slightly reduced, indicating that the solvent-to-solvent solution can indeed replace the solvent and maintain a high polypropylene recovery rate, even though polypropylene is insoluble in the solvent-to-solvent solution. Secondly, the solvent recovery rates of Examples 1 to 4 are all higher than 90%, even higher than 95%, and the loss is extremely low; in addition, the FTIR test results of the recovered materials obtained from Examples 1 to 4 are consistent with those of commercially available solvents. The signals for polypropylene are consistent, indicating that the present invention can indeed effectively recycle polypropylene. Finally, since the polypropylene content of the polypropylene-containing industrial wastes from Examples 5 to 7 was unknown, the test was performed three times in the same manner. Based on the color of the recycled polypropylene obtained in Examples 5 to 7, which are all darker than commercially available polypropylene, it is determined that they are not pure polypropylene and may contain other components that are also soluble in xylene.

Example 8 To the embodiment 11

The plastic-containing materials, solvents and solvent mutual solutions used in Examples 8 to 11 are shown in Table 4; among them, the plastic-containing material particles in each group are all commercially available polypropylene, and except for (1) commercially available polypropylene The addition amount is 0.8 grams; (2) the solvent in each group is 100 ml of xylene; and (3) the volume ratio of the solvent in each group and the solvent solution is 1:1, the other experimental methods are the same as in Example 1 to Example 7.

Table 4: Solvents and solvent mutual solutions used in Examples 8 to 11 Group Solvent mutual solution Polypropylene recycling rate Solvent and solvent-to-solvent recovery rates Example 7 Propylene glycol methyl ether acetate 95% 85% Example 8 Butyl acetate 96% 75% Example 9 Isoamyl acetate 94% 85% Example 10 cyclohexanone 95% 90%

It can be seen from Table 4 that when the solvent mutual solution uses propylene glycol methyl ether acetate, butyl acetate, isopentyl acetate and cyclohexanone, the polypropylene recovery rates are all higher than 94%, and in Example 8 using butyl acetate The recovery rate of polypropylene is the best, reaching 96%, but the recovery rate of its solvent and solvent-to-solvent solution is the lowest, only 75%. In addition, the solvent mutual solutions of Example 3 and Example 10 both use cyclohexanone, and the volume ratio with xylene is 1:1. Based on the polypropylene recovery rate of Example 3, it is 92.7%, which is the same as that of Example 10. 95% is similar, so when the weight percentage (W/V) of polypropylene is close to 1.5 g/100 ml, the recycling efficiency is higher.

In summary, it can be seen that the plastic recycling method of the present invention does have a high plastic recovery rate, and both the solvent and the solvent-to-solvent solution can be recycled and reused, which not only reduces costs, but also avoids environmental problems.

S1: Steps S2: Step S3: Steps S3-1: Steps S3-2: Steps S4: Steps

Figures 1 and 2 are flow charts of the plastic recycling method of the present invention.

without

S1: Steps

S2: Step

S3: Steps

S4: Steps

Claims (10)

A plastic recycling method includes: (1) Preparation step: Prepare a plastic material, the plastic material contains a plastic, and the plastic contains polypropylene (PP); (2) Mixing step: Mix the plastic material and a solvent to obtain a first mixture, wherein the plastic can be dissolved in the solvent; (3) Heating step: heating and stirring the first mixture at a temperature of 80 ^○ C to 140 ^○ C to make the plastic soluble in the solvent, To obtain a dissolving solution; and (4) separation step: placing the dissolving solution into a negative pressure environment to obtain the plastic. The plastic recycling method as described in claim 1, wherein the separation step further includes: insulating the dissolving liquid at a temperature of 70 ^○ C to 100 ^○ C. The plastic recycling method of claim 1, wherein the solvent contains any one of aromatic hydrocarbons, ketones, ethers, cycloalkanes, esters, or a combination thereof. The plastic recycling method as described in claim 3, wherein the aromatic hydrocarbons include any one of benzole, toluene, xylene, tetralin, decalin or their combinations combination. The plastic recycling method according to claim 1, wherein in the mixing step, a solvent mutual solution is further added, and the solvent mutual solution contains any one of ether, ketone, lipid or a combination thereof. The plastic recycling method of claim 5, wherein the ether includes tetrahydrofuran; the ketone includes cyclohexanone, acetone or a combination thereof; and the ester includes any one of propylene glycol methyl ether acetate, butyl acetate, and isoamyl acetate. or combination thereof. The plastic recycling method as described in claim 5, wherein based on the total volume of the solvent and the solvent mutual solution, the solvent is 45 volume percent to 60 volume percent, and the solvent mutual solution is 40 volume percent to 55 volume percent. . The plastic recycling method as described in claim 1, wherein the plastic-containing material is in the form of granules, and the average diameter of the plastic-containing material is greater than 0 mm and less than or equal to 5 mm, and the stirring speed in the heating step is 15 rpm to 40 rpm. rpm, the time is from 15 minutes to 60 minutes, and the pressure of the negative pressure environment is greater than or equal to 0 mbar and less than or equal to 90 mbar. The plastic recycling method as described in claim 1, wherein based on 100 ml of the solvent, the weight of the plastic-containing material is greater than 0 grams and less than or equal to 2.2 grams. The plastic recycling method as described in claim 5, wherein the weight of the plastic-containing material is greater than 0 grams and less than or equal to 2.2 grams based on the total volume of the solvent and the solvent mutual solution being 100 ml.

Images