JP7419716B2 - Manufacturing method of recycled polymer material - Google Patents

Description

The present invention relates to a method for recycling polymeric materials in industrial waste that have been discarded in large quantities in recent years, wastes generally called plastics. This is a manufacturing method for obtaining a recycled layer polymer material from a polymer material including polyimide, polyamide resin (nylon), polysaccharide, starch, phenol resin, urea resin, melamine resin, polycarbonate resin, and unsaturated polyester resin. .
The present invention is a method for obtaining recycled polymeric materials from preferably insoluble and infusible polymeric materials, and such polymeric waste can be recovered and processed and used for heat-resistant electrical parts, automobile parts, etc. The present invention relates to a method that can be recycled as polymer powder.

Condensation polymer materials represented by polyimide and unsaturated polyester resins have high mechanical strength and heat resistance, but they also have excellent chemical resistance, are insoluble in solvents, and are sometimes non-thermoplastic. Many cannot be melted and reused like thermoplastics such as polyethylene, polypropylene, and polystyrene.
Therefore, in many cases, industrial waste containing insoluble and infusible polymer materials such as condensation polymer materials is difficult to recycle or recycle, and unfortunately, most of it is currently landfilled. Disposed of or incinerated.
In order to recycle and effectively utilize waste containing insoluble and infusible polymer materials such as condensation polymers, which are discarded in large quantities as some industrial wastes, mechanically pulverize to obtain powder. However, it is important that it contains metal impurities due to machine wear and that it can only obtain powder with an average particle size on the order of several tens of micrometers, so it is limited as a molding material when reused. This has become a major issue.
To solve this problem, chemical recycling means and techniques for chemically decomposing polyimide, for example, have been proposed.

For example, using an autoclave or the like, a method in which polyimide is made to coexist with water or alcohol and decomposed into low molecular weight substances under high temperature and high pressure conditions of 110° C. or higher and 1 MPa or higher (see Patent Document 1), a method in which a member having a polyimide resin and water A method of decomposing polymer-containing solids such as polyimide at temperatures above 200°C and below 400°C and above the saturated water vapor pressure of water at that temperature in an autoclave with a solubility parameter of 18 (see Patent Document 2). (MJ/m ³ ) A method of decomposing the polymer solid by contacting it with a solvent containing a solvent having ^1/2 or more at a temperature of 200° C. or higher (see Patent Document 3), a polymer decomposition material A method of hydrolyzing polyimide by holding it at a high temperature of 200 to 700°C and a high pressure of 2 to 100 MPa using a highly polar solvent or supercritical water or subcritical water (patent document) 4) have been proposed. These proposed methods are used to remove polyimide from metal components in order to decompose it to an extremely low molecular weight, so the resulting polyimide component cannot be reused as it is as a molded product, and it requires high temperature and high pressure conditions. Therefore, for industrial use, special equipment such as large-capacity high-temperature, high-pressure reaction vessels is required, which requires high capital investment, requires maintenance to maintain safety, and requires advanced operating technology, making it difficult to put into practical use. There are many top issues.

In addition, the method for alkaline hydrolysis of polyimide to produce low molecular weight products and the recovery of these low molecular weight products eliminates the need for special equipment such as high-temperature, high-pressure resistant reaction vessels, and the use of solvents, and the use of chemicals used for decomposition and neutralization. A method has been proposed in which a low-molecular-weight material with a small average particle size is produced in a state with few impurities caused by oxidation, and the low-molecular-weight material is recovered as a powder and used as a molding material, etc. (see, for example, Patent Documents 5 and 6). However, there is no clear description regarding the heat resistance of the polyimide powder obtained using these methods, and it is highly likely that the heat resistance originally possessed by polyimide is greatly impaired. In addition, in these proposed methods, since the chemicals used for decomposition and neutralization are used in one way, the amount of acids and alkalis used is enormous, resulting in an extremely large chemical cost burden. , there are practical issues.

Japanese Patent Application Publication No. 2001-163973 JP2002-284924A Japanese Patent Application Publication No. 2002-256104 Japanese Patent Application Publication No. 10-287766 Japanese Patent Application Publication No. 2006-124530 Patent No. 5695675

Above, we have provided an overview of the recycling methods for waste mainly containing condensation polymers, using polyimide as a representative example, but all of them require special equipment such as high-temperature, high-pressure reaction vessels, advanced operating techniques, and are difficult to obtain. There were also many problems, such as the quality of recycled products that could not always be guaranteed.
The present invention minimizes the amount of chemicals required for decomposition and neutralization without requiring special equipment such as large-capacity high-temperature, high-pressure reaction vessels, or advanced operating techniques, and can be obtained by recovering the chemicals. It is an object of the present invention to provide a method for producing a recycled polymer material, which can turn the recycled polymer material into powder with a suitable average particle size that can be used as a molding material.

That is, the present invention has the following configuration.
[1] a) A first step of immersing the recycled polymer material, which is solid at room temperature, in a first treatment liquid with an alkali ion concentration in the range of 0.5 to 20.0 mol/L;
b) At the stage where the hydrolysis of the recycled polymeric material has progressed to a critical decomposition state, the step of removing the recycled polymeric material in a critical decomposition state from the first treatment liquid;
c) The recovered polymer material in a critical decomposition state is immersed in a second treatment liquid having an alkali ion concentration of 0.0 to 0.5 mol/L and dissolved to obtain a solution of the recycled polymer material. process,
d) neutralizing the solution with an acid, precipitating the dissolved substance, and recovering it as a powder;
A method for producing a recycled polymer material having at least the following.
[2] The method for producing a recycled polymer material according to claim 1, wherein the recycled polymer material is a condensation polymer.
[3] The method for producing a recycled polymeric material according to [1] or [2], wherein the recycled polymeric material is a polymeric material having an imide bond in its main chain.
[4] The method for producing a recycled polymeric material according to [1] or [2], wherein the recycled polymeric material is a polymeric material having an ester bond in its main chain.
[5] The method for producing a recycled polymeric material according to [1] or [2], wherein the recycled polymeric material is a polymeric material having a carbonate bond in its main chain.
[6] The method for producing a recycled polymeric material according to any one of [1] to [5], wherein the second treatment liquid is a weak electrolyte aqueous solution having a pH of 6 to 9.
[7] The polymer material having an imide bond in the main chain is a condensation product of an aromatic tetracarboxylic acid anhydride and an aromatic diamine having a benzoxazole structure [3] or [6] ] The method for producing a recycled polymer material according to.

Further, the present invention preferably includes the following configuration.
[8] The method for producing a recycled polymeric material according to any one of [1] to [7], wherein the specific surface area of the recycled polymeric material is 100 square cm/g or more.
[9] The method for producing a recycled polymer material according to any one of [1] to [8], wherein the recycled polymer material is a crushed film piece having a major axis of 10 mm or less.
[10] The regeneration height according to any one of [1] to [9], wherein the processing temperature with the second processing liquid is 5° C. or more higher than the processing temperature with the first processing liquid. Method of manufacturing molecular materials.

The present invention includes a) a first step of immersing the recycled polymeric material, which is solid at room temperature, in a first treatment solution with an alkali ion concentration in the range of 0.5 to 20.0 mol/L, and b) hydrolysis. c) removing the recycled polymeric material from the first treatment liquid at the stage where it has reached a critical decomposition state; According to the method for producing a recycled polymeric material, which includes at least the step of dissolving in a second treatment liquid to obtain a solution, as explained below, the recycled polymeric material is hydrolyzed into a low molecular weight substance and this The means for recovering low molecular weight substances does not require special equipment such as high-temperature, high-pressure resistant reaction vessels or solvents in conventional technology, and the first treatment liquid with a high alkali ion concentration can be repeatedly used multiple times. Therefore, the amount of chemicals used for decomposition and neutralization can be significantly reduced.
and d) recovering recycled polymer powder having an average particle size and heat resistance suitable as a molding material through a step of neutralizing the solution with an acid, precipitating the dissolved material, and recovering it as a powder. I can do it.
The present invention is preferably applicable to all condensation polymer materials, particularly polyimide and polyamide. It can be preferably applied to polyester and polycarbonate.

The polymer materials targeted for recycling in the present invention are mainly condensation polymer materials such as saturated polyester, polyimide, polyamide resin (nylon), polysaccharides, starches, phenolic resins, urea resins, and melamine resins. , epoxy resin, polycarbonate resin, unsaturated polyester resin and the like.
It is preferable to use these recycled polymer materials in a crushed state during processing. The crushed state is preferably crushed so that the specific surface area is 100 square cm/g or more.
Further, in the present invention, it is preferable that the polymeric material to be recycled is in the form of a crushed film piece with a major axis of 10 mm or less, or a cut thread shape with a major axis of 10 mm or less. If the specific surface area is too small, the amount of alkali carried from the first treatment liquid to the second treatment liquid will be reduced, resulting in a decrease in treatment efficiency.

As the recycled polymer material of the present invention, it is particularly preferable to apply the present invention to polyimide. Polyimide is a polymer having imide bonds in its main chain.
The polyimide in the present invention has various forms, such as a film state and a state in which a metal thin film, an inorganic thin film, or a composite thereof is laminated on a film. The polyimide is not particularly limited as long as it is a polyimide obtained by polycondensation of diamines and tetracarboxylic acids, but preferably it is a polyimide obtained by the reaction of aromatic diamines and aromatic tetracarboxylic acids. More preferably, a combination of the following aromatic diamines (diamines and imide-binding diamine derivatives, hereinafter the same) and aromatic tetracarboxylic acids (acids, dianhydrides, and imide-binding acid derivatives, the same hereinafter) is used. Preferred examples include pyromellitic acid as the carboxylic acid, and diamines having a benzoxazole skeleton (structure) as the diamines.
A. A combination of aromatic diamines having a benzoxazole structure and aromatic tetracarboxylic acids.
B. A combination of aromatic diamines having a diaminodiphenyl ether skeleton and aromatic tetracarboxylic acids having a pyromellitic acid skeleton.
C. A combination of aromatic diamines having a phenylenediamine skeleton and aromatic tetracarboxylic acids having a pyromellitic acid skeleton.
D. A combination of aromatic diamines having a phenylenediamine skeleton and aromatic tetracarboxylic acids having a biphenyltetracarboxylic acid skeleton.
Moreover, a combination of one or more of the above ABCD is preferable.

Furthermore, polyester can be exemplified as a particularly preferable recycled polymer material for the present invention. Polyester is a polymer having ester bonds in its main chain. The polyester is preferably a polyester obtained as a condensate of a dicarboxylic acid component and a glycol.
Examples of dicarboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and 1,5-naphthalic acid; aromatic oxycarboxylic acids such as p-oxybenzoic acid and p-(hydroethoxy)benzoic acid; acids, aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, unsaturated aliphatic and alicyclic acids such as fumaric acid, maleic acid, itaconic acid, hexahydrophthalic acid, tetrahydrophthalic acid, etc. group dicarboxylic acids, etc.
If necessary, a small amount of tri- and tetracarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid may be included.
Glycol components include, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol. , 2,2,4-trimethyl-1,3-pentanediol, 1,4-cyclohexanedimethanol, spiroglycol, 1,4-phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, polyethylene glycol, polypropylene Examples include diols such as glycol and polytetramethylene glycol, ethylene oxide and propylene oxide adducts of bisphenol A, and ethylene oxide and propylene oxide adducts of hydrogenated bisphenol A.
If necessary, a small amount of triol and tetraol such as trimethylolethane, trimethylolpropane, glycerin, and pentaerthritol may be included.
Other examples of polyester polyols include lactone-based polyester polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone.
The present invention is preferably applied to unsaturated polyester resins that are insoluble and infusible. The unsaturated polyester resin herein includes a resin obtained by crosslinking unsaturated polyester with a vinyl polymer such as styrene.

In addition, polycarbonate resins can be mentioned as preferred recycled polymers for the present invention. A polycarbonate resin is a polymer having a carbonate bond in its main chain, and is mainly obtained as a condensate of a carbonic acid diester component and a dihydroxy component.
Carbonic diester components include, for example, diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, aromatic carbonates such as dinaphthyl carbonate and bis(diphenyl) carbonate, dimethyl carbonate, and diethyl carbonate. carbonate, aliphatic carbonates such as dibutyl carbonate and dicyclohexyl carbonate.
Examples of dihydroxy components include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane (also called bisphenol A), 2, Aromatic dihydroxy compounds such as 2-bis(4-hydroxyphenyl)butane and bis(4-hydroxyphenyl)phenylmethane, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6- Examples include aliphatic hydroxy compounds such as hexanediol and 1,2-cyclohexanedimethanol.

The first treatment in the present invention is a treatment step in which the polymeric material to be recycled is immersed in a first treatment liquid heated to a predetermined temperature until it reaches a critical decomposition state, and then taken out.
The first treatment liquid in the present invention is an aqueous solution of ammonium or alkali metal hydroxide, and is particularly limited as long as it can advance alkaline hydrolysis of the recycled polymer material to a critical decomposition state. However, examples thereof include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, ammonia, and tetramethylammonium hydroxide. The term "critical decomposition state" as used herein refers to a state when the recycled polymer material to be hydrolyzed changes from an increase in mass to a decrease in mass due to reaction.
The hydrolysis reaction progresses as water molecules break into the bonds in the main chain of the polymeric material, cutting the bonds in the main chain. However, if the progress is relatively slow, water molecules are added to the polymer material. The mass of the apparent solid portion increases due to an increase in molecular weight due to this and swelling due to further increase in hydrophilicity of the polymer material. As the hydrolysis reaction further progresses, a portion with a lower molecular weight due to the progression of main chain scission is eluted into the treatment liquid, and the mass of the apparent solid portion begins to decrease. This inflection point is referred to as a critical decomposition state in the present invention.
In order to know the time to reach the critical decomposition state, the recycled polymeric material is immersed in the first treatment liquid under predetermined conditions, and the recycled polymeric material is taken out from the treatment liquid at regular time intervals and its mass is measured. The above inflection point can be found from the time plot. From the point of view of actual work, it is preferable to adjust the pH or alkali ion concentration of the treatment liquid and the temperature of the treatment liquid so that the time required to reach the critical decomposition state is between 10 and 600 minutes. Under these conditions, it is possible to measure the time it takes to reach a critical decomposition state by measuring changes in mass every few minutes.

The alkali ion concentration of the first treatment liquid in the present invention is preferably in the range of 0.5 to 20.0 mol/L. The temperature of the first treatment liquid is preferably in the range of 50 to 100°C. When the alkali ion concentration exceeds 0.5 mol/L, the hydrolysis rate is too slow, which often causes practical problems, and when it exceeds 20.0 mol/L, the recycled polymer material is too decomposed to be practical. Not the point. If the temperature of the first treatment liquid is less than 50°C, the hydrolysis rate is too slow, which often causes practical problems, and if it exceeds 100°C, the recycled polymer material may decompose too much, and pressure may be applied. Technical issues arise, such as the need for containers. The alkali ion concentration of the first treatment liquid is preferably in the range of 1.0 to 10.0 mol/L, and the temperature of the first treatment liquid is more preferably 70 to 95°C.

The first treatment liquid of the present invention can be used repeatedly. Repeated use means that it can be used repeatedly for the recycling treatment of polymeric materials, and in the present invention, it is determined that repeated use is possible when it can be used repeatedly five or more times.

In the present invention, the bath ratio of the first treatment, that is, the mass ratio of the mass of the object to be treated and the treatment liquid, is preferably 15/100 or less, more preferably 7/100 or less, even more preferably 4/100 or less. be. If the bath ratio exceeds a predetermined range, the treatment efficiency will drop significantly and it will become difficult to repeatedly use the treatment liquid.
The lower limit of the bath ratio for the first treatment in the present invention is 0.5/100, preferably 0.2/100. If the bath ratio is lower than this range, not only the treatment efficiency will be lowered, but also the amount of alkali brought into the second treatment bath will be reduced, which may interfere with the second treatment.

The second treatment liquid in the present invention is composed of an alkaline component brought in by the recycled polymer material whose hydrolysis has reached a critical decomposition state in the first treatment liquid, and decomposition products of the recycled polymer component. There is no particular limitation as long as it dissolves the recycled polymer material whose hydrolysis has progressed to a critical decomposition state. Examples include pure water or ion-exchanged water, and weak electrolyte aqueous solutions such as buffer solutions, but pure water or ion-exchanged water is preferable.

In the second treatment of the present invention, the recycled polymer material after the first treatment is immersed in a second treatment liquid heated to a predetermined temperature for a predetermined period of time to dissolve the recycled polymer material. This is a processing step to obtain For the sake of convenience, this is a solution of the polymeric material to be recycled, but chemically, it is a solution of the polymeric material to be recycled that has become soluble in an alkaline solution as a decomposed product or an alkali-denatured product.
The alkali ion concentration of the second treatment liquid in the present invention is preferably in the range of 0.0 to 0.5 mol/L, and the pH is preferably in the range of 6 to 9. It is preferable that the melting treatment of the recycled polymeric material that has reached a critical decomposition state is carried out at a temperature of 70 to 100°C. If the pH of the second treatment liquid is less than 6, the solubility of the recycled polymeric material often decreases significantly, and if the alkali ion concentration is 0.5 mol/L or higher or the pH is 9 or higher, the recycled polymeric material It is not practical as it often results in salting out. If the melting treatment temperature is also less than 70°C, the solubility of the recycled polymer material often decreases significantly, and if it exceeds 100°C, pressure resistance and technical problems will increase. More preferably, the second treatment liquid has an alkali ion concentration of 0.0 to 0.1 mol/L, a pH of 7 to 8, and a dissolution treatment temperature of 80 to 80. The temperature is 95°C.

In the present invention, the bath ratio of the second treatment, that is, the mass ratio of the mass of the object to be treated and the treatment liquid, is preferably 15/100 or less, more preferably 7/100 or less, even more preferably 4/100 or less. be. If the bath ratio exceeds a predetermined range, the treatment efficiency will drop significantly and it will become difficult to repeatedly use the treatment liquid.
The lower limit of the bath ratio for the second treatment in the present invention is 0.5/100, preferably 0.2/100. If the bath ratio is lower than this range, not only the treatment efficiency will be lowered, but also the amount of alkali brought into the second treatment bath will be reduced, which may interfere with the second treatment.

In the present invention, recovering the recycled polymer material dissolved in the second treatment liquid as a powder can be easily carried out by filtration of undissolved materials and precipitation separation by adding an acidic aqueous solution. Further, alkali metals remaining in the recovered material can be sufficiently removed by washing the recovered material with water.

When processing a film-shaped recycled polymer material in the present invention, it is preferable to process the film-shaped recycled polymer material by cutting it into pieces, and more preferably, the average size of the pieces is 10 mm or less on the maximum side, and Preferably, it is finely divided into pieces of 7 mm or less, more preferably 4 mm or less. If the size of the pieces is too large, stirring, flow, and transportation within the processing equipment may be hindered.
The amount of the film-shaped recycled polymer material to be processed in the present invention is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, based on the treatment liquid. It is preferable that the amount is not less than 1% by mass and not more than 5% by mass. If the processing amount is less than this range, the processing efficiency will be poor, and if the processing amount exceeds this range, the fluidity during processing will be poor and processing unevenness will increase, and the first processing liquid will be extremely contaminated and difficult to recycle. It may become.
The process of the present invention includes (1) using an open reaction tank to heat and stir the treatment liquid under normal pressure, and in some cases refluxing; (2) slowly moving the treatment liquid into a high-temperature treatment bath using a belt conveyor, etc. Examples of methods of distribution can be given. The former is preferred from the viewpoint of reaction efficiency and treatment unevenness, but the latter is preferred from the viewpoint of productivity, and (1) and (2) may be appropriately selected depending on the practical scale.

The present invention will be specifically explained with reference to the following examples, but the present invention is not limited to the following examples. In addition, the evaluation method of each characteristic in the following examples is as follows.

[Thermal decomposition temperature]
Using a dried polymer powder as a sample, thermogravimetric analysis (TGA) was performed under the following conditions, and the temperature at which the mass of the sample decreased by 5% was regarded as the thermal decomposition temperature.
Device name: TGA-Q50 manufactured by TA Instruments
Bread: Platinum bread (non-airtight)
Sample mass: 10mg
Heating start temperature: room temperature Heating end temperature: 800℃
Temperature increase rate: 10℃/min
Atmosphere: Nitrogen

[Imidization rate]
The imidization rate of the polyimide powder was evaluated according to the following IR (ATR) measurement procedure.
Collect 2 mg of the polyimide powder to be measured, place it in close contact with the ATR crystal, set it in an IR measuring device, measure the absorbance at the specific wavelength below, and calculate the imidization rate ( IMx) was obtained.
IMx = λ1778/λ1478...(1)
λ1778 is the absorbance near the imide specific wavelength of 1778 cm ⁻¹ , and λ1478 is the absorbance near the aromatic ring specific wavelength 1478 cm ⁻¹ . The IR (ATR) measurement conditions used this time are shown below.
<IR measurement conditions>
Name of equipment used: JASCO Corporation FT/IR6100
Resolution: 4cm ^-1
Measurement wave number range: 600 to 4000 cm ^-1
Sensitivity; 1
Detection time: 1.05sec

<Example 1>
As the recycled polymer material (polyimide), a crushed product obtained by processing a 25 μm thick polyimide film “Xenomax” (registered trademark) manufactured by Toyobo Co., Ltd. using a crusher so that the major axis was 5 mm or less was used. The specific surface area of the crushed product estimated from the mass per unit volume of the film is 530 square meters/g.

A 4.0 mol/L aqueous sodium hydroxide solution was used as the first treatment liquid. The pH of the first treatment liquid was 14. As a preliminary test, we immersed a certain amount of recycled polymer material in the first treatment solution at 70°C and measured the change in mass of the solid content in 5 minute increments. The time required to reach a critical decomposition state was 75 minutes.

1 part by mass of polyimide as a recycled polymer material was immersed in 100 parts by mass of the first treatment liquid, and alkaline hydrolysis was performed at a temperature of 70°C. After 75 minutes, a solid in a critical decomposition state (polyimide with advanced hydrolysis) was filtered out. The filtrate was stored separately.

100 parts by mass of ion-exchanged water at a temperature of 90° C. was prepared as the second treatment liquid.
Add 1 part by mass of the solid in a critical decomposition state (polyimide with advanced hydrolysis) taken out from the first treatment liquid to the second treatment liquid, stir for 30 minutes, and confirm that the solid is no longer visible. After confirmation, a solution of the object to be treated was obtained.

Next, the solution was neutralized by dropping 5% by mass of sulfuric acid into the solution until the pH reached 7. Upon neutralization, the dissolved substance in the solution was precipitated as a solid powder.

The precipitated solid powder was filtered out and washed with water. For washing with water, the process of putting the solid powder into 100 times the volume of water, stirring for 5 minutes at room temperature, and then filtering to take out the solid powder was repeated three times. The solid powder after washing with water was dehydrated under reduced pressure and dried at a temperature of 80° C. for 12 hours or more to obtain a solid powder with a water content of 1.0% or less.

The solid powder was heated in a heating furnace at a heating rate of 1°C/min and heated at 450°C for 7 minutes to obtain polyimide powder with an imidization rate of 85% or more as a recycled polymer material. .
The same operation was repeated five times using the same first treatment liquid. Sufficient treatment was also possible for the fifth time.

<Examples 2 to 6><Comparative Examples 1 and 2>
Recycled polymer materials were similarly obtained using the materials and conditions shown in Table 1. The obtained recycled polymer material was evaluated. The results are shown in Table 1.
In addition, polyimide 1 in Table 1 is a crushed product of Xenomax (registered trademark) 25 μm thick [manufactured by Toyobo Co., Ltd.];
Polyimide 2 is a crushed product of Kapton (registered trademark) 12.5 μm thick [manufactured by DuPont-Toray],
The polyester is a crushed product of Toyobo Ester Film (registered trademark) 50 μm thick [manufactured by Toyobo Co., Ltd.]
The polycarbonate is a crushed product of Iupilon (registered trademark) 100 μm thick [manufactured by Mitsubishi Gas Chemical Company].

As described above, according to the present invention, mainly condensation polymer materials such as saturated polyester resin, polyimide, polyamide resin (nylon), polysaccharide, starch, phenolic resin, urea resin, melamine resin, Recycled polymer materials can be efficiently obtained from preferably insoluble and infusible polymer materials containing polycarbonate resins and unsaturated polyester resins, and it is also possible to reuse the treatment liquid in the regeneration process. The recycled polymer material obtained by the present invention can be widely used, for example, as a raw material for molding, and contributes not only to the reduction of waste but also to the provision of industrially useful materials.

Claims (4)

a) A first step of immersing the regenerated polymer material, which is solid at room temperature, in a first treatment liquid with an alkali ion concentration in the range of 0.5 to 20.0 mol/L , the regenerated polymer material A first step in which the material is a polymeric material having a bond selected from the group consisting of imide bonds, ester bonds, and carbonate bonds in its main chain ;
b) At the stage where the hydrolysis of the recycled polymeric material has progressed to a critical decomposition state, the step of removing the recycled polymeric material in a critical decomposition state from the first treatment liquid;
c) The recovered polymer material in a critical decomposition state is immersed in a second treatment liquid having an alkali ion concentration of 0.0 to 0.5 mol/L and dissolved to obtain a solution of the recycled polymer material. process,
d) neutralizing the solution with an acid, precipitating the dissolved substance, and recovering it as a powder;
A method for producing a recycled polymer material having at least the following. 2. The method for producing a recycled polymeric material according to claim 1, wherein the recycled polymeric material is a condensation polymer. 3. The method for producing a recycled polymeric material according to claim 1, wherein the second treatment liquid is a weak electrolyte aqueous solution having a pH of 6 to 9. Any one of claims 1 to 3 , wherein the polymer material having an imide bond in the main chain is a condensate of an aromatic tetracarboxylic acid anhydride and an aromatic diamine having a benzoxazole structure. The method for producing the recycled polymeric material described.