Recycled polycarbonate resin and method for producing same

Abstract

Provided is a method for producing a recycled polycarbonate resin having practically sufficient color tone, weather resistance, and mechanical properties. The present invention is a method for producing a recycled polycarbonate resin in which a recycled polycarbonate resin having a Mw / Mn of 2.2 or less is obtained from a waste polycarbonate resin composition containing a polycarbonate resin having a Mw / Mn of 2.8 or more. Comprises: a step (S1) for obtaining a polycarbonate resin solution by dissolving the waste polycarbonate resin composition in a good solvent containing a dichloromethane solvent and / or a phenolic solvent; a step (S2) for precipitating the recycled polycarbonate resin by mixing the polycarbonate resin solution with a poor solvent, the poor solvent including at least one of a ketone-based solvent, an alcohol, a saturated hydrocarbon-based solvent, and water; and a step (S3) for recovering the precipitated recycled polycarbonate resin.

Description

Technical Field

[0001] The present invention relates to a recycled polycarbonate resin and a method for manufacturing the same. Background Art

[0002] Polycarbonate resin is a resin having excellent mechanical properties such as heat resistance and impact resistance, excellent dimensional stability, and excellent transparency. Polycarbonate resin compositions containing polycarbonate resin are used for various purposes.

[0003] For sustainable development, it is important to recycle polycarbonate resin to recycle resources. As methods for recycling polycarbonate resin, there are roughly three methods: material recycling for regenerating into a material for polycarbonate resin, chemical recycling for regenerating into bisphenol which is a raw material for polycarbonate resin, and thermal recycling for use as energy. Patent Document 1 discloses the decomposition of polycarbonate resin to bisphenol A as a raw material. In addition, Patent Documents 2 and 3 disclose a method of dissolving polycarbonate resin in a solvent, removing insoluble substances, and then precipitating the polycarbonate resin by adding an organic solvent.

[0004] However, the polycarbonate resin contained in the waste polycarbonate resin composition may be deteriorated due to use or ultraviolet rays, resulting in a decrease in hue and mechanical properties. In addition, the polycarbonate resin composition mostly contains additives, inorganic substances, and other polymers in addition to the polycarbonate resin, and it is difficult to separate them. Therefore, the recycling use of waste polycarbonate resin compositions is limited and mostly disposable.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-75133

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 11-152371

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2004-182746 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] The method described in Patent Document 1 relates to chemical recycling for decomposing polycarbonate resin to raw material bisphenol, and the load in decomposition and purification is larger than that of material recycling. The methods described in Patent Documents 2 and 3 can be said to be simple methods compared with the method of decomposing polycarbonate resin to raw material bisphenol, but almost no mention is made of the physical properties of the recycled polycarbonate resin, and sometimes the practicality is insufficient.

[0012] Under such circumstances, a recycled polycarbonate resin is required to have a hue, weather resistance, and mechanical properties that are not problematic in practical use. The present invention has been completed in view of such circumstances, and an object thereof is to provide a recycled polycarbonate resin having practically sufficient hue, weather resistance, and mechanical properties and a method for producing the same.

[0013] Means for Solving the Problems

[0014] The inventors of the present invention repeatedly conducted in-depth studies to solve the above problems, and as a result, found that the following invention meets the above object, and thus completed the present invention. That is, the present invention relates to the following inventions.

[0015] <1> A method for producing a recycled polycarbonate resin, which is a method for producing a recycled polycarbonate resin from a waste polycarbonate resin composition, wherein the Mw / Mn of the polycarbonate resin contained in the waste polycarbonate resin composition is 2.8 or more, and the Mw / Mn of the recycled polycarbonate resin is 2.2 or less. Mw / Mn is the ratio of the weight average molecular weight Mw to the number average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography. The production method includes the following steps (S1) to (S3).

[0016] Step (S1): A step of dissolving the waste polycarbonate resin composition in a good solvent containing dichloromethane and / or a phenolic solvent to obtain a polycarbonate resin solution.

[0017] Step (S2): A step of precipitating the recycled polycarbonate resin by mixing the polycarbonate resin solution with one or more poor solvents selected from the group consisting of ketone solvents, alcohol solvents, saturated hydrocarbon solvents, and water.

[0018] Step (S3): A step of recovering the precipitated recycled polycarbonate resin.

[0019] <2> The method for producing a recycled polycarbonate resin according to the above <1>, wherein, before the step (S2), a step of bringing the polycarbonate resin solution into contact with one or more filter aids selected from the group consisting of diatomaceous earth, activated clay, activated carbon, and synthetic adsorbents to remove insoluble matters and obtain a solution (L) from which insoluble matters have been removed is included, and the solution (L) is used as the polycarbonate resin solution for the step (S2).

[0020] <3> The method for producing a recycled polycarbonate resin according to the above <1>, wherein, before the step (S2), a step of removing insoluble matters from the polycarbonate resin solution to obtain a solution (L) from which insoluble matters have been removed is included, and the solution (L) is used as the polycarbonate resin solution for the step (S2).

[0021] <4> The method for producing a recycled polycarbonate resin according to any one of <1> to <3> above, wherein the proportion of the polycarbonate resin contained in the waste polycarbonate resin composition is 20% by mass or more.

[0022] <5> The method for producing a recycled polycarbonate resin according to any one of <1> to <4> above, wherein the waste polycarbonate resin composition contains one or more selected from the group consisting of other resins, inorganic substances, and low-molecular organic compounds.

[0023] <6> The method for producing a recycled polycarbonate resin according to any one of <1> to <5> above, wherein the good solvent used in the step (S1) is a solvent containing dichloromethane or a solvent containing a phenolic solvent of 50% by mass or less (preferably 10% by mass or more and 50% by mass or less, more preferably 20% by mass or more and 50% by mass or less).

[0024] <7> The method for producing a recycled polycarbonate resin according to any one of <1> to <6> above, wherein the good solvent used in the step (S1) is 200% by mass or more and 5000% by mass or less (preferably 250% by mass or more and 4000% by mass or less, more preferably 350% by mass or more and 3000% by mass or less) with respect to the waste polycarbonate resin composition.

[0025] <8> The method for producing a recycled polycarbonate resin according to any one of <1> to <7> above, wherein the poor solvent used in the step (S2) is 200% by mass or more and 5000% by mass or less (preferably 250% by mass or more and 4000% by mass or less, more preferably 350% by mass or more and 3000% by mass or less) with respect to the waste polycarbonate resin composition.

[0026] <9> The method for producing a recycled polycarbonate resin according to any one of <1> to <8> above, wherein the content of terminal hydroxyl groups of the recycled polycarbonate resin is 200 to 530 mass ppm (preferably 200 to 520 mass ppm, more preferably 210 to 510 mass ppm, further preferably 210 to 500 mass ppm), and the content of the structural unit represented by the following formula (1) contained in its main chain is 200 to 1100 mass ppm (preferably 200 to 1000 mass ppm, more preferably 250 to 900 mass ppm).

[0027] [Chemical formula 1]

[0028]

[0029] (In formula (1), X is any one selected from the group consisting of a single bond, an alkylene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, a fluorenylidene group, a xanthenylidene group, a thioxanthenylidene group, -O-, -S-, -CO-, -SO- and -SO2- (preferably an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms or a fluorenylidene group, more preferably an alkylidene group having 1 to 8 carbon atoms, and further preferably propane-2,2-diyl), R 1 and R 2 are each independently any one selected from the group consisting of a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms and an aryl group having 6 to 12 carbon atoms (preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms), and n and m are each independently an integer of 0 to 3 (preferably 0 or 1).)

[0030] <10>The method for producing a recycled polycarbonate resin according to any one of the foregoing <1> to <9>, wherein the viscosity-average molecular weight of the recycled polycarbonate resin is greater than 19,000 (preferably greater than 19,000 and 33,000 or less).

[0031] <11>A recycled polycarbonate resin, which is a recycled polycarbonate resin regenerated from a waste polycarbonate resin composition, and the ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography: Mw / Mn is 2.2 or less (preferably 1.4 or more and 2.2 or less).

[0032] <12>The recycled polycarbonate resin according to the foregoing <11>, wherein the content of terminal hydroxyl groups in the recycled polycarbonate resin is 200 to 530 mass ppm (preferably 200 to 520 mass ppm, more preferably 210 to 510 mass ppm, and further preferably 210 to 500 mass ppm).

[0033] <13>The recycled polycarbonate resin according to the foregoing <11> or <12>, wherein the content of the structural unit represented by the following formula (1) contained in the main chain of the recycled polycarbonate resin is 200 to 1100 mass ppm (preferably 200 to 1000 mass ppm, more preferably 250 to 900 mass ppm).

[0034] [Chemical formula 2]

[0035]

[0036] (In formula (1), X is any one selected from the group consisting of a single bond, an alkylene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, a fluorenylidene group, a xanthenylidene group, a thioxanthenylidene group, -O-, -S-, -CO-, -SO- and -SO2- (preferably an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms or a fluorenylidene group, more preferably an alkylidene group having 1 to 8 carbon atoms, and further preferably propane-2,2-diyl), R 1 and R 2 are each independently any one selected from the group consisting of a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms and an aryl group having 6 to 12 carbon atoms (preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms), and n and m are each independently an integer of 0 to 3 (preferably 0 or 1).)

[0037] <14>The recycled polycarbonate resin according to any one of the foregoing <11> to <13>, wherein the viscosity-average molecular weight of the recycled polycarbonate resin is greater than 19,000 (preferably greater than 19,000 and 33,000 or less, more preferably 20,000 or more and 33,000 or less, and further preferably 21,000 or more and 33,000 or less).

[0038] <x1>A method for manufacturing a molded body, comprising: a step of obtaining a recycled polycarbonate resin by the method for manufacturing a recycled polycarbonate resin according to any one of <1> to <10> described above; and a step of obtaining a molded body using the recycled polycarbonate resin described above.

[0039] <y1>A molded article comprising the recycled polycarbonate resin according to any one of the foregoing <11> to <14>.

[0040] Advantages of the Invention

[0041] According to the present invention, a recycled polycarbonate resin having practically sufficient hue, weather resistance, and mechanical properties, and a method for producing the same can be provided. Detailed Description of Embodiments

[0042] Embodiments of the present invention will be described in detail below. However, the description of the constituent elements below is an example (representative example) of the embodiments of the present invention, and the present invention is not limited to the following content as long as its gist is not changed. In addition, when the expression "~" is used in this specification, it is used as an expression including numerical values or physical property values before and after it.

[0043] <Method for Producing Recycled Polycarbonate Resin>

[0044] The present invention relates to a method for producing a recycled polycarbonate resin in which a recycled polycarbonate resin is obtained from a waste polycarbonate resin composition (hereinafter sometimes referred to as "the production method of the present invention"), which includes the following steps (S1) to (S3).

[0045] Step (S1): A step of dissolving the waste polycarbonate resin composition in a good solvent containing dichloromethane and / or a phenolic solvent to obtain a polycarbonate resin solution

[0046] Step (S2): A step of precipitating the recycled polycarbonate resin by mixing the polycarbonate resin solution with one or more poor solvents selected from the group consisting of a ketone solvent, an alcohol solvent, a saturated hydrocarbon solvent, and water

[0047] Step (S3): A step of recovering the precipitated recycled polycarbonate resin

[0048] The production method of the present invention may be a production method for obtaining a recycled polycarbonate resin having an Mw / Mn of 2.2 or less from a waste polycarbonate resin composition containing a polycarbonate resin having an Mw / Mn of 2.8 or more.

[0049] Here, in the present application, "Mw / Mn" is the ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography.

[0050] The manufacturing method of the present invention is characterized in that, by using a specific good solvent and a specific poor solvent, even if a waste polycarbonate resin composition containing a polycarbonate resin with Mw / Mn of 2.8 or more (for example, Mw / Mn of 2.8 to 10, 2.9 to 5.0, etc.) is used as a recycling raw material, low-molecular-weight polycarbonate resins and the like can be removed, and thus the Mw / Mn of the recycled polycarbonate resin obtained is 2.2 or less. From the viewpoints of productivity and the like, the Mw / Mn of the generally used unused polycarbonate resin is about 2.5 to 2.9. In addition, the polycarbonate resin contained in the waste polycarbonate resin composition (hereinafter referred to as "waste polycarbonate resin") may be deteriorated due to heat, ultraviolet rays, water vapor, etc. during use. The Mw / Mn of the waste polycarbonate resin is the same as that of the unused polycarbonate resin when the degree of deterioration is small, but when the deterioration progresses, Mw / Mn increases to 2.8 or more, 2.9 or more, 3.0 or more, etc. If the manufacturing method of the present invention is used, the Mw / Mn of the obtained recycled polycarbonate resin can be made to be 2.2 or less, which is smaller than the Mw / Mn of the generally used unused polycarbonate resin.

[0051] In addition, according to the manufacturing method of the present invention, even if a raw material containing other components such as other resins and additives in addition to the polycarbonate resin is used, other components can be efficiently removed, and a recycled polycarbonate resin having a hue and the like that are not problematic in practice can be obtained.

[0052] Hereinafter, each process will be described.

[0053] [Process (S1)]

[0054] Process (S1) is a process of dissolving a waste polycarbonate resin composition in a good solvent containing dichloromethane and / or a phenolic solvent to obtain a polycarbonate resin solution.

[0055] [Waste polycarbonate resin composition]

[0056] The waste polycarbonate resin composition is a post-consumer material and / or a pre-consumer material of a polycarbonate resin composition. The polycarbonate resin composition is a composition containing a polycarbonate resin. For example, the content of the polycarbonate resin in the polycarbonate resin composition is 20 to 100% by mass, 50 to 100% by mass. As the polycarbonate resin composition, in addition to a single polycarbonate resin (PC), there can be mentioned those containing a waste polycarbonate resin composition and one or more substances selected from the group consisting of other resins, inorganic substances, and low-molecular organic compounds. As the polycarbonate resin composition containing other resins, there can be mentioned polymer alloys such as polymer blends of a polycarbonate resin and other resins, and in addition, it can contain two or more polycarbonate resins having different compositions and molecular weights.

[0057] As other resins, copolymers such as ABS resin and AS resin which are copolymers of acrylonitrile, butadiene and styrene, polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), acrylic resin (PMMA), etc. can be mentioned. Most of them contain 20% by mass or more. Relative to PC, ABS resin mostly contains about 30% by mass, and polyesters mostly contain about 50% by mass.

[0058] The waste polycarbonate resin composition may contain additives such as inorganic substances and low-molecular organic compounds. As representative examples of the inorganic substances, glass fiber (GF), carbon fiber for improving the strength of the polycarbonate resin, carbon black, titanium oxide, etc. which are pigments for coloring can be mentioned. The low-molecular organic compound is an organic compound having a molecular weight of 3000 or less. As representative examples thereof, ultraviolet absorbers, flame retardants, etc. can be mentioned. Most of them are contained in the polycarbonate resin composition in an amount of 5% by mass or more and less than 50% by mass. Especially when regenerating a polycarbonate resin composition containing glass fiber or the like by recycling of conventional materials, decomposition of the polycarbonate resin is caused by the glass fiber, resulting in a decrease in molecular weight. Therefore, it is difficult to regenerate these polycarbonate resin compositions by material recycling. Being able to suppress this situation is also a feature of the manufacturing method of the present invention.

[0059] The polycarbonate resin usually contains a repeating unit of a bisphenol unit and a carbonate unit, that is, a structural unit represented by the following formula (A). The content of the structural unit represented by the following formula (A) is usually 20 mol% or more, preferably 30 mol% or more, more preferably 40 mol% or more.

[0060] [Chemical formula 3]

[0061]

[0062] In formula (A), X is any one selected from the group consisting of a single bond, an alkylene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, a fluorenylidene group, a xanthenylidene group, a thioxanthenylidene group, -O-, -S-, -CO-, -SO- and -SO2-.

[0063] The alkylene group having 2 to 8 carbon atoms can be either substituted or unsubstituted, and can be linear or branched. As the alkylene group having 2 to 8 carbon atoms, ethane-1,2-diyl, propane-1,2-diyl, propane-1,3-diyl, butane-1,2-diyl, butane-1,4-diyl, hexane-1,2-diyl, hexane-1,6-diyl, etc. can be mentioned.

[0064] The cycloalkylene group having 5 to 15 carbon atoms can be either substituted or unsubstituted. Examples of the cycloalkylene group having 5 to 15 carbon atoms include cyclopropane-1,2-diyl, cyclohexane-1,2-diyl, and the like.

[0065] The alkylidene group having 1 to 8 carbon atoms can be either substituted or unsubstituted, and can be linear or branched. The alkylidene group having 1 to 8 carbon atoms is preferably a group represented by the following formula (1a).

[0066] [Chemical formula 4]

[0067]

[0068] R a 、R b each independently represents a hydrogen atom, an alkyl group having 1 to 7 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms, or an aryl group having 6 to 7 carbon atoms. They can be either substituted or unsubstituted. Examples include: hydrogen atom, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, n-heptyl, 2-ethylhexyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentyloxy, isopentyloxy, n-hexyloxy, n-heptyloxy, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, benzyl, phenyl, tolyl, and the like.

[0069] The cycloalkylidene group having 5 to 15 carbon atoms can be either substituted or unsubstituted. Examples of the cycloalkylidene group having 5 to 15 carbon atoms include: cyclopropane-1,1-diyl, cyclobutane-1,1-diyl, cyclopentane-1,1-diyl, cyclohexane-1,1-diyl, 3,3,5-trimethylcyclohexane-1,1-diyl, cycloheptane-1,1-diyl, cyclooctane-1,1-diyl, cyclononane-1,1-diyl, cyclodecane-1,1-diyl, cycloundecane-1,1-diyl, cyclododecane-1,1-diyl, and the like.

[0070] In formula (A), X is preferably an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, or a fluorenylidene group, more preferably an alkylidene group having 1 to 8 carbon atoms, and even more preferably propane-2,2-diyl.

[0071] In formula (A), R 1 、R 2 are each independently any one selected from the group consisting of a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 6 to 12 carbon atoms. When n and m are 2 or more, a plurality of R 1 、R 2 They may be the same group or different groups. Additionally, the alkyl group having 1 to 12 carbon atoms, the cycloalkyl group having 1 to 12 carbon atoms, the alkoxy group having 1 to 12 carbon atoms, and the aryl group having 6 to 12 carbon atoms may be either substituted or unsubstituted.

[0072] As R 1 、R 2 , for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a tert-butyl group, a n-pentyl group, an isopentyl group, a n-hexyl group, a n-heptyl group, a n-octyl group, a n-nonyl group, a n-decyl group, a n-undecyl group, a n-dodecyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group, a n-butoxy group, an isobutoxy group, a tert-butoxy group, a n-pentyloxy group, an isopentyloxy group, a n-hexyloxy group, a n-heptyloxy group, a n-octyloxy group, a n-nonyloxy group, a n-decyloxy group, a n-undecyloxy group, a n-dodecyloxy group, a benzyl group, a phenyl group, a tolyl group, a 2,6-dimethylphenyl group, etc. can be cited.

[0073] R 1 、R 2 Preferably, they are each independently an alkyl group having 1 to 12 carbon atoms, and more preferably, they are each independently an alkyl group having 1 to 5 carbon atoms.

[0074] In formula (A), n and m are each independently an integer from 0 to 3. Preferably, n and m are each independently from 0 to 2, and more preferably, they are each independently 0 or 1.

[0075] Among them, formula (A) is preferably the following formula (A2).

[0076] [Chemical formula 5]

[0077]

[0078] In formula (A2), X has the same meaning as in formula (A). The preferred mode is also the same as that of formula (A). In formula (A2), X is preferably an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, or a fluorenylidene group, more preferably an alkylidene group having 1 to 8 carbon atoms, and further preferably propane-2,2-diyl.

[0079] In formula (A2), R 3 is any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 6 to 12 carbon atoms. R 3 is preferably a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and further preferably a hydrogen atom or a methyl group.

[0080] In formula (A2), preferably X is propane-2,2-diyl, and R 3 is a hydrogen atom or a methyl group.

[0081] Specifically, the bisphenol unit of the structural unit represented by the above formula (A) is a unit of bisphenol such as 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 3,3-bis(4-hydroxyphenyl)pentane, 3,3-bis(4-hydroxy-3-methylphenyl)pentane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxy-3-methylphenyl)pentane, 3,3-bis(4-hydroxyphenyl)heptane, 3,3-bis(4-hydroxy-3-methylphenyl)heptane, 2,2-bis(4-hydroxyphenyl)heptane, 2,2-bis(4-hydroxy-3-methylphenyl)heptane, 4,4-bis(4-hydroxyphenyl)heptane, 4,4-bis(4-hydroxy-3-methylphenyl)heptane, etc., but is not limited to any of them.

[0082] Among them, the bisphenol unit of the structural unit represented by the above formula (A) is preferably a structure selected from any one of the group consisting of 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, and 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, more preferably a structure from 2,2-bis(4-hydroxyphenyl)propane or 2,2-bis(4-hydroxy-3-methylphenyl)propane, and particularly preferably a structure from 2,2-bis(4-hydroxyphenyl)propane.

[0083] Post-consumer materials used as waste polycarbonate resin compositions generally refer to used polycarbonate resin compositions that have been assembled into products as molded articles or used by consumers indoors and outdoors as outer packaging. As molded articles, examples include casings of electronic devices, sundries, lighting lamps, interior and exterior automotive decorations, transport containers, building materials, etc. In addition, pre-consumer materials include purification resins generated by polymerization and compounding, polycarbonate resins with substandard product quality, etc.

[0084] From the viewpoint of environmental load, the waste polycarbonate resin composition is preferably a post-consumer material. As the usage time (the time of being used), it is preferably 3 years or more, more preferably 5 years or more, and further preferably 7 years or more. If the usage time is too short, although the polycarbonate resin (used polycarbonate resin) in the used polycarbonate resin composition has not deteriorated, it is still recycled, so it is not preferred from the aspect of environmental load. On the other hand, if the usage time is too long, the used polycarbonate resin deteriorates significantly, and even if it is regenerated, it may not be possible to fully recover the physical properties. Therefore, as the usage time, it is preferably 30 years or less, more preferably 20 years or less.

[0085] As the waste polycarbonate resin composition, a composition containing a waste polycarbonate resin with an Mw / Mn of 2.8 or more can be used. Generally, post-consumer materials tend to have a decrease in molecular weight due to ultraviolet degradation, so there is a tendency for the value of Mw / Mn to increase. Therefore, a composition with an Mw / Mn of the waste polycarbonate resin of 2.9 or more, 3.0 or more, etc. can also be used.

[0086] The waste polycarbonate resin composition can be used directly in the form of the resin composition of the post-consumer material or pre-consumer material, or can be appropriately divided into an appropriate size by cutting, crushing, pulverizing, etc. The dividing methods such as cutting, crushing, and pulverizing are not particularly limited, and the following methods can be used: cutting using a cutting tool; fusing by cutting with gas, plasma, laser, etc.; severing; cutting using a shredder; coarse crushing to 20 cm or less using a jaw crusher or rotary crusher; medium crushing to 1 cm or less using a rotary crusher, cone crusher, or mill; pulverizing to 1 mm or less using a mill, etc. These methods can be carried out alone or in combination of multiple methods.

[0087] When the shape of the waste polycarbonate resin composition is too large, the dissolution time will be long, which is not preferred. Therefore, it is preferred to use a pulverized body obtained by pulverizing the polycarbonate resin composition as the waste polycarbonate resin composition. The pulverized body of the polycarbonate resin composition preferably has a shape of 53 mm or less, more preferably 22.4 mm or less, and still more preferably 11.2 mm or less. On the other hand, if the shape is too small, it may fly as dust when put into the device, so it is preferably 2.8 mm or more, more preferably 4.75 mm or more.

[0088] It should be noted that "below 53 mm" means passing through a sieve with a nominal mesh size of 53 mm specified in JIS-Z-8801-1 (2019), "below 22.4 mm" means passing through a sieve with a nominal mesh size of 22.4 mm, and "below 11.2 mm" means passing through a sieve with a nominal mesh size of 11.2 mm. In addition, "above 2.8 mm" means not passing through a sieve with a nominal mesh size of 2.8 mm, and "above 4.75 mm" means not passing through a sieve with a nominal mesh size of 4.75 mm.

[0089] (Washing of waste polycarbonate resin composition)

[0090] In addition, the waste polycarbonate resin composition can be dissolved in a good solvent after being washed with water and an organic solvent. Examples of the organic solvent include acetone, acetonitrile, ethanol, methanol, hexane, cyclohexane, heptane, and methyl isobutyl ketone (MIBK). They can also be used in combination. By removing only the surface-deteriorated polycarbonate resin by washing without dissolving the waste polycarbonate resin itself, the quality of the obtained recycled polycarbonate resin can be improved.

[0091] (Good solvent)

[0092] The good solvent for dissolving the waste polycarbonate resin composition contains dichloromethane and / or a phenolic solvent. Examples of the phenolic solvent include phenol, cresol, xylenol, ethylphenol, propylphenol, butylphenol, methoxyphenol, ethoxyphenol, propoxyphenol, butoxyphenol, benzylphenol, phenylphenol, chlorophenol, dichlorophenol, and chloromethylphenol. Among them, dichloromethane, phenol, cresol, and catechol are preferred. The ratio of dichloromethane and / or the phenolic solvent can be any ratio as long as it is a ratio for dissolving the waste polycarbonate resin composition. Preferably, their total is 10% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more relative to the good solvent. That is, when the good solvent contains dichloromethane and does not contain a phenolic solvent, preferably the ratio of dichloromethane to the good solvent is in the aforementioned range; when the good solvent contains a phenolic solvent and does not contain dichloromethane, preferably the ratio of the phenolic solvent to the good solvent is in the aforementioned range; when the good solvent contains dichloromethane and a phenolic solvent, preferably the total ratio of dichloromethane and the phenolic solvent to the good solvent is in the aforementioned range.

[0093] When other resins are included in the waste polycarbonate resin composition, when a solvent containing a phenolic solvent is selected as a good solvent for the waste polycarbonate resin composition, the ratio of the phenolic solvent to the good solvent is preferably 50% by mass or less. This is because when polyesters such as PET and PBT are included in the polycarbonate resin composition, they may also dissolve in the phenolic solvent. Therefore, when other resins are included in the waste polycarbonate resin composition, the lower limit of the ratio of the phenolic solvent to the good solvent is preferably 10% by mass or more, more preferably 20% by mass or more, and the upper limit is preferably 50% by mass or less.

[0094] On the other hand, when a solvent containing dichloromethane is selected as a good solvent, even if the waste polycarbonate resin composition contains other resins, the ratio of dichloromethane to the good solvent is not particularly limited. Therefore, the lower limit of the ratio of dichloromethane to the good solvent is preferably 10% by mass or more, more preferably 20% by mass or more, and furthermore, it may be 100% by mass of dichloromethane.

[0095] The good solvent may also contain solvents other than dichloromethane and phenolic solvents. Specifically, aromatic hydrocarbon solvents such as toluene and xylene can be cited; cyclohexanone; tetrahydrofuran (THF); acetonitrile; dimethyl carbonate; hexafluoroisopropanol; water, etc. The good solvent can use these solvents in an appropriate combination so that the waste polycarbonate resin composition dissolves at the dissolution temperature.

[0096] As the amount of the good solvent, relative to the mass of the waste polycarbonate resin composition, it is preferably 200% by mass or more, more preferably 250% by mass or more, and further preferably 350% by mass or more. When the ratio of the good solvent is small, the viscosity of the solution becomes extremely high, stirring and dissolution become difficult, the filtration rate decreases during filtration, or the filtrate adheres to the filter material, which may lead to a decrease in the yield. In addition, the amount of the good solvent relative to the mass of the waste polycarbonate resin composition is preferably 5000% by mass or less, more preferably 4000% by mass or less, and further preferably 3000% by mass or less. When the ratio of the good solvent is large, the solubility in the polycarbonate resin becomes large, and even when a poor solvent is added in step (3), more polycarbonate resins that do not precipitate in the dissolved state in the good solvent increase, and as a result, the yield may deteriorate. Therefore, relative to the mass of the waste polycarbonate resin composition, the amount of the good solvent is preferably 200% by mass or more and 5000% by mass or less, more preferably 250% by mass or more and 4000% by mass or less, and further preferably 350% by mass or more and 3000% by mass or less.

[0097] (Dissolution temperature)

[0098] When dissolving the waste polycarbonate resin composition in a good solvent, it is preferable to control the temperature (the temperature of the solution in the dissolution tank). Without controlling the temperature, the dissolution time becomes non-uniform, and undissolved components etc. will be generated when feeding the liquid to the next process. As the temperature, it is preferably below the boiling point of the good solvent. If it exceeds the boiling point of the good solvent, a condenser is required for the dissolution tank and the process becomes complicated. As the temperature of the specific good solvent (the temperature of the solution in the dissolution tank), it is preferably 10°C or higher, more preferably 15°C or higher, and further preferably 20°C or higher. When the temperature is too low, the solubility of the polycarbonate resin decreases and the dissolution takes time. Also, when feeding the liquid to the next process, sometimes the liquid feeding takes time, or a large load is imposed on the filtration during filtration. Also, it is preferably 140°C or lower, more preferably 130°C or lower, and further preferably 120°C or lower. When the temperature is too high, the polycarbonate resin will deteriorate due to heat and may be colored. Therefore, the dissolution temperature is preferably 10 to 140°C, more preferably 15 to 130°C, and further preferably 20 to 120°C.

[0099] (Dissolution time)

[0100] The dissolution time is preferably 20 minutes or longer, more preferably 40 minutes or longer, and further preferably 1 hour or longer. Also, it is preferably 5 hours or shorter, more preferably 4 hours or shorter, and further preferably 3 hours or shorter. If the dissolution time is too short, there will be more undissolved components, and the yield may decrease or blockages etc. may occur in the process. When it is too long, decomposition and coloring of the polymer may be caused. Therefore, the dissolution time is preferably 20 minutes to 5 hours, more preferably 40 minutes to 4 hours, and further preferably 1 hour to 3 hours.

[0101] (Removal of undissolved matter)

[0102] When the solution (polycarbonate resin solution) obtained in step (S1) has no undissolved matter and is a homogeneous solution, it can be directly used in step (S2). On the other hand, when the polycarbonate resin solution contains undissolved matter (degraded products, foreign resins, additives, contaminants etc.) and is a suspension solution, it is necessary to perform a process of removing the undissolved matter from the polycarbonate resin solution to obtain a solution (L) with undissolved matter removed before step (S2), and the obtained solution (L) is used in step (S2).

[0103] As a method for removing insoluble matters from a polycarbonate resin solution, methods using filters such as filtration, centrifugal separation, and cyclone filtration can be cited; methods of performing solid-liquid separation from the insoluble matters by means of standing separation, centrifugal separation, flotation separation, etc. and taking out the liquid side. In the case of removing insoluble matters using a filter, any one of filter paper, glass filter, bag filter, candle filter, etc. can be used. Further, the filter can also be used in multiple stages and multiple methods. As the minimum mesh size of the filter material, it is preferably 5 μm or less, more preferably 2 μm or less, and still more preferably 1 μm or less. When the mesh size is too large, the removal of foreign matters becomes insufficient, and when it is too small, there is a tendency for the filterability to deteriorate.

[0104] (Filter aid)

[0105] In order to smoothly remove deteriorated products, foreign resins, additives, and contaminants contained in the waste polycarbonate resin composition, a filter aid can be used. That is, before the step (S2), a step of bringing the polycarbonate resin solution into contact with the filter aid and then removing insoluble matters to obtain a solution (L) from which insoluble matters have been removed can be included, and this solution (L) is used in the step (S2).

[0106] Specific examples of the filter aid include diatomaceous earth, activated clay, alumina, activated carbon, silica gel, cellulose, bentonite, zeolite, synthetic adsorbents, etc. Among them, one or more filter aids selected from the group consisting of diatomaceous earth, activated clay, activated carbon, and synthetic adsorbents are preferred.

[0107] As the activated clay, Galleon Earth (registered trademark), Galleonite (registered trademark), Celite manufactured by Mizusawa Chemical Industry Co., Ltd., Nikkanite manufactured by Toa Kasei Co., Ltd., etc. can be cited.

[0108] As the shape of the activated carbon, powder form, granular form (crushed, particulate, spherical, cylindrical, etc.), fibrous form, etc. can be cited, and any shape can be used. Further, as the raw material of the activated carbon, any one of sawdust, coconut shell, coal, charcoal, etc. can be used. The activated carbon can be an activated carbon that has been activated by a method such as gas activation method, steam activation method, or chemical activation method.

[0109] The synthetic adsorbent is a crosslinked polymer having a porous structure. As the synthetic adsorbent, aromatic type, aromatic modified type, methacrylic acid type, etc. can be cited, and any one can be used. Specifically, Sepabeads (registered trademark) manufactured by Mitsubishi Chemical Corporation, etc. can be cited.

[0110] The method of contacting the polycarbonate resin solution with the filter aid is not particularly limited. The filter aid can be mixed during the preparation of the polycarbonate resin solution in step (S1), or the filter aid can be contacted after the polycarbonate resin solution is prepared in step (S1). In addition, multiple methods can be combined to contact the polycarbonate resin solution with the filter aid one or more times.

[0111] For example, in step (S1), the waste polycarbonate resin composition, the good solvent, and the filter aid are mixed to dissolve the polycarbonate resin in the good solvent. In the resulting solution, the polycarbonate resin is dissolved to form a suspension solution in which the filter aid is dispersed. This suspension solution can be filtered, and the filtrate (solution (L)) can be used in step (S2).

[0112] In addition, when contacting the filter aid after preparing the polycarbonate resin solution in step (S1), the filter aid can be directly added to the polycarbonate resin solution for contact, or can be loaded onto a filter material for contact with the polycarbonate resin solution. In addition, the filter aid can be loaded in a columnar shape, and the polycarbonate resin solution can be contacted by flowing through it.

[0113] The amount of the filter aid used can be any amount as long as it can sufficiently adsorb the coloring components and impurities. The amount of the filter aid used is preferably 10% by mass or more, more preferably 20% by mass or more, further preferably 30% by mass or more, and can also be 40% by mass or more, based on the mass of the dissolved waste polycarbonate resin composition. When the amount of the filter aid is too small, it may not be possible to sufficiently remove the coloring components and impurities. In addition, the amount of the filter aid used is preferably 5000% by mass or less, more preferably 2000% by mass or less, based on the mass of the dissolved waste polycarbonate resin composition. When the amount of the filter aid is too large, impurity components eluted from the filter aid may be contained in a large amount in the recycled polycarbonate resin. Therefore, the amount of the filter aid used is preferably 10 to 5000% by mass, more preferably 20 to 5000% by mass, further preferably 30 to 2000% by mass, based on the mass of the dissolved waste polycarbonate resin composition.

[0114] The filter aid can be reused by being regenerated before and after use. In the regeneration of the filter aid before and after use, the filter aid can be washed with steam, heat, or an organic solvent. By washing, the impurities contained in the filter aid are removed, which is sometimes effective in reducing the impurities in the obtained recycled polycarbonate resin.

[0115] [Step (S2)]

[0116] Step (S2) is a step of precipitating the recycled polycarbonate resin by mixing the polycarbonate resin solution with a poor solvent.

[0117] (Poor solvent)

[0118] The poor solvent used in step (S2) is for precipitating the recycled polycarbonate resin and contains one or more selected from the group consisting of ketone solvents, alcohol solvents, saturated hydrocarbon solvents, and water. Specifically, examples include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone (MIBK), and cyclohexanone; alcohol solvents such as methanol, ethanol, and isopropyl alcohol; saturated hydrocarbon solvents such as hexane, heptane, and cyclohexane; and water.

[0119] In addition, as long as the poor solvent can precipitate the recycled polycarbonate resin, it may also contain solvents other than ketone solvents, alcohol solvents, saturated hydrocarbon solvents, and water. Examples of these solvents include toluene, xylene; THF; acetonitrile; dimethyl carbonate; hexafluoroisopropanol, etc.

[0120] The poor solvent more preferably contains one or more selected from the group consisting of acetone, ethanol, water, methanol, isopropyl alcohol, hexane, cyclohexane, heptane, and MIBK. Among them, acetone has a low boiling point, so solvent recovery and the like become easy, and thus it is preferred.

[0121] The ratio of one or more solvents selected from the group consisting of ketone solvents, alcohol solvents, saturated hydrocarbon solvents, and water can be any ratio as long as it is the ratio at which the polycarbonate resin precipitates. Relative to the total amount of the poor solvent, their total is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 30% by mass or more.

[0122] The mass of the poor solvent relative to the waste polycarbonate resin composition is preferably 200% by mass or more, more preferably 250% by mass or more, and still more preferably 350% by mass or more. When the ratio of the poor solvent is small, precipitation may not occur sufficiently, or the fluidity may decrease in the subsequent step (S3). In addition, the poor solvent is preferably 5000% by mass or less, more preferably 4000% by mass or less, and still more preferably 3000% by mass or less, relative to the waste polycarbonate resin composition. When the ratio of the poor solvent is large, the polycarbonate resin may also dissolve in the poor solvent, and as a result, the yield may deteriorate. Therefore, the amount of the poor solvent is preferably 200% by mass or more and 5000% by mass or less, more preferably 250% by mass or more and 4000% by mass or less, and still more preferably 350% by mass or more and 3000% by mass or less, relative to the mass of the waste polycarbonate resin composition.

[0123] When adding a poor solvent to precipitate (precipitate) the recycled polycarbonate resin, it is preferable to control the temperature (the temperature of the solution in the apparatus). Without controlling the temperature, the precipitation time becomes uneven, and when feeding the liquid to the next process, sometimes the precipitation is insufficient and the yield deteriorates. As the temperature during the precipitation operation, it is preferably below the boiling points of the good solvent and the poor solvent. If it exceeds the boiling points of the good solvent and the poor solvent, the solubility of the polycarbonate resin will increase, and it will be difficult to sufficiently recover the polycarbonate resin. As the specific solution temperature (the temperature of the solution in the apparatus) during the precipitation operation, it is preferably 10 °C or higher, more preferably 15 °C or higher, and further preferably 20 °C or higher. When the temperature is too low, when feeding the liquid to the next process, sometimes it takes time to feed the liquid, or a large load is imposed on the filtration during filtration. In addition, it is preferably 140 °C or lower, more preferably 130 °C or lower, and further preferably 120 °C or lower. When the temperature is too high, the polycarbonate resin will deteriorate due to heat and may become colored. Therefore, the temperature for precipitating the recycled polycarbonate resin is preferably 10 to 140 °C, more preferably 15 to 130 °C, and further preferably 20 to 120 °C.

[0124] The good solvent and the poor solvent are preferably a combination of a good solvent containing dichloromethane and / or a phenolic solvent and a poor solvent containing any one selected from the group consisting of a ketone solvent, an alcohol solvent, a saturated hydrocarbon solvent, and water. More preferably, in the aforementioned combination, the good solvent used in step (S1) and the poor solvent used in step (S2) are each 200% by mass or more and 5000% by mass or less based on the waste polycarbonate resin composition.

[0125] The ratio of the poor solvent to the good solvent is preferably 0.4 times or more, more preferably 1 time or more, and preferably 2 times or less. If the ratio of the poor solvent to the good solvent is too small, the amount of the precipitated recycled polycarbonate resin will be small. If it is too large, there is a possibility that the process becomes excessive or the solvent recovery load becomes large. Therefore, the ratio of the poor solvent to the good solvent is preferably 0.4 to 2 times, more preferably 1 to 2 times.

[0126] [Step (S3)]

[0127] Step (S3) is a step of recovering the aforementioned recycled polycarbonate resin.

[0128] (Trapping of the recycled polycarbonate resin)

[0129] Through step (S2), a suspension in which the precipitated recycled polycarbonate resin is suspended in a solvent (good solvent and poor solvent) is obtained. The recycled polycarbonate resin in this suspension can be trapped by methods such as centrifugation and filtration. The temperature of the suspension is preferably 10 °C or higher and 120 °C or lower. If it is too low, the viscosity increases. If the temperature is too high, there is a possibility of resin deterioration.

[0130] Since the recycled polycarbonate resin collected contains solvents (good solvents, poor solvents), it is preferably dried under reduced pressure or normal pressure. As the drying temperature, it is preferably 30 to 120 °C. When the drying temperature is too low, drying takes time, and when it is too high, there is a possibility that the polycarbonate resin deteriorates.

[0131] (Solvents used)

[0132] The solvents used in each stage are preferably separated by distillation or membrane and reused as good solvents and poor solvents, respectively. In addition, when reusing, 2 to 30% by mass can be discarded. When the discarded amount is small, impurities in the process remain, which may increase the impurities in the recycled polycarbonate resin. On the other hand, when the discarded amount is too large, more solvents are used, resulting in a greater environmental load.

[0133] It should be noted that steps (S1) to (S3) can also be repeated multiple times. That is, the recycled polycarbonate resin recovered in step (S3) can be redissolved in a good solvent and then a poor solvent can be added to precipitate it. In each step, the same solvent or different solvents can be used. When steps (S1) to (S3) are repeated, the number of times can be appropriately determined according to the use, etc., using, for example, the Mw / Mn, L value, etc. of the recycled polycarbonate resin described below as an index. By repeating steps (S1) to (S3) multiple times, the impurities contained in the recycled polycarbonate decrease. On the other hand, when it is excessive, the recovery amount may decrease. Therefore, when steps (S1) to (S3) are repeated, the number of times is preferably 2 to 3 times.

[0134] [Recycled polycarbonate resin]

[0135] The recycled polycarbonate resin obtained by the method for producing a recycled polycarbonate resin of the present invention (hereinafter, sometimes only referred to as "recycled polycarbonate resin") has substantially the same structure as most of the foregoing waste polycarbonate resin, preferably contains the structural unit represented by the above formula (A), and has the following characteristics.

[0136] (Mw / Mn)

[0137] The Mw / Mn of the recycled polycarbonate resin is 2.2 or less, more preferably 2.1 or less, and further preferably 2.0 or less. When it is higher than 2.2, there is a tendency for mechanical properties, color tone, and weather resistance to deteriorate. The lower limit of Mw / Mn is not particularly limited and can be arbitrarily set to 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, etc. The lower limit of Mw / Mn can be appropriately selected in consideration of manufacturing efficiency, etc. Therefore, the Mw / Mn of the recycled polycarbonate resin is preferably 1.4 to 2.2, more preferably 1.5 to 2.1, and further preferably 1.5 to 2.0.

[0138] (Terminal hydroxyl group (terminal OH))

[0139] When the content of terminal hydroxyl group is low, hydrolysis resistance becomes good, so the terminal hydroxyl group of unused polycarbonate resin that is usually used is less than 150 mass ppm. On the other hand, due to the influence of deterioration, the terminal hydroxyl group of waste polycarbonate resin is more than 200 mass ppm in most cases. In the recycled polycarbonate resin of the present invention, the lower limit of the content of terminal hydroxyl group is usually more than 200 mass ppm and more than 210 mass ppm. In order to make the content of terminal hydroxyl group of recycled polycarbonate resin less than 200 mass ppm, it is necessary to screen the waste polycarbonate resin composition, which becomes a large burden as a whole for manufacturing. On the other hand, when the terminal hydroxyl group is too high, the possibility of deterioration of hydrolysis resistance (weather resistance) is high. Therefore, the content of terminal hydroxyl group of recycled polycarbonate resin is preferably smaller in the order of less than 530 mass ppm, less than 520 mass ppm, less than 510 mass ppm, and less than 500 mass ppm. Therefore, the content of the terminal hydroxyl group in the recycled polycarbonate resin is preferably 200 to 530 mass ppm, more preferably 200 to 520 mass ppm, and further preferably 210 to 510 mass ppm.

[0140] (Content of the structural unit represented by formula (1))

[0141] The recycled polycarbonate resin preferably contains 200 to 1100 ppm by mass of a structural unit represented by the following formula (1) (hereinafter referred to as "branch component (1)") in its main chain.

[0142] [Chemistry 6]

[0143]

[0144] X, R in formula (1) 1 , R 2 , n, and m have the same meanings as in formula (A). X, R 1 , R 2 , n, m and X, R of formula (A) 1 , R 2 , n, and m have the same meaning. For example, if X in formula (A) is a single bond, then X in formula (1) is also a single bond.

[0145] The recycled polycarbonate resin preferably contains a structural unit represented by formula (A2), and formula (1) is preferably the following formula (2).

[0146] [Chemical 7]

[0147]

[0148] In formula (2), X, R 3 has the same meaning as in formula (A2), and X, R in formula (2) 3 has the same meaning as X, R in formula (A2) 3 are the same.

[0149] Similar to formula (A2), in formula (2), preferably X is propane-2,2-diyl, and R 3 is a hydrogen atom or a methyl group.

[0150] In the case of commonly used unused polycarbonate resins, almost all have a content of the branched component (1) less than 200. On the other hand, waste polycarbonate resins deteriorate due to heat and ultraviolet rays, and in most cases, the content of the branched component (1) is 250 mass ppm or more. In the recycled polycarbonate resin of the present invention, the lower limit of the content of the branched component (1) is also usually 200 mass ppm or more, 250 mass ppm or more. In order to make the content of the branched component (1) in the recycled polycarbonate resin equivalent to that of the unused polycarbonate resin, it is necessary to screen the waste polycarbonate resin composition, which is a large burden as a whole for manufacturing. On the other hand, when the branched component (1) is excessive, there is a tendency for the mechanical properties and weather resistance to deteriorate. Therefore, the content of the branched component (1) in the recycled polycarbonate resin is preferably 1100 mass ppm or less, more preferably 1000 mass ppm or less, and further preferably 900 mass ppm or less.

[0151] (Viscosity-average molecular weight)

[0152] The viscosity-average molecular weight (Mv) converted from the solution viscosity of the recycled polycarbonate resin is preferably greater than 19,000, more preferably 20,000 or more, and still more preferably 21,000 or more. There is no particular limitation on the upper limit, and it is preferably 33,000 or less. When the viscosity-average molecular weight is below the above lower limit, the mechanical properties and alkali resistance of the recycled polycarbonate resin of the present invention are reduced, so it is not preferred. In addition, when the viscosity-average molecular weight exceeds the above upper limit, the fluidity of the recycled polycarbonate resin of the present invention tends to become insufficient, so it is not preferred. From this point of view, the viscosity-average molecular weight (Mv) of the recycled polycarbonate resin of the present invention is preferably greater than 19,000 and 33,000 or less, more preferably 20,000 or more and 33,000 or less, and still more preferably 21,000 or more and 33,000 or less.

[0153] (L value)

[0154] The L value based on reflection measurement of the recycled polycarbonate resin is preferably 80 or more, more preferably 85 or more, and still more preferably 90 or more. When the L value is low, when the recycled polycarbonate resin is formed into a molded article, the color difference or transparency is low.

[0155] (3mmYI)

[0156] When measuring the yellow index (YI) value (3mmYI) of a 3-mm-thick molded body formed from the recycled polycarbonate resin according to ASTM D1925, it is preferably 2.2 or less, more preferably 2.1 or less, and still more preferably 2.0 or less. If 3mmYI is too high, it has a yellowish tint and is often restricted in the applicable uses.

[0157] (Weather resistance test)

[0158] For a 3-mm-thick molded body formed from the recycled polycarbonate resin, as the ΔYI of the increase in YI after irradiating with a xenon lamp at an illuminance of 60 W / m 2 for 25 hours is preferably 1.5 or less, more preferably 1.4 or less, and still more preferably 1.3 or less. When ΔYI is too high, yellowing occurs during outdoor use and the uses are restricted.

[0159] (Izod impact strength (low-temperature impact))

[0160] The Izod impact strength (notched Izod impact strength at low temperature) measured at -20 °C according to ASTM D256 is preferably 150 J / m or more, more preferably 180 J / m or more, and still more preferably 230 J / m or more. When it is too low, it is brittle during special use at low temperature and there is a high possibility that the inherent properties of polycarbonate cannot be exerted.

[0161] [Method of Using Recycled Polycarbonate Resin]

[0162] As a material with a small environmental load, recycled polycarbonate resin can be used for the same applications as virgin polycarbonate resin. For example, recycled polycarbonate resin can be widely used for applications such as casings, screens of mobile phones, automotive interior / exterior trims, displays, medical devices, building materials, etc.

[0163] Recycled polycarbonate resin can be used to produce a molded article solely with 100% of the total amount, or can be used in combination with waste polycarbonate resin and virgin (new) polycarbonate resin. In addition, additives can be incorporated, or a polymer alloy with other resins other than polycarbonate resin can be produced. Regarding additives and alloys, commonly used additives and alloys can be appropriately used.

[0164] Recycled polycarbonate resin can be used, for example, in a method for manufacturing a molded article that includes a process of obtaining recycled polycarbonate resin by the manufacturing method of the recycled polycarbonate resin of the present invention and a process of obtaining a molded article using the obtained recycled polycarbonate resin. Thus, a molded article containing recycled polycarbonate resin can be obtained. Examples of the molded article include: pellets; members or products such as casings, automotive interior / exterior trim members, display members, medical device members, building materials, etc. The method for obtaining the molded article can be the same as the method used for virgin polycarbonate resin in the past, and other resins and additives can be appropriately incorporated. Members or products can be manufactured using recycled polycarbonate resin, or can also be manufactured using pellets formed from recycled polycarbonate resin.

[0165] Examples

[0166] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples as long as the gist thereof is not changed.

[0167] [Weight-Average Molecular Weight (Mw), Number-Average Molecular Weight (Mn), and Mw / Mn]

[0168] The analysis apparatus used was "HLC-8020" manufactured by Tosoh Corporation. Regarding the columns, four columns (diameter 7.8 mm, length 300 mm) filled with "TSK5000HLX", "4000HLX, 3000HLX", and "2000HLX" manufactured by Tosoh Corporation as fillers were connected and used. The eluent used was tetrahydrofuran.

[0169] The standard curve was prepared using standard polystyrenes manufactured by Chemco Co., Ltd. (molecular weights: 761 (Mw / Mn ≤ 1.14), 2,000 (Mw / Mn ≤ 1.20), 4,000 (Mw / Mn ≤ 1.06), 9,000 (Mw / Mn ≤ 1.04), 17,500 (Mw / Mn ≤ 1.03), 50,000 (Mw / Mn ≤ 1.03), 233,000 (Mw / Mn ≤ 1.05), 600,000 (Mw / Mn ≤ 1.05), and 900,000 (Mw / Mn ≤ 1.05)).

[0170] During the measurement, from the graph detected by refractive index, Mw and Mn were determined in terms of polystyrene conversion, and Mw / Mn was calculated.

[0171] [Viscosity-average molecular weight (Mv)]

[0172] The viscosity-average molecular weight [Mv] was determined by using dichloromethane as a solvent and an Ubbelohde viscometer to obtain the intrinsic viscosity [η] (unit: dl / g) at 20 °C, and calculated from Schnell's viscosity equation, i.e., η = 1.23×10 -4 Mv 0.83 The calculated value. It should be noted that the intrinsic viscosity [η] refers to the value calculated by the following formula for the specific viscosity [η sp at each solution concentration [C] (g / dl).

[0173] [Equation 1]

[0174]

[0175] [Content of terminal hydroxyl groups]

[0176] The amount of terminal hydroxyl groups in the polycarbonate resin was determined by colorimetric quantification according to the colorimetric quantification method using titanium tetrachloride / acetic acid method (the method described in Macromol.Chem. 88 215 (1965)).

[0177] [Content of the compound (PSA) represented by the formula (1) contained in the polycarbonate resin]

[0178] After dissolving 0.5 g of the polycarbonate resin in 5 mL of dichloromethane, 45 mL of methanol and 5 mL of 25 mass% aqueous sodium hydroxide solution were added, and hydrolysis was carried out by stirring at 70 °C for 30 minutes (dichloromethane solution). Then, 6 N hydrochloric acid was added to the dichloromethane solution to adjust the pH of the solution to about 2, and the volume was adjusted to 100 mL with pure water.

[0179] Next, 20 μL of the prepared dichloromethane solution was injected into a liquid chromatograph to measure the content of the compound represented by the formula (1) (unit: mass ppm).

[0180] The liquid chromatography and measurement conditions are as follows.

[0181] · Liquid chromatography: LC-10AD manufactured by Shimadzu Corporation

[0182] · Column: YMC PACK ODS-AM M-307-3 4.6 mm ID × 75 mm L

[0183] · Detector: UV 280 nm

[0184] · Eluent: (A) 0.05 vol% aqueous trifluoroacetic acid solution (B) methanol

[0185] · Gradient conditions: 0 min (B = 40 vol%), 25 min (B = 95 vol%)

[0186] The content of the compound (PSA) shown in formula (1) is calculated from the respective peak areas based on a standard curve made from bisphenol A.

[0187] [L value]

[0188] After putting the polycarbonate resin into a circular sample cell, cover the ZERO BOX and measure in reflection mode with a spectrophotometer SE6000 manufactured by Nippon Denshoku Industries Co., Ltd. to obtain the L value.

[0189] [3 mm YI (yellow index)]

[0190] Using a small injection molding machine (Shinko SELLBIC C Co., Ltd., Mobile), a polycarbonate resin plate with a thickness of 3 mm, a length of 25 mm, and a width of 25 mm was molded.

[0191] The color tone of the obtained molded body (plate) was measured using a spectrophotometer CM-5 manufactured by Konica Minolta Inc. according to ASTM D1925.

[0192] [ΔYI (weather resistance test)]

[0193] Using a small injection molding machine (Shinko SELLBIC C Co., Ltd., Mobile), a polycarbonate resin plate with a thickness of 3 mm, a length of 25 mm, and a width of 25 mm was molded.

[0194] The obtained molded body (plate) was treated with a light resistance testing machine (Iwatsu Electric EYE SUN-CUBE Xenon SCX400 / 1-1) at an illuminance of 60 W / m 2 for 25 hours, and the YI after treatment was measured in the same manner as YI. The number obtained by subtracting the YI of the initial color tone (3 mm YI) from the YI after treatment was taken as ΔYI.

[0195] [Izod impact strength (low temperature)]

[0196] Using a small injection molding machine (Shinko SELLBIC C, Mobile), under the conditions of the barrel temperature and mold temperature described in each example, a sample of polycarbonate resin with a thickness of 3.2 mm, a length of 53.5 mm, and a width of 12.7 mm was molded to obtain a test piece. For this test piece, according to ASTM D256, at a position 31.8 mm from the end in the longitudinal direction, a cutting notch was made with a notch tip radius of 0.25 mm and a notch depth of 2.54 mm, and using a universal impact tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.), five notched Izod impact tests were carried out at -20 °C respectively.

[0197] [Confirmation of mixing with other resins]

[0198] Using 3 g of polycarbonate resin, it was molded by hot pressing at 260 °C in the form of 7 cm in length × 7 cm in width × 0.5 mm in thickness. Its surface was measured using IR (infrared spectroscopy) to determine whether peaks of resins other than the polycarbonate resin contained in raw materials C and D described below were confirmed.

[0199] [Raw materials]

[0200] The following raw materials A to raw materials C were used.

[0201] Raw material A: Used polycarbonate transparent cup

[0202] Raw material B: Used automotive polycarbonate windshield

[0203] Raw material C: Used printer housing made of polycarbonate-ABS (black)

[0204] Raw material D: Used automotive component PC / PET / GF (black)

[0205] [Reagents, etc.]

[0206] Solvents: Dichloromethane, phenol, cresol, acetone, methanol, ethanol, isopropanol, heptane, toluene, 1,2-dichloroethane, ethyl acetate Reagents manufactured by FUJIFILM Wako Pure Chemical Corporation were used.

[0207] Filter aids: Activated carbon, activated clay, diatomaceous earth Substances manufactured by FUJIFILM Wako Pure Chemical Corporation were used. As a synthetic adsorbent, Sepabeads (registered trademark) SP700 manufactured by Mitsubishi Chemical Corporation was used.

[0208] The raw materials are pre-crushed to about 10 mm square by a crusher before use. In addition, Table 1 shows the Mw / Mn, the content of terminal hydroxyl groups (terminal OH), and the content of the compound represented by formula (1) (PSA) of raw materials A to C. It should be noted that "ppm" in Table 1 has the same meaning as "mass ppm".

[0209] [Table 1]

[0210]

[0211] [Example 1]

[0212] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the crushed product of raw material A was selected, dichloromethane was chosen as a good solvent, 5 kg was supplied, and stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter, acetone was selected as a poor solvent for the filtrate, 6 kg was added, and as a result, a white polycarbonate precipitate was formed. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0213] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 2.

[0214] [Examples 2 - 6]

[0215] Except for selecting the good solvents and poor solvents listed in Table 2, Examples 2 - 6 were carried out in the same manner as Example 1. Instead of the dissolution temperature of 20 °C in Example 1, the dissolution temperatures of Examples 3 - 5 were set to 60 °C, and the dissolution temperature of Example 6 was set to 50 °C. For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 2.

[0216] [Example 7]

[0217] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the crushed product of raw material A and 5 kg of acetone were supplied, and stirring was carried out for 30 minutes. Thereafter, the undissolved and remaining polycarbonate resin was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0218] Next, in a 10 L flask, under a nitrogen atmosphere and at 20 °C, 400 g of the polycarbonate resin dried at 40 °C was supplied. Dichloromethane was selected as a good solvent and 5 kg was supplied, followed by stirring for 30 minutes to dissolve the polycarbonate resin. Acetone was selected as a poor solvent for this solution, 6 kg was added, and as a result, a white polycarbonate precipitate was formed. This polycarbonate precipitate was filtered off with filter paper and dried at 110 °C for 6 hours.

[0219] For the obtained polycarbonate precipitate, perform various physical property evaluations according to the above steps. The results are shown in Table 2.

[0220] [Example 8]

[0221] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, supply 500 g of the pulverized product of raw material A and 5 kg of acetone, and stir for 30 minutes. Thereafter, filter the undissolved and remaining polycarbonate resin using a filter paper, and dry it using a dryer at 40 °C for 10 hours.

[0222] Next, in a 10 L flask, under a nitrogen atmosphere and at 60 °C, supply 400 g of the polycarbonate resin dried at 40 °C. Select phenol as a good solvent and supply 5 kg, then stir for 30 minutes to dissolve the polycarbonate resin. Select acetone as a poor solvent for this solution and add 6 kg, and as a result, a white polycarbonate precipitate is produced. Filter the polycarbonate precipitate using a filter paper and dry it at 110 °C for 6 hours.

[0223] For the obtained polycarbonate precipitate, perform various physical property evaluations according to the above steps. The results are shown in Table 2.

[0224] [Table 2]

[0225]

[0226] [Examples 9 - 16]

[0227] Except for setting the types and amounts of the good solvent and poor solvent as described in Table 3, perform Examples 9 - 16 in the same manner as Example 1. It should be noted that in Examples 15 and 16, phenol and toluene are mixed at a ratio of 1:1 (mass ratio) and used as the good solvent, and the dissolution temperature is set at 60 °C.

[0228] As the yield, calculate the ratio of the mass of the recycled polycarbonate resin obtained after drying to the mass of the raw material used. The results are shown in Table 3.

[0229] [Table 3]

[0230]

[0231] [Example 17]

[0232] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the pulverized product of raw material B was selected, dichloromethane was chosen as the good solvent, 5 kg was supplied, and further 200 g of activated carbon was supplied. Stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter covered with 300 g of activated carbon. Isopropyl alcohol was selected as the poor solvent for the filtrate, and 6 kg was added. As a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0233] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 4.

[0234] [Example 18]

[0235] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the pulverized product of raw material B was selected, dichloromethane was chosen as the good solvent, 5 kg was supplied, and further 200 g of activated clay was supplied. Stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter. Acetone and ethanol were selected as the poor solvents for the filtrate, and 3 kg was added to each. As a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0236] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 4.

[0237] [Example 19]

[0238] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the pulverized product of raw material B was selected, dichloromethane was chosen as the good solvent, 5 kg was supplied, and further 200 g of activated clay was supplied. Stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter covered with 300 g of diatomaceous earth. Acetone was selected as the poor solvent for the filtrate, and 6 kg was added. As a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0239] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 4.

[0240] [Example 20]

[0241] In a 10 L flask, under a nitrogen atmosphere at 60 °C, 500 g of the ground product of raw material B was selected, phenol was chosen as the good solvent, 5 kg was supplied, and further 200 g of activated carbon was supplied, followed by stirring for 30 minutes. Then, the solution was filtered through a glass filter. For the filtrate, isopropanol was selected as the poor solvent, 6 kg was added, and as a result, a white polycarbonate precipitate was formed. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0242] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 4.

[0243] [Example 21]

[0244] In a 10 L flask, under a nitrogen atmosphere at 60 °C, 500 g of the ground product of raw material B was selected, phenol was chosen as the good solvent, 5 kg was supplied, and further 200 g of activated carbon was supplied, followed by stirring for 30 minutes. Then, the solution was filtered through a glass filter. For the filtrate, methanol was selected as the poor solvent, 6 kg was added, and as a result, a white polycarbonate precipitate was formed. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0245] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 4.

[0246] [Example 22]

[0247] In a 10 L flask, under a nitrogen atmosphere at 60 °C, 500 g of the ground product of raw material B was selected, a solvent prepared by mixing phenol and toluene in a mass ratio of 4:6 was chosen as the good solvent, 5 kg was supplied, and further 200 g of activated clay was supplied, followed by stirring for 30 minutes. Then, the solution was filtered through a glass filter. For the filtrate, methanol was selected as the poor solvent, 6 kg was added, and as a result, a white polycarbonate precipitate was formed. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0248] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 4.

[0249] [Table 4]

[0250]

[0251] [Example 23]

[0252] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the ground product of raw material C was selected, dichloromethane was chosen as the good solvent, 5 kg was supplied, and further 200 g of activated clay was supplied, followed by stirring for 30 minutes. Then, the solution was filtered through a glass filter. Acetone was selected as the poor solvent for the filtrate, 6 kg was added, and as a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0253] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 5.

[0254] [Example 24]

[0255] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the ground product of raw material C was selected, dichloromethane was chosen as the good solvent, 5 kg was supplied, and further 500 g of SP700 was supplied, followed by stirring for 30 minutes. Then, the solution was filtered through a glass filter. Warm water (40 °C) was selected as the poor solvent for the filtrate, 6 kg was added, and as a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0256] Next, in a 10 L flask, under a nitrogen atmosphere and at 20 °C, 380 g of the polycarbonate precipitate dried at 40 °C and 5 kg of dichloromethane as the good solvent were supplied, followed by stirring for 30 minutes to dissolve the polycarbonate precipitate. 6 kg of acetone as the poor solvent was added to this solution, and as a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0257] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 5.

[0258] [Example 25]

[0259] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the ground product of raw material D was selected, dichloromethane was chosen as the good solvent, 5 kg was supplied, and further 200 g of activated carbon was supplied, followed by stirring for 30 minutes. Then, the solution was filtered through a glass filter. Acetone was selected as the poor solvent for the filtrate, 6 kg was added, and as a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0260] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 5.

[0261] [Example 26]

[0262] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the pulverized product of raw material C was selected, and a solvent prepared by mixing phenol and toluene in a mass ratio of 3:7 was chosen as the good solvent. 5 kg of the solvent was supplied, and further 200 g of activated carbon was supplied. Stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter. Acetone was selected as the poor solvent for the filtrate, and 6 kg was added. As a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered out with filter paper and dried in a dryer at 40 °C for 10 hours.

[0263] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 5.

[0264] [Example 27]

[0265] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the pulverized product of raw material D was selected, and a solvent prepared by mixing phenol and toluene in a mass ratio of 3:7 was chosen as the good solvent. 5 kg of the solvent was supplied, and further 200 g of activated carbon was supplied. Stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter. Acetone was selected as the poor solvent for the filtrate, and 6 kg was added. As a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered out with filter paper and dried in a dryer at 40 °C for 10 hours.

[0266] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 5.

[0267] [Example 28]

[0268] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the pulverized product of raw material D was selected, and a solvent prepared by mixing phenol and toluene in a mass ratio of 7:3 was chosen as the good solvent. 5 kg of the solvent was supplied, and further 200 g of activated carbon was supplied. Stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter. Acetone was selected as the poor solvent for the filtrate, and 6 kg was added. As a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered out with filter paper and dried in a dryer at 40 °C for 10 hours.

[0269] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 5.

[0270] [Table 5]

[0271]

[0272] [Comparative Example 1]

[0273] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the ground product of raw material A was selected, 1,2-dichloroethane was chosen as the good solvent, 5 kg was supplied, and stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter. For the filtrate, ethyl acetate was selected as the poor solvent, 6 kg was added, and as a result, a gray polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0274] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 6.

[0275] [Comparative Example 2]

[0276] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the ground product of raw material A was selected, dichloromethane was chosen as the good solvent, 5 kg was supplied, and stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter. For the filtrate, ethyl acetate was selected as the poor solvent, 6 kg was added, and as a result, a slightly black polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0277] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 6.

[0278] [Comparative Example 3]

[0279] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the ground product of raw material B was selected, 1,2-dichloroethane was chosen as the good solvent, 5 kg was supplied, and stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter. For the filtrate, ethyl acetate was selected as the poor solvent, 6 kg was added, and as a result, a gray polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0280] For the obtained polycarbonate precipitate, various physical property evaluations were carried out according to the above steps. The results are shown in Table 6.

[0281] [Comparative Example 4]

[0282] In a 10 L flask, under a nitrogen atmosphere and at 20 °C, 500 g of the ground product of raw material B was selected, 1,2-dichloroethane was chosen as the good solvent, 5 kg was supplied, and stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter. For the filtrate, methanol was selected as the poor solvent, 6 kg was added, and as a result, a white polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0283] For the obtained polycarbonate precipitate, each physical property evaluation was carried out according to the above steps. The results are shown in Table 6.

[0284] [Comparative Example 5]

[0285] In a 10 L flask, under a nitrogen atmosphere at 20 °C, 500 g of the ground product of raw material C was selected, 1,2-dichloroethane was used as a good solvent, 5 kg was supplied, and stirring was carried out for 30 minutes. Then, the solution was filtered through a glass filter, ethyl acetate was selected as a poor solvent for the filtrate, 6 kg was added, and as a result, a gray polycarbonate precipitate was produced. The polycarbonate precipitate was filtered off with filter paper and dried in a dryer at 40 °C for 10 hours.

[0286] For the obtained polycarbonate precipitate, each physical property evaluation was carried out according to the above steps. The results are shown in Table 6.

[0287] [Reference Example 1]

[0288] Using S3000N manufactured by Mitsubishi Engineering-Plastics Corporation, each physical property evaluation was carried out according to the above steps. The results are shown in Table 6.

[0289] [Table 6]

[0290]

Claims

1. A method for manufacturing a recycled polycarbonate resin, which is a method for manufacturing a recycled polycarbonate resin from a waste polycarbonate resin composition, wherein the Mw / Mn of the polycarbonate resin contained in the waste polycarbonate resin composition is 2.8 or more, and the Mw / Mn of the recycled polycarbonate resin is 2.2 or less, wherein Mw / Mn is the ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography, and the manufacturing method includes the following steps (S1) to (S3), Step (S1): A step of dissolving the waste polycarbonate resin composition in a good solvent containing dichloromethane and / or a phenolic solvent to obtain a polycarbonate resin solution, Step (S2): A step of precipitating the recycled polycarbonate resin by mixing the polycarbonate resin solution with a poor solvent, the poor solvent containing one or more selected from the group consisting of a ketone solvent, an alcohol solvent, a saturated hydrocarbon solvent, and water, Step (S3): A step of recovering the precipitated recycled polycarbonate resin.

2. The method for manufacturing a recycled polycarbonate resin according to claim 1, before the step (S2), includes a step of bringing the polycarbonate resin solution into contact with one or more filter aids selected from the group consisting of diatomaceous earth, activated clay, activated carbon, and a synthetic adsorbent to remove insoluble matters and obtain a solution (L) from which insoluble matters have been removed, and using the solution (L) as the polycarbonate resin solution in the step (S2).

3. The method for manufacturing a recycled polycarbonate resin according to claim 1, before the step (S2), includes a step of removing insoluble matters from the polycarbonate resin solution to obtain a solution (L) from which insoluble matters have been removed, and using the solution (L) as the polycarbonate resin solution in the step (S2).

4. The method for manufacturing a recycled polycarbonate resin according to claim 1, wherein the proportion of the polycarbonate resin contained in the waste polycarbonate resin composition is 20% by mass or more.

5. The method for manufacturing a recycled polycarbonate resin according to claim 1, wherein the waste polycarbonate resin composition contains one or more selected from the group consisting of other resins, inorganic substances, and low-molecular organic compounds.

6. The method for manufacturing a recycled polycarbonate resin according to claim 4 or 5, wherein the good solvent used in the step (S1) is a solvent containing dichloromethane or a solvent containing 50% by mass or less of a phenolic solvent.

7. The method for manufacturing a recycled polycarbonate resin according to claim 1 or 2, wherein the good solvent used in the step (S1) is 200% by mass or more and 5000% by mass or less relative to the waste polycarbonate resin composition.

8. The method for manufacturing a recycled polycarbonate resin according to claim 1 or 2, wherein the poor solvent used in the step (S2) is 200% by mass or more and 5000% by mass or less relative to the waste polycarbonate resin composition.

9. The method for manufacturing a recycled polycarbonate resin according to claim 1 or 2, wherein the content of terminal hydroxyl groups in the recycled polycarbonate resin is 200 to 530 mass ppm, and the content of the structural unit represented by the following formula (1) contained in the main chain is 200 to 1100 mass ppm. [Chemical formula 1] In formula (1), X is any one selected from the group consisting of a single bond, an alkylene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, a fluorenylidene group, a xanthenylidene group, a thioxanthenylidene group, -O-, -S-, -CO-, -SO-, and -SO2-. R 1 、R 2 are each independently selected from the group consisting of a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 6 to 12 carbon atoms. n and m are each independently an integer of 0 to 3.

10. The method for manufacturing a recycled polycarbonate resin according to claim 1 or 2, wherein the viscosity-average molecular weight of the recycled polycarbonate resin is greater than 19,000.

11. A recycled polycarbonate resin, which is a recycled polycarbonate resin regenerated from a waste polycarbonate resin composition, and the ratio of the weight-average molecular weight Mw to the number-average molecular weight Mn in terms of polystyrene measured by gel permeation chromatography: Mw / Mn is 2.2 or less.

12. The recycled polycarbonate resin according to claim 11, wherein the content of terminal hydroxyl groups in the recycled polycarbonate resin is 200 to 530 mass ppm.

13. The recycled polycarbonate resin according to claim 11 or 12, wherein the content of the structural unit represented by the following formula (1) contained in the main chain of the recycled polycarbonate resin is 200 to 1100 mass ppm. [Chemical formula 2] In formula (1), X is any one selected from the group consisting of a single bond, an alkylene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, a fluorenylidene group, a xanthenylidene group, a thioxanthenylidene group, -O-, -S-, -CO-, -SO-, and -SO2-. R 1 、R 2 are each independently selected from any one of the group consisting of a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 6 to 12 carbon atoms. n and m are each independently an integer of 0 to 3.

14. The recycled polycarbonate resin according to claim 11 or 12, wherein the viscosity-average molecular weight of the recycled polycarbonate resin is greater than 19,000.

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