Method for producing modified polycarbonate resin composition, method for producing bisphenol, regenerated polycarbonate resin, and method for producing regenerated polycarbonate resin composition

Abstract

Provided is a method for producing a modified polycarbonate resin composition suitable as a starting material for chemical recycling and material recycling. A method for producing a modified polycarbonate resin composition, in which a modified polycarbonate resin composition is obtained by dissolving the surface of a waste polycarbonate resin composition in a treatment solvent by solvent treatment in which the waste polycarbonate resin composition having a dichloromethane dissolution color of 110 or more is brought into contact with the treatment solvent. A method for producing a modified polycarbonate resin composition, which comprises subjecting a waste polycarbonate resin composition having a luminance index L * of 20-80 to solvent treatment in which a treatment solvent is brought into contact with the waste polycarbonate resin composition, thereby obtaining a modified polycarbonate resin composition having a difference between the luminance index L * before solvent treatment and the luminance index L * after solvent treatment of 5 or more. Furthermore, a method for producing a modified polycarbonate resin composition, in which a modified polycarbonate resin composition having a heat of fusion of 1.0 J / g or more is obtained by solvent treatment in which a waste polycarbonate resin composition having a maximum side length of 1-1000 mm (inclusive) is brought into contact with a treatment solvent.

Description

Technical Field

[0001] The present invention relates to a method for producing a modified polycarbonate resin composition having an improved hue of a waste polycarbonate resin composition. Further, it relates to a method for producing bisphenol using the modified polycarbonate resin composition as a raw material, and a method for producing a recycled polycarbonate resin and a recycled polycarbonate resin composition. Background Art

[0002] Plastics are essential in modern society due to their excellent functions and properties, and are mass-produced and consumed not only in Japan but also worldwide. For sustainable development, recycling of consumed plastic resources is important, and as means thereof, there are roughly three methods: material recycling as a raw material for plastic products, chemical recycling as a chemical raw material, and thermal recycling as an energy source.

[0003] Regarding the effective utilization rate of waste plastics by each recycling method in Japan, thermal recycling is the highest. The calorific value generated when plastics are burned is not inferior to that of coal and petroleum, and the heat is effectively used for power generation and the like. However, in Europe and the United States, thermal recycling is mostly not regarded as recycling, and further promotion of material recycling and chemical recycling is required. The polycarbonate resin used in a wide range of fields, such as in terms of transparency, mechanical properties, flame retardancy, dimensional stability, and electrical properties, is no exception.

[0004] The polycarbonate resin is excellent in processability and durability, and has high transparency. Therefore, it is used not only for the housings of household electrical appliances, optical recording discs (CDs, etc.), but also for automotive headlamp covers, roof materials for carports, sound insulation walls on highways, etc., which are used outdoors for a long time.

[0005] Many methods for material recycling and chemical recycling of polycarbonate resins have been reported. As a method for material recycling, there is known a method of removing a coating agent on the surface by treating an optical recording disc with an aqueous alkali solution and recovering the polycarbonate resin as a base material (Patent Document 1); a method of dissolving an optical recording disc in a solvent and then precipitating it using a mixed solution of water and alcohol to recover only the polycarbonate resin (Patent Document 2), etc.

[0006] Further, as a method for chemical recycling, there is known a method of hydrolyzing a waste polycarbonate resin and recovering it in the form of an aqueous alkali solution containing a sodium salt of bisphenol (Patent Document 3); a method of alcoholyzing an optical recording disc and recovering bisphenol and dialkyl carbonate (Patent Document 4); a method of phenolyzing a waste polycarbonate resin and recovering bisphenol and diphenyl carbonate (Patent Document 5), etc.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-310970

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2009-84538

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 2005-179460

[0012] Patent Document 4: Japanese Patent Application Laid-Open No. 2001-160243

[0013] Patent Document 5: Japanese Patent Application Laid-Open No. 7-207059 Summary of the Invention

[0014] Problems to be Solved by the Invention

[0015] Polycarbonate resins used outdoors for a long time gradually deteriorate due to exposure to wind and rain, causing discoloration and low molecular weight. Therefore, there is a problem of color tone difference between bisphenol obtained by chemically recycling used polycarbonate resin and bisphenol obtained by chemically recycling the original product (unused polycarbonate resin). The deteriorated part originally has the same composition and properties as the polycarbonate resin in the non-deteriorated part. Therefore, in the method of removing additives such as metal coatings and flame retardants, it is difficult to separate the deteriorated part from the non-deteriorated part.

[0016] On the other hand, when melting used polycarbonate resin for material recycling, there is a problem of generating a strange odor. Therefore, a method of material recycling that suppresses the generation of strange odor is required.

[0017] The present invention has been completed in view of the above-mentioned prior art circumstances, and an object thereof is to provide a method for manufacturing a modified polycarbonate resin composition that can manufacture a modified polycarbonate resin composition suitable as a raw material for chemical recycling and material recycling from a waste polycarbonate resin composition.

[0018] In addition, an object thereof is to provide a method for manufacturing bisphenol using the above-mentioned modified polycarbonate resin composition as a raw material and a method for manufacturing a recycled polycarbonate resin using the bisphenol as a raw material. Further, an object thereof is to provide a method for manufacturing a recycled polycarbonate resin composition using the above-mentioned modified polycarbonate resin composition as a raw material.

[0019] Means for Solving the Problems

[0020] The present inventors have conducted in-depth research to solve the above problems and found that by subjecting a used polycarbonate resin composition to solvent treatment, a modified polycarbonate resin composition suitable as a raw material for producing bisphenol by chemical recycling can be produced. Furthermore, it has been found that the above-mentioned modified polycarbonate resin composition can suppress the generation of abnormal odor during melting and is also suitable as a raw material for material recycling in the production of recycled polycarbonate resin composition. That is, the present invention relates to the following inventions.

[0021] <1> A method for producing a modified polycarbonate resin composition, which comprises subjecting a waste polycarbonate resin composition having a dichloromethane solubility color of 110 or more (for example, 110 or more and 10000 or less, 200 or more and 10000 or less, 300 or more and 10000 or less, 500 or more and 10000 or less, or 700 or more and 10000 or less) to solvent treatment by contacting it with a treatment solvent, so that the surface of the waste polycarbonate resin composition is dissolved in the treatment solvent to obtain a modified polycarbonate resin composition.

[0022] <2> The method for producing a modified polycarbonate resin composition according to the above <1>, wherein the difference between the dichloromethane solubility color of the waste polycarbonate resin composition and the dichloromethane solubility color of the modified polycarbonate resin composition is 100 or more (for example, 100 or more and 10000 or less, 200 or more and 10000 or less, or 300 or more and 10000 or less).

[0023] <3> A method for producing a modified polycarbonate resin composition, which comprises subjecting a waste polycarbonate resin composition having a brightness index L* of 20 to 80 to solvent treatment by contacting it with a treatment solvent, to obtain a modified polycarbonate resin composition having a difference in brightness index L* before and after solvent treatment of 5 or more (for example, 5 to 50, 5 to 30, or 9 to 25).

[0024] <4> The method for producing a modified polycarbonate resin composition according to any one of the above <1> to <3>, wherein the contact time for contacting the waste polycarbonate resin composition with the treatment solvent is 1 minute or more (preferably 1 minute to 48 hours, more preferably 2 minutes to 36 hours, and further preferably 3 minutes to 24 hours).

[0025] <5> The method for producing a modified polycarbonate resin composition according to any one of the above <1> to <4>, wherein the volume ratio of the treatment solvent to the waste polycarbonate resin composition is 1 time or more (preferably 1 time or more and 100 times or less, more preferably 1.5 times or more and 90 times or less).

[0026] <6>The manufacturing method of the modified polycarbonate resin composition according to any one of <1> to <5> above, wherein the boiling point of the foregoing treatment solvent is 150 °C or lower (preferably 35 °C or higher and 150 °C or lower).

[0027] <7>The manufacturing method of the modified polycarbonate resin composition according to any one of <1> to <6> above, wherein the foregoing treatment solvent is one or more selected from the group consisting of a ketone-based solvent, an aldehyde-based solvent, an alcohol-based solvent, an ether-based solvent, an ester-based solvent, an aromatic hydrocarbon-based solvent, and a dialkyl carbonate-based solvent.

[0028] <8>The manufacturing method of the modified polycarbonate resin composition according to any one of <1>, <2>, <4> to <7> above, wherein the heat of fusion of the polycarbonate resin contained in the foregoing modified polycarbonate resin composition is 1.0 J / g or higher (for example, 1.0 to 20.0 J / g, 1.1 to 20.0 J / g, 1.3 to 20.0 J / g, or 1.5 to 20.0 J / g).

[0029] <9>The manufacturing method of the modified polycarbonate resin composition according to any one of <3> to <7> above, wherein the heat of fusion of the polycarbonate resin contained in the foregoing modified polycarbonate resin composition is 1.0 J / g or higher (for example, 1.0 to 20.0 J / g, 1.1 to 20.0 J / g, 1.3 to 20.0 J / g, or 1.5 to 20.0 J / g).

[0030] <10>The manufacturing method of the modified polycarbonate resin composition according to <8> or <9> above, wherein the difference between the heat of fusion of the polycarbonate resin contained in the foregoing waste polycarbonate resin composition and the heat of fusion of the polycarbonate resin contained in the foregoing modified polycarbonate resin composition is 0.5 J / g or higher (for example, 0.5 to 19.5 J / g, 1.0 to 19.5 J / g, or 1.2 to 19.5 J / g).

[0031] <11>The manufacturing method of the modified polycarbonate resin composition according to any one of <1> to <10> above, wherein the length of the longest side of the foregoing waste polycarbonate resin composition is 1 mm or more and 1000 mm or less.

[0032] <12>A manufacturing method of a modified polycarbonate resin composition, which obtains a modified polycarbonate resin composition having a heat of fusion of 1.0 J / g or higher (for example, 1.0 to 20.0 J / g, 1.1 to 20.0 J / g, 1.3 to 20.0 J / g, or 1.5 to 20.0 J / g) by solvent treatment in which a waste polycarbonate resin composition having a longest side length of 1 mm or more and 1000 mm or less is brought into contact with a treatment solvent.

[0033] <13>The method for manufacturing the modified polycarbonate resin composition according to the foregoing <8>, <9>, or <12>, wherein the difference between the heat of fusion of the polycarbonate resin contained in the foregoing waste polycarbonate resin composition and the heat of fusion of the polycarbonate resin contained in the foregoing modified polycarbonate resin composition is 1.0 J / g or more (for example, 1.0 to 19.5 J / g or 1.2 to 19.5 J / g).

[0034] <14>The method for manufacturing the modified polycarbonate resin composition according to any one of the foregoing <8> to <13>, wherein the foregoing treatment solvent contains an organic solvent having Hansen solubility parameters that simultaneously satisfy the following formulas (1) and (2).

[0035] [Formula 1]

[0036] Formula (1): {4×(18.8 - δd) 2 +(7.5 - δp) 2 +(5.6 - δh) 2} 0.5 >5.6

[0037] Formula (2): {4×(18.5 - δd) 2 +(10.6 - δp) 2 +(5.9 - δh) 2} 0.5 <10.1

[0038] In the above formulas (1) and (2), δd is the value of the energy derived from the intermolecular dispersion force of the Hansen solubility parameter of the organic solvent, δp is the value of the energy derived from the intermolecular polar force of the Hansen solubility parameter of the organic solvent, and δh is the value of the energy derived from the intermolecular hydrogen bond force of the Hansen solubility parameter of the organic solvent.

[0039] <15>The method for manufacturing the modified polycarbonate resin composition according to the foregoing <14>, wherein the foregoing organic solvent contains at least one or more selected from the group consisting of acetone, toluene, dimethyl carbonate, and phenol.

[0040] <16>The method for manufacturing the modified polycarbonate resin composition according to any one of the foregoing <8> to <15>, wherein the time for contacting the foregoing waste polycarbonate resin composition with the foregoing treatment solvent is 0.2 hours or more (preferably 0.2 hours to 48 hours, more preferably 0.5 hours to 36 hours, and further preferably 1 hour to 24 hours).

[0041] <17>The method for manufacturing the modified polycarbonate resin composition according to any one of the foregoing <8> to <16>, wherein the foregoing treatment solvent contains an organic solvent and water.

[0042] <18>The method for producing a modified polycarbonate resin composition according to any one of <1> to <17> above, wherein the viscosity-average molecular weight Mv of the polycarbonate resin contained in the waste polycarbonate resin composition is 16,000 or more and 35,000 or less.

[0043] <19>The method for producing a modified polycarbonate resin composition according to any one of <1> to <18> above, wherein the waste polycarbonate resin composition contains other resins.

[0044] <20>The method for producing a modified polycarbonate resin composition according to any one of <8> to <19> above, wherein a crushing treatment is performed after the solvent treatment.

[0045] <21>The method for producing a modified polycarbonate resin composition according to <20> above, wherein the size of the modified polycarbonate resin composition after the crushing treatment is a size that passes through a sieve with a nominal mesh size of 53 mm specified in JIS-Z-8801-1 (2019) and does not pass through a sieve with a nominal mesh size of 90 μm.

[0046] <22>A method for producing bisphenol, after obtaining a modified polycarbonate resin composition by the method for producing a modified polycarbonate resin composition according to any one of <1> to <21>, depolymerizing the modified polycarbonate resin composition to obtain bisphenol.

[0047] <23>The method for producing bisphenol according to <22> above, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane.

[0048] <24>A method for producing a recycled polycarbonate resin, after obtaining bisphenol by the method for producing bisphenol according to <22> or <23> above, using a bisphenol raw material containing the obtained bisphenol to produce a recycled polycarbonate resin.

[0049] <25>A method for producing a recycled polycarbonate resin composition, which has the following steps: a step of obtaining a modified polycarbonate resin composition by the method for producing a modified polycarbonate resin composition according to any one of <1> to <24> above; and a step of melting the modified polycarbonate resin composition at 200°C or higher and 400°C or lower and then granulating it to obtain a recycled polycarbonate resin composition.

[0050] <26>A polycarbonate resin composition, which contains a polycarbonate resin having a heat of fusion of 1.0 J / g or more (for example, 1.0 to 20.0 J / g, 1.1 to 20.0 J / g, 1.3 to 20.0 J / g, or 1.5 to 20.0 J / g), and the length of the largest side of the polycarbonate resin composition is 5 mm or more and 1000 mm or less.

[0051] Advantages of the Invention

[0052] According to the present invention, a modified polycarbonate resin composition suitable as a raw material for chemical recycling and material recycling can be produced from a waste polycarbonate resin composition. In addition, a method for producing bisphenol using the modified polycarbonate resin composition as a raw material and a method for producing a recycled polycarbonate resin composition using the bisphenol as a raw material can be provided. Further, a method for producing a recycled polycarbonate resin composition using the modified polycarbonate resin composition as a raw material can be provided. Detailed Description of the Invention

[0053] Embodiments of the present invention will be described in detail below. However, the description of the constituent elements described below is an example of the embodiments of the present invention, and the present invention is not limited to the following description as long as it does not exceed the gist thereof. It should be noted that when the expression "~" is used in this specification, it is used as an expression including the numerical values and physical property values before and after it.

[0054] <Method for Producing Modified Polycarbonate Resin Composition>

[0055] The present invention relates to a method for producing a modified polycarbonate resin composition (hereinafter, sometimes referred to as "the method for producing a modified polycarbonate resin composition of the present invention"). By subjecting a waste polycarbonate resin composition to solvent treatment in which it is brought into contact with a treatment solvent, the surface of the polycarbonate resin composition is dissolved in the treatment solvent to obtain a modified polycarbonate resin composition.

[0056] As in the method for producing a modified polycarbonate resin composition of the present invention, by subjecting a waste polycarbonate resin composition to solvent treatment, a substance suitable as a raw material for chemical recycling and material recycling can be produced.

[0057] (Waste Polycarbonate Resin Composition)

[0058] The raw material for the method for producing a modified polycarbonate resin composition of the present invention can be a waste polycarbonate resin composition.

[0059] The waste polycarbonate resin composition can use post-consumer materials (used polycarbonate resin compositions) or pre-consumer materials. Post-consumer materials are polycarbonate resin compositions that have been assembled into various products in the form of molded articles and used by consumers. Specifically, they are molded articles of polycarbonate resin compositions after being used for applications such as casings for electronic devices, electrical appliances, sundries, optical recording media, automotive headlamp covers, lighting lamp covers, automotive interior materials, automotive exterior materials, transport containers, building materials (roof materials for carports, sound insulation walls on highways, etc.). In addition, as pre-consumer materials, there can be cited purified resin compositions generated during polymerization or compounding, polycarbonate resin compositions with substandard product quality, etc.

[0060] From the perspective of environmental load, as the raw material waste polycarbonate resin composition, it is preferable to use post-consumer materials. As the usage time (the time of being used) of post-consumer materials, 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 degree of deterioration is small, it will still be recycled, so it is not preferable from the aspect of environmental load.

[0061] (Polycarbonate resin)

[0062] The waste polycarbonate resin composition is a single polycarbonate resin or a composition containing a polycarbonate resin. Polycarbonate resin (PC) is a polymerization composition containing a carbonate bond (-O-C(=O)-O-). The polycarbonate resin preferably contains repeating structural units of bisphenol units and carbonate units, and more preferably contains structural units represented by the general formula (I).

[0063] [Chemical formula 1]

[0064]

[0065] As R 1 ~R 4 , they are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or an aryl group. For example, there can be cited: hydrogen atom, fluoro group, chloro group, bromo group, iodo group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, tert-butoxy group, n-pentyloxy group, isopentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, n-nonyloxy group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, benzyl group, phenyl group, tolyl group, 2,6-dimethylphenyl group, etc.

[0066] As R 5 and R6 , independently of each other, is a hydrogen atom, an alkyl group, an alkoxy group or an aryl group. For example, there may be mentioned: a hydrogen 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 2-ethylhexyl group, a n-nonyl group, a n-decyl group, a n-undecyl group, a n-dodecyl 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 cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a benzyl group, a phenyl group, a tolyl group, a 2,6-dimethylphenyl group, etc.

[0067] As R 5 and R 6 , they can be bonded or crosslinked to each other between the two groups to form a cycloalkanediyl group, a fluorenylidene group (fluoren-9,9-diyl), a xanthenylidene group (xanthene-9,9-diyl), a thioxanthenylidene group (thioxanthene-9,9-diyl), etc. As the cycloalkanediyl group, for example, there may be mentioned: a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, a cyclohexanediyl group, a 3,3,5-trimethylcyclohexanediyl group, a cycloheptanediyl group, a cyclooctanediyl group, a cyclononanediyl group, a cyclodecanediyl group, a cycloundecanediyl group, a cyclododecanediyl group, etc.

[0068] In the general formula (I), n is the number of structural units. In the general formula (I), n is not particularly limited, and for example, it is 2 to 1000.

[0069] As the structural unit represented by the above general formula (I), specifically, there may be mentioned the bisphenol units and carbonate units of bisphenols 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 thereto.

[0070] Among them, the used polycarbonate resin preferably contains structural units of bisphenol units and carbonate units derived from any bisphenol selected from 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. In particular, it preferably contains structural units of bisphenol units and carbonate units derived from 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as BPA) (R in the above general formula (1)) 1 ~R 4 is a hydrogen atom and R 5 、R 6 is a methyl group, a BPA-type polycarbonate resin).

[0071] The viscosity-average molecular weight of the polycarbonate resin contained in the waste polycarbonate resin composition is preferably 16,000 to 35,000, more preferably 17,000 to 34,000, and further preferably 18,000 to 33,000.

[0072] The waste polycarbonate resin composition is not limited to a homopolymer and may contain a copolymer having two or more different structural units or may be a mixture of two or more different polycarbonate resins. It should be noted that in the case of a polycarbonate resin alone, it is sometimes simply referred to as polycarbonate.

[0073] Like copolymers with other resins and polymer alloys, the waste polycarbonate resin composition may also contain a polycarbonate resin and other resins other than the polycarbonate resin. Examples of other resins include polyesters, polyarylesters, ABS (acrylonitrile-butadiene-styrene copolymer), etc. Examples of copolymers and polymer alloys include polycarbonate / polyester copolymers, polycarbonate / polyester alloys, polycarbonate / polyarylester copolymers, polycarbonate / polyarylester alloys, polycarbonate / ABS copolymers, polycarbonate / ABS alloys, etc. When using a composition containing other resins other than the polycarbonate resin, a composition mainly composed of a polycarbonate resin can be preferably used. For example, the composition preferably contains 30% by mass or more, more preferably 35% by mass or more, and further preferably 40% by mass or more of the polycarbonate resin. In addition, the composition may contain 50% by mass or more of the polycarbonate resin.

[0074] In addition, the waste polycarbonate resin composition may contain additives such as metal films, flame retardants, light diffusing agents, colorants (pigments and / or dyes), ultraviolet absorbers, antioxidants, mold release agents, glass fillers, carbon fibers, etc. As the metal film, vapor deposition films such as aluminum vapor deposition film can be cited; coated films such as aluminum coated film. As the flame retardant, phosphorus-based flame retardants can be cited; silicone-based flame retardants; inorganic flame retardants such as metal hydroxides and metal oxides. As the light diffusing material, organic fillers such as silicone-based particles and acrylic-based particles can be cited; inorganic fillers such as titanium dioxide, aluminum oxide, zinc oxide, zinc sulfide, barium sulfate, talc, calcium carbonate, and silicon dioxide. As the colorant, inorganic pigments, organic pigments, organic dyes, etc. can be cited. Specifically, titanium oxide, carbon black, phthalocyanine-based compounds, azo-based compounds, quinacridone-based compounds, perylene-based compounds, anthraquinone-based compounds, diketopyrrolopyrrole-based compounds, etc. can be cited. As the ultraviolet absorber, organic compounds having an ultraviolet absorption ability with a molecular weight of about 200 to 1000 can be cited. For example, as the ultraviolet absorber, organic compounds having an aromatic ring and / or a heterocyclic ring can be cited. Specifically, triazine-based compounds, benzophenone-based compounds, benzotriazole-based compounds, phenyl salicylate-based compounds, phenyl benzoate-based compounds, etc. can be cited. As the antioxidant, phenolic antioxidants can be cited; phosphoric acid-based antioxidants. As the mold release agent, fatty acid esters can be cited; silicone oil of the polysiloxane type.

[0075] The shape of the waste polycarbonate resin composition is not particularly limited as long as it is of a size that can be loaded into the solvent treatment tank. However, when the ratio of the surface area occupied by the deteriorated part to the surface area of the waste polycarbonate resin composition is large, the deteriorated part can be efficiently dissolved. Therefore, the waste polycarbonate resin composition is preferably cut, crushed, etc. and divided into an appropriate size for use. For example, in the case of directly using the waste polycarbonate resin composition formed into a large-sized material without division in building materials, etc., the dissolution of the deteriorated part becomes less efficient. In addition, the size of the solvent treatment tank increases, and the cost of equipment construction increases. Therefore, it is not preferred industrially. For the foregoing reasons, the length of the largest side of the waste polycarbonate resin composition is preferably 1000 mm or less, more preferably 800 mm or less, and further preferably 500 mm or less. On the other hand, when the waste polycarbonate resin composition is too small when contacting the treatment solvent, the entire used polycarbonate resin becomes easily soluble, and it is difficult to selectively dissolve the deteriorated part. Therefore, the length of the largest side of the waste polycarbonate resin composition is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 5 mm or more. Therefore, the length of the largest side of the waste polycarbonate resin composition is preferably 1 mm to 1000 mm, more preferably 2 mm to 800 mm, and further preferably 5 mm to 500 mm.

[0076] Examples of methods for dividing the waste polycarbonate resin composition into appropriate sizes include cutting, fusing, severing, and crushing. For example, cutting using a cutting tool, fusing using gas, plasma, laser, etc. can be mentioned. In addition, as methods of crushing, there are coarse crushing to 20 cm or less using a jaw crusher or a rotary crusher, medium crushing to 1 cm or less using a rotary crusher, a cone crusher, or a mill, and pulverization to 1 mm or less using a mill. These methods can be used alone or in combination of multiple methods.

[0077] In addition, when the waste polycarbonate resin composition is a thin plastic such as a CD or a DVD, a shredder or the like can be used for cutting and supplying it to a solvent treatment tank.

[0078] The waste polycarbonate resin composition can be appropriately washed, etc. using water, steam, an acidic solution, an alkaline solution, an oxidizing liquid, a reducing liquid, etc. before solvent treatment. In addition, when the waste polycarbonate resin composition contains other resins such as a copolymer or a polymer alloy, and components other than the polycarbonate resin such as the layers on the front and back surfaces of an optical disc, the portions formed by the components other than the polycarbonate resin can be removed in advance for use.

[0079] (Treatment solvent)

[0080] The treatment solvent is not particularly limited as long as it can partially dissolve the waste polycarbonate resin composition, and organic solvents such as halogenated hydrocarbon solvents, aromatic hydrocarbon solvents, alcohol solvents, ketone solvents, nitrogen-containing solvents, ester solvents, ether solvents, aldehyde solvents, dialkyl carbonate solvents, and sulfone solvents can be used. As halogenated hydrocarbon solvents, chlorinated hydrocarbon solvents such as chloroform, dichloromethane, monochlorobenzene, and dichlorobenzene can be cited; brominated hydrocarbon solvents such as bromonaphthalene can be cited. As aromatic hydrocarbon solvents, benzene, toluene, xylene, etc. can be cited. As alcohol solvents, methanol, ethanol, propanol, phenol, cresol, xylenol, propylene glycol, etc. can be cited. As ketone solvents, acetone, methyl ethyl ketone, diisopropyl ketone, methyl isobutyl ketone, cyclohexanone, trimethylcyclohexanone, diacetone alcohol, etc. can be cited. As nitrogen-containing solvents, dimethylformamide, ethylenediamine, triethanolamine, acetonitrile, pyridine, etc. can be cited. As ester solvents, methyl acetate, ethyl acetate, butyl acetate, ethyl acetoacetate, ethyl acrylate, butyrolactone, etc. can be cited. As ether solvents, dimethyl ether, diethyl ether, ethyl methyl ether, diphenyl ether, tetrahydrofuran, dioxane, benzofuran, etc. can be cited. As aldehyde solvents, formalin, acetaldehyde, propionaldehyde, butyraldehyde, decanal, benzaldehyde, etc. can be cited. As dialkyl carbonate solvents, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, dibutyl carbonate, etc. can be cited. As sulfone solvents, dimethyl sulfoxide, etc. can be cited. They can be used alone or in combination of two or more. In addition, the treatment solvent is mainly composed of an organic solvent, but may also contain water within the range that can dissolve a part of the used polycarbonate resin.

[0081] (Contact method)

[0082] The contact between the waste polycarbonate resin composition and the treatment solvent (solvent treatment) only needs to be carried out in a manner that the waste polycarbonate resin composition is not completely dissolved, and the method is not particularly limited. As a method of bringing the waste polycarbonate resin composition into contact with the treatment solvent, for example, solution contact methods such as dipping, spraying, and atomizing (spraying), and vapor contact with the vapor of the solvent can be cited.

[0083] Among them, in order to efficiently dissolve the surface of the waste polycarbonate resin composition or increase the crystallization rate of the waste polycarbonate resin composition, the contact method preferably adopts the dipping method of immersing the waste polycarbonate resin composition in the treatment solvent. In the state where the waste polycarbonate resin composition is immersed in the treatment solvent, the treatment solvent can be stirred or left standing without stirring.

[0084] The contact temperature of the waste polycarbonate resin composition with the treatment solvent is not particularly limited within the range that does not impair the object of the present invention, preferably 1 minute to 48 hours, more preferably 2 minutes to 36 hours, and further preferably 3 minutes to 24 hours. In addition, the temperature of the treatment solvent when contacting the waste polycarbonate resin composition is not particularly limited within the range that does not impair the object of the present invention, preferably 0 to 200 °C.

[0085] The amount of the treatment solvent used in contact with the waste polycarbonate resin composition (the amount of solvent required for solvent treatment) is not particularly limited. However, when the amount of the treatment solvent used is too small, the surface dissolution of the waste polycarbonate resin composition becomes insufficient, and it is difficult to obtain the effect of improving the hue. Therefore, the volume ratio of the treatment solvent to the waste polycarbonate resin composition to be treated is preferably 1 time or more, more preferably 1.5 times or more. On the other hand, when the amount of the treatment solvent used is too large, it has no effect on the quality of the modified polycarbonate resin composition, but the dissolved part becomes more, the yield decreases, or the devices and equipment required for solvent treatment become larger. In addition, a large amount of solvent is required, so the economy deteriorates. Therefore, the volume ratio of the treatment solvent to the waste polycarbonate resin composition to be treated is preferably 100 times or less, more preferably 90 times or less. Therefore, the volume ratio of the treatment solvent to the waste polycarbonate resin composition to be treated is preferably 1 time or more and 100 times or less, more preferably 1.5 times or more and 90 times or less.

[0086] (Drying)

[0087] The modified polycarbonate resin composition obtained by solvent treatment can be used directly in a state with the treatment solvent attached, or can be dried. That is, the method for manufacturing the modified polycarbonate resin composition of the present invention can have a drying step of drying the modified polycarbonate resin composition after the solvent treatment (hereinafter sometimes referred to as "solvent treatment step") of bringing the waste polycarbonate resin composition into contact with the treatment solvent.

[0088] Drying can be carried out by general drying methods such as normal temperature drying, heat drying, reduced pressure drying, vacuum drying, and air drying. The degree of drying can be set appropriately. For example, the mass increase rate ((mass of the modified polycarbonate resin composition after solvent treatment / mass of the waste polycarbonate resin composition before solvent treatment) × 100 (%)) can be used as an index, and after drying to a mass increase rate of 120% or less, it can be used in the next step.

[0089] (Crushing)

[0090] When the obtained modified polycarbonate resin composition is large, it is preferably crushed after the solvent treatment. It should be noted that in this application, crushing means finely crushing the polycarbonate resin after the solvent treatment, and it includes the concept of pulverization. For example, in the case of depolymerizing to obtain bisphenol using the modified polycarbonate resin composition obtained by solvent treatment, the modified polycarbonate resin composition is supplied to a decomposition tank for depolymerization. Therefore, the modified polycarbonate resin composition is preferably divided into a size that is easy to supply to the decomposition tank.

[0091] It should be noted that, as described above, crushing can be carried out before the solvent treatment. That is, the method for producing the modified polycarbonate resin composition of the present invention preferably has a pre-crushing step of crushing the waste polycarbonate resin composition before the solvent treatment step and / or a post-crushing step of crushing the modified polycarbonate resin composition after the solvent treatment step.

[0092] The polycarbonate resin contained in the modified polycarbonate resin composition has the same structural unit as the polycarbonate resin contained in the raw material waste polycarbonate resin composition, for example, it contains the structural unit shown in the above formula (I). Through solvent treatment, the surface of the raw material waste polycarbonate resin composition is dissolved, and low molecular weight components and the like are removed. Therefore, the modified polycarbonate resin preferably contains the structural unit shown in the above formula (I), and n is 4 to 1000.

[0093] [First mode]

[0094] From the perspective of resource recycling, the waste polycarbonate resin composition is preferably a used polycarbonate resin composition, and more preferably a waste polycarbonate resin composition with a dichloromethane dissolution color of 110 or more. The used polycarbonate resin composition usually has surface deterioration and a larger dichloromethane dissolution color compared to the unused polycarbonate resin composition. The dichloromethane dissolution color of the used polycarbonate resin composition depends on the use environment, use time, etc., and is usually 110 or more. As described above, in the past, it has been difficult to recycle such used polycarbonate resin compositions, but by using the method of the present invention, it is possible to produce raw materials suitable for chemical recycling and material recycling. That is, the method for producing the modified polycarbonate resin composition of the present invention can be the following method for producing the modified polycarbonate resin composition (hereinafter referred to as "production method (1A)"): By subjecting a waste polycarbonate resin composition with a dichloromethane dissolution color of 110 or more to solvent treatment by contacting it with a treatment solvent, the surface of the aforementioned waste polycarbonate resin composition is dissolved in the aforementioned treatment solvent to obtain a modified polycarbonate resin composition.

[0095] The inventors etc. have found that by subjecting a waste polycarbonate resin composition typified by used polycarbonate resin to solvent treatment, it is possible to selectively dissolve and remove the deteriorated surface of the waste polycarbonate resin composition, and the hue can be greatly improved. By using the obtained modified polycarbonate resin composition as a raw material for chemical recycling, a bisphenol with good hue can be obtained in good yield. In addition, by using the obtained modified polycarbonate resin composition as a raw material for material recycling, the abnormal odor during melting can be suppressed, and a recycled polycarbonate resin composition with good hue can be obtained.

[0096] In the production method (1A), as the waste polycarbonate resin composition, a substance having a dichloromethane dissolution color of 200 or more, 300 or more, 500 or more, or 700 or more can be used. For example, a polycarbonate resin composition that has been used outdoors for a long time is likely to deteriorate, and there is a tendency for the value of the dichloromethane dissolution color to increase. The upper limit is only required to be within the measurable range and is not particularly limited, and is usually 10000 or less. Therefore, the dichloromethane dissolution color of the waste polycarbonate resin composition used in the present invention is 110 to 10000, 200 to 10000, 300 to 10000, 500 to 10000, or 700 to 10000, etc.

[0097] Here, the dichloromethane dissolution color of the waste polycarbonate resin composition is a value obtained by multiplying the measured value of the Hazen color number of a 10 mass% dichloromethane solution of the waste polycarbonate resin composition by 10. The dichloromethane dissolution color of the modified polycarbonate resin composition is a value obtained by multiplying the measured value of the Hazen color number of a 10 mass% dichloromethane solution of the modified polycarbonate resin composition by 10. Details will be described later in the examples.

[0098] In the production method (1A), from the viewpoints of economy and workability, the treatment solvent is preferably at least one selected from the group consisting of a ketone-based solvent, an aldehyde-based solvent, an alcohol-based solvent, an ether-based solvent, an ester-based solvent, an aromatic hydrocarbon-based solvent, and a dialkyl carbonate-based solvent, and more preferably at least one selected from the group consisting of a ketone-based solvent, an alcohol-based solvent, an ether-based solvent, an aromatic hydrocarbon-based solvent, and a dialkyl carbonate-based solvent. Among them, it is preferably at least one selected from the group consisting of acetone, methanol, diethyl ether, toluene, and dimethyl carbonate, more preferably at least one selected from the group consisting of acetone, methanol, diethyl ether, and dimethyl carbonate, and further preferably acetone or dimethyl carbonate.

[0099] In addition, for easy recovery and reuse, the boiling point of the treatment solvent is preferably 150°C or lower. In addition, if the boiling point is too low, the treatment solvent is likely to volatilize during treatment, so the boiling point is preferably 35°C or higher.

[0100] In the production method (1A), the contact time with the treatment solvent (the time required for solvent treatment) may be within the range where the waste polycarbonate resin composition is not completely dissolved, and can be appropriately set according to the surface deterioration degree of the waste polycarbonate resin composition, the type of treatment solvent, treatment conditions, etc. It is preferably 1 minute to 48 hours, more preferably 2 minutes to 36 hours, and still more preferably 3 minutes to 24 hours. If the contact time is too short, the deteriorated surface of the waste polycarbonate resin composition cannot be sufficiently dissolved, which may lead to poor quality of the modified polycarbonate resin composition. On the other hand, if the contact time is too long, the dissolution of the non-deteriorated part also increases, resulting in losses, so it is not preferred. For example, under high-temperature conditions and when using a solvent such as dichloromethane in which polycarbonate resin is easily dissolved, the contact time can be set to a short treatment time such as 1 minute or more, 2 minutes or more, 3 minutes or more. In addition, under low-temperature conditions and when using solvents such as acetone, methanol, diethyl ether, toluene, and dimethyl carbonate in which polycarbonate resin is not easily dissolved, the contact time can be set to a longer treatment time such as 30 minutes or more, 1 hour or more, 2 hours or more.

[0101] (Temperature)

[0102] In the production method (1A), the temperature of the treatment solvent when contacting the waste polycarbonate resin composition is not particularly limited and can be set to 5 to 200 °C, 15 to 150 °C, etc. When the temperature of the treatment solvent is too low, it takes time for the surface of the waste polycarbonate resin composition to dissolve, so it is not efficient. When it is too high, the waste polycarbonate resin composition itself dissolves, and the yield of the modified polycarbonate resin composition may decrease.

[0103] Although it also depends on the dichloromethane solubility color of the waste polycarbonate resin composition, in the production method (1A), in the solvent treatment, it is preferably to appropriately control the type of treatment solvent, contact time, temperature, etc. so that the difference between the dichloromethane solubility color of the waste polycarbonate resin composition and the dichloromethane solubility color of the modified polycarbonate resin composition is 100 or more, more preferably 200 or more, and still more preferably 300 or more. From the viewpoint of production efficiency such as the usage amount of the treatment solvent and treatment time, for example, the difference between the dichloromethane solubility color of the waste polycarbonate resin composition and the dichloromethane solubility color of the modified polycarbonate resin composition is preferably 100 or more and 10000 or less, more preferably 200 or more and 9000 or less, or still more preferably 300 or more and 8000 or less.

[0104] The reduction rate of the dichloromethane solubility color of the waste polycarbonate resin composition ({(1 - (dichloromethane solubility color of the modified polycarbonate resin composition / dichloromethane solubility color of the waste polycarbonate resin composition)) × 100(%)}) is preferably 35% or more. In addition, the smaller the dichloromethane solubility color of the modified polycarbonate resin composition, the easier it is to obtain bisphenol with good hue through chemical recycling. Therefore, the reduction rate of the dichloromethane solubility color of the waste polycarbonate resin composition is more preferably larger in the order of 45% or more, 55% or more, 65% or more, 75% or more.

[0105] The modified polycarbonate resin composition obtained in the production method (1A) can be used directly in a state where the treatment solvent is attached, or can be dried. In addition, it can be appropriately crushed to form a crushed product.

[0106] (Modified polycarbonate resin composition)

[0107] In the production method (1A), the obtained modified polycarbonate resin composition is preferably a polycarbonate resin composition having a dichloromethane solubility color smaller than that of the waste polycarbonate resin composition, and the length of its largest side is 5 mm or more and 1000 mm or less.

[0108] [Second mode]

[0109] The production method of the modified polycarbonate resin composition of the present invention can use the brightness index L* as an index of hue. That is, the production method of the modified polycarbonate resin composition of the present invention can be the following production method of the modified polycarbonate resin composition (hereinafter referred to as "production method (2B)"): a modified polycarbonate resin composition having a difference in brightness index L* before and after solvent treatment of 5 or more is obtained by subjecting a waste polycarbonate resin composition having a brightness index L* of 20 to 80 to solvent treatment by contacting it with a treatment solvent.

[0110] By adopting the production method (2B), when the surface of the waste polycarbonate resin composition is dissolved by solvent treatment, the deteriorated surface of the waste polycarbonate resin composition can be selectively dissolved and removed, improving the hue. By using the obtained modified polycarbonate resin composition as a raw material for chemical recycling, bisphenol with good hue can be obtained with good yield. In addition, by using the obtained modified polycarbonate resin composition as a raw material for material recycling, the abnormal odor during melting can be suppressed, and a regenerated polycarbonate resin composition with good hue can be obtained.

[0111] The brightness index L* of the waste polycarbonate resin composition used in the production method (2B) is 20 to 80, and can be 25 to 75, 25 to 70. For example, a waste polycarbonate resin composition containing a colorant and having a brightness index L* of 20 to 80 is one of the preferred raw materials for the production method (2B).

[0112] It should be noted that the brightness index L* is a value measured by the reflection method using a color difference meter. The details will be described later in the examples.

[0113] The treatment solvent in the production method (2B), the contact time with the treatment solvent, and the temperature of the treatment solvent when contacting with the waste polycarbonate resin composition are the same as those in the production method (1A), and the preferred modes are also the same.

[0114] In the production method (2B), the type, contact time, temperature, etc. of the treatment solvent are appropriately controlled, and the solvent treatment is carried out in such a way that the difference in the brightness index L* between the waste polycarbonate resin composition and the modified polycarbonate resin composition (brightness difference ΔL*) is 5 or more.

[0115] From the viewpoint of yield, in the production method (2B), it is preferred to carry out the solvent treatment in such a way that the brightness difference ΔL* becomes 5 to 50, more preferably in such a way that it becomes 5 to 30, and further preferably in such a way that it becomes 9 to 25. If the brightness index L* of the waste polycarbonate resin composition is set as L1 and the brightness index L* of the modified polycarbonate resin composition is set as L2, then it is preferred that L1 + 5 ≤ L2 ≤ L1 + 50, more preferably L1 + 5 ≤ L2 ≤ L1 + 30, and further preferably L1 + 9 ≤ L2 ≤ L1 + 25.

[0116] The modified polycarbonate resin composition obtained in the production method (2B) has a brightness index L* larger than that of the waste polycarbonate resin composition. Specifically, the brightness index L* of the modified polycarbonate resin composition obtained in the production method (2B) is 25 to 90, 30 to 85, 50 to 80, etc.

[0117] The modified polycarbonate resin composition obtained in the production method (2B) can be used directly in the state with the treatment solvent attached, or can be dried. In addition, it can be appropriately crushed to form crushed materials.

[0118] (Modified polycarbonate resin composition)

[0119] In the production method (2B), the obtained modified polycarbonate resin composition preferably has a brightness index L* larger than that of the waste polycarbonate resin composition by 5 or more, and the length of its maximum side is 5 mm or more and 1000 mm or less.

[0120] [Third mode]

[0121] From the perspective of crushability, when the surface of the waste polycarbonate resin composition is dissolved by solvent treatment, it is preferable to crystallize at least a part of the polycarbonate resin to obtain a modified polycarbonate resin composition containing a polycarbonate resin having a heat of fusion of 1.0 J / g or more. Since the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is 1.0 J / g or more, the modified polycarbonate resin composition can be easily crushed. Furthermore, bisphenol and a recycled polycarbonate resin composition can be obtained with good yield using the resulting crushed product.

[0122] The film formed from the polycarbonate resin composition and the molding thickness of the optical recording disk are about 1 mm, which is relatively thin, so it can be shredded by a general shredder. On the other hand, in applications such as building materials and the headlight lenses of automobiles that require high durability and impact resistance, the molding thickness is increased to 2 mm or more, and the shapes are also diverse, so it is sometimes difficult to crush to the desired size using a general crushing device. In order to recycle the waste polycarbonate resin composition as a resource, it is necessary to put it into devices such as a molding machine and a decomposition reaction tank. At this time, it is easy to think that if the size of the waste polycarbonate resin composition is too large, it cannot enter or is difficult to enter the inlet, etc., and the operability deteriorates. Regarding such problems related to crushability, the present inventors have found that by crystallizing the polycarbonate resin to a certain extent and giving it a specific heat of fusion, crushing can be easily performed. It has also been found that although the polycarbonate resin is an amorphous resin that generally does not have a heat of fusion, by bringing the polycarbonate resin into contact with a treatment solvent such as acetone, at least a part of the polycarbonate resin can be crystallized. Here, having a heat of fusion is synonymous with a part and / or the whole of the polycarbonate resin having crystallized. The modified polycarbonate resin composition containing at least a part of the crystallized polycarbonate resin is easily crushed.

[0123] From the above, in the manufacturing method of obtaining a modified polycarbonate resin composition containing a polycarbonate resin having a heat of fusion of 1.0 J / g or more, the molded body of the waste polycarbonate resin composition having a thick-walled portion is one of the preferred raw materials. Specifically, a molded body having a portion with a thickness of 2 mm or more (for example, 2 mm to 20 mm, 3 mm to 15 mm) can be used as a suitable raw material. Examples of such a molded body include automotive headlight covers, lighting lamp covers, building materials (roof materials for carports, sound insulation walls on highways, etc.).

[0124] It should be noted that as a raw material for the manufacturing method of a modified polycarbonate resin composition containing a polycarbonate resin having a heat of fusion of 1.0 J / g or more, a molded article with a thin thickness can be used. By forming a modified polycarbonate resin composition containing a polycarbonate resin having a heat of fusion of 1.0 J / g or more, a part of the polycarbonate resin crystallizes and becomes easily broken. Therefore, even when applied to a thin molded article such as an optical recording medium that is easily broken, the life of a cutting machine and a crusher can be extended.

[0125] In addition, in the manufacturing method of a modified polycarbonate resin composition containing a polycarbonate resin having a heat of fusion of 1.0 J / g or more, as a raw material, a waste polycarbonate resin composition with a maximum side length of 1 mm to 1000 mm, a waste polycarbonate resin composition with a maximum side length of 5 mm to 1000 mm, a waste polycarbonate resin composition with a maximum side length of 10 mm to 1000 mm, a waste polycarbonate resin composition with a maximum side length of 50 mm to 1000 mm, a waste polycarbonate resin composition with a maximum side length of 100 mm to 1000 mm, etc. can be used.

[0126] That is, the manufacturing method of the modified polycarbonate resin of the present invention is preferably the following manufacturing method (hereinafter referred to as "manufacturing method (3A)"): By subjecting a waste polycarbonate resin composition having a color of 110 or more (for example, 110 or more and 10000 or less, 200 or more and 10000 or less, 300 or more and 10000 or less, 500 or more and 10000 or less, or 700 or more and 10000 or less) to solvent treatment by contacting it with a treatment solvent, the surface of the waste polycarbonate resin composition is dissolved in the treatment solvent to obtain a modified polycarbonate resin composition containing a polycarbonate resin having a heat of fusion of 1.0 J / g or more.

[0127] In addition, the manufacturing method of the modified polycarbonate resin of the present invention is preferably the following manufacturing method (hereinafter referred to as "manufacturing method (3B)"): By subjecting a waste polycarbonate resin composition having a brightness index L* of 20 to 80 (for example, 20 to 80, 25 to 75, or 25 to 70) to solvent treatment by contacting it with a treatment solvent, a modified polycarbonate resin composition containing a polycarbonate resin having a difference in brightness index L* before and after solvent treatment of 5 or more and a heat of fusion of 1.0 J / g or more is obtained.

[0128] In addition, the method for manufacturing the modified polycarbonate resin of the present invention may be the following method for manufacturing a modified polycarbonate resin composition (hereinafter referred to as "manufacturing method (3C)"): A modified polycarbonate resin composition is obtained by subjecting a waste polycarbonate resin composition having a maximum side length of 1 mm or more and 1000 mm or less to solvent treatment by contacting it with a treatment solvent, and the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is 1.0 J / g or more.

[0129] (Treatment solvent)

[0130] In manufacturing method (3A), manufacturing method (3B), and manufacturing method (3C), the treatment solvent only needs to be able to crystallize a part of the polycarbonate resin, and an organic solvent alone may be used, or it may contain an organic solvent and water. The treatment solvent preferably contains an organic solvent that swells the polycarbonate resin. The state in which the polycarbonate resin swells can be said to be a state in which a part of the polycarbonate resin is crystallized and the treatment solvent is retained in its crystal structure. The organic solvent that swells the polycarbonate resin can be indexed by the Hansen solubility parameter of the organic solvent.

[0131] The Hansen solubility parameter is calculated theoretically as a numerical constant and is a useful tool for predicting the ability of a solvent material to dissolve a specific solute.

[0132] The Hansen solubility parameter is represented by three parameters δd, δp, and δh induced experimentally and theoretically. δd is the value of the energy derived from the intermolecular dispersion force, δp is the value of the energy derived from the intermolecular polar force, and δh is the value of the energy derived from the intermolecular hydrogen bond force. By combining these three parameters (i.e., δd, δp, and δh), it can be used as a scale of solvent selectivity. The unit of the Hansen solubility parameter is given in MPa 1 / 2 or (J / cc) 1 / 2 Given.

[0133] These three parameters (i.e., δd, δp, and δh) are plotted as coordinates related to points within a three-dimensional space also known as the Hansen space.

[0134] Within this three-dimensional space (Hansen space), the closer two molecules are, the higher the likelihood of mutual solubility. To evaluate whether two molecules (molecule (1) and (2)) are close within the Hansen space, the interaction distance (Ra) between the Hansen solubility parameters is determined. Ra is calculated by the following formula.

[0135] [Equation 2]

[0136] (Ra) 2 = 4(δ d2 - δ d1 ) 2 +(δ p2 - δ p1) 2 +(δ h2 -δ h1 ) 2

[0137] In the above formula, δd1, δμ1 and δh1 respectively represent δd, δp and δh of the molecule (1). δd2, δp2 and δh2 respectively represent δd, δp and δh of the molecule (2).

[0138] That is, the mutual distance Ra between the Hansen solubility parameter of the organic solvent and the Hansen solubility parameter of the polycarbonate resin can be calculated by the following formula.

[0139] [Equation 3]

[0140] (Ra) 2 =4(δ dp -δ ds ) 2 +(δ pp -δ ps ) 2 +(δ hp -δ hs ) 2

[0141] In the above formula, δdp, δpp and δhp respectively represent δd, δp and δh of the polycarbonate resin. δds, δps and δhs respectively represent δd, δp and δh of the organic solvent.

[0142] The Hansen solubility parameter can be calculated, for example, from the solubility parameter and the specified parameters of the cohesion characteristics described by Charles Hansen in “Hansen Solubility Parameters: A User’s Handbook” by Charles M. Hansen, CRC Press (2007) and “The CRC Handbook and Solubility Parameters and Cohesion Parameters” edited by Allan F. M. Barton (1999) (1999).

[0143] For the value of the Hansen solubility parameter of a compound not recorded in the aforementioned literature, a computer software (Hansen Solubility Parameters in Practice, HSPiP) can be used for estimation.

[0144] When the organic solvent is a mixed solvent containing two or more organic solvents, the Hansen solubility parameter can be calculated in the form of the Hansen solubility parameter of the mixed solvent. The Hansen solubility parameter of the mixed solvent can use the types and mixing ratios (mole ratios) of the respective solvents as input data and be calculated using Hansen Solubility Parameter in Practice (HSPiP; Charles M. Hansen) version 5.3.02.

[0145] The interaction distance Ra can also be calculated using the software exemplified above.

[0146] In the present invention, for compounds registered in the database of computer software (Hansen Solubility Parameters in Practice (HSPiP) Ver. 5.3.02), their values are used, and for compounds not in the database, values estimated by HSPiP Ver. 5.3.02 are used.

[0147] In addition, for a solvent that dissolves a target solute, when the three parameters (δd, δp, and δh) of the solvent are plotted in Hansen space, the plotted points gather in a space close to each other, forming a sphere called the Hansen solubility sphere. The Hansen solubility sphere is a sphere in which the plotted points of the three parameters of the solvent that dissolves the target solute (good solvent) are inside the sphere, and the plotted points of the three parameters of the solvent that does not dissolve the target solute (poor solvent) are outside the sphere. The Hansen solubility parameter of the target solute is defined as the center of the Hansen solubility sphere, and the radius of the sphere is called the interaction radius (R0). By performing dissolution experiments on test pieces using various solvents, determining good solvents that dissolve the target solute, and analyzing the Hansen solubility sphere containing the good solvent group, the Hansen solubility parameter of the target solute can be obtained.

[0148] In production methods (3A), (3B), and (3C), in addition to the Hansen solubility sphere (dissolution sphere T) of the solvent group (good solvent group) that completely dissolves the polycarbonate resin, the sphere (sphere S) of the solvent group that dissolves and causes cloudiness and swelling of the polycarbonate resin is also analyzed as an index for a more suitable organic solvent.

[0149] Specifically, the test piece dissolution experiment is carried out according to the following steps.

[0150] (Step 1) At room temperature, 0.02 g of polycarbonate resin is added to 4 g of an organic solvent to prepare a sample.

[0151] (Step 2) Ultrasonic stirring is carried out for 5 minutes.

[0152] (Step 3) The sample is quickly left standing in a thermostatic bath set at 25°C for 24 hours.

[0153] (Step 4) Observe the condition of the resin after 24 hours, and determine whether it is dissolved (completely dissolved), turbid and swollen, or unchanged.

[0154] (Step 5) Based on the molecular structural formula and appearance determination result of the liquid sample, analyze using computer software (Hansen Solubility Parameters in Practice (HSPiP)) version 5.3.02.

[0155] Most of the polycarbonate resins contained in the post-consumer material and pre-consumer material recycled waste polycarbonate resin composition have bisphenol units derived from bisphenol A in the structural unit. Therefore, the treatment solvent is preferably a solvent that swells general BPA-type polycarbonate resins mainly made of bisphenol A.

[0156] When conducting a dissolution experiment on a test piece using a BPA-type polycarbonate resin, the center coordinate T point (δdpt, δppt, δhpt) of the dissolution sphere T obtained by Hansen dissolution sphere analysis of the distribution state of the solvent group (good solvent group) that completely dissolves the test piece after the test in the three-dimensional space represented by δd, δp, and δh is (18.8, 7.5, 5.6), and the radius (interaction radius) of the dissolution sphere T is 5.6. Therefore, it is inferred that when the distance T between the Hansen solubility parameter value of a certain solvent and the center coordinate T point of the dissolution sphere T is less than or equal to the radius of the dissolution sphere T, the solvent dissolves the polycarbonate resin, and when the distance T is longer than the radius of the dissolution sphere T, the solvent does not dissolve the polycarbonate resin. If the Hansen solubility parameter of the solvent is set as (δd, δp, δh), the distance T is calculated by the following formula (1a). Therefore, it is speculated that a solvent having Hansen solubility parameters (δd, δp, δh) that satisfy the following formula (1) will not completely dissolve the polycarbonate resin.

[0157] [Equation 4]

[0158] Formula (1a): Distance T = {4 × (18.8 - δd) 2 + (7.5 - δp) 2 + (5.6 - δh) 2} 0.5

[0159] [Equation 5]

[0160] Formula (1): {4 × (18.8 - δd) 2 + (7.5 - δp) 2 + (5.6 - δh) 2} 0.5 > 5.6

[0161] In addition, when conducting a dissolution experiment on a test piece made of a BPA-type polycarbonate resin, the center coordinate S point (δdps, 8pps, δhps) of the sphere S obtained by performing Hansen solubility sphere analysis on the distribution state of the solvent group that caused dissolution or cloudy swelling of the test piece after the test in the three-dimensional space shown by δd, δp, and δh was (18.5, 10.6, 5.9), and the interaction radius of the sphere S was 10.1. Therefore, it is inferred that when the distance S between the Hansen solubility parameter value of a certain solvent and the center coordinate S point of the sphere S is less than the radius of the sphere S, the solvent dissolves or causes cloudy swelling of the polycarbonate resin, and when the distance S is greater than or equal to the radius of the sphere S, the solvent neither dissolves nor causes swelling of the polycarbonate resin. If the Hansen solubility parameter of the solvent is set as (δd, δp, δh), the distance S is calculated by the following formula (2a). Therefore, it is speculated that a solvent having a Hansen solubility parameter (δd, δp, δh) that satisfies the following formula (2) dissolves or swells the polycarbonate resin.

[0162] [Equation 6]

[0163] Formula (2a): Distance S = {4×(18.5 - δd) 2 +(10.6 - δp) 2 +(5.9 - δh) 2} 0.5

[0164] [Equation 7]

[0165] Formula (2): (4×(18.5 - δd) 2 +(10.6 - δp) 2 +(5.9 - δh) 2} 0.5 <10.1

[0166] From the above, it can be seen that in the manufacturing methods (3A), (3B), and (3C), the treatment solvent preferably contains an organic solvent (hereinafter referred to as "swelling solvent") having a Hansen solubility parameter (δd, δp, δh) that simultaneously satisfies the above formulas (1) and (2). That is, it preferably contains an organic solvent (swelling solvent) in which the distance T calculated by the above formula (1a) exceeds 5.6 and the distance S calculated by the above formula (2a) is less than 10.1.

[0167] When the Hansen solubility parameter of the organic solvent does not satisfy formula (1) (that is, when the distance T is 5.6 or less), it will dissolve the polycarbonate resin, and it is difficult to obtain a crystallized polycarbonate resin. In addition, when the Hansen solubility parameter of the organic solvent does not satisfy formula (2) (that is, when the distance S is 10.1 or more), the crystallization rate of the polycarbonate resin is very slow and the efficiency is not high.

[0168] Although it also depends on the contact time between the polycarbonate resin and the treatment solvent, etc., in order to further suppress the dissolution of the polycarbonate resin and crystallize it, it is more preferable to use a treatment solvent containing an organic solvent with a distance T exceeding 7.0 and a distance S less than 10.1.

[0169] In the production methods (3A), (3B), and (3C), the treatment solvent may contain water, etc., but it is preferable to contain 70% by mass or more of a swelling solvent in the treatment solvent, and more preferably 80% by mass or more. If the content of the swelling solvent is too small, it is difficult to crystallize the polycarbonate resin, or the rate of crystallizing the polycarbonate resin becomes very slow and the efficiency is not high.

[0170] As organic solvents having Hansen solubility parameters satisfying formula (1) and formula (2), specifically, methyl ethyl ketone, methyl isobutyl ketone, acetone, butyrolactone, dimethylformamide, methyl acetate, ethyl acetate, butyl acetate, propylene glycol, dimethyl sulfoxide, dimethyl carbonate, diacetone alcohol, bromonaphthalene, acetonitrile, toluene, phenol, etc. can be mentioned.

[0171] Among them, from the viewpoints of being inexpensive and being industrially available in large quantities, at least one or more selected from the group consisting of acetone, toluene, dimethyl carbonate, and phenol are particularly preferable.

[0172] It should be noted that as organic solvents having Hansen solubility parameters that do not satisfy formula (1) but satisfy formula (2), dichloromethane, pyridine, cyclohexanone, dioxane, etc. can be mentioned. They easily completely dissolve the polycarbonate resin, so in order to obtain a crystallized polycarbonate resin, the time and temperature need to be strictly controlled. In addition, as organic solvents having Hansen solubility parameters that satisfy formula (1) but do not satisfy formula (2), methanol, ethanol, butanol, cyclohexane, etc. can be mentioned. Since they take a long time to crystallize the polycarbonate resin, the efficiency is not high.

[0173] Although it varies depending on the thickness and shape of the polycarbonate resin, in the production methods (3A), (3B), and (3C), if the contact time is short, the polycarbonate resin cannot be sufficiently crystallized and it is difficult to break. Therefore, in order to obtain a modified polycarbonate resin composition containing a polycarbonate resin with a heat of fusion of 1.0 J / g or more, the contact time with the treatment solvent is preferably 0.2 hours or more, more preferably 0.5 hours or more, and further preferably 1 hour or more. On the other hand, when the contact time is long, the polycarbonate resin can be sufficiently crystallized, but the time occupied by the treatment device becomes long, so the economy deteriorates. Therefore, the contact time is preferably 48 hours or less, more preferably 36 hours or less, and further preferably 24 hours or less. Therefore, the contact time is preferably 0.2 to 48 hours, more preferably 0.5 to 36 hours, and further preferably 1 to 24 hours.

[0174] (Temperature)

[0175] In Production Method (3A), Production Method (3B), and Production Method (3C), the temperature of the treatment solvent when in contact with the polycarbonate resin can be 0 to 150°C, 5 to 120°C, etc. When the temperature of the treatment solvent is too low, the crystallization rate is slow, and it takes a long time to obtain a polycarbonate resin having a desired heat of fusion. When it is too high, the treatment solvent vaporizes, and the contact between the polycarbonate resin and the treatment solvent may become insufficient.

[0176] (Heat of fusion of polycarbonate resin)

[0177] In Production Method (3A), Production Method (3B), and Production Method (3C), in order to facilitate crushing more easily, the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition after solvent treatment is preferably 1.1 J / g or more, more preferably 1.3 J / g or more, and further preferably 1.5 J / g or more. For example, the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is preferably 1.0 to 20.0 J / g, 1.1 to 20.0 J / g, 1.3 to 20.0 J / g, or 1.5 to 20.0 J / g.

[0178] In Production Method (3A), Production Method (3B), and Production Method (3C), it is preferable to perform solvent treatment such that the difference between the heat of fusion of the polycarbonate resin contained in the waste polycarbonate resin composition and the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is 0.5 J / g or more. The difference between the heat of fusion of the polycarbonate resin contained in the waste polycarbonate resin composition and the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is more preferably 1.0 J / g or more, and further preferably 1.2 J / g or more. For example, the difference in the aforementioned heat of fusion is preferably 0.5 to 19.5 J / g, 1.0 to 19.5 J / g, or 1.2 to 19.5 J / g.

[0179] The heat of fusion of the polycarbonate resin can be calculated from the endothermic peak of the DSC curve measured by using a differential scanning calorimeter (DSC) according to the method of JIS-K-7122 (2012). Specifically, it is the heat of fusion obtained from the area of the endothermic peak of the DSC curve measured by using a differential scanning calorimeter at a heating rate of 20°C / minute from 50°C to 400°C according to the method of JIS-K7121 (2012). Regarding the measurement sample (6 to 8 mg), a part of the polycarbonate resin composition after dissolution treatment is cut so as to avoid deviation caused by the penetration degree of the treatment solvent, and the entire thickness direction of the cut surface is shaved in a manner that includes not only the surface layer part but also the inside, and precisely weighed for preparation.

[0180] In addition, since the degree of crystallization of the polycarbonate resin before and after crushing is the same, the degree of crystallization of the polycarbonate resin in the modified polycarbonate resin composition can be confirmed by determining the heat of fusion of the crushed product of the modified polycarbonate resin composition after the crushing treatment.

[0181] (Brightness difference of the modified polycarbonate resin composition)

[0182] In addition, in the case of obtaining a modified polycarbonate resin composition containing a polycarbonate resin having a heat of fusion of 1.0 J / g or more, it is preferable to perform the solvent treatment in such a manner that the brightness L* of the obtained modified polycarbonate resin composition is greater than the brightness L* of the waste polycarbonate resin composition of the raw material. The brightness difference (ΔL*) between the waste polycarbonate resin composition of the raw material and the obtained modified polycarbonate resin composition depends on the brightness L* of the waste polycarbonate resin composition of the raw material and can be 5 to 30, 9 to 25, etc.

[0183] (Drying)

[0184] The modified polycarbonate resin composition obtained by the solvent treatment can be used directly in a state where the treatment solvent is attached, or can be dried.

[0185] In the production methods (3A), (3B) and (3C), the obtained modified polycarbonate resin composition is a polycarbonate resin composition containing a polycarbonate resin having a heat of fusion of 1.0 J / g or more, and can be made into a polycarbonate resin composition having a maximum side length of 5 mm or more and 1000 mm or less (preferably 5 mm or more and 900 mm or less, more preferably 5 mm or more and 800 mm or less).

[0186] The dichloromethane-soluble color of the modified polycarbonate resin composition obtained by the production method 3A is less than the dichloromethane-soluble color of the waste polycarbonate resin composition, and the heat of fusion is 1.0 J / g or more. In the production method 3A, the solvent treatment is preferably performed in such a manner that the difference between the dichloromethane-soluble color of the waste polycarbonate resin composition and the dichloromethane-soluble color of the modified polycarbonate resin composition becomes 100 to 10000, more preferably 200 to 9000, and further preferably 300 to 8000.

[0187] The brightness index L* of the modified polycarbonate resin composition obtained by production method 3B is greater than the brightness index L* of the waste polycarbonate resin composition, and the heat of fusion is 1.0 J / g or more. In production method 3B, the solvent treatment is preferably carried out such that the difference between the brightness index L* of the waste polycarbonate resin composition and the brightness index L* of the modified polycarbonate resin composition is 5 to 50, more preferably such that it is 5 to 30, and still more preferably such that it is 9 to 25.

[0188] (Crushing)

[0189] In production methods (3A), (3B), and (3C), a crushing treatment is preferably carried out after the solvent treatment. The size of the crushed modified polycarbonate resin composition (hereinafter, sometimes also referred to as "the crushed product of the modified polycarbonate resin composition") can be appropriately set according to the use of the obtained crushed product. It is preferably crushed to a size such that the crushed product of the aforementioned polycarbonate resin passes through a sieve with a nominal mesh (auxiliary dimension) of 53 mm specified in JIS-Z-8801-1 (2019), more preferably crushed to a size passing through a sieve with a nominal mesh of 22.4 mm, and still more preferably crushed to a size passing through a sieve with a nominal mesh of 11.2 mm. For example, in the case of using the obtained crushed product for the production of bisphenol described later, if the crushed product is too large, there is a tendency that it is difficult to be charged into the decomposition tank or the reaction efficiency decreases. On the other hand, when the crushed product is too small, there is a possibility that it will fly in the form of dust, so it is preferably crushed to a size that cannot pass through a sieve with a nominal mesh of 90 μm, and more preferably crushed to a size that cannot pass through a sieve with a nominal mesh of 500 μm.

[0190] The temperature during crushing is preferably in a temperature range where the physical properties of the polycarbonate resin have reached stability, so it is preferably -100 to 125 °C, and still more preferably 0 to 80 °C.

[0191] By the production method of the modified polycarbonate resin composition of the present invention, it is also possible to obtain a crushed product of a modified polycarbonate resin composition containing a polycarbonate resin with a heat of fusion of 1.0 J / g or more.

[0192] The crushed product of the modified polycarbonate resin composition contains a polycarbonate resin in which part or all of it has crystallized. The polycarbonate resin contained in the crushed product of the modified polycarbonate resin composition has the same structural unit as the polycarbonate resin contained in the raw material waste polycarbonate resin composition, for example, contains the structural unit represented by the above formula (I). It should be noted that by the solvent treatment, sometimes low molecular weight components in the raw material polycarbonate resin are removed. For example, the crushed product of the polycarbonate resin sometimes contains the structural unit represented by the above formula (I), and n is 4 to 1000.

[0193] The heat of fusion of the crushed product of the modified polycarbonate resin composition can be calculated from the endothermic peak of the DSC curve measured by the method based on JIS-K-7122(2012) using a differential scanning calorimeter (DSC) in the same manner as described above. Specifically, it is the heat of fusion obtained from the area of the endothermic peak of the DSC curve measured using a measurement sample (6 to 8 mg) collected from the entire crushed surface of the crushed product, using a differential scanning calorimeter by the method based on JIS-K7121(2012) and heating from 50°C to 400°C at a heating rate of 20°C / minute.

[0194] The crushed product of the modified polycarbonate resin composition is preferably sized to pass through a sieve with a nominal mesh (auxiliary size) of 53 mm specified in JIS-Z-8801-1(2019) and not pass through a sieve with a nominal mesh of 90 μm, more preferably sized to pass through a sieve with a nominal mesh (auxiliary size) of 22.4 mm and not pass through a sieve with a nominal mesh of 180 μm, and even more preferably sized to pass through a sieve with a nominal mesh (auxiliary size) of 11.2 mm and not pass through a sieve with a nominal mesh of 500 μm.

[0195] <Method for producing bisphenol>

[0196] The present invention relates to a method for producing bisphenol as follows (hereinafter, sometimes referred to as "the method for producing bisphenol of the present invention"): after obtaining a modified polycarbonate resin composition by the method for producing a modified polycarbonate resin composition of the present invention, the polycarbonate resin (hereinafter, sometimes referred to as "modified polycarbonate resin") contained in the obtained modified polycarbonate resin composition is depolymerized to obtain bisphenol.

[0197] The method for producing bisphenol of the present invention may include: step A of obtaining a modified polycarbonate resin composition by the method for producing a modified polycarbonate resin composition of the present invention, step B of depolymerizing the modified polycarbonate resin to obtain a decomposition liquid containing bisphenol, and step C of recovering bisphenol from the decomposition liquid obtained in the decomposition step.

[0198] (Step A)

[0199] Step A is a step of obtaining a modified polycarbonate resin composition by the method for producing a modified polycarbonate resin composition of the present invention. After pretreating the waste polycarbonate resin composition by the method for producing a modified polycarbonate resin composition of the present invention described above, the obtained modified polycarbonate resin composition is supplied to step B, whereby bisphenol with excellent hue can be efficiently obtained by the method for producing bisphenol of the present invention. In addition, by supplying the modified polycarbonate resin composition as a crushed product to step B, the operability of charging into a decomposition tank or the like is significantly improved, and the decomposition reaction can be efficiently carried out.

[0200] (Step B)

[0201] Process B is a decomposition process in which the modified polycarbonate resin is depolymerized to obtain a decomposition liquid containing bisphenol. In Process B, the modified polycarbonate resin is chemically decomposed. Regarding the method for depolymerizing (decomposing) the modified polycarbonate resin, various methods for various products derived from the carbonate units of the obtained polycarbonate resin are known. For example, hydrolysis using water, alcoholysis using phenol, alcoholysis using an alcohol, ammonolysis using an amine, etc. can be cited. Regardless of which decomposition method is selected, bisphenol derived from the bisphenol unit can be obtained.

[0202] Process B is preferably a process in which the modified polycarbonate resin is depolymerized in the presence of one or more selected from the group consisting of aromatic monohydric alcohols, aliphatic monohydric alcohols, and water. The aromatic monohydric alcohol, aliphatic monohydric alcohol, and water react with the modified polycarbonate resin and function as a decomposing agent for decomposing the modified polycarbonate resin into bisphenol and a C=O-containing compound derived from the carbonate unit.

[0203] Examples of the aromatic monohydric alcohol include phenol, cresol, xylenol, etc. When the aromatic monohydric alcohol functions as a decomposing agent, the modified polycarbonate resin can be decomposed into bisphenol and diaryl carbonate.

[0204] Examples of the aliphatic monohydric alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, etc. The aliphatic monohydric alcohol is preferably an alcohol having 1 to 5 carbon atoms, and more preferably any one selected from the group consisting of methanol, ethanol, and butanol. When the aliphatic monohydric alcohol functions as a decomposing agent, the modified polycarbonate resin can be decomposed into bisphenol and dialkyl carbonate.

[0205] When water functions as a decomposing agent, the modified polycarbonate resin can be decomposed into bisphenol and carbon dioxide.

[0206] In addition, a solvent is preferably used in the depolymerization. The solvent is not particularly limited as long as it can dissolve the modified polycarbonate resin, but in view of recycling, a solvent having a boiling point of 200 °C or lower is preferably used. In addition, from the viewpoint of not causing an undesired reaction, a stable solvent having low reactivity such as an aromatic hydrocarbon is preferably used. In addition, the aromatic monohydric alcohol and aliphatic monohydric alcohol not only function as a decomposing agent but also function as a solvent, and therefore can be supplied in an amount in excess of the amount as a decomposing agent, as a decomposing agent and a solvent.

[0207] Specifically, as the solvent, aromatic hydrocarbons such as benzene, toluene, and xylene can be cited; aromatic monohydric alcohols such as phenol, cresol, and xylenol; halogen-based solvents such as dichloromethane; dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate, etc. Among them, depolymerization is preferably carried out in the presence of an aromatic monohydric alcohol or a dialkyl carbonate.

[0208] When a solvent is used during depolymerization, depolymerization can be carried out after preparing a reaction solution in which the modified polycarbonate resin is completely dissolved in the solvent, or can be carried out while dissolving the modified polycarbonate resin in the solvent after preparing a slurry-like reaction solution in which a part of the modified polycarbonate resin is dissolved in the solvent. It should be noted that depolymerization can also be carried out in parallel with the preparation of the reaction solution.

[0209] The reaction solution prepared at the start of Step B is preferably a slurry-like reaction solution in which the modified polycarbonate resin is dispersed in the solvent. Even if the prepared reaction solution is in a slurry state, as depolymerization proceeds, the modified polycarbonate resin will dissolve, so at the end of Step B, a uniform (not slurry-like) decomposition solution can be obtained.

[0210] It should be noted that the modified polycarbonate resin composition sometimes also contains other resins and additives other than the modified polycarbonate resin. When the other resins and additives are insoluble in the solvent used in Step B, in the obtained decomposition solution, the other resins and additives remain as insoluble components, but the bisphenol generated by the decomposition of the modified polycarbonate resin is dissolved. In this case, by filtering the decomposition solution, a non-slurry-like decomposition solution containing bisphenol can be obtained.

[0211] When the mass ratio of the solvent to the modified polycarbonate resin (mass of the solvent / mass of the modified polycarbonate resin) is small, the dissolution rate of the modified polycarbonate resin decreases, so there is a tendency for the time required for the production of bisphenol to become longer. Therefore, this mass ratio is preferably 0.01 or more, more preferably 0.03 or more, and further preferably 0.05 or more. In addition, when this mass ratio is large, the volume of the solvent relative to the decomposition tank increases, and the amount of the modified polycarbonate resin that can be decomposed at one time becomes small, and there is a tendency for the kettle efficiency to deteriorate. Therefore, this mass ratio is preferably 100 or less, more preferably 70 or less, and further preferably 50 or less.

[0212] Depolymerization (decomposition) of the modified polycarbonate resin preferably uses a catalyst. The catalyst only needs to be able to promote the decomposition of the modified polycarbonate resin, and is preferably any one selected from the group consisting of alkali metal hydroxides, alkali metal carbonates, alkylamines, and acids.

[0213] Examples of the alkali metal hydroxide include sodium hydroxide and potassium hydroxide. Examples of the alkali metal carbonate include sodium carbonate, sodium hydrogencarbonate, potassium carbonate, and potassium hydrogencarbonate. Examples of the alkylamine include methylamine, ethylamine, propylamine, dimethylamine, diethylamine, and trimethylamine. Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, and organic acids such as carboxylic acid and sulfonic acid.

[0214] When the mass ratio of the catalyst to the modified polycarbonate resin (mass of the catalyst / mass of the modified polycarbonate resin) is small, the decomposition rate decreases, and thus there is a tendency for the decomposition time to become longer and the efficiency to deteriorate. Therefore, this mass ratio is preferably 0.001 or more, more preferably 0.005 or more, and still more preferably 0.01 or more. On the other hand, when this mass ratio is large, there is a tendency for the amounts of acid and base required for neutralization to increase. Therefore, this mass ratio is preferably 50 or less, more preferably 20 or less, and still more preferably 10 or less.

[0215] The decomposition temperature is not particularly limited. It can be set to an appropriate temperature according to the melting point and boiling point of the raw materials used in each decomposition method. When the temperature is too low, there is a concern that the solubility of the modified polycarbonate resin decreases and the decomposition liquid solidifies. Therefore, it is usually preferably carried out at 10°C or higher, more preferably at 20°C or higher. When the temperature is too high, the solvent, raw materials, and catalyst evaporate, and it may be difficult to carry out the decomposition. Therefore, it is preferably carried out at 200°C or lower, more preferably at 180°C or lower. In addition, the decomposition of the modified polycarbonate resin can be carried out under normal pressure or under pressure.

[0216] The reaction time can be appropriately selected according to the solubility of the modified polycarbonate resin, the reaction temperature, etc. When it is long, the generated bisphenol has a tendency to decompose. Therefore, it is preferably within 30 hours, more preferably within 25 hours, and still more preferably within 20 hours. On the other hand, when the reaction time is short, the decomposition reaction may not proceed sufficiently. Therefore, it is preferably 0.1 hour or more, more preferably 0.5 hour or more, and still more preferably 1 hour or more.

[0217] Specifically, step B is preferably set to any of the following steps.

[0218] (i) A step of depolymerizing the modified polycarbonate resin in the presence of an aromatic monohydric alcohol and a catalyst

[0219] (ii) A step of depolymerizing the modified polycarbonate resin in the presence of an aromatic monohydric alcohol, water and / or an aliphatic monohydric alcohol, and a catalyst

[0220] (iii) A step of depolymerizing the modified polycarbonate resin in the presence of a dialkyl carbonate, an aliphatic monohydric alcohol, and a catalyst

[0221] (i) In this case, an aromatic monohydric alcohol is used as a depolymerization agent and a solvent to depolymerize the modified polycarbonate resin. In (i), phenol is preferably used as the aromatic monohydric alcohol.

[0222] (ii) In this case, an aromatic monohydric alcohol is used as a solvent, and water and / or an aliphatic monohydric alcohol is used as a depolymerization agent to depolymerize the modified polycarbonate resin. In (ii), phenol is preferably used as the aromatic monohydric alcohol. In addition, as the aliphatic monohydric alcohol, an aliphatic monohydric alcohol having 1 to 5 carbon atoms is preferably used. For example, a combination of phenol with water and / or methanol is preferred.

[0223] (iii) In this case, a dialkyl carbonate is used as a solvent, and an aliphatic monohydric alcohol is used as a depolymerization agent to depolymerize the modified polycarbonate resin. The dialkyl carbonate and the aliphatic monohydric alcohol preferably have alkyl groups with the same number of carbon atoms, and more preferably have the same alkyl groups having 1 to 5 carbon atoms. For example, a combination of dimethyl carbonate and methanol is preferred.

[0224] (Step C)

[0225] Step C is a step of recovering bisphenol from the decomposition liquid obtained in the decomposition step. The recovery and purification of the obtained bisphenol can be carried out by conventional methods. For example, recovery and purification can be carried out by simple means such as crystallization and column chromatography. For example, after Step B, the catalyst and the solvent are removed, a purification organic solvent is mixed, the obtained organic phase is washed with water or brine, and then neutralization washing is carried out with ammonium chloride water as needed. Then, the washed organic phase is cooled to crystallize.

[0226] As the purification organic solvent, aromatic hydrocarbons such as toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and mesitylene, aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane, and dodecane, and aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, isopentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, ethylene glycol, diethylene glycol, and triethylene glycol can be used.

[0227] It should be noted that the depolymerization agent, catalyst, and solvent can also be removed by distillation before this crystallization and then crystallization can be carried out. In addition, when bisphenol A crystallizes in the presence of phenol, it forms a co-crystal with phenol. When depolymerizing a modified polycarbonate resin containing structural units derived from bisphenol A in the presence of phenol, in order not to form a co-crystal, phenol needs to be removed by distillation before crystallization.

[0228] (Bisphenol)

[0229] The bisphenol obtainable by the method for producing bisphenol of the present invention corresponds to the bisphenol unit of the polycarbonate resin contained in the waste polycarbonate resin composition. For example, the method for producing bisphenol of the present invention may be a method for depolymerizing a waste polycarbonate resin composition containing a polycarbonate resin having a structural unit represented by the above formula (I) to obtain a bisphenol represented by the following formula (II). Among them, the method for producing bisphenol of the present invention is preferably a method for obtaining 2,2-bis(4-hydroxyphenyl)propane as the bisphenol.

[0230] [Chemical formula 2]

[0231]

[0232] Regarding R in the general formula (II) 1 ~R 6 , it has the same meaning as R in the above formula (I) 1 ~R 6 .

[0233] [Method for producing recycled polycarbonate resin or recycled polycarbonate resin composition]

[0234] The modified polycarbonate resin composition obtained by the method for producing a modified polycarbonate resin composition of the present invention or the bisphenol obtained by the method for producing bisphenol of the present invention (hereinafter referred to as "recycled bisphenol") can be used as a raw material for recycled polycarbonate resin and / or recycled polycarbonate resin composition.

[0235] [Method for producing recycled polycarbonate resin]

[0236] The method for producing a recycled polycarbonate resin is a method for producing a recycled polycarbonate resin in which bisphenol is obtained by the method for producing bisphenol of the present invention, and then a bisphenol raw material containing the obtained bisphenol is used to produce the recycled polycarbonate resin.

[0237] The recycled polycarbonate resin obtained by the method for producing a recycled polycarbonate resin can be produced by, for example, a method in which a bisphenol raw material containing bisphenol (recycled bisphenol) obtained by the method for producing bisphenol of the present invention and a carbonic acid diester raw material such as diphenyl carbonate are subjected to a transesterification reaction in the presence of an alkali metal compound and / or an alkaline earth metal compound. It should be noted that the bisphenol raw material may use recycled bisphenol alone, or may use recycled bisphenol in combination with bisphenol obtained by a method other than the method for producing bisphenol of the present invention.

[0238] The above transesterification reaction can be carried out by appropriately selecting a known method. An example using bisphenol A and diphenyl carbonate as raw materials will be described below.

[0239] In the method for producing a recycled polycarbonate resin, diphenyl carbonate is preferably used in an amount in excess of bisphenol A. Considering that the recycled polycarbonate resin produced has few terminal hydroxyl groups and excellent thermal stability of the polymer, the amount of diphenyl carbonate used relative to the bisphenol A is preferably large. On the other hand, considering that the transesterification reaction rate is high and it is easy to produce a recycled polycarbonate resin having a desired molecular weight, it is preferably small. Thus, the amount of diphenyl carbonate used relative to 1 mol of bisphenol A is usually 1.001 mol or more, preferably 1.002 mol or more, and usually 1.3 mol or less, preferably 1.2 mol or less.

[0240] As a method for supplying the raw materials, bisphenol A and diphenyl carbonate may be supplied in a solid state, but it is preferred to melt one or both of them and supply them in a liquid state.

[0241] When producing a recycled polycarbonate resin by the transesterification reaction of diphenyl carbonate and bisphenol A, a transesterification catalyst is usually used. In the above method for producing a recycled polycarbonate resin, as the transesterification catalyst, an alkali metal compound and / or an alkaline earth metal compound is preferably used. One kind of them may be used, or two or more kinds may be used in any combination and ratio. Practically, an alkali metal compound is preferably used.

[0242] The amount of the catalyst used relative to 1 mol of bisphenol A or diphenyl carbonate is usually 0.05 μmol or more, preferably 0.08 μmol or more, more preferably 0.10 μmol or more, and usually 100 μmol or less, preferably 50 μmol or less, more preferably 20 μmol or less. By making the amount of the catalyst used within the above range, it is easy to obtain the polymerization activity required for producing a recycled polycarbonate resin having a desired molecular weight, and the polymer has excellent hue. In addition, over-branching of the polymer does not occur, and it is easy to obtain a recycled polycarbonate resin having excellent fluidity during molding.

[0243] In order to produce a recycled polycarbonate resin by the above method, it is preferred to continuously supply the above two raw materials to a raw material mixing tank, and continuously supply the obtained mixture and the transesterification catalyst to a polymerization tank.

[0244] In the production of a recycled polycarbonate resin by the transesterification method, usually, the two raw materials supplied to the raw material mixing tank are uniformly stirred and then supplied to a polymerization tank containing a catalyst to produce a polymer.

[0245] [Method for Producing a Recycled Polycarbonate Resin Composition]

[0246] The manufacturing method of the recycled polycarbonate resin composition includes: a step of obtaining a modified polycarbonate resin composition by using the manufacturing method of the modified polycarbonate resin composition of the present invention; and a step of melting the aforementioned modified polycarbonate resin composition at 200°C or higher and 400°C or lower and then granulating it to obtain the recycled polycarbonate resin composition.

[0247] After the waste polycarbonate resin composition is pretreated by the manufacturing method of the modified polycarbonate resin composition of the present invention and then melted and granulated, a recycled polycarbonate resin composition that can suppress the generation of abnormal odor during melting and has a good hue can be obtained. In addition, by using the modified polycarbonate resin composition as the crushed material, the operability is improved.

[0248] The manufacturing method of the recycled polycarbonate resin composition can use a known manufacturing method of resin particles except that the melting temperature is set at 200°C or higher and 400°C or lower. For example, by using an extruder such as a single-screw extruder or a twin-screw extruder, the modified polycarbonate resin composition is melt-kneaded, and the kneaded product is extruded from the outlet of the extruder, cooled, and then sent to a granulator and cut into an appropriate length, whereby particles of the recycled polycarbonate resin composition can be obtained. In addition, during the melt-kneading, in addition to the modified polycarbonate resin composition, components such as an unused polycarbonate resin, a recycled polycarbonate resin obtained by the manufacturing method of the recycled polycarbonate resin, other thermoplastic resins, and additives can be appropriately mixed.

[0249] The melting temperature is 200°C or higher and 400°C or lower. When the melting temperature is lower than 200°C, melting takes time, so the efficiency is poor. In addition, when the melting temperature exceeds 400°C, it may be modified due to thermal deterioration. Therefore, the melting temperature is preferably 220°C to 390°C, more preferably 240°C to 380°C.

[0250] Examples

[0251] Hereinafter, the present invention will be described in more detail by way of examples and comparative examples. However, the present invention is not limited by the following examples as long as it does not exceed its gist.

[0252] [Raw materials and reagents]

[0253] The waste polycarbonate resin composition is used for the headlight cover of an automobile or the roof material of a carport.

[0254] · Headlamp cover of a car: Use 10 kg of headlamp covers cut from the headlamps of ordinary cars manufactured from 2005 to 2010 by a disk grinder (varying according to vehicle models. The average size is 500 mm × 250 mm × 5 mm; with concavities and convexities). Each headlamp cover is divided into pieces with an average size of 200 mm × 100 mm × 5 mm by fusing and 200 g is used for weighing.

[0255] · Roof material of a carport: Use 1 piece of roof material of a carport that has been used outdoors for 3 years (600 mm × 5000 mm × 5 mm; tea-colored transparent).

[0256] Dichloromethane, acetone, methanol, diethyl ether, toluene, dimethyl carbonate, phenol, sodium bicarbonate, potassium hydroxide, sulfuric acid, dodecanethiol, acetonitrile and cesium carbonate use the reagents of FUJIFILM Wako Pure Chemical Corporation.

[0257] Diphenyl carbonate uses the product of Mitsubishi Chemical Corporation.

[0258] It should be noted that the Hansen solubility parameters of acetone, toluene, dimethyl carbonate, methanol, diethyl ether and water use the values registered in the database of the computer software (Hansen Solubility Parameters in Practice (HSPiP) version 5.3.02). The specific values are as follows:

[0259] Hansen solubility parameter of acetone (δd = 15.5, δp = 10.4, δh = 7)

[0260] Hansen solubility parameter of toluene (δd = 18.0, δp = 1.4, δh = 2.0)

[0261] Hansen solubility parameter of dimethyl carbonate (δd = 15.5, δp = 8.6, δh = 9.7)

[0262] Hansen solubility parameter of methanol (δd = 14.7, δp = 12.3, δh = 22.3)

[0263] Hansen solubility parameter of diethyl ether (δd = 14.5, δp = 2.9, δh = 4.6)

[0264] Hansen solubility parameter of water (δd = 15.5, δp = 16, δh = 42.3)

[0265] Using the Hansen solubility parameters of acetone, toluene, dimethyl carbonate, methanol, diethyl ether and water as processing solvents, calculate the distance T (the above formula (1a)) and the distance S (the above formula (2a)) for each solvent, and the results are as follows.

[0266] The Hansen solubility parameters of acetone were used to obtain the distance T and the distance S, and as a result, the distance T = 7.3 and the distance S = 6.1.

[0267] The Hansen solubility parameters of toluene were used to obtain the distance T and the distance S, and as a result, the distance T = 7.3 and the distance S = 10.0.

[0268] The Hansen solubility parameters of dimethyl carbonate were used to obtain the distance T and the distance S, and as a result, the distance T = 7.8 and the distance S = 7.4.

[0269] The Hansen solubility parameters of methanol were used to obtain the distance T and the distance S, and as a result, the distance T = 19.2 and the distance S = 18.2.

[0270] The Hansen solubility parameters of diethyl ether were used to obtain the distance T and the distance S, and as a result, the distance T = 9.8 and the distance S = 11.2.

[0271] The Hansen solubility parameters of water were used to obtain the distance T and the distance S, and as a result, the distance T = 38.2 and the distance S = 37.3.

[0272] [Evaluation of the hue of the polycarbonate resin composition]

[0273] The evaluation of the hue (color in dichloromethane solution) of the polycarbonate resin composition was carried out by the following method.

[0274] · Apparatus: SE6000 manufactured by Nippon Denshoku Industries Co., Ltd.

[0275] · Instrument: Test tube (24 mm × 200 m / m P-24) manufactured by Nippon Rika Glass Co., Ltd.

[0276] Weigh 2 g of the polycarbonate resin composition into a test tube, add 18 g of dichloromethane, and completely dissolve it. Measure the Hazen color number of the dichloromethane solution containing 10% by mass of the polycarbonate resin composition, and the value obtained by multiplying the measured value by 10 is taken as the color in dichloromethane solution of the polycarbonate resin composition. The effective number of digits of the Hazen color number is 2 digits.

[0277] [Evaluation of the hue of bisphenol]

[0278] The evaluation of the hue of bisphenol was carried out by the following method.

[0279] · Apparatus: SE6000 aluminum block heater manufactured by Nippon Denshoku Industries Co., Ltd.

[0280] · Instrument: Test tube (24 mm × 200 m / m P-24) manufactured by Nippon Rika Glass Co., Ltd.

[0281] Measure 20 g of the product bisphenol in a test tube, heat it to 175 °C and melt it using an aluminum block heater, and measure the Hazen color number at the moment 30 minutes after the start of heating. The effective number of digits of the Hazen color number is 2 digits.

[0282] [Evaluation of the Friability of Polycarbonate Resin Composition]

[0283] The friability of the polycarbonate resin composition is evaluated as follows using the following apparatus.

[0284] · Apparatus: Granulator SPCIII-C750 manufactured by HARMO Co., Ltd.

[0285] · Rotation speed of the coarse crushing knife: 37.5 rpm

[0286] · Granulating knife: 2.8 mm × 4.5 mm × 35 pieces

[0287] Evaluation: Can be crushed... 〇

[0288] Cannot be crushed with the granulating knife... △

[0289] Cannot be coarsely crushed with the coarse crushing knife... ×

[0290] [Measurement of the Size of the Friable Material of Polycarbonate Resin Composition]

[0291] The size of the friable material of the polycarbonate resin composition is evaluated using the following test sieve that meets the JIS-Z-8801-1 (2006) standard.

[0292] · Test sieve: ST system (plain weave) manufactured by Tokyo SCREEN Co., Ltd., diameter 200 mm, height 60 mm, nominal mesh size 4.75 mm, 2.8 mm

[0293] [Measurement of the Heat of Fusion of Polycarbonate Resin Composition]

[0294] The heat of fusion of the polycarbonate resin composition is measured by the following method in accordance with JIS-K-7122 (2012).

[0295] · Apparatus: DSC6220 manufactured by Seiko Instruments (SII) Inc.

[0296] · Preparation of the measurement sample (1):

[0297] Scrape the entire fractured surface of the friable material of the polycarbonate resin composition with a cutter, and accurately weigh 6 - 8 mg in a sample pan using a micro spatula.

[0298] · Preparation of the measurement sample (2):

[0299] Use pliers to break a part of the solvent-treated polycarbonate resin composition and take a sample. Use a cutter to shave the entire thickness direction of the fracture surface, and accurately weigh 6 - 8 mg in a sample dish using a micro spatula.

[0300] · Measurement conditions: Heat from 50 °C to 400 °C at a heating rate of 20 °C / min, and measure the DSC curve. Measure the heat from the area of the endothermic peak of the measured DSC curve.

[0301] [Method for measuring the brightness index L* of the crushed polycarbonate resin composition]

[0302] The brightness index L* of the crushed polycarbonate resin is carried out by the following method.

[0303] · Apparatus: SE6000 manufactured by Nippon Denshoku Industries Co., Ltd.

[0304] · Instrument: Round sample cell for measurement (diameter 30 mm)

[0305] · Measurement mode: Reflection

[0306] Weigh 5 g of the crushed polycarbonate resin in the round sample cell for measurement, and measure the brightness index L*. Measure one sample 5 times, and rotate the round sample cell about 60 degrees each time. Take the average of the 5 measurements as the brightness index L* of the crushed polycarbonate resin.

[0307] [Analysis of bisphenol A]

[0308] · Apparatus: "LC10A" manufactured by Shimadzu Corporation

[0309] Unison UK C18 3μm 250×4.6mmI.D

[0310] · Analysis temperature: 40 °C

[0311] · Composition of eluent: A 10 vol% / B 90 vol% isocratic solvent mode

[0312] Solution A: Water

[0313] Solution B: Acetonitrile

[0314] · Analysis time: 30 minutes

[0315] [Viscosity-average molecular weight (Mv)]

[0316] Regarding the viscosity-average molecular weight (Mv), dissolve the polycarbonate resin in dichloromethane (concentration 6.0 g / L), measure the specific viscosity (ηsp) at 20 °C using an Ubbelohde viscometer, and calculate the viscosity-average molecular weight (Mv) by the following formula.

[0317] ηsp / C = [η](1 + 0.28ηsp)

[0318] [η] = 1.23×10 -4 Mv 0.83

[0319] [Tone evaluation of polycarbonate resin composition molded sheet]

[0320] The tone evaluation of the polycarbonate resin composition molded sheet is to use the following small injection molding machine to produce a test piece of 25 mm × 25 mm × 3 mm from the polycarbonate resin composition and measure YI.

[0321] · Small injection molding machine: C, Mobile - 0813 pre - plunger type (manufactured by EPSON TcFORM Co., Ltd.)

[0322] · Plasticizing section temperature: 280 °C

[0323] · Injection section temperature: 310 °C

[0324] · Mold temperature: 90 °C

[0325] · Injection speed: 30 mm / sec

[0326] · Cooling time: 10 sec

[0327] · Spectrophotometric color - haze meter: COH7770 (manufactured by Nippon Denshoku Industries Co., Ltd.)

[0328] Number of measurements: Measure 3 times and calculate the average value.

[0329] [Reference Example 1]

[0330] As the waste polycarbonate resin composition, the front headlight cover of an automobile (Mv of polycarbonate resin: 25000) was used.

[0331] The front headlight cover was crushed using a granulator SPCIII - C750 manufactured by HARMO Co., Ltd. (coarse crushing knife rotation speed: 37.5 rpm, granulating knife: 2.8 mm × 4.5 mm × 35 pieces) to obtain crushed materials. It should be noted that although a part of the input was crushed, the front headlight cover bit into the coarse crushing knife during the crushing process and the device stopped and could not be chopped up.

[0332] For the materials that could be crushed, the size was measured, and the result was the size that passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm. The dichloromethane - soluble color of the crushed material of this front headlight cover (waste PC dichloromethane - soluble color) was 760. In addition, sampling was carried out using pliers in such a way as to include the entire thickness direction of the cut surface of the front headlight cover of the automobile, and DSC was measured. As a result, an endothermic peak of 0.1 J / g was observed between 200 °C and 250 °C.

[0333] <Example 1>

[0334] [Example 1-1]

[0335] (Manufacture of modified polycarbonate resin composition)

[0336] Weigh 100 g of the crushed product obtained in Reference Example 1 into a stainless steel sieve with a mesh size of 1 mm, place the sieve in a stainless steel covered container, and supply 500 g of acetone as a treatment solvent thereto. At this time, it was confirmed that the crushed product was completely immersed in acetone. After standing for 1 hour to dissolve the surface of the crushed product, lift the sieve, spread the used polycarbonate resin over a tray from which paper scraps have been removed, and air-dry it for one day and night to obtain modified polycarbonate resin A. It should be noted that the solvent treatment and drying are carried out at room temperature.

[0337] The dichloromethane dissolution color (modified PC dichloromethane dissolution color) of the modified polycarbonate resin composition A is 420.

[0338] In addition, DSC was measured, and as a result, an endothermic peak of 2.1 J / g was observed between 200 °C and 250 °C.

[0339] (Manufacture of bisphenol)

[0340] Under a nitrogen atmosphere and at room temperature, 80 g of the modified polycarbonate resin composition (since the repeating unit of the polycarbonate resin is 254 g / mol, it is 80 g ÷ 254 g / mol = 0.315 mol), 71 g of an aqueous sodium bicarbonate solution adjusted to 7% by mass, 240 g of phenol, and 1.6 g of dodecyl mercaptan were added to a jacketed separable flask equipped with a serpentine condenser, a stirring blade, and a thermometer. The reaction solution was in a slurry state.

[0341] Then, the internal temperature was raised to 90 °C, and the reaction was carried out for 4 hours while maintaining 90 °C to obtain a homogeneous solution.

[0342] A 70% aqueous sulfuric acid solution was supplied to the obtained reaction solution until the aqueous phase reached pH 7.5, and as a result, carbon dioxide gas was generated. Then, stirring was stopped for oil-water separation, and the aqueous phase was taken out from the flask to obtain 380 g of organic phase A1.

[0343] A part of the obtained organic phase A1 was subjected to composition analysis by high performance liquid chromatography, and the formation of bisphenol A was confirmed.

[0344] The obtained organic phase A1 was transferred to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator. While observing the distillate amount, the internal temperature was slowly raised to 130 °C, and the internal pressure was slowly reduced from atmospheric pressure to 10 kPa, and water and phenol were distilled off until the distillation rate (distillate ÷ organic phase A1 × 100) reached 75% by mass.

[0345] Then, the pressure in the flask was restored with nitrogen, the internal temperature was lowered to 80 °C, 270 g of toluene and 100 g of water were added to obtain organic phase A2. The obtained organic phase A2 was cooled to 10 °C to obtain a slurry. The obtained slurry was filtered to obtain 80 g of a crude filter cake.

[0346] The obtained crude filter cake was again fed under a nitrogen atmosphere into a jacketed separable flask equipped with a serpentine condenser, a stirring blade, and a thermometer, 500 g of toluene was added, and the temperature was raised to 80 °C with stirring to dissolve it, obtaining organic phase A3.

[0347] 80 g of water was fed into organic phase A3, and it was stirred for 15 minutes to wash organic phase A3. After 15 minutes, stirring was stopped, and the organic phase and the aqueous phase were separated into two phases, and the aqueous phase was removed to obtain an organic phase. This operation was repeated 3 times to obtain organic phase A4.

[0348] The obtained organic phase A4 was cooled to 10 °C to obtain a slurry. The obtained slurry was filtered to obtain 70 g of a filter cake.

[0349] The obtained filter cake was dried with a rotary evaporator to obtain 56 g of bisphenol A. The yield of bisphenol A was 78.0 mol% (56 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 78.0 mol%). The melt color (BPA melt color) of this bisphenol A was APHA 290.

[0350] [Example 1-2]

[0351] (Manufacture of modified polycarbonate resin composition)

[0352] The immersion time in acetone was changed from 1 hour to 0.5 hour, and otherwise, the same operations as in the manufacture of the modified polycarbonate resin composition of Example 1-1 were carried out to obtain a modified polycarbonate resin composition B.

[0353] The dichloromethane dissolution color of the modified polycarbonate resin composition B was 460.

[0354] In addition, DSC was measured, and as a result, an endothermic peak of 1.6 J / g was observed between 200 °C and 250 °C.

[0355] (Manufacture of bisphenol)

[0356] Changing from the modified polycarbonate resin composition A to the modified polycarbonate resin composition B, and otherwise, the same operations as in the manufacture of bisphenol in Example 1-1 were carried out to obtain 55 g of bisphenol A. The yield of bisphenol A was 76.6 mol% (55 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 76.6 mol%).

[0357] The melt color of this bisphenol A was APHA 300.

[0358] [Examples 1-3]

[0359] (Manufacture of Modified Polycarbonate Resin Composition)

[0360] The immersion time in acetone was changed from 1 hour to 3 hours, and other than that, the same operations as in the manufacture of the modified polycarbonate resin composition of Example 1-1 were carried out to obtain a modified polycarbonate resin composition C.

[0361] The dichloromethane solution color of the modified polycarbonate resin composition C was 300.

[0362] In addition, DSC was measured, and as a result, an endothermic peak of 6.3 J / g was observed between 200 °C and 250 °C.

[0363] (Manufacture of Bisphenol)

[0364] The modified polycarbonate resin composition A was changed to the modified polycarbonate resin composition C, and other than that, the same operations as in the manufacture of bisphenol in Example 1-1 were carried out to obtain 55 g of bisphenol A. The yield of bisphenol A was 76.6 mol% (55 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 76.6 mol%).

[0365] The melt color of this bisphenol A was APHA 200.

[0366] [Example 1-4]

[0367] (Manufacture of Modified Polycarbonate Resin Composition)

[0368] The treatment solvent was changed from acetone to methanol, and other than that, the same operations as in the manufacture of the modified polycarbonate resin composition of Example 1-1 were carried out to obtain a modified polycarbonate resin composition D.

[0369] The dichloromethane solution color of the modified polycarbonate resin composition D was 430.

[0370] In addition, DSC was measured, and as a result, an endothermic peak of 0.1 J / g was observed between 200 °C and 250 °C.

[0371] (Manufacture of Bisphenol)

[0372] The modified polycarbonate resin composition A was changed to the modified polycarbonate resin composition D, and other than that, the same operations as in the manufacture of bisphenol in Example 1-1 were carried out to obtain 57 g of bisphenol A. The yield of bisphenol A was 79.4 mol% (57 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 79.4 mol%).

[0373] The melt color of this bisphenol A was APHA 290.

[0374] [Examples 1 - 5]

[0375] (Manufacture of Modified Polycarbonate Resin Composition)

[0376] The processing solvent was changed from acetone to diethyl ether, and other than that, the same operations as in the manufacture of the modified polycarbonate resin composition of Example 1 - 1 were carried out to obtain a modified polycarbonate resin composition E.

[0377] The dichloromethane solubility color of the modified polycarbonate resin composition E was 400.

[0378] In addition, DSC was measured, and as a result, an endothermic peak of 0.5 J / g was observed between 200°C and 250°C.

[0379] (Manufacture of Bisphenol)

[0380] The modified polycarbonate resin composition A was changed to the modified polycarbonate resin composition E, and other than that, the same operations as in the manufacture of bisphenol in Example 1 - 1 were carried out to obtain 55 g of bisphenol A. The yield of bisphenol A was 76.6 mol% (55 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 76.6 mol%).

[0381] The melt color of this bisphenol A was APHA 260.

[0382] [Examples 1 - 6]

[0383] (Manufacture of Modified Polycarbonate Resin Composition)

[0384] The processing solvent was changed from acetone to toluene, and other than that, the same operations as in the manufacture of the modified polycarbonate resin composition of Example 1 - 2 were carried out to obtain a modified polycarbonate resin composition F.

[0385] The dichloromethane solubility color of the modified polycarbonate resin composition F was 730.

[0386] In addition, DSC was measured, and as a result, an endothermic peak of 3.1 J / g was observed between 200°C and 250°C.

[0387] (Manufacture of Bisphenol)

[0388] The modified polycarbonate resin composition A was changed to the modified polycarbonate resin composition D, and other than that, the same operations as in the manufacture of bisphenol in Example 1 - 1 were carried out to obtain 56 g of bisphenol A. The yield of bisphenol A was 78.0 mol% (56 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 78.0 mol%).

[0389] The melt color of this bisphenol A was APHA 480.

[0390] [Examples 1 - 7]

[0391] (Manufacture of Modified Polycarbonate Resin Composition)

[0392] The processing solvent was changed from acetone to toluene, and other than that, the same operations as those for the manufacture of the modified polycarbonate resin compositions of Examples 1 - 3 were carried out to obtain a modified polycarbonate resin composition G.

[0393] The dichloromethane solubility color of the modified polycarbonate resin composition G was 600.

[0394] In addition, DSC was measured, and as a result, an endothermic peak of 7.5 J / g was observed between 200 °C and 250 °C.

[0395] (Manufacture of Bisphenol)

[0396] The modified polycarbonate resin composition A was changed to the modified polycarbonate resin composition G, and other than that, the same operations as those for the manufacture of bisphenol in Example 1 - 1 were carried out to obtain 55 g of bisphenol A. The yield of bisphenol A was 76.6 mol% (55 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 76.6 mol%).

[0397] The melt color of this bisphenol A was APHA 370.

[0398] [Examples 1 - 8]

[0399] (Manufacture of Modified Polycarbonate Resin Composition)

[0400] The processing solvent was changed from acetone to dimethyl carbonate, and other than that, the same operations as those for the manufacture of the modified polycarbonate resin composition of Example 1 - 2 were carried out to obtain a modified polycarbonate resin composition H.

[0401] The dichloromethane solubility color of the modified polycarbonate resin composition H was 170.

[0402] In addition, DSC was measured, and as a result, an endothermic peak of 1.6 J / g was observed between 200 °C and 250 °C.

[0403] (Manufacture of Bisphenol)

[0404] The modified polycarbonate resin composition A was changed to the modified polycarbonate resin composition H, and other than that, the same operations as those for the manufacture of bisphenol in Example 1 - 1 were carried out to obtain 54 g of bisphenol A. The yield of bisphenol A was 75.2 mol%. (54 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 75.2 mol%).

[0405] The melt color of this bisphenol A was APHA 120.

[0406] [Examples 1 - 9]

[0407] (Manufacture of Modified Polycarbonate Resin Composition)

[0408] The processing solvent was changed from acetone to dimethyl carbonate, and other than this, the same operations as those for the manufacture of the modified polycarbonate resin compositions in Examples 1 - 3 were carried out to obtain modified polycarbonate resin composition I.

[0409] The dichloromethane solution color of modified polycarbonate resin composition I was 180.

[0410] In addition, DSC was measured, and as a result, an endothermic peak of 4.4 J / g was observed between 200 °C and 250 °C.

[0411] (Manufacture of Bisphenol)

[0412] The modified polycarbonate resin composition A was changed to modified polycarbonate resin composition I, and other than this, the same operations as those for the manufacture of bisphenol in Example 1 - 1 were carried out to obtain 54 g of bisphenol A. The yield of bisphenol A was 75.2 mol% (54 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 75.2 mol%).

[0413] The melt color of this bisphenol A was APHA 130.

[0414] [Comparative Example 1]

[0415] (Manufacture of Bisphenol)

[0416] The modified polycarbonate resin composition A was changed to the crushed product obtained in Reference Example 1, and other than this, the same operations as those for the manufacture of bisphenol in Example 1 - 1 were carried out to obtain 57 g of bisphenol A. The yield of bisphenol A was 79.4 mol% (57 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 79.4 mol%).

[0417] The melt color of this bisphenol A was APHA 500.

[0418] [Comparative Example 2]

[0419] (Manufacture of Modified Polycarbonate Resin Composition)

[0420] The processing solvent was changed from acetone to water, and other than this, the same operations as those for the manufacture of the modified polycarbonate resin compositions in Examples 1 - 3 were carried out to obtain modified polycarbonate resin composition J.

[0421] The dichloromethane solution color of modified polycarbonate resin composition J was 760.

[0422] In addition, DSC was measured, and an endothermic peak of 0.1 J / g was observed between 200 °C and 250 °C.

[0423] (Manufacture of bisphenol)

[0424] The modified polycarbonate resin composition A was changed to the modified polycarbonate resin composition J, and otherwise, the same operations as in the manufacture of bisphenol in Example 1 were carried out to obtain 56 g of bisphenol A. The yield of bisphenol A was 78.0 mol% (56 g ÷ 228 g / mol ÷ 0.315 mol × 100 = 78.0 mol%).

[0425] The melt color of this bisphenol A was APHA 490.

[0426] The results of Examples 1-1 to 1-9 and Comparative Examples 1 and 2 are summarized in Table 1. From reading Table 1, it can be seen that by subjecting the waste polycarbonate resin composition to solvent treatment, a modified polycarbonate resin composition with improved hue can be obtained. In addition, by depolymerizing the modified polycarbonate resin composition, bisphenol with good hue can be obtained.

[0427] [Table 1]

[0428]

[0429] [Example 1-10]

[0430] In a 45 mL glass reaction tank equipped with a stirrer and a distillation tube, 10.00 g (0.04 mol) of bisphenol A obtained in Example 1-2, 9.95 g (0.05 mol) of diphenyl carbonate, and 18 μL of an aqueous cesium carbonate solution at 400 mass ppm were added. The pressure in the glass reaction tank was reduced to about 100 Pa, and then restored to atmospheric pressure using nitrogen, and this operation was repeated 3 times to replace the inside of the reaction tank with nitrogen. Then, the reaction tank was immersed in an oil bath at 220 °C to dissolve the contents.

[0431] The rotation speed of the stirrer was set to 100 times per minute, and while distilling off phenol by-produced by the oligomerization reaction of bisphenol A and diphenyl carbonate in the reaction tank, the pressure in the reaction tank was reduced from 101.3 kPa to 13.3 kPa with an absolute pressure gauge over 40 minutes.

[0432] Next, the pressure in the reaction tank was maintained at 13.3 kPa, and while further distilling off phenol, a transesterification reaction was carried out for 80 minutes.

[0433] Then, the external temperature of the reaction tank was raised to 290 °C, and the pressure in the reaction tank was reduced from 13.3 kPa to 399 Pa with an absolute pressure gauge over 40 minutes, and the distilled phenol was removed from the system.

[0434] Then, the absolute pressure in the reaction tank is reduced to 30 Pa, and polycondensation reaction is carried out. When the stirrer in the reaction tank reaches a predetermined stirring power determined in advance, the polycondensation reaction is terminated. The time from heating to 290 °C to the end of polymerization is 120 minutes.

[0435] Next, after restoring the reaction tank to an absolute pressure of 101.3 kPa using nitrogen, it is pressurized to a gauge pressure of 0.2 MPa, and the polycarbonate resin is withdrawn from the reaction tank to obtain the polycarbonate resin. The viscosity-average molecular weight (Mv) of the obtained polycarbonate resin is 26,300.

[0436] [Example 1-11]

[0437] Using the modified polycarbonate resin composition C obtained in Examples 1-3 as a raw material, a test piece is produced using a small injection molding machine under the conditions described in the above [Tone Evaluation of Polycarbonate Resin Composition Molded Sheet], and YI is measured. YI is 15.6. During injection molding, the moldability is good and no abnormal odor is generated.

[0438] [Comparative Example 3]

[0439] The crushed product of the waste polycarbonate resin composition obtained in Reference Example 1 is used as a raw material, and a test piece is produced by the same method as in Examples 1-11, and YI is measured. YI is 37.5. During injection molding, although the moldability is good, a burnt smell is generated.

[0440] [Table 2]

[0441] Raw material YI Moldability Abnormal odor Examples 1-11 Modified PC 15.6 Good None Comparative Example 3 Waste PC 37、5 Good Yes

[0442] <Example 2>

[0443] [Example 2-1]

[0444] (Solvent treatment process)

[0445] Put 200 g of the headlamp cover of an automobile into a stainless steel covered tray, and add 1 L of acetone. At this time, the entire headlamp cover is in a state of being immersed in the solvent. After adding acetone, the headlamp cover is taken out at room temperature after 3 hours, and the acetone attached to the surface is dried at room temperature to obtain the solvent-treated headlamp cover A.

[0446] Take a part of the solvent-treated headlamp cover A for sampling, measure DSC, and as a result, an endothermic peak of 6.3 J / g is observed between 200 °C and 250 °C.

[0447] (Crushing process)

[0448] The headlight cover A obtained in the foregoing solvent treatment process is put into a granulator for crushing. All the input amount is crushed. The size of the crushed material is measured, and the result is a size that passes through a sieve with a nominal mesh size of 4.75 mm but does not pass through a sieve with a nominal mesh size of 2.8 mm.

[0449] The DSC of the crushed material is measured, and as a result, an endothermic peak of 6.3 J / g is observed between 200 °C and 250 °C.

[0450] In addition, the dichloromethane dissolution color of the crushed material is 300.

[0451] From the DSC results, it can be confirmed that the heat of fusion of the polycarbonate resin is the same after solvent treatment and after crushing. Therefore, in the following examples, only the heat of fusion of the crushed material is obtained.

[0452] [Example 2-2]

[0453] (Solvent treatment process)

[0454] The solvent treatment time is set to 1 hour, and except for this, the treatment is carried out in the same manner as the solvent treatment process of Example 2-1 to obtain a solvent-treated headlight cover B.

[0455] (Crushing process)

[0456] The headlight cover B obtained in the foregoing solvent treatment process is put into a granulator for crushing. All the input amount is crushed. The size of the crushed material is measured, and the result is a size that passes through a sieve with a nominal mesh size of 4.75 mm but does not pass through a sieve with a nominal mesh size of 2.8 mm.

[0457] The DSC of the crushed material is measured, and as a result, an endothermic peak of 2.1 J / g is observed between 200 °C and 250 °C.

[0458] In addition, the dichloromethane dissolution color of the crushed material is 420.

[0459] [Example 2-3]

[0460] (Solvent treatment process)

[0461] The solvent treatment time is set to 0.5 hour, and except for this, the treatment is carried out in the same manner as the solvent treatment process of Example 2-1 to obtain a solvent-treated headlight cover C.

[0462] (Crushing process)

[0463] The headlight cover C obtained in the foregoing solvent treatment process is put into a granulator for crushing. All the input amount is crushed. The size of the crushed material is measured, and the result is a size that passes through a sieve with a nominal mesh size of 4.75 mm but does not pass through a sieve with a nominal mesh size of 2.8 mm.

[0464] The DSC of the crushed material was measured, and an endothermic peak of 1.6 J / g was observed between 200 °C and 250 °C.

[0465] In addition, the dichloromethane solution color of the crushed material was 460.

[0466] [Example 2-4]

[0467] (Solvent treatment process)

[0468] The solvent treatment time was set to 24 hours, and except for this, the treatment was carried out in the same manner as the solvent treatment process of Example 2-1 to obtain a solvent-treated headlamp cover D.

[0469] (Crushing process)

[0470] The headlamp cover D obtained in the above solvent treatment process was put into a granulator for crushing. All the input amount was crushed. The size of the crushed material was measured, and the result was a size that passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm.

[0471] The DSC of the crushed material was measured, and an endothermic peak of 14.5 J / g was observed between 200 °C and 250 °C.

[0472] In addition, the dichloromethane solution color of the crushed material was 280.

[0473] [Example 2-5]

[0474] (Solvent treatment process)

[0475] The organic solvent used in the solvent treatment was changed from acetone to toluene, and except for this, the treatment was carried out in the same manner as the solvent treatment process of Example 2-1 to obtain a solvent-treated headlamp cover E.

[0476] (Crushing process)

[0477] The headlamp cover E obtained in the above solvent treatment process was put into a granulator for crushing. All the input amount was crushed. The size of the crushed material was measured, and the result was a size that passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm.

[0478] The DSC of the crushed material was measured, and an endothermic peak of 7.5 J / g was observed between 200 °C and 250 °C.

[0479] In addition, the dichloromethane solution color of the crushed material was 600.

[0480] [Example 2-6]

[0481] (Solvent treatment process)

[0482] The organic solvent used for solvent treatment was changed from acetone to dimethyl carbonate, and the treatment was carried out in the same manner as the solvent treatment process of Example 2-1 to obtain a solvent-treated headlamp cover F.

[0483] (Crushing process)

[0484] The headlamp cover F obtained in the above solvent treatment process was put into a granulator for crushing. All the input amount was crushed. The size of the crushed material was measured, and the result was that it passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm.

[0485] The DSC of the crushed material was measured, and as a result, an endothermic peak of 4.4 J / g was observed between 200 °C and 250 °C.

[0486] In addition, the dichloromethane dissolution color of the crushed material was 180.

[0487] [Example 2-7]

[0488] (Solvent treatment process)

[0489] The solvent treatment time was set to 0.1 hour, and the treatment was carried out in the same manner as the solvent treatment process of Example 2-1 to obtain a solvent-treated headlamp cover G.

[0490] (Crushing process)

[0491] The headlamp cover G obtained in the above solvent treatment process was put into a granulator for crushing. Part of the input was crushed, but during the crushing process, the headlamp cover bit into the coarse crushing knife, causing the device to stop and unable to be shredded. For the successfully crushed material, the size was measured, and the result was that it passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm.

[0492] The DSC of the crushed material was measured, and as a result, an endothermic peak of 0.4 J / g was observed between 200 °C and 250 °C.

[0493] In addition, the dichloromethane dissolution color of the crushed material was 510.

[0494] [Example 2-8]

[0495] (Solvent treatment process)

[0496] The organic solvent used in the solvent treatment was changed from acetone to toluene, and the treatment was carried out in the same manner as the solvent treatment process of Example 2-7 to obtain a solvent-treated headlamp cover H.

[0497] (Crushing process)

[0498] The headlamp cover H obtained in the aforementioned solvent treatment process was put into a granulator for crushing. A part of the input was crushed, but during the crushing process, the headlamp cover bit into the coarse crushing knife, causing the device to stop and unable to be shredded. For the successfully crushed material, the size was measured, and the result was a size that passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm.

[0499] The DSC of this crushed material was measured, and as a result, an endothermic peak of 0.6 J / g was observed between 200 °C and 250 °C.

[0500] In addition, the dichloromethane dissolution color of the crushed material was 730.

[0501] [Example 2-9]

[0502] (Solvent treatment process)

[0503] The organic solvent used in the solvent treatment was changed from acetone to dimethyl carbonate, and except for this, the treatment was carried out in the same manner as the solvent treatment process of Example 2-7 to obtain a solvent-treated headlamp cover I.

[0504] (Crushing process)

[0505] The headlamp cover I obtained in the aforementioned solvent treatment process was put into a granulator for crushing. A part of the input was crushed, but during the crushing process, the headlamp cover bit into the coarse crushing knife, causing the device to stop and unable to be shredded. For the successfully crushed material, the size was measured, and the result was a size that passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm.

[0506] The DSC of this crushed material was measured, and as a result, an endothermic peak of 0.3 J / g was observed between 200 °C and 250 °C.

[0507] In addition, the dichloromethane dissolution color of the crushed material was 200.

[0508] The results of Example 2-1 to 2-9 and Reference Example 1 were summarized in Table 3. By reading Table 3, it can be seen that the polycarbonate resin with a heat of fusion of 1.0 J / g or more obtained through solvent treatment has excellent crushability and is suitable as a recycling raw material.

[0509] [Table 3]

[0510]

[0511] [Reference Example 2]

[0512] The shed roof material was cut into 300 mm × 300 mm × 5 mm using a cutter, and a part was sampled using pliers in such a way as to include the entire thickness direction of the cut surface, and the DSC was measured. As a result, no endothermic peak was observed.

[0513] The shed roof material was put into a granulator for crushing. A part of the material put in was crushed, but during the crushing process, the headlight cover bit into the coarse crushing knife, causing the device to stop and unable to be shredded. For the successfully crushed material, the size was measured, and the result was a size that passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm.

[0514] <Example 3>

[0515] (Solvent treatment process)

[0516] 200 g of the shed roof material divided in Reference Example 2 was used instead of 200 g of the headlight cover of the car, and except for this, the treatment was carried out in the same manner as the solvent treatment process of Example 2-1 to obtain a solvent-treated shed roof material A.

[0517] A part of the solvent-treated shed roof material A was sampled and DSC was measured. As a result, an endothermic peak of 5.9 J / g was observed between 200 °C and 250 °C.

[0518] (Crushing process)

[0519] The shed roof material A obtained in the above solvent treatment process was put into a granulator for crushing. All the amount put in was crushed. The size of the crushed material was measured, and the result was a size that passed through a sieve with a nominal mesh size of 4.75 mm but did not pass through a sieve with a nominal mesh size of 2.8 mm.

[0520] <Example 4>

[0521] (Manufacture of bisphenol from the crushed product of the polycarbonate resin composition)

[0522] Under a nitrogen atmosphere, at room temperature, 100 g of the crushed product of the polycarbonate resin composition obtained in Example 2-4 (since the repeating unit of the polycarbonate resin is 254 g / mol, 100 g ÷ 254 g / mol = 0.394 mol), 300 g of phenol, and 107 g of a 7 mass% aqueous sodium bicarbonate solution were added to a jacketed separable flask equipped with a serpentine condenser, stirring blades, and a thermometer. The reaction solution was in a slurry state.

[0523] Then, the internal temperature was raised to 90 °C, and the reaction was carried out for 5 hours while maintaining 90 °C to obtain a homogeneous solution.

[0524] A 70% aqueous sulfuric acid solution was supplied to the obtained reaction solution until the aqueous phase reached pH 7.5, and as a result, carbon dioxide gas was generated. Then, stirring was stopped for oil-water separation, and the aqueous phase was taken out from the flask to obtain 489 g of organic phase 1.

[0525] Perform a compositional analysis on a part of the obtained organic phase 1 by high performance liquid chromatography to confirm the formation of bisphenol A.

[0526] Transfer the obtained organic phase 1 to a distillation apparatus equipped with a thermometer, a stirring blade, a distillation tube, and a pressure regulator. While observing the distillate amount, slowly raise the internal temperature to 130 °C and slowly lower the internal pressure from atmospheric pressure to 10 kPa, and distill off water and phenol until the distillation rate (distillate ÷ organic phase 1 × 100) reaches 75% by mass.

[0527] Then, repressurize the flask with nitrogen, lower the internal temperature to 80 °C, add 400 g of toluene and 50 g of water to obtain organic phase 2. Cool the obtained organic phase 2 to 10 °C to obtain a slurry. Filter the obtained slurry to obtain 105 g of a crude filter cake.

[0528] Supply the obtained crude filter cake again to a jacketed separable flask equipped with a serpentine condenser, a stirring blade, and a thermometer under a nitrogen atmosphere, add 600 g of toluene, and heat it to 80 °C with stirring to dissolve it to obtain organic phase 3.

[0529] Supply 100 g of water to organic phase 3 and stir for 15 minutes to wash organic phase 3. After 15 minutes, stop stirring, separate the organic phase and the aqueous phase into two phases, and remove the aqueous phase to obtain organic phase 4.

[0530] Repeat this operation 3 times to obtain organic phase 5. Cool the obtained organic phase 5 to 10 °C to obtain a slurry. Filter the obtained slurry to obtain 98 g of a filter cake.

[0531] Dry the obtained filter cake with a rotary evaporator to obtain 75 g of bisphenol A. Perform a compositional analysis and confirm that it is bisphenol A with a purity (area %) of 99.6%. The yield of bisphenol A is 83.5 mol% (75 g ÷ 228 g / mol ÷ 0.394 × 100 = 83.5).

[0532] <Example 5>

[0533] (Manufacture of recycled polycarbonate resin using bisphenol)

[0534] Add 10.00 g (0.04 mol of bisphenol A), 9.95 g (0.05 mol) of diphenyl carbonate, and 18 μL of an aqueous cesium carbonate solution of 400 mass ppm to a glass reaction tank with an internal volume of 45 mL equipped with a stirrer and a distillation tube. Reduce the pressure of this glass reaction tank to about 100 Pa, then restore it to atmospheric pressure using nitrogen, and repeat this operation 3 times to replace the inside of the reaction tank with nitrogen. Then, immerse this reaction tank in an oil bath at 220 °C to dissolve the contents.

[0535] Set the rotation speed of the stirrer to 100 times per minute. While distilling off phenol by-produced through the oligomerization reaction of bisphenol A and diphenyl carbonate in the reaction tank, reduce the pressure in the reaction tank from 101.3 kPa to 13.3 kPa with an absolute pressure gauge over 40 minutes.

[0536] Next, maintain the pressure in the reaction tank at 13.3 kPa. While further distilling off phenol, carry out the transesterification reaction for 80 minutes.

[0537] Then, raise the external temperature of the reaction tank to 290 °C, and reduce the pressure in the reaction tank from 13.3 kPa to 399 Pa with an absolute pressure gauge over 40 minutes, and remove the distilled phenol outside the system.

[0538] Then, reduce the absolute pressure of the reaction tank to 30 Pa and carry out the polycondensation reaction. When the stirrer of the reaction tank reaches a predetermined stirring power, end the polycondensation reaction. The time from raising the temperature to 290 °C to ending the polymerization is 120 minutes.

[0539] Next, after restoring the pressure in the reaction tank to an absolute pressure of 101.3 kPa with nitrogen, raise the pressure to a gauge pressure of 0.2 MPa, and extract the polycarbonate resin from the reaction tank to obtain the polycarbonate resin. The viscosity-average molecular weight (Mv) of the obtained polycarbonate resin is 26,300.

[0540] <Comparative Example 4>

[0541] Put the headlamp cover of an untreated car into a granulator for crushing. It should be noted that during the crushing process, the headlamp cover bit into the coarse crushing knife, causing the device to stop and unable to continuously carry out crushing. Whenever the device stopped, the bitten headlamp cover was removed and the crushing was repeated to obtain 100 g of crushed material.

[0542] Using 100 g of this crushed material, 71 g of bisphenol A with a purity of 99.6% was obtained in the same manner as in Example 4. The yield of bisphenol A was 79.0 mol%.

[0543] In addition, in Comparative Example 4, the headlamp cover pieces that bit into the coarse crushing knife needed to be discarded. Therefore, when comparing the yields from crushing the headlamp cover of a car to obtain bisphenol A in the total of Examples 2 - 4 and Example 4 and Comparative Example 4, the yield of Comparative Example 4 was lower.

[0544] <Example 6>

[0545] Collect the crushed material of the successfully crushed headlamp cover in Reference Example 1, and use a color difference meter to measure the brightness index L*. The average value of 5 measurements is L* = 67.0.

[0546] For the crushed product of the polycarbonate resin obtained in Example 2-1, the brightness index L* was measured using a color difference meter. The average value of 5 measurements was L* = 76.4.

[0547] The difference in the brightness index L* before and after the solvent treatment, ΔL*, was calculated by subtracting the brightness index L* of the crushed product before the solvent treatment from the brightness index L* of the crushed product after the solvent treatment. As a result, ΔL* was 76.4 - 67.0 = 9.4.

[0548] <Example 7>

[0549] The crushed product of the shed roof material successfully crushed in Reference Example 2 was collected, and the brightness index L* was measured using a color difference meter. The average value of 5 measurements was L* = 28.7.

[0550] For the crushed product of the polycarbonate resin obtained in Example 3, the brightness index L* was measured using a color difference meter. The average value of 5 measurements was L* = 53.1.

[0551] The difference in the brightness index L* before and after the solvent treatment, ΔL*, was 53.1 - 28.7 = 24.4.

[0552] The results of Examples 6 and 7 were summarized in Table 4. From Table 4, it can be seen that the crushed product of the polycarbonate resin obtained by solvent treatment is characterized in that the brightness index L* is higher, that is, the brightness is higher, than that of the raw material polycarbonate resin without solvent treatment.

[0553] [Table 4]

[0554]

[0555] <Example 8>

[0556] Using the crushed product of the polycarbonate resin obtained in Example 2-1 as the raw material, a test piece was produced using a small injection molding machine under the conditions described in [Tone Evaluation of Polycarbonate Resin Composition Molded Sheets] above, and the YI was measured. The YI was 15.6. During injection molding, the moldability was good and no abnormal odor was generated.

Claims

1. A method for manufacturing a modified polycarbonate resin composition, which comprises subjecting a waste polycarbonate resin composition having a dichloromethane solution color of 110 or more to solvent treatment by contacting it with a treatment solvent, so that the surface of the waste polycarbonate resin composition is dissolved in the treatment solvent to obtain a modified polycarbonate resin composition.

2. The method for manufacturing a modified polycarbonate resin composition according to claim 1, wherein the difference between the dichloromethane solution color of the waste polycarbonate resin composition and the dichloromethane solution color of the modified polycarbonate resin composition is 100 or more.

3. A method for manufacturing a modified polycarbonate resin composition, which comprises subjecting a waste polycarbonate resin composition having a brightness index L* of 20 to 80 to solvent treatment by contacting it with a treatment solvent, to obtain a modified polycarbonate resin composition having a difference in brightness index L* before and after solvent treatment of 5 or more.

4. The method for manufacturing a modified polycarbonate resin composition according to claim 1 or 3, wherein the contact time for contacting the waste polycarbonate resin composition with the treatment solvent is 1 minute or more.

5. The method for manufacturing a modified polycarbonate resin composition according to claim 1 or 3, wherein the volume ratio of the treatment solvent to the waste polycarbonate resin composition is 1 time or more.

6. The method for manufacturing a modified polycarbonate resin composition according to claim 1 or 3, wherein the boiling point of the treatment solvent is 150°C or lower.

7. The method for manufacturing a modified polycarbonate resin composition according to claim 1 or 3, wherein the treatment solvent is at least one selected from the group consisting of ketone solvents, aldehyde solvents, alcohol solvents, ether solvents, ester solvents, aromatic hydrocarbon solvents, and dialkyl carbonate solvents.

8. The method for manufacturing a modified polycarbonate resin composition according to claim 1, wherein the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is 1.0 J / g or more.

9. The method for manufacturing a modified polycarbonate resin composition according to claim 3, wherein the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is 1.0 J / g or more.

10. The method for manufacturing a modified polycarbonate resin composition according to claim 8 or 9, wherein the difference between the heat of fusion of the polycarbonate resin contained in the waste polycarbonate resin composition and the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is 0.5 J / g or more.

11. The method for manufacturing a modified polycarbonate resin composition according to claim 8 or 9, wherein the length of the maximum side of the waste polycarbonate resin composition is 1 mm or more and 1000 mm or less.

12. A method for manufacturing a modified polycarbonate resin composition, which comprises subjecting a waste polycarbonate resin composition having a length of the maximum side of 1 mm or more and 1000 mm or less to solvent treatment by contacting it with a treatment solvent, to obtain a modified polycarbonate resin composition having a heat of fusion of 1.0 J / g or more.

13. The manufacturing method of the modified polycarbonate resin composition according to claim 8, 9 or 12, wherein the difference between the heat of fusion of the polycarbonate resin contained in the waste polycarbonate resin composition and the heat of fusion of the polycarbonate resin contained in the modified polycarbonate resin composition is 1.0 J / g or more.

14. The manufacturing method of the modified polycarbonate resin composition according to claim 8, 9 or 12, wherein the treatment solvent contains an organic solvent having Hansen solubility parameters that simultaneously satisfy the following formulas (1) and (2). [Formula 1] Equation (1): {4×(18.8 - δd) 2 +(7.5δp) 2 +(5.6 - δh) 2} 0.5 > 5.6 Equation (2): {4 × (18.5 - δd) 2 + (10.6 - δp) 2 + (5.9 - δh) 2} 0.5 <10.1 In the above formulas (1) and (2), δd is the value of the energy derived from intermolecular dispersion force of the Hansen solubility parameter of the organic solvent, δp is the value of the energy derived from intermolecular polar force of the Hansen solubility parameter of the organic solvent, and δh is the value of the energy derived from intermolecular hydrogen bond force of the Hansen solubility parameter of the organic solvent.

15. The manufacturing method of the modified polycarbonate resin composition according to claim 14, wherein the organic solvent contains at least one or more selected from the group consisting of acetone, toluene, dimethyl carbonate, and phenol.

16. The manufacturing method of the modified polycarbonate resin composition according to claim 8, 9 or 12, wherein the contact time of the waste polycarbonate resin composition with the treatment solvent is 0.2 hours or more.

17. The manufacturing method of the modified polycarbonate resin composition according to claim 8, 9 or 12, wherein the treatment solvent contains an organic solvent and water.

18. The manufacturing method of the modified polycarbonate resin composition according to claim 8, 9 or 12, wherein the viscosity-average molecular weight Mv of the polycarbonate resin contained in the waste polycarbonate resin composition is 16,000 or more and 35,000 or less.

19. The manufacturing method of the modified polycarbonate resin composition according to claim 8, 9 or 12, wherein the waste polycarbonate resin composition contains other resins.

20. The manufacturing method of the modified polycarbonate resin composition according to claim 8, 9 or 12, wherein a crushing treatment is performed after the solvent treatment.

21. The manufacturing method of the modified polycarbonate resin composition according to claim 20, wherein the size of the modified polycarbonate resin composition after the crushing treatment is a size that passes through a sieve with a nominal mesh size of 53 mm specified in JIS-Z-8801-(2019) and does not pass through a sieve with a nominal mesh size of 90 μm.

22. A manufacturing method of bisphenol, after obtaining a modified polycarbonate resin composition by the manufacturing method of the modified polycarbonate resin composition according to claim 1, 3 or 12, depolymerizing the modified polycarbonate resin composition to obtain bisphenol.

23. The manufacturing method of bisphenol according to claim 22, wherein the bisphenol is 2,2-bis(4-hydroxyphenyl)propane.

24. A manufacturing method of a recycled polycarbonate resin, after obtaining bisphenol by the manufacturing method of bisphenol according to claim 22, using a bisphenol raw material containing the obtained bisphenol to manufacture a recycled polycarbonate resin.

25. A manufacturing method of a recycled polycarbonate resin composition, which has the following steps: A step of obtaining a modified polycarbonate resin composition by using the method for producing a modified polycarbonate resin composition according to claim 1, 3 or 12; and A step of melting the modified polycarbonate resin composition at 200°C or higher and 400°C or lower and then granulating it to obtain a recycled polycarbonate resin composition.

26. A polycarbonate resin composition comprising a polycarbonate resin having a heat of fusion of 1.0 J / g or more, wherein the length of the largest side of the polycarbonate resin composition is 5 mm or more and 1000 mm or less.

Images